ijcpe vol.9 no.3 (2008) iraqi journal of chemical and petroleum engineering vol.9 no.3 (december 2007) 37-41 issn: 1997-4884 effect of temperature on corrosion of carbon steel boiler tubes in dilute soduim chloride solution g.a. rassoul * and d.r. rzaige * * * chemical engineering department college of engineering university of baghdad – iraq * * ebn al-beetar research center abstract the corrosion behavior of carbon steel at different temperatures and in water containing different sodium chloride concentrations under 3 bar pressure has been investigated using weight loss method . the carbon steel specimens were immersed in water containing (100,400,700,1000ppm) of nacl solution and under temperature was increased from (90-120ºc) under pressures of 3 bar. the results of this investigation indicated that corrosion rate increased with nacl concentrations and temperature. keywords: oil corrosion, boiler tubes nacl solution introduction the corrosion of carbon steel occurs in neutral, slightly alkaline, high temperature water in boilers. the boiler steel itself will not normally be contact with the boiler water, because it quickly becomes covered with a layer of magnetite [1]. the formation of this magnetite layer is believed to take place in two stages. in the first stage, the steel reacts with the water, liberating hydrogen and forming ferrous hydroxide in absence of o2 according to the equation: 222 )(2 hohfeohfe  (1) this reaction is known to take place at 100ºc between steel and the water containing little or no dissolved oxygen. at temperature below about 570 ºc the ferrous hydroxide converted into magnetite [2]. 22432 2)(3 hohofeohfe  (2) the over all reaction in boiler may be written as: 2432 443 hofeohfe  (3) in water containing co2 a reaction take place between co2, calcium carbonate and water to form calcium bicarbonate which has solubility of a proximately 300-400 ppm at 25 ºc [3]. pitting corrosion of iron in alkaline solution occurred at definite potentials depend upon clcontent of the medium. similar to the behavior in acid solution ,gelatin in small concentration was effective in preventing pit formation .large concentration of additive promoted localized attack ,though to a lesser extent than in its absence [4] .there are many factors effect pitting such as: impurities ,stress, dissolved oxygen, copper impurities in water ,deposits [5]. experimental procedure a schematic diagram of the autoclave used in this investigation is shown in fig.(1).the cylindrical shape autoclave, had a wall thickness of approximately 12mm, heating tape surrounded the outside the autoclave, temperature controller, pressure gauge recorder, n2 gas cylinder, sensor record temperature and control valve to get rid of excess steam. university of baghdad college of engineering iraqi journal of chemical and petroleum engineering effect of temperature on corrosion of carbon steel boiler tubes in dilute soduim chloride solution 2 ijcpe vol.9 no.3 (2008) maximum capacity of the autoclave is 1700 ml of solution. the carbon steel specimen materials used in this investigation has the chemical composition shown in table (1): table 1 the chemical composition analysis of carbon steel fe 70.2 si 1.8 mn 9.2 cr 2.1 ni 1.7 mo 2.8 cu 1.2 co 2.6 al 3.8 c 3.0 s 1.6 hb* 3.5 total elements% 100 where *hb: hardness brinle the rectangular carbon steel alloy specimens of dimensions about (10 x 3 x 0.2 cm) have been used in this investigation; their surfaces were abraded by using emery paper of different grade numbers 220, 320, 400, 600. after abrasion the surfaces were cleaned with running tap water , followed by acetone rinse for 5 minutes and were dried in discator. fig. 1: schematic diagram of the experimental apparatus. different nacl solutions were prepared using 2000 mg of dried cooled nacl dissolved in one liter of distilled water to obtain 2000 ppm of nacl. this concentrated stock solution was diluted with deionized water to obtain (100ppm, 400ppm, 700ppm, 1000ppm), taking 65ml, 260ml, 455ml, 650ml, of 2000ppm of stock solution and diluted with deionized water to obtain 1300ml of above nacl concentration. after specimen's preparations, weighing the specimen and record (w1), the specimen was clamped and immersed in nacl solution in the autoclave, n2 gas cylinder with heating was used till the gauge pressure read 3 bars. these specimens were immersed in between 2 to 3 hours, after that, heating was cut off and then specimens were removed and cleaned by washing with running tap water and brushing them with bristle brush. then the specimens were immersed in benzene for 5 minutes to ensure removal of corrosion products from the metal surface. the specimens were immersed in ethanol and dried, then kept in discator, and then the dried sample weighed as (w2). corrosion rate was expressed by weight loss per unit area per unit time in (gmd). the surface area of the three specimens evaluated and founded to be about 65cm2. results and discussion 1. temperature effects: the effect of temperature in the range (90-120oc) indicates that higher temperature increase the electrochemical reaction and hence increase corrosion rate of carbon steel. but at low about 100 ppm nacl concentrations the effects of temperature is slight as shown in table (2) and fig. (2). 2. soduim chloride concentration effects: the results indicate that sodium chloride concentration greatly increase the electrochemical reaction between carbon steel specimen and sodium chloride solution. therefore it can be observed that concentration of nacl is greatly affects electrochemical reaction. as shown in the following equation and figs. (3and 4). 222 h fecl 2naoh h 2 2nacl  ofe g.a. rassoul and d.r. rzaige ijcpe vol.9 no.3 (2008) fig. 2: rusting of iron immersed in salt solution in autoclave 0 0.5 1 1.5 2 2.5 3 3.5 4 80 90 100 110 120 130 temp. (c) c .r . (g m d ) 100 ppm 400 ppm 700 ppm 1000 ppm linear (700 ppm) linear (400 ppm) linear (100 ppm) linear (1000 ppm) fig.3: corrosion rate/ temp. relationship for carbon steel in different nacl conc. and at 3 bar. 0 0.5 1 1.5 2 2.5 3 0 200 400 600 800 1000 1200 conc. (ppm) c .r . (g m d ) 90 c 100 c 110 c 120 c power (120 c) power (110 c) power (100 c) power (90 c) fig.4: corrosion rate/ conc. relationship for carbon steel at different temp. and at 3 bar run no. nacl conc.(ppm) temp. c0 c.r. (gmd) c.r. mm/y 1. 100 90 0.44 0.0205 2. 100 100 0.47 0.0218 3. 100 110 0.49 0.022 4. 100 120 0.53 0.024 5. 400 90 0.96 0.044 6. 400 100 1.10 0.051 7. 400 110 1.31 0.06 8. 400 120 1.47 0.068 9. 700 90 1.52 0.070 10. 700 100 1.66 0.077 11. 700 110 1.91 0.088 12. 700 120 2.14 0.099 13. 1000 90 1.89 0.087 14. 1000 100 2.21 0.102 15. 1000 110 2.52 0.117 16. 1000 120 2.94 0.136 where mm/y : millimeter per year. conclusions corrosion rate increases rapidly with nacl concentration in all different temperature at 3 bar i.e. corrosion rate increase from 0.44 to 2.94 gmd when nacl concentration from 100 up to1000 ppm. corrosion rate increases with temperature linearly at 700 ppm nacl concentration .i.e. corrosion rate increases from 1.52 up to 2.14 gmd when temperature increases from 90 to 120oc at 3 bar. therefore is recommended to operate the boilers with nacl concentration up to 700 ppm before shut down and removing salts concentration will greatly damage metallic boilers. reference 1. herbert h. uhlig, r. winston revie, "corrosion and corrosion control", 3rd ed, u.s.a (1985). 2. john wiley and sons" water treatment hand book", 5th ed new york, (1979). 3. g.a. cappeline," principles of industrial water treatment", 1st ed new york, (1977). 4. f.m.abdle wahab and a.m. shaams eldin, “effect of gelation on pitting corrosion of iron in acid and alkaline solution“, british corrosion journal p.39, vol. 13. no.1, (1978). 5. herbert h. uhlig allen g. gary," the corrosion hand book", new york, (1961) iraqi journal of chemical and petroleum engineering vol.18 no.3 (september 2017) 59 65 issn: 1997-4884 permeability prediction by classical and flow zone indictor (fzi) methods for an iraqi gas field waffa mustafa al-qattan and ahmed habeeb al mohammed petroleum engineering department-college of engineering-university of baghdad-iraq abstract the permeability is the most important parameter that indicates how efficient the reservoir fluids flow through the rock pores to the wellbore. well-log evaluation and core measurements techniques are typically used to estimate it. in this paper, the permeability has been predicted by using classical and flow zone indicator methods. a comparison between the two methods shows the superiority of the fzi method correlations, these correlations can be used to estimate permeability in un-cored wells with a good approximation. key words: permeability, fzi method introduction rock permeability is a property of a porous medium that quantifies the capacity of a rock to transmit the fluids. in other word, it is a measure of fluid conductivity of a porous media. it is an important rock property and one of the most difficult of all petrophysical properties to predict and determine. an accurate estimate of permeability is essential because it is considered the key parameter that controls strategies of reservoir management, well completion and production. core analysis has been traditionally used to determine permeability. kozeny (1927) and archie (1942) were amongst the first few people to determine permeability based on electrical measurements made on core sample . frequently, core analysis data are not available because of the high cost of coring and due to the borehole condition. thus, there are alternative methods can been made to predict and estimate permeability.one of the inexpensive and readily available sources of inferring permeability is from well logs. to achieve this goal, various models have been used and developed correlations to determine permeability based on well log measurements. the studied field is mansuriyah gas field at the east of iraq fig (1), and the studied reservoir of this field is jeribe formation. available core data for wells (mn-1, mn-2, mn-3 , mn-4) provide information for jeribe formation that can be depended to predict permeability by two methods were chosen in this study . university of baghdad college of engineering iraqi journal of chemical and petroleum engineering permeability prediction by classical and flow zone indictor (fzi) methods for an iraqi gas field 60 ijcpe vol.18 no.3 (sep. 2017) -available online at: www.iasj.net fig. 1, almansuriya field location the two different methods of permeability-porosity relationships used to predict permeability are classical and flow zone indicator (fzi) method. classical method for permeability prediction in this method, permeability can be directly derived from porosity. by using empirical correlation between permeability and porosity that generated from core data, permeability can be predicted in un-cored well sections. the general form for the conventional permeability-porosity relationship is usually expressed as(1): ( ) … (1) k: permeability (md). : porosity (fraction) and a and b : the constants to be fitted to the case study. available core samples data for four wells mn-1, mn-2, mn-3 and mn-4 collected together to generate empirical correlation of permeability vs. porosity for jirebe unit. figure (2) shows permeability vs. porosity plot that used to drive permeability model for jeribe unit and the formula for the equation with correlation coefficient ( r ) . this low percent for ( r ) coefficient refers to high heterogeneity . the increase in permeability does not necessary lead to increase in porosity and the increase in porosity does not necessary lead to increase in permeability. the limitation in the classical method that the porosity value is not the only parameter affecting permeability. table (1) shows the formula, correlation coefficient and sample number was used to generate permeability formula. table 1, classical permeability formula and correlation coefficient formation formula samp le no. correlation coefficient (r) jeribe k=0.063 x e 17.7770 451 0.4363 fig. 2, core porosity and permeability for jeribe formation waffa mustafa al-qattan and ahmed habeeb al mohammed -available online at: www.iasj.net ijcpe vol.18 no.3 (sep. 2017) 61 correlation between porosity and permeability applied for jeribe formation. figures (3) to (6) show predicted permeability for four wells , the figures show that predicted permeability doesn’t strongly matched with the measured core permeability , due to the permeability – porosity classical correlation which is basic method where permeability depend on porosity only and does not cover all factors effect on permeability ( pore scale and structure). fig. 3, predicted permeability for well mn-1 by classical method fig. 4, predicted permeability for well mn-2 by classical method fig. 5, predicted permeability for well mn-3 by classical method permeability prediction by classical and flow zone indictor (fzi) methods for an iraqi gas field 62 ijcpe vol.18 no.3 (sep. 2017) -available online at: www.iasj.net fig. 6, predicted permeability for well mn-4 by classical method flow zone indicator method (fzi) (2)(3)(4) among the various quantitative rocktyping techniques were presented, the hydraulic flow unit method (rqi/fzi) is more widely used. a hydraulic flow unit (hfu) is defined as the representative volume of total reservoir rock within which geological properties that control fluid flow are internally consistent and predictably different from properties of other rocks. this method is based on physics of flow in pore scale and geological parameters .the flow zone indicator (fzi) method for classifying core data into hydraulic units with specific fzi. this approach provides accurate correlations between permeability and porosity if fzi of the reservoir rock is known. fzi is estimate from core data in the cored wells and it is usually applied to un-cored wells through correlations with log attributes. in this approach, rock types are classified according to the following equations: √ … (2) = ( ) … (3) by substitute rqi and φz with fzi can be simplified as: … (4) by taking the logarithm of both side of equation (4), the final approach can written as follow: = ( ) … (5) the above equation represents the straight line on log-log plot of rqi vs. φz. the intercept of straight line at φz=1 is the specific flow zone indicator of each group. other fzi values of core samples will show on different lines. points that lie on the each straight line got same pore throat description and, therefore, same a flow unit. according to values of fzi four groups identified in permeability– porosity plot in figure (7) and permeability formula generated for each group. the generated permeability formulas applied in uncored wells and intervals depending on porosity value from log. waffa mustafa al-qattan and ahmed habeeb al mohammed -available online at: www.iasj.net ijcpe vol.18 no.3 (sep. 2017) 63 fig. 7, cross plot log permeability vs. porosity for specific fzi values for jeribe formation the generated permeability formulas tabulate in table (2) applied in cored well (mn-1 , mn-2, mn-3 and mn-4) to compere the predicted permeability values with measured core values as shown in figure form(8) to (11). table 2, fzi permeability formula for jeribe formation fzi permeability formula r 2 fzi=0 k=99.128xѳ 3.1643 0.7529 fzi=1 k=454.8xѳ 3.3544 0.891 fzi=2 k=1643.7xѳ 3.5632 0.8623 fzi=3 k=1786xѳ 2.8709 0.9326 fig. 8, predicted permeability for well mn-1 by fzi method fig. 9, predicted permeability for well mn-2 by fzi method permeability prediction by classical and flow zone indictor (fzi) methods for an iraqi gas field 64 ijcpe vol.18 no.3 (sep. 2017) -available online at: www.iasj.net fig. 10, predicted permeability for well mn-3 by fzi method fig. 11, predicted permeability for well mn-4 by fzi method comparison between permeability methods for estimating best method two permeability prediction methods (classical and fzi) were used in this chapter that’s covered the usefulness parameter that effect in permeability. to suggest the best method for this study, sample correlation made between measured and predicted permeability for two methods in order choose the method that gives the highest correlation coefficient. from the figures (12) and (13) shows that fzi method correlation gives the highest correction coefficient form classical method so it depended for permeability prediction in this study. fig. 12, accuracy of permeability prediction by fzi method waffa mustafa al-qattan and ahmed habeeb al mohammed -available online at: www.iasj.net ijcpe vol.18 no.3 (sep. 2017) 65 fig. 13, accuracy of permeability predictions by classical method conclusions 1the correlations developed to predict permeability using only porosity for jeribe formation is found to be unsuccessful due to the heterogeneity of jeribe formation. 2the estimated results of permeability using of fzi method is more accurate comparing with the classical method and greatly enhances the prediction of permeability. nomenclatures 1symbols a , b : constant are statistically determined. fs : effective pore throat shape factor. k: permeability (md) r 2 : correlation coefficient (dim.) :porosity (fraction) 2abbreviations fzi : flow zone indicator hfu: hydraulic flow unit rqi: reservoir quality index references 1taslimi,m.,bohloli,b.,kazemzad, e and kamali, m.r,"determining rock mass permeability in a carbonate reservoir, southern iran using hydraulic flow unitsand intelligent systems", college of science, university of tehran, research institute of petroleum technology, n.i.o, 2 nd edtion,uk, (2008). 2balan,b.,mohaghegh,s.andameri,s., "state of the artin permability determination from well log data : part 1a comparative study, model development",spe30978,westvirginia ,u.s.a. ,(1995). 3semmelbeck,m.e.and diyashev,i.r., "application of permlog–a new log based permeability estimation method", spe35650,calgry,(1996). 4lim,s.j. and kim,j. ,"reservoir porosity and permeability estimation from well logs using fuzzy logic and neural networks",spe 88476 , (2004). iraqi journal of chemical and petroleum engineering vol.15 no.1 (march 2014) 7377 issn: 1997-4884 oxidation of toluene to benzoic acid catalyzed by modified vanadium oxide wadood t. mohammed chemical engineering departmentcollege of engineeringuniversity of baghdad abstract a variety of oxides were examined as additives to a v2o5/al2o3 catalyst in order to enhance the catalytic performance for the vapor phase oxidation of toluene to benzoic acid. it was found that the modification with moo3 greatly promoted the little reaction leading to improve catalyst performance in terms of toluene conversion and benzoic acid selectivity. the effect of catalyst surface area, catalyst promoters, reaction temperature, o2/toluene, steam/toluene, space velocity, and catalyst composition to catalyst performance were examined in order to increase the benzoic acid selectivity and yield. introduction the yield of benzoic acid in the vapor phase oxidation of toluene remains far from a commercial production level because of the low toluene conversion and the poor selectivity to benzoic acid. although, a great number of studies of the reaction have been performed for years [1-10]. at present, vanadium oxide, commonly used for partial oxidation of aromatic hydrocarbons, is widely accepted as the active species which effectively yields benzoic acid and it is considered to be very difficult to enhance the benzoic acid yield which is about 30% at most. recently, the mechanism of toluene oxidation in the vapor phase has been investigated by anderson [4] and zhu and anderson [5] and its reaction network has become apparent with benzyle cation on the catalyst presented to be the precursor. however, it still has been an open question regarding a specific method on how to improve catalytic performance for the reaction. in the present work, we tried to modify the locally prepared v2o5.al2o3 catalyst with some oxides in order to improve the catalyst performance. experimental work 1. catalyst 100 g of v2o5.moo3.al2o3 catalyst with a composition of 5 wt.% v2o5 and 5 wt.% moo3 was prepared by impregnation method. a commercially available α-alumina oxide was used as the carrier material. the carrier has macro-porous so that the specific surface area is relatively low, namely about 5 m2/g. the carrier material was calcined for 24 h at a temperature of 1150 ˚c (1423 k) and then mixed with a water solution of nh4vo3 in such a proportion (8 g in 30 ml) that the solution could just be absorbed by the carrier material. the molybdenum was added by impregnation of v2o5.al2o3 using the same procedure except that iraqi journal of chemical and petroleum engineering university of baghdad college of engineering oxidation of toluene to benzoic acid catalyzed by modified vanadium oxide 74 ijcpe vol.15 no.1 (march 2014) -available online at: www.iasj.net the impregnation solution prepared by dissolving 6 g of ammonium molybdenum in 20 ml of deionized water (or 15 g of cobalt nitrate in 30 ml of water). followed by drying at 120 ˚c for 2 hours and then calcining in air at 500 ˚c for 3 hr. 2. apparatus and procedure the feed was heated prior to entrance into the reactor. the heating solution is divided into three separate sections; steam generator, air heater using heating tape, and round bottom flask heated by a mantle heater to heat the toluene. heating is controlled by voltage regulators. the oxidation reactor is made of qvf glass with an inner diameter of 2.54 cm and a length of 50-70 cm. the reactor is divided into two zones. the entrance zone (30 cm long), serving as a preheater section, was packed with glass balls. the reaction zone, the length of which depends on the space velocity, was packed with the catalyst. both zones are heated with a heating tape controlled by a voltage regulator. the oxidation products are cooled and condensed in two glass condensers in series and collected in a glass flask. cooling is achieved by tap water. the temperature is measured in various locations along the system by thermocouples type j. while the toluene and steam were heated, the reaction zone was also heated up to the desired temperature in hot air flow, and then the feed introduced and mixed in the entrance of the preheating reactor section. the oxidation products of unreacted toluene, benzoic acid, benzaldehyde, benzene, and other products were collected in a cold trap and analyzed by gas chromatography (pye unicam) using thermal conductivity detector. results and discussion 1. effect of catalyst surface area it is obvious that the calcinations temperature is one of the most important factors which affect the catalyst activity, indicating that the low surface area causes a significant increase in the benzoic acid selectivity. appropriate surface area is revealed to be about 5 m2/g to obtain best conversion and benzoic acid selectivity. these results suggest that an increase in micropores or mesopores of the catalysts is not effective for the selective formation of benzoic acid, implying that too strong adsorption of toluene in the micropores accelerates the complete oxidation to co and co2. the drop in conversion at high calcinations temperature is obviously caused due to the decrease in surface area. optimum benzoic acid selectivity was obtained at the calcinations temperature of 1150 ˚c (1423k) as shown in table l. table l, results of experimental runs for different catalyst surface area effect * surface area m2/g molar ratio toluene/air/steam space velocity h-1 conversion% toluene selectivity% benzoic acid benzaldyhide benzene others 0.3 1/8/20 2100 27.2 62.5 17.7 14.5 5.9 0.3 1/10/30 2560 32.8 64.1 15.0 16.3 4.6 5 1/8/20 2050 42.1 64.5 16.2 14.2 5.1 5 1/10/30 2480 48.2 67.8 18.3 11.7 2.2 100 1/8/20 1995 58.1 38.1 35.8 24.0 2.1 100 1/10/30 2420 60.6 35.2 32.0 20.0 12.8 200 1/8/20 2080 65.4 30.5 40.2 20.2 9.1 200 1/10/30 2510 69.3 28.6 43.1 21.1 7.2 *catalyst used v2o5.moo3/al2o3 in the composition of 5 wt.% v2o5 and 5 wt.% moo3. calcination temp.: 1200, 1150, 700, and 350 ˚c respectively. catalyst weight 100g. reaction temp.: 350 ˚c (623 k) http://www.iasj.net/ wadood t mohammed -available online at: www.iasj.net ijcpe vol.15 no.1 (march 2014) 75 2. effect of catalyst promoters preferably, the catalyst to be used in the process comprises activating additives, in one compound of cobalt or molybdenum, beside the vanadium oxide. table 2 shows that molybdenum oxide was active than cobalt for the conversion of toluene and benzoic acid selectivity. table 2, results of experimental runs for catalyst promoters effect* catalyst molar ratio toluene/air/steam space velocity h-1 conversion% toluene selectivity% benzoic acid benzaldyhide benzene others v2o5.coo3. al2o3 1/8/20 2100 42.1 54.5 17.2 15.2 13.1 1/10/30 2560 48.2 57.8 19.3 18.7 4.2 v2o5.moo3. al2o3 1/8/20 2120 53.2 72.2 6.1 11.3 10.4 1/10/30 2520 58.3 76.3 5.3 14.2 4.2 *catalyst surface area, 5 m2/g. catalyst used v2o5.co2o3.al2o3 with 5 wt.% v2o5 and 5 wt.% co2o3. v2o5.moo3.al2o3 with 5 wt.% v2o5 and 5 wt.% moo3. catalyst weight 100g. reaction temp.: 350 ˚c. 3. effect of reaction temperature the results clearly demonstrate that increasing the reaction temperature up to 350 ˚c causes the conversion, benzoic acid selectivity to increase, beyond that the benzoic acid selectivity decrease. table 3 shows the effect of reaction temperature on catalyst activities. a gradual decrease in benzoic acid selectivity was probably due to the enhanced oxidation of benzoic acid to co and co2. table 3, results of experimental runs for reaction temperature effect* temp. ˚c conversion % toluene selectivity% benzoic acid benzaldyhide benzene others 250 41.8 58.2 6.3 11.8 23.7 300 49.7 65.0 6.7 10.2 18.1 350 58.3 76.3 5.3 14.2 4.2 400 68.2 48.7 11.1 16.0 24.2 *catalyst surface area, 5 m2/g. catalyst used moo3.al2o3 with 5 wt.% v2o5 and 5 wt.% moo3. catalyst weight 100g. molar ratio (toluene/air/steam) of 1/10/30. space velocity 2520 h-1. 4. effect of oxygen ratio figs. l and 2 exhibits the effect of the o2/toluene molar ratio on catalytic activity with increasing molar ratio up to 2.52 (for air this ratio is 12) leading to a better catalytic performance both in benzoic acid selectivity and toluene conversion. complete combustion products appeared to increase above an oxygen molar ratio of 2.52. fig. 1, effect of air molar ratio on conversion of toluene http://www.iasj.net/ oxidation of toluene to benzoic acid catalyzed by modified vanadium oxide 76 ijcpe vol.15 no.1 (march 2014) -available online at: www.iasj.net fig. 2, effect of air molar ratio on selectivity of beenzoic acid 5. effect of stream ratio the effect of water on the catalytic oxidation of hydrocarbons has been observed frequently. the results show that water addition improves both the activity and the selectivity to benzoic acid. it is suggested to be due to hydrolysis of adsorbed benzoate species at the higher concentration of surface hydroxyl groups caused by the water addition or directly by water. fig. 3, effect of steam molar ratio on conversion of toluene fig. 4, effect of steam molar ratio on selectivity of toluene figs. 3 and 4 shows the effect of steam/toluene molar ratio on the catalyst activities. toluene conversion and benzoic acid selectivity appeared small decrease a strem/toluene ratio of 30. while the benzoic acid selectivity showed a rapid decrease below steam/toluene molar ratio of 25. 6. effect of space velocity table 4 exhibits the effect of the space velocity on catalyst performance. the toluene conversion decreased with a rise in space velocity. it has been shown that with space velocities above 2450 h-1, the desired product can be produced in good yield with short residence time. moreover, the formation of oxidative decomposition is reduced to a minimum. it is therefore, generally possible to rise the space velocity to as much as approximately 2580 h-1 l gaseous feed / l cat.h. table 4, results of experimental runs for space velocity effect* catalyst weight (g) space velocity h-1 conversion % toluene selectivity % benzoic acid benzaldyhide benzene others 50 3430 40.3 53.2 2.8 19.0 25 75 3160 51.1 70.8 3.1 16.1 10.8 100 2580 65.6 80.0 4.2 12.8 3 125 2318 69.1 69.3 11.8 15.0 3.9 150 1991 74.3 58.1 14.3 16.2 11.4 *catalyst surface area, 5 m2/g catalyst used v2o5.moo3.al2o3 with 5 wt% v2o5 and 5 wt% moo3, reaction temp. 350 oc. molar ratio toluene/air/steam 1/12/30. http://www.iasj.net/ wadood t mohammed -available online at: www.iasj.net ijcpe vol.15 no.1 (march 2014) 77 7. effect of catalyst composition the results exhibit that small proportion of v2o5 and moo3 in the catalyst are required. it has been found that even as little as 5 wt% v2o5 and 5 wt% moo3 were sufficient for obtaining smooth conversion with good selectivity as shown in table 5. table 5, results of experimental runs for catalyst composition effect * catalyst composition v2o5 moo3 conversion % toluene selectivity % benzoic acid benzaldyhide benzene others 2 2 41.2 80.9 5.2 11.2 2.7 5 5 65.6 80.0 4.2 12.8 3 10 10 66.1 76.3 8.1 14.2 1.4 *catalyst surface area, 5 m2/g catalyst used v2o5.moo3.al2o3 with 5 wt% v2o5 and 5 wt% moo3, reaction temp. 350 oc. molar ratio toluene/air/steam 1/12/30. space velocity 2580 h-1. conclusions great enhancements of catalyst performance has been achieved by the modification of v2o5.al2o3 with moo3 addition of 5 wt% of moo3 to a v2o5. al2o3 catalyst is revealed to be effective for the enhancement of catalyst performance in terms of toluene conversion and benzoic acid selectivity. but other additives such as co2o3 showed no improvement of the v2o5.al2o3 catalyst performance. the best reaction conditions are: molar ratio of toluene to air to steam, space velocity, and reaction temperature are 1/12/30, 2580 h-1, and 350 oc respectively. references 1 n. k. nag. t. fransen and p. mars. j. catal. 68 (1981) 77. 2 a. j. van hengstum, j. g. van ommen, appl. cata., 8 (1953) 369. 3 a. j. van hengstun, j. g. van ommen, appl. catl., 11 (1984) 317. 4 s. l. t. anderson, j. catal., 98 (1986) 138. 5 j. zhu and s. l. t. anderson, j. catal., 126 (1990) 92. 6 e. t. c. vogt, m. debore, appl. catal., 40 (1988) 255. 7 z. yan and s. l. t. anderson, j. catal., 131 (1991) 350. 8 j. zhu and s. l. t. anderson, appl. catl., 53 (1989) 251. 9 y. sasaki and h. yamanoto, syokubal (catalyst), 36 (1994) 123. 10 jun miki, yo osada, appl. catal., 137 (1998) 93-104. http://www.iasj.net/ iraqi journal of chemical and petroleum engineering vol.9 no.4 (december 2008) 29-33 issn: 1997-4884 study of the performance of batch reactive distillation column dr. cecilia k. haweel * and taha m.a. hamza ** * chemical engineering department college of engineering university of baghdad – iraq ** ministry of oilcom. of north refineries abstract batch reactive distillation was studied in packed bed column. esterification of methanol with acetic acid to produce methyl acetate and water with homogenous sulfuric acid as a catalyst was considered. this system was chosen because the reaction is reversible and the boiling point of reactant and products are different. the reaction was carried out with and without distillation column and shows that the reactive distillation is more efficient from the conventional process (reactor and then separation). the conversion of acetic acid and concentration of methyl acetate increase by (30.43% and 75.14%) respectively at the best condition (reflux ratio 2, feed mole ratio 2 and batch time 90 minute). the influence of various parameters, such as batch time, reflux ratio, and feed mole ratio (methanol to acetic acid) on the performance of the batch reactive distillation column was studied, through the effect of the concentration of product and conversion of reactant. the results obtained for the non-ideal packed bed reactive batch distillation column show that the conversion of acetic acid is 90% at the best condition reflux ratio 2, feed mole ratio 2, and batch time 90 minute introduction in recent years, increasing attention has been directed towards reactive distillation process as alternative to conventional processes (reactor and then separation). this has led to the development of a variety of techniques for reactive multistage column; however the problem of design and synthesis of batch reactive distillation processes have not yet been addressed [1]. most of the distillation synthesis studies to date have been concerned with multi component non-ideal mixtures. the main advantages of this process relative to the conventional alternatives are the possibility of carrying equilibrium–limited chemical reaction to completion, and the simultaneous separation of the reaction products in only one unit .this reduces or eliminates reactor and recycle costs. this advantages of reactive distillation, and flexibility of a batch process can be combined in batch reactive distillation device, and the effect of operating parameter on yield and selectivity is studied [2]. the aim of the present work is to study the efficiency and the characteristics of the batch reactive distillation process and distinguished between it and the conventional reactor – distillation process. the present work provides a process for the production high purity methyl acetate from methanol and acetic acid, to study the effect of major variables (such as batch time, reflux ratio, and feed mole ratio) on the conversion of acetic acid and the concentration of methyl acetate in the product. experimental work a schematic sketch of the apparatus is illustrated in figure (1). it is comprised of all items, flask with two necks, one for the thermometer to measure the temperature at the still (vapor temperature) and the other connected to 3cm diameter and 57cm length distillation university of baghdad college of engineering iraqi journal of chemical and petroleum engineering study of the performance of batch reactive distillation column ijcpe vol.9 no. 4 (2008) 30 column. packed with packing to a height of 30cm. the distillation column connected at the top with a thermometer to measure the top distillation temperature. the raising vapor from the distillation column was condensate by a condenser. the condense accumulates in the receiver which has two necks one for product through valve (1) and the other return back to the distillation column as reflux with fixed ratio (r) through valve (2). dosing pump was used to control the quantity of the reflux to the distillation column. heat was supplied to the still by electrical heater and was controlled on the temperature of the component in the still to desired value by using a variac. fig. 1: sketch of the experimental equipment selection of liquidliquid system the reaction of methyl acetate with acetic acid in the presence of sulfuric acid as homogenous catalyst to produced water and methyl acetate is: h2so4 ch3cooh+ch3oh ch3cooch3 + h2o specification of variables the variables considered for the present work are: areflux ratio (0, 1, 2, and 3). bfeed mole ratio (1, 1.5, 2, and 2.5) of methanol to acetic acid. cbatch time (40, 60, 90, and 120 minute) these variables are studied and the results are compared with previous work. results and discussion variable effect on product concentration -effect of batch time figure (2) shows the relation between concentration of methyl acetate against time at variable feed mole ratio and constant reflux ratio (2). form this figure it clear that the concentration of methyl acetate increase sharply up to (20) minute then it begin to increase slightly to value of (60) minute after that it remain constant, for a period of time depend on feed mole ratio and then decrease. at a low mole ratio along time is required for the concentration to be reduced because of the low mole ratio consist of high percent of acetic acid, methanol return to the still through the reflux and react with residual acetic acid to produce methyl acetate. for a high mole ratio, a short time is required for the concentration to be reduced. that mean a low percent of acetic acid which can be consumed rapidly and then concentration of methanol in the distillate will be increase to reduce the concentration of methyl acetate. fig. 2: concentration of methyl acetate vs. time at reflux ratio=2 and different feed mole ratio -effect of reflux ratio figure (3) shows the relation of methyl acetate concentration against reflux ratio for a batch time 90 minute and different feed mole ratio. this figure shows that the maximum concentration is at reflux ratio equal to (2) for all feed mole ratio except the value of feed mole ratio (2.5) where in this feed mole ratio the concentration increase directly mainly in straight line as it be explained previously. from this figure it can be deduced that the best reflux ratio is (2). v1 v2 time ( min) m e a c c o n c e n tr a ti o n (v o l. % ) 0 10 20 30 40 50 60 70 80 90 100 0 10 20 30 40 50 60 70 80 90 100 110 120 130 fmr=1 fmr=1.5 fmr=2 fmr=2.5 dr. cecilia k. haweel and taha m.a. hamza 31 ijcpe vol.9 no. 4 (2008) fig. 3: concentration of methyl acetate vs. reflux ratio at 90 minute and different feed mole ratio. -effect of feed mole ratio figure (4) show the concentration of methyl acetate against feed mole ratio at variable reflux ratio and constant time. the figures represented that if the mole ratio increase the concentration will decrease, because of if the percent of methanol increase in feed, it will vaporize more than methyl acetate, causes decrease of methyl acetate concentration. fig.4: concentration of methyl acetate v.s. feed mole ratio at 90 minute and different reflux ratio variable effect on conversion of acetic acid effect of batch time figure (5) shows the conversion of acetic acid against batch time for variable feed mole ratio and constant reflux ratio 2. this figure shows that the conversion of acetic acid increase slightly up to (60) minute then increase sharply up to the (120) minute as an over all the conversion of acetic acid increase with time due to the increase of consumption of acetic acid with time which cause a high conversion value. fig.5: conversion of acetic acid v.s. time at r=2 and different feed mole ratio. effect of reflux ratio figure (6) shows the conversion against reflux ratio at constant batch time 90 minute and different feed mole ratio. from this figure the conversion of acetic acid increase with reflux ratio up to reflux rate (2) and then decrease for all value of feed mole ratio, except for feed mole ratio (2.5) which shows a maximum value of conversion at reflux ratio equal to(1) this is in agreement with (kai 6 , agreda 7 , and doherty 8 ). this is because of at increase reflux ratio, the distillate is rich in methyl acetate and when it return to the still, the reversible reaction is occurred and more acetic acid is produced which causes a decrease in the conversion of acetic acid. fig. 6: conversion of acetic acid v.s. reflux at 90 minute and different feed mole ratio reflux m e a c c o n c e n tr a ti o n (v o l. % ) 58 64 70 76 82 88 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 fmr=1 fmr=1.5 fmr=2 fmr=2.5 feed mole ratio m e a c c o n ce n tr a ti o n ( vo l. % ) 35 45 55 65 75 85 95 0.8 1.2 1.6 2.0 2.4 2.8 r=0 r=1 r=2 r=3 r= tim e(min) c o n v e r s io n 60 65 70 75 80 85 90 95 100 30 50 70 90 110 130 fm r=1 fm r=1.5 fm r=2 fm r=2.5 reflux c o n v e r s io n 60 64 68 72 76 80 84 88 92 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 fmr=1 fmr=1.5 fmr=2 fmr=2.5 study of the performance of batch reactive distillation column ijcpe vol.9 no. 4 (2008) 32 effect of feed mole ratio figure (7) shows the conversion against feed mole ratio at batch time 90 minute and different reflux ratio. in the case of (0, 1) reflux ratio the conversion will increase when the mole ratio increase, because of the continues of with draw the desired product, the reaction is always to foreword and cause consumption of the limited component (acetic acid), and increase it is conversion. if reflux ratio is increase to (2, 3) the conversion will increase with mole ratio up to (2) after that the conversion will decrease with increase of the feed mole ratio. that is because of low percent of methanol in feed, not all acid will react, so the conversion is low. as the percent of methanol in the feed increase to a limited amount the conversion increase, then it will decrease because of reversible reaction will occur. fig.7: conversion of acetic acid vs. feed mole ratio at 90 minute and different reflux ratio. conclusions from the present work the following conclusions are made: 1the concentration of methyl acetate increase with increasing the reflux ratio to maximum value of reflux ratio equal (2) then decrease. 2the concentration of methyl acetate increase with decrease feed mole ratio. 3the concentration of methyl acetate increase with time to a limit value depending on the feed mole ratio. 4the higher concentration of methyl acetate in thee product was obtained at reflux ratio 2, feed mole ratio 1, and for batch time 60 minute. 5the conversion of acetic acid increase with feed mole ratio and reflux ratio to maximum value equal 2 then decrease. 6the conversion of acetic acid increase with time. 7the reactive distillation is more efficient than the conventional process at the best condition mentioned above for reactive distillation the conversion of acetic acid increase by 30.43% than that of conventional process, and the concentration of methyl acetate in the product increase by 75.14% than the conventional process. reference 1 barabosa d. and doherty, m. “the simple distillation of homogeneous reactive mixture”, chem. eng. sci., vol. 43, p. 541550, 1988. 2 isao, s., yagi, h., komatsu, h. and hirata, m. “calculation of multi component distillation accompanied by chemical reaction” jour. chem. eng. jap. vol.4, p26-33, 1971. 3 taylor r. and krishna, r. “modeling reactive distillation” chem. eng. sci., vol.55, p.5183-5229, 2000. 4 towler, g.p. and frey, s.j. (2000) reactive distillation, chapter 2 in reactive separation. 5 kai sundmacher “ modren methods in heterogeneous catalysis research” fritz haber institute, berlin, 14 november 2003. 7 victor h. agreda, lee r.u.s. patent 4435595 “reactive distillation process for the production of methyl acetate” 1984. 8doherty m.f., and m.f. malone “recent advances in reactive distillation” aiche annual meting, dallas, paper203c, november 3, 1999. feed mole ratio c o n v e rs io n 55 60 65 70 75 80 85 90 95 0.8 1.2 1.6 2.0 2.4 2.8 r=0 r=3 r=2 r=1 r= dr. cecilia k. haweel and taha m.a. hamza 33 ijcpe vol.9 no. 4 (2008) دراسة اداءعمود التقطير التفاعلي ٔانُظاو انًسحخذو ْٕ جفاعم انًٍثإَل يع حايض انخهٍك , جى دساسة انحقطٍش انحفاعهً رٔ انذفعات فً عًٕد رٔ حشٕات ٔجى اخحٍاس ْزا انحفاعم الٌ انحفاعم عكسً ٔدسخات انغهٍاٌ , الَحاج خالت انًثٍم ٔانًاء بٕخٕد حايض انكبشٌحٍك كعايم يساعذ . نهًٕاد انًحفاعهّ ٔانُاجدّ يحباعذِ انحفاعم نٕحذِ )جى انعًم بٓزا انُظاو بٕخٕد أ عذو ٔخٕد عًٕد انحقطٍش ٔجبٍٍ اٌ انحقطٍش انحفاعهً اكفأ يٍ انطشٌقّ انعادٌّ عهى ( 75.14% ٔ 30.43)%حٍث اٌ َسبّ انححٕل نحايض انخهٍك ٔانحشكٍض نخالت انًثٍم جضٌذ بًقذاس . (ٔانحقطٍش نٕحذِ . ( دقٍق90ّ ٔصيٍ 2 َٔسبّ انًٕاد انًحفاعهّ 2عُذ ساخع )انحٕانً عُذ افضم انظشٔف جى دساسّ جاثٍش انعذٌذ يٍ انًحغٍشات يُٓا َسبّ انشاخع َٔسب انًٕاد انًحفاعهّ ٔجاثٍش انضيٍ عهى اداء بشج انحقطٍش رٔ انذفعات انًصاحب نهحفاعم انكًٍٍأي خالل خشٌاٌ انسائم ٔانبخاس داخم انبشج ٔجاثٍشْا عهى جشكٍض انًٕاد انُاجدّ ٔجحٕل انًٕاد . انًحفاعهّ انُحائح انحً جى انحصٕل عهٍٓا نهخالئط انغٍش يثانٍّ ندٓاص انحقطٍش رٔ انذفعات انًصاحب نهحفاعم انكًٍٍأي كاَث َسبّ انححٕل . دقٍق90ّ ٔصيٍ 2 َٔسبّ انًٕاد انًحفاعهّ 2عُذيا جكٌٕ َسبّ انشاخع %90نحايض انخهٍك جسأي iraqi journal of chemical and petroleum engineering vol.18 no.3 (september 2017) 1 12 issn: 1997-4884 spatial data analysis for geostatistical modeling of petrophysical properties for mishrif formaiton, nasiriya oil field ameer talib, abdul aaali aldabaj* and ahmad a. ramadhan petroleum technology ,university of technology *ministry of oil/minister’s office abstract spatial data analysis is performed in order to remove the skewness, a measure of the asymmetry of the probablitiy distribution. it also improve the normality, a key concept of statistics from the concept of normal distribution “bell shape”, of the properties like improving the normality porosity, permeability and saturation which can be are visualized by using histograms. three steps of spatial analysis are involved here; exploratory data analysis, variogram analysis and finally distributing the properties by using geostatistical algorithms for the properties. mishrif formation (unit mb1) in nasiriya oil field was chosen to analyze and model the data for the first eight wells. the field is an anticline structure with northwestsoutheast general trend. mishrif formation is the important middle cretaceous carbonate formation in the stratigraphic column of southern iraq. the result of applying spatial data analysis showed the nature and quantitative summary of data and so it would be easy to remove the skewness and improve the normality of the petrophysical properties for suitable distribution by the algorithms. it also showed that unit mb1 in mishrif fromation contains good properties in which high porosity (0.182) and permeability (7.36 md) with low values of water saturation (0.285) that make it suitable for the accumulation of oil. key words: spatial data analysis, variogram, geostatistics introduction geoff bohling [1] declared that geostatistical algorithms give best results when input data are normally distributed and stationary where mean and variance do not vary in space. schlumberger [2] in its manual mentioned that data analysis process enables detailed analysis for both discrete and continuous properties through histograms and function windows, which visualize the distribution and correlation between these properties . holdaway [3] classified data analysis into two types, which work side by side: exploratory and confirmatory. the exploratory section visualizes the characteristics and nature of data to the statistician. on the other hand, confirmatory data analysis shows the quantitative deviation that used university of baghdad college of engineering iraqi journal of chemical and petroleum engineering spatial data analysis for geostatistical modeling of petrophysical properties for mishrif formaiton, nasiriya oil field 2 ijcpe vol.18 no.3 (sep. 2017) -available online at: www.iasj.net common statistical evidence of significance or confidence. ameer [4] performed three steps to complete data analysis; descriptive statistics in which it provides information about the nature of data, variogram analysis which defines the behavior of variation in a property and finally the spatial prediction using geostatistical algorithm. area of study amnah [5] mentioned that nasiriya oil field is located in thi-qar governorate about (38 km) north-west of nasiriya. it is an anticline structure with northwest-southeast general trend. many exploration wells had been drilled in the field and had discovered three reservoir (mishrif, yamama & nahr umr formations). atiaa, et. al [6] declared in their paper that the field is located in south of iraq between latitudes (34 80’ -34 60’) n and longitudes (57 50’ -60 10’) e, figure as shown in fig.(1). the mishrif formation is considered heterogeneous formation originally described as organic detrital limestones with beds of algal, rudist, and coralreef limestones, capped by limonitic fresh water limestones. jreou [7] mentioned that the studied formation is mishrif which is divided into two main units (upper mishrif, ma & lower mishrif, mb). they are separated by thin shale unit (about 10 m in thickness). the lower mishrif is subdivided into mb1 & mb2 with barrier rocks in some areas of the field. the hydrocarbon is concentrated in mb1 and unit mb21. the study is focused only on unit mb1. the thickness of unit mb1 in mishrif formation ranges from 53m to 70m for the first eight wells as given in table (1). descriptive statistics using histograms with quantitative summary or descriptive statistics can give precise information for formation data. histograms with their statistical summary for the properties in unit mb1 are discussed here. the total number of points in unit mb1 is 320. the minimum value of porosity is (0.0001) and the maximum one is (0.294). the average porosity is (0.182) which is less than the highest portion or the most frequent points in the distribution, mode. this reflects the shape of data which is negatively skewed (to the left) as shown in fig. (2a) and as given in table (2). water saturation in the unit is (o.022) as a minimum value and 1 (totally saturated) as as maximum value. the data of sw is positively skewed where the mode value is less than the average water saturation value (0.285) as shown in fig. (2) and as given in table (2). a large difference between the min. value (2.46 md) and the max. one (57 md) for the permeability unit mb1 with the range of (54 md). the average value of permeability is (7.36 md) as shown in fig. (2c) and as given in table (2). data transformation it can be noted from previous histograms that most of the petrophysical properties in the units are skewed. data transformation is applied to remove the skewness and improve the normality of data. box-cox transformation technique, available within data analysis in petrel package software, is applied to the petrophysical properties of the studied formation. ameer talib, dr.abdul aaali aldabaj* and dr.ahmad a. ramadhan -available online at: www.iasj.net ijcpe vol.18 no.3 (sep. 2017) 3 the power factor lambda (ƛ) represents the degree of skewness. lambda value for porosity data in unit mb1 is (1.6) as shown in fig.(3) while for water saturation it is (0.1) as shown in fig.(4). the permeability lambda value in this unit is (0.4) approaches to the square root transformation and as shown in fig.(5). fig.1, geographical location of nasiriya oil field [5] table 1, top of unit mb1 of mishrif fm. for the first eight wells (md, rtkb) well/unit top of mb1 (m) top of mb2 (m) thickness of mb1 (m) ns -1 2010 2063 53 ns -2 1991 2051 60 ns -3 2007 2063 56 ns -4 2000 2059.5 59.5 ns-5 1998 2057 59 ns-6 2006.5 2065.5 59.5 ns-7 1991 2058 67 ns-8 1985 2055 70 spatial data analysis for geostatistical modeling of petrophysical properties for mishrif formaiton, nasiriya oil field 4 ijcpe vol.18 no.3 (sep. 2017) -available online at: www.iasj.net table 2, statistical summary for unit mb property no. of points min. value max. value average st.dv. c.v phie (v/v) 320 0.0001 0.294 0.182 0.061 0.335 sw (fraction) 320 0.022 1 0.285 0.215 0.765 k (md) 320 2.45 57 7.36 8.79 1.19 (a) porosity (b) water saturation (c) permeability fig.2, petrophysical properties histograms for unit mb1 ameer talib, dr.abdul aaali aldabaj* and dr.ahmad a. ramadhan -available online at: www.iasj.net ijcpe vol.18 no.3 (sep. 2017) 5 fig.3, porosity transformation for unit mb1 fig.4, water saturation transformation for unit mb1 fig.5, permeability transformation for unit mb1 spatial data analysis for geostatistical modeling of petrophysical properties for mishrif formaiton, nasiriya oil field 6 ijcpe vol.18 no.3 (sep. 2017) -available online at: www.iasj.net variogram analysis variogram analysis is used to define the behavior of variation in a property where it is considered as a key parameter in many geostatistical algorithms. simply, a variogram is a plot of variability between semi variance (y-axis) versus separation distance (x-axis) in a specific direction two valuable steps are performed in analyzing variogram: 1determining the directions of the variogram, major, minor and vertical direction where each of them are perpendicular on the other. 2calculating the experimental variogram and then creating the variogram model based on the experimental one for each direction 2d variogram map defines the direction of sample points as shown in fig.(6). the major and minor directions of the variogram analysis are based on the 2d variogram map in which major direction is in 300 azimuthal angle while the minor one is 210 in azimuth (perpendicular on the major one) and as shown in fig.(7). schlumberger [2] mentioned in her petral software manual that the following parameters are also taken into consideration in order to analyze variogram: 1search radius: which is the maximum separation distance used in the search for sample pairs (no. of lags * lag distance). 2bandwidth: it is half the width of the search cone used as a cut-off to prevent the search area from becoming too wide at large separation distance. 3tolerance angle: it is the width angle measured from the search cone main axis. search cone parameters define the major and minor directions reflect directly on values of variogram ranges and as given in table (3). fig.6, 2d variogram map for mishrif formation ameer talib, dr.abdul aaali aldabaj* and dr.ahmad a. ramadhan -available online at: www.iasj.net ijcpe vol.18 no.3 (sep. 2017) 7 fig.7, major and minor direction based on 2d variogram map table 3, search cone parameters direction azimuth no.of lags lag distance search radius bandwidth tolerance angle major 300 8 2561 20488 6375 40 minor 210 8 1894 15152 8975 65 porosity variography exponential variogram model is applied for the behavior of the experimental variogram in the normalized porosity of unit mb1. the exponential behavior of this model makes a rapid variation at shorter distances (small lags) and it reaches the sill at asymptotic approach as shown in fig. (8). water saturation variography spherical model is used to represent the experimental variogram for the normalized water saturation of unit mb1. a linear behavior with a sharp transition to a flat sill are characterized in this model behavior as shown in fig. (9). permeability variography the behavior of the experimental variogram for the normalized permeability is similar to that in porosity so that the exponential model is chosen as shown in fig.(10).variogram computation for the petrophysical properties for unit mb1 are resulted from the analysis of search cone parameters that reflect the shape of variogram analysis as given in table (4). property modelling it is the process of filling grid cell with discrete and continuous properties in which the layer geometry in the grid follows the geological layering in the model area. the purpose of property modeling is to make it possible to distribute different properties among the wells after performing data analysis. sequential gaussian simulation (sgs) modeled all the continuous properties of porosity, water saturation & permeability and as shown in fig. (11), 12) & (13), respectively. the distribution was done by depending on variogram analysis parameters and as given before in table (3). spatial data analysis for geostatistical modeling of petrophysical properties for mishrif formaiton, nasiriya oil field 8 ijcpe vol.18 no.3 (sep. 2017) -available online at: www.iasj.net table 4, summary of the variogram parameters for the petrophysical properties of unit mb1 property sill nugget major range (m) minor range (m) vertical range (m) phie 0.964 0 8596.4 5000 13 sw 0.96 0 2559 1892 4 k 0.96 0 8158 5040 16.2 fig.8, exponential variogram for porosity in unit mb1 ameer talib, dr.abdul aaali aldabaj* and dr.ahmad a. ramadhan -available online at: www.iasj.net ijcpe vol.18 no.3 (sep. 2017) 9 fig.9, exponential variogram for water saturation in unit mb1 spatial data analysis for geostatistical modeling of petrophysical properties for mishrif formaiton, nasiriya oil field 10 ijcpe vol.18 no.3 (sep. 2017) -available online at: www.iasj.net fig.10, exponential variogram for permeability in unit mb1 fig.11, porosity distribution with variogram analysis dependent in unit mb1 ameer talib, dr.abdul aaali aldabaj* and dr.ahmad a. ramadhan -available online at: www.iasj.net ijcpe vol.18 no.3 (sep. 2017) 11 fig.12, water saturation distribution with variogram analysis dependent in unit mb1 fig.13, permeability distribution with variogram analysis dependent in unit mb1 conclusion it can be concluded from applying spatial data analysis in mishrif formation, nasiriya oil field that the nature and quantitative summary of data can be visualized and so it would be easy to remove the skewness and improve the normality of the petrophysical properties for suitable distribution by the available algorithms. the statistical average values of porosity (0.182), water saturation (0.285) and permeability (7.36 md) in unit mb1 of mishrif fromation reflect the the high quality of reservoir properties. also, the distribution of porosity, water saturation and permeability as shown in fig.11,12 & 13, respectively support this conclusion. references 1geoff bohling, 2007 “introduction to geostatistics in hydro geophysics: theory, methods, and modeling”, boise state university, boise, idaho. 2schlumberger, 2013 “petrel technical manual”,. 3holdaway, k.r.”exploratory data analysis in reservoir characterization projects”, spe 125368,200. 4hameed, a.t,2016. "geostatistical approach of petrophysical spatial data analysis for geostatistical modeling of petrophysical properties for mishrif formaiton, nasiriya oil field 12 ijcpe vol.18 no.3 (sep. 2017) -available online at: www.iasj.net properties distribution for mishrif formation in nasiriya oil field" m.sc. thesis, petroleum technology , university of technology, 5handhel, a.m. , 2006 " reservoir properties study for mishrif formation in nasiriya oil file & their relation with oil production", thesis, department of geology, university of basrah. (in arabic). 6atiaa & amnah m. handhel “a fuzzy logic approach in infer reservoir permeability from depth and porosity measurements for mishrif limestone formation at nasiriya oil field, south of iraq”, college of science, university of basrah,issn:1991-8941. 7jreou, g. , 2013” a preliminary study to evaluate mishrif carbonate reservoir of nasiriya oil field", college of engineering, university of kufa, 136305-0808ijens. iraqi journal of chemical and petroleum engineering vol.15 no.1 (march 2014) 5963 issn: 1997-4884 design of horizontal well program for ajeel field mohammed s.al-jawad, a.a.al-dabaj * and hassan abdul hadi abdul hussien university of baghdad-college of engineering-petroleum engineering department * reservoirs directorate-ministry of oil abstract horizontal wells are of great interest to the petroleum industry today because they provide an attractive means for improving both production rate and recovery efficiency. the great improvements in drilling technology make it possible to drill horizontal wells with complex trajectories and extended for significant depths. the aim of this paper is to present the design aspects of horizontal well. well design aspects include selection of bit and casing sizes, detection of setting depths and drilling fluid density, casing, hydraulics, well profile, and construction of drillstring simulator. an iraqi oil field (ajeel field) is selected for designing horizontal well to increase the productivity. short radius horizontal well is suggested for the developing the field since many drilled vertical wells are exists a soft string model was programmed to predict the imposed loads on suggested drillstring. six operating conditions of drillstring includes rotating off bottom, pick up without rotation, slack off without rotation, pick up with rotation, slack off with rotation, and sliding ,were considered. also, two buckling modes of drill string were estimated. according to drillstring simulator results, short radius well of build rate 90 deg/100 ft could be implemented without exceeding the strength limits of the suggested drillstring. keywords: petroleum; horizontal drilling; design well introduction to meet the increasing demand of petroleum resources, since 1970's the horizontal well drilling technology has been improved festally. now this technology has become the important technical way to enhance oil recovery of old wells [1]. ajeel field is located about 30 km to the north east of tikrit city, north iraq. the average elevation of the field area is 150-170 m above mean sea level. the reservoir structure consists of the main (southern) dome and north west dome. the main structure contains an oil accumulation mainly in the jeribe, dhiban, euphrates, serikagni, and favreina formations, and a gas cap mainly in transition beds. all these units contain carbonated rocks with quite poor permeability [2]. in 1996 horwell company examined for n.o.c the possibility to apply horizontal well technology on the field to increase its productivity. five main formations were selected to perform the study, which are t12-t15, jeribe, dhiban, euphrates, and favreina. due to the proximity of gas and/or water contacts in some critical iraqi journal of chemical and petroleum engineering university of baghdad college of engineering design of horizontal well program for ajeel field 60 ijcpe vol.15 no.1 (march 2014) -available online at: www.iasj.net areas and low permeability in other, the company suggested three locations for horizontal drilling which are jeribe, euphrates, and favreina. with aid of analytical calculation and correlation issued from basic numerical simulation, high horizontal well productivity indexes were obtained ranged from 6 up to 14 for replacement ratio from 2.75 to 6.5 [3]. steps of design 1bit and casing sizes horwell [3] study suggested hole size of about 8.5 in for horizontal well. if the production casing or liner size was chooses as 6 5/8in, the sizes of bits to drill the whole well and casing sizes for casing the well could be determined with api tables. table 1 provides the final sizes of bits and casing strings. 2setting depths and drilling fluid densities pore and fracture pressures data of the ajeel field were gathered from offset well reports (geologic reports). table 2 shows these values of pressures at different depths. with these data, casing setting depths and drilling fluid densities were determined with liner interpolation method. since the depth of euphrates formation is nearly 2975 ft (setting depth of the production casing), table 3 provides setting depths of other casing strings and required density for drilling these sections. 3casing grads casing grads and weights were determined for each section based on the density of drilling mud and formation pressures of the field. a worst conditions design were considered in computing of tension, burst, collapse, and bending loads imposed on casing string [4]. also safety factors with high values for each type of load were assumed. for tension (sf=2), for burst (sf=1.2), and for collapse (sf=1.2) .with the aid of computer program, the detailed information about the casing program was provided in table 4. 4well profile ajeel oil field has many vertical wells with known depths. these vertical wells could be converted to short radius wells (reentry wells) by drilling building section with a high build rate of angle. usually, this type of horizontal well could be completed as open hole, since the formation is limestone. well profile was constructed with radius of curvature method (most common method for profile design) as single curve with the following equations [5]. r= 5727.27/ bur …(1) v1= r.(sini2-sini1) …(2) h1=r.(cosi1-cosi2) …(3) l1=100.(i2-i1)/bur …(4) figure 1 depicts single build (constant build) horizontal well profile suggested for this field when the rate of build is 90 deg/100ft. table 5 presents the dimensions of this profile (short radius well profile). a 63.66 ft vertical distance is required to convert the well from vertical to horizontal. while vertical depth of about 2934 ft is required to start the deflection process. fig. 1, horizontal well profile mohammed s.al-jawad, a.a.al-dabaj and hassan abdul hadi abdul hussien -available online at: www.iasj.net ijcpe vol.15 no.1 (march 2014) 61 5drillstring loads drill string loads (drag & torque) were calculated with soft-string model [6]. the equations of this model are: fn=[(t ∆φ sin θavg) 2 +( t ∆θ + w sin θavg) 2 ] …(5) ∆t=w cos θavg±ƒfn …(6) ∆m= ƒ fnr …(7) ff= ƒ fn …(8) six operating parameters (pick-up without rotation, slack-off without rotation, sliding, pick with rotation, slack-off with rotation, drilling with rotation) are considered in the computation [7]. friction coefficients between drillstring and wall of the hole are derived from the type of mud [8].also; buckling tendencies (sinusoidal and helical buckling) of drillstring are calculated from the following equations [9]: 5.0 sin 2        r gaei f s cir  …(9) r eiw f 83.2 *  …(10) figure 2 shows the loads analysis of inverted drillstring using drillpipe type(s-135) and drillcollar without rotation. while figure 3 shows the string loads for rotating case. fig. 2, drillstring loads without rotation fig. 3, drillstring loads with rotation in both cases, a maximum surface tension of the string was recorded in pick-up condition. these values are smaller than the tensile strength of drillpipe (388000 lb), which provided reasonable safety margin. also, maximum compressive load has been achieved when using steerable bottom hole assembly (sliding mode). this mode of drilling could be used safely since the sinusoidal critical buckling of drillpipe (40000 lb) is larger than the compressive load in the string. in addition, a sufficient surface slack-off load is noticed which provided adequate string weight to offset the axial friction effects while tripping in the hole. 6hydrulic requirements a computer program was constructed to calculate the pressure losses in the circulation system for bingham plastic fluid (since the offset wells are drilled with bingham plastic mud). also nozzles size, jet velocity, hydraulic power at the bit (bhhp), and impact force of the bit (bif) were calculated. table 6 provides the results of calculations. conclusions this paper is concerned with the design of horizontal well aspects. these included selection of bit and casing size, setting depths and drilling -150000 -100000 -50000 0 50000 100000 150000 200000 0 500 1000 1500 2000 2500 3000 3500 4000 measured depth,ft d r il ls t r in g t e n s io n ,l b sinusoidal buckling helical bukling pick up w/o rotation slack off w/o rotation sliding -100000 -50000 0 50000 100000 150000 0 500 1000 1500 2000 2500 3000 3500 4000 measured depth,ft d r il ls tr in g t e n s io n ,l b sinusoidal buckling helical buckling pick up w/rotation slack-off w/rotation drilling w/rotation design of horizontal well program for ajeel field 62 ijcpe vol.15 no.1 (march 2014) -available online at: www.iasj.net fluid densities, well profile, drillstring loads and casing. an iraqi oil field which is (ajeel field) is selected for application this design. from the obtained results, a vertical well could be converted to short radius well with 64 ft vertical distance needed. also, a single build profile with rate of build of about 90 deg/100ft could be implemented without exceeding the strength limits of the inverted drillstring. nomenclature θ: inclination angle at the lower end of element, degree. φ: azimuth angle at lower end of element, degree. θ: hole angle, measured from vertical, deg ρ: weight per cubic inch, lbm. ƒ: coefficient of friction. ∆t: change of axial tension over the length of element, lbf. ∆m: change of torsion over the length of element, ft-lbf. ∆θ: change of inclination angle over the length of element, degree. ∆ф: change of azimuth angle over the length of element, degree as: crosssectional area of pipe,in 2 bur:build up rate of angle ,deg/100ft e: young's modulus, psi fcrit: critical buckling force ,lbf fn: the net normal force, lbf ff: sliding friction force acting on the element, lbf. f * : helical buckling force, lb g: gravitational force, lbf . h1: horizontal displacement of build section, ft i1, i2: inclination at station 1and 2, degree i: moment of inertia of pipe, in 4 l1: length of build section, ft m: torsion at the lower end of element, ft-lbf. r: radius of curvature, ft r: characteristic radius of element, ft. t: axial tension at the lower end of the element, lbf. v1: vertical height of upper build section, ft w: buoyed weight of drillstring element, lbf. references 1economides, m.j., watters, l.t., and norman, s.d., "petroleum well construction", john willey& sons ltd, england, (1998). 2hassan, a., aljawad, m., and aldabaj, a., "design of horizontal well programm for an iraqi oil field"; ph.d. dissertation, university of baghdad, 2010. 3horwell, "horizontal drain opportunities for ajeel field", december, (1996). 4rabia, h., "oil well drilling engineering principles & practice", graham & trotman limited, london, (1985). 5rabia, h." well engineering & constructions", (2005). 6johancsik, c.a., friesen, d.b., and dawson, r., "torque and drag in directional wells-prediction and measurement", jpt, (june 1984), 987-992. 7cobert, k.t., and dawson, r., "drillstring design for directional wells", ogj. (apr30, 1984), 61-66. 8dellinger, t.b., gravley, w., and tolle, s.c.," directional technology will extended drilling reach", ogj. (sept. 1980), 153169. 9dawson, r. and pasaly, p.r., "drillpipe buckling in inclined holes", jpt, (oct.1984), 17341738. mohammed s.al-jawad, a.a.al-dabaj and hassan abdul hadi abdul hussien -available online at: www.iasj.net ijcpe vol.15 no.1 (march 2014) 63 table 1, bit and casing sizes for 6 5/8 in production casing bit size, in casing size ,in 17 1/2 13 3/8 12 1/4 9 5/8 8 1/2 6 5/8 . table 2, pore and fracture pressure data depth(rtkb) ft pore pressure psi fracture pressure psi 2261 1518 2057 2404 1572 2212 2562 1487 2383 2747 1492 2637 table 3, setting depths and drilling mud densities setting depth ,ft mud density, ppg 1445 8.92 2520 12.63 2975 11.77 table 4, casing grads and weights hole size in casing size in grade weight lb/ft length ft 17.5 13 3/8 k-55 54.5 1445 12.25 9 5/8 k-55 36 2520 8.5 6 5/8 n-80 26 2975 table 5, dimensions of horizontal well profile radius of curvature, ft 63.66 vertical depth of build section, ft 63.66 horizontal length of build section, ft 63.66 length of build section, ft 100 kick-off point(kop),ft 2934 total measured depth, ft 3534 table 6, hydraulic calculation of circulation system dh in q gpm ps psi pstring psi pannulus psi pbit psi an in 2 vn ft/sec dn, 1/32in bhhb hp bif lbf 17.5 12.25 8.5 692 510 310 50 38 22 412 403 250 42 73 94 2525 2555 2703 0.39 0.34 0.24 561 474 505 13.1 12.2 10.29 1018 758 602 1789 1577 1179 ijcpe vol.9 no.1 (march 2008) 31 iraqi journal of chemical and petroleum engineering vol.9 no.1 (march 2008) 31-34 issn: 1997-4884 experimental studies on the benification of fine solids by forth flotation muna yousif abdul-ahad environmental engineering department college of engineering university of baghdad – iraq abstract in this paper, the experiments were carried out in laboratory flotation cell treating solid fines. the effect of variables such as collector oil dosage, pine oil dosage and solid content of the feed slurry have been investigated on the flotation characteristics of low rank coal. attempts have also been made to develop some empirical eq. to predict the yield and ash content of concentrate with the operating variables, solids concentration, collector oil dosage, and pine oil dosage, to estimate the recovery at any operating conditions. the calculated results obtained from regression equation by correlating the variables with the yield and ash content of concentrate have been compared to study whether calculated values match closely with the experimental values by using f test at any level of significance. keywords: flotation, solid fines treatment by flotation. introduction it has been reported in the literature, biswal et. al. (1), lynch et. al. (2), trahar (3), vanagamudi and rao (4), and warren (5) that the particles reach the froth phase or concentrate either by true flotation or by entrainment. true flotation occurs when the floatable particles colloid with the bubbles, attach with them and the resultant mineralized bubbles rise towards the froth level and are then scraped off. entrainment biswal et al(1),lynch et al (2), trahar (3) warren(5) when non-floatable particles enter in the water present in between the spaces of the bubbles and continue to move upwards. during the traverse, large particles drop back to the pulp phase becomes of higher mass, whereas, fine gangue continues to move and ultimately reports to the froth vanagamudi and rao (4). hence, entrainment is non-selective and has determinal effect on flotation. warren(5) found that in a batch flotation, the recovery of floatable mineral at a particular interval of time is linearly related to the weight of water recovered in a system in which experiments are carried out by varying the height of froth coloumn, rate and depth of froth removed. froth flotation is the oldest physical separation type and has the advantages of relatively low power consumption per unit mass of material processed and a proven capacity to handle higher tonnage rates of solids, than the newer oil agglomeration procedures. the obvious disadvantages of froth flotation are its tendency to entrain very fine materials and the production of a wet froth. both effects can potentially be reduced by a cleaner float using a hydrocarbon entrainer, but first it is necessary to establish the best performance of the roughing float. low rank coals have a high volatile content and a high h/c ratio. a demineralized low-rank coal would thus appear to be an excellent feed-stock for liquefactions, combustion, and of several possible uses would be as the solid component in a coal-oil mixture. in this paper a mathematical approach based on correlations between variables affecting flotation process for the yield of concentrate (y) and ash content of concentrate (a) respectively using multiple linear regression kennedy&neville (6),francis(7), klugh (8), & mohrotra & saxena (9). university of baghdad college of engineering iraqi journal of chemical and petroleum engineering experimental studies on the benification of fine solids by forth flotation ijcpe vol.9 no.1 (march 2008) 32 correlation between variables and yield of concentrate: the process parameters can be correlated with the yield of concentrate by an equation of the form: y=k0 (x1) k1 (x2) k 2 (x3) k 3 (1) correlation between variables and ash content of concentrate: a= j0 (x1) j 1 (x2) j 2 (x3) j 3 (2) (2) where (y) represents yield% of concentrate, (a) represents ash% content of the concentrate, and x1, x2, and x3 represent solids concentration, collector oil dosage (kg/t) and pine oil dosage (kg/t) respectively. the constants k0, k1, k2, k3, j0, j1, j2 & j3, are evaluated from the principle of multiple linear least squares regression analysis, for which statistica program package is used for any number of constants present in regression eq. using the experimental data. the prediction of concentrate yield%, and ash% can be made for any given value of solid concentrate, collector oil dosage and pine oil dosage respectively within the experimental limit. fisher ' s f-test kennedy & neville (6), francis (7) & klugh (8) is used to see how the predicted eq. of the concentrate yield, and ash are fitted to the experimental values. the statistic f is given by: f= 2 2 y x s s (3) where 2 11 2 )( )1( 1 1 xx n s n i ix      (4) ).....( 1 11 1 n xx n x  (5) 2 12 2 )( )1( 1 2 yy n s n j jy      (6) ).....( 1 11 2 n yy n y  (7) after f is found for yield of concentrate, and ash. the tabulated value of f for 5% level of significance and degrees of freedom d.f., f1 and f2 is fp. where f1 = number of observations (n1-1) f2 = number of observations (n2-1) fp =tabulated value of f thus if f<fp, then it shows a good agreement between the experimental and calculated values of yield of concentrate and calculated values of ash content of concentrate. experimental work coal as a product of degradation of vegetable matter was prepared. the liberation size of ash in the coal was estimated at around below 100 microns and classified using standard test sieves. the size and ash distribution of sample used in these studies are given in table 1. table 1 size analysis of sample ash% weight% size, microns 35.45 28.3 -100+75 40.58 22.8 -75+45 50.70 48.9 -45 42.24 100.0 total the flotation tests were carried out in a batch laboratory flotation system as shown below: fig. 1 experimental setup the flotation cell of 2.5 l capacity using the conditions: (1) mixing time for preparation of slurry =3min, (2) conditioning time =5 min, (3) impeller speed =1400 rpm, and (4) time of collection = 90 sec. the pulp was conditioned with diesel oil (collector) for 5 min and after conditioning, pine oil (frother) was added at appropriate dose and solids concentration was maintained by adding required quantity of water. then, aeration was started by operating the air valve at a pressure of 400 kpa and the froth floated concentrate was collected for 90s .the concentrate and tailings were then dewatered, dried, weighed, subsampled and ash content of each sample was determined. all the tests were carried out using the above procedure by varying operating conditions (table 2). muna yousif abdul-ahad ijcpe vol.9 no.1 (march 2008) 33 table 2 operating conditions of the variables. operating conditions of variables sl.no fixed operating conditions pine oil dosage kg/t collector dosage kg/t solids concentration % 1.0 2.0 _ solids concentration% (10,15,20,25) 1 1.0 _ 25 collector oil dosage kg/t (0.5,1.0,1.5,2.0) 2 _ 2.0 25 pine oil dosage kg/t (0.15,0.5,0.75,1.0) 3 table 3 comparison of experimental and predicted values of the test data. operating variable sl. no predicted experimental cleans tails cleans as h % yie ld % ash % yie ld % as h % yiel d % 20. 13 35. 56 45.0 0 70. 55 20. 55 35.5 5 10. 00 solid concentratio n % collector oil dosage kg/t pine oil dosage kg/t 1. 30. 24 40. 42 50.0 0 67 .00 30. 55 40.5 5 15. 00 28. 67 45. 36 50.5 5 55. 55 28. 00 45.0 0 20. 00 25. 02 38. 06 48.5 0 65 .5 5 25. 00 38.0 0 25. 00 21. 89 26. 00 43.7 8 72. 87 20. 53 27.5 5 0.5 0 2. 26. 00 35. 15 49.1 0 70. 15 26. 55 30.8 3 1.0 0 27. 10 37. 05 50.0 1 59. 86 24. 57 42.1 5 1.5 0 26. 00 41. 08 48.9 6 63. 11 27. 36 35.8 2 2.0 0 24. 00 31. 05 48.0 0 70. 13 20. 97 29.8 4 0.1 5 3. 26. 09 36. 00 51.0 3 68. 01 25. 03 34.1 0 0.5 0 23. 98 26. 75 38. 01 36. 98 50.0 0 49.0 0 58. 99 58. 95 27. 10 27. 00 41.0 8 47.0 3 0.7 5 1.0 0 results and discussion the regression equations using the experimental data given in table 3 were applied for the correlations assumed above in eq. 1 and 2 respectively to evaluate the constants for the concentrate yield% and ash content% of concentrate. fisher’s f-tests were used to see how eq. 1 and 2 were fitted to the experimental values as follows: the relation between concentrate yield and the variables reduces to: y= 23.002 (x1) 0.130 (x2) 0.330 (x3) 0.120 (8) a graphical representation for the experimental and predicted values of the test data for different solid concentration% collector oil dosage kg/t are shown in fig. 2 to 4. the statistic f is calculated as 1.104 for yield of concentrate. the tabulated value of f for 5% level of significance and degree of freedom d.f. =11 and f2 =11 is fp =3. in this case also f< fp results in a good agreement between the experimental and calculated values of yield of concentrate given in table 3. 20 30 40 50 60 70 80 5 10 15 20 25 30 solid concentration% e x p e ri m e n ta l a n d p re d ic te d v a lu e s o f y ie ld % a n d a s h % experimental cleans yield% experimental cleans ash% experimental tails yield% experimental tails ash% predicted cleans yield% predicted cleans ash% fig. 2 experimental and predicted values of the test data for different solid concentrations% experimental studies on the benification of fine solids by forth flotation ijcpe vol.9 no.1 (march 2008) 34 20 30 40 50 60 70 80 0 0.5 1 1.5 2 2.5 collector oil dosage kg/t e x p e ri m e n ta l a n d p re d ic te d v a lu e s f o r c le a n s a n d t a il s o f y ie ld % a n d a s h % experimental cleans yield% experimental cleans ash% experimental tails yield% experimental tails ash% predicted cleans yield% predicted cleans ash% fig. 3 experimental and predicted values of the test data for different collector oil dosages kg/t 20 30 40 50 60 70 80 0 0.2 0.4 0.6 0.8 1 1.2 pine oil dosage kg/t e x p e ri m e n ta l a n d p re d ic te d v a lu e s o f y ie ld % a n d a s h % experimental cleans yield% experimental cleans ash% experimental tails yield% experimental tails ash% predicted cleans yield% predicted cleans ash% fig. 4 experimental and predicted values of the test data for different pine oil dosages kg/t the relation between concentrate yield and the variables reduces to: a=18.983 (x1) 0.101 (x2) 0.120 (x3) 0.100 (9) the standard deviation of the percent errors in the equation above is 0.054 the statistic f is calculated as 0.987 for ash content of concentrate. the tabulated value of f for 5% level of significance and degree of freedom d.f. =11 and f2 =11 is fp =3. in this case also f< fp results in a good agreement between the experimental and calculated values of yield of concentrate given in table 3. the graphical representations of experimental and predicted values of the test data are shown in fig. 2 to 4. conclusions it may be concluded that when the experimental data were correlated with the operating variables through a regression equation then the estimated regression equation was found to fit within experimental limits and the same was tested and verified by using fishers ftest at 5% level of significance. references 1. s.k.biswal, p.s.r. reddy, and s.k. bhaumik,” some aspects on entrainment in coal flotation.” the indian mining and engineering journal, vol.41. no. 5, may 2002, p 39. 2. a.j.lynch, n.w.johnson, e.v.manlaping and c.g.thorne,”mineral and coal flotation circuits and their simulation.” elsevier scientific publishing co., amsterdam, 1981. 3. w.j. trahar,”a rational interpolation of role of particle size in flotation.” international journal of mineral processing, vol.8, 1981, p289. 4. m.vanagamudi and t.c.rao,”a model for the prediction of fines recovery in batch coal flotation.” mineral engineering vol.2, 1989, p185. 5. l.j.warren,”determination of the contributions of true flotation and entrainment in batch flotation tests.” international journal of mineral processing, vol. 14, 1985, p33. 6. j. b. kennedy & a. m. neville, "basic statistical methods for engineers & scientists", 2nd edition, crowell, 1976. 7. a.francis, "advanced level statistics", st (p) l to, 1979. 8. h. e. klugh, "statistics: he essentials for research", 2nd edition, wiley, 1974. 9. s. p. mehrotra & a. k. saxena, “studies on froth flotation of coal”, int. j. miner. processes, 10 (1983) 255. i n, c., '', fiist o p s . l ' . i n d . t ) . , . s e r . , i n n d d r o p 3 5 , 2 4 1 m . s c . ( 2 0 0 4 ) , t 5 , i i , "drop a w l l i l l iigpti r a q i j o u r n a l o f c h e m i c a l a n d p e i r o l e u m e n g n e e r i n gv o l . 8 n o . 1 ( m a r c h 2 0 0 7 ) 4 3 4 s e f f e c t o j s i n t e r i n g t e m p e r a t u r e a n d s o a k i n g t i m e o n t h e p h y s i c a l and dielectric properties of batio3 for different baiti ratios a m e l s . m e r z a ' a n d k h a l i d f . c h a s i b t ' ,. ' m;nb.r) at scj. ? aaa i e. haotog hoq ( i n i . a ! l 4 * r e ' i , c d e p | ! t 4 t 4 ! l n i v e t s , d o t t e ( h a o t a g h a q abstract ...::,i::.i,:l:1,,! *'*::''hcr kc ihip,o\lnent afphrsicat dnd.tietectric prope ies afbariot cercnic nlate,itrt by :,.,:::., ii,!,:.':, ,i! ,,*,".,r,.o, a. bacot. rh. p,eparcd *nptes sinterect at .lifferent tenperanws a,d yalyths sodkrjg !t::n:.,1,!c,tc'.,t,: \h.aw,th, ihcrtn.\tns t.he \i:tletih8 tetnpetuturc ||hhin t35aac and soakins ti"rc af to nri gi"" !,"ui ;nttrtcot dnd physicat ptopctll.s, wh(h indt.dte !he rcactiok is conplete at higher renperalure ana parrca. j(ulralrft: sintering,soaking, bariunr tiranate. introduction piezoelectficity is one property ofa group ofdielectrjc matciais called feroelectrics. these marc ars are cfiaracterizcd by a domain strucrure that can bc nrodified by an electric field. the piezoelectric efiect nranjfests as a sponlaneous potential difference across the opposite fac€s of a volume of nraterial when under an applied stfess. this potential is proportional directly to the mechanical stress applied to it. the inverse is also true, i . e . , a p p l i c a t i o n o f a n e l e c t f i c f i e l d c a u s e s s r r a r n r n a v o l u r n e o f p i e z o c l e c t r i c m a t e r i a l i i l'l he fin! piczoelectric nraiciial discovcred was c . r l c i u i r f i r : i r ) . u c . w i i c h f " , r t . e p e r o r . k i r e s r u ( r l r c ^ u j d i l i o r . i l o n r t | e r c r a l e \ r r r p l e i s e d r . u r l r i u n i t e . w h i , 1 rs comnro ly used in capacitors and lransducefs due ro its high pennittivity 12l. the reacrion behveen baco3 and tio, proceeds via several internrediate staces of which f o n a l i o n o f b a t i o ! h t h e n r o s t d i s t i n c r . t h e g . u , n , , , " o f b a t i o r c c r j r n c j s ( o r r t o l l c d b y h b i r : o n t h e g r " i n g r 0 $ t t r b y r i n g . i c \ l l r ( ! . r o r . . o . l j o . h a , c c o n d p h a s e w h i c h b e h a v e s a s i n h i b i l o r [ 3 ] . t t r e s t o i c h i o m e t r i c powdeg can be oblaincd by adjusting the ba/ti ratio, where dre higher atti ratio leads lo the irrcorporation of excess bariunr in rhe powdcr [4]. it is extecled rhat o p t i m u n ] s i n i c f i n g b e h a v i o r a n d e t e c t r i c p r o p e f i i e s a r e o b t a i n e d , w i t h s t o i c h i o m e t r y r a n g e 0 . 9 9 j i . 0 0 j j l . experimental work the piezoceramic mare al barilrm riranlte (batioj) was lrepared by the r€action of a suitable grade of baco3 with tio,. these raw marerials are weighed out i n j o , r r d r l f e r e n r r a t : o s ' 1 . 0 3 t . i l . i 1 . 0 j . i t . 0 0 l l r c c o r d i n g i o t h e s t o i c h o m e t r i c e q l r c l i o n b e l o w : baco3 + tio? -,) batior + co? (l) fof each run the raw materials mixed and lnilted in an agate ball mill for 8 hrs and rhen calcined rne resutr powder at i200oc for 8 h.s. t h e c a l c i n e d p o w d e r m i l l e d a n d s i e v e d i n a n 3 8 l n r < i e r e . r f e r r w e i g h e d a p r o p e r a n o u | l t 1 d p r e \ , i t i n l l n ' x j r g q : h p v a b i n d e r , i c r o d w i r h i c r n j j a m e r e r us'ng 2.5 ion load. these samples thcn sintered in air at differcnt temperatures (1200, i300, 1350.c) ior differen! p e r j o d s ( 2 , , 1 , 6 , 8 , i 0 h f s ) . t h e b u l k d e n s i r y n e a s u r e d and the trlre porosity is calclrlated by dre relarioh. ,,,,, ,,,,,1 ay'"* i el t,tptes4area dta : .4f':/ r. drra\\j s : r ( e r \ e d e n . i t ] o l w a l e r e q u d l l o i g . m . r t e r . r , , , r.r"" -lt !!!!!! !! rc. (jj l true.tehsity l i j c p e v o l . 8 n o . 1 ( m a r c h 2 0 0 7 ) 4 3 ejj,ct afsnikting letrdetuhtrc an.l soaki|1g l't! an thephrsicat ahd dictechic pt'openies afbatntfat aij|uent bdtirdtias the trlre density for batior is 6 02 g cn!3 l5l and the rclative dielectric constant (k) may be measuled by usrng lcr eter for the elecnoded samplesl ( 3 ) f i : l d l l \ d c ' ] i b o i n i o l r . ] p l e ' ) i n r ' r e j r l differcnt te pemtufcs with ba/ti = 0 997 : ; ; 6 r i g . i r c c e n r a g r r j e p o f o i r ) o f b d l i o a m " l c . , n l i r r d , r d i " f e r e r r r e n p e r a l j f e ' w r r b i i i n a o ' i i a j b j l l d c n s i l ) o f b r t r o r s r m p l c a s i l c r e d a t d f i e r c n t t e n l p e f r l u r e s w i l h b a ' t i = l 0 l t i g . d p e r c e n r a g e i u e d o o s i r ) o i b " , i o r s a n p e q , l r r r c r e d a r d i f r e i e ' r | r e n p e r a r ' r r c s $ i r h b a n i = l 0 l i t iwh€re c is the capacitance of the prepared samples (in f r r i d j , d i i r i . l r e ' o f l l . c s r m p l e ' i n n \ ' c o i ' l l c n . i i i ' i ' i ' ' , ) o r ' * * ' " 8 8 5 ' l 0 ' 1 2 c : n n l o r d a i ' ihe cross-sectional area of sanrples (nt results and discussion bulk density results shows that $e sinlering tenrpcraturc and soakjng timc has a remarkable influence on the bulk d€dsity of the dredared batior for the two ba,iti ratio's as sho$n in fig' i. and rie. 3. above 1300"c sintering cal$es dhcontinuous er"i,' noi'1h ly i.rcrea"ed drftsior in l|e liqjid phrse a i . r . , u " : o f o ' t i . r " , l c o r p o l ' r d ' a r e p o , s i b l e $ : r ' \ c i l h e r exccss of tior or bacor' under the condition oi excess r i l a r . . . . a l i a r ' d r \ d ' e i c f o r r n c d r o e r h t r r c e ' i n l c r i n b r r r d l h i s t r . . . u c e r . r c p o r r i a e x p c ' ' m e n r " l d i r r i s l ' n d f r g l [ j ] i ' ' i ! . " : \ 3 i .t : t ! fis. 5 dielectric constant (measlrred at l0 khz) as a funition soaking tinre for batior with baiti= 0 99? true pofosity porositv for the siniere'l batior with different s : n l e r i n c i . n o e r o r u r e a n d , o a l ' i n g l i m e f o r l h e n \ o c a r e ( o f b a i i r o o o r , l . 0 l l $ d " . d l c l l e d i r l h e p e r c e r t a g e hj;t;c'-i;; i;"'6 or barior (6.02 gn/cm3l and plotted in fig. 2 and fig 4 i j c p e v o l . b n o 1 ( m a r c h 2 0 0 7 ) athels. mer.a and khalid f. chdsib mples = 1 . 0 3 i -r-l : _ . l l r ) " . ;= 0.991 ' . . ' . ' references l hsiao-lin, wang "structure and dielectric properties ofperovskile barium titanare" december 04, 2002. 2.theodore, m. h., jules, m., & roberl, j.l., j. am. c € r a m . s o c . , 4 9 [ 6 ] 2 9 5 ( 1 9 6 6 ) . 3 . p a s c a l , p . , c h r i s t i a n , c . , a n n e , l . , & a m . c e r a m . s o c . , 8 2 u l l , ( 1 9 9 9 ) . 4 . m y u n g , c . k . , d o h , y . k . , & n o n g , ceram. soc. 83 [2] december (2000). 5 . l l l a v a c j . , " t h e t e c h n o l o g y o f c l a s s a n d c c f a n i c s ' , e l s e v i e r s c i e n t i f i c p l r b l j s h i n g c o m p a n y , ( 1 9 8 3 ) . i b e r n a r d , t . . j . m . h . , j . a m . fig 6 dielectric constadt (measured at l0 khz) as a irnclion soaking time for bati03 with btti = 1.03 trrelectric constant dielectric constant of batior is extremely sensitive to 3ati ratio, sintering temperature, and soaking period as i : o w n i n f i g . 5 a n d f i g . 6 , i n w h i c h t h e d i e l e c r r i c ionslant irrcreased as the sintering temperarure increased, :: reaches a maximum value at l350oc at 8-10 hrs, and it :iff€rs slighlly afler this remperature. conclusions : s i n l e r i n g b e l o w 1 3 5 0 . c i s a d v i s e d t o p r e v e n t production of reaction phases. however, high temperature is rcquired to inrprove tbe sintered density b y t h e r m a l a c t i v a t i o n . 2.the physical and dielectric properties influence by ihe bttiratio, sintering temperature and the soaking time. i.increasing tio: in a small proportion effect iargely the p l y s i c a l a n d d i e l e c r r i c d r o p e r t i e s o f r h e r c s u h e d p i e c e . .l.lncreasing bacoj in a quantity larger rhan that oftio, also effect dr€ physical and dielectric propedies of batio3. but the small addition of tio? effect is more e f f e c t i v e r h a n t h a r o f l a r g e r a m o n t o f b a c o r . different perc€ntage l/cm') and i j c p e v o l . b n o . 1 ( m a f c h 2 0 0 7 ) ijcpe vol.10 no.3 (september 2009) iraqi journal of chemical and petroleum engineering vol.10 no.3 (september 2009) 31-39 issn: 1997-4884 effect of additives on rheological properties of invert emulsions muhanned a.r mohammed and samar ali abed mohammed chemical engineering department college of engineering university of nahrain – iraq abstract this research deals with study of the effect of additives on rheological properties (yield point, plastic viscosity ,and apparent viscosity) of emulsions. twenty seven emulsion samples were prepared; all emulsions in this investigation are invert emulsions when water droplets are dispersed in diesel oil. the resulting emulsions are called water -in-oil (w/o) emulsions. the rheological properties of these emulsions were investigated using a couett coaxial cylinder rotational viscometer (fann-vg model 35 a), by measuring shear stress versus shear rate. it was found that the effect of additives on rheological properties of emulsions as follow: the increase in the concentration of asphaltic material tends to increase the rheological properties of emulsions, the increase in the volume percentage of barite tends to increase the rheological properties of emulsions and the increase in the volume percentage of emulsifier has a little effect on the value of rheological properties, but in the same time it increase the stability of emulsions with temperature because it surrounded water droplets. keywords: rheology, emulsions introduction rheology is the study of the deformation and flow of matter under the influence of an applied stress, for example a shear stress or extensional stress. rheology of emulsion has two aspects in order to determine the rheological properties of emulsions. the first concerned with their effects on emulsion stability while the other involves the effects of deterioration of the emulsion on its rheological properties. the principle factors, which influence the flow properties of emulsions, are related to the dispersed phase, continuous phase and the emulsifying agent. a change in one or more of these factors will affect the rheological properties of an emulsion. factors which related to the dispersed phase are concentration (i.e. phase volume ratio), viscosity and the size of the dispersed droplet [3, 4]. a direct relation ship between the viscosity of emulsion and the viscosity of the dispersion medium always exists. sherman (1964) describes the viscosity of the dispersion medium as not only the viscosity of the pure dispersion fluid but it's viscosity when all the ingredients in the formula have been dissolved in it , e.g. emulsifying agent [5]. different emulsifying agents give rise to different flow properties. the chemical nature of emulsifying agent is also important which may lead to the flocculation of the dispersed droplet, that will tend to produce plastic flow [3,6]. an additional factor, which may affect the viscosity of the emulsions which is the electro viscous effect. highly charged dispersed droplet require an additional shear in order to destroy the configuration of the electrical double layer around each droplet so such emulsions exhibit a higher viscosity [3]. an emulsion is a system containing two liquid phases, one of which is dispersed as droplets in the other. the liquid which is broken up into droplets is termed the dispersed phase, whilst the liquid surrounding the droplets is known as the continuous phase or dispersing medium. the two liquids, which must be immiscible or nearly so, are frequently referred to as the internal and external phases, respectively. university of baghdad college of engineering iraqi journal of chemical and petroleum engineering http://en.wikipedia.org/wiki/matter http://en.wikipedia.org/wiki/stress_(physics) http://en.wikipedia.org/wiki/shear_stress http://en.wikipedia.org/wiki/extensional_stress effect of additives on rheological properties of invert emulsions 32 ijcpe vol.10 no.3 (september 2009) there are many types of emulsions, depending on which one is the dispersed (internal) phase or dispersing (external) phase. it is common practice to describe an emulsion as being either oil-in-water (o/w) or water-inoil (w/o). where the first phase mentioned represents the dispersed phase and the second is the continuous phase. the third type of emulsions is called multiple emulsions. a multiple is one, which grater of two types of emulsions simultaneously. an oil droplet may be suspended in an aqueous phase, which is turn encloses a water droplet. thus giving what might be describe as w/o/w multiple emulsion or o/w/o multiple emulsion, which have the reverse composition. this type of fluid will behave as a solid under static conditions. a certain amount of force must be applied to the fluid before any flow is induced; this force is called the "yield value". once the yield value is exceeded and flow begins, plastic fluids may display newtonian, pseudo plastic, or dilatants flow characteristics [8]. experimental work all emulsions prepared in this investigation are invert emulsions when water droplets are dispersed in oil. the resulting emulsions are called waterin oil emulsions (w/o). generally, w/o-emulsions are preferred when a large amount of oil is desired. diesel oil was used as the external phase of all samples being tested, and distilled water was used as the dispersed phase with powdered sodium chloride to provide the salinity of the water phase. additives which were used as follow a soluble oil additive as emulsifying agent, barite as weighting material, lime to provide alkalinity, organophilic clay to suspend the weight material, and finally asphaltic material to provide emulsion stability at high temperature, and gel strength. experimental procedure it was found that the following mixing procedure included sequence of additives and mixing periods gave best results in preparing emulsions as shown below: 1. 475 ml diesel oil was measured in a beaker and placed in the hamilton beach cup. 2. 25 ml of water was measured in beaker. 3. nacl salt was added to beaker of water 4. emulsifier (soluble oil additive) was added at desired concentration , concentrate drop by drop to the diesel oil in the hamilton beach cup while mixing, and mix for 60 minutes. 5. all powder materials and additives were weighted by using electronic balance, some of these materials are changed in tests and the others are constant as shown in table 1. 6 lime additive was added slowly and mix for 30 minute. 7. required volume of brine was added slowly while mixing and mix for 45 minutes. table 1 constant material for all tests. weight (gm) material 23.7 lime (cao) 2.37 organophilic clay 7 nacl (salt) 8. asphaltic material additive was added and mix for 30 minutes. 9. organophilic clay additives were added and mix for 30 minutes. 10. the total amount of barite was added as slow as possible to obtain the required final percentage volume of barite. then mix the final mixture for 30 minutes. 11. the prepared solution was kept at rest at room temperature for 24 hour prior to conducting the rheological measurements. fann viscometer model 35 a testing procedure twenty seven emulsion samples were tested using the fann viscometer model-35 a. these samples included three various volume percentage of barite, with three different volume percentage of emulsifier and three different concentrations of asphaltic material. the emulsion samples were tested for rheological properties under three different temperatures of 77 ° f, 122 ° f and 167 ° f, at each temperature the rheological properties were measured. before any test, the viscometer was calibrated for both shear rate and shear stress to be insuring that it will give accurate results. the sample cup was filled with emulsion sample prepared at 25°c (77°f) to the scribed line, and the rotor was immersed to the proper immersion depth. the instrument was operated at 300 rpm for three minutes to equalize the temperature of the bob, rotor and emulsion. the instrument switched to 600, 300, 200, 100, 6, and 3 rpm and the dial reading was recorded. the procedure was repeated the above procedure to the emulsion sample after heated to 50°c (122 ° f), and then after heated to 75°c (167 ° f). then: 300600  p (1) 300  ppy (2) muhanned a.r mohammed and samar ali abed mohammed ijcpe vol.10 no.3 (september 2009) 33 2 600 a (3) where θ600 = dial reading at 600 rpm θ300 = dial reading at 300 rpm results and discussion effect of asphaltic material on rheological properties of emulsions the effect of asphaltic material on rheological properties (yield point, plastic viscosity ,and apparent viscosity) of emulsions under different temperatures are clearly shown in figures 1 to 3 respectively. since, the values of yield point, plastic viscosity, and apparent viscosity are plotted versus the weight of asphaltic material respectively. the emulsions prepared were in satisfactory conditions at temperatures up to 75 c (167 f) with 35.5 gm asphaltic material, it was decided to increase the concentration of asphaltic material to 40.5 and 45.5gm, with three different volumes percentages of barite (0.46%, 0.65% and 0.84%) to demonstrate its effect on rheological properties of emulsion with temperature. from these figures, one can notice that the increase in weight of asphaltic material tends to increase the yield point, plastic viscosity and apparent viscosity, the increase in the weight of asphaltic material will result in a smaller size water droplet, fully emulsified. this lead to reduce the surface tension, and provide large surface area. the emulsified water droplets act as solid in the emulsion as stated before, therefore it will result in further increasing in friction and attraction forces between the solid particles in emulsion samples. this will cause increasing the plastic viscosity, yield point and apparent viscosity of the emulsions. the increase in the attraction forces is more obvious even at high temperatures which increase the yield point to a certain limit. effect of barite on rheological properties of emulsions the effects of barite on rheological properties (yield point, plastic viscosity and apparent viscosity) of emulsions under different temperatures are clearly shown in figures 4 to 6. since, the values of yield point, plastic viscosity, and apparent viscosity are plotted versus the volume percentage (vol. %) of barite, respectively. from these figures, one can notice that the increase in the volume percentage of barite tends to increase the yield point, plastic viscosity and apparent viscosity due to the increasing in solid content. the addition of solid material will increase friction and attraction forces between the solid particles, so according to that, will result in an increase in yield point, plastic viscosity and apparent viscosity. effect of emulsifier on rheological properties of emulsions the effects of emulsifier on rheological properties (yield point, plastic viscosity and apparent viscosity) of emulsions under different temperatures are clearly shown in figures 7 to (9). since, the values of yield point, plastic viscosity, and apparent viscosity are plotted versus the volume percentage (vol. %) of emulsifier (lubrizol becrosan), respectively. from these figures, firstly one can notice that at room temperature 25 °c (77 °f), the increase in the volume percentage of emulsifier tends to increase the yield point, plastic viscosity and apparent viscosity because the emulsifier is effective by forming a mechanical barrier that surrounded water droplets and the emulsifier sufficient to coat all the water droplets, also it increases the viscosity of the oil continuous phase. insufficient emulsifier concentration will result in a break down of emulsion with increasing temperature that will lead to a free water phase in the emulsion, which causes water-wetting of solid constituents in the emulsions, especially barite. water-wetting of barite causes it to be settled, that will increase the rheological properties. it was noticed that the increase in volume percentage of emulsifier has no appreciable effect on the values of plastic viscosity, yield point and apparent viscosity but it resulted in a stronger with better tolerance to temperature. this effect may be more pronounced for a large quantity of emulsifiers. effect of additives on rheological properties of invert emulsions 34 ijcpe vol.10 no.3 (september 2009) fig. 1 effect of concentration of asphaltic material on yield point of emulsions with barite= 0.46 vol. % fig. 2 effect of concentration of asphaltic material on plastic viscosity of emulsions with barite = 0.46 vol. % muhanned a.r mohammed and samar ali abed mohammed ijcpe vol.10 no.3 (september 2009) 35 fig. 3 effect of concentration of aspaltic material on apparent viscosity of emulsions with barite = 0.46 vol. % fig. 4 effect of vol. % of barite on yield point of emulsions with emulsifier = 3.2 vol. % effect of additives on rheological properties of invert emulsions 36 ijcpe vol.10 no.3 (september 2009) fig. 5 effect of vol. % of barite on plastic viscosity of emulsions with emulsifier = 3.2 vol. % fig. 6 effect of vol. % of barite on apparent viscosity of emulsions with emulsifier = 3.2 vol. % muhanned a.r mohammed and samar ali abed mohammed ijcpe vol.10 no.3 (september 2009) 37 fig. 7 effect of vol. % of emulsifier on yield point of emulsions with barite = 0.84 vol. % fig. 8 effect of vol. % of emulsifier on plastic viscosity of emulsions with barite = 0.84 vol. % effect of additives on rheological properties of invert emulsions 38 ijcpe vol.10 no.3 (september 2009) fig. 9 effect of vol. % of emulsifier on apparent viscosity of emulsions with barite = 0.84 vol. % conclusions from the present study, one can conclude the followings: 1) the increase in the concentration of asphaltic material tends to increase the yield point, plastic viscosity and apparent viscosity of emulsions. 2) the increase in the volume percentage of barite tends to increase the yield point, plastic viscosity, and apparent viscosity of emulsions. 3) the emulsifier should be added in a sufficient quantity to get a stable emulsion with temperature since it surrounded water droplets. it has a little effect on the rheological properties of emulsions at 122,167 °f, but its effect is clearly shown at room temperature (25°c) 77°f. nomenclature symbol meaning unit p bingham plastic viscosity cp py yield point lb/100 ft 2 a apparent viscosity cp  dial reading deg references 1. chhabra r.p., and richardson r., " non-newtonian flow in process industries " , elsevier pulishing ltd. (1999). 2. criddle d.w., " rheology theory and applications ", (f. eirich, ed.), vol. 3. pp. 429-442, academic press, new york and london (1960). 3. sherman p., " rheological properties of emulsion ", new york, (1983). 4. becher p., " emulsion theory and practice", 2nd ed ., reinhold publisher grop, new york, (1965). 5. clayton w., " theory of emulsions and their technical treament", 4th ed., the blakiston co., new york, p.1 (1943). 6. becher p., " principles of emulsion technology ", p. 2, new york, reinhold publishing crop., (1955). 7. achimescu d., " rheology of quick sand and polyethylene oxide ", department of chemical engineering, university of amsterdam, 2004. 8. tanner r.i., and walters, k., " rheology: an historical perspective ", elsevier, amsterdam (1998). muhanned a.r mohammed and samar ali abed mohammed ijcpe vol.10 no.3 (september 2009) 39 9. wikipedia free in cyclopedia 2007. http://en.wikipedia.org/wiki/barite 10. fann viscometer, model 35 a manual http:// www.expotechusa.com/manuals/fann/35496 .pdf 11. sherman, p. , " emulsion science ", ed., acadimec press inc., londan (1968). 12. gillespie, t., " rheology of emulsion", (p.sherman, ed), pp. 115-124, pergamon press, london, (1963). 13. kirk-othemer, " encyclopedia of chemical technology ", 4th edition, vol. 21, john wiley and sons (1998). 14. mohammad a.r. , and mahammed s.a.a. , " effect of additives and temperature on the rheological behavior of invert (w/o) emulsions ", m.sc. thesis, al-nahrain university, (2009). تأثير اإلضافات على الخىاص الريىلىجية المستحلبات العكسية مهند عبد الرزاق محمد و سمر علي عبد محمد انؼشاق-تغذاد/جامؼح انىهشيه/كهيح انهىذسح / قسم انهىذسح انكيمياويح الخالصة (انهضوجح انهذائىيح وانهضوجح انظاهشيح , وقطح انخضىع )يهرم هزا انثحث تذساسح ذأثيش االضافاخ ػهى انخىاص انشيىنىجيح .نهمسرحهثاخ حيث كم انمسرحهثاخ انمحضشج هي مسرحهثاخ ػكسيح ػىذها ذكىن قطشاخ انماء مىرششج خالل , ومىرج مسرحهة 27ذم ذحضيش . وفط – في –صيد انذيضل وانىريجح ذسمى مسرحهثاخ ماء صيادج ذشكيض انمادج االسفهريح يضيذ مه انخىاص :وجذ إن ذأثيش اإلضافاخ ػهى انخىاص انشيىنىجيح نهمسرحهثاخ هي كاألذي صيادج انىسثح انحجميح نهثاسايد يضيذ مه انخىاص انشيىنىجيح نهمسرحهثاخ ايضا وصيادج انىسثح انحجميح , انشيىنىجيح نهمسرحهثاخ نؼامم االسرحالب نه ذأثيش قهيم ػهى قيم انخىاص انشيىنىجيح ونكىه يضيذ مه اسرقشاسيح انمسرحهثاخ مغ دسجح انحشاسج ورنك ألوه .يحيط تقطشاخ انماء http://en.wikipedia.org/wiki/barite http://www.expotechusa.com/manuals/fann/35496.pdf http://www.expotechusa.com/manuals/fann/35496.pdf dr abbas _mag_.doc ijcpe vol.8 no.4 (december 2007) 39 iraqi journal of chemical and petroleum engineering vol.8 no.4 (december 2007) 39-44 issn: 1997 -4884 prevention of scale formation in heat exchanger pipes by using magnetic field abbas h. sulaymon*, and jassim m. al-kyayyat** *environmental engineering department college of engineering university of baghdad – iraq **chemical engineering department college of engineering university of baghdad – iraq abstract the possibility of using the magnetic field technique in prevention of forming scales in heat exchangers pipes using hard water in heat transfer processes, also the studying the effective and controllable parameters on the mechanism of scale formation. the new designed heat exchanger experimental system was used after carrying out the basic process designs of the system. this system was used to study the effect of the temperature (40-90 °c) and water flow rate (0.6 -1.2 l/min) on the total hardness with time as a function of precipitation of hardness salts from water and scale formation. different magnetic field designs in the heat exchanger experimental system were used to study the effect of magnetic field design and strength (200-500 gauss) on the total hardness with time as a function of precipitation of hardness salts from water and scale formation. keywords: scale formation, heat exchanger. introduction in many of the application of heat transfer plants, one or more of the mechanisms of heat transfer (conduction, convection or radiation) may be involved. in the majority of heat exchangers heat passes through a series of different intervening layers before it reach the second fluid. these layers may be of different thickness and different thermal conductivity. after prolonged usage, solid deposits may form on both the inner and outer walls of the pipes, and these will then contribute as an additional resistance to the transfer of heat. [1] generally, water used in commercial application is not pure water but contains a variety of anions, cations, dissolved gases, and particulate matter. when this aqueous raw material is concentrated, blended, pressurized, seeded or ph adjusted, combination as scale forming anions and cations can exceed their solubility limit and deposits can occur. these water-formed deposits may be reduced or eliminated by the removal of undesirable anions and cations by precipitation or ion exchange reactions soluble or suspended or complex formation. often the deposition can be controlled by ph adjustment or additives. [2] experimental work purpose of investigation private companies or some research scientific stations mainly carry out previous investigations on prevention of forming scales process by magnetic field. detailed information is kept proprietary as (know how). additional work on the mechanism of scale -ban is needed since published data on this subject are rather limited. university of baghdad college of engineering iraqi journal of chemical and petroleum engineering prevention of scale formation in heat exchanger pipes by using magnetic field ijcpe vol.8 no.4 (december 2007) 40 the purpose of this work is to study the prevention of forming scales on pipes of heat exchangers in a new experimental heat exchanger system and to search for the best design of magnetic field and conditions that can be used. the effect of temperature, time (flow rate of hard water), total hardness, magnetic field strength, surface tension, viscosity, and ph was studied. basic process design of system the components of the systems are shown in the figure (1), the system consists of: (a)galvanized hard water tank which have 130l volume. (b)magnetic field is used for treatment section of carbonsteel pipe, which have 1inch (2.54cm) diameter and 70 cm length. (c)experimental heat exchanger made of stainless -steel 316l, which used in it an electric heater (3000w) type to heat the hard water, which have 4l volume. (d)a.c. power supply, as variac type (50 bm), which have (0-270) v, (0-25) a, and 7.5kva from (the zenith electric co. ltd). (e)qvf glass condenser used to cool the hard water which has 0.5m length and 2 inch (5 cm) diameter within two sides of coils. (f)pvc hard water tank, which have 30l volume. (g)centrifugal pump (stuart turner ltd) which has 313.7m head, 11.4 -54.5l/min and (150-720) gph. figure (1) experimental heat exchanger system magnetic field design this design is using vertical turn of the coil around the pipe of 30cm length at each of the two parts of the total path show in figure (2) type of coil (swg30), the magnetic field requirement can be achieved by changing the electrical power from a.c. power supply using the (variances) and. the types of the two variacs is hsn0103 220v plug, 5a and 1.25kva.an alternative approach is to use electrical current flowing through coils of wire warped around the water pipe to generate the magnetic field . figure (2) first design of magnetic field in the system measurements temperature of water temperature of the water was measured by means of mercury in glass thermometer in range ( -4 – 250 oc). volumetric flow rate of water volumetric flow rate was measured manually, using the volumetric flask and stop-watch to measurement the volumetric flow rate of hard water and cooling water in the system or by flow indicators. a.c./d.c. current electric current and voltage measured by means of digital clambmeted type. ph of water all ph values were determined by using metrohm agch-9100 herisau ph meter, and calibrated by standard buffer solution (ph=4,7) depending on the worked zone. total hardness of water the total hardness of water was measured by edta titration method; the standard method was used as follows; (a)preparing a standard calcium solution by dissolving accurately weighted 0.5g portion of pure caco3 in (40ml) 1m hcl and diluting to (500ml) in a volumetric flask used to calibrated the (na2 edta) solution, from time to another time. (b)preparing the ammonia buffer solution by dissolving (16.9 g) of nh4cl in (143 ml) of concentrated nh4oh, that first solution, and the following second abbas h. sulaymon and jassim m. al-khayyat ijcpe vol.8 no.4 (december 2007) 41 solution prepared from dissolving (1.179 g) na2edta and (0.644 g) mgcl2.6h2o in (50 ml) of distillated water, and by adding first solution to second solution, and diluting to (250 ml) with mixing and placing in a closed volumetric flask. (c)preparing eriochrome black-t indicator by mixing (0.8 g) of eriochrome black-t with (100 g) of nacl using milling for solid materials. (d)preparing the (0.01m) na2edta by dissolving (3.723 g) dehydrate in distillate water and complete the volume to (1l) in volumetric flask. the procedure of measuring the hardness of water consists of (10 ml) of hard (tap) water and diluting to (50 ml) by distillated water in a conical flask with adding (1 ml) of ammonia buffer solution to obtain the (ph=10) solution. after that added (0.1 g) of indicator to obtain the red (purple) color, and then titrate with the (0.01 m) na2edta solution. the end point was color changes from win red (purple) calculate the total hardness as caco3 is done by using equation (3.1). mg/l hardness as caco3 = mlsample axbx 1000 (1) after calibrated (na2 edta) solution with standard calcium solution, then (1 mg) of caco3 equivalent to (100 ml) of na2edta solution. if the concentration of na2edta is (0.01m) then (b=1), and a is milliliters of na2edta solution for titration. magnetic field strength magnetic flux density or magnetic field strength was measured by using the hirst gmo4 handhels gaussmeter, surface tension of water . surface tension of water was measured by means of the surface tension meter type (kruss gmbh hamburg 90324, germany). to determine the value of surface tension equation (3.2) was used. f×ρ=σ (2) where p is the tensiometer reading, and f is the correctio n factor, practical was equal to (1.39). viscosity of water. viscosity of water was measured by means of the viscometer glass tube, type (volac b5.ip.cf71) size 50. to determine the value of kinematics viscosity equation (3.3) was used. the unit of kinematics viscosity in the relation is (c. stock or mm2/s). η =time×0.004 (3) x-ray diffraction. the x-ray diffraction used to determine the type of scale crystals and estimated relative line intensities. this test was carried out in (s.c. of geological survey and mining). water analysis the analysis of the tap (hard) water which used in the experimental was carried out in (s.c. of geological survey and mining) to determined the water content. scale crystals photography. the scale crystals photographed was carried out by using the photomicrograph in (al-nahrain university) to obtain the type and shape of scale crystals. by using the light microscope with digital camera type (olympus, ch40). results and discussion scale formation stage before the treatment by magnetic field, the formation of scales conditions and the behavior of hardness salts in the water were studied. from the water analysis results, the water contents (cation ions, anion ions, impurities, t.d.s.….etc) can be determined the type of scales. the formations of scales depend on the temperature and volumetric flow rate of hard water (tap water) in the system. the scale formation is also a function of the precipitation of hardness salts in the water as found in the total hardness of hard water testing. the viscosity, surface tension, and ph of hard water also depend on the temperature and water contents. the influences of these properties were tested. after the system reached to steady-state (closed system), these testes were carried out as a series of (6 hours) cycles for one day. after the formation of scales, the shape and type of scales were determined by using x-ray diffraction and photomicrograph at the same temperature. the best process conditions when studying th e influence of temperature and flow rate of hard water in the system on the total hardness and physical properties of hard water, the best process conditions can be determined by the following factors: a-the explanatory effect on the total hardness of water. b-the controllability on the condition system. c-the suitable design of magnetic field. the best process conditions (temperature) were processes at (70) o c, figure (3)due to the best process and best volumetric flow rate of hard water in the system. after long time (50-60 day) the scale were form on the hot surface of the system, samples were taken and analysis using x-ray diffraction test and photomicrograph prevention of scale formation in heat exchanger pipes by using magnetic field ijcpe vol.8 no.4 (december 2007) 42 to determine the type of scales, intensity, structure of scale crystals, and shape of crystals, figures (4 and 5). figure (4) x-ray diffraction for scale samples at heater surface of heat exchanger without magnetic field figure (5) photomicrograph of scales from heater surface without magnetic field effect of magnetic field strength the magnetic field strength was found to affect the precipitation of hardness salts, crystallization stages crystal structure and corrosion of metals. effect on the precipitation the magnetic field strength influences the precipitation of hardness salts in water. the magnetic field strength effectiveness due to the decreasing the precipitation of hardness salts. it can be seen that an increasing in the total hardness of water as in figure (6). the magnetic field strength which was (400-500) gauss. this phenomenal appears at the same case for the effect of flow rate of hard water, when decreasing the volumetric flow rate of hard water leads to increasing the effect of the magnetic field system. shows plotting the (t.h) with temperature. the precipitation of hardness salts using magnetic field will lead the magnetic field to affect the physical properties of water such as decreasing the surface tension and increasing the viscosity of water . effect on the crystallization the magnetic field strength influences the crystallization stage. when increasing the strength and contact area of magnetic field will effect on the crystallization stage and cause it to be more unstable and decreasing the intensity of crystals as (aragonite) shown in x-ray diffraction figure (7). it was found that at high magnetic field strength and large contact areas between the magnetic field and the hard water will cause bounded the crystallization stage at least level and prevention it. effect of the crystal structure using the magnetic field will affect the crystallization behavior and converted it from calcite to aragonite, which has a minor stability and un charges crystal germs. at greater quantity of germs the more fine amorphous crystal mud wa s formed as shown in photomicrograph figure (8). figure (3) total hardness (t .h.) vs. time at 70 c 0 50 100 150 200 250 300 350 400 0 10 20 30 40 50 60 time (hr.) t .h . ( p p m ) 1.2 (l/min) 0.86 (l/min) 0.6 (l/min) figure (6) total hardness (t.h.) vs. time at 70 c 0 50 100 150 200 250 300 350 400 0 10 20 30 40 50 60 time (hr.) t .h .( p p m ) 1.2 (l/min) ,(400-500 gauss) 0.86 (l/min) ,(400-500 gauss) 0.6(l/min),(400-500 gauss) 0.6(l/min),(200-300 gauss) abbas h. sulaymon and jassim m. al-khayyat ijcpe vol.8 no.4 (december 2007) 43 figure (7) x-ray diffraction for scale from the heater surface with magnetic field figure (8) crystal mud photomicrograph effect on the corrosion the magnetic field used on the system was influenced the rate of corrosion and decreased it to a minimum rate (prevented it). conclusions 1-the new heat exchanger experiments system design was very suitable system to study the scale formation. 2scale formation at inverse solubility region is not dependent on the water content and temperature but influenced by water flow rate and time. 3-the amount of scale formation increased with increasing the hardness of water and time of heating. 4-the effects of magnetic field strength and design on the scale formation at all stages showed that a suitable strong magnetic field cans prevent the formation of scales. 5-the prevention of forming scales depends on the water flow rate and magnetic field strength and design. 6-the strong permanent magnetic field was found to be magnetic field design in order to prevent the scale formation. 7-using a suitable strong magnetic field will reduce the rate of corrosion of the metal and prevent it. 8-the magnetic field strength depends on the water flow rate in the system. references 1. coulson, j.m., richardson, jf, backhurst, jr., and harker, jh. 1977. chemical engineering. vol .1. 3rd. edition. pergaman press. 2. ghanim, ala. nou. 1986. removal of scale deposited on surface of heat transfer equipment by chemical methods. un iversity of baghdad. jan. 3. geary, david, tc 3.6. 1995. winter meeting. ashrae journal. april: 18 & 36. 4. diamante, r.m.e. 1972. applied chemistry for engineers. 3rd. edition. pitman publishing. 5. hadi, moh. has. 1991. removal of scale deposited inside carbon steel heat exchanger tubes using inhibited with hexamine. university of baghdad sept. 6. schnell, dipl. eng. h. 1998. physical water treatment, nielsen technical trading. germany. www.aqua. correct. com ./ denmark 7. coulson, j.m. richardson, jf sinnott, rk. 1985 . chemical engineering. vol. 6. 1st edition. pregamon press. 8. holman, j.p. 1981. heat transfer. 5th edition. mcgraw-hill. 9. forums, eng-tips, 2004. heat transfer & thermodynamic engineering. technical work forums for engineering professionally. aug 2. (www.engtips. coml.). 10. perry, r.h., and chiloin, c.h. eds. 1973. chemical engineers handbook. 5th ed. mcgraw-hill. 11. frank, o. 1974. estimation overall heat transfer coefficient. chem.eng. albany 81. may 13th :126 12. tema.1978.standards of the tubular heat exchanger manufactures association. 6th ed. tubular hat exchanger manufactures association. new york. 13. ludwig, e.e. 1965. applied process design for chemical and petroleum plants. vol. 3. gulf. 14. george am. ra. 1994. scale effect on condensers performance under various operating conditions. university of baghdad. july. 15. knudsen, j.g. 1984. fouling in heat exchangers. hemisphere publishing corporation. 16. advanced heat transfer. 1999. an overview of heat exchanger fouling-costs and fundamentals. www. fbhx-usa.com /. february 15. prevention of scale formation in heat exchanger pipes by using magnetic field ijcpe vol.8 no.4 (december 2007) 44 17. shreve, r. nor., and brink, jos. a., jr. 1977. chemical process industries. 4th edition. mcgrawhill kogakusha. 18. natural water. 2004. on view at museum of science boston, massachusetts oct .10, 1998 tp jan. 3, 1999. (www. science. uwater 100. ca / 19. derwent water systems limited. 2004. manufacturers & suppliers of water treatment. spares & equipment. www. derwent water systems. co. uk /. 20. delpierre, g.r., and sewell, b.t. 2002. physchem. solutions. www. physchem. co. uk /. ijcpe vol.9 no.3 (septemper 2008) iraqi journal of chemical and petroleum engineering vol.9 no.3 (september 2007) 17-24 issn: 1997-4884 dye removal from wastewater using iron salts dr. adil al-hemiri * , hameed al-anbari ** and ibtihal k. shakir *** *, *** chemical engineering department, college of engineering, university of baghdad ** ministry of industry abstract this investigation was carried out to study the treatment and recycling of wastewater in the cotton textile industry for an effluent containing three dyes: direct blue, sulphur black and vat yellow. the reuse of such effluent can only be made possible by appropriate treatment method such as chemical coagulation. ferrous and ferric sulphate with and without calcium hydroxide were employed in this study as the chemical coagulants. the results showed that the percentage removal of direct blue ranged between 91.4 and 94 , for sulphur black ranged between 98.7 and 99.5 while for vat yellow it was between 97 and 99. key words: dye removal by iron salts, dye removal from wastewater. introduction the urgent need to conserve, recycle and reuse the limited water sources of the earth has forced mankind to research and develop new methods and technologies for treating and managing used waters from process, cooling and/or rinse facilities of industrial applications. this is especially important in textile finishing and dyeing industries, where huge amounts of water are consumed in dyeing and washing/rinsing of the fabrics [1]. textile mill operations consist of weaving, dying, printing, and finishing. many processes involve several steps, each contributing a particular type of waste, e.g. sizing of the fibers, queering (alkaline cooking at elevated temperature), desizing the woven cloth, bleaching, mercerizing, dyeing, and printing. textile wastes are generally, colored, highly alkaline, high in bod and suspended solids, and high in temperature. wastes from synthetic-fiber manufacture resemble chemical-manufacturing wastes and their treatment depends on the chemical process employed in the fiber manufacture. equalization and holding are generally preliminary steps to the treatment of those wastes because of their variable composition. additional methods are chemical precipitation, trickling filtration, and, more recently, biological treatment and aeration. the textile industry has long been one of the largest of water users and polluters and there has been little success in developing low-cost treatment methods, which the industry urgently needs to lessen the pollution loads it discharges to streams [2]. coagulation is the method in which certain chemicals are rapidly dispersed in wastewater to change the characteristics of the suspended particles so that they coalesce and form flocs that sink rapidly. coagulation is employed to improve or make possible the removal of negatively charged colloidal suspensions, which do not normally settle out and cannot be removed by conventional physical treatment. coagulation is done by the addition of positive ions, e.g., al3+, which reduce the electrokinetic repulsion between the particles [3]. in industrial wastewater treatment, coagulation is frequently used for oily emulsions, and finely divided and nonsettleable solids such as pigments, paper fiber, meat and tannery effluents, and mineral benefaction slimes. the most widely used coagulants for wastewater university of baghdad college of engineering iraqi journal of chemical and petroleum engineering removal of asasbn sdfs fs f sf sdfsdfsdf fsdfsdfsdfs fsdfsdfsd 2 ijcpe vol.9 no.3 (septemper 2008) treatment are aluminum and iron salts such as aluminum sulphate (alum), ferric sulphate, and ferric chloride. at high (alkaline) ph prevalent in the water these salts produce insoluble aluminum hydroxide or ferric hydroxide flocs [4]. the overall reaction may be represented as:   24323342 63)(2)(3 cocasoohalhcocasoal  as they form and grow, the aluminum hydroxide flocs entrap the solid particles. the precipitate is then flocculated to produce large, dense settleable solids. sometimes, with very low concentration of colloidal matter, floc formation is difficult; therefore, coagulant aids like polyelectrolytes are added to promote the coagulation-flocculation process [5]. if properly performed, the addition of chemicals for promoting coagulation and flocculation can remove both suspended and colloidal solids. after the flocs are formed, the solution is led to settling tank where the flocs are allowed to settle, while most of the flocculated material is removed in the settling basin. these flocs are removed by the process [6]. ince and tezcanli (1999) investigated the treatability of textile dye-bath effluents by advanced oxidation with fenton and fenton-like reagents (fe ii / h2o2 and fe iii / h2o2), in the presence and absence of uv light, using a reactive azo-dye (procion red he7b), and typical dye bath constiuents. under the experimental conditions employed, it was found that with 20 minutes uv irradiation, complete colour removal and 79% total organic carbon degradation is possible, when the system is operated at ph = 3, and with a h2o2 / fe ii molar ratio of 20:1. the individual effects of h2o2 and fe ii injections to the uv-irradiated dye solution were tested by running the advanced oxidation respectively with fe ii, h2o2 and both (at molar h2o2/ fe ii ratios of 20:1). the data is plotted in fig. (2.10). total colour removal with uv / fe ii, uv / h2o2 and uv / fe ii: h2o2 were found to be 30%, 90% and 97% respectively. furthermore, the rate of colour degradation was unaffected by the variations in the ratio (h2o2 / fe ii) under dark conditions, whereas the degradation was found to be 0.75 times faster at a ratio of 20:1 than at 10:1, when the solution was irradiate a survey was made to study the industrial wastewater problem in ten different factories in and around baghdad. the survey included the amount of feed water to the factory, the amount of industrial wastewater leaving the factory, the amount of treated water, and major physical and chemical properties of industrial wastewater before and after the treatment unit. it was concluded from this survey that the textilefinishing industry uses large quantities of water (150 m3/hr) and produces large volumes of aqueous effluent ( 125 m3/hr). the provision of water and disposal of effluents cannot be viewed as two separate problems as the viability of the industry in the future may well depend on the extent to which water can be reused. experimental work chemicals used: ferrous sulphate, ferric sulphate, ferric chloride and calcium hydroxide all of technical grade. procedure and equipment: preliminary experiments were carried out to find the effect of the rate of agitation and the agitation time. these were fixed at their best value of 350 rpm and 30 minutes respectively. analysis of the waste water from the cotton textile treatment showed that the maximum concentrations of each dye were 6,10 and 16 ppm for direct blue, sulfure black and vat yellow respectively. thus a model dye solutions were prepared by dissolving a weighed amount of the powder dye in distilled water. each dye solution was mixed with the above mentioned coagulants in a one-liter vessel at a constant speed (350 rpm) and a temperature of 27c for about 30 minutes. it was then filtered using slow medium filter paper. the filtered solution was analyzed using uvspectophotometer to find the dye concentration. discusion addition of ferrous sulphate feso4 figure (1) indicates that increasing the amount of ferrous sulphate added will increase the removal of dye. a complete decolorization has been achieved for sulphur black dye solution at 0.2 gm/l ferrous sulphate dose, while the direct blue dye solution had a moderate decolorization (91%). further observations showed that the vat yellow dye solution can not meet the required percent dye removal for the purpose of industrial wastewater recycling. figure (2) shows the effect of ferrous sulphate dose to mixture of dyes in water. the behaviour of vat yellow dye controls the overall behavior of mixture dyes solution especially the sulphur black dye. this behaviour is probably due to the interaction between the molecules of dye-ferrous sulphate products in the mixture solution, which decreases the ability of formation of the coagulant. for this reason the use of ferrous sulphate as a coagulant is not recommended unless using another material with it, for example calcium hydroxide ijcpe vol.9 no.3 (septemper 2008) addition of ferrous sulphate and calcium hydroxide figures (3) to (6) show the effect of adding calcium hydroxide as well as ferrous sulphate for dye removal. calcium hydroxide improved the decolorization even with small doses. this is probably due to the neutralization of the colloidal charge by flooding the medium with an excess of oppositely charged ions. usually hydrous oxide colloids are formed by reaction of the coagulant with ions in the water. the coagulant colloid also becomes destabilized by the reaction with foreign, oppositely charged colloids and produce hydrous oxide, which is a floc-forming material. the same behaviour can be achieved for direct blue dye removal with 0.05 gm calcium hydroxide dose if the dye was in water alone or with the mixture of dyes. for sulphur black and vat yellow, the removal of dye increase slightly. figure (4) clearly demonstrates that increasing the amount of feso4 added had no effect in the dye removal of direct blue and sulphur black dyes, while for vat yellow dye removal increases up to 92% using 0.05 gm ferrous sulphate dose then the same behavior can take place. furthermore figure (6) shows that the concentration of sulphur black and vat yellow dyes dose not change when adding 0.02 gm of ferrous sulphate while the concentration of direct blue dye will reduce with a moderate percent. this may be due to the faster interaction between the direct blue with the coagulant (feso4 + ca(oh)2) compared to other dyes. after that, increasing the amount of ferrous sulphate will cause a step change to reach ultimate removal of all dyes. the best coagulant dose is (0.15 gm/l feso4 and 0.05 gm/l ca(oh)2) to achieve 93%, 99% and 98% for the removal of direct blue, sulphur black and vat yellow respectively. addition of ferric sulphate fe2(so4)3 figure (7) indicates that sulphur black dye reaches nearly a complete dye removal even at 0.02 gm/l of ferric sulphate dose, then any increase of ferric sulphate added had no effect. for the direct blue, dye removal increase gradually with increasing ferric sulphate dose. furthermore, vat yellow dye removal has a sharp increase up to 0.02 gm/l of ferric sulphate added. increasing the ferric sulphte added will cause a gradual decrease in the dye removal. iron oxides can acquire both positive and negative charges. excess fe 3+ makes the colloids positively charged. figure (8) clearly demonstrates that all dyes in the mixture behave like vat yellow dye in water alone as noted in figure (7). this means that vat yellow dye may control the behaviour of the dyes mixture in water. the best ferric sulphate dose to achieve 94%, 99% and 98% dye removal for direct blue, sulphur black and vat yellow respectively is 0.02 gm/l. addition of ferric sulphate and calcium hydroxide sulphur black dye had been completely removed on adding 0.02 gm of ferric sulphate, then addition of any other compound had no significant effect as shown in figures (9) and (10). direct blue dye removal increases by adding 0.1 gm/l of calcium hydroxide to reach 94% removal with 0.02 gm ferric sulphate added. then the addition of more calcium hydroxide (0.5 gm) will reduce the dye removal slightly (91%) as noted in figures (10) and (11) . the addition of calcium hydroxide has a negative effect in vat yellow dye removal. addition of 0.1 gm calcium hydroxide will decrease the removal from 99% to 0.1% , where the 99% removal, being achieved by only 0.02 gm/l ferric sulphate dose. increasing the amount of ferric sulphate up to 0.15 gm will increase the dye removal to 97%. this behaviour is probably due to the difference in structure of each dye and the reaction products of each dye with the coagulant in the aqueous solution. each dye in the solution mixture had nearly the same behaviour of the other dyes, while each dye solution had its own behaviour as noted previously. this is probably due to the interaction between molecules of the dye and its coagulation products with each other. addition of calcium hydroxide even with small amount will prevent the decreasing of dye removal with the increase in the ferric sulphate dose. furthermore, addition of 0.1 gm/l or 0.5 gm/l of calcium hydroxide had no effect on the dye removal of direct blue and sulphur black dyes, figures (8), (12) and (13). the best coagulant dose is (0.15 gm/l fe2(so4)3 + 0.1 gm/l ca(oh)2) to achieve 93%, 99.5% and 97% removal for direct blue, sulphur black and vat yellow respectively. addition of ferric chloride, fecl3 figure (14) shows the effect of adding ferric chloride to direct blue dye in water solution. 70% dye removal can be achieved on adding 0.02 gm/l of ferric chloride. increasing this amount up to 0.2 gm/l will decrease the dye removal to 50%. thus, using this coagulant is not recommended, because it can not meet the dye removal requirements for recycling processes. removal of asasbn sdfs fs f sf sdfsdfsdf fsdfsdfsdfs fsdfsdfsd 4 ijcpe vol.9 no.3 (septemper 2008) weight feso4 added, gm %dye remo val 0 10 20 30 40 50 60 70 80 90 100 0.0 0.2 0.4 0.6 0.8 1.0 direct blue sulphur black vat yellow weight feso4 added, gm % dy e rem oval 0 6 12 18 24 30 36 0.0 0.4 0.8 1.2 1.6 2.0 direct blue sulphur black vat yellow addition of calcium hydroxide alone figure (15) indicats that calcium hydroxide is ineffective for dye removal of sulphur black solution in water. even large amounts of calcium hydroxide added did not improve the dye removal, but rather causing an increase in the turbidity of the solution. while, the addition of calcium hydroxide with ferrous sulphate improves its ability for dye removal, as mentioned before. fig. 1 addition of feso4 to 1 liter of solution of each dye in water fig. 2 addition of feso4 to 1 liter of solution mixture of dyes in water fig. 3 addition of feso4 + (0.05 gm) ca(oh)2 to 1 liter of solution of each dye in water fig. 4 addition of feso4 + (0.1 gm) ca(oh)2 to 1 liter of solution of each dye in water fig. 5 addition of feso4 + (0.05 gm) ca(oh)2 to 1 liter of solution mixture of dyes in water fig. 6 addition of feso4 + (0.1 gm) ca(oh)2 to 1 liter of solution mixture of dyes in water weight feso4 added, gm % dy e rem oval 90 91 92 93 94 95 96 97 98 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 direct blue sulphur black vat yellow weight feso4 added, gm % dy e rem oval 55 65 75 85 95 105 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 direct blue sulphur black vat yellow weight feso4 added, gm % dy e rem oval 91 92 93 94 95 96 97 98 99 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 direct blue sulphur black vat yellow weight feso4 added, gm % dy e rem oval 91 92 93 94 95 96 97 98 99 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 direct blue sulphur black vat yellow ijcpe vol.9 no.3 (septemper 2008) fig. 7 addition of fe2(so4)3 to 1 liter of solution of each dye in water fig. 8 addition of fe2(so4)3 to 1 liter of solution mixture of dyes in water fig. 9 addition of fe2(so4)3 + (0.05 gm) ca(oh)2 to 1 liter of sulphur black dye solution fig. 10 addition of fe2(so4)3 + (0.1 gm) ca(oh)2 to 1 liter of solution of each dye in water fig. 11 addition of fe2(so4)3 + (0.5 gm) ca(oh)2 to 1 liter of solution of each dye in water fig. 12 addition of fe2(so4)3 + (0.1 gm) ca(oh)2 to 1 liter of solution mixture water of dyes in weight fe2(so4)3 added, gm % dy e rem oval 0 20 40 60 80 100 0.00 0.06 0.12 0.18 0.24 direct blue sulphur black vat yellow weight fe2(so4)3 added, gm % dy e rem oval 0 20 40 60 80 100 0.00 0.04 0.08 0.12 0.16 0.20 direct blue sulphur black vat yellow weight fe2(so4)3 added, gm % dy e rem oval 98.0 98.5 99.0 99.5 100.0 100.5 101.0 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 weight fe2(so4)3 added, gm % dy e rem oval 0 20 40 60 80 100 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 direct blue sulphur black vat yellow weight fe2(so4)3 added, gm % dy e rem oval 0 20 40 60 80 100 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 direct blue sulphur black vat yellow weight fe2(so4)3 added, gm % dy e rem oval 74 78 82 86 90 94 98 102 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 direct blue sulphur black vat yellow removal of asasbn sdfs fs f sf sdfsdfsdf fsdfsdfsdfs fsdfsdfsd 6 ijcpe vol.9 no.3 (septemper 2008) fig. 13 addition of fe2(so4)3 + (0.5 gm) ca(oh)2 to 1 liter of solution mixture of dye in water fig. 14 addition of fecl3 to direct blue dye in water fig. 15 addition of ca(oh)3 to sulpher black dye in solution conclusions 1. nearly complete dye removal can be achieved by the addition of ferrous sulphate to individual aqueous solutions of direct blue and sulphur black, while vat yellow is hardly affected. thus ferrous sulphate is not recommended for treatment of a mixture of the three dyes considered. 2. the best coagulant dose for treating a solution of the three dyes considered, here, is 0.15 gm/l feso4 and 0.05 gm/l ca(oh)2 to a colour removal of 93%, 99% and 98% for direct blue, sulphur black and vat yellow respectively . 3. the best dose of ferric sulphate to achieve 94%, 99% and 98% dye removal for direct blue, sulphure black and vat yellow respectively is 0.02 gm/l. 4. ferric chloride is not recommended for the concentration reduction of these dyes. reference 1 atkins, m. h. and lowe, j. f., (1979), “case studies in pollution control measures in the textile dying and finishing industries”, pergamon press, oxford, new york. 2 degremont, (1979), “water treatment handbook”, 5 th ed., halstad press book, john wiley and sons, new york. 3 ince, n. h. and tezcanli, g., (1999), “treatability of textile dye-bath effluents by advanced oxidation: preparation for use”, water science and technology, vol. 40, no. 1, pp. 183-190. weight fe2(so4)3 added, gm % dy e rem oval 72 76 80 84 88 92 96 100 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 direct blue sulphur black vat yellow weight fecl3 added, gm % dy e rem oval 48 52 56 60 64 68 72 76 0.00 0.04 0.08 0.12 0.16 0.20 weight ca(oh)2 added, gm % dy e rem oval 0 2 4 6 8 10 0.00 0.04 0.08 0.12 0.16 0.20 ijcpe vol.9 no.3 (septemper 2008) 4 nemerow, n. l., (1978), ”industrial water pollution” addison-wesley publishing company, inc., usa, canada. 5 rao, c. s., (1994), “environmental pollution control engineering”, wiley eastern, second reprint, india 6 sawyer, c. n. and mcgarty, p. l., (1978), “chemistry for environmental engineering”, 3 rd ed., mcgraw-hill, new york. iraqi journal of chemical and petroleum engineering vol.9 no.4 (december 2008) 16 issn: 1997-4884 separation of hexane-benzene mixtures by emulsion liquid membrane. adil a. al hemiri * and muhammad d. al zaidi. * chemical engineering department college of engineering university of baghdad – iraq abstract the effect of operating parameters on the batch scale separation of hydrocarbon mixture (benzene and hexane) using emulsion liquid membrane technique is reported. sparkleen detergent was used as surfactant and heavy mineral oil as solvent to receive the permeates. from the experimental results, the parameters that influenced the permeation are, composition of feed, contact time with solvent, ratio of volume of solvent to volume of hydrocarbon feed, ratio of volume of surfactant solution to volume of hydrocarbon feed, surfactant concentration, mixing intensity and glycerol as polar additive in the surfactant solution to eliminate drop breakup. the best conditions for the separation in this study were found to be: composition of feed (mole fraction of benzene=0.5245), contact time of 10min. , ratio of volumes of solvent to feed equal 3.5 , ratio of volumes of surfactant solution to feed of 0.4, surfactant concentration of 1wt%, mixing intensity equal 1000rpm and 70% by weight of polar additive. these conditions gave a separation factor of (8.0). keywords: liquid membrane, hydrocarbon separation, hydrocarbon permeation, emulsion liquid membrane. introduction membranes have been developed which made separation process within range of being economically and technically feasible. liquid membrane extraction was introduced as an alternative separation technique to the liquid –liquid extraction and to the separation by means of solid polymeric membranes. on the other hand, liquid membrane was first suggested in 1968 by li. liquid membranes are generally formed by first making an emulsion of two immiscible phases and then dispersing the emulsion in a third phase (continuous phase). emulsion liquid membrane (elm) is effective in separation hydrocarbon of different kinds, including these similar in their physical and chemical properties. it is a film composed of surfactants and their solvent. the film consists of water and one or more water soluble surfactant. this kind of film serves two purposes in a process of separating hydrocarbon. first, it permits selective permeation by one or more components of the feed. second, it keeps the hydrocarbon feed from mixing with a solvent used to carry away the permeates. furthermore liquid membrane is a film formed at an oil / water interface by a surfactant solution .such films are formed by dispersing the solution to be separated in the form of droplets in a surfactant solution .the droplets covered with an organic solvent phase received the permeates .during this process one of the components of mixture transfers from the droplets through the liquid membrane and into the organic solvent at a faster rate than the other .the organic solvent becomes rich in the more permeable component, and the droplets become rich in the less permeable component , thus achieving a separation of the component (15). where, the separation factor is a parameter to evaluate the process efficiency with respect to distillation process: separation factor = hexaneoftcoefficienondistributi benzeneoftcoefficienondistributi university of baghdad college of engineering iraqi journal of chemical and petroleum engineering phaseemulsionincontainedmixtureinhexaneoffractionmole productpermeatedinhexaneoffractionmole phaseemulsionincontainedmixtureinbenzeneoffractionmole productpermeatedinbenzeneoffractionmole separation of hexane-benzene mixtures by emulsion liquid membrane. 2 li (1971a) indicated that separation factor is a function of the solubility of permeate in water as well as the diffusivity of the permeate through the surfactant and water layers. also found that the separation of hydrocarbons is independent of surfactant concentration in the ranges from (0.001-0.1) wt%. li (1971b) studied the effect of glycerol on membrane life, permeation rate and separation factor. his results showed that 70 wt% of glycerol appear to be optimum concentration. also found that separation factor depends on solubility of permeates and its diffusivity. stelmaszek (1977) measured the equilibrium curves for benzene and hexane and studied the dependency of the separation coefficient of the mixture on the feed composition, flow rate, and the effect of the solvent flow rate on the volume fraction of hexane in the raffinate and permeate was determined. experimental work in the present study benzene and hexane mixture is separated with an aqueous solution of sparkleen detergent as the surfactant solution. it contains all sodium cations with 50 wt% sodium hexametaphosphate, 10 wt % sodium alkyl benzene sulphonate as anionic surfactant and 0.5 wt % as nonionic surfactant. it also contains 39.5 wt % sodium carbonate and sodium bicarbonate as ph buffering agents. the heavy mineral oil as the organic phase to receive the permeates. in this study the effectiveness of the liquid membrane technique to separate the hydrocarbon mixture as compared to fractional distillation was investigated. in addition, the investigation also included studying the effects on separation factor of several process variables, such as composition of feed, contact time with solvent, ratio of volume of solvent to volume of hydrocarbon feed, ratio of volume of surfactant solution to volume of hydrocarbon feed, concentration of surfactant, mixing intensity between solvent and emulsion and glycerol as polar additive to eliminate drop breakup. when the effect of one of variable was studied all the other variables were kept constant. procedure mixtures of benzene and hexane were prepared by mixing the required volumes of components by using a pipette to measure volumes. then the mixture was emulsified in an aqueous phase composed of sparkleen detergent and water. the mixer for emulsification of this mixture is a cylindrical vessel equipped with four baffles. a variable steady speed impeller with four blades is used for mixing. the mixture of benzene and hexane was stirred at low speed while the required quantity of surfactant solution is slowly poured into the mixer. after the emulsion is formed, the emulsion was mixed with the solvent, (heavy mineral oil), for the desired length of time. the mixer for contacting the emulsion with solvent is a jar test with two blade steel impeller with 50rpm to ensure uniform contact between the solvent and the emulsion, as shown in figure(1). as the system is agitated, permeation proceeds out of the droplets, through the aqueous film into the bulk solvent (heavy mineral oil). since benzene permeates more rapidly through the aqueous liquid membrane than hexane, the residual mixture in the emulsion will be gradually depleted in hexane, while the heavy mineral oil becomes enriched in this constituent. after contacting the emulsion with solvent, the solution was transferred to a separator funnel where it was allowed to separate. the mixture of solvent and emulsion separated into three layers in the separator funnel. the upper layer containing the emulsion composed of the surfactant solution and that portion of the mixture of benzene and hexane that did not permeate in the solvent. the middle layer composed of the solvent, heavy mineral oil, containing the permeate mixture of benzene and hexane. finally the bottom layer consisted of aqueous surfactant solution which had not entered the emulsion phase or surfactant solution resulting from droplet breakup. in this study the effect of polar additive was studied by using glycerol to eliminate drop breakup in the solvent. the range for glycerol content was from (10-70) wt% in the emulsion. the recovery of mixture of benzene and hexane from the solvent was carried out by simple distillation. the boiling point of the solvent was greater than 110 0 c where the boiling point of benzene and hexane was less than 81 0 c; therefore, if the distillation is carried out at temperature between 110 0 c and 81 0 c, essentially all benzene and hexane will evaporate leaving the solvent. the recovery of mixture of benzene and hexane from the emulsion phase was carried out by physical method; i.e. by the addition of 0.3 m nacl to the mixture will break the emulsion into two layers. the upper layer contains the mixture of benzene and hexane. the bottom layer contains the surfactant solution. the composition of the mixture of benzene and hexane is determined by measuring the refractive index of the mixture with the abbe a60 refractometer. a calibration curve relating the refractive index and percent composition was prepared and used to determine the composition of unknown mixtures. adil a. al hemiri and muhammad d. al zaidi ijcpe vol.9 no.4 (december 2008) 3 fig.1 schematic diagram of operation. results and discussion effect of mole fraction of benzene in feed on separation factor. figure (2) shows the effect of mole fraction of benzene(0.1-0.9) on separation factor. also figure (3) relates the composition of benzene in permeated product and in the feed. it can be seen that both the separation factor and permeate composition vary with feed composition. this is owing to the dependency of membrane structure and thickness on the nature of feed. li (1971) refers to the fact that the permeation of the molecule through the membrane depends upon the solubility of the molecule in the membrane and the diffusivity of this molecule through the membrane. from this fact, if we say that the only the solubility factor effect the separation, this leads us to that the separation factor is independent of feed composition and this is not reasonable with the results in the figures. on the other hand, if we consider only the diffusivity factor to effect the transfer and hence the separation, then the separation factor changes with feed composition to give constant permeate concentration. as a result from these facts and the data in figures (2) and (3) it can be said that both the solubility and diffusivity are important in this case. benzene is more permeable than hexane in water about (187.5) times, therefore, it is more permeable than hexane through the liquid membrane due to the solubility. this results is analogous to the results that obtained by stelmazak. figure (4) shows the vapor liquid equilibrium for benzene and hexane. from figures (3) and (4), it can be seen that the emulsion liquid membrane separation is the best for benzene-hexane mixture separation. fig. 2 effect of mole fraction of benzene on separation factor. fig. 3 relationship between mole fraction of benzene in feed and solvent. fig. 4 vaporliquid equilibrium curve (benzene/hexane) y: vapor phase mole fraction of benzene in hexane x: liquid phase mole fraction of benzene in hexane mole fraction of benzene s e p a r a ti o n f a c to r 0 1 2 3 4 5 6 7 8 0.0 0.2 0.4 0.6 0.8 1.0 mole fraction of benzene in feed m o le f ra c ti o n o f b e n z e n e i n s o lv e n t 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0.0 0.2 0.4 0.6 0.8 1.0 x y 0.0 0.2 0.4 0.6 0.8 1.0 0.0 0.2 0.4 0.6 0.8 1.0 separation of hexane-benzene mixtures by emulsion liquid membrane. 4 effect of contact times of emulsion with solvent on separation factor. figure (5) shows the effect of contact times on separation factor. from the figure we see that for short contact times the separation factor attains high values but decreases with increasing contact times until there is no separation. the maximum value obtained for separation factor occurs at contact time of about 10 minutes. this result is analogous to that of li (1971). the low values of separation factor for short contact times are due to that the emulsion of the mixture of benzene and hexane with sparkleen surfactant under the conditions of the experiment such that some of the mixture of benzene and hexane is not emulsified. thus when the emulsion is contacted with the solvent, the mixture that not emulsified pass immediately into the solvent without separation and leads to a low value of separation factor. as the contact time increases, the solvent phase becomes rich in benzene, therefore, the separation factor increases. the decrease in values of separation factor is due to the following reasons: the stability of the emulsion is limited then the emulsion will break allowing all of the benzene and hexane to go into the solvent, and the drops become rich in hexane and lean in benzene which result in an increase in the transfer rate for hexane because of the concentration gradient , which will reduce the separation factor. conclusions from the present study of using ann in predicting the bubble size in the homogenous region in fig. 5 effect of contact times on separation factor. effect of ratio of solvent to volume of hydrocarbon feed figure (6) shows the effect of ratio of solvent to feed on separation factor. it can be seen that the separation factor is low for relatively small volumes of solvent. as the relative volume of solvent increases, the separation factor increases and reaches a maximum at a ratio of (3.5). the low values of separation factor is because the droplets are close together in the solvent, therefore, the drops are more likely to coalesce. this process reduces the total surface area for mass transfer. for large volumes of solvent the separation factor decreases. this decrease is due to the fact that for both components the overall driving force (i.e. the difference of the concentration of the components between the drops and the solvent) increases where the droplets are more dispersed, resulting in nearly equal transfer rates for both benzene and hexane. fig. 6 effect of ratio of volume of solvent to volume of hydrocarbon feed on separation factor. effect of ratio of volume of surfactant solution to volume of hydrocarbon feed because the volume of surfactant solution is related directly to the droplet size and membrane thickness, the separation factor for separating benzene and hexane depends on the relative volumes of surfactant solution and feed. for a particular volume of feed, there is likely some minimum quantity of surfactant solution necessary to form a stable emulsion. if the amount of surfactant solution is less than the minimum, the separation factor is low because not all of the droplets of the mixture of benzene and hexane is covered with liquid membrane. it is expected that for large volumes of surfactant solution, the separation factor does not change (li, 1968). figure (7) shows experimental results for this ratio. it can be seen that separation factor is constant when the volume ratio approximately 0.4. contact time(min.) s e p a r a ti o n f a c to r 4.8 5.0 5.2 5.4 5.6 5.8 6.0 0 4 8 12 16 20 24 28 ratio of volume of solvent to volume of hydrocarbon feed s e p a ra ti o n f a c to r 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 adil a. al hemiri and muhammad d. al zaidi ijcpe vol.9 no.4 (december 2008) 5 fig. 7 effect of ratio of volume of surfactant solution to volume of hydrocarbon feed effect of surfactant concentration li (1971) found that the separation factor is independent of surfactant concentration from (0.001-0.1) wt%. figure (8) shows the experimental work for the relation between separation factor and surfactant concentration. the results show that separation factor is low for low concentration of surfactant, and then increases as surfactant concentration is increased. at about 1 wt% surfactant concentration, the separation factor is maximum, then for higher concentration of surfactant, the separation factor decreases. at low surfactant concentration, there are related fewer molecules of surfactant in the membrane surrounding the droplets, therefore, in the absence of enough surfactant molecules in the membrane, there is greater chance for breaking of the membrane that result in low values of the separation factor. the decrease in separation factor at higher surfactant concentration because that at higher surfactant concentration there are enough molecules in the membrane around the droplets to make the membrane more stable, but when the surfactant concentration is high, there is less water in the membrane. because the transfer of permeate through the membrane depends in part on the solubility of the material in the water, the transfer of these are decreased. and this leads to decreasing the separation factor at higher surfactant concentration. also the resistant of surfactant molecules in the membrane increases with increased surfactant concentration at higher values this leads to a decrease in the transfer rates of material through the membrane thus decreasing the separation factor. fig. 8 effect of surfactant concentration on separation factor. effect of mixing intensity figure (9) shows the effect of mixing intensity of emulsion on separation factor. it can be noticed that the separation factor increases with increasing mixing intensity up to 1000 rpm where the separation factor becomes constant. depending on the surfactant used, some of the drops might breakup in the solvent phase due to rupture of weak membrane; therefore, the separation factor will decrease for low mixing intensity. but for increasing gradually the mixing intensity the emulsion becomes more stable than for low mixing intensity because drop diameters of emulsion decrease, that also improved the permeation rate due to the increasing of surface area for mass transfer. it can be seen that above 1000rpm the separation factor becomes almost constant. this is due to the fact that the droplets reach diameters that do not change at higher mixing intensity. the higher mixing intensity does stabilize the emulsion but does not eliminate drop breakup. fig. 9 effect of mixing intensity on separation factor. ratio of volume of surfactant solution to volume of hydrocarbon feed s e p a ra ti o n f a c to r 2 3 4 5 6 7 8 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 concentration of surfactant s e p a ra ti o n f a c to r 1 2 3 4 5 6 7 8 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 mixing intensity (rpm) s e p a ra ti o n f a c to r 4.6 5.0 5.4 5.8 6.2 6.6 7.0 7.4 0 200 400 600 800 1000 1200 1400 separation of hexane-benzene mixtures by emulsion liquid membrane. 6 effect of glycerol as polar additive on separation factor figure (10) shows the effect of glycerol as polar additive to strengthen the surfactant membrane resulting in substantial elimination of drop breakup in the solvent phase and marked increase in separation factor. adding glycerol to a membrane increase the water layer viscosity. increasing gradually the percentage of glycerol will increase the values of separation factors. the reasons for this, is that for low values of glycerol added the rate of drop breakup is more than for high values of glycerol added up to 70% percent. after this percentage the surfactant layer becomes too viscous. the decrease for permeation rates of components can be controlled by increasing time to permeate. these results are analogous to that found by li (1971) and for li (1971) for that the optimum percentage for polar additives is 70wt%. fig. 10 effect of glycerol as polar additive on separation factor. conclusions 1. the increase in mole fraction of benzene in feed caused an increase in the separation factor up to mole fraction of benzene of 0.5245, and then the separation factor decreases with the increase of mole fraction. 2. the separation factor increases with increasing contact time up to contact time of about 10 min. and then decreased with increasing time of contact. 3. the increase in ratio of volume of solvent to volume of feed caused an increase in separation factor up to ratio of 3.5, then the separation factor decreases with the increase of the ratio. 4. the separation factor increases as the ratio of volume of surfactant solution to volume of feed increased up to 0.4, then the separation factor is essentially constant. 5. as the surfactant concentration is increased the separation factor increases up to concentration of (1.0wt %), then the separation factor decreases with further increase in surfactant concentration. 6. the increase in mixing intensity caused an increase in separation factor up to 1000 rpm then the separation factor is approximately constant. 7. glycerol is used as polar additive to eliminate drop breakup in solvent. the separation factor increased with the increase in weight percent of glycerol in surfactant solution up to 70%wt. further increase in weight percent of glycerol make the liquid membrane is so viscous that no separation can be achieved. references 1. hala, e., wichterle, i. polka. and boublik, t., 1968, "vapor liquid equilibrium data at normal pressures", britain, first edition. 2. kralj, d. and brecevic, l., (1998), "precipitation of some slightly soluble salts using emulsion liquid membrane ", croatia chemical act, vol. 71, p.p. (1049). 3. li, n.n, somerset and en's, (nov., 12, 1968) "separation of hydrocarbon with liquid membrane", u.s.pat, 3 410 794. 4. li, n.n, (1971) "permeation through liquid surfactant membranes", aiche, vol. 17, p.p. (459). 5. li, n.n, (1971), "separation of hydrocarbon by liquid membrane permeation", ind.eng.chem.process.des.develope, vol.12, p.p. (215). 6. mcauliffe, c., (1986) "solubility in water of paraffin, cycloparraffin, olefin, acetylenes, cycloolefins and aromatic hydrocarbons", j.phys.chem. vol.70, p.p. (1267). 7. stelmaszek, j., (1977), "separation of liquid mixtures by liquid membranes in a column apparatus", j.memb.sci, vol.2, p.p. (197). 8. ward, w.j, (1970), "analytical and experimental studies of facilitated transport ", aiche vol. 16, p.p. (405). glycerol wt% s e p a ra ti o n f a c to r 7 8 9 10 11 12 13 14 15 16 0 10 20 30 40 50 60 70 80 iraqi journal of chemical and petroleum engineering vol.18 no.3 (september 2017) 49 58 issn: 1997-4884 synthesis and characterization of tri-composite activated carbon nada s. ahmedzeki a , salah m. ali b and sarah r. al-karkhi a a chemical engineering department, baghdad university, baghdad – iraq b petroleum research and development center, baghdad – iraq abstract activated carbon loading with metals oxides is new adsorbents and catalyst, which seem very promising for desulfurization process. the present study deals with the preparation of three metals oxides loaded on activated carbon (ac). the tri composite of zno/nio/coo/ac was characterized by x-ray diffraction (xrd), x-ray florescence (xrf), n2 adsorption for bet surface area, pore volume and atomic force microscopy (afm). the effect of calcination temperature is investigated. the best calcination temperature is 250 o c based on the presence of phase, low weight loss and keep at high surface area. the surface area and pore volume of prepared tri composite are 932.97m 2 /g and 0.6031cm 3 /g respectively. the average particle size of tri-composite is 104.72 nm. results confirmed a successful route for preparing the composite with promising characteristics. key words: activated carbon; loading; characterization, calcination introduction activated carbon (ac) is one of the most known adsorbents due to its nature porous structure that have high surface area, large pore volume and its activity, due to this specific characteristics activated carbon can be used as adsorbent, catalyst and catalyst support for the removing different types of compounds [1] in addition activated can be regeneration for more than four times [2]. it was found that activated carbon was the best adsorbent between the activated alumina and nickel-silica alumina to remove model sulfur compounds. hydrothermal technique is one of the best methods to produce pure fine oxide powders. roy and somya (2000) presented many methods like; hydrothermal decomposition, hydrothermal metal oxidation, hydrothermal reaction, hydrothermal precipitation and hydrothermal hydrolysis, hydrothermal electrochemical, reactive electrode submerged arc, hydrothermal microwave, and hydrothermal sonochemical. the ideal powders could be defined as the powders having the ultimate pronounced properties. some of these are, particle size of nano or micro size, soft or no agglomeration, narrow particle size distribution, spherical shape, having good morphology, controllable chemical composition, university of baghdad college of engineering iraqi journal of chemical and petroleum engineering synthesis and characterization of tri-composite activated carbon 50 ijcpe vol.18 no.3 (sep. 2017) -available online at: www.iasj.net uniform microstructure and good crystallinity [3]. the problem of use the activated carbon in desulfurization process is it selectivity, the nature of activated carbon surface is hydrophobic, and can be adsorbed aromatic hydrocarbons that have the same structure of cyclic sulfur compound, since has been suggested the oxidation process to convert sulfides (not polar compounds) to sulfones (more polarity compounds) with reactive adsorption to enhances selectivity of sulfur compounds rather than other aromatic compounds with further improvement to increase the selectivity of activated for adsorption of cyclic sulfur compound was incorporated with metal oxides. there are more researches for improvement activated carbon such as loading with metal oxide where this can increase the sulfur removal, since reactive adsorption by use metal oxides on the support activated carbon, the πelectron interactions where cycle sulfur compound interact with metals oxide on the catalyst support activated carbon. the improvement of selectivity of activated carbon surface to adsorbed cyclic sulfur compounds (dbt and 4,6-dmdbt) for model diesel fuel with sulfur content 20 ppm at ambient conditions studied in packed bed column by deposited metal species like silver, nickel and cobalt, finding the metal enhance the sulfur removal, and cobalt supported with activated carbon is more active than silver [4]. the activity of activated carbon loaded with copper oxide and nickel oxide examined, the conclusion that the copper or nickel made the specific site more active for adsorption of sulfur compounds and it is more efficient than activated carbon surface alone, this can be explained by πinteraction and acid-base interaction between metal species and sulfur compounds, that convert at surface of active site then adsorbed on activated carbon surface [5]. the activated carbon and metals oxides composites prepared by thermal co-precipitation and examined its activity with sulfur compounds such as thiophene, benzothiophene and dibenzothiophene, and founded that metals oxides enhanced the interaction with sulfur compounds [6]. the employed of carbon nanotube, graphene oxide and activated carbon, investigated loaded with aluminum oxide at the loading ratio of 18.8% and 9% as adsorbents for dbt that dissolved in n-hexane as model diesel fuel with sulfur continent 250 ppm at 25 o c, 200 rpm shaking speed with 2 h contact time in batch experiment, the highest removal of dbt near 98% for model fuels and 30% for real fuels at higher concentration was achieved using the activated carbon loaded the aluminum oxide with loading ratio of 9%, and bet surface area 825 m 2 /g with pore volume 0.39 cm 3 /g [2]. the adsorption of benzothiophene sulfone and dibenzothiophene sulfone dissolved in toluene with sulfur content 500 ppm for model diesel fuel studied by employing granular activated carbon supported with metal oxide (nickel oxide, iron oxide (iii) and copper oxide) in batch process at room temperature and 120 rpm agitation speed, the highest activity of metal oxide to adsorbed benzothiophene sulfone founded for iron oxide 71.9% and the lowest for nickel oxide 65.4%, whereas for dibenzothiophene sulfone, highest removal for nickel oxide 99% and lowest for copper oxide 98.3%. [7]. it was found that activated carbon was the best adsorbent between the activated alumina and nickel-silica alumina to remove model sulfur compounds. nada s. ahmedzeki, salah m. ali and sarah r. al-karkhi -available online at: www.iasj.net ijcpe vol.18 no.3 (sep. 2017) 51 hydrothermal technique is one of the best methods to produce pure fine oxide powders. roy and somya 2000 presented many methods like; hydrothermal decomposition, hydrothermal metal oxidation, hydrothermal reaction, hydrothermal precipitation and hydrothermal hydrolysis, hydrothermal electrochemical, reactive electrode submerged arc, hydrothermal microwave, and hydrothermal sonochemical. the ideal powders could be defined as the powders having the ultimate pronounced properties. some of these are, particle size of nano or micro size, soft or no agglomeration, narrow particle size distribution, spherical shape, having good morphology, controllable chemical composition, uniform microstructure and good crystallinity [3]. the aim of present work was prepared and characterized tri-metals oxides loaded on activated carbon surface and examined the best calcination temperature. experimental materials the materials compounds which are used are activated carbon was supplied by thomas baker/india, table 1 list the properties of activated carbon. zinc nitrate hexahydrated zn(no3)2.6h20 with purity 98% was supplied by thomas baker, india and sodium hydroxide with purity 99% pellets was supplied by hopkin and williams, england nickel nitrate hexahydrated ni(no3)2.6h20 with purity 99.7% was supplied by fisher certified, cobalt nitrate co(no3)2 was supplied by panreac, espana and kerosene with sulfur content 2850 ppm was supplied by the midland refineries company/al-dura refinery. table 1, properties of ac property value ph for ac dispersed in deionization water 5-7 real density, g/cm3 2.5841 bulk density, g/cm3 0.2662 porosity εp 0.89 procedure of preparation zinc oxide, nickel oxide and cobalt oxide loaded on activated carbon was prepared by co-precipitation method. 10g of activated carbon we added 0.4917 g, 0.4917 g and 0.5382 g of zinc nitrate hexahydrated, nickel nitrate hexahydrate and cobalt nitrate respectively to obtain ≈ 3 wt.% loading for each oxide. first activated carbon is dried in furnace for 1 h at 200 o c, and then 10 g of activated carbon powder was dispersed in 250 ml deionized water for best dispersion. the solution of activated carbon and deionized water was mixed by putting a magnetic stir bar with magnetic stir plate for 12 h. weighted a 0.4917 g of zinc nitrate hexahydrate and dissolved in 20 ml water, weighted 0.4917 g of nickel nitrate hexahydrate and dissolved in 20 ml water and also weighted 0.5382 g of cobalt nitrate and dissolved in 20 ml water. then addition zinc nitrate solution by drop wise in dispersed activated carbon and water followed by adding nickel nitrate solution and cobalt nitrate solution while stirring the mixture, the ph of mixture is ≈ 5.7. synthesis and characterization of tri-composite activated carbon 52 ijcpe vol.18 no.3 (sep. 2017) -available online at: www.iasj.net the ph of the mixture adjustment by adding 1m of naoh solution until the ph reaches to 8. heating the mixture for 6 h at 90°c with reflux and under mixing, followed by filtration, washing, drying overnight at 110°c and calcination the product for 3h at different calcination temperatures (150-350 o c). results and discussion characterization of tri-composite the xrd patterns of the activated carbon, showed the peaks between 2θ= 20-30 and 40-50, which are noisy and disordered indicating the amorphous carbon as shown in figure 1. for ac/zno/nio/coo, the clear peaks at 2θ =31.748°, 34.438°, 36.249°, 47.539°, 56.551°, 62.856°, 67.912°, 69.052°, 72.604° and 76.950° indicates to crystalline zno, and at 2θ = 37.278, 43.295, 62.913, 75,439, and 79.387 indicate to crystalline nio, and at 2θ = 42.644°, 49.662°, 72.864° indicate to crystalline coo as shown in figure 2 and noisy background patterns refer to amorphous carbon. fig. 1, xrd pattern of activated carbon fig. 2, xrd pattern of tri-composite the xrf analysis shows the metal oxide composition for metals oxides loading on the surface of the activated carbon. a total measured metals oxides for each composite was ≈ 10 wt. %. the loading ratio was chosen 10wt % because the increasing in loading ratio causes the block of pore, and leads to decrease of surface area [8]. the average particles diameter was determined by afm. table 2 list the particles size distribution of activated carbon and prepared composites. the increasing in particle size causes the decrease in the surface area. figure 3 was showed topographical surface images of activated carbon and its composites in two dimensional (2d) and three dimensional (3d) were obtained from afm analysis. table 3 shows the results of afm measurements. the most important parameters in afm are the average roughness, root mean square roughness, surface skewness and surface kurtosis. the results indicated that the tri-composite is roughness than activated carbon because of the mechanism of nucleation. nada s. ahmedzeki, salah m. ali and sarah r. al-karkhi -available online at: www.iasj.net ijcpe vol.18 no.3 (sep. 2017) 53 the results show that both activated carbon and tri-composite have negative surface skewness (rsk<0：skewed upward relative to the average line) which means that surface has more valleys than peaks. the results show also that both activated carbon and tricomposite have surface kurtosis are lower than 3 (rku<3：the height distribution is not sharp) indicating a flat surface (platykurtic) [9, 10]. table 2, particle size distribution composite type avg. diameter [nm] ≤ 10vol % [nm] ≤ 50vol % [nm] ≤ 90vol % [nm] ac 93.84 50 90 140 tricomposite 104.72 70 100 130 (a) ac surface 2d (b) ac surface 3d (c) tri-composite surface 2d (d) tri-composite surface 3d fig. 3, afm of ac and tri-composite surfaces 2d and 3d synthesis and characterization of tri-composite activated carbon 54 ijcpe vol.18 no.3 (sep. 2017) -available online at: www.iasj.net table 3 afm roughness analysis measurements roughness (2d) parameter activated carbon tricomposite amplitude parameter maximum height of the roughness profile (rz) 6.21 nm 5.59 nm average roughness (ra) 1.17 nm 1.79 nm root mean square deviation of the roughness profile (rq) 1.42 nm 2.14 nm skewness of the roughness profile (rsk) -0.315 0.552 kurtosis of the roughness profile (rku) 2.43 2.37 hybrid parameters root mean square slope of the roughness profile (rδq) 0.0711 nm -1 0.138 nm -1 surface area ratio (rdr) 0.248 0.918 functional parameter surface bearing index (sbi) 2.38 8.17 core fluid retention index (sci) 1.38 1.2 reduced summit height (spk) 0.545 0 core roughness depth (sk) 3.8 nm 5.32 nm reduced valley depth(svk) 1.54 nm 2.65 nm height interval of bearing curve (sdc) (0-5)% 0.607nm 0.263nm (5-10)% 0.328nm 0.246nm (10-50)% 1.64nm 2.22nm (50-95)% 2.79nm 4.45nm spatial parameter fractal dimension 2.55 2.48 calcination temperature study the influence of calcination temperature on the weight of activated carbon loss as well as the existence of phases has been studied. the vacuum condition or n2 space is perfect to flash out air, since they prevent carbon from weight loss in the combustion as seen in equation (1). … (1) the selection of the calcination temperature ranges between 150-350 o c according to the previous studies. figure 3 shows tga curves of ac and fe2o3/ ac [11]. figure 4 tga curves of ac and ac/fe2o3[11] nada s. ahmedzeki, salah m. ali and sarah r. al-karkhi -available online at: www.iasj.net ijcpe vol.18 no.3 (sep. 2017) 55 as shown in figure 4 the activated carbon is thermally stable up to 550 o c, while the fe2o3/ac began to burn approximately at 350 o c. also, the presence of nitrogen was beneficial for both materials because they were more stable reaching temperatures higher than 600 o c. by considering these findings, the effect of calcination temperature on zno/nio/coo/ac was studied. 5 g of ac/zno/nio/coo was taken and calcinated at different temperatures ranged between 150-350 o c, and weighted after calcination as listed in table 4. table 4, weight loss and surface area at different calcination temperature temperature o c wt% surface area m 2 /g 3h calcination 150 98.35 839.709 200 36.73 881.116 250 29.88 604.6587 300 21.61 345.0581 350 18.92 299.218 the surface area decreases as a result of the loss of activated carbon and the increase of loading metals oxides. to select the best calcination temperature, the phases must be checked in addition to the decrease in surface area. therefore, by examining figures 5 to 7 for the xrd pattern at different calcination temperature it was concluded that the best calcination temperature is 250 o c. the surface area and pore volume of prepared tri composite at best calcination temperature for 10g sample were measured by bet method, the resulted values of surfaces area and pore volume listed in table 5. table 5, surface area and pore volume ac tri-composite surface area m 2 /g 1005.5 932.98 pore volume cm 3 /g 0.6203 0.6031 the surface area of activated carbon after loading of ≈10wt % metals oxides still high and near from the values of original source, and sometimes the surface area and pore volume increase or still the same or near from original source in case loading ratio less or equal 10 wt. % , this due to good dispersion of the metals oxides [12]. fig. 5, xrd test of at calcination temperature 350 o c synthesis and characterization of tri-composite activated carbon 56 ijcpe vol.18 no.3 (sep. 2017) -available online at: www.iasj.net fig. 6, xrd test of at calcination temperature 300 o c fig. 7 xrd test of at calcination temperature 250 o c activity of tri-composite the activity of tri-composite is examined for oxidation desulfurization of iraqi kerosene fuel with sulfur content 2850 in bench scale at ambient conditions (6.25g zno/nio/coo/ac, 25 o c and 40 min) using oxygen gas, the samples was test after filtered from composite. the oxidation desulfurization experiments were carried out in 500 ml flask; oxygen gas was bubbled at constant flow rate. the sulfur content of kerosene filtered was determined according to astm d7039 in the petroleum research and development center / ministry of oil by using the testing device (sulfur analyzer, sindie otg, usa). the total sulfur content determined is 2008 ppm, the sulfur removal percent 29.54%, the percent removal of sulfur compounds was calculated using equation (2). … (2) conclusions the best calcination temperature is 250 o c; it was checked with crystal phase, weight loss and surface area. the observation by atomic force microscopy in both surface morphology and surface growth characterization shows the tricomposite is roughness than activated carbon because of the mechanism of nucleation; both activated carbon and tri-composite have more valleys than peaks in their surfaces and both activated carbon and tri-composite nada s. ahmedzeki, salah m. ali and sarah r. al-karkhi -available online at: www.iasj.net ijcpe vol.18 no.3 (sep. 2017) 57 have a flat surface. the particle size distribution for tri-composite: ≤ 10 vol. % 70 nm; ≤ 50 vol. % 100 nm and ≤ 90 vol. % 130 nm. the surface area and pore volume of prepared tri composite are 932.97m 2 /g and 0.6031cm 3 /g respectively. the oxidation desulfurization of iraqi kerosene fuel using oxygen gas and tricomposite gives 29.54% sulfur removal. nomenclature greek letters θ scattering or bragg angle εp porosity of the composite particles notations symbol definition units c0 initial sulfur compounds concentration ppm ct sulfur compounds concentration at any time ppm abbreviations ac activated carbon zno/nio/coo/a c zinc oxide /nickel oxide/cobalt oxide/activated carbon afm atomic force microscope astm american standard test method bet beunauer, emmett and teller dbt dibenzothiophene 4,6-dmdbt 4,6dimethyldibenzothiophe ne ods oxidation desulfurization icdd international center for diffraction data tga thermal gravimetric analysis xrf xray florescence xrd x-ray diffraction references 1e. ahumada, h. lizama, f. orellana, c. suárez, a. huidobro, a. sepúlveda-escribano, and f. rodríguez-reinoso, “catalytic oxidation of fe(ii) by activated carbon in the presence of oxygen. effect of the surface oxidation degree on the catalytic activity,” carbon n. y., vol. 40, no. 15, pp. 2827–2834, 2002. 2m. k. nazal, m. khaled, m. a. atieh, i. h. aljundi, g. a. oweimreen, and a. m. abulkibash, “the nature and kinetics of the adsorption of dibenzothiophene in model diesel fuel on carbonaceous materials loaded with aluminum oxide particles,” arab. j. chem., 2015. 3s. somiya and r. roy, “hydrothermal synthesis of fine oxide powders,” bull. mater. sci., vol. 23, no. 6, pp. 453–460, 2000. 4m. seredych and t. j. bandosz, “adsorption of dibenzothiophenes on activated carbons with ag, co and ni deposited on their surfaces,” energy and fuels, vol. 23, pp. 3737–3744, 2009. 5e. s. moosavi, s. a. dastgheib, and r. karimzadeh, “adsorption of thiophenic compounds from model diesel fuel using copper and nickel impregnated activated carbons,” energies, vol. 5, no. 10, pp. 4233– 4250, 2012. 6k. alhooshani, a. a. r., t. a. saleh, and m. n. siddiqui, “methods for preparing composites of activated carbon / zinc oxide and activated carbon / zinc oxide / nickel oxide for desulfurization of fuels,” 20150148581 a1, 2015. 7t. chen, m. l. agripa, m. lu, and m. l. p. dalida, “adsorption of sulfur compounds from diesel with ion-impregnated activated carbons,” energy & fuels, 2016. synthesis and characterization of tri-composite activated carbon 58 ijcpe vol.18 no.3 (sep. 2017) -available online at: www.iasj.net 8j. chaichanawong, t. yamamoto, t. ohmori, and a. endo, “adsorptive desulfurization of bioethanol using activated carbon loaded with zinc oxide,” chem. eng. j., vol. 165, no. 1, pp. 218– 224, 2010. 9olympus ims, “roughness (2d) parameter | olympus ims.” 2016. 10m. raposo, q. ferreira, and p. a ribeiro, “a guide for atomic force microscopy analysis of soft condensed matter,” mod. res. educ. top. microsc., pp. 758–769, 2007. 11j. a. zazo, a. f. fraile, a. rey, a. bahamonde, j. a. casas, and j. j. rodriguez, “optimizing calcination temperature of fe / activated carbon catalysts for cwpo,” vol. 143, pp. 341–346, 2009. 12s. p. hernandez, m. chiappero, n. russo, and d. fino, “a novel zno-based adsorbent for biogas purification in h2 production systems,” chem. eng. j., vol. 176– 177, pp. 272–279, 2011. dr riyadh _mag_.doc ijcpe vol.8 no.4 (december 2007) 13 iraqi journal of chemical and petroleum engineering vol.8 no.4 (december 2007) 13 -17 issn: 1997 -4884 effect of feed concentration on the production of pregelatinized starch in a double drum dryer riyadh s. al-mukhtar chemical engineering department university of technology iraq abstract double drum dryer is operated for producing pregelatinized maize starches using feed starch slurries of different solids(7, 10 and13 g/100 g )content . steam pressure (2,3,and 4 bar), the level of pool between the drums (4,7,and 10 cm) , and speed of drums rotation (3,4,and 6 rpm) are varied together with the feed solids content in a practical range of values. the response of the dryer is registered by measuring several output variables, i.e. external drum temperature, product moisture content, mass flow rate. keywords: drum drying, pregelatinized starch, feed solids content. introduction the use of drum dryers is a common industrial practice for the production of a variety of foodstuffs such as yeast creams, fruit purees, baby foods, mashed potatoes, dry soup mixtures, pregelatinized starches, [1]. pregelatinized starches simply pre -cooked and dried are starches that readily dispersed in cold water to form stable pastes and are used mainly as thickeners in foods and as adhesives in the textile industry [2]. the boiling type of drying involved in drum drying makes pregelatinized starches be indeed very porous and easy to rehydrate, ready to use [3,4]. drum –drying results in specific physicochemical modification of the native starch due to the gelatinization and further solubilizatioin of the starch granules .the delivered products often referred to as pregelatinezed or instant starches are customarily in the form of thin solid sheets. these starches prepared in t wo consecutive stages : complete gelatinzation (to improve the nutritional value of starch ) and drying. both stages exploit the heat transferred from the surface of the steam-heated drums to the wet product. a double drum dryer consists of two counter rotating horizontal cylinders of equal diameters, fig. 1. the cylinders are hollow and are heated by steam condensing on their inside surface. one of the cylinders can be usually adjusted at right angles to its axis so that the gap between the two drums may be varied. the starch suspension is fed into the wedge-shaped space formed between the two drums (pool ) where it heats up and gelatinizes. the gelatinized starch is calendared into a thin layer as it passes through the gap forced by the rotary action of the closely spaced drums. right after the gap this layer splits into two films of gelatinized material, one for each drum. these films progressively dry as they rotate being adhered to the drums and are finally scraped off by blades extending the whole length of the drums. thus, drum dryers are essentially conduction dryers, the drying effect being obtained by the transfer of heat from the condensing steam through the metallic body of the cylinders to the film of the material covering the external surfa ce of the drums. a survey of the recent literature shows that studies dealing with double drum dryers are rather scarce and are mainly of technological orientation. e.g. [5]. it is recognized that the presence of two drums in double drum dryers dictates quite distinct operational characteristics and direct comparisons with single drum dryers are not possible. for instance, in single drum dryers mass flow rate and film thickness depend very little on steam pressure since the gap is chiefly university of baghdad college of engineering iraqi journal of chemical and petroleum engineering effect of feed concentration on the production of pregelatinized starch in a double drum dryer ijcpe vol.8 no.4 (december 2007) 14 determined by the adjustment of auxiliary rollers conversely, in double drum dryers steam pressure is a major parameter influencing gap width [3] there are four input variables involved in the operation of a double drum dryer for a fixed feed material: (a) steam pressure, (b) speed of drum rotation, (c) pool level between the drums and (d) condition of the feed material, i.e. concentration physical characteristics and temperature at which the material reaches the drum surface. the temperature around the inside surface of the drum is quite constant but always less than the temperature of the supplied steam. on the other hand the temperature at the outside surface of the drums is not constant and is a result of a combination of all operating conditions [5].. the purpose of this work is to investigate the effect of the different conditions of the feed material. among them, special attention is paid to the role of the solids content of the feed slurry on the performance of the drum dryer. for this, the interaction among all input variables and their relation with certain output variables of the dryer (product moisture, mass flow rate) is examined. materials and methods commercial native maize starch is purchased form alhashimya factory, with moisture content of 13.5 g/100 g. the total amylose content is 13.5g/100 g. native maize starch is modified by a double drum dryer (trocknungs anlagen ). the drums have 0.3m diameter and 0.3m length and are synchronously driven at 2, 3 or 4 rpm the drums are internally heated by steam at 7, 10 and13 g/100 g. the level of the free surface of the liquid pool between the two cylinders is regulated (manually) at 4, 7, or 10 cm above the gap. starch/water suspensions with solids concentration of 7, 10 and13 g/100 g (wet basis) are employed as the dryer feed this range of concentrations is selected in order to get good quality products given the range of the other input variables of the dryer.. the feed suspensions are prepared in a continuously agitated large tank (5 l) where from a rotary positive displacement pump drives them to the dryer. a uniform distribution of the starch feed over the whole pool area between the drums is achieved by letting the suspension pass through a perforated horizontal tube, running the length of the drums, and free fall into the space between the drums. the feeding of the dryer is done only after the drums have reached their final stable temperature after traveling 3/5 of a revolution, the dried product is removed in the form of thin sheets by the blades samples of the dry product are collected with the dryer operating at steady state. each experiment includes at least three measurements at every particular set, moisture content of the product sheets is determined by using the loss -in-weight technique. mass flow rate is measured by collecting and timing large amounts of product sheets as they come off the drums . results and discussion evaporation losses from the pool decrease substantially as the solids content of the slurry increases. it appears that the other (than the feed concentration) operating conditions of the dryer do not seriously affect the evaporation losses from the pool. for all the examined concentrations, at higher pool levels the free surface of the pool appears less disturbed by the boiling activity. the dry product sheets that are scraped off by the doctor knifes ,it is observed that feed slurries with higher solids content result in thicker and more humid products. for a 13 g/100 g slurry sometimes wetter zones appear randomly here and there on the product sheets. in all end products the granular shape of starch is completely absent. instead, the sheets look like a composite medium in which irregular air pockets are randomly distributed inside the continuous solid phase. effect of steam pressure vs. feed concentration in order to study the influence of the parameters on drum operation a reference local temperature is chosen; the one measured on the bare metallic surface of the drums just after the doctor blades. the same location was also chosen by[5], who observed that temperatures measured at this spot fluctuate less with time than temperatures obtained at other locations around the drums where the material is present. steam pressure has a direct influence on drum temperature increasing the steam pressure increases the inner and, consequently, the outer temperature of the drums. this effect is clearly seen from fig. 2 where runs conducted with a pool level of 7 cm and a speed of4 rpm are presented. clearly, the highest temperatures are observed for the more concentrated slurries. fig. 3 displays the variation of product moisture with steam pressure. increasing the steam pressure generally makes the moisture to decrease unless it is already low enough (7 g/100 g slurry). fu rthermore, the more the solids in the feed slurry the more the final product. fig. 4 shows the dependence of the total mass flow rate on steam pressure. the higher drum temperatures for the more concentrated slurries in fig. 2 (for fixed steam press ure) manifest a poorer external heat flux (drum-material). the fairly constant internal heat flux provided by the condensing steam inside the drums is only partly received by the material outside the drums, the other part is being used to rise the temperature of the drums which act as heat reservoirs. in this respect, two distinct contributions can be identified. one refers to the external heat flux from the drums to the material gelatinizing in the pool and the other to the material drying as a thin film after the riyadh s. al-mukhtar ijcpe vol.8 no.4 (december 2007) 15 gap. as regards the pool material, a reduction in heat flux might be expected due to the increased viscoelasticity of slurries with higher solids content which not only retards convective currents in the pool but also hinders the removal of vapor bubble screated by boiling on the drum surface. regarding film drying over the drums, at least three parameters must be taken into account: the transport properties, water activity and thickness of the material. a more moist starch gel has higher heat cond uctivity and moisture diffusivity. however, both properties are strongly related to the temperature and texture of the material. in particular, the role played by the progressively increasing porosity (void fraction) of the drying gel is a higher porosity means lower heat conduction but higher mass diffusion. this is so because air has lower heat conductivity than any liquid or solid but moisture transfer by vapor diffusion is much faster than by liquid/ solid diffusion at first glance fig. 2,3, and-4 imp lies that the lower production rate as steam pressure increases for feed concentrations of 10 and 13 g/100 g may be due to the higher temperature of the drums which can remove more moisture from the product. one must realize, however, that the temperature s in fig. 2 are indicative of the overall thermal condition of the drums . thus, a higher drum temperature corresponds to a narrower gap between the drums which can result in a smaller throughput rate. effect of pool level vs. feed concentration the level of the pool dictates both the volume of the slurry in the pool and also the contact area of the slurry with the drums, so it is directly associated with the heat delivered by the drums. the pool level also determines the residence time of the material in the pool, which dictates the degree of starch gelatinization and therefore the viscosity of the slurry . fig. 5 presents the effect of pool level on drum temperature. these tests are performed with a steam pressure of 3 bar and a drum speed of 4 rpm. generally, the temperature drops as the pool level goes up . this may be attributed to a higher boiling load with pool level: the temperature of the drums fall because of a higher heat flux from the wall towards the material. however, the higher temperatures observed in fig. 5 with the more concentrated slurries (for the same level) indicate that the transport properties of the material also influence the external heat flux of the drums. thus, for a more concentrated slurry the ability to convect and conduct heat from the outside surface of the drums to the material is deteriorated and so the temperature of the drums rises given the finite heat capacity of the drum walls. figure 6, and 7 displays the variation of product moisture, mass flow rate with pool level for the same runs as in fig. 5. moisture is not seriously affected by pool level for concentrations of 7 and10 g/100 g. in this case, it appears that the thermal capacity of the dryer is high enough regardless of the other parameters so as to permit comparable drying of the material. this is different for a 13 g/100 g slurry where the moisture cannot be adequately removed when the pool level increases but an increasing trend is observed with pool level. inspection of fig. 7 indicates that the flow rate and film thickness may only be partly blamed for this. from a practical point of view, at low pool levels, variations in feed concentration influence less the performance of the dryer. vice versa, operation with a feed concentration of 7 g/100 g is less sensitive to variations of pool level. it is also interesting that for a 10 g/100 g slurry rising the pool level to 13cm results in higher production rates with a virtually constant moisture effect of drum speed vs. feed concentration as the speed of rotation ascends the drum temperature descends, fig 8. the presented tests are conducted with a steam pressure of 3 bar and a pool level of 7 cm. the figure shows that , as throughput rate increases more heat is delivered by the drums where as thinner films result in higher heat fluxes, too. in addition, shorter drying periods (higher rpm) are associated with lower drum temperatures since there is not enough time for heat build-up in the drum walls. in fig. 9 the influence of drum rotation speed on the moisture of the final product is shown. a higher rotation speed generally causes wetter end products. it must be added though that the lower the feed concentration the smaller the influence of speed while at a concentration of 7 g/100 g practically no influence is observed because the material is too dry even for a 4 rpm speed. fig. 10 displays the variation of mass flow rate with rotation speed. here the dominance of concentration against speed of rotation is prominent. so for the higher feed concentrations(10 and 13 g/100 g) the present results show that the product outflow increases with speed.. the respective film thickness is essentially invariant among the examined rotation speeds (considering the statistical significance of the determination). fig. (1) : schematic representation of the employed double drum drier (trocknungs anlagen ). effect of feed concentration on the production of pregelatinized starch in a double drum dryer ijcpe vol.8 no.4 (december 2007) 16 fig (2): effect of steam pressure versus feed concentration on drum temperature, other experimental conditions pool level 7cm, drum speed 4rpm. fig (3): effect of steam pressure versus feed concentration on product moisture content, other experimental conditions pool level 7cm, drum speed 4rpm. fig (4): effect of steam pressure versus feed concentration on mass flow rate, other experimental conditions pool level 7cm, drum speed 4rpm. fig (5): effect of pool level versus feed concentration on drum temperature, other experimental conditions steam pressure 3bar, drum speed 4rpm. fig (6): effect of pool level versus feed concentration on product moisture, other experimental conditions steam pressure 3bar, drum speed 4rpm. fig (7): effect of pool level versus feed concentration on mass flow rate, other experimental condit ions steam pressure 3bar, drum speed 4rpm. 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0 4.2 steam pressure, bar 98 100 102 104 106 108 110 112 114 116 118 120 d ru m t e m p e ra tu re , c feed conc. 7g/100g feed conc. 10g/100g feed conc. 13g/100g 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0 4.2 steam pressure, bar 5 10 15 20 25 30 35 40 m o is tu re , g /1 0 0 g w .b feed conc. 7g/100g feed conc. 10g/100g feed conc. 13g/100g 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0 4.2 steam pressure 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 m a ss f lo w r a te feed conc. 7g/100g feed conc. 10g/100g feed conc. 13g/100g 3 4 5 6 7 8 9 10 11 pool level, cm 102 104 106 108 110 112 114 116 118 120 d ru m t e m p e ra tu re , c feed conc. 7g/100g feed conc. 10g/100g feed conc. 13g/100g 3 4 5 6 7 8 9 10 11 pool level, cm 5 10 15 20 25 30 35 40 m o is tu re , g /1 0 0 g w .b feed conc. 7g/100g feed conc. 10g/100g feed conc. 13g/100g 3 4 5 6 7 8 9 10 11 pool level, cm 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 m a ss f lo w r a te feed conc. 7g/100g feed conc. 10g/100g feed conc. 13g/100g riyadh s. al-mukhtar ijcpe vol.8 no.4 (december 2007) 17 fig (8): effect of drum speed versus feed concentration on drum temperature, other experimental conditions steam pressure 3bar, pool level 7cm. fig (9): effect of drum speed versus feed concentration on product moisture, other experimental conditions steam pressure 3bar, pool level 7cm. fig (10): effect of drum speed versus feed concentration on mass flow rate, other experimental conditions steam pressure 3bar, pool level 7cm. conclusions among the examined input variables (steam pressure, pool level, rotation speed and feed concentration) the concentration of the feed slurry appears to be more significant for the performance of the dryer. the effect of varying the steam pressure, pool level and rotation speed on the output variables is different at different feed concentrations. for a 7 g/100 g feed slurry the effect .is marginal while it becomes more pronounced as the concentration of the feed slurry increases. so for a 13 g/ 100 g slurry the product moisture, mass flow rate are the greatest regardless of the values of the other input variables. however, operating the dryer with a 13 g/100 g feed slurry often results in product sheets of uneven moisture. on the other hand, the less concentrated films dry easier but at much smaller product outflows. so from a practical point of view the 10 g/100 g slurry seems a reasonable compromise. the variation of mass flow rate with respect to the other input variables. the behavior of the dryer with 7 g/100 g slurry is quite different and appears to be satisfactorily described by a gravity-driven free flow of the material in the pool between the very thin in this case boundary layers around the drums. references 1. bonazzi, c., dumoulin, e., raoult-wack, a., berk, z., bimbenet, j. j., courtois, f., trystram, g. and vasseur, j. food drying and dewatering. drying technology, 14(9), 2135–2170 (1996) 2. collona, p., buleo, a. and mercier, c. physically modified starches. in: gaillard t. (ed.), starch: properties and potential, critical reports on applied chemistry, vol. 13.new york: john wiley, pp.79–114 (1987) 3. gardner, a. w. industrial drying. london: leonard hill books, pp. 220–242 (1971) 4. moore, j. g. drum dryers. in: mujumdar a. s. (ed.), handbook of industrial drying, 2nd edn., vol. 1. new york: marcel dekker, pp. 249–262 (1995) 5. vallous, n. a., gavrielidou, m. a., karapantsios, t. d. and kostoglou, m. performance of a double drum dryer for producing pregelatinized maize starches. journal of food engineering, 51, 171–183 (2002) 6. vasseur, j., abchir, f. and trystram, g. modelling of drum drying. in: mujumdar a. s. and filkova i. (eds), drying ’91. amsterdam: elsevier applied science publishers,pp. 121–129 (1991a) 7. vlachos, n. a. and karapantsios, t. d. water content measurement of thin sheet starch products using a conductance technique. journal of food engineering, 46(2),91– 98 (2000). 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 rotation speed, rpm 104 106 108 110 112 114 116 118 120 122 d ru m t e m p e ra tu re , c feed conc. 7g/100g feed conc. 10g/100g feed conc. 13g/100g 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 rotation speed, rpm 6 8 10 12 14 16 18 20 22 24 m oi st ur e, g /1 00 g w .b feed conc. 7g/100g feed conc. 10g/100g feed conc. 13g/100g 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 roation speed, rpm 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 m a ss f lo w r a te feed conc. 7g/100g feed conc. 7g/100g feed conc. 7g/100g ijcpe vol.5 no. 3 (2007) ijcpe vol.10 no. 3 (september 2009) iraqi journal of chemical and petroleum engineering vol.10 no.3 (september 2009) 18 issn: 1997-4884 prediction of effective bed thermal conductivity and heat transfer coefficient in fluidized beds majid i. abdul-wahab * and suha a. mohammed * chemical engineering department college of engineering university of baghdad – iraq abstract experimental study of heat transfer coefficients in air-liquid-solid fluidized beds were carried out by measuring the heat rate and the overall temperature differences across the heater at different operating conditions. the experiments were carried out in q.v.f. glass column of 0.22 m inside diameter and 2.25 m height with an axially mounted cylindrical heater of 0.0367 m diameter and 0.5 m height. the fluidizing media were water as a continuous phase and air as a dispersed phase. low density (ploymethyl-methacrylate, 3.17 mm size) and high density (glass beads, 2.31 mm size) particles were used as solid phase. the bed temperature profiles were measured axially and rad ially in the bed for different positions. thermocouples were connected to an interface system and these measurements were monitored by computer on line. theoretical analysis has been carried out to solve the differential equation governing heat transfer in the gas-liquid-solid fluidized system with its boundary conditions. finite difference technique was used as a suitable numerical method to find the solution. by applying the temperature profiles found experimentally in solved equation, effective thermal conductivity values were found. keywords: fluidized beds, gas-liquid-solid, heat transfer, effective thermal conductivity. introduction gas-liquid-solid fluidization is defined as an operation in which a bed of solid particles is suspended in gas and liquid medium due to the net drag force of the gas and liquid flowing opposite to the gravitational or buoyancy force on the particles. the liquid stream forms the continuous phase, while the gas stream forms the dispersed phase. such an operation generates considerable intimate contact among the gas, liquid and solid particles in the systems and provides substantial advantages for applications in physical, chemical or biochemical processing involving gas, liquid and solid phases (muroyama and fan, 1985). three-phase fluidized beds have been extensively adopted in many industrial processes. the high heat transfer rate is recognized as one of the main characteristics for the wide application of three-phase fluidization. the hydrodynamics, heat and mass transfer of the beds have been carried out using systems of high-density particles (1700-2600 kg/m3). these particles are employed in hydrotreating and hydrocracking of petroleum products. the development of the advanced biological fluidized reactors which use light catalyst particles of densities range from 1050 to 1300 kg/m3 directed some of these studies towards the low-density particles fluidized beds. the studies began to project highlight upon the fundamental characteristics (hydrodynamics, heat and mass transfer) in three-phase fluidized beds containing low–density particles (tang and fan, 1990, nore et al., 1992, nore et al., 1994, samir and fan, 1993, 1994, abdul wahab, 1997, van zeen, 2003). the hydrodynamics are widely investigated (shah et al., 1978 and muroyama and fan, 1985) by both experimental and mathematical studies. although the heat and mass transfer are also investigated, but there is a lack in information concerning these fields. university of baghdad college of engineering iraqi journal of chemical and petroleum engineering prediction of effective bed thermal conductivity and heat transfer coefficient in fluidized beds 2 ijcpe vol.10 no. 3 (september 2009) heat transfer studies in three-phase fluidized beds are classified into two groups. one deals with wall-to-bed heat transfer (kato et al., 1981, muroyama et al., 1986 and nore et al., 1994, zorana et al.2008), and the other with immersed heater-to-bed heat transfer (baker et al., 1978, khan et al., 1983 and mogiliotou et al., 1988,luo and fan 2000, muroyama et al.2001, grace et al.2008). although most of these studies have resulted in correlating equation for the experimental data, a few have analyzed the systems mathematically and proposed mechanism of the heat transfer. furthermore, the immersed surface-to-bed heat transfer studies have used flate plate heaters (khan et al., 1983 and luo and fan, 2000) and cylindrical shaped (baker et al., 1978, mogiliotou, 1988 and muroyama et al.2001). the present study focused on predicting the two important heat transfer parameters in the three phase fluidized beds, namely; the heat transfer coefficient and the effective thermal conductivity for the low and high density fluidized beds heated by a cylindrical immersed heater. the study aimed also to investigate the radial temperature profile at different axial positions experimentally. the effects of liquid and gas flow rates on the heat transfer parameters will be examined experimentally and the equations describing the heat transfer process will be solved numerically by a finite difference technique. experimental work the experimental work was performed using q.v.f. glass test column of 0.22 m inside diameter and 2.25 m height. the column has a hemispherical bottom and consists of three sections; namely the working section, accumulation section and the liquid outlet header. the overall combined height of these sections was 2.25 m. the schematic diagram of the experimental equipment is shown in fig. 1; more details can be found elsewhere (suha, 2009). the working section of the column (1.0 m height) was located between the distributor and the accumulation section. five taps were used for mounting thermocouples axially. the axially taps were cemented to the column body by using an adhesive material (which has high thermal resistance) to prevent leakage. three taps were used for mounting thermocouples in radial positions. the radial taps were located in vertical teflon pipe and they were fixed axially with different radii, the teflon pipe was moved in five axial positions. the accumulation section (0.7 m height) acted as a reservoir to accumulate large quantity of fluid. the top of the accumulation section protruded into a concentrically mounted outlet header (a perspex box of 0.25 m x 0.25 m x 0.75 m). the header thus, acted as a weir over which the liquid flowed, thereby maintaining an approximately constant head in the column. the liquid exited from the outlet header through three hoses which were provided with valves to enable varying proportions of the flow to be either returned to the feed reservoir or sent to the drain. the liquid phase employed in all experiments is tap water. it was pumped through the column by means of a centrifugal pump. the water flow rate was regulated by means of globe valve connected at the discharge of the pump and also in the main feed line and measured with calibrated rotameter. enough length of pipe was placed between the main feed globe valve and the rotameter to prevent any disturbance in the water flow passing through the rotameter. furthermore, a by-pass line with valve was located at the outlet of the pump to direct any excess flow of water back to the feed vessel (q.v.f.) spherical vessel of 0.1 m 3 capacity. solid particles were supported on a perforated plate (like mesh) of spaced holes of 1 mm diameter which served as a continuous phase distributor. the distributor was situated between the main column section and the entrance of the continuous phase which was introduced through a 2.54 cm pipe from liquid reservoir. polymer (polymethyl-mthacrylate) particles of 3.17 mm average diameter and 1170 kg/m 3 density, and glass beads of 2.31 mm average diameter and 1910 kg/m 3 density were selected as packing. the heater assembly shown in fig. 2, it was installed vertically at 0.3 m above the distributor as a heat source in the immersed heater-tobed system consisted of a copper cylinder of 0.0366 m outside diameter and 0.5 m height. two 0.013 m diameter by 0.3 m length, 3000 w/220 v electric heating u shaped elements were located in wells drilled inside the cylinder. the space between the heating elements and the cylinder was filled with sand to give a good heat distribution and to prevent the damage of heater. three copper-constantan thermocouples (type-j) were imbedded in the copper cylinder to measure the surface temperature of the heater. they were positioned at the 0.15 m, 0.25 m and 0.35 m from the bottom of the heater respectively. they were positioned at different angles along the heater surface, i.e. 120 o a part. the thermocouple junctions were inserted in holes drilled in the surface and welded. four copper rods of equal length and of cross shape were connected to the ends of the heater. this arrangement was adopted to ensure the heater at the center of the column. dr. majid i. abdul-wahab and suha a. mohammed 3 ijcpe vol.10 no. 3 (september 2009) fig. 1 schematic diagram of the equipment fig. 2 the heater results and discussion heat transfer coefficient the heat transfer coefficient (h) between the immersed heater and the bed can be influenced by the resultant flow behavior of dispersed bubbles, fluidizing particles and the continuous medium. thus, the effect of individual flow behavior on the heat transfer coefficient has been determined. the average heat transfer coefficient values calculated from the experimental measurement of temperature differences are plotted versus the velocity of gas for various values of liquid velocities. figures 3-8 show these plots for different values of heat flux from the heater. it is shown clearly that the heat transfer coefficient generally increases with both liquid velocity (ul) and gas velocity (ug). the corresponding values of heat transfer coefficients at the same values of liquid and gas velocities show an increasing trend with the increase of heat flux from the heater. this increase in h values can be attributed to the effect of heating level on the physical properties of both gas phase and liquid phase in the bed. figures present the experimental values of average heat transfer coefficients versus liquid velocity for various gas velocities for different heat fluxes from the heater. fig. 3 h vs. at different values of , q = 1060 w 1. heater element 2. water distributor 3. gas distributor 4. interphone 5. computer 6. water rota meter 7. centerfeugal pump 8. reservoir 9. accumulation section 10. gas rot meter compressor thermocouples heating element copper cylind er prediction of effective bed thermal conductivity and heat transfer coefficient in fluidized beds 4 ijcpe vol.10 no. 3 (september 2009) fig. 4 h vs. at different values of , q = 1975 w fig. 5 h vs. at different values of , q = 2250w fig. 6 h vs. at different values of , q = 918w fig.7 h vs. at different values of , q = 1975w fig. 8 h vs. at different values of , q = 2000 w the increase of (h) can be attributed to the turbulence generated with an injection of gas flow into the liquid fluidized beds (baker et al., 1978, chiu and ziegler, 1983). the effect of the generated turbulence on the heat transfer may be governed by its intensity and distribution in the bed. the initial increase of h with liquid velocity is due to the increase of turbulence, oscillatory motion of the fluidized solid particles, and fluid elements which are rapidly displaced inside the bed, generating micro-eddies of fluid. the heat transfer in the three-phase fluidized beds is mainly affected by the heat transfer coefficient near the heater surface region which is controlled by conduction through the liquid film covering the heater surface. liquid phase velocity has a significant effect on the heat transfer coefficient in the three-phase fluidized beds with an additional effect of the gas phase velocity. dr. majid i. abdul-wahab and suha a. mohammed 5 ijcpe vol.10 no. 3 (september 2009) the experimental results are fitted in the following empirical correlation using linear regression technique: for polymethyl-methacrylate particles, ρ = 1170 kg/m 3     25.036.053.0 re(pr)re54.1 gnu  (1) for glass beads particles, ρ = 1921 kg/m 3 (2) temperature profiles typical radial temperature profiles measured at various axial positions are shown in figs. 9 and 10 for low and high particles density at constant gas and liquid velocity, figs.11 and 12 at various gas velocities, and figs.13 and 14 at various liquid velocities. in these figures the effect of gas and liquid velocities and axial positions on the radial temperate profile are shown by plotting the dimensionless temperature (t-to)/(ts-to) versus the dimensionless radial distance r/r. the radial temperature profile is relatively high at a low gas velocity in which low degree of mixing is caused by uniform fine bubbles, where the flow mode is termed "dispersed bubble flow" (muroyama et al., 1978). on the other hand, the radial temperature profile decreases considerably at higher gas velocities at which slug flow mode dominates, where significant bed mixing occurs. effective radial thermal conductivity in fluidized beds, heat can be transferred in radial direction by several mechanisms. it can be transferred through the particles by conduction and through the fluid by conduction and convection. all these heat transfer mechanisms have been assumed to occur by conduction according to an effective radial thermal conductivity (ker ). this is equivalent to supposing that the bed is replaced solid of thermal conductivity equal to ker. therefore the effective thermal conductivity is a property of the bed; its value depends on large number of variables, such as flow rate, particle diameter, porosity, thermal conductivities of the fluids as well as solid phase and temperature level. however, dividing ker into separate contributions, each of them corresponds to mechanisms of heat transfer is not possible in the three-phase fluidized beds because of the complexity of the problem. many correlations have been developed on this basis for gas-solid fluidized beds and the gas-solid fixed bed. however, no reliable correlation was found in the literature to estimate the value of effective thermal conductivity in the gas-liquid-solid fluidized beds. therefore, the most logical method is to solve the differential equation that governing the heat transfer process numerically, and then by applying the experimental temperature profile in the solution, from which the effective radial thermal conductivity can be obtained. mathematical model the differential equation governing the heat transfer process in cylindrical coordinate for ga-liquid-solid fluidized beds can be written as 0 1 2 2                  r t r rr k z t k z t gc erezp (3) pggpllp cgcggc  (4) where gl and gg are the mass velocity of the liquid phase and gas phase respectively, kez and ker are the effective axial and radial thermal conductivities respectively. the boundary conditions of the problem are  ttgc z t kzcb opez     01.. (5a) 02..     z t lzcb (5b) * *3.. q r t kand q z t ksurfaceheateratcb er ez       (5c) 04..     r t rrcb (5d) equation 3 with its boundary conditions (eqs. 5a-5d) was solved numerically using matlab technique to find the theoretical axial and radial temperature distribution in the bed. the theoretical and experimental profiles were matched in order to find the values of effective radial thermal conductivity that satisfied the solution. figs. 15 and 16 show the variation of the effective radial thermal conductivity with the gas velocity for a given particle density at different liquid velocities on log-log scale. figs. 17 and 18 show the variation of the effective thermal conductivity with the liquid velocity at different gas velocities. the effective radial thermal conductivity is well correlated in terms of dimensionless groups. for glass beads: 27.035.0 rere5.1 gl l er k k  (6) for polymethyl-methacrylate particles: 07.08.0 rere4.2 gl l er k k  (7) prediction of effective bed thermal conductivity and heat transfer coefficient in fluidized beds 6 ijcpe vol.10 no. 3 (september 2009) fig. 9 radial temp. profile for pm particles fig. 10 radial temp. profile for glass beads fig. 11 radial temp. profile for pm particles fig. 12 radial temperature for glass beads fig. 13 radial temp. profile for pm particles fig. 14 radial temp. profile for glass beads dr. majid i. abdul-wahab and suha a. mohammed 7 ijcpe vol.10 no. 3 (september 2009) fig. 15 vs. at different values of fig.16 vs. at different values of fig. 17 vs. at different values of fig. 18 vs. at different values conclusions 1. the temperature profiles in the gas-liquid-solid fluidized beds are found to be significant, indicating the presence of considerable resistance in the core of the bed in series with the resistance at the heater surface. 2. the effective radial thermal conductivity increases with the increase in liquid velocity. in three-phase fluidized beds it depends on the bubble flow modes, in the coalesced bubble flow regime the effective radial thermal conductivity increases significantly with increasing gas velocity especially at low liquid velocities, while in the dispersed bubble flow regime it is little affected by the introduction of the gas phase. 3. the heat transfer coefficients and effective radial thermal conductivities are increasing functions of the density of the particles. references 1. abdul-wahab, m.i., (1997) “hydrodynamics and temperature distribution in low density particles fluidized beds using the finite element technique”, ph.d. thesis, university of baghdad. 2. baker, c.g.j., armstrong, e.r., and bergougnon, m.a. (1978), “heat transfer in three-phase fluidized beds”, powder technology, 21, 195-204. 3. chiu,t.m. and ziegler, e.n.,(1983), "heat transfer in three-phase fluidized beds" aiche, 29,677-685. prediction of effective bed thermal conductivity and heat transfer coefficient in fluidized beds 8 ijcpe vol.10 no. 3 (september 2009) 4. grace, j.r. and stefanova, a.,"heat transfer from immersed vertical tube in a fluidized bed of group a particles near the transition to the turbulent fluidization flow regime" international journal of heat and mass transfer, (2008). 5. kato, y., uchida, k., kago, t. and morooka, s., (1981), “liquid holdup and heat transfer coefficient between bed and wall in liquid-solid and gas-liquid-solid fluidized beds”, powder technology, 28, 173-179. 6. khan a.r. and richardson, j.f., "heat transfer from plane surface to liquids and to liquid-solid fluidized beds",1983. 7. magiliotou, m., chem, y.m. and fan, l.s., (1988), “bed-immersed object heat transfer in a threephase fluidized bed”, aiche. j., 37, 1101-1106. 8. muroyama, k. and fan, l.s., (1985), “fundamentals of gas-liquid-solid fluidization”, aiche j., 31, no.1, 1-34. 9. muroyama, k., fukuma, m. and yasunishi, a., (1986), “wall-to bed heat transfer in liquid-solid and gas-liquid-solid fluidized beds”, part ii: gasliquid-solid fluidized beds, can. j. chem. eng., 64, 409-418. 10. muroyama k, okumichi s, goto y, yamamoto y, saito s, (2001), "heat transfer from immersed vertical cylinders in gas-liquid and gas-liquidsolid fluidized beds", chemical engineering and technology, vol. 24, issue 8. 11. nore, o., briens, c., margaritis, a. and wild, g. (1992), “hydrodynamics gas-liquid mass transfer and particle-fluidized bed for biochemical process applications”, chem. eng sci., 47, 3573-3580. 12. nore, o., briens, c., margaritis, a. and wild, g. (1994), “wall-to-bed heat transfer in three-phase fluidized beds of low density particles",can. j.chem.eng.,72,546-550. 13. samir kumar, k. kusakabe and l. -s. fan (1993), "heat transfer in three-phase fluidized beds containing low-density particles", chemical engineering science, vol. 48, issue 13. 14. shah, y.t., stiegel, g.j, and sharma, m.m.,"backmixing in gas-liquid reactors", aiche j., 1978. 15. suha, a. mohammed, “ prediction of effective bed thermal conductivity and heat transfer coefficient in fluidized beds”, m.sc. dissertation, baghdad university (2009). 16. tang, w.t. and fan, l.s., "hydrodynamics of a three-phase fluidised bed containing low-density particles" aiche, 1989. 17. van zeen, (2003), “hydrodynamics of a liquid-liquidsolid fluidized bed bioreactor”,ph.d. thesis wageningen university, the netherlands 18. zorana, a., and radmila, g., "wall-to-bed heat transfer in vertical hydraulic transport and in particulate fluidized beds" international journal of heat and mass transfer, volume 51, issues 25-26, december 2008, pages 5942-5948. iraqi journal of chemical and petroleum engineering vol.18 no.2 (june 2017) 1 11 issn: 1997-4884 the effect of crystallization time and acid type on the synthesis of nano-gamma alumina using double hydrothermal method abdul-halim a.k. mohammed 1 , hussein q. hussein 2 and mohammed sabah mohammed 3 1. gas and petroleum engineering department, college of al-faraby university 2. chemical engineering department, college of engineering, university of baghdad 3. office of assit. dean for scientific and student affairs, college of engineering, alnahrain university abstract double hydrothermal method was used to prepare nano gamma alumina using aluminum nitrate nano hydrate and sodium aluminate as an aluminum source, ctab (cetyltrimethylammonium bromide) as surfactant, and variable acids: weak acids like; citric, and acitic acids, and strong acids like; hydrochloric and nitric acids as a bridge between aluminum salts and surfactant. different crystallization times 12, 24, 48, and 72 hrs were applied. all the batches were prepared at ph equals to 9. xrd diffraction technique was used to investigate the crystalline nano gamma alumina pure from surfactant. n2 adsorption-desorption (bet) was used to measure the surface area and pore volume of the prepared nano alumina, the average particle size and the morphology of the surface of nano gamma alumina were estimated using afm and sem techniques, respectively. the sharpness of the peaks increased with increasing of crystallization time. the surface area, pore volume, and average particle size were decreased with increasing crystallization time. the best result of surface area was 383 m 2 /gm obtained using citric acid at 12 hr crystallization time, while the best results of pore volume and average particle size were 0.54cm 3 /gm and 72.37nm obtained using hydrochloric acid at12 hr crystallization time. low agglomeration with hexagonal structure obtained using weak acids, while agglomeration occurred and clusters formed using strong acids. key words: gamma alumina, nanoparticle, double hydrothermal, ctab, crystallization time and acid type. introduction the nano structured alumina material is a porous crystalline system having a nano particle size range 1-100 nm used in form of particles. aluminum oxide exists in various structures; only two phases are of interest, namely the nonporous crystallographically ordered alpha-al2o3 which was composed to spherical shape, and the porous amorphous gamma-al2o3 which was composed to spherical or non-spherical or irregular hexagonal shape. gammaal2o3 is used as a catalyst by itself, and university of baghdad college of engineering iraqi journal of chemical and petroleum engineering the effect of crystallization time and acid type on the synthesis of nano-gamma alumina using double hydrothermal method 2 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net also used as adsorbent because of its porous structure [1, 2]. gamma alumina is used as a support alone, or as a support of active metals in catalysis reactions due to its high thermal stability and the ability to be shaped into mechanically stable extrudes and pellets, also alumina is a poly anion of positive charge at ph values below 7 and negative at higher values, offering many possibilities to bind many ionic catalyst precursors [3]. supported nano alumina with high surface area and pore volume is used extensively as catalyst, catalytic supports, and adsorbent for chemical processes. the surface of the nano particles plays an important role in their catalytic properties [4, 5 and 6]. the starting materials of synthesis nano gamma alumina are either expensiveand sensitive to moisture content like aluminium alkoxides or cheap and available materials like aluminium salts, clays, and pure aluminium powder [6]. different materials like; surfactant, dispercents and tamplets were used in the synthesis of nano gamma alumina with high texture properties using different methods like; sol gel, hydrothermal treatment, precipitation, lazer oblation, solution composition, spray pyrolysis…etc [7, 8, 9 and 10] . aguado et al. 2005 [11] used sol-gel techniques to prepare nano gamma alumina using two types of surfactant and aluminum alkoxides source of aluminum, and hydrochloric acid. uniform structure of produced catalyst was achieved with increasing acid/al source (wt/wt) ratio, while decreasing the amounts of surfactant used causes decreasing in pore size of the prepared catalyst. yi jian hong 2009 [12] used precipitation technique to prepare nano gamma alumina using sodium aluminate and oxalic acid as a precipitation agent. the effect of the ph of sodium aluminate and oxalic mixtures and the ph of washing at ph range 7-9 on the purity of the catalyst was studied, and found that pure crystalline gamma alumina was obtained using ph <8, while beta alumina was obtained at ph >8. ming bao et.al.2010 [13] prepared nano gamma alumina in the presence of two sources of alumina, cetyltrimethylammonium bromide (ctab) as surfactant, citria acid, and different molar ratios of sodium citrate by double hydrothermal treatment using auto clave with temperature 170 0 c for 24 hrs,the optimum results acting in 0.2 molar ratio of sodium citrate with respect to aluminium salts with surface area 398 m 2 /gm, and pore volume 0.59 m 2 /gm [12]. dahlan et.al. 2012 [14] prepared nano alumina adding urea as a fuel with molar ratio 29:153:1:2028 of aluminium salt,ctab,urea,and water using hydrothermal method producing 203 m 2 /gm, 0.14 cm 3 /gm of nano gamma alumina. faramawy et.al. 2014 [15] synthesis of nano gamma alumina by hydrothermal technique using microwave irradiation for the crystallization of aluminium salt and ctab surfactant and found that the increasing in the time and power of the reaction leads to increase the crystinallity and the texture properties of the prepared catalyst .hawraa 2016 [16] prepared nano gamma alumina with 56 nm, 256 m 2 /gm surface area, and 0.374 cm 3 /gm pore volume by sol gel method using aluminum chloride dissolved in ethanol and ammonia. the aim of this work is to prepare nano alumina by using double hydrothermal treatment method, and to study the effect of crystallization time and acid type on the characterstics of prepared catalyst like; xrd, afm, surface area, pore volume and sem. http://www.iasj.net/ abdul-halim a.k. mohammed, hussein q. hussein and mohammed sabah mohammed -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 3 experimental work materials aluminum nitrate nona hydrate (al(no3)3.9h20, 100% purity, himedia company), and sodium aluminate (naalo2, 100 % purity, himedia company) were used as sources of aluminium. cetyltrimethylammonium bromide (ctab, 99% purity, wuhan kemi-works, chemical co.ltd) was used as a surfactant, different acids like; cirtic acid (ca, 100% purity), acetic acid (aa, 100% purity), hydrochloric acid (hcl, 99% purity), and nitric acid( hno3, 99% purity) acting from riedel-de haen were used as a structure direct agent, and finally sodium hydroxide (naoh, 99% purity, sigma) was used to adjust the ph of the mixtures. preparation of nano the nano gamma alumina was prepared depending on the previous work of ming bao et. al. 2010 [13] by dissolving aluminium nitrate nonahydrate, citric acid and ctab surfactant in suitable amount of dionized water, then sodium aluminate was dissolved in suitable amount of dionized water and added drop by drop to the first mixture under vigorous stirring 1000 rpm. the molar composition of the mixture al/ctab/citric acid/h2o is 1.0/0.1/0.2/125, a white gel formed immediately, after further stirring for 3 hrs, the mixtures adjusted at ph equal to 9. the produced gel was then placed in a teflon-lined stainless steel auto clave to start the crystallization at 180 0 c crystallization temperatures for crystallization time of 12, 24, 48, and 72 hrs. the crystallization product was filtered using nano filter papers (slow), and washed by deionized water and ethanol for several times to eliminate the contaminants. the product was dried at temperature 100 0 c for 24 hrs, and then calcined at 600 0 c. the procedure above was repeated using acetic acid, hydrochloric acid, and nitric acid instead of citric acid. characterization of nano x-ray diffraction analysis was used to characteristic the phase of the prepared samples using x-ray diffract meter type shimadzu srd 6000, japan, with cu wave length radiation (1.54060) in the 2 theta range from 10-80 0 , and fixed power source (40 kv, 30 ma) by the ministry of science and technology. the surface area, and pore volume of the samples were conducted at the petroleum research and development center in baghdad using brunauer emmett and teller (bet) method with thermo analyzer/usa device. the average particle size and the morphology of surface of each sample were calculated at the department of chemistry / college of science /university of baghdad using atomic force microscope device (type angstrom, scanning probe microscope, advanced inc, aa 3000, usa). the morphology of the structure of nano gamma alumina was studied using fei nova nano sem device located at chemical engineering department / tehran university. the specimen of prepared nano gamma alumina was dispersed in ethanol and coated by gold using special cell. results and discussions x-ray diffraction (xrd) from the figures 1 to 7 it is clear that all the coordinates of the peaks of prepared samples were accepted the three strong standard peaks of gamma alumina (311-65b intensity-2.39 d spacing), (400-80b intensity-1.98 d spacing), and (410-100 b intensity-1.4 d spacing) which represents the pure substantial crystallization of http://www.iasj.net/ the effect of crystallization time and acid type on the synthesis of nano-gamma alumina using double hydrothermal method 4 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net international alumina card (jcpds) files no. (29.0063). all the xrddiffraction figures from 1 to 7 represented high crystalline gamma alumina at ph equal to 9. the broading of the peaks may be occurred due to the role of the ctab surfactant used in the process which was released after calcination producing nano particle size [17, 11]. the increasing in crystallization time from 12 to 72 hrs causes little increasing in crystinallity and increasing in the sharpness of the peaks shown in figures 1 to 4 as observed by marzieh jalilpour, 2012 [18]. the effect of varying the acid type on the xrd diffraction is shown in the figures 1, 5, 6 and 7. the broading in the peaks occurred from using hydrochloric and nitric acids are larger than that occurred from using weak acids like; citric and acetic acids with the same degree of crystinallity because these experiments were attempted at the same conditions. fig. 1: xrd diffraction of the nano gamma alumina prepared using citric acid at 180 0 c crystallization temperature, 12 hrs crystallization time and calcination temperature 600 0 c fig. 2: xrd diffraction of the nano gamma alumina prepared using citric acid at 180 0 c crystallization temperature, 24 hrs crystallization time and calcination temperature 600 0 c http://www.iasj.net/ abdul-halim a.k. mohammed, hussein q. hussein and mohammed sabah mohammed -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 5 fig. 3: xrd diffraction of the nano gamma alumina prepared using citric acid at 180 0 c crystallization temperature, 48 hrs crystallization time and calcination temperature 600 0 c fig. 4: xrd diffraction of the nano gamma alumina prepared using citric acid at 180 0 c crystallization temperature, 72 hrs crystallization time and calcination temperature 600 0 c fig. 5: xrd diffraction of the nano gamma alumina prepared using acetic acid at 180 0 c crystallization temperature, 12 hrs crystallization time and calcination temperature 600 0 c http://www.iasj.net/ the effect of crystallization time and acid type on the synthesis of nano-gamma alumina using double hydrothermal method 6 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net fig. 6: xrd diffraction of the nano gamma alumina prepared using hydrochloric acid at 180 0 c crystallization temperature, 12 hrs crystallization time and calcination temperature 600 0 c fig. 7: xrd diffraction of the nano gamma alumina prepared using nitric acid at 180 0 c crystallization temperature, 12 hrs crystallization time and calcination temperature 600 0 c surface area and pore volume the surface area and pore volume of the nano catalyst play a very important role for the activity of the nano catalyst, because high surface area leads to high active sites causes increasing in activity. table 1 shows the results of surface area and pore volume of the samples for different conditions. keeping the mixtures at 180 0 c crystallization temperature during 24 hrs may allow the particles to become close to each other causes decreasing in surface area besides the reduction in pore volume. the increasing in crystallization time from 48 to72 hrs did not effect on the results of surface area and pore volume because the stable structure of boehmite occurred causes no change in these values as mentioned by yvan j.et al. 2012. the addition of acids beside the surfactant to the starting materials had very important role, because it represents the bridge between the surfactant and the source of aluminum ions, besides its role as a dispersant agent as mentioned by ki wom jun et al. 2009. the dispersant degree varies from acid to another one in the order of hydrochloric acid <nitric acid <acetic http://www.iasj.net/ abdul-halim a.k. mohammed, hussein q. hussein and mohammed sabah mohammed -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 7 acid < citric acid prevent the agglomeration of the particles causes low surface area with high pore volume. table 1: the values of surface area and pore volume at different conditions synthesis conditions acid type surface area,m 2 /gm pore volume,cm 3 /gm 180 0 c,12hrs,and 600 0 c citric acid 383.0 0.430 180 0 c,24hrs,and 600 0 c 338.8 0.430 180 0 c,48hrs,and 600 0 c 339.0 0.430 180 0 c,72hrs,and 600 0 c 338.8 0.365 180 0 c,12hrs,and 600 0 c acetic acid 203.0 0.500 180 0 c,12hrs,and 600 0 c hydrochloric acid 183.4 0.540 180 0 c,12hrs,and 600 0 c nitric acid 183.1 0.500 particle size the atomic force microscopy (afm) method was used to find the average particle size, particle size distribution, and the results of the particle size are listed in table 2. the average particle size of the prepared nano alumina was in the nano scale catalyst for all crystallization temperatures. increasing the crystallization time at 180 0 c causes drop in surface area and pore volume of the prepared samples, and the particles became bigger due to agglomeration reaching to the levels out of the nano scale level at crystallization time higher than 24 hrs as observed by y van.et al.2012 [19]. using variable acids in the presence of the surfactant produced different ranges of average nano gamma alumina. hydrochloric and nitric acids produced nano gamma alumina with average particle size less than 75 nm,while weak acids like; aceti and citric acids produced nano gamma alumina with average particle size above 95 nm.these results are near the results obtained by hawraa 2016 [16]. table 2: the values of particle size distribution and average particle size at different conditions synthesis conditions acid type particle size distribution,nm average particle size,nm 180 0 c,12hrs,and 600 0 c citric acid 75-160 92.72 180 0 c,24hrs,and 600 0 c 50-140 103.17 180 0 c,48hrs,and 600 0 c 40-160 106.59 180 0 c,72hrs,and 600 0 c 70-150 110.37 180 0 c,12hrs,and 600 0 c acetic acid 70-130 96.44 180 0 c,12hrs,and 600 0 c hydrochloric acid 35-100 72.37 180 0 c,12hrs,and 600 0 c nitric acid 55-130 74.82 scanning electron microscopy (sem) the morphology of the surface of prepared nano gamma alumina samples is obtained at magnification of 60 kx and zoom of 500 nm. increasing crystallization time shown in figures 8 to 11. using crystallization time above 12 hrs causes agglomeration in particles, and reduces nano particles lead to drop in surface area and pore volume as observed by y van. et al. 2012 [19]. uniform hexagonal shape of particles with low agglomeration is observed by using weak acids like; citric and acetic acids shown in figures 8 and 12. agglomeration and formation of clusters is observed by using strong hydrochloric and nitric acids shown in figures 13 and 14 leads to low surface area with high pore volume. this morphology is the same with the morphology acting by hawraa 2016 [16]. http://www.iasj.net/ the effect of crystallization time and acid type on the synthesis of nano-gamma alumina using double hydrothermal method 8 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net fig. 8: sem image of the nano gamma alumina prepared using citric acid at 180 0 c crystallization temperature, 12 hrs crystallization time and calcination temperature 600 0 c fig. 9: sem image of the nano gamma alumina prepared using citric acid at 180 0 c crystallization temperature, 24 hrs crystallization time and calcination temperature 600 0 c fig. 10: sem image of the nano gamma alumina prepared using citric acid at 180 0 c crystallization temperature, 48 hrs crystallization time and calcination temperature 600 0 c http://www.iasj.net/ abdul-halim a.k. mohammed, hussein q. hussein and mohammed sabah mohammed -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 9 fig. 11: sem image of the nano gamma alumina prepared using citric acid at 180 0 c crystallization temperature,72 hrs crystallization time and calcination temperature 600 0 c fig. 12: sem image of the nano gamma alumina prepared using acetic acid at 180 0 c crystallization temperature, 12 hrs crystallization time and calcination temperature 600 0 c fig. 13: sem image of the nano gamma alumina prepared using hydrochloric acid at 180 0 c crystallization temperature, 12 hrs crystallization time and calcination temperature 600 0 c http://www.iasj.net/ the effect of crystallization time and acid type on the synthesis of nano-gamma alumina using double hydrothermal method 10 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net fig. 14: sem image of the nano gamma alumina prepared using nitric acid at 180 0 c crystallization temperature, 12 hrs crystallization time and calcination temperature 600 0 c conclusions nano gamma alumina was successfully synthesized using double hydrothermal method in the presence of ctab surfactant using different crystallization times, and different structure direct agent. xrd diffractions represent the crystalline nano gamma alumina pure from surfactant. the sharpness of the peaks increased with increasing of crystallization time. using strong acids causes broading in peaks larger than that occurred in peaks using weak acids. the surface area, pore volume, and average particle size were decreased with increasing crystallization time. the best result of surface area obtained using citric acid at 12 hr crystallization time, while the best results of pore volume and average particle size obtained using hydrochloric acid at 12 hr crystallization time. low agglomeration with hexagonal structure obtained using weak acids, while agglomeration occurred and clusters formed using strong acids. references 1. speight b , j.g., 2002, "chemical and process design handbook", the mcgraw-hill companies. 2. suzuki,, m., 1990, "adsorption engineering handbook" ,kodansha ltd, tokyo and elsevier science b.v., amsterdam. 3. zaki, t., mohmed, n.h., nessim, m.i., and salam, h. a.,2013, "characterization znd application of nano-alumina sorbents for desulfurization and dearomatization of suez crude petroleum", fuel processing technology, 106:625630. 4. marino f., descorme c., and duprez d., 2005, "supported base metal catalysts for the preferential oxidation of carbon monoxide in the presence of excess hydrogen", j. of appl.cat. vol.58, pp. 175-183. 5. carmo m., paganin v.a., roselen j.m., 2005, "alternative supports for the preparation of catalysts for low temperature fuel cells: the use of carbon nanotubes", j. of power sources, vol.142, pp. 169-176. 6. parida, k.m., and amaresh c., 2009, "synthesis and characterization of nano-sized porous gamma –alumina by http://www.iasj.net/ abdul-halim a.k. mohammed, hussein q. hussein and mohammed sabah mohammed -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 11 control precipitation method", institute of minerals and materials technologies, india, vol (113), 244248. 7. chengchao liu, jinlin li, kongyong liew, and junjiang zhu, 2012, "an enviromental friendly method for the synthesis of nanoalumina with controllable morphologies", j. of rcs advances, vol.2, pp.8352-8358. 8. veeradate piriyawong, voranuch thongpool, and piyapong asanithi, 2012, "praparation and characterization of alumina nanoparticles in deionized water using lazer ablation technique", j. of nanomaterials, article id 819403, 6 pages. 9. bustan afruz a., and tafreshi m.j., 2014, "synthesis of gamma alumina nanoparticle by different combustion modes using ammonium carbonate", indian j. of pure and applied physics, vol.52, pp. 378-385. 10. yousif jawad, 2009, "synthesis and characterization of zeolite nanoparticles catalysis used for nhexane conversion.", phd thesis, university of baghdad, college of engineering, chemical engineering department. 11. aguado j., escola j. m., and castro m.c., 2005, "sol-gel synthesis of nanostructured gamma alumina templated by cationic surfactant",j. of micro. and meso. mater., vol.82, pp.181-192. 12. yi jian hong, sun you yi, and gao jian feng, 2009 "synthesis of crystalline γ alumina with high purity", trans. nonferrous met. soc. china, vol.19 pp.1237-1242. 13. ming bo yue, wen qian jiao, yi meng wang, and ming yuan he, 2010, "ctab-directed synthesis of mesopores gamma alumina promoted by hydroxyl polyacids", j.of micro., and meso. mat., vol.132, pp.226-231. 14. dahlan, i nyoman marsih, and joonjai panpranot, 2012, "gamma alumina nanotubes prepared by hydrothermalmethod as support of iron,cobalt,and nickel for fischertropsch catalysts", j. of chemistry and materials research, vol.2, no.3, pp.31-38. 15. faramawy s., el-shall m. s., and abd el wahed m.g., 2014 "synthesis of high surface area gamma alumina by microwave irradiation process", j. of american science, vol.10, pp.9. 16. hawraa h., 2016, " preparation of nano ni-mo/ϒ-al2o3 catalyst for hydrodesulphurization of iraqi gas oil", msc.thesis, chemical engineering department, college of engineering, university of baghdad. 17. kianinia y., darban a.k., and rahnama b., 2014, "synthesis of nano sized mesoporous gamma alumina powder from domestic hamedan kaolin", iranian j. of materials and eng., vol.12, no.1, pp.59-65. 18. marzieh jalilpour, and mohammad fathalilou, 2012, "effect of aging time and calcination temperature on the cerium oxide nanoparticles synthesis via reverse coprecipitation method", int. j. of physics and science, vol.7, no.6, pp.944-948. 19. y van j.o., maria r., 2012 "synthesis of high surface area γ alumina from aluminium scrap and its use for the adsorption of metals:pb(ii),cd(ii), and zn(ii)", j. of applied science, vol.258, pp.10002-10011. 20. ki won jun, yun jo lee, scung moon kim, 2009, "method of preparing boehmite and gamma alumina with high surface area", us patent, no.0104108 a1. http://www.iasj.net/ iraqi journal of chemical and petroleum engineering vol.15 no.2 (june 2014) 7584 issn: 1997-4884 kinetic of alkaloids extraction from plant by batch pertraction in rotating discs contactor khalid m. abed chemical engineering department, college of engineering-university of baghdad-iraq email: khalid.chemical82@gmail.com abstract a liquid membrane process of alkaloids extraction from datura innoxia solution was studied applying pertraction process in rotating discs contactor (rdc). decane as a liquid membrane and dilute sulphuric acid as stripping solution were used. the effect of the fundamental parameters influencing the transport process, e.g. type of solvent used, effect of disks speed, amount of liquid membrane and effect of ph for feed and strip solution. the transport of alkaloids was analysed on the basis of kinetic laws of two consecutive irreversible first order reactions. thus, the kinetic parameters (k1, k1, , tmax, and ) for the transport of alkaloids were determined. the effect of organic membrane type on percentage of alkaloids transport was found to be in the order (n-decane> n-heptane> n-hexane> ethyl ether). the results showed that the highest alkaloids extraction was obtained when using two stages, (10 rpm) discs speed, (ph=9.5) of feed solution and (ph=2) of acceptor solution in n-decane. observation showed that the membrane entrance rate constant k1 and percentage of alkaloids transported in strip phase increased with increasing numbers of stages but the exit rate constant k2 decreased. the alkaloids extraction ratio increased with increasing the disks speed from 5 to 10 rpm but decreased at 15 rpm and decreased when increasing the volume of membrane. also ph of feed and strip solution affected the extraction ratio and rate constants. keywords: extraction, batch pertraction, liquid membrane, alkaloids, kinetic, rotating disc contactor. introduction plants have been used as medicine for a long time. many of the natural products in plants of medicinal value offer new sources of drugs which have been used effectively in traditional medicine [1]. for medicinal interest, atropine alkaloid (chemical structure is shown in fig. 1) is found in plants of the solanaceae family, such as atropa, datura, duboisia and hyoscyamus. atropine is the chief alkaloid in atropa belladonna. it can be extracted from the plant as free bases using basic aqueous solution or as salts using acidified solution [2]. the liquid membrane technology has been effectively used to treat aqueous streams contaminated with metal ions [3]. the liquid membrane extraction was introduced as an alternative separation technique to the liquid-liquid iraqi journal of chemical and petroleum engineering university of baghdad college of engineering mailto:khalid.chemical82@gmail.com kinetic of alkaloids extraction from plant by batch pertraction in rotating discs contactor 76 ijcpe vol.15 no.2 (june 2014) -available online at: www.iasj.net extraction and to separation by means of solid polymeric membrane [4]. fig. 1: chemical structure of atropine alkaloid this property of membranes makes them useful in the textile and food industries, in hydrometallurgy, medicine, biotechnology, environmental protection, in the separation of hydrocarbons and gases, and in the concentration and separation of amino acids, metal ions and other mixtures and suspensions [5] [6]. this method provides low cost, simplicity, high efficiency and energy saving in comparison to other process. in the recent years, a remarkable increase of the application of liquid membranes has included bulk liquid membrane (blm), emulsion liquid membrane and supported liquid membrane [7]. a kinetic study of alkaloids transport through a liquid membrane was studied. the influence of ph in the aqueous feed solution and ph of stripping solution were also studied and the effect of stirring speed of disks, type and amount of liquid membrane on the transport of atropine through a blm were studied. the consecutive irreversible firstorder apparent rate constants, k1 and k2, have been determined. in the present work, transport of alkaloids n-decane bulk liquid membrane was studied. different experimental conditions, such as the effect of ph in feed and stripping solution, the rate of stirring speed and effect of time were also investigated. experimental work 1. chemicals and reagents studies of alkaloids permeation through the liquid membrane were carried out using atropine aqueous solutions. the atropine was extracted from datura innoxia seeds (collected in 2011, from the region of the college of agricultureuniversity of baghdad iraq) applying solid–liquid extraction. various reagents were used in this work as liquid membrane, n-decane (99% bdh), n-hexane (95% aldrich), n-heptane (99.5 hopkin and williams) and ethyl ether (99% fluka ag). ammonia (25% chemsupply) and sulfuric acid (98% gcc) were used to adjust the acidity of the aqueous solutions. 2. instruments the concentration of atropine alkaloids in the strip solution was measured by uv-spectrophotometer sp-3000 (optima inc) at wave length λ=257 nm. the ph values of the aqueous solutions were measured by means of the laboratory ph meter (crison, mm40). 3. three phase experiment 3.5 grams of datura innoxia seeds were milled to fine powder and leached by 250 ml of buffer solution of (nh3-(nh4)2so4) adjusted to appropriate ph. this solution was shaken for half an hour and filtered to obtain the feed solution. the stripping solution was adjusted to appropriate ph using few drops of sulfuric acid. using this type of acid and at the membrane/receiver interface, conditions were appropriate for atropine stripping and its accumulation in the receiver phase as atropine sulphate, which is insoluble in the organic liquid membrane. n-decane, n-hexane, n-heptane and ethyl ether were used as organic liquid membrane. khalid m. abed -available online at: www.iasj.net ijcpe vol.15 no.2 (june 2014) 77 4. bulk liquid membrane among the large variety of liquid membrane technique, the pertraction in rotating discs contactor (rdc) model was selected due to its stability [8, 9]. kinetic of atropine alkaloids in three phases system was studied in laboratory rdc, presented schematically in fig. 2. the lower part of the contactor is divided into four compartments: two for the feed and two for the stripping solution. the liquid membrane covers both aqueous solution and occupies the common upper part of the contactor. four hydrophilic membrane disks (1mm thickness and 18 cm in diameter) were fixed on a horizontal shaft and their lower parts immersed to compartments, with disks, in which aqueous phases (feed or strip) were immersed and due to rotation, were contacted with the lm phase. two peristaltic pumps were used to circulate both aqueous solutions to homogenize the aqueous solutions and to eliminate the dead zone or minimize it. for constant shaft rotating in small rpms, dc-motor (50 rpm) and variable dc power supply were used. the hydrophilic disks for each stage were made from stainless steel because of its resistance against the acids and bases with the added advantages of being very hygienic and easy to clean. fig. 2: scheme of a rotating film contactor: (1) body, (2) stage wall, (3) feed/stripping solution separating walls, (4) rotating discs, and (5) common shaft 5. kinetic procedure variation of atropine alkaloids concentration with time was directly determined on both feed (g/cm 3 ) and strip (g/cm 3 ) phases using uvspectrophotometer sp-3000 at wave length λ=257 nm. the corresponding change of atropine concentration in the membrane phase was determined from the material balance between the phases. for practical reason, dimensionless reduced atropine alkaloids concentration in the feed (rf), membrane (rm) and strip (rs) phases were used [10, 11]. , , …(1) where is the initial concentration of atropine alkaloids in the feed (donor) phase while cf, cm, and cs, are the atropine concentration in feed (donor), membrane and strip (acceptor) phases, respectively. from this expression, the material balance can be established as rf + rm + rs= 1. when rf, rm and rs values are inspected, the results suggest that atropine alkaloids transport obeys the kinetics of two consecutive irreversible first order reactions according to the kinetic scheme [11]. cf k1 cm k2 cs …(2) where k1 and k2 are the pseudo-first apparent rate constants for the membrane entrance and exit, respectively. the kinetic scheme for consecutive reaction systems can be described by considering the reduced concentrations as follows [11, 12]: …(3) …(4) …(5) kinetic of alkaloids extraction from plant by batch pertraction in rotating discs contactor 78 ijcpe vol.15 no.2 (june 2014) -available online at: www.iasj.net where j is the flux when k1 ≠ k2 and the integration of the above differential equation gives: …(6) …(7) …(8) where t is the time elapsed. substituting eqs. 6 – 8 into eqs. 3 – 5, ji can be expressed as: …(9) …(10) …(11) when (eq. 10) is equal to zero, the maximum fluxes of metal transport across blm are achieved as follows [13]: …(12) …(13) …(14) where and are the maximum fluxes of atropine transport in feed and stripping phases, respectively, while is the time at which the maximum fluxes are accomplished. from eq. 13, is derived as [13]: …(15) substituting eq. 15 into eq. 7, the value of at , i.e. , is obtained as follows [13]. …(16) since is equal to zero (eq. 13), the system is in steady state and, hence, (eq. 12) and (eq. 14) are equal to each other but of opposite signs, i.e. …(17) results and discussion 1. effect of type of solvent (liquid membrane) the transport study of atropine alkaloid was carried out in different solvents; n-decane, n-heptane, nhexane and ethyl ether, at ph of feed (phf =9.5), ph of strip (phs= 2), stirring discs speed= 10 rpm and volume of membrane =500 ml. the transport efficiency of atropine alkaloid was found to be good when using n-decane. but the transport efficiency was found to be less with nheptane, n-hexane and ethyl ether as shown in fig. 3 and table 1. about 75.41% of atropine was transported to the striping solution. table 1: the kinetic parameters for the extraction of atropine at different solvents type of solvent k1 (min -1 ) k2 (min -1 ) (min) (--) (min -1 ) (min -1 ) %atropine in s phase n-decane 0.00817 0.087 30 0.073 -0.00639 0.00639 75.41 n-heptane 0.00422 0.065 45 0.052 -0.00349 0.00349 71.06 n-hexane 0.00304 0.074 45 0.036 -0.00266 0.00266 24.61 eth. eth. 0.01742 0.005 30 0.043 -0.01033 0.01033 20.47 khalid m. abed -available online at: www.iasj.net ijcpe vol.15 no.2 (june 2014) 79 fig. 3: effect type of solvent on atropine; a. n-decane b .n-heptane c. n-hexane d. ethyl ether (experimental conditions: phf=9.5, phs=2, 10 rpm and one stage at 27 ) 2. effect of agitation speed it is well known that hydrodynamic conditions play an important effect in mass transfer from one phase to another phase at the interface between two liquid phases. in order to examine the effect of hydrodynamics on the atropine extraction, experiments were carried out with different agitation speeds, 5, 10 and 15 rpm at ph of feed (phf =9.5), ph of strip (phs = 2), stirring discs speed= 10 rpm and volume of membrane =500 ml. the percentage of atropine extracted is plotted versus time at different agitation speeds in fig. 4. higher rotation speed was not applied because of the increased risk of droplet formation and process deterioration [14]. the rate constant k1 and k2 were determined from equations 15 and 16 and are shown in table 2. table 2: the kinetic parameters for the extraction of atropine at different agitation speed agitation speed(rpm) k1 (min -1 ) k2 (min -1 ) (min) (--) (min -1 ) (min -1 ) %atropine in s phase 15 rpm 0.00367 0.0688 45 0.045 -0.00311 0.00311 17.62 10 rpm 0.00817 0.0870 30 0.073 -0.00639 0.00639 75.41 05 rpm 0.00336 0.0475 60 0.057 -0.00275 0.00275 22.64 0 20 40 60 80 100 0 20 40 60 80 100 120 % a tr o p in e time(min) (a) ra rm rf 0 20 40 60 80 100 0 20 40 60 80 100 120 % a tr o p in e time(min) (b) ca cm cf 0 20 40 60 80 100 0 20 40 60 80 100 120 % a tr o p in e time(min) (c) ra rm rf 0 20 40 60 80 100 0 20 40 60 80 100 120 % a tr o p in e time(min) (d) ra rm rf kinetic of alkaloids extraction from plant by batch pertraction in rotating discs contactor 80 ijcpe vol.15 no.2 (june 2014) -available online at: www.iasj.net fig. 4: effect of agitation speed; a. %atropine in stripping phase b. %atropine in feed phase (experimental conditions: phf=9.5, phs=2, one stage and 500ml of n-decane as liquid membrane) 3. effect of ph of feed solution the ph of feed solution plays an important effect on the extraction of atropine. in order to study the effect of ph in the feed phase (phf) on the mass transfer performance of pertraction process, ph in the feed phase is adjusted with ammonia buffer solution. experimental studies were carried out at various ph values from 7 to 12. preliminary tests were carried out to find the optimum phf solution. the results of the atropine extraction experiments are shown in fig.5. it is to be concluded that the best ph for the feed solution that gave good extraction is around 9.5. fig. 5: effect of ph of feed solution and the best ph for extraction of atropine (experimental conditions: phs=2, 10 rpm, one stage and 500ml of n-decane as liquid membrane) 4. effect of ph of striping solution the effect of ph of striping solution (phs) was studied for the range 1.5 – 3 and the results of atropine transport is shown in fig. 6. the percentage of atropine alkaloid extracted in striping solution were 43.76, 75.41 and 52.08 at ph=1.5, ph=2 and ph=3 for striping solution, respectively. the results showed that higher extraction ratio for atropine was at phs=2. it is observed that the ph of the aqueous acceptor phase played an important role on the extraction of atropine values when all the experimental conditions were kept constant except for the ph value of acceptor solution. 5. effect of number of stages increasing the number of stages in rdc design plays an important role to increases the extraction efficiency. the results of atropine extraction using one and two stages are presented in fig. 7. using two stages mean four hydrophilic discs and this will increase the surface area in contact with the feed solution. therefore, atropine alkaloid exhausting from seeds increases and the same increase occurs in membrane. on the other hand, increasing the number of stages leads to an increase in surface area in contact with the striping solution. thus h2so4 0 20 40 60 80 100 0 20 40 60 80 100 120 % a tr o p in e time(min) (a) 5 rpm 10 rpm 15 rpm 0 20 40 60 80 100 0 20 40 60 80 100 120 % a tr o p in e time(min) (b) 5 rpm 10 rpm 15 rpm khalid m. abed -available online at: www.iasj.net ijcpe vol.15 no.2 (june 2014) 81 molecules in membrane are increased. therefore, using two stages gave higher %atropine extract than that from one stage. table 3 shows that increasing the number of stages decreases the rate constant exit k2 while the rate constant entrance k1 increases. fig. 6: effect of ph of stripping solution; a. %atropine in striping phase b. % atropine in feed phase (experimental conditions: phf=9.5, 10 rpm, one stage and 500 ml of n-decane as liquid membrane) table 3: the kinetic parameters for the extraction of atropine at different number of stages number of stages k1 (min -1 ) k2 (min -1 ) (min) (--) (min -1 ) (min -1 ) %atropine in s phase one stage 0.00817 0.0870 30 0.073 -0.00639 0.00639 75.41 two stage 0.00837 0.0860 30 0.075 -0.00652 0.00652 89.93 fig. 7: effect of number of stages; a. %atropine in striping phase b. % atropine in feed phase (experimental conditions: phf=9.5, 10 rpm and 500 ml of n-decane as liquid membrane) 6. effect of the amount of liquid membrane the pertraction study of atropine was carried out in two amounts of liquid membrane 500 and 1000 ml. it can be seen from figure 8 and table 4 that the increase of liquid membrane volume gave negative effect if the surface area is kept constant. if surface area was increased, it may lead to increasing percentage atropine extract because more time is needed for the atropine and sulphate ion to meet together in the membrane to form atropine sulphate. this is shown in figure 8 and table 4. 0 20 40 60 80 100 0 20 40 60 80 100 120 % a tr o p in e time(min) (a) ph=1.5 ph=2 ph=3 0 20 40 60 80 100 0 20 40 60 80 100 % a tr o p in e time(min) (b) ph=1.5 ph=2 ph=3 0 20 40 60 80 100 0 20 40 60 80 100 120 % a tr o p in e time(min) (a) one stage two stage 0 20 40 60 80 100 0 20 40 60 80 100 120 % a tr o p in e time(min) (b) one stage two stage kinetic of alkaloids extraction from plant by batch pertraction in rotating discs contactor 82 ijcpe vol.15 no.2 (june 2014) -available online at: www.iasj.net table 4: the kinetic parameters for the extraction of atropine at different amount of organic liquid membrane amount of membrane k1 (min -1 ) k2 (min -1 ) (min) (--) (min -1 ) (min -1 ) %atropine in s phase 500 ml 0.00817 0.0870 30 0.073 -0.00639 0.00639 75.41 1000ml 0.00722 0.0504 45 0.103 -0.00522 0.00522 19.63 fig. 8: effect of amount of liquid membrane a. %atropine in striping phase b. % atropine in feed phase (experimental conditions: phf=9.5, 10 rpm and n-decane as liquid membrane for one stage) conclusion atropine alkaloid can be transported and extracted by rdc through organic liquid membrane. the percentage of atropine alkaloid extracted by rdc depends on many important parameters such as rate of stirring speed of discs, type of liquid membrane, volume of liquid membrane and ph of feed and striping phases. the extraction efficiency of atropine alkaloid increased with increasing discs rotation speed from 5 to 10 rpm. increasing it to 15 rpm, the percentage of atropine alkaloid decreased because of the increased risk of droplet formation and process deterioration. 89.93 % of atropine was transported when two stages were used. the apparent rate constants, k1 and k2, interfacial transport of extraction and reextraction are determined on the basis of a scheme implying two consecutive irreversible first order reactions. this method offers important advantages such as simplicity and economy. nomenclature notation description rdc rotating disc contactor f feed s stripping k1 entrance rate constant k2 exit rate constant phf ph of feed solution phs ph of striping solution rpm revolution per minute. dcmotor direct current motor. uv ultraviolet visible. cf concentration of atropine in feed solution cf0 initial concentration of atropine in feed solution cm concentration of atropine in liquid membrane cs concentration of atropine in striping solution rf dimensionless concentration in feed solution rm dimensionless concentration in membrane solution 0 20 40 60 80 100 0 20 40 60 80 100 120 % a tr o p in e time(min) (a) 500 ml 1000ml 0 20 40 60 80 100 0 20 40 60 80 100 120 % a tr o p in e time(min) (b) 500ml 1000ml khalid m. abed -available online at: www.iasj.net ijcpe vol.15 no.2 (june 2014) 83 rs dimensionless concentration in striping solution j flux the maximum fluxes of atropine transport in feed phase the maximum fluxes of atropine transport in stripping phase λ wave length tmax the time at which the maximum flux maximum dimensionless concentration in membrane solution eth. eth. ethyl ether references 1ayyad w. al-shahwany, adel a. al-hemiri and khalid m. abed, “comparative evaluation of alkaloids extraction methods from the root bark of punica granatum linn”, journal of advances in bioresearch, vol.4 no.1(2013), p.p. 33-39. 2k. dimitrov, d. metcheva and l. boyadzhiev “ integrated process of extraction and liquid membrane isolation of atropine from atropa belladonna roots” journal of separation and purification technology, vol. 46 (2005), p.p. 41-45. 3ilker akin, serkan erdemir, mustafa yilmaz and mustafa ersoz “calix[4]arene derivative bearing imidazole groups as carrier for the transport of palladium by using bulk liquid membrane” journal of hazardous materials, vol.223-224(2012), p.p.23-30. 4adel a. alhemiri, sawsan a. m. mohammed and raheeq b. alsaadi, “extraction of medicinal compounds from botanicals using bulk liquid membrane in rotating film contactor: recovery of vinblastine from catharanthus roseus”, iraqi journal of chemical and petroleum engineering, vol. 10 no.3 (2009), p.p. 25-30. 5kamiński w. and kwapiński w. “applicability of liquid membranes in environmental protection”, journal of environmental studies, vol.9 no.1 (2005), p.p.37-43. 6vladimr s. k. (2010), liquid membranes principles and applications in chemical separation and wastewater treatment, elsevier science, 1st edition. 7govindaraju muthuraman and mohamed ibrahim “use of bulk liquid membrane for the removal of cibacron red fn-r from aqueous solution using tbab as a carrier”, journal of industrial and engineering chemistry, vol.19 (2013), p.p.444-449. 8krasimir dimitrov, frederique gancel, ludovic montastruc and iordan nikov, “liquid membrane extraction of bio-active amphiphilic substances: recovery of surfactin”, journal of biochemical engineering, vol.42 (2009), p.p.284-253. 9l. boyadzhiev, k. dimitrov and d. metcheva, “integration of solvent extraction and liquid membrane separation: an efficient tool for recovery of bio-active substances from botanicals”, journal of chemical engineering science, vol.61 (2006), p.p.4126-4128. 10g. muthuraman, tjoon tow teng, cheu peng leh and i. norli, “use of bulk liquid membrane for the removal of chromium (vi) from aqueous acidic solution with tri-n-butyl phosphate as a carrier”, journal of desalination, vol.249 (2009), p.p.884-890. 11fazia t. minhas, shahabuddin memon, m. i. bhanger, “transport of hg (ii) through bulk liquid kinetic of alkaloids extraction from plant by batch pertraction in rotating discs contactor 84 ijcpe vol.15 no.2 (june 2014) -available online at: www.iasj.net membrane containing calix [4]arene thioalkyl derivative as a carrier”, journal of desalination, vol.262 (2010), p.p.215-220. 12s.s. madaeni, z. jamali and n. islami, “highly efficient and selective transport of methylene blue through a bulk liquid membrane containing cyanex 301 as carrier”, journal of separation and purification technology, vol. 81 (2011), p.p.116–123. 13siu hua changa, tjoon tow tengb and ismail norli, “cu (ii) transport through soybean oilbased bulk liquid membrane: kinetic study”, chemical engineering journal, vol. 173 (2011), p.p.352– 360. 14adel a. al-hemiri, khalid m. abed and ayaad w. al-shahwany, “extraction of pelletierine from punica granatum l.by liquid membrane technique and modelling”, iraqi journal of chemical and petroleum engineering, vol. 13 no.1 (2012), p.p. 1-9. iraqi journal of chemical and petroleum engineering vol.17 no.3 (september 2016) 4556 issn: 1997-4884 catalytic reforming of iraqi naphtha over pt-ti / hy zeolite catalyst nada s. ahmedzeki*and ban a. al-tabbakh** *chemical engineering department-college of engineering-university of baghdad, baghdad-iraq dr_ahmedzeki@yahoo.com **petroleum research and development center, ministry of oil-baghdad-iraq banaltabbakh@hotmail.com abstract in the present work, zeolite y has been synthesized successfully by sol-gel method.zeolite was synthesized by crystallization of the final gel which consist from seeding and feed stock gels at 85 o c. hy zeolite was prepared by an ion exchange process with ammonium chloride solution and then loaded with different percentages of platinum and titanium by the wet impregnation method. x-ray diffraction (xrd), x-ray florescence (xrf), scanning electron microscopy (sem), bet surface area and, crushing strength were used to characterize the synthesized and prepared catalysts . results showed high crystallinity 90% with silica to alumina ratio 5 for hy, high surface area of 600 m 2 /g and pore volume of 0.38 cm 3 /g. the activity of the prepared zeolite was investigated using a pilot plant unit for the catalytic reforming of iraqi heavy naphtha. all prepared catalysts were investigated at temperatures of 490,500 and 510 o c ,pressure of 20 bar, h2 /hc ratio 3 and lhsv 1.4.hr -1 . reformate was produced with 86 ron and 94% yield at 510ºc and 20 bar using 0.13 wt.% pt 0.75 wt.% ti loaded on synthesized hy. keywords: zeolite y, sol-gel method., naphtha catalytic reforming. introduction catalytic reforming of naphtha is considered as a commercial process to produce high octane gasoline, and the main objective of this process is to transform paraffins and naphthenes of naphtha to aromatic rich product with a little ring opening or cracking as possible [1]. commercial catalysts generally use platinum metal dispersed on porous promoted alumina or silica alumina base both metal and oxide components play an active role [2]. zeolite encompassing mesoporosity and microporosity have many potential applications such as improved catalytic activity and stability in many catalytic reactions [3]. typically, platinum catalysts are used in the reforming of naphtha and because of quick deactivation as a result of coke formation, high university of baghdad college of engineering iraqi journal of chemical and petroleum engineering mailto:dr_ahmedzeki@yahoo.com mailto:banaltabbakh@hotmail.com catalytic reforming of iraqi naphtha over pt-ti / hy zeolite catalyst 46 ijcpe vol.17 no.3 (september 2016) -available online at: www.iasj.net pressures processes and bimetallic catalysts are used to meet the increasing severity requirements such .metallic is rhenium, tin or iridium [1]. catalytic reforming reactions proceed by bi-functional catalyst which include hydrogenation and dehydrogenation reactions are processed on the metallic site while isomerization, cracking and cyclization reactions on the acidic site [4]. as the catalyst should be able to convert the naphtha feed into more favorable products, therefore the catalyst should exhibit strong acidic properties. another support for platinum catalyst is the crystalline aluminosilicate (zeolite) which has specific properties such as ionexchange ability ,high exchange capability , crystalline structure with regular pores and certain ratio of silica to alumina [5]. the bi or multi metallic compounds are usually introduced to the pores of zeolite and reduce to their elemental form with hydrogen under selective condition towards aromatic hydrocarbons, thus the metal is mainly atomically in the pores of zeolite lattice [6]. the objective of the present study is to prepare of zeolite y and converted to hy zeolite after that loading hy zeolite with platinum (0.13 and 0.25 wt. %) and titanium metals ( 0.75, 1 wt.%) by a coimpregnation method. testing of prepared samples for its activity and selectivity in reforming reactions and studying the effect of different metal loadings at pressure of 20 bar and temperature of (490, 500 and 510 ºc) on octane number, reformate yield and percentages of the components in the product. experimental zeoilte preparation sodium aluminate (naalo2), sodium silicate solution (na2sio3) supplied by sigma-aldrich, sodium hydroxide (naoh) by merck were used. zeolite y was synthesized according to sol-gel method. seeding gel is prepared by adding 19.95 gm of deionized water to 4.07 gm of sodium hydroxide and 2.09 gm sodium aluminate [7]. the mixture was stirred in a plastic bottle until dissolved then 28.3gm of sodium silicate solution was added and stirred moderately for at least 10 min. then the seed gel was aged for aging time of 48 hr at room temperature. the feed stock gel was prepared by mixing 131 gm of deionized water, 0.14 gm sodium hydroxide and 13 gm sodium aluminate. stirring was continued in 500 ml plastic beaker until the constituents were completely dissolved, then 178 gm of sodium silicate solution was added with stirring vigorously at 1600 rpm until smooth gel was obtained. the final gel is prepared by adding 16.5 gm of aged seed gel to feed stock gel slowly with mixing up for 20 min. at 1600 rpm. after that the final gel was transferred to a poly propylene bottle and heated in an oven at 85 o c overnight. precipitation occurred until a clear solution was observed indicating complete crystallization. the bottle was opened and left to cool then the wet solid product was set to filtration, washing with distilled water several times until the ph of the filtrate was 9. the product was dried at 110 o c for 24 hr. and then calcined at 500 o c at a rate of 2 o c /min. for 3 hr. ion exchange the acid form of zeolite y was obtained by ion exchange process. 10 gm of zeolite nay was slurried in 200 http://www.iasj.net/ nada s. ahmedzeki and ban a. al-tabbakh -available online at: www.iasj.net ijcpe vol.17 no.3 (september 2016) 47 ml of ammonium chloride solutions with mixing at 70 o c for 2 hr and then left at room temperature overnight. after that the exchanged zeolite was filtered off, washed with deionized water, dried at 110 o c overnight, and then calcined at 525 o c for 3 hr [8], [9]. preparation of pt-ti/hy catalyst a 100 g of prepared hy-zeolite powder was used for preparation of 0.13 and 0.25 wt.% pt and different concentration of ti 0.75,1 by coimpregnation method over hy zeolite. 1.256 g of chloroplatinic acid with 50 ml deionized water and 8.3 ml of titanum butoxide solution after that the hy zeolite was placed under vacuumed condition then the solution was added drop by drop under magnetic stirring until it finished and the vacuum was cut off and the sample was left under mixing for about 2 hr to have a homogenous distribution of metal precursors. then the slurry was filtered, washed with distilled water, dried at 110 o c overnight and calcined for 3 hr at 260 o c at a rate of 2 ºc /min [10], [4]. the catalysts powder were formulated by using granulator machine (multi bowl spheronizer, calvea, england), so 100 g of catalyst was mixed with 15 wt.% of montmorillonite clay as a binder and appropriate amount of water to form a paste which put in the granulator ,then drying overnight at 110 ºc and calcination at 500 ºc for 3 hr. at a rate of 2 ºc / min. the prepared zeolite and catalysts were characterized by different techniques and compared with the commercial type. these techniques include (xrd), (xrf), (sem), (bet). the xrd pattern for powder product was measured using philips diffractometer with cu target at 2 theta value from 560 o at scanning speed of 5 deg / min using cu-kα radiation source of wave length λ=1.5406aº. the chemical composition of zeolite and the metallic loaded weight percent were determined via (xrf) spectro xeros, germany. the morphology was analyzed using sem at different magnification by oxford instrument. bet surface area and pore volume were performed using a micrometrics asap 2020. the samples were degassed for 2 hr under vacuum at 250 o c. catalytic reforming pilot plant unit catalytic activity of pt-ti/hy prepared catalyst was carried out by using catalytic reforming pilot plant unit manufactured by vinci technology / france at petroleum research & development center (prdc) laboratory/ ministry of oil. the unit consists of a fixed bed carbon steel reactor {1.5 m length, 2.5 cm o.d.} with control system and all specifications as shown in figure 1 (a and b). the reactor was charged with 60 g of catalyst and the upper and lower parts were filled with ceramic balls. before the reaction carried out the catalyst was reduced with hydrogen gas at 450 ºc for 3 hr, after that heavy naphtha was pumped and mixed with hydrogen then passed through the catalyst bed to carry out the reaction. feed stock properties are shown in table 1. the product was cooled and separated in a separator to product. the "reformate was collected and analyzed using gc analysis(type, 3300 varian) for paraffin ,aromatic, naphthene concentrations, and for research http://www.iasj.net/ catalytic reforming of iraqi naphtha over pt-ti / hy zeolite catalyst 48 ijcpe vol.17 no.3 (september 2016) -available online at: www.iasj.net octane number "ron" which was measured using portable octane analyzer. fig. 1: a. catalytic reforming unit. (prdc), b. diagram of reforming unit table 1: properties of heavy naphtha properties sulfur content, ppm 1.3 density, g/cm 3 0.74 chemical composition wt.% paraffins 71 aromatics 11 naphthenes 18 ron 57 results and discussion 1. xrd the powder diffraction patterns of zeolite samples confirms the formation of zeolite y phase. figure 2 shows that the characteristic maximum peak of zeolite y at 2 theta of 6.181 is properly distinguished [11]. all other peaks which belong to zeolite y are found in their particular regions, and the crystallinity for the prepared zeolite was 95% as calculated with the reference to the commercial type. comparison indicates that the preparation method result is compatible with crystal structure of zeolite y to conclude that the preparation method gives a good synthesized indigenousness of zeolite y as shown in figure 2 [12]. fig. 2: xrd pattern of synthesized nay zeolite a b http://www.iasj.net/ nada s. ahmedzeki and ban a. al-tabbakh -available online at: www.iasj.net ijcpe vol.17 no.3 (september 2016) 49 2. xrf xrf technique was used to determine the chemical and structural formula of prepared samples and silica to alumina ratio was also calculated from the results of this analysis. the exchange technique was used in this process in one step at constant temperature and the mechanism of ion exchange is shown in figure 3. fig. 3: ion exchange mechanism the degree of ion exchange, silica to alumina ratio and concentration of sodium ion before and after protonation were listed in table 2. table 2: chemical composition of zeolite zeolite nay hy chemical composition , wt.% sio2 59.17 57.96 al2o3 20.1 19.01 na2o 9.3 1.95 sio2/al2o3 molar ratio 5.005 5.183 ion exchange % 79 silica to alumina molar ratio for the prepared zeolite is found equals to 5 and is within the range of type y zeolite [12]. also, the degree of ion exchange was calculated with reference to the percentages of sodium oxide before and after the ion exchange step and was 79 %. 3. surface area and pore volume nitrogen adsorption –desorption were carried out using micromeritics asap 2020 instrument to determine the bet (brunaure emmett teller) surface area and pore volume. after degassing the isotherms is investigated at relative pressure p/po from 0 to 1. surface area and pore volume are also measured. bet surface area is calculated according to this equation: …(1) where sa: surface area m 2 /gm, vm: volume of monolayer m 3 , am: area occupied by one molecular of nitrogen in monolayer is 0.162 nm 2, n: avogadro's number 6.02*10 23 molecules /mole. it can be seen from the isotherms in figure 4 (a, b) that the sample exhibited behavior of type two according to the classification of bet and this type shows large deviation from langmuir model of adsorption and the intermediate flat region in the isotherm correspond to the formation of monolayer. surface area and pore volume were obtained as shown in table 3. table 3: surface area and pore volume of synthesized zeolite surface area m 2 /g langmuir surface area, m 2 /g pore volume cm 3 /g 641.87 925.63 0.379 http://www.iasj.net/ catalytic reforming of iraqi naphtha over pt-ti / hy zeolite catalyst 50 ijcpe vol.17 no.3 (september 2016) -available online at: www.iasj.net fig. 4: a. adsorption isotherm of synthesized nay ., b. bet plot 4. sem na-y zeolite crystal size and morphology were observed by sem. figures 5 to 7 show that the crystalline micrographs of the synthesized zeolite having small average size because of nano sized particles as compared with commercial one and the images show a good agreement with that shown in literature revealing a uniform particle size with regular shape and uniform particle size distribution [13], [14]. afm technique is used to measure the particle size and figures 8 to 10 shows that the average particles size were the nano size of prepared nay zeolite is about 80 nm and for hy b a http://www.iasj.net/ nada s. ahmedzeki and ban a. al-tabbakh -available online at: www.iasj.net ijcpe vol.17 no.3 (september 2016) 51 zeolite is 71 nm while for commercial one is about 91nm [10], [15]. fig. 5: sem images of synthesized nay zeolite fig. 6: sem images of commercial nay zeolite fig. 7: sem images of pt / hy catalysts fig. 8: particle size distribution of synthesized y zeolite with average diameter of 81nm fig. 9: particle size distribution of hy zeolite with average diameter of 72nm fig. 10: particle size distribution of commercial hy zeolite with average diameter of 91nm activity testing the activity of all prepared of catalyst samples were investigated for naphtha reforming reaction and http://www.iasj.net/ catalytic reforming of iraqi naphtha over pt-ti / hy zeolite catalyst 52 ijcpe vol.17 no.3 (september 2016) -available online at: www.iasj.net all properties and the crushing strength which gives a good withstanding through operation were listed in table 4. table .4 properties of prepared catalysts catalyst surface area m 2 /g pore volume cm 3 /g bulk density g/cm 3 crushing strength kg (0.13 wt.% pt, 1wt.% ti)/hy 357 0.38 0.701 1.93 (0.25 wt.% pt, 1wt.% ti)/hy 402 0.209 0.649 0.62 (0.25 wt.% pt, 0.75 wt.% ti)/hy 550 0.392 0.695 1.24 (0.25 wt.% pt, 0.75 wt.% ti)/hy* 575 0.831 0.601 0.82 * commercial zeolite hy 1. effect of temperature and bimetallic loading on ron of reformate reaction temperature is one of the critical operating parameters on catalytic naphtha reforming and by reducing or rising the temperature the octane number (ron) of reformate will be changed. it can be observed from figures 11 to 14 that by increasing the reaction temperature from 490 to 510 ºc the octane number of reformate will be increased from 79 to 86. catalyst with 0.13 pt wt.% & 0.75 ti wt.% gives high ron of 86 at temperature of 510 ºc as compared with ron of 83 for same metallic loading but for commercial hy zeolite at same temperature as shown in figures 13 and 14. this increase in octane number is attributed to increase in aromatics compounds due to dehydrogenation reaction of naphthenes [16], [17]. titanium bounds directly to the surface of zeolite and during calcination of tio2 + reacted with lattice oxygen to give tio2 or tio + in the framework through ti-o-si bonds forming a strong electrostatic fields with polar adsorbate giving a good catalytic activity of zeolite [18]. tio2 contains isolated and tetrahydrally coordinate titanium oxide species in the frame work of zeolite giving more stable catalyst and much higher selectivity towards isomerization and aromatization reactions because ti modified and enhance the hydrogenation dehydrogenation metallic function of pt active site also balancing the total acidity of hy zeolite resulting in an efficient balancing between metallic and acidic function of catalyst. [19]. it can be deduced that ti shows a good activity for all catalyst and the optimum or best results obtained for 0.75 wt% which gives a good sharing active site to pt towards the hydrogenation and dehydrogenation giving high reformate quality. the titanium activity improved the performance of the catalyst and the interesting point that it lowers the need of the typical platinum loading of 0.3% in the commercial type. fig. 11: research octane number for product reformate for catalyst 0.13 pt wt.%1 ti wt.% /hy http://www.iasj.net/ nada s. ahmedzeki and ban a. al-tabbakh -available online at: www.iasj.net ijcpe vol.17 no.3 (september 2016) 53 fig. 12: research octane number of product reformate for ( 0.25 pt wt.% -1 ti wt.%) / hy fig. 13: research octane number of product reformate for (0.13 pt wt.% , 0.75 ti wt.%) / hy fig. 14: research octane number of product reformate for (0.13 pt wt.% , 0.75 ti wt.%) / commercial hy fig. 15: tio2 incorporation into the framework structure of zeolite [18] 2. effect of temperature and bimetallic loading on distribution of reformate hydrocarbons catalytic naphtha reforming showed to proceed a typical bifunctional reactions occurred on both metallic site represented by pt and ti and the acidic site represented by hy zeolite. figure 16 shows a possible mechanism [20]. fig. 16: mechanism on metalic and acidic sites of bifunctional catalysts [20] as in this research although hy zeolite catalyst exhibited a hydrophobic properties derived from high sio2 / al2o3 ratio, the tio2 loading on pt / http://www.iasj.net/ catalytic reforming of iraqi naphtha over pt-ti / hy zeolite catalyst 54 ijcpe vol.17 no.3 (september 2016) -available online at: www.iasj.net hy result a higher hydrophobicity leading to achieve efficient activity. for all tested catalyst it can be observed that at high temperature the selectivity towards aromatics increases and also a better performance was obtained at low level of metal loading as shown in figures 19 and 20. the same conclusions were found from the study of regali, (2014) [21]. another advantage of the bimetallic loading in the composite catalyst could be related to that titanium may form an alloy with platinum preventing the increase in platinum crystallites size and keeping it well dispersed (prevent sintering) also preventing of coke precursors to deposit onto the surface of catalyst [22]. finally from all results it can be deduced that ti shows a good activity for all catalyst and the optimum or best results obtained for 0.75 wt% which gives a good sharing active site to pt towards the hydrogenation and dehydrogenation giving high reformate quality. the titanium activity improved the performance of the catalyst and the interesting point that it lowers the need of the typical platinum loading of 0.3% in the commercial type. fig. 17: product distribution for (0.13 pt wt.% 1 ti wt.%) / hy at different temperatures fig. 18: product distribution for (0.25 pt wt.% 1 ti wt.%) / hy at different temperatures fig. 19: product distribution for (0.13 pt wt.% 0.75 ti wt.%) / hy at different temperatures fig. 20: product distribution for (0.13 pt wt.% 0.75 ti wt.%) / commercial hy at different temperatures 3. effect of reforming conditions on reformate yield in catalytic reforming the yield of reformate is defined as the volume of product reformate to the volume of heavy naphtha feed and the results showed high reformate yield obtained http://www.iasj.net/ nada s. ahmedzeki and ban a. al-tabbakh -available online at: www.iasj.net ijcpe vol.17 no.3 (september 2016) 55 ranges from 91 to 95 for all catalyst investigated as shown in figure 21. fig. 21: yield of product reformate for different catalyst conclusions as a result of this work these conclusions have been made:  a very good crystallinity of 90% ,silica to alumina molar ratio of 5 and bet surface area of 600 m 2 /g has been obtained for synthezied zeolite .  high octane number of 86 is obtained at temperature of 510 ºc for 0.13wt.% pt and 0.75wt.% ti /hy catalyst.  titanium loading on zeolite was found to give a good activity with loading 0.75 wt.% ti which also has an important results from economic point of view in reducing the percentage of platinum loading to 0.13 wt.% pt compared with commercial type of 0.3 wt.%pt. acknowledgment the authors are gratefully acknowledging the iraqi ministry of higher education for the financial support. also, the authors thank the izmir institute of technology in turkey for implementing the characterization analysis. the authors are very grateful to the petroleum research and development center (prdc)-ministry of oil in iraq for their effort in performing the catalytic activity test for naphtha reforming. references 1. lee sunggyu ,"encyclopedia of chemical processing '[book]. new york : taylor & francis group , 2006. 2. laizet j.b. soiland a.k. , leglise j. and duchet j.c. [journal] // topics in catalysis. 2000. vol. 2000. p. 89. 3. mohammed r. r. mitra j., davood . "progress in catalytic naphtha reforming", [journal] // applied energy. 2013. vol. 109. pp. 7993. 4. alrawi u. s. "hydroconversion of n-hexane over platinum supported zeolite catalysts prepared by super creitical technique" : ph.d thesis , nahrain university, 2008. 5. abdul rahman b. "isomerization of n-hexane over platinum supported catalyst by using some monitoring agents": msc. thesis , nahrain university, 2000. 6. thomas c.l. "catalytic processes and proven catalyst", [book]. new york : [s.n.], 1979. 7. rahman m.m., awang m.b. , yusof a.m. "preperation ,charecterization and application of zeolite na-y for water filteration " [journal] // australian journal of basic and applied scinces.—2012, vol.6.-pp.50-54. 8. mohammed a.a. gaib.m., nasief m. "effect of promoters on the catalytic activity of the isomerization catalyst" [journal] // iraqi journal of chemical and petroleum engineering. 2008. vol. 9. pp. 9-14. 9. pedrosa a.m. marcelo j.b., dulce m.a.,antonio s.a. "colbalt and nickel supported on hy zeolite :synthesis ,characterization and catalytic properties" [journal] // 88 90 92 94 96 r e fo rm a te y ie ld reaction temperature, ºc. cat. (0.13 pt wt.% 1 ti wt.%) / hy cat. (0.25 pt wt.% 1 ti wt.%) / hy cat. (0.13 pt wt.% 0.75 ti wt. % ) / hy cat. ( 0.13 pt wt.% 0.75 ti wt.% ) / com. hy http://www.iasj.net/ catalytic reforming of iraqi naphtha over pt-ti / hy zeolite catalyst 56 ijcpe vol.17 no.3 (september 2016) -available online at: www.iasj.net materails research bulletin. 2006. vol. 41. pp. 1105-1111. 10. gulic h. "liquid phase hydrogenation of citral on zeolite supported monometalic (ni,pt) and bimetalic (ni-sn, pt-sn) catalysts.": ms.c. thesis, izmir institute of technology : [s.n.], 2005. 11. breck d.w." zeolite molecular sieves ,structure chemistry &use:, [book],john wiley & sons, newyork,1984. 12. nsaif m., abdulhaq a., farhan a., neamat s."catalytic cracking of heptane using prepared zeolite " [journal] // journal of asian scinentific research , 2012., vol. 12, pp.927-948. 13. htay m.m. mya o. "preparation of zeolite y catalyst for petroleum cracking", [journal] // world academy of science and engineering and technology. 2008. vol. 48. pp. 114-120. 14. mohamed a.m. ezzat a. "synthesis of faujasite from egyptian clays: characterization & remval of heavy metals", [journal] // geomaterails. 2015. vol. 5. pp. 68-76. 15. emre k. "an investigation of activities and selectivities of hzsm-5 and h-ferrite zeolite modified by different method in nbutene isomerization": ms.c. thesis , izmir institute of technology : 2010. 16. rase h.f." case studies and design data , case study 108 catalytic reforming" [book section] // chemical reactor design for process plant. usa : john wiley & sons, 1972. 17. vadi m. hoseinzadeh a. "catalytic reforming of n-heptane on pt-ti supported on gamma alumina" , [conference] // international conference on food and biotechnology. singapore : 2012. pp. 69-72. 18. chen h. matsumto a., nishimiya n., tsutsumi k. "preparation and characterzation of tio2 incorporated y zeolite" [journal] // collids and surfaces:physiochemical and engineering aspects. 1999. vol. 157. pp. 295-305. 19. yasutaka k. tetsutaro o., kosuke m.,iwao k., hiromi y. "xafs study on tio2 photocatalyst loaded zeolite synthesiszed from steel slag." division of materail & manufacturing science, 2004. 20. galperin l.b. bricker j.c., holmgren j.r. "effect of support acid-basic properties on activity and selectivity of pt catalysts in reaction of methylcyclopentane ring opening". [journal] // applied catalysis. 2003. vol. 239. pp. 297-304. 21. regali f. leonardo f. l., anna m. v., magali b., sve j. "hydroconversion of n-hexadecane on pt/silica alumina catalysts, effect of metal loading andsupport acidity on bifunctional and hydrogenolytic activity", [journal] // applied catalysis. 2014. vol. 469. pp. 328-339. 22. george a. arpad m. "hydrocarbon chemistry "[book]. new jersy : jonhn wiley & sons., 2003. http://www.iasj.net/ ijcpe vol.9 no. 2 (june 2008) iraqi journal of chemical and petroleum engineering vol.9 no.2 (june 2008) 1-8 issn: 1997-4884 the relationships between the physical and chemical properties of narrow fractions distilled from mixed kirkuk and sharki-baghdad crude oils abdul-halim abdul-karim mohammed * , hadi g. attiya, and hayder abdul khaliq khudair * chemical engineering department college of engineering university of baghdad – iraq abstract mixed kirkuk and sharki-baghdad crude oils were distilled into narrow fractions. the range of these narrow fractions were 10 o c, starting from ibp to 350 o c. the total distillates from mixed kirkuk and sharki-baghdad crude oils were 58.25 vol % and 44.65 vol %, respectively.the hydrocarbons compositions (paraffin, naphthene, aromatic) in light fractions starting from ibp to 250 o c were determined by using pona analysis method. the results show that the paraffin content decreases with increasing mid percent boiling point of the fraction, while the naphthene, and aromatic increase with the increase of mid percent boiling point of mixed kirkuk and sharki-baghdad crude oils. three groups of empirical equations were developed for the prediction of hydrocarbons compositions (paraffin, naphthene, aromatic) based on physical properties (mid percent boiling point, specific gravity, and refractive index) of narrow fractions distilled from mixed kirkuk and sharki-baghdad crude oils. the first group relates the mid percent boiling point with the specific gravity, the second group relates the mid percent boiling point with the refractive index, while the third group relates the specific gravity with the refractive index. keywords: petroleum fractions analysis, hydrocarbons content in crude oil, pona analysis, sulfonation method introduction crude oils and refined petroleum products consist largely of hydrocarbons, which are chemicals composed solely of hydrogen and carbon in various molecular arrangements. crude oils contain hundreds of different hydrocarbons and other organic and inorganic substances including atoms of sulfur, nitrogen, and oxygen, as well as metals such as iron, vanadium, nickel, and chromium [1, 2]. petroleum fractions are mixture of many hydrocarbons from different families. the most common hydrocarbon types available in petroleum fraction are paraffin, naphthene, and aromatic. properties of hydrocarbons vary with carbon number or molecular weight as well as family type. riazi and daubert [3] have shown that a minimum of two parameters are required to get estimation of other physical properties. the most appropriate parameters are boiling point and specific gravity at 15.5°c. these two parameters are mainly available for petroleum fraction. other properties may be available from laboratory measurements are refractive index, density at 20°c, and kinematic viscosity [3]. studies of the nature and the type of hydrocarbon constituents in crude petroleum can be carried out by pona analysis. pona analysis can be used for light university of baghdad college of engineering iraqi journal of chemical and petroleum engineering the relationships between the physical and chemical properties of narrow fractions distilled from mixed kirkuk and sharki-baghdad crude oils 2 ijcpe vol.9 no. 2 (june 2008) fractions (from ibp to 250°c) and depended on sulfonation and aniline point after and before sulfonation. lipkin and kurtz[4] [1941] calculated the weight percent of naphthenic ring in saturated hydrocarbons, based on density and molecular weight, using equations (1) and (2). wt % ring = (a+190.0 d – 217.9) / (0.539 d – 0.249) (1) (for d < 0.861) wt % ring = (a+102.8 d – 142.8) / (0.262) (2) (for d > 0.861) a: was determined by equation (3). a = 55.3 + (3516) / (mol wt + 12) (3) (for mol wt >100) molecular weight is obtained with sufficient accuracy from correlation based on density and boiling point, density and viscosity, or viscosities at two temperatures. groenings, kurtz, and sankin [1945] used the refractive dispersion and bromine number for the determination of aromatic content of cracking naphtha by equation [4]. wt % aromatic = (δ sample – 0.16 br -99) / (δ aromatic – 99) (4) rossini, rampton, and gooding [1946] show that the molecular-weight range, specific dispersion of the lubricating oil can be used as measure of the presence or absence of aromatic rings. values of specific gravity below 100 are usually accepted as meaning that the sample is aromatic free [5]. gooding [1946] had used the refractivity intercept for the determination of aromatics in straightrun fractions [6]. van nes and van weston[7] show that the percent ring carbons in the hydrogenated fractions from five crude oils can be determined accurately from refractivity intercept correlation. they also showed that there is an approximate relation between viscosity gravity constant (vgc) and percent paraffin carbon, percent naphthene carbon and percent aromatic carbons. equation (5) described this relation. vgc = 0.00743 % cp + 0.00925 % cn + 0.0110 ca (5) kesler-lee, in 1976, predicted the physical properties of petroleum fractions such as molecular weight, critical temperature, and critical pressure based on boiling point and specific gravity of fractions as input data [8]. hajek, and skelnar, in 1978 analyzed heavy crude oil using nmr spectroscopy and they determined the amount of aromatic and aliphatic carbon [9]. misbah and mohammad (1983) estimated the aliphatic and aromatic content, average paraffinic chain length, and hydrogen, methyl and alkyl bearing aromatic carbons for six fractions of saudi arabian heavy crude oils based on n.m.r. spectroscopy [10]. riaze and daubert, in 1987, proposed a general empirical correlation to predict physical properties of pure hydrocarbons and undefined petroleum fractions. these correlations are applicable in the molecular weight range 70–300 and normal boiling point range 32– 210o c [11]. riazi and sahhaf, in 1995, proposed an empirical correlation for the calculation of critical properties of heavy petroleum fraction based on molecular weight and pna as input data [12]. experimental work in this work empirical correlations to predict paraffin, naphthene, aromatic content of petroleum fraction based on simple physical properties such as mid percent boiling point, specific gravity, and refractive index were developed. feed stocks the feed stocks used in this investigation were mixed kirkuk and sharki-baghdad crude oils. the properties of mixed kirkuk and sharki-baghdad crude oils are given in table 1. abdul-halim abdul-karim mohammed*, hadi g. attiya, and hayder abdul khaliq khudair 3 ijcpe vol.9 no. 2 (june 2008) table 1 property of mixed kirkuk and sharkibaghdad crude oils item tests mixed kirkuk crude oil sharkibaghdad crude oil 1 specific gravity at 15.6/15.6 o c 0.8810 0.9296 2 api gravity 29.1 20.6 3 r.v.p. at 37.8 o c, psi 2.2 ---- 4 salt content, mg/l 15.2 26.4 5 pour point, o c -9 -24 6 water content, vol % nil 0.2 7 c.c.r, wt % 5.4 8.1 8 h2s content, ppm 7.73 12.8 9 total sulphur content, wt % 3.3 3.39 10 astm distillation, vol % recovery at ibp 50 o c 75 o c 100 o c 125 o c 150 o c 175 o c 200 o c 225 o c 250 o c 275 o c 300 o c total distillate, vol % total residue, vol % 57 --- 0.6 4.6 9.6 14.6 20.6 26.3 31.3 36.0 42.0 46.3 48.4 50.6 62 --- 2.3 5.0 7.0 9.3 12.3 17.3 20.6 24.0 28.3 36.3 37.6 61.4 distillation unit distillation of mixed kirkuk and sharki-baghdad crude oils into narrow fractions (every 10°c) was achieved in laboratory distillation unit according to astm d 2892-78 consisting of distillation flask, heating mantle, distillation column, condenser, timer, reflux divider, thermometers, fraction collector, variac, gauge pressure, and vacuum pump. the size of distillation flask was 6 liters, and provided with two side arm, the first side arm was used to charge the crude oil and the second sidearm contains glass bulb for thermometer. the distillation flask was mounted with 2.4 kw heating kettle connecting with variac to control the heat input to the flask. the distillation column consisted of 10 trays, and has 40 mm inside diameter and 450 mm length. the column was isolated by highly vacuum jacket to minimize the heat loss. reflux ratio was controlled by using a magnetic valve connected with reflux timer. a reflux ratio 5:1 was used for atmospheric distillation and 3:1 for vacuum distillation. the vacuum was achieved by using vacuum system consisted of vacuum pump, trap, and vacuum gauge. when the temperature of crude oil inside the distillation flask reach 300oc, the distillation column is connected with the vacuum system. the vacuum system lines for both the condenser and the receiver are gathered by t shape joint to produce 100 mm pressure. vacuum pump type edward, 2008, ges machines ltd, was used for vacuum production. pona analysis this method was used for light fractions (ibp to 250 °c) to determine the aromatic, naphthene, and paraffin content. aromatic determination was achieved by sulfonation method; naphthene by empirical equation and paraffin by subtracting aromatic and naphthene % from 100. determination of aromatic the sulfonation method was used to separate the aromatic-olefin fraction from distillated fraction by using concentrated sulfuric acid according to (astm d 101968). the apparatus was used for this method consists of sulfonation flask, pipette of 10-ml, cooling bath, and thermometer. the relationships between the physical and chemical properties of narrow fractions distilled from mixed kirkuk and sharki-baghdad crude oils 4 ijcpe vol.9 no. 2 (june 2008) the sulfonation flask is made of heat resistance glass. the calibrated neck of the flask is graduated from zero to 100 in 2 increments. estimation of naphthenes and paraffines the estimation of the percentage of naphthenes was done by the determination of the aniline point of the fraction before and after removing the aromatic fraction [9]. naphthenes percentages were calculated from equation [6,9]. n % = (ap – as) / (ap – an) * 100 (6) the paraffines percentage were calculated by equation 7 p % = 100 – (a % + n %) (7) aniline point the aniline point of all narrow fractions produced from crude oil distillation unit was determined according to astm d 611-82. 5 ml of aniline with 5 ml of the tested sample were added in the test tube and mixed by stirrer and the heat was supplied to heat bath until homogenous one phase of sample and aniline was obtained. the sample then cooled until the appearance of two phases. the measured temperature at two phase appearance is called aniline point. density and specific gravity density, specific gravity of all narrow distillation fractions from mixed kirkuk and sharki-baghdad crude oils were determined according to astm d 1298-80, by using 25 cm 3 pycnometer. refractive index refractive index of all narrow fractions of mixed kirkuk and sharki-baghdad crude oils were determined according to astm d 1218-82. the apparatus used consisted of abbe refractometer having rang 1.33 to 1.64 for the sodium d line, thermometer for recording temperature, circulating pump and chiller to keep the temperature at 20°c. results and discussion true boiling point of mixed kirkuk and sharkibaghdad crude oils: figures 1 and 2 show the true boiling point curves of mixed kirkuk and sharki-baghdad crude oils, respectively. temperature, c d is ti lla te , % 0 1 0 2 0 3 0 4 0 5 0 6 0 0 5 0 1 0 0 1 5 0 2 0 0 2 5 0 3 0 0 3 5 0 4 0 0 v o l % m a ss % fig. 1: true boiling point curve of mixed kirkuk crude oil temperature, c d is ti lla te , % 0 1 0 2 0 3 0 4 0 5 0 0 5 0 1 0 0 1 5 0 2 0 0 2 5 0 3 0 0 3 5 0 4 0 0 v o l % m a s s % fig. 2: true boiling point curve of sharki-baghdad crude oil relationship between mid percent boiling point with specific gravity and api: figure 3 shows the relation between the specific gravity values with mid percent boiling point temperature of the narrow fractions distilled from mixed kirkuk and sharki-baghdad crude oils. the specific gravity of the narrow fractions increases with the increase of mid percent boiling point of the fractions. this is due to the increase of the aromatic and decrease of paraffinic content, and this is in agreement with nelson. [14] usually the specific gravity of aromatic hydrocarbon is higher than those for paraffin hydrocarbon having the same number of carbon atoms. figure 4 shows the abdul-halim abdul-karim mohammed*, hadi g. attiya, and hayder abdul khaliq khudair 5 ijcpe vol.9 no. 2 (june 2008) relation between the degree api gravity with the mid percent boiling point temperature of the narrow fractions distilled from mixed kirkuk and sharki-baghdad crude oils. degree api gravity decrease, with the increase of mid percent boiling point temperature of the narrow fractions, because the value of api is inversely related to specific gravity. fig. 3: relation between mid percent boiling point of the narrow fraction with the specific gravity figure 4: relation between mid percent boiling point of the narrow fraction with the degree api relationship between mid percent boiling point and refractive index: figure 5 shows the relation between the refractive index of the distilled narrow fractions with mid percent boiling temperature of mixed kirkuk and sharki baghdad crude oils. it was noted that the refractive index increases with the increase of mid percent boiling point temperature of the fractions because the refractive index of high molecular weight hydrocarbon is higher than that for low molecular weight fractions [15]. the results show that the refractive index of the narrow fractions up to 200°c distilled from both crude oils is approximately the same and the difference in ri value increases after 200°c. this is because the higher naphthenic hydrocarbons content of sharki-baghdad crude oil narrow fraction compared with fractions distilled from mixed kirkuk crude oil (see fig 8). figure 5 relation between mid percent boiling point of the narrow fraction with the refractive index fig. 5: relation between mid percent boiling point of the narrow fraction with the refractive index relationship between mid percent boiling point and aniline point: figure 6 shows the relation between mid percent boiling point and the aniline point of narrow fraction of mixed kirkuk and sharki-baghdad crude oils. the results show that the aniline point increases with the increase of mid percent boiling point of the narrow distillated fractions and this is due to the increase of molecular weight of the fractions (14). figure 6 relation between mid percent boiling point of the narrow fraction with the aniline point mid percent boiling point temperature,c s p e c if ic g ra v it y 0 .6 2 0 .6 6 0 .7 0 0 .7 4 0 .7 8 0 .8 2 0 .8 6 0 .9 0 0 .9 4 2 0 8 0 1 4 0 2 0 0 2 6 0 3 2 0 3 8 0 m i xe d k i rku k cru d e o i l s h a rki _ b a g h d a d cru d e o i l mid percent boiling point temperature, c d e g re e a p i g ra v it y 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 2 0 8 0 1 4 0 2 0 0 2 6 0 3 2 0 3 8 0 m i xe d k i rku k cru d e o i l s h a rki -b a g h d a d cru d e o i l mid percent boiling point, c a n il in e p o in t, c 5 2 5 6 6 0 6 4 6 8 7 2 7 6 2 0 8 0 1 4 0 2 0 0 2 6 0 3 2 0 3 8 0 m i xe d k i rku k cru d e o i l s h a rki -b a g h d a d cru d e o i l mid percent boiling point temperature, c r e fr a c ti v e i n d e x 1 .3 6 1 .3 8 1 .4 0 1 .4 2 1 .4 4 1 .4 6 1 .4 8 1 .5 0 1 .5 2 2 0 8 0 1 4 0 2 0 0 2 6 0 3 2 0 3 8 0 m i xe d k i rku k cru d e o i l s h a rki -b a g h d a d cru d e o i l the relationships between the physical and chemical properties of narrow fractions distilled from mixed kirkuk and sharki-baghdad crude oils 6 ijcpe vol.9 no. 2 (june 2008) fig. 6: relation between mid percent boiling point of the narrow fraction with the aniline point effect of narrow fraction boiling point on the hydrocarbon content: figure 7 shows the relation between mid percent boiling point of the distillate fractions and the paraffin content of mixed kirkuk and sharki-baghdad crude oils. the result shows that the paraffin content decreases with the increasing of mid percent boiling point of the narrow fractions. figure 8 shows the relation between mid percent boiling point of the distillate fractions and the naphthene content of mixed kirkuk and sharki-baghdad crude oils. the result shows that the naphthene content increases with increasing mid percent boiling point of the narrow fractions. this agrees with the results of hajek and others (35) . figure 9 shows the relation between mid percent boiling point and the aromatic content of narrow fractions distilled from mixed kirkuk and sharki-baghdad crude oils. its noted that the aromatic content of mixed kirkuk narrow fractions less than the sharki-baghdad narrow fractions. the result also shows that the aromatic content increases with increasing mid percent boiling point of the narrow fractions. these results agree with those obtained by other authors [14,16]. fig.7: relation between mid percent boiling point of the narrow fraction with the paraffin content fig. 8: relation between mid percent boiling point of the narrow fraction with the naphthene content fig. 9: relation between mid boiling point of the narrow fraction with the aromatic content prediction of hydrocarbon composition based on physical properties of narrow fractions: raize and daubert were proposed a general equation (4.1) for the estimation of some important properties from other simple properties [11]. 3 2 2 11 aa a   (4.1) where:  = property needed to predict 21 , = simple physical properties a1, a2, a3= constants raize and doubert were estimated the molecular weight, critical temperature, critical pressure and a centric factor of wide range fraction distilled from some american crude oils based on specific gravity and boiling point [11]. based on the general equation (4.1) some new relationships for the prediction of hydrocarbon composition of narrow fractions distilled from mixed kirkuk and sharki-baghdad crude oils were developed. a computer program package (statistica) was used to develop the necessary correlations. the program performs least square fitting of a proposed function for given set of data. mid boiling point temperature, c p a ra ff in e , v o l % 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 4 0 8 0 1 2 0 1 6 0 2 0 0 2 4 0 2 8 0 m i xe d k i rku k cru d e o i l s h a rki -b a g h d a d cru d e o i l mid boiling point temperature, c n a p h th e n e , v o l % 0 5 1 0 1 5 2 0 2 5 3 0 3 5 4 0 4 5 4 0 8 0 1 2 0 1 6 0 2 0 0 2 4 0 2 8 0 m i xe d k i rku k cru d e o i l s h a rki -b a g h d a d cru d e o i l \ mid boiling point temperature, c a ro m a ti c , v o l % 0 6 1 2 1 8 2 4 3 0 4 0 8 0 1 2 0 1 6 0 2 0 0 2 4 0 2 8 0 m i xe d k i rku k cru d e o i l s h a rki -b a g h d a d cru d e o i l abdul-halim abdul-karim mohammed*, hadi g. attiya, and hayder abdul khaliq khudair 7 ijcpe vol.9 no. 2 (june 2008) table (4.1) shows the relationships for the estimation of hydrocarbon composition for narrow fractions distilled from mixed kirkuk crude oil, while table (4.2) shows the relationships for narrow fractions distilled from sharkibaghdad crude oil. equations (1, 2) and (3) relates the percent of paraffin, naphthene and aromatic, respectively with the mid boiling point and specific gravity of narrow fractions distilled from mixed kirkuk crude oil, while equations (10, 11) and (12) related the same properties for narrow fractions distilled from sharki-baghdad crude oil. equations (4, 5) and (6) relates the percent of paraffin, naphthene and aromatic, respectively with the mid boiling point and refractive index of narrow fractions distilled from mixed kirkuk crude oil, while equations (13, 14) and (15) related the same properties for narrow fractions distilled from sharki-baghdad crude oil. equations (7, 8) and (9) relates the percent of paraffin, naphthene and aromatic, respectively with the specific gravity and refractive index of narrow fractions distilled from mixed kirkuk crude oil, while equations 16, 17 and 18 related the same properties for narrow fractions distilled from sharki-baghdad crude oil. table 4.1 predict equations of mixed kirkuk crude oil no equation a1 a2 a3 r 1 p=a1 t a2 s a3 7503.86 -0.7885 2.54 0.93 2 n= a1 t a2 s a3 0.015 1.368 0.029 0.98 3 a= a1 t a2 s a3 92e-6 2.176 -2.508 0.974 4 p= a1 t a2 ri a3 564.83 -0.398 -0.241 0.93 5 n= a1 t a2 ri a3 0.0296 1.55 -4.508 0.98 6 a= a1 t a2 ri a3 418e-6 1.539 6.677 0.97 7 p= a1 s a2 ri a3 3286.5 0.1966 -10.59 0.93 8 n= a1 s a2 ri a3 23396.6 12.369 -10.96 0.98 9 a= a1 s a2 ri a3 1e-7 -2.2574 52.163 0.96 table 4.2 predict equations of sharki-baghdad crude oil conclusions the total distillate from mixed kirkuk crude oil was 50.29 wt % while the total distillate from sharki-baghdad was 37.64 wt %, and thus denoted that mixed kirkuk crude oil lighter than sharki-baghdad crude oil. paraffinic content decreases with the increasing mid percent boiling point of the narrow fractions, while naphthenic and aromatic contents increase with the increasing mid percent boiling point of the fraction. the specific gravity, refractive index of the narrow fractions increase with increasing the mid percent boiling point of the fractions. the predicted equations of hydrocarbon group based on mid percent boiling point and specific gravity were identical for both the mixed kirkuk and sharki-baghdad crude oils, while the equations based on specific gravity and refractive index and those based on the mid percent boiling point and specific gravity has were identical for mixed kirkuk and sharki-baghdad crude oils. acknowledgment i wish to express my sincere appreciation and utmost gratitude to my supervisor prof. abdul-halim a.-k. mohammed for this guidance and encouragement in directing this work. nomenclature a aromatic an aniline point of naphthenic hydrocarbon, °c ap aniline point of paraffinic hydrocarbon,°c astm american standard test measurement br bromine number ccr conradson carbon residue d density at 20 oc in g / ml g specific gravity ibp initial boiling point m moleculer weight n naphthene p paraffin pna paraffin naphthene aromatic ri refractive index rvp reid vapor pressure sp.gr specific gravity t average boiling point temperature in °c tbp true boiling point vgc viscosity gravity constant δ refractive dispersion the relationships between the physical and chemical properties of narrow fractions distilled from mixed kirkuk and sharki-baghdad crude oils 8 ijcpe vol.9 no. 2 (june 2008) reference 1. types of petroleum oils (http://www. oil program, us epa.htm),(2003). 2. hobson, g. d., "modern petroleum technology", 4th ed., applied science publish ltd., great britain (1975). 3. selection of a characterization scheme for hydrocarbon system in process simulators (http://www. oil industry.pdf.htm), (2003). 4. lipkin, m. r. and kurtz, s. s., jr., ind. eng. chem., 13,291 (1941). 5. ranpton, h. c., j. inst. pet., 39, 354, (1946). 6. gooding, r. m., adams, n.g. and rall, h. t., ind. eng.chem. anal.ed., 18, 2 (1946). 7. van nes, k. and van weston, h. a., "aspects of the constitution of mineral oil" , pp.306-7, new york, elsevere, 1951. 8. kesler, m. g., and lee, b. i., hydro. proc., 55, 153, (1976). 9. hajek, m., skelnar, v., and lang, i., anal. chem. 50, 773, (1978). 10. misbah, u. h., and mohammad, f. a., fuel, 62, 518, (1983). 11. riazi, m. r., and daubert, t. e., ind. eng. chem. res., 26, 755, (1987). 12. riazi, m. r., and sahhaf, t. a., ind. eng. chem. res., 34, 4145, (1995). 13. arix, v. n., rasian, m. g., and roodin, m. g., chemistry and technology of petroleum and gas, chimiya publisher, (1977). 14. nelson, w. l. "petroleum refinery engineering", 4th ed., mcgraw-hill, new york (1958). 15. john, m. h., "petroleum geochemistry and geology", (1979). 16. gary, j. h. and handwerk, g.e.,"petroleum refining, technology and economics", 2nd ed., mareel dekker inc. (1984) ijcpe vol.9 no.1 (march 2008) 1 iraqi journal of chemical and petroleum engineering vol.9 no.1 (march 2008) 1-8 issn: 1997-4884 a quantitative analysis of the mixing of three solids different in density by an air fluidized bed abbas h. sulaymon* and rasha habeb salman** * environmental engineering department college of engineering university of baghdad – iraq ** chemical engineering department college of engineering university of baghdad – iraq abstract three cohesionless free flowing materials of different density were mixed in an air fluidized bed to study the mixing process by calculating performance of mixing index according to rose equation (1959) and to study the effect of four variables (air velocity, mixing time, particle size of trace component and concentration of trace component) on the mixing index and as well as on mixing performance. it was found that mixing index increases with increasing the air velocity, mixing time and concentration of trace component until the optimum value. mixing index depends on the magnitude of difference in particle size the first set of experiments (salt then sand then cast iron) give higher mixing index and better performance of mixing than the second set of experiments (sand then salt then cast iron). box-willson method was used to minimize number of experiments and to represent the relationship between the variables. keywords: quantitative analysis, fluidized bed, mixing, solid introduction mixing is the treatment of two or more components in such away that the individual particles of the different components in the mixture are evenly distributed and lie adjacent to each other within the highest possible probability [1]. mixing is important and essential component in many operations. material properties and the quality of the final products are highly dependent on equipment mixing performance [2]. particles will change their relative positions only when subjected to movement. once movement begins, the particles may randomize or segregate depending on both the type of movement imposed on the system and on the physical characteristics of the constituent [3]. there are many different types of mixers are used in the mixing of solids materials and in the present study an air fluidized bed was used. gas fluidized beds are successfully applied to different physical and chemical processes, for example solids mixing, solids drying, catalytic oil cracking and coal combustion. it is important for the modeling of processes occurring in fluidized beds to have knowledge about the nature of the fluidized particles, how they move, how, if at all, they make contacting and how segregation of a typical particles takes place [4]. university of baghdad college of engineering iraqi journal of chemical and petroleum engineering a quantitative analysis of the mixing of three solids different in density by an air fluidized bed ijcpe vol.9 no.1 (march 2008) 2 in fluidized beds, particles of different size and / or density are moving to reach other; equilibrium is set up between the competitive mechanisms of mixing and segregation. this leads to a variation in solid composition over the height of the bed, the flotsam tending to rise and the jetsam tending to sink. the comprehensive study of single and binary component systems has shown that particle movement is caused solely by the bubbles [5]. some of the previous studies had shown that solid materials could be classified according to burak classification about role of division of powder. it had been suggested by burak that particles below 100 μm are nearly always cohesive, particles above 400 μm are generally freeflowing and particles with sizes between 100 and 400 μm may be free-flowing or cohesive [6]. it was found that material pairs could be grouped as “easy” or “difficult” mixtures depending upon the absence of segregation tendency. “non-easy” mixtures were produced whenever differences in specific gravity and/or particles size occurred between the two mixture components [7]. statistical analysis has been a major tool of solids mixing investigations because of the random nature of mixing process. the statistical degrees of mixing are essentially different forms of the mean deviation, standard deviation or variance [8]. rose [9] proposed an expression to evaluate the degree of mixing: m=1-(δ/δo) (1) where:  1 xx o  (2)        n i i n xx 1 2 1  (3)    ni ii n x n x 1 1 (4) which, it is the most appropriate to determine the final state of a mixture, this was approved by yano and sano when they set up nine expressions for the degree of mixing and they compared the particular definitions using the experimental data. the mixing degree defined by rose (eq. 1) can be applied only when the mixing value scale has been specified. a scale thus specified is proposed and presented in table 1 [10]. the developed experimental models can be used widely for analyzing the mixing and segregation characteristics of the homogeneous binary mixtures of particles over a good range of the operating parameters [11]. table 1 proposed scale of mixture quality [10] quality of mixture boundary value of m bad 0.7 un-satisfactory 0.7 – 0.8 fairly good 0.8 – 0.9 good 0.9 – 0.94 very good 0.94 – 0.96 excellent > 0.96 mixing process is usually followed by sampling in order to assess the process. unlike liquid mixing, which can always produces a homogenous mixture; solids mixing always produce an inhomogeneous mixture. therefore, the most important and desirable step is to get samples represent the whole mixture. however, there is always difference between the sample and the mixture. the aim of this research is to achieve efficient mixing. experimental work application of box-willson design method to design the experiments, the operating ranges of variables are:  air velocity range from 0.408 to 0.566 m/s and designated as x1.  mixing time range from 1 to 5 minutes, and designated as x2.  particle size of trace component range from 0.4 to 1.09 mm and designated as x3.  concentration of trace component range from 5 to 25% by weight and designated as x4. materials sand with particle size of 0.74 mm was used, salt with the same size was used and if it was used as a trace component it’s particle size was 0.4, 0.57, 0.74, 0.915 and 1.09 mm and cast iron which was used always as a trace component in all sets and it’s particle size 0.4, 0.57, 0.74, 0.915 and 1.09 mm. each component was close-sieved to give a narrow size distribution. the physical properties of the material are tabulated in table 2. table 2 physical properties of the materials [12] physical properties sand salt cast iron real density, kg/m 3 2530 2100 7030 shape factor 0.6-0.861 0.63 0.578 surface properties non-cohesive free flowing same same besides magnetic abbas h. sulaymon and rasha habeb salman ijcpe vol.9 no.1 (march 2008) 3 equipment equipment consisting mainly of the following parts: a. fluidization system: 1. fluidization column: experiments were conducted in a 150 mm id q.v.f glass column, 900 mm in height and open at the top to the atmosphere. 2. air distributor plate: it is covered with wire screen to prevent particles leakage. the distributor was placed firmly between the cylindrical section and the conical section using two flanges equipped with gaskets. 3. air flow rate measurement: air is supplied by means of a compressor (type lmf) which is used as a fluidizing gas. air is fed to a copper coil then to a damping tank to minimize plus fluctuations in flow rate. the air was metered by means of three calibrated rot meters before entering the fluidizing bed system, which were regulated by means of a glob valve for each rot meter. the rot meters were calibrated using wet gas meter device. 4. the pressure drop across the material was measured by using a u-tube manometer filled with water drawing samples from the fluidized bed by means of a pipe made from taflon which is connected to the vacuum. fig 1 shows the schematic diagram of the experimental setup. fig. 1 schematic diagram of experimental setup b. spinning riffler sampler type (q-retsch) consisting of the following parts: 1. receiver (conical hopper) of dimensions 190 mm upper diameter, 300 mm height diameter, 27 mm outlet diameter and 40 mm outlet channel length. 2. vibratory feeder which is a rectangular channel of 200 mm length and 50 mm width (with side wedges of 20 mm height). variables vibration (range of vibration 0 to 100) was used to control flow rate of sample from the hopper. 3. spinning riffler divider: which is dividing and reducing dry granular material by golden rule method, consisting of small receiving hopper (cylindrical shape of 180cm 3 capacity), leading to a dividing channel to eight sample jars. constant speed of rotation of 100 rpm was used. a. glass beakers and funnels were used for dissolving the salt and filtering the sand. b. drying oven (funditor ltd. , london and wembley). c. sieves. d. test sieve shaker, (type endecott) with timer. e. balance meter with maximum weight 1500 g (type satorius), accuracy 2 orders. procedure the choice of using the materials was strongly based on the utilized of available and easy analyzable materials. a mixture of sand and salt could be separated by dissolving out the salt and drying sand .for a mixture of cast iron, salt and sand, a magnetic bar was utilized to easy separation of the components both for analysis of the samples and for removing all trace material from the bed. the total weight of the charged was 2500 g. the procedure in all experiments was basically the same. 1. weighted quantities of the particulate components (according to box-wilson design of experiments) were poured into the column carefully to obtain a horizontal interface between the components. 2. air at chosen flow rate was set for a desired time to ensure that mixing was achieved. after the desired time, the source of air flow rate was shut down and when the bed settled ten samples were taken from ten different positions axially and radically, which are position 1cm above the air distributor and spaced 2 cm axially between them and 1.5 cm radically. a. each sample was loaded to the spinning riffler sampler where it subdivided into eight jars. b. each jar was weighted. c. for a mixture of sand and salt: the salt was dissolved using water, the sand was filtered and dried. for a mixture of cast iron with sand and salt the cast iron in each jar was separated magnetically and the remaining components were re-weighted and the weight of cast iron was obtained by subtracted the weight of other components from the total weight. results and discussion the minimum fluidized velocity of each component was found by preliminary tests which were carried out to find the amount of air which are sufficient to fluidize the considered materials and it was found that: umf cast iron (0.408 m/s) > umfsand (0.29 m/s) > umf salt(0.283 m/s) statistical analysis estimation the coefficients of the proposed correlation using the experimental data which are fitted by nonlinear regression analysis statistica software, the coefficients of the second order polynomial are estimated silica gel rotamoters taflon rod fluidized bed water manometer sample collector vacuum supply damping tank coil air supply a quantitative analysis of the mixing of three solids different in density by an air fluidized bed ijcpe vol.9 no.1 (march 2008) 4 and the second order polynomial was predicated that reasonably correlates the mixing index in terms of controllable variables. for set (1) the following response function is obtained which correlates the four variables with mixing index: 43423241 3121 2 4 2 3 2 2 2 14321 8422.009.00692.04487.0 377.04817.097.7467.00291.0 441.8552.10399.10636.0352.76089.1 xxxxxxxx xxxxxxx xxxxxm    (5) for set (2) the following response function is obtained which correlates the four variables with mixing index: 43423241 3121 2 4 2 3 2 2 2 14321 706.00685.00391.0391.0 411.0447.0833.74379.00277.0 68.80967.19385.004559.05968.76.1 xxxxxxxx xxxxxxx xxxxxm    (6) the optimum conditions of the four variables that correspond to the maximum mixing index for each set of experiments are found they were: air velocity=0.526 m/s, mixing time=4 min, particle size of trace component=0.74mm and concentration of trace component=10 % by weight. maximum values of mixing index for set (1) was 0.9554 while for set (2) was 0.9298. according to table 1 the first set of experiments gives very good mixing and the second set of experiments gives good mixing. effect of studied variables on the mixing index the effect of each variable (air velocity, mixing time, particle size of trace component and concentration of trace component) on the mixing index is found by studying each variable separately from other variables by keeping them constant at their optimum values and this is represented in fig. 2 to 5. each figure represents the two sets of experiments. in fig. 2, the effect of air velocity on the mixing index is shown, it can be noticed that mixing index is increased with increasing air velocity until the air velocity reaches an optimum value at which the maximum mixing index is reached. after this value however the air velocity is increased, the mixing index is decreased. previous work has shown that mixing does not occur until a gas velocity is reached at which the bed is bubbling, and the lowest possible velocity at which this happens is the lower of the two fluidization velocities (uf). as the gas velocity increases further, so the rate of bubbling increases, and this leads to improve mixing [13]. the volume of gas passing through the system in the form of bubbles is approximately equal to the excess volumetric flow rate and as a bubble rose through the upper layer it took with it a wake composed of material from the lower layer, but it has already been mentioned that segregation is optimized by the presence of small bubbles in the bed by the use of small excess gas velocity [3]. u, m/s 0.40 0.42 0.44 0.46 0.48 0.50 0.52 0.54 0.56 0.58 m 0.80 0.82 0.84 0.86 0.88 0.90 0.92 0.94 0.96 0.98 set 1 set 2 fig. 2 effect of air velocity on mixing index mixing depends on the rate of bubbling but this does not necessarily increase with increasing gas flow-rate, so any further increasing in air velocity mixing index may be decreased [14]. fig. 3 shows the effect of mixing time on mixing index, it can be noticed that the behavior of mixing index with mixing time is the same as time, min 0 1 2 3 4 5 6 m 0.5 0.6 0.7 0.8 0.9 1.0 set 1 set 2 fig. 3 effect of mixing time on mixing index the behavior of mixing index with air velocity and this in agreement with fan model (sited in [15]), which states that mixing effect increases with increasing time but as mentioned previously the mixed state represents an intermediate state so that the segregation effect will appear as the mixing time increases. in fig. 4 the effect of particle size on mixing index is shown. particles size difference is by far the most important and most serious cause of segregation [3]. abbas h. sulaymon and rasha habeb salman ijcpe vol.9 no.1 (march 2008) 5 dp, mm 0.2 0.4 0.6 0.8 1.0 1.2 m 0.86 0.88 0.90 0.92 0.94 0.96 set 1 set 2 fig. 4 effect of particle size on mixing index according to ashton and valentin [7], the easy mixture was produced whenever there is no difference in particle sizes between the two components. therefore the segregation effect is found when there is a particle sizes difference. “non-easy” mixtures were produced whenever differences in specific gravity or particle sizes occurred between the two mixture components. the extent of segregation occurring was related to the magnitude of difference in specific gravity or particle sizes. fig. 5 shows the effect of concentration of trace component on mixing index. mixing index increases with increasing the concentration of trace component until it reaches an optimum value after it the demixing increases and mixing index decreases. the mixing of the particles is due to bulk solids circulation this circulation decreases with increasing density for mixture [14]. conc.,% 0.00 0.05 0.10 0.15 0.20 0.25 0.30 m 0.70 0.75 0.80 0.85 0.90 0.95 1.00 set 1 set 2 fig. 5 effect of concentration of trace component on mixing index fig. 6 shows the interaction effect between air velocity and time of mixing on mixing index while keeping the other two variables (particle size and concentration of trace component) constant at their optimum value. as mentioned before the mixing rate increases with increasing air velocity and time of mixing until the air velocity reaches it’s optimum value, then the rate of mixing will decrease and rate of demixing increase so as for the time of mixing when it continue in increasing the rate of mixing increasing too until the time of mixing reaches it’s optimum value then the segregation rate increases however mixing time increases. fig. 7 shows the interaction effects between air velocity and particle size of trace component on the mixing index. as mentioned before that according to ashton and valentin [7] the mixtures can be classified to easy mixtures (same particle sizes of the components) and non-easy mixtures (different particle sizes of the components). it’s now clear that when the particles are of different sizes and /or density, problems of segregation occur and according to harwood et al. [16] the freeflowing/free-flowing powder pairs had very tendency to segregation due to the difference in particle sizes between the components which were used. according to fan et al. [15] these differences in size and/or density on rate appears to follow the path of rising very rapidly initially, passing through a maximum, and diminishing to a point of equilibrium. fig. 8 shows the interaction effect of mixing time and concentration of trace component (salt or cast iron) on mixing index. this figure indicates that mixing index increases with increasing mixing time and with continuing in mixing process. it reaches an optimum value (where the maximum value of mixing index can be obtained) then the segregation effect will appear as mixing time increases and this behavior agrees with fan’s model. the interaction effect of concentration of trace component (salt or cast iron) in consideration it can be seen that mixing index increases with increasing concentration of trace component until the concentration reaches it’s optimum value which it was equal to 10 % by weight. fig. 9 shows the interaction effect of concentration of trace component and particle size of trace component on mixing index. as shown in fig. 9 mixing index increases with increasing concentration of trace component because the increasing of distribution of particles of trace component between the other component (sand or salt or sand-salt) particles (lacey [17]). according to poole et al. [18] high ratio of tracer blends are more easily randomized than low ratio ones, and after this optimum value with continuation of mixing process the vibration segregation effect will appear when the larger particles tend to rise to the surface [19]. therefore, the effect of different partied size on mixing index has a higher effect than the increasing of air velocity. a quantitative analysis of the mixing of three solids different in density by an air fluidized bed ijcpe vol.9 no.1 (march 2008) 6 time, min 0 1 2 3 4 5 6 m 0.5 0.6 0.7 0.8 0.9 1.0 u = 0.408 m/s u = 0.448 m/s u = 0.487 m/s u = 0.526 m/s u = 0.566 m/s set 1 time, min 0 1 2 3 4 5 6 m 0.5 0.6 0.7 0.8 0.9 1.0 u = 0.408 m/s u = 0.448 m/s u = 0.487 m/s u = 0.526 m/s u = 0.566 m/s set 2 fig. 6 interaction effect between air velocity and mixing time on mixing index u, m/s 0.40 0.42 0.44 0.46 0.48 0.50 0.52 0.54 0.56 0.58 m 0.70 0.75 0.80 0.85 0.90 0.95 1.00 dp = 0.40 mm dp = 0.57 mm dp = 0.74 mm dp = 0.915 mm dp = 1.09 mm set 1 u, m/s 0.40 0.42 0.44 0.46 0.48 0.50 0.52 0.54 0.56 0.58 m 0.70 0.75 0.80 0.85 0.90 0.95 1.00 dp = 0.40 mm dp = 0.57 mm dp = 0.74 mm dp = 0.915 mm dp = 1.09 mm set 2 fig. 7 interaction effect between air velocity and particle size on mixing index time, min 0 1 2 3 4 5 6 m 0.4 0.5 0.6 0.7 0.8 0.9 1.0 conc. = 5 % conc. = 10 % conc. = 15 % conc. = 20 % conc. = 25 % set 1 time, min 0 1 2 3 4 5 6 m 0.4 0.5 0.6 0.7 0.8 0.9 1.0 conc. = 5 % conc. = 10 % conc. = 15 % conc. = 20 % conc. = 25 % set 2 fig. 8 interaction effect of mixing time and concentration of trace component on mixing index abbas h. sulaymon and rasha habeb salman ijcpe vol.9 no.1 (march 2008) 7 conc., % 0.00 0.05 0.10 0.15 0.20 0.25 0.30 m 0.65 0.70 0.75 0.80 0.85 0.90 0.95 1.00 dp = 0.40 mm dp = 0.57 mm dp = 0.74 mm dp = 0.915 mm dp = 1.09 mm set 1 conc., % 0.00 0.05 0.10 0.15 0.20 0.25 0.30 m 0.65 0.70 0.75 0.80 0.85 0.90 0.95 1.00 dp = 0.40 mm dp = 0.57 mm dp = 0.74 mm dp = 0.915 mm dp = 1.09 mm set 2 fig. 9 interaction effect of concentration and particles size of trace component on mixing index u, m/s 0.40 0.42 0.44 0.46 0.48 0.50 0.52 0.54 0.56 0.58 m 0.6 0.7 0.8 0.9 1.0 conc. = 5 % conc. = 10 % conc. = 15 % conc. = 20 % conc. = 25 % set 1 u, m/s 0.40 0.42 0.44 0.46 0.48 0.50 0.52 0.54 0.56 0.58 m 0.6 0.7 0.8 0.9 1.0 conc. = 5 % conc. = 10 % conc. = 15 % conc. = 20 % conc. = 25 % set 2 fig. 10 interaction effect between air velocity and concentration of trace component on mixing index time, min 0 1 2 3 4 5 6 m 0.5 0.6 0.7 0.8 0.9 1.0 dp = 0.40 mm dp = 0.57 mm dp = 0.74 mm dp = 0.915 mm dp = 1.09 mm set 1 time, min 0 1 2 3 4 5 6 m 0.5 0.6 0.7 0.8 0.9 1.0 dp = 0.40 mm dp = 0.57 mm dp = 0.74 mm dp = 0.915 mm dp = 1.09 mm set 2 fig. 11 interaction effect of mixing time and particle size of trace component on mixing index fig. 10 shows the interaction effect of air velocity and concentration of trace component (cast iron) on the mixing index. it can be seen that mixing index increases with increasing air velocity in the same manner as that shown in fig. 6, and with increasing concentration of trace component until they reach their optimum values. fig. 11 shows the interaction effect of mixing time and particle sizes of trace component on mixing index. it can be noticed that mixing index increases with increasing a quantitative analysis of the mixing of three solids different in density by an air fluidized bed ijcpe vol.9 no.1 (march 2008) 8 mixing time in the same manner as that shown in figure 3, and the particle sizes of trace component (salt or cast iron) which will give the maximum value of mixing index (higher performance of mixing) is equal to 0.74 mm. examining the data it can be noticed that the presence of a modest sizes difference will tend to accelerate the rate of mixing in comparison with the case of identical particles. the effect of segregation increase and mixing index decrease, and the behavior of particle size of trace component agree with ashton and valentin [7]. conclusions 1. particle size and density differences are the main cause of segregation which has an appreciable effect in the range used. 2. mixing index increases with increasing the air velocity, time of mixing and concentration of trace component until they reach their optimum values. 3. mixing index depends on the magnitude of different particle size so when there is no particle size difference between the main component and the trace component, best mixing will be achieved. 4. set (1) gives higher mixing index and better performance of mixing than set (2). nomenclature dp particle size, mm m mixing index n number of samples t mixing time, min u superficial gas velocity (measured on an empty bed), m/s δ standard deviation δo standard deviation of totally segregated mixture references 1. vaizoglu, o., “assessment of the degree of mix of powder characterization of dispersive and distributive mixing in a single screw extruder”, tr. j. physics, 23, 94-104 (1999). 2. alemaskin, k., zloczower, i. m. and kaufman, m., “simulation characterization of dispersive and distributive mixing in a single screw extruder”, int. polym. process, department of macromolecular science, case western reserve university, cleveland, ohio (2002). 3. harnby, n., edwards, m. f. and nienow, a. w., “mixing in the process industries”, butter worths, london, (1985). 4. hartholt, g. p., hoffman, a. c. and janssen, l. p., “visual observation of individual particle behavior in gas and liquid fluidized beds”, powder technology, 88, 341-345 (1996). 5. naimer, n. s., chiba, t. and nienow, a. w., “parameter simulation for a solid mixing/segregation model for gas fluidized beds”, chem. eng. sci., 37 (7), 1047-1057 (1982). 6. liyod, p. j. and yeung, p. c., “mixing of powders”, chem. process eng., 57 (1967). 7. ashton, m. d. and valentin, f. h. h., “the mixing of powders and particles in industrial mixers”, trans. inst. chem. engrs., 44, t166-t188 (1966). 8. fan, l. t. and wang, r. h., “on mixing indecies”, powder technology, 11, 27-32 (1975). 9. rose, h. e., “a suggested equation relating to the mixing of powders”, trans. inst. chem. engrs., 37, 47 (1959). 10. boss, j. and poland, w. m., “evaluation of the homogeneity degree of a mixture”, bulk solid handling, 6 (6), 1207 (1986). 11. sahoo, a. and roy, g. k., “mixing characteristic of homogeneous binary mixture of regular particles in a gas-solid fluidized bed”, powder technology, (2005). 12. perry, j. h., “chemical enginee’s handbook”, 5 th edition, mcgraw hill, new york, (1984). 13. nienow, a. w., rowe, p., n. and cheung, l. y. l., “a quantitative analysis of the mixing of twp segregating powders of different density in a gasfluidized bed”, powder technology, 20, 89-97 (1978). 14. scarlett, b., “mixing”, chem. process eng., 612 (1964). 15. fan, l. t., gleves-arocha, h. h., walawender, w. p. and lai, f. s., “a mechanistic kinetic model of the rate of mixing segregating solid particles”, powder technology, 12, 139-156 (1975). 16. harwood, c. f., walanski, k., luebacke, e. and swanstrom, c., “the performance of continuous mixes for dry powders”, powder technology, 11, 289296 (1975). 17. lacey, p. n., “the mixing of solid particles”, trans. inst. chem. engrs. 21, 53 (1943). 18. poole, k. p., taylor, r. f. and wall, g. p., “mixing powders to fine scale homogeneity: studies of continuous mixing”, trans. inst. chem. engrs., 43, t261 (1965). 19. harnby, n., “a comparison of the performance of industrial solids mixers using segregation materials”, powder technology, 1, 94-102 (1967). available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.20 no.1 (march 2019) 9 – 14 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: forqan m. hameed, email: forqanmohammed1@gmail.com, khalid m. mousa, email: khalidmousa15@gmail.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. study on kinetic and optimization of continuous advanced oxidative decolorization of brilliant reactive red dye forqan m. hameed and khalid m. mousa chemical engineering department, al-nahrain university, iraq abstract the azo dye brilliant reactive red k-2bp (λmax = 534 nm) is widely used for coloring textiles because of its low-cost and tolerance fastness properties. wastewaters treatment that contains the dye by conventional ways is usually inadequate due to its resistance to biological and chemical degradation. during this study, the continuous reactor of an advanced oxidation method supported the use of h2o2/sunlight, h2o2/uv, h2o2/tio2/sunlight, and h2o2/tio2/uv for decolorization of brilliant reactive red dye from the effluent. the existence of an optimum ph, h2o2 concentration, tio2 concentration, and dye concentration was taken from the batch reactor experiments. the best conditions were ph=3, h2o2 dosage = 500 ppm, tio2=100ppm and dye concentration=15 ppm .under the most effective conditions, complete removal of the dye solution was achieved with different flow rates (10, 30, 60) ml/min. at flow rate of 10 ml/min, the percentage of decolorization were (80.47%, 84.65%, 89.42%, 77.5%) and at 60 ml/min (65.19%, 68.26%, 70.01%, 56.8%) for h2o2/sunlight, h2o2/uv, h2o2/tio2/sunlight and h2o2/tio2/uv respectively. results of degradation information showed that the decolorization method was pseudo-first-order kinetics. keywords: reactive red, photodegradation, advanced oxidation processes (aop), wastewater, sunlight received on 08/10/8102, accepted on 17/12/8102, published on 30/03/8109 https://doi.org/10.31699/ijcpe.2019.1.2 1introduction wastewater produced from the textile industry typically contains high concentrations of organic, inorganic materials, high cod, high ph and strong apparent color ‎[1]. dyes from coloring processes are the primary supply of color textile wastewater and it may cause serious environmental issues ‎[2]. there are different types of treatment such as physicalchemical treatment included [coagulation-flocculation, adsorption on activated carbon and reverse osmosis] and biological treatment are used for removal toxic substance from wastewater. biological treatment isn't effective enough to remove dyes from effluent while physicalchemical treatment is not strong enough to decolor the dye so it generated a sludge and adsorbent regeneration are the principal weaknesses of those methods ‎[3]. advanced oxidation processes (aops), that are considered a chemical treatment of wastewater and it is the most effective process for the removal of the organic pollutants ‎[4]. aops are based on the generation of hydroxyl radical (oh*) that are capable of degrading the organic pollutants to carbon dioxide, water, and inorganic materials ‎[5]. various of aops include chlorination, ozonation, fenton, photo-fenton, photo-catalytic and wet-air oxidation ‎[6]. h2o2/uv process is one of the advanced oxidation technique, hydrogen peroxide is photolysis to generate the oh* responsible for oxidation. hydroxyl radicals are attacked the organic molecules causing their destruction and mineralization. also, another method is the photocatalyst with titanium dioxide that is a wide band gap semiconductor and it is used nearuv light of wavelength shorter than 380 nm or sunlight. tio2 particles can form a paired electron (e-) and hole (h+), in the conduction band and valence band when it was the absorption of the ultraviolet radiation. the positive hole is seemingly ready to oxidize a water molecule to hydroxyl radical. the hydroxyl radical, in turn, is a powerful oxidant ‎[7]‎[8]. the processes of h2o2/uv, h2o2/tio2/uv treatment depends on many conditions that have an effect on the degradation of organic pollutants. the conditions include the type and concentration of the organic materials, hydrogen peroxide concentration, tio2 amount, light source, ph, temperature, flow rate and reaction time ‎[9]. the most important parameter is the dosage of h2o2 when its increased the formation of hydroxyl radical will be increased, therefore increasing the decolorization rate to optimal value then the h2o2 react with oh* and decreased in the decolorization rate ‎[10]. ph plays a major role in the photocatalytic process. the decolorization rate of azo dyes will increase with a decrease in the ph ‎[11]. https://doi.org/10.31699/ijcpe.2019.1.2 f. m. hameed and k. m. mousa / iraqi journal of chemical and petroleum engineering 20,1 (2019) 9 14 01 the photooxidation activity was the maximum decolorization rate under ph<6 and it was found to decrease when ph>6, it undergoes decomposition generating dioxygen and water lead to the less formation of oh* ‎[12] in the photocatalyst, the catalyst has a control on the process, when it's increased in the quantity of it will increase in the number of active sites, that successively will cause increase the concentration of hydroxyl radical and superoxide radicals. also when the catalyst amount will increase higher than the optimum value, the rate of decolorization decreases because of the interception of the light by the suspension ‎[13]. there are several studies in batch advanced oxidation, while limited studies in continuous processes conducted to remove the dye using solar energy. huang et al. ‎[14] studied the parameter of adding the amount of hydrogen peroxide to remove the methyl orange from solution. the removal efficiency was increased with increase in h2o2 concentration. zhiyong et al. ‎[15] studied the addition of hydrogen peroxide with titanium dioxide degussa p25 (0.5g/l) catalyst (1mm) to remove methyl orange solution under sunlight irradiation. senthil kumar et al. ‎[16] reported that the increase in the concentration of oh* will cause the reduction of the hydrogen peroxide ‎[17] ali ‎[18] studied the continuous photo-catalytic reactor using tio2/uv process to treat wastewater solution, it showed that the rate of degradation of organic pollutants decreased with increase in the flow rate and increased with increasing the number of the uv lamp. the aim of this study is to treat the wastewater effluent from the textile factory in the north of baghdad from the azo brilliant reactive red k-2bp by a continuous advanced oxidation process using (h2o2/uv, h2o2/sunlight, h2o2/tio2/uv, and h2o2/tio2/sunlight) and compare the results. 2experimental the chemicals used in this study were brilliant reactive red that is employed in textile as a waste. h2o2 (50% w/w) was obtained from merck. tio2 (p-25, 80t% anatase, 20% rutile with particle size 30±5 nm) was used. h2so4 and naoh were used to modify the ph of the solutions. the continuous reactor composed of 2 layers of a glass reactor (80 x 30 x 1) cm. the depth between them is 4 mm. the upper layer glass was 6 mm thickness and the lower layer is a reflective mirror. the solution passes between the two layers. two liters of effluent introduced to the unit at optimum conditions, ph= 3, dye concentration= 15 ppm, h2o2= 500 ppm, and tio2 =100 ppm. these optimum conditions were taken from a prestudy of batch experiments. the tests were conducted throughout the months of may and june with the temperature stable up to 35 ± 3 c°. the radiation intensity was measured employing a device sort (the daystar meter) that reads 494-565 watt/m 2 at 9 am, 680-705 watt/m 2 at 10 am and 775-805 watt/m 2 at 12 pm. the processes (h2o2/uv, h2o2/sunlight, h2o2/tio2/uv, and h2o2/tio2/sunlight) for decolorization of reactive red dye from simulated solution were used. the concentration of red dye is measured by uv-spectrophotometer at 534nm maximum of absorption. fig. 1 and fig. 2 show the sketch and photograph of a continuous reactor. the removal efficiency (%) was calculated using equation 1: removal efficiency (%) = (co – c)/ co x100 (1) where, co = the initial concentration of contaminants (dyes) in the samples wastewater (mg/l). c = the concentration (mg/l) after treatment. fig. 1. sketch of a continuous system. (1) container tank (dye solution), (2) water pump, (3) valve, (4) flow meter, (5) chamber containing the photooxidation reactor, (6) uv lamp, (7) baffle (8) container tank (produced water treated). fig. 2. photograph of continuous reactor f. m. hameed and k. m. mousa / iraqi journal of chemical and petroleum engineering 20,1 (2019) 9 14 00 3kinetic analysis the wastewater treatment of the textile that contains a dye is a complicated method involving several reactions. therefore, approximate kinetics can be assumed for the removal of the dye in the effluents. the most color removal curves obey to the several investigators that are first or second order kinetics. the major color removal curves lead to the first order kinetic model ‎[19]. the rate of kinetic for the first order reaction can be calculated from equation 2: (2) where, dc/dt = the rate of change of dye concentration with a change of reaction time. k = the rate constant min -1 and c is the concentration of dye at time t. then the integration of equation (2) between t = 0 and t = t gives; [ ] [ ] (3) where: c0 = initial dye concentration at time t = 0. c = dye concentration at time t. k = first order rate constant min -1 . t = reaction time in minutes. 4energy requirement the advanced oxidation treatment is directly affected by operation cost. to compare of reaction efficiencies that used parameter known as ee/o (electrical energy required to remove a pollutant by one order in one m 3 of water or wastewater). ee/o calculated the electrical efficiency of an advanced oxidation process and allows for the comparison of various aop methods. it is very required not only for several of aops also for economic analysis and comparison with conventional treatment. ee/o values are shown in equation 4 ‎[20] ‎[21]. ee/o = ( ) ( ) ( ) ( ) (4) where: p = the power input to the system such as uvlamp, generator of ozone, magnetic stirrer and water pump in kw. t = the reaction time in min. v = the volume of the wastewater in l. c0 = the initial concentration of pollutant water at t = 0. c = the final concentration of pollutant water after treatment. 5results and discussion the decolorization rate of dye depends on the optimum h2o2 concentration to generate the hydroxyl radicals that destroy the organic polluted ‎[22]. the catalyst is also affected by advanced oxidation processes ‎[23]. in the presence of photocatalyst (tio2), h2o2 or only h2o2, the ph is an optimizing parameter at acidic that got accelerated the rate of decolorization. on the other hand, an increase in irradiation time led to greater decolorization rate‎[24]. according to a previous studies, a pre-study was conducted to find the optimum conditions of h2o2 concentration,tio2 amount, ph and dye concentration and it was found that [h2o2] = 500ppm, [tio2]= 100ppm, ph= 3 and dye concentration= 15ppm. fig. 3, fig. 4, fig. 5 and fig. 6 show the results of a continuous process for the four processes (h2o2/uv, h2o2/sunlight, h2o2/tio2/uv, and h2o2/tio2/sunlight) respectively at the optimum conditions. the flow rate to the reactor was adjusted according to the detention time dt=v/q (volume/flow rate) ‎[25]. when the flow rate increases (10, 30 and 60) ml/min the detention time (min) will be (150, 50 and 25) respectively. at each detention time, the same volume of wastewater had been treated but with different removal efficiencies. the treated volume is 1500 ml. the removal efficiency for four processes was (84.65%, 80.47%, 77.51%, and 89.42%) at the flow rate 10ml/min and (68.26%, 65.19%, 56.89%, 70.22%) at 60ml/min respectively. increasing the flow rate the uv lamp or sunlight will be submerged in shorter time, therefore, decreases the amount of provided power for h2o2 to generate more hydroxyl radical. fig. 3. effect of flow rate on the decolorization of red dye: ph= 3, [h2o2] = 500mg/l, [dye] = 15mg/l, and 2 uv lamp fig. 4. effect of flow rate on the decolorization of red dye: ph= 3, [h2o2] = 500mg/l, [dye] = 15mg/l, and sunlight 0 40 80 120 0 20 40 60 80 r e m o va l e ff ic ie n cy % flow rate , ml/min 0 40 80 120 0 20 40 60 80 r e m o va l e ff ic ie n cy % flow rate , ml/min f. m. hameed and k. m. mousa / iraqi journal of chemical and petroleum engineering 20,1 (2019) 9 14 01 fig. 5. effect of flow rate on the decolorization of red dye: ph= 3, [h2o2] = 500mg/l, [dye] = 15mg/l, [tio2] = 100mg/l and 2 uv lamp fig. 6. effect of flow rate on the decolorization of red dye: ph= 3, [h2o2] = 500mg/l, [dye] = 15mg/l, [tio2] = 100mg/l and sunlight 6kinetics study the various values of reaction rate constant k (min -1 ) calculated from eq. 3 are shown in table 1 for different advanced oxidation processes. for different (h2o2/sunlight, h2o2/uv, h2o2/tio2/ uv, and h2o2/tio2/ sunlight) methods the k values were 0.0041/min, 0.0053/min, 0.0053/min and 0.0080/min respectively. the coefficient of correlation is presented by r2 and explains the fitting extent of the equation, experimental information. the values of those r 2 are nearly closed or higher than 0.9 in all cases. it is apparent that h2o2/uv is better than h2o2/sunlight process. this means that the uv lamp is much faster than sunlight for photolysis of hydrogen peroxide. in the photocatalyst the addition of h2o2 ensures many formations of oh* radicals that can be destroyed organic pollutants, the results showed that h2o2/tio2/sunlight is better than h2o2/tio2/uv because sunlight contains a wavelength around 380nm that catalyst tio2 can be absorption this agrees with ‎[26]. in the four advanced oxidation experiments, the kinetics model of red dye is represented as first-order reaction kinetics. table 1. the first-order reaction kinetics model for different advanced oxidation processes methods k(min -1 ) r 2 h2o2/uv 0.0053 0.9174 h2o2/sunlight 0.0041 0.8635 h2o2/tio2/uv 0.0053 0.9992 h2o2/tio2/sunlight 0.0080 0.9863 7calculation of electrical energy requirements the advanced oxidation processes are required to spend energy for operating the equipment. in this study consist of four processes (h2o2/sunlight, h2o2/uv, h2o2/tio2/ uv, and h2o2/tio2/sunlight) which is used a variable source of power like uv lamp and water pump. ee/o is the electrical energy per order of water or polluted water removal. in the other hand, it means a powerful parameter and a measure of the degradation rates obtained in a very constant volume of wastewater as a function of the applied specific energy ‎[20] ‎[27]. table 2 shows the comparison of energy requirements by various methods for the decolorization rate of brilliant reactive red dye at different flow rate dye. the energy required can be calculated from eq. 4. the results are apparent that the h2o2/uv and h2o2/tio2/sunlight processes most effective option of energy required and decolorization of dye. energy consumption of the advanced oxidation treatment increase with an increased in initial dye concentrations, flow rate and also with an increase in the applied dose ‎[27]. table 2. comparison of the energy required by the different processes for the decolorization rate of brilliant reactive red dye at a different flow rate reaction conditions dye conc.=15ppm, h2o2=500ppm, tio2=100ppm and ph=3 flow rate 10 (ml/min) 30 (ml/min) 60 (ml/min) methods of aops declorization rate % ee/o (kwh/m 3 ) declorization rate % ee/o (kwh/m 3 ) declorization rate % ee/o (kwh/m 3 ) h2o2/uv 84.65 12.62 77.34 15.94 68.26 20.61 h2o2/sunlight 80.47 14.48 74.50 17.31 65.19 22.42 h2o2/tio2/uv 77.51 15.85 61.45 24.82 56.89 28.12 h2o2/tio2/sunlight 89.42 10.53 78.39 15.44 70.22 19.53 0 40 80 120 0 20 40 60 80 r e m o va l e ff ic ie n cy % flow rate , ml/min 0 40 80 120 0 20 40 60 80 r e m o va l e ff ic e n cy % flow rate , ml/min f. m. hameed and k. m. mousa / iraqi journal of chemical and petroleum engineering 20,1 (2019) 9 14 02 8conclusions brilliant reactive red dye can be removed in all of the advanced continuous methods of oxidation that is used in this study, at a flow rate range from (10-60) ml/min and reaction time ranging from (25 – 150) min. however, the increase in the flow rate led to a decrease in the decolorization rate. the higher decolorization was required longer reaction time to generate hydroxyl radical that can destroy the organic substance. the results show that the h2o2/ uv and h2o2/tio2/uv processes can be efficiently used for removal of textile wastewater because h2o2 absorb the light >245nm and tio2 absorb the light > 365nm. the maximum decolorization rate of dye may be achieved at acidic media (ph =3), a moderate concentration of h2o2, 150 min of uv irradiation and low flow rate by 10ml/min. the results indicated that sunlight is a suitable energy supply used in the photooxidation to remove organic substance due to its low cost and free availability. references [1] y. m. slokar, j. zupan, and a. m. le marechal, “the use of artificial neural network (ann) for modeling of the h2o2/uv decoloration process: part i,” dye. pigment., vol. 42, no. 2, pp. 123–135, 1999. [2] i. koyuncu, “reactive dye removal in dye/salt mixtures by nanofiltration membranes containing vinylsulphone dyes: effects of feed concentration and cross flow velocity,” desalination, vol. 143, no. 3, pp. 243–253, 2002. [3] y. m. slokar and a. m. le marechal, “methods of decoloration of textile wastewaters,” dye. pigment., vol. 37, no. 4, pp. 335–356, 1998. [4] s. k. sharma, h. bhunia, and p. k. bajpai, “photocatalytic decolorization kinetics and adsorption isotherms of a mixture of two anionic azo dyes: reactive red 120 and reactive black 5,” desalin. water treat., vol. 44, no. 1–3, pp. 261–268, 2012. [5] a. vogelpohl and s.-m. kim, “advanced oxidation processes (aops) in wastewater treatment,” j. ind. eng. chem., vol. 10, no. 1, pp. 33–40, 2004. [6] t. robinson, g. mcmullan, r. marchant, and p. nigam, “remediation of dyes in textile effluent: a critical review on current treatment technologies with a proposed alternative,” bioresour. technol., vol. 77, no. 3, pp. 247–255, 2001. [7] f. zhang, j. zhao, t. shen, h. hidaka, e. pelizzetti, and n. serpone, “tio2-assisted photodegradation of dye pollutants ii. adsorption and degradation kinetics of eosin in tio2 dispersions under visible light irradiation,” appl. catal. b environ., vol. 15, no. 1–2, pp. 147–156, 1998. [8] y. yang and l. xu, “reusing hydrolyzed reactive dyebath for nylon and wool dyeing,” am. dyest. report., vol. 85, no. 3, pp. 27–34, 1996. [9] h.-y. shu and c.-r. huang, “ultraviolet enhanced oxidation for color removal of azo dye wastewater,” am. dyest. report., vol. 84, no. 8, pp. 30–35, 1995. [10] d. p. mohapatra, s. k. brar, r. d. tyagi, p. picard, and r. y. surampalli, “analysis and advanced oxidation treatment of a persistent pharmaceutical compound in wastewater and wastewater sludgecarbamazepine,” sci. total environ., vol. 470, pp. 58– 75, 2014. [11] i. k. konstantinou and t. a. albanis, “tio2assisted photocatalytic degradation of azo dyes in aqueous solution: kinetic and mechanistic investigations: a review,” appl. catal. b environ., vol. 49, no. 1, pp. 1–14, 2004. [12] m. stylidi, d. i. kondarides, and x. e. verykios, “pathways of solar light-induced photocatalytic degradation of azo dyes in aqueous tio2 suspensions,” appl. catal. b environ., vol. 40, no. 4, pp. 271–286, 2003. [13] s. chakrabarti and b. k. dutta, “photocatalytic degradation of model textile dyes in wastewater using zno as semiconductor catalyst,” j. hazard. mater., vol. 112, no. 3, pp. 269–278, 2004. [14] m. huang, c. xu, z. wu, y. huang, j. lin, and j. wu, “photocatalytic discolorization of methyl orange solution by pt modified tio2 loaded on natural zeolite,” dye. pigment., vol. 77, no. 2, pp. 327–334, 2008. [15] y. zhiyong et al., “photocatalytic discoloration of methyl orange on innovative parylene–tio2 flexible thin films under simulated sunlight,” appl. catal. b environ., vol. 79, no. 1, pp. 63–71, 2008. [16] s. senthilkumaar, k. porkodi, and r. vidyalakshmi, “photodegradation of a textile dye catalyzed by sol–gel derived nanocrystalline tio2 via ultrasonic irradiation,” j. photochem. photobiol. a chem., vol. 170, no. 3, pp. 225–232, 2005. [17] w. khan, i. najeeb, and s. ishtiaque, “photocatalytic degradation of a real textile wastewater using titanium dioxide, zinc oxide and hydrogen peroxide,” int j eng sci, vol. 5, no. 7, pp. 61–70, 2016. [18] ali abd al hassan, 2017, “treatment of produced water by advanced oxidation processes”, m.sc., thesis, al-nahrain university college of engineering [19] u. bali, e. çatalkaya, and f. şengül, “photodegradation of reactive black 5, direct red 28 and direct yellow 12 using uv, uv/h2o2 and uv/h2o2/fe2+: a comparative study,” j. hazard. mater., vol. 114, no. 1–3, pp. 159–166, 2004. [20] a. yasar, n. ahmad, and a. a. a. khan, “energy requirement of ultraviolet and aops for the post‐treatment of treated combined industrial effluent,” color. technol., vol. 122, no. 4, pp. 201– 206, 2006. [21] n. azbar, t. yonar, and k. kestioglu, “comparison of various advanced oxidation processes and chemical treatment methods for cod and color removal from a polyester and acetate fiber dyeing effluent,” chemosphere, vol. 55, no. 1, pp. 35–43, 2004. https://www.sciencedirect.com/science/article/abs/pii/s0143720899000224 https://www.sciencedirect.com/science/article/abs/pii/s0143720899000224 https://www.sciencedirect.com/science/article/abs/pii/s0143720899000224 https://www.sciencedirect.com/science/article/abs/pii/s0143720899000224 https://www.sciencedirect.com/science/article/pii/s0011916402002631 https://www.sciencedirect.com/science/article/pii/s0011916402002631 https://www.sciencedirect.com/science/article/pii/s0011916402002631 https://www.sciencedirect.com/science/article/pii/s0011916402002631 https://www.sciencedirect.com/science/article/pii/s0011916402002631 https://www.sciencedirect.com/science/article/abs/pii/s0143720897000752 https://www.sciencedirect.com/science/article/abs/pii/s0143720897000752 https://www.sciencedirect.com/science/article/abs/pii/s0143720897000752 https://www.tandfonline.com/doi/abs/10.1080/19443994.2012.691751 https://www.tandfonline.com/doi/abs/10.1080/19443994.2012.691751 https://www.tandfonline.com/doi/abs/10.1080/19443994.2012.691751 https://www.tandfonline.com/doi/abs/10.1080/19443994.2012.691751 https://www.tandfonline.com/doi/abs/10.1080/19443994.2012.691751 https://www.cheric.org/research/tech/periodicals/view.php?seq=441255 https://www.cheric.org/research/tech/periodicals/view.php?seq=441255 https://www.cheric.org/research/tech/periodicals/view.php?seq=441255 https://www.sciencedirect.com/science/article/pii/s0960852400000808 https://www.sciencedirect.com/science/article/pii/s0960852400000808 https://www.sciencedirect.com/science/article/pii/s0960852400000808 https://www.sciencedirect.com/science/article/pii/s0960852400000808 https://www.sciencedirect.com/science/article/pii/s0960852400000808 https://www.sciencedirect.com/science/article/pii/s092633739700043x https://www.sciencedirect.com/science/article/pii/s092633739700043x https://www.sciencedirect.com/science/article/pii/s092633739700043x https://www.sciencedirect.com/science/article/pii/s092633739700043x https://www.sciencedirect.com/science/article/pii/s092633739700043x https://www.sciencedirect.com/science/article/pii/s092633739700043x https://p2infohouse.org/ref/07/06635.pdf https://p2infohouse.org/ref/07/06635.pdf https://p2infohouse.org/ref/07/06635.pdf https://www.researchgate.net/publication/294803987_ultraviolet_enhanced_oxidation_for_color_removal_of_azo_dye_wastewater https://www.researchgate.net/publication/294803987_ultraviolet_enhanced_oxidation_for_color_removal_of_azo_dye_wastewater https://www.researchgate.net/publication/294803987_ultraviolet_enhanced_oxidation_for_color_removal_of_azo_dye_wastewater https://www.sciencedirect.com/science/article/pii/s0048969713010723 https://www.sciencedirect.com/science/article/pii/s0048969713010723 https://www.sciencedirect.com/science/article/pii/s0048969713010723 https://www.sciencedirect.com/science/article/pii/s0048969713010723 https://www.sciencedirect.com/science/article/pii/s0048969713010723 https://www.sciencedirect.com/science/article/pii/s0048969713010723 https://www.sciencedirect.com/science/article/pii/s0926337303005411 https://www.sciencedirect.com/science/article/pii/s0926337303005411 https://www.sciencedirect.com/science/article/pii/s0926337303005411 https://www.sciencedirect.com/science/article/pii/s0926337303005411 https://www.sciencedirect.com/science/article/pii/s0926337303005411 https://www.sciencedirect.com/science/article/pii/s0926337302001637 https://www.sciencedirect.com/science/article/pii/s0926337302001637 https://www.sciencedirect.com/science/article/pii/s0926337302001637 https://www.sciencedirect.com/science/article/pii/s0926337302001637 https://www.sciencedirect.com/science/article/pii/s0926337302001637 https://www.sciencedirect.com/science/article/pii/s0304389404002584 https://www.sciencedirect.com/science/article/pii/s0304389404002584 https://www.sciencedirect.com/science/article/pii/s0304389404002584 https://www.sciencedirect.com/science/article/pii/s0304389404002584 https://www.sciencedirect.com/science/article/abs/pii/s0143720807001283 https://www.sciencedirect.com/science/article/abs/pii/s0143720807001283 https://www.sciencedirect.com/science/article/abs/pii/s0143720807001283 https://www.sciencedirect.com/science/article/abs/pii/s0143720807001283 https://www.sciencedirect.com/science/article/abs/pii/s0143720807001283 https://www.sciencedirect.com/science/article/pii/s092633730700327x https://www.sciencedirect.com/science/article/pii/s092633730700327x https://www.sciencedirect.com/science/article/pii/s092633730700327x https://www.sciencedirect.com/science/article/pii/s092633730700327x https://www.sciencedirect.com/science/article/abs/pii/s1010603004003429 https://www.sciencedirect.com/science/article/abs/pii/s1010603004003429 https://www.sciencedirect.com/science/article/abs/pii/s1010603004003429 https://www.sciencedirect.com/science/article/abs/pii/s1010603004003429 https://www.sciencedirect.com/science/article/abs/pii/s1010603004003429 http://www.theijes.com/papers/v5-i7/i050701061070.pdf http://www.theijes.com/papers/v5-i7/i050701061070.pdf http://www.theijes.com/papers/v5-i7/i050701061070.pdf http://www.theijes.com/papers/v5-i7/i050701061070.pdf http://www.theijes.com/papers/v5-i7/i050701061070.pdf https://www.sciencedirect.com/science/article/pii/s0304389404004224 https://www.sciencedirect.com/science/article/pii/s0304389404004224 https://www.sciencedirect.com/science/article/pii/s0304389404004224 https://www.sciencedirect.com/science/article/pii/s0304389404004224 https://www.sciencedirect.com/science/article/pii/s0304389404004224 https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1478-4408.2006.00028.x https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1478-4408.2006.00028.x https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1478-4408.2006.00028.x https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1478-4408.2006.00028.x https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1478-4408.2006.00028.x https://www.sciencedirect.com/science/article/pii/s0045653503010609 https://www.sciencedirect.com/science/article/pii/s0045653503010609 https://www.sciencedirect.com/science/article/pii/s0045653503010609 https://www.sciencedirect.com/science/article/pii/s0045653503010609 https://www.sciencedirect.com/science/article/pii/s0045653503010609 https://www.sciencedirect.com/science/article/pii/s0045653503010609 f. m. hameed and k. m. mousa / iraqi journal of chemical and petroleum engineering 20,1 (2019) 9 14 03 [22] c. m. so, m. y. cheng, j. c. yu, and p. k. wong, “degradation of azo dye procion red mx-5b by photocatalytic oxidation,” chemosphere, vol. 46, no. 6, pp. 905–912, 2002. [23] n. m. mahmoodi, m. arami, n. y. limaee, k. gharanjig, and f. d. ardejani, “decolorization and mineralization of textile dyes at solution bulk by heterogeneous nanophotocatalysis using immobilized nanoparticles of titanium dioxide,” colloids surfaces a physicochem. eng. asp., vol. 290, no. 1–3, pp. 125– 131, 2006. [24] i. ahmad bhatti and s. irshad, “uv radiations assisted advanced oxidation approach for the degradation of reactive azo dye, using tio2 photocatalyst.,” j. chem. soc. pakistan, vol. 39, no. 5, 2017. [25] j. c. crittenden, r. r. trussell, d. w. hand, k. j. howe, and g. tchobanoglous, mwh’s water treatment: principles and design. john wiley & sons, 2012. [26] i. a. alaton and i. a. balcioglu, “photochemical and heterogeneous photocatalytic degradation of waste vinylsulphone dyes: a case study with hydrolyzed reactive black 5,” j. photochem. photobiol. a chem., vol. 141, no. 2–3, pp. 247–254, 2001. [27] j. r. bolton, k. g. bircher, w. tumas, and c. a. tolman, “figures-of-merit for the technical development and application of advanced oxidation processes,” j. adv. oxid. technol., vol. 1, no. 1, pp. 13–17, 1996. دراسة افضل ظروف باستخدام مفاعل مستمر لعممية االكسدة المتقدمة إلزالة الصبغة الحمراء التفاعمية الخالصة نانومتر عمى نطاق واسع لصباغة 534تفاعمية ذات المون االحمر والطول الموجي صبغة azo تستخدم المنسوجات بسبب فعاليتها من حيث التكمفة وخصائص ثبات ممتازة. وكثيرًا ما تكون معالجة مياه الصرف تدهور البيولوجي والكيميائي. الصحي المحتوية عمى هذه الصبغة بالطرق التقميدية غير كافية بسبب مقاومتها لم ,h2o2/sunlight) ) في هذه الدراسة يتم استخدام مفاعل مستمر لمعممية أكسدة متقدمة تقوم عمى استخدام h2o2/uv, h2o2/tio2/sunlight, h2o2/tio2/uv الزالة الصبغة الحمراء.وتم أخذ افضل الظروف من ثنائي اوكسيد التيتانيوم وتركيز الصبغة من الهيدروجين، تركيزحيث االس لمهيدروجيني ، تركيز بيروكسيد h2o2 =500، 3. وكانت أفضل ظروف األس الهيدروجيني = batch reactor)تجارب المفاعالت الدفعة ) مل . تحت أفضل الظروف تمت إزالة المون \ممغ15مل و تركيز الصبغ = \ممغ tio2 = 100 مل, \ممغ مل / 10( مل / دقيقة. في معدل تدفق 60، 30، 10صبغة مع معدل تدفق مختمف )لممحمول الحاوي عمى ال مل / دقيقة 60٪( وبمعدل 77.5٪، 89.42٪، 84.65٪، 80.47دقيقة، وبمغت نسبة إزالة المون ) (h2o2/sunlight, h2o2/uv٪( لمعمميات االتية وعمى التوالي ٪56.8، ٪70.01، ٪68.26، 65.19) .(h2o2/tio2/sunlight,h2o2/tio2/uv https://www.sciencedirect.com/science/article/pii/s0045653501001539 https://www.sciencedirect.com/science/article/pii/s0045653501001539 https://www.sciencedirect.com/science/article/pii/s0045653501001539 https://www.sciencedirect.com/science/article/pii/s0045653501001539 https://www.sciencedirect.com/science/article/pii/s0927775706003748 https://www.sciencedirect.com/science/article/pii/s0927775706003748 https://www.sciencedirect.com/science/article/pii/s0927775706003748 https://www.sciencedirect.com/science/article/pii/s0927775706003748 https://www.sciencedirect.com/science/article/pii/s0927775706003748 https://www.sciencedirect.com/science/article/pii/s0927775706003748 https://www.sciencedirect.com/science/article/pii/s0927775706003748 https://web.a.ebscohost.com/abstract?direct=true&profile=ehost&scope=site&authtype=crawler&jrnl=02535106&an=126280245&h=6wkrwrtqmtt9bsr%2bxs0z6pcy95nhff3rvkmfspnrwqe41je%2b%2f5xbguwik419kga39vsfwhqrkv8gdetc9dwtoa%3d%3d&crl=c&resultns=adminwebauth&resultlocal=errcrlnotauth&crlhashurl=login.aspx%3fdirect%3dtrue%26profile%3dehost%26scope%3dsite%26authtype%3dcrawler%26jrnl%3d02535106%26an%3d126280245 https://web.a.ebscohost.com/abstract?direct=true&profile=ehost&scope=site&authtype=crawler&jrnl=02535106&an=126280245&h=6wkrwrtqmtt9bsr%2bxs0z6pcy95nhff3rvkmfspnrwqe41je%2b%2f5xbguwik419kga39vsfwhqrkv8gdetc9dwtoa%3d%3d&crl=c&resultns=adminwebauth&resultlocal=errcrlnotauth&crlhashurl=login.aspx%3fdirect%3dtrue%26profile%3dehost%26scope%3dsite%26authtype%3dcrawler%26jrnl%3d02535106%26an%3d126280245 https://web.a.ebscohost.com/abstract?direct=true&profile=ehost&scope=site&authtype=crawler&jrnl=02535106&an=126280245&h=6wkrwrtqmtt9bsr%2bxs0z6pcy95nhff3rvkmfspnrwqe41je%2b%2f5xbguwik419kga39vsfwhqrkv8gdetc9dwtoa%3d%3d&crl=c&resultns=adminwebauth&resultlocal=errcrlnotauth&crlhashurl=login.aspx%3fdirect%3dtrue%26profile%3dehost%26scope%3dsite%26authtype%3dcrawler%26jrnl%3d02535106%26an%3d126280245 https://web.a.ebscohost.com/abstract?direct=true&profile=ehost&scope=site&authtype=crawler&jrnl=02535106&an=126280245&h=6wkrwrtqmtt9bsr%2bxs0z6pcy95nhff3rvkmfspnrwqe41je%2b%2f5xbguwik419kga39vsfwhqrkv8gdetc9dwtoa%3d%3d&crl=c&resultns=adminwebauth&resultlocal=errcrlnotauth&crlhashurl=login.aspx%3fdirect%3dtrue%26profile%3dehost%26scope%3dsite%26authtype%3dcrawler%26jrnl%3d02535106%26an%3d126280245 https://web.a.ebscohost.com/abstract?direct=true&profile=ehost&scope=site&authtype=crawler&jrnl=02535106&an=126280245&h=6wkrwrtqmtt9bsr%2bxs0z6pcy95nhff3rvkmfspnrwqe41je%2b%2f5xbguwik419kga39vsfwhqrkv8gdetc9dwtoa%3d%3d&crl=c&resultns=adminwebauth&resultlocal=errcrlnotauth&crlhashurl=login.aspx%3fdirect%3dtrue%26profile%3dehost%26scope%3dsite%26authtype%3dcrawler%26jrnl%3d02535106%26an%3d126280245 https://books.google.iq/books?hl=en&lr=&id=lslhaaaaqbaj&oi=fnd&pg=pr9&dq=%5b25%5d%09j.+c.+crittenden,+r.+r.+trussell,+d.+w.+hand,+k.+j.+howe,+and+g.+tchobanoglous,+mwh%e2%80%99s+water+treatment:+principles+and+design.+john+wiley+%26+sons,+2012.&ots=p_kbqzr-jy&sig=ecbycglrzpjpjl5ledjwmxgi9mk&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=lslhaaaaqbaj&oi=fnd&pg=pr9&dq=%5b25%5d%09j.+c.+crittenden,+r.+r.+trussell,+d.+w.+hand,+k.+j.+howe,+and+g.+tchobanoglous,+mwh%e2%80%99s+water+treatment:+principles+and+design.+john+wiley+%26+sons,+2012.&ots=p_kbqzr-jy&sig=ecbycglrzpjpjl5ledjwmxgi9mk&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=lslhaaaaqbaj&oi=fnd&pg=pr9&dq=%5b25%5d%09j.+c.+crittenden,+r.+r.+trussell,+d.+w.+hand,+k.+j.+howe,+and+g.+tchobanoglous,+mwh%e2%80%99s+water+treatment:+principles+and+design.+john+wiley+%26+sons,+2012.&ots=p_kbqzr-jy&sig=ecbycglrzpjpjl5ledjwmxgi9mk&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=lslhaaaaqbaj&oi=fnd&pg=pr9&dq=%5b25%5d%09j.+c.+crittenden,+r.+r.+trussell,+d.+w.+hand,+k.+j.+howe,+and+g.+tchobanoglous,+mwh%e2%80%99s+water+treatment:+principles+and+design.+john+wiley+%26+sons,+2012.&ots=p_kbqzr-jy&sig=ecbycglrzpjpjl5ledjwmxgi9mk&redir_esc=y#v=onepage&q&f=false https://www.sciencedirect.com/science/article/abs/pii/s1010603001004403 https://www.sciencedirect.com/science/article/abs/pii/s1010603001004403 https://www.sciencedirect.com/science/article/abs/pii/s1010603001004403 https://www.sciencedirect.com/science/article/abs/pii/s1010603001004403 https://www.sciencedirect.com/science/article/abs/pii/s1010603001004403 https://www.degruyter.com/view/j/jaots.1996.1.issue-1/jaots-1996-0104/jaots-1996-0104.xml https://www.degruyter.com/view/j/jaots.1996.1.issue-1/jaots-1996-0104/jaots-1996-0104.xml https://www.degruyter.com/view/j/jaots.1996.1.issue-1/jaots-1996-0104/jaots-1996-0104.xml https://www.degruyter.com/view/j/jaots.1996.1.issue-1/jaots-1996-0104/jaots-1996-0104.xml https://www.degruyter.com/view/j/jaots.1996.1.issue-1/jaots-1996-0104/jaots-1996-0104.xml iraqi journal of chemical and petroleum engineering vol.17 no.3 (september 2016) 91100 issn: 1997-4884 parameters affecting the thermodynamic efficiency of pem single cell and stack of cells (two cells) ghazwan ahmed mohammed* and amer abdulkhader shneat** college of engineering-university of baghdad *ghazwan_sultan@yahoo.com **amershneat@yahoo.com abstract in this work, thermodynamic efficiency of individual cell and stack of cells (two cells) has been computed by studying the variation of voltage produced during an operation time of 30 min as a result of the affected parameters:stoichiometric feed ratio, flow field design on single cell and feed distribution on stack of cells. the experiments were carried out by using two cells, one with serpentine flow field and the other with spiral flow field. these cells were fed with hydrogen and oxygen at low volumetric flow rates from 1 to 2 ml/sec and stoichiometric ratios of fuel (h2) to oxidant (o2) as 1:2, 1:1 and 2:1 respectively. the results showed that the highest voltage and efficiency can be obtained for the stoichiometric ratio of 1:2, while the ratio of 2:1 produced the lowest voltage and efficiency. also the best results were obtained with the serpentine flow pattern after comparing with the spiral flow pattern in a single cell. likewise it was proved that the voltage and efficiency are maximized when using the stoichiometry of 1:2, besides that the parallel feed connection of the stack of cells produced much power than the series connection. keywords: thermodynamic efficiency, proton exchange membrane fuel cell (pemfc), stoichiometric ratio, flow field design, feed distribution. introduction at the beginning of the 20th century, the equipment that converted chemical energy into electrical energy became more urgent due to the increase in the demand of electricity to minimize the energetically reliance on fossil fuels and lessen dangerous emissions into the atmosphere. fuel cell (fc) has high electrical efficiency compared to other sources [1]. nowadays fuel cells are very useful power sources than before, and they have the ability to satisfy the global power demands [2]. fuel cells are electrochemical devices that utilize hydrogen (h2) together with oxygen or (oxygen from air), to generate electricity and water. however there are many variants of this process, basing on the type of fuel cell and the fuel used [3]. different types of fuel cells which could be recognized by power produced into a range between few watts and megawatts. they are proton exchange membrane fuel cell (pemfc), direct methanol fuel cell (dmfc), alkaline fuel cell (afc), university of baghdad college of engineering iraqi journal of chemical and petroleum engineering mailto:ghazwan_sultan@yahoo.com mailto:**amershneat@yahoo.com parameters affecting the thermodynamic efficiency of pem single cell and stack of cells (two cells) www.iasj.netavailable online at: 6) 201 september( 3no. 7ijcpe vol.1 29 phosphoric acid fuel cell (pafc), molten carbonate fuel cell (mcfc), solid oxide fuel cells (sofc). all types of fuel cell are typically divided due to the nature of the electrolyte used [4]. proton exchange membrane (pem) fuel cell has many advantages such as low operating temperature, high power density, rapid startup, as well as excellent reliability and durability over other types of fuel cells [5]; it combines as very active unit the electrodes and the electrolyte. this design is well known as membrane electrode assembly (mea) [6]. during this process, the protons diffuse through the electrolyte membrane to the cathode, where they recombine to form hydrogen gas and react with oxygen to produce water using the simple redox reaction mechanism anode: h2 →2h + + 2e …(1) cathode:1/2o2+2h + +2e →h2o …(2) net reaction:h2+1/2o2→h2o+heat …(3) fig. 1: pem fuel cell design like any power generated device, pemfc performance usually is affected by many parameters like pressure, temperature, relative humidity and feed stoichiometric ratio [7]. the ratio of amount of actual flow rate of reacted components at inlet of pemfc to the amount is being consumed by the redox reaction is called stoichiometry. the product is water and in order to enhance the reaction rate, this water must be carried out from the cell by increasing the flow rate particularly on the cathode side where the chemical reaction took place and the water is continuously formed [8]. on the other hand, the purity of both supplied feed is extremely significant as its effectiveness on the operative behavior of cell. if hydrogen and oxygen are pure, then the needed flow rates are the same as the consumption and they are usually at low pressure. but when the feed of gases are not pure (oxygen from air) or impurities are existed with hydrogen in the feed, then nitrogen could be used to purge these accumulative materials or by the increasing of gas pressure to exclude these contaminants. because of the required flow feed is considered a design variable, this flow rate is related to the possible efficiency of reaction .the extremely higher flow rate the lower efficiency because of wasted hydrogen and when the flow rate is too low, the performance may suffer[9]. another design parameter is the flow field pattern. its impact on cell performance can be summarized by several functions like providing flow channels for reactive gases to their respective anodic and cathodic electrode surfaces, providing path for the removal of water generating from electrochemical reactions, considering as a mechanical support for the electrodes, serving as a current collector, electronically connecting one cell to another in a stack and acting as a physical barrier to prevent reactants and coolant fluids from mixing [10]. for conventional types of fuel cells like sofc, dmfc and pemfc, an individual cell produces 1 volt under operational conditions where the design of a single cell is usually used http://www.iasj.net/ ghazwan ahmed mohammed and amer abdulkhader shneat 29 )6201september ( 3no. 17ijcpe vol. www.iasj.netonline at: available for lab testing purposes. therefore to increase power for practical application, it is more convenience for utilizing multiple fuel cells stacked together than to use a single cell [11]. because of kinetic losses a single fuel cell has low power density. consequently, it was important to reduce these losses so as the design purpose of stack will be beneficial and more efficient [12]. for a fuel cell stack, beside these losses in every cell, the non-uniform distribution of fuel and oxidant to the multiple fuel cells can also cause decrease of the maximum available power output from the stack [13]. marston has studied the design, fabricating and assembling of a pemfc and evaluating cell efficiency by the variation of the h2/air feed ratio and acquired a representative plot of the fuel cell voltage as a function of time [14]. cai, hu, and zhang have found that the cell performance and mea resistance varied a little when utilizing thin membrane while the anode humidity changed from saturated to dry. the effectiveness of the cathode humidity was serious on the cell behavior [15]. guvelioglu and stenger have presented a mathematical model by studying cell efficiency for different hydrogen flow rates, air flow rates and humidification levels. they have revealed the sensitivity of current density to both gases flow rates as well as their relative humidity [16]. jang, chiu, yan and sun studied the behavior of single cell and stack of cells due to four effective key parameters (gas humidification temperature, cell temperature, assembled torsion, and gas flow rate). they revealed that the center cells have lower efficiency than the cells at both sides of the stack. also they found that the efficiency did not change with maximizing the anode gas stoichiometric ratio but they saw the increase action with the increase in the cathode gas stoichiometric ratio [17]. hsieh, huang and her found that the interdigitated flow design was having the largest pressure drop as much as the water accumulation at the early phase of ≤ 30 min in comparison to the rest of flow design shapes [18]. higier and liu, tried to optimize the serpentine flow design by developing a new technique in a house and separately measure the current density under the land and channel on different serpentine flow designs. every single flow field was tested with variable conditions and that showed the flow field with thinner land and channel was better [19]. taccani and zuliani focused on studying the influence of flow field geometry of high temperature (120-180 ˚c) polybenzimidazole (pbi) pem composite bipolar plates on the fuel cell behavior. with three different channel geometry (two serpentine and one parallel), it was shown that the serpentine flow pattern is better [20]. berning and kær studied the possibility of operating pemfc at low stoichiometric flow rate ratios using interdigitated flow pattern with dry feeds. it was shown when utilizing the stoichiometry (ξ c =1.2-1.5) at the cathode and as low as possible at the anode (ξ a =1) at ambient pressure leads to cell drying, and to avoid this case was to operate at or below 70 c˚ [21]. yadava, sahu and other researchers studied pemfc performance with different process parameters like temperature, pressure, relative humidity and feed flow rates. it was observed that increasing in the above parameters will enhance the fuel cell performance [22]. liu, li and wang investigated the effects of different gas flow field design on pemfc behavior. it was proven that serpentine flow channel is the best among all other flow designs [23]. http://www.iasj.net/ parameters affecting the thermodynamic efficiency of pem single cell and stack of cells (two cells) www.iasj.netavailable online at: 6) 201 september( 3no. 7ijcpe vol.1 29 in this work, thermodynamic efficiency of individual fuel cell and stack of fuel cells (two cells) has been computed by studying the variation of voltage produced during an operation time of 30 min as a result of the effected parameters like stoichiometric feed ratio, flow field design on single cell and feed distribution on stack of cells. experimental work 1. operating variables in this study the following variables were taken into consideration: 1. number of pem fuel cells (one or two fuel cells). 2. volumetric flow rates of the fuels (hydrogen and oxygen) fed to the fuel cell. 3. fuel ratios (hydrogen / oxygen). 4. type of flow field design (spiral or serpentine). 5. type of electrical fuel cell connections (series and parallel). 2. experimental rig the experimental rig is shown in figure 2 and it consisted of the following: 1. a pem fuel cell assembly which consisted of the following components: a) membrane electrode assembly (mea) which consisted of a polymer membrane type nafion 117 with active area of d = 8.8 cm and a total area of d = 10 cm. b) two catalytic electrodes (anode and cathode) which consisted of carbon loaded with 0.3 mg/cm² ptc (40%) for each electrode. c) two gas diffusion layers. d) two carbon end plates (10cm in diameter) with serpentine and spiral gas flow fields with groove width and depth of 1mm as shown in figures 3 and 4 respectively. e) two current collectors made from copper of 99.5% purity cut in circular shape. f) two teflon end plates with a canal for the rubber gasket. the teflon end plates sandwiches the above components with stainless steel bolts and nuts. 2. two cylinders one to store the hydrogen fuel and the other for the oxygen fuel. 3. two cylinder regulators one for the hydrogen cylinder and the other for the oxygen cylinder. 4. six calibrated flow meters. each three flow meters are connected in parallel to achieve the desired gas (hydrogen or oxygen) flow range. 5. pvc tubes to transport the fuel gas (hydrogen or oxygen) from the cylinder to the three parallel flow meters then to the pem fuel cell. 6. two inside feeds for hosing, pvc tubes inside the teflon end. 7. voltmeter with wire leads to read the voltage output of the pem fuel cell. fig. 2: experimental rig for pem fuel cell thermodynamic study fig. 3: serpentine carbon end with a rubber gasket fitted on top of a copper collector inside a teflon end http://www.iasj.net/ ghazwan ahmed mohammed and amer abdulkhader shneat 29 )6201september ( 3no. 17ijcpe vol. www.iasj.netonline at: available fig. 4: spiral carbon end with a rubber gasket fitted on top of a copper collector inside a teflon end 3. operation of pem fuel cell once the fuel cell was found to be functional, several tests were performed to determine its capabilities and enhance understanding of its operation. for all experiments, the behavior of produced cell voltage versus time was studied by using the following operating conditions: 1. atmospheric pressure (1 atm). 2. low operating temperature (ambient temperature). 3.1. single fuel cell a single fuel cell was assembled with membrane electrode assembly and carbon bipolar plates with spiral flow pattern. this fuel cell was operated with three different stoichiometric feed flow rate ratios. the stoichiometry ratios (sr) were 1:2, 1:1 or 2:1 for hydrogen to oxygen. the gas flow rate was from 1 to 2 ml/sec. the voltage produced was recorded for each one minute operation during a time of 30 minutes. another single fuel cell was assembled with the same assembling compositions but this time with serpentine flow pattern. this fuel cell operated with same three different stoichiometric feed flow rate ratios. the stoichiometry ratios (sr) were 1:2, 1:1 or 2:1 for hydrogen to oxygen. the gas flow rate was from 1 to 2 ml/sec. the voltage produced was recorded for each one minute operation during a time of 30 minutes. for each one of the two above fuel cells the power voltage begin rising till it reached the maximum value, after that the produced voltage begin to fall down until it reached the stable value through time evaluated by a stop watch through the experiment. 3.2. fuel cell stack (two cells) two fuel cells were stacked together each fuel cell was assembled with membrane electrode assembly and carbon plates with serpentine and spiral flow patterns. these fuel cells in the stack were operated with three different stoichiometric feed flow rate ratios. the stoichiometry ratios (sr) were 1:2, 1:1 or 2:1 for hydrogen to oxygen. the gas feed flow rate was from 1 to 2 ml/sec. the voltage produced was recorded for each one minute operation during a time of 30 minutes. the two fuel cells in the stack were connected in series. another type of operation for the stack of fuel cells was achieved by connecting these cells in parallel. for stack of fuel cells the power voltage begin rising till it reached the maximum value, after that the produced voltage begin to fall down until it reached the stable value through time evaluated by a stop watch through the experiment. results and discussion 1. voltage for all experiments and as illustrated in figures 5 to 8, the voltage produced due to cell or cells operation was suddenly rising and reaching to maximum value through 1 min and then falling down till it reached the steady state in the end of 30 min. this is by virtue of the kinetic potential losses, especially the sluggish oxygen reduction reaction which causes the potential loss or degradation in voltage produced at standard conditions even when pure oxygen gas was used. on the other hand, the hydrogen oxidation http://www.iasj.net/ parameters affecting the thermodynamic efficiency of pem single cell and stack of cells (two cells) www.iasj.netavailable online at: 6) 201 september( 3no. 7ijcpe vol.1 29 contributes very little to the polarization under normal operating conditions and has therefore gained less attention than the slowest process of oxygen reduction [24]. 2. effect of stoichiometric ratio of feed flow rates on fuel cell performance the effects of gas stoichiometric ratio on the performance of individual cell and cell stack are presented in figures 5 to 8. data values of voltage that were obtained as a result of feed stoichiometric ratio h2/o2=0.5 were the highest values during the time of operation compared to other feed ratios while for the ratio h2/o2=2.0, the results were the lowest values. this was due to water produced from chemical reaction, specifically on cathode side which affected the reaction rate by virtue of being a barrier to the oxygen gas molecules to reach the active sites on catalytic layer (cl), the location where the chemical reaction would take place. the decreasing in produced voltage when utilizing feed ratio (h2/o2=2), was a result of limitation in o2 mass transport through the gas diffusion layer (gdl) and the transportation of excess water to the flow channels. liquid water in the gdl was frequently assumed to be the major cause of mass transport limitations [25]. 3. effect of flow pattern of feed on fuel cell performance two flow patterns spiral and serpentine were used when operating the pem fuel cell. as can be noticed from figures 5 and 6 the serpentine flow pattern gave the highest produced voltage of 977mvolt for single fuel cell with h2/o2 fuel ratio of 0.5 while the spiral flow pattern gave a value of 885mvolt for the same conditions. it was obviously noticed that the serpentine channel design was favorable because of its capability to balance water removal and to control pressure drop to avoid water flooding and membrane dehydration as shown by [26, 27]. for other fuel cell with spiral flow pattern, it was found that there were tiny drops of water remaining in the flow channels when the cell was opened. it indicated that inefficient water removal was the justification of low power output. 4. effect of feed distribution on stack (two cells) of fuel cell performance the performance and power produced from two stacked cells by means of connection type was studied. as can be noticed from figures 7 and 8, the highest produced voltage was 1860 mvolt for stack with parallel feed and h2/o2 fuel ratio of 0.5. it was clearly shown that the stack of cells with the distributed feed in a parallel connection was preferred than series because each individual cell was being supplied with a uniform amount of fuel and oxidant compared with series connection. otherwise a non-uniform feed supply will lead to increasing non uniform chemical reaction and that will minimize the power of the entire stack [28, 29]. fig. 5: voltage produced with time from the operation of single pem fuel cell with three stoichiometric ratios (1:2, 1:1and 2:1) and spiral flow field pattern http://www.iasj.net/ ghazwan ahmed mohammed and amer abdulkhader shneat 29 )6201september ( 3no. 17ijcpe vol. www.iasj.netonline at: available fig. 6: voltage produced with time from the operation of single pem fuel cell with three stoichiometric ratios (1:2, 1:1and 2:1) and serpentine flow field pattern fig. 7: voltage produced with time from the operation of pem fuel cell stack connected in series with all three stoichiometry fig. 8: voltage produced with time from the operation of pem fuel cell stack connected in parallel with all three stoichiometry 5. thermodynamic efficiency of pem fuel cell the efficiency of a pem fuel cell was determined .both the enthalpy of chemical reaction and gibbs free energy are at standard state. for pem fuel cell the overall reaction was: h2 (g) + 1/2o2 (g) →h2o (l), with δg˚ = -237.18 kj/mole and δh˚ = 285.64 kj/mol [30]. theoretical efficiency, η of pem fuel cell based thermodynamic quantities was: η = δg˚/ δh˚ =-237.18/-285.64=83% …(4) the second law of thermodynamics shows this is the maximum efficiency that can be obtained. the anode and the cathode half-reactions in the pemfc are: h2 →2h + + 2e e˚ = 0.000 v (anode) 1/2o2 + 2h + + 2e → h2o e˚=1.229 v (cathode) …(5) thus the overall reaction potential equals 1.229 v, which is the maximum voltage possible [30]. the observed efficiency of the fuel cell which was defined as: %η = 100*e/ e˚ …(6) where e is the measured cell potential (produced voltage) and e˚ is the theoretical voltage, or 1229 mvolt for the pem cell. table 1 lists the maximum and average efficiency of all fuel cell operations performed in this study using equation 6. as can be noticed from table 1 the highest average efficiency is for the operation of single fuel cell with serpentine flow pattern and stack of cell with parallel connection with the h2/o2 fuel ratio of 0.5. http://www.iasj.net/ parameters affecting the thermodynamic efficiency of pem single cell and stack of cells (two cells) www.iasj.netavailable online at: 6) 201 september( 3no. 7ijcpe vol.1 29 table 1: the maximum and average efficiency of all fuel cell operations ratio flow pattern no. of fuel cells type of connection max %η ave. %η 0.5 spiral 1 non 94 72 1.0 spiral 1 non 92 70 2.0 spiral 1 non 89 67 0.5 serpentine 1 non 96 79 1.0 serpentine 1 non 94 77 2.0 serpentine 1 non 91 75 0.5 serpentine and spiral 2 series 86 72 1.0 serpentine and spiral 2 series 84 70 2.0 serpentine and spiral 2 series 82 67 0.5 serpentine and spiral 2 parallel 91 76 1.0 serpentine and spiral 2 parallel 88 74 2.0 serpentine and spiral 2 parallel 86 72 conclusions 1. degradation in voltage is a result of kinetic over potential. 2. for low feed flow rates, the increase in the amount of oxidant relative to the fuel stoichiometry will enhance the performance of pem fuel cell at low pressure and temperature. 3. the flow field design was an effective parameter in fuel cell operation, where serpentine flow pattern was more favorable than spiral one. 4. proper feed distribution in stack of cell will enhance the requirement of high efficiency. abbreviation fc=fuel cell pemfc= polymer electrolyte membrane fuel cell. dmfc= direct methanol fuel cell. afc=alkaline fuel cell pafc= phosphoric acid fuel cell mcfc=molten carbonated fuel cell sofc =solid oxide fuel cell mea= membrane electrode assembly sr=stoichiometric ratio cl=catalytic layer gdl=gas diffusion layer nomenclature η =thermodynamic efficiency ξ=feed stoichiometric ratio δh˚=change in enthalpy at std. conditions δg˚=change in gibbs free energy at std. conditions references 1. carrette l. fredrich k. a. and stimming u., (2001),”fuel cells fundamentals and applications”, fuel cells, from fundamentals to system, vol. 1(issue 1):pp. 5-39. 2. spiegel c., (2011),”pem fuel cell modeling and simulation using matlab”, chapter one-an introduction to fuel cells: pp. 1-14. 3. eg&g services inc., (2000)”fuel cell handbook, 5th ed.”, u.s. department of energy office of fossil energy national energy technology laboratory inc.: morgantown, west virginia, usa, available at: http://www.cientificosaficionados.c om/libros/pilas%20de%20comb ustible.pdf. 4. fuel cell basics, technology types, (2012) (www.fullcelltoday.com). http://www.iasj.net/ ghazwan ahmed mohammed and amer abdulkhader shneat 22 )6201september ( 3no. 17ijcpe vol. www.iasj.netonline at: available 5. wang y., chen k.s., mishler j., cho s.c. and adroher x.c., (2011)”a review of polymer electrolyte membrane fuel cells: technology, applications, and needs on fundamental research”, applied energy, vol. 88(issue 4):pp. 9811007. 6. d’arco s., ianuzzi d., pagano m. and tricoli p., (2005)”design criteria optimizing the use of fuel cell source in electric power system”, in: proceedings of the 16th ifac world congress, prague 7. weber a.z. and newman j., (2003)”transport in polymerelectrolyte membranes”: i. physical model, j electrochem soc, vol.150:pp.1008–1015 8. tohidi m., mansouri s.h. and amiri h., (2010)”effect of primary parameters on the performance of pem fuel cell”, international journal of hydrogen energy, vol. 35(issue 17):pp. 9338–9348. 9. barbir f., (2013)”chapter five – fuel cell operating conditions”, pem fuel cells (second edition), pages 119–157. 10. li x, sabir i., (2005)”review of bipolar plates in pem fuel cells: flow-field designs”, international journal of hydrogen energy, vol. 30(issue 4):pp. 359–371. 11. li p.w and suzuki k., (2004)”numerical modeling and performance study of a tubular sofc”, journal of the electrochemical society, vol. 151:pp. 548-557. 12. xianguo li., (2006)”principles of fuel cells”, new york: taylor & francis, isbn 1-59169-022-6. 13. kurz t., hakenjos a., kramer j., zedda m.and agert a., (2008)”an impedance-based predictive control strategy for the state-of-health of pem fuel cell stacks”. journal of power sources, vol. 180:pp. 742747. 14. marston m., (2005)”making green energy: designing, fabricating, and testing a pem fuel cell”, honors thesis, department of chemistry, washington state university. 15. cai y., hu j., ma h., yi b. and zhang h., (2006)”effect of water transport properties on a pem fuel cell operating with dry hydrogen”, electrochimica acta, vol. 51:pp. 6361–6366. 16. guvelioglu g.h. and stenger h.g., (2007)”flow rate and humidification effects on a pem fuel cell performance and operation”, journal of power sources, vol. 163:pp. 882–891. 17. jang j.-h., chiu h.-c., yan w.m. and sun w.-l., (2008)”effects of operating conditions on the performances of individual cell and stack of pem fuel cell”, journal of power sources, vol. 180:pp. 476– 483. 18. hsieh s.-s., huang y.-j. and her b.-s., (2009)”pressure drop on water accumulation distribution for a micro pem fuel cell with different flow field plates”, international journal of heat and mass transfer, vol. 52:pp. 5657–5659. 19. higier a. and liu h., (2010)”optimization of pem fuel cell flow field via local current density measurement”, international journal of hydrogen energy, vol. 352:pp. 144–2150. 20. taccani r. and zuliani n., (2011)”effect of flow field design on performances of high temperature pem fuel cells: experimental analysis”, international journal of hydrogen energy, vol. 36:pp.10282-10287. 21. kær s. k., (2012)”low stoichiometry operation of a proton exchange membrane fuel cell http://www.iasj.net/ parameters affecting the thermodynamic efficiency of pem single cell and stack of cells (two cells) www.iasj.netavailable online at: 6) 201 september( 3no. 7ijcpe vol.1 011 employing the interdigitated flow field – a modeling study”, international journal of hydrogen energy, publication at: http://www.researchgate.net/publica tion/257174370. 22. yadav m.k., sahu b.r., gupta b. and bhatt s., (2013)”effect of mass flow rate and temperature on the performance of pem fuel cell: an experimental study”, international journal of current engineering and technology, vol.3. available at: http://inpressco.com/category/ijcet 23. liu h., li p., juarez-robles d., wang k. and hernandez-guerrero a., (2014)”experimental study and comparison of various designs of gas flow fields to pem fuel cells and cell stack performance”, frontiers in energy research, available at: http://dx.doi.org/10.3389/fenrg.201 4.00002 24. wesselmarkm.,(2010)”electroch emical reactions in polymer electrolyte fuel cells”, kth chemical science and engineering, doctoral thesis, applied electrochemistry, school of chemical science and engineering, kungliga tekniska högskolan, stockholm. 25. pasaogullari u., wang c.y., (2004)”liquid water transport in gas diffusion layer of polymer electrolyte fuel cells”, journal electrochemist. soc., vol. 151:pp.399–406. 26. park j. and li x., (2007)”an experimental and numerical investigation on the cross flow through gas diffusion layer in a pem fuel cell with a serpentine flow channel”, j. of power sources, vol. 163:pp. 853-863. 27. li x., sbir i. and park j., (2007)”a flow channel design procedure for pem fuel cells with effective water removal”, j. of power sources, vol. 163:pp. 933942. 28. park j.w. and li x.g., (2006)”effect of flow and temperature distribution on the performance for a pem fuel cell stack”, journal of power sources, vol.162:pp. 444-459. 29. chen c.-h., jung s-p and yen s.-c., (2003)”flow distribution in the manifold of pem fuel cell stack”, journal of power sources, vol.173:pp. 249-263. 30. atkins p.w. (1990)”physical chemistry, 4th edition”, new york: w. h. freeman and company. http://www.iasj.net/ available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.19 no.4 (december 2018) 29 – 38 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: neaam f. hussain, email: neaam_1994@yahoo.com, faleh h. m. al mahdawi, email: fhmetr@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. estimating of pore pressure gradient in lower fars formation neaam f. hussain and faleh h. m. al mahdawi university of baghdad/ department of petroleum engineering abstract in petroleum industry, the early knowledge of “pore pressure gradient” is the basis in well design and the extraction of these information is more direct when the pore pressure gradient is equal to normal gradient; however, this matter will be more complex if it deviate from that limit which is called “abnormal pore pressure”, if this variable does not put in consideration, then many drilling problems will occur might lead to entire hole loss. to estimate the pore pressure gradient there are several methods, in this study; eaton method’s is selected to extract the underground pressure program using drilling data (normalized rate of penetration) and logs data (sonic and density log). the results shows that an abnormal high pressure is observed in lower fars formation started from mb5 member as a transition zone and increase gradually until reach the mb4 member and continuous to mb3 and mb2 then begin to decrease from mb1 which is consider a transition zone between high pore pressure zone and sub-pressure zone represented by jeribeeuphrate and upper kirkuk formations and back to normal pore pressure at middle-lower kirkuk formation. the dc-exponent method has been selected in estimating pore pressure gradient and considers the best one compared with logs data methods. keywords: pore pressure, pore pressure gradient, abnormal formation pressure, lower fars formation received on 07/10/8102, accepted on 13/11/8102, published on 01/08/8102 https://doi.org/10.31699/ijcpe.2018.4.4 1introduction the general meaning of pore pressure (or so-called formation pressure) is the pressure acting on the fluids contained in the pores of rocks. it is in theory equal to hydrostatic of fluids and it referred as normal pore pressure and practically it is may be equal, below or above that scale depending on different circumstances. when pore pressure above the normal pressure it is called overpressure or geopressure, and when below the normal limit it is called sub pressure, both of them considered as abnormal which is the most difficult and important stage in well planning, since it causes common drilling problems such as stuck pipe, kicks of wells, loss of circulation, blowout, lost hole and any single or combination of these problems increase the nonproductive time and therefore the total cost of drilling if not dealt professionally[1]. in worldwide oil fields, the problem of abnormal pore pressure is common in different formations, and its causes are attributed to combination of geological, geothermal and geochemical matter[2]. while drilling, there are three types of pressures will be faced, these pressures must be predefined and there is a plan to handle it to ensure a successful drilling process, the subsurface pressures are: overburden pressure, pore pressure, and fracture pressure. this research is covered three fields from missan oil fields (abu ghirab, fauqi, and halfaya) located near the southerneast borders of iraq. fig. 1. iraqi oil fields map and location of abu ghirab, fauqi and halfaya oilfields 2causes and origin of abnormal pressure 2.1. depositional effect a. undercompaction of shale as deposits become buried deeper in earth’s crust and rock layers formed, overburden pressure acting on these rock layers is increased, as a result, the layers compacted and its porosity decreased. https://doi.org/10.31699/ijcpe.2018.4.4 n.f. hussain and f. h. m. al mahdawi / iraqi journal of chemical and petroleum engineering 19,4 (2018) 29-38 03 therefore; the fluid within the pore spaces escaped from the compacted formation with slow sedimentation results a normal compacted formation. in many cases, with rapid sedimentation, in another meaning, there is no balance between the rate of compaction of layers and the rate of escaping of fluids, the fluid could not escape out of the pores, in addition of the possibility of cap rocks existence with zero permeability, the fluid applied extra pressure and resulted overpressure zone. b. deposition of evaporates the presence of evaporites (such as salt) resulting an overpressure formation due to several causes; the first one, the uplifting of salt resulting from its low density (in comparison with surrounding rock layers) creates additional tectonic stress which leads to fold, fault, and break out the nearby layers, also the flow of salt upward may shut the broken rocks above formations (usually limestone and dolomite) and that leads to capture the pressure within these formations thus, pressure increases from its normal limit and is defined as overpressure formation [3]. c. diagenetic processes diagenetic are any physical or chemical alteration in sediments as a result of high pressure and temperature, it may be due to volume changes and water generation, recrystallization and lithification of the rocks, and the formation of new minerals which lead to abnormal pressure formation. d. tectonic effects folding, faulting, and uplifting of underground layers is a results of tectonic effects. folding is caused by compression of rocks and applied an additional horizontal stress which compact the clay laterally; in case of water cannot escape, abnormal pressure will result. 2.2. structural causes a. hydrocarbon column in dipping reservoir, the distribution of fluids (water, oil, gas) is according of their densities. therefore; the pressure gradient of water will appear as abnormal in hydrocarbon column as compared with oil and gas. b. water table and artesian effect water table is the level of which ground water will rise in a well. the existence of aquifer with higher elevation than the well site causes an abnormality in the reservoir pressure due to the difference of topographic nature (outcrop of aquifer is higher than the drilling site). 2.3. thermodynamic processes a. organic matter transformation (thermal cracking) if thermal cracking of kerogen to form a simpler hydrocarbon compound at 90 degrees centigrade occurs in sealed environment, the result is high pore pressure. b. aquathermal effects the expansion of fluid within the rocks due to the increase of temperature with depth (geothermal gradient) will increase the pore pressure if the environment is totally sealed. c. permafrost in freezing areas, the pressure around the well bore developed as a result of thawing and re-freezing of permafrost causing collapse in surface casing [3]. 3methods of prediction pore pressure and detection abnormal pressure zones 3.1. drilling parameter method a. rate of penetration (rop) the basic concept of using rop in detecting abnormal pressure formation summarized in two points:  the compaction of any formation increases with depth due to the effect of overburden pressure, thus, rop is decreasing with depth (assuming the other parameters are constant).  the rocks are less compacted (more porous) in transition zone as compare with normal case, therefore; rop will increase with depth and gives an indication of overpressure zone presence. the rate of penetration increase because of the decreasing of the differential pressure (the difference between the drilling fluid pressure and formation pressure)[4]. b. d-exponent rate of penetration concept in detection of abnormal pressure zone is difficult to apply in practice since; the other drilling parameter (weight on bit, rotary speed, and bit size) cannot assume constant. a normalized rop produced from an empirical equation used to detect abnormal pressure formations instead of rop technique. bingham (1964) [5], suggest the following generalized drilling rate equation: ( ) (1) n.f. hussain and f. h. m. al mahdawi / iraqi journal of chemical and petroleum engineering 19,4 (2018) 29-38 03 jordan and shirley arranged equation (1) to be expressed in (d). the assumption of this equation based on the simplification of the drilled rocks value that doesn’t change and its value (a equal to one) and the rotary speed exponent (e equal to one). this number concluded by experiments to be so close to one. the lithology and rotary speed variable dependencies were removed from this equation; according to above, the application of this formula only to a single type of lithology at the assumed single rotary speed. when the value approximately equal one based on the assumed values with the limitations of the equation, then it’s not very restricted [6]. the following equation was produced based on these assumptions and accepting these limitations: ( ) ( ) (2) ( ) ( ) (3) equation (2) is for imperial units and (3) for metric units and they are known as the “d-exponent” equation. the values of penetration rate, rotary speed, weigh on bit, and bit size is can be measured at surface or it’s known. the d-exponent value determination by the depth of entire well plotted against it. observed that, the d-exponent value varies oppositely by the drilling rate (r), when the bit penetrate an overpressure zone, there will be a decrease in differential pressure leads to increase in the rate of penetration and obviously, d-exponent will be decreased. therefore; the plotting of d-exponent versus depth gives an indication of overpressure zone presence c. modified d-exponent (dc-exponent) rehm and mcclendon [7] corrected d-exponent for the effect of drilling mud weight (dc-exponent); it can be calculated by applying equation (4). (4) 3.2. logs methods a. sonic log (∆t) in normal shale compacted, the travel time decreases (velocity increases) with increasing burial depth as a result of decreasing shale porosity with continuity of matrix compression and that represented by fixed slop trend line varies from one region to another; the pressure of fluids within pores in this case called normal pore pressure. when an abnormal pore pressure formation penetrated, the data set of transit time will diverge toward abnormally high transit times for a given burial depth in case of high pressure formation, since the porosity is higher, or abnormally low transit time in subpressure formations. the amount of divergence of a given point from the established “normal compaction trend” is related to the observed pressure in adjacent shale formation [1]. b. resistivity log (r) hottman & johnson (1965) [8] developed a relationship between shale resistivity and abnormal pressure formations. they improved that less compacted shale rocks (high porosity) is less resistive than compacted shale due to high water content in the first type. they concluded that the normally compacted sediments have resistivity normal trend line increase with depth in shale section and any deviation from this trend gives indicate of abnormally pressure shale formation. c. density log ) using density log in estimating pore pressure gradient depends on the degree of shale compaction. normally compacted sediment is denser than less compacted case, so that, the normal compaction trend line for density log increase with depth; when penetrated an overpressure formation, the data set of bulk density deviate toward less than the normal trend due to high porosity and fluid content there. b. a. eaton (1975) [9] developed four equations used to predict overpressure formation from drilling parameter (d-exponent) data and well logs data (sonic, resistivity, and conductivity). the assumption of eaton’s method, as shown in terzaghi’s equation (eq. (5)), is the overburden pressure is the combination of pore pressure and vertical effective stress : (5) eaton proved the accuracy of his equations depending on the quality of the input data and the proficiency of users. the following are eaton’s equations for pore pressure estimation. eaton proved the accuracy of his equations depending on the quality of the input data and the proficiency of users. the following are eaton’s equations for pore pressure estimation. * ( ) + ( ) (6) * ( ) + ( ) (7) * ( ) + ( ) (8) * ( ) + ( ) (9) where, eq. (6) is for dc-exponent method, eq. (7) for sonic log method, eq. (8) for resistivity log method, and eq. (9) for density log method. n.f. hussain and f. h. m. al mahdawi / iraqi journal of chemical and petroleum engineering 19,4 (2018) 29-38 03 4estimating of pore pressure by eaton’s method using geolog software[10] 4.1. hydrostatic pressure gradient the first step in prediction pore pressure gradient is calculating hydrostatic pressure, the following equation used to calculate hydrostatic pressure. (10) air pressure could be calculated by equation (11) for onshore case, and water pressure calculated for offshore case only. ( ) (11) the above equation assumed that the porosity is interconnected and extends back to the surface through the overlying sediments; water pressure gradient is 0.465 psi/ft as default. the hydrostatic pressure gradient could be calculated by dividing the hydrostatic pressure by the depth of the interested point. 4.2. normal compaction trend line (nct) after calculating hydrostatic pressure, the next step is determining the normal compaction trend lines (nct) for input electrical logs (sonic transit time, velocity, density, and resistivity) or drilling data (d-exponent, sigmalog); this line could be determined by empirical methods (hottman, eaton, miller, bowers, and zhang) or manually according to the trend of data set in normal compacted shale formation. 4.3. overburden pressure gradient it is the pressure exerted, on a specific point, by the total weight of both the rock’s grains and fluids within the pores. the density of the combination is called the bulk density (ρb). the overburden pressure gradient varies with depth because of the variations of formation density; this is a result of the variations in the types of rocks, the densities of fluids, and the compaction degree of rocks[3]. in geolog software, the overburden pressure module computes overburden pressure from integrating bulk density log values over depth by the following equation: ∫ (12) where the water pressure is used for only offshore situation, and the 0.4334 factor is used for converting density (g/cc) to pressure, air pressure is calculated in onshore situation using equation (11). if density log information is not available for all intervals, it is often estimated from sonic transit time (pwave velocity); in ip software there are three methodologies those of gardner[11], bellotti et al[12] and lindseth[13] and the following equations represented these methods respectively: (13) where a and b are constants (a=0.23, b=0.25) (14) (15) where, eq. (14) is for consolidated formations and eq. (15) for unconsolidated formations. (16) overburden gradient could be calculated for any point by dividing the overburden pressure of this point by its depth. 4.4. pore pressure gradient the last step is to estimate pore pressure by eaton’s methods using equations from 6 to 9 which applied on dcexponent, sonic, resistivity, and density data respectively. 5cases under study the data of three fields (abu ghirab oilfield, fauqi oilfield, halfaya oilfield) represent in three wells are selected for this research which are: agcs-44, fqcs-32, , and hf013-m013. data sets available for each well are drilling parameter data (rop, rpm, wob, ) and logs data ( , ∆t, gr, cal, bit size). 6calculations 6.1. overburden pressure gradient the overburden pressure is calculated using equation (12). the water pressure is neglected because they are onshore wells and the air pressure is calculated using equation (11), the surface elevation and elevation of measurement reference is defined for each well in well header. in these cases, data is not available for whole depth so, it is estimated using sonic log data by applying gardner method using equation (13) which gives minimum average percentage error equal 3.6% as comparison with measured data of a specific interval. 6.2. normal compaction trend line (nct) determination a. dc-exponent method by applying equation (8) on drilling parameters data (rop, rpm, wob, bit size) the d-exponent is calculated; then, it is corrected for the effect of mud weight using equation (4) and the value of normal mud weight ( used is 1.08 gm/cc as referred in final well reports, dcn.f. hussain and f. h. m. al mahdawi / iraqi journal of chemical and petroleum engineering 19,4 (2018) 29-38 00 exponent results is obtained and plotted versus depth on semi-log paper; the interval of normal compacted shale is determined from final geological reports. in normal formation pressure zone the dc-exponent increase with depth as a result of decreasing rop; so that, the equation of nct is estimated from the trend of dcexponent in normal compaction shale interval as a function of depth with positive slop and the equation of it is constant for each field as follow: table 1. nct equations of dc-exponent field nct equation units abu ghirab oilfield fauqi oilfield halfaya oilfield b. sonic log (∆t) method the data set of ∆t decreasing with depth when plotting on semi-log paper; so that, the trend of nct for sonic log in normal compacted shale interval is with negative slop and constant as a function of depth for each field as follows: table 2. nct equations of ∆t field nct equation units abu ghirab oilfield us/ft fauqi oilfield us/ft halfaya oilfield us/ft c. density log ( ) method the data set of .has a positive slop trend line; since, in normal compacted interval the density of rocks increase with depth due to the increasing of compaction and reducing of porosity. the nct of rock density as a function of depth for each field is as follow: table 3. nct equations of . field nct equation units abu ghirab oilfield gm/cc fauqi oilfield gm/cc halfaya oilfield gm/cc 6.3. pore pressure gradient estimation pore pressure value will be estimated using eaton equations and depending on the normal compaction trend line for each field using three methods (dc-exponent, , and ) the overburden pressure gradient results obtained as referred in (6.1.) for each well, ), the normal pore pressure gradient is calculated using equation (10). the results are obtained by geolog 8.0 software. a. dc-exponent method pore pressure gradient by dc-exponent method is calculated using equation (6), the observed dc-exponent is calculated using equations (3) and (4) as mentioned above and the normal dc-exponent represented by normal compaction trend line and it is a function of depth, its equations for each field inserted in table 1. b. sonic log method pore pressure gradient by sonic method is calculated using equation (7), the normal transit time represented by normal compaction trend line and it is a function of depth, its equations for each field inserted in table 2. c. density log method pore pressure gradient by method is calculated using equation (9), the normal bulk density represented by normal compaction trend line and it is a function of depth, its equations for each field inserted in table 3. 7results the results of hydrostatic, overburden, and pore pressures and their gradients are inserted as figures below: fig. 2. pore pressure, overburden pressure, normal hydrostatic pressure and their gradients for agcs-44 by d-exp. method n.f. hussain and f. h. m. al mahdawi / iraqi journal of chemical and petroleum engineering 19,4 (2018) 29-38 03 fig. 3. pore pressure, overburden pressure, normal hydrostatic pressure and their gradients for fqcs-32 by d-exp. method fig. 4. pore pressure, overburden pressure, normal hydrostatic pressure and their gradients for hf013-m013 by d-exp. method fig. 5. pore pressure, overburden pressure, normal hydrostatic pressure and their gradients for agcs-44 by sonic method fig. 6. pore pressure, overburden pressure, normal hydrostatic pressure and their gradients for fqcs-32 by sonic method n.f. hussain and f. h. m. al mahdawi / iraqi journal of chemical and petroleum engineering 19,4 (2018) 29-38 03 fig. 7. pore pressure, overburden pressure, normal hydrostatic pressure and their gradients for agcs-44 by method fig. 8. pore pressure, overburden pressure, normal hydrostatic pressure and their gradients for fqcs-32 by method 8discussion the estimating of pore pressure using the three methods (dc-exponent, ∆t, and ) give approximated results as will be shown in figure (a-1) ; but, the results of dcexponent method will be taken into account for the following reasons:  it considers a real time record data and it inevitable presence in every well.  the data of sonic log dose not presence in the whole interval in some well also the data of density log presence for only reservoirs intervals to achieve the total cost optimization.  logs data records are for every (0.1 m); thus, these huge data cannot be handled issue only after pruning it and this cannot always be true. but it can be used as confirmation methods. by observing figures from fig. 1 to fig. 8 can be inferred that: 1in abu ghirab oilfield, the deviation of pore pressure from the normal limit start from mb5 member in lower fars formation and increase gradually until it reach the pick point in mb4 about (0.85 psi/ft) in (agcs-44) and continue in the same limit until it reach mb1 which consider a pressure transition zone between overpressure zone and sub-pressure zone represented by jeribe-euphrate and upper kirkuk when the whereas the lost circulation is a common problem there and back to normal limit equal approximately (0.468 psi/ft) at middle-lower kirkuk formation. 2in fauqi oilfield, the same behavior of underground pore pressure as abu ghirab oilfield; however, the pick point is concentrated in well fqcs-32 and reaches (0.71 psi/ft) at mb4 member in lower fars formation. 3in halfaya oilfield, the lower fars formation is shallower than abu ghirab and fauqi oilfields; the pore pressure gradient is the lowest there and reaches (0.68 psi/ft) as pick point at mb4 in hf013-m013. the previous results showed that the peak point of mb4 pore pressure gradient concentrated in agcs-44 well in abu ghirab oilfield at x= 726439 m; y= 3584470 m coordinates, fqcs-32 well in fauqi oilfield at x=741865 m; y=3555520 m coordinates , and hf013m-m013 at x=737332.; y=3506843.84 m coordinates. if these wells are dotted according to their location on the same paper, the locations of well according each other will be as the following figure: n.f. hussain and f. h. m. al mahdawi / iraqi journal of chemical and petroleum engineering 19,4 (2018) 29-38 03 fig. 9. location of agcs-44, fqcs-32, and hf013m013 the main reason of pore pressure increasing after the nature of precipitation in this area comes from the north, the taurus and zacros mountains are the result of the movement of arabian plate and its collision with the eurasian plate; this reaction began to fade gradually in the southern direction forming anticlines and domes turned into oil traps with the impact of lateral high pressure on their layers. that impact is represented in the 3d direction and the z direction will represent the pore pressure gradient for mb4 member in lower fars formation as follow: fig. 10. pore pressure gradient with distance in mb4 member in lower fars and when compared with the map of iraqi fields at fig. 1, this direction represent the point of convergence with the aforementioned collision zone. 9conclusion 1the main high pressure formation in this area is lower fars formation and its pore pressure gradient value varies from one location to another. 2the causes of abnormally increasing in pore pressure at lower fars formation are the nature of precipitation layers in this formation and the external pressures applied from the vertical and lateral directions causes. 3the lateral stresses are the results of a reaction resulting from movement of arabian plate and shocked with the eurasian plate. 4the overburden pressure gradient is not constant in this region and increase with depth. 5the drilling parameter method is better than logs methods in estimating pore pressure gradient. nomenclature symbols description unit air press: air pressure psi cal: caliper log in d: depth m : hole diameter (bit size) in d: drilling exponent dc: correct drilling exponent dcn: normal dc dco: observed dc : mean sea level depth m : elevation of measurement reference m gr: gamma ray gapi : normal mud weight gm/cc : actual mud weight gm/cc n: revolutions per minute rpm p: pore pressure psi : fracture pressure psi : hydrostatic pressure psi : water pressure gradient psi/ft r: rate of penetration m/hr : observed resistivity data ohm.m : normal resistivity data ohm.m : overburden pressure psi : elevation of drilling surface m : compressional velocity ft/us w: weight on bit tons water press: water pressure psi greek symbols description unit : sonic compressional transit time us/ft : normal transit time us/ft : observed transit time us/ft : shear transit time us/ft : bulk density of rock gm/cc : normal bulk density gm/cc : observed bulk density gm/cc n.f. hussain and f. h. m. al mahdawi / iraqi journal of chemical and petroleum engineering 19,4 (2018) 29-38 03 references [1] g. v. chilingar, v. a. serebryakov, and j. o. robertson jr, “seismic methods of pressure prediction,” in origin and prediction of abnormal formation pressure, 2002, pp. 169–188. [2] n. mohammed, s. maki, a. hasan, s. mahmood, and e. rhida, “well bore instability at shale section,” petroleum research and development center , baghdad. [3] h. rabia, “wellbore pressure,” in surface well control theory and equipment, 2017, pp. 9–64. [4] r. k. abbas, “pridiction of abnormal formation pressures in southern iraq,” ms.c thesis, university of baghdad, 1996. [5] m. bingham, “a new approach to interpreting rock drillability,” pp. 62, 46, 173–179, 1964. [6] j. r. jorden and o. j. shirley, “application of drilling performance data to overpressure detection,” j. pet. technol., vol. 18, no. 1, pp. 1387–1394, 1966. [7] b. rehm, r. mcclendon, and m. aime, “measurement of formation pressure from drilling data,” spe, 1971. [8] c. e. hottmann and r. k. johnson, “estimation of formation pressures from log-derived shale properties,” j. pet. technol., vol. 17, no. 06, pp. 717– 722, 1965. [9] b. a. eaton, “the equation for geopressure prediction from well logs,” fall meet. soc. pet. eng. aime, 1975. [10] paradigm, “geolog software 8.0.” . [11] g. l. f. gardner, l. w. gardner, and a. r. gregory, “formation velocity and density,” in the diagnostic basics for stratigraphic traps geophysics 39, 1974, pp. 770–780. [12] p. bellotti, v. di lorenzo, and d. giacca, “overburden gradient from sonic log trans,” spwla, london, march, 1979. [13] r. o. lindseth, “synthetic sonic logs – a process for stratigraphic interpretation,” geophysics, vol. 44, no. 1, pp. 3–26, 1979. appendix a comparison between dc-exponent, , and methods in estimating pore pressure gradient for fqcs https://www.sciencedirect.com/science/article/pii/s0376736102800280 https://www.sciencedirect.com/science/article/pii/s0376736102800280 https://www.sciencedirect.com/science/article/pii/s0376736102800280 https://www.sciencedirect.com/science/article/pii/s0376736102800280 https://www.sciencedirect.com/science/article/pii/s0376736102800280 https://www.onepetro.org/journal-paper/spe-1407-pa https://www.onepetro.org/journal-paper/spe-1407-pa https://www.onepetro.org/journal-paper/spe-1407-pa https://www.onepetro.org/conference-paper/spe-3601-ms https://www.onepetro.org/conference-paper/spe-3601-ms https://www.onepetro.org/journal-paper/spe-1110-pa https://www.onepetro.org/journal-paper/spe-1110-pa https://www.onepetro.org/journal-paper/spe-1110-pa https://www.onepetro.org/journal-paper/spe-1110-pa https://www.onepetro.org/conference-paper/spe-5544-ms https://www.onepetro.org/conference-paper/spe-5544-ms https://www.onepetro.org/conference-paper/spe-5544-ms https://library.seg.org/doi/abs/10.1190/1.1440465 https://library.seg.org/doi/abs/10.1190/1.1440465 https://library.seg.org/doi/abs/10.1190/1.1440465 https://library.seg.org/doi/abs/10.1190/1.1440465 https://library.seg.org/doi/abs/10.1190/1.1440922 https://library.seg.org/doi/abs/10.1190/1.1440922 https://library.seg.org/doi/abs/10.1190/1.1440922 n.f. hussain and f. h. m. al mahdawi / iraqi journal of chemical and petroleum engineering 19,4 (2018) 29-38 03 المسامي في تكوين الفارس االسفل تقدير تدرج الضغط هالخالص يكون ; في الصناعة البترولية ، تشكل المعرفة المبكرة عن "تدرج ضغط المسام" األساس في تصميم البئر الطبيعي.استخالص ىذه المعمومات في أكثر مباشرة عندما يكون تدرج الضغط المسامي مساويا لمتدرج يسمى "ضغط المسام غير وىذا ومع ذلك ، ستكون ىذه المسألة أكثر تعقيًدا إذا كانت تنحرف عن ذلك الحد الطبيعي" ، إذا لم يضع ىذا المتغير في االعتبار ، عندىا سيحدث العديد من مشاكل الحفر قد يؤدي إلى فقدان ، في ىذه الدراسة ؛ يتم اختيار طريقة إيتون الستخراج كامل لمبئر. لتقدير التدرج ضغط المسام ىناك عدة طرق ( وبيانات السجالت )سجل dc-exponentبرنامج الضغط تحت األرض باستخدام بيانات الحفر )مؤشر الحفر ) الصوت والكثافة(. تظير النتائج أنو لوحظ ارتفاع في تدرج الضغط المسامي يبدأ من تكوين الفارس االسفل lower fars ) يبدأ من المنطقوmb5 كمنطقو انتقاليو وتتزايد تدريجيا حتى يصل الىmb4 التي تعتبر mb1ثم يبدأ الضغط بالتناقص من منطقة mb2و mb3منطقة الضغط العالي في ذلك التكوين وتستمر الى -jeribeين التي تعتبر منطقة انتقاليو بين منطقة الضغط العالي ومنطقة الضغط المنخفض المتمثمو بتكو euphrate) ( و )( upper kirkuk ( ومن ثم تعود الى منطقة الضغط الطبيعي في تكوينmiddlelower kirkuk.) ( تم اختيارىا في تخمين تدرج الضغط المسامي وتم اعتبارىا dc-exponentان طريقة مؤشر الحفر ) لمجسات.أفضل طريقو بالمقارنو مع الطرق االخرى المتمثمو ببيانات ا ijcpe vol.9 no. 2 (june 2008) iraqi journal of chemical and petroleum engineering vol.9 no.2 (june 2008) 43-50 issn: 1997-4884 simulation of wiped film evaporator adil a. al-hemiri * , emad f. mansour ** and jamal a.l. al-ani ** * chemical engineering department, college of engineering, university of baghdad. ** chemistry and petrochemical industries research administration, ministry of science and technology. abstract a mathematical model and associated computer program were developed to simulate the steady state operation of wiped film evaporators for the concentration of glycerol-water solution. in this model, various assumptions were made to facilitate the mathematical model of the wiped film evaporator. the fundamental phenomena described were: sensible heating of the solution and vaporization of water. physical property data were coded into the computer program, which performs the calculations of this model. randomly selected experiments were carried out in a small scale wiped film evaporator from alval company, using different concentrations of the glycerol solution (10, 30 and 50 wt. %) for different feed rates (30, 50, 80, 100 and 120 l/h) and two values of steam jacket pressure (2 and 4 atm) to compare between experimental and simulation results. the statistical analysis gave correlation coefficient of 0.9972, average absolute error of 2.2527 % and f-test of 0.9639 which showed the high accuracy of the simulation work. keywords: wiped film evaporator, evaporators, simulation of film evaporators introduction evaporation is one of the main methods used in chemical industry for concentration of aqueous solutions that means the removal of water from solution by boiling the liquor in a suitable type of evaporator and withdrawing the vapor (coulson & richardson,1983). the objective of evaporation is to concentrate a solution consisting of nonvolatile solute and a volatile solvent. in the overwhelming majority of evaporations the solvent is water. normally, in evaporation the thick liquor is the valuable product and the vapor is condensed and discarded. agitated thin film evaporators, wiped film evaporators, are designed to spread a thin layer or film of liquid on one side of a metallic surface, with heat supplied to the other side. the unique feature of this equipment is not the thin film itself, falling and rising-film evaporators use thin liquid layers, but rather the mechanical agitator device for producing and agitating the film (apv, 2000). conventional heat transfer equipment may not be well suited for certain evaporation applications, particularly those involving heat sensitive products, viscous material or chemical constituents that exhibit fouling or foaming tendencies. for products like these, mechanically agitated thin-film evaporators are often selected over more conventional evaporators because of their batter process economics and performance (mutzenburg, 1965). for these applications, the heat transfer is not actually wiped or scraped but a highly agitated thin film is spread on to the metallic heat-transfer surface. agitation has the benefits in thin film equipment other than liquid turbulence. the blades assure even distribution of the liquid over the metal heat transfer surface; they eliminate any channeling of liquid as the liquid flows down the evaporator; the considerable shearing effect decreases the apparent viscosity of most liquids, thus improving internal heat and mass transfer (parker, 1965). also the heat transfer coefficient will be improved due to two reasons:  turbulence is included in the bulk of the fluid and near to the transfer surface reducing the effects of the resistance to heat transfer at the wall,  secondly where the surface is actually being scraped, the adhering film process liquid is constantly being university of baghdad college of engineering iraqi journal of chemical and petroleum engineering simulation of wiped film evaporator 44 ijcpe vol.9 no. 2 (june 2008) removed from the wall and distributed into the bulk of the liquid. at the same time fresh material is being presented to clean heat transfer surface. the heat flux and the evaporation capacity are affected by changes both in temperature drop and in the overall heat transfer coefficient. the temperature drop is fixed by the properties of the steam and the boiling liquid and except for the effect of hydrostatic head is not a function of the evaporator construction. the overall heat transfer coefficient, on the other hand, is strongly influenced by the design and the method of operation of the evaporator. in most services, a well-designed and properly specified unit can achieve a heat flux of 31550-78875 w/m 2 when processing typical organic, and as high as 157750 w/m 2 in some aqueous applications (abichandani et al , 1987). the overall resistance to heat transfer between the steam and the boiling liquid is the sum of five individual resistances: the steam-film resistance; the two scale resistance, inside and outside the tubes; the tube wall resistance; and the resistance from the boiling liquid. the overall coefficient is represented by equation (1). in most evaporators the fouling factor of the condensing steam and the resistance of tube wall are very small, and they are usually neglected in evaporator calculation. in agitated-film evaporator the tube wall is fairly thick so that the resistance may be a significant part of the total ((abichandani et al , 1987). 1 1 1 1 1 1 w o io i iw o k k ku h h ll l      (1) due to the difficulty of measuring the individual film coefficient in an evaporator, experimental results are usually expressed in terms of overall coefficients. these are based on the net temperature drop corrected for boiling-point elevation. the overall coefficient, of course, is influenced by the same factors influencing individual coefficients; but if one resistance (say, that of the liquid film) is controlling, large changes in the other resistance have almost no effect on the overall coefficient (freese & glover, 1979). freese & glover, (1979), also, reviewed a number of wiped film evaporators pilot-plants test on typical solvent recovery application performed at atmospheric conditions with steam as the heating medium. he showed that the overall heat transfer coefficient (u) ranging from 570850 w/m2ºc. parker (1965) reported the variation in the value of overall heat transfer coefficient for a thin film scraped surface evaporator (tfsse) between 1134 and 1985 w/m2.ºc. sangrame et al. (2000) studied the concentration of tomato pulp in a thin film scraped surface evaporator; the main body of the evaporator was 1.4 m high and 0.22 m in diameter. they found that for water as the feed, the overall heat transfer coefficient and evaporation rate ranged within 476.9-939 w/m2.ºc and 14.7-30.7 kg/h, respectively for tomato pulp, overall heat transfer coefficient, evaporation rate and final concentration (from 5.9% total solid initial concentration) were varied between 625.6910.9 w/m2.ºc, 13.22-33.72 kg/h and 8.02-19.21 % ts, respectively. the range of operating parameters were: feed flow rate 40.8-51.0 kg/h, steam temperature 65-80 ºc and rotor speed 355 rev/min. the optimum process parameters for the concentration of tomato pulp at 355 rpm rotor speed were found to be 40.3 kg/h feed flow rate and 73 ºc steam temperature. the optimum process parameters could give 840 w/m2.ºc overall heat transfer coefficient, 27 kg/h evaporation rate and 18 % total solids. chuaprasert et al. (1999) and chawankul et al. (2001) studied the steady state simulation of concentrating sugar syrup and orange juice respectively in atfe using aspenplus simulation program to develop the needed model. a rigorous heat exchanger model, heatx followed by the rigorous 2-phase flash model, flash2, was used to simulate the dominant effects of the atfe. the heat exchanger model was used to simulate the evaporator and required the heat transfer area (a), and the overall heat transfer coefficient (u). the output stream from the heat exchanger, a 2-phase stream consisting of concentrated orange juice and waster vapor, was fed to the 2-phase flash unit operating at the same pressure. the thermo-physical properties of both systems were not available in the aspen plus databank. they were therefore, determined experimentally and modeled as function of temperature and solid content. heat transfer coefficients were predicted using correlations and measured from process measurements. experimental and simulation results were compared and showed good agreement. mathematical treatment several assumptions are taken in order to facilitate the mathematical treatment used in the development of the simulation software. these assumptions are summarized as follows: * steady state operation. * plug flow unit with no backmixing and no radial mixing. * adiabatic mode of operation. * negligible energy input from the rotating wiper blades. adil a. al-hemiri, emad f. mansour and jamal a.l. al-ani 45 ijcpe vol.9 no. 2 (june 2008) the wiped-film evaporator for concentration of glycerolwater solution is divided into two sections according to the primary phenomenon occurring therein: sensible heating of the solution, and vaporization of water. the governing material and enthalpy balance equations for each of these sections are presented below (smith & van ness, 1987). in the sensible heating section, the solution stream is heated from its feed temperature to its initial boiling point; no phase change in this section and no change in the mass flow rate of solution stream occur. in an enthalpy balance about a (dz) increment in this section: rate of input h qd  (2) d h rate of output h z d z    (3) where  p rh wc t t  , and  i i sd q u d t t z    with no accumulation term, the rate of input must equal the rate of output, and the differential enthalpy balance equation is dh dq z 0 dz   (4) or    p r i i s d w c t t u a t t d z d z 0 d z        (5) neglecting any change in cp over a dz increment and recognizing that tr = constant then  i i s p d t u d t t w c 0 d z     (6) equation (6) can be integrated analytically between the limits of t = tf and t = tbp if ui and cp are assumed constant over this interval. admittedly this is not true, but the height or length of the preheating zone is quite small, which is generally less than 10% of the total height or length of the heat transfer zone, in the proposed applications. hence, average values of ui and cp based upon their values at the feed temperature and at the initial boiling point can be used in the equation. integration of this equation then yields: s f i s bp t tw cp δ z ln u t tid          (7) equation (7) thus determines the required height or length (z) of the preheating section. once boiling commences, the boildown ratio function developed previously enters into the calculations. the temperature of the solution stream is incremented in uniform step sizes of (t). the mass flow rate in (kg/h) of this stream at any temperature greater than the initial boiling point is computed from the boildown ratio as follows: 25ρ fw bdr  (8) and f 25 25 ρ f f ρ  (9) the rate of water vaporized over the z increment corresponding to the temperature increase t is then given by:    t t tv w w    (10) the enthalpy balance equation in this section has one additional output term (smith & van ness, 1987). rate of input h q  (11) v d h rate of output h z r h z d z           (12) where d v d w r d z d z    (13) subtracting the output term from the input term and equating the difference to zero, v d h q z r h z d z          (14) or    p r i i s v d w c t t u a t t z z r h z 0 d z            (15) simulation of wiped film evaporator 46 ijcpe vol.9 no. 2 (june 2008) again neglecting any change in cp over an increment then:    i i s p p r v d t u a t t w c c t t r r h 0 d z       (16) thermodynamically, however, for water  v p rh c t t   (17) where ( is the heat of vaporization of water at the temperature t. equation (16) can then be rewritten as  i i s p d t u a t t w c r 0 d z      (18) using average values of the variable values of ui, w, cp and , based upon their values at beginning and end of the finite t increment, then equation (19) can be written in the following finite difference form:   p i i s w c δ t δz u a t t λr    (19) finally, after approximating r with δz δv , equation (20) can be solved to yield the   p i i s λ δv wc δt δz u a t t    (20) this equation determines the increment height or length required to heat up the vaporized solution stream from t to (t+t) at which water is vaporized at the rate of δv kg/h. experimental work the liquids used in this work are non-ionic water supplied from al-mansour factory and glycerol from vegetable oils company. different concentrations (10, 30, and 50 wt % glycerol solutions) were prepared by weighing method. liquid viscosities varied from 0.6135.5 mpa.s, these values were measured using a fann vg meter (baroid) at 50 °c, which was applicable for this range. liquid densities varied from 985-1240 kg/m3. these values were found by measuring the mass of a known volume (pycnometer) at 50 °c. saturated steam, supplied from a fire tube steam generator, with different pressure (2-5 atm) was used as the heating media in the jacket of the evaporator. tap water (flowing at a pressure of 2 atm gauge and ambient temperature) was used as the cooling media in heat exchanger, sealing ring of the vacuum pump and the rotary shaft. experiments were carried out in wiped film evaporator supplied from alval engineering company. the evaporator consisted from the following parts: -main body of evaporator (stratavap model 8005). -graduated glass bottom. -separator cyclone. -condenser. -knock-out pot. -rotor drives (stratavap rotor). -vacuum pump (water ring sealing type). -different types of pumps for transfer solutions. the equipment was erected on a steel structure supplied with an electrical board for controlling and operating the different parts of the system. the system's utilities included steam supply, electrical stock and cooling water for sealing and cooling were all connected to the system. the main body of evaporator consisted of a jacketed cylinder with an inside diameter of 25 cm and active length of 116 cm made of stainless steel 316 l; the jacket was made from the same material with steam inlet pipe and outlet pipe for the condensate. the steam feeding pipe to the jacket had an inside diameter of 2.54 cm made from carbon steel with a regulating valve to control the pressure of steam in the jacket. as for the outlet pipe, it was made from carbon steel having the same diameter connected to a steam trap to permit the condensate steam only to exit from the jacket. in the top of main body of the evaporator a motor with a gearbox was installed to reduce the speed, fitted with belts to transfer rotation from motor to rotor parts of evaporator. the rotor part consisted of a shaft along the active part of the evaporator with a hung wiper equipped vertically to the shaft. a mechanical seal in the entrance of the shaft to the system existed to prevent the leakage of gases and vapors from the evaporator. at the end of evaporator a graduated glass dish bottom end was installed to collect the produced concentrated solution. table 1 experimental result. run no. feed conc. (wt. %) pressure depression (mmhg) steam pressure (atm) feed flow rate (l/h) final concentration (wt %) 1. 10 40 4 50 95 2. 10 40 4 30 98.5 3. 10 100 4 80 94 4. 10 100 4 100 89 5. 10 180 4 120 41 6. 30 40 4 30 99.4 7. 30 40 4 50 99.5 8. 30 120 4 100 95 9. 10 60 2 30 97 10. 10 100 2 50 94 11. 10 100 2 80 58 12. 10 180 2 100 26 13. 50 40 4 80 99.1 14. 50 40 4 100 99 adil a. al-hemiri, emad f. mansour and jamal a.l. al-ani 47 ijcpe vol.9 no. 2 (june 2008) results and discussion the effect of operating parameters on the performance of wiped film evaporator was studied using a simulation software. the studied parameters included: pressure depression, saturated steam pressure and feed volumetric flow rate. experiments were performed using different concentrations of glycerol-water solution (10-50 wt. %) and different feed flow rate (30-120 l/h). the results of the experiments conducted in the present study are given in table(1). the simulation program was proven to be successful by comparing with randomly selected practical experiments. where statistical analysis showed that the average absolute error, f-test and correlation coefficient of 2.25%, 0.997 and 0.964 respectively. during the experimentation and analysis, two distinct zones were recognized; preheating and evaporation. the preheating zone did not exceed 10% of the total evaporator length for all cases studied. effect of pressure depression five levels of pressure depression were chosen; these values were 80,120,160,200 and 400 mm hg (for a rotation speed of 480 rpm and a steam pressure of 4 atmospheres). the effect of pressure depression on the final concentration of glycerol and the influence of feed volumetric flow rate is shown in figure (1). it can be seen, as it should be, that the final concentration of glycerol increases with increasing the vacuum, i.e. lowering pressure depression. as the flow rate is increased the effect of pressure depression seems to be less effective. a decrease in the final concentration is noticed as the flow rate is increased (beyond 50 l/h) for all pressure depression levels , but it was , practically, constant below that. similar results were obtained by chawankul et al (2001) who studied the concentration of orange juice experimentally and compared the results with a simulation software using aspen plus. figure (2) shows the axial distribution of the overall heat transfer coefficient at the two extreme values of pressure depression used (80 and 400 mm hg) for a feed flow rate of 100 l/h, a rotation speed of 480 rpm and a steam pressure of 4 atmospheres. it can be seen that the overall heat transfer coefficient increased with increasing pressure depression and a maximum value was noticed at the point separating the preheating zone from the vaporization zone (5-10 cm. from entry). this is due to the decrease in the thermal conductivity of vapors compared to liquids. effect of steam pressure the effect of steam pressures (2, 3, 4 and 5 atm.) on the final concentration for different flow rates is shown in figure (3). these results were obtained at 480 rpm and 80 mm hg pressure depression. it can be observed that the final concentration increased with increasing steam pressure due to the increase of the temperature difference between the utility side (steam side) and the feeds side that caused enhancement of the evaporation rate. at low feed flow rate (below 50 l/h) the effect of steam pressure was not significant but increasing the feed flow rate beyond 100 l/h had caused the effect of steam pressure to be less pronounced. comparison of the effect of steam pressure with that of pressure depression, show that the effect of the latter, as expected, is sharper and more significant. figure (4) shows the axial distribution of the overall heat transfer coefficient at the extreme cases of steam pressure used (2 and 5 atm.). the results show that the overall heat transfer coefficient increased with decreasing steam pressure; this is due to the fact that at the lower pressure, the temperature difference is larger. effect of rotation speed figure (5) illustrates the effect of the speed of rotation and feed flow rate on the final concentration of glycerol. results indicate that increasing the feed flow rate caused in decreasing the final glycerol concentration and that increasing the speed of rotation caused significant increase in the final concentration; this increase was noticed to be lower at high feed flow rate. similar results were found by komori et al (1988). the effect of the speed of rotation on the axial distribution of the overall heat transfer coefficient is illustrated in figure (6). the figure show that the heat transfer coefficient reached a maximum at the point separating the preheating zone from the evaporation zone and it increased with increasing the speed of rotation. however the effect of the rotational speed was found to be less pronounced than the other parameters considered. these results were obtained for 480 rpm, 4 atm steam pressure and 100 l/h feed flow rate. simulation of wiped film evaporator 48 ijcpe vol.9 no. 2 (june 2008) volumetric flow rate, l/h 0 100 200 300 400 500 f in a l c o n c e n tr a ti o n , w t. % 0 20 40 60 80 100 2 atm 3 atm 4 atm 5 atm fig. 1: final concentration varies flow rate at different pressure depression volumetric flow rate, l/h 40 60 80 100 120 140 160 180 200 220 f in a l c o n c e n tr a ti o n , w t. % 0 20 40 60 80 100 80 mm hg 120 mm hg 160 mm hg 200 mm hg 400 mm hg fig. 1, final concentration versus flow rate at different pressure depression evaporator length, cm 0 20 40 60 80 100 120 u , w /m 2 k 400 500 600 700 800 900 1000 80 mm hg 400 mm hg fig. 2, axial distribution of overall heat transfer coefficient at different pressure dispersion (feed flow rate = 100 l/h) fig. 2: axial distribution of over all heat transfer coefficient at different pressure dispersion (feed flow rate =100 l/h) volumetric flow rate, l/h 0 100 200 300 400 500 f in a l c o n c e n tr a ti o n , w t. % 0 20 40 60 80 100 2 atm 3 atm 4 atm 5 atm fig. 3: final concentration versus flow rate at different steam pressure fig. 4: axial distribution of overall heat transfer coefficient at different steam pressure (feed flow rate = 100 l/h) fig. 5: final concentration versus flow rate at different rpm fig. 6: axial distribution of overall heat transfer coefficient at different rpm (feed flow rate = 100 l/h) evaporator length, cm 0 20 40 60 80 100 120 u , w /m 2 k 400 500 600 700 800 900 1000 2 atm 5 atm volumetric flow rate, l/h 0 100 200 300 400 500 f in a l c o n c e n tr a ti o n , w t. % 0 20 40 60 80 100 120 rpm 240 rpm 480 rpm 960 rpm evaporator length, cm 0 20 40 60 80 100 120 u , w /m 2 k 200 400 600 800 1000 1200 120 rpm 960 rpm adil a. al-hemiri, emad f. mansour and jamal a.l. al-ani 49 ijcpe vol.9 no. 2 (june 2008) conclusions the required height or length (z) of the preheating section was shown to be estimated using equation (7). the equation that determines the increment height or length required to heat up the vaporized solution stream from t to (t+t) at which water is vaporized at the rate of δv kg/h is given by equation (20). the success in applicability of the designed simulation program was proven by the comparison with randomly selected practical experiments. statistical analysis of the comparison showed that the average absolute error, correlation coefficient and f-test were 2.253 %, 0.997, and 0.964 respectively. two distinct zones of operation were observed; preheating and evaporation. and at the point of separation of these two zones the value of heat transfer coefficient reached a maximum. the range of the overall heat transfer coefficient observed in this study was 176-1263 w/m 2 0 k. increasing the pressure depression decreased the final concentration of the product but increased the heat transfer coefficient. altering the steam pressure did not affect the final concentration significantly, but increasing it caused a lowering in the value of the heat transfer coefficient. increasing the speed of rotation increased the final concentration and, also, increased the heat transfer coefficient, where a 66% increase was observed when increasing the speed from 120 to 960 rpm. nomenclature a : heat transfer area m 2 bdr : boil down ratio -- cp : specific heat of fluid kj/kg 0 k d : column diameter m f : mass flow rate kg/s h : heat transfer coefficient kj/m 2 s 0 k h : heat input by flow of fluid stream kj/s k : thermal conductivity kj/m 3 s 0 k l : thickness m q : heat input by conduction through wall kj/s r :defined by equation (13) kg/ms t : temperature ° k u : overall heat transfer coefficient kj/m 2 s 0 k v : rate of vaporization kg/s w : flow rate defined by equation (8) kg/s z : column height m greek letters λ : latent heat of vaporization kj/kg ρ : density kg/m 3 π : pi --- subscripts bp : boiling point f : fluid i : inside o : outside r : reference s : steam v : vapour w : wall 25 : at 25 ° c reference 1. abichandani h., sharma s.c., and heldman d.r., (1987) “hydrodynamics and heat transfer in thin film scraped surface heat exchanger: a review”, journal of food process engineering, 9, 143-172. 2. apv company, "evaporator handbook", (2000) 4 th edition, ehb-955, www.apv.com. 3. chawankul n., chuaprasert s., douglas p.l. and luewisutthichat w., (2001) "simulation of an agitated thin film evaporator for concentrating orange juice using aspenplus”, journal of food engineering, 47, 4, 247-253. 4. chuaprasert, s., p. l. douglas, m. nguyen, (1999)"data reconciliation of an agitated thin film evaporator system using aspenplus", j. of food engineering, 39, 261267. 5. coulson j. m., and richardson j. f., (1983) “chemical engineering vol. 2”, 3 rd edition, pergamon press . 6. freese h.l., and glover, w.b., (1979) "mechanically agitated thin-film evaporators", chem. eng. pro. , jan., 52-58. 7. mutzenburg a. b., (1965) "agitated thin-film evaporators, part.1: thin film technology", chem. eng. 72 (19), 175-178. 8. parker n., (1965) "agitated thin-film evaporators, part.2: equipment’s and economics", chem. eng., 72 (19), 179-185. http://www.apv.com/ simulation of wiped film evaporator 50 ijcpe vol.9 no. 2 (june 2008) 9. sangrame, g., bhagavathi, d., thakare, h., ali, s. and das, h., (2000) "performance evaluation of a thin film scraped surface evaporator for concentration of tomato pulp", j. food eng., 43, 205-211. 10. smith j.m. and van ness h.c., (1987) “introduction to chemical engineering thermodynamics”, 4 th edition, mcgraw-hill book company, new york. iraqi journal of chemical and petroleum engineering vol.15 no.2 (june 2014) 2737 issn: 1997-4884 research octane number improvement of iraqi gasoline by adsorption of n-paraffins using zeolite molecular sieves nada sadoon ahmedzeki and arowa salah alddin mahdi chemical engineering department, college of engineering, university of baghdad, baghdad, iraq abstract this study focused on the improvement of the quality of gasoline and enhancing its octane number by the reduction of n-paraffins using zeolite 5a. this study was made using batch and continuous mode. the parameters which affected the n-paraffin removal efficiency for each mode were studied. temperature (30 and 40 ˚c) and mixing time up to 120 min for different amounts of zeolite ranging (10-60 g) were investigated in a batch mode. a maximum removal efficiency of 64% was obtained using 60 g of zeolite at 30 ˚c after a mixing time 120 min. the effect of feed flow rate (0.3-0.8 l/hr) and bed height (10-20 cm) were also studied in a continuous mode. the equilibrium isotherm study was made using different amounts of zeolite (2-20 g) and then simulated for n-hexane and nheptane using langmuir, freundlich isotherms. kinetic of the adsorption of n-hexane and n-heptane was investigated using pseudo first order, pseudo second order and intra particle model. the research octane number (ron) for some selected samples was measured to show the effect of the removal on the quality improvement of gasoline. results showed an increase of 5.5 units in ron using 40 g zeolite at 40 ˚c and after 120 ˚c min. also an increase in 7 units was obtained in the continuous mode after 30 min using flow rate of o.3 l/hr and bed height of 10cm. experimental data for n-hexane and n-heptane was found to fit langmuir isotherm with correlation coefficient of 92.7% and 88.8% for n-c7 and n-c6, respectively. adsorption of n-hexane and n-heptane was found to follow second order kinetics with correlation coefficient of 99.9% and 99.8% for n-c7and nc6 respectively. this study revealed a favorable adsorption of n-paraffins on zeolite 5a as indicated by the separating factor of 0.6 and 0.44 for n-c7and n-c6, respectively. keywords: octane number upgrading, adsorption, zeolite 5a. introduction separation and purification of mixtures by selective adsorption of one or more of its components on a micro or meso-porous solid adsorbent is a major unit operation in the chemical, petrochemical, environmental, medical, and electronic gas industries. the main reasons are as follows: commercial availability of a spectrum of porous adsorbents (zeolites, activated carbons, silica and alumina gels, polymeric sorbents, etc.) which offer many different choices of core adsorptive properties (equilibria, kinetics, and heats) for a given gas iraqi journal of chemical and petroleum engineering university of baghdad college of engineering research octane number improvement of iraqi gasoline by adsorption of n -paraffins using zeolite molecular sieves 28 ijcpe vol.15 no.2 (june 2014) -available online at: www.iasj.net separation or purification application. zeolite 5a is used in two major separation processes. the first is the separation of linear and isoparaffins by allowing the former to pass through the channels and the latter is not. the second process is air separation where the equilibrium loading of nitrogen on the 5a zeolite is much greater than that of oxygen and argon [1]. in spite of the potential advantages of adsorptive separation, it did not achieve wide commercial acceptance until the introduction of the uop sorbex process in the early 1960s invented by uop in the 1960s, the sorbex technique was the first largescale commercial application of continuous adsorptive separation. the first commercial sorbex unit, a molex unit for the separation of linear paraffins, came on-stream in 1964. most applications of the sorbex process deliver high-purity products that can be sold or used in downstream technologies. this process offered a truly continuous adsorptive separation process that produced products with essentially constant compositions [2]. octane rating or octane number is a standard measure of the performance of a motor or aviation fuel. the higher the octane number, the more compression the fuel can withstand before detonating. in broad terms, fuels with a higher octane rating are used in high-compression engines that generally have higher performance. in contrast, fuels with low octane numbers are ideal for diesel engines. use of gasoline with low octane numbers may lead to the problem of engine knocking [3]. the most common type of octane rating worldwide is the research octane number (ron). ron is determined by running the fuel in a test engine with a variable compression ratio under controlled conditions, and comparing the results with those for mixtures of iso-octane and n-heptane. modern automobile engines require high octane gasoline for efficient operation. previously lead had been added to gasoline to increase the octane number. however, with the removal of lead from the gasoline pool due to environmental concerns, other methods for increasing the octane number are needed. however, mtbe, while generally less toxic than lead, has been linked to ground water contamination. at the same time, some of the high octane components normally present in gasoline, such as benzene, aromatics, and olefins, must also be reduced. the coking gasoline is usually used as the blending components of automobile gasoline [4] or the feed of the catalytic reforming process after being hydrogenated. obviously, a process which will increase the octane of gasoline without the addition of toxic or environmentally adverse substances will be preferable [5-7]. some versions of uop’s hydroisomerization processes use highly active zeolite-based, pt containing hydroisomerization catalysts, such as uop i-7, which contains modified synthetic (largeport) mordenite. in the presence of hydrogen at moderate conditions, such catalysts optimize isomerization and minimize hydro cracking [8]. to further increase octane level, products from a hydroisomerization unit can be sent to the molex process, where the remaining lower-octane, linear paraffins are separated from the other compounds by using a zeolite adsorbent and a liquid desorbent; the molex process is an example of uop’s sorbex simulatedmoving-bed technology [9]. the extracted linear paraffins are recycled to the hydro isomerization unit, and the remaining higher-octane fraction is recovered for gasoline blending. the combination of http://en.wikipedia.org/wiki/engine_knocking http://en.wikipedia.org/wiki/engine http://en.wikipedia.org/wiki/compression_ratio http://en.wikipedia.org/wiki/compression_ratio nada sadoon ahmedzeki and arowa salah alddin mahdi -available online at: www.iasj.net ijcpe vol.15 no.2 (june 2014) 29 the hydroisomerization and molex processes boosts the research octane number of a typical feed from 68–70 to 89–92. shell and union carbide are commercially using zeolite caa (¼4.6a°, also referred to as zeolite 5a) in the separation of linear paraffins from iso-paraffins in their tip process (total isomerization process). in this process, the linear c5 and c6 paraffins were first isomerized to the thermodynamic equilibrium where after the linear paraffins are selectively adsorbed on zeolite caa and recycled to the isomerization reactor [10]. the isomerization catalyst of the tip process is zeolite pt-h-mordenite, showing the catalytic potential of zeolites. in this case, the zeolite not only serves as a support for the platinum particles but also as a solidacid catalyst [11]. the tip process (>100 plants worldwide) is an excellent example of the versatile nature of zeolites in industrial processes. the demand for new zeolite is, however, modest because of the long service life of the separating and the isomerizing zeolites. to achieve higher octane levels, uop’s tip total isomerization process uses the oncethrough isomerization process combined with uop’s iso siv process, which uses size-selective zeolite adsorption of the unreacted linear paraffins so that they can be recycled and converted to extinction. both the tip and iso siv processes originally were developed at union carbide’s molecular sieve department, now part of uop. [12]. this study represents a first unique study of commercial light naphtha obtained from al dora refinery as an a attempt to upgrade the quality of gasoline by improving its research octane number. the objective of the present work is to study the removal of n-paraffins from iraqi light naphtha using zeolite 5a in batch mode and continuous mode adsorption experiments. in the batch mode, the influence of temperature, zeolite dosage and agitation time were studied while in the continuous mode, the influence of bed height and feed flow rate on the removal of n-alkanes were studied in a fixed bed adsorber. for both modes, the effect of removal efficiency on ron was tested for selected samples. the equilibrium adsorption isotherms using the most common models and the kinetics for the adsorption of n-hexane and nheptane using pseudo-firstorder, pseudosecond-order and intra-particle diffusion were also investigated. experimental work hydrogenated light naphtha, consisting 35.134 wt. % of total nparaffins, was supplied by al-durra refinery. zeolite 5a was supplied by arab company for detergent chemicals (0.833 mm white spherical, pore volume 11.1% (v)). the zeolite samples were activated by heating for 2 hours in a stepwise manner from room temperature to 200 ˚c. equilibrium study the procedure involved filling five flasks with 50 ml of hydrogenated light naphtha. amounts of zeolite 5a (2, 5, 10, 15, and 20 gm) were added into the flasks, sealed and shaken for 24 hours at speed 200 rpm. the supernatant after filtration by buchner funnel was analyzed for the remaining amount of n-paraffins (pentane, hexane and heptane) by gas chromatography. the equilibrium amounts of n-paraffins sorbed by zeolite qe (g/g zeolite.) in the sorption system were calculated using the mass balance: qe = v (co-ce) /m …(1) where v is the solution volume (l), m is the amount of sorbent (g), and co and ce (g/l) are the initial and research octane number improvement of iraqi gasoline by adsorption of n -paraffins using zeolite molecular sieves 30 ijcpe vol.15 no.2 (june 2014) -available online at: www.iasj.net equilibrium concentration, respectively. adsorption kinetic experiments batch mode a specified amounts of the zeolite (10, 40, 50 and 60 g) were added in a 500 ml conical flask containing a 300 ml of light naphtha and temperature was set as 30 or 40 ˚c. samples were withdrawn at different agitation time (15, 30, 60, 90, 120 and180 min). each samples was filtered using whatman31 filter paper and analyzed for total nparaffins concentration. a schematic representation of the batch adsorption unit is shown in fig. 1. fig. 1: schematic diagram of laboratory batch adsorption unit continuous mode a 2.54 cm quartz column and 35cm long, packed with zeolite 5a was used as the adsorption column. about 41.2 and 82.4 g of the 5a zeolite were packed in the vertical column having a bed length of 10 and 20 cm, respectively. down flow conditions were used in the experiment. the feed of light naphtha was pumped into the fixed-bed reactor through a distributer at a flow rate of 0.3 and 0.8 liter hr −1 as measured by a rotameter n-paraffin content of the effluent was sampled at different operating intervals up to 120min and analyzed by gc. fig .2 shows a diagram of the fixed bed adsorption unit. fig. 2: schematic diagram of laboratory fixed bed adsorption unit results and discussions batch mode effect of contact time the total removal efficiency of nparaffins is presented in figs. 3 to 6. it can be seen that the removal by adsorption process proceeded in two stages. an initial rapid increase in the first 15 minutes of contact time is very sharp, and becomes slower and the uptake rate gradually decreases with the increase of contact time. this is due to the continuous filling of the adsorption sites as the time proceeds and to continuous uptake of these materials until reaching equilibrium. some fluctuations are seen around equilibrium due to the adsorption desorption phenomena. moller et al. [13] had obtained such results by studying the sorption uptake of nbutane and n-hexane on zeolite 5a and zsm-5. fig. 3: the relation between the removal efficiency of total n-paraffins with temperature using 10 g of zeolite in 300ml of light naphtha 0 0.2 0.4 0.6 0.8 1 0 50 100 150 200 r to t time(min) 30 ̊ c 40 ̊ c nada sadoon ahmedzeki and arowa salah alddin mahdi -available online at: www.iasj.net ijcpe vol.15 no.2 (june 2014) 31 fig. 4: the relation between the removal efficiency of total n-paraffins with temperature using 40g of zeolite in 300ml of light naphtha fig. 5: the relation between the removal efficiency of total n-paraffins with temperature using 50g of zeolite in 300ml of light naphtha fig. 6: the relation between the removal efficiency of total n-paraffins with temperature using 60g of zeolite in 300ml of light naphtha effect of temperature the effect of temperature on reduction of nparaffins was studied at 30 ˚c and 40 ˚c and at different amounts of zeolite of 10, 40, 50 and 60 g. as a general trend, increasing the temperature had a negative effect on the reduction of nparaffins; i.e. increasing the temperature decreases the adsorption of the solute; therefor, desorption or regeneration of the adsorbent is normally achieved by raising the bed temperature [1]. this result is in agreement with wender et al [14] as they found a decrease in the adsorption capacity for individual system of n-hexane up to n-dodecane with increasing temperature. in our study on the cut of light naphtha which is very heat sensitive for it contains different compounds of aromatics, naphthenes, iso-paraffins and nparaffins with different vapor pressures, so it is expected that high interference on the uptake of adsorbent to linear paraffin and a continuous adsorption/desorption process occurred. this result agrees well with the result of nahdhir et al [15] who studied the adsorption of methane in the presence of ethane or ethylene and concluded that the model was better fit for paraffin system and not for others and a separation can be achieved easily at any conditions but was the best at low temperature and pressure. effect of amount of zeolite fig. 7 shows the results of adsorption study carried out with different adsorbent dose. it was found that with increasing dosage of adsorbent the rate of removal of adsorbate (n-c7) increases. the data obtained reveals that there is a substantial increase in adsorption when amount of adsorbent is increased from 2 to 20 g. increasing the amount of the adsorbent offers more adsorption sites available and ready for higher uptake [16]. fig. 7: effect of amount of adsorbent for the removal of n-c6,n-c7and n-ct using 5a zeolite:ambient temperature; time = 24 h 0 0.2 0.4 0.6 0.8 1 0 50 100 150 200 r to t time(min) 30 ̊ c 40 ̊ c 0 0.2 0.4 0.6 0.8 1 0 50 100 150 200 r to t time(min) 30 ̊ c 40 ̊ c 0 0.2 0.4 0.6 0.8 1 0 50 100 150 200 r to t time,min 30 ̊ c 40 ̊ c 0 0.2 0.4 0.6 0.8 1 0 10 20 30 r wt.(g) c6 c7 c5 ct research octane number improvement of iraqi gasoline by adsorption of n -paraffins using zeolite molecular sieves 32 ijcpe vol.15 no.2 (june 2014) -available online at: www.iasj.net competitive adsorption of nparaffins by observing fig. 8, it can be seen that the uptake of n-c7 on 5a zeolite was higher than n-pentane and nhexane. this is due to the fact that long chain hydrocarbons are favorably adsorbed on 5a zeolite [1]. the removal efficiency of n-c7was 53% after 30 minutes while 45% of n-c6 and 27% of n-c5 at the same time. after 180 minutes, the adsorption of nc7 reached a maximum value where 61% was removed. the removal efficiency of n-c6 was 46% while for n-c5 a continuous decrease of the removal efficiency until reaching 14%. the decrease for n-c5 can be attributed to the desorption occurring in the zeolite structure and replacement by other compounds of higher affinity; i.e. n-c6 and n-c7. fig. 8: the removal of n-hexane, n-heptane and n-pentane using 5a zeolite: temperature = 40 c; wt. = 40g effect removal of n-paraffins on ron from table 1, it can be seen that the removal of nparaffins and specifically n-heptane improves the ron for cut of light naphtha which is studied in the present work. the ron of n-heptane is zero so the reduction in this constituent greatly enhance the fuel property. removing about 56% of n heptane increases the ron of light naphtha .this table indicates that the amount of n-c7 adsorbed is higher than n-c6 using 40 g of zeolite so that the ron increases 5.5 units from (64.5 to70). table 1: research octane number for light naphtha in the batch mode wt %rtot %rc7 ron increase in ron 10 31. 56.26 66 1.5 40 30.1 61.49 70 5.5 continuous mode effect of flow rate the effect of flow rate 0.8 and 0.3 l/h on the adsorption of n-paraffins is shown by breakthrough curves drawn in figure 9.the adsorbent bed height was fixed at 10 cm and inlet concentration of n-paraffins of 35.134%. it can be seen that the saturationtime decreases for n-paraffin with flow increase.this can be explained by that incearsing the rate of adsorption and the saturation of bed occurs at a shorter time. besides, the effluent concentration for higher flow rate is higher as compared to low flow rate at constant time because the adsorbate will not have enough time to diffuse into the pores of adsorbent. fig. 9: breakthrough curves for adsorption nparaffins at z=10 cm effect of bed height two bed heights had been studied as 10 and 20 cm which represent a weight of 41.2 and 82.4 g, respectively. the flow rate was fixed on 0.3 l/hr. fig. 10 shows the breakthrough curves for the two bed heights at constant flow rate of 0.3 l/hr. 0 0.2 0.4 0.6 0.8 1 0 100 200 % r time,min c5 c6 c7 nada sadoon ahmedzeki and arowa salah alddin mahdi -available online at: www.iasj.net ijcpe vol.15 no.2 (june 2014) 33 it can be observed that, as the bed height increased the time needed for breakpoint increases. this shows that for a value of ce/c0=0.6, the time is (5min) and (17min) for 10 and 20 cm respectively. the increase of bed height means an increase in the mass of the adsorbent packed in the column which offers more available adsorption sites for adsorbate to be adsorbed. furthermore, the bed would be saturated in less time for smaller bed height. fig. 10: breakthrough curves for adsorption n paraffins at q=0.3l/h effect of removal of n-paraffins on ron the effect of the reduction of nparaffins is clarified by the measurement of ron for selected samples. records are shown in table 2. the time for a specified volume of (300 ml) of the effluent from the start of operation is shown along with feed flow rate and bed height. in these experiments, the feed ron was 66.2. values of the increase can be attributed to the reduction of n-paraffins present in the fuel. for bed height of 10 cm and 0.3 l/h, an increase of 7 units is obtained, and the quality of the fuel is enhanced. table 2: ron for the continuous mode time, min feed flow rate l/h bed height (z) cm ron increase 20 0.8 10 67.1 0.9 30 0.3 10 73.2 7 35 0.3 20 71.3 5.1 adsorption isotherm the profile obtained from the study of concentration at room temperature was used to obtain langmuir and freundlich adsorption isotherms by using well-known adsorption isotherm equations [17]. in both the cases, linear plots were obtained, which reveal the applicability of these isotherms on the ongoing adsorption process. figs. 11 and 12 exhibit langmuir and freundlich plots respectively for the adsorption n-hexane and n-heptane on feathers and different freundlich and langmuir constants derived from these plots are presented in table 3. to examine the progression of adsorption dimensionless constant, separation factor r was calculated by the following equation: …(2) where b and co values were derived from langmuir isotherm. the parameters indicate the shape of isotherm accordingly. table 3: relationship between separation factor and type of isotherm r value type of isotherm r > 1 r = 1 0<r < 1 unfavorable linear favorable the separation factor, as calculated from equation 2, indicates a favorable adsorption. values given in table 4 confirm the higher affinity of zeolite 5a to n-heptane as compared to nhexane. the adsorption data of n-hexane and n-heptane were described equally well by langmuir and by freundlich. the exponent (n) in the freundlich isotherm indicates favorable adsorption. these isotherms are shown in fig. 12. 0 0.2 0.4 0.6 0.8 1 0 50 100 150 c e /c o time (min) z=20cm z=10cm research octane number improvement of iraqi gasoline by adsorption of n -paraffins using zeolite molecular sieves 34 ijcpe vol.15 no.2 (june 2014) -available online at: www.iasj.net fig. 11: langmuir isotherm at room temperature for n-hexane and n-heptane adsorbing to zeolite 5a results show that the adsorption capacity for n-heptane on 5a zeolite was higher than that of n-hexane, which can be attributed to the higher molecular weight or higher carbon atoms. liu and shan [18] concluded also that the low-carbon-number normal paraffins occupying the microchannels of 5a zeolite can be partly replaced by normal paraffins with more carbon numbers. this is a basic phenomenon for adsorption that was reported by the earlier studies [1]. silva et al. [19] also concluded that zeolite 5a has more favorable nature of n-hexane compared to n-pentane. fig. 12: freundlich isotherm at room temperature for n-hexane and n-heptane adsorbing to zeolite 5a table 4: the separation factor component r type of isotherm n-c6 0.441939 favourable n-c7 0.601999 favourable table 5: constants for the isotherm models langmuir freundlich q 0 (g/gzeolite) b (l/g) q 0 (g/gzeolite) b (l/g) q 0 (g/gzeolite) b (l/g) n-c6 29.762 0.327 0.888 2.228 0.558 0.8770 n-c7 53.47 0.123 0.927 1.547 0.457 0.9087 kinetic study the pseudo first-order and secondorder kinetic models are the most popular models. in order to investigate the mechanism of sorption and potential rate controlling steps, the pseudo first and second order models were used. the first-order rate expression is: ln (qe −qt)=lnqe−k1t …(3) to investigate the fitness of pseudo first-order equation for n-hexane and n-heptane adsorption, ln(qe −qt) versus t is plotted as shown in fig. 13. the low r 2 value gives poor correlation of this model. the pseudo second order kinetic model is expressed as: t/qt = 1/k2qe 2 + t/qe …(4) if the pseudo second-order kinetics is applicable, the plot of t/qt versus t should give a linear relationship. the linearized form of this model is presented in fig. 14. fig. 13: pseudo first-order equation for nhexane and n-heptane adsorption 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0 0.5 1 1 /q e 1/ce langmuir c6 0 0.5 1 1.5 2 2.5 3 3.5 0 1 2 3 ln q e lnce freundlich c6 freundlich c7 nada sadoon ahmedzeki and arowa salah alddin mahdi -available online at: www.iasj.net ijcpe vol.15 no.2 (june 2014) 35 fig. 14: pseudo-second-order equation for nhexane and n-heptane adsorption, at temp.=40 c t.=40g andvolume=0.3liter the intra particle diffusion model is also investigated. thenparaffin uptake is assumed to vary almost proportionally with t 1/2 rather than with the contact time. the intra partical diffusion model is expressed in equation 5. qe =k t 1/2 +c …(5) where k is the intra particle diffusion rate constant (g/g min 1/2 ), c is the intercept (g/g) and a plot of qe versus t 1/2 gives a linear relationship as shown in fig. 15. fig. 15: intra-particle diffusion model for nhexane and n-heptane adsorption comparison of the three kinetic models revealed that the pseudo second order fits the experimental data quite well as high correlation coefficients of 0.999 and 0.998 are obtained. values of the kinetic models parameters are listed in table 6. silva and rodrigues [20] proposed that a macropore diffusion is controlling when they studied the sorption and diffusion of n-pentane on pellets of 5a (8mm). most of the previous literature performed this study in gas phase using a pressure swing adsorption (psa) which is highly recommended for further study. table 6: kinetic parameters for n-hexane and n-heptane adsorption kinetic models parameters compounds n-hexane n-heptane pseudo1storder k1 (min-1) 0.013 0.015 qe (g/gzeolite) 2.0422 3.2772 r2 0.555 0.895 pseudo-2nd order k2 (min-1) 0.01281 0.00822 qe (g/gzeolite) 13.6986 25.641 r2 0.998 0.999 intra-particle diffusion k (g/g.min0.5) 0.155 0.386 c (g/gzeolite) 11.00 19.86 r2 0.306 0.932 conclusions  increasing the agitation time and the amount of zeolite increased the removal efficiency of n-paraffins.  as a general trend, increasing the temperature had a negative effect on the reduction of nparaffins but the effect of temperature needed further evaluation at different temperatures.  the uptake of n-c7 on 5a zeolite was higher than n-pentane and nhexane favorably adsorbed on 5a zeolite. a desorption of nc5occursfrom the zeolite structure and replacement by other compounds of higher affinity; i.e. nc6 and n-c7. 0 5 10 15 20 25 30 0 5 10 15 q e t^0.5 research octane number improvement of iraqi gasoline by adsorption of n -paraffins using zeolite molecular sieves 36 ijcpe vol.15 no.2 (june 2014) -available online at: www.iasj.net  the removal efficiency increased with increasing bed height and decreasing feed flow rate using continuous mode investigations. furthermore, the bed would be saturated in less time for smaller bed height.  the results of this study indicated that the adsorption of n-c6and nc7from light naphtha followed the pseudo 2 nd order kinetic.  an increase in ron of 5.5 units was obtained using 40 g of zeolite in 300 ml light naphtha in a batch mode operation. on the other hand, an increase of 7 units was obtained after 30 min of a continuous operation using abed of 10 cm and 0.3 l/hr.  a favorable type of the adsorption for the present case study was as presented by a langmuir isotherm model for both n-hexane and nheptane adsorption on zeolite 5a. the calculated value of the separation factor confirmed the great tendency of zeolite 5a to nparaffins. acknowledgment the authors express their thanks to the petroleum and research development center for the financial support. further, the authors thank the arab company for detergents and chemicals for assistance in conducting the analysis. many thanks to mr. salah mahdi for his continuous help and guidance. references 1crittenden, b.d. and thomas, w.j., (1998)'adsorption technology and design'. 2johnson, j. (2004), 'uop sorbex family of technologies', in: meyers r.a. (editor in chief) handbook of petroleum refining processes, new york, mcgraw-hill. 3werner dabelstein, arno reglitzky, andrea schütze and klaus reders (2007),'automotive fuels', in ullmann's encyclopedia of industrialchemistrywileyvch, weinheim.doi:10.1002/14356007.a 16_719.pub2. 4liu, d. h. and hao, d. j., (1999), 'study on aromatization of hydrotreated coker gasoline for improving octane number'. china pet. process. petrochem. technol., 30, 4, pp. 21–24. 5li, y.a. and huang, g.h. (2000),' blending hydrotreated coker naphtha in ccr feedstock'. china pet. process. petrochem. technol., 31, 11, pp. 15–17. 6wang, x.l., (2000),'commercial test of hydro-treated delayed coking naphtha as reforming feedstock',china pet. process. petrochem. technol., 31, 2, pp.13– 16. 7zhou, m.p., (2001)'blending test of hydro treated coker naphtha in reforming plant and running analysis. catal. reforming lett., (3),pp. 26–32. 8cusher, n.a. (1997), in handbook of petroleum refining processes, ed. myers, r. a. (mcgraw–hill, new york), pp. 9.15 9sohn, s. w. (1997) in handbook of petroleum refining processes, ed. myers, r. a. (mcgraw–hill, new york), pp. 10.75 10maxwell, i.e. and stork, w.h.j., (1991), stud. surf. sci. catal. 58, pp.582. 11rabo, j. a., bezman, r.d., and. poutsma, m.l.(1978), acta phys. chem., 24,pp. 39. 12jeanneret, j.j. (1997) in handbook of petroleum refining processes, ed. myers, r. a. (mcgraw–hill, new york), pp. 2.27. 13moller a. guimaraes p., glser r. staudt r, 2009, uptake-curves http://en.wikipedia.org/wiki/digital_object_identifier http://dx.doi.org/10.1002%2f14356007.a16_719.pub2 http://dx.doi.org/10.1002%2f14356007.a16_719.pub2 nada sadoon ahmedzeki and arowa salah alddin mahdi -available online at: www.iasj.net ijcpe vol.15 no.2 (june 2014) 37 for the determination of diffusion coefficients and sorption equilibria for n-alkanes on zeolites, microporous and mesoporous materials 125, 23–29. 14wender, a., barreau, a., lefebvre, c., di lella, a., boutin, a., ungerer, p. and fuchs, a.h. (2007),' adsorption of n-alkanes in faujasite zeolites: molecular simulation study and experimental measurements', adsorption, 13, pp. 439–451, doi 10.1007/s10450-0079036-2. 15nadhir a. al-baghli* and kevin f. loughlin, binary and ternary adsorption of methane, ethane, and ethylene on titanosilicate ets-10 zeolite, j. chem. eng. data 2006, 51, 248-254. 16-ghaedi, m., taghavimoghadam, n., naderi, s., sahraei, r., daneshfar a. , 2013, comparison of removal of bromothymol blue from aqueous solution by multiwalled carbon nanotube and zn(oh)2 nanoparticles loaded on activated carbon: a thermodynamic study , journal of industrial and engineering chemistry 19 (5) ,pp. 1493-1500. 17foo k. and hameed b.,2010, insights into the modeling of adsorption isotherm systems, chemical engineering journal 156,2–10 18liu ji-chang and shen ben-xian (2009),' adsorption separation and use of normal and isohydrocarbons in hydrogenated coking gasoline', in energy and fuels, 23, 975–978. 19silva j, silva f, rodrigues a., 2000,separation of n/iso paraffins by psa separation and purification technology, 97–110. 20 silva j. and rodrigues a, 1997,sorption and diffusion of npentane in pellets of 5a zeolite,ind. eng. chem. res., 36, 493-500. iraqi journal of chemical and petroleum engineering vol.15 no.3 (september 2014) 27-35 issn: 1997-4884 microwave assisted demulsification of iraqi crude oil emulsions using tri-octyl methyl ammonium chloride (tomac) ionic liquid sawsan a.m. mohammed and watheq k. salih chemical engineering department – college of engineering – university of baghdad abstract in the present work, the efficiency of tri-octyl methyl ammonium chloride (tomac) ionic liquid was investigated as new and green demulsifier for three types of iraqi crude oil emulsions (nafut khana (nk), kirkuk and basrah). the separation efficiency was studied at room temperature and by using microwave heating technique. several batch experiments were done to specify the suitable conditions for the emulsification and demulsification which were specified as 45 minutes and 3000 rpm for crude oil emulsification while the ionic liquid doses were (500,300,150,50) ppm and the conditions of microwave heating were 1000 watt and 50 second as irradiation time. the results were very encouraging especially for nk and kirkuk crude oil emulsions where the separation efficiency was between (100%-95%) in both cases (by microwave heating and at room temperature demulsification). the separation percentages of basrah crude emulsion varied but as a general result, the efficiency was acceptable for high doses at the same time, while for low doses, the water removal ratio was not good as the previous one. keywords: demulsification, crude oil, w/o emulsion, microwave, tomac introduction crude oil is seldom produced alone because it is generally commingled with water. the water creates several problems and usually increases the unit cost of oil production. furthermore, sellable crude oil must comply with certain product specifications, including the amount of basic sediment and water (bs and w) and salt, which means that the produced water must be separated from the oil to meet crude specifications [1]. emulsions of crude oil and water can be encountered at many stages during drilling, producing, transporting and processing of crude oils and in many locations such as in hydrocarbon reservoirs, well bores, surface facilities, transportation systems and refineries. in each case, the presence and nature of emulsion can determine both the economic and technical success of industrial process concerned. a good knowledge of petroleum emulsions is necessary for controlling and improving processes at all stages. many studies have been carried out in the last 40 years and have led to a better understanding of these complex systems [2]. the formation of stable water-in-crude oil emulsions is frequently encountered during oil production, mainly due to high shear rates and zones of iraqi journal of chemical and petroleum engineering university of baghdad college of engineering microwave assisted demulsification of iraqi crude oil emulsions using tri-octyl methyl ammonium chloride (tomac) ionic liquid 28 ijcpe vol.15 no.3 (september 2014) -available online at: www.iasj.net turbulence that prevail at the wellhead in the choke valve. these complex and generally viscous systems significantly increase the technical problems related to oil-water separation in production surface facilities [3]. these emulsions can be very stable due to the presence of polar compounds such as asphaltenes and resins that play the role of “natural emulsifiers” and to the presence of low molecular weight fatty acids, naphthenic acids in addition to many types of fine solids (crystallized waxes, clays, scales, etc.).these materials help in the formation of resistant films at the crude oil/water interface [4]. because of the technical problems of water in oil emulsions, the emulsion breaking process which is known demulsification becomes very crucial and important in order to get oil with high quality and with minimum cost in all production and refinery stages. the water content must be less than 1% and typically 0.3% 0.5% because increasing water content in oil leads to increasing transportation costs [5, 6]. the complex nature of typical water-in-crude oil emulsions is one of the main difficulties for the development of adequate separation techniques in the petroleum industry. despite the huge efforts that have been made in the last 30 years for the development of reliable and efficient demulsification techniques, most water-in-crude oil emulsions cannot be broken in short times [7]. many separation techniques were used during past decades like mechanical, heating, electrical and chemical demulsification. every method has merits and defects. until now there is no method that could reach complete destabilization without a combination with another one. however, the chemical demulsification is an important method for w/o emulsion treating [8, 9]. due to more and more severe environmental constraints, there is now a strong need in the oil production to restrict the use of chemicals and to utilize safer formulations, less toxic but at least as efficient as classical demulsifiers [10]. many efforts have been performed to develop new strategies for achieving an efficient breaking of w/o emulsions in crude oil and, consequently, to remove water, salt and solids [11]. the efforts were focused on greener techniques to reach effective demulsification with minimum pollution and cost because creating a "green" brands demulsifiers is justified not only environmental, but also economic as a biodegradable agent does not require, or at least reduces the cost of cleanup and disposal of waste containing it. one of green technologies that has been focused on by recent studies and has provided interesting results for the treatment of crude oil emulsions is based on the application of microwave radiation. this kind of energy is effective, clean and economic especially it began to substitute the conventional ones in many scientific fields [12]. the principle of microwave-assisted demulsification processes is the change in the composition of the system through the use of specific compounds that have high dielectric properties, thus enhancing the absorption of radiation by the sample. moreover, these additives can be chosen to act in not only the heating system but also the mechanisms involved in the process. in this direction, ionic liquids (ils) have been widely used as additives in processes involving microwave heating [13]. ionic liquids (ils) have attracted many researchers in the areas including physics and chemistry because of their characteristics that are different from conventional molecular liquids and, today; ils have been one of interesting subjects of scientific study. they are sawsan a.m. mohammed and watheq k. salih -available online at: www.iasj.net ijcpe vol.15 no.3 (september 2014) 29 defined as specific class of molten salts with high dielectric properties, consisting of organic cations combined with anions of organic or inorganic nature. the chemical structure of ils allows many combinations of anions and cations, enabling one to obtain compounds with properties quite varied, which means that tailor-made ils can be produced for a given application. their boiling point is always less than 100 °c [14, 15]. in the present work, efforts were focused to test the efficiency of ionic liquids as new green demulsifiers with the combination of microwave heating technology .the research aims to assess the performance of these different materials as emulsion breaker for iraqi crude oil types for the first time. experimental work materials 1. crude oils: three types of iraqi crude oils were used. the physical properties of these oils are listed in table 1: table 1: physical properties of different iraqi crude oils property nk kirkuk basrah sp.gr. 0.8095 0.8509 0.8681 api 40 31 26 asph.(%wt) 0.08 1.29 2.1 kin.viscosity (cst) at 15 ° c 5.89 11.6 21.7 sulfur content % wt 0.58 2.33 3.33 ibp °c 37 46 43 2. sodium chloride was obtained from local markets 3. tomac ionic liquid of purity of 98% ,404.16 g/gmol m.wt, 550 cp viscosity , -20 ° c melting point ,100 ° c melting point was supplied by jandk chimica, china emulsion preparation the emulsion was prepared by adding different initial water ratios (30%, 15%, 8%) with (3% wt. nacl) to the different types of crude oil at room temperature. the emulsification was carried out by using a mixer at a speed of 3000 rpm for 45 minutes to get a stable w/o emulsion. the emulsions prepared in this way were stable for months without apparent phase separation [16]. demulsification several batch experiments were done to detect effects of some variables on emulsion breaking process and to assess the separation efficiency of tomac ionic liquid for the three types of iraqi crude oil emulsions in both cases with microwave heating and at room temperature. the prepared emulsion was heated by using microwave irradiation for 50 seconds and 1000 watts power. after heating, it was left at room temperature for 180 minutes and the total water removal percentage (w %) was calculated according to eq. 1 : …(1) where w %:= separation efficiency results and discussion 1. stability of prepared emulsion the stability of prepared emulsions was measured by two methods. the first test was aging test and the second test was droplets size distribution (dsd) measurement of droplets by using microscope (model n117m with fitted 5mp digital camera, beijing novel optics co., ltd/china). the two tests proved that prepared emulsions could be classified as tight emulsions where the emulsions did not show any clear separation over a period more than 6 months. table 2 shows dsd of emulsions. microwave assisted demulsification of iraqi crude oil emulsions using tri-octyl methyl ammonium chloride (tomac) ionic liquid 30 ijcpe vol.15 no.3 (september 2014) -available online at: www.iasj.net table 2: drop size distribution of emulsions crude oil type 30% emulsion droplet size (micron) 15% emulsion droplet size (micron) 8% emulsion droplet size (micron) nk 13-16 7-10 5.5-7 kirkuk 6.5 -9 5-7.45 5-6.45 basrah 6.-8 4.5 -6 3.5-5.5 2. water content effect the effect of initial volume fraction of internal phase (water) was studied for the three crude oil types containing different water content ratios using tomac. fig. 1 shows this effect. fig. 1: effect of water content on separation efficiency according to the figure above, the maximum emulsion resolution was obtained for emulsion with greater initial water content (30% vol.). it is important to mention here that because dielectric properties are influenced by medium composition, it is necessary to understand the relationship between these properties and the emulsion wc. this is especially important in demulsification processes, where wc variations are expected to occur. besides, emulsion wc can also influence the coalescence efficiency during the demulsification process, leading to a reduced distance between droplets in the sample. this distance can be severely narrowed with the increase of the volume of the aqueous phase in the emulsion, raising the probability of collision between the droplets. 3. asphatene content effect the asphaltene content effect on emulsion breaking process for three types of crude oil emulsions is shown in fig. 2 fig. 2: effect of asphaltene content on separation efficiency fig. 2 showed the separation efficiency is (99 % vol.) for kirkuk emulsion with 1.29%wt. asphaltene content, and it is about 44 %vol. for basrah emulsion which has 2.1% wt. asphaltene when the dose is 50 ppm and 180 minutes settling time while the separation percentage was 100% for nk emulsion with less than 50 ppm and 10 minutes. asphaltene content may play a role over the interfacial properties of the emulsion and over stability. the asphaltene molecules aggregate with each other or with wax molecules and migrate to water /oil interface and form a layer surrounding the water droplet. this elastic layer prevents and inhibits the coalescence process. when the asphaltene content increases, the thickness of this layer will increase because of the increase in the aggregate rate of its molecules and its precipitation at w/o interface. 4. dose effect fig. 3 shows the effect of demulsifier dose on the separation efficiency for basrah crude oil emulsion. settling time ( min) w at er s ep ar at io n ( % v o l) 0 15 30 45 60 75 90 105 120 135 150 165 180 195 0 10 20 30 40 50 60 70 80 90 100 microwave power= 1000 watts radiation time = 50 sec ionic liquid type= tomac dosage = 150 ppm basrah crude oil 30% water content 15% water content 8% water content aspaltene content ( % wt) w a te r se p a ra ti o n r a ti o ( % v o l. ) 0 0.25 0.5 0.75 1 1.25 1.5 1.75 2 2.25 0 10 20 30 40 50 60 70 80 90 100 nk crude oil kirkuk crude oil basrah crude oil water content= 15% salinity = 3% nacl microwave power= 1000 watts irradiation time= 50 sec. demulsifier type= tomac dose= 50 ppm seperation time= 180 min sawsan a.m. mohammed and watheq k. salih -available online at: www.iasj.net ijcpe vol.15 no.3 (september 2014) 31 fig. 3: dose effect on separation efficiency for basrah crude oil emulsion as it is seen in fig. 3, the maximum separation ratio was obtained at the maximum dose of tomac and this behavior is the same for the three initial water contents. demulsification efficiency increases as the concentration of the demulsifier increases up to a certain value. at this concentration, the demulsifier molecules perform a complete coverage of the water/oil interface, dragging the asphaltenes away from the interface. as a result, the protecting film present around the dispersed water droplets thins and then it ruptures and coalescence eventuates. 5. salt content effect different salt contents were examined to study its effect on the water separation efficiency. the maximum chosen concentration was 30000 ppm because it is the concentration of most oilfield emulsions. fig. 4 shows the effect of salt concentration on demulsification efficiency. fig. 4: salt content effect on separation efficiency it is noticed that the demulsification efficiency decreased when salt content increased. for 0 % salt content, water separation percentage reached to 90% but this percentage decreased with increasing salt concentration to reach 79% at 3% salt content. this reduction of the separation efficiency with the increase of the salt content (or ultimately of the ionic strength) could be explained by the reduction of the power applied by the microwave device. in this way, the microwave interaction with the polar species in the interfacial film is expected to be poorer, resulting in weaker perturbations of this interface and then in reduced coalescence rates tomac separation assessment a. ionic liquid efficiency combined with microwave irradiation the performance of ammonium based ionic liquid is examined as crude oil demulsifier. tomac ionic liquid was tested as demulsifier for the three crude oil types as following: nk crude oil emulsion showed no need for heating because it was completely separated at room temperature. tomac performance with kirkuk crude oil emulsion was also very great. for the three water contents (8%, 15 %, and 30%), the separation percentage is between 99% to 100%. figs. 5, 6 and 7 clarify the tomac efficiency to demulsify this emulsion. fig. 5: tomac efficiency with 8% water content kirkuk crude oil emulsion dose ( ppm) s e p e ra ti o n w a te r (% ) 0 50 100 150 200 250 300 350 400 450 500 550 0 10 20 30 40 50 60 70 80 90 100 microwave power= 1000 watt radiation time = 50 sec basrah crude oil 30 % 15% 8 % salt concentration (% ) w a te r s e p a ra ti o n ( % v o l) 0 0.5 1 1.5 2 2.5 3 3.5 70 75 80 85 90 95 100 microwave power= 1000 watts radiation time= 50 sec demulsifier type= tomac demulsifier dose = 150 ppm total time = 180 min settling time (min) w at er s ep ar at io n ( % ) 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 water content =8 % salinity= 3% nacl microwave power= 1000 w irradiation time = 50 sec kirkuk crude oil 500 ppm 300 ppm 150 ppm 50 ppm 0 ppm microwave assisted demulsification of iraqi crude oil emulsions using tri-octyl methyl ammonium chloride (tomac) ionic liquid 32 ijcpe vol.15 no.3 (september 2014) -available online at: www.iasj.net fig. 6: tomac efficiency with 15% water content kirkuk crude oil emulsion fig. 7: tomac efficiency with 30% water content kirkuk crude oil emulsion figures 5, 6 and 7 show that the emulsion breaking process was effective for all doses. but the differences were in settling time where it varied from less than 5 minutes to 180 minutes as maximum for three types of kirkuk emulsions. basrah, emulsions with different water initial water contents were examined by using microwave and tomac ionic liquid. the water separation efficiency was very good for high doses. the results of the three water contents were acceptable as shown in figs. 8, 9 and 10. fig. 8: tomac performance for 8 % basrah crude oil emulsion fig. 9: tomac performance for 15 % basrah crude oil emulsion fig. 10: tomac performance for 30 % basrah crude oil emulsion the results in the figures clarify the performance of tomac for basrah emulsions where the results are acceptable. the percentages for high doses are very good and they reached 98% water separation for 500 ppm while separation percentages began to decrease with low dose. in fig. 10, the maximum water removal percentage was (98%) for 500 ppm whereas the ratio was (69%) for 50 ppm after 180 minutes settling time. from fig. 9, the results of emulsion breaking were between (86%) for 500 ppm and (44%) for 50 ppm. in fig. 8, the same behavior was detected. at 500 ppm demulsifier dose, the separation percentage was (80%) while with 50 ppm, the percentage did not exceed (30%). the effectiveness and the high activity of tomac can be attributed to chloride anion which exists in tomac ionic liquid which has a main and important role in demulsification process. this anion has effective ability to dissolve asphaltene ˗ resin network aggregates by interaction with settling time (min) w at er s ep ar at io n ( % ) 0 15 30 45 60 75 90 105 120 135 150 165 180 0 10 20 30 40 50 60 70 80 90 100 water content =15 % salinity= 3% nacl microwave power=1000 w irradiation time = 50 sec kirkuk crude oil 500 p p m 300 p p m 150 p p m 50 p p m 0 p p m settling time (min) w at er s ep ar at io n ( % v ol ) 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 water content =30% salinity= 3% nacl microwave power =1000 watt radiation time =50 sec kirkuk crude oil 500 p p m 300 p p m 150 p p m 50 p p m 0 p p m settling time (min) w at er s ep ar at io n ( % v o l) 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 demulsifer type = tomac water content =8 % salinity= 3% nacl microwave power =1000 watt radiation time =50 sec basrah crude oil 500 ppm 300 ppm 150 ppm 50 ppm 0 ppm settling time (min) w at er s ep ar at io n ( % ) 0 20 40 60 80 100 120 140 160 180 0 15 30 45 60 75 90 water content =15 % salinity= 3% nacl tomac 1000 watt 50 sec irradiation time basrah crude oil 500 p p m 300 p p m 150 p p m 50 p p m 0 p p m settling time (min) w at er s ep ar at io n ( % ) 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 water content =30% salinity = 3% nacl m icrowave p ower =1000 watt radiation time =50 sec tom ac demulsifier basrah crude oil 500 ppm 300 ppm 150 ppm 50 ppm 0 ppm sawsan a.m. mohammed and watheq k. salih -available online at: www.iasj.net ijcpe vol.15 no.3 (september 2014) 33 molecules of this network. this interaction makes the coalescence process of droplets faster. b. tomac efficiency at room temperature one of the important characteristics for successful demulsifier is its ability to work at wide temperate range. in the previous sections, the range of temperature was about (50 -70) °c when the microwave heating was used. in this part, the performance of ionic liquids was investigated at room temperature which was about (28-33) °c. for nk crude oil emulsion, a complete separation (100%) was achieved for the three water content ratios, but the time at which this separation was reached was different where it was 5, 15, and 30 minutes for (8%,15% and 30% ), respectively. the used tomac dose was 50 ppm. fig. 11 shows that the efficiency is excellent for 30% kirkuk crude oil emulsion for all tomac doses ranging between 99% ˗ 95 %. the same behavior was observed for 15% and 8% water content emulsions as shown in figures 12 and 13, but in general the separation percentages were lower than the previous ratio. fig. 11: tomac performance for 30%kirkuk crude oil emulsion at room temperature whereas, the behavior was different for basrah crude oil emulsions when they were tested at room temperature. the performance varied according to the initial water content and tomac doses. in general, the demulsification process at high water content and high doses was very good as shown in fig. 14, but the separation percentages at low water contents and small doses were not high enough to be considered as it is shown in figures 15 and 16. fig. 12: tomac performance for 15%kirkuk crude oil emulsion at room temperature fig. 13: tomac performance for 8 %kirkuk crude oil emulsion at room temperature fig. 14: tomac performance for 30% basrah crude oil emulsion at room temperature fig. 15: tomac performance for 15% basrah crude oil emulsion at room temperature settling time ( min) w at er s ep ar at io n ra ti o (% v ol ) 0 25 50 75 100 125 150 175 200 225 250 275 300 0 10 20 30 40 50 60 70 80 90 100 water content = 30% salinity = 3% nacl room temerturate= 30 c kirkuk crude oil 500 p p m 300 p p m 150 p p m 50 p p m 0 p p m settling time ( min) w at er s ep ar at io n ra ti o (% v ol ) 0 25 50 75 100 125 150 175 200 225 250 275 300 0 10 20 30 40 50 60 70 80 90 100 water content = 15% salinity = 3% nacl room temerturate= 30 c kirkuk crude oil 500 p p m 300 p p m 150 p p m 50 p p m 0 p p m settling time ( min) w at er s ep ar at io n ra ti o (% v ol ) 0 25 50 75 100 125 150 175 200 225 250 275 300 0 10 20 30 40 50 60 70 80 90 100 water content = 8 % salinity = 3% nacl room temerturate= 30 c kirkuk crude oil 500 ppm 300 ppm 150 ppm 50 ppm 0 ppm settling time (min) w at er s ep ar at io n ( % ) 0 35 70 105 140 175 210 245 280 315 0 15 30 45 60 75 90 water content =30% salinity= 3% nacl room temperature= 30 c basrah crude oil 500 p p m 300 p p m 150 p p m 50 p p m 0 p p m settling time (min) w at er s ep er at io n ( % ) 0 25 50 75 100 125 150 175 200 225 250 275 300 0 10 20 30 40 50 60 70 80 90 100 water content =15 % salinity= 3% nacl room temperture=30 c basrah crude oil 500 p p m 300 p p m 150 p p m 50 p p m 0 p p m microwave assisted demulsification of iraqi crude oil emulsions using tri-octyl methyl ammonium chloride (tomac) ionic liquid 34 ijcpe vol.15 no.3 (september 2014) -available online at: www.iasj.net fig. 16: tomac performance for 8 % basrah crude oil emulsion at room temperature from figures 14, 15 and 16, it is also noticed that the separation required more than 180 minutes. the separation process at room temperature needs about 300 minutes to reach 98% for 500 ppm dose and 30 % initial water content emulsion. at the same time, the behavior is alike for 15% and 8 % initial water content emulsions with lower separation ratios. this might be attributed to the difference in crude oil composition like asphaltenes and wax content and also to the higher viscosity and density for basrah crude oil which is very clear from tomac behavior with this type of emulsion. the time required to achieve the same separation efficiency is twice that needed for kirkuk crude oil emulsion which has density, viscosity and asphaltene content less than the former emulsion. conclusions 1. ionic liquids (tomac) showed high efficiency as green demulsifier for different grades of iraqi crude oil emulsions. 2. for nk emulsion, the experiments showed complete separation at room temperature with dose less than 50 ppm and there is no need to use heating. 3. for kirkuk crude oil emulsions, the water separation percentages were about (100%-99%) for all doses when the microwave heating was used. 4. at room temperature , the separation ratios for kirkuk emulsions were between (100% ˗ 95%) for all doses with different settling times but the maximum settling time was recorded for lower dose 50 ppm. 5. for basrah emulsions, the maximum separation was recorded for 30% initial water content and 500 ppm dose with using mw. 6. at room temperature, the separation ratios varied for different doses and initial water ratios but the maximum separation was recorded for 30% initial water content. the settling time was longer than that obtained with mw heating. references 1fanchi r. john (2006), "petroleum engineering handbook: general engineering " vol. 1, society of petroleum engineers, richardson, usa p.533 2langevin d., poteau s., hénaut i., and argillier j.f. ( 2004), " crude oil emulsion properties and their application to heavy oil transportation", oil and gas science and technology rev. ifp, vol. 59, no. 5, pp. 511-521 3 schramm l. laurer (1992) "emulsions: fundementals and applications in petroleum industry", american chemical scosity ,usa 4dalmazzone c.,noïk c .and clausse c.(2009)," application of dsc for emulsified system characterization", oil and gas science and technology – rev. ifp, vol. 64, no. 5, pp. 543-555 5zhukov arkadiy and zaripov salavat (2012)," new green oilfield agents, green chemistry – environmentally benign approaches", dr. mazaahir kidwai (ed.), isbn: 978-953-51-0334-9, in tech, rijeka, croatia p124 6 hirasaki george j., miller clarence a., raney olina g., poindexter michael k., nguyen settling time (min) w at er s ep er at io n ( % ) 0 25 50 75 100 125 150 175 200 225 250 275 300 0 10 20 30 40 50 60 70 80 90 100 water content =8 % salinity= 3% nacl room temperuture=30 c basrah crude oil 500 p p m 300 p p m 150 p p m 50 p p m 0 p p m sawsan a.m. mohammed and watheq k. salih -available online at: www.iasj.net ijcpe vol.15 no.3 (september 2014) 35 duy t. and hera john (2011), "separation of produced emulsions from surfactant enhanced oil recovery processes", energy fuels, vol. 25, no.2, pp. 555–561 7fortuny m. , oliveira c. b. z., melo r. l. f. v., nele m., coutinho r. c. c., and santos a. f., (2007),"effect of salinity, temperature, water content and ph on the microwave demulsification of crude oil emulsion",fuel,vol.24,pp. 3610– 3615 8wu j., xu y., dabros t., and hamza h. (2003),"effect of demulsifier properties on destabilization of water-in-oil emulsion",energy and fuels, vol.17, pp.1554-1559 9 al-sabagh a. m., noor el-din m. r., morsi r. e., elsabee m. z. (2008), " demulsification efficiency of some novel styrene/maleic anhydride ester copolymers", journal of applied polymer science, vol. 108,pp. 2301–2311 10dalmazzone c.and noïk c. (2001) , "development of new "green" demulsifiers for crude production", society of petroleum engineers inc,spe international symposium on oilfield chemistry held in houston, texas, 13–16 february 11 antes g. f., pereira j. s. f., diehl l.o., pereira l. s. f., boeck p., guimarães r. c. l., guarnieri r. a., ferreira b.m. s., santos m. de f. p. dos, folettob e. l. and flores e. m. m. (2013)," sediment removal from crude oil emulsion using microwave radiation", j. braz. chem. soc., vol. 24, no. 8, pp. 1287-1294 12grundas s. (2011),"adavances in induction and microwave heating of mineral and organic materials" in-tech , rijeka, croatia 13lemos r. c b., da silva e. a. b., dos santos a., guimaraes r. c. l., ferreira b. m. s., guarnieri r. a., dariva c., franceschi e., santos a. f., and fortuny m. (2010), " demulsification of water-in-crude oil emulsions using ionic liquids and microwaveirradiation",energy fuels, vol.24,pp.4439–4444 14 kadokawa j-ichi (2013)," ioni liquids-new aspects for the future", in-tech, rijeka, croatia 15huddleston j. g., visser a.e., reichert w. m., willuer h. d., broker g. a. and rogers r. d. (2001), " characterization and comparison of hydrophilic and hydrophobic room temperature ionic liquids incorporating the imidazolium cation", green chem., vol. 3, no.4, pp. 156–164 16salih watheq k. (2013), "microwave assisted demulsification of crude oil emulsions using organic additives and ionic liquids", m.sc. thesis, chem. eng. depart, college of engineering, university of baghdad. iraqi journal of chemical and petroleum engineering vol.18 no.2 (june 2017) 69 81 issn: 1997-4884 waste water treatment by liquid-solid adsorption using calcined sand-clay mixture adsorbent raghad f. almilly and mohanned h. hasan chemical engineering department, college of engineering, university of baghdad email: rfkalm@yahoo.com and mhh1970m@yahoo.com abstract effluent from incompetent wastewater treatment plants (wwtps) contains a great variety of pollutants so support water treatments are essential. the present work studies the removal of phosphate species from aqueous solutions by adsorption on to spherical calcined sand -clay mixture (cscm) used a natural, local and low-cost adsorbent. batch experiments were performed to estimate removal efficiency of phosphate. the adsorption experiments were carried out as function of ph, dose of adsorbent, initial concentration, temperature and time of adsorption. the efficient removal was accomplished for ph between 10 and 12. the experimental results also showed that the removal of phosphate by (cscm) was rapid (the % removal 98.9%, 92%, 90%, 89% in 60 min) when the initial phosphate concentrations were at 5, 10, 15, 20 mg/l, respectively at optimum ph 10-12 and optimum dose was 5 gm/200ml. the adsorption process is time dependent. thermodynamic studies showed that phosphate adsorption was exothermic. the effect of temperature range of 15-30 °c has been investigated. the results indicated that the temperature significantly affected phosphate adsorption on (cscm) adsorbent. langmuir and freundlich isotherms models indicated that both isotherms were proper to describe the adsorption characteristics of (cscm), with langmuir being more fit. adsorption capacity of phosphate had equal to 0.835 mg phosphorous/g adsorbent. the study reveal that calcined sand-clay mixture is an excellent low cost material for phosphate removal in wastewater treatment process . key words: adsorption, wastewater, phosphate, calcined sand-clay mixture. introduction environmental problem has a serious consequences on public health due to inefficient treatment of domestic, municipal and industrial wastewater. nutrient discharged in the surface water and ground water bear a great deal of responsibility on water bloom and eutrophication that adversely affects on surface water [1]. the concentrations of phosphorus between 3 and 15 mg/l mostly brought together from domestic and industrial wastewaters [2]. according to the requirement of american state environmental agencies and the u.s. environmental protection agency (epa) the total phosphorus effluent concentrations from dischargers must university of baghdad college of engineering iraqi journal of chemical and petroleum engineering mailto:rfkalm@yahoo.com mailto:mhh1970m@yahoo.com waste water treatment by liquid-solid adsorption using calcined sand-clay mixture adsorbent 70 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net be as far as 0.05 mg/l to deal with water quality problems [3] . biological, chemical, or combined biological and chemical processes are common methods for phosphorus removal performance. a specific group of polyphosphate accumulating microorganisms play a great deal of consuming excessive phosphorus as intracellular storage through biological treatment, and then phosphorus is removed from the liquid by sludge wasting. chemical phosphorus technique is established to precipitate phosphate as form of sparingly soluble metal phosphate complexes by adding salts of multivalent metal ions (e.g. fecl3, fe2(so4)3, al2(so4)3, or ca(oh)2). biological and chemical processes are similar in target to take out only soluble orthophosphates or transform those forms in the influent into ortho-p during the treatment process then in to solids phase by subsequent solid and liquid separations. once p effluent level observed within permitted limits indicate both the effectiveness of chemical and/or biological p treatment processes in achieving goals as well as efficient final solid and liquid separation [4]. adsorption has been tested as an alternative to conventional method for phosphate removal in wastewater treatment for a long time. for several reasons, inorganic adsorbents are offered to use as promising alternative [5]. adsorption process was chosen especially for some advantages such as less production of sludge and easy operation, but it has not been applied widely since the suspended solids contained in the feed water accumulate in and clog the adsorbent bed and most adsorbents cannot be reused [6]. various adsorbents were improved for phosphate removal such as alum sludge [7], red mud [8], fly ash [9], calcite [10], dolomite mineral [11], clay soil [12], bentonite clay [13], the purposes of this study were to determine the following: (1) the feasibility of using calcined sandclay mixture (cscm) to adsorb phosphate; and (2) the optimal conditions of using calcined sand-clay mixture for phosphorus removal. material and method adsorbate synthetic phosphate stock solutions were prepared in the laboratory by dissolving an amount of anhydrous potassium dihydrogen phosphate kh2po4 (0.2195 g) in 1 liter distilled water. further dilution was conducted on the stock solution to get the desired concentrations of the experimental solutions using distilled water. to determine phosphate concentration the vanadomolybdo phosphoric acid colometric method was followed with a uv–vis spectrophotometer and measured at 470 nm according to [14]. adsorption media (adsorbent preparation) sand and clay materials have been brought from the sea of najaf region and mixed at different volume percent ages to form spherical particles about 10 mm in diameter by hand. after that they have been dried and then calcined at 800 c to prevent their dissolution in the water. chemical properties the chemical analysis of the adsorption media was achieved using (xrf) in the university of baghdad / college of science /department of geological survey and mining. the results of the composition of each material used in this study are presented as given in table 1. http://www.iasj.net/ raghad f. almilly and mohanned h. hasan -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 71 table 1: chemical composition of adsorbent constituent clay wt.% sand wt.% sio2 27.90 27.03 al2o3 7.251 0.6517 fe2o3 6.734 0.6288 mgo 3.116 0.486 cao 13.44 32.43 k2o 1.13 0.0516 physical properties the physical properties of the adsorbent was analyzed in the oil research and development centerministry of oil. the tests conducted were: particle surface area, using bet method, pore volume and bulk density, according to astm b527. the results of surface area measurements are listed as given in table 2. table 2: physical properties of calcined sandclay mixture surface area, m 2 /g pore volume cm 3 /g bulk density g/cm 3 20.33 0 .0303 0.9799 adsorption experiment batch experiments were implemented to achieve the equilibrium data. artificial wastewater was prepared from kh2po4 at different concentrations 5, 10, 15 and 20 mg/l. adsorbent ranging in weight 5, 10, 15 and 20 g with 10 mm in diameter were placed in individual 200 ml distilled water of 500 ml glass bottle capacity. the bottles were placed at fixed positions in a shaker. the bottles were left for a suitable time ranging from 15 min to 240 min to allow adsorption to reach equilibrium conditions. the shaker speed controller was at constant speed of 100 rpm. after shaking, the mixture was filtered through a 0.45 μm filter. vanadate-molybdate reagent of 10 ml and 5 ml of distilled water were added to 35 ml of filtered sample. after 15 min the mixed solution was analyzed for phosphate concentration by a uv–vis spectrophotometer at the detection wavelength of 470 nm according to [14] the adsorbed amount, qt was calculated from equation 1 qt=(co–ce)v/m …(1) where qt is the amount adsorbed per unit gram of adsorbent (mg/g) in t time, co the initial concentration (mg/l), ce the equilibrium concentration (mg/l), v the volume of solution (200 ml), and m the weight of the adsorbent (g). the following equation was used to determine the percentage removal of phosphate at any time: 100(%)    i i c cec r …(2) where: ci, ce mg/l is the initial and equilibrium concentration of each phosphate. the shaker provided with a digital temperature sensor and speed controller. the experiments were conducted at 15, 20 and 30 °c and the shaker speed controller was at constant speed of 100 rpm. two types of isotherm batches, were conducted, one of controlled experiments at ph 4, 7 and the other are uncontrolled experiments ph 11. buffer solutions, 0.1m of hcl and 0.1m naoh were added drop wise to the water to control the ph. in these runs the ph was controlled at 4, 7. buffer solutions were not added for the runs conducted without a ph control. results and discussion effect of initial phosphate concentration and contact time the effect of the initial concentrations (5-20 mg/l) on the adsorption by (cscm) at constant adsorbent weight, 5 g is as shown in figure 1. a fast initial sorption capacity of phosphate at the beginning 30 min was noticed and, http://www.iasj.net/ waste water treatment by liquid-solid adsorption using calcined sand-clay mixture adsorbent 72 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net next, the sorption capacity was further increased but with a much slower rate till it reached equilibrium in about 60 min. the equilibrium adsorption increased from 0.188 to 0.375 mg/g with increase in the initial phosphate concentration from 5-20 mg/l. upon investigating the effect of contact time, rapid removal of p was observed in the first 30 minutes, with 89.4%, p removal in this period at 5 mg/l as shown in figure 2. fig. 1: effect of initial concentration and contact time for the adsorption of phosphate on sand clay adsorbent weight=5 gm; ph 11, temperature =20 ◦c fig. 2: effect of initial concentration and contact time on percentage removal of phosphate contact time on percentage removal of phosphate at constant adsorbent dose 5 g and ph10-12, temperature =20 ◦c effect of sorbent dosage the effect of sorbent dosage on percentage removal of phosphate is as shown in figure 3. it was observed that the percentage removal increased from 98.9% to 100% with increase in adsorbent dose from 5 to 20 g at 5 mg/l, increase from 92% to 99% at 10 mg/l, increase from 90% to 96% at 15 mg/l, and increase from 89% to 92.7% at 20 mg/l. with a dose of 5 g (cscm) /200 ml of simulated solution resulting in a 95%, 92%, 90%, 89% removal in p concentration at 5, 10, 15, 20 mg/l, respectively. above this dosage of adsorbent, any increase in p removal is small. a dosing rate of 5 g was therefore recommended. 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 0 50 100 150 200 250 300 so rp ti o n c a p a ci ty , q t( m g /g ) time (min) 5mg/l 10mg/l 15 mg/l 20 mg/l 0 20 40 60 80 100 120 0 50 100 150 200 250 300 r e m v a l % time (min) 5 mg/l 10 mg/l 15 mg/l 20 mg/l http://www.iasj.net/ raghad f. almilly and mohanned h. hasan -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 73 fig. 3: effect of amount of adsorbent for the removal on phosphate using calcined sand clay mixture: temperature =20 ◦c, ph 11; time =60 min effect of ph value experiments were conducted under varying ph between 4 and 12. the ph of the solution was adjusted with 0.1 mol/l hcl or 0.1 mol/l naoh for only acidic and neutral solution. there is no need for controlling ph under usual case, since the adsorption process was spontaneously occurred in basic solution once the solution was added to adsorbent. the experiments were achieved at 5, 10, 15, 20 g each adsorbent dose with 5, 10, 15, 20 mg/l initial concentrations, respectively. figure 4 removal efficiency increased from 16% to 53.4% to 98.9% when ph increased from 4 to 7 to 10 respectively. solution ph is an important controlling parameter in determining the dominant phosphorus removal mechanism, as well as the existing ionic species in solution are responsible for a given mechanism [15]. aqueous phosphate exists in four forms depending on the ph of a given solution. these are: 1. phosphate ion (po4 3), which predominates in strongly basic conditions; 2. hydrogen phosphate ion (hpo4 2), which is the dominant form at weakly basic conditions; 3. dihydrogen phosphate ion (h2po4 ), which predominates in weakly acidic conditions; and 4. trihydrogen phosphate (h3po4) which is the main form at strongly acidic conditions. (pka=2.2) …(3) (pka=7.2) …(4) (pka=12.3) …(5) the logarithmic constant, pka, is given as …(6) a smaller pka value (i.e., a larger ka value). a strong acid does not change ph and is therefore vital to understanding the possible removal mechanisms associated with phosphate. in sorption studies involving the uptake of phosphorus on to calcined sand-clay mixture (cscm), it was found that the highest phosphorus removal occurred at ph 10-12. there was three different forms of phosphate, e.g., , 88 90 92 94 96 98 100 102 0 5 10 15 20 25 r e m o v a l % adsorbent dose (gm) 5mg/l 10mg/l 15mg/l 20mg/l http://www.iasj.net/ waste water treatment by liquid-solid adsorption using calcined sand-clay mixture adsorbent 74 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net and in the solution as described in equations 3-5. generally, governing species in the ph region between 4 and 10, and with notice that species were governed in slightly alkaline conditions, but species governed in slightly acidic conditions. dominated over species between ph 10 ph 12, while species governed at ph higher than 12.5, [16]. there are several factors that controls the phosphate adsorption: phosphate speciation in solution, phzpc (zero point charge) of the adsorbent and the affinity of phosphate ions towards the adsorbent [17]. the ph at which the net surface charge zero on the adsorbent is called phzpc. the surface charge of the adsorbent become negative when ph is less than phzpc value, therefor a higher repulsion between the binding sites and phosphate ions resulting lower phosphate uptake, while the surface become a net positive charge when the ph is greater than phzpc that improve coulombic attraction between the sites and the phosphate ions leading an increase in phosphate adsorption. the solution begins to donate more protons than hydroxide groups, when the ph is less than pka, that cause the sorbent surface positively charged attracting negatively charged species [18]. in this study, the higher removal of phosphates at ph 10-12 (less than pka value of 12.3) indicates that the species involved in adsorption were affected by ph. maximum phosphate sorption took place when it was higher than phzpc of the (cscm) surface, and less pka value 12.3 of , the conditions that facilitated (cscm) surface to be positively charged. this observations have revealed that was the key species involved in range of adsorption process. the phenomenon may be explained another mechanism via precipitation. hydrolysis of metal oxides generate metal cation and hydroxyl anion ( ) as the following equation. …(7) ( ) …(8) fig. 4: effect of ph value on the phosphate removal efficiency at different concentration, dose = 5 g and equilibrium time of 60 min 0 20 40 60 80 100 120 ph4 ph7 ph12 5 gm 10 gm 15 gm 20 gm % r e m o v a l http://www.iasj.net/ raghad f. almilly and mohanned h. hasan -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 75 the cationic species participate in phosphate up taking through electrostatic interaction, while the anionic species used inner sphere ligand exchange mechanism. likewise phosphate metal precipitation took place as the equation given below [19]: …(9) the presence of calcium oxides and silicates oxides in relatively large quantities as shown in table 2.1 may support the precipitation mechanism. thus phosphorus-removal pathway in the (cscm ) surface are adsorption on to the (cscm) surface by precipitation of metallic phosphate salts. the orthophosphates which is particularly form of phosphorus, was indicated that able to absorbed by clay minerals and various organic soils fraction in the soil matrix and chemically precipitate with ca (at neutral to alkaline ph values) [20]. effect of temperature the effect of temperature on the phosphate adsorption rate (qe) was also examined over temperature range of 1530 °c. figure 5 shows the effect of temperature on the adsorption rate. it can be seen that the phosphate adsorption rate on calcined sand-clay mixture (cscm) decreases with increasing temperature from 15 to 30 °c. the maximum adsorption rate was 0.63 mg/g at 15 °c decreased to 0.47 mg/g at 30 °c. this means that the adsorption of phosphate ions was improved at lower temperatures. the sorption of phosphate is exothermic. a similar observation was reported for removal of phosphate using dolomite mineral [21]. thus the amount of adsorption decreased with increasing temperature. in contrast, the sorption of phosphate was endothermic used alginate-calcium carbonate composite beads [22]. it is noticed that removal efficiency decreased from 95% to 79%, 89% to 70%, 78% to 66%, 75% to 60% when temperature raised from 15 °c to 30 °c, at varying concentrations 5, 10, 15, 20 mg/l, respectively. as shown in figure 6. fig. 5: effect of the temperature on the sorption capacity ph=10-12; amount adsorbent=5 gm; contact time =30 min; at different concentrations 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 285 290 295 300 305 so rp ti o n c a p a si ty m g /g temperature k http://www.iasj.net/ waste water treatment by liquid-solid adsorption using calcined sand-clay mixture adsorbent 76 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net fig. 6: effect of the temperature on the phosphate removal ph=10-12; amount adsorbent=5 gm; contact time =30 min; at different concentrations isotherm equations for singlesolute adsorption two-parameter isotherms the well-known equations proposed by langmuir (1918) and freundlich (1906) are typical representatives of the group of two-parameter isotherms. they belong to the most frequently used isotherm equations. the langmuir isotherm has the form: …(10) a linear regression is also possible because all two-parameter equations can be linearized. for langmuir isotherm, different types of linearization are possible as follows: = …(11) the langmuir equation is valid for monolayer sorption onto the surface and energetic homogeneity of the adsorption sites. on the other hand, the langmuir isotherm equation was also found to be applicable in cases where the underlying assumptions obviously not fulfilled. and b are langmuir parameters related to maximum adsorption capacity (mg of solute per g of adsorbent) and free energy of adsorption, respectively. is the concentration of solute at equilibrium (mg/l) and is the amount of solute adsorbed per unit weight of adsorbent at equilibrium (mg of adsorbate per g of adsorbent). it is possible to estimate and b from both intercept and slope, respectively through linear plot of the experimental data of versus as illustrated in figure 7 and tabulated in table 3. the higher values of the correlation coefficient ( ) for both isotherms indicates that obviously best fit to experimental data. it is possible to explain good fitness in terms of surface nature of the adsorbent and affinities to towards phosphate concerning of various mineralogical forms exist in the adsorbent. the freundlich isotherm is given by: …(12) where k and n are the isotherm parameters. the freundlich isotherm can describe neither the linear range at very low concentrations nor the saturation effect at very high concentrations. by contrast, the medium concentration range is often 0 10 20 30 40 50 60 70 80 90 100 285 290 295 300 305 r e m o v a l % temperature k 5 mg/l 10 mg/l 15mg/l 20mg/l http://www.iasj.net/ raghad f. almilly and mohanned h. hasan -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 77 very well represented. freundlich isotherm is a common used to describe the characterization of adsorption from aqueous solutions. it has been applied for the prediction of multi solute adsorption, the equilibrium relationship in the most kinetic and breakthrough curve models. it is convenient to convert freundlich isotherm into the logarithmic form as: …(13) where k describe the strength of adsorption. high k value means high the adsorbent loading. the exponent n value indicate the degree of isotherm curvature as well as the energetic heterogeneity of the adsorbent surface. the isotherm becomes the more concave when the lower the n value is. if the concentration has a value of 1 in the respective unit, the loading equals the value of k. in experiments the exponent n is possible take any value. in practice, however, mostly n values lower than 1 are found. with n = 1, the isotherm becomes linear. freundlich isotherms are characterized as favorable with n < 1 that display relative high adsorbent loadings at low concentrations, whereas are recognized as unfavorable with n > 1. the value of k and n that represent intercept and slope, respectively be estimated from the linearization equation of 13 through taking logarithm of both sides equation 12 as illustrated in figure 8 and tabulated in table 3 .as shown in figures 7-8 the ( ) value for langmuir model (0.9975) is slightly higher than of the freundlich model (0.9821) which may denote the control of monolayer adsorption process over intra-molecular interactions among the adsorbed phosphate [19]. from both figures it can be seen that langmuir model showed a better fit of the data than the freundlich model. fig. 7: langmuir adsorption isotherm for phosphate on calcined sand clay mixture: temperature=20 ◦c; ph 10-12; adsorbent dose =5 gm; time =30 min table 3: isotherm constants for phosphate adsorption onto sand clay mixture parameters temperature, °c 15 20 30 langmuir qm mg/g 0.616 0.67 0.631 b (l/mg) 1.85 .678 0.312 r 2 0.9908 .9978 0.9907 freundlich n 2.73 2.099 1.8 kf(mgl -1/n g -1 l 1/n ) 0.344 0.25 0.157 r 2 0.9771 0.9821 0.995 y = 2.201x + 1.4888 r² = 0.9975 0 1 2 3 4 5 6 7 0 0.5 1 1.5 2 2.5 1 /q e 1/ce http://www.iasj.net/ waste water treatment by liquid-solid adsorption using calcined sand-clay mixture adsorbent 78 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net fig. 8: freundlich adsorption isotherm for phosphate on calcined sand clay mixture: temperature =20 ◦c; ph 10-12; adsorbent dose =5 gm; time =30 min the mathematical expression of langmuir isotherm of dimensionless constant which is commonly known as separation factor (rl) can be defined as equation 14: …(14) in this regard rl value can be considered as a preferential indicator of the adsorption. in deeper clarification, there are four values of the rl, for favorable adsorption (0 < rl <1), for unfavorable (rl > 1), for irreversible (rl = 0) and for linear (rl = 1). values of rl were proved that calcined sand clay mixture is favorable for adsorption of phosphate under conditions studied as shown in table 5 where the values of rl were in the range of 0-1at all temperatures studied. table 4: the maximum adsorption capacity of phosphate on different adsorbents adsorbent material qm mg/g references modified bentonite 34.48 tang yan-kui et al., 2006 burned kaolin 0.61 majd i.abdul wahab et al., 2011 calcined sand clay mixture 0.63 the present work table 5. the parameter rl indicates the shape of isotherm as function of temperature. temperature 15, °c nominal concentration mg/l actual concentration mg/l rl 5 5.18 0.094 10 11.65 0.044 15 16.6 0.0315 20 21 0.025 temperature 20, °c 4.76 0.236 11.61 0.112 16.56 0.081 20.88 0.065 temperature 30, °c 5.1 0.385 10.66 0.231 15.33 0.172 19.9 0.138 thermodynamic of phosphate adsorption onto calcined sand clay mixture (cscm) the thermodynamic factors of phosphate adsorption onto sand-clay mixture including changes in standard enthalpy (δh°), standard entropy (δs°) were estimated by using the following van’t hoff equation [21], …(15) the gibbs free energy (δg°) was evaluated by using equation 16: y = 0.4764x 0.599 r² = 0.9821 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1 lo g q e log ce http://www.iasj.net/ raghad f. almilly and mohanned h. hasan -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 79 δg°=-rtlnk …(16) where r is gas constant (8.314 j.mol1.k-1), k is the equilibrium constant at temperature t can be calculated from the ratio of amount adsorbed on solid at equilibrium ci and the equilibrium concentration of phosphate ce (mg/l) as expression: k = ci/ce. the negative values of  g were (2.63, -2.06, -1.021 kj/mol) at 288, 293, 303 k, respectively as shown in table 6 which indicate spontaneous process by (cscm) as an adsorbent. values of  h and  s were calculated from the slope and intercept of the van’t hoff linear plot of log k versus 1/t as shown in figure 9. the negative values of  h (-33.8 kj/mol) as shown in table 5 prove the exothermic nature of adsorption. the negative values of  s (-108.25 j/mol.k) reflect lower randomness at the solid/solution interface during the adsorption of phosphate. thermodynamic factors were reported  h (-5.85 kj/mol),  s (-10.17 j/mol.k) for the adsorption of phosphate on dolomite [21]. fig. 9: vant’t hoff plot for the adsorption of phosphate onto calcined sand clay mixture adsorbent (ph=10-12) table 6: thermodynamic parameters for the adsorption of at various temperatures onto calcined sand clay mixture temp. (ºc) kj/mol kj/mol j/mol.k 15 3 -2.63 -33.8 -108.25 20 2.33 -2.06 30 1.5 -1.021 conclusions the results of the present work can provide a process for developing a low-cost technology based on adsorption by calcined sand-clay mixture for phosphate removal from wastewater. the following points can be concluded from the present study: calcined sand-clay mixture (cscm) removes phosphate from aqueous solution rapidly. phosphate may be removed by adsorption and/or by precipitation of calcium phosphate. phosphate adsorption by (cscm) increased with the increase in ph and reached spontaneously at the maximum adsorption in the ph range of 10-12. as the initial concentration of phosphate increases 5 to 20 mg/l, the amount of adsorbed phosphate on y = 1766.4x 5.6539 r² = 0.9998 0 0.1 0.2 0.3 0.4 0.5 0.6 0.00325 0.0033 0.00335 0.0034 0.00345 0.0035 lo g k c 1/t k-1 logkc 3 4 po  g h  s http://www.iasj.net/ waste water treatment by liquid-solid adsorption using calcined sand-clay mixture adsorbent 80 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net the adsorbent increases. as the temperature increases 15-30 ◦c the adsorption rate decreases over the studied adsorbent which indicates that the adsorption of phosphate was favoured at lower temperature, since the adsorption of phosphate is exothermic. equilibrium isotherm adsorption data obey both langmuir and freundlich models with slightly fit by langmuir. the maximum adsorption capacity of (cscm) is 0.835 mg/g p. (cscm) can be used as an effective, low-cost, available and locally adsorbent for the removal of phosphate. nomenclature b langmuir isotherm constant l/mg cscm calcined sand clay mixture c concentration of adsorbate in feed mg/l ce equilibrium phosphate concentration mg/l co initial concentration of phosphate ions mg/l cf final concentration of phosphate ions mg/l kf freundlich isotherm constant mgl-1/ng-1l1/n n freundlich intensity parameter qm the maximum amount of adsorbate per unit weight of adsorbent mg/g qe concentration of adsorbate in solid phase at equilibrium mg/g qt concentration of adsorbate in solid phase at time t mg/g rl separation factor r 2 coefficient of determination rpm rotation per minute references 1. de-bashan l. e., y. bashan, 2004, “recent advances in removing phosphorus from wastewater and its future use as fertilizer”, water res. 38, 4222–4246. 2. tran n., p. drogui, j.f. blais, g. mercier, 2012, “phosphorus removal from spiked municipal wastewater using either electrochemical coagulation or chemical coagulation as tertiary treatment”. sep. purif. technol. 95, 16–25. 3. ragsdale d., 2007, ”advanced wastewater treatment to achieve low concentration of phosphorus”, epa. 4. liu l., m. bracken, d.s. smith, d. houweling, j.b. neethling, h.d. stensel, s. murthy, a. pramanik, a. z. gu, 2011 ”phosphorus fractionation in various tertiary effluentsinsights into and implications for advanced phosphorus removal, nutrient recovery and management”, 1192– 1204. 5. ozacar m. 2003. “adsorption of phosphate from aqueous solution onto alunite”. chemosphere 51:321327. 6. kuzawa k., jung y. j., kiso y., yamada t., nagai m., lee t. g. 2006. “phosphate removal and recovery with a synthetic hydrotalcite as an adsorbent”. chemosphere 62:45-52. 7. nawar n., m. e. ahmad, w. m. el said, s. m. n. moalla, 2015, ”adsorptive removal of phosphorous from wastewater using drinking water treatmentalum sludge (dwt-as) as low cost adsorbent”, american journal of chemistry and application, 2(6): 79-85. 8. al-fatlawi a.h. and neamah m.m., 2015, ”batch experiment and adsorption isotherm of phosphate removal by using drinking water treatment sludge and red mud” ijarset, 2, 557-571. http://www.iasj.net/ raghad f. almilly and mohanned h. hasan -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 81 9. ragheb s.m., 2013, ”phosphate removal from aqueous solution using slag and fly ash”, housing and building national research center, 9, 270–275. 10. karageoriou k., m. paschalis, georgios n. anastassakis, 2007, ”removal of phosphate species frome solution by adsorption on to calcite used as natural adsorbent” hazard mater. 139, 447–452. 11. yuan x., wentang x., juan an, jianguo y., xuejiao z., and wenqiang y., 2015, ”kinetic and thermodynamic studies on the phosphate adsorption removal by dolomite mineral”, journal of chemistry, 2015, 1-8. 12. mallikarjan. s. d. and shashikant. r. mise, 2013, ”a batch study of phosphate adsorption characteristics on clay soil” ijret, 338-342. 13. farhan a. m., a. s sameen. 2014 “kinetic study of adsorption rhodamine 6g dye from aqueous solutions using bentonite clay”, american journal of environmental engineering, 4 (1): 11-17. 14. lenore s., amold e., andrew d., 1999 ,”standard methods for the examination of water and wastewater“ twentieth ed., washington:, american public health association. 15. lee, s. h., vigneswarn, s., moon, h., 1997 ”adsorption of phosphate in saturated slag media columns. seperation and purification technology, 12 (2), 109-118. 16. liana a. r., l. maria, p. s. getano, 2010 ”adsorption kinetic, thermodynamic and desorption studies of phosphate on to hydrous niobium oxide prepared by the reverse microemulsion method, adsorption 16., 173-181. 17. krishnan k. a., a. haridas, 2008 ”removal of phosphate from aqueous solutions and sewage using natural and surface modified coir pith, journal of hazardous mater., 152, 527-535. 18. abir e., 2009 ”phosphate removal from aqueous solution by adsorption on to ammoniumfunctionalized mesoporus silica m.sc. thesis quebec ,department of soil and agriculture engineering university of laral. 19. rout p. r., p. bhunia, r. r. dash, 2014 ”modling isotherms, kinetics and understanding the mechanism of phosphate adsorption on to a solid waste: ground burnt patties, journal of environmental chemical engineering, 2, 13311342. 20. hamdan r. and d. mara, 2013 ”study of in-filter phosphours removal mechanisms in an aerated blast furnace slag” ijret, 2 (8), 130-136. 21. xiaoli y., w.xia, j.an ,j.yin, x.zhou, and w.yang, 2015 ”kinetic and thermodynamic studies on the phosphate adsorption removal by dolomite mineral” hindawi journal of chemistry 2015, 8p. 22. zahid m., s. nasir, n. jamil, a. sheikh and a. akram, 2015 ”adsorption studies of phosphate ions on alginate-calciume carbonate composite beads”, african journal of environmental science and technology, 9 (3) 275-281. http://www.iasj.net/ iraqi journal of chemical and petroleum engineering vol.18 no.3 (september 2017) 13 29 issn: 1997-4884 enhancing the lifting capacity of drilling fluids in vertical oil wells amel habeeb assi petroleum engineering dept. / university of baghdad abstract of the many functions that are performed by the drilling fluid, the most important is to transport cuttings from the bit up the annulus to the surface. various drilling fluid have been widely used in the oil industry to improve lifting capacity. in this study, three mud type have been used which they are, oil base mud, x-anthan polymer and a mixture of cmc and bentonite ,by using carrying capacity index calculation (cci) , the xanthan gave good values of cci than other studied drilling fluid. by using sifferman chart and field data from well in south of iraq and api equation to find cutting concentration in the annulus, the results showed that the used of thick mud increase the lifting capacity and decrease volumetric drill cuttings in the annulus but the using thin mud lead to decrease lifting capacity and increase volumetric drill cuttings in the annulus .the results show that the mud viscosity and flow rate have important role in hole cleaning. also, the effect of annulus velocity and flow pattern on cutting transport ratio is studied by using field data. the effect of cutting size and od of drill pipe is also studied. cutting size is one of the parameters that influence the hole cleaning; large size cutting makes the hole cleaning more difficult. the reducing of annular size of hole by increasing the od of drill pipe lead to increasing the annular velocity. key words: lifting capacity, cutting transport,drilling fluid, viscosity. introduction this work contain studying of many factors that have been affect on lifting capacity of drilling fluid ,like the effect of mud type and the value of flow rate on lifting capacity, also the effect of flow patterns on the lifting capacity. efficient transportation of cuttings is a vital factor for a good drilling program cutting transport in annulus is a complex problem that is affected by numerous parameters. the ability of a circulating drilling fluid to transport rock fragments out of a well bore. a solid particle in the hole is acted on by four factors: gravity, viscos drag, impact and bouncy, the problems associated with inefficient hole cleaning include: decreased bit life and slow penetration resulting from regarding of drill cuttings and increasing in annular density and, in turn, annular hydrostatic pressure of mud .the increased hydrostatic pressure of mud may cause the fracture of an exposed weak formation resulting in lost circulation darley[1]. carrying capacity is an essential function of a drilling fluid, carrying capacity is determined principally by the annular velocity, hole angle and flow profile of the university of baghdad college of engineering iraqi journal of chemical and petroleum engineering enhancing the lifting capacity of drilling fluids in vertical oil wells 14 ijcpe vol.18 no.3 (sep. 2017) -available online at: www.iasj.net drilling fluid. for the effective drilling cuttings generated by the drill bit must be removed immediately. the drilling mud carries the drill cuttings up the hole and to the surface, to be separated from the mud. the carrying of lifting capacity of mud is depend on several parameters including fluid density ,viscosity, type of flow ,annulus size, annular speed ,particle shape and particle diameter. other factors such as pipe rotation, pipe eccentricity, also have some influence on the carrying capacity of the mud. api13a[2]. cutting transport one of the primary functions of a drilling fluid is to bring the drilled cuttings to the surface. inadequate hole cleaning can lead to a number of problems, including hole fill, packing off, stuck pipe, and excessive hydrostatic pressure. the ability of a drilling fluid to lift cuttings is affected by many factors, and there is no universally accepted theory which can account for all observed phenomena. some of the parameters which affect cuttings transport are the fluids density and viscosity, annular size and eccentricity, annular velocity and flow regime, pipe rotation, cuttings density, and the size and shape of the cuttings. if the cuttings are of irregular shape (and most are) they are subjected to a torque caused by the shearing of the mud walker [3]. if the drill pipe is rotating, a centrifugal effect causes the cuttings to move towards the outer wall of the annulus. the process is further complicated because the viscosity of non-newtonian fluids varies according to the shear rate, and therefore the velocity of the cutting changes with radial position. finally, transport rates are strongly dependent on cutting size and shape young [4]. cutting slip velocity a rock particle falling through mud tends to settle out at constant velocity (zero acceleration) described as a slip velocity. a cutting, traveling up the annulus, experiences a positive upward force due to the drilling fluid velocity, density and viscosity, and a negative downward force due to gravity. the rate at which a cutting falls is known as its “slip velocity”. several studies have enabled the following generalizations to be made: 1. the most important factors controlling adequate cuttings transport are annular velocity and rheological properties. 2. annular velocities of 50 ft/min provide adequate cuttings transport in typical muds. 3. cuttings transport efficiency increases as fluid velocity increases. 4. the slippage of cuttings as they are transported induces shear thinning of the mud around the cutting reducing the expected transport efficiency. 5. cutting size and mud density have a moderate influence on cuttings transport. those who have observed a solids tracer emerging over the shale shaker will realize the large spread of “cuttings” that occurs. therefore, any calculated estimation of slip velocity will only be an approximation. the reason for this “spread” of solids is the particles ability to be carried by the drilling fluid. it is a function of its position in the mud stream and the size of the particle o‟brien [5]. cuttings will travel up the annulus more efficiently if they travel flat and horizontally. if the cutting turns on its edge, it will slip more easily. smaller cuttings are more prone to do this. rotation of the drill pipe will result in a helical motion of the fluid, which will aid transport for those cuttings nearest the pipe api rp 13i,[6]. the rheological properties of the drilling fluid will affect cuttings transport, in as much as they affect the flow profile. amel habeeb assi -available online at: www.iasj.net ijcpe vol.18 no.3 (sep. 2017) 15 lowering the “n” value or an increase in the yp/pv ratio will generally flatten the flow profile and increase carrying capacity barnes [7]. effect of major drilling parameters on cuttings transport summary of the influence of major drilling parameters on cuttings transport in wells are presented as follows: 1rotation speed: as pipe rotate, it reduces eccentricity and also alters the velocity distribution. significant positive effect, in small annulus the effect of rotation is more dominate than a large annulus. rotation is also an effective element in removing small cuttings; a rotate pipe drags the cutting from low side of annuals to the high side. as shown in fig. (1). 2mud type –three type of mud has been studied to show the effect of mud type on cutting transport. those three mud type are fresh water bentonite, gel bentonite mud, and polymer mud. those three mud type are really used in the field to drill three wells in south of iraq, hole size: 12.25″ hole, depth: from 650m to 2022 m. the laboratory measurements for each mud type are given in table (1), table (2), and table (3), and as shown in fig.2.it's clear that the polymer mud type is the best mud because is give good lifting capacity compared with the other studied mud type. also the gel bentonite mud type gave good lifting capacity. 3mud weight –the high mud density can transport the cutting through the annulus faster than the low mud density. for the effect of fluid density on cutting transport, three fluid densities were considered. these are 9.32, 11.66 and 12.91ppg. at the high annular velocity the curve of high mud density and low mud density are close to each other but at the low annular velocities the high mud density performs better than low mud density. in other words low mud density coupled with high annular velocity can give good hole cleaning and as shown in fig. (3) 4mud rheology-moderate positive or negative effect depending on the cuttings size, pipe rotation, hole inclination, and annular eccentricity and as shown in fig.(4), increasing the plastic viscosity is not a desirable means of increasing the hole-cleaning ability of a mud. in fact, the increase in pressure drop down the drill string, caused by an increase in pv, would reduce the available flow rate and tend to offset any increase in lifting ability. in general, high plastic viscosity is never desirable and should be maintained as low as practical. 5cutting sizeis one of the parameters that influences the hole cleaning, for this analysis the small, medium and large sized cuttings were considered for the analysis. hopkin [8]. enhancing the lifting capacity of drilling fluids in vertical oil wells 16 ijcpe vol.18 no.3 (sep. 2017) -available online at: www.iasj.net fig. 1, the effect of rpm values on cutting transport ratio fig. 2, the effect of mud type on cutting transport ratio fig. 3, the effect of mud weight on cutting transport ratio amel habeeb assi -available online at: www.iasj.net ijcpe vol.18 no.3 (sep. 2017) 17 fig. 4, the effect of mud viscosity on cutting transport ratio table 1, laboratory measurements for fresh bentonite mud ᶲ600 ᶲ300 ᶲ200 ᶲ100 ᶲ6 ᶲ3 37 29 20 17 15 12 funnel vis. 52 sec/qt mud weight 1.09 sp.gr pv 8 cp gel 10 sec 12 lb./100ft^2 gel 10 min 18 lb./100ft^2 yp 21 lb/100ft^2 table 2, laboratory measurements for gelbentonite mud ᶲ600 ᶲ300 ᶲ200 ᶲ100 ᶲ6 ᶲ3 52 49 29 22 13 10 funnel vis. 57 sec/qt mud weight 1.12 sp.gr pv 13 cp gel 10 sec 10 lb./100ft^2 gel 10 min 15 lb./100ft^2 yp 26 lb./100ft^2 table 3, laboratory measurements for polymer mud ᶲ600 ᶲ300 ᶲ200 ᶲ100 ᶲ6 ᶲ3 72 55 33 27 19 14 funnel vis. 61 sec/qt mud weight 1.3 sp.gr pv 17 cp gel 10 sec 15 lb./100ft^2 gel 10 min 25 lb./100ft^2 yp 31 lb/100ft^2 carrying capacity index (cci) only three drilling parameters are controllable to enhance moving drilled solids from the well bore: annular velocity (av), mud weight mw), and mud viscosity. examining cuttings discarded from shale shakers in vertical and near-vertical wells during a 10-year period, it was learned that sharp edges on the cuttings resulted when the product of those three parameters was about 400,000 or enhancing the lifting capacity of drilling fluids in vertical oil wells 18 ijcpe vol.18 no.3 (sep. 2017) -available online at: www.iasj.net higher. av was measured in ft. /min, mw in lb. /gal, and viscosity (the consistency, k, in the power law model) in cp. when the product of these three parameters was around 200,000, the cuttings were well rounded, indicating grinding during the transport up the well bore. when the product of these parameters was 100,000 or less, the cuttings were small, almost grain sized. thus, the term carrying capacity index (cci) was created by dividing the product of these three parameters by 400,000: as shown in eq. (1) … (1) robinson [9]. to ensure good hole cleaning, cci should be 1 or greater. if the calculation shows that the cci is too low for adequate cleaning, the equation can be rearranged (assuming cci=1) to predict the change in consistency, k, required bringing most of the cuttings to the surface: … (2) since mud reports still describe the rheology of the drilling fluid in terms of the bingham plastic model, a method is needed to readily convert k into pv and yp. the chart given in fig.5 serves well for this purpose. in a vertical hole, laminar flow with low pv and elevated yp or low n-value and high k-value (from the power law model) will produce a flat viscosity profile and efficiently carry cuttings out of the hole walker [3]. fig. 5, conversion of bingham plastic yield point to power law. bourgoyne et all[18] experimental work three of mud samples have been studied in this study to find which of them can give good hole cleaning, those muds are: (bentonit and cmc), (x-anthan polymer), and oil base mud (direct emulsion) bellow the properties of each sample and the uses of each one: 1cmc: carboxymethyl cellulose is a cellulose derivative obtained by chemically modification the natural cellulose. cmc is one of the most important water soluble polymers with many advantages that other amel habeeb assi -available online at: www.iasj.net ijcpe vol.18 no.3 (sep. 2017) 19 natural or synthetic glues don‟t have. cmc is tasteless, smells, nontoxic nonflammable and easily dissolved in water to become transport, viscos solution amoco[10]. cmc solution has good properties of thickening, adhering, emulsifying and stabilizing membrane forming .the solution of cmc can be mixed with dissolvable animal glues, glycerin, arabic gum, and dissolvable starch. cmc can protect the shaft wall and prevent mud loss, thus enhance recovery efficiency; three type of cmc (lvcmc, mv-cmc and hv-cmc) has the following characteristic: -excellent water retention even at low concentration and excellent rheological property. -excellent thickening effect and good resistance to salt mud and temperature change m-i llc [11]. the first mud consists from 4.2% of red bentonite and the hv.cmc additives begin from 03% to 2% and 450 cc of water. 2x-anthan polymer: the natural polymers, which perform by thickening water, are essentially non-charged and are less sensitive to their environment. these materials increase the viscosity of water due to their molecular size, shape, and ability to absorb water. . xanthan polymer is a viscosifier and affords very little fluid loss .xanthan gum can build viscosity in fresh, sea and salt water without the assistance of other additives. uniquely the molecular forms a rigid rod like structure in solution, this gives very high viscosity or gels at low shear rates. consequently, xanthan polymer gives excellent suspension properties that cannot be matched by other polymers at equivalent. this polymer also increase the carrying capacity of mud to enhance the hole cleaning api rp13d [12]. the second mud consists from 450 cc water and xanthan gum begin from 0.2% to1.3%. 3oil base mud: oil base mud system is one in which the continuous phase of a drilling fluid is oil. when water is added as the discontinuous phase then it is called an invert emulsion. these fluids are particularly useful in drilling production zones, shales and other water sensitive formations, as clays don‟t hydrate or swell in oil. they are also useful in drilling high angle horizontal wells because of their superior lubricating properties and low friction when values between the steel and formation which result in reduced torque and drag api rp 13b2[13],. the third mud consist from 3.3% red bentonite and 450 cc of water and gas oil additives begin from 5% to 25% the rheological properties of the three studied drilling fluid is measured in the lab, by using viscometer model 800 viscometer to read the shear velocity to calculate the values of pv and yp by using eq.3 and eq.4 respectively: … (3) … (4) the density of each drilling fluid is measured by using mud balance. by using the carrying capacity index (cci) equation to find which the drilling fluid that will give the value of cci greater than 1, the experimental work and the results is shown in table (4), table (5) and table (6). the xanthan gave good values of cci comparing with the mixture of (bentonite and cmc) and oil base mud. the oil base mud gave the lowest value of cci. it's clear that there is an increase in the yp/pv ratio in x-anthan enhancing the lifting capacity of drilling fluids in vertical oil wells 20 ijcpe vol.18 no.3 (sep. 2017) -available online at: www.iasj.net mud and mixture of (bentonite and cmc), but for oil base mud there is decrease in the yp/pv ratio. the increase in the yp/pv ratio will generally flatten the flow profile and increase carrying capacity or carrying capacity index while the decrease in yp/pv ratio lead to bad hole cleaning. the values of yb is low in oil base mud compared with x-anthan polymer and and mixture of (bentonite and cmc), also the values of k is low in oil base mud compared with x-anthan polymer and mixture (bentonite and cmc), also the density of oil base mud is low compared with x-anthan polymer and mixture (bentonite and cmc). all that parameters lead to decrease the value of cci in oil base mud. the cci is used in this research to choose the best drilling fluid from between the studied drilling fluids because its equation treat with the three drilling-fluid controllable parameters to enhance moving drilled solids from the well bore to lift it up. those three drilling-fluid controllable parameters are: annular velocity (av), mud weight mw), and mud viscosity. the annular velocity was 110 ft. /min. table 4, the experimental work and the results for mixture of (bentonite and cmc) bent. gm. water cc cmc gm. ᶲ600 ᶲ300 pv cp yb lb/100ft 2 yp/pv k from fig. 5 cci from eq.1 20 450 1.5 24 13 11 2 0.1818 65 0.1716 20 450 3 41 27 14 13 0.9286 200 0.528 20 450 4.5 49 33 16 17 1.0625 310 0.8184 20 450 6 58 41 17 24 1.4118 620 1.6368 20 450 7.5 67 48 19 29 1.5263 1010 2.6664 20 450 9 79 57 22 35 1.5909 1180 3.1152 table 5, the experimental work and the results for x-anthan polymer water volum cc xanthan ᶲ600 ᶲ300 pv cp yb lb/100ft 2 yp/pv k from fig 5 cci from eq.1 450 1 12.5 7.5 5 2.5 0.5 42 0.100485 450 2 14 9 5 4 0.8 81 0.193793 450 3 24 18.5 5.5 13 2.3636 810 1.937925 450 4 53 38 15 23 1.5333 950 2.272875 450 5 75 51 24 27 1.125 988 2.36379 450 6 89 64 25 39 1.56 1550 3.708375 amel habeeb assi -available online at: www.iasj.net ijcpe vol.18 no.3 (sep. 2017) 21 table 6, the experimental work and the results for oil base mud water cc bent.gm gas oil cc gas oil by volume% ᶲ600 ᶲ300 pv cp yb lb/100ft 2 yp/pv k from fig 5 cci from eq.1 ρgas oil gm /cc 450 15 22.5 5 20 13 7 6 0.8571 90 0.2042 8.25 450 15 45 10 25 16 9 7 0.7778 110 0.245 8.1 450 15 67.59 15 28 17.5 10.5 7 0.6667 160 0.3432 7.8 450 15 90 20 44 26 18 8 0.4444 310 0.6539 7.67 450 15 112.5 25 51 31.5 19.5 12 0.6154 388 0.7992 7.49 cutting concentration calculation in the annulus in vertical hole sifferman published transport ratios collected with annular flow model made with a twelve inches outer steel diameter and various diameter inner tubes. the model was about 100 feet long. he defined transport ratio as in eq. (4). his transport ratio is the seen to be the solid's velocity expressed as a fraction of the annular velocity. … (5) bourgoyne et al.[18]. where: t.r. =transport ratio, vf =mud annular velocity, fpm,vs= solids free settling velocity, fpm the annular fluid velocity is calculated by using eq. 6 … (6) bourgoyne et al [18] sifferman identified three types of mud for the publication of his transport ratios: thick, intermediate, and thin; and water has been added sifferman[14]. the fan dial reading and gels of his muds are given in table (7). his chart was modified by sample gives transport ratios versus inverse mud annular velocity for his mud type and as shown in fig. (6). table 7, sifferman mud types type ᶲ600 ᶲ300 ᶲ200 ᶲ100 ᶲ6 ᶲ3 gel 10 sec gel 10 min thick 69 53 45 36 23 20 13 29 intermediate 49 35 30 25 15 13 13 22 thin 24 16 13 10 3 3 2 3 enhancing the lifting capacity of drilling fluids in vertical oil wells 22 ijcpe vol.18 no.3 (sep. 2017) -available online at: www.iasj.net fig. 6, sifferman transport bourgoyne et al api used the following steady state equation for the volumetric drill cuttings in the annulus: … (7) where: rop=average drilling rate, ft./hr. vfc=average new drill cutting concentration; vol% dbit =bit diameter; inch. q=circulating rate; gpm field application field data from well in south of iraq used to show the effect of mud viscosity on the cutting concentration, hole size: 12.25″ hole, depth: (520 – 1568) m. by using sifferman chart to find drill cutting transport ratio and api equation, eq. (6) to find the volumetric drill cuttings in the annulus, the used mud type to drill the 12.25" hole section in this well was intermediate consistency, table 8 and table 9 show the properties of the used mud ,the fluid obey power law model. table (7) shows the sifferman mud types and table (8) shows laboratory measurement for the field mud, the fluid is obey yield –power low depending on the average absolute percentage error (aape) method. by comparing the values of shear rate for the field mud table (8) and in and the values of shear rate for the intermediate type in table (7), the tow values are nearly the same values. so the field mud is considered to be intermediate consistency. two cases of mud type also have been studied: the first case assumed that the drilling is done by using thick mud; the second case assumed that the drilling is done by using thin mud. the results showed that the used of thick mud increase the lifting capacity and decrease volumetric drill cuttings in the annulus but the using thin mud lead to decrease lifting capacity and increase volumetric drill cuttings in the annulus and as given in table (10). in fact the density and volume of cutting in the annulus cannot control it but the volumetric drill cuttings in the annulus can be under control. beck[14]. amel habeeb assi -available online at: www.iasj.net ijcpe vol.18 no.3 (sep. 2017) 23 table 8, the laboratory measurement for the field mud ᶲ600 ᶲ300 ᶲ200 ᶲ100 ᶲ6 ᶲ3 47 34 29 24 14 11 funnel vis. 55 sec/qt mud weight 1.18 sp.gr pv 13 gel 10 sec 10 lb/100ft^2 gel 10 min 25 lb/100ft^2 yp 21 table 9, the materials that the drilling fluid consist from them additives function concentration lb./bbl. bentonite to enhance viscosity, gel, and filter cake 10 -15 soda ash to control ph & total hardness because of ca++ ion & maintain ph between 9 – 10 0.5 – 1.0 caustic soda to control ph & total hardness because of mg++ ion & maintain ph between 9 – 10 0.5 – 1.0 polysalht api fluid loss controller 4 6 duovis rheology 0.5 – 0.75 kcl 3-5% weight material and shale/clay inhibitor. 10 15 asphasol supreme extra inhibitor for reactive shale/clay to avoid tight hole condition & bit balling issue. 2 3 m-i pac-ul fluid loss control 0.5 2 lime source for alkalinity 0.5 -1 drilzone surfactant 0.5 0.7 caco3-f/med weighting and bridging agent 30 table 10, the volumetric drill cuttings calculation in the annulus when q=117 gpm vf fpm from eq.5 1/vf lifting capacity from fig.6 vfc (api) from eq.6 mud type dbit ,in 12.25 25.13 0.039 0.68 0.093 intermediate(real) rop,ft/hr 73 25.13 0.039 0.97 0.065 thick(assumed) q,gpm 117 25.13 0.039 0.29 0.22 thin (assumed) oddp 6 table 11, the volumetric drill cuttings calculation in the annulus when q=175gpm vf f/min from eq.5 1/vf lifting capacity from fig.6 vfc (api) from eq.6 mud ype dbit ,in 12.25 37.58 0.026 0.76 0.055 intermediet(real) rop,ft/hr 73 37.58 0.026 1 0.042 thick(assumed) q,gpm 175 37.58 0.026 0.52 0.081 thin (assumed) oddp 6 enhancing the lifting capacity of drilling fluids in vertical oil wells 24 ijcpe vol.18 no.3 (sep. 2017) -available online at: www.iasj.net table (12) shows the effect of the decreasing in the value of flow rate on the volume of cutting in the annulus and lifting capacity. in the case of using thin mud the value of the lifting capacity decrease to the half compared with original assumed value, and the volume of cutting in the annulus has increased to the forth compared with original assumed value, in other words the drilling with those conditions can be cause more problems. in the case of intermediate mud the value of lifting capacity also decrease from 68% to 57%,and. in the case of using thick mud, there is not difference between both lifting capacities values 97% and 91% because the high mud viscosity help to lift cutting out of the annulus until in the case of low value of flow rate. table 12, the volumetric drill cuttings calculation in the annulus when q=88gpm vf from eq.5 1/vf lifting capacity from fig.6 vfc (api) from eq.6 mud ype dbit ,in 12.25 18.68 0.053 0.57 0.15 intermediet(real) rop,ft/hr 73 18.68 0.053 0.91 0.09 thick(assumed) q,gpm 88 18.68 0.053 0.1 0.85 thin (assumed) oddp 6 table (13) summarize the effect of flow rate values on the lifting capacity at different mud type table 13, the relation between flow rate (q) and lifting capacity, (t.r.) q g/min t.r. thin mud t.r. intermediate mud t.r. thick mud 88 0.1 0.57 0.91 117 0.29 0.68 0.97 175 0.52 0.76 1 field application analysis by using eq. 7 and eq.8 the values of slips velocities are calculated. the laminar mode shows the lowest slip velocity than turbulent mode so the flow pattern in the second interval assumed to be laminar flow. the value of lifting capacity of the second interval is better than the value of lifting capacity of the first interval and as shown in fig. 7. cutting size is one of the parameters that influence the hole cleaning; in general large size cutting makes the hole cleaning more difficult. for the first interval the cutting size was 3.5" and for the second interval the cutting size was 2.5", that different in cutting size for both interval effects on lifting capacity. based on the studied system ,at the first interval the fluid viscosity was 10 cp while for the second interval the fluid viscosity was 16 cp ,that increasing in the fluid viscosity enhancing the value of transport ratio and transform the flow pattern from turbulent to laminar. the fluid viscosity is increased by using hv amel habeeb assi -available online at: www.iasj.net ijcpe vol.18 no.3 (sep. 2017) 25 cmc. in other words the laminar flow gave good hole cleaning than turbulent flow for this well .the driller use more than one value of the density to get good value of lifting capacity, the fluid density is increased by using barite. those parameters it cannot be used in all oil wells (is used in this well to show the effect of mud density on transport ratio) because of the hydrostatic pressure consideration. also, the formation pressure for each drilled layer has effect on the value of the density, so it cannot be increase the value of density as we want. several investigators have proposed empirical correlations for estimating the cutting slip velocity like moore and chien correlation. the cutting transport efficiency in vertical wells is usually analyzed by computing the slip velocity, which is dependent on several factors such as: drilling fluid properties, operational parameters and particle property.here we have two drilled intervals in well a, which have been drilled in south of iraq, 12.25" hole section. at the first interval (446m to 1427m) the flow pattern was turbulent. table (14) contains field data about the first intervals. the criteria that we are depended on to find the type of flow laminar or turbulent is alternate method, this method is as below: 1calculate the slip velocity for laminar mode by using eq.8 … (8) 2calculate the slip velocity for turbulent mode by using eq.8 … (9) 3choose the lower value. for the first interval which was from 446 m to 1427 m, the flow pattern was turbulent by using eq. 8 and eq.9 the values of slips velocities are calculated. the turbulent mode shows the lowest slip velocity than laminar mode so the flow pattern in the first interval assumed to be turbulent flow. the second interval (1430 m to 2248m) the flow pattern was laminar. fig.7, the relation between t.r. and mud density for tow intervals in well a ,12.25" section enhancing the lifting capacity of drilling fluids in vertical oil wells 26 ijcpe vol.18 no.3 (sep. 2017) -available online at: www.iasj.net table 14, the relation between t.r. and mud density for the first oil well mud density ppg vs laminer ft./min vs turblent ft./min t.r. laminer t.r. turblent vm ft./min 145.5 9 67.76 60.56 0.53 0.58 cutting density ppg 20 9.3 65.80 58.76 0.55 0.60 dp ,inch 5 9.5 64.51 57.59 0.56 0.60 cutting size, inch 0.35 9.8 62.63 55.88 0.57 0.62 mf cp 8-10)) 10.1 60.78 54.23 0.58 0.63 rpm,rev./min 120 table 15, the relation between t.r. and mud density for the second oil interval mud density ppg vs laminer ft./min vs turblent ft./min t.r. laminer t.r. turblent vm ft./min 145.5 9 41.39 51.18 0.72 0.65 cutting density, ppg 20 9.3 40.19 49.66 0.72 0.66 dp ,inch 5 9.5 39.41 48.67 0.73 0.67 cutting size, inch 0.25 9.8 38.25 47.23 0.74 0.68 mf, cp 1416 10.1 37.12 45.83 0.74 0.68 rpm,rev./min 120 the increasing in the annular velocity at known penetration rate is result from tow reason: the first one: the decreasing in the cutting concentration in the annuals lead to decreasing in the bottom hole pressure, the second one: as a result the friction in the flow system, the bottom hole pressure increase rabia [17]. it can be get the annular velocity that will give the minimum bottom hole pressure, in other words, it can be reach to the best hole cleaning at the minimum bottom hole pressure ,therefore the annular velocity at minimum bottom hole pressure is known as optimum annular velocity. eq.10 is used to calculate the pressure gradient (bottom hole pressure (psi)/depth (ft)) for laminar flow. eq.11 is used to calculate the pressure gradient (bottom hole pressure (psi)/depth (ft)) for turbulent flow burgoyne [18]. fig 9. and table(16) clarify the relationship between annular velocity and bottom hole pressure. … (10) … (11) where: pwm: bottom hole pressure psi, d:hole depth ft , ρm:mud density ppg , ρ c: cutting density ppg , τ:shear stress , dh: hole diameter in , dp: pipe diameter in, ϻp: plastic viscosity cp, f:friction factor, k: velocity correction factor. when the mud velocity in the annular is greater than the optimum mud velocity, the bottom hole pressure increase as the annular velocity increase. when annular velocity is greater than critical velocity the flow amel habeeb assi -available online at: www.iasj.net ijcpe vol.18 no.3 (sep. 2017) 27 pattern is transform from laminar to turbulent and as shown fig 9. and table14. the optimum annular velocity is at minimum bottom hole pressure therefore; graphically from fig.9 it can be found it, it is about 94 ft/min. note: the data in in table 16 represent field data for well in south of iraq, mud density= 9.6-10-2)ppg , ρ c=22 ppg, dh =12.25" , dp= 8" .the data in table 16 is gotten by flowing gradient survey /slick line tools , is a device used to assess the well pressure and temperature while flowing from bottom to the up by quartz gages. fig .9, the relationship between annular velocity and bottom hole pressure. table 16, the relationship between annular velocity and bottom hole pressure annular velocity ft./min bottom hole pressure /depth psi/ft. flow type 75 0.965 laminar 75 0.952 laminar 75 0.946 laminar 76 0.935 laminar 79 0.897 laminar 81 0.88 laminar 88 0.856 laminar 94(vm)optimum 0.84 minimum bottom press. optimum annular velocity 100 0.841 turbulent 110 0.842 turbulent 130 0.843 turbulent 165 0.865 turbulent 179 0.887 turbulent 200 0.915 turbulent 230 0.938 turbulent 250 0.948 turbulent 270 0.96 turbulent enhancing the lifting capacity of drilling fluids in vertical oil wells 28 ijcpe vol.18 no.3 (sep. 2017) -available online at: www.iasj.net another way to increase av is to reduce the planned size of the annulus by using larger-od drill pipe. not only does a larger pipe generate a smaller annular gap, thereby increasing fluid velocity, it also increases the effect of pipe rotation on hole cleaning. although reducing the annular gap can greatly improve hole cleaning, it also makes fishing more difficult. table 17, field data odp ,in va ft./min other assumed data 6 257.75 dh ,in 6.5 272.70 12.25 7 290.91 q,gpm 7.5 313.39 1200 8 341.61 fig. 10 conclusions 1the results show that the slip velocity is decrease when the cutting size is decrease, that decreasing in the value of slip velocity lead to enhance the value of transport ratio. 2the results show that the annular velocity increases as the odp increases, that increase in the value of annular velocity lead to good hole cleaning. 3the experimental work show that the x-anthan polymer gave good values of cci comparing with the mixture of (bentonite and cmc) and oil base mud. 4from field application is found that the mud type and the flow rate have great effect on the value of cutting concentration in the annulus and lifting capacity. 5in a vertical hole, laminar flow with low pv and elevated yp or low nvalue and high k-value (from the power law model) will produce a flat viscosity profile and efficiently carry cuttings out of the hole. 6the viscosity is related with hole cleaning, and it has major effect on the value of lifting capacity than density, in other words moderate value of viscosity with high value of rpm give good hole cleaning. nomenclatures bha: bottom hole assembly. rop: rate of penetration, ft. /sec. rpm: revolution per minute, rev. /min. cci: carrying capacity index cmc: carboxymethyl cellulose pwm : bottom hole pressure.psi t.r. : transport ratio. av: annular velocity,fpm. aape: average absolute percentage error references 1darley, h. c. h., and gray, g. r. , 1986" composition and properties of oil well drilling fluids", 5th ed., gulf pub. co., houston. 2api 13a, may 1993 ,„„specification for drilling fluid materials,‟‟ american petroleum institute, washington d.c., 15th ed. 3walker, r. e., feb. 1971, „„drilling fluid rheology,‟‟ pp. 43–58. 4young, g., and robinson, l. h., sept.–nov. 1982 „„how to design a amel habeeb assi -available online at: www.iasj.net ijcpe vol.18 no.3 (sep. 2017) 29 mud system for optimum solids removal,‟‟ world oil. 5o‟brien, t. b., and dobson, m., „„hole cleaning: some field results,‟‟ spe iadc 13442, 1985 spe drilling conference, new orleans. 6api rp 13i, „„recommended practice, standard procedure for laboratory testing drilling fluids,‟‟ may 2000, american petroleum institute, washington, d.c.,6th ed. 7barnes, h. a., hutton, j. f., and walters, k., 1989. rheology series 3: an introduction to rheology, elsevier science b.v., new york, 8hopkin,e.a, 1697."factors affecting cutting removal during rotary drilling",aime of spe. 9robinson, l., 1981. "solid–liquid separation", chemical engineering series, butterworth & co. ltd., london. 10amoco production co., march 1994, solids control handbook. 11m-i llc, 2002, drilling fluids engineering manual, houston, tx,. 12api rp 13d, 2003, „„recommended practice on the rheology and hydraulics of oilwell drilling fluids,‟‟ american petroleum institute, washington, d.c., 4th ed. 13api rp 13b2, 2002, „„recommended practice for field testing oil-based drilling fluids,‟‟ american petroleum institute, washington, d.c., 3rd ed. dr qasim _mag_.doc ijcpe vol.8 no.4 (december 2007) 63 iraqi journal of chemical and petroleum engineering vol.8 no.4 (december 2007) 63-71 issn: 1997 -4884 the effect of time and corrosion products formation on corrosion rate of carbon steel pipe under turbulent flow conditions qasim j. slaiman*, basim o. hasan*, and shiemaa m. mahmood** * chemical engineering department college of engineering university of al-nahrain iraq ** chemistry department college of science university of al-nahrain iraq abstract the effect of time (or corrosion products formation) on corrosion rates of carbon steel pipe in aerated 0.1n nacl solution under turbulent flow conditions is investigated. tests are conducted using electrochemical polarization technique by determining the limiting current density of oxygen reduction in reynolds number range of 15000 to 110000 and temperature range of 30 to 60oc. the effect of corrosion products formation on the friction factor is studied and discussed. corrosion process is analyzed as a mass transfer operation and the mass transfer theory is employed to express the corrosion rate. the results are compared with many proposed models particularly those based on the concept of analogy among momentum, heat, and mass transport. the capability of these models to predict corrosion rates i n presence of corrosion products is examined and discussed. it is found that formation of corrosion products with time decreases the corrosion rate (or mass transfer rate) at low reynolds number and temperature while it increases the corrosion rate at high re and temperature. it increases momentum transport and this increase depends on temperature, reynolds number, and corrosion rate. increasing roughness due to the formation of corrosion products causes overestimation of analogy correlations results by increasing friction factor and decreasing corrosion rate. keywords: corrosion, carbon steel, time, corrosion product, friction factor, analogy. introduction the corrosion of carbon steel in neutral environments is of practical importance, therefore it is considered by many studies. it is widely recognized that the corrosion of carbon steel may be accounted for by the following anodic reaction: 2efefe 2 +→ + (1) and cathodic reaction in presence of oxygen, −→++ 2oh2eoho 222 1 (2) in many corrosion problems, there is strong evidence that the rate of uniform corrosion is controlled by the rate of mass transfer. this is true whether the corrosion fluid remains static or in fast motion with respect to the metal surface. however, molecular diffusion is not the only factor which influences the rate of corrosion. in addition, in turbulent fluids, the rate of transport of eddy diffusion appears to participate in the control of the over-all transfer rate [1]. it is accepted that the corrosion of mild steel in areated water is controlled by the rate of cathodic reduction of oxygen and hence by the oxygen transport from the main stream solution to the reacting surface. many studies [1,2,3,4,5] were carried out to express the corrosion pro cess, that is under diffusion control, as a mass transfer operation in terms of mass transfer parameters using modified form of reynolds analogy. these studies were performed for various metalenvironment systems. mass transfer theory can be applied to pre dict corrosion rates for diffusion controlled systems not exhibiting passivity phenomena. in previous study [6] the effect of re and temperature on the corrosion rate of carbon steel in aerated 0.1n nacl university of baghdad college of engineering iraqi journal of chemical and petroleum engineering the effect of time and corrosion products formation on corrosion rate of carbon steel pipe under turbulent conditions ijcpe vol.8 no.4 (december 2007) 64 solution for clean surface, where no corrosion products (t=0), was studied and the capability of analogy models to estimate the corrosion rate was examined. also the mass transfer theory was employed to express the effect of re and temperature on the corrosion rate. in present work it is aimed to investig ate the effect of time or corrosion products formation on the corrosion rate and on the applicability of the correlations that are based on the concept of analogy among mass, heat, and momentum transfer to examine to what extent it is possible to employ these correlations to predict corrosion rate by determining experimental friction factor at various intervals over the investigated range of re and temperature. in general, as the pipe corrosion proceeds, the process becomes more complex due to building up of corrosion products which restrain the oxygen transport to the surface, growth of the surface roughness which increases the momentum and mass transport between surface and solution, changing physico-chemical properties of the corrosion products; and chan ging mechanics of flow [3]. the most important study concerned the effect of time (or corrosion products formation) on the corrosion amount (weight loss) was that of mahato et. al. [3,7,8]. they used weight loss method to determine the effect of time on the corrosion amount. it was an excellent practical study since it considered long time of exposure but the shortcoming of this study was the relatively low re range. in addition to that, the weight loss method for determining corrosion rate gives the avera ge corrosion rate over the test period and not the instantaneous. accordingly, it is impossible by weight loss to understand the behavior of the corrosion rate during the formation of corrosion products layer. therefore, in the present work the limiting current density technique (lcdt) was employed to study the behavior of the corrosion rate during the growth of the corrosion products layer. mahato et. al. studies [3,7,8] revealed that corrosion products formation generally decreases the corrosion rate. this is not always true as will be discovered in present work. experimental work the dynamic system for performing the experimental work is illustrated in fig.1 pressure drop measurements the pressure drop across the test section was obtained employing an inverted u-tube manometer with static pressure taps located at the edges of the test section in the wall of the extension pvc pipe. the friction factor was obtained from pressure drop measurements for a pipe 20cm long for the entire range of re, temperature , and time. the solution with a particular re and temperature was pumped to the test section and the pressure drop qasim j. slaiman et al ijcpe vol.8 no.4 (december 2007) 65 across the latter was taken after 10 minutes from the test run start. this value of pressure drop was considered to be at time zero. as corrosion proceeds, there was a continuous growth of corrosion products layer with time and hence continuous increase in pressure drop and friction factor. therefore the values of pressure drop were recorded at different time intervals during the test period to obtain friction factor variation with time. each measurement was performed twice and the average was taken. polarization measurements the solution is prepared and circulated through by-pass to reach the required temperature by using heater and controller. the test section components (working electrode, counter electrode, reference electrode) were mounted in their positions. care was taken to insure that there were no discontinuities in the cross section of the pipe immediately up stream and down stream of the electrode. silicon rubber was used to prevent leakages in the test section. after the solution had reached the desired temperature, it was allowed to pass through the corrosion cell and the flow was adjusted to the desired re with the aid of two control valves. when the solution reached the test section, the electrical circuit was switched on. the specimen (working electrode) was cathodically polarized from a potential of nearly -1.4 v (vs. sce) to the corrosion potential (where iapp=0) at a rate of 5-20 mv by changing the applied current using rheostat. the current was recorded for step changes in potential. two minutes were allowed for steady state to be reached after each potential increment [9,10]. thus polarization curve can be drawn and the limiting current density can be obtained. the obtained values of il represent values for clean surface (t=0), i.e., no corrosion products were formed, since during the polarization experiment no free corrosion occured (except at low currents near the corrosion potential) because the specimen was cathodically protected. to investigate the influence of time on the instantaneous corrosion rate (or mass transfer coefficient), the electrical circuit was switched off and the specimen was allowed to corrode freely under flow of the corrosion solution at a particular re and temperature. a free corrosion of the specimen continues for 2.5 h during this interval corrosion products form on the surface of the pipe. at the end of 2.5 h the electrical circuit again switched on and the specimen was polarized to -1.4 v (vs. sce) and polarization was repeated to obtain the complete polarization curve and new il is determined. this value of il represents the value at t=2.5 h. at the end of the second polarization measurement the electrical circuit was switched off while the corrosion solution was kept flowing through the specimen for another 2.5 h. during this second interval the specimen will undergo a free corrosion forming additional corrosion products. the specimen was then p olarized to 1.4 v (vs. sce) by switching on the electrical circuit again to repeat the polarization experiment and to obtain new il at t=5 h. hence three values of il were obtained for each test run. each test run was repeated twice and the average was taken. results and discussion friction factor over the years, friction factor ( f ) has received a wide attention from many authors. numerous studies have been performed to study the factors influencing friction factor under different conditions, e.g., isothermal and heat transfer conditions [6,10,11,12,13,14,16,22] and roughness conditions [11,14,17,18,19,20,21]. most of these studies have showed that the main two variables influencing f were re and surface roughness. in previous work [6] the effect of re on f was studied and discussed. in present work the effect of time or roughness produced from corrosion products on the friction factor over the whole range of re and temperature is considered. determining f at different time intervals during the corrosion process serves to understand the effect of corrosion products formation on friction factor and calculating the instantaneous corrosion rate (or mass transfer coefficient) from the proposed analogy models that are based on friction factor in order to compare with actual instantaneous corrosion rates obtained from il. figures.2 show the variation of friction factor with time for the whole range of re and temperature. it is clear that f increases with time due to increased roughness of the corroding wall. this increase depends on re, temperature, and corrosion rate. figure 3 shows a plot of the relative increase in friction factor (f/fo) with time with re as a parameter. observing these figures indicate that at a particular temperature the higher the re is the higher the increase in f (or f/fo) due to higher corrosion rate. it is evident also that for re=80000 the maximum value of f/fo at 30oc is 1.3, at 45oc is 1.5, and at 60oc is 1.42, i.e., in spite of the corrosion rate at 60oc is higher than at 45oc , the relative increase in f is lower. this can be attributed to three reasons: (i) increasing temperature leads to decrease the viscosity which plays an important role in decreasing pressure drop [15,23] causing lower f values at a particular time. (ii) increasing temperature affects the nature of corrosion products layer particularly density and porosity [7], i.e, the rough nature of this layer decreases with temperature rise leading to lower pressure drop and hence lower f (or f/fo). (iii) solubility and erosion of corrosion products layer at high temperatures and re leading to reduce the growth of this layer and hence the increase of f. fig.4 shows the variation of friction factor with re for rough (corroded) surface. the the effect of time and corrosion products formation on corrosion rate of carbon steel pipe under turbulent conditions ijcpe vol.8 no.4 (december 2007) 66 formation of corrosion products with time deviates the relation between f and re from smooth surface behavior, i.e, the friction factor increases with re rather than decreases. the higher the smoothness of surface is the higher the decrease of f with re. studies for fully rough surface [20, 21, 24, 25] showed that no effect for re on f at high values of re and the higher the surface roughness the lower the decrease of f with re. this independency of the friction factor on re in fully rough region is interpreted as follows: as re (or velocity) increases the thickness of the momentum boundary layer decreases and eventually the protrusions penetrate the boundary layer and the behavior deviates from that of smooth pipe [25]. add to that, as re increases, the corrosion rate increases resulting in more corrosion products and hence the friction factor increases. 0 100 200 300 400 tim e (min) 6.5 7.0 7.5 8.0 8.5 9.0 9.5 f 1 0 3 x t =30 c re=80000 re=65000 re=45000 re=20000 o fig. 2a:variation of friction factor with time for various re at 30oc 0 100 200 300 400 time (min) 6 7 8 9 10 11 12 f 1 0 t=45 c re=88000 re=80000 re=60000 re=45000 re=35000 3 x o fig. 2b:variation of friction factor with time forvarious re at 45oc 0 100 200 300 400 time (min) 6 7 8 9 10 11 f 1 0 3 x t=60 c re=113000 re=80000 re=60000 re=45000 re=35000 o fig.2c:variation of friction factor with time for various re at 60oc 0 100 200 300 400 time (min) 0.8 1.0 1.2 1.4 1.6 1.8 f/ f t=45 c re=8 8000 re=8 0000 re=6 0000 re=4 5000 re=2 0000 o o fig.3:variation of relative friction factor ( f/fo ) with time at 45oc it is not possible to correlate corrosion amount with friction factor increase for two reasons. firstly, at low re no pronounced increase in friction factor with time (figs.2) for all temperatures despite of corrosion (as indicated by polarization measurements). secondly, erosion at high re and temperature restricts the growth of product layer and consequently the increase in f. corrosion rate studyin g the limiting current density behavior with time serves to understand the influence of re, temperature, and corrosion products formation on the instantaneous corrosion rate. the effect of time is due to qasim j. slaiman et al ijcpe vol.8 no.4 (december 2007) 67 2 3 4 5 6 7 8 9 100000 re 2 3 4 5 6 7 8 9 2 3 4 5 6 7 8 10 f 1 0 3 t=6 hr t=60 c t=45 c t=30 c o x fig.4:variation of friction factor with re for rough surface (t=5 h). the continuous growth of the corrosion products layer which affects the transport of o2 to metal surface and the activity of the surface and hence the corrosion rate (or mass transport rate) [1,7]. figures.5 show the polarization curves for re=20000 at different intervals for three temperatures. figures.6 show the variation of il with time at the three temperatures with re as a parameter. the figures indicate that the formation of corrosion products with time may increase or decreas e il, depending on the values of re and temperature. at 30oc, fig.6a shows that for all re, il decreases with time. at 45oc, fig.6b shows that for low re, il slightly decreases with time. as re increases, the decrease in il with time gradually vanishes. at high re, a slight increase of il with time can be observed. also it can be noted that at moderate re, the il decreases with time and then increases. at 60oc, fig.6c indicates that for low re, there is a slight decrease in il with time. at moderate re, il remains nearly unchanged, and at high re, il appreciably increases with time. in fact, this is surprising finding where the previous studies [3,7,8] indicated that the corrosion rate always decreases with time. to interpret this phenomena; mahato et. al. [3] stated that the corrosion process consists of four steps: (i) diffusion of o2 to the solid -liquid interface through a viscous sub layer; (ii) diffusion of dissolved o2 through the corrosion products layer (iii) reaction at the surface; (iv) precipitation of corrosion products at the solid surface. as corrosion proceeds the amount of corrosion products increases for the whole investigated range of temperature and re which can be concluded from pressure drop (or friction factor) measurements (figs.2). at 30oc, the growth of corrosion products layer will reduce the amount of o2 arriving to the surface and therefore il will be decreased. at 45oc and 60oc, since the corrosion rate is higher than at 30oc, the thickness of corrosion products layer will be greater for same re. during the initial period the corrosion products are developing within the viscous sub -layer. as the thickness of corrosion products increases with time, the protrusions height increases until it becomes greater than the thickness of viscous sub -layer (db) and hence at high re the turbulence at the peaks of these protrusions increases leading to decrease the thickness of diffusion sub-layer (dd) which is a fraction of viscous sub-layer and represents the main resistance to mass transfer [3,20,22,26,27,28,29]. therefore as re increases, the turbulence around and inside the corrosion products layer increases leading to decrease db and dd and more o2 arriving to the surface and hence higher corrosion rate. the eddy mass transfer resulting from extreme surface roughness will have an important role in the mass transfer of reactant from the main liquid bulk to the solid surface [7]. evans [30] indicated the greater turbulence due to high velocities results in more uniform o2 concentratio n. this shows how the corrosion products increase the corrosion rate rather than decrease it (for the investigated range of time). also the rise in temperature may contribute to increase the porosity (or decrease the density) of corrosion products layer and that facilitates the passage of o2 toward the surface [7]. this is why the effect of corrosion products in reducing the corrosion rate decreases with increasing temperature at a particular re. dawnson and trass [17] and berger and hau [31] found that the surface roughness enhances the mass transfer rate. kandlikar et. al. [14] and oziski [32] ascribed the enhancement of heat transfer rate in rough surfaces to the disturbance of viscous sub-layer by the protrusions. it is to be remembered that the roughness produced from the accumulation of corrosion products is different from the roughness that is an inherent property of the metal wall. 1 10 100 1000 cur rent densit y ( a/cm ) -1. 60 -1. 40 -1. 20 -1. 00 -0. 80 -0. 60 -0. 40 e , v ( s c e ) t=30 c, re =20000 t=0 t=2.5 h r t=5 hr o µ 2 the effect of time and corrosion products formation on corrosion rate of carbon steel pipe under turbulent conditions ijcpe vol.8 no.4 (december 2007) 68 10 100 1000 curre nt density( a/cm ) -1.4 -1.2 -1.0 -0.8 -0.6 e , v (s c e ) t=45 c, re=2000 0 t=0 t=2.5 hr t=5 hr µ o 2 0 1 1 0 100 1000 currenty dens ity ( a/cm ) -1 .4 -1 .2 -1 .0 -0 .8 -0 .6 e , v (s c e ) t=60 c, re=2 0000. t=0 t=2.5 hr t=5 hr µ 2 o figs.5: cathodic polarization curves showing the effect of time 0 2 3 5 6 time (hr) 150 300 450 600 750 900 i ( a /c m ) t=30 c re=65 00 0 re=60 00 0 re=45 00 0 re=35 00 0 re=20 00 0 re=15 00 0 l µ 2 o 0 2 3 5 6 time ( hr) 150 300 450 600 750 900 1050 1200 1350 1500 i ( a /c m ) t=45 c re=88 00 0 re=73 00 0 re=60 00 0 re=35 00 0 re=20 00 0 l µ 2 0 2 3 5 6 time(hr) 2 4 6 8 10 12 14 16 18 i ( a /m ) t=60 c re=113000 re=101000 re=80000 re=60000 re=45000 re=35000 re=20000 µ 2 l o fig. 6: variation of il w ith time for different re,(a) 30oc (b) 45oc, (c) 60oc mass transfer the formation of corrosion products with time influences the mass transfer rate of oxygen from the bulk to the metal surface. the limiting current density technique permits the estimatio n of the instantaneous value of experimental k and consequent dimensionless groups (sh) via determining il. the determination of k+ requires the determination of friction factor. figs.7 shows the variation of sh with re at various temperatures with time as a parameter. these figures indicate that at 30oc and 60oc time effect on sh is more than at 45oc. at 30oc, the formation of corrosion products causes a significant decrease in sh for all re range. at 60oc, the time effect varies with re, i.e., at low re, the sh decreases with time via deposition of corrosion products. as re increases at this temperature qasim j. slaiman et al ijcpe vol.8 no.4 (december 2007) 69 the effect of time on sh decreases. at high re, sh significantly increases with time, i.e., the corrosion rate (or k) at time 5 h is higher than at time zero (clean surface). at 45oc, slight decrease in mass transfer rate (or sh) with time occurs at low re and less or negligible at high re values. also it is found that the formation of corrosion products increases the dependence of sh on re for all temp eratures. the following correlations are obtained by best fit method for rough surface at t=5 h: sh=0.279 re0.676 c.c=0.88 t=30°c 15000 < re < 80000 (3a) sh=0.085 re0.807 c.c=0.99 t=45 °c 15000 < re < 88000 (3b) sh=0.073 re0.828 c.c=0.98 t=60°c 20000 < re < 113000 (3c) comparing eqs.(3) for rough surface (t>0) with that obtained for clean surface (t=0) in previous study [6], i.e, sh=5.588 re0.434 c.c=0.97 t=30 °c 15000 < re < 80000 (4a) sh=0.375 re0.677 c.c=0.99 t=45 °c 15000 < re < 88000 (4b) sh=2.799 re0.514 c.c=0.97 t=60°c 20000 < re < 113000 (4c) indicates that the presence of corrosion products appreciably increases the dependence of sh (or corrosion rate) on re. at 30oc the increased roughness increases the effect of re on sh but decreases the value of sh at a particular re. the maximum increase occurs at 60oc where the increased roughness considerably increases the effect of re on sh. this increase in the effect of re on sh is attributed to the increased turbulence as has been found by other studies concerning momentum, heat, and mass transfer on rough surfaces [8,14,22,25]. it should be noted that this type of roughness (i.e corrosion products) generally decreases the mass transfer rate (except at high re and temperature) but it increases the effect of re on mass transfer rate for all temperatures. this is a difference point between this type of roughness and the roughness of a normal metal, where most of heat and mass transfer studies [14,17,18,19,20,21,24,31] showed that the latter increases the heat or mass transfer rates always. 2 3 4 5 6 7 8 9 100000 r e 2 3 4 5 6 7 8 9 100 1000 s h sc=334 .4 , t=30 c t=0 t=2.5 hr t=5 hr o 2 3 4 5 6 7 8 9 100000 re 2 3 4 5 6 7 8 9 2 100 1000 sh s c=184.8, t=45 c t=0 t=2.5 hr t=5 hr o 2 3 4 5 6 7 8 9 100000 re 2 3 4 5 6 7 8 9 2 1000 s h sc =99.1, t=60 c t=0 t=2.5 h r t=5 hr o figs.7: variation of sh with re at various intervals comparison with proposed models corrosion products formation affects the capability of correlations based on the analogy concept to estimate the corrosion rate, i.e., the presence of corrosion products increases the difference between the experimental corrosion rate and that obtained from analogy models (many analogy models have been presented in previous paper [6]) due to two causes, first is the change in experimental sh, and second is the increase in analogy sh via increasing friction factor.figs.8 show a comparison between experimental sh and that obtained from analogies for t=5 h, i.e., in the presence of corrosion products at all temperatures. at 30oc, it is evident from fig.8a that the time causes some difference between sh predicted by von karmn [33] analogy (eq. 5) and experimental sh. this difference increases as re increases. this is due to two reasons, (i) the decrease of experimental the effect of time and corrosion products formation on corrosion rate of carbon steel pipe under turbulent conditions ijcpe vol.8 no.4 (december 2007) 70 corrosion rate by the formed corrosion products, (ii) the increase in the corrosion rate estimated from analogy correlations due to increasing friction factor ( f ) via corrosion products. at this temperature the difference reaches 90% at high re. accordingly, at 30oc overestimation is expected from the analogy models. at 45oc and 60oc, fig.8b and fig.8c reveal that the presence of corrosion products increases the difference between experimental sh and analogy sh especially at high re due to high friction factor increase (f/fo). the difference reaches 40% at high re. at 60oc, the presence of corrosion products increases the experimental sh at high re, thus the difference is mainly due to the increased f. generally at low re the difference between analogy predictions and actual corrosion rates is mainly due to the decrease in experimental values induced by the formation of corrosion products, because the increase in f is slight, while at high re the difference is mainly due to the increase in friction factor, since the effect of corrosion products on actual corrosion rate at high re is almost low as has been demonstrated.     −++−+ = ))1( 6 5 1ln(12/51 re)2/( scscf scf sh (5) to reduce the deviation of the corrosion rates estimated using analogy correlations from actual corrosion rates, the analogy correlations should be based on the initial friction factor, fo (t=0). in other word, the change in friction factor is neglected and the analogy correlation is always based on the initial frict ion factor. by this way it is possible to reduce the increase in analogy results by the following percentage: error reduction= 100)1n)((100 n nn o ×−=× − = o f f reductionerror of ff (6) where n is the dependence of a particular analogy correlation on f . if n=1, when the increase in f is f/fo=1.5, the error reduction is 50%, and so on. 2 3 4 5 6 7 8 9 100000 re 2 3 4 5 6 7 8 9 2 100 1000 s h sc=334 .4 , t =3 0 c e xperimenta l (t =0 ) e xperimenta l (t =5 hr) von karman(t =0 ) [vo n ka rma n (t =5 hr) o 2 3 4 5 6 7 8 9 100000 re 2 3 4 5 6 7 8 9 1000 s h sc =184.8, t=45 c exp er imen tal(t= 0) exp er imen tal (t= 5 h r) von karm an (t=0) von karm an (t=5 hr) o 2 3 4 5 6 7 8 9 100000 re 2 3 4 5 6 7 8 9 2 1000 sh s c=99.1, t=60 c exp erim ental(t=0) exp erim ental(t=5 hr ) von kar mn(t=0) von kar man (t=5 hr) o figs.8: comparison of analogy models and experimental results in presence of corrosion products conclusions 1. corrosion products formation with time decreases the corrosion rates at low re and temp erature, while it increases the corrosion rates at high re and temperature. also the formation of corrosion products increases the corrosion rate (or mass transfer rate) dependence on re for all temperatures. 2. friction factor increases with time due to the formation of corrosion products for all re and temperatures. the higher the re is the higher the increase in friction factor with the increased corrosion amount. 3. overestimation is obtained from analogy correlations with the formation of corrosion products , by increasing friction factor and decreasing experimental k, particularly at low re and temperature. basing analogy correlations on the initial friction factor for clean surface reduces this overestimation. qasim j. slaiman et al ijcpe vol.8 no.4 (december 2007) 71 nomenclature f friction factor. fo friction fa ctor for clean surface i current density, a/m2. il limiting current density, a/m 2. k mass transfer coefficient, m/s. re reynolds number sh sherwood number= kd/d. st stanton number= k/u u* friction velocity, m/s. µ viscosity, kg/m.s2. ? kinematic viscosity , m2/s. db viscous sub-layer thickness, µm. dd diffusion layer thickness, µm. c.c. correlation coefficient references 1 j. marangozis, corrosion, vol.24, no. 8, p. 255, 1968. 2 b.t ellison and w. r. schmeal, j. elerctchem. soc., vol. 125, no. 4, p. 524,1978. 3 b. k. mahato, c. y. cha, and w. shemlit, corros. sci., vol. 20, p. 421, 1980. 4 n.r.k. vilambi and d.t. chin, electchem. soc., vol.134, no.1, p.2501, 1982 5 b. poulson and r. robinson, corr. sci., vol. 26, no.4, p. 265, 1986. series, leonard hill book co., 1966. 6 qasim.j. slaiman and b.o. hassan, baghdad, journal of engineering, no.4 , vol. 11, 2005. 7 b.k. mahato, f.r. stewrd, and l. w. shimlit, corrs. sci. vol.8, p.737, 1968 8 b. k. mahato, s. k. voora and l.w. shemilt, corros. sci., vol.8, p. 173, 1968 9 d. j. pickett and k. l. ong, electchmica acta, vol. 19, p.875, 1974. 10 m. a. atia, ph.d. thesis, dept. chem. eng., saddam university, baghdad, 1996. 11 j. g. knudsen and d. l. katz, fluid dynamics and heat transfer, mc graw hill, new york, 1958. 12 b. s. petukhov, heat transfer and friction in turbulent pipe flow with variable physical properties, advances in heat trans., vol. 6, p. 503, 1970. 13 a. p colburn, trans. aiche, vol. 29, p. 174, 1933. republished in: j. heat mass transfer, vol.7, p. 139, 1964. 14 s. g. kandilkar, s. joshi, s. tian, heat transfer for conference, 35th national, amse, california, 2001. 15 j.w. smith and n. epstein, effect of wall roughness on convective heat transfer in commercial pipes, a.i.ch.e. j., vol. 3, no. 2, 1957. 16 b. pinkel, cleveland, and ohio, amse, february, p.305, 1954. 17 a. dawnson and o. trass, int. j. heat mass trans., vol.15, p.1317, 1972. 18 v. kolar, , int. j. heat mass trans., vol. 8, p. 639, 1965. 19 r. e. acosta.r.h. muller, and c.w tobias, aiche, vol. 31, no.3 p.473, 1985. 20 n. l. vuichanov and v. d. zimparer, j. heat mass transfer, vol. 32, p. 29, 1988 21f.f. moody,trans. asme, vol. 66, p.671,1944. 22 r. s. brodkey and h. c. hershey, transport phenomena, 2nd printing, mc graw hill, new york, 1989. 23 j. m. coulson and j. f. richardson, chemical engineering, 5th edition, butter worth heinemann, britain, 1998. 24 d.f. dipprey and r.h. sabersky, heat and momentum transfer in smooth and rough tubes at various prandtl numbers, heat mass transfer, vol. 6, p.329, 1963. 25 .f.douglas and r.d. matthews, solving problems in fluid mechanics, vol.2, 3 rd ed., longaman, england, 1998. 26 j. r. welty, c. e. wicks, a nd g. rorrer, fundamentals of momentum, heat, and mass transfer, 4th edition, john wiley and sons, united states of america, 2001. 27 c. o. bennett and j. e. myers, momentum, heat and mass transfer, 3rd edition, mc graw hill, united states, 1982. 28 w. j. thomson, introduction to transport phenomena, 1st edition, prentice hall ptr, new jersey, 2000. 29 c. s. lin, r. w. moulton, and g.l. putnam et al, ind. eng. chem.,vol.45, p. 636, 1953. 30 u.r. evans, and t.p. haoar, proc. roy. soc, london, (series a), vol. 137, p.343, 1932. 31 f.b.berger and k.f. hau, int. j. heat mass trans., vol.22, p.1645, 1979. 32 m. n. ozisk, heat transfer, 3 rd edition, mcgraw hill, new york, 1988. 33 von karman, trans. asme, vol. 61, p. 5, 1939. iraqi journal of chemical and petroleum engineering vol.15 no.2 (june 2014) 1-7 issn: 1997-4884 ethanol-water separation by pressure swing adsorption (psa) zaid a. abdel-rahman*, abdulrahman m. mahmood* and ahmed j. ali** *chemical engineering department college of engineering tikrit university iraq **chemical engineering department faculty of engineering sohar university oman abstract single long spiral tube column pressure swing adsorption (psa) unit, 25 mm diameter, and 6 m length was constructed to study the separation of water from ethanol at azeotropic concentration of 95 wt%. the first three meters of the column length acted as a vaporizer and the remaining length acted as an adsorber filled by commercial 3a zeolite. the effect of pressure, temperature and feed flow rate on the product ethanol purity, process recovery and productivity were studied. the results showed that ethanol purity increased with temperature and pressure and decreased with feed flow rate. the purity decreased with increasing productivity. the purity range was 98.9 % to 99.6 %, the recovery range was 0.82 to 0.92 and the productivity range was 0.3 to 1.05 kg ethanol/kg zeolite.h. keywords: psa, azeotropic point, 3a zeolite, ethanol-water separation. introduction the main problem of using ethanol as a car fuel is the presence of excess water. simple binary distillation is used to separate ethanol-water up to maximum 95% as weight percent; further purity of ethanol cannot be got by distillation due to presence of azeotrope. there are many processes to get dehydrated ethanol beyond azeotropic point; pressure swing adsorption (psa) process in vapor phase is the lowest energy consumption process [1]. in liquid phase water adsorption for ethanol-water mixture [2-4], the adsorbent is usually desorbed by solvent rinse or heating. solvent rinse requires a suitable solvent and further separation and recovery of the solvent after the rinse. and the method of heating requires long operating period of heating for desorption and then cooling for adsorption, which lowers the productivity of the adsorbent beds. heat energy is also required to evaporate the liquid remaining in the void of the beds and raise the temperature of the adsorbent and the beds. the gaseous phase adsorption process was proposed by ladisch and coworkers [5]. psa is widely used in the separation and purification of gas mixtures mainly because of the easy and quick desorption of the adsorbent only by depressurization [6]. all adsorption processes include two major steps, adsorption and desorption, and almost the process is named by the desorption step. there are two basic adsorption processes: thermal swing adsorption (tsa) and pressure swing adsorption (psa). figure 1 shows the iraqi journal of chemical and petroleum engineering university of baghdad college of engineering ethanol-water separation by pressure swing adsorption (psa) 2 ijcpe vol.15 no.2 (june 2014) -available online at: www.iasj.net principles of the two processes in both adsorption and desorption [7]. fig. 1: principles of thermal swing adsorption (tsa) and pressure swing adsorption (psa) [7] desorption step takes rather long time (several minutes to hours) if the thermal swing is used due to slow heat transfer in packed columns while desorption steps takes short time (seconds to minutes) if the pressure swing is used. despite many researches on the adsorption of water on 3a zeolite and psa simulation for ethanol-water mixture [8-14], there are limited studies on the experimental psa process systems [15-18]. the aim of the present work is to construct a small scale pressure swing adsorption (psa) unit for the separation of the vapor mixture of ethanol-water beyond azeotropic point, using long spiral bed column, packed with commercial 3a zeolite. the effects of the operating parameters, such as adsorption pressure, adsorption temperature and feed flow rate on the performance of psa unit is to be studied, using 4-steps cyclic operations. the performance is characterized by ethanol product purity, ethanol recovery and ethanol productivity. experimental work figure 2 shows the experimental setup of the long novel spiral column psa process. the spiral column is of stainless steel 25 mm diameter and 6 m length. the first three meters act as a vaporizer and the last three meters act as an adsorber filled with one kilogram of 3a zeolite. the spiral coil submerged in oil bath. four solenoid valves of 6 mm diameter are used. the characteristic of the adsorbent is shown in table 1. the ethanol purity is measured by abbe refractometer, atago, japan. fig. 2: experimental setup table 1: adsorbent characteristics adsorbent type zeolite 3a shape sphere weight 1 kilogram particle diameter 3-5 mm structure formula 0.45k2o.0.55na2o.al2o3.4.5h2o bulk density 779kg/m 3 bed porosity 0.41 the parameters considered in the present work are:  operating adsorption temperature (tads): 150, 160 and 170 °c.  operating adsorption pressure (pads): 2, 3 and 4 bar.  feed flow rate (q): 1, 2 and 3 l/h zaid a. abdel-rahman, abdulrahman m. mahmood and ahmed j. ali -available online at: www.iasj.net ijcpe vol.15 no.2 (june 2014) 3  cycle time: 12 minutes (6 minutes adsorption and 6 minutes desorption).  feed concentration : 95 wt %  vacuum desorption pressure (pdes): 0.2 bar the experiments were organized by a three level factorial design of the three operating variables (temperature, pressure, and feed flow rate). the experimental procedure was: 1. turn on the oil path and start the control board on manual mode to prepare the system by vacuum and n2 purging. 2. set the control board on automatic mode with the specified duration of each step and with the solenoid valves operation cycle as shown in table 2 and fig. 3 for 4-steps psa operation. 3. adjust the flow rates of feed by regulating the dose pump. 4. take a sample of product each step and measure the product purity (etoh %) by calibrated refractometer. table 2: automatic solenoid valves operation of the 4-step psa system process steps solenoid valves sv1 sv2 sv3 sv4 adsorption pressurizing open close close close producing open close open close desorption depressurizing close open close open vacuum desorption close open close open fig. 3: sequence of the 4-steps pressure swing adsorption operation results and discussion figure 4 shows the effect of temperature and pressure on product ethanol purity at different levels of feed flow rate. no significance effect of temperature and pressure is noticed on the purity at low feed flow rate of 1 l/h. whereas significance effects of both temperature and pressure are noticed at high feed flow rate of 2 and 3 l/h. ethanol purity increases with increasing temperature because the increase of temperature leads to more heat for endothermic desorption process to be more complete at high temperature [10]. ethanol purity decreases with the pressure increase, in contrast of what expected. the capacity of the adsorbent increases and the vapor velocity inside the column decreases with increasing the adsorption pressure. these lead to increasing the performance of the psa process [10]. the reason of this unexpected result is due to that adsorbent exhibits more adsorbation in unit time in pressurizing step. figure 5 shows the effect of feed flow rate on product ethanol purity for different levels of pressure and temperature of 150 o c. the purity decreases with increasing the feed flow rate because solid adsorbent exhibits more adsorbation for unit time which makes the column approaches sooner the breakthrough point and saturation early. the same trends were noticed at temperatures of 160 and 170 o c. ethanol-water separation by pressure swing adsorption (psa) 4 ijcpe vol.15 no.2 (june 2014) -available online at: www.iasj.net fig. 4: temperature and pressure effect on ethanol purity (a: q=1 l/h, b: q=2 l/h, c: q=3 l/h) fig. 5: effect of feed flow rate on ethanol purity (t=150 °c) figure 6 shows the effect of temperature and pressure on ethanol recovery at feed flow rate of 1 l/h. ethanol recovery decreases with increasing temperature and pressure because ethanol losses during desorption step increases with increasing temperature and pressure. the same trends were noticed at feed flow rate of 2 and 3 l/h. fig. 6: temperature and pressure effect on recovery (q=1 l/hr) figure 7 shows the effect of temperature and pressure on the system productivity at different levels of feed flow rate. the productivity decreases with increasing temperature and pressure because ethanol losses during desorption step increases with temperature and pressure increase. fig. 7: temperature and pressure effect on productivity (kg ethanol/kg zeolite.hr) [a: q=1 l/h, b: q=2 l/h, c: q=3 l/h] zaid a. abdel-rahman, abdulrahman m. mahmood and ahmed j. ali -available online at: www.iasj.net ijcpe vol.15 no.2 (june 2014) 5 figure 8 shows that ethanol recovery slightly increases with increasing the feed flow rate. this is because ethanol losses in the desorption or depressurizing step are not affected by the change of the feed flow rate. fig. 8: effect of feed flow rate and pressure on ethanol recovery (t=150 °c) figure 9 shows that the system productivity is directly proportional to the feed flow rate. the relationship of product purity and the productivity is shown in fig. 10. the product purity decreases with increasing the productivity. this result is in agreement with the published literature [15]. fig. 9: effect of feed flowrate and pressure on productivity (t=150 °c) fig. 10: purityproductivity relationship conclusion 1. pressure swing adsorption (psa) experiments using zeolite 3a shows high performance in ethanol-water separation and produce high purity ethanol of about 99.5 wt%; that can be used as a car fuel. 2. no significance effect of temperature and pressure on ethanol purity at low feed flow rate of 1 l/h, while there was significant effect at high feed flow rate of 2 and 3 l/h. the purity increases with temperature increase. whereas the purity decreases with pressure increase. 3. ethanol purity decreases with increasing the feed flow rate. 4. recovery is slightly changed, with a range of 0.82 to 0.92 for all operating conditions. 5. productivity is directly proportional to the feed flow rate. it is of a wide range of 0.3 to 1.05 kg ethanol/kg zeolite. h. 6. ethanol purity decreases with increasing productivity. nomenclature p operating pressure, bar pads operating adsorption pressure, bar pdes operating desorption pressure, bar q feed flowrate, l/h q adsorbent capacity at operating conditions, kg water/kg adsorbent qads adsorbent capacity at adsorption conditions, kg water/kg adsorbent qdes adsorbent capacity at desorption conditions, kg water/kg adsorbent t operating temperature, o c tads operating adsorption tdes operating desorption temperature, o c ethanol-water separation by pressure swing adsorption (psa) 6 ijcpe vol.15 no.2 (june 2014) -available online at: www.iasj.net references 1jeong, j. s., jeon, h., ko, k.m., chung, b., and choi, g.w., production of anhydrous ethanol using various psa (pressure swing adsorption) processes in pilot plant, renewable energy 42, 41-45 (2012). 2teo, w.k. and d.m. ruthven, “adsorption of water from aqueous ethanol using 3a molecular sieves,”ind. eng. chem. proc. des. dev., 25(1), 17–21 (1986). 3carton, a. et al., “separation of ethanol-water mixtures using 3a molecular sieve,”j. chem. tech. biotechnol., 39, 125–132 (1987). 4sowerby, b. and b.d. crittenden, “scale-up of vapour phase adsorption columms for breaking ethanol-water azeotrope,”i. chem.e. symp. ser., 118(1991). 5ladisch, m., r., and tsao, g., t., “vapor phase dehydration of aqueous alcohol mixtures” us 4345973 (1982). 6guan, j., hu x., “simulation and analysis of pressure swing adsorption process by the electrical analogue” separation and purification technology 31, 31-35 (2003). 7ruthven, d.m., farooq, s., and knaebel, k.s., pressure swing adsorption vch publishers inc: new york, (1994). 8leo, d., m., “adsorption of water and ethanol vapors on 3a and 4a molecular sieve zeolites” msc. thesis, state university of new york at buffalo, may 1 (2007). 9sivashanmugam s., “comparison of commercial 3a zeolites for the ethanol-water separation using pressure swing adsorption”, msc. thesis, state university of new york at buffalo, december 5 th (2008). 10simo, m., “pressure swing adsorption process for ethanol dehydration” phd thesis state university of new york at buffalo, december 4 th (2008). 11simo, m., sivashanmugam, s., brown, c., j., and hlavacek v. “adsorption/desorption of water and ethanol on 3a zeolite in nearadiabatic fixed bed” ind. eng. chem. res., 48, 9247–9260 (2009). 12simo, m., brown, c. j., hlavacek, v., “simulation of pressure swing adsorption in fuel ethanol production process” computers and chemical engineering 32, 1635–1649 (2008). 13chen, y-h, wu, c-p, yang h-s and chou, c-t “simulation and design of numerical experiment of pressure swing adsorption process in separation of ethanol-water mixture” the 13th asia pacific confederation of chemical engineering congress apcche 2010, taipei, r.o.c. october 5-8 (2010). 14sowerby, b., and crittenden, b.,d., “an experimental comparison of type a molecular sieves for drying the ethanol-water azeotrope” gas separation and purification, vol 2 june 7783(1988). 15carmo, m. j., gubulin, j.c. “ethanol-water separation in the psa process”. adsorption 8: 235– 248, (2002). zaid a. abdel-rahman, abdulrahman m. mahmood and ahmed j. ali -available online at: www.iasj.net ijcpe vol.15 no.2 (june 2014) 7 16kupiec, k., rakoczy j., zieliński l., and georgiou, a., “adsorption– desorption cycles for the separation of vapour-phase ethanol/water mixtures”, adsorption science and technology, 26 (3), (2008). 17pruksathorn, p., and vitidsant, t. “production of pure ethanol from azeotropic solution by pressure swing adsorption” american j. of engineering and applied sciences 2 (1): 1-7 (2009). 18jeong, j-s, jang, b-u, kim y-r, chung, b-w, and choi g-w “production of dehydrated fuel ethanol by pressure swing adsorption process in the pilot plant” korean j. chem. eng., 26(5), 1308-1312 (2009). iraqi journal of chemical and petroleum engineering vol.18 no.2 (june 2017) 125 138 issn: 1997-4884 comparative study for removal of zn +2 ions from aqueous solutions by adsorption and forward osmosis tamara kawther hussein environmental engineering department, college of engineering, university of al mustansiryiah iraq abstract the aim of this paper was to investigate the removal efficiencies of zn +2 ions from wastewater by adsorption (using tobacco leaves) and forward osmosis (using cellulose triacetate (cta) membrane). various experimental parameters were investigated in adsorption experiment such as: effect of ph (3 7), contact time (0 220) min, solute concentration (10 100) mg/l, and adsorbent dose (0.2 5)g. whereas for forward osmosis the operating parameters studied were: draw solution concentration (10 150) g/l, ph of feed solution (4 7), feed solution concentration (10 100) mg/l. the result showed that the removal efficiency by using adsorption was 70% and the removal efficiency by using forward osmosis was 96.2 %. key words: tobacco leaves; adsorption; forward osmosis; heavy metal wastewater; membranes separation. introduction heavy metals are considered an important sources of environmental pollution. generally heavy metals are those whose density exceeds 5 g/cm 3 [1]. removal of heavy metals from wastewater is very important because it is toxic to human bodies and tend to bioaccumulate which may lead to anemia, and damage to lung, brain, and kidney [2]. zinc is one of the toxic metals that causes depression, lethargy, nausia, vomiting, and neurological signs. the important sources of zinc metal pollution are the combustion of petroleum and its products, and incineration of solid waste [3]. to reduce the heavy metals content of industrial effluents waste water, many different techniques have been utilized such as chemical precipitation, electrolytic methods, filtration, and ion-exchange, membrane processes. all these methods have their advantages and limitations in application such as incomplete heavy metals removal, require high energy, toxic sludge production and expensive equipment. so more effective methods have been utilized to remove metal pollution like adsorption and membrane process [4]. to show effective adsorption of heavy metals, many studies using agricultural products and by-products such as walnut shells, peanut skins, wool, tea leaves, coffee powder, sugar beet pulp, hazelnut shell [5], granular activated carbons [6], rice husk [7], university of baghdad college of engineering iraqi journal of chemical and petroleum engineering comparative study for removal of zn+2 ions from aqueous solutions by adsorption and forward osmosis 126 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net and maize husk [8]. the advantages of adsorption are relatively low cost material, simple design, and easy operation [9]. membrane technology has been increasingly used for removing of heavy metals from waste water and improving water recovery rate because of its main advantage like high removal efficiency and low cost. huge improvements have been made in recent years, and the use of membrane technology has increased in potable water treatment [10]. the most widely used membrane processes for water treatment include micro-filtration (mf), ultra-filtration (uf), nanofiltration (nf), reverse osmosis (ro), and forward osmosis process which is an active process that can effectively remove heavy metals from waste water [11, 12]. the principle of forward osmosis (fo) depends on osmotic pressure gradient generated by high concentration of draw solution (ds) and low concentration of feed solution (fs) to allow water diffuse through semi permeable membrane from fs to ds. the fo process offers the advantages of low operation pressure, high recovery, and low cost and disadvantages of require special membrane, and the membrane need periodically clean [13]. the aim of the present study is to investigate the removal of zn +2 ions from wastewater by adsorption and forward osmosis (fo) methods using tobacco leaves as an adsorbent for adsorption and cellulose triacetate (cta) membrane for forward osmosis and compare the removal efficiency between them. in addition, investigate the parameters that influence the separation efficiency, such as contact time, ph, dose of adsorbent, initial metal concentrations, and concentration of draw solution. also present work aims to determine isotherm model and kinetic models for adsorption system. experimental work materials heavy metal solution zinc chloride (zncl2) has a molecular weight of 136.29 g/mole was used for preparing synthetic solution. to prepare a desired concentration of zn +2 ions, a known quantity of zinc chloride is dissolved in deionized water (di), of 3-8 µs/cm conductivity. solution ph was adjusted (3-7) by adding 0.1 m hcl or 0.1 m naoh as required. mass of heavy metal salt added to water by assuming complete dissolution according to equation below: wtat wtm cvw i . .  …(1) where: w: weight of heavy metal salt (zncl2) (mg), v: volume of solution (l), ci: initial concentration of metal ions (zn +2 ) in solution (mg/l), m.wt: molecular weight of metal salt (zncl2) (g/mole), at.wt: aaomic weight of metal ions (zn +2 ) (g/mole). adsorbent the tobacco leaves are used as adsorbent. the tobacco leaves were washed several times with distilled water to remove all excess and then dried for 24 hr at temperature 60 ºc. the dried tobacco leaves was ground and then sieved to get the particle size of 0.77 mm. the properties of adsorbent are shown in table 1. http://www.iasj.net/ tamara kawther hussein -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 127 table 1: properties of tobacco leaves properties adsorbent (tobacco leaves) ph for (1% sol.) 6.5 moisture content (%) 0.52 sp.gr. for (1% sol.) 1.0026 density @ 15.6 ºc for (1% sol.) 1.0016 viscosity @ 21ºc for (1% sol.) 1.018 draw solution magnesium chloride mgcl2 was dissolved in deionized water of 3-8 µs/cm conductivity, for preparing draw solutions with concentration of 10, 30, 50, 70, 90 and 150 g/l, and then the solutions were mixed by using a stirrer at an agitation speed of 1000 rpm for 15 min. magnesium chloride mgcl2 was used in preparation of draw solutions due to its low molecular weight, dissociated ions number (i = 3), low viscosity, high solubility, high osmotic pressure, non toxic, and easily separated and recycled. table (2) shows the chemical specification of the salt (mgcl2). table 2: chemical specifications of draw solutions magnesium chloride (mgcl2) mw = 95 assay 98% min. max. limits of impurities (%) sulfate 0.002 copper 0.002 lead 0.005 iron 0.0005 zinc 0.0005 apparatus the concentration of the zinc ion was measured by atomic absorption spectrometry (aas) (buck 210/211, u.s.a., perkin elmer, sr.nr:1159a). ph-meter (model 2906, jenway ltd, uk) was used for measuring the ph of metal solution. to measure the concentration of the draw solutions, digital laboratory conductivity meter was used (type : wtw ino lab cond 720 with range (0 2 ×10 6 µs/cm). mechanical stirrer (model: rzr 2021, speed range of 40 2,000 rpm) was used to mixing feed and draw solutions. shaker (hv-2 orbtal, germany) was used for shaking the solutions. a digital balance with 4 decimal points (sartorius bp 3015 max. 303 g, d= 0 -1 mg) was used to measure the weight of feed and draw solutions in experiments. forward osmosis system for forward osmosis process experiments, the cellulose triacetate (cta) membrane (x-pack tm supplied by hydration technology inc., albany, or) was used as flat sheet module. the thickness of cellulose triacetate membrane is less than 50 μm and lacks a thick support layer consist of a woven fabric mesh embedded within a continuous polymer layer. the specific characteristics of the cta membrane module are rejection of salt (95-99 %), and maximum operating temperature 50 ° c. experiments were done using a laboratory-scale forward osmosis system consisting of two cylinders, each one with a capacity of 5 liters were used as vessel of feed and draw solution, two high pressure pumps (flow rate ≥ 0.6 l/ min, 24 vdc, typ 2500, deng yuak) were used to pump feed and draw solutions from vessels to osmosis element. two calibrated flow meters: first one was used to measure the feed solution volumetric flow rate and the second one was used to measure the draw solution volumetric flow rate each of ranged (30 300 l/h). to indicate the feed solution pressure, a pressure gauge (range of 0 2 bar gauge) was used. the forward osmosis cell composed of two semi-cells which were made of teflon. the osmosis cell consisted two channels has dimensions of 12.3 cm length and 12.3 cm width, http://www.iasj.net/ comparative study for removal of zn+2 ions from aqueous solutions by adsorption and forward osmosis 128 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net providing an effective membrane area of 151.2 cm 2 . experimental procedure adsorption process stock solution of zncl2 was prepared by dissolving a known quantity of zncl2 in distilled water and then the solution diluted to the required initial concentration range from (10 to 100 mg/l). a sample of 100 ml of known concentration was added to each flask (250 ml) with a required amount of adsorbent and was shaken at a speed of 200 rpm at 25 ºc for a specified period of contact time, then the metal solution and adsorbent was filtered through a 0.45 μm membrane filter. the metal solution ph was adjusted to the desired ph value. the effect of ph for zn +2 ions removal was studied in ph range of 3 7. effect of initial metal concentrations were conducted using 10, 30, 50, 80 and 100 mg/l metal solutions at temperature 25 °c and optimum ph value. amount of tobacco leaves resin (0.2 5)g were conducted at temperature 25 °c and optimum ph value. to investigate the contact time effect on the adsorption process 1 g of adsorbent dosage was added to 100 ml of 50 mg/l metal solution. the system was subjected to shaking speed of 200 rpm, and the samples were collected from (0 to 220) min to determine the remaining concentration of metal. the final equilibrium concentrations were measured by means of aas. for the remaining metal concentration the filtrate was analyzed. at time t, the amount of zn +2 adsorbed in mg/g was calculated by using equation 2. m vcc q eo e   )( …(2) where: co and ce are initial and equilibrium concentrations of zn +2 ions in the water (mg/l), respectively, v is the volume of the zn +2 solutions in l, m is the weight of tobacco leaves in g. the percentage of removed zn +2 ions (r %) in solution was calculated using equation 3 100 )( (%)    e eo c cc r …(3) forward osmosis process heavy metal waste water (feed solution) and draw solution were placed in cylindrical vessels. the volume of both draw solution (ds) and feed solution (fs) were 2.5 liters and they were run in a closed loop. the outlet valve of the feed vessels was opened to let the whole pipes of the system filled with solutions. the feed solution and draw solution flow tangentially to membrane in a cocurrent flow. this operation provides constant ∆π along the membrane module to make the process more efficient. the streams of feed and draw solution outlet were recycled back to the main vessels. all experiments were done with applying a pressure of 0.25 bar gauge in the feed side across the membrane sheets. the temperature of feed and draw solutions were 25°c, and the volumetric flow rate of both solutions were controlled using calibrated flow meters. the time of experiment was 3 hours. for checking, every 0.5 hour, the increasing in volume of the draw solution (ds) was measured and compared with the reduction in the volume of feed solution (fs). water flux was calculated by dividing the water transported through the membrane by the effective area of cta membrane and the time. measuring of metal concentration in fs outlet was carried out by using aas and measuring of mgcl2 concentration in ds outlet was done by using conductivity meter. figure 1 illustrates the schematic diagram of forward osmosis apparatus. http://www.iasj.net/ tamara kawther hussein -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 129 fig. 1: the schematic diagram of forward osmosis process results and discussion adsorption process effect of contact time the zn +2 ions removal efficiency from waste water was studied as function of contact time. it was found that the zn +2 ions adsorption capacity was higher at the beginning and after that, the adsorption rate became very slow. the degree of adsorption differs because of existence of greater number of adsorbent sites available for the adsorption of metal ions at beginning. the adsorption rate slowed down when the remaining vacant surface sites decreased because of the formation of repulsive forces between the metal ions on the solid surface and in the liquid phase, the same behaviour was observed by [14]. depending on these results 140 min was considered as the optimum time for the rest of the experiments. figure 2 shows the contact time effect on zn +2 ions removal. 0 10 20 30 40 50 60 0 50 100 150 200 250 r e m o v a l e ff ic ie n c y % time, min fig. 2: contact time effect on zn +2 ions removal efficiency using tobacco laves. (ph=5; dosage=1g/100 ml; t=25°c; ci=50 mg/l; speed=200 rpm) effect of ph metal solution the ph is a significant factor affecting the zn +2 ions removal from waste water. at low ph minimum adsorption was observed. this is because of the presence of higher concentration and higher mobility of h + ions. at high h + concentration the surface of the adsorbent becomes more positively charged so that the attraction between adsorbents and metal cations is reduced. but when ph increases, the negatively charged surface area becomes more so greater removal of metal is facilitated and then at very high ph also the percentage of metal removal decreases because that causes precipitation of metal ions on the http://www.iasj.net/ comparative study for removal of zn+2 ions from aqueous solutions by adsorption and forward osmosis 130 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net adsorbent surface by nucleation [15]. ph 5 is the optimum ph used for the zn +2 ions removal for all experiments. figure 3 illustrates the ph effect on zn +2 ions removal efficiencies. 0 10 20 30 40 50 60 70 1 2 3 4 5 6 7 8 r e m o v a l e ff ic ie n c y % ph fig. 3: ph effect on zn +2 ions removal efficiency using tobacco leaves. (t= 140 min; dosage=1g/100 ml; t=25 °c; ci=50 mg/l; speed=200 rpm) effect of tobacco leaves dose the tobacco leaves dose effect on the removal of zn +2 ions was studied using dosages of tobacco leaves. the tobacco leaves adsorbent dose effect on zn +2 ions removal efficiencies is shown in figure 4. when the tobacco leaves adsorbent dose increased up to 1 g/100 ml, the zn +2 ions retention will increase. this value was used as the optimum amount for other trials. it was found that when the amount of adsorbent increased, adsorption of zn +2 ions will increase because of the limited availability of the adsorbing species number for relatively large number of active surface sites on the adsorbent at higher adsorbent dosage. after this dose of adsorbent, the removal efficiency remains unchanged as shown in figure 4. this may be attributed to overlapping of adsorption sites due to overcrowding of tobacco leaves (adsorbent) particles [16]. this appears after a certain adsorbent dose, the maximum adsorption sets in and so the amount of ions (zn +2 ) were bound to the adsorbent and the free ions (zn +2 ) remain constant even with further addition of the adsorbent dose. 0 10 20 30 40 50 60 70 0 1 2 3 4 5 6 r e m o v a l e ff ic ie n c y % dosage , g/100 ml fig. 4: adsorbent amount effect on zn +2 ions removal efficiency using tobacco leaves. (t=140 min; ph=5; t=25 °c; ci=50 mg/l; speed=200 rpm) effect of initial zn +2 ions concentration the increasing in initial zn +2 ions concentration decreases the adsorption percentage removal efficiency. this behaviour is due to that the adsorbent may contain limited exchangeable sites for the certain zn +2 ions concentration range, but when the concentration increase the exchangeable sites in adsorbent will not be enough to accumulate this concentration so the removal percentage will decrease. at lower zn +2 ions concentration, the percentage uptake increases due to larger active surface adsorbent area available for adsorption [17]. figure 5 illustrates the effect of initial concentration of zn +2 ions on removal efficiency. 0 10 20 30 40 50 60 70 80 0 20 40 60 80 100 120 r e m o v a l e f f ic ie n c y r % ci, mg/l fig. 5: initial concentration effect on zn +2 ions removal efficiency using tobacco leaves. (ph=5; dosage=1g/100 ml; t=25°c; t= 140 min; speed=200 rpm) http://www.iasj.net/ tamara kawther hussein -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 131 adsorption isotherms models adsorption isotherms models are very significant tools for the analysis of adsorption process. the adsorbent unit mass at constant temperature is decided the relationship between the equilibrium concentration and amount of adsorbate adsorbed [18]. langmuir and freundlich isotherm model are widely used to investigate the process of adsorption. langmuir isotherm model langmuir isotherm model shows that the adsorption occurs on the homogenous surfaces by adsorption of monolayer without interaction between adsorbed molecules [19]. the model describes by the equation 4: el elm e ck ckq q   1 …(4) where kl is the langmuir constant related to the adsorption capacity (l/mg), qe is the amount of zn +2 ions adsorbed on the surface of biomass at the equilibrium (mg/g), ce is the equilibrium of zn +2 ions concentration in the solution (mg/l), and qm is the maximum capacity of adsorption for zn +2 ions adsorbed on the surface of biomass (mg/g). from figure 6 the adsorption parameters (qm, kl) can be determined from the intercept and slop plotting ce/qe vs. ce, equation 5 and table 3 illustrate these parameters. m e lme e q c kqq c  1 …(5) y = 0.091x + 3.962 r² = 0.986 0 1 2 3 4 5 6 7 8 9 0 10 20 30 40 50 c e /q e ce fig. 6: langmuir isotherm for adsorption of zn +2 ions on tobacco leaves. (ph=5; t=25 °c; dosage=1g/100 ml; t=140 min; speed=200 rpm) freundlich isotherm model freundlich equation is the model of multilayer adsorption and the adsorption on the heterogeneous surface [20]. the equation of freundlich is: n efe ckq /1  …(6) a linear form of freundlich, equation 6 is: fee kcnlogq loglog)/1(  …(7) where ce and qe are as mentioned before, kf is freundlich constant which shows the relative adsorption capacity of the adsorbent (mg/g), and n is freundlich constant and refers to the adsorption intensity. if 1/n approaches 1, the equation becomes linear. if 1/n value is within 0.1 and 1, it shows a suitable adsorbate adsorption on the given adsorbent. the values kf and n can be determined from the intercept and slope plotting of experimental data of log qe versus log ce respectively as shown in figure 7 and table 3. the correlation coefficient (r 2 ) values got from langmuir isotherm is 0.986 and from freundlich isotherm is 0.99 for zn +2 ions adsorption on to tobacco leaves so freundlich isotherm represents a better adsorption than langmuir isotherm. y = 0.768x 0.490 r² = 0.990 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1 0 0.5 1 1.5 2 l o g q e log ce fig. 7: freundlich isotherm for adsorption of zn +2 ions on tobacco leaves. (ph=5; t=25 °c; dosage=1g/100 ml; t=140 min; speed=200 rpm) http://www.iasj.net/ comparative study for removal of zn+2 ions from aqueous solutions by adsorption and forward osmosis 132 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net table 3: langmuir and freundlich isotherm parameters for zn +2 ions adsorption onto tobacco leaves langmuir qm(mg/g) kl(l/mg) r 2 10.989 0.0229 0.986 freundlich kf(mg/g) 1/n r 2 3.090 0.768 0.990 adsorption kinetics models adsorption kinetics study the solute uptake rate which in turn determines the resident time reaction [21]. to be able to predict the mechanism which involved in the adsorption process different kinetic models have been used by several researchers. these contain pseudofirst-order model, pseudo-second-order model are widely used [19, 22]. pseudo first-order kinetic model the liquid-solid phase adsorption kinetic process is explained by simple linear equation for pseudo first order reaction kinetic [23]. it can be shown as follows [24]: )( 1 te t qqk dt dq  …(8) where qe is the amount of zn +2 ions adsorbed on adsorbent dose surface at equilibrium (mg/g) and qt is the amount of zn +2 ions adsorbed on adsorbent dose surface at time t (min), respectively. k1 is the constant of pseudo-first-order adsorption rate (min 1 ). by integrating equation 8 with the boundary conditions qt=0 at t=0 and qt = qt at t=t, then equation 8 becomes: t k qqq ete  303.2 log)log( 1 …(9) by plotting log (qe-qt) against t, the values of pseudo-first-order rate constant (k1 , qe) are determined from the slope and intercept as shown in figure 8. y = -0.004x + 0.542 r² = 0.947 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 0 40 80 120 160 lo g (q e -q t ) t , min fig. 8: pseudo first order test for the zn +2 ions adsorption on tobacco leaves (ph=5; dosage=1g/100 ml; speed= 200 rpm; t= 25°c, ci= 50 mg/l) pseudo-second-order kinetic model pseudo second order reaction kinetic showed the adsorption kinetic process of divalent metal ions onto natural adsorbents [25]. the pseudosecond order kinetic rate is shown in equation 10 [26]. 2 2 )( te t qqk dt dq  …(10) where k2 is the constant of pseudosecond-order adsorption rate, (g/mg min). then after integration and applying boundary conditions qt=0 at t=0 and qt = qt at t=t; the equation 10 becomes: tk qqq ete 2 1 )( 1   …(11) equation 11 is rearranged to obtain equation 12 in linear form: t qqkq t eet 11 2 2  …(12) the values (k2, qe) can be obtained from the slope and intercept by plotting t/qt against t as shown in figure 9. http://www.iasj.net/ tamara kawther hussein -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 133 y = 0.177x + 36.07 r² = 0.576 0 10 20 30 40 50 60 70 0 40 80 120 160 t/ q t t, min fig. 9: pseudo second order test for the zn +2 ions adsorption on tobacco leaves (ph=5; dosage=1g/100 ml; speed= 200 rpm; t= 25°c, ci= 50 mg/l) the correlation coefficient values (r 2 ) show a good fit of pseudofirst -order model with the experimental data compared to pseudosecond -order model. between the qe,exp and qe ,cal there is only a little difference as shown in table 4. therefore, the first-order model can be applied for zn +2 ions adsorption process. table 4: comparison of adsorption rate constants, experimental and calculated qe values for the pseudo-firstand –second-order reaction kinetics for removal of zn +2 ions by tobacco leaves pseudofirst order qe. exp (mg g -1 ) k1 ×10 -3 (min -1 ) qe, cal (mg g -1 ) r 2 3.15 9.212 3.483 0.947 pseudosecond order qe, exp (mg g -1 ) k2 ×10 -3 (min -1 ) qe, cal (mg g -1 ) r 2 3.15 2.792 5.649 0.576 forward osmosis process effect of draw solution concentration increasing the draw solution concentration (cd) caused increasing the water flux due to an increase in driving force and water transport through the membrane. these observations are well agreed with the results of [27]. in the fo process as the feed solution is placed at the active layer of the membrane and draw solution is placed at the support layer of the membrane, with time the water flux decreased and reached the steady state after 3 h due to decreasing in driving force for water transport through the membrane and increasing in dilution of the draw solution, these results are well agreed with the results of [28], the results as shown in figure 10. 15 40 65 90 115 140 165 0 0.5 1 1.5 2 2.5 3 3.5 j , l /m 2 .h time,h conc=10 g/l conc=30 g/l conc=50 g/l conc=70 g/l conc=90 g/l conc=150 g/l fig. 10: water flux with time at different mgcl2 concentration (cd) (zn +2 concentration = 50 mg/l, temp. of fs & ds = 25 o c, ph of feed = 5, qd = 40 l/h, qf = 40 l/h, and p = 0.25 bar) effect of zinc concentration in feed solution figure 11 shows the effect of different feed solution concentration (cf) (zn +2 ) on water flux with time. the amount of the permeate water flux decreased when the zn +2 ions concentration increased with the time due to increase in the osmotic pressure of feed solution and leads to reducing the overall driving force (high osmotic pressure of ds – low osmotic pressure fs) for water transport through the membrane. this conclusion corresponds with the results of, [29]. 15 35 55 75 95 115 135 0 0.5 1 1.5 2 2.5 3 3.5 j , l/ m 2 .h time, h conc=10 mg/l conc=30 mg/l conc=50 mg/l conc=80 mg/l conc=100 mg/l fig. 11: water flux with time at different zn +2 concentration in feed solution (mgcl2 concentration = 30 g/l, temp. of fs & ds =25 o c, ph of feed =5, qd = 40 l/h, qf =40 l/h, and p = 0.25 bar) http://www.iasj.net/ comparative study for removal of zn+2 ions from aqueous solutions by adsorption and forward osmosis 134 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net effect of zinc feed solution ph in forward osmosis process, ph effect on the permeate flux with time as shown in figure 12. lowering the ph of feed solution leads to increase the solubility of dissolved salt and decrease the rate of zinc salt scaling on the membrane surface, this lead to decrease the feed solution osmotic pressure and increase the water flux [30]. but increasing the feed solution ph leads to accelerate the zinc salt deposition on the membrane surface and causes concentrative external concentration polarization (ecp) on the membrane, this leads to decrease the water flux with time. this behaviour in agreement with [31]. 10 30 50 70 90 110 130 0 0.5 1 1.5 2 2.5 3 3.5 j , l /m 2 .h time, h ph=4 ph=5 ph=6 ph=7 fig. 12: water flux with time at different ph of zn +2 feed solution (mgcl2 concentration = 30 g/l (zn +2 concentration = 50 mg/l, temp. of fs & ds = 25 o c , qd = 40 l/h, qf = 40 l/h, and p = 0.25 bar) concentration of feed solute in permeate and membrane rejection percentage (r %) figure 13 illustrates concentration of zinc salt in permeate increased and rejection percentage (r %) of zinc salt decreased with increasing in operating time. increasing in concentration of zinc metal decreases rejection percentage with the time due to formation of zinc layer on the surface of membrane retarding the back diffusion of the zinc salt from the membrane surface back to the bulk solution. consequently, a larger concentration of zinc metal is created and it is prepared for its diffusion across the cta membrane and this observation agree with, [32]. 0 5 10 15 20 25 30 35 0 0.5 1 1.5 2 2.5 3 3.5 4 c z n + 2 i n p e r m it e , m g /l time, h conc=10 mg/l conc=30 mg/l conc=50 mg/l conc=80 mg/l conc= 100 mg/l (a) 65 70 75 80 85 90 95 100 0 0.5 1 1.5 2 2.5 3 3.5 4 r % time, h conc=10 mg/l conc=30 mg/l conc=50 mg/l conc=80 mg/l conc=100 mg/l (b) fig. 13: effect of time on (a) product zn +2 ions concentration (b) rejection percentage (r %) at different zn +2 concentration in feed solution. experimental condition : mgcl2 concentration = 30 g/l, temp. of fs & ds = 25 o c, ph of feed =5, qd = 40 l/h, qf =40 l/h, and p = 0.25 bar comparation between adsorption and forward osmosis process table 5 shows that forward osmosis process is an excellent process for removal of zn +2 ions from wastewater with removal efficiency percentage 96.2 % compared with the adsorption process with removal efficiency percentage 70 %. figure 14 shows the comparison of the rejection percentage (r%) between adsorption and forward osmosis. http://www.iasj.net/ tamara kawther hussein -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 135 table 5: comparison the rejection percentage (r%) between adsorption and forward osmosis at different inlet concentration of zinc solution initial zinc conc. adsorption (r %) forward osmosis (r %) (after 3hr) 10 70 96.22 30 68 90.423 50 63 84.202 80 60 76.282 100 55 67.009 50 60 70 80 90 100 0 20 40 60 80 100 120 r % czn+2initial, mg/l adsorption forward osmosis fig. 14: comparison the rejection percentage (r %) between adsorption and forward osmosis (forward osmosis process, mgcl2 concentration = 30 g/l, temp. of fs & ds = 25 o c, ph of feed =5, qd = 40 l/h, qf =40 l/h, and p = 0.25 bar, adsorption process, ph=5; dosage= 1g; t=25°c; t= 140 min; speed=200 rpm) conclusions 1the adsorption studies showed that the adsorbent (tobacco leaves) is effective for the zn +2 ions removal from aqueous solutions. 2it was found that maximum adsorption occur at optimum contact time 140 min, optimum ph 5, and optimum dose of adsorbent about 1g/100 ml. 3removal percentage of zn +2 ions was decreased with increasing the concentration. 4freundlich isotherm model give best fit to experimental data in comparison with langmuir isotherm model, and in addition that zn +2 ions adsorption followed pseudo-first -order kinetics. 5the water flux produced from the forward osmosis cell increased when the concentration of draw solution increased and decreased when the concentration of feed solution increased and ph of zinc solution increased. 6the water flux produced from the forward osmosis decreased with the time and reached the steady state after 3 h. 7it was found the removal efficiency for zn +2 ions by forward osmosis is 96.2 % better than the removal efficiency by adsorption 70%. nomenclature a.wt atomic weight (g/mole) co initial concentration (mg/l) cd concentration of draw side (g/l) ce equilibrium of zn +2 ions concentration in the solution (mg/l) cf concentration of feed side (mg/l) cp product concentration (mg/l) j water flux (l/m 2 .h) k1 constant of pseudo first-order adsorption rate (min -1 ) k2 constant of pseudo-second -order adsorption rate (g/mg. min) kf freundlich constant (-) kl langmuir constant related to the adsorption capacity (l/mg) m.wt molecular weight (g/mole) m amount of resin (g) n freundlich constant (-) qe amount of adsorbate adsorbed on the surface of biomass at the equilibrium (mg/g) qm maximum capacity of adsorption for zn +2 ions adsorbed on the surface of biomass (mg/g) qt amount of zn +2 ions adsorbed on adsorbent dose surface at time t (min) r rejection percentage (%) t time (hr) t temperature (°c) v volume of solution (l) w weight of metal solute (mg) references 1. nocito, f. f., lancilli, c., giacomini, b., and sacchi, g. a., 2007, "sulfur metabolism and cadmium stress in higher plants", http://www.iasj.net/ comparative study for removal of zn+2 ions from aqueous solutions by adsorption and forward osmosis 136 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net plant stress, global science books, vol. 1, no. 2, p. 142-156. 2. meroufel1, b., benali, o., benyahia, m, zenasni, m. a., merlin, a., and george, b., 2013, "removal of zn (ii) from aqueous solution onto kaolin by batch design", journal of water resource and protection, vol.5, p. 669-680 3. hubicki, z., and kolodynska, d., 2012, "selective removal of heavy metal ions from waters and waste waters using ion exchange methods", maria curiesklodowska university, poland 4. chigondo, f., nyamund, b. c., sithole, s. c., and gwatidzo, l., 2013, "removal of lead (ii) and copper (ii) ions from aqueous solution by baobab (adononsia digitata) fruit shells biomass", iosr journal of applied chemistry (iosr-jac), vol. 5, no.1, p. 4350. 5. abas, s. n. a., ismail, m. h. s., kamal, m. l., and izhar, s., 2013, "adsorption process of heavy metals by low-cost adsorbent: a review", world applied sciences journal, vol. 28 no. 11, p. 15181530. 6. doss, v. r., and kodolikar, s. p., 2012, "heavy metal adsorption by ligand loaded granular activated carbon : thermodynamics and kinetics", international journal of environmental sciences, vol. 2, no. 4, p. 21262142. 7. kumar, u., and bandyopadhyay, m., 2006, "sorption of cadmium from aqueous solution using pretreated rice husk", journal of biores. technol., vol. 97, p. 104109. 8. jogi, m. m., and ansari, i. a., 2003, "non-conventional utilization of maize husk for the removal of iron from industrial wastewater", journal of biosci. & biotechnol. res. asia, vol.1, no. 1,p. 63-66. 9. saeed, h., rashid, z., chaudhry, f. s., aziz, a., ijaz, a., and awan, j. a., 2016, "removal of toxic heavy metallic ions cr (vi), cu (ii), ni (ii), co (ii) andcd (ii) from waste water effluents of tanneries by using oryza sativa (rice) husks", sci.int.(lahore), vol. 28, no. 1, p. 401-406. 10. raval, h. d., and koradiya, p., 2015, "direct fertigation with brackish water by a forward osmosis system converting domestic reverse osmosis module into forward osmosis membrane element", desalination and water treatment, p. 1-8. 11. yue, c., qingchun, g., xiang, y. l., and tai-shung, c., 2014, "novel forward osmosis process to effectively remove heavy metal ions", journal of membrane science, vol. 467, p.188–194 12. petr, m., and jiří, c., 2016, "removal of heavy metal ions from aqueous solutions by nanofiltration", chemical engineering transactions, vol.14, p. 379-384. 13. chekli , l., phuntsho, s., kim, j. e., kim, j., choi, j. y., choi, j. s., kim, s., kim, j. h., hong, s., sohn, j., and shon, h. k., 2016, "a comprehensive review of hybrid forward osmosis systems: performance, applications and future prospects", journal of membrane science, vol. 497, p. 430–449. 14. saeed, h., chaudhry, f. s., rehman, s., rashid z., ijaz, a, and awan, j. a., 2016, "removal of toxic metallic ions cr(vi), cu(ii), ni(ii), co(ii) and cd(ii) from waste water effluents of tanneries by using punica granatum (pomgranate) membrane", iranica journal of http://www.iasj.net/ tamara kawther hussein -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 137 energy and environment, vol. 7, no.1, p. 52-57, 15. onundi, y. b., mamun, a. a., al khatib, m. f., and ahmed, y. m., 2010, "adsorption of copper, nickel and lead ions from synthetic semiconductor industrial wastewater by palm shell activated carbon", int. j. environ. sci. tech., vol 7, no 4, p. 751-758. 16. heidari, a., younesi, h., and mehraban, z., 2009, "removal of ni (ii), cd (ii), and pb(ii) from a ternary aqueous solution by amino functionalized mesoporous and nano mesoporous silica", chem. eng. j. vol. 153, p. 70–79. 17. luo, j., shen, h., markstrom, h., wang, z., and niu, q., 2011, "removal of cu +2 from aqueous solution using fly ash", journal of minerals & materials characterization & engineering, vol. 10, no. 6, p. 561-571. 18. sevgi k., 2007, "comparison of amberlite ir120 and dolomite performances for removal of heavy metals", journal of hazardous materials, vol. 147, p. 488-496. 19. ahmad, i., ahmad, f., and pichtel, j., 2011, "microbes and microbial technology: agricultural and environmental applications", springer, new york. 20. zhihui yu, tao q., jingkui q., lina w., and jinglong c., 2009, "removal of ca (ii) and mg (ii) from potassium chromate solution on amberlite irc784 synthetic resin by ion exchange", journal of hazardous materials, vol. 7, no. 2, p.395-399. 21. ahmed, a. j.,balakrishunan, v., and arivoli, s., 2011, "kinetic and equilibrium studies on the adsorption of cu(ii) ions by a new activated carbon", european journal of experimental biology, vol.1, p. 23-37. 22. pehlivan, e., and altun, t., 2007, "ion exchange of pb +2 , cu +2 , zn +2 , cd +2 ,and ni +2 from aqueous solution by lewatit cnp 80", journal of hazardous materials, vol. 140, p. 299 – 307. 23. lagergren, s., 1989, "about the theory of so-called adsorption of soluble substances", kung seventeen hand, vol. 24, p.1–39. 24. sen, t. k. and sarzali, m. v., 2008, "removal of cad-mium metal ion (cd +2 ) from its aqueous solution by aluminium oxide: a kinetic and equilibrium study", chemical engineering journal, vol. 142, p. 256-262. 25. ho, y. s., and mckay, g., 1999, "pseudo-second order model for sorption processes", process biochem, vol. 34, no., p.451–465. 26. arias, f., and sen, t. k., 2009, "removal of zinc metal ion (zn +2 ) from its aqueous solution by kaolin clay mineral: a kinetic and equilibrium study", colloids and surfaces a, vol. 348, p. 100-108. 27. jincai, s., tai-shung, c., bradley, j. h., and jos, s. d. w., 2013, "understanding of low osmotic efficiency in forward osmosis: experiments and modeling", desalination, vol. 313, p. 156-165. 28. al-alawy, a. f., omran, i. i., and makki, h. f., 2015. "forward osmosis process as an alternative method for the biological treatment of wastewater from the al-za'afaraniya tanning factory", the international journal of science &technoledge (issn 2321 – 919x), vol.3, p. 159-170. 29. qin, j. j., danasamy, g., lay, w. c. l. , and kekre, k. a., 2013, "challenges in forward osmosis of seawater using ammonium bicarbonate as osmotic agent", american journal of water resources, vol. 1, no. 3, p. 51-55. http://www.iasj.net/ comparative study for removal of zn+2 ions from aqueous solutions by adsorption and forward osmosis 138 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net 30. abid, m. f., zablouk, m. a. and abid-alameer, a. m., 2012, "experimental study of dye removal from industrial wastewater by membrane technologies of reverse osmosis and nanofiltration", iranian journal of environmental health science & engineering, p.1-9. 31. changwon, s., and seockheon, l., 2013, "modeling reverse draw solute flux in forward osmosis with external concentration polarization in both sides of the draw and feed solution", journal of membrane science, vol. 427, p. 365-374. 32. changwoo, k., sangyoup, l., ho, k. s., menachem, e., seungkwan, h., 2012, "adsorption boron transport in forward osmosis: measurements, mechanisms, and comparison with reverse osmosis", journal of membrane science, vol. 419-420, p. 42-48. http://www.iasj.net/ removal of manganese ions (mn2+) from a simulated wastewater by electrocoagulation/ electroflotation technologies with stainless steel mesh electrodes: process optimization based on taguchi approach available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.20 no.1 (march 2019) 39 – 48 eissn: 2618-0707, pissn: 1997-4884 corresponding author: rasha h. salman, e-mail: rasha.habeeb@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. removal of manganese ions (mn 2+ ) from a simulated wastewater by electrocoagulation/ electroflotation technologies with stainless steel mesh electrodes: process optimization based on taguchi approach rasha h. salman chemical engineering department – college of engineering – university of baghdad abstract this study depicts the removal of manganese ions (mn 2+ ) from simulated wastewater by combined electrocoagulation/ electroflotation technologies. the effects of initial mn concentration, current density (c.d.), electrolysis time, and different mesh numbers of stainless steel screen electrodes were investigated in a batch cell by adopting taguchi experimental design to explore the optimum conditions for maximum removal efficiency of mn. the results of multiple regression and signal to noise ratio (s/n) showed that the optimum conditions were mn initial concentration of 100 ppm, c.d. of 4 ma/cm 2 , time of 120 min, and mesh no. of 30 (wire/inch). also, the relative significance of each factor was attained by the analysis of variance (anova) which indicates that the percentage of contribution followed the order: time (47.42%), c.d. (37.13%), mesh number (5.73%), and mn initial conc. (0.05%). the electrolysis time and c.d. were the most effective operating parameters and mesh no. had a fair influence on mn removal efficiency, while the initial conc. of mn. had no significant effect in the studied ranges of control factors. regression analysis (r 2 = 90.16%) showed an acceptable agreement between the experimental and the predicted values, and confirmation test results revealed that the removal efficiency of mn at optimum conditions was higher than 99%. keywords: mn removal, electrocoagulation, electroflotation, stainless steel electrodes, screens electrodes, wastewater, taguchi method received on 04/02/2019, accepted on 25/02/2019, published on 30/03/2019 https://doi.org/10.31699/ijcpe.2019.1.6 1introduction heavy metals from various economic activities can be considered as very influential toxic agents. due to their great solubility and low biodegradability in the aquatic environments, aqueous solutions, and many industrial wastewaters, the presence of these components even at low concentrations causes deterioration of many ecosystems and particularly human health. further, heavy metals lead to serious environmental pollution ‎[1], ‎[2]. industries including mining, electro-plating or melting operations are developed rapidly. wastewaters discharged into the environment from these industries holding excessive concentrations of toxic metals (e.g. mn, cd, zn, and cu), so destructive effects on the organism life would take place if no handling arise ‎[3], ‎[4]. the abundance of manganese (mn) metal in nature is very high and it is considered as a vital metal for the human system but with trace amounts due to its ability in enzymes activation. it is used widely in many applications like primary cells, alloys industry, ceramics, and electrical coils besides its presence naturally in the atmosphere as suspended particulates due to its disposal from different sources like industrial emission and soil erosion ‎[5]. several techniques were employed for the pollution abatement of heavy metal ions in wastewater which include: adsorption ‎[6], chemical precipitation ‎[7], ionexchange ‎[8], biosorption ‎[9], membrane filtration ‎[10], coagulation-flocculation ‎[11], and flotation ‎[12]. many of these techniques have disadvantages. for example, precipitation can be considered as the most economical valid, but additional treatment is required due to the production of precipitate sludge. reverse osmosis, ion-exchange, and other membrane separation techniques can efficiently be used in metal ions removal, but there are limitations in the use of these techniques like high material, and functional cost. in addition to their operative problems, these disadvantages, together with the requirement of effective low-cost treatment, have created innovative challenges for these technologies ‎[13]. electrocoagulation (ec) is not a new technology but it is an eco-friendly process. in this technique, there are no chemicals added as in the chemical coagulation process. https://doi.org/10.31699/ijcpe.2019.1.6 r. h. salman/ iraqi journal of chemical and petroleum engineering20,1 (2019) 39-48 04 so, there is no problem of neutralizing excess chemicals and no probability of secondary contamination initiated by chemical substances that added at high concentration. ec technique also has many advantages include: producing effluent with a less total dissolved solids content (tds), demanding simple equipment and it is easy to operate, producing a clear, odorless and colorless discharge. besides, low amount of sludge is formed in this technique which consists mainly of metallic oxides/hydroxides which tend to be readily settable and easy to be removed. also, the smallest colloidal particles can be removed by this technique due to the fast motion resulted from the applied electric field that facilitating the coagulation ‎[4],‎[14], ‎[15]. the high effectiveness of the ec process in the elimination of heavy metal ions from industrial/synthesis wastewater has been proved by several studies ‎[5], ‎[16]–‎[19]. electrocoagulation/electroflotation (ecf) is an electrochemical process in which the wastewater would be subjected to a direct current (dc) field. so, in-situ generation of coagulants by electro-dissolution of a soluble sacrificial anode dipped in the wastewater would take place. the most sacrificial anodes are al and fe. solid flat electrodes are traditionally used, but in some previous studies, cylindrical perforated ones are implemented due to better dispersal of the applied dc field onto the wastewater to be handled ‎[20], ‎[21]. the ecf has often been considered for the wastewater treatment and it has a wide area of application, for example, heavy metals, organic chemicals, oil, textile effluents, specific organics, turbid effluent, petroleum industry, suspended particles of all sorts, fluoride, nitrate, and arsenic ‎[22]. there are complex chemical and physical changes that commonly take place in any electrocoagulation process. when a direct current or voltage is applied, positive ionic coagulants would be formed due to sacrificial anodes oxidation. consecutively, generation of hydroxyl ions (oh ) and some o2 and h2 gas bubbles would take place due to water reduction arising at the cathode. the formed ions is migrated to oppositely charged electrodes so destabilization of the contaminants and the particulate suspension would take place because of this movement leading to break down the emulsion. metallic hydroxides of good adsorption properties would be formed because of interaction between the positive ion (al 3+ or fe 2+ ) and the hydroxyl ion (oh ), that are capable of destabilizing any dispersed particles existing in the wastewater. larger aggregates formed because of adsorption of pollutants into the hydroxide structures ‎[2], ‎[15]. the formed aggregates can be carried by flotation of hydrogen and oxygen bubbles which move upwards in the liquid phase where it can be more easily concentrated, collected and removed or can be precipitated if they have a quite high density in comparison with the medium ‎[2], ‎[15]. at the anode, anodic dissolution of stainless steel electrode takes place beside water oxidation to produce oxygen gas and hydrogen ions. at the cathode, generation of hydroxyl ion (oh ) and hydrogen gas occur due to water reduction and these hydroxyl ions would react with fe ions to produce fe(oh)2. the chemical reactions can be illustrated as follows ‎[1], ‎[14], ‎[21]: at the anode: (1) ( ) + (2) at the cathode: (3) in the solution: (4) however, fe 3+ ions can be generated in the presence of oxygen and at acidic ph, and many species can be existing in the electrolytic solution as represented in the following reactions ‎[1]: (5) (6) also, fe(oh)3 and fe(oh) − 4 can exist in the electrolytic solution in more amount under alkaline conditions. it is stated that fe(3 + ) hydroxide coagulants have higher activity than fe(2 + ) hydroxide due to the higher stability of fe(oh)3. so, the presence of these species gives an enhancement to the ecf process. in this case, the overall electrochemical reaction is ‎[1]: (7) there are several previous studies deals with manganese ions removal from wastewater ‎[23]–‎[25], however, there is a dramatic lack of results in case of applying different mesh no. of stainless steel screen electrodes in ecf process. the objective of this research is to examine the removal of mn ions by ecf technique using taguchi experimental design with l18 orthogonal array to optimize the parameters and analyze them successively. also, the effect of the controllable parameters on the removal efficiency of mn ions was determined, and the optimization was accomplished by applying the standard procedure proposed by the taguchi to attain maximum mn ions elimination. four effective parameters that have a high influence on the removal efficiency were studied: mn initial concentration, current density, time, and finally mesh number which has not been satisfactorily considered in previous studies. a confirmation experiment was also accomplished at the optimized conditions. 2experimental work 2.1. materials and system in each batch ecf experiment, 1.5 l of a simulated aqueous solution was prepared. distilled water was used in the preparation of the simulated aqueous solution and all chemicals were of the reagent grade. r. h. salman/ iraqi journal of chemical and petroleum engineering20,1 (2019) 39-48 04 the reagents used were as follows: manganese sulfate (mnso4.h2o, 99 %), sodium dodecylsulfate (sds) as a collector in a stoichiometric ratio of 1:1, ethyl alcohol (c2h5oh, 0.1 vol. %) as ph regulators and bubbly agent, and sodium sulfate (na2so4, 99.5 %) for preparing 0.1 m supporting electrolyte which used for growing the ionic strength, reducing the resistance between the electrodes, decreasing the oxide layer formation on the electrode which prevents or minimize the release of different ions from electrodes into the polluted solution. ph for all experiments was adjusted at 7.5. the ecf batch experiments have been conducted in a glass cell (17×12×14 cm) placed on a magnetic stirrer hot plate (jenway, model 1000) at 250 rpm. fig. 1 shows a scheme of the experimental apparatus. two stainless steel woven wire mesh electrodes (10×10 cm) were used as anode and cathode that fixed on a handmade acrylic frame (10.5×10.5 cm) with (l) shape. the vertical part of this frame is firmed on the edge of the cell, while the horizontal part is perforated with 42 holes (0.5 cm). the cathode is firmed at the top while anode at the bottom, the distance between the two electrodes was 1 cm. both electrodes were connected to a dc power supply (uni-t: utp3315tf-l). prior to each experiment, the electrodes were rinsed with hno3 solution (1m) in an ultrasound cleaner and then washed carefully with double-distilled water. all experiments were carried out at the laboratory temperature and performed in duplicate and the average value of the removal percentage (re%) was taken. to follow the progress of ecf experiments, samples were taken before each experiment and at the end. the final sample was filtered using whatman filter paper (0.15µm) to exclude the sludge generated throughout electrolysis or centrifuged if necessary. the residual concentration of mn was measured by atomic absorption spectroscopy (varian spectraa 200 spectrometer). removal efficiency can be expressed as ‎[26]: (8) where: c0 and cf represent the initial and final concentration of manganese ions in ppm respectively. fig. 1. a schematic photo of ecf cell three types of 316-aisi stainless steel screens were used with mesh numbers 18, 24, 30 wire/inch. for each screen, the porosity ( ) was estimated by applying eq. (9) ‎[27]: (9) where the weight/area ratio ( of the screen was equal to 0.1334, 0.1334, and 0.1237 (g/cm 2 ) for the three screens respectively, the screen thickness equal to (l=2d), and the density of 316-aisi stainless steel is 8.027 (gm/cm 3 ) ‎[27]. the diameter (d) of the wire of each screen was measured by digital caliper, and they were 0.04, 0.034, and 0.03 cm for the three screens respectively. while the woven type of the screen was identified by using an olympus bx51m with dp70a digital camera system and it was plain square. the porosity values for the three screens were 0.7907, 0.7538, and 0.7146 respectively. then the specific surface area ( ) was estimated by eq. (10) ‎[27]: (10) where, r is the ratio of surface to volume of the wire forming the screen and it is equal to (4/d), and the calculated specific surface area was equal to be 20.93, 28.964, and 38.055 cm -1 for the three screens respectively. 2.2. design of experiments (doe) an operative method for the analyzing of experimental results of a study and evaluating the distinct contribution of controlling parameters on the objective functions can be obtained by applying doe methods based on the statistical techniques. moreover, process optimization, cost minimization, quality enhancement as well as the provision of strong design solutions can be achieved by these methods. taguchi optimization technique is known as a robust, distinctive, and prevailing optimization discipline that permits optimization with a minimum number of experiments ‎[28], ‎[29]. there are many previous studies deals with the investigation of removal of different pollutants from wastewater by applying taguchi optimization method ‎[30]–‎[35]. taguchi design of experimental technique was used in this study to detect the most controlling parameters on mn ions removal, minimize the number of experiments, optimize the four studied parameters, and obtain the optimal operating conditions for mn ions removal which have a prevailing influence on the performance of ecf process. r. h. salman/ iraqi journal of chemical and petroleum engineering20,1 (2019) 39-48 04 four factors were investigated in this present study: initial concentration of mn (coded a) with two levels (100, 50 ppm) corresponding to levels 1 and 2; the other factors with three levels were current density (coded b) (20, 30, 40 ma/cm 2 ), electrolysis time (coded c) (40, 80, 120 min), and mesh number (coded d) (18, 24, 30 wire/inch) corresponding to levels 1, 2, and 3. according to the taguchi experiment design, the suitable orthogonal array which allows studying the influence of the considered parameters and the interaction between them for these mixed levels would be l18 either (3 3 × 2 1 ) array that presented in table 1 and the experiments were conducted according to these conditions. table 1. coded values of l18 orthogonal array exp. no. coded values a b c d 1 1 1 1 1 2 1 1 2 2 3 1 1 3 3 4 1 2 1 1 5 1 2 2 2 6 1 2 3 3 7 1 3 1 2 8 1 3 2 3 9 1 3 3 1 10 2 1 1 3 11 2 1 2 1 12 2 1 3 2 13 2 2 1 2 14 2 2 2 3 15 2 2 3 1 16 2 3 1 3 17 2 3 2 1 18 2 3 3 2 consequently, an analysis of the signal-to-noise (s/n) ratio is needed for assessing the experimental results. in taguchi technique, the performance characteristics (s/n) are performed into three options: “larger is the better (lb)”, “nominal the-best (nb)”, and “smaller-the-better (sb)”. the highest mn ions removal percentage (re%) was the objective of this study, therefore the larger is the better criteria was implemented for the present study. the s/n ratio with lb characteristics can be performed as in eq. (11) ‎[36], ‎[37]: ∑ ] (11) where n is the number of repetitions under the same experimental conditions, and yi is the performance results of the ith experiment. minitab 17 software was used for analyzing the experimental data. 3results and discussion 3.1. optimization and the signaltonoise analysis the investigation of the relationship between removal percentage of mn ions and the controllable factors can be obtained by multiple linear regression equation which was developed by using minitab 17 software. the mathematical model for mn ions removal percentage through the statistical analysis is given by eq. (12) (with the correlation coefficient r 2 being equal to 90.16%, which implicates a good fitting of the model): (12) table 3 shows the experimental and predicted values of the l18 orthogonal array for mn ions removal percentage. table 2 also shows the response calculated based on eq. (12) which represents the predicted values of re% and the s/n ratios that determined based on eq. (11) for all the responses of experiments. fig. 2 shows the comparison between the experimental results and the predicted results based on eq. (12). it is obvious that the model predicts reasonably well for mn ions removal and eq. (12) can be considered as a good tool for process assessment. fig. 2. comparison between experimental and predicted re% values of mn removal 0 20 40 60 80 100 120 1 3 5 7 9 11 13 15 17 r e % exp. no. experimental re% predicted re% r. h. salman/ iraqi journal of chemical and petroleum engineering20,1 (2019) 39-48 04 table 2. experimental and predicted values of re% and s/n ratios results of all experiments exp . no. real values exp. predicted s/n ratio mn conc. (ppm) c.d. (ma/cm 2 ) time (min) mesh number (mm) 1 100 20 40 18 62.34 60.55 35.7609 2 100 20 80 24 71.20 69.03 36.8105 3 100 20 120 30 89.20 85.87 38.5413 4 100 30 40 18 67.98 71.85 37.0369 5 100 30 80 24 75.49 80.33 38.0865 6 100 30 120 30 95.94 97.17 39.8172 7 100 40 40 24 78.41 77.75 37.7845 8 100 40 80 30 97.30 91.50 39.2318 9 100 40 120 18 92.87 96.68 39.7352 10 50 20 40 30 62.96 66.07 36.4151 11 50 20 80 18 65.86 68.16 36.6351 12 50 20 120 24 77.85 79.73 37.9682 13 50 30 40 24 78.26 71.73 37.1494 14 50 30 80 30 82.67 85.47 38.5967 15 50 30 120 18 96.87 90.66 39.1002 16 50 40 40 30 80.90 82.90 38.2947 17 50 40 80 18 86.96 84.99 38.5147 18 50 40 120 24 93.93 96.56 39.8478 table 3 shows the mean of the response of each factor at a certain level and it was represented graphically in fig. 3. at each column of this table, the bold values refer to the maximum calculated mean of response (mn re%). it is obvious from the results of mean response that the most essential factors are in the following order: time ˃ c.d. ˃ mesh number ˃ initial mn concentration. table 3. calculated mean of response for data obtained from mn removal experiments level mn conc. c.d time mesh number 1 81.19 71.57 71.81 78.81 2 80.70 82.87 79.91 79.19 3 88.39 91.11 84.83 delta 0.50 16.83 19.30 6.02 rank 4 2 1 3 fig. 3. main effect plot for means values of re% for mn removal the response table for the calculated signal to noise ratios (lb) and the ranks of the four studied factors are shown in table 4 and which is represented graphically in fig. 4; these ranks are based on delta statistics which compare the relative magnitude of effects. the highest average for each factor minus the lowest average for the same is the delta statistics ‎[38]. lager the s/n ratio means higher the mn re%. so, in this table, the boldfaces refer to the maximum value of the s/n ratios of a certain factor among three levels for (time, c.d., and mesh number) and for two levels of mn conc., it was obvious from the ranks attained for each factor that time is the most influential factor, whereas c.d., mesh size, and mn conc. were the least influential factors for mn respectively. based on the optimization of the multiple regression equation (eq. (12)) and the results of means and s/n ratios, the optimum factors were initial mn conc. (a) of 100 ppm, c.d. (b) of 40ma/cm 2 , time (c) of 120 min, and mesh number (d) of 30 wire/inch. table 4. response table for s/n (larger is better) level mn conc. c.d time mesh number 1 38.09 37.02 37.07 37.80 2 38.06 38.30 37.98 37.94 3 38.90 39.17 38.48 delta 0.03 1.88 2.09 0.69 rank 4 2 1 3 r. h. salman/ iraqi journal of chemical and petroleum engineering20,1 (2019) 39-48 00 fig. 4. main effect plots of s/n (larger is better) for mn re % 3.2. analysis of variance (anova) anova statistical method was implemented to evaluate the significance of the controlling parameters by estimating the percentage contribution of each factor which is the portion of a total observed variance in the experiment for each significant factor. the greater value of contribution percentage for any studied parameter means that it has a high contribution to the final results. also, a superior understanding can be obtained by this analysis and it shows if the detected results are reliable and whether or not the conductance of experiments was at the controlled conditions. anova was established based on the degree of freedom (df), the sum of the square (ss), the percentage contribution of each parameter, the adjusted sum of squares (adj ss), the adjusted mean of the square (adj ms), f-value, and pvalue. all these values are calculated for each controllable factor ‎[29], ‎[39]. the results of anova for the present study are depicted in table 5. it is obvious from the results that the most significant factors that affect mn removal efficiency were as in the following order: time > c.d. > mesh size > mn conc., based on their contribution %. the significance of each factor on the response is also can be determined by p-value, which is defined as a relation between the parameters’ sum of the square to the total sum of square. if the p-value is lower than 0.05 (for a confidence level of 95%), this means that the parameter is significant ‎[40]. it can be concluded from the results of p-values (which based on a confidence level of 95%) for time and c.d. that these parameters were significant, while mesh size had a fair significance and initial mn conc. had no significance in the chosen range in this study. when f > 1 for the controllable parameters, this revealed that the error variance is lower than variances of these factors, and signifying that these controllable factors had major effects on the responses ‎[29]. so, based on the results of the present study all the studied factors were significant except initial mn concentration. table 5. analysis of variance (anova) for mn removal source df seq ss contribution% adj ss adj ms fvalue pvalue mn conc. 1 1.11 0.05 % 1.11 1.110 0.05 0.831 c.d. 2 882.74 37.13 % 882.74 441.371 19.19 0.000 time 2 1127.22 47.42 % 1127.22 563.611 24.51 0.000 mesh number 2 136.23 5.73 % 136.23 68.113 2.96 0.098 error 10 229.95 9.67 % 229.95 22.995 total 17 2377.25 100.00% 3.3. confirmation experiment the confirmation experiment is an important step and is highly endorsed by the taguchi approach to validate the experiment results. in this study, two confirmation experiments were carried out by utilizing the optimum parameters. the results showed that mn re% was 99.34 and 99.45% respectively.\ 3.3. effect of operative factors a. effect of initial mn concentration fig. 5 was plotted by applying eq. (12) at the optimum conditions and it shows the effect of mn initial concentration on the removal efficiency of the ecf process. it is obvious that increasing the initial concentration of mn leads to increase in the predicted removal efficiency and this result is in agreement with previous studies ‎[4]. however, the chosen range of mn initial concentration had not that great influence on the removal efficiency and this was clear from the results of s/n and anova when the fvalue was 0.05 either less than 1 and the contribution percentage was 0.05% which means that it was not a significant factor on the process performance. fig. 5. effect of initial mn concentration on mn re% at c.d. = 40 ma/cm 2 and mesh number = 30 mm r. h. salman/ iraqi journal of chemical and petroleum engineering20,1 (2019) 39-48 04 b. effect of current density it is well known that one of the most effective parameters in the ecf process generally is the current density. the efficiency of this process is affected directly by the value of this parameter. flocs size and growth are affected by current density. increasing current density leads to flocs generation with significant amounts due to more release of ferric ions by anodic dissolution (according to faraday's law ‎[37] ( ⁄ ), and thereby more generation of iron hydroxides essential to coagulants formation. also, the generation rate and distribution of h2 gas bubbles formed at the cathode are affected directly by the value of current density. increasing the current density leads to an increase in bubble generation rate with a decreased in bubble size which leads to high metal removal by h2 flotation ‎[15], ‎[22], ‎[41]–‎[43]. fig. 5 was plotted by applying eq. (12) to examine the effect of increasing the current density on mn re %. current density increased from 20 to 40(ma/cm 2 ) with 100 ppm of mn, 120 min of electrolysis time, and using a screen with mesh number of 30 wire/inch. the removal efficiency increased from 86.734 at 20 ma/cm 2 to > 100% at 40 ma/cm 2 . also, this was obvious from the results of s/n, increasing the current density leads to larger values of s/n which means higher re% of mn removal. fig. 6. effect of c.d. on mn re % at initial mn conc. = 100 ppm and mesh number =30 wire/inch c. effect of electrolysis time according to faraday’s law mentioned previously, the amount of generated ferrous ions which is produced by anode dissolution is related to the electrolysis time of ecf process ‎[13], ‎[15], ‎[44]. in the present, study it was clear from the results of s/n and anova that electrolysis time had the greatest impact on ecf performance. increasing electrolysis time leads to an increase in flocs generation which causing an enhancement in mn removal efficiency. the influence of electrolysis time on mn re % is obvious in fig. 5 and fig. 6 which was plotted by applying eq. (12) at optimum conditions. it is evident that increasing electrolysis time gives an increase in mn removal efficiency due to an increase in the number of generated ferrous hydroxide and an increase in the rate and size of h2 bubble production. for the example at 20 ma/cm 2 the removal efficiency increased from 70.158 to 86.734% by increasing electrolysis time from 40 to 120 min. d. effect of mesh number the mesh number of screens in the present study had the following values 14, 24, and 30 wire/inch and higher porosity and specific surface area had been attained by increasing the mesh number. increasing mesh no. leads to an increase in the number of h2 bubbles which have a small size hence increasing the flotation efficiency and more pollutants can be removed. so, by increasing the mesh number the removal efficiency of mn by ecf process was enhanced. this is obvious from fig. 7 which represents the effect of different mesh number on the removal efficiency at optimum conditions. the results of s/n and anova showed that changing mesh size had a fair significance on mn re %. fig. 7. effect of mesh number on mn re % at initial mn conc. = 100 ppm and c.d. = 40 ma/cm 2 it is worthy to mention that in figures (5-7), some mn re % values exceeded 100 %. this result is attained because these figures were plotted by applying eq.(12), which represents the predicted values not the real one and also minitab software does not have any sense of the figures and it makes the calculations by numerical procedure, this result is in agreement with a previous study ‎[29]. 0 20 40 60 80 100 0 20 40 60 80 100 120 r e % time (min) 20 (ma/cm^2) 30 (ma/cm^2) 40 (ma/cm^2) 0 20 40 60 80 100 0 20 40 60 80 100 120 r e % time (min) 18 wire/inch 24 wire/inch 30 wire/inch r. h. salman/ iraqi journal of chemical and petroleum engineering20,1 (2019) 39-48 04 5conclusions in the present work, the ecf batch process using stainless steel mesh sacrificial electrodes for the treatment of aqueous solution containing mn was studied. the effect of mn initial concentration, current density, electrolysis time, and mesh size of the screen electrodes was examined to detect their impact on the removal efficiency. taguchi method was applied to optimize ecf operating factors. the results of s/n and anova approved that the importance of operating parameters followed the order: time > c.d. > mesh number > initial mn conc., with contribution percentage of 47.42, 37.13, 5.73, and 0.05 % respectively. the optimum conditions were 100 ppm of mn concentration, 40 ma/cm 2 of current density, 120 min of electrolysis time, and 30 wire/inch of mesh number. it can be concluded from the results of the present study that electrolysis time and current density were the most influential parameters and the mesh size that has not been widely investigated in previous studies revealed a fair effect on ecf process, while mn initial concentration had not any mentioned effect on the performance of the removal efficiency. two confirmation tests were conducted at optimum conditions gave mn removal efficiency higher than 99%. consequently, it can be concluded that the ecf process with stainless steel mesh electrodes was very effective in mn removal. nomenclature nomenclature meaning units specified area of a screen cm 2 initial concentration ppm final concentration ppm d wire diameter m faraday’s constant = 96486 c/mol current intensity c/sec l screen thickness cm molecular weight of iron or hydroxide ion g/mol m iron and hydroxide ions amounts g weight of screen g n number of repetitions ratio cm -1 specific surface area cm -1 time sec yi performance results of the ith experiment number of electrons removal percentage ρs density gm/cm 3 porosity references [1] i. d. de mota, j. a. de castro, r. d. casqueira , a. gomes, and a. g. d. junior, “study of electroflotation method for treatment of wastewater from washing soil contaminated by heavy metals” j. mater res technol., vol. 4, no. 2, pp. 109-113, 2015. [2] z. al-qodah and m. al-shannag, “heavy metal ions removal from wastewater using electrocoagulation processes: a comprehensive review,” sep. sci. technol., vol. 6395, no. september, 2017. [3] a. shafaei, m. rezaie, and m. nikazar, “evaluation of mn 2+ and co 2+ removal by electrocoagulation : a case study,” chem. eng. process. process intensif., vol. 50, no. 11–12, pp. 1115–1121, 2011. [4] e. gatsios, j. n. hahladakis, and e. gidarakos, “optimization of electrocoagulation (ec) process for the purification of a real industrial wastewater from toxic metals,” j. environ. manage., vol. 154, pp. 117– 127,2015. [5] p. ganesan, j. lakshmi, g. sozhan, and s. vasudevan, “removal of manganese from water by electrocoagulation: adsorption, kinetics and thermodynamic studies,” the canadian journal of chemical engineering, vol. 9999, pp. 1–11, 2012. [6] l. p. lingamdinne, y. chang, j. yang, j. singh, e. choi, m. shiratani, j. r. koduru, and p. attri, “biogenic reductive preparation of magnetic inverse spinel iron oxide nanoparticles for the adsorption removal of heavy metals,” chem. eng. j., vol. 307, no. january, pp. 74-84, 2016. [7] p. ghosh, a. n. samanta, and s. ray, “reduction of cod and removal of zn 2+ from rayon industry wastewater by combined electro-fenton treatment and chemical precipitation,” desalination, vol. 266, pp. 213–217, 2011. [8] b. alyüz and s. veli, “kinetics and equilibrium studies for the removal of nickel and zinc from aqueous solutions by ion exchange resins,” journal of hazardous materials, vol. 167, pp. 482–488, 2009. [9] a. abdolali, h. h. ngo, w. guo, j. l. zhou, j. zhang, s. liang, s. w. chang, d. d. nguyen, and y. liu, “application of a breakthrough biosorbent for removing heavy metalsfrom synthetic and real wastewaters in a lab − scale continuous a continuous fixed − bed study was carried out utilising a breakthrough biosorbent ,” bioresour. technol., vol. 229, pp. 78-87, 2017. [10] u. divrikli, a. a. kartal, m. soylak, and l. elci, “preconcentration of pb (ii), cr (iii), cu (ii), ni (ii) and cd (ii) ions in environmental samples by membrane filtration prior to their flame atomic absorption spectrometric determinations,” journal of hazardous materials, vol. 145, pp. 459–464, 2007. [11] m. al-abri, a. dakheel, c. tizaoui, and n. hilal, “combined humic substance and heavy metals coagulation , and membrane filtration under saline conditions,” desalination, vol. 253, pp. 46–50, 2010. https://www.sciencedirect.com/science/article/pii/s2238785414001112?via%3dihub https://www.sciencedirect.com/science/article/pii/s2238785414001112?via%3dihub https://www.sciencedirect.com/science/article/pii/s2238785414001112?via%3dihub https://www.sciencedirect.com/science/article/pii/s2238785414001112?via%3dihub https://www.sciencedirect.com/science/article/pii/s2238785414001112?via%3dihub https://www.tandfonline.com/doi/full/10.1080/01496395.2017.1373677 https://www.tandfonline.com/doi/full/10.1080/01496395.2017.1373677 https://www.tandfonline.com/doi/full/10.1080/01496395.2017.1373677 https://www.tandfonline.com/doi/full/10.1080/01496395.2017.1373677 https://www.sciencedirect.com/science/article/abs/pii/s025527011100211x?via%3dihub https://www.sciencedirect.com/science/article/abs/pii/s025527011100211x?via%3dihub https://www.sciencedirect.com/science/article/abs/pii/s025527011100211x?via%3dihub https://www.sciencedirect.com/science/article/abs/pii/s025527011100211x?via%3dihub https://www.sciencedirect.com/science/article/pii/s0301479715000869?via%3dihub https://www.sciencedirect.com/science/article/pii/s0301479715000869?via%3dihub https://www.sciencedirect.com/science/article/pii/s0301479715000869?via%3dihub https://www.sciencedirect.com/science/article/pii/s0301479715000869?via%3dihub https://www.sciencedirect.com/science/article/pii/s0301479715000869?via%3dihub https://onlinelibrary.wiley.com/doi/abs/10.1002/cjce.21709 https://onlinelibrary.wiley.com/doi/abs/10.1002/cjce.21709 https://onlinelibrary.wiley.com/doi/abs/10.1002/cjce.21709 https://onlinelibrary.wiley.com/doi/abs/10.1002/cjce.21709 https://onlinelibrary.wiley.com/doi/abs/10.1002/cjce.21709 https://www.sciencedirect.com/science/article/pii/s138589471631141x?via%3dihub https://www.sciencedirect.com/science/article/pii/s138589471631141x?via%3dihub https://www.sciencedirect.com/science/article/pii/s138589471631141x?via%3dihub https://www.sciencedirect.com/science/article/pii/s138589471631141x?via%3dihub https://www.sciencedirect.com/science/article/pii/s138589471631141x?via%3dihub https://www.sciencedirect.com/science/article/pii/s138589471631141x?via%3dihub https://www.sciencedirect.com/science/article/pii/s0011916410006089?via%3dihub https://www.sciencedirect.com/science/article/pii/s0011916410006089?via%3dihub https://www.sciencedirect.com/science/article/pii/s0011916410006089?via%3dihub https://www.sciencedirect.com/science/article/pii/s0011916410006089?via%3dihub https://www.sciencedirect.com/science/article/pii/s0011916410006089?via%3dihub https://www.sciencedirect.com/science/article/pii/s0304389409000296?via%3dihub https://www.sciencedirect.com/science/article/pii/s0304389409000296?via%3dihub https://www.sciencedirect.com/science/article/pii/s0304389409000296?via%3dihub https://www.sciencedirect.com/science/article/pii/s0304389409000296?via%3dihub https://www.sciencedirect.com/science/article/pii/s0960852417300366?via%3dihub https://www.sciencedirect.com/science/article/pii/s0960852417300366?via%3dihub https://www.sciencedirect.com/science/article/pii/s0960852417300366?via%3dihub https://www.sciencedirect.com/science/article/pii/s0960852417300366?via%3dihub https://www.sciencedirect.com/science/article/pii/s0960852417300366?via%3dihub https://www.sciencedirect.com/science/article/pii/s0960852417300366?via%3dihub https://www.sciencedirect.com/science/article/pii/s0960852417300366?via%3dihub https://www.sciencedirect.com/science/article/pii/s0960852417300366?via%3dihub https://www.sciencedirect.com/science/article/pii/s030438940601404x?via%3dihub https://www.sciencedirect.com/science/article/pii/s030438940601404x?via%3dihub https://www.sciencedirect.com/science/article/pii/s030438940601404x?via%3dihub https://www.sciencedirect.com/science/article/pii/s030438940601404x?via%3dihub https://www.sciencedirect.com/science/article/pii/s030438940601404x?via%3dihub https://www.sciencedirect.com/science/article/pii/s030438940601404x?via%3dihub https://www.sciencedirect.com/science/article/pii/s0011916409013253?via%3dihub https://www.sciencedirect.com/science/article/pii/s0011916409013253?via%3dihub https://www.sciencedirect.com/science/article/pii/s0011916409013253?via%3dihub https://www.sciencedirect.com/science/article/pii/s0011916409013253?via%3dihub r. h. salman/ iraqi journal of chemical and petroleum engineering20,1 (2019) 39-48 04 [12] h. polat and d. erdogan, “heavy metal removal from waste waters by ion flotation,” journal of hazardous materials, vol. 148, pp. 267–273, 2007. [13] b. al aji, y. yavuz, and a. s. koparal, “electrocoagulation of heavy metals containing model wastewater using monopolar iron electrodes,” separation and purification technology, vol. 86, pp. 248–254, 2012. [14] u. t. un and s. e. ocal, “removal of heavy metals ( cd , cu , ni ) by electrocoagulation,” international journal of environmental science and development, vol. 6, no. 6, 2015. [15] e. bazrafshan, l. mohammadi, a. ansarimoghaddam, and a. h. mahvi, “heavy metals removal from aqueous environments by electrocoagulation process – a systematic review,” j. environ. heal. sci. eng., vol. 13:74, pp. 1–16, 2015. [16] d. bhagawan, s. poodari, t. pothuraju, d. srinivasulu, g. shankaraiah, m. y. rani, v. himabindu, and s. vidyavath, “effect of operational parameters on heavy metal removal by electrocoagulation,” environ sci pollut res, vol. 21, no. 24, pp 14166–14173, 2014. [17] t. m. rekha, b. vinod, and k. v. r. murthy “removal of heavy metals from electroplating industry by electrocoagulation ,” journal of chemical and pharmaceutical sciences, no. 3, pp. 111–118, 2014. [18] r. g. casqueira, m. l. torem, and h. m. kohler, “the removal of zinc from liquid streams by electroflotation,” minerals engineering, vol. 19, pp. 1388–1392, 2006. [19] ö. hanay and h. hasar, “effect of anions on removing cu 2+ , mn 2+ and zn 2+ in electrocoagulation process using aluminum electrodes,” journal of hazardous materials, vol. 189, pp. 572–576, 2011. [20] a. h. abbar, r. h. salman, and a. s. abbas, “cadmium removal using a spiral-wound woven wire meshes packed bed rotating cylinder electrode,” environ. technol. innov., vol. 13, pp. 233–243, 2019. [21] m. al-shannag, z. al-qodah, k. bani-melhem, and m. r. qtaishat, and m. alkasrawi, “heavy metal ions removal from metal plating wastewater using electrocoagulation : kinetic study and process performance,” chem. eng. j., vol. 260, pp. 749–756, 2015. [22] m. prica, s. adamovic, b. dalmacija, l. rajic, j. trickovic, s. rapajic, and m. becelic-tomin “the electrocoagulation / flotation study : the removal of heavy metals from the waste fountain solution,” process saf. environ. prot., vol. 94, no. march, pp. 262–273, 2014. [23] k. choo, s. han, s. choi, j. jung, d. chang, j. ahn, and m. m. benjamin, “use of chelating polymers to enhance manganese removal in ultrafiltration for drinking water treatment,” j. ind. eng. chem., vol. 13, no. 2, pp. 163–169, 2007. [24] b. guan, w. ni, z. wu, and y. lai, “removal of mn (ii) and zn (ii) ions from flue gas desulfurization wastewater with water-soluble chitosan,” separation and purification technology, vol. 65, pp. 269–274, 2009. [25] p. taylor and d. maria, “manganese removal from groundwater : characterization of filter media coating,” desalination and water treatment, pp.1-13, 2014. [26] i. j. idan, l. c. abdullah, and t. s. choong, “equilibrium, kinetics and thermodynamic adsorption studies of acid dyes on adsorbent developed from kenaf core fiber,” adsorption science & technology, pp. 1-19, 2017. [27] a. h. abbar, r. h. salman, and a. s. abbas, “studies of mass transfer at a spiral-wound woven wire mesh rotating cylinder electrode,” chem. eng. process: process intensif., vol. 127, no. january, pp. 10–16, 2018. [28] g. kiani, m. soltanzadeh, and i. ahadzadeh, “adsorption study of zinc ion onto halloysite nanotubes using taguchi’s design of experimental methodology,” int. j. nano dimens., vol. 9, no. 3, pp. 246–259, 2018. [29] f. googerdchian, a. moheb, r. emadi, and m. asgari, “optimization of pb (ii) ions adsorption on nanohydroxyapatite adsorbents by applying taguchi method,” j. hazard. mater., vol. 349, no. august 2017, pp. 186–194, 2018. [30] c. wang, h. liu, z. liu, y. gao, b. wu, and h. xu, “fe3o4 nanoparticle-coated mushroom source biomaterial for cr(vi) polluted liquid treatment and mechanism research,” r. soc. open sci, 5: 171776, 2018. [31] h. y. yen, and c. p. lin, “adsorption of cd (ii) from wastewater using spent coffee grounds by taguchi optimization,” desalination and water treatment, no. july, pp.1-8, 2015. [32] a. s. abbas, m. h. hafiz, and r. h. salman, “indirect electrochemical oxidation of phenol using rotating cylinder reactor,” iraqi journal of chemical and petroleum engineering, vol. 176, no. 4, 2016. [33] r. pundir, g. h. v. c. chary, and m. g. dastidar, “application of taguchi method for optimizing the process parameters for the removal of copper and nickel by growing aspergillus sp .,” water resour. ind., vol. 20, pp. 83-92, 2016. [34] g. zolfaghari, a. esmaili-sari, m. anbia, and h. younesi, “taguchi optimization approach for pb (ii) and hg (ii) removal from aqueous solutions using modified mesoporous carbon,” j. hazard. mater., vol. 192, no. 3, pp. 1046–1055, 2011. [35] b. razmi and r. ghasemi-fasaei, “investigation of taguchi optimization, equilibrium isotherms, and kinetic modeling for phosphorus adsorption onto natural zeolite of clinoptilolite type,” adsorption science & technology, pp. 1-14, 2018. https://www.sciencedirect.com/science/article/pii/s0304389407002634?via%3dihub https://www.sciencedirect.com/science/article/pii/s0304389407002634?via%3dihub https://www.sciencedirect.com/science/article/pii/s0304389407002634?via%3dihub https://www.sciencedirect.com/science/article/pii/s1383586611006551?via%3dihub https://www.sciencedirect.com/science/article/pii/s1383586611006551?via%3dihub https://www.sciencedirect.com/science/article/pii/s1383586611006551?via%3dihub https://www.sciencedirect.com/science/article/pii/s1383586611006551?via%3dihub https://www.sciencedirect.com/science/article/pii/s1383586611006551?via%3dihub https://www.researchgate.net/profile/eren_oecal/publication/269404945_removal_of_heavy_metals_cd_cu_ni_by_electrocoagulation/links/548a97350cf2d1800d7aaee0/removal-of-heavy-metals-cd-cu-ni-by-electrocoagulation.pdf https://www.researchgate.net/profile/eren_oecal/publication/269404945_removal_of_heavy_metals_cd_cu_ni_by_electrocoagulation/links/548a97350cf2d1800d7aaee0/removal-of-heavy-metals-cd-cu-ni-by-electrocoagulation.pdf https://www.researchgate.net/profile/eren_oecal/publication/269404945_removal_of_heavy_metals_cd_cu_ni_by_electrocoagulation/links/548a97350cf2d1800d7aaee0/removal-of-heavy-metals-cd-cu-ni-by-electrocoagulation.pdf https://www.researchgate.net/profile/eren_oecal/publication/269404945_removal_of_heavy_metals_cd_cu_ni_by_electrocoagulation/links/548a97350cf2d1800d7aaee0/removal-of-heavy-metals-cd-cu-ni-by-electrocoagulation.pdf https://jehse.biomedcentral.com/articles/10.1186/s40201-015-0233-8 https://jehse.biomedcentral.com/articles/10.1186/s40201-015-0233-8 https://jehse.biomedcentral.com/articles/10.1186/s40201-015-0233-8 https://jehse.biomedcentral.com/articles/10.1186/s40201-015-0233-8 https://jehse.biomedcentral.com/articles/10.1186/s40201-015-0233-8 https://link.springer.com/article/10.1007/s11356-014-3331-8 https://link.springer.com/article/10.1007/s11356-014-3331-8 https://link.springer.com/article/10.1007/s11356-014-3331-8 https://link.springer.com/article/10.1007/s11356-014-3331-8 https://link.springer.com/article/10.1007/s11356-014-3331-8 https://link.springer.com/article/10.1007/s11356-014-3331-8 https://www.jchps.com/specialissues/special%20issue3/23%20jchps%20si3%20t.malathi%20rekha%20111-118.pdf https://www.jchps.com/specialissues/special%20issue3/23%20jchps%20si3%20t.malathi%20rekha%20111-118.pdf https://www.jchps.com/specialissues/special%20issue3/23%20jchps%20si3%20t.malathi%20rekha%20111-118.pdf https://www.jchps.com/specialissues/special%20issue3/23%20jchps%20si3%20t.malathi%20rekha%20111-118.pdf https://www.jchps.com/specialissues/special%20issue3/23%20jchps%20si3%20t.malathi%20rekha%20111-118.pdf https://www.sciencedirect.com/science/article/abs/pii/s0892687506000574?via%3dihub https://www.sciencedirect.com/science/article/abs/pii/s0892687506000574?via%3dihub https://www.sciencedirect.com/science/article/abs/pii/s0892687506000574?via%3dihub https://www.sciencedirect.com/science/article/abs/pii/s0892687506000574?via%3dihub https://www.sciencedirect.com/science/article/pii/s0304389411002743 https://www.sciencedirect.com/science/article/pii/s0304389411002743 https://www.sciencedirect.com/science/article/pii/s0304389411002743 https://www.sciencedirect.com/science/article/pii/s0304389411002743 https://www.sciencedirect.com/science/article/pii/s2352186418303912?via%3dihub https://www.sciencedirect.com/science/article/pii/s2352186418303912?via%3dihub https://www.sciencedirect.com/science/article/pii/s2352186418303912?via%3dihub https://www.sciencedirect.com/science/article/pii/s2352186418303912?via%3dihub https://www.sciencedirect.com/science/article/pii/s1385894714012212?via%3dihub https://www.sciencedirect.com/science/article/pii/s1385894714012212?via%3dihub https://www.sciencedirect.com/science/article/pii/s1385894714012212?via%3dihub https://www.sciencedirect.com/science/article/pii/s1385894714012212?via%3dihub https://www.sciencedirect.com/science/article/pii/s1385894714012212?via%3dihub https://www.sciencedirect.com/science/article/pii/s1385894714012212?via%3dihub https://www.sciencedirect.com/science/article/pii/s0957582014000974?via%3dihub https://www.sciencedirect.com/science/article/pii/s0957582014000974?via%3dihub https://www.sciencedirect.com/science/article/pii/s0957582014000974?via%3dihub https://www.sciencedirect.com/science/article/pii/s0957582014000974?via%3dihub https://www.sciencedirect.com/science/article/pii/s0957582014000974?via%3dihub https://www.sciencedirect.com/science/article/pii/s0957582014000974?via%3dihub https://www.cheric.org/pdf/jiec/ie13/ie13-2-0163.pdf https://www.cheric.org/pdf/jiec/ie13/ie13-2-0163.pdf https://www.cheric.org/pdf/jiec/ie13/ie13-2-0163.pdf https://www.cheric.org/pdf/jiec/ie13/ie13-2-0163.pdf https://www.cheric.org/pdf/jiec/ie13/ie13-2-0163.pdf https://www.sciencedirect.com/science/article/pii/s138358660800436x?via%3dihub https://www.sciencedirect.com/science/article/pii/s138358660800436x?via%3dihub https://www.sciencedirect.com/science/article/pii/s138358660800436x?via%3dihub https://www.sciencedirect.com/science/article/pii/s138358660800436x?via%3dihub https://www.sciencedirect.com/science/article/pii/s138358660800436x?via%3dihub https://www.tandfonline.com/doi/full/10.1080/19443994.2014.927802 https://www.tandfonline.com/doi/full/10.1080/19443994.2014.927802 https://www.tandfonline.com/doi/full/10.1080/19443994.2014.927802 https://www.tandfonline.com/doi/full/10.1080/19443994.2014.927802 https://journals.sagepub.com/doi/10.1177/0263617417715532 https://journals.sagepub.com/doi/10.1177/0263617417715532 https://journals.sagepub.com/doi/10.1177/0263617417715532 https://journals.sagepub.com/doi/10.1177/0263617417715532 https://journals.sagepub.com/doi/10.1177/0263617417715532 https://www.sciencedirect.com/science/article/abs/pii/s0255270118300369?via%3dihub https://www.sciencedirect.com/science/article/abs/pii/s0255270118300369?via%3dihub https://www.sciencedirect.com/science/article/abs/pii/s0255270118300369?via%3dihub https://www.sciencedirect.com/science/article/abs/pii/s0255270118300369?via%3dihub https://www.sciencedirect.com/science/article/abs/pii/s0255270118300369?via%3dihub http://www.ijnd.ir/article_30891.html http://www.ijnd.ir/article_30891.html http://www.ijnd.ir/article_30891.html http://www.ijnd.ir/article_30891.html http://www.ijnd.ir/article_30891.html https://www.sciencedirect.com/science/article/pii/s0304389418300712?via%3dihub https://www.sciencedirect.com/science/article/pii/s0304389418300712?via%3dihub https://www.sciencedirect.com/science/article/pii/s0304389418300712?via%3dihub https://www.sciencedirect.com/science/article/pii/s0304389418300712?via%3dihub https://www.sciencedirect.com/science/article/pii/s0304389418300712?via%3dihub https://royalsocietypublishing.org/doi/10.1098/rsos.171776 https://royalsocietypublishing.org/doi/10.1098/rsos.171776 https://royalsocietypublishing.org/doi/10.1098/rsos.171776 https://royalsocietypublishing.org/doi/10.1098/rsos.171776 https://royalsocietypublishing.org/doi/10.1098/rsos.171776 https://www.tandfonline.com/doi/full/10.1080/19443994.2015.1042063 https://www.tandfonline.com/doi/full/10.1080/19443994.2015.1042063 https://www.tandfonline.com/doi/full/10.1080/19443994.2015.1042063 https://www.tandfonline.com/doi/full/10.1080/19443994.2015.1042063 https://www.tandfonline.com/doi/abs/10.1080/19443994.2014.963687 https://www.tandfonline.com/doi/abs/10.1080/19443994.2014.963687 https://www.tandfonline.com/doi/abs/10.1080/19443994.2014.963687 https://www.tandfonline.com/doi/abs/10.1080/19443994.2014.963687 https://www.tandfonline.com/doi/abs/10.1080/19443994.2014.963687 https://www.sciencedirect.com/science/article/pii/s2212371716300403?via%3dihub https://www.sciencedirect.com/science/article/pii/s2212371716300403?via%3dihub https://www.sciencedirect.com/science/article/pii/s2212371716300403?via%3dihub https://www.sciencedirect.com/science/article/pii/s2212371716300403?via%3dihub https://www.sciencedirect.com/science/article/pii/s2212371716300403?via%3dihub https://www.sciencedirect.com/science/article/pii/s0304389411007680 https://www.sciencedirect.com/science/article/pii/s0304389411007680 https://www.sciencedirect.com/science/article/pii/s0304389411007680 https://www.sciencedirect.com/science/article/pii/s0304389411007680 https://www.sciencedirect.com/science/article/pii/s0304389411007680 https://journals.sagepub.com/doi/10.1177/0263617418779738 https://journals.sagepub.com/doi/10.1177/0263617418779738 https://journals.sagepub.com/doi/10.1177/0263617418779738 https://journals.sagepub.com/doi/10.1177/0263617418779738 https://journals.sagepub.com/doi/10.1177/0263617418779738 r. h. salman/ iraqi journal of chemical and petroleum engineering20,1 (2019) 39-48 04 [36] s. s. madan and k. l. wasewar, “optimization for benzeneacetic acid removal from aqueous solution using cao2 nanoparticles based on taguchi method,” j. appl. res. technol., vol. 15, no. 4, pp. 332–339, 2017. [37] ö. gökkuş, and y. ş. yıldız, “application of electrocoagulation for treatment of medical waste sterilization plant wastewater and optimization of the experimental conditions,” clean technol. environ. policy, vol. 17, pp. 1717–1725, 2015. [38] h. ashassi-sorkhabi and r. bagheri, “sonoelectrochemical synthesis, optimized by taguchi method, and corrosion behavior of polypyrrole-silicon nitride nanocomposite on st-12 steel,” synth. met., vol. 195, pp. 1–8, 2014. [39] a. zirehpour, a. rahimpour, m. jahanshahi, and m. peyravi, “mixed matrix membrane application for olive oil wastewater treatment: process optimization based on taguchi design method,” j. environ. manage., vol. 132, pp. 113–120, 2014. [40] g. barman, a. kumar, and p. khare, “removal of congo red by carbonized low-cost adsorbents: process parameter optimization using a taguchi experimental design,” j. chem. eng. data, vol. 56, no. 11, pp. 4102–4108, 2011. [41] a. shafaei, m. rezayee, m. arami, and m. nikazar, “removal of mn 2+ ions from synthetic wastewater by electrocoagulation process,” desalination, vol. 260, pp. 23–28, 2010. [42] f. akbal, and s. camci, “comparison of electrocoagulation and chemical coagulation for heavy metal removal,” chem. eng. technol., vol. 33, no. 10, pp. 1655–1664, 2010. [43] b. merzouk, b. gourich, a. sekki, k. madani, and m. chibane, “removal turbidity and separation of heavy metals using electrocoagulation– electroflotation technique a case study,” j. hazard. mater.,vol. 164, pp. 215–222, 2009. [44] g. ghanizadeh, g. s. neghab, m. salem, and k. khalagi , “taguchi experimental design for electrocoagulation process using alternating and direct current on fluoride removal from water,” desalination and water treat., no. may, pp. 1–9, 2015. ( من مياه الصرف المصنعة بواسطة تقنيات التخثر/ التعويم +mn2إزالة أيونات المنغنيز ) الكهربائية باستخدام أقطاب الفوالذ المشبكية: أيجاد الظروف المثمى بواسطة طريقة تاكوشي الخالصة / انصشف انصحٓ ثُاسطخ رقىٕبد انزخثشفٓ ٌزي انذساسخ ، رم انزحقق فٓ كفبءح إصانخ أُٔوبد انمىغىٕض مه مٕبي ( ، صمه انزحهٕم انكٍشثبئٓ ، .c.dانزعُٔم انكٍشثبئٕخ. رمذ دساسخ رأثٕش رشكٕض انمىغىٕض األثزذائٓ ، كثبفخ انزٕبس ) ٕخ مه خالل رطجٕق رصمٕم ربكُشٓ الٔجبد انظشَف انمثهّ َحجم انمشجك ألقطبة انفُالر انمشجكٕخ فٓ خهٕخ دفع ٌُ ( أن انظشَف انمثهّ كبوذ, انزشكٕضاألثزذائٓ نهمىغىٕضs/nألقصّ كفبءح إصانخ نهمىغىٕض. أظٍشد وزبئج ) َأش/أوج. 30دقٕقخ ، َشجكخ راد حجم 120، ََقذ 2مههٓ أمجٕش / سم c.d. ٌُ4 جضء فٓ انمهُٕن ، 100 ( انزْ ٔشٕش إنّ أن انىسجخ anovaرم ثحث األٌمٕخ انىسجٕخ نكم عبمم عه طشٔق رحهٕم انزجبٔه ) أٔضب ، ( ، َ 5.43%( ، حجم انمشجك )34.13 %) .c.d( ، 44.42%انمئُٔخ نهمسبٌمخ رزجع انزشرٕت: انُقذ ) ُامم األكثش رأثٕشاً َحجم كبوذ ٌٓ انع .c.d(. َقذ انزحهٕم انكٍشثبئٓ َ 0.05%انزشكٕضاألثزذائٓ نهمىغىٕض ٌُ ) انشجكخ نً رأثٕش مقجُل عهّ كفبءح إصانخ أُٔوبد انمىغىٕض ، فٓ حٕه أن انزشكٕضاألثزذائٓ نهمىغىٕض نم ٔكه نً رأثٕش rمزكُس فٓ انمذِ انمذسَط. أظٍش رحهٕم االوحذاس ) 2 ( ارفبقب جٕذا ثٕه انقٕم انزجشٔجٕخ َانقٕم 90.16 = % .99%رأكٕذ أن كفبءح إصانخ انمىغىٕض فٓ انظشَف انمثهّ كبوذ أعهّ مه انمزُقعخ ، َأظٍشد انىزبئج ٓانكهمبد انذانخ: أصانخ انمىغىٕض, انزخثشانكٍشثبئٓ, انزعُٔم انكٍشثبئٓ, أقطبة انفُالر, األقطبة انمشجكٕخ, مٕبي انصشف , طشٔقخ ربكُش https://www.sciencedirect.com/science/article/pii/s1665642317300585?via%3dihub https://www.sciencedirect.com/science/article/pii/s1665642317300585?via%3dihub https://www.sciencedirect.com/science/article/pii/s1665642317300585?via%3dihub https://www.sciencedirect.com/science/article/pii/s1665642317300585?via%3dihub https://www.sciencedirect.com/science/article/pii/s1665642317300585?via%3dihub https://link.springer.com/article/10.1007/s10098-014-0897-2 https://link.springer.com/article/10.1007/s10098-014-0897-2 https://link.springer.com/article/10.1007/s10098-014-0897-2 https://link.springer.com/article/10.1007/s10098-014-0897-2 https://link.springer.com/article/10.1007/s10098-014-0897-2 https://www.sciencedirect.com/science/article/abs/pii/s0379677914001829?via%3dihub https://www.sciencedirect.com/science/article/abs/pii/s0379677914001829?via%3dihub https://www.sciencedirect.com/science/article/abs/pii/s0379677914001829?via%3dihub https://www.sciencedirect.com/science/article/abs/pii/s0379677914001829?via%3dihub https://www.sciencedirect.com/science/article/abs/pii/s0379677914001829?via%3dihub https://www.sciencedirect.com/science/article/pii/s0301479713006816?via%3dihub https://www.sciencedirect.com/science/article/pii/s0301479713006816?via%3dihub https://www.sciencedirect.com/science/article/pii/s0301479713006816?via%3dihub https://www.sciencedirect.com/science/article/pii/s0301479713006816?via%3dihub https://www.sciencedirect.com/science/article/pii/s0301479713006816?via%3dihub https://pubs.acs.org/doi/abs/10.1021/je200554z https://pubs.acs.org/doi/abs/10.1021/je200554z https://pubs.acs.org/doi/abs/10.1021/je200554z https://pubs.acs.org/doi/abs/10.1021/je200554z https://pubs.acs.org/doi/abs/10.1021/je200554z https://www.sciencedirect.com/science/article/pii/s0011916410003048?via%3dihub https://www.sciencedirect.com/science/article/pii/s0011916410003048?via%3dihub https://www.sciencedirect.com/science/article/pii/s0011916410003048?via%3dihub https://www.sciencedirect.com/science/article/pii/s0011916410003048?via%3dihub https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.201000091 https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.201000091 https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.201000091 https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.201000091 https://www.sciencedirect.com/science/article/pii/s0304389408011916 https://www.sciencedirect.com/science/article/pii/s0304389408011916 https://www.sciencedirect.com/science/article/pii/s0304389408011916 https://www.sciencedirect.com/science/article/pii/s0304389408011916 https://www.sciencedirect.com/science/article/pii/s0304389408011916 https://www.tandfonline.com/doi/full/10.1080/19443994.2015.1049562 https://www.tandfonline.com/doi/full/10.1080/19443994.2015.1049562 https://www.tandfonline.com/doi/full/10.1080/19443994.2015.1049562 https://www.tandfonline.com/doi/full/10.1080/19443994.2015.1049562 https://www.tandfonline.com/doi/full/10.1080/19443994.2015.1049562 g.a. rassoul and d.r. rzaige ijcpe vol.9 no.3 (2008) iraqi journal of chemical and petroleum engineering vol.9 no.3 (december 2007) 37-41 issn: 1997-4884 optimization of biochemical treatment of tannery wastewater neran k. ibrahim , ali h. alwan * and mahmood m. barbooti * * * department of chemical engineering, university of technology, baghdad, iraq. ** environmental analysis department, ministry of environment, baghdad, iraq abstract the present work is concerned with the finding of the optimum conditions for biochemical wastewater treatment for a local tannery. the water samples were taken from outline areas (the wastewater of the chrome and vegetable tannery) in equal volumes and subjected to sedimentation, biological treatment, and chemical and natural sedimentation treatment. the box-wilson method of experimental design was adopted to find useful relationships between three operating variables that affect the treatment processes (temperature, aeration period and phosphate concentration) on the biochemical oxygen demand (bod5). the experimental data collected by this method were successfully fitted to a second order polynomial mathematical model. the most favorable operating conditions for the treatment are; temperature 32.5oc, aeration period 10 hours and phosphate concentration 16.8 mg/l. on using the optimum conditions a mathematical model simulating the operation for the treatment was obtained. introduction in leather industry (tanning) and for practical reasons, almost all tanneries are located on rivers to provide them with process water (30 to 80 m3 for 1 ton of processed raw skins) [1] and for the disposal of their effluents. the effluent from this industry is mainly waterborne [2]. the components of the effluent arise from purification of raw hides and skins before processing as well as from residual chemicals from the production processes. hence, the tanning industry had been recognized as a major contributor to water pollution problems. biodegradable organic matter consumes oxygen and nutrients in complex biochemical reactions until rendered inert [3]. this exerts a biochemical oxygen demand as one of the fundamental parameters used to regulate the quality of the effluent [4]. the contaminants in industrial wastewater are removed by physical, chemical and biological means [5]. facilities for handling wastewater are usually considered to have three major parts: collection, treatment and disposal [6]. pre-aeration is used to “freshen” the wastewater and to assist the removal of oil and grease [7]. secondary treatment processes commonly consist of biological processes. this means that living organisms which control the environment of the process are used to partially stabilize (oxidize) organic matter not previously removed by treatment processes and to convert it into a form which is easier to remove from the wastewater [8]. sedimentation or primary treatment makes the wastewater much clearer. two clarifiers are used9 to provide detention time (3 h) where, almost 60% of the suspended solids (ss) will either settle to the bottom or float to the surface and be removed. removal of university of baghdad college of engineering iraqi journal of chemical and petroleum engineering effect of temperature on corrosion of carbon steel boiler tubes in dilute soduim chloride solution 2 ijcpe vol.9 no.3 (2008) these solids will usually reduce the bod5 of the waste approximately 35%. the next step is the biological treatment which can typically be divided into aerobic and anaerobic. anaerobic biological treatment is an oxygen-devoid process. aerobic biological treatment is done in the presence of oxygen. it is applicable to wastewater containing bio-degradable organic constituents and some non-metallic inorganic constituents [2]. the activated sludge process (asp) is the currently used biological treatment process for wastewater in al-za’afaraniya tanning factory, southern baghdad. the system consists of an equalization basin, a settling tank, an aeration basin, a clarifier, and a sludge line. the recirculation of the biomass, which is an integral part of the process, allow microorganisms to adapt changes in wastewater composition with relatively short acclimation time and also allow a greater degree of control over acclaimed bacterial population [10]. for a proper control of the asp, the growth of the microorganisms should be controlled. bacteria make up about 95% of the activated sludge biomass. these single celled organisms grow in the wastewater by consuming (eating) biodegradable materials such as proteins, carbohydrates, fats and many other compounds. some important factors acting on growth and activity of bacteria in biochemical wastewater treatment are: food-to-microorganism ratio (f/m); use of oxygen [11]; formation of floc [12]; mixing [12]; ; ph [13]; temperature [6] and the effect of nutrients [14]. biological oxygen demand (bod) is a measure of the oxygen used by microorganisms to decompose this waste. a large quantity of organic waste in the water requires large amount of bacteria to decompose it. thus, the demand for oxygen will be high (high level of bod). as the waste is consumed or dispersed through the water, bod levels will begin to decline [15]. nitrates and phosphates in a body of water can contribute to high bod levels. nitrates and phosphates are plant nutrients and can cause plant life and algae to grow quickly. when plants grow quickly, they also die quickly. this contributes to the organic waste in the water, which is then decomposed by bacteria. this results in a high bod level [15]. when bod levels are high, dissolved oxygen (do) levels decrease because the oxygen that is available in the water is being consumed by the bacteria. since less dissolved oxygen is available in the water, fish and other aquatic organisms may not survive [16]. the present work is an attempt to shed more light on the pollution potential of “al-za’afaraniya” tanning factory. the bod5 is taken as a parameter to indicate the optimum condition of biological treatment in asp. experimental procedure materials phosphoric acid (70 wt%) was supplied by a local company. the chemicals used for the determination of bod5 and phosphate were of analytical grade. an agar was used to grow bacteria, and consists of: beef extract 3 g; peptone, 5 g; agar, 15 g and distilled water to make a volume of one liter. the culture media is ph = 7.0. malt extract agar was used to grow fungi. it consists of: malt extract, 20 g ; peptone, 5 g, agar, 15 g and distilled water to make a volume of one liter. culture media: ph = 3.5-4.0 laboratory treatment units fig. 1 shows a schematic diagram of the experimental unit used for the biochemical wastewater treatment. the unit consists of: a temperature regulated water bath of (60 x 40 x 16cm) and 1.2 kw power was equipped with a stainless steel electrical stirrer (1.2 kw) and coupled with voltage regulator. the clarifier was a 3liter pyrex flask with a discharge valve at the bottom and a tap near the top, for the collection of treated wastewater. air was introduced via a pre-calibrated rotameter with and an air sparger to ensure even distribution. a pyrex burette was used for the delivery of nutrient (phosphoric acid). some supplementary equipments were used including an incubator (memmert, germany); a microscope (olympus); an autoclave for sterilization (express, england); a digital grating spectrophotometer (pye unicam, england); and a universal pocket meter multiline p4 including: i. ph combined electrode with integrated temperature probe sen tix 41; and ii, dissolved oxygen (do) probe, cell ox 325. procedure the samples were taken from outline area from the wastewater of the vegetable and chrome tannery, in equal volumes. the samples were first screened to remove hair and skins pieces and then neutralized by adding sulfuric acid (50 wt%) to a final ph of (7-9). sedimentation (settling) process was then carried out to reduce the solid content to about 65% within 2-3 h. a specified volume of the sample (30 lit) was placed in the bath. the microorganism (activated sludge) where added to the water sample in the bath, and aeration was started. following the box-wilson method of experimental design the operating parameters used, were in the range; t=20 45o c t=5-10 hour po4 concentration=5-20 mg/l. g.a. rassoul and d.r. rzaige ijcpe vol.9 no.3 (2008) after the biochemical treatment, a polyelectrolyte at a rate of 15 mg/l was added to the mixture in the bath for a period of one hour to improve the sedimentation process of. in the natural sedimentation stage, the sample was taken from the bath and clarified for about 3 h, and then a specified volume (1.0 l) of the clarified water was taken for the bod5 measurement. fig. 1: the experimental apparatus: 1, water bath; 2, burette, 3, compressor; 4, pipes; 5, rotameter; 6, air sparger; 7, voltage variae box; 8, stirrer; 9, clarifier methods of examination: the tss and volatile suspended solids (vss) tests were done according to the who methods for pollution control, 1982. the (do) concentration was measured using a (cell dx 325) type device, which consists of a gold-metal electrode (wissen schuftliche tech. werk., germany). the accuracy of this method is (0.1 mg/lit). the readings were checked versus titration method with standard 0.025 n sodium thiosulfate using starch as an indicator. the dilution, the bod5 measurement and the determination of the phosphate concentration were carried out in accordance with standard methods [17]. the preparation of agar plate and the isolation of discrete colonies from a mixed culture were carried out according to the published methods [18]. results and discussion this work deals with effect of three variables (temperature, aeration period and phosphate concentration) on bod5. postulating the mathematical model a second order polynomial equation was employed in the range of the independent variables. three variables were considered. the general form of a second polynomial equation can be given as follows: y = b10 + b11x11 + b12x12 + b13x13 + b14x12 x13 + b15x2 12 + b16x213 + b17x11x12 + b18x11x13 + b19x12x13 (1) the coded and real variables as well as the real values of bod5 are given in table 1. the data of table 1 were fitted to equation (1) so that the regression analysis of central composite design to the approximating model to obtain the optimum conditions of the process. the coefficients of polynomial equation were evaluated. thus, the best form of equation 1 is: y = 288.498 + 34.846 x11 + 18.289 x12 + 9.892 x13 + 36.896 x211 + 9.151x212 + 7.317x213 + 5x11x12 + 3.75x11x13 + 3.749x12x13 (2) correlation coefficient ® = 0.977, percentage square error (s) = 1.8%. to test the significance of each term in equation (2), the f-distribution test was used employing the variance of each term in multivariable correlation, according to table 1 [19]. the calculations indicated insignificant interaction effect of temperature on corrosion of carbon steel boiler tubes in dilute soduim chloride solution 4 ijcpe vol.9 no.3 (2008) between the variables (x1x3, x1x2, x2x3) are. thus the best form of the relationship is y = 288.498 + 34.846x11 + 18.289x12 + 9.892x13 + 36.896x211 + 9.151x212 + 7.317x213 (3) the optimization process [20] was applied to equation (2) to find the optimum operating conditions and the results indicate the following conditions to attain the minimum bod5 value (256 mg/l): x11 = temperature = 32.5o c, x12 = aeration period = 10 h, x13 = phosphate concentration = 16.8 mg/l. effect of different operation variables on the values of bod5: effect of temperature: fig. 2 shows the influence of temperature on bod5 at different aeration periods at fixed phosphate concentration (16.8 mg/l). it is clear that, the bod5 decreases with increasing temperature down to a value of 250 mg/lit at 32.5o c and aeration period of 10 h. beyond this temperature, the bod5 values increase. fig. 3 shows the effects of temperature on bod5 at various phosphate concentrations and constant aeration period of 10 h. the bod5 reaches 250 mg/lit at temperature of 32.5o c and phosphate concentration of 16.8 mg/l. fig. 4 shows the response surface function developed by the model considering temperature and aeration period. the response obtained is minimum bod5 at temperature of 32.5o c and aeration period of 10 h. it is clear that increasing in temperature from 20o c to 32.5o c, leads to an increase in the activity of microorganisms to degrade the organic material. beyond 32.5o c, the activity of microorganism decreases [12, 21]. effect of aeration period: the effects of the aeration period on the bod5 at different temperatures and phosphate concentration are shown in figs. 5 and 6, respectively. the bod5 values decrease with increasing the aeration period and reaches 250 mg/l at a temperature of 32.5o c at a fixed phosphate concentration of 16.8 mg/l (fig. 5). fig. 6, indicates that the bod5 reached a value of 250 mg/l at aeration period of 10 h and phosphate concentration of 16.8 mg/lit at constant temperature of 32.5o c. the increase in the aeration period to a certain limit lowers both the bod5 and the mlss, since there will be longer time for the microorganism to decompose the organic matter into simpler materials [4]. however, the increase in the oxygen supply above this limit, will improve the growth and reproduction of the microorganism and needed high cost for aeration basin [2]. the competition between these microorganism for nutrient, may lead to starvation and reduce the number of microorganism [22]. effect of phosphate: fig. 7 shows the influence of phosphate concentration on bod5 at different temperatures using constant aeration period of 10 h. the bod5 reaches a value of 250 mg/l at phosphate concentration of 16.8 mg/l and at a temperature of 32.5o c. fig. 8 shows the influence of phosphate concentration on bod5 at various aeration periods and constant temperature. the bod5 decreases when phosphate concentration increases up to a level of 16.8 mg/l. beyond this level, the bod5 increases slowly since more phosphate concentration helps algae growth. when these algae die and decay they give organic material which increases the bod5. thus it may be assumed that, the input of 1 mg phosphorus lead to the growth of about 100 mg of algae dry matter [22]. fig. 9 shows isometric relationship between aeration period, phosphate concentration with the bod5. the response obtained is minimum (bod5) at aeration period 10 h and phosphate concentration of 16.8 mg/l. microorganisms require certain nutrients for growth. the basic nutrients of abundance in normal raw sewage are carbon (c), nitrogen (n) and phosphate (p) with the ratio of c:n:p of approximately 100:10:1 [23]. phosphorus is an essential element, it is part of the structure of dna and rna, and is an important intermediate in metabolism [24]. bacteriological tests indicated the presence of bacteria and protozoa in the asp. the types of bacteria found on the surface after incubation were: i. staphylo cocci spp. and ii. bacilli. meanwhile, fungi did not appear on culture, since they favour ph lower than the ph of asp. applications of optimum condition for wastewater treatment plant plant: after carrying out the preliminary processes, the wastewater samples were taken from the effluent of two tanneries, with their bod5 values reduced from 760 mg/l to 610 mg/l. the optimum conditions that have been obtained above (temperature = 32.5o c; aeration period = 10 h; and phosphate concentration = 16.8 mg/l) were used for the biochemical treatment. the treatment resulted in a decrease in the bod5 form 436 mg/lit to 75 mg/l in laboratory. however, the actual bod5 value of the effluent from the first aeration basin in plant was 100 mg/l. g.a. rassoul and d.r. rzaige ijcpe vol.9 no.3 (2008) fig.2: effect of temperature on bod5 at constant phosphate level concentration (16.8mg/l) fig.3: effect of temperature on bod5 at constant aeration period (10 h). fig.4: effect of temperature and aeration period on bod5. fig.5: effect of aeration period on bod5 at constant phosphate concentration (16.8 mg/l) effect of temperature on corrosion of carbon steel boiler tubes in dilute soduim chloride solution 6 ijcpe vol.9 no.3 (2008) fig. 6: effect of aeration period on bod5 at constant temperature (32.5 °c) fig.7: effect of phosphate concentration on bod5 at constant aeration period (10 h) fig. 8: effect of phosphate concentration on bod5 at constant temperature (32.5 °c) conclusions 1. the optimum conditions for biochemical wastewater treatment the case under study were: temperature, 32.5 o c; aeration period 10 hr and phosphate concentration, 16.8 mg/l. 2. the biochemical oxygen demand value could be reduced from 436 mg/l down to a value of 30 mg/l after biochemical treatment at the application of optimum conditions. 3. only bacteria and protozoa were found as microorganisms in activated sludge, because the alkaline condition and unaeration are not suitable for the living of fungi. reference 1. fao, “united nation food and agriculture organization”, j. no. 46, 1999. 2. pictel, j.,”waste management practices, municipal, hazardous and industrial”, crc, taylor and francis, boca raton, 2005. 3. american water works association, “water quality and treatment”, 4 th ed., awwa, 1990. 4. droste, r.l., “theory and practice of water and wastewater treatment”, john, wiley and sons, n y, 1997. 5. “wastewater treatment technologies”, internet address, (http. //web mall. ucbiz. com/power/contents/water/wastewater, htm), 1999. 6. mark, j. h., “water and wastewater technology” 2nd edition, john wiley and sons inc., new york, 1986. airation period ( hr) b o d 5 (m g /l it ) 220 260 300 340 380 420 460 4.5 5.5 6.5 7.5 8.5 9.5 10.5 po 4 = 5 m g/lit p0 4 = 8.2 m g/lit po 4 = 12.5 m g/lit po 4 = 16.8 m g/lit po 4 = 20 m g/lit po 4 (mg/lit) b o d 5 ( m g /l it ) 220 280 340 400 460 520 2 6 10 14 18 22 t= 20 0 c t= 25.3 0 c t= 32.5 0 c t= 39.7 0 c t= 45 0 c po 4 ( mg/lit) b o d 5 ( m g /l it ) 220 260 300 340 380 420 460 2 6 10 14 18 22 t = 5 hr t = 6 hr t = 7.5 hr t = 9 hr t = 10 hr g.a. rassoul and d.r. rzaige ijcpe vol.9 no.3 (2008) 7. matcalfe and eddy, “wastewater engineering”, mc graw hill, inc., n.y, 1991. 8. tebbutt, t.h.y., “principles of water quality control”, 2nd edition, pergamon press ltd., london, 1977. 9. nemerow, n.l., “liquid waste of industry”, addison-wesley, publishing co., inc., united state of america, 1971. 10. kashiwaya, m and yoshimato, k., j. water poll. cont. fed., 52 (1981) 32-33. 11. watts, j. and garber, b., “respirometric control of the activated sludge process”, sensors in wastewater technology conference, 1995, internet. 12. duke, m.l., eckenfelder and templeton, m., j. water sci. technol., 14(1981), 20-22. 13. robert, j. and linda, l., “the microbiology of activated sludge”, walters kluwer co., stuttgart, 1998. 14. eye, j. d., “tannery wastes” j. water poll. cont. fed., 48 (1978) 81-83. 15. delzer, g. c. and mckenzie, s.w. “five day biological oxygen demand”, usgs twri book 9–a7, 3 rd ed., 2003. 16. negulescu, m., “municipal wastewater treatment”, elsevier, amsterdam, 1986. 17. michael, j.and arnold ,e., “standard methods for the examination of water and wastewater”, american public health association, 13th ed., 1971. 18. cappuccino, g. and sherman, n., “microbiology :laboratory manual”, benjamin/ cummings, 1987. 19. montgomery, d.c., “design and analysis of experiments”, wiley, new york, 1976. 20. wiesmann, u, choi, i. s. and dombrowsli, e., “fundamentals of biological wastewater treatment”, wiley, n y, 2006. 21. euiso, c. and euisin, l., “water sci. technol., 37 (1998) 219-220. 22. warren, j., and mark, j. hammer, “water supply and pollution control”, 4th ed., harper and row, publishers, inc., 1985. 23. kristensen, g. h., and m. henze, water sci. tech., 31 (1992)18-20. 24. rybicki, s., advanced wastewater treatment, phosphorus removal from wastewater, a literature review, report 3042, joint polish swedish reports, e. płaza, e. levlin, b. hultman, (eds). stockholm 1997. iraqi journal of chemical and petroleum engineering vol.9 no.4 (december 2008) 35-40 issn: 1997-4884 cathodic protection of copper pipes carrying saline water in the presence of aerobic bacteria aprael. s. yaro * , hala.a.k.rasheed and haider.a.k. rasheed * * chemical engineering department college of engineering university of baghdad – iraq abstract rates of zinc consumption during cathodic protection of a copper pipeline carrying saline water were measured by the loss in weight technique. the study of sacrificial anode cathodic protection of short copper tube using zinc strip extended axially in the pipe revealed that : (i) the increase of zinc consumption with time of exposure (1-3 h's) at different flow rates (turbulent flow) (300-600 l/hr) while the temperature , solution concentration and the ph were fixed at 20ºc, 3.5%wt nacl, and ph=8 respectively in absence and presence of bacteria.(ii)increase of zinc consumption with flow rates (300-600 l/hr) at different temperatures (10-40ºc) while solution concentration and time of exposure were fixed at 3.5 %wt nacl and 3hr's respectively, in absence and presence of bacteria. (iii) increase of zinc consumption with flow rates (300-600l/hr) at different solution concentrations (1-3.5 %wt nacl) while the time of exposure and temperature were fixed at 3h's and 30ºc respectively in absence and presence of bacteria. generally the zn consumption during cathodic protection ranges from (2.42426.741 g/m2) and (5.352-27.296g/m2) in absence and presence of bacteria respectively. key words: sacrificial anode, cathodic protection, seawater, pseudomonas flourescens, microbiological corrosion. introduction microbiological corrosion is the deterioration of materials caused directly or indirectly by bacteria, algae, moulds or fungi; singly or in combination. microbiological corrosion refers to corrosion and ensuing loss of metal caused by biological organisms. microbiological influenced corrosion (mic) can occur in any aqueous environments, and because of the omni present nature of microbes in fluid systems, mic is a commonly occurring phenomenon. mic is a common problem in industrial processes due to the presence of microbes, adequate nutrients and corrosive byproducts [1]. biological organisms fall under two groups based on the type of corrosion they engender: (a) anaerobic corrosion (b) aerobic corrosion. sulfate reducing bacteria (srb) from the genera desulfovibrio are a typical example of anaerobic mic. aerobic sulfur oxidizing bacteria of the type thiobacillus can create an environment of up to 10 percent sulfuric acid, thereby encouraging rapid corrosion [2]. the mechanisms potentially involved in mic are summarized as: 1-cathodic depolarization associated with anaerobic growth, whereby the cathodic rate limiting step is accelerated by micro-biological action. 2-formation of occluded surface cells, whereby microorganisms form "patchy" surface colonies. sticky polymers attract and aggregate biological and nonbiological species to produce crevices and concentration cells, the basis for accelerated attack. 3-fixing of anodic reaction sites, whereby microbiological surface colonies lead to the formation of corrosion pits, driven by microbial activity and associated with the location of these colonies. 4underdeposit acid attack, whereby corrosive attack is accelerated by acidic final products of the mic. university of baghdad college of engineering iraqi journal of chemical and petroleum engineering cathodic protection of copper pipes carrying saline water in the presence of aerobic bacteria 36 ijcpe vol.9 no.4 (2008) 5-depassivation of metal surfaces and induction of corrosion 6attack of metal by a process in which microbes and the metal cooperate to sustain the corrosion reaction. 7attack due to a combination of bacteria. 8removal of corrosion inhibitors (oxidation of nitrite or amines). [3, 2]. pseudomonas flourescens pseudomonas is a gram-negative, aerobic, rod-shaped bacterium with unipolar motility [4]. these bacteria are common inhabitants of soil and water [5].maximum activity at ph (7.5-8.5) no activity at ph 6 and below [6]. pseudomonas bacteria is now being found in heating and chilled water systems. until the last couple of years bacteria in these types of systems were of little concern and not often investigated. now a bacteria known as pseudomonas has started to appear in main water supplies, where it has no significant health concerns, but can have a major effect on the water systems in commercial buildings. pseudomonas is a biofilm or slime-producing bacteria and left to proliferate can cause severe corrosion and blockages within pipework. this particularly affects modern buildings with the small-bore pipework and small orifices associated with control valves [7]. the biofilm can reduce the water flow and provide a habitat for other corrosion inducing bacteria that will lead to pitting and leaking pipework. the net result of pseudomonas in heating and chilled water systems is a decrease in their efficiency and to increase down time and costs from occurrence of leaks. the presence of pseudomonas flourescens in artificial tap water affects the composition of the oxide layer and the susceptibility to pitting corrosion of copper and 70/30 brass. in the sterile conditions the mass loss is lower in brass than in copper while the presence of bacteria enhances the attack in brass. bigger and deeper pits can be seen in the presence of microorganisms [8].the adhesive properties of the bacterium pseudomonas flourescens to stainless steel were found to be highly dependent on surface shear stress and the time and concentration of cells used in the incubation procedure. maximum levels of adhesion occurred in zones of lowest surface shear stress [9]. apparatus and procedure: the apparatus shown in figure(1)was used to study the variables: flow rate (300-600 l/h) and time (1-3h) at fixed nacl concentration (3.5wt%) and temperature (20ºc); flow rate (300-600 l/h) and temperature (10-40ºc) at fixed nacl concentration (3.5wt%) and time (3h); and, flow rate (300-600 l/h) and nacl concentration (13.5wt%) at fixed temperature (30ºc) and time (3h) in absence and presence of bacteria .after the container vessel was filled with saline water ph (8) the nacl concentration and temperature were adjusted to the desired values. before each run, the zinc strip used as sacrificial anode was weighed and then fixed at the inlet of the copper tube by rubber stopper and was electrically connected by an insulated copper wire to the copper tube outlet .the zinc strip is extending along the copper tube to ensure uniform current and potential distribution along the tube wall.the saline water was pumped from the vessel through the rotameter to measure the desired flow rate (i.e. the saline water is circulated between the vessel and copper tube for desired time).after each run the zinc strip was rinsed in distilled water and brushed with emery paper to remove the corrosion products, dried with clean tissue then immersed in chloroxylenol, dried again, and then re-weighed to determine the weight loss. the copper tube was also rinsed and dried with clean tissue before the next run. after each run the vessel was emptied from the solution, washed with distilled water and then filled with a new prepared solution for new run. in the presence of bacteria the bacterial cells were grown in nutrient broth for 6 hours at 32 o c in a rotary shaker (120 rpm) then the absorbance of this broth was set to an 600 a° of optical density (o.d )0.15 (243x107 bacteria/cm³). [8].after the container vessel was filled with nutrient broth containing bacteria( ph (8)) , the nacl concentration and temperature were adjusted to the desired values. the inoculated broth was pumped from the vessel through the rotameter to measure the desired flow rate, then through the copper tube and returned back to the vessel (i.e. the inoculated broth is circulated between the vessel and copper tube for desired time). after each run the vessel is emptied from the solution and washed using recirculating hot water loop (greater than 90oc) to kill bacteria, then filled with a new prepared solution for new run. . aprael. s. yaro, hala.a.k.rasheed and haider.a.k. rasheed 37 fig.1: schematic diagram of apparatus used in sacrificial anode test system preparation of bacterial inoculum pure culture of pseudomonas flourescens that were used in the experiments have been taken from the department of biotecchnology. they were previously isolated from soil. pseudomonas flourescens activated on nutrient agar at 32 o c overnight. cells were harvested from cultures then inoculated into nutrient broth containing 0.5% peptic digest of animal tissue, 0.15% beef extract, 0.15% yeast extract and 0.5% sodium chloride dissolved in distilled water (ph 8) and incubated at 32 o c with rotary shaker (120 rpm) for 6 hour [8,10]. results and discussion 1time effect figures 2 and 3 show the rate of zinc consumption (dissolution), increases with increasing time at various flow rates and constant temperature (20ºc) , nacl concentration ( 3.5%)wt and ph = 8 in absence and presence of bacteria respectively. this can be attributed to the relative movement between the corrosive fluid and the metal surface *.i.e., erosion corrosion. it is important to mention here that in the presence of pseudomonas flourescens the rate of zinc consumption increases because the aerobic bacteria( pseudomonas flourescens) accelerate anodic and cathodic reactions. the anodic oxidation was enhanced by the localized acidity at the anodic sites due to the excretion of organic/inorganic acids by microorganisms [11]. increasing the time of exposure, the amount of organic and inorganic acids increases. 0.00 0.05 0.10 0.15 0.20 0.25 0.30 40 60 80 100 120 140 160 180 200 time min z in c c o n su m p ti o n m g /c m2 flow = 300l/hr flow = 400l/hr flow = 500l/hr flow = 600l/hr fig.2: zinc consumption with time for different flow rates (temperature 20 o c, nacl 3.5% and ph=8) in absence of bacteria 0.00 0.05 0.10 0.15 0.20 0.25 0.30 40 60 80 100 120 140 160 180 200 time min z in c c o n su m p ti o n m g /c m2 flow = 300l/hr flow = 400l/hr flow = 500l/hr flow = 600l/hr fig.3: zinc consumption with time in the presence of pseudomonas flourescens for different flow rates (temperature 20 o c, nacl 3.5% and ph=8) 2-temperature effect figures 4 and 5 show the effect of temperature on the rate of zinc dissolution at different flow rates and constant nacl concentration (3.5%) wt and time of exposure (3 h) in absence and presence of bacteria respectively. the increase in the rate of zinc dissolution with increasing saline water temperature (particularly from 10 to 40 o c) may be explained in terms of the following effects: cathodic protection of copper pipes carrying saline water in the presence of aerobic bacteria 38 ijcpe vol.9 no.4 (2008) 1. increasing saline water temperature leads to decrease saline water viscosity with a consequent increase in oxygen diffusivity according to stokes-einstein equation [12 and 13]: const ant t d 1 constant t d constant t d where μ is the saline water viscosity and d is the diffusivity of the dissolved oxygen. as a result of increasing the diffusivity of dissolved oxygen, the rate of mass transfer of dissolved oxygen to the cathode surface increases according to the following equation [13] : . 22 o d od c d ckj   2 with a consequence increase in the rate of zinc dissolution. where kd is mass transfer coefficient and j is mole flux of oxygen. 2. the decrease in saline water viscosity with increasing temperature improves the saline water conductivity with a consequent increase in corrosion current and the rate of corrosion [14]. 3. on the other hand, increase of temperature reduces the solubility of dissolved oxygen with a subsequent decrease in the rate of oxygen diffusion to the cathode surface and the rate of corrosion. it seems that within the present range of temperature effects 1 and 2 are predominating . 0.0 0.1 0.2 0.3 0.4 200 300 400 500 600 700 flow rate l/hr z in c c o n su m p ti o n m g /c m 2 temp. = 10 °c temp. = 20 °c temp. = 30 °c temp. = 40 °c fig.4: zinc consumption with different flow rates at different temperatures (nacl concentration 3.5% wt, and time 3 hr) in absence of bacteria. in the presences of pseudomonas flourescens the corrosion rate increases with increasing temperature until it reaches the optimum temperature ,after that the increase in temperature will decrease the bacterial effect. the maximum activity of pseudomonas flourescens at temperature (25-30ºc) [ 5]. for slime producing bacteria feron (1995) has, however, shown that an active slime layer will build up at 30ºc, but not at 40ºc. these results indicate that maximum temperature may vary somewhat depending on where on earth you are located. 0.0 0.1 0.2 0.3 0.4 200 300 400 500 600 700 flow rate l/hr z in c c o n s u m p ti o n m g /c m 2 temp. = 10 °c temp. = 20 °c temp. = 30 °c temp. = 40 °c fig. 5: zinc consumption with flow rate in the presence of pseudomonas flourescens at different temperatures (nacl concentration 3.5%wt, and time 3 hr) 3-salt effect figure 6 and 7 show the effect of salt concentration on the zinc dissolution at different flow rates and fixed time of exposure, 3h. and temperature of 30ºc in absence and presence of bacteria respectively. it can be seen from figure 6 that the dissolution rate of zinc at any flow rate increases with increasing solution concentration. the initial increase in the rate of zn dissolution with increasing solution concentration may be attributed to the increase in solution conductivity which gives rise to increasing the corrosion current and the rate of zn corrosion. the high rates of zn dissolution observed at 3.5%nacl concentration associated with high solution flow rates, may be ascribed to the increase in solution conductivity [13]. at 3.5% wt nacl concentration, maximum corrosion of carbon steel occurs due to maximum conductivity of solution and maximum o2 solubility in the solution [15]. kuntia et al [16] mentioned that changing the medium composition by the addition of sodium chloride (0.5% w/v) resulted in a faster decrease in the cell surface hydrophobicity. the formation, growth and reformation after detachment of the membraneattached biofilm were also slower in the presence of sodium chloride, confirming the cell growth studies. aprael. s. yaro, hala.a.k.rasheed and haider.a.k. rasheed 39 0 0.1 0.2 0.3 0.4 250 350 450 550 650 flow rate l/hr z in c c o n su m p ti o n m g /c m2 conc.= 1% conc.=2% conc.=2.5% conc.=3.5% fig. 6: zinc consumption with solution flow rates at fixed time of exposure, 3hr's, different solution concentrations and fixed temperature(30ºc), in absence of bacteria. 0.05 0.15 0.25 0.35 250 350 450 550 650 flow rate l/hr z in c c o n su m p ti o n m g /c m2 conc. = 1% conc. = 2% conc. = 2.5% conc. = 3.5% fig .7: zinc consumption with solution flow rates at fixed time of exposure, 3hr's,different solution concentration and fixed temperature (30ºc), in the presence of pseudomonas flourescens 4-flow rate effect figures 2, through 7 shows the effect of solution flow rate on the zinc dissolution with time, different temperatures and nacl concentrations, respectively. it can be seen from figures that the dissolution rate of zinc increases with increasing the flow rate. this may be attributed to the decrease in the thickness of hydrodynamic boundary layer and diffusion layer[17], consequently, increases the rate of oxygen diffusion[18]. the flow rate of saline water may also cause erosion which is combined with electrochemical attack. in the presence of pseudomonas flourescens the effect of flow rate is important in bacterial corrosion process because it not only affects the transfer of species to the metal surface but also influences the overall bacterial adhesion process and the transfer of nutrients to the metal surface [19]. stagnant fluid offers the lowest mass transfer rates because convective mass transfer does not exist without fluid flow. however, cell adhesion and biofilm formation may benefit from the absence of shear. at the other end, a fast moving fluid generates turbulence that provides enhanced mass transfer, but the accompanying high shear stress may prove to be harmful to the cells and may lead to the prevention of cell adhesion and thus biofilm formation. a sufficiently high shear stress may even detach an established biofilm [20]. mild fluid flow offers the most favorable environment for cell adhesion and sessile growth and it likely yields the highest mic corrosion rate [21]. 5effect of cell concentration the absorbance of the test solution was set to an a°600 of 0.5, 0.15 and 0.05 o.d (optical density) by using visible spectrophotometer . the strips were weighed and immersed in nutrient broth inoculated with bacterial suspensions of o.d 0.5,0.15 and 0.05 respectively and then inocubated overnight at 32 o c in a rotary shaker (120 rpm). then the corrosion rate was determined by weighing the zinc strips after incubation. the strip which inoculated with bacterial suspensions of o.d 0.15 gave the higher corrosion as shown in fig.8.it was reported in biofouling studies that biofilm thickness increased with a higher nutrient concentration when fluid shear held constant, biofilms act like a mass transfer barrier. nutrients,metabolites and corrosion products are transported across the biofilms, so increase the biofilm thickness increase the corrosion rate [21 ,22].figure 8 shows the effect of cell concentration on corrosion rate. 0 0.002 0.004 0.006 0.008 0.01 0.012 0.014 0 0.1 0.2 0.3 0.4 0.5 0.6 optical density lo s s i n w e ig h t( g ra m ) fig. 8: effect of cell concentration of pseudomonas flourescens on corrosion cathodic protection of copper pipes carrying saline water in the presence of aerobic bacteria 40 ijcpe vol.9 no.4 (2008) references 1pope.d and morris.e , materials performance, vol.34, p24, no.5,nace international ,may(1995). 2roberge, r. p. (1999), "handbook of corrosion engineering", copyright mcgraw-hill, 1st adition. 3shrier (1), l. l. (1994), "corrosion 1, corrosion control", 3rd edition, newnes-butterworth. 4ryan, k.j;ray, c.g ,(2004) sherris medical microbiology,4th ed., 5kenneth., todar university of wisconsin-madison, department of bacteriology, (2004). 6gonzales, b., viuna,r.,j. ,bacteria 171,2401-2405, (1989). 7toutain cm, caiazza nc, o’toole ga. (2004). molecular basis of biofilm development by pseudomonads. in: ghannoum mand o’toole ga, editors. microbial biofilms. washington dc: asm press. 43–63. 8valcarce.m.b, de sanchez.s.r, vazquez, corrosion science 47(795-809),(2004). 9duddridge .j.e, kent.c.a, laws.j.f, biochemistry group, engineering sciences division, united kingdom, (2004). 10busalmen j.p, de sanchez,s.r and schiffrin d.j, american society for microbiology, v.64(10), (1998). 11yuan.s.j, amy m.f.choong and s.o.pehkonen ,(1995) , department of chemical and biomolecular engineering, national university of singapore, singapore 117576. 12cussler, e. l., "mass transfer in fluid systems", cambridge university press, cambridge, uk,(1984). 13konsowa, a. h. and el-shazly, a. a., elsevier, desalination, 153, pp 223-226, (2002). 14r. r. zahran and g. h. sedahmed, chemical engineering department, faculty of engineering, alexandria university, alexandria 21544, egypt, 1997. 15an introduction, corrosion basics, p.151, n.a.c.e.(1984). 16kuntiya , a., nicolella, c., pyle, l. and poosaran, n. songklanakarin j. sci. technol., 27(5) : 1073-1082 , (2005). 17ross, t.k. and hitchen, b.p.l., corros.sci., 1, 65(1961). 18mahato, b.k., voora,s.k.and shemitt,l.w., corros.sci., 8,173 (1968). 19jhobalia.m.chintan, anhu, tingyue gu and srdjan nesic,athens,oh 45701,(2005). 20stoodley, z. lewandowski, j. d. boyle and h. m. lappin-scott, (2000) structural deformation of bacterial biofilms caused by short-term fluctuations in fluid shear: an in situ investigation of biofilm rheology, biotechnology and bioengineering, 65, 83-92. 21jie wen,kaili zhao,tingyue gu and srdjan nesic , athens,ohio 45701,(2005). 22characklis.w.g , marshall.k.c,and wiley, new york,pp.523-584,(1990). iraqi journal of chemical and petroleum engineering vol.18 no.3 (september 2017) 31 48 issn: 1997-4884 removal of dyes from synthetic wastewater by agriculturalwaste jenan a. al-najar p.o. box 35010, baghdad, iraq tel, e-mail jenan_iraqi@yahoo.com abstract adsorption is one of the most important technologies for the treatment of polluted water from dyes. theaim of this study is to use a low-cost adsorbent for this purpose. a novel and economical adsorbent was used to remove methyl violet dye (mv) from aqueous solutions. this adsorbent was prepared from bean peel, which is an agricultural waste. batch adsorption experiments were conducted to study the ability of the bean peel adsorbent (bpa) to remove the methyl violet (mv) dye. the effects of different variables, such as weight of the adsorbent, ph of the mv solution, initial concentration of mv, contact time and temperature, on the adsorption behaviour were studied. it was found experimentally that the time required to achieve equilibrium was 120 min for all dye concentrations (10-50 mg/l). the bpa was characterised using fourier transform infrared (ftir)before and after adsorption of the mv dye. langmuir, freundlich and temkin isotherm models were used to analyse the experimental isotherm data. the freundlich isotherm gives a better fit than the other isotherm models. the adsorption kinetic data were tested using pseudo-first-order and pseudo–second-order models. additionally, the intraparticle diffusion model was used to investigate the mechanism of the adsorption process. it was found that boundary layer diffusion (external mass transfer) is the rate-determining step. the thermodynamic parameters, including δh, δs and δg, were investigated at different temperatures (298, 313 and 323 k) and concentrations (5, 10, 20 and 30 mg/l) to understand the nature of the adsorption process. the thermodynamic study indicates that the adsorption of mv dye onto bpa is physical, exothermic and spontaneous in nature. key words: adsorption, peel beans, isotherm, kinetic model, methyl violet introduction dyes are a common group of industrial wastewater pollutants. dyes are soluble, coloured organic compounds that are used in many industries to colour clothes, paints, paper, plastic, leather, cosmetics and ceramics. the wastewater effluents from these industries contain dyes which may be potentially hazardous to aquatic life and human beings if they are discharged into the environment. since most dyes are toxic and even carcinogenic, it is important to remove these dyes from wastewater before the water is discharged into the environment [1]. university of baghdad college of engineering iraqi journal of chemical and petroleum engineering mailto:jenan_iraqi@yahoo.com removal of dyes from synthetic wastewater by agriculturalwaste 32 ijcpe vol.18 no.3 (sep. 2017) -available online at: www.iasj.net different technologies involving physical, chemical and biological treatment are used for the removal of dyes from water and wastewater, such as coagulation, filtration, reverse osmosis, ion-exchange, adsorption, chemical treatment by reduction, oxidation and neutralisation [2, 3, 4]. all these methods have advantages and disadvantages [5]. among the various methods, adsorption methods are some of the most effective and economic ways to treat water polluted with dyes [5, 6, 7]. activated carbon is one of the most widely used adsorbents for wastewater treatment because of its high capacity [8]. however, because of its high cost, there is growing interest in using inexpensive alternative materials instead of carbon. agricultural waste has little or no economic value and can be used as an alternative to activated carbon. various researchers have studied the use of low-cost materials, such as agricultural peel [9], agricultural waste [10, 11], sugarcane bagasse [12] and rice hulls [13], for the removal of dyes from aqueous solutions. these agriculture wastes can be used directly as adsorbents without any treatment [5, 8] or may be used as adsorbents after certain treatments or conversion to activated carbon [14, 15, 16]. the objective of the present work is to study the possibility of using low-cost agricultural waste (bean peel) as an adsorbent for the removal of mv dye from water. the effects of different parameters, such as ph of the solution, mass of the adsorbent, concentration of dye, contact time and temperature, on the dye removal were studied. the adsorption isotherm models, adsorption kinetics and thermodynamic parameters were also evaluated and reported. the adsorbent, bpa, was characterised using ftir analysis. materials and experimental adsorbent bean peel adsorbent (bpa) was collected from local iraqi vegetable market waste. it was washed well with distilled water to remove particles adhering to the surface, dried in an oven at 90°c for 24 hrs and powdered. the powder was then soaked in a 1 m hcl and washed with distilled water several times until the ph value reached 7, after which it was dried in the oven at 90°c for 24 hrs and sieved into two size ranges, (0.14-0.6mm) and (0.6-1mm). these two size ranges were used as adsorbents for the present study. adsorbate solution methyl violet 6b dye (mv) was used as the adsorbate. this dye was purchased from sigma-aldrich company, molecular formula – c24h28n3cl, molecular weight – 394. the dye was used directly without purification. the chemical structure of the mv dye used in the present work is shown in fig. (1). fig. 1, chemical structure of mv dye a dye stock solution of concentration 200 mg/l was prepared by dissolving 0.2 g of the dye in 1000 ml of distilled water. dye solutions of different concentrations (10, 20, 30 and 50 mg/l) were prepared by appropriate dilutions of the stock solution. jenan a. al-najar -available online at: www.iasj.net ijcpe vol.18 no.3 (sep. 2017) 33 the ph of the dye solutions was adjusted to the required value by adding a few drops of either 0.1 m hcl or 0.1m naoh. the properties of mv are illustrated in table (1). table 1, properties of mv dye properties data common name methyl violet suggested name methyl violet 6b c.i. number 42535 ionization basic maximum absorbance 583 color violet molecular formula c24h28n3cl, molecular weight 394 all chemicals and reagents used in the present study were of analytical grade. instruments a uv-1100 spectrophotometer was used to determine the concentration of the mv dye solutions from their absorbance, observed at the wavelength of maximum absorbance (λmax = 580 nm). a perkin elmer spectrum 100 ftir spectrometer was used for characterising the bpa at wave numbers 400-4000 cm -1 . batch adsorption experiments batch experiments were conducted to study the effect of different parameters, such as ph of the solution (2-12), particle diameter of bpa (0.140.6 and 0.6-1mm), weight of bpa (0.025-0.25 g), initial dye concentration (5-50 mg/l), contact time (10-180 min) and temperature (2560°c), on the adsorption of the mv dye. adsorption experiments were carried out at a temperature of 25 0 c and a ph of 7, except for experiments conducted to study the effect of temperature and ph. in a typical adsorption experiment, 50 ml of the dye solution of a given concentration was added to a 100-ml bottle containing a certain weight of bp adsorbent. the solution was agitated using a shaker at 200 rpm for an appropriate period of time. the bpa was then separated from the dye solution. the concentration of the remaining dye in solution was measured by a uv-spectrophotometer at the λmax of 580 nm. the amount of dye adsorbed at equilibrium qe (mg/g) on bpa was calculated using the following equation: w ccv q eo e )(   … (1) whereqe is the amount of mv dye adsorbed per unit weight of bpa after equilibrium (mg/g). co and ceare the initial and equilibrium concentrations ofthe mv dye (mg/l), respectively is the volume of dye solution (litter) and w is the weight of the adsorbent (g).the percentage removal of dye can be calculated as follows: 100 )( re%    o eo c cc moval … (2) the data obtained from experiments were used to study the equilibrium and kinetics models as well as to study the thermodynamics of the adsorption process. results and discussion ftir analysis ftir analysis is important for identifying the important functional groups present on the bpa surface. the ftir spectra of bpa were measured before and after adsorption to investigate the changes in the vibrational frequencies of the functional groups of the bpa due to adsorption of the mv dye. this ftir spectrum is presented in fig. (2). removal of dyes from synthetic wastewater by agriculturalwaste 34 ijcpe vol.18 no.3 (sep. 2017) -available online at: www.iasj.net as shown in fig. (2), the ftir spectrum of the adsorbent was measured within the wavenumber range of 400-4000 cm -1 . the spectrum of the adsorbent displays a number of adsorption peaks. the ftir spectrum consists of five adsorption bands: (1) the broad hydrogen band (3200-3500 cm -1 ) due to the presence of –oh groups in bpa; (2) the band (28503000 cm -1 ) corresponding to the c-h stretching region; (3) the band (16901760 cm -1 ) due to the carbonyl group c=o stretching vibration; (4) the absorption band in the range of 15001700 cm-1 corresponds to the bending vibrations of h2o molecules physically adsorbed on to bpa and the c=c vibrations; and (5) the band in the range of 1000-1320 cm-1 corresponds to the c-o bending vibrations of alcohols, carboxylic acids, esters or ethers. a reduction in the peaks can be seen after adsorption, but the peak positions still remain in the same range. this indicates that the adsorption of the mv dye onto bpa is by physical adsorption. table (2) shows the locations of functional groups on the bpa surface. fig. 2, ftir spectrum for bpa before adsorption (a) and after adsorption (b) of mv dye table 2, wavenumber (cm -1 ) for the dominant peaks of the functional groups on bpa from ftir analyses wavenu mber before adsorptio n (a), (cm -1 ) wavenumber after adsorption (b), (cm -1 ) functional groups wavenumber ranges of functional groups (cm -1 ) type of vibration 3292.15 3325.92 3100-3500 alcohols & phenols h-bonded o-h stretching 2920.41 2925.98 2850-3000 alkanes c-h stretching alkane c-h bonds 2851.61 2854.54 1728.73 1732.51 1690-1760 carboxylic acid c=o stretching carbonyl stretching 1615.9 1619.5 1500-1700 aromatics c=c bend 1015.78 1022.78 1000-1320 esters, alcohols, carboxylic, ethers c-o stretching 893.33 893.03 650-1000 alkenes =c-h bend jenan a. al-najar -available online at: www.iasj.net ijcpe vol.18 no.3 (sep. 2017) 35 effect of ph solution ph is one of the important parameters in the adsorption process, and it influences the surface charge of the adsorbent and the degree of ionisation of the dye in solution [17.18, 19, 20]. the experiment was carried out using 30 mg/l mv dye, 0.1 g bpa and ph ranging from 2 to 12. the effect of ph on the adsorption of mv dyes onto bpa is shown in fig. (3). fig. 3, the effect of ph on the adsorption of mv dye onto pb as shown in fig. (3), the adsorption of the mv dye increases as the ph increases and reaches a maximum at approximately ph 8. the same trend has been obtained by many researchers [1, 6. 17, 18, 21]. this result may be due to the cationic nature of the mv dye. at a low ph, a high concentration of hydrogen ions (h + ) is present in the solution. therefore, the positively charged mv dye molecules and hydrogen ions compete for binding sites on the adsorbent surface. this can also be explained by considering that at low ph, the surface of the adsorbent becomes more positively charged. this causes repulsion between the adsorbent and dye molecules, thus reducing the adsorption of dye on the adsorbent. other studies have reported the same conclusion [1, 18, 21]. at high ph, the surface of the adsorbent becomes more negatively charged, thus increasing the amount of dye adsorbed on its surface [1, 15, 16, 18, 22]. this indicates that the adsorption process is based on the electrostatic interaction between the positively charged mv dyes and negatively charged sites on the adsorbent surface [23, 24]. additionally, at ph 8 or more, the dye begins to precipitate, which may be due to the formation of a complex with oh. therefore, the increase of percentage removal at ph values equal to or higher than 8 is due to precipitation. on the basis of the previous observation, the ph value of approximately 7 was recommended in the present work. effect of adsorbent weight and particle size of adsorbent the effect of varying weight of bpa on the removal of mv dye from water was studied using adsorbent weights ranging from 0.025 to 0.25 g. the other experimental parameters were kept constant, using mv concentration of 30 mg/l, ph of 7 and a shaking time of 2 hrat 200 rpm. the experiment was carried out using two bpa size ranges (0.14-0.6 mm and 0.6-1 mm). the experimental data for the two size ranges are presented in fig.(4). fig. (4 a) shows the effect of the particle size of the adsorbent on the adsorption process. it is clear from this figure that the percentage removal of the mv dye increased with the decrease of particle size. this is due to the increased surface area of the bpa caused by decreasing particle size. removal of dyes from synthetic wastewater by agriculturalwaste 36 ijcpe vol.18 no.3 (sep. 2017) -available online at: www.iasj.net fig. 4, effect of adsorbent weight on the adsorption of mv dye onto bpa (30 mg/l mv dye conc., 120 sec contact time, 220 r.p.m. agitation speed, 25 ο c temp.) additionally, it can be observed from fig. (4) that the increase in the weight of the bpa causes an increase in the percentage removal of the mv dye, but a decrease in the adsorption capacity (qe). fig. (4) shows that the percentage removal increases with adsorbent weight until a value of 0.1 g, after which it reaches equilibrium. this weight gives percentage removals of 71% and 68% for the particle size ranges (0.14 0.6 mm) and (0.6 -1 mm), respectively. this may be due to the increase in the bpa surface area and the availability of adsorption sites with increasing weight of the bpa. this observation is in agreement with other previous studies [25, 21, 26, 27]. therefore, the best removal was found at the dose of 0.1 g with the particle size range (0.14-0.6 mm). effect of contact time and initial dye concentration the contact time to reach equilibrium is an important parameter in wastewater treatment [1]. to study the effect of contact time on the adsorption capacity of the bpa, experiments were carried out using a fixed weight of adsorbent (0.1 g) and various initial concentrations of the mv dye (10, 20, 30 and 50 mg/l) at a ph of 7for different time intervals (15180 min), as shown in fig. (5). fig. 5, effect of contact time and initial dye concentration on the adsorption of mv dye onto bpa (0.1 g adsorbent weight, 25 °c temperature. jenan a. al-najar -available online at: www.iasj.net ijcpe vol.18 no.3 (sep. 2017) 37 the amount of dye adsorbed, qe, at different concentrations increases rapidly in the initial stages up to60 min, after which it gradually decreases with further progress of the adsorption, finally reaching equilibrium between 60 and 120 min. after 120 min, there is no change in the adsorption capacity. the rapid adsorption in the initial stage can be attributed to the higher availability of active sites on the adsorbent surface. with the passage of time, these active sites are gradually occupied by dye molecules, which lead to a decrease in the number of active sites available for the residual dye molecules in solution. similar behaviour has been reported in previous literature [12, 15, 27, 28, 29]. therefore, the contact time required for the bpa to reach equilibrium is 120 min for different initial dye concentrations, and this time was set as the agitation time for adsorption studies. adsorption isotherm studies the adsorption isotherm provides a representation of the adsorption process through an equation or curve relating the number of dye molecules adsorbed onto the surface of an adsorbent (qe) to the equilibrium concentration of dye molecules in solution (ce) at a constant temperature. several isotherm models were employed to describe the adsorption process. the fits of the langmuir, freundlich and temkin adsorption isotherm models were investigated in order to model the experimental data of adsorption of the mv dye on the bpa. 1langmuir isotherm model was developed by irving langmuir in 1916 [30]. this model is based on the following assumptions: (1) molecules are adsorbed as a monolayer; (2) the surface of the adsorbent is homogeneous; (3) all adsorption sites are identical and energetically equivalent; (4) each site can accommodate only one molecule; there is no interaction between adsorbed molecules [1, 28, 29]. the linear form of the langmuir isotherm model is expressed by langmuir [30]. maxmax 1 q c bqq c e e e  … (3) where, qmax is the maximum capacity (mg/g) and b is the langmuir equilibrium constant (l/mg). the experimental isotherm data were correlated using the langmuir model, eq. (3), as shown in fig. (6). the linear plot of ce/qe against ce indicates that the adsorption of mv dye onto bpa follows the langmuir isotherm model. fig. 6, linear plot of langmuir isotherm model for the adsorption of mv dye onto bpa (25 °c temperature) the langmuir constants, qmax and b, were calculated from the slope and intercept of the linear plot. the langmuir constants with correlation coefficients are tabulated in table 3. removal of dyes from synthetic wastewater by agriculturalwaste 38 ijcpe vol.18 no.3 (sep. 2017) -available online at: www.iasj.net the type of adsorption isotherm can be determined using the dimensionless parameter (rl), known as the separation factor. using the value of b deduced from the langmuir model, rl can be calculated using the following equation [15, 17, 27, 31]. o l bc r   1 1 … (4) where co is the initial mv dye concentration. the value of rl indicates the following types of isotherms: irreversible if rl = 0, favourable if 0 < rl <1, linear if rl = 1, unfavourable if rl>1[1, 15, 27, 32]. rl values were calculated at different mv dye concentrations, and their values are listed in table (3). the values are in the range of 0.37940.8106, which indicates that the adsorption process is favourable, as shown in table 3. additionally, the change of rl with mv dye concentration is presented in fig. (7). fig. 7, change of separation factor, rl, with initial mv dye concentration this figure shows that when the dye concentration is increased, a value of rl close to zero means that the adsorption of dye is less favourable at high initial dye concentrations. this is consistent with reports from previous research [32]. 2freundlich isotherm model empirical equation that is commonly used to describe multilayer adsorption ona heterogeneous surface. the linear form of the equation is represented by freundlich [33]. efe c n kq log 1 loglog  … (5) where kf is the freundlich constant related to adsorption capacity (mg/g)(l/mg) 1/2 and n is the freundlich constant related to the adsorption intensity. the freundlich isotherm was applied to the experimental data, and the freundlich constants, kf and n, were determined from the linear plot of log qe against log ce, as shown in fig. (8). fig. 8, linear plot of freundlich isotherm model for the adsorption of mv dye onto bpa (25 °c temperature) the freundlich constants with the correlation coefficient are tabulated in table (3). the value of n indicates the adequacy of the adsorption process as follows: unfavourable adsorption if n < 1, linear adsorption if n =1, favourable adsorption if n > 1 [34]. in the present work, the value of n is greater than unity (n = 1.135), indicating that the adsorption process of the mv dye on the bpa is favourable. jenan a. al-najar -available online at: www.iasj.net ijcpe vol.18 no.3 (sep. 2017) 39 table 3, the langmuir, freundlich and temkin isotherms constants and correlation coefficients for adsorption of mv dye onto bpa at 25 ο c models isotherm parameter langmuir isotherm qmax, (mg/g) b, (l/mg) rl, (l/mg) r 2 84.034 0.0234 0.3794-0.8106 0.9584 freundlich isotherm kf, (mg/g)(l/mg) 1/ 2 1/n n r2 2.090 0.8813 1.135 0.9999 temkin isotherm α(l/g) β (kj/mol) r² 0.716 7.836 0.9322 3temkin isotherm model this model takes into account the effects of direct interactions between the adsorbent and adsorbate (mv dye) on the adsorption isotherm, and assumes that as the surface is covered with a layer of the adsorbate molecules, the heat of adsorption of all molecules in the layer decreases linearly with coverage due to this interaction [35, 36]. the linear form of the temkin isotherm is expressed by ee cq lnln   … (6) t b rt  where α is the temkin isotherm constant (l/g), βis the temkin constant related to the heat of adsorption (j/mol), r is the gas constant (8.314 j/mol. k),t is the temperature (k) and bt is the temkin isotherm constant. the temkin isotherm (eq.6) was used to analyse the experimental data and the temkin isotherm constants, α and β were determined from the linear plot of qe versus lnce, as shown in fig. (9). the temkin constants with correlation coefficients are listed in table (3). fig. 9, linear plot of temkin isotherm model for the adsorption of mv dye onto bpa (25 °c temperature) the correlation coefficients for all isotherm models studied are tabulated in table (3).the correlation coefficient (r 2 = 0.9999) for the freundlich model is greater than those of the other models (r 2 = 0.9584and r 2 = 0.9322), that is, the langmuir and temkin isotherm models, respectively. these results indicate that the freundlich isotherm model gives the best fit to the experimental data, and therefore, the adsorption of the mv dye on the bean peel is best described by the freundlich isotherm model. the fitting of experimental data with the freundlich isotherm has been reported by previous researchers using natural materials for the adsorption of dyes [8, 34]. removal of dyes from synthetic wastewater by agriculturalwaste 40 ijcpe vol.18 no.3 (sep. 2017) -available online at: www.iasj.net depending on the assumptions of the freundlich isotherm model, the adsorption process may be physical adsorption as well as multilayer adsorption with a heterogeneous distribution of active sites on the bpa surface [34]. the maximum adsorption capacity obtained (qmax) is 84.03 mg/g. the value of the constant n is greater than unity, indicating that adsorption process of the present work is favourable. adsorption kinetics studies kinetic studies are important to determine the rate-controlling step of the adsorption process. this is an important parameter for selecting the optimal operating conditions required during the design of the adsorption process [21, 27]. the kinetic study involves studying the effect of contact time on the adsorption of the mv dye at a given initial dye concentration, as shown in fig. (5). in the present work, kinetic studies were carried out at different initial dye concentrations. two kinetic models were utilised to analyse the experimental data in the present study, including the pseudo-first-order and pseudo-second-order kinetic models at different initial dye concentrations. 1pseudo-first-order kinetic model this model was presented by lagergren [37]. the linear form of this model is given by t k qqq ete 303.2 log)log( 1 … (7) where qe and qt are the amounts of the mv dye adsorbed on the bpa (mg/g) at equilibrium and at time t, respectively, and k1 is the rate constant (min -1 ) of the pseudo-first-order model. the plot of log (qe-qt) versus t (eq. 7) should be linear as shown in fig. (10). fig.10, pseudo-first-order kinetics for adsorption of mv dye onto bean peel adsorbent the values of k1 and qe were determined from the slope and the intercept of the plot, respectively, and are tabulated in table (4) along with the corresponding correlation coefficients. table 4, kinetic parameters and correlation coefficients for adsorption of mv dye onto bpa at different initial concentrations of mv dye (0.1 g adsorbent, 25°c and ph 7). co (mg/l) qe,exp (mg/g) pseudo first-order pseudo second-order qe,cal(mg/g) k1 (min -1 ) r1 2 qe,cal(mg /g) k2 (g/mg.min) r2 2 10 4.100 1.009 0.0074 0.614 3.879 0.0504 0.999 20 7.688 3.752 0.0440 0.986 8.000 0.0205 0.999 30 9.896 7.019 0.0497 0.854 10.593 0.0089 0.996 40 13.885 13.646 0.0359 0.978 15.291 0.0038 0.999 50 17.941 17.104 0.0504 0.981 19.417 0.0042 0.996 jenan a. al-najar -available online at: www.iasj.net ijcpe vol.18 no.3 (sep. 2017) 41 2pseudo-second-order kinetic model the second-order lagergren model was presented by ho and mckay [38]. the linear form of this model is expressed by t qqkq t eet 11 2 2  … (8) where k2 is the rate constant of the pseudo-second-order model (g/mg.min). the experimental data obtained for the adsorption of the mv dye onto the bpa were fitted to eq.8, by plotting t/qt versus t, as shown in fig. (11). fig. 11, pseudo-second-order kinetics for adsorption of mv dye onto bpa the plot should be linear with a slope of 1/qe and an intercept of 1/k2qe 2 . the values of k2 and qe are calculated from the slope and the intercept of fig. (11) and are listed in table 4along with the corresponding correlation coefficient. as seen in table (4), the correlation coefficients of the pseudo-first-order kinetics model (r1 2 ) were found to be in the range from 0.61 to 0.986. therefore, this model did not fit well with the experimental data of the adsorption. additionally, it was found that at low concentrations, the calculated qe values do not agree with the experimental qe values. however, there is an agreement at higher concentrations. this confirms that the adsorption of the mv dye onto the bpa does not follow pseudo-firstorder kinetics at low concentrations. the same observation was reported by [32]. the pseudo-second-order model is used to investigate whether the ratelimiting step controlling the adsorption process is surface adsorption involving a chemical reaction (chemisorption) [39, 40]. fits of the experimental data to this model indicate that adsorption is controlled by a chemical reaction if the following conditions are met [41]: the rate constant k2 should be constant for different initial concentrations of adsorbate. the rate constant k2 should be constant with particle size. the rate constant k2 is sometimes independent of the agitation speed. if any of the above conditions are not satisfied, then the adsorption process is not controlled by chemisorption even if the experimental data are well-fitted to the pseudo-second-order kinetics model. as observed from table (4), the values of the correlation coefficient, r2 2 , of the pseudo-second-order kinetics were found to be in the range of 0.996 to 0.999, which is greater than that of the first-order model. additionally, it can be observed from table (4) that there is an agreement between the experimental and the calculated qe values for the pseudosecond-order kinetics model for all concentrations. these observations indicate that the adsorption of the mv dye onto the bpa follows pseudosecond-order kinetics, which may be due to chemisorptions. however, from table (4), the values of the rate constant k2 are not constant overall initial concentrations of the mv dye. this removal of dyes from synthetic wastewater by agriculturalwaste 42 ijcpe vol.18 no.3 (sep. 2017) -available online at: www.iasj.net change in k2 values with initial concentration confirms that the ratelimiting step is not chemisorption even though the experimental data give good fits to the kinetic model. adsorption mechanism one of the kinetics models used to determine the mechanism of adsorption is the intraparticle diffusion model. intraparticle diffusion model intraparticle diffusion model was described by weber and morris [42]. the linear form of this model is represented by ctkq idt  2/1 … (9) where kid is the intraparticle diffusion rate constant (mg/g min 1/2 ) and c is the intercept, indicating the boundary layer effect. a plot of qt against t 1/2 should give a straight line with the slope kd and the intercept c. intraparticle diffusion is considered as the ratedetermining step if the plot is linear and the intercept c is zero [34]. if the intercept c is not zero, then external diffusion is involved in the adsorption process in addition to intraparticle diffusion. fig. (12) shows the plot of qt against t 1/2 for the adsorption of the mv dye onto the bpa at different concentrations. fig. 12, intraparticle diffusion kinetics for adsorption of mv dye onto bpa at different initial concentration of mv dye (0.1 g adsorbent, 25 ο c and ph 7). table 5, intraparticle diffusion coefficient kinetics parameters for the adsorption of mv dye onto bpa at different mv dye concentrations (0.1 g adsorbent, 25 ο c and ph 7) conc 1 st linear line 2 nd linear line kd (m/g.min 1/2 ) c (mg/g) r² kd (m/g.min 1/2 ) c (mg/g) r² 10 0.2809 1.6156 0.886 0.0103 3.6225 0.8995 20 0.7688 1.8788 0.8279 0.0306 7.289 0.8916 30 0.9223 2.2928 0.9897 0.0978 8.6224 0.9549 40 1.3921 2.4637 1.000 0.1087 12.396 0.9943 50 1.879 3.0622 0.9677 0.116 16.457 0.8955 this figure shows that the plots consist of double linear portions. this observation indicates that the adsorption process follows two stages of mass transfer. the initial linear portion of the plot covering the time range between 15 to 30 min is attributed to boundary layer diffusion (external mass transfer) [43]. conversely, the second linear portion after 30 min is due to intraparticle diffusion or pore diffusion. the linearity of the plots confirms that intraparticle diffusion plays an important role in the adsorption process, but none of the plots in fig. (12) pass through the origin. this indicates that intraparticle diffusion is not the rate-controlling step. it is jenan a. al-najar -available online at: www.iasj.net ijcpe vol.18 no.3 (sep. 2017) 43 concluded that external mass transfer (boundary layer diffusion) may be the rate-controlling step. this is in agreement with the results reported in the literature [12, 14, 22] for the adsorption of dyes by an agricultural material. the values of kid and c were obtained from the slope and the intercept of the double linear plots of fig. (12), respectively. these values are listed in table 5. adsorption thermodynamic in environmental engineering practice, thermodynamic parameters must be considered in order to determine the nature of the adsorption process. these thermodynamic parameters, such as the change in gibbs free energy (δg ο ) (kj/mol), change in enthalpy of adsorption (δh ο ) (kj/mol) and change in entropy (δs ο ) (j/mol.k),were calculated using the following equations [17, 27]. c o krtg ln … (10) where t is the absolute temperature in kelvin, r is the gas constant and kc is the adsorption equilibrium constant, which was calculated using the following equation [17, 21, 12]. e e liquid solid c c q c c k  … (11) where qe and ce are the equilibrium concentrations of the mv dye in the solid phase (adsorbent) (mg/g) and in the liquid phase (dye solution) (mg/l). the enthalpy change (δh ο ) and entropy change (δs ο ) were calculated using the van’t hoff equation, as follows tr h r s k oo c 1 ln     … (12) where sthg  eq. (11) was applied to the experimental data of the adsorption of the mv dye onto the bpa, to calculate kc at different temperatures (25, 40, 50 and 60 ο c) and at different concentrations of mv dye (10, 20 and 50 mg/l). the plot of lnkc versus 1/t (eq.12) gives a straight line, as shown in fig. (13). table 6, thermodynamic parameters for the adsorption of mv dye onto bpa conc. mg/l δh kj/mol δs j/mol.k δg kj/mol δg kj/mol δg kj/mol δg kj/mol kc kc kc kc 298 313 323 333 298 313 323 333 5 -3.705 -10.981 -0.417 -0.301 -0.149 -0.038 1.18 1.12 1.06 1.01 10 -3.216 -9.034 -0.49 -0.43 -0.32 -0.17 1.22 1.18 1.13 1.06 20 -3.056 -7.606 -0.79 -0.69 -0.57 -0.54 1.38 1.30 1.24 1.21 50 -2.867 -6.334 -0.96 -0.92 -0.82 -0.74 1.47 1.42 1.36 1.31 removal of dyes from synthetic wastewater by agriculturalwaste 44 ijcpe vol.18 no.3 (sep. 2017) -available online at: www.iasj.net fig. 13, the van’t hoff plot for adsorption of mv dye onto bpa at different initial concentrations of mv dye (0.1 g adsorbent and ph 7) the gibbs free energy change (δg ο ) was calculated from eqs.(10) and (11). the enthalpy change (δh ο ) and entropy change (δs ο ) were calculated from the slope and the intercept, respectively, of the plot in fig. (13). the values of the parameters at different temperatures and concentrations are listed in table (6). the negative values of δg ο shown in table (6) confirm that the adsorption of the mv dye onto the bpa is thermodynamically favoured, and the adsorption process is spontaneous under the experimental conditions. additionally, the value of δg ο increases with increasing temperature, indicating that the degree of spontaneity increases at higher temperatures. the negative values of δs ο indicate the decrease in the disorder of the system. the negative values of δh ο indicate that the adsorption process is exothermic. the absolute value of δh ο may be used to determine whether the nature of adsorption is chemical or physical. for chemical sorption, the values of δh ο range from 83 to 830 kj/mol while for physical sorption, they range from 8 to 25 kj/mol [34]. as seen in table (6), their absolute values were less than 8 kj/mol. this suggests that the adsorption process may be physical in nature. additionally, the small values of δh ο confirm that the adsorption of the mv dye onto the bpa occurs by physical adsorption. it was suggested in previous work that if the δh ο values are less than 40 kj/mol, then the adsorption process should be considered as physisorption [27, 44]. conclusions 1bpa shows good effectiveness for the removal of mv dye from aqueous solutions in the presently reported conditions. 2 it was found that a ph value of 7 provides the best removal under the present conditions. 3the percentage removal of mv dye (% r) increases significantly by increasing the dose and the size of the adsorbent (bpa), it was found under the present conditions that 0.1 g adsorbent is the best dose, resulting in the best percentage removal (71%) and best capacity (10.5 mg/g). 4the amount of dye adsorbed increases with the increase in the contact time and reaches equilibrium after approximately 120 min. additionally, it increases with the increase in the initial mv dye concentration. 5the adsorption isotherm data of the mv dye fit well to the freundlich isotherm. therefore, the adsorption occurs by a physical process as well as multilayer sorption on the heterogeneous surface. 6the maximum adsorption capacity (qe,max) is calculated from the langmuir model and found to be 84.034 mg/g . 7the n value is greater than unity (n > 1) from the freundlich isotherm jenan a. al-najar -available online at: www.iasj.net ijcpe vol.18 no.3 (sep. 2017) 45 and 0 < rl < 1 from the langmuir isotherm, indicating that the adsorption of the mv dye onto the bpa is favourable. 8the pseudo-second-order kinetic model provides a good description of the kinetic experimental data for mv dye adsorption onto bpa, and the experimental value of the adsorption capacity, qe,exp, is very close to the calculated value, qe,cal. 9the fitting of the experimental data with the pseudo-second-order kinetics model indicates that the adsorption process is chemisorption. however, the values of the rate constant k2are not constant for all initial concentrations of the mv dye.this confirms that the rate-limiting step is not chemisorptions, even though the experimental data gives provide a good fit to the kinetic model. 10the application of the intraparticle diffusion model to the adsorption data indicates that the adsorption process is initially controlled by boundary layer diffusion and, finally, by intraparticle diffusion. however, boundary layer adsorption is the rate-limiting step. 11the negative values of δh ο and δg ο indicate that the adsorption process is exothermic, thermodynamically favoured and spontaneous in nature. additionally, the negative values of δs ο indicate the decrease in the disorder of the system.the small values of δh ο indicate that the adsorption process is physical in nature. acknowledgements i thank prof. thamer, the head of the chemical engineering department/ university of technology in iraq, for providing the space and facilities needed to complete the requirements of my research. additionally, my deep thanks to prof. adel o. sharif from the university of surrey in the uk, for providing me with some modern literature related to my research. nomenclature bpa bean peel adsorbent b langmuir equilibrium constant l/mg c intraparticle diffusion constant mg/g ce equilibrium liquidphase dye concentration mg/l ftir fourier transform infrared co initial dye concentration mg/l δg ο gibbs free energy change of adsorption kj/mol δh ο enthalpy change of adsorption kj/mol k1 the rate constant of the pseudo-first order model min -1 k2 the rate constant of the pseudo-second order model g/mg.min kc thermodynamic equilibrium constant l/g kf freundlich constant related to adsorption capacity (mg/g)(l/mg) 1/2 kid intraparticle diffusion rate constant mg/g min1/2 mv methyl violet n freundlich constant related to adsorption intensity qe equilibrium solid-phase dye concentration mg/g qt the intraparticle diffusion rate constant qmax maximum capacity (mg/g) r universal gas constant 8.314 j/mol.k rl dimensionless constantseparation factor r 2 correlation coefficient δs ο entropy change of adsorption j/mol.k t temperature k t time min v dye solution volume l w weight of the bpa g α temkin isotherm constant l/g β temkin constants related to the heat of adsorption j/mol removal of dyes from synthetic wastewater by agriculturalwaste 46 ijcpe vol.18 no.3 (sep. 2017) -available online at: www.iasj.net references 1depci,t., kul,a.r., onal,y., disli,e., alkan,s. and turkmenoglu, z.f., (2012), “adsorption crystal violet from aqueous solution on activated carbon derived from golbasilignite“, physicochem. probl. miner process. 48, (1), 253279. 2mane,r.s. and bhusari,v.n., (2012), “removal of colour (dyes) from textile effluent by adsorption using orange and banana peel”, international journal of engineering research and applications, 2 (3), 1997-2004. 3al-shuwaiki, dr. n., abid, dr. b.a. and brbooti, dr.m.m., (2013), “color removal from industrial textile wastewater using chemical adsorption” eng. & tech. journal 31,part (b), (4), 471-489. 4al-husseiny, h.a., (2014), “adsorption of methylene blue dye using low cost adsorbent of sawdust: batch and continues studies” j. babylon university / engineering sciences/ 22 (2), 296310. 5dawood, s. and sen, t.k., (2014), “review on dye removal from its aqueous solution into alternative cost effective and non-conventional adsorbents” j. chem. proc. eng. 104, 1-4. 6taha, dr. d. n., mohammed,l. a., farhood, a.s. and ali,i.n.a., “2014.adsorption of janus green b dye from industrial waste water on the pistachio shells”, eng. &tech. journal 32, part (a), (13), 3106-3119. 7malarvizhi, r. and ho, y.s., (2010), “the influence of ph and the structure of the dye molecules on adsorption isotherm modeling using activated carbon”, desalination 264, 97-101. 8annadurai, g., juang, r.-s.and lee, d.-j., (2002), “use of cellulose-based wastes for adsorption of dyes from aqueous solutions” j. of hazardous materials, b92, 263–274. 9anastopoulos, i. and kyzas, g. z., (2014), “agricultural peels for dye adsorption: a review of recent literature” j. molecular liquids 200, 381-389. 10eng. khoo, c. and ong, s.-t., (2011), “utilization of agricultural waste as a biosorbent for the removal of dyes from aqueous solution” 1st world sustainability forum 1-30, www. wsforum.org. 11suteu, d., zaharia, c. and badeanu, m., (2010), “agriculture wastes used as sorbents for dyes removal from aqueous environments”, lucrări ştiinţifice, seriaagronomie 53 (1), 140-145. 12sharma, n. and nandi, b.k., (2013), “utilization of sugarcane baggase, an agricultural waste to remove malachite green dye from aqueous solutions”, j. mater. environ. sci. 4 (6), 1052-1065. 13hassan, a.a. and abdulhussein, h.a., (2015), “methyl red dye removal from aqueous solution by adsorption on rice hulls”, j. babylon university/engineering sciences 23 (2). 14ibrahim, t., moctar, b.l., tomkouani, k., gbandi, d.-b., victor, d.k. and phinthè, n., (2014), “kinetics of the adsorption of anionic and cationic dyes in aqueous solution by low-cost activated carbons prepared from sea cake and cotton cake”, american chemical science journal 4(1), 38-57. jenan a. al-najar -available online at: www.iasj.net ijcpe vol.18 no.3 (sep. 2017) 47 15shanker, m. and chinniagounder, th., (2012), “adsorption of reactive dye using low cost adsorbent: cocoa (theobroma cacao) shell. world”, journal of applied environmental chemistry 1, (1), 22-29. 16macedo, j. de s., júnior,n.b.da c., almeida, l.e., vieira, e.f. da s., cestari, a.r., gimenez, i. de f., carreño, n.l.v. and barreto, l.s., (2006), “kinetic and calorimetric study of the adsorption of dyes on mesoporous activated carbon prepared from coconut coir dust”, journal of colloid and interface science 298, 515–522. 17mahalakshmi, k., suja, s.k., yazhini, k., mathiya, s. and kalaivani, g. j., (2014). “a novel approach to investigate adsorption of crystal violet from aqueous solutions using peels of annona squamosal”, iranica journal of energy & environment 5 (2), 113123. 18kant, a., gaijon, p. and nadeem, u., (2014), “adsorption equilibrium and kinetics of crystal violet dye from aqueous media onto waste material” chemsci rev lett, 3(11s), 1-13. 19hamza, m.o., kareem, s.h., (2012), “adsorption of direct yellow 4 dye on the silica prepared from locally available sodium silicate”, eng. & tech. jornal 30 (15). 2609-2625. 20pengthamkeerati, p., satapanajaru,t. and singchan, o., (2008), “sorption of reactive dye from aqueous solution on biomass fly ash” j. hazard. mater 153, 1149–1156. 21banerjee, k., ramesh, s.t., gandhimathi, r., nidheesh, p.v. and bharathi, k.s., (2012), “a novel agricultural waste adsorbent, watermelon shell for the removal of copper from aqueous solutions”, iranica journal of energy & environment 3 (2), 143-156. 22abd el-latif, m.m., ibrahim a.m. and el-kady, m.f., (2010), “adsorption equilibrium, kinetics and thermodynamics of methylene blue from aqueous solutions using biopolymer oak sawdust composite” journal of american science 6(6), 267-283. 23hameed, b.h. and el-khaiary, m.i., (2008), “removal of basic dye from aqueous medium using a novel agricultural waste material: pumpkin seed hull” journal of hazardous materials 155(3), 601609. 24mohanty, k., naidu, j.t., meikap, b.c. and biswas, m.n., (2006), “removal of crystal violet from wastewater by activated carbons prepared from rice husk. industrial and engineering chemistry research” 45(14), 51655171. 25azhar, s.s., liew, a. g., suhardy, d., hafiz, k.f. and hatim, m.d.i., (2005), “dye removal from aqueous solution by using adsorption on treated sugarcane bagasse”, american journal of applied sciences 2 (11), 1499-1503. 26garcía, e.r., medina, r.l., lozano, m.m., pérez, i.h., valero, m.j. and franco, a.m.m., (2014), “adsorption of azo-dye orange ii from aqueous solutions using a metal-organic framework material: ironbenzene tricarboxylate”, material 7, 8037-8057. 27amin, n.k., (2009), “removal of direct blue-106 dye from aqueous solution using new activated carbons developed from pomegranate peel: adsorption equilibrium and kinetics”, j. hazard. mat. 165(1-3), 52-62. removal of dyes from synthetic wastewater by agriculturalwaste 48 ijcpe vol.18 no.3 (sep. 2017) -available online at: www.iasj.net 28tian, y., jin, c., zhao, m., xu, m. and zhang, y.s., (2010), “preparation and characterization of baker’s yeast modified by nanofe3o4: application of biosorption of methyl violet in aqueous solution”, chem. eng. j. 165 (2), 474–481. 29langmuir, i., (1916), “the constitution and fundamental properties of solids and liquids”, part i. solids. j. am. chem. soc. 38 (11), 2221-2295. 30foo, k.y. and hameed, b.h., (2012), “insight into the modeling of adsorption isotherm”, chem. eng. j. 156, 2-10. 31zhenga,h., liu,d., zheng,y., liang,s. and liu,z., (2009), “sorption isotherm and kinetic modeling of aniline on crbentonite”, j. hazard. mat., 167, 141-147. 32freundlich, h.m.f., (1906), “over the adsorption in solution:, j. phys. chem. 57, 385-470. 33vijayakumar, g., tamilarasan, r. and dharmendirakumar, m., (2012), “adsorption, kinetic, equilibrium and thermodynamic studies on the removal of basic dye rhodamine-b from aqueous solution by the use of natural adsorbent perlite” j. mater. environ. sci. 3 (1), 157-170. 34temkin, m.j. andpyzhev, v., (1940), “recent modifications to langmuir isotherms” acta physiochim., urss 12, 217–222. 35oyelude, e.o., frimpong, f. and dawson, d., (2015), “studies on the removal of basic fuchsin dye from aqueous solution by hcl treated malted sorghum mash” j. mater. environ. sci. 6 (4), 11261136. 36lagergren, s., (1898), “.zur theories der sogenannten adsorption gelosterstoffe, handlingar”, 24 (4), 1–39. 37ho, y.s. and mckay, g., (1999), “pseudo-second order model for sorption processes”, process biochem 34, 451–465. 38robati, d. , (2013), “pseudosecond-order kinetic equations for modeling adsorption systems for removal of lead ions using multiwalled carbon nanotube”, j.nanostructure in chemistry, 3:55 (2013). 39wang, h., zhou, a., peng, f., yu, h. and yang, j., (2007), “mechanism study on adsorption of acidified multiwalled carbon nanotubes to pb(ii)”, j. colloid interface sci., 316, 277–283. 40zendelska, a., golomeova, m., blazev, k., krstev, b., golomeov, b. and krstev, a., (2014), “kinetic studies of zinc ions removal from aqueous solution by adsorption on natural zeolite” international journal of science, environment and technology, 3 (4), 1303 – 1318. 41weber, jr, w.j and morris, j.c., (1963), “kinetics of adsorption on carbon from solution.j.sanitary eng. sivision”, am. soc. civil eng. 89, 31–59 42nethaji, s., sivasamy, a. and mandal, a. b., (2013), “adsorption isotherms, kinetics and mechanism for the adsorption of cationic and anionic dyes onto carbonaceous particles prepared from juglansregia shell biomass”, int. j. environ. sci. technol 10, 231–242. 43kara, m., yuzer, h., sabah,e. and celik, m.s., (2003), “adsorption of cobalt from aqueous solutions onto sepiolite”, water research 37, 224–232. iraqi journal of chemical and petroleum engineering vol.15 no.1 (march 2014) 6572 issn: 1997-4884 adsorption of methyl green dye onto bamboo in batch and continuous system ahmed adnan atshan chemical engineering departmentcollege of engineeringal-nahrain university abstract adsorption techniques are widely used to remove certain classes of pollutants from waters, especially those that are not easily biodegradable. dyes represent one of the problematic groups. the removal of methyl green from waste water using bamboo was studied in batch and continuous system. in batch system equilibrium time and adsorption isotherm was studied at different concentrations (5, 10, 15, 20, 25 and 30 ppm) and 50 mg weight of adsorbent. langmuir and freundlich equations were applied for adsorption isotherm data. langmiur equation was fitted better than freundlich equation (r 2 =0.984 for langmuir equation).the maximum percentage dye removal obtained 79.4% and adsorption capacity was 15.5 mg/g. for continuous system the breakthrough curve was studied at different bed depths (1, 2 and 4 cm), different concentrations (5 and 10 ppm), and different flow rates (5 and 10 ml/min). keywords: adsorption isotherm, methyl green, bamboo, fixed bed column. introduction the waste water disposed by textile industries is causing major hazards to the environment and drinking water due to presence of large number of contaminants like acids, bases, toxic,organic, inorganic,dissolved solids and colour.in effect,the discharge of contaminents such as dyes in the environment is worring for both toxicological and esthetical reasons as damage the qualityof the receiving streams and is toxic to food chain organisms.these colored compounds are not only aestheyically displeasing but also inhibiting sunlight into the stream and reducing the photosynthesis reaction.since many organic dyes are harmful to human beings,the removal of colourfrom process or waste effluents becomes environmentally important [1]. various physical and chemical methods have been employed for the removal of such colored effluent from water.these include coagulation [2], reverseosmosis [3], photo-degradation [4], electrochemical oxidation [5], ozonation [6] and adsorption, etc. adsorption is ,however,more popular among all these methods because of its low cost ,simple design, easy operation and the possibility of adsorbent recycling [7]. most commercial systems currently use activated carbon as sorbent to remove dyes in wastewater,which is an expensive material. adsorption of dyes on various materials have been extensively iraqi journal of chemical and petroleum engineering university of baghdad college of engineering adsorption of methyl green dye onto bamboo in batch and continuous system 66 ijcpe vol.15 no.1 (march 2014) -available online at: www.iasj.net investigated,and activated carbon has proved the most effective because of its high specific surface area,high adsorption capacity and low selectivity for both ionic and non ionic dyes [8]. recently, in order to decrease the cost of treatment,attempts have been made to find inexpensive alternative adsorbents. many non –conventional low-cost adsorbents,including natural materials, biosorbents, and waste materials from industry and agriculture,have been proposed by several workers. these materials could be used as sorbents for the removal of dyes from solution. some of the reported sorbents include clay materials [9], zeolites [11], siliceous material [10] agricultural wastes [12], industrial waste products [13], biosorbents [14] and other [15]. the aim of this work is to evaluate the adsorption capacity of bamboo in removing methyl green from aqueous solutions in batch and continuous system.in batch system study the effect of equilibrium time, initial concentration and adsorption isotherm. for continuous adsorption study the breakthrough curve at different bed depth,initial concentration and flowrate. expermental 1. adsorbate methyl green dye was used simulated waste water as adsorbate,the chemical formula c26h33n3cl2 , molecular weight = 458.5g/mol, λmax =203 nm (measured by uv), the chemical structure of methyl green is shown as in figure 1. fig. 1, chemical structure of methyl green dye stock solution (100ppm) was prepared by dissolving a certain amount of methyl green (0.1 gram) in distilled water (1 liter), and then dilutes the stock solution to give the appropriate concentrations. 2. adsorbent the main constituents of bamboo culms are holocellulose (60-70%), pentosans (20-25%), hemicellulose and lignin (each amounted to about 2030%) and minor constituents like resins, tannins, waxes and inorganic salts [16]. the moisture content of bamboo 50-60% depending on the felling season, area of growth and species. ash content (1-3%). bulk density was measured 0.231g/ml. surface area was calculated 79.652 m 2 /g. bamboo was used as adsorbent because of its high abundance, availability and can be obtained from the river. the adsorbent washing with distilled water, grinding with mill, sieving with 200µm, then washing and drying in oven at temperature 45 ˚c for 2 hours. 3. experimental procedure 3.1. batch system bamboo was washed in distilled water repeatedly until cleaned then filtered with filter paper. batch experiments were carried out in a shaker using 6 flasks containing 50 ml of dye solution at different initial concentration (5, 10, 15, 20, 25 and 30 ppm). the adsorbent (50 mg) was added to each flask and closed it .the shaker was operating at 100 rpm and withdrawal the sample after different intervals time then separating the adsorbent from the solution by centrifuge device then dye concentration was measured by uv. the wave length was measured at λmax =203 nm. ahmed adnan atshan -available online at: www.iasj.net ijcpe vol.15 no.1 (march 2014) 67 the adsorption capacity of dyes (mg/g), (qt), on bamboo was calculated from the mass balance equation as follows: ( ) …(1) where c0 and ce are the initial and equilibrium concentrations of dye solution (mg/l), respectively; v the volume of dye solution (l); and w the mass of bamboo (g). the percentage of dye removal (%dr) was calculated as follows: ( ) ⁄ ...(2) 3.2. continuous system a fixed bed column used with 10 cm high and 2 cm inner diameter. bamboo was placed inside the fixed bed column at different bed depth (1, 2 and 4 cm) respectively then the column washed with distilled water to rid from impurities and air bubbles. the solution was pumped at different flow rate into the fixed bed column at different concentrations then the sample was measured by uv device before the experiment and at different intervals time as illustrated in figure 2. these experiments were carried out at room temp. 298k. fig. 2, experimental rig of continuous adsorption: 1-feed tank, 2-pump, 3-valve, 4flowmeter, 5-fixed bed column, 6-sample test, 7-drain results and discussion 1. batch system 1.1. effect of initial concentration and time the uptake of mg onto bamboo as a function of dye concentration is shown in figure 3. it can be seen that the amount of mg adsorbed per unit mass of adsorbent increased with increasing dye concentration, although percentage dye removal decreased with increase in initial dye concentration. this may be attributed to an increase in the driving force of the concentration gradient with the increase in the initial dye concentration [17]. as shown in figure 3, when the adsorption time increases, the adsorption capacity of bamboo increases significantly in the first 120 min due to rapid attachment of dye to the surface of the adsorbent, and keeps increasing gradually until the equilibrium is reached and remains constants [18]. the amount of adsorbed dyes did not show significant change after 140 min, these results are agree with gregorio crini [18]. fig. 3, effect of initial dye concentration and time on adsorption 1.2. adsorption isotherm isotherms studies have described the adsorption mechanisms, surface properties and the affinity of adsorbent towards adsorbate [19]. the 0.00 40.00 80.00 120.00 160.00 200.00 t(min) 0.00 20.00 40.00 60.00 80.00 % d r c=5 ppm c=15 ppm c=30 ppm adsorption of methyl green dye onto bamboo in batch and continuous system 68 ijcpe vol.15 no.1 (march 2014) -available online at: www.iasj.net distribution of adsorption molecule between the adsorbate (liquid phase) and the adsorbent (solid phase) is constant at equilibrium due to the amount of adsorbate being adsorbed is equal to the amount of adsorbate being desorbed from the adsorbent [20]. thus, it is important to fit the adsorption experimental data into an appropriate isotherm model. therefore, langmuir and freundlich isotherms were used to evaluate the relationship between the amount of dye adsorbed at equilibrium (adsorption capacity) and the concentrations of dye (5, 10, 15, 20, 25 and 30 ppm) at equilibrium state.as shown in figures 4, 5, 6. the langmuir isotherm is represented as follow: …(3) where q0 (mg/g) is the maximum amount of the dyes per unit weight of adsorbent to form a complete monolayer on the surface bound and kl (l/mg) is a constant related to the affinity of the binding sites [21]. the langmuir constants q0 and kl were determined from the slope and intercept of the plot and their values are listed in table 1. the freundlich expression is based on an exponential relationship and is generally applicable to a heterogeneous surface energy distribution. the equation is shown: …(4) where kf and 1/n are the freundlich constants related to adsorption capacity and adsorption intensity. the plot of log qe versus log ce gives straight lines with slope, 1/n and intercept, kf, respectively. from figures 5, 6 and table 1 it is observed that the experimental data of mg adsorption was followed by langmuir isotherm with correlation coefficient 0.984. the monolayer adsorption capacity for the adsorption of mg was found to be 20.41 mg/g. the value of 1/n was in between 0.1 and 1.0 confirmed the heterogeneity of the adsorbent, indicating that the bonding of mg and bamboo is strong [22]. table 1, regression parameters of adsorption isotherm r-squared constants model 0.984 qm=20.41 mg/g langmuir kl=0.213 l/mg 0.9004 kf=126.5 mg/g freundlich 1/n=0.84 fig. 4, adsorption isotherm of experimental data fig. 5, langmuir model of adsorption isotherm 0.00 4.00 8.00 12.00 16.00 ce(ppm) 0.00 4.00 8.00 12.00 16.00 q e (m g /g ) 0.00 4.00 8.00 12.00 16.00 ce(ppm) 0.20 0.40 0.60 0.80 1.00 c e /q e ahmed adnan atshan -available online at: www.iasj.net ijcpe vol.15 no.1 (march 2014) 69 fig. 6, freundlich model of adsorption isotherm 2. continuous system 2.1. effect of bed depth the adsorption of methyl green in the packed bed column is largely dependent on the bed depth, which is directly proportional to the quantity of bamboo in the column. the effect of bed depth was studied at concentration 10 ppm, flow rate 5ml/min and 298k. from figure 7 we noticed that when the bed depth increased the breakthrough time was increased. the mass transfer zone in a fixed bed travels from the entrance of the bed and progresses towards the exit.hence, for the same influent mg concentration and fixed bed conditions,an increase in the bed depth results in alonger distance for the mass transfer zone to reach the exit and therefore an increase in the breakthrough time [23]. these results are similar to tan [24] and min-yu [25]. fig. 7, effect of bed depth on breakthrough curve 2.2. effect of initial dye concentration the effect of initial dye concentration on the adsorption process with 10 and 20 ppm at a constant flow rate 5 ml/min and fixed bed depth 4cm is shown in figure 8. it can be deduced that, at a lower inlet concentrations, a slower breakthrough curve and the highest treated volume are obtained. the breakthrough point for 10 ppm and 20 ppm of mg inlet concentrations occurred after 60 min and 15 min respectively. the slow transport of dyes onto adsorbent due to the lower concentration gradient and resulted in a slower breakthrough curve [26], conversely, a higher concentration of mg has been shown lead to a higher driving force of mg to overcome the mass transfer resistance in the liquid phase. consequently, the time required to reach saturation decreased with increasing the inlet solute concentration. these results are similar to tan [24] and min-yu [25]. fig. 8, effect of initial concentration on breakthrough curve 2.3. effect of flow rate the effect of flow rate on adsorption was studied at different flow rate 5 and 10 ml/min at constant concentration 10ppm, bed depth 4cm. from figure 9 it is observed that at higher flow rate, the rate of reaching the breakthrough time is faster whereas in lower flow 1.00 10.00 100.00 log ce 1.00 10.00 100.00 lo g q e 0.00 100.00 200.00 300.00 t(min) 0.00 0.20 0.40 0.60 0.80 1.00 c /c i bed depth=1cm bed depth=2cm bed depth=4cm 0.00 100.00 200.00 300.00 t(min) 0.00 0.20 0.40 0.60 0.80 1.00 c /c i c=10ppm c=20ppm adsorption of methyl green dye onto bamboo in batch and continuous system 70 ijcpe vol.15 no.1 (march 2014) -available online at: www.iasj.net rate the rate of reaching the breakthrough time is slower. this is due to the residence time distribution of influent concentration to the adsorbent is greater in lower flow rate [27, 26]. fig. 9, effect of flow rate on breakthrough curve conclusions bamboo shows a good adsorbent for removal methyl green from waste water. in batch system the maximum percentage dye removal reached to79.4% and adsorption capacity was 15.5 mg/g. it's found that adsorption was highly dependent on initial dye concentration, contact time (the adsorption capacity increasing with increase concentration and contact time). adsorption isotherm was studied with langmuir and freundlich models. the experimental data was fitted well with lagmuir model (r 2 =0.984). for continuous system the breakthrough curve analysis reveals that the slower breakthrough time reached for lesser initial concentration, slower flow rate, and higher bed depth. nomenclature dr% =percentage dye removal mg=methyl green c0 = initial concentration of dye solution (mg/l) ce= equilibrium concentration of dye solution (mg/l) qt =amount of dye adsorbed on bamboo at time t (mg/g) qe= amount of dye adsorbed on bamboo at (mg/g) equilibrium c=effluent concentration at time t (mg/l) ci= initial concentration of dye solution (mg/l) references 1a.bennani karim, b.mounir, m.hachkar, and m.bakasse, a.yaacoubi, (2011), "adsorption of malachite green dye onto raw moroccan clay in batch and dynamic system", canadian journal on environmental, construction and civil engineering, no.2, vol.2, 5-13. 2o.tunay,water sci. technol. 34 (1996), 9-16. 3e.fotgacs, ctibor and o.gyula, environ. int. 30 (2004), 953-971. 4k.wu, y.xie, j.zhao and h.hidaka, j.mol.catal. a: chem.144 (1999), 77-84. 5e.kusvuran,o.gulnaz,s.irmak and o.m. atanur,h.i.yavuz, o.erbatur, j.hazard. mater. 109 (2004), 85-93. 6t.robinson, g.mcmullan and r.marchant, p.nigam,bioresour. technol.77 (2001), 247-255. 7muhammad aslam malan,sana ijaz and muhammad naeem ashiq, (2010), "removal of various dyes from aqueous media onto polymeric gels by adsorption process:their kinetics and thermodynamics, desalination 263, 249-257 8s. őzcan, b. erdem and a. őzcan, (2004), "adsorption of acid blue 193 from aqueous solutions onto nabentonite and dtma-bentonite", j. coll. interf. sci., 280, 44–54. 9l.t. teng, e. khor, t.k. tan, l.y. lim and s.c. tan, (2001), "concurrent production of chitin from shrimp shells and fugi." carbohydrase res., 332, 305–316. 10a. shukla, y.h. zhang, p. dubey, j.l. margrave and s.s. 0.00 100.00 200.00 300.00 t(min) 0.00 0.20 0.40 0.60 0.80 1.00 c /c i flow rate=5ml/min flow rate=10ml/min ahmed adnan atshan -available online at: www.iasj.net ijcpe vol.15 no.1 (march 2014) 71 shukla, (2002), "the role of sawdust in the removal of unwanted materials from water" j. haz. mat. b, 95, 137–152. 11s.j. allen, g. mckay and j.f. porter, (2004), "adsorption isotherm models for basic dye adsorption by peat in single and binary component systems", j. coll. internat. sci., 280, 322–333. 12z. aksu, (2005),"application of biosorption for the removal of organic pollutants": a review. proc. biochem., 40, 997–1026. 13c.namasivayam and sumithra, (2005), "removal of direct red 12b and methylene blue from water by adsorption onto fe (iii)/cr (iii) hydroxide,an industrial solid waste.j. environ.manage, 74, 207215. 14s. wang, y. boyjoo, a. choueib and z.h. zhu, (2005), " removal of dyes from aqueous solution using fly ash and red mud", water res., 39, 129–138. 15s. wang, z.h. zhu, a. coomes, f. haghseresht and g.q. lu, (2005)," the physical and surface chemical characteristics of activated carbons and the adsorption of methylene blue from wastewater". j. coll. interf. sci., 284, 440–446. 16tomalang, f.n., a.r. lopez, j.a. semara, r.f. casin, and z.b. espiloy. 1980. "properties and utilization of philippine erect bamboo". in international seminar on bamboo research in asia held in singapore, research center and the international union of forestry research organization, 266-275. 17hameed, b.h., d.k. mahmoud and a.l. ahmad, (2008), "sorption of basic dye from aqueous solution by pomelo (citrus grandis) peel in a batch system". colloid. surface. a, 316(1-3), 78-84 18gregorio crini,(2008), "kinetic and equilibrium studies on the removal of cationic dyes from aqueous solution by adsorption onto a cyclodextrin polymer" ,j dyes and pigments, 77, 415-426 19y.s., ho, c.t., huang, w.h., huang, (2002) "equilibrium sorption isotherm for metal ions on the tree fern", process biochemistry, 37, 1421-1430. 20g.o., el-sayed, (2011), "removal of methylene blue and crystal violet from aqueous solutions by palm kernel fiber", desalination, 272 (1-3), 225-232. 21c. k. lee, k. s. low, and p. y. gan. (1999), "removal of some organic dyes by acid-treated spent bleaching earth", environmental technology, vol. 20, 99-104, 22v.o., arief, k., trilestari, j., sunarso, n., indraswati, s., ismadji, (2008), "recent progress on biosorption of heavy metals from liquids using low cost biosorbent: characterization, biosorption parameters and mechanisms studies", clean, 36(12), 937-962. 23aik chong lua, qipeng, 2009“adsorption of phenol by oilpalm-shell activated carbons in a fixed bed”, chemical engineeringjournal 141, 3, 713– 718. 24tan i.a.w,ahmad a.l,hameed b.h."adsorption of basic dye using activated carbon prepared from oil palm shell:batch and fixed bed studies" 2008, desalination, 225, 13-28. 25min-yu teng, su-hsia lin."removal of methyle orange dye from water onto raw and acid activated montmorillonite in fixed bed", 2006, desalination, 201, 7181. 26s. sugashini and k. m. meera sheriffa begum, “optimization using central composite design (ccd) for the biosorption of cr (vi) ions by cross linked chitosan adsorption of methyl green dye onto bamboo in batch and continuous system 72 ijcpe vol.15 no.1 (march 2014) -available online at: www.iasj.net carbonized rice husk (ccacr),” clean technologies and environmental policy, in press. 27r. han, y. wang, w. yu, w. zou, j. shi, and h. liu, “biosorption of methylene blue from aqueous solution by rice husk in a fixed bed column” , 2007 journal of hazardous materials, 141, 3,713–718. iraqi journal of chemical and petroleum engineering vol.18 no.1 (march 2017) 121 128 issn: 1997-4884 effect of nanoparticles and surfactant on phase inversion of two phases nada m. farhan material engineering department, university of technology, iraq abstract in the present study, a pressure drop technique was used to identify the phase inversion point of oil-in-water to water-in-oil flows through a horizontal pipe and to study the effect of additives (nanoparticles, cationic surfactant and blend nanoparticles-surfactant) on the critical dispersed volume fraction (phase inversion point). the measurements were carried for mixture velocity ranges from 0.8 m/sec to 2.3 m/sec. the results showed that at low mixture velocity 0.8 and 1 m/sec there is no effect of additives and velocity on phase inversion point, while at high mixture velocities the phase inversion point for nanoparticles and blend (nanoparticles/surfactant) systems was delayed (postponed) to a higher value of the dispersed phase volume fraction (oil volume fraction) compared to the system of surfactant where the phase inversion point was occurred at low dispersion phase volume fraction. for all systems the desperation volume fraction at the point of inversion decreases with increasing mixture velocity. indeed, the results showed that surfactant was more effective on phase inversion point than solid nanoparticles. key words: phase inversion, surfactant, nanoparticles, oil-water flow, and pressure drop. introduction the flow of two immiscible liquids (oil-water) two phase flow through a horizontal pipe appears in many industries such as pharmaceuticals, food and especially in crude oil production. most of the flow pattern of two immiscible liquids (oil-water) has been observed are dispersed flow where one liquid can be the continuous phase and the other one is dispersed as drops in the continuous phase. the phenomenon of phase inversion occurs when the disperse phase volume fraction increased gradually until it becomes the continuous phase and the originally continuous phase becomes the disperse phase. the critical volume fraction of the dispersed phase where inversion occurs is known as the phase inversion point. predicting the phase inversion point has become very important for industries, in designing long distance of transport pipelines of crude oil and in the selection of operating university of baghdad college of engineering iraqi journal of chemical and petroleum engineering effect of nanoparticles and surfactant on phase inversion of two phases 122 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net conditions, pumps, downstream separation facilities. its impotence is due to the fact that at a phase inversion point there is a significant increase in the appearance viscosity of the oilwater mixture leading to increase in the pressure gradient. the effect of additives such as surfactants (interfacial tension) and solid nanoparticles on phase inversion carried out in batch processes and stirred vessels has been investigated for many years. selker and sleicher, [1] suggested that the type of dispersion cannot affected by interfacial tension; yeh et. al. [2] found that interfacial tension will cause inversion phase at equal volumes of the two liquids; clarke and sawistowski, [3] as well as norato and tsouris [4] concluded that the phase inversion is more difficult to occur at interfacial tension decreasing: binks and lumsdon [5] studied the effect of silica particle concentration, type of oil and oil-water ratio on phase inversion and emulsion stability. binks and whitby [6] found that the coalescence of droplets decreases as the particle concentration is increased, due to a decrease in the average drop diameter. binks et al. [7] found that water in oil emulsion stabilized by using hydrophobic particles and oil in water emulsions stabilized only by using hydrophilic particles in agitator vessel. varun malhotra [8] studied the effects of pure stabilizers (either silica nanoparticles or surfactant) and mixed stabilizers (combined silica nanoparticles and surfactant) on phase inversion of water in oil to oil in water in stirred vessels. a few investigators studied the effect of additives (nanoparticles, surfactant) on phase inversion of two phases (oilwater) flow through pipe such as salager et al., [9] who studied the phase inversion in the pipes, he found that the composition of the mixture at which the dispersion inverts is changing with surfactant; piela et al., [10] studied experimentally the influence of the additives of a surfactant and salt on the phase inversion point for water-oil flow through a horizontal pipe. the results showed that, the addition of a surfactant caused a little change in the phase inversion point, but the influence of salt was negligible; ngana et al., [11] studied the effect of reducing interfacial tension on the phase inversion process by adding a small amount of glycerol in the water phase flow during horizontal pipe. it was found that reducing the interfacial tension causes an increase in the oil volume fraction to complete the inversion process. many mechanisms are suggested for predicting the phase inversion, one of the most mechanisms used is the opposite processes of break-up and coalescence of drops (nienow et al., [12]). phase inversion occurs when the rate of coalescence for dispersed phase exceeds the rate of break up which leads to increasing in the effective viscosity of the mixture. (yeo et al., [13]; brauner and ullmann, [14]) concluded that phase inversion occurs at the point where the interfacial energy of oil in water dispersion equal to the interfacial energy of water in oil dispersion. another mechanism for explaining phase inversion occurs is a multiple dispersion when the small droplets of continuous phase trapped into the dispersed phase drops, which leads to increase the size of dispersed phase drops and becomes more capability to coalescence (groeneweg et al., [15] and bouchama et al., [16]) in this work the effect of additives (nanoparticles, surfactant and mixed surfactant-nanoparticles), on phase inversion point for two phase oil-water flow through a horizontal pipe is http://www.iasj.net/ nada m. farhan -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 123 investigated under several mixture velocities. experimental work the schematic diagram of the experimental setup is shown in figure 1. it consists of an acrylic horizontal pipe with an inner pipe diameter 12.7 mm (to get fully developed dispersion flow) and 6 m in length as a test section, pumps and pressure gauge. all experiments were conducted using two immiscible liquids tap water, which was used as an aqueous solution (density 998.2 kg/m3, viscosity at 1.002 cp and surface tension 72.75 mn/m) and kerosene (density 828 kg/m3, viscosity at 5.5 cp, surface tension 27.5 mn/m) at room temperature (25 o c) and atmospheric outlet pressure (1bar). the experiment started by pumping water and white oil from their respective storage tanks (tank 1 and 2) by means of pump 1 and 2 (see figure 1) into the test section via a t-junction, to ensure minimum mixing of the two liquids at the inlet point .the flow rates of liquids were measured using two flow meters just before entering the test section. after the test section the mixture flows into a separator tank to separate the oil and water by gravity. water and oil were led by pumps (3 and 4) from the bottom and middle of the separator tank in to the storage tank (tank 1 and 2). pressure drops were measured simultaneously for each experiment at six different locations over a distance of 1 m from the pipe inlet. the experimental tests had been conducted under different mixture velocities 0.8, 1, 1.9 and 2.3 m/s. the experiments started with the flow of water phase for few seconds through the horizontal pipe to ensure that the pipe wall was wetted by the water. after that, the dispersed oil fraction gradually increased by increasing the oil flow rate and decreasing water flow rate to keep the mixture velocity constant, this continued until inversion was observed and beyond up to single phase of oil flow. each experiment run was repeated three times to confirm the results. and the averaged results were reported here. in order to study the effect of additives on phase inversion, two types of additives were used titanium nanoparticles at 100 ppm (surface tension 61 mn/m), hexadecltrimethyl ammonium bromide (ctab) at 100 ppm (surface tension 39 mn/m) and blend of ctab/titanium nanoparticles at 200ppm (surface tension 48 mn/m). the physical properties of the titanium nanoparticles are tabulated in table 1. fig. 1: the schematic diagram http://www.iasj.net/ effect of nanoparticles and surfactant on phase inversion of two phases 124 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net table 1: physical properties of titanium nanoparticles titanium nanoparticles density (kg/m 3 ) 423 surface tension (mn/m) 61 average nanoparticle size 50 nm specific surface area 160 m 2 /g color white results and discussion 1. effect of solid nanoparicles figure 2 shows the pressure drop as a function of the oil fraction for a wide range of mixture velocities (0.8, 1, 1.9 and 2.3 m/s) with reynolds number ranged from 6903 to 22158. the results observed that at low mixture velocities 0.8 and 1 m/sec the influence of the solid nanoparticles on the phase inversion point is negligible. at high values of mixture velocity 1.9 and 2.3 m/sec the influence of the solid nanoparticles on the phase inversion point is significant. the phase inversion shifted forward (0.588 and 0.57 oil fraction) with respect to the inversion point for the case without any additives (0.45 and 0.43) respectively. (a) (b) (c) (d) fig. 2: effect of solid nanoparticles on phase inversion for different mixture velocity [(a) 0.8, (b) 1, (c) 1.9 and (d) 2.3] m/sec this can be explained by the nanoparticle physical properties and its type. it is well known that nanoparticles classified into two groups according to the hydrophobicity of particles; low hydrophobicity (hydrophilic nanoparticles) the nanopraticles are preferentially wetted 0.8 m/sec 0 0.5 1 1.5 2 2.5 3 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 oil volume fraction p r e s s u r e d r o p ( k p a ) without solid nanoparticles 1 m/sec 0 1 2 3 4 5 6 7 8 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 oil volume fraction p r e s s u r e d r o p ( k p a ) without solid nanoparticles 1.9 m/sec 0 2 4 6 8 10 12 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 oil volume fraction p r e s s u r e d r o p ( k p a ) without solid nanoparticles 2.3 m/sec 0 2 4 6 8 10 12 14 16 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 oil volume fraction p r e s s u r e d r o p ( k p a ) without solid nanoparticles http://www.iasj.net/ nada m. farhan -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 125 by the water phase (nanoparticles are initially dispersed in aqueous solution and preferred aqueous solution to be the continuous phase), and high hydrophobicity (hydrophobic nanoparticles) the nanoparticles are preferentially wetted by the oil phase (nanoparticles are initially dispersed in oil phase and preferred oil to be the continuous phase). titanium nanoparticle is one of the hydrophilic nanoparticle types. its addition leads to prefer water to be the continuous phase, thereby improving water wetting of particle surface which favors stability of oil dispersion phase in water continuous phase and reducing their potential of coalescence due to the decreasing in the average drop diameter. this required higher dispersed phase fraction (oil fraction) to occur inversion. 2. effect of surfactant the presence of surfactant can have a significant influence on the inversion process; they tend to favor one type of dispersion over the other. it is well known that surfactant posses an equal ratio between the polar and nonpolar portions. when placed in an oil-water system, the polar groups (hydrophilic head) are attached to water, while non polar groups (hydrophobic tail) are oriented to the oil. the mechanism of surfactant depends mainly on lowering the interfacial tension between two liquid oil and water phase. the interfacial tension is lowered due to the adsorption of surfactant molecules at the oil-water interface. indeed, some of them keep the drops of oil in water by charging their surfaces that reduce the physical contact between drops and allowing easier spreading of one liquid on the other. figure 3 shows that at low mixture velocities 0.8 and 1 m/sec the influence of the ctab surfactant on the phase inversion point is negligible but at high values of mixture velocity 1.9 and 2.3 m/sec the addition of ctab to the continuous phase (water) shows different behavior in which the phase inversion shifted downward (0.42 and 0.4 oil fraction) with respect to the inversion point for the case without the surfactant addition (0.45 and 0.43 oil fraction) respectively. this can be attributed to the physical nature of surfactent. if it is inonic (hydrophopic head), ctaionic (hydrophilic head) or non ionic type. ctab is one of the cationic surfactant types (highly hydrophobic surfactant), its positive charge allowed it to adsorb on the interface where it acts to lower the interfacial tension and to elicit marangoni stresses. this effect slows down the drainage of the continuous phase film between two opposing drops, which is an essential step to increase the coalescence of oil drops leading to decrease the volume fraction of dispersed phase will thus be needed to occur inversion. 3. effect of blend additives (solid nanoparticles-surfactant) the effect of blend additives (100 ppm titanium nanoparticles and 100 ppm ctab at total concentration 200 ppm) on phase inversion is shown in figure 4. the figure shows that the oil volume fraction at which inversion occurs nearly constant at low mixture velocities 0.8 and 1 m/s. at high mixture velocity 1.9 and 2.3 m/sec the inversion point occurred at (0.47 and 0.459 oil fraction) with respect to inversion point of the surfactant system (0.42 and 0.4 oil fraction) and inversion point of the nanopraticles system (0.588 and 0.57 oil fraction). this clearly demonstrates that the surfactant is much more effective than nanoparticles in phase inversion process. http://www.iasj.net/ effect of nanoparticles and surfactant on phase inversion of two phases 126 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net (a) (b) (c) (d) fig. 3: effect of surfactant on phase inversion for different mixture velocity [(a) 0.8, (b) 1, (c) 1.9 and (d) 2.3) m/sec (a) (b) (c) (d) fig. 4: effect of blend additives (solid nanoparticles + surfactant) mixture on phase inversion for different mixture velocity [(a) 0.8, (b) 1, (c) 1.9 and (d) 2.3] m/sec 0.8 m/sec 0 0.5 1 1.5 2 2.5 3 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 oil volume fraction p r e s s u r e d r o p ( k p a ) without surfactant 1 m/sec 0 1 2 3 4 5 6 7 8 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 oil volume fraction p r e s s u r e d r o p ( k p a ) without surfactant 1.9 m/sec 0 2 4 6 8 10 12 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 oil volume fraction p r e s s u r e d r o p ( k p a ) without surfactant 2.3 m/sec 0 2 4 6 8 10 12 14 16 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 oil volume fraction p r e s s u r e d r o p ( k p a ) without surfactant 0.8 m/sec 0 0.5 1 1.5 2 2.5 3 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 oil volume fraction p r e s s u r e d r o p ( k p a ) solid nanoparticles surfactant blend (nano+surfactant) 1 m/sec 0 1 2 3 4 5 6 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 oil volume fraction p r e s s u r e d r o p ( k p a ) solid nanoparticles surfactant blend (nano+surfactant) 1.9 m/sec 0 1 2 3 4 5 6 7 8 9 10 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 oil volume fraction p r e s s u r e d r o p ( k p a ) solid nanoparticles surfactant blend (nano+surfactant) 2.3 m/sec 0 2 4 6 8 10 12 14 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 oil volume fraction p re s s u re d ro p 9 k p a ) solid nanoparticles surfactant blend (nano+surfactant) http://www.iasj.net/ nada m. farhan -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 127 on the other hand, figures 2, 3 and 4 show that there is no influence of additives on phase inversion point at low mixture velocities (there is no changing in phase inversion point). at high mixture velocities 1.9 and 2.3 m/s, the oil fraction at which phase inversion occurred lowered to (0.45 and 0.43) than that without any additives, (0.42 and 0.4) for surfactant addition, (0.588 and 0.57) for titanium nanoparticles addition and (0.47 and 0.459) for mixing surfactant / nanoparticles addition. this can be attributed to the fact that the turbulence in pipe flow dominates the mixing between the two liquids leading to high interaction between them. indeed, figures 2-4 show that for all system the pressure drop increases with increasing mixture velocity. due to the strong interaction between oilwater two phase flow at high mixture velocities. also, this figures 2-4 show that the pressure drop increases at inversion point for all systems. this attribute to the increase in the effective viscosity of two liquids at this point. the peak in pressure drop became sharper and bigger with increasing mixture velocity for all systems, due to the growth of the effective viscosity increasing with the increase of mixture velocity; (ioannou et al., [17]; piela et al., [18]). conclusions the experiments observed that the presence of either surfactant or solid nanoparticles and (surfactant / nanoparticles) mixture have a significant influence on phase inversion point at high mixture velocities 1.9-2.3 m/sec, the dispersed oil volume fraction at inversion point (0.588-0.57) for nanoparticles and (0.47-0.459) (nanoparticles/surfactant) mixture systems are higher than (0.420.4) for surfactant system. in the (surfactant/nanoparticles) mixture the surfactant has a more effect on phase inversion point rather than solid nanoparticles. at low mixture velocity the phase inversion point was unaffected by increasing mixture velocity neither by additives. references 1. selker, a., sleicher, jr., c.a., 1965. factors affecting which phase will disperse when immiscible liquids are stirred together. can. j. chem. eng. 43 (6), 298–301. 2. yeh, g., haynie, f.h., jr. and moses, r.e., 1964, phase–volume relationship at the point of phase inversion in liquid dispersions. aiche j, 102: 260. 3. clarke, s.i., sawistowski, h., 1978. phase inversion of stirred liquid/liquid dispersions under mass transfer conditions. trans. icheme 56, 50–55. 4. norato, m.a., tsouris, c., tavlarides, l.l., 1998. phase inversion studies in liquid–liquid dispersions. can. j. chem. eng. 76, 486–494. 5. binks, b.p. and lumsdon, s.o., (2000a). catastrophic phase inversion of water-in-oil emulsions stabilized by hydrophobic silica. langmuir, 16, 2539-2547. 6. binks, b.p. and whitby, c.p., (2003). silica particle-stabilized emulsions of silicone oil and water: aspects of emulsification. langmuir, 20, 1130-1137. 7. binks, b.p., philip, j. and rodrigues, j.a., (2005). inversion of silica-stabilized emulsions induced by particle concentration. langmuir. 21, 3296-3302. 8. malhotra v., (2009). effects of mixed stabilizers (_anoparticles and surfactant) on phase inversion and stability of emulsions. m.sc. thesis, university of waterloo, ontario, canada. http://www.iasj.net/ effect of nanoparticles and surfactant on phase inversion of two phases 128 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net 9. salager, j.l., márquez, l., pèna, a.a., rondón, m., silva, f., tyrode, e., 2000. current phenomenological know-how and modeling of emulsion inversion. ind. eng. chem. res. 39, 2665– 2676. 10. piela, k., djojorahardjo, e., koper, g.j.m.,and ooms, g., 2009, influence of a surfactant or salt on phase inversion in a water–oil pipe flow. chemical engineering research and design, 8 7, 1466–1470. 11. ngan k. h., ioannou k., rhyne l. d., angeli p., 2011, effect of glycerol addition on phase inversion in horizontal dispersed oil–water pipe flows. experimental thermal and fluid science. 35, 628–635. 12. nienow, a., 2004. break-up, coalescence and catastrophic phase inversion in turbulent reactors. adv. colloid interface sci. 108, 95–103. 13. yeo, l.y., matar, o.k. and perez de ortiz, e.s., 2002, a simple predictive tool for modelling phase inversion in liquid–liquid. 14. brauner, n., ullmann, a., 2002. modelling of phase inversion phenomenon in two-phase pipe flows. int. j. multiphase flow 28, 1177–1204. 15. groeneweg, f., agterof, w., jaeger, p., janssen, j., wieringa, j., klahn, j., 1998. on the mechanism of the inversion of emulsions. trans icheme a 76. 16. bouchama, f., van aken, g., autin, a., koper, g., 2003. on the mechanism of catastrophic phase inversion in emulsions. colloids surf. a: physicochem. eng. aspects 231, 11–17. 17. ioannou, k., nydal, o.j., angeli, p., 2005, phase inversion in dispersed liquid-liquid flows, 29, 331-339. 18. piela, k., delfos, r., ooms, g., westerweel, j., oliemans, r.v.a., 2008, on the phase inversion process in an oil–water pipe flow. international journal of multiphase flow, 34, 665–677. http://www.iasj.net/ dr gayath _mag_.doc ijcpe vol.8 no.4 (december 2007) 19 iraqi journal of chemical and petroleum engineering vol.8 no.4 (december 2007) 19-24 issn: 1997 -4884 continuous de-emulsification of crude oil using packed column under various conditions g. a. r. rassoul chemical engineering department college of engineering university of baghdad iraq abstract this research dealt with desalting of east baghdad crude oil using pellets of either anionic, pvc, quartz, pe, pp or nonionic at different temperature ranging from 30 to 80 °c, ph from 6 to 8, time from 2 to 20 minutes, volume percent washing water from 5 to 25% and fluid velocity from 0.5 to 0.8 m/s under voltage from 2 to 6 kv and / or using additives such as alkyl benzene sulphonate or sodium stearate. the optimum conditions and materials were reported to remove most of water from east baghdad wet crude oil. keywords: de-salting, de-emulsification, crude oil, packed column . introduction crude oil consists mainly (by wt.) 84% carbon, 14% hydrogen, 1% sulfur and 1% nitrogen (1). corrosive materials such as sulfur and hydrogen sulphides were removed, because these can cause corrosion. the wet iraqi crude oil such as kirkuk main pay and zubair main pay in basarah have to separate salt water from crude oil before pumping it to export. different researchers (2-6) used different materials such as sulphonic acid with phenol to desalt water from crude oil. other additives such as sodium sulphate, mixture of 0.5% sodium sulphate with 0.5% phenol, starch, were also studied. during testing oil well production, after drilling has been complete, said removal, silt removal, and other debris removal are required to clean the well during initial well production. desalting and dewatering are necessary to remove undesirable components from wet crude oil. oil containing water during oil well production, when the production well near oil-water contact, or when there is water conning from the aquifer or when there is water injection in the aquifer. crude oil from different reservoirs has different amounts of asphaltenes, wax, bituminous which affect de-emulsification (4-6). unremoved most of the salt and water from the crude oil will cause corrosion and fouling when deposited on the heated surfaces (7-8). similarly refineries, separators, pipes, heat exchangers, etc will be subjected to corrosion during operation, if water in crude oil is not removed. dissolved metals act as catalyst during crude refinery. in order to remove salts and water, from crude oil, the crude oil washed with water and then demulsifier are use under electrostatic fields in order to break the emulsion (9-11). control ph by acid or alkaline is necessary in order to increase rate of de – emulsion. water cut increased during well life oil production, since water injection was used to increase the pressure in the reservoir. the interfacial tension between two immiscible or partially miscible liquids reflects in the ability of a particular surfactant systems to solubilize materials include ph and pressure (12 – 14). the solubility of a particular surfactant systems to solubilize materials which are hydrophilic -lipophilic in crude oil depends on ph, pressure, temperature. these long chain hydrocarbons (lipophilic) with hydrophilic radicals are similar to surfactants. using polymers as demulsifier will mix with those long chain hydrocarbons in crude oil making complex (10-12), since the polymer have wide range of different molecular weights. if the university of baghdad college of engineering iraqi journal of chemical and petroleum engineering continuous de-emulsification of crude oil using packed column under various conditions ijcpe vol.8 no.4 (december 2007) 20 surfactant was used well below the critical concentration of the surfactant without using the polymer, the surfactant will solubilize the long chain hydrocarbon (6-11). the east baghdad wet crude oil was studied because it gives stable emulsion with very active radicals. different behavior between polar radicals which exist in water and non – polar radicals which exist in crude oil resulting in forming different water layers around the oil drops (611). separation and migration depend on hydrophilic – lipophilic balance which can be represented by equation shown below which relates polarity and non polarity and the ph of the solution. the effect of changes in the hydrophobic chain length on the effectiveness of surface tension reduction is minimum (6-11). ∑ +−−−= 7)( )( ... 2 groupchpernumbersgroupm numbersgroupchydrophili blh if two oil drops are to coalesce and water of hydration must be displaced, the rate (rate 1) of oil coalescence will be expressed by       ∑−−= rt e crate ho θψ 2 1 24.0 exp1 if two water drops are to coalesce and separated by non-polar oil, the rate (rate 2) of water coalesce will be expressed by       − = rt m crate θ600 exp2 2 the hydrophilic groups contain mainly 70% of anionic groups such as carboxylic acid, alkyl aromatics sulphonic acid, alkane sulphonic acid, sulphuric acid. while cationic groups contain amine salt, quaternary ammonium compounds. the formation of small droplets requires that the system overcome both the adverse positive interfacial free energy between the two immiscible phases working toward drop coalescence and bulk properties of the dispersed phase such as viscosity (15 – 19). the possible sizes of the dispersed phase units range from the molecularly dispersed solution where "droplet" sizes are on the order of a few nanometers to macro emulsions with droplet diameters of hundreds or thousands of nanometers (8 – 11). experimental work the available properties of formation water is specific gravity= 1.12, viscosity= 0.65 cp, formation volume factor= 1.044 vol./vol., and compressibility factor= 2.077î 10-6 psi-1 (from iraqi national oil co., reservoir report (pvt analysis)). water salinity is around 2-3% which contains mainly cations of na, mg, ca, k, fe and anions of cl, hco3, co3, so4 *, (3). in the experiments, an artificial water had been formulated which consisted from 70% by vol. of 20 g/l nacl, 20% by vol. of 20 g/l mgcl2, and 20% by vol. of 20 g/l cacl2. used water content in crude oil was 5% by volume with salt concentration of 2% making total salt content in crude oil to be 1000ppm. fig. (1) illustrates the used electrostatic packed column which consists of about 10 liters vessel packed with packing materials and subjected to 3 kv dc, with continuous circulation of the wet crude blend oil. the packed column is connected to settler, pumps, control valves, and about 20 liters tank which contains stirred wet crude blend oil. initially the stability of emulsion was investigated by bottle test, using 20% volume containing 2% wt. nacl at different temperature, ph, mixing speed, % wash water, mixing time. variable electrical mixer was used for 20 minutes with speed 2000 rpm at 60°c. the studied demulsifer (concentration ranges from 0.4% up to 1.4% by wt.) was added to the mixture and shaken vigorously for about 7 minutes. then the mixture was left for different periods of time (ranges from 10 mins. up to 120 mins.) into the settling tank in order to separate water from oil. the studied surfactant concentratio n varies from 1 ppm to 8 ppm. east baghdad crude oil contains a high percentages of asphaltenes (about 6.2% by wt.) and it also contains metallic impurities such as 76ppm vanadium, 15 ppm iron, 30ppm nickel and has conductivity of 4.5 î 10-8 (o.m)-1. east baghdad crude has specific gravity= 0.9 and kinematic viscosity of 60 centistoks at 26.7°c additives were added to the crude oil in the mixing tank at constant temperature for certain period of time and then the mixture is pumped at specifie d rate into the packed tower at proposed temperature and time. then the mixture was left for different period of times ranging from 20 mins. up to 120 mins. into the settling tank to separate salt water from the oil. the studied parameters were packing of either ionic pellets, pvc pellets, quartz pellets, polyethylene pellets, non – ionic pellets at different temperatures from 30 °c up to 80 °c, at ph from 6 up to 9 for time from 2 to 20 minutes, and under voltage from about 2 – 6 kv using 2 ppm of either alkyl benzene sulphonate or 2 ppm of sodium stearate. this work was carried out in order to desalt water from east baghdad wet crude oil. using hydrophilic anions groups demulsifier in pvc packed bed. results and discussion different experiments were conducted in order to obtain the optimum variables to get higher water separation from east baghdad wet crude oil. the study was carried by keeping constant all variables and varying only one parameter, so that the optimum conditions was used to study the shortest time required for separation using packed bed. g. a. r. rassoul ijcpe vol.8 no.4 (december 2007) 21 packing gave a good separation at low retention time. therefore, these experiments were conducted at optimum previous experimental measurements. table (1) illustrates the experimental measurements of each variable, while, table (2) shows the studied parameter at constant other reported parameters. each figure has constant specified parameters except the parameters which have been plotted. figure (1) shows the percent water removal from wet crude oil versus retention time using 2 ppm of either alkyl benzene sulphonate or sodium stearate at constant other variables as shown in table (2). ph influences percent water removable at constant other variables and using 2 ppm of alkyl benzene sulphonate as shown in figure (2) and table (2). figure (3) illustrates the affects of voltage on percent water removal from wet east baghdad crude oil at constant other conditions. figure (4) and table (2) show the effects of temperature of crude on the percent water removal under specified conditions, while, figure (5) points the affects of using washing water on the percent water removal from wet crude oil at given conditions at shown in table (2). crude oil circulation velocity affects percent water removal as shown in figure (6) and table (2). different types of packing such as anionic, pvc, quartz, polyethylene (pe), polypropylene (pp), non ionic pellets all affects rate of water removal from east baghdad wet crude oil as shown in figure (7) and table (2). pvc pellets were easily available and gave good water separation and therefore, pvc pellets were used through all the experimental studies. the optimum findings of the studied variables at constant of other conditions were reported in table (3). percent water removal increas es steeply with retention time using 2ppm additives giving a high percent water removal within 15 minutes. similarly, ph of 7.2 gives a good percent water removal and then water removal decreases with ph. a higher voltage applied on the crude will give a h igh water removal from wet crude oil. pvc packing with 3 kv voltage applied is recommended to remove almost most of water from wet crude oil. the results indicate high temperature increases water removal up to 65°c, and after that higher temperature above 65°c will decrease water removal from wet crude oil. increasing volume of washing water will increase water removal from crude oil, while decreasing circulation crude oil velocity decreases water removal. the experimental results indicate ionic packing has tendency for high water removal as indicated by pvc which is better water removal than pp or pe which are non – ionic packing. separation depends on the interfacial phenomena between the packing, crude oil, salty water content, polarity, temperature, retention time and ph of the water phase. under current potential, the water layers segregate into lower phase leaving oil in the upper phase. phase separation depends on the structure configuration of the additives and their polarity. the packing increases the surface area between the two fluid phases which accelerate phase separation with efficiency. the studied parameters such as temperature increase active energy and hence increase the migrations and separations of water from the oil. hydrophilic anionic polar group in pvc will accelerate the separation of water from oil phase due to the chloride ions impeded in the pvc and under voltage will give rise to negative ion charges in the water molecules, even through there is low dc voltage and low % vol. washing water due to formation and rupture of tensio -active film (20-21). high viscosity of east baghdad crude oil will slow down water coalescence due to the high molecular weight of oil components. but having a high concentration of hydrophilic anionic polar groups will accelerate water coalescence. the existence of dissolved salts in water phase which is present in crude oil tends to form drops of water molecules dispersed in oil phase. the lipophilic hydrocarbon will dissolve in hydrocarbon oil phase and the hydrophilic radicals will dissolve in water phase, due to ionic polar radicals. the present of ionic polar radicals in the packed bed (such as pvc) will accelerate water separation from oil and hence water removal from oil. table (1) experimental measureme nts for each condition table (2) varying one operating condition while keeping other variable conditions constant continuous de-emulsification of crude oil using packed column under various conditions ijcpe vol.8 no.4 (december 2007) 22 table (3) the optimum studied conditions fig (1) electrostatic packed bed units figure (2) water removal versus retention time figure (3) water removal versus ph figure (4) water removal versus voltage figure (5) water removal versus temperature figure (6) water removal versus washing water volume percent g. a. r. rassoul ijcpe vol.8 no.4 (december 2007) 23 figure (7) water removal versus fluid velocity figure (7) water removal versus retention time conclusions the following points were obtained from experiments for desalting and dewatering of east baghdad wet crude oil: 1. 2 ppm alkyl benzene sulphonate removes almost 100% of salty water from the wet crude oil after 15 minutes. 2 ppm of sodium stearate removes salty water with slightly lower efficiency. 2. packing pellets indicate that anionic pellets and pvc pellets remove almost 100% of water from wet oil. 3. the best parameters used to obtain an efficient water removal from crude oil are, temperature of 65 °c, fluid velocity of 0.5 cm/s, ph of 7.2, 15% by volume washing water under 3 kv voltage for 15 minutes. nomenclature symbols meaning abs alkyl benzene sulphonate c1 collision factor for oil drops c2 collision factor for water drops cmc carboxymethyl cellulose cp centi poise eh free energy of displacement of hydrated layer at a "deep" surface hlb hydrophilic -lipophilic balance m number of – ch2– groups involved in adsorption pe poly ethylene pp poly propyle ne pvc poly vinyl chloride r gas constant 1.986 cal.mole -1.(c)-1 rate 1 rate of oil coalescence rate 2 rate of water coalescence s.s sodium stearate t temperature (°k) θ the fraction of the interface covered oψ electrostatic potential in interface relative to the adjacent conducting phase (mv) references 1. campbell, j.m. "gas conditioning and processing", 2nd ed., campbell petroleum series, usa, (1972). 2. al-jassim, a.s., "de-emulsification of different iraqi crude oil emulsions", m.sc. thesis, baghdad university, (1998). 3. hassan, h.a., slaiman, q.j.m., abu-al-gayd, a.k., "properties of petroleum and natural gas", iraq, (1985). 4. salager j.l., "the fundamental basis for the action of a chemical dehydrant: in fluence of the physical and chemical formulation on the stability of an emulsion", int. chem. eng., 30 (1), 103 – 106 (1990). 5. sanford, e., can. j. chem. eng., 62, 258 (1985). 6. davies j.t., "interfacial phenomena", 2nd ed., academic press (1963). 7. karine b.b. capabli a., lamesa, "polymer – surfactant interactions", phys. chem., 3, 2872 – 2878 (2001). 8. nordi k.g., sjöblom, j., and stenius, p., "water in crude oil emulsions: monolayer study of model polymer", coll. & surf., 63, 241–251 (1992). 9. menon v.b. wassan, d.t., "characterization of oil – water interfaces containing: finely divided solids with application to the coalescence of water in oil emulsion", coll. & surf., 29, 7–27 (1988). 10. "surfactants general information", clean rti. org., (2005). 11. adamson a.w., "physical chemistry of surfaces", 3rd ed., john wiley & sons (1976). 12. lemanceau b., adv. in coll. & int. sci., 20, 167 (1984). 13. "polymers wikipedia", eng. org., july (2005). 14. layman p.l., chem. eng. news, 62 (4), 17 (1984). 15. jersy k. stenius, p., sjöblom, j., nordi, k.g., "water in crude oil emulsions from norwegian continental", 63, 241 – 251 (1992). 16. "surfactant", creative developments limited (2005), www. creative developments co., june (2005). continuous de-emulsification of crude oil using packed column under various conditions ijcpe vol.8 no.4 (december 2007) 24 17. staiss f. bohm r., kupfer, r., "improved demulsifier chemistry", spe prod. eng., 334 – 338 (1991). 18. mitchell d. j., j. chem. soc. faraday trans., 77 (2), 601 (1981). 19. florence a.t., j. coll. int. sci., 79, 243 (1981). 20. kenneth, w.w., and gary w.s., "the roles chemical screening and electrostatic field selection in desalting" natco, (2003). 21. waterman, c., "operation and maintenance manual for desalter" petrolite co., (1982). iraqi journal of chemical and petroleum engineering vol.9 no.4 (december 2008) 7-12 issn: 1997-4884 the effect of tce addition on the performance of catalytic isomerization of n-hexane abdul halim a.k. mohammed, maha al-hassani and samar kareem chemical engineering department college of engineering university of baghdad – iraq abstract n-hexane conversion enhancement was studied by adding tce (trichloro-ethylene) on feed stream using 0.3%pt/hy zeolite catalyst. all experiments were achieved at atmospheric pressure and on a continuous laboratory unit with a fixed bed reactor at a temperature range 240-270◦c, lhsv 1-3h-1, h2/nc6 mole ratio 1-4. by adding 435 ppm of tce, 49.5 mole% conversion was achieved at lhsv 1h-1, temperature of 270ºc and h2/nc6 mole ratio of 4, while the conversion was 18.3 mol% on the same catalyst without adding tce at the same conditions. the activation energy decreased from 98.18 for pure pt/hy zeolite to 82.83 kj/mole by adding tce. beside enhancement the activity, selectivity and product distribution enhanced by providing dmb (dimethyl butane) which have higher octane number as compared with 0.3%pt/hy zeolite. indeed the increase of the 2.2-dmb/2,3dmb ratio with n-hexane conversion is more pronounced with tce than with pure pt/hy zeolite. introduction isomerization, cracking and alkylation are reactions that are catalyzed by acids. considering the enormous oil consumption in the modern world (over 3.5 billion tons in 2005), it can be stated that acid catalyzed reactions of hydrocarbon are major importance nowadays and not surprising numerous studies have been devoted to the subject. however, important questions with regarded to the mechanism and to the effect of the catalyst pore structure on the activity and selectivity remain to be answered [1]. regardless of reaction involved in the particular process it is very important that catalyst exhibits not only the capability to perform its specified functions initially but also perform them satisfactorily for prolonged period of time. the analytical terms employed in the art to measure how efficient a particular catalyst performs its intended functions in particular hydrocarbon conversion process are activity, selectivity and stability [2]. the most synthetic methods for zeolite modification are dealumination by means of steaming, leaching procedure and the modification with phosphorus compounds. generally it is assumed that the acidic properties of zeolite govern their activity, which explains why many studies have devoted to determination of nature, the number and the strength of acid site [3, 4]. lawrence tuckerkass [5] studied the isomerization of cyclopropane to propylene over alumina containing 0-6% fluorine. the catalytic test was carried out at 127°c. the maximum isomerization rate occurs at 1.2%f and is about 5000 times that found for fluorine free alumina. at higher fluorine content, the rate constant decreased moderately to a value which was about 30% that at the maximum. the activation energy decreased sharply from 29 kcal/mol for pure alumina to a minimum of 13 kcal/mole. it is gradually increased to 16-18 kcal/mole for higher fluorine content. fan van lin et al.[6] studied the isomerization of nhexane on both prepared and commercial pt/al2o3 as well as commercial pt-re/al2o3.they studied the effects of chlorinated hydrocarbon addition (methylene chloride, trichloroethylene (tce), chloroform and carbon tetrachloride) in the liquid feed on the activity. they concluded that chloroform show a most favourable chlorinating agent and they university of baghdad college of engineering iraqi journal of chemical and petroleum engineering the effect of tce addition on the performance of catalytic isomerization of n-hexane 8 ijcpe vol.9 no.4 (2008) indicate that upon chlorination the isomerization selectivity increased and the cyclization selectivity decreased. nattaporn et al. [7] studied the effect of various olefins addition (ethylene, propylene, 1-butylene and 1-pentene) on n-butane isomerization on sulfated zirconia (sz) at 100ºc. the addition of butene was able to lower average surface resistance to active intermediate. the improve isobutene formation rate caused by addition of olefin was due to an increase concentration of surface intermediate leading to isobutene. a problem that is encountered of in the isomerization of hydrocarbon is the rapid deactivation of isomerization catalyst that is because of the formation and accumulation of high molecular weight, carbon (coke) within the pore. in addition impurities presence in feed contributes to a rapid decrease in catalyst activity. another option to elevate the deactivation is to operate the isomerization process at high hydrogen to hydrocarbon and at relatively high temperature. however activity may be enhanced by adding the effective amount of such organic chloride compound such a perchloro-ethylene (pce) in isomerization feed stream. the concentration of organic chloride compound in the range of 0.01ppm to about 1000ppm gives an increase in activity and decrease in deactivation. one reaction mechanism that is believed to be occur in the process which helps to prevent the deactivation of catalyst is that the additive helps prevent high molecular weight hydrocarbons and impurities (such as sulfur compounds, olefins and aromatics) from adsorbing onto the catalyst surface at the reaction conditions of the isomerization process [6]. the objective of this work is to provide a method by which the activity of an isomerization can be enhanced during the use of acid catalysts in the isomerization of hydrocarbons. experimental work materials and catalyst n-hexane was supplied by bdh with 99% purity was used as feedstock for isomerization experiments. hyzeolite (cbv 600) powder was supplied from zeolyst international company was used as support for catalyst preparation. for preparing catalyst, 100 g of hy zeolite powder was mixed with 30% montmorillonite clay as a binder as suggested by murray [8]. the resulting were formulated and dried over night at 100ºc, then 0.3wt%pt/hy zeolite was prepared by impregnation method with a proper solution of hexachloroplatinic acid containing of 0.1590g of hexachloroplatinic acid and 8ml deionized water for 20gm catalyst. the impregnated extrudates were dried at 110ºc then calcinated at 300ºc for 3hr in a furnace with dry air. the calcinated catalyst was then reduced with hydrogen at 350ºc for 3 hr [9]. procedure and equipment the catalyst activity tests were carried out in a continuous fixed bed reaction unit. the reactor was a carbon steel tube with an outside diameter of 1.9 cm, 2 mm thick and 80 cm length. 30 cm3 of 0.3%pt/hy catalyst was charged between two layers of inert materials (glass balls). the catalytic reactions were carried out in the temperature range of 240-270ºc, lhsv of 1-3 h-1, h2/nc6 mole ratio of 1-4 and atmospheric pressure. the partial pressure of hydrogen was kept at 0.57 bar while n-hexane partial pressure varied between 0.139-0.419 bar. liquid products were trapped by condenser at -5ºc, collected periodically and analyzed by using gas chromatography. the gas chromatography model 438aa-vsa supplied by agilent technologies company was used for the analysis. this device equipped with column of 0.25mm diameter 100m length and fid detector. for catalyst activity enhancement, 435 ppm, the preferred additive of tce as noticed by maha alhassani [10] of trichloroethylene (chcl: ccl2) was mixed with the feedstock stream during the activity tests. results and discussion catalyst activity figures (1) to (4) show the change of n-hexane conversion and at different contact time (1/lhsv) and temperatures. as lhsv decreases n-hexane conversion increase. this means that increasing in the residence time, which leads to offer a plenty of contact time of feed stock with catalyst inside the reactor. all results indicate that low lhsv is favored for isomerization process, while with higher space velocities; conversions are lower, unless the temperature is raised. at 270◦c the conversion of nhexane increases from 5.91 to 18.3% by lhsv decreasing from 3.0 to 1.0h-1, respectively. these observations are well agree with the previous investigation reported by vu et al. [11] and exner et al. [12]. the increase of isomerization reaction temperature at constant lhsv increases the conversion of n-hexane. this may be due to increasing of the number of active sites that can be used for the reaction. abdul halim a.k. mohammed, maha al-hassani and samar kareem 9 the conversion of n-hexane on 0.3wt%pt/hy was enhanced from 18.3% to 49.5% after adding 435 tce and at 1 lhsv and 270ºc. the addition of tce in feed stream is leads to increasing the concentration of surface intermediate loading to iso-hexane and this leads to increasing the activity, one reaction mechanism that is believed to be occurring in the process which helps to prevent the deactivation at the catalyst is that high molecular weight hydrocarbon, carbon and/or coke react with free chloride present in the additive instead of forming and accumulating within the pores of catalyst, particularly at the reaction sites within the catalyst. another possible reaction mechanism is that the additive helps to prevent high molecular weight hydrocarbon such as aromatic and olefins from adsorbing onto the catalyst surface at the reaction condition of isomerizaton process. fig.1: a comparison between n-hexane conversion with and without using of 435ppm of tce over 0.3wt.%pt/hy-zeolite catalyst at various contact time and at 240ºc. fig.2: a comparison between n-hexane conversion with and without using of 435ppm of tce over 0.3wt.%pt/hy-zeolite catalyst at various contact time and at 250ºc. fig.3: a comparison between n-hexane conversion with and without using of 435ppm of tce over 0.3wt.%pt/hy-zeolite catalyst at various contact time and at 260ºc. fig.4: a comparison between n-hexane conversion with and without using of 435ppm of tce over 0.3wt.%pt/hy-zeolite catalyst at various contact time and at 270ºc. the conversion of n-hexane was assumed to obey irreversible first order kinetic equation with negligible deviation from plug flow [13]. plots of )1ln( 6nc x vs. 1/lhsv at different temperatures give straight lines with slops equal to rate constants as shown in figs. (5 and 6).the values of rate constant are tabulated in table (1). the effect of tce addition on the performance of catalytic isomerization of n-hexane 10 ijcpe vol.9 no.4 (2008) fig.5: first order kinetic model for n-hexane conversion over 0.3wt.%pt/hy-zeolite catalyst. fig.6: first order kinetic model for n-hexane conversion over 0.3wt.%pt/hy-zeolite (with 435ppm tce) catalyst. table 1 results of rate constant measurements nph2/nc6=4, temperature range (240-270)˚c). k, h -1 catalyst temperature, ºc 270 260 250 240 0.198 0.156 0.096 0.0569 pt/hy 0.667 0.397 0.290 0.222 pt/hy with adding tce the apparent activation energies for n-hexane conversion over 0.3wt.%pt/hy-zolite catalyst are calculated by using arrhenius equation, which satisfies the relation between rate constant and the reaction temperature.         rt e o a ekk (1) plots of [(lnk) vs 1/t] gives a straight lines with slops equal to the ( rt ea ) from which the activation energies were calculated. the results of the apparent activation energy estimated from fig. (7) are given in table (2). table 2 results of apparent activation energy measurements nph2/nc6=4, temperature range (240270˚c). fig.7: arrhenius plots for 0.3wt.%pt/hy-zeolite and 0.3wt.%pt/hy-zeolite (with 435ppm tce) catalysts. it was observed from data above that the activation energy of isomerization with adding 435 tce is lower than that without adding tce in hexane feed. the later catalyst related to the fact that the activity of 0.3wt%pt/hy with adding tce is higher than without adding and that the addition of tce in feed stream. the addition of tce in feed stream increases the number of the isomerization active sites and decrease the olefin content which leds to side reactions such as cracking. also the addition of tce in a feed stream serves to improve the selectivity to the desired product and aging properties of catalytic system. these observations are agreed well with the results reported by jan-ku et al. [14]. the main products of isomerization of n-hexane are 2 methyl pentane (2-mp), 3 methyl pentane (3-mp) ,2,2 dimethyl butane (2,2-dmb) and 2,3 dimethyl butane (2,3-dmb) for example only methyl pentane which has octane number 75 are formed from hexane when sample ea, app (kj/mol) pt/hy 98.18 pt/hy with adding tce 82.88 abdul halim a.k. mohammed, maha al-hassani and samar kareem 11 0.3 pt/hy zeolite was charged while 2,2 dmb and 2,3 dmb which have octane number 95 were formed with adding 435 tce to feed stream. figures (8) and (9) show the influence of temperature between 240-270˚c on the isomerization selectivity and the product distribution. only isomers formed at low conversion and a small amount of (c1-c4) products (<0.5%). the isomerization selectivity slightly increased with increasing temperature. the total isomerization selectivity was about (≥97%) over the pt loaded catalyst. the relation between the 2,2dmb/2,3dmb and 2mp/3mp ratios and conversion is shown in figs. 10 and 11 respectively. the ratio of 2.2dm/2.3dm on 0.3wt.%pt/hy is very small while the ratio is higher where 0.3wt.%pt/hy by adding tce. since, the branching is the limiting step of the bifunctional mechanism. with this mechanism 2mp and 3mp should be formed at a similar rate which can be observed, at low conversion however, the thermodynamics equilibrium between 2mp and 3mp is rapidly established because of their rapid isomerization through a methyl shift. indeed the formation of 2,3dmb requires two successive branching pcp on the acid sites (equation 1 and 2). since this branching is the limiting step of the bifunctional mechanism the formation of 2,3dmb should be consecutive to that of mp. indeed methyl shift (a isomerization) is now to be faster than isomerization through pcp (b isomerization). further more 2,3dmb should be formed more rapidly than 2,2dmb since 2,3dmb formation involves tertiary cation. these observations are in agreement with the results reported by allain et al. (15) and martens et al. (16). (1) (2) fig.8: isomerization selectivity as a function of conversion for 0.3wt.%pt/hy-zeolite fig.9: isomerization selectivity as a function of conversion for 0.3wt.%pt/hy-zeolite (with 435ppm tce) catalyst. fig.10: products distribution as a function of conversion for 0.3wt.%pt/hy-zeolite and 0.3wt.%pt/hy -zeolite (with 435ppm tce)catalysts. the effect of tce addition on the performance of catalytic isomerization of n-hexane 12 ijcpe vol.9 no.4 (2008) fig.11: products of distribution as a function of conversion for 0.3wt.%pt/hy-zeolite and 0.3wt.%pt/hy -zeolite (with 435ppm tce) catalysts conclusions 1) n-hexane conversion increases as the temperature is increasing from 240 to 270°c and decreases as the lhsv is increasing from 1 to 3 h-1. the highest nhexane conversion 49.5 mol.% was achieved over 0.3 wt% pt/hy zeolite catalyst with adding 435 ppm on feed stream at lhsv of 1 h-1, temperature of 270°c and h2/nc6 =4 mol ratio. 2) it was observed that the values of activation energy for hydroisomerization of n-hexane over the prepared catalysts take the following order: 3) eact of 0.3wt% pt/hy with adding tce < eact of 0.3wt% pt/hy. 4) all the catalysts gave a high selectivity, and no significant change in the total isomerization selectivity was observed, while the product distribution is a decisive factor for catalyst activity evaluation. by adding tce in a feed stream enhanced the selectivity toward 2,2mb and 2,3mb (higher octane number). reference 1) gauw f.j.m., grandell j., santen r.a., 2002,"the intrinsic kinetics of n-hexane isomerization catalyzed by pt loaded solid acid catalyst", j. catal. 206, 295-304. 2) hilfman lee, 1979, "hydroprocessing of hydrocarbons over nickel, molybdenum, and platinum catalyst", us patent, 4175033. 3) bokhoven j.a., tramp m., koningsbarger j.t., miller and pieters j.a.z., lercher j.a., williams, kung, 2001,"an explanation for enhanced activity for light alkane conversion in mildy steam dealuminated mordenite", j. catal. 202, 129-140 . 4) rabo j.a. and gajda, 1989, "development of kinetic model of reforming reaction on zeolite", j. catal. kev. sci. eng., 31, 385 5) lawrence tucker kass, 1998 "isomerization process with improved chloride recovery", united states patent 5705730. 6) fan van lin, edger d., davids, 2000, "isomerization of n-hexane", us patent, 6140547. 7) nattaparn, lohitharn and james g. goodwin, 2007,"n-butane isomerization on sz", j. catal. 245 198-204. 8) murray brendan, 1997, "isomerizing linear olefins to iso-olefins", us patent, 5648584. 9) ribeiro f., marcilly c., and guisnet, 1982,"hydromerization of n-hexane on pt zeolite", j. catal. 78, 267274. 10) maha al-hassani 2007,"kinetic study of n-hexane isomerization", m.sc. thesis, baghdad university. 11) vu t.n., gastel j.v., gilson j.p., collet g., dath j.p., and duchet, j.c., 2005, "platinum tungstated zirconia isomerization catalysis part ii effect of pt on the mechanism of isomerization of n-hexane" j. catal. 231, 468-479. 12) exner h., nagy e., fetting f., gubicza l., 1989,"kinetic of hydroisomerization of n-alkane on nickel zeolite", proc. of 5th conference of applied chemistry unit operation process, vol.2, 420-425. 13) fujula f., lembert m., figueras f., 1989, "studies in surface science and catalyst", vol. 62, pp.150. 14) jan-ku, chen, a.m. martin, young gull kim and vijay t. john, 1988, "mechanical study of isomerization of n-hexane", ind. eng. 27, 401-409. 15) allain p., nagnoux schulz ph., guisnet m., 1997, "hydroisomerization of n-hexane over platinum mazzite and platinum mordenite catalyst kinetic and mechanism", appl. catal. a: general 52, 227. 16) nagy e., felling f. and halsig, g.p.,1984, "an assay of mass transport and kinetics of isomerization of n-hexane", acta chemical hungarica, 115, 4, 383-395 . rfcptl r a q i j o u r n a l o f c h e m i c a l a n d p e t r o l e u m e n g i n e e r i n gv o l . 8 n o . 1 ( f t 4 a r c h 2 0 0 7 ) 4 7 5 0 corrosion inhibition of low carbon steel in different hci concentrations by phenythiourea a p r a e l s , y a r o ' , n a s h w a n a . r a s h e d ' ^ , a n d a h m e d s . a b d u l h a s s : r n ^ ' c h t q i c o t l a g . n e " l : u d . p a n . ! . a t t , g . u j l a s t a , $ i , g t n i v ' r s . ^ o j b n s | / " j h . t l c h ? " t i c a t s t h l p , c e n e t i t i a r t t a l h a l 5 y a r j u ' t . ' i l , r l abstract phentlthio tea (phtu),'|as te\ted as inhibitar for the carasion af la\r carban stlcl ,t dilletent hci dcid canccntration bf nast loss,and palari:ation neasuretrents .it \|as faund that (phtu) i! d gao!1 inhibitar fat ttrc canosion af loh, carbon steel in l,3,and 5n hci satutian ,ahd tu inhibitian e[iciency (0) incrcsscs \9ith its cancentrction and a oins dpproindtely 97% at lg/l .polatization curws indicate that (phtu) dcts ds an dno.lic i,pe inhibilor the irhibitot wos atlsorbed on the |ae carban steel slltlace according to the langnrir adsotpti.)n isatherm nodel. results shov, thdt the rcte af camsion aflaw catbotl steel in.reased rrith incrcd!lng tentwtutu e orer tte trtlse 30-64'c, both in the presence af inhibitat and its absence .it uasfound atsa that the hrhibitikg qfect afllc inhibitot is genetuur acid concentration independent. /(sjralr/s: phenylthiourea, lowcarbon steel, corrosion inhibition. introduction to control the corrosion ofmelals in several industrial processes, acjd inhjbitors are usually used. m€tals are exposed to lhe action of acids i! many ways, and for many diff€rent reasons. the exposures can be most severe bu! in many cases, the corrosion can be controlled by nicass of inhibitors. processes jn lvhich acids play a very impo11ant part arer acids pickling, industrial acid c l e a n i n g a n d o i l w e l l a c i d i z i n g l l . m o s t o f r h e w e l l known acid inhibitors are organic compounds containing nitrogen (n), such as amine and hetrocyclic compounds, besides sulphur and oxygen. the influence of fiese organic inhibitors on the c o r r o s i o n o f s l e e l i n a c i d i c s o l u t ; o n s r a s o c € n investigated by several workers [2-4].the existing data show, that most organic inhibitor used, act by adsorption o n l h e n r e t a l s u f a c e . d i e s e l e c t i o n o f a s u i t a b l e i n h i b i t o r fbr a ce(ain process depends on many faciors; such as: iis chemical structural, its concentraiion, the naru.e of metal used and $e type ofacid used. the ainl of this study is to investigate the fol€ played b ) p h e n ) h f i o l r c a a s c o u o s i o n i r h i b l o r o n r h e c o r r o . i o n i n h i b i t i o n o f l o l v c a r b o n s t e e l i n l , 3 , a n d 5 n h c i a c i d experimental work gravlmetric measurements the experiments were carried oui in solutions of u n i n h i b i t e d 1 , 3 , & 5 n h c i a c i d s o l u t i o n o n l o w c a r o o n s t e e l c o n t a i n i n g 0 . 0 4 1 % c , 0 . 3 % m g , 0 . 0 5 % phosphorus,o.007% s, remaindep/o iron. specimens jn $ e f o r m c o u p o n s w i t h d i d r e n s i o n s o f ( 7 8 9 x 1 . 5 ) c m 2 a n d a thickness of 0.09 cm were used for mass loss measurements studies. they were poiished wilh emery p a p e r o f g m d n u m b € r s 2 2 0 , 3 2 0 , 4 0 0 a n d 6 0 0 . c a c h r u n w a s c a r r i e d o u t i n a g l a s s v e s s e l c o n t a i n i n g l 0 0 0 c m r t e s t s o l u ' i o n . a c l e r n $ e i 8 h e d l o $ c j r b o i y e e l s p c c i 1 ' c l u . . c o n r p l e t c l y i m m e r s e d i n i , 3 , & 5 n h c l a c i d a t 3 0 , 4 0 , 5 0 , & 6 0 ' c . a f t e r 2 h o u r s o f i m m e r s i o n i n 1 , 3 , & 5 n u n i n h i b i t e d l l c l a c i d , t h e s p € c i m e n w a s d r a w n . r i n s e d i j c p e v o l . b n o . 1 ( l \ r l a r c h 2 0 0 7 ) 4 7 ca asian inhibitian low carbon steel in ent hci cancentratians by phe vlthiourca with distilled water, washed wilh ethanol& acetone' dficd& weishted. the mass loss was used to calclrlate ihe corrosion rate in sranls per meter square per dav (gmd)' polarization measurements cylindrical electrode (l 96cm outside dianreter and widih of 0.5cm) = 3.13 cm'? area was prepared from investigated carbon sleel. sanrples were abraded in t . n " i . " . a . t r u n r i n g r " p w l e r l r s i n g e m e r y p a p c r o f c r r a n u r n l , c r . 2 ? 0 , 3 2 0 , a 0 0 , n d 6 0 0 l h c n $ a s ' r e d $ i l l r ilrnning tap water followed by distilled water, dried with clcon thsue. innrersed in acetone and benzene, kept nr a d e e i c a l o r o v e r s i l i c i g e l b e d l r n l i l u s e t h e c o n c e n t r a , i o n r a n g e o f i n h i b i r o r u s e d w r " ( 0 l 0 . ? 5 . c n d i g l ) . 1 h e s l l | a i . s * " t c c . r r i e d o u t p o l e n l i o d r n a n i c a l r y i i n a r h e r m o s r a l e d e l e c l r i c a l l i c c e l l p l a r i n ' r m t l i t * u , " s . a u " a . o r n t . r _ e l e c r r o d c l c e r r n d a s a l j r a l e d calomel electrode as a refercnce electrode (sce) the laler was connected through a luggins capillary to the cell. the wolking eleclrode (we) was immersed in a test solution .the potentiodynamic current_potentlal curves were recorded by changing dle electrodc polenllal m i l u . l h l r o m ' 8 0 0 l o 1 0 0 r v r s c l r ' a l l e \ p e r i r e n s u c r c c a i r i c . t o r r i 1 l l e . h l ) p r e p r r c d s o l , r t r o n : n ( o n r l a l l temperanrrcs 130,40, 50r and 60oc. results and discussion l/ass loss measurements table i collects the vahles of corrosion rate obtalneo from nlass loss measurements for diffelen! temperalures in diffefent hci acid concentrations. table i sbows that corrosion rate of carbon steel is firnction of both the lemderatufe &acid concentratior .this nreans tha! fol ( c r l d i r l l e l n p c l r r l r e o l a l i d l o n c e n l r d t l o n l o _ o s i o n r a l e i r r e . b e s d s i h e c . i d c o n c e n l r r l i o l o r l e n p e r d t u r c increases respecilvely. to elucidate or deiermine the activation energies ofthe coffosion pfocess, nass ]oss measuements *ere prefomed al various temperatures ill the at'sence 0r i r i b i t o r u s e d . i i l a ' b e e n i e p o r l . d ( l . r ' f o r i r o n & s l e e l i n s c i d l l ) e l o : d r i r h m o f i ' c c o r r o ' i o n r j c o f s l e c l c r c a n b e ieiresentea as a straight line funclion of(l/t) (arrhenius f t ^ o c r = l a b ( l ) 2 . ] r t where e is the activation energy, r, is the unjversal sas constan! and b is a constant the variation in i " " r . i , n l n " r . " * i " " ' " r e o r c . r r b o n s r e e l i n l l a n d 5 n h i l a c i d ' o l u r ' o n . ; r t h e a l ' s e n c c o l ' n h i b i r o r ' \ i r r i""lp-*t oi tt e absolute temperature! is given in figr rt" "utculut"a value of (e), shows that incrcas;ng of acid concentration fron in to 5 n was associated wilh a decrease in activation energy ftom 16 to 12 5 kcal/mol r e s p e c t i v e l y t h r o u g h 1 3 7 k c a l / n r o l i n 3 n h c i a c i d several values given in lhe liierature for activation enersv of carbon steel in hci solutions, ranging fronr l l 8 ] o 2 1 . 0 k c d l r n o l i s l , $ i r h m a j o r i r ) s r o u p e d a : ? \ l t ' 1 4 . 5 k c a l / m o l e . y a r o t 6 l o b t a i n e d a v a l u e o f : : ] kcal/mole fo[ the corosion of carbon sleel in i\ :i: acid soluiion. electrochemical measurements potentiodwamic anodic and cathodic po::-_=' s c a n s w e r e ; a r r i e d o u t a t 3 0 , 4 0 , 5 0 , a n d 6 0 ' c : and 5n hci with different concentraliods of i: anodic and cathodic polarization cllrves in abss':: i n r h c p e s e n c e o f i n \ i b i l o r n t d i f f e r e n l c o n . e e o a f t e r i m m e r , i o n i n i , l , d n d 5 n h c i a c i d ( ' t 3 0 " c a r e 5 r o $ n i n f i 8 2 ' d a s a l r n p l e ' _ : n t dolarizalion !unes rl 40, 50 ard 60'c 'l diiterti:' l . . inhibitor concentralion immersed in 1, 3, and 5 n are not sholvn here, but they were used to find coroslon parameters i."", r", and rc) l! can be seen from figures 2-4, thai in the prcsence ol r n h i b i l o r . r h c ( u r \ e " a r e , h i f t e d t o l o q e r c r r r e . ] l r e g i o s showina the inhibition tendencv of (phtu) the values of varlus electrochemical co osion parameters are summarized in table 2. the e."" values were generally shifted pronounsly in the pres;;e of inhibilor to the posilive direction' these obs;rvations show clearly that the inhibition ofcorrosion is under anodic control (i.e, polarization occur's on the a n o d i c & t h e e " , s h i f i e d t o t h e o p e n c i r c r ' r i l o f t h e cathode) i7l. rhc coriosion cuffent densitics and tafcl slopcs wefc estimated by betacrunch program developed .by g r e e n a r d c a n d i [ 8 ] o n l h e a s " u n p l i o . 1 r l a l h c c o r f o ' r 0 n r e a c r o n i q t o m p l e r e l y u r d e r a c t : v j l i o n c o n l r o l a n d i ' r o t complicated with ir drop or mass transfer' lnhibition "ir,"i"n"y *ut then calculaled using the mathematical a _ l i t c a r n n i " \' h.,u, ) (2) where i."" (ln) and l.""(un) are the corrosive current wilh and without inhibitor receptively table 2 sbows that an increase in inhibition in inhibitor concentration is resulted in increased inhibition emciency, i! is evident from the results that th€ i*" values considerably decreased in the presence ofinhibitor and that the maximum decrease in ic"" coincides with the maximum concentration of inhibitor [9] the inhibiior s r u d i e d p e r r o r m e d e \ l e l l e l r l v ( 9 0 5 ' o i n h i b ; r i o n e f f i ( i e n l y " l l g u a q i n h i b i l o r o l l h e c o ' r o s i ^ n o f l o w carbon steel in ln hci 4 8 ijcpe vol.b no.1 (l\,'larch 2007) : h a . 2 6 {cl , 3 , i.j), l a l rhe i o n i o n t h e t h e by i o n t h e i o n ' ( 2 ) surfac€ coverage (g) values have been evaluated for different concertration of (phtu) under study from corrosion rates in uninhibned and inhibited solutions using eq. 2. the langmuir adsorption isotherm €xpressed kc ':i: cu.dnot : .' . i ! u 1 + k c c t ^ e k tchp.tohtre,"c 30'c:5n hci 9 n i l 7 i 7 . l l l 0 0 l g i n h . t 2 5 0 t i i 0.75ginh 84.22 1 2 l g i n h . 7 0 6 9 4 0 ' c r l n h c i t 3 n i l 1 0 1 3 . 8 9 1 4 0 . l c i n h , 6 5 . 9 8 1 5 0 . 7 5 e i n h . 5 0 . 1 9 1 6 l g i r h 4 2 . 9 3 4ooc:3ntlcl 1 7 n i t 1 2 1 1 . 3 3 1 8 0 . l g i o h 1 1 1 : 1 4 1 9 0 7 5 e i n h 8 5 6 5 2 0 i i i n h 6 1 0 3 40'c:5n tlcl 2 t n i l 3 1 7 8 . 3 6 22 0.lg ioh, 399,23 2 3 0 7 5 g i n h . 2 8 9 9 24 lginh 229.39 5 0 0 c r n u c l 2 5 n i t 1 6 0 1 , 0 7 2 6 o . l g n n r 1 1 1 7 1 2 7 0 7 j g i r . 6 4 8 4 2 8 l g i r h . 5 8 . 1 7 50'c:3n flcl 2 9 n i t 6 1 9 9 . 2 8 3 0 0 . l g i n h , 9 0 3 . 8 9 3 l 0 . 7 5 9 i n f i . 5 7 6 1 5 32 ig inh. 319 50'c:5n ilcl n i l 0 . 1 9 i n | . 0.7ts i,rh l g i n h . j t i 3 . 1 1 t ! r i : : t 2 : 5 : i _ _ s i r ! { 0 5 l 1 i _ t ! ! ! _ 1 2 . 1 . 1 4 i 5 t t : : : 5 3 . 0 8 5 4 | l n i l 4 7 . 1 7 6 t 7 t 9 3 6 l 7 3 . 6 8 8 3 . 6 7 9 5 . 1 4 44.28 52.51 94.84 7 0 9 5 7 1 . 5 5 n i t 3 9 . 1 4 4 3 0 4 9 0 8 40.82 41 t9 929 48.73 56.89 94.4 7 0 . 9 5 7 1 5 5 n i t t 0 l 4 ? i i 8 . 8 3 8 7 4 3 88.74 99.08 90 87 85.9 92.6 92.78 46.14 41.54 nil 43.57 4928 93 n2 4 1 . 1 4 4 9 . 1 6 9 5 t 6 4822 56.16 96.32 95.91 97.99 nil 46.16 4847 85.41 46.49 54.92 90 7 43.64 46.32 93.88 l 0 , l 6 7 1 0 5 8 9 n i l 5 2 2 1 5 2 1 1 7 9 7 4 8 . ? t 5 3 9 5 8 4 2 4 9 . 6 2 5 1 . 8 5 8 8 . 1 6 where k is the equilibdum consiant for the adsorption isoth€rm process, c ;s the inhibiror concentration (91) a n d e i . r h e s | . f f a c e c o ! e r a g e . r e d r r a n g i n g e q j : (4) it was found dut fig. 5 (plots of c/6 vs. c) for phenylthiourea inhibitor gives srraight iines with slope, praclically equal to unity, indicatidg rhar the adsorption ofphtu undef consideration on carbon steel in t, 3, and 5 n i l c l a c i d s o l u r i o n s i n r e f a c e o b e ) . t . , n g f l u r s adsorption isorherm. lt is important to mention here that the same behavior was obtained at 40, 50, and 60.c. the deviation of 1he slope fiom unity is artributed to the difference in tbe rate of interaction betwecn tbe adsorbed species on d1e metal surface. from the intercept ofthe straisht lines on the c/0 axis, k vahres were calculared. table 3 shows the eqlrilibrium constant ibr langmuif lype adsorption ofphfu inhibito. in 1n hcl acid solution at different tenrperature table i effect oftemperature and hci acid concentration on lbe corosion rate (g/m'zday) ofcarbon steel 40"cl 0 . c 50"c i n 3 n 5n 3 9 . 3 5 6 0 2 . 5 5 4 5 6 . 1 7 1 9 0 5 . 4 6 3990.249 9 9 8 7 . r 7 2i22,95 t 5 7 6 . 4 r | l 8 2 4 2 t 5 1 . 8 2 2 7 9 . 8 1 t 7 7 . 8 2 7 4 t . 3 1 t3t8.25 2454.11 l l 34 3 5 36 j 7 3 8 l 9 4 0 table 2 conosion current density, ba, 0c and efl values obtained for low carbon steel in differenr acro concentrations in absence &presence ofphtu 6 0 ' c : 1 n f l c l nit 2594.68 0 . l g i n n . 1 9 9 . 1 5 0.759inh. 109.24 i g i n h . 9 2 3 52 62 53.05 63.83 74 64 3 3 . 4 t 3 4 0 9 43.01 49.69 n i l 92 31 9 5 7 8a;: c,,,r,,a, ,.|;,, .f,u ,,f1" trji % lo,c ln flcl i n i l 2 0 l g i n n . 3 07tg inh. 4 r 8 i n h . 30.cr3n hci 5 n i l 6 0 lg infi. 7 0 7 5 9 i n h . 8 l g i n h . 60'c:3n hci , 1 1 n i t t 9 9 6 5 l 4 2 0 l c i n h . 1 0 8 8 . 5 8 4 3 0 7 5 g i o h , 8 7 6 . 0 4 44 lc inh. 527 600c 5n hci 4 l n i t t 0 4 5 4 . 9 8 , 1 2 0 . l g i n h 1 8 4 0 . 7 1 ,11 0 75bnrh. 1622.14 4 4 l g i n h 1 3 5 4 . 1 5 6 7 5 1 6 9 . 1 1 n i l 3 5 | i 3 t . . 1 3 8 1 . 8 4 4 6 4 3 5 r . 6 1 8 5 l 9 t 8 . t 8 4 2 , 9 2 9 t 2 t 7 8 . s 7 7 9 1 3 n i l 4 7 . 5 8 , 1 8 . r 7 7 7 . 4 8 61 78 71.81 82.j9 4 8 . 1 9 4 9 t ? 8 , 1 4 8 i t 5 . 7 1 2 r . l 9 t 7 . 2 2 t 4 . 9 3 6 4 r . 8 9 9 1 5 5 5 t . 4 6 n i l 93.2 94,54 95 21 n i l 85.73 9 t 9 8 9 2 1 5 5 5 . 7 3 6 1 9 l 4 0 8 3 5 0 8 5 44 94 53.29 46.91 65.56 4 9 . 2 5 7 8 4 7 6 6 5 1 . 2 5 50 82 34.02 42.47 46.62 u c p e v o l . b n o . 1 ( m a r c h 2 0 0 7 ) 4 9 carras io)1 i nhibit iott af lo|| cafto" steet i' differcnt hclconcentt dttans ' i a b l e i e q u i l i b r i u m c o n s l a n t l o r a d s o r y l i o n o f t h e p h t u i n h i b i l o r sollrtion at difierenl temperatures langmuir type i n l n t l c l a c r d 3 0 4 0 5 0 6 0 2 9 8 3 , 0 4 3 1 0 3 1 6 j 2 2 ( 1 / t ) x l o " k " i r r . i a r r h c n l u s p o l l o l l o j c o l o ' l o n r " t e s r d r r o ) v s ' . . i p * , ̂ i " i " r , * 1 " " " " l i t d ' r f e r c n l l l c l r ( i d c o r r c fig.4 polarizatiod curves oflow carbon steel in 5n hci "i"t"i',i"g jiii.** i"libitor concentration at 30oc' '_ rq cdrbof f r t . 5 l a n a n r r i r a d , o r p l i o r i ' o l h e r n o ' r h i u l r r ' ^ ^ . i , r " i n d i l t . ' . n ' n o n . t i r y o f h c l d c i d s o l l l o r d r { u 1 t @ g 3 8 3 4 t e g 3 1 7 5 ( 1 9 9 0 ) . m . a . q u r a i s k i , c o o s s c r ' ' € fis.3 polarizalion curves oflow carbon steel in 3n sci """i"i"i"g ain"*", inhibitor concentration at 30"c references l g . g e o r g e , c o r r o s i o n t a x c s , ( 1 9 7 4 ) 2 . j . m . s y k c r , b r ' c o r [ o s j 2 5 . 3 . m . a j m a l , a s . m i d e e n , l n h i b l t o r , n a c e , l l o l r s t o l r ' iri!r. 2 polarization cunes oflow carbon sleel in ln hci ''?oirtoi"ing aifi","* i"libilor concentntion at 30'c . . ' n i r i i l l l l i " t . * , o ' \ c i . r r 8 ' | 1 r o o s ' i'::h*"li;:lt o l;:l'f"',lx:l"j.li '"i "\lj'.', 1; r 'ii"lllll, m, m.sc rhesis, univelsitv or baghdad ,.f.ll3];*, *o r. candi, material perromrance' rulv n.lslrt]"r, ", m.sc rhesis irniversitv or bashda' ( 1 9 8 8 ) . 5 0 i j c p e v o l . b n o . 1 ( [ , a r c h 2 0 0 7 ) ijcpe vol.9 no. 2 (june 2008) iraqi journal of chemical and petroleum engineering vol.9 no.2 (june 2008) 9-15 issn: 1997-4884 the effect of ageing on physical and chemical properties of asphalt cement abdul-halim abdul-karim mohammed, khalid morshed * chemical engineering department college of engineering university of baghdad – iraq abstract two grades of paving asphalt with penetration of 46 and 65 are studied for determining changes in their physical and chemical properties caused by ageing. the ageing process has been conducted on two petroleum paving asphalt cement using thin film oven test at 150, 163 and 175 c, and ageing time 5, 10,15, 20, 25 and 30 hours. the effect of ageing time and temperature on penetration, kinematic viscosity, softening point, solubility in trichloroethylene, heat loss and changes in chemical composition are investigated. the results of thin film oven test process indicte that the asphaltenes concentration of all aged asphalt increases with increasing ageing time, while the opposite was observed for polar-aromatic and naphthenearomatic. the saturate of low penetration grade asphalt is higher than that for high penetration grade asphalt and remained unchanged with ageing time. th kinematic viscosity and softening point seem to increase with increasing ageing time, while the penetration decreases with increasing ageing time. the di of aged asphalt inreases with increasing ageing time. introduction asphaltenes and polar-aromatic play a fundamental role in determining the mechanical and rheological properties of asphalts (penetration index and kinematic viscosity with ageing time and temperatures). 0ther important asphalt properties such as temperature susceptibility coefficient and characterizing factor were depended on the quantity of the asphaltenes and polar-aromatics. asphalt separation procedure is based on solubility in normal heptane followed by adsorption chromatography of the soluble portion [1]. the term age hardening is used to describe the phenomenon of hardening. hardening is primarily associated with loss of volatile components in asphalt ageing during the services. this factor causes an increase in viscosity of the asphalt and an increase in marshal stability. durability of asphalts is a prime consideration in the economics of all asphalts contractions. asphalts highway systems present the more obvious and perhaps the most important area in which asphalt performance is observed. the term durability during the time connotes a pavement life of about 75 years. the hardening show by an asphalt and service conditions, was for a long time taken as the best measure of its economic value. resistance to deterioration is a term used to some extent, but it does not seem appropriate since durability under service conditions is frequently affected by changes that, in the strictest sense [2]. traxler [3] measures age hardening with a falling coaxial cylinder type of viscometer, allowing sample to age. important researches by this investigator showed that viscosity increases after long time periods and is largely diminished by heating. asphalt composition is largely dependent upon the crude from which it was derived. composition as used in corbett [4] research is based upon the qualitative determination of the four generic fractions found in all university of baghdad college of engineering iraqi journal of chemical and petroleum engineering the effect of ageing on physical and chemical properties of asphalt cement 10 ijcpe vol.9 no. 2 (june 2008) asphalts, using the proposed astm procedure. each fraction differs considerably in color, density and aromatic carbon content. an asphalt meeting a given specification is thus a composite of these quantities, of which the flow properties. several asphaltic material and constituent groups (asphaltenes, petroleum resins, asphaltic resins and oils) subjected to oxygen in a closed system under atmospheric pressure at about 204 °c. the volume of oxygen absorbed by each material and fraction was measured. asphaltenes oxidized but the oils were quite resistant at the temperature used. the oxidized asphaltenes contained considerable amount of carboids (up to 96 %) after 3 hours in the oxygen atmosphere. carboids are insoluble in carbon disulphide [5]. the durability of asphalt as measured by its hardening in the dark was investigated. thin films of asphalt on sand grains were used and the volume of oxygen observed by gram of asphalt was determined. also, 5-mm thick films of asphalts on glass plates were exposed to air in the dark at fixed temperature for many weeks. samples were removed at intervals and the increase in viscosity caused by the ageing determined by means of the microfilm viscometer. this general method was modified and applied by exposing a 5 mm films of asphalt to ageing on glass plates for 2 hours at 107 c [6] .the hardening which occur is determined by measuring the viscosity of the asphalt before and after ageing. the durability is reported as an ageing index which is the ratio of the viscosity of the aged sample to that of the original, both viscosities having been determined at the same shear rate. a low ageing index signifies more durable asphalt. the original viscosity is obtained from film prepared in the same manner but not aged. ishaiet [7] have adopted the durability index to reflect the relationship between ageing and the internal colloidal structure of asphalt. this index is given by the ratio of the sum of the asphaltenes (a) and saturates(s) to the sum of the polar-aromatics (p a) and naphthenearomatics (n a). di = ( a + s ) / (p a + n a ) (1) rosttler [8] describes the asphaltene fraction as the component of asphalt primarily responsible for asphalt viscosity and colloidal behavior due to its limited solubility in the remaining components. he concluded that the asphaltenes are kept dispersed by the peptizing ability of the nitrogen bases, on other hand, the paraffin tend to reduce solubility, so the increasing amount of this constituent in relation to the nitrogen bases would lead to increasing gel characteristics. this work deals with the study of factors affeting the quality of different asphalt cements based on ageing time and temperature. experimental work raw material two grades of petroleum asphalts are supplied from daura refinery. the physical and chemical properties of these asphalts are presented in table 1. chemicals 1. alumina f-20 (28-200 mesh) chromatographic grade is used for separation of hydrocarbon groups from the petroleum asphalts. 2. normal heptane. 3. trichloroethylene (tce). 4. benzene. 5. toluene. test methods 1. durability test the standard thin film oven test (astm-d 1754) has been employed to aged the asphalt film at different temperatures and times for various types of asphalt cements. all aged samples have been tested for penetration, kinematic viscosity, softening point, heat loss and solubility in trichloroethylene. separation of asphaltenes, polar-aromatics, naphthene-aromatics and saturates were carried on all aged samples. the changes in physical properties and chemical composition of asphalt cements due to the effect of heat and air are evaluated by thin-film oven test. in all tests 3.2 mm film thickness of asphalt cement is placed in cylindrical pans in an oven maintained at temperatures 150, 163 and 175 c for ageing intervals 5, 10, 15, 20, 25 and 30 hours. changes in the various physical and chemical properties after oven ageing are then determined. figure 1 shows the unit of the laboratory durability test details about the test method were presented elsewhere [9]. 2. fraction composition (astm-d 2024). the precipitation of asphaltenes is applied for all petroleum asphalts and aged samples at temperature range of 150-170 c and time of 5-30 hours. the asphaltenes precipitation carried out by normal heptane. ten grams of the sample was dissolved in 150 ml of normal heptane and warmed up to 35 c with stirring for 5 minutes. the mixture of asphalt sample and solvent was allowed to stand for 30 minutes at room temperature and then filtered with buchner funnel having a fine porosity filter disk. the precipitate was washed four times with 50 abdul-halim abdul-karim mohammed, khalid morshed 11 ijcpe vol.9 no. 2 (june 2008) ml of n-haptane. the weight of solid precipitate is calculated as weight percent of asphaltenes. the fraction soluble in n-heptane was evaporated and further fractionated by adsorption chromatography. group composition for all raw and aged asphalts is determined by adsorption chromatography. a glass percolation column (20 mm diameter and 400 mm hieght) was filled with 300 g of activated alumina f-20. a 500 ml separating funnel containing the deaspaltened sample was put in the top of the column. the deaspaltened asphalt was diluted with nheptane.and allowed to percolate through the alumina bed with n-heptane. then a defined quantity of effluent (saturates) was collected from the bottom of the column. the separating funnel was removed from the top of the column, then a benzene-toluene mixture (1:1) was charged to the top of the column. the mixture dissolved the polar-aromatics fraction which drawed from the bottom of the column. the alumina column was then percolated with trichloroethylene for naphthene-aromatics removal from the bottom of the column. the percent weight of each fraction was calculated after solvent stripping. 3. penetration penetration is a test for the consistency of asphalt. it is based on a standard needle entering asphalt under fixed conditions. the depth of the penetration of the standard needle into the material to be tested within 5 seconds, with a load of 100 g at 25 c is measured in this standard test. the penetration is measured in 0.1 mm. 4. softening point asphalt with high viscosity like solid is soften gradually on heating. the softening temperature determined at described condition is called softening point. the softening point (ring and ball test) is the temperature at which the asphalt layer placed in a standard ring touches the plate under the ring due to the weight of a ball of definite mass and size. 5. viscosity the kinematic viscosity test according to the astmd 3120 is measured by using a gravity flow viscometer. the viscometer is putting in a bath at constant temperature. the molten asphalt is charged to the viscometer up to the filling line. the viscometer with the asphalt remains in the bath at test temperature for a defined period of time to make sure that the viscometer with the asphalt is at test temperature. fig. 1: scheme of airflow for durability test results and discussion the thin-film oven test has been employed to age the asphalt at a range of temperature 150 to 175 c and a range of time 5 to 30 hours. all aged samples have been tested for penetration, kinematic viscosity, softening point, heat loss and solubility in trichloroethylene. further more, the aged samples were separated into asphaltenes,naphthene-aromatics, polar-aromatics and saturates. figures 2-7 show the influence of ageing time at different temperatures on physical properties of the different grades of petroleum asphalts. the increase in ageing time from 5 up to 30 hours causes an increase in consistency to flow and loss in volatile. for example, for paving petroleum asphalt grade 60-70 the penetration and softening point at 163 c were 46 and 54 c, respectively for ageing time 5 hours, while they were 43 and 55 c,respectively for ageing time 10 hours. this is due to the conversion of the naphthenearomatics and polar-aromatics to asphaltenes, which lead to decreasing of penetration and increasing of softening point. figures 8-15 show the influence of ageing time at different temperatures on chemical composition change of the asphalts. these figures indicate that the asphaltenes increase with increasing of ageing time, while naphthenearomatics, polar-aromatics and saturates decrease with increasing ageing time.the increase in asphaltenes is due the effect of ageing on physical and chemical properties of asphalt cement 12 ijcpe vol.9 no. 2 (june 2008) to the partial conversion of naphthene-aromatics, polararomatics and saturates to asphaltenes. figures 16 and 17 indicate that durability index increases with ageing time increasing. the increase in durability index is due to increase in the asphaltenes and decrease in naphthene-aromatics and polar-aromatics with ageing time increasing.these results agree with the results obtained by tuffour for bitumenious materials [2]. figures 18 and 19 show the effect of ageing time on the percentage of heat loss of the aged samples, these figures indicate that the percentage of heat loss increase with ageing time increasing. this may be due to partial evaporation of the oil from the asphalt during ageing. table 2 is summarized the range of durability index of asphalts at different ageing temperatures. this table indicates that low penetration petroleum asphalt cements is less susceptible to ageing time than soft asphalt. this is because the saturates fraction of petroleum asphalt increases the resistance to flow. the heat treatment of petroleum asphalt during vacuum distillation affects its physical and chemical properties, so it become high susceptible to ageing time. table 1 physical and chemical properties of petroleum asphalt cements table 2 the change durability index(di) after ageing time 30 hours at different temperature. fig. 2 influence of aging time on penetration of petroleum asphalt grade 60-70 at different temperature. fig. 3: influence of aging time on kinematics viscosity of petroleum asphalt grade 60-70 at different temperature. characteristics grade 60-70 grade 40-50 range of di at, 150 c 163 c 175 c increase in di at, 150 c 163 c 175 c 0.150-0.811 0.150-0.927 0.150-1.087 0.661 0.777 0.937 0.759-1.361 0.759-1.477 0.759-1.660 0.602 0.718 0.901 abdul-halim abdul-karim mohammed, khalid morshed 13 ijcpe vol.9 no. 2 (june 2008) fig. 4: influence of aging time on softening point of petroleum asphalt grade 60-70 at different temperature. fig. 5: influence of aging time on penetration of petroleum asphalt grade 40-50 at different temperature. the effect of ageing on physical and chemical properties of asphalt cement 14 ijcpe vol.9 no. 2 (june 2008) abdul-halim abdul-karim mohammed, khalid morshed 15 ijcpe vol.9 no. 2 (june 2008) conclusions 1. the asphaltenes content for paving asphalt increase with ageing time at different temperatures. the asphaltenes content is ranged from 17.89 to 40.00 % at ageing time from 5 to 30 hours at different temperatures. 2. part of the polar-aromatics, naphthene-aromatics and saturates is converted to asphaltenes with ageing time and temperature increasing. this lead to decrease the percentage of polar-aromatics, naphthene-aromatics and saturates in the aged asphalt. 3. the durability index for aged asphalt increases with ageing time and temperature increasing. reference 1. speight, j. g., the desulfurization of heavy oils and residua, new york, 1981. 2. tuffour, y. a., proceeding of the association of asphalt paving technologies, 37, 1968. 3. traxler, r. n., pro. assoc. of asphalt paving technologies, 37, 1968. 4. corbett, l. w and petrossi, u., i and ec, prod. res. dev., 17, 4, 342, 1978. 5. barth, e. j., asphalt science and technology, new york, 1968. 6. shalebiy, a., can. civ. eng. j., 29, 135-144, 2002. 7. ishai, i., astm journal of testing and evaluation (jteva) ,5, 3, may, 1987. 8. rostler, f. s, i and ec, 41, 598-608, 1949. 9. aweed, kh. m, phd thesis, college of eng., university of baghdad, 2004. iraqi journal of chemical and petroleum engineering vol.15 no.3 (september 2014) 1-7 issn: 1997-4884 treatment of slack wax by thermal cracking process abdul halim a.k mohammed and saleem mohammed obeyed chemical engineering department-college of engineeringuniversity of baghdad abstract this work deals with thermal cracking of slack wax produced as a byproduct from solvent dewaxing process of medium lubricating oil fraction in al-dura refinery. the thermal cracking process was carried out at a temperature ranges 480-540 ºc and atmospheric pressure. the liquid hourly space velocity (lhsv) for thermal cracking was varied between 1.0-2.5 . it was found that the conversion increased (61 83) with the increasing of reaction temperature (480 540) and decreased (83 63) with the increasing of liquid hourly space velocity (1.0 2.5). the maximum gasoline yield obtained by thermal cracking process (48.52 wt. % of feed) was obtained at 500 ºc and liquid hour space velocity 1 . the obtaining liquid product at the best operating condition 500 ºc and lhsv 1 was fractionated into wide range fractions. based on the determination of some properties for the distilled fractions and comparison (these properties with that required by standard requirements) it is possible to use the fractions of cracking products as a component for production of automobile gasoline, domestic kerosene, light diesel fuel and basic lubricating oils. keywords: cracking slack wax. introduction the petroleum wax is the byproduct of a dewaxing process of lubricating oil fractions; the de waxing operation removed relatively small proportion of wax components from a large proportion of oil to produce slack wax, generally brown in color and has oil content between 5-25%. the commercial slack wax contains 79-89 wt. %. of paraffins and has a melting point in the range of 48-55 ºc and flash point of about 150 ºc [1, 2]. the slack waxes are also reported to contain (0.5-0.7) % wt. of sulfur and to have traces of water [3, 4]. thermal cracking reactions are those that occur in the temperature range of (460-540 ºc) to a point at which the bonds that hold a molecule together are broken. this breaking of bonds results predominantly in an increase in smaller molecules. however, breaking of bonds also leads to free radical formation, which can also result in subsequent polymerization or condensation reactions [5, 6]. cracking reaction starts to occur at a temperatures of about 315-370 ºc depending on the hydrocarbon nature of the material being cracked. depending on feed stock type and product requirement thermal cracking iraqi journal of chemical and petroleum engineering university of baghdad college of engineering treatment of slack wax by thermal cracking process 2 ijcpe vol.15 no.3 (september 2014) -available online at: www.iasj.net can be carried out over a wide range of temperature from 450-750 ºc and at pressure varying from atmospheric to 70 bars [7]. the objective of the present work is to study the thermal cracking processes of slack wax at different operating conditions in continuous laboratory unit. experimental work 1. feed stock slack wax obtained from the solvent dewaxing process from al-durah refinary was used as a feed stock in this investigation. the properties of slack wax are shown in table 1. table 1: slack wax properties characteristics value viscosity, cst. at 40 ºc 13.8 specific gravity, at 15.6 ºc/15.6 ºc 0.804 pour point, ºc 48 color dark neutralization number, mg. koh/g. oil 0.075 melting point, ºc 76 oil content, % wt. 20 2. the experimental procedure the thermal cracking experiments were carried on a laboratory continuous flow unit shown in fig. 1. the desired quantity of molten feed slack wax was pumped from the feed storage by a dosing pump to the preheater and then the preheated feed entered the reactor section. the reactor consisted of a stainless steel tube with 3.0 cm inside diameter and 60 cm length. the reactor was heated and controlled automatically by three heaters insulated by two layers of insulation to minimize heat losses. the temperatures inside the reactor were measured by three thermocouples fixed inside the reactor at three different locations. the vapor and liquid products were discharged to the condenser and the condensates were collected alone, for all runs in various operating conditions. the uncondensed gases were collected in gas collector unit. the duration of the time for all experiments was kept at 30 minute. the experiments took place at temperatures 480, 500, 520 and 540 ºc and liquid hour space velocities 1.0, 1.5, 2.0 and 2.5 . 1-feed reservoir: 2dosing pump; 3-preheater; 4one way valve; 5reactor system; 6temperature controller; 7condenser; 8flow meter; 9control valves; 10separator; 11cooling machine. fig. 1: schematic flow diagram of laboratory continuous cracking unit abdul halim a.k mohammed and saleem mohammed obeyed -available online at: www.iasj.net ijcpe vol.15 no.3 (september 2014) 3 liquid product distillation 1. general distillation the general distillation of cracking liquid products was done according to astm d86 for separation fractions up to 220 ºc called gasoline while the residue above 220ºc was called light cycle oil (lco). 2. wide range fractionation distillation of thermal cracking liquid products into wide range fractions was achieved in micro topp distillation unit according to astm d-5236. the atmospheric distillation was continued until the temperature of column flask reached 350 ºc and then the vacuum distillation at 60 mm hg. was carried on until the top temperature of column reached 375 ºc (520 ºc at 760 mm hg.). during the wide range fractions for thermal cracking products, the following fractions were separated : light naphtha (up to 75ºc), heavy naphtha (75-175 ºc), kerosene (175-225 ºc), gasoil (225-390ºc), light lubricating oil (390430 ºc), medium lubricating oil (430450 ºc) and heavy lubricating oil (450520 ºc) according to 760 mm hg., or (260-280 ºc), (280-320 ºc), (320-375 ºc) according to 60 mm hg. results and discussion the effect of operating conditions the effect of liquid hour space velocity (lhsv) in the range 1.0-2.5 on slack wax conversion and the yield of gases, gasoline, light cycle oil and coke were studied at temperature ranges of 480-540 ºc. fig. 2 shows the effect of lhsv on the slack wax conversion at different temperatures. as shown in this figure, the slack wax conversion increases with decreasing of lhsv at constant temperature. this means that the conversion of slack wax is a function of reaction time, the increasing of the contact time of the feed molecules increases the slack wax conversion and inversely proportional to the feed flow rate [8]. the decreasing lhsv at constant temperature increases the yield of gases, gasoline, coke, and decreases the light cycle oil. clear pictures for cracking products distribution at different lhsv and constant temperatures were presented in figures 3→6. fig. 2: effect of lhsv on the slack wax conversion at different temperatures 0 10 20 30 40 50 60 70 80 90 0 0.5 1 1.5 2 2.5 3 c o n v e rs io n ( % w t. ) lhsv (1/hr) t=480 c t=500 c t=520 c t=540 c treatment of slack wax by thermal cracking process 4 ijcpe vol.15 no.3 (september 2014) -available online at: www.iasj.net fig. 3: effect of lhsv on thermal cracking products yield at 480 ºc fig. 4: effect of lhsv on thermal cracking products yield at 500 ºc fig. 5: effect of lhsv on thermal cracking products yield at 520 ºc fig. 6: effect of lhsv on thermal cracking products yield at 540 ºc 0 20 40 60 80 0 0.5 1 1.5 2 2.5 3 % w t f e e d lhsv (1/hr) gasoline l.c.o coke gas 0 10 20 30 40 50 60 0 0.5 1 1.5 2 2.5 3 % w t w t. f e e d lhsv (1/hr.) gasoline l.c.o coke gas 0 10 20 30 40 50 60 0 0.5 1 1.5 2 2.5 3 % w t. f e e d lhsv (1/ hr.) gasoline l.c.o coke gas 0 10 20 30 40 50 60 0 0.5 1 1.5 2 2.5 3 % w t. f e e d lhsv (1/ hr.) gasoline l.c.o coke gas abdul halim a.k mohammed and saleem mohammed obeyed -available online at: www.iasj.net ijcpe vol.15 no.3 (september 2014) 5 fig. 7: plot of lnk vs. the effect of temperature ranges (480-580) on the slack wax conversion and the yield of gases, gasoline, light cycle oil and coke were studied at lhsv range 1.0-2.5 . the slack wax conversion increases with increasing temperature. this may be due to acceleration inter molecular motions, assisting the transformations of the reactants into new compounds and thus enhancing the rate of chemical reaction, as mentioned also by decroopcq [9]. kinetic of thermal cracking the reactions proceeding in thermal cracking obey first order shown in equation 1 [10]. the integral method of analysis always puts a rate of equation to the test by integrating and comparing the predicted concentration (c) versus time (t) curve with the experimental concentration (c) versus (t) data [11]. = k ca = …(1) the fractional conversion is defined as the fraction of reactant converted into product. for constant density, system volume does not change: …(2) differentiation equation 2 gives: …(3) and hence equation 1 becomes: = k (1 ) …(4) integration gives: = ln = ln = ln …(5) the activation energy of cracking reactions can be estimated by arrhenius equation was 80.18 kj/ mole. plotting ln k versus 1/t as shown in fig.7 gives a straight line with slope equal to (-e/r). the possibility of slack wax cracking uses properties of light naphtha, heavy naphtha, kerosene and gas oil produced by thermal cracking at temperature 500 ºc and lhsv=1.0 are listed in table 2. 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.22 1.24 1.26 1.28 1.3 1.32 1.34 ln k 1/t * 10−3 k-1 thermal cracking treatment of slack wax by thermal cracking process 6 ijcpe vol.15 no.3 (september 2014) -available online at: www.iasj.net table 2: the properties of liquid products characteristics light naphtha heavy naphtha kerosene gas oil specific gravity, 15.6 ºc/15.6 ºc 0.698 0.783 0.80 0.885 api gravity 71.05 49.21 44.45 28.38 sulphur content, wt.% 0.03 0.07 0.092 0.097 net heat, cal/gr. 11375 11100 10272 11324 octane number 87.04 85.35 --------- smoke point, mm --------30 --- aniline point, ºc --------83 diesel index ------------51.5 pona analysis, wt.% n-paraffin 38.64 20.05 35.43 40.49 iso-paraffin 36.29 16.65 24.32 24.73 naphthene 5.10 8.18 6.10 5.29 olefin 19.17 50.20 21.12 17.50 aromatic 0.75 4.90 13.027 11.98 the light and heavy naphtha obtained by thermal cracking have high octane number and low sulphur content, so it is possible to use these naphtha as a component for automobile gasoline production. kerosene obtained by thermal cracking low aromatic and sulphur content and high smoke point compared with iraqi commercial value, so it is easy to be used as a component for domestic kerosene production. the gas oil has high n-paraffin, iso paraffin and diesel index and low aromatic and sulphur content, so it can be used as a good component for light diesel fuel and fuel oil production. the properties of light, medium and heavy lubricating oils produced from thermal cracking are listed in table 3. these oils have high viscosity index and flash point and they have very low of ash and carbon residue and acceptable viscosity compared with commercial, but the pour point is very high. because of the high value of pour point, these fractions should be blended with respective oil fractions; the dewaxing process for pour point is going to decrease. table 3: the properties of light, medium and heavy lubricating oils type test results of thermal cracking iraqi commercial value [12] temp. wide distillation, ºc 390-430 430-450 450-520 viscosity at 40 ºc, cst. 8.3074 7.0282 --------- viscosity at 100 ºc, cst. 2.8895 2.5455 3.175 ------ specific gravity at 15.6 ºc/15.6 ºc 0.795 0.781 0.782 ----- viscosity index 200.56 193.248 -----95 min. pour point, ºc -----27.8 ------6 ash content, wt. % nil nil ----------- carbon residue, wt.% 0.2559 0.0295 nil ------------ flash point, ºc 200 200 202.0 200 min. conclusions 1the slack wax conversion increases with the decreasing of lhsv at constant temperature and increases with increasing the temperature. 2the decreasing of lhsv at constant temperature for thermal cracking abdul halim a.k mohammed and saleem mohammed obeyed -available online at: www.iasj.net ijcpe vol.15 no.3 (september 2014) 7 increases the cracking yields of gases, gasoline, and coke and decreases the light cycle oil. 3the increasing in the reaction temperature for thermal cracking firstly increases the gasoline yield and then higher temperature, over cracking occurance gives lower gasoline yield, while the yield of gases increases. 4based on the maximum of the gasoline yield, it could be said that the best cracking temperature was 500 ºc for thermal cracking, while the best liquid hour space velocity was 1.0 5the properties of light and heavy naphtha like octane number and sulphur content which are produced by thermal cracking are acceptable compared with these required by iraqi standard value, so they could be used as a component for automobile gasoline production. references 1speight, j.g. (1999). "the chemistry and technology of petroleum," 3 rd ed. marcel dekker, new york. 2crawford, c. d., bharvani, p. r., and chapel, d. g. (2002). integrating petrochemicals into the refinery. hydrocarbon process” 7, 35-38.. 3gary. h., and handwerk, g. h. (2001) “petroleum refining technology and economics”. 4 th ed. marcel dekker, new york. 4jones, d. s. j, and pufado, p. r. (2005). "handbook of petroleum processing." springer, berlin. 5hobson, g.d., (1975) "modern petroleum technology", applied science publishers ltd, 1973; reprinted. 6seyfried f. (2003) “renewable fuels from advanced power trains”. bioenergy enlarged perspectives conference. organized by eu, budapest, hungary. 7alan g. lucas (2001) "modern petroleum technology" vol.2 downstream new york. 8kostas s. triantafyllidis and angelos a. lappas (2007)" clean fules from the catalytic cracking of fischer – tropsch waxes greece. 9denial decroopcq (1984) “catalytic cracking of heavy petroleum fractions”, imprimerir louis-jean, paris. 10a. alkilani. haitham m. s. taher a. al-sahhaf (2010) “fundamental of petroleum refining". 11levenspiel, o., (1999) "chemical reaction engineering" john wiley and sons inc. 12marketing specifications of iraqi petroleum products 3ed (1999). 13l. z. pillion (2005) “interfacial properties of petroleum products”. 14jones, d.s., and pujad, p, r., (2006) "handbook of petroleum processing", published by sapringer. 15saleem, m. o., (2013) “treatment of slack wax by thermal and catalytic cracking processes.” ph.d. thesis, university of baghdad, chemical engineering department, july. ijcpe vol.10 no.2 (june 2009) iraqi journal of chemical and petroleum engineering vol.10 no.2 (june 2009) 35-42 issn: 1997-4884 phosphorus removal from water and waste water by chemical precipitation using alum and calcium chloride sawsan a. m. mohammed and haider abbas shanshool chemical engineering department college of engineering university of baghdad – iraq abstract phosphorus is usually the limiting nutrient for eutrophication in inland receiving waters; therefore, phosphorus concentrations must be controlled. in the present study, a series of jar test was conducted to evaluate the optimum ph, dosage and performance parameters for coagulants alum and calcium chloride. phosphorus removal by alum was found to be highly ph dependent with an optimum ph of 5.7-6. at this ph an alum dosage of 80 mg/l removed 83 % of the total phosphorus. better removal was achieved when the solution was buffered at ph = 6. phosphorus removal was not affected by varying the slow mixing period; this is due to the fact that the reaction is relatively fast. the dosage of calcium chloride and ph of solution play an important role in phosphorus removal. the removal efficiency increases with increasing ph, and the optimum dosage of cacl2 was 60 mg/l. alum demonstrated much better results in phosphorus removal than cacl2. keywords: chemical treatment, phosphorus removal, alum, calcium chloride, water treatment, west water treatment introduction phosphorus present in domestic wastewater is an important macro-nutrient for plant and microorganisms growth. the discharge of large quantities of this nutrient into natural receiving sources raises the growth of algae and results in eutrophication of lakes and streams (banu, et al., 2008). this can in turn disturb the balance of organisms present in water and affect water quality, mainly through the depletion of oxygen level as the algae decay. reduced oxygen level can have harmful effects on fish and other aquatic life, causing reduction in biodiversity. the load of phosphorus discharged to receiving waters comes from various groups of sources of which the main sources are agricultural use of fertilizers, domestic and industrial wastewater, and atmospheric deposition (plaza et al., 1997). phosphorus removal techniques fall into three main categories; physical, chemical and biological. in a biological treatment plant, it is necessary to transfer phosphate from liquid to the sludge phase, and the removal efficiency usually does not exceed 30%, which means that the remaining phosphate should be removed by other techniques. chemical precipitation is also widely used for phosphate removal. the precipitation of calcium phosphate from wastewater is an important physiochemical process for phosphorus removal and it becomes increasingly significant for phosphorus recovery, since from the industry's viewpoint, it is far more promising to recover phosphorus as calcium phosphates than other forms because it can be valorized in agriculture as a slightly soluble fertilizer (hosni, et al., 2007). agents used to precipitate dissolved phosphorus are salts of metals, calcium (ca+2), iron (either fe+2 or fe+3), or aluminum (either alum, al2 (so4)3. 18h2o or sodium illuminate, na2al2o4). the chloride and sulfate salts of fe+2 and fe+3 can be used (droste, 1997). basic chemicals for precipitation were lime alone or lime in conjunction with alum, ferric sulfate, burnt magnesia or charcoal, ferric chloride. precipitation of phosphorus by addition of lime and alum in advanced wastewater treatment technology and different methods to recover aluminum and lime has been described by clup and clup university of baghdad college of engineering iraqi journal of chemical and petroleum engineering phosphorus removal from water and waste water by chemical precipitation using alum and calcium chloride 2 ijcpe vol.10 no.2 (june 2009) (1971). kershaw in 1911 mentioned most common precipitants applied in great britain including: o lime o alumino-ferric o ferric sulphate o sulphuric acid o ferrozone o lime and ferrous sulphate o lime chlorine most of these chemicals have been proven to precipitate phosphorus and are in use even today (rybicki, s., 1997). since the 1960’s major efforts have been made towards phosphorus removal (jenkins 1971). in general; the degree of phosphorus removal by chemical precipitation is affected by many factors, such as ph, alkalinity, coagulant dose, speed of mixing and other interfering substances (james, et al., 2003). chemical precipitation or flocculation of biochemically treated wastewater effluents have been investigated by rudolf (1947), owen (1953), lea et al. (1954). these investigations have been discussed by stumm (1962). in general these investigations had shown that significant amounts of phosphorus can be removed by alum and iron flocculation or lime precipitation (malhotra, et al., 1964). the chemistry of phosphate formation is complex because of complexes formed between phosphate and metals and between metals and ligands in the wastewater. side reactions of the metals with alkalinity to form hydroxide precipitates are another factor to be considered. the common precipitates formed by metals are given in table (1) along with the optimal ph range for phosphate precipitation (droste, 1997). the aqueous chemistry of alum is extremely complex and when added to water, aluminum enters into a series of complicated reactions. the aluminum ions become hydrated and form monomeric and polymeric species and solid precipitates. hem et al, 1976, mention that the formation of polynuclear species in dilute solution is a stepwise process involving a deprotonation-dehydration mechanism. firstly, alum is hydrated. hydrated aluminum ions are deprotonated and two deprotonated octahedral can then join to form a dimmer. dimers can join to form a 6-member chain structure by the same deprotonation-dehydration mechanism. these six membered rings may then coalesce further by continued polymerization, resulting in a higher ratio of structural hydroxyl to aluminum. these steps can be summarized in a very simplified and short manner in fig. (1) (georgantas and grigoropoulou, 2006). in recent years considerable attention has been paid to the chemistry of alum and mainly in its hydrolyzed products also known as poly-aluminum salts (boisvert et al., 1997). these salts have shown to offer a number of benefits in comparison to their precursor, alum, such as lower residual soluble al and lower preor postph adjustment needed. therefore, these salts have attracted great interest and extended research has been devoted into its preparation under controlled conditions and characterization (benschoten and edzwald, 1990, sincero, 2003). the aim of this investigation was to study the feasibility of phosphate removal from aqueous solutions by calcium chloride and alum. the process was examined under different values of ph, the dosage of coagulant and performance parameters. table (1) phosphate precipitates (jenkins and hermanowicz, 1991) metal precipitates ph range comment ca +2 various calcium phosphates, e.g.ca3(po4)2,ca5(oh)(po4)3, cahpo4 caco3 ≥ 10 ≤ 9.5 produces lowest residual p concentrations. the alkalinity of the water determines the dose because of formation of caco3. residual p in the range of 1-2 mg/ lit. fe +2 fe3(po4)2, fex(oh)y(po4)3, fe(oh)2, fe(oh)3 68.5 there will be some oxidation of fe +2 to fe +3 . fe +3 fex(oh)y(po4)z, fe(oh)3 68.5 al +3 alx(oh)y(po4)z. al(oh)3 68.5 al(oh2)6 +3 al(oh)(oh2)5 +2 + h + 2al(oh)(oh2)5 +2 al2(oh)2(oh2)8 +4 + 2 h2o → al6(oh)12 +6.12h2o al6(oh)12 +6.12h2o → al10(oh)22 +8.16h2o → al24(oh)60 +12 . 24h2o al32(oh)82 +14. 28h2o → al54(oh)144 +18.36h2o fig. 1 proposed mechanism for alum hydrolysis and polymerization in water 3 ijcpe vol.10 no.2 (june 2009) experimental work the coagulation experiments were carried out at laboratory temperature using a jar-test (floc tester, zeitschaltuhr) with a six paddle stirrer. in each of the tests, 1 liter of phosphate solutions prepared from kh2po4 was taken in the jar. the ph was adjusted to the desirable level with the addition of alkali (1n naoh) or acid (1n hcl). the coagulants (alum and calcium chloride) were added under stirring. rapid mixing took place for 1 min. at a speed of 200 rpm, followed by slow mixing at 30 rpm for 30 min. the effects of slow mixing on phosphorus removal were carried out at varying times, namely 5, 10, 15, 20, 25, 30, respectively. the settling period lasted for 30 min. another experiment was made for the alum addition by buffering the phosphate solutions to ph=6 using few drops of a buffering reagent. the last is prepared by dissolving 136 g sodium acetate (ch3coona.3h2o) in water, adding 40 ml 1n acetic acid and diluting to 1 liter. after the settling period, samples were taken and analyzed for ph and phosphorus. the ph was measured by a digital ph – meter with glass electrode and saturated calomel electrode (oakton ph 2100 series manufactured by eutech instruments, singapore). a spectrophotometer (spectro sc, usa) was used for the analysis of phosphate in accordance with the standard methods (vanadomolybdo-phosphoric acid colorimetric method) . vanadomolybdo-phosphoric acid colorimetric method in this method, ammonium molybdate reacts with phosphorus to form molybdophosphoric acid. in the presence of vanadium, yellow vanadomolybdophosphoric acid is formed. the intensity of the yellow color is proportional to phosphate concentration vanadate – molybdate reagent was prepared by weighing (25 gm) of ammonium molybdate and dissolved in 250 ml of distilled water to form solution (a), then (125 gm) of ammonium metavanadate were dissolved in 200 ml of distilled water to prepare a solution to which is added (300 ml)of concentrated hcl to form a solution (b). solution a and b were mixed together and diluted to a liter volume, thereby forming a standard vanadate-molybdate reagent solution. phosphate standards (kh2po4) were prepared from the stock solution (1×10 -3 m kh2po4):0.1mm, 0.2mm, 0.4mm, 0.6mm by using 50-cm3 volumetric flasks for construction of a calibration curve. both samples and phosphate standards then prepared for absorbance measurements at 420 nm using the ammonium molybdate/ ammonium metavanadate color reagent by placing 25 cm3 of diluted sample solution in 50-cm3 volumetric flasks and adding 10 cm3 vanadate-molybdate reagent and diluting with distilled water. a blank was prepared in which 25 cm3 of distilled water was substituted for sample of phosphate standards (thomas and burqess, 2007). results and discussion phosphorus removal by alum effect of alum dosage on removal of phosphorus: the influence of al2 (so4)3.18h2o dosage on the phosphorus removal without ph adjustment is shown in fig. (2). a rise in alum dosage up to 80 mg/l increases the phosphorus removal. further addition of alum leads to a decrease in the phosphorus removal efficiency. the decrease in phosphorus removal efficiency after the optimum dosage was due to the restablization of colloidal suspension (ahmed et al., 2006). this is due to the fact that an increase in the dosage shifts the optimum ph (5.86.5) to an unfavorable range for phosphate removal, so the increase in the dosage is meaningless and it actually decreases the performance of the coagulant. 0 2 4 6 8 10 20 40 60 80 100 120 140 dosage of alum (mg/l) r e s id u a l s o lu b le p ( m g /l ) with ph control without ph control fig. 2 the influence of alum dosage on phosphorus removal the influence of ph on phosphorus removal phosphate removal as aluminum phosphate highly depends upon the ph of water. after alum was added into water, the ph of solution decreased. this is due to the fact that a part of alum was precipitated as the hydroxide forms and h+ was formed by the following reaction: al+3 + 3h2o → al (oh)3 ↓+ 3h+ below a ph range of 5.5 the aluminum ions are soluble and do not participate in the hydration and olation reactions necessary to make alum effective as a coagulant. also the formation of insoluble alpo4 according to the scheme: al+3+hnpo4n-3 alpo4+nh+ is not possible as alpo4 is soluble below ph=6 and above ph=8 (sedlak, 1991). on the other hand, when the ph level of the water is above 8 after the addition of the phosphorus removal from water and waste water by chemical precipitation using alum and calcium chloride 4 ijcpe vol.10 no.2 (june 2009) alum, the aluminum ions again become soluble (al(oh)4-), and the efficiency of coagulation is decreased (georgantas and grigoropoulou, 2006). after adding coagulant, the ph of water was more important than its initial ph. the effect of the initial ph of sample on the removal of phosphorus is presented in fig. (3). the data was obtained for total phosphorus removal over a ph range of 3 -11. in these runs an alum dosage of 80 mg/l was used and the initial ph of the sample was adjusted by the addition of naoh (1n) or hcl (1n). 0 1 2 3 4 5 6 7 8 9 10 3 4 5 6 7 8 9 10 ph after alum addition r e s id u a l s o lu b le p ( m g /l ) ph=3 ph=6 ph=8 ph=10 ph=11 fig. 3 effect of ph on the removal of phosphorus. in the case of ph=3, it did not play any role in the phosphorus removal, whereas at ph=6, the phosphorus removal was high at low dosage when compared to that of remaining ph. the increase in the dosage resulted in a decrease in the phosphorus removal for ph=6 rather than others. this is due to the rapid shifting of ph by alum dosage. in the ph 8, 10 and 11 the residual phosphorus decreases in the ph range of 5.7 to 6 which are similar to the findings of georgants and grigropolou (2006) and denham (2007). fig.(2) also shows that significantly better removal were achieved when the solution was buffered at ph=6, because when alum is added in the solution, ph drops rapidly at about ph= 4. at this ph the produced aluminum phosphate is redissolved releasing phosphate again. on the contrary, at ph= 6, aluminum phosphate is actually undissolved. effect of slow mixing time (kinetics) on phosphorus removal fig.(4) shows the effect of slow mixing time on the phosphorus removal for alum dosage of 40,60 and 80 mg/l. it is evident from fig.(4) that phosphorus removal was not affected by slow mixing time. the reason may be due to the fact that the phosphorus removal is relatively fast and equilibrium had been reached in less than 5 minutes. a similar behavior was observed by szabo et al., (2008) and georgantas and grigoropoulou, (2003). 0 1 2 3 4 5 6 7 8 9 10 0 5 10 15 20 25 30 time (min. at 30 rpm) r e s id u a l s o lu b le p ( m g /l ) 40 mg/l 60 mg/l 80 mg/l fig. (4): kinetics of phosphorus removal using alum. removal of phosphorus by calcium chloride effect of ph and cacl2 dosage on phosphorus removal variation of the phosphorus removal efficiency as a function of initial ph at different cacl2 dosage is shown in fig.(5). it shows that ph and cacl2 dosage play an important role in po4-3 removal. phosphate removal increases with increasing ph and cacl2 dosage, at ph= 11 the residual phosphorus passes from (5 to 3 mg/l) when cacl2 dosage passes from 40 to 60 mg/l. the ph effect can be explained by the change of orthophosphate compounds with ph (i.e. conversion of h3po4 h2po4 hpo4-2 po4-3 with increasing ph) (jenkins et al., 1971 and hosni et al., 2007). however cacl2 dosage larger than 60 mg/l has nearly no effect on phosphorus removal. 0 1 2 3 4 5 6 7 8 9 10 7 8 9 10 11 ph r e s id u a l s o lu b le p ( m g /l ) cacl2 = 40 mg/l cacl2 = 50 mg/l cacl2 = 60 mg/l cacl2 = 80 mg/l cacl2 = 120 mg/l fig. 5 phosphorus removal as a function of ph for various cacl2 dosages. sawsan a. m. mohammed and haider abbas shanshool 5 ijcpe vol.10 no.2 (june 2009) comparison between alum and calcium chloride regarding their efficiency to remove phosphorus fig.(6) shows the phosphorus versus ph for alum and cacl2 dosage of 80 mg/l. alum demonstrated much better results in phosphorus removal, being up to approximately 2 times better than cacl2 for the same dosage. 0 1 2 3 4 5 6 7 8 9 10 3 5 7 9 11 ph r e s id u a l s o lu b le p ( m g /l ) alum cacl2 fig.6 comparison between alum and calcium chloride regarding their efficiency to remove phosphorus. conclusions the phosphorus removal by alum was found to be highly ph dependent with an optimum ph of 5.7 to 6. at this ph an alum dosage of 80 mg/l removed 83 % of the total phosphorus. better phosphorus removal was achieved when the solution was buffered at ph = 6. phosphorus removal was not affected by varying slow mixing period; this is due to the fact that phosphorus removal is relatively fast. the dosage of cacl2 and ph play an important role in phosphorus removal, the removal efficiency increases with increasing ph, and the optimum dose of cacl2 was 60 mg/l. alum demonstrated much better results in phosphorus removal being 2 times better than cacl2 for the same dosage. references 1. ahmed, a. l., sumathi, s. and hameed, b. h., 2006,”coagulation of residue oil and suspended solids in palm oil mill effluent by chitosan, alum and pac”, chem. eng. j., 118, pp. 99-105. 2. banu, r.j., do, k. u. and yeom, i.t., 2008,"phosphorus removal in low alkalinity secondary effluent using alum", int. j. environ. sci. tech., v.5, no.1 pp. 93-98. 3. boisvert j.p., to t.c., beraak a., jolicoeur c., 1997, “phosphate adsorption in flocculation processes of aluminum sulphate and polyaluminum-silicate-sulphate” water research, v. 31, pp.1939-1946. 4. benschoten j.e., edzwald j.k., 1990 “chemical aspects of coagulation using aluminum salts ii.coagulation of fulvic acid using alum and polyaluminum chloride” water research v. 24, no12, pp. 1527-1535. 5. clup r.l. and clup g.l., 1971, advanced wastewater treatment, van nostrand reinhold comp. 6. denham, k., 2007,”chemical phosphorus removal and control strategies” msc. thesis. 7. droste,r.l., 1997,theory and practice of water and wastewater treatment, john wiley & sons, inc., new york. 8. georgantas, d.a. and grigoropoulou, h.p., 2003,"phosphorus removal from synthetic wastewater using spent alum sludge",8 th international conference on environmental science an technology, lemnos island, greece, 8 – 10 september. 9. georgantas, d.a. and grigoropoulou, h.p., 2006,"phosphorus removal from synthetic wastewater using alum and aluminum hydroxide” global nest j., v.8, no.2, pp. 121130. 10. hem s., white j, nail s., 1976, “structure of aluminum hydroxide gel i: initial precipitate”, journal of pharmaceutical. sciences, v. 65, no. 8, pp1188-1191 11. hosni, k., moussa, s.b. and amor, b., 2007,"conditions influencing the removal of phosphate from synthetic wastewater: influence of the ionic composition", desalination, 206, pp. 279-285. 12. james, m., ebeling sibrell, p. l., ogden, s. r. and steven s. t., 2003,”evaluation of chemical coagulation-flocculation aids for the removal of suspended solids and phosphorus from intensive recirculating aquaculture effluent discharge”, aquacult. eng., 29, pp. 23-42. 13. jenkins, d.; ferguson, j. f.; menar, a. b., 1971,”chemical processes for phosphate removal”, water res., 5, pp. 369–389. 14. jenkins, d. and hermanowicz, s. w., 1991, principles of chemical phosphate removal, 2 nd ed., lewis puplisher, pp. 91-110. 15. lea, w. l., rohlich, g. a. and katz, w. j., 1954,”removal of phosphates from treated phosphorus removal from water and waste water by chemical precipitation using alum and calcium chloride 6 ijcpe vol.10 no.2 (june 2009) sewage”, sewage industr. wastes, 26, pp. 261275. 16. malhotra, s.k., fred lee,g. and rohlich, a., 1964,"nutrient removal from secondary effluent by alum flocculation and lime precipitation", int. j. air water. poll, v. 8, pp.487-500. 17. owen, r., 1953,”removal of phosphorus from sewage plant effluent with lime”, sewage industr. wastes, 25, pp. 548-556. 18. plaza, e., levin, e. and hultman, b., 1997, phosphorus removal from wastewatera literature review, division of water resources engineering, department of civil and environmental engineering, royal institute of technology, stockholm. 19. rudolf, w., 1947,”phosphates in sewage and sludge treatment – effect on coagulation, clarification and sludge volume”, sewage wks j., 19, pp. 178190. 20. rybicki, s., 1997,"advanced wastewater treatment: phosphorus removal from wastewater", division of water resources engineering, royal institute of technology. 21. sedlak r., 1991, phosphorus and nitrogen removal from municipal wastewater, principles and practice, second edition, lewis publishers pp. 95. 22. sincero, a.p. and sencero, g.a., 2003, physicalchemical treatment of water and wastewater, crc press, iwa publishing, pp. 627-655. 23. stumm, w., 1962,”chemical elimination of phosphates as third stage sewage treatment, a discussion presented at the international conference on water pollution research, london. 24. szabo, a., taka´cs, i.,murthy, s., daigger, g. t.,licsko, i., smith, s., 2008, “significance of design and operational variables in chemical phosphorus removal”, water environ. res., v 80, no.5, pp.407416. 25. thomas, o., and burqess, c., 2007, uvvisible spectrophotometry of water and wastewater, elsevier. وكلوريد (الشب)ازالة الفسفور هن الوياه بطريقة الترسيب الكيوياوي باستخدام كبريتات االلوونيوم الوائية الكالسيوم سوسن عبد هسلن و حيدر عباس شنشول انعشاقتغذادجايعح تغذاد كهٍح انهُذسح –قسى انهُذسح انكًٍٍاوٌح : انخالصح ونهزا فًٍ eutrophication))انى عًهٍح انتحىل فً انحٍاج انًائٍح ٌعتثش انفسفىس يٍ انًىاد انًهىثح نهًاء و انتً تؤدي الٌجاد jar test)) جهاص فً هزِ انذساسح تى اجشاء سهسهح يٍ انتجاسب تاستخذاو. انضشوسي انسٍطشج عهى تشكٍضِ فً انًاء نقذ وجذ اٌ افضم قًٍح نهشقى انهٍذسوجًٍُ فً حانح استخذاو .افضم قًٍح نهشقى انهٍذسوجًٍُ وكًٍح انًادج انكًٍٍاوٌح انًضافح يٍ كًٍح انفسفىس انزائة فً % 83نتشوانتً تعًم عهى اصانح / يهغى80 وافضم كًٍح يستخذيح هً 6 – 5.5انشة هى يٍ نى تتاثش كفاءج االصانح تتغٍٍش .6انًاء وكاَت عًهٍح االصانح افضم عُذيا تًت انسٍطشج عهى قًٍح انشقى انهٍذسوجًٍُ عهى قًٍح . انضيٍ انالصو نهتحشٌك انثطئ ورنك نكىٌ انتفاعم سشٌع ايا فً حانح اصانح انفسفىس تاستخذاو كهىسٌذ انكانسٍىو فاٌ كًٍح انكهىسٌذ انًضاف وانشقى انهٍذسوجًٍُ نهًحهىل كاٌ نها دوس دنت انُتائج . نتش/ يهغى60وافضم قًٍح نكًٍح انكهىسٌذ هً 11نهشقى تانهٍذسوجًٍُ هى يهى فً عًهٍح انتشسٍة واٌ افضم قًٍح . عهى اٌ انشة اعطى كفاءج افضم فً عًهٍح تشسٍة انفسفىس تانًقاسَح يع كهىسٌذ انكانسٍىو available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.20 no.4 (december 2019) 27 – 33 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: ahmed n. hammadi, email: ah6616@gmail.com, name: ibtehal k. shakir, email: ibtehal_27@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. adsorption behavior of light naphtha components on zeolite (5a) and activated carbon ahmed n. hammadi a and ibtehal k. shakir b a ministry of oil – oil products distribution company – baghdad – iraq b college of engineering – university of baghdad abstract light naphtha is one of the products from distillation column in oil refineries used as feedstock for gasoline production. the major constituents of light naphtha are (normal paraffin, isoparaffin, naphthene, and aromatic). in this paper, we used zeolite (5a) with uniform pore size (5a) to separate normal paraffin from light naphtha, due to the suitable pore size for this process and compare the behavior of adsorption with activated carbon which has a wide range of pores size (micropores and mesopores) and high surface area. the process is done in a continuous systemfixed bed columnat the vapor phase with constant conditions of flow rate 5 ml/min, temperature 180 o c, pressure 1.6 bar and 100-gramweight of each adsorbent according to many other experiments on zeolite (5a) and choose the best conditions for comparison. the molecular sieve (5a) separated the normal paraffin (c4 – c8) from light naphtha feed with highest percentage removal reaching a (92.36 %) at the beginning of the process. activated carbon separated naphthene and aromatics with highest percentage removal reaching a (95.3 %) for naphthenes and a (100 %) for aromatics at the beginning of the separation process. the study shows the difference in physical adsorption behavior and the effect of pore size on these processes. keywords: light naphtha , zeolite (5a) , activated carbon , adsorption process received on 18/05/2019, accepted on 03/07/2019, published on 30/12/1029 https://doi.org/10.31699/ijcpe.2019.4.5 1introduction physical adsorption, a kind of adsorption depends on the potential of surface, shape, and structure of molecules. the principal thought of this type of separation is adsorbing at least one or more components from the blend without changing in compound synthesis[1]. the pore size of adsorbent is a very important factor. this belongs to the ability of components for penetrating to these tubes. light naphtha, for the most part, comprises of (normal paraffin, isoparaffin, aromatics, and naphthenes )[2].as it is known that light naphtha derived from crude oil that contains many types of hydrocarbons from different families, the most common hydrocarbons types in petroleum fraction (paraffin, naphthene, and aromatic)[3]. zeolite is a porous media and consists of crystalline aluminosilicates with high surface area and property of molecular sieving[4]. the 5a zeolite has been generally utilized as an adsorbent for separating n-paraffins from oil feedstocks. adsorption process dependent on 5a zeolite displays predominance in improving the usage proficiency of naphtha[5]. separation of various group composition in naphtha through the adsorption procedure utilizing zeolites 5a has pulled in extensive enthusiasm from researchers[6], [7]. zeolite 5a compound have lta (linde type a) cross section structures with ca cations[8]. t orr spon n t r m ns on 3d nn ls w t m t r o 5 1 w s tw n t s z o l n r and branched alkanes[9], [10]specify good shape selectivity in the separation of hydrocarbons. the equilibrium of adsorption [11], [12]and kinetics[13],[14]of linear paraffins by using zeolite, 5a compounds have drawn in much researches attention. c5−c6 range n-paraffin separation, joined with the process of isomerization, was used in the formation of high-octane gasoline[15]. in 2002, uop (universal oil products) built up a simulated moving bed technique [16],[17]utilizing molecular sieve 5a compounds as the adsorbent and normal pentane as the desorbent to separate linear paraffin from naphtha. the fixed bed adsorption process was built up by east china university of science and technology, it is known as molecular sieve fixed-bed adsorption (msfa) technology by using zeolite 5a as adsorbent and nitrogen as a desorbent[18],[19].in any case, the majority of the examinations on the normal paraffin separation simply focus on the adsorption range of new zeolite 5a, which differs after the adsorption/desorption cycles (regeneration). activated carbon is solids adsorbent in the separation of hydrocarbons that can create distinctive values of hydrophobicity, as indicated by oxygenated group on the surface; this feature supports organic compound adsorption (aliphatic) with low molecular weight that might be available in the air, increasing its pollution concentrations[20]. https://doi.org/10.31699/ijcpe.2019.4.5 a. n. hammadi and i. k. shakir b / iraqi journal of chemical and petroleum engineering 20,4 (2019) 27 33 82 as a porous material, activated carbon has a high surface area and pore volume, which makes it a decent adsorbent in the two gas and liquid phase [21]. there is much research revealed in the writing about the adsorption of the volatile organic compound on activated carbons[22], [23] . among these compounds is hexane (c6h14), which is a non-polar compound of a direct aliphatic chain and builds up the cooperation of a dispersive kind with the adsorbent. in this project, we studied the adsorption selectivity of zeolite (5a) and compared this process with another adsorbent (activated carbon) by using light naphtha as a feedstock for this process because light naphtha contains multicomponent of hydrocarbons with a wide range of diameter sizes. 2experimental work 2.1. materials zeolite (5a) purchased from local market produced by (bdh) chemical ltd pool england, extrudate (60-80 mesh). activated carbon purchased from the local market. 2.2. physical properties of zeolite (5a) the physical tests achieved at petroleum research and development center as shown in table 1. table 1. physical properties of molecular sieve (5a) test name result bet surface area 581.4885 m²/g bulk density 0.5848 g/cm³ crushing strength 6.3198 n/mm pore volume 0.354553 cm³/g pore size 5å 2.3. xrf for zeolite 5(a) xrf test was done at the university of baghdad – college of science department of geology. table 2 shows the chemical composition of (5a) molecular sieve. table 2. chemical composition of zeolite (5a) component sio2 al2o3 na2o cao sio2 weight % 36.89 24.56 2.190 12.29 36.89 sio2/al2o3 2.54890 2.4. activated carbon test result table 3 shows the chemical composition and physical properties of purchased activated carbon. table 3. chemical composition and physical properties of activated carbon parameters units report value iodine number mg/gm 1027 moisture % 4.86 ash % 4.63 apparent density gm/ml 0.52 ph 9.2 over size % 4.12 under size % 2.69 ball-pan hardness % 99.38 surface area m 2 /g 800 pore volume cm 3 /g 0.676 2.5. feedstock hydrogenated light naphtha supplied from al-dura refinery. table 4.shows the chemical composition of light naphtha the test achieved at petroleum research and development center by gas chromatography according to astm (d 2887-02). table 4. shows chemical composition of hydrogenated light naphtha hydrocarbon name wt. % n-paraffin name wt. % n-paraffin 47.525 c4 (n-butane) 0.06585 isoparaffin 32.902 c5 (npentane) 24.15975 naphthene 19.44 c6 (n-hexane) 19.42429 aromatics 0.133 c7 (nheptane) 3.71383 c8 (n-octane) 0.16128 2.6. adsorbents activation (5a) molecular sieve sample was activated at (400 o c) for four hours while activated carbon was heated at (200 o c) for (90 min) by using the electric furnace and transmitted after 24 hours to plastic cans with silica gel bags to keep the adsorbents dry. 2.7. experiments experiments were performed in the vapor phase by pumping (5 ml/min) of light naphtha from the bottom of a fixed bed column and passed through (100 gram) of adsorbent material. the temperature of the experiment was 180 °c according to many other experiments on adsorption behavior of light naphtha on zeolite (5a). the fixed bed stainless steel column are with (440 mm) length and (38.1 mm) inside diameter (500 ml). the stainless-steel column was followed by stainless steel condenser with an outside diameter (50 mm) and length (200mm) fig. 1 shows flowchart for the adsorption process. the pressure of experiments was (1.6 bar). time was set to zero when the pump began to work and record when the first drop appeared. a. n. hammadi and i. k. shakir b / iraqi journal of chemical and petroleum engineering 20,4 (2019) 27 33 82 the samples were collected at dark glass collectors taken at every fixed time interval and the samples were analyzed by gas chromatography device to measure the weight percentage of hydrocarbons components. the adsorption capacity was calculated according to the equation (1)[24]. ( ) (1) where, q = adsorption capacity, (g adsorbate /gadsorbent). cº = inlet concentration of adsorbate, (g/ml). ci = outlet concentration adsorbate, (g/ml). m = mass of adsorbent, (gm) q = volumetric flow rate, (ml/min). t = adsorption time, (min). fig. 1. flow chart for adsorption separation process: 1naphtha container; 2fuel pump; 3gate valve; 4flow meter; 5heater tape around the stainless-steel pipe; 6fixed bed stainless steel column with heating jacket; 7 pressure gauge; 8needle valve; 9condenser; 10 sample collector. 3results and discussion 3.1. adsorption behavior of hydrocarbons on zeolite (5a) the hydrocarbons in light naphtha majorly consist of (normal paraffin, isoparaffin, naphthene and aromatic) different group of hydrocarbons can be separated by the zeolites through adsorption shape selectivity. normal paraffins with straight long chains have a smaller footprint than those of iso-paraffins, cyclanes, and aromatics. the essential channels of zeolites a are 8-membered rings. at the point when the cations are exchanged by ca 2+ , the channel diameter is ∼5.1 å. according to the quantum chemistry calculation, the m t rs o norm l p r ns r n t r n o 4 8−5 0 å w l t m t rs r n t r n o 6 1−6 6 å or iso-p r ns n 6 7−7 4 å or y l n s n rom t s [25]. when light naphtha entered at vapor phase to a fixed bed column. normal paraffin adsorbed in the microspores of zeolite (5a). the s shape of breakthrough curve fig. 2 shows that the weight % of normal paraffin decreased while other components of hydrocarbon increased. the decrease in weight percentage of normal paraffin belongs to the suitable diameter sizes for normal paraffin components to enter (5a) zeolite pores, on the other side the isoparaffin, naphthenes, and aromatics stayed in the stream because the diameter of the size for these hydrocarbons is larger than the pore size of (5a) zeolite[26]. fig. 2. adsorption breakthrough curve of hydrocarbons separation using zeolite (5a) the percentage removal of normal paraffin at the beginning of the adsorption process (first sample of nonadsorbed components 4 ml) reached to 92 % and weight % of isoparaffin increased by 92 % compared to the weight percentage of the inlet. on the other hand the isoparaffins behave like an inert on zeolite (5a)[27]. naphthene weight percentage increased by 69 % while aromatic increased by 64 % compared to inlet weight percentage. the increase in the weight percentage of isoparaffin, naphthenes and aromatics may depend on the inlet concentration of these types of hydrocarbons. adsorption capacity will decrease as time passed until equilibrium (saturation) take place where qmax for total normal paraffin was 13.16 g/100g-adsorbent. the results partly agree with previous studies with single hydrocarbon at the very dilute concentration[28]which proved that the adsorption of hydrocarbon mixture strongly depends on the temperature of the experiment and the inlet composition. whereas the earliest time of saturation belongs to the high concentration of normal paraffin in the feed (47.525 %). -0.5 0 0.5 1 1.5 2 2.5 0 5 10 15 20 c /c º time (min) nparaffin isoparaffin naphthene aromatic a. n. hammadi and i. k. shakir b / iraqi journal of chemical and petroleum engineering 20,4 (2019) 27 33 03 normal paraffins with low carbon numbers that occupy zeolite 5a compound micropores can be partially interchanged with larger carbon numbers of normal paraffins. the roll-up phenomenon[29]can be noticed in the lowcarbon-number normal paraffin adsorption breakthrough curves as shown in fig. 3. the breakthrough curve of normal paraffin components on zeolite (5a) fig. 3. adsorption breakthrough curve of normal paraffins contents on zeolite (5a) the percentage removal of normal butane c4 at the beginning of the adsorption process (first sample of nonadsorbed components 4 ml) reached to 81.7 %, while normal pentane c5 reached to 86.8 %, normal hexane percentage removal was 98 %, normal heptane 99 % and normal octane percentage removal was 85 %, from these results we notice that highest weight % components c5, c6 and c7 will be preferred in the adsorption due to their high concentration at the inlet feed of light naphtha. in addition, we noticed form adsorption breakthrough curve that the components with a large number of carbon atoms preferred in this type of separation this agree with yang et al.[29]. 3.2. adsorption behavior of hydrocarbons on activated carbon due to the high surface area and the wide range of pores size distribution of activated carbon, non-polar molecules of a certain volume and molecular weight such as hydrocarbons have a strong affinity to activated carbon. the variation in affinity includes activated carbon being an appropriate adsorbent when separating or purifying the gas phase [30]. in spite limit use of activated carbon in the separation of hydrocarbons mixture. we notice that activated carbon generally adsorbed the naphthenes and aromatics from light naphtha feed when entered fixed bed column so there are increasing in weight percentage of isoparaffin and normal paraffin as shown in fig. 4. fig. 4. adsorption breakthrough curve of hydrocarbons separation using activated carbon at the beginning of the adsorption process (first sample of nonadsorbed components 4ml), we notice that isoparaffin and normal paraffin increased by 23 % compared to the inlet concentration. from the other side, there is a decrease in weight % of naphthenes and aromatics comparing to inlet weight percentage. the percentage removal of naphthenes reached to 95 % while the aromatics reached to 100 % whereas the inlet concentration of aromatic increased a little bit (0.133%) compared to other types of hydrocarbons. the separation behavior belongs to the large pores size compared to the zeolite (5a) which allowed for hydrocarbons that have large diameter sizes to enter pores of activated carbon. this may agree with lillo-ródenas et al. who referred to the percentage removal of hydrocarbons may also rely on porosity and the surface chemistry of the adsorbent used such as surface functional groups[31]. this adsorption behavior will continue until equilibrium (saturation) take place. for more details about normal paraffin concentration, we must discuss the results of normal paraffins contents. we noticed at the beginning of the process (first sample of non – adsorbed components 4ml) the weight % of c6, c7and c8 decreased while the c4 and c5 increased. the weight % of normal butane c4 increased by 281 % while normal pentane c5 increased by 139 % this increase refers to the normal paraffin which has a large number of carbon atoms preferred in the separation process although the high concentration of c5 normal pentane in the feedstock. in addition, there is a decrease in weight % compared to inlet concentration for normal hexane c6 by 97.5 %. while normal heptane percentage removal was 99.7 % and normal octane was 100 %. fig. 5 shows adsorption breakthrough curve for normal paraffin components. -0.2 0 0.2 0.4 0.6 0.8 1 1.2 0 5 10 15 20 c /c º time (min) c4 c5 c6 c7 c8 -0.5 0 0.5 1 1.5 0 5 10 15 20 c /c º time (min) n-paraffin isoparaffin naphthene aromatic a. n. hammadi and i. k. shakir b / iraqi journal of chemical and petroleum engineering 20,4 (2019) 27 33 03 fig. 5. adsorption breakthrough curve for normal paraffin components the adsorption behavior of light naphtha hydrocarbons may agree with villacañas et al. that is referred to that the activated carbon surface chemistry plays a main role in removing components of hydrocarbons as it impacts both electrostatic and dispersive interactions between adsorbents and adsorbates, which are essentially interactions in the form of van der waals[32]. the adsorption capacity calculated according to equation (1) for both naphthenes and aromatics where qmax was 5.55 g/100g adsorbent and 0.0399 g/100g adsorbent for naphthenes and aromatics respectively. 4conclusions the study of hydrocarbon adsorption of light naphtha components at vapor phase in fixed bed adsorber refers to the ability to adsorb n-paraffin from light naphtha by (92 %) at process beginning and increases the percentage of (isoparaffin, naphthene and aromatic) because the components of normal paraffin has size diameter smaller than pores of zeolite (5a). from the other hand activated carbon which has a wide range of pore size generally adsorb naphthenes and aromatics by (95%) and (100 %) respectively, while the percentage of total paraffins increased (isoparaffin and normal paraffins). for more details, we noticed that the normal paraffins components c4 normal butane and c5 normal pentane increased while other components c6 (normal hexane), c7 (normal heptane) and c8 (normal octane) decreased. this indicates that adsorption behavior strongly depends on the inlet concentration and the structure of adsorbents. references [1] g. p. company and b. division, petrochemical. 2000. [2] e. meneses-ruiz, g. c. laredo, j. castillo, and j. o. m rroqu n ―comp r son o r nt mol ul r s v s for the liquid phase separation of linear and branched lk n s ‖ fuel process. technol., vol. 124, pp. 258– 266, 2014. [3] a.-h. abdul-karim mohammed, h. g. attiya, and h. ul k l q k u r ―t r l t ons ps tw n the physical and chemical properties of narrow fractions distilled from mixed kirkuk and sharkibaghdad crud o ls‖ ijcpe, vol. 9, no. 2, pp. 1-8, jun. 2008. [4] n s m j n j t m j ―stu y t performance of nanozeolite naa on co 2 gas upt k ‖ iraqi j. chem. pet. eng., vol. 18, no. 2, pp. 57–67, 2017. [5] j c o n b x s n ―opt m z ut l z t on o naphtha: liquid adsorption separation of linear paraffins in naphtha with n-p nt n s t sor nt ‖ energy sources, part a recover. util. environ. eff., vol. 35, no. 3, pp. 235–245, 2013. [6] a. c. silva, f. a. da silva, and e. rodrigues, ―s p r t on o n / so p r ns y ps ‖ vol 20 pp 97–110, 2000. [7] j c l u b x s n n j h don ― n lys s o nc4 ∼ n-c10 mixtures in 5a molecular sieves using ias theory with multi-s t l n mu r sot rms ‖ adsorption, vol. 15, no. 5–6, pp. 423–428, 2009. [8] f. tomás-alonso, l. a. angosto olmos, and m. a. muñ s v l ―s l t v s p r t on o norm l paraffins from slack wax using the molecular sieve sorpt on t n qu ‖ sep. sci. technol., vol. 39, no. 7, pp. 1577–1593, 2004. [9] c e goun r s j w n c flou s ―r t on l design of shape selective separation and catalysis — ii : m t m t l mo l n omput t on l stu s ‖ vol. 61, pp. 7949–7962, 2006. [10] j. bacon et al. ―book r v ws ‖ philosophia (mendoza)., vol. 5, no. 3, pp. 319–384, 1975. [11] j c s lv n e ro r u s ― mult s t langmuir model applied to the interpretation of sorption of n -p r ns n 5 z ol t ‖ ind. eng. chem. res., vol. 38, no. 6, pp. 2434–2438, 1999. [12] m. j. ahmed, a. h. a. k. mohammed, and a. h k um ―pr t on o mult ompon nt equilibrium isotherms for light hydrocarbons sorpt on on 5 z ol t ‖ fluid phase equilib., vol. 313, pp. 165–170, 2012. [13] a. g. stepanov, t. o. shegai, m. v luzgin, and h jo ―p hysic l j ourn l e comp r son o the dynamics of n-hexane in zsm-5 and 5a zeolite stru tur s ‖ vol 61 pp 57–61, 2003. [14] i. de recherches, a. einstein, and c. krause, ―d us v t s o n -alkanes in 5a zeolite measured by neutron spin echo , pulsed-field gradient nmr , n z ro l n t column t n qu s ‖ pp 403–407, 2005. [15] p e r d v s ―un t st t s p t nt 19 ‖ no 19, 1991. [16] mcculloch, beth, and james r. lansbarkis. "process for separating normal olefins from nonnormal olefins." u.s. patent no. 5,276,246. 4 jan. 1994. [17] a. c. wilson, m. a. us, h. zhang, and s. b. gl z r ― 12 un t st t s p t nt ‖ vol 2 no 12 2016. -1 0 1 2 3 4 5 0 5 10 15 20 c /c º time (min) c4 c5 c6 c7 c8 https://www.sciencedirect.com/science/article/pii/s0378382014001040 https://www.sciencedirect.com/science/article/pii/s0378382014001040 https://www.sciencedirect.com/science/article/pii/s0378382014001040 https://www.sciencedirect.com/science/article/pii/s0378382014001040 https://www.sciencedirect.com/science/article/pii/s0378382014001040 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/432 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/432 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/432 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/432 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/432 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/432 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/203 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/203 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/203 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/203 https://www.tandfonline.com/doi/abs/10.1080/15567036.2010.509088 https://www.tandfonline.com/doi/abs/10.1080/15567036.2010.509088 https://www.tandfonline.com/doi/abs/10.1080/15567036.2010.509088 https://www.tandfonline.com/doi/abs/10.1080/15567036.2010.509088 https://www.tandfonline.com/doi/abs/10.1080/15567036.2010.509088 https://www.sciencedirect.com/science/article/pii/s1383586600000642 https://www.sciencedirect.com/science/article/pii/s1383586600000642 https://www.sciencedirect.com/science/article/pii/s1383586600000642 https://link.springer.com/article/10.1007/s10450-009-9191-8 https://link.springer.com/article/10.1007/s10450-009-9191-8 https://link.springer.com/article/10.1007/s10450-009-9191-8 https://link.springer.com/article/10.1007/s10450-009-9191-8 https://www.tandfonline.com/doi/abs/10.1081/ss-120030787 https://www.tandfonline.com/doi/abs/10.1081/ss-120030787 https://www.tandfonline.com/doi/abs/10.1081/ss-120030787 https://www.tandfonline.com/doi/abs/10.1081/ss-120030787 https://www.tandfonline.com/doi/abs/10.1081/ss-120030787 https://www.sciencedirect.com/science/article/pii/s0009250906005811 https://www.sciencedirect.com/science/article/pii/s0009250906005811 https://www.sciencedirect.com/science/article/pii/s0009250906005811 https://www.sciencedirect.com/science/article/pii/s0009250906005811 https://www.journals.uchicago.edu/doi/abs/10.1086/349659?journalcode=isis https://www.journals.uchicago.edu/doi/abs/10.1086/349659?journalcode=isis https://pubs.acs.org/doi/abs/10.1021/ie980696t https://pubs.acs.org/doi/abs/10.1021/ie980696t https://pubs.acs.org/doi/abs/10.1021/ie980696t https://pubs.acs.org/doi/abs/10.1021/ie980696t https://www.sciencedirect.com/science/article/abs/pii/s0378381211004870 https://www.sciencedirect.com/science/article/abs/pii/s0378381211004870 https://www.sciencedirect.com/science/article/abs/pii/s0378381211004870 https://www.sciencedirect.com/science/article/abs/pii/s0378381211004870 https://www.sciencedirect.com/science/article/abs/pii/s0378381211004870 https://link.springer.com/article/10.1140/epje/i2003-10037-3 https://link.springer.com/article/10.1140/epje/i2003-10037-3 https://link.springer.com/article/10.1140/epje/i2003-10037-3 https://link.springer.com/article/10.1140/epje/i2003-10037-3 https://link.springer.com/article/10.1140/epje/i2003-10037-3 https://link.springer.com/article/10.1140/epje/i2003-10037-3 https://link.springer.com/article/10.1140/epje/i2003-10037-3 https://link.springer.com/article/10.1140/epje/i2003-10037-3 https://link.springer.com/article/10.1140/epje/i2003-10037-3 https://patents.google.com/patent/us5032380a/en https://patents.google.com/patent/us5032380a/en https://patents.google.com/patent/us5276246a/en https://patents.google.com/patent/us5276246a/en https://patents.google.com/patent/us5276246a/en https://patents.google.com/patent/us5276246a/en a. n. hammadi and i. k. shakir b / iraqi journal of chemical and petroleum engineering 20,4 (2019) 27 33 08 [18] j l u n b s n ―opt m z n n p t ut l z t on s on mol ul r s l m n m nt ‖ pet. sci. technol., vol. 25, no. 11, pp. 1465–1471, 2007. [19] j l u n b s n ― sorpt on s p r t on n use of normal and iso-hydrocarbons in hydrogenated cok n g sol n ‖ vol 25 no 8 pp 975–978, 2009. [20] l l s l u n j l u ―sur mo t on of coconut shell based activated carbon for the mprov m nt o y rop o voc r mov l ‖ j. hazard. mater., vol. 192, no. 2, pp. 683–690, 2011. [21] d h rn l g r l o n j c rlos ―stu y o hexane adsorption on activated carbons with d r n s n t r sur c m stry ‖ pp 1–13, 2018. [22] x. yao, j. liu, g. gong, y. jiang, and q. xie, ―pr p r t on n mo t on o t v t r on or benzene adsorption by steam activation in the pr s n o koh ‖ int. j. min. sci. technol., vol. 23, no. 3, pp. 395–401, 2013. [23] s. tazibet, y. boucheffa, and p. lodewyckx, ―h t tr tm nt t on t t xtur l y rop o and adsorptive properties of activated carbons o t n rom ol v w st ‖ microporous mesoporous mater., vol. 170, pp. 293–298, 2013. [24] a. h. a.k. mohammed and m. mehdi abdulr m ― sorpt on o btx rom t rom r orm t y 13x mol ul r s v ‖ ijcpe, vol. 9, no. 4, pp. 13-20, dec. 2008. [25] c e goun r s n æ g somorj ―s r en n s or s p s l t v ty ‖ pp 234–241, 2009. [26] m. feng, x. zhou, w. hu, w. wang, and c. li, ―improv s p r t on n ut l z t on o l t n p t sto k y sorpt on pro ss ‖ adsorpt. sci. technol., 2018. [27] m. j. ahmed, a. h. a. k. mohammed, and a. h k um ―mo l n o br kt rou curv s for adsorption of propane, n-butane, and iso-butane m xtur on 5 mol ul r s v z ol t ‖ transp. porous media, vol. 86, no. 1, pp. 215–228, 2011. [28] g. c. laredo, e. meneses, j. castillo, j. o. marroquin, and f. jiménez-cruz ― sorpt on equilibrium and kinetics of branched octane isomers on a polyvinylidene chloride-based carbon molecular s v ‖ energy and fuels, vol. 22, no. 4, pp. 2641– 2648, 2008. [29] r. yang, gas separation by adsorption processes, vol. 2. 1987. [30] y. j. tham, p. a. latif, a. m. abdullah, a. shamala-devi, and y. h. taufiq-y p ―p r orm n s of toluene removal by activated carbon derived from ur n s ll ‖ bioresour. technol., vol. 102, no. 2, pp. 724–728, 2011. [31] m. a. lillo-ródenas, d. cazorla-amorós, and a. linares-sol no ―b v our o t v t r ons with different pore size distributions and surface oxygen groups for benzene and toluene adsorption at low conc ntr t ons ‖ carbon n. y., vol. 43, no. 8, pp. 1758–1767, 2005. [32] f. villacañas, m. f. r. pereira, j. j. m. órfão, n j l f u r o ― sorpt on o s mpl rom t ompoun s on t v t r ons ‖ j. colloid interface sci., vol. 293, no. 1, pp. 128–136, 2006. https://www.tandfonline.com/doi/abs/10.1080/10916460600695314 https://www.tandfonline.com/doi/abs/10.1080/10916460600695314 https://www.tandfonline.com/doi/abs/10.1080/10916460600695314 https://www.tandfonline.com/doi/abs/10.1080/10916460600695314 https://pubs.acs.org/doi/abs/10.1021/ef800979v https://pubs.acs.org/doi/abs/10.1021/ef800979v https://pubs.acs.org/doi/abs/10.1021/ef800979v https://www.sciencedirect.com/science/article/abs/pii/s0304389411007230 https://www.sciencedirect.com/science/article/abs/pii/s0304389411007230 https://www.sciencedirect.com/science/article/abs/pii/s0304389411007230 https://www.sciencedirect.com/science/article/abs/pii/s0304389411007230 https://www.mdpi.com/1420-3049/23/2/476 https://www.mdpi.com/1420-3049/23/2/476 https://www.mdpi.com/1420-3049/23/2/476 https://www.mdpi.com/1420-3049/23/2/476 https://www.sciencedirect.com/science/article/pii/s2095268613000839 https://www.sciencedirect.com/science/article/pii/s2095268613000839 https://www.sciencedirect.com/science/article/pii/s2095268613000839 https://www.sciencedirect.com/science/article/pii/s2095268613000839 https://www.sciencedirect.com/science/article/pii/s2095268613000839 https://www.sciencedirect.com/science/article/abs/pii/s138718111200697x https://www.sciencedirect.com/science/article/abs/pii/s138718111200697x https://www.sciencedirect.com/science/article/abs/pii/s138718111200697x https://www.sciencedirect.com/science/article/abs/pii/s138718111200697x https://www.sciencedirect.com/science/article/abs/pii/s138718111200697x http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/450 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/450 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/450 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/450 https://link.springer.com/article/10.1007/s10562-009-0155-0 https://link.springer.com/article/10.1007/s10562-009-0155-0 https://journals.sagepub.com/doi/full/10.1177/0263617417721571 https://journals.sagepub.com/doi/full/10.1177/0263617417721571 https://journals.sagepub.com/doi/full/10.1177/0263617417721571 https://journals.sagepub.com/doi/full/10.1177/0263617417721571 https://link.springer.com/article/10.1007/s11242-010-9617-5 https://link.springer.com/article/10.1007/s11242-010-9617-5 https://link.springer.com/article/10.1007/s11242-010-9617-5 https://link.springer.com/article/10.1007/s11242-010-9617-5 https://link.springer.com/article/10.1007/s11242-010-9617-5 https://pubs.acs.org/doi/abs/10.1021/ef7006408 https://pubs.acs.org/doi/abs/10.1021/ef7006408 https://pubs.acs.org/doi/abs/10.1021/ef7006408 https://pubs.acs.org/doi/abs/10.1021/ef7006408 https://pubs.acs.org/doi/abs/10.1021/ef7006408 https://pubs.acs.org/doi/abs/10.1021/ef7006408 https://www.sciencedirect.com/science/article/pii/s0960852410014495 https://www.sciencedirect.com/science/article/pii/s0960852410014495 https://www.sciencedirect.com/science/article/pii/s0960852410014495 https://www.sciencedirect.com/science/article/pii/s0960852410014495 https://www.sciencedirect.com/science/article/pii/s0960852410014495 https://www.sciencedirect.com/science/article/abs/pii/s0008622305001326 https://www.sciencedirect.com/science/article/abs/pii/s0008622305001326 https://www.sciencedirect.com/science/article/abs/pii/s0008622305001326 https://www.sciencedirect.com/science/article/abs/pii/s0008622305001326 https://www.sciencedirect.com/science/article/abs/pii/s0008622305001326 https://www.sciencedirect.com/science/article/abs/pii/s0008622305001326 https://www.sciencedirect.com/science/article/abs/pii/s0021979705006922 https://www.sciencedirect.com/science/article/abs/pii/s0021979705006922 https://www.sciencedirect.com/science/article/abs/pii/s0021979705006922 https://www.sciencedirect.com/science/article/abs/pii/s0021979705006922 a. n. hammadi and i. k. shakir b / iraqi journal of chemical and petroleum engineering 20,4 (2019) 27 33 00 أ( والكربون المنشط5امتزاز مركبات النفثا الخفيفة باستخدام الزيواليت )سموك 2وابتهال كريم شاكر 1احمد نجيب بغداد العراق-شركة توزيع المنتجات النفطية-وزارة النفط1 كمية الهندسة-جممعة بغداد2 الخالصة النفثا الخفيفية هي احد نواتج برج التقطير في المصافي النفطية تستخدم كمادة خام النتاج البنزين . المركبات ) البرافينات الخطية , البرافينات المتفرعة , النفثينات و المركبات االروماتية( . في الرئيسية لمنفثا الخفيفة هي انكستروم( لغرض فصل البارافينات الخطية 5مسامات واحد ) ( بحجم 5aهذا البحث تم استخدام الزيواليت ) من النفثا الخفيفة , ويعود هذا الى الحجم المناسب لممسامات في هذه العممية ومقارنة سموك االمتزاز مع الكربون المنشط والذي يحتوي عمى مدى واسع من حجوم المسامات )مايكروبوروس و ميزوبوروس( باالضافة السطحية العالية. العممية تمت بالنظام المستمرباستخدام ) مفاعل الحشوه الثابتة( في الطور الى المساحة غم وزن 100بار و 1,1م و الضغط 180oمل/ دقيقة( , ودرجة الحرارة 5البخاري و بظروف ثابتة بجريان ) من وقود النفثا الخفيفة (c4 – c8)( قام بفصل المركبات البرافينية الخطية 5aالمادة الممتزة. المنخل الجزيئي ) %( في بداية العممية. اما الكربون المنشط قام بفصل المركبات النفثينية 62,31بأعمى نسبة ازالة وصمت الى ) %( لممركبات االروماتية في بداية 100%( لمنفثينات و ) 6553واالروماتية بأعمى نسبة ازالة وصمت الى ) الف في سموك االمتزاز الفيزياوي وتاثير حجم المسامات عمى العممية . عممية الفصل. هذه الدراسة تبين االخت أ( 5 الكربون المنشط 5 عممية االمتزاز. 5: النفثا الخفيفة 5 الزيواليت )الدالةالكممات dr wadood _mag_.doc ijcpe vol.8 no.4 (december 2007) 45 iraqi journal of chemical and petroleum engineering vol.8 no.4 (december 2007) 45-52 issn: 1997 -4884 catalytic wet air oxidation of phenol in a trickle bed reactor wadood t. mohammed, sama m. abdullah, and atheer m. ghalib chemical engineering department college of engineering university of baghdad iraq abstract catalytic wet air oxidation of aqueous phenol solution was studied in a pilot plant trickle bed reactor using copper oxide catalyst supported on alumina and silica. catalysts were prepared by impregnating method. effect of feed solution ph (5.9, 7.3, and 9.2), gas flow rate (20%, 50%, 80%, and 100%), whsv (1, 2, and 3 h -1), temperature (120°c, 140°c, and 160°c), oxygen partial pressure (6, 9, 12 bar), and initial phenol concentration (1, 2, and 4 g/l).generally, the performance of the catalysts was better when the ph of feed solution was increased. the catalysts deactivation is related to the dissolution of the metal oxides from the catalyst surface due to the acidic conditions. phenol oxidation reaction was strongly affected by whsv, temperature, oxygen partial pressure, and initial phenol concentration. while gas flow rate had a marginal effect. keywords: oxidation of phenol, trickle bed reactor. introduction disposal of wastewater is acquiring increasing importance all over the world; due to the progressively more restrictive environmental constrains (1). phenol commonly appears in aqueous effluents from sources such as petrochemical, chemical, and pharmaceutical industries (2). the importance of phenol in water pollution stems from their extreme toxicity to the aquatic life and resistance to biodegradation. phenol imparts a strong disagreeable odor and taste to water even in very small concentration (3). moreover, phenol and its derivatives are powerful bactericides which prevents them from being treated in classical sewage processing plants even at concentrations as low as 50 g/l (4).as one of wastewater abatement technologies, wet air oxidation (wao) emerges recently and non-biodegradable industrial effluents (5). in wao, air or pure oxygen is used to oxidize refractory pollutions either dissolved or suspended in water (6). however, wet oxidation of wastewater without the aid of catalyst, is usually conducted at very high temperature and pressure, thus, leading to high equipment and operation costs (7). the oxidation of organic aqueous solutions over a solid catalyst has been shown to be a useful and inexpensive nonconvential treatment process(8). nevertheless, the development of a satisfa ctory catalyst for this process has been reported yet. such catalyst should be able to oxidize low concentrations in aqueous media and possess resistance to inactivation by leaching (9). unfortunately, the lack of catalysts which are active and durable under these process conditions has largely prevented cwo from being implemented for environmental remediation (10).supported copper oxide catalysts have frequently been tested for the wet oxidation of organic compounds (11). despite the fact that copper-based catalysts are very active in batch processes, tests using continuous reactors reveal that there is a substantial loss of activity due to the dissolution of the catalytic species in the acidic reactive medium (1). these apparently contradictory results can be explained by the different duration of the tests. for instance, in continuous reactors, the tests usually runs for several days, while, in batch experiments, the reaction only occurs for a few hours, which is too short a period for finding significant activity changes (10) . experimental work material and catalyst preparation the phenol used as reagent was purchased from griffin. high purity synthetic air was used as oxidant. university of baghdad college of engineering iraqi journal of chemical and petroleum engineering catalytic wet air oxidation of phenol in a trickle bed reactor ijcpe vol.8 no.4 (december 2007) 46 deionized water was used to prepare catalyst and different aqueous solutions. glass balls were used in the tests with inert material. ?-alumina or silica were used as supports for the copper. copper nitrate from fluka was used as active component. zinc nitrate, and nickel nitrate from bdh chemicals ltd. were used as promoters. copper-based catalyst was prepared using ?-alumina as support. the alumina, which was supplied as spheres of 2.5 mm diameter, was dried for 4 h at 110°c. the catalyst was made with a copper oxide loading of 10% and prepared by the pore volume impregnation method using aqueous solutions of copper nitrate (26 g copper nitrate dissolved in 45 ml hot deionized water) for impregnating the support. later, the catalyst was dried at 110°c overnight, followed by calcining at 400°c for 8 h with air. the same procedure was followed to prepare one catalyst supported over silica, also with a copper oxide loading of 10%, and two catalysts supported over ?-alumina with a copper oxide loading of 10%, and 2% of zinc oxide and nickel oxide. table 1 lists the main physical characteristics of different catalysts prepared and supports used. table 1. the main physical characteristics of different catalysts prepared and supports used. experimental set-up and procedure the continuous oxidation of phenol was carried out in a packed bed reactor. the fixed bed reactor consists of a ss-316 tubular reactor, 80 cm long and 1.9 cm inner diameter and controlled automatically by for sections of 15 cm height steel-jacket heaters. independent inlet systems for gas and liquid feed allow working at various liquid to gas flow rate ratios. the liquid feed is stored in a feed tank, which is connected to a high-pressure metering pump (dosing pump) that can dispense flow rates between 0 and 15 ml/min at constant pressure. the air oxidant comes from a high pressure cylinder equipped with a pressure controller to maintain the operating pressure constant. a flow-meter coupled with a high precision valve is used to measure and control the gas flow rate. the liquid and gas streams are mixed and then entered to the reactor at the required temperature. the mixture flows along the bed packed with 85 cm3 (30 cm height) of the catalyst enclosed between two layers of inert material (also a flexible grid put at the top and bottom of the reactor to prevent movement of particles).the exited solution goes to a liquid-gas separation and sampling system, regularly, liquid samples were withdrawn for analysis. figure 1 illustrated the experimental setup. to verify that only the catalyst causes the oxidation of the phenol, two tests were made using an inert material (silica and ?-alumina). in both cases, the phenol removal was negligible, less than 0.1 %, which falls within the experimental error. fig. 1, experimental setup ph-adjustment the ph of 4 g/l phenol solution is slightly acid, about 5.9. however, for both tests of ph 7.3 and 9.2, the feed solution was adjusted by adding sodium hydroxide solution. to measure ph of the solution oakion ph2100 series was used. the procedure was summarized as following: 1. ph meter was calibrated previous to use by using buffer solutions. 2. measuring the ph of 4 g/l phenol solution. 3. adding particular quantities of naoh solution to the 4 g/l phenol solution according to the titration method to obtain solutions of ph 7.3 and 9.2. products analysis to analysis phenol concentration in the outlet samples, shimadzu model uv-160a ultraviolet/visible spectrophotometer was used. the intermediate wadood t. mohammed et al ijcpe vol.8 no.4 (december 2007) 47 compounds are determined by gas liquid chromatography analysis (pye unicam). the apparatus consists of a stainless steel capillary column with 5 m long and 0.25 mm inside diameter (se– 30) name type, packing with silica; and column temperature programming from 343 to 423 k for c2 to c6 analysis. the carrier gas is nitrogen flowing at 12 cm3/min. phenol conversion, xph, will be used as the main parameter for comparing the results, xph is defined as: [ ] [ ] [ ]in outin ph ph phph x − = (1) results and discussion determination of the most active catalyst figure 2 presents a comparison of the activities of the prepared catalysts. all four catalysts show similar behavior. the necessary time to reach this steady state conversion (induction period) is smaller for all catalysts. this is due to the high temperature and oxygen partial pressure used in this study, in addition to the using of packed bed continuous reactor. also, it can be seen that phenol conversion for these catalysts started from low values after that reaches to high values. that observed difference in phenol conversion can be explained by the effect of sequence of initial exposure of the catalyst to the reactant. the catalyst can be ranked as follows in terms of activity in phenol oxidation. cat.4 > cat.3 > cat.1 > cat.2 20 30 40 50 60 70 80 90 100 0 50 100 150 200 250 300 350 time, min x p h ( % ) cat.1 cat.2 cat.3 cat.4 fig. 2, comparison of the activities of the catalyst. reaction conditions: feed solution ph=5.9, s.e. = 50 %, whsv= 2h-1, t=140oc, po2= 6 bar and c ph= 4 g/l the evolution of the catalytic activity for cat.1, cat.3 and cat.4 that appear in the figure 2 has been related to the presence of two different species of copper attached to the alumina surfaces. the first would be more active but also less stable in the reaction conditions. on the other hand, the second species would be more stable and responsible for the residual activity of the catalyst. x ray characterization of the catalysts proved that these species are respectively "free" copper oxide and nonstochiometric copper aluminates. it is wellknown that most metal oxides, as copper oxide, dissolve in hot acidic media such as the one existing in the reactor. on the other hand, the treatment at high temperature, e.g. a calcinations temperature of 400? c, of a mixture of copper and aluminum oxides forms copper aluminates that is more resistant to the acidic medium but is less catalytically active than the "free" copper oxide. catalyst deactivation has been related to attack on the catalyst by the extremely hot acidic medium where the oxidation takes place. the acidic medium is provided by the phenol itself because it is capable of dissociating to form phenolate; however the partial oxidation products are the main cause of the total acidity of the aqueous reaction system. the intermediates in the phenol oxidation have been found to be mainly mono and dicarboxylic acids such as oxalic, acetic or formic acid. 0 2 4 6 8 10 12 14 16 18 20 0 50 100 150 200 250 300 350 time, min c u + 2 c o n c e n tr a ti o n ( pp m ) cat.1 cat.2 cat.3 cat.4 fig. 3, copper concentration profile in the reactor effluent. reaction conditions: feed solution ph=5.9, s.e. = 50 %, whsv= 2h-1, t=140oc, po2= 6 bar and cph= 4g/l. one possible reason for the catalyst deactivation could be the dissolution of the metal oxides in the acidic medium. this speculation is proved by figure 3 for the cat.1, cat.2, cat.3, and cat.4 respectively, which shows the cu +2 concentration in the outlet stream through the activity test. at first, the rate of dissolution of copper oxide rapidly increases until giving a maximum cu +2 concentration (11.8, 18.9, 8.29, and 6.4 ppm) for the catalysts cat.1, cat.2, cat.3, and cat.4 respectively. this behavior agrees with the presence of the two different species, the "free" copper oxide being easily dissolved during the first hours. the possibility that deposition of phenol condensation pro ducts on the catalyst surface causes the catalyst deactivation was rejected. this may be catalytic wet air oxidation of phenol in a trickle bed reactor ijcpe vol.8 no.4 (december 2007) 48 directly related to use of packed bed as reacting system, which its conditions (high catalyst to liquid ratio) favor the heterogeneous reactions rather than homogenous reactions, which enable the formation of polymers, due to the high contact surface. therefore, the catalyst (cat.2) was prepared using silica as support in order to find whether or not a different support for the copper oxide could improve the resistance against leaching. cat.2 shows very characteristic trends, it has a short induction period in which the phenol conversion increases until it reaches a maximum conversion. then, it losses its activity very fast and progressively approaching 23.4 %. this behavior could be explained by the existence of only "free" copper oxide linked to the silica, which is easily and continuously dissolved during the activity test. in this case, copper cannot form aluminates and all the copper loading is present as copper oxid e. thus, due to the higher activity of this species, cat.2 renders a higher peak of conversion but the leaching is substantially more important. the influence of promoter's metal oxides on the phenol oxidation reaction was studied too. these promoters (zno and nio) have the advantages of, changing the vulnerability of the copper oxide poisoning; protect the active metal against over-oxidation. although the very different sources and compositions of these catalysts make it very difficult to compare their re spective performances. effect of feed solution ph the previous results demonstrate the intrinsic relationship between the catalyst activity and feed solution ph. in order to examine the influence of the ph on the ability of catalysts to oxidize phenol, various tests at different phs were conducted for cat.2 and cat.4 figure 4 illustrates the dependence of the phenol conversion upon the feed solution ph using cat.4. where was used feed solution with phs 7.3 and 9.2 in addition to unmodified phenol solution (ph=5.9). as can be seen, the behavior of this catalyst maintains the general trends given by cat.4 regardless of the ph, so two different activity zones are observed. in the first zone (steady state zone), the catalyst shows high activity for a short period in which the phenol conversions nearly reach higher value. then after a progressive fall, the phenol forms a second zone (falling rate zone). the loss in catalytic activity can be delayed by increasing the ph but, in turn, the residual conversion lower at high basic solution. thus at ph=5.9, the residual phenol conversion is slightly higher than 41.38 % and decrease to 40 % and 37 % at phs 7.3 and 9.2 respectively. as discussed above, the two zones can be explained because of the two different copper species over the alumina surface, both with different catalytic activity. the decrease in activity occurs when the most active copper oxide dissolves. because of their characteristics, these oxides dissolve more slowly as ph increases, so the first zone is longer in the basic medium. however, the remaining conversion is also lower, which is opposite to what could be expected. a probable explanation for this lower conversion is that basic medium interferes with the catalyst during the induction perio d, giving less active catalysts. 30 40 50 60 70 80 0 50 100 150 200 250 300 350 time, min x ph (% ) ph=5.9 ph=7.3 ph=9.2 fig. 4, effect of feed solution ph on phenol oxidation. reaction conditions: type of catalyst= cat.4, s.e. = 50%, whsv=2 h -1, t=140°c, po2= 9 bar, and c ph= 4 g/l. 0 10 20 30 40 50 60 70 80 90 100 0 50 100 150 200 250 300 350 time, min x p h (% ) ph=5.9 ph=7.3 ph=9.2 fig 5, effect of feed solution ph on phenol oxidation. reaction cond.: type of catalyst= cat.2, s.e. = 50%, whsv=2 h -1, t=140°c, po2= 9 bar, and cph= 4 g/l. the influence of the feed solution ph on the catalytic activity was also tested for cat.2 at higher phs (7.3 and 9.2) in order to improve the activity or decrease the leaching of copper for this catalyst. figure 5 displays the phenol conversion profiles over cat.2 feeding these solutions at 5.9, 7.3, and 9.2. at feed ph of 7.3, the induction period almost short giving an initial conversion 98.43 %. then, the conversion goes steadily down, which indicate that this ph doesn't completely prevent the copper oxide from being dissolved. the reason for this behavior is that, wadood t. mohammed et al ijcpe vol.8 no.4 (december 2007) 49 although the inlet ph is basic, the outlet ph is still acid. the induction period nearly disappears for run in which the feed solution was fixed at ph 9.2. it should be pointed out this case has almost constant phenol conversion throughout the test; the phenol conversion is nearly 27.67 %. thus, the higher ph, the higher the remaining phenol conversion, so the inlet ph clearly affects catalyst activity. this can be explained by the different rates of dissolution of copper oxide in the aqueous solution. the solubility of any metal oxide is usually higher at low ph than at higher ph. hence, in run of ph 5.9, the rate of copper oxide dissolution should be the highest. a visual inspection at the end of the test certainly should an intense de-coloration was less important as the ph increased, which proves that a high ph prevents the leaching of copper. nonetheless, it is difficult to discern whether or not the different remaining conversion is only due to the different rate of catalyst deactivation or there is also some change in the mechanism reaction. it has been shown that phenolate ion is much more reactive than phenol in basic media so the reaction occurs faster and gives a better phenol conversion. however, both show similar reaction rates in acidic media because the phenolate concentration is very low. at high ph (i.e. ph=9.2), the phenolate form predominates in comparison with the un-dissociated phenol. therefore, the higher remaining conversion observed for experiment of ph=9.2 could also be due to the higher reactivity of the phenolic species present. 3 4 5 6 7 8 9 10 0 50 100 150 200 250 300 350 time, min p h ph = 5.9 ph = 7.3 ph = 9.2 fig. 6, evolution of the effluent ph for cat.4 at different feed solution ph. reaction conditions: s.e. = 50%, whsv=2 h -1, t=140°c, po2= 9 bar, and cph= 4 g/l. figures 6, 7 show the ph evolution of the outlet effluents produced for both cat.2 and cat.4. note that the inlet ph is 5.9, which correspond to a phenol solution of 4g/l. in general terms, the trends of ph evolution for cat.2 at different phs are the same as for cat.4 except at ph=9.2. as can be seen, the ph of the reaction effluent considerably varies throughout the test. it must be noted that, in the first zones, the phs are nearly steady around 5.66, 7.23, and 8.64, when the phenol conversion's are about 70.5 %, 74 % and 72 % respectively. likewise, in the second zones, when the phenol conversions reach to 43.67 %, 48.6 % and 52.5 %, the phs are close to 3.67, 5.56 and 6.51 respectively. in addition, the rapid fall in phenol conversion coincides with the decrease in the ph, but also with the highest leaching of copper, which proves that a good correlation can be established between them. 3 4 5 6 7 8 9 10 0 50 100 150 200 250 300 350 time, min p h ph = 5.9 ph = 7.3 ph = 9.2 fig. 7, evolution of the effluent ph for cat.2 at different feed solution ph. reaction conditions: s.e. = 50%, whsv=2 h -1, t=140°c, po2= 9 bar, and cph= 4 g/l. effect of gas flow rate figure 8 presents the influence of gas flow rate, which can be expressed as stochiometric excess (s.e), on phenol conversion. although phenol conversion appeared to be slightly sensitive to gas inlet velocity, but phenol conversions were improved when the inlet velocity increased and after that decre ase with further increasing in the gas inlet velocity. the results above show that an increasing gas flow rate to 80 % s.e. causing decreasing in the liquid hold up and liquid film thickness covered catalyst surface, and enhancing oxygen transfer to the liquid phase, and from the liquid phase to the catalyst surface, therefore lead to high conversion. but increasing s.e. to 100 % causes decreasing phenol conversion because of decreasing the spreading of the liquid film over catalyst hence wetting decrease. in addition, increasing s.e. over 80 % provides a sufficient quantity of oxygen for competitive reactions of intermediate over catalyst active sites forming undesirable compounds causing deactivation of catalyst. at high s.e. (i.e. 100 %) both p-benzoquinone and maleic acids were detected in high concentration in the brownish colored liquid effluent. catalytic wet air oxidation of phenol in a trickle bed reactor ijcpe vol.8 no.4 (december 2007) 50 also, it can be seen that when insufficient oxygen was fed, the reaction was dominated by the formation of low molecular weight carboxylic acids, which corresponds to the observed low ph. 20 30 40 50 60 70 80 0 50 100 150 200 250 300 350 time, min x p h (% ) s.e.=20% s.e.=50% s.e.=80% s.e.=100% fig. 8, effect of gas flow rate on phenol oxidation. reaction cond.: type of catalyst= cat.4, feed solution ph = 7.3, whsv = 2 h -1, t= 140oc, po2= 9 bar and cph = 4 g/l effect of whsv figure 9 presents that the liquid flow rate has a large effect on phenol conversion. so as liquid flow rate increases, phenol conversion decreases, this due to reduce the space time of reactant in the reactor (i.e. reducing the time required for phenol reaction with oxygen over the cataly st). moreover, higher liquid flow rates give greater liquid hold up which evidently decreases the contact of liquid and gas reactants at the catalyst active site, by increasing the film thickness. while at low liquid flow rate, the liquid resides in the column for a longer time, and therefore undergoes more conversion. fig. 9, effect of whsv on phenol oxidation. reaction cond.: type of catalyst= cat.4, feed solution ph = 7.3,s.e. = 80 %, t= 140oc, po2= 9 bar and cph = 4 g/l effect of temperature the general behavior is, higher conversion is achieved at higher temperature due to the fact that at higher temperature kinetic constant (rate constant) is favorably affected resulting an increasing in phenol conversion, according to arrehenius equation:       −= rt e ak aexp (2) also, at hig h temperatures in aqueous solutions, the form in which oxygen participates in chemical reactions is complex. the elevated temperatures necessary can lead to the formation of oxygen radicals, o·, which in turn can react with water and oxygen to form peroxid e, h2o2, and ozone, o3, so that these four species o·, o2, o3, and h2o2 are all capable of participating in the phenol oxidation. fig. 10, effect of temperature on phenol oxidation. reaction cond.: type of catalyst= cat.4, feed solution ph = 7.3, s.e. = 80 %, whsv = 1 h-1, po2= 9 bar and cph = 4 g/l effect of oxygen partial pressure effect of oxygen partial pressures was illustrated in figure 11. compared to temperature, oxygen partial pressure has less influence on the phenol conversion. it can be seen from figure 11, increasing oxygen partial pressure from 6 bar to 12 bar resulted an increasing in phenol conversion from 87.3 % to 97.84 %, while increasing temperature from 120 to 160°c causes increasing in phenol conversion from 58.6 % to 92.4 %. in general, an increasing oxygen partial pressure causes an increasing in phenol conversion. in addition, elevated pressure is required in such process, increasing pressure increases the density of gas and it's solubility in the aqueous solution. also, an increasing in gas pressure may be provide a lateral push force for the reactants to cover as much surface area over catalyst as possible. 20 30 40 50 60 70 80 90 0 50 100 150 200 250 300 350 time, min x p h (% ) whsv = 3 whsv = 2 whsv = 1 h 20 30 40 50 60 70 80 90 100 0 50 100 150 200 250 300 350 time, min x p h ( % ) temp.=120 temp.=140 temp.=160 temp. =120° wadood t. mohammed et al ijcpe vol.8 no.4 (december 2007) 51 fig. 11, effect of oxygen partial pressure on phenol oxidation. reaction conditions: type of catalyst= cat.4, feed solution ph = 7.3, s.e. = 80 %, whsv = 1 h -1, t= 160°c and cph = 4 g/l effect of initial phenol concentration in the range of these experiments phenol conversion decreases by decreasing inlet phenol concentration illustrated in figure 12. this can be attributed to decrease phenol molecules coverage the active site over the catalyst surface. this allows adsorbing the intermediates over vacancy active sites and under the elevated conditions during oxidation process; these intermediates are converted to undesirable deposits. these deposits which cause catalyst deactivation can be indicated by observed changing catalyst color at the end of the oxidation process. fig. 12, effect of initial phenol concentration on phenol oxidation.reaction conditions: type of catalyst= cat.4, feed solution ph = 7.3, s.e. = 80 %, whsv = 1 h -1, t= 160oc and po2= 12 bar conclusions 1. the highest phenol conversion (97.84%) was achieved over the catalyst (cuo.nio/al2o3) under the conditions of [feed solution ph=7.3, s.e. =80%, whsv=1 h-1, temperature=160°c, oxygen partial pressure=12 bar, and initial phenol concentration=4 g/l]. 2. it was found that the catalyst composition of (cuo.nio/al2o3) is the active one among the other prepared catalysts. the following order is observed. cuo.nio/al2o3 > cuo.zno/al2o3 > cuo/al2o3 > cuo/sio2 3. the catalysts show fall in activity when feed solution ph is low regardless the support. after variable period, the alumina-support activity remains stable due to present two active species i.e. copper oxide and copper aluminates. in contrast, the silica-support activity decreases sharply until the phenol conversion is negligible due to present only copper oxide. 4. it was found that phenol conversion increases with increas ing gas flow rate until (s.e. =80%), after that decreases with increasing gas flow rate. 5. it was found that phenol conversion increases (56.8% 83.25%) as weight hour space velocity (whsv) decreases (3-1 h-1). 6. increasing reaction temperature causes enhancement in phenol conversion, and activity of catalyst. 7. increasing oxygen partial pressure (6-12 bar) causes increasing in phenol conversion (87.3% -97.84%). 8. as phenol concentration decrease, phenol conversion decrease at constant catalyst bed height. nomenclature a pre -exponential factor (case dependent units) ea activation energy j / mol k rate constant(case dependent units) r universal gas constant, 8.314 j / mol. k t time h t temperature k xph conversation of phenol references 1. miro, c., alejamdre, a., fortuny, a., bengoa, c. font, j. and fabregat, a., water research, 33, 1005-1013 (1999). 2. fortuny, a., miro, c., font, j. and fabregat, a., catalysis today, 48, 323-328 (1999). 3. singh, a., pant, k. k. and nigam, k. d. p., chemical engineering journal, 103, 51-57 (2004). 50 60 70 80 90 100 0 50 100 150 200 250 300 350 time, min x p h ( % ) p = 6 bar p = 9 bar p = 12 bar 2op =9 2op = 2op =6 40 50 60 70 80 90 100 0 50 100 150 200 250 300 350 time, min x p h ( % ) c = 1 g/l c = 2 g/l c = 4 g/l cph = catalytic wet air oxidation of phenol in a trickle bed reactor ijcpe vol.8 no.4 (december 2007) 52 4. fortuny, a., bengoa, c., font, j. and fabregat, a., a journal of hazardous materials, 64, 181-193 (1999). 5. wu, q., hu, x., yue, p.l., chemical engineering since, 58, 923-928 (2003). 6. eftaxias, a., font, j., fortuny, a., giralt, j., fabregat, a. and stuber, f., applied catalysisb: environmental , 33, 175-190 (2001). 7. wu, q., hu, x., yue, p.l., zhao, x.s., lu, g.q., applied catalysis b: environmental , 32, 151-156 (2001). 8. fenoglio, r., rolandi, p., massa, p. ganzalez, j. and haure, p., reactor, kinetic and catalysis letters, 31, 83-90 (2004). 9. massa, p.a., ayude, m.a., fenoglio, r.j., gonzalez, j.f. and haure, p.m., latin american applied research, 34, 133-140 (2004). 10. fortuny, a., font, j. and fabregat, a., applied catalysisb: environmental, 19, 165-173 (1998). 11. fortuny, a., ferrer, c., bengoa, c., font, j. and fabregat, a., catalysis today, 24, 79-83 (1995). ijcpe vol.9 no. 2 (june 2008) iraqi journal of chemical and petroleum engineering vol.9 no.2 (june 2008) 51-56 issn: 1997-4884 the effect of temperature and ph on the removal / recovery of zn ++ from solution by chemical coagulation dr.adil al –hemiri * and tahseen hameed al-taey * chemical engineering department, college of engineering, university of baghdad. abstract this work was conducted to study the treatment of industrial waste water, and more particularly those in the general company of electrical industries.this waste water, has zinc ion with maximum concentration in solution of 90 ppm. the reuse of such effluent can be made possible via appropriate treatments, such as chemical coagulation, na2s is used as coagulant. the parameters that influenced the waste water treatment are: temperature, ph, dose of coagulant and settling time. it was found that the best condition for zinc removal, within the range of operation used ,were a temperature of 20c a ph value of 13 , a coagulant dose of 15 g na2s /400ml solution and a settling time of 7 days. under these conditions the zinc concentration was reduced from 90mg/l to 0.003 mg/l. introduction heavy metals today have a great ecological significance due to their toxicity and accumulative behavior[1]. these elements contrary to most pollutants are not bio-degradable and undergo a global ecobiological cycle in which natural water are the main path way. the determination of the concentration level of heavy metals in this water as well as the elucidation of the chemical forms in which they appear (i.e. its specification) is a prime target in environmental research today because of the close relation between toxicity and specification. zinc is very rarely present in natural water, but not so rare in water when it is drawn at consumers' taps because of the use of galvanized iron piping and tanks. zinc should not exist in water consumed in quantities in excess of 15 ppm. some waters will readily take up zinc, especially in cooking process and zinc containers for food should not be used. another danger is the collection of drinking water from galvanized iron roofs for isolated supplies. hard chalk waters attack the zinc of galvanized piping, forming loose deposits of zinc carbonate, and the zinc in solution in such waters, as supplies to the consumers may be found to exist up 3.0 ppm[2]. zinc salts are also used in the inorganic pigments industry and high zinc levels have been reported in acid mine drainage water. the primary source of zinc in wastewaters from plating and metal product is after removal from pickling or plating baths. treatment process employed for wastewater zinc removal may involve either chemical precipitation, with disposal of the resultant sludge, or recovery process include ion exchange and evaporative recovery, but may also be precipitation process, where relatively pure zinc sludge is reclaimed. recovery of plating wastes frequently proves to be more economical on an overall basis than conventional precipitation and sludge disposal [3]. this investigation was conducted to study the effects of the variables on the zinc removal by chemical coagulation method using na2s as a coagulant[4]. the variables studied were : temperature, ph, coagulant dose settling time, these variable were correlated to zinc concentration remained in the treated wastewater to obtain the optimum condition for treatment process in order to obtain water with metal concentration not exceeding health standards as set by the environmental protection agency[5,6,7]. university of baghdad college of engineering iraqi journal of chemical and petroleum engineering the effect of temperature and ph on the removal / recovery of zn ++ from solution by chemical coagulation 52 ijcpe vol.9 no. 2 (june 2008) experimental work the experimental work entailed the treatment stage by chemical coagulation method using na2s as a coagulant and analysis of the wastewater before and after treatment. the study includes the effect of the ph, temperature, dose and settling time on the operation. the wastewater polluted with zinc, was obtained from the general company for electrical industries, where zinc is used as pigment to the cover of electrical parts. the experiments were carried out at : (i) temperatures of 20,30,40,50, and 60c0 (ii) ph of 3,5,7,10and 13 (iii) coagulant dose of 2.5,3.5,5,10,and 15 mg/400ml solution (iv) settling time of 0,1,2,3,4,5,6 and 7 days zinc treatment procedure 400ml solution was poured in a beaker then coagulant dose was added to the sample. naoh and hcl were used to control the ph degree of the sample which was measured by digital ph meter. this sample with known dose and ph was placed in water bath with temperature control. then the sample was stirred by using jar test or agitator for a period of (1/4 -1/2) hour. after this was completed, the sample was left quiescent for (1-7) day during which settling occur. finally the sample was analyzed. zinc analysis procedure titration method was used to measure zinc concentration in the sample after the treatment process (coagulation, flocculation, and settling) was finished. at first, the sample was filtered by filter paper (to remove any solid impurities) then, a 100 ml from the sample was taken and put in a titration beaker. the ph of this sample was then adjusted to a value of 10 by adding naoh or hcl (a ph of the sample equals to 10 is known as optimum for titration). a few drops of the indicator of erio chrome black t indicator were added to the sample to convert color to wine red. then the sample was titrated with 0.1 m of edta solution until the color of the sample is blue. the titration was stopped and the volume of edta used for the titration was recorded. this volume was used to calculate the concentration of zink in the samples. this analysis was repeated for all treated samples which come from treatment process at different conditions [8,9]. results and discussion there are many kinds of processes to remove zinc from industrial wastewater like ion exchange, biological method, liquid membrane, and absorption methods, besides coagulation process. the coagulation process was chosen to remove zinc from industrial wastewater because it is simple, economical, uses cheap substances and simple devices. there are many substances which can be used as a coagulant; na2s was chosen in this work because. it is cheap and widely found with low coagulation time (1/4-1/2) hour. the effect of temperature: the results obtained here are shown in figures(1-5) .the figures show the effect of increasing the temperature in removing zinc from a waste solution. it is obvious that increasing the temperature will decrease the amount of zinc removed. as it can be seen from figure (1), the amount of zinc removed at 20c is more than that removed at 30, 40, 50 and 60ºc. in general zinc removal, gradually decreases when the temperature was rising (other variables are constant). this behavior of zinc concentration in the treated solution sample and the temperature is a result of the solubility of the salt zns in water. where increasing the temperature will increase the reverse dissociation and zinc ions will form again as shown in the chemical equation zn +2+ na2s zn s + 2na+1 fig.1: the relation between the ph and the zinc concentration for different temperature values at constant dose (15g), constant settling time (7 day) 2 6 10 140 4 8 12 ph 0.05 0.15 0.25 0.35 0.45 0.55 0.00 0.10 0.20 0.30 0.40 0.50 0.60 z in c c o n c e n tr a ti o n ( m g /l ) t=60 t=50 t=40 t=30 t=20 dr.adil al –hemiri and tahseen hameed al-taey 53 ijcpe vol.9 no. 2 (june 2008) fig. 2: the relation between the ph and the zinc concentration for different temperature values at constant dose (10g), constant settling time (7 day) fig. (3) the relation between the ph and the zinc concentration for different temperature values at constant dose (5g), constant settling time (7 day) fig. 4: the relation between the ph and the zinc concentration for different temperature values at constant dose (3.5g), constant settling time (7 day) fig. 5: the relation between the ph and the zinc concentration for different temperature values at constant dose (2.5g), constant settling time (7 day) 2 6 10 140 4 8 12 ph 0.05 0.15 0.25 0.35 0.45 0.55 0.00 0.10 0.20 0.30 0.40 0.50 0.60 z in c co n ce n tr at io n ( m g /l) t=60 t=50 t=40 t=30 t=20 2 6 10 140 4 8 12 ph 0.10 0.30 0.50 0.00 0.20 0.40 0.60 z in c c o n c e n tr a ti o n ( m g /l ) t=60 t=50 t=40 t=30 t=20 2 6 10 140 4 8 12 ph 0.10 0.30 0.50 0.70 0.00 0.20 0.40 0.60 0.80 z in c c o n c e n tr a ti o n ( m g /l ) t=60 t=50 t=40 t=30 t=20 2 6 10 140 4 8 12 ph 0.30 0.50 0.70 0.20 0.40 0.60 0.80 zi nc c on ec tr at io n (m g/ l) t=60 t=50 t=40 t=30 t=20 the effect of temperature and ph on the removal / recovery of zn ++ from solution by chemical coagulation 54 ijcpe vol.9 no. 2 (june 2008) the effect of ph: the results obtained here shown in figures (6,). these figures show that when the ph increases, at constant temperature, dose, and settling time the zinc amount removed also increased. the amount of zinc removed when the ph is above 10 is more than the amount of zinc removed at other ph values, this difference in the quantity of zinc removed is due to the effect of the change in the ph on the zeta potential and solubility curve. when the ph increases, the zeta potential decreases, therefore, the coagulation will increase (i.e. zinc removal increases). also, at high values of ph the solubility of zns will decrease , so that the amount of zinc removed will increase then the concentration of zinc in the treated solution will decrease .for example at constant temperature (20c) , na2 s dose (15 g ), and settling time (7 days), zinc concentration left in solution after treatment is 0.0022, 0.0038, 0.005, 0.02 and 0.09 mg/l at ph values of 13,10,7,5 and 3 respectively ( see also table 1) . fig.6: the relation between the ph and the zinc concentration for different dose at constant temperature (t=20), constant settling time (7 day) the effect of dose: the results obtained here are shown in figures (7,8) the results show the effect of adding na2s dose on zinc removal. when the dose increases, the amount of zinc removed also increases, as it can be seen. the amount of zinc removed from the treated solution when the dose is (15 gm) was more than the amount of zinc removed when the na2s dose is 2.5 gm ( other parameters are constant). this behavior is due to requirement of the quantity of the na2s (chemical coagulant) to remove the zinc and forming the zns salt according to the chemical equation na2s+zn+2  2na+zns. at high value of chemical coagulant dose, zns formed will increase, so that the rate of zinc removal will, also, increase, i.e. concentration of zinc in the treated solution will decrease. for example at constant temperature (20٥c),constant ph(13) ,and for settling time (7days)for dose (15g) the zinc concentration in the solution is (0.0022 mg/l),while for dose (2.5g) the zinc concentration in the solution is (0.253mg/l). fig.7: the relation between the dose and the zinc concentration for different ph values at constant temperature (t=20 c), constant settling time (7 day) 2 6 10 140 4 8 12 ph 0.05 0.15 0.25 0.35 0.45 0.00 0.10 0.20 0.30 0.40 0.50 z in c c o n c e n tr a ti o n ( m g /l ) dose=15 gm dose=10 gm dose=5 gm dose=3.5 gm dose=2.5 gm 2 6 10 140 4 8 12 16 dose (gm/400 ml) 0.05 0.15 0.25 0.35 0.45 0.00 0.10 0.20 0.30 0.40 0.50 c o c e n tr a ti o n ( m g /l ) ph=13 ph=10 ph=7 ph=5 ph=3 dr.adil al –hemiri and tahseen hameed al-taey 55 ijcpe vol.9 no. 2 (june 2008) fig.8: the relation between the dose and the zinc concentration for different temperature values at constant (ph=13), constant settling time (7 day) the effect of settling time the result obtained here are shown in figures (9,10) which show the effect of settling time on the zinc removal from treated water. when the settling time increased, the quantity of zinc removed also increased as it can be seen. the quantity of zinc removed increased gradually with the time from one to seven days. this behavior is due to the effect of increasing the size of the particles because of coagulation as well as the settling of the finer particles at longer times. for example at constant temperature (20٥c) , constant ph (13) and dose (15 g na2s/400ml solution ) the value of zinc concentration was (0,172 mg/l)while it decreased to(0.144 mg/l) for the second day then to (0.1 mg/l ) for the third day, and in the seventh day zinc concentration is only (0.003 mg/l ) . fig.9: the relation between the settling time and the zinc concentration for different ph value at constant dose (10g), constant temperature (20 cº) fig.10: the relation between the settling time and the zinc concentration for different dose values at constant (ph=13), constant temperature (20cº) 2 6 10 140 4 8 12 16 dose (g/400ml) 0.05 0.15 0.25 0.35 0.45 0.55 0.00 0.10 0.20 0.30 0.40 0.50 0.60 z in c c o n c e n tr a ti o n ( m g /l ) t=60 t=50 t=40 t=30 t=20 1 3 5 7-1 2 4 6 8 settling time (day) 0.05 0.15 0.25 0.35 0.45 0.00 0.10 0.20 0.30 0.40 0.50 z in c c o n c e n tr a ti o n ( m g /l ) ph=12 ph=10 ph=7 ph=5 ph=3 1 3 5 70 2 4 6 8 settling time (day) 0.05 0.15 0.25 0.35 0.45 0.55 0.65 0.75 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 z in c co n ce n tr at io n ( m g /l) dose=2.5 gm dose=3.5 gm dose=5 gm dose=10 gm dose=15 gm the effect of temperature and ph on the removal / recovery of zn ++ from solution by chemical coagulation 56 ijcpe vol.9 no. 2 (june 2008) table 1 zinc ion concentration left in solution after treatment (temp. =200c; settling time = 7 days) conclusions the following conclusions could be drawn from the present investigation 1it was found that the best ph value for zinc removal was 13. 2it was found that the temperature effect on zinc removal by na2s show that zinc removal increased when the temperature decreased and the best temperature was 20٥c for removing the zinc from treated solution. 3it was found that the best dose for zinc removal from the wastewater was 15 gm na2s/400 ml polluted solution. 4it was found that the zinc removal increased when the settling time also increased. reference 1. degremont, (1979), "water treatment hand book", 5th ed., halstad press book, john wiley and sons, new york. 2. m. anis al-layla, shamim ahmed, and e. joe middlebrook, (1977), “water supply engineering design” mc-graw hill publication, u.s.a . 3. rafael pardo, enrique barrado, lourdes perez and marisol vega, (1990), "determination and specian of heavy metals in sediments of the pisurga river", j. of water research, vol.(24), no.(3) pp.(373-379). 4. watson, j.f., (1978), "waste water treatment technology", mc-graw hill publications, usa. 5. bradley r.s. and yuefeng xie, (2000) " using acid mine drainage sludge for heavy metals removal in wastewater", journal of water pollution control federation,61 (4) :481-490. 6. raymond, d.l., appiah a. and charls r.o., (1999), fifth edition, mcgraw-hill. 7. alley e.r., (2000), "water quality control handbook", mcgraw-hill. 8. vogel,(1976) "inorganic analysis including" third edition,g.b. 9. al – taey ,t. h. ,(2004) “the effect of temperature and ph on removal/ recovery of zn++ from the solution by chemical coagulation ,m.sc . thesis, 2.5 15 15 15 15 15 na2s dose (g/400 mls.) 13 13 10 7 5 3 ph 0.253 0.0022 0.0038 0.005 0.02 0.09 concentration mg/l) ijcpe vol.9 no.1 (march 2008) 35 iraqi journal of chemical and petroleum engineering vol.9 no.1 (march 2008) 35-43 issn: 1997-4884 characteristic performance of deionized columns matheel d. al-sabti*, nahidh w. kasser**, mudhafar y. hussein** * university of technology, baghdad, iraq ** university of technology, baghdad, iraq *** university of misan abstract the reclamation of makeup water is studied in terms of breakthrough time (i.e., the leakage of the cations). makeup water was subjected to lab-scale ion exchangers of two types: strong acid cation and weak base anion exchanger. the experimental investigation was directed to study the ion exchanger performance in terms of four different parameters (i.e., copper concentration, total dissolved solids (tds), feed rate and bed depth). box-wilson composite rotatable design was adopted in designing the experiments. breakthrough times of the effluent stream are measured in terms of copper concentration of 2 to 25 ppm, tds concentration of 250 to 1250 ppm, feed rate of 0.38 to 5.34 l/h and bed depth of 5 to 70 cm. simulation the effect of the studied variables through their pre-designed ranges in terms of breakthrough time was done by 2nd order polynomial equation. in general, the performance and characteristic of adopting two bed deionizers (cation and anion beds) was efficiently recommended to remove the ionic contaminants and not less than 95 % of wastewater is recycled. keywords: characteristic performance, columns, reclamation, deionized. introduction the fact that most ion exchange process is equilibrium reaction necessitating a continuous contacting of the exchanger with fresh electrolyte in order to drive the reaction to completion. the column technique a most widely used method for conducting ion exchange reaction. column operation is like several batch reactors in series. the column operation is essentially an elaborate multiple batches wise technique in which the upper most portion of the column is constantly contacting fresh electrolyte whereas the lower portions contact the electrolyte not adsorbed by the upper exchanger. this procedure permits the exchanger bed to become fully exhausted at the top first and then gradually downward[1]. the ion exchange process is an alternative technique for application in the treatment of industrial wastewater containing heavy metals and indeed it has proven to be very promising in the removal and recovery of valuable species[2]. water treatment, however, is the most important application of ion exchange; the main areas of interest are water softening, de-mineralization or deionization (the product of high purity water)[3]. deionization removes all of ions from the water, leaving only non-ionic materials in solution[4]. these resins have university of baghdad college of engineering iraqi journal of chemical and petroleum engineering characteristic performance of deionized columns ijcpe vol.9 no.1 (march 2008) 36 been classified based on the charge in the exchangeable counter ion (cation exchanger or anion exchanger) and the ionic strength of the bound ion (strong exchanger or weak exchanger)[5]. ion exchange is a chemical treatment process used to remove unwanted ionic species from wastewater. the ions are not destroyed but rather are removed from the waste stream and concentrated on the resin, where they can be more easily handled[6,7). ion exchange technology was applied in many studies to treat for example nickel ion from plating wastewater which contains heavy metal, bringing environmental problems such as chromium, zinc, copper, and lead[8]. it is used to further improve the removal efficiency of the color, fe concentration, conductivity, alkalinity and total dissolved solids (tds)[9]. the ion exchange process is an alternative technique for application in the treatment of industrial wastewater containing heavy metals and indeed it has proven to be very promising in the removal and recovery of valuable species[10]. in industrial practice where a solution flows through the ion exchange resin, equilibrium is not necessarily reached and the results are influenced by kinetic considerations. the ratedetermining step of ion exchange is the diffusion of the mobile ions toward, from and in the resin phase, rather that the chemical reaction between fixed ions of the resin and mobile counter ions[11]. the present experimental investigation studies the most affecting parameters on ion exchanger performance. studying the behavior of ionic exchangers was carried out at different concentration of cu+2 ions, different tds content, different flow rates, and different ion exchanger heights (cation and anion). precipitation of ions of toxic heavy metals generated from regeneration was studied by adding 20 % cao aqueous solution. these toxic heavy metals are precipitated as hydroxide. the operating conditions using aqueous solutions containing nacl, cuso4 are shown below. selecting of salts of two kinds of ions cu+2 and na+ are recommended to study their influence on each other. this will give an idea about the behavior of the ion exchangers towards monovalent and divalent ions. also the study is directed to consider the reclamation system through characterizing the performance of two bed deionizers (cation and anion beds) towards removing ionic contaminants. an experimental design is necessary to find useful relationships between controllable variables and observed response. experimental work experimental design the simplest experiment is a comparison of two things that differ in just one attribute. this sort of experiment obviously has a practical value, but it offers little insight. to gain such insight, more variables must or have to be considered whether there is a quantitative relationship between variable and response and what the form is, linear, quadratic, etc. having established such a relation, the effect of other variables would examine in the same manner. variables acting together may have a greater or smaller effect than individual variables acting alone. a response surface can be most efficient fitted if proper attention is given to the choice of experimental design[12]. the systematic method, which satisfies the above function with minimum number of experiments, is called “experimental design”. the application of the experimental design for planning the experiments required to examine the system, will extract the information from pre–existing data by using a statistical method to interpret the results in regular form with the minimum number of observations[14]. this analysis will give description for the system by a correction in order to predict the effect regarding the change of variables on the objective function. also, the polynomial representation will facilitate the analysis of the system by many techniques, such as optimization of process conditions, required for the maximum value of the objective function[12,13]. an experimental design for fitting a second–order model must have at least three levels for each factor so that the model parameters can be estimated (i.e. variables are usually called factor and the particular value of the variable is called the level). the proper technique for planning a system of more than three variables is “central composite rotatable design”. the total number of treatment combinations is equal to  122  kk , where k is the number of variables, plus additional further treatments to take the lack of fit and experimental error into account. this design consists of k 2 fractional (i.e. coded to the usual  1 notation) augmented by 2k axial points, i.e. (  , 0, …,0), (0,  , 0, …,0), (0, 0,  , …, 0), ……, (0, 0, …,  ) and center points (0, 0, 0, …, 0). a preliminary step is to set up the relationships between the coded levels and the corresponding real variables. these relationships are as follows (box and george, 1978):            k xx xx x center centeractual coded .min (1) finally, the number of experiment (n) needed is estimated according to the following equation: 122  kn k (2) matheel d. al-sabti, nahidh w. kasser and mudhafar y. hussein ijcpe vol.9 no.1 (march 2008) 37 the experimental trials using makeup water were designed to produce demineralized water through the following experimental ranges: (1) copper concentration between 5 to 25 ppm. (2) total dissolved salts (tds) between 250 to 1250 ppm. (3) flow rate of wastewater between 0.38 to 5.34 l/h. (4) bed depth for cation resin between 5 to 70 cm and for anion resin between 7.5 to 105 cm. according to eq (1) the coded levels are related to the real variables as follows:        6............. 16.25 37.5b ,5............. 1.23 2.85f 4............ 250 750 ,3.............. 5 15 xx c x c x 43 t 2 c 1         where cc is the concentration of copper in ppm, ct is the total dissolve solid in ppm, f is the feed rate in l/h, and b is bed depth of cation resin in cm. the working ranges of coded and corresponding real variables are listed in table (1). accordingly, there are 28 experiments in a sequence shown in table (2) where the coded values +2, -2, 0 represent the maximum, minimum and average values respectively. table 1 coded and corresponding real variables coded level cu conc. (ppm) tds conc. (ppm) feed rate (l/h) bed depth (cm) -2 -1 0 1 2 5 10 15 20 25 250 500 750 1000 1250 0.38 1.62 2.85 4.08 5.34 5.00 21.25 37.50 53.75 70.00 table 2 sequence of experiments exp. no. coded variable real variable x1 x2 x3 x4 cu +2 conc. (ppm) tds conc. (ppm) feed rate (liter/hr) bed depth (cm) 1 -1 -1 -1 -1 10 500 1.62 21.25 2 1 -1 -1 -1 20 500 1.62 21.25 3 -1 1 -1 -1 10 1000 1.62 21.25 4 1 1 -1 -1 20 1000 1.62 21.25 5 -1 -1 1 -1 10 500 4.08 21.25 6 1 -1 1 -1 20 500 4.08 21.25 7 -1 1 1 -1 10 1000 4.08 21.25 8 1 1 1 -1 20 1000 4.08 21.25 9 -1 -1 -1 1 10 500 1.62 53.75 10 1 -1 -1 1 20 500 1.62 53.75 11 -1 1 -1 1 10 1000 1.62 53.75 12 1 1 -1 1 20 1000 1.62 53.75 13 -1 -1 1 1 10 500 4.08 53.75 14 1 -1 1 1 20 500 4.08 53.75 15 -1 1 1 1 10 1000 4.08 53.75 16 1 1 1 1 20 1000 4.08 53.75 17 -2 0 0 0 5 750 2.85 37.5 18 2 0 0 0 25 750 2.85 37.5 19 0 -2 0 0 15 250 2.85 37.5 20 0 2 0 0 15 1250 2.85 37.5 21 0 0 -2 0 15 750 0.38 37.5 22 0 0 2 0 15 750 5.34 37.5 23 0 0 0 -2 15 750 2.85 5.0 24 0 0 0 2 15 750 2.85 70.0 25 0 0 0 0 15 750 2.85 37.5 26 0 0 0 0 15 750 2.85 37.5 27 0 0 0 0 15 750 2.85 37.5 28 0 0 0 0 15 750 2.85 37.5 also, precipitation of heavy metals ions especially for copper ions from concentrated solution after regeneration was studied. the experiments were designed in the following ranges: (1) copper concentration between 293 to 1500 ppm. (2) ph value between 8.6 to 11.4. the working ranges of coded and corresponding real variables are listed in table (3). accordingly, there are (12) experiments as listed in table (4) where the coded values +1.414, -1.414, 0 represent the maximum, minimum and average values respectively. table 3 working range of coded and corresponding real variables coded level copper concentration (ppm) ph -1.414 -1 0 1 1.414 293 500 1000 1500 1707 08.586 09.000 10.000 11.000 11.414 table 4 sequence of experiments exp. no. coded variable real variable cu (ppm) x1 x2 copper conc. (ppm) ph 1 -1 -1 500 9 0.66 2 -1 1 500 11 0.50 3 1 -1 1500 9 0.10 4 1 1 1500 11 0.50 5 0 0 1000 10 0.30 6 0 0 1000 10 0.35 7 0 0 1000 10 0.25 8 0 0 1000 10 0.27 9 1.414 0 1707 10 0.40 10 -1.414 0 293 10 0.75 11 0 1.414 1000 11.414 0.38 12 0 -1.414 1000 8.586 0.2 operating conditions cu +2 concentration ranged between 5 to 25 ppm coded as x1 tds ranged between 250 and 1250 ppm coded as x2 flow rate ranged between 0.38 to 5.34 l/h coded as x3 bed height of cation ranged between 5 to 70 cm coded as x4 bed height of anion ranged between 7.5 to 105 cm the breakthrough point was decided to be when the effluent stream reads 40µs/cm conductivity. the average conductivity of the whole produced water after each run was found equal to 10-15 µs/cm (correspond to tds content of 5 to 7.5 ppm). testing these experiments was characterized on periodical measurements of electric characteristic performance of deionized columns ijcpe vol.9 no.1 (march 2008) 38 conductivity of the effluent stream. each sample was measured three times and average value was considered. the tds content was obtained by dividing the readings of the electric conductivity by two. the experiments are conducted in following sequence: (1) removing the toxic metals by ion exchangers; (2) concentrating them by regeneration solution; (3) precipitating the small volumes of concentrated solution as hydroxides by lime. monitoring the tds concentration in deionized water was carried out by measuring the electric conductivity of effluent whereas others ions concentrations such as ca++, mg++, cl-, etc. are measured by other instrumental techniques. chemicals the following chemicals are used:  4 % hcl solution for regeneration of cation exchanger.  4% naoh solution for regeneration of anion exchanger.  strongly acidic cation exchanger, type ir – 120 of mesh size 14-50 (rohm & haas), amberlite.  weakly basic anion exchanger type lewatit of mesh sizes 20-50 (bayer), lewatit. measuring devices the following instrumental apparatus are used:  flame & flameless atomic absorption spectrophotometer, type shimadzu aa – 680 g. japan, was used to determine concentration of cu++, na+, ca++, mg++, …etc.  ph meter, type titro-processor 686 metrohm swiss made.  conductivity meter, type 83 copenhagen denmark made, ranged between 0 to 3000 µs/cm.  turbidity meter, type hach company model 43900 was used to test concentration of so4=, and cl-. apparatus the experimental rig consists mainly of two columns for the cation and anion exchangers that were incorporated with dosing pumps. a schematic diagram of the apparatus was shown in fig (1). the following specification of the columns, valves and dosing pumps are listed below: glass columns of 90-cm long and 2.54 cm diameter. dosing pumps: cfg prominent electronic, type b02– 035 sweden flow rate 0 – 34.92 liter/hr fig. 1 flow sheet for wastewater treatment experimental procedure preparation step  conditioning of the ion exchangers columns c1 and c2 are packed with strongly acidic cations exchanger and weakly basic anion exchangers respectively. the two columns were soaked with deionized water with bed volume of two–third of the column volume (i.e., exchanger packed no bubbles exist between its particles).  back washing upward washing of the ionic exchangers (columns c1 and c2) with 10-bed volume/h using industrial water was lasted for 10 to 15 minutes to ensure entertainment of dirt and fine particles from the resin bed. water for back washing was delivered using pump 1. regeneration step  regeneration of the cation exchanger regeneration of the cation exchanger was carried out by 4 % hcl solution. the acid solution was pumped from tank t2 through pump 2 into column c1 downward with flow rate of 4-bed volume/h. regeneration step was lasted for 75 minutes.  rinsing step downward 4-bed volume/h industrial water was pumped into column c1 via pump 1. this step was lasted for 15 minutes, then rinsing with 8-bed volume/h for 30 minutes. matheel d. al-sabti, nahidh w. kasser and mudhafar y. hussein ijcpe vol.9 no.1 (march 2008) 39  regeneration of the anion exchanger downward 4-bed volume/h of 4 % naoh solution was pumped from tank t3 via pump 3 into column c2. the regeneration was lasted for 45 minutes.  rinsing step downward industrial water was pumped into column c1 and column c2 via pump 1 with 4-bed volume/h. the rinsing step was lasted for 15 minutes, then rinsing with 8-bed volume/h till a residual conductivity of 40 µs/cm was detected. flowing stage/nacl-cuso4 solution nacl/cuso4 solution is pumped via pump 1 into column c1 (cation exchanger) and into column c2 (anion exchanger) with different feed rates. the flowing of solution was kept during the experiment until breakthrough point was detected at conductivity reading of 40 µs/cm. results and discussion table (5) lists the experimental breakthrough time at the pre-designed operating conditions of the studied variables as listed in table (3). when the response or dependant variable influenced by independent variables, and when it is necessary to optimize this response, it is reasonably assumed that the independent variables are continuous and controllable by the experimenter with negligible error. in most rsm problems, the form of the relationship between the response and the independent variables is unknown. usually, a second order polynomial in some region of the independent variables is employed. if the fitted surface is an adequate approximation then analysis of the fitted surface will be approximately to analysis of the actual system. customarily, method of least squares is used to estimate the parameters in the approximating polynomial. using the experimental breakthrough times, the coefficients were estimated using nonlinear regression analysis technique via program software named statistica. the number of iterations was terminated when the proportion of variance accounted for was equal to 0.977, and the correlation coefficient (r) 0.93149. correlating the four variables with breakthrough time, the following model was determined: 43 42324131 21 2 4 2 3 2 2 2 1 4321 259574.1 333949.1900425.1030796.108517.1 015796.1666129.0862981.4658826.0677027.0 209096.4962403.7172569.4744315.0642605.7 xx xxxxxxxx xxxxxx xxxxy     optimum values at maximum breakthrough time were determined applying hooks and jeeves optimization technique and found equal to: maximum breakthrough time: x1 = 5 ppm, x2 = 250 ppm, x3 = 0.38 l/h, x4 = 70 cm; to emphases the effect of each variable on breakthrough time clearly and individually, each variable was studied separately (i.e. other variables are kept constant at optimum values). as shown in figs (2) to (5), the effect of studied variables (i.e., copper concentration, total dissolved solids, and flow rate and bed depth) on the breakthrough time was investigated. these fig.s indicates that the breakthrough time of the ion exchanger is decreased with increase in copper concentration, total dissolved solids concentration and flow rate and increased with bed height. the reasons for these characteristics are attributed as follows: various criteria influencing the general performance of ion exchange resin, however, relative selectivity of the resin for various ionic species has been considered into account in this situation since a strong cation resin operating in the h + form will preferentially exchange ions with different selectivity. it seems that earlier breakthrough time starts to occur with higher concentration of copper ions because cu +2 ions start to replace na + ions in the cation exchanger also so4 -2 ions starts to replace cl ions in the anion exchanger due to their higher selectivities that resulted in leak off the resin earlier. fig. 2 effect of copper concentration on the breakthrough time 0 10 20 30 40 50 60 70 80 90 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 copper concentration b r e k th r o u g h t im e ( h ) characteristic performance of deionized columns ijcpe vol.9 no.1 (march 2008) 40 0 10 20 30 40 50 60 70 80 90 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 bed depth b re a k th ro u g h t im e ( h ) 0 10 20 30 40 50 60 70 80 90 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 feed rate b re a k th ro u g h t im e ( h ) fig. 3 effect of tds concentration on the breakthrough time fig. 4 effect of feedrate on the breakthrough time fig.5 effect of bed depth on the breakthrough time with higher concentration of total dissolved solids, the concentration of ions in solution increases that raises the mass transfer rate through the film until it exceeds the diffusion rate through the resin beads. this condition means that the leakage curve is spread out over deeper reaction zone. if this condition is happened it leads to shorter exhaustion time and lower operating capacity. if the flow rate is slow enough, equilibrium is established as the solution reaches a new layer of the resin that means the wave front is only slightly diffuse as a result of each successive layer of resin being almost completely exhausted before leakage occurs. as flow rate increases, equilibrium is no longer reached and the exhaustion curve is spread out over deeper reaction zone which has a smaller operating capacity and earlier breakthrough point. the operating capacity is defined as the proportion of total capacity used during the exchange process. it can amount to a large or small proportion of the total capacity and depends on a number of process variables including depth of resin bed. it was simply observed that the longer the column, the greater is the operating capacity of the resin and consequently later breakthrough time which is simply attributed to the deeper is the reaction zone. to study the interaction effects between the studied variables, figs (6) to (11) were drawn. the effect of total dissolved solids concentration on the breakthrough time at different copper concentration was studied as represented in fig (6). it shows that increasing the tds concentration will decrease the breakthrough time as outlined above in studying the effect of tds concentration on breakthrough time. this observation had come in accordance with neretnieks justification who had previously pointed out that diffusion rate is controlled by the concentration gradient that takes longer contact time to reach adsorption equilibrium and exhaustion point for the case of low values of initial solute concentration(14). however, at higher concentration of tds the resin leaks off earlier with lower copper concentration, which indicates reverse action of copper concentration on the breakthrough time (i.e., at coded value -2 corresponding to real value 5 ppm). this can be attributed to pronounce selectivity of cu++ ions with respect to na+ ions at higher concentration of cu+2 that resulted in lately breakthrough time in comparison to lower concentration. fig. (7) demonstrates the interaction effect between flow rate and copper concentration. the breakthrough time decreases with increasing flow rate as previously monitored in fig (4). also, fig (2) shows earlier breakthrough time with increasing copper concentration. however, same observation has been noticed at the extreme limit of flow rate (i.e., high flow rate) as found in fig (6) that increasing copper concentration has shown lately breakthrough time. once again, this can be attributed as declared above to the lower concentration of copper ions that resulted in faster uptake of cu+2 ions and earlier breakthrough time. 0 10 20 30 40 50 60 70 80 90 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 tds concentration b re a k th ro u g h t im e ( h ) matheel d. al-sabti, nahidh w. kasser and mudhafar y. hussein ijcpe vol.9 no.1 (march 2008) 41 table 5 experimental breakthrough time exp. no. coded variable real variable exp. breakthro. time (h) pred. breakthro. time (h) x1 x2 x3 x4 copper conc. ppm tds ppm flow rate l./hr bed depth cm 1 -1 -1 -1 -1 10 500 1.62 21.25 10.75 15.18 2 1 -1 -1 -1 20 500 1.62 21.25 10.50 15.18 3 -1 1 -1 -1 10 1000 1.62 21.25 5.47 11.42 4 1 1 -1 -1 20 1000 1.62 21.25 5.30 7.73 5 -1 -1 1 -1 10 500 4.08 21.25 2.67 3.55 6 1 -1 1 -1 20 500 4.08 21.25 2.88 0.14 7 -1 1 1 -1 10 1000 4.08 21.25 1.20 -0.35 8 1 1 1 -1 20 1000 4.08 21.25 1.15 0.297 9 -1 -1 -1 1 10 500 1.62 53.75 28.9 34.47 10 1 -1 -1 1 20 500 1.62 53.75 28.8 30.84 11 -1 1 -1 1 10 1000 1.62 53.75 14.4 17.63 12 1 1 -1 1 20 1000 1.62 53.75 14.22 18.06 13 -1 -1 1 1 10 500 4.08 53.75 12.00 10.06 14 1 -1 1 1 20 500 4.08 53.75 12.00 10.77 15 -1 1 1 1 10 1000 4.08 53.75 5.20 0.81 16 1 1 1 1 20 1000 4.08 53.75 5.10 5.59 17 -2 0 0 0 5 750 2.85 37.5 7.69 6.42 18 2 0 0 0 25 750 2.85 37.5 7.38 3.45 19 0 -2 0 0 15 250 2.85 37.5 21.87 18.62 20 0 2 0 0 15 1250 2.85 37.5 3.90 1.93 21 0 0 -2 0 15 750 0.38 37.5 56.50 43.02 22 0 0 2 0 15 750 5.34 37.5 2.90 11.17 23 0 0 0 -2 15 750 2.85 5 0.57 -3.44 24 0 0 0 2 15 750 2.85 70 14.60 13.39 25 0 0 0 0 15 750 2.85 37.5 7.72 7.64 26 0 0 0 0 15 750 2.85 37.5 7.75 7.64 27 0 0 0 0 15 750 2.85 37.5 7.60 7.64 28 0 0 0 0 15 750 2.85 37.5 7.50 7.64 fig. (8) demonstrates the interaction effect between bed depth and copper concentration. it seems that increasing the bed depth whatever copper concentration will increase the breakthrough time. this was attributed as previously outlined that the longer the column, the deeper is the reaction zone, and the greater is the operating capacity of the resin and consequently lately breakthrough time. but, herein it seems that the bed depth has pronounced effect on breakthrough time relative to copper concentration even though the two variables have opposite effect on breakthrough time, but still bed height tends to higher breakthrough time as if there is no influence of copper concentration on the breakthrough time. fig. (9) shows the interaction effect between flow rate and tds concentration. in this fig. it seems that no interaction had been noticed, besides, the effect of both variables had come in according with each other in the direction of decreasing breakthrough time with increasing flow rate and tds concentration. fig. (10) shows the interaction effect between bed depth and tds concentration. herein, the concentration of tds almost counterbalance the effect of bed height on breakthrough time especially at highest concentration of tds since no significant variations in breakthrough time was observed with increasing bed height. fig. (11) show the interaction effect between flow rate and bed depth. both variables tend to affect the breakthrough time in opposite direction but it seems that the flow rate has the most significant effect on breakthrough time in comparison to bed height. fig. 6 effect of copper concentration and tds concentration on the breakthrough time 0 10 20 30 40 50 60 70 80 90 -2 -1 0 1 2 3 total dissolved solid (tds) b r e a k th r o u g h t im e ( h ) for x1=-2 for x1=-1 forx1=0 for x1=1 for x1=2 copper concentration characteristic performance of deionized columns ijcpe vol.9 no.1 (march 2008) 42 fig. 7 effect of copper concentration and flow rate on the breakthrough time fig. 8 effect of copper concentration and bed depth on the breakthrough time fig. 9 effect of tds concentration and flow rate on the breakthrough time fig. 10 effect of tds concentration and bed depth on the breakthrough time fig. 11 effect of bed depth and flow rate on the breakthrough time conclusions the following conclusions can be pointed out: 1. it was shown that the studied four variables affect the breakthrough time in the following sequence: x3 > x4 > x2 > x1 2. pronounced effect of bed depth on the breakthrough time was found. 3. the effect of flow rate on breakthrough time indicates that higher flow rate leads to lesser breakthrough time which means higher amounts of total dissolved solids adsorbed at lower flow rate for a given time besides it contributes to lower residence time inside the column. 4. it was ascertained that various criteria influencing the general performance of ion exchange resin as the strong cation resin operating in the h + form will preferentially exchange ions with different selectivity that resulted in earlier breakthrough time with 0 10 20 30 40 50 60 70 80 90 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 flow rate b re a k th ro u g h t im e ( h ) for x1=-2 for x1=-1 forx1=0 for x1=1 for x1=2 copper concentration 0 10 20 30 40 50 60 70 80 90 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 bed depth b r e a k th ro u g h t im e ( h ) for x1=-2 for x1=-1 forx1=0 for x1=1 for x1=2 copper concentration 0 10 20 30 40 50 60 70 80 90 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 bed depth b r e a k th ro u g h t im e ( h ) for x2=-2 for x2=-1 for x2=0 for x2=1 for 2=2 total disolved solids 0 10 20 30 40 50 60 70 80 90 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 flow rate b r e a k th ro u g h t im e ( h ) for x4=-2 for x4=-1 for x4=0 for x4=1 for x4=2 bed depth matheel d. al-sabti, nahidh w. kasser and mudhafar y. hussein ijcpe vol.9 no.1 (march 2008) 43 increase in concentration of copper ions due to its higher selectivity in comparison to na + ions. 5. higher concentration of tds leads to higher concentration of ions in solution that resulted to higher mass transfer rate through the film until it exceeds the diffusion rate through the resin beads and consequently the system is exhibited particle controlled kinetics that means deeper reaction zone. 6. with slow flow rate, it seems that the wave front is only slightly diffuse as a result of each successive layer of resin being almost completely exhausted before leakage occurs and resulted to an earlier breakthrough point till no tendency to decrease at higher flow rates since the process exhibits particle controlled kinetics where no influences might contributed from further increase in flow rate. references 1. kunin r., “ion exchange resin”, rohm & haas company, 2nd ed., new york, john wily & sons inc., 1963. 2. sofia a. cavaco, sandra fernandes, margarida m. quina and licínio m. ferreira; journal of hazardous matewrials, volume 144, issue 3, 18 june 2007, 634638 3. abb instrumentation, “ion exchange simply explained”, technical support department, may, 1999, (internet). 4. remco engineering, "power purge deionization systems high efficiency di", website: http://www.remco.com/ix.htm.,2000, (internet). 5. aldrich, "ion exchange resins: classification and properties", aldrich technical bulletin al-142, jan, 2002, (internet). 6. danny d. r., “fundamentals of environmental engineering”, 1999. 7. paul l. b., “pollution prevention: fundamental and practice”, mcgraw hill companies, 2000. 8. tae-hyoung eom, chang-hwan lee, jun-ho kim and choul-ho lee; desalination, volume 180, issues 1-3, 15 august 2005, 163-172. 9. raghu s. and ahmed basha c.; journal of hazardous matewrials, article in press, accepted 30, march, 2007 (internet). 10. sofia a. cavaco, sandra fernandes, margarida m. quina and licínio m. ferreira; journal of hazardous matewrials, volume 144, issue 3, 18 june 2007, 634-638. 11. ullmans, ”encyclopedia of industrial chemistry”, vch, 1989. 12. box and george e. p., “statistics experimenters”, new york, 1978. 13. cox d. r., “planning of experiments”, new york, 1958. 14. neretieks i.; chem. sci., vol. 31, p. 465, 1976. http://www.remco.com/ix.htm.,2000 ijcpe vol.9 no.1 (march 2008) 9 iraqi journal of chemical and petroleum engineering vol.9 no.1 (march 2008) 9-14 issn: 1997-4884 effect of promoters on the catalytic activity of the iosmerization catalyst abdul-halim a.k. mohammed*, marwan gaib and mohammed nasief abbass * chemical engineering department college of engineering university of baghdad – iraq abstract the crystalline zeolite, namely faujasite type y with sio2/al2o3 mole ratio of 5 was used as raw material for preparation of isomerization catalysts. a 0.5 wt % pt/hy-zeolite catalyst was prepared by impregnation of the decationized hy-zeolite with chloroplatinic acid. the dectionized hy-zeolite was treated with hcl, hno3 and hi promoters using different normalities and with different concentrations of sn, ni and ti promoters by impregnation method to obtain acidic and metallic promoters' catalysts, respectively. a 0.5 wt% of pt was added to above catalysts using impregnation method. isomerization of n-hexane was carried out at different prepared catalysts. the isomerization temperature varied from 250–325° c over weight hourly space velocity (whsv) 1.6 h -1 . the pressure and hydrogen to feed mole ratio were kept constant at 1bar and 2 mol/mol, respectively. the comparison between the above prepared catalysts shows that the total isomer yield during the process with sn-pt /hyzeolite catalyst was higher than the other catalysts and, reached to 63.95% vol. a 0.5 wt% of w and zr was added to sn-pt/hy-zeolite catalyst by impregnation method to obtain w and zr co-metal promoters catalysts. isomerization of n-hexane was investigated using w and zr co-metal promoters catalyst at the same operating conditions and the yield of isomers reached to 81.14% vol.and 79.07%vol.,respectively. keywords: isomerization, catalyst, catalytic activity, promoters. introduction isomerization is a catalytic process involves rearrangement of the molecular structure of a hydrocarbon without gain or loss of any of its components [1], in order to increase octane number of hydrocarbon fraction. the main commercial applications during world war ii and in a limited way thereafter were the isomerization of butane to isobutane, pentane to isopentane [2,3], and naphtha or normal hexane fractions into a higher octane number gasoline. in these processes aluminum chloride is used with anhydrous hydrochloric acid as a liquid slurry or complex, on a granular alumina or bauxite support and dissolved in molten antimony trichloride. in all processes the feed must be dried so that moisture is not carried into the acid zone, but corrosion may be severe. university of baghdad college of engineering iraqi journal of chemical and petroleum engineering biotreatment technique to treat oil wells drilling wastes ijcpe vol.9 no.1 (march 2008) 10 a refinery after 1956 almost completely utilizing all available cracked gases by polymerization and alkylation, and low octane gasoline is being upgraded by catalytic reforming. thus, other means of upgrading octane number, notably isomerization, will be explored in an effort to upgrade pentane and hexane. the isomerization process after 1957 was used the system of dual function catalyst (silica alumina) and hydrogenation catalysts such as nickel-silica-alumina or platinum-silica-alumina or similar catalyst which contains both metallic sites and acidic sites [1]. recently, modern isomerization process uses zeolite bi-functional catalyst [4]. gray and cobb [5] studied mordenite catalysts with various cations ,prepared by a reflux ion exchange technique using chloride or nitrate salts and were tested for activity in the hydroismerization and hydrocracking of n-pentane. the extent of sodium ion exchange possible followed the order: nh 4+ > ba 2+ > sr 2+ > ca 2+ >mg 2+ >la 3+ maximum catalyst activities for h-m, ca-m and la-m occurred at calcination temperature of 510, 525 and 400° c, respectivly. zhorov, kartashev and panchekov [6] studied the isomerizing activity of decationized mordenite and faujasite in the isomerization activity of cyclohexane and n-hexane in isothermal reactor at 200-300° c and space velocity of 1.5 h -1 . the catalyst activated at 450° c for 5 h in air flow and dealuminized using edta and hcl. they found that type y zeolite was more active and selective in the isomerization of n-paraffins than mordenite but the latter was more selective for isomerization of naphthenes. prins, massoth and somorjai [7] studied the isomerization reaction of n-pentane and n-hexane over lay, nay, sry, ni-lay, ni-nay and ni-sry zeolites and observed that the obtained data deiviated from the ideal second-order kinetic model. lee and woo [8] studied the isomerization of butane, pentane and hexane over hy, tiy, h-zsm-5 and ti zsm-5 zeolites in the temperature range of 277-352° c and at atmospheric pressure. they found that the isomeriztion reaction of butane, pentane and hexane is first order reaction. the aim of this investigation is the study of the effect of different catalyst promotors loaded on pt/hy zeolite catalyst on the n-hexane isomerization. experimental work feedstock n-hexane supplied from reidel de haen was used as raw material for isomerization activity test. the properties of n-hexane are shown in table 1. table 1 n-hexane properties specification value molecular weight 86.17 purity (%) 99.8 density (g/cm 3 ) 0.659 boiling point (°c) 68.8 catalyst preparation preparation of hy-zeolite 25 g of nay-zeolite was slurried in 0.5 liter of 4n ammonium chloride [9] aqueous solution and left overnight for the ion exchange completion. the exchanged zeolite was filtered off, washed with deionized water and dried at 110° c overnight [10]. the dried exchanged zeolite was calcined initially at 150° c then the temperature increased to 525° c with a rate of 75°c/h [11]. during calcination, nh3 and water are liberated and decationized hy-zeolite powder is formed. the prepared hy-zeolite was reduced with hydrogen at 380° c [12] for three and half hours at hydrogen linear velocity 3.38  10 -4 m/s. the prepared catalyst powder was then fabricated as a spherical shape with 20% sodium silicate as a binder and calcined at 400° c for 5 hours. preparation of decationized 0.5%wt pt/hyzeolite a 25 g of prepared hy-zeolite powder was used for the preparation of 0.5% pt/hy-zeolite by impregnation method using impregnation apparatus shown in the fig 1. fig. 1 impregnation apparatus 1.3688 g of hcl was mixed with a solution of 0.3125 g of chloroplatnic acid (h2ptcl6) and 82 ml of water. the akram h. al-hiti et al ijcpe vol.9 no.1 (march 2008) 11 resultant solution is added drop by drop to 25 g of prepared hy-zeolite with continuous agitation. then, the sample mixed by using a magnetic stirrer for 2 hours to have a homogeneous distribution of chloro platinic acid. then, the slurry was dried at 110°c overnight and calcined at 400° c for 5 hours. the calcined catalyst was reduced with hydrogen at 380° c for three and half hours at a hydrogen linear velocity 3.38  10 -4 m/s. the prepared catalyst powder pt/hy-zeolite was then formulated as a spherical shape with 20% sodium silicate as a binder and calcined at 400° c for 5 hours. preparation of decationized pt/hy-zeolite with different acidic promoters hcl, hno3 and hi used in different normalities to obtain hy-zeolite catalyst with different acidity. a 25 g of decationized hy-zeolite is added to solutions of 2, 4, 6 and 8 n of hcl, hno3 and hi, respectively. then, the samples were filtered off through buchuner funnel and washed with deionized water to be free of anions, and dried at 110°c overnight. a 1.3688 g of hcl was found necessary to add in the solution of 0.3125 g of chloroplatinic acid and 82 ml of water to get a macroscopic homogeneous distribution of pt inside the hy-zeolite pores. then the resulted solution was added to each sample of the promoted catalysts as a drop by drop with continuous agitation and then mixed by using a magnetic stirrer to have a homogeneous distribution of chloroplatinic acid. evaporation of samples was carried out at 140° c for 1 hour. the impregnated powders were then dried at 110° c overnight, and calcined at 400° c for 5 hours. the calcined catalysts were reduced with hydrogen at 380° c for three and half hours at hydrogen linear velocity 3.38  10 -4 m/s. the prepared catalyst powders were then formulated as a spherical shape with 20% sodium silicate as a binder and calcined at 400° c for 5 hours. preparation of decationized pt/hy-zeolite with different metal promoters the decationized hy-zeolite was used to prepare catalysts containing different concentrations of sn, ti and ni. a 25 g of decationized hy-zeolite was charged into impregnation apparatus evacuation is operated to remove the air from the pores of the carries hy-zeolite. the impregnation solutions are prepared by dissolving different quantities of sncl4, ticl2 and nicl4 in different quantities of decationized water. the impregnation process was accompanied with shaking for 4 hours at mixed temperature of 20° c. the impregnated products are then dried at 110° c overnight and dried catalysts are calcined at 400° c for 5 hours. a 1.3688 g of hcl adds to the solution of 0.3125 g of chloroplatinic acid h2ptcl6 and 82 ml of water to get macroscopic homogeneous distribution of pt inside the hy-zeolite pores. then, the total solution was added to each sample of above prepared catalysts as a drop by drop with continuous agitation and then mixed by using a magnetic stirrer to have a homogeneous distribution of impre-gnation solution. the impregnated powders were then dried at 110° c overnight, and calcined at 400° c for 5 hours. the calcined catalysts were reduced with hydrogen at 380°c for three and half hours at a linear velocity of hydrogen 3.38  10 -4 m/s. the prepared catalyst powder was then formulated as a spherical shape with 20% sodium silicate as a binder and calcined at 400° c for 5 hours. preparation of decationized pt/hy-zeolite with different co-metal promoters the decationized hy-zeolite was used to prepare two catalysts with tungsten and zirconium promoters. the first one containing 0.5 wt% pt, 2 wt% sn and 0.5 wt% w, while the second catalyst contains 0.5 wt% pt , 2 wt% sn and 0.5 wt% zr. the first co-promoter solution was prepared by dissolving 2 g of ammonium meta tungsten in 15 ml of the decationized water, while the second co-promoter solution was prepared by dissolving 0.833 g of zirconium tetra chloride in 20 ml of decationized water. the catalyst (w-sn-pt/hy-zeolite) was prepared by adding the first co-promoter solution to above prepared sn-pt/hy-zeolite as a drop by drop with continuous agitation and then mixed by using magnetic stirrer, while the catalyst (zr-sn-pt/hy-zeolite) was prepared by adding the second co-promoter solution to above prepared sn-pt/hy-zeolite using the same previous procedure. the impregnated material then dried at 110°c, calcined at 400° c for 5 hours, and reduced with 3.3810 -4 m/s of hydrogen at 380° c for three and half hours. the prepared catalysts were then formulated as a spherical shape with 20% sodium silicate as a binder and calcined at 400° c for 5 hours. isomerization unit the isomerization experiments were carried out in a laboratory unit. the process diagram of this unit is shown in fig. 2 .the unit consists of heater storage, reactor, chiller and condenser. the reactor of this unit is a stainless steel tube with 80 mm inside diameter, 2 mm wall thickness and 750 mm length. it was packed with 25g of catalyst between two layers of inert material. the reactor is heated and controlled automatically by temperature controller. isomerization operating conditions isomerization of n-hexane was carried out using different prepared catalysts. the temperature range varied from 250 to 325° c. the pressure, weight hourly space biotreatment technique to treat oil wells drilling wastes ijcpe vol.9 no.1 (march 2008) 12 velocity and hydrogen/hydrocarbon mole ratio were kept constant at 1 bar, 1.6 h -1 and 2 mol/mol, respectively. fig. 2 isomerization unit results and discussion comparison between hy-zeolite and 0.5%wt pt/hyzeolite catalysts figure 3 shows the effect of temperatures on the isomerization activity (total isomer yield) using hyzeolite catalyst, and pt/hy-zeolite catalyst. the comparison between two curves shows that the total isomer yield of pt/hy-zeolite was higher than that of hy-zeolite. the mechanism of n-paraffin isomerization as mentioned by gates et.al. [13] has three steps, nparaffin’s is dehydrogenated to n-olefins which occur on the metal sites, n-olefins isomerize to iso-olefins which occur on the acid sites and of iso-olefins hydrogenated to isoparaffin which occur on the metal sites again. therefore, the increasing in the total isomer yield may be due to the addition of platinum which activates the hydrogenation/ dehydrogenation activity [1]. furthermore, both curves show that as temperature increases the rate of isomerization reactions increases too. effect of acidic promoters on the catalytic activity figures 4 to 6 show that the effect of temperature on the isomerization activity using hcl, hno3 and hi promotors with different concentrations on hy-zeolite and pt-hy-zeolite. these figures show that the activity increases after the addition of hi, hcl and hno3 compared with hy-zeolite and pt/hy-zeolite without promotors; and with increasing the concentration of the acid promoters. this may be due to the active acid sites increasing after the addition of the acid promoters and that may be lead to enhance the isomerization of n-olefins to iso-olefins which occurs on the acid sites. these figures also show that the activity increase with increasing the reaction temperature exception one curve in figure 4 in which the catalytic activity increases until 300° c and then decrease. this may be due to the considerable enhancing effect of acidic promoters which emerged when the hy-zeolite had been adsorbed them at higher temperature when the oh groups (causing the catalytic activity of hy-zeolite) will be supplied by the dissociation of the acidic promoters added. the ability of acidic promoters to enhance the activity of the hy-zeolite at high temperatures can be attributed to the newly formed oh groups [14]. it’s clearly shown from fig.s 4-6 that the higher activity (total isomer yield) was obtained using hi. this may be due to the reverse reaction of hi in its aqueous solution. hcl and hno3 are completely dissociated in its aqueous solution, while hi is partially dissociated in its aqueous solution [15]. when the temperature increases in calcination cl , i and no 3 an ions are liberated from hcl, hi and hno3, respectively with some h + ion causing a decrease in isomerization activity. effect of metal promoters on the catalytic activity figures 7 to 9 show the effect of temperature on the isomerization activity at different concentrations of metal promoters supported on pt/hy-zeolite. these figures show that the total isomer yield increases after the addition of sn, ni and ti compared with hy-zeolite, pt/hy-zeolite and acidic promoters supported on hyzeolite, and the activity increases with increasing the concentration of metal promoter. this result may be due to the metal hydrogenation/ dehydrogenation activity increasing after addition of metal promoters. also these figures show that the increasing in temperature increases the catalytic activity then the activity begin to decrease exception some curves in the above figures in which the catalytic activity increases with increasing temperature . it is generally accepted that the catalytic activity of hy-zeolite is caused by the oh groups playing the role of bronsted acid sites. the oh concentration decreases considerably when the hy-zeolite had been treated at the high temperatures which lead to a decrease in the catalytic activity. these results are in agreement with otsuka, et.al.work [15]. higher activity (63.95% yield) was obtained with sn promoter. this may be due to ni and ti mild hydrogenation/dehydrogenation activity, while sn has strong hydrogenation activity as mentioned also by rechardson [16] . akram h. al-hiti et al ijcpe vol.9 no.1 (march 2008) 13 effect of co-metal promoters on the catalytic activity figure 10 shows the effect of temperature on the isomerization activity using co-metal promoters (w and zr) supported on hy-zeolite. this figure and the previous figures show that the activity increases after the addition of zr and w compared with hy-zeolite, pt/hy-zeolite, acidic promoters supported zeolite and metal promoters supported on hy-zeolite. this result may be due to the increasing of the hydrogenation/ dehydrogenation metal function of the catalyst. figure 10 also shows that the activity increases with increasing the reaction temperature up to 275° c then begins to decrease, and the w promoted catalyst gives higher isomer yield than zr promoted catalyst and the maximum isomers yield with w promotor reaches to 81.14% vol. at 275° c. temperature, °c t o ta l is o m e r y ie ld 8 12 16 20 24 28 32 240 260 280 300 320 340 hy-zeolite pt / hy-zeolite fig. (3) effect of isomerization 0.5%wt temperature on the catalytic activity using hy-zeolite and pt / hyzeolite temperature, °c t o ta l is o m e r y ie ld 24 25 26 27 28 29 30 31 32 33 240 260 280 300 320 340 hcl (2n) hcl (4n) hcl (6n) hcl (8n) fig. (4) effect of isomerization temperature on the catalytic activity using hcl-pt / hy-zeolite temperature, °c t o ta l is o m e r y ie ld 23 25 27 29 31 33 240 260 280 300 320 340 hno3 (2n) hno3 (4n) hno3 (6n) hno3 (8n) fig. (5) effect of isomerization temperature on the catalytic activity using hno3-pt / hy-zeolite temperature, °c t o ta l is o m e r y ie ld 28 29 30 31 32 33 34 35 240 260 280 300 320 340 hi (2n) hi (4n) hi (6n) hi (8n) fig. (6) effect of isomerization temperature on the catalytic activity using hi-pt / hy-zeolite temperature, °c t o ta l is o m e r y ie ld 25 30 35 40 45 50 55 60 65 70 75 240 260 280 300 320 340 360 sn (0. 5 wt%) sn (1. 0 wt%) sn (1. 5 wt%) sn (2. 0 wt%) fig. (7) effect of isomerization temperature on the catalytic activity using sn-pt / hy-zeolite biotreatment technique to treat oil wells drilling wastes ijcpe vol.9 no.1 (march 2008) 14 temperature, °c t o ta l is o m e r y ie ld 20 25 30 35 40 45 50 55 60 65 70 75 80 85 240 260 280 300 320 340 ti (0. 5 wt%) ti (1. 0 wt%) ti (1. 5 wt%) ti (2. 0 wt%) fig. (8) effect of isomerization temperature on the catalytic activity using ti-pt / hy-zeolite temperature, °c t o ta l is o m e r y ie ld 25 30 35 40 45 50 55 60 65 240 260 280 300 320 340 ni (0. 5 wt%) ni (1. 0 wt%) ni (1. 5 wt%) ni (2. 0 wt%) fig. (9) effect of isomerization temperature on the catalytic activity using ni-pt / hy-zeolite temperature, °c t o ta l is o m e r y ie ld 77. 0 77. 5 78. 0 78. 5 79. 0 79. 5 80. 0 80. 5 81. 0 81. 5 240 260 280 300 320 340 360 sn pt zr sn pt w fig. (10) effect of isomerization temperature on the catalytic activity using co promoters catalysts conclusions 1. hi promoter enhances the catalytic activity higher than hcl and hno3 promoters. 2. the metal promoters varied in increasing of catalytic activity and addition of sn promoter gives higher activity (63.95%yield) than ni and ti. 3. the temperature 275° c gives the higher isomerization activity (the higher isomer yield) for metal sites promoters. 4. the addition of promoters have an important influence on the catalytic activity (total isomer yield) of isomerization of n-hexane reaction, and this influence is varied from one type of promoters to another. 5. the enhancement of isomerization activity at 275° c take the order: 6. co-metal promoters > metallic promoters > acidic promoters (maximum yield81.14% vol.) (maximum yield 63.95% vol.) (yield 29.98% vol.) references 1. meyers, a. robert, “handbook of petroleum refining process.” mcgraw hill, new york (1996). 2. perry, s.f. trans. a. i. ch. e., 42, 639 (1946). 3. galstan, l.s., oil and gas j., jan. 5, 1946, p.56. 4. breck, d.w., “zeolite molecular sieves”, weil, intersience, newyork (1974). 5. gray, j.a., and cobb, j.t., j.catal., 3b, 125 (1975). 6. zhorov, yu.m., kartashev, yu.n. and panchekov, g.m. petro.chem., 23,61 (1983). 7. prins, r, massoth, f.e. and somorijai, g.a., cata.rev. sci. eng. 105,228 (2001). 8. lee, d.k., and woo, s.i, cat. 26, 323 (2002). 9. anderson, j. r., “structure of metallic catalysts”, academic press inc., london (1975). 10. sivasanker, s., ramaswamy, a. v. and ratnasamy, p. “factors controlling the retention of chlorine in platinum reforming catalysts”, preparation of catalyst ii (delmon, b., gange, p., jacobs, p. and poncelet,g., eds.). p185, elsevier, amsterdam (1979). 11. gray, j. a., and cobb, j. t., j. catal., 36, 125 (1975). 12. blanchard, g., charcosset, h., chenebaux, m. t. and primet, m., “preparation of alumina or silica supported platinum-ruthenium bimetallic catalysts”, preparation of catalysts ii (delmon, b., grange, p., jacobs, p. and poncelet, g.), p. 197, elsevier, amsterdam (1979). 13. gates, b.c, katzer j,r and shuit g.c , 1979 “chemistry of catalytic process” , mc graw hill, newyork. 14. chemistry of zeolite, effect of acids treating on the activity, web site: www.akzonobel.com ,2004. 15. otsuka, ,k., iwakura, t. and morikawa, a. “activity-promotions by sncl4 and hcl on decationated-y and na-y zeolite”, catalysis by zeolite, (imelik, b., naccache, c., ben taarit, y., vedrine, j.c. ,co-udurier,g. and praliaud, h., eds.), p 57, elsevier, amsterdam(1980). 16. richardson, j. t., “principles of catalyst development”, plenum press, new york (1989). http://www.akzonobel.com/ ijcpe vol.10 no. 3 (september 2009) iraqi journal of chemical and petroleum engineering vol.10 no.3 (september 2009) 9-17 issn: 1997-4884 recovery of catalyst from tar formed in phenol production unit wadood t. mohammed and sami m. zaboon chemical engineering department college of engineering university of baghdad – iraq abstract this work was conducted to study the recovery of catalyst and desirable components from tar formed in phenol production unit and more particularly relates to such a method whereby better recovery of copper salts, phenol, benzoic acid and benzoate salts from tar by aqueous acid solution was accomplished. the effect of solvent type, solvent concentration (5, 10, 15, 20, 25 and 30 wt%), agitation speed (100, 200, 300 and 400 rpm), agitation time (5, 10, 15, 20 and 25 min), temperature (90, 100, 110, 120, 130 and 140 oc) , phase ratio (1/1, 2/1, 3/1, 4/1 and 5/1) and number of extraction (1, 2, 3, 4, and 5) were examined in order to increase the catalyst and desirable components extraction. four types of solvent were used; hydrochloric acid, acetic acid, propanoic acid and butanoic acid with different concentration. the results of this work exhibit that the highest removal of copper 80.2 wt%, phenol 89.1 wt%, benzoic acid 90.7 wt% and benzoate salts 87.3 wt% were obtained under the conditions of acetic acid-water of 15%, agitation speed = 300 rpm, agitation time = 20 min, temperature = 120c, phase ratio (a/o) = 4 / 1, and number of extraction cycle = 4. introduction phenol is one of the most important starting materials for various chemical products, such as phenol resin, bisphenol, aniline and some agricultural chemicals. there currently are four process routes (1-5) being used commercially to produce synthetic phenol. three are based on benzene (1-3) and one on toluene. (4) the major process, which accounts for about 90 % of world capacity, is the cumene hydroperoxide route.(5) the other benzene routes, accounting for less than 4 %, include a chlorination and sulfonation process. the toluene based process, which involves the intermediate production of benzoic acid accounts for 6-8 %. beside the desired phenol the reaction yields, as a byproduct, highly viscous product which, during the reaction, remains in solution in the liquid carboxylic acid or derivative. this tarry byproduct must be removed from the reaction mixture and the carboxylic acid or derivative and the catalyst is dissolved by the extraction liquids. the composition of the reaction mixture that is withdrawn from the phenol preparation reactor depends on, among other things, the catalyst system used, the concentration of the catalyst and the starting materials and the process conditions. (6 21) phenol tar is a heavy, viscous byproduct produced in the industrial synthesis of phenol and acetone. phenol tar is a complex mixture, which comprises phenol, acetophenon, dimethyl benzeyl alcohol, alpha-methyl styrene dimmers, p-cumyl phenol, small amount of salts and many other chemicals in smaller amounts. it is difficult to dispose of phenol tar in an environmentally acceptable manner. specifically, burning phenol tar is not good disposal solution because it contains many ingredients, which do not burn readily, such as phenol. therefore, a need exists to find more environmentally acceptable methods of disposing of phenol tar (22-24). the present study reduces pollution resulting from the disposal of phenol tar by extracting valuable chemicals from the tar that can be recycled, thus reducing the university of baghdad college of engineering iraqi journal of chemical and petroleum engineering recovery of catalyst from tar formed in phenol production unit 10 vol.10 no.3 (september 2009) amount of phenol tar that must be disposed of. thus this study is intended to recover the copper catalyst and desired components from the tar formed in phenol production unit through the studying different effects of extraction process such as solvent kind, solvent concentration, agitation speed, agitation time, temperature, phase ratio and number of extraction cycle. experimental work experimental apparatus the experimental apparatus shown in figure 1 was used to extract the copper catalyst and desirable components from tar. the apparatus consisted mainly of the stainless steel autoclave, which had the dimensions 13 cm in diameter and 18 cm high. the autoclave consisted of two parts: lower part, a vessel that contained the materials to be treated. the other part (upper part) is the cover, with a hole, so that the four blades mixer is passed through. to ensure the prevention of the escape of vapors, the hole was checked to be tightly closed. there were also two side holes. the first one was used to measure the pressure. through the other hole, a thermocouple, type j (constantan-iron), was passed. this was connected to a digital thermometer. the autoclave was surround by a heating source, i.e., the heating tape and it was connected to a thermostat. a variac was used to establish the required temperature. the autoclave was further surrounded by an insulating material, i.e., glass wool to further ensure the heat conservation. other laboratory glassware were also used to carryout the experiments such as: beakers, pipetts, conical flasks, test tubs and graduated cylinders. fig. 1, schematic diagram of the experimental equipment experimental procedure at the beginning of the experiment, the tar was melted at 90o c to ensure its homogeneity with the catalyst. then it was crushed by hand. according to the working conditions a certain volumetric sample of the tar and the solvent was taken and was heated to the required temperature simultaneously with continuous mixing. at the end of the experiment according to experimental design, the autoclave was left to cool and the sample from the aqueous solution was taken to be tested and to determine the percentage of copper, phenol, benzoic acid and benzoate salts in it. atomic absorption spectrophotometer and gas chromatography were used to measure the concentration of copper and desirable components in the aqueous phase throughout the experiments. arrangement of experiments solvent selectivity in this set of experiments, solvent selectivity was investigated. the aqueous phase (solvent) used is diluted acid of hydrochloric acid, acetic acid, propanoic acid and butanoic acid with concentration of 5, 10, 15 and 20 % (v/v), keeping other variables constant (3/1 phase ratio, 110o c temperature, 300 rpm agitation speed and 15 min mixing time). a sample of the aqueous phase was taken to evaluate the concentration of copper, phenol, benzoic acid and benzoate salts. effect of solvent concentration in this set of experiments, the effect of the solvent concentration was investigated, the ranges of the concentration of the extractant is 5, 10, 15, 20, 25 and 30 % (v/v), keeping other variables constant (3/1 phase ratio, 110o c temperature, 300 rpm agitation speed and 15 min mixing time). effect of agitation speed in this set of experiments, the effect of agitation speed was investigated. a sample of the solution was taken at the end of each run of different speed versus 100, 200, 300, and 400 rpm. keeping other variables constant (3/1 phase ratio, 110o c temperature, and 15 min mixing time). effect of agitation time in this set of experiments, the effect of agitation time was investigated. a sample of the solution was taken at the end of each period 5, 10, 15, 20 and 25 min. keeping wadood t. mohammed and sami m. zaboon 11 vol.10 no.3 (september 2009) other variables constant (3/1 phase ratio, 110o c temperature). effect of temperature in this set of experiments, the effect of temperature was investigated. a sample of the solution was taken at the end of each run of different temperature versus 90, 100, 110, 120, 130 and 140o c. keeping phase ratio (3/1). effect of phase ratio in this set of experiments, the effect of phase ratio (a/o) was investigated. the phase ratio used in this set varied versus 1/1, 2/1, 3/1, 4/1 and 5/1. so according to the phase ratio above, a known volume of aqueous and organic phase was mixed. effect of number of extraction cycle in this set of experiments, the effect of number of extraction cycles was investigated. a sample of the solution was taken at the end of each run of different cycles i.e. 1, 2, 3, 4 and 5. keeping other variables constant at the best values from the previous sections. results and discussion solvent selectivity the results obtained, here, showing that using acetic acid as an extractant gave the highest recovery of copper catalyst and desirable components from tar. keeping other variables constant (3/1 phase ratio, 110o c temperature, 300 rpm agitation speed and 15 minutes mixing time). the aliphatic acids which are useful include all acids which are soluble to an extent of at least about 0.5 weight percent and preferably to at least about 9.5 weight percent in water. the preferred aliphatic acids are saturated and contain 1 to 4 carbon atoms. more preferred are the 2-4 carbon atom alkanoic acids. more preferred is acetic acid as shown in the results. aqueous formic acid is a good copper extractant, but on recycling to the phenol reactor it would be oxidized in the presence of copper salt. therefore, if it is employed, the valuable components are preferably separated from the aqueous phase without recycle. acetic, propionic and butyric acids are not oxidized appreciably on recycle and thus are preferably used, because they can be readily recovered from the aqueous of the phenol reaction system for reuse in the tar extraction process. figures 2 to 6 indicate that acetic acid gave the highest recovery of copper and desirable components, also gave the highest extraction coefficient. effect of solvent concentration from the results of the previous section, water-acetic acid soultion gave the highest recovery of copper and desirable components. the proportion of the two solvents in the solvent mixture is not critical, though of course enough of each must be used to produce two phases in the solvent mixture. also, there must be enough of each to dissolve to suspend substantially all of those components which are intended to be separated. it is, of course, desirable to operate with as small a volume of solvent as will do the job. the results clearly demonstrate that increasing the acid concentration up to 15 % causes the recovery of copper and desirable components increase, beyond that it remains almost constant. the concentration of the aliphatic acid in water can range from about 5 to about 50 weight percent. the upper limit of acid concentration is not determined by the ability of the acid to extract copper and the desired constituents from the tar only, but the ability to achieve phase separation of tar from the aqueous acid. the preferred alkanoic acid concentration ranges from about 10 to 20 percent in water, preferably 15 percent. figures 7 to 9, exhibit the effect of solvent concentration on recovery of copper and desirable components. effect of agitation speed as noticed from the previous sections that water15 % acetic acid was used to carry out the experiments in this section. figures 10 to 12 show that the agitation speed of 300 rpm gave the highest values of copper recovery and desirable components also. the surface area of the dispersed phase will depend on the amount of the agitation speed. however, it should not be thought that the greater the agitation speed the greater the rate of components extraction. too much agitation speed can result in formation of a solute or semi-stable emulations. furthermore, decreasing the drop size of dispersed phase can result in making the drop resemble rigid spheres. in this condition, there is no internal movement within the spheres, no new surfaces are produced and the extraction within the sphere cannot get to the surface to reach with solute. consequently, the extracting rate is slow (25). effect of agitation time the results are plotted in figures 13 to 15 indicating that using an agitation time of 20 min gave the highest extracting coefficient and percentage of copper and desirable components removal. the solvent extraction is an equilibrium process, it was found that the equilibrium is completed at 20 min of contact time and the increasing recovery of catalyst from tar formed in phenol production unit 12 vol.10 no.3 (september 2009) in the agitation time has no influence on the loading of aqueous phase. the mixing or contact time for the extracting of copper and desirable components from the tar-containing liquid reaction mixture must be sufficient to obtaine equilibrium between the polymeric tar and the aqueous aliphatic acid phase. this depends on the mixing vessel configuration, rate of stirring and efficiency of stirrers. settling time for separating the aqueous liquid and tar phases must be sufficient to allow the upper aqueous phase to become substantially free of any significant quantity of suspended tar. settling time can range from about 10 to 20 min to achieve a clear phase. effect of temperature the results plotted in figures 16 to 18 indicate that increasing the temperature lead to an increase in the extracting coefficient and percentage of copper and desirable components recovery. the temperature at which the extracting is affected can range from 90 to about 140o c. below 90o c the tar is solid and is difficult to extract except by resort to long extraction period. above about 140o c, the vapor pressure of the aqueous acid becomes troublesome. the preferred extraction temperature is about 140o c. in this way, substantially all the phenol, benzoic acid and benzoate salts were dissolved in the aqueous phase. this phase was then separated from the tar phase and returned to the reactor as part of the water fed thereto. effect of phase ratio the results obtained, showing that increasing the phase ratio (a/o) cause a significant increase in the extracting coefficient and the phase ratio 4/1 gave the highest value for the system as indicated in figure 19. this might be attributed to the increase in the quantity of transferred component which is related to quantity of extracting that will furnish the necessary molecules to reach the equilibrium state. the behavior is valid to an extent beyond it the extracting coefficient will decrease, because the quantity or volume of the aqueous phase increases, the amount of metal transferred will undergo somewhat smaller increase leading to a decrease in the concentration of metal. hence, causing a decrease in the extracting coefficient. figures 20 and 21 further support the above conclusion where these figures represent the percentage recovery of copper and desirable components, this percentage increases up to a limit then it remains nearly constant. the proportions of the aqueous alkanoic acid to tar can range from about 1/1 to 5/1 volume. as the ratio of aqueous acid to liquid reaction mixture reduced below 1/1, the separation of tar and aqueous acid phase becomes progressively more difficult. at a ratio above 5/1, the increased quantities of recycled dilute aqueous alkanoic cause evaporative overloading of the phenol reactor. effect of number of extraction the results obtained, showing that increasing the number of extraction cause a significant increase in the extracting coefficient up to a limit then it becomes nearly constant as show in figure 22. multiple extractions results increased removal of copper from the tar, but as the number of extractions increase the total amount of copper removed per extraction tends to decrease. at equilibrium the second and all succeeding extraction tend to have progressively lower copper concentrations in the liquid phase. figures 23 and 24 further support the above conclusion where these figures represent the percentage recovery of copper, phenol, benzoic acid and benzoate salts. acid concentration, wt% 4 6 8 10 12 14 16 18 20 22 c o p p e r re c o v e ry , w t% 0 5 10 15 20 25 30 hcl acetic acid propanoic acid butanic acid fig. 2, copper recovery versus acid concentration at 3/1 phase ratio, 110 o c temperature, 300 rpm agitation speed and 15 minutes mixing time acid concentration, wt% 0 5 10 15 20 25 e x tr a c ti o n c o e ff ic in e t (c o p p e r) * 1 0 3 0 20 40 60 80 100 120 hcl acetic acid propanoic acid butanic acid fig. 3, extracting coefficient versus acid concentration at 3/1 phase ratio, 110o c temperature, 300 rpm agitation speed and 15 minutes mixing time wadood t. mohammed and sami m. zaboon 13 vol.10 no.3 (september 2009) acid concentration, wt% 4 6 8 10 12 14 16 18 20 22 p h e n o l re c o v e ry , w t% 10 20 30 40 50 60 hcl acetic acid propanioc acid butanic acid fig. 4, phenol recovery versus acid concentration at 3/1 phase ratio, 110o c temperature, 300 rpm agitation speed and 15 minutes mixing time acid concentration, wt% 4 6 8 10 12 14 16 18 20 22 b e n z o ic a c id r e c o v e ry , w t% 10 20 30 40 50 60 70 hcl acetic acid propanic acid butanic acid fig. 5, benzoic acid recovery versus acid concentration at 3/1 phase ratio, 110o c temperature, 300 rpm agitation speed and 15 minutes mixing time acid concentration, wt% 4 6 8 10 12 14 16 18 20 22 b e n z o a te s a lt s r e c o v e ry , w t% 0 10 20 30 40 50 60 hcl acetic acid propanoic acid butanoic acid fig. 6, benzoate salts recovery versus acid concentration at 3/1 phase ratio, 110o c temperature, 300 rpm agitation speed and 15 minutes mixing time acid concentration, wt% 0 5 10 15 20 25 30 35 c o p p e r re c o v e ry , w t% 0 5 10 15 20 25 30 fig. 7, copper recovery versus acid concentration at 3/1 phase ratio, 110o c temperature, 300 rpm agitation speed and 15 minutes mixing time acid concentration, wt% 0 5 10 15 20 25 30 35 e x tr a c ti o n c o e ff ic in e t (c o p p e r) * 1 0 3 0 20 40 60 80 100 120 140 fig. 8, extraction coefficient versus acid concentration at 3/1 phase ratio, 110o c temperature, 300 rpm agitation speed and 15 minutes mixing time acid concentration, wt% 0 5 10 15 20 25 30 35 d e s ir a b le c o m p o n e n ts r e c o v e ry , w t% 15 20 25 30 35 40 45 phenol benzoic acid benzoate salts fig. 9, desirable components recovery versus acid concentration at 3/1 phase ratio, 110o c temperature, 300 rpm agitation speed and 15 minutes mixing time recovery of catalyst from tar formed in phenol production unit 14 vol.10 no.3 (september 2009) agitation speed, rpm 50 100 150 200 250 300 350 400 450 c o p p e r re c o v e ry , w t% 19 20 21 22 23 24 25 26 fig. 10, copper recovery versus agitation speed at water15% acetic acid solution, 3/1 phase ratio, 110o c temperature and 15 minutes mixing time agitation speed, rpm 50 100 150 200 250 300 350 400 450 e x tr a c ti o n c o e ff ic in e t (c o p p e r) * 1 0 3 80 85 90 95 100 105 110 115 fig. 11, extraction coefficient versus agitation speed at water-15% acetic acid solution, 3/1 phase ratio, 110o c temperature and 15 minutes mixing time agitation speed, rpm 50 100 150 200 250 300 350 400 450 d e s ir a b le c o m p o n e n ts r e c o v e ry , w t% 10 15 20 25 30 35 40 phenol benzoic acid benzoate salts fig. 12, desirable components recovery versus agitation speed at water-15% acetic acid solution, 3/1 phase ratio, 110o c temperature and 15 minutes mixing time mixing time, min 0 5 10 15 20 25 30 e x tr a c ti o n c o e ff ic in e t (c o p p e r) * 1 0 3 60 80 100 120 140 160 180 fig. 13, extraction coefficient versus mixing time at water-15% acetic acid solution, 3/1 phase ratio, 110o c temperature and 300 rpm agitation speed mixing time, min 0 5 10 15 20 25 30 c o p p e r re c o v e ry , w t% 16 18 20 22 24 26 28 30 32 34 fig. 14, copper recovery versus mixing time at water15% acetic acid solution, 3/1 phase ratio, 110o c temperature and 300 rpm agitation speed mixing time, min 0 5 10 15 20 25 30 d e s ir a b le c o m p o n e n ts r e c o v e ry , w t% 10 15 20 25 30 35 40 45 phenol benzoic acid benzoate salts fig. 15, desirable components recovery versus mixing time at water-15% acetic acid solution, 3/1 phase ratio, 110o c temperature and 300 rpm agitation speed wadood t. mohammed and sami m. zaboon 15 vol.10 no.3 (september 2009) temperature, o c 80 90 100 110 120 130 140 150 e x tr a c ti o n c o e ff ic in e t (c o p p e r) * 1 0 3 100 120 140 160 180 200 220 240 260 280 fig. 16, extraction coefficient versus temperature at water-15% acetic acid solution, 3/1 phase ratio and 300 rpm agitation speed temperature, o c 80 90 100 110 120 130 140 150 c o p p e r re c o v e ry , w t% 24 26 28 30 32 34 36 38 40 42 44 46 fig. 17, copper recovery versus temperature at water15% acetic acid solution, 3/1 phase ratio and 300 rpm agitation speed temperature, o c 80 90 100 110 120 130 140 150 d e s ir a b le c o m p o n e n ts r e c o v e ry , w t% 20 30 40 50 60 70 phenol benzoic acid benzoate salts fig. 18, desirable components recovery versus temperature at water-15% acetic acid solution, 3/1 phase ratio and 300 rpm agitation speed phase ratio (a/o) 0 1 2 3 4 5 6 e x tr a c ti o n c o e ff ic in e t (c o p p e r) * 1 0 3 120 140 160 180 200 220 240 260 280 300 320 fig. 19, extraction coefficient versus phase ratio at water15 % acetic acid solution, 140o c temperature, 300 rpm agitation speed and 20 min mixing time phase ratio (a/o) 0 1 2 3 4 5 6 c o p p e r re c o v e ry , w t% 10 20 30 40 50 60 fig. 20, copper recovery versus phase ratio at water-15 % acetic acid solution, 140o c temperature, 300 rpm agitation speed and 20 min mixing time phase ratio (a/o) 0 1 2 3 4 5 6 d e s ir a b le c o m p o n e n ts r e c o v e ry , w t% 20 30 40 50 60 70 80 phenol benzoic aicd benzoate salts fig. 21, desirable components recovery versus phase ratio at water-15 % acetic acid solution, 140o c temperature, 300 rpm agitation speed and 20 min mixing time recovery of catalyst from tar formed in phenol production unit 16 vol.10 no.3 (september 2009) no. of extraction cycle 0 1 2 3 4 5 6 e x tr a c ti o n c o e ff ic in e t (c o p p e r) * 1 0 3 200 400 600 800 1000 1200 fig. 22, extraction coefficient versus no. of extraction cycle at water-15 % acetic acid solution, 140o c temperature, 300 rpm agitation speed and 20 min mixing time no. of extraction cycle 0 1 2 3 4 5 6 c o p p e r re c o v e ry , w t% 50 55 60 65 70 75 80 85 fig. 23, copper recovery versus no. of extraction cycle at water-15 % acetic acid solution, 140o c temperature, 300 rpm agitation speed and 20 min mixing time no. of extraction cycle 0 1 2 3 4 5 6 r e c o v e ry , w t% 65 70 75 80 85 90 95 phenol benzoic acid benzoate salts fig. 24, desirable components recovery versus no. of extraction cycle at water-15 % acetic acid solution, 140o c temperature, 300 rpm agitation speed and 20 min mixing time conclusions it may be concluded that: 1. it was found that water-15 % acetic acid is an active solvent for the catalyst (copper) and desirable component (phenol, benzoic acid, benzoate salts) recovery and to achieve clear phase separation of tar from the aqueous acid. 2. the highest recovery of catalyst (80.2 wt%) was achieved under the conditions of 300 rpm agitation speed, 20 minute agitation time, 140 o c temperature, 4/1 phase ratio (a/o) and 4 extraction cycle. 3. the highest recovery of phenol (89.1 wt%), benzoic acid (90.7 wt%) and benzoate salts (87.3 wt%) was achieved under the condition of 300 rpm agitation speed, 20 minute agitation time, 140 o c temperature, 4/1 phase ratio (a/o) and 2 extraction cycle. references 1. phenol-hooker chemical corp. hydrocarbon processing, nov. 1965, p.256. 2. phenol-scientific design co., inc., hydrocarbon processing, nov. 1965, p. 257. 3. keading w.w., “how dow makes phenol from toluene”, hydrocarbon processing, nov. 1964, p. 173. 4. phenol-universal oil products co., hydrocarbon processing, nov. 1967, p. 234. 5. phenol-b p chemicals ltd., hydrocarbon processing, nov. 1969, p. 214. 6. lam c.t. and shannon d.m., u.s. patent 4,567,157 (jan. 28, 1986). 7. giew d.n. and ollerenshaw i.e. u.s. patent 3,803,247 (apr. 9. 1974). 8. gelbein a.p. and khonsari a.m. u.s. patent 4,277,630 (jan. 7, l981). 9. van geem p.c. and tenuissen a.j.j.m., u.s. patent 4.383.127 (max’ 10, 1983). 10. inoue y. jpn. kokoku tokkvo koho. 64-934 (1989). 11. maki t. and masuvarna t., jpn. kokoku tokkyo koho. 210812 (1990). wadood t. mohammed and sami m. zaboon 17 vol.10 no.3 (september 2009) 12. maki t. and masuyarna t., jpn. kokoku tokkyo koho, 2 10813 (1990). 13. gelbein a.p. and nislic.k a.s., hydrocarbon processing, 57, 125 (1978). 14. stolcova m., hronec m., ilavskv j. and kabesova m., j. catalyst. 101. 153 (1986). 15. stolcova m.. hronec m. and ilavskv i., j. catalyst, 119, 83 (1989). 16. hronec m.. stolco’a m., cvengrosova z. and kizlink j., j. appi. catalyst, 69, 201 (1991). 17. maki takao, masnyama tetsuo, yokoyama toshihara, jp patent 59013743 (1984). 18. maki takao, masnyama tetsuo, jp patent 59029626 (1984). 19. dyckman; arkady samuilovih, u s patent 6,025,530 (2000). 20. lupac compendium of chemical terminology, 2 edition (1997), www.iupac.org/goldbook1s03965.pdf. 21. enviro.nfesc.navymil/erb/restoretion/technologi es/remed/physhemlphc-31.asp (2004). 22. knoor j., u s patent 5,364,978 (1994). 23. zinenkov a., r u patent 2056400 (1996). 24. issakovich, r u patent 2079479 (1997). 25. al-mousawi, a. k., ”extraction of iron from aqueous chloride media in presence of aluminum”, m. sc. thesis, university of baghdad (2005). http://www.iupac.org/goldbook1s03965.pdf iraqi journal of chemical and petroleum engineering vol.18 no.2 (june 2017) 13 25 issn: 1997-4884 preparation of ppsu hollow fiber nanofiltration membranes for nanofiltration application bashir y. sherhan 1 , areej d. abbas 1 , hussein a. alabdly 3 , thamer j. mohammed 2 , qusay f. alsalhy 1 , thamera kidher 4 , lamees h. fahad 4 , hamsa ahmed 4 and remonda h. melkon 4 1 membrane technology research unit, chemical engineering department, university of technology, baghdad, iraq 2 chemical engineering department, university of technology, baghdad, iraq 3 ministry of higher education and scientific research, baghdad, iraq 4 chemical and petrochemical research center, corporation of research and industrial development, ministry of industry and minerals, baghdad, iraq correspondence to: qusay f. alsalhy (e-mail: qusay_alsalhy@yahoo.com; 80006@uotechnology.edu.iq) abstract ppsu hollow fiber nanofiltration membranes are prepared by applying two concentrations and various extrusion pressures according to the phase inversion method. cross-sectional area and outer structures were characterized by using scanning electron microscope (sem) and atomic force microscopy (afm). in additional to the pore size distribution, either the mean roughness or the mean pore size of the ppsu hollow fiber surfaces was evaluated by afm. it was found that the morphology of the ppsu fibers had both sponge-like and finger-like structures through different extrusion pressures and ppsu concentrations. the mean pore size and mean roughness for inner and outer surfaces were seen to be decreased with the increase of extrusion pressure at two different ppsu concentrations. moreover, the lead ion rejection was significantly improved from 19 to 78 % with increasing the extrusion pressure from 2.5 to 3 bar at 25 wt.% ppsu concentration. key words: ppsu, hollow fiber membrane, nanofiltration, morphology, heavy metals removal. introduction although there are more than 124 types of the polymers and most of the traditional polymersused for the preparation of membranes, some of the polymers are still not widely investigated to apply for this purpose such as the ppsu hollow fiber nanofiltration membranes. however, several researchers referred to the use of ppsu for the preparation of membranes for different applications. for example, hwang [1], had improved the permeability of polymer membranes and the efficiency of filtration process throughout the water treatment by means of preparing the novel composite of membranes via adding activated carbon (ac) / university of baghdad college of engineering iraqi journal of chemical and petroleum engineering mailto:qusay_alsalhy@yahoo.com mailto:80006@uotechnology.edu.iq preparation of ppsu hollow fiber nanofiltration membranes for nanofiltration application 14 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net polyethylene glycol (peg) with different ratios into both polyetherimide (pei) polymers and polyphenyl sulfone (ppsu). the results showed that the adding up of ac was affected in a straight line the distribution of pore size, the morphology of membrane, the chemical properties, and the porosity. it also appears that increasing in the ac concentration was guided to improve both the filtration flux and the permeability of membrane (i.e. ac/ppsu/pei/peg composite). alternatively, the addition of hydrophilic pore-formation agent (i.e. peg) can also be led toenhance both the porosity and the surface hydrophilicity of the novel composite of membranes. furthermore, siavash [2], had prepared the ppsu as a result of its prospect utilize in the solvent resistant nanofiltration (srnf) membranes. these membranes had made according to the dry wet spinning method in the midst of three special concentrations of ppsu (22.5%, 25% and 27.5% w/w) with the present of n-methyl-2-pyrrolidone (nmp) as a dope solution. they were cautiously distinguished consistent with their permeability, porosity, morphology, and selective properties. it was discovered that the fiber had a classical asymmetric structure with almost dense skin layer and porous substructure. in addition, an increase in the quantity of macro-voids inside the porous substructure was clearly detected once the concentration of polymer was diminished. whereas, it seems that raising of polymer concentration within the generated dope was caused an increase in the rejection of dyes with a decrease in the permeability of iso-propanol. in terms of improvement the rejection, the membrane is exhibited a typical opportunity for favorable apply in nanofiltration applications, although the permeability is reduced and it therefore needs supplementary optimization. additionally, by measuring the alter in the length of the fiber prior toand subsequent tothe solvent treating for ten days, the effects of the membranes exposure on the acetone, isopropanol, diethyl ether, toluene, n-hexane, and ethyl acetate have been investigated. generally, the stability of membranes was confirmed in most of solvents with the exception of methyl ethyl ketone. the permeability in n-heptane, n-hexane, iso-propanol, ethanol, methanol, toluene and acetone has been analyzed and excluding the last two solvents, the membranes demonstrate an excellent stability during the permeation test. zhong [3], exploited a sulfonated polyphenylene sulfone (sppsu) in order to fabricate a novel positively charged nanofiltration (nf) membranes, which is supported with both fully sponge-like morphology and hydrophilic properties as a result of the employ of uv-induced grafting. the obtained nf membranes molecular weight cut off (mwco) of 1627–1674 da with a high pure water permeability and an effective pore diameter of 1.13–1.20 nm were seen to be successfully developed as a result of employing two dissimilar categories of positively charged grafting monomers. according to the salt rejections results over the novel nanofiltration membranes, it seems to be followed the order of r(mgcl2)4r(nacl)4r(mgso4)4r(na2 so4). a high removal to mgcl2 of up to 95.20% was also acquired. besides, these newly evolved nf1 and nf2 membranes are shown an interesting probability for the elimination of dye from wastewater treatment. siavash [4], also prepared nf flat sheet membranes derived from polyphenylsulfone (ppsu). the synthesis methods depend upon phase http://www.iasj.net/ bashir y. sherhan, areej d. abbas, hussein a. alabdly, thamer j. mohammed, qusay f. alsalhy, thamera kidher, lamees h. fahad, hamsa ahmed and remonda h. melkon -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 15 inversion with three diverse compositions of ppsu (i.e. 17 wt.%, 21 wt.%, and 25 wt.%) in dimethylacetamide (dma), nmethyl-2-pyrrolidone (nmp) and a mixture of dimethylformamide (dmf) and nmp. it was observed that the morphology of membranes has a regular asymmetric structure characterized by a dense skin top layer and a porous substructure. it seems once again, the promoting in the amount of macro-voids within the membrane substructure is created as soon as the polymer concentration is reduced. theperformance of the elaborated membranes was checked by evaluation both permeability of methanol and repudiation of dissolved dye (rose bengal). it was noticed that an increase in the polymer concentration was led to decrease in the methanol permeability, even as a rejection of rose bengal (rb) was enhanced. in addition, by investigating the rejection of rb before and after solvent contact and determining the flux of methanol, the impact of acetone, iso-propanol, diethyl ether, toluene, n-hexane, and ethyl acetate on the membranes has also been studied. in most of these solvents exclusive of acetone and toluene, the membranes were seen to be stable with a dramatically changed in the performance of membranes for both diethyl ether and ethyl acetate, on the other hand a minor effect and higher stability was observed for iso-propanol in n-hexane. hwang [5], had synthesized an antifouling ultra-filtration membrane for humic acid (ha) separation by employing a blending technique using a non-solvent induced phase separation method. in order to figure the ppsu/pei blend membranes, a positively charged/hydrophilic polyetherimide (pei) was in that case blended with negatively charged/hydrophobic polyphenyl sulfone (ppsu). the specifications of membrane surface (i.e. surface charge, roughness, hydrophilicity, and morphology) were tailored according to the blending ratio with the aim of improvement the resistance of the membrane against fouling. for instance owing to the effect of electrostatic repulsion, the blend membranes with a weak negative charge were seen to be had a highquality resistance to the negatively charged ha. the hydrophilic pei is segregated to the membrane/water interfaces with increasing the pei content due to change the surface charge from negative to neutral and constructs a hydrophilic surface. in this study, ppsu hollow fiber nanofiltration membranes are prepared in proportion to the phase inversion method. the effects of two different ppsu concentrations under various extrusion pressures on the morphology of ppsu hollow fibers and their separation performance were neatly investigated. sem and afm techniques were used to characterize the hollow fiber membranes. a lead ion was also utilized to test the performance of the ppsu membranes. experimental work 1. materials polyphenyl sulfone (ppsu) achieving from solvay (belgium) was used as a polymer material. 1-methyl-2pyrrolidone (nmp, 99.5%) was employed as a polymer solvent and provided by sigma-aldrich (germany). pb(no3)2 heavy metals was also utilized to explore the membrane separation performance, which is supplied by bdh (england). 2. ppsu membrane preparation grains of ppsu with concentration of 25 and 29 wt.% were dissolved over http://www.iasj.net/ preparation of ppsu hollow fiber nanofiltration membranes for nanofiltration application 16 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net magnetic stirrer inside 75 and 71 wt.% of nmp solvent, respectively at room temperature for two days. the final homogeneous ppsu solution was transferred to a vertical column and left for 24 h to remove the air bubble from the ppsu solution as shown in figure 1. after that the nitrogen gas was employed to compressed the ppsu solution to the spinneret (polymer feed side) at different extrusion pressures. the water as a bore fluid was pumped at a rate of 3 ml/min by applied precision gear pump (information technology engineering co., gurogu, south korea) to the spinneret (water feed top side) as shown in figure 1. the two fluids were brought in to contact at the exit point of the spinneret and then entered the tap water coagulation bath at 36 °c after air gap distance of 3.5 cm. subsequently, the nascent hollow fiber was drawn with a suitable speed without any starching in the nascent hollow fiber. the produced hollow fiber was kept in the water vessel for 24 h to remove the remaining nmp from the hollow fiber. finally the hollow fiber was treated with glycerol solution for 48 h in order to avoid the structure collapse of the hollow fiber. fig. 1: ppsu hollow fiber membrane spinning system 3. sem measurement one of the powerful techniques for characterization the structural morphology of the membrane is the scanning electron microscope (sem). the structure of the prepared membranes in this work was investigated using sem (model: quanta feng 200, fei company) at the university of technology, baghdad, iraq. in order to measure the cross-section structure, the each membrane sample freezes and breaks in liquid nitrogen, to make a clean and uniform configuration without any damage in the structure of the membranes. with the aim of measuring the structure of the inner and outer surfaces, the membranes were therefore dried under vacuum; and then coated with a thin gold layer by means of a sputter apparatus. http://www.iasj.net/ bashir y. sherhan, areej d. abbas, hussein a. alabdly, thamer j. mohammed, qusay f. alsalhy, thamera kidher, lamees h. fahad, hamsa ahmed and remonda h. melkon -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 17 4. atomic force microscope (afm) measurement with the purpose of measuring the size of pore and the distribution of pore size for the prepared membranes, ppsu hollow fiber membrane samples were introduced to the spacious surface analysis through an atomic force microscope (afm) via contact mode with a suitable silicon tip [angstrom advanced inc. (usa), model aa3000]. measurements involved an evaluation for the topography, the deflection, and the lateral force. a statistical pore size distribution for the surfaces of ppsu hollow fiber membrane has already been established by using imager 4.31 software. 5. preparation of heavy metal solution and ppsu membrane performance in order to study the effect of heavy metal ions concentration on the performance of the ppsu membrane, salts solution was synthesized in single-salt solution of (pb(no3)2 (i.e. concentration of 160 mg of pb(no3)2 with 1000 ml of pure water and that means 100 ppm of lead). before nf experiments of the heavy metals aqueous solutions, the pure water permeability experiment of the ppsu membranes was carried out at a temperature of 25±3 °c and pressure of 1.5 bar for one hour by using the nf system as shown in figure 2. pure water permeability (pwp) kg/(m 2 ·hr.bar) was estimated along with the following equation: pat v pwp   .. …(1) where, v is volume of the collected permeate (l) during time t (hr), a is the effective surface area (m 2 ), and δp is the trans membrane pressure (bar). the nf experiments of heavy metal solution were consequently completed in batch circulation mode. with the purpose of maintaining a constant concentration within feed tank, both permeate and retentate have been returned into the feed tank. the solute separation factor, f, can be calculated by the following equation: …(2) where cfeed and cpermeate are the concentration of the heavy metals ions in feed and streams solution. the concentrations of heavy metals ions within the feed and permeate streams were measured using atomic absorption (spectrometer), perkin elmer 5000. fig. 2: ppsu hollow fiber nanofiltration membrane separation performance experimental system http://www.iasj.net/ preparation of ppsu hollow fiber nanofiltration membranes for nanofiltration application 18 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net results and discussion 1. sem measurement 1.1. outer surface of ppsu hollow fibers to investigate the effects of two different ppsu concentrations and extrusion pressures and in order to study the performance of the ppsu hollow fiber membranes, the outer surface and cross-section of the ppsu hollow fibers were accurately studied using sem analysis. the sem images of the ppsu hollow fiber outer surface are presented in figure 3. it can be seen that the prepared ppsu hollow fiber with 25 wt.% ppsu1 under 2.5 bar extrusion pressure present a rough and dense surface as shown in figure 3a. whereas in figure 3b, it can be observed that the prepared ppsu2 hollow fiber membrane with 25 wt.% under 3.0 bar extrusion pressure at 3 ml/min bore fluid flow rate has a less rough and dense surface in comparison with that in ppsu1. this is due to the formation of aggregates during the fast speed of the hollow fiber within 3.5 cm air gap throughout the formation of the hollow fibers, wijmans [6]. in figure 3c and 3d similar behaviors were observed for two ppsu hollow fiber membranes that prepared from 29 wt.% and under two different extrusion pressures (i.e. 1.5 and 2.5 bar). (a) ppsu125%, 2.5 bar, 3ml (b) ppsu2 25%, 3.0 bar, 3ml (c) ppsu3 29%, 1.5 bar, 3ml (d) ppsu4 29%, 2.5 bar, 3ml fig. 3: sem images of the outer surface of ppsu hollow fiber membranes http://www.iasj.net/ bashir y. sherhan, areej d. abbas, hussein a. alabdly, thamer j. mohammed, qusay f. alsalhy, thamera kidher, lamees h. fahad, hamsa ahmed and remonda h. melkon -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 19 1.2. cross-section of ppsu hollow fibers figure 4 presents the effect of ppsu concentration and extrusion pressure on the cross sectional structure of the ppsu hollow fiber membranes. it can be noticed that the prepared ppsu1 hollow fiber with 25 wt.% ppsu1 under 2.5 bar extrusion pressure has sponge-like structure that appearing at the entire hollow fiber, while there is only a small finger-like structure near the edge of the inner surface of the hollow fiber membrane as shown in figure 4a. besides, it can be observed that the ppsu hollow fiber membrane that prepared from ppsu2 with 25 wt.%, and under 3.0 bar extrusion pressure at 3 ml/min bore fluid flow rate has a little finger-like structure that appearing near from the outer edge of the hollow fiber, whilst there is only a large finger-like layer close to the edge of the inner surface of hollow fiber membrane, as well as there is also a sponge-like structure that growing within the middle of the cross-section as shown in figure 4b. this observation can be attributed to the fast solvent exchange from the polymer solution to the internal coagulation water with enhancing of nascent hollow fiber speed during the formation of membrane, aptel [7] – alsalhy [8]. in figure 4c and 4d, it can be distinguished that the decrease of extrusion pressure from 1.5 bar to 2.5 bar at 29 wt.% ppsu concentration is led to suddenly emerge one layer of finger-like structure near from the inner surface of hollow fiber membrane, which has already been changed to full sponge-like structure. this is maybe owing to the increase of contact time between the polymer solution and coagulation water, which results either to increase the water diffusion or penetration inside the structure of the nascent hollow fiber. (a) ppsu125%, 2.5 bar, 3ml (b) ppsu2 25%, 3.0 bar, 3ml (c) ppsu3 29% 1.5 bar 3 ml min (d) ppsu429%, 2.5 bar, 3ml fig. 4 sem images of the cross section of ppsu hollow fiber membranes http://www.iasj.net/ preparation of ppsu hollow fiber nanofiltration membranes for nanofiltration application 20 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net 2. afm measurement figure 5 shows the 3d and 2d afm images of the inner and outer surfaces of ppsu hollow fiber membrane, which are prepared at different extrusion pressures and two different ppsu contents. it can be recognized that the roughness of the inner surfaces is decreased either with increasing of extrusion pressure from 2.5 to 3.0 bar at 25 wt.% ppsu or with increasing the extrusion pressure from 1.5 to 2.5 bar at 29 wt.% ppsu, as illustrate in table 2. additionally at the same extrusion pressure (i.e., 2.5 bar) with two different ppsu concentration in dope solution (i.e., 25 wt.% and 29 wt.% ppsu), it can be recognized that the mean roughness seems to be decreased with ppsu concentration. regarding the mean roughness of the outer surfaces, it can be said that the mean roughness of the ppsu was decreased for the outer surfaces of every ppsu hollow fibers. however regarding the pore size and the distribution of pore size for ppsu membranes, table 1 also shows the effects of extrusion pressures at two different ppsu concentrations on the mean pore size. it can be noted that the pore size of the inner surfaces of prepared ppsu hollow fiber membrane under 2.5 and 3bar extrusion pressures at 25 wt.% ppsu in dope solution is reduced with raising of extrusion pressure. similar behavior was observed for the pore size of the prepared membrane from 29 wt.% ppsu. moreover, in table 2 is shown that the pore size of outer surface for prepared ppsu hollow fibers under different extrusion pressures and ppsu concentrations has also been diminished with promoting of extrusion pressure. figure 6 shows the effect of extrusion pressure and ppsu concentration in dope solution on the distribution of pore size over inner and outer surface. it can be distinguished that the pore size distribution of the inner surface of the prepared ppsu hollow fibers membrane from 25 wt.%of ppsu under 2.5 bar is between 10 and 110 nm, while the pore size distribution at 3.0 bar turn out to be narrow (about 15 and 70 nm). furthermore, the pore size distribution of the outer surface is in the range of 30 and 130 nm at 2.5 bar, whereas the pore size distribution at 3.0 bar is between 20 and 80 nm. this means that as the extrusion pressure off increases the pore size (inner and/or outer) becomes narrower. in addition, the pore size distribution of the inner surface of ppsu hollow fiber membrane prepared from 29 wt.% at 1.5 bar is within the range of 7 and 110 nm, whilst the pore size distribution at 2.5 bar is between 23 and 90 nm. on the other hand the pore size distribution of the outer surface of the ppsu hollow fibers is about 20 to 100 nm for the prepared membrane from 29 wt.% under 1.5 bar, but the pore size distribution is between 20 and 110 nm under extrusion pressure of 2.5 bar as demonstrated in figure 6. (a) 3d ppsu1 25% 2.5 bar 3 ml/min inner surface http://www.iasj.net/ bashir y. sherhan, areej d. abbas, hussein a. alabdly, thamer j. mohammed, qusay f. alsalhy, thamera kidher, lamees h. fahad, hamsa ahmed and remonda h. melkon -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 21 (b) 2d ppsu1 25% 2.5 bar 3 ml/min inner surface (c) 3d ppsu1 25% 2.5 bar 3 ml/min outer surface (d) 2d ppsu1 25% 2.5 bar 3 ml/min outer surface (e) 3d ppsu2 25% 3 bar 3 ml/min inner surface (f) 2d ppsu2 25% 3 bar 3 ml/min inner surface (g) 3d ppsu2 25% 3 bar 3 ml/min outer surface (h) 2d ppsu2 25% 3 bar 3 ml/min outer surface (i) 3d ppsu3 29% 1.5 bar 3 ml/min inner surface (j) 2d ppsu3 29% 1.5 bar 3 ml/min inner surface (k) 3d ppsu3 29% 1.5 bar 3 ml/min outer surface http://www.iasj.net/ preparation of ppsu hollow fiber nanofiltration membranes for nanofiltration application 22 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net (l) 2d ppsu3 29% 1.5 bar 3 ml/min outer surface (m) 3d ppsu4 29% 2.5 bar 3 ml/min inner surface (n) 2d ppsu4 29% 2.5 bar 3 ml/min inner surface (o) 3d ppsu4 29% 2.5 bar 3 ml/min outer surface (p) 2d ppsu4 29% 2.5 bar 3 ml/min outer surface fig. 5: afm images of the different ppsu hollow fiber membranes table 1: dope compositions and spinning conditions of the fabricated ppsu hollow fibers air gap length (cm) bore fluid flow rate (ml/min) extrusion pressure (bar) coagulation path temperature (˚c) bore fluid composition mnp/water dope composition (wt%) membrane code 3.5 3 2.5 36 0/100 ppsu/nmp: (25:75) ppsu1 3.5 3 3 36 0/100 ppsu/nmp: (25:75) ppsu2 3.5 3 1.5 36 0/100 ppsu/nmp: (29:71) ppsu3 3.5 3 2.5 36 0/100 ppsu/nmp: (29:71) ppsu4 table 2: porosity, thickness, mean pore size and mean roughness of ppsu hollow fibers membrane code thickness (µm) porosity (%) mean pore size (nm) mean roughness (ra)(nm) inner surface outer surface inner surface outer surface ppsu1 77 71 53.82 65.74 6.05 0.433 ppsu2 80 69 37.31 51.40 2.57 0.413 ppsu3 61 62 52.04 49.75 3.42 0.802 ppsu4 63 60 51.73 47.23 2.13 0.513 http://www.iasj.net/ bashir y. sherhan, areej d. abbas, hussein a. alabdly, thamer j. mohammed, qusay f. alsalhy, thamera kidher, lamees h. fahad, hamsa ahmed and remonda h. melkon -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 23 ppsu1 inner ppsu1 outer ppsu 2 inner ppsu2 outer ppsu3 inner ppsu3 outer ppsu4 inner ppsu4 outer fig. 6: pore size distribution of the ppsu hollow fiber membranes 3. ppsu performance table 3 shows the effects of two different ppsu concentrations and various extrusion pressures on both the pure water permeation flux and the heavy metal ion rejection of ppsu hollow fiber membranes. the pure water permeation flux is 2 l.m -2 .h -1 .bar -1 for the ppsu hollow fiber membrane under 2.5 bar, whereas increasing the extrusion pressure to 3 bar, results to an increase in the pure water permeation flux to 5 l.m -2 .h 1 .bar -1 . for the ppus hollow fiber http://www.iasj.net/ preparation of ppsu hollow fiber nanofiltration membranes for nanofiltration application 24 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net membrane prepared from 29 wt. % under 1.5 bar, the pure water permeation flux is 10 l.m -2 .h -1 .bar -1 and it is reduced to 8 l.m -2 .h -1 .bar -1 for ppsu hollow fiber membrane prepared from 29 wt. % ppsu in the dope solution under extrusion pressure of 2.5 bar. this finding can be related to the altering of the ppsu structures during the formation of hollow fiber because of the higher amount of the polymer solution flow out from the spinneret at 2.5 bar, which might be affected by the amount of the solvent/non-solvent exchange rate of internal coagulant within the external coagulation bath. as well, this watching can be attributed to the enlargement in the thickness of the ppsu and diminishing the mean pore size with raising the extrusion pressure as summarized in table 2. table 3: ppsu membrane permeation flux and separation performance membrane code permeate flow (l/ m 2 bar h) cpb in permeate side (ppm) pb rejection (rpb %) ppsu1 5 81 19% ppsu2 2 22 78% ppsu3 10 76 24% ppsu4 8 84 16% these results were agreed with that reported by alsalhy [9], alsalhy [10]. likewise from table 3, it can be perceived that there is a significant improvement in the lead ion rejection of the ppsu hollow fiber membranes with an increase in the extrusion pressure from 2.5 bar to 3 bar during the formation of the nascent hollow fiber that composed of 25 wt.% ppsu in dope solution. the pb + rejection seems to be improved from 19 to 78% as a result of enhancement the extrusion pressure. finally, using 29 wt.% ppsu concentration in the dope solution was caused a reduction in the pb + rejection from 24 to 16 % as the extrusion pressure was elevated from 1.5 to 2.5 bar. this is observation can be attributed to the lower of extrusion pressures in case of 29 wt.% ppsu hollow fiber with reference to that hollow fiber prepared from 25 wt.% ppsu under extrusion pressures of 2.5 and 3 bar, which essentially leads to decrease in the thickness of the hollow fiber, and successively guides to decrease in the pb + rejection. conclusions preparation of different ppsu hollow fiber nf membranes for heavy metals removal results to several conclusions, which can be summarized as follows:  ppsu hollow fiber prepared with 25 wt.% ppsu and under extrusion pressure of 2.5 bar present a less rough and dense outer surface in comparing with that prepared under extrusion pressure of 3 bar.  different cross sectional structure was observed for all ppsu hollow fiber membranes most of them similar to the sponge structure.  the mean roughness and mean pore size for inner and outer surfaces of hollow fiber membranes were seen to be decreased with increasing the extrusion pressure at two different ppsu concentrations.  the lead ion rejection was extensively improved from 19 to 78 % with the altitude of extrusion pressure from 2.5 to 3 bar at 25 wt.% ppsu concentration. acknowledgment we would like to introduce our kindly acknowledgment to the chemical and petrochemical research center, http://www.iasj.net/ bashir y. sherhan, areej d. abbas, hussein a. alabdly, thamer j. mohammed, qusay f. alsalhy, thamera kidher, lamees h. fahad, hamsa ahmed and remonda h. melkon -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 25 company of research and industrial development, ministry of industry & minerals in baghdad/iraq for supporting this research. references 1hwang, li-luen., jyh-cherng, chen., and ming-yen, wey., (2013), "the properties and filtration efficiency of activated carbon polymer composite membranes for the removal of humic acid", desalination, 313, pp.166-175. 2siavash, d., franco, t., johannes, c. j., elena, t., fabio, b., paola, b., patricia, l., jan, d., enrico, d., and bart van der, b., (2011), "preparation of solvent stable polyphenylsulfone hollow fiber nanofiltration membranes", journal of membrane science, 384, pp. 89– 96. 3zhong, p. s., natalia, w., taishung, c., martin, w., and christian, m., (2012), "positively charged nanofiltration (nf) membranes via uv grafting on sulfonated polyphenylenesulfone (sppsu) for effective removal of textile dyes from wastewater", journal of membrane science, 417– 418, pp. 52–60. 4siavash, d., johannes, c., jansen, franco, t., elena, t., patricia, l., jan d., enrico, d.c, and bart van der, b., (2011), "novel polyphenylsulfone membrane for potential use in solvent nanofiltration", journal of membrane science, 379, pp. 60– 68. 5hwang, li-luen., hui-hsin, t., and jyh-cherng, c., (2011), "fabrication of polyphenylsulfone /polyetherimide blend membranes for ultrafiltration applications: the effects of blending ratio on membrane properties and humic acid removal performance", journal of membrane science, 384, pp. 72– 81. 6wijmans, j.g.; baaij, j.p.b.; and smolders, c.a., (1983), "the mechanism of microporous or skinned membranes produced by immersion precipitation", j. membr. sci., 14, 263. 7aptel, p.; abidine, n.; ivaldi, f.; and lafaille, j.p., (1985), "polysulfone hollow fibers: effect of spinning conditions on ultrafiltration propertie", j. membr. sci., 22, 199. 8alsalhy, q. f., (2013), "influence of spinning conditions on the morphology, pore size, pore size distribution, mechanical properties, and performance of pvc hollow fiber membranes", sep. sci. and techn., 48, pp. 234-245. 9alsalhy, q. f., salih, h.a., melkon, r. h., mahdi, y. m., and abdul karim, n. a., (2014), "effect of the preparation conditions on the morphology and performance of poly (imide) hollow fiber membranes", journal of applied polymer science, 131, 40428, pp.1 11. 10alsalhy, q. f., salih, h.a., silvia, s., figoli, a., zablouk, m., and drioli, e., (2014), "poly (ether sulfone) (pes) hollow-fiber membranes prepared from various spinning parameters", desalination, 345, pp. 21-35. http://www.iasj.net/ iraqi journal of chemical and petroleum engineering vol.15 no.2 (june 2014) 914 issn: 1997-4884 using sonic log to predict abnormal pressure zones in selected oil wells (western of iraq) talib a. saleh petroleum engineering department, college of engineering, university of baghdad abstract two oil wells were tested to find the abnormal pressure zones using sonic log technique. we found that well abu-jir-3 and abu-jir-5 had an abnormal pressure zones from depth 4340 to 4520 feet and 4200 to 4600 feet, respectively. the maximum difference between obtained results and the field measured results did not exceed 2.4%. in this paper, the formation pressures were expressed in terms of pressure gradient which sometimes reached up to twice the normal pressure gradient. drilling and developing such formations were dangerous and expensive. the plotted figures showed a clear derivation from the normal trend which confirmed the existence of abnormal pressure zones. keywords: normal pressure, subnormal pressure, abnormal pressure, formation pressure, formation pressure gradient, transition zone introduction abnormal pressures have been identified in about 180 sedimentary basins and most oil and gas generation in such basins occurs within the over0pressured fluid compartments [1]. knowledge of the pressure distribution in a given area frequently minimizes the problems associated with all phases of operation: geophysics, geological, drilling and petroleum engineering. certainly, the most serious problem met by the group of oil well drilling is that of abnormal pressure zones. this problem is related to tertiary geological age and it has, as mentioned before, a direct relation to geophysical prospecting, geological structures and petroleum engineering. generally, normal pressure is considered with formation pressure which is approximately equal to hydrostatic head of water column if the formation is opened to the atmosphere and this is equal to 0.465 psi/ft which is called pressure gradient (p.g) while abnormal pressure zones are those which have (p.g) more than 0.465 psi/ft [2]. it may reach twice of this value as observed in the north sea. working with such formations is hazardous and very expensive [3]. it is interesting to mention that there is an upper transition zone through which there are indications of existence of abnormal pressure zone. studies in petroleum industry showed that the rate of penetration is reduced by an increase in the mud iraqi journal of chemical and petroleum engineering university of baghdad college of engineering using sonic log to predict abnormal pressure zones in selected oil wells (western of iraq) 10 ijcpe vol.15 no.2 (june 2014) -available online at: www.iasj.net column pressure [4]. as we go deeper and deeper the penetration rate is decreased because we will be met by harder rocks. this trend has been reversed through drilling over pressured zones and the pressure gradient will be largely increased [5]. in other words, in an abnormal pressure zones, the mud weight should be increased to balance the formation pressure. many studies showed that the shale density and/or resistivity can be used to detect the over pressured zone [6, 7, 8]. the geological section of the studied area is shown in fig.1 and the location map of the studied area is shown in fig.2 in this work, we have applied the sonic log techniques at selected wells which gave accurate results compared with field data. causes of abnormal pressure 1very rapid deposition of large quantities of sands and shale predominating may result in sand bodies that are completely surrounded by shale and as compaction progressives, water is unable to escape and this give an abnormal pressure zone especially if the rock still has sufficient tensile strength [9]. 2abnormal pressure refers to areas of high topographic relief where the outcrop of the pressured sand acts as an elevation high enough to cause artesian head; this is especially true in rapid filling (tertiary) sedimentary basins [10]. 3thick gas cap at the interface of water/gas is caused by growth faults [11]. 4fluid transfer is due to the alteration of montmorillonite to illite [12]. 5routes of communication between beds having different pressures are available [12]. 6there are other miscellaneous causes such as reverse osmosis which is the movement of ions in water down a water concentration gradient (i.e. from fresh to saline). the ions will continue to move until the salinities balance or pressure prevents further movement. that pressure is postulated to be as much as 4000 psi in the subsurface where shales can act as the semipermeable and mineral decomposition such as the transformation of gypsum to anhydrite (caso4.2h2o to caso4) and the release of water of crystallization [11, 12]. results and discussion the data and the results concerned with the wells abu – jir3 and abu – jir5 are listed in table1 and table2, respectively. figure1 shows a typical log tsh versus depth of well abu – jir3. the normal curve was constructed on the log and deviation of tsh from the normal trend clearly began at about 4340 feet which was the depth at which abnormal pressure started. in this well, a normal pressure gradient of 0.465 psi/ft was measured and was increased in the adjacent shales (from depth 4360 to 4520 feet). the normal tsh curve began at 60sec/ft at depth equal to 4320 feet and decreased logarithmically to 15sec/ft at 4520 feet. in the same concept, figure4 shows abnormal pressure zone from depth 4200 to 4600 feet. a correlation was made from sonic log data relating the difference tsh observed and tsh in normally pressured zones to the formation pressure gradient, as shown in figures 5 and 6, respectively. from these figures, an estimation of the formation pressure gradient and as a result formation pressure at any depth may be obtained. talib a. saleh -available online at: www.iasj.net ijcpe vol.15 no.2 (june 2014) 11 conclusions 1the use of the sonic log to detect the beginning of abnormal pressure zone was applied with good results in the studied area. 2the interval transit time recorded by sonic log might be thought of as function of lithology and porosity. in other words, since the porosity of the shales decreased with compaction, tsh should decrease with depth. this was shown in figures 3 and 4. 3plotting of pressure gradient with difference in tsh and equivalent mud weight (figures 5 and 6) could be used to evaluate a given drilling objective through determining mud weight and hence casing requirements at any depth. references 1hunt, j. m.: "generation and migration of petroleum from abnormally pressured fluid compartments", aapg bulletin, v.74, no.1, pp. 1-12, january, 1990. 2prestel, a., and memok.: "estimation of formation pressure", jour.pet.tech., pp.717-723, june, 1978. 3herring. e.; "estimating abnormal pressures from log data hi the north sea", presented at the second annual "j meeting of the spe of aime, london, england, april, 1973. 4tomson, j.: "application of drilling data to over pressure detection", jour. pet. tech., pp.1387-1391, nov., 1979. 5myer, l.: "measuring and using shale density to aid in drilling wells of high pressure", j.p.t, 1423-1425, nov. 1982. 6hottman, c, and johnson, r.: "estimation of formation pressure from log-derived shale properties", jour. pet. tech., june, 1965. 7morris, r., and biggs, w.: "using log-derived values of water saturation and porosity", spwla symposium, 1967. 8burke, j., campbell, r., and schmidt, a.: "the litho-porosity crossplot", the log analyst spwla, nov.-dec., 1969. 9hussien, m. and kolb, l.: "geological significance of abnormal pressure formation", j.p.t, pp.961-963, august, 1994. 10jeorge, k., and selman, n.: "water production from abnormal pressure formations", j.p.t., pp. 317-32, august, 1993. 11kavach, n., and talib, a.: "some aspects of abnormal pressure zone", j.p.t., pp.212-218, nov., 1995. 12pettijohn, f., "sedimentary rocks," harper and brothers, new york, 1957, (second edition). 13sissakian, v.k. 2000: geological map of iraq. 14mahmoud a. als'adi, ph.d thesis 2010(formation evaluation of abo-jir field) western iraq. 15final well reports (abo-jir field). using sonic log to predict abnormal pressure zones in selected oil wells (western of iraq) 12 ijcpe vol.15 no.2 (june 2014) -available online at: www.iasj.net fig. 1: geolgoical section of the studied area (after sissakian , 2000) fig. 2: location map of the studied area talib a. saleh -available online at: www.iasj.net ijcpe vol.15 no.2 (june 2014) 13 table 1: well abu – jir 3 pressure estimation from sonic log data depth ft t nor. µsec/ ft tobs. µsec/ft tobs. tnor. f.p.g pressure psi equivalent mud weigh p.p.g 4320 60 60 0 0.465 2008.8 8.937 4340 50 50 0 0.465 2081 8.937 4360 40 50 10 0.6 2616 11.533 4380 40 55 15 0.62 2715.6 11.916 4400 30 60 30 0.83 3652 15.952 4420 25 65 40 0.93 4110.6 17.875 4440 23 70 47 0.94 417306 18.067 4460 20 60 40 0.93 4147.8 17.875 4480 17 40 23 0.81 3628.8 15.568 4500 15 45 30 0.88 3735 15.953 4520 15 35 20 0.80 3616 15.568 table 2: well abu – jir 5 pressure estimation from sonic log data depth ft t nor. µsec/ ft tobs. µsec/ft tobs. tnor. f.p.g pressure psi equivalent mud weigh p.p.g 3700 300 300 0 0.465 1720.5 8.937 3750 250 250 0 0.465 1743.75 8.937 3800 150 150 0 0.465 1767 8.937 3850 210 210 0 0.465 1790 8.937 3900 190 190 0 0.465 1813.5 8.937 3950 200 200 0 0.465 1836.75 8.937 4000 190 190 0 0.465 1860 8.937 4050 180 180 0 0.465 1883 8.937 4100 150 150 0 0.465 1906.5 8.937 4150 145 145 0 0.465 1929.75 8.937 4200 110 120 10 0.6 2520 11.532 4250 110 150 40 0.93 3922 17.367 4300 105 155 50 0.44 4042 18.067 4350 100 160 60 0.9345 4065 17.961 4400 95 170 75 0.942 4144.8 18.105 4450 85 155 70 0.935 4140.75 17.884 4500 77 130 53 0.941 4234.5 18.086 4550 72 110 38 0.91 4140.5 17.490 4600 68 100 32 0.89 4094 17.106 fig. 3: pressure estimation from sonic log data using sonic log to predict abnormal pressure zones in selected oil wells (western of iraq) 14 ijcpe vol.15 no.2 (june 2014) -available online at: www.iasj.net fig. 4: pressure estimation from sonic log data fig. 5: relationship of (pressure gradient, travel time and equivalent mud weight) in abu – jir 3 fig. 6: relationship of (pressure gradient, travel time and equivalent mud weight) in abu – jir 5 removal of dissolved cadmium ions from contaminated wastewater using raw scrap zero-valent iron and zero valent aluminum as locally available and inexpensive sorbent wastes available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.19 no.4 (december 2018) 39 –45 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: ayad a.h. faisal, email: ayadabedalhamzafaisal@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. removal of dissolved cadmium ions from contaminated wastewater using raw scrap zero-valent iron and zero valent aluminum as locally available and inexpensive sorbent wastes hayder m. rashid and ayad a.h. faisal university of baghdad / environmental engineering department abstract the current study was to examine the reliability and effectiveness of using most abundant, inexpensive waste in the form of scrap raw zero valent aluminum zvai and zero valent iron zvi for the capture, retard, and removal of one of the most serious and hazardous heavy metals cadmium dissolved in water. batch tests were conducted to examine contact time (0-250) min, sorbent dose (0.25-1 g zvai/100 ml and 2-8 g zvi/100 ml), initial ph (3-6), pollutant concentration of 50mg/l initially, and speed of agitation (0-250) rpm . maximum contaminant removal efficiency corresponding to (90 %) for cadmium at 250 min contact time, 1g zvai/ 6g zvi sorbent mass ratio, ph 5.5, pollutant concentration of 50 mg/l initially, and 250 rpm agitation speed were obtained. langmuir and freundlich isotherms were presumed to fit the batch kinetics data for the sorption of cd(ii) onto zvai and/or zvi and found that langmuir (i) was the most representative model type with coefficient of determination r 2 greater than 0.9115. kinetics data for the sorption of cd(ii) onto zvai/zvi mixture and due to the good agreement between the fitted and the experimental results; the data was found to obey the pseudo second order model. the scanning electron microscopy (sem) for the zvi and zvai was conducted before and after the sorbent-liquid reaction and revealed distinct morphological changes in the sorbent surface due to the contaminant saturation and pore channel blockages that ceased the sorption process. keywords: cadmium, zvi, zvai, langmuir, sem, equilibrium received on 30/05/2018, accepted on 25/06/2018, published on 30l12l2018 https://doi.org/10.31699/ijcpe.2018.4.5 1introduction the echo system nowadays suffers in nature from the drastic and devastating impacts resulted from the direct/indirect disposal of the most toxic heavy metals that due to their higher relative density are capable of penetrating and percolating down the unsaturated soil towards the most vital water resource (groundwater) and contaminate it error! reference source not found.. rather than the contamination resulted from the natural activities, the anthropogenic sources also contribute to such contamination error! reference source not found., error! reference source not found., these sources comprise the illegal midnight damping, ust leakages, improper disposal of drums of hazardous wastes, uncontrolled incineration, and discharging of heavy metal based liquid wastes into other territories ‎[4] of the most common problems encountering the ecosystem pollution is the widespread contamination of surface water and groundwater with heavy metals. these metals are defined as metallic elements that have a relatively high density compared with water. in addition to the arsenite, zinc, lead, mercury, cobalt, chromium heavy metals, cadmium is one of the most hazardous species that easily damage the human organs ‎[5], this metal has had higher tendency to accumulate kidney tissues when accidentally ingested ‎[6], error! reference source not found.. during the 60's, the passive in situ remedial technique of pump and treat was used to remove the heavy metals from contaminated groundwater error! reference source not found., error! reference source not found. due to ongoing accumulation of contaminants and its effectiveness during the later stages of the remedial process; this technique was limited for the contaminant recovery only ‎[10]. a promising in situ remedial technology such as prb has recently emerged to use sequenced sorbent materials ‎[11], ‎[12] or mixed sorbents ‎[13]. different materials such as peat, coconut shells, corns, red mud, waste fillers, workshop scrapes of iron and aluminum, etc., have been proposed to construct the matrix of the prb. different ex-studies are analogous in principle to this study such as ‎[14] for the investigation of silty-clay soils as reactive medium for the sorption of cadmium ‎[15] conducted a batch study using zero valent iron as a reactive medium for the removal of high level cadmium from groundwater, ‎[16] studied the biosorption of cadmium onto lechuguilla biomass, ‎[17] investigated the feasibility of using a mixture of activated sludge with zvi for the removal of cadmium from contaminate groundwater, error! reference source not found. https://doi.org/10.31699/ijcpe.2018.4.5 h. m. rashid and a. a.h. faisal / iraqi journal of chemical and petroleum engineering91,4 (2018) 39-45 04 investigated the removal of red dye and cadmium from wastewater using ckd, error! reference source not found. used a mixture of zvi and zvai at optimum conditions for the removal of dissolved heavy metals. the object of this study was to decontaminate cadmium based wastewater using other abundant and inexpensive wastes such as zvi and zvai scrap wastes produced from certain workshops in baghdad and other governorates; the sustainability aims to ease the overburden of such waste materials on the disposal sites and using them for longtime capture of cadmium to prevent it from being spread further distances and contaminate the water resources. the remedial process was to utilize optimum conditions and proper sorbent mass ratios resulted from a batch study to achieve maximum removal efficiency of the dissolved cd (ii). 2experimental work 2.1 materials certain quantities of zvi and zvai scrap wastes have been collected from different commercial workshops in baghdad; these proposed sorbents were separated from other foreign matters such as splinters, dirt, stubs, hairs, etc., the sorbents were crushed, pulverized, and sieved using vibratory sieve 75 mesh number and the sieved particles were finally prewashed using 0.1 m h2so4 solution for 10 min for the preparation of zvi and 10 ml concentrated hci solution for 20 min for the preparation of zvai (lien and wilkin, 2004). a sample of wastewater was prepared by contaminating deionized water with 2.1 g cd(no3)2 dissolved in 250 ml of deionized water and kept at room temperature of (25ºc). the ph of the prepared solution was varied using 0.1 m naoh or 0.1 m hno3 to obtain different values of ph (36). 2.2. batch tests based on fixed temperature of 25 o c, several batch experimental parameters of contact time (0-250) min, initial ph (3-6), initial concentration (50-250) mg/l cd(ii), different zvi/zvai dosage ratios (g/g) per 100 ml, and agitation speed (50-250) rpm were investigated on the removal of this contaminant. different masses of 0.25, 0.50, 0.75, and 1.00 g zvai and 2, 4, 6, and 8 g zvi were placed into 100 ml of 50 mg/l cadmium solution contained in 250 ml flasks. different agitation speeds of (0250) rpm were used to vigorously shake the solid-liquid solution using shaker incubator type daiki, korea. an aliquot of 20 ml was withdrawn and filtered to measure the residual concentration of heavy metal left in aqueous solution. a sample of 10 ml of filtrate was withdrawn and measured for the concentration of dissolved metal ion using aas flame (type shimadzu, japan).the number of cadmium milligrams captured by 1 g sorbent is given by eq.(1): ( ) (1) 3results and discussion 3.1. sorbent selectivity a number of batch experiments were conducted to examine the reliability and effectiveness of zvi and zvai at optimum conditions and varied ph values to achieve the desired removal efficiency: 1the sorption of cd(ii) onto zvi at different ph values revealed a 57% removal of cadmium at ph 5 as shown in fig. 1 2the sorption of cd (ii) onto zvai at different ph values revealed a 88% removal of cadmium using 1 g zvai/ 100 ml at ph 5.5 as shown in fig. 2. the replacement of the zvi by zvai revealed good removal enhancement fig. 1. sorption of cd(ii) onto zvi at different values of ph h. m. rashid and a. a.h. faisal / iraqi journal of chemical and petroleum engineering91,4 (2018) 39-45 04 fig. 2. sorption of cd(ii) onto zvai at different values of ph 3.2. equilibrium time a time interval of (50-250) min was used as contact time for the batch experiments. the driving force for the mass transfer has already ceased when a state of equilibrium was satisfied. fig. 2 revealed a stabilization for the equilibrium concentration beyond 200 min and up to 250 min for the sorption of cadmium onto (0.25-1) g zvai at different ph values; this is due to the surface coverage by cadmium that has almost blocked most of the pore channel; therefore no further vacant sites were available to receive more cadmium ions that rendered the rate for the contaminate concentration approaches zero; this rate attains its maximum value during the first stages of the sorption process since no more active sites were fresh and available. the contact time for the removal of 88% of the cadmium was already determined as 250 min which is set as a reference contact time for other experiments. 3.3. initial ph the ph experimental parameter is considered as significant and sensitive for the dissolution or precipitation of heavy metals in water. different values of ph values in the range of (3-6) were adjusted for the sorption of cadmium onto zvi and/or zvai corresponding to 50 mg/l contaminant initial concentration and different times of contact at temperature of 25 ◦ c. fig. 3 revealed maximum sorption capacity within ph (5-5.5) to yield maximum removal efficiency of 88% for ph less than 4, more protons h + were available to compete with cadmium for the adsorption over the sorbent surface while at ph greater than 4, the protons were eliminated and such completion subsided to cause an increase in the removal efficiency. fig. 3. effect of initial ph on the removal of cd(ii) from aqueous solution 3.4. effect of sorbent dosage the individual masses or combination of zvi and zvai were investigated for the removal of cadmium at the best experimental batch conditions of ph 5.5, 50 mg/l initial contaminant concentration, and 250 rpm agitation speed to achieve maximum removal efficiency. different sorbent dosages of (2-8) g zvi and (0.25-1) g zvai per 100 ml of aqueous solution were used in this regard and found out that the higher removal efficiency is always associated with the higher sorbent dosage. obviously, the higher dosage provides larger number of active sorption sites for the capture of this heavy metal species; furthermore, any further increase in the sorbent mass would promote surface coverage by the contaminant itself and hence stabilizes the removal efficiency. 3.5. effect of initial contaminant concentration a concentration range of (50-200) mg/l cadmium ions were prepared to investigate the relationship between h. m. rashid and a. a.h. faisal / iraqi journal of chemical and petroleum engineering91,4 (2018) 39-45 04 initial concentration of the contaminant and the removal efficiency. fig. 4 depicted the inverse relationship between the initial contaminant concentration and the corresponding removal efficiency i.e., the higher the initial concentration, the lower the removal efficiency is associated, the figure also showed removal efficiencies of 88, 83, 75, and 43% corresponding to 50, 100, 150, 200 mg/l respectively. it is evident that maximum driving force is attained for the solute transport from the higher concentration at the bulk solution to the lower concentration at the sorbent surface; therefore, maximum removal efficiency is always accompanied with higher initial concentration. 3.6. effect of agitation speed different agitation speeds of (0-250) rpm were investigated on the removal efficiency of cadmium ions at fixed experimental parameters; ph 5.5, 50 mg/l initial contaminant concentration, and 250 min contact time. the removal efficiency is directly proportional to the agitation speed in such a way that no cadmium removal is achieved when no agitation is induced while 88% of cadmium was removed corresponding to agitation speed of 250 rpm as shown in fig. 5; this elucidates the most probable decrease in the thickness of the boundary layer surrounding the sorbent solid phase (nernst film) which is in nature exhibits some resistance to the solute transport and hence causing maximum concentration gradient and additional mass loading from the bulk solution to the solid phase medium. 3.7. sorption kinetics sorption is generally influenced by intra particle diffusion and physicochemical processes error! reference source not found.. table 1exhibited the batch experimental kinetics for the sorption of cadmium ions onto the best mass ratio of the sorbent mixture zvai/zvi and optimum conditions. rather than the fitted pseudo first order kinetics model eq.(2), the last two columns of the table have revealed good agreement between the fitted pseudo second order model eq.(3) and the experimental data. these equations have been linearized and fitted for the kinetics data for the sorption of cadmium ions and the constants for best equation, i.e. pseudo second order model, are summarized in table 2 ( ) (2) ( ) (3) table 1. kinetics data for the sorption of cd(ii) onto zvai/zvi mixture at optimum ph 5.5,250 min contact time,50 mg/l initial metal concentration, and 250 rpm agitation speed time (min) ce (mg/l) cs (mg/g) 50 25 0.3571 100 13 0.5286 150 9 0.5857 200 7 0.6143 250 5 0.6428 table 2. constants corresponding to the pseudo second order for the cd(ii) sorption onto the zvai/zvi mixture metal parameter value cd(ii) cse(mg/g) 0.6430 k2 (g/mg min) 0.0960 r 2 0.9652 results proved that the sorbed amount at equilibrium for the pseudo second order kinetics of cadmium was equal to 0.603 mg/g and this value was almost as close as the experimental 0.6428 mg/g. the results have elucidated that the chemisorptions is the most predominant mechanism for the sorption process under consideration. fig. 4. effect of initial concentration on the removal efficiency of cadmium ions onto zvai at ph 5.5, 50 mg/l initial contaminant concentration, and 250 min contact time h. m. rashid and a. a.h. faisal / iraqi journal of chemical and petroleum engineering91,4 (2018) 39-45 04 fig. 5. effect of agitation speed on the removal efficiency of cadmium ions onto zvai at ph 5.5, 50 mg/l initial contaminant concentration, and 250 min contact time 3.8. selection of the best zvi/zvai mass ratio the mixing up of certain amounts of zvi and zvai has positive effect on the removal efficiency as shown in fig. 6 different proportions were roughly examined such that the equilibrium concentrations of the cadmium ions as a function of contact time for different proportions of zvai and zvi were plotted. it is clear that the concentration has dropped from 50 to 28 mg/l to yield a removal efficiency of 44% using 0.75 g zvai/ 5 g zvi per 100 ml, while dropped to 5 mg/l to yield a removal efficiency of 90% using 1 g zvai/ 6 g zvi per 100 ml. the best mass ratio was found to be 1 g zvai and 6 g zvi (equivalent to the 14% zvai and 86% zvi) corresponding to contact time of 250 min, ph of 5.5 and agitation speed of 250 rpm for initial contaminant concentration of 50 mg/l. fig. 6. variation of equilibrium cd(ii) concentration as a function of contact time using different proportions of zvai / zvi 3.9. sorption isotherms for cadmium uptake at fixed temperature, sorption relationships relating the number of milligrams of contaminant captured onto 1 g of sorbent to the cadmium concentration at equilibrium in the form of mathematical or empirical equations is called isotherms ‎[20]. many sorption isotherms such as hill de boer, temkin, kesiliv, elovich, etc., were performed by many researchers and the two most well-known isotherms are the langmuir and freundlich. based upon the experimental sorption data, different forms of langmuir i, ii, iii, and iv as well as freundlich were proposed to investigate which one to well fits these data and according to the to the highest coefficient of determination (r 2 ). table 3 presents the linearized forms of freundlich and langmuir isotherm model. table 3. linearized forms of freundlich and langmuir isotherm models used in the present study for the describing the uptake of cd(ii) onto zvai and zvi model isotherm linearized formula r 2 freundlich 0.3209 langmuir (i) ce/cs = (1/ab) + (1/a) ce 0.9115 langmuir (ii) 1/cs = (1/ab)(1/ce) + 1/a 0.4034 langmuir (iii) cs = a – (1/b)(cs/ce) 0.0835 langmuir (iv) cs/ce = ab – b cs 0.0852 3.10. sem analysis one of the most necessary analyses to conduct comparisons over what was going on before and after the cadmium sorption onto the sorbing media, the scanning electron microscopy (sem) has turned up to depict such comparisons to reveal the surface shape, particles distribution, contaminant distribution, morphological changes, etc., fig. 7 depicted the sem images for the zvi and zvai before and after the reaction with cadmium ions. the 500 times magnified sem images fig. 7 have revealed the followings: a. before the reaction, the nature of the zvi surface was characterized by rough homogenous texture with tremendous number of pore channels to considerably increase the sorption of contaminants and entrap them deep into these channels of the active sorption sites. b. the reaction, the nature of the zvi surface was characterized by almost smooth homogenous texture with highly blocked channels and surface saturation of traces of contaminants in white color. the sorption; as a result; has considerably been reduced such that no more contaminants are sorbed thereafter. c. before the reaction, the nature of the zvai surface was characterized by extremely smooth homogenous texture of remarkable abrupt change in surface morphological shape with descending grooves that have seemingly responsible for the sorption of contaminants. d. after the reaction, the nature of the zvai surface was characterized by groovy lumped and rough texture with remarkable traces of whitish color contaminants sorbed that almost covered the zvai surface and due to such coverage, the sorption consequently reduced. h. m. rashid and a. a.h. faisal / iraqi journal of chemical and petroleum engineering91,4 (2018) 39-45 00 fig. 7. sem images for the zvi (top) and zvai (bottom) sorbents before and after the reaction with cd (ii) 4conclusions 1the cadmium sorption over zvi and/or zvai has significantly been influenced by a set of batch experimental tests to determine the optimum batch experimental parameters to achieve maximum removal efficiency. these parameters included the initial contaminant concentration, contact time, initial ph, sorbent dosage, agitation speed corresponding to 50 mg/l, 250 min, 5.5, 1 g zvai/ 6 g zvi per 100 ml, and 250 rpm respectively to achieve 88% cd(ii) removal. 2the sorption of cadmium onto individual sorbent of either zvi or zvai proved lower insignificant removal efficiency when compared with mixing up these sorbents i.e., a mass ratio of 1 g zvai/ 6 g zvi was the best to achieve 90% cd(ii) ions removal rather than using 0.75 g zvai/ 5 g zvi to yield 44% cd(ii) ions removal among several investigations over different sorbent mass ratios. 3the langmuir (i) was found to well represent the kinetics data for the sorption of cadmium ions onto the zvai/zvi composite sorbent and at the best batch experimental conditions with coefficient of determination (r 2 ) greater than 0.9115; the langmuir sorption constants were (0.307-6.34) mg/g as maximum sorption capacity and (0.19-1.54) l/mg as sorption affinity. references [1] samonski b., hee k., huwa h. , 2005, "heavy metals pollution, sources, impact, receptors", lecture notes published by the civil and environmental engineering, university of portland state, portland, usa. [2] alloway, b. j., zhang, p., mott, c., smith, s. r., chambers, b. j., nicholson, f. a., calton-smith, c., & andrews a. j. (2000), " the vulnerability of soils to pollution by heavy metals", final report for maff project no. sp0127, london: maff. [3] fuge, r., o. selinus, b. alloway, j. a. centeno, r. b. finkelman, r., u. lindh, & p. smedley, 2005, anthropogenic sources. chap 3, "essentials of medical geology", pp. 43–60, amsterdam: elsevier [4] watts j. richard, 2009, "hazardous wastes, sources, pathways, receptors", department of civil and environmental engineering, university of washington, isbn 0-471-00238-0, ny, usa [5] c. pellerin and s. m. booker, 2000, "reflections on hexavalent chromium: health hazards of an industrial heavyweight", environ health perspect, 108(9): a402-a407, pmid 11017901. [6] max costa and catherine b., 2008, " toxicity and carcinogenicity of chromium compounds in humans", critical reviews toxicology, pp155-163, online publication; 10 oct 2008. [7] francois baruthio, 1992, "toxic effects of chromium and its compounds", biological trace element research, vol. 32, pp. 145-153 [8] douglas m. mckay and john a. cherry, 1989, " groundwater contamination: pump-and-treat remediation", environ. sci. technol., 1989, 23 (6), pp 630–636. [9] e. a. voudarias, 2001, " pump-and-treat remediation of groundwater contaminated by hazardous waste", global nest: the int. j. vol 3, no 1, pp 1-10, 2001, department of environmental engineering, demokritus university of thrace, greece. [10] eric m. labolle and graham e. fogg, 2001," role of molecular diffusion in contaminant migration and recovery in an alluvial aquifer system", transport in porous media, vol. 42, pp.155179. [11] d. h. philips, 2009, "permeable reactive barriers: a sustainable technology for cleaning contaminated groundwater in developing countries", desalination, vol. 248, pp. 352-359. [12] a. erto, a. lancia, i. bortone, 2011, "a procedure to design a permeable adsorptive barrier (pab) for contaminated groundwater remediation", journal of environmental management, vol.92, pp. 23-30 [13] janthawan w., sacha j.m., elizabeth h.b., 2005,"natural and waste materials as metal sorbents in prb's", environmental chemistry letters, vol. 3, pp. 19-23 [14] chia m. chang, wang k., chang m., and chen r., 2001,"transport modeling of copper and cadmium with linear and non linear retardation factors ", journal of chemosphere, vol. 43, pp. 1133-1139. [15] lien h.l. and wilkin r.t., 2004, "high level arsenite removal from groundwater by zero valent iron", chemesphere [16] j. romero-gonzales, j. c. walton, j. r. pelarta, e. rodriguez, j. romero, 2009, "modeling the adsorption of cr(iii) from aqueous solution onto agave lechuguilla biomass: study of the advective and dispersive transport", journal of hazardous materials, vol. 161, pp. 360-365. [17] shaban a. and abd al aziz y., 2015, "removal of cadmium and red dye from simulated wastewater by adsorption onto cement kiln dust", phd thesis, university of baghdad, department of environmental engineering [18] yidong zou, xiangxue wang, ayub khan, pengyi wang, 2016, " environmental remediation and application of nanoscale zero-valent iron and its composites for the removal of heavy metal ions: a review", environ. sci. technol., 2016, 50 (14), pp 7290–7304 [19] sharwan k., timothy g., david mazyck, 2012, "equilibrium and intraparticle diffusion of stabilized landfill leachate onto microand mesoporous activated carbon", water research, vol. 46, pp. 491499. https://link.springer.com/chapter/10.1007/978-94-007-4470-7_2 https://link.springer.com/chapter/10.1007/978-94-007-4470-7_2 https://link.springer.com/chapter/10.1007/978-94-007-4470-7_2 https://link.springer.com/chapter/10.1007/978-94-007-4470-7_2 https://link.springer.com/chapter/10.1007/978-94-007-4470-7_2 https://www.ncbi.nlm.nih.gov/pmc/articles/pmc2556938/ https://www.ncbi.nlm.nih.gov/pmc/articles/pmc2556938/ https://www.ncbi.nlm.nih.gov/pmc/articles/pmc2556938/ https://www.ncbi.nlm.nih.gov/pmc/articles/pmc2556938/ https://www.tandfonline.com/doi/abs/10.1080/10408440500534032 https://www.tandfonline.com/doi/abs/10.1080/10408440500534032 https://www.tandfonline.com/doi/abs/10.1080/10408440500534032 https://www.tandfonline.com/doi/abs/10.1080/10408440500534032 https://link.springer.com/article/10.1007/bf02784599 https://link.springer.com/article/10.1007/bf02784599 https://link.springer.com/article/10.1007/bf02784599 https://pubs.acs.org/doi/abs/10.1021/es00064a001?journalcode=esthag https://pubs.acs.org/doi/abs/10.1021/es00064a001?journalcode=esthag https://pubs.acs.org/doi/abs/10.1021/es00064a001?journalcode=esthag https://pubs.acs.org/doi/abs/10.1021/es00064a001?journalcode=esthag https://journal.gnest.org/sites/default/files/journal%20papers/voudrias.pdf https://journal.gnest.org/sites/default/files/journal%20papers/voudrias.pdf https://journal.gnest.org/sites/default/files/journal%20papers/voudrias.pdf https://journal.gnest.org/sites/default/files/journal%20papers/voudrias.pdf https://journal.gnest.org/sites/default/files/journal%20papers/voudrias.pdf https://link.springer.com/chapter/10.1007/978-94-017-1278-1_8 https://link.springer.com/chapter/10.1007/978-94-017-1278-1_8 https://link.springer.com/chapter/10.1007/978-94-017-1278-1_8 https://link.springer.com/chapter/10.1007/978-94-017-1278-1_8 https://link.springer.com/chapter/10.1007/978-94-017-1278-1_8 https://www.sciencedirect.com/science/article/pii/s0011916409006067 https://www.sciencedirect.com/science/article/pii/s0011916409006067 https://www.sciencedirect.com/science/article/pii/s0011916409006067 https://www.sciencedirect.com/science/article/pii/s0011916409006067 https://www.sciencedirect.com/science/article/pii/s0301479710002483 https://www.sciencedirect.com/science/article/pii/s0301479710002483 https://www.sciencedirect.com/science/article/pii/s0301479710002483 https://www.sciencedirect.com/science/article/pii/s0301479710002483 https://www.sciencedirect.com/science/article/pii/s0301479710002483 https://link.springer.com/article/10.1007/s10311-005-0106-y https://link.springer.com/article/10.1007/s10311-005-0106-y https://link.springer.com/article/10.1007/s10311-005-0106-y https://link.springer.com/article/10.1007/s10311-005-0106-y https://www.sciencedirect.com/science/article/pii/s0045653500001764 https://www.sciencedirect.com/science/article/pii/s0045653500001764 https://www.sciencedirect.com/science/article/pii/s0045653500001764 https://www.sciencedirect.com/science/article/pii/s0045653500001764 https://www.sciencedirect.com/science/article/pii/s0045653504010100 https://www.sciencedirect.com/science/article/pii/s0045653504010100 https://www.sciencedirect.com/science/article/pii/s0045653504010100 https://www.sciencedirect.com/science/article/pii/s0304389408004810 https://www.sciencedirect.com/science/article/pii/s0304389408004810 https://www.sciencedirect.com/science/article/pii/s0304389408004810 https://www.sciencedirect.com/science/article/pii/s0304389408004810 https://www.sciencedirect.com/science/article/pii/s0304389408004810 https://www.sciencedirect.com/science/article/pii/s0304389408004810 https://pubs.acs.org/doi/abs/10.1021/acs.est.6b01897 https://pubs.acs.org/doi/abs/10.1021/acs.est.6b01897 https://pubs.acs.org/doi/abs/10.1021/acs.est.6b01897 https://pubs.acs.org/doi/abs/10.1021/acs.est.6b01897 https://pubs.acs.org/doi/abs/10.1021/acs.est.6b01897 https://pubs.acs.org/doi/abs/10.1021/acs.est.6b01897 https://www.sciencedirect.com/science/article/abs/pii/s0043135411006798 https://www.sciencedirect.com/science/article/abs/pii/s0043135411006798 https://www.sciencedirect.com/science/article/abs/pii/s0043135411006798 https://www.sciencedirect.com/science/article/abs/pii/s0043135411006798 https://www.sciencedirect.com/science/article/abs/pii/s0043135411006798 h. m. rashid and a. a.h. faisal / iraqi journal of chemical and petroleum engineering91,4 (2018) 39-45 04 [20] p. menoud, l. cavin, a. renken, 1998, "modelling of heavy metals adsorption to a chelating resin in a fluidized bed reactor", chemical engineering and processing, vol. 73, pp.89-101 ايونات الكادميوم من مياه الفضالت المموثة باستخدام مخمفات برادتي الحديد ازالة وااللمنيوم الصفر التكافؤ كمموثات مازة متوفرة محميا ورخيصة الخالصة تقوم الدراسة الحالية عمى فحص مدى قابمية وفعالية استخدام مخمفات برادة الحديد وااللمنيوم كفضالت متوفرة لقد تم استخدام ة وهو الكادميوم الذائب في الماء.اقتناص, اعاقة, وازالة اكثر العناصر الثقيمة خطور ورخيصة في -2( غم برادة المنيوم و)1-0.25( دقيقة ،جرعة )250-0معالم تجريبية في اختبارات الوجبة مثل زمن تماس ) -50)(،تركيز بدلئي لممموث 6-3مل من المحمول المائي المموث، دالة حامضية )100 \( غم برادة حديد8 200) mg/l ( دورة في الدقيقة حيث تحققت 250-0وسرعة تقّمب )ازالة لمكادميوم مقترنة بأفضل معالم %90 مل من 100 \( غم برادة حديد6غم برادة المنيوم و) 1)( دقيقة ،جرعة )250تجريبية وهي زمن التماس ) دورة 250 )وسرعة تقّمب ) mg/l 50)(، تركيز مموث بدائي ) 5.5المحمول المائي المموث، دالة حامضية ) ( هو افضل تمثيل لبيانات امتزاز الكادميوم iفي الدقيقة ومن خالل نتائج تجارب الوجبة تبّين ان موديل النكمير) وقد وجد ان بيانات حركيات التفاعل المتزاز 0.9115عمى برادة األلمنيوم والحديد وبمعامل ارتباط اكبرمن الكادميوم عمى خميط البرادتين وكنتيجة لمدى التقارب الحاصل بين النتائج النظرية والعممية تخضع لنموذج تفاعل الرتبة الثانية الكاذب حيث تكون الية االمتزاز الكيميائي هي المهيمنة عمى عممية االمتزاز. وبعد التفاعل بينها ةبين الكادميوم وقد لقد تم اجراء الفحص المجهري لكل من برادة الحديد وااللمنيوم قبل لوحظ بان هنالك تغييرات سطحيه لممواد المازة نتيجة لتشبعها بالمموث وغمق قنواتها المسامية والتي كانت سبب في توقف عممية االمتزاز. https://www.sciencedirect.com/science/article/abs/pii/s0255270197000421 https://www.sciencedirect.com/science/article/abs/pii/s0255270197000421 https://www.sciencedirect.com/science/article/abs/pii/s0255270197000421 https://www.sciencedirect.com/science/article/abs/pii/s0255270197000421 available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.20 no.1 (march 2019) 49 – 52 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: khalid hazem hassan, email: eng.khalid.1994@gmail.com , hassan a. h. abdul hussien, email: hahah692000@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. estimation of rock strength from sonic log for buzurgan oil field: a comparison study khalid hazem hassan and hassan a. h. abdul hussien university of baghdad-college of eng/ dept.of petroleum eng. abstract it is very difficult to obtain the value of a rock strength along the wellbore. the value of rock strength utilizing to perform different analysis, for example, preventing failure of the wellbore, deciding a completion design and, control the production of sand. in this study, utilizing sonic log data from (bu-50) and (bu-47) wells at buzurgan oil field. five formations have been studied (mishrif, sadia, middle lower kirkuk, upper kirkuk, and jaddala) firstly, calculated unconfined compressive strength (ucs) for each formation, using a sonic log method. then, the derived confined compressive rock strengthens from (ucs) by entering the effect of bore and hydrostatic pressure for each formation. evaluations the result of compared rock strength generated from two wells for the same formation and match the bottom and top of this formation in two wells. based on the obtained results, a good agreement between values of unconfined compressive strength from well (50) and well (47) that used real along of drilling section. the net results of the match between rock strength for wells (bu-50, bu47) of five formations; mishrif, sadia, middle lower kirkuk, upper kirkuk, and jaddala were 97, 87, 96.5, 97, 86 %, respectively keywords: drilling, unconfined rock strength, sonic log received on 18/11/8102, accepted on 16/01/8109, published on 30/03/8109 https://doi.org/10.31699/ijcpe.2019.1.7 1introduction the value of rock strength for each foot of the well, from the surface to the bottom of the hole, is very difficult to be achieved. for example, it is difficult to get the safe density for drilling fluid during the drilling of the different formations to avoid instabilities of the wellbore and when design the program of casing ‎[1]. it is very essential for a drilling engineer to know all the data associated with the strength of rock along the well because the production of sand during extraction of oil is also great degree depending on lithology of reservoir or strength of the rock. also, the penetration rate and wear of bit largely depend on the value of rock strength, where an increase in strength of rock led to increased wear of drilling bits and decreased penetration rate which increases the cost of drilling ‎[2]. several methods are used to calculate the strength of rock for each foot during the drilling process. first, we can calculate the strength of rock directly in the lab via a mechanical method on cutting or cores. in addition, the strength of rock can be calculated from log data which achieved during the drilling process by using sonic log along the well ‎[3]. finally, it can be calculated from the model of drilling, where utilizing data of drilling such as weight on bit, rotary speed and other drilling parameters for finding the mechanical properties of the rock. these drilling parameters can be obtained through the drilling process of the well for each foot ‎[4]. the main objective of this study is to calculate the value of the strength of the rock from the sonic log model where this value is called the unconfined compressive strength. after that, the study used value of unconfined compressive strength to calculate confined compressive strength for each well by depends on pore and hydrostatic pressure ‎[5]. 2calculation unconfined compressive strength the use of sonic velocity log to calculate rock elastic properties are well established. many correlations were presented between sonic travel time and rock strength or a grouping of different logs ‎[6], ‎[7]. rock strength depends mainly on lithology. the rock strength was high for the rocks with low porosity or low traveling time. the equation used in this study is show below ‎[4]. ( ( ) ) (1) where: δtc : time of traveling. s0s : rcock strength in case (ucs) k1, k2 are constants k1 = 5.15*10-8 k2 = 23.87 https://doi.org/10.31699/ijcpe.2019.1.7 k. h. hassan and h. a. h. abdul hussien / iraqi journal of chemical and petroleum engineering 20,1 (2019) 49 – 52 05 3calculating confined compressive strength of rock unconfined compressive rock strength (ucs) that calculated from sonic log do not use in the apply model so should calculate the confined compressive rock strength (ccs) from (ucs) for any well or formations in the same field when we want to use the rate of penetration model. confined compressive strength (ccs) calculation depends on hydrostatic and pore pressure because the drilling model use confined rock strength and the value of rock strength, which got from sonic model do not contain on the effect of the difference between hydrostatic pressure and pore. rock strength is the chief element of the drilling models ‎[8]. ( ) (2) s: (ccs) in mpa, so: (ucs) in mpa, pe different between pore and hydrostatic pressure. (as,bs) are fitting constants showing in table 1. table 1. chip hold-down permeability coefficients ‎[9] formation permeable impermeable pe ph-pp ph ac 0.00497 0.0141 bc 0.757 0.470 cc 0.103 0.569 as 0.0133 0.00432 bs 0.577 0.782 4results the results of this work are presented for two wells (bu-47); (bu-50) wells. the results are listed in the following figures (1 to 5) studies formation. these formations include mishrif, sadia, middle lower kirkuk, upper kirkuk, and jaddalla formations. fig. 1. comparison the values of ucs and ccs between (bu-50) and (bu-47) wells for mishrif formation fig. 2. comparison the values of ucs and ccs between (bu-50) and (bu-47) wells for sadia formation fig. 3. comparison the values of ucs and ccs between (bu-50) and (bu-47) wells for middle lower kirkuk formation fig. 4. comparison the values of ucs and ccs between (bu-50) and (bu-47) wells for upper kirkuk formation k. h. hassan and h. a. h. abdul hussien / iraqi journal of chemical and petroleum engineering 20,1 (2019) 49 – 52 05 fig. 5. comparison the values of ucs and ccs between (bu-50) and (bu-47) wells for jaddala formation 5discussion figures (1 to 5) represent the comparison between (bu-50), (bu-47) for the unconfined compressive rock strength that is calculated from the measuring sonic log with confined compressive rock strength which calculated from ucs with depth. the difference between confined rock strength and unconfined rock strength depend on the value of hydrostatic and pore pressure. when the value of the difference between pore and hydrostatic pressure is very high that led to increasing differences between unconfined and confined compressive strength for each formation. it can be noticed that there is an only slight difference between the values of unconfined and confined compressive rock strength in upper kirkuk formation. mishrif, sadia middle lower kirkuk has a high difference between unconfined confined compressive rock strength because there is a high difference between the hydrostatic and the pore pressure. the values of rock strength changed with depth, because of varying in the lithology with depth. in addition, it can be noticed the value of rock strength increases with depth. this increase in depth led to rising the rock strength. the rock strength in mishrif formation was higher than all formations because it is the deeper formation. the value of match for unconfined compressive strength between (bu-50) and (bu-47) for five formations (mishrif, sadia, middle lower kirkuk, upper kirkuk and jaddala) was (97%, 87%, 96.5%, 97%, 86%) respectively. 6conclusions the values of unconfined compressive rock strength that obtain from (bu-50) well using sonic log tool have a very good match with the value of unconfined compressive rock strength which determined from (bu47) well for all formations. in addition, the difference between the values of confined and unconfined depends on the value of hydrostatic pressure for the same formation in two wells. the value of unconfined compressive rock strength mainly rose with increasing depth. nomenclatures symbol definition ac chip hold-down coefficient, dimensionless ad drag-bit lithology coefficient, dimensionless as rock-strength lithology coefficient, dimensionless be chip hold-down coefficient, dimensionless bd drag-bit lithology coefficient, dimensionless bs rock-strength lithology coefficient, dimensionless cc chip hold-down coefficient, dimensionless pe effective differential or confining pressure, psi ph mud column hydrostatic pressure, psi pp pore pressure, psi s confined rock strength, psi so unconfined rock strength, psi references [1] e. e. okpo, a. dosunmu, b. s. odagme, and p. harcourt, “artificial neural network model for predicting wellbore instability,” no. august, pp. 2–4, 2016. [2] a. asadi, “application of artificial neural networks in prediction of uniaxial compressive strength of rocks using well logs and drilling data,” procedia eng., vol. 191, pp. 279–286, 2017. [3] r. between, f. strength, d. strength, and e. l. properties, “spe 18166 relationships between formation strength, drilling strength, and electric log properties,” 1988. [4] p. b. kerkar, s. i. e, g. hareland, and e. r. fonseca, “iptc 17447 estimation of rock compressive strength using downhole weight-on-bit and drilling models,” 2014. [5] hareland, geir, and runar nygaard, “calculating unconfined rock strength from drilling data, ” 1st canadaus rock mechanics symposium. american rock mechanics association, 2007. [6] tokle, k., p. horsrud, and r. k. bratli, “predicting uniaxial compressive strength from log parameters, ” spe annual technical conference and exhibition. society of petroleum engineers, 1986. [7] kazi, asadullah, zekai sen, and bahaa-eldin h. sadagah, “relationship between sonic pulse velocity and uniaxial compressive strength of rocks, ” the 24th us symposium on rock mechanics (usrms). american rock mechanics association, 1983. [8] m. rastegar, g. hareland, r. nygaard, and a. bashari, “optimization of multiple bit runs based on rop models and cost equation: a new methodology applied for one of the persian gulf carbonate fields,” proc. iadc/spe asia pacific drill. technol. conf. exhib., 2008. [9] p. r. rampersad, g. hareland, and p. boonyapaluk, “drilling optimization using drilling data and available technology,” pp. 317–325, 1994. https://www.onepetro.org/conference-paper/spe-184371-ms https://www.onepetro.org/conference-paper/spe-184371-ms https://www.onepetro.org/conference-paper/spe-184371-ms https://www.sciencedirect.com/science/article/pii/s1877705817323226 https://www.sciencedirect.com/science/article/pii/s1877705817323226 https://www.sciencedirect.com/science/article/pii/s1877705817323226 https://www.sciencedirect.com/science/article/pii/s1877705817323226 https://www.onepetro.org/conference-paper/spe-18166-ms https://www.onepetro.org/conference-paper/spe-18166-ms https://www.onepetro.org/conference-paper/spe-18166-ms http://www.earthdoc.org/publication/publicationdetails/?publication=74694 http://www.earthdoc.org/publication/publicationdetails/?publication=74694 http://www.earthdoc.org/publication/publicationdetails/?publication=74694 https://www.onepetro.org/conference-paper/arma-07-214 https://www.onepetro.org/conference-paper/arma-07-214 https://www.onepetro.org/conference-paper/arma-07-214 https://www.onepetro.org/conference-paper/arma-07-214 https://www.onepetro.org/conference-paper/spe-15645-ms https://www.onepetro.org/conference-paper/spe-15645-ms https://www.onepetro.org/conference-paper/spe-15645-ms https://www.onepetro.org/conference-paper/spe-15645-ms https://www.onepetro.org/conference-paper/arma-83-0409 https://www.onepetro.org/conference-paper/arma-83-0409 https://www.onepetro.org/conference-paper/arma-83-0409 https://www.onepetro.org/conference-paper/arma-83-0409 https://www.onepetro.org/conference-paper/arma-83-0409 https://www.onepetro.org/conference-paper/spe-114665-ms https://www.onepetro.org/conference-paper/spe-114665-ms https://www.onepetro.org/conference-paper/spe-114665-ms https://www.onepetro.org/conference-paper/spe-114665-ms https://www.onepetro.org/conference-paper/spe-114665-ms https://www.onepetro.org/conference-paper/spe-27034-ms https://www.onepetro.org/conference-paper/spe-27034-ms https://www.onepetro.org/conference-paper/spe-27034-ms k. h. hassan and h. a. h. abdul hussien / iraqi journal of chemical and petroleum engineering 20,1 (2019) 49 – 52 05 تقدير مقاومة الصخرة من التسجيل الصوتي لحقل البزركان النفطي :دراسة مقارنة الخالصة تستخدم من الصعب جدًا الحصول عمى قيمة قوة الصخور عمى طول حفرة البئر. قيمة قوة الصخور التي إلجراء أنواع مختمفة من التحميل عمى سبيل المثال منع فشل جدار البئر ، وتحديد تصميم االكمال ، والتحكم في إنتاج الرمال. في هذه الدراسة يتم استخدام بيانات التسجيل الصوتي لحقل البزركان النفطي ، وطبقت هذه ، حساب قيمة قوة الضخرة بدون تاثير ضغط عمود ( . أوالbu-47)( )bu-50التالية الدراسة عمى االبار ( لكل تكوين من التسجيالت الصوتية اثناء الحفر . ان ucsالطين و ضغط التكوينات والتي يطمق عميها ب ) نتائج قوة الصخرة التي يتم الحصول عميها بتطبيق نموذج التسجل الصوتي ال تحتوي عمى تاثير ضغط عمود كوين وال يمكن استخدامها في تطبيق معادالت نماذج االختراق لذلك يتم حساب قوة ل وكذلك ضغط التئالسا باالعتماد عمى ضغط التكوين وضغط عمود السائل اثناء الحفر . ولمتاكد ucs)من قيمة ) (ccs)الصخرة ة بين قوة الصخرة لبئرين ومعرفة مدى التطابق بينهما .نمن نتائج قوة الصخرة تم المقار بناءا عمى النتائج التي تم الحصول عميها ، هناك تطابق جيد بين قيم قوة الصخرة التي تم حسابها من باالعتماد عمى التسجيالت الصوتية. حيث ان قيمة تطابق النتائج بين قوة (bu_50), (bu-47)االبار mishrif, sadia, middle lower kirkuk, upper kirkuk, jaddalالصخور لخمس تكوينات والتي هي عمى التوالي )٪.7٪، 58٪، 9..5٪ ، 78٪ ، 97 (كانت ijcpe vol.10 no.3 (september 2009) iraqi journal of chemical and petroleum engineering vol.10 no.3 (september 2009) 41-49 issn: 1997-4884 reducing the evaporation of stored iraqi crude oil g. a. r. rassoul * and tahseen hameed khlaif * chemical engineering department college of engineering university of baghdad – iraq abstract in order to reduce the losses due to evaporation in the stored crude oil and minimizing the decrease in °api many affecting parameters were studied (i.e. different storage system, namely batch system with d ifferent types of storage tanks under different temperatures and:or different pressures). continuous circulation storage system was also studied. it was found that increasing pressure of the inert gas from 1 bar to 8 bar over the surface of the crude oil will decrease the percentage losses due to evaporation by (0.016%) and decrease the change of °api by (0.9) during 96 hours storage time. similarly using covering by surfactant (potassium oleate) or using polymer (polyurethane foam) decreases the percentage evaporation losses compared with uncovered surface of the blend crude oil. in each surfactants and polymers the layer thickness was (1.0, 1.5, 2.0, 2.5, 3.0 cm), and increasing the thickness of the surfactant to 2.5 cm or of the polymer to 3 cm was found to be best required thickness. surfactant gave lower percentage evaporation losses than polymer, for fixed roof tank (i.e. 0.299%, 0.383%) for 120 hours evaporation time. different processed storage tanks namely (fixed roof, external moving roof, fixed and internal moving) were studied and fixed and moving roof was the best in reducing evaporation losses (0.453%) for 120 hours. in continuous circulation for proposed continuous storage system, the percentage evaporation losses for covered with surfactant, covered with polymer, and uncovered surface of blend crude oil were (0.328%), (0.378%), and (0.45%) respectively at 24 °c for 96 hours evaporation time. introduction during storage the losses due to evaporation occurred which means high cost losses especially when the oil prices are high, and also causes pollution. different types of the storage tanks to minimize hydrocarbons evaporation losses were designed [1, 2], since for example there are half million storage tanks in usa. other techniques cooling of the surface of the storage tanks by showering water over them with water. this process is still be used now. painting the external metallic of the storage tank with white paint in order to reflect the heat coming from the sun light. heat insulation materials are used to minimize the percentage evaporation losses. there are different types of losses such as filling losses (working losses), running losses, breathing losses [3, 4]. different internal design of storage tanks were considered, similarly different types of polymers were used to minimize evaporation losses. also different surfactants were used to reduce evaporation. continuous circulation of the crude oil will increase evaporation losses. in order to capture the volatile escaped, vapour were collected from special vents, cooling the condensed liquid again before recycling to the storage tanks. experimental work aim of the work 1decreasing iraq crude oil evaporation in the storage tank. 2studying the effectiveness of different types of surfactant and polymers to prevent crude oil evaporation. 3studying the effect of different storage conditions (i.e. temperature, pressure, space volume, and storage type). 4studying the effects of storage type and recycling crude. university of baghdad college of engineering iraqi journal of chemical and petroleum engineering reducing the evaporation of stored iraqi crude oil 42 ijcpe vol.10 no.3 (september 2009) materials used 1iraqi blends crude oil from dura refinery. 2polyurethane foam. 3potassium oleate (c17h33cook). apparatus the apparatus composed of: 1cylindrical iron fixed roof storage tank (13.5 cm inside diameter, 14cm outside diameter and 39.5 cm high) which contains cone cover of five hatches in the top of the tank for gas inlet, digital thermometer, pressure gauge , one inlet to the tank and one outlet from the tank. 2cylindrical iron external moving roof storage tank (13.5 cm inside diameter, 14cm outside diameter and 39.5 cm high) which contains flat external moving roof with its controller. 3cylindrical iron fixed and internal moving roof storage tank (13.5 cm inside diameter, 14cm outside diameter and 39.5 cm high) which contains two roofs. one roof is cone cover of five hatches in the top of the tank for gas inlet, digital thermometer and pressure gauge and the other roof is flat internal moving roof with its controller. 4cylindrical iron storage tanks with different inside diameters (i.e. 12.5 cm, 10 cm, 8.5 cm) which contains flat cover with three hatches in the top of the tank for digital thermometer, pressure gauge, and vent. 5water bath. 6tank (qvf). 7pumps. surfactant testing the surfactants which were used must not react with crude oil and float on its surface. therefore, many types of surfactants were tested (which are listed in the used material). 500 ml of blend crude oil was put in each beaker (800ml) and covered with a layer of surfactant and left there for 24 hours. one type of surfactant (potassium oleate) succeeded experimentally. similarly one type of polymer (polyurethane foam) also succeeds experimentally. layer thickness evaporation losses were studied using different polymer thickness and different surfactant thickness (1, 1.5, 2.0, 2.5, and 3.0) cm. the time in each experiment was 24 hours. differences in weights of crude oil between before and after the experiment indicate the percentage evaporation losses. evaporation time three litters of blend crude oil were put in cylindrical tank with diameter (13.5 cm). sensitive balance was used to weigh the crude oil at time zero. then, weighing the crude oil was carried after leaving it for different accumulative times (24, 48, 72, 96, 120) hours. the differences in weight at time zero and the weight at other accumulative times represent the percentage evaporation losses. the crude oil was covered with either potassium oleate surfactant (2.5 cm) thickness or polyurethane foam (3.0 cm) thickness. the differences in weights before and after different accumulative times were evaluated. after each run the (api) gravity was measured using picknometer device (astm ip 120/64). three types of tanks were studied. similar experimental procedure were used for external moving roof tank and fixed and internal moving roof tank as those described above for fixed roof tank. in external moving roof tank the top roof is moving up and down so that it can cover and close the opening of the tank. fixed and internal moving roof tank contains two roofs. one movable roof covers the surface of the crude oil and the second roof covers the opening of the tank. temperatures of crude oil three litters of blend crude oil were put in cylindrical tank at constant temperature using water path for 24 hours, and covered with either potassium oleate surfactant (2.5cm) thickness or polyurethane foam polymer (3.0cm) thickness or uncovered at different temperatures. digital thermometer was used to measure crude oil temperature (i.e. 16, 40, 50, 60, 70) °c. percentage evaporation losses were measured in each case. space height above crude oil different space height (11.5, 18.5, 25, 32)cm, that is different space volumes (1644.5, 2645.5, 3575, 4576) cm 3 were used for studying evaporation losses in tank with and without polyurethane foam or with or without potassium oleate after 24 hours in each experimental tests. evaporation losses were calculated from the difference of weights of crude oil before and after each experimental test. surface area effect storage tanks of different diameters (8.5, 10.5, 12.5 and 13.5) cm, that is different surface areas (56.7, 78.5, 122.6, 143) cm 2 and different quantity of crude oil covered with either potassium oleate surfactant (2.5cm) thickness or polyurethane foam (3.0cm) thickness or uncovered and at constant space volumes were studied for 24 hours. g. a. r. rassoul and tahseen hameed khlaif 43 ijcpe vol.10 no.3 (september 2009) tank pressure storage tank with three liters of blend crude oil covered with either potassium oleate surfactant or polyurethane foam polymer or uncovered were subjected to different pressure (1, 2, 4, 6, 8 bar) by using nitrogen gas as inert gas. evaporation losses were evaluated from the differences of crude oil weights between before and after the experiment. recycling time a continuous recycling unit consists of two storage tanks fixed roof tank and qvf glass tank. fixed roof tank was connected by plastic pipes to qvf glass tank controlled by manual control valve using two pumps which were controlled by electrical timer board. this continuous circulation process was carried out at different periods of times i.e. (24, 48, 72, 96) hours. five litters of crude oil was put in the main fixed roof storage tank and then it was pumped to the second storage tank (discharging process). then the crude oil returned back to the main storage tank by gravity (filling process). this circulation process was controlled by valves. the output stream from the main storage tank was closed for 30 seconds to allow the crude oil to return to the fixed roof storage tank (filling process). then the electrical power of the pumps was switched off. the inlet stream of the main storage tank was closed. percentage evaporation losses were evaluated for crude oil covered with either potassium oleate surfactant (2.5cm) thickness or polyurethane foam (3.0cm) thickness or uncovered surface. results and discussion effect of layer thickness of surfactant and layer thickness of polymer: potassium oleate surfactant and polyurethane foam were used because they float over oil surface. thus only two materials float over the crude oil out of ten materials studied and hence decreasing evaporation losses. percentage of evaporation losses versus layer thickness of polymer and layer thickness of surfactant are shown in figs.1 and 2 respectively. the evaporation losses from crude oil using potassium oleate is less than using polyurethane foam. the minimum thickness required to reduce evaporation losses, almost completely was found to be (2.5cm) for potassium oleate, and (3cm) for polyurethane foam. the surfactant layers covered the crude oil surface which separates oil surface from atmospheric air and isolates it. therefore, it reduced the evaporation losses from crude surface due to the space above. potassium oleate isolation is more than polyurethane foam due to the differences in permeability and surface tension of the polymer and surfactant used [5,6]. layer thickness (cm) % e v a p o ra ti o n l o s s e s 0.00 0.02 0.04 0.06 0.08 0.10 0.8 1.2 1.6 2.0 2.4 2.8 3.2 evaporation time= 24hr d=13.5 cm volume space= 2645.5 cm 3 temp= 16 c 0 surface area=143 cm 2 fig. 1 percentage evaporation losses vs. layer thickness with polyurethane cover. layer thickness % e v a p o ra ti o n l o s s e s 0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.8 1.2 1.6 2.0 2.4 2.8 3.2 evaporation time= 24hr d=13.5 cm volume space= 2645.5 cm 3 temp= 16 c 0 surface area=143 cm 2 fig. 2 percentage evaporation losses vs. layer thickness with potassium oleate cover effect of time figs. 3 and 4 show the relation between the percentage evaporation losses of crude oil with time when the surface of crude oil covered with either surfactant or polymer and with neither surfactant nor polymer. percentage crude oil evaporation losses increases with time due to the evaporation processes proceeding with time. light components were mainly evaporated during the first (24 hours) from crude oil as indicated by api measurement. later for the next 24 hours, the evaporation rate decreases with time because the more volatile components evaporate at first. the heavier components take longer time to evaporate, as indicated after 120 hours evaporation. the percentage evaporation losses decrease from 0.50% to 0.35% after 120 hours when the blend crude oil was covered with polymer as shown in fig.3, in which, the percentage evaporation losses decrease from 0.50% to 0.27% after 120 hours when the blend crude oil was covered with surfactant as shown in fig.4. reducing the evaporation of stored iraqi crude oil 44 ijcpe vol.10 no.3 (september 2009) time (hr) % e v a p o ra ti o n l o s s e s 0.05 0.15 0.25 0.35 0.45 0.55 10 30 50 70 90 110 130 with out cover with polyurethan cover temp=16 c 0 d=13.5 cm volume space= 2645.5 cm 3 layer thick of polyurethan = 3 cm surface area=143 cm 2 fig. 3 percentage evaporation losses vs. time. time (hr) % e v a p o ra ti o n l o s s e s 0.0 0.1 0.2 0.3 0.4 0.5 0.6 10 30 50 70 90 110 130 w ithout cover w ith potassium oleate cover temp=16 c 0 d=13.5 cm volume space= 2645.5 cm 3 layer thick of surf actent = 2.5 cm surf ace area=143 cm 2 fig. 4 percentage evaporation losses vs. time. effect of temperature figs. 5 and 6 represent the relationship between the percentage evaporation losses of crude oil with storage tank temperature. when the temperature increases, the percentage evaporation losses increases, because the temperature of crude oil increased, hence the energy of molecules increases and this leads to increase molecules motion and this may make light component librated (43,44) . the percentage evaporation losses decrease from 0.13% to 0.07% at 20 °c and from 0.27% to 0.18% at 70 °c when the blend crude oil was covered with polyurethane foam. similar the percentage evaporation losses decrease from 0.13% to 0.05% at 20 °c and from 0.27% to 0.14% at 70 °c when the blend crude oil was covered with potassium oleate. the difference between the behavior of the surfactant and polymer due to the difference in permeability and surface tension [6,8]. temperature (c 0 ) % e v a p o ra ti o n l o s s e s 0.02 0.06 0.10 0.14 0.18 0.22 0.26 0.30 10 20 30 40 50 60 70 80 with out cover with polyurethan cover evaporation time= 24hr d=13.5 cm volume space= 2645.5 cm 3 layer thick of polymer = 3 cm surface area=143 cm 2 fig. 5 percentage evaporation losses vs. temperature. temperature (c 0 ) % e v a p o ra ti o n l o s s e s 0.02 0.06 0.10 0.14 0.18 0.22 0.26 0.30 10 20 30 40 50 60 70 80 with out cover with potassium oleate cover evaporation time= 24hr d=13.5 cm volume space= 2645.5 cm 3 layer thick of surfactent = 2.5 cm surface area=143 cm 2 fig. 6 percentage evaporation losses vs. temperature. 4. effect of exposed surface area: figs. 7, 8 shows the relation between percentage evaporation losses of the crude oil with the exposed surface area of the blend crude oil at constant other conditions. figs. 9, 10 shows the relation between percentage evaporation losses of the crude oil per unit area (cm 2 ) with the exposed surface area of the blend crude oil at constant other conditions. when the blend crude oil area increases the percentage of the crude oil evaporation losses increases. the contact between the above space and surface of crude oil increases leads to evaporating the more volatile components. the percentage evaporation losses increase from 0.089% to 0.11% when exposed surface area increases from 78.5 cm 2 to 143 cm 2 for polymer. the percentage evaporation losses increase from 0.055% to 0.073% when exposed surface area increases from 78.5 cm 2 to 143 cm2 for surfactant. the percentage evaporation losses per unit exposed surface area (cm 2 ) decreases from 0.113*10 -2 % to 0.077*10 -2 % for polymer when exposed surface area increases from 78.5 cm 2 to 143 cm 2 respectively. while the percentage evaporation losses per unit exposed fig. 8 percentage evaporation losses vs. exposed surface area. g. a. r. rassoul and tahseen hameed khlaif 45 ijcpe vol.10 no.3 (september 2009) surface area (cm 2 ) decreases from 0.07*10 -2 % to 0.051*10 -2 % for surfactant when exposed surface area increases from 78.5 cm 2 to 143 cm 2 respectively. this indicated that other parameters such as height of blend crude oil under the surfactant play some role in changing the percentage evaporation losses [6]. surface area (cm 2 ) % e v a p o ra ti o n l o s s e s s 0.07 0.08 0.09 0.10 0.11 0.12 0.13 0.14 0.15 0.16 50 70 90 110 130 150 with out cover with poly urethan cover evaporation tim e= 24hr tem p= 16 c 0 layer thick of polym er = 3 cm space volum e = 2645.5 cm 3 fig. 7 percentage evaporation losses vs. exposed surface area. surface area (cm 2 ) % e v a p o ra ti o n l o s s e s 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 50 70 90 110 130 150 with out cover with potas s ium oleate cover evaporation tim e= 24hr tem p= 16 c 0 layer thick of s urfactant = 2.5 cm space volum e = 2645.5 cm 3 fig. 8 percentage evaporation losses vs. exposed surface area. surface area (cm 2 ) % e v a p o ra ti o n l o s s e s p e r u n it a re a ( c m2 )* 1 0 -2 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20 0.22 50 70 90 110 130 150 with out cover with poly urethan cover evaporation tim e= 24hr tem p= 16 c 0 layer thick of polym er = 3 cm space volum e = 2645.5 cm 3 fig. 9 percentage evaporation losses per unit area vs. exposed surface area. surface area (cm 2 ) % e v a p o ra ti o n l o s s e s p e r u n it a re a ( c m 2 )* 1 0 -2 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20 0.22 50 70 90 110 130 150 w ith out cover w ith potassium oleate cover evaporation time= 24hr temp= 16 c 0 layer thick of surfactant = 2.5 cm space volume = 2645.5 cm 3 fig. 10 percentage evaporation losses per unit area vs. exposed surface area. effect of pressure figs. 11, 12 illustrate the relation between percentage evaporation losses of the crude oil with pressure in the storage tank using different values of pressure (i.e. between 1to 8 bar). when pressure increases the evaporation losses of the crude oil decreases because of the equilibrium between the liquid crude oil and its vapor which fastly decrease the evaporation losses from crude oil. as indicated by simple perfect equilibrium equation which states (pp = x p * γ = y pt ф). as pressure increases evaporation decreases, since it reduces molecules movements near the surface of the crude oil since some of hydrocarbons up to c3, c4 liquefies at (8 bar) at room temperature (i.e. 25 °c). the percentage evaporation losses decreases from 0.15% to 0.11% and 0.017% when exposed to pressure from 1 bar, 2 bar and to 8 bar respectively when the blend crude oil was uncovered. the percentage evaporation losses decreases from 0.09% to 0.01% when exposed to pressure from 2 bar to 8 bar respectively when the blend crude oil was covered with polymer. the percentage evaporation losses decrease from 0.07% to 0% when exposed to pressure from 2 bar to 8 bar respectively when the blend crude oil was covered with surfactant. the pressure gauge a good control in reducing evaporation rate with or without using either polymer or surfactant as reduce evaporation rate to 0.02% from 0.15% at 8 bar. but the disadvantage with pressure which are high capital operational cost. reducing the evaporation of stored iraqi crude oil 46 ijcpe vol.10 no.3 (september 2009) pressure (bar) % e v a p o ra ti o n l o s s e s 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0 1 2 3 4 5 6 7 8 9 with out cover with poly urethan cover evaporation time= 24hr temp= 24 c 0 layer thick of polymer = 3 cm volume space = 2645.5 cm 3 fig. 11 percentage evaporation losses vs. pressure. pres s ure (bar) % e v a p o ra ti o n l o s s e s 0.00 0.04 0.08 0.12 0.16 0 1 2 3 4 5 6 7 8 9 with out cover with potas s ium oleate cover evaporation tim e= 24hr tem p= 24 c 0 layer thick of s urfactant = 2.5 cm volum e s pace = 2645.5 cm 3 fig. 12 percentage evaporation losses vs. pressure. space volume above surface of crude oil figs.13, 14 represent relation between percentage evaporation losses of the crude oil with the space volume above crude oil surface in the storage tank. when space volume above the crude oil surface in the tank increases the evaporation quantity of crude oil increases due to longer time required to reach the equilibrium between the liquid crude blend oil and its vapour in the space above the surface while when the space volume of storage tank decreases the space above the crude oil will be quickly saturated with its vapour. for closing tank without additions, the evaporation losses were 0.045% to 0.12% for 2000 cm 3 and 5000 cm 3 space volume above blend crude oil respectively at 24 °c. the results indicated decreases in percentage evaporation losses from 0.045% to 0.03% and to 0.02% for uncovered blend crude oil, polymer covered oil, and surfactant covered oil respectively when space volume was 2000 cm 3 . lower results of percentage evaporation losses were obtained from uncovered oil, polymer covered oil, and surfactant covered oil. these percentage evaporation losses were 0.12%, 0.11%, 0.08% respectively when space volume above blend crude oil was 5000 cm 3 . space volume (cm 3) % e v a p o ra ti o n l o s s e s 0.01 0.03 0.05 0.07 0.09 0.11 0.13 1400 2000 2600 3200 3800 4400 5000 w ith out cover w ith polyurethan cover evaporation time= 24hr temp= 24 c 0 layer thick of polymer = 3cm d= 13.5 cm surf ace area= 143 cm 2 fig. 13 percentage evaporation losses vs. space volume. space volume (cm 3) % e v a p o ra ti o n l o s s e s 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 1400 2000 2600 3200 3800 4400 5000 w ith out cover w ith potassium oleate cover evaporation time= 24hr temp= 24 c 0 layer thick of surf actant = 2.5 cm d= 13.5 cm surface area= 143 cm 2 fig. 14 percentage evaporation losses vs. space volume. effect of recycling figs. 15 and 16 represent the relation between the percentage evaporation losses of crude oil with recycling for different times namely 24, 48, 72, and 96 hours. this operation was carried out continuously for above time intervals for uncovered blend crude oil, covered blend oil with polyurethane foam and covered blend oil with potassium oleate. weighing was carried out for each sample for each interval. in each operation total oil volume was five liters. in the recycle continuous storage system, when the storage time increases the percentage evaporation losses of crude oil increases. fig.17, compares between the evaporation losses of crude oil in the batch storage tank and continuous storage tank for uncovered blend crude oil, which shows percentage of crude oil in the continuous storage tank more than in the batch storage tank for the same time. the difference in evaporation losses between both cases decreases with storage time, but still there is a difference. the energy of continuous flowing crude oil is more than the static due to forced motions of the crude which are similar to the behavior of filling and discharging. fig. 18 represents the difference of percentage evaporation losses in the batch g. a. r. rassoul and tahseen hameed khlaif 47 ijcpe vol.10 no.3 (september 2009) and in the continuous storage tank when the surface of crude oil covered with layer of polyurethane foam. fig.19 represents the difference of percentage evaporation losses in the batch and in the continuous storage tank when the surface of crude oil covered with layer of oleate soap. figs. 18, 19 show that there is higher rate of evaporation of blend crude oil with continuous recycle compared with batch with storage time for blend oil covered with polyurethane and potassium oleate respectively. the results indicated to an increase of 0.04% in percentage evaporation losses when crude oil covered with polymer compared with 0.05% in percentage evaporation losses when crude oil covered with surfactant. this indicated it is almost the same behavior of the two cases due to energy movements. recycling time (hr) % e v a p o ra ti o n l o s s e s 0.24 0.28 0.32 0.36 0.40 0.44 0.48 10 30 50 70 90 110 w ithout cover w ith poly urethan cover temp= 24 c 0 layer thick of polymer = 3 cm d= 13.5 cm surface area= 143 cm 2 fig. 15 percentage evaporation losses vs. recycling time. recycling time (hr) % e v a p o ra ti o n l o s s e 0.18 0.24 0.30 0.36 0.42 0.48 10 30 50 70 90 110 w ithout cover w ith potassium oleate cover temp= 24 c 0 layer thick of surf actant = 2.5 cm d= 13.5 cm surf ace area= 143 cm 2 fig. 16 percentage evaporation losses vs. recycling time. time (hr) % e v a p o ra ti o n l o s s e s 0.12 0.18 0.24 0.30 0.36 0.42 0.48 10 30 50 70 90 110 for batch process for continuous process temp=24 c 0 d=13.5 cm layer thick = without cover surface area=143 cm 2 fig. 17 compares between the evaporation losses of crude oil in the batch and continuous storage tank with out cover tim e (hr) % e v a p o ra ti o n l o s s e s 0.08 0.12 0.16 0.20 0.24 0.28 0.32 0.36 0.40 10 30 50 70 90 110 for batch proces s for continuous proces s tem p=24 c 0 d=13.5 cm layer thick of polym er = 3 cm s urface area=143 cm 2 fig. 18 compares between the evaporation losses of crude oil in the batch and continuous storage tank with polyurethane cover tim e (hr) % e v a p o ra ti o n l o s s e s 0.04 0.08 0.12 0.16 0.20 0.24 0.28 0.32 0.36 10 30 50 70 90 110 for batch proces s for continuous proces s tem p=24 c 0 d=13.5 cm layer thick of s urfactant = 2.5 cm s urface area=143 cm 2 fig. 19 compares between the evaporation losses of crude oil in the batch and continuous storage tank with potassium oleate cover reducing the evaporation of stored iraqi crude oil 48 ijcpe vol.10 no.3 (september 2009) effect of evaporation on° api figs. 20, 21 represent the relation between the °api of crude oil with time. when the time increases, °api of crude oil decreases because °api varies inversely with specific gravity, i.e. when light components evaporate with time, the specific gravity increases and °api decreases. the above figures shows an increase in °api of using surfactant rather than polyurethane foam. both surfactant and polymer gave high °api after 110 hrs compared with uncovered blend crude oil. the increase in °api was 0.7 which means an increase in the profit of selling crude oil. therefore two improvements costs were obtained, i.e. high °api of stored crude and less losses of the hydrocarbon vapor from the crude. figs. 22, 23, 24 represent the relation between evaporation losses with °api. when accumulative evaporation losses increases °api decreases due to the increase in the s.g of crude oil. initially the percentage evaporation losses was higher than later one. this gaves a higher decrease in °api per unit time than later one. the decrease in °api was reduced when crude oil was covered with polyurethane compared with uncovered crude oil as shown in figs. 22, 23. the later gave higher decrease in °api than when the crude oil was covered with potassium oleate as shown in fig. 24. time (hr) a p i g ra v it y 29.3 29.5 29.7 29.9 30.1 30.3 30.5 10 30 50 70 90 110 w ithout cover w ith poly urethan cover temp= 24 c 0 layer thick of polymer = 3 cm d= 13.5 cm volume space = 2645.5 cm 3 surf ace area= 143 cm 2 fig. 20 api gravity vs. time. time (hr) a p i g ra v it y 29.3 29.5 29.7 29.9 30.1 30.3 30.5 10 30 50 70 90 110 w ithout cover w ith potassium oleate cover temp= 24 c 0 layer thickof surf actant = 2.5 cm d= 13.5 cm volume space = 2645.5 cm 3 surf ace area= 143 cm 2 fig. 21 api gravity vs. time. api gravity % e v a p o ra ti o n l o s s e s 0.12 0.18 0.24 0.30 0.36 0.42 29.3 29.5 29.7 29.9 30.1 30.3 30.5 without cover temp= 24 c 0 layer thick= without cover d= 13.5 cm volume space = 2645.5 cm 3 surface area= 143 cm 2 fig. 22 percentage evaporation losses vs. api gravity with out cover. api gravity % e v a p o ra ti o n l o s s e s 0.08 0.12 0.16 0.20 0.24 0.28 0.32 0.36 29.85 29.95 30.05 30.15 30.25 30.35 without polyurethane cover temp= 24 c 0 layer thick of polymer = 3 cm d= 13.5 cm volume space = 2645.5 cm 3 surface area= 143 cm 2 fig. 23 percentage evaporation losses vs. api gravity with polyurethane cover. api gravity % e v a p o ra ti o n l o s s e s 0.04 0.08 0.12 0.16 0.20 0.24 0.28 29.96 30.04 30.12 30.20 30.28 30.36 with potas s ium oleate cover tem p= 24 c 0 layer thick of s urfactant = 2.5 cm d= 13.5 cm volum e s pace = 2645.5 cm 3 surface area= 143 cm 2 fig. 24 percentage evaporation losses vs. api gravity with potassium oleate cover. g. a. r. rassoul and tahseen hameed khlaif 49 ijcpe vol.10 no.3 (september 2009) conclusions the following conclusions can be obtained from this experimental research: 1some polymers and some surfactant failed to cover over the surface of the blend crude oil and therefore can not be used. 2the best thickness of polymer and surfactant, which were used to cover the surface of blend crude oil, was 2.5 cm or 3.0 cm respectively. 3the obtained results indicated that the surfactant (potassium oleate) is better in reducing evaporation losses rather than polyurethane polymer. 4in batch process, surfactant coverage gave percentage evaporation losses (i.e. 0.147%) less than uncovered blend crude oil (i.e. 0.275%) at 70 °c, surface area 143 cm 2 , dead space 2645.5 cm 3 , height of crude oil 21 cm , evaporation time 24 hours, for fixed roof tank. in batch process polymer coverage, gave percentage evaporation losses (0.194%) less than uncovered oil (0.275%) at 70 °c, and at the same above conditions. 5the measured original °api equals (30.3). the °api for crude oil covered with surfactant, covered with polymer, and uncovered blend crude oil were (30.0), (29.9), (29.4) respectively, at 24 °c, 96 hrs evaporation time, and other parameters were the same above (point 4). 6increasing the pressure to 8 bar over the surface of blend crude oil covered with surfactant, covered with polymer and uncovered blend crude oil gave percentage evaporation losses (zero%), (0.01%), (0.16%) respectively, at 24 °c, and for 24 hrs evaporation time at the same above conditions (point 4). 7the percentage evaporation losses for fixed roof , external moving roof, fixed roof with internal moving roof were (0.507%), (0.477%), (0.453%) respectively without surfactant and polymer. but with surfactant or polymer for above three roof types gave (0.299%, 0.388%), (0.283%, 0.365%), (0.266%, 0.347%) respectively at 16 °c, 120 hours evaporation time, for the same above other conditions (point 4). 8the addition of either polymer or surfactant minimizing the importance of proposed tanks types. 9in continuous circulation of blend crude oil (i.e. filling and discharge) for crude oil covered with surfactant, polymer and uncovered blend crude oil gave percentage evaporation losses, (0.328%), (0.378%), (0.45%) respectively at 24 °c, 96 hrs evaporation time , 143 cm 2 surface area, 1072.5 cm 3 dead space, 32 cm height of crude oil. references 1. voc emissions from volatile organic liquid storage tanks background information for proposed standards, epa-450/3-81-003a, u.s. environmental protection agency, research triangle park, nc, july 1984. 2. texas commission on environmental quality." technical guidance package for: chemical source. storage tanks, february 2001. 3. bradly, h.b., “petroleum engineering handbook”, 1 st printing, society of petroleum engineering, texas, usa, 1987. 4. sjoblom, j., aske, n., auflem, i.h., brandal, o., havre, t.e., soether, o., westvik, a., johnsen, e.e., kallevik, h., 2002. our current understanding of water in crude oil emulsions. recent characterization techniques and high pressure performance. 5. zemam, m.n., “reducing crude oil evaporation in storage tank,” m.sc thesis, baghdad university, chemical engineering department, 2007. 6. davies, j.t., interfacial phenomena, second edition, new york and london, 1963. 7. smith, j.m., introduction to chemical engineering thermodynamics, fourth edition, new york, 1988. 8. adamson, a.w., physical chemistry of surfaces, united states of america, 1976. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.20 no.1 (march 2019) 15 – 22 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: safa nabeel abdulqahar, email: safanabeel.abdulqahar@yahoo.com, majid i. abdulwahab, email: majid.abdulwahab@yahoo.co.uk, khalid k. hummadi, email: drkhalidkhazal@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. reuse of spent hydrotreating catalyst of the middle petroleum fractions safa nabeel abdulqahar, majid i. abdulwahab and khalid k. hummadi chemical engineering department-university of baghdad abstract reuse of spent hydrodesulphurization (hds) of middle petroleum fractions catalyst como/γal2o3 was accomplished via removal of coke and contaminants such as vanadium, iron, nickel, and sulfur. three processes were adopted; extraction, leaching, decoking. soluble and insoluble coke was removed. leaching step used three different solvents (oxalic acid, ammonium peroxydisulfate and oxalic acid + h2o2) in separate in order to remove contaminant metals (v, s, ni and fe). the effect of soluble coke removal on leaching step was studied. it was found that the removal of soluble coke significantly enhances the leaching of contaminants and barely affected the removal of active metals (co and mo). it was found that the best route (sequence) was soluble coke extraction followed by contaminants leaching then decoking process and the best leaching solvent was oxalic acid. according to this determination, the removed contaminants were 79.9 % for sulfur, 13.69% for vanadium, 82.27 % for iron, and 76.34 % for nickel. the active components loss accompanied with this process were 5.08 % for cobalt and 6.88% for molybdenum. leaching process conditions (leaching solvent concentration, temperature and leaching time) were studied to determine the best-operating conditions. the rejuvenated catalyst activity was examined by a pilot scale hds unit of naphtha. sulfur content removal of naphtha was found to be 85.56 % for single pass operation under typical operating conditions of refinery hds unit of naphtha which are 1 ml/min feed flow rate, 200 h2/hc ratio, 32 bar operating pressure and 320 °c operating temperature. keywords: catalyst rejuvenation, spent catalyst, hydrodesulphurization, extraction, leaching, catalyst activity. received on 28/11/8102, accepted on 20/01/8102, published on 30/03/8109 https://doi.org/10.31699/ijcpe.2019.1.3 1introduction clean fuels are mainly produced via catalytic hydrotreating processes ‎[1]. the catalyst used in these processes consists of an active metal (mo), carriers (alumina) and promoters (co or ni). hydrotreating processes include hydrodemetallization, hydrodenitrogenation, and hydrodesulphurization, these reactions remove the presented metals, nitrogen, and sulfur in the feed streams. these processes produce the major amount of hazardous solid wastes (spent catalyst)‎[2]. however, these catalysts lose activity with time due to fouling resulting from the formation of deposited carbonaceous on the catalyst active sites and deposition of heavy metals (such as nickel and vanadium) from the feedstock. poisoning and sintering are other causes of catalyst deactivation‎[3], ‎[4], ‎[5]. poisoning is caused by the accumulation of impurities attracted to the catalyst active sites by strong chemisorption. sintering results from decreasing of catalyst surface area and porosity which is usually associated with high temperature. high temperature may also lead to phase transformation of catalytic components and support ‎[6]. hydroprocessing spent catalyst represents a dangerous environmental issue. metals present in the catalyst (co, mo, ni, and v) could be leached when the spent catalyst is disposed and brought into contact with water and this, in turn, brings harmful pollutants. some reports recorded the liberation of generated hazardous gases as a result of the contact between water and disposed of spent catalyst ‎[7]. hydroprocessing catalyst has different lifetimes depending on the process in which it is applied. the halflife time values are 1-2 years for atmospheric or vacuum gas oils processing, 0.5-1 years for residue processing, and 5 plus years for naphtha processing ‎[5]. mainly, there are two sources for contaminants brought to the catalyst during hydroprocessing operations: the feed which is the source for v, ni, na and arsenic, and the additives used during processing which are the source for silicon and lead ‎[4]. the amount of produced spent catalyst (with 5-20 wt% c and 7-15% s) depends on the fresh hydrotreating catalyst used. this amount is 120,000 ton based on a dry basis and 150,000 ton based on total weight (includes coke, sulfur, and water),‎[5]. therefore, attention has been focused worldwide on developing different methods of handling spent catalysts. https://doi.org/10.31699/ijcpe.2019.1.3 s. n. abdulqahar, et al./ iraqi journal of chemical and petroleum engineering 20,1 (2019) 15 – 22 61 a comprehensive review of the literature on the subject revealed that the following options are available to resolve the problem. the most common options are disposal as landfill, recovery of metals, reactivation/rejuvenation and reuse of spent catalysts, and production of valuable products starting from the spent catalyst as a raw material. selection of an option depends upon its technical and economic feasibility. for disposal as landfill, this treatment method is, however, highly energy intensive and very expensive and they do not offer a profitable solution to the waste disposal problem‎[6], ‎[7]. metal recovery is technically viable, but the fluctuation in prices for the recovered materials sometimes renders the process uneconomical. moreover, the current technologies available for this option are themselves a potential source of chemical pollution arising from the chemicals used to leach the metals; hence the application of this option is limited. despite the conventional methods using nitrogen/air mixture remove coke completely, complete reactivation could not be attained since the metallic contaminants will not be removed from catalyst surface by these methods which in turn resist the diffusion of reactants ‎[7]. the regeneration/rejuvenation option is considered to be the most attractive approach and has potential advantages from both economic and environmental points of view. in this process, both contaminants (coke and metals deposits) are removed from the spent catalyst and it can be reused. in recent studies, attention was focused on the hydroprocessing spent catalysts regeneration. a few processes for removal of metals and coke deposits have been reported in patents literature but information on selective removal of the contaminant metal was relatively scarce. selective leaching of contaminant metals using different organic acids was compared by sadeek, 2014 ‎[8]. he founded that oxalic acid was the optimum leachate for the remaining contaminants on the surface of the catalyst. kinetics and mechanism of leaching metal sulfides from spent catalyst were also investigated by marafi, 1989. he founded that 0.33-0.1 m oxalic acid had a small effect on metal leaching rate. the main goal of the present work is to study the rejuvenation of spent hydrodesulphurization catalyst (como/γal2o3). different rejuvenation stages such as extraction of soluble coke, leaching of contaminants and decoking have to be investigated. attention will be focused on the leaching efficiency of solvents, the preferred leaching route for selective leaching of the deposited metal contaminants, the effect of leaching treatment on the concentration and distribution of catalytically active catalyst metals (co and mo) originally present in the catalyst and also on the morphology of alumina support. 2experimental work the present work includes three routes to reactivate the spent hydrodesulphurization catalyst. each route consists of three stages: extraction of soluble coke using n-hexane as a solvent, leaching of contaminants (undesired metals) from the catalyst using different solvents and removing of insoluble coke. 2.1. raw materials a. hydrodesulphurization spent catalyst a sample of spent hds catalysts (como/ɣal2o3) was brought from the kerosene hydrodesulphurization unit at baiji refinery plant. the catalyst pellets had a cylindrical shape with approximate dimensions of 5.5 x 2 mm. the composition of the spent catalyst was determined using xrf spectrometer in iraqi-german geological laboratory at geological department / college of science / university of baghdad. table1 shows the chemical analysis of the spent hds catalyst. table 1. characteristics of spent hds catalyst property value co % 3.915 mo % 8.57 ni % 0.04674 fe % 0.4476 s % 1.026 v % 0.0038 surface area 216.96 m 2 /g pore volume 0.348 b. solvents the solvents were n-hexane, oxalic acid, hydrogen peroxide, and ammonium peroxydisulfate, ‎[9], ‎[8], ‎[10], ‎[11], ‎[4] 2.2. apparatus three processes were adopted in this work: soluble coke removal, leaching of metals and removal of insoluble coke. apparatus used for these processes were. a. catalyst washing reciprocating shaker was used for catalyst washing using sweet heavy naphtha to remove dust and rust accumulated on the spent catalyst. 30 g of the catalyst was mixed with 300 ml of sweet heavy naphtha at room temperature for 90 min, and then the catalyst pellets were filtered and dried at 100 °c for 24 h. s. n. abdulqahar, et al./ iraqi journal of chemical and petroleum engineering 20,1 (2019) 15 – 22 61 b. soluble coke removal fig. 1 shows soxhlet apparatus ‎[12] used for soluble coke removal step. this apparatus consists of a still pot, thimble, distillation path, catalyst, siphon top, siphon exit, and condenser. the extraction step was conducted by putting 30 g of deoiled catalyst in the thimble with 150 ml of n-hexane in the still pot at 69 °c (boiling point of nhexane) for 6 hours in order to extract the soluble coke. then the catalyst was dried at 100 °c for 24 hours. fig. 1. schematic diagram of the soxhlet apparatus 2.3. leaching of metals three necks round flask with a thermometer and magnetic stirrer were used for metals leaching. three leachates in separate were used for leaching. the ratio of catalyst to leachate solution ratio was 1/10 g at various temperatures of 25, 50, 70, and 90 °c. the time of leaching were 15, 30, 60, 90 and 120 min and the concentrations were 0.04, 0.06, 0.0[, 0.12 and 0.16 m. stirring was fixed at 200 rpm (excessive stirring tends to break catalyst extrudes, and a slow stirring decreases leaching yield). after each leaching process, the leached catalyst ph was adjusted to 7 by filtration and washing with water, then dried at 150 °c for 2 h. 2.4. removing of insoluble coke muffle – furnace was used for insoluble coke removal. the catalyst was heated to 500 °c for 4 h at a heating rate of 1 °c/min. 3results and discussion 3.1. removal of soluble coke removal of soluble coke played an important role in the catalyst rejuvenation as a result of enhancement in porosity and surface area, and this, in turn, will promote the removal of contaminants step. effect of soluble coke removal on the catalyst characteristics is shown in table 2 which shows the difference between leached metals percentage with and without soluble coke extraction stage. the enhancement percent between the two parts was 27.9% for fe and the smallest leaching percent was 0.62% for mo. the leaching percentage was different for different metals according to their solubility in the used leachate. table 2. effect of soluble coke removal on metals leaching with oxalic acid (0.08 m, 30 min, 25 °c and 200 rpm) element wt. % leached without soluble coke extraction wt.% leached with soluble coke extraction s 60.59 70.79 v 3.39 13.69 fe 54.37 82.27 co 3.93 5.08 ni 63.78 76.34 mo 6.26 6.88 3.2. removal of insoluble coke process careful control of decoking conditions is essential to avoid permanent damage to the catalyst as a result of sintering and phase transformation. the removal of insoluble coke was carried out in a furnace at 500 ᵒc for 4 hours with a heating rate of 1 ᵒc/min. the slow heating rate was selected in order to increase the activity of the recovered catalyst. the catalyst was weighted before and after the decoking process in order to estimate the percent of the volatile matter which was found to be 12 wt% of the spent catalyst sample. 3.3. leaching of metals catalyst active surface area obviously reduced as a result of pores entrance plugging via the contaminants accumulating at the catalyst pellet. to reactivate the catalyst, both the coke and metal deposits have to be removed from the catalyst surface. in order to rejuvenate the catalyst efficiently, diffusion resistance represented by contaminant metals should be removed and attention should be paid for keeping the original physical and chemical properties of the catalyst. mechanism of contaminants leaching from spent catalyst could be explained as follow; the solvent diffuses through the interface to the solid surface of the catalyst, then the diffused solvent reacts with presented solute (contaminants) in the solid phase to form the products those, in turn, diffuse back to the solvent bulk. table 3 compares the characteristics of the spent catalyst before rejuvenation with those of fresh catalyst. table 3. physical and chemical properties of spent and fresh como/ɣal2o3 catalyst property value in the fresh catalyst value in the spent catalyst co % 4.048 3.915 mo % 10.28 8.57 ni % 0.03413 0.04674 fe % 0.1896 0.4476 s % 0.5632 1.026 v % 0.0032 0.0038 surface area 314.79 216.96 pore volume 0.410158 0.348 s. n. abdulqahar, et al./ iraqi journal of chemical and petroleum engineering 20,1 (2019) 15 – 22 61 this table shows that considerable amounts of metals (v, ni, fe, and s) had been accumulated on the spent catalyst. the presence of contaminant metals along with the catalytic metals (co and mo) is confirmed by x-ray fluorescence. the surface area of the spent catalyst is about 31.08 % and the pore volume is about 15.15 % lower than those of the fresh catalyst. it can be seen that vanadium has concentrated in a high amount near the interior surface of the catalyst. nickel penetrated further into the interior of the catalyst pellet due to its smaller molecule size. the active catalyst metals (co and mo) are uniformly distributed within the pellet ‎[9] 3.4. comparative study of the sequence of reactivation stages in the present work, three routes with three solutions were used as shown in fig. 2 to reactivate the spent hds catalyst. the primary aims of the study were to compare the effectiveness of these routes (route a, route b, and route c) for selective leaching the deposited metals from spent catalyst and to recommend the preferred leaching route. fig. 2. percent of leached metals in route a (extraction of soluble coke decoking leaching of metals) a. effect of solvent type the sequence of stages in route a was as follows; the deoiled spent catalyst was extracted by n-hexane to remove soluble coke then it was decoked at a controlled temperature, and the last step was the leaching of the catalyst. three different solvents were used in the leaching step in order to find out which solvent is suitable for the leaching step, these solvents are; oxalic acid, ammonium peroxydisulfate, and (oxalic acid + hydrogen peroxide) under the same conditions of 30 °c, 30 min, 200 rpm. oxalic acid and ammonium peroxydisulfate with 0.1 m for each were prepared. the ph of the prepared oxalic acid solution was 1.46 while for ammonium peroxydisulfate, ph was 1.54. one ml of hydrogen peroxide was added to 50 ml of oxalic acid the resulted ph was 1.41. figure 2 shows the comparison between the three used solvents results for route a. it is obvious that removal of ni, fe, and v shows a slight response to the type of solvent used, while sulfur removal was strongly affected by the solvent. this can be attributed to the effect of ph of the solution (between 1.54 and 1.46). the addition of oxidizing agent (h2o2) has only a slight effect on the removal of sulfur. in the case of molybdenum, it was found that leaching percentage was increased when using different solvents in the order ammonium peroxydisulfate > oxalic acid > oxalic acid + hydrogen peroxide. so, it can be concluded that oxalic acid is the most suitable solvent for leaching since it is characterized with high ability to remove contaminants (s, v, fe, and ni) and low ability to remove active metals (co and mo). in route b, the deoiled spent catalyst was leached with the same three solutions in route a (oxalic acid, ammonium peroxydisulfate, and oxalic acid + hydrogen peroxide), and then the soluble coke was extracted by nhexane. the last stage in this route was the insoluble coke removal by muffle-furnace under controlled temperature. the operating conditions of the leaching stage were the same as those used in route a. the results of this route were presented in fig. 3. the contaminants (s, v, ni, and fe) and active catalyst metals (co and mo) showed similar behavior to that shown in route a. so, the optimum solution is oxalic acid. fig. 3. percentage of leached metals in route b the sequence of stages in route c was the soluble coke was extracted from the spent catalyst after deoiling step. then, the metals were leached by the following solutions (ammonium peroxydisulfate, oxalic acid, and oxalic acid + hydrogen peroxide) the conditions were the same as those used in route a. the last step in this route was the removal of insoluble coke by muffle-furnace. the percentage of removed metals was shown in fig. 4. this figure shows that the same behavior followed by route a and b. again oxalic acid was the suitable leaching solvent. s. n. abdulqahar, et al./ iraqi journal of chemical and petroleum engineering 20,1 (2019) 15 – 22 61 fig. 4. percentage of leached metals in route c 3.5. best leaching conditions from the above discussion, the best leaching solvent was oxalic acid (figs. 2 – 4). these results confirm the result reached by sadeek, 2014 ‎[8] who examined three solvents for leaching of contaminants using nimo/ɣal2o3. these solvents were oxalic acid, benzoic acid and boric acid at different concentrations. he concluded that oxalic acid is the optimum solvent for leaching from spent catalyst. fig. 5 represents the removal of each contaminant by oxalic acid for route a, b, and c. it is clear that the optimal route is route c since the removal of contaminants (s, v, fe, and ni) is relatively large while the loss of active metals (co and mo) is relatively small. pereiraet. et.al 2011 ‎[9] adopted the same sequence of stages in route c (extraction of soluble coke → leaching of metals → removal of insoluble coke). after the determination of best solvent for optimum route, the favorable leaching conditions were determined experimentally by studying temperature, leachate concentration and leaching time in order to attain suitable conditions for catalyst rejuvenation. stirring rate was fixed at 200 rpm. fig. 5. comparison among routes a, b, and c for metal removal a. effect of oxalic acid concentration internal active surface area inside the pores significantly reduced via the pore entrance plugging caused by the contaminants accumulated at the catalyst surface. effect of oxalic acid concentration on metals leaching was studied at 30°c for 30 min and 200 rpm stirring speed, for different concentrations of oxalic acid (0.04, 0.06, 0.08, 0.12 and 0.16 m). the metals in spent hds catalyst are presented as sulfides. leaching occurred with the chemical reaction between the metal sulfide and solvent as shown in reaction (1) ‎[13] ms2 + 4chcoo → m (ooc.ch3)4 + 2h2s (1) where m refers to the metal in the catalyst the influence of the oxalic acid concentration on the contaminants leaching is presented in fig. 6. for vanadium, the leached contaminants percentage increases with increase in oxalic acid concentration, the removal was raised from 13.16% at acid concentration of 0.04 m to 21.05% at acid concentration of 0.16 m. the leached percentage of iron showed a slight increase with increasing in oxalic acid concentration; this was from 82.46% to 85.84%. on the other hand, as oxalic acid concentration increased, the leached percentage of cobalt was nearly unaffected around and remained at 40%. similar to cobalt, the leached percentage of nickel and molybdenum was nearly constant with oxalic acid concentration to be around 82% for nickel and 26% for molybdenum. this behavior is consistent with literature ‎[9]. in spite of increasing removal of contaminants of spent catalyst (s and v) by increasing acid concentration, increasing in acid concentration may enhance the removal of active catalyst metals (co and mo). so, the best concentration was 0.08 m of oxalic acid which leached as large as possible of the contaminants and leached as small amount as possible of the active metals. fig. 6. metal removal at 30 °c and 30 min 0 20 40 60 80 100 0 0.05 0.1 0.15 0.2 % m e ta l re m o v a l oxalic acid concentration, m v fe co ni mo s. n. abdulqahar, et al./ iraqi journal of chemical and petroleum engineering 20,1 (2019) 15 – 22 02 b. effect of leaching temperature effect of temperature on the leaching process is presented in fig. 7. this effect was examined for different temperatures (30, 50, 70 and 90 °c) at 0.08 m of oxalic acid for 30 min and 200 rpm stirring speed. from figure 7, the leached percentage of v increased with temperature, while the removal of fe, co, ni, and mo showed a slight response to temperature. the best leaching temperature was 50 °c since it removed a high percentage of contaminants and a low percentage of active metals. this value is consistent with the literature [6]. the increasing in leaching rate with temperature is due to the direct proportion of reaction rate and temperature according to arrhenius equation ‎[14]. k = a. (2) where: k is the reaction rate constant. the temperature may also affect the leaching rate by enhancing diffusion of solvent into catalyst pores since the viscosity decreases as temperature increases and this, in turn, promote the leaching rate. fig. 7. metal removal at 0.08 m and 30 min c. effect of leaching time effect of leaching time on the contaminants removal was examined at 30 °c and 0.08 m oxalic acid concentration for different periods of time (15, 30, 60 and 120 min). effect of time is presented in figure 8. this figure showed that the leaching percentage increased with time since longer contact time between contaminants and solution resulted in the increasing movement of contaminant toward oxalic acid. in general, the best time was 30 min which leached the contaminants as large as possible maintaining the active catalyst metals (co and mo) as low as possible. fig. 8. the percentage of metal removal versus time at 0.08 m and 30 °c 3.7. test of activity of rejuvenated catalyst in order to determine the activity of rejuvenated catalyst, reduction in naphtha sulfur content was measured for both spent and rejuvenated catalyst. the test was accomplished in a pilot scale hydrodesulfurization unit in prdc with 17.5 mm inside diameter and 25.4 mm outside diameter with 300 mm length 361l stainless steel reactor. fifty grams of spent catalyst were uploaded to the reactor and naphtha was fed at 1 ml/min flow rate. operating conditions were 320 °c temperature, 200 h2/hc ratios, and 32 bars. sulfur content reduced by 75.4 % for one pass hydrodesulphurization. for rejuvenated catalyst test, fifty grams of rejuvenated catalyst were uploaded to the same reactor. under the same operating conditions, sulfur content of feed naphtha reduced by 85.55 % for one pass hydrodesulphurization. the difference between these values showed that the activity of rejuvenated catalyst enhanced by 10.15 % sulfur content removal under the best rejuvenation conditions. 4conclusion 1for spent hds catalyst rejuvenation, the effective removal of most important contaminants such as s, fe, and v was enhanced more than 15 % when the soluble coke was removed. 2oxalic acid is a very suitable solvent in reactivation of spent hds catalyst. 3the best route for rejuvenation of spent catalyst was the extraction of soluble coke followed by leaching of metals then finally decoking stage. 4the best leaching with oxalic acid conditions was 0.08 m at a temperature of 50 ᵒc and leaching time of 30 min. 5the activity of spent hds catalyst enhanced to more than 10 %. 6rejuvenation of spent catalyst can give a catalyst with active metals content only less than 10 % compared with fresh catalyst and the other characteristics remain nearly the same. s. n. abdulqahar, et al./ iraqi journal of chemical and petroleum engineering 20,1 (2019) 15 – 22 06 references [1] l. wu and y. liu, “environmental impacts of hydrotreating processes for the production of clean fuels based on life cycle assessment,” vol. 164, pp. 352–360, 2016. [2] m. mara and a. stanislaus, “waste catalyst utilization : extraction of valuable metals from spent hydroprocessing catalysts by ultrasonic-assisted leaching with acids,” ind. eng. chem. res., pp. 9495–9501, 2011. [3] j. r. chang, s. l. chang, and t. b. lin, “γ-aluminasupported pt catalysts for aromatics reduction: a structural investigation of sulfur poisoning catalyst deactivation,” j. catal., vol. 169, no. 1, pp. 338–346, 1997. [4] a. stanislaus, handbook of spent. 2016. [5] p. dufresne, “hydroprocessing catalysts regeneration and recycling,” vol. 322, pp. 67–75, 2007. [6] m. marafi, “studies on deactivation and reactivation of spent hydroprocessing catalyst,” 1996. [7] m. marafi and a. stanislaus, “options and processes for spent catalyst handling and utilization,” vol. 101, pp. 123–132, 2003. [8] s. a. sadeek, h. s. ahmed, e. a. elshamy, h. a. el sayed, and a. a. abd el rahman, “hydrotreating of waste lube oil by rejuvenated spent hydrotreating catalyst,” egypt. j. pet., vol. 23, no. 1, pp. 53–60, 2014. [9] c. n. da s. e j. c. a. alexandre luiz de souza pereira, “quim. nova,” quim. nova, vol. 34, no. 10, pp. 1704–1716, 2011. [10] j. s. yoo, “metal recovery and rejuvenation of metal-loaded spent catalysts,” catal. today, vol. 44, no. 1–4, pp. 27–46, 1998. [11] w. wang, s. wang, y. wang, h. liu, and z. wang, “a new approach to deep desulfurization of gasoline by electrochemically catalytic oxidation and extraction,” fuel process. technol., vol. 88, pp. 1002–1008, 2007. [12] h. a. abdullah, a. hauser, f. a. ali, and a. aladwani, “optimal conditions for coke extraction of spent catalyst by accelerated solvent extraction compared to soxhlet,” energy and fuels, vol. 20, no. 1, pp. 320–323, 2006. [13] e. s. p. b. v, m. marafi, a. stanislaus, c. j. mumford, and m. fahim, “regeneration of spent hydroprocessing metals removal catalysts :,” vol. 47, no. 3989, pp. 85–96, 1989. [14] o. levenspiel, chemical reaction engineering o. levenspiel wiley. third edition, vol. 19. 1999. اعادة تدوير العامل المساعد المستهلك والمستخدم في هدرجة المستقطرات الوسطية الخالصة اعادة استخدام العامل المساعد المستخدم في ىدرجة المستقطرات الوسطية الزالة الكبيريت como/ᵞal2o3 انجزت بواسطة ازالة الكاربون والمموثات االخرى كالفناديوم, الحديد, النيكل والكبريت. تم ازالة الكاربون. تمت ازالة كل من الكربون استخدام ثالث عمميات في المعالجة وىي = االنتزاع , االستخالص, و القابل لمذوبان والكاربون الغير قابل لمذوبان في خطوة االستخالص, وتم استخدام ثالثة مذيبات بصورة منفصمة بيروكسيد الييدروجين. +وىي حامض االوكزالك, االمونيوم البيروكسي ثنائي السمفات, وحامض االوكزالك ازالة الكاربون الذائب ووجد ان ازالتو ميمة في تعزيز عممية االنتزاع لممموثات وتاثيرىا قميل تمت دراسة تاثير بالنسبة لممعادن الفعالة لمعامل المساعد ) الكوبمت والمولبدنيوم (. وجد ان افضل مسار ىو ازالة الكاربون الذائب ب كان حامض االوكزالك. وفقا ليذه العممية متبوعة بانتزاع المموثات وازالة الكاربون الغير ذائب وافضل مذي % لمنيكل. 9.67:% لمحديد, و :2.2;% لمفناديوم, >96.9% لمكبريت, >.>:كانت نسبة ازالة المموثات ىي % لممولبدنيوم.;;.9% لمكوبمت, و ;..8كمية الفقدان في المادة الفعالة بسبب ىذه العممية كانت https://www.sciencedirect.com/science/article/pii/s0016236115010170 https://www.sciencedirect.com/science/article/pii/s0016236115010170 https://www.sciencedirect.com/science/article/pii/s0016236115010170 https://www.sciencedirect.com/science/article/pii/s0016236115010170 https://pubs.acs.org/doi/abs/10.1021/ie200789u https://pubs.acs.org/doi/abs/10.1021/ie200789u https://pubs.acs.org/doi/abs/10.1021/ie200789u https://pubs.acs.org/doi/abs/10.1021/ie200789u https://pubs.acs.org/doi/abs/10.1021/ie200789u https://www.sciencedirect.com/science/article/pii/s0021951797917097 https://www.sciencedirect.com/science/article/pii/s0021951797917097 https://www.sciencedirect.com/science/article/pii/s0021951797917097 https://www.sciencedirect.com/science/article/pii/s0021951797917097 https://www.sciencedirect.com/science/article/pii/s0021951797917097 https://www.sciencedirect.com/science/article/abs/pii/s0926860x07000099 https://www.sciencedirect.com/science/article/abs/pii/s0926860x07000099 https://ethos.bl.uk/orderdetails.do?uin=uk.bl.ethos.388516 https://ethos.bl.uk/orderdetails.do?uin=uk.bl.ethos.388516 https://www.sciencedirect.com/science/article/pii/s0304389403001456 https://www.sciencedirect.com/science/article/pii/s0304389403001456 https://www.sciencedirect.com/science/article/pii/s0304389403001456 https://www.sciencedirect.com/science/article/pii/s1110062114000105 https://www.sciencedirect.com/science/article/pii/s1110062114000105 https://www.sciencedirect.com/science/article/pii/s1110062114000105 https://www.sciencedirect.com/science/article/pii/s1110062114000105 https://www.sciencedirect.com/science/article/pii/s1110062114000105 https://www.sciencedirect.com/science/article/pii/s0920586198001710 https://www.sciencedirect.com/science/article/pii/s0920586198001710 https://www.sciencedirect.com/science/article/pii/s0920586198001710 https://www.sciencedirect.com/science/article/pii/s0378382007001178 https://www.sciencedirect.com/science/article/pii/s0378382007001178 https://www.sciencedirect.com/science/article/pii/s0378382007001178 https://www.sciencedirect.com/science/article/pii/s0378382007001178 https://www.sciencedirect.com/science/article/pii/s0378382007001178 https://pubs.acs.org/doi/abs/10.1021/ef050227l https://pubs.acs.org/doi/abs/10.1021/ef050227l https://pubs.acs.org/doi/abs/10.1021/ef050227l https://pubs.acs.org/doi/abs/10.1021/ef050227l https://pubs.acs.org/doi/abs/10.1021/ef050227l https://www.sciencedirect.com/science/article/pii/s0166983400832650 https://www.sciencedirect.com/science/article/pii/s0166983400832650 https://www.sciencedirect.com/science/article/pii/s0166983400832650 https://www.sciencedirect.com/science/article/pii/s0166983400832650 https://4lfonsina.files.wordpress.com/2012/11/levenspiel-chemical-reaction-engineering.pdf https://4lfonsina.files.wordpress.com/2012/11/levenspiel-chemical-reaction-engineering.pdf s. n. abdulqahar, et al./ iraqi journal of chemical and petroleum engineering 20,1 (2019) 15 – 22 00 تركيز المذيب المستخدم في االنتزاع, درجة الحرارة, وقت العممية ( من تمت دراسة ظروف عممية االنتزاع ) اجل تحديد افضل الظروف. تم اختبار فعالية العامل المساعد المنشط في وحدة نطاق تجريبي لميدرجة الزالة الكبريت لمنفثا. نسبة الكبريت روف تشغيمية مثالية لوحدة ازالة الكبريت % لعممية تمرير واحدة لمنفثا تحت ظ8.89;المزال من النفثا كانت , ضغط ..2ىيدروكاربونات =\دقيقة, نسبة ىيدروجن\مل 9باليدرجة لممصافي النفطية والمتمثمة بمعدل جريان درجة سميميزية. .62بار, ورجة حرارة 62 باليدرجة, استخالص, انتزاع, فعالية العامل المساعد الكممات الدالة= اعادة تدوير العامل المساعد, العامل المساعد المستيمك, ازالة الكبريت iraqi journal of chemical and petroleum engineering vol.17 no.3 (september 2016) 110 issn: 1997-4884 geological model of khasib reservoircentral area/east baghdad field mohammed saleh al-jawad * and khalid ahmed kareem ** * petroleum technology engineering department, college of engineering, university of technology ** petroleum engineering department, college of engineering, university of baghdad abstract the geological modeling has been constructed by using petrel e&p software to incorporate data, for improved three-dimensional models of porosity model, water saturation, permeability estimated from core data, well log interpretation, and fault analysis modeling. three-dimensional geological models attributed with physical properties constructed from primary geological data. the reservoir contains a huge hydrocarbon accumulation, a unique geological model characterization with faults, high heterogeneity, and a very complex field in nature. the results of this study show that the three-dimensional geological model of khasib reservoir, to build the reservoir model starting with evaluation of reservoir to interpretation of well log by using ip software for 14 wells, defining and divided the layers based on the gr log and resistivity log to nine layers and then maintained the fault model for a divided central area to four regions. compared porosity log with porosity core to estimate correction porosity and enter this value to predict the permeability value for each layer by using fzi, and rqi method. the model containing faults, horizons, zones, and layers depending on this data to make gridding by using pillar gridding. this paper presents a geological modeling and an uncertainty analysis for stock-tank original oil in place. the distribution of the faults is also discussed. key words: porosity, permeability, water saturation. introduction a great portion of the world’s oil reserves is contained in carbonate reservoirs, which play an important role in oil exploration and makes a large contribution toward oil production worldwide. however, characterization of carbonate reservoir is very complex as compared to conventional reservoirs. east baghdad field [1] was discovered by the iraq national oil company (inoc) in 1974 with extension of alssaouira area (south east) to alnibayia (north west), in 1975 was drilled first well, east baghdad -1 (eb-1) approximately 20 km in the east of baghdad city, which reached to the adaiya formation at depth 4842 m of the early jurassic. since then, up to eighty wells were drilled reach 38 university of baghdad college of engineering iraqi journal of chemical and petroleum engineering geological model of khasib reservoircentral area/east baghdad field 2 ijcpe vol.17 no.3 (september 2016) -available online at: www.iasj.net wells to zuiber formation and 41 wells to kifel formation include 19 wells are directional, have been drilled from 1980 to 1989 as exploration and development wells in the al-rashdiya area, about two third of which are located in al-rashdiya and urban areas. the geological model is often performed making by using of the static data, i.e. seismic interpretation, logs interpretation and core analysis data, dynamic data is used to consistency of the model and its ability to reproduce the observed reservoir performance. a petrophysical model was created from the core analysis and logs interpretation in one dimension. the geological model needed to distribute the information data in 3d. fault model the proposed fault pattern includes the main faulting parallel to the nw-se axis of the structure, and secondary system associated to the main one including nnw-sse and e-w trending faults [2]. the full-field geological model was split into four regional models, each bounded by sealing faults, as shown in figure 1 and the secondary faults are not sealed. the central area is divided into four separate equilibrium region, which have unique fluid contacts identified by the equilibrium region number eqlnum. the khasib fault model analysis depends on [3]. petrophysical modeling the object of the petrophysical variable need to estimation a reservoir, include (porosity (ø), hydrocarbon saturation, thickness (h), and permeability (k)), an addition to the parameter include (formation temperature, reservoir pressure, and lithology of formation) applied in the evaluation wells, completion wells, and production wells [4]. this section discussion of the methodology developed for petrophysical model and its application to khasib formation. the systematic approach presented in the following sections evaluates the combination of (porosity, permeability and irreducible water saturation) at each depth. fig. 1: 2dboundary and fault model porosity model 3d distribution of porosity was exported to the simulation from geological model. porosity data for khasib reservoir was obtained from (502) core samples analysis for seven wells are (eb-11, eb-14, eb-19, eb-25, eb-29, eb-35, and eb-74) and the well logs interpretation of most of them are available for thirteen wells. the well eb-35 is located on the northeastern flank of the anticline, and the other wells are located on the axis. the effective porosity data from core analysis and log interpretation was matched at the same interval, example wells eb-11, as shown in figure 3. the effective porosity log (øe) from ip program was scaled up by using arithmetic averaging and ‘as point’ http://www.iasj.net/ mohammed saleh al-jawad and khalid ahmed kareem -available online at: www.iasj.net ijcpe vol.17 no.3 (september 2016) 3 options in petrel, as shown in figure 2 for k2. fig. 2: 2d-porosity model for k2 unit permeability model the 3d permeability in 3d x-direction (kx), y-direction (ky) and z-direction (kz) were exported to the simulation from static model. permeability in ydirection (ky) was set equal to the xdirection (kx). the hydraulic flow unit (hu) can be used excessively as soon as a method in the rock typing and permeability calculation. hydraulic flow unit (hu) is relataed to flow zone indicator (fzi) and rock quality index (rqi). this method is effective in predicting permeability in the uncored section. in this study, the hu for hydrocarbon can calculate from the core analysis data .this method can be explained by [5], calculated the flow zone indicator (fzi) and reservoir quality index (rqi). the predicted permeability by the modified method was used in the geological model. equations 1, 2, 3 and 4 were used to calculate rqi, phiz (∅z) and fzi. √ ∅ …(1) ∅ ∅ ∅ …(2) ∅ √ ∅ ( ∅ ∅ ) …(3) ∅ ( ∅ ) …(4) all available cores from 7 wells (eb11, eb-14, eb-19, eb-25, eb-29, eb35, and eb-74) were used to be a database for hu classification. depending on the hu definitions obtained from the log-log plot for the rqi vs. (∅z), as shown in figure 4, this figure shows the hu approach which is applied to east baghdad oil fields / central area where three distinct hu are evident with different number of hu and defined by different fzi.the unit slope lines were drag related to the fzi that will be intercepted with the ∅z =1. the core samples that have a plot of the log permeability vs. porosity (∅), as shown in figure 5. fig. 3: log porosity vs. core porosity for well eb-11 http://www.iasj.net/ geological model of khasib reservoircentral area/east baghdad field 4 ijcpe vol.17 no.3 (september 2016) -available online at: www.iasj.net fig. 4: rqi vs. phiz (∅z) plot for different hu's fig. 5: porosity vs. permeability relationships for different hu's the relation between porosity and permeability for each rock type was illustrated using the power law model, correction coefficient was obtained for all rock types, and then permeability can be estimated accurately from the equation of curve for each rock type, permeability distribution as shown in figure 6. according to the core description in 7 wells khasib formation has been subdivided into three facies are vuggy (packstone – wackstone), not vuggy (packstone –wackstone), and wackstone – mudstone [6]. fig. 6: 2d-permeability model for k2 unit formation evaluation the interpretation of well logs was done by using interactive petrophysics program (ip) (an interactive program to carry out interpretations and log corrections for borehole environment and invasion effects). the interpretation of wells logs sets were used as input data to evaluate the carbonate rocks (khasib formation) for the wells under study. water saturation and hydrocarbon determination the target of using logging wells is to estimate oil or gas that found in the reservoir units, for example resistivity logs that used to estimate the true resistivity of the reservoir with using the bottom hole parameter, fluid mud, lithology of formation, and the invasion of the formation [7]. for clean formation the archie saturation equation can be written: http://www.iasj.net/ mohammed saleh al-jawad and khalid ahmed kareem -available online at: www.iasj.net ijcpe vol.17 no.3 (september 2016) 5 [ ∅ ] …(5) taking m=n=2, a=1, and rw=0.033 ohm.m at 150 °f which is admissible approximation, emphasizes the relation between the porosity (ø) and the formation resistivity (rt). these parameters have effective on calculation of water saturation and effect on the fluid contact and reserves calculation [8]. equation 5 can be used to determine the water saturation in the main zone. instead rt put rxo with the micro resistivity log to give the value of the sxo in flash zone, with mud filtrate rmf, express in equation form: [ ∅ ] …(6) the residual oil saturation (sor) and movable hydrocarbon (shr) are calculated from the following equations [9] [∅ ( )] …(7) [∅ ( )] …(8) formation analysis by well log interpretation 1. porosity analysis the effective porosity formation with better selective for neutron-density logs, to determine the formation properties. porosity was calculated by neutron-density logs, applying variable density with grain density =2.71gm/cc and maximum grain density =2.95 gm/cc for the wells [7]. porosity analysis, which is divided into effective porosity (φe), water filled porosity in the invaded zone (φe.sxo), and water filled porosity in the uninvited zone (φe.sw). the area between (φe.sxo) and (φe.sw) represents the movable hydrocarbon, but the area between (φe) and (φe.sw) represents the residual oil saturation, as shown in figure 5. 2. shale volume analysis the percentage of shale or the volume of clay (vcl) was mainly determined using the gamma ray data with the linear method as follows: ( ) ( ) …(9) volumetric calculation the stock tank oil intial in place (stoiip) is calculated by using a volumetric method applying formation volume factor (bo) obtained from pvt test results. once the petrophysical properties are simulated, the volumetric will have been computed. the calculated stoiip equals to 9,540 mmstb without cut-off (φe, sw, vsh) and 6,617.8 mmstb with cut-off according to the equation: ( ) …(10) fig. 7: fluid and formation analyses for well eb-35 (region/1) http://www.iasj.net/ geological model of khasib reservoircentral area/east baghdad field 6 ijcpe vol.17 no.3 (september 2016) -available online at: www.iasj.net conclusions  uncertainty in calculating stoiip compared with previous studies.  the oil water contact can divide into four fluids depend on four regions at well eb-35, eb-43, eb47, eb-33 in each region. nomenclatures symbols description unit φe effective porosity fraction swi irreducible water saturation fraction ρma matrix density gm/cc ρb formation bulk density gm/cc ρf fluid density gm/cc a, n,m archie’s parameters dimensionless sw water saturation fraction bo oil formation volume factor rbbl/stb boi intial oil formation volume factor rbbl/stb sor residual oil saturation fraction shr movable hydrocarbon fraction h thickness m a aera m 2 abbreviations ip interactive petrophysics software sp self potential log rw resistivity of water formation rmf resistivity of mud rt resistivity of uninvited zone rxo resistivity of invaded zone tf formation temperature gr gamma ray log rhob density log nphi neutron log ρb bulk density recorder by log ild deep induction log sflu spherically focused log msfl microspherically focused log dt digital sonic k sp coefficient stoiip stock tank oil initial in place pvt pressure volume temperature hu hydraulic flow unit rqi rock quality index fzi flow zone indicator references 1. japex study, 2006, "the technical evaluation report for the g&g study of the east baghdad field, central iraq". 2. total study, december 1981 "geological study of east baghdad field area 3 ". 3. japex study, september 2008, "final technical report of east baghdad field full-scale development study" 4. schlumberger; 1989: “log interpretation principles/ application”. 5. amaefule, j.o., altunbay, m., tiab, j., kersey, d.g., keelan, d.k., 1993, enhanced reservoir description: using core and log data to identify hydraulic (flow) units and predict permeability in uncored intervals / wells: spe annual technical conference and exhibition, spe 26436. http://www.iasj.net/ mohammed saleh al-jawad and khalid ahmed kareem -available online at: www.iasj.net ijcpe vol.17 no.3 (september 2016) 7 6. japex study, september 2008, "final technical report of east baghdad field full-scale development study". 7. schlumberger educational services, houston, tx. john h. doveton – kansas geological survy 1999 "basic of oil and gas analysis". 8. total study, december 1981, east baghdad field, area 3 "geological study". 9. asquith, g.b., and gibson, c.,1982, "basic well log analysis for geologists", 2nd ed., aapg, tulsa, oklahoma, 216. appendixes fig. 8: fluid and formation analyses for well eb-43 (region/2) fig. 9: fluid and formation analyses for well eb-47 (region/3) fig. 10: fluid and formation analyses for well eb-33 (region/4) http://www.iasj.net/ geological model of khasib reservoircentral area/east baghdad field 8 ijcpe vol.17 no.3 (september 2016) -available online at: www.iasj.net fig. 11: 2d-porosity model for k3 unit fig. 12: 2d-porosity model for k4 unit fig. 13: 2d-porosity model for k5 unit fig. 14: 2d-permeability model for k3 unit http://www.iasj.net/ mohammed saleh al-jawad and khalid ahmed kareem -available online at: www.iasj.net ijcpe vol.17 no.3 (september 2016) 9 fig. 15: 2d-permeability model for k4 unit fig. 16: 2d-permeability model for k5 unit fig. 17: 2d-water saturation model for k2 unit fig. 18: 2d-water saturation model for k3 unit http://www.iasj.net/ geological model of khasib reservoircentral area/east baghdad field 10 ijcpe vol.17 no.3 (september 2016) -available online at: www.iasj.net fig. 19: 2d-water saturation model for k4 unit fig. 20: 2d-water saturation model for k5 unit http://www.iasj.net/ ijcpe vol.9 no.3 (september 2008) iraqi journal of chemical and petroleum engineering vol.9 no.3 (september 2007) 17-24 issn: 1997-4884 impact of tigris river pollution on the performance of water treatment plants efficiencies in baghdad city janan n. hamza water resources engineering department, college of engineering, university of baghdad abstract the determination of river pollution impact on the performance of water treatment plants is achieved by two main objectives. the first is to study raw and treated water qualities and comparing them with standards and the second is to evaluate the treatment plants efficiency. the analyzed data were those water quality parameters in relation to physical, chemical and bacteriological characteristics for river water and produced water by seven water treatment plants located on tigris river passing through baghdad city. the results of this study indicated that all raw water characteristic are within the surface water standards established by iraqi and usa criteria except bacterial counts. tigris river water is of good quality to be treated at the intake of kwtp and tends to be of less quality as it flows to south of city, where it is highly polluted at intake of rwtp. the analysis of treated water quality parameters supplied by all water treatment plants indicated that most of these characteristics are within the iraqi criteria and who guide lines except for the produced in rwtp. rwtp exceeded the water quality standards which recommended by who particularly bacterial counts and turbidity. the analysis showed that all water treatment plants have little effect on the in removal of the most of inorganic chemicals pollutants, the increasing level of sulfate, hardness, and total dissolved solid in treated water could be related to the absence of any chemical treatment units in the conventional baghdad water treatment works, and to the increasing of the concentration of these variables in river water. the statistical analysis had indicated that the correlation coefficient between turbidity and total coliform bacteria in river water for kwtp, ewtp and krwtp were good, and begin to increase at other water treatment plants reaching rwtp because the water quality of the river is deteriorated as the river flow downstream in baghdad city. introduction water quality of tigris river at baghdad city the present average water demand in baghdad is about 2900 million liters per day; the city is being supplied with water from tigris river after conventional treatment (sedimentation, coagulation, filtration and chlorination) by water treatment plants. these plants are located on the banks of the tigris river along a distance of about (5060) km, the quality of the tigris water within the city area is being changed mainly due to disposal large quantities of wastewater from different sources and made it unsuitable for drinking purposes from view point of public health. mutlak [1] performed a surveying along tigris river passing therough baghdad city during the year 1977 and 1978, he evaluated the suitability of the river for different purposes, he concluded that bacterial counts of tigris river exceeded the standard recommended for various purposes. al-masri [2] evaluated some pollutants concentration in tigris river through baghdad city, the results have indicated that concentrations of total hardness, sulfate university of baghdad college of engineering iraqi journal of chemical and petroleum engineering removal of asasbn sdfs fs f sf sdfsdfsdf fsdfsdfsdfs fsdfsdfsd 2 ijcpe vol.9 no.3 (september 2008) and calcium exceeded the permissible limits established by the gdhe. abu-hammdeh [3] had studied tigris water quality and treated water at the water treatment plants in baghdad city. his study aimed to find out the suitability of tigris water quality for the use as a source for drinking water, the study indicate that tigris water was classified as a good and suitable source for drinking water in kwtp and ewtp intakes, and it was classified as a polluted and heavy polluted source in the other intakes. thus, its unsuitable to de used as a source for drinking water by using conventional water treatment plant and advanced treatment are required. nawar [4] had studied the variation of salty ions in tigris river as it pass through baghdad city during period 1990-1999. the results indicated that the maximum concentration of total hardness and sulfate in tigris river are above the allowable limits for (who, 1984) drinking water standards. the area of study is baghdad city, in which seven water treatment plants located on tigris river are to be studied as follow (al-karkh, east dijlah, karama, wathba, qadisiya, doura and al-rasheed) see fig. 1. the water quality parameters selected in this study are color, temperature, turbidity, total solids, suspended solids, total dissolved solid, and total hardness as caco3, alkalinity as caco3, ph, calcium, magnesium, chloride, sulfate, nitrate, nitrite, aluminum, iron, fluoride, total coliform bacteria and fecal coliform bacteria. the analyzed data were these water quality data for raw water (river water near intake) and those of the produced water by the plants during the year 2004. raw water quality criteria the iraqi directorate general of human environment set in 1967 [3] the limits of regulation of rivers and public waters from the pollution no.25, these criteria have been compared with those of u.s.a. set by the federal water pollution control administration [5] table 1. drinking water quality standards drinking water quality standards are used as measures to ensure high quality of drinking water supplies world health organization who [5] set down guidelines for drinking water which are intended to supersede both the european and international standards, this standard are shown in table 1. objectives the main objective of this study are the following: 1. evaluate raw and produced water quality among comparison with raw and drinking water standard respectively. 2. obtain some useful regression equations for total coliform bacteria production from turbidity which is easily obtained. data collection: data of this study were collected from the routine chemical and bacteriological water analysis data carried out by the laboratory of quality control of baghdad water supply administration for the year 2004. 1 2 3 4 5 7 6 8 9 10 11 12 13 14 16 17 20 21 23 26 2728 29 25 24 22 19 18 15 31 30 east of tigris baghdad tourst island a rm y canal ti gr is riv er d iy a la r iv e r k h a ir riv e r boundary of baghdad city 0 5 10km st. 1 2 3 4 5 6 7 8-31 east of tigris al-karama plant al-wathba plant al-kadissia plant al-dorra plant al-wihda plant al-rasheed plant waste sewages st. fig. (1) location of water treatment plants and waste sewages along tigris river passing through baghdad city upstrream rwtp. (after al-masri, 1986) fig. 1: location of water treatment plants and waste sewages along tigris river passing through baghdad city upstream rwtp. (after al-masri, 1986) ijcpe vol.9 no.3 (september 2008) table 1 raw and treated water quality standards [3,14and15] constituent or characteristic units raw water treated water iraqicriteria u.s.a. criteria iraqi stand. who gl 1984 physical color tcu normal 10 15 temperature c turbidity ntu <10 5 inorganic chemical total solid ts mg/l suspended solid tss mg/l total dissolved solid tds mg/l 1500 1000 total hardness th mg/l narrative 500 500 alkalinity mg/l narrative 170-200 hydrogen-ioncons. ph ph value 6.5-8.5 6.5-8.5 6.8-8.5 6.5-8.5 calcium ca mg/l 200 magnesium mg mg/l 50-150 chlorid cl mg/l 200+ 250 200-600 250 sulfate so4 mg/l 200+ 250 200-400 400 nitrate no3 mg/l 15 10 20 10 nitrite no2 mg/l 0.1 aluminium al mg/l 0.1 0.2 0.2 iron fe mg/l 0.3 0.3 0.5 0.3 fluoride f mg/l 0.02+ narrative 1.0 1.5 bacteriological coliform bacteria tc mpn/100ml 10000 0-5 fecal coliform fc = 2000 <1 results and discussion raw water quality the results clearly indicate that most raw water characteristics (physical and chemical variables) are within the permissible limits established by iraqi directorate general of human environment, ministry of health, gdhe, and federal water pollution control administration. physical properties of raw water: the color of the raw water is less than 5 cu indicates the non-necessity the color reduction process in the treatment plant operation. average monthly reading of raw water temperature is ranging from 12c-32c; temperature is the major environmental factor that affects the survival of bacteria in water. the temperature increase leads to kill most of the bacteria especially in summer time, while its survival chances increase in low temperature, evison [6] the raw water turbidity had shown a high variation during winter, and low variation in summer, it is ranging from 20ntu to 314ntu, turbidity is caused by the presence of suspended matter such as clay, silt, organic matter, and inorganic matter, it can carry nutrient to support microbial growth, clay and suspended matter can form a case to protect bacteria from the effect of sunlight and salinity, lechevallier [7] inorganic chemical the monthly analysis of the inorganic chemical in raw water show that all the analyzed parameter were within permissible limits except sulfate, the maximum concentration of sulfate was 309 ppm in qwtp while the minimum sulfate was 69ppm in kwtp (table 2 to table 8). the values recorded near intake of kwtp were the lowest values because kwtp is located upstream of al-thrathar tigris canal junction, for this reason the values of all parameter had increased at all water treatment plants which is downstream al-thrathar tigris canal junction. bacterial analysis: the behaviors of total coliform (tc) and fecal coliform (fc) bacteria in river water passing through baghdad city have been shown in fig. 2 to fig. 3. it could be noticed from both figures that there is a big differences between kwtp and rwtp in bacterial densities, the first station is located in the northern part of the city (the inlet of the river) while the second station rwtp is located in the southern part of the city (the outlet of the river). maximum and minimum monthly average for tc at kwtp 300 mpn/100ml and 100 mpn/100ml respectively while at rwtp they were 130000 mpn/100ml and 2000 mpn/100ml. maximum and minimum monthly average for fc at kwtp 130and 80 respectively while at rwtp they were 110000 mpn/100ml and 1800 mpn/100ml, removal of asasbn sdfs fs f sf sdfsdfsdf fsdfsdfsdfs fsdfsdfsd 4 ijcpe vol.9 no.3 (september 2008) 0 2000 4000 6000 8000 10000 12000 14000 16000 18000 20000 0 10 20 30 40 50 60 distance (km) f e c a l c o li fo r m b a c te r ia ( m p n /1 0 0 m l) permissible limits 0 10000 20000 30000 40000 50000 60000 70000 80000 0 10 20 30 40 50 60 distance (km) t o ta l c o li fo r m b a c te r ia ( m p n /1 0 0 m l) permissible limits bacterial counts recorded at rwtp were 330 times for tc higher that recorded at kwtp. presence of total coliform bacteria in surface waters indicates any one or combination of three sources: wastes of man, farm animals, or soil erosion, hammer [8] tc and fc counts were more than the permissible levels in most months for all stations, so it is concluded there is a tendency of increasing bacterial counts in the river through baghdad city, this increase is due to the effect of wastewater disposal to the river or the river water carried extra counts of bacteria with turbidity by the effect of runoff and intermittent rainfall occurring up stream. fig. 2: annual average of total coliform bacteria versus distance at baghdad city for year 2004. fig. 3: annual average of fecal coliform bacteria versus distance at baghdad city for year 2004. treated water quality the analysis of treated water quality characterized supplied by seven water treatment plants are summarized in (table 2 to table 8), most of these characteristic were within iraqi standards and who guidelines, the results are briefly described below: physical properties of treated water the treated water color was 5cu for all stations. the treated water has a temperature ranged from 12c to 32c with an average 22c.temperature test dose not carry any significance because there is no treatment which can be imparted to control the temperature in any water supply project. the most desirable temperature for water supply is between 10c to 15c. temperatures above 25c are undesirable, gurcharan & jagdish[8] the average monthly turbidity for treated water in baghdad was less than 5ntu, except for rwtp; the average turbidity level in rwtp was 20ntu. the turbidity of supply water is mostly used as a measure of water quality in water treatment plants, the desirable level less or equal to 1ntu was recommended by who and up to 5ntu will indicate inadequate efficiency of treatment plant and possibly correlate with increased total coliform bacteria, mccay and olson [9] inorganic chemical the monthly analysis of inorganic chemicals in treated water show that all the analyzed parameters were within permissible limits except sulfate. the average monthly of sulfate concentration of produced water was greater than the favourable level of 200mg/l (iraqi standard) in krwtp (206.5mg/l), wwtp (209mg/l), qwtp (226.5mg/l), dwtp (228.5mg/l) and rwtp (200.5mg/l),(table 2 to table 8). the majority of sulfates are soluble in water, aluminium sulfate, which is extensively used as flocculant's for water treatment may add 20-50 mg used as sulfate per litre to the final water, since sulfate is not removed from water by conventional water treatment method. high sulfate concentration in water may contribute to the corrosion of metals in the distribution system, particularly in water having low alkalinity, hammer [10] the increasing level of sulfate, hardness, and total dissolved solid in treated water could be related to the absence of any chemical treatment units in baghdad water treatment works and increasing the concentration of these variables in river water. ijcpe vol.9 no.3 (september 2008) bacterial analysis bacterial counts of all station for both tc and fc when compared with the drinking permissible levels were indicated that tc and fc bacteria counts at all station were below the permissible levels except in dwtp and rwtp (table 2 to table 8). the selection of adequate raw water intake location has been regarded as a major or almost essential "first line of defence" against the transmission of water-born diseases, twort [11], rwtp has the highest tc and fc counts are due to direct effect of wastewater discharged from untreated karada sewage 500m upstream the rwtp intake. table 2 max., min. and average monthly raw and treated water quality parameters for al-karkh (kwtp) water treatment plant (2004) constituent raw water treated water min. max. ave. min. max. ave. physical properties color <5 <5 <5 <5 <5 <5 temperature 17 27 22 16 27 21.5 turbidity 47.5 345 196.25 0.9 5.1 3.0 inorganic chemical ts 266 380 323 264 393 328.5 tss 45 260 152.5 17 26 21.5 tds 251.52 378.88 315.2 241.92 360.96 301.44 t.h 216 562 389 216 273 244.5 alkalinity 118 144 131 116 142 129 ph 7.7 7.9 7.8 7.4 7.6 7.5 ca 52 60 58 52 60 56 mg 20 29 24.5 20 29 24.5 cl 26 47 36.5 25 48 36.5 so4 69 140 104.5 70 140 105 no3+no2 al 0.01 0.01 0.01 0.09 0.15 0.12 fe 0.49 3.68 2.085 0.02 0.06 0.04 f 0.09 0.14 0.115 0.09 0.14 0.115 bacterial analysis tc 100 300 200 fc 80 130 105 table 3 max., min. and average monthly raw and treated water quality parameters for east of dijlah (ewtp) water treatment plant (2004) constituent raw water treated water min. max. ave. min. max. ave. physical properties color <5 <5 <5 <5 <5 <5 temperature 13 28 12 28 20 turbidity 118 28 73 1.0 3.0 2.0 inorganic chemical ts 270 487 378.5 290 475 282.5 tss 42 261 151.5 16 26 21 tds 332.8 570.3 451.5 326.4 556.2 441.3 t.h 232 710 471 234 296 265 alkalinity 139 147 143 130 141 135.5 ph 7.8 8.1 7.95 7.4 7.7 7.55 ca 60 75 67.5 58 72 65 mg 20 30 25 20 29 24.5 cl 42 75 58.5 39 69 54 so4 139 210 174.5 129 194 161.5 no3+no2 0.223 0.526 0.375 0.12 0.44 0.28 al 0.01 0.02 0.015 0.08 0.17 0.12 fe 0.7 1.9 1.3 0.03 0.07 0.05 f 0.1 0.22 0.16 0.07 0.10 0.08 bacterial analysis tc 1700 3000 2350 fc 1400 300 850 removal of asasbn sdfs fs f sf sdfsdfsdf fsdfsdfsdfs fsdfsdfsd 6 ijcpe vol.9 no.3 (september 2008) table 4 max., min. and average monthly raw and treated water quality parameters for al-karama (krwtp) water treatment plant (2004) constituent raw water treated water min. max. ave. min. max. ave. physical properties color <5 <5 <5 <5 <5 <5 temperature 11 30 20.5 12 30 21 turbidity 26.5 109 67.75 2.4 5.9 4.15 inorganic chemical ts 304 538 421 328 536 432 tss 61 203 132 18 29 23.5 tds 416.64 641.92 529.28 413.4 4 632.32 522.88 t.h 268 895 581.5 258 373 315.5 alkalinity 127 158 142.5 125 156 140.5 ph 7.0 8.1 7.55 7.5 7.9 7.7 ca 64 103 83.5 62 101 81.5 mg 20 33 26.5 20 32 26 cl 55 86 70.5 54 86 70 so4 157 260 208.5 155 258 206.5 no3+no2 0.822 1.16 0.991 1.1 1.49 1.295 al 0.01 0.13 0.07 0.06 0.18 0.12 fe 0.21 3.7 1.96 0.01 0.45 0.23 f 0.14 0.25 0.195 0.08 0.19 0.135 bacterial analysis tc 1000 13000 7000 fc 800 11000 5900 table 5 max., min. and average monthly raw and treated water quality parameters for al-wathba (wwtp) water treatment plant (2004) constituent raw water treated water min. max. ave. min. max. ave. physical properties color <5 <5 <5 <5 <5 <5 temperature 12 30 21 12 30 21 turbidity 20 118 69 1.0 2.7 1.85 inorganic chemical ts 371 537 454 376 539 457.5 tss 44 392 218 18 33 25.5 tds 372.48 572.16 472.32 376.5 574.5 475.84 t.h 252 871 561.5 255 396 325.5 alkalinity 131 170 150.5 123 163 143.0 ph 7.7 8.1 7.9 7.1 7.8 7.45 ca 67 111 89 67 111 89 mg 22 35 28.5 22 35 28.5 cl 44 83 63.5 45 84 64.5 so4 155 275 215 142 276 209 no3+no2 0.44 3.7 2.07 0.45 3.4 1. 925 al 0.01 0.10 0.01 0.04 0.17 0.105 fe 0.02 3.8 1.91 0.01 0.10 0.055 f 0.09 0.24 0.165 0.08 0.11 0.095 bacterial analysis tc 1000 13000 7000 fc 800 11000 5900 ijcpe vol.9 no.3 (september 2008) table 6 max., min. and average monthly raw and treated water quality parameters for al-qadisiya (qwtp) water treatment plant (2004) constituent raw water treated water min. max. ave. min. max. ave. physical properties color <5 <5 <5 <5 <5 <5 temperature 13 30 21.5 13 31 22 turbidity 39 161 94 1.7 3.55 2.62 inorganic chemical ts 391 635 513 401 637 519 tss 49 360 204.5 15 31 23 tds 386.56 663.04 524.8 401.9 664.96 533.44 t.h 259 873 566 267 387 327 alkalinity 132 167 149.5 124 161 142.5 ph 7.9 8.1 8 7.5 7.8 7.65 ca 64 109 86.5 67 109 88 mg 26 33 29.5 25 33 29 cl 47 93 70 49 93 71 so4 141 309 225 146 307 226.5 no3+no2 0.562 0.187 0.375 0.541 0.612 0.577 al 0.01 0.03 0.02 0.08 0.20 0.14 fe 0.34 2.9 1.62 0.04 0.15 0.09 f 0.08 0.16 0.12 0.08 0.16 0.12 bacterial analysis tc 2300 22000 12150 fc 1500 16000 8750 table 7 max., min. and average monthly raw and treated water quality parameters for al-doura (dwtp) water treatment plant (2004) constituent raw water treated water min. max. ave. min. max. ave. physical properties color <5 <5 <5 <5 <5 <5 temperature 11 29 20 12 27 19.5 turbidity 43 293 168 0.8 2.0 1.4 inorganic chemical ts 407 587 497 412 585 498.5 tss 47 384 215.5 15 28 21.5 tds 368.64 638.08 503.36 360.32 638.72 499.52 t.h 262 869 565.5 263 391 327 alkalinity 134 168 151 125 160 142.5 ph 7.5 8.2 7.85 7.2 7.7 7.45 ca 66 113 89.5 67 113 90 mg 24 32 28 23 36 29.5 cl 51 88 69.5 51 88 69.5 so4 168 292 230 170 287 228.5 no3+no2 0.443 0.447 0.445 0.001 0.691 0.345 al 0.01 0.03 0.02 0.08 0.2 0.14 fe 0.15 3.4 1.77 0.01 0.54 0.275 f 0.08 0.15 0.11 0.08 0.13 0.10 bacterial analysis tc 10000 95000 52500 fc 9000 80000 44500 removal of asasbn sdfs fs f sf sdfsdfsdf fsdfsdfsdfs fsdfsdfsd 8 ijcpe vol.9 no.3 (september 2008) table 8 max., min. and average monthly raw and treated water quality parameters for al-rasheed (rwtp) water treatment plant (2004) constituent raw water treated water min. max. ave. min. max. ave. physical properties color <5 <5 <5 <5 <5 <5 temperature 14 32 23 14 32 23 turbidity 34 250 142 4 36 206+ inorganic chemical ts 365 558 461.5 400 560 480 tss 51 540 295.5 18 31 24.5 tds 380.16 629.76 504.96 390.4 645.12 517.76 t.h 250 965 607.5 265 384 324.5 alkalinity 137 162 149.5 129 155 142.0 ph 7.6 8.2 7.9 7.4 7.8 7.6 ca 62 105 83.5 63 109 86 mg 24 33 28.5 23 34 28.5 cl 44 88 66 46 89 67.5 so4 148 258 203 132 269 200.5 no3+no2 0.7 0.7 0.7 0.001 1.0 0.5 al 0.01 0.01 0.01 0.01 0.24 0.17 fe 0.1 6.0 3.05 0.01 0.54 0.032 f 0.11 0.26 0.18 0.06 0.21 0.135 bacterial analysis tc 2000 130000 66000 fc 2000 110000 56000 evaluation of water treatment plant efficiency the quality of treated water is generally associated with the efficiency of water treatment plants when treated water contains salts or turbidity or organisms, more than recommended level this may inadequate treatment. the results of study showed that all water treatment plants has little effect on most of the water constituents. tds is a measure of all solids impurities other than suspended this including salts of ca, mg, so4, cl, co3, hco3, the percent removal of tds in all water treatment plants were less than 4% except in wwtp and qwtp the percent removal of tds less than zero(in minus). the percent removal of hardness was ranged between (37.1-47.2) and alkalinity was ranged between (1.4_5.6) and the percentage removal of so4 was ranged between (0.95-7.45) and less than zero in kwtp and qwtp and dwtp, while the percentage removal of cl was ranged between (0.7-7.69) and zero in kwtp and dwtp while less than zero in wwtp and qwtp and rwtp (table 9). total dissolved solids is homogeneously dispersed in the liquid, dissolved solids can be simple atoms (as small as 0.2 μm) or complex molecular compounds up to about 1mm in size, dissolved solids are present in the a liquid in one phase and cannot be removed from the water without accomplishing a phase change such as distillation, precipitation, adsorption, or extraction, mackenzie & david [9] although the percentage monthly of no3, al, f, fe concentration were low in raw water and treated water but the percent removal of these parameters were not high except iron (table 9). it is obvious that all water treatment plants were not efficient in removing pollutant especially inorganic chemical from raw water for many reasons: 1. the deficit in performance of water treatment plants depend on other factors in additional to source quality like design criteria, management of treated works, quantities of treated water, plant operations, and schedule maintains work. 2. the load on the water treatment plants was reduced their efficiency, the population of baghdad increase so must water production increased but capacity of water treatment plants remains the same. 3. conventional method for treated raw water was not enough to remove all inorganic chemicals; water treatment plants has needed to additional unit (chemical treatment unit) in order to remove those parameters. 4. tigris river water tends to be less quality as it flows to south of city, where it is highly polluted. ijcpe vol.9 no.3 (september 2008) table 9 evaluation of water treatment plants efficiency constituent percent removal alkarkh east dijlah al-karama alwathba alqadisi ya aldoura alrasheed turbidity 98.47 97.26 97.32 93.87 97.21 99.17 85.92 ts -1.702 25.363 -2.612 -0.770 -1.169 -0.30 -4.008 tss 85.573 86.138 82.196 88.3 88.753 90.023 91.70 tds 4.365 2.267 1.209 -0.745 -1.646 0.763 -2.535 t.h 37.146 47.211 45.74 42.06 42.226 42.175 46.584 alkalinity 1.526 3.244 1.4 4.983 4.68 5.6 5.0 ca 3.448 3.704 2.395 zero 1.734 -0.558 -2.99 mg zero zero 1.886 zero 1.69 -5.357 zero cl zero 7.692 0.7 -1.574 1.428 zero -2.27 so4 -0.40 7.449 0.95 2.790 -0.66 0.652 1.2 no3 0.253 0.402 7.0 -0.53 22.47 28.97 al -51.16 -7.0 -0.71*100 -9.5 -6*100 -6*100 -16*100 fe 98 96.15 88.23 95.02 94.44 98.8 98.9 f zero 50 30.76 42.42 zero 10.0 25.0 statistical analysis in this study the statistical analysis which carried out was the correlation and regression analysis, they are commonly used to interpret the relationships between two or more variables and to develop statistical models. the relationship that exits between turbidity (dependent variable) associated with a given value of the (independent variable) total coliform bacteria for raw water at intake of all water treatment plants. regression and correlation analysis for these data were conducted several models were analyzed using computer software (excel, spss) to obtain best coefficient of correlations. the exponential model used for single regression analysis was: exponential model c x ebay * where: y: dependent variable. x: independent variable. a, b, c: regression coefficients the correlation coefficients between turbidity and total coliform bacteria in river water for kwtp, ewtp and krwtp were good 0.73, 0.76 and 0.76 respectively but the results reflected high correlation coefficient for other water treatment plants (table 10 and fig. 5 to fig. 11), because the source of bacteria at north of baghdad was probably the intermittent rainfall and storm water runoff, surface water generally contain suspended and colloidal solids from land erosion, decaying vegetation, and microorganisms, hammer [8]. however the additional bacteria at other water treatment plants were affected by the bacteriological pollutants, which increased by waste water discharged directly to the river or by storm networks systems, which are combined illegally to the sewerage systems or by the overflow from some sewerage pump stations. table 10 the coefficients of the regression function and the correlation coefficients for all water treatment plants. tation r 2 adj. r 2 a b c equation kwtp 0.73 0.54 81.47 1.55x10 -4 20.95 exponential ewtp 0.76 0.40 43.38 3.42x10 -10 53.69 exponential krwtp 0.76 0.40 47.15 7.93x10 -5 829.64 exponential wwtp 0.92 0.81 30.17 0.48 2507.78 exponential qwtp 0.95 0.87 47.06 86x10 -5 1996.78 exponential dwtp 0.98 0.97 50.14 2.19x10 -5 5855.37 exponential rwtp 0.95 0.93 8.92 31.75 62647.13 exponential fig. 5: coefficients of the regression function and correlation coefficients for kwtp . exponential equation (a,b,c) r^2=0.73744591 df adj r^2=0.54053034 fitstderr=62.177713 fstat=7.0218474 a=81.47382 b=0.00015547951 c=-20.952004 100 150 200 250 300 total caliform bacteria npn/100ml 0 50 100 150 200 250 300 350 t u rb id it y n t u 0 50 100 150 200 250 300 350 t u rb id it y n t u removal of asasbn sdfs fs f sf sdfsdfsdf fsdfsdfsdfs fsdfsdfsd 10 ijcpe vol.9 no.3 (september 2008) fig. 7: coefficients of the regression function and correlation coefficients for krwtp fig. 8: coefficients of the regression function and correlation coefficients for wwtp fig. 9 coefficients of the regression function and correlation coefficients for qwtp fig. 10: coefficients of the regression function and correlation coefficients for dwtp. . exponential equation (a,b,c) r^2=0.76072419 df adj r^2=0.40181048 fitstderr=13.395059 fstat=4.7689163 a=47.156038 b=7.9311707e-05 c=-829.64822 3000 5000 7000 9000 11000 total coliform bacteria npn/100ml 30 40 50 60 70 80 90 100 t u rb id it y n t u 30 40 50 60 70 80 90 100 t u rb id it y n t u . exponential equation (a,b,c) r^2=0.92528026 df adj r^2=0.81320064 fitstderr=12.582378 fstat=18.575016 a=30.17789 b=0.4868841 c=-2507.7808 0 5000 10000 15000 total coliform bacteria npn/100ml 20 30 40 50 60 70 80 90 100 110 120 t u rb id it y n t u 20 30 40 50 60 70 80 90 100 110 120 t u rb id it y n t u exponential equation (a,b,c) r^2=0.95091966 df adj r^2=0.87729914 fitstderr=13.575717 fstat=29.062134 a=47.065819 b=0.0018676847 c=-1996.7875 0 5000 10000 15000 20000 25000 total caliform bacteria npn/100ml 25 50 75 100 125 150 175 t u rb id it y n t u 25 50 75 100 125 150 175 t u rb id it y n t u exponential equation (a,b,c) r^2=0.98673107 df adj r^2=0.97876972 fitstderr=10.82648 fstat=223.09213 a=50.140818 b=2.1933694e-05 c=-5855.3767 10000 30000 50000 70000 90000 total caliform bacteria npn/100ml 0 50 100 150 200 250 300 t u r b id it y n t u 0 50 100 150 200 250 300 t u r b id it y n t u ijcpe vol.9 no.3 (september 2008) fig. 11: coefficients of the regression function and correlation coefficients for rwtp. conclusions 1. results indicated that sulfate is the major problem of baghdad water treatment works south of tharthar canal, the average level of sulfate concentration of produced water for all water treatment plants than the favourable level of 200 mg/l. 2. inorganic chemicals under study are not affected by the treatment process and the concentration are the same in both river water and drinking water for alkalinity, calcium, magnesium, and chloride, but few increases in the concentration of total dissolved solids, total hardness, and sulfate, in treated water due to the addition of alum to the water during the coagulation process, and to the absence of any chemical treatment units in baghdad water treatment works. 3. water characteristics at rwtp exceeded the water quality standards which recommended by who particularly bacterial counts and turbidity, because rwtp with draws raw water of higher bacteria counts as compared with other water treatment plants. 4. the source of bacterial counts at station (north of baghdad) was probably to intermittent rainfall and storm water runoff as well as other sources, however the additional bacteria at rwtp can be considered due to wastewater disposed from pollution sources upstream this station. 5. the correlation coefficient between turbidity and total coliform bacteria in river water were good at kwtp, ewtp and krwtp while the correlation coefficient began to increase at other water treatment plants due to waste water disposed from pollution sources upstream this stations. reference 1. abu hamdeh, m. r. m., 2000, "study of tigris water quality and treated water at the water treatment plant for baghdad city", m.sc. thesis, college of engineering, university of baghdad. 2. al-masri,n.a.,1986,"quality of tigris river water at baghdad and suitability for drinking purposes" proceeding of fourth scientific conference, biological sciences, scientific conference, baghdad, vol.5,part 2,pp.375-391. 3. directorate general of human environment, 1988. "the new limits of the regulation of river and public waters from the pollution no.25 for year 1967", ministry of health environ. laws”, pp.2937. 4. evison,l.m.,1988,"comparative studies on the survival of indicator organisms and pathogens in fresh sea water"water science technology, vol.20,no.12,pp305-315 5. federal water pollution control administration, 1972, "water quality criteria", report of the national technical advisory committee to the secretary of the interior. 6. gurcharan s. & jadish s.1994, "water supply and sanitary engineering" standard publishers distributors. 7. lechevallier, m.w.&t.m. evans & r.j. seidler, 1981, "effect of turbidity on chlorination efficiency" ,environmental microbiology,vol.42,no.1. 8. hammer, m.j., 1977, "water and wastewater technology" by john wily & sons, inc exponential equation (a,b,c) r^2=0.94911095 df adj r^2=0.93002755 fitstderr=19.659903 fstat=83.927661 a=8.9291132 b=31.756262 c=-62647.134 0 50000 1e+05 1.5e+05 total caliform bacteria npn/100ml 0 50 100 150 200 250 t u rb id it y n t u 0 50 100 150 200 250 t u rb id it y n t u removal of asasbn sdfs fs f sf sdfsdfsdf fsdfsdfsdfs fsdfsdfsd 12 ijcpe vol.9 no.3 (september 2008) 9. mackenzie l. davis & david a.cornwell,1991, "introduction to environmental engineering", 2nd edition, mcgraw-hill series in water resources and environmental engineering. 10. mccay w.f & b.h.olson, 1986. "relationship among turbidity, particle counts and bacteriological quality within water distribution lines." water research, vol. 20, no.8, pp.10231029 11. mutlak, s. m., 1980, "microbiological, physical and chemical characteristic of tigris river", technical bulletin, no. 10, scientific research foundation – baghdad. 12. nawar, o. a. n., 2001, "variation of salinity indication parameters of tigris river in baghdad city (1990-1999)", m.sc. thesis, college of engineering, university of baghdad. 13. table curve 2d v5.0, 2000, aisn software, usa. 14. twort, a.c., f.m. law & f.w. crowley, 1985, "water supply", edward arnold ltd., london. 15. world health organization,1984,"guidelines for drinking water quality-health criteria and other supporting information" vol.2. iraqi journal of chemical and petroleum engineering vol.15 no.2 (june 2014) 3948 issn: 1997-4884 viscosity reduction of sharqi baghdad heavy crude oil using different polar hydrocarbons, oxygenated solvents hussein qasim hussein and saja abdul-wahhab mohammad chemical engineering department, college of engineering, university of baghdad abstract this work studied the facilitation of the transportation of sharqi baghdad heavy crude oil characterized with high viscosity 51.6 cst at 40 °c, low api 18.8, and high asphaltenes content 7.1 wt.%, by reducing its viscosity from break down asphaltene agglomerates using different types of hydrocarbon and oxygenated polar solvents such as toluene, methanol, mix xylenes, and reformate. the best results are obtained by using methanol because it owns a high efficiency to reduce viscosity of crude oil to 21.1 cst at 40 °c. toluene, xylenes and reformate decreased viscosity to 25.3, 27.5 and 28,4 cst at 40 °c, respectively. asphaltenes content decreased to 4.2 wt. % by using toluene at 110 °c. and best improvement in api of the heavy crude oil is 26.1 at 40 °c by using xylenes. keywords: heavy crude oil; transportation; asphaltene content; viscosity reduction introduction petroleum transportation has become a complex and highly technical operation. one of the major difficulties in the pipeline transportation is the high viscous fluids that require efficient and economical ways to transfer the heavy crude. heavy crude oils have a density approaching or even exceeding that of water. they are usually extremely viscous, with a consistency ranging from that of heavy molasses to solid at room temperature. heavy crude oils are not pumped easily through the pipelines because of the high concentrations of sulfur and several metals, particularly nickel and vanadium. crude oils are complex fluids that can cause a variety of difficulties during the production, separation, transportation and refining of oil [1, 2]. heavy crude is high viscosity ,and high specific gravity as well as heavy molecular composition. it is dense and viscous due to the high presence of naphthenes and paraffines [3]. heavy crude oil contains greater proportions of higher-boiling constituents such as (lubricating oil motor oils, lubricants, engine oil, cylindrical oil, and gear oil),greases and wax, and residue (residual fuel oils, coke, tar and asphalt).in addition, more aromatic, and heteroatom containing (n, o, s and metals) are contained in heavy petroleum than light petroleum [4]. such asphalting is considered as a ruthless problem within the petroleum industry due to their various costy problems in terms of production loss iraqi journal of chemical and petroleum engineering university of baghdad college of engineering viscosity reduction of sharqi baghdad heavy crude oil using different polar hydrocarbons, oxygenated solvents 40 ijcpe vol.15 no.2 (june 2014) -available online at: www.iasj.net and transport difficulties. heavy crudes account for a large fraction of the world’s potentially recoverable oil reserves. the viscosities of those crudes at room temperature vary from 100mpas to more than 10 5 mpas. generally, crude oil with viscosity <400 mpas is the classical maximum desired pipeline viscosity [5-7]. the high viscosity of heavy oil is a crucial factor that strongly affects its up-stream recovering, down-stream surface transporting and refining processes. a better understanding of the origination of its high viscosity can greatly help to find more effective and economical methods for recovering the heavy oil and reducing the related capital and/or operating costs [8]. therefore, different methods are used in order to reduce the viscosity of the heavy crude for the pipeline transportation. for instance, upgrading, dilution with lighter crudes or alcohols, heating, and the use of surfactants to stabilize emulsions are some of those common methods, oxidation and drag reduction. heating is a common method utilized to overcome the above noted problems of transporting heavy oil by pipeline [1]. another way to transport heavy oil is to heat the oil as the viscosity decreases very rapidly with increasing temperature. the basis for this method lies in the fact that as heavy oil is heated, the viscosity of the heavy oil is reduced and thus made easier to pump. therefore, it is important to heat the oil to a point where the oil has a substantially reduced viscosity. a principle drawback to the use of heated pipelines is the high capital and operational cost of such a heated pipeline over long distances [5]. in addition, underwater pipeline transportation of heavy oil through a heated pipeline is very difficult due to the cooling effect of the surrounding water and the practical difficulty of maintaining pumping stations and heating stations [9, 10]. several experimental studies have shown that heavy oil viscosity is strongly dependent on the volume fraction, chemical structures, and physicochemical properties of its asphaltenes, which are the most polar and/or heaviest components in heavy oil [11, 12]. petroleum asphaltenes are defined as a solubility class of the heavy components in crude oil which are insoluble in nonpolar solvents. asphaltenes exist in the form of colloidal dispersions stabilized by other constituents of the crude oil. these naturally occurring dispersions can be easily disturbed by a variety of mechanical and physicochemical conditions involved in oil field recovery and production. changes in temperature and pressure, commingling of crude and condensate streams, and especially the use of enhanced recovery techniques can result in asphaltene destabilization, precipitation, and eventual deposition. once deposited, asphaltenes pose a multitude of problems for crude oil producers [13]. studies have shown that asphaltenes exhibit properties similar to colloids. these colloids exist in the heavy oil matrix in a micelle form. since the mole fraction of resins is higher than asphaltenes in petroleum, micelles are richer in resins. asphaltenes also exhibit properties of colloidal systems such as the ‘critical micelle concentration’ (cmc) at which aggregates begin to form. the breaking down of asphaltenes upon the addition of polar solvents can be rationalized in terms of a reduction in the solubility parameter or the polarity of the hydrocarbon medium [14-16]. the formation of micelles is believed to be primarily due to the interaction between asphaltene species or hussein qasim hussein and saja abdul-wahhab mohammad -available online at: www.iasj.net ijcpe vol.15 no.2 (june 2014) 41 asphaltene-resin fractions. the nature of the intermolecular or intramolecular forces that cause the formation of asphaltene micelles is not clear at present. it has been suggested that a number of forces may be involved including van der waals attraction, dipole-dipole interaction, hydrogen bonding, electron-transfer or charge transfer between aromatics (𝜋-𝜋 bonding), and porphyrin interaction [17-18]. the aim of the present work is to study the reduction viscosity of heavy crude oil using different polar hydrocarbons and oxygenated solvents (toluene, methanol, mix xylenes and reformate) at different concentration (4, 8, 10 and 12 wt.%) and different temperature (40 °c and boiling point for each solvents except reformate at 100 °c) on the efficiency of viscosity reduction systems. experimental feedstock the feedstock in this study was sharqi baghdad crude oil, obtained from baghdad east oil fields. the properties of the crude are given in table 1. table 1: physical properties of sharqi baghdad crude oils test crude oil from east of baghdad viscosity at 40°c 51.6 (cst) api at 60°f 18.8 asphaltene content 7.1 wt.% sulfur content 5.0 wt.% vanadium 88 ppm iron 25 ppm nickel 38 ppm saturate compounds 42.2 ppm naphthene compounds 23.8 wt.% light naphtha light naphtha was supplied from aldoura refinery, with viscosity and density 6.76*10 7 (stock) and 0.65 g cm -3 , respectively. reformate reformate was supplied from aldoura refinery, with boiling point 225 °c. toluene solvent (c7h8) toluene was supplied from (gcc.gainland chemical company). with molecular weight, boiling point and density are (92.14 kg/mole, 110 °c and 0.87 g/cm 3 ), respectively. methanol solvent (ch3oh) methanol was supplied from (poch sa) company. with molecular weight, density and boiling point are 32.04, 0.79 g cm -3 and 65 °c, respectively. xylenes mixture (c8h10) xylenes mixture of isomers, extra pure, is supplied from al-doura refinery. with molecular weight, density and boiling point are 106.17, 0.68 g cm -3 and 137.76 °c, respectively. distillation stage two liters of sharqy baghdad heavy crude oil were subjected to the distillation using computerized laboratory apparatuse (according astm 5236) (pignat company, france) that consists of distillation flask, heating mantle, distillation column, condenser, thermometer and fraction collector as shown in fig. 1. distillation was carried out to remove naphtha from crude oil to obtain stripped crude oil; the initial boiling point was 75 °c to the end point of distillation was 175 °c. distillated naphtha was represented 17% vol. based on crude oil. viscosity reduction of sharqi baghdad heavy crude oil using different polar hydrocarbons, oxygenated solvents 42 ijcpe vol.15 no.2 (june 2014) -available online at: www.iasj.net fig. 1: schematic diagram of the labrorty distillation unit solvent stage 1. mixing a 250 ml two-necked flat bottom flask was equipped with high efficiency condenser from one neck and with the sensor of controlled hot plate magnetic stirrer (stuart) from another. a chiller (gallenham) was used for providing cold water for condenser as shown in fig. 2. a 100 g of stripped crude oil was poured into the mixing flask for each run. mixing was carried out with two temperatures, 40 °c and normal boiling point of each solvent with various solvent concentrations 4,8,10 and 12 wt.% based on crude oil. the sample of stripped crude oil was heated to the temperature of treatment and then a specific concentration of solvent was added; the duration of mixing was 1h. fig. 2: schematic diagram of the mixing unit 2. evaporation treated stripped crude oil was exposed to the evaporation to ensure a recovering not less than 90% of solvent from treated samples of stripped crude oil with solvent. temperature of evaporation was varied according to the boiling point of each solvent. 3. blending the evaporated sample of treated stripped crude oil was blended with distilled naphtha recovered from distillation stage. constant blending percentage (vol. 17%) of naphtha was blended to ensure converting evaporated treated stripped crude oil to treated crude oil. results and discussions the results obtained in the present investigation for viscosity reduction of sharqi baghdad heavy crude oil by the breakdown of asphaltenes using different polar solvents at different temperatures and concentrations are as follows: hussein qasim hussein and saja abdul-wahhab mohammad -available online at: www.iasj.net ijcpe vol.15 no.2 (june 2014) 43 effect of solvent type on asphaltene content figures 3, 4, 5 and 6 show the effect of different types of polar solvents with different concentration on the asphaltene content. the feedstock is exposed to different solvents at different concentrations and temperatures. these solvents reduced asphaltenes content affected by temperature and the action of polar solvents to disperse asphaltene agglomerates. from figures 3, 4, 5 and 6, the higher reduction in asphaltene content is obtained with toluene 4.3638 wt.% at 40°c, while 5.0071 wt.% asphaltenes is obtained with reformate, 5.0381 wt.%, and 5.0392 wt.% asphaltene content is obtained with xylenes and methanol, respectively. it is well known that special types of compounds have the ability to break down aspaltene agglomerates. the presence x of electrons in the ring of solvents may play a role in the interaction between the compounds added and the n electrons in the polyaromatic systems of the asphaltene agglomerates. the compounds kept to one ring to keep the size of the molecules allow for a greater diffusion through the crude oil matrix and penetration into the asphaltene agglomerates. fig. 3: effect of toluene weight fraction on asphaltene content of crude oil fig. 4: effect of xylene weight fraction on asphaltene content of crude oil fig. 5: effect of methanol weight fraction on asphaltene content of crude oil fig. 6: effect of reformate weight fraction on asaphaltene content of crude oil solvent wt.% a s p h a lt e n e c o n t e n t 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 3 5 7 9 11 13 asphaltene at 40 o c asphaltene at 110 o c solvent wt.% a s p h a lt e n e c o n t e n t 5.0 5.2 5.4 5.6 5.8 6.0 6.2 6.4 6.6 3 5 7 9 11 13 asphaltene at 40 o c asphaltene at 138 o c solvent wt.% a s p h a lt e n e c o n t e n t 4.8 5.0 5.2 5.4 5.6 5.8 6.0 6.2 6.4 6.6 3 5 7 9 11 13 asphaltene at 40 o c asphaltene at 65 o c solvent wt.% a s p h a lt e n e c o n t e n t 4.8 5.2 5.6 6.0 6.4 6.8 3 5 7 9 11 13 asphaltene at 40 o c asphaltene at 100 o c viscosity reduction of sharqi baghdad heavy crude oil using different polar hydrocarbons, oxygenated solvents 44 ijcpe vol.15 no.2 (june 2014) -available online at: www.iasj.net effect of solvent type on viscosity the effect of solvent concentration at different temperature on viscosity reduction of sharqi baghdad heavy crude oil was studied. figures 7, 9, 11 and 13 show the effect of different concentrations of toluene, methanol, xylenes, and reformate on viscosity of crude oil at different temperatures, respectively. the viscosity decreased with increasing solvent concentration. the heavy crude oil viscosity decreases maximally from 51.6 cst to 21.7 cst at 110 °c by using toluene, and to 21.1, 27.5, and 28.4 cst at 40 °c by using methanol, xylenes, and reformate, respectively. it is widely assumed that the asphaltene molecules in oil agglomerate to form micelle-like cluster. interactions between these clusters contribute towards the viscosity of the oil. by breaking these agglomerates apart, viscosity will be reduced. so, increasing polar solvent concentration had an essential role on increasing and acceleration of breaking down the asphaltene agglomerates, and thus achieved deeper viscosity reduction [19]. the addition of a polar solvent acted on the colloidal structure of the asphaltenes and the viscosity decreased. the higher the polarity parameter or the hydrogen bonding parameter of the solvent was, the greater the viscosity reduction was [20]. to access the extent of the viscosity reduction, the percentage of viscosity reduction vr % was introduced and it was calculated by eq. 1[21]. ( ) …(1) where and are the reference and corresponding viscosities of crude oil in cst at 40°c. figures 8, 10, 12, and 14 show the viscosity reduction percentage vs. solvent concetration at different temperatures for different solvents. figs. 7 and 8 show that toluene gave best viscosity reduction at 110 °c; toluene is a strong solvent that owns a high ability to disperse the asphaltene agglomerates. fig. 7: effect of toluene weight fraction on viscosity of crude oil fig. 8: effect of toluene weight fraction on viscosity reduction percentage of crude oil if partial solubility or phase separation is occurring such as methanol, then a lower than expected viscosity measurement will be recorded. this is because when phase separation occurs, then the more fluid phase, the additive compound, may tend to concentrate around the spindle of the viscometer, and thus lower apparent viscosity [22]. solvent wt.% v is c o s it y ( c s t ) 21.5 22.5 23.5 24.5 25.5 26.5 27.5 3 5 7 9 11 13 viscosity at 40 o c viscosity at 110 o c solvent wt.% v is c o s it y r e d u c t io n % 48 50 52 54 56 58 60 3 5 7 9 11 13 viscosity at 40 o c viscosity at 110 o c hussein qasim hussein and saja abdul-wahhab mohammad -available online at: www.iasj.net ijcpe vol.15 no.2 (june 2014) 45 methanol owns high polarity more than the other solvent used in this study. so the lowest crude oil viscosity was achieved by this solvent. the effect of methanol concentration on viscosity is better at low temperature 40 °c than at its boiling point or high temperature, and this is more economical point of work as shown in figure 9. figure 10 clarify vr% of methanol. fig. 9: effect of methanol weight fraction on viscosity of crude oil fig. 10: effect of methanol weight fraction on viscosity reduction percentage of crude oil xylenes mixture gives good results on reducing the viscosity of heavy crude oil. pure isomers of xylenes are more efficient at low temperature, 40 °c, than high temperature, 138 °c, as shown in figure 11; figure 12 clarifies vr%. figure 13 shows the effect of using reformate to reduce viscosity in crude oil at different concetrations and different temperature; viscosity of the crude at 40 °c is better than 100 °c. figure 14 clarifies vr% of reformate . fig. 11: effect of xylenes weight fraction on viscosity of crude oil fig. 12: effect of xylenes weight fraction on viscosity reduction percentage of crude oil fig. 13: effect of reformate weight fraction on viscosity of crude oil solvent wt.% v is c o s it y ( c s t ) 21 22 23 24 25 26 27 28 3 5 7 9 11 13 viscosity at 40 o c viscosity at 65 o c solvent wt.% v is c o s it y r e d u c ti o n % 46 48 50 52 54 56 58 60 62 3 5 7 9 11 13 viscosity at 40 o c viscosity at 65 o c solvent wt.% v is c o s it y ( c s t) 27.4 27.8 28.2 28.6 29.0 29.4 29.8 30.2 3 5 7 9 11 13 viscosity at 40 o c viscosity at 138 o c solvent wt.% v is c o s it y r e d u c ti o n % 42 43 44 45 46 47 3 5 7 9 11 13 viscosity at 40 o c viscosity at 138 o c solvent wt.% v is c o s it y ( c s t) 28 29 30 31 32 33 3 5 7 9 11 13 viscosity at 40 o c viscosity at 100 o c viscosity reduction of sharqi baghdad heavy crude oil using different polar hydrocarbons, oxygenated solvents 46 ijcpe vol.15 no.2 (june 2014) -available online at: www.iasj.net fig. 14: effect of reformate weight fraction on viscosity reduction percentage of crude oil api gravity the api of heavy crude oil was increased with increasing solvent concentration at different temperatures. figures 15, 16, 17 and 18 show the effect of solvents concentration on improvement of api values at difference temperatures. it is clear that the breaking down of asphaltenes agglomerates and reducing presence of micelle-like clusters had an essential role in the improvement of api for heavy crude oil, where the polar solvents played on dispersion of asphaltenes molecules, reduction of their molecular size, and decreasing of asphaltenes content, which led to the increasing of api of heavy crude oil. fig. 15: effect of toluene weight fraction on api of crude oil fig. 16: effect of methanol weight fraction on api of crude oil fig. 17: effect of xylenes weight fraction on api of crude oil fig. 18: effect of reformate weight fraction on api of crude oil solvent wt.% v is c o s it y r e d u c ti o n % 36 37 38 39 40 41 42 43 44 45 3 5 7 9 11 13 viscosity at 40 o c viscosity at 100 o c solvent wt.% a p i a t ( 6 0 / 6 0 ) o f 19 20 21 22 23 24 25 3 5 7 9 11 13 api at 40 o c api at 110 o c solvent wt.% a p i a t ( 6 0 / 6 0 ) o f 20.5 21.5 22.5 23.5 24.5 25.5 26.5 3 5 7 9 11 13 api at 40 o c api at 65 o c solvent wt.% a p i a t ( 6 0 /6 0 ) o f 22.5 23.0 23.5 24.0 24.5 25.0 25.5 26.0 26.5 27.0 3 5 7 9 11 13 api at 40 o c api at 138 o c solvent wt.% a p i a t ( 6 0 / 6 0 ) o f 22.0 22.6 23.2 23.8 24.4 25.0 3 5 7 9 11 13 api at 40 o c api at 100 o c hussein qasim hussein and saja abdul-wahhab mohammad -available online at: www.iasj.net ijcpe vol.15 no.2 (june 2014) 47 conclusion from rheological and structure measurements heavy oils can be described as aggregation of agglomeration asphaltenes particles; heavy viscosities of this type of crudes are due to the entanglement of solvated asphaltene particles. some ways that will limit the entanglement will likely reduce the viscosity. according to the results obtained from this study, the following conclusions are obtained: 1. treatment of the heavy crude oil with different polar solvents gave high reduction in viscosity and asphaltene content; methanol owned a high efficiency to reduce viscosity of crude oil to 21.109 cst at 40 °c.toluene, xylenes and reformate decreased viscosity to 25.37, 27.510 and 28.407 cst at 40 °c, respectively. 2. api of heavy crude oil improved to 26.193 at 40 °c by using xylenes, toluene, methanol and reformate improvement api to 23, 25.374 and 24.753 at 40 °c, respectively. 3. asphaltenes content decreased to 4.259 wt. % by using toluene at 110 °c. methanol, xylenes and reformate decreased asphaltene content to 5.0392, 5.0381 and 5.0071 wt. % at 40 °c, respectively. 4. crude oil viscosity decreased with decreasing asphaltenes content. 5. crude oil viscosity was decreased with increasing polar solvent concentration. references 1al-besharah jm, salman oa, akashah sa., (1987), "viscosity of crude oil blends". ind eng chem res 1987; 26:244, pp 5–9. 2speight jg., (1998),"petroleum chemistry and refining" .philadelphia: taylorand franci. 3petroleumwikipedia, the free encyclopedia. retrieved april 12, (2007), from http://en.wikipedia.org/wiki/petrole um. 4speight, j. g., (2001), "handbook of petroleum", john wiley and sons inc., canada, pp: 182. 5nunez g, briceno m, mata c, rivas h, joseph d.,(1996), "flow characteristics of concentrated emulsions of very viscous oil in water systems". j rheol 1996, 40:405-23. 6fruman dh, briant j. (1983),"investigation of the rheological characteristics of heavy crude oil-in-water emulsions". in: international conference on the physical modeling of multi-phase flow. england: coventry. 7schumacher mm. (1980),"enhanced recovery of residual and heavy oils". new jersey: park ridge, noyes press. 8peng luo, yongan gu, (2006),"effects of asphaltene content on the heavy oil viscosity at different temperatures" petroleum technology research centre (ptrc), petroleum systems engineering, faculty of engineering, university of regina, regina, saskatchewan, s4s0a2 canada, pp 1096. 9ali ma, nofal wa. (1994), "application of high performance liquid chromatography for hydrocarbon group type analysis of crude oils". fuel sci. technol. int., 12(1):21–33. 10 zaki nn, butz t, kessel d. rheology, (2001), "particle size distribution, and asphaltene deposition of viscous asphaltic crude oil-in-water emulsions for pipeline transportation". petrol sci. technol.; 19:425–35. 11khan mab, mehrotra ak, svrcek wy. (1984) ,"viscosity models for gas-free athabasca http://en.wikipedia.org/wiki/petroleum http://en.wikipedia.org/wiki/petroleum viscosity reduction of sharqi baghdad heavy crude oil using different polar hydrocarbons, oxygenated solvents 48 ijcpe vol.15 no.2 (june 2014) -available online at: www.iasj.net bitumen". j can pet technol; 23:4, pp7–53. 12puttagunta vr, miadonye a, singh b. (1993), "simple concept predicts viscosity of heavy oil and bitumen". oil gas j; 91:7 pp 1–3. 13manek m.b., nallo/exxon, (1995), "asphaltene dispersants as demulsification aids", energy chemicals l.p. , spe international symposium on oilfield chemistry, pp 14-17. 14storm, d.a.; barresi, r, j.; decanio, s.j., fuel, (1991), "colloidal nature of vacuum residue", pp 779-782. 15 speight, j.g., (1991), "the chemistry and technology of petroleum", 2 ed ., marcel dekker: new york, ny. 16 wiehe, i.a., (1992), "solventresid phase diagram for tracking resid conversion", ind. eng. chem. res., pp. 530-536. 17wiehe, i.a., (1993), "a phaseseparation kinetic model for coke formation", ind. eng. chem. res, pp 2447-2454. 18 li, s.; liu, c.; que, g.; liang, w.; zhu, y., (1997), "a study of the interactions responsible for colloidal structures in petroleum residua", fuel, pp 1459-1463. 19 mark w. badger and harold h. schobert, "viscosity reduction in extra heavy crude oils", the laboratory for hydrocarbon process chemistry the energy institute. 209 academic projects building, the pennsylvania state university, pp 461. 20p. gateau , i. hénaut , l. barré and j.f. argillier, (2004), "heavy oil dilution",vol. 59, no. 5, oil and gas science and technology – rev. ifp, pp. 503-509. 21ghannam mt, esmail n., (2006), "flow enhancement of medium-viscosity crude oil", j pet sci technol; 24(8):9, pp85-99. 22brian clark, (2007),"heavy oil, extra-heavy oil and bitumen unconventional oil", national petroleum council, working document of the npc global oil and gas study ,topic paper 22,pp 4. iraqi journal of chemical and petroleum engineering vol.17 no.3 (september 2016) 5773 issn: 1997-4884 experimental study and mathematical modelling of zinc removal by reverse osmosis membranes ahmed faiq al-alawy and miqat hasan salih chemical engineering department, college of engineering, university of baghdad abstract in this study, aromatic polyamide reverse osmosis membranes were used to remove zinc ions from electroplating wastewater. influence of different operating conditions such as time, zinc concentration and pressure on reverse osmosis process efficiency was studied. the experimental results showed, concentration of zinc in permeate increase with increases of time from 0 to 70 min, and flux of water through membrane decline with time. while, the concentrations of zinc in permeate increase with the increase in feed zinc concentration (10–300 mg/l), flux decrease with the increment of feed concentration. the raise of pressure from 1 to 4 bar, the zinc concentration decreases and the flux increase. the highest recovery percentage was found is 54.56% for reverse osmosis element, and the highest rejection of zinc was found is 99.49%. experimental results showed that the concentrations of zinc ion in permeate was lower than the permissible limits (i.e. ˂ 10 ppm). a mathematical model describing the process was investigated and solved by using matlab program. theoretical results were consistent with the experimental results approximately 90%. keywords: heavy metals, reverse osmosis, zinc ions, mathematical modelling. introduction the world's population and the consequent desire for water supply increase, conservation of the invaluable and increasingly rare resource of water and sustainable development will require recycling and reuse. then, water resource sustainability interests suggest exploring the possibility of reusing treated water as a promising source of water [1]. the development of industries such as tanneries, mining operations, paper industries, metal plating facilities, batteries, fertilizer industries, petroleum refining, photographic process industry, textile industry and pesticides etc., a considerable amount of wastewater containing heavy metals is discharged into the water, particularly in developing countries [2]. the high solubility in the aqueous environments, heavy metals can be absorbed by living organisms. they enter the food chain, high concentrations of heavy metals may accumulate in human body [3, 4]. heavy metals are elements having atomic weights between 63.5 and 200.6, and a specific gravity greater than 5.0 [5]. zinc organizes many university of baghdad college of engineering iraqi journal of chemical and petroleum engineering experimental study and mathematical modelling of zinc removal by reverse osmosis membranes www.iasj.netavailable online at: 6) 201 september( 3no. 7ijcpe vol.1 85 biochemical processes and is important for the physiological functions of living tissue. high concentrations of zinc cause prominent health problems, such as nausea, skin irritations, vomiting, anemia and stomach cramps. it is a trace element that is essential for human health [6]. the maximum contaminant level (standards) of zinc metal in water is 0.6-5 mg/l in hong kong sar for environmental protection department (epd) [7], <10 mg/l for egyptian environmental standards law (93/62)/ and decree (44/2000) [8] and 2 mg/l for the iraq regulation limits [9]. thus, heavy metals removal from discharge water becomes an increasingly important matter globally. toxic heavy metals of particular interest in industrial wastewaters treatment involve zinc, chromium, mercury, copper, nickel, cadmium and lead [10, 11]. different methods have been discussed for removing heavy metals from waters such as: coagulation, chemical precipitation, using ion exchange resins, flocculation, floatation, adsorption, electrochemical processes, and membrane methods [7, 12]. membrane separation technologies have been specified to be a promising and feasible option for removal of heavy metal due to their ease of operation and high efficiency. ultrafiltration (uf) and reverse osmosis (ro) are now being increasingly used for heavy metals removal from wastewater. nanofiltration (nf) is less investigated intensively than ro for heavy metals removal because that ro is more effective to remove the divalent ions from wastewater than nf[13]. ro was the first membrane process to be widely commercialized. ro membranes are used to separate low molecular weight compounds and salts from water because they are highly permeable to water and highly impermeable to colloids, microorganisms, organic molecules and salts [14]. ro is one of the effective technologies to remove almost all pollutants, especially those with low concentrations. ro technology is also used today in large water treatment plants. it produces good quality of potable water from seawater and brackish water resources, reduce water salinity and improve polluted water sources for industrial applications. in addition, the application of series of ro membrane elements covers household units to produce higher quality of drinking water [15]. in this study, the effect of time, feed concentration and pressure on flux and permeate concentration, and comparison between experimental and theoretical results have been studied for reverse osmosis membranes to remove zinc ions from wastewater. mathematical model spiral wound element is the most popular type of membrane element in use. water passes through the element, some water passes into the permeate channel, resulting in continuously changing conditions over the length of the element [16]. 1. steady state calculations in the solution-diffusion model, the transport of solvent and solute are independent of each other. the flux of solvent through the membrane is linearly proportional to the pressure difference across the membrane [17]: …(1) where: is the flux of water (l/m 2 .h), is the permeability coefficient of pure water (l/m 2 .h.bar), is the applied pressure driving force (bar) and is the osmotic pressure of the solution (bar). http://www.iasj.net/ ahmed faiq al-alawy and miqat hasan salih 85 )6201september ( 3no. 17ijcpe vol. www.iasj.netonline at: available solution osmotic pressure is related to its dissolved solute concentration and is predicted from van't hoff equation as: …(2) where: is the osmotic coefficient (dimensionless), i is the number of dissociated ions per molecule (van’t hoff factor) (dimensionless), t is the temperature (k), rg is the universal gas constant (l.bar/mole.k) and c is the concentration of solute (mg/l). the van't hoff factor is inserted to more than deviations from ideal solution behavior that implicates finite volume occupied by molecules of solute and their mutual attraction as in vander waals attraction [18]. the solute flux through the membrane is proportional to the solute concentration difference across the membrane [17]: …(3) where: is the solute mass flux (mg/m 2 .h), is the permeability coefficient of salt (m/h) and is the concentration gradient across membrane (mg/l). and: …(4) where: is the concentration in permeate (mg/l). by measuring the solute concentrations in feed solution ( ) and also in permeate solution ( ), the rejection is calculated from the rejection data as follows [11]: ) …(5) where: is the solute rejection (dimensionless) and is the concentration in feed solution. at steady state, in the case with no accumulation of mass, the flux of solute to the membrane surface can be balanced by solute fluxes flowing away from the membrane and through the membrane as following[16]: …(6) where: m is the solute mass (mg), t is the time (s), is the solute diffusion coefficient in water (m 2 /s), z is the distance perpendicular to the surface of membrane (m) and a is the surface area of membrane (m 2 ). equation 6 can be not only applied at the surface of membrane but also at any plane in the boundary layer because the net flux of solute must be constant everywhere in the boundary layer to prevent the solute accumulation in that layer. integrating equation 6 across the thickness of the boundary layer with the boundary conditions: c(0) = and c( ) = , where is the feed concentrate channel concentration and is the membrane surface concentration. ∫ ∫ …(7) integrate equation 7 as: ( ) …(8) …(9) the concentration polarization is expression used to characterize the accumulation of rejected solute at the membrane surface so that the concentration of solute at the wall of membrane is greater than of the bulk http://www.iasj.net/ experimental study and mathematical modelling of zinc removal by reverse osmosis membranes www.iasj.netavailable online at: 6) 201 september( 3no. 7ijcpe vol.1 06 solution of feed. the convective flow of solute to the surface of membrane is greater than the diffusion back to the bulk feed solution; so that, the solute concentration at the wall of membrane increases [19]. negative effects of concentration polarization involve [20]: 1changes in membrane separation properties. 2declines in the flux of water because of increased in osmotic pressure at the wall of membrane. 3enhanced fouling by colloidal or particulate materials in the feed which plug the surface of membrane and decrease the flux of water. 4increases in the flux of solute over the membrane due to increased concentration gradient across the membrane. 5the solute precipitation if the concentration of surface exceeds its solubility limit, leading to particle fouling or scaling on membrane and reduced the flux of water. concentration polarization is defined as the ratio of the solute concentrations of membrane and feed concentrate channel as: …(10) where: is the concentration polarization factor (dimensionless). combining equation 10 with equations 5 and 9 gives the following expression: ⁄ ) …(11) schock and miquel [21] found that the mass transfer coefficient of concentration polarization could be calculated from equations below: …(12) …(13) …(14) where: = is the mass transfer coefficient of concentration polarization (m/h), is the hydraulic diameter (m), re is the reynold number (dimensionless), sc is the schmidt number (dimensionless), is the velocity in the feed channel (m/h), is the density of feed water (kg/m 3 ) and μ is the dynamic viscosity of feed water (kg/m.s). as shown in figure 1 the center plane of a differential slice of membrane performs the surface of membrane. the feed concentrate channel overhead the membrane, the permeate channel below the membrane. fig. 1: differential slice of membrane element the water and solute fluxes are expressed by equations 1 and 3, but the concentration differential, osmotic pressure differential and applied pressure differential rely on the position in the pressure vessel [16]: [( ) ( )] …(15) ( ) …(16) http://www.iasj.net/ ahmed faiq al-alawy and miqat hasan salih 06 )6201september ( 3no. 17ijcpe vol. www.iasj.netonline at: available where: is the concentration at the surface of membrane, and is the osmotic pressure at the surface of membrane. the flow of permeate and flow of mass of solute through the membrane are equal to the flux multiply by the area of membrane for the differential element. the accumulative water and solute transfer across the membrane is predicted by integrating the flow between the feed end and the position z in the pressure vessel, as: ∫ …(17) ∫ …(18) where: w is the width of feed concentrate channel (m) and is the solute mass transferred (mg/s). flow rate of water in the feed concentrate channel decreases as the permeate is produced. at any point in the channel the flow rate can be predicted by [16]: …(19) the concentration of solute in the feed concentrate channel can be calculated by doing a mass balance on solute as: …(20) the flux of water and solute are influenced by solute concentration at the membrane surface and concentration polarization. both velocity and flux are changing, must be determined by equation 11 as a function of position, as the following equation: ( ) …(21) the velocity in the feed concentrate channel which mass transfer coefficient depends on it can be calculated from the following equation: …(22) where h is the height of feed concentrate channel (m). the concentration of solute at the surface of membrane as a function of position expressed as: …(23) the feed channel pressure drops because of the head loss, head loss changes across the length of the membrane. turbulent conditions are maintained, so head loss in the channel is given by the expression: …(24) where: is the feed concentrate channel head loss (bar), is the head loss coefficient (bar.s 2 /m 3 ), is the velocity of water in feed concentrate channel (m/s) and l is the length of the channel (m). the concentration of permeate can be determined from the ratio of the fluxes of solute and water per equation 4 as: …(25) 2. unsteady steady state calculations recovery can be expressed as the volume of permeate divided by the initial volume of feed. this expression applied in batch concentrating mode. for the overall system, the expression is [22]: …(26) http://www.iasj.net/ experimental study and mathematical modelling of zinc removal by reverse osmosis membranes www.iasj.netavailable online at: 6) 201 september( 3no. 7ijcpe vol.1 06 where: is the recovery (percentage), is the volume of permeate (l) and is the initial feed volume (l). reverse osmosis unit in continuous operation consists of a tank for feed, a tank for product and the membrane element. the concentrate is recycled back to the tank of feed and the permeate is separately collected in the product tank as shown in figure 2 [23]. fig. 2: reverse osmosis system material balance equation applied for the product tank as: …(27) is the product average concentration (mg/l). expansion of equation 27 yields: …(28) initial conditions, at t=0, =0, = =0. the variation in the product volume corresponds to the production rate of membrane as: …(29) substitution to equation 28: …(30) material balance on the membrane element gives: …(31) analogous material balance equation can be obtained around the feed tank: …(32) developing this equation gives: …(33) where, is the volume in the tank of feed at a time t, with a concentration in the tank . the tank of feed is assumed well mixed [22] so: …(34) and: …(35) http://www.iasj.net/ ahmed faiq al-alawy and miqat hasan salih 06 )6201september ( 3no. 17ijcpe vol. www.iasj.netonline at: available the variation in the feed tank volume with time corresponds to the production rate as: …(36) integrating equation 36 with the initial condition: t=0, …(37) substituting these expressions in equation 33: …(38) knowing that the system of interest is closed, the conservation of mass reveals that the solute mass in feed tank at initial time is equal to the sum of various streams and tank: …(39) substituting by its expresssion in equation 30: …(40) equation 38 and 40 are the outcome of material balances on the product tank, feed tank, and membrane element. the solution of this set of ordinary differential equations requires the values of and . and are obtained from the steady state equations 4 and 17 as initial values for the ordinary differential equations when the concentration and product rate of permeate change with position of module. the solution of equation 38 gives the concentration of feed as function of time. the solution of equation 40 gives the solute average concentration in product tank and the volume of water by equation 39. the equations of the mathematical model can be solved by using matlab program. experimental work synthetic wastewater containing the desired concentrations of zn +2 were prepared by dissolving the desired amount of zinc chloride (zncl2, minimum assay 97%, m.w. 136.28, cas-no. 7646-85-7 un 2331, india) in deionized water of conductivity 1-2 µs/cm. commercially spiral-wound ultra low pressure aromatic polyamide reverse osmosis membrane element is used in this work, can work under ultra low pressure to attain as high permeate flow rate and salt rejection as low pressure membrane element can, the specifications of this module are given in table 1. schematic diagrams of lab-scale ro system used in these experiments are shown in figure 3. feed solution was prepared in feed vessel by dissolving the zncl2 in 8 liter of deionized water. pressure gauge (range: 0-10 bar) is used in the feed line to indicate the operating pressure, the feed solution drawn from the feed vessel by centrifugal pump (model: 15 gr-18, rated power: 150 w, rated voltage: 220-240 v, rated current: 0.58 a, rated speed: 2860 r/min, frequency: 50/60 hz, highest head: 15 m, rated head: 10 m, max. capacity: 25 l/min, rated capacity: 10 l/min, insulation class: b) then the solution is introduced into the spiral-wound reverse osmosis element by means of a high pressure pump (model: hf-6050, max. outlet pressure: 125 psi, open flow: 1.2 l/min, volts: 24 vdc, amps: 0.26 a). the feed temperature was varied by submersible electrical coil (rated power: 1000 w, rated voltage: 220v). the feed flow rate was controlled by rotameter (range: 10100 l/h) and keeping constant at 40 l/h. the concentrate stream is recycled to http://www.iasj.net/ experimental study and mathematical modelling of zinc removal by reverse osmosis membranes www.iasj.netavailable online at: 6) 201 september( 3no. 7ijcpe vol.1 06 the feed vessel and mixed with the feed stream. the water flux was obtained by dividing the permeate volume by the product of effective area of membrane and time. the concentration of heavy metal ion (zn +2 ) was measured by an atomic absorption spectrometry (buck 210/211, u.s.a., perkin elmer, sr.nr:1159 a). after recording the results, the solution was drained by a drain valve and the system was washed by deionized water. table 1: specification of reverse osmosis element model vontron-ulp 1812-50 type of membrane ultra low pressure aromatic polyamide reverse osmosis membrane element active membrane area, m 2 0.36 average permeated flow, m 3 /d 0.19 stable rejection rate, % 97.5 minimum rejection rate, % 96 testing pressure, mpa 0.41 concentration of testing solution (nacl), ppm 250 ph of testing solution 7.5 recovery of single membrane element, % 15 maximum working pressure, mpa 2.07 maximum feed water temperature, °c 45 maximum feed water sdi 5 free chlorine concentration of feed water, ppm <0.1 ph range of feed water during continuous operation 3-10 ph range of feed water during chemical cleaning 2-12 fig. 3: schematic diagram of lab-scale ro system results and discussion the aromatic polyamide membrane permeability ( ) for pure water was experimentally determined by a hydraulically low pressure ro process. the pure water flux through the http://www.iasj.net/ ahmed faiq al-alawy and miqat hasan salih 08 )6201september ( 3no. 17ijcpe vol. www.iasj.netonline at: available membrane was determined with range of pressures according to equation 1 when . as shown in figure 4, the data shows a linear relationship between water flux and driving force. aromatic polyamide compound membrane permeability for pure water is determined from the slope of this curve, the value of was obtained 6.736 l/m 2 .bar.h. fig. 4: operating pressure vs. water flux (q f = 30 l/h, t = 26 o c and t=10 min) the membrane permeability ( ) for salt (zncl2) was experimentally determined under a range of feed concentrations according to equation 3. as shown in figure 5, the data show a linear relationship between mass flux of solute and driving force. membrane permeability for salt is determined from the slope of this curve, the value of was obtained 2.498*10 -4 m/h. fig. 5: concentration difference vs. solute flux (qf=40 l/h, t=26 o c , t=30 min and p=2 bar) figure 6 show the effect of time on the concentration of zinc ion in permeate. the heavy metal ions concentration in the product gradually increased with the increase in operating time. this behavior can be explained by the increase of the feed concentration with time in the recirculation mode led to increase in concentration polarization and this cause an increase in the zinc 0 5 10 15 20 25 30 35 40 0 1 2 3 4 5 6 w a te r f lu x ( jw ), l m h pressure, bar 0 50 100 150 200 250 0 200 400 600 800 1000 s o lu te f lu x ( j s ), m g /m 2 .h cf cp, mg/l http://www.iasj.net/ experimental study and mathematical modelling of zinc removal by reverse osmosis membranes www.iasj.netavailable online at: 6) 201 september( 3no. 7ijcpe vol.1 00 passage, this behavior is agreement with xiuzhen [13]. the first 30 minutes resulted in the increase in permeate concentration of 17.72% and the final 40 minutes resulted in the increase in permeate concentration of 52.58%. fig. 6: effect of operating time on permeate concentration of zinc ions (q f = 40 l/h, t = 26 o c, ph = 6, p = 2 bar, czn+2=300 mg/l) fig. 7: effect of operating time on rejection of zinc ions (q f = 40 l/h, t = 26 o c, ph = 6, p = 2 bar, czn+2=300 mg/l) as shown in figure 7 the rejection rates of zinc ions have been randomly decreased and increased in spite of that the concentration of zinc ions in permeate has been increased with time, this behavior due to the increase in feed concentration (feed concentration has been changed with time) because of the recirculation mode. the rejection for zinc ion at first three minutes when the feed concentration approximately constant (300 mg/l) is 99.49%. figure 8 shows the effect of time on flux. it can be easily observed that the flux from reverse osmosis unit decrease with increase in operating time. the continuous decrease of the flux was mainly due to the gradual increase in the viscosity of solution 0 2 4 6 8 10 0 10 20 30 40 50 60 70 80 c p z n + 2 , m g /l time, min 98 98.2 98.4 98.6 98.8 99 99.2 99.4 99.6 0 10 20 30 40 50 60 70 80 r e je ct io n , % time, min http://www.iasj.net/ ahmed faiq al-alawy and miqat hasan salih 06 )6201september ( 3no. 17ijcpe vol. www.iasj.netonline at: available and to heavy metal deposition onto the membrane surface with increasing feed concentration and osmotic pressure gradually, which led to further membrane fouling and severe concentration polarization. resistance against water flux through the membrane increased due to the boundary layer on the membrane surface formed by heavy metals. furthermore, increasing osmotic pressure because of concentration polarization led to a decrease in the driving force through the membrane. this behavior is agreement with xiuzhen and zhi [13, 24]. the increase in time to 70 min resulted in the flux decline of 6.226%. fig. 8: effect of operating time on flux (q f = 40 l/h, t = 26 o c, ph = 6, p = 2 bar, czn+2=300 mg/l) figure 9 shows the effect of time recovery percentage of permeate. the recovery percentage increase according to equation 26 because the accumulation volume of permeate has been increased as time increased. the increase in time to 70 min resulted in the increase of water recovery from 8.3125 to 54.5625%. fig. 9: effect of operating time on recovery percentage (q f = 40 l/h, t = 26 o c, ph = 6, p = 2 bar, czn+2=300 mg/l) 9 9.5 10 10.5 11 11.5 12 0 20 40 60 80 f lu x , lm h time, min theo. exp. 0 10 20 30 40 50 60 70 80 0 10 20 30 40 50 60 70 80 r e co v e ry , % time, min theo. exp. http://www.iasj.net/ experimental study and mathematical modelling of zinc removal by reverse osmosis membranes www.iasj.netavailable online at: 6) 201 september( 3no. 7ijcpe vol.1 05 figure 10 shows the values of final feed vessel concentration change with time. it can be observed that the feed concentration increase with increase in operating time. this behavior was due to the recirculation mode (concentrate stream recycled to the feed stream). fig. 10: effect of operating time on final feed concentration (q f = 40 l/h, t = 26 o c, ph = 6, p = 2 bar, czn+2=300 mg/l as shown in figure 11 zinc concentration in permeate has been increased as the feed concentration increased, this behavior is agreement with kyu [25]. the increase in feed concentration ion from 10 to 300 mg/l resulted in the increase of permeate concentration from 0.19 to 4.63 mg/l. fig. 11: effect of feed concentration on permeate concentration of zinc ions (q f = 40 l/h, t = 26 o c, ph = 6, p = 2 bar, t=30 min) it is clear from figures 12 and 13 that the permeate flux and recovery have been decreased with increasing feed concentration. this behavior due to increase in osmotic pressure, decrease of the effective membrane pore size due to adsorption of solute on the membrane surface and the effect of concentration polarization, this behavior is agreement with kyu [25]. the decrease in recovery according to decrease in flux. the increase in feed 600 800 1000 1200 1400 1600 0 20 40 60 80 t d s z n c l2 f in a l in f e e d , m g /l time, min theo. exp. 0 1 2 3 4 5 0 50 100 150 200 250 300 350 c p z n + 2 , m g /l cf zn +2, mg/l http://www.iasj.net/ ahmed faiq al-alawy and miqat hasan salih 05 )6201september ( 3no. 17ijcpe vol. www.iasj.netonline at: available concentration ion from 10 to 300 mg/l resulted in the decrease of recovery from 30.81% to 24.5% and flux from 13.694 to 10.889 lmh. figure 14 show the values of final feed vessel concentration. it can be observed that the feed concentration increase with increase in ion feed concentration. this behavior due to the recirculation mode (concentrate stream recycled to the feed stream). fig. 12: effect of feed concentration on flux (q f = 40 l/h, t = 26 o c, ph = 6, p = 2 bar, t=30 min) fig. 13: effect of feed concentration on recovery percentage (q f = 40 l/h, t = 26 o c, ph = 6, p = 2 bar, t=30 min) figure 15 shows that the zinc concentration in permeate has been decreased with increasing applied pressure which can be explained by the following: the decrease in concentration of ion in permeate with raise in pressure could be because of at higher pressure the preferential sorption of the membrane element for pure water has been increased and the average pore size on the membrane surface has been decreased, also due to increase in flux with increasing applied pressure. in other words, at low pressure the solute diffusive transport through membrane is higher than that of convective transport. as the applied pressure increases, convective 10 10.5 11 11.5 12 12.5 13 13.5 14 0 50 100 150 200 250 300 350 f lu x , lm h cf zn +2, mg/l theo. exp. 22 24 26 28 30 32 0 50 100 150 200 250 300 350 r e co v e ry , % cf zn +2, mg/l theo. exp. http://www.iasj.net/ experimental study and mathematical modelling of zinc removal by reverse osmosis membranes www.iasj.netavailable online at: 6) 201 september( 3no. 7ijcpe vol.1 66 transport becomes more important which make it possible to decrease the concentration of ion in permeate, this behavior is agreement with xijun [26]. the increase in pressure from 1 to 4 bar resulted in the decrease of permeate concentration of zinc ion of 49.927%. fig. 14: effect of feed concentration on final feed concentration (q f = 40 l/h, t = 26 o c, ph = 6, p = 2 bar, t=30 min) fig. 15: effect of applied pressure on permeate concentration of zinc ions (q f = 40 l/h, t = 26 o c, ph = 6, czn+2=300 mg/l, t=30 min) as shown in figures 16 and 17 the permeate flux and recovery has been increased linearly with increasing applied pressure, this means that there is a little effect of concentration polarization in the membrane module. this behavior can be explained by the permeability equation of solution diffusion model (equation 1), this behavior is agreement with jae [27]. the increase in applied pressure from 1 to 4 bar resulted in the increase of flux of 311.979%. figure 18 shows the values of final feed vessel concentration. it can be observed that the feed concentration increase with increase in applied pressure. this behavior due to the recirculation mode (concentrate stream recycled to the feed stream). 0 100 200 300 400 500 600 700 800 900 1000 0 50 100 150 200 250 300 350 t d s z n c l2 f in a l in f e e d , m g /l cf zn +2, mg/l theo. exp. 2 3 4 5 6 7 8 0 1 2 3 4 5 c p z n + 2 , m g /l applied pressure, bar http://www.iasj.net/ ahmed faiq al-alawy and miqat hasan salih 66 )6201september ( 3no. 17ijcpe vol. www.iasj.netonline at: available it can be seen from figures 8, 9, 10, 12, 13, 14, 16, 17 and 18 that the model prediction values are in good agreement with the experimental results. fig. 16: effect of applied pressure on flux (q f = 40 l/h, t = 26 o c, ph = 6, czn+2=300 mg/l, t=30 min) fig. 17: effect of applied pressure on recovery percentage (q f = 40 l/h, t = 26 o c, ph = 6, czn+2=300 mg/l, t=30 min) fig. 18: effect of applied pressure on final feed concentration (q f = 40 l/h, t = 26 o c, ph = 6, czn+2=300 mg/l, t=30 min) 0 5 10 15 20 25 0 1 2 3 4 5 f lu x , lm h applied pressure, bar theo. exp. 8 13 18 23 28 33 38 43 48 53 0 1 2 3 4 5 r e co v e ry , % applied pressure, bar theo. exp. 500 700 900 1100 1300 1500 0 1 2 3 4 5 t d s z n c l2 f in a l in f e e d , m g /l applied pressure, bar theo. exp. http://www.iasj.net/ experimental study and mathematical modelling of zinc removal by reverse osmosis membranes www.iasj.netavailable online at: 6) 201 september( 3no. 7ijcpe vol.1 66 conclusion the aromatic polyamide reverse osmosis membrane gives a high efficiency for removal of zinc ions and it has allowed permeation of zinc ion to the lower than permissible limits. the rejection percentage for zinc ion was high (i.e. ˃ 98%) for most experiments in this research. the recovery percentage for reverse osmosis element was 54.56% during the time of 70 minutes. the polyamide membrane permeability for zinc chloride is 2.498*10 -4 m/h. the theoretical flux values calculated from mathematical model are in a good agreement with the experimental results. references 1. salem alzahrani, a.w. mohammad, n. hilal, pauzi abdullah, othman jaafar, "comparative study of nf and ro membranes in the treatment of produced water—part i: assessing water quality", desalination, vol.315, p.p.18-26, (2013). 2. fenglian fu, qi wang, "removal of heavy metal ions from wastewaters: a review", journal of environmental management, vol.92, p.p.407-418, (2011). 3. m.a. barakat, "new trends in removing heavy metals from industrial wastewater", arabian journal of chemistry, vol.4, p.p.361–377, (2011). 4. tonni agustiono kurniawan, gilbert y.s. chana, wai-hung loa, sandhya babel, "physico–chemical treatment techniques for wastewater laden with heavy metals", chemical engineering journal, vol.118, p.p. 83–98, (2006) 5. n.k. srivastava, c.b. majumder, "novel biofiltration methods for the treatment of heavy metals from industrial wastewater", journal of hazardous materials, vol.151, p.p.1-8, (2008). 6. m. ahmaruzzaman, " industrial wastes as low-cost potential adsorbents for the treatment of wastewater laden with heavy metals", advances in colloid and interface science, vol.166, p.p. 36– 59, (2011). 7. r. m. abhanga, k.s. wani, v.s. patil, b.l. pangarkar, s.b. parjane, "nanofiltration for recovery of heavy metal ions from waste water a review", international journal of research in environmental science and technology, vol.3(1), p.p.2934, (2013). 8. r. abdel wahaab, a.k. moawad, enas abou taleb,hanan s. ibrahim and h.a.h. el-nazer, "combined photocatalytic oxidation and chemical coagulation for cyanide and heavy metals removal from electroplating wastewater", world applied sciences journal, vol.8 (4), p.p.462-469, (2010). 9. ministry of iraqi environment. 10. wen-ping zhu, jie gao, shipeng sun, sui zhang, tai-shung chung, "poly(amidoamine) dendrimer (pamam) grafted on thin film composite (tfc) nanofiltration (nf) hollow fiber membranes for heavy metal removal", journal of membrane science, vol.487, p.p. 117–126, (2015). 11. cristina-veronica gherasim, petrmikulášek, "influence of operating variables on the removal of heavy metal ions from aqueous solutions by nanofiltration", desalination, vol.343, p.p.67–74, (2014). 12. amin maher, morteza sadeghi, ahmad moheb, "heavy metal elimination from drinking water using nanofiltration membrane technology and process optimization using response surface http://www.iasj.net/ ahmed faiq al-alawy and miqat hasan salih 66 )6201september ( 3no. 17ijcpe vol. www.iasj.netonline at: available methodology", desalination, vol.352, p.p.166–173, (2014). 13. xiuzhen wei, xin kong, songxue wang, hai xiang, jiade wang, and jinyuan chen, "removal of heavy metals from electroplating wastewater by thinfilm composite nanofiltration hollow-fiber membranes", industrial & engineering chemistry research, vol. 52, p.p.17583−17590, (2013). 14. ahmed faiq al-alawy, "performance of manipulated direct osmosis in water desalination process", ph.d. thesis, university of baghdad, (2007). 15. myzairah binti hamdzah, "low pressure reverse osmosis membrane for rejection of heavy metals", msc. thesis, university teknologi malaysia, (2007). 16. john c. crittenden, r. rhodes trussell, david w. hand, kerry j. howe, george tchobanoglous, a book of "mwh’s water treatment principles and design", published by john wiley and sons, inc., third edition, p.p. 13351414, (2012). 17. jane kucera, a book of "reverse osmosis design, processes, and applications for engineers", published by scrivener publishing llc, p.p.41-84, (2010). 18. woodyian n. khudair, "reduction of concentrating poisonous metallic radicals from industrial wastewater by forward and reverse osmosis", msc. thesis, university of baghdad, (2011). 19. michael e. williams, "a review of reverse osmosis theory", corporation and williams engineering services company, inc., (2003). 20. tamara kawther hussein, "forward osmosis for removal of lead, copper and nickel from aqueous solutions", ph.d. thesis, university of baghdad, (2015). 21. schock, g., and miguel, a., "mass transfer and pressure loss in spiral wound modules", desalination, vol.64, p.p. 339–352, (1987). 22. belkacem absar, sid el mahi lamine kadi and omar belhamiti, "mathematical modeling of reverse osmosis process by the orthogonal collocation on finite element method", asian journal of applied sciences, vol.1(1), p.p.1-18, (2008). 23. jamal k., m. khan and m. kamil, "mathematical modelling of reverse osmosis", desalination, vol.160, p.p. 29–42, (2004). 24. zhi wang, guangchun liu, zhifeng fan, xingtao yang, jixiao wang, shichang wang, "experimental study on treatment of electroplating wastewater by nanofiltration", journal of membrane science, vol.305, p.p. 185–195, (2007). 25. kyu-hong ahn, kyung-guen song, ho-young cha, ick-tae yeom, "removal of ions in nickel electroplating rinse water using low-pressure nanofiltration", desalination, vol.122, p.p.77-84, (1999). 26. xijun chai, guohua chen, polock yue, yongli mi, " pilot scale membrane separation of electroplating waste water by reverse osmosis", journal of membrane science, vol.123, p.p.235-242, (1997). 27. jae-wok lee, tae-ouk kwon, il-shik moon, "performance of polyamide reverse osmosis membranes for steel wastewater reuse", desalination, vol.189, p.p. 309-322, (2006). http://www.iasj.net/ g.a. rassoul and d.r. rzaige ijcpe vol.9 no.3 (2008) iraqi journal of chemical and petroleum engineering vol.9 no.3 (december 2007) 37-41 issn: 1997-4884 electrocoagulation of phenol for wastewater treatment ahmed a-mohammed environmental engineering department college of engineering university of baghdad – iraq abstract electrocoagulation is an electrochemical process of treating polluted water where sacrificial anode corrodes to produce active coagulant (usually aluminum or iron cations) into solution. accompanying electrolytic reactions evolve gas (usually as hydrogen bubbles). the present study investigates the removal of phenol from water by this method. a glass tank with 1 liter volume and two electrodes were used to perform the experiments. the electrode connected to a d.c. power supply. the effect of various factors on the removal of phenol (initial phenol concentration, electrode size, electrodes gab, current density, ph and treatment time) were studied. the results indicated that the removal efficiency decreased as initial phenol concentration increased, the highest removal obtained at ph in the range (6-8), the removal enhanced with increasing electrode size and decreasing the gab between the electrodes. the optimum current density obtained at 221 a/m2. key words: electrocoagulation, flotation, phenol, wastewater introduction with the development of industry, more and more pollutants are discharged into environment, among them, phenolic wastes are typical contaminates considered to be hazardous and top priority toxic pollutants listed by the usepa. they are toxic even at low concentration, the treatment of these contaminants is very important in environmental protection.[1].various technologies and processes have been tried for treating phenol contaminates, electrocoagulantion is an advanced method for the treatment of phenol. electrochemistry, coagulation and flotation are identified as the key foundation sciences for electrocoagulation. electrocoagulation uses an electrochemical cell to treat polluted water a sacrificial metal anode (usually aluminum but sometimes iron) is used to dose polluted water with a coagulant agent. electrolytic gases are generated (typically hydrogen at cathode [2,3]. the coagulant’s delivery and its nature influenced the coagulation and separation process by its speciation, removal path and associated by-product electrolytic gases [4]. electrocoagulation has the capability to remove a wide range of pollutants including suspended solids, heavy metals, dyes, organic material. fog’s (i.e, fats, oils and greases), ions and radionuclides [5,6,7]. electrocoagulation has been compared to chemical coagulation to assess its efficiency and advantages. chemical dosing delivers the coagulants as a salt that dissociates in the solution with hydrolysis of the aluminum action determining solution speciation and ph. alum (i.e aluminum sulphate ) addition acidifies the water. by contrast, aluminum added via electrocoagulation does not bring with any associated salt anions, with the result that the ph typically stabilizes in the alkaline range [8]. the aluminium cation has a variety of paths available (depending upon the treatment properties, solution ph and concentration), it could directly interact with the pollutants, it could hydrolyse to form a hydro-aluminium complex, or it could precipitate [9]. the active metal cation (produced at the anode) reacts with hydroxide ions (produced at the cathode) to form a metal hydroxide which then acts as a coagulant, with the pollutant particles and metal hydroxides forming larger aggregates which may either settle out or be carried to the surface by hydrogen bubbles produced at the cathode [11]. the equilibrium for the aluminum water system occurs as a result of passivation (i.e. formation of an oxide layer) and corrosion is identified. the presence of the chloride university of baghdad college of engineering iraqi journal of chemical and petroleum engineering effect of temperature on corrosion of carbon steel boiler tubes in dilute soduim chloride solution 2 ijcpe vol.9 no.3 (2008) ion in solution has been reported to decrease passivation and thereby increase electrocoagulation pollutant removal efficiency [10,11]. the mechanism for chloride ion reducing passivation of the oxide layer formed on aluminum as shown in equations below [2]. al+3hcl alcl3+h2 alcl3+3h2o al(oh)3+3hcl the electrocoagulation process is characterized by a fast rate of pollutant removal, compact size of the equipment, simplicity in operation and low operating and equipment costs [12]. the electrolytic bubbles are typically small (less than 50 µm in diameter) close to neutral buoyancy, and present in low concentration. for a given gas volume a smaller bubble diameter results in both a greater surface area and more bubbles, thereby increasing the probability of collision and the ability to remove fine pollutant particles [13]. materials and methods the polluted water was prepared using phenol provided by (sdfine-chem. limited india). hydrochloric acid and sodium hydroxide were used as ph modifiers and the control was affected by means of digital ph meter. 4 grams of sodium chloride were added to the solution to increase the conductivity of the solution and to prevent the formation of the oxide layer on the anode and therefore reduced the passivation problem of the electrodes [10]. experimental apparatus: electrochemical removal of phenol from water was carried out in the electrochemical cell shown in figure (1) the internal size of the reactor (10*10*12 cm) (width*length*depth) with an effective volume of 1 liter. two electrodes were used, the first one aluminum electrode as anode and the other one iron as cathode. power supply having an input of 220 v and variable output of (0-30 v) with a maximum current of 3 amper was used as a direct current source. samples were taken every 20 minutes and analyzed for phenol concentration by using uv160 apparatus at 270 nm. the equation used to calculate the phenol percent recovery in the treatment experiment was: where: co=initial phenol concentration. c=present phenol concentration. r=recovery. fig.1: electrocoagulation apparatus results and discussion as pointed previously that the main reaction occurring during the electrolysis in the electrochemical cell produced aluminum ion at the cathode and hydroxide ion as well as hydrogen at the cathode as shown below: anode reaction al al3+ + 3e cathode reaction 2h20+2e 2oh+h2 the aluminum ion that resulted from anode reaction reacts with hydroxyl ion to form gelatinous aluminum hydroxide al(oh)3 thus effects the coagulation of phenol from the solution by adsorption. also the aluminum ion liberated from the anode may interact directly with phenol which then precipitates out of the solution in the form of an insoluble salt ,e.g. aluminumtriphenolate [al(oar)3][14]. in electrocoagulation the electrodes of the electrochemical cell are connected to an electrical power source, the relationship between current density (a/cm2)and the amount of aluminum which goes into solution (g al cm-2) can be calculated by using faraday’s law[9]: where: w=aluminum dissolving (g al cm-2). i=current density (a/cm2). t= time (s). m= molecular weight of al (m=27). z=number of electrodes involved in the oxidation reduction reaction (z=3) f= faraday’s constant (96500). g.a. rassoul and d.r. rzaige ijcpe vol.9 no.3 (2008) during the experiments, the al-electrode was weighted. the theoretically calculated amount of al dissolved compared with the weighted values of al dissolved is plotted in fig.(2), the correlation found was (r2=0.97) and in the further experiments the al dissolved was calculated based on faraday’s law. fig.2: calculated vs. weighted amount of al dissolved the influenced of current density on the percent recovery of phenol from water is carried out at 40 °c. in addition the initial phenol concentration is 50 ppm and aluminum and iron electrode sizes of (10*5*0.05 cm) were used. as shown in figure (3) it can be seen that an increase in the percent recovery from (33 to 88 %) yields with an increase in current density from (49.3 to 246 a/m 2 ) and this due to that with an increased in the current density, the ion production on both anode and cathode increased resulted in an increasing in the floc production in the solution. in addition bubbles density increases and their sizes decrease resulting in both greater upward momentum flux and increasing mixing. so that the optimum current density for a solution with phenol concentration of 50 ppm was 221 a/m 2 . fig.3: effect of current density on the phenol percent recovery (ph=6, 40 °c, 50 ppm) three different sizes of electrodes (10x5, 10x3, 10x2) cm 2 is used to investigate the effect of the electrode size on the percent recovery. the result is shown in figure (4), from this figure it can be seen that the electrode size of (10x5x0.05cm) had a better percent recovery than the other two smaller sizes, the explanation of this phenomena as follows: larger electrode surface area resulted in a greater dispersion of bubbles throughout the reactor, whereas a smaller electrode surface resulted in a concentrated source of bubbles within the reactor, and with increasing the dispersion of bubbles in the reactor probability of collision between the bubbles and coagulant increased leading to increase the percent recovery. the effect of electrodes spacing (2.0, 2.5 and 3.0 cm) is plotted in figure (5) and it can be concluded from this figure that the efficiency increased with decreased the gab between the electrodes. effect of temperature on corrosion of carbon steel boiler tubes in dilute soduim chloride solution 4 ijcpe vol.9 no.3 (2008) fig.4: effect of electrode size on phenol removal efficiency (ph=6 , 40 °c, 50 ppm, 221 a/m 2 ) fig.5: effect of electrode spacing on phenol removal efficiency (ph=6 , 40 °c, 50 ppm, 221 a/m 2 ) the effect of initial phenol concentration (50,100,150,200 ppm) on the percent recovery is shown in figure (6). it can be seen that at high phenol concentration (200 ppm) the removal rate was very fast at first (20 minutes) and then became very slow later, with increasing phenol concentration the removal efficiency decreased because at the same condition the flocs and hydrogen production is constant value resulted in a decrease in the adsorption capacity and flotation rate. up to the first (120 min) the adsorption capacity of flocs was not exhausted and with progressive of the reaction time desorption to the solution took place resulted in decrease of phenol removal efficiency especially at the higher concentration. ph has a considerable effect on the efficiency of the electrocoagulation process(12), also the ph of the medium change during the process. this change depends on the type of electrode material and initial ph. in this study the ph was studied in the range (3-11), the solution was adjusted to the desired ph for each experiment by adding hcl or naoh, the ph of the solution increased by about (1-2 unit) at the first (2-3 minutes) and then decreased. the effect of ph on the percent recovery is plotted in figure (7), from this figure it can be seen that the removal rate increased with a decreased in the ph. when ph was 6 the reaction was so fast that it takes only (90 minutes) to reach (85 %) removal efficiency. at ph higher than 10 it took about 30 minutes more than that when ph about 6 to achieve nearly the same percent recovery, this due to that when the ph is lower than 6 al(oh)3 is insoluble from (al+3) and when it is higher than 8 al(oh)3 is insoluble from [al(oh)4] and because al(oh)3 has major role in removing of phenol, thus when ph of solution in the range (6-8) phenol removal is higher [9]. fig.6: effect of initial phenol concentration on the removal efficiency (ph=6 , 40 °c, 221 a/m 2 ) g.a. rassoul and d.r. rzaige ijcpe vol.9 no.3 (2008) fig. 7: effect of solution ph on the phenol removal efficiency (50 ppm, 40 °c, 221 a/m 2 ) conclusions the removal of phenol from water by electrocoagulation process was effected by various variables as follows: 1. the removal efficiency increased (33-88 %) with increasing current density in the range (49-221 a/m 2 ) and this was due to that an increase in current density resulted in an increase in the floc production and an increase in the hydrogen generated at cathode which increased the flotation efficiency of the produced sludge. 2. with increasing initial phenol concentration the time required for process should increase too, but that higher initial concentrations of phenol were reduced in relatively less time than the lower concentrations. 3. the best removal achieved when the ph of solution in the range (6-8). 4. with respect to the electrode sizes, the best removal obtained at the higher electrode surface area and lower spacing between the electrodes due to greater dispersion of bubbles throughout the reactor. 5. a good agreement between the theoretically calculated amount of al dissolved and the experimentally weight value. reference 1) cong,y.q., cheng,w.z.,yian,y.e.,” degradation of chlorophenol by in-situ electrochemically generated oxidant” j.zhejiang university science, 5(2), 180-185 (2004). 2) mameri,n.,lounici,h. and grib,h. “ defluoridation of sahara water by small plant electrocoagulation using bipolar aluminium electrodes” water research 32(5), 1604-1612 (1998). 3) vike,e.a.,carlson,d.a. and eikun, a.s.” electrocoagulation of potable water”.water research 18(11),1355-1360 (1984). 4) holt p.k.,barton, g.w. and mitchell,c.a. “electrocoagulation as a wasterwater treatment”.in the third annual australian environmental engineering research event.(1999). 5) abu zaid,n.s.,bukhari,a.a. and al-hamouz,z.m “removal of bentonite causing turbidity by electrocoagulation” journal of environmental science and health part a” toxic/hazardous substances and environmental engineering a33(7),1341-1358 (1998). 6) gnusin,n.p and zabolotskaya, l.i “effect of ph,electrical and hydrodynamic regimes on electrocoagulation treatment of solution containing cd + “ soviet journal of water chemistry and technology 7(4),32-35 (1985). 7) cames, m.c., tanguy. g leclerc,j.p.”design rules of pilot cell for treatment of concentrated liquid wastes by electrocoagulation-electroflotation”,in 6 th world congress of chemical engineering conference media cd,melbourne.australia (2001). 8) koparal,a.s. and ogutveren,u.b.“removal of nitrate from water by electroreduction and electrocoagulation”. journal of hazardous materials b89, 83-94,(2002). 9) holt,p.k. “ elctrocoagulation: unravelling and synthesizing the mechanisms behind a water treatment process” ph.d thesis, faculty of engineering, the university of sydney (2003). 10) sleptsov,g.v.,gladkii,a.i, and sokol,e.y “electrocoagulation treatment of oil emulsion wastewater of industrial enterprises”. soviet surface engineering and applied electrochemistry.(6),96-99 (1987). 11) jiaqian, j.” an anodic passivation of electrocoagulator in the process of water treatment”. water treatment 3,344-352, (1988). 12) chen,x.,chen,g. and yue,p.l” separation of pollutants from restaurant wastewater by electrocoagulation”. separation purification technology” 19,65-76,(2002). effect of temperature on corrosion of carbon steel boiler tubes in dilute soduim chloride solution 6 ijcpe vol.9 no.3 (2008) 13) matis,k.a. “flotation science and engineering” marcel dekker,new york. (1995). 14) weerachai, p.,sombat,c and duang,b “electrocoagulation and subsequent recovery of phenolic compounds” japan society for analytical chemistry, october vol 16, (2002). iraqi journal of chemical and petroleum engineering vol.18 no.2 (june 2017) 83 93 issn: 1997-4884 adsorption kinetic and isotherms studies of thiophene removal from model fuel on activated carbon supported copper oxide saad h. ammar and sama ali jaafar chemical engineering department – college of engineering al-nahrain university abstract in the present study, activated carbon supported metal oxides was prepared for thiophene removal from model fuel (thiophene in n-hexane) using adsorptive desulfurization technique. commercial activated carbon was loaded individually with copper oxide in the form of cu2o/ac. a comparison of the kinetic and isotherm models of the sorption of thiophene from model fuel was made at different operating conditions including adsorbent dose, initial thiophene concentration and contact time. various adsorption rate constants and isotherm parameters were calculated. results indicated that the desulfurization was enhanced when copper was loaded onto activated carbon surface. the highest desulfurization percent for cu2o/ac and origin ac at initial thiophene concentration of 500 ppm, adsorbent dose of 0.01 g/ml and equilibrium time of 5 hr were 87.4% and 53.4% respectively, for outlet concentration of 63 mg/l for copper oxide and 236 mg/l for original ac. generally, the percent removal of thiophene increases with the increase in adsorbent dose and decrease with increase in initial thiophene concentration. the present study was mainly focusing on the kinetics and adsorption isotherms aspect; adsorption kinetics of thiophene onto activated carbon supported cu2o adsorbent was closely represented by the second order kinetic model and freundlich isotherms well represented the equilibrium adsorption of thiophene from model fuel. key words: adsorptive desulfurization; activated carbon; copper; thiophene, kinetics, isotherms. introduction since most crude oils from different origins contains large amounts of sulfur and nitrogen compounds, many desulfurization techniques have been considered for sulfur-nitrogen removal; they are required for the purpose of protecting the environment against pollution by sulfurand nitrogen-oxide emanations (sox and nox). also, these contents cause catalyst poisoning as well as effecting vehicle engines [1] [2]. the removal of sulfur compounds from crude oil is basically carried out via catalytic hydrodesulfurization (hds) process. the hydrodesulfurization process considered being highly-costing process for the expensive conditions it requires, i.e., high temperature and pressure, and the high-cost catalysts it required. moreover, it does not fulfill the need to reach ultra-low sulfur university of baghdad college of engineering iraqi journal of chemical and petroleum engineering adsorption kinetic and isotherms studies of thiophene removal from model fuel on activated carbon supported copper oxide 84 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net content; thereby, other processes have been considered for such aim [3] [4]. oxidative desulfurization considered being an alternative process for sulfur removal aspect, in addition to many other processes such as extractive desulfurization, photochemical desulfurization, biodesulfuriation and the most important process which this study is considered to subject the light on is adsorptive desulfurization. the main advantages of adsorptive desulfurization process are the availability of the adsorbents used and it's low cost, and it does not require expensive conditions as in (hds) [5] [6]. many adsorbents are used for this purpose such as activated carbon, modified composite oxides, zeolites and many other porous material; moreover, metal oxides considered as good type of adsorbents used. the adsorbents used have a major effect for sulfur removal and to reach ultra-low sulfur content [7]. the present work employes three prepared adsorbents for thiophene removal from model fuel (thiophene in n-hexane) are tested. the adsorption kinetics to study the behavior of this process as well as to employs adsorption isotherms for the same concept. experimental 1. model fuel simulated model fuel consists of nhexane (c6h14, purity ≥ 99%, supplied from sigma-aldrich company, molecular weight, 86.18 g/mol; density, 0.871 gm/cm 3 at 16 o c; and boiling point, 74.1 o c) is mixed with different amounts of thiophene (c4h4s of 99.9% purity, supplied from fluka chemie ag, company, molecular weight, 84; density, 1.071 gm/cm 3 at 16 o c; and boiling point, 84.1 o c) as a sulfur source. 2. adsorbents activated carbon pellets (ac) (supplied from research products international corp. usa) of purity 99.9% was used as support without any heat or chemical pretreatment. the surface area (bet) and pore volume were tested using sorption of n2 and their values were 1066 (m 2 /g) and 0.65 cm 3 /g respectively. the ac pellets were milled and sieved to size range of (0.3-0.6) mm before impregnation. copper nitrate, cu(no3)2.3h2o, 97% purity supplied by fluka chemie ag company was used as copper precursor. 3. adsorbents preparation the adsorbent was prepared by incipient wetness impregnation technique where 40 gm activated carbon was impregnated under vacuum and room temperature with aqueous solution of cu(no3)2.3h2o. this was prepared previously by dissolving 12.3 g copper nitrate in 26 ml of distilled water to get 10 wt% metal loaded. the sample was left over 24 hr at the ambient conditions to load the largest amount of metal precursor. then the impregnated activated carbon sample was dried at 90 o c for 6 hr and calcined at 500 o c under vacuum for 3 hr. 4. desulfurization procedure the model oil used consisted of thiophene dissolved in n-hexane at different initial thiophene concentration. a series of experiments were carried out in batch operation in order to evaluate the influence of process parameters: initial thiophene concentration (250-2000 mg/l) and adsorbent dose (0.01-0.08 g/ml). all adsorption experiments were performed at room temperature and using 10 ml of liquid model fuel. http://www.iasj.net/ saad h. ammar and sama ali jaafar -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 85 in the first set of adsorption experiments, the contact time was varied from 15-360 min while fixing the other parameters initial thiophene concentration (cin) of 500 mg/l, and adsorbent dose of 0.01 g/ml. in the second set of experiments the effect of initial thiophene concentration was investigated by varying the initial concentration of sulfur as 250, 500, 1000 and 2000 mg/l and fixing the adsorbent dose at 0.01 g/ml and the contact time was equilibrium time (estimated from the first set results). finally, in the third set of experiments the effect of adsorbent dose (varied as 0.01, 0.02, 0.04 and 0.08 g/ml) was studied at constant contact time of equilibrium time and initial sulfur concentration of 500 mg/l. the desulfurization percentages were calculated as the ratio of the thiophene concentration that was adsorbed by the adsorbent to the thiophene concentration present initially in the model fuel according to equation bellow: …(1) the sulfur adsorption capacity (q) was calculated by using the following equation: … (2) where q is the amount of sulfur adsorbed (mg /g cat.), vsol is the volume of solution (l), cin, cout and ce are initial, outlet and equilibrium concentrations (mg /l), and m is the mass of adsorbent (g). the sulfur content in model fuel and real gasoil was determined by x-ray fluorescence in the petroleum research and development center/ministry of oil/baghdad by using horiba sulfur-in-oil analyzer type (slfa-2100). results and discussion 1. adsorbent characterization x-ray powder diffraction (xrd) was used to analyze the crystallinity and also to determine the oxidation phase of copper loaded onto activated carbon, using an xrd-6000 (bruker d2 phaser). according to thermal decomposition data of cu(no3)2.3h2o under vacuum [8] firstly, cu(no3)2.3h2o is melted at 115-155 °c, then converted to phase βcu2(oh)3no3 at 200-217 °c. by increasing the calcination temperature it is converted to cuo at 260–310 °c, finally cuo decomposes to cu2o at calcination temperature > 450 °c. figure 1 shows the xrd analysis of copper-impregnated ac sample. as shown in this figure, the diffraction peaks are at 2θ = 36°, 42.5°, 61° and 74° which indicate presence of cu2o crystals in ac. fig. 1: xrd analysis of cu2o-impregnated ac sample atomic absorption spectroscopy model (varian aa240 fs) was used for determination the total content of copper loaded onto activated carbon. the measured total content of copper was about 9.25 wt%. the bet surface area and the pore volume of the original activated carbon and impregnated activated carbon was determined using quanta chrome http://www.iasj.net/ adsorption kinetic and isotherms studies of thiophene removal from model fuel on activated carbon supported copper oxide 86 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net autosorb gas sorption system estimated from nitrogen adsorption and desorption. the surface area and pore volume of cu2o/ac were 995 m 2 /gm and 0.592 cm 3 /gm respectively compared with the origin ac which were 1066 m 2 /g and 0.65 cm 3 /g respectively. this indicates that the impregnating of 9.25 % copper oxide on ac did not have a big effect on the porosity of produced adsorbent. therefore, there are few carbon pores plugged due to metal impregnation compared with the original ac. 2. adsorption and kinetics studies the purpose of these studies is to determine the equilibrium time, mechanism of adsorption and to determine the rate-controlling step. the effect of contact time (0-6 hr) on thiophene adsorption from n-hexane as a model fuel onto cu2o/ac is shown in figure 2. it is clear that the rate of thiophene adsorption from model fuel was fast during the first 1 hr, this is clear due to the fact that a large number of unoccupied active sites are initially available for the adsorption and therefore higher driving force and fast mass transfer of thiophene take place. with the passage of adsorption time, the remaining unoccupied active sites are difficult to be taken due to repulsive forces between thiophene molecules on the adsorbent surface and in the liquid solution. in late stages, the adsorption of thiophene remains approximately constant and the difference between the uptake at 5 hr and 6 hr and was less than 0.5%. therefore, the approximation of steady state was specified and an equilibrium condition was considered to be 5 hr. maximum thiophene capacities were reported as 43.7 and 26.4 mg/g for cu2o/ac and ac respectively at initial thiophene concentration of 500 mg/l and adsorbent dose of 0.01 g/mg as shown in figure 2. based on the above results, the kinetic studies including. pseudo 1 st order (lagergren), pseudo 2 nd order, webermorris (intra-particle diffusion) and elovich kinetics models were performed on all thiophene adsorbent systems. a b fig. 2: outlet thiophene concentration (ct) (a) and uptake (qt) (b) vs. contact time of model fuel for cu2o/ac and original ac (initial thiophene concentration of 500 mg/l and adsorbent dose of 0.01 g/ml) a comparison of thiophene adsorption onto cu2o/ac and the original ac shows that the copper impregnation increases the thiophene uptake. the experimental results indicated that the thiophene removal was enhanced when copper was loaded onto ac surface about 65 % (at initial thiophene concentration of 500 mg/l and adsorbent dose of 0.01 g/ml). these results are in agreement with several previous studies such as [9] [10]. as suggested by seredych and bandosz [11], the enhancement in thiophenic compounds may take place due to the specific interactions between the supported metal species and thiophenic compounds molecules involving π0 200 400 600 0 1 2 3 4 5 6 7 c t (m g /l ) contact time (hr) cu2o/ac ac 0 10 20 30 40 50 0 2 4 6 8 q t (m g /g ) contact time (hr) cu2o/ac ac http://www.iasj.net/ saad h. ammar and sama ali jaafar -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 87 complexation and acid-base interactions in addition to the original dispersion interactions in ac micro and meso pores. for the kinetic study of model fuel desulfurization, various kinetic models had been proposed and used to determine the mechanism by which solute (thiophene) may be adsorbed. therefore, three kinetic models were used as follows: pseudo 1 st order model (lagergren model) the nonlinear and linear forms of lagergren model are [12]. …(3) …(4) where qt is the amount of sulfur adsorbed (mg sulfur/g cat.) at time t (min), qe the amount of sulfur adsorbed at equilibrium (mg sulfur/g cat.) and k1 is the equilibrium rate constant of pseudo first-order adsorption (min −1 ). pseudo2 nd -order model the pseudo second order model can be represented in the following forms [13]: …(5) …(6) where is the pseudo second order rate constant of adsorption (mg/g min). intra-particle diffusion model based on the theory of weber and morris [14], the adsorption kinetics was described according to the following model: √ …(7) where is the intra particle diffusion rate constant (mg/g min 1/2 ). elovich model the elovich model is mainly applied for chemical adsorption kinetics (chemisorption), it is predominately suitable for heterogeneous systems. this model can be expressed as follows [15]: …(8) where α = initial adsorption rate (mg/g min) and β is constant related to the surface coverage and the activation energy for chemical adsorption (g/mg). by assuming αβt >>> 1 the integration form of this model is: [16] …(9) equation 9 can be used to examine the validity of the elovich model to the kinetics of thiophene adsorption onto prepared catalysts by plotting qt vs. ln(t). figures 3a, 3b, 3c and 3d. show the application of the above kinetic models by plotting log (qe-qt) vs. t, (t/qt) vs. t, qt vs. √ and qt vs. ln(t) respectively for cu2o/ac adsorbent. to determine the extent of approval of each kinetic model, the coefficient correlation (r 2 ) was calculated from these plots. the greatest r 2 value indicates the applicability of the model. different adsorption rate constants including experimental and calculated qe values are summarized in table 1. it can be concluded from this table and also from figures 3a., 3c. and 3d. that the results did not obeys the 1 st order, diffusion kinetic or elovich models due to relatively low values of r 2 . for 1 st order model, a large variation was noticed between the experimental (qe exp.) and calculated (qe cal.) equilibrium uptake values. in case of 2 nd order model, a linear relationship was noted between (t/qt) and t over all the entire adsorption period as shown http://www.iasj.net/ adsorption kinetic and isotherms studies of thiophene removal from model fuel on activated carbon supported copper oxide 88 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net in figure 3b. the experimental and calculated qe values from the pseudo 2 nd order kinetic model are close to each other and the calculated correlation-coefficients (r 2 ) are closer to unity for pseudo 2 nd order kinetics than that for other models. based on these results, the thiophene adsorption over cu2o/ac can be represented more suitably by the pseudo 2 nd order kinetic model. a b c d fig. 3: plot of pseudo 1 st order (a), pseudo 2 nd order (b), intra particle diffusion (c) and elovich (d) kinetic models for thiophene adsorption from model fuel at initial thiophene concentration of 500 mg/l and adsorbent dose of 0.01 g/ml table 1: adsorption kinetic parameters for the desulfurization of model fuel (cin=500 mg/l, catalyst concentration = 0.01 g/ml, vsol. = 10 ml, mcat = 0.1 g) adsorption model parameters value cu2o/ac pseudo 1 st order model k1 (min -1 ) 0.008 qe (mg/g) exp 43.7 qe (mg/g) cal 21.327 r 2 0.708 pseudo2 nd order model (mg/g min) 0.001735 qe (mg/g) exp 43.7 qe (mg/g) cal 45.45 r 2 0.995 diffusion model √ (min -1 ) 1.866 i1 (mg/g) 0 i2 (mg/g) 13.23 r 2 0.757 elovich model α (mg/g min) 26.17 β (g/mg) 0.166 r 2 0.9246 3. effect of initial thiophene concentration figures 4a and 4b show the effect of initial thiophene concentration, cin (from 250 to 2000 mg/l) on the equilibrium thiophene concentration (ce), and desulfurization percentage. figure 5 shows the adsorption isotherms (equilibrium uptake vs. equilibrium thiophene concentration) of thiophene onto cu2o/ac of model fuel at constant adsorbent dose of 0.01 g/ml and equilibrium time of 5 hr. the results represented in figures 4a and4b, show that the desulfurization percentage decreases (and the equilibrium thiophene concentration increases) with increasing initial thiophene concentration. this can be attributable to that all the adsorbent have a limited number of active sites on its surface, which becomes saturated at a certain concentration. 0 1 2 3 4 0 100 200 300 ln (q e -q t) t (min) cu2o/a c 0 2 4 6 8 10 0 100 200 300 400 (t /q t) t (min) cu2o/ac 0 10 20 30 40 50 0 5 10 15 20 q t (t)^0.5 cu2o/a c 0 10 20 30 40 50 0 2 4 6 8 q t ln(t) cu2o/ac http://www.iasj.net/ saad h. ammar and sama ali jaafar -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 89 a b fig. 4: effect of initial thiophene concentration on thiophene equilibrium concentration (a), and desulfurization (b) at adsorbent dose of 0.01 g/ml and equilibrium time of 5 hr fig. 5: equilibrium uptake of thiophene adsorption from model fuel onto cu2o/ac at different initial thiophene concentration (adsorbent dose of 0.01 g/ml and equilibrium time of 5 hr) 4. effect of adsorbent dose figure 6 shows the effect of adsorbent dose (g/ml) on the desulfurization percentage of thiophene onto cu2o/ac at constant initial thiophene concentration of 500 mg/l and equilibrium time of 5 hr. the increase in adsorption percentage with adsorbent dose can be attributed to the availability of greater surface area and therefore a larger number of adsorption active sites. when using low sorbent dose (i.e. available surface area is less than optimum or required), the sorbent surface becomes saturated with thiophene and therefore the large concentration of residual thiophene is remained in the solution. on continuous increasing in sorbent dose, more surface area, and active sitesleads to increase in thiophene removal because the thiophene uptake is increased by a more available sorbent. when using adsorbent dose greater than required, the percent removal of thiophene becomes nearly constant. figure 7 shows the equilibrium uptake vs. equilibrium thiophene concentration of thiophene onto cu2o/ac at different adsorbent dose. a b fig. 6: effect of adsorbent dose (g/ml) on thiophene equilibrium concentration, ce (a) and desulfurization% (b) at initial thiophene concentration of 500 mg/l and equilibrium time of 5 hr fig. 7: equilibrium uptake of thiophene adsorption from model fuel cu2o/ac at different adsorbent dose at initial thiophene concentration of 500 mg/l and equilibrium time of 5 hr 0 50 100 150 200 250 300 350 0 1000 2000 3000 c e ( m g /l ) cin (mg/l) cu2o/ac 70 75 80 85 90 95 0 500 1000 1500 2000 2500 d e su lf u ri za ti o n ( % ) cin (mg/l) cu2o-ac 0 50 100 150 200 0 100 200 300 400 q e ( m g /g ) ce (mg/l) cu2o/ac 0 20 40 60 80 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 c e ( m g /l ) catalyst concentration (g/ml) cu2o/ac 50 60 70 80 90 100 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 d e su lf u ri za ti o n % catalyst concentration (mg/ml) cu2o-ac 0 10 20 30 40 50 0 20 40 60 80 q e ( m g /g ) ce (mg/l) cu2o/ac http://www.iasj.net/ adsorption kinetic and isotherms studies of thiophene removal from model fuel on activated carbon supported copper oxide 90 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net adsorption isotherms the experimental equilibrium adsorption data of thiophene adsorption onto cu2o/ac have been analyzed by using freundlich and langmuir isotherms at different initial thiophene concentration and adsorbent dose as shown in figures 8 and 9. the non-linear form of langmuir isotherm model is given by the following equation: …(10) where 𝐶 is the equilibrium concentration of thiophene (mg/l), is equilibrium adsorption capacity of thiophene adsorbed per unit mass of the adsorbent (mg/g), qo is the maximum monolayer-coverage amount of thiophene adsorbed per unit mass of the adsorbent given in (mg/g), and 𝐾𝐿 is the langmuir isotherm constant (l/mg). langmuir adsorption isotherm assumes formation and attachment of a monolayer of adsorbate molecules on a specific number of sites on the surface of the solid adsorbents [17]. freundlich adsorption isotherm is used to characterize the multilayer adsorption for the heterogeneous surfaces. the freundlich model in an exponential form is given by the following relation [18]: 𝐾 𝐶 …(11) where 𝐾 is the freundlich isotherm constant (mg/g) and n is the adsorption intensity. the langmuir isotherm parameters qo and 𝐾 , the correlation coefficient (r 2 ), the freundlich isotherm constants 𝐾 , n and coefficient-correlation (r 2 ) were determined by linearized-form regression are shown in tables 2 and 3. the experimental data fitting to the langmuir and freundlich isotherms are shown in figures 8 and 9. results indicated that the adsorption situation for thiophene adsorption from model fuel is described better by freundlich isotherm model. the results areconfirmed by the calculated correlation coefficient (r 2 ) between the experimental and calculated values for the two isotherm models. therefore, by using freundlich isotherm model, results showed that the (r 2 ) were 0.9971 for initial concentration study and 0.9327 for adsorbent dose study. figure 10 shows the comparison of experimental, langmuir and freundlich adsorption isotherms at different initial thiophene and adsorbent dose. fig. 8: fitting of langmuir (top) and freundlich (bottom) isotherms at different initial thiophene concentration on cu2o/ac adsorbent table 2: langmuir and freundlich parameters for the desulfurization of model fuel isotherm model parameters value cu2o/ac langmuir 𝐾 𝐶 𝐾 𝐶 qo (mg/g) 263.15 𝐾 (l/mg) 0.00366 r 2 0.9886 freundlich 𝐾 𝐶 𝐾 (mg/g) 1.468 n 1.197 r 2 0.9971 y = 1.0376x + 0.0038 r² = 0.9886 0 0.01 0.02 0.03 0.04 0.05 0 0.02 0.04 0.06 1 /q e 1/ce y = 0.8354x + 0.3844 r² = 0.9971 0 1 2 3 4 5 6 0 2 4 6 ln (q e ) ln(ce) http://www.iasj.net/ saad h. ammar and sama ali jaafar -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 91 fig. 9: fitting of langmuir (top) and freundlich (bottom) isotherms at different initial adsorbent dose on zno/ac (a), cu2o/ac (b) and nio/ac (c) table 3: langmuir and freundlich parameters for the desulfurization of model fuel isotherm model parameters value cu2o/ac langmuir 𝐾 𝐶 𝐾 𝐶 qo (mg/g) 333.34 𝐾 (l/mg) 0.00152 r 2 0.9755 freundlich 𝐾 𝐶 𝐾 (mg/g) 0.364 n 0.915 r 2 0.9327 fig. 10: experimental, langmuir and freundlich adsorption isotherms at different initial thiophene (top) and adsorbent dose (bottom) conclusion adsorptive desulfurization of the model fuel was performed using cu2o/ac prepared by using impregnation method. thiophene removal capacity, adsorption kinetics and adsorption isotherms were studied in batch operation. the following conclusions can be summarized from the presented study:  using activated carbon in adsorptive desulfurization method for sulfur compounds removal from liquid fuels was very efficient especially when loaded with metal oxides. the experimental results indicate that the thiophene uptake was enhanced when copper loaded onto activated carbon surface.  the equilibrium concentration was established after 5-6 hours, of 63 mg/l for cu2o and 236 mg/l for original ac.  in general, the percent removal of thiophene increases with the increase in adsorbent dose and decrease with increase in initial thiophene concentration.  the adsorption kinetics of thiophene onto activated carbon supported cu2o sorbent could be closely represented by the 2 nd order kinetic model.  freundlich isotherms in general well represent the equilibrium adsorption of thiophene from model fuel. nomenclatures a= initial adsorption rate (mg/g.min) ac= activated carbon b= constant related to the surface coverage and the activation energy for chemical adsorption (g/mg) ce= equilibrium concentration (mg/l) cin= initial concentration (mg/l) cout= final concentration (mg/l) k1= equilibrium rate constant of pseudo first-order adsorption (min -1 ) y = 1.973x + 0.003 r² = 0.9755 0 0.05 0.1 0.15 0.2 0 0.05 0.1 1 /q e 1/ce y = 1.093x 1.0107 r² = 0.9327 0 1 2 3 4 0 2 4 6 ln (q e ) ln(ce) 0 50 100 150 200 10 110 210 310 q e ( m g /g ) ce (mg/l) experimental langmuir freundlich 0 10 20 30 40 50 0 20 40 60 80 q e ( m g /g ) ce (mg/l) experimental langmuir freundlich http://www.iasj.net/ adsorption kinetic and isotherms studies of thiophene removal from model fuel on activated carbon supported copper oxide 92 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net = pseudo second order rate constant of adsorption (mg/g.min) = intra particle diffusion rate constant (mg/g.min -1 ) 𝐾 = freundlich isotherm constant (mg/g) 𝐾 = langmuir isotherm constant (l/mg) mcat.= the mass of the catalyst (g) q =the amount of sulfur adsorbed (mg/g) qo=the maximum monolayer-coverage amount of thiophene adsorbed per unit mass of the adsorbent (mg/g) qe =the amount of sulfur adsorbed at equilibrium (mg/g) qt =the amount of sulfur adsorbed at time (t) (mg/g) r 2 =the coefficient of correlation t =time (min) v sol =the volume of the solution (l) α = initial adsorption rate (mg/g.min) β= constant related to the surface coverage and the activation energy for chemical adsorption (g/mg) references 1. kim, j. h., ma, x., zhou, a., and song, c. (2006). ultra-deep desulfurization and denitrogenation of diesel fuel by selective adsorption over three different adsorbents: a study on adsorptive. 2. mužic, m., and sertić-bionda, k. (2013). alternative processes for removing organic sulfur compounds from petroleum fractions. chemical and biochemical engineering quarterly, 27 (1), 101-108. 3. campos‐martin, j. m., capel‐ sanchez, m. d. c., perez‐presas, p., and fierro, j. l. g. (2010). oxidative processes of desulfurization of liquid fuels. journal of chemical technology and biotechnology, 85 (7), 879-890. 4. soleimani, m., bassi, a., and margaritis, a. (2007). biodesulfurization of refractory fossil fuels. biotechnology advances, 25 (6), 570-596 5. xiaolin, t., and le zheting, s. l. (2011). deep desulfurization via adsorption by silver modified bentonite. china petroleum processing and petrochemical technology, 13, 16-20. 6. ahmad, w., ahmad, i., ishaq, m., and ihsan, k. (2014). adsorptive desulfurization of kerosene and diesel oil by zn impregnated montmorollonite clay. arabian journal of chemistry. 7. adeyi, a. a., and aberuagba, f. (2012). comparative analysis of adsorptive desulphurization of crude oil by manganese dioxide and zinc oxide. research journal of chemical sciences, 2 (8), 14-20. 8. morozov, i. v., znamenkov, k. o., korenev, y. m., and shlyakhtin, o. a. (2003). thermal decomposition of cu (no 3) 2· 3h 2 o at reduced pressures. thermochimicaacta, 403 (2), 173-179. 9. moosavi, e. s., dastgheib, s. a., and karimzadeh, r. (2012). adsorption of thiophenic compounds from model diesel fuel using copper and nickel impregnated activated carbons. energies, 5 (10), 42334250. 10. seredych, m., and bandosz, t. j. (2010). adsorption of dibenzothiophenes on activated carbons with copper and iron deposited on their surfaces. fuel processing technology, 91 (6), 693701. 11. seredych, m., and bandosz, t. j. (2011). investigation of the enhancing effects of sulfur and/or oxygen functional groups of nanoporous carbons on adsorption http://www.iasj.net/ saad h. ammar and sama ali jaafar -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 93 of dibenzothiophenes. carbon, 49 (4), 1216-1224. 12. lagergren, s. (1898). about the theory of so called adsorption of solute substances. ksver veterskapsakad handl, 24, 1-6. 13. ho, y.s.; and mckay, g. (1999). pseudo-second-order model for sorption processes. process biochemistry, 34 (5), 451-465. 14. weber, w.j.; asce, jr j.m.; and morris, j.c. (1963) kinetics of adsorption on carbon from solutions. journal of sanitary engineering division of american society of civil engineering, 89, 3160. organic sulfur compounds in. 15. low, m. j. d. (1960). kinetics of chemisorption of gases on solids. chemical reviews, 60 (3), 267-312. 16. chien, s. h., and clayton, w. r. (1980). application of elovich equation to the kinetics of phosphate release and sorption in soils. soil science society of america journal, 44 (2), 265-268. 17. dada, a. o., olalekan, a. p., olatunya, a. m., and dada, o. (2012). langmuir, freundlich, temkin and dubinin–radushkevich isotherms studies of equilibrium sorption of zn2+ unto phosphoric acid modified rice husk. journal of applied chemistry, 3 (1), 38-45.. 18. umpleby, r. j., baxter, s. c., bode, m., berch, j. k., shah, r. n., and shimizu, k. d. (2001). application of the freundlich adsorption isotherm in the characterization of molecularly imprinted polymers. analytica chimica acta, 435 (1), 35-42. http://www.iasj.net/ available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.21 no.1 (march 2020) 33 – 38 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: mohammed najeeb , email: mo6613979@gmail.com, name: fadhil sarhan kadhim, email: fadhilkadhim47@yahoo.com, name: ghazwan noori saed , email: ghazwanj@gmail.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. using different methods to predict oil in place in mishrif formation / amara oil field mohammed najeeb a , fadhil sarhan kadhim a and ghazwan noori saed b a university of technology / petroleum technology department b university of kufa / chemical engineering department abstract the reserve estimation process is continuous during the life of the field due to risk and inaccuracy that are considered an endemic problem thereby must be studied. furthermore, the truth and properly defined hydrocarbon content can be identified just only at the field depletion. as a result, reserve estimation challenge is a function of time and available data. reserve estimation can be divided into five types: analogy, volumetric, decline curve analysis, material balance and reservoir simulation, each of them differs from another to the kind of data required. the choice of the suitable and appropriate method relies on reservoir maturity, heterogeneity in the reservoir and data acquisition required. in this research, three types of reserve estimation used for the mishrif formation / amara oil field volumetric approach in mathematic formula (deterministic side) and monte carlo simulation technique (probabilistic side), material balance equation identified by mbal software and reservoir simulation adopted by petrel software geological model. the results from these three methods were applied by the volumetric method in the deterministic side equal to (2.25 mmmstb) and probabilistic side equal to (1.24, 2.22, 3.55) mmmstb p90, p50, p10 respectively. ooip was determined by mbal software equal to (2.82 mmmstb). finally, the volume calculation of ooip by using the petrel static model was (1.92 mmmstb). the percentage error between material balance and the volumetric equation was equal to 20% while the percentage error between the volumetric method and petrel software was 17%. keywords: ooip, reserve estimation, monte carlo simulation, hiip received on 25/06/2019, accepted on 22/09/2019, published on 30/03/0220 https://doi.org/10.31699/ijcpe.2020.1.5 1introduction the amount of crude oil that exists in the subsurface related to the deposition of organic matter which in turn attributed to the sediments. the type and amount of hydrocarbon generated in the trap depend on several factors: quality of organic matter in the sediments, the abundance of organic matter, the area and size of organic matter was matured during burial and also circumstances of the environment (pressure and temperature) in which organic matter accumulated ‎[1]. the reservoir engineer is under the challenges to accomplish accurate estimation of hydrocarbon contents that existed in the reservoir and evaluate quantitatively recoverable hydrocarbon from a field, zone or area. petroleum engineering science contains one of the highest uncertainty problems because it deals with invisible or not touchable subjects. along with this matter, all of the data used in the estimation process is burdened with uncertainty problem and this problem regarded endemic problem ‎[2]. risks and uncertainties play a curial role along with alltime phases of field life. specifically, in the early life of the field when uncertainty presence is quite major thereby, erratic quantifying of uncertainty leads to underestimation or underestimation of reserves ‎[2]. therefore, the level of uncertainty is impacted by the following factors: ‎[3] 1. reservoir type 2. source of the reservoir drive mechanism 3. amount and accuracy data used 4. available technology and 5. knowledge and experience of the estimator. however, the uncertainty problem is decreased with time until the field reaches abandonment point. consequently, reserve estimation is a function of time and data as shown in fig. 1. fig. 1. changes in reserve estimation along time and suitable method ‎[4] https://doi.org/10.31699/ijcpe.2020.1.5 m. najeeb et. al. / iraqi journal of chemical and petroleum engineering 21,1 (2020) 33 38 43 fundamentally, the main objective of this work is carried out to find out the appropriate and consistent method for hydrocarbon in place estimation pertinent taking in the account easily using computers and the petroleum software which is helps us to achieve accurate reserve estimation. in this paper, three major approaches; volumetric, material balance calculation and reservoir simulation technique to determine volume of oil in place and compare stock tank oil in place (stoip) results obtained for analyses of possible variation in estimation process this comparison can be lead to a reasonable and reliable estimate of oil reserves according to reservoir characteristics. 1.1. reserves and resources definition the diagram in fig. 2 illustrates the classification and categorization of reserves and petroleum resources systems according to the petroleum resources and management system (prms) ‎[5] definitions established by spe/ wpc /seg /spee/ aapg/ spwla/ eaga. fig. 2. recourses classification systems framework ‎[5] the terms "reserve" and "resource" have a specific meaning in petroleum qualification and therefore distinguish between them are essential. reserves in the prms definition are "these amounts of hydrocarbon can be obtained from commercial processes after implementation of these projects in order to identified accumulations under the specific date and defined conditions". reserves can be classified into discovered, recoverable, commercial, and remaining depends on projects applied. also, reserves can be subclassified according to the level of uncertainty into proved, probable and possible reserves. proved reserves in prms definition are "these amounts of hydrocarbon can be estimated with appropriate certainty under available data that are related to the reservoir has commercial benefits". probable reserves in prms definition are "these extra reserves are referred to less than proved reserves but increasingly accurate than possible reserves". possible reserves in prms definition are "these more reserves are considered are less recoverable than probable reserves". on the other side, resources in the prms definition are "all amounts of hydrocarbon normally happening in the subsurface formations, discovered and undiscovered (recoverable and unrecoverable), as well as these amounts already produced. at last, it contains all kinds of petroleum regarded conventional or unconventional". in addition, the resources can be sub-classified into two kinds: contingent resources and prospective resources. contingent resources in the prms definition are "these amounts of hydrocarbon are computed, at a specific date, to be possibly recoverable from identified accumulations, by applying projects that not regarded inside commercial process because of more than contingencies". prospective resources in the prms definition are "these amounts of hydrocarbon determined, at a particular date, as possibly taken from unknown accumulations". if the initial petroleum in – place (ipip) is divided in reserves, this terminology can be classified as 1p (proved), 2p (proved and probable), and 3p (proved, probable and possible) reserves, the contingent resources are classified into 1c, 2c, and 3c, while the term 1u, 2u, and 3u are used for perspective resources. hence, reserves compose subdivision of resources as shown in fig. 3 below: fig. 3. resources classification tree ‎[6] 1.2. reserves estimation framework reserves estimation procedure in petroleum basin involves several aspects summarized below: ‎ [7] 1) seismic surveys, to identify subsurface structures comprising hydrocarbon accumulation. 2) drilling exploration wells, to discover subsurface circumstances (geologically and petro – physically). 3) valuation of hydrocarbon accumulations, which involves; a) determine amounts of hydrocarbon trap in the discovered structure area. b) fluid properties ( to identify physical characteristics for oil, water, and gas formation) c) core analysis, to study different petrophysical d) parameters for reservoir rocks. finally, reserves estimation to calculate hydrocarbon content in place existed in the reservoir. m. najeeb et. al. / iraqi journal of chemical and petroleum engineering 21,1 (2020) 33 38 43 1.3. reserves estimations methods reserves estimation methods can be broadly classified in to: [8] 1analogy method 2volumetric method 3material balance calculations 4decline curve analysis 5reservoir simulation method reserves estimation can be categorized relating to pre and post-production stages i.e. (static and dynamic). the static methods indicate to analogy and volumetric calculation which used before the start of production in the reservoir and generally used geologic and engineering data while dynamic methods involved performance techniques applied after production started in the field and typically need production data and pressure of wells. fig. 4 below illustrates reserves estimation methods. fig. 4. reserves estimation methods [8] 1.4. reservoir description amara oil field is located at southeastern iraq in maysan governorate, the distance of around 10 km southeastern of amara city. it is surrounded by different oil fields about 25 km east of the al-rafedain field, and 30 km southeastern al kumait field. the field lies on the unstable shelf at the mesopotamian basin at coordinate (utm38r 694628.72me, 3520629.67mn) and (706121.34me, 3516859.11mn). [9] as shown in fig. 5 below. fig. 5. location of amara oil field ‎[9] 2methodology in this study, three methods of hydrocarbon initially in place (hiip) are used, the result obtained with the select most suitable and confidence method according to reservoir characteristics for mishrif formation / amara oil field as a case study as follow: in this study, three methods of hydrocarbon initially in place (hiip) are used, the result obtained with the select most suitable and confidence method according to reservoir characteristics for mishrif formation / amara oil field as a case study as follow: 1volumetric method: the conventional volumetric equation is: stooip = 7758*a*h*ø*(1-swi) / boi (1) it is obvious, the volumetric equation based on area, net pay, effective porosity, water saturation, and formation volume factor. deterministic and stochastic approach used to estimate hydrocarbon amount. in deterministic approach single best value input to obtain one value for reserve while, in probabilistic approach involves the following procedure: firstly input all reservoir variables as max, min, mode then select the suitable distribution for each input parameter such triangular, rectangle and normal after that run monte carlo simulation (mcs) by model risk analysis to obtain pessimistic, most likely and optimistic reserve value (p90, p50, p10) and quantify error percentage for each parameter by tornado plot. 2material balance equation: the material balance equation has been considered for many years as a basic tool for reservoir engineers for predicting and interpreting reservoir performance. the material balance (mb) equation can be used to calculate hydrocarbon content (n), water influx (we), predict future reservoir performance, forecast reservoir pressure, and predict ultimate hydrocarbon recovery under many types of the drive mechanism. m initial + m add – m removed = m remaining (2) one of the intrinsic principles used in petroleum engineering is the law of conservation of mass. the application of this law to a petroleum reservoir is known as the "material balance equation". it is necessary for reservoir engineers to understand realistically the material balance during its depletion history. mbal software was adapted to accomplish material balance equation calculations. m. najeeb et. al. / iraqi journal of chemical and petroleum engineering 21,1 (2020) 33 38 43 3reservoir simulation: the term "reservoir simulation" commonly refers to the building and execution of a particular model that represents the actual reservoir behavior in other words, it is a tool used to mirrors the activities that happen in producing a reservoir. this process includes the integration of production data, petrophysics, pvt data, rock and fluid properties, and geology…..etc. so on to obtain the best view of reservoir behavior. the model may be a mathematical or physical model subject to limitations and conditions depending on the nature of the reservoir. petrel software was adapted to establish the geological model to reach volume calculation step after entered all wellhead, well tops and contour map to construct structural model for each unit of mishrif then upscaling all well logs by arithmetic average and division each layer according to hydrocarbon accumulation after that distribution all petrophysical parameters by sequential gaussian distribution for each zone of mishrif to create property modeling finally, estimate original oil in place (ooip) by simulator run. 3results and discussion volumetric equation method applied by using a deterministic and stochastic approach. in deterministic method, all volumetric equation parameters calculated by ip software of detected depth of mishrif formation / amara oil field (2840-3600) m of well (am5, am6, am7, am8, am10, am11, am12, am13, am14, am15) as shown in table 1 the resulted ooip was while, the probabilistic manner, monte carlo simulation (mcs) adapted by model risk analysis software after inputs each of static volumetric parameters in max, min, and average or mode values as shown in table 2 then select triangular distribution function for each of them for (10000 samples) number of iterations to generate proved (p90), proved plus probable (p50) proved plus probable plus possible (p10) was (4201, 2.22, 5233) mmmstb respectively the obtained result by volumetric equation equal mode or p50 it is an indication the estimation process was true. the material balance equation was estimated by mbal software after inputs all reservoir properties: tank parameters, water influx, rock compressibility, relative permeability, and production history the resultant ooip is equal (2.82 mmmstb) fig. 7 illustrates havlena – odeh approach x-axis was f / et and the y-axis was we / et. finally, petrel static model established by constructing a structural contour map for each unit of mishrif formation then imported well logs information by ip software then upscaling, layering, and distribution reservoir properties by sequential gaussian distribution (sgd) statistical method to accomplish volume calculation step the obtained totally hydrocarbon accumulation for all zone of mishrif was (1.92 mmmstb). table 1. static volumetric parameters well net thickness (m) av phi av am-5 91.91 0.22833333 0.284333333 am-6 71.08 0.1885 0.283 am-7 13.95 0.167 0.337 am-8 44.08 0.204 0.289 am-10 55.17 0.33016667 0.324 am-11 89.55 0.1935 0.2445 am-12 55.62 0.18825 0.27325 am-13 126.41 0.187 0.274 am-14 39.26 0.1665 0.235 am-15 33.48 0.1395 0.279 73.37875 0.23165625 0.318010417 table 2. uncertainty volumetric data net thickness (m.) av phi av area (acre) (bbl./stb) min 13.95 0.1395 0.235 10670 1.35 mode 71.635 0.210781 0.275885 11000 1.38 max 126.41 0.330167 0.337 11330 1.41 fig. 6. tornado plot for sensitivity analysis table 3. comparisons of ooip by three methods formation volumetric method mbal software petrel software mishrif 2.25 2.82 mmm stb 1.92 mmm stb m. najeeb et. al. / iraqi journal of chemical and petroleum engineering 21,1 (2020) 33 38 43 fig. 7. havlena – odeh method of amara oil field 4conclusion according to this study, the main conclusion is: the most reliable and reasonable method of original oil in place (ooip) estimation in the mishrif formation / amara oil field was the reservoir geological model which was (1.92 mmmstb). because was used well logs data resulted from ip software, structural model of each unit of mishrif reservoir (ma, mb11, mb12, mb13, mb21, mc1, and mc2), scale-up well logs, make horizons, petrophysical distribution, detect oil-water contact level to obtain the volume calculation result of ooip. hence, the ma unit represents the best zone in the mishrif formation because it contains the biggest amount of hydrocarbon accumulation of (1.53 mmmstb). nomenclature prms: petroleum resources and management system spe: society of petroleum engineering wpc: world petroleum council seg: society of exploration geophysicists spee: society of /petroleum evaluation engineers aapg: association of petroleum geologists spwla: society of petrophysicists and well log analysis eaga: european association of geoscientists and engineers a: area (acre) am: amara b: billon boi: initial oil formation volume factor bstb: billon stock tank barrel h: net pay (ft.) hiip: hydrocarbon initially in place ip: interactive petrophysics mb: material balance mcs: monte carlo simulation ø: effective porosity (percent) ooip: original oil in place p10: 10% confidence 90% error p50: 50% confidence 50% error p90: 90% confidence 10% error sw: water saturation (percent) references [1] igbokwe and l. chidozie, "comparative analysis of reserve estimation using volumetric method and mbal on niger delta oil fields", university of technology of owerri, published thesis, nigeria, 2011. [2] maksim y. nazarenko, "probabilistic production forecasting and reserves estimation in water flooded oil reservoirs", texas a&m university, published thesis, usa. 2016. [3] robert kosova, adrian naco and irakli prifti, "deterministic and stochastic methods of oil field reserves estimation: a case study from ka. oil field", interdisplinary journal of research and development, vol. (iv), no.2, 2017, pp226-231. [4] petroleum resources management system (prms) , society of petroleum engineers (spe), american association of petroleum geologists (aapg), world petroleum council (wpc), society of petroleum evaluation engineers (spee), society of exploration geophysicists (seg), society of petro physicists and well log analysts (spwla), european association of geoscientists & engineers (eage). 2017. [5] kosova robert, shehu valentina, naço adrian, xhafaj evgjeni, stana alma, ymeri agim, "monte carlo simulation for estimating geologic oil reserves. a case study kuçova oil field in albania" 2015, pp. 20-25 [6] p.f. worthington, "reserves—getting it right", international petroleum technology conference, iptc 10809, doha, qatar. 2005. [7] hugo araujo and aquiles rattia, "reserves follow-up using an integrated deterministic-probabilistic approach", spe 143843, colorado, usa. 2011. [8] buraq adnan al-baldawi, "applying the cluster analysis technique in logfacies determination for mishrif formation, amara oil field, south eastern iraq" , arabian journal of geosciences, volume 8, issue 6, 2014, pp3767-3776. [9] jawad k. radhy albahadily and medhat e. nasser, "petrophysical properties and reservoir modeling of mishrif formation at amara oil field, southeast iraq", iraqi journal of science, vol. 58, no.3a, 2017, pp1262-1272. http://futospace.futo.edu.ng/handle/123456789/1668 http://futospace.futo.edu.ng/handle/123456789/1668 http://futospace.futo.edu.ng/handle/123456789/1668 http://futospace.futo.edu.ng/handle/123456789/1668 https://oaktrust.library.tamu.edu/handle/1969.1/157084 https://oaktrust.library.tamu.edu/handle/1969.1/157084 https://oaktrust.library.tamu.edu/handle/1969.1/157084 https://oaktrust.library.tamu.edu/handle/1969.1/157084 https://www.researchgate.net/profile/irakli_prifti/publication/316103542_deterministic_and_stochastic_methods_of_oilfield_reserves_estimation_a_case_study_from_ka_oilfield/links/58f08c77aca27289c2100815/deterministic-and-stochastic-methods-of-oilfield-reserves-estimation-a-case-study-from-ka-oilfield.pdf https://www.researchgate.net/profile/irakli_prifti/publication/316103542_deterministic_and_stochastic_methods_of_oilfield_reserves_estimation_a_case_study_from_ka_oilfield/links/58f08c77aca27289c2100815/deterministic-and-stochastic-methods-of-oilfield-reserves-estimation-a-case-study-from-ka-oilfield.pdf https://www.researchgate.net/profile/irakli_prifti/publication/316103542_deterministic_and_stochastic_methods_of_oilfield_reserves_estimation_a_case_study_from_ka_oilfield/links/58f08c77aca27289c2100815/deterministic-and-stochastic-methods-of-oilfield-reserves-estimation-a-case-study-from-ka-oilfield.pdf https://www.researchgate.net/profile/irakli_prifti/publication/316103542_deterministic_and_stochastic_methods_of_oilfield_reserves_estimation_a_case_study_from_ka_oilfield/links/58f08c77aca27289c2100815/deterministic-and-stochastic-methods-of-oilfield-reserves-estimation-a-case-study-from-ka-oilfield.pdf https://www.researchgate.net/profile/irakli_prifti/publication/316103542_deterministic_and_stochastic_methods_of_oilfield_reserves_estimation_a_case_study_from_ka_oilfield/links/58f08c77aca27289c2100815/deterministic-and-stochastic-methods-of-oilfield-reserves-estimation-a-case-study-from-ka-oilfield.pdf https://www.onepetro.org/general/spe-194053-wp https://www.onepetro.org/general/spe-194053-wp https://www.onepetro.org/general/spe-194053-wp https://www.onepetro.org/general/spe-194053-wp https://www.onepetro.org/general/spe-194053-wp https://www.onepetro.org/general/spe-194053-wp https://www.onepetro.org/general/spe-194053-wp https://www.onepetro.org/general/spe-194053-wp http://biozoojournals.ro/oscsn/cont/31_2/03_kosova.pdf http://biozoojournals.ro/oscsn/cont/31_2/03_kosova.pdf http://biozoojournals.ro/oscsn/cont/31_2/03_kosova.pdf http://biozoojournals.ro/oscsn/cont/31_2/03_kosova.pdf http://biozoojournals.ro/oscsn/cont/31_2/03_kosova.pdf https://www.onepetro.org/conference-paper/iptc-10809-ms https://www.onepetro.org/conference-paper/iptc-10809-ms https://www.onepetro.org/conference-paper/iptc-10809-ms https://www.onepetro.org/conference-paper/spe-143843-ms https://www.onepetro.org/conference-paper/spe-143843-ms https://www.onepetro.org/conference-paper/spe-143843-ms https://link.springer.com/article/10.1007/s12517-014-1490-z https://link.springer.com/article/10.1007/s12517-014-1490-z https://link.springer.com/article/10.1007/s12517-014-1490-z https://link.springer.com/article/10.1007/s12517-014-1490-z https://link.springer.com/article/10.1007/s12517-014-1490-z https://www.iasj.net/iasj?func=article&aid=129379 https://www.iasj.net/iasj?func=article&aid=129379 https://www.iasj.net/iasj?func=article&aid=129379 https://www.iasj.net/iasj?func=article&aid=129379 https://www.iasj.net/iasj?func=article&aid=129379 m. najeeb et. al. / iraqi journal of chemical and petroleum engineering 21,1 (2020) 33 38 43 استخدام طرق مختمفة لمتنبؤ بالخزين النفطي االصمي في تكوين مشرف / حقل عمارة النفطي 2و غزوان نوري 1فاضل سرحان ,1محمد نجيب الجامعة التكنولوجية, قسم هندسة النفط1 جامعة الكوفة, قسم الهندسة الكيمياوية2 الخالصة عممية تقدير االحتياطي مستمرة خالل حياة الحقل بسبب المخاطر وعدم الدقة التي تعتبر مشكمة متوطنة تعريف المحتوى الهيدروكاربوني الحقيقي والمعروف بشكل وبالتالي يجب دراستها. عالوة عمى ذلك ، يمكن صحيح فقط عند نفاد الحقل. ونتيجة لذلك ، فإن التحدي المتمثل في تقدير االحتياطي هو دالة الوقت والبيانات . يمكن تقسيم تقدير االحتياطي إلى خمسة أنواع من القياس: التشابة ، الحجمي ، تحميل منحنى المتوفرة يعتمد توازن المواد ومحاكاة المكمن ، يختمف كل منهما من نوع آلخر عن نوع البيانات المطموبة. االنحدار ، اختيار الطريقة المناسبة والمالئمة عمى نضج المكمن وعدم التجانس في المكمن والحصول عمى البيانات تخدمة في تكوين مشرف / حقل المطموبة. في هذا البحث ، تم استخدام ثالثة أنواع من تقدير االحتياطيات المس عمارة النفطي الطريقة الحجمية في صيغة رياضية )الجانب الحسابي( وتقنية مونت كارلو لممحاكاة )الجانب petrelومحاكاة المكمن بواسطة برنامج mbalاالحتمالي( ، معادلة توازن المواد المحددة بواسطة برنامج تم تطبيق نتائج هذه الطرق الثالثة بالطريقة الحجمي في الجانب الحسابي الذي المعتمد الجانب الجيولوجي. mmmstb p90،p50( 3.55، 2.22، 1.24( والجانب االحتمالي يساوي )mmmstb 2.25يساوي ) ،p90 عمى التوالي. تم تحديدooip بواسطة برنامجmbal ( 2..2يساوي mmmstb وأخيرا حساب .) . وكانت النسبة المئوية لمخطأ بين (mmmstb 2..1الموديل الجيولوجي بترال كانت )باستخدام ooipحجم ٪ بينما كانت النسبة المئوية لمخطأ بين المعادلة الحجمية و الموديل 20توازن المواد والمعادلة الحجمية تساوي ٪.11الجيولوجي هي المخزون, محاكاة مونت كارلو بالكممات الدالة: حسا iraqi journal of chemical and petroleum engineering vol.15 no.3 (september 2014) 37-50 issn: 1997-4884 study the feasibility of alumina for the adsorption of metal ions from water jenan a. alnajar * , asawer a. kwaeri ** , ramzi h. sayhood ** and abbas h. slaymon *** * chemical engineering department, university of technology, baghdad, ** petroleum technology department, university of technology, baghdad, *** chemical engineering department, college of engineering, university of baghdad, baghdad abstract the present work describes the adsorption of ba 2+ and mg 2+ ions from aqueous solutions by activated alumina in single and binary system using batch adsorption. the effect of different parameters such as amount of alumina, concentration of metal ions, ph of solution, contact time and agitation speed on the adsorption process was studied. the optimum adsorbent dosage was found to be 0.5 g and 1.5 g for removal of ba 2+ and mg 2+ , respectively. the optimum ph, contact time and agitation speed, were found to be ph 6, 2h and 300 rpm, respectively, for removal of both metal ions. the equilibrium data were analyzed by langmuir and freundlich isotherm models and the data fitted well to both isotherm modes as indicated by higher correlation of determination r 2 > 0.87 in both single and binary systems. pore diffusion model for batch adsorption was used to predict the concentration decay curve for adsorption of ba 2+ and mg 2+ onto activated alumina. there was a good agreement between the experimental data and the predicted decay curves using pore diffusion model. keywords: adsorption, magnesium, barium, diffusion model introduction the presence of heavy metals in the environment is of major concern because of their toxicity, bioaccumulating tendency and threat to human life and the environment [1, 2]. these metal ions are presented in wastewater from industrial activities such as mining, metal processing, pharmaceuticals, pesticides, organic chemicals, rubber and plastics, etc [3, 4]. the removal of metals in wastewater has been an important issue for many years due to environmental harm [5]. many methods are used for the removal of heavy metal ions from wastewater including: precipitation, electrolytic process, ultra-filtration, reverse osmoses, ion exchange, solvent extraction, adsorption and biological system [6, 7, 8]. adsorption is an important, highly effective, cheap and easy method among the physicochemical treatment process [9, 10]. a number of materials have been used to remove heavy metals from wastewater such as activated carbon, charcoal, lignite, titanium dioxide, calcium carbon, alumina and clay [11]. alumina can be used as an alternative for activated iraqi journal of chemical and petroleum engineering university of baghdad college of engineering study the feasibility of alumina for the adsorption of metal ions from water 38 ijcpe vol.15 no.3 (september 2014) -available online at: www.iasj.net carbon [12]. alumina is a fine weight material similar in appearance to common salt and it is highly porous and exhibits tremendous surface area, resulting in superior adsorbent capabilities. it is more preferable than activated carbon especially for removing inorganic compounds [13, 14]. barium and magnesium can end up in water and soil due to a number of activities. these activities include the discharge and disposal of drilling wastes, copper smelting, motor vehicle parts, plastic and accessories manufacturing. the presence of these metals in drinking water may cause stomach irritation, muscle weakness, increased blood pressure, or cardiovascular disease. they can be removed by several ways like: reverse somosis, filtration, adding softeners and coagulation. the aim of the present work is to examine environment friendly material like alumina as an adsorbent for removal of magnesium and barium ions from aqueous solution, the effect of different experimental parameters such as adsorbent dosage, concentration of the adsorbate, contact time and ph of the solution under study single and binary systems were investigated, as well as to study the isotherms model and pore model ions to predict the concentration decay curve for the adsorption of ba and mg onto activated alumina. adsorption isotherm adsorption isotherm is defined as the ratio between the amount of material adsorbed per unit weight of adsorbent (qe) and the material concentration in the solution (ce) at equilibrium constant temperature [15]. adsorption isotherm models are used to describe the adsorption isotherm data. several models have been published in the literature to describe experimental data of adsorption isotherm. the langmuir and frundlich models are the most frequently employed models. langmuir isotherm langmuir isotherm was derived in 1916 by irving langmuir [16, 17]. it is one of the most known models which are frequently employed for the determination of adsorption parameter [18]. the langmuir equation is represented by: e e e bc abc q   1 …(1) and the equation may be linearized as: ab c aq c e e e 11  …(2) freundlich isotherm the freundlich isotherm is the earliest known relation presented by herbert freundlich in 1906 [19]. the freundlich equation is represented by: n efe ckq /1  ...(3) the linear form of the equation obtained by taking the logarithm as follows efe c n kq log 1 loglog  …(4) materials and experimental work 1. materials 1.1. adsorbent the adsorbent used was aluminum oxide 90 standardized for column chromatography adsorption analysis, supplied by merck chemical company; the properties of the alumina are listed in table 1: jenan a. alnajar, asawer a. kwaeri, ramzi h. sayhood and abbas h. slaymon -available online at: www.iasj.net ijcpe vol.15 no.3 (september 2014) 39 table 1: properties of alumina product name ,aluminum oxide 90 standardized formula al2o3 particle size range 60-200 µm (70% in this range) specific surface area approx. 120-160 m 2 /g specific pore volume approx. 0.7-0.3 ml/g mean pore size 6 – 15 nm ph (10% aq. suspension) 8.5 – 10.5 bulk density approx. 83.6 g/100 ml ref. merck chemical company 1.2. adsorbate metal ions used in the present work were barium nitrate ba(no3)2 and magnesium nitrate mg(no3)2. 1000 mg/l standard stock solutions of ba 2+ and mg 2+ were prepared by dissolving 1.902 g and 10.540 g, respectively, in one liter of distilled water. 2. experimental work experiments of single and binary system were carried out in batch model. in general, the adsorption experiments were achieved by agitation of 20 ml of metal ion solution (single or binary system solution) of a given mass of adsorbent. the agitation speed was 300 rpm for 30 min. the contact time was 24 h at 20 ˚c. after that the alumina was separated from the liquid phase by filtration through membrane filter 0.45 μm. the filtrate was analyzed to find the remaining metal ion concentration by atomic absorption spectrometer (aas). the ph of the initial solution was adjusted using diluted solution of either 0.1 m hcl or naoh. the following parameters were studied. 2.1. adsorbent dose the effect of adsorbent weight on the adsorption was studied by agitating 20 ml of 50 mg/l of metal ion (ba 2+ , mg 2+ or mixture of them) with different adsorbent weight (0.1 – 2 g) at equilibrium time. these experiments were conducted for single and binary system. 2.2. ph of the solution the effect of ph was studied by adjusting the ph of metal ion solutions (ba 2+ and mg 2+ ) from 3 to 10 by using dilute 0.1 m of hcl and naoh solutions. the experiments were conducted for the single system. 2.3. the concentration of metal ion and adsorption isotherm the effect of metal ion concentration was studied for both single and binary systems. this was carried out by agitating 20 ml of metal ion concentration (50-200 ppm) with 0.5 g alumina for ba 2+ and 1.5 g alumina for mg 2+ . the amounts of metal ion adsorbed by alumina were calculated experimentally using the following equation: )( eoe cc w v q  …(5) the percentage of adsorption of metal ion was calculated using the following equation: 100*re%           o eo c cc moval …(6) result and discussion 1. single system 1.1. effect of adsorbent dosage the effect of alumina dosage for adsorption of ba 2+ and mg 2+ was examined. alumina dosage was varied from 0.1 g to 2 g. this experiment was carried out using fixed volume of metal ion solution of 20 ml and constant metal ion concentration of 50 mg/l, ph of 6, contact time 24 h, 300 rpm agitation speed and at room study the feasibility of alumina for the adsorption of metal ions from water 40 ijcpe vol.15 no.3 (september 2014) -available online at: www.iasj.net temperature of 25 ˚c. the results are presented in fig. 1 for both metal ions. fig. 1: the effect of alumina dose on the adsorption of ba 2+ and mg 2+ in single system, t=20 ˚c, ph= 6, co= 50 mg/l, v= 20 ml solution fig. 1 indicates that metal ion removal increases with increasing weight of alumina. increasing weight of alumina leads to an increase in the number of active sites available for adsorption [20]. also, this figure shows the difference between the adsorption of alumina for both ba 2+ and mg 2+ used. fig. 1 shows the removal of ba 2+ and mg 2+ attained maximum removal at adsorbent dosage of 1 g and 2 g, respectively, with 100% removal. hence 0.5 g and 1.5 g was chosen as the optimum adsorbent dosage for removal of ba 2+ and mg 2+ , respectively. 1.2. effect of ph the ph of aqueous solution is an important controlling parameter in the adsorption process [21]. the influence of ph on the adsorption ofba 2+ and mg 2+ onto alumina at 30 o c and metal ion concentration of 50 mg/l was studied and it is shown in figs. 2 and 3, respectively. the ph range used was (3-10). these figures show that the percentage removal of ba 2+ and mg 2+ increased with increasing ph of the solution. similar behavior has been reported by [22]. the most effective ph was found to be 6 for both metal ions. fig. 2: the effect of ph on the adsorption of ba 2+ in single system, t= 20 ˚c, co= 50 mg/l, w= 0.5 g alumina, v= 20 ml solution fig. 3: the effect of ph on the adsorption of mg 2+ in single system, t= 20 ˚c, , co= 50 mg/l, w= 0.5 g alumina, v= 20 ml solution at low ph values, there is high concentration of h + in the solution; a competition exists between the positively charged hydrogen ions and metal ions for available adsorption sites. the high percentage removal at high ph values is due to the metal precipitation as hydroxides and therefore the removal takes place by adsorption as well asprecipitation. this can be explained by the fact that as ph of solution increases, the oh ions in the solution increase and form some complexes with metal ions and precipitate as metal hydroxide [23, 24]. the optimum conditions for both metal ions were found to be at ph 6. 1.3. effect of initial metal ion concentration the effect of initial concentration of ba 2+ and mg 2+ on adsorption was studied and is shown in figs. 4 and 5, respectively. jenan a. alnajar, asawer a. kwaeri, ramzi h. sayhood and abbas h. slaymon -available online at: www.iasj.net ijcpe vol.15 no.3 (september 2014) 41 fig. 4: the effect of initial concentration of ba 2+ on the adsorption of ba 2+ in single system, onto alumina t=20 o c, ph= 6, m= 0.5 g alumina, v= 20 ml solution fig. 5: the effect of initial concentration of mg 2+ on the adsorption of mg 2+ in single system, onto alumina t=20 o c, ph= 6, m= 1.5 g alumina, v= 20 ml solution it is clear from these figures that the percentage removal of ba 2+ and mg 2+ decreased as the initial concentration of the metal ions increased from 25200 mg/l; this was due to the saturation of the active adsorption sites of the adsorbent with the initial metal ions concentration. in other words, the lower concentration of metal ion solution was fully adsorbed at the active sites present in the alumina and then as the concentration increased the number of active site decreased and later no free sites were available to adsorb. 1.4. equilibrium isotherm studies equilibrium isotherm studies were performed to obtain equilibrium isotherm curves. the adsorption isotherm curves were obtained by plotting the amount of solute (ba 2+ and mg 2+ ) adsorbed per unit weight adsorbent (qe) against the equilibrium concentration of the solute (ce) in the solution. the values of qe for each metal ion were calculated using equation 5. figs. 6 and 7 show the experimental and theoretical adsorption isotherm curve for ba 2+ and mg 2+ at 20 o c. the theoretical data for both metal ions were obtained by using langmuir and freundlich models. fig. 6: adsorption isotherm for adsorption of ba 2+ onto alumina in single system, t=20 o c, ph= 6, m= 0.5 g alumina, v= 20 ml solution fig. 7: adsorption isotherm for adsorption of m 2+ onto alumina in single system, t=20 o c, ph= 6, m= 1.5 g alumina, v= 20 ml solution figs. 6 and 7 show that the experimental data fitted the langmuir model better than freundlich model with ba 2+ and mg 2+ . the corresponding langmuir and freundlich parameters along with the correlation coefficients are given in table 2. as shown in table 2, the correlation coefficient r 2 for langmuir model for both metal ions is slightly greater than that for freundlich model. this study the feasibility of alumina for the adsorption of metal ions from water 42 ijcpe vol.15 no.3 (september 2014) -available online at: www.iasj.net indicates that the experimental data gives best fitting with the langmuir model than the freundlich model for both metal ions. the values of langmuir parameter (a) are the monolayer adsorption capacity and (b) are constant related to the free energy of adsorption and that of freundlich parameter (kf) are constant indicative ofthe relative adsorption capacity of the adsorbent and (b) and(1/n) are constant indicative of the intensity of adsorption. as given in table 2, these parameters vary in the following order: ba 2+ > mg 2+ for a and kf ba 2+ > mg 2+ for b and 1/n the values of the models parameters indicate that the capacity of alumina for these metals followed the order ba 2+ > mg 2+ . table 2: model isotherm parameters for single metal ion adsorption system metal ion langmuir model freundlich model a b r 2 kf 1/n r 2 ba 2+ 3.665 0.210 0.998 0.889 0.331 0.877 mg 2+ 1.098 0.069 0.981 0.244 0.292 0.946 2. binary system 2.1. effect of adsorbent dose the effect of alumina dose on the adsorption of both mg 2+ and ba 2+ in binary system is shown in fig. 8. fig. 8: the effects of alumina dose on the adsorption of both mg 2+ and ba 2+ in binary system. initial concentration of both ions co= 50mg/l, ph=6, v= 20ml solution a similar behavior was obtained for the effect of alumina dose on the percentage removal for the single and binary system; i.e. the percentage removal of both metal ion increases gradually with the amount of absorbent up to a certain value. also, the percentage removal of ba 2+ is greater than that for mg 2+ at the same amount of alumina. this indicates that alumina is more efficient for adsorption of ba 2+ than mg 2+ . fig. 9: the effect of alumina dose on the adsorption of ba 2+ in single and binary system. initial concentration of ba 2+ and mg 2+ in single and binary system i co= 50 mg/l, ph= 6, v= 20 ml solution fig. 10: the effect of alumina dose on the adsorption of both mg 3+ in single and binary system. initial concentration of both ions co= 50 mg/l, ph= 6, v= 20 ml solution jenan a. alnajar, asawer a. kwaeri, ramzi h. sayhood and abbas h. slaymon -available online at: www.iasj.net ijcpe vol.15 no.3 (september 2014) 43 a comparison between the percentage removal for both ba 2+ and mg 2+ in single and binary system is shown in figs. 9 and 10. it can be observed from these figures that the percentage removal in single phase is higher than that in multi-phase; this behavior may be attributed to the competition between these two components to sorption; hence, the chance for getting for both of them will be lowered in multi component system. 2.2. effect of initial metal ion concentration the effect of initial concentration of ba 2+ and mg 2+ in binary system was studied and the results are shown in figs. 11a, 11b, 12a and 12b. (a) (b) fig. 11: the effect of initial ion concentration of (a) ba 2+ and (b) mg 2+ and dose of alumina on the percentage removal of ba 2+ and mg(ii) in binary system these figures show that the percentage removal of ba 2+ and mg 2+ decreases with increasing the initial concentration and increases with the increasing of mass of adsorbent. this is similar to the results obtained by single component system. these figures also show that the percentage removal of ba 2+ is greater than that for mg 2+ . this is because in the case of binary system when the ba 2+ and mg 2+ ions exist in the same solution, competition occurs between them for the active adsorption sites on the adsorbent surface and one of them will occupy the larger number of active sites. in this work, ba 2+ will occupy the greater amount of active sites than mg 2+ and therefore the percentages removal of ba 2+ are greater than mg 2+. as explained in the single system, the alumina is more efficient for the removal of ba 2+ than mg 2+ . figs. 13 and 14 illustrate the comparison between the adsorption rate of metal ions in single and binary system. (a) (b) fig. 12: the effect of initial ion concentration of ba 2+ and mg 2+ on the percentage removal of ba(ii) and mg(ii) in binary system using (a) 0.5 g alumina and (b) 1.5 g alumina study the feasibility of alumina for the adsorption of metal ions from water 44 ijcpe vol.15 no.3 (september 2014) -available online at: www.iasj.net fig. 13: the effect of initial ion concentration of ba 2+ on the percentage removal of ba 2+ in single and binary system fig. 14: the effect of initial ion concentration of mg 2+ on the percentage removal of mg 2+ in single and binary system it can be seen from these figures that the adsorption rate in single component system is greater than that in binary system due to the competition effect in the binary system on the adsorption process as explained above. 2.3. equilibrium isotherm studies the langmuir and freundlich isotherm models were used to describe the adsorption equilibrium data for ba 2+ and mg 2+ onto alumina for binary system as shown in figs. 15 and 16 for ba 2+ and mg 2+ , respectively. it is clear from these figures that the experimental isotherm data for ba 2+ gives good fitting with both langmuir and freundlich isotherm models and the experimental isotherm data for mg 2+ gives better fitting with langmuir model than that with the freundlich model. (a) (b) fig. 15: the adsorption isotherm of ba 2+ in binary system of ba 2 using (a) 0.5g alumina, (b) 1.5g alumina (a) (b) fig. 16: the adsorption isotherm of mg 2+ in binary system of mg 2+ using (a) 0.5g alumina, (b) 1.5g alumina jenan a. alnajar, asawer a. kwaeri, ramzi h. sayhood and abbas h. slaymon -available online at: www.iasj.net ijcpe vol.15 no.3 (september 2014) 45 table 3 shows the adsorption isotherm parameters. it can be seen from table 2 that the value of adsorption capacity a and kf for langmuir model and freundlich model respectively and the correlation coefficient r 2 varies in the following order: ba 2+ > mg 2+ for a, kf and r 2 table 3: model isotherm parameters for binary metal ion adsorption system mass alumina g metal ion langmuir model freundlich model a b r 2 kf 1/n r 2 0.5 ba 2+ 1.840 0.027 0.995 0.155 0.475 0.992 mg 2+ 0.553 0.039 0.997 0.054 0.446 0.873 1.5 ba 2+ 2.932 0.196 0.997 0.485 0.656 0.989 mg 2+ 0.516 0.516 0.999 0.281 0.141 0.907 figs. 17 and 18 show the adsorption isotherm for ba 2+ and mg 2+ in single and binary system. it can be seen from these figures that the adsorption capacity of alumina for adsorption of both metals in single system is greater than that in binary system. this is due to the competition among the metals for activation sites in case of binary system which lowered the adsorption capacity for both metals. it can be noticed from the values of a and kf which take the following order: single>binary for a and kf fig. 17: the adsorption isotherm of ba 2+ in single and binary system, m= 0.5 g alumina fig. 18: the adsorption isotherm of mg 2+ in single and binary system mathematical model for batch adsorption pore diffusion model was used in the present work to describe the adsorption of metal ion in batch system through predicting the concentration decay curve. the mathematical model using pore diffusion model [25] is:  external mass transfer can be obtained by mass balance in the bulk fluid outside the particle: ),( 3 rprpcbc prp fwk dt bdc v   …(7)  interpartical diffusion can be obtained from the mass balance of metal ion inside the porous adsorbent particle:                    r pc r rr pdp t pc p dt q p 2 2 2 1  …(8) the initial and boundary conditions are: i.c.: ob cc  , 0 p c , 0q , 0t …(9) bc: 0 0    r p t c , 0 0    r r q 0r , …(10) ),( rprpcbcfkrr r pc pdp p      prr  …(11) study the feasibility of alumina for the adsorption of metal ions from water 46 ijcpe vol.15 no.3 (september 2014) -available online at: www.iasj.net where b c and p c are the solute concentration in the bulk liquid and particle phase, respectively. local equilibrium was assumed between the solute in the pore and the solute adsorbed in the pore surface. this local equilibrium was represented by the langmuir: p pe bc bcq q   1 …(12) the external mass transfer coefficient can be correlated in term of dimensionless correlation. the following correlation was developed based on the experimental data [26]: 461. 019,0 / 011.0173.0283.0 re046.0 o sc pd t ugamsh           …(13) equation (11) is valid for: 104 < rem < 3×104; 1.1×105 < ga < 106; 300 <sc<2000 and 27 < u < 2900, where u is a group characterizing the solid concentration. this correlation has a deviation between experimental and calculated value of 2.5%. the external mass transfer coefficient can be obtained by the analytical solution for equation 6 and where at t = 0, cp,r=rp = 0 and cb = co , hence:          oc tc wt vppr fk ln 3  ...(14) the set of partial differential equations 7-12 were first solved by reduction to a set of ordinary differential equation, ode, using the finite element, fe, and orthogonal collocation, oc, methods, respectively. the resulting ode system was solved using an existing ode solver provided by matlab v7. the mathematical model was developed to obtain the theoretical concentration decay curve. the experimental concentration decay curves for each metal ion (ba +2 and mg +2 ) were obtained by plotting ce/co versus time, at different agitation speeds. figs. 19 and 20 show the experimental concentration decay curve at different agitation rates and that is predicted by the mathematical model for ba 2+ and mg 2+ , respectively, at different agitation rates. the mathematical model used was the pore diffusion model. these figures show a good fitting between the experimental and predicted results. the results for adsorption for both metals slightly change with agitation speed. fig. 19: the experimental concentration decay curve and that predicted by pore diffusion model for adsorption ba 2+ in single component system at different agitation speed fig. 20: the experimental concentration decay curve and that predicted by pore diffusion model for adsorption mg 2+ in single component system at different agitation speed jenan a. alnajar, asawer a. kwaeri, ramzi h. sayhood and abbas h. slaymon -available online at: www.iasj.net ijcpe vol.15 no.3 (september 2014) 47 1. the external mass transfer coefficient kf and the pore diffusion coefficient dp the principal parameters required for using the program were the external mass transfer coefficient kf and the pore diffusion coefficient dp. by minimizing the differences between the theoretical and experimental decay curves for the batch adsorption, it was possible to obtain the individual dp and kf for each metal ion using the langmuir isotherm equation [27] as presented in the table 4. there was a good agreement between the batch experimental data and the predicted decay curves using pore diffusion model for batch operation and the pore diffusion coefficient for each metal ion were found to be: table 4: model isothermal parameters for binary material ions adsorption system metal ion dp, m2/s kf .m/s ba 2+ 8.0x10 -9 3.600x10 -5 mg 2+ 4.5x10 -9 0.573x10 -6 conclusions 1the metal ion removal of ba 2+ and mg 2+ increased with increasing the alumina dosage for single and binary system. the optimum dosage of alumina was found to be 0.5 g and 1.5 g for removal of ba 2+ and mg 2+ , respectively. 2the percentage removal of ba 2+ and mg 2+ decreased as the initial concentration of metal ion increased for single and binary system. 3in single system, the percentage removal of ba 2+ and mg 2+ increased with increasing the alkalinity of the solution. the optimum ph was found to be ph 6. 4the experimental adsorption data fitted well with both langmuir and freundlich isotherm model in single system. 5in binary system, the percentage removal of ba 2+ was greater than that of mg 2+ at the same weight of alumina and initial concentration of metal ion. 6the percentage removal of metal ion in singular system is greater than that in binary system. 7in binary system, the experimental data of ba 2+ was fitted by both langmuir and freundlich isothermal model while mg 2+ results showed better fitting with langmuir model. 8the experimental data were modeled using pore diffusion mathematical model with good agreement. nomenclature a external surface area per unit volume of the particle m 2 /m 3 b langmuir constant related to energy of adsorption l/mg c fluid phase concentration mg/l cb the solute concentration in the bulk fluid. mg/l ce equilibrium liquid phase concentration mg/l co initial liquid phase concentration mg/l cp the solute concentration in the particle phase mg/l dp pore diffusion coefficient m 2 /s dm molecular diffusivity m 2 dp particle diameter m g gravitational force (9.8) m/s 2 kf concentration in freundlich relating to adsorption capacity (mg/g) (l/mg) 1/n kf external film mass transfer coefficient m/s study the feasibility of alumina for the adsorption of metal ions from water 48 ijcpe vol.15 no.3 (september 2014) -available online at: www.iasj.net n freundlich constant relating to adsorption intensity qe equilibrium solid phase adsorbate concentration mg/g r radial coordinate m s surface area m 2 r correlation coefficient rp radius of particle m t time s t temperature k v volume of solution m 3 v superficial velocity m/s w mass of adsorbent g creek symbols ɛp porosity of adsorbent particle µc kinematics viscosity m 2 /s µw water viscosity m 2 /s ρ density kg/m 3 ρw density of water kg/m 3 dimensionless group sh sherwood number m pf d dk re reynolds number w pw d   rem reynolds number 3 4 c p pd  sc schmidt number mw w d  ga galileo number 2 3 c p gd  u solid concentration group p sd w  references 1geetha v.v., ram k.s. and vaishali s., (2013), “a comparative study on the removal of heavy metals by adsorption using fly ash and sludge: a review”, international journal of application or innovation in engineering and management (ijaiem), 2,(7), p.4556. 2addagalla v. a., naif a. d. and nidal h., (2009) “study of various parameters in the biosorption of heavy metals on activated sludge”, world appl. sci. j., 5 (special issue for environment), p.32-40, 3nurul a.b.r., norhafizah b a.h., wong c. s., (2013), “removal of cu(ii) from water by adsorption on chicken egghell”, international journal of engineering and technology (ijet-ijets, 13, p.4045. 4ping g. and fengting l., (2011), “kinetics and thermodynamics of heavy metal cu(ii) adsorption on mesoporous silicates”, polish j. of environ. stud, 20, p.339-344. 5zouboulis, a.i , loukidou, m.x and matis, k.a, (2004),“biosorption of toxic metals from aqueous solutions by bacteria strains isolated from metal-polluted soils”, process biochemistry 39, (8), p.909–916. 6blais, j. f., djedidi, z., ben cheikh, r., tyagi, r.d.; and mercier, g., (2008), “metals precipitation from effluents: review”, asce, 12, (3), p.135-149. 7barakat, m.a., (2011),“new trends in removing heavy metals from industrial wastewater”, arabian journal of chemistry, 4, (4), p.361–377. 8subramani, t. and sindhu, s., (2012), “batch study experiments and column analysis for finding out a suitable biosorbentfor the removal of heavy metals from electroplating industry effluent”, international journal of engineering research and applications, 2,(4), p.172-184. 9mohammad a.,rifaqat a. k. r., rais a., and jameel a., (2000), http://www.sciencedirect.com/science/article/pii/s0032959203002000 http://www.sciencedirect.com/science/article/pii/s0032959203002000 http://www.sciencedirect.com/science/article/pii/s0032959203002000 http://www.sciencedirect.com/science/journal/13595113 http://www.sciencedirect.com/science/journal/13595113 http://www.sciencedirect.com/science/journal/13595113/39/8 http://0-www.sciencedirect.com.precise.petronas.com.my/science/article/pii/s1878535210001334 http://0-www.sciencedirect.com.precise.petronas.com.my/science/journal/18785352 http://0-www.sciencedirect.com.precise.petronas.com.my/science/journal/18785352 http://0-www.sciencedirect.com.precise.petronas.com.my/science/journal/18785352/4/4 http://www.sciencedirect.com/science/article/pii/s030438940000234x http://www.sciencedirect.com/science/article/pii/s030438940000234x http://www.sciencedirect.com/science/article/pii/s030438940000234x http://www.sciencedirect.com/science/article/pii/s030438940000234x jenan a. alnajar, asawer a. kwaeri, ramzi h. sayhood and abbas h. slaymon -available online at: www.iasj.net ijcpe vol.15 no.3 (september 2014) 49 “adsorption studies on citrus reticulata (fruit peel of orange): removal and recovery of ni(ii) from electroplating wastewater”, journal of hazardous materials, 79,(1–2), p.117–131. 10krajewska, b., (2004), “application of chitinand chitosan-based materials for enzyme immobilizations: a review”, enzyme and microbial technology35, ( 2–3), p.126–139. 11zahra s., reyhane s. and reza f., (2013), “fixed-bed adsorption dynamics of pb (ii) adsorption from aqueous solution using nanostructured γ-alumina”, journal of nanostructure in chemistry, 3:48, p.1 of 8 12roberto l.-r., nahum a. m.-c., araceli j.-a., jovita m.-b., lilia e. l.-r., jose m. m.-r. and antonio a.-p., (2008), “fluride removal from water solution by adsorption on activated alumina prepared from pseudo-boehmite”, j. environ. eng. manage., 18(5), p.301-309. 13molinari, roberta c., nevio p. and pietro a.,“(2004), “removal from wastewaters by a new synthesized selective xtractant and slm viability”, ind. eng. chem. res., 43 (2), p.623–628. 14debabrata m., debabratag.andpratip b.,(2011),“treatment of electroplating wastewater by adsorption technique”, international journal of civil and environmental engineering 3:2. 15itodo, h.u. and itodo a.u., (2010),“surface coverage and adsorption study of dye uptake by derived acid and base treated mango seed shells, j. chem. pharm. res., 2(3), p. 673-683. 16charles h.g., david s. and alan h., (1974), “a general treatment and classification of the solute adsorption isotherm i. theoretical”, journal of colloid and interface science, vol. 47(3), p.755-765. 17ho, y.s., porter, j.f. and mckay, g., (2002), "equilibrium isotherm studies for the sorption of divalent metal ions onto peat: copper, nickel and lead single component systems", water, air and soil pollution, 141, p. 1-33. 18seungman s.and dongsu k., (2005),“modification of langmuir isotherm in solution systems— definition and utilization of concentration dependent facto”r, chemosphere, 58 , p.115–123. 19robert j.u., sarah c.b.,miguel b., john k.b.jr., ripaln.s.h, kcn d.s., (2001), “application of the freundlich adsorption isotherm in the characterization of molecularly imprinted polymers”, analyticachimicaacta 435 , p.35– 42. 20santanu p. and kartic c.k., (2004),“a review on experimental studies of surfactant adsorption at the hydrophilic solid–water interface, advance in collide and interface science”, 110, (2), p.7595. 21a. akber hussain, s. raja mohammed, m. nallu and s. arivol, (2012),“adsorption of fe(iii) from aqueous solution by acanthaceaeactivated carbon, journal of chemical and pharmaceutical research”, 4(4), p.2325-2336. 22mehmet e.a., sukru d., celalettin o. and mustafa k., 2007, “heavy metal adsorption by modified oak sawdust:thermodynamics and kinetics”, journal of hazardous materials 141,p.77–85. 23paul chen, j. and lin, minsheng, (2001), “surface charge and metal ion adsorption on an h-type activated carbon: experimental http://www.sciencedirect.com/science/journal/03043894 http://www.sciencedirect.com/science/journal/03043894 http://www.sciencedirect.com/science/journal/03043894/79/1 http://www.sciencedirect.com/science/article/pii/s0141022904001231 http://www.sciencedirect.com/science/journal/01410229 http://www.sciencedirect.com/science/journal/01410229 http://www.sciencedirect.com/science/journal/01410229/35/2 http://pubs.acs.org/action/dosearch?action=search&author=molinari%2c+raffaele&qssearcharea=author http://pubs.acs.org/action/dosearch?action=search&author=cassano%2c+roberta&qssearcharea=author http://pubs.acs.org/action/dosearch?action=search&author=picci%2c+nevio&qssearcharea=author http://pubs.acs.org/action/dosearch?action=search&author=argurio%2c+pietro&qssearcharea=author study the feasibility of alumina for the adsorption of metal ions from water 50 ijcpe vol.15 no.3 (september 2014) -available online at: www.iasj.net observation and modeling simulation by the surface complex formation approach”, carbon,39 ,p.1491–1504. 24hamdi a. m. bennour, 2012, “influence of ph and ionic strength on the adsorption of copper and zinc in bentonite clay “, chem. sci. trans., 1(2), p.371-381. 25leyva-ramos, r and geankoplis, c.j., 1985, "model simulation and analysis of surface diffusion of liquids in porous solids", chem. eng. sci., 40(5), pp. 799-807. 26boon-long, s., laguerie, c. and couderc, j.p., 1978, "mass transfer from suspended solids to a liquid in afitated vessels", chem. eng. sci., 33, pp.813-819. 27abbas h,s.,andkawther w.a., (2008),competitive adsorption of furfural and phenolic compounds onto activated carbon in fixed bed column, environmental science and technology, jan 15 http://www.nextbio.com/b/search/author/kawther%20w%20ahmed ijcpe vol.9 no. 2 (june 2008) iraqi journal of chemical and petroleum engineering vol.9 no.2 (june 2008) 17-23 issn: 1997-4884 kinetic study on catalytic wet air oxidation of phenol in a trickle bed reactor wadood t. mohammed * , sama m. abdullah ** *’ ** chemical engineering department college of engineering university of baghdad – iraq abstract kinetics study on the phenol oxidation by catalytic wet air oxidation (cwao) using cuo.nio/al2o3 as heterogeneous catalyst is presented. 4 g/l phenol solution of ph 7.3 was oxidized in a trickle bed reactor with gas flow rate of 80% stochiometric excess (s.e).. in order to verify the proposed kinetics, a series of cwao experimental tests were done at two temperatures (140 and 160° c), oxygen partial pressures (9 and 12 bar), and weight hourly space velocity (whsv) (1, 1.5, 2, 2.5, and 3 h -1 ). according to power law, the reaction orders are found to be approximately 1 and 0.5 with respect to phenol concentration and oxygen solubility, respectively. these values favorably compare with those cited in the literature for intrinsic kinetics, which indicates minimal mass transfer limitations in the trickle bed reacting system used in this study. introduction the petrochemical, chemical and pharmaceutical industries produce waste waters containing organics, such as phenols, which are extremely toxic to aquatic life [1]. the phenol and derivatives are generally toxic even at very low concentrations [2]. in general, these pollutions exist in concentration range of 500-10000 ppm, mostly too toxic for conventional biotreatment methods, and too low to treat by combustion [3]. thus, chemical oxidation emerges as a promising route for phenol removal at intermediate concentrations [4]. wet air oxidation (wao) is considered an emergent technology that economically can depollute organic wastewaters in order to meet the progressively more stringent environmental regulations [5]. normally a typical wao process requires elevated pressure (0.5-20 mpa) and temperature (125-320 °c) in order to enhance the solubility of oxygen in aqueous solution. in reality such requirements will inevitably lead to higher equipment and operational costs (6). thus, cwo appears as an economically and ecologically promising technique to convert refractory organic compounds, such as phenol, into carbon dioxide or harmless intermediates at mild pressure and temperature conditions (7). this work deals with kinetics study of the catalytic phenol oxidation in aqueous phase using fixed bed reactor working in trickle flow regime. air was used as oxidizing agent. copper based catalyst supported on γalumina was employed. the detailed examination of the product dependence on the space time is provided in the temperatures 140 and 160 °c, and between 9 and 12 bar of oxygen partial pressure. theory the ideal plug flow pseudo-homogeneous model presented in the equation 1 that proposed by froment and bkchoff (1990) was modified to describe the reactor in terms of space time, instead of reactor length. university of baghdad college of engineering iraqi journal of chemical and petroleum engineering kinetics study on catalytic wet air oxidation of phenol in a trickle bed reactor 20 ijcpe vol.9 no. 2 (june 2008)   0. .  phb phl r dz cud  (1) ph ph r d d c    (2) the first step is to consider only the phenol degradation reaction described by equation 3 c6h6o + 7o2 → 6co2 + 3h2o (3) in agreement with observations in the literature (8, 9, 5, 10, 2, 11, 12), a simple power law was convenient to accurately describe the phenol oxidation. thus, the following rate equation for phenol destruction was used:  phobph ckr . (4)   2 .. o ob ob p rt kk         (5) phph rr  (6)   phob ph ck d dc . (7) equation 4 can be line raised in the following way:     phobph logcklogrlog  (8) in the present study, the above expression for ob k was modified to incorporate the oxygen mole fraction in the liquid phase, 2o x instead of the partial pressure, leading to:   2 .. o ob ob x rt e kk        (9) i.e.   pho ob ph cx rt e kr ... 2        (10) this was done because the reaction actually takes place in the liquid phase. thus, the solubility of oxygen characterizes the oxygen contribution to the kinetic expression rather than the oxygen partial pressure. furthermore, the oxygen solubility is not only a function of pressure but also of temperature. therefore, the oxygen mole fraction in the liquid phase was considered to be more representive. this mole fraction was calculated using henry law (13) , henry law is given by equation 11. 222 . ooo xhp  (11) experimental work material and catalyst preparation the phenol used as reagent was purchased from griffin. high purity synthetic air was used as oxidant. deionized water was used to prepare catalyst and different aqueous solutions. glass balls were used in the tests with inert material. γ-alumina was used as support for the copper. copper nitrate from fluka was used as active component. nickel nitrate from bdh chemicals ltd. was used as promoter. copper-based catalyst was prepared using γalumina as support. the alumina, which was supplied as spheres of 2.5 mm diameter, was dried for 4 h at 110°c. the catalyst was made with a copper oxide loading of 10% and 2% nickel oxide prepared by the pore volume impregnation method using aqueous solutions of copper nitrate (26 g copper nitrate and 6.3 g nickel nitrate dissolved in 45 ml hot deionized water) for impregnating the support. later, the catalyst was dried at 110°c overnight, followed by calcining at 400°c for 8 h with air. table 1 lists the main physical characteristics of the catalyst prepared and support used which were done in the state company of geological survey and mining. fig. 1: experimental setup wadood t. mohammed and sama m. abdullah 21 ijcpe vol.9 no. 2 (june 2008) table 1 the main physical characteristics of different catalysts prepared and supports used. experimental set-up and procedure the continuous oxidation of phenol was carried out in a packed bed reactor. the fixed bed reactor consists of a ss-316 tubular reactor, 80 cm long and 1.9 cm inner diameter and controlled automatically by for sections of 15 cm height steel-jacket heaters. independent inlet systems for gas and liquid feed allow working at various liquid to gas flow rate ratios. the liquid feed is stored in a feed tank, which is connected to a high-pressure metering pump (dosing pump) that can dispense flow rates between 0 and 15 ml/min at constant pressure. the air oxidant comes from a high pressure cylinder equipped with a pressure controller to maintain the operating pressure constant. a flow-meter coupled with a high precision valve is used to measure and control the gas flow rate. the liquid and gas streams are mixed and then entered to the reactor at the required temperature. the mixture flows along the bed packed with 85 cm3 (30 cm height) of the catalyst enclosed between two layers of inert material (also a flexible grid put at the top and bottom of the reactor to prevent movement of particles).the exited solution goes to a liquid-gas separation and sampling system, regularly, liquid samples were withdrawn for analysis. figure 1 illustrated the experimental setup. to verify that only the catalyst causes the oxidation of the phenol, test was made using an inert material (γ-alumina). the phenol removal was negligible, less than 0.1 %, which falls within the experimental error. ph-adjustments the ph of 4 g/l phenol solution is slightly acid, about 5.9. however, for phenol solution of ph 7.3, the feed solution was adjusted by adding sodium hydroxide solution. to measure ph of the solution oakion ph2100 series was used. the procedure was summarized as following: ph meter was calibrated previous to use by using buffer solutions. measuring the ph of 4 g/l phenol solution. adding particular quantities of naoh solution to the 4 g/l phenol solution according to the titration method to obtain solution of ph 7.3. products analysis to analysis phenol concentration in the outlet samples, shimadzu model uv-160a ultraviolet/visible spectrophotometer was used. estimation of reaction orders according to the differential method, the derivatives d dc ph are evaluated from the experimental data to obtain the reaction rate ( ph r ) as shown in the figure 2. then,   ph rlog  is plotted against   ph clog in equation 8 as shown in the figure 3, to determine values of and ob k . it should be noted that all above calculations were done using computer. to calculate the other unknown kinetic parameters  k , ob e and  , equation 9 can be line raised in the following way: rt e xkk ob oob  2 lnlnln  (12) alternative steps were done using different values of ob k available at different temperatures and pressures to evaluate these parameters. catalyst γ-al2o3 cat. active phase (cuo), % 10 promoter (nio), % 2 support γ-al2o3 calcinations temperature, o c 400 pore volume, cm 3 /g 0.44 0.352 bulk density, g/cm 3 0.68 0.748 surface area, m 2 /g 289 237 kinetics study on catalytic wet air oxidation of phenol in a trickle bed reactor 22 ijcpe vol.9 no. 2 (june 2008) -10 0 10 20 30 40 50 -0.2 0 0.2 0.4 0.6 0.8 1 1.2 space time, h c p h ,m m o l/ l results and discussion a first reaction order for phenol concentration given by equation 10 was found, in agreement with findings of the other studies conducted in slurry reactor (14, 15) or trickle bed reactor (tbr) (10, 16, 11, 12). a 0.5 oxygen order was found on reaction rate as found by (14, 15, 10, 11, 12). this results explained that as disscociative oxygen adsorption is an elementary step during cwao of phenol over copper oxide catalyst and reported 0.5 oxygen order (15), while reported 0.5 (  0.1)(9). the observed activation energy for phenol destruction over cuo.nio.al2o3 was found to be 78.5 kj/mol. falls in the range of the 85(  2) kj/mol (9) and 77.1(  4) kj/mol (10) in the same tbr using the cu0803 catalyst, while for stirred slurry reactors intrinsic kinetic values of 85 kj/mol (17) and 84 kj/mol (15) for different copper oxide catalysts with similar characteristics. considerably, the oxidation reactions of phenol to 4-hba (equation 13) and p-benzoquinone (equation 14) have activation energies of 82.4 and 72 kj/mol were obtained in the tbr over active carbon as catalyst (12) c6h6o + co2 → c7h6o3 13 c6h6o + o2 → c6h4o2 + h2o 14 it is well known that the big gas/liquid ratio employed by this type of reactor permits better contact between the gas and liquid phases thus improving the mass transfer between phases and suggesting that the mass transfer limitation can indeed be neglected. the frequency factor was found 3.2×1011.36 l / kg cat. h close to the values 1011 l/kg cat. h (9), 1011.36 l/kg cat. h (10) and 1014.35 and 1013.66 respectively (12). when those results are compared with the once in this study, it can be seen that the kinetic parameters are slightly different or closed to the values given in the literature. the difference in the results may arise from the reaction conditions and the type of catalyst used. finally the reaction rate equation is: 5.011 2 . 5.78538 .102.3 ophph xc rt r        15 fig.2: concentration of phenol versus space time at various conditions. reaction conditions: type of catalyst= cat.4, feed solution ph=7.3, s.e. = 80%, and initial phenol concentration= 4 g/l. fig. 3: log (-rph) versus log cph at various conditions 140° c and 9 bar 160°c and 9 bar 160° c and 12 bar best fit 0 0.5 1 1.5 2 2.5 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 log cph l o g (r p h ) 140° c and 9 bar 160°c and 9 bar 160° c and 12 bar best fit wadood t. mohammed and sama m. abdullah 23 ijcpe vol.9 no. 2 (june 2008) conclusions the experimental results of cwao of phenol showed that the oxidation reaction of phenol is first order with respect to phenol concentration and o.5 order with respect to oxygen solubility, observed activation energy equal to 78.5 kj/mol and pre-exponential factor equal to 3.2 ×1011 l/kg cat. h. nomenclature cph : concentration of phenol mmol /l ea : activation energy j / mol h : henry constant ko : frequency factor (case dependent units) kob : observed rate constant (case dependent units) 2o p : oxygen partial pressure bar r : universal gas constant, 8.314 j / mol. k rph : phenol reaction rate mol / kg. s t : temperature k 2 o x : mole-fraction of oxygen z : reactor length (case dependent units) reference 1. harmankaya, m. and gündüz, g., journal of engineering and environmental sciences, 22, 9-15 (1998). 2. massa, p.a., ayude, m.a., fenoglio, r.j., gonzalez, j.f. and haure, p.m., latin american applied research, 34, 133-140 (2004). 3. aljailawi, w., guo, j. and al-dahhan, m., environmental engineering reu program, 1-16 (2003). 4. miro, c., alejamdre, a., fortuny, a., bengoa, c. font, j. and fabregat, a., water research, 33, 10051013 (1999). 5. eftaxias, a., font, j., fortuny, a., giralt, j., fabregat, a. and stuber, f., applied catalysisb: environmental, 33, 175-190 (2001). 6. wu, q., hu, x., yue, p.l., chemical engineering science, 58, 923-928 (2003). 7. fortuny, a., miro, c., font, j. and fabregat, a., catalysis today, 48, 323-328 (1999). 8. fortuny, a., ferrer, c., bengoa, c., font, j. and fabregat, a., catalysis today, 24, 79-83 (1995). 9. fortuny, a., bengoa, c., font, j., gastells, f. and fabregat, a., catalysis today, 53, 107-114 (1999). 10. eftaxias, a., catalytic wet air oxidation of phenol in a trickle bed reactor: kinetics and reactor modeling, ph. d. thesis, rovira i virgili university, targgona, (2002). 11. eftaxias, a., font, j., fortuny, a., fabregat, a. and stuber, f., journal of chemical technology and biotechnology, 80, 262 (2005). 12. eftaxias, a., font, j., fortuny, a., fabregat, a. and stuber, f., applied catalysisb: environmental, xxx, xxx-xxx (2006). 13. himmelblau, d. m., journal of chemical and engineering data, 184, 39 (1960). 14. sadana, a. and katzer, j. r., industrial and engineering chemistry fundamental, 13, 127-134 (1974). 15. pintar, a. and levec, j., journal of catalysis, 135, 345 (1992). 16. suwanprasop, s., oxydation catalytique en voie humide du phenol sur charbon actif, ph. d. thesis, chulalong korn university, thailande, (2005). 17. ohta, h, goto, s. and teshima, h., industrial and engineering chemistry fundamental, 19, 180-185 (1980). α oxygen order β organic order ρb bed density kg / m 3 τ space time h ijcpe vol.9 no.4 (2008) iraqi journal of chemical and petroleum engineering vol.9 no.4 (december 2007) 13-20 issn: 1997-4884 adsorption of btx aromatic from reformate by 13x molecular sieve abdul halim a.k. mohammed* and maisa mehdi abdul-raheem *chemical engineering department college of engineering university of baghdad – iraq abstract this work deals with separation of the aromatic hydrocarbons benzene, toluene, and xylene (btx) from reformate. the separation was examined using adsorption by molecular sieve zeolite 13x in a fixed bed process. the concentration of aromatic hydrocarbons in the influent and effluent streams was measured using gas chromatography. the effect of flow rate and bed length of adsorbent on the adsorption of multicomponent hydrocarbons and adsorption capacity of molecular sieve was studied. the tendency of aromatic hydrocarbons adsorption from reformate is in the order: benzene >toluene>xylenes. introduction barrer and his associates have shown that certain natural and synthetic zeolites may be used as molecular sieve adsorbents for the separation of hydrocarbons and other compounds. a method has been developed for separating certain aromatic hydrocarbons according to shape and size of the molecules. the mixture of aromatic hydrocarbon is introduced in to a column containing the molecular sieve adsorbent. the method was tested with mixture of pure aromatic hydrocarbons and with petroleum fractions contained of mononuclear, dinuclear, and trinuclear aromatic in the c15 to c25 range [1]. richard w.neuzil, and downer grove, proposed crystalline aluminosilicate adsorbent containing barium and potassium cations for the separation of c8 aromatic components from a feed mixture containing at least two c8 aromatic hydrocarbons. a feed mixture is contacted with an adsorbent wherein one component of the feed preferentially adsorbed by the adsorbent. the preferentially adsorbed component of the feed is there after recovered utilizing a desorption step [2]. k.al-zaid, f.owaysi, s.akashah and y.a.eltekov measured the equilibrium extent, kinetic and dynamic of adsorption of individual aromatic hydrocarbon (ndodecylbenzene, naphthalene, and dibenzothiophene) from iso-octane solutions by molecular sieves 13x using a temperature of 343 k and at concentration of aromatic hydrocarbons 30 kg/m 3 . the separation factor and number of adsorbate molecules occupied in the unit cell of the molecular sieve were calculated. the diffusion coefficients were determined using barrer-brook equation. the mass transfer zone has been determined using modified shilov equation and dynamic system of adsorption [3]. according to the work of owaysi et al, aromatic hydrocarbon impurities are removed from a liquid paraffin in the liquid phase at relatively low temperatures with an x-type zeolite molecular sieve material. the contacting is performed without recycle and purified liquid paraffin containing less than about 0.01% by weight aromatic is obtained [4]. d.ahmetov and s.svel-cerovecki have performed a series of experiments in a small laboratory apparatus with fixed bed of the adsorbent to estimate the suitability of molecular sieve 13x for the preparation of low aromatic solvents from gasoline, white spirit and kerosene and also the optimal conditions for university of baghdad college of engineering iraqi journal of chemical and petroleum engineering adsorption of btx aromatic from reformate by 13x molecular sieve 14 ijcpe vol.9 no.4 (2008) performing dearomatization in a large laboratory apparatus[5]. a refinary reformate comprised of 6 wt% benzene and 25 wt% c8 aromatics (xylenes and ethyl benzene) was passed through an adsorption column of a bed of 300 gm nax zeolite absorbent at room temperature [6]. samples of treated feed, as it exited the column, were analyzed in time intervals from 5 to 50 minute and the benzene reaches breakthrough time at 22 minute while the c8 aromatics at 20 min and for c8 aromatics at time 35min. this means that the adsorbent reached the saturation and no more adsorption take place until the adsorbent was regenerated or desorbed. the adsorbent was desorbed by passing toluene through the bed of adsorbed at flow rate of 20 cm3/min and the concentration of benzene of c8 aromatic was monitored at these time intervals . the desorbed of c8 aromatics from adsorbent is finished at time 20 min while for benzene the desorption is finished from adsorbent at time 25 min [6]. the present study is a trial to separate btx from the reformate feed supplied from al-daura refinary by adsorption technique using molecular sieve zeolite 13x. experimental work materials reformate reformate is obtained from catalytic reforming of naphtha. catalytic reforming leaves the number of carbon atoms in the feed stock unchanged but increases the aromatic content. the feedstock (reformate) in this study is received from al-duara refinary. the properties of reformate are given in table 1. table 1 properties of reformate adsorbent the adsorbent column is packed with 13 x molecular sieve obtained from”rhone poulene”. table 2 shows the properties of 13x molecular sieve table 2 properties of 13x molecular sieve typical properties description normal pore diameter (a) 10 bulk density (gm/cm 3 ) 0.64 extrudate diameter (mm) 1.6 loss on ignition (wt %) 1 average crushing strength (kg/m) 3 static adsorption at 10% relative humidity (grams of h2o /100 gm adsorbent) 21.5 static adsorption at 60% relative humidity (grams of h2o /100 gm adsorbent) 25.5 total pore volume (cm 3 /gm) 0.285 apparent porosity (%) 35.85 particle density (gm/cm 3 ) 1.2579 void fraction of the bed 0.4912 api gravity 54.9 specific gravity at 60f/60f 0.759 boiling range (c) 90-180 flash point (ºc) 25 btx content, vol% benzene toluene p and m xylene o-xylene 3.18 14.49 17.66 11.58 astm distillation distillate, vol.% boiling point,(c) ibp 10 20 30 40 50 60 70 80 90 95 fbp 43 71 80 86 92 97 103 110 121 144 154 180 abdul halim a.k. mohammed and maisa mehdi abdul-raheem 15 ijcpe vol.9 no.4 (2008) adsorption procedure the experimental apparatus show in figure 1 consists of 2.5 liter glass container, connected with dosing pump. the flow inducer dosing pump is supplied from watson –marlow-limited. adsorption column has 1.5 cm inside diameter and 100 cm long. it is packed with 13x molecular sieve adsorbent. the bottom of adsorption column is fitted with valve. 50 ml receiver is used for collection of effluent. the collected product is analyses by gas chromatograph for determination the concentration of aromatic hydrocarbons. fig.1: schematic flow diagram of experimental apparatus a known quantity of 13x molecular sieve was activated by heating in electronic furnace (nabertherm) to remove the water of hydration and empty the pores at 275c for 2 hours. the polymer balls are placed in the bottom of column then a known quantity of zeolite 13x is charged in the adsorption column. the zeolite is packed by gentle tapping through it’s length to avoid or reduce the channeling and voidage, which effect the adsorption capacity by loss the actual surface area of 13x zeolite. in the top of adsorption bed polymeric balls pvc is added for good feed distribution. the feed is pumped to adsorption bed at desired flow rate. the feed is moved through the bed until the product begins to collect continuously. the product is received at intervals time for obtaining the concentration of adsorbate at each time to build the breakthrough curve. this means that the saturation of adsorbent is over. the parameters, which is affected on adsorption capacity are flow rate and bed weight. the effect of bed weight in the range 40-70 gm and the flow rate in the range of 0.16-1 cm 3 /min on adsorption capacity was studied. chromatographic analysis the gas chromatography of type shimadzu-gc 14a was used. nitrogen was used as a mobile phase, supplied from the gas cylinder, purity of 99.9%. the chromatographic system used consists of three essential elements. these are injection system, temperature-controlled column, and detector. stainless steel packed column used has outside diameter 1/8 inch and 4 m long. the column was packed with chromosorb paw. the particle size of the support is 60-80 mesh. this support coated with stationary phase of type 1, 2, 3tris (cyanoethoxy)propane (tcep). the loading of tcep is 25%. the isothermal temperature of column tcep, injection temperature, and detector temperature are 100,200, and 210c, respectively. the flow rate of the nitrogen carrier gas is 25cm 3 /min. the flow rate of hydrogen and air, which are used for flame ignition of fid, are 25 and 400 cm 3 /min, respectively. the retention times of benzene, toluene , p and m xylenes, and o-xylene , determined by injection of the standard samples , are 6.526, 10.097, 15.440 and 20.867 minutes, respectively. results and discussion effect of multicomponent system on adsorption for a multicomponent system where coadsorption takes place, the design almost totally depends on experimental and field performance data. in general, the adsorbent bed behaves as a chromatographic column because of difference in affinities of various adsorbents [8]. the multicomponent of aromatic hydrocarbons in reformate are listed in table (1). detailed design of multicomponent adsorption may also have to take into consideration the “rollup” effects due to coadsorption[9]. the tendency of aromatic hydrocarbons adsorption from reformate is in the order :benzene >toluene >xylenes. these components in the beginning of the run may be adsorbed compared with o-xylene; therefore, o xylene displaced from the adsorbent to give higher concentration in the effluent streams than originally presented in the feed. when p and m xylenes begin to adsorb some of the o-xylene is readsorbed. this leads to rollup the concentration of o-xylene in the effluent stream to a level above that of adsorption of btx aromatic from reformate by 13x molecular sieve 16 ijcpe vol.9 no.4 (2008) the feed. as shown in tables (3)-(5) the c/c0 of oxylene are 1.732, 2.532 and 1.759 at flow rates 0.16, 0.35, and 1 cm3/min, respectively. these higher concentrations of o-xylene indicate that the bed is saturated with respect to o-xylene. similarly the more strongly adsorbed toluene displaces some of p and m xylenes from the surface of adsorbent until finally toluene begins to break the bed. these lead to rollup the concentration of p and m xylenes above feed concentration. this behavior of xylenes may be due to the different speed of adsorption for these components, so, xylenes propagate with the faster moving front at the first. benzene, which more strongly adsorbed, compared with the other components will rollup the toluene at some runs to higher concentration, which depends on the equilibrium between benzene and toluene at different operating condition. but, the rollup effect on toluene is less than of p and m xylenes and o-xylene. so, the increasing in the concentration of xylenes in the effluent streams is not represented the actual concentration or separation of these component, therefore, the calculation of cumulative adsorption on zeolite and the analysis of effect on adsorption is done for benzene and toluene separation. table 3 breakthrough data for btx at q=0.16 cm 3 /min, m=50gm, and z=34cm table 4 breakthrough data for btx at q=0.35 cm 3 /min m=50 gm and z=34cm time (min) effluent concentration /influent concentration c/co benzene toluene p and m xylenes o-xylene 0 0.000 0.000 0.000 0.000 10 0.000 0.621 1.413 2.538 20 0.225 0.749 1.390 1.806 35 0.273 0.785 1.270 1.428 65 0.355 0.830 1.257 1.245 95 0.382 0.960 1.373 1.349 209 0.467 0.987 1.366 1.290 269 0.435 1.029 1.460 1.557 329 0.524 0.979 1.336 1.406 359 0.590 1.010 1.290 1.335 table 5 breakthrough data for btx at q=1 cm 3 /min m=50 gm and z=34cm time (min) effluent concentration /influent concentration c/co benzene toluene p and m xylenes o-xylene 0 0.000 0.000 0.000 0.000 10 0.237 0.922 1.576 1.759 35 0.319 0.876 1.498 1.559 65 0.528 0.979 1.253 1.320 185 0.566 1.125 1.402 1.443 305 0.612 1.151 1.397 1.437 effect of feed flow rate: tables (3)-(5) show the values of c/co in the different period of time for benzene, toluene, p and m xylenes, and o-xylene at different feed flow rates these data are plotted in figures (2)-(4) as breakthrough curves of these components. these figures indicate that the higher flow rate generally responsible for earlier break points. this is because a high flow rates exhaust the bed more rapidly, the increasing in the flow rate leads to decreasing the contact time between the adsorbate and the adsorbent along the adsorption bed. time (min) effluent concentration /influent concentration c/co benzene toluene p and m xylenes o-xylene 0 0.000 0.000 0.000 0.000 5 0.000 0.325 1.483 1.732 25 0.000 0.437 1.556 1.660 40 0.098 0.644 1.470 1.540 70 0.101 0.665 1.456 1.522 100 0.134 0.757 1.442 1.451 170 0.341 0.719 1.168 1.206 400 0.440 0.840 1.230 1.240 650 0.560 0.980 1.156 1.135 abdul halim a.k. mohammed and maisa mehdi abdul-raheem 17 ijcpe vol.9 no.4 (2008) fig.2: breakthrough curves for adsorption btx at q=0.16 cm3/min and m=50gm the effect of the flow rate on adsorption is noted clearly for benzene and toluene. the flow rate increasing decreases the breakthrough and saturation times. for example, in figures (2)-(4) for flow rate 0.16,0.35, and 1 cm 3 /min benzene reaches the breakthrough concentration c/c0=0.1 at time 40,15, and 5min, respectively. using the same figure and conditions for toluene, at time 10 min the value of c/c0 are 0.53, 0.62 and 0.92, respectively. the short breakthrough time of toluene is because toluene has the higher concentration in the influent stream therefore high driving force between adsorbate and adsorbent was obtained. for determination the capacity of zeolite 13x and the accumulative adsorption (q) gm/gm adsorbent after a given time of adsorption equation 1 was used. q i= (c0-c)/m*q*t ……………..(1) where, qi=the quantity of solute adsorbed per unit mass of adsorbent at any given time, gm/gm adsorbent . c0=initial concentration of adsorbate (benzene and toluene), gm/cm 3 . c=effluent concentration of adsorbate at each time, gm/cm 3 . m=mass of adsorbent, gm. q=volumetric flow rate,cm 3 /min t =time of sample min. the accumulative adsorbed versis time at different flow rate is plotted in figures (5)-(7). these figures indicate that the amount of toluene adsorbed is higher than that of benzene at any time. this is because of the higher driving force for toluene and higher amount in the feed. these figures also show that when toluene reaches the saturation time, q of toluene is reduced and q of benzene becomes higher that toluene. the later phenomenon is due to, zeolite saturation by toluene which leads to the absent of driving force to transfer. fig.5: cumulative adsorption of benzene and toluene q=0.16 cm 3 /min and m=50 gm fig.3: breakthrough curves for adsorption btx at q=0.35 cm3/min and m=50 gm fig.4: breakthrough curves for adsorption btx at q=1 cm3/min and m=50 gm adsorption of btx aromatic from reformate by 13x molecular sieve 18 ijcpe vol.9 no.4 (2008) fig.6: cumulative adsorption of benzene and toluene q=0.35 cm 3 /min and m=50 gm fig.7: cumulative adsorption of benzene and toluene q=1 cm 3 /min and m=50 gm the effect of flow rate on adsorption capacity is shown in figure (8). this figure indicates that the adsorption capacity of zeolite for toluene decreases with the flow rate increasing. this is because the higher rate of toluene adsorption and high flow rate which leads to insufficient times of contact between toluene and zeolite for transfer. so, benzene will have active surface area of adsorbent for transfer and this increase its capacity. fig.8: effect of flow rate on the capacity of zeolite for benzene and toluene effect of bed length the diameter of adsorption column is constant; therefore the used weight of adsorbent corresponds to different bed lengths. data are plotted as breakthrough curves in figure (9)-(11). fig.9: breakthrough curves for adsorption btx at q=0.8 cm 3 /min and m=40 gm abdul halim a.k. mohammed and maisa mehdi abdul-raheem 19 ijcpe vol.9 no.4 (2008) fig.10: breakthrough curves for adsorption btx at q=0.8 cm 3 /min and m=60 gm fig.11: breakthrough curves for adsorption btx at q=0.8 cm 3 /min and m=70 gm thee figures show that the shorter bed lengths are generally responsible for earlier break point. the use of short bed length as in figure (9) leads to shorten the contact time between the adsorbate and adsorbent and reduced the available area to transfer. for example, figures (9)-(11) show that for bed length 29,34 and 45 cm, the benzene reaches the breakthrough concentration c/c0 =0.1at times 1.3 and 4 min., respectively, and for toluene for the same bed lengths, at time 5min the values of c/c0 are 0.746, 0.638, and 0.45, respectively. these results indicate that the increasing in the bed length leads to breakthrough time increase for benzene and toluene. figure (12)-(14) show the plot of these data between cumulative adsorbed (q) against time. these results show that the amount of toluene adsorbed is higher than benzene at any time for different bed length and solute adsorbed increases with bed length increasing for benzene and toluene. fig.12: cumulative adsorption of benzene and toluene q=0.8 cm 3 /min and m=40 gm fig.13: cumulative adsorption of benzene and toluene q=0.8 cm 3 /min and m=60 gm fig.14: cumulative adsorption of benzene and toluene q=0.8 cm 3 /min and m=70 gm adsorption of btx aromatic from reformate by 13x molecular sieve 20 ijcpe vol.9 no.4 (2008) the effect of bed length on the adsorption capacity of benzene and toluene shows in figure (15). the adsorption capacity increases by bed length increasing for benzene and toluene, because the increasing in bed length leads to increasing in the surface area available for adsorption. fig.15: effect of bed length on the capacity of zeolite for benzene and toluene conclusions 1. the strongly adsorbed component (benzene) leads to displace part of weakly component ( toluene and xylene). so, higher outlet concentration of weak component ( xylene) above that of inlet streams was observed. 2. the time of break points increases with flow rate decreasing and bed length increasing for benzene and toluene. 3. the time required to reach the saturation point for toluene is increasing by decreasing flow rate. 4. the capacity of zeolite 13x for adsorption of benzene increases with flow rate increasing. 5. the capacity of zeolitr 13x for benzene and toluene increases with increasing the bed length. reference 1. beveridge, j.,mair and mathu hamaiengar, analytical chemistry, vol.30, no.2, february1958. 2. richards, w., neuzil downers grove, u.s. pat 3,663,638 may 16, 1972. 3. jacobs, p.a., and van santen, r.a., "zeolite facts, figure, further", elsevier science publishing company, inc., new york, 1989 . 4. owaysi et al., u.s. pat. 4,567,315, jan.28,1986. 5. drazaj, b., hocevar, s., and pejovnik, s., "zeolite, synthesis, structure, technology and application", elsevier science publishing company, inc., new york, 1985. 6. kaul et al., u.s. pat 5,186,819, feb. 16,1993 7. kebberkvs, b.b., "enviromental chemical analysis", blackie academic and proffesional, london, 1998. 8. kirk-othmer, "encyclopedia of chemical technology" , vol. 1, john wiley and sons, inc., new york, 3 rd edition, 1983,p.544-563. 9. keller ll, g.e., anderson, r.a., and yon, c.m.,"handbook of separation process technology", wily interscience publishing, new york, 1987. bx من البنزين المحسن ببستخدام المنبخل الجزيئيةbtx) (أمتصبص المركببت االرومبتية الخالصة حى اخخببر . يٍ انزٍفوريَُجbtxٍخعبيم هذا انبحذ يع فصم انًزكببث االرويبحَت و بشكم خبص انبُشول، انخهوول، وانشاٍهَُبث . فٌ انعًود انًحشو13xانفصم ببسخخذاو االيخشاس عبز انًُبخم انجشئَت ببسخخذاو انشٍوالٍج . حى قَبص حزاكَش انًزكببث االرويبحَت فٌ انخَبراث انذاخهت و انخبرجت فٌ انعًود انًحشو ببسخخذاو كزويوحوغزافٌ انغبس . درص حبرَز كم يٍ يعذل جزٍبٌ انًبدة االوٍت و ارحفبع انعًود عهي َوع االيخشاس و سعت االيخشاس نهًُبخم انجشٍئَت وهذِ انًزكببث حًذص فٌ . اٌ يَم انًزكببث االرويبحَت ناليذصبص يٍ انزٍفوريَج هٌ بخذرج انبُشول رى انخهوول ورى انشاٍهَُبث -oساٍهٍَ نذنك ٍحذد اني o ساٍهٍَ، انخهوول ، وانبُشوول وحكوٌ قوٍت االيذصبص يقبرَت يع m و p. اٌ واحذ عُذ بذاٍت انعًهَت انخزكَش . ساٍهٍَ عًهَت حزحَف يٍ انشٍوالٍج و حعطي حزاكَش عبنَت فٌ انًجبرً انخبرجت يقبرَت بخزكَشهب انًوجود ببنذاخم . ساٍهٍَ اعهي يٍ حزكَشهب انذاخم بسبب عًهَت انخشحَف بواسطت انًزكب االقوى قببهبت ايذصبصَت m و pانخبرج dr jassim al-hilo _mag_.doc ijcpe vol.8 no.4 (december 2007) 25 iraqi journal of chemical and petroleum engineering vol.8 no.4 (december 2007) 25 30 issn: 1997 -4884 the production of ethanol from sugar beet waste by immobilized saccharomyces cerevisiae jasim al-hilo, thamir j. mohammed, and rana a. al-naime chemical engineering department university of technology iraq abstract saccharomyces cerevisiae cells were immobilized in calcium alginate beads and activated charcoal for use in the production of ethanol from batch fermentation of sugar beet waste. treatment of the waste with naoh to increase the ability of lignocellulose material to hydrolysis by acid (2n h2so4) to monosaccharide and disaccharide (mainly glucos). the high reducing sugar concentration obtained was equal to 9.2gm/100ml (10brix) after treatment. fermentation parameters, are (ph, glucose concentration (2.5 -25 gm/100ml), immobilized agent concentration (2.5 -25 gm/100ml) were studied to find the optimum physiological condition. and the highest ethanol concentration obtained from the fermentation in the presence of 20%(wt/v) calcium alginate was (9.322%(wt/v)) at 13.75%(wt/v) glucose concentration and ph 5 .the experimental results were correlated by empirical second order polynomial equation with correlation coefficient 96.734% and variance 9 3.574% keywords: sugar beets , ethanol. introduction bioethanol is ethanol (c2h5oh) a colourless liquid with a faint odour [1]. it was produced by biological fermentation of biomass. biomass means vegetable and animal substances consisting of the biodegra dable fraction of products wastes and residues from agriculture, forestry and related activities, or industrial and municipal waste [ 2 ]. the production of ethanol is a world wide industry .it is not only used as an alcoholic spirit but also as pure produ ct in food, pharmaceutical personal care detergents, adhesives, lubricants, it is also used as an intermediate material to produce various products and other industries. a large scale application of bioethanol is it’s use as a transportation fuel. when henry ford in 1907 re-introduced to american motoring public by producing his first vehicle to run on ethanol [ 3 ]. bioethanol can be produced from a range of agriculture feed stocks, such as starch crops, sugar crops, woody crops and sugar industry bioproducts such as sugar cane bagasse, and sugar beet waste [ 4 ]. in the united states, approximately 6.8 billion liters of ethanol were manufactured in1997 from starch . brazil produced 14 billion liters of ethanol from sugar cane in 1997. other countries now developing bioethanol industries include spain, france and sweden in the eu; as well as australia and canada [ 5 ]. the advantage of using sugar beet waste as a substrate for bioconversion are that it has a high carbohydrate content (cellulose 40 -50%, and 20-30% hemicellulose) and a cheap substrate(waste product) cellulose ,a polymer of c6 sugar (glucose) ,hemicellulose aco-polymer consisting of c5 sugar (mainly xylose)and lignin a “random “ polymer consisting of mainly are shown in figure 1. both the cellulose and hemicellulose fraction can be fermented to ethanol after a suitable pre -treatment and hydrolysis steps. the pre -treatment of lignocellulose was necessary for the separation of lignin from structure, usually by steam explosion, dilute acid and dilute alkali, followed by hydrolysis with acid, enzymatic by fungus (trichoderma viride ) and thermochemical process [ 6 ]. university of baghdad college of engineering iraqi journal of chemical and petroleum engineering the production of ethanol from sugar beet waste by immobilized saccharomyces c erevisiae ijcpe vol.8 no.4 (december 2007) 26 the production of ethanol via anaerobic yeast growth may be achieved by using either free or immobilized cell systems, the immobilized yeast-cell system can be defined as any system in which yeast cells are confined within a bioreactor [ 7 ].the principle method, for immobilization were: crosslinking, entrapment, covalent binding, encapsulation and adsorption. the advantage of using immobilized cells were provides of much greater cell concentration, higher conversion of glucose to ethanol and reducing the contamination of the product [8]. figure (1)structure of lignocellulose[ 9 ] experimental work organisms baker`s yeast ( saccharomyces cerevisiae ) of trade mark name yuva ( turkey) was used in this research . raw materials sugar beet waste (sbw) which is produced as of sugar manufacture was used as a basic substrate in all experiments. it was kindly provided in the form of small dry clinders by the sugar factory in mosul / iraq. analysis of sugar beet waste showed the following constituents ( % ) taken from the factory . moisture 8.59%,disccharide (sucrose) 3.5%,monsaccharide (glucose) 0.7%,cellulose 38.6%,hemicellulose 26.5%,lignin 12.1%,protein 8.5%,ash 2.8% . ethanol production media the media was prepared as follows for one-liter of (sbw) extract with certain glucose concentration (nh 4)so4 3.00 gm kh2po4 3.00 gm mgso4.7h2o 0.2 gm cacl2.2h2o 0.2 gm yeast extract 1.0 gm preparation of sugar beet waste in order to prepare the waste, it was powdered with the help of a grinder and passed through sieve analysis apparatus.the size (1mm) is select according to [10] conversion of carbohydrate to sugar 1-pretreatment of sugar beet waste with dilute alkali the following procedure was carried out to delignified the (sbw)[10 ] : a-(100)gm of (sbw) was passed through (1mm)mesh and treated with (0.25m)of sodium hydroxide (500) ml at 70 °c for 2hr. b-the delignified pulp was recovered by filtration and thoroughly washed with distilled water until the washing of neutral ph . c-the washed pulp was stored in moist at 4°c. d-drying the pulp in oven at 40° c. 2-hydrolysis by sulfuric acid the following procedure was followed for the digestion of (sbw) [11 ]. a-[2n] of sulfuric acid was added to pretreatment material by using a solid to liquid ratio of 1:4 . b-the samples were put in autoclave at (121°c ,15 psig ) during(60) min c-the mixture was cooled after filtration. dneutralization with cao powder. e-the concentration of soluble sugar was determined by refractometer fevaporated gently by oven at 40°c to concentrate the solution to 25(%). analytical methods brix value brix value (total soluble solid) of (sbw) extract was measured by placing a drop of solution on the refractometers glass .the apparatus was previously standardized with distilled water. the temperature wa s fixed at 20°c [12]. measurement of ethanol concentration the ethanol concentration was measured by method of analysis of the american society of brewing chemists in yeast culture dependence on specific gravity measurement by using pycnometer [ 12 ]. measurement of the population the number of suspended cells of yeast was calculated by hemocytometer, dilution with sterilized physiological solution (0.9%nacl) was required to obtain the number of cells per ml for free cell process and immobilized cell process [ 13 ]. preparation of inoculum a-dispress (5gm) of baking yeast in one-liter of physiological solution (0.9%nacl) at 25°c. b-shake the yeast suspension in flask by hand vigorously. jasim al-hilo et al ijcpe vol.8 no.4 (december 2007) 27 c-calculate the number of yeast cells in ml.the inoculum a mount was calculated as 6.8*106 cells /ml . immobilized yeast preparation immobilization of yeast in activated charcoal by covalent binding the following procedure was used to prepare immobilized yeast. a-various amounts of activated charcoal were taken (2.5,5.8,11,16,20)gm and added to (100)ml conical flask, then sterilized in an oven at a temperature of 160°c for 90min. b(10 )ml of the yeast slurry with cell suspension (6.8*106) cell/ml was mixed with activated charcoal for 24 hr at room temperature to ensure complete mixing [ 14 ]. c-the charcoal was collected by filtration, washed with (100 )ml of cooled distilled water and left to dry [ 8 ]. d-the immobilized yeast was stored at (4-8)°c until required to work [ 13 ]. immobilization o f the yeast in calcium alginate by entrapment the following procedure was used to prepare immobilized yeast [ 13 ] a4gm sodium alginate were dissolved in (100)ml physiological solution (0.9% nacl).the dissolving process of sodium alginate in water was slow so that it required speeding up by warming the solution gently. the solution was then autoclaved at 121°c for 15min under 15 psig . b-tewenty conical flasks of (500) ml were provided with (300) ml calcium chloride (cacl2.6h2o) solution in concentration (0.15m) and then autoclaved at 121°c for 15min under 15 psig. c-(10)ml of spore suspension were added to the solution prepared in step (a) and dissolved with volumes of sodium alginate solution (1.15,3.768,6.377,8.986,11.515) ml which were equivalent to weights to (2.5,5.8,11,16,20)gm and the mixture was stirred to ensure complete dissolution . d-the spore /na alginate solution was then added dropwise (with syringe) with stirring to a (0.15 m ) cacl2 solution. the gel beads formed were left in solution for 1 hr before being filtered off. the beads were then washed with (100)ml distilled sterilized water (0.9%nacl)for 20min to allow the diffusion of excess calcium . results and discussion effect of ph the ph has a significant influence on fermentation due as much to its important controlling bacterial contamination as to it is effect on yeast growth, fermentation and by product formation, therefore maintenance of ph is of paramount importance in fermentation processes, the efficiency of the yeast strain was evaluated in the ph rang (3.85-5.3) above ph = 5.3 due to decrease with increasing ph .the experimental results are show in figures 2&3. figure 2 shows the influence of ph on ethanol concentration the various concentration of glucose (2.5-25%(wt/v) in the presence of 20%(wt/v) activated charcoal .it is obtained that ethanol concentration increases with increasing ph till it reach to 5.3, at this point the value of ethanol concentration is equal to 8.85%(wt/v) at 13.75 %(wt/v) glucose concentration.then it decreases with increasing ph where it reach to 7, at this point value of ethanol concentration is equal to 7.301%(wt/v).figure 3 shows the influence of ph on ethanol concentration the various concentration of glucose (2.5-25%(wt/v) in the presence of 20%(wt/v) calcium alginate. it is observed that ethanol concentration was increases with increasing ph .the maximum ethanol concentration can be obtained is 9.22%(wt/v) at ph 5.18 and 13.75%(wt/v) glucose concentration , then it decreased to 8.332%(wt/v) at ph 7. figure (2) effect of ph on ethanol concentration at different glucose concentrations in the presence of 20%(wt/v) charcoal figure (3) effect of ph on ethanol concentration at various glucose concentrations in the presence20% calcium alginate 0 2 4 6 8 10 2.5 3.5 4.5 5.5 6.5 7.5 ph e th a n o l c o n c e n tr a ti o n (w t/ v )% c=2.5% c=7.25% c=13.75% c=20.25% c=25% 0 2 4 6 8 10 2.5 3.5 4.5 5.5 6.5 7.5 ph e th a n o l c o n c e n tr a ti o n % (w t/ v ) c=2.5% c=7.25% c=13.75%" c=20.25% c=25% the production of ethanol from sugar beet waste by immobilized saccharomyces c erevisiae ijcpe vol.8 no.4 (december 2007) 28 effect of glucose concentration the results shown in figures4& 5. these figures show the influence of glucose concentration in the range (2.5-25%(wt/v)) on the ethanol concentration at various values of immobilized agent and optimum ph . the results obtained indicated that the ethanol concentration increases with increasing substrate concentration till it reaches 16.14%(wt/v). at this concentration the ethanol concentration is equal 8.812%(wt/v) at ph 5.3 and 20%(wt/v) activated charcoal, then it reduced to 5.876%(wt/v) at 25%(wt/v) glucose concentration and 20%(wt/v) activated charcoal. in the presence of the optimum value of ph 5.18 the ethanol concentration increased with incre asing glucose concentration at different values of calcium alginate concentration in the range (2-20%(wt/v)) shown in figure (5). (4.453 %(wt/v)) was obtained at 2.5%(wt/v) glucose concentration and 20%(wt/v) calcium alginate then it increased with increas ing glucose concentration till it reached 16.442%(wt/v), at this concentration the ethanol concentration was equal to (9.3176%(wt/v)) in the presence of 20% calcium alginate and ph 5.18, then ethanol decreased with increasing glucose concentration where it reached 25% (wt/v). at this point the ethanol concentration was equal to (7.112%(wt/v)) at 20%(wt/v) calcium alginate and ph 5.18. the above results show that the optimum concentration of glucose for ethanol production is (16.14 ,16.442%(wt/v))for activated charcoal and calcium alginate respectively then the above of these concentrations due to decrease of production of ethanol . figure (4) effect of glucose concentration on ethanol concentration at different value of activated charcoal concentration in the presence of ph 5.3 figure (5) effect of different glucose concentration and different value of calcium alginate concentration on ethanol concentration at ph 5.18 effect of immobilized agent figures 6 & 7 clarify the effect of immobilized agent concentration (2-20%(wt/v)) on ethanol concentration at various values of ph and optimum concentration of glucose. figure 6 shows how the activated charcoal concentration affects on the ethanol concentration at different ph . it was indicated that the ethanol concentration increases with increasing activated charcoal, where it rises from 4.684%(wt/v)at 2%(wt/v) activated charcoal, ph 5 and glucose concentration 16.14%(wt/v) to 8.8992%(wt/v) at 20%(wt/v) activated charcoal, ph 5 and glucose concentration 16.14%(wt/v) .the influence of different concentrations of calcium alginate at different value of ph at optimum value of glucose concentration is shown in figure 7. figure(6) effect of activated charcoal at various v alues of ph on ethanol concentration and 16.14%(wt/v) glucose concentration 0 2 4 6 8 10 0 4 8 12 16 20 24 28 concentration of glucose %(wt/v) e th a n o l c o n c e n tr a ti o n % (w t/ v ) i=2% i=5.8% i=11% i=16% i=20% 0 2 4 6 8 10 0 5 10 15 20 25 30 concentration of glucose%(wt/v) e th a n o l c o n c e n tr a ti o n ( w t/ v )% i=2% i=5.8% i=11% i=16% i=20% 0 1 2 3 4 5 6 7 8 9 10 0 5 10 15 20 25 activated charcoal %(wt/v) e th a n o l c o n c e n tr a ti o n ( w t/ v )% ph=3 ph=3.845 ph=5 ph=6.15 ph=7 jasim al-hilo et al ijcpe vol.8 no.4 (december 2007) 29 it is obtained that ethanol concentration was increased from 5.423%(wt/v)at 2%(wt/v) calcium alginate ,ph 5 and 16.442%(wt/v) glucose concentration to 9.223%(wt/v) at 20%(wt/v) and same ph 5. from the above results it might suggested that the ethanol concentration increases with increasing immobilized agent concentration. figure(7) effect of calcium alginate on ethanol concentration at different values of ph and 16.442%(wt/v) glucose concentration effect of time in fermentation reaction, inoclum time is very important in obtaining maximum ethanol production with minimum time. figure 8 shows the effect of time on ethanol concentration at 13.75%(wt/v) glucose concent ration, ph 5 and 11%(wt/v) immobilized agent concentration. it was found that the ethanol increases with increasing time, from 7.52%(wt/v) after 1 day to (8.85%(wt/v)) and (9.11%(wt/v)) after 4 days and remains relatively constant after 5 days on for activated charcoal and calcium alginate respectively. figure (8) effect of time on ethanol concentration at 13.75% glucose , ph 5and 11% immobilized agent ghanim (1992) found that the ethanol concentration remains relatively constant after four days from glucose by using activated charcoal to immobilized s.cerevisiae [ 14 ]. the difference in results may be due to inoculum amount. it is a very important factor.after the particular cell density is reached to growth phase slowly and the life cycle of the yeast deviates from the growth path and produces ethanol. if the cell density is less, more time will be taken for the production of ethanol by fermentation reaction [15]. effect of shaking figure 9 shows the influence of glucose concentration on ethanol concentration at constant operating condition 30°c, ph 5, and11% immobilized agent concentration, were cultivated under aerobic conditions in shaker incubator. it was obtained that ethanol concentration increases with increasing glucose from (4.06,4.28%(wt/v)) at 2.5%(wt/v) glucose concentration to (9.11,9.35%(wt/v)) at 13.75%(wt/v) glucose concentration, then it reduced to (7.11,7.32%(wt/v)) at 25%(wt/v) by using activated charcoal and calcium alginate respectively. in comparison in still culture it was found that increase of ethanol concentration at the same operating condition were cultivated in shaker incubator because this process do under aerobic condition . figure (9) effect of glucose concentration on ethanol at constant ph 5,30°c ,11% immobilized agent in shaker incubator. figure (10) effect of glucose concentration on ethanol at constant ph 5,30°c ,11% immobilized agent in (without shaking). 0 2 4 6 8 10 0 5 10 15 20 25 calcium alginate %(wt/v) e th a n o l c o c e n tr a ti o n ( w t/ v )% ph=3 ph=3.845 ph=5 ph=6.15 ph=7 4 5 6 7 8 9 10 0 1 2 3 4 5 6 7 time (day) e th a n o l c o n c e n tr a ti o n % (w t/ v ) act.charcoal ca-alginate 0 2 4 6 8 10 0 4 8 12 16 20 24 28 concentration of glucose %(wt/v) e th a n o l c o n c e n tr a ti o n % (w t/ v ) act.charcoal ca.alginate 0 2 4 6 8 10 0 4 8 12 16 20 24 28 concentration of glucose (wt/v)% e th a n o l c o n c e n tr a ti o n ( w t/ v )% act.charcoal ca-alginate the production of ethanol from sugar beet waste by immobilized saccharomyces c erevisiae ijcpe vol.8 no.4 (december 2007) 30 empirical correlation the experimental results of ethanol concentration production as a function of ph, glucose concentration and immobilized concentration by second order polynomial are y=b0+b1*x1+b2*x2+b3*x3+b4*x1^2+b5*x2^2+b 6*x3^2+b7*x1 *x2+b8*x1*x3+b9*x2*x3 where : x1= ph x2=glucose concentration x3=immobilized concentration conclusions the experimental study of the ethanol production from sugar beet waste extract by immobilized cell fermentation has given some basic information. in general, the following conclusions are drawn from the present study: 1-the highest amount of reducing sugar can be obtained by pre -treatment of (sbw) with naoh that increases the solubility of sugar, and also hydrolysis by h2so4 (2n) at 121°c, 15 psig for 60 min produce 10brix of sugars (mainly glucose) . 2-increasing glucose due to the increase of ethanol concentration till it reaches the optimum value and above the optimum value decreases the ethanol concentration the optimum concentration of glucose at maximum ethanol concentration for each immobilized cell (activated charcoal, calcium alginate) are ( 16.14, 16.442 %(wt/v)) respectively. and the optimum ph of ethanol concentration for immobilized cell (activated charcoal ,calcium alginate ) were between (5.18-5.3). 3-ethanol concentration increase with increasing immobilized agent concentration. the optimum immobilized agent for ethanol concentration for two types is equal to 20%(wt/v). and calcium alginate was the best immobilized agent compared to activated charcoal with respect to ethanol production. references 1ecos, a.j.and courier, m. (2003). “ethanol for the australian motorist”., cane growers, australia.1-4 .w: www.canegrowers.com.au.(internet) .pdf 2budget, c.and e.budget. (2004).”ce27 hydrocarbon oils: introduction of a reduced rate of duty on bioethanol “. http: //www.hmce.gov.uk/., 1 -2.(internet).pdf 3-trehan, k (1982).”biotechnology “ chap.3: fermentation biotechnology “ 31-33 4-lynd, n.r.(1992) “review of the research strategy for biomass –derived transportation fuels “.,the national academies press, london pp5-10. 5-ethanol industry .(2000) /http://www.bioproducts – bioenergy .gov/. 6-how agriculture can contribute to a better environment. (2004) /http://www.cope-cogeca.be/. 7-kirsop, b.e and kurtzman, c, .p.(1988) “yeasts”;cambridge university press .australia. 8-bickerstaff, g.f. (1997). ”immobilization of enzymes and cells “.,human press ,totowa ,new jersey : 1 -367 . 9-shleser, b.(2002).”ethanol from sugar cane and other biomass “the aina institute for bioconversion technology. hawaii:1 -23. 10-dekker, r.f.h. and wallis, a.f.a.(1983) .”enzymatic scarification of sugar cane bagasse pretreated by autohydrolysis -steam explosion,”biotechnology and bioengineering, john wiley and sons, inc.vol.xxv,3027-3048. 11-badger, p.c.(2002) ethanol from cellulose :ageneral review .p.17-21.in:janick ,j. and whipkey, a.(eds.), trends in new crops and new uses .ashs press ,alexandria,va. 12-noaman, r.m., (1999), ”preparation of glucose by enzymatic hydrolysis of starch pharmaceutical uses”, m.sc, university of technology 13-schmauder, h.p.(1997).”methods in biotechnology “.,taylor and francis,norwich,uk.:1-257 . 14-majeed, g.h.(1992) “a study on ethanol production by bakers yeast s.cerevisiae by batch culture and immobilized cells” m.sc.thesis. baghdad university.college of science . 15–pramanik, k. (2000).” parametric studies on batch alcohol fermentation using saccharomyces yeast extracted from toddy “., chemical engineering ,andhra pradesh ,in dia :1-10 . available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.19 no.3 (september 2018) 1 – 9 issn: 1997-4884 corresponding authors: arwa raad ibrahim, email: chemicaleng89@yahoo.com, basma abbas abdulmajeed, email: basma1957@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. biological co-existence of the microalgae – bacteria system in dairy wastewater using photo-bioreactor arwa raad ibrahim and basma abbas abdulmajeed department of chemical engineering, college of engineering, university of baghdad abstract aeration system in the cultivation of chlorella sp. microalgae using dairy wastewater as culture media was addressed in the current study. this research aimed to study the effect of aeration in the bubble column bioreactor on the biological synergy between microalgae and bacteria if they are present in the same place. the results show that the sterilization stage is not the dominant step in the success of microalgae cultivation in water-rich organic waste. there is a clear convergence between the growth rate of chlorella microalgae in the sterilized and non-sterilized culture media, which gives realism if the proposal is applied industrially. through the information obtained the aerobic bacteria in the non-sterilized media, with free of algae, are able to consume all dissolved oxygen within a very short period of time. the aeration factor is, therefore, important in that case. however, the experiments show that coexistence of bacteria and microalgae can occur even if there is no aeration system. consequently, the microalgae in the dairy wastewater are capable of preserving the environment of cultivation. the gases produced due to metabolic processes in bacteria or microalgae remain in solution for a certain period and are not easily removed, especially if the solution is exposed to intermittent sparging. thus, this will give enough time for both microorganisms to consume those gases. however, the results show that the sparging system for 15 minutes and three times a day improves biomass production by 60%. therefore, the cultivation of microalgae in addition to its desired goal can play an important role in the dairy wastewater treatment units by maintaining the appropriate environment for aerobic bacteria even in the absence of an aeration system. keywords: chlorella, aeration, photobioreactor, microalgae received on 01/04/2018, accepted on 30/05/2018, published on 30/09/2018 https://doi.org/10.31699/ijcpe.2018.3.1 1introduction 1.1. background of the problem identifying the biofuel as alternative sources of conventional fuels has become a scientific concept. however, those sources, with their high costs or lower production, to be an ideal substitute for fossil fuels are still illogical topic ‎[1], ‎[2]. crops source, as an example, is in a competitive position with global food demand ‎[3]‎[5]. in fact, biofuel produced from this source require large areas of arable land with water for cultivation purpose ‎[6]. in addition, these crops can meet the needs of some countries to prevent famine ‎[7]. recently, the microalgae source was considered as best chose to deal with environmental problems and greater productivity of biofuel than other sources ‎[1],‎[8],‎[9]. from an economic perspective, microalgae are an important source of many products. energy, chemicals extracted, food, and healthcare constituents are the most important products that are available from those organisms ‎[10]. compared with biofuels produced from agricultural crops, the source of microalgae is less expensive and more productive than other sources, and above all does not cause a problem in the global food crisis ‎[11]. based on some studies, half of their dry weight is oil content that can be extracted to be an environmentally friendly fuel and a good alternative to fossil fuels ‎[1]. however, the growth requirements are still obstacles to achieving that goal ‎[12]. the nutrients, an example of these requirements, are one of the main necessary for living the microorganism. the difference in nutrient quality depends on the type and nature of the organism that will consume it. in general, phosphorogenic and nitrogenous compounds are considered to be the most important elements for the growth of microorganisms, including microalgae. while, carbon source can be obtained from the carbon dioxide or from carbonic compounds that found in the media. however, there are other essential compounds that can improve the number of products such as micronutrients ‎[13]. the most commonly known nutrients in the cultivation of microalgae are chu’s medium no. 10 and bg11 broth ‎[14]. they are standard solutions containing phosphates and nitrogen as main compounds as well as other mineral salts. through the complex structure of these solutions, they are a cost factor that increases the cost of producing microalgae. https://doi.org/10.31699/ijcpe.2018.3.1 a. r. ibrahim and b. a. abdulmajeed / iraqi journal of chemical and petroleum engineering 19,3 (2018) 1-9 2 despite the relentless attempts to find alternatives to those standard nutrients that are supposed to be available and less expensive, these proposed solutions need to be studied, developed and applied reasonably ‎[15]. it is known that the development of industries still produces a large quantity of wastewater. in addition to its contribution that is already facing energy problems, the resulting wastewater and its environmental pollutants have become an obstacle to these developments. these pollutants are related to human health. thus, it has become necessary to use applied studies to address industrial problems and minimize energy requirements. this is accomplished by identifying the most efficient means of exploiting bio-energy sources to provide the necessary energy. nevertheless, that process, if accompanied by the improvement of the source itself, it will be increased the benefits to the maximum extent possible. in the food industry, as an example, the amount of wastewater produced from these processes has increased significantly recently. this increase requires numerous physiochemical, and biological treatment to control contaminants. despite the evolution of these processes, high costs and inefficiency still remains the main obstacle to the development of these processes. on the other hand, there is a loss of organic matter exist in untreated wastewater. these materials, if utilized, will achieve significant economic benefits as well as contribute to reducing processing costs. there are several studies that have included the cultivation of microalgae in dairy waste ‎[16]-‎[18], but the operating conditions, microalgae species, and type of study case may differ from research to another. in order to cost-effective, the current study sought out to be close to the possibility of application industrially through moving away from the complexities or the addition of other industrial units. 1.2. sterilization challenge the sterilization stage enables the cultivation of a certain type of microalgae in isolation from other organisms, along with food and their suitable operational conditions, especially if the microalgae were cultivated in standard media. this media usually contains precise compounds and nutrients that suitable for certain species of organisms. but, using alternative culture media, may contribute to the wideness of living organisms that can grow as soon as they are exposed to the atmosphere if the appropriate operating environment is available. therefore, a need to sterilization stage represents an important step ‎[19]. sterilization is done using high temperatures (121 ° c) and pressure of about 2 bar for 15 minutes using autoclave device. thus, application of cultivation of microalgae industrially with huge amounts of biological media may be impractical and adds considerable economic cost. previous studies have addressed the subject as with the ding ‎[20], but its use of the principle of dilution models needs to lose large amounts of water. in dairy factories, the pasteurization, chilling, and homogenization are processes used in manufacturing the butter, cheese, and milk ‎[21]. these processes produce wastewater with a high level of chemical and biological oxygen demand, thus it gives a clear idea of the amount of food enriched in those wastes (i.e eutrophication). during the manufacture of these food products, large quantities of water are used to complete the manufacturing process. as a result, the used water contains large amounts of fat, proteins, and sugars, which are nutrients for the growth of a huge group of microorganisms, including aerobic bacteria. discharge the dairy wastewater into the river without biological treatment would inevitably cause a major economic problem and hazardous to the environment. in fact, its negative impact will not only be on humans but on fish and marine resources as a result of the consumption of oxygen from the bacteria that will feed on those wastes. the current research addressed this problem seriously by verifying the cultivation of microalgae in dairy wastewater in the case of sterilization using the autoclaves and comparing the results with that obtained from the cultivation of the same algae in non-sterilized wastewater. then, the biological synergy between microalgae and bacteria was investigated in dairy wastewater using bubble column bioreactor. 2experiments and methodology 2.1. experimental setup for sterilization study three farms were established in the current study with a size of 500 ml flask. incubator with a temperature controlled by 30 ° c as the optimum temperature was used for this culture. all the experiments were carried out with cool white fluorescent light. one millilitre of microalgae inoculums was placed in each flask with handshaking periodically. while the sampling was taken every two days to give enough time to reproduce. 2.2. experimental setup for biological synergy study two cylindrical photo-bioreactors with a diameter of 120 mm and 260 mm height were constructed for the current study as shown in fig. 1 and fig. 2. one of the bioreactors was provided by a ceramic diffuser (diameter 80mm) for sparging system purpose. this experimental set-up was used to grow microalgae in non-sterilized dairy wastewater. one of these bioreactors was aerated with a 500 ml/liter, while the second reactor was left without ventilation for comparison purposes. the aeration system was carried out for 15 minutes with three times a day separated by one stopwatch without aeration. according to initial experiments, this sparging period is sufficient to dissolve the oxygen level of equilibrium. a. r. ibrahim and b. a. abdulmajeed / iraqi journal of chemical and petroleum engineering 19,3 (2018) 1-9 3 temperatures in both reactors were controlled at 30 °c, while dissolved oxygen and ph were monitored daily. the lighting process was carried out via cool-white fluorescent (t5 led, china). the light intensity was 110.6 µe m -2 s -1 , which was measured using light intensity meter (milwaukee sm700, italy). microalgae growth rate was confirmed by the optical density in the first part of the study and by dry biomass weight in the second part. the density of the biomass was calculated using the wavelength of 680 ‎[22]. the biomass weight was obtained using standard methods by separating the microalgae from the solution by centrifugation (5000 rpm) and then drying it for 24 hours, then drying it for one hour in the oven at 60°c ‎[23]. the standard media used in the current study was bg11(himedia m1958). table 1 shows the ingredients of this media with their amount. table 1. bg11 media composition ingredients amount g/l sodium nitrate (nano3) 1.5 dipotassium hydrogen phosphate (k2hpo4) 0.04 magnesium sulphate, heptahydrate (mgso4) 0.075 calcium chloride dihydrate 0.036 citric acid 0.006 ferric ammonium citrate 0.006 edta, disodium salt 0.001 sodium carbonate 0.02 trace metal boric acid (h3bo3) 2.86 manganese chloride, tetrahydrate 1.81 zinc sulphate, heptahydrate 0.222 sodium molybdate, dihydrate 0.39 copper sulphate, pentahydrate 0.079 cobalt nitrate, hexahydrate 0.0494 fig. 1. schematic diagram of the control photo-bioreactor and sparged photo-bioreactor fig. 2. screenshot of the experimental set-up used in the present study 2.3. characteristics of the dairy wastewater the current experiments have been preceded by many initial experiments using standard solutions and dairy wastewater. the samples were taken from the general company for food industry in abu ghraib city. the dairy wastewater was analyzed to measure the total nitrogen (tn), total potassium (tk), and total phosphate (tp) as requirements nutrients for the cultivation of the microalgae as well as chemical oxygen demand (cod). it was found that the total nitrogen, total potassium, total phosphate, and chemical oxygen demand are 1000, 18000, 6000, and 2083 mg/l respectively. the first three parameters were measured in were measured in the department of water and environmentscience and technology laboratories. a. r. ibrahim and b. a. abdulmajeed / iraqi journal of chemical and petroleum engineering 19,3 (2018) 1-9 4 2.4. collection of microalgae strain chlorella microalgae were taken from the department of biological sciences at the university of baghdad. the isolation of these microalgae was done using a continuous dilution method ‎[24], to obtain pure isolates. these strains were maintained using standard methods for keeping and prevent any contamination during the keeping process. the specific growth rate of microalgae was calculated in exponential phase and according to the following equation ‎[25]: (1) where x is dry weight biomass (mg), is specific growth rate (day -1 ), and t is generation time. integrate: ∫ ( ) ∫ (2) while the doubling time was estimated via the following equation: (3) where td is doubling time (day) 2.5. dissolved oxygen measurement the measurement of dissolved oxygen ratio was necessary for the current research to determine the activity of microalgae in dairy wastewater water. the measurement was carried out by using a dissolved oxygen device (oxi 45+, crison, spain). before using this device, it was calibrated and activated according to the procedure of provided company. 2.6. turbidity meter the relative clarity of the media after the agriculture process was determined by the turbidity meter. this device was used to measure the scattering of micro-algae particles in the seed solution. therefore, the turbidity meter that has used in current investigation is turbidity meter (turbdirect, lovibond). 3results and discussion 3.1. sterilization effect three types of biological solutions were used for cultivating the chlorella sp.; sterilized, non-sterilized dairy wastewater and standard media bg11. the cultivation period was carried out by two stages. the first one was cultivation without adjusting the ph during 16 days operating. while in the second stage; the ph was adjusted every two days as can be seen in fig. 3. fig. 3. cultivation of microalgae in sterilized wastewater, non-sterilized wastewater, bg11 through two stages according to this figure, it is noted that the growth rate of chlorella microalgae in sterilized and non-sterilized wastewater is almost close. however, the growth rate in the sterilized solution is more stable than that in the non-sterilized solution. while the growth rate of the chlorella microalgae in the standard solution was somewhat slow. the main reason is that adding 1 ml of inoculums of chlorella microalgae was not enough to sense the growth rate and thus may need more time to grow. in previous studies ‎[25], 15 ml was added to 350 ml media culture. but in the present study, it was noted that adding the current mount (i.e 1:500 ml) of inoculums in dairy wastewater gives a significant growth rate of microalgae. fig. 4 displays the ph values in the three cultivate solutions during the two phases. the figure shows clearly that the ph value of all the models goes up during the microalgae growth period. this increase was due to the reduction in dissolved carbon dioxide in these culture media. however, aerobic bacteria that can be originally grown in these wastes (whether sterilized or non-sterilized), may contribute significantly to the provision of carbon dioxide to the medium. this is because of the availability of materials for growth with the appropriate environment. nevertheless, the ph values of the sterilized media are greater than that of non-sterilized media depending on the amount and activity of the bacteria present in the media. in addition, the values of ph in standard solution are the highest compared with other cultures mediums. the reason is the presence of aerobic bacteria in the wastewater and reducing them in the standard solution, if not already exist. thus, the consumption of carbon dioxide will not have opportunities to be compensated by another source. in case of poor bacterial performance, the ph value begins to rise. therefore, there is a close relationship between the activity of bacteria and ph value if there is an opportunity for the growth of microalgae active in the same media, since the microalgae, in general, is a good consumer of carbon dioxide. a. r. ibrahim and b. a. abdulmajeed / iraqi journal of chemical and petroleum engineering 19,3 (2018) 1-9 5 fig. 4. ph values in sterilized wastewater, non-sterilized wastewater, bg11 through two stages measuring dissolved oxygen in samples is necessary to give a clearer idea of the effectiveness of microalgae. it is evident from fig. 5 that the dissolved oxygen in the nonsterilized media during the first 16 days is the lowest compared to its measurement in the other culture media. this is due to the presence of aerobic bacteria in the biological medium, which initiates metabolic activity very quickly if the appropriate operating conditions exist. in the second stage and during the same experiment, the high ph value was adjusted in all models periodically (every two days) to give sufficient time for microorganism and know the effect of the ph on the growth of chlorella microalgae. fig. 5. dissolved oxygen in the sterilized wastewater, nonsterilized wastewater, and standard solution bg11 the adjusting was carried out by adding 1 m of hydraulic acid to reduce the ph to 7 as shown in figure 4. it can be seen in the same figure that the ph in all culture media and after 24 hours is returned to its original value. but its return to the standard solution is higher than that in other media. fig. 3 shows also a significant increase in microalgae growth rate in all culture solution after adjusting the process. this reflects the impact of ph on growth of microalgae. thus this indicates that enhancement in growth rate can also occur if the ph is maintained around 7. this improvement was due to the convenient environment not only for microalgae but also for aerobic bacteria [26]. nevertheless, reducing the ph reduces carbon dioxide solubility from the atmosphere. but, the presence of the main biological source (carbon dioxide of the bacteria) as well as of the carbonic compounds ‎[27], ‎[28] is already present in the solution is sufficient to compensate for that decrease. however, adjusting the ph by adding hydraulic acid may be a cost factor, and illogical for the application. therefore the use of carbon dioxide in the process of adjustment is better economically and environmentally as well as an adequate amount of carbon for metabolic processes. nevertheless, in the presence of microalgae and bacterium together in the same biological solution, the sparging of carbon dioxide may have a negative impact on aerobic bacteria with the encouragement of nonaerobic reactions to occur in acidogensis anaerobic bacteria by converting the propionate and butyrate to acetate as the following ‎[29]. → (4) → (5) or via methanogenesis anaerobic bacteria by converting carbon dioxide and hydrogen to bio-methane ‎[30], ‎[31]. ↔ (6) effect of ph on microalgae growth rate has been verified in previous studies. among these investigations, are those conducted by khalil ‎[32] and çelekli ‎[33]. they confirmed that the selection of the best-operating conditions of microalgae depends mainly on the type of microalgae that requires growing. some achieve their highest growth rate at ph 9 and others from ph 7. in both cases, with achieving this preference, the biological composition of algae itself can be also changed; such as protein and carbohydrates. moreover, the biological and chemical composition of the solution used in agriculture can play an important role in determining these preferential values. for example, çelekli and dönmez ‎[33] have shown that salinity influences the determination of the best acidity value that produces the best growth. notwithstanding, they display that the ph 7 is possible to achieve that advantage. nevertheless, these researchers were conducted when the growth of one or two types of microalgae in the standard bio-solution. while in the current study the foodrich waste was used as a culture media, which is radically different. the risk of this eutrophication greatly helps the growth of other microorganisms, which can directly or indirectly affect the microalgae growth. a source of biological carbon produced from bacteria plays an important role in determining the optimal operating conditions for microalgae. a. r. ibrahim and b. a. abdulmajeed / iraqi journal of chemical and petroleum engineering 19,3 (2018) 1-9 6 if microalgae lost that important source, they will have to change their pathway depending on the carbon sources found in the carbon as part of the heterotrophic process ‎[34]. according to this study, the biomass produced by the hydrothermal process is much less than that produced by the photosynthesis process. in addition, the dependence on carbon dioxide in the atmosphere without aeration is impractical, since the quantity itself is few, as well as the limits of the mass transfer. it is therefore noted that ph-adjusting has achieved growth rate for microalgae in both culture media (sterilized and non-sterilized). the other evidence is an increase in the concentration of dissolved oxygen in the non-sterilized solution in the second stage, which indicates the rapid growth of microalgae. in fact, and through a series of experiments, it was observed that microalgae in the non-sterilized media undergo an anaerobic phase that may produce hydrogen sulphate or hydrogen. however, after the ph adjustment and activation of microalgae, the produced oxygen completely cut the pathway to continue the anaerobic bacteria. therefore the present study suggested using the sparging system with air instead carbon dioxide to adjust ph and activation of aerobic bacteria and prevent anaerobic bacteria to grow. 3.2. aeration system in microalgae culture effect of aeration system on microalgae growth rate with standard solutions was investigated by almashhadani and khudhair ‎[25]. these solutions (standard solution) contain certain macronutrients and micronutrients suitable for the microalgae growth. thus, this effect may be a positive factor to improve the growth of microalgae due to stripping the dissolved oxygen produced by metabolic processes of microalgae and adjusting the ph value. in the current research, the scenario is different, since the culture media used as a biological solution is dairy wastewater, which is characterized by a food-enriching media. it is, therefore, susceptible to the growth of many microorganisms if their environmental conditions are met. thus, these organisms coexist with the growth of microalgae, which may force them into food competition or sometimes change their environment. the present research gave preference to the non-sterilized solution on sterilized media (as was concluded in the previous section) depending on the economic and applied requirements of the water treatment plant. in addition, it gave an advantage to the growth of microalgae and beneficial aerobic bacteria on other microorganisms as key targets. this can be achieved by making the environment favorable to the desired organisms and controlling the growth of other undesirable microorganisms. thus, the presence of a third factor in controlling the desired path became necessary at this stage. through our investigation with mass transfer of oxygen gas in distilled water and wastewater, it was found that the physical properties of solution play an important role in the dissolution process. fig. 6 shows the dissolution of oxygen in the distilled water and dairy wastewater when the bioreactor was sparged by air. this response was recorded when the solutions were free of microalgae. it can be seen that the dissolution of oxygen in distilled water is higher concentration and quicker than that with dairy wastewater. approximately 2 minutes was required to get 7 mg/l oxygen concentration in distilled water, while 15 min gave about 5.7 mg/l oxygen concentration in wastewater. fig. 6. dissolved oxygen in the distilled water and dairy wastewater in the sparged bioreactor the removal of gases from the solution required more time than from dissolution process. according to our previous experiments, the results showed that the volumetric mass transfer coefficient (kla) of the dissolution of oxygen gas in distilled water was about 3.18 min -1 , while in the removal process using the nitrogen the kla was about 1.67 min-1. the same thing was observed with the dissolution of oxygen and carbon dioxide in water. however, the chemical reactions of carbon dioxide with water for producing of carbonic acid and ions the dissolution and removal processes took longer time than that with oxygen. in fact, this behavior gave a sufficient time advantage to bacteria and the microalgae for the consumption of biogas resulting from the metabolic processes (i.e mutually beneficial). therefore, the aeration system using air to achieve the required path is the factor proposed in this study. two reactors were used in this section, one with a sparging system, while the second one was adopted as a control for comparison. both reactors were operated with a non-sterilized solution with control and monitoring system of temperature, while ph and dissolved oxygen were monitored regularly. fig. 7shows the dry biomass weight during the growth stages of the two reactors. the figure shows the accelerated growth rate in the sparged reactor compared to its growth in the control bioreactor. a. r. ibrahim and b. a. abdulmajeed / iraqi journal of chemical and petroleum engineering 19,3 (2018) 1-9 7 while fig. 8 shows snapshots of chlorella sp. microalgae in the sparged photo-bioreactor and unsparged photo-bioreactor. fig. 7. biomass dry weight of chlorella microalgae in the sparged and unsparged photobioreactor fig. 8. snapshot of chlorella sp. microalgae in the sparged photo-bioreactor and unsparged photo-bioreactor the specific growth rate of chlorella in the sparged bioreactor was 1.2 per day, while its value in control bioreactor was 0.2 per day. moreover, the doubling time was 0.5776 day in a sparged bioreactor, while it was 3.465 day in control bioreactor. these values gave a clear idea of the importance of ventilation for microalgae if they were grown with aerobic bacteria in dairy wastes. in fact, the bubbling of air in the dairy wastewater used as a culture media in the current study contributes to reducing the ph value of the solution as shown in fig. 9. fig. 9. ph value recorded during the sparging the microalgae cultivation the figure also shows the ph readings during the chlorella sp. microalgae cultivation process in this solution over a 15 minute pumping period. increasing the pump period does not necessarily mean a constant decrease in ph. this reduction was the result of carbon dioxide in the air that reacts with water producing two atoms of hydrogen ions. because of its insignificant proportion (i.e co2) in the bubble air, it is unable to increase its concentration more than equilibrium concentration. in fact, the increasing in the carbon dioxide concentration in air increases that equilibrium concentration. this can also occur if the concentration of oxygen in the culture media is higher than its equilibrium concentration. this increase is possibly achieved if the growth of microalgae has increased over the growth of bacteria in the same solution. therefore, the air sparging in the bioreactor may create an opportunity to decrease the concentration of oxygen in the solution as a result of moving of oxygen from the high concentration in the solution to the low concentration in the bubble air until to equilibrium concentration of oxygen based on the fundamentals of the mass transfer. fig. 10 shows the air sparging in the seeding solution and during the cultivation of microalgae has caused a sharp drop in the concentration of oxygen in the solution to settle to 7.63 after 4 seconds. in simple calculations, the equilibrium concentration of oxygen in the distilled water is supposed to be 7.54 at 30 ° c, while these experiments gave slightly higher value because of the different properties of the dairy wastewater to give a small percentage difference. fig. 10. the oxygen concentration in dairy wastewater during the sparging the microalgae 4conclusions biological synergy for chlorella microalgae and aerobic bacteria in the dairy wastewater was investigated in the present study. the convergence of results between the sterilized and non-sterilized circles gave clear support for the growth of algae even in non-sterile environments. and therefore its applicability in water treatment plants would be economically acceptable. the results showed that the characteristics of the dairy wastewater play an important role in the removal and dissolved of biogases. a. r. ibrahim and b. a. abdulmajeed / iraqi journal of chemical and petroleum engineering 19,3 (2018) 1-9 8 nevertheless, this behavior may give sufficient time advantage to bacteria and the microalgae for the consumption of biogas resulting from the metabolic processes via mutually beneficial principle. the operational conditions of microalgae make bacteria able to grow and recover during the early hours of experimentation, even if sterilization was done. the results showed that ph control was an important step in improving the productivity of microalgae. the highest productivity was obtained at ph value 7, but its rise again will not take long. thus, the current study and through a series of experiments showed that ventilation may be the best way to control acidity. not only does it contain carbon dioxide, it also drives the process toward increasing the amount of carbon dioxide produced by bacteria that need air. acknowledgment the authors gratefully acknowledge to the department of biology in science college at the university of baghdad for the help and support. they also would like to thank the staff in the department of chemical engineering, college of engineering at baghdad university. nomenclatures parameter meaning unit doubling time day biomass dry weight mg. l -1 initial biomass dry weight mg. l -1 final biomass dry weight in exponential growth phase mg. l -1 specific growth rate day -1 kla volumetric mass transfer coefficient min -1 references [1] y. chisti, "biodiesel from microalgae," biotechnology advances, vol. 25, pp. 294-306, 2007. [2] a. radich, "biodiesel performance, costs, and use," energy information administration. u.s. department of energy., pp. 1-8, 2004. [3] v. singh, "effect of corn quality on bioethanol production," biocatalysis and agricultural biotechnology, vol. 1, pp. 353-355, 2012. [4] s. a. scott, m. p. davey, j. s. dennis, i. horst, c. j. howe, d. j. lea-smith, and a. g. smith, "biodiesel from algae: challenges and prospects," current opinion in biotechnology, vol. 21, pp. 277-286, 2010. [5] w. g. hettinga, h. m. junginger, s. c. dekker, m. hoogwijk, a. j. mcaloon, and k. b. hicks, "understanding the reductions in us corn ethanol production costs: an experience curve approach," energy policy, vol. 37, pp. 190-203, 2009. [6] n. liu, y. yang, f. li, f. ge, and y. kuang, "importance of controlling ph-depended dissolved inorganic carbon to prevent algal bloom outbreaks," bioresource technology, vol. 220, pp. 246-252, 2016. [7] l. rosgaard, a. j. de porcellinis, j. h. jacobsen, n. u. frigaard, and y. sakuragi, "bioengineering of carbon fixation, biofuels, and biochemicals in cyanobacteria and plants," journal of biotechnology, 2012. [8] r. a. i. abou-shanab, j. h. hwang, y. cho, b. min, and b. h. jeon, "characterization of microalgal species isolated from freshwater bodies as a potential source for biodiesel production," appl energy, vol. 88, 2011. [9] a. banerjee, r. sharma, y. chisti, and u. c. banerjee, "botryococcus braunii: a renewable source of hydrocarbons and other chemicals," critical reviews in biotechnology, vol. 22, pp. 245-279, 2002. [10] j. a. choi, j. h. hwang, b. a. dempsey, r. a. i. abou-shanab, b. min, h. song, d. s. lee, j. r. kim, y. cho, s. hong, and b. h. jeon, "enhancement of fermentative bioenergy (ethanol/hydrogen) production using ultrasonication of scenedesmus obliquus ysw15 cultivated in swine wastewater effluent," energy environ sci, vol. 4, 2011. [11] y. chisti, "biodiesel from microalgae beats bioethanol," trends in biotechnology, vol. 26, pp. 126131, 2008. [12] w. zhang and y.-j. tang, "biocatalysts and bioreactor design," biotechnology progress, vol. 24 pp. 1249-1261, 2008. [13] h. marschner, " mineral nutrition of higher plants," academic press, london, uk. [14] r. fayyad and a. dwaish, "examination the growth of blue-green alga, chroococcus turigidus in different traditional media formulations," journal of the college of basic education vol. 22, pp. 51-60, 2016. [15] h. wang, g. liu, r. ruan, and l. yuhuan, "biofuel from microalgae: current status, opportunity and challenge," in international conference on material and environmental engineering (icmaee 2014), 2014. [16] h.-j. choi, "dairy wastewater treatment using microalgae for potential biodiesel application," environ. eng. res., vol. 21, pp. 393-400, 2016. [17] s. hena, s. fatimah, and s. tabassum, "cultivation of algae consortium in a dairy farm wastewater for biodiesel production," water resources and industry, vol. 10, pp. 1-14, 2015. [18] i. woertz; a. feffer; t. lundquist; and y. nelson, "algae grown on dairy and municipal wastewater for simultaneous nutrient removal and lipid production for biofuel feedstock," journal of environmental engineering, vol. 135, 2009. [19] v. kothari, m. patadia, and n. trivedi, "microwave sterilized media supports better microbial growth than autoclaved media," research in biotechnology, vol. 2, pp. 63-72, 2011. [20] ding j., zhao f., cao y., xing l., liu w., mei s., and l. s, "cultivation of microalgae in dairy farm wastewater without sterilization," int j phytoremediation, vol. 17, pp. 222-227, 2015. https://www.sciencedirect.com/science/article/pii/s0734975007000262%20(let%c3%b6ltve:%202007 https://www.sciencedirect.com/science/article/pii/s0734975007000262%20(let%c3%b6ltve:%202007 http://large.stanford.edu/courses/2011/ph240/garcia1/docs/biodiesel.pdf http://large.stanford.edu/courses/2011/ph240/garcia1/docs/biodiesel.pdf http://large.stanford.edu/courses/2011/ph240/garcia1/docs/biodiesel.pdf https://www.sciencedirect.com/science/article/pii/s1878818112000989 https://www.sciencedirect.com/science/article/pii/s1878818112000989 https://www.sciencedirect.com/science/article/pii/s1878818112000989 https://www.sciencedirect.com/science/article/pii/s0958166910000443 https://www.sciencedirect.com/science/article/pii/s0958166910000443 https://www.sciencedirect.com/science/article/pii/s0958166910000443 https://www.sciencedirect.com/science/article/pii/s0958166910000443 https://www.sciencedirect.com/science/article/pii/s0301421508003996 https://www.sciencedirect.com/science/article/pii/s0301421508003996 https://www.sciencedirect.com/science/article/pii/s0301421508003996 https://www.sciencedirect.com/science/article/pii/s0301421508003996 https://www.sciencedirect.com/science/article/pii/s0301421508003996 https://www.sciencedirect.com/science/article/pii/s0960852416311877 https://www.sciencedirect.com/science/article/pii/s0960852416311877 https://www.sciencedirect.com/science/article/pii/s0960852416311877 https://www.sciencedirect.com/science/article/pii/s0960852416311877 https://www.sciencedirect.com/science/article/pii/s0168165612002787 https://www.sciencedirect.com/science/article/pii/s0168165612002787 https://www.sciencedirect.com/science/article/pii/s0168165612002787 https://www.sciencedirect.com/science/article/pii/s0168165612002787 https://www.sciencedirect.com/science/article/pii/s030626191100078x https://www.sciencedirect.com/science/article/pii/s030626191100078x https://www.sciencedirect.com/science/article/pii/s030626191100078x https://www.sciencedirect.com/science/article/pii/s030626191100078x https://www.sciencedirect.com/science/article/pii/s030626191100078x https://www.tandfonline.com/doi/abs/10.1080/07388550290789513 https://www.tandfonline.com/doi/abs/10.1080/07388550290789513 https://www.tandfonline.com/doi/abs/10.1080/07388550290789513 https://www.tandfonline.com/doi/abs/10.1080/07388550290789513 http://pubs.rsc.org/en/content/articlelanding/2011/ee/c1ee01068a/unauth#!divabstract http://pubs.rsc.org/en/content/articlelanding/2011/ee/c1ee01068a/unauth#!divabstract http://pubs.rsc.org/en/content/articlelanding/2011/ee/c1ee01068a/unauth#!divabstract http://pubs.rsc.org/en/content/articlelanding/2011/ee/c1ee01068a/unauth#!divabstract http://pubs.rsc.org/en/content/articlelanding/2011/ee/c1ee01068a/unauth#!divabstract http://pubs.rsc.org/en/content/articlelanding/2011/ee/c1ee01068a/unauth#!divabstract http://pubs.rsc.org/en/content/articlelanding/2011/ee/c1ee01068a/unauth#!divabstract https://www.sciencedirect.com/science/article/pii/s0167779908000218 https://www.sciencedirect.com/science/article/pii/s0167779908000218 https://www.sciencedirect.com/science/article/pii/s0167779908000218 https://onlinelibrary.wiley.com/doi/abs/10.1002/btpr.36 https://onlinelibrary.wiley.com/doi/abs/10.1002/btpr.36 https://onlinelibrary.wiley.com/doi/abs/10.1002/btpr.36 https://www.iasj.net/iasj?func=article&aid=115982 https://www.iasj.net/iasj?func=article&aid=115982 https://www.iasj.net/iasj?func=article&aid=115982 https://www.iasj.net/iasj?func=article&aid=115982 https://www.iasj.net/iasj?func=article&aid=115982 https://www.researchgate.net/profile/roger_ruan/publication/266651996_biofuel_from_microalgae_current_status_opportunity_and_challenge/links/54899d920cf214269f1aa37b.pdf https://www.researchgate.net/profile/roger_ruan/publication/266651996_biofuel_from_microalgae_current_status_opportunity_and_challenge/links/54899d920cf214269f1aa37b.pdf https://www.researchgate.net/profile/roger_ruan/publication/266651996_biofuel_from_microalgae_current_status_opportunity_and_challenge/links/54899d920cf214269f1aa37b.pdf https://www.researchgate.net/profile/roger_ruan/publication/266651996_biofuel_from_microalgae_current_status_opportunity_and_challenge/links/54899d920cf214269f1aa37b.pdf https://www.researchgate.net/profile/roger_ruan/publication/266651996_biofuel_from_microalgae_current_status_opportunity_and_challenge/links/54899d920cf214269f1aa37b.pdf https://www.e-sciencecentral.org/articles/sc000020191 https://www.e-sciencecentral.org/articles/sc000020191 https://www.e-sciencecentral.org/articles/sc000020191 https://www.sciencedirect.com/science/article/pii/s2212371715000219 https://www.sciencedirect.com/science/article/pii/s2212371715000219 https://www.sciencedirect.com/science/article/pii/s2212371715000219 https://www.sciencedirect.com/science/article/pii/s2212371715000219 https://ascelibrary.org/doi/abs/10.1061/(asce)ee.1943-7870.0000129 https://ascelibrary.org/doi/abs/10.1061/(asce)ee.1943-7870.0000129 https://ascelibrary.org/doi/abs/10.1061/(asce)ee.1943-7870.0000129 https://ascelibrary.org/doi/abs/10.1061/(asce)ee.1943-7870.0000129 https://ascelibrary.org/doi/abs/10.1061/(asce)ee.1943-7870.0000129 http://updatepublishing.com/journal/index.php/rib/article/view/2372 http://updatepublishing.com/journal/index.php/rib/article/view/2372 http://updatepublishing.com/journal/index.php/rib/article/view/2372 http://updatepublishing.com/journal/index.php/rib/article/view/2372 https://www.tandfonline.com/doi/abs/10.1080/15226514.2013.876970 https://www.tandfonline.com/doi/abs/10.1080/15226514.2013.876970 https://www.tandfonline.com/doi/abs/10.1080/15226514.2013.876970 https://www.tandfonline.com/doi/abs/10.1080/15226514.2013.876970 a. r. ibrahim and b. a. abdulmajeed / iraqi journal of chemical and petroleum engineering 19,3 (2018) 1-9 9 [21] w. bank, "pollution prevention and abatement handbook: dairy industry," ed washington, d.c: the international bank for reconstruction and development, 1999. [22] z. tomáš, s. m. a., b. diana, l. petra, and č. jan, "characterization of a model cyanobacterium synechocystis sp. pcc 6803 autotrophic growth in a flat-panel photobioreactor," engineering in life sciences, vol. 15, pp. 122-132, 2015. [23] m. k. h. al-mashhadani and e. m. khudhair, "experimental study for commercial fertilizer npk (20:20:20+te n:p: k) in microalgae cultivation at different aeration periods," iraqi journal of chemical and petroleum engineering, vol. 18, pp. 99 110, 2017. [24] p. pachiappan, b. b. prasath, s. perumal, s. ananth, a. shenbaga devi, s. d. kumar, and s. jeyanthi, "isolation and culture of microalgae," in advances in marine and brackishwater aquaculture, s. perumal, t. a.r, and p. pachiappan, eds., ed new delhi: springer india, 2015, pp. 1-15. [25] m. k. h. al-mashhadani and e. m. khudhair, cultivation of chlorella vulgaris using airlift photobioreactor sparged with 5%co2-air as a biofixing process”, journal of engineering, vol. 23, pp. 22-41, 2017. [26] c. edwards., b. i. duerden, and d. n. w. read, "the effects o f ph on colonic bacteria grown in continuous culture," journal of medical microbiology, vol. 19, pp. 169-80, 1985. [27] a. tikariha and o. sahu, "study of characteristics and treatments of dairy industry waste water," journal of applied & environmental microbiology, vol. 2, pp. 16-22, 2014. [28] s. p. singh and p. singh, "effect of temperature and light on the growth of algae species: a review," renewable and sustainable energy reviews, vol. 50, pp. 431-444, 2015/10/01/ 2015. [29] m. k. h. al-mashhadani, s. j. wilkinson, and w. b. zimmerman, "carbon dioxide rich microbubble acceleration of biogas production in anaerobic digestion," chemical engineering science, vol. 156, pp. 24-35, 2016. [30] m. szuhaj, n. ács, r. tengölics, a. bodor, g. rákhely, k. l. kovács, and z. bagi, "conversion of h2 and co2 to ch4 and acetate in fed-batch biogas reactors by mixed biogas community: a novel route for the power-to-gas concept," biotechnology for biofuels, vol. 9, p. 102, may 10 2016. [31] e. metcalf wastewater engineering treatment and reuse: mcgraw hill, 2003. [32] a. m. m. khalil i. zeinab and k. a. i. el-sayed salwa "effect of ph on growth and biochemical responses of dunaliella bardawil and chlorella ellipsoidea," world j microbiol biotechnol, vol. 26, pp. 1225–1231, 2010. [33] a. çelekli and g. dönmez, "effect of ph, light intensity, salt and nitrogen concentrations on growth and β-carotene accumulation by a new isolate of dunaliella sp," world journal of microbiology and biotechnology, vol. 22, p. 183, 2005. [34] m. khan;, r. karmakar;, b. das;, f. diba;, and m. h. razu;, "heterotrophic growth of micro-algae," recent advances in microalgal biotechnology, pp. 118, 2016. مستخدما مفاعل التعايش البيولوجي لنظام الطحالب الدقيقة والبكتريا في مخلفات االلبان حيوي ضوئي الخالصة رْبوىذ اىذساسخ اىؾبىٍخ ّظبً اىزهىٌخ فً صساعخ اىطؾبىت اىذقٍقخ ثبسزخذاً ٍخيفبد االىجبُ مىسظ صسعً. هزا اىجؾش هذف اىى دساسخ ربصٍش اىزهىٌخ فً ٍفبعو اىفقبعخ اىعَىدي اىؾٍىي عيى اىزآصس اىؾٍىي ثٍِ اىطؾبىت واىجنزشٌب ارا رٌ ؽيخ اىزعقٌٍ ىٍسذ اىخطىح اىَهٍَْخ فً ّغبػ صساعخ اىطؾبىت فً ٍٍبٓ غٍْخ رىاعذهَب فً ّفس اىَنبُ. اىْزبئظ رجٍِ ثبُ ٍش فً االوسبط اىضسعٍخ اىَعقَخ وغٍش اىَعقَخ، chlorella ثبىَخيفبد اىعضىٌخ. هْبك رقبسة واضؼ ثٍِ ٍعذه َّى واىزً رعطً واقعٍخ إرا رٌ رطجٍق االقزشاػ صْبعٍب. ٍِ خاله اىَعيىٍبد اىزً رٌ اىؾصىه عيٍهب ، ٌَنِ ىيجنزٍشٌب اىهىائٍخ زىل فً االوسبط غٍش اىَعقَخ ، اىخبىٍخ ٍِ اىطؾبىت ، أُ رسزهيل مو األمسغٍِ اىَزاة فً غضىُ فزشح صٍٍْخ قصٍشح. ى ، فإُ عبٍو اىزهىٌخ ٍهٌ فً هزٓ اىؾبىخ. ٍع رىل ، رظهش اىزغبسة أُ اىزعبٌص ثٍِ اىجنزٍشٌب واىطؾبىت اىذقٍقخ ٌَنِ أُ ٌؾذس ؽزى ىى ىٌ ٌنِ هْبك ّظبً رهىٌخ. وثبىزبىً ، فإُ اىطؾبىت اىَغهشٌخ فً اىَخيفبد اىَبئٍخ ىألىجبُ قبدسح عيى اىؾفبظ صاد اىْبرغخ ثسجت عَيٍبد اىزَضٍو اىغزائً فً اىجنزٍشٌب أو اىطؾبىت اىذقٍقخ رجقى فً عيى ثٍئخ اىضساعخ ٍْبسجخ. اىغب . وثبىزبىً ، فإُ هزا سٍعطً وقزب وىٍس ٍِ اىسهىىخ اصىزهب, خبصخ ارا مبّذ فزشح ضخ اىهىاء ٍزقطعخاىَؾيىه ىفزشح ٍعٍْخ دقٍقخ وصالس 51فإُ اىْزبئظ رظهش أُ ّظبً اّزعبش ىَذح مبفٍب ىنال اىنبئْبد اىؾٍخ اىذقٍقخ ىزسزهيل ريل اىغبصاد. وٍع رىل ، ٪. وىزىل ، فإُ صساعخ اىطؾبىت اىَغهشٌخ ثبإلضبفخ إىى هذفهب 06ٍشاد فً اىٍىً ٌؾسِ إّزبط اىنزيخ اىؾٍىٌخ ثْسجخ جخ اىَْشىد ٌَنِ أُ ريعت دوساً هبٍبً فً وؽذاد ٍعبىغخ ٍٍبٓ اىصشف اىصؾً ٍِ خاله اىؾفبظ عيى اىجٍئخ اىَْبس ىيجنزٍشٌب اىهىائٍخ ؽزى فً ؽبىخ عذً وعىد ّظبً رهىٌخ. https://onlinelibrary.wiley.com/doi/abs/10.1002/elsc.201300165 https://onlinelibrary.wiley.com/doi/abs/10.1002/elsc.201300165 https://onlinelibrary.wiley.com/doi/abs/10.1002/elsc.201300165 https://onlinelibrary.wiley.com/doi/abs/10.1002/elsc.201300165 https://onlinelibrary.wiley.com/doi/abs/10.1002/elsc.201300165 https://www.iasj.net/iasj?func=article&aid=123029 https://www.iasj.net/iasj?func=article&aid=123029 https://www.iasj.net/iasj?func=article&aid=123029 https://www.iasj.net/iasj?func=article&aid=123029 https://www.iasj.net/iasj?func=article&aid=123029 https://www.iasj.net/iasj?func=article&aid=123029 https://link.springer.com/chapter/10.1007/978-81-322-2271-2_1 https://link.springer.com/chapter/10.1007/978-81-322-2271-2_1 https://link.springer.com/chapter/10.1007/978-81-322-2271-2_1 https://link.springer.com/chapter/10.1007/978-81-322-2271-2_1 https://link.springer.com/chapter/10.1007/978-81-322-2271-2_1 https://link.springer.com/chapter/10.1007/978-81-322-2271-2_1 https://jcoeng.edu.iq/index.php/main/article/view/49 https://jcoeng.edu.iq/index.php/main/article/view/49 https://jcoeng.edu.iq/index.php/main/article/view/49 https://jcoeng.edu.iq/index.php/main/article/view/49 https://jcoeng.edu.iq/index.php/main/article/view/49 http://jmm.microbiologyresearch.org/content/journal/jmm/10.1099/00222615-19-2-169 http://jmm.microbiologyresearch.org/content/journal/jmm/10.1099/00222615-19-2-169 http://jmm.microbiologyresearch.org/content/journal/jmm/10.1099/00222615-19-2-169 http://jmm.microbiologyresearch.org/content/journal/jmm/10.1099/00222615-19-2-169 http://pubs.sciepub.com/jaem/2/1/4/ http://pubs.sciepub.com/jaem/2/1/4/ http://pubs.sciepub.com/jaem/2/1/4/ http://pubs.sciepub.com/jaem/2/1/4/ https://www.sciencedirect.com/science/article/pii/s1364032115004839 https://www.sciencedirect.com/science/article/pii/s1364032115004839 https://www.sciencedirect.com/science/article/pii/s1364032115004839 https://www.sciencedirect.com/science/article/pii/s1364032115004839 https://www.sciencedirect.com/science/article/pii/s0009250916304900 https://www.sciencedirect.com/science/article/pii/s0009250916304900 https://www.sciencedirect.com/science/article/pii/s0009250916304900 https://www.sciencedirect.com/science/article/pii/s0009250916304900 https://www.sciencedirect.com/science/article/pii/s0009250916304900 https://biotechnologyforbiofuels.biomedcentral.com/articles/10.1186/s13068-016-0515-0 https://biotechnologyforbiofuels.biomedcentral.com/articles/10.1186/s13068-016-0515-0 https://biotechnologyforbiofuels.biomedcentral.com/articles/10.1186/s13068-016-0515-0 https://biotechnologyforbiofuels.biomedcentral.com/articles/10.1186/s13068-016-0515-0 https://biotechnologyforbiofuels.biomedcentral.com/articles/10.1186/s13068-016-0515-0 https://biotechnologyforbiofuels.biomedcentral.com/articles/10.1186/s13068-016-0515-0 https://link.springer.com/article/10.1007/s11274-009-0292-z https://link.springer.com/article/10.1007/s11274-009-0292-z https://link.springer.com/article/10.1007/s11274-009-0292-z https://link.springer.com/article/10.1007/s11274-009-0292-z https://link.springer.com/article/10.1007/s11274-009-0292-z https://link.springer.com/article/10.1007/s11274-005-9017-0 https://link.springer.com/article/10.1007/s11274-005-9017-0 https://link.springer.com/article/10.1007/s11274-005-9017-0 https://link.springer.com/article/10.1007/s11274-005-9017-0 https://link.springer.com/article/10.1007/s11274-005-9017-0 ijcpe vol.9 no. 2 (june 2008) iraqi journal of chemical and petroleum engineering vol.9 no.2 (june 2008) 57-67 issn: 1997-4884 effect of operating cconditions on hydrodesulfurization of vacuum gas oil abdul halim a. karim mohammed * abdul mun’m a.karim ** and haider a.areff. * chemical engineering department, college of engineering, university of baghdad ** chemical engineering department, college of engineering, university of tikrit abstract this study was conducted according to contract with the north refineries company-baiji and deals with the hydrodesulphurization of vacuum gas oil of kirkuk crude oil, boiling range 611-833 k. a trickle bed reactor packed with a commercial cobalt-molybdenum on alumina catalyst was used. the operating conditions were: temperature range 583-643 k, liquid hourly space velocity range 1.50-3.75 1/h, hydrogen to oil ratio about 250 l/l and pressure kept constant at 3.5mpa. the results showed that the aromatic content decreased and sulfur removal increased with increasing temperature and decreasing space velocity. the properties (viscosity, density, flash point and carbon residue) of the products decrease with temperature increasing, but the aniline point increased. introduction hydrotreating process plays an important role in the refinery. it is a catalytic conversion for removal of organic sulfur, nitrogen, oxygen compounds and metals from petroleum fractions and residue at high hydrogen pressures and temperatures accompanied by hydrogenation of unsaturated and cracking of feedstock’s to lower molecular weight hydrocarbons. indeed, hydrotreating capacity has been growing steadily (at about 6% per year since 1976) and represents today nearly 50% of the total refining capacity [1]. the increasing application of hydrotreating can be ascribed to: i-the ever decreasing availability of light,sweet crudes and thus the increasing fraction of heavy ,high sulfur crudes that must be processed.ii-the trend to increase upgrading of feedstock’s for improvement of downstream processing such as catalytic reforming and catalytic cracking [2]. the hydrodesulphurization (hds) of petroleum fractions has long been an integral part of refining operation. hds is practiced in every modern refinery (3) . the technology of the hds process is well established, and petroleum stocks of every conceivable molecular weight range can be treated to remove sulfur. thus, it is not surprising that an extensive knowledge of hds has been acquired along with the development of the process over the last few decades. however, most of the available information pertaining to the hds process has been obtained with the lighter and more easily desulfurized petroleum fractions, but it is, to some degree to the hds of the heavier feedstocks such as the heavy oils, vacuum gas oil and residua. on the other hand, the processing of the heavy oils and residua present several problems that are not found with distillates processing and which require process modification to meet the special requirements that are necessary for heavy feedstock desulfurization [3]. hydrodesulphurization of heavy oils to meet rapidly increasing low sulfur fuel market is one of the major technical and economic challenges facing the refining industry during this decade. one route to low sulfur oil production is vacuum gas oil (vgo) desulfurization. atmospheric distillation tower residuum is first fractionated in vacuum distillation tower to vacuum gas oil and residuum. the sulfur content of the vacuum gas oil then significantly reduced by the means of catalytic hds. this process has the advantage of being relatively inexpensive. feed stock to this process may include university of baghdad college of engineering iraqi journal of chemical and petroleum engineering effect of operating condition on hydrodesulfurization of vacuum gas oil 58 ijcpe vol.9 no. 2 (june 2008) virgin and visbreaker vacuum gas oil, thermal and catalytic cycle oils and coker gas oil[4,5]. several classes of reactions occur simultaneously in hds process which include hydrodenitrogenation (hdn), hydrodeoxygenation(hdo), hyrdocracking and hydrogenation [6]. the present work deals with the effect of temperature and lhsv on the hds of vacuum gas oil using trickle bed reactor, experimental work the feedstock used in the present work is a vgo of kirkuk crude oil with boiling range 611-833 k. it was prepared by blending the fractions: light vgo (611-650 k),medium vgo (650-690 k), heavy vgo (690-727 k) and very heavy vgo ( 727-833 k) with volume percentages 13.67, 21.67, 27.00 and 37,66, respectively. the properties of the vgo used in this investigation are given in table 1. the sulfur content of the feedstock and the hydrotreated products was determined according to bomb method (astm: d 129-64). the group’s composition of vgo and the hydrotreated products were determined by liquid solid chromatography using silica gel as the adsorbent. the chromatographic column has about 25 mm in. diameter, packed to a height of 500 mm with silica gel and made of glass. about 2 g of sample was introduced into the column each time. the column is shown in figure 1. the saturated fraction eluted from column by 150 ml of n-hexane, then the aromatic fraction eluted by 200 ml of benzene. finally, the polar aromatic fraction eluted with 150 ml of methanol-benzene mixture (20/80 by volume).table 2 shows the sulfur content, aromatic and saturated fractions distribution in feedstock fraction. the catalyst used was a commercial cobaltmolybdenum on alumina (co-mo-alumina) type and its properties are shown in table 3. 120 ml of the fresh catalyst was first dried for two hours and then placed inside the hds trickle bed reactor. the catalyst was surrounded by two beds of inert material at top and bottom of the reactor of 135 mm height each. the catalyst was presulfided to promote its activity by passing a solution of 0.6% of carbon disulfide in commercial gas oil over it. this activation process was carried out in two stages. the first stage was at pressure of 2.1 mpa, temperature of 477 k and liquid hourly space velocity of 4 1/h for 4 hours with no hydrogen flow. the second stage was at pressure of 2.1 mpa, temperature of 573 k and lhsv of 1 1/h for 16 hours and hydrogen to oil ratio of 200 l/l. the hds runs were performed in a laboratory continuous high pressure unit employing an up-flow cocurrent trickle bed reactor. figure 2 shows the flow diagram of the hds unit. the reactor was made of 316 stainless steel, having 20 mm in. diameter and 650 mm height. it was jacketed with five separately heatcontrolled block shells in order to keep a certain isothermal operation. the reactor effluent was cooled in a condenser-cooler and the liquid products were separated from unreacted hydrogen gas, hydrogen sulfide and the hydrocarbon gases in a high and low pressure separators. the gases were vented to the exterior through gas flow meter. a high pressure dosing pump was used to introduce the feedstock to the reactor. a calibrated micrometer was fitted to the pump to estimate the feedstock flow rate. the hydrogen gas was fed to the reactor from a hydrogen cylinder through a heated high pressure line. the hydrogen gas flow rate was estimated by electrical gas inlet flow sensor using standard calibrations with the electrical pulses. the hds experiments of the vgo were carried out with: temperature range of 583-643 k, lhsv ranging from 1.5 to 3.75 1/h, hydrogen pressure was kept constant at 3.5 mpa and hydrogen to feed ratio was approximately 250 l/l. when the steady-state operation was established, the products were collected. the hydrodesulfurized product was fractionated by a laboratory distillation unit. the unit consisted mainly of round bottom flask, distillation column, still head distillate recievers, reflux condenser and vacuum system. the flow diagram of the unit is shown in fig. 3. the distillation unit was operated at atmospheric pressure up to a distillation temperature of 611 k. the distillation unit system was, then, connected to a vacuum pump through a vapor trap to continue the distillation at a vacuum pressure as low as 0.5 mm hg. a magnetic valve connected to the reflux timer was used to obtain the desired reflux ratio. the reflux ratio was 3:1 for distillation temperature up to 611 k and 1:1 for the remainder fractions. the specific gravity, flash point, kinematic viscosity and carbon residue of the feedstock and the products were measured by using ip 120/64, ip 15/57, ip 319/75 and ip 3/66, respectively. table 1 properties of feedstock specification value sp.gr.at 60/60 f api viscosity at 323 k, cs 373 k, cs pour point, k flash point, k anline point, k ccr, wt% sulfur content, wt% 0.911 23.858 11.563 2.784 302 465 325 0.58 2.5 abdul halim a. karim mohammed ,abdul mun’m a.karim and haider a.areff. 59 ijcpe vol.9 no. 2 (june 2008) table 2 sulfur, aromatics and saturated fraction distribution in feed stock fractions sulfur, wt% aromatics, wt% saturated, wt% lvgo (611-560 k) mvgo (650-690 k) hvgo (690-727 k) very hvgo (727-833 k) 2.38 2.4 2.5 2.6 16 24 34 50 83 76 66 5 table 3 the catalyst properties chemical properties value wt% moo3 coo sio2 na2o fe so2 al2o3 15.0 3.0 1.1 0.07 0.04 2.0 balance physical properties value form surface area, m 2 /g, pore volume, cm 3 /g bulk density, g/cm 3 mean particle diameter, mm mean particle length, mm extrudate 180 0.5 0.67 1.8 4 effect of operating condition on hydrodesulfurization of vacuum gas oil 60 ijcpe vol.9 no. 2 (june 2008) fig. 2 floe diagram of laboratory hydrodesulphurization unit results and discussion the hds of vgo in a fixed catalyst bed reactor is a complex process and many variables affect the extent of sulfur removel .the main variables are temperature , pressure, lhsv and hydrogen to oil volumetric ratio. through the present study , the hydrogen pressure and the hydrogen to oil ratio were kept constant. at constant lhsv , the sulfur content of hydrodesulfurized products decreased (figure 4) as the reaction temperature increased ,hence , the sulfur removal increased (figure 5) . whereas at constant temperature, the sulfur content increased as the lhsv increased as shown in figure 6 . the results are in agreement with other studies for the hds (7-10 ). the icreasing sulfur removal at high reaction temperature may be attributed to several reasons. firstly, the unreactive sulfur compounds which most properly belong to thiophene derivatives become activated enough to react with hydrogen and secondly, the aromatic compounds are decomposed to smaller molecules which can more easily diffuse into the catalyst micro and mesopores and reach the inner active sites where the desulfurization reaction mainly occur(9).thus ,the upper temperature value is limited by the undesirable side reactions such as hydrocracking and thermal cracking reactions which are expected to occur at high temperature. the contact time between the reacting fluid and catalyst decreased when increasing the lhsv and this led to the sulfur removel decrease with icreasing lhsv. the distribution of sulfur content in the hydrodesulfurized fractions, lvgo, mvgo, hvgo and very heavy vgo at 643 k is shown in fig. 7.this figure shows that the sulfur content of any fraction decreased with decreasing lhsv. figures 8 and 9 show that the decreasing percentage of aromatic compounds and the increasing percentage of saturated compounds in the hydrodesulfurized proudct both increase with icreasing reaction temperature and decreasing of lhsv.this is due to the increase of the rate of hydrogenation of aromatics and the increase of the contact time as mentioned by girgis(6). the effect of hydrotreating temperature and lhsv on aniline point of the hydrotreated products are shown in figures 10 and 11. the aniline point increases with temperature increase and lhsv decrease due to the increase of the rate of hydrogenation reaction. the viscosity, flash point, density and carbon residue decrease with increasing temperature and reaction time as shown in figures 12-19. the decrease in these properties is due to the increase in the rate of hydrogenation and hydrocracking reactions. abdul halim a. karim mohammed ,abdul mun’m a.karim and haider a.areff. 61 ijcpe vol.9 no. 2 (june 2008) fig. 3: laboratory distillation unit fig. 4 effect of lhsv on the sulfur content of the hydrotreated product. fig. 5: effect of lhsv on the sulfur removal of the hydrotreated product. effect of operating condition on hydrodesulfurization of vacuum gas oil 62 ijcpe vol.9 no. 2 (june 2008) fig. 6: effect of temperature on the sulfur content of the hydrotreated product. fig. 7: distribution of sulfur in hydrotreated friction at 643° k abdul halim a. karim mohammed ,abdul mun’m a.karim and haider a.areff. 63 ijcpe vol.9 no. 2 (june 2008) fig. 8: effect of lhsv on the aromatic and saturated content of hydrotreated product effect of operating condition on hydrodesulfurization of vacuum gas oil 64 ijcpe vol.9 no. 2 (june 2008) fig. 9: effect of temperature on the aromatic and saturated content of hydrotreated product. fig.10: effect of hydrotreating on aniline point of the hydrotreated product. fig.11:fect of lhsv on aniline point hydrotreated product abdul halim a. karim mohammed ,abdul mun’m a.karim and haider a.areff. 65 ijcpe vol.9 no. 2 (june 2008) fig.12: effect of hydrotreating on viscosity of the hydrotreated product. fig.13: effect of lhsv on the viscosity of hydrotreated product fig.14: effect of hydrotreating on the flash point of the hydrotreated product fig.15: effect of lhsv on the flash point of the hydrotreated product effect of operating condition on hydrodesulfurization of vacuum gas oil 66 ijcpe vol.9 no. 2 (june 2008) fig.16: effect of hydrotreating temperature on the density of the hydrotreated product fig.17: effect of lhsv on the density of the hydrotreated product fig.18: effect of hydrotreating on the carbon residue of the hydrotreated product fig.16: effect of lhsv on the carbon residue of the hydrotreating product. abdul halim a. karim mohammed ,abdul mun’m a.karim and haider a.areff. 67 ijcpe vol.9 no. 2 (june 2008) conclusions 1. sulfur removal from vacuum gas oil produced in baiji refinery is highly dependent on reaction temperature and lhsv variation within the range of studied operation. 2. the aromatic compounds of the hydrodesulfurized products decrease with icreasing the reaction temperature and decreasing of lhsv, while the saturated compounds increase with temperature increasing and lhsv decreasing. 3. the viscosity of hydrodesulfurized products decrease with reaction temperature and space time ( 1/lhsv) increasing ,while, the aniline point increases with temperature increasing and lhsv decreasing reference 1. mc culloch, d, c. , catalytic hydrotreating in petroleum refining, applied industrial catalysis, ed.b.e. leach, akademic press, vol. 1, p 69, 1983. 2. bartholomew, c. h., catalyst deactivation in hydrotreating of residue, applied industrial catalysis, ed. b.e. leach, academic press, vol. 1, p 64. 3. speight, j. g. , the desulfurization of heavy oils residua, 1981. 4. hobson, g.d., modern petroleum technology, 5 th ed.,part 1, 1984. 5. antos, g. j and wang, l., successful commercial hydrocracking catalysts, tools and methodologies, 2000. 6. grirais, m, j and gates, b. c. , ind. eng. chem. res., vol. 30, pp 2021-2058, 1991. 7. vicic, d. a and jones, w. d., hydrodesulfurization of thiophene and benzothiophene to butane and ethyl benzene by a homogeneous iridium complex, organomet.,voi. 16, pp 1912-1919, 1997. 8. antonio iannibllo, sergio marengo, geriendo burgio, glancario baldi and vito specchia, ind. eng. chem. process des. dev., vol. 24, pp 531537, 1985. 9. mann, r. s, sambi, l. s and khulba, c. k., ind. eng. chem. res, vol, 27, pp 1788-1792, 1988. 10. froment, g. f., depauw, g, a and vanrysselberghe, v., ind. eng. chem. res., vol. 33, pp 2975-2988, 1994. iraqi journal of chemical and petroleum engineering vol.15 no.3 (september 2014) 9-18 issn: 1997-4884 corrosion inhibition of mild steel by curcuma extract in petroleum refinery wastewater aprael s. yaro a and kabas f. talib b chemical engineering department-college of engineeringuniversity of baghdad, iraq a, e-mail: apraely@yahoo.com b, e-mail: barby_eng_1990@yahoo.com abstract the inhibitor property of curcuma longa l. extract in different concentrations of simulated refinery wastewater (0.05% 2% wt) and at various temperatures (30, 35 and 40 ˚c) was investigated using weight loss method. the results showed that the presence of about 1.2 % (v/v) of curcuma extract gave about 84% inhibition indicating its effectiveness on mild steel corrosion in simulated refinery wastewater, besides the adsorption process on the mild steal surface obeyed the langmuir adsorption isotherm. keywords: corrosion, oil industry, steel, curcuma extract introduction mild steel is one of the most widely used engineering materials, despite its relatively limited corrosion resistance. corrosion is one of the main concerns in the durability of metallic materials and their structures. many efforts have been made to develop a corrosion inhibition process to prolong the life of existing structures and minimize corrosion damages [1]. water pollution not only is harmful to mankind but also is harmful to metallic equipment such as pipelines, storage tanks, pumps, heat exchangers, etc., that are used in handling wastewater [2]. in addition to causing the eventual failure of the metallic equipment, corrosion by industrial wastewater leads to water pollution by the dissolved metal ions such as cu ++ , cd ++ and pb ++ , which themselves also may be toxic [3]. the type and rate of corrosion depends on the nature and concentration of pollutants present in the wastewater. steel suffers severe corrosion attack in wastewater containing electrolytes. the rate of corrosion depends, amongst other factors, upon the concentration of oxygen and the motion of water. steel with residual stresses undergoes stress corrosion cracking in wastewater containing nitrates, for example in the case of agricultural runoff waters containing nitrate fertilizer. mild steel sustains severe damage in wastewater solutions containing chlorides, where pitting corrosion and stress corrosion cracking take place [4, 5]. crude oil usually contains some water-dissolved salts such as cacl2 and mgcl2. before processing crude oil in the distillation tower, the water iraqi journal of chemical and petroleum engineering university of baghdad college of engineering mailto:eng_1990@yahoo.com corrosion inhibition of mild steel by curcuma extract in petroleum refinery wastewater 10 ijcpe vol.15 no.3 (september 2014) -available online at: www.iasj.net should be removed first by a process known as dehydration and desalting. early water removal from crude oil minimizes corrosion of process equipment such as pumps, heat exchangers, distillation towers and condensers. on the other hand, the equipment used for handling water that has been separated from the oil can suffer from severe corrosion, depending upon the salt content of water [6]. a wide range of materials known as inhibitors are used to control the corrosion. the recent trend is towards developing environment friendly inhibitors. most of the natural products are non-toxic, bio-degradable and readily available in plenty. various parts of plants-seeds, fruits, leaves, flowers, etc. have been used as corrosion inhibitors [7]. the present work is another trial to find the effect of aqueous extract of the plant material known as curcuma powder as a green inhibitor for mild steel in petroleum refinery wastewater produced from desalting process of crude oil. experimental work synthetic magnesium chloride solution, simulated refinery wastewater, produced from desalting process of crude oil [8] were used, under static conditions in the presence and absence of curcuma extract as a corrosion inhibitor of concentrations of 1, 5 and 9 ml/250ml of mgcl2 solution which was used as corrosive media at 30 ˚c. the corrosion rate of mild steel was found by weight loss method. materials a mild steel sheet (supplied by engineering lab. and inspection department, ministry of science and technology) was used as working electrode with the following chemical composition: table 1: the chemical composition of mild steel coupon (wt %) wt% component 0.069 carbon 0.441 manganese 0.026 nickel 0.005 sulfur 0.009 silicon remainder fe test specimens of rectangular shape with 1.5 cm (width), 3.5 cm (length) and 0.1 cm thickness were used in weight loss method. solutions  simulated petroleum refinery wastewater: the wastewater was prepared by dissolving appropriate amount of mgcl2 in one liter of distilled water.  aqueous extract of curcumin dye: 10 g of rhizome (curcuma longa l.) powder was weighed and boiled with double distilled water. the yellow dye curcumin was filtered to remove suspending impurities and made up to100 ml. the curcumin dye (cd) was used as corrosion inhibitor in the present study [9]. weight loss method a. specimen preparation: coupon specimens were annealed in a vacuum at 600 ˚c for 1.0 h and the furnace was cooled to room temperature. this was carried out in order to remove mechanical stresses. an annealed specimens were abraded in sequence under running tap water using emery paper of grade 120, 220, 320,400 and 600, respectively ,washed with running tap water followed by distilled water ,dried on clean tissue, immersed in benzene for 5 seconds and dried with clean tissue ,immersed in acetone for 5 seconds and dried with clean tissue and then aprael s. yaro and kabas f. talib -available online at: www.iasj.net ijcpe vol.15 no.3 (september 2014) 11 kept in desiccators over silica gel until use. b. procedure: 1. the dimensions of each specimen were measured with vernier to the 2 nd decimal of millimeter and weighed accurately to the 4 th decimal of gram before using. 2. specimens were completely immersed in 250 ml of corroding solution contained in (500 ml) beakers. they were exposed for period of 24 h, at required temperature, desired concentration of inhibitor and required concentration of solutions. after each test, the specimen was washed with running tap water, scrubbed with a brush to remove corrosion products, washed with tap water followed by distilled water and dried on a clean tissue, immersed in benzene, dried, immersed in acetone, dried and left in a desiccators over silica gel for one hour before weighting. results and discussion a total of 18 runs for weight loss measurements were made expressing the corrosion rate of mild steel in simulated petroleum refinery wastewater with an increasing concentration from 0.05 to 2% wt. the parameters studied were concentration of mgcl2 and concentration of corrosion inhibitor (aqueous extract of curcuma). corrosion rate calculations from weight loss data were performed according to eq. 1: …(1) the results showed in tables 2 and 3 express the corrosion rate and inhibition efficiency of mild steel in simulated petroleum refinery wastewater with different concentrations of aqueous extract of curcuma as green inhibitor. table 2: corrosion rate (gmd) of mild steel in simulated petroleum refinery wastewater with different concentration of extracted curcuma at 30 ˚c curcuma (ml/250 ml soln.) mgcl2 wt% 0.05 1.025 2 0 4.9263 4.4162 4.0235 1 2.8959 2.7220 3.4620 3 0.7761 2.0883 3.1772 5 0.9939 1.5426 2.6560 7 1.2715 1.4540 2.0344 9 1.7013 1.6263 2.2035 table 3: inhibition efficiency (ie %) of different concentrations of extracted curcuma in simulated petroleum refinery wastewater at 30 ˚c curcuma (ml/250ml soln.) mgcl2 wt% 0.05 1.025 2 1 41.21 38.36 13.96 3 84.25 52.71 21.03 5 79.83 65.07 33.99 7 74.19 67.08 49.44 9 65.47 63.17 45.24 fig. 1: corrosion rate and inhibition efficiency of mild steel as function of inhibitor concentrations (extracted curcuma concentration) in simulated petroleum refinery wastewater at 30 ˚c the results showed in tables 2 and 3 and figure 1 indicate that the addition of aqueous extract of curcuma as corrosion inhibitor to different concentrations of simulated petroleum corrosion inhibition of mild steel by curcuma extract in petroleum refinery wastewater 12 ijcpe vol.15 no.3 (september 2014) -available online at: www.iasj.net refinery wastewater decreased the corrosion rate of mild steel. (ie., the maximum corrosion inhibition achieved was 84.25% and the minimum one was 13.96%). regression analysis was utilized by using statistica program version 10.1 to generate a model to describe the response of the mild steel with correlation coefficient of r 2 =0.91 through implementing the 2 nd order polynomial model. cr (gmd) = 4.005950 -0.164999x1 0.914977x2+0.190011x1 2 +0.067442x 2 2 +0.053740x1x2 …(2) where x₁ and x₂ are mgcl2 concentration, and inhibitor concentration, respectively. equation 2 is applied to estimate the corrosion rate of the mild steel in simulated petroleum refinery wastewater. the quantitative description of the physical condition effect on corrosion rate of mild steel in simulated petroleum refinery wastewater performed. an empirical modeling technique called response surface methodology is used to evaluate the relationship between the controllable experimental variables and observed results [10]. figures 2 and 3 show the effect of studied variables on the corrosion rate and inhibition of mild steel in refinery wastewater, respectively. figure 2 corroborates that the minimization of corrosion rate of mild steel is possible in refinery wastewater containing low concentration of mgcl2% and high concentration of extracted curcuma. the darker the red color means higher corrosion rate, while the darker the green color means the lowest one. figure 3 shows the response surface for the inhibition of mild steel due to the effect of mgcl2% concentration and curcuma extract concentration. the darker the red color means the higher the inhibition efficiency, while the darkest the green one means the lower the inhibition efficiency. > 4 < 4 < 3 < 2 < 1 0 1 2 3 4 5 6 7 8 9 ex tra cte d c urc um a ( ml /25 0m l s oln .) 0.0 0. 2 0.4 0. 6 0. 8 1.0 1. 2 1. 4 1.6 1 . 8 2 . 0 m gcl2 wt% 1 2 3 4 5 c r (g m d ) fig. 2: corrosion rate response surface for mgcl2 concentration and extracted curcuma aprael s. yaro and kabas f. talib -available online at: www.iasj.net ijcpe vol.15 no.3 (september 2014) 13 > 80 < 64 < 44 < 24 < 4 0 1 2 3 4 5 6 7 8 9 ex tra cte d c urc um a ( ml /25 0m l s oln .) 0.0 0.2 0. 4 0. 6 0.8 1. 0 1 . 2 1 .4 1 . 6 1 .8 2 . 0 m gcl2 wt% 20 40 60 80 100 in h ib itio n e ffe ic ie n c y fig. 3: inhibition efficiency response surface for mgcl2 concentration and extracted curcuma adsorption studies and inhibition mechanism the primary step in the action of inhibitors in mgcl2 solution is generally agreed to be adsorption on the metal surface. this involves the assumption that the corrosion reactions are prevented from occurring over the area (or active sites) of the metal surface covered by adsorbed inhibitor species, whereas these corrosion reactions occurred normally on the inhibitor-free area [11]. accordingly, the fraction of surface covered with inhibitor species can be taken as a function of inhibitor concentration and solution temperature. the surface coverage (θ) data are very useful while discussing the adsorption characteristics. when the fraction of surface covered is determined as a function of concentration at constant temperature, adsorption isotherm could be evaluated at equilibrium condition. the dependence of the fraction of the surface covered θ on the concentration c of the inhibitor was tested graphically by fitting it to langmuir’s isotherm, which assumes that the solid surface contains a fixed number of adsorption sites and each site holds one adsorbed species. fig. 4 shows the linear plots for c/ θ versus c with r 2 = 0.97 as correlation coefficient, suggesting that the adsorption obeys the langmuir’s isotherm: c/ θ =1/k +c …(3) where c is the equilibrium inhibitor concentration, k adsorption equilibrium constant, representing the degree of adsorption (i.e. the higher the value of k indicates that the inhibitor is strongly adsorbed on the metal surface), the average value of k was 2.25 l/g which was obtained as the reciprocal of intercept of langmuir line, and the slop of this line is nearly 0.5 meaning that each inhibitor molecule occupies half active site on the metal surface. corrosion inhibition of mild steel by curcuma extract in petroleum refinery wastewater 14 ijcpe vol.15 no.3 (september 2014) -available online at: www.iasj.net fig. 4: longmuir adsorption isotherm for extracted curcuma on mild steel table 4: a longmuir adsorption isotherm for curcuma extract on mild steel inhibitor conc. (c) ml/l mgcl2 soln. c/ θ for 0.05% mgcl2 c/ θ for 1.025% mgcl2 c/ θ for 2% mgcl2 1 9.71 10.43 28.65 3 14.24 22.77 57.06 5 25.05 30.74 58.84 7 37.74 41.74 56.63 9 54.99 56.99 79.58 the effect of temperature an attempt was made to find the effect of temperature on the corrosion rate of mild steel in refinery waste water. table 5 shows the corrosion rate of mild steel in different concentrations of wastewater at different temperatures. table 5: corrosion rate of mild steel in different concentrations of wastewater at different temperatures mgcl2 (wt%) temperature 25 °c 30 °c 35 °c 40 °c e(cal/g mol) 0.05 3.06 4.93 5.16 5.56 6855 1.025 2.92 4.42 4.58 5.46 7133 2 2.78 4.02 4.35 5.43 7765 the activation energy was calculated by plotting log c.r versus 1/t from the arrhenius equation c.r = a exp (-e/rt) …(4) where a = constant, r= gas constant, e=activation energy and t=temperature in k. as shown in figure 5, the rate of mild steel corrosion increased with increasing solution temperature, and the activation energy obtained was 7.76 kcal/mol. the small value of the activation energy (7.76 kcal/mol) shows that the corrosion of mild steel in mgcl2 solutions is a diffusioncontrolled process [12]; i.e. the rate of mild steel corrosion is controlled by the diffusion of o2 from the solution bulk to the metal surface (figure 6). this was consistent with previous studies [13, 14, 15], which reported that the corrosion of steel in the ph range 4-10 is controlled by the rate of diffusion of dissolved o2 from the solution bulk to the metal surface. increasing the solution temperature increases the rate of corrosion (figure 7), primarily as a result of increased reaction kinetics, perhaps assisted by a reduction in the viscosity of the solution, with a consequent increase in the o2 diffusivity, according to the stokes-einstein equation [16]: 0 10 20 30 40 50 60 70 80 90 0 10 20 30 40 0.05 wt% mgcl2 1.025 wt% mgcl2 2 wt% mgcl2 aprael s. yaro and kabas f. talib -available online at: www.iasj.net ijcpe vol.15 no.3 (september 2014) 15 dµ/t = constant …(5) where d=diffusion coefficient and µ= solution viscosity. in view of this, all effects that tend to increase the rate of transfer of dissolved oxygen from the solution to the metal surface, such as stirring, vibration, solution flow, etc. tend to increase the rate of corrosion. fig. 5: arrhenius plot of the experimental results at different mgcl2 concentration fig. 6: diffusion layer through which o2 diffuse from the solution bulk to the steel surface [12] y = -3450.3x + 12.815 y = -3590.1x + 13.199 y = -3908x + 14.19 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 0.003180 0.003230 0.003280 0.003330 0.003380 0.05 wt%mgcl2 1.025 wt% mgcl2 2 wt% mgcl2 ln c.r 1/t (k-1) corrosion inhibition of mild steel by curcuma extract in petroleum refinery wastewater 16 ijcpe vol.15 no.3 (september 2014) -available online at: www.iasj.net fig. 7: effect of concentration of mgcl2 on the rate of corrosion at different temperatures the effect of temperature in presence of the inhibitor an attempt was made to find the effect of temperature on the corrosion rate of mild steel in refinery wastewater in presence of the inhibitor. table 6 shows the corrosion rate of mild steel in different concentrations of wastewater at different temperatures with the maximum concentration of the extracted curcuma 9 ml/250ml mgcl2 solution. the activation energy was calculated by plotting log c.r versus 1/t from the arrhenius equation. as shown in figure 8, the rate of mild steel corrosion increased with increasing solution temperature, and activation energy obtained was 5 kcal/mol. the inhibition efficiency of the maximum concentration of the extracted curcuma (9 ml/250ml mgcl2 solution) with different concentrations of mgcl2 solution at different temperatures is presented in table 7. fig. 8: arrhenius plot of the experimental results at different mgcl2 concentrations with existing of extracted curcuma 9 ml/250ml mgcl2 soln 2.0 3.0 4.0 5.0 6.0 0 0.5 1 1.5 2 2.5 25 c 30 c 35 c 40 c mgcl2 concentration (wt%) c.r (gmd) y = -2537.5x + 8.7351 y = -2539.9x + 8.8482 y = -2675.6x + 9.6241 0 0.2 0.4 0.6 0.8 1 1.2 0.00318 0.0032 0.00322 0.00324 0.00326 0.00328 0.0033 0.00332 0.05 wt% mgcl2 1.025 wt% mgcl2 2 wt% mgcl2 1/t (k-1) ln c.r aprael s. yaro and kabas f. talib -available online at: www.iasj.net ijcpe vol.15 no.3 (september 2014) 17 table 6: corrosion rate of mild steel in different concentrations of wastewater at different temperatures with extracted curcuma 9 ml/250ml mgcl2 solution mgcl2 (wt%) temperature 30 °c 35 °c 40 °c e(cal/ gmol) 0.05 4.9263 5.1556 5.5556 5042 1.025 4.4162 4.5828 5.4577 5046 2 4.0235 4.3538 5.4255 5316 table 7: inhibition efficiency of the optimum concentration of extract curcuma (9 cc/250ml mgcl2soln.) at different temperatures mgcl2 wt% temperature 30 ° c 35 ° c 40 ° c 0.05 70.65 68.66 65.98 1.025 63.17 61.8 61.02 2 45.24 40.95 45.16 conclusions 1. the green corrosion inhibitor made up by the curcuma extract successfully reduced the corrosion rates of mild steel in simulated refinery wastewater. 2. in presence of curcuma extract, the inhibition efficiency values generally increased with the inhibitor concentration, but decreased with rise in mgcl2 %wt at constant temperature. it is suggested that the absorption process was more favored at lower mgcl2% concentration. 3. the langmuir adsorption isotherm provided a formal description of the adsorptive behavior of the curcuma extract on mild steel surface. the values of kads. indicated that inhibitor molecules occupied effective sites on the metal surface. references 1b. bavarian, l. reiner, “corrosion protection of steel rebar in concrete with optimal application of migrating corrosion inhibitors”, mci 2022, 2–3, (2003). url:www.cortecvci.com/publicati ons/papers/mci_bavarian.pdf. 2nemerow, n.l., “industrial water pollution origins characteristics and treatment”, robert krieger publishing co., malabar, fl, p. 356 (1987). 3salvato, j.a., “environmental engineering and sanitation”, wiley interscience, 3rd ed., wiley, new york (1982). 4fontana, m.g., “corrosion engineering”, mcgraw-hill, new york (1987). 5jones, d.a., “principles and prevention of corrosion”, macmillan, new york (1992). 6erikh, v.n., rasina, m.g. and rudin, m.g., “the chemistry and technology of petroleum and gas”, mir, moscow (1988). 7rajendran, s.ganga sri v, “bull electrochemical”, 21; 367-378 (2006). 8s.a. nosier, "the effects of petroleum refinery wastewater on the rate of corrosion of steel equipment", anti-corrosion methods and materials, vol. 50 iss: 3 pp. 217 – 222, (2003). 9v. johnsirani, j. sathiyabama, s. rajendran and r. nagalakshmi “curcumin dye as corrosion inhibitor for carbon steel in sea water” chemsci trans., (2013). 10morris, r.; smyl, w., electrochemical society journal 136, p.p. 32373248, november (1989). 11l.l. shereir, corrosion, vol. 2, second ed., newnesbutterworths, london, (1977). 12levenspiel, o., “chemical reaction engineering”, wiley, new york (1962). 13 fontana, m.g., “corrosion engineering”, mcgraw-hill, new york (1987). corrosion inhibition of mild steel by curcuma extract in petroleum refinery wastewater 18 ijcpe vol.15 no.3 (september 2014) -available online at: www.iasj.net 14jones, d.a., “principles and prevention of corrosion”, macmillan, new york (1992). 15uhlig, h., “corrosion and corrosion control”, wiley, new york (1963). 16cussler, e.l. (n.d.), “diffusion mass transfer in fluid systems”, cambridge university press, cambridge (1980). -ljill l-iar i-!i-].s]. i i-)rc qllrl l\li 5-1 (2007 iji) 1 $jr 8 jrr iicpt rf.ll lalla.r .,i -. .1.ill ot+ ley e+c thlill {,iu &l'! r'ilj jtj ijl"j ti st-at 4;t t-dtill t& rr): <j).r 6ill di\.i qi; oucjl !r 4r:ijlj lil rw !l-ls' 'ill ii'lr':<llr 'rlllil' i olislri d'!l l:5il {j"-i ij-ll c. l4!ju.r (lrjr.ll) -. -}ill .ur (rn) j+il '\+ al".,. .rf cf! fjlr 'lsjllj t|jll cf ds a:i; 'j4u uiw 1;t1!l !4ii! .t-r.ll lrlsll ;jjl af 'ls lru dn-,i rii 4r!.511 cjli-lll ul !i d.\jcl dju '\+ll 'jjs' l/e5 lrljtxl 6li-l!l c'l-! jl' a r . , i r , l j ; 1 , t s t , l ! , i j r i # o . $ d a i l : y ! r l r s l r + j i 5 l l r . r * + j l r . r " ' j s i o ' d s 5 j 5 . ' . j } " i 3 1 ' : ' u r i i s c l s + .{jr-ll !-.rll ul' l.ijalsil, f 6lj.'3j & ar6r oj.,in f'-r rjij-f! 'rj-'3'yl llll d"!l asir''isil .:rujyil ''l+j (ru-ljf "li.ll lrj" ; 4'ltl'jl 'l'jsl !,,i 4.,1ru a\!i, j.n ,jl (e. c.) 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4 8l l 7 6 l 1 8 5 564562 9.5 l 0 2000 500 200 t 5 0 600 0.2 1 5 0 0 9.2 0 9 0 7 7 t 6 0 t 3 6 5 9 t l 4 0 5 5 1 5 4 t 7 2 , t 6 l 1 6 6 0 . i 5 0 . 1 5 0 , 1 4 o . t 4 1009 t0 t2 839 a44 0 0 0 0 (2007 jl]i) 1 $jr 8 rlj riil lljal lrrrr+<lt llc l€tlr tt-ll '')ll-----6ill l. water and wasle water technology' mark j hamm€r' join wiley 1975 2.undp trqiga\20ol f j+l r '!'! lli ;t:t'$ +,,! rjt"'r 'u 3 . s t a n d a r d m e l h o d f o r t h e € x a m i n a l i o n , o f w a t e r a n d ' \ { a s t e w a r e r , l 5 t h e d i t i o n i 9 8 0 . a p h a a w w a ' w p c f a ini.marionat slandards for drinking waler 3rd edition' w h o , g e n e v a l 9 7 l dd-l-jjr d,u-ltl {+ o. irlj 4t? alr r-!uli ii-lll 5 ' 1974 j+ ipjj! !r+d l-5j}j3jl .:,r'--i6ll olr laa rfr dp fj.$ \.-lj: l !f ilc aul| d"jir o!j,l,r]* .r.r u: ,rfll flfl !f 4, (coli fo(m) !-jl g-1" irjrkiil .lj dl $. ll.j)r (e-coli) 'ul sr 3l-l.5j vj i--+itj .ll.lr .j €,u!' .--,iil (n agar) +\jl gl--,)-t:j o}:-jl r!ljrsj t_.jl 'iii dli;jij rulll rt--i.x, l ii-l.rll ; \c c j.jr rll o*r':.lrj ;fjl i l l 4 9 5 0. i ( (2007 jlll) 1 i-i 8 jill j.iil i'!ra., lrrlr'fil 1!ic liljjl rljt iraqi journal of chemical and petroleum engineering vol.17 no.3 (september 2016) 109116 issn: 1997-4884 sorption of nitrate salts from wastewater without and with modification orange peel zainab abdulrazak n. environmental engineering department–college of engineeringـــ university of almustansiriyah abstract this investigation deals with the use of orange peel (op) waste as adsorbent for removal of nitrate (no3) from simulated wastewater. orange peel prepared in two conditions dried at 60c° (opd) and burning at 500 °c (opb). the effect of ph: 2-10, contact time: 30180 min, sorbent weight: 0.53.0 g were considered. the optimal ph value for no3 adsorption was found to be 2.0 for both adsorbents. the equilibrium data were analyzed using langmuir and freundlich isotherm models. freundlich model was found to fit the equilibrium data very well with high-correlation coefficient (r 2 ). the adsorption kinetics was found to follow pseudo-second-order rate kinetic model, with a good correlation (r 2 > 0.95 and 0.94) for the orange peel adsorbent at 500 °c (opb) and at 60 °c (opd), respectively. the results showed that the orange peel was found to be an attractive low cost adsorbent for the treatment of wastewater. keywords: orange peel (op); nitrate; sorption; isotherms; kinetics; wastewater. introduction nitrate contamination in surface and ground water has become an increasingly important problem for all over the world. although nitrate is found in moderate concentrations in most of the natural waters, higher levels in ground water mainly result from human and animal waste, and excessive use of chemical fertilizers. the other most common sources of nitrate are uncontrolled land discharges of municipal and industrial waste waters, overflowing septic tanks, processed food, dairy and meat products, and decomposition of decaying organic matters buried in the ground [1,2]. the high concentration of nitrate in drinking water leads to the formation of nitrosoamine, which is related to cancer and increases the risk of diseases such as methanoglobinemia in newborn infants [3,4]. nitrate is more toxic than nitrite and can cause human health problems such as liver damage and even cancers. nitrate can also bind with hemoglobin and create a situation of oxygen deficiency in infant’s body called methemoglobinemia. nitrite, however, can react with amines chemically or enzymatically to form nitrosamines that are very strong carcinogens [5]. for removal nitrate from wastewater, adsorption has become one of the most economic and effective method. the process is superior to many other methods of water reuse by virtue of its low initial cost, low energy requirements, simplicity of design and university of baghdad college of engineering iraqi journal of chemical and petroleum engineering sorption of nitrate salts from wastewater without and with modification orange peel www.iasj.netavailable online at: 6) 201 september( 3no. 7ijcpe vol.1 111 possibility of reusing the spent carbon via regeneration [9]. adsorption in general, is the process of collecting soluble substances that are in solution on a suitable interface. in the past, the adsorption process has not yet been used extensively in wastewater purification but demands for a better quality of treated wastewater effluent have led to an intensive examination and use of the process of adsorption on adsorbents. adsorbent is a very expensive adsorbent for the removal of pollutant so other inexpensive adsorbents must be investigated [10,11]. in recent years, agricultural byproducts have been widely studied for no3 salts removal from water. these include peat, wood, pine bark, banana pith, soybean and cottonseed hulls, peanut, shells, hazelnut shell, rice husk, sawdust, wool, pomegranate rind and compost and leaves [6]. the use of orange peel as a biosorbent material presents strong potential due to its high content of cellulose, pectin (galacturonic acid), hemicellulose and lignin. as a low cost, orange peel is an attractive and inexpensive option for the biosorption removal of dissolved metals. ajmal et al. employed orange peel for metal ions removal from simulated wastewater [7,8]. therefore, the present study was undertaken to produce adsorbent by thermal and physical activation process utilizing orange pe as abundant local raw material for application in efficient nitrate removal. the effects of various operating conditions, namely, ph of solution, initial concentration of anions, contact time, and temperature, were investigated. used sulfur and limestone for nitrate removal from potable water in a batch study. materials and methods 1. sorbent preparation orange peel adsorbent (op adsorbent) was collected from a local juice manufacturing industry. op was cut into small pieces, dried in an oven at 60 °c for 24 h and crushed. the powdered orange peel was washed with hot water and dried in an oven at 60 (opd) and burning in the furnace at 500 °c for 12 h (opb). after drying they were sieved to particle size 0.5 mm, and used as an adsorbent. 2. chemicals no3 solutions were prepared by diluting 1000 ppm of kno3 potassium nitrate (scharlau (30 % wt/wt)) stock solution with demonized water to a desired concentration range between 25 and 200 mg/l. before mixing the adsorbent, the ph of each test solution was adjusted to the required value with diluted and concentrated hcl and naoh solutions, respectively. insignificant decreases in the final equilibrium ph were recorded, so during the uptake ph was assumed constant. 3. adsorption procedure batch adsorption experiments were carried out by agitating 1 g of the orange peel with 100 ml of no3 solutions of desired concentrations and ph at room temperature using an orbital shaker operating at 200 rpm. the effect of ph was studied by adjusting the ph of the solutions using (1n) hcl or (1n) naoh solution. the effect of initial salts concentrations was carried out by shaking 100 ml no3 solutions of desired concentrations (25, 50, 75, 100, 150 and 200 mg l −1 ) with 1 g of the adsorbent. all the samples were adjusted to the optimum ph prior to the addition of the adsorbent. the http://www.iasj.net/ zainab abdulrazak n. 111 )6201september ( 3no. 17ijcpe vol. www.iasj.netonline at: available samples were withdrawn from the shaker at pre-determined time intervals and no3 solution was separated from the adsorbent by centrifugation at 4000 rpm for 20 min. blank runs, with only the adsorbents in 100 ml of doubledistilled water, were conducted simultaneously at similar conditions to account for any color leached by the adsorbents and adsorbed by glass containers. all the investigations were carried out in duplicate to avoid any discrepancy in experimental results and salts solution controls were kept throughout the experiment to maintain quality control. the percentage of salts adsorption by the adsorbents was computed using the equation [2]: ( ) …(1) where, = initial no3concentration in sample (mg/l) = equilibrium no3 concentration in sample (mg/l). result and discussion 1. characteristics of the adsorbents the chemical structure of this orange peel adsorbent is shown in table 1. table 1: chemical composition of the (op) by x-ray fluorescence analysis characteristic values cao k2o so3 mgo fe2o3 sio2 p2o5 bao sro al2o3 nio organic matter 1.43% 0.17% 0.15% 0.11% 0.12% 0.09% 0.06% 0.01% 0.02% 0.02% 0.01% 97.83% 2. effect of ph the effect of ph on removal efficiency of nitrate by op is shown in figure 1. the removal efficiency of op prepared at 60 °c (opd) and op burned at 500 °c (opb) was decreased from 90 to 20 % and 95 to 71 %, respectively, when the initial ph of the aqueous solution was increased from ph 2 to 10. the nitrate content was decrease in the ph range of 2–6. however, removal efficiency for both op adsorbents was increased to 88% for opd and 95% for opb adsorbent, when the ph remained constant at ph 2. though there is increase in oh – concentration at increased ph, yet removal efficiency of no3 decrease. this may probably due to the preferential adsorption of nitrate. among oh and no3, affinity of op adsorbent 500 °c for no3 is greater than (oh ) [13]. fig. 1: removal of no3 by opd and opb at dosage 1% (w/v), initial concentration 50 mg/l, temp. 25 o c, ph 2, agitation speed 200 rpm and contact time 3 h 3. fourier-transform infrared analysis (ftir) infrared spectra of orange peel (op) samples before and after nitrate ions binding were examined using (shimadzu ftir 8000 series spectrophotometer). the functional groups have been identified in figure 2 (a-c). as seen in these figures the http://www.iasj.net/ sorption of nitrate salts from wastewater without and with modification orange peel www.iasj.netavailable online at: 6) 201 september( 3no. 7ijcpe vol.1 111 spectrum pattern of loaded op showed changes in the peak absorption as compared to unloaded op which result from adsorption process. contribution of each functional group in this process is summarized in tables 2 and 3. fig. 2: functional groups (a) before op loaded without no3 salts (b) after opd loaded with no3 salts (c) after opb loaded with no3 salts table 2: ftir functional groups for opd wave number (cm -1 ) assignment groups after adsorption of no3 3398.57 carboxylic acid, amides 3402.43 1627.92 amines, alkenes 1631.78 1435.04 carboxylic acid, alkenes 1438.90 1161.15 ketones, amines, alkyl halides 1165.00 725.23 alkyl halides, aromatic 756.10 609.51 alkyl halides, alkyanes 628.79 586.36 alkyl halides 597.93 table 3: ftir functional groups for opb wave number (cm -1 ) assignment groups after adsorption of no3 3398.57 carboxylic acid, amides 3410.15 2927.94 carboxylic acid, alkanes 2935.66 1033.85 carboxylic acid 1064.71 894.97 alkenes 898.83 756.10 aromatic 759.95 667.37 aromatic 671.23 559.36 alkyl halides 590.22 4. effect of sorbent dose the sorbent amount is one of the important parameters used to obtain the quantities uptake of no3 salt .the sorbent amount was studied by varying the quantity of op adsorbent (0.5, 1, 1.5, 2, 2.5, 3) g in 100 ml of 50 mg/l of no3 solution. sorption of no3 was increased as the sorbent amount increased. the results were expected because for a fixed initial no3 concentration, increasing adsorbent amount provides greater surface area or sorption site, this result agreement with those obtained by other researchers [12]. the higher removal efficiency was achieved by using 2 g/100 ml sorbent dosages. the removal efficiency of opd adsorbent and opb adsorbent was increase from 89 to 97% http://www.iasj.net/ zainab abdulrazak n. 111 )6201september ( 3no. 17ijcpe vol. www.iasj.netonline at: available and 85 to 91%, respectively, as show in figure 3. fig. 3: removal of nitrate by opd and opb with different contact time, initial concentration 50 mg/l, adsorbent dosage: 2% w/v temperature 25°c, ph= 2; agitation 200 rpm 5. effect of contact time the effect of contact time on the removal of nitrate by opd and opb was observed to increase as contact time increased as shown in figure 4 the concentration of nitrate using odb was decreased substantially from initial concentration of 50– 17mg/l within 1h of treatment where the removal efficiency was around 66% . for op adsorbent, the percentage removal during the first hour was 58% , the initial concentration of 50mg/l was decreased to 21 mg/l. the final concentration of nitrate adsorbed by both samples reached equilibrium point within 2h of operation. fig. 4: removal of nitrate by op adsorbents with different contact time, initial concentration 50 mg/l, adsorbent dosage: 2% w/v temperature 25°c, ph= 2; agitation 200 rpm and ph= 2 6. adsorption isotherms in order to find an equation which suitable for the results and can be used for design purposes; langmuir and freundlich isotherm equations have been used for the equilibrium modeling of adsorption systems. the form of langmuir (linear form) is: …(2) where ce is the equilibrium concentration of the metal in solution (mg/l), qe is the amount absorbed at equilibrium (mg/g), qo (mg/g) and k (l/mg) are langmuir constants related to sorption capacity and sorption energy, respectively. maximum sorption capacity (qo) represents monolayer coverage of sorbent with sorbate and b represents the enthalpy of sorption and should vary with temperature. a linear plot was obtained when ce/qe was plotted against ce over the entire concentration range of metal ions investigated. the freundlich adsorption form (linear form) is: …(3) where qe is the amount of metal ion adsorbed at equilibrium per gram of adsorbent (mg/g), ce is the equilibrium concentration of metal ion in the solution (mg/l), kf and n are the freundlich model constants [13]. freundlich parameters, kf and n, were determined by plotting log qe versus log ce. the langmuir and freundlich adsorption isotherms of nitrate ions are given in figures 5, 6 and table 4. http://www.iasj.net/ sorption of nitrate salts from wastewater without and with modification orange peel www.iasj.netavailable online at: 6) 201 september( 3no. 7ijcpe vol.1 111 fig. 5: langmuir plots of no3 sorption on (a) opd (b) opb fig. 6: freundlich plot of no3 sorption on (a) opd (b) opb table 4: langmuir and freundlich constants for adsorption of no3 onto op adsorbent isotherm models langmuir r² a b opd 0.114 26.31579 0.017707 opb 0.612 16.12903 0.087694 freundlich adsorbent r² 1/n k opd 0.829 0.838 0.572796 opb 0.918 0.702 1.503142 these results showed that in both case (opd or opb) the best model is freundlich. 7. kinetic modeling two kinetic models namely pseudo-first-order, and pseudo-secondorder models have been discussed to identify the rate and kinetics of adsorption of nitrate on prepared orange peel adsorbent. the linear form of pseudo-first-order (lagergren rate equation) equation is given in eq. 4 [14]: ( ) …(4) and the linear pseudo-second-order model is given as: ( ) …(5) where qeq is the amount of metal sorbed at equilibrium (mg/g); qt is the amount of metal sorbed at time t (mg/g); and k1; k2 is the equilibrium rate constant of pseudo first sorption (1/min). figure 7 (a, b) show a plot of pseudofirst and second-order kinetic model of nitrate adsorption on prepared adsorbent (for unmodified and modified), compiled in table 3 along with correlation coefficient (r 2 ) values. it is seen from table 5 that the theoretical qe (cal) values calculated from the pseudo-first-order model did (b) http://www.iasj.net/ zainab abdulrazak n. 111 )6201september ( 3no. 17ijcpe vol. www.iasj.netonline at: available not give reasonable values with regard to the experimental uptake ones, qe (exp). further, the correlation coefficient (r 2 ) is less than 0.99 suggesting that the present adsorption system does not follow pseudo-firstorder process (in both case), while pseudo-second-order model is the best to describe our study. table 5: comparison of sorption rate constants, experimental and calculated qe values for the pseudofirst and second-order reaction kinetics for component systems adsorbent pseudo-first-order qe exp. k1 1/min qe calculated r 2 mg/g mg/g opd 2.275 -0.025 1.8022 0.825 opb 2.425 -0.021 1.4903 0.857 adsorbent pseudo-second-order k2 g/mg.min qe calculated r 2 mg/g opd 0.01825 0.954 opb 0.03185 0.972 fig. 7a: pseudo-first order kinetic for adsorption of no3 on op fig. 7b: pseudo-second order kinetic for adsorption of no3 onto op conclusion the results show that the adsorption of nitrate using orange peel occurred at wide range of concentrations. the time required for utilizing nitrate varies between 30-180 min depending on the initial concentration nitrate. the time of utilization increases as the initial concentration of nitrate increase.. the isotherm equilibrium studies confirmed that the freundlich form and generalized models were the highest fitted models for the both adsorption process. orange peel adsorbent which is dried at 500 °c was the best fitted than orange peel adsorbent which is dried at 60 °c. the maximum adsorption potential of orange peel adsorbent for no3 salts removal was 2.532 mg/g. pseudosecond-order reaction kinetic has provided a realistic description of removal of no3 salts with closer experimental and calculated values of uptake capacity. also correlation coefficients are higher in pseudosecond-order kinetics. references 1. a.h. wolfe, j.a. patz, reactive nitrogen and human health: acute and long-term implications, ambio ,31,pp. 120–125(2002). 2. m.n. almasri, j.j. kaluarachchi, assessment and management of longterm nitrate pollution of http://www.iasj.net/ sorption of nitrate salts from wastewater without and with modification orange peel www.iasj.netavailable online at: 6) 201 september( 3no. 7ijcpe vol.1 111 ground water in agriculture dominated watersheds, j. hydrol., 295 ,pp. 225–245(2004). 3. h. bouwer, agricultural contamination: problems and solutions, water environ. technol. ,10,pp. 292–297(1989). 4. water environment federation; american society of civil engineers; environmental and water resource institution (wef, 2005), biological nutrient removal (bnr) operation in wastewater treatment plants, manual of practice no. 30, wef press and mcgraw hill, usa. 5. sawyer, c. n.; mccarty, p. l.; parkin, g. f. , chemistry for environmental engineering and science, 5th edition, mcgraw hill publishing, new york, pp663(2003). 6. hasar h. adsorption of nickel(ii) from aqueous solution onto activated carbon prepared from almond husk. j. hazard. mater. ,97,pp. 49–57(2003). 7. wan ngah ws, hanafiah makm ., removal of heavy metal ions from wastewater by chemically modified plant wastes as adsorbents: a review. bioresour technol ,99,pp.3935–3948(2007). 8. ajmal m, rao, ahmad rakr, ahmad j., adsorption studies on citrus reticulata (fruit peel of orange): removal and recovery of ni (ii) from electroplating wastewater. j. hazard. mater. b.,79,pp. 117–131(2000). 9. namasivayama, c. and kadirvelu, k., “activated carbon adsorption of cd(iii) from queous solution”, adv. env. research, 7(2),pp. 471478(2003). 10. t.e. bektas, master of science thesis, investigation of efficiency of sepiolite and other adsorbents for dyestuff and ome anions removal, chemical engineeri department,osmangaziuniversity, turkey, 2000. 11. w.j. weber, physicochemical processes for water quality control, wiley, new york, pp. 638(1972). 12. ferda gönen* and d. selen serin, adsorption study on orange peel: removal of ni(ii) ions from aqueous solution.,, african journal of biotechnology vol. 11(5), pp. 1250-1258, ( 2012). 13. p.c. mishra a , m. islam a & r.k. patel b ., " removal of nitrate—nitrogen from aqueous medium by adsorbents derived from pomegranate rind", desalination and water treatment, 1944-3994 ,pp.1944-3986(2013). 14. heidari a, younesi h, mehraban z ., removal of ni (ii), cd (ii), and pb (ii) from a ternary aqueous solution by amino functionalized mesoporous and nanomesoporous silica. chem. eng. j., 153,pp. 70–79(2009). http://www.iasj.net/ ijcpe vol.9 no.4 (2008) iraqi journal of chemical and petroleum engineering vol.9 no.4 (december 2008) 4149 issn: 1997-4884 design criteria of an activated carbon bed for dechlorination of water muna y. abdul – ahad environmental engineering department college of engineering university of baghdad – iraq abstract granular carbon can be used after conventional filtration of suspended matter or, as a combination of filtration adsorption medium. the choice of equipment depends on the severity of the organic removal problem, the availability of existing equipment, and the desired improvement of adsorption condition. design calculations on dechlorination by granular carbon filters considering the effects of flow rate, ph , contact time, head loss and bed expansion in backwashing , particle size, and physical characteristics were considered assuming the absence of bacteria or any organic interface . key words: activated carbon, dechlorination, water purification. introduction theory granularactivated carbon adsorption is a reliable and effective means of removing most organic impurities found in potable water supplies. plant operations and pilot column studies have shown carbon filtration to be an effective process for removing detergents (flentje, 1964), insecticides, (robeck, 1965), viruses (robeck, 1964), specific chemical pollutants, (dostal, 1965), and taste and odor pollutants (flentje, 1964). these results confirm postulations that carbon bed filtration would remove a high percentage of undesirable organic contaminants from water efficiently over a wide range of impurity concentration conditions. the utilization of granu1arcarbon filtration is a relatively simple and economical procedure. it is possible to adopt existing plant filters for a combination filtration adsorption unit process with minimum alteration, by filling them with granular carbon. tests (joyce, 1966) had shown that, in accordance with adsorption theory, granular carbon in beds is more efficient than pulverized carbon used in slurry form in accordance with conventional water plant procedures. this advantage compensates for the cost differential of pulverized carbon and granular carbon applied on a single use basis. filtration – adsorption: the capacity of granular activated carbon for removing viruses has been studied by (rebeck et al, 1964), who found that in clear water poliovirus was removed much more readily by beds of fresh carbon than by sand beds. activated carbon, even if its adsorption capacity was exhausted, still removed slightly more virus than did the beds of sand, however. suitably abrasionresistant granular activated carbons can serve both as filter media and adsorbent. (smith and skeel, 1964), have reported that granular carbon beds are serving such a dual role in several locations (eld, e.f., 1961) . filters with fresh carbon were placed in service along with similar sand medium filters. the carbon beds were (24 in.) deep and were tested for both adsorption and filtration at conventional sand filter rates. the results are summarized in (table 1) (smith and skeel, 1964). for (60) days the carbon filters reduced threshold odor from (70 to 4). at the same time, they reduced turbidity to less than (0.07 jackson units), a performance somewhat superior to that of the sand filters. super university of baghdad college of engineering iraqi journal of chemical and petroleum engineering design criteria of an activated carbon bed for dechlorination of water 42 ijcpe vol.9 no.4 (2008) chlorination preceded the filtration, and free residual chlorine was reduced from ( 1.4-2.8ppm) to less than ( 0.25ppm) .after their odor removal capacity was exhausted , the carbon filters continued to produce water that, in regard to its color and to iron, manganese, chlorine, and turbidity content was of a quality equivalent to or better than that produced by sand filters. chlorine: granular activated carbon has long been used for the removal of residual chlorine from water. as super chlorination finds wider accepter in the public water supply industry, means of dechlorination are required. dechlorination by granular carbon is extremely effective and reliable. because the granular activated carbon acts principally as a catalyst for the reduction of hypochlorous acid to chloride ion, the capacity of the carbon is determined not by normal adsorption parameters but by other considerations. 222 422 cohclohccl  or oclhohcl   22 22 the chemisorbed nascent oxygen decomposes in either of the following two ways. cococ xx  2 cococ xx  this takes place on the surface of the carbon. (magee, 1956), studied the carbon chloride system in great detail to postulate a relationship between flow rates, bed depth, concentration of influent and effluent chlorine, as well as the granular carbon itself. also (gulp, g.l., 1974) gave the following equation. v b ftsqgpmratefiltration ftdepthbedb c c log b i    )/( )( tests (fairm, geyerm, and oukun, 1971), had determined efficiency values for specific carbons available to industrial and municipal treatment operations in the united states. their results for flow rates, concentration of influent and type of carbon are shown in (fig.1) (fairm, geyerm, and oukun, 1971).they are based on chlorine breakpoint of (0.01 ppm). the life of the carbon in dechlorination service is extremely long. example: under conditions of sand filter service ( that is 2.5 gpm /sq ft and 2.5 ft bed depth) , granular carbon medium in a ( 1 mgd) filter (700 cu ft ) on dechlorination service alone could process (700 mi1 gal) of ( 4 ppm ) free chlorine influent water before a breakpoint of (0.01 ppm) chlorine would be reached . a bed processing water containing (2ppm) chlorine under similar conditions would last about (6 years). the effect of mesh size is pronounced. as indicated in ( fig .1) (fairm , geyerm, and oukun,1971) , a reduction in particle size reflected in the reduction of mesh size from (8x30) to ( 14x40) allows a doubling of flow rate without a sacrifice in efficiency. dechlorination will proceed concurrently with adsorption of organic contaminates. long chain organic molecules, such as those of detergents, will reduce dechlorination efficiency somewhat, but many common water impurities, such as phenol, have little apparent effect upon the dechlorination reaction. a rise in temperature and a lowering of (ph) favor dechlorination. (fig. 2)(fairm, geyerm, and oukun, 1971) indicates the relationship of these factors as they vary from (ph7) and 21°c. mesh size (8 x 30) and flow rate was (l gpm / ft3). a break-point of (0.01 ppm) cl2 and the absence of bacteria or any organic interference were assumed. it is unlikely that a deliberate change in ph or temperature favoring dechlorination alone would be economically feasible, unless existing conditions significantly retard the process. these data are theoretic values determined with chlorine in distilled water. variance in hydraulic loading, suspended matter, and certain adsorbed organics, as noted above, could adversely affect dechlorination efficiency. design criteria granular carbon can be used after conventional filtration of suspended matter or, as a combination filtration adsorption medium. the choice of equipment depends on the severity of the organic contaminants (detergents, insecticides, viruses, specific chemical pollutants, and taste and odor pollutants) removal problem, the availability of existing equipment, and the desired improvement of adsorption conditions. usually two or more units are used in parallel down flow operation. the start-ups of the units are staggered so that exhaustion of each bed will be in sequence. b1ending of the fresh carbon effluent with partially exhausted carbon muna y. abdul – ahad 43 ijcpe vol.9 no.4 (2008) effluent in effect prolongs the life of the bed before reactivation or replacement of the individual beds is necessary. flow rates are usually (2.5-5gpm/sq.ft), and bed depths are normally (2.5-10 ft) .varying the combined values of these two factors can be thought of as adjusting the contact time of the water and the granular carbon beds. a direct linear relationship between contact time and carbon bed-performance was found at the nitro faci1ity in full scale plant tests and concurrent small co1oumn tests. during these tests flow rate conditions were (3.7 gpm / sq ft 10gpm/sq ft) and bed height (5-20 ft). (fig.3) (dostal et al, 1965) shows the relationship of contact time and performance. when bed depths at given flow rates are reduced to a contact time function (gpm / cu ft), the performance is directly proportional to this function. when the granular carbon bed is functioning both as a turbidity removal and adsorption unit, there may be reasons to limit the bed depth and flow rate parameters to remove effectively turbidity and to backwash properly the filter. if granular activated carbon is to be effective in turbidity removal, it must be hard enough to withstand vigorous backwash agitation. at the same time, it should be dense enough to expand during the backwash cycle and to settle quickly for immediate resumption of filtration. backwash expansion data, head loss, and physical characteristics of coalbased granular carbon are presented in (figs. 4 & 5) and (table 2) (magee, 1965). particle size of the carbon, in addition to contact time, should be considered carefully as a design factor. reduction of particle size for a given set of flow conditions is recognized to be a means of increasing adsorption rates and, thereby, improving adsorption performance. this phenomenon has been explored by many authors, including, (weber and morris, 1965). reduction in particle size to improve adsorption must be consistent with other significant factors, such as head loss and backwash expansion. length of filter run in an adsorption -filtration bed would also be a problem, if too small a particle size were chosen. in a study(weber and morris,1965) of the effect of particle size, bed depth, and flow rates on the performance of an abs system, three sets of three columns in series, containing three mesh size carbons, were examined at bed depths (2.5, 5, & 7.5 ft). the three mesh size carbons were approximately the same in all respects except particle size. (table 3) (weber and morris, 1965) summarizes the results. at shallow bed depths, the smallest particle size demonstrates its rapid adsorption rate. at the deeper bed depths and longer contact periods, however, the difference in performance due to adsorption rate is perhaps significant. a summary of design criteria is given in (table 4) (weber and morris, 1965). design calculations (1) applying equation (2) v b ftsqgpmratefiltration ftdepthbedb c c e i    )/( )( log (a) referring to (fig. 1) and (table 4), the two carbon mesh sizes used are 8x30 and 14x40. (b) calculation of b using (fig. 1) for 8x30 mesh size and 2 gpm / ft3 flow rate. applying v b c c e i log 3 /201.0 1 log ftgpm b ppm ppm  ph= 7 of water, t = 21°c & a break point = 0.01 of cl2 as given by (fig. 1) . :. b = 4 for 8x30 mesh size (c) applying equation again for the actual design flow rate = 44 gpm, influent concentration= 1ppm cl2, effluent = 0.1ppm cl2 3 /4, 4 10.0 00.1 log f tgpmv v  (d)bed volume= 3 /4 44 ftgpm gpm sizemeshforft 30810 3  design criteria of an activated carbon bed for dechlorination of water 44 ijcpe vol.9 no.4 (2008) e) for 14x40 mesh size and using (fig. 1), for 1 gpm ift 3 applying 3 /101.0 2 log,log ftgpm b v b c c e i  b =2.3 for 14x40 mesh size (f) applying equation again for the actual design flow rate = 44 gpm v 3.2 1.0 1 lo g  v =2.3 gpm ift 3 (g)bed volume= 3 /3.2 44 ftgpm gpm =19.13ft3for14x40 mesh size 2) referring to (table 4), which gives a summary of design criteria for granular carbon filtration for rough calculations of height of carbon bed and diameter (l& d) (a) using bed as filtration adsorption from table, flow rate 2.5 gpm i ft2 (a-1) mesh size 8x30 applying equation 2 /sup )( log ftgpmflowrateerficial ftheightbedb c c e i   ftl ftgpm ftl 625.0, /5.2 )(4 1.0 0.1 log 2    (a-2) mesh size l4x 40 f t f t f t d f tl l 75.4 09.1 3.194 09.1, 5.2 3.2 1.0 1 log 3         (b) using bed as adsorption only from table, flowrate = 5 gpm /ft2 (b. 1) 8x30 mesh size ft ftgpm l 25.1 4 /51 2   f t f t d 25.1 104 3     f t19.3 (b-2) 14 x 40 mesh size f t f t f t d f t f tgpm l 37.3 17.2 3.194 17.2 3.2 /51 3 2         (3) expansion of granular carbon bed in back washing at 22°c (3-1) adsorption filtration bed flow rate  2.5 gpm/ft 2 (a) 8 x 30 mesh size using 2.5 gpm i ft 2 from (table 4). %carbon bed expansion  1 % (b) 14 x 40 mesh size % carbon bed expansion  2% (3-2) absorption only bed flow rate =5 gpm i ft 2 (a) 8 x 30 mesh size % carbon bed expansion  2% (b) 14x40mesh size% carbon bed expansion  13% (4) head loss on coal based granular carbon bed of 22°c (4-1) adsorption filtration bed superficial velocity < 2.5 gpm i ft 2 a) 8 x 30 mesh size, using (fig. 5). head loss through bed = 1.5 in. / ft. f t f t f t l bedofvolume d 6.4 )265.0)(( 1044 3        muna y. abdul – ahad 45 ijcpe vol.9 no.4 (2008) (b) 14 x 40 mesh size head loss through bed = 3.5 in. /ft . (4-2) adsorption bed only superficial velocity=5 gpm/ft ft 3 (a) 8 x 30 mesh size head loss through bed = 3 in. i ft. (b) 14 x40 mesh size head loss through bed = 6.5 in. /ft experimental laboratory evaluation to assess the feasibility of using the ac for this application is to put together a liquid phase adsorption isotherm in the laboratory, which also determines the distribution of chlorine the adsorbed phase, and the solution phase at equilibrium. data for the isotherm were obtained by treating a fixed volume of the contaminated liquid in a series of known carbon dosages. the carbon liquid mixture is agitated at a constant temperature for 3 hours. during that time the carbon and liquid reach adsorptive equilibrium, the carbon is removed and the residual contamination in the liquid is measured (degramount 1991, who 1984, white, 1972, water fac. 2000). the adsorption isotherm gives the chlorine contaminant amount remaining in solution. it depicts the ability of graduated amounts of carbon to treat equal volumes of chlorine contaminant solutions under identical conditions, also can be used to compare the relative efficiency of different grades of carbon and to investigate the effects of variables, such as ph and temperature. results are shown in (fig. 6) .as shown, a significant benefit is achieved by reducing particle size from 8 x 30 to 14 x 40 meshes. to estimate the contaminant capacity for calculating the weight of carbon needed for a column, one uses an x i m value that corresponds to the influent concentration (co = 1 ppm). this value, x i mco, represents the maximum amount of contaminant adsorbed per unit weight of carbon when the carbon is in equilibrium with the untreated contaminant concentration. once (x i mco is determined = 1.2 mg ig , for the system from (fig. 6), the theoretical carbon demand for the given volume of chlorine contaminated liquid can be calculated. for complete removal of the chlorine contaminant: y = co i (x i mc0) where y = weight of carbon required per unit volume of chlorine contaminated liquid y = .8333 gm /l table shows the overall calculated design parameters converted to metric system. head loss in . / ft % carbon bed expansion in back washing carbon bed diameter d ft carbon bed depth l ft flow rate gpm / ft 2 carbon bed volume ft 3 eff. carb on const ant b carbon mesh size 1.5 =12.5cm/m 1 4.6 =1.402m .625 =.1905m 2.5 =7.335 m3/m2/h filtration adsorptio n bed 10 =.283m3 4 8x 30 = [mean dia.] 1.5mm 3 =25cm/m 2 3.19 =.972m 1.25 =.381m 5 =14.67 m 3 /m 2 /h adsorpti on bed only 3.5 =29.17cm/m 2 4.75 =1.448m 1.09 =.332m 2.5 =7.335 m 3 /m 2 /h filtration adsorptio n bed 19.3 =.547m3 2.3 14x40 = [mean dia.] 0.9mm 6.5 =54.17cm/m 13 3.37 =1.207m 2.17 =.661m 5 =14.67 m3/m2/h adsorpti on bed only 0.1 1 10 0.1 1 10 100 water filtered-mil gal/cu ft in fl u e n t c h lo ri n e -p p m fig.1: the effect of mass flow rate and mesh size on dechlorination by granular-carbon filters (fairm, geyerm, and oukun, 1971). the ph of the water was 7 and the temperature was 21°c. a breakpoint of 0.01 ppm cl2 and the absence of bacteria or any organic interference were assumed. curve a represents an 8x30 mesh size and a 2 gpm/cu ft flow rate; curve c represents a 14x40 mesh size and a flow rate of 1 ppm/cu ft; curve b represents mesh sizes of 8x30 and 14x40 at flow rates of 1 and 2 gpm/cu ft respectively, and illustrates that such a reduction in mesh size allows a doubling of the flow rate without any sacrifice of efficiency. . design criteria of an activated carbon bed for dechlorination of water 46 ijcpe vol.9 no.4 (2008) 0.1 1 10 0.1 1 10 100 water filtered-mil gal/ cu ft in fl u e n t c o n c e n tr a ti o n -p p m fig. 2: effect of ph and temperature on dechlorination by granular carbon (fairm, geyerm, and oukun, 1971). mesh size was 8 x 30 and flow rate was 1 gpm/cu ft. a breakpoint of 0.01 ppm cl2 and the absence of bacteria or any organic interference were assumed. curve a represents ph 9 and 21°c; curve b, ph 7 and 21°c; curve c, both ph and 21°c and ph 7 and 30 °c 0.1 1 10 0 5 10 15 20 25 30 35 period of threshold odors less than 2-days c o n ta c t t im e -g p m /c u f t fig.3: relationship of contact time to reduction f threshold odor at (nitro, w. va) (dostal et al, 1965). the influent threshold odor during the tests averaged 150. the data points represent the following: a, a 10 gpm/sq ft flow rate at a depth of 5 ft; b, 10 gpm/sq ft flow rate at 10 ft; c, 5 gpm/sq ft at 5 ft; d, 4 gpm/sq ft at 5 ft; e, 10 gpm/sq ft at 15 ft; f, 3.6 gpm/sq ft at 5 ft; and g, 10 gpm/sq ft at 20 ft. 0 20 40 60 80 100 120 0 5 10 15 20 25 superficial velocity-gpm/sq ft c a rb o n b e d e x p a n s io n -p e rc e n t fig 4 expansion of granular-carbon bed in backwashing at 22 c° (magee, 1956). curve a represents a 14x40 mesh size; curve b, an 8x 30 mesh size. 0.1 1 10 0.1 1 10 superficial velocity-gpm/sq ft h e a d l o s s t h ro u g h b e d -i n /f t fig. 5: head loss on coal-based granular bed at 22 °c (magee, 1956). curve a represents a 14x40 mesh size; curve b, an 8x30 mesh size. 1 10 100 1 10 100 1000 chlorine contaminant concentration, ppm c h lo ri n e w e ig h t p ic k u p m g /g fig.6: activated carbon adsorption isotherms. curve a represents a 14x40 mesh size; curve b, an 8x30 mesh size muna y. abdul – ahad 47 ijcpe vol.9 no.4 (2008) table 1. impurity removal by adsorption-filtration carbon beds * and by sand medium (smith and skeel, 1964). *24 in. deep, with flow rate of 2 gpm/sq ft. # odor samples taken over a 60·day period; other samples, over a150·day period t table 2. physical properties of coal-based granular carbon*(magee, 1956). *type mwt: manufactured by the pittsburgh activated carbon co. pittsburgh, pa. *measured by the n2 , bet method. @ backwashed and drained ^ wetted in water. table 3, effect of mesh size and bad depth on detergent (abs) removal*(weber and morris, 1965). * under the following conditions: concentration concentration of abs in influent, 10 ppm; flow rate, 2.5ppm/sq ft; break point,0.5ppm abs; type of carbon, mwt grade. # mean particle # mean particle diameter is 1.5mm. @ mean par @ mean particle diameter is 0.9 mm. weight ^ weight of abs/ weight of carbon table 4. summary of design for granular-carbon filtration (weber and morris, 1965). conclusions from the results obtained above , it is clear that the greater the size of the activated carbon granules used, for a constant flow rate of water, the carbon bed volume, carbon bed depth , carbon bed diameter, % carbon bed expansion in backwashing , and head loss, are of lower percentages assuming chlorine removal only , as shown below. % decrease when using 8x30 mesh size carbon bed granules flow rate gpm / ft 2 head loss in. / ft % carbon bed expansion in back washing carbon bed diameter d ft carbon bed depth l ft carbon bed volume ft 3 57.1% 50% 3.2% 42.7% 2.5% filtration adsorption bed 2.5 =7.335 m 3 /m 2 /h 53.8% 84.6% 5.3% 42.4% 2.5% adsorption bed only 5 =14.67 m 3 /m 2 /h furthermore additional design calculation studies are required taking into account the presence of organic impurities to calculate the actual design parameters that affect the purification process. impurity impurity in influent impurity in carbon bed effluent impurity in sand medium effluent threshold odor no. color units mn-ppm fe-ppm turbidity-ppm chlorine-ppm 35-140 4-14 0.066-0.15 0.2-0.37 0.45·-1.4 1.4-2.8 0-4# 0-2 0.008-0.017 0.006-0.025 0.07··0.15 0-0.25 35-70# 1-2 0.008-·0.017 0.012-0.087 0.100.25 1.4-2.8 8x30 mesh size 14x40 mesh size total surface area # sq m/g bed density @ lb/cu ft particle density^ g/cu cm effective size mm uniformity coefficient 800-900 30 1.4-1.5 0.80-0.90 1.9  800-900 30 1.4-1.5 0.55-0.6  1.7 mesh size bed depth (contact time) 2.5ft (1gpm/cu ft) 5.0ft (0.5gpm/cu ft) 7.5ft (0.3 gpm/cu ft) abs removal capacitypercent^ 8x30 # 12x40 @ 3.8 5.6 7.6 9.0 10.9 11.5 system factor filtration adsorption adsorption only flow rate-gpm/sq ft bed depth-ft backwash-gpm/sq ft minimum free-boardpercent mesh size 2.5  2.5-5.0 5-15 30 8x30 or 14x40 2.5-5.0 5-10 5-15 30 8x30 or 14x40 design criteria of an activated carbon bed for dechlorination of water 48 ijcpe vol.9 no.4 (2008) nomenclature abs : adsorption beds system b : the efficiency constant for each carbon. b c : the concentration of cl2 in the effluent (ppm) : the breakpoint of 0.01 ppm cl2 and the absence of bacteria or any organic interference were assumed. i c : the concentration of cl2 in the influent (ppm). b c : the concentration of cl2 in the effluent (ppm). d : diameter of the carbon bed (ft). l : length of carbon bed (ft). v : filtration rate ( f tcugpm / ). references 1 bay1is, j.r., “elimination of taste and odor in water”, mcgraw hill, 1935. 2 boby w.m.t & solt g.s, “water treatment data”, hutchinson & co. (1967). 3 degramount g., “water treatment handbook”, volume 1, english edition, (1991). 4 dostal, k., et al.,” carbon bed design criteria study at nitro, w.va.” jour. a ww a, 57: 663 (may 1965). 5 eld, e.f. & flentje, m.e., “quality improvements resulting from industrial needs at hopewell”. jour. awwa, 53:283(mar. 1961). 6 fair, geyer, okun,” elements of water supply and wastewater disposal”, john wiley, (1971). 7 flentje, m., e. & hager, d.g., “advances in taste and odor removal with granular carbon filters”, water & sewage works 3: 76 (1964). 8 flentje, m.e. & hager, d.g.,”re evaluation of granular carbon filters to taste and odor control” .jour. awwa, 56:191(feb.1964). 9 gulp, g.l. & culp r.l. “new concepts in water purification”, van nostrand reinhold, 1974. 10 joyce, r.,” feasibility study of granular activated carbon adsorption for waste water renovation”, publ. no.999wp-12, us public health service,washington d.c. (1964). 11 mantell c.l., “industrial carbon, its elemental, adsorptive, and manufactured forms”, d.van nostrand 1974. 12 magee, v., “the application of granular active carbon for dechlorination of water supplies”, proc. soc. water treatment & examination, 5: 17(1956). 13 robeck, g.g.; dostal, k.a.: & woodward, r.l.,” studies of modifications in water filtration” .jour. awwa, 56:198(feb.1964). 14 robeck, g.g., et.al. , “effectiveness of water treatment processes in pesticide removal”, jour. awwa, 57: 181(feb. 1965). 15 smith, d. & skeel, a., “water filtration in one operation”, water works & wastes eng., 1:46 (1964). 16 weber, w. & morris j.,” kinetics of adsorption of fluidized media”, j. water pollution control federation, 37; 425 (1965). 17 white, “handbook of chlorination”, van nostrand reinhold, 1972. 18who 1984, “guidelines for water quality”, 2nd. edition, vols. 1&2 geneva. 19 water fac., general information on drinking water (2000) water information free water information http://www. pangea.org/unsco. e c http://www/ muna y. abdul – ahad 49 ijcpe vol.9 no.4 (2008) االفكار التصحيحية لعمود الكربون المنشط المستخذم في ازالة الكلور مه الماء الخالصة اٌ . اٌ حثٛثاخ انكشتٌٕ ًٚكٍ اٌ ذسرعًم ذقهٛذٚا نهفهرشج ٔرنك الصانح انًٕاد انعانقح أ كٕاسطح أ اداج نهفهرشج ٔااليرصاص , ايكاَٛح ذٕفش انجٓاص انًُاسة, اخرٛاس انجٓاص انًُاسة نٓزِ انعًهٛح ٚعرًذ عهٗ يذٖ شذج أ انًذٖ الصانح يشكهح انًٕاد انعضٕٚح .ٔكزنك عهٗ انشغثح فٙ يذٖ صٚادج انرحسٍ نضشٔف االيرصاص نهكشتٌٕ انًسرخذو اٌ ْزِ انذساسح قذ ذى اجشاؤْا نحساب انقٛى انرصًًٛٛح الصانح انكهٕس فقط يٍ انًاء تاسرخذاو حثٛثاخ انكشتٌٕ انًُشط انخساسج , انٕقد انز٘ ٚسرغشقّ انسائم تانرًاط يع انكشتٌٕ , دسجح انحايضٛح, اخزٍٚ تُظش االعرثاس ذأثٛشاخ يعذل انجشٚاٌ اخزٍٚ انخٕاص انفٛضٚأٚح تُظش االعرثاس ٔعهٗ , قٛاط اقطاس انحثٛثاخ, يقذاس ذًذد انكشتٌٕ اثُاء عًهٛح انغسم انعكسٗ , تانضغط .فشض عذو ٔجٕد ا٘ تكرشٚا أ ذًاط عضٕ٘ فٙ انًاء انًسرخذو يع حثٛثاخ انكشتٌٕ انًُشط انًسرعًهح available online at https://ijcpe.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.19 no.1 (march 2018) 57 – 60 issn: 1997-4884 corresponding authors: ahmed abdulmueen alher, email: ahmed_mueen@yahoo.com, mohammed saleh aljawad, email: na, abdullah abdulhasan ali, email: na iraqi journal of chemical and petroleum engineering static model of zubair reservoir in luhais oil field ahmed abdulmueen alher, mohammed saleh aljawad a and abdullah abdulhasan ali b a petroleum technology department / university of technology b south oil company / geology studies department abstract static reservoir modeling is the interacting and analysis of the geological data to visualize the reservoir framework by threedimensional model and distribute the static reservoir properties. the petrel e&p software used to incorporate the data. the interpreted log data and core report used in distribution of petrophysical properties of porosity, water saturation and permeability for zubair reservoir in luhais oil field. the reservoir discretized to 274968 cells in increments of 300, 200 and 1 meter in the direction of x, y, and z respectively. the geostatistical approach used in the distribution of the properties of porosity and water saturation overall the reservoir units. the permeability has been calculated with classical method depending on the routine core reports data. the results show the main reservoir unit is 1c where its porosity and permeability are about 20% and 400md respectively. this unit underlaid by barrier unit and rounded by water. the estimated value of oil in place is about 209*10 6 scm 3 , most of it accumulate at 1c unit and the other at the upper parts of unit 1e. keywords: porosity, permeability, water saturation 1introduction static model includes construction of structural and stratigraphic framework, it is also involves property modeling for petrophysical properties by using statistical distribution methods. the geological model build by the geoscientist and then modified with dynamic data to simulate the model by reservoir engineer. the structural and stratigraphic models are to capture the structure elements such as faults and horizon, also allocate the reservoir units. [1] the petrophysical modeling is the using of statistical distribution methods to distribute the petrophysical model for un-drilled reservoir cells, depending on the data obtained from the drilled areas. the geostatistics algorithms is the main and modern method use to populate the petrophysical properties overall the reservoir area [2]. there are many modern computer programs used for the purpose of constructing and visualizing the static model. the widely using software is petrel which provided by schlumberger. petrel is a completed program in oil industry from exploration to production. 2area of study luhais field is one of the iraqi oil fields that produces oil with api gravity of about 32 o . it is located in south of iraq about 100 km north-west of al-basra city and 80 km north of rumaila oil field as shown in fig. 1). it is neighboring from east by ratawy and raji fields, from north suba oil field, from west by oor oil field and from south by boleih structure. zubair formation which is the case of this paper, in general represents one of the main formations that contain hydrocarbon in south of iraq, which is deposited in the lower cretaceous. generally, it consists of sequences sandstone, shale and siltstone layers, also has limestome at lower and upper parts of formation. [3] at luhais oil field, zubair formation divided into three members, which are upper shale member, sand member, and lower shale member. fig. 1. iraqi map show the location of iraqi oil fields a. a. alher, et al. / iraqi journal of chemical and petroleum engineering91,9 (2018) 57-60 85 from log interpretation for zubair formation, the upper shale member contain oil above water oil contact at depth of 2755m below sea water level, and the other two are water bearing. therefore, this study will focus on the upper shale member only. 3structural and stratigraphic models structural modeling is the interpretation of geophysical data to define the depth map for top of the reservoir and define the fault pattern if existed in reservoir structure, then use the results of interpretation to define the reservoir geometry and build three-dimensional framework for the reservoir. [4] the structure of the upper shale member reservoir in zubair formation is not affect by fault, and the depth contour map of top of reservoir gathered from the seismic study for luhais oil field [5]. after digitizing this map, it was imported to petrel as digitizing points and resembled by making surface process in petrel software. the basic aim of stratigraphic model is to allocate the reservoir unit depth and thickness for each well and make a correlation between wells depending on well logs. then these reservoir units are divide vertically into multilayers to get more accuracy in the definition of reservoir properties. from the previous studies and geological well reports, the stratigraphy of the upper shale member of zubair formation in luhais oil field is divide into six units, according to their origins in lithological correlation, which are (1a, 1b, 1c, 1d, 1e and 1f). these units divided to multilayers according to their thickness as given in table 1). table 1. division of vertical direction of 3d grid reservoir unit thickness (m) no .of layers zinc (m) top layer 1a 2.70 3 0.9 1 1b 15.00 10 1.5 4 1c 12.60 18 0.7 14 1d 2.610 3 0.87 32 1e 20.00 20 1.0 35 1f 3.00 3 1 55 4petrophysical modeling petrophysical modeling is the process of distributing the continuous log properties overall the reservoir by using geostatistics concept. geostatistics is “study of phenomena that vary in space and/or time “ [6]. also may be define as a statistic algorithm try to estimate property in space depending on the assumption that the property has a degree of continuity. reservoir engineers use it for the estimation of the properties in area where no well data are available to visualize the reservoir properties. kriging is the main technique of geostatistics and widely used which provided by d. krige at 1950. the other modern techniques represent a modifying of it. [7] sequential gaussian simulation is the modern algorithm that widely used and recommended to use with continues property in reservoir modeling for its simplicity, flexibility and it is reasonably efficient. [6] the porosity and water petrophysical model was build depending on cpi reports for eight wells that gathered from [8]. the first step of petrophysical modeling is the upscaling of well log. it means the definition of the property for each cell crossed by the well. this definition done by calculating the average values of well log entire the cell. in other words, if the cell thickness is 0.9 m and log has value every 0.25 m, which mean there are three log values in the cell, so the cell value is the average of these three values. as shown in fig. 2) at this step of property modeling, the porosity defined for each cell that crossed by well. so to distribute for the reservoir, the geostatistics, which also called spatial distribution, tool used. there are many algorithms of geostatistics provided by petrel. in this study, the sequential gaussian simulation algorithm used for distribution of porosity. fig. 2. scaled up porosity the permeability property estimated with classical method by make relation between porosity and permeability core data. the report that used were four reports from different wells (lu 03, lu 05, lu 07 and lu 08). the data scattered for unit 1c separately from the other units because the unit 1c is the main reservoir unit. from the scatter plots as shown in fig. 3), and fig. 4) the exponential relationships get from eq.error! reference source not found. and eq. error! reference source not found., were obtained with correlation coefficient (r 2 ) of 0.754 and 0.753 for 1c and the other units respectively. (1) (2) where, k : permeability : porosity a. a. alher, et al. / iraqi journal of chemical and petroleum engineering91,9 (2018) 57-60 85 5volumes calculations a great portion of the world’s oil reserves is contained in reservoirs, which play an important role in oil exploration and makes a large contribution toward oil production worldwide. however, characterization of case study reservoir is very complex as compared to conventional reservoirs. [9] fig. 3. scatter plot between core permeability and porosity for 1c unit fig. 4. scatter plot between core permeability and porosity for all reservoir unit except the 1c unit volume calculation means the estimation of pore volume and the stuck tank original oil in place (stooip). the general equation for the estimation of pore volume for each grid cell is multiplying the cell volume (bulk volume) by the porosity. the total (stooip) is the sum of stooip in reservoir grid cells. from the equation eq. (3) the stooip calculated. (3) where, v (b ) : bulk volume (cell volume) : porosity s_w : water saturation b_o : oil formation volume factor calculation with a static model depend on cell value of porosity and water saturation of the petrophysical model that estimated from well logs and distribute overall the reservoir with geostatistics methods. the used one value of 1.25 bbl/stb. 6results and discussion the structural contour map of the top of reservoir is shown in fig. 5). it shows there are many domes found in the reservoir and the reservoir does not affect by fault. the reservoir visualize with framework of 13426.3, 20910.7, and 50 meters in x, y and z direction. this framework divided the reservoir into 274968 grid cells with increment of 200, 300, 1 meters of x, y, and z direction. the porosity distribution model shows that the unit 1c and 1e units have good porosity of 0.2 and 0.16. the other units show low porosity values. as shown in fig. 6), the porosity distribution model horizontally for top of unit 1c and vertically by well section through the wells lu 45, lu 43, lu 11, lu 05, lu 08, lu 23, and lu 27. the fig. 6, c) shows the histogram of porosity data of well log, scale up porosity and porosity model. the water saturation model as shown in fig. 7), the 1c unit is oil zone and the water rounded it from the sides. the almost thickness of the 1e unit is water earing except the upper parts of it that above water oil contact 2755m. fig. 5. depth contour map of top of reservoir a. a. alher, et al. / iraqi journal of chemical and petroleum engineering91,9 (2018) 57-60 06 the permeability model shows the units 1a and 1b have very low permeability, this accepted with cpi data that shows these units have a lithology of shale, these two units represent the cap rock of the reservoir. the unit 1c has a good permeability with averaging of 400 md. the unit 1d shows low permeability, so it is a barrier unit between 1c and 1e units, where 1e unit has average permeability of 200 md. the oil in place calculated by the volumetric method and estimated value was 209 million of standard cubic meter. fig. 6. porosity distribution fig. 7. water saturation distribution 7conclusions  zubair formation in luhais oil field provides a second main reservoir with nahr umar formation. the structure of upper shale member reservoir is very complicated because of the sequences of lithology between shale and sand.  the main unit in upper shale member reservoir is 1c unit which characteristic with high porosity and permeability  the oil in place of the zubair formation in luhais oil field is about 209 millions of standard cubic meters. acknowledgment university of technology / petroleum technology department ministry of oil / reservoir & fields development directorate south oil company / field division nomenclatures v_(b ) : bulk volume (cell volume) : porosity s_w : water saturation b_o : oil formation volume factor k : permeability references [1] i. m. darhim m. noureldien, "static model qc: technical aspects and practice from a to z," in spe north africa technical conference, cairo, egypt, 2015, id : spe-175825-ms . [2] p. r. a. m. bentley, "reservoir model design", a practitioner’s guide, springer, 2015 . [3] south oil company, "geological model for upper shale member reservoir in luhais oil field", unpublished study, 2014 . [4] l. cosentino, integrated reservoir studies, tecnip ed., france: institut francais du petrole publication, 2001. [5] iraqi exploration oil company, "siesmic and geophysics study for suba and luhais oil fields," 2014 . [6] v. deutsch and m. j. pyrcz, geostatistical reservoir modeling, new york: oxford university press, 2014 . [7] j. r. fanchi, "integrated reservoir asset management", book, gpp, 2010 . [8] m. s. al-jawad, a. a. ali and a. a. alher, comprehensive study of zubair reservoir in luhais oil field, thesis: university of technology, iraq, 2017 . [9] m. s. al-jawad and k. a. kareem, "geological model of khasib reservoir-central area/east baghdad field," iraqi jornal of chemical and petroleum engineering, vol. 17, no. 1997-4884, 2016. ijcpe vol.9 no.1 (march 2008) 45 iraqi journal of chemical and petroleum engineering vol.9 no.1 (march 2008) 45-49 issn: 1997-4884 studying the effect of h2so4/h2o ratio on the properties of positive electrode in lead-acid battery muslet s. hussain* and sundos a.k. jabbar * chemical engineering department college of engineering university of baghdad – iraq abstract the lead-acid battery has become so dependable in its used applications of automobile starting, emergency lighting and telecommunications, which left an impression that no further investigation is necessary or desirable. while there has been slow continuous improvements in lead-acid battery performance and mainly limited to design and material engineering. this work is mainly devoted to the properties of the active mass of the positive electrode and the acid/water ratio during the manufacturing process. a field study is carried out at the state battery manufacturing company located in baghdad, to prepare batches of lead mono-oxide with predefined quantities of liquid additives (i.e. sulfuric acid and water). quality control and laboratory routine analysis using x-ray diffraction, porosimeter and bet techniques, as well as density, penetration tests of residual lead content ware conducted during the batch process. after the assembling of the positive plates produced during this research into the final product, final testing including electrical capacity and dry charging were performed. it was concluded from the results obtained, that the effective h2so4/h2o ratio and hence h2so4/pbo ration and paste density with α/β-pbo2, are the limiting factors of the electrical capacity and durability of the batteries concerned. keywords: lead-acid battery, positive electrode. introduction the manufacture of secondary batteries based on aqueous electrolyte forms a major part of the electrochemical industry. by far the largest total capacity produced is that of lead-acid batteries whose dominance is due to a combination of low cost, versatility and the excellent reversibility of the electrochemical system. the lead-acid batteries have extensive use both as portable power sources for vehicle service and traction, and in stationary applications ranging from small emergency supplies to load leveling systems [1]. a typical lead-acid battery consisted of three active elements, namely; positive plate, negative plate and diluted sulfuric acid. in state battery manufacturing company (s.b.m.c.) many types of lead-acid battery are produced, but all of these are classified as starting, university of baghdad college of engineering iraqi journal of chemical and petroleum engineering studying the effect of h2so4/h2o ratio on the properties of positive electrode in lead-acid battery ijcpe vol.9 no.1 (march 2008) 46 lighting & ignition (sli) batteries (which is a battery of usually 12 volts or 24 volts used for starting, lighting and ignition in vehicles with internal combustion engines). in sli battery, the dominant element in design calculations and material balance is the positive plate [2,3]. so, the improvements in positive plate characteristics will lead to increase in the battery efficiency and life. the positive plates are prepared by progressive production stages. but, it is reported that the mixing process defines the major characteristics of the final battery. the principles of mixing process is to provide a porous mass with sufficient porosity to give the coefficient of requirement performance for the formed active mass and adequate rigidity and cohesion to withstand vibration in service, as well as the dimensional changes involved in each discharge-charge cycle, for the specified life time of battery. water is used as pore-forming agent and sulfuric acid is added to provide the basic sulfates, which cause the necessary cementation [3]. the main parameters related to paste mixing process are listed as follows:  temperature of mixing process.  h2o/pbo ratio.  h2so4/pbo ratio.  ph the electrical capacity of positive plate is controlled by the inner and outer parameters [7], which are listed in table 1. table 1, the inner and outer parameters controlling the electrical capacity of positive plate inner parameters outer parameters  chemical composition  crystal morphology  porosity  pore distribution  inner surface area  conductivity  impedance  inhibitors  double layer adsorption  current density  temperature  acid concentration  plate thickness it was reported that [3,6,7]:  in general, the effects of inner parameters are higher than the outer parameters.  above parameters are dependent of one another, and should be considered together.  regarding the ratio α-pbo2/β-pbo2, it has been found that the best ratio is equals to 0.8 for the purpose of sli batteries [8]. the aim of the research is to determine relationships between h2so4/pbo ratio and paste density with α/βpbo2 ratio. so, controlling the electric capacity and life time of battery by varying these parameters experimental work the positive plates of sli lead-acid batteries are manufactured according to a time-honored industrial process in which a mixture of finely divided lead, lead oxide, basic lead sulfates, water and sulfuric acid is pressed, in the form of a paste, into a grid of a lead alloy. the pasted grids are held in an environment of controlled humidity and temperature for re-crystallization process. the plates are then electrochemically formed in a dilute sulfuric acid electrolyte to convert the active material to pbo2. the forming process involves a complicated sequence of reactions, and it is necessary to carry out the formation in two stages separated by a hold time in order for most of the active mass to be converted. the details of manufacturing process may vary from one manufacturer to another, but the whole operation, which is performed on batches of plates, usually takes about a one week. in the present study, eight experiments were conducted in babil-1 factory\s.b.m.c. for producing positive plates of different mixture ingredients. each one carried out according to the outlines illustrated in fig. 1. fig. 1 lists the experimental data for the eight conducted experiments muslet s. hussain and sundos a.k. jabbar ijcpe vol.9 no.1 (march 2008) 47 table 2 the experimental data of present work for 1000 kg lead oxide, 0.4 kg fiber additives, 6 lit/min acid and 10 lit/ min water additive rate run no. sulfuric acid, liter deionized water, liter h2so4/pbo, wt. ratio paste density, g/cm 3 1 61.0 140 8.5 4.10 2 76.0 140 10.6 4.10 3 82.0 140 11.5 4.10 4 86.0 140 12.0 4.10 5 96.5 140 13.5 4.10 6 82.0 135 11.5 3.85 7 82.0 160 11.5 4.10 8 82.0 175 11.5 4.50 analysis and testing chemical tests the chemical tests were conducted according to the testing standards of chloride technical limited. lead monoxide content lead dioxide content physical tests pam apparent density determination this test was conducted using mercury porosirneter of ruska brand, the apparent density (da) was calculated as follows: volume mat erial act ive weightmat erial act ive     gl gl a vv ww d (1) where: wl is weight of the sample, wg is weight of the grid, vl is volume of the sample, vg is volume of the grid. paste density test t1is carried it using a special cup supplied with the paste mixer by the manufacturer to determine the paste density [7]. surface area measurement (bet test) the internal surface area for the samples of pam was determined using bet method. the testing apparatus is asap 2400, brand; micromeritics instrument. this method is based on the measuring of nitrogen gas adsorbed as result of pressure decrease due to adsorption of a dose of known volume of the gas. x-ray diffraction test (xrd) the xrd tests were conducted using a diffractometer of siemens brand, model; srs d-500, its specifications are; tube; cu, voltage; 40 kv, current; 20 ma, wave length; 1.5050 a°, 22θθθθθθ 0 range is 20° to-60°. scanning electronic microscopy investigations a canibride brand sem instrument, type; stereoscan 240, magnification; 100,000 was used for examining samples of cured and formed pastes before starting this test. electrical tests for each experimental run, two batteries were assembled using positive plates made from the obtained paste. these batteries were tested according to the international electrochemical commission standard (iec95) to examine the electrical specifications [9]. two tests were conducted, namely; electrical capacity test and dry charging test. results and discussion effect of h2so4/pbo ratio on α/β-pbo ratio the formed plates contain both the acidic β and alkaline α polymorphs of pbo2. the capacity and life of battery is determined by the ratio of a βpbo2. the relationship between the ratios α/β-pbo2 and h2s04/pbo is illustrated in fig. 2, which demonstrates that a decrease in h2s04/pbo ratio involves an increase in α/β-pbo2 ratio. this behavior is existed because in high sulfatized paste (of 12 to 13 h2s04/pbo ratios) the paste maintains a low ph value on the reaction layer during the formation process, which leads to the dissolution precipitation-mechanism and forming a large amount of β-pbo2. h 2 so 4 /pbo ratio (wt %) 8 9 10 11 12 13 14   -p b o 2 r a ti o 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 fig. 2 the relation between h2s04/pbo and α/β-pbo2 ratio studying the effect of h2so4/h2o ratio on the properties of positive electrode in lead-acid battery ijcpe vol.9 no.1 (march 2008) 48 effect of h2o/ h2so4 ratio on the paste density the increase of pam density decreases the movements of electrolyte sulfate ions during formation process and maintains the interior of the plate alkaline for a longer time. so, the α-pbo2 polymorph will be of high content resulting in the increasing of α/βpbo2 ratio, as shown in fig. 3. apparent density (g/cm 3 ) 3.8 3.9 4.0 4.1 4.2 4.3 4.4 4.5 4.6   -p b o 2 r a ti o 0.75 0.80 0.85 0.90 0.95 1.00 1.05 1.10 1.15 fig. 3, the relation between α/β-pbo2 ratio and apparent density effect of h2s04/pbo ratio on the internal surface area of pam (bet) the internal surface area increases with increasing h2s04/pbo ratio and that is because the increasing in h2s04/pbo ratio will produce a rise in the value of specific pore volume leading to increase the number of pores occupying the same pore volume and that results in a high surface area. as shown in fig. 4. h 2 so 4 /pbo ratio (wt %) 8 9 10 11 12 13 14 in te rn a l s u rf a c e a re a ( m 2 /g ) 2 3 4 5 6 7 8 9 =4.1 (g/cm 3 ) =3.85 (g/cm 3 ) =4.5 (g/cm 3 ) best fit for =4.1 (g/cm 3 ) fig. 4, effect of h2s04/pbo ratio and density on the internal surface area also, fig. 4 demonstrates that the apparent density of pam exerts au exceptionally strong influence on the internal surface area. effect of h2so4/pbo ratio on the electric capacity the electric capacity is characterized by all discussed parameters. the structure of pam considers as a limiting factor for the obtained capacity and it is controlled through the varying of specific pores volume and in a smaller degree by internal surface area. the first parameter determines the fluxes of ions taking part in the reaction, while the latter parameter indicates the surface area that the electrochemical reaction can take places upon it. fig. 5 shows that an increase of the h2s04/pbo ratio will lead to increase of the battery electric capacity. h 2 so 4 /pbo ratio (wt %) 8 9 10 11 12 13 14 c /c 2 0 0.70 0.75 0.80 0.85 0.90 0.95 1.00 = 4.1 g/cm 3 = 3.85 g/cm 3 best fit for = 4.1 g/cm 3 fig. 5, effect of h2s04/pbo ratio on electric capacity conclusions from the present work, the following conclusions can be obtained: 1. the effect of decreasing apparent density of pam exerts a strong increasing of the internal surface area and accordingly increasing the obtained electric capacity of the complete battery. 2. the adding rate of water and sulfuric acid are important parameters during the mixing process of positive paste since they are controlling the working temperature and paste density. 3. it was found that the best ratio of cx/13-pb02 for sli battery (which is equal to 0.8 f83 can be almost obtained by using the following mixing parameters: • h2so4/pbo = 11.5 % • ρ= 3.85 g/cm 3 these values give α/β-pbo2 = 0.79 (from xrd analysis). muslet s. hussain and sundos a.k. jabbar ijcpe vol.9 no.1 (march 2008) 49 acknowledgment we would like to express our sincere thanks to the staff of al-basil general co., for the financial grant made available to accomplish this research work, also for their assistance during the work. we are thankful also to the staff of al-raya co. for their help and cooperation during the present work. references 1. krystek, lee, “the baghdad battery and ancient electricity”, the battery man, vol42, no.1, pp.44-46, 2000. 2. vincent, cohn a., modern batteries, edward arnold, england, 1982. 3. internet web site; www.accuoerlikon.com qerlikon batteries company, download date: 1-3-2002. 4. internet web site; www.toub.com/doeelecsience/index.htm, discharge and charging of lead-acid battery, download date: 5-3-2002. 5. vinal, george wood, storage batteries, 4th edition, john wiley & sons inc., england, 1955. 6. bode, hans, lead-acid batteries, john wiley & sons inc., usa, 1977. 7. holden, l. s., “a guide to lead-acid battery making”, chloride technical ltd., england, 1980. 8. s. rand, david a. j., “research progress into leadacid battery technology, part ii”, the battery man, no.10, pp 12-18, 1987. 9. “standard methods of testing”, a technical document, chloride overseas ltd., england, 1980. http://www.toub.com/doeelecsience/index.htm dr najat _mag_.doc ijcpe vol.8 no.4 (december 2007) 53 iraqi journal of chemical and petroleum engineering vol.8 no.4 (december 2007) 53-58 issn: 1997 -4884 the effect of photo -initiated oxidation on mechanical properties of high density polyethylene / linear low density polyethylene blends najat j. saleh and nabeela a. mohammed chemical engineering department university of technology iraq abstract the long – term behaviour of polyethylene products used out doors is affected by weathering. in the present work, weathering test was carried out to find the effect of the environment conditions on the mechanical properties of hdpe/lldpe blends with different weight percents (0, 15, 30, and 45 %) relative to the lldpe by increasing the exposure times to (100, 150, 200, 250, 300) hr. a series of tests (destructive), tensile, impact and hardness were carried out on the prepared samples, the results obtained declare the changes on the material behaviour from ductile to brittle and the polymer sh ows a decline in the mechanical properties with increasing the exposure times. in the present work empirical equations were reached which could be used to calculate one of the mechanical properties in terms of exposure time, weight percent of lldpe content and to other mechanical properties. keywords: low density polyethylene, how density polyethylene. introduction the term "weathering" is used by technologists as a comprehensive description of all the possible changes which may occur in polymer on exposure out doors. the main components of the weather which causes degradation are sunlight, temperature, moisture, wind, dust and pollutants. moisture and humidity can have secondary effects in weathering, the primary process occurring is photo – oxidation or perhaps more accurately photo initiated oxidation; the effect of light is primarily on the generation of free radicals [1]. the sun is the primary cause of most climatic phenomena found on earth. the wave length of the radiation from the sun which reaches the earth's surface extends from the infra – red (> 700 nm), through the visible spectrum (400-700 nm) into the ultra – violet ( < 400 nm) with a cut off at approximately 300 nm depending upon atmospheric conditions. the energies of 700, 400 and 300 nm photons are approximately 170, 300 and 390 kj mol –1 respectively. the strength of c – c and c – h bonds are approximately 240 and 340 kj mol – 1 respectively although they may be very much less in certain environments [2]. polymers have different photodegradation sensitivities to uv light of different wave length. as plastics of increasing durability have been made available, it has become more necessary and at the same time more difficult to predict acceptable service life of specific formulations and products without waiting for actual in use failures to occur. many polymers show a decline in mechanical properties during service life time (e.g. loss of tensile strength, surface appearance or discoloration) when they are exposed to sunlight and particularly to uv – light .thus, stabilization of polymers is of great economic importance, the aim of stabilization is to prevent and / or control the processes, which may damage a polymer during its preparation, compounding, processing, or use [3]. organic materials, both of synthetic and natural origin, readily undergo reaction with oxygen [4]. oxidation can manifest itself in every stage of the life cycle of a polymer, during manufacturing and storage of university of baghdad college of engineering iraqi journal of chemical and petroleum engineering the effect of photo-initiated oxidation on mechanical properties of high density polyethylene/low density polyethylene blends ijcpe vol.8 no.4 (december 2007) 54 the polymer resin, as well as during processing and end – use of the plastic article [5]. thus, photo oxidation degradation of polymers has received considerable interest. in (1967) blumberg studied the change in mechanical properties of polyethylene, high impact polystyrene, polypropylene and polymethacrylate, based on tensile mechanism, after exposure to artificial weathering [6]. as regards the effect of pollutants on organic polymers, jellinek (1978) has shown that polyethylene and polypropylene are cross – linked when exposed to ultra violet radiation in the presence of oxygen and sulphur dioxide [7]. in (1981) pabiot jose studied the change in mechanical behaviour of high density polyethylene, polypropylene and polyvinyl chloride during photochemical aging in which the polymers were exposed for 1700 hours to artificial aging in weatherometer [8]. in (1995)hokstra, breen and audouin studied the uv – stabilized and non uv – stabilized hdpe foils that were photo – oxidized in a xenotester[9].in (1997) hoekstra and spoormaker studied the mechanical behaviour of non uv – stabilized and stabilized hdpe foils as a function of the exposure time and at different straining rates[10].in (2003) shishan, and jun , studied the structure properties of high – density polyethylene functionalized by ultraviolet irradiation at different light intensities in air[11]. in this study, the change in mechanical properties of blends of linear low density polyethylene, lldpe,with high density polyethylene hdpe,after exposure to uv light ,are investigated. experimental work materials in this work two types of commercial polyethylene were used, one was the high density polyethylene (ehm 6003) of a density equal to 0.963 gm/cm3 that was used as a matrix and the other was linear-low-density polyethylene of density equal to 0.94 gm/ cm3. methods the process involves mixing of high-density polyethylene with different weight percent (0, 15, 30, and 45%) of linear-low-density polyethylene using the two roll mills. the mixing machine used for this purpose a roll mill poly mix 150p the mixing machine is operated at a temperature of 135 oc and at speed approximately 10 mm/min. standard test of all mechanical and environmental properties of the prepared polyethylene blends were carried out. a climatest weather – o – meter type (erichsen) was used to age the samples. the light source of a climatest consists of a cylindrical geometric array of fluorescent tubes, which are arranged in the center of the test chamber and emit radiation similar to that of natural sunlight. condensation was produced by exposing the test surface to a heated saturated mixture of air and water vapour. specimens were mounted on a frame which rotates at 1 rev. / min around the lamp system and the specimens were alternately exposed to ultraviolet radiation and condensation. the tests were done on sets of the hdpe / lldpe blends with different weight percents (0, 15, 30, and 45) % relative to the lldpe by exposing the sets of the four types for 300 hours in climatest with 50 % relative humidity and temperature of 40oc, and samples were collected every 50 hours. tensile properties, impact resistance and hard ness tests were carried out for examining the mechanical properties of exposed and unexposed samples. tensile properties were measured by using instron testing machine. data on toughness are usually supplied from izod or charpy impact test, in this work the impact resistance was determined using charpy impact test instrument no – 43 – 1, made by testing machines, inc., samples were notched (1 mm depth ) by using ceast notch instrument. brinell method was used to determine the hardness of the polymer materia ls, a rigid steel ball was used in brinell test with (5 mm) diameter, and (700n) load was applied at the sample for (15 sec). results and discussion tensile test the modulus measures the resistance of a material to elastic deformation. fig.1 shows the modulus of elasticity (e) of the materials as a function of exposure time and at different % lldpe content. from this figure it is clearly seen, that the increasing of the exposure time from (100) hrs to (300) hrs causes an increase in the modulus of elasticity, this may be due to the fact that increasing the exposing time causes an increase in the chain scission and cross linking due to photo – oxidation degradation. fig.1 modulus of elasticity as a function of exposure times at different lldpe content (wt %). t i m e ( h r ) m od u lu s of e la st ic it y( m p a) 2 0 0 2 6 0 3 2 0 3 8 0 4 4 0 5 0 0 5 6 0 5 0 0 5 0 1 0 0 1 5 0 2 0 0 2 5 0 3 0 0 3 5 0 %lldpe=0 %lldpe=15 %lldpe=30 %lldpe=45 najat j. saleh and nabeela a. mohammed ijcpe vol.8 no.4 (december 2007) 55 the tensile strength (σu) values (the stress at maximum load) were determined; fig.2 shows the tensile strength as a function of exposing time and at different % lldpe contents. it is clear that increasing the exposure time from (100) hrs to (300) hrs leads to decrease the tensile strength, that the polymer shows a decline in mechanical properties when it is exposed to uv – light. due to chemical reactions, initiated by a u – v quantum and in the presence of oxygen, the long polymer chains can break. if many chains are broken, the polymer is unable to transfer a load effectively and as a result the polymer embrittles. fig. 2 tensile strength as a function of exposure times at different lldpe content (wt %) figure (3) shows the tensile strength at break(σb) as a function of exposure time and at different % lldpe contents, from this figure it is clear that the (σb) for the neat polymer (hdpe) decreases with increasing exposure time. samples contained (15, 30 % )of lldpe were broken as a ductile materials during exposing to ultra violet radiation at exposure time ranging between (0 – 100) hr and for time ranging between (0 – 150) hr for the samples containing 45% lldpe, that when the load in the tensile test reached a certain level the crack of the specimen propagated in a controlled manner under a gradually increasing total load and opens into a u – notch owing to withdrawing (high plastic extension) of the remainder of the material . therefore from this figure it is clearly seen that the tensile strength of these blends decrease with increasing exposure time limit of the previous intervals. the ductile – brittle behavior transition can be seen in blends which contain (15, 30%) lldpe at (200) hr and at (250) hr for the blends with 45% lldpe. the samples failed as a brittle material at a stress which was equal to the values of tensile strength, and gradually decreased with increasing the exposure time to (300) hr, this is due to the photo – oxidation degradation which causes a breakdown of the bonds in the polymer chain and cross linking and that leads to decrease the molecular weight and increase the crystallinity, this is the direct cause of mechanical failure. fig. 3 tensile strength at break as a function of exp osure times at different lldpe content (wt %) elongation is the increase in length of a measured polymer strip, when stretched to the breaking point. it is expressed in terms of the percentage of the original length. fig.4 shows the % elongation at break as a function of exposure time and at different % lldpe contents, from this figure it is clear that increasing the exposure time leads to decrease the (ζb) which is attributed to the fact that the polymers show a decline in mechanical properties when they are exposed to uv – light, the crystallinity increases and the material loses its elasticity. fig.4 % elongation as a function of exposure times at different lldpe contents (wt %). impact test in view of the surface nature of many weathering processes the degree to which impact properties are affected by exposure to light can be of major importance, fig.5 shows the impact strength (i) as a function of exposure time and at different % lldpe contents. it is clear from this figure that the impact strength decreases with increasing the exposure time, this due to the chain scission and cross linkage which occur during exposing t i m e ( h r ) t en si le s tr en gt h (m p a) 5 0 5 4 5 8 6 2 6 6 7 0 5 0 0 5 0 1 0 0 1 5 0 2 0 0 2 5 0 3 0 0 3 5 0 %lldpe=0 % l l d p e = 1 5 % l l d p e = 3 0 % l l d p e = 4 5 time(hr) t en si le s tr en gt h a t b re ak (m p a) 3 0 3 5 4 0 4 5 5 0 5 5 6 0 6 5 7 0 -50 0 5 0 1 0 0 1 5 0 2 0 0 2 5 0 3 0 0 3 5 0 %lldpe=0 %lldpe=15 %lldpe=30 %lldpe=45 t i m e ( h r ) % e lo ng at io n at b re ak 2 0 0 0 2 0 0 4 0 0 6 0 0 8 0 0 1 0 0 0 1 2 0 0 1 4 0 0 5 0 0 5 0 1 0 0 1 5 0 2 0 0 2 5 0 3 0 0 3 5 0 %lldpe=0 % l l d p e = 1 5 % l l d p e = 3 0 % l l d p e = 4 5 the effect of photo-initiated oxidation on mechanical properties of high density polyethylene/low density polyethylene blends ijcpe vol.8 no.4 (december 2007) 56 the material to ultra violet radiation, which causes an increase in the crystallinity of the polymer, crystallinity influences its stiffenness and toughness, as the crystallinity increases, its flexibility decreases and the polymer’s ability to absorb and dissipate energy also decreases [12]. fig.5 impact strength as a function of exposure times at different lldpe contents (wt %) hardness hardness is commonly defined as the resistance of a material to indentation by a harder material with applied load. fig.6 shows the brinell hardness (hb) as a function of exposure time and at different % lldpe contents. from this figure it is clearly seen that the increase in exposure time leads to an increase in the hardness of the material, this may be attributed to the fact that a strong change in morphology affects the mechanical behaviour of weathered poly mers negatively, the molecular weight decreases and the density and crystallinity increases, increasing the crystallinity increases hardness, stiffness, heat resistance, modulus of elasticity and chemical resistance [13, 14]. fig.6 brinell h ardness as a function of exposure times at different lldpe contents (wt %). the analysis of empirical correlation the experimental results of this study are used to develop empirical correlation. the dependent and independent variables were introduced in to the computer program in such a way that the developed models could be used for the weathered hdpe / lldpe blends to find the change in mechanical properties caused by exposing the material to ultra violet radiation. the independent variables, which affe ct the mechanical properties of the weathered hdpe / lldpe blends, are weight percent of lldpe content and the exposure time. equations (3.1) to (3.5) as shown in table 1 represent the developed models for the modulus of elasticity, tensile strength, tensile strength at break, brinell hardness and impact strength with weight percent of lldpe content and exposure time respectively, the appropriate coefficient is used from table 2. equation (3.2) has less absolute average error (0.5%).equation (3.6) as shown in table 3 represents the relation between modulus of elasticity and the combination (exposure time, weight percent of lldpe, tensile strength, tensile strength at break, elongation at break, brinell hardness, impact strength). absolute error is equal to (0.79).equations (3.6) to (3.10) can be used to calculate one of the mechanical properties depending on the other properties. these equations are in agreement with experimental results. equation (3.10) has less absolute average error (0.36%) that appropriate coefficient is used from table 4, a correlation between the experimental and calculated results for equation (3.10) is given in fig.7. statistical analysis for the developed modules is given in tables (1, 3) which include the values of correlation coefficients which indicate that the experimental and model data are in excellent agreement. table 1. equations of the mechanical properties as a function of exposure time and weight percent of lldpe t i m e ( h r ) im pa ct s tr en gt h( j/ m m 2) 0 . 0 1 6 0 . 0 1 8 0 . 0 2 0 0 . 0 2 2 0 . 0 2 4 0 . 0 2 6 0 . 0 2 8 0 . 0 3 0 0 . 0 3 2 0 . 0 3 4 5 0 0 5 0 1 0 0 1 5 0 2 0 0 2 5 0 3 0 0 3 5 0 %lldpe=0 %lldpe=15 %lldpe=30 %lldpe=45 t i m e ( h r ) b ri n el l h ar d n es s( m p a) 2 . 2 2 . 6 3 . 0 3 . 4 3 . 8 4 . 2 4 . 6 5 . 0 5 0 0 5 0 1 0 0 1 5 0 2 0 0 2 5 0 3 0 0 3 5 0 %lldpe=0 % l l d p e = 1 5 % l l d p e = 3 0 % l l d p e = 4 5 najat j. saleh and nabeela a. mohammed ijcpe vol.8 no.4 (december 2007) 57 table 2. coefficient for the equations (3.1) to (3.5) table 3. shows the relationship between individual mechanical property as a function of other properties and with exposure time and %wt lldpe table 4. coefficient for the equations (3.6) to (3.10) fig. 7 experimental vers us predicted values for eq. (3.10) conclusions results obtained in this work proves that higher exposure times yield higher modulus of elasticity, while increased the exposure times was found to decrease the elongation of the polymeric matrix. addition of lldpe to hdpe matrix reduces the tensile strength at break and the higher exposure times (>150hr) the reductions are less pronounced and it seems to be less for a given blend. increasing exposure times decreases tensile strength, and the higher exposure times seem to reduce the impact strength for all the samples. hardness values were observed to be the highest in pure hdpe, and these values decrease with increasing lldpe wt% blend. moreover, higher exposure times yielded increase in hardness values. in the analysis of empirical correlation of the polynomial equations for modulus of elasticity, tensile strength, tensile strength at break, hardness and impact strength, especially of the high values of the correlation coefficients indicate that the experimental and model data are in excellent agreement. references 1. davis, a., sims, d., "weathering of polymers", applied science publishers, new york, 1983. 2. grassie, n., and scott, g., "polymer degradation and stabilization", cambridge university, cambridge, 1985. 3. hawkins, w.l., "polymer stabilization", wiley, new york, 1972. 4. lutz, j.t., "thermoplastic polymer additives", marcel dekker, new york, 1989. 5. zweifel, h., "stabilization of polymeric material", heidelberg, 1997. 6. blumberg, f.h., "j. appl. polym. sci.", 4, 175, 1967. 7. jellink, h.h., "aspects of degradation and stabilization of polymers", elsevier publishing, amsterdam, 1978. predicted values e xp er im en ta l v al u es 0 . 0 1 6 0 . 0 1 8 0 . 0 2 0 0 . 0 2 2 0 . 0 2 4 0 . 0 2 6 0 . 0 2 8 0 . 0 3 0 0 . 0 3 2 0 . 0 3 4 0 . 0 1 6 0 . 0 1 8 0 . 0 2 0 0 . 0 2 2 0 . 0 2 4 0 . 0 2 6 0 . 0 2 8 0 . 0 3 0 0 . 0 3 2 0 . 0 3 4 p o i n t n o . = 2 4 a v e % = 0 . 3 6 c o r r . c o e . = 0 . 9 9 9 the effect of photo-initiated oxidation on mechanical properties of high density polyethylene/low density polyethylene blends ijcpe vol.8 no.4 (december 2007) 58 8. jose, p., "j. polymer eng. sci", 12, 32 – 38, 1981. 9. hoekstra, h.d., breen, j., and audouin, "uv – exposure on stabilized and non – stabilized hdpe foils", 251 – 262, 1995. 10. hoekstra, h.d., and spoormaker, j.l., "mechanical properties of stabilized and non-stabilized hdpe versus exposure time", dieangew and makromol kular chemie 247, 91 – 110, 1997. 11. shishan, w.u., and jun z., "polym. international", 52, 350 – 355, 2003. 12. colin li pi shan, "approaches to tailoring the structure and properties of polyethylene", ph.d. thesis, university of watcrloo, canada, 2002. 13. crum, n.g.mc, buckleg, c.p., and bucknall, c.b., "principle of polymer engineering", john wiley and sons, 2nd ed., new york, 1997. 14. koerner, r.m., "design with geosynthetics", prentice hall, 2nd ed., new york, 1990. ijcpe vol.10 no.3 (september 2009) iraqi journal of chemical and petroleum engineering vol.10 no.3 (september 2007) 19-23 issn: 1997-4884 risk assessment due to population exposure to lead particles emitted from domestic electrical generators nabeel hashim ameen, mohannad kh. mohammad and takrid m. nafae ministry of science and technology – hazardous materials and environmental researches directorate abstract portable and stationary electrical generators became quite popular in iraq soon after the shortage in national electrical energy after 2003. multi step risk assessment process is used in this study in the assessment of risks caused by contamination of indoor air by lead particles emitted from domestic electrical generators. two portable electrical generators are tested under controlled indoor conditions (radial lg (0.9 kev) fueled with benzene and oil and tigmax (3 kev), fueled with benzene only). lead particles in air were sampled by using portable dust sampler (sniffer, l -30). the atmospheric particulate sampling process is carried out in a flat located in the first floor of a three stories building located in baghdad city, al-zafarania region. the lead concentration in the digested filter papers is measured by using atomic absorption spectrophotometer (buck, usa). dose-to-risk conversion factor is applied in this study to estimate the potential cancer risk to baghdad’s population related to continuous inhalation of airborne lead at the mean observed concentrations. the results of toxicity analysis indicate that public exposure to a irborne lead at the mean observed concentration of 4.991  g/m3 can increase the risk of cancer at a rate of 12 extra cancer cases in a group of million exposed individuals. males are found to be at greater risk than females because of higher inhalation rates. children are found to be the most sensitive group due to low body weight (about 101 expected additional cancer cases in a group of million exposed child). keywords: lead, electrical generators . introduction lead is the most abundant of the heavy metals in the earth’s crust. it has been used since prehistoric times, and has become widely distributed and mobilized in the environment. exposure to and uptake of this nonessential element have consequently increased. both occupational and environmental exposures to lead remain a serious problem in many developing and industrializing countries, as well as in some developed countries. in most developed countries, however, introduction of lead into the human environment has decreased in recent years, largely due to public health campaigns and a decline in its commercial usage, particularly in petrol. acute lead poisoning has become rare in such countries, but chronic exposure to low levels of the metal is still a public health issue, especially among some minorities and socioeconomically disadvantaged groups. in developing countries, awareness of the public health impact of exposure to lead is growing but relatively few of these countries have introduced policies and regulations for significantly combating the problem [1]. most lead emissions in the past have been from motor vehicles burning gasoline containing the antiknock additive, tetraethyl lead (c2h5)4pb. lead is emitted to the atmosphere primarily in the form of inorganic particulates. much of this is removed from the atmosphere by settling in the immediate vicinity of the source. airborne lead may affect human populations by university of baghdad college of engineering iraqi journal of chemical and petroleum engineering risk assessment due to population exposure to lead particles emitted from domestic electrical generators 20 ijcpe vol.10 no.3 (september 2009) direct inhalation, in which case people living nearest to highways are of greatest risk, or it can ingested after the lead is deposited onto food stuffs. most of human exposure to airborne lead is the result of inhalation [2]. the aims of this study are: (1) estimation of the health risk to individuals in baghdad’s population as a result of inhalation of airborne lead emitted from domestic electrical generators. the associations between lead inhalation and the development of adverse health effects to the exposed individuals in baghdad population are evaluated in this study by using linear, no threshold dose-response model. (2) investigation of the effect of the age, sex and activity level of the exposed individuals on the dose delivered and associated risk. experimental work particulates in air are most commonly sampled by removal from the air by filtration through a cellulose filter, fiberglass, or molecular sieve (membrane) type media [3]. portable dust sampler (sniffer, l-30) (fig.(1)) is used in collecting particulate matter by sucking air through the filter paper. the atmospheric particulate sampling process is carried out in baghdad city, al-zafaraniya region, inside a flat located in the first floor of a three stories building. the sampler level is fixed at the human breathing zone (approximately 1.5 m). at the laboratory, the filter papers are dissolved in a solution containing 5 ml of hno3 and several drops of hf. the lead concentration in the digested filter papers is measured by using atomic absorption spectrophotometer, model 210 vgp (buck, usa) (fig.(2)). the concentration of lead in air is calculated by using the following formula [4, 5]: t 1 p b v v*c c  (1) where cpb is the lead concentration in the ambient air (  g/m3), c is the lead concentration in the solution in ppm, v1 is the volume of the sample solution in ml, and vt is the volume of the sampled air (m3). the air suction vt (m3) is calculated from the following equation, based on the flow meter readings at the start and end of collection [6]: air suction = t qq es * 2        (2) where qs is the flow rate at the start of collection (m3/min), qe the flow rate at the end of collection (m3/min), and t the collecting time (min). data recorded include sampling place and date, time and flow rate readings at the start and end of sampling, useful meteorological data (weather condition, temperature, humidity, wind direction, wind velocity, etc.). fig.(1): portable dust sampler (sniffer, l-30) fig.(2): atomic absorption spectrophotometer, model 210 vgp (buck, usa) risk assessment risk, may be defined as the chance of encountering the potential adverse effects of human or ecological exposures to environmental hazards. in general terms, risk is the probability of harm or loss, which may also be considered as a product of probability and the severity of consequences [7]. risk assessment is the gathering of data that are used to relate response to dose. such dose-response data can then be combined with estimates of likely human exposure to produce overall assessments of risk [2]. the national academy of sciences suggests that risk assessment be divided into the following four steps [8]: nabeel hashim ameen, mohannad kh. mohammad and takrid m. nafae ijcpe vol.10 no.3 (september 2009) 21 hazard identification the first step in a risk analysis is to determine whether the chemicals that a population has been exposed to are likely to have any adverse health effects. lead poisoning can cause aggressive, hostile, and destructive behavioral changes, as well as learning disabilities, seizures, severe and permanent brain damage, and even death. children and pregnant women are at greatest risk. lead is absorbed by the blood following inhalation. it has been estimated that about one-third of the lead particles inhaled are deposited in the respiratory system, and that about half of these are absorbed by the bloodstream [2]. absorption also increases in children suffering from iron or calcium deficiencies. deposition of lead particles in the respiratory tract of children is 1.6 2.7 times than that of adults [9]. lead content in human blood varies according to age and sex, it tends to increase with age and males have more pb in their blood than females. mean pb content in children is sometimes higher than adults [10]. measurements made in actual communities suggest that an increase in airborne lead concentration of 1  g/m3 results in an increase of about 1–2  g/100 ml in blood lead level [2]. for european adults, values below 30  g/100 ml are considered normal, whereas pb concentration in blood above 70  g/100 ml is poisonous [4], with possible severe brain damage or death, occurs at levels somewhat above 80  g/100 ml [11]. dose – response assessment the fundamental goal of a dose–response assessment is to obtain a mathematical relationship between the amount of a toxicant to which a human is exposed and the risk that there will be an unhealthy response to that dose. for substances that induce a carcinogenic response, it is always conservatively assumed that exposure to any amount of the carcinogen will create some likelihood of cancer. for noncarcinogenic response, it is usually assumed that there is some threshold dose, below which there will be no response [2]. human exposure assessment risk has two components: the toxicity of the substance involved, and the amount of exposure to that substance. a human exposure assessment is itself a two-part process. first, pathways that allow toxic agents to be transported from the source to the point of contact with people must be evaluated. and second, an estimate must be made of the amount of contact that is likely to occur between people and those contaminants [2]. the mean exposure concentration of contaminants is used with exposed population variables and the assessmentdetermined variables to estimate contaminant intake. the intake for inhalation of airborne contaminants is estimated from equation below [7]: atbw edefetirca cdi * ****  (3) where cdi = intake by inhalation (mg/kg.day), ca = contaminant concentration in air (mg/m3), ir = inhalation rate (m3/hr), et = exposure time (hr/day), ef = exposure frequency (days/year), ed = exposure duration (years), bw = body weight (kg), at = averaging time (period over which the exposure is averaged, days). the inhalation rate varies with age, weight, sex, activity level, particulate size and other physical conditions; typical values are listed in table (1). typical body weights recommended by the epa are listed in table (2). table (1): typical inhalation rates (m3/hr) [12]: types activity level resting light moderate heavy adult male 0.7 0.8 2.5 4.8 adult female 0.3 0.5 1.6 2.9 average adult 0.5 0.6 2.1 3.9 child, age 6 y 0.4 0.8 2 2.4 child, age 10 y 0.4 1 3.2 4.2 table (2): epa recommended values for average body weight [4] risk characterization the final step in a risk assessment is to bring the various studies together into an overall risk characterization [2]. carcinogenic risk is a function of the chronic daily intake and the slope factor [7]: risk = cdi * sf (4) where risk = the probability of carcinogenic risk (dimensionless), cdi = chronic daily intake (mg/kg.day), sf = carcinogenic slope factor (kg.day/mg). age (y) weight (kg) 0 – 1.5 10 1.5 – 5 14 5 – 12 26 adult 70 risk assessment due to population exposure to lead particles emitted from domestic electrical generators 22 ijcpe vol.10 no.3 (september 2009) results and discussion the mean observed airborne lead concentrations is measured to be 6.614 3/ mg for the 3 kev generator and 3.368 3/ mg for the 0.9 kev generator. the mean observed airborne lead concentration emitted from the two generators is estimated to be 4.991 3/ mg , exceed the national standard established by the ministry of environment (iraq) and the international standards established by the epa (1.5 3/ mg ) and the world health organization who (1.5 3/ mg monthly, 0.5 3 / mg annual) [13]. this result indicates that there is some possible adverse health effects to the exposed individuals related to continuous inhalation of airborne lead particles at the mean observed concentration. multi-step risk assessment process is used in this study in estimation of the health risks to baghdad population exposed to airborne lead emitted from domestic electrical generators. the first step is making quantitative measurements of airborne lead concentrations by using portable dust sampler and flammable atomic absorption spectrophotometer. the second step is estimation of the internal exposure by evaluation of the daily intake of lead by the local inhabitants living in the area of the study. the last step is making a correlation between the dose administered and the response or damage produced by using a linear, no threshold dose-response model (eq.(4)). the chronic daily lead intake through inhalation pathway is estimated by substituting the appropriate values for the following parameters into eq.(3): ca = 6.614 3/ mg for 3 kev generator or 3.368 3/ mg for 0.9 kev generator = site-specific mean measured value, ir = 20 m3/day (adult, average) [14], ranges from 7.2 to 115.2 m3/day as a function of age, sex and activity level, et = 24 hours/day = pathway-specific values (dependent on the duration of exposure-related activities), ef = 365 days/year = pathway-specific value (dependent on the frequency of exposure-related activities), ed = 70 years (lifetime, by convention) [7], bw = 70 kg (adult, average) [15], 26 kg (child), at = 70 year = lifetime for carcinogenic effects (i.e., 70 years*365 days/years) [7]. eq.(3) is put into the following more convenient form for continuous exposure to airborne contaminants: bw irca cdi *  (5) an individual is assumed to weigh 70 kg (adult) or 26 kg (child) and breathe air at the inhalation rates listed in table (1), so the mean chronic daily intake is estimated by eq.(5). the lead dosage administered is correlated with the response or damage produced by using linear, no-threshold (lnt) dose-response model. the slope factor for inhalation of lead is taken to be 8.5*10-3 kg.day/mg [15]. using eq.(4), the results of risk assessment to baghdad’s population for different sexes, ages, and activity levels related to continuous inhalation of airborne lead at the mean observed concentrations are listed in table (3). the data listed in table (3) indicate that domestic electrical generators provide a potential for internal lead exposure to nearby individuals and result in detrimental health effects including increased incidence of cancer. children group is found to be at greatest risk. table (3): results of risk assessment: population group activity level resting light moderate heavy 3 kev generator adult male 13 per 1000000 15 per 1000000 48 per 1000000 92 per 1000000 adult female 5 per 1000000 9 per 1000000 30 per 1000000 55 per 1000000 average adult 9 per 1000000 11 per 1000000 40 per 1000000 75 per 1000000 child, age 6 y 20 per 1000000 41 per 1000000 103 per 1000000 125 per 1000000 child, age 10 y 20 per 1000000 51 per 1000000 166 per 1000000 218 per 1000000 0.9 kev generator adult male 6 per 1000000 7 per 1000000 24 per 1000000 47 per 1000000 adult female 2 per 1000000 4 per 1000000 15 per 1000000 28 per 1000000 average adult 4 per 1000000 5 per 1000000 20 per 1000000 38 per 1000000 child, age 6 y 10 per 1000000 21 per 1000000 52 per 1000000 63 per 1000000 child, age 10 y 10 per 1000000 26 per 1000000 84 per 1000000 111 per 1000000 ijcpe vol.10 no.3 (september 2009) conclusions 1. the mean observed lead concentrations emitted from the 0.9 kev generator (3.368 3/ mg ) and the 3 kev generator (6.614 3/ mg ) are found to be higher than the national ambient air quality standard (1.5 3/ mg ) [masters, 1991]. these results indicate that there is some probable risk to the human health related to continuous inhalation of contaminated air at the observed concentrations. 2. the health impact of the 3 kev electrical generator is found to be greater than that for the 0.9 kev generator under the same exposure conditions. 3. the predicted mean lead concentration in blood (7.48  g/100 ml) is found to be less than the poisonous concentration (70  g/100 ml) [4]. this result indicates that acute health effects related to blood poisoning by lead are excluded, but latent effects (such as cancer incidence) are expected. 4. the results of risk assessment listed in table (3) indicate that males are at greater risk than females because of higher inhalation rates. children are found to be the most sensitive group due to low body weight. 5. the exposure of the baghdad population to the airborne lead emitted from electrical generators causes possible long term adverse health effects including increased incidence of cancer and blood poisoning by lead. the results of toxicity analysis indicate that one extra cancer risk incident is expected for every 82501 persons living in baghdad dwellings related to continuous inhalation of airborne lead at mean observed concentration of 4.991  g/m3, or there is 12 extra cancer cases in a group of a million exposed individuals if they would all inhale lead at a rate of 36.43 mg per year instantaneously. nomenclature cpb lead concentration in the ambient air (g/m 3 ) c lead concentration in the solution ppm v1 the volume of the sample solution ml vt the volume of the sampled air (m 3 ) qs the flow rate at the start of collection (m 3 /min) qe the flow rate at the end of collection (m 3 /min) t the collecting time (min) cdi intake by inhalation (mg/kg.day) ca contaminant concentration in air (mg/m 3 ) ir inhalation rate (m 3 /hr) et exposure time (hr/day) ef exposure frequency (days/year) ed exposure duration (years) bw body weight (kg) at averaging time days risk the probability of carcinogenic risk dimensionless cdi chronic daily intake (mg/kg.day) references 1. shilu tong, yasmin e. von schirnding and tippawan prapamonto (2000), " environmental lead exposure: a public health problem of global dimensions", special theme – environment and health, world health organization, bulletin of the world health organization, 78 (9), 2000. 2. masters, gilbert m. (1991), "introduction to environmental engineering and science", prenticehall, inc., p.299-300. 3. kathren, ronald l. (1984), "radioactivity in the environment", 1st edition, hawood academic publishers. 4. al-samrae, omar s. (2005), “assessment of lead pollution at gasoline stations in baghdad city”, m.sc. thesis submitted to the environmental engineering department, al-mustansiriya university. 5. perry, r., young, r. (1977), “handbook for air pollution analysis”, wiley, london. 6. olkawa, k. (1977), "trace analysis of atmospheric samples", nigata college of pharmacy, al-aalsted press book, pp.35-36. 7. watts, richard j. (1998), "hazardous wastes, sources, pathways, receptors", john wiley and sons, inc., p.521-530. 8. national academy of sciences (1983), "risk assessment in the federal government: managing the process", national academy press, washington, dc. 9. epa (1986), “air quality criteria for lead”, u.s. environmental protection agency, environmental criteria and assessment office, research triangle park, nc, vol.i of iv. 10. waldren, h.a. and stofen, d. (1974), “sub-clinical lead poisoning”, academic press, london and new york. 11. epa (1977), “air quality criteria for lead”, u.s. environmental protection agency, washington, dc. 12. epa (2000), “uranium in soil, individual dose calculator”, soil screening guidance for radionuclides (ssrg), washington, d.c., (internet). 13. davis, m.l., and cornwell, d.a. (1998), "introduction to environmental engineering", 3rd edition, mc-graw hill, new york. 14. epa (1989), "exposure factors handbook", publication epa/600/8-89/043, u.s. environmental protection agency, washington, dc. 15. epa (1996), iris database, u.s. environmental protection agency ijcpe vol.9 no.3 (september 2008) iraqi journal of chemical and petroleum engineering vol.9 no.3 (september 2007) 17-24 issn: 1997-4884 separation benzene and toluene from btx using zeolite 13x abdul-halim abdul-karim mohammed * and mohand kadir baki * chemical engineering department college of engineering university of baghdad – iraq abstract this work deals with the separation of benzene and toluene from a btx fraction. the separation was carried out using adsorption by molecular sieve zeolite 13x in a fixed bed. the concentration of benzene and toluene in the influent streams was measured using gas chromatography. the effect of flow rate in the range 0.77 – 2.0 cm3/min on the benzene and toluene extraction from btx fraction was studied. the flow rate increasing decreases the breakthrough and saturation times. the effect of bed height in the range 31.6 – 63.3 cm on benzene and toluene adsorption from btx fraction was studied. the increase of bed height increasing increases the break point values. the effect of the concentration of benzene in the range 0.0559 – 0.2625g/cm3 and toluene in the range 0.144 – 0.21 g/cm3 was studied. the increasing of inlet solute concentration increases the slope of the breakthrough curve. the amount of toluene adsorbed in the packed bed at any time is higher than that of benzene while it decreases after the saturation time. the best operating conditions in this work for benzene and toluene adsorption are 0.77 cm3/min of feed and 31.6 cm bed height of zeolite 13x. introduction generally in the oil industries aromatics are recovered by liquid – liquid extraction of reformate using selective polar solvents like dimethylsulfoxide (dmso) [1], n – formylmopholine (nfm) [2], and sulfolane [3]. the aromatics and solvent are separated by distillation and then xylenes are separated from the aromatics mixture by extractive distillation. adsorption is the fixation of molecules by reversible reaction on the surface of a solid. the adsorption of compound on zeolite is the sum of three different phenomena; these are chemisorption, forming the first layer at low partial pressures, physisorption, due to the formation of multiple layers by hydrogen bonding in the alumina pores and capillary condensation, where localized condensation takes place at temperature above that of the bulk fluid's dew point [4]. contrary to other adsorbents like activated alumina and silica; zeolites have a high adsorption capacity at low partial pressure. adsorption capacity decreases with increasing temperatures, but zeolite keep their efficiency for drying up to 100 o c, whereas alumina has it is more favorable adsorption characteristics below 50 o c [5]. the present study is a trial to separate benzene and toluene from btx fraction supplied from arab company for detergent and chemicals by adsorption technique using molecular sieve zeolite 13x. experimental work this investigation includes the study of effect of feed flow rate in the range 0.77 – 2.0 cm3/min, bed length in the range 31.6 – 63.3 cm, concentration of benzene in the range 0.0559 – 0.2625 g/cm3 and concentration of toluene in the range 0.144 – 0.21 g/cm3 on the benzene and toluene separation from btx fraction by using zeolite 13x in the packed bed column. materials feed stock university of baghdad college of engineering iraqi journal of chemical and petroleum engineering removal of asasbn sdfs fs f sf sdfsdfsdf fsdfsdfsdfs fsdfsdfsd 2 ijcpe vol.9 no.3 (september 2008) the feed stock used in this study is btx fraction supplied from arab company for detergent and chemicals which is extracted from the reformate of beiji refinery using sulfolane extraction process. the properties of btx fraction are given in table (1). table (1) properties of btx fraction no. properties values 1 api gravity 30.62 2 specific gravity at 60 of/60 of 0.8728 3 aromatic content, wt % benzene toluene c8 – aromatics c9 – 10 aromatics 6.90 22.25 40.52 30.32 zeolite the adsorption column is packed with 13x molecular sieve obtained from "rhone poulenc" with bulk density 0.64 g/cm3, extrudate diameter 1.6 mm, total pore volume 0.285 cm3/g, apparent porosity 0.36, bed void fraction 0.4 and normal pore diameter 10 ao. adsorption equipment an experimental apparatus shown in fig. (1) is constructed for adsorption of btx fraction by molecular sieve 13x. it consists of 2.5 liter glass container for feed, connected with the adsorption column by a plastic tube. the q.v.f column of adsorption has 1.5 cm inside diameter and 100 cm long. it is packed with 13x molecular sieve adsorbent. the bottom of adsorption column was fitted with piece of cloth to support the zeolite bed. to reduce the channeling and bad distribution of feed through the bed, balls of polyvinyl chloride were used. these balls are non – reactive with adsorbent and adsorbate. the average length of polyvinyl chloride balls in top of bed is 9 cm and in the bottom is 8 cm. balls of the bottom of adsorption column protect the adsorption bed from the mechanical force and attrition. glass receiver is used for collection of effluent. fig. 1: experimental apparatus gas chromatography analysis the gas chromatography apparatus of type philips varian 3300 was used for analysis of benzene and toluene in effluent. the carrier gas used is nitrogen purity of 99 % supplied from al-mansour company. the recorder packed model 621 type was used and the integrator packed model 602 type was used. results and discussion effect of feed flow rate on benzene and toluene separation the effect of feed flow rate in the range 0.77 – 2.0 cm3/min on the benzene and toluene separation from btx fraction was studied. figures (2,3, and 4) show the breakthrough curves for adsorption of benzene and toluene using flow rate 0.77, 1.00 and 2 cm3/min, respectively, while figure (5) and (6) show the effect of the flow rate on the adsorption of benzene and toluene respectively. examining these figures, it can be seen that at low flow rate the amount of benzene and toluene adsorbed is higher than that obtained with higher flow rate at a given time. the flow rate increasing decreases the break point time and saturation times, because the increasing in the flow rate leads to decreasing the contact time between ijcpe vol.9 no.3 (september 2008) the adsorbate and the adsorbent along the adsorption bed. for example, at flow rates 0.77, 1.00, and 2.00 cm3/min benzene reaches the breakthrough concentration c/co = 0.1 at times 25, 10, and 5 min respectively. using the flow rates 0.77, 1.00, and 2.00 cm3/min and time 25 minutes the values of c/co for toluene are 0.64, 0.849, and 1.022 respectively. the short break point time of toluene is because toluene has the higher concentration in the influent stream therefore higher driving force between adsorbate and adsorbent was obtained. as shown in fig. (5) and (6) the best volumetric flow rate was q = 0.77 cm3/min. 0 0.2 0.4 0.6 0.8 1 1.2 1.4 0 100 200 300 400 500 time (min) c /c o benzene toluene fig. 2: breakthrough curves for adsorption benzene and toluene at q = 0.77 cm 3 /min and z = 19 cm 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 0 50 100 150 200 250 300 350 400 time (min) c /c o benzene toluene fig. 3: breakthrough curves for adsorption benzene and toluene at q = 1 cm 3 /min and z = 19 cm 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 0 50 100 150 200 250 300 350 400 time (min) c /c o benzene toluene fig. 4: breakthrough curves for adsorption benzene and toluene at q = 2 cm 3 /min and z = 19 cm 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.5 0.75 1 1.25 1.5 1.75 2 flow rate cm 3 /min c /c o t=10 min t=150 min t=250 min fig. 5: the effect of feed flow rate on benzene adsorption at constant bed height z = 19 cm 0 0.2 0.4 0.6 0.8 1 1.2 1.4 0.5 0.75 1 1.25 1.5 1.75 2 flow rate cm 3 /min c /c o t=10 min t=50 min t=150 min fig. 6: the effect of feed flow rate on toluene adsorption at constant bed height z = 19 cm removal of asasbn sdfs fs f sf sdfsdfsdf fsdfsdfsdfs fsdfsdfsd 4 ijcpe vol.9 no.3 (september 2008) effect of bed height on benzene and toluene separation the effect of bed height in the range 31.6 – 63.3 cm on benzene and toluene separation from btx fraction using constant feed flow rate 1.00 cm3/min was studied. as shown from figures (7 – 11). examining these figures, it can be seen that the break point time values increase by bed height increasing knowing that increasing the bed height will be accompanied by an increase in the bed cost. at bed heights 31.6, 44.3, and 63.3 cm, benzene reaches the breakthrough concentration c/co = 0.1 at times 2, 3, and 5 min, respectively. for toluene at bed height 31.6, 44.3, and 63.3 cm and time 5 minutes the values of c/co are 0.3, 0.151, and 0.130 respectively. the use of long bed height will give additional spaces for benzene and toluene molecules to be adsorbed, further more increasing the bed height will give a sufficient contact time for these molecules to be adsorbed on the zeolite 13x. 0 0.2 0.4 0.6 0.8 1 1.2 1.4 0 100 200 300 400 500 time (min) c /c o benzene toluene fig. 7: breakthrough curves for adsorption benzene and toluene at q = 1.0 cm 3 /min and z = 31 cm 0 0.2 0.4 0.6 0.8 1 1.2 0 50 100 150 200 250 300 350 400 450 500 time (min) c /c o benzene toluene fig. (8) breakthrough curves for adsorption benzene and toluene at q = 1.00 cm 3 /min and z = 44.3 cm 0 0.2 0.4 0.6 0.8 1 1.2 0 100 200 300 400 500 time (min) c /c o benzene toluene fig. 9: breakthrough curves for adsorption benzene and toluene at q = 1.00 cm 3 /min and z = 63.3 cm 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 30 35 40 45 50 55 60 65 bed height cm c /c o t=25 min t=50 min t=75 min t=100 min fig. 10: the effect of bed height on benzene adsorption at constant feed flow rate q = 1 cm 3 /min 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 30 35 40 45 50 55 60 65 bed height cm c /c o t=5 min t=25 min t=50 min fig. (11) the effect of bed height on toluene adsorption at constant feed flow rate q = 1 cm3/min ijcpe vol.9 no.3 (september 2008) effect of feed concentration on benzene and toluene separation the effect of concentration of benzene in the range 0.0559 – 0.2625 g/cm3 and concentration of toluene in the range 0.144 – 0.21 g/cm3 was studied, as shown in figures 12 and 13 , respectivly. these figures show that the increasing in inlet concentration will lead to increase driving force and consequently increasing the adsorption rate and leads to quick saturation of the adsorbent with benzene and toluene there by decreasing the breakthrough time of benzene and toluene. the increasing the inlet solute concentration increases the slope of the breakthrough curve. for example, at benzene initial concentration 0.0559, 0.105, 0.175, and 0.2625 g/cm3 and time 25 min the values of c/co are 0.315, 0.495, 0.638, and 0.765, respectively. for toluene initial concentration 0.144, 0.181, and 0.21 g/cm3 at time 50 min the values of c/co are 0.551, 0.181, and 0.21 g/cm3 ,respectively. as shown in fig. (13) when p and m-xylenes begin to adsorb some of the toluene is re-adsorbed. this leads to rollup the concentration of toluene in the effluent stream to a level above that of feed. 0 0.2 0.4 0.6 0.8 1 1.2 1.4 0 50 100 150 200 250 300 350 400 450 500 time (min) c /c o co = 0.0559 co = 0.105 co = 0.175 co = 0.2625 fig.12: breakthrough curves at different initial concentration of benzene at q =1 cm 3 /min &z = 44.3 cm 0 0.2 0.4 0.6 0.8 1 1.2 0 50 100 150 200 250 300 350 400 450 500 time (min) c /c o co = 0.144 co = 0.181 co = 0.21 fig. 13: breakthrough curves at different initial concentration of toluene at q = 1 cm 3 /min & z = 44.3 cm conclusions 1. the time required to reach adsorbent saturation is increased by decreasing flowrate. 2. the time of break points increases with bed length increasing for benzene and toluene extraction from btx fraction. 3. the amount of benzene and toluene adsorbed by molecular sieve 13x increases with increasing the feed stock concentration. 4. the best operating condition in this work for benzene and toluene adsorption are 0.77 cm3/min of feed and 31.6 cm bed height of zeolite 13x. reference 1 choffe, b., raimbault, c., and navarre, f. p., hydrocarbon processing, vol. 45, may, p. 188, 1966. 2 stein, m., "recover aromatics with nfm", april, p. 139, 1973. 3 deal, c. h., evans, h. d., oliver, e. d., and papadopoulos, m. n., petroleum refiner, vol. 38, september, p. 185, 1959. 4 axens group technologies, "activated alumina and molecular sieves", www.axens.net, 2003. 5 sanchez, m. g., ph. d. thesis, university of mexico, 2003. http://www.axens.net/ removal of asasbn sdfs fs f sf sdfsdfsdf fsdfsdfsdfs fsdfsdfsd 6 ijcpe vol.9 no.3 (september 2008) available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.19 no.4 (december 2018) 1 – 11 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: aya abbas najim, email: ayaaabbas@yahoo.com, ahmed a. mohammed, email: ahmed.abedm@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. biosorption of methylene blue from aqueous solution using mixed algae aya abbas najim and ahmed a. mohammed environmental engineering department, college of engineering, university of baghdad abstract a mixture of algae biomass (chrysophyta, cyanophyta, and chlorophyte) has been investigated for its possible adsorption removal of cationic dyes (methylene blue, mb). effect of ph (1-8), biosorbent dosage (0.2-2 g/100ml), agitated speed (100-300), particle size (1304-89µm), temperature (20-40˚c), initial dye concentration (20-300 mg/l), and sorption–desorption were investigated to assess the algal-dye sorption mechanism. different pre-treatments, alkali, protonation, and cacl2 have been experienced in order to enhance the adsorption capacity as well as the stability of the algal biomass. equilibrium isotherm data were analyzed using langmuir, freundlich, and temkin models. the maximum dye-sorption capacity was 26.65 mg/g at ph= 5, 250 rpm, 89µm, 25˚c, and 50 mg/l as initial concentration. four kinetic models were tested, pseudo first order, pseudo second order, intraparticle diffusion and elovich model. taking into account the analysis of the (ssr and x 2 ), the data were best fitted to temkin isotherm model. the pseudo-second order with higher coefficient of determination fitted the data very well. thermodynamic parameters (γg 0 , γh 0 , γs 0 , ea and s*) at temperature ranges of 293–313 k demonstrated that biosorption is an endothermic, spontaneous reaction and higher solution temperature favors mb removal by adsorption onto algae biomass. results show that adsorptiondesorption process lasts for five cycle before losing its efficiency and the recovery efficiency increased up to 80.52%. keywords: cationic dye, adsorption, desorption, algae, endothermic received on 20/02/0206, accepted on 01/00/0206, published on 12/00/0206 https://doi.org/10.31699/ijcpe.2018.4.1 1introduction many industries, such as textiles, plastic, leather, dye manufacturing, sugar manufacturing, carpet, pulp, cosmetic and paper use pigments to color their products ‎[1]. serious pollution of surface waters, ground waters and soil is caused by the colored effluent discharged by these industries. among the above cited industries, textile and dye manufacturing industries are the main source of dye contamination that on discharge creates serious environmental problems ‎[2]. synthetic dyes are dangerous toxic organic compounds which have a major negative environmental impact, and cannot degrade completely due to the presence of the atomic rings that afford high thermal, physiochemical, and optical stability ‎[3], ‎[4]. therefore the present of these dyes in water is unwanted due to inhibiting photosynthetic action, affects the nature of the water so decrease site value for swimming, boating and fishing, even at low concentrations the physiochemical properties of the ecosystem are changed and prevent light penetration into water, it is hard to be treated by conventional treatment system. biodegradation or biological treatment of textile industry dyes is ineffective, time-consuming and very difficult because such dyes must have a high photolytic and chemical stability ‎[5]. methylene blue (mb) dye has several side effects such as eye burns, dyspnea, a burning feeling while ingestion through the mouth, vomiting, profuse, plentiful sweating, blood problems, nausea, and mental distraction ‎[5], ‎[6], ‎[7]. various methods for dye contaminant treatment include ozone treatment, photochemical oxidation, cation exchange membranes, ultrafiltration, nano-filtration, electro-chemical degradation, reverse osmosis, and anaerobic degradation ‎[8]. nevertheless, those mentioned treatments have many limitations, such as expensive, corrosion, low efficiency, require sensitive operating conditions, consume large amount of energy and chemical reagents, imperfect removal of colored, and produce huge quantity of sludge ‎[3], ‎[9]. compared to the above cited methods, adsorption has been proven to be more effective, because it offers many benefits such as simple to design, cost effective, nonsensitivity to toxic materials, and easy to operate. adsorption has some limitations such as problems faced in segregating sorbent from sorbate in order to be regenerated and spent adsorbent may be considered a hazardous waste. adsorption is traditionally done by using activated carbon. https://doi.org/10.31699/ijcpe.2018.4.1 a. a. najim and a. a. mohammed / iraqi journal of chemical and petroleum engineering 19,4 (2018) 1-11 2 yet, the high cost of the activation processes limits its usage in wastewater treatment processes, ineffectual against disperse and vat dyes moreover, there is regeneration problems, as well as, after adsorption process it is difficult to separate the treated activated carbon from the bulk solutions ‎[10], ‎[11]. adsorption is a multi-step process, comprising of four consecutive elementary steps in the case of biomass; the adsorption of solute from solution by adsorbent with pores, the transport of the moving contaminating ions to the outer surface of the biomass (film diffusion), the movement of the solute from the particle surface into interior site by pore diffusion, and finally the adsorption of the adsorbate that takes place into the active sites inside adsorbent particle. the third phenomenon, between these three processes, is take into consideration to be faster and is not the step that limits organic compounds uptake ‎[6], ‎[10]. over the last decade, many paths have been done to promote inexpensive and effective adsorbents to remove contaminants from a set of starting materials such as agriculture waste and biological material (bacteria, fungi, yeast, algae, and plants) ‎[12], ‎[13]. algae is one of the most favorable sources of protein supplements, biofuel, biosorbent, and organic fertilizer owing to their advantages like capacity to use fresh, marine or wastewater, reduce greenhouse gas from the environment, do not compete with food yields, and non-requirement of fertile land [14]. it is an efficient biosorbent to be used for dyes removal from wastewaters discharges by industrial activities and gainful, due to the functional groups (amino, hydroxyl, sulfate, and carboxyl) located on the cell surface, which play an active role in the biosorption process ‎[15]. maurya et al [14] showed that the de-oiled algal biomass dab (10 g/ l) removes 86% of the dye (50 mg/ l) in 5 minutes under static condition and nearly 100% in 24-hours with agitation at 150 rpm, which indicates the mb removal by dab in static conditions is more feasible as it requires lesser energy input. the objective of this work is to examine the ability of mixed algae as an adsorbent for the removal of cationic (basic) dye from simulated wastewater under various ph values, algae dosage, contact times, initial methylene blue dye concentrations, temperature, different shaking speed and different algae particles size. moreover different substances with different concentration for algae pretreatment, and desorption recovery process by using different concentration of nitric acid to reuse the biomass was also evaluated. equilibrium and kinetic models were used to estimate the sorption potential and the rate of reaction respectively. 2experimental work 2.1. preparation of biomass and adsorbate mixed algae consist of (80% chrysophyta, 5% cyanophyta, 14% chlorophyte, and 1% microscopic animals). these algae were collected from the tigris river, iraq. after that, the collected algae was washed many times with tap water to get rid of impurities, dirt and other unwanted materials such as (non-vertebrate animals, small worms, crustaceans, bird feathers), then with distilled water twice to ensure clearness. the washed algae was left under the sun for three days to dry and then dried in an oven (model: f62700, barnstead thermolyne, germany) at 60°c for 3 h to ensure that the sample is dried completely. the dried algal biomass were cut off, crushed in a mechanical mill and sieved, average size of (1304, 500, 177, and 89) 𝛍m particle diameters. thirty grams of dried algae biomass 177 µm diameter were treated with 500 ml of naoh, cacl2 and hcl for 1 hr at different concentrations (0.05 m, 0.1 m, and 0.5 m), then put in a shaker at 50 rpm for 1 hr to improve the biosorption capacity to methylene blue. the mixture was filtered, washed several times with distilled water till the solution ph value reached 7.0 and then the algal biomass dried at 60 ˚c for a period of 4 hr in the oven. the dye utilized in this study was methylene blue (ci 52015; cas no=7220-79-3; chemical formula: c16h18cln3s.3h2o; molecular weight = 373.90 g/mole.; minimum assay=99.0%; himedia), a cationic thiazine. synthetic aqueous stock solution 1000 mg/l of methylene blue was prepared by dissolving 1.0 g of mb in 1l of distilled water. for all experiments, the concentration of mb was determined by an uv-visible spectrophotometer (cary-100 conc., varian, usa) at a wavelength corresponding to the maximum absorbance of the dye solution (λmax= 662 nm), using 0.1 n of naoh and hcl to get the desired value of the initial ph. hno3 (0.05m and 0.1) m was used for sorbent desorption. 2.2. batch experiments the experiment on the effects of ph was conducted by mix-up 0.5 g adsorbent dosage with 50 ppm of mb solution at different ph (1-8), and then the flasks were shaken at 200 rpm for 2 hr. for studying the influence of various biomass dosages on the mb percentage removal, experiments were conducted by varying the biomass dosage (0.2-2 g/100 ml) with 50 mg/l mb solution. shaking speed effects on mb adsorption was investigated by using 50 mg/l solution at various shaking speed (100, 200, and 300 rpm) with best values of biomass dosage and ph. to investigate whether particle size (1304, 500, 177, and 89 µm) affected the removal of mb, the experiment was carried out using 50 mg/l of mb solution (ph=5, 7g/l adsorbent, 250 rpm shaking speed, and 120 min shaking time). to study the effect of shaking time and initial mb concentration on the percentage removal, experiments were conducted by mixing 0.7 g/100 ml adsorbent dosage with different mb concentrations (20, 50, 100, 200, and 300 mg/l) for 3 hr. at best conditions obtained from the previous experiment. the impact of the temperature on mb adsorption was studied by changing the temperature (20, 25, 30, 35, and 40) using shaking incubator (iso 9001, model: lsi-3016a, no.b110416002, korea) at the best conditions obtained from the previous tests. a. a. najim and a. a. mohammed / iraqi journal of chemical and petroleum engineering 19,4 (2018) 1-11 3 the results from these experiments were used to calculate the associated thermodynamic parameters. adsorption–desorption experiments were carried for (0.05 m and 0.1 m hno3) discretely up to five cycles. a single cycle system is composed of adsorption step (120 min) followed by desorption step (60 min) (ph, 5.0; biosorbent, 0.7g/100 ml; agitation, 250 rpm; dye concentration, 100 mg/l; temperature, 25˚c; adsorption contact time, 120 min; desorption time, 60 min). the dye loaded algal biomass after adsorption, was filtered, dried in air then reintroduced into desorption solvent (0.05 m and 0.1m) hno3 (0.7 g/ 100 ml, hno3). the biosorption capacity and removal efficiency were calculated as follows ‎[16]: qe = ( ) (1) % removal efficiency= ∗100 (2) where ci and ce are the initial and equilibrium dyes concentration in the solution (mg/l), v is the volume of solution in (l), and m the quantity of biomass applied in (g). the eluting efficiencies of the desorbent ed are expressed as follows ‎[17]: e (%) = x 100 (3) mad: total adsorbed quantity of mb, mg/l , md :the mb mass desorbed, mg/l 3results and discussion 3.1. ft-ir analysis the purpose behind the ftir analysis is to identify the different functional groups found in algae that's responsible for the adsorption process and to pin point the changes that take place in the algae biomass structure ‎[18]. fig. 1 shows the results of the notice ir absorption frequencies in different regions for algae before and after biosorption of mb. the peaks show in the ftir spectrum were allocated to several functional groups according to their own wave numbers. the band at 3700-3000 cm -1 is o-h and n-h stretching of (alcohols, phenols, and carboxylic acids), and 3400-3200 cm -1 is stretching of polymeric compounds; 2962-2853 cm -1 interval is stretching vibration of c-h especially alkyl chains, intense band at 2000-2500 cm -1 interval for carboxylic acid, 1720-1431 cm -1 interval for the presence of amide, carboxylates, sulfonates, and ketone groups. the c-o, c-c, c-oh stretching vibration referred to peaks in the region of 1359-1041 cm 1, while bands in the fingerprint regions (900–750 cm −1 ) referred to the aromatic –c–h groups. from figure 1, we noticed that after biosorption of the dye molecules, a shifting or disappearance of some peaks as well as the emergence of new ones. the reason behind these shifts is the binding process that occurs on the surface of the biomass. (a) (b) fig. 1. ftir peaks of transmittance of mb, (a) before adsorption, (b) after adsorption 3.2. effect of ph the ph is a significant feature impacting the adsorption studies. this was because ph effects the function groups on the biomass surface and determines dye solubility in the aqueous solution ‎[19]. dependence of organic and inorganic biosorption on ph is associated to both the ionization state of functional groups of the adsorbent which affects the availability of binding sites and the contaminants chemistry (complexation by organic and/or inorganic ligands, hydrolysis, precipitation and redox reactions) in the solution ‎[20]. the effect of solution ph on the sorption of dyes on the sorbent was studied by altering the ph in range (1-8). the increase in ph cause an increase in percentage sorption as depicted in fig. 2. the minimum sorption was observed at low ph (ph= 1.0-4.0) due to the existence of higher h + ion concentration which is favored sorption in comparison with other cationic pollutants. at higher concentration of h + ions, the biomass surface will be farther positively charged thus reducing the attraction force between adsorbent and cation pollutant ‎[16]. at ph values (5–8), the removal percentage of dye was almost constant. a. a. najim and a. a. mohammed / iraqi journal of chemical and petroleum engineering 19,4 (2018) 1-11 4 the solute (dye ions) uptake can be related to the chemical structure of the solute in the solution and also to the active sites located at the biomass surface. the removal percentage of methylene blue (mb) reaches maximum at ph 5, no significant altered beyond ph 5 was observed because when ph is high, the adsorbent particles surface may be negatively charged causing the enhancement the cationic dyes through electrostatics forces of attraction. fig. 2. ph effect on the removal efficiency of mb (m=0.5 g/100 ml, ci= 50 mg/l, t= 25˚c, 89µm, speed= 200 rpm, and time=120 min) in general nontreated algal biosorbent has alkali and alkaline earth metals such as na + , mg 2+ , k + and ca 2+ which are essentially tied to the acid functional groups of the algae and were attained from sea water [20]. the ph and ec were measured at different time intervals during the agitation process. fig. 3 shows the increase in the electrical conductivity (ec) and ph values with time. in this case, the cations of light metals were being eluted from the algal biomass during the experiments, while the cationic dyes were being sorbed onto the biomass. it was noticed that the solution final ph was greater than the initial value, attributed to ion exchange mechanisms, hence, the witnessed release light metals well-adjusted the uptake of cation. accordingly, the light metals released, when algae biomass reacts with the cationic pollutants causing an increase in the ph as a result of formation of light metal alkalis [21]. fig. 3. ph and ec evolution as a function of time dyes biosorption, (m=0.7 g/100 ml, t=25˚c, ci= 50 mg/l, 89 µm at 200 rpm) 3.3. effect of biomass dosage the doses (mass) of adsorbent effects on the adsorption of mb are shown in fig. 4. the biomass dosage is an important parameter used to determine the capacity of biosorbent for specific initial concentration ‎[3]. in this paper different amount of algae biomass (0.2-2 g/ 100 ml) were used. an increasing amount of algal biomass may be able to fully adsorb the pollutants or reach an equilibrium state when reaching a plateau at a fixed concentration of each pollutant ‎[3], ‎[11]. it is obviously noticed that the removal percentage of mb increases from 61.94 to 92.43%, as the algae dosage increases from 0.2 to 0.7 g. after some point (above 0.7 g), adsorption removal efficiency was steady credited to a screen effect between adsorbent ‎[21], or the observed behavior occurred because at the initial stage there were sufficient binding sites for the complexation of dye molecules and increasing the dose beyond 0.7 g resulted in the establishment of equilibrium between the cationic dyes bounded to biosorbent and those remaining un-adsorbed in the mixture ‎[12], or because high adsorbent amounts are known to cause agglomeration and accordingly reduce the distance between biomass leading to protecting the binding sites from contaminants ‎[10]. increasing biomass concentrations results in increases final bio-removal although it has negative effects on biosorption capacity because fixed initial concentration leads to unsaturated active site on biomass surface and the increase in the biomass concentrations cause particle aggregation ‎[3]. fig. 4. effect of sorbent amount on the removal efficiency of mb by algae biomass (ph 5, t= 25˚c, ci=50 mg/l, 89 µm, speed = 200 rpm and time=120 min) 3.4. effect of shaker speed with suitable agitation speed, the resistance of mass transfer can be reduced. the solution rate of diffusion (from the bulk liquid to the liquid boundary layer surrounding particles) becomes higher because turbulence improves and the liquid boundary layer thickness is reduced, as a result of increasing the agitation rate ‎[13]. shaker speed affects the spreading of dye molecules in solution and also disrupts the film resistance surrounding the adsorbent particles by influence the uptake of dye molecules. 0 20 40 60 80 100 0 2 4 6 8 10 r e m o va l% ph a. a. najim and a. a. mohammed / iraqi journal of chemical and petroleum engineering 19,4 (2018) 1-11 5 when speed of the shaker increased from 100 to 300 rpm, the time required to achieve equilibrium was reduced, so the available biomass surface area increases due to the deficiency of aggregation of the biosorbent that finally leads to rapid adsorption of mb ‎[14]. furthermore, these results obviously show that 250 rpm is adequate to gain maximum percentage removal of mb as shown in fig. 5, no significant altered beyond this point was observed because the solution has reached equilibrium. fig. 5. effect of shaker speed on the removal efficiency of mb (ph 5, m= 0.7 g/100 ml, t= 25˚c, ci= 50 mg/l, 89 µm, and time=120 min) 3.5. effect of particle size of biomass surface area of the biomass is a key parameter for sorption. fig. 6 shows the relationship between the size of sorbent particle and the removal efficiency. the results show an adverse relation between the removal efficiency and particle size, the former increase with later decrease. the higher sorption level attained by the smallest sorbents particle size connected to the notation that smaller particle sizes provide large surface areas and exhibit faster adsorption more than that of sorbents with lower surface area. the removal efficiency decreased from 93.19 to 66.82 % as the particle size increased from 89 to 1304 µm. fig. 6. effect of particle size diameter of sorbent on the removal effeciency of mb (ph 5, m= 0.7 g, t= 25˚c, speed= 250 rpm, ci= 50 mg/l, and time=120 min) the diffusional resistance to mass transfer is greater for large particles, but the smallest size allows very fast removal kinetics if the adsorption is to be primarily a surface phenomenon ‎[8]. there is a tendency as fine particles takes lesser time to equilibrium in shorter time. 3.6. effect of initial concentration with time the initial concentration of mb affords a main driving force to outweigh all mass transfer resistance between the aqueous and solid phases ‎[8]. the experiments were performed at distinct initial mb concentrations (20 to 300 mg/l). from fig. 7 it notes that the percentage removal decreases from: 98.97 to 65.48%, as the initial concentration increased from 20 to 300 mg/l. one of the most essential parameters affecting the biosorption efficiency, modeling and designing the adsorption process in the industry is the contact time. it was inferred that the amount of mb adsorbed was fast for the first 15 min and after that, a slower pace (15–60 min) for the range 20-100 mg/l, (15-120 min) for 200-300 mg/l, and finally reached saturation. the available sites saturation occurs much earlier when the solution contains a higher initial dye concentration, resulting in a solution with high dye content at equilibrium ‎[14]. it can be seen that the percentage removal was not altered significantly when the concentration increased from 20-50 mg/l because the dosage of algae may have sufficient sites that can be exchanged for the above mentioned range. however, by increasing concentrations to 100, 200 and 300 mg/l, a sharp reduction in percentage removal was obvious due to insufficient exchangeable sites in the biomass to accumulate these concentrations. pirbazari et al ‎[10] show that 80 min duration is the contact time was needed for mb solutions with initial concentrations of 50–200 mg/l to reach equilibrium. fig. 7. effect of initial concentration with time on the removal efficiency of mb (ph 5, m= 0.7 g, 25˚c, speed= 250 rpm, 89 µm, and time=180 min) 3.7. effect of temperature and thermodynamic parameter: temperature has a vigorous influence on adsorption process as it can affect the process by an increase or decrease in the amount of adsorption. a. a. najim and a. a. mohammed / iraqi journal of chemical and petroleum engineering 19,4 (2018) 1-11 6 yu and luo, ‎[9] show that temperature is an essential factor for the real application of mac as most of the textile dye effluents are produced at relatively high temperature. the results are plotted in fig. 8 and the values of thermodynamic parameters are tabulated in table 1 which shows the adsorption efficiency of mb onto algae biomass at five different temperatures of 20, 25, 30, 35, and 40 o c. it can be seen that with increasing temperature the percentage removal increases, suggesting that endothermic nature of the process. this effect may be due to the fact that at higher temperature, an increase in active sites occurs due to bond rupture ‎[10], or an increasing of the surface area available for the sorption because pores in algae were enlarged, penetration of contaminants within the pores of algae, diffusion, and the equilibrium capacity of the adsorbent will be modified for a particular adsorbate ‎[9]. the removal efficiency increase as temperature increase till it reaches 40˚c. at higher temperature, texture of biomass was changed, as a results damaging and reduce number of functional groups, that’s why temperature was limited to 40˚c ‎[18]. fig. 8. effect of temperature on the removal efficiency of mb (ph 5, m= 0.7 g, ci= 50 mg/l, speed= 250 rpm, 89 µm, and time=120 min) a linear plot with intercept of ln s*and slope of ea/r will be observed by plotting (1−θ) against 1/t. the positive values of γh° and ea reveal that: adsorption is endothermic and higher solution temperature favors mb removal by adsorption on algae biomass ‎[3]. similarly, the γs° values are positive indicating increasing in randomness at the solid/ solution interface during their sorption. the negative values of ∆g at all temperatures range studied showed that the process is spontaneous with high affinity of mb to dried algae ‎[3]. the value of sticking probability s* is found very close to zero indicating that the adsorption process follows chemisorption [10]. ( ) ( ) (4) γg= γhγst (5) kc = (6) s* = (1 − θ) exp ( ) (7) θ = (1 – ) (8) where: kc stands for the equilibrium constant, cad stands for the adsorbed concentration of mb on the adsorbent per liter of the solution at equilibrium (mg.l -1 ), ce is the equilibrium concentration of mb in the solution (mg.l -1 ), γh° stands for the biosorption process enthalpy (kj/mole), r stands for the universal gas constant (8.314 j/mole. k), γs° stands for the biosorption process entropy (j/k. mole), γg stands for the gibbs free energy of biosorption (kj/mole), t stands for the solution temperature (k), θ is surface coverage, s* is sticking probability, and ea is activation energy. table 1. the thermodynamic parameters for the sorption of mb on algae biomass t(k) ∆g o (kj/mol) ∆s o (j/mol k) ∆h o (kj/mol) ea (kj/mol) s* 071 -5.558 190.615 50.2922 47.645 2.986e-10 076 -6.511 121 -7.464 126 -8.417 101 -9.370 3.8. desorption the recyclability of an adsorbent is of fundamental importance in industrial practice for pollutant removal from wastewater ‎[22]. desorption of the adsorbed mb from the tested algae biomass were studied in a batch system. the dye adsorbed onto biosorbent was eluted with various concentrations of nitric acid. more than 80% of the adsorbed mb was desorbed from the biosorbent by using 0.1 m hno3 in the first cycle. if desorbent achieves the assigned standards, it is promising to recover the adsorbate in concentrated form and to regenerate the biosorbent in order to use it in another biosorption cycle. in order to show the reusability of algae biomass, adsorptiondesorption cycle of pollutants was repeated five times by using the same preparations. the recovery percentages using two concentrations of hno3 from algae biomass are calculated from eq. (3). nitric acid was used for this purpose because at acidic condition the adsorbent surface protonate by replacing the adsorbed pollutants on the adsorbent surface leading to desorption of positively charged pollutants or due to the fact that most biosorption exhibit an ion-exchange mechanism for cations and thus increasing the acidity of species loaded algae leads to leaching of cations pollutants from biosorbent ‎[23]. the sorption process of contaminants is not completely reversible due to diffusion of trace contaminants within oxide particles or into micro pores, incorporation of contaminants into oxides, precipitation, re-adsorption, and chemisorptive adsorption of contaminants onto adsorbent hinders the desorption of contaminants from the spent biomass ‎[24]. a. a. najim and a. a. mohammed / iraqi journal of chemical and petroleum engineering 19,4 (2018) 1-11 7 he et al., ‎[5] used acetonitrile to desorbe methylene blue from nano-crystalline cellulose, the results show that only 18% of mb was desorbed so acetonitrile was not very effective. nevertheless, more than 90% removal after 7 desorption cycles was achieved by using ethanol. the results of adsorptiondesorption processes are shown in fig. 9. fig. 9. five cycle of adsorptiondesorption for mb with two different concentration of hno3 (ph 5, m= 0.7 g, ci= 100 mg/l, 89 µm, speed= 200 rpm, t= 25 ˚c, adsorption time=120 min, and desorption time= 60 min) 3.9. results of pretreatment treated biosorbent generally involves one of two chemical modifications. the first, the biosorbent is interacted with a high concentration of a given ion in aqueous solution consequently, the majority of the sites are occupied by, materials such as calcium, sodium, or potassium. the second is protonation of the biomass with a strong acid such as hcl, so the proton transfers the light metal ions from the binding sites ‎[21]. the most common algal pretreatments are naoh, cacl2, hcl, formaldehyde, and glutaraldehyde ‎[25]. in this review, algae biomass was treated with sodium hydroxide (0.05, 0.1, and 0.5) m, calcium chloride (0.05, 0.1, and 0.5) m, and hydrochloric acid (0.05, 0.1, and 0.5) m to improve the biosorption capacities to methylene blue dye. from fig. 10, the modification of algae biomass by chloride calcium has removal efficiency lower than naoh but better than hcl, the adsorption efficiency decreased with the strength of the acidity. alkali treatment with naoh creates additional basic sites for binding mb cations while acid-treated bleaching earth is a better adsorbent for reactive dyes and acid dyes than for basic dyes ‎[26]. lignocellulosic materials treatment with sodium hydroxide can cause a decrease in crystallinity, a decrease in the degree of polymerization, swelling which leads to an increase in internal surface area, separation of structural linkage between lignin and carbohydrates, increase in the amount of galactouronic acid groups after hydrolysis of o methyl ester groups, removes natural fats and waxes from the cellulose fiber surfaces thus revealing chemically reactive functional groups like – oh, and disruption of the lignin structure, the decrease in copper removal at high naoh concentration, due to the destruction of biomass. for the adsorption of cationic dyes, the surfaces of biomass must be negatively charged. pretreatment by chloride calcium causes calcium binding to alginate that plays a significant role in ion exchange. to increase the contaminants removal efficiency by algae biomass, cacl2 consider a costeffective treatment ‎[25]. although acid modification decrease organic content (lignin, and hemicellulose) of adsorbent and increase porosity, positively charged surfaces with hydrogen ions prevented to extra increase of adsorption ‎[19]. fig. 10. modification of algae biomass using different concentrations of naoh, cacl2, and hcl to remove dyes from solution (ph 5, m= 0.6 g, ci= 50 mg/l, 177 µm, speed= 200 rpm, and time=120 min) 4biosorption isotherm and kinetics models a very essential tool for the investigation of sorption process is sorption isotherms. establish the connection between the amount of adsorbate adsorbed and the equilibrium concentration at a constant temperature by the unit weight of adsorbent. langmuir, freundlich, and temkin isotherm models are widely used to study the sorption process. the model parameters can be construed further, providing understanding of sorption mechanism, surface properties, and an affinity of the sorbent. the langmuir adsorption has been the most widely used adsorption isotherm for the adsorption of a solute from a liquid solution ‎[1]. a. a. najim and a. a. mohammed / iraqi journal of chemical and petroleum engineering 19,4 (2018) 1-11 8 the langmuir model assumes a monolayer adsorption of solutes onto a surface comprised of identical sites with homogeneous biosorption energy ‎[3]. the multilayer sorption and the sorption on heterogeneous surfaces model by using the freundlich equation ‎[7]. temkin isotherm has a factor that obviously taking into the account of adsorbent–adsorbate interactions. the model presumed that the heat of adsorption (function of temperature) of all molecules in the layer, by ignoring the extremely low and large values of concentrations, decreases linearly rather than logarithmic with coverage ‎[27]. the experimental data was analyzed by using non-linear isotherm models. the nonlinear isotherm model parameters were evaluated by using microsoft excel solver software. these models are plotted in fig. 11, tabulated in table 2 and the results are shown in table 3. it can be seen that temkin model has the higher coefficient of determination r 2 . the biosorption kinetics is very important to study the removal of contaminants from wastewater, as it offers valued insights into sorption reaction mechanism and the reaction pathways ‎[28]. pseudosecondorder model better fits the experimental data compared to the pseudofirstorder model, particle diffusion model and elovich model according to higher value of correlation coefficient (r 2 ). this means that biosorption of mb occurs in a monolayer on the surface of adsorbent. the rate limiting step may be chemical sorption according to the second order kinetic model assumption ‎[5]. the results are shown in table 4, figures not shown. table 2. equations for the sorption isotherm and kinetics models model equation used reference langmuir isotherm qe = [27] freundlich isotherm qe = k ce 1/n [27] temkin isotherm qe =bt ln kt ce bt = , [27] pseudo-first-order ln (qe-qt) = ln qe – k1 t [3] pseudo-secondorder ( ) [3] intraparticle diffusion qt = kpt 1/2 + c [4] elovich model qt= ln(αβ)+ ln(t) [29] sum square error (sse) ∑(qe,calc-qe,meas) 2 [30] nonlinear chi square test (x 2 ) ∑ ( ) [30] where, qe is the sorbed dyes molecules on the adsorbent (mg g -1 ), qm is the maximum sorption capacity for monolayer coverage (mg g -1 ), b is the affinity of the binding site (l mg -1 ), and ce is mb concentration in the solution at equilibrium (mg l -1 ). kf = constant indicative of the relative adsorption capacity of the adsorbent (mg/g), 1/n = constant indicative of the intensity of the adsorption. kt is temkin sorption potential (l mg -1 ), and bt & bt are temkin constants. qt is mb uptake capacity (mg/g) at any time t; k1 is the pseudo-first-order rate constant (1/min); and k2 is the pseudo-second-order rate constant (g/mg. min), kp (mg/g min 0.5 ) is the intra-particle diffusion rate constant, c is the value of intercept that gives an idea about the boundary layer thickness. α is the chemisorption rate (mg/g. min) and β is a coefficient in relation with the extension of covered surface and activation energy of chemi-sorption (g/mg). fig. 11. isotherm data of mb adsorption onto algae biomass (ph=5; shaking speed=250 rpm, initial dye concentration =50 mg/l, 89 µm, and 25˚c) table 3. parameters of isotherms model for sorption of mb type of isotherm parameters values langmuir qm (mg/g) 26.65 b (l/mg) 0.0685 r 2 0.9493 rl 0.226 sum square error sse 6.908 x 2 2.1949 freundlich kf 2.388 n 1.5699 r 2 0.9429 sum square error sse 7.794 x 2 2.6931 temkin kt (l/mg) 0.695 bt 5.7149 r 2 0.955 sum square error sse 6.0597 x 2 1.6221 a. a. najim and a. a. mohammed / iraqi journal of chemical and petroleum engineering 19,4 (2018) 1-11 9 table 4. parameters of kinetic models for sorption of mb kinetic models parameters 20 ppm 50 ppm 100 ppm 200 ppm 300 ppm experimental qe 2.8277 6.7134 12.511 22.391 28.063 pseudo first order qe 0.129 0.476 1.447 5.092 6.980 k1 0.0153 0.017 22200 2220 0.0163 r 2 225032 22632 22747 229322 0.8804 pseudo second order qe 2.827 6.725 12.56 22.57 28.17 k2 0.558 22037 22230 22200 8e-3 r 2 0.9999 0 0.9999 22777 0.9979 intra-particle diffusion c 2.65 6.102 11.02 17.35 21.13 kp 222022 22230 22000 2217 0.51 r 2 22542 22660 22737 227724 0.9863 elovich model α 2.2e21 1.45e14 124.58e9 428679.8 271798.3 β 20.24 5.875 2.531 228118 0.631 r 2 226544 227471 227711 227411 0.9207 5conclusions the results indicated that algae biomass could be used as an efficient biosorbent material for the removal of methylene blue dye molecules from aqueous solution. the higher percentage achieved (98.97%) at ph 5, 0.7 g /100ml biomass dosage, 250 rpm shaking speed, 89 µm particle size, 20 ppm initial dye concentration, and t=25˚c for 120 min. temkin model fitted the experimental data very well compared to langmuir and freundlich models, while the kinetic study well fitted by pseudo second order with very high r 2 . the thermodynamic parameters calculated (γg°, γh° and γs°) showed that the biosorption of mb were feasible, spontaneous and endothermic at temperature ranges of 293-313 k. results show that adsorptiondesorption process lasts for five cycle before losing its efficiency and the recovery efficiency increased from 50.7% to 80.52% when the concentration of nitric acid increased from 0.05 to 0.1m. treated algae with naoh show the highest removal efficiency compared to cacl2 and hcl in all its concentrations. nomenclature b: affinity of the binding site, l/ mg, bt & bt: temkin constants c: value of intercept that gives an idea about the boundary layer thickness, mg/g cad: adsorbed concentration, mg/l ce: concentration at equilibrium, mg/l ci: initial concentration, mg/l ea: activation energy, kj/ mole ec: electrical conductivity, µs/cm γg: gibbs free energy, kj/mole γh: enthalpy change, kj/mole k1: pseudo-first-order rate constant, 1/min k2: pseudo-second-order rate constant, g/mg. min kc: equilibrium constant kf: constant indicative of the relative adsorption capacity of the adsorbent, mg/g kp: intra-particle diffusion rate constant, mg/g min 0.5 kt: temkin sorption potential, l/ mg m: mass of adsorbent, g mad: total adsorbed, mg/l md: desorbed concentration, mg/l 1/n: constant indicative of the intensity of the adsorption qe: sorbed dyes molecules on the adsorbent, mg/ g qm: the maximum sorption capacity for monolayer coverage, mg/ g qt: mb uptake capacity, mg/g at any time t r: universal gas constant s*: sticking probability γs: entropy change, j/k. mole t: temperature, k v: volume, l θ: surface coverage α: chemisorption rate, mg/g. min β: coefficient in relation with the extension of covered surface and activation energy of chemisorption (g/mg) references [1] o. gulnaz, a. sahmurova, and s. kama. ''removal of reactive red 198 from aqueous solution by potamogeton crispus''. chemical engineering journal, 174(2-3), 579-585, 2011. [2] c. c. ambasana. ''microbial degradation of recalcitrant compound". doctoral dissertation, saurashtra university, 2006. [3] r. k. gautam, a. mudhoo, and m. c. chattopadhyaya. "kinetic, equilibrium, thermodynamic studies and spectroscopic analysis of alizarin red s removal by mustard husk". journal of environmental chemical engineering, vol. 1, pp.1283-1291, 2013. [4] h. d. bouras, a. r. yeddou, n. bouras, d. hellel, m. d. holtz, n. sabaou, ... and b. nadjemi. "biosorption of congo red dye by aspergillus carbonarius m333 and penicillium glabrum pg1: kinetics, equilibrium and thermodynamic studies". journal of the taiwan institute of chemical engineers, vol. 80, pp. 915-923, 2017. [5] x. he, k. b. male, p. n. nesterenko, d. brabazon, b. paull, , and j. h. luong. "adsorption and desorption of methylene blue on porous carbon monoliths and nanocrystalline cellulose". acs applied materials & interfaces, vol. 5, pp. 8796-8804, 2013. https://www.sciencedirect.com/science/article/pii/s1385894711011193 https://www.sciencedirect.com/science/article/pii/s1385894711011193 https://www.sciencedirect.com/science/article/pii/s1385894711011193 https://www.sciencedirect.com/science/article/pii/s1385894711011193 http://etheses.saurashtrauniversity.edu/905/1/ambasana_cc_thesis_microbiology.pdf http://etheses.saurashtrauniversity.edu/905/1/ambasana_cc_thesis_microbiology.pdf http://etheses.saurashtrauniversity.edu/905/1/ambasana_cc_thesis_microbiology.pdf https://www.sciencedirect.com/science/article/pii/s2213343713001863 https://www.sciencedirect.com/science/article/pii/s2213343713001863 https://www.sciencedirect.com/science/article/pii/s2213343713001863 https://www.sciencedirect.com/science/article/pii/s2213343713001863 https://www.sciencedirect.com/science/article/pii/s2213343713001863 https://www.sciencedirect.com/science/article/pii/s2213343713001863 https://www.sciencedirect.com/science/article/pii/s1876107017304054 https://www.sciencedirect.com/science/article/pii/s1876107017304054 https://www.sciencedirect.com/science/article/pii/s1876107017304054 https://www.sciencedirect.com/science/article/pii/s1876107017304054 https://www.sciencedirect.com/science/article/pii/s1876107017304054 https://www.sciencedirect.com/science/article/pii/s1876107017304054 https://www.sciencedirect.com/science/article/pii/s1876107017304054 https://pubs.acs.org/doi/abs/10.1021/am403222u https://pubs.acs.org/doi/abs/10.1021/am403222u https://pubs.acs.org/doi/abs/10.1021/am403222u https://pubs.acs.org/doi/abs/10.1021/am403222u https://pubs.acs.org/doi/abs/10.1021/am403222u a. a. najim and a. a. mohammed / iraqi journal of chemical and petroleum engineering 19,4 (2018) 1-11 01 [6] b. h. hameed, a. m. din, and a. l. ahmad. "adsorption of methylene blue onto bamboo-based activated carbon: kinetics and equilibrium studies". journal of hazardous materials, vol. 141, pp. 819-825, 2007. [7] m. rafatullah, o. sulaiman, r. hashim and a. ahmad. "adsorption of methylene blue on low-cost adsorbents: a review". journal of hazardous materials, vol. 177, pp. 70-80, 2010. [8] o. gulnaz, a. sahmurova and s. kama."removal of reactive red 198 from aqueous solution by potamogeton crispus". chemical engineering journal, vol. 174, pp. 579-585, 2011. [9] l. yu, and y. m. luo. "the adsorption mechanism of anionic and cationic dyes by jerusalem artichoke stalk-based mesoporous activated carbon". journal of environmental chemical engineering, vol. 2, pp. 220-229, 2014. [10] a. e. pirbazari, e. saberikhah, m. badrouh, and m. s. emami. "alkali treated foumanat tea waste as an efficient adsorbent for methylene blue adsorption from aqueous solution". water resources and industry, vol. 6, pp. 64-80, 2014. [11] s. chowdhury, m. yasin, m. t. uddin, and m. a. islam. "batch and continuous (fixed bed column) adsorption of methylene blue by rubber leaf powder". international journal of integrated sciences & technology, vol. 2, pp. 24-28, 2016. [12] e. rubin, p. rodriguez, r. herrero, j. cremades, i. barbara, and m. e. sastre de vicente. "removal of methylene blue from aqueous solutions using as biosorbent sargassum muticum: an invasive macroalga in europe". journal of chemical technology & biotechnology: international research in process, environmental & clean technology, vol. 80, pp. 291-298, 2005. [13] m. a. hossain, h. h. ngo, w. s. guo, and t. setiadi. "adsorption and desorption of copper (ii) ions onto garden grass". bioresource technology, vol. 121, pp. 386-395, 2012. [14] r. maurya, t. ghosh, c. paliwal, a. shrivastav, k. chokshi, i. pancha,... and s. mishra. "biosorption of methylene blue by de-oiled algal biomass: equilibrium, kinetics and artificial neural network modelling". plos one, vol. 9, pp. e109545, 2014. [15] h. shao, y. li, l. zheng, t. chen, and j. liu. "removal of methylene blue by chemically modified defatted brown algae laminaria japonica". journal of the taiwan institute of chemical engineers, vol. 80, pp. 525-532, 2017. [16] g. annadurai, r. s. juang, and d. j. lee. "use of cellulose-based wastes for adsorption of dyes from aqueous solutions". journal of hazardous materials, vol. 92, pp. 263-274, 2002. [17] s. r. pilli, v. v. goud, and k. mohanty. "biosorption of cr (vi) on immobilized hydrilla verticillata in a continuous up-flow packed bed: prediction of kinetic parameters and breakthrough curves". desalination and water treatment, vol. 50, pp. 115-124, 2012. [18] d. bulgariu, and l. bulgariu. "potential use of alkaline treated algae waste biomass as sustainable biosorbent for clean recovery of cadmium (ii) from aqueous media: batch and column studies". journal of cleaner production, vol. 112, pp. 4525-4533, 2016. [19] m. j. puchana-rosero, e. c. lima, s. ortizmonsalve, b. mella, d. da costa, e. poll, and m. gutterres. "fungal biomass as biosorbent for the removal of acid blue 161 dye in aqueous solution". environmental science and pollution research, vol. 24, pp. 4200-4209, 2017. [20] a. h. sulaymon, a. a. mohammed, and t. j. al-musawi. "comparative study of removal of cadmium (ii) and chromium (iii) ions from aqueous solution using low-cost biosorbent". international journal of chemical reactor engineering, vol. 12, pp. 477-486, 2014. [21] t. a. davis, b. volesky, and a. mucci, "a review of the biochemistry of heavy metal biosorption by brown algae". water research, vol. 37, pp. 43114330, 2003. [22] n. feng, x. guo, s. liang, y. zhu, and j. liu. "biosorption of heavy metals from aqueous solutions by chemically modified orange peel". journal of hazardous materials, vol. 185, pp. 49-54, 2011. [23] z. kariuki, j. kiptoo, and d. onyancha. "biosorption studies of lead and copper using rogers mushroom biomass ‘lepiota hystrix’". south african journal of chemical engineering, vol. 23,pp. 62-70, 2017. [24] a. g. el-said, n. a. badawy, and s. e. garamon. "adsorption of cadmium (ii) and mercury (ii) onto natural adsorbent rice husk ash (rha) from aqueous solutions: study in single and binary system". j am sci, vol. 6, pp. 400-409, 2010. [25] a. k. zeraatkar, h. ahmadzadeh, a. f. talebi, n. r. moheimani, and m. p. mchenry. "potential use of algae for heavy metal bioremediation, a critical review". journal of environmental management, vol. 181, pp. 817-831, 2016. [26] g. hisarli. "the effects of acid and alkali modification on the adsorption performance of fuller's earth for basic dye". journal of colloid and interface science, vol. 281, pp. 18-26, 2005. [27] a. o. dada, a. p. olalekan. a. m. olatunya, and o. dada. "langmuir, freundlich, temkin and dubinin– radushkevich isotherms studies of equilibrium sorption of zn2+ unto phosphoric acid modified rice husk". iosr journal of applied chemistry, vol. 3, pp. 38-45, 2012. [28] a. h. sulaymon, a. a. mohammed, and t. j. almusawi. "removal of lead, cadmium, copper, and arsenic ions using biosorption: equilibrium and kinetic studies". desalination and water treatment, vol. 51, pp. 4424-4434, 2013. [29] k. d. belaid, s. kacha, m. kameche, and z. derriche. "adsorption kinetics of some textile dyes onto granular activated carbon". journal of environmental chemical engineering, vol. 1, pp. 496-503, 2013. [30] k. y. foo, and b. h. hameed. insights into the modeling of adsorption isotherm systems. chemical engineering journal, vol. 156, pp. 2-10, 2010. https://www.sciencedirect.com/science/article/pii/s0304389406008739 https://www.sciencedirect.com/science/article/pii/s0304389406008739 https://www.sciencedirect.com/science/article/pii/s0304389406008739 https://www.sciencedirect.com/science/article/pii/s0304389406008739 https://www.sciencedirect.com/science/article/pii/s0304389406008739 https://www.sciencedirect.com/science/article/pii/s0304389409020354 https://www.sciencedirect.com/science/article/pii/s0304389409020354 https://www.sciencedirect.com/science/article/pii/s0304389409020354 https://www.sciencedirect.com/science/article/pii/s0304389409020354 https://www.sciencedirect.com/science/article/pii/s1385894711011193 https://www.sciencedirect.com/science/article/pii/s1385894711011193 https://www.sciencedirect.com/science/article/pii/s1385894711011193 https://www.sciencedirect.com/science/article/pii/s1385894711011193 https://www.sciencedirect.com/science/article/pii/s2213343713002637 https://www.sciencedirect.com/science/article/pii/s2213343713002637 https://www.sciencedirect.com/science/article/pii/s2213343713002637 https://www.sciencedirect.com/science/article/pii/s2213343713002637 https://www.sciencedirect.com/science/article/pii/s2213343713002637 https://www.sciencedirect.com/science/article/pii/s2212371714000195 https://www.sciencedirect.com/science/article/pii/s2212371714000195 https://www.sciencedirect.com/science/article/pii/s2212371714000195 https://www.sciencedirect.com/science/article/pii/s2212371714000195 https://www.sciencedirect.com/science/article/pii/s2212371714000195 http://www.cuet.ac.bd/ijist/files/2016/paper%2058.pdf http://www.cuet.ac.bd/ijist/files/2016/paper%2058.pdf http://www.cuet.ac.bd/ijist/files/2016/paper%2058.pdf http://www.cuet.ac.bd/ijist/files/2016/paper%2058.pdf http://www.cuet.ac.bd/ijist/files/2016/paper%2058.pdf https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.1192 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.1192 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.1192 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.1192 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.1192 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.1192 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.1192 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.1192 https://www.tib.eu/en/search/id/blse%3arn317768616/adsorption-and-desorption-of-copper-ii-ions-onto/ https://www.tib.eu/en/search/id/blse%3arn317768616/adsorption-and-desorption-of-copper-ii-ions-onto/ https://www.tib.eu/en/search/id/blse%3arn317768616/adsorption-and-desorption-of-copper-ii-ions-onto/ https://www.tib.eu/en/search/id/blse%3arn317768616/adsorption-and-desorption-of-copper-ii-ions-onto/ https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0109545 https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0109545 https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0109545 https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0109545 https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0109545 https://www.sciencedirect.com/science/article/pii/s1876107017304261 https://www.sciencedirect.com/science/article/pii/s1876107017304261 https://www.sciencedirect.com/science/article/pii/s1876107017304261 https://www.sciencedirect.com/science/article/pii/s1876107017304261 https://www.sciencedirect.com/science/article/pii/s1876107017304261 https://www.sciencedirect.com/science/article/pii/s0304389402000171 https://www.sciencedirect.com/science/article/pii/s0304389402000171 https://www.sciencedirect.com/science/article/pii/s0304389402000171 https://www.sciencedirect.com/science/article/pii/s0304389402000171 https://www.tandfonline.com/doi/abs/10.1080/19443994.2012.708555 https://www.tandfonline.com/doi/abs/10.1080/19443994.2012.708555 https://www.tandfonline.com/doi/abs/10.1080/19443994.2012.708555 https://www.tandfonline.com/doi/abs/10.1080/19443994.2012.708555 https://www.tandfonline.com/doi/abs/10.1080/19443994.2012.708555 https://www.tandfonline.com/doi/abs/10.1080/19443994.2012.708555 https://www.sciencedirect.com/science/article/pii/s0959652615007039 https://www.sciencedirect.com/science/article/pii/s0959652615007039 https://www.sciencedirect.com/science/article/pii/s0959652615007039 https://www.sciencedirect.com/science/article/pii/s0959652615007039 https://www.sciencedirect.com/science/article/pii/s0959652615007039 https://link.springer.com/article/10.1007/s11356-016-8153-4 https://link.springer.com/article/10.1007/s11356-016-8153-4 https://link.springer.com/article/10.1007/s11356-016-8153-4 https://link.springer.com/article/10.1007/s11356-016-8153-4 https://link.springer.com/article/10.1007/s11356-016-8153-4 https://link.springer.com/article/10.1007/s11356-016-8153-4 https://www.degruyter.com/view/j/ijcre.2014.12.issue-1/ijcre-2014-0024/ijcre-2014-0024.xml https://www.degruyter.com/view/j/ijcre.2014.12.issue-1/ijcre-2014-0024/ijcre-2014-0024.xml https://www.degruyter.com/view/j/ijcre.2014.12.issue-1/ijcre-2014-0024/ijcre-2014-0024.xml https://www.degruyter.com/view/j/ijcre.2014.12.issue-1/ijcre-2014-0024/ijcre-2014-0024.xml https://www.degruyter.com/view/j/ijcre.2014.12.issue-1/ijcre-2014-0024/ijcre-2014-0024.xml https://www.degruyter.com/view/j/ijcre.2014.12.issue-1/ijcre-2014-0024/ijcre-2014-0024.xml https://www.sciencedirect.com/science/article/abs/pii/s0043135403002938 https://www.sciencedirect.com/science/article/abs/pii/s0043135403002938 https://www.sciencedirect.com/science/article/abs/pii/s0043135403002938 https://www.sciencedirect.com/science/article/abs/pii/s0043135403002938 https://www.sciencedirect.com/science/article/pii/s0304389410011477 https://www.sciencedirect.com/science/article/pii/s0304389410011477 https://www.sciencedirect.com/science/article/pii/s0304389410011477 https://www.sciencedirect.com/science/article/pii/s0304389410011477 https://www.sciencedirect.com/science/article/pii/s1026918516300063 https://www.sciencedirect.com/science/article/pii/s1026918516300063 https://www.sciencedirect.com/science/article/pii/s1026918516300063 https://www.sciencedirect.com/science/article/pii/s1026918516300063 https://www.sciencedirect.com/science/article/pii/s1026918516300063 http://www.jofamericanscience.org/journals/am-sci/am0612/47_3316am0612_400_409.pdf http://www.jofamericanscience.org/journals/am-sci/am0612/47_3316am0612_400_409.pdf http://www.jofamericanscience.org/journals/am-sci/am0612/47_3316am0612_400_409.pdf http://www.jofamericanscience.org/journals/am-sci/am0612/47_3316am0612_400_409.pdf http://www.jofamericanscience.org/journals/am-sci/am0612/47_3316am0612_400_409.pdf https://www.sciencedirect.com/science/article/pii/s030147971630425x https://www.sciencedirect.com/science/article/pii/s030147971630425x https://www.sciencedirect.com/science/article/pii/s030147971630425x https://www.sciencedirect.com/science/article/pii/s030147971630425x https://www.sciencedirect.com/science/article/pii/s030147971630425x https://www.sciencedirect.com/science/article/pii/s0021979704008021 https://www.sciencedirect.com/science/article/pii/s0021979704008021 https://www.sciencedirect.com/science/article/pii/s0021979704008021 https://www.sciencedirect.com/science/article/pii/s0021979704008021 https://www.researchgate.net/profile/qhatan_yousif/post/in_langmuir_isotherm-ce_qe_vs_ce_how_do_i_find_ce_ce_is_eqlbm_conc_mg_l_of_adsorbate_to_plot_graph_we_need_many_values_of_ce_how_to_find_it/attachment/59d6583779197b80779ae3a7/as:537623073693697@1505190737813/download/adsorption++%282%29.pdf https://www.researchgate.net/profile/qhatan_yousif/post/in_langmuir_isotherm-ce_qe_vs_ce_how_do_i_find_ce_ce_is_eqlbm_conc_mg_l_of_adsorbate_to_plot_graph_we_need_many_values_of_ce_how_to_find_it/attachment/59d6583779197b80779ae3a7/as:537623073693697@1505190737813/download/adsorption++%282%29.pdf https://www.researchgate.net/profile/qhatan_yousif/post/in_langmuir_isotherm-ce_qe_vs_ce_how_do_i_find_ce_ce_is_eqlbm_conc_mg_l_of_adsorbate_to_plot_graph_we_need_many_values_of_ce_how_to_find_it/attachment/59d6583779197b80779ae3a7/as:537623073693697@1505190737813/download/adsorption++%282%29.pdf https://www.researchgate.net/profile/qhatan_yousif/post/in_langmuir_isotherm-ce_qe_vs_ce_how_do_i_find_ce_ce_is_eqlbm_conc_mg_l_of_adsorbate_to_plot_graph_we_need_many_values_of_ce_how_to_find_it/attachment/59d6583779197b80779ae3a7/as:537623073693697@1505190737813/download/adsorption++%282%29.pdf https://www.researchgate.net/profile/qhatan_yousif/post/in_langmuir_isotherm-ce_qe_vs_ce_how_do_i_find_ce_ce_is_eqlbm_conc_mg_l_of_adsorbate_to_plot_graph_we_need_many_values_of_ce_how_to_find_it/attachment/59d6583779197b80779ae3a7/as:537623073693697@1505190737813/download/adsorption++%282%29.pdf https://www.tandfonline.com/doi/abs/10.1080/19443994.2013.769695 https://www.tandfonline.com/doi/abs/10.1080/19443994.2013.769695 https://www.tandfonline.com/doi/abs/10.1080/19443994.2013.769695 https://www.tandfonline.com/doi/abs/10.1080/19443994.2013.769695 https://www.tandfonline.com/doi/abs/10.1080/19443994.2013.769695 https://www.sciencedirect.com/science/article/pii/s221334371300047x https://www.sciencedirect.com/science/article/pii/s221334371300047x https://www.sciencedirect.com/science/article/pii/s221334371300047x https://www.sciencedirect.com/science/article/pii/s221334371300047x https://www.sciencedirect.com/science/article/pii/s1385894709006147 https://www.sciencedirect.com/science/article/pii/s1385894709006147 https://www.sciencedirect.com/science/article/pii/s1385894709006147 a. a. najim and a. a. mohammed / iraqi journal of chemical and petroleum engineering 19,4 (2018) 1-11 00 المائي باستخدام الطحالب المختلطةامتزاز صبغه المثيل الزرقاء من المحلول الخالصة ( chlorophyte، و chrysophyta ،cyanophytaتم استخدام خميط من الكتمة الحيوية لمطحالب ) جم / 2-0.2( ، كمية المادة المازة )8-1(. تم دراسة تأثير األس الهيدروجيني )mbالزاله )الصبغه الزرقاء ، -20ميكرو متر( ، درجة الحرارة ) 88-1304( ، حجم الجسيمات )300-100)مل( ، سرعة التحريك 100 40˚c( تركيز الصبغة األولي ، )ممغم / لتر( ، وتمت دراسة امتصاص االمتصاص لتقييم آلية 30020 من أجل cacl2امتصاص صبغة الطحالب. وقد تم تجربة مختمف المعالجات، القمويات ، والبروتونات ، و االمتزاز وكذلك استقرار الكتمة الحيوية لمطحالب. تم تحميل بيانات متساوي الحرارة باستخدام نماذج تعزيز قدرة langmuir وfreundlich وtemkin ممغ / غم عند 26.65. كانت السعة القصوى المتصاص األصباغ ممغم / 50ية ، و درجة مئو 25ميكرو متر ، و 88دورة في الدقيقة ، و 250، و 5الرقم الهيدروجيني = لتر كتركيز أولي. تم اختبار أربعة نماذج حركية ، من الدرجة األولى الزائفة ، والنظام الثاني الزائف ، وانتشار ( ، كانت البيانات األفضل x2و ssr. مع األخذ بعين االعتبار تحميل )elovichداخل الجزبئة والنموذج نتائج ان البيانات تخضع لمودبل الزائف من الدرجة الثانية. . اضهرت الtemkin isothermمالئمة لنموذج *( عند درجات حرارة تتراوح بين sو γg0 ،γh0 ،γs0 ،eaأظهرت المعممات الديناميكية الحرارية ) 283-313 k أن اإلمتصاص هو تفاعل ماص لمحرارة ، وتفاعل تمقائي ، ودرجة حرارة أعمى لمحل تدعم إزالة االسترجاع تستمر -الصبغة الزرقاء باالمتزاز عمى الكتمة الحيوية لمطحالب. تظهر النتائج أن عممية االمتزاز ٪. 80.52لمدة خمس دورات قبل أن تفقد كفاءتها وزيادة كفاءة االسترداد إلى available online at https://ijcpe.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.19 no.1 (march 2018) 21 – 27 issn: 1997-4884 corresponding authors: hayder m. abbas, email: hayder_mahdi@yahoo.com, sarmad t. najim, email: dr_sarmadalani@yahoo.com iraqi journal of chemical and petroleum engineering experimental study for the influence of operating parameters on copper electrorefining process hayder m. abbas and sarmad t. najim chemical engineering department ــ college of engineering ــ al-nahrain university abstract copper electrodeposition by electrorefining process in acidic sulfate media contains 40 g/l of cupric ions and 160 g/l of sulfuric acid was achieved to study the influence of the operating parameters on cathode purity, surface morphology, deposition rate, current efficiency and power consumption. these operating parameters and there ranges are: current density 200, 300 and 400 a/m 2 , electrolyte temperature 35, 50 and 65 o c, electrodes spacing 15, 30 and 45 mm and electrolyte residence time 6, 4 and 2 h were utilized. xrf, sem and edx analyses were attained to clarify the properties of the produced cathode. keywords: copper electrorefining process, purity, morphology, deposition rate, current efficiency, power consumption, electrolyte residence time. 1introduction metals are absolutely necessary to reinforce economic development and the work of modern civilization. a metal demand is growing beside the worldwide inhabitance increases and metals are utilized in a larger range of industries, especially connected with the spread of novel technologies [1]. copper market is one of the biggest of all metals backwards iron and aluminum. copper acting a considerable role in the manufacturing production because it is simple to work with, effective electricity and heat conductivity and it has a good corrosion resistance [2]. pyrometallurgical process was achieved 80% of global copper production [3]. in the electrorefining cell the casting anodes were dissolved in the electrolyte solution and the electrical current was applied to deposit the copper as a pure metal on the cathode [4]. additional benefit was gained from process by the recovery of cells slime to produce valuable metals like selenium, gold, tellurium and silver [3]. the continuously huge demand leads to improve the copper electrorefining process, for example in the last years in order to raise the production rate, the current density was raised to high values with keeping of copper purity level, also improvement was employed by modified the design of the electrorefining cell, the electrolyte movement control at the electrodes surface, optimized the quantities of the additive regents and advanced of substitute additives [5]. the electrorefining process occurs in a cell in which the comparatively impure casting anodes are hanging in an acidic electrolyte every other among soft pure copper starter sheets which will come to be the cathodes. on applied copper electrorefining processes, acidic electrolyte is used exclusively, the usage of acidic electrolyte for the reason that power and chemicals costs are low and on account of the control of these solutions are simple and forward straight [6,7]. anode must be connecting to the positive pole of the electrical supply, whereas the pure copper starter sheet must be connecting to the negative pole of the electrical supply. when the electrical supply is turn on, the atoms of copper will lose electrons and diffused to the cathode through the electrolyte, then it will deposit as pure copper, for every ion deposited onto the cathode, else ion passes in the electrolyte from the anode. finally the anode is spent and its impurities either stay dissolved in the electrolyte or drops to the bottom of the cell creating the slime, by this process pure copper cathode is yield and other expensive metals existing in the anode like platinum, silver, gold, or palladium, can be recovered from the slime [6]. the major electrical factor that can influence the purity of yield cathode is the current density. the universal direction in copper electrorefining process is to work with highly level of current densities; this decreases the size of plant for a new system and growths the production rate for old plant [8].the electrolyte heating is costly but its valuable influence in copper electrorefining process [9]. electrodes spacing play an important role in the copper electrorefining process, so it has to be set to improve the specifications of produced cathodes [10]. the rate of circulation must realize a minimal change of cell electrolyte every 4-6 h. h. m. abbas and s. t. najim./ iraqi journal of chemical and petroleum engineering91,9 (2018) 21-27 22 a steady slow electrolyte movement in the cell is needful for increase the mass transport, settle down of anode slimes at the cell bottom, make a good control to electrolyte temperature and carry off the dissolving contaminations from the cell [11]. the main objectives of present work are: design, construct and install of a laboratory electrorefining cell, study the influence of several operating parameters on cathode purity, surface morphology, deposition rate, current efficiency and power consumption, also optimizing the operational conditions of process by obtain the optimum operating parameters that provide the finest quality and quantity of the produced copper. 2theory the fundamentals of electrorefining process based on electrochemical kinetics philosophies [12]. like every electrodeposition processes, the electrodeposition of copper is an electrolytic process that is created from electrochemical reduction reaction on cathode, so the reducing copper produce is deposited on the cathode surface. if other (undesired) reactions are do not happening in the same time, at that point it can assume that the reaction at cathode in the electrolyte solution is only the desired copper reduction. (1) the copper electrodeposition process contains many steps. principally the steps are movements of reactive ions from electrolyte to the surface of cathode, adsorption of the ions, transfer of the charge at the cathode surface, cathode surface diffusion and metal deposition, nucleation occurs first and then developing into crystal structure [13,14]. copper electrodeposition process is a complex heterogeneous system, all electrochemical events take place in three thin layers whose properties dissimilar from those of the bulk electrolyte. the helmholtz double layer consist of the inner and outer helmholtz layer, the double layer consist of specially adsorbed cations and molecules of water. proceeding from the helmholtz double layer in the direction of the bulk electrolyte are the diffusion layer followed by the hydrodynamic layer. inside the diffusion layer, the cations concentration variations from that of the electrode surface to that of the bulk electrolyte. the diffusion layer does not change position but with increasing the flow rate of bulk electrolyte, its thickness will reduced to permit greater rates of the electrochemical reaction, theoretically the thickness of the diffusion layer is inversely proportional to the square root of the flow rate. the hydrodynamic layer or prandtl layer has the similar composition like the bulk electrolyte, but the movement of the electrolyte decreases from that of the bulk electrolyte to the motionless diffusion layer [15]. the theoretical deposit cathode weight wtheo. can be calculated from faraday‟s law; (g) = (2) where i is the applied current, t is deposition time, is copper atomic weight, z is electron valency and f is faraday‟s constant. the actual cathode deposition rate acdr can be calculated by divided the actual deposit weight of cathode over the deposition time and the deposition area [16]. (3) the current efficiency ce% represented the proportion of current transient over an electrolytic cell in order to achieve the wanted electrochemical reaction. it can be calculated by the following equation [8]: (4) however, there is a continuous need to minimizing power consumption by reducing cell voltage, by increasing current efficiency and keeping good electrical connections during the electrorefining process [17]. the power consumption can be calculated from the following equation: (5) where vcell is the cell voltage. 3experimental work two parts consist of 33 experiment were achieved. electrolyte was prepared by using annular sulfuric acid supplied by baker company with specific gravity 1.84 and purity 97%, diluted with distilled water to obtain an electrolyte solution of 160 g/l, then 160 g of copper sulfate pentahydrate supplied by shanghai mintchem company with purity 98%, added to one liter of this electrolyte solution and stirred to gain 40 g/l of cupric ions concentration. figure1. represents the experimental apparatus were utilized in the present work. a rectangle lab scale cell constructed from pyrex glass with active volume of 720 ml was used. the starting cathode sheet was made of pure copper with total area of (100*80*mm) and immersed area of (70*70 mm) with thickness 0.6 mm. anode was used with a copper content of (98.48 % wt. cu) and with total area of (100*80*mm) and immersed area of (75*80 mm) with thickness 6.5 mm. before every single experiment, three steps was done for electrodes preparation, the first step was polishing with (220, 320 and 800) grades of sandpaper in order to eliminate film oxides & any contaminations on the surface, in the second step ethanol was used to remove any grease, in the third step electrodes were immersed in (1/5) volume ratio of sulphuric acid to distilled water mixture, after finishing of each steps the electrodes were h. m. abbas and s. t. najim./ iraqi journal of chemical and petroleum engineering91,9 (2018) 21-27 22 washed by distilled water and dried by gauze. the electrodes saved inside the desiccator over-night before utilized. the electrical circuit contains a digital dc power supply connected with the cell and ammeter in series, while the voltmeter connected in parallel with the cathode and the anode respectively. fig. 1. schematic diagram of experimental apparatus: 1 anode, 2cathode, 3electrolyte input line, 4 electrolyte output line, 5dosing pump, 6water bath, 7 power supply, 8voltmeter, 9ammeter, 10stand, 11 electrical wires, 12thermometer. experimental program in part one was to study the effect of current density (cd) 200, 300 and 400 a/m 2 , electrolyte temperature (t) 35, 50 and 65 o c and electrodes spacing (s) 15, 30 and 45 mm with stationary electrolyte on cathode purity, surface morphology, deposition rate, current efficiency and power consumption and obtained the optimum operating parameters, while the second part deals with studying the effect of electrolyte residence time ert 6, 4 and 2 h on optimum operating parameters obtained from part one. tables 1 and 2 are summarizing the operating parameters of parts 1 and 2. table 1. summary of the operating parameters for part one exp no. cd a/m 2 t o c s mm exp no. cd a/m 2 t o c s mm 1 200 35 15 15 300 50 45 2 200 35 30 16 300 65 15 3 200 35 45 17 300 65 30 4 200 50 15 18 300 65 45 5 200 50 30 19 400 35 15 6 200 50 45 20 400 35 30 7 200 65 15 21 400 35 45 8 200 65 30 22 400 50 15 9 200 65 45 23 400 50 30 10 300 35 15 24 400 50 45 11 300 35 30 25 400 65 15 12 300 35 45 26 400 65 30 13 300 50 15 27 400 65 45 14 300 50 30 table 2. summary of the operating parameters in part two exp. no. cd a/m 2 t o c s mm ert h 28 200 65 15 6 29 200 65 15 4 30 200 65 15 2 31 200 65 30 6 32 200 65 30 4 33 200 65 30 2 4results and discussion 4.1. part one table 3 shows the actual cathode deposition rate, current efficiency and power consumption values resulted from this part. a. effect of the current density (cd) increase the current density would exceedingly decrease the cathode purity, the maximum copper purity of 99.59% cu was obtained in exp. no. 7. it can be clarified that by increasing the current density leads to increase the anode dissolution rate which increased the amount of impurities, that gives more chances to deposit of the impurities on the cathode surface caused the deterioration of cathode purity. table 3. acdr, ce% and p of part one exp. no. acdr g / h.m2 ce % p kwh/kg 1 232.9 98.23 0.6536 2 232.5 98.04 0.8562 3 231.4 97.61 1.0607 4 234.1 98.73 0.6045 5 233.6 98.52 0.8194 6 232.6 98.11 0.9874 7 234.9 99.07 0.5425 8 234.3 98.82 0.6064 9 233.7 98.56 0.7798 10 346.1 97.30 0.8944 11 345.1 97.03 0.9814 12 344.1 96.74 1.1377 13 346.7 97.49 0.7340 14 346.1 97.32 0.8576 15 345.5 97.15 1.0227 16 348.0 97.84 0.6174 17 347.4 97.68 0.8073 18 346.2 97.33 0.9639 19 448.0 94.47 1.1156 20 446.9 94.25 1.1919 21 445.8 94.01 1.2475 22 450.9 95.09 0.9533 23 449.2 94.72 1.0004 24 446.8 94.23 1.0817 25 452.5 95.43 0.6927 26 451.5 95.21 0.8526 27 450.0 94.90 1.0126 h. m. abbas and s. t. najim./ iraqi journal of chemical and petroleum engineering91,9 (2018) 21-27 22 as the current density increase the cathode surface morphology extremely decline and becomes rougher, best surface morphology was obtained in exp. no. 7 as shown in fig.2 (a, b and c), the probable cause that by increasing current density would promote the nucleation on active sites, and that would leads to creation of a higher number of small grains which gradually agglomerate in higher local current density active sites at the surface of cathode formed a unequal copper deposition thickness. it can be seen from fig. 3 that the ce% decreases with increase current density, the maximum ce% obtained in exp. no. 7, the possible explanation is that by increasing current density the charged spices will increases also and that will increase the probability to initiate side electrochemical reactions. a positive influence of the current density increasing on acdr, the desired maximum acdr obtained in exp. no. 25, it can be interpreting that increase the surface of cathode formed a unequal copper deposition thickness. fig. 2. sem micrographs show surface morphology effecting by (a, b and c) current density exp. no. 7, 16 and 25 respectively, (d, e and f) electrolyte temperature exp. no. 7, 4 and 1 respectively, (g, h and i) electrodes spacing exp. no. 7, 8 and 9 respectively it can be seen from fig. 3 that the ce% decreases with increase current density, the maximum ce% obtained in exp. no. 7, the possible explanation is that by increasing current density the charged spices will increases also and that will increase the probability to initiate side electrochemical reactions. a positive influence of the current density increasing on acdr, the desired maximum acdr obtained in exp. no. 25, it can be interpreting that increase of current density would increase intensity of the generating electric field and that would increase the migration rate of the charged spices, beside that the diffusion rate would increasing due to increases of cupric ions concentration on the adjacent anode layer and decrease of cupric ions concentration on the adjacent cathode layer and that is in a good agreement with najim [18]. 100 200 300 400 500 current density (a/m2) 94 95 96 97 98 99 100 c e % t ( 65 oc ) s (15 mm) s (30 mm) s (45 mm) fig. 3. effect of current density on current efficiency with constant t 65 o c and s 15, 30 and 45 mm the increasing of the current density caused a significant increase for power consumption, the desired minimum p value is 0.5425 kw.h/kg which was obtained in exp. no. 7, it can clarified that increase of current density leads to increase the cell voltage that causing increase of the power consumption. b. effect of the electrolyte temperature as electrolyte temperature increases cathode purity will increase. it can be clarified that increase of electrolyte temperature leads to decrease its density and viscosity, this impact make the bigger contamination particles have a greater settling velocity and will be precipitate to the cell bottom more quickly, so be less probability to deposited on the cathode surface, while the finer contamination particles have a lesser settling velocity will be suspended in the electrolyte, so be more probability to deposited on the cathode surface. fig. 2(d, e and f) shows that when electrolyte temperature decreases cathode surface morphology declined and become rougher. the possible explanation that decrease electrolyte temperature will decrease the electrical conductivity of electrolyte and that will hinder the current density distribution in the cell causing unequal spreading of deposit grains over cathode surface producing a rougher deposit. the increasing of the electrolyte temperature caused reduction in the power consumption as shown in fig. 4, the increasing of the electrolyte temperature gives rise to minimize polarization of cathode and anode and increase the electrolyte conductivity. h. m. abbas and s. t. najim./ iraqi journal of chemical and petroleum engineering91,9 (2018) 21-27 22 30 40 50 60 70 electrolyte temperature (oc) 0.4 0.6 0.8 1 1.2 p ( k w .h /g ) s ( 15 mm ) cd ( 200 a /m2) cd ( 300 a /m2) cd ( 400 a /m2) fig. 4. effect of electrolyte temperature on power consumption with constant s 15 mm and cd 200, 300 and 400 a/m 2 when the electrolyte temperature increase current efficiency will increase, it can be referred to arrhenius equation which states that increasing of electrolyte temperature leads to increase the reaction rate of copper deposition, therefore the current efficiency will increase. decrease electrolyte temperature decreases acdr. it can be interpreting that the diffusion coefficient of the cupric ions will decrease with decreasing of the electrolyte temperature, so hindering mass transportation that is in a good agreement with ibrahim [19]. c. effect of the electrodes spacing as the electrodes spacing decrease the cathode purity increased very slightly, the possible explanation that the variation in electrodes spacing does not have a significant influence on the natural convection which affect the impurities motion during the process. when electrodes spacing increase cathode surface morphology become rougher as shown in fig. 2 (g, h and i), it can be interpreting that the electrolyte resistivity increase with increasing of the electrodes spacing, and that will causing a bad current density distribution through the cell producing unsatisfactory distribution of the deposit grains on the surface creating a rougher deposit form. it can be observed easily that increase electrodes spacing decrease acdr as shown by fig. 5, it can be explained that increase electrodes spacing would increase the electrolyte resistivity and that would reduce the electrical field intensity which drive the charging spices to deposit on the cathode surface. a negative influence of electrodes spacing increasing on current efficiency, the probable explanation that the unwanted reactions rates may be maximized. increase electrodes spacing would increase power consumption, it can be elucidated that electrodes spacing increasing would increase the electrolyte resistivity and that can be maximized the cell voltage due to highly hindering to electrical current passing through the electrolyte. the optimum operating parameters were obtained in exp. no. 7, the current density 200 a/m 2 , the electrolyte temperature 65 o c and the electrodes spacing 15 mm. 10 20 30 40 50 electrodes spacing (mm) 230 232 234 236 a c d r ( g /h .m 2 ) cd (200 a/m2) t (35 oc) t (50 oc) t (65 oc) fig. 5. effect of electrodes spacing on acdr with constant cd 200 a/m 2 and t 35, 50 and 65 o c 4.2. part two table 4 shows the actual cathode deposition rate, current efficiency and power consumption data resulted in this part. table 4. acdr, ce% and p of part two exp. no. acdr g / h.m2 ce % p kwh/kg 28 235.1 99.15 0.4590 29 235.4 99.27 0.4138 30 235.7 99.40 0.3707 31 234.7 98.97 0.5060 32 235.0 99.12 0.4436 33 235.4 99.28 0.4000 based on logical expectation that the electrolyte circulation with short electrodes spacing 15 mm can deteriorate the cathode purity due to high forced convection of charged contaminations species that may deposit on cathode surface, also short electrodes spacing can increased the chances of short circuit and reduced the current efficiency, hence another electrodes spacing of 30 mm was employed because it gave an acceptable results in part one. a. effect of the electrolyte residence time (ert) in general, electrolyte circulation increase cathode purity compared with stationary electrolyte state, for the same operating parameters purity was increased from 99.54% in exp. no. 8 to 99.87% in exp. no. 31. h. m. abbas and s. t. najim./ iraqi journal of chemical and petroleum engineering91,9 (2018) 21-27 22 besides that in electrolyte circulation state, decrease ert more than 4 hours leads to decrease cathode purity, it can be interpreting that the density gradient make an electrolyte loop between the cathode and the anode (natural convection), the electrolyte close the anode is denser than that in facade of the cathode, because the anode is the source of cupric ions by dissolution operation, while it is deposited on the cathode surface, the electrolyte loop is moving with a downward trend over the anode surface and an upward trend over the cathode surface. when the electrolyte is circulate, a flow pattern with a trend from the bottom to the top will be created, hence the upward electrolyte current close the cathode will be strengthened, upward flow has important influence on contaminations particle conduct, so more probability with lesser ert to contaminations deposited on cathode surface and deteriorate the purity. surface morphology in case of electrolyte circulation is better than electrolyte stationary situations. in addition, as the ert decrease the cathode surface morphology becomes slightly finer as shown in fig. 6, it can be clear up that ert decreases would increase the forced convection and that would decrease the nernst diffusion layer thickness and permits to produce a smooth copper deposition. in comparison, the electrolyte circulation slightly increased mass transport than stationary conditions, acdr increase from 234.3 in exp. no. 8 to 235.4 g / h.m 2 in exp. no. 33. also when ert decrease the acdr would increase, the feasible analysis that decreasing ert would increase the forced convection, and that would decreases copper ions near the anode and increases the copper ions near cathode, subsequently the natural convection from anode to cathode would increase and makes a quicker moving of copper ions. compare with stationary state, the circulation of electrolyte increase the current efficiency, ce% increase from 98.82% in exp. no. 8 to 99.28% in exp. no. 33. furthermore, it can be observed from table 4 that increasing of ert would decrease the current efficiency, it can be make clear that increase ert would decrease the forced convection and that would slows down the speed of copper ions from anode to cathode leads to minimize the reaction rate of copper deposition, therefore the current efficiency will decrease. as a rule, electrolyte circulation minimizes the power consumption, p decrease from 0.6064 in exp. no. 8 to 0.4000 (kwh/kg) in exp. no. 33. decrease ert would decrease power consumption, the possible explanation that the decreasing of ert would increase the forced convection which enhanced the removing of slimes adhered on anode surface and that would permits to easily passing of current and reduces the cell voltage beside the minimization of electrodes polarization. fig. 6. sem micrographs show the effect of ert and electrodes spacing on cathode morphology with cd 200 a/m 2 , t 65 o c, (a, b and c) s 15 with ert 6, 4 and 2 h respectively, (d, e and f) s 30 with ert 6, 4 and 2 h respectively b. effect of the electrodes spacing when the electrodes spacing increased from 15 to 30 mm with electrolyte circulation the cathode purity would slightly increase, as it happened in experiments 28 and 31when the purity was slightly increased from 99.85% to 99.87%, the possible explanation that the short electrodes spacing with electrolyte circulation will deteriorate the cathode purity due to high forced convection of the charged impurities species that may deposit on cathode surface. it can be observed that increase of electrodes spacing will decline the cathode surface morphology and become rougher as shown in fig. 6, it can be clarified that the electrolyte resistivity increase with increasing of the electrodes spacing, and that would generate a bad current density distribution through the cell producing unacceptable distribution of the deposit grains on cathode surface creating a rougher deposit. it can be notes from table 4 that when electrodes spacing increase acdr would decrease slightly, acdr decrease from 235.1 in exp. no. 28 to 234.7 g / h.m 2 in exp. no. 31, it can be clarified that increase electrodes spacing would increase the electrolyte resistivity and that would minimize the intensity of electrical field which drives the charging dissolution spices to deposit on the cathode surface. increase electrodes spacing would decrease the current efficiency as shown in table 4, ce% decrease from 99.15% in exp. no. 29 to 98.97% in exp. no. 31, may be the rates of unfavorable reactions will be maximized. as electrodes spacing increases the power consumption would decrease as shown in table 4, p decrease from 0.4590 in exp. no. 28 to 0.5060 kwh/kg in exp. no. 31, it can be interpreting that the electrodes spacing increasing would decrease the electrolyte conductivity and that can be maximized the cell voltage due to greatly h. m. abbas and s. t. najim./ iraqi journal of chemical and petroleum engineering91,9 (2018) 21-27 22 hindering to passing the electrical current through the electrolyte. finally, it can be considered that the optimum operating parameters were obtained in exp. no. 31, with current density 200 a/m 2 , electrolyte temperature 65 o c, electrodes spacing 30 mm and the electrolyte residence time 6 h, all these operating parameters produce a cathode copper with purity of 99.87% wt. cu, smooth and compact deposit morphology, actual cathode deposit rate 234.7 g / h.m 2 , current efficiency 98.97% and power consumption 0.5060 kwh/kg. 5conclusions 1increase current density will extremely deteriorate cathode purity and morphology, reduce the current efficiency and maximize the power consumption, while it increased acdr. 2increase electrolyte temperature will improve cathode purity and morphology, increase acdr and current efficiency and minimize the power consumption. 3increase electrodes spacing in stationary electrolyte will slightly weaken cathode purity and morphology, faintly reduce acdr and current efficiency and maximize the power consumption. while increase electrodes spacing with electrolyte circulation from 15 to 30 mm will slightly improve cathode purity only. ; 4in general, electrolyte circulation improves cathode purity and morphology compared with stationary electrolyte state, furthermore decrease ert will enhance cathode morphology, rise acdr and current efficiency values and minimize power consumption, while ert less than 4 hours leads to drop cathode purity. references [1] lusty p., and gunn a., “challenges to global mineral resource security and options for future supply”, geological society, london, special publications 393, no. 1, pp. 265-276, (2015). [2] eugie k. and wang y., “analysis of copper„s market and price-focus on the last decade„s change and its future trend”, international journal of scientific & technology research, vol. 4, pp. 54-61, (2015). [3] boulamanti a and jose a., “production costs of the non-ferrous metals in the eu and other countries: copper and zinc”, resources policy 49, pp. 112-118,(2016). [4] ghodrat m., rhamdhani m., brooks g., masood s., and corder g., “ techno economic analysis of electronic waste processing through black copper smelting route”, j. of cleaner production 126, pp.178190, (2016). [5] stelter m., and hartmut b., “process optimization in copper electrorefining” advanced engineering materials 6, no. 7, pp 558-562, (2004). [6] john j. and martin t., “the international copper industry”, woodhead publishing ltd, (2002). [7] schlesinger m. and paunovic m., “modern electroplating”, fifth edition, john wiley & sons, (2010). [8] mark e., matthew j., kathryn c.., and william g., “extractive metallurgy of copper”, fifth edition, elsevier ltd, (2011). [9] ntengwe f., mazana n, samadi f, “the effect of impurities and other factors on the current density in electro-chemical reactors”, international journal of chemtech research, vol.2, no.2, pp 1289-1300, (2010). [10] ntengwe f., “the effect of impurities, smootheners and other factors on the recovery of copper from solutions”, m.sc. thesis, south africa university, zambia, (2008). [11] derek p. and frank w., “industrial electrochemistry”, second edition, springer science + business media, llc, (1993). [12] fischer, h., “electrolytic deposition of metals and electrocrystallization” berlin, springer, (1954). [13] lee s., “encyclopedia of chemical processing”, taylor & francis group, llc, (2006). [14] kalliomaki t.,"effect of composition and temperature on physico-chemical properties of copper electrolyte", m.sc. thesis, aalto university school for chemical technology, (2015). [15] aromaa, j.,“electrochemical engineering” in encyclopedia of electrochemistry, wiley-vhc verlag gmbh & co. kgaa, pp. 161–196, (2007). [16] l.kruyswijk., “electrorefining of base metal refinery residue copper alloy for platinum group metal recovery”, m.sc. thesis, university of cape town, (2009). [17] free m., moats m., houlachi g., e. asselin, a. allanore, j. yurko and s.wang, “electrometallurgy 2012”, held during the tms 2012 annual meeting & exhibition, john wiley & sons, (2002). [18] najim s. t., " estimation of mass transfer coefficient for copper electrowinning process", journal of engineering, vol.22, p.158-168, (2016) [19] ibrahim m., h., najim s. t., "determination of mass transfer coefficient for copper electrodeposition by limiting current technique", al-nahrain journal for engineering sciences, vol.20 (3), p.666-672, (2017) ijcpe vol.9 no.1 (march 2008) 15 iraqi journal of chemical and petroleum engineering vol.9 no.1 (march 2008) 15-21 issn: 1997-4884 preparation of polyvinyl alcohol from local raw material cecelia k. haweel*, and saad h. ammar * chemical engineering department college of engineering university of baghdad – iraq abstract polyvinyl alcohol, (pva) was prepared using polyvinyl acetate emulsion (manufactured by al-jihad factory, that-al-sawary company) as a local raw material. in this investigation, polyvinyl acetate emulsion was converted to solid form by coagulation the polymer from its emulsion using sodium sulphate salt as coagulant aid, then alcoholyzed the solid polyvinyl acetate in methanol using sodium hydroxide as catalyst, polyvinyl alcohol produced by this method is a dry, white to yellow powder. three affecting variables on the degree of hydrolysis of pva were studied, these variable are catalyst to polymer weight ratio in the range of 0.01 – 0.06, reaction time in the range of 20 – 90 min, and reaction temperature in the range of 25 – 50 oc. the effect of degree of hydrolysis of pva produced on its properties such as water solubility and degree of polymerization were studied also. finally the alcoholysis reaction kinetics were studied to determine the reaction constants such as initial rate constant and degree of autocatalytic effect of the alcoholysis reaction. it was found that the degree of hydrolysis of formed polyvinyl alcohol increase with increasing of variables catalyst concentration, reaction time and reaction temperature, furthermore, the water solubility of pva increase with increasing degree of hydrolysis up to about 87 % after this value the solubility is decrease, also the degree of polymerization of pva decrease with increasing of degree of hydrolysis up to about 89 %. keywords: polyvinyl alcohol, alcoholysis reaction, polyvinyl acetate emulsion, coagulation. introduction polyvinyl alcohol, (pva) is a polyhydroxy polymer, , containing significant number of oh-groups, and consequently a water soluble synthetic resin. it is a dry solid and available in granular or powder form, white to yellow in color. pva is readily obtainable from hydrolysis of polyvinyl acetate or other polyvinyl esters by replacement of acetate groups by hydroxyl groups in the polymer chain, using either base or acid catalyst [1]: (1) university of baghdad college of engineering iraqi journal of chemical and petroleum engineering o c o ch3 nch2 ch free radical initiator polymerization ch2 ch o c o ch3 n vinyl acetate polyvinyl acetate ch2 oh n ch preparation of polyvinyl alcohol from local raw material ijcpe vol.9 no.1 (march 2008) 16 (2) (3) the theoretical monomer, vinyl alcohol evidently does not exist in free state, whenever, it rearranges to give its tautomer, acetaldehyde [2]: ch2:choh ch3:cho (4) discovery of polyvinyl alcohol was credited to german scientists, w. o. herrman and haehnel in 1924 [3] and the polymer was commercially introduced into united state in 1939 [4]. pva is manufactured commercially by several methods; alkaline hydrolysis is usually used as an industrial scale. sodium hydroxide and sodium methoxide are the most important catalyst for alcoholysis with present of alcohol such as methanol or ethanol. other alkaline catalyst may be employed in alcoholysis reaction for example potassium hydroxide, guanidine carbonate, sodium methyl carbonate and sodium ethoxide [2]. pva can be also made by an acidolysis process, this can involve both alcoholysis reaction (ester interchange) when working in an anhydrous system with present of alcohol, and a hydrolysis reaction when a polyvinyl acetate emulsions or of finely divided water suspensions are used as the starting material, usually sulfuric acid, hydrochloric acid or any other strong mineral acid is employed as the acid catalyst, this process is used industrially only to a very limited extent [2]. a number of other methods for the manufacture of pva have been used , these employ starting materials other than polyvinyl acetate ,often the polyvinyl alcohol made by these methods have specific properties such as tacticity , better cold-water solubility and steroregularity [5]. pva is one of very few high molecular weight commercial polymers that are water soluble, the basic properties of pva such as water solubility depend on the degree of replacement of acetate groups by hydroxyl groups (degree of hydrolysis) and the degree of polymerization. the most common commercial grades classified by the percentage hydrolysis and degree of polymerization; therefore, there are three important commercially available grades of pva distinguished by the mole percent residual acetate groups in the polymer chain as follows [5]: 1. fully hydrolyzed (1 – 2 mol% acetate groups ) 2. intermediate hydrolyzed (3 – 7 mol% acetate groups ) 3. partially hydrolyzed (10 – 15 mol% acetate groups ) pva with other degree of hydrolysis are also produced, but collectively they have a much smaller market share than any of the three principal grades. in term of the degree of polymerization (based on the viscosity at 20 oc of 4% aqueous solution of pva), there are four general molecular weight ranges(5): 1. low viscosity grade (5 –7 cp) 2. intermediate viscosity grade (13 – 16 cp) 3. medium viscosity grade (28 – 32 cp) 4. high viscosity grade (55 – 65 cp) these grades of polyvinyl alcohol lend to variety of applications. the principle applications are in textile industry for warp sizing, as emulsifier agent in vinyl acetate emulsion polymerization systems, as a component in aqueous adhesives, for the production of polyvinyl acetyls, e.g., polyvinyl butyral for safety glass. significant volumes are also used in such diverse application as joint cements for building construction, water-soluble film for hospital laundry bags, emulsifiers in cosmetics, temporary protective films to prevent scratching of high polished surfaces, soil binding to control erosion, paper coating, and in smaller amounts as the binder for phosphorescent pigments and dyes in television tubes and in other optical applications such as polarization lenses [2]. experimental work materials 1. commercial polyvinyl acetate emulsion, manufactured by al-jihad factory, from that– al–sawary company, baghdad, was used as starting material. 2. commercial grade (hopkin & williams) of 99.5% pure methanol was used as alcoholysis medium. 3. analytical reagent grade sodium hydroxide was used as alkaline catalyst. 4. commercial grade sodium sulphate (bdh chemicals ltd) was used as coagulant agent. 5. analytical grade (hopkin & williams) methyl acetate was used as precipitation agent for polyvinyl alcohol. ch2 ch ch3oh naoh o c o ch3 pva n polyvinyl acetate + methanol alcoholysis + oco ch3 n ch3 methyl acetate n ch2 oh n ch or h2so4 ch2 ch h2so4 o c o ch3 ch2 pva ch oh c ch3 o n polyvinyl acetate + n h2o hydrolysis + noh acetic acid n cecelia k. haweel and saad h. ammar ijcpe vol.9 no.1 (march 2008) 17 experimental procedure coagulation process of polyvinyl acetate emulsion polyvinyl acetate was coagulated from its emulsion by using solution of sodium sulfate in the presence of methanol solvent and water, according to the following recipe: materials weight parts polyvinyl acetate emulsion 100 sodium sulfate salt 100 water 250 methanol 25 – 50 sulfuric acid 1 – 2 in one–liter flask, 200 gm of polyvinyl acetate emulsion (53% by weight solid content) was stirred with 50 gm methanol, and it was overlaid with aqueous solution of sodium sulfate salt (consists of 200 gm na2so4 and 500 gm water) and 2 gram sulfuric acid. the mixture was stirred for 20 minutes at a temperature in the range of 30–50oc. after settling time of about 30 min. at room temperature, the polyvinyl acetate was coagulated and three layers were present as shown in fig. (1), the top or the first layer is emulsifiers (soaps), the intermediate layer is liquid phase (water, dissolved salt, and methanol), and the bottom layer is precipitated polymer. the emulsifiers’ layer was removed mechanically and the polymer was filtered from the liquid phase, the resultant filtrate is recycled for treating another batch of emulsion. the polymer was then washed several times with water and filtered after each time. the resulting polymer consists of 75-80 % polymer and 20-25% water. preparation of polyvinyl alcohol (alcoholysis process) preparation of polyvinyl alcohol was carried out in a stainless-steel jacketed reactor with a total capacity of 1.4 liter which was heated to the required temperature by hot water circulation in the jacket of the reactor, the reactor was equipped with variable speed stirrer, reflux condenser to prevent losses of vapor from the reactor during the hydrolysis reaction, thermometer, and thermostat. the laboratory experimental unit is shown in fig. (2). fig. 2 alcoholysis process unit 200g of pretreated solid polyvinyl acetate (containing about 20% water) was dissolved at the desired temperature in 400gm of methanol by stirring in the reactor, after it reached the same temperature with the jacket; the desired amount of sodium hydroxide catalyst solution in methanol was added to the reactor. the sodium hydroxide solution was prepared separately by dissolving the desired amount of sodium hydroxide thermostat reflux condenser alcoholysis reactor heating vessel immersion heater temperature sensor water pump preparation of polyvinyl alcohol from local raw material ijcpe vol.9 no.1 (march 2008) 18 catalyst in 80g of methanol, therefore the concentration of polyvinyl acetate in the total reaction mixture being in the range of 15 – 30 % by weight and the methanol to water weight ratio in the reaction mixture was about (90 methanol:10 water). the reaction mixture thickened after 10 min. and the gel that formed was comminuted by raising the speed of the stirrer. the sample was removed periodically, from the reactor and immediately, the sodium hydroxide which still present in the sample, has been neutralized by strong hydrochloric acid, then polyvinyl alcohol formed in the sample was precipitated in methyl acetate by agitation at about 25° c. each polyvinyl alcohol sample was very effectively isolated from the liquid phase by suction filtration on a textile filter under vacuum operation and then dried. experiments setup in this work, two set of experiments are considered, the first set at 25° c and the second set at 50° c. in each set of experiments, the two variables, catalyst ratio and reaction time were studied. the catalyst ratio was varied among (0.01, 0.0266, 0.0433, and 0.06 weight of cat. / weight of polyvinyl acetate), and the reaction time was varied among (20, 43.3, 66.6, and 90 min.). analysis and testing of pva(6) volatile content volatile content is the percentage weight loss of polyvinyl alcohol on drying at 105oc to constant weight. accurately weighting about 5 gm of the sample was placed into a weighting bottle, dry it at 105 °c to constant weight; allowed it to cool in a desicator and weighting the sample again. the volatile content was calculated to two decimal places from the formula: 100% s ws  v r (5) and the pure component of polyvinyl alcohol can be calculated from: p = 100 – rv (6) the values taken are the average of two determinations. degree of hydrolysis accurately weighting about 3 gm of sample and 100 ml of water were placed into a stoppard conical flask; and the sample was dissolved by heating then cooled at room temperature. 25 ml of 0.1 n naoh solution was added to the solution and kept at room temperature for at least 2 hr. then 25 ml of 0.1 n sulfuric acid was added and excess acid was titrated with 0.1 n naoh using phenolphthalein as an indicator, until a pale pink color was persisted in the solution. the volume of solution consumed in this titration was [a] ml. the percentage weight of residual acetic acid radical, based on the pure component as well as the mole percent hydrolysis was calculated to two decimal places from the following formula:   percent p s f a 0.6 a    (7) percent mole a 0.1601 60.06 a 44.05 b  (8) x = 100 – b mole percent (9) average degree of polymerization (pa) & molecular weight. about 10gm of sample was weighted into a stoppered conical flask and 200 ml of methanol was added, followed by 3 ml of 12.5 n sodium hydroxide (with samples of not less than 97 mole % hydrolysis) or 10 ml of 12.5 n sodium hydroxide (with samples of less than 97 mole % hydrolysis). after stirring the solution was heated for 1 hr in a water path at 40oc, to hydrolyze the polymer completely. the solution was then washed thoroughly with methanol to remove the sodium hydroxide and sodium acetate. the solution was then transferred to a watch glass and dried to remove the methanol. 1gm of the dried liquid phase precipitated polymer soap figure (1) representation of polyvinyl acetate coagulation cecelia k. haweel and saad h. ammar ijcpe vol.9 no.1 (march 2008) 19 sample was weighed, and dissolved, with heating in 100 ml of water. then cooled at room temperature, and filtered carefully. 10 ml of the filtered solution was placed in a capillary viscometer (cannon fenske no. 100) and the time of flow of solution was measured at 30±0.1 °c. the same capillary viscometer was used to measure the time of flow of water at the same temperature. 20 ml of the same filtrate was taken separately onto an evaporating dish of known weight and evaporated to dryness. the residue was further dried at 105  2oc to constant weight, and the concentration (in g/l) was determined. the average degree of polymerization was calculated from the formula:          ot 1 t log vc 2.303 8.29 410 log 1.613 a p log (10) where:         ot 1 t log vc 2.303 = limiting viscosity (g-1 l-1) and the average molecular weight of polyvinyl alcohol was calculated from: average molecular weight of pva = pa × 44 (11) solubility in water [5] the water solubility of pva was calculated after 30 min. at 40° c by dissolving 4 parts by weight of pva in 96 parts of water. results and discussion when polyvinyl acetate is alcoholyzed with sodium hydroxide as basic catalyst in methanol, a mixed polymer, or hydrolyzed polyvinyl acetate, is formed which contain both hydroxyl and acetyl groups. as a ratio of hydroxyl to acetyl groups increases, the solvent – solute relationship in the reaction mixture is changed, i.e. the alcoholyzed acetate become increasingly water – susceptible, passing through a stage at which it is swollen and somewhat water – solubility. the essential over-all reaction may be represented in terms of the simple monomeric units, as follows: (12) the results of typical alcoholysis experiments of polyvinyl acetate to polyvinyl alcohol are tabulated in table (1). table (1) results of degree of hydrolysis (x) of pva of alcoholysis reaction experiments of polyvinyl acetate to polyvinyl alcohol using sodium hydroxide as alkaline catalyst temp.(°c) time (min.) catalyst ratio 0.01 0.02667 0.04334 0.06 25 20 56.6 58.34 65 73 43.3 59 60.5 67 75.99 66.6 67.71 76 82 87.9 90 78.77 89.65 97.5 98.31 50 20 59 63 69.5 75.55 43.3 61.99 68.8 72 79.46 66.6 65.12 77.74 83.83 90 90 79 90.69 97.25 99 effect of catalyst ratio results of the study of the effect of catalyst ratio on the degree of hydrolysis of polyvinyl alcohol at different reaction time and at temperature of 25oc and 50oc respectively are shown in fig.s (3) and (4). it is clear, from these fig.s that the degree of hydrolysis of pva increases with increasing of catalyst ratio at constant time, [i.e. the time required to reach desired degree of hydrolysis decreases with increasing of catalyst concentration]. for example, increasing the catalyst ratio from 0.01 to 0.02667 at 25oc and 90 min. causes an increase in degree of hydrolysis from 78.77% to 89.65%. increasing the catalyst concentration leads to a lowering the activation energy required to bring the anion of the alcohol (ro-) up to the carbonyl carbon atom of the acetate group in the first step of alcoholysis reaction as shown in equation (13). (13) effect of reaction time fig.s (5) and (6) and table (1) show the effect of reaction time on the degree of hydrolysis of pva at different catalyst ratio and at temperatures of 25oc and 50oc respectively. the rate of degree of hydrolysis of pva increase with increasing of reaction time. as reaction time increase, the number of hydroxyl groups increase in the polymer chain, and rate of the alcoholysis reaction increase continuously because of the autocatalytic effect of these functional groups as explained by sakurada [7] and l. m. minsk [8]. it is clear from each curve in fig.s (5) and (6), that the slopes at selected points of x (degree of hydrolysis), increase with increasing the reaction time, this mean that the rate of reaction increase as shown in table (2). ch2 ch ococh3 ch2 o h ch n n + +nch3oh nch3ococh3 pv o c o or ch3 pv o c or ch3 o+ preparation of polyvinyl alcohol from local raw material ijcpe vol.9 no.1 (march 2008) 20 effect of alcoholysis reaction on the degree of polymerization of pva fig. (7) shows the effect of alcoholysis reaction on the degree of polymerization of pva. the reaction conditions are: temperature = 25° c, catalyst ratio=0.06. it is clear from this fig. that a noticeable decrease of the degree of polymerization of formed pva with increasing of degree of hydrolysis up to degree of hydrolysis of 75%, followed by slightly decrease up to 89%. decreasing of degree of polymerization of pva during the alcoholysis reaction may be attributed to that the alcoholysis reaction causes some degradation of the original polyvinyl acetate , this effect is probably due to fission of chain branching through the methyl unit of the acetoxy group in the polymer chain [5]. effect of degree of hydrolysis on the water solubility of pva fig. (8) shows the effect of degree of hydrolysis on the water solubility of pva, it is shown from this fig. that the water solubility of pva is very affected by the degree of hydrolysis at constant temperature. the solubility of pva in water increase with increasing of degree of hydrolysis (i.e. number of hydroxyl groups in polymer chain) at constant temperature up to about 87% (partially hydrolyzed), after this value the solubility of pva decreases. fully hydrolyzed pva has low water solubility because of the high number of hydrogen bonding between the intra – and intramolecular hydroxyl group which is greatly impeding the pva solubility in water. the residual acetate groups in partly hydrolyzed pva are essentially hydrophobic and weaken the intra – and intramolecular hydrogen bonding of adjoining hydroxyl groups. and this, increases the solubility of pva, as explained by martin k. lindemann [5]. kinetics study the kinetics of alcoholysis reaction of polyvinyl acetate in methanol using sodium hydroxide as alkaline catalyst was studied. the aim of this study is to find the initial rate constant, ko and degree of autocatalytic effect, m (which means the degree of acceleration during the hydrolysis reaction) at different catalyst concentration and at temperature of 25 and 50° c respectively, and to determine the effect of catalyst ratio used in the initial reaction mixture and temperature on the ko and m. the initial rate constant, (ko) and degree of autocatalytic effect, m can be calculated at different catalyst ratio by fitting the data in table (1) as a linear equation using equations bellow: dx/dt =ko[(1+mx) (1-x)] (14) dx/dt [1/ (1-x)] =ko+komx (15) where k= ko+komx (16) from each plot of (x) verses (t), the slope of each curve is obtained at suitably selected (x). these slopes represent the values of (dx/dt), straight lines can be obtained by plotting of (dx/dt[1/(1-x)]) versus (x) at different catalyst ratio and at temperature of 25 and 50° c respectively according to equation (15). the data of these figures are shown in table (2), where the slope is (kom) and the intercept is (ko), therefore the results of ko and m can be obtained as tabulated in table (3). figures (9) and (10) show the effect of catalyst ratio on the initial rate constant and degree of autocatalytic effect respectively, it is clear from figure (9) that the initial rate constant, ko increase with increasing the catalyst concentration, but the degree of autocatalytic effect (m) decrease with increasing of catalyst concentration. the rate constant (k) of the hydrolysis reaction after a degree of hydrolysis (x) can be calculated from equation (16), it is clear from figures (11) and (12) that the rate constant of the hydrolysis reaction increase with increasing degree of hydrolysis (i.e. the rate of hydrolysis reaction increases continuously), and the relationship between k and x is linear because the autocatalytic effect of this reaction. table (2) results of dx/dt [1/ (1-x)] verses x at different cat. ratio and temperature temp. (°c) cat. ratio x dx/dt [1/ (1-x)] 25 0.01 60 0.66675 66 1.18617 70 1.558467 76 2.5 0.0266 60 0.673 70 1.8334 80 3.5105 86 5.2628 0.0433 66 0.5392 70 1.2766 80 3.125 90 8.182 0.06 74 0.7692 80 1.81 90 5 96 14.795 50 0.01 60 0.375 64 1.13056 70 1.556 76 2.334 0.0266 64 0.463 70 1.1853 80 2.3684 86 4.2093 0.0433 70 0.476 76 1.231 84 3.125 90 6.48 0.06 76 0.726 84 2.138 90 4.2 96 12 cecelia k. haweel and saad h. ammar ijcpe vol.9 no.1 (march 2008) 21 table (3) results of initial rate constant and degree of autocatalytic – effect temp. ( °c) cat. ratio ko m 25 0.01 4.675 0.019 0.0266 7.926 0.0179 0.0433 11.654 0.01587 0.06 19.434 0.01389 50 0.01 6.376 0.01788 0.0266 7.149 0.01664 0.0433 13.09 0.01466 0.06 18.001 0.01356 conclusions 1. a dry and solid powder form polyvinyl alcohol can not be obtained from polyvinyl acetate emulsion directly, because the water present in the emulsion solublies the formed pva and the product still in aqueous solution state. it can be claimed from the literature that if polyvinyl acetate is available in emulsion state, the hydrolysis process is carried out in aqueous media using strong acid catalyst such as sulfuric acid, the reaction needs long time and dark color, unsuitable for many uses pva is obtained. 2. polyvinyl acetate emulsion can be treated to convert the emulsion to solid state by coagulation the polymer from its aqueous emulsion using sodium sulphate salt as coagulant agent. the final treated polymer contains about 20% by weight water. 3. solid polyvinyl acetate was alcoholyzed easily in methanol using sodium hydroxide as alkaline catalyst, the parent polyvinyl acetate containing a small amount of water, and the final weight ratio of methanol – water in the reaction mixture is about (90 methanol : 10 water). polyvinyl alcohol produced in this method is dry solid, white to yellow powder. 4. in the alcoholysis process, three variables of catalyst concentration, reaction time and reaction temperature are affecting the degree of hydrolysis of polyvinyl alcohol in the order: catalyst ratio > reaction time > reaction temperature a. degree of hydrolysis of pva increase rapidly with increasing the catalyst concentration at constant reaction time and temperature. b. degree of hydrolysis pva increase continuously with reaction time because of the autocatalytic effect of the alcoholysis reaction. c. degree of hydrolysis of pva increase slightly with increasing of reaction temperature. the change of alcoholysis reaction rate with temperature follows the arrhenius temperature dependence equation. 5. at constant temperature the water solubility of product pva increase with increasing of degree of hydrolysis up to 87 %, after this value the solubility of pva is decrease. 6. the degree of polymerization of formed pva decrease slightly with increasing of degree of hydrolysis, after a degree of hydrolysis about 89 %, the degree of polymerization is almost constant. references 1. david l. cincera, "encyclopedia of chemical technology", 3 rd ed., vol. 23, john wiley and sons, new york, (1983). 2. martin k. lindeemann, "encyclopedia of polymer science and technology", vol. 14, john wiley and sons, new york, (1971). 3. willy o. herrmann & wolfram haehnel, u.s. pat. 1,672,156 (1928). 4. norman d. scott & john e. bristol, u.s. pat. 2,266,996 (1939). 5. finch c. "polyvinyl alcohol properties and applications", john wiley and sons, london (1973). 6. japan industrial standard k6726 – 1965, (2003), internet connection 7. sakurada, chemical abstract, vol. 44, 8161b (1950). 8. minsk l. and kenyon w., j. amer. chem. soc., 63, 2715 (1941). available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.20 no.2 (june 2019) 1 – 9 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: abeer i. alwared , email: dr.abeer.wared@coeng.uobadghdad.edu.iq, name: nada abdulrazzaq, email: nnabdulrazzaq@coeng.uobadghdad.edu.iq, name: baseem al-sabbagh, email: b.al-bagh@coeng.uobadghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. micro-bubble flotation for removing cadmium ions from aqueous solution: artificial neural network modeling and kinetic of flotation abeer i. alwared a , nada abdulrazzaq b and baseem al-sabbagh c a environmental eng. department, university of baghdad b chemical eng. department, university of baghdad c envcironmental eng. department, university of baghdad abstract in this work, microbubble dispersed air flotation technique was applied for cadmium ions removal from wastewater aqueous solution. experiments parameters such as ph (3, 4, 5, and 6), initial cd(ii) ions concentration (40, 80, and 120 mg/l) contact time( 2, 5, 10 , 15, and 20min), and surfactant (10, 20and 40mg/l) were studied in order to optimize the best conditions .the experimental results indicate that microbubbles were quite effective in removing cadmium ions and the anionic surfactant sds was found to be more efficient than cationic ctab in flotation process. 92.3% maximum removal efficiency achieved through 15min at ph 5, sds surfactant concentration 20mg/l, flow rate250 cm 3 /min and at 40mg/l cd(ii) ions initial concentration. the removal efficiency of cadmium ion was predicted through 11 neurons hidden layer, with a correlation coefficient of 0.9997 between ann outputs and the experimental data and through sensitivity analysis, ph was found to be most significant parameter (25.13 %).the kinetic flotation order for cadmium ions almost first order and the removal rate constant (k) increases with decreasing the initial metal concentration. keywords: cadmium ions, flotation, microbubbles, ann model, kinetic flotation rate. received on 12/01/2019, accepted on 09/02/2019, published on 30/06/1029 https://doi.org/10.31699/ijcpe.2019.2.1 1introduction the presence of heavy metals in water is a universal environmental concern from landfills and industrial. ‎[1]. among various organic and inorganic pollutants, heavy metal ions are very toxic and carcinogenic in nature. heavy metals enter into the food chain through the disposal of wastes into water bodies ‎[2] and possibly cause severe health problems, when their concentration exceeds their permissible, also they are very difficult to eliminate naturally from the environment as it was nonbiodegradable pollutants ‎[3]. cadmium is a highly toxic element and its exposure may results which called “cadmium blues” results from respiratory damage after few weeks. highly exposures causes tracheo-bronchitis, pneumonitis, diarrhea, stomach pains and severe vomiting, bone fracture, reproductive failure and possibly infertility. permissible limits of cd (ii) ions in drinking water is 0.005 mg/l and above this level may cause serious infection ‎[4]. many methods are available to remove heavy metals concentration from water, such as precipitation, flotation, ion exchange, solvent extraction, adsorption, and cementation onto iron, membrane processing and electrolytic methods ‎[5]. the selection of a particular treatment depends on a number of factors such as waste type, contaminant concentration, level of cleanup required and economics ‎[6]. flotation is one of the most effective separation techniques from the above processes .nowadays, many industrial applications use microbubbles of air and oxygen in water treatment application due to its superior efficiency, compared with conventional methods ‎[7], ‎[8]. flotation processes utilize microbubbles are very effectively for removing low-density particulate matter from water ‎[9] , which act as carriers for fine particles, which are lifted up from the bottom of the column. different flotation techniques processors available depending on the microbubble generation process, like: dissolved-air flotation, dispersed-air flotation or electroflotation ‎[10], ‎[11]. traditional flotation assisted with microbubbles (30– 100 μm) was used in the recovery of fine mineral particles (<13 μm), as well as separation to remove pollutants. the microbubble has advantage of improving the separation efficiencies as compared with coarse bubbles, particularly those for the ultrafine (<5 μm) ore particles. by decreasing the bubble size distribution (through the injection of small bubbles), the bubble surface flux will be increased and the fines capture. https://doi.org/10.31699/ijcpe.2019.2.1 a. i. alwared et al. / iraqi journal of chemical and petroleum engineering 20,2 (2019) 1 9 2 dissolved air flotation with microbubbles, treating water, wastewater and domestic sewage is known for a number of years and is now gradually entering in the mining environmental area [12]. though there are several studies on the removal of heavy metal by dispersed air flotation such as those applied by[13][14][15], more of them used frother in order to reduce the size of the air bubbles in a flotation cell to present sufficient surface area for collection. artificial neural network are powerful techniques used in modeling complex systems that seeks to simulate human brain behavior by treatment of data on the basis of trial and error. ann has been identified as tool to determine and optimize complicated nonlinear relationships between parameters [16]. numerous studies have been conducted in which anns were used in different wastewater processes such as flotation [17], advanced oxidation process[18] power generation by microbial fuel cell[19], adsorption[20] , and sorptive flotation [21]. the scope of this study was to investigate the effect of microbubbles in the removal efficiency of cd(ii) ions from aqueous solution at different parameters , ionic strength , flotation kinetic and use the artificial neural network (ann) to describe this behavior. 2flotation kinetics the variation of floated concentration with time will be studied by flotation kinetics, which are useful in the elucidation of the mechanism of the process, and serve as predictive tools in the implementation of flotation technology [22] the flotation rate is equal to the rate of change of concentration of floatable material in the cell, is (1) where, k is the flotation rate constant and the value of (n) denotes the order of the equation. by integration eq. (1) with n= 1 (first order) gives: c = co (2) where co= initial concentration, and c = the final concentration of valuable material remaining at time t. taking the ln of eq.(2): ln = kt (3) a high rate constant shows that certain species floats quickly while a low rate constant indicates slow flotation[23]. 3experimental work the flotation experiments were carried out in a glass tank with 33cm in length, 19cm in height and 8 cm in width as shown in fig. 1 the tank was operated at batch mode for the liquid phase, and continuous flow with respect to air which was provided by a compressor (type: samtong) in which it was compressed from1 bar to up to 7 bar and then passed into the microbubble generator (mbg) which consists of a ceramic micro-porous diffuser (point four tm diffuser) (riverforest corporation, usa, as mk-iii). the dissolution of gas into the solution was achieved inside the mbg by applying a high pressure. the microbubbles (mean diameter= 100μm) were generated by the release of pressure, and then entered to the tank through a pre-calibrated rotameter (02.5cm 3 /min). the desired concentration of cadmium ions was prepared by dissolving the calculated amount of cd(no3)2.4h2o in distilled water. the main physicochemical properties of the cadmium ions was shown in table 1 .cd(ii) ions feed gently from the top of the tank. simultaneously, the tank was pressurized so as to prevent liquid to spew from the holes[24], then samples were drawn through port at the center of the surface (19cm high and 8 cm) of the tank at different periods ( 2, 5, 10, 15 and 20 minutes) . firstly, 2ml of solution was drained from the port before withdrawing each sample in order to reduce the entrainment of air bubbles. the concentration of the cd(ii) ions was determined by using flame atomic absorption spectrophotometer (aas; shimadzu, model: 7200, japan). the initial ph of the working solutions was adjusted by the addition of 1 mol/l naoh or hcl using a ph meter (wtw, inolab 720, germany) and all experiments were carried out at room temperature. hcl was used to clean the tank between experiments and then washed twice with distilled water. table 1. main physicochemical properties of cadmium ion property cadmium nitrate tetrahydrate appearance white colorless crystals chemical formula cd(no3)2.4h2o molecular weight (g/mole) 308.7 atomic weight (g/mole) 112.7 density (g/cm 3 ) 2.45 solubility in water g/100 ml at 20 º c 136 hydrated ionic radius, å 4.26 electronegativity 0.95 company bdh england fig. 1. experimental flotation apparatus, with(a= operating tank ; b= microbubble diffuser ; c= diffuser bed ; d=air bubble supply ; e = pipe ; f=flow meter http://en.wikipedia.org/wiki/molar_mass http://en.wikipedia.org/wiki/density http://en.wikipedia.org/wiki/solubility http://en.wikipedia.org/wiki/water a. i. alwared et al. / iraqi journal of chemical and petroleum engineering 20,2 (2019) 1 9 3 4results and discussion 4.1. ann model develop ann model was developed using levenberg– marquardt backpropagation (lma) training algorithm for correlating the removal efficiency of cd(ii) ions from aqueous solution. this algorithm was determent using matlab program version 78.2.0.701 (r2013b). randomly divide the subset of 100 experimental data into; 60 %, 20% and 20% as training set, validation set, and testing set, respectively. fig. 2 indicate the best topology for ann for cd(ii) ions removal and the variation of parameters was calculated at (6:18:1) depending on the rmse of the prediction and training sets , which was the highest at hidden neurons no. 2 then decreased significantly to reach the minimum values 1.062 at 11 hidden neurons as can be seen in fig. 3, the dependence between rmse and the neuron number for the lma algorithm. fig. 4 shows that the training was disabled after epoch 15 when the best validation performance was 0.77385 and the best regression for training, validation and testing for the levenberg-marquardt algorithm was set in fig. 5, with correlation coefficients of 0.99725, 0.99393, 0.95795 and 0.99357for training, validation, testing and all data. the correlation coefficient between predicted and experimental data approves that the ann model can efficiently simulate the removal efficiency with correlation coefficient 0.9997as can be seen in fig. 6. fig. 2. ann best architecture model fig. 3. rmse at different hidden neurons no fig. 4. mean square errors training, validation, and testing for the levenberg–marquardt algorithm fig. 5. regression analysis for the levenberg-marquardt algorithm 0 1 2 3 4 5 0 1 2 3 4 5 6 7 8 9 1011121314151617181920 r m s e no. of nueron a. i. alwared et al. / iraqi journal of chemical and petroleum engineering 20,2 (2019) 1 9 4 fig. 6. relationship between predicted and experimental values of the output 4.2. effect of surfactant type fig. 7 presents a comparison between two types of surfactants ;sodium dodecylsulfate surfactant (sds) as anion surfactant and cetyltrimethyl ammonium bromides (ctab) as cation surfactant, at the same concentration (10 mg/l), while all other parameters were kept constant ph 6.8, air flow rate 2.5 ml/min and cd(ii) ion concentration= 40 mg/l) , it can be seen that the removal of cd(ii) ions reached 85% and 60% by using sds and ctab surfactant, respectively. that‟s meant the anionic surfactant (sds) is more efficient than the cationic surfactant (ctab) and will be used in the next experiments. the desired collector type depends upon ph value of a solution. generally, an anionic collector is required for ph (1-7) due to that metal ion is on cationic shapes. on higher ph, cationic collectors could be required when metal ion was existing as an anion [25][26]. fig. 7. influence of surfactant type on the removal of cd(ii) ions 4.3. influence of ph in order to investigate the influence of solution ph on the separation efficiency of cadmium ions towards the collector used in microbubble dispersed air flotation system, different ph values (3,4,5and 6) were tested while keeping other parameters constant (sds concentration= 10mg/l, air flow rate 250 cm 3 /min and cd(ii) ion concentration= 40 mg/l), fig. 8 shows that the removal efficiency increased suddenly at the first 2 minute, then it began to increased slowly with time due to decreasing sds concentration with time. the maximum removal efficiency achieved at ph5 was (79.2%), while it decreased for ph less than 5 because the competition between cd(ii) ions and h ions for collector, this results agree with the finding of[13][22] also a good agreement between the experimental and predicted data can be seen from the figure. table 2 presents the removal rate constant (k) at various ph , for this table it can be noticed that the removal rate constant increased with measuring ph value and it reached 4.248*10^ -12 min at ph6 fig. 8. removal efficiency of cd (ii) ions as a function of ph table 2. kinetic flotation at various ph effect of ph ph=4 ph=5 ph=6 k×10 2 (min -1 ) 3.378 3.834 4.248 4.4. influence of sds surfactant concentration different sodium dodecylsulfate surfactant (sds) concentrations (0, 10, 20 and 40mg/l) were used while other parameters were kept constant (ph 5, flow rate =250cm 3 /min, cd(ii) ion concentration = 40mg/l). fig. 9 shows that the removal of cd (ii) ion reached (92.3%) at 15 min at sds concentration of was 20 mg/l and by increasing sds concentration to 40 mg/l the removal efficiency of cd(ii) ion was deceased to (60.2%) due to competition between the metal-collector complex and free collector ions for bubble surface sites at excessive collector amount as well as micelle formation , y = 0.9991x + 0.0707 r² = 0.9997 0 10 20 30 40 50 60 70 80 90 100 0 10 20 30 40 50 60 70 80 90 100 p e d ic te d d a ta expeimental data exp-pre linear (exp-pre) 0 10 20 30 40 50 60 70 80 90 0 5 10 15 20 25 r e m o v a l e ff ic ie n cy , % time, min sds ctab 0 10 20 30 40 50 60 70 80 90 0 5 10 15 20 25 r e m o v a l e ff ic ie n cy , % time , min ph3 ph4 ph5 ph6 pre ph3 pre ph4 pre ph5 a. i. alwared et al. / iraqi journal of chemical and petroleum engineering 20,2 (2019) 1 9 5 the potential toxicity of residuals amounts of collector in the effluent and cost [23], also this figure confirms that the ann model could be effectively predicting the experimental results. to theoretically examine, if the amount of sds represent the optimum value for highly removal efficiency, ann model was used at different concentrations of sds was varied around the best value (15, 18, 20, 22, 25, 28, 30 and 35 mg/l) as shown in fig. 10. it can be seen from this figure that there is a good agreement between the experimental data and the predicted data, in addition through ann model, the optimum value of sds concentration was 18 mg/l. table 3 shows that, the removal rate constants increased with increasing sds concentration. the result is in agreement with the finding of [26]. fig. 9. influence of sds on the cd(ii) ions removal efficiency fig. 10. removal efficiency predicted by ann model at different sds concentration table 3. rate constant at various sds concentrations sds concentration sds10 sds20 sds40 k×10 2 (min -1 ) 1.883 4.505 1.155 4.5. influence of flow rate different air flow rate (100, 200 and 250cm 3 /min) were tested to examine their effect on the removal efficiency of cd(ii) ion in the microbubble dispersed air flotation column was investigated. the other parameters were remained constants (ph=5, cadmium conc. = 40 mg/ l and sds = 10 mg/l), fig. 11 indicated that the removal efficiency was highly affected by the gas flow rate, the large number of small bubbles leads to increase the surface area available for metalcollector adsorption. by increasing gas flowrate, the removal efficiency increased. increasing gas flow rate causes early bubble detachment, large fluid activities (stress) at the bottom section and bubble coalescence and (mostly) break up [27] also, these results are in good agreement with the proposed ann model. to theoretically examine, if this value represents the best flow rate for maximum removal efficiency, fig. 12 presents the influence of different air flow rate around the best value on the removal rate of cd(ii) ions (2, 2.2, 2.5 , 2.7 and 3 cm 3 /min) it can be noticed from this figure that 2.7 cm 3 /min was the best predicted value. table 4 presents the removal rate constants (k) at different air flow rate, which shows that the( k) increased by gas flow rate increased. fig. 11. removal efficiency of cd(ii) ions at different air flow rate 0 10 20 30 40 50 60 70 80 90 100 0 5 10 15 20 25 r e m o v a l e ff ic ie n cy ,% time, min sds0 sds10 sds20 sds40 presds0 presds1 0 50 55 60 65 70 75 80 85 90 95 100 10 12 14 16 18 20 22 24 26 28 30 32 34 36 r e m o v a l e ff ic ie n cy , % sds concentration , mg/l 0 10 20 30 40 50 60 70 80 90 100 -1 1 3 5 7 9 11 13 15 17 19 21 23 25 r e m o v a l e ff ic ie n cy , % time, min q=100cm3/m in q=200cm3/m in q=250cm3/m in preq=100 preq=200 preq=250 a. i. alwared et al. / iraqi journal of chemical and petroleum engineering 20,2 (2019) 1 9 6 fig. 12. predicted removal efficiency at different air flow rate table 4. flotation kinetic at different air flow rates air flow rate(cm 3 /min) q=100 q=200 q=250 k×10 2 (min -1 ) 2.375 4.456 9.156 4.6. influence of initial concentration of cd(ii) ions three different initial cd(ii) ions concentrations were tested in this study (40 , 80 and 120 mg/l) while keeping other parameters constant (ph=5, sds = 10 mg/l and flow rate = 250 cm3/min) and their results presented in fig. 13, which indicating that the removal rate decreased with increasing cd(ii) ions concentration from 40mg/l to 120mg/l , owing to the fact that the floatability of cd(ii) ions reduced at their higher concentrations, the removal efficiency decreased from (92.3%) to (63%) for cd(ii) ions by increasing the initial metal ions concentration from 40 to 120 mg/l respectively at 15min. this is in agreement with the finding of [28][22], they concluded that by increasing metal ion concentration ,more collector are required at low ph for the same percent removal. so, the removal efficiency decreased at higher cd(ii) ions concentrations, also this figure confirms that the neural network model could be effectively predicting the experimental results. to theoretically examine this value for maximum removal efficiency, fig. 14 present the influence of different initial metal concentration around the optimum value (30, 35, 40, 45, 50, and 55) on the removal rate of cd(ii) ions using ann model , the ann model reveals 40 mg/l concentration was the best predicted value as it shows an agreement between predicted and results. a concentration of (40 mg/l) was predicted to be the best value. table 5 shows higher removal of cd(ii) ions occurred at the lowest initial concentration. fig. 13. removal efficiency as a function of initial metal ions concentration fig. 14. effect of cd(ii) ions concentration predicted around the best value on the removal efficiency table 5. kinetic flotation at different initial cd(ii) ions concentration co=40mg/l co=80 mg/l co=120 mg/l k×10 2 (min -1 ) 9.256 3.998 2.994 4.8. influence ionic strength fig. 15 shows the influence of nacl addition to the cadmium ions removal at different concentration (0, 10 and 25 mg/l), while all other parameters were kept constant (ph5, initial cadmium ions concentration40mg/l, flow rate 250cm 3 /min and sds concentration 10mg/l), the results of this figure explain that the removal rate reduced significantly with increasing nacl concentration. the reduction of cadmium ion in the presence of nacl could be attributed to the competitive effect between cd(ii) ions and na from the salt so the metal ions cannot find enough sds surfactant molecules to attach to [29], this is in agreement with the finding of[27] fig.15 also, shows the agreement between the experimental data and the predicted. 60 65 70 75 80 85 90 95 100 1.5 1.7 1.9 2.1 2.3 2.5 2.7 2.9 3.1 r e m o v a l e ff ic ie n cy , % flow rate 0 10 20 30 40 50 60 70 80 90 100 0 5 10 15 20 25 r e m o v a l e ff ic ie n cy , % time , min conc.=40mg /l conc.=80mg /l conc.120mg /l pre40 pre80 80 82 84 86 88 90 92 94 20 25 30 35 40 45 50 55 60 r e m o v a l e ff ic ie n cy , % initiai concentration , mg/l a. i. alwared et al. / iraqi journal of chemical and petroleum engineering 20,2 (2019) 1 9 7 fig. 15. effect of salt concentration on the cd(ii) ions 4.9. turbidity an important aspect of water quality is turbidity, it is estimated as the liquid cloudiness and caused by colloidal matter and suspends like clay, silt, inorganic matter and finely divided organic, plankton and other microorganisms [30]. fig. 16 shows that the efficiency of turbidity removal was increased from 90.23% to 96.88% by increasing air flow rate from 100 to 250cm 3 /min .so, it is concluded that flow rate has a significant influence in reducing turbidity due to increase the bubble rise velocity [31]. fig. 16. removal of turbidity at different flow rate 4.10. analysis of sensitivity garson suggested an equation assess the relative importance of the input variables depends upon the connection weights partitioning, as can be seen in eq. (4) [31].                                                   nik k nhm m ho mnni k ih km ih km nhm m ho mnni k ih km ih jm w w w w w w ij 1 1 1 1 1 (4) where; ij is the relative importance of the jth input variable on the output variable, ni and nh are the numbers of input and hidden neurons, respectively, the superscripts i, h and o refer to input, hidden and output layers, respectively, ws are connection weights, and subscripts k , m and n refer to input, hidden and output neurons, respectively. fig. 17 presents that the most important parameter is ph with relative importance of 25.13%.it sensitivity analysis varied depending on reactive material and the type of contaminant [17]. fig. 17. piechart for relative importance predicted using ann model 5conclusion in this work, ann model was used to examine the performance of microbubble dispersed air floatation method for the removing of cd (ii) ions from simulated wastewater. the maximum correlation coefficient was more than 0.999 which confirmed exact and powerful results experimentally. hidden neuron of lma were 11neurons having rmse 1.062. the sensitivity analysis showed that the reactions were influenced by the ph, input concentration of cd (ii) ions, sds surfactant concentration, flow rate and ionic strength but ph appeared the most influence parameters with relative importance of 25.13 %. the maximum removal efficiency achieved was 92.3% at ph=5, 20mg/l initial cd(ii) concentration, 10mg/l surfactant concentration and 250cm 3 /cm 3 flowrate at 15min contact time . the kinetic flotation order for cd (ii) ions almost first order and the removal rate constant (k) increases with decreasing the initial metal concentration and increasing flow rate. references [1] ksakas, a., tanji, k., el bali b and taleb, m., a. kherbeche, (2018), “removal of cu (ii) ions from aqueous solution by adsorption using natural clays: kinetic and thermodynamic studies”, j. mater. environ.sci.,9,(3).:1075-1085. 0 10 20 30 40 50 60 70 80 90 100 0 10 20 30 r e m o v a l e ff ic e in cy time , min without nacl 10mg/l 25mg/l nacl pre0 pre10 pre25 0 5 10 15 20 25 30 0 3 6 9 12 15 18 21 t u b id it y , n t u time, min q=1 q=2 q=2.5 https://www.researchgate.net/publication/323385122_removal_of_cu_ii_ions_from_aqueous_solution_by_adsorption_using_natural_clays_kinetic_and_thermodynamic_studies. https://www.researchgate.net/publication/323385122_removal_of_cu_ii_ions_from_aqueous_solution_by_adsorption_using_natural_clays_kinetic_and_thermodynamic_studies. https://www.researchgate.net/publication/323385122_removal_of_cu_ii_ions_from_aqueous_solution_by_adsorption_using_natural_clays_kinetic_and_thermodynamic_studies. https://www.researchgate.net/publication/323385122_removal_of_cu_ii_ions_from_aqueous_solution_by_adsorption_using_natural_clays_kinetic_and_thermodynamic_studies. https://www.researchgate.net/publication/323385122_removal_of_cu_ii_ions_from_aqueous_solution_by_adsorption_using_natural_clays_kinetic_and_thermodynamic_studies. a. i. alwared et al. / iraqi journal of chemical and petroleum engineering 20,2 (2019) 1 9 8 [2] mohammed, a. a. ,2015, „‟ biosorption of lead, cadmium, and zinc onto sunflower shell: equilibrium, kinetic, and thermodynamic studies‟‟, iraqi journal of chemical and petroleum engineering ,16(1) :91105. [3] abas, s. n. a., ismail, m. h. sh., kamal, m. l., and izhar, sh., 2013, "adsorption process of heavy metals by low-cost adsorbent : a review", world applied sciences journal, 28(11): 1518–1530. [4] jimoh, o.ti, mercy, t. b., musa m. and idowu, o. f., (2014), development of low cost adsorbent from cow horn for the biosorption of mn (ii), ni (ii) and cd (ii) ion from aqueous solution, “research journal of applied sciences, engineering and technology 7(1): 9-17. [5] oteroa, m., rozada f., morán a., calvo l.f., garcía a.i., 2009. removal of heavy metals from aqueous solution by sewage sludge based sorbents: competitive effects, desalination, 239 : 46–57. [6] algureiri a. h. and abdulmajeed, y. r., 2016,removal of heavy metals from industrial wastewater by using ro membrane , iraqi journal of chemical and petroleum engineering vol.17 no.4 : 125136. [7] ohnari h. waste water purification in wide water area by use of micro-bubble techniques. jpn journal multiphase flow1997;11:263– 266(injapanese). [8] jyoti kk, pandit ab. water disinfection by acoustic and hydrodynamic cavitation. biochem. eng. j 2001; 7: 201 – 212 [9] terasaka k, shinpo y. separation of fine particles suspended in water using microbubble flotation. jpn j multiphase flow 2007; 21: 77 – 83 (in japanese). [10] ketkar d.r, mallikarjunan r, venkatachalam s. electroflotation of quartz fines. int j miner process 1991; 31: 127 – 138. [11] liu s, wang q, ma h, huang p, li j, kikuchi t. effect of micro-bubbles on coagulation flotation process of dyeing wastewater. sep purif technol 2010; 71: 337 – 346. [12] rodrigues, t. and rubio, j, (2007), “review article:daf–dissolved air flotation: potential applications in the mining and mineral processing industry”, int. j. miner. process82: 1–13, [13] ghazy, s. e, el-morsy, s.m, and ragab, a. h., 2008,"ion flotation of copper ( ii ) and lead ( ii ) from environmental water samples", j. appl. sci. environ. manage, 12(3): 75–82. [14] mohammed, a. a., ebrahim, sh. e., and alwared, a. i., (2013), "flotation and sorptive flotation methods for removal of lead ions from wastewater using sds as surfactant and barley husk as biosorbent", journal of chemistry, id 413948:16. [15] hoseinian, f.s., rezai, b.; kowsari, e.; safari, m. kinetic study of ni(ii) removal using ion flotation: effect of chemical interactions. miner. eng. 2018, 119, 212–221. [16] mnatia, k. h. and abdul hadi, h. , 2018, „‟ prediction of penetration rate and cost with artificial neural network for alhafaya oil field‟‟, iraqi journal of chemical and petroleum engineering ,19(4) : 12 – 27. [17] alwared, a. i., (2013), "artificial neural network approach for prediction lead ions removable from wastewater by flotation method", journal of general secretary of arab engineering colleges society, association of arab universities union, 20(1). [18] mustafa y. a. , jaid g. m., alwared a. i. , ebrahim m. (2014), "the use of artificial neural network (ann) for the prediction and simulation of oil degradation in wastewater by aop environmental", science and pollution research 21(12). [19] jaeel a. j., al-wared a.i, ismail z.z.,(2016), " prediction of sustainable electricity generation in microbial fuel cell by neural network: effect of anode angle with respect to flow direction", journal of electroanalytical chemistry 767 : 56–62. [20] nasrullaha a. , bhata a.h., isab m.h. , danishc m.,abdul naeemd, muhammade n. and khan t., (2017), "efficient removal of methylene blue dye using mangosteen peel waste: kinetics, isotherms and artificial neural network (ann) modeling", desalination and water treatment ,86 . [21] abdulhussein, s. a., (2018) ,”removal of cu +2 and ni +2 from aqueous solution using flotation and sorptive flotation with application of artificial neural network, m.sc. thesis, collage of engineering, university of baghdad, iraq. [22] mohammed a.a. abed , f.i., (2011), “removal of copper ion from wastewater by flotation” , journal of engineering, 17(6).1483-1491. [23] gupta, a. k., and yan, d. s., 2006,"mineral processing design and operation", elsevier b.v., 565567. [24] sulaymon, a., and mohammed, a.,(2010), ''separation and hydrodynamic performance of air – kerosene-water system by bubble column'', international journal of chemical reactor engineering, vol. 8, :1-15 [25] zouboulis, a. i., and matis, k. a. 1987, "ion flotation in environmental technology", chemosphere, 16(2-3), pp.623-631. [26] muhaisn, l.f., 2014, "competitive removal of heavy metal ions from simulated wastewater by sorptive flotation using punica granatum", m.sc. thesis, college of engineering, university of baghdad, iraq. [27] zouboulis, a. i., matis, k. a., and stalidis, g. a., 1990," parameters influencing flotation in removal of metal ions", international journal of environmental studies, 35:183-196. [28] choi, s.j., and kim, k.h., the improvement of the removal efficiency of foam flotation by synergistic effect of mixed surfactant solutions, environment technology, 19, 1151-1156(1998). https://www.iasj.net/iasj?func=fulltext&aid=99435 https://www.iasj.net/iasj?func=fulltext&aid=99435 https://www.iasj.net/iasj?func=fulltext&aid=99435 https://www.iasj.net/iasj?func=fulltext&aid=99435 https://www.iasj.net/iasj?func=fulltext&aid=99435 https://www.idosi.org/wasj/wasj28(11)13/7.pdf https://www.idosi.org/wasj/wasj28(11)13/7.pdf https://www.idosi.org/wasj/wasj28(11)13/7.pdf https://www.idosi.org/wasj/wasj28(11)13/7.pdf https://www.researchgate.net/publication/287843911_development_of_low_cost_adsorbent_from_cow_horn_for_the_biosorption_of_mn_ii_ni_ii_and_cd_ii_ion_from_aqueous_solution https://www.researchgate.net/publication/287843911_development_of_low_cost_adsorbent_from_cow_horn_for_the_biosorption_of_mn_ii_ni_ii_and_cd_ii_ion_from_aqueous_solution https://www.researchgate.net/publication/287843911_development_of_low_cost_adsorbent_from_cow_horn_for_the_biosorption_of_mn_ii_ni_ii_and_cd_ii_ion_from_aqueous_solution https://www.researchgate.net/publication/287843911_development_of_low_cost_adsorbent_from_cow_horn_for_the_biosorption_of_mn_ii_ni_ii_and_cd_ii_ion_from_aqueous_solution https://www.researchgate.net/publication/287843911_development_of_low_cost_adsorbent_from_cow_horn_for_the_biosorption_of_mn_ii_ni_ii_and_cd_ii_ion_from_aqueous_solution https://www.researchgate.net/publication/287843911_development_of_low_cost_adsorbent_from_cow_horn_for_the_biosorption_of_mn_ii_ni_ii_and_cd_ii_ion_from_aqueous_solution https://www.sciencedirect.com/science/article/pii/s0011916409000204 https://www.sciencedirect.com/science/article/pii/s0011916409000204 https://www.sciencedirect.com/science/article/pii/s0011916409000204 https://www.sciencedirect.com/science/article/pii/s0011916409000204 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/239 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/239 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/239 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/239 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/239 %5b1%5d%09https:/www.sciencedirect.com/science/article/pii/s0011916409000204 %5b1%5d%09https:/www.sciencedirect.com/science/article/pii/s0011916409000204 %5b1%5d%09https:/www.sciencedirect.com/science/article/pii/s0011916409000204 %5b1%5d%09https:/www.deepdyve.com/lp/elsevier/water-disinfection-by-acoustic-and-hydrodynamic-cavitation-fa0vrkusnu %5b1%5d%09https:/www.deepdyve.com/lp/elsevier/water-disinfection-by-acoustic-and-hydrodynamic-cavitation-fa0vrkusnu %5b1%5d%09https:/www.deepdyve.com/lp/elsevier/water-disinfection-by-acoustic-and-hydrodynamic-cavitation-fa0vrkusnu https://www.jstage.jst.go.jp/article/jjmf/21/1/21_1_77/_article https://www.jstage.jst.go.jp/article/jjmf/21/1/21_1_77/_article https://www.jstage.jst.go.jp/article/jjmf/21/1/21_1_77/_article https://www.sciencedirect.com/science/article/abs/pii/0301751691900098 https://www.sciencedirect.com/science/article/abs/pii/0301751691900098 https://www.sciencedirect.com/science/article/abs/pii/0301751691900098 https://www.sciencedirect.com/science/article/pii/s1383586610000055 https://www.sciencedirect.com/science/article/pii/s1383586610000055 https://www.sciencedirect.com/science/article/pii/s1383586610000055 https://www.sciencedirect.com/science/article/pii/s1383586610000055 https://www.sciencedirect.com/science/article/abs/pii/s0301751606002213 https://www.sciencedirect.com/science/article/abs/pii/s0301751606002213 https://www.sciencedirect.com/science/article/abs/pii/s0301751606002213 https://www.sciencedirect.com/science/article/abs/pii/s0301751606002213 https://www.ajol.info/index.php/jasem/article/view/55499 https://www.ajol.info/index.php/jasem/article/view/55499 https://www.ajol.info/index.php/jasem/article/view/55499 https://www.ajol.info/index.php/jasem/article/view/55499 https://www.hindawi.com/journals/jchem/2013/413948/ https://www.hindawi.com/journals/jchem/2013/413948/ https://www.hindawi.com/journals/jchem/2013/413948/ https://www.hindawi.com/journals/jchem/2013/413948/ https://www.hindawi.com/journals/jchem/2013/413948/ https://www.researchgate.net/publication/323798614_kinetic_study_of_niii_removal_using_ion_flotation_effect_of_chemical_interactions. https://www.researchgate.net/publication/323798614_kinetic_study_of_niii_removal_using_ion_flotation_effect_of_chemical_interactions. https://www.researchgate.net/publication/323798614_kinetic_study_of_niii_removal_using_ion_flotation_effect_of_chemical_interactions. https://www.researchgate.net/publication/323798614_kinetic_study_of_niii_removal_using_ion_flotation_effect_of_chemical_interactions. https://www.iasj.net/iasj?func=fulltext&aid=154988 https://www.iasj.net/iasj?func=fulltext&aid=154988 https://www.iasj.net/iasj?func=fulltext&aid=154988 https://www.iasj.net/iasj?func=fulltext&aid=154988 https://www.iasj.net/iasj?func=fulltext&aid=154988 https://www.researchgate.net/publication/259874631_artificial_neural_network_approach_for_modeling_of_adsorption_of_ni_ii_and_cr_vi_ions_simultaneously_present_in_aqueous_solution_using_adsorbent_synthesized_from_aegel_marmelos_fruitshell_and_syzygium https://www.researchgate.net/publication/259874631_artificial_neural_network_approach_for_modeling_of_adsorption_of_ni_ii_and_cr_vi_ions_simultaneously_present_in_aqueous_solution_using_adsorbent_synthesized_from_aegel_marmelos_fruitshell_and_syzygium https://www.researchgate.net/publication/259874631_artificial_neural_network_approach_for_modeling_of_adsorption_of_ni_ii_and_cr_vi_ions_simultaneously_present_in_aqueous_solution_using_adsorbent_synthesized_from_aegel_marmelos_fruitshell_and_syzygium https://www.researchgate.net/publication/259874631_artificial_neural_network_approach_for_modeling_of_adsorption_of_ni_ii_and_cr_vi_ions_simultaneously_present_in_aqueous_solution_using_adsorbent_synthesized_from_aegel_marmelos_fruitshell_and_syzygium https://www.researchgate.net/publication/259874631_artificial_neural_network_approach_for_modeling_of_adsorption_of_ni_ii_and_cr_vi_ions_simultaneously_present_in_aqueous_solution_using_adsorbent_synthesized_from_aegel_marmelos_fruitshell_and_syzygium https://www.researchgate.net/publication/259874631_artificial_neural_network_approach_for_modeling_of_adsorption_of_ni_ii_and_cr_vi_ions_simultaneously_present_in_aqueous_solution_using_adsorbent_synthesized_from_aegel_marmelos_fruitshell_and_syzygium https://www.ncbi.nlm.nih.gov/pubmed/24595749 https://www.ncbi.nlm.nih.gov/pubmed/24595749 https://www.ncbi.nlm.nih.gov/pubmed/24595749 https://www.ncbi.nlm.nih.gov/pubmed/24595749 https://www.ncbi.nlm.nih.gov/pubmed/24595749 https://www.ncbi.nlm.nih.gov/pubmed/24595749 https://www.sciencedirect.com/journal/journal-of-electroanalytical-chemistry/vol/767/suppl/c https://www.sciencedirect.com/journal/journal-of-electroanalytical-chemistry/vol/767/suppl/c https://www.sciencedirect.com/journal/journal-of-electroanalytical-chemistry/vol/767/suppl/c https://www.sciencedirect.com/journal/journal-of-electroanalytical-chemistry/vol/767/suppl/c https://www.sciencedirect.com/journal/journal-of-electroanalytical-chemistry/vol/767/suppl/c http://www.deswater.com/dwt_abstracts/vol_86/86_2017_191.pdf http://www.deswater.com/dwt_abstracts/vol_86/86_2017_191.pdf http://www.deswater.com/dwt_abstracts/vol_86/86_2017_191.pdf http://www.deswater.com/dwt_abstracts/vol_86/86_2017_191.pdf http://www.deswater.com/dwt_abstracts/vol_86/86_2017_191.pdf http://www.deswater.com/dwt_abstracts/vol_86/86_2017_191.pdf https://www.iasj.net/iasj?func=search&query=au:%22farah%20i.%20abed%20%22&formquery=au:%22farah%20i.%20abed%20%22&uilanguage=en https://www.iasj.net/iasj?func=search&query=au:%22farah%20i.%20abed%20%22&formquery=au:%22farah%20i.%20abed%20%22&uilanguage=en https://www.iasj.net/iasj?func=search&query=au:%22farah%20i.%20abed%20%22&formquery=au:%22farah%20i.%20abed%20%22&uilanguage=en https://www.researchgate.net/publication/41764919_separation_and_hydrodynamic_performance_of_air-kerosene-water_system_by_bubble_column https://www.researchgate.net/publication/41764919_separation_and_hydrodynamic_performance_of_air-kerosene-water_system_by_bubble_column https://www.researchgate.net/publication/41764919_separation_and_hydrodynamic_performance_of_air-kerosene-water_system_by_bubble_column https://www.researchgate.net/publication/41764919_separation_and_hydrodynamic_performance_of_air-kerosene-water_system_by_bubble_column https://www.researchgate.net/publication/41764919_separation_and_hydrodynamic_performance_of_air-kerosene-water_system_by_bubble_column https://www.sciencedirect.com/science/article/pii/004565358790275x https://www.sciencedirect.com/science/article/pii/004565358790275x https://www.sciencedirect.com/science/article/pii/004565358790275x https://www.tandfonline.com/doi/abs/10.1080/00207239008710564 https://www.tandfonline.com/doi/abs/10.1080/00207239008710564 https://www.tandfonline.com/doi/abs/10.1080/00207239008710564 https://www.tandfonline.com/doi/abs/10.1080/00207239008710564 https://www.tandfonline.com/doi/abs/10.1080/09593331908616775 https://www.tandfonline.com/doi/abs/10.1080/09593331908616775 https://www.tandfonline.com/doi/abs/10.1080/09593331908616775 https://www.tandfonline.com/doi/abs/10.1080/09593331908616775 a. i. alwared et al. / iraqi journal of chemical and petroleum engineering 20,2 (2019) 1 9 9 [29] asano, t., burton, f.l., leverenz, h.l., tsuchihashi, r., and tchobanoglous, g., 2007, "water reuse: issues, technologies, and applications", metcalf and eddy/aecom. mcgraw-hill, usa. [30] hameed, n. a., 2016, "removal of lead, copper, and nickel from aqueous solutions by integrated biosorption flotation technique", m.sc. thesis, college of engineering, university of baghdad, iraq. [31] aleboyeh, a., kasiri, m. b., olya, m. e., aleboyeh, h., 2008, "prediction of azo dye decolorization by uv/h2o2 using artificial neural networks", dyes and pigments, 77:pp.288-294. ل التعويم باستخدام الفقاعات المايكروية الزالة ايونات الكادميوم من المحاليل المائية: مودي الشبكة العصبية االصطناعية والتعويم الحركي الخالصة تيدف ىذه الدراسة الى تطبيق تقنية دقائق اليواء المتناىية الصغر في طريقة تعويم اليواء إلزالة أيونات و 5و 4و 3الكادميوم من المحاليل المائية وذلك من خالل دراسة مجموعو من المتغيرات :الرقم الييدروجيني ) و 15و 10و 5و 2ممغم / لتر( وقت االتصال ) 120و 80و 40( والتركيز األولي لأليونات الكادميوم )6 من أجل ايجاد أفضل ممغم / لتر( 40و 20و 10دقيقة( ، تركيز المواد الخافضة لمشد السطحي ) 20 فعالة جًدا في إزالة أيونات الظروف وتشير النتائج التجريبية إلى أن دقائق اليواء المتناىية الصغر كانت كمادة خافضة لمشد السطحي في عممية التعويم.وبكفاءة ctab أكثر فعالية من sdsالكادميوم وأن مادة ممغم / لتر (و 20) sds، وتركيز مادة 5دقيقة عند دالة حامضية 15٪ تحققت خالل 92.3عالية بمغت .مغم/لتر(م4/ دقيقة وبتركيز اولي ) 3سم 250معدل تدفق من اجل التنبؤ بازالة ايونات الكادميوم من المحاليل المائية خالل annتطبيق برنامج كما تضمنت الدراسة والبيانات التجريبية ann بين مخرجات 0.9997طبقة من الخاليا العصبية المخفية ، مع معامل ارتباط 11 ٪( ىو اكثر معامل يؤثر عمى العممية 25.13) ومن خالل تحميل الحساسية تبين أن الرقم الييدروجيني كماتوصمت الدراسة الى ان كان موديل يمثل النتائج العممية ىو موديل التعويم الحركي من الدرجة الثانية ويزيد .ثابت معدل إزالة مع انخفاض تركيز المعادن األولي .، معدل التعويم الحركي ann: أيونات الكادميوم ، التعويم ، دقائق اليواء المتناىية الدقة ، لدالةالكممات ا http://ssu.ac.ir/cms/fileadmin/user_upload/daneshkadaha/dbehdasht/markaz_tahghighat_olom_va_fanavarihaye_zist_mohiti/e_book/wastewater_reuse/water_reuse/untitled14.pdf.pdf http://ssu.ac.ir/cms/fileadmin/user_upload/daneshkadaha/dbehdasht/markaz_tahghighat_olom_va_fanavarihaye_zist_mohiti/e_book/wastewater_reuse/water_reuse/untitled14.pdf.pdf 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raidhani73@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. evaluation the effect of velocity and temperature on the corrosion rate of crude oil pipeline in the presence of co2/h2s dissolved gases haider hadi jasim chemical engineering department, college of engineering, basrah university, basrah, iraq abstract in this paper investigate the influences of dissolved co2/h2s gases, crude oil velocity and temperature on the rate of corrosion of crude oil transmission pipelines of maysan oil fields southern iraq. the potentiostatic corrosion test technique was conducted into two types of carbon steel pipeline (materials api 5l x60 and api 5l x80). the computer software ece electronic corrosion engineer was used to predict the influences of co2 partial pressure, the composition of crude oil, flow velocity of crude oil and percentage of material elements of carbon steel on the rate of corrosion. as a result, the carbon steel api 5l x80 indicates good and appropriate resistance to corrosion compared to carbon steel api 5l x60. the rate of corrosion acquired from the test in flow conditions is most significant than that in static conditions. the crude oil from noor field has the largest value of corrosion rate, while the crude oil from halfaya field has the lower value; other crude oils have moderate values. the dissolved co2/h2s gases contribute by a low degree in internal pipeline corrosion because of the small concentrations. keywords: co2/h2s corrosion, crude oil velocity, chloride salts, potentiostatic test, carbon steel received on 02/12/2018, accepted on 13/03/2019, published on 30/06/1029 https://doi.org/10.31699/ijcpe.2019.2.6 1introduction the pipelines are used to transport a crude oil or its products from one location to every other. depending on the purpose, the oil pipelines can be labeled into three categories. first, gathering lines, this type has a small diameter and is used in short distances to handle crude oil. second, transportation pipelines or feeders have a diameter greater than gathering pipelines and pass the oil product from storage or refinery units to distribution pipelines. thirdly, a transmission pipeline, this type has the largest diameter and used to transport various grades of crude oil from the production area to the ultimate consumption area ‎[1]. crude oil is a complex mixture contains different impurities which effect on the corrosion rate of metal such as sulfur, water, various dissolved ions (na + , k + , ca +2 , , cl …etc), organic acids, co2 and h2s gases. corrosion of carbon steel by co2 gas is a significant problem in the crude oil transportation pipelines; co2 gas dissolves in the water at different extents depending on temperature and pressure, which producing corrosive species. these species, besides the conventional salinity, producing the weak carbonic acid (h2co3), bicarbonate ( ) and carbonate ( ) and becomes as driving the corrosion reactions depending on their concentrations and on ph levels ‎[2], ‎[3]. the electronic corrosion engineer (ece) software is a good new tool that provides a useful approach for estimating the rate of corrosion of co2 and h2s dissolved gases on different types of carbon steel material used in a pipeline and tubes for crude oil transportation. various parameters that influence the corrosion in the presence of was taken by the ece program include the co2 partial pressure, temperature, and the crude oil velocity ‎[4]. the potentiostatic technique is one of the best electrochemical techniques used in corrosion testing for a quick time. this method includes the application of anodic discrete potential values in the scope of mv to the immersed specimen in a solution for a fixed time, and the potential-log current density curve is obtained. analysis of the curve using tafel technique can result in the corrosion current, which is used to calculate the value of corrosion rate ‎[5], ‎[6]. the problems of co2 corrosion and its control of oil pipelines have been reported in many studies. vuppu et al. ‎[7] studied the influence of temperature on the rate of corrosion and forms of protective carbonate layer on carbon steel pipelines at various crude oil velocities and oil-water mixtures. they show that both increases the temperatures and oil velocities have negative effect on protective carbonate layer formed on the steel surface. xu et al. ‎[8] review the corrosion mechanism of co2, h2s and so2 of the inner side of oil pipelines. https://doi.org/10.31699/ijcpe.2019.2.6 h. h. jasim / iraqi journal of chemical and petroleum engineering 20,2 (2019) 41 50 24 their results show that the corrosion occurs as a result of the reactions between the crude oil compounds and the inner side of the pipelines through crude oil transport. prakash et al. ‎[9] study the internal corrosion of the api 5l grade-b carbons steel metal of kuwait export crude oil pipeline network. results of their study showed that in addition to the microbial effects, corrosion problems are caused by the effect of co2 and h2s gases. saleh et al. ‎[10] studied the corrosion rate of carbon steel pipe under various conditions including salinity, temperature velocity for both single and multiple flows of crude oil. their result’s shows that for a single phase flow, the rate of metal corrosion in the nacl brine solution is larger than in the multiphase flow (nacl brine co2 kerosene). wang et al. ‎[11] reviewed and summarized the methods of measuring thecorrosion in oil-brine mixed conditions. they show that the effects of water and wetting behavior in corrosion process were very impressive in the case of flow conditions. muhammed ‎[12] investigated the effects of soil properties contains by crude oil on the corrosion rate of api x70 steel pipeline used in oil transmissions from iraq to turkey. the results showed that the soil’s moisture content and ph had the most significant impact on the corrosion process. mobbassar et al. ‎[13] demonstrated the factor influencing corrosion in inner oil pipeline made from low carbon alloy steel. they showed that analyzing the final corrosion product can help to select the most efficient and economical materials resistant to corrosion in the co2 environment. mursalov ‎[14] review the corrosion mechanism of h2s, the effect of ph value and temperature on the corrosion rate in the oil industry. the results of studies show that various oxides and chemical compounds are formed on the metal surface depending on the h2s concentration, ph value, and temperature and co2 presence in the oil solutions. cedeno et al. ‎[15] study by using the electrochemical measurements the effects of fluid speed, temperature and oil content on the corrosion rate of the aisi-sae 1020 steel used in the petroleum transportation pipelines under a saturated co2 gas. the results show that crude oil has the most significant effect of in the rate of corrosion of steel and increased as temperature and fluid velocity increased. kolawole et al. ‎[16] give a comprehensive review of co2 and h2s corrosion problems in api 5l steel pipeline and the proper methods to control the corrosion problems. they showed that the primary causes of corrosion in oil and gas pipelines are the presence of water together with acid gases (co2 and h2s). this research aims to study the corrosion phenomenon of two types of carbon steel pipeline api 5l x60 and api 5l x80 used for the transport of crude oil through the use of potentiostatic corrosion test method. engineering corrosion software version 5.1 was used to calculate the rate of co2/h2s corrosion of crude oil pipelines underneath different water fractions, temperature, velocity, and pressure of crude oil. 2experimental methods 2.1. pipeline materials and specimens preparation in iraq, there are two networks of pipelines extending over a distance of 300 km and transport crude oil from maysan oil fields (buzerkan, halfaya and faqa oil fields) to the port of basrah southern iraq. the networks pipeline materials are seamless carbon steels api 5l x80 and api 5l x60 and the chemical compositions are given in table 1 and table 2, respectively. the mechanical properties of these two materials are listed in table 3. the api 5l x80 pipelines have a diameter of 122 cm, and the api 5l x60 have a diameter of 61 cm. both of these pipelines have a thickness of 14 mm. table 1. chemical composition (wt. %) of api 5l x80 carbon steel ‎[17] metals % metals % c 0.08 al 0.03 si 0.26 mo 0.27 mn 1.75 ni 0.22 p 0.011 nb 0.07 s 0.0005 fe balance table 2. chemical composition (wt. %) of api 5l x60 carbon steel ‎[18] metals % metal % c 0.007 al 0.008 si 0.22 cu 0.013 mn 1.63 ti 0.010 p 0.01 v 0.072 s 0.005 nb 0.052 cr 0.011 n 0.008 ni 0.011 mo 0.228 table 3. mechanical properties of api 5l x80 and api 5l x60 carbon steel ‎[17], ‎[18] grade yield strength mpa (min.) tensile strength mpa elongation % (min.) x80 555 min. 625700 20 min. x60 541 min. 627 27 min. the test specimens were prepared by cutting it in a cylindrical shape from a plate pipe material with a diameter of 1 cm and a thickness of 5 mm. according to astm g1-03 ‎[19] and astm g5997 ‎[20], the specimens were sequentially polished using silicon abrasive papers of 160, 180 and 200 grades, then washed with distilled water and dried with hot air in ambient conditions. the specimens are shown in fig. 1. for each test, a new specimen was used for testing, a total of 50 specimens were used. h. h. jasim / iraqi journal of chemical and petroleum engineering 20,2 (2019) 41 50 24 fig. 1. specimens for potentiostatic test: ax60 carbon steel bx80 carbon steel 2.2. crude oil samples analysis the test oil samples used in this study were obtained from different oil fields in maysan province (noor, buzerkan, halfaya, abu-gharab, faqa1 and faqa2) southern iraq. the material compositions of crude oils are analyzed in nahr umer laboratory of the south oil company and are listed in table 4. the physical properties of crude oils obtained from field’s laboratory are summarized in table 5. table 4. compositions of various crude oils materials fields noor bazerkan faqa1 faqa2 halfaya abugarab iron ppm wt. 1.1 2.2 3.76 3.9 2.8 1.77 copper ppm wt. 6.1 3 5.1 5.2 3.6 1.3 vanadium ppm wt. 30 32 31 31 34 29 nickel ppm wt. 8.7 10 11 11.6 7.1 11 cadmium ppm 0.78 0.41 0.52 0.64 0.23 0.8 aluminum ppm wt. 0.44 0.13 0.31 0.33 0.16 0.27 manganese ppm wt. 0.30 0.17 0.22 0.22 0.27 0.10 sulfur % 4.6 5.12 3.89 3.9 4.85 4.86 water content % 2.4 1.85 1.96 2.05 2 2.3 nacl ppm 44 31.5 24.4 22.3 14 11 h2s (g) ppm 0.32 0.21 0.42 0.40 0.49 0.45 co2 (g) ppm 0.96 0.41 0.67 0.77 0.57 0.83 table 5. physical properties of crude oils properties fields noor bazergan faqa1 faqa2 halfaya abu -gharab api 16 24.7 22.5 23.2 27 25 asphaltenes % 13.8 13.2 10.5 12.6 15.1 14.8 specific gravity at 20 o c 0.8792 0.8901 0.9048 0.912 8 0.8835 0.8584 kinematics viscosity cst at 20 o c 33.5 45 40.1 33.6 44 39 dielectric constant 2.52 1.78 2.11 2.02 1.92 1.79 2.3. potentiostatic corrosion test techniques fig. 2 demonstrates the collection of potentiostatic corrosion test equipment includes (computerized m-lap potentiostatic, water bath and three electrodes corrosion cell. the three corrosion cell electrodes are a working electrode (the sample material), a counter electrode (platonized titanium (pi-ti)), and the ag/agcl reference electrode. fig. 3 shows the electrochemical flow cell used in potentiostatic test. fig. 2. m-lap potentiostatic test collection fig. 3. electrochemical flow cell due to the low conductivity of crude oil, the potentiostatic corrosion test of the two types of pipelines material in crude oil is impossible. this test can increase the conductivity of crude oil through the use of the potter method for conducting the potentiostatic test ‎[21]. in the potter method, a small quantity of toluene (methylbenzene c6h5ch3) was added to the crude oil solution. h. h. jasim / iraqi journal of chemical and petroleum engineering 20,2 (2019) 41 50 22 the toluene is a solvent and selected for two reasons: first, the boiling point of the toluene must be higher than 60 o c and secondly, it must be causing the minimum interference. according to the potter method, a 30 ml toluene was added to 500 ml of crude oil and then added water to crude oil until the total water percentages reached to 5%. then mix the results with a mixer to make sure the mixture is very well mixed and put it in the glass cell. a ligament is a round glass cell is used to ensure that the test electrolyte medium is isolated from the air environment. the glass cell is inserted into a temperature controller bath containing water solution and maintained constant (within ± 0.1 °c) to control the test solution temperature. for conducting potentiostatic corrosion test, the specimen shall be a run under open circuit conditions for an exposure period of 60 minutes and the potential has been recorded at the end of the exposure period. the potential of ±250 mv is then applied to the measured open circuit potential of the working electrode at a scan rate of 0.5 mv/s. during the corrosion testing, a potentiostatic test is carried out for a total time of 1 hour and new crude oil and new specimen are used for each test. the computer-operated and controlled m-lap potentiostatic device was used to record data (current, voltage and test time) during the test. the m-lap science bank-electronics program version 5.1.exe is used. the output of the experiment test is a graph of the log current versus the potential plot. the curves result are analyzed using tafel linearization method and final output can produce the corrosion current icor.. using the corrosion current density , the rate of corrosion (cr) in mm/year was estimated by the following equation ‎[22]: (1) and (2) where, as: surface area of the specimen (cm 2 ). : density of metal (g/cm 3 ). icor : corrosion current obtained from tafel extrapolation method. the equivalent weight (ew ) is given by the following relation ‎[23]: ∑ (3) where, ai : atomic mass of the tested metal (g/mol). ni : valiancy. fi : mass fraction of alloying elements. 3model of co2 corrosion rate calculation the corrosion model in the ece program is based on the de waard-lotz corrosion model and two cathodic reactions are recognized ‎[24], ‎[25]: → (4) → (5) the metal anodic dissolution reaction balances the flow of electrons from these reactions, i.e. → (6) the basic rate of co2 corrosion (vcor.) is the combination of these two processes and given as: (7) where: vr and vm represent the maximum kinetic corrosion rate of proton corrosion, and a mass transfer rate of the dissolved co2. the equation for the proton reaction controlled part is ‎[26]: ( ) ( ) ( ) (8) moreover, for the part controlled by mass transfer: (9) where, t : temperature ( o c), u : the velocity of crude oil (m/s). d: pipe diameter in (m). : the ph of pure water saturated with co2. : the fugacity of the co2 (bar). phactual: the ph resulting from the presence of dissolved salts. the result from the eq.(7) is adjusted by the use of a number of multiplying factors for the presence of a protective scale ( ), h2s gas ( ) and crude oil ( ) on the base co2 corrosion rate as followers: (10) where: ( ) ( ) (11) (12) ( ) (13) and (14) h. h. jasim / iraqi journal of chemical and petroleum engineering 20,2 (2019) 41 50 24 where, : the angle of deviation from vertical. : water friction in crude oil. : partial pressure of gas in (bar). : partial pressure of gas in (bar). api: the american petroleum institute gravity. the partial pressure of dissolved gas was calculated using henry’s law as followers ‎[27]: (15) where, : henry’s constant 29.76 atm/ mol.lit. [co2]: the concentration of dissolved co2 gas in mol/lit. 3.2. fugacity of co2 dissolved gas ( ) the fugacity of co2 ( ) is similar to its effective partial pressure and its expressed in pa or atm., but corrected for non-ideality at high pressure and temperature. the basic equation for the correction of co2 fugacity used in ece software given as followers ‎[28]: ( ) ( ) ( ) (16) in ece v.5.1, the maximum total pressure p is limited to 250 bar and the equation is adjusted slightly for temperatures above 80°c by scale factors to provide a better fit in the fugacity curves. 4results and discussion the open circuit potentials or so called corrosion potential (ecor.) of api 5l x60 and api 5l x80 carbon steel obtained from open circuit potential are illustrated in table 6 at temperature 30 o c. the potentiostatic test begins at a temperature of 30 o c due to the small values of corrosion potential obtained at 25 o c and it is not appropriate to conduct the tests. as shown in table 6, the potential of the open circuit for different types of crude oil and steel has varied. increasing the potential for corrosion shows an improvement in the performance of corrosion protection since the electrons transferred from the samples have decreased. the crude oil from noor field has the lower potential, while crude oil from halfaya field has the largest value; other crude oils types have moderate values. fig. 4 shows polarization curves obtained from potentiosatic test under static and flow condition of crude oil at 1 m/s and temperature 30 o c of the materials api 5l x60 and x80 carbon steel in the noor crude oil. the slope of the polarization curves illustrated the velocity of reactions of the specimen’s surface with crude oil impurities. both pipeline materials showed large oscillations of applied potential with measured current, and as the applied potential increased, the curve fluctuations increased. it also notes that a small change in the potential (δe) leads to a significant change in the current (δi), which means that the velocity of the corrosion reaction is high. the polarization curve obtained from testing of x60 steel in this type of crude oil showed a significantly large change in curves, which is attributed to the high reaction speed and then the transfer of electrons is larger than x80 steel. as indicates in the polarization curve the x60 steel shows high corrosion speed compared to the x80 steel. table 6. open circuit potential (corrosion potential (ecor.) in mv) obtained from potentiostatic test at t = 30 o c static case steel types crude oil types halfaya faqa 1 abu gharab faqa 2 bazurkan noor api 5l x80 -87 -104 -119 -133 -151 -160 api 5l x60 --130 -151 -163 -176 -198 -210 flow case (1m/s) api 5l x80 -116 -136 -148 -161 -169 -180 api 5l x60 -160 -181 -201 -214 -227 -240 fig. 4. polarization curves under static and flow conditions in noor crude oil at 30 o c by varying the temperature and types of crude oil and conduct the potentiostatic corrosion analogue polarization curves of fig.4 can be obtained. to obtain the corrosion current using the tafel method, the polarization curves of fig. 4 were analyzed. this was done using the software version 5.1.exe of the m-lab science program to obtain the corrosion current. the equivalent weight of carbon steel x60 and x80 is calculated using eq.(3) and the value of the corrosion rate is calculated using eq.(1) at a constant temperature. the final results of the conclusions are illustrated in fig. 5 a to f. fig. 5 a to f show the rate of corrosion vs. temperature obtained from potentiostatic test the pipeline materials in the six types of crude oils. comparing the rates of corrosion results between these fields, it was found that the crude oil from noor field shows the highest rate of corrosion, while crude oil from halfaya field shows the least values; other crude oils show moderate values. h. h. jasim / iraqi journal of chemical and petroleum engineering 20,2 (2019) 41 50 24 the rates of corrosion differ may be because the crude oil from noor field has the highest water and impurities as given in table 4 and table 5. both pipeline materials have a steady value of increases in the corrosion rate during the increases in temperature. the results of testing in the flow crude oil indicate that the corrosion current is significantly increased due to the effect of the crude oil velocity factor, which contributes to increasing the diffusion of different ions in steel surfaces during the test. table 7 shows a comparison of the rate of corrosion between the two carbon steel materials api 5l x60 and api 5l x80 tested in the six types of crude oils at 30 o c. as shown in table 7, when both materials tested in crude oil from noor field, the carbon steel api 5l x60 has a corrosion rate of 0.190 mm/y and 0.295 mm/y in static and flow cases respectively, while the carbon steel api 5l x80 has a corrosion rate of 0.156 mm/y and 0.263 mm/y in static and flow cases respectively. the results of the test in crude oil from halfaya field show that the carbon steel api 5l x60 has a corrosion rate of 0.081 mm/y and 0.092 mm/y in static and flow cases respectively, while api 5l x80 carbon steel has a corrosion rate of 0.042 mm/y and 0.053 mm/y in static and flow cases respectively. other types of crude oils have moderates corrosion rate values. the crude oil flow is effects on the rate of corrosion by different methods. compared to the static case, the corrosion ion and impurities transport in crude oil increases with crude oil flow. this accelerates the corrosion reaction within pipelines. therefore, the rate of corrosion increased in case of flow compared to the static case. the flow effect on the inhibition element, in particular asphalt, which is collected at the bottom of the pipeline surface and thus weakens the inhibition element. on the other hand, higher crude oil flow leads to higher turbulence, which increases the wall shear stress and further increases the pipeline corrosion rate. the scouring effect of high-speed oil flows can quickly destroy films of corrosion products or prevent the formation of films due to corrosion, which reduces the effect of corrosion inhibitors. in static cases, the rate of corrosion is lower because the oil film protects the surface of the specimen from corrosion by reduces the contact of impurities and ions with the specimen surfaces. the conductivity of crude oils is one of the important factors affecting the corrosion rate values during the potentiostatic test. it has depended on various factors including; water percent temperature, metal concentration, ion concentration, and presence of organic matter, dissolved gases and ph values. the current is relatively high at the start of the test and then started to decrease to lower steady values, this is due to ions and compounds that support corrosion reactions is removed and consumption. as the temperature of crude oil increases, the ions contained in crude oil contribute to increase the flow of electrons and move more freely through crude oil to the reference electrode and increase the oxidation and reduction processes, leading to faster rates of corrosion. noor crude oil has the highest amount of metal compositions and water percent compared to other crude oils as given in table 4. chloride salts such as nacl, cacl2, mgcl2, it is found in crude oil with different concentrations. as the temperature or flow of crude oil increases, the mixture of this chloride salts with water in crude oil and hydrolysis increases. the hydrolysis of chloride salts in water leads to the initiation of a strong hcl acid, which increases the acidity of crude oil (ph value) and enhances the rate of corrosion. chloride salt hydrolysis can be administered by the following reactions [25]: nacl + h2o naoh + hcl (17) mgcl2 + 2 h2o mg(oh)2 + 2hcl (18) cacl2 + 2 h2o ca(oh)2 + 2hcl (19) the chloride salt nacl and kinematics viscosity for noor oilfields are 44 ppm and 35.5 cst, respectively, according to table 4. since the viscosity is low; this made the flow of crude oil is easily compared to other types. it also increases the contact of impurities contained in crude oil with the internal surface of pipelines leading to a faster rate of corrosion. table 7. corrosion rate values in (mm/year) obtained from test at t = 30 o c static case steel type crude oil types halfaya faqa 1 abu gharab faqa 2 bazurkan noor api 5l x80 0.042 0.059 0.094 0.116 0.132 0.156 api 5l x60 0.053 0.069 0.121 0.134 0.15 0.190 flow case (1m/s) api 5l x80 0.081 0.130 0.152 0.163 0.204 0.263 api 5l x60 0.092 0.110 0.164 0.186 0.243 0.295 to illustrate the effect of concentration of co2 and h2s dissolved gases in corrosion rate, engineering corrosion software (ece) was used to calculate the corrosion rate at various temperatures for both types of pipeline material. the rate of corrosion for each type of steel tested in each type of crude oils is estimated at a constant temperature for a pipeline length of 100 m. for executing the ece software program, the total pressure was taken as 50 bar and the pressure of dissolved co2 gas was calculated according to the concentration of co2 dissolved gas in each type of crude oils using eq.(15). then, the corrosion rate in the range of temperatures from 20 o c to 65 o c was obtained from ece software program and drawn as a function of temperatures in fig. 6. h. h. jasim / iraqi journal of chemical and petroleum engineering 20,2 (2019) 41 50 24 fig. 5. corrosion rate vs. temperature for fields: ahalfaya b-faqa 1 cabu gharab d-faqa 2 ebazurkan fnoor h. h. jasim / iraqi journal of chemical and petroleum engineering 20,2 (2019) 41 50 24 as indicated in fig. 6, due to the low concentration of dissolved gasses co2 and h2s, which listed in table 4, the corrosion rate is very small. most corrosion rate occurs due to the effect of water and other impurities of crude oil in addition to the operating condition include temperature and pressure in pipes. fig. 6. effect of co2 on corrosion rate at various temperatures for fields: abazurkan bnoor cfaqa 2 dabu gharab efaqa 1 fhalfaya the co2 gas mixture with water forms weak carbonic acid (h2co3) for both cases of static and flow, but the flow of crude oil has improved reactions, the transfer of ions and carried out more corrodes species to the exposure area of the steel specimen, this caused higher rates of corrosion. in general, both co2 and h2s gasses in water were analyzed to form cations and anion compounds, and these increased reactions occurred in the anode and cathode parts of the potentiostatic test. the following equations are illustrated the analyzed dissolved gasses co2 and h2s in water: co2 (g) + h2o (l) h + (aq) + hco3 (aq) (20) h2s (g) + h2o (l) (aq) + (aq) (21) fig. 7. surfaces of specimens after test in the six different types of crude oils h. h. jasim / iraqi journal of chemical and petroleum engineering 20,2 (2019) 41 50 24 fig. 7 illustrates the microscopic surface of specimens after conducted the potentiostatic test in the six types of crude oil at ambient temperature. to remove crude oil deposits on the specimen's surface, kerosene was used to clean the specimens. there are two types of localized corrosion, pitting and general corrosion. the images of the surface of the specimens in fig. 7 after the potentiostatic test in static and flow conditions show that a rough and porous surface was produced, i.e. numerous cavities with small pits covering the surfaces. in the case of a flow condition, the number of cavities and pits are visually higher than that in a static condition due to the effect of flow. it is clear from the surface microstructures of fig. 7, x60 shows more surface damage under flow conditions than in static conditions, and the pits were uniformly distributed over the surface, which was surrounded by a small area of corrosion. it also indicates the formation of oxides layer spread on the steel surface at various points obtained following a potentiostatic test in crude oil solutions. a comparison of the specimen’s surfaces between static and flow conditions, it shows that the actual corrosion pits have more complex geometries in flow conditions with different pit depths and length than in static cases. 5conclusions based on the results of this study, the following concluded are obtained: 1the result of the potentiostatic polarization tests showed that the polarization curves have a significant large oscillation associated with the initiation of unstable pits and high electrical resistance of crude oils. 2the corrosion rate of co2 and h2s dissolved gases obtained from ece software program is minimal due to the small concentration of co2 and h2s dissolved gases in the tested crude oil. 3the x80 carbon steel has lower corrosion values, while the x60 carbon steel has largest values. 4noor crude oil has the highest corrosion rate value, while halfaya crude oil has the lowest value; another crude oil has moderate values. 5the corrosion rate in case of crude oil flow is larger than that obtained at static. 6the surface of the samples tested showed pits and cavities covered the surfaces and both materials showed more damage in the surfaces under flow conditions than in a static case. acknowledgments the author would like to thank the staff engineer at maysan oil company and nahr umer laboratory for various helps and supports in the analysis of crude oils. references [1] j. enani, “corrosion control in oil and gas pipelines”, international journal of scientific & engineering research, 2016, vol.7, issue 4, pp.1161-1164. [2] s. nesic, “key issues related to modeling of internal corrosion of oil and gas pipelines a review”, corrosion science, 2007, vol.49, pp.4308–4338. [3] a. s. yaro and k. h. rashid , “modeling and optimization of carbon steel corrosion in co2 containing oilfield produced water in presence of hac”, iraqi journal of chemical and petroleum engineering, 2015, vol.16, no.2, pp.18. [4] l. m. smith and de waard k., “corrosion prediction and materials selection for oil and gas producing environments”, corrosion 2005, paper 05648: nace international. [5] l. esteves, m. cardosoa and v. linsa, “corrosion behavior of duplex and lean duplex stainless steels in pulp mill”, materials research, 2018, vol.21, no.1, pp.1-9. [6] q. sulaiman , a. al–taie, d. m. hassan, “evaluation of sodium chloride and acidity effect on corrosion of buried carbon steel pipeline in iraqi soil”, 2014, iraqi journal of chemical and petroleum engineering, vol.15 no.1, pp.1-8. [7] a. k. vuppu and w. p. jepson, “the effect of temperature in sweet corrosion of horizontal multiphase carbon steel pipelines”, paper no. spe28809-ms, spe asia pacific oil and gas conference, 7-10 november, melbourne, australia, 1994. [8] l. xu and x. wang, “the research of oil and gas pipeline corrosion and protection technology”, advances in petroleum exploration and development, 2014, vol.7, pp.102-105. [9] prakash, s. surya, et al. "internal corrosion management of crude pipelines." 2014 10th international pipeline conference. american society of mechanical engineers, 2014. [10] t. a. saleh, s. husain sahi and l. s. mohamed. “corrosion of electrical submersible pumps (esp) in south rumaila oil field”, iraqi journal of chemical and petroleum engineering, 2015, vol.16, no.1, pp.6369. [11] z. m. wang and j. zhang, “corrosion of multiphase flow pipelines: the impact of crude oil”, corros. rev., 2016, vol.34, no.2, pp.17-40. [12] h. j. muhammed, “effects of soil properties on corrosion of soil pipeline at north of iraq”, m.sc. thesis, mechanical engineering department, near east university, erbil, 2016. [13] h. s. mobbassar and a. m. abdullah, “corrosion of general oil-field grade steel in co2 environment update the light of current understanding”, int. j. electchem. sci., 2017, vol.12, [14] n. i. mursalov, “characteristic and mechanism of hydrogen sulfide corrosion of steel”, the journal of processes of petrochemistry and oil refining (ppor), 2017, vol.18, pp.215-228. https://www.ijser.org/researchpaper/corrosion-control-in-oil-and-gas-pipelines.pdf https://www.ijser.org/researchpaper/corrosion-control-in-oil-and-gas-pipelines.pdf https://www.ijser.org/researchpaper/corrosion-control-in-oil-and-gas-pipelines.pdf http://www.icmt.ohio.edu/documents/publications/8020.pdf http://www.icmt.ohio.edu/documents/publications/8020.pdf http://www.icmt.ohio.edu/documents/publications/8020.pdf http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/249 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/249 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/249 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/249 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/249 http://www.intetech.com/images/downloads/paper71.pdf http://www.intetech.com/images/downloads/paper71.pdf http://www.intetech.com/images/downloads/paper71.pdf http://www.intetech.com/images/downloads/paper71.pdf http://www.scielo.br/pdf/mr/v21n1/1516-1439-mr-1980-5373-mr-2017-0148.pdf http://www.scielo.br/pdf/mr/v21n1/1516-1439-mr-1980-5373-mr-2017-0148.pdf http://www.scielo.br/pdf/mr/v21n1/1516-1439-mr-1980-5373-mr-2017-0148.pdf http://www.scielo.br/pdf/mr/v21n1/1516-1439-mr-1980-5373-mr-2017-0148.pdf http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/263 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/263 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/263 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/263 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/263 http://www.icmt.ohio.edu/documents/publications/8058.pdf http://www.icmt.ohio.edu/documents/publications/8058.pdf http://www.icmt.ohio.edu/documents/publications/8058.pdf http://www.icmt.ohio.edu/documents/publications/8058.pdf http://www.icmt.ohio.edu/documents/publications/8058.pdf http://www.cscanada.net/index.php/aped/article/view/5091/pdf_11 http://www.cscanada.net/index.php/aped/article/view/5091/pdf_11 http://www.cscanada.net/index.php/aped/article/view/5091/pdf_11 http://www.cscanada.net/index.php/aped/article/view/5091/pdf_11 http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=2022659 http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=2022659 http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=2022659 http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=2022659 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/245 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/245 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/245 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/245 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/245 https://doi.org/10.1515/corrrev-2015-0053 https://doi.org/10.1515/corrrev-2015-0053 https://doi.org/10.1515/corrrev-2015-0053 http://docs.neu.edu.tr/library/6362314494.pdf http://docs.neu.edu.tr/library/6362314494.pdf http://docs.neu.edu.tr/library/6362314494.pdf http://docs.neu.edu.tr/library/6362314494.pdf http://www.electrochemsci.org/papers/vol12/120504277.pdf http://www.electrochemsci.org/papers/vol12/120504277.pdf http://www.electrochemsci.org/papers/vol12/120504277.pdf http://www.electrochemsci.org/papers/vol12/120504277.pdf http://jppor-az.com/jpdf/murselov-3(2017).pdf http://jppor-az.com/jpdf/murselov-3(2017).pdf http://jppor-az.com/jpdf/murselov-3(2017).pdf http://jppor-az.com/jpdf/murselov-3(2017).pdf h. h. jasim / iraqi journal of chemical and petroleum engineering 20,2 (2019) 41 50 45 [15] m. l. cedeño, e. l. vera and y. t. pineda, “effect of contents oil temperature and flow rate in the electrochemical corrosion of the aisisae1020 steel”, iop conf. series786, journal of physics, 2017, pp.1-8. [16] f. kolawole, s. kolawole, j. agunsoye, j. adebisi, s. bello and s. hassan, “mitigation of corrosion problems in api 5l steel pipeline-a review”, j. mater. environ. sci., 2018, vol.9, n0. 8, pp. 2397-2410. [17] api 5l x80 carbon steel specification data sheet, report of the henan bebon international co. ltd., 2015, chaini. [18] api 5l x60 carbon steel specification data sheet, report of the henan bebon international co. ltd., 2016, chaini. [19] astm g1-03, standard practice for preparing, cleaning, and evaluating corrosion test specimens, report of astm 2011. [20] astm g59-97, standard test method for conducting potentiodynamic polarization resistance measurements, report of astm, usa, 2014. [21] a. c. potter, “crude oil conductivity presentation”, report of nalco energy service, 2007. [22] g-102, standard practice for calculation of corrosion rates and related information from electrochemical measurements, report of astm, usa, 1999. [23] o. n. sylvester, o. n. celestine, o. g. reuben and c. e. okechukwu, “review of corrosion kinetics and thermodynamics of co2 and h2s corrosion effects and associated prediction/evaluation on oil and gas pipeline system”, int. j. of sci. & tech. res., 2012,vol.1, pp.1-17. [24] c. de waard, and l. m. smith and b. d. criag, “the influence of crude oil on well tubing corrosion rate”, nace corrosion conference, paper no.03629, 2003. [25] c. de waard, u. lotz and a. dugstad, “influence of liquid velocity on co2 corrosion: a semi-empirical model”, nace corrosion 95, paper no. 128. [26] m. h. abbas, “modeling co2 corrosion of pipeline steels”, ph.d., school of marine science and technology, newcastle university, usa. 2016. [27] p. s. brown, “optimizing the long-term capacity expansion and protection of iraqi oil infrastructure”, m.sc. thesis, naval postgraduate school, monterey, california, usa, 2005. [28] m. r. gray, p. e. eaton and t. le, “kinetics of hydrolysis of chloride salts in model crude oil”, petroleum science and technology, 2008, vol.26, no.16, pp.1924-1933. تقييم تاثير السرعة والحرارة عمى معدل التاكل في انابيب النفط الخام بوجود الغازات المذابة co2/h2s الخالصة وسرعة النفط الخام عمى معدل التأكل في co2/h2s المذابة في هذا البحث، تم دراسة تأثير الغازات االنابيب المستخدمة في نقل النفط الخام من ستة حقول مختمفة في محافظة ميسان جنوب العراق وهي )نور، (. اجريت االختبارات العممية باستخدام طريقة الجهد الساكن 2وفكه 1بزركان، الحمفاية، ابو غريب، وحقول فكه الكتروني . استخدم البرنامج api 5l x60و api 5l x60الصمب الكربوني وهما عمى نوعين من انابيب ece وتقيم تأثير كل من الضغط الجزئي لغاز حساب معدل التأكللco2 تركيب النفط الخام، سرعة النفط ، نوع الخام ونسب العناصر المكونة لمصمب عمى معدل التأكل. بينت النتائج العممية ان الصمب الكربوني من api 5l x80 اظهر مقاومة اعمى لمتأكل مقارنة بالصمب الكربونيapi 5l x60 كما ان معدل التأكل في . حالة الجريان يكون اكبر منه في حالة السكون. اظهر النفط الخام من حقل نور اعمى قيمة لمعدل التأكل، بينما الحقول االخرى امتمك قيم متوسطة من معدالت النفط الخام من حقل الحمفاية امتمك اقل قيمة، النفط الخام من التأكل. https://iopscience.iop.org/article/10.1088/1742-6596/786/1/012039/pdf https://iopscience.iop.org/article/10.1088/1742-6596/786/1/012039/pdf https://iopscience.iop.org/article/10.1088/1742-6596/786/1/012039/pdf https://iopscience.iop.org/article/10.1088/1742-6596/786/1/012039/pdf https://iopscience.iop.org/article/10.1088/1742-6596/786/1/012039/pdf https://www.jmaterenvironsci.com/journal/vol9-8.html https://www.jmaterenvironsci.com/journal/vol9-8.html https://www.jmaterenvironsci.com/journal/vol9-8.html https://www.jmaterenvironsci.com/journal/vol9-8.html https://www.jmaterenvironsci.com/journal/vol9-8.html http://www.steel-plate-sheet.com/steel-plate/api/x80.html http://www.steel-plate-sheet.com/steel-plate/api/x80.html http://www.steel-plate-sheet.com/steel-plate/api/x80.html %5b1%5d%09http:/www.steel-plate-sheet.com/steel-plate/api/api-5l-x60.html %5b1%5d%09http:/www.steel-plate-sheet.com/steel-plate/api/api-5l-x60.html %5b1%5d%09http:/www.steel-plate-sheet.com/steel-plate/api/api-5l-x60.html https://pdfs.semanticscholar.org/9bd4/ae202c3135479d889d43707d245486dc872d.pdf https://pdfs.semanticscholar.org/9bd4/ae202c3135479d889d43707d245486dc872d.pdf https://pdfs.semanticscholar.org/9bd4/ae202c3135479d889d43707d245486dc872d.pdf https://pdfs.semanticscholar.org/9bd4/ae202c3135479d889d43707d245486dc872d.pdf https://pdfs.semanticscholar.org/9bd4/ae202c3135479d889d43707d245486dc872d.pdf https://pdfs.semanticscholar.org/9bd4/ae202c3135479d889d43707d245486dc872d.pdf http://www.intetech.com/images/downloads/paper65.pdf http://www.intetech.com/images/downloads/paper65.pdf http://www.intetech.com/images/downloads/paper65.pdf http://www.intetech.com/images/downloads/paper65.pdf https://www.osti.gov/biblio/106125-influence-liquid-flow-velocity-co-sub-corrosion-semi-empirical-model https://www.osti.gov/biblio/106125-influence-liquid-flow-velocity-co-sub-corrosion-semi-empirical-model https://www.osti.gov/biblio/106125-influence-liquid-flow-velocity-co-sub-corrosion-semi-empirical-model https://www.osti.gov/biblio/106125-influence-liquid-flow-velocity-co-sub-corrosion-semi-empirical-model https://theses.ncl.ac.uk/dspace/bitstream/10443/3530/1/abbas%2c%20m.h%202016.pdf https://theses.ncl.ac.uk/dspace/bitstream/10443/3530/1/abbas%2c%20m.h%202016.pdf https://theses.ncl.ac.uk/dspace/bitstream/10443/3530/1/abbas%2c%20m.h%202016.pdf https://apps.dtic.mil/dtic/tr/fulltext/u2/a439532.pdf https://apps.dtic.mil/dtic/tr/fulltext/u2/a439532.pdf https://apps.dtic.mil/dtic/tr/fulltext/u2/a439532.pdf https://apps.dtic.mil/dtic/tr/fulltext/u2/a439532.pdf https://www.tandfonline.com/doi/abs/10.1080/10916460701402412 https://www.tandfonline.com/doi/abs/10.1080/10916460701402412 https://www.tandfonline.com/doi/abs/10.1080/10916460701402412 https://www.tandfonline.com/doi/abs/10.1080/10916460701402412 iraqi journal of chemical and petroleum engineering vol.17 no.3 (september 2016) 7581 issn: 1997-4884 applied spatial data analysis technique on petrophysical properties of ma unit of mishrif formation / noor field hussain ali baker, sameer noori al-jawad * and aseel ali abdulla petroleum engineering department, college of engineering, university of baghdad * development directorate, reservoir and field, ministry of oil abstract noor oil field is one of smallest fields in missan province. twelve well penetrates the mishrif formation in noor field and eight of them were selected for this study. mishrif formation is one of the most important reservoirs in noor field and it consists of one anticline dome and bounded by the khasib formation at the top and the rumaila formation at the bottom. the reservoir was divided into eight units separated by isolated units according to partition taken by a rounding fields. in this paper histograms frequency distribution of the porosity, permeability, and water saturation were plotted for ma unit of mishrif formation in noor field, and then transformed to the normal distribution by applying the box-cox transformation algorithm. the spatial correlation of the transformed parameters were estimated and modeled in appropriate equation, and then the spatial distribution of the reservoir parameters were specified through geostatistical methods. keywords: statistical analysis, variogram, mishrif formation, noor field. introduction most geostatistical methods assume that the parameters under study were normally distributed such that the deviations from this assumption lead to skewness in estimation [1], to avoid this problem, histograms of the porosity, permeability, and water saturation frequency distribution were plotted for reservoir ma unit in mishrif formation, and then transformed to the normal distribution by applying the box-cox transformation. the spatial correlation of the transformed parameters were estimated and modeled in appropriate equation, and then the spatial distribution of the reservoir parameters were specified through geostatistical methods. experimental decriptive statistics geostatistical simulation require the data to be approximately normally distributed (close to a bell-shaped curve) and stationary (mean and variance do not vary significantly in space), significant deviations from normality and stationary can cause problems, so it is always best to begin by looking at a histogram to check for normality and a posting of the data values in space to check for significant trends [2]. dealing with samples that university of baghdad college of engineering iraqi journal of chemical and petroleum engineering applied spatial data analysis technique on petrophysical properties of ma unit of mishrif formation / noor field www.iasj.netavailable online at: 6) 201 september( 3no. 7ijcpe vol.1 67 are symmetric and that show narrow spread is always easier than dealing with highly skewed samples with a large spread [3]. frequency distribution histogram and its summary statistics were made for characterizing porosity, water saturation, and permeability at each zone in mishrif formation to investigate the symmetry and the spread of the data [4]. the histogram in figure 1-a characterizes porosity, the total number of points are 320, limited between 0.0001 and 0.21. the average porosity is greater than that of the most frequency, indicating that the distribution is skewed positively to the right. the coefficient of variation (cv) is close to one, indicating that the variation of porosity in ma unit is approximately low. as shown in figure 1-b, which represents the histogram of water saturation, the value of water saturation ranging from 0.122 to 1, the average value equal to 0.71, i.e, less than the mode value which indicating negative skew (to the left), and the coefficient of variation is close to zero indicating the variation of water saturation in ma unit is low. although the permeability value of ma unit range from 0.002 md to 51.6647md, as shown in figure 1-c, the majority of the values are at the lower end of the range where the permeability distribution is positively skewed (to the right). the coefficient of variation is greater than one, indicating that the variation in permeability for ma unit is approximately high and should be treated with care when estimating values at un sampled locations. fig .1: petro physical properties histogram for ma unit, (a) phie, (b) sw, (c) k data tranformation when data is skewed or has extreme high or low values; estimated variograms often exhibit unorganized behaviors [5]. box and cox [6] developed a procedure to identify an appropriate exponent (lambda) to use for skewness removal and transforming data into a normal shape. the final algorithm is: y(λ)=(yλ-1)/λ, λ≠0 …(1) y(λ) =log (y), λ = 0 …(2) lambda (λ) expresses the degree of skewness and y(λ) is the transformed value of the original observation (y). the box-cox transformation coefficient using any statistical package or by hand to estimate the effects of a selected range of λ automatically [7]. the λ can take on an almost infinite number of values. one can theoretically calibrate a transformation to be maximally effective in moving a variable toward http://www.iasj.net/ hussain ali baker, sameer noori al-jawad and aseel ali abdulla 66 )6201september ( 3no. 17ijcpe vol. www.iasj.netonline at: available normality, regardless of whether it is negatively or positively skewed. this family of transformations incorporates many traditional transformations [7]: λ = 1.00: no transformation needed; produces results identical to original data. λ = 0.50: square root transformation. λ = 0.33: cube root transformation. λ = 0.25: fourth root transformation. λ = 0.00: natural log transformation. λ=-0.50: reciprocal square root transformation. λ=-1.00: reciprocal (inverse) transformation. data transformations are commonlyused tools that can serve many functions in quantitative analysis of data, including improving normality of a distribution and equalizing variance to meet assumptions thus constituting important aspects of data cleaning and preparing for statistical analyses[8]. the lambda (λ) has been estimated depending on statistical packages in petrel software, where cox-box transformation technique was applied on porosity, water saturation and permeability data for checking what if the data need to transform or not and making the necessary transformation if need [4]. the square root transformation was selected to improve the distribution behave of porosity data in ma unit since the estimated lambda equal to 0.5, the transformation result are shown in figure 2. the estimated λ was equaled to 1, when cox-box transformation was applied on water saturation data in ma unit, as a result there is no need to make transformation since it will produce results identical to original data as shown in figure 3. natural log transformation was selected to transform the permeability data in ma unit where the estimated λ was equaled to 0.00, as shown in figure 4. fig. 2: porosity transformation for unit ma fig. 3: water saturation transformation for unit ma fig. 4: permeability transformation for unit ma variogram analysis variogram is a measure of correlation between rock properties at two locations [9]. the variogram is mathematically defined as [10]: http://www.iasj.net/ applied spatial data analysis technique on petrophysical properties of ma unit of mishrif formation / noor field www.iasj.netavailable online at: 6) 201 september( 3no. 7ijcpe vol.1 67 ( )=1/2var[( + )-( ) …(3) the principle of the variogram is that two closely located samples have less dissimilarity than two samples far away from each other [11]. the variogram is a critical input to geostatistical studies, it is a tool to investigate and quantify the spatial variability of the phenomenon under study, and the underlying techniques behind most geostatistical estimation or simulation algorithms require an analytical variogram model which they will honor [12]. in the construction of 3d high-resolution numerical models of reservoir properties, the variogram reflects some of our understanding of the geometry and continuity of petrophysical properties, and can have a very important impact on predicted flow behavior and consequent reservoir management decisions[12]. for the variogram analysis of mishrif formation, porosity, permeability and water saturation, were utilized to calculate corresponding experimental variograms [4]. the experimental variogram was computed and plotted for petrophysical properties after defining the major and minor areal directions of the variogram depending on 2d variogram map [13] which is a plot of experimental variogram values in a coordinate system with the center of the map corresponding to the variogram at lag equal zero. figure 5 represents the 2d variogram map calculated from water saturation where the elliptic shape indicates geometric anisotropy occurs in the areal direction. the location map, figure 6-a, represent the wells location and the major direction of the areal variogram where the orientation of the major direction equal to 183˚. the orientation of the minor direction is perpendicular to the major direction and equal to 93˚ in our study as shown in figure 6-b. the search radius equal to 6000 m which represent the maximum distance between two samples of dataand the number of lags were chosen to be 20 lags with lag distance equal to 362.3 m. fig. 5: 2d variogram map calculated from water saturation fig. 6: location map; a) major direction and b) minor direction porosity variography the experimental variogram of normalized porosity indicates a behavior that can be described as a combination of exponential variogram where the variogram change very gradually at the origin, and dampened hole-effect (cyclic) variogram [12] which observed after reaching a sill value where the experimental variogram alternated from positive correlations to negative correlations at a length scale directly linked to the geologic cycles as shown in figure 7, http://www.iasj.net/ hussain ali baker, sameer noori al-jawad and aseel ali abdulla 67 )6201september ( 3no. 17ijcpe vol. www.iasj.netonline at: available which represents the experimental variogram for normalized porosity of ma unit in three directions. fig. 7: experimental variogram of normalized porosity, ma unit the final model for the horizontal and vertical variability of porosity variograms of ma unit in mishrif formation is summarized as given in table (1). table 1: variogram analysis of porosity for ma unit in mishrif formation sill nugget major range (m) minor range (m) vertical range (m) 0.994 0.00 2126.6 1997.6 14 water saturation variography since the experimental variogram of normalized water saturation rises rapidly for a given range, the spherical model was chosen to be a good option to model the variogram, figure 8 represent the experimental variogram for normalized water saturation of ma unit in three directions. the final model for the horizontal and vertical variability of water saturation variograms of ma unit in mishrif formation is summarized as given in table 2. fig. 8: experimental variogram of normalized water saturation, ma unit table 2: variogram analysis of water saturation for ma unit in mishrif formation sill nugget major range (m) minor range (m) vertical range (m) 1.12 0.00 1243.6 1171.4 23 permeability variography the experimental variogram of normalized permeability is similar to the pattern found for normalized porosity as a resultthe exponential model was chosen to be a good option to model the variogram, figure 9 represent the experimental variogram for normalized permeability of ma unit in three directions. the final model for the horizontal and vertical variability of permeability variograms of mishrif formation is summarizedas given in table 3. table 3: variogram analysis of permeability in mishrif formation sill nugget major range (m) minor range (m) vertical range (m) 1.00 0.0 3502.2 3305.3 22 http://www.iasj.net/ applied spatial data analysis technique on petrophysical properties of ma unit of mishrif formation / noor field www.iasj.netavailable online at: 6) 201 september( 3no. 7ijcpe vol.1 78 fig. 9: experimental variogram of normalized permeability, ma unit modeling of petrophysical properties for porosity, water saturation, and permeability, the sequential gaussian simulation technique was applied to interpolate data and to obtain multiple realizations [4] where the distribution of petrophysical properties were characterized without the consideration of the rock type parameters as a possible guide where thirty (30) realizations were generated for describing the possible distributions of porosity, water saturation, and permeability, then the typical output image was obtained according to the accuracy in frequency distribution and summary statistics. through using the porosity, water saturation, and permeability variogram models summarized as given in tables (1, 2, 3) respectively and sequential gaussian algorithm, the distribution of porosity, water saturation, and permeability were made as shown in figure 10, figure 11 and figure 12 respectively. fig. 10: porosity distribution of ma unit fig. 11: water saturation of ma unit fig. 12: permeability distribution of ma unit conclusions 1. the descriptive statistics results indicate that ma unit has a symmetrical distribution of porosity while the distribution of water saturation was negatively skewed and the distribution of permeability was positively skewed. 2. cox-box transformation technique was removed the skewed behavior and improved the distribution of the petrophysical properties of ma unit http://www.iasj.net/ hussain ali baker, sameer noori al-jawad and aseel ali abdulla 78 )6201september ( 3no. 17ijcpe vol. www.iasj.netonline at: available of mishrif formation in noor field toward the normal distribution. 3. exponential model was applied to represent the variogram model of porosityand permeability, while spherical model was the best fitted for modeling the experimental variogramof water saturation in mishrif formation. 4. the distribution of petrophysical properties in space has been done by using the sequential gaussian simulation technique to interpolate data without the consideration of the rock type parameters as a possible guide. nomenclature eda=exploratory data analysis. cv = the coefficient of variation. λ=expresses the degree of skewness. ( )=theoretical variogram. ( + ), ( ) =random variables. = position vector. = distance between two points (lag). sill= the variance when the variogram levels out. nugget= the variance when the distance between two measured samples is very close to zero. references 1. rendu, j.m., 1981 “an introduction to geostatistical method of mineral evaluation”, the south africa institute of mining and metallurgy. 2. yarus, j.m. and chambers, r.l, 2006 “practical geostatistics-an armchair overview for petroleum reservoir engineers”, jpt. 3. geoff bohling, 2007 “introduction to geostatistics in hydro geophysics: theory, methods, and modeling”, boise state university, boise, idaho . 4. aseel ali, 2014 “geostatistical study of mishrif reservoir in noor oil field”, athesis submitted to the college of engineering, university of baghdad. in partial fulfillment of the requirement for the degree of master of science in petroleum engineering. 5. gringarten & clayton v. deutsch, 2001 “variogram interpretation and modeling”, mathematical geology, vol.33, no.4. 6. box, g. e. p., & cox, d. r., 1964 “an analysis of transformations”. journal of the royal statistical society, b.26 (211-234.) 7. jason w. osborne, 2010 “improving your data transformations: applying the boxcox transformation”, practical assessment, research & evaluation, vol 15, no.12. 8. hartmann, d. j. and coalson, e. b. , 1990 “evaluation of the morrow sandstone in sorrento field, cheyenne county, colorado”, the rocky mountain association of geologists, denver, colorado, pp. 91 – 100. 9. j.k. caers, 2000 “geostatistical quantification of geological information for a fluvial-type north sea reservoir”, spe reservoir evaluation & engineering, spe 66310. 10. bachmaier, m., backes, m., 2008 “variogram or semivariogram? understanding the variances in a variogram”, precision agric, volume 9, issue 3, 173–175. 11. niklas gunnarsson, , 2011 “3d modeling in petrel of geological co2 storage site”, department of earth sciences, uppsala university, villavägen 16, se-752 36 uppsala, issn 1401-5765. 12. gringarten & c. v. deutsch, 2003 “methodology for improved variogram interpretation and modeling for petroleum reservoir characterization.” 13. goovaerts, p, 1998 “geostatistics for natural resources evaluation”, oxford university press, new york. http://www.iasj.net/ available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.19 no.4 (december 2018) 47 – 53 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: nazaneen said amin, email: naz7eng@yahoo.com, ayad a.alhaleem, email: ayadah62@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. analysis of stuck pipe incidents in khabaz field nazaneen said amin a and ayad a.alhaleem b a drilling department /north oil company b petroleum engineering department/ college of engineering/ university of baghdad abstract there are many events which causes nonproductive time (npt) in the drilling industry. the mostly effective in this npt is pipe sticking event. a considerable amount of time and resources can be spent in efforts to free a stuck pipe. in addition, unsuccessful fishing operations results in costly alternatives including side-tracking. the drilling in khabaz oil field poses many operational challenges among of them stuck pipe , lost circulation, flow of salt water during drilling, and hole caving. stuck pipe can be considered the quite difficult problem in khabaz oil field due to associated incidents which lead to npt activities. well khabaz -34 was selected to study the problem of stuck pipe in this field. an analysis of stuck pipe events was made by using the graphical analysis software easy view. the results were then discussed to identify the causes of stuck pipe. finally, recommendation to select proper type /drilling fluid rheology properties, optimize casing seat design to reduce probability of stuck pipe. keywords: khabaz oil field, easy view received on 02/02/8102, accepted on 24/06/8102, published on 01/08/8102 https://doi.org/10.31699/ijcpe.2018.4.6 1introduction one of earliest papers on stuck pipe was discussed causes, prevention, and recovery of stuck pipe, major causes are described as key seating, improper mud control, cuttings, sand, caving, and balling up. many of the causes and practices are the same ones the industry deals with today ‎[1]. british petroleum company achieved 70% reduction in company-wide stuck pipe costs mainly by recognizing the importance of drilling contractor and service company, promoting a rig team approach including training on rig team stuck pipe problem solving, and raising awareness through coordinate worldwide communication program‎[2]. 54% of stuck pipe events analyzed (58 of 108) occurred while tripping and back reaming in schlumberger's data set‎[3]an increasing in the risk of stuck pipe was observed due to a recent increase in drilling activities, drilling in depleted and higher-risk reservoirs ‎[4].many researchers proposing the use of a statistical method for predicting stuck pipe ‎[5], ‎[6]. 2analysis of stuck pipe incidents in khabaz oil field khabaz oil field is located in the north east of iraq at approximately 20 km north west of kirkuk city. it lies between jambur and bai hassan structures and south west of the baba dome. the field was discovered in 1955, the first well kz-1 drilled on april 1976 and the last well kz-42 drilled in 2016. the khabaz structure (tertiary & cretaceous reservoir) consists of an elongated asymmetrical anticline, with15 km length and 5 km width, with a nw-sw axis and faulted mainly on its west flank by reverse. many historical wells have been drilled in the khabaz oil field show the general risks faced while drilling include the presence of multiple marly and siltstone formation causes tight hole section, stuck pipe events/ massive salt layers in the saliferous formation which affect wellbore stability ‎[7],lost circulation events that could lead to drop in mud levels (both in the annulus and the casing bore) ‎[7], overpressure formations from 1700 mtop seepage beds to the top of jeribe formation ‎[8] as shown in fig. 1 khabaz oil field pressure profile, flow of salt water, difficulty in maintaining mud properties and difficulty in achieving cement displacement. h2scontent in the untreated oil from the tertiary reservoirs is 14ppm; in mauddud, it is 200 – 1628ppm; and in shuaiba the content is 218– 880ppm ‎[8] ‎[8] . the challenges that have cause stuck pipe incidence, among other non-productive activates, we should analysis and concentrate on this problem trying to prevent or to reduce it. general stratigraphic for khabaz oil field ‎[7] is given in table 1. https://doi.org/10.31699/ijcpe.2018.4.6 n. s. amin and a. a.alhaleem / iraqi journal of chemical and petroleum engineering 19,4 (2018) 47-53 84 fig. 1. khabaz oil field pressure profile table 1. general stratigraphic for khabaz oil field ‎[7] formation expected top (mater from ground level) anjana 0 upper red beds 1670 seepage beds 1793 saliferous beds 1833.5 transition beds 2009 jeribe 2166 anah 2188 anah/azkand 2206 azkand 2222 azkand/ibrahim 2282 tarjil 2346 palani 2400 jaddala 2421 aaliji 2518 shiranish 2554 mushorah 2686 upper kometan 2721 kometan shale 2809 lower kometa 2855 gulneri 2879.5 dokan 2890 mauddud 2917 batiwah 2992 shuaiba 3102 note: all depths are measured from ground level (gl) by studying several final well reports of the executed wells in khabaz oil field, it was found that the problem of the stuck pipe incident was occurred in several wells for example well number 7, 31, 34, 35.etc.because of marly formation observed in all beds (cap rocks) that caused loss of time and effort and increasing the cost of the drilling due to fishing operations, and sometimes drilling of the side track. the well number 34 was taken as an example for my study to analysis stuck pipe which occurred at injana formation at 1475m during the drill string was pulled out through the section (1620-1475) m unsuccessful fishing operation the well completed by sidetrack drilling to 9 5/8'' casing shoe was set at depth 1840m and trying to cement the casing without successful, then trying to circulate mud with 2500 psi without successful and then 9 5/8'' casing was cemented by perforation operation ‎[7].time distribution of stuck pipe events on the drilling the 12 1/4'' hole that causing increase npt as given in table 2 and compared with table 3 with actual time without stuck pipe. table 2. time distribution of stuck pipe events on the drilling 2 1/4'' hole ‎ [7] hole (in) depth stuck (m) activity during sticking no. days suck freed days sent fishing days spent side track total days 12 1/4'' 1422 reaming/ pullout 1 yes 1 1475 drilling/ pullout 8 no 47 17 72 1840 casing stuck 3 no cemented by perforation spent 15 days 18 total nonproductive (npt) time 91 table 3. time distribution without stuck pipe events on drilling 12 1/4'' hole ‎ [7] hole (in) active time(day): drilling dead time(day): round trip& cir. run casing &cementing install well head & test run tubing &completion total days 12 1/4'' 22 21 43 2.1. mud program the planned program for well khabaz -34 was drilling 12 1/4'' hole to depth 2035m that means the injana formation (thickness 1475m), upper red beds (thickness 112m), seepage beds (thickness 31m), saliferous beds (thickness 159m), and transition beds (thickness 153m) will be drilled in the same hole with salt saturated mud (density 2.02 gram/cc).as given in table 4. n. s. amin and a. a.alhaleem / iraqi journal of chemical and petroleum engineering 19,4 (2018) 47-53 84 table 4. actual mud program khabaz -34 ‎[7] hole size (in) casing size (in) casing shoe depth mud weight (grm/cc.) depth (m) formation 17 1/2'' 13 3/8'' 250 injana 1.05 12 1/4'' 9 5/8'' 1840 upper red beds above seepage 1.65* 8 1/2'' 7'' 2211 maker t13 above jeribe 2.02 6'' 4 1/2'' 2285 azkand 1.08 *this density is high and caused mud losses followed pipe sticking 2.2. easy view diagram and analysis the drilling data information during selected stuck pipe events in well khabaz -34 were analyzed using easy view software to recognize and identifying the causes of the stuck pipe and possible solution. stuck pipe pro software (stuck pipe analysis) pegasus vertex, inc. (pvi) has developed it to calculate differential sticking force, drag, the free point and back-off force, and the potential chances of a pipe or casing getting stuck during pick-up operations additionally, the stuck mechanical analysis and decision flow charts help users determine stuck-pipe situations and take corresponding measures to free the pipe ‎ [9]. the drilling data was recorded using data loggers at the rig site and it has been collected and inputted into easy view software stuckpipepro – torque and drag model computational results a. inputted data in to easy view software the drilling data was recorded from well khabaz – 34 which drilled by the iraqi drilling company and it has been collected and inputted into easy view software (stuckpipepro ) as given following table 5 and table 6 to analysis of stuck pipe incidents : table 5. wellbore intervals (from top down): define the friction factors for each string description i.d. (mm) md (m) friction factor (ff) casing 320.42 250.0 0.20 open hole 390.31 1467.0 0.25 table 6. formation top (m) bottom (m) pore pressure (kg/m3) fracture (kg/m3) permeability (md) porosity wall cake (mm) 250 398 1028.1 2343.7 0.000 0.070 0.0000 398 923 1028.1 2488.7 0.000 0.070 0.0000 923 1467 1049.6 2489.9 0.000 0.070 0.0000 b. results from easy view software the diagrams and tables that results from the software have been displayed and described stuck pipe incidents at well khabaz – 34 that occurred during pick up drilling string form 1724m to 1475m through injana formation which consist of soft siltstone, with streaks of marl and anhydrite, it has properties unconsolidated and marly formation. main drilling potential risks is lost circulation mud, bit balling, and unconsolidated formation. first hole was drilled and cased to depth 250m to protect the poorly consolidated upper sections, continue drilled the second hole with f.w.b.m. density 1.1 gram/cc to 1707m deviated 2° and continued drilling with s.s.m density 1.65 gram/cc. to depth 1724 m, partial mud losses was occurred, drill string was pulled out with over pull from 1724m to 1475m and it get stuck at depth 1475m. margin of over pull the drill string at the surface is 839880 n as shown in fig. 2. so we can see clearly the over pull increasing to the depth 1337.5 m to reach 886392 n and after that depth the value of margin of over pull to be negative value because of stuck pipe effect, stuck forces controlling starts here. fig. 2. margin of over pull there is no chance of getting stuck pipe as shown in fig. 3 from the surface to depth 1337.5 m because of the hole was cased to depth 250m and there are no stuck events factors causes from 250-1337.5m. after that the hole deviated to 2° and partial mud loss resulted from high mud density caused instability the hole and the value of getting stuck increase suddenly to reach to 100% and it is continue to the depth 1475m. n. s. amin and a. a.alhaleem / iraqi journal of chemical and petroleum engineering 19,4 (2018) 47-53 05 fig. 3. chance of getting stuck we can knew the type of stuck pipe event through side forces profile as shown in fig. 4, on the left hand differential sticking side forces value is constant at zero from the surface to depth 1500m confirming no differential sticking pipe force effecting. on the right hand side forces effect on drilling string per joint shows the mechanical force. at depth 250m side force increase sharply to 295n per joint (multiplying number of joints by force) due to 0.3° inclination effect on drilling string and at depth 1337.5m side forces increase to 200-225n per joint. due to tight section and deviated hole getting mechanical stuck pipe. fig. 4. side force profile the axial drag for pick up the drill string and tension limit as shown in fig. 5 at the surface the maximum allowable load hook -load pick up is 523,901 n, current hook load pick up is 1186473 n trying to get the string free , the tension limit is 2,210,000 n to avoid string getting parted. the maximum allowable , current load hook -load pick up and decreases due to drug forces effect on drilling string, at the depth 1337.5m , tension limit decreases to zero, and getting stuck. the previous figures are explained by the following table 7, table 8, table 9, and table 10. fig. 5. axial drag for pick up and tension table 7. summary – chance of getting stuck current hook load pick up (n) maximum allowable hook load pick up (n) maximum hook load capacity (n) allowabl e margin of over pull (n) chance of getting stuck tensile strength (%) chance of getting stuck maximum hook load capacity (%) 1186473 523901 4448220 886392 100 0 table 8. summary – chance of getting stuck at top of each pipe m.d. (m) pipe (od x id) margin of over pull (n) margin of over pull w/o pinning force (n) chance of getting stuck (%) 0.0 5 x 4.275984 839880 839953 0 1337.5 8 x 2.812992 886392 -886384 100 m.d. (m) axial drag pick up (n) tensile limit(n) side f. (n) (per jt.) side f. (diff. stick) (n) (per jt.) chance of stuck (%) margin of over pull(n) contact area (in2/ft.) 1467.0 662530 0 226 0 0 662530 0.00 n. s. amin and a. a.alhaleem / iraqi journal of chemical and petroleum engineering 19,4 (2018) 47-53 05 table 9. free point calculation distance between 2 pulls (mm) t1 pull (n) t2 pull (n) length of free pipe (m) 105.00 378431 456784 1038.3 table 10. back off calculation 80% of max torsional limit at backoff depth in tension (right turns) hydrostatic pressure at depth of back-off (kpa) weight in mud of free length of dp + block (n) weight indicator tension at neutral point (n) 80% of rightward turns for applying leftward twist (left turns) 10 18903.8 262446 262446 8 3results , discussion and recommended ideas the selected proper fluid for each interval after giving the consideration to objectives, risks, technical suitability and cost goals which can be summarized as: construct wells suitable for the proposed completion design ,provide hole stability, provide primary control and avoiding stuck pipe. depending on the type of layers that consists the upper second hole (injana formation, and upper red beds) it is not necessary to use salt saturated mud (density 1.65 grm/cc.) which caused partial mud losses. the challenge of lost circulation events could lead to drop in mud levels, then cuttings will settled out around the bottom hole assembly, and may the cuttings will act as a packer, and effect losses below them as loss zones may be at low pressure, causing of differential sticking. and also, the presence of multiple marly and silt beds/formations in the absence of control on the formation by the column of drilling fluid causes the instability of the wellbore, mechanical stuck pipe events will be occurred. when the pressure on transition beds was 3724 psi with safety factor 200 psi, the density of fresh water bentonite will be 1.35 gram/cc that are enough to control the well during drilling operations. therefore, an idea can be suggested is to drill the second hole to the depth of 1700 meter (top of upper red beds) with f.w.b.m. density (1.21.35) gram/cc. and always keep the pipe moving as a rule and have enough open hole volume below the bit to accommodate the whole treatment and avoided stuck pipe. set second casing shoe at this depth, then third hole drilled with s.s.m. density (1.92.20) gram/cc. to top of jeribe. recommendations for mud formulation will be according to what be mentioned in table 11. depending on the above observations, the well can be redesigned with an explanation of the risks and challenges encountered during drilling. table 11. mud formulations, and recommended properties hole section 17 1/2'' 12 ¼'' 8 1/2'' depth to (m) md 200 )1700 2177 mud type pre-hydrate bentonite pre-hydrate bentonite /polymer salt saturated kcl/poly mer mud density (g/cc) 1.05 – 1.10 1.21.32 1.92.20 funnel viscosity(sec/qt) 60 70 50 – 60 60 -70 plastic viscosity (cp) yield point (lb/100 ft2) 25 30 20 -25 30 -45 initial gel strength (lb/100 ft2) 8 10 7 -9 7 -9 10 min gel strength (lb/100 ft2) 10 20 10 -18 10 -16 6 rpm * 9 -14 9 14 api fluid loss (cc/30 mins) n/c <10 before rih with casing < 5 ph 9.0 -10.0 9 10 9 10 ca++ < 200 mg/l < 200 mg/l < 200 mg/l sand % < 1% < 1% < 0.5% lgs, % vol. < 7 % < 7 % < 7 % chloride, mg/l > 15000 >18000 kcl, % 3% 5% diesel/oil, % mbt (ppb) 30 15 – 20 <10 4conclusion 1the major factor to avoid risks and problems is selecting the more suitable mud type and mud properties. for example: injana formation interval (surface – 1670m) which consist of soft siltstone; with streaks of marl and upper red beds formation interval (1670 – 1793m) which consist of alternating anhydrite(white, hard, massive),siltstone; (red-brown, soft), limestone markers (r1-r9); ( medium hard, pyritic, marly) and marl; (grey-blue, soft ) fresh water bentonite (pre-hydrate bentonite) is the suitable mud type to use to avoid mud loss and keep the hole stability 2analysis of software results determined the type of stuck pipe which is the mechanical sticking at injana formation, determined free point calculation and back off calculation. 3analysis of software results show us the elastic and the plastic point for the drilling string and can work safely to apply the over pull and free the pipe under the point 2210000n 4penetrex which is a mud additive can be used as a good option for preventing bit balling and enhance the drilling rate, at top of lower fars, a treated mud with md (drilling detergent) with 4 gal/100 bbl. (1.0 l/m3) to prevent bit balling and improve drilling rates. n. s. amin and a. a.alhaleem / iraqi journal of chemical and petroleum engineering 19,4 (2018) 47-53 05 5optimizing casing set design to deal with problems separately. size of 9 5/8'' casing should be seat on the upper seepage beds as executed in well khabaz -34 and not as the pervious planning at the upper of jeribe. 6it is important to keep the drilling solid concentration in mud always under control by using solid control configuration such as desander and desilter 5abbreviation npt: nonproductive time ppm: part per million kz: khabaz gram/cc.: gram/cubic centimeter in: inches m: meter pvi: pegasus vertex inc. ff: friction factor i.d.: inside diameter md: measure depth md: millidarcy s.g.: specific gravity f.w.b.m.: fresh water bentonite mud s.s.m.: sult saturated mud cp: centypoice lb: pound psi: pound square inch gal.: gallon bbl.: barrel ft: feet rpm: round per mint references [1] warren, j.e.1940. causes, preventions, and recovery of stuck drill pipe. api-40-030. weakly, r.r. 1990. use of stuck pipe statistics to reduce the occurrence of stuck pipe. presented at spe annual technical conference & exhibition, new orleans, 2326september.spe-20410-ms. [2] bradley, w.b. jarman, d., plott, r.s.et al 1991. a task force approach to reducing stuck pipe costs. presented at the 1991 spe/iadc drilling conference, amsterdam,11-14.spe-21999 [3] yarim, gokhan; uchytil, rodney j.; may, richard b.; et al.2007. stuck pipe prevention – a proactive solution to an old problem. present at spe annual technical conference &exhibition, anaheim, california, 11-14 november. spe-109914-ms [4] muqeem, m.a., weekse, a. e., and al-hajji, a. a. 2012. stuck pipe best practice – a challenging approach to reducing stuck pipe costs. presented at spe saudi arabia section technical symposium and exhibition, al-khobar, saudi arabia, 8 -11april.spe160845-ms. [5] ferreira, ana paula l. a., carvalho, daltro j. l., rodrigues, r.m.et al. 2015. automated decision support and expert collaboration avoid stuck pipe and improve drilling operation in offshore brazil subsalt well. presented at the offshore technology conference, houston, texas, 4-7 may. [6] salminen, kent, weatherford, cheatham, curtis, weatherford smith, mark, weatherford, valiullin, khaydar, weatherford 178888-pa spe journal paper – 2016. stuck pipe prediction using automated realtime modeling and data analysis. [7] khabaz final well reports from north oil company, field division, drilling department. [8] reservoir petroleum engineering department north oil company database. [9] drilling software /stuckpipepro'' stuck pipe analysis’’ by: pegasus vertex, inc. http://www.pvisoftware.com/stuckpipepro-stuck-pipeanalysis.html https://www.onepetro.org/conference-paper/api-40-030 https://www.onepetro.org/conference-paper/api-40-030 https://www.onepetro.org/conference-paper/api-40-030 https://www.onepetro.org/conference-paper/api-40-030 https://www.onepetro.org/conference-paper/api-40-030 https://www.onepetro.org/conference-paper/api-40-030 https://www.onepetro.org/conference-paper/spe-21999-ms https://www.onepetro.org/conference-paper/spe-21999-ms https://www.onepetro.org/conference-paper/spe-21999-ms https://www.onepetro.org/conference-paper/spe-21999-ms https://www.onepetro.org/conference-paper/spe-109914-ms https://www.onepetro.org/conference-paper/spe-109914-ms https://www.onepetro.org/conference-paper/spe-109914-ms https://www.onepetro.org/conference-paper/spe-109914-ms https://www.onepetro.org/conference-paper/spe-109914-ms https://www.onepetro.org/conference-paper/spe-160845-ms https://www.onepetro.org/conference-paper/spe-160845-ms https://www.onepetro.org/conference-paper/spe-160845-ms https://www.onepetro.org/conference-paper/spe-160845-ms https://www.onepetro.org/conference-paper/spe-160845-ms https://www.onepetro.org/conference-paper/spe-160845-ms https://www.onepetro.org/journal-paper/spe-178888-pa https://www.onepetro.org/journal-paper/spe-178888-pa https://www.onepetro.org/journal-paper/spe-178888-pa https://www.onepetro.org/journal-paper/spe-178888-pa https://www.onepetro.org/journal-paper/spe-178888-pa http://www.pvisoftware.com/stuckpipepro-stuck-pipe-analysis.html http://www.pvisoftware.com/stuckpipepro-stuck-pipe-analysis.html n. s. amin and a. a.alhaleem / iraqi journal of chemical and petroleum engineering 19,4 (2018) 47-53 05 ستعصاء أنابيب الحفر في حقل خباز النفطيإتحليل الخالصة انابيب الحفر التي تعتبر من المشاكل تواجو عميات حفر اآلبارالعديد من المشاكل ومنها مشكمة استعصاء الشائعة جدا في جميع انحاء العالم في صناعة الحفر البترولية مسببة زيادة في الوقت الغير المنتج وخسارة في الوقت والجهد والزيادة في الكمفة نتيجة العمميات االضافية من التحرير وانتشال انابيب الحفرالممتصقة اضافة .ي حالة عدم نجاح عمميات االنتشالر الجانبي فالى عمميات الحف ان الحفر في حقل خباز النفطي يواجو العديد من التحديات والمشاكل من بينها فقدان دورة سائل الحفر ، .التجويف مسببا استعصاء االنابيب وتدفق المياه المالحة أثناء الحفر، وتهدم جدار لذلك، فإن الحفر في حقل خبار النفطي يكون صعبًا جدًا بسبب المشاكل التي تؤدي إلى زيادة في الوقت لدراسة مشكمة استعصاء انابيب الحفر وتم إجراء تحميل البيانات 43-الغير المنتج. لذلك تم اختيارالبئر خباز ( يعرض من خاللو الرسوم والجداول ( stuck pipe pro المتوفرة باستخدام برنامج التحاليل الرسومية والتحاليل بشكل سهل ثم نوقشت النتائج لتحديد أسباب ونوع األستعصاء . وأخيرا، تمت التوصية لتحديد نوع سائل الحفر المناسب وخصائص سائل الحفر الريولوجية ، وتحسين تصميم إختيار منطقة إجالس البطانة لمحد صاء أنابيب الحفر .او تقميل من إحتمال إستع iicpilraqi journal ot chemical and petroleum engineeringvol.10 no.3 (septembef 2009) 5'l-56 i s s n : 1 9 9 7 4 8 8 4 a study of forward osmosis using various drawing agents adit a. al-hemiri-, adil o. sharil"and mustrfa hussein 'chemical eneinee ng departnent cotlege of engineenng uniwrsity of bashdad ituq " center for osnosis research & awlications, uniwrcw of suwy uk abstract this rcseqtch was ained to st1.t4, the osmotic eljiciency afthe droo solutions and the factors alfecting the perfomance of forya osnosis process. the dftr,,r' solutions 6ed 'ere masnesiun sufate hy.hate (mqso4.7h2o), patassiun chloride (kcl), calciun chlotide (cacl2), and amnoniun bicarbonate (nh4hc)3). it v,as found that wqtet tltx in.reases vith increasing *ate solution concentrution, and feed solution flow tate and dec rcases w ith incrcasing dnlr solution fow rate and feed solution concentration. and also found that the efrciency of the .lrn solutions is in the caclr> kci > nr!hco3> mgsoa.th,o relrdrdr: forward osmosis, draw solution, desalination lntroduction desalination refers to the wide range of processes designed to remove salts from waters of different qualiti€s desalination technolog/ is in use throughout the world for a wide range ofpurposes, including providing potable ftesh water for domestic and municipal pur?oses, treated water for industrial processes, and emergency water for r€fugees or military operations because of growing conc€ms about water scarcity and quality, and disputes over allocations of scarce water resourc€s, a tremendous amount of effort has been devoted to developing technologres to desalinate the vast quantiiies of seawater available n l. to reduce the cost of existing desalination technologies, it is prudent to focus on what makes current technologies so expensive. energy is indisputably the most significant contributor to the cost of desalination. hence, reduction in energj usage is the primary objective io making desalination nore affordable [2]. forward (or direct) osmosis (fo) is a process thal may be able to desalinate saline water sources at a notably reduced cost. in lorward osmosis, like ro, water transdofs across a semi-dermeabl€ membrane that is impeirn*bl€ ro sah. however, instead ofusing hydraulic pressure ro create tbe driving force for water transport throueh the nenbrane, the fo process utilizes an osmotic pressure gradient. a "dra 'solution having a significantly higher osnotic pressure than the saline feed warer flows along the permeate side of the membrane, and water naturally transports across rhe membrane by osmosis. osmotic driving forces in fo can be significantly greater than hydraulic driving forces in ro, potentially leading to higher water flux rates and recoveries. the lack of hydraulic pressure may make the process less expensive than ro, while the minimization of brine discharge reduces the environmenial impact of the desalination process [3]. previors forward osmosis efforts in 1965, batchelder [a] described a process of adding volatile solut€s, such as sultut dioxide, to seawater or fteshwater io create a solution which may be used in a forward osmotic process to extmct wat€r from seawater. the suggested membrane to be used in this process was cellulosic in nature. other exampl€s in the palent i j c p e v o l . 1 0 n o . 3 ( s e p t e m b e r 2 0 0 9 ) d e s c r i b e d r h e x . e o f c a n o r r o o r a s a m e m b r d n e m a r e r i a l . c a f i i e d o u r u n r i t r h e d r a $ s o t u r i o n i s s u r n c r e n f l y d r t u t e . a r t r h i c h p o i n t l h e \ o t a r i t e j o t u r e i j removed by heat;ng and/or a; srripdins. in 1472. frant [5] descrjbed ; m;rhod or rorward o s m o s i s u s i n g a p r e c i p i t a b t e s a t r . i n r h i s c a s e a t u m i n u m s u f a r e . a s r h e _ d r a w 5 0 t u t i o n s o t u t e . j o o s i n g o s m o s i s o f w a r e r a c r o s \ l h e m e m b r a n e . r h e d i t u r e d d r a $ s o r u u o n \ r a s d o s e d . q i l h c d l c i u m h y d r o x i d e . t e s d i n g r o r h e p r e c r p a n o n o t a t l ' m i n u m h y d r o x i d e a n d c a t c ; u m ( u t f a r e . _l-i.f*;"'"1e is remo!ed b) srandard merhods reavins rne rresh producl waler. ercess cajciu,n hydrorjde from rne.precrprtalion s,ep can be removed by dosing wirh s u l l u r i c a c i d o r c a r b o n d i o r i d e . t { h i c h p r o d u j c , ( a r c r u m s u r l a t e a n d c a l c i u m c a r b o n a r e p r e c i p i t a r e s . r e s p e c r i v e t ) . l h r s s t e p r e q l i r e d a d d i t i o n a l s o t i d r e m o \ a l a n d t e d t o neutral ph in the product waaer. the mernbrane used rn the patenr was cetlulose acerate membrane. in i975, kravath and davis t6l described a process of seawater desalination achieved by form.d osnosis of water across a cellutose acetate menbrane. initial tests were run wirh a dialys;" ce wirh gtucose as the draw sorule a1d sea$ arer as the feed. additional lesn $(re run with glucose dissolved in seawater as a drarv soruron. e&ergency lifeboars w€re considered as apossible use of rn-e. process in $trch seawarer was broughr abodrd a i r e b o a t a n d g t u o s e w a s d d d e d . a d d i l i o n a l s e a $ a r e , ! r a s p a s s e d r h r o u g n a d , j t y < i s u n i r t e a d i n g r o o s m o . t a n d a o l u u o n o t l h e . e j $ a l e r g l u c o s e d r a $ " o t u l i o n . u p o nd j l u t i o n . t h e . . , . i n i r y w a s r e d u c e d r o a t e v e l t \ h e r e rngestron wa: po.sible for shon tem conrumplion. the rrar sneet cettliose dcelate membranes did nol pertorm weil in terms satr rejeciion. hollow fiber membran€s were also tried and resutrs improved. draw sorure r€moval was nor considered because the sorute was intended for ingestion. in 1994 herron t7l were awarded a parenr on a membrane mod|]e and a method to concenrrate ftufu jurces and wrnes. in the summary ofthe inv€ntion, the rnventors reconnlended rhe us€ of 50_85 w1. %o sugar solut'on as the drarv sotution. in 2002, mccinnis [8] described a merhod of forward osmosis using a combination of draw sotutions across several senr-pcmeable membranes. this parent c o m b i n e d t h e o r s o f d m s s o t u l i o n r c c y c t e w l n a n osmo!icalll el.i -11 draw solurion lo increase , c(oved . the two-stage io prccess takes advantage of the t€nperalure dependent solubilities ofthe solut€s, in this case potassium ilrele (kno3) and sutturdioxide (so2). seawater was he.red and led to the fo membrane unit where a heated solution of saturated potassium nitrare s€rved as the dfaw solution. the diluted draw soruuon was sent !o a nerv chamber where it was cooled by i n c o m i n g s e " \ . , . . s h i c h w a s s i m u t t a n e o u s t y h e a t e d r o l h e a p p r o p n j l ( f e d r e m p e m t u r e . u p o n c o o l i n g . . " i g n i f i c a n r p o r ' i i o i l h e k n o 3 p , e c i p i r a t e s o u r o t s o l r ' l i o n . r e d u c i n g l h e o s m o | | c p r e s s u r e . \ e n . r h e d i t u l e o d r . s o h e d . s o 2 _ a c r e d a s r h e d r a w s o t u l i o n . t h e d i t l r r e ^ r \ u r i s o r l l r o n h a d a t o w o s m o r i c p r e s s u r e i l c o n p a r i s o l wrrn ine saturated soj soturion. and waler diftused a c r o s s r h e m e m b r d n e $ h i t e r h e k \ o j $ d s r c j e c r e d . t h e surtur d'oxid€_$as rhen remored rhrolrgh sraniard mean., r e a \ r n g p o t a b l e q a r e r . a s o t u l e s $ e r e r e c l c l e d i n l h € in 2005 jeffrey i2l desc.ibed a forwaro osmosrs process ror seawarerand brackish warer desalinarion. the process used a.rl'x-onium bicarbonate dmw solulion ro extract waler ftom saline feed water across a semi_ permeable polymeric membrane. very larsc osmolc presslre5 gener,red by rhe hj8hty sotubte ammonium b i c a r b o n d l e d m $ s o l u r l o n ) i e t d h i g h t \ a l e r f l u r e s a n d c o u l d r e s u t l j n \ e r y l r i g h t e e d w d r e r r e c o \ e r i e s . l p o n moderate heating, ammonium bicarbonate decomposed into ammonia and carbon dioxide $ses thai could be sepamted and recycled as draw solutes, teaving the fresh p r o d u c j . . w a r e r . f x p e r i m e n r s $ : r h a t a b o r d r o r y _ s c a t e f o u n i l u l i l i t i n g a n r t s h e e r c e t j u t o s e l r i , a c e r a l e , . , e m o r m e demonstmted hish produd ware. flux and relativety high ^rl _2!0q. a novet osmoril membrane b;oreacror t u . m b r i l p r e s e n t e d b y . n d r e r [ q l . i h e s y s r e r u t i l i t e j a subterged foflard osmo)is (fo) membrane modute r n s r d e a b r o r e a c l o r . t h r o u g h o s m o s i s . w d r e r i s r r d n s p o n e d rom lhe mixed liquor across a semi_per.l1eabte membrane, and into a draw soturion (ds) wirh a highef o s m o l j c p r e s s u r e . t o p r o d u c e p o r a b t e $ a r e r . t h e d i t u r e d u 5 , r s r r e a l e d i n a r e v e h e o s m o s i s ( r o j u n i r : r h e b ) , proouo rs a reconcentrared ds for reuse in the fo p r o c e 5 s . m e m b r a n e t o u t i n g u a . l o n r r o e d $ i r h o s m o r ' c backl\a:hing. the fo membrdne was found r^ ,-r-eseo oforeanic carbon ana ro;" "r "^.""i,nl_" -,"ji", t h e o s \ 4 b r p r o c e s . r b i o r e a c r o r a n d i o m e m b m n e ) ; a s lound to remove greaier than 99% oforeanic carbon and o 8 o ; o f a m n o n i u m { i r r o g e n . r e s p e c r , , e l l : . u g e e s r n g a b e u e r c o m p a t i b i l i r y o f r h e o s m b r \ ^ i r h d o $ n ; r r e d m k o sysrems than convenrional membrane bioreacrors. the ideal drarying rgenr for forward osmosh ' f h e d m w i n g a g e n r s m u s r h a \ e a h i g h o s m o r i c e f l ; c i e n c ) . n a m e l y h i g h s o l u b i t i r y i n s a l e r a n d r e t a r i ! e t y t o $ m o l e c u l a r w e i g j r l , w h i c h c a n t e a d r o h i a h o s n o r i c pressures [21. . r . " g a r d r e s s o t t h e a p p t ; c a r i o n . o s m o l ; c a g e n t . s h o u t d r 0 e a r r y b e r n e n . s l a b l e . o f n e l r r a l o r n e a r n e u ! r u t p h . a n d n o n . l o x i c . t h e l s h o u t d n o r d e g , a d e t h e m e m b r a n e c h e m r l d l l ) f r h r o u g h r e a c r i o n . d i s s o t u r i o n . o r a d s u r p . r o n / o r p h y . i c d l l ) { f o u l i n g ) a n d s h o u t d h a v e m i n i m a t e f f e c r s on the environm€nt or human healrh. theyshoutd also be inexpensrve! very sotuble, and provide a hish osnotrc ijcpe vol.'10 no.3 (september 2oo9) 52 a.til a. al-henii, adil o.sha4f and pressure. for specifio applications, additional criteria will apply, e.g. in desalination concept requires the dmwing agent to be easily (both ftom a physical and enereeric standpoint) and completely recoverable ftom warer [10]. experimental work figures i and 2 describes the apparatus used in laboratory-scale fo experiments fig. i sohematic diagram ofspiml wound forward osmosis process fig. 2 sohematic diagram offlat sheet forward osmosis process ucpe vol.10 no.3 (september 2009) 53 a shj) aj i atuad osnat, lj:ing yatiau, druwtab ̂ aea6 the experinental work consists of two parts. the first paft is to show the effecr of operating conditions on the $ a e r i r l x n i h e t f ( . h r m e r b m r e c o n s t r j c t e d a s spiral wound module and the second part is to show ihe efficiency of different draw soluiions in tfc-ulp membrane constructed as flat sheet module [] 11. the experimental procedure is adraw and feed solutions w€re pr€pared in the evf glass vessels by dissolving rhe solid salt in 25 lite. of bthe oullet valve ofthe feed vessels lvas open to le! rhe solutions fi1lthe whole pipes ofthe sysiem. cthe feed solurion drawn ffon rhe feed vesselby rn€ans of a centrifugal pump to pass rhrough filrers (5 l1n) to rcmove macromolecules, colloids and suspended solids dthen the feed solution is introduced into the permeator (onthe feed side) by neans ofahigh pressure pump ethe draw solution 's fed tothe forward osnosis unit on flhe feed and draw solurion flow tangential to rhe membrane in the sane direction (co-curent flow). g-the sieady state operation took between i to 1.5 hr to achieve. during this time the conductivitjes (concentariono ofthe feed solution, draw sotution. feed solution outlet concentration and draw solution outtet concentration were measured bylhe conducrivity merer. ha*er recording the results, the solution was drained through a drain valve. the whole sysren was washed by deionized water. now, the system is ready for rhe next results and discussion tx'c-hr membrane effect of feed solution flow rate otr lyater flux figure 3 shows the effect of sodiun chloride feed solulion flow rate on water flux, for nagnesium sulfate hydrate draw solution at different concentrations of mgso4.7h2o. increasing the flow rare of feed solution caused decreasing the concentratio! buildup in the vicinity of the membran€ surface, which leads to decr€asing in osnotic pressure in the feed solution side a r d r h e n r e \ u l r i n g i n i r c r e a . i n s r h e d r i v i n g f o r c e r ^ n ) . le. increasing th€ potent water flux fig. 3 water flux with feed solulion flolv rare ar ditrerent draw solution concentrarion d|aw solution rate = i l,4rr and feed solunor concentrarion = 2.5g/l effect of draw solution flow rate on waterflux figure 4 represenls the effecr of draw solution flow rare on water flux, decreasing ofthe d.a!v solulion flow rate caused inc.easing the concentrarion buildup in the v r c i n i r ) o f t h e m e m b r a n e ' u r f a c e . f t i s l e a d s r o i r c r e a s i n g the osmotic pressure in the draw solution side and lhen increasing the water fl ux. : g s desolutionflowralo fig.4 water flux w;th drawsolution flow rate at differen! draw solution concentrarion feed solution flow ratf60l/hr and feed solution concentratjon : 2.5 g/l u c p e v o l . 1 0 n o . 3 ( s e p t e m b e r 2 0 0 9 ) ad a. ai_h".trt, a effect of feed solution concedtration on water flux figure 5 illustrate tbe effect ol feed soruuon concentration on water flux, increasing the feed solutjon concenlration leads to decreasing the driving force and tben decreasing the wate. flux as shown in figure 5. tfc-ulp membrane effecf ofthe type ofdraw solution the draw solution solute must have high osnotic efficiency, meaning that it has ro be highly soluble in water and have a low molecular weight in order to generate a high osmotic pressure. higher osmoric pressure leads to higher water flux and feed water using diferent rypes of draw solurions in order to find ihe best one which has the higb€st osmotic pressure to eive hieh warer flux, it was found that the order of higher j. rc"crr>j" ccrr>jrrn rsco)>j. @sso.rruo) calcium chloride (caclt has ahigh water flux because ir has highesl osnotic pressure (driving force) than other mat€rial studied. this is shown in figur€ ?. tabl rysical properties ofthe draw solution solut€ 25oc&90 g! i t 0 9 9 5 9 5 2 kcl 7,1.56 21.(f 53.907 ) nrllhcot l 5 7 l l 4 1 8 4 6 mgsor?hro 1 0 r 5 9 ! = fig. 5 lvater nux with feed solution concentration for different draw solution concentration draw solution rate =3 l/hrand feed solurion flov rate = 601/hr eff€ct ofdraw solution concentrrtion on water llux increasing rhe drus solution concenrrurion will increase the driving force (an) and then increasing the water flux, this is shown in figure 6. ore so dion lon.ed€uon q\ f i g . 6 $ a r e r n u x s i l h d r a $ s o l u r i o n c o n c e n l r u l i o n a l different draw solution flow rates feed solulion flow rare 60l,hr and feed soluli!,' concentrarion = 2.5 g/l dftu soubm ccrced?tiln g\t fig.7 water flux with draw solution concentration for difierent draw solurions d'at\ solulion rare 3 l/hrand, solurion flow mte 601,ftr and feed solution concentration = 2.5 g,4 ijcpe vol.'10 no.3 (september 2009) t i a sludr oj fotuar.l oshosis usihg ra, ous conclusions the foilowing conclusions could be drawn 1iom the present research il ll: iforward osmosis can be us€d to sepa.ate water rrom a concentrated slream (e.e. saljne watet that contains water and satt where rhe war€r transfer fio|n low concenrrarion (feed solution) to high concentration (d.aw soluiion) 2the water flux produced from the osmosis cell increases by incr€asjdglbe conc€nrrarion or draw solutions and increasing the flow rare of feed solution and decreases by jncreasing the concentration of feed sotution and increasing the flow rare of draw solutions. some results for m g s o " . 7 h ? o i n " p i r a t $ o u n d m o d u , e a r e g i v e n in the followingtable. cr ff cd j* 60 9 0 3 6 . 4 6 1 60 90 l 6.089 t2 9 0 l 3.562 0 . 5 6 0 1 0 3 3 . 8 3 8 0 . 5 6 0 9 0 l 5 4.623 lspiral-wound membrane which is normally used in reverse osmosis process can be modified and a p p l l e d a " a g o o d a l r e r n a r i \ e i n d i r e c r o 5 m o , t 4the best draw solulion was the sotution that gives higher warer flux. it was found thar lhe order ofwaier flux for the reagenrs used !vas: caci2 > kci> nh4hco3 > msso4.7h2o cd draw solution concentrafion dl cr feed sotution concentralion tl fd dmw sollrion now rare i hr f, feed solurion flow rare i hr j* watef flux l,lr.m? r osmotic pressure ba, tfc thin film composite hr high rejecrion ulp ultra low pressure references l) .heath€r cool€y. peter h. cleick, and ca.) wolff, (2006), desalination, wfth a grain oi salt" alonzo printing co., tnc. p 9. 2 , , : f t l , * r o b e n . 1 . . a n d m e n d c h e m . r . , (2005)," a novet nnronia_carbon dioxide forward (dnect) osmosis desaljnation process " d e s a l i n a t i o n , 1 7 4 , p . 1 l t . 3) l:f"v, n., robert, 1., and menachen, e., (2006),', desalination by anmonia,carbon dioxide forward osmosis: lnfllence of draw and feed soturion concentrations on process peribnnance,,, journal of membrane science, 2 7 8 , p . 1 1 4 " 1 2 3 . 4) batchelder, c.w., (1965) .,process for the d-emineralization of watef'; us patenr 3, 171, 799. s ) f r a n k , b . s . , ( r 9 7 2 ) . , d e s a t i n a t i o n o f s e a water", us patent 3, 670. 897. 6) kravarh, r.e., and davis, j.a., (1975)," desalination of seawaler by directs osmosis,,, d e s a l i n a t i o n , 1 6 . p . 1 5 l 1 6 i . ? j h € r o n . j . r . . b e a u d d . t . u . . j o c h u . r s . c . e . . a n d \ 4 e d , n a 1 . e . . ( t q a 4 l o s m o r : c c o n c e f t r a n o n j p p a r a r u r a n d m e r h o d f o r d i r e c r o i m o 5 i s concentration offruitjuices,,, us patenr j. 281, 4 3 0 . 8) mccinnis, r.l., (2002)..osmotic desahnaoon process", us patent 6,391,205 bl. 9) 4ndrea a, tzahi y, eric a, and amy e, (2009)," the forward osmosis membrane bioreactol a low fouling ajtemariv€ to mtsr processes", desalinarion, 239, p.t0_21. t0) jam€s e. miller and lindsey r. evans., (2006) "forward osmosis: a nelv approach to watel purification and desalinarion" sandia nauonal laboralories, p 3. l l ) \ , i j n a f a h . t 2 0 0 9 ) . " a 5 r u d ) o f f o r u a r d o s n o s i s using various drawing agenrs', m, sc. thesis, baghdad universjty. i2) penf, r., and creen, d., (1997) ,'perry,s chemical engineers, handbook.,, 7s ed.; mccrawhill: new york, p.22_i4. i j c p e v o l . 1 0 n o . 3 ( s e p t e m b e r 2 0 0 9 ) 56 iraqi journal of chemical and petroleum engineering vol.15 no.2 (june 2014) 1525 issn: 1997-4884 study the performance of low cost material (peanut hulls) for dye adsorption using inverse fluidized bed najwa saber majeed and shaimaa abood alwan chemical engineering department, college of engineering, university of baghdad abstract the present study dealt with the removal of methylene blue from wastewater by using peanut hulls (pnh) as adsorbent. two modes of operation were used in the present work, batch mode and inverse fluidized bed mode. in batch experiment, the effect of peanut hulls doses 2, 4, 8, 12 and 16 g, with constant initial ph =5.6, concentration 20 mg/l and particle size 2-3.35 mm were studied. the results showed that the percent removal of methylene blue increased with the increase of peanut hulls dose. batch kinetics experiments showed that equilibrium time was about 3 hours, isotherm models (langmuir and freundlich) were used to correlate these results. the results showed that the (freundlich) model gave the best fitting for adsorption capacity. different size ranges of peanut hulls (pnh) were fluidized by a downward flow of an methylene blue dye dissolved in water in an inverse fluidization mode. in the inverse fluidized bed experiments, the hydrodynamics characteristics, the effect of initial methylene blue concentration co 5, 10 and 20 mg/l, particle size 1.18-2, 2-3.35 and 3.35-4 mm, mass of adsorbent 25, 60 and 80 g, superficial fluid velocity 0.016, 0.019 and 0.027 m/s and effect of chemical modification were studied. the optimum conditions of adsorption in inverse fluidized bed were initial concentration was 5 mg/l, particle size was 1.18-2 mm size, mass of pnh is 80 g and superficial fluid velocity was 0.019 m/s. also the adsorption capacity of pnh increased after modification by nitric acid. uv-spectrophotometer was used to determine the methylene blue concentration. keywords: wastewater treatment, adsorption, peanut hulls, dyes removal, inverse fluidized bed. introduction one of the major environmental pollution is wastewater. wastewater comes from homes, commercial establishments, industries and public institutions which use water for various purposes. this polluted water comes from the domestic and also from the industries because of the increase of population and industrial expansion especially in the developed countries. contaminants such as heavy metal, cyanide, toxic organics, nitrogen, phosphorous, phenols, suspended solids, color and turbidity from the industries and untreated sewage sludge from the domestics became a great concern to the environment and public health. wastewater from food coloring, cosmetics, paper and textile industries is polluted by dyes. when those iraqi journal of chemical and petroleum engineering university of baghdad college of engineering study the performance of low cost material (peanut hulls) for dye adsorption using inverse fluidized bed 16 ijcpe vol.15 no.2 (june 2014) -available online at: www.iasj.net colored effluents enter rivers or any other surface water systems, they upset biological activities [1]. ground-water systems are also affected by these pollutants because of leaching from the soil. dyes can cause allergic dermatitis, skin irritation, cancer and mutation [2]. adsorption has been found to be a successful technique for controlling the extent of water pollution due to dyes, metallic species, surfactants and other organic pollutants ([3], [4] and [5]). as a technique in water pollution control, adsorption requires less investment. the design of the necessary equipment is simple and such equipment can be operated easily. in these respects, adsorption is more efficient and convenient than other conventional treatment techniques. activated carbons are conventionally used for the removal of contaminants from liquids and gases because of their structural, textural and sorption peculiarities ([6]; [7] and [8]). however because of their high cost, activated carbons are now being replaced by other low-cost materials. in addition, activated carbons suffer losses of approximately 15 – 20 % during the regeneration process. various other nonconventional adsorbents like fuller's earth and fired clay, silica [9], biogas residual slurry [10], fe3+/cr3+ hydroxide sludge [11], china clay [12], peat moss and rice hulls [13] , coconut husk [14] and fly ash [15] have been reported as efficient adsorbents in removing color. many researches are directed to find low cost adsorbents for clarifying colored effluents. agricultural residues were found to be effective adsorbents, which can be used once as such and then re-used as a fuel by combustion [16]. the ability of using peanut hulls as dyes adsorbent was investigated in this study using batch mode and inversed fluidized bed mode.inversed fluidized bed is a pilot plant used in case of the particle density is less than the fluid density [17], and the hydrodynamics characteristics with some variables such as concentration change, mass of pnh, flow rate and chemical modification were studied. in batch experiments, equilibrium modeling was carried out by langmuir and freundlich models and a correlation between the two isotherms and experimental data was investigated. experimental work materials adsorbent peanut hulls were collected from the local market. the collected biomaterial was extensively washed with tap water to remove soil and dust, sprayed with distilled water and then dried in an oven at 80 ˚c to a constant weight. dry biomass was crushed and sieved to different particle sizes; some of this biomaterial were modified by steeped in dilute nitric acid solution (1% v/v) overnight before being washed several times with distilled water and dried at 80 ˚c and then preserved in the desiccators for further uses. characteristics of peanut hulls are shown in table 1. table 1: physical characteristics of peanut hulls color light to dark brown oder essentially none moisture 6.5% bulk density 68 lb/ft 3 carrying capacity for water 51%-52% absorption of water 168%-169% adsorbate methylene blue (ci 52015) was used as adsorbate, which is a heterocyclic aromatic chemical compound with the najwa saber majeed and shaimaa abood alwan -available online at: www.iasj.net ijcpe vol.15 no.2 (june 2014) 17 molecular formula c16h18n3scl, and wavelength 664 nm. experimental modes two types of experiments were carried out: 1batch experiment 2inverse fluidized bed experiments 1) batch experiments batch experiments were used to obtain the equilibrium isotherm curves and then the equilibrium data. all experiments were carried out at 25 ˚c, rpm =150 and ph =5.6. five 1 liter flasks were used; each flask contained 600 ml solution with an initial mb concentration of 20 mg/l (which was prepared by dissolving 0.02 gram in 1 liter of water). peanut hull doses that were 2, 4, 8, 12 and 16 g, respectively were used in the five flasks. samples were collected from the flasks and tested using uvspectrophotometer (shimadiza – 160) and wavelength 664 nm. 2) inverse fluidized bed experiments column experiments were carried out for measuring hydrodynamic characteristics and for measuring the breakthrough curves for the systems. experiments were carried out at various initial mb concentrations (co) 5, 10, 20 ppm, flow rate (u) 0.016, 0.019, 0.022 m\s, particle size 1.18-2, 2-3.35, 3.35-4 mm and mass of peanut hulls 25, 40, 60, 80 g. also a set of experiments were carried out to study the effect of chemical modification on the capacity of adsorption at conditions. the schematic representation of experimental equipment is shown in figure 1. fig. 1: the experimental unit of inverse fluidized bed results and discussion a. batch experiments adsorption isotherm studies were performed to obtain equilibrium isotherm curves and data required for the design and operation of inverse fluidized bed. the adsorption isotherm curves were obtained by plotting the weight of the solute adsorbed per unit weight of the adsorbent (qe) against the equilibrium of mb on pnh at 25 ˚c. the obtained data was correlated with linear form of langmuir and freundlich models. these models can be described in eq. 1 and eq. 2, respectively. [18]: ce/qe = (1/qmax.b) +(ce/qmax ) …(1) where: ce is the equilibrium concentration of adsorbate (mg/ l) qe is the amount adsorbed at equilibrium per gram adsorbent (mg/ g) qmax is the maximum adsorption (mg/g) and b (l/mg) is the langmuir constant related to the adsorption capacity and energy of adsorption, respectively [19]. log qe = log kf +(1/n) log ce …(2) study the performance of low cost material (peanut hulls) for dye adsorption using inverse fluidized bed 18 ijcpe vol.15 no.2 (june 2014) -available online at: www.iasj.net where: qe is the amount of adsorbate adsorbed per unit weight (mg/g of adsorbent) ce is the equilibrium concentration of the adsorbate (mg/ l) kf and n are the freundlich constants; n gives an indication of how favorable the adsorption process is. the parameters for each model were obtained from linear form of the equation to the experimental data, which can be represented in figures 2 and 3, respectively. all the parameters with their correlation coefficients are summarized in table 2. it was found that the correlation coefficient value was higher for freundlich than langmuir. this indicates that the freundlich isotherm is clearly the best fitting isotherm to the experimental data. fig. 2: langmuir isotherm for the adsorption of mb using pnh fig. 3: freundlich isotherm for the adsorption of mb using pnh table 2: isotherm parameters for mb adsorption onto pnh with the correlation coefficient model parameters values langmuir eq. 1 qmax 61.7 b 0.036 correlation coefficient(r 2 ) 0.969 freundlich eq. 2 kf 1.49 1/n 0.608 n 1.644 correlation coefficient(r 2 ) 0.988 b. inverse fluidized bed experiments 1hydrodynamic characteristics of inverse fluidized bed pressure drop, minimum fluidized velocity and bed expansion are the most important hydrodynamic characteristics of inverse fluidized bed. the determination of pressure drop in fluidized bed is a very important parameter for the efficient and economical operation of the column, since it facilitates determining friction factor; i.e. energy loss and conditions of stable flow regimes of inverse fluidized bed for the given operation. the hydrodynamic characteristics of inverse fluidized beds of adsorbent particles are represented by the fluidized bed pressure drop that can be measured either experimentally by utube monometer connected to the qvf or by equating the pressure drop across the bed to the buoyancy force of displaced fluid, allowing for the weight of the bed [20], we get the following equation: p = (ρ-ρp) (1-ε) (lb) g …(3) where: ε =void fraction of the bed, given by: ε=1-[(mp/ρp) / (/4d²lb)] …(4) where: mp = mass of adsorbent d = inside diameter of column najwa saber majeed and shaimaa abood alwan -available online at: www.iasj.net ijcpe vol.15 no.2 (june 2014) 19 2the density and the external porosity of the pnh particles the value of the granule density can be calculated from the experimental data by using a force balance. the forces acting on the fluidized granules are the buoyancy force (fb), the gravity force (fg) and the drag force (fd). the buoyancy and gravity forces are: fb=ρlvpg and fg=ρpvp …(5) where vp is the total volume of particles fluidized in the column. the drag force applied on the particles during fluidization (assuming negligible wall effects) is given by the experimental pressure drop (δpexp) multiplied by the cross sectional area of the fluidization column (a) fd=δpexpa …(6) a force balance on the particle gives: fb=fg+fd=ρpvpg+δpexpa=ρvpg …(7) since mp=ρpvp, eq. 7 can be written as: vp=(δpexpa+mpg)/ρlg …(8) and the granule density of the particles is given by ρp = mp/vp with vp obtained from eq. 8. the void volume can be found by subtracting the volume of the particles (vp) from the total volume of the fluidized bed (vb). hence, the void fraction of the fluidized bed is: ε= vε/vb …(9) since vε= (vb−vp), then eq. 9 can be written as: ε=1−(vp/vb)=1−(mp/ρpvb)=1−(mp/ρpa lb) …(10) eq. 8 is of the particular significance since it can be used to calculate the particle density if the pressures drop measurement is reliable. it can also be used to predict the pressure drop across the fluidized bed if the particles density is known [21]. 3mathematical models of bed expansion the richardson–zaki (r–z) correlation [22] is among the most useful methods to describe the relationship between the void fraction and superficial velocity in a conventional liquid fluidized bed. the r–z equation is: ε z =u/ui …(11) where u is the superficial velocity and ui is the settling velocity of a particle at infinite dilution. the r–z exponent or index (z) is a function of the particle terminal reynolds number (ret). z= 4.45 ret -0.1 for 200<ret<500 …(12) where: ret=utρdp/μ …(13) where: ρ is the density of the fluid dp is the diameter of solid particles  is the viscosity of the fluid the settling velocity at infinite dilution (ui) and the terminal velocity (ut) are related by: log(ui)=log(ut)−dp/d …(14) the r–z exponent (z) can also be obtained from the experimental data by plotting the logarithm of the superficial velocity against the logarithm of the void fraction lnu=zln(ε)+lnui …(15) there are very few correlations for an inverse fluidized bed, though several study the performance of low cost material (peanut hulls) for dye adsorption using inverse fluidized bed 20 ijcpe vol.15 no.2 (june 2014) -available online at: www.iasj.net models are available for correlating bed expansion with fluid superficial velocity in a conventional liquid–solid fluidized bed (such as the r–z model above). fan et al. [23] proposed a model based on a drag force function (f) which can be used to describe the bed expansion in an inverse fluidized bed. this correlation is expressed in terms of the void fraction of the inverse fluidized bed (ε). archimedes number ar=d 3 p (ρ−ρp) ρg/μ 2 …(16) reynolds number rep=uρdp/μ …(17) and the ratio of the particle size to the bed diameter is: f=3.21ε −4.05 ar −0.07 exp(3.5dp/d) …(18) in this model, a drag force function "f" defined as the ratio of the drag force of fluid on particles in a multiparticle system to that in a single particle system is a function of the archimedes number and the reynolds number. this drag force function for the inverse fluidization system taken from fan et al. [23] is: f=ar/13.9re 1.4 for 2 < re < 500 …(19) f=3ar/re 2 for re > 500 …(20) where the archimedes number and the reynolds number at different flow superficial velocities can be calculated from the experimental data. the void fraction of the inverse fluidized bed (ε) at different flow superficial velocities can be calculated from eq. 15.with simplification of the equation suggested by wen and ya [24], a more generalized form can be found to find the minimum fluidized bed: remf=√ -33.7 for 0.4 < re < 500 …(21) where: remf=umfρdp/μ …(22) where remf is reynolds no. at u=umf where umf is the minimum fluidized bed eq. 21 should be applicable to inverse fluidization as well assuming that the drag force of the fluid moving with superficial velocity (umf) is equal to the bouancy force which is less than the weight of the particles as described by karamanev et al., [25]. the experimental data for hydrodynamics studied can be shown in figures 4, 5 and 6. fig. 4: inverse fluidized bed pressure drop vs. superficial fluid velocity of small pnh particles size = 1.18-2 mm, mass = 0.06 kg fig. 5: inverse fluidized bed pressure drop vs. superficial fluid velocity of intermediate pnh particles size =2-3.35 mm, masses =0.025 and 0.06 kg najwa saber majeed and shaimaa abood alwan -available online at: www.iasj.net ijcpe vol.15 no.2 (june 2014) 21 the experimental results were used to find the percentage error of minimum fluidized bed, the particles density and the initial void fraction (porosity) of the fluidized bed, (all the results are represented in table 3 and table 4). the results show that the minimum fluidized velocity increased with increasing the particles size; the porosity increased with decreasing the particles size. fig. 6: inverse fluidized bed pressure drop vs. superficial fluid velocity of large pnh particles size =3.35-4 mm, mass =0.04 kg table 3: comparison of the experimental and theoretical minimum fluidization velocities error (%) umf (eq. 22;m/s) remf ar dp(mm) umf (exp.; m/s) particles size(mm) 22 0.007 11.59 22450.5 1.59 0.009 1.18 – 2 2 0.0163 43.7 119291 2.65 0.016 2 3.35 12 0.021 87.9 334774.9 3.67 0.024 3.35 – 4 table 4: calculation of the particles density and the initial void fraction from experimental data void fraction (o) bulk density (kg/m 3 ) initial bed height (m) p (estim.; kg/m 3 ) particles volume (m 3 ) p (pa) mass (kg) particles size (mm) 0.52 214.2 0.145 428.5 1.40e-04 392.4 0.06 1.18-2 0.5 178.5 0.07 362.3 0.69e-04 215.18 0.025 2-3.35 0.51 200 0.11 380.9 1.05e-04 318.8 0.04 0.51 200 0.16 387 1.55e-04 416.9 0.06 0.48 160 0.135 307 1.31e-04 441.6 0.04 3.35-4 4factors effect on mb removal 1. effect of initial concentration the effect of varying mb initial concentration was investigated; it is clear from the breakthrough curves presented in figure 7. an increase in the initial concentration made the breakthrough curves much steepe, which would be anticipated with the basis of the increase in driving force for mass transfer with an increase in the concentration of solute in solution. the breakpoint was inversely related to the initial concentration; i.e. the time required to reach saturation decreased with increasing the inlet solute concentration. also this might be explained by the fact that since the rate of diffusion was controlled by the concentration gradient, it took a longer contact time to reach saturation for the case of low value of initial solute concentration. the same conclusion was obtained by quek and al-duri [26]. fig. 7: experimental breakthrough curves for adsorption of mb onto pnh at different initial concentration (5, 10, 20) mg/l, mass of pnh = 0.04 kg, velocity= 0.016 m/s, particle size =23.35 mm study the performance of low cost material (peanut hulls) for dye adsorption using inverse fluidized bed 22 ijcpe vol.15 no.2 (june 2014) -available online at: www.iasj.net 2. effect of particle size the effect of changing particle size was also examined. the experimental results showed that fine particle sizes gave a higher mb removal than coarse particle sizes as illustrated in figure 8. this was due to larger surface area available for fine particles allowing more dye molecules to be bound per gram of fine particles; similar results of particle size effect were reported by erdem et al. [27]. fig. 8: experimental breakthrough curves for adsorption of mb onto pnh at different particle size (1.18-2 and 3.35-4) mm, concentration =10 mg/l, mass of pnh =0.04 kg, velocity =0.016 m/s 3. effect of flow rate in the design of inverse fluidized bed column, the porosity of the bed is the most significant variable and therefore, the bed depth and the flow rate are the major design parameter [17]. the effect of varying the volumetric flow rate was investigated. the experimental results in figure 9 show that with increasing the velocity from 0.016 to 0.019 m/s, the percentage dye removal will increase from 0.49 to 0.6% respectively at time (600 s), while increasing the flow rate to 0.027, the percentage dye removal will decrease to 0.35% at time (600 s) also. these results can be expressed as at the um, the porosity is not high, but with increasing the flow, the porosity will increase and then the surface area will increase also. but for higher flow rate, the residence time will be more effective than the porosity; thus the dye removal will decrease. similar result was found by bendict et al. [21]. fig. 9: experimental breakthrough curves for adsorption of mb onto pnh at different superficial fluid velocity 4. effect of mass of adsorbent the effect of adsorbent quantity on dye removal at constant flow rate, mb concentration and the same size of pnh particles is investigated and illustrated in fig. 10. the breakthrough curves shows that increasing the mass of pnh will increase the breakthrough time and the residence time. similar results have been reported for the adsorption of mb on indian rosewood sawdust [28]. fig. 10: experimental breakthrough curves for adsorption of mb onto pnh at different weights (0.025, 0.06, 0.08) kg, concentration =10 mg/l, velocity=0.016 m/s, size = 23.35mm najwa saber majeed and shaimaa abood alwan -available online at: www.iasj.net ijcpe vol.15 no.2 (june 2014) 23 5. effect of chemical modification on pnh adsorption three experiments were repeated to study the effect of chemical modification on the adsorption capacity of pnh; the results were illustrated in figures 11and12. these two figures show that the chemical modification of pnh increases the adsorption capacity of the particles. that was done by two mechanicals: first by increasing the acidity of adsorption sites (hydroxyl group) and second by increasing the surface area due to erosion by nitric acid. the same conclusion was obtained by thomas et al. [29]. fig. 11: comparison between modified and unmodified pnh particles for mb adsorption, concentration =10 mg/l, mass of pnh =0.04 kg, velocity =0.016 m/s, size=2-3.35 mm fig. 12: comparison between modified and unmodified pnh particles for mb adsorption, concentration= 10 mg/l, mass of pnh =0.04 kg, velocity = 0.016 m/s, size = 1.182 mm conclusions  the percentage of dye removed increased from (70.5%) to (99.7%) with increasing adsorbent dosage from (2 g) to (16 g) and increased with increasing contact time.  the results showed that the (freundlich) model gave the best fitting for adsorption capacity; i.e. higher value of r 2 (0.988).  inverse fluidized bed set of experiments were studied to find the optimum conditions of adsorption and found that the optimum concentration was (5 mg/l), the optimum particle size was 1.18-2 mm size, the optimum mass of pnh was (0.08 kg) and the optimum superficial fluid velocity was (0.019 m/s).  in inverse fluidized bed experiments, the percentage removal increase by increasing contact time and adsorbent surface area. the result showed the chemical modification of pnh by nitric acid gave greater dye removal; i.e. from (65%) to (84%) and from (80%) to (88%) respectively for the last two experiments nomenclatures mb methylene blue pnh peanut hulls references 1alwan sh. a., msc.thesis,"study the performance of low cost material(peanut hulls) for dye adsorption using inverse fluidized bed"university of baghdad ,iraq, january,2013. 2ray p.k., 1986, “environmental pollution and cancer”, journal sciences industrial resource, vol. 45, pp 370 – 371. 3mackay, d.m., roberts, p.v., 1984, “the dependence of char and carbon yield on lignocellulosic study the performance of low cost material (peanut hulls) for dye adsorption using inverse fluidized bed 24 ijcpe vol.15 no.2 (june 2014) -available online at: www.iasj.net precursor composition”, carbon, vol. 20, 95. 4el-geundi, m.s., 1990, "adsorption equilibria of basic dyestuffs onto maize cob", ads. sciand tech., (7), pp 114-123. 5el-geundi m.s., 1991, "colour removal from textile effluents by adsorption techniques", water resources, vol. 25 (3), pp 271273. 6laila b. k., 1996, “adsorption characteristics of activated carbon obtained from rice husks by treatment with phosphoric acid”, ads. sci. and tec. vol 12(3), pp 317 325. 7gargova k., eser s., 1997, “effects of activation method on the pore structure of activated carbon from apricot stones”. carbon vol. 34, pp 157-160. 8namaisvayam c. and kadirvelu k.,1997, "activated carbons prepared from coir pith by physical and chemical activation methods", bioresource technology, vol. 62, pp. 123-127 9mackay, g., m.s. otterburn and j.a. aga. 1987." pore diffusion and external mass transport during dye adsorption on to fuller's earth and silica." j. chern. tech. bio tech. 37: 247-256. 10namasivayam, c. and r.t. yamuna. 1992a. "removal of congo red from aqueous solutions by biogas waste slurry." j chern. tech. bio tech. 53: (in press). 11namasivayam, c. and b. chandrasekaran. 1990. "studies on the treatment of wastewaters from dyeing industries using fe (iii)/cr (iii) sludge and red mud." j. ind. assoc. environ. manage1nent conference issue (in press). 12gupta, g.s., g. prasad and v.n. singh. 1989." china clay as adsorbent for mordent blue13." j. ind. assoc. environ. manage1nent. 16: 174. 13nawar, s.s. and h.s. doma. 1989. "removal of dyes from effluents using low-cost agricultural by products."sci. total envt. 79: 271. 14low, ks. and c.k lee. 1990. "the removal of cationic dyes using coconut husk as an adsorbent." pe1tanika 13: 221-228. 15khare, s.k., kkppanday, r.m. srivastava and v. singh. 1987. "removal of victoria blue from aqueous solution by fly ash." j. che1n. tech. bio tech. 38: 99-104. 16macky, g. ramprasad, g., and mowli, p.f., 1996, “equilibrium studies for the adsorption of dyestuffs from aqueous solutions by low-cost materials”, water, air and soil pollution, vol. 29, pp. 273 -283. 17bajrang l. b., 2011," hydrodynamics of inverse liquid fluidized bed", ph. d. thesis, national institute of technology, rourkela, (internet document). 18weber, j.r., and walter, j., 1972, "physicochemical processes for water quality control", wiley – interscience, new york, (internet document). 19koffi l., adouby k., wandan e., yao b. and kotchi k., 2010, “ sorption and desorption of pb(ii) from equeous solution using triplochiton scleroxylon sawdustas sorbent”, j. applllied sci., 10 , pp 317323. 20mccabe w .l.,smith j.c.,harriot p.,2001."unit operation of chemical engineering",mcgraw hill international,singapore,pp171-180. 21bendict r.j., kumaresan f. g., velan m., 1998, "bed expansion and pressure drop studies in a liquid-solid inverse fluidized bed reactor", bioprocess and biosystems engineering, 19(2), pp 137-142. najwa saber majeed and shaimaa abood alwan -available online at: www.iasj.net ijcpe vol.15 no.2 (june 2014) 25 22richardson j.f., zaki w.n., 1954, "sedimentation and fluidization", part i, trans. instn. chem. eng. 32, pp 35–53. 23fan l. s., muroyama k., chern s.h., 1982, "hydrodynamic characteristics of inverse fluidization in liquid–solid and gas–liquid–solid systems", chemical engineering journal, 24, pp 143–150. 24wen c.y., yu y.h., 1966, “a generalized method for predicting the minimum fluidization velocity”, american institute of chemical engineering journal, 12, pp 610-612. 25karamanev d., nikolov l., 1992," bed expansion of liquidsolid inverse –fluidization", aiche journal, 38, pp 1916-1922. 26quek, s. y. and al-duri, b., 2007, "application of film-pore diffusion model for the adsorption of metal ions on coir in a fixedbed column", chemical engineering and processing, v.46, pp 477-485. 27erdem e.a., karapinar n.b., donat r., 2004, "the removal of heavy metal cations by natural zeolites", journal of colloid and interface science 280, pp 309–314. 28garg vk., amita m., kumar r., gupta r., 2004, "basic dye (methylene blue) removal from simulated wastewater by adsorption using indian rosewood sawdust – a timber industry waste". dyes and pigments 63, pp 243–250. 29thomas j. k., william r. w., janet h. w., ronald b., 1986,"chemical composition and in-vitro digestibility of thermochemically treated peanut hulls", j. sci. food agric.,37, pp 632-636 iraqi journal of chemical and petroleum engineering vol.15 no.2 (june 2014) 4959 issn: 1997-4884 experimental determination of the elastic and viscous behavior of polycarbonate melts at different temperatures and their relationship to the steady state viscosity via the cox-merz rule shatha k. muallah bio-chemical engineering department, al-khwarizmi engineering college, university of baghdad abstract rheological instrument is one of the basic analytical measurements for diagnosing the properties of polymers fluids to be used in any industry. in this research polycarbonate was chosen because of its importance in many areas and possesses several distinct properties. two kinds of rheometers devices were used at different range of temperatures from 220 ˚c-300 ˚c to characterize the rheological technique of melted polycarbonate (makrolon 2805) by a combination of different investigating techniques. we compared the results of the linear (oscillatory) method with the non-linear (steadystate) method; the former method provided the storage and the loss modulus of melted polycarbonate, and presented the cox-merz model as well. one of the major problems in measuring the viscosity of polycarbonate at high shear rates, especially at the extremes of temperatures, was that during the use of the capillary rheometer, long molecule chains led to high viscosity. keywords: rheology, rheology dynamic property, cox-merz rule, complex modulus, polycarbonate polymer melt, thermo-rheological modeling, oscillatory measurements, rotational rheometer, high-pressure capillary rheometer. introduction polycarbonate (pc) makrolon®, one of the important polymers, is used in many areas due to having a lot of good specifications. the generic name for polyester contains the repeating carbonate group. there is a wide spectrum of polycarbonates, especially from phenol. figure1 shows the structure of the repeating unit of polycarbonate [1]. fig. 1:the stracture of polycarbonate molecule polymers fit into a broad class of complex fluid and are characterized by the term non-newtonian phenomena, e.g. high viscoelastic behavior, because of their ability to vigorously determine both the elastic and viscous response of a sample in one experiment [2]. techniques for measuring rheological properties especially flow properties were well covered by many scientists [3]. most rheological studies for polymers concentrated on the viscosity function and dynamic viscoelastic properties, which can be measured continuously as the material undergoes iraqi journal of chemical and petroleum engineering university of baghdad college of engineering experimental determination of the elastic and viscous behav ior of polycarbonate melts at different temperatures and their relationship to the steady state viscosity via the cox -merz rule 50 ijcpe vol.15 no.2 (june 2014) -available online at: www.iasj.net temperature-induced changes from solid to liquid and vice versa because both molten and solid states are extremely important to sectors of plastics industry [2]. the main advantages of polycarbonate are transparency, dimensional stability, flame resistance, high heat distortion temperature, and it is a transparent amorphous polymer which exhibits outstanding physical properties such as impact resistance (almost unbreakable), heat resistance up to 125˚c and excellent clarity [4]. for this reason, polycarbonate is often used to replace glass or metal in demanding applications. therefore, it is an important and widely used engineering thermoplastic. however, pc exhibits high notch sensitivity, and it is susceptible to crazing or cracking on exposure to various solvents. to clarify the viscoelastic properties of pc melt, we know that the rheology offers three different measurements methods, steady state, small amplitude oscillatory shear (saos) and elongation flow [5]. oscillation technique (dynamic rheological testing) is a popular deformation mode for investigating linear viscoelastic behavior [6]. it may be used to determine the strength and stability of a material, and it gives clear indication of the behavior of the sample, whether viscous or elastically dominated over a given frequency range. it applies a sinusoidal stress or strain at changing frequency ω; the induced response must follow a sine wave [7], which is performed on common rheometer, as well as it gives rise to modulus g', in phase with the deformation, and another part g″, out phase. these two moduli are therefore called the elastic modulus g' and the loss or viscose modulus g" because the latter is related to viscous dissipation of the fluid. the angle δ contains this deformation through the ratio of the loss modulus to the storage modulus: tan δ =g″/g' …(1) and it represents the damping properties of the sample [8, 9]. the well-known relationship of coxmerz has long been used to advantage in relating the complex viscosity measured in linear oscillatory testing to the steady shear viscosity as a function of shear rate [10, 11] .the cox-merz rule is an empirical correlation that has been confirmed experimentally for several synthetic polymers. the superimposition of the shear rate dependence of steady shear viscosity, that is η ( ̇), and of frequency dependence of the complex viscosity, that is η*(ω); equal values of frequency and shear rate were first reported by cox-merz (1958): η*(ω) = η (ω) |ω= ̇when ω= ̇ [12]…(2) the objectives of this research were to investigate thermal rheological of shear viscosity of pc (makrolon) in a temperatures region of 220 ˚c -300 ˚c and a shear rate of 0.001 1s to 1000 1s ; to compare the steady viscosity η to the dynamic η* by applying cox-merz rule values of g, g″ were obtained by using capillary rheometer with high shear rate and compared with cox-merz rule. experimental work all the measurements reported were carried out on two kinds of rheometer devices as shown in the figures 2-4 to determine the melt behavior of granular polycarbonate; the type of polycarbonate used is makrolon®2805 of the material science bayer company. the samples were pre dried at 120 ˚c before analysis for 12 hours http://www.omnexus.com/tc/polycarbonate/index.aspx?id=impact-strength http://www.omnexus.com/tc/polycarbonate/index.aspx?id=thermal-resistance http://www.omnexus.com/tc/polycarbonate/index.aspx?id=glass-solution http://www.omnexus.com/tc/polycarbonate/index.aspx?id=metal-solution shatha k. muallah -available online at: www.iasj.net ijcpe vol.15 no.2 (june 2014) 51 to make sure the arrival of humidity is not more than 0.02% residual moisture; that pc may be adversely affected by water at high melt temperature of greater than 250˚c. therefore, vigorous drying was important for good reproducibility. the dryer used was toro-systems dry-jet mini made by (gfk) company. rheological measurements were performed with the rotational rheometer (ar-g2), by using the plate-plate geometry as shown in figure 2 and figure 3 (a). thus parallel plates are usually preferred for measuring viscoelastic material functions [13]. steady viscosities were obtained at different shear rates between 0.0001 s -1 and 1 s -1 as shown in figures 5 and 6. oscillatory mode was used for rheological measurements using the same rheometer above. the dynamic properties i.e. storage modulus, g' [pa], loss modulus g" [pa] and phase angle δ as a function of angular frequency ω [rad/s] were measured as show in figures 7 and 8. the frequency of oscillation was varied from 0.01 to 1000 rad/s. the rheological characteristics were measured at different rate of temperatures from 220-300 ˚c. all tests were conducted under the presence of nitrogen gas to prevent oxidation of the samples. to study the large-scale deformation and flow characteristics of pc by applying the cox-merz model, the range of shear rate measurements can be extended from low shear rate to high shear rate as shown in figures 6 and7. the other device that was used for the comparison between the values of the shear rate is capillary rheometer (rg20 – göttfert) shown in figure 4. capillary rheometer is used primarily to determine the viscosity at high shear rates from10 to 1000 s -1 . all tests were performed in replicate to ensure representative sampling. in case of the high shear rates of viscosity measurements, the use of the high-pressure capillary rheometer is important. figures 5and 6 show the principle of the measurements. the fluid is pressed with a pistoncylinder system through a capillary tube. fig. 2: ar-g2 (ta-instruments) rotational rheometer with the used plate-plate geometry fig. 3: (a) plate-plate (b) coneplate system experimental determination of the elastic and viscous behav ior of polycarbonate melts at different temperatures and their relationship to the steady state viscosity via the cox -merz rule 52 ijcpe vol.15 no.2 (june 2014) -available online at: www.iasj.net fig. 4: rheograph 20 (rg20 göttfert) highpressure capillary rheometer fig. 5: measurements of the shear viscosity of polycarbonate at a temperature region of 220 ˚c to 280 ˚c for steady state, cox-merz and capillary shatha k. muallah -available online at: www.iasj.net ijcpe vol.15 no.2 (june 2014) 53 fig. 6: measurements of the shear viscosity of polycarbonate at a temperature 300 ˚c for steady state and cox-merz fig. 7: srorage and loss modulus for a wide range of frequency, from 220 ˚c to 330 ˚c experimental determination of the elastic and viscous behav ior of polycarbonate melts at different temperatures and their relationship to the steady state viscosity via the cox -merz rule 54 ijcpe vol.15 no.2 (june 2014) -available online at: www.iasj.net fig. 8: srorage and loss modulus for a wide range of frequency, from 220 ˚c to 300 ˚c theory and the relationship between the parameters the theoretical measurements of the shear rate and viscosity for rotational rheometer is obtained from the given angle movement velocity ω with h r  …(3) and the measured moment m with the shear stress and the given shear viscosity can be calculated with [15]     3 2 r m  …(4) in case of capillary rheometer, the difference of the pressure p between inlet and outlet of the tube is measured in connection with the volume flux v . these quantities are used to calculate two new variables, a weighted flow rate and the wall shear stress v d q  3 32   …(5) l dp w 4   …(6) the correlation between the flow rate and the wall shear rate under stationary condition in a tube results from the balance of momentum and reads   w dq w    0 24  …(7) integration by parts leads to the real shear rate at the wall q d qdd w w              )(log )(log 3 4 1 2    …(8) afterwards the shear viscosity is calculated by w w      …(9) this relation is called rabinowitschweissenberg-correction [15]. the most accurate characterization of viscoelastic behavior is achieved with dynamic mechanical analysis [16]. sinusoidal or (oscillatory) rheometry is often commonly used to characterize the frequency dependence of polymer melts. the mathematical application of the oscillatory test is as follows: γ=γ₀sinωt …(10) σ=σ₀sin(ωt+δ) …(11) equation 10 represents the strain function, where γ and γ₀ in[s -1 ] are the strain and the strain amplitude respectively, ω is the angular frequency which is equal to 2πf and f is the frequency. it need to be mentioned that all rheological measurements used ω in [rad/s]. equation 11 represents the stress function, where σ and σ₀ are the stress and the stress amplitude respectively, and δ is the angle which the resultant stress will be delayed time by the phase angle δ [20]. figure 9 shows the sinusoidal of two waves of frequency shatha k. muallah -available online at: www.iasj.net ijcpe vol.15 no.2 (june 2014) 55 ω, with one in phase with the strain and one 90⁰out-of-phase; equation 12 clarifie this state: σ=σ′+σ"=σ"₀sinωt+σ₀"cosωt …(12) where σ' and σ" represent the stress that consists of in-phase and out-phase, respectively. from the relationship between stress and strain, the dynamic moduli g′ and g″ can be defined: g′= ₀ ۬ ₀ is called elastic or in-phase modulus …(13) g″= ₀ ۬ ₀ is called viscous, loss, or out-phase modulus …(14) by using the maxwell model, a first order linear differential equation with a solution gives the shear stress as in equation 15: σ=(ωτcosωt-sinωt) …(15) if the part of the stress in-phase is applied by putting sin [ωτ] =0, g' is written as: g′= …(16) and if the stress out –phase, by setting cosωτ=0, g″is written as: g″= …(17) where τ in equations 15, 16 and 17 is so-called relaxation time (s). to compute the shear rate ̇, by the derivative of the strain in equation3, this leads to the dynamic viscosity η. ̇= =γ₀ωcosωt …(18) we know the viscosity is a function of the ratio of the stress to the shear rate as shown in the following relationship which can be obtained [17]: η′= ₀ ̇₀ ₀ …(19) η″= ₀ ̇₀ = ₀ …(20) where η′ is dynamic viscosity, η″ is related to the dynamic rigidity through g′. the overall magnitude of the complex viscosity and complex modulus are defined as in equation 21 [6, 7]: |η*|= (η′²+ η″²) ½ = [( ) ²+ ( ) ²] = …(21) tanδ = = is called the loss factor, or the relation between the viscoelastic moduli; i.e. the ratio between viscous and elastic η*, g* can be defined in oscillatory test as shown in the following equations: η*=η'+iη″ …(22) g*=g'+ig″ ...(23) where i=√ to extend the shear rate measurements from very low shear rate to high shear rate, cox-merz rule can be applied. the empirical cox-merz rule created a link between linear and nonlinear quantities from amplitude oscillatory shear experiments as in the following equations [10, 18]: |η*(ω)|=[η′²(ω)+η″²(ω)] ½= η( ̇)| ̇ …(24) we can repeat equation 20: |η*(ω)|=[η′²(ω)+ )²] ½ …(25) experimental determination of the elastic and viscous behav ior of polycarbonate melts at different temperatures and their relationship to the steady state viscosity via the cox -merz rule 56 ijcpe vol.15 no.2 (june 2014) -available online at: www.iasj.net fig. 9: sinusoidal forms of stress and strain for a viscoelastic substance modeling approaches in order to reach a possible analytical approach for the experimental data, carreauyasuda model (as explained by equation 26) was adapted to model the shear thinning behavior for the proposed polymer in this work. ) ) ( ) ) …(26) where λ is the time constant to start the non-linear region in (s), n and m which are dimensionless exponents to adjust the transition of the viscosity into the non-linear. as shown in figure 10 and table 1, the modeling approaches for isothermal and nonisothermal processes can be used to provide a close representation of the measurements. table 1: parameters of the carreau-yasuda model obtained for each temperature step temperature ˚c λ n m η₀ 220 240 260 280 300 0.1 0.05 0.014 0.01 0.006 0.8 0.82 0.7 0.6 0.4 0.6 0.4 0.6 0.6 0.55 16350 4520 1956 921.4 497.8 fig. 10: averaged experimental results (symbols) and fitted lines with the carreau model on each temperature discussion and conclusion the steady and dynamic state of viscosity for melt polycarbonate (makrolon 2805) is plotted in the figures 7 and 8. the stationary shear flow in polymer melt is so important to characterize the rheological technique by using rotational rheometer. to quantify the visco-elastic flow behavior of polymer solutions, all shatha k. muallah -available online at: www.iasj.net ijcpe vol.15 no.2 (june 2014) 57 measurements were accomplished in a nitrogen atmosphere in order to avoid oxidation processes of the polymer molecules, using 10 l/min volumetric flow rate of nitrogen. moreover, all the temperatures were used except the high temperature (280, 300 ˚c) and were matched with cox-merz rule; we see that the dynamic viscosity is consistently higher than its steady state equivalent as we move away from zero frequency, where they tend to coincide as shown in figures 5 and 6. in addition, the capillary rheometer was carried out at high shear rate and was compared with the cox-merz rule. only at 220 and 240 ˚c, it matched with cox-merz. other temperatures approximated conformity except the temperature 300 ˚c. at 300 ˚c, a problem was observed in shear rate measurement using capillary rheometer, due to the long molecule chains and that led to high viscosity and pressure linearly. supposing that we are another possible nozzle for this kind of polymer at high temperatures. in fact this type is not available in the lab. the modeling approaches for the processes can be used to provide a close representation of the measurements. in fact, it is possible to use the carreau-yasuda model for isothermal and non-isothermal processes. oscillatory experiments have to be accomplished according to the rheological circle [16] (see figure 11). the elastic components of a polymer solution can then directly be correlated with the storage modulus g', whereas the viscous components are represented by the loss modulus g". furthermore, this device was used to introduce the dynamic oscillatory shear flow which described the response to small amplitude deformation with different temperatures to quantify the viscoelastic flow in addition to its mission to comply with the steady state measurements to extend the shear rate. in oscillatory measurement shown in figures 7 and 8, we noted that g" is greater than g' in all temperatures used. this means the energy used to deform the material is dissipated viscously and the material behavior is liquid like, and indicates that the viscous component of the modulus is dominant over the elastic counter. but at high angular frequency, g' is greater than g". this phenomenon for a flow behavior of polycarbonate shows which is radically different from many typical polymer. furthermore, the high frequency limit is about 628; the maximum is achieved by using the rotational rheometer (ar-g2). so we can only get values equal to g'with g" in the temperatures 220 and 240 ˚c but at elevated temperatures it is not enough to enter the plateau regime of the storage modulus. this means that the network parameters are not accessible for each temperature without extrapolation as shown in table 2 and figure 12 to designate the value of the angular frequency. fig. 11: rheological cycle [16] table 2: the angular frequency at different temperatures with the same values of g`and g`` temp. ˚c ω (rad/s) g`=g″ 220 110.161 438269.777 240 506.304 504105.202 260 876.436 643405.797 280 1057.002 703756.66 300 3193.39 869615.603 experimental determination of the elastic and viscous behav ior of polycarbonate melts at different temperatures and their relationship to the steady state viscosity via the cox -merz rule 58 ijcpe vol.15 no.2 (june 2014) -available online at: www.iasj.net fig. 12: the angular frequency at different temperatures with the same values of g`and g`` list of symbols w , shear rate (s -1 ) r the radius of the plate-plate geometry and the sample (m)  angle velocity of the plateplate geometry (radius/s) h height of the sample (m)   , η ' ,η " , η * viscosity and the viscosity function (pas) dynamic viscosity (pas),dynamic rigidity(pas) (pa) complex viscosity(pas) m measured moment (nm) q weighted flow rate (s -1 ) v flow rate (volume flux) (m 3 /s) d diameter of the tube of the capillary rheometer (m) w , shear stress and wall shear stress (n/m 2 ) p pressure gradient (bar) l length of the tube of the capillaryry rheometer (m) σ,σ₀ stress and stress amplitude (n/m 2 ) σ′,σ" stress of in-phase and outphase (n/m 2 ) g',g″ g* elastic and viscous modulus (pa) complex modulus (pa) references 1gert.f.bumann, smual steingiser "rheological measurement on polycarbonate", journal of polymer science,vol 1, pp.3395-3406, 1963. 2bird, r. b., armstrong, r. c., and hassager, o., "dynamics of polymeric liquids: fluid mechanics", journal of polymer science, vol 1, pp.100-101, 1977. 3m.a.rao,"rheology of fluid and semisolid food principle and applications", food engineering series, isbn_13:978_0_387_70929_1, 2007. 4m. rahail parvaiz1, p. a. mahanwar2, smita mohanty1 and sanjay k. nayak morphology, "mechanical,thermal electrical and rheological properties of polycarbonate composites reinforced with surface modified mica", journal of minerals and meterials characterization, vol 9 (11), pp.985-996, 2011. 5jan philip plog, "investigation of visco_elastic behavior of water soluble cellulosic derivatives in uniaxial elongation", a doctor degree, the dep. of chemistry, the university of hamburg, germany, 2005. 6k.walters, h.a.barnes, j.f.hutton, "rheology series (an introduction to rheology)", university of wales, u.k., 1993. 7johanna.aho,"rheological characterization of polymer melts in shear and extension: measurement reliability and data for practical processing", thesis for the degree of doctor of science in tampere university of technology, finland, issn1458-8045, 2011. 8c.verdier,"rheological properties of living materials from cell to tissues", journal of theoretical medicines, vol 5 (2), pp.67-91, 2003. shatha k. muallah -available online at: www.iasj.net ijcpe vol.15 no.2 (june 2014) 59 9mills and kokini, "comparison of steady shear and dynamic viscoelastic properties of guar and karaya gums", journal of food science, vol. 49, pp.1-4, 1984. 10cox-merz "correlation of dynamic and steady flow viscosities", journal polymer sci, vol.28, pp.619-622, 1958. 11t.s.al-hadithi, k.waters, h.a.barnes "the relationship between the linear (oscillatory) and nonlinear (steady-state) flow properties and colloidal systems", colloid polym. sci., vol. 270, pp.40-46, 1992. 12david, w.mead, "analytical derivation of cox_merz rule using the mld´´toy´´model for polydisperse linear polymer", rheo acta, vol.50, pp.837-866, 2011. 13m.hasan tareque,"a study of polycarbonate/poly (butylenes tetra phthalate) compounding in a twin screw extruder", a thesis, university of waterloo, canada, 2009. 14a.al-baldawi, "modellierung und simulation viskoelastischer polymerschmelzen", isbn: 978-389958-598-8, kassel university press, 2012. 15a.al-baldawi, s.muallah., olaf ünsch 1 , "thermo-rheological investigation and modeling of the shear viscosity of polypropylene above melting temperature", journal of alkahwrizmi, iraq ,2013. 16stacey, d.reubush,"effects of storage on the linear viscoelastic response of polymer-modified asphalt at intermediate to high temperatures, master of science in civil engineering", virginia polytechnic institute, 1999. 17v.tirtaatmadja,k.c.tam,and jenkins, "superposition of oscillations on steady state flow as a technique for investigation the structure of associative polymer", macromolecules, vol. 30(5), pp.1426-1433, 1997. 18w.m.kulicka, r.s.poter,"relation between steady shear flow and dynamic rheology", issn 0035-4511, rheol.acta., vol.19, pp.601-605, 1980. 19pierre,j .carreau, "rheological equations from molecular network theories", journal of rheology, vol.16, pp.99-127, 1972. 20s.m.hosseinalipour,a.tohidi and m.shokpour ,"a review of dough rheological models used in numerical applications", journal of computational applied research in mechanical engineering, issn: 2228-7922, vol.1 ,no.2, pp.129147, 2012. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.20 no.1 (march 2019) 23 – 29 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: huda adil sabbar, email: enghudaadil@gmail.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. adsorption of phenol from aqueous solution using paper waste huda adil sabbar department of biochemical engineering, al-khwarizmi collage of engineering, university of baghdad abstract the exploitation of obsolete recyclable resources including paper waste has the advantages of saving resources and environment protection. this study has been conducted to study utilizing paper waste to adsorb phenol which is one of the harmful organic compound byproducts deposited in the environment. the influence of different agitation methods, ph of the solution (3-11), initial phenol concentration (30-120ppm), adsorbent dose (0.5-2.5 g) and contact time (30-150 min) were studied. the highest phenol removal efficiency obtained was 86% with an adsorption capacity of 5.1 mg /g at optimization conditions (ph of 9, initial phenol concentration of 30 mg/l, an adsorbent dose of 2 g and contact time of 120min and at room temperature). the well-known langmuir and freundlich adsorption models were studied. the results show that the equilibrium data fitted to the freundlich model with r 2 =0.9897 within the concentration range studied. the main objective of this study is finding the best mixing and conditions for phenol removal by adsorption via paper waste. keywords: adsorption, isotherm model, phenol, untreated waste office paper, ultrasonic wave device received on 28/11/8102, accepted on 20/01/8102, published on 30/03/8109 https://doi.org/10.31699/ijcpe.2019.1.4 1introduction phenol is critical poisons existing in wastewater as aromatic semi-volatile hydrocarbons. several industries such as rubber, textile, pharmaceutical, pulp and paper, pharmaceutical industries, plastics, coke manufacturing, ferrous industries and petroleum refineries may discharge a significant amount of phenol ‎[1]. phenol is easily absorbed into the body through skin, stomach, and lungs. further, phenol can cause conflict with the brain control of regular breathing patterns ‎[2]. thus, it is considered as hazardous pollutant since it causes adverse effects on health and the environment. according to the united states environmental protection agency (usepa), the acceptable concentration of phenol in surface water should be less than 1.0 mg/l and in drinking water should not exceed 0.002mg/l ‎[3]. in addition, the presence of phenol into drinking water sterilized by chlorine compounds results in the establishment of phenol compounds leading to serious problems to health and environment. phenol gives undesirable taste and odor to drinking water. thus, wastewater containing phenol must be treated to prevent health and environmental risks ‎[4]. phenol removal from wastewater has been carried out by various methods such as chemical oxidation ‎[5] membrane filtration ‎[6], biodegradation ‎[7], electrocoagulation ‎[8], photodegradation ‎[9], solvent extraction ‎[10] and adsorption ‎[11]. adsorption is an effective method among these technologies. it is considered as a suitable technique for phenol removal from wastewater because of its insensitivity to poisonous and toxic wastes. in addition, adsorption has the merits of flexibility, the simplicity of design, ease of operation ‎[12]. recently, researchers have been focusing on using of natural adsorbents instead of conventional adsorbents ‎[13]. likewise, they have used effective and low-cost adsorbents from different raw materials derived from waste stuff to remove phenol such as miswak’s root ‎[14], sawdust ‎[15], coal fly ash ‎[16], forest waste [10], lignitic coals ‎[17], banana peels ‎[2] and rice straw ‎[18]. a considerable amount of paper waste is daily produced and used for different purposes. and it is burned to create heat and the only amount of it is recycled for paper industries. the sorption ability of cellulosic material makes the waste paper a possible green to be used as a low-cost adsorbent for phenol removal. recently, using ultrasonication for extraction and refining processes has gained great attention. however, more information is required about the removal of organic pollutants from wastewater by adsorption coupled with ultrasonication method ‎[19]. adsorption isotherm models have been applied to explain adsorption data such as langmuir and freundlich model. the langmuir isotherm assumes that adsorption on a surface is limited to a single molecular layer with a finite number of identical sites. all site can take in only one adsorbate molecule ‎[20]. the langmuir isotherm equation is considered the first theoretically developed isotherm model and it keeps an essential location in physisorption and chemisorption theories‎[21]. https://doi.org/10.31699/ijcpe.2019.1.4 h. a. sabbar / iraqi journal of chemical and petroleum engineering 20,1 (2019) 23 – 29 42 the freundlich isotherm explains that the adsorption occurs on heterogeneous sites with non-uniform distribution of energy level, and it proposes reversible adsorption and possible adsorption on multilayers ‎[22]. 2materials and experimental work 2.1. phenol phenol is a crystalline and colorless to light pink material (phenol changes pink on exposure to light and air). phenol used in this study has been supplied by loba chemie pvt. ltd. (laboratory reagents & fine chemicals). the chemical and physical properties of phenol are shown in table 1. table 1. characteristics of phenol chemical formula c6h5oh molecular weight 94.11 g/mol solubility (5% in water) clear, colorless solution appearance white crystals or crystalline flakes stabilizer max 0.15% normal boiling point 181.84 °c 2.2. adsorbent paper waste (a4) was collected from a local office. according to the label on the package, the paper characterized as flat, smooth, multi-purpose paper, elemental chlorine free fiber, acid-free and moisture retention capacity. it was cut into small pieces (4*2 mm) by suitable paper shredder and then kept in dry place. 3phenol adsorption study the adsorption capacity of the adsorbent was studied on a laboratory scale liquid phase batch. the experiments were conducted at a fixed amount (1gm) of waste paper which was positioned into 125-ml flasks containing 20 ml phenol solution. the initial concentrations of phenol solution at rang from30 to 90 mg/l were prepared. the ph of phenol solutions during the interaction with the adsorbent was found to be ranging of (3–11). three different devices were used to agitate the solution which are the laboratory shaker, the mechanical agitator, the magnetic stirrer and ultrasonication device with an agitating speed of 250 rpm and for 15 0 min to meet the environmentally relevant conditions. the experiments were done at a temperature of 25°c. at the end of mixing time, the samples were withdrawn, filtered by filter papers to remove the suspended adsorbent and analyzed using uvvisible spectrophotometer (uv-160 a shimadzu). phenol adsorbed by paper waste was found by calculating the difference between the initial concentration (co) and the equilibrium concentration (ce). the effect of ph, phenol concentration, adsorbent dose and contact time on the phenol adsorption was studied. qe = (co ce)*v/m (1) r%= [(co-ce)/ce]*100 (2) where qe is the adsorption capacity, co represent the initial concentrations of phenol and ce equilibrium concentrations of phenol (mg/l), respectively; v represents the volume of the phenol solution (ml) and m is the mass of adsorbent (g) computer interfaced uv-visible spectrophotometer (gbc cintra 6 series v-3656) was used for samples analysis at an absorbance value of 270 nm. treated water samples of 2 ml were placed in a quartz cell and analyzed to measure phenol concentration. phenol concentration was estimated using the phenol concentration-calibration curve shown in fig. 1. the calibration curve was prepared using different known phenol concentrations. a straight line with a slop of 0.0139 was obtained to determine unknown phenol concentration remaining in the solution. then, the percentage removal of phenol was calculated by eq. (2). fig. 1. calibration curve of phenol adsorption 3.1. effect of mixing techniques to study the effect of mixing methods on the adsorption of phenol, the erlenmeyer flasks containing the adsorbent and adsorbate solution were agitated at 200 rpm for 200 min at room temperature. the adsorption experiments were carried out using 30 ml of 30 ppm phenol solution containing 1 g of paper waste and a ph of 8. 3.2. effect of ph on phenol adsorption the ph of the solution is one of the most important parameters and it plays a major role in the adsorption process. the experiment was carried out in the ph range of 3-11 adjusted by 0.3n hcl and 0.3n naoh. the adsorption experiments were executed using 30 ml of 30 ppm phenol solution containing 1 g of paper waste. the solutions were agitated for 150 min at 250 rpm at room temperature. y = 0.0139x 0 0.02 0.04 0.06 0.08 0 1 2 3 4 5 6 a b so rb a n ce concentration of phenol (ppm) h. a. sabbar / iraqi journal of chemical and petroleum engineering 20,1 (2019) 23 – 29 42 3.3. effect of phenol concentration the effect of initial phenol concentration on the equilibrium uptake was studied by differing the initial phenol concentration in the range of 30-90 ppm. the adsorption experiments were carried out using 30 ml of phenol solution containing 1 g of paper waste and solution ph 9. the solutions were agitated for 150 min at 250 rpm at room temperature. 3.4. effect of adsorbent dose to investigate the effect of adsorbent dose, different amounts of adsorbent (0.5-2,5 g) were used. the adsorption experiments were achieved using 30 ml of 30 ppm phenol solution and solution ph 9. the solutions were agitated for 150 min at 250 rpm at room temperature. in this study and adsorption capacity was determined using eq.(1). 3.5. effect of contact time on dye adsorption the effect of contact time on the phenol removal was conducted on phenol solution with an initial concentration of 30 ppm. the flasks were filled with 30 ml of the aqueous solutions of ph 9 were shaken for a contact time ranging of (30-150) min at ph 9. the best values of solution ph and a dose of waste paper were used for this study. 3.6. adsorption isotherm the adsorption isotherm is a commonly used method for representing the equilibrium states of an adsorption system. the adsorption isotherm gives information related to adsorbate and adsorbent, ‎[23]. generally, it describes using an isotherm just in what way the adsorbed molecules distribute between the liquid phase and the solid phase when the adsorption process reaches an equilibrium state ‎[24]. the experimental data were suitable to langmuir and freundlich models using eq.(3) and eq(4) respectively. qe = kf (3) qe = (4) where qe is the equilibrium amount absorbed in (mg/g)of sorbent (mg/g), kf is the freundlich adsorption coefficient (mg/g)(l/mg), ce is the equilibrium concentration (ppm), n is considered a number which describes surface heterogeneity and sorption intensity. if n is ranging between 2 and 10, this means good adsorption. if the numerical value of 1/n less than one, this indicates that adsorption capacity is only slightly suppressed at lower equilibrium concentrations. a is the maximum adsorption capacity (mg/g) and (b) is the langmuir fitting parameter (l/mg) ‎[16]. it can be expected whether an adsorption system is unfavorable or favorable according to the value of rl which is an important characteristic of the langmuir isotherm. it is a dimensionless constant referred to separation factor or equilibrium parameter and defined by (5): rl= (5) where co is the highest initial concentration, this parameter suggests the type of isotherm to be irreversible (rl = 0), favorable (0 < rl < 1) or unfavorable (rl > 1) [20] 4results and discussion 4.1. effect of mixing techniques the removal efficiency of phenol by paper waste is studied by four different ways of mixing as shown in fig. 2. it shows that mixing technique plays an important role in the proportion of removal. the ultrasonic wave device and the mechanical device showed higher efficiency for phenol removal than the laboratory shaker, and less adsorption occurred using the laboratory shaker. this can be attributed to the advantages of using ultrasound including highly effective mixing and micro-mixing, high energy and mass transfer ‎[25]. also, the adsorption rate and adsorption capacity increased in the case of using magnetic and mechanical stirrers. the size of adsorbent reduced and the adsorption sites were simply attainable to the adsorbate molecules ‎[26]. fig. 2. effect of different mixing techniques on the adsorption kinetics 4.2. effect of ph the adsorption of phenol mainly depends on the hydrogen ion concentration of the solution. fig. 3 was shown the effect of changing ph on the adsorption capacity of phenol by paper. this figure shows the removal percentages of phenol from solution increased in the range 40%, 60%, 77%, 81% as ph changed in the range 3, 5, 7, 9, respectively. and then the removal percentages reduced to 73% with ph equals 11. h. a. sabbar / iraqi journal of chemical and petroleum engineering 20,1 (2019) 23 – 29 42 hence, ph of 9 is the favorite. when ph ≤ 9, the phenolic compounds present as unionized acidic compounds and thereby the electrostatic attractions increase between the phenol and adsorption sites ‎[10]. phenol is a weak acid with acid dissociation value (pka) equals to 9.8 and it dissociates into phenoxide ion when ph > pka. up to ph 9, the concentration of the negatively charged phenoxide ion increases and the electrostatic repulsions occur between the negative surface charge of the paper and the phenoxide anions in solution ‎[27]‎[28]. fig. 3. effect of ph solution on phenol removal efficiency 4.3. effect of initial phenol concentration the effect of phenol concentration on the removal efficiency by paper waste was studied at five different phenol concentrations (i.e. 30, 50, 70, 90, 120 ppm) and the results are shown in fig. 4, where, ph was fixed at 9 and ultrasonic device was chosen as it gave best results. the results show that increasing the initial phenol concentration decreased the removal efficiency from 87% to 69%. this effect is related to the increase in phenol concentration which leads to the saturation of unoccupied sites on the adsorbent surface at higher phenol concentrations‎[11]. in other words, decreasing the pollutant concentration in the wastewater increases the chance of adsorbate molecules to react with the available active sites on paper waste so, the adsorption rate increases ‎[29] ‎[3]. fig. 4. effect of initial phenol concentration on removal efficiency 4.4. effect of adsorbent dose the effect of adsorbent dosage on the adsorption of the phenol was studied at ph of 9, initial phenol concentration of 30 ppm and using an ultrasonic device. the results of the phenol adsorption are shown in fig. 5. it is found that the removal of phenol increased from 44% to 88% when the adsorbent dose increased from 0.5 to 2 g. this can be explained as increased in the adsorbed phenol molecules are due to increasing the number of active sites ‎[30]. when the adsorbent dose beyond 2 g/l has no significant effect on the adsorption of phenol. this is due to the adsorption of the all phenol molecules present in the solution by the waste paper;‎[2]. fig. 5. effect of adsorbent dose on removal efficiency 4.5. effect of contact time time is an important parameter affecting the adsorption of phenol on an adsorbent. fig. 6 shows that phenol removal increased from 15% to 80% with increasing time from 30 to 120 min and the adsorption reached an equilibrium at about 120 min which is the maximum adoption ‎[31]. the performance of adsorption and the adsorption capacity highly increase over time until the equilibrium is attained. it was stated that the reason behind their findings was the formation of a layer of phenol on the adsorbent ‎[14]. fig. 6. effect of time on removal efficiency h. a. sabbar / iraqi journal of chemical and petroleum engineering 20,1 (2019) 23 – 29 42 5adsorption isotherm the information obtained from adsorption isotherm is required for designing the adsorption equipment and describing the nature of the interaction between adsorbent and adsorbate molecules at equilibrium ‎[23]. two isotherm models namely freundlich and langmuir models were applied on the adsorbate-adsorbent interaction. they give an equilibrium relationship between the adsorbate adsorbed on the adsorbent and adsorbate remaining in the solution ‎[1]. the results show that the experimental equilibrium data (shown in table 2 and fig. 7, fig. 8 and fig. 9) were accepted to the freundlich and langmuir isotherm equations; but freundlich isotherm model provides higher r 2 than langmuir isotherm model. the isotherm constants calculated from the model are shown in table 2. fig. 7. adsorption isotherm model of phenol fig. 8. langmuir adsorption isotherms for phenol adsorption fig. 9. freundlich adsorption isotherm for phenol adsorption table 2. isotherm constants for phenol removal by waste paper langmuir isotherm freundlich isotherm qm kl r 2 kf n r 2 7.0274 0.0401 0.9646 1.338 3.124 0.9897 6conclusions recently, high costs and environmental respects concomitant with using of commercial adsorbents has led to a major value of research effort aiming to develop novel cheap adsorbents resulting from renewable resources. in our work, paper waste can be used as an effective adsorbent for phenol elimination from aqueous solution. it was found that the amount of phenol adsorbed depended on several parameters such as the type of agitation techniques, ph, adsorbent dosage, initial phenol concentration and contact time. the final outcomes obtained from this work were well submitted by freundlich isotherm. the high removal efficiency of 86.4% was obtained using ultrasonic wave device, ph of 9, initial phenol concentration of 30 ppm, a paper waste dose of 1 g, and contact time of 120 min) references [1] girisha, c. r., purushottam singha, and ashish kumar goyala. "removal of phenol from wastewater using tea waste and optimization of conditions using response surface methodology." international journal of applied engineering research 12.13 (2017): 38573863. [2] ali, ashraf, and khalid saeed. "phenol removal from aqueous medium using chemically modified banana peels as low-cost adsorbent." desalination and water treatment 57.24 (2016): 11242-11254. [3] c. r. girish and v. r. murty, “adsorption of phenol from aqueous solution using lantana camara , forest waste : kinetics , isotherm , and thermodynamic studies,” vol. 2014, 2014. 0 1 2 3 4 5 6 7 0 50 100 150 q e ce y = 0.3201x + 0.1265 r² = 0.9897 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.5 2 2.5 lo g q e log ce https://www.ripublication.com/ijaer17/ijaerv12n13_41.pdf https://www.ripublication.com/ijaer17/ijaerv12n13_41.pdf https://www.ripublication.com/ijaer17/ijaerv12n13_41.pdf https://www.ripublication.com/ijaer17/ijaerv12n13_41.pdf https://www.ripublication.com/ijaer17/ijaerv12n13_41.pdf https://www.ripublication.com/ijaer17/ijaerv12n13_41.pdf https://www.tandfonline.com/doi/abs/10.1080/19443994.2015.1041057 https://www.tandfonline.com/doi/abs/10.1080/19443994.2015.1041057 https://www.tandfonline.com/doi/abs/10.1080/19443994.2015.1041057 https://www.tandfonline.com/doi/abs/10.1080/19443994.2015.1041057 https://www.hindawi.com/journals/isrn/2014/201626/abs/ https://www.hindawi.com/journals/isrn/2014/201626/abs/ https://www.hindawi.com/journals/isrn/2014/201626/abs/ https://www.hindawi.com/journals/isrn/2014/201626/abs/ h. a. sabbar / iraqi journal of chemical and petroleum engineering 20,1 (2019) 23 – 29 42 [4] asgari, ghorban, et al. "adsorption of phenol from aqueous solution by modified zeolite with fecl 3." international journal of environmental health engineering 2.1 (2013): 6. . [5] he, di, et al. "influence of different nominal molecular weight fractions of humic acids on phenol oxidation by permanganate." environmental science & technology 43.21 (2009): 8332-8337. . [6] kujawski, wojciech, et al. "removal of phenol from wastewater by different separation techniques." desalination 163.1-3 (2004): 287-296. [7] el-naas, muftah h., shaheen a. al-muhtaseb, and souzan makhlouf. "biodegradation of phenol by pseudomonas putida immobilized in polyvinyl alcohol (pva) gel." journal of hazardous materials 164.2-3 (2009): 720-725. [8] ugurlu, m., et al. "the removal of lignin and phenol from paper mill effluents by electrocoagulation." journal of environmental management 87.3 (2008): 420-428. [9] gomez, m., et al. "degradation of phenolic pollutants using krcl and xebr excilamps in the presence of dye: a comparative study." desalination 274.1-3 (2011): 156-163. [10] xu, jin-quan, et al. "extraction of phenol in wastewater with annular centrifugal contactors." journal of hazardous materials131.1-3 (2006): 98-102. [11] yang, k. u. n., et al. "aqueous adsorption of aniline, phenol, and their substitutes by multi-walled carbon nanotubes." environmental science & technology 42.21 (2008): 7931-7936. [12] a. auwal and j. hossen, “removal of phenol from aqueous solution using tamarind seed powder as adsorbent,” vol. 12, no. 3, 2018 pp. 41–48. [13] sarker, nandita, and a. n. m. fakhruddin. "removal of phenol from aqueous solution using rice straw as adsorbent." applied water science 7.3 (2017): 1459-1465. [14] biglari, hamed, et al. "phenol removal from aqueous solutions by adsorption on activated carbon of miswaks root treated with kmno4." iranian journal of health sciences 4 (2016). [15] d. n. jadhav and a. k. vanjara, “removal of phenol from wastewater using sawdust , polymerized sawdust and sawdust carbon,” vol. 11, no. january, 2004, pp. 35–41. [16] potgieter, j. h., s. o. bada, and s. s. potgietervermaak, “adsorptive removal of various phenols from water by south african coal fly ash,” vol. 35, no. 1 , 2009, pp. 89–96. [17] m. molva, d. submitted, p. fulfillment, e. e. major, e. engineering, and e. pollution, “removal of phenol from industrial wastewaters using lignitic coals,” 2004. [18] liu, yi, et al. "adsorption of methylene blue by kapok fiber treated by sodium chlorite optimized with response surface methodology." chemical engineering journal 184 (2012): 248-255. [19] wang, y. h., et al. "removal of trace organic compounds from wastewater by ultrasonic enhancement on adsorption." desalination 186.1-3 (2005): 89-96. [20] adill h.s. "removal of emulsified oil from water by activated carbon prepared from of scrap tires" m.sc. thesis, 2016, university of baghdad. college of engineering. [21] fahad, besma mohammed, nisreen sabah ali, and tamarah tareq hameed. "using paper waste as adsorbent for methyl violet dye removal from waste water." journal of engineering and sustainable development 22.1 (2018): 1-11. [22] c. r. girish and v. r. murty, “adsorption of phenol from aqueous solution using lantana camara , forest waste : kinetics , isotherm , and thermodynamic studies,” vol. 2014, 2014. [23] majeed, najwa saber, huda adil sabbar, and nawar oa al-musawi. "preparation activated carbon from scrap tires by microwave assisted koh activation for removal emulsified oil." iraqi journal of chemical and petroleum engineering 18.1 (2017): 57-69. [24] nwabanne, j. t., and p. k. igbokwe. "kinetics and equilibrium modeling of nickel adsorption by cassava peel." j. eng. applied sci 3.11 (2008): 829834. [25] awad, t. s., et al. "applications of ultrasound in analysis, processing and quality control of food: a review." food research international 48.2 (2012): 410-427. [26] kuśmierek, krzysztof, and andrzej świątkowski. "the influence of different agitation techniques on the adsorption kinetics of 4chlorophenol on granular activated carbon." reaction kinetics, mechanisms and catalysis 116.1 (2015): 261-271. [27] tan, i. a. w., a. l. ahmad, and b. h. hameed. "adsorption isotherms, kinetics, thermodynamics and desorption studies of 2, 4, 6-trichlorophenol on oil palm empty fruit bunch-based activated carbon." journal of hazardous materials 164.2-3 (2009): 473-482. [28] srivastava, vimal c., et al. "adsorptive removal of phenol by bagasse fly ash and activated carbon: equilibrium, kinetics and thermodynamics." colloids and surfaces a: physicochemical and engineering aspects 272.1-2 (2006): 89-104. [29] karagöz, selhan, et al. "activated carbons from waste biomass by sulfuric acid activation and their use on methylene blue adsorption." bioresource technology 99.14 (2008): 6214-6222. [30] özer, dursun, gülbeyi dursun, and ahmet özer. "methylene blue adsorption from aqueous solution by dehydrated peanut hull." journal of hazardous materials 144.1-2 (2007): 171-179. [31] mohammed, abdul-halim ak, samar k. theydan, and muthanna j. ahmed. "adsorption of phenol and pnitro phenol onto date stones: equilibrium isotherms, kineticsand thermodynamics studies." journal of engineering 18.6 (2012): 743-761. http://www.ijehe.org/article.asp?issn=2277-9183;year=2013;volume=2;issue=1;spage=6;epage=6;aulast=asgari http://www.ijehe.org/article.asp?issn=2277-9183;year=2013;volume=2;issue=1;spage=6;epage=6;aulast=asgari http://www.ijehe.org/article.asp?issn=2277-9183;year=2013;volume=2;issue=1;spage=6;epage=6;aulast=asgari http://www.ijehe.org/article.asp?issn=2277-9183;year=2013;volume=2;issue=1;spage=6;epage=6;aulast=asgari https://pubs.acs.org/doi/abs/10.1021/es901700m https://pubs.acs.org/doi/abs/10.1021/es901700m https://pubs.acs.org/doi/abs/10.1021/es901700m https://pubs.acs.org/doi/abs/10.1021/es901700m https://www.sciencedirect.com/science/article/pii/s0011916404902020 https://www.sciencedirect.com/science/article/pii/s0011916404902020 https://www.sciencedirect.com/science/article/pii/s0011916404902020 https://www.sciencedirect.com/science/article/pii/s0304389408012624 https://www.sciencedirect.com/science/article/pii/s0304389408012624 https://www.sciencedirect.com/science/article/pii/s0304389408012624 https://www.sciencedirect.com/science/article/pii/s0304389408012624 https://www.sciencedirect.com/science/article/pii/s0304389408012624 https://www.sciencedirect.com/science/article/pii/s030147970700031x https://www.sciencedirect.com/science/article/pii/s030147970700031x https://www.sciencedirect.com/science/article/pii/s030147970700031x https://www.sciencedirect.com/science/article/pii/s030147970700031x https://www.sciencedirect.com/science/article/pii/s0011916411001305 https://www.sciencedirect.com/science/article/pii/s0011916411001305 https://www.sciencedirect.com/science/article/pii/s0011916411001305 https://www.sciencedirect.com/science/article/pii/s0011916411001305 https://www.sciencedirect.com/science/article/pii/s030438940500542x https://www.sciencedirect.com/science/article/pii/s030438940500542x https://www.sciencedirect.com/science/article/pii/s030438940500542x https://pubs.acs.org/doi/abs/10.1021/es801463v https://pubs.acs.org/doi/abs/10.1021/es801463v https://pubs.acs.org/doi/abs/10.1021/es801463v https://pubs.acs.org/doi/abs/10.1021/es801463v https://www.researchgate.net/profile/jewel_hossen/publication/328723433_removal_of_phenol_from_aqueous_solution_using_tamarind_seed_powder_as_adsorbent/links/5bddaf7d4585150b2b9bc11c/removal-of-phenol-from-aqueous-solution-using-tamarind-seed-powder-as-adsorbent.pdf https://www.researchgate.net/profile/jewel_hossen/publication/328723433_removal_of_phenol_from_aqueous_solution_using_tamarind_seed_powder_as_adsorbent/links/5bddaf7d4585150b2b9bc11c/removal-of-phenol-from-aqueous-solution-using-tamarind-seed-powder-as-adsorbent.pdf https://www.researchgate.net/profile/jewel_hossen/publication/328723433_removal_of_phenol_from_aqueous_solution_using_tamarind_seed_powder_as_adsorbent/links/5bddaf7d4585150b2b9bc11c/removal-of-phenol-from-aqueous-solution-using-tamarind-seed-powder-as-adsorbent.pdf https://link.springer.com/article/10.1007/s13201-015-0324-9 https://link.springer.com/article/10.1007/s13201-015-0324-9 https://link.springer.com/article/10.1007/s13201-015-0324-9 https://link.springer.com/article/10.1007/s13201-015-0324-9 http://jhs.mazums.ac.ir/browse.php?a_code=a-10-476-5&slc_lang=en&sid=1 http://jhs.mazums.ac.ir/browse.php?a_code=a-10-476-5&slc_lang=en&sid=1 http://jhs.mazums.ac.ir/browse.php?a_code=a-10-476-5&slc_lang=en&sid=1 http://jhs.mazums.ac.ir/browse.php?a_code=a-10-476-5&slc_lang=en&sid=1 http://jhs.mazums.ac.ir/browse.php?a_code=a-10-476-5&slc_lang=en&sid=1 http://nopr.niscair.res.in/handle/123456789/9486 http://nopr.niscair.res.in/handle/123456789/9486 http://nopr.niscair.res.in/handle/123456789/9486 http://nopr.niscair.res.in/handle/123456789/9486 https://www.ajol.info/index.php/wsa/article/view/76646 https://www.ajol.info/index.php/wsa/article/view/76646 https://www.ajol.info/index.php/wsa/article/view/76646 https://www.ajol.info/index.php/wsa/article/view/76646 http://openaccess.iyte.edu.tr/handle/11147/3256 http://openaccess.iyte.edu.tr/handle/11147/3256 http://openaccess.iyte.edu.tr/handle/11147/3256 http://openaccess.iyte.edu.tr/handle/11147/3256 https://www.sciencedirect.com/science/article/pii/s1385894712000526 https://www.sciencedirect.com/science/article/pii/s1385894712000526 https://www.sciencedirect.com/science/article/pii/s1385894712000526 https://www.sciencedirect.com/science/article/pii/s1385894712000526 https://www.sciencedirect.com/science/article/pii/s0011916405006843 https://www.sciencedirect.com/science/article/pii/s0011916405006843 https://www.sciencedirect.com/science/article/pii/s0011916405006843 https://www.sciencedirect.com/science/article/pii/s0011916405006843 https://www.iasj.net/iasj?func=article&aid=139484 https://www.iasj.net/iasj?func=article&aid=139484 https://www.iasj.net/iasj?func=article&aid=139484 https://www.iasj.net/iasj?func=article&aid=139484 https://www.iasj.net/iasj?func=article&aid=139484 https://link.springer.com/article/10.1007/s40710-015-0117-z https://link.springer.com/article/10.1007/s40710-015-0117-z https://link.springer.com/article/10.1007/s40710-015-0117-z https://link.springer.com/article/10.1007/s40710-015-0117-z https://www.iasj.net/iasj?func=article&aid=123026 https://www.iasj.net/iasj?func=article&aid=123026 https://www.iasj.net/iasj?func=article&aid=123026 https://www.iasj.net/iasj?func=article&aid=123026 https://www.iasj.net/iasj?func=article&aid=123026 https://www.iasj.net/iasj?func=article&aid=123026 http://docsdrive.com/pdfs/medwelljournals/jeasci/2008/829-834.pdf http://docsdrive.com/pdfs/medwelljournals/jeasci/2008/829-834.pdf http://docsdrive.com/pdfs/medwelljournals/jeasci/2008/829-834.pdf http://docsdrive.com/pdfs/medwelljournals/jeasci/2008/829-834.pdf https://www.sciencedirect.com/science/article/pii/s096399691200141x https://www.sciencedirect.com/science/article/pii/s096399691200141x https://www.sciencedirect.com/science/article/pii/s096399691200141x https://www.sciencedirect.com/science/article/pii/s096399691200141x https://link.springer.com/article/10.1007/s11144-015-0889-1 https://link.springer.com/article/10.1007/s11144-015-0889-1 https://link.springer.com/article/10.1007/s11144-015-0889-1 https://link.springer.com/article/10.1007/s11144-015-0889-1 https://link.springer.com/article/10.1007/s11144-015-0889-1 https://link.springer.com/article/10.1007/s11144-015-0889-1 https://www.sciencedirect.com/science/article/pii/s0304389408012235 https://www.sciencedirect.com/science/article/pii/s0304389408012235 https://www.sciencedirect.com/science/article/pii/s0304389408012235 https://www.sciencedirect.com/science/article/pii/s0304389408012235 https://www.sciencedirect.com/science/article/pii/s0304389408012235 https://www.sciencedirect.com/science/article/pii/s0927775705005352 https://www.sciencedirect.com/science/article/pii/s0927775705005352 https://www.sciencedirect.com/science/article/pii/s0927775705005352 https://www.sciencedirect.com/science/article/pii/s0927775705005352 https://www.sciencedirect.com/science/article/pii/s0927775705005352 https://www.sciencedirect.com/science/article/pii/s0960852407010292 https://www.sciencedirect.com/science/article/pii/s0960852407010292 https://www.sciencedirect.com/science/article/pii/s0960852407010292 https://www.sciencedirect.com/science/article/pii/s0960852407010292 https://www.sciencedirect.com/science/article/pii/s0304389406012003 https://www.sciencedirect.com/science/article/pii/s0304389406012003 https://www.sciencedirect.com/science/article/pii/s0304389406012003 https://www.sciencedirect.com/science/article/pii/s0304389406012003 https://www.iasj.net/iasj?func=article&aid=41390 https://www.iasj.net/iasj?func=article&aid=41390 https://www.iasj.net/iasj?func=article&aid=41390 https://www.iasj.net/iasj?func=article&aid=41390 https://www.iasj.net/iasj?func=article&aid=41390 h. a. sabbar / iraqi journal of chemical and petroleum engineering 20,1 (2019) 23 – 29 42 امتزاز الفينول من مياه الصرف الصحي باستعمال المخلفات الورقية الخالصة ر القابمة لمتدوير ومنها المخمفات الورقية له مميزات في حماية البيئة ومواردها. وقد مصادإن استغالل ال المتصاص الفينول الذي يعد واحد من المنتجات العضوية المخمفات الورقيةأجريت ا لدراسة عمى استخدام ( ، تركيز 11-3)الضارة عمى البيئة. تمت دراسة تأثير اختالف طرق الخمط ودرجة الحموضة من المحمول 100-30جم( ووقت االتصال ) 2.0-0.0جزء في المميون( ، كتمة المادة المازة) 120-30الفينول األولي ) دقيقة(. ممغم / غم و 0.1% وسعة االمتزاز قدرها 68أعمى كفاءة إلزالة الفينول تم الحصول عميها كانت 120جم وزمن االتصال 2، جرعة ممتزة من 30نول ، تركيز أولي الفي 9الظروف المثمى )درجة الحموضة .أظهرت النجميور وفروندليتش اثناء االتزان دقيقة وفي درجة حرارة الغرفة( . تمت دراسة مالئمة نماذج امتزاز .( ضمن الحدود المدروسةr2=0.9897مع معامل تصحيح ) النتائج مالئمة فروندليتش vol.9 no.3 (september 2008) iraqi journal of chemical and petroleum engineering vol.9 no.3 (september 2008) 51-57 issn: 1997-4884 viscosity index improvement of lubricating oil fraction (sae – 30) abdul-halim abdul-karim mohammed * and amal khalid shehab al – rubai * chemical engineering department college of engineering university of baghdad – iraq abstract an investigation was conducted for the improvement of viscosity index of a lubricating oil fraction (sae – 30) obtained from vacuum distillation unit of lube oil plant of daura refinery, using solvent extraction process. in this study two type of extraction solvents were used to extract the undesirable materials which reduce the viscosity index of raw lubricating oil fraction, the first solvent was furfural which is un use today in the iraqi refineries and the second was nmp (n-methyl, 2, pyrrolidone) which is used for the first time in this work to extract the lubricating oil fraction produced from iraqi crude oils. the studied effecting variables of extraction are extraction temperature range from 70 to 110 oc for furfural and nmp extraction, solvent to oil ratio range from 1:1 to 5:1 (wt/wt) for furfural extraction and from 0.5:1 to 2:1 (wt/wt) for nmp extraction. the results of this investigation show that the viscosity index of lubricating oil fraction increases with increasing extraction temperature and increasing the solvent to oil ratio and reaches 83 for nmp extraction at extraction temperature 110 oc and solvent to oil ratio 2:1, while the viscosity index reaches to 80 for furfural extraction at the same extraction temperature and solvent oil ratio. higher viscosity index of lubricating oil fraction is obtained by using nmp instead of furfural under the same operating variables (extraction temperature and solvent to oil ratio). further more, the results show that the viscosity, refractive index, and percentage yield of raffinate decreased as the extraction temperature or solvent to oil ratio increases for furfural and nmp extraction. introduction with the increasing demands for high quality lubricating oils to withstand the severe operating conditions of the modern gasoline and diesel engines, it become apparent that the selected crudes were no longer sufficient in either quantity or quality to supply the demand. therefore, it was obvious that the petroleum industry would have to resort to some means for separation of the desirable and undesirable component of lubricating oil stocks. other than the heavy asphaltic materials and the normally solid paraffin waxes, which be removed by precipitation or by filtration at reduced temperatures, the undesirable components comprise those aromatic type hydrocarbons which possess low oiliness, low viscosity index, poor oxidation stability, high carbon residue, and poor color [1]. solvent treating is the most widely used method of refining lubricating oils. these processes yield products that meet the requirements of a modern lubricant by removing from the charge material those undesirable constituents. the solvent – treated lubricating oils have higher viscosity indexes, greater resistance to gum and sludge formation by oxidation, and increased susceptibility to further improvement by addition of selective additives [2]. although no solvent meets all of the requirements of the ideal extraction solvents have been proposed and used commercially. the major solvents in use today are n – methyl – 2 – pyrrolidone and furfural, with phenol and liquid sulfur dioxide being used to a lesser extent [3]. the present work deals with viscosity index improvement of lubricating oil fraction sae – 30 obtained from vacuum distillation unit of lube oil plant of daura refinery, by extremely selective solvent extraction process using furfural and n – methyl – 2 – pyrrolidone solvents. this work includes the study of the effects of extraction temperature and solvent to oil university of baghdad college of engineering iraqi journal of chemical and petroleum engineering viscosity index improvement of lubricating oil fraction (sae – 30) 52 vol.9 no.3 (september 2008) ratio on the physical properties and the percentage yield of the produced lubricating oil. experimental work feed stock a distillate lube oil fraction (sae – 30 distillate) obtained from vacuum distillation unit of lube oil plant of daura refinery was used in this work. atmospheric residue produced from mixed iraqi crude oil (60 % of basrah crude, 30 % of kirkuk crude, and 10 % of sharki – baghdad crude) was the feed stock for vacuum distillation unit. table (1) shows the properties of the lube oil fraction. table 1 properties of lube oil fraction no. specification lube oil fraction 1 specific gravity @ 60/60 o f 0.91705 2 viscosity, cst, @ 40 o c 118.00 3 viscosity, cst, @ 100 o c 9.39 4 viscosity index 26 5 coc flash point, o c 242 6 pour point, o c 25 7 color astm – d 1500, @ 50 o c 5.5 8 sulfur content, % wt. 3.073 solvents two solvents were used in this work. these solvents are furfural (liaosin private limited company, china) and nmp (fluka chemicals ag, germany). table (2) shows the measured properties of these solvent. table 2 properties of furfural and nmp no. specification furfural nmp 1 density ( 25 4 d ), g/cm3 1.1563 1.0270 2 boiling point, o c 161 202 3 refractive index ( 25 d n ) 1.5235 1.4690 4 coc flash point, o c 68 95 5 freezing point, o c -36.5 -24 6 viscosity, cps, @ 25 o c 1.49 1.65 extraction experiments figure (1) shows the schematic diagram of the laboratory batch extraction unit. this unit consists of a bench scale jacketed glass column extraction apparatus with 50 mm id, 700 mm length, 80 mm jacket id and 2 mm wall thickness. the jacketed extractor was heated and controlled by circulating hot oil through the jacket. the solvent was stripped from the raffinate using distillation with nitrogen. fig.1: the schematic diagram of the laboratory batch extraction unit figure (1) shows the schematic diagram of the laboratory batch extraction unit. this unit consists of a bench scale jacketed glass column extraction apparatus with 50 mm id, 700 mm length, 80 mm jacket id and 2 mm wall thickness. the jacketed extractor was heated and controlled by circulating hot oil through the jacket. the solvent was stripped from the raffinate using distillation with nitrogen. extraction experiments conditions in the present work, the experiments that applied on the extraction of lube oil distilled fraction were classified in to two categories. the first one was applied on furfural as extraction solvent. the operating conditions are extraction temperature range from 70 to 110 oc, solvent mixer heating bath circular pump • abdul-halim abdul-karim mohammed*and amal khalid shehab al – rubai 53 vol.9 no.3 (september 2008) to oil ratio from 1:1 to 5:1 (wt. / wt.), and using atmospheric pressure. the second set of experiments applied on nmp as the extraction solvent. the extraction temperature was the same as for the first set but the solvent to oil ratio were reduced to 0.5:1 to 2:1 because of the higher solvent power of nmp than furfural [4]. test methods 1 viscosity the viscosity of feed stock, and raffinate were determined by capillary u-tube viscometer according to astm d-445 [5]. 2 viscosity index the raffinate viscosity index was determined by measuring the raffinate refractive index and from the data relating the refractive index to viscosity index tabulated in table (3) (6), the refractive index was determined according to astm d-1747 [5]. the feed stock has a color greater than no. 4 according to astm color – d1500, therefore the viscosity index can not be determined by measuring the refractive index. also the viscosity at 40 oc of waxy feed can not be measured, therefore the viscosity of the feed stock was measured at 80 and 100 oc to obtain the viscosity at 40 oc using the viscosity – temperature charts of liquid petroleum products according to astm – d341 (5).. the viscosity index of the feed stock fraction was calculated according to astm – d2270 (5) by applying the procedure for oils of zero to 100 vi. in this procedure equation (1) was used. 100 hl ul vi     (1) where u :kinematic viscosity at 40 °c of the oil whose viscosity index to be calculated (cst). l : kinematic viscosity at 40°c of an oil of zero viscosity index having the same kinematic viscosity at 100°c as the oil whose viscosity index is to be calculated (cst). h :kinematic viscosity at 40 °c of an oil of 100 viscosity index having the same kinematic viscosity at 100 °c as the oil whose viscosity index is to be calculated (cst). table 3 raffinate refractive index and viscosity index [6] ri vi ri vi 1.4560 103 1.4690 86 1.4565 102 1.4700 85 1.4570 101 1.4708 84 1.4575 100 1.4715 83 1.4580 99 1.4720 82 1.4590 98 1.4730 81 1.44600 97 1.4740 80 1.4610 96 1.4745 79 1.4625 94 1.4765 77 1.4630 93 1.4770 76 1.4640 92 1.4780 75 1.4650 91 1.4790 74 1.4655 90 1.4795 73 1.4665 89 1.4805 72 1.4675 88 1.4815 71 1.468 87 1.4820 70 results and discussion effect of operating variables and solvent type on raffinate viscosity the viscosity of lubricating oil fraction is a very important factor in the manufacturing of lubricating oils, and the correct operation of the equipment depends upon the appropriate viscosity of the lubricating oil being used. in the present work the effect of extraction temperature and solvent to oil ratio on raffinate kinematic viscosity at 100 oc were studied. figures (2 and 3) show the effect of extraction temperature on raffinate viscosity for furfural and nmp extraction respectively, while figures (4 and 5) show the effect of solvent to oil ratio on raffinate viscosity for furfural and. in general, the viscosity of raffinate produced from furfural or nmp extraction decreased with increasing the extraction temperature or increasing the solvent to oil ratio and that is due to the extraction of aromatic materials especially polycondensed aromatics from the raw lubricating oil fraction. the aromatics have the higher viscosity among the hydrocarbons that presented in raw lubricating oils and the extraction of these materials decrease its content in the produced raffinate and increase the paraffins content which have a viscosity relatively lower than that of aromatics as mentioned by kosters [7]. viscosity index improvement of lubricating oil fraction (sae – 30) 54 vol.9 no.3 (september 2008) figures (2 and 3), clearly indicate that the extraction temperature slightly affect the viscosity of raffinate produced from furfural and nmp extraction for a given solvent to oil ratio. figures (4 and 5) show that the increase in solvent to ratio for a given extraction temperature have higher effect in decreasing the raffinate viscosity obtained by furfural and nmp extraction. the viscosity of the raffinate produced from nmp extraction is slightly lower than that produced from furfural extraction using the same operating variables, because of the higher activity and high solvent power of nmp than furfural [4]. fig.2: effect of extraction temperature on raffinate viscosity at different solvent to oil ratio for furfural extraction figure (4) effect of solvent to oil ratio on raffinate viscosity at various extraction temperature for furfural extraction fig.4: effect of solvent to oil ratio on raffinate viscosity at various extraction temperature for furfural extraction fig.5: effect of solvent to oil ratio on raffinate viscosity at various extraction temperature for nmp extraction effect of operating variables and solvent type on raffinate viscosity index the viscosity index of lubricating oil reflects the ability of lube oil viscosity to vary with temperature. figures (6 and 7) show the effect of extraction temperature on raffinate viscosity index for furfural and nmp extraction respectively at various solvent to oil ratio. figures (8 and 9) show the effect of solvent to oil ratio on raffinate viscosity index for furfural and nmp extraction respectively at various extraction temperature. the increase in extraction temperature will encourage the solubility of undesirable materials especially polycondensed aromatics (which reduce the viscosity index of lubricating oil) in extraction solvent. it is obvious from figures (6 and 7) that the viscosity index of lubricating oil fraction increase with increasing the extraction temperature. the increase of extraction temperature 10 oc will increase the viscosity index one temperature , o c visc osity , cst . 8.2 8.4 8.6 8.8 9.0 9.2 9.4 65 75 85 95 105 115 1:1 2:1 3:1 4:1 5:1 temperature , o c visc osity , cst . 7.8 8.2 8.6 9.0 9.4 9.8 65 75 85 95 105 115 0.50:1 0.72:1 1.25:1 1.78:1 2.00:1 solvent to oil ratio , wt/wt visc osity , cs t. 8.2 8.4 8.6 8.8 9.0 9.2 9.4 1:1 2:1 3:1 4:1 5:1 70 o c 80 o c 90 o c 100 o c 110 o c solvent to oil ratio ,wt/wt visc osity ,cst. 7.8 8.2 8.6 9.0 9.4 9.8 0.5:1 0.72:1 1.25:1 1.78:1 2.0:1 70 o c 76 o c 90 o c 104 o c 110 o c abdul-halim abdul-karim mohammed*and amal khalid shehab al – rubai 55 vol.9 no.3 (september 2008) point for a given solvent to oil ratio using furfural and nmp as extraction solvents. figures (8 and 9) indicate that the increasement in solvent to oil ratio has a high effect on increasing the viscosity index of lubricating oil fraction compared with extraction temperature in furfural and nmp extraction. in case of using furfural as extraction solvent, the significant solvent to oil ratio is higher than 1:1 because of the constancy of the viscosity index on a fixed value using different extraction temperatures and that is due to the saturation of this amount of furfural with undesirable materials. the increase in raffinate viscosity index related to the reduction in naphthene – aromatic and polar aromatic content and the increase in saturates content in the produced raffinate. the higher solvent power of nmp compared with furfural gave higher viscosity index using the same operating variables. these results are in agreement with those obtained by sequeira and sherman (4) which approved that the solvent power is better (solvent to oil ratio is lower) for nmp than for furfural. fig.6: effect of extraction temperature on raffinate viscosity index at various solvent to oil ratio for furfural extraction fig.7: effect of extraction temperature on raffinate viscosity index at various solvent to oil ratio for nmp extraction fig .8: effect of solvent to oil ratio on raffinate viscosity index at various extraction temperatures for furfural extraction fig .9: effect of solvent to oil ratio on raffinate viscosity index at various extraction temperatures for nmp extraction effect of operating variables and solvent type on raffinate yield many factors controlling the convential operating conditions of solvent extraction. one of these important factors affecting the overall process performance is the lubricating oil yield. figures (10 and 11) show the effect of extraction temperature on raffinate yield at various solvent to oil ratio for furfural and nmp extraction. it appears from these figures that the yield percentage decreases as the extraction temperature increased but that effect is some what little in comparison with the effect of solvent to oil ratio. figures (12 and 13) show the effect of increasing solvent to oil ratio on decreasing the raffinate yield percentage at various extraction temperatures for furfural and nmp extraction respectively. temperature, o c vis cosi ty in dex 68 72 76 80 84 88 92 65 75 85 95 105 115 1:1 2:1 3:1 4:1 5:1 temperature , o c visc osity inde x 50 56 62 68 74 80 86 65 75 85 95 105 115 0.50:1 0.72:1 1.25:1 1.78:1 2.00:1 solvent to oil ratio ,wt/wt vis cosi ty in dex 68 72 76 80 84 88 92 1:1 2:1 3:1 4:1 5:1 70 o c 80 o c 90 o c 100 o c 110 o c solvent to oil ratio ,wt/wt visco sity i ndex 50 56 62 68 74 80 86 0.5:1 0.72:1 1.25:1 1.78:1 2.0:1 70 o c 76 o c 90 o c 104 o c 110 o c temperature, o c yiel d ,% wt 52 56 60 64 68 72 76 80 84 65 75 85 95 105 115 1:1 2:1 3:1 4:1 5:1 solvent to oil ratio ,wt/wt yield ,%wt 66 70 74 78 82 86 90 0.50:1 0.72:1 1.25:1 1.78:1 2.00:1 70 o c 76 o c 90 o c 104 o c 110 o c viscosity index improvement of lubricating oil fraction (sae – 30) 56 vol.9 no.3 (september 2008) solvent to oil ratio , wt/wt yiel d , % wt 52 56 60 64 68 72 76 80 84 1:1 2:1 3:1 4:1 5:1 70 o c 80 o c 90 o c 100 o c 110 o c solvent to oil ratio,wt/wt visco sity i ndex 68 70 72 74 76 78 80 82 1.00:1 1.25:1 1.75:1 2.00:1 nmp furf figure (10) effect of extraction temperature on raffinate yield at various solvent to oil ratio for furfural extraction figure (11) effect of extraction temperature on raffinate yield at various solvent to oil ratio for nmp extraction figure (12) effect of solvent to oil ratio on raffinate yield at various extraction temperatures for furfural extraction figure (13) effect of solvent to oil ratio on raffinate yield at various extraction temperatures for nmp extraction comparison of furfural and nmp extraction for the purpose of selecting the most efficient solvent for the extraction of undesirable materials presented in raw lubricating oil fraction used in this study, a comparison between the viscosity index and percentage yield of raffinates produced from furfural and nmp extraction process were included in this investigation. the comparison was taken place at extraction temperature of 90 oc and solvent to oil ratio in the range 1:1 to 2:1 for furfural and nmp extraction. figure (14) show the effect of increasing the solvent to oil ratio on raffinate viscosity index for furfural and nmp extraction at 90 oc, while figure (15) shows the effect of increasing solvent to oil ratio on raffinate yield for furfural and nmp extraction at 90 oc. figure (14) indicates that the raffinate viscosity index produced from furfural extraction is slightly higher than that produced from nmp extraction in solvent to oil ratio lower than 1.5:1, above this ratio the viscosity index of nmp becomes higher than that of furfural extraction and reaches 80 for nmp raffinate and 77 for furfural raffinate at 2:1 solvent to oil ratio. figure (15) show that the raffinate yield produced from furfural extraction is higher than that produced from nmp extraction but at solvent to oil ratio 2:1 an equivalent yield was obtained from furfural and nmp extraction. if the extraction temperature increase to 110 oc, the raffinate yield for nmp extraction becomes higher than that for furfural extraction at solvent to oil ratio above 1.5:1 and the raffinate viscosity index reaches to 83 for nmp extraction and 80 for furfural extraction at 2:1 solvent to oil ratio. from the above mentioned discussion it may be concluded that nmp was the most efficient solvent for the extraction of lubricating oil fraction used in this study because of the following: low solvent to oil ratio can be used to produce the same raffinate viscosity index. an equivalent or higher raffinate yield obtained from nmp extraction at solvent to oil ratio higher than 2.0:1.0. low solvent toxicity. better heat stability because of high boiling point. figure (14) effect of solvent to oil ratio on raffinate viscosity index for furfural and nmp extraction at 90 oc temperature, o c yield ,%wt 66 70 74 78 82 86 90 65 75 85 95 105 115 0.50:1 0.72:1 1.25:1 1.78:1 2.00:1 abdul-halim abdul-karim mohammed*and amal khalid shehab al – rubai 57 vol.9 no.3 (september 2008) figure (15) effect of solvent to oil ratio on raffinate yield for furfural and nmp extraction at 90 oc conclusions 1. the viscosity index of lubricating oil fraction increases from 26 to 71 as a minimum for furfural extraction at 70 oc and 1:1 solvent to oil ratio and reaches 90 as a maximum at 110 oc and 5:1 solvent to oil ratio. 2. the viscosity index of lubricating oil fraction increases to 54 as a minimum for nmp extraction at 70 oc and 0.5:1 solvent to oil ratio and reaches 83 as a maximum at 110 oc and 2:1 solvent to oil ratio. 3. the raffinate viscosity index produced from nmp extraction was higher than that produced from furfural extraction at the solvent to oil ratio higher than 1.5:1 and reaches 83 and 80 for nmp and furfural extraction respectively at 2:1 solvent to oil ratio and 110 oc extraction temperature, while the raffinate yield is 68.69 % wt. and 65.66 % wt. for nmp and furfural extraction respectively using the same operating variables. a compromise should be performed between the desired viscosity index and lubricating oil yield. 4. the solvent to oil ratio has the higher influence on increasing the raffinate viscosity index and decreasing yield, viscosity, and refractive index for furfural and nmp extraction than extraction temperature. reference 1. kemp, l. c. et al., industrial and engineering chemistry, vol. 40, no. 2, p.p. 65 – 73, 1948. 2 bland and davidson, petroleum processing hand book, mc graw hill, new york, 1967. 3 mc ketta, encyclopedia of chemical processing and design, vol. 28, marcel dekker, inc., new york, 1988. 4 sequeira, a., sherman, p. b., j. v., and mc bride, e. o., hydrocarbon processing, vol. 58, no. 9, p.p. 155 – 160, 1979. 5 annual book of astm standards, vol. 05.01, 1994. 6 daura refinery, internal report, 1972. 7 kosters, w. c. g., chemistry and industry, vol. 15, no. 2, p.p. 220 – 223, 1977. solvent to oil ratio,wt/wt yield ,%wt 68 70 72 74 76 78 80 82 84 1.00:1 1.25:1 1.75:1 2.00:1 nmp furf iraqi journal of chemical and petroleum engineering vol.18 no.2 (june 2017) 27 39 issn: 1997-4884 effect of kaolinite on the mechanical properties, thermal properties, flammability and water absorption percentage of poly (vinyl chloride) composite basma a. abdul majeed and dhilal amer sabar chemical engineering department -college of engineering -university of baghdad-iraq abstract pvc/kaolinite composites were prepared by the melt intercalation method. mechanical properties, thermal properties, flammability and water absorption percentage of prepared samples were tested. mechanical characteristic such as tensile strength, elongation at break; hardness and impact strength (charpy type) were measured for all samples. it was found that the tensile strength and elongation at break of pvc composites decreased with increasing kaolinite loading. also, the hardness of the composites increases with increase in filler content .the impact strength of the composites at the beginning increases at lower kaolinite loadings is due to the lack of kaolin adhesion to the matrix. however, at higher kaolin loadings. this severe agglomeration of the filler due to its high surface energy creates many crack-initiation and stress-concentration sites, which are sensitive to impact stresses and cause detrimental effects on the impact properties of the composite. there is a general increase in absorption rate with increase in kaolin content. thermal properties of pvc /kaolinite composites were characterized using differential scanning calorimetry (dsc) and thermal conductivity analyzer. the results showed tg shifted toward higher temperature for kaolinite composites compared to neat pvc .also, thermal conductivity measurement value and effusivity increased with increasing filler loading .heat capacity decreased with increasing filler content. the higher the filler content the higher burning time, the lower rate of burning and the lower height of the flame which are evident at 12wt. % for kaolinite. key words: polymer, pvc/ kaolinite composites, mechanical properties, thermal properties. introduction the polymer is a word of a greek origin where “poly” is a synonym of” many”, while “meres” stands for “parts”, so a polymer is a large molecules consisting of repeated smaller size chemical units. they can be made into types of final products as it is the case with the pure (new) form. nonetheless, to make an effectively useful polymer, it is indispensable to modify it, particularly when the major limitations in the unmodified polymer are taken into account. among those restrictions may be the low stiffness, low strength and the lack of stability when exposed to light rays, heat and university of baghdad college of engineering iraqi journal of chemical and petroleum engineering effect of kaolinite on the mechanical properties, thermal properties, flammability and water absorption percentage of poly (vinyl chloride) composite 28 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net radiation that can ionize it. to make polymer vastly usable in different industrial fields nowadays, improved polymer composite productions are the right pathway to overcome the evident restrictions on one hand, and to insure the production of high quality polymers on the other [1]. a composite is defined as the combination at microscopic level between a couple (and more) of particular materials with a specific intervention to link them together. the material could be of a metal, ceramic or polymer nature [2]. nowadays, poly vinyl chloride occupies the third position in the list of the most commonly produced plastics, where the polyethylene comes at the top followed by polypropylene, by virtue of its valuable characteristics, wide applications, barrier properties, low cost and high chemical resistance. pvc is in the form of powders, slurries, liquids, and tablets. it has a wide range of properties of colors, solid, rigid, and stiff materials (with high viscosity) at room temperature, light weight with a good resistance to bases and acids, alcohol, oils, compound hydrocarbon aliphatic. pvc has relatively low cost, biological and chemical resistance and workability and can be formed easily. for these reasons it is used for a wide range of applications, such as insulation on electrical cables, solid pipe manufacturing, window frames and doors, bottles, containers, furniture industry, etc. [3] the thermal stability and processing of poly vinyl chloride, on the other hand, are unimportant in comparison with familiar polymers. these properties can be improved by making the poly vinyl chloride compound with some additives. the most commonly used additives in pvc are lubricants, heat stabilizers, plasticizers, fillers and pigments. either polymerization or melt blending processes are used [4, 5]. the kaolin is an ordinary phyllosilicate mineral, with a chemical formula al2si2o5 (oh) 4. this clay has 1:1 di-octahedral structure pattern consisting of tetrahedral sio4 and octahedral al2 (oh) 4 plates. specific layered consists of both of them which are neatly connected by the hydrogen bond between surface hydroxyl groups on the octahedral side and the basal oxygen atoms on the tetrahedral side. kaolin finds a number of industrial usages; in making paints, paper, plastics, rubber and ceramics. its largest viable usage as filler in pvc is in producing electrical cables or film anti blocking, tiles and so on [6, 7]. dibasic lead stearates (dbls), dibasic lead phosphate (dblp) are used as the stabilizer; stearic acid is used as a lubricant. dioctyl phthalate (dop) is used as a plasticizer for compounding. it is noticed that raising the pvc temperature to more than 70 0 c imposes some absurd changes on its properties. in practice, when temperatures of (150-200 0 c) are used, sufficient degradation may occur upon normal processing operation which makes the product useless [8, 9]. in this research, the pvc/kaolinite composite preparation by the melt intercalation method is reported. in addition the influence of untreated kaolinite on the mechanical properties, thermal properties, flammability and water absorption percentage of poly vinyl chloride is investigated. experimental work 1. materials the pvc powder, a suspension polymer, supplied by saudi basic industries corporation and kingdom http://www.iasj.net/ basma a. abdul majeed and dhilal amer sabar -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 29 of saudi arabia; the pvc used in this research has been analyzed by ftir. iraqi kaolin powder al2si2o5(oh)4 was brought from ministry of industry/ the state company of geological survey and mining. the specifications of the kaolin clay are given in table 1. additives such as: dibasic lead stearates (dbls) (2pbo.pb(c17h35coo)2), dibasic lead phosphate (dblp) (o8p2pb3) are used as the stabilizer; stearic acid (c18h36o2) is used as lubricant. these materials are from the ministry of industry /baghdad plastic plant. dioctyl phthalate (dop) (c6h4-1, 2[co2 ch2 ch (c2h5)(ch2)3ch3]2) used in this study was used as a plasticizer by indian company/ sigma ultra. table 1: the characteristics of the kaolin 2. methods  sample preparation the following couple of steps summarize the production of poly vinyl chloride composite [10]: in the first one, a 1% by weight of the stabilizer (dibasic lead stearate, dbls and dibasic lead phosphate, dblp) was added to the pvc powder. a 1% by weight of the stearic acid as a lubricant was also added. in addition to that, a percentage of 3%, 7% and 12% by weight of the filler were added. the filler used were bentonite and organoclay. the blend was mixed in a high_ speed mixer for 20 min forming a dry mixture. in the second step, the dry blend was blended with 20% by weight dioctyl phthalate (dop). the details of additives percentage are given in table 2. the blending took place in the plastograph internal mixer (plasticcorder), (bra bender .gmbh & co .kg, duisburg, germany, 0-1000 0 c) at (65-80 0 c) for 20 min and a 64-rpm mixing speed. table 2: pvc composite formulation with filler composition (%) material 1 2 3 4 pvc 100 100 100 100 stabilizer :dbls 1 1 1 1 stabilizer :dblp 1 1 1 1 lubricant: stearic acid 1 1 1 1 plasticizer :dop 20 20 20 20 kaolinite 0 3 7 12  compression molding (hot press) a hydraulic press figure 1 (made in englan, noore, birmingham and serial number /d369) was used to mold the sheets to be tested in this study. it consisted of lower and upper moving platens. a sample of the above mentioned mold was wrapped by an aluminum thin sheet [1]. using the controlled hydraulic ram, the lower platen was pushed toward the upper platen causing the mold to close and putting under pressure. the compression of the resulting film took place under the following conditions; a temperature of 170-185 0 c, and after pressure of 10 bars for 7 min. when the seven minutes, the pressure was removed letting the lower platen to fall down under the effect of gravity. the mold was dismantled rapidly and running water was used to cool it down. the aluminum foil paper was neatly un-wrapped to clear the produced film sample out of it. the compression-molded sheets of 90 gm weight and 180 * 180 mm size with 5 mm thickness were fabricated; this is agreement with [11]. component percentage% sio2 47.14 al2o3 34.74 fe2o3 1.26 tio2 1.2 cao >1 mg 0.25 so3 0.o7 moisture 14.44 http://www.iasj.net/ effect of kaolinite on the mechanical properties, thermal properties, flammability and water absorption percentage of poly (vinyl chloride) composite 30 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net fig. 1: hydraulic press equipment measurements 1. mechanical properties  tensile strength and elongation at break mechanical properties of the polymer blends films were measured on a shimadzu autograph in air at room temperature. tensile strength and elongation at break point were measured using a universal testing machine (tension_ compression to 5kn; manufactured by tinius olsen (uk). the compressed sheets were cut into dumbbell-shaped specimens according to astm d647-68.  hardness the hardness of all specimens was read and recorded; using a vickers diamond indenter (digital micro hardness tester), hvs– 1000.vickers indentation is a valid tool for evaluating the hardness of polymers .with a load of 0.4403 n. the load is applied for time 20 s (astm standard “test method for vickers hardness”, 1997). for every specimen, three readings were taken in accordance with polymeric matrix composite (pvc) astm-02240-97 for hardness test. the hardness value was determined by the penetration of the durometer indenter foot into the specimen. the sample was placed on a flat surface on the pressure foot of the instrument. a calibrated spring in the durometer applies a specific pressure to an indenter foot parallel to the surface of the surface of the specimen.  impact strength impact test sample specimens where fabricated by the standard specification [astm-e23] and which is appropriate for testing by the impact device type charpy (produced by (tokyo koki seizosho, ltd) company). the depth of the groove in the samples is 5mm with the groove base radius of 25 mm and a groove angle 45 0 . for the purpose of identifying the extent of impact strength which the composite material is capable of withstanding. from the equation 1 we see that the impact strength value is calculated: impact strength = …(1)  water absorption of the composites samples water absorption test was performed according to astm d570-99 (standard test method for water absorption of plastics, 1998) by conditioning and weighing the sample. each sample was immersed in distilled water in a transparent thermoplastic container and covered with the lid for 24 hr at 27 0 c. excess water on the sample surface was wiped off with a filter paper before reweighing turu et al. [1]. from equation 2 we see that the percentage increase in mass during immersion was calculated using the equation: % water absorption = [(wet weight dry weight)/ dry weight] * 100 …(2) http://www.iasj.net/ basma a. abdul majeed and dhilal amer sabar -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 31 wet weight: is the weight of sample after immersing in water for 24 h (g) dry weight: is the initial weight of sample (g). 2. thermal properties  differential scanning calorimeter (dsc) the thermal properties of the composites were determined by differential scanning calorimeter dsc measurements performed using a shimadzu dsc-50, japan, at a heating rate of 10 o c/min in the temperature range (25-250) 0 c under nitrogen purge. the glass transition temperature was taken as the midpoint of the transition.  conductivity measurement (k,  and cp) thermal conductivity measurements were done using setaram, instrumentation, kep technologiestherm tci tm , and thermal conductivity analyzer/made in france. the mathis tci is based on the modified transient plane source technique. it uses a one-sided, interfacial, heat reflectance sensor that applies a momentary, constant heat source to the sample. both thermal conductivity and effusivity are measured directly and rapidly, providing a detailed overview of the thermal characteristics of the sample material. sample material can be a solid, liquid, paste or powder [12, 13]. from the equation 3 we see that the heat capacity values of polymer composite [14]: the effusivity equation by (ws½ / m2 .k) =√ …(3) 3. flammability  burning speed measurement test [to measure the time required for burning until a full self-extinguish take place using (astm: d_635)] this method is considered as an internationally adopted one and is used to measure the flame dispersing speed in the different polymer material and to calculate the time duration needed for the burning. it is vastly used in polymer material convertible into plates, sheets or bars. polymers test able in this method are categorized to be flammable and self-extinguishable after a certain time of burning according to astm: d_635.  flame height measuring using the test (astm: d-3014) this test is one of the lab methods used to measure the flame height a burning polymer can make. it is vastly used in polymer material convertible in to plates, sheets or bars. results and discussion from the data presented in table 3, figure 2 and 3 it can be seen that the increase in filler content causes a decrease in tensile strength which can be attributed to the decrease in the interfacial forces between pvc crosslinks across the interface and the filler particles. also, a decrease in elongation at break is noticed. this may be due to the fact that the molecules of the fillers can distribute in the inter-aggregate space by an inter-structural process according to dimitry et al. [15]. likewise, the decrease in tensile strength and elongation at break with increasing filler content can also be attributed to the weak points in the material caused by the aggregates. these can break very easily by the applied stress .when broken, the aggregates concentrate the stress strongly thus decreasing the tensile strength of kaolin. this is in http://www.iasj.net/ effect of kaolinite on the mechanical properties, thermal properties, flammability and water absorption percentage of poly (vinyl chloride) composite 32 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net agreement of the results of leong et al. [16]. table 3 gives the test results for the hardness values for the basic pvc material reinforced with kaolin and figure 4; the results show a significant improvement in the values of hardness for the different content of reinforcement. the 12% content showed the best hardness values, this is agreement with [4]. table 3: mechanical properties of unfilled pvc, pvc-kaolinite composites sample designation tensile strength (mpa) elongation% shore a hardness impact strength (kj/m 2 ) pvc neat 2.615 45.6 8.7 4.57 pvc-3% kaolin 1.499 4.613 16.5 9.472 pvc-7% kaolin 1.259 2.533 17.6 6.06 pvc-12%kaolin 0.907 0.567 30 4.12 fig. 2: tensile strength curve of pvc /kaolinite composite fig. 3: elongation curve of pvc/kaolinite composite fig. 4: hardness (shore a) of unfilled pvc and pvc/ kaolinite composite 0 0.5 1 1.5 2 2.5 3 0 5 10 15 t e n si le s tr e n g th ( m p a ) wt% increase in filler content toughness pvc/kaolin… 0 10 20 30 40 50 0 5 10 15 e lo n g a ti o n % wt% increase in filler content strain pvc/kaolin… 0 10 20 30 40 0 5 10 15 h a rd n e ss v a lu e wt% increase in filler content hardness pvc/kaolin… http://www.iasj.net/ basma a. abdul majeed and dhilal amer sabar -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 33 table 3 and figure 5 illustrate how the impact strength value changes with the change of the content added of kaolinite. despite the good dispersion of the filler, the lack of kaolin adhesion to the matrix can lead to the impact strength values. when the loading of kaolin is high, its surface energy will be high causing severe agglomerates of filler .this can initiate many cracks and many stressed sites, which are susceptible to stress impacts, causing damaging effects on the impact properties of the composite [16]. when the kaolin is added to the pvc with a weight content of 3%wt and 7%wt, an increase on the water absorbability of the pvc occurs in figure 7, table 4. this behavior might be due to the presence of void spaces in the matrix which could have been formed during compounding of composites. the void spaces in the matrix accommodates the water absorbed [1]. kaolinite which is hydrophilic which is inorganic materials have the effect of absorbing water particles which contributes to the increase of samples ' weight. when 12%wt clay content is added a relative drop on the absorbability is noticed compared with the other content. this is attributed to the fact that the increases on kaolin content have the effect of filling the free interspaces between polymer chains which reduces the penetration of water particles through those chains. this proves that using this particular content reduces the water absorbability of the pvc retaining at the same time the improvement of mechanical properties such as hardness. fig. 5: impact strength curve of unfilled pvc and pvc/ kaolinite composites table 4: water absorption percentage results for pvc/ kaolin composite for 5 day fig. 6: plots water content against percentage increase in filler (after 24 h of immersion at 25 0 c) 0 5 10 0 5 10 15 im p a ct s tr e n g th (k j/ m 2 ) wt% increase in filler content impact strength pvc/kaolin… 0 1 2 3 0 5 10 15 w a te r a b so rp ti o n w t% wt% increase in filler content water absorption wt% pvc/kaolin… % kaolin % water uptake(after 24 h of immersion at 25 0 c) %day1 %day2 %day3 %day4 %day5 0 0.722 1.08 1.805 4.33 5.05 3 1.68 2.70 3.71 6.75 8.10 7 2.08 2.68 3.88 7.16 8.05 12 1.15 1.38 1.48 2.07 2.53 http://www.iasj.net/ effect of kaolinite on the mechanical properties, thermal properties, flammability and water absorption percentage of poly (vinyl chloride) composite 34 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net fig. 7: water absorption percentage of unfilled pvc, pvc/kaolin composite versus time based on the data collected from the dsc thermo-gram table 5 and figure 8, 9 and the glass transition temperature were found out. whereas the fillers fill and the gaps or spaces between the polymers chain, they restrict the chains movement and improve their plastic properties. the results showed t3%, t7% and t12% shifted toward higher temperatures for kaolinite compared to neat pvc. this is agreement with [17, 18]. table 5: thermal properties of unfilled pvc, pvc-kaolinite composites sample designation glass transition temp. (tg) ( 0 c) thermal conductivity value (k) (w/m. k) effusivity() (ws ½ / m 2 .k) heat capacity results cp (j/g.k) pvc neat 89.09 0.222 580.4 1083 pvc-3% kaolinite 98.70 0.240 601.1 1052 pvc-7% kaolinite 100.47 0.291 657.5 1010 pvc-12% kaolinite 103.37 0.437 812.3 986.8 fig. 8: plots glass transition temperature against percentage increase in filler as the content of the kaolinite filler increases so does the thermal conductivity figure 10, accompanied by the increase of thermal effusivity figure 11, and a decrease in heat capacity figure 12, this is agreement with [14]. the results of the measurement showed a large increase in the burning time and showed large decrease in the rate of burning for pvc/kaolinite composite, with other words the higher the kaolin content the higher burning time and the lower rate of burning which are evident in figures 13 and 14, table 6 , this is agreement with [19]. the results of the measurement showed decrease in the flame height (h) for pvc/kaolinite composite. this decrease in the flame height (h) is inversely proportional with the increase of the kaolinite content to the neat pvc with other words the higher 0 2 4 6 8 10 0 1 2 3 4 5 6 w a te r a b so rp ti o n w t% time, days unfilled pvc 3% kaolin 7%kaolin 12% kaolin 85 90 95 100 105 0 5 10 15g la ss t ra n si ti o n t e m p . 0 c wt% increase in filler content dsc pvc/kaolin… http://www.iasj.net/ basma a. abdul majeed and dhilal amer sabar -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 35 the filler content the lower rate of the flame height (h) which is evident in figure 14 and table 6, this is agreement with [20]. neat pvc pvc/3% kaolin 7% kaolin /pvc 12% kaolin /pvc fig. 9: dsc results for pvc/kaolinite composites fig. 10: thermal conductivity against filler content fig. 11: effusivity against filler content 0 0.1 0.2 0.3 0.4 0.5 0 5 10 15 t h e rm a l co n d u ct iv it y v a lu e w /m . k wt% increase in filler content thermal conductivity pvc/kaolin… 0 200 400 600 800 1000 0 5 10 15 e ff u si v it y v a lu e wt% increase in filler content effusivity pvc/kaolin… http://www.iasj.net/ effect of kaolinite on the mechanical properties, thermal properties, flammability and water absorption percentage of poly (vinyl chloride) composite 36 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net fig. 12: heat capacity against filler content table 6: flammability properties of unfilled pvc, pvc-bentonite composites and pvc-organoclay composites sample designation burning time (min) rate of burning (cm/s) height of flame (mm) pvc neat 6 0.027 50 pvc-3% kaolinite 11 0.015 18 pvc-7% kaolinite 14 0.011 15 pvc-12% kaolinite 20 0.0083 12.5 fig. 13: the burning time against filler content fig. 14: rate of burning against filler content fig. 15: flame height against filler content 950 1000 1050 1100 0 5 10 15h e a t ca p a ci ty j/ g . k wt% increase in filler content heat capacity pvc/kaolin… 0 5 10 15 0 5 10 15 ti m e , m in wt% increase in filler content burning time (min) pvc/kaolin composite 0 0.01 0.02 0.03 0 5 10 15 r a te o f b u rn in g (c m /s ) wt% increase in filler content rate of burning pvc/kaolin composite 0 20 40 60 0 5 10 15 h e ig h t (m m ) wt% increase in filler content height of flame pvc/kaolin composite http://www.iasj.net/ basma a. abdul majeed and dhilal amer sabar -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 37 conclusion by analyzing the results obtained in this work, the following conclusions can be drawn: 1. increasing the kaolinite loading causes a decrease in tensile strength which can be attributed to the decrease in the interfacial forces between pvc crosslinks across the interface and the filler particles. also, a decrease in elongation at break is noticed. this may be due to that the molecules of the fillers can distribute in the inter-aggregate space by an inter-structural process. 2. the results showed a significant improvement on the values of hardness for the different content of reinforcements. the 12% content showed the best hardness values. 3. it is noticed that the impact strength value of the kaolin at the beginning increase the impact resistance at lower kaolin loadings. this is due to the lack of kaolin adhesion to the matrix, although there is good dispersion of the filler. however, at higher kaolin loadings, severe agglomeration of the filler due to its high surface energy creates many crack-initiation and stressconcentration sites, which are very sensitive to impact stresses and cause detrimental effects on the impact properties of the composite. 4. when 12%wt clay content is added a relative drop in the absorbability is noticed compared with the other content. this is attributed to the fact that the increase in kaolin content has the effect of filling the free interspaces between polymer chains which reduces the penetration of water particles through those chains. this proves that using this particular content reduces the water absorbability of the pvc. 5. the results showed t3%, t7% and t12% (tg) shifted toward higher temperatures for kaolinite compared to neat pvc. 6. thermal conductivity values and effusivity increased with increasing filler loading .heat capacity decreased with increasing filler content. 7. the higher the filler content the higher burning time, the lower rate of burning and the lower height of the flame which are evident at 12wt%. references 1. turu, e.m., kolawole, e. g., gimba, c. e., dallatu, y.a. and yerima y., (2014), "effect of fired clay on the physical and mechanical properties of unplasticized poly (vinyl chloride) composite", the international journal of engineering and science (ijes), vol. 3, pp. 20-28. 2. zýková, j., kalendova, a., matejka, v., zadrapa, p. and malac, j., (2010), "kaolinite-urea intercalates for pvc nanocomposites", 5 (october 2015), pp. 10–14. 3. hashim, f.s., (2012), "enhancement of mechanical properties for reinforced iraqi bentonite clay polyvinyl chloride composite using ultrasonic technique", chemistry and materials research, no. 6, vol. 2, pp. 24–32. 4. a.m. motawie, a.a.khalil, a.i.a. eid, k.m. el-ashry, e.m.s., (2014), "some studies on poly (vinyl chloride)/layered silicate nanocomposites part 1, morphology, physico-mechanical, and thermal properties", journal of applied sciences research, no. 12, vol. 9, pp. 6355–6364. 5. savrik, s. a., b. c. erdogan, d. balkose and s. ulku, (2010), "statistical thermal stability of pvc", journal of applied polymer http://www.iasj.net/ effect of kaolinite on the mechanical properties, thermal properties, flammability and water absorption percentage of poly (vinyl chloride) composite 38 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net science, no. 3, vol. 116, pp. 18111822. 6. turhan, y., dog, m. & alkan, m., (2010), "poly (vinyl chloride)/ kaolinite nanocomposites : characterization and thermal and optical properties", industrial & engineering chemistry research, vol. 49, pp. 1503–1513. 7. zýková, j., kalendova, a., matejka, v., zadrapa, p. and malac, j., (2015), "influence of kaolinite modification on the pvc composites properties", methods, pp. 30–34. 8. wilkes, c.e., summers, j.w., daniels, c.a. and bernard, m.t., (2005), "pvc handbook", hanser verlag, pp. 176-181. 9. pasdar, m.d. and h., (2012), "the influence of a variety of plasticisers on properties of poly (vinyl chloride)", pelagia research library advances in applied science research, no. 4, vol. 3, pp. 1900– 1904. 10. bonadies, i., avella, m., avolio, r., carfagna, c., errico, m. and gentile, g. (2011), "poly (vinyl chloride)/caco3 nanocomposites: influence of surface treatments on the properties", journal of applied polymer science, no. 6, vol. 122, pp. 3590-3598. 11. deshmukh, s.p. and rao, a c., (2012), "mica filled pvc composites : performance enhancement in dielectric and mechanical properties with treated / untreated mica of different particle size and different concentration", no. 2, vol. 11, pp. 169–181. 12. mateusz b., (2007), "carbon nan tube networks in epoxy composites and aero gels", phd. thesis, university of pennsylvania. 13. selvaraj, d. edison, (2012), "partial discharge characteristics of enamel filled with micro and no composite of sio2 and tio2", international journal of science and engineering applications 1.2, pp. 95-101. 14. fadhil, k. f., (2015), "empirical and simulation investigations of tribological and thermal characteristics of polymer nano composites", phd. thesis, science of college, al-mustansiriyah university. 15. dimitry, o.i.h., sayed, w. m., mazroua, a. m. and saad, a. l. g., (2009), "poly (vinyl chloride)/ nanoclay nanocomposites — electrical and mechanical properties", no. 1, vol. 54, pp. 8– 14. 16. leong, y.w., abu bakar, m. b., mohd. ishak, z. a.,ariffin, a. and pukanszky, b., (2004), "comparison of the mechanical properties and interfacial interactions between talc, kaolin, and calcium carbonate filled polypropylene composites", journal of applied polymer science, no. 5, vol. 91, pp. 3315–3326. 17. karakus, s., budinski-simendic, j., korugic-karasz, l. and z. aroguz, a., (2010), "characterization of poly (vinyl chloride) /bentonite nanocomposite prepared via melt blending method", in: ljiljana korugickarasz. ed. contemporary science of polymeric materials. washington, dc: american chemical society. chapter 8, pp 103-113. 18. hai liu, lijie dong, haian xie and chuanxi xiong, (2012),"novelmodified kaolin for enhancing the mechanical and thermal properties of poly (vinyl chloride)", polymer engineering and science, no. 10, vol. 52. 19. faris a.h., (2003), "study the effect of using some inorganic and http://www.iasj.net/ basma a. abdul majeed and dhilal amer sabar -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 39 halogenated additives for the flame retardant additives and increase the fire resistance of epoxy resin", m.sc. thesis, alrashed college, technology university. 20. beyer g., (2008), "organoclays as flame retardants for pvc", polymers for advanced technologies, vol. 19, pp. 485–488. http://www.iasj.net/ available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.20 no.2 (june 2019) 11 – 15 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: basma i. waisi , email: basmawaisi@gmail.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. carbonized copolymers nonwoven nanofibers composite: surface morphology and fibers orientation basma i. waisi department of chemical engineering, college of engineering, university of baghdad, baghdad, iraq abstract carbonized nonwoven nanofibers composite were fabricated using the electrospinning method of a polymeric solution composite followed by heat treatment including stabilization and calcination steps. the spun polymeric solution was a binary polymer mixture/organic solvent. in this study, two types of polymers (polymethylmethacrylate (pmma) and polyethylene glycol (peg)) were used separately as a copolymer with the base polymer (polyacrylonitrile (pan)) to prepare a binary polymer mixture in a mixing ratio of 50:50. the prepared precursor solutions were used to prepare the precursor nanofibers composite (pan: pmma) and (pan: peg). the fabricated precursors nonwoven fibers composite were stabilized and carbonized to produce carbon nonwoven nanofibers composite. the effect of the combined polymer type on the fiber size, fiber size distribution, and surface morphology of the prepared nonwoven nanofibers was studied. the nonwoven fibers orientation and surface morphology were characterized using field emission scanning electron microscope (fesem). in addition, imagej software has been used to calculate the fiber size and fiber size distribution. here, the obvious effect of the copolymer type on the surface morphology, fiber size, and fiber orientation has been demonstrated. using a copolymer with pan polymer led to increasing the fiber size. the carbonized nanofibers composite prepared using peg polymer as a copolymer was more ordered fibers in comparison with the fiber orientation of carbon nanofibers based on pure pan. in contrast of that, using pmma as a copolymer resulted curly carbonized nonwoven nanofiber composite. keywords: copolymers, nanofibers, orientation, surface morphology, fiber received on 18/03/2019, accepted on 20/04/2019, published on 30/06/1029 https://doi.org/10.31699/ijcpe.2019.2.2 1introduction polymeric membranes have wide applications in various fields including water treatment ‎[1],‎[2]. recently, electrospinning technique has been widely used to fabricate nonwoven polymeric nanofiber membranes using an electrically forced fluid jet ‎[3], ‎[4]. the electrospun nanofiber membranes are considered good candidates for many applications, specifically, water filtration due to high permeability, high porosity, fully interconnected pore structures, low hydraulic resistance, and tunable wettability ‎[5], ‎[6]. in addition, polymeric membranes, based on specific types of polymers, can be converted into carbon nonwoven nanofibers through postthermal treatment steps including stabilization and carbonization steps ‎[7], ‎[8]. carbon nanofibers are considered as one of the typical one-dimensional nanomaterials and they are commonly fabricated using polyacrylonitrile (pan) as a precursor due to the high carbon yield, high melting point, and low cost of this type of polymer ‎[9]. this type of carbon material has unique features such as high specific area, high permeability, high aspect ratio, good conductivity and mechanical properties ‎[5], ‎[6], ‎[8], ‎[10]. there are several applications for carbon fibers such as energy storage in lithium-ion batteries, sensors, fuel cells, and catalysts ‎[7], ‎[9], ‎[11],‎[12]. the precursor solution properties have a significant effect on surface morphology of electrospun fibers ‎[13]. the surface morphology and fibers properties of electrospun nonwoven fibers can be tuned through various approaches including embedding nanoparticles ‎[14],‎[15], using some chemicals to impart functionalities ‎[16], ‎[17], and using combined polymers ‎[18]. the combined polymers can have a significant effect on the fabricated spanned fibers according to the introduced polymer properties ‎[19]. for an instance, a novel anode material in rechargeable lithium-ion batteries (lib) was made using modified carbon nanofibers based on copolymer precursor (polyacrylonitrile (pan): polypyrrole (ppy)/ dimethylformamide (dmf) solvent) [18]. the copolymer ppy was used as a conductive polymer to improve the conductivity of the fabricated carbon fibers composite. this study is mainly concerned with fabrication electrospun carbon nonwoven nanofibers using pure pan/dmf, composite (pan: pmma)/dmf, and composite (pan: peg)/dmf using a copolymer mixing ratio of 50:50. the obtained results of the composite carbon nonwoven nanofiber membranes have been compared with carbon nanofiber based on pure pan to investigate the effect of the copolymer type on the surface morphology of the fabricated carbon membrane. https://doi.org/10.31699/ijcpe.2019.2.2 b. i. waisi / iraqi journal of chemical and petroleum engineering 20,2 (2019) 11 15 21 scanning electron microscopy (sem) and imagej software have been used to study the surface and fibers characterization. 2materials and methods 2.1. preparation of carbonized nonwoven nanofibers polyacrylonitrile (pan) (mwt. 150,000 g.mol -1 ), polyethylene glycol (peg) (mwt. 20,000 g.mol -1 ), and polymethylmethacrylate (pmma) (mwt. 996,000 g.mol 1 ) were purchased from sigma-aldrich. dimethylformamide (dmf) solvent was provided by fisher as an appropriate solvent for the used polymers. the base polymer was pan, while pmma and peg were the copolymer with pan to prepare the composite nonwoven. the blend ratio of base polymer (pan)/copolymer (peg or pmma) was 50:50 weight ratio in dmf and the final polymer concentration was kept constant as 12 wt. %. the precursor solutions were prepared by constant stirring for 12 hr at 50 ℃. the precursor solution was then fed through a 20 gauge end needle using a syringe (30 ml) to be dispensed onto a collector rotating at 70 rpm using a syringe pump (kd scientific) as shown in fig. 1. during electrospinning, the flow rate of the charged solution (pure pan, pan: pmma and pan: peg) was constant at 1ml/hr and the applied voltage was 15, 18, and 21 kv, respectively. then, the fabricated precursor nonwoven fibers was stabilized in a muffle furnace (carbolite) at 270 °c for 1 h in air atmosphere followed by carbonization in a tube furnace (lindberg blue m, thermo scientific) at 650 o c for 1 hr in a nitrogen atmosphere. fig. 1. schematic diagram of the electrospinning machine 2.2. fabricated nonwovens characterizations to explore the possible changes in nonwoven fibers structure and surface morphology, the carbonized nonwovens were analyzed using a jsm-5610 scanning electron microscope (sem, japan) after coating with platinum to minimize the charging effect. in addition, the average fiber diameter and fiber size distribution were characterized using imagej software (national institutes of health). 3results and discussion 3.1. nanofibers morphology during electrospinning, the molecular chains in the precursor nanofibers collected on the rotating drum and relax to some extent resulting in a certain orientation depending on the used precursor polymer properties. after carbonization step, many structural imperfections in the precursor fibers are likely to be retained carbon fibers. fig. 2 shows the sem image of the carbonized nonwoven fibers based on pure pan, the fibers have curvature structure with presence of some beads within the mat structure. the sem images presented in fig. 3 a and b are for the carbonized nonwoven fibers composite based on pan: pmma and pan: peg with a mixing ratio of 50:50. regarding to the precursor polymer type, introducing the copolymer with pan resulted in an obvious change in the nonwoven structure and fibers size of the fabricated carbonized composite mats. according to the precursor solution recipe, the overall surface morphology was changes comparing to the carbonized nanofibers based on pure pan. the fibers of the carbonized nonwoven composite based on pan: pmma were spaghetti-like fibers and with some stacked fibers with each other. while the carbonized composite fibers based on pan: peg were straight and structurally ordered fibers. this can be explained by the difference in glass transition (tg) and melting temperatures (tm) for the used polymers (pan, pmma, and peg) as listed in table 1. during the carbonization step, pan pyrolyzed to carbon while pmma and peg were thermally degraded to small molecules or even evaporated due to the low glass and melting temperatures comparing with those of pan. some intermolecular interactions between pan and the copolymer phases occurred in the composite precursor nanofibers, which influenced the stabilization and carbonization of nonwoven composite precursor. in addition, the loss of macromolecular orientation in final carbonized nanofibers composite may be the reason behind inferior fibers properties of the resulting carbon nanofibers composite. table 1. the glass transition and melting temperatures for the used polymers ‎[20] polymer type glass transition temperature tg ( o c) melting temperature tm ( o c) polyacrylonitrile (pan) 109 321 polymethylmethacrylate (pmma) 105 144 polyethylene glycol (peg) -67 66 b. i. waisi / iraqi journal of chemical and petroleum engineering 20,2 (2019) 11 15 21 fig. 2. the sem images of carbonized 12 % pan/dmf nonwoven nanofibers fig. 3. the sem images of carbonized nonwoven nanofiber composite: (a) (pan: pmma)/dmf and (b) (pan: peg)/dmf 3.2. nanofibers size distribution fig. 4 shows carbon nanofiber based on 12% pan/dmf has nanosized fibers with 140 nm average fiber diameter which lays within the range of 80 200 nm. introducing a copolymer with pan resulted larger fiber size of the carbonized nonwoven nanofibers composite: 170 nm for (pan: pmma) and to 260 nm for (pan: peg) as shown in fig. 5 a and b. most of the fibers of pan: pmma was in the size range of 140-220 nm, while the fiber size of pan: peg nonwoven was distributed almost equally between 200-320 nm. increasing the average fiber size can be likely attributed to increasing the precursor solution viscosity (cp) resulted from introducing the copolymer. for the same total polymer concentration in the prepared precursor solutions, the lowest viscosity amongst the various precursors was for pure pan, while pan: peg had the largest viscosity. increasing the solution viscosity decreased the extension during spinning because chain entanglements become more flexible chain resulting thicker fibers ‎[21]. fig. 4. average fiber size and distribution of the fabricated carbon nonwoven based on 12% pan/dmf fig. 5. average fiber size and distribution of the fabricated carbon composite nonwoven nanofiber (a) (pan: pmma) /dmf(b) (pan: peg)/dmf b. i. waisi / iraqi journal of chemical and petroleum engineering 20,2 (2019) 11 15 21 4conclusions the surface morphology is a very important property to control the porosity of the required nonwoven membrane for various applications. carbon nanofiber can be prepared with different surface morphology when it is prepared from different precursor polymer solutions using various types of copolymers. the nonwovens structure of the carbonized mats based on pure pan contained bend nanofibers with some beads. introducing a copolymer with pan produced larger fiber size with different surface morphology due to the difference in the glass and melting temperatures. using pmma as a copolymer resulted in spaghetti-like nonwoven fibers while using peg resulted in large fiber size with a straight structure. references [1] a.h. algureiri, y.r. abdulmajeed, removal of heavy metals from industrial wastewater by using ro membrane, iraqi j. chem. pet. eng. 17 (2016) 125– 136. [2] t.k. hussein, comparative study for removal of zn + 2 ions from aqueous solutions by adsorption and forward osmosis, iraqi j. chem. pet. eng. 18 (2017) 125–138. [3] a. raza, j. wang, s. yang, y. si, b. ding, hierarchical porous carbon nanofibers via electrospinning, carbon lett. 15 (2014) 1–14. [4] i.s. chronakis, novel nanocomposites and nanoceramics based on polymer nanofibers using electrospinning process — a review, j. mater. process. technol. 167 (2005) 283–293. [5] x. wang, b. ding, j. yu, m. wang, engineering biomimetic superhydrophobic surfaces of electrospun nanomaterials, mater. today. 6 (2011) 510–530. [6] x. wang, j. yu, g. sun, b. ding, electrospun nanofibrous materials: a versatile medium for effective oil/water separation, mater. today. 00 (2015) 0–11. [7] l. zhang, a. aboagye, a. kelkar, c. lai, h. fong, a review: carbon nanofibers from electrospun polyacrylonitrile and their applications, j. mater. sci. 49 (2014) 463–480. [8] b.i. waisi, s.s. manickam, n.e. benes, a. nijmeijer, j.r. mccutcheon, activated carbon nanofiber nonwovens: improving strength and surface area by tuning the fabrication procedure, ind. eng. chem. res. 58 (2019) 4084–4089. [9] s.s. manickam, u. karra, l. huang, n. bui, b. li, j.r. mccutcheon, activated carbon nanofiber anodes for microbial fuel cells, carbon n. y. 53 (2013) 19– 28. [10] k. dincer, b. waisi, g. önal, n. tu, j. mccutcheon, ö.f. yüksel, investigation of optical and dispersion parameters of electrospinning grown activated carbon nano fiber ( acnf ) layer, synth. met. 237 (2018) 16–22. [11] c. chen, r. agrawal, y. hao, c. wang, activated carbon nanofibers as high capacity anodes for lithium-ion batteries, ecs j. solid state sci. technol. 2 (2013) m3074–m3077. [12] u. karra, s.s. manickam, j.r. mccutcheon, n. patel, b. li, power generation and organics removal from wastewater using activated carbon nanofiber (acnf) microbial fuel cells (mfcs), int. j. hydrogen energy. 38 (2013) 1588–1597. [13] l. huang, n.n. bui, s.s. manickam, j.r. mccutcheon, controlling electrospun nanofiber morphology and mechanical properties using humidity, j. polym. sci. part b polym. phys. 49 (2011) 1734–1744. [14] n.a.m. barakat, m.f. abadir, f.a. sheikh, m.a. kanjwal, s.j. park, h.y. kim, polymeric nanofibers containing solid nanoparticles prepared by electrospinning and their applications, chem. eng. j. 156 (2010) 487–495. [15] b.i. waisi, s.m. al-jubouri, r. mccutcheon, fabrication and characterizations of silica nanoparticle embedded carbon nano fibers, ind. eng. chem. res. 58 (2019) 4462–4467. [16] k.l. klein, a.v. melechko, m. t. e., s.t. retterer, p.d. rack, j.d. fowlkes, et al., surface characterization and functionalization of carbon nanofibers, j. appl. phys. 103 (2008). [17] x. wang, j. wang, y. si, b. ding, j. yu, g. sun, et al., nanofiber-net-binary structured membranes for highly sensitive detection of trace hcl gas, nanoscale. 4 (2012) 7585–7592. [18] l. ji, y. yao, o. toprakci, z. lin, y. liang, q. shi, et al., fabrication of carbon nanofiber-driven electrodes from electrospun polyacrylonitrile / polypyrrole bicomponents for high-performance rechargeable lithium-ion batteries, j. power sources. 195 (2010) 2050–2056. [19] c.-t. wang, c.-c. kuo, h.-c. chen, w.-c. chen, non-woven and aligned electrospun multicomponent luminescent polymer nanofibers : effects of aggregated morphology on the photophysical properties, nanotechnology. 20 (2009) 1–10. [20] http://polymerdatabase.com/class%20index.html , polymer properties database, (2019). [21] m. faccini, g. borja, m. boerrigter, d.m. martin, s.m. crespiera, s. vazquez-campos, et al., electrospun carbon nanofiber membranes for filtration of nanoparticles from water, j. nanomater. (2015) 1–9. https://www.iasj.net/iasj?func=fulltext&aid=116449. https://www.iasj.net/iasj?func=fulltext&aid=116449. https://www.iasj.net/iasj?func=fulltext&aid=116449. https://www.iasj.net/iasj?func=fulltext&aid=116449. https://www.iasj.net/iasj?func=article&aid=127806. https://www.iasj.net/iasj?func=article&aid=127806. https://www.iasj.net/iasj?func=article&aid=127806. https://www.iasj.net/iasj?func=article&aid=127806. http://koreascience.or.kr/journal/view.jsp?kj=hgtsb6&py=2014&vnc=v15n1&sp=1. http://koreascience.or.kr/journal/view.jsp?kj=hgtsb6&py=2014&vnc=v15n1&sp=1. http://koreascience.or.kr/journal/view.jsp?kj=hgtsb6&py=2014&vnc=v15n1&sp=1. https://www.sciencedirect.com/science/article/pii/s0924013605006114. https://www.sciencedirect.com/science/article/pii/s0924013605006114. https://www.sciencedirect.com/science/article/pii/s0924013605006114. https://www.sciencedirect.com/science/article/pii/s0924013605006114. https://www.sciencedirect.com/science/article/pii/s1748013211000934. https://www.sciencedirect.com/science/article/pii/s1748013211000934. https://www.sciencedirect.com/science/article/pii/s1748013211000934. http://linkinghub.elsevier.com/retrieve/pii/s1369702115003855. http://linkinghub.elsevier.com/retrieve/pii/s1369702115003855. http://linkinghub.elsevier.com/retrieve/pii/s1369702115003855. http://linkinghub.elsevier.com/retrieve/pii/s1369702115003855. https://link.springer.com/article/10.1007/s10853-013-7705-y. https://link.springer.com/article/10.1007/s10853-013-7705-y. https://link.springer.com/article/10.1007/s10853-013-7705-y. https://link.springer.com/article/10.1007/s10853-013-7705-y. https://pubs.acs.org/doi/10.1021/acs.iecr.8b05612. https://pubs.acs.org/doi/10.1021/acs.iecr.8b05612. https://pubs.acs.org/doi/10.1021/acs.iecr.8b05612. https://pubs.acs.org/doi/10.1021/acs.iecr.8b05612. https://pubs.acs.org/doi/10.1021/acs.iecr.8b05612. http://dx.doi.org/10.1016/j.carbon.2012.10.009. http://dx.doi.org/10.1016/j.carbon.2012.10.009. http://dx.doi.org/10.1016/j.carbon.2012.10.009. http://dx.doi.org/10.1016/j.carbon.2012.10.009. https://www.sciencedirect.com/science/article/abs/pii/s0379677918300158. https://www.sciencedirect.com/science/article/abs/pii/s0379677918300158. https://www.sciencedirect.com/science/article/abs/pii/s0379677918300158. https://www.sciencedirect.com/science/article/abs/pii/s0379677918300158. https://www.sciencedirect.com/science/article/abs/pii/s0379677918300158. http://jss.ecsdl.org/content/2/10/m3074.abstract. http://jss.ecsdl.org/content/2/10/m3074.abstract. http://jss.ecsdl.org/content/2/10/m3074.abstract. http://jss.ecsdl.org/content/2/10/m3074.abstract. http://dx.doi.org/10.1016/j.ijhydene.2012.11.005. http://dx.doi.org/10.1016/j.ijhydene.2012.11.005. http://dx.doi.org/10.1016/j.ijhydene.2012.11.005. http://dx.doi.org/10.1016/j.ijhydene.2012.11.005. http://dx.doi.org/10.1016/j.ijhydene.2012.11.005. https://mccutcheon.lab.uconn.edu/wp-content/uploads/sites/1184/2015/05/huang-jps-b-49-2011-1734-1744.pdf. https://mccutcheon.lab.uconn.edu/wp-content/uploads/sites/1184/2015/05/huang-jps-b-49-2011-1734-1744.pdf. https://mccutcheon.lab.uconn.edu/wp-content/uploads/sites/1184/2015/05/huang-jps-b-49-2011-1734-1744.pdf. https://mccutcheon.lab.uconn.edu/wp-content/uploads/sites/1184/2015/05/huang-jps-b-49-2011-1734-1744.pdf. https://mccutcheon.lab.uconn.edu/wp-content/uploads/sites/1184/2015/05/huang-jps-b-49-2011-1734-1744.pdf. https://www.sciencedirect.com/science/article/pii/s1385894709008006. https://www.sciencedirect.com/science/article/pii/s1385894709008006. https://www.sciencedirect.com/science/article/pii/s1385894709008006. https://www.sciencedirect.com/science/article/pii/s1385894709008006. https://www.sciencedirect.com/science/article/pii/s1385894709008006. doi:10.1021/acs.iecr.8b05825. doi:10.1021/acs.iecr.8b05825. doi:10.1021/acs.iecr.8b05825. doi:10.1021/acs.iecr.8b05825. https://aip.scitation.org/doi/full/10.1063/1.2840049. https://aip.scitation.org/doi/full/10.1063/1.2840049. https://aip.scitation.org/doi/full/10.1063/1.2840049. https://aip.scitation.org/doi/full/10.1063/1.2840049. https://www.ncbi.nlm.nih.gov/pubmed/23108331. https://www.ncbi.nlm.nih.gov/pubmed/23108331. https://www.ncbi.nlm.nih.gov/pubmed/23108331. https://www.ncbi.nlm.nih.gov/pubmed/23108331. https://www.sciencedirect.com/science/article/abs/pii/s0378775309018230. https://www.sciencedirect.com/science/article/abs/pii/s0378775309018230. https://www.sciencedirect.com/science/article/abs/pii/s0378775309018230. https://www.sciencedirect.com/science/article/abs/pii/s0378775309018230. https://www.sciencedirect.com/science/article/abs/pii/s0378775309018230. https://www.sciencedirect.com/science/article/abs/pii/s0378775309018230. https://www.ncbi.nlm.nih.gov/pubmed/19706951. https://www.ncbi.nlm.nih.gov/pubmed/19706951. https://www.ncbi.nlm.nih.gov/pubmed/19706951. https://www.ncbi.nlm.nih.gov/pubmed/19706951. https://www.ncbi.nlm.nih.gov/pubmed/19706951. https://www.ncbi.nlm.nih.gov/pubmed/19706951. http://polymerdatabase.com/class%20index.html,%20polymer%20properties%20database,%20(2019). http://polymerdatabase.com/class%20index.html,%20polymer%20properties%20database,%20(2019). https://www.hindawi.com/journals/jnm/2015/247471/ https://www.hindawi.com/journals/jnm/2015/247471/ https://www.hindawi.com/journals/jnm/2015/247471/ https://www.hindawi.com/journals/jnm/2015/247471/ https://www.hindawi.com/journals/jnm/2015/247471/ b. i. waisi / iraqi journal of chemical and petroleum engineering 20,2 (2019) 11 15 21 المركبة: طبيعة السطح واتجاه االليافشبكة االلياف النانوية البوليميريو الكاربونية الخالصة تم تصنيع نسيج ألياف نانوية كاربونية باستخدام طريقة البثق الكيربائي لمركب المحمول البوليمري متبوًعا بالمعالجة الحرارية بما في ذلك عممية التثبيت والتكمس. كان المحمول البوليمري عبارة عن مزيج ثنائي البوليمر / polymethylmethacrylate (pmma)) مذيب عضوي. في ىذه الدراسة ، تم استخدام نوعين من البوليمرات بشكل منفصل كبوليمر ثانوي مع البوليمر األساسي (polyethylene glycol (peg) و (polyacrylonitrile (pan)) 00:00لتحضير خميط بوليمر ثنائي بنسبة خمط . و (pan: pmma)تم استخدام المحاليل التي تم تحضيرىا إلعداد ألياف نانويو بوليمرية مركبة (pan: peg) والتي تم تحويميا الى ألياف كاربونية مركبة بواسطة عمميو الكمسنة. تمت دراسة تأثير نوع لياف النانوية. تم دراسة اتجاىات البوليمر المشترك عمى حجم األلياف وتوزيع حجم األلياف وطبيعة السطح لأل باإلضافة إلى ذلك ، تم استخدام (fesem)األلياف وطبيعة السطح باستخدام المجير اإللكتروني الماسح لحساب حجم األلياف وتوزيع حجم األلياف. ىنا ، تم اكتشاف التأثير الواضح لنوع البوليمر imagej برنامج أللياف واتجاه األلياف. حيث أدى استخدام البوليمر الثانوي مع الثانوي عمى التشكل السطحي وحجم ا peg إلى زيادة حجم األلياف. كان ألياف األلياف النانوية الكربونية المحضرة باستخدام بوليمر البوليمراالساسي مالنقي. عمى النقيض من ذلك ، فإن استخدا pan أكثر ترتيًبا من األلياف الكاربونية المنتجة من بثق pmma كبوليمر ثانوي أدى إلى انتاج ألياف نانوية مركبة مجعدة. بوليمر ثانوي, الياف نانوية , اتجاه, طبيعة السطح , حجم االلياف. :دالة الكممات ال ijcpe vol.9 no. 2 (june 2008) iraqi journal of chemical and petroleum engineering vol.9 no.2 (june 2008) 69-74 issn: 1997-4884 biotreatment of oil wells drilling waste in an agricultural soil muna h. al-joubori * and ayad a. a. h. abd al-razaq * * department of biology, college of science, university of baghdad ** department of geology, college of science, university of baghdad abstract one of the most important environmental issues is the responsible effective and economic treatment of drilling waste especially oily waste. in this research two fungal isolates named pleurotus ostreatus and trichoderma harzianum were chosen for the first time to treat biologically the oily drilled cuttings contaminated with diesel which resulted from drilling oil wells use oil based muds (obms). the results showed that the fungi under study utilized the hydrocarbon of contaminated soil as a source of nutrient and growth and that both fungi can be considered hydrocarbon degrading microorganisms. the used biotreatment is cost effective process since most of the materials used in the cultivation and growth of the present fungi were available and cheap agricultural waste. the best hydrocarbon degradation was observed in case of using both fungi together with 8 % by weight microorganisms concentration ratio and with the same ratio of nutrients components expressed as carbon/nitrogen/phosphorus equal to 100/60/10 with 10/1 carbon/potassium which gave average total petroleum hydrocarbon degradation of about 395 ppm per day. good results were obtained using the new nutrients components ratio(c/n/p=100/60/10 with c/k=10) compared to other studies applied different nutrients ratios for the same type of diesel contamination. key words: oil wells, drilling waste, biotreatment, fungal introduction generally, drilling wastes include formation cuttings and drilling fluids with different kinds of chemical additives depending on the type of the drilling fluid that have been used. when oil-based or synthetic-base drilling fluids are used, the discharged cuttings typically have a hydrocarbon content of 10 to 15 % along with residual weighting material. these cuttings require specialized treatment prior to the appropriate disposal. in situations where the cuttings need to be treated, there are several possible options among of them cuttings re-injection, stabilization-solidification, landfill and bioremediation [1]. biotreatment is a well-proven environmentally acceptable technology that uses microorganisms to biologically degrade hydrocarbon waste into nontoxic university of baghdad college of engineering iraqi journal of chemical and petroleum engineering biotreatment of oil wells drilling waste in an agricultural soil 70 ijcpe vol.9 no. 2 (june 2008) residues and reduce contaminates concentrations to acceptable levels [2]. many microorganisms involving bacteria, fungi and yeasts have been isolated from soil contaminated with oil and studied for their ability of utilizing or producing hydrocarbons [3, 4, 5]. many studies proved that the most of the component in oils are prone to be degraded by microorganisms, as shown in table 1[6]. table 1 biodegradability of hydrocarbons in optimal conditions [6] microorganisms need nutrients for the buildup of their cellular biomass. the favorable nutrients conditions for hydrocarbons bioremediation are often expressed as c/n/p (carbon/nitrogen/phosphorous) ratio with recommended values 100/10/1 to 100/50/10 [7]. these values with c/k (carbon/potassium) equal to 17 allow an optimal microbial growth and biodegradation of hydrocarbons [8]. in this study, the selected fungi named pleurotus ostreatus (po) (white type) and trichoderma harizanum (th) are screened for their ability in hydrocarbon degradation of drill cuttings contaminated with diesel. moreover, these fungi have been used usefully in hydrocarbon degradation of drilled cuttings contaminated with crude oil [9].this biotreatment gave best average total petroleum hydrocarbon degradation of about 205 ppm/day in case of both fungi with 5% mcr and 5% ncr expressed as c/n/p=100/50/10.the production of different extra-cellular enzymes by fungus po have been reported by many studies [10-13], which expected to be capable of degrading diesel infested soil. similarly, the fungi th producing extra enzymes and examined for its activity in such degradation. the selected fungi can be utilized commercially for conversion of various agriculture products and wastes into fungal culture containing valuable protein. many agriculture byproducts like cereal, straw, rice hulls, reed residues and cattail residues are available in iraq with a dense association form occupy hundred square kilometers of land. pleurotus mushroom can directly grow on these agriculture wastes involves preferential lignin and cellulose degradation due to its enzymatic activity [9]. experimental work the selected drill cuttings are in the range of 40 to 60 percent by volume petroleum hydrocarbons in the diesel range (c12 to c18). the contaminated cuttings were crushed and mixed with soil at a ratio of 1:1 (weight by weight). the sample with total petroleum hydrocarbon concentration (tphc) equal to 19500 ppm was selected to be the base to measure the biodegradability of the present fungi. biotreatments of soil samples consisted of the following: 1. un-amended soil (waste + soil), 2. soil supplemented with fertilizers to provide a carbon/nitrogen phosphorous ratio of 100/60/10 with c/k=10, and 3. soil supplemented with fertilizers to provide a carbon/nitrogen/ phosphorus ratio of 35/10/1 with c/k=10. plastic containers with a capacity of 500 gm with eight replicates for each treatment were prepared to carry out the biotreatment processes. different concentrations of microorganisms weight ratio (mcr) were used which expressed as 6, 7 and 8 % (weight to dry weight of total mixture). two values of nutrients weight ratio (nwr) 6 % and 8 % (weight to dry weight of total mixture) are considered at cases of nutrients addition. each strain of fungi was processed with the above treatments as well as a combination of both. moisture was maintained at approximately 20 % and the temperature ranged from 20 to 40° c. fifty cm 3 grab samples were taken at time zero then at weekly crude and refined oils biodegradability (%) gasoline 100 jet fuel 90-100 naphtha, condensates 90-100 diesel oil 80-90 fuel oil 80-85 heavy fuel oil 10-50 crude oil 40-70 lubricating oil 30-75 muna h. al-joubori and ayad a. a. h. abd al-razaq 71 ijcpe vol.9 no. 2 (june 2008) intervals (0, 7, 14, 21, 28, 35, 42 and 49 days). samples were analyzed for their tphc using high performance liquid-chromatography (hplc type shimadzu lc-4a). fungi were grown on potato dextrose agar (pda) media and maintained in slants at 4° c [13]. preparation of inoculums and substrates had done according to many studies [9, 14] which confirmed an optimum processing condition of growth. results and discusion fig. 1 illustrates the result of biotreatment technology of un-amended soil. this figure shows that tphc decreased when mcr increased especially in the case of using both strains of fungi together. this noticeable degradation will be observed clearly with the rest treatments and the best hydrocarbon degradation was obtained with the combinations of both fungi strains at 8 % mcr which gave about 231 ppm per day. also, it was shown that the results of fungi th are relatively close to those of po. figs.2 and 3 show the effect of nutrients addition on the present biotreatment with the selected ncr (c/n/p=35/10/1 and 100/60/10) respectively and with 6 % nwr. these results demonstrated the necessity of nutrients for the bio-process. for example, at the case of combination of both stains with 8 % mcr, an average reduction in tphc of about 302 and 322 ppm per day was shown. this is a good result in comparison with a value of 231 ppm per day that obtained with the same conditions in the case of un-amended sample. fig. 1 average hydrocarbon degradation response to both fungi strains and ratios without nutrients fig. 2 average hydrocarbon degradation response to both fungi stains and ratios with 6 % nwr and c/n/p= 35/10/1, c/k=10 fig. 3 average hydrocarbon degradation response to both fungi strains and ratios with 6 % nwr and c/n/p= 100/60/10, c/k=10 microorganisms concentration ratio 6 % mcr 7 % mcr 8 % mcr a v e ra g e t p h c d e g ra d a ti o n , p p m /d a y 0 50 100 150 200 250 th po th+po microorganisms concentration ratio 6 % mcr 7 % mcr 8 % mcr a v e ra g e t p h c d e g ra d a ti o n , p p m /d a y 0 50 100 150 200 250 300 350 th po th+po microorganisms concentration ratio 6 % mcr 7 % mcr 8 % mcr a v e ra g e t p h c d e g ra d a ti o n , p p m /d a y 0 50 100 150 200 250 300 350 th po th+po biotreatment of oil wells drilling waste in an agricultural soil 72 ijcpe vol.9 no. 2 (june 2008) fig. 4 and 5 indicate the effect of another ratio equal to 8 % nwr. here, a significant increasing in whole degradation was shown, which explains how the increment in nwr will lead to progress in current biotreatment. the case of using both fungi together at 8 % mcr with 8 % nwr and c/n/p = 100/60/10 with c/k=10 illustrates the observed enhancement. moreover, it can be seen that tphc declined from 19500 ppm to less than 150 ppm during 49 days with less than 1000 ppm remaining after 30 days which appears to be a fairly typical exponential type degradation curve as shown in fig. 6. fig. 7 represents a relationship between tphc with time for selected values of mcr, nwr and nwc. the purpose of this figure is to show the significant difference in the microbial treatment between the unamended and the nutrient amended soils. according to these results with a limit of 10000 ppm as an example, the addition of nutrients to the diesel contaminated soil could reach this value in approximately 35, 26, 21 and 14 days respectively to 44 days for an un-amended soil. this biotreatment is an environmentally acceptable process which converts agricultural byproducts into water and carbon dioxide and results in the generation of metabolic energy and biomass. microorganisms concentration ratio 6 % mcr 7 % mcr 8 % mcr a v e ra g e t p h c d e g ra d a ti o n , p p m /d a y 0 100 200 300 400 th po th+po fig. 4 average hydrocarbon degradation response to both fungi stains and ratios with 8 % nwr and c/n/p= 35/10/1, c/k=10 microorganisms concentration ratio 6 % mcr 7 % mcr 8 % mcr a v e ra g e t p h c d e g ra d a ti o n , p p m /d a y 0 100 200 300 400 500 th po th+po fig. 5 average hydrocarbon degradation response to both fungi stains and ratios with 8 % nwr and c/n/p= 100/60/10, c/k=10 time, days 0 7 14 21 28 35 42 49 t p h c d e g ra d a ti o n , p p m 0 5000 10000 15000 20000 25000 fig. 6 hydrocarbon degradation over time during the biotreatment of diesel contaminated soil at 8 % mcr, 8 % nwr and c/n/p=100/60/10, c/k=10 time, days 0 7 14 21 28 35 42 49 t p h c d e g ra d a ti o n , p p m 0 5000 10000 15000 20000 25000 no nutrients 6 % nwr, c/n/p=35/10/1, c/k=10 6 % nwr, c/n/p=100/60/10, c/k=10 8 % nwr, c/n/p=35/10/1, c/k=10 8 % nwr, c/n/p=100/60/10, c/k=10 fig. 7 hydrocarbon concentrations in soils over time with 7 % mcr of both fungi together muna h. al-joubori and ayad a. a. h. abd al-razaq 73 ijcpe vol.9 no. 2 (june 2008) conclusions the following conclusions were observed from this study: 1. the biotreatment results of trichoderma harizanum are relatively close to those of pleurotus ostreatus. it can be noticed that at the same value of mcr and with each strain of fungi, the reduction in tphc is mostly identical. 2. using both strains together gave better hydrocarbon degradation than alone usage. 3. degradation in tphc increases with an increase in mcr. 4. degradation in tphc increases with nutrients addition. 5. the nutrient ratios are added to make a progress in biotreatment of petroleum compounds that are difficult to degrade by the site’s indigenous biota. in other words, adding nutrient amendments to diesel contaminated soil can enhance biotreatment rates rather than the case of un-amended soil. 6. the enhancing in hydrocarbon degradation with both fungi strains together is reasonableexpected matter due to the double action in producing extra-enzyme that showed the ability to treat the present contamination. 7. this study proved that the selected fungi can be considered as hydrocarbon degradation microorganisms. also the new ratio of nutrients components which expressed as c/n/p=100/60/10 with c/k=10 can be recommended to give best microbial growth and diesel degradation. 8. the suitability of using different cheep and available agricultural waste substrate in the cultivation of the microorganisms understudy made this kind of treatment to be considered an effective treatment option for petroleum hydrocarbon contaminated soils. 9. if the limiting factors such as temperature, moisture, nutrients and c/n ratio of the compost are not adequately addressed, the resulting is a long treatment period. 10. the best reduction in tphc (within this study) can be observed at the case of using the both fungi together, amended soil with c/n/p= 100/60/10, c/k=10, 8 % nwr and 8 % mcr, which gave an average of 395 ppm per day. in comparison with biodegradation rates reported in the literatures for other sites, this is good rate for biodegradation. reference 1. international association of oil and gas producers “environmental aspects of the use and disposal of non-aqueous drilling fluids associated with offshore oil and gas operations”, report 342, (2003). 2. mcmillen, s.j. and gary, n. r., “biotreatment of exploration and production wastes”, spe 27135, presented at the second international conference on health, safety and environment in oil and gas exploration and production, jakarta, indonesia, january 25-27 (1994). 3. zobell, c. e.: “assimilation of hydrocarbons by microorganisms”, adv. enzymol, no. 10, pp. 443-486, (1950). 4. beerstecher, e.: “petroleum microbiology,” elsevier publishing company, amsterdam, pp. 375, (1954). 5. davis, j. b.: “petroleum microbiology,” elsevier publishing company, amsterdam, london, new york, (1967). 6. chaineau, c. h., jean, c. s. and anne, m., “is biotreatment a solution for the treatment of oily waste?, ” spe 78548, presented for presentation at the 10 th abu dhabi international petroleum exhibition and conference, (2002). 7. atlas, r. m., and bartha, r.: “hydrocarbon biodegradation and oil spill bioremediation,” advances in microbial ecology, 12, pp. 287-388, (1992). 8. chaineau, c. h., morel, j. l., and oudot, j.: “biodegradation of fuel oil hydrocarbons in the rhizophere of maize, j. environ. qual., 29, pp. 569578, (2000). 9. abd al-razaq, a. a. haleem, “different techniques to minimize oil wells drilling wastes”, ph. d. thesis, university of baghdad, (2007). 10. hassan, a. a. k.: “production of fibrinolytic proteas from pleurotus ostreatus by solid state fermentation,” ph. d. thesis university of baghdad, (2005). 11. bourbonnais, r. and paice, m. g., “oxidation enzymes for the lignin degrading fungus pleurotus sajor-caju in plant cell wall polymers biogenesis and biodegradation”, american chemical society, symposium series, 399, 472-481 (1988a). biotreatment of oil wells drilling waste in an agricultural soil 74 ijcpe vol.9 no. 2 (june 2008) 12. bourbonnais, r., paice, m. g., “veratryl alcohol oxidaze from the lignin degrading basidion yeasts pleurotus sajor-caju”, biochemical journal, 255, 445-450 (1988b). 13. al-jaboury, m. h., hassen, a. a. and alani, s. r., “production of fibrinolytic protease from various fungi isolates and species”, (in press). 14. quimio, t. h., chang, s. and royer, d. j., “technical guidelines for mushroom growing in the tropics”, fao plant production and protection, paper 106, rome, italy, (1990). dr ayad _mag_.doc ijcpe vol.8 no.4 (december 2007) 59 iraqi journal of chemical and petroleum engineering vol.8 no.4 (december 2007) 59-62 issn: 1997 -4884 efficiency and reliability of reverse osmosis desalination systems ayad a. f. al-dulaimi petroleum engineering department college of engineering university of baghdad iraq abstract this study is concerned with the evaluation of the effect of euphrates river water quality in al-samawa region during the period 1984-2003 on efficiency and reliability of reverse osmosis desalination systems by calculating the calcium sulfate scaling index depending on the following indicators: tds, ca+2, mg+2, na+1, cl-1, so4-2, hco3-1. it was found from data analysis that this index for these units is greater than permissible limit. also, the fitted relationship between this index and tds is logarithmic, i.e. this index varies more rapidly than tds, and consequently it is more representative to the water quality than tds. keywords: desalination, reverse osmosis . introduction water quality control is an important protection issue. the analysis of the existing water quality parameters and trend of their change is useful for making quantitative decision, such as whether water quality is improving or getting worse over the time. these decisions are important in planning of water pollution control program. many studies concerned with quality of iraqi's river water had been done. jehad, 1984 carried out a study on the effects of tharthar canal salty water on the quality of the euphrates water. saleh, 1989 carr ied out a study on the operation rules for euphrates river system. nasser, 2001 carried out a study about the variation of salinity indication parameters of tigris river in baghdad city. al-tikriti, 2001 carried out a study on the reduction in water resources of euphrates river in iraq due to the water storage strategies adopted by turkey and syria in the last years. the study concluded that this reduction indeed affects the water quality in this river. the study predicted that further decreasing of the flo w average from 100-200 m3/sec to 50-100 m3/sec for euphrates river will result in general increase in the concentrations of the hydrochemical parameters. the maximum percentage increase in these concentrations may be 4.31% for tds and 27.9% for so 4 which indicates that the rate of increase of so4 concentration will be greater than of tds. the study indicated that the middle euphrates is the most critical area from environmental point of view. specially, this region extends from down hindiya barrage to alsa mawa city. this is because this area was suffering from low water quality because of high agricultural density. moreover, the river has many tributaries and many drains which flow into the river directly. to increase the efficiency and life of a reverse o smosis system, effective pretreatment of the feed water is required. selection of the proper pretreatment will maximize efficiency and membrane life by minimizing: fouling, scaling and membrane degradation. fouling will refer to the entrapment of particula tes such as iron floc or silt, whereas scaling will refer to the precipitation and deposition within the system of sparingly soluble salts such as calcium sulfate (caso4) (technical manual, 1995). demineralizing process, preceded by a reverse osmosis des alination units is the common practice in all electric power stations and industries demineralize water using euphrates river water (musaib and nassiriya electric power station). studies (jehad, 1984; saleh, 1989 & al-tikriti, 2001) give evidence about exceeding maximum permissible level of dissolved solid for drinking water governed by world health origination university of baghdad college of engineering iraqi journal of chemical and petroleum engineering efficiency and reliability of reverse osmosis desalination systems ijcpe vol.8 no.4 (december 2007) 60 (who) standards in most parts of euphrates river basin. this initiates the necessity of desalination of river water for drinking purpose using reverse osmosis unit on a large scale in the future, similar to the status in basrah city. in the reverse osmosis process, water flow selectively out of a concentrated salt solution, diffuses through a semi permeable membrane into a dilute solution. the limiting factor of efficiency and life of a reverse osmosis system is mostly of a chemical nature, i.e. precipitation and scale formation by calcium carbonate or sulfate. scaling of a reverse osmosis membrane may occur when sparingly soluble salts are concentrated within the element beyond their solubility limit. therefore, the risk of the scaling increases with increasing feed concentration of sparingly soluble salts (editors of power, 1967). two feed water quality indexes measure the scaling potential in reverse osmosis system. firstly, langelier saturation index (lsi) measures the tendency of calcium carbonate to precipitate from water under given conditions of calcium hardness, alkalinity, ph, temperature and total dissolved solid (technical manual, 1995 & astmd 3739-88). calcium carbonate scaling prevention can be controlled by acid addition alone so that the (lsi) in the concentrate stream must be negative (technical manual, 1995). so that calcium carbonate scaling prevention can be achieved easily. secondly, quality index is the ratio of ionic product for caso4 in the concentrate stream (ipc) to the solubility of product (ksp) in the concentrate stream. there is potential of scaling with caso4, when this index is grater than 0.8. however, this index could be 1.5 if sodium hexametaphosphate is used as scale inhibitor (tech. manual, 1995 & astm d4692-87). when the salinity of feed water to the reverse osmosis system is very high (for example, tds for brackish water ranged between 5000ppm to 15000ppm and tds for sea water in the range of 35000ppm), the lsi and caso4 scaling index is beyond adjustable limit using acid and scale inhibitor, strong acid cation exchange resin softening, weak acid cation exchange resin dealkalization or lime softening with lime or lime plus soda ash will be a must. this will increase the complexity, cost and reliability of the desalination system, so that the reliability of industrial, power generation, and drinking water system they serve (tech. manual, 1995). the aims of the pres ent study are: evaluating the calcium sulfate scaling index for a representative chemical analysis of euphrates water at selected region for a period (1984-2003), evaluating the trend of change of this index, correlating this index with tds values and evaluating the potential risk increase on efficiency and reliability of reverse osmosis units using euphrates water as feed water. study area quality of euphrates river water near al-samawa region was selected to represent the quality status of the river in this region and beyond to the south. the study area is characterized by densely agriculture activities, to the north of this area, drainage systems are being with all their pollutants disposed to euphrates river, so as waste disposal from many towns to eu phrates river directly as shown in fig.(1). the concentration of dissolved solid increased far beyond upper permissible limit that subjected by who standard as in fig.(2). so, desalination of water using reverse osmosis process is necessary and, consequently, scaling risk increased also. fig.(1):study area. 1984 1986 1988 1990 199 2 199 4 199 6 199 8 200 0 200 2 200 4 year 500 1 000 1 500 2 000 2 500 3 000 3 500 t d s for al-samawa for al-hi ndiya who max. limi t fig.(2):variation of total dissolved solid versus time (altikriti, 2001 and ministry of water resources). ayad a. f. al-dulaimi ijcpe vol.8 no.4 (december 2007) 61 procedure the annual mean of hydrochemical parameters at alsamawa region are taken fro m reference (al-tikriti 2001) for period 1984-2000 and also from the general state of dams and reservoirs/ministry of water resources for year 2003. these parameters include (tds, ca+2, mg+2, cl-1, so4 -2) concentrations are shown in table(1). records are extended from 1984 to 2003 which are considered to be both sufficient and representative to the trend of hydrochemical parameters. na +1 and hco3 -1 concentrations were calculated based on total dissolved solid (tds) and the equality of summation of equivalent weights of cations with that of anions. for the determination of the calcium sulfate scaling index (technical manual, 1995), (ipc/ksp) for each year based on data in table(1). where ipc is ion product for caso4 in concentrate stream and ksp is solubility product. a) calculate the ionic strength of the concentrate stream (ic). y ii fc − ×= 1 1 (1) where: y is recovery of the reverse osmosis system which is taken to be 0.75 as a usual value implemented in reverse osmosis system (technical m anual, 1995). if is the ionic strength of the feed water which is )( 2 1 2 iif zmi ×= ∑ (2) where: mi = molal concentration of ion (i) in (mole/kg). zi = ionic charge of ion (i). b) calculate the ion product (ipc) for caso4 in concentrate stream. ( ) ( )     − ×    − ×= −+ y so y caip f m f m c 1 1 1 1 2 4 2 (3) where: (mca+2)f =mca +2 in feed,(mole/l). (mso4 -2)f =mso 4 -2 in feed, (mole/l). c) by using calculated ionic strength of the concentrate stream (ic ) from eq.(3) and fig.(3), the solubility product (ksp) for caso4 in the concentrate stream can be specified. if ipc = ksp, caso4 scaling can occur, and adjustment is required. for a safe and conservative pretreatment design, adjustment should be made if ipc = 0.8ksp (technical manual, 1995). table(1):the annual mean of hydrochemical parameters at al-samawa region (a l-tikriti, 2001 and ministry of water resources)**. fig.(3): ksp for caso4 versus ionic strength (technical manual, 1995). results and discussion by using the procedure described in previous section, values of calcium sulfate scaling index (ipc/ksp) are calculated for euphrates river at al-samawa region for the period (1984-2003) as shown in fig.(4). these values were exceeded the upper permissible limit which is equal to (1.5) for scaling prevention of reverse osmosis system. this index reached the maximum value of (2.18) in 1992, whereas it reached minimum value of (1.13) in 2000. however, this low value is due to reduction in total dissolved solid and calcium ions concentration in the river because increasing the flow rate of the river and reducing the supply of river with water stored in altharthar depression. according to fig.(2), the total dissolved solid (tds) increases from al-hindiya region toward al-samawa city and, consequently, it is will increase beyond the al-samawa city until basrah city efficiency and reliability of reverse osmosis desalination systems ijcpe vol.8 no.4 (december 2007) 62 passing through nassiriya region and other regions. this increment will lead to increase the values of calcium sulfate scaling index (ipc/ksp) and consequently the reverse osmosis system used for desalination of water for drinking or industrial purpose will suffer from potential risk of scaling. also, the fitted relationship between calcium sulfate scaling index with tds is logarithmic as shown in fig.(5) “this fit is achieved by grapher version 1.09”. this means that this index varies more rapidly than tds and consequently it is more representative to the water quality than tds. 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 year 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 ip c /k sp r a ti o calculated d ata upp er limit fig.(4):variation of calcium sulfate index versus time for al-samawa region 1200 1600 2000 2400 2800 3200 3600 tds 1.0 1.2 1.4 1.6 1.8 2.0 2.2 ip c /k s p r a ti o fig.(5):variation of calcium sulfate index versus total dissolved solid for al-samawa region conclusions 1. calcium sulfate scaling index (ipc/kps) of euphrates water in the study area exceeds the upper limit for scaling prevention of reverse osmosis system during the study period. it reached maximum value of 2.18 in 1992. 2. the reason of reductio n of value of scaling index to lower limit in year 2000 was due to reduction in tds and calcium ions concentration in the river because increasing the flow rate of the river and reducing the supply of river with water stored in al-tharthar depression. 3. the calcium sulfate scaling index has more sense for water quality than that of tds. references 1. jehad, a.k., µµeffect of tharthar canal salty water on the quality of euphrates water¶¶, m.sc. thesis, university of tech., 1984. 2. saleh,w.m.,µµoperation rules for euphrates river system¶¶, m.sc. thesis, collage of eng., uni. of baghdad, 1989. 3. nasser, n.o., µµvariation of salinity indication parameters of tigris river in baghdad city (19901999)¶¶, m.sc. thesis, collage of eng., uni. of baghdad, 2001. 4. al-tikriti, h.n.,µµ�forecasting of pollution levels in accordance with discharge reduction in selected area on euphrates river¶¶, m.sc. thesis, callege of eng., uni. of baghadad.2001. 5. twort, a.c., law, f.m., and crowley, f.w., µµwater supply ¶¶, edwarad arnold, 1974. 6. editors of power, µµpower generation system¶¶, mcgrawhill, 1967. 7. µµfilmtec membrane elements¶¶, technical manual, dow chemical company, 1995. 8. astm d3739-88, µµstandard practice for calculation and adjustment of the langelier saturation index for reverse os mosis ¶¶ 1988. 9. astm d4692-87, µµstandard practice for calculation and adjustment of sulfate scaling salts (caso 4, srs4 and b4so4) for reverse osmosis ¶¶, 1987. 10. larsson, e., and j. persson “viability of membrane bioreactor technology as an advanced pretreatment for onsite wastewater treatment”, m.sc. thesis, lulea university of technology, etda. libraries, 2004. iraqi journal of chemical and petroleum engineering vol.17 no.3 (september 2016) 117123 issn: 1997-4884 a morphological study of alumina hollow fiber membrane asrar al-obaidy chemical engineering department, college of engineering, university of baghdad email: asrarabdullah62@yahoo.com abstract morphologies of ceramic hollow fiber membranes prepared by a combined phase-inversion and sintering method were studied. the organic binder spinning solution containing suspended al₂o₃ powders was spun to a hollow fiber precursor, which was then sintered at elevated temperatures( 300 ˚c, 1400 ˚c, 25 ˚c) in order to obtain the al₂o₃ hollow fiber membranes. the spinning solution consisted of polyether sulfone (pes), n-methyl-2-pyrrolidone (nmp), which were used as polymer binder, solvent, respectively. the prepared al₂o₃ hollow fiber membranes were characterized by a scanning electron microscope (sem). it is believed that finger-like void formation in asymmetric ceramic membranes is initiated by hydrodynamically unstable viscous fingering developed when a less viscous fluid (non-solvent) is in contact with a higher viscosity fluid (ceramic suspension containing invertible polymer binder). the effects of the air-gap (0 cm, 2 cm, 15 cm) on fibre morphology have been studied and it has been determined that viscosity due to change in air-gap is the dominating factor for ceramic systems. keywords: ceramic membrane, hollow fiber, morphology, phase inversion. introduction ceramic membranes are convincing particularly in terms of high mechanical, chemical and thermal stability compared to polymeric membranes enabling their use under harsh conditions as well as the application of chemicals and steam for membrane and module/plant cleaning. therefore, their use in a wide range of different applications from waste water treatment till clarification and sterilization of beverages are well known. due to their (in principle) unrestricted resistance against organic solvents, ceramic membranes are of particular interest for organic solvent nano filtration (osn). this growing new technology describes the application of nano filtration (nf) in pure organic solvents or organic solvent mixtures. osn has just established during the last 15 years as a result of the development of solvent stable polymeric membranes and offers a high potential for applications in pharmaceutical and chemical industries [1-3]. many different methods used for preparing inorganic hollow fibers, including dry spinning a system of inorganic material and binder [4], wet spinning a suitable inorganic materialuniversity of baghdad college of engineering iraqi journal of chemical and petroleum engineering mailto:asrarabdullah62@yahoo.com a morphological study of alumina hollow fiber membrane www.iasj.netavailable online at: 6) 201 september( 3no. 7ijcpe vol.1 111 containing solution and/or solvents [59], depositing fibers from the gas phase on to a substrate, or pyrolyzing the polymers [10-12]. in this study, we have tried to use the well-known phase-inversion method, commonly employed for spinning polymeric hollow fiber membranes, to prepare the inorganic al₂o₃ hollow fibers. factors affecting the structure and performance of the membranes such as the spinning conditions, (change in air gap here) were studied extensively, and the formation procedure of the ceramic hollow fiber membrane was also discussed. experimental 1. materials akp 30 α-al₂o₃ (al₂o₃, particle size of 0.3 μm) from (sumitomo chemicals co. ltd, japan). polyether sulfone (pes, ultrason, 6020p, basf, germany) was used as polymer and n-methyl pyrrolidone (nmp, 99.5 wt%, aldrich, the netherlands) as solvent. pes, α-al₂o₃ powder were dried before use. 2. spinning process based on the principle of phase inversion of a particle loaded polymer solution the green fibers were prepared via dry-wet spinning process. details of the spinning conditions are mentioned in table 1. table 1: spinning conditions condition value composition spinning mixture see table 2 bore liquid h₂o external coagulant h₂o mixture extrusion pressure (bar) 1 air gap (cm) 0,2,15 bore liquid flow rate (ml/min) 9 spinneret diameter (mm) od/id = 1.1/0.5 temperature (°c) 21 spinning mixture was prepared by adding the inorganic powder (see table 2) to nmp, followed by stirring for 30 min. to decrease the amount of agglomerates, ultrasonic treatment was applied for the preparation of al₂o₃ fibers for 30 min. pes was added in three steps, each separated by 2 h to prevent agglomerations, the mixture was then stirred for 16h to get a homogenous solution . the spinning mixture was degassed by applying vacuum for 30 min. finally, the degassed spinning solution was pressurized by nitrogen. a tube-inorifice spinneret (with inner diameter 0.5 mm and outer diameter 1.1 mm) was used to obtain hollow fiber precursors by wet spinning method at room temperature. table 2: composition of spinning mixture of the performed experiment material concentration particles in hf(vol%) particle size (µm) spinning mixture nmp (wt%) pes (wt%) particle (wt%) viscosity ( pa/s) al₂o₃ 58 0.3 40 10 50 42 3. drying and thermal treatment after spinning the hollow fibers were kept directly in a water bath for 24 h for completion of the phase separation process (to remove the residual solvents), followed by drying for 24h to straighten the fiber. the fibers (15 cm length) were placed into the channels (4 mm) of a multichannel ceramic, subsequently placed horizontally in a furnace with a controlled atmosphere. a detailed program of the thermal treatment can be found in table 3. a flow diagram showing the stages involved in the preparation of an inorganic hollow fiber is shown in figure 1. http://www.iasj.net/ asrar al-obaidy 111 )6201september ( 3no. 17ijcpe vol. www.iasj.netonline at: available fig. 1: flow diagram showing the stages involved in the combined phase inversion and sintering technique for ceramic hollow fiber fabrication table 3: sintering conditions temperature °c dwell min rate °c/min 300 60 5 1400 120 5 25 5 4. characterization viscosity data was collected (physica uds-200 rheometer) using cone and plate geometry at shear rates between 6 s¯¹ and 100 s¯¹ at 20 ˚c. spinning suspension samples were taken and tested immediately prior to fibre spinning. the prepared hollow fiber membranes structures were visually observed using a scanning electron microscope (jsm-6010la). the inorganic hollow fiber membranes (after calcination), the clear cross sectional fracture could be obtained by directly snapping the fiber. these membrane samples were then positioned on a metal holder and gold-coated using sputter-coating operated under vacuum conditions. the sem micrographs of both the surface and cross-section of the hollow fiber membranes were taken at various magnifications. results and discussion figure 2 a–c shows precursor fibres spun with air gaps of 0 cm, 2 cm and 15 cm, an internal coagulant flow rate of 9 ml/min and an extrusion velocity of approximately 35mm/s. it can be seen from figure 2 a that the morphology of fibres spun directly into a non-solvent bath, i.e. a 0-cm airgap consists of finger-like voids originating from both the inner and outer fibre surfaces which extend almost to the centre of the fibre crosssection. the morphology of the fibre shown in figure 2 a is believed to result from hydrodynamically unstable viscous fingering occurring simultaneously and to a similar extent at both the inner and outer fibre surfaces, this result is in agreement with [13]. a central sponge-like region is present which provides the majority of the mechanical strength and separation characteristics. maximum void length is approximately the same for voids originating from both the inner and outer surfaces and as in all the prepared fibres a void length distribution exists, some being only a few microns in length while others penetrate far into the fibre crosshttp://www.iasj.net/ http://www.sciencedirect.com/science/article/pii/s0920586110001240 a morphological study of alumina hollow fiber membrane www.iasj.netavailable online at: 6) 201 september( 3no. 7ijcpe vol.1 121 section.this structure may not be ideal for some of the principal applications of ceramic hollow fibre membranes such as solvent filtration which generally require the separation layer (packed pore mostly originated from the sponge-like region after heat treatment)to be at either the inner or outer edge. however, the above structure may be beneficial for the development of catalytic membranes, as finger-like voids may serve as substrates for catalyst particle impregnation. for example, a multifunctional catalytic membrane could be developed with different catalytic functions at the inner and outer surfaces with the central region of the membrane determining the permeation characteristics. this could be achieved by depositing two different types of catalyst targeted at different reactions within the inner and outer finger-like voids, respectively. figure 2 b shows the fibre morphology resulting from a 2 cm air gap. as shown, the finger-like voids extend from the inner surface across approximately 50% of the fibre crosssection but void length at the outer surface has been greatly reduced. a sponge-like region occupying approximately 35% of the fibre crosssection is present between the inner and outer finger-like voids. the size and number of voids at the outer edge are further reduced when the air-gap is increased to 15 cm as shown in figure 2 c. as can be seen, fingerlike voids extend from the inner surface across approximately 80% of the fibre crosssection with the remaining 20% consisting of a sponge-like region. close examination of the outer edge of the fibre, as shown in figure 2 d at increased magnification, reveals previous studies have shown that densification of sponge-like regions occurs during calcination, causing a decrease in porosity, eventually resulting in a gas tight membrane at high calcination temperatures and high al2o3/pes ratios [6, 9, 14]. a comparison of figure 2 c and f of precursor and calcined fibres spun with an air-gap of 15 cm suggests that similar results have also been observed in this work and that fingerlike voids are retained during calcination despite the densification of the sponge-like structure. the situation is somewhat different when a 2 cm air gap is present. in this case simultaneous solvent evaporation and moisture (non-solvent) condensation causes a local viscosity increase in the outer region of the fibre prior to immersion. during the time the precursor fibre is exposed to the atmosphere (2 cm air gap), the viscosity of the outer region increases and finger-like voids originating at the inner surface penetrate into the fibre cross-section. as the precursor fibre makes contact with the non-solvent bath the increased viscosity of the outer region, as a result of exposure to the atmosphere, inhibits the growth of finger-like voids at the outer edge. however, non-solvent influx from the precipitation bath does still occur, further increasing the suspension viscosity as it penetrates the nascent fibre cross-section. this increases the viscosity in front of finger-like voids growing from the inner surface, limiting their length to approximately 50% of the fibre cross-section. therefore finger-like voids forming from the inner surface can be increased in length by increasing the air-gap to 15 cm as shown in figure 2 c. under these conditions the viscosity of the outer region is higher when the nascent fibre is immersed and nonsolvent influx is reduced,while at the same time voids originating at the inner surface have more time to penetrate further towards the outer edge. http://www.iasj.net/ asrar al-obaidy 121 )6201september ( 3no. 17ijcpe vol. www.iasj.netonline at: available a b c d e f fig. 2: cross-sectional images of fibres 1-3—(a–c): precursor fibres, (d–f): sintered fibres; (a): fibre 1, 0 cm air-gap, (b): fibre 2, 2 cm air-gap, (c): fibre 3, 15 cm air-gap, (d) outer edge of fibre 3 (15 cm airgap) calcined at 1400˚c, (e) outer edge of fibre 3 (15 cm air-gap) calcined at 1600˚c and (f): fibre 3, (15 cm air-gap) calcined at 1400˚c conclusions finger-like voids in hollow fibres prepared from alumina/nmp/polyethersulfone spinning suspensions result from hydrodynamically unstable viscous fingering occurring at the interface between the suspension and the nonsolvent. above a critical suspension viscosity this phenomenon is not observed and a sponge-like membrane structure is formed. by varying the viscosity of the spinning suspension by using water as a non-solvent http://www.iasj.net/ a morphological study of alumina hollow fiber membrane www.iasj.netavailable online at: 6) 201 september( 3no. 7ijcpe vol.1 122 additive, fibre morphology can be varied greatly. exposure of the outer fibre surface to the atmosphere causes a local viscosity increase and inhibits the formation of finger-like voids in this region. however, non-solvent may diffuse through this outer layer as the fibre is immersed, halting finger-like void growth from the inner surface and creating isolated voids within the membrane cross-section if the internal coagulant flow rate is insufficient. the air-gap and suspension viscosity are critical in determining both the formation of finger-like voids and the density of the outer sponge-like region. the addition of water as a nonsolvent additive to the spinning suspension causes an increase in viscosity, a reduction in finger-like void length and favours the formation of a sponge-like structure at the outer fibre surface if an air-gap is present. acknowledgment the author gratefully acknowledge the research funding provided by shell in iraq . a trainning programm provided by mesa, university of twente, enschede, the netherlands. references 1. r.w. baker, membrane technology and applications,2nd ed, mcgraw-hill, chchester,(2004). 2. i. moch, hollow-fiber membranes, kirk-othmer encyclopedia of chemical technology ,in: kirk othmer encyclopedia of chemical technology, willey,(2005). 3. m. mulder, basic principles of membrane technology. 1 st ed, kluwer academic publishers, dordrecht,(2000). 4. r.a. terpstra, j.p.g.m. van eijk, f.k. feenstra, method for the production of ceramic hollow fibers, us patent no. 5,707,584 (1998). 5. k.h. lee, y.m. kim, asymmetric hollow inorganic membranes, key eng. mater. 61/62 ,17,(1991). 6. m.w.j. luiten-olieman, l. winnubst, a. nijmeijer, m. wessling, n.e. benes, porous stainless steel hollow fiber membranes via dry–wet spinning, journal of membrane science 370,124–130, (2011). 7. b. kingsbury, k. li, a morphological study of ceramic hollow fibre membranes, journal of membrane science 328,134–140, (2009). 8. s.-m. lee, i.-h. choi, s.-w. myung, j.-y. park, i.-c. kim, w.n. kim, k.-h. lee, preparation and characterization of nickel hollow fiber membrane, des 233, 32–39, (2008). 9. patrick de wit , emiel j. kappert , theresa lohaus, matthias wessling, arian nijmeijer, nieck e. benes, highly permeable and mechanically robust silicon carbide hollow fiber membranes, journal of membrane science 475, 480– 487,(2015). 10. j.e. koresh, a. sofer, molecular sieve carbon perm selective membrane. part i. presentation of a new device for gas mixture separation, sep. sci. technol. 18, 723, (1983). 11. j.e. koresh, a. sofer, mechanism of permeation through molecular-sieve carbon membrane, j. chem. soc., faraday trans. 82,2057,(1986). 12. v.m. linkov, r.d. sanderson, e.p. jacobs, highly asymmetrical carbon membranes, in: proceedings of the 34th iupac symposium on macromolecules, vol. 7, p. 56 ,(1992). 13. benjamin f.k. kingsbury, zhentao wu, k. li, a http://www.iasj.net/ asrar al-obaidy 121 )6201september ( 3no. 17ijcpe vol. www.iasj.netonline at: available morphological study of ceramic hollow fibre membranes: a perspective on multifunctional catalytic membrane reactors,catalysis today,156,306315,(2011). 14. s. liu, k. li, r. hughes, preparation of porous aluminium oxide (al2o3) hollow fibre membranes by a combined phaseinversion and sintering method, ceram.int. 29, (8), 875–881, (2003). http://www.iasj.net/ dr adel _mag_.doc ijcpe vol.8 no.4 (december 2007) 31 iraqi journal of chemical and petroleum engineering vol.8 no.4 (december 2007) 31-37 issn: 1997 -4884 prediction of fractional hold-up in rdc column using artificial neural network adel al-hemiri and suhayla akkar chemical engineering department college of engineering university of baghdad iraq abstract in the literature, several correlations have been proposed for hold-up prediction in rotating disk contactor. however, these correlations fail to predict hold-up over wide range of conditions. based on a databank of around 611 measurements collected from the open literature, a correlation for hold up was derived using artificial neiral network (ann) modeling. the dispersed phase hold up was found to be a function of six parameters: n, cv , dv , ρ∆ , dc µµ / , σ . statistical analysis showed that the proposed correlation has an average absolute relative error (aare) of 6.52% and standard deviation (sd) 9.21%. a comparison with selected correlations in the literature showed that the developed ann correlation noticeably improved prediction of dispersed phase hold up. the developed correlation also shows better prediction over a wide range of operation parameters in rdc columns. keywords: dispersed phase hold up, rdc, artificial neural networks (ann). introduction in the design and scale up of rdc, it is necessary to explore the hydrodynamic behavior, mass transfer mechanism, and hold up effect within the equipment under different operating conditions. dispersed phase hold up represents the total drop population in rdc column is defined as the ratio of dispersed phase to the volume of the column. the effect of the hold up on the performance of an extraction column is the most important hydrodynamic characteristic, because hold up is related to the interfacial area between the phases by: 32 6 d x a = (1) where x is the dispersed phase hold up and 32d is the sauter mean diameter. and the hold up is related to the rate of mass transfer (w) via (a) by: cavkw ∆= ... (2) wher k is the mass transfer coefficient, v is volume of the column and c∆ is the concentration driving force. in solvent extraction the re lationship between mass transfer and hydrodynamic performance is complex and there are many types of contactors each requiring a special understanding. numerous experimental studies of dispersed phase hold up, drop size, mass transfer and mixing behavior within contactors have been reported [1]. in order to determine the interfacial area of the dispersion for the mass transfer calculation using equation (2) either of the following should be known: 1. the drop residence time in the contactor. 2. the fraction of the column occupied by the dispersed phase hold up. in agitated contactors the residence time distribution is rather complex and dispersed phase hold up is therefore usually used for the estimation of interfacial area. virmijs and karmers [2] investigated performance of rdc for various values of the rotor speed, total through put and solvent to feed ratio by comparing the separating efficiency with the fractional volume of the dispersed university of baghdad college of engineering iraqi journal of chemical and petroleum engineering prediction of fractional hold up in rdc column using artificial neural networks ijcpe vol.8 no.4 (december 2007) 32 phase under the same circumstances it was found that under certain condition the efficiency decreases although the hold up of the dispersed phase increases. this effect is ascribed to back mixing in continuous phase due to entrainment by the dispersed phase. the hold up increased by increasing the solvent to feed ratio wh ile the total through put is kept constant, and the special kind of back mixing in the continuous phase impairs the efficiency of the extraction operation. logsdail et.al [3] were the first to introduce the concept of dispersed phase hold up for the characterization of column design these authors modified the concept of relating the slip velocity sv of the dispersed phase to the hold up in a two phase system by: x v x v v cds − += 1 (3) ( ) x v x v xv cdo − +=− 1 1 (4) ov is called the characteristic velocity and is defined as the mean velocity of the droplets extrapolated to essentially zero flow rates at a fixed rotor speed. many correlations have been published relating the dispersed phase hold up to the characteristic velocity in the form of equation 4 with additional factors for column size constriction and droplets coalescence and break up which could not be easily applied due to the amount of information required specially for ov . some selected reliable correlations are given in table (1). however these correlations fail to predict hold up over a wide range of conditions. thus this work was initiated in order to develop a general correlation using artificial neural network. artificial neural network (ann) from an engineering view point ann can be viewed as non linear empirical models that are especially useful in adel al-hemiri and suhayla akkar ijcpe vol.8 no.4 (december 2007) 33 representing input -output data. making predication, classifying data, reorganization patterns, and control process. ann which will be referred to as a node in this work and is analogous to a single neuron in the human brain. the advantages of using artificial neural network in contrast with first principles models or other empirical models are [4-6], 1. ann can be highly non linear. 2. the structure can be more complex and hence more representative than most other empirical models. 3. the structure does not have to be prespecified. 4. quite flexible models. (ann) have been increasingly applied to many problems in transport planning and engineering, and the feed forward network with the error back propagation learning rule, usually called simply back propagation (bp), has been the most popular neural network [7]. back-propagation back propagation was one of the first general techniques developed to train multi-layer networks, which does not have many of the inherent limitations of the earlier, single -layer neural nets. a back propagation net is a multilayer, feed forward network that is trained by back propagating the errors using the generalized delta rule [8]. the steps for backpropagation training can be shown as follows [9]: 1. initialize the weights with small, random values. 2. each input unit broadcasts its value to all of the hidden units. 3. each hidden unit sums its input signals and applies its activation function to compute its output signal. 4. each hidden unit sends its signal to the output units. 5. each output unit sums its input signals and applies its activation function to compute its output signal. 6. each-output unit updates its weights and bias: the conventional algorithm used for training a mlff is the bp algorithm, which is an iterative gradient algorithm designed to minimize the mean-squared error between the desired output and the actual output for a particular input to the network [10]. basically, bp learning consists of two passes through the different layers of the network: a forward pass and backward pass. during the forward pass the synaptic weights of the network are all fixed. during the backward pass, on the other hand, the synaptic weights are all adjusted in accordance with an error-correction rule [11]. the algorithm of the error back-propagation training is as given below [10]: step 1: initialize network weight values. step 2: sum weighted input and apply activation function to compute output of hidden layer       = ∑ i ijij wxfh (4) where, hj: the actual output of hidden neuron j for input signals x. xi: input signal of input neuron (i). wij: synaptic weights between input neuron hidden neuron j and i. f : the activation function. step3: sum weighted output of hidden layer and apply activation function to compute output of output layer.       = ∑ j jkjk whfo (5) where ok: the actual output of output neuron k. wjk: synaptic weight between hidden neuron j and output neuron k. step 4: compute back propagation error ( )        −= ∑ j jkjkkk whfod 'δ (6) where f’: the derivative of the activation function. dk: the desired of output neuron k. step 5: calculate weight correlation term ( ) ( )1−∆+=∆ nwhnw jkjkjk αηδ (7) step 6: sums delta input for each hidden unit and calculate error term. ( )∑= ijijkkj wxfw 'δδ (8) step 7: calculate weight correction term ( ) ( )1−∆+=∆ nwxnw ijijij αηδ (9) step 8: update weights ( ) ( ) ( )nwnwnw jkjkjk ∆+=+ 1 (10) step 9: repeat step 2 for a given number of error ( )       −= ∑∑ p k p k p k odp mse 2 2 1 where p is the number of patterns in the training set. step 10: end bp is easy to implement, and has been shown to produce relatively good results in many applications. it is capable of approximating arbitrary non-linear mappings. prediction of fractional hold up in rdc column using artificial neural networks ijcpe vol.8 no.4 (december 2007) 34 however, it is noted that two serious disadvantages in the bp algorithm are the slow rate of convergence, requiring very long training times, and getting stuck in local minima. the success of bp methods very much depends on problem specific parameter settings and on the topology of the network [ 9]. the activation function used with the backpropagation there are three transfer functions most commonly used for back propagation, but other differentiable transfer functions can be created and used with back propagation if desired. these functions are tansig, logsig, and purelin. the function logsig generates outputs between 0 and 1 as the neuron's net input goes from negative to positive infinity. alternatively, multilayer networks may use the tan sigmoid transfer function. occasionally, the linear transfer function purelin is used in back propagation networks. [8]. if the last layer of a multilayer network has sigmoid neurons, then the outputs of the network are limited to a small range. if linear output neurons are used the network outputs can take any value. in the present simulation the tansig is used. modeling correlation of ann the modeling of ann correlation began with the collection of large data bank followed by the learning file which was made by randomly selecting about 70% of the data base to train the network. the remaining 30% of data is then used to check the generalization capability of the model. the last step is to perform a neural correlation and to validate it statistically. so that the steps of modeling are: collection of data the first step is collection of data.. many investigators studied the hydrodynamics of rdc based on the dispersed phase hold up. in this model about 611 experimental points have been collected for mass transfer from continuous to dispersed phase (c —>d), for mass transfer from dispersed to continuous (d —>c) and for the case of no mass transfer in rdc. the data were divided into training and test sets: the neural network was trained on 70% of the data and tested on 30%. the data includes nine chemical systems with a large range of rotary speed, velocity of both continuous and dispersed phase as well as the physical properties for each chemical system. all of these parameters are input to neural network and there is one output; it is the hold up of dispersed phase. the structure of artificial neural network in this work, a multilayer neural network has been used, as it is effective in finding complex non-linear relationships. it has been reported that mu ltilayer ann models with only one hidden layer are universal approximates. hence, a three layer feed forward neural network is chosen as a correlation model. the weighting coefficients of the neural network are calculated using matlab programming. structure of artificial neural network built as: 1. input layer: a layer of neurons that receive information from external sources and pass this information to the network for processing. these may be either sensory inputs or signals from other systems outside the one being modeled. in this work six input neurons in the layer and there is a set of (427) data points available for the training set. 2. hidden layer: a layer of neurons that receives information from the input layer and processes them in a hidden way. it has no direct connections to the outside world (inputs or output). all connections from the hidden layer are to other layers within the system. the number of neuron in the hidden layer is twenty one neurons. this gave best results and was found by trial and error. if the number of neurons in the hidden layer is more, the network becomes complicated. results probably indicate that, the present problem is not too complex to have a complicated network routing. hence, the results can be satisfactorily achieved by keeping the number of neurons in hidden layer at a best value of twenty one neurons. 3. output layer: a layer of one neuron that receives processed information and sends output signals out of the system. here the output is the hold up of dispersed phase in rdc. 4. bias: the function of the bias is to provide a threshold for activation of neurons. the bias input is connected to each of hidden neurons in network. the structure of muiti layer ann modeling is illustrated in figure (1). adel al-hemiri and suhayla akkar ijcpe vol.8 no.4 (december 2007) 35 training of artificial neural network the training phase starts with randomly chosen initial weight values. then a back-propagation algorithm is applied after each iteration, the weights are modified so that the cumulative error decreases. in back-propagation, the weight changes are proportional to the negative gradient of error. more details about this learning algorithm is shown in figure (1). back-propagation may have an excellent performance. this algorithm is used to calculate the values of the weights and the following procedure is then used (called "supervised learning") to determine the values of weights of the network: 1. for a given ann architecture, the value of the weights in the network is initialized as small random numbers. 2. the input of the training set is sent to the network and resulting outputs are calculated. 3. the measure of the error between the outputs of the network and the known correct (target) values is calculated. 4. the gradients of the objective function with respect to each of the individual weights are calculated. 5. the weights are changed according to the optimization search direction. 6. the procedure returns to step 2. 7. the iteration terminates when the value of the objective function calculated using the data in the test approaches experimental value. the trial and error to find the best ann correlation model is shown in table 2. table (2) network parameters in ann model network parameters structure mse no. of iteration learning rate momentum coefficient transfer function [6-16-1] 0.1 2590 0.7 0.9 tan sigmoid [6-18-1] 0.01 4321 0.65 0.9 tan sigmoid [6-21-1] 0.0001 9103 0.75 0.9 tan sigmoid with reduced mse (mean square error) the network is more accurate, because mse is defined as: ( )       −= ∑∑ p k p k p k odp mse 2 2 1 (13) where p is the number of patterns in training set, k is the number of iterations, pkd is the desired output, p ko is the actual output. the learning process includes the procedure when the data from the input neurons is propagated through the network via the interconnections. each neuron in a layer is connected to every neuron in adjacent layers. a scalar weight is associated with each interconnection. neurons in the hidden layers receive weighted inputs from each of the neurons in the previous layer and they sum the weighted inputs to the neuron and then pass the resulting summation through a non-linear activation function (tan sigmoid function). artificial neural networks learn patterns can be equated to determining the proper values of the connection strengths (i.e. the weight matrices wh and wo illustrated in figure 1) that allow all the nodes to achieve the correct state of activation for a given pattern of inputs. the matrix, bias, and vector, given equations (14), (15), and (16) illustrate the result of coefficient weights for ann correlation , where wl is the matrix containing the weight vectors for the nodes in the hidden layer, wo is the vector containing the weight for the nodes in the output layer and is the bias. (14) (15) (16) prediction of fractional hold up in rdc column using artificial neural networks ijcpe vol.8 no.4 (december 2007) 36 simulation results the network architecture used for predicting hold up is illustrated in figure (1) consist of six inputs neurons corresponding to the state variables of the system, with 21 hidden neurons and one output neuron. all neurons in each layer were fully connected to the neurons in an adjacent layer. the prediction of ann correlation result is plotted in figure (2) compares the predicted hold up with experimental hold up for training set figure (2) comparison between experimental and predicted hold up in training set figure (3) comparison between experimental and predicted hold up in testing set test of the proposed ann the purely empirical model was tes ted on data that were not used to train the neural network and yielded very accurate predictions. having completed the successful training, another data set was employed to test the network prediction hold up. we made use of the same model to generate (184) new data values. the result of prediction is plotted with experimental values as shown in figure (3). statistical analysis statistical analysis based on the test data is calculated to validate the accuracy of the output for pervious correlation model based on ann. the structure for each model should give the best output prediction, which is checked by using statistical analysis. the statistical analysis of prediction is based on the following criteria: 1. the aare (average absolute relative error) should be minimum: ∑ − = n erimental erimentalprediction x xx n aare 1 exp exp1 (17) where n here is the number of data points. x is the hold up. 2. the standard deviation should be minimum. ( )[ ] ∑ − −− = 1 / 2 expexp n aarexxx sd erimentalerimentalprediction (18) 3. the correlation coefficient r between input and output should be around u nity. ( )( ) ( ) ( )∑∑ ∑ == = −− −− = n i predictionprediction n i erimentalerimental n i predictionipredictionerimentalierimental xxxx xxxx r 1 2 1 2 expexp 1 )(exp)(exp (19) where erimentalx exp =hold up mean of experimental points, predictionx =hold up mean for prediction points. the literature correlations (in table 1) were used to estimate the hold up. these correlatio ns show a poor agreement between the prediction and experimental hold up value compared with ann correlation. table (3) gives information of comparing these correlation with ann prediction in testing set. table (3) comparison of ann and previous literature correlations in testing set correlation aare% s.d% r kastkin(1962) 51.93 32.55 0.695 murakami(1978) 41.29 23.94 0.7914 hartland(1987) 32.79 22.59 0.778 kalaichelvi(1998) 32 27.63 0.726 ann (this work) 6.52 9.21 0.998 adel al-hemiri and suhayla akkar ijcpe vol.8 no.4 (december 2007) 37 conclusions the ann correlation shows noticeable improvement in the prediction of dispersed phase hold up. the neural network correlation yield an aare of 6.52% and standard deviation of 9.21%, which is better than those, obtained for the selected literature correlations. also ann correlation yielded improved predictions for variety of liquid systems and a wide range of operating parameters. the number of input units and output units are fixed to a problem (here, 6 and 1 respectively) but the choice of the number of the hidden units is flexible. in this work best results were obtained employing 21 hidden neurons. nomenclature a interfacial mass transfer area m2/m3 b bias c∆ concentration driving force kg/m 3 32d sauter mean diameter dr diameter of rotary disk m ds stator ring opening m dt diameter of rdc column m f the activation function f' the derivation of the activation function g gravitational constant m/s2 hi the actual output of hidden neuron j k mass transfer coefficient ̀ m/s n number of input neurons n speed of rotor dist rps ok the actual output of neuron k p the number of patterns in the training set r correlation coefficient v volume of column m3 vc velocity of continuous phase m/s vd velocity of dispersed phase m/s vo characteristic velocity m/s vs slip velocity m/s w rate of mass transfer kg/s wij synaptic weights between input and hidden neuron wj k synaptic weights between input and output neuron x hold up xi input vector x mean hold up zc height of compartment m zt height of rdc column m greek symbols α momentum to accelerate the network convergence process kδ the error term η the learning rate µ viscosity kg/m.s σ interfacial tension n/m ρ density kg/m3 ρ∆ density difference kg/m 3 subscripts c continuous phase d dispersed phase references 1. bailes, p.j., gledhill, j., godfrey, j.c and slater, m.j, "hydrodynamic behavior of packed, rotating disc contactor, and kuhn", chem. eng. res. des, 64, 43-55, (1986). 2. vermijs, h.j., and kramers, h., "liquid -liquid extraction in rotating disc contactor", chem. eng. sci., 3, 55-64, (1954). 3. • logsdail, d.h., thomton, j.d., and pratt, h.r.c., "liquid-liquid extraction part xii: flooding rates and performance data for a rotating disc contactor", trans. inst. chem. eng., 35, 301-315, (1957). 4. david m.h., "applications of artificial neural networks in chemical engineering", korean. j. chem. eng., 17, 373-392, (2002). 5. patterson, "artificial neural networks theory and applications". prentice hall, (1996). 6. sivanadam, s.n., "introduction to artificial neural networks", vikas publishing house pvt. ldt, (2003). 7. freeman, j.a., and skapura, d.m., "neural networks", jordan university of science and technology, july (1992). 8. matlab, version 7, june 2003, "neural network toolbox" 9. leonard, j., and kramer, m.a., "improvement of the back-propagation algorithm for training neural networks", comp. chem. eng, 14, 337-341, (1990). 10. lendaris, g., "supervised learning in ann from introduction to artificial intelligence". new york, april 7, (2004). 11. lippmann, r.p., "an introduction to computing with neural nets", ieee magazine, april, pp.4-22,(1987). 12. kalaichelvi, p., murugesan, t., "dispersed phase hold up in rotating disc co ntactor", bioprocess engineering, 18,105-111, (1998). 13. kasatkin, a.g., and kagan, s.z appl., chem., ussr, 35, 1903, (1962) [cited in murakami, a., and misonou, a., and inoue, a., 1978]. 14. kumar, a., and hartland, s., "independent prediction of slip velocity and hold up in liquid -liquid extraction columns", can. j. chem. eng., 67, 17, (1987). 15. murakam, a., misonou, a., inoue, k., " dispersed phase hold up in a rotating disc extraction column", international chemical engineering, 18,1, (1978). available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.20 no.1 (march 2019) 53 – 64 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: mahmoud jasim al-khafaji, email: m.jassimabd@gmail.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. using elastic properties as a predictive tool to identify porefluid type in carbonate formations mahmoud jasim al-khafaji and wafaa’ mustafa al-kattan petroleum engineering department-college of engineeringuniversity of baghdad abstract the aim of this study is for testing the applicability of ramamoorthy and murphy method for identification of predominant pore fluid type, in middle eastern carbonate reservoir, by analyzing the dynamic elastic properties derived from the sonic log. and involving the results of souder, for testing the same method in chalk reservoir in the north sea region. mishrif formation in garraf oilfield in southern iraq was handled in this study, utilizing a slightly-deviated well data, these data include open-hole full-set logs, where, the sonic log composed of shear and compression modes, and geologic description to check the results. the geolog software is used to make the conventional interpretation of porosity, lithology, and saturation. also, include pvt and water analyses as inputs in batzle and wang correlations in order to calculate mechanical properties of oil and water at reservoir conditions. the shear velocity and density logs are used to calculate the shear modulus (g), for each (0.1254) meter. the dry frame bulk modulus correlation of the original method was not followed, instead, a new dry frame bulk modulus correlation of saxena is used to avoid the uncertainty in the porosity type exist in the formation which needs special core description. then, gassmann’s equations were used to determine the bulk moduli of the rock assuming two saturation conditions; the first is 100% water saturated, and the second is 100% oil saturated. using elastic properties equations of love’s, and the resulted bulk moduli, two corresponding ∆t(s), (for oil and for water), were computed for each depth level. then these ∆t(s) were plotted with sonic ∆t in the same track, and compiled with the conventional log interpretation, to compare the results. the method was a good indicator of the fluid type in the high porosity zones, unlike for the tight or clay-rich zones. the results are very conformable to the conventional interpretation, the owc in both model and conventional interpretation are so close with error percentage of (0.03%). keywords: elastic properties, mishrif formation, sonic log. received on 10/10/8102, accepted on 18/12/8102, published on 30/03/8109 https://doi.org/10.31699/ijcpe.2019.1.8 1introduction fluid identification from well logs depends on the radioactive logs (neutron and density) and resistivity, which do not always give the true fluid type in the formation especially in the shaly and low resistivity. hence, the need for a new method independent from resistivity and neutron/density method and more accurate is required. the sonic log applications in petrophysics, witnessed an obvious advancement, recently. where, researches presented many of its great advantages, as an interpretive tool in petrophysics. this study described the application of a method published by ramamoorthy and murphy ‎[1], to identify the dominated pore fluid type in a high porosity middleeastern carbonate using modern logs and the work of souder ‎[2], who used a similar principle to predict pore fluid type in chalk reservoir in the north sea. 1.1. the physics of sonic log the monopole transmitter in the sonic tool emits sonic waves, which, also known as “elastic waves”, who are mechanical disturbances that propagate through the formation rocks. such waves are able to travel over very long distances through the formation, and thus bring us information about portions of the formation that are otherwise inaccessible ‎[3]. these waves in rocks propagate with a velocity that is given by elastic properties and the density of the rock ‎[4]. these parameters depend on other parameters such as porosity, pressure, mineral composition, depth, and fluid type and saturation ‎[5]. thus elastic waves also provide a method by which specific formation parameters can be estimated in the field. these elastic waves that propagate in a fluid-filled borehole into the formation during sonic logging operation are known as body waves, where two important types of energy transport mechanisms are supported by the elastic media (formation): compressional waves and shear waves. https://doi.org/10.31699/ijcpe.2019.1.8 m. j. al-khafaji and w. m. al-kattan / iraqi journal of chemical and petroleum engineering 20,1 (2019) 53 – 64 45 where, the compressional waves, also known as longitudinal waves, in this wave the particles move in a direction parallel to the direction of propagation. the speed of propagation is largest for this kind of wave compared to others and so it arrives first. it is the only wave propagated in liquids ‎[6]. while the shear waves, also known as transverse waves, particle movement is in a direction perpendicular to the wave direction. as mentioned, the speed of propagation is less than the p-wave with a ratio of about (1.6–2). no shear waves are transmitted in fluids because the presence of shear waves requires the medium to possess shear strength. in the formation, sound energy is transmitted by both compressional and shears waves. in the mud, energy is transmitted solely by compressional waves. the energy transmitted by the slower shear wave is much higher than that of the compressional wave which is first to arrive. in the wave pattern received, we can identify the shear wave by this feature ‎[6], see fig. 1. fig. 1. time vs amplitude plot illustrating sonic wave's arrival sequence, ref [4] 1.2. study objectives in this study, the applicability of a method using sonic waves as a qualitative tool, to identify the presence of hydrocarbon as a prevailed pore fluid in mishrif formation in southern iraq, was tested, by applying the result of work of ramamoorthy and murphy ‎[1], to identify the dominated pore fluid type in a high porosity middle-eastern carbonate using modern logs and the work of souder [2], who used a similar principle to predict pore fluid type in chalk reservoir in the north sea. 2area of case study and geologic setting mishrif formation which is a carbonate formation of cretaceous age was deposited in mesopotamian basin during the late cenomanian to early turonian (95 ma) ‎[7]. mishrif formation is handled in this study in garraf oilfield within the euphrates subzone in the mesopotamian zone of the stable shelf ‎[8], fig. 2, garraf oilfield is situated in southern iraq, in thi qar governorate about 85km to the north of nassriya city, fig. 2. this oilfield was discovered in 1984. it has low relief gentle anticlinal structure aligned in nw-se direction and has a dimension of (10km in width x 31 km in length) ‎[9]. it has proven by exploration and appraisals wells in garraf, to have hydrocarbon accumulation in primary oil accumulation zones, which are the mishrif and yamama formations, mishrif contains 70% of the field’s reserve ‎[9], and secondary accumulation zones, are in ratawi and zubair formations, as shown in (appendix a). 3shear and bulk moduli 3.1. bulk modulus (k) also known as “incompressibility”, it is a measure of the stress/strain ratio when a body is subjected to uniform compressive stress. where, it is equal to the change in applied pressure (∂p) divided by the ratio of the change in volume to the original volume of a body (∂v/v) by ‎[5]: ⁄ (1) the bulk modulus is the reciprocal of the compressibility. it reflects how resistive (incompressible) is the material to an overall gain or loss of volume in conditions of hydrostatic stress. 3.2. shear modulus (g) also known as “modulus of rigidity”, it describes the ratio of shear stress (f/a) to shear strain (θ). g is defined as ‎[5]: ⁄ (2) the shear modulus is associated with a change in shape of the body where it is a measure of the ability of a solid material to resist the deformations in its shape by shear forces. it is one of the lamé constants. in the other hand, fluids do not have any shear resistance, consequently zero shear modulus. so it would equal in both dry and saturation conditions for the same rock ‎[2], ‎[3]. m. j. al-khafaji and w. m. al-kattan / iraqi journal of chemical and petroleum engineering 20,1 (2019) 53 – 64 44 fig. 2. geographical location of area of study 4sonic waves in fluid-saturated porous media the rock-fluid system is so complicated that virtually all the theories for such a system have to make major assumptions to simplify the mathematics ‎[10]. in order to describe the rock theoretically, it’s a heterogeneous system with internal structure, which must be idealized in order to derive the formulations of elastic rock properties in terms of volume fractions and properties of the components (minerals and fluids), the rock texture, pressure, etc. in all cases, models are an idealization ‎[11], ‎[12]. one of the common “models”, that handle the theories of elastic properties and sonic wave's propagation in porous media, is “gassmann model (1951)” ‎[13]. he developed a model for porous rocks that allows the prediction of changes in seismic velocities because of different fluid saturations in reservoirs. where this model enables analysts to use elastic velocities in rocks saturated with one fluid to predict those of rocks saturated with a second fluid, or equivalently, predicting saturated-rock velocities from dry-rock velocities, and vice versa ‎[11]. this is the fluid substitution problem ‎[14]. this model relates the saturated bulk modulus of the rock to its porosity, the bulk modulus of the porous rock frame, the bulk modulus of the mineral matrix, and the bulk modulus of the pore-filling fluids, as in eq. (3). also, this model made the first attempt to formulate a theoretical expression for acoustic velocities in fluid-saturated porous media ‎[15]. gassmann’s assumptions were; the porous material is isotropic, elastic, monomineralic (composed of single mineral, e.g. calcite), and homogeneous, and pore space is well connected and in pressure equilibrium (zero frequency limit), the medium is a closed system with no pore fluid movement across boundaries also there is no chemical interaction between fluids and rock frame (shear modulus remains constant) ‎[16], ‎[13]. gassmann model (1951), notation can be summarized, as shown in fig. 3: ( ( ⁄ )) ( ⁄ ) ( ) ( ⁄ ) (3) where the subscripts “b”, “ma”, “fl”, and “fr” refer to the bulk, matrix, fluid, and dry rock frame (skeleton), respectively. note that dry-rock properties gfr and kfr are functions of φ. fig. 3. gassmann model notation the major simplification incorporated is that the relative motion between the fluid and skeleton during acoustic wave propagation is negligible. the model used the bulk modulus because as mentioned above, it’s more sensitive to fluid saturation, unlike the shear modulus. therefore, any fluid saturation effect should correlate mainly to a change in the bulk modulus ‎[16]. 5the theory ramamoorthy and murphy theory ‎[1], on which this study has been based on, relies mainly on the shear and bulk moduli of formation, which can be computed from the relations derived by love, eq (4) & (5), where love has related shear and compression wave velocities, vp and vs to the elastic properties of solids through ‎[17]: (4) (5) the principle of this method is that at any given depth, the porosity (φ), matrix bulk modulus (kma), and frame bulk modulus (kfr), will be constant and only the bulk modulus (kb) will change due to change in fluid content. thus a synthetic compressional transit time for each fluid will be calculated from the bulk modulus (kb), and the pore fluid is qualitatively identified by the position of the actual compressional transit time log relative to the computed curves ‎[1], ‎[2], ‎[3], ‎[5], ‎[13]. 6application to apply this method, follow simple steps, which are summarized below, can be followed to compute all the necessary parameters. 1perform the pre-interpretation calculations which are:  from rhob and nphi logs, compute total porosity. as follows: (6) m. j. al-khafaji and w. m. al-kattan / iraqi journal of chemical and petroleum engineering 20,1 (2019) 53 – 64 45  from temperature, salinity, api, and fresh water density calculate the fluid bulk moduli and velocities of fluids (oil and water), using batzle and wang formulas ‎[18], ‎[19].  for oil ( ⁄ ) ( ) (7) we consider the effect of reservoir pressure first by: (8) where: ρp: oil density corrected for the reservoir pressure effect to account for the effect of temperature, which is larger than pressure effect: (9) where: ρ@p&t : oil density corrected for pressure and temperature effects, then oil density should be corrected for dissolved gas effect by involving the gas oil ratio (rg), which in turns depends on formation volume factor (bo) ‎[19]: ́ (10) * + (11) bo from standings 1962 [19]: * + (12) using the corrected oil density for pressure, temperature, and gas effect (ρ’oil), the sonic velocity in oil will be: ( ) (13) for water first, we find the fresh water density (ρw) at reservoir pressure and temperature by: (14) then using fresh water density, formation water salinity, pressure, and temperature, the brine (formation water) density, can be calculated as: (15) then the sonic velocity in brine (vbrine) can be found from eq (16), as: (16) where: vw: sonic velocity in fresh water at reservoir pressure and temperature: ∑ ∑ (17) where: i/j as shown in table 1. table 1. i/j values for eq (17) i/j 0 1 2 3 0 1402.85 1.524 3.44e-03 -0.00001197 1 4.871 -0.0111 1.74e-04 -1.63e-06 2 -0.04783 2.75e-04 -0.000002135 1.24e-08 3 1.49e-04 -6.50e-04 -1.46e-08 1.33e-10 4 -2.20e-07 7.99e-10 5.23e-11 -4.61e-13 where: voil and vbrine, and vw in m/s, api in degrees, t in celsius degrees, p in mpa, and s is the weight fraction (ppm/l000000) of sodium chloride. the computed properties and results of these equations are listed in appendix b, (tables 2&3), 1predict fluid bulk modulus love’s expression is used, eq (5), with (vs =0) is the fluids do not sustain shear waves 2ramamoorthy and murphy ‎[1], and souder ‎[2], have used lab derived quadratic correlations to derive the dry frame modulus, as in eq (18), which are based on porosity type, and thus, detailed core analyses are needed to confirm the porosity type (either intergranular or spherical), in order to use the appropriate formula for frame bulk modulus (kfr). where ramamoorthy and murphy construct these correlations from laboratory mechanical properties measurements on core samples ‎[1], two separate trends were observed between the porosity and the ratio of the dry porous rock frame bulk modulus (kfr)to the shear modulus (g). they used scattering theory to show these trends correspond to two types of pore systems, intergranular porosity and spherical (or vugular) porosity. the graph was hand digitized and regressioned in specialized statistical software to produce the best fit line, as shown in fig. 4, they were represented by a quadratic equation of the formula ‎[2], ‎[5]: (18) they compute the shear modulus (g) using love expression, eq (4), where the inputs are expressed using the appropriate unit conversion constant, the shear wave slowness ∆ts in units of psi/ft., the bulk density ρb in gm/cc, and the shear modulus in units of gigapascals (gpa) as: (19) to avoid the necessity for core analyses, which are not always available, and if available sometimes not so much detailed to tell the porosity type, therefore, in this study a better representative correlation was implemented, to compute dry frame bulk modulus, which is dependent on lithology, not on porosity type. m. j. al-khafaji and w. m. al-kattan / iraqi journal of chemical and petroleum engineering 20,1 (2019) 53 – 64 46 hence, no need to know the porosity type, which is very heterogenous in nature, where it may be different in new wells from that well where the core was taken from. and from the application it gives a very precise prediction, instead of the relations suggested by the previous authors, where their correlations led to misleading results in many occasions, in addition to that, they are of limited benefit in zones, where the porosity is less than 10 p.u. saxena ‎[20], found that from laboratory data, it is possible to estimate a theoretical dry frame bulk modulus, only from lithological considerations knowing their porosity and vp to vs ratio. the proposed relation is combined with the advantage of pickett’s unique result of constant vp/vs ratio of (1.9) in limestone independent of pressure and porosity ‎[21]. it leads to evaluate a dry frame bulk modulus from porosity in an exponential equation, of the form: ( ) (20) where (21) kfr: dry frame bulk modulus, gpa. vp/vs: compressional to shear velocity ratio, unitless φ: porosity, fraction. fig. 4. laboratory measurements of the ratio of the bulk modulus kfr of a dry porous limestone ("framework") to the shear modulus of the same specimen plotted against porosity for a number of samples. acoustic scattering theory was used to determine that two types of pores exist in this sample set, and the lines fit these respective pore models ‎[1] since the fluids commonly encountered in the borehole environment cannot support shear stresses (gfl=0), as mentioned earlier, consequently, the shear modulus (gb) of a fluid-saturated porous rock will be identical to the dry porous rock shear modulus (gfr), because it related to the solid part of the rock only, and (g) will be used in equations for both dry and fluid-saturated rocks. 3the bulk modulus of the formation kb, then can be computed from kfr, porosity, pore fluid bulk modulus kfl and the matrix bulk modulus kma using an equation of gassmann, (eq 3). thus, at any particular depth, φ, kma, and kfr are constant and the bulk modulus will change as the fluid content is altered, so a new fluid bulk modulus will be assigned to each type of fluids, (oil and water), respectively. it can be used to predict fluid type in the reservoir, and to monitor fluid in the reservoir with time. 4from love formula [17], using the two different fluid moduli corresponding to oil, and water. from each of these bulk moduli, compressional travel time can be calculated: √ (22) 5after the two fluid compressional wave travel times corresponding to the two different fluids have been calculated for each depth, a well log plot is generated of them and the actual logged compression wave slowness is superimposed on the same plot. 6the calculated curve that best matches the measured δtc log identifies the fluid, because of the bulk modulus will be identical to the actual modulus. 7results and discussion ramamoorthy and murphy [1], showed that they have concluded a method to predict the relative amounts of spherical and intergranular porosity at each depth level, but did not divulge how this is accomplished. since no method for making this distinction was available, souder [2], used in his study, generated two separate sets of curves for a test well, for each of the relationships in fig. 4 (that is, using two different sets of coefficients in eq (14), but, as long as the core analysis is still immature in the study area, so the results could be highly erroneous, when the porosity type is unknown for sure. hence a new correlation for dry frame bulk modulus was involved instead of the previous procedure followed by previous authors, hence saxena’s equation [19], was used, which requires only the type of lithology and if it is unknown, the velocity ratio can be used directly, even the results are much more realistic than the previous method. appendix (c) represents a well log plot of these result sets of model curves for the studied well in garraf oilfield, which is targeting mishrif reservoir and using open hole log data as input including zone by zone comparison and discussion along the well. the well was drilled to the mishrif reservoir as predominantly oil producing well which under-saturated oil is bearing formation. m. j. al-khafaji and w. m. al-kattan / iraqi journal of chemical and petroleum engineering 20,1 (2019) 53 – 64 47 matrix bulk modulus used (in gpa units) is (kma = 70.3) gpa, for limestone. while the parameters of fluids (oil and water), used in the correlations are listed in (appendix b: table 2 & 3), respectively. as shown in fig. 5, that the brine bulk modulus values of mishrif water-bearing zones are varying with small increments almost equal, due to density and velocity values are almost equal, as the temperature, and salinity of the different mishrif members are similar, despite the slightly increasing pressure with depth. fig. 5. brine bulk modulus vs density of water-bearing zones of mishrif fn in fig. 6, oil bulk modulus vs api gravity, where it is obvious that the bulk modulus id decreasing with increasing api gravity, which is in turns increasing with depth in our case study, due to the effect of dissolved gases is higher, where we can see the difference between the dead oil and live oil bulk modulus values in appendix b, (table2), where the effect of gases in live oil, reduced the values of bulk modulus vitally. fig. 6. live oil bulk modulus vs api gravity of oilbearing zones of mishrif formation (appendix c), represent the conventional interpretation of open hole data and the proposed method modeled curves, the depths provided are in measured depth and tvdss, the first track includes gamma-ray and bit size and caliper logs, the second represents the effective and total porosities (phie, phit) respectively, in addition to sonic porosity (phi). the fourth track contains water saturation. the fifth track represents the rock constituents (fluids, minerals, and porosity). the proposed method models are represented in the third track where it contains the three transit time curves, the black is the sonic transit time, blue is model water transit time, and the red is model oil curve. in the top of mishrif formation, where it called upper mishrif u1, its top at 2268 m, it is a tight zone with porosity less than 8% p.u. the sonic travel time does not match with the model transit time curves, and the water and oil curves are overlaid, with less value. this behavior is obvious in each tight zone along the formation, where, this behavior is repeated in middle mishrif, it can be seen in the top of m1 from 2336 to 2339, and also in m2 zone from 2352 to 2375.5 m. this behavior can be traced back to the lower value of the porosity which is involved in both dry frame and bulk rock modulus values, where it will affect these values to a great extent. for the water zone in upper mishrif, u2 from 2295 to 2330.5, the oil model curve shows high transit time, in comparison to the sonic and model water curve, which are matched well, and gives good indication for water-bearing zone, except for 10 meters from 2302 to 2312, where the sonic tool suffered from tool malfunction and there was a problem in the data telemetry. the match between model water curve and sonic transit time is good as long as the porosity is high, where we can see the interval from 2316 to 2318 where porosity decreases the match between curves is misleading. because it shows an oil zone instead of water due to the match is more to oil curve than for the water one. for the marl zone, from 2331 to 2336 m, where it composed of 40% calcite, and 60% clay minerals. where the gamma ray curve reads an average around 100 gapi, which is the cap-rock of the reservoir. the curves show no match at all, due to the tool erroneous readings as the hole suffered from severe washout, as the caliper log reads 17 inches’ enlargement, while the bit size is 8.5 inches that cause the sonic tool to shows abnormal readings. for the model, the two curves of oil and water, both show abnormal behavior, due to that the density and neutron readings are highly affected by the washout, so the porosity is overestimated and wrapped more than 0.50 p.u., which is not a real case, thus it has contributed to the model as a wrong value, in addition to the sonic log abnormal values. for the oil zones below, m1, from 2336 to 2352, is the first oil-bearing zone, it has fair reservoir characteristics, the top of m1 from 2336 to 2339 it is a tight zone of porosity less than 0.02 p.u. the behavior of curves is similar to u1 and m2, where the two model curve show low transit time values and overlies. from 2339 to 2352 it is fair in characteristics of water saturation around 52% average, and porosity of about 0.21 p.u. the model oil curve is well matched with the sonic transit time, while the model water shows lower values and there is a clear separation between water and oil curves, which indicates oil-bearing zone. m. j. al-khafaji and w. m. al-kattan / iraqi journal of chemical and petroleum engineering 20,1 (2019) 53 – 64 48 for l1.1 reservoir, from 2358 to 2360.8 it shows a good match between sonic transit time and model oil curve, and from 2360.8 to 2362, a tight streak shows the same behavior for other tight zones. for the main pay zone of l1.2 from 2362.5 to 2400, it shows an excellent match between sonic curve and model oil curve a very clear separation between them and that of model water curve which displays lower transit time values. and for l2 reservoir where it composed of two systems; oil from 2400 to 2412.9, where the owc from open hole conventional interpretation is at 2412.9, and water from 2412.9 to total depth. in this zone, the oil saturation increases from 60% to 100%, which indicates it is the transition zone of the reservoir. the match is still a good and clear separation between the water and the oil curves. and the owc from a model is at 2413.8 with an error value of 0.03%. the sudden change in curve matching from oil to water, as traced back to the model itself, as the fluid properties are involved in two separate curves, each one represents different pore fluid, and that is the reason why there is no gentle change from oil to water in the transition zone. the rest of l2 is water-bearing zone, where the sonic and model water curve are matched well. 8conclusion 1the ramamoorthy and murphy method is a valuable non-conventional method to detect the type of pore fluid within the area of study. 2the method relies on the gassmann theory, so it follows all gassmann theory assumptions. 3the lithology type needs to be known, in order to use the appropriate solid matrix parameters. 4the dry frame bulk modulus correlation used in the original method proposed by the previous authors, didn’t give a good prediction for the study area chosen in this study, another correlation has been chosen, which is depends on porosity value and velocity ratio gave more acceptable results. 5the model in the tight zones of the reservoir showed similar behavior in all of these zones along the openhole section. while, in clay-rich zones such as marls or shales, the model gave erroneous results due to raw sonic and porosity logs are highly affected by the washout of these intervals. 6the model is a highly predictive tool in the oil and water zones of high porosity greater than 0.1 p.u., the model oil curve is matching sonic transit time along the oil zone with a clear separation between oil and water curves, and that separation increases in the good reservoir characteristics zones and less in poor characteristics zones. hence, separation increases with increasing characteristics. 7the method applicability in the study area is good after modification regarding the properties of rock and fluids. 8as suggested by original authors it can be used as an assistant tool independent from conventional methods that rely on resistivity tools, in exploration wells. and also it can be used in time-lapse monitoring of the reservoir, after water flooding to monitor the breakthrough from sonic log only. thus it is a low cost good predictive tool. nomenclatures ∆tp: compressional transit time, μsec/ft. ∆ts: shear transit time, μsec/ft. bo: oil fvf, bbl/stb. g: rock shear modulus, gpa. kb: rock bulk modulus, gpa. kfl: fluid bulk modulus, gpa. kfr: dry frame bulk modulus, gpa. kma: matrix bulk modulus, gpa. nphi: neutron porosity, fraction. p: formation pressure, mpa, rg: gas oil ratio, l/l. s: salinity, (ppm/1000000). t: formation temperature, celsius. vbrine: sound velocity in brine, ft/sec. voil: sound velocity in oil, ft/sec. vp: compressional velocity, ft /μsec. vs: shear velocity, ft /μsec. vw: sound velocity in fresh water, ft/sec. γgas: gas gravity, unitless. ρ’o: oil density @reservoir cond., gm/cc. ρb: rock bulk modulus, gm/cc. ρbrine: brine density @reservoir cond., gm/cc. ρoil: oil density @surface, gm/cc. ρp&t: oil density corrected for p&t, gm/cc. ρp: oil density corrected for pressure surface, gm/cc. ρw: fresh water density @reservoir cond., gm/cc. φt: φt: total porosity, fraction. references [1] r. ramamoorthy and w. f. murphy, “fluid identification through dynamic modulus decomposition in carbonate reservoirs,” paper q in 39th annual logging symposium transactions: society of professional well log analysts, 1998. [2] w.w. souder, “using sonic logs to predict fluid type,” society of petrophysicists and well-log analysts, 1 sep. 2002. [3] e. fjær, r. m. holt, a. m. raaen, and r. risnes, “chapter 5 elastic wave propagation in rocks,” in petroleum related rock mechanics, vol. 53, elsevier, 2008, pp. 175–218. [4] j. w. minear and c. r. fletcher, “full-wave acoustic logging,” spwla 24th annual logging symposium. society of petrophysicists and well-log analysts, 1983. [5] m. r. wyllie, a. r. gregory, and l. w. gardner, “elastic wave velocities in heterogeneous and porous media,” geophysics, vol. 21, no. 1, jan. 1956. [6] o. serra, the acquisition of logging data, elsevier, 1985. [7] a. m. aqrawi, j. c. guff, a. d. horbury, and f. n. sadooni, petroleum geology of iraq, vol. 1, 1 vols. aberystwyth, uk: scientific press ltd., 2010. [8] s. z. jassim and t. buday, “units of stable shelf.,” in geology of iraq, 1st ed., brno, czech republic: dolin, 2006, pp. 57–70. https://www.onepetro.org/conference-paper/spwla-1998-q https://www.onepetro.org/conference-paper/spwla-1998-q https://www.onepetro.org/conference-paper/spwla-1998-q https://www.onepetro.org/conference-paper/spwla-1998-q https://www.onepetro.org/conference-paper/spwla-1998-q https://www.onepetro.org/journal-paper/spwla-2002-v43n5a1 https://www.onepetro.org/journal-paper/spwla-2002-v43n5a1 https://www.onepetro.org/journal-paper/spwla-2002-v43n5a1 https://books.google.iq/books?hl=en&lr=&id=l6cfasfxhzyc&oi=fnd&pg=pp1&dq=%5b3%5d%09e.+fj%c3%a6r,+r.+m.+holt,+a.+m.+raaen,+and+r.+risnes,+%e2%80%9cchapter+5+elastic+wave+propagation+in+rocks,%e2%80%9d+in+petroleum+related+rock+mechanics,+vol.+53,+elsevier,+2008,+pp.+175%e2%80%93218.+https://doi.org/10.1016/s0376-7361(09)70191-8&ots=nxtxeqway9&sig=irtb0xjlbahqkoouyh0culbt_qk&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=l6cfasfxhzyc&oi=fnd&pg=pp1&dq=%5b3%5d%09e.+fj%c3%a6r,+r.+m.+holt,+a.+m.+raaen,+and+r.+risnes,+%e2%80%9cchapter+5+elastic+wave+propagation+in+rocks,%e2%80%9d+in+petroleum+related+rock+mechanics,+vol.+53,+elsevier,+2008,+pp.+175%e2%80%93218.+https://doi.org/10.1016/s0376-7361(09)70191-8&ots=nxtxeqway9&sig=irtb0xjlbahqkoouyh0culbt_qk&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=l6cfasfxhzyc&oi=fnd&pg=pp1&dq=%5b3%5d%09e.+fj%c3%a6r,+r.+m.+holt,+a.+m.+raaen,+and+r.+risnes,+%e2%80%9cchapter+5+elastic+wave+propagation+in+rocks,%e2%80%9d+in+petroleum+related+rock+mechanics,+vol.+53,+elsevier,+2008,+pp.+175%e2%80%93218.+https://doi.org/10.1016/s0376-7361(09)70191-8&ots=nxtxeqway9&sig=irtb0xjlbahqkoouyh0culbt_qk&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=l6cfasfxhzyc&oi=fnd&pg=pp1&dq=%5b3%5d%09e.+fj%c3%a6r,+r.+m.+holt,+a.+m.+raaen,+and+r.+risnes,+%e2%80%9cchapter+5+elastic+wave+propagation+in+rocks,%e2%80%9d+in+petroleum+related+rock+mechanics,+vol.+53,+elsevier,+2008,+pp.+175%e2%80%93218.+https://doi.org/10.1016/s0376-7361(09)70191-8&ots=nxtxeqway9&sig=irtb0xjlbahqkoouyh0culbt_qk&redir_esc=y#v=onepage&q&f=false https://www.onepetro.org/conference-paper/spwla-1983-ee https://www.onepetro.org/conference-paper/spwla-1983-ee https://www.onepetro.org/conference-paper/spwla-1983-ee https://www.onepetro.org/conference-paper/spwla-1983-ee https://library.seg.org/doi/abs/10.1190/1.1438217 https://library.seg.org/doi/abs/10.1190/1.1438217 https://library.seg.org/doi/abs/10.1190/1.1438217 https://books.google.iq/books?hl=en&lr=&id=k6k6ha14yvqc&oi=fnd&pg=pp1&dq=the+acquisition+of+logging+data,&ots=vbo6n8g_gx&sig=ebbr10-huuizaqfxekp_ssyd-cw&redir_esc=y#v=onepage&q=the%20acquisition%20of%20logging%20data%2c&f=false https://books.google.iq/books?hl=en&lr=&id=k6k6ha14yvqc&oi=fnd&pg=pp1&dq=the+acquisition+of+logging+data,&ots=vbo6n8g_gx&sig=ebbr10-huuizaqfxekp_ssyd-cw&redir_esc=y#v=onepage&q=the%20acquisition%20of%20logging%20data%2c&f=false m. j. al-khafaji and w. m. al-kattan / iraqi journal of chemical and petroleum engineering 20,1 (2019) 53 – 64 56 [9] m. embong, m. higashi, h. h. abu bakar, k. a. zamri, f. h. m ali, s. moriya, s. b. m said, and a. t. patrick panting, “petroleum geoscience conference & exhibition2012,” in reservoir characterisatioin of mishrif formation of garraf field, iraq, using 3d seismic and ai inversion, 2012. [10] z. wang, w.k. hirsche, and g. sedgwick, “seismic velocities in carbonate rocks,” journal of canadian petroleum technology, pp. vol. 30, no.2, pp. 112 – 122, march-april, 1991. [11] j.h. sch n, physical properties of rocks, 2nd ed., vol. 65. amsterdam, netherlands: elsevier, 2015. [12] d. v. ellis and j. m. singer, well logging for earth scientists, 2nd ed. springer, 2007. [13] d. han and m. batzle, “constrained and simplified gassmann’s equations.,” society of exploration geophysicists, pp. 1837–1841, 2002 [14] g. mavko, j. dvorkin, and t. mukerji, the rock physics handbook: tools for seismic analysis of porous media. cambridge, uk: cambridge university press, 2009. [15] j. e. white, underground sound: application of seismic waves, 1st ed. amsterdam: elsevier, 1983. [16] n. al-khateb, “a look into gassmann’s equation,” in geoconvention2013, calgary, canada, 2013. [17] a. e. h. love, a treatise on the mathematical theory of elasticity, 4th ed. ny: dover publications, pp. 103–294, 1944. [18] m. batzle and z. wang, “seismic properties of pore fluids,” geophysics vol. 57, pp. 1396–1408, 1992. [19] z. wang, m.l. batzle, and a. nur, 1990, “effect of different pore fluids on seismic velocities in rocks,” can. j. expi. geophys., vol. 26, pp. 104-112. 1990. [20] v. saxena, “fresh sonic interpretation in limestone through modulus decomposition,” society of petroleum engineers, new delhi, india, 1998. [21] g.r. pickett, “acoustic character logs and their applications in formation evaluation,” society of petroleum engineers, usa, 1 jun. 1963. https://www.onepetro.org/journal-paper/petsoc-91-02-09 https://www.onepetro.org/journal-paper/petsoc-91-02-09 https://www.onepetro.org/journal-paper/petsoc-91-02-09 https://www.onepetro.org/journal-paper/petsoc-91-02-09 https://books.google.iq/books?hl=en&lr=&id=uckhbgaaqbaj&oi=fnd&pg=pp1&dq=j.h.+scho%cc%88n,+physical+properties+of+rocks,+2nd+ed.,+vol.+65.+amsterdam,+netherlands:+elsevier,+2015.&ots=razvuataym&sig=5qwj-uwvuty6dbpfzfgbut4u2_w&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=uckhbgaaqbaj&oi=fnd&pg=pp1&dq=j.h.+scho%cc%88n,+physical+properties+of+rocks,+2nd+ed.,+vol.+65.+amsterdam,+netherlands:+elsevier,+2015.&ots=razvuataym&sig=5qwj-uwvuty6dbpfzfgbut4u2_w&redir_esc=y#v=onepage&q&f=false https://link.springer.com/book/10.1007%2f978-1-4020-4602-5 https://link.springer.com/book/10.1007%2f978-1-4020-4602-5 https://library.seg.org/doi/abs/10.1190/1.1817044 https://library.seg.org/doi/abs/10.1190/1.1817044 https://library.seg.org/doi/abs/10.1190/1.1817044 https://books.google.iq/books?hl=en&lr=&id=2yzcyuqeqskc&oi=fnd&pg=pr1&dq=%5b14%5d+g.+mavko,+j.+dvorkin,+and+t.+mukerji,+the+rock+physics+handbook:+tools+for+seismic+analysis+of+porous+media.+cambridge,+uk:+cambridge+university+press,+2009.&ots=peomdopohi&sig=kx4jtxzxddjtopdertm7qx2gmck&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=2yzcyuqeqskc&oi=fnd&pg=pr1&dq=%5b14%5d+g.+mavko,+j.+dvorkin,+and+t.+mukerji,+the+rock+physics+handbook:+tools+for+seismic+analysis+of+porous+media.+cambridge,+uk:+cambridge+university+press,+2009.&ots=peomdopohi&sig=kx4jtxzxddjtopdertm7qx2gmck&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=2yzcyuqeqskc&oi=fnd&pg=pr1&dq=%5b14%5d+g.+mavko,+j.+dvorkin,+and+t.+mukerji,+the+rock+physics+handbook:+tools+for+seismic+analysis+of+porous+media.+cambridge,+uk:+cambridge+university+press,+2009.&ots=peomdopohi&sig=kx4jtxzxddjtopdertm7qx2gmck&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=2yzcyuqeqskc&oi=fnd&pg=pr1&dq=%5b14%5d+g.+mavko,+j.+dvorkin,+and+t.+mukerji,+the+rock+physics+handbook:+tools+for+seismic+analysis+of+porous+media.+cambridge,+uk:+cambridge+university+press,+2009.&ots=peomdopohi&sig=kx4jtxzxddjtopdertm7qx2gmck&redir_esc=y#v=onepage&q&f=false https://ci.nii.ac.jp/naid/10012947553/ https://ci.nii.ac.jp/naid/10012947553/ https://library.seg.org/doi/abs/10.1190/1.1443207 https://library.seg.org/doi/abs/10.1190/1.1443207 https://library.seg.org/doi/abs/10.1190/1.1443207 https://ci.nii.ac.jp/naid/10007502229/ https://ci.nii.ac.jp/naid/10007502229/ https://ci.nii.ac.jp/naid/10007502229/ https://www.onepetro.org/conference-paper/spe-39542-ms https://www.onepetro.org/conference-paper/spe-39542-ms https://www.onepetro.org/conference-paper/spe-39542-ms https://www.onepetro.org/conference-paper/spe-39542-ms https://www.onepetro.org/journal-paper/spe-452-pa https://www.onepetro.org/journal-paper/spe-452-pa https://www.onepetro.org/journal-paper/spe-452-pa m. j. al-khafaji and w. m. al-kattan / iraqi journal of chemical and petroleum engineering 20,1 (2019) 53 – 64 56 appendix a: garraf oilfield lithological column, after ref [7] m. j. al-khafaji and w. m. al-kattan / iraqi journal of chemical and petroleum engineering 20,1 (2019) 53 – 64 56 appendix b: fluid elastic properties table 2. oil properties zone m1 l1.1 l1.2 api@15 °c 24.06 24.35 25.37 p (mpa) 20.898 23.814 23.263 t (°c) 79.7 77.8 79 d e a d o il ρo (g/cc) 0.9096 0.9079 0.902 ρo @p (g/cc) 0.9202 0.92 0.914 ρo @t (g/cc) 0.8724 0.8738 0.8671 vo ft/s 4598.53 4685.94 4648.7 ko (gpa) 1.71385 1.78244 1.7408 l iv e o il γg 0.938 0.943 0.946 rg (l/l) 119 143.13 143.37 bo (rb/stb) 1.3914 1.4645 1.469 ρ’o (g/cc) 0.7842 0.712193 0.623093 k,(gpa) 1.5406 1.4528 1.251 table 3. water properties studied well brine zone t (°c) p (mpa) ppm/10 -6 ρw (g/cc) ρbr@p (gm/cc) vw (m/s) vbr (ft/s) kw (gpa) khasib 76 20.753 0.0998 1 1.0688 1598.65 5528.5 3.0353 u1 77.3 20.864 0.1 1 1.0688 1598.77 5528.3 3.0351 u2 78 21.057 0.1 1 1.0688 1598.8 5527.8 3.0346 marl 77.8 21.512 0.11 1 1.0689 1598.8 5556.8 3.0665 l2 79.4 23.539 0.114 1 1.069 1598.82 5566.3 3.0771 m. j. al-khafaji and w. m. al-kattan / iraqi journal of chemical and petroleum engineering 20,1 (2019) 53 – 64 56 appendix c: well log interpretation along with the proposed model curves m. j. al-khafaji and w. m. al-kattan / iraqi journal of chemical and petroleum engineering 20,1 (2019) 53 – 64 55 إستخدام الخواص المرنة لمصخور كأداة تنبؤية لنوع المائع في مسامات الصخور الكاربونية الخالصة إنَّ اليدف من ىذه الدراسة، ىو لفحص تطبيق طريقة تبؤية لنوع المائع المسامي المنشورة من قبل رامامورثي األوسط الكاربونية. وكذلك تضمنت إستخدام نتائج ساودر الذي إستخدم مبدأ ومورفي، إلحدى تكوينات الشرق مورفي في توقع نوع المائع المسامي في صخور بحر الشمال الطبشورية. ولقد تناولت ىذه الدراسة -رامامورثي تكوين المشرف في حقل الغراف الواقع في جنوب العراق، من خالل بئر شبو عمودي محفور إلى تكوين شرف. وقد إستخدمت بيانات المجسات في التكوين المفتوح وخصوصا المجس الصوتي ذو الطورين )القصي الم ( لغرض pvtواإلنضغاطي( وبيانات الوصف الجيولوجية وبيانات الفحوصات المختبرية لمسوائل المكمنية ) مجس الكثافة و قياسات سرعة إشتقاق الخواص المرنة ليذه الموائع بإستخدام معادالت باتزل ووانغ. تم إستخدام متر( عمى طول التجويف. أما معامل اإلنضغاطية 4.21.0القص إلشتقاق معامل القص لمصخرة لكل ) لمصخرة الجافة فقد تم إشتقاقو من معادلة ساكسينا، بدال عن المعادالت المتبعة في الدراستين السابقتين بسبب نوع المسامية. تم إستخدام معادلة غاسمان لحساب معامل الحاجة إلى دراسة تفصيمية لمباب لغرض معرفة % نفط(، وتم ربطيا بمعادالت لوف 244% ماء( و)244اإلنضغاطية الكمي لمصخرة بظروف تشبع مختمفة ) إلشتقاق قيمة زمن اإلنتقال األنضغاطي )مقموب السرعة( بإستخدام المعامالت الناتجة من معادلة غاسمان. بعد نيات الناتجة مع منحنى المجس الصوتي اإلنضغاطي وكذلك مع تفسير التجويف المفتوح من ذلك تم دمج المنح مسامية وتشبع وصخارية. وقد بينت الدراسة إن الطريقة ىي دليل جيد عمى نوع المائع المسامي، وخصوصا في النتائج متوافقة بشكل مناطق المسامية الجيده. وبعكسو في المناطق القميمة النفاذية فيي غير مفيده. وقد كانت الماء بشكل ممتاز ومشابو لمعمق الناتج من منحنى -ممتاز مع التفسيرات األخرى، فقد أعطت عمق تماس النفط %(.4.40التشبع الناتج من المقاومة النوعية العميقة، بيامش خطأ اقل من ) ijcpe vol.9 no.1 (march 2008) 51 iraqi journal of chemical and petroleum engineering vol.9 no.1 (march 2008) 51-56 issn: 1997-4884 preparation of zeolite type 13x from locally available raw materials jalil .r.ugal*, malik mustafa** and ali.a.abdulhadi * chemistry departmentcollege of science for womenuniversity of baghdad – iraq ** biology department -college of alkhawarizmi engineeringuniversity of baghdad – iraq abstract the aim of this work was to prepare zeolite type 13x from locally available kaolin and to study the effects of using some binding materials through the process of agglomeration of this zeolite. this study was focused on using kaolin binder in different weight percents (10,15,25,35 and 45%).physical and mechanical properties of the agglomerates such as porosity , apparent density , pore volume, crushing strength , loss on attrition , surface area and finally the adsorption capacity had been measured and evaluated .the preparation step was achieved by mixing the reactants consisting of metakaolin , source of silica as ( sodium trisilicate ) and sodium hydroxide . the conditions was temperature of 70° c and time of mixing as 8, 10,24,34,50,65,75 and 80 hours .the zeolite –binder was shaped in the form of cylindrical particles of 2.5 mm in diameter and 4-8 mm long using a suitable experimental technique . it was found that the suitable binder kaolin clay with 25% by weight. this gave the best properties as crushing strength, adsorption capacity and density compared with standard properties of zeolite 13x. keywords: zeolite 13x, kaolin binder, agglomeration process. introduction zeolites are crystalline, hydrated aluminosilicate with a negative charge framework structure containing holes occupied by large ions and water molecules that have substantial freedom of movement. this leads to possibities of ion exchange and reversible dehydration[1]. two types (x) and (a) are most important. their significance as commercial adsorbents depends on the fact that each crystal contains interconnecting cavities of uniform size , separated by narrow opening , or pores of three-dimensional framework structure. when formed, this crystalline network is full of water. this moisture can be driven from the cavities with moderate heating without changing the crystalline structure [2]. after dehydration, the zeolite is termed activated and the pores or channels may be filled with water or other materials [3]. the framework of x-type zeolite consists of a tetrahedral arrangement of sodalite units or truncated octahedron (each sodalite unite has six square faces of oxygen atoms and eight hexagonal faces or hexagonal faces by a hexagonal prism into a super structure to form x zeolite , [4]. the main cavities in the structure of x –zeolite are nearly spherical (elliptical) in shape and are about (13°a) diameter called supercages. these cavities are entered by way of channels (8-9 ° a) in diameter .the truncated octahedron has smaller cavities, the center being a bout (6.6°a) in diameter with entrance through the hexagonal face of about (2.2°a) [5]. zeolites type 13x, in which the negative framework (high aluminum content) charge is balanced by the appropriate number of cations, electrostatic interactions. university of baghdad college of engineering iraqi journal of chemical and petroleum engineering preparation of zeolite type 13x from locally available raw materials ijcpe vol.9 no.1 (march 2008) 52 this favors adsorption by this zeolite of substance with a large dipole moment (e.g. .h2o, nh3, h2s, and so2) or quadruple moment (n2, co and co2) [6, 7]. therefore if two molecules are capable of entering into a single zeolite system, the zeolite retains one preferentially to all other on the basis of some other zeolite interactions such as polarity, the molecule with strong degree of polarity being preferentially retained [8]. high purity zeolite crystals used in adsorption processing must be formed in agglomerates having high physical strength and attrition resistance. the crystalline powders are formed into agglomerates by the addition of an inorganic binder, generally clay, in wet mixture .the blended clay –zeolite mixture is extruded into cylindrical-type pellets, spherical or granulated [9]. agglomeration is the process of making big particles from little ones. when fine particles, usually in a moist state, are brought into intimate contact through agitation, binding forces come into action to hold the particles together as agglomerate .capillary binding caused by wetting with water or aqueous solutions is the most common binding mechanism [10]. experimental work this study is aimed to prepare zeolite type 13xwith different weight percent of kaolin binder (10, 15, 25, 35 and 45%wt) .the reaction time was also studied (10, 24,34,50,60 and 80 hours) .the experimental part of this work is consisted of two basic steps 1. preparation of zeolite 13x from local materials (i.e.kaolin) and study the effect of mixing time on the preparation process at 70°c. 2. agglomeration of the prepared samples using kaolin binder material and study the main properties of the agglomerates. materials the used kaoline is available in al–dewekhala quarry in al-anbar region. sodium silicate was supplied by fluka chemia, and sodium hydroxide was supplied from bdh (england). preparations of zeolite 13x the preparation of sodium type zeolite 13x was carried out by the addition of (9%wt) sodium hydroxide solution to the metakaolin and sodium trisilicate mixture. the reactant mixture has a composition expressed in terms of oxide mole ratio of: sio2 /al2o3 na2o/sio2 h2o/na2o 4 1 40 the temperature of reaction 70° c and mixing time ranged from 8 to 80 hours. in each experiment, metakaolin and sodium trisilicate were mixed together with sodium hydroxide solution in a two-necked round bottom flask. the agitation was achieved using a variable speed stainless steel paddle type mixer with a relatively medium revolution driven motor (voss instrument ltd .type sg/pa/st). heating the flask was achieved using an electrical mantle heater, while the temperature of the mixture in the heated flask was controlled using variable input voltage. the next steps were, decantation, washing several times with distilled water until the ph value reachs to 10, ph value was measured by a ph meter (metrohm 605). the product then was filtered in bukhner funnel with the aid of a vacuum pump (type edward vacuum pump model eim5, serial 0146g) and dried at 120°c for 12 hours (11) using an electric oven (tecnoformal ltd., max .temp. 250° c) . after drying zeolite was converted to a fine divided powder using centrifuge ball mill (type retch, s2) provided with seven steel balls. the general steps in the preparation process are summarized in the following fig.. schematic diagram for the preparation of zeolite 13x agglomeration procedure the general steps for the preparation of zeolitebinder agglomerates are illustrated in following fig.. dry zeolite powder was added to the binding material. it has a size of 45 micron. this particle size was found optimum and offered better porosity, adsorption capacity, strength and reasonable loss on attrition for the shaped bodies [12-14]. different amount (10, 15, 25, 35 and 45 wt %) of kaolin binder are mixed mechanically with the corresponding amounts (90, 85, 75, 65 and 55 wt) of the zeolite powder. samples prepared are shown in table 1. jalil et al. ijcpe vol.9 no.1 (march 2008) 53 table 1 samples identification binder content wt % 45 35 25 15 10 binder type 5 4 3 2 1* kaolin * sample no.1 block diagram for the preparation of zeolite-binder agglomerates mixing of wet powders was carried out manually using the spatula after the addition of the appropriate amount (28-42 wt %) of water, as a binder plasticizer to the dry mixture in order to assist the mixing .if water content was low, the material would agglomerate poorly or would not agglomerate at all .on the other hand, if water content was high, the particles would not stick together. shaping shaping process was done after the paste was formed. the paste was placed in a cylindrical cavity of 2 cm inside diameter and 10 cm long and it ended with a die of 2.5 mm diameter. pellets were obtained when the paste was compressed manually. very uniform spaghetti shaped paste was ejected and put in a porcelain crucible at room temperature overnight. drying pellets were dried in an electrical oven (tecnoformal ltd., max. temp. 250° c) at 120° c for 2 hours [12,14]. this allowed the removal of water from the whole surface of pellets. calcination the cylindrical pellets were calcined using a programmable electrical furnace (model n2o /h, max .temp.1340° c) at 650° c for 2 hours [12, 13, 15], then the calcined pellets were cut into pieces (4-8) mm long. physical properties: porosity, density, and pore volume the porosity of the pellet adsorbent particles is determined by using the water impregnation method. the apparent or bulk density can be also determined by using the water impregnation method [16]. the pore volume of voids for the pellet adsorbent particles are calculated in the present work from the amount of absorbed water on the assumption that the water is present as the normal liquid , by using the following equation [17]: da x v s p  (1) where: vp is the pore volume, xs is the quantity of adsorbed water per unit mass of adsorbent, and da is the density of water. adsorption capacity measurement adsorption capacity of the prepared samples was tested using the gravimetric method, which measures the amount of gas or vapor adsorbed by weighing the sample in the system on a balance [9, 18]. the test was carried out in the albasil company. the procedure was as follows; an amount of the sample under testing was dried at 100° c using a mantle heater, cooled and weighed. the system was first evacuated then compressed air was allowed to pass through trap 1 containing water inside .then humid air was passed over the tested sample , present in trap 2 . mechanical properties crashing strength the radial crashing strength of the pellets was done by using a compression force within (0220) newton. the value of the force exerted on the pellet until it crushed was recorded. ten pellets of each sample were tested and an average value was taken [19]. attrition test the most widely used test for measuring losses by attrition is the ball mill test [16, 20]. the attrition value for each sample is calculated as the percentage loss by the attrition as follows [21]: (2) preparation of zeolite type 13x from locally available raw materials ijcpe vol.9 no.1 (march 2008) 54 results and discussion chemical analysis of zeolite the chemical composition of zeolite 13x prepared in the present work is given in table (2) (the analysis was conducted in the company of geological survey and mining). the ratio of sio2 to al2o3 was calculated as mole ratio and was equal to 2.48 .breck [9], rabo [22] and howell [23] had reported that this ratio lies between (2-3) for the same type zeolite 13x .hence the obtained results were in good agreement with those reported by breck [9]. also, there appeared that there were small amounts of impurities like anatase (tio2), hematite (fe2o3) periclas (mgo) and cao. table 2 chemical analysis of prepared zeolite type 13x weight (%) constituent 38.54 sio2 26.42 al2o3 14.8 na2o 0.636 cao 1.74 fe2o3 0.083 mgo 3.02 tio2 0.07 k2o 12.45 l.o.i effect of mixing time and reaction temperature on the synthesis of zeolite 13x content fig. 1 shows the effect of 70° c reaction temperature and the mixing time on the preparation of zeolite 13x .at 70° c, the zeolite formation started after 34 hours from the beginning of the reaction, and the content of zeolite 13x increased with increasing time. fig. 1 the effect of mixing time and reaction temperature on the content of zeolite 13x the effect of binder content on the optimum h2o content the optimum amount of water added to each amount of binder used is so important to control the formation of the pellet particles since water facilitates the cohesion between solid particles. the best amount of added water was obtained by visual inspection of the paste. fig. 2 shows that the optimal water ratio added to the mixture of zeolitebinder decreases with increasing of kaolin binder. it seemed that this material was saturated with less amount of water .the ability of kaolin to adsorb water is due to its crystals that consists of one dimension and single layer of silicon sheet . fig. 2 optimum water content for the agglomeration of zeolite 13x effect of binder content on porosity, pore volume and density fig.s 3 and 4 show the effect of the binder amount on the porosity and pore volume respectively. fig. 3 the effect of binder content on the porosity of pellets of zeolite 13x it is shown that with increasing the binder amount, the porosity and pore volume decreases .this is due to the decreasing in the porous media (i.e. ., decrease in the quantity of micropores). the decrease in the porous media resulted from the sintering of the fines and the combination of semimolten impurities during thermal treatment of clay, which causes blockage of the micropores [9]. fig. 5 shows the bulk density increased as the kaolin binder content increased. this behavior is attributed to the high binding power of binder because zeolite particles will adhere by the binder and arrange themselves to form jalil et al. ijcpe vol.9 no.1 (march 2008) 55 a dense packing leading to an increase in the bulk density by solid bridges. fig. 4 the effect of binder content on the pore volume of pellets of zeolite 13x fig. 5 the effect of binder content on the apparent density of zeolite 13x effect of binder content on adsorption capacity fig. 6 shows that the adsorption capacity decreased by increasing the binder content. the higher values of the adsorption capacity were obtained for the pellets of zeolite having the lowest weight percent of kaolin binder (10%). this is attributed to the three dimensional frameworks of zeolite that have high ability to adsorb polar molecules causing them to be high capacitance for water molecules. the decreasing of adsorption capacity with increasing the amount of kaolin binder is attributed to the increasing of sintering due to the increase in the proportions of kaolin, leading to occlude the microporous channels in the structure of pellets. it may be also attributed to the fine colloids of the kaolin, which adhere to the surface of zeolite crystals interrupting the adsorption process [9]. effect of binder content on mechanical properties fig.s 7 and 8 illustrate the effect of kaolin binder amount (weight %) on the crushing strength and percentage weight loss by attrition, respectively. these figures show that with increasing the binder amount in the mixture, the crushing strength of the extrudate particles gradually increases and the percentage loss by attrition decreases. fig. (6) the effect of binder content on the adsorption capacity of water vapor on zeolite 13x fig. 7 the effect of binder content on the crushing strength of pellets of zeolite 13x fig. 8 the effect of binder content on the attrition resistance of pellets of zeolite 13x it is clear that kaolin as binders with 45% by weight have the highest strength and the smallest weight loss by attrition .this is attributed to the high binding power of this plastic clay and high cohesion when dried and calcined [18].the plasticity of the kaolin clay is attributed to the proportion of the colloidal gel matter present .it will concentrate the liquid bridges especially at the contact points and on the contact surfaces of the zeolite particles .during drying , the gel concentrated there dry up and form solid mortar bridges .this contributes to preparation of zeolite type 13x from locally available raw materials ijcpe vol.9 no.1 (march 2008) 56 increasing the mechanical properties of the extrudates .also, when the proportion of clay increases, the sintering increases, leading to an increase in the mechanical properties of extrudates because zeolite particles are held together by strong bonds resulting from sintering of the minor kaolin clay particles [10]. effect of binder on surface area measurement the surface area of pellets decreased with increasing the kaolin binder content. table 3 shows the surface area for some selected samples of the prepared zeolite 13x .the surface area measurements were conducted by ibn sina company. the increase in the binder content causes the grains to become closer, thus decreasing the surface area of the zeolite pellets. table 3 surface area for some selected samples of prepared zeolite surface area m  /g binder 530.2 10%kaolin 470.1 25%kaolin 370.0 35%kaolin references 1. james, t.richardson ", principles of catalyst development ", (1989). 2. behrens, p", .mesoporous inorganic solids ", advanced materials, vol .15, 127, (1993). 3. hersh , c.k ",.molecular sieves " , 22, (1961). 4. andersons, r.a.and sherman, j.d., aiche, symposium series, vol.80, (1984). 5. alex, g.o.,j.oil and gas , 84(1972). 6. eckehart , r.p",.zeolites ", ullman,s encyclopedia of industrial chemistry , vol.a28, (1966). 7. barrere , r.m.,british chem.eng ., 267(1959). 8. clark , g.,j.industrial , 21, (1980) . 9. breck , d. w ", . zeolite molecular sieves structure chemistry and use " , chapts .1,2,3,4,8 and 9 , john wiley and sons , new york , (1974). 10. kirk – othemer " , encyclopedia of chemical technology " , vol.21, john wiley and sons , new york , (1983). 11. bosch , p., ind .eng . chem.prod .res .devel ., vol.22, 401, (1983). 12. zeki , n.s" ,. preparation of zeolitesz 3a and 5a from locally available raw materials and their extrusion with different binders ", m. sc. thesis , university of baghdad , (2000) . 13. majeed , n.s" , . rotary disk spherical granulation of prepared zeolite and experimental study of the factors affecting granules size and properties ", m. sc .thesis , university of baghdad , (1999) . 14. bashir , b.n" , . preparation of zeolite – binder agglomerates from locally available raw materials as cylindrical pellets " , m.sc. thesis , university of baghdad , (1997). 15. flank , w.h . fethke , w.p .  and peeksill , m ." process for producing molecular sieve bodies " , us patene , 4, 818 , 508 , (1989) . 16. satterfield , c.n ., " heterogeneous cataysis in practice " , chem .eng . ser ., (1980). 17. linsen , b.g" , . physical and chemical aspects of adsorbents and catalysis " , academic press , london and new york , (1970). 18. urano , k ., environ , sci . tech ., vol . 16 , 1 , (1982). 19. alfred , b. searle and rex , w.grimshow " , the chemistry and physics of clay and other ceramic materia " , interscience publishing , 3rd ed ., new york , (1959) . 20. dart , j.c" ,. standardization of catalyst test methods " , aiche symposium series , vol .70 , 143 , (1974). 21. astm " , annual book of astm standards " catalysts , d4058 – 81 and d4179 – 82 , (1986) . 22. rabo , j .a " , . zeolite chemistry and catalysis " , am .chem . soc ., 34 , (1976 ). 23. howell , p.a" , . process for producing molecular sieve bodies " , us patent , 3, 119, 660 , (1964). iraqi journal of chemical and petroleum engineering vol.15 no.3 (september 2014) 19-26 issn: 1997-4884 environmental assessment of polycyclic aromatic hydrocarbon concentrations in air at thermal south power station of baghdad a and safauldeen adnan a. b , israa m. h. almousawi b hanshalmuthna s , a adnan h. afaj a ministry of science and technology, baghdad, iraq b department of chemistry, college of science , university of baghdad, baghdad, iraq abstract sixteen polycyclic aromatic hydrocarbons (pahs) concentrations were measured in aerosol samples collected for the period from april 2012 to february 2013 at thermal south power station of baghdad. fourty one aerosol sample were extracted with (1:1) dichloromethane and methanol using soxhlet for seventeen hour. the extraction solution was analyzed applying gc/ms. the pah concentrations outside thermal south power station were higher than those inside it, and higher in summer season than in winter. naphthalene, pyrene, anthracene, indeno [1, 2, 3-cd] pyrene and phenanthrene were the most abundant pahs detected in all points at the site sampling. the total polycyclic aromatic hydrocarbon (tpah) and total suspended particles (tsp) concentrations were measured during the measurement period. for individual pah compounds, the results showed a strong correlation with each other (0.998 0.77) at both sites. keywords: pahs in air, toxic pahs, analysis pah by gc-ms. introduction polycyclic aromatic hydrocarbons (pahs) form a complex class of organic compounds containing two or more fused aromatic rings, and only carbon and hydrogen atoms. the physical and chemical properties of pahs are determined by their conjugated π-electron systems, which are dependent on the number of aromatic rings and the molecular shape. the smallest member of the pah family is naphthalene, a two-ring compound, which is found in the vapour phase in the atmosphere. three to five ring-pahs compounds are found in both the vapour and particulate phases in air [1]. pahs cause mutagenic and carcinogenic activities of the metabolites of several pah compounds. the studies showed that individuals exposed by breathing or skin contact for long periods to mixtures that contain pahs can develop cancer [2-4]. in the atmosphere, pahs compounds are released as a complex mixture of compounds due to incomplete combustion of organic matter, emitted from wood burning heaters, agricultural waste burning, motor vehicle exhaust, cigarette smoke, asphalt road and roofing operations. pahs are widespread contaminants of the environment and a number of them iraqi journal of chemical and petroleum engineering university of baghdad college of engineering environmental assessment of polycyclic aromatic hydrocarbon concentrations in air at thermal south power station of baghdad 20 ijcpe vol.15 no.3 (september 2014) -available online at: www.iasj.net are either known or suspected carcinogens. benzo (a) pyrene, a widely reported five-ring pah, is known for its carcinogenic potency [5]. natural emission sources of pahs into the atmosphere include emissions from forests fires and volcanoes. some of the pahs are produced for commercial use; these include naphthalene, fluorene, anthracene, phenanthrene, fluoranthene and pyrene [6]. sensitive, rapid and accurate methods were developed to determine pahs in atmospheric particles. as highly efficient separation tools, gcms and hplc were used for analysing them [7]. in this study, aerosol samples were collected from thermal south power station of baghdad at two locations, inside the station close to the emission of pahs and outside the station located at urban area surrounding the site. sixteen pahs were determined and analyzed by gc/ms. experimental procedure 1. chemicals and standard materials methanol and dichloromethane (fluka, 99.8%) were used for extraction of pah compounds. the standard individual pahs (naphthalene, acenaphthylene, acenaphth-ene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benz(a)anthracene ,chr -ysene, benzo(b)fluoranthene, benzo(k)fluor anthene, benzo(a)pyrene, dibenz(a,h)anthracene, benzo(ghi)perylene and indeno(1,2,3cd)pyrene) were supplied by dr. ehrenstorfer company (germany) with (99.9%) purity. these compounds (mixtures or single component) are soluble in acetonitrile or methanol. 2. sampling and samples extraction aerosol samples were collected using a low volume air sampler (radeco, inc., england), which was equipped with cellulose fiber filter. cellulose filters (4.5 cm diameter, 55mm thickness from schleicher and schuell, w. germany) were preheated at 70 ◦c for 45 min prior to use to reduce their water content. before and after sampling, the cellulose filters were weighted on an electronic balance to determine the total suspended particles (tsp) and stored at low temperature in proper container until further extraction and analysis [8]. fourty one sample were collected during measurement period. sampling was done inside and outside the site twice a month for a period of 1.5 hour in the morning and evening using sniffer device (low volume air sampler). the samples were collected applying (2.0 4.0) m above ground. the ambient temperature, relative humidity (vaisala model hm1, finland) and wind rate (lambrech, england) were measured during the measurement period. after sampling polycyclic aromatic hydrocarbon were extracted in order to determine their concentrations in air samples by soxhlet apparatus using two solvents methanol and dichloromethane (1:1). soxhlet extraction was performed for 17 h. the soxhlet extractor consisted of a 250 ml round-bottom flask, 50 ml extractor and condenser with water bath; this arrangement enabled the extraction of only one filter sample at time [9, 10]. the solvents were removed to dryness using a rotary evaporator (yamato re 510) at 60 o c under gentle vacuum. the dried samples were dissolved in 5 ml methanol and the solution filtered in the micro filter (0.22 µm, minisart, sartorius stedim biotech gmbh 37070 goettingen, adnan h. afaj, muthna shanshal, israa m. h. almousawi and safauldeen adnan a. -available online at: www.iasj.net ijcpe vol.15 no.3 (september 2014) 21 germany) was put in glass container and kept at low temperature. 3. standard solution the retention time of the individual compounds (pahs) was measured with range concentration (3-334) µg/l in solvent. for the measurements, a 4point calibration range is used for all pah. the calibration ranges used are as follow: (3.33, 36.472, 67.412, and 334.215) µg/l in solvent. the target compounds pahs were identified by comparing the retention times and the mass spectra at the technology university darmstadt (tud) in germany. the final concentrations of compounds pahs were calculated from calibration curve and converted to nanogram/m 3 in air [11]. 4. gc/ ms analysis the analyses were performed using a gc-ms system (agilent technologies 5975c series gc/ msd, usa) comprising a chemstation software and auto-sampler with triple –axis detector. gas chromatography (gc) was equipped with a flame ionization detector (fid). separations were carried out using a zebron guardian, phase:zb-5ms, a non-polar, packed wih 5% phenyl methylsilox. capillary column was (l 30m × i.d. 0.25mm × df. 0.25µm). helium (99.99%) was used as carrier gas at a constant flow of 1.0 ml min −1 . the temperatures of the msd ion source and quadrupole analyzer were kept at 230°c and 150 °c, respectively. the detection limit was 1 nanogram/ liter. the injected volume was 1 μl in splitless mode. the gc temperature program for pah analysis ranged from 75 o c (hold for 3 min) to 235 o c (20 o c/min, hold for 18min), then ramped to 300 o c (15 o c /min, hold for 8 min) and the final temperature was 320 o c. the analysis time per sample was 43min [12-13]. 5. statistical analysis statistical analysis including pearson correlation analysis was performed using statistical package for social scientist (spss) version 19, and microsoft excel program. spss is a comprehensive system for analyzing data. spss can take data from almost any type of file and use them to generate tabulated reports, charts, and plots of distributions and trends, descriptive statistics, and complex statistical analysis. spss has scores of statistical and mathematical functions, scores statistical procedures, and a very flexible data handling capability. there are many functions such as descriptive statistics, contingency tables, reliability tests, pearson correlation, t-tests and anova. pearson correlation regression techniques reflect the strength of association between continues variables [14]. result and discussion fourty one sample were collected and quantified for sixteen pah compounds by gc/ms device. a single target compound compared with retention time (rt) of individual standard pahs compounds is given in table 1. the arithmetic mean and standard deviation of individual pah concentrations in inside and outside of south station in two different seasons are given in tables 2a and 2b. in summer season, the more abundance compounds were naphthalene, pyrene and anthracene (1573.5, 203.0, 127.850) ng/m 3 , respectively, while naphthalene and indeno[1,2,3cd]pyrene and phenanthrene were in winter season (36.6, 13.003,10.08) ng/m 3 , respectively. the highest concentrations of atmospheric pahs was found in the urban environment (outside) as illustrated in tables 2a and 2b, due to the increasing emission from south power station of environmental assessment of polycyclic aromatic hydrocarbon concentrations in air at thermal south power station of baghdad 22 ijcpe vol.15 no.3 (september 2014) -available online at: www.iasj.net baghdad: gas, vehicular traffic and slow dispersion of atmospheric pollutants. fig. 1 shows the variation in the individual pah concentrations. table 1: retention time of individual standard pahs compounds no. pahs / abbreviation rt min. 1 naphthalene (naph) 8.38 2 acenaphthylene (acy ) 10.42 3 acenaphthene (ace) 10.66 4 fluorene (flu ) 11.30 5 phenanthrene (phe) 12.62 6 anthracene (ant ) 12.70 7 fluoranthene (flt) 15.18 8 pyrene (pyr) 15.90 9 benzo(a) anthracene (b[a]a) 22.54 10 chrysene (chry) 22.79 11 benzo(b) fluoranthene (b[b]f) 32.45 12 benzo(k) fluoranthene (b[k]f ) 32.58 13 benzo(a) pyrene (b[a]p) 33.71 14 indeno(1,2,3-cd) pyrene (ind(cd)p) 37.93 15 dibenzo(a,h) anthracene (dba) 38.12 16 benzo(g,h,i) perylene (bghip) 39.02 the arithmetic mean and standard deviation of individual pah concentrations in inside and outside of south station in two different seasons are given in tables 2a and 2b. in summer season, the more abundance compounds were naphthalene, pyrene and anthracene (1573.5, 203.0, 127.850) ng/m 3 respectively, while naphthalene and indeno [1,2,3cd]pyrene and phenanthrene were in winter season (36.6, 13.003,10.08) ng/m 3 respectively. the highest concentrations of atmospheric pahs was found in the urban environment (outside) as illustrated in tables 2a and 2b, due to increasing emission from south power station of baghdad: gas, vehicular traffic and slow dispersion of atmospheric pollutants. figure (1) shows the variation in the individual pah concentrations. fig. 1: distribution of individual pah concentrations average total polycyclic aromatic hydrocarbon concentrations (tpah) and average total suspended particles (tsp) were measured during the period. various environmental factors, including humidity, temperature and wind rate were monitored in sites four times and the average was taken. spring season had high concentrations of tpah (2847.62) ng/m 3 , while summer season had a high concentrations of tsp (3156.21) µg/m 3 . in winter and summer seasons, temperature ranged between (15.6245.58) o c, while humidity ranged between (62.00-14.59). table (3) shows values of tpah, tsp and meteorological conditio adnan h. afaj, muthna shanshal, israa m. h. almousawi and safauldeen adnan a. -available online at: www.iasj.net ijcpe vol.15 no.3 (september 2014) 23 table 2a: average concentrations of individual pahs (ng/m 3 ) in summer season inside/morning inside /evening outside/morning outside/evening compounds mean (n=3) sd mean (n=3) sd mean (n=3) sd mean (n=3) sd naphthalene 163.185 3.815 72.580 2.920 1573.500 8.000 133.450 5.850 acenaphthylene 1.900 0.100 1.045 0.055 64.850 0.850 1.250 0.050 acenaphthene 0.995 0.005 0.650 0.050 76.005 3.505 1.700 0.100 fluorene 3.900 0.100 3.500 0.100 203.750 3.050 3.6500 0.100 phenanthrene 10.500 0.500 6.600 1.100 94.685 3.685 13.250 0.750 anthracene 19.500 0.500 1.095 0.105 127.850 3.850 23.300 0.300 fluoranthene 1.900 0.100 1.800 0.100 35.240 1.760 5.500 0.200 pyrene 2.800 0.200 5.250 0.350 203.000 3.100 14.500 1.700 benz[a]anthracene 0 0 0.150 0.050 14.500 0.500 1.150 0.150 chrysene 0 0 0.530 0.010 23.250 1.750 1.050 0.050 benzo[b]fluoranthene 0.950 0.050 0.585 0.015 24.250 0.750 0.850 0.050 benzo[k]fluoranthene 0 0 0 0 0 0 0 0 benzo[a]pyrene 0 0 0 0 25.900 0.900 0 0 indeno[1,2,3-cd]pyrene 0 0 0 0 26.600 1.600 0 0 dibenz[a,h]anthracene 0 0 0 0 0 0 0 0 benzo[ghi]perylene 0 0 0.585 0.015 45.350 2.350 0.350 0.050 table 2b: average concentrations of individual pahs (ng/m 3 ) in winter season inside/morning inside /evening outside/morning outside/evening compounds mean (n=3) sd mean (n=3) sd mean (n=3) sd mean (n=3) sd naphthalene 23.947 1.017 14.387 2.564 36.605 0.805 36.650 0.497 acenaphthylene 0 0 0 0 1.886 0.013 0 0 acenaphthene 3.792 0.142 3.657 0.050 1.599 0.002 8.427 0.446 fluorene 0.425 0.033 1.107 0.082 4.251 0.391 3.274 0.094 phenanthrene 3.865 0.065 4.211 0.394 10.018 0.089 7.780 0.602 anthracene 0.512 0.012 0.725 0.065 2.045 0.055 1.978 0.176 fluoranthene 2.399 0.056 2.537 0.006 2.067 0.069 4.628 0.225 pyrene 1.327 0.051 1.300 0.081 4.370 0.371 4.883 0.249 benz[a]anthracene 0.614 0.003 0 0 0 0 0.950 0.050 chrysene 1.005 0.005 0 0 0 0 2.2165 0.226 benzo[b]fluoranthene 4.639 0.139 2.081 0.091 1.070 0.080 3.603 0.213 benzo[k]fluoranthene 8.332 0.342 0 0 0 0 0 0 benzo[a]pyrene 3.27 0.37 0 0 1.4305 0.0405 0 0 indeno[1,2,3-cd]pyrene 13.003 2.003 1.935 0.055 2.330 0.220 3.529 0.139 dibenz[a,h]anthracene 1.057 0.067 0 0 0 0 0 0 benzo[ghi]perylene 12.519 2.619 2.589 0.101 3.652 0.102 6.254 0.264 environmental assessment of polycyclic aromatic hydrocarbon concentrations in air at thermal south power station of baghdad 24 ijcpe vol.15 no.3 (september 2014) -available online at: www.iasj.net table 3: meteorological conditions for all season and average concentrations of tsp and tpah se a so n l o c a ti o n t im e * t e m p o c h u m . % w in d r a te m /s t sp µ g /m 3 t p a h s n g /m 3 spring inside m. 34.055 25.47 0.70 226.2 1089.2 e. 33.32 24.95 1.00 244.0 2847.6 outside m. 33.28 27.76 2.90 211.6 494.86 e. 35.69 21.03 1.35 312.3 319.12 summer inside m. 42.22 16.60 0.70 3156.2 148.35 e. 45.58 14.59 1.15 437.2 66.60 outside m. 38.34 20.23 1.70 931.7 2540.3 e. 44.48 16.34 2.15 2812.6 134.7 autumn inside m. 34.17 27.08 1.00 1013.6 24.94 e. 36.17 22.88 0.80 1156.9 17.47 outside m. 29.87 34.07 0.85 1724.4 278.92 e. 35.31 23.70 1.65 1139.3 49.07 winter inside m. 21.84 43.37 0.95 409.7 47.85 e. 22.22 39.13 1.95 355.2 26.77 outside m. 15.62 62.00 0.55 375.2 63.00 e. 23.08 36.58 1.25 416.6 70.59 *m: morning, e: evening table 4: pearson correlation coefficients between the individual pah compounds compounds naph acy ace flu phen ant flut pyr naph 1 acy .870** 1 ace .793** .983** 1 flu .892** .998** .974** 1 phen .955** .929** .862** .950** 1 ant .457 .096 -.051 .155 .453 1 flut .937** .952** .902** .970** .994** .379 1 pyr .954** .926** .857** .947** .999** .458 .994** 1 b[a]ant .937** .819** .732** .847** .944** .566* .932** .948** chry .875** .982** .962** .985** .937** .161 .964** .936** b[b]flut .608* .665** .659** .664** .614* .059 .655** .618* b[k]flut -.138 -.116 -.096 -.126 -.168 -.149 -.131 -.163 b[a]p .607* .829** .870** .812** .665** -.199 .729** .663** indpyr .259 .404 .444 .388 .274 -.218 .336 .275 dib [a,h]ant -.121 -.143 -.116 -.148 -.171 -.109 -.132 -.166 b[ghi]p .562* .757** .794** .740** .601* -.196 .663** .599* continue to table 4 compounds b[a] ant chry b[b] flut b[k] flut b[a]p indpyr dib[a,h] ant b[ghi]p b[a]ant 1 chry .879** 1 . b[b]flut .743** .770** 1 b[k]flut .090 .029 .636** 1 b[a]p .649** .871** .881** .379 1 indpyr .426 .522* .908** .841** .809** 1 dib[a,h]ant .088 .004 .612* .966** .370 .805** 1 b[ghi]p .637** .823** .932** .521* .974** .895** .480 1 ** correlation at 99% confidence level. * correlation at 95% confidence level. adnan h. afaj, muthna shanshal, israa m. h. almousawi and safauldeen adnan a. -available online at: www.iasj.net ijcpe vol.15 no.3 (september 2014) 25 from table 3, it can be seen that the concentrations of tsp and tpah in winter period are less than the other periods, and this is due to heavy rain during winter period. statistical tools were applied to the pah variables (naph, acy, ace, flu, ant, phe, flut, pyr, baa, chry, bbf, bkf, bap, icdp, daha and bghip) [15]. from the results of table 4, individual pah compounds showed strong correlation with each other (0.998 0.77), due to a similar source of pah compounds emissions. the major source was incomplete combustion of fuel in the station and vehicle emission on the highway near the location of measurements. anthracene showed a negative correlation with other compounds as well as benzo[k]fluoranthene as illustrated in table 4. acknowledgments the authors wish to thank prof dr. christoph schüth, vice –dean, department of materials and geosciences, darmstadt university for permission to use gc/ms divece. the authors are very grateful to dr. tom schiedek and ms stefanie schmidt, department of materials and geosciences, darmstadt university for cooperation in the analysis of samples. references 1lao, r.c., thomas, r.s., oja, h. and dubois, l., (1973), “application of gas chromatograph-mass spectrometer-data processor combination to the analysis of polycyclic aromatic hydrocarbons and polychlorinated biphenyls”, anal. chem., 65, 338-344. 2douben p. e. t., (2003), “pahs: an ecotoxicological perspective”, john wiley and sons ltd, the atrium, southern gate, chichester, 18. 3poster d. l., schantz m. m., sander l. c., and wise s. a., (2006), “analysis of polycyclic aromatic hydrocarbons (pahs) in environmental samples: a critical review of gas chromatographic (gc) methods”, analytical and bioanalytical chemistry, 4, 386, 859-863. 4hoang l., byck s., prevost l. and scriver c. r., (1996), “pah mutation analysis consortium database: a database for diseaseproducing and other allelic variation at the human pah locus”, nucleic acids research,1, 24, 127–131. 5lee, m. l., novotny m. and bartle k.d., (1976.), “gas chromatography/mass spectrometric and nuclear magnetic resonance determination of polynuclear aromatic hydrocarbons in airborne particulates”, anal. chem., 48, 1566-1572. 6ranck, h.g. and stadelhofer, j.w., (1987), “industrial aromatic chemistry. raw products, processes, products”, berlin, springer-verlag, 308. 7delgado-saborit m., aquilina n., baker s, harrad s, and harrison r. m., (2010), “determination of atmospheric particulate-phase polycyclic aromatic hydrocarbons from low volume air samples”, anal. methods, 2, 231–242,. 8ximei h., guoshun z., yele s., and zhisheng a., (2006), “characteristics and sources of polycyclic aromatic hydrocarbons and fatty acids in pm2.5 aerosols in dust season in china”, atm. envi., 40, 3251–3262. 9ströher g. l., poppi n. r., raposo jr j. l., and souza j. b., (2007), “determination of polycyclic http://link.springer.com/search?facet-author=%22dianne+l.+poster%22 http://link.springer.com/search?facet-author=%22michele+m.+schantz%22 http://link.springer.com/search?facet-author=%22lane+c.+sander%22 http://link.springer.com/search?facet-author=%22stephen+a.+wise%22 http://link.springer.com/journal/216 http://link.springer.com/journal/216 environmental assessment of polycyclic aromatic hydrocarbon concentrations in air at thermal south power station of baghdad 26 ijcpe vol.15 no.3 (september 2014) -available online at: www.iasj.net aromatic hydrocarbons by gas chromatography — ion trap tandem mass spectrometry and source identifications by methods of diagnostic ratio in the ambient air of campo grande, brazil”, microchemical journal, 86,112– 118. 10masih a., saini r., · singhvi r., and taneja a., (2010), “concentrations, sources, and exposure profiles of polycyclic aromatic hydrocarbons (pahs) in particulate matter (pm10) in the north central part of india”, environ monit. assess, 163,421– 43. 11dejean s., raynaud c., meybeck m., and simon v., (2009), “polycyclic aromatic hydrocarbons (pahs) in atmospheric urban area: monitoring on various types of sites”, environ monit assess, 148, 27–37. 12menezes h.c. and cardeal z. l., (2011), “determination of polycyclic aromatic hydrocarbons from ambient air particulate matter using a cold fiber solid phase microextraction gas chromatography–mass spectrometry method”, j. chromatogr. a, 1218, 3300–3305. 13yus` v., quintas g., pardo o., pastor a., and delaguardia m., (2006), “determination of pahs in airborne particles by accelerated solvent extraction and largevolume injection–gas chromatography–massspectrometry”, talanta, 69, 807– 815. 14altman, d. g. and bland, j. m., (1994), “statistics notes: diagnostic tests 2: sensitivity and specificity”, bmj, 309, 102. 15callén m. s., de la cruz m. t., lópez j. m. and murillo r., (2008), “long-range atmospheric transport and local pollution sources on pah concentrations in a south europeanurban area. fulfilling of the european directive”, water air soil pollut, 190, 271–285. iraqi journal of chemical and petroleum engineering vol.9 no.4 (december 2007) 21-28 issn: 1997-4884 effect of operation conditions on catalytic oxidation of phenol in aqueous solution wadood t. mohammed * , hisham a. kadim * chemical engineering department college of engineering university of baghdad – iraq abstract this work was conducted to study the oxidation of phenol in aqueous solution using copper based catalyst with zinc as promoter and different carrier, i.e. γ-alumina and silica. these catalysts were prepared by impregnation method. the effect of catalyst composition, ph (5.6-9), phenol to catalyst concentration ratio (2-0.5), air feed rate (30-50) ml/s, stirring speed (400-800) rpm, and temperature (80-100) °c were examined in order to find the best conditions for phenol conversion. the best operating conditions which lead to maximum phenol conversion (73.1%) are : 7.5 ph, 4/6 phenol to catalyst concentration, 40 ml/s air feed rate, 600 rpm stirring speed, and 100 °c reaction temperature. the reaction involved an induction period and a steady state activity regime. both of the regimes exhibiting first order behavior with respect to the phenol concentration. the rate constants k1 and k2 for the initial rate and steady state activity regime are represented by k1=1.9×10-3 ((cm3liq/gcat) 0.5s-1 and k2= 2.4×10-10 ((cm3liq/gcat) 2 s-1) respectively. introduction the petrochemical, chemical and pharmaceutical industries produce waste waters containing organics, such as phenols, which are extremely toxic to aquatic life. it is difficult to oxidize them biologically, since biological processes are very time –consuming and operate well only in the case of relatively dilute wastes. chemical oxidation of phenolic wastes offers an alternative treatment method such as incineration (1, 2), ozonation (3, 4, 5), wet air oxidation (6, 7), photo catalyst oxidation (8,9), supercritical wet oxidation (10), aerobic coupling (11), and electrochemical oxidation (12,13). however, the sever operation conditions and the investment needed in the most cases have prevented them from being widely implemented. in the last decades, catalytic wet oxidation (cwo) using air or pure oxygen has received great attention (14-23). cwo is capable of destroying the phenolic compounds mainly yielding water and carbon dioxide or harmless product. catalytic wet oxidation is emerging as an economically and ecologically promising technique to convert refractory organized compounds, such as phenol, into carbon dioxide or harmless intermediates, which can later be treated biologically. in addition, the process can be carried out in mild pressure and temperature conditions. the purpose of this research was to study the oxidation of aqueous phenol at atmospheric pressure in detail, that is, to investigate the effects of catalyst composition, ph, phenol to catalyst concentration, air feed rate, stirring speed, temperature on phenol conversion. university of baghdad college of engineering iraqi journal of chemical and petroleum engineering effect of operation conditions on catalytic oxidation of phenol in aqueous solution 22 ijcpe vol.9 no.4 (2008) experimental work catalyst preparation cuo.al2o3 catalyst with composition of 10 wt. % of cuo was prepared by impregnation method. the carrier (γ-alumina) was calcined at 873 k with air for six hours then placed in a desicator before impregnation step. evacuation is operated to remove the air from pores of the carrier. the impregnation solution is prepared by dissolving 19 g of copper nitrate in 50 ml of deionized water. the impregnation process was carried out under vacuum accompanied with shaking for an hour at fixed temperature of 343 k. the impregnated alumina is dried at 383 k over night and calcined at 673 k for eight hours. the same procedure was followed to prepare the other. table 1,shows the chemical composition and calcined temperature of prepared catalysts. table 1 lists the composition of the prepared catalysts and their calcinations temperature. catalyst composition calcinations temperature, °c a cuo.al2o3 400 b cuo. silica gel. 400 c cuo. zno. al2o3 400 d cuo. zno. al2o3 500 experimental procedure the runs were made in a four-neck, 250 ml pyrex roundbottom flask. the necks housed a sampling tube, a contact thermometer, a sparger for oxygen introduction and a condenser connected to a gas-washing bottle open to the atmosphere. the gas washing bottle contained naoh solution of known concentration for the absorption of carbon dioxide (figure 1). the flask was heated with a heating mantle and stirred magnetically. oxygen was sparged through a coil containing 18 holes, each 0.15 cm in diameter. for a typical run, 250 ml of water and known weight of phenol and catalyst in powder form were loaded into the flask and heated to the desired temperature. the mixture was stirrer vigorously, slurrying the catalyst uniformly throughout the liquid. cooling water was started and oxygen was spared into the flask. representative samples were withdrawn periodically and the catalyst was separated from the aqueous phase by centrifugal forcing. the samples prepared were analyzed with uvspectrophotometer. a calibration curve was used to determine the unreacted phenol concentration in the reaction product in each run. kinetic analysis of the catalytic oxidation of phenol in the kinetic analysis of the reaction, the rate equations proposed by sadana and katzer (24) were tested. equations 1 and 2 represent these equations for the initial rate and the rate in the steady state activity regime, respectively.   5.01 1 1 vcm phc k dt phdc cm v  (1)  31 2 1 vcm phc k dt phdc cm v  (2) if these equations are written in terms of conversion and –ln(1-x) value are plotted versus time, the slop of the curve at x=0, t=0 gives k1 and the slope in the steady state activity regime gives k2. results and discussion determination of the most active catalyst figure 2 presents a comparison of the activities of catalysts prepared. it can be seen that the catalyst composed of cuo.zno.al2o3 (catalyst d) is the most active one. the catalyst can be ranked as follows in terms of activity in phenol oxidation: cat.d > cat.c > cat.a > cat.b the influence of the calcinations temperature on the catalyst activity is illustrated by figure 2, which compares the phenol conversion profiles for cat.c and cat.d, both with 10% of copper oxide and 2% of zinc oxide supported over γ-alumina. the catalysts were calcined at 400ºc and 500ºc receptively. both catalysts behave similarity, so one can infer that the calcinations temperature does not have the significant effect on the catalyst activity except that the induction period of cat.c is greater that cat.d because of the “free oxide” caused by the calcinations temperature. the evolution of the catalytic activity has been related to the presence of two different species of copper attached to the alumina surface. the first would be more active but also less stable in reaction condition. on the other hand, the second species would be more stable and responsible for the residual activity of the catalyst. a characterization of the catalysts (x-ray analysis) proved that these species are respectively “free” copper oxide and nonstochiometric copper aluminate. it is well-known that the most metal oxides, as copper oxide, dissolve in hot acidic media such as the one existing in the reactor. on the other hand, the treatment at high temperature, e.g. a calcinations temperature of 400°c and 500°c, of a mixture of copper and aluminum oxides forms copper aluminates that is more resistant to the acidic medium but is less catalytically active than the “free” copper oxide. wadood t. mohammed, hisham a. kadim 23 the loss in catalytic activity can be attributed to the leaching of copper from the catalyst during the process. this speculation is proved by figure 3 it should be noted that the total amount of cu+2 that dissolves during the reaction time rapidly increases until giving the maximum cu+2 concentration at (20,33,15, and 13) ppm for the catalyst a, b, c, d respectively. this behavior agrees with the presence of the two different species, the “free” copper oxide being easily dissolved during the first hours. when the ph is low, the catalysts show a fall in activity regardless the support, however after a variable period; the alumina-supported catalyst activity remains stable. in contrast, the silicasupported activity decreases sharply until the phenol conversion is negligible. these different trends are related to the presence of two active species in the alumina-supported catalyst, copper oxide and copper aluminates, whereas the silica-supported catalyst only has copper oxide. also for the phenol oxidation reaction it might be worthwhile to test the influence of promoter metal like zn. this promoter changes the vulnerability of the copper oxide poisoning. furthermore, it has been suggested that promoter also can protect the active metal against over– oxidation. many researchers concluded that the presence of promoter caused that, lower sensitivity to poisoning and enhancement of the dehydrogenation activity. effect of feed solution ph the previous results demonstrate the intrinsic relationship between the catalyst activity and the ph of the reactor solution. therefore, cat. b (cuo. silica) was prepared using silica as support in order to find out whether or not a different support for the copper oxide could improve resistance against leaching. run 1 in figure 4 shows the phenol conversion profile for cat. b feeding an unmodified phenol solution (ph=5.6). as can seen the catalyst shows very characteristic trends. cat. b has a short induction period in which the phenol conversion increases until it reaches a maximum conversion of about 41%. then it losses its activity very fast after running for just 210 min the phenol conversion being very low and progressively approaching zero. this behavior could be explained by the existence of only “free” copper oxide linked to the silica, which is easily and continuously dissolved during the activity test. in this case, copper cannot form aluminates and all the copper loading is present as copper oxide. in order to decrease the leaching of copper, various tests at higher phs were conducted for cat. b and cat.d. figure 4 also displays the phenol conversion profiles for cat. b. at a feed ph of 7.5 (run2), the induction period almost greater giving an initial phenol conversion close to 55%. then, the conversion begins to decrease, which indicates that this ph does not completely prevent the copper oxide from being dissolved. the reason for this behaviour is that, although the inlet ph is basic, the outlet ph (samples withdrawn) is still acid. on the other hand, the induction period becomes greatest for run 3 in which the feed solution was fixed at ph = 9. it should be pointed out that this case has almost constant phenol conversion through out the first time. however, there is a significant difference between the conversions reached through out 120min. at ph = 9, the phenol conversion is nearly 50% while at ph = 7.5, the phenol conversion is higher. thus, the higher the ph, the higher the remaining phenol conversion, so the inlet ph clearly affects the activity of the catalysts. this can be explained by the different rates of dissolution of the copper oxide in the aqueous solution. the solubility of any metal oxide is usually higher at low ph than at high ph. hence, in run l, the rate of dissolution for the copper oxide should be the highest. a visual inspection through out the test certainly showed an intense decolouration of the catalyst due to the loss of copper. this decolouration was less important as the ph increased, which proves that a high ph prevents the leaching of copper. nonetheless, it is difficult to discern whether or not the remaining conversion is only due to the different rate of catalyst deactivation or there is also some change in the mechanism reaction. it has been shown that phenolate ion is much more reactive than phenol in basic media so the reaction occurs faster and gives a better phenol conversion. however, each of them shows similar reaction rates in acidic media because the phenolate concentration is very low. the influence of the feed ph on the catalytic activity was also tested for cat.d figure 5 illustrates the dependence of the phenol conversion up on the ph using cat.d as can be seen, behavior of this catalyst maintains the general trends given by cat. b, regardless of the ph, so two different activity curves are observed. in the first curve, the catalysts show high activity for a short period in which the phenol conversion nearly reach higher value, then after a progressive fall, the phenol conversions remains nearly constant and forms a second curve. the loss in catalytic activity can be delayed by increasing the ph but, in turn, the residual phenol conversion is lower at high basic solution. thus, at ph of 5.6, the residual phenol conversion is slightly higher than 50% and increase to 60% at ph 9. as discussed above, the two curves can be explained because of the two different copper species over the alumina surface, both with different catalytic activity. the decrease in activity occurs when the most active copper oxide dissolves. because of their characteristics, these oxides dissolve more slowly as ph increases so the first curve is longer in basic medium. however, the remaining conversion is also lower, which is opposite to what could be expected. a probable explanation for this lower conversion is that the basic effect of operation conditions on catalytic oxidation of phenol in aqueous solution 24 ijcpe vol.9 no.4 (2008) medium interferes with the catalyst during the induction period, giving less active catalysts. effect of phenol to catalyst concentration ratio figure 6 shows the conversion of phenol versus time curves for different catalysts concentration. the highest phenol conversion was obtained with catalyst concentration of 6 g/l. the influence of the catalyst amount on the rate of phenol oxidation and the selectivity to co2 and h2o or harmless compound was studied at conditions with 2, 4, 6, 8 g/l of catalyst. it was found that the conversion of phenol increased as the amount of catalyst increased. however, the relationship between the conversion and the catalyst concentration does not appear to be linear as can see in figure 6. a low phenol conversion of 30% was obtained at steady state when 2 g/l of catalyst was used. this can be explained by an insufficient amount of catalyst used. with 6 g/l of catalyst, phenol conversion of about 60% was obtained during the first 210 min of reaction time, however, after 210 min a gradual decline in conversion was noted. similarly, using 8 g/l of catalyst, phenol conversion of 60% was obtained during the first 180 min of reaction time, however after 180 min, catalyst deactivation occurred. in addition to the formation of polymeric products, analysis of the brownish colored liquid showed increased formation of p-benzoquinone, maleic acids, and other low molecular weight acid. this unusual dependence on catalyst loading can be explained by the phenomena of a heterogeneoushomogeneous reaction mechanism which was first proposed by sadana and katzer (1974). according to this mechanism, the reaction begins on the catalyst surface, and after the homogenous propagation step, the chain carriers are destroyed by a homogeneous or heterogeneous termination process depending on the catalyst concentration. effect of air feed rate figure 7 shows the conversion of phenol versus time curves for different air feed rates. the highest phenol conversions were obtained with air feed rate of 40 ml/s. it is evident that phenol removal increases with increasing amounts of bubbled air gas. the decrease in phenol conversion observed with an air feed rate of 50 ml/s , interface and shortened residence time of large air bubbles formed by the collapsing of fine bubbles at air rates greater than a critical value. also, it can be seen that when insufficient oxygen is fed, the reaction is dominated by the formation of low ph with low selectivity to co2. at high air rate, both pbenzoquinone and maleic acid were detected in high concentration in the brownish coloured liquid. as the intensity of the brownish color in the reactor solution increased, insoluble compounds, attributed to polymeric products, are also formed in addition to the increase of the p-benzoquinone concentration. these results support the hypothesis that the extents of oxygen converge on the catalyst surface influences the selectivity of the reaction. effect of stirring speed figure 8 presents the variation of phenol conversion with time at different stirring speed in experiments of 6 hours. as the stirring speed increases from 400 rpm to 600 rpm, the conversion of phenol increases appreciably and the induction time decreases significantly. the stirring speed was 600 rpm in all the runs in this study, ensuring vigorous mixing and uniformity throughout. thus, increasing the liquid to particle mass transfer coefficient causes the absence of liquid to particle mass transfer resistance, also increasing in turbulence of mixing causes an increase in interfacial area of mass transfer. at 400 rpm, some parts of the catalyst particles remained at the bottom due to gravity causing significant decrease in phenol consumption. increasing the stirring speed to 800 rpm, increased the rate of break-up and hence decreasing the bubble size of dispersed phase, this can result in making the bubble rigid spheres. in this condition, there is no internal movement within the spheres, no new surfaces are produced and the oxidation rate is slow. effect of temperature figure 9 presents the variation of phenol conversion with time at different temperatures viz (80, 90, and 100ºc). it was found that at temperatures of 90 and 80 ºc, phenol conversion were about 53% and 32% respectively. at lower temperatures the residual phenol concentration increased gradually, while a decline in the activity of the catalyst was observed, analysis of the liquid samples obtained at 80ºc, which was characterized by a brownish colour, showed increased formation of p-benzoquinone and maleic acid. these observations indicate that a high temperature enhances the reaction and the activity of the catalyst. at high temperature the catalyst can handle higher oxygen and intermediate compound loads are employed deactivation by over–oxidation takes place. however, at high temperature the activity of the catalyst was enhanced. wadood t. mohammed, hisham a. kadim 25 kinetic analysis of the catalytic oxidation of phenol in the kinetic analysis of the reaction, the rate constants k1 and k2 were calculated from the –ln(1-x) vs. time curve. the rate constant k1 was determined from the initial rate equation at the point x=0 , t=0 by means of the differential method and k2 for the steady state activity regime was established from the slope of the -ln(1-x) vs. time line drawn using the least square techniques of the steady state activity region data. the linearity of the experimental data in the steady state activity regime displays first order kinetics with respect to phenol concentration. the rate constants k1 and k2 given in figure 10 were found to be: with phenol/catalyst ratio = 4/6 k1 = 1.9*10-3((cm3liq/gcat)0.5s-1) k2 = 2.4*10-10((cm3liq/gcat)2s-1) the difference in the result with other researchers (24) may arise from the reaction conditions and the type of conditions and the type of catalyst used. fig. 1: experimental setup 0 100 200 300 400 500 tim e (m in) 0 10 20 30 40 50 60 c o n v e rs io n % cat.a cat.b cat.c cat.d fig. 2, comparison of the activities of the catalyst reaction conditions: initial phenol concentration=4g/l, catalyst conc.=6g/l, air flowrate=30ml/s, stirring speed=600rpm, temperature=100ºc. 0 100 200 300 400 500 tim e (m in) 0 5 10 15 20 25 30 35 c u + 2 c o n c e n tr a ti o n cat.a cat.b cat.c cat.d fig. 3, copper concentration profile of the reaction mixture reaction conditions: initial phenol concentration=4g/l, catalyst conc. =6g/l, air flowrate=30ml/s, stirring speed= 600rpm, temperature=100ºc 0 100 200 300 400 500 time (min) 0 10 20 30 40 50 60 c o n v e rs io n % run 1 (ph=5.6) run 2 (ph=7.5) run 3 (ph=9) fig. 4, effect of the feed solution ph on cat.b performance reaction conditions: cat.b conc. =4 g/l, initial phenol concentration=4 g/l, air flowrate=30 ml/s, stirring speed=600 rpm, temperature=100ºc 0 100 200 300 400 500 time (min.) 0 10 20 30 40 50 60 70 c o n v e rs io n % run 1 (ph=5.6) run 2 (ph=7.5) run 3 (ph=9) fig. 5, effect of the feed solution ph on cat.d performance reaction conditions: cat.d conc.=6 g/l, initial phenol concentration=4 g/l, air flowrate=30 ml/s, stirring speed=600 rpm, temperature=100ºc effect of operation conditions on catalytic oxidation of phenol in aqueous solution 26 ijcpe vol.9 no.4 (2008) 0 100 200 300 400 500 time (min) 0 10 20 30 40 50 60 70 80 c o n v e rs io n % cat. conc.=2g/l cat. conc.=4g/l cat. conc.=6g/l cat. conc.=8g/l fig. 6 effect of catalyst concentration on phenol oxidation. reaction conditions: initial phenol concentration=4g/l, air flowrate=30 ml/s, stirring speed= 600 rpm, temperature=100ºc 0 100 200 300 400 500 time (min.) 0 10 20 30 40 50 60 70 80 c o n v e rs io n % air feed rate=30 ml/s air feed rate=40 ml/s air feed rate=50 ml/s fig. 7, effect of air feed rate on phenol oxidation. reaction conditions: phenol/catalyst concentration ratio=4/6 g/l, cat. conc. =6g/l stirring speed= 600rpm, temperature=100ºc 0 50 100 150 200 250 300 350 400 time (min.) 0 10 20 30 40 50 60 70 80 c o n v e rs io n % st irring speed=400rpm st irring speed=600rpm st irring speed=800rpm fig.8 effect of stirring speed on phenol oxidation. reation conditions: phenol/catalyst concentration ratio=4/6 g/l, catalyst conc.=6g/l, air flowrate=30ml/s, temperature=100ºc. 0 10 20 30 40 50 60 70 80 0 100 200 300 400 500 600 time (min) c o n v e rs io n % t=80°c t=90°c t=100°c fig. 9 effect of temperature on phenol conversion fig. 10 –ln(1-x) versus time curve for phenol/catalyst ratio of 4/6 conclusions 1in this study, the oxidation of phenol in aqueous solution over a supported copper oxide, zinc oxide catalyst was investigated at atmospheric pressure. the oxidation rate of phenol was low due to the solubility of oxygen in these conditions. the reaction comprised an induction period and a steady state activity regime. the initial rate and steady state activity regime exhibited first order behavior with respect to phenol concentration. the rates show an unusual dependence on catalyst loading. the initial rate and the rate in the steady state activity regime, per unit mass of catalyst, decreased as the catalyst concentration increased. these observations support the conclusion that the reaction involves a heterogeneous-homogeneous free radical mechanism that is, as the catalyst concentration increases, the chain termination on the catalyst surface becomes significant. 2the experiments showed that the length of the induction period decreased as the ratio of initial phenol concentration to catalyst concentration increased. wadood t. mohammed, hisham a. kadim 27 3when the ph is low, the catalyst shows a fall in activity regardless the support, however, after variable period, the alumina-supported catalyst activity decreases sharply until the phenol conversion is negligible. 4in alumina supported catalyst, two active spices present i.e. copper oxide and copper aluminate, whereas the silica supported catalyst only has copper oxide. 5an increase in stirring speed, as expected increased conversion of phenol appreciably and decreased the induction time significantly. nomenclature cph concentration of phenol mol/cm 3 k1 rate constant for initial rate (cm 3 of liquid/g of catalyst) 0.5 (s) -1 k2 rate constant for steady state activity (cm 3 of liquid/g of catalyst) 2 (s) -1 mc weight of catalyst g t time s v1 liquid phase volume cm 3 x conversion of phenol reference 1. lanoutte k.h. treatment of phenolic wastes. chem. eng. progress october, 99-106, 17 (1997). 2. wilhemi a.r. and knopp p.v. wet air oxidation: an alternative to incineration. chem. eng. progress, 46-52, 75 (1979). 3. singer p.c. and gurol m.d. dynamics of the ozonation of phenol. experimental observations. water res., 1163-1171, 17 (1983). 4. gurol m.d. and nekouinaini s. kinetic behavior of ozone in aqueous solutions of substituted phenols. ind. eng. chem. fundam., 54-60, 23 (1984). 5. gurol m.d. and vatistas r. oxidation of phenolic compounds by ozone and ozone+uv radiation: a comparative study. water res., 895-900, 21 (1987). 6. flynn b.l. and flemington w.v. wet air oxidation of waste streams. chem. eng. progress. 66-69, 75 (1979). 7. dietrich m.j., randlle t.l. and canney p.j., wet air oxidation of hazardous organics in waste water, environ. prog. (1985). 8. wei y.y., and wan c.c., heterogeneous photo catalytic oxidation of phenol with titanium dioxide powders, ind. eng. res., 1293-1300, 30 (1991) . 9. chattergee s., sarkar s. and bhattarchayya s.n. "photodegredation of phenol by visible light in the presence of colloidal fe2o3", j. photochemical, a chem. (1994). 10. thornton and savage, phenol oxidation pathways in supercritical water. ind. eng. chem. res., 2451-2456, 31 (1992a). 11. lim p.k., cha j.a., and patel c.p., ind. eng. chem. fundam., 387-392,23 (1984). 12. comninellis ch., electrochemical treatment of wastewater containing phenol, trans. i. chem. eng. (1992). 13. comninellis ch. and pulgrain c., electrochemical oxidation of phenol for wastewater treatment using sno2 anodes, j. appl. electrochem., (1993). 14. sadana a., katzer j.r., involment of free radicals in aqueous phase catalytic oxidation of phenol solution over copper oxide, j. catal., 140-152, 35 (1974b). 15. prudeu b., and le h., wet air oxidation of soluble components in waste. t. chem. eng., 319-325, 54 (1979). 16. ohta h., goto s., and teshima h., liquid phase oxidation of phenol; in a rotating catalytic basket reactor, ind. eng. chem. fundam. 180-185, 19 (1980). 17. devlin h., and harris i., mechanism of the oxidation of aqueous phenol with dissolved oxygen, ind. eng. fundam. 387-392, 23 (198). 18. levec j., catalytic oxidation of toxic organics in aqueous solution, appl. catal. l1-l2, 63 (1990). 19. joglekar h.s., samant s.d. and joshi j.b., kinetics of wet air oxidation of phenol and substituted phenols. water res. 135-145, 25 (1992). 20. tukac v., and hanica j., collect. czech. chem. common. 482-488, 60 (1995). 21. fortuny a., bengoa c., font j., castells f., and fabregat a., catal. today 107-153 (1999). 22. eftaxias a., font j., fortuny a., giralt j., and fabregat a., kinetics modeling of catalytic wet air effect of operation conditions on catalytic oxidation of phenol in aqueous solution 28 ijcpe vol.9 no.4 (2008) oxidation of phenol by simulated annealing, appl. catal. b: environmental, 175-190, 33 (2001). 23. zazo j.a., casas j.a., mohedano a.f., gilarranz m.a., and rodriquez j.j., chemical pathway and kinetics of phenol oxidation by fenton's reagent. environ. sci. technol. 9295-9302, 39 (2005). 24. sadana a., and katazer j.r., catalytic oxidation of phenol in aqueous solution over copper. ind. eng. chem. fundam. 127-133, 13 (2) (1974a). iraqi journal of chemical and petroleum engineering vol.18 no.2 (june 2017) 95 107 issn: 1997-4884 upgrading of al-rustamiyah sewage treatment plant through experimental and theoretical analysis of membrane fouling raheek i. ibrahim electromechanical engineering department, university of technology, baghdadiraq e-mail: doctorraheek@yahoo.com abstract al-rustamiyah plant is the oldest and biggest sewage treatment plant in iraq; it locates in the south of baghdad city. the plant suffers from serious problems associated with overflow and low capacity. the present work aims to upgrade the heart of biological treatment process through suggesting the use of membrane bioreactor; (mbr). in this work, fouling of membrane during sewage treatment has been analyzed experimentally and theoretically by fouling mechanisms. aeration has been applied in order to control fouling through producing effective diameters of air bubbles close to the membrane walls. effect of air flow rate on flux decline was investigated. hermia's models were used to investigate the fouling mechanisms. the results showed that cake formation is the best fitted model (r 2 ≥0.98) followed by intermediate blocking occurred with 9 l/min aeration rate. cake layer formation is the best fit mechanism in all aeration rates (1-9 l/min) in presence of microalgae. sem images of the membrane surface before and after filtration showed high density pores membrane surface proved a cake fouling occurring. it was found that aeration represents the most effective technique for fouling domination in addition to its important economic aspects for algae growth and propagation. an enhancement of 70.8% in flux at 9 l/min air flow has been revealed. mbr proved to be more efficient and more convenient than activated sludge since it eliminates the needing of sedimentation tanks and upgrading al-rustamiyah plant that has low available space for expansion. key words: aeration; fouling mechanisms; membrane filtration; sewage treatment; membrane bioreactor. introduction clean water is a great uttermost, especially with diminishing of water resources all over the world. a submerged membrane bioreactor is a promising technique to produce clean water from sewage wastewater, but, membrane fouling constantly holds back the membrane performance. the submerged membrane bioreactor (smbr) offered a very attractive solution to a numerous wastewater treatment issues, especially, in the field of biological treatment for industrial or sewage wastewater. the widespread range of applications comes from its integration between the biological university of baghdad college of engineering iraqi journal of chemical and petroleum engineering mailto:doctorraheek@yahoo.com upgrading of al-rustamiyah sewage treatment plant through experimental and theoretical analysis of membrane fouling 96 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net treatments of activated sludge plus membrane separation process without needing of further settling tanks which diminishes the system footprint, with enclosing of high effluent quality. rather than separation of organic pollutants that has been carried out by microfiltration (mf) or ultra filtration (uf), but the membrane fouling restricts its expanded applications. therefore, to get advantage from this widespread usage, plentiful studies have been carried on membrane bioreactor (mbr) to examine the fouling action on membrane performance [1 and 2]. the effect of biomass fouling that is due to microorganisms which are separated by mf (≥0. 1) and uf (0.01-0.1µm) membranes. previous researches focused on modeling of membrane fouling concentrated on characterization of fouling [1, 2, 3 and 4]. hermia [5] suggested four various models to describe fouling, they were: complete pore blocking, standard pore blocking, intermediate pore blocking, and cake formation. other researchers [6 and 7] have supported that, fouling has been caused by several mechanisms, the resistance in series model uses darcy's law which split the total resistance into membrane resistance and cake formation but they were not applied for bioreactors. hermia's model has been applied to aerobic mbrs [8]. the fractal permeation model developed by meng [9], produces a potential evaluation to the permeability of cake layer during activated sludge microfiltration. a comparative model considered the membrane fouling by decreasing its surface area due to foulants engagement [10]. in order to keep high performance in mbr operation, the control on fouling must be done. different techniques have been established for this purpose. the popular methods for fouling control involve: optimizing the hydrodynamic conditions in mbr, run of membrane systems below the critical flux, pretreatment of feed, membrane backwashing and cleaning [11], or involving membrane coating [12], and adsorption of suspension [13]. recently, the most common and high efficiency strategy is conducting of air scour to control the fouling extensively by mitigating the fouling through the effect of shear stress. the shear stress has a limited effect on prohibition of small particles (<1µm) to deposit on membrane surface, but this aeration process represents the important operation cost in mbr. bio-treatment of wastewater using the microalgae is predominantly charming method since it has an ability of photosynthesis transforming solar energy into advantageous biomass consolidating nutrients as nitrogen and phosphorous to eutrophication [14]. the technology and biotechnology of microalgae culture and its using in wastewater treatment have been frequently sought [15, 16, 17, 18, 19 and 20]. in wastewater such as sewage wastewater system, it has been planned to eliminate, at most dissolved nitrogen and phosphorous, is coming to be most significant stage in the treatment. the drainage of these nutrients into sensitive water bodies impresses the eutrophication by stimulating the growth unfavorable plants for example algae and aquatic macrophysics. one more impact of nitrogen compounds in wastewater are toxicity of non-ionized ammonia to fish and other aquatic organisms, conflict with disinfection where a free chlorine residual in demand and methemoglobinemia in influents as a result of interoperate nitrate concentrations (more than 45 g/m 3 ) in drinking water [21]. the http://www.iasj.net/ raheek i. ibrahim -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 97 treatment of sewage is aimed also to remove all the organic ions by means of biological or chemical methods. the biological process is more efficient and cost effective than chemical method that cause another pollutions by the chemicals used, rather than additional cost consumed for further steps of treatment. several investigations mentioned on the biological oxidation to eliminate more than 90% of bacteria from sewage using different ways of aeration, while the suspension is kept through mechanical agitation or mixing by air diffusers [22]. aeration gives advantages of mbr through offering oxygen mass transfer to algae growth, although control on fouling of membrane surface by changing the aeration rate and consequently shear stress exists in the vicinity of the membrane by fine air bubbles leading to fouling mitigation. many researchers studied the effect of aeration on membrane fouling in different conditions, but for mbr, limited studies have been found on controlling of fouling by changing the aeration conditions and hydrodynamics [23, 24, 25 and 26]. in iraq, alrustamiyah plant is the major site for sewage treatment placed in the south of baghdad city. the plant suffers from many problems associated with overload and lack in its specific design efficiency especially with overpopulation and water limitations set by neighboring countries in the recent years. according to our information, there is no existent study dealing with analysis of membrane fouling during sewage handling in smbr, although, it is a quite serious problem facing this needful treatment. thus, the main objective of this work is to upgrade al-rustamiyah sewage treatment plant through design and operate the algae submerged membrane bioreactor specialist for using to treat sewage wastewater, as well as analyzing the fouling mechanisms to award specific design and operating hydrodynamic parameters. mechanisms of membrane fouling hermia [5], concluded a mathematical model (equation 1) to characterize the permeate flux decline. this model is based upon conventional fixed pressure filtration. the fouling mechanism is sympathized involving this blocking filtration law or hermia's model. n dvdtkdvtd )/()/( 22  …(1) the exponent n in equation 1 identifies kind of filtration mechanisms. the fouling mechanisms characterizations are donated bellow. 1. complete pore blocking it takes place when the sizes of filtration solutes are bigger than membrane pores. the solutes will fully hinder or plug the membrane pores without overlap of the solutes. the filtration impedance rises when number of unclosed membrane pores reduces [27]. consequently, permeate flux decreases exponentially with time. filtration volumetric flow rate will relate with time as in equation 2: )][exp(0 ctjjt  …(2) where, ɛc= abv0 ab is the blocked surface area per unit of total permeated volume, and v0 is the initial volumetric flow rate per unit area of porous membrane surface. so, the evaluated development with time of permeates volumetric flow are presented in equation 3: ctjjt  0lnln …(3) 2. standard pore blocking it has been titled as internal pore blocking. it happens when tiny particles precipitate on the walls of http://www.iasj.net/ upgrading of al-rustamiyah sewage treatment plant through experimental and theoretical analysis of membrane fouling 98 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net membrane pore [28]. however, it occurs while the sizes of the solutes become lesser than the size of the pore entrances. precipitation of particles on the walls or inside the membrane holds-up considerably raise the resistance of filtration and lighten the rate of filtration while the volumes of membrane pore are diminished. the volumetric flow rate and time is correlated as in equation 4: 2 )1/(0 stjjt  …(4) where 2/1)0/(0 jarv ar is the decrease in pores cross section area per unit of permeate flux. a linear equation which represents volumetric flow rate with time is specified by equation 5: stjjt  2/12/1 )0/(1)/(1 …(5) 3. intermediate pore blocking here, the particles diameters are quite identical to the membrane pore size. the mechanism supposes that particles may be taken off regularly above the prior precipitated particles. several particles can immediately prevent and coat somewhat effective membrane space [27]. according to that hypothesis, any position at the surface of membrane is posed to a similar opportunity for covering by particles. thus, it has been known as intermediate pore blocking. the volumetric flow rate with time correlation is shown by equation 6: )1/(0 itjjt  …(6) where, ɛi=abv0/j0. now, the attributed growth in the permeate flux with time is offered in equation 7: itjjt  0/1/1 …(7) 4. cake formation this mechanism may be carried out while the deposited particles showing a form of surface layer. commonly this model denoted while the particles size sited in are bigger than the membrane pore size. it supposed that particles can be fixed on another pro-settled particles that coming early and then covering the surface. at this situation, the space on membrane surface is not available and the time for filtration has been extended [29]. therefore, there is a higher level of particles in this type of fouling. thus, it is well recognized as "cake formation" model. a correlation of volumetric flow rate with time is shown in equation 8: 2/1 )1/(0 cftjjt  …(8) where: 2 )0/( jccf  …(9) and 0)2( kvarrc b  …(10) by conducting equation 10 with equation 9, equation 11 will procure as: ])0/[(0)2( 2 jkvarrcf b  …(11) where 1/abk is deducted the permeate volume accumulated per unit area and rr is the ratio of the cake layer resistance to a clean membrane resistance. the relation of permeate volumetric flow with time is offered in eq. (12): cftjjt  22 )0/(1)/(1 …(12) table 1 shows the fitted equations and the values of n. http://www.iasj.net/ raheek i. ibrahim -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 99 table 1: fouling mechanisms or blocking models materials and method 1. experimental setup a submerged membrane bioreactor used in this work was designed, fabricated, tested, and run to treat a synthetic sewage wastewater. it has been consisted of 30×50×70 cm plexiglas tank with five sheets of pvdf 32×22×0.6 cm flat sheet membrane supplied by shanghai sinap membrane technology, china, the specifications of the membrane sheet was illustrated in table 2. the spacing between membrane sheets was fixed to be 0.7 cm. at the bottom of the tank there was a 3 inches diameter and 12 inches long, fine bubble air diffuser made from high grade epdm, with pore size of 2 mm, see figure 1, gives air bubble size of 1-3 mm, this air diffuser has been supplied by kamair, sanlee industry, taiwan. the tmp was fixing to be 1-4 bar be means of air gauge (weld ro model: wr 320, range 0-16 bar). the air flow rate was adjusted using air rotameter (dwyer cat. no.: rma-21-ssv, s.s. range: 1-10 l/min. air). permeate has been withdrawn from membrane sheets by 2-stage vacuum pump (type: jk-wrv-2, japan) with volumetric flow rate of 2.5 m 3 /h, and ultimate pressure of 5×10 -2 pa, and vacuum pressure gauge (mti corporation). figure 1 shows the schematic diagram of experimental setup. table 2 specifications of flat sheet membrane (sinap-10) parameter unit value pore size µm 0.1 effective membrane area m 2 0.1 size mm 220×320×6 weight kg 0.4 flux l/day 40-60 material pvdf fig. 1: schematic diagram of the membrane bioreactor set-up used 2. wastewater a synthetic sewage wastewater was prepared and used to simulate the treatment of actual sewage; its compositions for 55 liters; are as follows: peptone (0.825 gm), nahco3 (16.683 gm), kno3 (1.925 gm), nh4no3 (0.5775 gm), nah2po4.2h2o (0.0696 gm), meat extract (0.9166 gm). 3. microalgae the microalgae have been used for biological treatment of synthetic sewage wastewater. the microalgae was selected to be a strain of sperolina blocking type fouling idea particular equation n complete pore blocking pore sealing ctjjt  0lnln 2 standard blocking pore walls enclosed stjjt  2/12/1 )0/(1)/(1 3/2 intermediate blocking pore sealing and membrane surface deposition itjjt  0/1/1 1 cake formation formation of cake layers on surface cftjjt  22 )0/(1)/(1 0 http://www.iasj.net/ upgrading of al-rustamiyah sewage treatment plant through experimental and theoretical analysis of membrane fouling 100 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net platensis has been cultured in algae culture room under conditions (light intensity of 100 lux, aeration rate of 1 l/h, and a constant temperature of 21 o c) stay 10 days before using in mbr to remove nutrients from wastewater. the removal of nutrients from sewage wastewater will be considered in a future work. 4. experimental procedure after the microalgae was cultivated for 10 days. 10% concentration was used in mbr mixed with prepared synthetic sewage and entered into mbr directly. the run was beginning by opening the air valve and adjusting the air flow rate (3, 6 and 9 l/min). air bubbles were released from the diffuser as small and fine bubbles have been distributed uniformly between membrane sheets. permeate has been withdrawn from each membrane sheet using a vacuum pump and collected in a graduated cylinder to measure the permeate flux at constant tmp. the effect of air flow rate on permeate flux was noticed and recorded reflecting the presence of membrane fouling. also the increase in tmp certified membrane fouling. the run continued for a time interval 0-30 min for each air flow rate value and permeate has been recorded. results and discussion 1. aeration impact for synthetic sewage wastewater used in this study, is a type of biological solutions contain biodegradable chemicals and also algae suspension. this represents the major fouling source presents is this work where the microfiltration of pore diameter is ≥0. 1 has been used. in this work, hernias models were involved to explain fouling mechanisms which take place through microfiltration and biological treatment of synthetic sewage. the aeration influences have been clearly observed in this work through monitoring the air bubbles filling the spacing between membrane sheets; these air bubbles represent the provenience of the pivotal shear stresses. figure 2 shows the air bubbles distributed between membrane sheets spacing for the two systems used in the study at a same aeration rate (qg=6l/min). it can be seen that smaller bubbles found in algae plus wastewater system (figure 2, b) because of microalgae presence goes to air bubbles break up. fig. 2: photos of air bubbles filling the spaces between membrane sheets (a) for wastewater system, (b) for wastewater and algae suspension to investigate the effect of the air flow rate upon the membrane fouling, three levels of air flow rates (3, 6 and 9 l/min) were employed. figure 3a, shows the declines in permeates flux versus time for different aerations. it has been shown that, two phases of flux reduction have been observed, the first phase represents the flux decline through initial 25 minutes of filtration. in this phase, the decline is significantly higher in all aeration rates, however, it is further sharp at a low air flow rate (qg=3 l/min), and less sever at a higher rate (6 l/min). this phase of flux decline refers to complete pore blocking, making that http://www.iasj.net/ raheek i. ibrahim -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 101 minimal fluid that is passed through the pores of the membrane. the second phase of flux decline exists in the time range from (time=25 min and above), the decline is significantly observed in the low air flow rate (qg= 3 and 6 l/min). this second phase of decline is due to the cake layer of the solid particles accumulated on the surface of the membrane. whilst, for high aeration rate (qg=9 l/min), the reduction in flux tends to show a sacrificial one phase flux decline, this has been attributed to the cake layer formation on the membrane surface. several investigators detected comparable effects [30, 31, and 32]. furthermore, we can observe clearly, that at high aeration rate (qg=9 l/min), the amount of flux is at elevated levels than those at lower aerations (qg=3, and 6 l/min). this can be attributed to the depressed in resistance to filtration because of high shear stress values near the membrane walls resulting from high intensity of air bubbles at a high air flow rate. this high shear stress encourages the mitigation of fouling on the membrane surface leading to easier pass of liquid through the semi permeable membrane. the normalized flux decline curves for algae wastewater system (algae in the concentration of 10% added to the synthetic sewage wastewater) are shown in figure 3b. in this case, the wastewater solution becomes denser with suspended microalgae, and biomass produced from its growth. thus, it is expected that lower values of permeate flux have been obtained. we can recognize two phases of flux decline at all aeration rates. the first phase represents the initial period of filtration (until time=35 min), whereas in the first phase, a sharp decrease in flux occurred in all air flow rates, this is due to complete membrane pores blocking with large solid particles. after the first 35 minutes, the second phase enters indicated a slight reduction in flux with time because of cake formation. also, the values of flux at high aeration (qg=9 l/min), are much elevated than in lower aeration rates (qg=3, and 6 l/min), this has been attributed to the concentration polarization and high shear stresses produced by high intensity air bubbles at higher aeration. the results of kocadagistana and topcub [33] confirm our findings. fig. 3: normalized flux declines in various aeration rates for (a) synthetic wastewater, (b) algae suspension 2. fouling mechanisms analysis figure 4 (a-d), clarifies the fitting of the achieved experimental data with the wastewater system and aeration rates (3, 6 and 9 l/min) to the various attributed fouling mechanisms. from the figure, we can recognize obviously that the membrane suffers from a cake layer fouling since the mechanism is http://www.iasj.net/ upgrading of al-rustamiyah sewage treatment plant through experimental and theoretical analysis of membrane fouling 102 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net fitted well with the experimental results in the all aeration rates , while, the intermediate blocking is less fitted. fig .4: effect of various aeration rates on permeat fluxes (wastewater), according to the predicated fouling mechanisms: (a) complete pore blocking, (b) standard pore blocking, (c) intermediate pore blocking, (d) cake formation the most fitted cake formation is found at 9l/min, this can be attributed to the large particle size of the fouling compounds present in the synthetic sewage used. this particles deposit on the surface of submerged membrane forming cake layer, rather than smaller particles may enter to the pores could produce an intermediate pore blocking mostly on 9l/min aeration rate. this result shows some deviation from the fact that fouling has been reduced with increasing the air flow rate. our explanation is that at a high air flow rate, gas hold up will increase that means the amount of air inside the liquid become higher, because of elevated turbulence leads to air bubbles break up produced smaller bubbles. these small bubbles have lower shear stress than a larger one. table 3, shows the fitted r 2 values. also, table 4, explains the fit of the permeate fluxes to the predicated fouling mechanisms so as to attend with the impact of the different aeration rates on fouling. table 3: values of r 2 obtained from experimental data of membrane fouling with wastewater system mechanism qg =3 l/min qg =6 l/min qg =9 l/min complete pore blocking (n=2) 0.825 0.884 0.934 standard pore blocking (n=3/2) 0.884 0.915 0.954 intermediate pore blocking (n=1) 0.925 0.939 0.968 cake formation (n=0) 0.969 0.969 0.980 table 4: fitted hermias model parameters and effect of aeration upon membrane fouling using wastewater qg (l/min) ɛc (s -1 ) ɛs (s -1/2 m -1/2 ) ɛi (m -1 ) ɛcf (sm -2 ) 3 0.087 0.006 0.001 8×10 -5 6 0.055 0.003 1×10 -5 3×10 -5 9 0.044 0.002 1×10 -5 2×10 -5 http://www.iasj.net/ raheek i. ibrahim -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 103 it can be shown from the deviations of the experimental results and the predicated models that the cake formation is the more significant mechanism appeared in the wastewater treatment since it produced a greatest r 2 values (0.969, 0.696, and 0.980) for all aeration rates applied. while, the other mechanisms are also somewhere applied, but with less correlate. figure 5 (a-d), displays the fouling mechanisms achieved with algae wastewater (algae added to the wastewater solution). it can be distinguished that, cake formation mechanism only applied to all aeration rates, although it is more significant in low aeration (3 l/min). this can be attributed to the low turbulence level leading to solid matters deposition on the membrane surface forming a cake layer. whilst, for higher aerations (qg=6, and 9 l/min), the fouling mechanisms have been revealed, the cake formation presents in low correlation fitting. the reason can be assigned to high turbulence encourage the solid particles to move away from the surface of the membrane, rather than the effective influence of air bubbles shear stress on the membrane surface assist in fouling mitigation. thus, the cake formation mechanism has been applied to all aeration rates fouling results. also the high particle size of the algae wastewater solution hinders it to enter through the small pore size of the mf (=0.1 µm). these results are supported by gao [30]. tables 5 and 6 show the fitted r 2 values and explains the fitting of permeate fluxes to the predicated fouling mechanisms so as to attend with the impact of different aeration rates on membrane fouling. it confirms the existence of the high values of r 2 (0.973, 0.964, and 0.958) for cake formation mechanism in all aeration rates with more severe fouling at low aeration. fig. 5: effect of various aeration rates on permeate fluxes ( for algae wastewater system), according to the predicated fouling mechanisms: (a) complete pore blocking, (b) standard pore blocking, (c) intermediate pore blocking, (d) cake formation http://www.iasj.net/ upgrading of al-rustamiyah sewage treatment plant through experimental and theoretical analysis of membrane fouling 104 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net table 5: values of r 2 obtained from experimental data of membrane fouling with algae and wastewater mechanism qg =3 l/min qg =6 l/min qg =9 l/min complete pore blocking (n=2) 0.723 0.804 0.816 standard pore blocking (n=3/2) 0.821 0.864 0.866 intermediate pore blocking (n=1) 0.895 0.910 0.905 cake formation (n=0) 0.973 0.964 0.958 table 6: fitted hermias model parameters and effect of aeration on membrane fouling with algae wastewater qg (l/min) ɛc (s -1 ) ɛs (s -1/2 m -1/2 ) ɛi (m -1 ) ɛcf (sm -2 ) 3 0.086 0.008 0.003 1×10 -5 6 0.066 0.005 0.001 8×10 -5 9 0.052 0.003 0.001 4×10 -5 3. scanning electron microscopy (sem) results to achieve surface images of the membrane sheet before and after filtration, a scanning electron microscope (model vega3 tescan, usa) was utilized. figure 6a represents the image before application, it shows that the membrane had a high pore density; however, the pores were randomly distributed. figure 6b represents the image of membrane surface after application, from this image we can see that cake formation form of fouling was clearly observed. fig. 6: sem images of membrane surface (a) before filtration, and (b) after filtration 4. performance enhancement the performance of smbr used in biological treatment of sewage wastewater is represented by permeate flux improvement. from the analysis of fouling mechanisms mentioned in this study, we can prove a most common cake layer formation on the membrane surface. this deposition of algae particles results in a severe reduction in filtration process efficiency represented by depressed permeates fluxes. to overcome this problem, aeration has been used successfully in this study it appears as a perfect solution to this issue awarded a marked enhancement in flux during the biological treatment of sewage with microalgae. the use of the aeration http://www.iasj.net/ raheek i. ibrahim -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 105 method to control fouling is considered as a most power consumption stage, but in this study, it offers two advantages: the first is the microalgae growth demand, while the second profit is the control of severe cake layer formation because of microalgae existence. the values of permeate flux enhancement have been determined using equation 13. the permeate flux increases clearly to increase aeration flow rates leading to enhancement in the filtration process efficiency by up to 72.80% at 9 l/min air flow rate. awa jjjtenhancemen /%  …(13) where: ja, and jw are permeate flux with aeration and without aeration respectively. conclusions from the results, we can conclude:  mbr is the most efficient technique for al-rustamiyah plant upgrading.  the curves of permeate flux decline of the experimental data were matched to the hermia's models.  the best fittings were obtained in filtration of synthetic sewage. it can be recognized that, the cake layer formation is the best fitted mechanism followed by intermediate pore blocking.  when the microalgae presents, there are much suspended solids, in this case the best fit was the cake formation mechanism.  aeration demonstrates an effective tool to dominate the fouling as well as algae growth requirements in mbr.  experimental results proved an enhancement in the permeat flux by 72.8% using 9 l/min of aeration. acknowledgment the author of this work wish to gratefully acknowledge the financial support of chemical and process engineering department at the national university of malaysia, and prof. dr. abdul wahab mohammad / dean of faculty of engineering at ukm for his scientific supervision during my sabbatical leave. nomenclature ja aerated permeate flux (m 3 /m 2 h) jt volumetric flow rate (m 3 /m 2 h) jw permeate flux without aeration (m 3 /m 2 h) j0 initial volumetric flow rate (m 3 /m 2 h) rc cake layer resistance (m -1 ) rf fresh membrane resistance (m -1 ) rr rr=rc/rf, ratio of cake resistance to the resistance of fresh membrane (-) r 2 coefficient of determination t time (s) v0 initial mean velocity of the filtrate (m/s) greek letters ɛc complete pore blocking model constant (s -1 ) ɛs standard pore blocking model constant (s -1/2 m -1/2 ) ɛi intermediate pore blocking model constant (m -1 ) ɛcf cake formation model constant (s m -2 ) abbreviations pvdf polyvinylidene difluoride smbr submerged membrane bioreactor references 1amine, c., amar, n.b., harmand, j. "analysis of fouling mechanisms in anaerobic membrane bioreactors". water research 46, 2637-2650. (2012). 2le, j., ong, s.l., ng, h.y. "fouling control mechanism by suspended biofilm carriers addition in submerged ceramic membrane http://www.iasj.net/ upgrading of al-rustamiyah sewage treatment plant through experimental and theoretical analysis of membrane fouling 106 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net bioreactors". journal of membrane science 427, 250-258. (2013). 3huchang, h., zhang, m., he, y., cheu, j., lin, h. "fouling mechanisms of gel layer in a submerged membrane bioreactor". bioresource technology. 166, 295302. (2014). 4ching, y.n., mohammad, a.w., ng, l.y., jahim, j.m., membrane fouling mechanisms during ultrafiltration of skimmed coconut milk, journal of food engineering (article in press). (2014). 5hermia, j. "constant pressure blocking filtration laws-application to powerlaw non-newtonian fluids". icheme 60, 183–187. (1982). 6katsoufidou, k., yiantsios, s.g., karabelas, a.j. "a study of ultrafiltration membrane fouling by humic acids and, flux recovery by backwashing: experiments and modeling". journal of membrane science 266, 40-50. (2005). 7song, l. "flux decline in cross flow micro filtration and ultrafiltration: mechanisms and modeling of membrane fouling". journal of membrane science 139, 183-200. (1998). 8drews, a., arellano-garcia, h., schӧneberger, j., schaller, j., wozny, g., kraume, m. "modelbased recognition of fouling mechanisms in membrane bioreactors". desalination 236, 224233. (2009). 9meng, f., zhang, h., li, y., zhang, x., yang, f. "application of fractal permeation model to investigate membrane fouling in membrane bioreactor". journal of membrane science 262, 107-116. (2005). 10saroj, d.p., guglielmi, g., chiarani, d., andreottola, g. "subcritical fouling behaviour modelling of membrane bioreactors for municipal wastewater treatment: the prediction of the time to reach critical operating condition". desalination 231, 175-181. (2008). 11tchobanoglous, g., burton, f. l., and stensel, h. d. "wastewater engineering: treatment and reuse". mcgraw-hill, usa. (2003). 12song, k.g., kim, y., and ahn, k.h., "effect of coagulant addition on membrane fouling and nutrient removal in submerged membrane bioreactor". desalination 22(1-3), 467-474. (2008). 13guo, w. s., vigneswaran, s., ngo, h. h., xing, w. and goteti, p. "comparison of the performance of submerged membrane bioreactor (smbr) and submerged membrane adsorption bioreactor (smabr)". bioresource technology 99(5), 10121017. (2008). 14de la nou¨ e, j., de pauw, n., "the potential of microalgal biotechnology. a review of production and uses of microalgae". biotechnol. adv. 6, 725–770. (1988). 15burlew, j.s. "algal culture from laboratory to pilot carnegie institution of washington publication 600", washington. (1983). 16barclay, w.r., mc-intosh, r.p. "algal biomass technologies". beih. nova hedwigia, 83.( 1986). 17richmond, a., "handbook of microalgal mass culture". crc press, boca raton, florida, 528. (1986). 18lembi, c.a., waaland, j.r. "algae and human affairs". cambridge univ. press, cambridge. (1988). 19stadler, t., mollion, j., verdus, m.c., karamanos, y., morvan, h.,christiaen, d. "algal biotechnology". elsevier applied science, england. (1988). http://www.iasj.net/ raheek i. ibrahim -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 107 20cresswell, r.c., rees, t.a.v., shah, n. "algal and cyanobacterial biotechnology". longman scientific and technical, new york. (1989). 21lincolin, e.p., earle, j.f.k. "wastewater treatment with microalgae". in: akatsuka, i. (ed.), introduction to applied phycology. spb academic publishing by the hague, the netherlands. 429–446. (1990). 22horan, n.j., biological wastewater treatment systems. theory and operation. john wiley and sons ltd. baffins lane, chickester. west sussex po 191 ud, england. (1990). 23etienne, b., alliet, m., schetrite,s., albasi, c. "aeration and hydrodynamics in submerged membrane bioreactors", journal of membrane science 379, 1-18. (2011). 24nywening , j.p., zhou, h. "influence of filtration conditions on membrane fouling and scouring aeration effectiveness in submerged membrane bioreactors to treat municipal wastewater", water research 43, 3548–3558. (2009). 25bérubé, p.r., lin, h., watai, y. "fouling in air sparged submerged hollow fiber membranes at suband supercritical flux conditions", journal of membrane science 307, 169-180. (2008). 26ndinisa, n.v., fane, a.g, wiley, d.e, "fouling control in a submerged flat sheet membrane system. part ii. two phase flow characterization and cfd simulations", separation science technology 41, 1383–1409. (2006). 27hwang, k.-j., lin, t.-t. "effect of morphology of polymeric membrane on the performance of cross-flow microfiltration". journal of membrane science 199 (1–2), 41–52. (2002). 28bowen, w.r., calvo, j.i., hernández, a. "steps of membrane blocking in flux decline during protein microfiltration", journal of membrane science 101 (1–2), 153– 165. (1995). 29palacio, l., ho, c.-c., zydney, a.l. "application of a poreblockage—cakefiltration model to protein fouling during microfiltration", biotechnology and bioengineering 3, 260–270. (2002). 30gao, d.w., zhang, t., tang, c.y., wu, w.m., wong, c.y., lee, y.h., yeh, d.h., criddle, c.s. "membrane fouling in an anaerobic membrane bioreactor: differences in relative abundance of bacterial species in the membrane foulant layer and in suspension". journal of membrane science 364, 331-338. (2010). 31lin, h.j., xie, k., mahendran, b., bagley, d.m., leung, k.t., liss, s.n., liao, b.q. "sludge properties and their effects on membrane fouling in submerged anaerobic membrane bioreactors (anmbrs)". water research 43, 3827-3837. (2009). 32he, y., xu, p., li, c., zhang, b. "high-concentration food wastewater treatment by an anaerobic membrane bioreactor". water research 39, 4110-4118. (2005). 33kocadagistana, e., topcub, n. "treatment investigation of the erzurum city municipal wastewaters with anaerobic membrane bioreactors". desalination 216, 367-376. (2007). http://www.iasj.net/ ijcpe vol.10 no.3 (september 2009) iraqi journal of chemical and petroleum engineering vol.10 no.3 (september 2009) 25-30 issn: 1997-4884 extraction of medicinal compounds from botanicals using bulk liquid membrane in rotating film contactor: recovery of vinblastine from catharanthus roseus. adil a. al-hemiri *, sawsan a. m. mohammed*, raheeq b. alsaadi * chemical engineering department college of engineering university of baghdad – iraq abstract the interest of application of liquid membrane (pertraction) processes for recovery of medicinal compounds from dilute ammoniacal leach solutions is demonstrated. selectivity of the liquid membrane ensures a preferential transport of the desired solute from the native extract into the strip solution, vinblastine was successfully extracted fro m basic media (ph 9.2) and stripped by acidic media of sulfuric acid (ph= 1.3) applying continuous pertraction in a rotating discs contactor and using n-decane as liquid membrane. transport of vinblastine in three-liquid-phase system was studied and performed by means of a kinetic model involving two consecutive irreversible first-order reactions. the kinetic parameters (apparent rate constants of the vinblastine extraction and re-extraction reactions (k1, k2), the maximum fraction of the vinblastine in the liquid membrane (xs.max) and the time when this maximum is reached (tmax)) were calculated. solute transfer into the lm is mainly diffusion-controlled. keywords: liquid membrane, pertraction, extraction, vinblastine, catharanthus roseus introduction the established idea of a membrane is a thin, semipermeable and solid barrier. a liquid membrane (lm) is nothing like this. it is a liquid phase, usually organic, interposed between two miscible aqueous solutions. at one side of the membrane (feed solution) the material to be transported is extracted, while at the other side (stripping solution) re-extraction occurs. since in each of the aqueous solutions some specific, and different for each of them, thermodynamic conditions exist, the extraction and re-extraction occur simultaneously. such process is called pertraction i.e., extraction in one side and stripping of the extract at the other side simultaneously. the liquid membrane extraction was introduced as an alternative separation technique to the liquid-liquid extraction and to the separation by means of solid polymeric membranes [1]. this property of membranes makes them useful in the textile and food industries, in hydrometallurgy, medicine, biotechno-logy environmental protection, in the separation of hydrocarbons and gases, and in the concentration and separation of amino acids, metal ions and other mixtures and suspensions [2]. vinca or periwinkle (catharanthus roseus (linn.) g.don.) is an erect handsome herbaceous perennial plant which is a chief source of patented cancer and hypotensive drugs. it is one of the very few medicinal plants which has a long history of uses as diuretic, antidysenteric, haemorrhagic and antiseptic. the dimeric indole alkaloids from catharanthus roseus l, vinblastine (fig. 1) present in the leaves, it is mainly useful for treating hodgkin's disease, lymphocytic lymphoma, histiocytic lymphoma, advanced testicular cancer, advanced breast cancer, kaposi's sarcoma, and letterersiwe disease. these drugs because of extremely low yields are among the most expensive in the pharmaceutical market. attempts to improve their yields through cell and tissue culture have so far met with limited success. growth and differential stage-dependent university of baghdad college of engineering iraqi journal of chemical and petroleum engineering extraction of medicinal compounds from botanicals using bulk liquid membrane in rotating film contactor: recovery of vinblastine from catharanthus roseus. 26 ijcpe vol.10 no.3 (september 2009) biosynthesis of these alkaloids are still poorly understood [3]. a new bulk liquid membrane (blm) process for recovery of medicinal compounds from dilute ammoniacal leach solutions has been studied in this work. vinblastine alkaloids was extracted by means of a rotating film pertractor using various organic liquid membranes as carrier, a simple kinetic model of the mass transfer of solute in blm is advanced by considering two consecutive reactions (extraction–re-extraction of the solute) with three diffusion steps in the feed, organic and stripping solutions. fig.1 chemical structure of vbl and vbl sulphate. experimental work materials (solvents and aqueous solutions) organic solvents used in this work as liquid membrane, n-decane and n-nonane; bdh, n-heptane; riedel_dehaën and methylcyclohexane; hopkin & williams. ammonia and sulfuric acid were used as donor and accepter solution respectively. the acidity of the aqueous solutions was measured using a ph-meter (oakton ph 2100 series manufactured by eutech instruments singapore). procedure of pertraction among the large variety of liquid membrane techniques [1, 4-12] the pertraction in rotating film contactor (rfc) was selected because of its stability. kinetics of vinblastine transport in three-liquid-phase system was studied in laboratory rfc, presented schematically in fig. 2. the lower part of the contactor is divided into two compartments: one for the feed and the other for the stripping solution. the liquid organic membrane covers both aqueous solutions and occupies the common upper part of the contactor. the hydrophilic disc (1mm thick, 18cm in diameter) rotates in each compartment. the distance between fig.2, diagram showing the rf contactor used. 1: apparatus body; 2: rotating discs; 3: separating half-walls; 4, 4': feed inlet and outlet; 5, 5': strip solution inlet and outlet; 6: rotating shaft. two discs are 15mm. the discs rotation provides a formation and continuous renewal of aqueous films of solutions f and r on discs surfaces as well as the agitation of all three phases. to homogenize the aqueous solutions and to eliminate the dead zones or become little both liquids were re-circulated by means of two peristaltic pumps. the velocity of discs rotation was fixed at 10 rpm. experimental procedure 5.0 grams of fresh leaves were cut into small pieces and extracted using buffer solution of (nh3-(nh4)2so4) at ph 9.2. the volumetric flask was shaking for half hour using a shaker, filtered and poured into the rfc using glass funnel. the acceptor solution was adjusted to ph 1.3 of sulfuric acid and placed into the second compartment, the reminder volume filled with the liquid membrane. procedure of equilibrium studies the study of vinblastine transport across a liquid membrane, and its equilibrium distribution between organic and aqueous phases was established using laboratory rotating film contactor. 10 mg of vinblastine dissolved in 250 ml of buffer solution of (nh3(nh4)2so4) and adjusted to appropriate ph and placed in the first compartment. a volume of 250 ml of sulfuric acid solution (ph= 1.3) placed into the second compartment. 500 ml of nnonane covers both aqueous solutions. samples were taken from each feed, stripper and the organic layer at a certain intervals. analysis of vinblastine vinblastine samples from aqueous solutions and organic solvent during the experimental period were analyzed by ultra-violet /visible spectrometer (shimadzu 160) (λ= 276). adel a.al-hemiri, sawsan a. m. mohammed and raheeq b. alsaadi ijcpe vol.10 no.3 (september 2009) 27 results and discussion 1.choice of solvents: extraction of vinblastine by organic solvents to apply liquid membrane process for vinblastine recovery from aqueous media it is necessary to find conditions suitable for its extraction by an organic liquid, but also conditions favorable for its back extraction into the aqueous solution. preliminary test were carried out to find the optimum ph of feed (donor) solution (best diffusion to the liquid membrane), and best ph of stripping solution. the results of the extractability experiment shown in fig. 3. as shown there at law ph vinblastine protonated (sulphate salt), while for ph above 9 the results show decrease in the extractability of vinblastine. this decrease might be due to that ammonia starts to be extracted above ph 9 [13]. the loss of ammonia to the organic layer will decrease the basicity of feed solution. it is to be concluded that the best ph for the feed solution (good fig. 3, diffusion of vbl through the liquid membrane (n-decane) extraction around 9, and the best accepter (stripper) would be around ph of 1.3. such results are in agreement with that obtained by k.dimitrov et al [14] and s. k. volkov et al [15]. 2. solvent extraction of vinblastine by n-decane and other organic solvents many organic non-polar solvent are used as liquid membrane (viz. n-decane, n-nonane, n-heptane, methylcyclohexane). low molecular weight of the organic solvent failed to give reasonable extraction efficiency while n-decane (the highest molecular weight 142.29) gave a good extracting ability as shown in fig. 4. the lowest extracting ability is that of methylcyclohexane (cyclo derivative hydrocarbons) [16]. the studied alkanes are suitable for liquid membrane permeation of vinblastine, providing conditions favorable for vinblastine extraction into the organic solvent this results are agreement with the results which obtained by krasimir d. et al [8] fig. 4, effect of type of membrane on the concentration of vbl sulphate (pha= 1.3, phb =9.2). fig. 5, pertraction study of the discs speed using nnonane as lm, pha =1.3 and phb =9.2 3. various studies in pertraction a) discs rotation speed pertraction efficiency grows with the increase of discs rotation velocity as shown in fig. 5, due to the better agitation of all three phases and the faster renewal of the aqueous films .the variation of pertraction efficiency with the agitation indicates a diffusion control of the process. these results agree with the results obtained by k. dimitrov et al [14] and k. dimitrov et al [15]. extraction of medicinal compounds from botanicals using bulk liquid membrane in rotating film contactor: recovery of vinblastine from catharanthus roseus. 28 ijcpe vol.10 no.3 (september 2009) fig. 6, pertraction study of the discs material using nnonane as lm, pha =1.3 and phb =9.2 b) discs material in order to choose the proper hydrophilic disc material, two types of disc material was prepare; glass and stainless steel. the results of the pertraction of vinblastine using these two types are shown diagrammatically in fig. 6. stainless steel gives better to manipulate than glass which easily damaged [16]. 4. pertraction of vinblastine a simple kinetic model of the mass transfer of solute in blm can be advanced by considering two consecutive reactions (extraction–re-extraction of the vinblastine) with three diffusion steps in the feed, organic and stripping solutions. a comparative study of vinblastine was performed by applying this model. to do this, the following kinetic parameters were evaluated: the apparent rate constants of the solute extraction and re-extraction reactions (k1, k2), the maximum reduced concentration of vinblastine in the liquid membrane (xsmax), the time of the maximum value of xs (tmax). these results suggest that the solute transport conforms to two consecutive irreversible first-order reactions according to the kinetic scheme: s r 1 where, f: solute concentration in feed solution. s: solute concentration in extracting solution. r: solute concentration in stripping solution. k1 & k2 the extraction and stripping transfer rate coefficient respectively. for practical reasons, dimensionless reduced concentrations of vinblastine in feed solution xf, liquid membrane xs, and the stripping solution xr were used: xf = ; xs = ; xr = the kinetic scheme for consecutive irreversible reactions (eq. 1) can be described by the following rate equations: = -k1xf (2) = k1xf – k2xs (3) = k2xs (4) integrating eqs. 2–4 is easily carried out and r-values are obtained when k1≠k2, giving: xf = (5) xs = ( ) (6) xr = (k1 –k2 ) + 1 (7) at the maximum value of xs, when dxs/dt=0, this reduced concentration and tmax can be calculated as follows: tmax = = (8) xs max = (9) from figure 7, tmax= 109 min, xs.max= 0.52. by substituting these results into eqns. (8 and 9) and using matlab program gives: k2= 0.006 min-1 k1 = 0.01331 min-1 figure 7 shows the evolution of vinblastine repartition between the three liquid phases during a continuous pertraction process at constant acidity of the feed solution phb 9.2. the interaction between solute molecules of the feed solution and n-nonane occurred at the first interface f/s where vinblastine was partially extracted to organic adel a.al-hemiri, sawsan a. m. mohammed and raheeq b. alsaadi ijcpe vol.10 no.3 (september 2009) 29 phase. the process beginning is characterized by a sharp decrease of vinblastine amount in the feed solution and its instantaneous accumulation in the organic liquid membrane. due to the concentration gradient created vinblastine molecules extracted in the organic membrane phase were transferred to the second interface s/r, where the ph of the receiving solution (pha) was 1.3, therefore, vinblastine transferred and accumulated into this solution. fig. 7, time dependencies of xf, xr and xs in the transport of vbl sulphate (liquid membrane: n-nonane.) at the end of experimental run, almost of vinblastine was accumulated in the receiving solution. conclusions when the behavior of vinblastine extraction from aqueous media by various organic solvents at equilibrium was studied, the non-polar n-decane was found to be the most suitable for vinblastine recovery by pertraction process. best diffusion to the organic layer of feed (donor) solution was achieved by using buffer solution of (nh3-(nh4)2so4) at ph 9.2, and the best stripper (accepter) solution by using h2so4 with ph 1.3. increasing the leaves weight lead to increasing of amount of vinblastine in feed solution, at the same time in the membrane as well as in the stripping phase. increasing discs rotation velocity, to a certain degree, gives a better agitation of all three phases and the faster renewal of the aqueous films. the hydrophilic discs constructed of stainless steel gave a good material for manufacturing the discs with advantages of being very hygienic and easy to clean. the rate of diffusion constants was performed by means of a kinetic model involving two consecutive irreversible first-order reactions. k1 and k2 were found to be 0.01331 and 0.006 min-1. nomenclature description concentration. interface between the donor solution and organic membrane. rate constant of solute extraction. rate constant of solute reextraction. ph of accepter solution. ph of donor solution. rotating film contactor. revolution per minute. interface between the organic membrane and stripping solution. time of maximum concentration of solute in organic layer. vinblastine. dimensionless of maximum conc. of solute at organic membrane feed interface. notation conc. f/s k1 k2 pha phb rfc rpm s/r tmax vbl xsmax references 1. kralj d. and brečević l. (1998), precipitation of some slightly soluble salts using emulsion liquid membranes; croatica chemica acta ccacaa 71 (4) 1049. 2. kamiński w., kwapiński w. (2000), applicability of liquid membranes in environmental protection; polish journal of environmental studies vol. 9, no. 1, 37. 3. joy p. p., thomas j. mathew s., skaria b. p.,(1998), medicinal plants, kerala agricultural university, aromatic and medicinal plants research station. 4. danesi, p.r. and cianeti, c. (1984). multistage separation of metal ions with a series of composition supported liquid membranes journal of membrane science, 20 (2): 215. 5. izatt r. m., jones m. b., lamb j. d., bradshaw j. s. and christensen j. j. (1986), macrocyclemediated cation transport from binary hg2+ m2+ mixtures in a 1m hno3-chcl3(1m) hno3 liquid membrane science, journal of membrane science, (26) 241-250. 6. bacon e. and jung, l. (1985). selective extraction and transport of mercury through a liquid membrane by macrocyclic ligands. improvement in the transport efficiency and an approach to physiological systems journal of membrane science, 24: 185. extraction of medicinal compounds from botanicals using bulk liquid membrane in rotating film contactor: recovery of vinblastine from catharanthus roseus. 30 ijcpe vol.10 no.3 (september 2009) 7. brown p.r., izatt, r.m., christensen, j.j. and lamb, j.d. (1983). transport of eu2+ in a h2ochcl3-h2o liquid membrane system containing the macrocyclic polyether 18crown-6, journal of membrane science, 13: 85. 8. dimitrov k., gancel f., montastruc l., nikov i. (2008), liquid membrane extraction of bioactive amphiphilic substances: recovery of surfactin; biochemical engineering journal (42) 248, elsevier. 9. boyadzhiev l., alexandrova s. (1994), recovery of copper from ammoniacal solutions by rotating film pertraction; hydrornetallurgy, (35) 109 10. a_kiba, k. and hashimoto, h. (1985), extraction of uranium by a supported liquid membrane containing mobile carrier, talanta, 32, 8b: 824. 11. chiarizia, r. and castagnola, a. (1983). mass transfer rate through solid supported liquid membranes influence of carrier dimerization and feed metal concentration on membrane permeability, journal of membrane science, 14:1. 12. martin, t.p. and davies, g.a. (1977). the extraction of copper from dilute aqueous solutions using a liquid membrane process, hydrometallurgy, 2 (4): 315. 13. noble r.d. and stern s.a. (1995), membrane separations technology, principles and applications, chapter 7; elsevier science. 14. k. dimtrov, d.metcheva, s.alexandrova, l.boyadzhiev (2006) selective recovery of atropane applying liquid membrane technique; chem. biochem. eng. 55-59. 15. volkov, s. k. and grodnitskaya e. i. (1995), chemical stability of vinblastine; pharmaceutical chemistry journal, vol. 29, no. 8. 16. alsaadi r.b. (2009), extraction of medicinal compounds from botanicals using bulk liquid membrane in rotating film contactor, thesis chemical engineering department, of the college of engineering, university of baghdad. available online at https://ijcpe.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.19 no.1 (march 2018) 61 – 66 issn: 1997-4884 corresponding authors: zaid adnan abdel-rahman, email: zaid572010@yahoo.com iraqi journal of chemical and petroleum engineering a comparison between the product-refill and the equalization oxygen pressure swing adsorption processes zaid adnan abdel-rahman chemical engineering department, college of engineering, tikrit university, iraq abstract this work presents a design for a pressure swing adsorption process (psa) to separate oxygen from air with approximately 95% purity, suitable for different numbers of columns and arrangements. the product refill psa process was found to perform 33% better (weight of zeolite required or productivity) than the pressure equalization process. the design is based on the adsorption equilibrium of a binary mixture of o2 and n2 for two of the most commonly used adsorbents, 5a & 13x, and extension from a single column approach. zeolite 13x was found to perform 6% better than zeolite 5a. the most effective variables were determined to be the adsorption step time and the operational pressure. increasing the adsorption step time from 1 to 5 minutes decreased the performance by approximately 5 times. increasing the pressure from 2 to 6 bars increased the performance by approximately 3 times. keywords: oxygen production, psa, process design, product refill, equalization 1introduction the pressure swing adsorption (psa) process for oxygen separation from air is an important alternative unit operation in the chemical industry. it has advantages in energy consumption and cost over other methods, but is only used in approximately 20% of oxygen production especially on the small-to-moderate scale. however, the cryogenic process is currently used in approximately 80% of all oxygen production on the moderate-to-large scale. the analysis of previous works over the last three decades regarding the psa process for oxygen separation from air using one-, two-, three-, and four-columns with different steps and arrangements allowed for the design of a process that produces high-purity oxygen with reasonable recovery and productivity. two main arrangements of the psa process were found: the product refill process and the pressure equalization process. the commercial zeolites 5a and 13x were the primary adsorbents used in these works. the end product is limited to 95% oxygen because of the presence of argon in air and because the zeolite adsorbents present have similar adsorption capacities for oxygen and argon [1-23]. the design of the psa process was based on two principles. the first is the equilibrium between solutes in the fluid phase and the solute-enriched phase of the solid adsorbent. the understanding of the adsorbent material equilibrium properties, especially capacity as a function of pressure, is of primary importance. the second is that the fixed-bed process operates as a periodic or cyclic steady state, with several different steps constituting a cycle. thus, knowledge of the transitional behavior of a single bed is necessary for the system design. both time and space were used in the analysis, which is in contrast to many chemical engineering operations that can be analyzed at the steady state that only have a spatial dependence. for an optimal design, it is crucial to understand fixedbed performance in relation to the adsorption equilibrium and rate behavior. an empirical approach is frequently used to design the psa process, using the adsorption equilibrium capacity of the adsorbents, breakthrough time of a single column, and mass transfer zone (mtz) approach [24-27]. the psa process performance is represented by the oxygen purity of the product, recovery (oxygen in product to oxygen in feed) and productivity (continuous oxygen product flowrate to zeolite weight). the performance is affected by the following variables: pressure, cycle time or adsorption step time, purge flow ratio, feed flowrate, and product flowrate. no comparison study between the two psa process arrangements, the product refill and the equalization process has been performed. the objectives of this study are to develop a simple empirical design model of the psa process for the separation of oxygen from air that is suitable for different numbers of columns, to compare the two psa process arrangements (product refill process and pressure equalization process), and to study the effect of system variables on the zeolite weight required and/or the process productivity for a specified function. z. a. abdel-rahman / iraqi journal of chemical and petroleum engineering91,9 (2018) 29-43 26 2process design approach in this work, the adsorption equilibrium, the single column breakthrough approach, stoichiometry and the experience of the different process steps times were used as a basis for the design of the psa process for oxygen separation from air. 2.1. equilibrium isotherm the nitrogen adsorption equilibrium capacity for the adsorbents can be approximated by the following linear henry like equation as follows: (1) the value of kz equals 0.17 and 0.18 mole n2/kg zeolite.bar for 5a and 13x zeolites, respectively. the values were obtained by the analysis of the literature data [10-11, 23]. 2.2. breakthrough of single column the single column breakthrough approach was used as a basis for the design using a factor, kb, representing the fraction of bed that was used, as shown in fig. 1. fig. 1. single column breakthrough breakthrough time was used as a guide for cycle time selection, which is approximately given by the following simple mass balance equations; ⁄ (2) ⁄ (3) 2.3. psa system fig. 2 shows the five psa process cases used in present study. fig. 2: the five psa process cases used in present study z. a. abdel-rahman / iraqi journal of chemical and petroleum engineering91,9 (2018) 29-43 26 the five psa process cases of the two main process arrangements were considered in this work as follows; a. product refill or pressurizing arrangement psa processes, 4-steps (ad-dp-pg-pp) system, were used for one-column with a product flow utilized time fraction kc=1/3, two-columns with kc=2/3 and three-columns with kc=1, as shown in table 1. table 1. product refill process steps columns steps kc one-columns onecolumn ad ad dp pg pg pp 1/3 two-columns 1 st column ad ad dp pg pg pp 2/3 2 nd column dp pg pg pp ad ad three-columns 1 st column ad ad dp pg pg pp 1 2 nd column pg pp ad ad dp pg 3 rd column dp pg pg pp ad ad b. equalization arrangement psa processes, 6-steps (ad-ed-dp-pg-ep-fp) system, were used for twocolumns with a product flow utilized time fraction kc=1/2 and four-columns with kc=1, as shown in table 2. table 2. pressure equalization process steps columns steps kc two-columns 1 st column a d a d e d d p p g p g e p f p 1/2 2 nd column p g p g e p f p a d a d e d d p four-columns 1 st column a d a d e d d p p g p g e p f p 1 2 nd column e p f p a d a d e d d p p g p g 3 rd column p g p g e p f p a d a d e d d p 4 th column e d d p p g p g e p f p a d a d the total cycle time is the summation of the process steps times; ∑ (4) the 4-steps for the product refill psa process cycle (τ=3τad) is as follows: 1the adsorption (ad) step was taken time τad =1-5 minutes. 2the depressurizing (dp) step was taken time τdp=0.5* τad. 3the purging (pg) step was taken time τpg= τad. 4the product pressurizing (pp) step was taken time τpp=0.5* τad. the 6steps psa equalization process cycle (τ=4τad) is as follows: 1the adsorption (ad) step was taken time τad =1-5 minutes. 2the equalization depressurizing (ed) step was taken time τed=0.5* τad. 3the depressurizing (dp) step was taken time τdp=0.5* τad. 4the purging (pg) step was taken time τpg= τad. 5the equalization pressurizing (ep) step was taken time τep=0.5* τad. 6the feed pressurizing (fp) step was taken time τfp=0.5* τad. in the psa process, the product flowrate is not actually continuous, but was assumed to be continuous to simplify the design. as a result a factor, kc, the utilized time fraction for the product flow, was introduced and calculated from the following equation; ⁄ (5) the psa system approach introduced the product flow utilizes time fraction kc for different system arrangements, and the purge flow factor kp (fraction of product flow in a single column), as shown in fig. 3. fig. 3. psa system for the psa system, the product flowrate and productivity were calculated from the following equations; (6) (7) ⁄ (8) the recovery was difficult to calculate accurately because of intermediate steps and because the feed is not actually continuous. a case study of a psa process of 1 kg/h production of approximately 95% oxygen purity was used in the present study. four process variables were studied, the adsorption step time τad (1-5 minutes), pressure p (2-6 bar), utilized bed factor kb (0.5-0.9), and purge factor kp (0.1-0.5). z. a. abdel-rahman / iraqi journal of chemical and petroleum engineering91,9 (2018) 29-43 26 3results and discussion figures (4) and (5) show the effect of the adsorption step time, zeolite type and psa system arrangement on the process performance (weight of zeolite required or productivity), at constant values for p, kb & kp of 6 bar, 0.9, and 0.1, respectively. zeolite 13x only had an approximately 6% better performance than 5a zeolite. this is in agreement with data obtained by mofarahi & shokroo [23]. the product refill 4-steps psa process had an approximate 33% better performance than the pressure equalization 6-steps process. this is a novel point found by this work that has not been mentioned in the literature. increasing the adsorption step time (τad) from 1 to 5 minutes decreased the performance by an approximate factor of 5. the adsorption time was the most effective variable. the present work productivity range results (5-35 liter oxygen/kg zeolite h) are in agreement with most of the current literature. ad minute 0 1 2 3 4 5 6 m b k g 0 20 40 60 80 100 120 140 160 180 200 13x product refill 13x equalization 5a product refill 5a equalization fig. 4. effect of the adsorption step time, zeolite type and psa system on zeolite weight at p=6 bar, kb=0.9 & kp =0.1. ad minute 0 1 2 3 4 5 6 p r o d u c ti v it y li te r o 2 /k g z e o li te h 0 5 10 15 20 25 30 35 13x product refill 13x equalization 5a product refill 5a equalization fig. 5. effect of the adsorption step time, zeolite type and psa system on productivity at p=6 bar, kb=0.9 & kp =0.1 figure (6) shows the effect of the operating pressure (p) on the process productivity, at constant values for τad, kb and kp of 1 minute, 0.9, and 0.1, respectively. increasing pressure from 2 to 6 bars increased the performance by an approximate factor of 3. the operating pressure was the most effective variable after the adsorption step time variable (τad). this result is in agreement with several published works [19-22], whereas other works noted negative results for the effect of increasing pressure [1,911,23]. this contradiction may be due to the variables being highly interacted. p bar 1 2 3 4 5 6 7 p r o d u c ti v it y li te r o 2 /k g z e o li te h 5 10 15 20 25 30 35 13x product refill 13x equalization fig. 6. effect of the operating pressure on productivity at τad=1 minute, kb=0.9 & kp =0.1 figure (7) shows the effect of the utilized bed factor (kb) on the process productivity at constant values for τad, p and kp of 1 minute, 6 bars, and 0.1, respectively. increasing the utilized bed factor from 0.5 to 0.9 approximately doubled the performance. kb 0.4 0.5 0.6 0.7 0.8 0.9 1.0 p r o d u c ti v it y l it e r o 2 /k g z e o li te .h 10 12 14 16 18 20 22 24 26 28 30 32 13x product refill 13x equalizaion fig. 7. effect of the bed volume utilized factor on productivity at τad=1 minute, p=6 bar, & kp =0.1 z. a. abdel-rahman / iraqi journal of chemical and petroleum engineering91,9 (2018) 29-43 26 figure (8) shows the effect of the purge factor (kp) on the process productivity at constant values for τad, p and kb of 1 minute, 6 bars, and 0.9 respectively. increasing the purge factor from 0.5 to 0.9 decreased the performance by approximately half. kp 0.0 0.1 0.2 0.3 0.4 0.5 0.6 p r o d u c ti v it y l it e r o 2 /k g z e o li te h 10 12 14 16 18 20 22 24 26 28 30 32 13x product refill 13x equalization fig. 8: effect of the purge factor on productivity at τad=1 minute, p=6 bars, & kb =0.9 4conclusions 1the product refill 4-steps psa process had a 33% improved performance (weight of zeolite required or productivity) compared with the pressure equalization 6-steps process. this is a novel point found by the present study and has not reported in previous published works. 2zeolite 13x only had a 6% higher performance than 5a zeolite. 3the most effective variables were the adsorption step time and pressure. increasing the adsorption step time from 1 to 5 minutes decreased the performance by a factor of 5, and increasing the pressure from 2 to 6 bars increased the performance by a factor of 3. nomenclatures symbols kb bed volume utilized fraction kc psa system product flow utilized time fraction kp purge flow fraction kz adsorption constant, mole n2/kg zeolite. bar mb total zeolite weight, kg mb1 single column zeolite weight, kg n number of steps n number of columns p pressure, bar q equilibrium capacity, mole n2/kg zeolite qf feed flowrate, m 3 /h qp product flowrate, m 3 /h qp1 single column product flowrate, m 3 /h vb total zeolite bed volume, m 3 vb1 single column zeolite bed volume, m 3 yf feed oxygen fraction yp product oxygen fraction greek symbols ρb zeolite bed bulk density, kg/m 3 ρg gas density, kg/m 3 τ total cycle time, minute τad adsorption step time, minute τb breakthrough time, minute τdp depressurizing step time, minute τed equalization depressurizing step time, minute τep equalization pressurizing step time, minute τfp feed pressurizing step time, minute τi general step time, minute τpg purging step time, minute τpp product pressurizing step time, minute references [1] farooq, s.; ruthven, d. m.; & boniface, h. a., numerical simulation of pressure swing adsorption oxygen unit, chem. eng. sci., 44 (12), 2809-2816, 1989. [2] ruthven, d. m.; and farooq, s., air separation by pressure swing adsorption, gas sep. purif., 4, 141, 1990. [3] liow j., kenny c.n, the backfill cycle of the pressure swing adsorption process, aiche j. 36, 53, 1990. [4] zahur m., air separation on carbon molecular sieves 4a, and 5a zeolite by pressure swing adsorption, m.sc. thesis, king fahd university of petroleum & minerals, dhahran, saudi arabia, 1991. [5] chou, c., and huang, w., simulation of four bed pressure swing adsorption process for oxygen enrichment, ind. eng. chem. res., 33, 1250, 1994. [6] rege, s.u., and yang, r.t., limits for air separation by adsorption with lix zeolite, ind. eng. chem. res., 36, 5358-5365, 1997. [7] teague k. t., and edgar t. f., predictive dynamic model of a small pressure swing adsorption air separation unit, ind. eng. chem. res., 38, 37613775, 1999 . [8] shin, h.-s., kim, d.-h., koo, k.-k., lee, t.-s., performance of a two-bed pressure swing adsorption process with incomplete pressure equalization, adsorption 6, 233, 2000. z. a. abdel-rahman / iraqi journal of chemical and petroleum engineering91,9 (2018) 29-43 22 [9] mendes, a. m. m.; costa, c. a. v.; & rodrigues, a. e., analysis of nonisobaric steps in nonlinear bicomponent pressure swing adsorption systems, application to air separation, ind. eng. chem. res., 39, 138, 2000. [10] mendes a. m. m., costa c. a.v., rodrigues a. e., oxygen separation from air by psa: modeling and experimental results , separation and purification technology, 24, 173, 2001. [11] jee j. g., lee j. s., and lee c. h., air separation by a small-scale two-bed medical o2 pressure swing adsorption, ind. eng. ch.. res., 40, 3647-3658, 2001. [12] jee, j. g.; park, h. j. ; haam, s. j. ; lee, c. h. effects of nonisobaric and isobaric steps on o2 pressure swing adsorption for an aerator, ind. eng. chem. res., 41, 4383, 2002. [13] jee j. g., lee j. s., moon, h. m., & lee c. h., adsorption dynamic of air on zeolite 13x and cms beds for separation & purification, adsorption, 11, 415, 2005. [14] santos j. c., portugal a. f., magailaes f. d., and mendes a., simulation and optimization of small oxygen pressure swing adsorption unit, ind. eng. chem. res., 43, 8328-8338, 2004. [15] yuwen, z., yuyuan, w., jianying, g., jilin, z., the experimental study on the performance of a smallscale oxygen concentration by psa, separation and purification technology 42, 23–127, 2005. [16] ahari, j. s., pakseresht, s., mahdyarfar, m., shokri, s., zamani, y., pour, a. n. & naderi, f., predictive dynamic model of air separation by pressure swing adsorption, chem.eng. tech., 29(1), 50-58, 2006 [17] santos j. c., portugal a. f., magailaes f. d., and mendes a, optimization of medical psa units for oxygen production. ind., eng., chem., res. 45, 1085, 2006. [18] zahra, m.; jafar, t., & masoud, m., study of a four-bed pressure swing adsorption for oxygen separation from air, int. j. of chem. and biomolecular eng.1; 3, 2008. [19] mofarahi m., fathi l., and towfighi j., oxygen separation from air by four bed pressure swing adsorption, ind. eng. ch. res, 48(11)5439-5444, 2009. [20] beeyan , a. k.; singh, k.; vyas, r. k.; kumar, s.; & kumar, s., parametric studies and simulation of psa process for oxygen production from air, polish j. of chem. tech., 12, 2, 18-28, 2010. [21] abdel-rahman, z.a., mhdi, a.h., and ali, a.j., two spiral tubes pressure swing adsorption for oxygen separation from air, 1st national conf. for engineering sciences, 7-8 november 2012. [22] abdel-rahman, z.a., mhdi, a.h., & ali, a.j., study the behavior of long spiral tube adsorber for oxygen separation from air, eng. & tech. j., 31 (17), 2471, 2013. [23] mofarahi, m.; & shokroo, e. j., comparison of two adsorption processes for air separation using zeolite 5a and zeolite 13x, petroleum & coal, 55(3), 216, 2013. [24] smith, o. j., and westerberg, a. w., the optimal design of pressure swing adsorption systems, chem. eng. sci., 46, 12, 2967-2976, 1991. [25] ruthven, d. m.; farooq, s.; knaebel, k. s., pressure swing adsorption, vch publishers, new york, 1994. [26] perry, r. h., green, d. w., maloney, j. o., chemical engineers handbook, mcgraw-hill, 1997. [27] crittenden, b. and thomas, w.j., adsorption technology & design, butterworth-heinemann, oxford, 1998. ijcpe vol.9 no.3 (2008) iraqi journal of chemical and petroleum engineering vol.9 no.3 (september 2007) 37-41 issn: 1997-4884 computational analysis of the mixing zone in the combustion chamber of ramjet adil a. al-hemiri * and sa’ad a. fa’ek * chemical engineering department college of engineering university of baghdad – iraq abstract a theoretical analysis of mixing in the secondary combustion chamber of ramjet is presented. theoretical investigations were initiated to insight into the flow field of the mixing zone of the ramjet combustor and a computer program to calculate axisymmetric, reacting and inert flow was developed. the mathematical model of the mixing zone of ramjet comprises differential equations for: continuity, momentum, stagnation enthalpy, concentration, turbulence energy and its dissipation rate. the simultaneous solution of these equations by means of a finite-difference solution algorithm yields the values of the variable at all internal grid nodes. the results showed that increasing air mass flow (0.32 to 0.64 kg/s) increases the development of velocity profile due to the high turbulence generated resulting in very fast mixing and homogenous flow. and the occurrence of chemical reaction causes higher local temperature and composition resulting in faster development of the velocity profile keywords: oil non-premixed chemically reacting ducted flows, mixing of two streams, ramjet modeling. introduction increased interest in ramjet propulsion system with higher performance requirements and tighter constraints on system size and weight has led to the need for improved techniques for analyzing and designing such system. a critical requirement for achieving high system performance within specified geometric limits is an accurate description of the secondary combustor flow field, including the effect of the mixing zone and chemical reaction. in a conventional application (fig.1), the mixing zone is necessary for more complete combustion before the gases exit through the nozzle. it is important to be able to determine the combustion behavior within this region as a function of upstream conditions. a recent study (faek, 2004) gave a comprehensive survey on the subject and considered the effect of various parameters on the velocity profile. these parameters were: air mass flow rate, air to fuel ratio, working pressure, air and fuel temperatures. he showed that: increasing air mass flow increases the development of velocity profile due to the high turbulence generated resulting in very fast mixing and homogenous flow. increasing air and fuel temperature reduces the cooling effect of air and gives higher mixing temperature because it increases the thermal energy exchange between the air and fuel streams. increasing upstream combustor pressure increases the development of velocity profile due to the development of highly recirculating region. the fuel to air ratio has little effect on the mixing zone characteristics, since it only effect the inlet velocities of air and fuel thus it give the same profile and the mixing temperature. the best air mass flow was reported to be 0.64kg/s, upstream combustor pressure of 8 bar, air inlet temperature of 500k, fuel inlet temperature of 1100k and fuel to air ratio of 0.125 (faek,2004). university of baghdad college of engineering iraqi journal of chemical and petroleum engineering removal of asasbn sdfs fs f sf sdfsdfsdf fsdfsdfsdfs fsdfsdfsd 2 ijcpe vol.9 no.3 (2008) the purpose of this paper is to study the effect of air flow rate on the mixing zone velocity profile (for the two cases of reacting and non-reacting systems) by using a governing equations and solving them by a computer program developed for this goal. model overview the flow was assumed to be steady, two-dimensional, and subsonic. for simplicity, the value of specific heat (cp) was assumed to be constant although its dependence on temperature and/or composition could be easily included. a modified jones-launder,( jones and launder,1972; launder and spalding,1974) twoparameter turbulence model was incorporated to calculate the effective viscosity. it uses five empirical constants (table 1) and requires that two additional variables [turbulence kinetic energy (k) and turbulence dissipation rate ()] be evaluated. effective viscosity was calculated using the formulas μμμ teff  (1) where, ερ kcμ 2 μt  (2) for reacting flows, four species were considered: oxygen, nitrogen, fuel, and products. simple, one step, infinitely fast kinetics was assumed in which 1kg of fuel combines with i kg of oxidant to form (1+ i) kg of product without intermediaries (moult and srivatsa, 1977). fuel and oxygen, therefore, could not exist simultaneously, and the combustion process was mixing limited. the turbulent prandtl and schmidt numbers were taken equal to unity, and therefore, the turbulent lewis number was unity; the laminar prandtl number was also taken to be unity. the conservation equations for axisymmetrical flows with no tangential variations can be put into general form (khalil, e.e., spalding and whitelaw,1975).        s r r rrxx vr rr u x                             11 (3) where ψ stands for the dependent variables (u,v,k,,h, etc….) being considered (ψ=1 for continuity equation), ψ is the appropriate effective exchange coefficient for turbulent flow, and sψ as the "source term" (table 2). the energy equation in terms of stagnation enthalpy has no source terms since the turbulent prandtl and schmidt numbers were chosen equal to unity and radiative transport was neglected. thus, the stagnation enthalpy is given by   2vuhh 22  (4) where for non-reacting flows tch p (5) and for reacting flows  refpox ttciδηmh  (6) table (1) turbulence model constants (launder and spalding, 1974) constant value c1 1.44 c2 1.92 cμ 0.09 k 0.42 e 8.8   22.1ccckσ 9.0σσσ 2 1 μ12 2 ε fhk          ijcpe vol.9 no.3 (2008) table (2) governing equations parameters (launder and spalding, 1974) conse rvatio n of ψ γψ sψ mass 1 0 0 axial mome ntum u  eff                            x v r rrx p x u x effeff  1 radia l mome ntum v  eff 2 2 1 r v r u xr p r v r rr effeffeff                            kineti c energ y k   k eff g dissi pation rate     eff    21 cgc k  stagn ation enthal py h   h eff 0 mass fracti on of fuel m i   fu eff 0 mixtu re fracti on f f eff   0 special treatment near a wall to avoid the need for detailed calculations in the nearwall grid regions, algebraic relations are employed for the near wall grid nodes, which have to be spaced at such a distance from the neighboring walls that they lie within the so-called logarithmic layer. such relations are termed wall functions which are derived so as to reproduce identically the implications of the logarithmic profiles with uniform shear stress prevailing up to the near wall grid node, with generation and dissipation of energy are in balance at this locality (patankar and spalding,1970). the particular ones employed for the equation of the three velocity components, k and , are:      ν/ykecln κ 1 ρτ kc u p 21 p 41 μ w 21 p 41 μ p  (7)   21 μwp cρτk   (8) p 23 p 43 μ p yκ kc ε  (9) the solution procedure the set of differential equations are first reduced to finite-difference equations exhibiting "hybrid formulation of the coefficients", i.e., coefficient that contain combinations of the convective flux per unit mass f and the diffusive conductance. and then solved iteratively by "simple" procedure (patankar and spalding, 1972; patankar, 1980; versteeg and malalasekera, 1995). the grid arrangement for discretisation is as shown in figure (2). and the logic diagram for simple algorithm is given by figure (3), where the procedure steps are as given below: start initial guess of p*, u*, v*, φ*. step! solving discretised momentum equations, ai,j u*i,j = σ anb u*nb + ( p*i-1,j p*i,j ) ai,j + bi,j aiij v*i,j = σ anb v*nb + ( p*i,j-1 p*i,j ) ai,j + bi,j step 2: solving pressure correction equation, ai,j p'i,j = ai+1,j p'i+1,j + ai-1,j p'i-1,j + ai,j+1 p'i,j+1 + ai,j-1 p'i,j-1 + bi,j step 3: correction of pressure and velocities, pi,j = p*i,j + p'i,j ui,j = u*i,j + di,j (p'i-1,j p'i,j ) vi,j = v*i,j + di,j (p'i-1,j p'i,j ) step 4: solving the discretised equations for ρ and t, removal of asasbn sdfs fs f sf sdfsdfsdf fsdfsdfsdfs fsdfsdfsd 4 ijcpe vol.9 no.3 (2008) ai,j ρ i,j = ai+1,j ρ i+1,j + ai-1,j ρ i-1,j + ai,j+1 ρ i,j+1 + ai,j-1 ρ i,j-1 + bi,j ai,j ti,j = ai+1,j ti+1,j + ai-1,j ti-1,j + ai,j+1 ti,j+1 + ai,j-1 ti,j-1 + bi,j test for convergence:, if yes stop program, if no set: p* = p; u* = u; v* = v; ρ* = ρ; t* = t. return to step 1 results and discussion the effect of air mass flow rate on the combustor mixing zone was studied by using the computer program, under two conditions (inert and reacting flows), in which pressure values used was (8 bar) and inlet air mass flow rate are (0.32, 0.64 kg/s) inlet air temperature was about (500k), fuel inlet temperature was (1100k) and fuel to air ratio was (0.125). the results are shown in vector forms in figures below, where the radial (r) and axial (x) distances are in meter units. from fig. (4) it can be seen that the deflection of velocity is from the lower velocity stream to the higher velocity stream, i.e., from air stream to fuel stream where the fuel stream behaves as the main stream. in fig. (5), the fuel stream is deflected to air stream that give a recirculation region downstream of fuel and air inlets and the velocity profile has its nearly constant shape after the end of the recirculation region. this, also, leads to low local values of temperature profile due to the large local quantity of the air stream and because there is no chemical reaction. from this comparison it can see the effect of inlet air mass flow rate on the ramjet mixing zone flow properties at inert flow system and at constant other inlet flow conditions. considering fig. (6), it can be seen that the air stream is deflected to fuel stream and the fuel stream behaved as the main stream and because there is no recirculation region the velocity profile developed faster and began to have its constant shape. in fig. (7) it can be seen that the fuel stream is deflected to air stream and air stream behaved as the main stream in the flow field and recirculation region occurred down stream of the fuel inlet and the velocity profile begin to have its nearly constant shape at the end of the recirculation region. the chemical reaction gives a higher local temperature (since combustion is exothermic reaction) and a higher local axial velocity (due to thermal expansion of the product gases) than the inert flow case. it can be seen from fig. (4) and fig. (6) that the velocity profile is the same but the flow conditions are different because in fig.(4) the system is inert and there is no changing in the density of the mixing zone but for fig. (6) the reaction occurring give a high change in the temperature and composition that a homogenous distribution of the product makes the mixing zone length shorter. similar effect may be deduced by comparing fig. (5) and (7). fig.1: flow boundaries with symmetry for a ramjet. fig.2: grid arrangement n,n: north; s,s: south; w,w:west;e,e:east top-wall boundary air fue l s id e – w a ll b o u n d a ry o u tle t b o u n d a ry symmetry line boundary ijcpe vol.9 no.3 (2008) step 1: start step 2 step 3 step 4 convergence ? stop yes no p=p*, u=u*, v=v* ρ,= ρ*, t*=t figure (3); logic diagram for program “simple” initial guess: p*,u*,v*,ρ*, t* ρ,t p, u, v, ρ*,t* p* u*, v* fig.4: velocity vector plot at =0.125, ma =0.64 kg/s, pc=8bar, tf=1100k and ta= 500k, and inert flow system. fig.5:velocity vector plot at =0.125, ma =0.32 kg/s, pc=8bar, tf=1100k and ta= 500k, and inert flow system. fig.6: velocity vector plot at =0.125, ma =0.64 kg/s, pc=8bar, tf=1100k, ta= 500k, and reacting flow system. (2d) ½ 23 sep 2004 ½ 0 0.1 0.2 0.3 x 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1 r (2d) ½ 23 sep 2004 ½ (2d) ½ 22 sep 2004 ½ 0 0.1 0.2 x 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1 0.11 r (2d) ½ 22 sep 2004 ½ (2d) ½ 22 sep 2004 ½ 0 0.05 0.1 0.15 0.2 0.25 0.3 x 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1 r (2d) ½ 22 sep 2004 ½ removal of asasbn sdfs fs f sf sdfsdfsdf fsdfsdfsdfs fsdfsdfsd 6 ijcpe vol.9 no.3 (2008) figure 7 velocity vector plot at =0.125, ma =0.32 kg/s, pc=8bar, tf=1100k, ta= 500k, and reacting flow system. conclusions a computer program has been developed for the analysis of ramjet mixing zone combustor. and comparison between the results at different input has shown the effect of the parameters selected in this study on the mixing zone characteristics of ramjet combustor. reducing air mass flow rate will reduce the cooling effect of air stream and give higher mixing temperature. and increasing it will cause the velocity profile to develop faster. the difference between the performance with inert or reacting systems is that for the reacting system, the reaction causes changes in temperature and composition leading to a homogenous distribution and hence a faster development of velocity profile, i.e., shorter length of mixing zone. nomenclature c1,c2, cμ k-ε model empirical constants (table 1) cp specific heat at constant pressure. e integration constant in wall function=9 g generation term for kinetic energy of turbulence. h stagnation enthalpy h  enthalpy k turbulence kinetic energy kp wall function turbulence kinetic energy ma inlet air mass flow rate pc up stream combustor pressure r radial distance s source term of the general governing equation ta inlet air temperature tf inlet fuel temperature u axial velocity up wall function axial velocity v radial velocity x axial distance yp wall function distance variable greek letters γ effective diffusion coefficient  dissipation rate of turbulence kinetic energy  p wall function dissipation rate к von karman constant  air to fuel ratio μ viscosity μ t turbulent viscosity μ eff effective viscosity ψ general dependent variable ρ density σ prandtl or schmidt number τ shear stress reference 1. faek, s. a., "analysis of the mixing zone in the combustion chamber of ramjet" m. sc thesis, baghdad university, 2004. 2. jones, w.p., and launder, b.e., "the prediction of laminarization with a two-equation model of turbulence", international journal of heat and mass transfer, vol.15, pp.301-314, feb. 1972. 3. khalil, e.e., spalding, d.b., and whitelaw, j.h., "the calculation of local flow properties in two dimensional furnaces", international journal of heat and mass transfer, vol. 18, pp. 775-791, 1975. 4. launder, b.e., and spalding, d.b., "the numerical calculation of turbulent flows", computer methods in applied mechanics and engineering, vol.3, no.2, pp. 269-289, 1974. 5. moult, a. and srivatsa, s.k., "a computer code for axi-symmetric combustion chambers", cham, 1977. 6. patankar, s.v., and spalding, d.b., "heat and mass transfer in boundary layers", 2nd edition, london, 1970. 7. patankar, s.v., and spalding, d.b.,"a calculation procedure for heat, mass, and momentum transfer in three-dimensional parabolic flows", international journal of heat and mass transfer, vol.15, pp.17871806, 1972. 8. patankar, s,v., "numerical heat transfer and fluid flow", hemisphere publishing corporation, taylor & francis group, new york, 1980. 9. versteeg, h.k., and malalasekera, w., "an introduction to computational fluid dynamics: the finite-volume method", longman group ltd, 1995. (2d) ½ 22 sep 2004 ½ 0 0.1 0.2 x 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1 0.11 r (2d) ½ 22 sep 2004 ½ iraqi journal of chemical and petroleum engineering vol.17 no.4 (december 2016) 7182 issn: 1997-4884 osmotic membrane bioreactor for oily wastewater treatment using external & internal configurations ahmed faiq al-alalawy*, talib rashid abbas** and hadeer kadhim mohammed* *chemical engineering department college of engineering university of baghdad ** environment and water directorate ministry of science and technology email: ahmedalalawy@yahoo.com, talibrshd@yahoo.com and hadeer_master@yahoo.com abstract the present work aims to study the treatment of oily wastewater by means of forward osmosis membrane bioreactor process. side stream (external) configuration and submerged (internal) configuration of osmotic membrane bioreactor were performed and investigated. the experimental work for each configuration was carried out continuously over 21 days. the flux behavior of forward osmosis membrane in an osmotic membrane bioreactor (ombr) was investigated, using nacl as the draw solution and cta as fo membrane. the effect of mixed liquor suspended solids (mlss) concentration and tds accumulation of bioreactor on water flux and membrane fouling behaviors was detected. the accumulation and rejection of nutrients in the bioreactor (nitrate, cod, and phosphate) were investigated over the days of the experiment. water flux and membrane fouling were not significantly affected by mlss concentration at low level and this effect increase with increasing mlss concentration (4000–10000 mg/l). besides, water flux was severely affected by elevated salinity of the aeration tank. ombr showed high removal of cod (96%) and fo membrane revealed high retention of phosphate (97%) but retention for nitrate was relatively low (72%). the sparingly soluble salts in the influent, bioreactor, draw solution, and ro effluent were detected through the experiment. the results showed flux decline with time to about 47% from the initial flux and two osmotic backwashing were applied at day 7 and 14 during the operation and the flux restored approximately 30% of its loss. side stream and submerged configurations revealed nearly similar response over the experiments while side stream module showed better water flux (7.0 lmh) than submerged (6.1 lmh). the results showed that the concentration of inorganic ions is below the limits that may cause severe scaling. key words: forward osmosis, water flux, fouling, osmotic membrane bioreactor. introduction generally, wastewater comes from two major sources: human sewage and process waste from manufacturing industries including oil refineries. oil, grease and hydrocarbons are the essential contaminants of oil refinery wastewater. innovative processes based on membranes coupled with biouniversity of baghdad college of engineering iraqi journal of chemical and petroleum engineering mailto:ahmedalalawy@yahoo.com mailto:talibrshd@yahoo.com mailto:hadeer_master@yahoo.com osmotic membrane bioreactor for oily wastewater treatment using external & internal configurations 72 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net treatment for wastewater, especially oily wastewater treatment were recently proved as promising technologies to produce high quality water that can be reused as well as free of toxic and harmful constituents for the living organisms when discharged to the environment. membrane bioreactor (mbr) innovation initially studied and reported for wastewater treatment application around 40 years ago, is presently effectively utilized in municipal and industrial wastewater treatment [1–6]. mbr has become well-known because of some particular favorable circumstances contrasted with traditional wastewater treatment processes, such as, decreased footprint, low creation of excess sludge [2], great effluent quality and high concentration of sludge [1]. the major drawback of this process is high energy consumption during application due to extra aeration required for mixing as well as to control membrane fouling [4, 7, 8]. two configurations were used in mbr process: external and internal configuration. in external mode, the membrane cited outside the bioreactor, while in internal mode, the membrane cited inside the bioreactor. as of late there has been expanding attention for a novel mbr which incorporates forward osmosis (fo) and the biological procedure for wastewater treatment in a technique usually known as osmotic membrane bioreactor (ombr). ombr is a perfect technology which include multi-barrier that can be utilized for indirect and direct reuse applications of potable water [9–15]. forward osmosis (fo) membranes utilized in ombrs are applied to withdraw water through a dense, semi-permeable layer from a low-salinity waste feed into a highsalinity draw solution (ds). in some applications an ro process is utilized to re-concentrate the diluted draw solution and at the same time produce high quality water. osmotic pressure difference over fo membrane between feed (activated sludge) and the draw solution is the driving force in ombr. the essential benefits of using fo membrane over other membrane separation technologies with respect to wastewater treatment are the low fouling propensity and the perfect rejection of macromolecules, trace organic compounds torcs, and ions [16–24]. previous researches have highlighted the points of interest and uses of ombrs [9-13]; besides, they have additionally identified the accumulation of total dissolved solids (tds) and other dissolved components in the aeration tank as an essential disadvantage of the ombr operation [9, 14, 15]. the high rejection of tds and nutrients by fo membrane lead to accumulation of these constituents in the bioreactor as well as reverse salt flux by diffusion from the draw solution into the bioreactor. the tds and hence salinity of activated sludge increases with time which in parallel decreases the osmotic pressure difference over the membrane (reduce driving force and hence water flux) and can unfavorably influence microbial activity and usefulness in the bioreactor which would advance effect membrane fouling [25, 26]. besides, the interactions of the inorganic particles (particularly divalent cations) as well as organic foulants, and additionally the scaling of low dissolvable salts (e.g. gypsum, calcium carbonate and calcium phosphate [30]) under relative high strength of ions offer ascent to higher complex fouling issues on fo membranes [27–29]. the aim of the current work is to investigate the feasibility of ombr process, which combines fo process and mbr process, in treating oily wastewater and produce high quality water. the ombr process imply http://www.iasj.net/ ahmed faiq al-alalawy, talib rashid abbas and hadeer kadhim mohammed -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 73 investigation of system configuration (side stream and submerged), mlss concentration, and fo membrane fouling and backwashing, as well as nutrient removal and accumulation. moreover, the effects of salt accumulation on biological treatment performance with respect to water flux will also be investigated. materials and methods the ombr process includes treatment of oily wastewater by means of two configurations, side stream and submerged as shown in figures 1 and 2. using reactor with 8 l total volume for submerged and 3l for side stream contain an air distributor connected with blower to supply o2 at 4 l/min flow rate which is required for growing of microorganisms m a l concentration was used as draw solution and l min feed and draw solutions flow rate temperature of both feed and draw solutions. the membrane was asymmetric cellulose triacetate (cta) fo membrane delivered by hti albany, or. the process carried out without usage of mesh spacer in the fo cell to reduce accumulation of biomass on the membrane and cause fouling issues. the feed used in the present study was brought from alduara refinery (the effluent stream of daf process in wastewater treatment unit) and the activated sludge brought from aeration tank at the same unit. the level of activated sludge in the reactor was kept constant at 20 cm height for submerged (5 l of activated sludge (as)) and 15 cm height for side stream( 3 l of as) by utilizing float inside the reactor. the float is connected to a supply tank contain oily wastewater to compensate the reactor with the lack in water due to permeation. the supply tank located in a higher place than reactor (70 cm) to impart feed without need of pump as illustrated in figures 1 and 2. the duration of experiment for each configuration of biological stage was 21 days included two osmotic backwashing at day 7 and day 14 of the experiment. sludge was wasted manually using a graduated cylinder from the bioreactor with rate of 150 ml/day for side stream mode and 250 ml/day for submerged mode starting on day 7 of the continuous operation, and the computed solids retention time (srt) according to this wasting rate is 20 days. the concentration of draw solution was kept constant throughout the run using vessel with flow regulator fixed at the bottom which contains concentrated draw solution (200 g/l). the concentrated draw vessel was placed over the draw solution vessel as shown in figures 1 and 2. concentrated draw solution was flow as drops to balance the dilution of draw solution by water permeation and this flow was modified daily according to dilution rate. samples of draw solution was taken periodically and treated in ro system which manufactured by sterlitech, ge osmonics, and usa. polyamide membrane were used with dimension of 305 x 305mm. five liters of draw solution were processed for each run in this system with concentration of 35 g/l of nacl. the applied pressure was 50 bar and the permeate flux was 25 lmh. the ro permeate was collected and submitted to several tests such as: conductivity, cod, and ions concentration by means of uv spectrometer and flame photometer to evaluate permeate quality (treated water). the ro system was located at ministry of science and technology / environmental and water directorate. samples were taken and analyzed every five days from feed tank; bioreactor, draw solution, and ro permeate. http://www.iasj.net/ osmotic membrane bioreactor for oily wastewater treatment using external & internal configurations 74 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net draw solution bioreactor 32g heater cool heater cool temp temp waste water press air pump fo cell stand concentrated ds rorameter pump balance air diffuser conductivity level float supply tank conductivity fig. 1: schematic diagram of side stream osmotic membrane bioreactor process draw solution 32g heater cool temp temp waste water air pump stand concentrated ds balance air diffuser conductivity heater cool conductivity fig. 2: schematic diagram of submerged osmotic membrane bioreactor process results and discussions 1. effect of mlss concentration the influence of mixed liquor suspended solids (mlss) concentration with respect to water flux using side stream configuration is shown in figure 3. three concentrations of mlss were tested such as 4000, 7000, and 10000 mg/l. by increasing concentration of mlss the water flux decline had become more severe with time due to increase in concentration of biomass and hence more tendency of membrane fouling. this outcome is compatible with http://www.iasj.net/ ahmed faiq al-alalawy, talib rashid abbas and hadeer kadhim mohammed -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 75 conventional membrane bioreactor (mbr) process [1, 4]. it was documented that membrane fouling resistance is increased proportionally with mlss concentration in traditional mbr. the reason for this result is due to high mlss concentration of activated sludge contains excess foulants and hence more intense fouling. figure 3 shows low effect of mlss on water flux and this effect increase with increasing mlss concentration. fig. 3: influence of mlss concentration on flux decline with time 2. water flux the osmotic membrane bioreactor (ombr) process was operated with fixed ds concentration which is approximately 35 g/l (0.6 m). water flux as a function of time over the duration of experiments, which is 21 days, is shown in figure 4. throughout ombr testing, the fo membrane was refreshed by osmotic backwashing process on days 7 and 14 of operation. the initial water flux for side stream mode was approximately 7.0 lmh as illustrated in figure 4 and for submerged module, the initial water flux was nearly 6.0 lmh as shown in figure 5. for both configurations, the initial flux is followed by steady decrease in flux over 7 days of operation. the decline in flux might be attributed to decrease in osmotic driving force as well as membrane fouling. the decrease in osmotic driving force across fo membrane was due to increase in bioreactor salinity from approximately 1.0 g/l to 7.0 g/l tds as illustrated in figure 6. the salt accumulation in the aeration tank was due to salts incoming with the influent to the bioreactor as well as diffusion of salts to the bioreactor from ds tank (reverse salt flux). the ds concentration over the period of 21 days of operation was kept constant. the difference in concentration across the fo membrane reduced from 35 g/l to 28 g/l during the experiment. the influence of fouling on membrane activity with respect to flux decline was illustrated between day 7 and 14 as shown in figures 4 and 5 for submerged and side stream configurations respectively, where cleaning take place by osmotic backwashing. figures 6 and 7 show that after day 7 of operation, the tds of the bioreactor is nearly stable due to starting of daily wasting from the bioreactor at this period. the increase in salinity (tds) of the bioreactor for the first 7 days was more than five times of the initial value (1.09 g/l to 5.52 g/l), while for the next seven days after begin of sludge wasting, the salinity of the bioreactor was increased by solely 20% (5.52 g/l to 6.75 g/l). the excess salts accumulated in the bioreactor were withdrawn with daily wasting. this case indicates that the dropping in flux throughout operation was due to membrane fouling not to variance in driving force. figures 8 and 9 show and summarize the outcomes of the ombr experiments which performed to study the fouling of membrane and effect of osmotic backwashing on flux behavior at day 7 and 14 of continuous operation for side stream and submerged configurations. the left and right bars of each pair show the effect http://www.iasj.net/ osmotic membrane bioreactor for oily wastewater treatment using external & internal configurations 76 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net of membrane fouling and osmotic backwashing on water flux, respectively. after day 7 of process, the water flux reduced by approximately 47% from the initial flux of new membrane. after osmotic backwashing, the flux restored approximately 30% of its loss, with an overall of 17% loss in water flux which may attributed to irreversible fouling. the second backwashing at day 14 of operation show that the water flux reduced by 23% from day 7 and the second backwashing restore about 87% of the loss in flux. the reduce in flux decline after day 7 is due to daily wasting of activated sludge from the bioreactor which reduce the accumulation of salts and hence enhancing osmotic pressure difference over the membrane. this state gives a suggestion that after a state of irreversible fouling, which is occurring in the first 7 days, subsequent behavior of fouling become more reversible which is consistence with previous studies [9, 14]. the water flux for submerged mode (6 lmh) was less than external mode (7 lmh). the difference in flux between two modes may be due to accumulation of foulants on the active layer of membrane forming thin layer of biofoulants fig. 4: water flux over the course of 21 days of ombr for side stream mode fig. 5: water flux over the course of 21 days of ombr for submerged mode fig. 6: bioreactor salinity over the course of 21 days of operation for side stream mode fig. 7: bioreactor salinity over the course of 21 days of operation for submerged mode fig. 8: effect of membrane backwashing on water flux for side stream mode http://www.iasj.net/ ahmed faiq al-alalawy, talib rashid abbas and hadeer kadhim mohammed -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 77 fig. 9: effect of membrane backwashing on water flux (submerged mode) the aeration technique, especially in submerged configuration, is an important factor in fouling control. the rate of air flow utilized in this study was 4 l/min and the air diffuser was fixed in line with membrane with sufficient coarse bubbles which provide scouring of the membrane surface and prevent fouling. therefore thin layer was formed on the membrane which caused a low resistance to water flux. another reason of severe membrane fouling through ombr process is the accumulation of sparingly soluble salts in the aeration tank. the concentration of basic ions in the bioreactor was measured on four occasions over ombr process and the results are listed in table 1. the values of ions in this table were implemented in rosa software to find out the tendency of caco3 precipitation in the bioreactor by knowing value of langelier saturation index (lsi). the value of lsi should be less than one to avoid scaling. figure 10 shows the magnitude of lsi value with time. lsi value was increased from -0.13 to 0.47 after 7 days of operation while there was slow increase in lsi after day 7 due to removing of inorganic ions through wasting. the values of lsi, after 21 days of continuous operation, are less than 1.0 which is consistence with previous studies [33-36]. although this value of lsi reveals a slight tendency for caco3 precipitation, this precipitation may occur in the activated sludge rather than on the membrane. figure 11 shows that the concentration of caso4 after 21 days of ombr process is below the saturation limit and needs no additives or anti-scalants for scaling control. fig. 10: langelier saturation index (lsi) for the bioreactor change with time fig. 11: saturation percentage of caso4 over the course of operation table 1: ions concentration in the bioreactor ions ion concentration (mg/l) day-1 day-7 day14 day21 na 148 662 796 833 ca 56 235 311 357 mg 65 304 346 388 k 2.6 14.5 16.0 18.3 so4 139 635 790 854 cl 123 588 738 890 no3 10.5 25.2 30.6 15.6 po4 1.5 6.8 7.5 7.9 http://www.iasj.net/ osmotic membrane bioreactor for oily wastewater treatment using external & internal configurations 78 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net 3. nutrient rejection and accumulation phosphate the values of phosphate concentration during the course of operation in the ro permeate and ds was under the detection limits. due to high membrane rejection of phosphorus, it will steadily accumulate in the bioreactor over the ombr operation. after day 7 of process and when sludge wasting is started, the phosphorus concentration is almost leveled off as shown in figures 12 and 13 for the two configurations. fig. 12: concentration of phosphate in bioreactor as a function of operation days for side stream mode fig. 13: concentration of phosphate in the bioreactor as a function of operation days for submerged mode the phosphorus rejection via fo membrane was about 98% and the total system (fo + ro) rejection was more than 99%. these results were consistence with earlier studies [31, 32] which achieved more than 99% rejection of phosphate. nitrate from the ionic analysis of aeration tank, draw solution, and ro permeate, the nitrate concentration was found relatively high for the first 14 days of continuous operation as shown in figures 14 and 15 for side stream and submerged configuration respectively. the high concentration of nitrate is proof of nitrification process (ammonia oxidation) and the denitrification process (nitrate reduction) is limited within this period. during the third week of the ombr operation, the concentrations of nitrate begin to decrease with time which may be attributed to the increase in bioreactor accumulated salinity. the nitrification process is controlled by bacteria called ammonia oxidizing bacteria (aob). from the analytical results, the aob activity was influenced and inhibited by increasing bioreactor accumulated salinity. during the course of 21 days of operation, the nitrate concentration in the draw solution increased with time which is attributed to diffusion of nitrate through the fo membrane from the bioreactor which is consistence with earlier studies [31, 33]. the low rejection of nitrate (72%) by cta fo membrane is drawback which should be considered in such processes. the nitrate concentration in the ro permeate was relatively low and below the maximum permissible limit of nitrate in drinking water concentration (10 mg/l) which represented as a toxic and hazardous component for health according to environmental protection agency, epa, which make the water convenient for reuse in most applications. http://www.iasj.net/ ahmed faiq al-alalawy, talib rashid abbas and hadeer kadhim mohammed -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 79 fig. 14: concentration of nitrate in the bioreactor, draw solution, and ro permeate as a function of operation days for side stream mode fig. 15: the concentration of nitrate in the bioreactor, draw solution, and ro permeate as a function of operation days for submerged mode cod the cod concentration in the influent, bioreactor, draw solution, and ro permeate were illustrated in figures 16 and 17 for the side stream and submerged, respectively. the cod concentration in the bioreactor was observed to be increased slightly during the ombr operation and this might attributed to the increasing salinity of the activated sludge which affects the biological activity and degradation performance. the cod concentration in the ro permeate was less than 10 mg/l and this result show the advantage of utilizing multi-barrier technology like ombr. fig. 16: concentration of cod in the influent, bioreactor, draw solution, and ro permeate as function of operation days for side stream mode fig. 17: the concentration of cod in the influent, bioreactor, draw solution, and ro permeate as function of operation days for submerged mode conclusions this study provides useful information for the determination of appropriate parameters in ombr operation as well as better understanding of ombr process with applying two configurations, side stream and submerged. initial water flux for side stream mode was 7.0 lmh, while initial flux for submerged mode was nearly lmh water flux and membrane fouling were showed less influenced by mlss concentration at certain level (4000 mg/l) and this effect increase with increasing mlss concentration. ombr system exhibited excellent removal/rejection http://www.iasj.net/ osmotic membrane bioreactor for oily wastewater treatment using external & internal configurations 80 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net of nitrogen, phosphorus, and cod from the analysis results which conducted for influent and ro permeate. the average removal of nitrogen, phosphorus, and cod during the ombr exceeded 72%, 97%, and 96%, respectively, for both configurations. despite the low nitrogen removal compared to the phosphorus and cod, its concentration in the ro permeate was less than 10 mg/l for the ombr process. accumulated sparingly soluble salts in the bioreactor were increased over the course of 21 days to a value below the limits that may cause severe membrane scaling as determined by langelier saturation index (lsi) and caso4 saturation. the results revealed sharp flux decline with time for first week for both modes and this decline become less severe when start wasting. osmotic backwashing found to be efficient way for membrane refresh. acknowledgements the authors acknowledge the support of the chemical engineering department, college of engineering, university of baghdad. the authors also acknowledge the water and environment directorate, ministry of science and technology. references 1. m. kraume, a. drews, (2010), membrane bioreactors in wastewater treatment — status and trends, chem. eng. technol. 33, 1251–1259. 2. t. oliver, h. rania, a. joo, (2016), membrane bioreactor (mbr) technology for wastewater treatment and reclamation: membrane fouling, membranes, 6(2), 33. 3. a. drews, (2010), membrane fouling in membrane bioreactors— characterisation, contradictions, cause and cures, j. membr. sci. 363, 1–28. 4. r.s. trussell, r.p. merlo, s.w. hermanowicz, d. jenkins, (2007), influence of mixed liquor properties and aeration intensity on membrane fouling in a submerged membrane bioreactor at high mixed liquor suspended solids concentrations, water res. 41, 947–958. 5. l. duan, i. moreno-andrade, c. huang, s. xia, s.w. hermanowicz, (2009), effects of short solids retention time on bacterial community in a membrane bioreactor, bioresour. technol. 100, 3489–3496. 6. j. ji, j. qiu, n. wai, f.s. wong, y. li, (2010), influence of organic and inorganic flocculants on physical–chemical properties of biomass and membrane-fouling rate, water res., 44, 1627–1635. 7. j.c.t. lin, d.j. lee, c. huang, (2010), membrane fouling mitigation: membrane cleaning, sep. sci. technol., 45, 858–872. 8. m.y. chen, d.j. lee, z. yang, x.f. peng, j.y. lai, (2006), fluorescent staining for study of extracellular polymeric substances in membrane biofouling layers, environ. sci. technol., 40, 6642–6646. 9. a. achilli, t.y. cath, e.a. marchand, a.e. childress, (2009), the forward osmosis membrane bioreactor: a low fouling alternative to mbr processes, desalination, 239, 10–21. 10. a. alturki, j. mcdonald, s.j. khan, f.i. hai, w.e. price, l.d. nghiem, (2012), performance of a novel osmotic membrane bioreactor (ombr) system: flux stability and removal of trace organics, bioresour. technol., 113, 201–206. 11. e.r. cornelissen, d. harmsen, k.f. de korte, c.j. ruiken, j.j. qin, h. oo, l.p. wessels, (2008), membrane fouling and process http://www.iasj.net/ ahmed faiq al-alalawy, talib rashid abbas and hadeer kadhim mohammed -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 81 performance of forward osmosis membranes on activated sludge, j. membr. sci., 319, 158–168. 12. m.s. nawaz, g. gadelha, s.j. khan, n. hankins, (2013), microbial toxicity effects of reverse transported draw solute in the forward osmosis membrane bioreactor (fo-mbr), j. membr. sci., 429, 323–329. 13. h. zhang, y. ma, t. jiang, g. zhang, f. yang, (2012), influence of activated sludge properties on flux behavior in osmosis membrane bioreactor (ombr), j. membr. sci., 390, 270–276. 14. j.s. zhang, w.l.c. loong, s.r. chou, c.y. tang, r. wang, a.g. fane, (2012), membrane biofouling and scaling in forward osmosis membrane bioreactor, j. membr. sci., 403, 8–14. 15. m. eyvaz, t. aslan, s. arslan, e. yüksel & i̇ koyuncu (2 ), recent developments in forward osmosis membrane bioreactors: a comprehensive review, desalination and water treatment, 43, 1–36. 16. a.a. alturki, j.a. mcdonald, s.j. khan, w.e. price, l.d. nghiem, m. elimelech, (2013), removal of trace organic contaminants by the forward osmosis process, sep. purif. technol., 103, 258–266. 17. n.t. hancock, p. xu, d.m. heil, c. bellona, t.y. cath, (2011), comprehensive benchand pilot scale investigation of trace organic compounds rejection by forward osmosis, environ. sci. technol., 45, 8483–8490. 18. x. jin,j.h. shan, c. wang, j. wei, c.y.y. tang, (2012), rejection of pharmaceuticals by forward osmosis membranes, j. hazard. mater., 227, 55–61. 19. r.v. linares, v. yangaliquintanilla, z.y. li, g. amy, (2011), rejection of micropollutants by clean and fouled forward osmosis membrane, water res., 45, 6737–6744. 20. n.t. hancock, p. xu, m.j. roby, (2013), towards direct potable reuse with forward osmosis: technical assessment of long-term process performance at the pilot scale, j. membr. sci., 445, 34–46. 21. n.t. hancock, t.y. cath, (2009), solute coupled diffusion in osmotically driven membrane processes, environ. sci. technol., 43, 6769–6775. 22. t.y. cath, a.e. childress, m. elimelech, (2006), forward osmosis: principles, applications, and recent developments, j. membr. sci., 281, 70–87. 23. c. klaysom, t.y. cath, t. depuydt, i.f.j. vankelecom, (2013), forward and pressure retarded osmosis: potential solutions for global challenges in energy and water supply, chem. soc. rev., 42, 6959–6989. 24. n.t. hancock, n.d. black, t.y. cath, (2012), a comparative life cycle assessment of hybrid osmotic dilution desalination and established seawater desalination and wastewater reclamation processes, water res., 46, 1145–1154. 25. a. uygur, (2006), specific nutrient removal rates in saline wastewater treatment using sequencing batch reactor, process biochem., 41, 61–66. 26. l. ye, c.y. peng, b. tang, s.y. wang, k.f. zhao, y.z. peng, (2009), determination effect of influent salinity and inhibition time on partial nitrification in a sequencing batch reactor treating saline sewage, desalination, 246, 556–566. 27. d. xiao, c.y. tang, j. zhang, w.c.l. lay, r. wang, a.g. fane, (2011), modeling salt accumulation in osmotic membrane bioreactors: http://www.iasj.net/ osmotic membrane bioreactor for oily wastewater treatment using external & internal configurations 82 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net implications for fo membrane selection and system operation, j. membr. sci., 366, 314–324. 28. s. zou, y. gu, d. xiao, c.y. tang, (2011), the role of physical and chemical parameters on for ward osmosis membrane fouling during algae separation, j. membr. sci., 366, 356–362. 29. p. van den brink, a. zwijnenburg, g. smith, h. temmink, m. van loosdrecht, (2009), effect of free calcium concentration and ionic strength on alginate fouling in cross-flow membrane filtration j membr sci 345, 207–216. 30. c.b. ersu, s.k. ong, e. arslankaya, y.w. lee, (2010), impact of solids residence time on biological nutrient removal performance of membrane bioreactor, water res., 44, 3192– 3202. 31. guanglei qiu, yen-peng ting, (2014), short-term fouling propensity and flux behavior in an osmotic membrane bioreactor for wastewater treatment. desalination, 332, 91–99. 32. wenchao xue, tomohiro tobino, fumiyuki nakajima, kazuo yamamoto, (2015), seawaterdriven forward osmosis for enriching nitrogen and phosphorous in treated municipal wastewater: effect of membrane properties and feed solution chemistry, water research, 69, 120-130. 33. w. ryan, a. holloway, s. andrew wait a, aline fernandes da silva, (2015), long-term pilot scale investigation of novel hybrid ultrafiltration-osmotic membrane bioreactors, desalin., 363,64-74. 34. v. parida, h.y. ng, (2013), forward osmosis organic fouling: effects of organic loading, calcium and membrane orientation, desalination, 312, 88–98. 35. b. mi, m. elimelech, chemical and physical aspects of organic fouling of forward osmosis membranes, j. membr. sci. 320 (2008) 292–302. 36. b. mi, m. elimelech, organic fouling of forward osmosis membranes: fouling reversibility and cleaning without chemical reagents, j. membr. sci. 348 (2010) 337–345. http://www.iasj.net/ iraqi journal of chemical and petroleum engineering vol.17 no.3 (september 2016) 8390 issn: 1997-4884 addition of super absorbent polymer for upgrading of cement quality in iraqi oil wells dhorgham skban ibrahim and faleh h. m. almahdawi petroleum engineering department, college of engineering, university of baghdad, iraq abstract this study focuses on the use of an optimum amount of sodium polyacrylate (sp) for designing cement slurry with the high performance of rheological properties and displacement efficiency. a laboratory study has been carried out on the cement slurry which prepared with sp as superabsorbent polymer. sp has been providing an internal water source that helps in the hydration process, and curing and ultimately increases the cement strength. also improves the cement performance by improving the cement stability. several batches were prepared to determine the proper amount of sp to add it in the cement slurry. also, we studied its effect on cement density, amount of free water in order to observe the rheological properties, and thickening time. results indicate that the designed cement rheological properties are directly influenced by the shear rate and shear stress on the mix and pump of the cement with the increase of the sp concentration for the rheological improvement. laboratory data are presented to highlight polyacrylate’s positive effect on compressive strength, fluid loss control, and free water. keywords: sodium polyacrylate, cement additive, cement slurry, rheological properties, superabsorbent polymer. introduction oil well cementing is the placement of a cement slurry in the annulus space between the well casing and the geological formations surrounding to the well bore to form a solid mass which has supporting and sealing properties. when a certain section of the depth of an oil or gas well has been drilled successfully, the drilling fluid filtrate will penetrate into the formation from a few inches to several feet which cause interaction with the formation minerals in the producing horizons, and the formation of the drilling mud cake cannot permanently prevent the well bore from collapsing. therefore, oil well cementing was introduced with a number of objectives [1]: (i) protecting oil producing zones from salt water invasion. (ii) protecting the well casing from exposure to collapse pressure. (iii) protecting well casings from wear and corrosion. (iv) reducing the risk of formation water contamination by oil, gas or salt water. (v) providing isolation zone of different underground formations in order to prevent the exchange of gas or university of baghdad college of engineering iraqi journal of chemical and petroleum engineering addition of super absorbent polymer for upgrading of cement quality in iraqi oil wells www.iasj.netavailable online at: 6) 201 september( 3no. 7ijcpe vol.1 48 fluids among different geological formations. in addition, to prevent their exposure to severe temperature, corrosive fluids, and over pressured formations. the development of iraqi oil industry during the last two decades has led to introduce new oil wells in the south and north iraqi oil fields. some of the new oil wells were conducted using normal cement quality in cementing operation. the faced problems in cementing operation which is a very important level to keep casing save. these problems are related to cement quality because after a period of time the casing severe from corrosion because of bad quality of cement. the main purpose of cementing is to support casing and to isolate zones so it is important to make a strong sheath between the casing and the formation without fractures happened. the use of normal cement quality makes a bad cement bond quality and shows a significant amount of mud losses during drilling through some of the carbonate formations. as a result, it was recommended to use high quality cement instead of the current cement and additives were recommended to be added to improve the quality of the cementing operation. a good cementing operation makes the cement characterized with high consistency, homogeneity, impermeability, and adhesively . therefore, we will try to develop poor cement quality to good quality by adding superabsorbent polymer which is sodium polyacrylate that working to improve the cement quality and properties like stability of cement and cement strength and reduce leaking of water from cement slurry and reduce initial setting time and final setting time of cement slurries [2, 3]. figure 1 shows a schematic simulation of the zb229 oil well cementing process. fig. 1: schematic simulation of the oil well cementing process in southern iraq (zb 229) http://www.iasj.net/ dhorgham skban ibrahim and faleh h. m. almahdawi 48 )6201september ( 3no. 17ijcpe vol. www.iasj.netonline at: available sodium polyacrylate is a superabsorbent polymer has the ability to absorb water, increase viscosity, protection of producing formation and it can use as a thickening agent which can increase the viscosity of a liquid. it is used in the manufacture of glass, binders, adhesives, absorbents, coatings, and fake snow [4]. a sodium polyacrylate polymer belongs to a group of polymers which could be characterized as plastics, transparency and resistance to breakage and elasticity. all these characterizations make the authors used this material to improve the cement quality used in oil wells. experimental work measurement methods the following tests are very important to evaluate cement quality: 1. initial setting time initial setting time is measured by vicat needle apparatus. this test can carry out by measurement the depth of penetration of the needle has (1 mm) diameter into the cement slurry weight of 300 gm formed of water and cement with a 0.5 water to cement weight ratio at a temperature of 140 o f. initial setting time is the time required to make slurry has certain consolidate that make the needle of the apparatus does not penetrate the sample completely, but (3-5 mm) is not penetrated above the lower base. the cement is considered good quality cement if initial setting time is between (95–140) minute from the beginning of cement preparation. 2. final setting time final setting time is measured also by vicat needle apparatus and it gives an indicator about cement setting time that can retard of continuance of well drilling operations. final setting time is defined as the time required from start of the cement preparation until the needle cannot penetrate the cement. the cement is considered good if final setting time is about 45 minutes as a maximum limit after initial setting time [5]. 3. filtration of cement slurry filtration of cement is measured in the same way of measuring the filtration of drilling mud. the cement considers good if the filtrate volume of cement slurry which formed of water and cement with ratio equal to 0.5, is not increased more than 850 cm 3 measured with a baroid apparatus in time 30 minutes and 100 lb/in 2 pressure. in the field and for the application conditions the filter loss is acceptable with a volume of 100-150 cm 3 /30 minute in baroid apparatus. 4. free water (stability) free water is evaluated according to the ratio of displaced water from the cement slurry formed of water and cement with a weight ratio of 0.5, placed in a pipe with a volume of 250 cm 3 . the cement is considered good if the displaced water does not increase more than 1% of the total slurry volume (2.5 cm 3 ) after leaving slurry quietly for two hours under lab conditions. 5. mechanical strength of cement rock the mechanical strength of cement rock is evaluating either by compressive strength or by tensile strength and the cement consider good if cement rock has compressive strength not under 500 lb/in 2 during the first eight hours . 6. specific gravity of cement slurry the cement is considered good if the specific gravity is formed from water and cement with weight ratio 0.5, between 1.80 (112.37 lb/ft 3 ) and 1.84 (114.86 lb/ft 3 ). http://www.iasj.net/ addition of super absorbent polymer for upgrading of cement quality in iraqi oil wells www.iasj.netavailable online at: 6) 201 september( 3no. 7ijcpe vol.1 48 materials the materials used in this study are: 1. sodium polyacrylate sodium polyacrylate is known as water-lock. figure 2 shows the chemical composition of the sodium polyacrylate. it is a sodium salt of polyacrylic acid with the chemical formula [-ch2-ch (co2na) -] n. it has the ability to absorb as much as 200 to 300 times its mass in water. as you can see in figure 3, the water was fast absorbed by the sodium polyacrylate and solidified leaving no liquid behind in the cup. sodium polyacrylate is an anionic polyelectrolyte with negatively charged carboxylic groups in the main chain [4]. the material was provided from powder pack chem, product code: 9003-04-7: mumbai, india, with high purity. polyacrylate being a powder is dry blended with cement at different concentrations depending on the application. polyacrylate can also be used in neat cement (is cement mixed with water with no additives) or density slurries improve stability, fluid loss, free water, and compressive strength. fig. 2: sodium polyacrylate chemical compound [6] fig. 3: sodium polyacrylate to be mixed with water and turned into a gel 2. cement slurry cement slurry was prepared according to the cementing program in zubair field, basra, iraq. the mixing method strongly influences on slurry and set cement properties. the composition of the cement slurry formulation is shown in table 1. slurry feature the variables involved in the design of the cement slurry can be summarized in tables 2 and 3. table 1: percent of cement composition used cement materials first combination second third forth cement (gm) 270 270 270 270 silica sand (gm) 42 42 42 42 water (ml) 125 125 125 125 sodium polyacrylate (%) 0 5 10 15 table 2: standard specification of cement slurry variables unit value (min.) value (max.) density of cement slurries lb/ft 3 110 123 free water cc 2.5 2.5 initial setting time min 95 140 final setting time min 140 185 fluid loss cc/30 min 100 150 compressive strength after 8 hours psi 500 500 http://www.iasj.net/ http://en.wikipedia.org/wiki/sodium http://en.wikipedia.org/wiki/polyacrylic_acid http://en.wikipedia.org/wiki/anion http://en.wikipedia.org/wiki/polyelectrolyte http://en.wikipedia.org/wiki/carboxylic dhorgham skban ibrahim and faleh h. m. almahdawi 48 )6201september ( 3no. 17ijcpe vol. www.iasj.netonline at: available table 3: specification of tail cement slurry for zb-229 and cement slurry of present work variables unit zb229 present work density of cement slurries lb/ft 3 118.2 113.5 free water cc 2 1.35 initial setting time min na 145 final setting time min 275 190 fluid loss cc/30 min na 100 compressive strength psi 945 1708 results and discussion cement slurry must be tested before starting the cementing process. evaluation of cement slurry can be done through the following tests: 1. cement strength tests where examined the compressive strength using all sample cement prepared according to table 1 at curing time periods, 8 hours, by using pressing affixed amount 3000 psi. figure 4 shows the results after 8 hours curing time were the cement slurry where the concentration of sp 15% has a higher compressive strength which reached up to 1700 psi. figure 5 shows the models of cement with different additions of material. the figure shows the addition of 0, 5, 10, and 15% (weight percent) of sp. fig. 4: compressive strength of cement rock with different sp wt % fig. 5: models of sp addition to the cement http://www.iasj.net/ addition of super absorbent polymer for upgrading of cement quality in iraqi oil wells www.iasj.netavailable online at: 6) 201 september( 3no. 7ijcpe vol.1 44 2. density in this experiment the density increases by adding different sp wt %. figure 6 show that the highest density is 113.5 lb/ft 3 with the addition of 15 wt % of sp. generally sp addition didn’t make significant change in density of prepared cement slurry. fig. 6: shows the relationship between density and sp addition 3. shear rate and shear stress shear rate and shear stress also had been studied in this study. figure 7 shows the results of adding sp on shear rate verses shear stress. we note that the adding of sp decreases the relationship between shear stress and shear rate and in a constant ratio of change about 13%. it is highly affect the performance of slurry and water cement ratio with 15 wt % of sp to a great extent improve its strength and durability to compacted slurry reduce permeability and binding to the slurry. as concentration increase improves early compressive strength and reduces the free water; increase the viscosity of cement slurry and their packing untimely will decrease permeability. the addition of sp more than 15 wt % of sp will increase pump pressure and sometimes lead to stop circulation [7]. the filtration should be little in order not to affect the productive zones and mainly not to have high consistency for cement slurry to avoid the above mentioned problem. fig. 7: shows the relationship between shear rate and shear stress http://www.iasj.net/ dhorgham skban ibrahim and faleh h. m. almahdawi 48 )6201september ( 3no. 17ijcpe vol. www.iasj.netonline at: available 4. initial and final setting time figure 8 shows the relation between the initial and final setting time with different sp wt %. as shown in the figure the adding of sodium polyacrylate have a negative effect on initial and final setting time and the amount of change reached to the highest value of reduce between 1015% by adding. the adding of sodium polyacrylate accelerates the initial and final setting time. adding 15% of sp reduces from 187 to 145 min and from 245 to 190 for the initial and final setting time respectively. fig. 8: initial and final setting time 5. free water and filtration the cement slurry has free water equal to 3 cc without adding the sp, but after adding it the free water decrease. figure 9 shows the relation between the free water with different sp wt %. we note that adding of sp decreases the free water in a constant ratio of change about 25%. it is highly affected on the stability of slurry and water cement ratio with 15 wt % of sp which decreased by more than 50% of free water. the displaced water from the cement slurry formed was from (3-1.3 cc). fig. 9: shows the relationship between filter loss, free water with sp addition http://www.iasj.net/ addition of super absorbent polymer for upgrading of cement quality in iraqi oil wells www.iasj.netavailable online at: 6) 201 september( 3no. 7ijcpe vol.1 89 also, figure 9 shows the relation between the filter loss with different sp wt %. the cement slurry has filter loss of 185 cc without adding the sp, but after adding it the quantity decrease. we note that the adding of sp decreases the filter loss in a constant ratio of change about 20%. conclusions the use of sodium polyacrylate in cement increased the cement strength due to internal curing process. the concentration of sp 15% has increased the compressive strength from 680 to 1700 psi. the excessive amount of sodium polyacrylate used in cement has a substantial significant effect on the cement strength. sp addition didn’t make significant change in density of prepared cement slurry. specific weight of cement slurry in all the reading considered moderate type. sp was highly affected the performance of slurry and water cement ratio. sp to a great extent improve its strength and durability to compacted slurry reduce permeability and binding to the slurry. also, the adding of sodium polyacrylate accelerates the initial and final setting time. it decreases the initial and final setting time and that's considered good cement. finally, the adding of sp decreases the free water and filter loss because of his superabsorbent ability of water. it highly affect the stability of slurry and water cement ratio, but the addition of sp should not be more than 15 wt % to avoid the increase pump pressure because increase the viscosity of cement slurry and sometimes lead to stop circulation. references 1. anjuman shahriar, investigation on rheology of oil well cement slurries, 2011, doctor of philosophy thesis, the university of western ontario, london, ontario, canada. 2. d. snoeck, k. van tittelboom, n. de belie, s. steuperaert, p. dubruel, the use of superabsorbent polymers as a crack sealing and crack healing mechanism in cementitious materials,” 3rd international conference on cement repair, rehabilitation and retrofitting (iccrrr -2012), cape town, south africa, pages 152 – 157. 3. jensen, o. m., hensen f. p., waterentrained cement-based materials: ii experimental observations,” cement and concrete research, vol. 32, no. 6, june 2002, pages 973-978. 4. http://en.wikipedia.org/wiki/sodium polyacryl-ate. 5. http://www.qsarticle.com/determine -the-initial-setting-time-final-setting -time-and-consistency-of-thecement/. 6. moayyad al-nasra, optimizing the use of sodium polyacrylate in plain concrete, international journal of engineering research and applications, vol. 3, issue 3, mayjun 2013, pp.1058-1062. 7. khalil rehman memon, muhannad talib shuker, saleem qadir tunio, arshad ahmed lashari and ghulam abbass , investigating rheological properties of high performance cement system for oil wells, research journal of applied science, engineering and technology 6(20): 3865-3870, 2013. http://www.iasj.net/ http://www.qsarticle.com/determine-the-initial-setting-time-final-setting http://www.qsarticle.com/determine-the-initial-setting-time-final-setting ijcpe vol.9 no. 2 (june 2008)  iraqi journal of chemical and petroleum engineering vol.9 no.2 (june 2008) 25-41 issn: 1997-4884 optimal quantitave and distributive analysis of thermal pollution due to heated water released to rivers rafa h.al-suhaili * and tariq j.al-mosewi ** * env. eng. dept. college of engineering university of baghdad, asce member ** env. eng. dept. college of engineering university of baghdad abstract to reduce the effects of discharging heated water disposed into a river flow by a single thermal source, two parameters were changed to get the minimum effect using optimization. the first parameter is to distribute the total flow of the heated water between two disposal points (double source) instead of one and the second is to change the distance between these two points. in order to achieve the solution, a two dimensional numerical model was developed to simulate and predict the changes in temperature distribution in the river due to disposal of the heated water using these two points of disposal. matlab-7 software was used to build a program that could solve the governing partial equations of thermal pollution in rivers by using the finite difference technique. the distribution of temperature in the river was presented by using the surfer software that was used to draw the temperature contour lines and computing the areas of critical temperature (the area where the temperature exceed a certain selected value, which is believed to be critical for aquatic life). the optimum case was that which gave the minimum critical area. the decision variables are the subdivided flow of the two disposal points, and the distance between these two points. the result had indicated that the optimum case can be achieved when the flow of first point was 0.1 from the total flow of heated water and the second was 0.9 from this total flow. the optimal distance between the two points was found to be 30 m. introduction in many technological processes water is used as a cooling medium. thermal pollution occurs when heated water is discharged into rivers, lakes, oceans, or other bodies of water. the heated water raises the temperature of water above its normal level and can harm animals and plants living in water. the major waste heat producing industries are: steam electric generating plants (thermal or nuclear), petroleum refineries, steel mills, chemical plants and etc. special attention is paid to electric generating plants where cooling water are mixed with the river. steam generation of electric power plant requires rejection of tremendous quantities of waste heat typically 58% to 67% of the energy input to the plant from the generation units to the surrounding. university of baghdad college of engineering iraqi journal of chemical and petroleum engineering optimal quantitave and distributive analysis of thermal pollution due to heated water released to rivers 26 ijcpe vol.9 no. 2 (june 2008) the heated water discharged directly to the river may increase the temperature of the water approximately more than 10 °c andrzej [3]. eugene r.gilliland (1983) studied thermal pollution in soonner lake in april and found that the maximum difference in water temperature between heated and unheated area had warmed to 17 °c. in iraq many studies of thermal pollution mentioned that the difference may reach more than 10 °c especially at summer season, joody [8]. the heat discharged into a river or other moving water systems is mixed and dispersed within the receiving water; the heat is eventually transferred to the atmosphere by evaporation, radiation and/or as conduction of sensible heat. the temperature distribution downstream from the point of thermal discharge is determined by the hydrodynamic characteristics of the stream and the meteorological condition prevailing at the site. the heated water discharged directly to the river can be more dangerous to the health of the receiving water than organic pollution. higher temperature reduces solubility of oxygen and chemical reactions proceed at a faster pace masters, [10]. water temperature has an effect on the saturated oxygen value, which can be approximated as, apha, [4]: cs=14.16-0.3943t+0.007741t 2 -0.0000646t 3 (1) where: cs concentration of saturated oxygen soluble in water (mg/l) and t is the water temperature in (°c). iraqi legislations [14] do not mention allowable temperature of heated water discharge to the rivers but the minimum concentration of soluble oxygen is limited by 5 mg/l. according to eq. 1, this value required that the temperature of the river should not exceed 50 °c. national environmental health forum monographs [11] recommended that the temperature should not exceed 37 °c, in addition any change of aquatic environment due to the change in temperatures was considered as pollution and should be treated, richard[13]. from above it can be concluded that removal of waste heat prior to discharge to a body of water has became necessary. one of the treatment methods that can be used to reduce the effects of heated water discharge is to change the mode of discharge, to reduce the effects to the minimum. many studies dealt with the problem of thermal pollution in water bodies. some of these studies had presented and developed mathematical model to describe the thermal pollution in rivers. dea geun kim et. al. [6] studied the mixing of heated water which is discharged from a submerged multiport diffuser by using the three-dimensional grid-based numerical model. the laboratory experimental work has been conducted to investigate mixing characteristics of the coflowing diffuser. the following figure shows the schematic diagram of laboratory flume and experimental setup. fig. 1: dea geun kim and et.al. (2000) physical modeling apparatuses of thermal pollution. a comparison of the model simulations with the laboratory experiments results showed that the proposed model properly simulated the shapes of thermal plumes and the distributions of excess temperature. li-ren yu et. al [9] had presented unsteady state two dimensional numerical models to simulate the velocity and temperature fields in the estuary of the yangtza river in brazil. variations of bottom topography and water surface elevation were included. the distribution of velocity and temperature computed by turbulence model (k-ε) was compared with experimental results and field rafa h.al-suhaili and tariq j.al-mosewi 27 ijcpe vol.9 no. 2 (june 2008) data. it was found that the simulation using the (k-ε) model can provide more details of flow and temperature distribution than the simulation by using the model of eddy viscosity and diffusivity. cakiroglu. c and yurteri .c [5] presented mathematical models to predict the longterm effect of thermal pollution on local fish population. the fish life cycle model simulates different life stages of fish by using appropriate expressions represented by growth and mortality rates. the model was applied to a local fish species, githead (sparus aurata), for the cause of a proposed power plant in aegean region of turkey. the simulation indicated that population reduction of about 2 % to 8 % in the long run, was observed. joody, ali [8] developed one and two dimensional numerical models for simulation of the spread and mixing of thermally polluted water (single source) disposed into the river flow released from the al-doura power station starting from the outfall up to 1000 m downstream but the results showed that the effected river reach is within 150 m from the disposal point. a computer program was written by using quick basic language for computer programming. comparison of the observed data on 3 rd ,feb,2001 up to 27 th ,july,2001 with the data computed by the two dimensional model showed good agreement with a percentage error of 0.57 and 1.95 respectively. al-mosewi, tariq [1] studied the effect of the heated water released by a single source pipe from south baghdad electric power station to the tigris river; for this purpose, a two dimensional numerical model was developed to simulate and predict the temperature distribution of the heated water. momentum conservation equation and thermal energy equation were used to describe the distribution and diffusion of temperature along the river reach. furthermore the model incorporated the (k-ε) model to calculate the distribution of turbulent viscosity along this reach. fortran-77 programming language was used to write a program that solved the governing equations by using the (adi) method. the models mentioned in the above two references will be modified and developed to be used for solving doublesource of heated water that is discharged into river flows. all the equations, assumptions, initial and boundary conditions in these models will be considered in the present study. al-suhaili rafa and mohsin jasim [2] applied two dimensional numerical model for estimating temperature distribution in a river. this model was found to be sensitive to the wind speed. a laboratory physical model was built to find experimental data. the comparison of the observed results from al-doura power station and laboratory physical model with those computed by the numerical model showed a good agreement and the maximum absolute difference percentage were 16.2 %, 8.6 % respectively. governing equations and mathematical model of thermal pollution in rivers the proposed problem to be solved is shown in fig.2. the thermal pollution source flow is qo, with to temperature level. this flow is to be subdivided into two flow fractions q1 and q2, the flow of the two disposal points respectively. the disposal points are l distance apart fig. 2: thermal distribution proposed model. the determination of the transport, mixing and dilution of heated water is important for the environmental impact study. in this case, it is very important to know the governing equations concerned with the mathematical model that describes the temperature and velocity distribution in a river. the equations that will be used in this research are (rastogi and rodi [12]): 1. momentum conservation equations (navierstokes equation). 2. thermalenergy equation. 3. k-ε turbulence model. 4. density – temperature relationship of water. 5. pressure distribution. optimal quantitave and distributive analysis of thermal pollution due to heated water released to rivers 28 ijcpe vol.9 no. 2 (june 2008) eq. 1, 2 and 3 are considered as the governing differential equations, while the eq. 4 and 5 are the auxiliary equations. by expanding the above equations to directional equations in cartesian system the following can be obtained (joody [8]): horizontal momentum equation: (2) vertical momentum equation: (3) thermal-energy equation: (4) k turbulence model: (5) (6) equations 5 and 6 can be solved together with the mean flow equations to determine the two turbulence parameters and then to evaluate turbulent viscosity and diffusivity. where (7) the pressure distribution along the river depth can be presented as: (8) the two dimensional numerical model includes the above partial differential equations, which takes into account momentum, buoyancy, diffusion, density stratification and surface heat exchange. these parameters will be presented in order to obtain an algebraic equation form to be solved by numerical solution. in this research, the unsteady spread and mixing processes of heated water disposed into a river flow will be studied. the governing equations are solved numerically using the finite difference method. this model is to be completed with the optimization model presented hear after to find the optimum flow fraction between the two disposed points and the optimal distance between these two disposal points. computer program description a computer program is an essential research tool used to perform the computations of the simulation model. a computer program is written by matlab-7 that is considered as a powerful language for technical computing. the input data for the model is the length of the river, the average depth, slope of the river, roughness height, river velocity….etc. the results will be printed as temperature distribution along the study reach after the run of the following steps for the first outfall pipe: 1. reading the input data. 2. calculating the density of water river and heated water. 3. calculating the viscosity of water river and heated water.                                     222 22 z u x w z w x u g   z dzgp 0  rafa h.al-suhaili and tariq j.al-mosewi 29 ijcpe vol.9 no. 2 (june 2008) 4. reading initial condition where time equals zero for each grid point and for all variables. 5. reading boundary conditions for each grid point and for all variables. 6. calculating the pressure, density and viscosity for each grid point. 7. calculating velocity components and temperature at each grid point. 8. calculating the distribution of turbulent viscosity at each grid point. 9. return to steps from 6 to 8 after increasing time step. 10. printing temperature at each grid point after reaching the final time. the results of the temperature distribution in the river due to the double source thermal pollution will be plotted by using the surfer program to draw the temperature contour lines. the heat discharge into a river or other moving water system is mixed and dispersed within the receiving water; the equation of mixing is used to find the temperature of the mixing zone (tmix), which is an input variable required for the model. (9) where: tr=temperature of river, qr=flow of river, to=temperature of heated water, qo=flow of heated water. eventhough the model is for a double source thermal pollution, it can also be used as a single source pollution model. this can be done when the input data to the model simulate this case. this is by setting q2 and l as zero and q1=qo. the optimization model as mentioned above the aim is to find the optimal flow subdivision of the thermal source into two disposal points instead of one disposal point. these two disposal points are set at l distance apart. the objective function of the optimization model is: f(q1,q2, l)= minimum (area of critical water temperature) = minimum (area of water temperature greater than the critical temperature) = minimum (at > tc) subject to the following constraints: q1 ≤ qo q2 ≤ qo q1+ q2= qo t1= t2= to for the case of the double disposal point the mixing eq. (9) could be modified by substituting q1 and/or q2 instead of qo. the optimum solution could be found by computing the temperature distribution using the numerical model, and hence, the area of critical temperature for different sets of input values of the decision variables q1, q2 and l that satisfies the constraints. results and discussion fig. 3 shows the temperature distribution along the river due to a single source thermal pollution, i.e. q1=qo , q2=0, l=0. this case was selected to allow for comparison with the cases of double source thermal pollution with different flow subdivision and different distance between the two thermal source pollution disposal points. table 1 thermal polluted area for different critical temperature value of the single source pollution,q1=qo=2 m 3 /sec, tr=35 ºc,to=48 ºc,q2=0,l=0, u=2 m/sec, qr=5 m 3 /sec, time=100 sec temperature critical tc (ºc) 39 38 37 thermal polluted area at (m 2 ) 57 83 59 total area (m 2 ) 199 as mentioned before, the reduction of the effected areas (high temperature area) to the minimum value will be done by changing two parameters; the first is the division of the original heated water flow between two disposal points instead of one, and the second by changing the length between these two points. these parameters will be optimized to get the optimum decision. before that the numerical model should be modified to describe the temperature distribution with two outfall pipes. the reduction of the high temperature area will be helpful in the reduction of the soluble oxygen depletion area. the mathematical model will be applied on two disposal points instead of one. in other words the computer program will be applied for two points and this requires considering the data of the first disposal point result of step 10 of the computer program as an input data for the second outfall (disposal point), then repeating steps 1 to 10 of the computer program to compute the temperature distribution for the case of two disposal points. optimal quantitave and distributive analysis of thermal pollution due to heated water released to rivers 30 ijcpe vol.9 no. 2 (june 2008) the total flow of the heated water will be subdivided between these two disposal points with increments from 0.1 to 0.9 fractions. in addition the distance between these two points (l) will be selected as 10 m, 20 m, and 30 m. to study the effect of distance between the two disposal points the distance must begin with 10 m or more. the reason of choosing the lowest length of 10 m was arised from the fact gained from the application of the mathematical model, that within a distance less than 10 m little variation in temperature distribution was found due to the single source point. fig. 4 to 12, show the temperature distribution within the river reach resulting from different fraction divisions of the heated water flow between the two disposal points for a distance of (10 m) between them. where q1 is the flow of the first disposal point and q2 is the flow of the second one, the total flow of the two pipes is qo as mentioned before, tr=35 ºc, qo=2 m 3 /sec=q1+q2 , and time to reach these conditions=100 sec. table 2 shows the area of thermal pollution for three different critical temperatures 39, 38 and 37 °c calculated using the contours shown in the above figures; the cells that have minimum area value are shaded. table 2 area of critical temperature for different flow subdivisions and 10m distance between the two disposal points. the above table shows that the area of critical temperature 39 °c contour line varied from 16.3 to 1.54 m 2 in which the minimum area occured at q1=0.1qo and q2=0.9qo while the minimum area of temperature 38 °c contour line was 12.4 m 2 at q1=0.2qo and q2=0.8qo, in addition the minimum area of temperature 37 °c was at q1=0.1qo and q2=0.9qo. so that it became obvious that the optimum case is obtained at q1=0.1qo and q2=0.9qo that gave he minimum critical area. figures (13, to 21) show the temperature distribution within the river reach resulting from different fraction divisions of the heated water flow between the two disposal points for distance of (20 m) between them. table 3 shows the area for three different critical temperatures 39,38 and 37 °c calculated using the contours shown in the above figures, the cells that have minimum area value are shaded. it can be concluded from table 3 that the minimum critical area will be at q1=0.1qo and q2=0.9, this may be due to the reason that the water river will retain its normal temperature before reaching to the second disposal point. table 3 area of critical temperature for different flow subdivisions and 20m distance between the two disposal points. figures (22, to 30) show the temperature distribution within the river reach resulted from different fraction divisions of the heated water flow between the two disposal points for distance of (30 m) between them. table 4 shows the area for three different critical temperatures 39,38 and 37 °c calculated using the contours shown in the above figures, the cells that have minimum area value are shaded. table 4 area of critical temperature for different flow subdivisions and 30m distance between the two disposal points. l=10 m flow increments occupied area for each contour total area 39 °c 38 °c 37 °c q1= 0.9, q2= 0.1 16.3 117.7 62.5 196.5 q1= 0.8, q2= 0.2 10.2 114.5 68.3 193 q1= 0.7, q2= 0.3 8.2 102 86 188 q1= 0.6, q2= 0.4 6.8 52.2 122.5 181.5 q1= 0.5, q2= 0.5 5.6 33.3 132.7 171.6 q1= 0.4, q2= 0.6 4.5 24.5 126.8 155.8 q1= 0.3, q2= 0.7 3.4 19.9 66.9 90.2 q1= 0.2, q2= 0.8 2.4 12.4 51 63.4 q1= 0.1, q2= 0.9 1.54 13.3 34.8 48.1 l=20 m flow increments occupied area for each contour total area 39 °c 38 °c 37 °c q1= 0.9, q2= 0.1 7.3 123.7 70 201 q1= 0.8, q2= 0.2 6.38 113.2 77 197 q1= 0.7, q2= 0.3 5.8 95.2 90 191 q1= 0.6, q2= 0.4 5.24 46 131.6 183 q1= 0.5, q2= 0.5 4.6 30.2 140.2 175 q1= 0.4, q2= 0.6 3.8 23.5 127.5 151 q1= 0.3, q2= 0.7 3 19.3 62.8 85.1 q1= 0.2, q2= 0.8 2.2 16 43.6 61.7 q1= 0.1, q2= 0.9 1.45 13.1 33 47.5 l=30 m flow increments occupied area for each contour total area 39 °c 38 °c 37 °c q1= 0.9, q2= 0.1 0 118 85 203 q1= 0.8, q2= 0.2 0.9 101 95 197 q1= 0.7, q2= 0.3 1.8 52.2 136 190 q1= 0.6, q2= 0.4 2.4 32.8 143.8 179 q1= 0.5, q2= 0.5 2.5 25.3 136 164 q1= 0.4, q2= 0.6 2.4 21.1 88.5 112 q1= 0.3, q2= 0.7 2.1 18 55 75 q1= 0.2, q2= 0.8 1.73 15.3 41 58 q1= 0.1, q2= 0.9 1.3 12.7 32 46 rafa h.al-suhaili and tariq j.al-mosewi 31 ijcpe vol.9 no. 2 (june 2008) the above table shows that the area occupied by 39 c contour line varies from 0 to 2.5 m 2 and these values are considered small but the minimum area occupied by 38 and 37 c contours lines are 12.7 and 32 m 2 respectively, so these values of occupied areas will assign the optimum associated decision variables qo, q1 for l=30 m. from the above figures and tables it could be concluded that the optimum solution to reduce the effects of heated water discharge into rivers by the division of the heated water flow into two disposal points, the first one has 0.1 from total flow and the second has 0.9 from total flow and the distance between these two pipes of 30 m. for winter season the average river water temperature could reach 20 °c and the temperature of heated water reach to 30 °c. so another difference of temperature data was used as input data for mathematical model, the following tables show the occupied area for water river temperature where the total affected area case of single outfall disposal point was equal to 228 m 2 . table 5 area of critical temperature for different flow subdivisions and 10m distance between the two disposal points. table 6 area of critical temperature for different flow subdivisions and 20m distance between the two disposal points. table 7 area of critical temperature for different flow subdivisions and 30m distance between the two disposal points. form the above tables the optimum case that gave the minimum area affected was still at distance 30 m between disposal points where flow of first point was equal to 0.1 from total flow and the second was 0.9 from the total flow. l=10 m flow increments occupied area for each contour total area 22 °c 21 °c q1= 0.9, q2= 0.1 134 93 227 q1= 0.8, q2= 0.2 124 101 225 q1= 0.7, q2= 0.3 109 113 222 q1= 0.6, q2= 0.4 56 161 217 q1= 0.5, q2= 0.5 33.8 177.8 211.6 q1= 0.4, q2= 0.6 26.6 175.4 202 q1= 0.3, q2= 0.7 22 171 193 q1= 0.2, q2= 0.8 17.5 107 124.7 q1= 0.1, q2= 0.9 14 68.4 82.4 l=20 m flow increments occupied area for each contour total area 22 °c 21 °c q1= 0.9, q2= 0.1 133 102 235 q1= 0.8, q2= 0.2 122 110 232 q1= 0.7, q2= 0.3 103 125 228 q1= 0.6, q2= 0.4 82.5 148.5 231 q1= 0.5, q2= 0.5 31.6 184 215.8 q1= 0.4, q2= 0.6 25.7 179.3 205 q1= 0.3, q2= 0.7 21 167.5 188.5 q1= 0.2, q2= 0.8 17 104 121 q1= 0.1, q2= 0.9 13.8 67.8 81.6 l=30 m flow increments occupied area for each contour total area 22 °c 21 °c q1= 0.9,q2= 0.1 120.7 120 241 q1= 0.8,q2= 0.2 105 132 237 q1= 0.7,q2= 0.3 55.5 177.5 233 q1= 0.6,q2= 0.4 32 194 226 q1= 0.5,q2= 0.5 26 191 217 q1= 0.4,q2= 0.6 22.3 181.5 203.8 q1= 0.3,q2= 0.7 18.9 161 180 q1= 0.2,q2= 0.8 16 94.6 110.6 q1= 0.1,q2= 0.9 13.3 65.7 79 rafa h.al-suhaili and tariq j.al-mosewi 33 ijcpe vol.9 no. 2 (june 2008) 0 1 2 3 4 d e p th o f r ive r (m ) 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 r iv e r r e a c h (m ) 3 5 c 3 6 c 3 7 c 3 8 c 3 9 c fig. 3: temperature distribution from a single source where tr=35 ºc and tmix=39.3 ºc. . 0 1 2 3 4 d e p th o f r ive r (m ) 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 r iv e r r e a c h (m ) 3 5 c 3 6 c 3 7 c 3 8 c 3 9 c fig. 4: temperature distribution where q1=0.9qo,q2=0.1qo. 0 1 2 3 4 d e p th o f r ive r (m ) 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 r iv e r r e a c h (m ) 3 5 c 3 6 c 3 7 c 3 8 c 3 9 c fig. 5: temperature distribution where q1=0.8qo,q2=0.2qo. 0.2 qo 0.8 qo depth of river 0.1 qo 0.9 qo depth of river qo=2 m 3 /sec depth of river optimal quantitave and distributive analysis of thermal pollution due to heated water released to rivers 34 0 1 2 3 4 d e p th o f r ive r 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 r iv e r r e a c h 3 5 c 3 6 c 3 7 c 3 8 c 3 9 c fig. 6: temperature distribution where q1=0.7qo,q2=0.3qo. 0 1 2 3 4 d e p th o f r ive r 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 r iv e r r e a c h 3 5 c 3 6 c 3 7 c 3 8 c 3 9 c fig. 7: temperature distribution where q1=0.6qo,q2=0.4qo. 0 1 2 3 4 d e p th o f r ive r (m ) 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 r iv e r re a c h (m ) 3 5 c 3 6 c 3 7 c 3 8 c 3 9 c fig. 8: temperature distribution where q1=0.5qo,q2=0.5qo. 0 1 2 3 4 d e p th o f r ive r (m ) 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 r iv e r r e a c h (m ) 3 5 c 3 6 c 3 7 c 3 8 c 3 9 c fig. 9:temperature distribution where q1=0.4qo,q2=0.6qo. depth of river 0.6 qo 0.4 qo depth of river 0.5 qo 0.5 qo 0.6 qo 0.4qo depth of river 0.7 qo 0.3 qo depth of river rafa h.al-suhaili and tariq j.al-mosewi 35 ijcpe vol.9 no. 2 (june 2008) 0 1 2 3 4 d e p th o f r ive r (m ) 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 r iv e r r e a c h (m ) 3 5 c 3 6 c 3 7 c 3 8 c 3 9 c fig. 10: temperature distribution where q1=0.3qo,q2=0.7qo. 0 1 2 3 4 d e p th o f r ive r (m ) 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 r iv e r r e a c h (m ) 3 5 c 3 6 c 3 7 c 3 8 c 3 9 c fig. 11: temperature distribution where q1=0.2qo,q2=0.8qo. 0 1 2 3 4 d e p th o f r ive r (m ) 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 r iv e r r e a c h (m ) 3 5 c 3 6 c 3 7 c 3 8 c 3 9 c fig.12: temperature distribution where q1=0.1qo,q2=0.9qo. 0 1 2 3 4 d e p th o f r ive r (m ) 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 r iv e r r e a c h (m ) 3 5 c 3 6 c 3 7 c 3 8 c 3 9 c fig. 13: temperature distribution where q1=0.9qo,q2=0.1qo. 0.7 qo 0.3 qo depth of river 0.8 qo 0.2 qo depth of river 0.9 qo 0.1 qo depth of river 0.1 qo 0.9 qo depth of river 0.2 qo 0.8 qo depth of river optimal quantitave and distributive analysis of thermal pollution due to heated water released to rivers 36 0 1 2 3 4 d e o th o f r ive r (m ) 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 r iv e r r e a c h (m ) 3 5 c 3 6 c 3 7 c 3 8 c 3 9 c fig. 14: temperature distribution where q1=0.8qo,q2=0.2qo. 0 1 2 3 4 d epth of r iver (m ) 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 r iv e r r e a c h (m ) 3 5 c 3 6 c 3 7 c 3 8 c 3 9 c fig. 15: temperature distribution where q1=0.7qo,q2=0.3qo. 0 1 2 3 4 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 3 4 c 3 5 c 3 6 c 3 7 c 3 8 c 3 9 c fig. 16: temperature distribution where q1=0.6qo,q2=0.4qo. 0 1 2 3 4 d epth of r iver (m ) 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 r iv e r r e a c h (m ) 3 5 c 3 6 c 3 7 c 3 8 c 3 9 c fig. 17: temperature distribution where q1=0.5qo,q2=0.5qo. 0.4 qo 0.6 qo depth of river 0.3 qo 0.7 qo depth of river 0.5 qo 0.5 qo depth of river rafa h.al-suhaili and tariq j.al-mosewi 37 ijcpe vol.9 no. 2 (june 2008) 0 1 2 3 4 d e p th o f r ive r (m ) 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 r iv e r r e a c h (m ) 3 5 c 3 6 c 3 7 c 3 8 c 3 9 c fig. 18: temperature distribution where q1=0.4qo,q2=0.6qo. 0 1 2 3 4 d e p th o f r ive r (m ) 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 r iv e r r e a c h (m ) 3 5 c 3 6 c 3 7 c 3 8 c 3 9 c fig. 19: temperature distribution where q1=0.3qo,q2=0.7qo. 0 1 2 3 4 d e p th o f r ive r (m ) 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 r iv e r r e a c h (m ) 3 5 c 3 6 c 3 7 c 3 8 c 3 9 c fig. 20: temperature distribution where q1=0.2qo,q2=0.8qo. 0 1 2 3 4 d e p th o f r ive r (m ) 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 r iv e r r e a c h (m ) 3 5 c 3 6 c 3 7 c 3 8 c 3 9 c fig. 21: temperature distribution where q1=0.1qo,q2=0.9qo. 0.7 qo 0.3 qo depth of river 0.6 qo 0.4 qo depth of river 0.8 qo 0.2 qo depth of river 0.9 qo 0.1 qo depth of river optimal quantitave and distributive analysis of thermal pollution due to heated water released to rivers 38 0 1 2 3 4 d e p th o f r ive r (m ) 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 r iv e r r e a c h (m ) 3 5 c 3 6 c 3 7 c 3 8 c 3 9 c fig. 22: temperature distribution where q1=0.9qo,q2=0.1qo. 0 1 2 3 4 d epth of r iver (m ) 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 d e p th o f r iv e r (m ) 3 5 c 3 6 c 3 7 c 3 8 c 3 9 c fig. 23: temperature distribution where q1=0.8qo,q2=0.2qo. 0 1 2 3 4 d epth of r iver (m ) 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 r iv e r r e a c h (m ) 3 5 c 3 6 c 3 7 c 3 8 c 3 9 c fig. 24: temperature distribution where q1=0.7qo,q2=0.3qo. 0 1 2 3 4 d e p th o f r ive r (m ) 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 r iv e r r e a c h (m ) 3 5 c 3 6 c 3 7 c 3 8 c 3 9 c fig. 25: temperature distribution where q1=0.6qo,q2=0.4qo. 0.1 qo 0.9 qo depth of river 0.2 qo 0.8 qo depth of river 0.3 qo 0.7 qo depth of river 0.4 qo 0.6 qo depth of river rafa h.al-suhaili and tariq j.al-mosewi 39 ijcpe vol.9 no. 2 (june 2008) 0 1 2 3 4 d epth of r iver (m ) 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 r iv e r r e a c h (m ) 3 5 c 3 6 c 3 7 c 3 8 c 3 9 c fig. 26: temperature distribution where q1=0.5qo,q2=0.5qo. 0 1 2 3 4 d epth of r iver (m ) 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 r iv e r r e a c h (m ) 3 5 c 3 6 c 3 7 c 3 8 c 3 9 c fig. 27: temperature distribution where q1=0.4qo,q2=0.6qo. 0 1 2 3 4 d e p th o f r ive r (m ) 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 r iv e r r e a c h (m ) 3 5 c 3 6 c 3 7 c 3 8 c 3 9 c fig. 28: temperature distribution where q1=0.3qo,q2=0.7qo. 0 1 2 3 4 d e p th o f r ive r (m ) 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 r iv e r r e a c h (m ) 3 5 c 3 6 c 3 7 c 3 8 c 3 9 c fig. 29: temperature distribution where q1=0.2qo,q2=0.8qo. 0.5 qo 0.5 qo depth of river 0.6 qo 0.4 qo depth of river 0.7 qo 0.3 qo depth of river 0.8 qo 0.2 qo depth of river optimal quantitave and distributive analysis of thermal pollution due to heated water released to rivers 40 0 1 2 3 4 d e p th o f r ive r (m ) 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 r iv e r r e a c h (m ) 3 5 c 3 6 c 3 7 c 3 8 c 3 9 c fig. 30: temperature distribution where q1=0.1qo,q2=0.9qo. conclusions 1. the optimum case to reduce the effects of heated water discharge released from various plants can be obtained by the division of the flow of the heated water by two disposal points instead of one, the first one discharges 0.1 from total flow and the second 0.9 from total flow of heated water in which the distance between them is be equal to or exceeds 30 m, this procedure gave reduction in total effected area approximately 77 % with single point. 2. if the discharge of heated water is equal to or less than 20% from total river flow then the maximum spreading of the thermal pollution plume will not exceed 100 m from the outfall location and after this distance the difference between heated and unheated water does not exceed 2 °c. nomenclature cs : concentration of saturated dissolved oxygen mg/l c1,c2: constants g : gravitational acceleration m/s 2 k : turbulence kinetic energy m 2 /s 2 l : distance between two pipes m p : pressure n/m 2 q o : total heated water discharge m 3 /s q1,q2: flow of first and second points respectively m 3 /s qr : flow of river m 3 /s t : temperature ο c tmix,tr: temperature of mixing zone and river ο c u : velocity in x-direction m/s v : velocity in y-direction m/s w : velocity in z-direction m/s α : heat transfer coefficient w/(m 2 .k) ρ : density kg/m 3 σ : prandtle number µ : viscosity n.s/m 2 ε : dissipation rate of turbulent kinetic energy m 2 /s 3 reference 1. al-mosewi, tariq, (2002),”studying of heated water released from south-baghdad electric power station to the tigris river”,m.sc. thesis .university of technology. 2. al-suhaili rafa and mohsin jasim,(2006),”twodimensional numerical model for thermal pollution of single source in river”, journal of engineering. university of baghdad,no.1,vol.12.pp.25-29. 3. andrzej pozlewicz,(2005)” modelling of thermal pollution dispersion in lower odra river”. department of geotechnical engineering, szczecin university of technology, poland,pdf,internet. 4. apha,american public health association,(1975),”standard methods for the examination of water and wastewater”. washington,d.c. 0.9 qo 0.1 qo depth of river rafa h.al-suhaili and tariq j.al-mosewi 41 ijcpe vol.9 no. 2 (june 2008) 5. cakiroglu,c., and yurteri,c.,(1998),”methodology for predicting cooling water effects on fish”.journal.env.eng.,vol.124,no.7. 6. dae geun kim,(2000),” modeling the mixing of heated water discharged from a submerged multiport diffuser”,journal of hydraulic research,vol.3,no.4,internet . 7. eugene r.gilliland,(1983)” density and distribution of larval fish in an oklahoma power plant cooling water reservoir”. department of zoology, oklahoma state university, stillwater, oklahoma,pdf,internet. 8. joody ali.s.,(2001)” studying of thermal pollution of the heated water released from aldoura power station” m.sc.thesis, college of engineering, university of al-mustansiria. 9. li ren yu and righetto a.m,(1998),”tideland transport modeling using turbulelance k-ε model”. journal.hyd.div,vol.124,no.3. 10. masters .g.m,(1998),”introduction to environmental engineering and science”,2 nd .edition.usa. 11. national environmental health forum monographs ,water series no.2.(1996), “guidance on water quality for heated spas”,printed by open book publisher.internet. 12. rastogi, a.k. and rodi ,w.,(1978),” prediction of heat and mass transfer in open channel”.journal.hyd.div.vol.104,no.3. 13. richard,n.l.,(2001),”thermal pollution”. university of north caroline,pdf,internet. دائزة االعالم والتىعيت البيئيت / وسارة البيئت .14 نظبم / 1990النبفذة لعبم التشزيعبث البيئيت العزاقيت ", 25رقن صيبنت االنهبر والويبه العوىهيت هن – 1967لسنت ".التلىث ijcpe vol.5 no. 3 (2007) iraqi journal of chemical and petroleum engineering vol.10 no.3 (september 2009) 57-63 issn: 1997-4884 methanol effect on color stability and shelf life of phenolic resin compound under acidic conditions ammar waadallah ahmed * * bio chemical engineering department – al khwarizmi college of engineeringuniversity of baghdad – iraq abstract the object of this work is to investigate the effect of the addition of methanol on the shelf life and color characteristics of novolak resin. different percentages were added and two mechanisms were suggested for the addition. high ortho structure (1, 2-3) novolak resin was prepared and used in the above investigation. experimental determination using ft-ir and uv-spectroscopy showed that on the addition of 30% of methanol and according to the second mechanism of addition novolak shelf life increased to 12 months without obvious decomposition and color change. it is suggested that methanol plays an important role in the inhabitation of the reactive sites on the resi n that are responsible for the oxidation of the polymer when exposed to atmospheric or storage conditions. introduction phenol, formaldehyde resin is considered to be one of the most important polymers in the molding industry. the first commercially available resin is indeed phenol formaldehyde resin developed by leo m. backland in 1907 based on earlier discovery by a. von bayer in 1872. phenolic resins (high ortho figure (1)) are produced by the reaction of formaldehyde with excess phenol under acidic condition (ph = 1 to 3) with typical formaldehyde to phenol ratios are between 0.8 and 0.85. the most common industrial catalysts are oxalic, hydrochloric, sulfuric, phosphoric, and sulfuric acids. fig. 1 random and high ortho novolak structures university of baghdad college of engineering iraqi journal of chemical and petroleum engineering methanol effect on color stability and shelf life of phenolic resin compound under acidic conditions 58 vol.10 no.3 (september 2009) color change before(20) use this resin in molding to produce any composite material some properties were changed during storage starting from oxidation to color instability which affect the final composite properties the main reason for color change of novolak is the existence of un-reacted phenol that is not removed completely from final product that undergoes decomposition reaction (20, 21, and 22). this compound is considered responsible for the color change from colorless to reddish. the above compound known as quinones root (1, 5, and 22), attacks the polymer chain and causes decomposition by breaking the polymeric chain at these sites. the following mechanism of attack is proposed: it is also possible that uneven distribution of reactive site on the polymer may lead to oxidation and consequent decomposition of the final polymer structure. modified resins polymers are considered to be photo-resistant and stable, if they resist the influence of oxidation in an inert atmosphere without changing in their properties significantly. the following methods are suitable to improve the oxidative resistance of phenolic resins [1] 1. etherification or estrification of phenolic hydroxyl group. 2. complex formation with polyvalent elements (ca, mg,zn,cd,…). 3. replacement of the methylene linking group by heteroatoms (o,s,n,si,…). the most important general modification reactions in phenolic polymer chemistry are the etherification and calkylation (friedel-crafts) reaction (1). both reactions are commonly used to enhance flexibility and compatibility with polymers and solvent to reactivity and performance. etherification reaction the hydroxymethyl group in phenol prepolymers can easily be etherified (a) with alcohol because of their tendency to form hydroxybenzylcarbonium ions. high hudroxymethylated phenols and an excess of alcohol are used to avoid the self-condensation reaction. in general the reaction is performed with monoalcohols like methanol, butanol and isobutanol. on the other hand, the etherification of the phenolic hydroxyl group (o-alkylation (b)) leads to improved alkali resistance. better flexibility, light fastness and with allyl compounds, enhanced air drying properties are also obtained. experimental work the reaction of phenol with formaldehyde in acid medium proceeds as follows: 2c6h5oh + ch2 o c6h4ohch2 c6h4oh + h2o novolak was prepared by reacting formaldehyde with excess phenol under acidic conditions; hydrochloric acid was used as a catalyst. the reaction was carried out in stainless steel batch reactor as shown in figure (2). high ortho novolak resin was prepared using the following well known ratios (2, 3): f/p = 0.8, a/p = 0.01 and w/f = 2..5577 or oh . o o . environment effect ammar waadallah ahmed 59 vol.10 no.3 (september 2009) fig. 2 equipments used in the production of novolak resin the reaction was carried out for about 4 hours at an operating temperature of 80oc and ph of 1.5 in a 3 liter stainless steel jacketed reactor. a provision was made for mechanical stirrers to be immersed into the reactor. other previous were made for a condenser, reactant input, and temperature and pressure control instrument. products are withdrawn from the bottom of the reactor. different percentages of methanol added and two mechanisms were suggested for the addition .methanol ratio was added according to formaldehyde concentration. first mechanism of addition reactants were added to the reactor according to the molar ratio mentioned earlier (2, 3) and then methanol (20% of the total amount of reactants at 20oc) was added to the reactants at a mixing speed of 500 rpm then, the temperature was raised up to 80oc gradually. reaction was continued for about 4 hours and novolak resin was formed. heating was halted and two layers were observed. i.e. water at the top of the novolak was formed. in order to get rid of the water formed as a by-product, the reactor was heated up to 120oc for 2 hours with mixing under 0.1 bar vacuum. to remove about 90% of the formed water. second mechanism of addition the same procedure above was carried out; however, methanol was added after completion of polymerization i.e. when the two layers of by-product and novolak were formed. then the mixing and vacuum process was continued until about 90% of the residual water was removed. the same procedure was carried out several times using different percentage of methanol in order to determine the optimum value. the following ratios were suggested (15, 30, 45 and 60%) based on total volume. electronic spectrophotometer measurements were conducted by schimadzu uv-214 a (uv-visible spectrophotometer) using mek (methyl ethyl keton) as a solvent and a quartz cell of 1.0 cm path length. samples for that purpose were prepared as shown in table (1). a comparison was made between samples with methanol added against this with no methanol added using ft-ir. table (1): design parameter for the experimental work rruunn nnoo.. mmiixxttuurree vvoolluummee mmll.. mmeetthhaannooll vvoolluummee mmll.. ttoottaall vvoolluummee mmll.. ppeerrcceennttaaggee ooff mmeetthhaannooll %% 11 6600 00 6600 00%% 22 6600 1100..66 7700..66 1155%% 33 6600 2255..77 8855..77 3300%% 44 6600 4499 110099 4455%% 55 6600 9900 115500 6600%% results and discussion ssaammpplleess were left for a period of about 12 month under ordinary storage at atmospheric conditions and monthly tests were carried out using uv-spectroscopy and finally ft-ir instruments. color change was observed by naked eye. the following results are obtained and showed in the table (2). short shelf life and color change were observed for samples that were not treated with methanol. a decomposition of its structure is expected due to activity of reactive sites. methanol was suggested as an additive for two main reasons. 1. its structural composition is similar to that of formaldehyde. 2. cheap and readily available. according to the experimental results the second mechanism of addition was in favor of the first i.e. addition of methanol is suggested to be added after the polymerization step of water mixing and vacuum application for water withdrawal. it could be seen that sample (3) at 30% methanol did not suffer structural and no color change, as shown in table (2) and figure (3). methanol effect on color stability and shelf life of phenolic resin compound under acidic conditions 60 vol.10 no.3 (september 2009) first month: all samples absorbed the light at (λ = 343 nm) with no color change as shown in data table (2). second to 12th month: first sample changed into reddish brown color with (λ = 363 nm ±5) as shown in table (2). third to 12th month: all samples showed decomposition and color change except sample (3) with 30% methanol addition as shown in table (2). the value of λ was 345 nm ±2 during the above periods. the effect of methanol addition on the polymer can be explained as follows: assists in the withdrawal of by-product water formed in reaction which considered being a physical process (16, 17, 18, and 22). inhibit reactive sites of –ch2 groups i.e. that exist on the high ortho novolak which is considered to be a chemical process (11, 16, 17, and 19). the effect of methanol addition on the un-reacted chemical can be explained as follows: 1. complete the phenol – formaldehyde reaction and obtain further novolak which is a chemical process (11, 19, and 20). 2. get ride of un-reacted phenol from reaction mixture which is considered responsible for the decomposition of novolak structure during storage and hence reducing the shelf life (10, 11, 12, and 15). ft-ir test made for samples (1) and (3) indicated the fact that methanol addition according to the second mechanism was of physical meaning and was not chemically oriented since no structural changes were observed as shown in figures (4, 5 and 6). fig.3 the change in color for sample (1) and (3) after 12 month of novolak resin table (2): uv-visible results for each sample with the methanol percentage deferent during 12 month ssaammpplleess mmoonntthh ppeerriioodd mmeetthhaannooll %% λλ ccoolloorr cchhaannggee 11 11 00 334433 nnoo cchhaannggee 22 11 1155 334433 nnoo cchhaannggee 33 11 3300 334433 nnoo cchhaannggee 44 11 4455 334433 nnoo cchhaannggee 55 11 6600 334433 nnoo cchhaannggee ssaammpplleess mmoonntthh ppeerriioodd mmeetthhaannooll %% λλ ccoolloorr cchhaannggee 11 22 00 334433 cchhaannggee 22 22 1155 334433 nnoo cchhaannggee 33 22 3300 334433 nnoo cchhaannggee 44 22 4455 334433 nnoo cchhaannggee 55 22 6600 334433 nnoo cchhaannggee ssaammpplleess mmoonntthh ppeerriioodd mmeetthhaannooll %% λλ ccoolloorr cchhaannggee 11 33 00 334433 cchhaannggee 22 33 1155 334433 cchhaannggee 33 33 3300 334433 nnoo cchhaannggee 44 33 4455 334433 cchhaannggee 55 33 6600 334433 cchhaannggee ssaammpplleess mmoonntthh ppeerriioodd mmeetthhaannooll %% λλ ccoolloorr cchhaannggee 11 1122 00 334433 ssttrroonngg cchhaannggee 22 1122 1155 334433 ssttrroonngg cchhaannggee 33 1122 3300 334433 nnoo cchhaannggee 44 1122 4455 334433 ssttrroonngg cchhaannggee 55 1122 6600 334433 ssttrroonngg cchhaannggee ammar waadallah ahmed 61 vol.10 no.3 (september 2009) ffiigg..44fftt--iirr ssttaannddaarrdd pplloott ooff oorrtthhoo nnoovvoollaakk rreessiinn wwiitthhoouutt ddeeccoommppoossiittiioonn ffiigg..55 fftt--iirr pplloott ooff oorrtthhoo nnoovvoollaakk rreessiinn wwiitthhoouutt mmeetthhaannooll aaddddiittiioonn ssaammppllee ((11)).. methanol effect on color stability and shelf life of phenolic resin compound under acidic conditions 62 vol.10 no.3 (september 2009) ffiigg..66 fftt--iirr pplloott ooff oorrtthhoo nnoovvoollaakk rreessiinn wwiitthh mmeetthhaannooll aaddddiittiioonn ssaammppllee ((33)).. conclusions 1. experimental determination using ft-ir and uvspectroscopy showed that on the addition of 30% of methanol and according to the second mechanism of addition, lead to the increase of shelf life to 12 months without obvious decomposition and color change. 2. it is suggested that methanol plays an important role in the inhabitation of the reactive sites on the resin which are responsible for the oxidation of the polymer when exposed to atmospheric or storage condition. nomenclature a moles of catalyst f moles of formaldehyde p moles of phenol w moles of water λ absorbed light of uv-spectroscope references 11.. knopf a. and scheib w. (1979) chemistry and application of phenolic resins, springer – verlag publishing com., ny. 22.. van oss j.f. (1973), journal of material and technology, vol. 6, 586. 33.. kirk – othmer (1984), encyclopedia of chemical technology, vol. 10, 335, john wiley & sons, inc. 44.. francis a., carey (1996), organic chemistry, mcgraw-hill companies, third edition. 55.. kirk – othmer (1984) “encyclopedia of chemical technology” vol. 17, 384, john wiley & sons, inc.. 66.. linjie zhi, tong zhao (2003) preparation of phenolic resin/silver nanocomposites via in-situ reduction, chinese chemical letters vol. 14, no. 4, pp 426 – 428. 77.. leite, j. l.; pires, a. t. n.; souza, s. m. a. g. ulson de (april june 2004) characterization of a phenolic resin and sugar cane pulp composite, brazilian journal of chemical engineering, vol. 21, no. 02 pp. 253 – 260. http://www.scielo.br/cgi-bin/wxis.exe/iah/?isisscript=iah/iah.xis&base=article%5edlibrary&format=iso.pft&lang=i&nextaction=lnk&indexsearch=au&exprsearch=leite,+j.+l. http://www.scielo.br/cgi-bin/wxis.exe/iah/?isisscript=iah/iah.xis&base=article%5edlibrary&format=iso.pft&lang=i&nextaction=lnk&indexsearch=au&exprsearch=pires,+a.+t.+n. http://www.scielo.br/cgi-bin/wxis.exe/iah/?isisscript=iah/iah.xis&base=article%5edlibrary&format=iso.pft&lang=i&nextaction=lnk&indexsearch=au&exprsearch=souza,+s.+m.+a.+g.+ulson+de http://www.scielo.br/cgi-bin/wxis.exe/iah/?isisscript=iah/iah.xis&base=article%5edlibrary&format=iso.pft&lang=i&nextaction=lnk&indexsearch=au&exprsearch=souza,+s.+m.+a.+g.+ulson+de ammar waadallah ahmed 63 vol.10 no.3 (september 2009) 88.. e. fossum and k. matyjaszewski, (1997), morphology of polystyrene-block-poly (methylphenylsilylene). journal of macromolecules, 30 (6), pp 1765–1767. 99.. julia a. king, michael d. via, jason m. keith (2009), effects of carbon fillers on rheology of polypropylene-based resins. journal of composite materials, vol. 43. 1100.. h. liu, x. ge, y. ni, q. ye, z. zhang, (2001), preparation and characterization of zns / poly (acrylamide-co-acrylic acid) dendritical nanocomposites by γ-irradiation. radiat. phys. chem, 61, 89. 1111.. d. kumlutas and i. h. tavman, (2006), a numerical and experimental study on thermal conductivity of particle filled polymer composites. journal of thermoplastic composite materials, 19(4): 441 455. 1122.. chin-lung chiang, chen-chim. ma,1 dai-lin wu,1 hsu-chiang kuani, (2008), preparation, characterization, and properties of novolactype phenolic/sio2 hybrid organic–inorganic nanocomposite materials by sol–gel method, journal of frontiers of chemical engineering in china, volume 2, number 3. 1133.. d. mangaiyarkarsai, k. kamada, n. saito, s. ichikawa, t. akai, k. kadono and t. yazawa, (2005), large area multi-color changes induced by femtosecond laser pulses in soda-lime silicate glass embedded with ag nanoparticles. journal of noncrystalline solids, volume 351, pages 3156-3159. 1144.. john j. stolfo (nov. 6, 1979) production of novel modified novolak resin and there use in pressure sensitive papers, united state patent (4,173,684). 1155.. maynard h. olson, john c. chang, imelda a. muggli (apr. 18, 1989) process for providing polyamide materials with stain resistance with sulfonated novolak resin and polymethacrylic acd, united state patent (4,822,373). 1166.. medhat a. toukhy, leo klawansky (mar. 22, 1983) positive novolak photo resist compositions, united state patent (4,377,631). 1177.. kazuto kunita (may 21, 2002) photosensitive resin composition image recording material and planographic printing plate using the same, united state patent (6,391,519). 1188.. zoilo cheng ho tan (aug. 22, 2000) photoresist developer and method, united state patent (6,107,009). 1199.. yoshiaki kurimoto, katsuhiro maruyama, akira yoshitomo, satoru yoshida, satoru kitano (jun. 5, 2001) novolak type phenol resin, united state patent (6,242,533). 2200.. edwin s. smith (nov. 12, 1968) phenolformaldehyde novolak-phenol-formaldehyde resole molding surface for a reinforced matrix base sheet, united state patent (3,410,718). 2211.. npcs board of consultants & engineers, (08 jun 2009) phenolic resins technology handbook, niir project consultancy services. 2222.. richard m. lazarus, randall kautz, sunit s. dixit (apr. 24, 1990) high contrast high thermal stability positive photoresist with mixed cresol and hydroxybenzaldehyde prepared novolak and photosensitive diazoquinone. united state patent (4,920,028). 2233.. yoshitomo nakano, masumi kada (oct. 24, 1989) high molecular weight ortho cresol-novolak resins and process for the preparation thereof using alcoholic or acidic organic solvent, united state patent (4,876,324). http://www.springerlink.com/content/120534/?p=880589b4bdbf422e91846c9ddb8a673a&pi=0 http://www.springerlink.com/content/120534/?p=880589b4bdbf422e91846c9ddb8a673a&pi=0 http://www.springerlink.com/content/120534/?p=880589b4bdbf422e91846c9ddb8a673a&pi=0 available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.19 no.4 (december 2018) 13 – 19 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: fatimah kadhim idan, email: shemeriya93@gmail.com, saleem mohammed obyed, email: saleem_mo71@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. treatment of waste extract lubricating oil by thermal cracking process to produce light fractions fatimah kadhim idan and saleem mohammed obyed department of chemical engineering / al-nahrain university abstract this work deals with thermal cracking of three samples of extract lubricating oil produced as a by-product from furfural extraction process of lubricating oil base stock in al-dura refinery. the thermal cracking processes were carried out at a temperature range of 325-400 ºc and atmospheric pressure by batch laboratory reactor. the distillation of cracking liquid products was achieved by general astm distillation (astm d -86) for separation of gasoline fraction up to 220 ºc from light cycle oil fraction above 220 ºc. the comparison between the conversions at different operating conditions of thermal cracking processes indicates that a high conversion was obtained at 375°c, according to gasoline production. according to gasoline production, noticed that sample (3) was the best due to their high gasoline product at thermal cracking, so another distillation will occur to obtain other composition and its volume present. gasoline and kerosene conversion was 19 % and for light cycle oil 81% for the best one (sample 3). keywords: thermal cracking, furfural extraction, lubricating oil. received on 09/09/8102, accepted on 04/11/8102, published on 01/08/8102 https://doi.org/10.31699/ijcpe.2018.4.2 1introduction extract lubricating oil is a totally rich aromatic content by-product of furfural extracting process. this process is applied in refinery crude oil process to control the cost of the final output and to develop the viscosity index of various kind of lubricating oil fractions. normally extract lubricating oil has black color, which identified by high polycondensed aromatics and some lubricating oil fraction and also by high viscosity ‎[1]‎[2]. to reduce the aromatic compounds, different solvents like phenol ,furfural, cresol, sulfur dioxide, nitrobenzene, aniline, beta beta dichlor-ethyl ether, nitro-phenols, chlorinated phenols, pyridine, and many others, including mixtures of the foregoing with or without a modifying solvent ‎[3] are used in extraction process that is applied to extract the lubricating oil. the used solvent is removed from the outputs after the extraction and that make the residual rich of aromatic material (aromatic extract lubricating oil). according to the source of these compounds, these are described as residuum aromatic extracts (rae) if the oil base stock produces in vacuum process and distillate aromatic extracts (dae) if it produces in atmospheric distillation ‎[1]‎[2]. the applications of aromatic extract are relatively limited. the tires industry utilizes large quantities of an aromatic extract. on the other hand, plastic and rubber manufacture and asphalt blends utilize lower quantities‎[2] ‎[4]. the thermal breakdown of high molecular weight component into low molecular weight outputs is one of the initial transformation operations applied in the petroleum manufacturers, it was improved in the early 1900s and the specific sources of the operation are unexplained ‎[5]. it is a free radical chain reaction; a free radical is their mode of reaction that truly defines the product distribution through thermal cracking and it is referred to a group of atoms or just one atom holding an unpaired electron. free radical reactions are so reactive. when the free radical reacts with a hydrocarbon it creates a stabilized end output and a new free radical by removing a hydrogen atom ‎[6]. paraffins are hydrocarbons with the least thermal stability; the olefins created from the decomposition of paraffin are else reactive. the minimal readily decomposed hydrocarbons are naphthenes (cycloparaffins), their stability depending largely on any side chains present, but ring incision may happen, and dehydrogenation can lead to the production of unsaturated aromatics and naphthenes ‎[7]. the most stable (refractory) hydrocarbons are aromatics, their stability depending on the stability and the length of side chains. in the reaction of condensation reactions for ring components very hard thermal decomposition of high-boiling raw materials is able to occur, producing a high ratio of coke ‎[8]. https://doi.org/10.31699/ijcpe.2018.4.2 f. k. idan and s. m. obyed / iraqi journal of chemical and petroleum engineering 19,4 (2018) 13-19 41 the processes are based on the notes that the averages of the thermal breakdown progress at significantly greater averages in the case that in which the temperature of heating for petroleum fractions is in a surplus of 350°c (660f) ‎[9]‎[10]. in this work we study the characterizations of extract lubricating oil, the performance temperature for thermal cracking of extract lubricating oil at different operating conditions by batch laboratory unit and the characterizations of gasoline produced by thermal cracking and compare it with commercial gasoline and other fractions. 2experimental work 2.1. materials a. feed (extract lubricating oil) extract lubricating oil produced from the extraction unit of lubricating oil stock in al-dora refinery is utilized as a feedstock in this work. the properties of three samples for extract lubricating oil are shown in table 1. table 1. the physical and chemical properties of three samples for extract lubricating oil number of extract property 3 2 1 136.54 143.6 144.42 molecular weight (gm/gmole) 0.964 0.965 0.972 specific gravity 15.28 15 14.08 api 248 255 222 c mean average boiling point ( ) 478 491 495 k 74.5 71 78 c aniline point 166 160 172 f 25.36 24.2 24.27 diesel index 59 55.5 62.5 cetane index 1.547 1.546 1.561 refractive index 1.52 1.86 0.426 sulfur content % 24.77 20.25 30.6 aromatic content % 28 23 33.125 paraffinic content % 11.54 11.525 11.42 hydrogen content % 42.32 42.3 42. 3 heat content mj/kg b. distillation of extract lubricating oil table 2 shows the astm (american society for testing and materials) distillation of three samples of feed. table 2. the astm distillation of samples number of extracts temp. in c vol. % 3 ibp =140 2 ibp =86 1 ibp=140 146 176 156 5 160 182 178 10 166 178 172 15 196 194 190 20 171 198 194 25 194 205 198 30 190 240 216 35 222 210 210 40 262 230 214 45 256 156 220 50 164 198 210 55 190 200 234 60 244 246 238 65 166 260 250 70 250 266 248 75 254 270 252 80 256 278 258 85 260 287 262 90 262 296 268 95 264 305 272 100 table 3 shows the true boiling point (tbp) of the three samples. table 3. tbp of three type of feed volume % true boiling point °c sample (1) sample (2) sample (3) 0 110 60 110 10 162 166 143 30 193 201 189 50 223 157 260 70 259 269 165 90 275 301 273 95 280 304 274 2.2. the experimental unit the thermal cracking experiments were carried out in batch laboratory unit. fig. 1 shows the flow diagram of this unit, which includes: 1. batch reactor (250 ml), 2.temperature controller, 3.thermostat couple type k, 4.thermal insulator, 5.valves fitting, 6. electrical heater fig. 1. flow diagram of laboratory reactor unit f. k. idan and s. m. obyed / iraqi journal of chemical and petroleum engineering 19,4 (2018) 13-19 41 the reactor has a stainless steel tube with 5 cm inside diameter and 14 cm length and 250 ml volume. it was heated by one heater insulated by the jacket and carried by the climb and controlled automatically by digital control. the temperatures inside the reactor were measured by thermocouple fixed inside the reactor at the top. 2.3. the experimental procedure 105 ml of extract lubricating oil as a feed (1, 2 and 3) put in the batch reactor unit, that heated at a deferent temperature (325, 350, 375 and 400 °c) for four runs at residence time (30 minutes) for each run. 2.4 general distillation the common distillation of liquid products as a result of cracking was achieved according to astm d86. 3discussion 3.1. astm d-86 and tbp of the feed (extract lubricating oil) the distillation curves for the three samples of feed extract were listed in (fig. 2, fig. 3 and fig. 4). as shown in table 3 noticed that true boiling point distillation information gives an extra itemized description to extract lubricating oil volatility of. the initial boiling point (ibp) for tbp distillation test is minimum as well as its end boiling point (ep) is higher as compared with the test of astm because separation degree for it is much higher from that of the test of astm distillation. the curve of tbp (sketch for normal boiling point (nbp) against sample distilled percent volume) is commonly utilized like a principle for description the extract lubricating oil for purpose of design and analysis. fig. 2. astm d86 and true boiling point of sample (1) fig. 3. astm d86 and true boiling point of sample (2) fig. 4. astm d86 and true boiling point of sample (3) 3.2. thermal cracking the temperature effectiveness on the thermal cracking of three feed of extract lubricating oil which carried out by batch laboratory unit in order to obtained light fractions (gasoline and light cycle oil) were studied. table 4, table 5 and table 6, fig. 5, fig. 6 display the thermal decomposition outcomes at temperatures (325,350,375and 400) for each of the three samples (sample 1,2 and 3) respectively. the percentage of gasoline (% gasoline) was calculated by the amount of distillated gasoline by astm distillation per 100 ml of the cracked liquid. f. k. idan and s. m. obyed / iraqi journal of chemical and petroleum engineering 19,4 (2018) 13-19 41 table 4. material balance of thermal cracking of sample (1) temperature (c) volume (ml) liquid of extract cracking astm d.86 vol. of gasoline fraction at 220 °c vol. of light cycle oil at 220 °c 325 100 11 89 350 100 13 87 375 100 15 85 400 100 10 90 table 5.material balance of thermal cracking of sample (2) temperature (c) volume (ml) liquid of extract cracking astm d.86 vol. of gasoline fraction at 220 °c vol .of light cycle oil at 220 °c 325 100 12 88 350 100 14 86 375 100 16 84 400 100 11 89 table 6. material balance of thermal cracking of sample (3) temperature (c) volume (ml) liquid of extract cracking astm d.86 vol. of gasoline fraction at 220 °c vol .of light cycle oil at 220 °c 325 100 14 86 350 100 16 84 375 100 19 81 400 100 13 87 fig. 5. gasoline % produced from three samples by thermal cracking fig. 6. light cyclic oil % produced from three samples by thermal cracking as shown in the above tables and figures, transformation of extract lubricating oil rises by temperature rising. this may be attributed to the increase of temperature which accelerates intermolecular motion, assists the transformation of reactants into new compounds ‎[11]. the conversion of gasoline increases by increasing the temperature until it reaches 375 °c that at this temperature the conversion of gasoline reaches the best. after this temperature, higher temperature decreases the conversion of gasoline. on the other side, the light cycle oil (lco) decreases by temperature due to the increases in conversion with temperature increasing until it reaches 375°c, that at this temperature the conversion of lco reaches the minimum. by furthermore increasing in temperature after 375 °c the yield of light cycle oil will increase because of the decreasing in conversion of gasoline because the gasoline will be cracking at this temperature. production of unsaturated gasoline is the elementary step for extract lubricating oil decomposition and this product is commonly the required output. yet, the produced gasoline perhaps go under furthermore reaction which will be either oligomerization or cycloaddition for the compounds into dehydrogenated outputs as well as coke or subjected to side decomposition, which is commonly indicated to over decomposition, into gases component ‎[11]. furthermore, precipitated coke, as well as light side outputs, is produced by partly conversion of gasoline that produced like an intermediate output. each of these compounds minimizes the productivity of gasoline in the case of high amount of transformation for the extract lubricating oil. commonly, the transformation amount regulates in an amount equal to that of the highest gasoline in order to prohibit the incidence of this process of decay that damage the profit of the process ‎[12]. the mentioned results are accepted with those mentioned by reagan ‎[13]. as a comparison between the three samples, the production of gasoline increase in the (sample 3) and decrease in sample (1), as shown in fig. 5. on the other hand, the production of light cycle oil (lco) is larges in sample (1) and minimum in sample (3), as shown in fig. 6. as shown in table 1, there is not any extract lubricating oil sample that is constant in all of the properties and just change in one of the mentioned properties, so according to that the study of the effect of the different kind of extract lubricating oil sample on the production of gasoline is complicated. certainly, the structure, as well as the productivity of gasoline, is highly respected for the kind of raw material. and so on, hydrotreated or paraffinic feedstocks yield higher gasoline as compared with non-hydrotreated or aromatic feeds. at high transformation for the feed, the presence of aromatics is favorable for the produced gasoline and these are our explanation agree with lappas et al. ‎[14]. f. k. idan and s. m. obyed / iraqi journal of chemical and petroleum engineering 19,4 (2018) 13-19 41 at thermal decomposition of deferent raw materials, the content of saturated compound raises the reactivity of feedstock which also declines with the rising in the content of aromatic. higher transformation in thermal decomposition also occurs due to the minimum aromatic and higher hydrogen and saturated content. all of that make sample (3) gives higher productivity of gasoline. ‎[15]. from table 1, api for each one of the extract lubricating oil samples indicate that these samples are heavy and from the mean average boiling point of each one of these samples that mentioned in table 1, we can indicate the composition of oil fractions from the theoretical table of heavy fuel oil, table 7 ‎[16] and discover theoritacally that sample (3) of extract lubricating oil will give the largest amount of gasoline and that agree with practical part in this work.in table 7 the fractions are characterized as amixture of psedocomponent acording to their boiling point ranges (tb) and each psedo-component is characterized by average boiling point corresponds to unknown actual compounds (paraffins,naphthenes, aromatc). table 7. composition of oil fractions for heavy fuel oil ‎[16] oil fractions tb (°c) content(wt.%) c8-c12 (paraffins) 69-230 4.3 c13-c25 (paraffins) 230-405 10.1 c6-c12 (cycloparaffins) 70-230 1.4 c13-c23 (cycloparaffins) 230-405 3.4 c6-c11 (aromatics) 80-240 1.8 c12-c18 (aromatics) 240-400 4.3 c9-c25 (nephteon) 180-400 0 residuals >400 74.7 according to that and from the data in table 1 we can discuss the production of each extract lubricating oil sample: sample (1): molecular weight analysis: comparative high molecular weight (144.42 gm/gmol) which means heavier compounds more than saturated paraffins. composition: high aromatics (30.6%) will cause a decrease in the performance of catalytic cracking. mean average boiling point (tb) analysis: less saturated compounds that is why comparatively low boiling point (222 °c). sample (2): molecular weight analysis: high molecular weight (143.6 gm/gmol) which refers to higher molecular weight compounds. composition: comparatively low aromatics (20.25 %) but also low paraffins (23 %). mean average boiling point (tb) analysis: more saturated hydrocarbons that are why comparatively high boiling point (255°c), but the overall low percentage of paraffin only 23%. sample (3): molecular weight analysis: comparatively low molecular weight (136.54 gm/gmol) and high boiling point (248°c) shows more amount of saturated hydrocarbons. composition: significant paraffins (with high bp (248°c) and low mw (136.54 gm/gmol)) shows more saturated paraffins (28%) may be there, comparatively very low aromatics (24.77%) which can favor cracking mean average boiling point (tb) analysis: high boiling point and low mw shows high paraffins(saturated) hc. 3.3. the possibility of extract lubricating oil cracking uses the chemical composition of the produced gasoline using thermal cracking was tested by utilizing the differentiates in the composition and concentrations of five groups that are paraffins , isoparaffins, olefins, napthenes and aromatic which called piona test. piona composition for gasoline that produced is done in oil research and development center and described in table 8. table 8. the chemical compositions of cracked gasoline produced from sample (3) at 375 °c piona analysis total mass% n-paraffins 9.3 naphthenes 4.34 iso paraffins 30.1 aromatics 17.59 olefin 22.66 oxygenated 15.13 table 8 shows that the obtained gasoline in our practical part has low olefins content in compared with gasoline produced by esgair ‎[17], who explained that the olefins content in yielded gasoline is 34.1%. the reason for that may be hydrogen transfer reactions growing that in which olefins with naphthenes reaction produce paraffins as well as aromatics. naphthenic components are able to react with olefins yielding aromatics as well as paraffins because these compounds are hydrogen donors. since the extra reactive bonds are the double bonds are more reactive which simply polymerized as well as oxidized causing the production varnishes, as well as gums, injection nozzles and valves of automobiles, will be blocked due to the gasoline high olefin content ‎[18]. f. k. idan and s. m. obyed / iraqi journal of chemical and petroleum engineering 19,4 (2018) 13-19 41 it also can be noticed that gasoline which formed from this thermal decomposition has a lot of aromatics as well as isoparaffins and that cause high research octane number (ron) for this product. toluene, 1,3dimethylbenzene, and isobutyl benzene are the aromatic compounds that present in produced gasoline and those have high ron which is 111, 115, and 112 ron, respectively for each of them while isoparaffin compounds have high octane numbers (85-100) ‎[19]. baker et al. ‎[20] noticed that the research octane number fundamentally respected on the content of aromatic, fig. 7 explain this relation, and he also determined the chemical composition for decomposed gasoline obtained from various raw materials. gasoline yielded in this work has a research octane number (ron) that was measured by the equation of fig. 7 (aromatics = 2.436ron – 191.9), which was 86 for thermal cracking. finally, it is able to utilize the gasoline that yielded by the decomposition of extract lubricating oil as a useful requisite gasoline for regular and premium automobile gasoline yield because the minimum research octane number of regular and premium iraqi gasoline are 85 and 90, respectively ‎[21]. fig. 7. relation between ron and aromatic content for cracked gasoline ‎[21]. table 9 shows the characteristics of produced gasoline produced by thermal cracking and required properties of this fraction. table 9. the characteristics of produced gasoline characteristics value thermal cracking iraqi commercial value[21] specific gravity, 15.6 ºc/15.6 ºc 0.81 0.775 api gravity 43.191 51.00 net heat, mj/ kg. 10995 11000 octane number 86 85 the gasoline has an octane number identical to the required. 4conclusions uses of the raw material for this project (extract lubricating oil) are almost limited but it has the ability to crack because of its high molecular weight so we can crack it to produce gasoline, kerosene, gas oil and lubricating oil. study of the effect of thermal cracking on the extract lubricating oil in a batch laboratory reactor show that increasing of reaction temperature from 325°c to 375°c gives higher conversion and as a based on the maximum of the gasoline yield, it could be said that the best cracking temperature was 375ºc and sample (3) gives more gasoline yield. gasoline yield increase in the run of 375 °c where it is 19 ml for thermal cracking, after this temperature the yield decrease because the gasoline itself will crack and light cycle oil yield increase in the run of 400 °c where it is 87 ml for thermal cracking. from the piona analysis, the produced gasoline has high research octane number because it has high aromatics and isoparaffins. this means that it is possible to use gasoline for the automobile. references [1] r. sadeghbeigi, “fluid catalytic cracking handbook: design, operation and troubleshooting of fcc facilities.” gulf publishing company. houston, tx, 2000. [2] j. deruiter, “hydrocarbon structure and chemistry: aromatics,” 2005. [3] h. h. gross, “refining of lubricating oil extracts.” u.s. patent no. 2,726,986, patent and trademark office, 13-dec-1955. [4] the petroleum hpv testing group, “aromatic extracts category,” 2008. [5] speight,j. g., handbook of petroleum refining. crc press, 2016. [6] speight,j. g., the chemistry and technology of petroleum, 4th ed. taylor and francis group, llc, 2007. [7] hsu ,c. s. and p. r. robinson, practical advances in petroleum processing, vol. 1 & 2. springer science & business media, new york, 2007. [8] d. i. exall and j. g. speight, refining used lubricating oils. crc press, 2014. [9] j. g. speight and b. ozum, petroleum refining processes. marcel dekker inc., new york., 2002. [10] s. parkash, refining processes handbook. elsevier, 2003. [11] d. decroocq, catalytic cracking of heavy petroleum fractions. editions technip, 1984. [12] j. h. gary and g. e. handwerk, petroleum refining: technology and economics, 4th ed. marcel dekker, new york, 2001. http://www.auburn.edu/~deruija/pda1_aromatics.pdf http://www.auburn.edu/~deruija/pda1_aromatics.pdf https://patents.google.com/patent/us2726986a/en https://patents.google.com/patent/us2726986a/en https://patents.google.com/patent/us2726986a/en https://www.taylorfrancis.com/books/9781466591615 https://www.taylorfrancis.com/books/9781466591615 https://books.google.iq/books?hl=en&lr=&id=jaoq7qxcwkyc&oi=fnd&pg=pa1&dq=%5b7%5d%09hsu+,c.+s.+and+p.+r.+robinson,+practical+advances+in+petroleum+processing,+vol.+1+%26+2.+springer+science+%26+business+media,+new+york,+2007.&ots=8ayvyk7hqb&sig=6hmnrumqkhzakrc1xby9dnzqhli&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=jaoq7qxcwkyc&oi=fnd&pg=pa1&dq=%5b7%5d%09hsu+,c.+s.+and+p.+r.+robinson,+practical+advances+in+petroleum+processing,+vol.+1+%26+2.+springer+science+%26+business+media,+new+york,+2007.&ots=8ayvyk7hqb&sig=6hmnrumqkhzakrc1xby9dnzqhli&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=jaoq7qxcwkyc&oi=fnd&pg=pa1&dq=%5b7%5d%09hsu+,c.+s.+and+p.+r.+robinson,+practical+advances+in+petroleum+processing,+vol.+1+%26+2.+springer+science+%26+business+media,+new+york,+2007.&ots=8ayvyk7hqb&sig=6hmnrumqkhzakrc1xby9dnzqhli&redir_esc=y#v=onepage&q&f=false https://www.taylorfrancis.com/books/9781466551503 https://www.taylorfrancis.com/books/9781466551503 https://books.google.iq/books?hl=en&lr=&id=fwwl64ureq4c&oi=fnd&pg=pp1&dq=%5b10%5d%09s.+parkash,+refining+processes+handbook.+elsevier,+2003.&ots=qht_ht30rx&sig=f07hloqpw-hwcdnhpthvkuhy7ay&redir_esc=y#v=onepage&q=%5b10%5d%09s.%20parkash%2c%20refining%20processes%20handbook.%20elsevier%2c%202003.&f=false https://books.google.iq/books?hl=en&lr=&id=fwwl64ureq4c&oi=fnd&pg=pp1&dq=%5b10%5d%09s.+parkash,+refining+processes+handbook.+elsevier,+2003.&ots=qht_ht30rx&sig=f07hloqpw-hwcdnhpthvkuhy7ay&redir_esc=y#v=onepage&q=%5b10%5d%09s.%20parkash%2c%20refining%20processes%20handbook.%20elsevier%2c%202003.&f=false https://books.google.iq/books?hl=en&lr=&id=fhjzyzdymeac&oi=fnd&pg=pr5&dq=%5b11%5d%09d.+decroocq,+catalytic+cracking+of+heavy+petroleum+fractions.+editions+technip,+1984.&ots=zsxy2zq4kt&sig=igrtfexqufo0cqgrn4xnk5tl-je&redir_esc=y#v=onepage&q=%5b11%5d%09d.%20decroocq%2c%20catalytic%20cracking%20of%20heavy%20petroleum%20fractions.%20editions%20technip%2c%201984.&f=false https://books.google.iq/books?hl=en&lr=&id=fhjzyzdymeac&oi=fnd&pg=pr5&dq=%5b11%5d%09d.+decroocq,+catalytic+cracking+of+heavy+petroleum+fractions.+editions+technip,+1984.&ots=zsxy2zq4kt&sig=igrtfexqufo0cqgrn4xnk5tl-je&redir_esc=y#v=onepage&q=%5b11%5d%09d.%20decroocq%2c%20catalytic%20cracking%20of%20heavy%20petroleum%20fractions.%20editions%20technip%2c%201984.&f=false https://content.taylorfrancis.com/books/download?dac=c2009-0-12513-2&isbn=9780203907924&format=googlepreviewpdf https://content.taylorfrancis.com/books/download?dac=c2009-0-12513-2&isbn=9780203907924&format=googlepreviewpdf https://content.taylorfrancis.com/books/download?dac=c2009-0-12513-2&isbn=9780203907924&format=googlepreviewpdf f. k. idan and s. m. obyed / iraqi journal of chemical and petroleum engineering 19,4 (2018) 13-19 41 [13] w. j. reagan, “us department of energy, pittsburgh energy technology center, liquefaction conttractors’ review,” in conference proceedings, september, 1992, pp. 261–290. [14] a. a. lappas, d. k. iatridis, and i. a. vasalos, “production of reformulated gasoline in the fcc unit. effect of feedstock type on gasoline composition,” catal. today, vol. 50, no. 1, pp. 73–85, 1999. [15] d. stratiev et al., “effect of feedstock properties on conversion and yields,” oil gas-european mag., vol. 43, no. 2, pp. 84–89, 2017. [16] mike 2017, dhi spill data analysis data sheet: data sheets for diffetent oil, heavy fuel oil, 9-10. [17] k. k. esgair and ak mohammed “fluid catalytic cracking of petroleum fraction (vacuum gas oil) to produce gasoline,” iraqi journal of chemical and petroleum eengineering, 33-45, 2010. [18] p. ghosh, k. j. hickey, and s. b. jaffe, “development of a detailed gasoline compositionbased octane model,” ind. eng. chem. res., vol. 45, no. 1, pp. 337–345, 2006. [19] p. t. m. do, s. crossley, m. santikunaporn, and d. e. resasco, “catalytic strategies for improving specific fuel properties,” catalysis, vol. 20, pp. 33–64, 2007. [20] r. w. baker, “presentation at the davison– crosfield catalyst symposium,” gt. british, april, 1972. [21] ministry of oil republic of iraqi, “marketing specification guide of iraqi petroleum,” 2013. معالجة المتبقي من مستخمص زيوت التزييت باستخدام التكسير الحراري إلنتاج مقاطع خفيفه الخالصة يتعامل ىذا البحث مع التكسير الحراري لثالث نماذج من مستخمص زيوت التزييت الناتج من وحدة االستخالص باستخدام الفيرفرال لزيوت التزييت في مصفى الدورة.تمت عممية التكسير الحراري بمعدل درجات قطير سائل التكسير الناتج من س و تحت الضغط الجوي باستخدام مفاعل مختبري. تم ت° 044-523حراره س عن المقاطع °224و ذلك لعزل الكازولين عند درجة حرارة تصل الى (astm d -86)العممية باستخدام س .لقد بينت المقارنو بين نسب التحويل في الظروف المختمفة ° 224الالخرى في درجات حرارة اعمى من س اعتمادأ عمى الكازولين الناتج . ° 573لمتكسير الحراري ان افضل نسبة تحويل كانت عند درجة حرارة ( كان االفضل في انتاج 5ينت المقارنة بين الكازولين الناتج من النماذج المختمفة ان النموذج )كما ب الكازولين بالتكسير الحراري لذا تم اجراء عممية تقطير اخرى لمناتج من النموذج لعزل المقاطع االخرى عن (.5بة لمنموذج االفضل )نموذج % بالنس19% و لبقية المقاطع 91الكازولين . نسبة التحويل لمكازولين كانت https://www.sciencedirect.com/science/article/pii/s0920586198004647 https://www.sciencedirect.com/science/article/pii/s0920586198004647 https://www.sciencedirect.com/science/article/pii/s0920586198004647 https://www.sciencedirect.com/science/article/pii/s0920586198004647 https://www.researchgate.net/profile/dicho_stratiev2/publication/319095410_fluid_catalytic_cracking_and_thermal_cracking_of_vacuum_gas_oils_-_effect_of_feedstock_properties_on_conversion_and_yields/links/59d4cb50a6fdcc181adc5734/fluid-catalytic-cracking-and-thermal-cracking-of-vacuum-gas-oils-effect-of-feedstock-properties-on-conversion-and-yields.pdf https://www.researchgate.net/profile/dicho_stratiev2/publication/319095410_fluid_catalytic_cracking_and_thermal_cracking_of_vacuum_gas_oils_-_effect_of_feedstock_properties_on_conversion_and_yields/links/59d4cb50a6fdcc181adc5734/fluid-catalytic-cracking-and-thermal-cracking-of-vacuum-gas-oils-effect-of-feedstock-properties-on-conversion-and-yields.pdf https://www.researchgate.net/profile/dicho_stratiev2/publication/319095410_fluid_catalytic_cracking_and_thermal_cracking_of_vacuum_gas_oils_-_effect_of_feedstock_properties_on_conversion_and_yields/links/59d4cb50a6fdcc181adc5734/fluid-catalytic-cracking-and-thermal-cracking-of-vacuum-gas-oils-effect-of-feedstock-properties-on-conversion-and-yields.pdf http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/389 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/389 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/389 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/389 https://pubs.acs.org/doi/abs/10.1021/ie050811h https://pubs.acs.org/doi/abs/10.1021/ie050811h https://pubs.acs.org/doi/abs/10.1021/ie050811h https://pubs.acs.org/doi/abs/10.1021/ie050811h https://books.google.iq/books?hl=en&lr=&id=yhk14mbmngac&oi=fnd&pg=pa33&dq=%5b19%5d%09p.+t.+m.+do,+s.+crossley,+m.+santikunaporn,+and+d.+e.+resasco,+%e2%80%9ccatalytic+strategies+for+improving+speci%ef%ac%81c+fuel+properties,%e2%80%9d+catalysis,+vol.+20,+pp.+33%e2%80%9364,+2007.&ots=pddgg2vsgn&sig=5plkx112jrmjwbm3j7zc1qtnwxo&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=yhk14mbmngac&oi=fnd&pg=pa33&dq=%5b19%5d%09p.+t.+m.+do,+s.+crossley,+m.+santikunaporn,+and+d.+e.+resasco,+%e2%80%9ccatalytic+strategies+for+improving+speci%ef%ac%81c+fuel+properties,%e2%80%9d+catalysis,+vol.+20,+pp.+33%e2%80%9364,+2007.&ots=pddgg2vsgn&sig=5plkx112jrmjwbm3j7zc1qtnwxo&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=yhk14mbmngac&oi=fnd&pg=pa33&dq=%5b19%5d%09p.+t.+m.+do,+s.+crossley,+m.+santikunaporn,+and+d.+e.+resasco,+%e2%80%9ccatalytic+strategies+for+improving+speci%ef%ac%81c+fuel+properties,%e2%80%9d+catalysis,+vol.+20,+pp.+33%e2%80%9364,+2007.&ots=pddgg2vsgn&sig=5plkx112jrmjwbm3j7zc1qtnwxo&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=yhk14mbmngac&oi=fnd&pg=pa33&dq=%5b19%5d%09p.+t.+m.+do,+s.+crossley,+m.+santikunaporn,+and+d.+e.+resasco,+%e2%80%9ccatalytic+strategies+for+improving+speci%ef%ac%81c+fuel+properties,%e2%80%9d+catalysis,+vol.+20,+pp.+33%e2%80%9364,+2007.&ots=pddgg2vsgn&sig=5plkx112jrmjwbm3j7zc1qtnwxo&redir_esc=y#v=onepage&q&f=false dr abdul-halim _mag_.doc ijcpe vol.8 no.4 (december 2007) 1 iraqi journal of chemical and petroleum engineering vol.8 no.4 (december 2007) 1-12 issn: 1997 -4884 the effect of solvent extraction of light lubricating oil on viscosity index and chemical composition abdul-halim a.-k. mohammed, hussain k. hussain, and rafal j. sadiq chemical engineering department college of engineering university of baghdad iraq abstract an investigation was conducted for the improvement of viscosity index of light lubricating oil fraction (40 stock) obtained from vacuum distillation unit of lube oil plant of daura refinery, using solvent extraction process. in this study furfural solvent was used to extract the undesirable materials which reduce the viscosity index of raw lubricating oil fraction. the studied effecting variables of extraction were extraction temperature range from 70 to 110°c, and solvent to oil ratio range from 1:1 to 4:1 (wt/wt). the n-d-m method was used for calculation of carbon distribution and structural group analysis of the raffinate produced from furfural extraction. also the three component phase diagram for a mixed-base oil and furfural at different temperature was drawn. the results of this investigation show that the viscosity index of lubricating oil fraction increases with increasing extraction temperature and increasing the solvent to oil ratio and reaches 115.6 at extraction temperature 110°c and solvent to oil ratio 4:1. further more, the results show that the viscosity, refractive index, density, sulfur content and percentage yield of produced raffinate were decreased as the extraction temperature or solvent to oil ratio increases for extraction process. keywords: solvent extraction, lubricating oil, furfural. introduction since the beginning of the petroleum industry, solvent extraction has been interest to refiners as a means of removing polyaromatics and other undesirable constituents from lubricating oils(1). the most important properties of a lubricating oil which solvent extraction is meant to improve are viscosity–temperature characteristics, stability toward oxidation, and carbon residue. the improvement of these properties is accomplished almost entirely by the extraction of aromatics(2). a strong temptation to produce high viscosity index lubes has led to a prolific growth of solvent extraction. solvents widely used for this affair are furfural, phenol, mixture of cresols and propane. many other solvents like aniline, sulfur dioxide are enlisted; but with out much use(3). although there are technical advantages for each of these solvent’s, furfural remain the solvent of choice in many parts of the world. the major factors favoring its use are low toxicity, cost, availability, history of commercial experience, adaptability to extraction of gas oil and better selectivity in the extractio n of these lube stocks which exhibit excellent refining response at low solvent to oil ratios(1). in the 1990s, a world wide trend began to manufacture higher-viscosity index vi, lowervolatility, paraffinic base oils for automotive applications. these new paraffinic base oils, in the 110-140 vi range, are expected to become more readily available and more commonly used to blend lubricants in the 21st century(4). the improvement in the properties of an oil gained by solvent refining is some what dependent o n the properties of the original stock as well as the type of kind of solvent employed, and since base oils differ widely in molecular university of baghdad college of engineering iraqi journal of chemical and petrole um engineering the effect of solvent extraction of light lubricating oil on viscosity index and chemical composition ijcpe vol.8 no.4 (december 2007) 2 composition and physical properties due to the crude source, hence each refiner must satisfy himself by laboratory tests and studying in detail the selected fraction of lubricating oil. the purpose of this investigation is to improve the viscosity index of light lubricating oil fraction (40 stock) obtained from vacuum distillation unit of lube oil plant of daura refinery, by extremely solvent extraction process using furfural. the present study includes a detail investigation of the effect of extraction temperature and solvent to oil ratio on physical properties, sulfur content, chemical composition, and the percentage yield of the product lubricating oil. in addition, the three-component phase diagram of the extraction process was drawn at different temperatures. experimental work feedstock in this work a light lube oil distillate fraction (40 stock) with boiling point range 316-326°c obtained from vacuum distillation unit of lube oil plant of daura refinery was used. the feedstock for vacuum distillation unit was atmospheric residue produced from mixed iraqi crude oils (60 % of basrah, 30 % of kirkuk and 10 % of sharki-baghdad). table 1 shows the properties of the light lube oil fraction. table 1 properties of the light lube oil fraction (40 stock). no. specification values 1 viscosity, cst, @ 40°c 15.773 2 viscosity, cst, @ 100°c 30.336 3 viscosity index 66 4 specific gravity@ 60/60 °f 0.91 5 coc flash point, °c 168 6 pour point, °c 18 7 sulfur content, % wt 2.6015 8 color, astm-d1500, at 25°c 5 9 refractive index ( 25 dn ) 1.4971 solvent the solvent used in this work is furfural (liaosin private limited company, china). table 2 shows the properties of this solvent. table 2 properties of furfural no. specification values 1 boiling point, °c 161 2 freezing point, °c -36.5 3 viscosity, cps, @25°c 1.49 4 density (d254), g/cm3 1.1563 5 coc flash point, °c 68 6 refractive index ( 25 dn ) 1.5235 extraction experiments 1. contacting step in the present work a laboratory batch extraction unit was used. figure 1 shows the process flow diagram of the laboratory extraction unit.this unit consists of a bench scale 1-liter, 3-necks pyrex flask extraction apparatus. the middle flask neck was connected with the mixer; the second neck was connected with recycle condenser and the third neck was connected with thermometer. electrical mixer was used to mix the feedstock with the extraction solvent inside the flash extractor with 45 mm diameter paddle. the flask extractor was heated and controlled by using an oil bath (with heater and thermostat) in which the flask extractor is immersed. the lube oil fraction was mixed with the extraction solvent in the extractor at controlled specified temperature. mixing the two materials at the specified temperature was continued for a period of 30 min then the mixture was left at the specified temperature fo r 30 min to be separated in to two phases. the upper liquid phases is light raffinate solution and the bottom liquid phase is heavier extract solution. after steady state indicated by constant interface level, the two phases were separated by using a separating funnel. the two solutions were weighted to ensure material balance closure. figure 1 flow diagram of the laboratory extraction unit. 2. solvent recovery the solvent was stripped from the raffinate solution by distillation under vacuum about (0.2 bar) to avoid decomposition, and from the extract solution by atmospheric distillation. figure 2 shows the process flow diagram of the laboratory vacuum distillation unit. abdul halim a.-k. mohammed et al ijcpe vol.8 no.4 (december 2007) 3 the unit consists of a 500 ml, 2 necks pyrex flask, the middle flask neck was connected with thermometer (to indicate vapour temperature) and double wall condenser. at the end of condenser there is a receiver which connected with a trap and vacuum pump with a vacuum gage pressure. the second flask neck was connected with thermometer (to indicate the solution temperature). the raffinate and extract solutions were heated in the flask using heating mantle with a regulator to control heat supply. the stripped raffinate was weighted and the raffinate yield was obtained. figure 2 flow diagr am of the vacuum distillation unit extraction experiment conditions the operating conditions of the set of experiments that applied on the extraction of light lube oil distillate fraction (40 stock) by furfural were extraction temperature range from 70 to 110°c, and solvent to oil ratio range from 1:1 to 4:1 (wt./wt.). the pressure was kept constant at atmospheric pressure. table 3 shows the details of extraction experiments. table 3 details of extraction experiment no. temperature, °c solvent to oil ratio (wt /wt ) 1 70 1:1 2 70 2:1 3 70 3:1 4 70 4:1 5 80 1:1 6 80 2:1 7 80 3:1 8 80 4:1 9 90 1:1 10 90 2:1 11 90 3:1 12 90 4:1 13 100 1:1 14 100 2:1 15 100 3:1 16 100 4:1 17 110 1:1 18 110 2:1 19 110 3:1 20 110 4:1 test methods 1. density and specific gravity the density and specific gravity of lubricating oil were measured according to astm-d1481 (5). density is define as mass per unit volume and specific gravity of the test liquid is obtained by dividing its density by the density of water at the test temperature (6,7). the liquid was drawn into the bicapillary pycnometer through the removable siphon arm and adjusted to volume at the temperature of test, in such a manner that there is practically no drainage in the unfilled tubing. after equ ilibration at the test temperature, liquid levels were read, and the pycnometer was removed from the thermostated bath, cooled to room temperature, and weighted. from the weight of the sample and the volume at the test temperature density is calculated (5). the density of the petroleum product reduces by 0.00062 per celsius degree of temperature rise (7). specific gravity at the test temperature is converted to specific gravity at 60/60°f by using figure which relates the specific gravity at 60/60°f with the specific gravity at other temperature (8). 2. viscosity the viscosity of lubricating oil was measured according to astm-d445 (9). this test method specifies a procedure for the determination of the kinematic viscosity, v, of liquid petroleum products, bo th transparent and opaque, by measuring the time for a volume of liquid to flow under gravity through a calibrated glass capillary u-tube viscometer (5). the lube oil distillate fraction and raffinate oil sample is charged in the viscometer, and then the v iscometer is immersed in an oil bath which maintained at a constant temperature of 100°c (to measure the viscosity at 40°c it immersed in a water bath which maintained at constant temperature of 40°c). after 20 minutes to achieve thermal equilibrium between the sample and the bath temperature, the sample dragged then the time in second is recorded for flow of oil sample between the two levels in the capillary tube. the kinematic viscosity can be calculated by applying equation 1. v=c î t (1) c= constant factor of the calibrated viscometer. t = time in second. v = kinamatic viscosity measured in mm2/s (centistocke, cst). 3. viscosity index the viscosity index of lube oil distillate fraction and raffinate oil were calculated according to astm-d2270 (9), by appling the procedure for oils of zero to 100 vi. in the effect of solvent extraction of light lubricating oil on viscosity index and chemical composition ijcpe vol.8 no.4 (december 2007) 4 this procedure the kinematic viscosity of lube oil at 40 and 100°c is measured and equation 2 was used. 100× − −= hl ulvi (2) where u= kinematic viscosity at 40°c of the oil whose viscosity index to be calculated (cst). l= kinamatic viscosity at 40°c of an oil of zero viscosity index having the same kinamatic viscosity at 100°c as the oil whose viscosity index is to be calculated (cst). h = kinamatic viscosity at 40°c of an oil of 100 viscosity index having the same kinematic viscosity at 100°c as the oil whose viscosity index is to be calculated (cst). the value of l and h can be obtained from tables. for oils having a viscosity index greater than 100, another viscosity index scale has been created. for this index, the oil is only compared with a reference oil of the h family having the same viscosity at 100°c, and by applying equation 3 (7). viscosity index= ( )[ ] 10000715.0/110 +−n (3) where b uhn log loglog −= b= the kinematic v iscosity of the oil at 100°c 4. refractive index the refractive index of lubricating oil was measured according to astm-d1218 (5). the refractive index is measured by the critical angle method with a bausch and lomb precision refractometer using monochro matic light. this method is used for hydrocarbons having an astm color less than 4 and it is limited to measuring refractive indices between 1.33 and 1.50, for temperature between 20 and 30°c (7). 5. color the color of lubricating oil was measured accordin g to astm-d1500 (5), by using a standard light source, a liquid sample is placed in the test container and compared with colored glass disks ranging in value from 0.5 to 8.0 when an exact match is not found and the sample color falls between two standard colors, the higher of the two colors is reported. 6.sulfur content the sulfur content of lubricating oil was measured according to astm-d2622(5), with a fluorescence analyzer of x-rays. this method uses to measure sulfur levels in the 0.001-5.000% range (6) . a sample is placed in an x-ray beam, and the peak intensity of the sulfur kα line at 5.373å is measured. the background intensity, measured at 5.190å is subtracted from the peak intensity. the resultant net counting rate is then compared to a previously prepared calibration curve or equation to obtain the sulfur concentration in mass percent. 7. molecular weight molecular weight is a fundamental physical constant that can be used in conjugation with other physical properties to characterize pure hydrocarbons and their mixtures (5). a knowledge of molecular weight is necessary for the application of a number of correlative methods (such as in n-d-m method in the present work) that are useful in determining the gross composition of the heavier fractions of petroleum (5). the molecular weight of petroleum fractions in the 70350 range can be approximated from boiling points and density (10). the molecular weight of lube oil was determined by using equation 4 (11). 4.0 , ../ grsptm ca °= (4) where m= molecular weight g/gmol. ta,°c= molal average boiling point of lube oil fraction. sp.gr.= specific gravity at 60/60°f of lube oil. calculation of carbon distribution and structural group analysis of lube oils by the n-d-m method n-d-m method was applied on lube oil distillate fraction and raffinate oil according to astm-d3238 (12). this method covers the calculation of the carbon distribution and ring content of lube oils from measurements of refractive index, density and molecular weight. the refractive index and density of the oil are determined at 20°c. these data are then used to calculate the carbon distribution (%ca, %cn, %cp) or the ring analysis (ra, rn) using the appropriate set of the following equations: ( ) ( )8510.04750.151.2 20420 −−−= dnv d (5) ( ) ( )4750.111.18510.0 20204 −−−= dndw (6) where v and w are factors 20 4d = relative density at 20°c 20 dn = refractive index at 20°c abdul halim a.-k. mohammed et al ijcpe vol.8 no.4 (december 2007) 5 to calculate the percentage of aromatic carbon (%ca): if v is positive: % ca= 430 v + 3660/m (7) if v is negative: % ca= 670 v + 3660/m (8) where m= molecular weight to calculate the percentage of carbon in total aromatic and naphthenic) ring structures (%cr): if w is positive: %cr= 820 w -3s+10000/m (9) if w is negative: %cr= 1440 w -3s+10600/m (10) where s= weight % sulfur to calculate the percentage of naphthenic carbon (%cn) and the percentage of paraffinic carbon (%cp): %cn= %cr %ca (11) %cp= 100 %cr (12) to calculate the average number of aromatic rings per molecule (ra): if v is positive: ra= 0. 44 + 0.055m v (13) if v is negative: ra= 0.44 + 0.080m v (14) to calculate the average total number of rings per molecule (rt) if w is positive: rt= 1.33+0.146m( w -0.005s) (15) if w is negative: rt= 1.33 + 0.180m( w -0.005s) (16) to calculate the average number of naphthene rings per molecule (rn) rn= rt – ra (17) the triangular coordinate graphical method when solvent extraction is employed for the removal of undesirable constituents from petroleum products, such as in the present work the extraction of aromatics from lubricating oil by furfural, the equilibria involved cannot be represented exactly by any simple means. exact representation can be obtained only by the use of complex methods involving a comprehensive knowledge of the constituents of such petroleum products (13). the resulting oil-solvent system may be treated as a simple ternary system and equilibrium relations represented on triangular coordinates in terms of solvent, extract (naphthenic), and raffinate (paraffinic). the equilibrium diagram can be constructed from the experimental results obtained by the single -stage batch extraction of an oil with different volumes of solvent (13). in order to represent the equilibrium relations in an oil-solvent system, it is necessary only to record by some suitable means the following information (13): amounts of the two phases in equilibrium. amount of solvent in each phase at equilibrium. a physical property of the oil present in each phase at equilibrium (in this work specific gravity at 60/60°f was used). item 2 and 3 of this information can be recorded by a single point on a triangular graph of wh ich one vertex represent pure solvent and one side, opposite this vertex, is scaled into units representing the required physical property of the solvent-free oil. the equilibrium resulting between a lubricating oil (of the present work) and furfural at 90°c is shown in table 4. these equilibrium relationships are plotted on the triangular graph, figure 3. the specific gravity of the solvent-free oil in the raffinate layer from experiment 1 of table 4 is given by point a on this diagram (figure 3). if raffinate oil of this, specific gravity was mixed with an amount of furfural such that the total mixture contained 16.4 volume percent of furfural, the actual raffinate layer should be obtained. therefore by joining point a to the apex of the triangle representing 100 percent of furfural and locating the point on this line where the furfural content is 16.4 volume percent, point a representing the composition of the raffinate layer can be obtained. this may be shown in another way by staring with the raffinate layer of composition a and removing all the solvent present, point a would be obtained on the diagram, which is solvent-free oil of specific gravity 0.8925. the composition of the various raffinate and extract layer is therefore easily ascertained and is indicated on figure a-1 by points dcba ,,, and dcba ′′′′ ,,, for the experimentals 1, 2, 3, and 4 quoted in table 4. returning again to experiment 1, the composition of the raffinate and extract layers in equilibrium are given by points a and a′ . these two solutions are conjugate and hence may be joined by the tie line a a′ . mixtures of oil and furfural whose compositions fall within the two-phase region under the curve will separate into two layers whose composition are shown by the ends of the tie lines labeled a a′, bb ′, cc ′ ,and dd ′ . the four tie lines represent experimental data, but additional tie lines can be estimated as necessary. the completed isothermal binodial curve and tie lines represented the equilibrium relations for lube oil-furfural system at 90°c was shown in figure a3. the effect of solvent extraction of light lubricating oil on viscosity index and chemical composition ijcpe vol.8 no.4 (december 2007) 6 table 4 the equilibrium data of three-component system of a mixed-light lube oil fraction (40 stock) and furfural at 90°c raffinate layer extract layer expert. solvent to oil ratio wt/wt specific gravity at 60/60°f of oil in layer vol.% solvent in layer specific gravity at 60/60°f of oil in layer vol.% solvent in layer 1 1:1 0.8925 16.40 1.0000 75.3 2 2:1 0.8785 13.10 0.9825 81.0 3 3:1 0.8537 10.11 0.9700 85.0 4 4:1 0.8400 9.770 0.9578 85.6 figure 3 three-component phase diagram for a mixed-light lube oil fraction (40 stock) and furfural at 90°c results and discussion the effect of extraction temperature and solvent to oil ratio on raffinate viscosity and viscosity index the viscosity of lubricating oil fraction is very important factor in the manufacture of lubricating oils, and the correct operation of the equipment depends upon the appropriate viscosity of the lubricating oil being used. the ability of lube oil viscosity to vary with temperature reflects the viscosity index of lubricating oil. in the present work the effect of extraction temperature and solvent to oil ratio on raffinate kinematic viscosity measured at 40 and 100°c was studied. figures 4 and 5 show the effect of extraction temperature on raffinate viscosity measured at 40 and 100°c, respectively at various solvent to oil ratio, while figures 3 and 4 show the effect of solvent to oil ratio on raffinate viscosity measured at 40 and 100°c, respectively, at various extraction temperatures. in general, the viscosity of raffinate produced from extraction decreases with increasing the extraction temperature or increasing the solvent to oil ratio. this is due to the extraction of high molecular weight aromatic materials, especially, polycondensed aromatics from the raw lubricating oil fraction. the high molecular weight aromatics have the higher viscosity among the hydrocarbons that presented in raw lubricating oils and the extraction of these materials decreases its content in the produced raffinate and increases the paraffins content which have a vis cosity relatively lower than that of aromatics as mentioned by kosters (14). figures 4 and 5 clearly indicated that the extraction temperature slightly effect on the produced raffinate viscosity measured at 40 and 100°c for a given solvent to oil ratio. figures 6 and 7 show that the increase in solvent to oil ratio for a given extraction temperature has higher effect on decreasing the raffinate viscosity measured at 40 and 100°c, respectively because of the high removing of aromatic compounds with increasing solvent to oil ratio. figure 4 effect of extraction temperature on raffinate viscosity at 40°c at various solvent to oil ratio figure 5 effect of extraction temperature on raffinate viscosity at 100°c using different solvent to oil ratio. abdul halim a.-k. mohammed et al ijcpe vol.8 no.4 (december 2007) 7 figure 6 effect of solvent to oil ratio on raffinate viscosity at 40°c at various extraction temperatures figure 7 effect of solvent to oil ratio on raffinate viscosity at 100°c at various extraction temperatures figure 8 effect of extraction temperature on raffinate viscosity index at various solvent to oil ratio figure 8 shows the effect of extraction temperature on raffinate viscosity index at various solvent to oil ratio, while figure 9 shows the effect of solvent to oil ratio on raffinate viscosity index at various extraction temperatures. the increase in extraction temperature will encourage the solubility of undesirable materials in extraction solvent especially polycondensed aromatics which reduces the viscosity index of lubricating oil. it is obvious form figure 8 that the viscosity index of lubricating oil fraction increases with increasing the extraction temperature. figure 9 indicates that the increase in solvent to oil ratio has a higher effect on increasing the viscosity index of lubricating oil fraction than the effect of increasing the extraction temperature. figure 9 effect of solvent to oil ratio on raffinate viscosity index at various extraction temperatures the effect of extraction temperature and solvent to oil ratio on raffinate yield figure 10 explains the effect of extraction temperature on raffinate yield at various solvent to oil ratio, while figure 11 shows the effect of solvent to oil ratio on raffinate yield at various extraction temperatures. usually, on raising the temperature the solvent power is increased but the selectivity is decreased, resulting in deeper extraction but a lower yield of raffinate (15). it appears from figure 10 that the yield percentage decreases as the extraction temperature increases but that effect is some what little in comparison with the effect of solvent to oil ratio. figure 11 shows the effect of increasing solvent to oil ratio on decreasing the raffinate yield percentage at various extraction temperatures. figure 10 effect of extraction temperature on raffinate yield at various solvent to oil ratio the effect of solvent extraction of light lubricating oil on viscosity index and chemical composition ijcpe vol.8 no.4 (december 2007) 8 figure 11 effect of solvent to oil ratio on raffinate yield at various extraction temperatures the effect of extraction temperature and solvent to oil ratio on raffinate sulfur content sulfur species are reactive and corrosive and can be reduced by solvent extraction process by removing the heteroaromatics which are typically multi-ring aromatics that contain one or more atoms of sulfur, oxygen or nitrogen (6). figure 12 shows the effect of extraction temperature on raffinate sulfur content at various solvent to oil ratio, while figure 13 shows the effect of solvent to oil ratio on raffinate sulfur content at various extraction temperatures. it obvious from figure 12 that the sulfur percentage in ra ffinate produced by solvent extraction decreases with increasing the extraction temperature for a given solvent to oil ratio. figure 13 shows that the increase in solvent to oil ratio has higher effect on decreasing the sulfur percentage of the raffinate obtained by solvent extraction compared with the effect of extraction temperature. figure 12 effect of extraction temperature on raffinate sulfur content at various solvent to oil ratio figure 13 effect of solvent to oil ratio on raffinate sulfur content at various extraction temperatures the effect of extraction temperature and solvent to oil ratio on other properties refractive index and density are a fundamental physical properties that can be used in conjunction with other properties to characterize the composition of lubricating oils (16, 17). the lower values of refractive index are associated with paraffins and higher values with aromatics (15). figure 14 shows the effect of increasing extraction temperature on decreasing the raffinate refractive index at various solvent to oil ratio, while figure15 shows the effect of increasing solvent to oil ratio on decreasing the raffinate refractive index at various extraction temperatures. it may be conclude that the most important factor affecting the reduction in raffinate refractive index is the solvent to oil ratio and that reflects the best quality of raffinate. figure 14 effect of extraction temperature on raffinate refractive index at various solvent to oil ratio abdul halim a.-k. mohammed et al ijcpe vol.8 no.4 (december 2007) 9 figure 15 effect of solvent to oil ratio on raffinate refractive index at various extraction temperatures in general, the density of raffinate produced from extraction decreases with increasing the extraction temperature or increasing the solvent to oil ratio and this is due to the extraction of aromatic materials which have the higher density among the hydrocarbons that presented in raw lubricating oils. figure 16 shows the effect of increasing the extraction temperature on decreasing the raffinate density at various solvent to oil ratio, while figure 17 shows the effect of increasing solvent to oil ratio on decreasing the raffinate density at various extraction temperature. figure 17 indicates that the increase in solvent to oil ratio for a given extraction temperature has hig her effect on decreasing the raffinate density compared with the effect of increasing the extraction temperature. figure 16 effect of extraction temperature on raffinate density at various solvent to oil ratio the color is important since it is readily observed by the customer (16). the color of a new oil depends on its degree of refining, and its content of aromatics (7). figure 17 effect of solvent to oil ratio on raffinate density at various extraction temperatures the effect of extraction temperature and solvent to oil ratio on hydrocarbon composition the qualities required for a lubricating oil base-stock are usually determine by measuring of either the product viscosity index or saturates content. the increase in raffinate viscosity index related to the reduction in naphthene-aromatic and polar aromatic content and the increase in saturates content in the produced raffinate (6). alternatively, the composition of hydrocarbons may be expressed in term of a carbon distribution, that is the percentage of the total number of carbon atoms that are present in aromatic ring structures (%ca), naphthene ring structures (%cn), and in paraffin chains (% cp) (18). in the present work the carbon distribution and structural group analysis of produced raffinate was calculated by the n -d-m method. figures 18 and 19 show the effect of increasing extraction temperature on decreasing the percentage of the total number of carbon atoms present in aromatic ring structures (%ca) and naphthene ring structures (%cn) of produced raffinate respectively at various solvent to oil ratio, while figure 20 shows the effect of increasing extraction temperature on increasing the percentage of the total number of carbon atoms present in paraffin chains (%cp) of produced raffinate at various solvent to oil ratio. figures 21 and 22 show the effect of increasing solvent to oil ratio on decreasing the percentage of the total number of carbon atoms present in aromatic ring structures (%ca) and naphthene ring structures (%cn) of produced raffinate, respectively, at various extraction temperatures, while figure 23 shows the effect of increasing solvent to oil ratio on increasing the percentage of the total number of carbon atoms present in paraffin chains (%cp) of produced raffinate at various extraction temperatures. it is obvious from figures 21, 22 and 23 that the solvent to oil ratio have the higher effect compared with the effect of extraction temperature shown in figures 18, 19 and 20. the effect of solvent extraction of light lubricating oil on viscosity index and chemical composition ijcpe vol.8 no.4 (december 2007) 10 by comparison the results of figures 18 -23 with those in figures 8 and 9, it obvious that the viscosity index increases with increase the percentage of the total number of carbon atoms present in paraffin chains and decrease the percentage of the total number of carbon atoms present in aromatic and naphth ene ring structures. figure 18 effect of extraction temperature on the percentage of the total number of carbon atoms present in aromatic ring structure (%ca ). figure 19 effect of extraction temperature on the percentage of the total number of carbon atoms present in napthene ring structure (%cn). figure 20 effect of extraction temperature on the percentage of the total number of carbon atoms present in paraffin chains(%cp). figure 21 effect of solvent to oil ration on the percentage of the total number of carbon atoms present in aromatic ring structure (%ca). s o l v e n t t o o i l r a t i o , w t / w t % c n 24 26 28 30 32 34 36 1 : 1 2 : 1 3 : 1 4 : 1 70 oc 80 oc 90 oc 100 oc 110 oc figure 22 effect of solvent to oil ration on the percentage of the total number of carbon atoms present in napthene ring structures (%cn). figure 23 effect of solvent to oil ration on the percentage of the total number of carbon atoms present in paraffin chains(%cp). the composition of complex petroleum fractions is often expressed in terms of the proportions of aromatic rings (ra), naphthene rings (rn) and paraffin chains (cp) that would comprise a hypothetical mean molecule (12). figures 24 and 25 show the effect of increasing the extraction temperature on the average number of aromatic abdul halim a.-k. mohammed et al ijcpe vol.8 no.4 (december 2007) 11 rings per molecule (ra) and the average number of naphthene rings per mo lecule (rn) of produced raffinate, respectively, at various solvent to oil ratio. figures 26 and 27 show the effect of increasing the solvent to oil ratio on the average number of aromatic rings per molecule (ra) and the average number of the naphthene rin gs per molecule (rn) of produced raffinate, respectively, at various extraction temperature. figure 24 effect of extraction temperature on the average number of aromatic rings per molecule, (ra). figure 25 effect of extraction temperature on the average number of napthene rings per molecule, (rn). figure 26 effect of solvent to oil ration on the average number of aromatic rings per molecule, (ra). figure 27 effect of solvent to oil ration on the average number of napthene rings per molecule, (rn). ternary phase diagram for extraction of lubricating oil with furfural at different temperatures ternary phase diagram, triangular coordinate, is used to represent the isothermal equilibrium data of threecomponent systems. in the present investigation, ternary liquid -liquid equilibrium data were obtained and three-component phase diagram were drawn for the system mixed-light lube oil fraction (40 stock) and furfural at different temperatures. figure 28 shows the effect of changing extraction temperature on the liquid -liquid equilibria of the system. figure 28 effect of extraction temperature on the liquidliquid equilibrium of mixedlight lube oil fraction (40 stock) and furfural system the effect of solvent extraction of light lubricating oil on viscosity index and chemical composition ijcpe vol.8 no.4 (december 2007) 12 conclusions 1. the viscosity index of lubricating oil fraction increases from 66 to 94.5 as a minimum by extraction at 70°c and 1:1 solvent to oil ratio and reaches 115.6 as a maximum by extraction at 110°c and 4:1 solvent to oil ratio. 2. the solvent to oil ratio has the higher influence on increasing the raffinate viscosity index and decreasing viscosity, density, refractive index, sulfur content, color, and yield. 3. the sulfur content of the raffinate decreases with increasing extraction temperature and solvent to oil ratio, the lower sulfur content obtained was 0.9983%wt at 110°c and 4:1 solvent to oil ratio. 4. the area under the bimodal curve which representing two liquid layers in the three component phase diagram decreases as the temperature of extraction increases. 5. the percentage of the total number of carbon atoms pres ent in aromatic and naphthene ring structures decreases while the percentage of the total number of carbon atoms present in paraffin chain increases with increasing extraction temperature and solvent to oil ratio. references 6. sequeira, a., sherman, p.b., j. v. and mc bride, e.o., “hydrocarbon processing”, vol.58, no.9, p. 155-160, 1979. 7. von fuchs, g.h., and anderson, a.p., “industrial and engineering chemistry”, vol. 29, no.3, p. 319-325, 1937. 8. baskara rao, b.k., “modern petroleum refinery processes”, 2nd ed., oxford and ibh publishing co., new delhi, 1990. 9. gary, j. h., “petroleum refining technology and economics”, 3rd ed., marcel dekker inc., new york, 1994. 10. kishore nadkarni, r.a., “guide to astm test method for the analysis of petroleum products and lubricants”, american society for testing and materials, west conshohocken, 2000. 11. lucas, a.g., “modern petroleum technology”, vol.2, john wiley and sons ltd, england, 2001. 12. denis, j., briant, j., and hipeaux, j.c., “lubricant properties analysis and testing”, editions technip, paris, 1997. 13. nelson, w.l, “petroleum refinery engineering”, 4th ed., mc graw-hill, inc., new york, 1958. 14. annual book of astm standards, vol. 05.01, 1994. 15. kalichevsky, v. a., and kobe, k. a., “petroleum refining with chemicals”, elsevier publishing company, london, 1956. 16. gruse, w. a., and stevens g.r., “chemical technology of petroleum”, 3rd ed., mc-graw hill, new york, 1960. 17. annual book of astm standards, vol. 05.02, 2000. 18. hunter, t.g., and nash, a.w., “industrial and engineering chemistry”, vol.27, no.7, p. 836-844, 1935. 19. kosters, w.c.g., “chemistry and industry”, vol.15, no.2, p. 220-223, 1977. 20. hobson, g.d., “modern petroleum technology” 4th ed., applied science publishers ltd, great britain, 1975. 21. allinson, j. p., “criteria for quality of petroleum products”, applied science publishers ltd, great britain, 1973. 22. http://en.wikipedia.org/wiki/furfural, 2006. 23. baskara rao, b.k., “modern petroleum refinery processes”, 2nd ed., oxford and ibh publishing co., new delhi, 1990. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.20 no.2 (june 2019) 17 – 22 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: hamzah abdalameer lafta , email: hamzaabdalameer75@gmail.com , name: mahmood k. h. al-mashhadani, email: mkh_control@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. effect of microwave treatment in graphite anode for microbial fuel cell and its application in biosensor hamzah abdalameer lafta and mahmood k. h. al-mashhadani college of engineering-university of baghdad/ baghdad, iraq abstract the electrode in the microbial fuel cell has a significant effect on cell performance. the treatment of the electrode is a crucial step to make the electrode surface more habitable for bacteria growth, thus, increases the power production as well as waste treatment. in the current study, two graphite electrodes were treated by a microwave. the first electrode was treated with 100w microwave energy, while the second one was treated with 600w microwave energy. there is a significant enhancement in the surface of the graphite anode after the pretreatment process. the results show an increase in the power density from 10 mw/m 2 to 15 mw/m 2 with 100w treatment and to 13.47 mw/m 2 with 600w treatment. an organic sensor was obtained for the same waste material used, where the sensitivity was weak, ranging from 100 mg/l for organic matter to 150 g /l. the sensor was used once again for each substance with better results. the sensitivity ranged from 25 g/l per liter to 150 g/l, while successful linearity has been gain. therefore, it can conclude that the microbial fuel cell with dual chamber can be designed for a biosensor with the available and cost-effective material. keywords: microbial fuel cell; biofuel cell; microwave treatment; electrochemical, biosensor received on 25/07/2018, accepted on 23/02/2019, published on 30/06/1029 https://doi.org/10.31699/ijcpe.2019.2.3 1introduction recently, renewable energy sources as an alternative to fossil fuels have drawn attention for many researchers. for example, bioenergy produced from microorganisms (such as microalgae ‎[1] ,‎[2] or by taking advantage of the presence of the microorganisms to generate electricity as in the microbial fuel cell. microbial fuel cell (mfc) is an electrochemical device that uses bacteria to generate electricity by oxidizing organic matter ‎[3], ‎[4]. the main role of the bacteria is to make a biofilm on the surface of the anode electrode. this biofilm will act as a catalyst to degrade the organic matter ‎[5]. using the microbial fuel cell at different applications; such as wastewater treatment and energy production, showed the need for a cost-effective reactor with better performance. the electrode for the microbial fuel cell has a great effect on the cell performance. electrode material takes the most concern of cell due to their cost or availability. the choice of the electrode depends mostly on how the bacteria grow on the electrode surface and construct the biofilm. carbon materials are commonly used in mfc because they are inexpensive and have excellent conductivity, chemical stability, biocompatibility, and large surface area. various carbon materials, including graphite ‎[6] graphite foam ‎[7] woven graphite, graphite felt ‎[8] reticulated vitreous carbon (rvc) ‎[9] carbon paper ‎[10] have been reported. changing the properties of the electrode can be achieved with a specific modification. different treatment and modification have been taken to alter the electrode surface properties especially conductivity and biocompatibility. the treatment with ammonia gas, as an example, increased the surface charge of the electrode and improved mfc performance ‎[11]. nanomaterials also take part in these modifications, such as the use of carbon nano-tube to decorate the anode of mfc and enhance the power generation ‎[12]. graphite decorated anode with au nanoparticles produces current densities up to 20-times higher than that produced from plain graphite anodes by shewanella oneidensis mr-1, while pd-decorated anodes were 0.5– 1.5 times higher than the original ‎[13]. wang ‎[14] modified a graphite electrode with a simple method of heat treatment in an oven that also enhances the electrode performance. the microwave technology was used in the laboratory for sample preparation and heating for different field of science. the materials which interact with microwaves to produce heat are called microwave absorbers including carbon material. the carbon-based material is good microwave absorber. thus, the microwave has been used for many processes, including the synthesis of different carbon materials (i.e., nanostructures, graphite, active carbons, polymers, etc.) ‎[15]. menéndez et al. ‎[15] show that the microwave effect on carbon-based material by modifying their physical and chemical properties. https://doi.org/10.31699/ijcpe.2019.2.3 h. a. lafta and m. k. h. al-mashhadani / iraqi journal of chemical and petroleum engineering 20,2 (2019) 17 22 81 until now, there is no single biosensor that meets each of these necessities yet. the biosensors demonstrate a couple of one of a kind sorts of common signs, including change of advancement case or change in light power. biosensors that use an electrochemical signal, for instance, present or potential is called electrochemical biosensors ‎[14]-‎[18]. the mfc-based biosensor is an electrochemical biosensor. in an mfc-based biosensor, microorganisms created on the anode catalyze the oxidation of regular material present in the inflow and electrons are made at the anode. an mfc meets various necessities of the perfect sensor. it can be used as an early alerting motion since it is sensitive to various portions. moreover, it can be low in cost, direct in operation and can screen incessantly. various diverse biosensors require a transducer and one of the upsides of an mfc is a transducer is not required. another favored outlook is using typically available microorganisms. no innately balanced infinitesimal living beings are required like the case in some unique sorts of biosensors ‎[19], ‎[20]. 2material and methods 2.1. electrodes two types of the electrode have been used in the experiment: 1graphite rods (5cm long and 0.5cm diameter) present in the dry cell were used as electrodes for the anode. they were removed carefully and cleaned from the substances stick on the electrode surface using sandpaper. the electrode was treated with a bunsen burner to remove any unwanted substances on the surface. any substances on the surface of the graphite anode may poison the bacteria and prevent the biofilm formation. the electrode was washed with distilled water before used in the mfc reactor. the electrode was attached with nichrome wire due to its ability to resist corrosion, which will prevent any corrosion inside the cell. 2carbon fiber was treated with 3m hcl for 24 hours and used for the cathode. 2.2. media the waste used in the experiment was collected from al-mansour municipalities department. the collected waste was taken and mixed with tap water and distilled water to ensure the necessary element for the bacteria and to increase the conductivity at 20 ᵒ c. 2.3. separator the separator used in the experiment consists of filter paper (dr. watts cat no. 501) placed between two supporting gaskets, the filter paper acts as a base to support the solidified solution from both sides. the solidified solution contains 5% agar by mass and 1 m nacl solution. the solution was mixed and heated with a microwave oven to melt the agar and the poured at both sides of the filter paper and let it solidify for a few minutes. the thickness of the separator was 4mm. this type of separator will prevent the crossover of material from the anode to cathode; also, it is much better than the long salt bridge. 2.4. microbial fuel cell assembly a u shape microbial fuel cell was assembled from two glasses fitting, as shown in fig. 1. the cathode side consists of di water and air bubbling tube from a small compressor to supply the cell with oxygen. three cells were made in the same way. therefore the only difference was the treated electrode. the cell consists of two glass tube were connected to make a u shape. between these two parts, a salt bridge consists of 1m nacl and 3 wt% agar as a solidifying agent. fig. 1. microbial fuel cell reactor 2.5. set up a. electrode treatment set up 100 ml of wastewater was used in each cell and the voltage was recorded using multimedia (holdpeak hp90epc multimetro digitalis). the two electrodes were treated with the energy of 100 w and 600 w for 10 min in conventional microwave oven equipped with vent for gas generation each was used in different cell and the third electrode was left without treatment to compare the results. in order to find the difference between the treated and non-treated electrode, a voltage-time curve and polarization curve were used the comparison purpose. this comparison approach was also used by cheng and logan ‎[11] for electrodes performance with and without ammonia gas treatment. in order to obtain the polarization curve, the external resistance was changed from 10 ω-100 kω, while the current was measured at a resistance (r) from the microbial fuel cell. this setup was carried out according to lafta, 2018 ‎[21]. h. a. lafta and m. k. h. al-mashhadani / iraqi journal of chemical and petroleum engineering 20,2 (2019) 17 22 81 b. microbial fuel cell biosensor using mixed culture 1a mfc was used with the treated anode and the modified salt bridge. the cell was left to work for 2 weeks until the voltage is stabilized and the anode is catalyzed by the bacteria. 2the anode from the previous cell was used in the new cell where a 3kω of external resistor was connected 33.100ml of the wastewater was poured into the new cell and 428 ml were put in biological oxygen demand (bod) bottle. 4the voltage was recorded for each hour in the cell as well as the bod device provides an hourly measure for the organic compound. c. mixed culture microbial fuel cell biosensor 1a mfc was used with the treated anode and the modified salt bridge. the cell was operated for 2 weeks until the voltage is stabilized, and the anode is catalyzed by the bacteria. 2the anode from the previous cell was washed with distilled water and used in a cell with sucrose as its fuel. the concentration of the sucrose was 150 mg /l. the cell also connected with a 5 kω the external resistor. 3voltage and the concentration of the sources were measured each hour. 3results and discussion 3.1. electrode treatment wastewater was added to mfc. the power output and voltage of mfc increased gradually due to the biological activity of microorganisms. fig. 2 shows the increase of voltage with time for three cells and represents the response of the bacteria in three different cases. fig. 2. voltage generation curve from the three cells the first one where the electrode is left untreated where the max voltage reached to 600 mv in fourth day, then, it started to decrease since the bacteria colonized not all the anode surface. as for the cell, where the anode treated with 100 w in the microwave shows a better response from the first day one up to the fourth day with keep increasing voltage above 600 mv. the reason for this increase was the anode surface that treated using the microwave. this method gave it the suitable surface property and the biocompatibility necessary [15] for more bacteria to inhabit the anode surface. when the anode was treated with 600 w, the initial response of the cell was the better (268 mv) on the first day. however, the increase in the voltage was slower, while it was less than the two other cells with max voltage in the fifth day (665 mv). the polarization curve of the fuel cell was measured to investigate the amount of maximum current that can be generated with voltage. more current produced by the cell means more bacteria present on the anode surface. and that will lead to getting a thicker biofilm with higher power production. the experimental data in fig.3 show the difference between all three cells. for the non-treated electrode at 0.00488 ma, the voltage was the highest than all other cells with a value of 488 mv. fig. 3. polarization curve for three cells however, this value and the voltage of other cells decreased as higher load (resistance) applied to the cell. at current value higher than 0.0284 ma, the other treated cells by the microwave method gave a better result. the highest current was 0.14 ma, but with a different voltage of all cell. this current, the non-treated cell has the lowest voltage of 14 mv. the 100w treated anode has 17mv at 0.14 ma, and the best performance was for the 600 w treated anode with 18mv at the highest current. the figure also shows that the treated cell with microwave has a higher potential difference between the two electrodes. since all the cells had the same cathode type, thus, the anode potential increased by the bacteria due to the microwave effect on the anode surface. fig. 4 shows the power density curve of the three cells that were taken when the cells reached a steady-state reading voltage by changing the external resistance. h. a. lafta and m. k. h. al-mashhadani / iraqi journal of chemical and petroleum engineering 20,2 (2019) 17 22 02 the 0 w anode was no treatment occurs which shows the maximum power of 10 mw/m 2 . for 100 w treatments, which shows a stable range of the maximum power possible of 15 mw/m 2 and for 600w, the power density was between the two other cells of 13.47 mw/m 2 . fig. 4. power density curve of the three cells (with 0 w, 100 w, 600 w) 3.2. mixed cutler biosensor for same wastewater the bod was measured for the same wastewater used in the biosensor and the relation was drawn as shown in fig. 5. the voltage from the cell was 60 mv simultaneously the bod value was 143 mg/l. the voltage continues to increase and the bacteria digest the organic material. the increase of the voltage has a linear relation with the bod value. at the first three hours, the voltage was changing in linear behavior with the bod value. after 3 hours the line deviated from its linearity, and after 4 hours the value of voltage was constant because the equilibrium state has been reached. despite the voltage after 4 hours was reached the equilibrium, the bod value continued to increase. this means that the response voltage of the cell cannot sense the organic compound concentration, thus, the sensor has reached its limit. at the first four hours, the measurement started to get narrow until the voltage stabilized for the cell, but, not for the bod value. this sign indicates the variety of the bio-sensing and it is correct for the bod base test because the bacteria outranged their linear growth. therefore, the sensing range was from 143 mg/l to 175 mg/l by using the growth procedure. fig. 5. the response of biological oxygen demand (bod) with voltage comparing the results with similar work done by sumaraj and ghangrekar ‎[22] with the use of cod analysis instead of bod was studied. their result was a linear relation with r 2 equal to 0.954, while the present results have r 2 (0.9977). moreover, the bod test was used to measure the biodegradable organic matter concentration. indeed, it gives a realistic amount of more organic matter that can be guessed by cod measurement. in addition, the microbes in the mfc degrade biodegradable organic matter. therefore, in measuring concentration they are in the same category while the cod measure organic and inorganic matter, as well as, the microbes in the mfc cannot degrade the inorganic matter. 3.3. mixed culture biosensor for sucrose for the cell that contains 150 g/l of sucrose, dropping the voltage was observed for the catalyzed anode, as shown in fig. 6. the external resistance used was 5 kω, the voltage at the beginning was recorded 125 mv. as the cell continues to operate the canalized layer of bacteria, the sucrose and the voltage was decreased with time as the sucrose decreasing. the decrease in voltage with time is linear in 4 hours. this period shows that the range of sucrose measure occurred in the first four hours only. after four hours, the voltage was 51 mv and after another hour, it was the same. it indicates that equilibrium is reached at the bacterial culture in the anode surface. fig. 6. voltage with the resistance (5kω) for the sucrose cell h. a. lafta and m. k. h. al-mashhadani / iraqi journal of chemical and petroleum engineering 20,2 (2019) 17 22 08 each hour, when the voltage measured the consternation of the sucrose also measure using spectroscopy technique as shown in table 1. table 1. microbial fuel cell biosensor voltage and sucrose concentration time(h) voltage (mv) absorbency (a) concentration (g/l) current (ma/cm 2 ) 0 125 0.107 150 19.44012 1 88 0.082 118.6893 13.68585 2 76 0.067 98.2683 11.8196 3 69 0.032 50.6193 10.73095 4 51 0.025 41.0895 7.931571 5 51 0.011 22.0299 7.931571 the sucrose concentration and the voltage were presented in fig. 7. a curve fitting for the data has been performing using microsoft excel 2013. the value of r 2 is close to 0.9, which indicate the accuracy of the biosensor. fig. 7. the sucrose concentration and the voltage response 4conclusions measurement and calculations of the performance of the fuel cell with the microwave treatment show great promise for higher power density. the results show the effect of the microwave on the graphite material and increasing the performance of the cell and the response voltage. the microwave reaches the micropore of the graphite and makes the necessary surface modification on the electrode for bacteria to inhabit the electrode with increase the area of biofilm formation and thus increase the power density. the modification that carried out on the cell in the present research increased the sensitivity and the accuracy of the biosensor. the sensing range of the waste was from 140 mg/l to 170 mg/l nearly the same range in the previous studies but with more accuracy. moreover, a successful high range of sucrose sensing has been achieved. nomenclature ma current mfc microbial fuel cell. p power in watt (w) r resistance in ohm v voltage references [1] al-mashhadani m. k. h and khudhair e. m. 2017. experimental study for commercial fertilizer npk (20:20:20+te n: p: k) in microalgae cultivation at different aeration periods. iraqi journal of chemical and petroleum engineering. 18, 99-110. [2] a. ibrahim and b. abdulmajeed, “biological coexistence of the microalgae – bacteria system in dairy wastewater using photo-bioreactor”, ijcpe, vol. 19, no. 3, pp. 1-9, sep. 2018. [3] slate, a. j., whitehead, k. a., brownson, d. a. c. and banks, c. e. 2019. microbial fuel cells: an overview of current technology. renewable and sustainable energy reviews, 101, 60-81. [4] hu, j., zhang, q., lee, d.-j. & ngo, h. h. 2018. feasible use of microbial fuel cells for pollution treatment. renewable energy, 129, 824-829. [5] logan, b., hamelers, b., rozendal, r., schröder, u., keller, j., freguia, s., aelterman, p., verstraete, w. and rabaey, k., 2006, microbial fuel cells: methodology and technology, environmental science and technology, 40(17), pp.5181-5192. [6] liu, h., ramnarayanan, r. and logan, b., 2004, production of electricity during wastewater treatment using a single chamber microbial fuel cell, environmental science and technology, 38(7), pp.2281-2285. [7] chaudhuri, s. and lovley, d. ,2003, electricity generation by direct oxidation of glucose in mediator-less microbial fuel cells, nature biotechnology, 21(10), pp.1229-1232. [8] ter heijne, a., hamelers, h., saakes, m. and buisman, c., 2008, performance of non-porous graphite and titanium-based anodes in microbial fuel cells, electrochimica acta, 53(18), pp.56975703. [9] kargi, f. and eker, s., 2007, electricity generation with simultaneous wastewater treatment by a microbial fuel cell (mfc) with cu and cu–au electrodes, journal of chemical technology and biotechnology, 82(7), pp.658-662. [10] liu, h. and logan, b., 2004, electricity generation using an air-cathode single chamber microbial fuel cell in the presence and absence of a proton exchange membrane, environmental science and technology, 38(14), pp.4040-4046. [11] cheng, s. and logan, b. ,2007, ammonia treatment of carbon cloth anodes to enhance power generation of microbial fuel cells, electrochemistry communications, 9(3), pp.492-496. http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/196 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/196 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/196 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/196 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/196 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/5 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/5 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/5 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/5 https://www.sciencedirect.com/science/article/pii/s1364032118306920 https://www.sciencedirect.com/science/article/pii/s1364032118306920 https://www.sciencedirect.com/science/article/pii/s1364032118306920 https://www.sciencedirect.com/science/article/pii/s1364032118306920 https://www.sciencedirect.com/science/article/pii/s0960148117300794 https://www.sciencedirect.com/science/article/pii/s0960148117300794 https://www.sciencedirect.com/science/article/pii/s0960148117300794 https://www.sciencedirect.com/science/article/pii/s0960852406004998 https://www.sciencedirect.com/science/article/pii/s0960852406004998 https://www.sciencedirect.com/science/article/pii/s0960852406004998 https://www.sciencedirect.com/science/article/pii/s0960852406004998 https://www.sciencedirect.com/science/article/pii/s0960852406004998 https://pubs.acs.org/doi/abs/10.1021/es034923g https://pubs.acs.org/doi/abs/10.1021/es034923g https://pubs.acs.org/doi/abs/10.1021/es034923g https://pubs.acs.org/doi/abs/10.1021/es034923g https://pubs.acs.org/doi/abs/10.1021/es034923g https://www.nature.com/articles/nbt867 https://www.nature.com/articles/nbt867 https://www.nature.com/articles/nbt867 https://www.nature.com/articles/nbt867 https://www.sciencedirect.com/science/article/pii/s0013468608004064 https://www.sciencedirect.com/science/article/pii/s0013468608004064 https://www.sciencedirect.com/science/article/pii/s0013468608004064 https://www.sciencedirect.com/science/article/pii/s0013468608004064 https://www.sciencedirect.com/science/article/pii/s0013468608004064 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.1723 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.1723 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.1723 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.1723 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.1723 https://pubs.acs.org/doi/abs/10.1021/es0499344 https://pubs.acs.org/doi/abs/10.1021/es0499344 https://pubs.acs.org/doi/abs/10.1021/es0499344 https://pubs.acs.org/doi/abs/10.1021/es0499344 https://pubs.acs.org/doi/abs/10.1021/es0499344 https://www.sciencedirect.com/science/article/pii/s138824810600467x https://www.sciencedirect.com/science/article/pii/s138824810600467x https://www.sciencedirect.com/science/article/pii/s138824810600467x https://www.sciencedirect.com/science/article/pii/s138824810600467x h. a. lafta and m. k. h. al-mashhadani / iraqi journal of chemical and petroleum engineering 20,2 (2019) 17 22 00 [12] sharma, t., mohanareddy, a., chandra, t. and ramaprabhu, s., 2008, development of carbon nanotubes and nanofluids based microbial fuel cell, international journal of hydrogen energy, 33(22), pp.6749-6754. [13] fan, y., xu, s., schaller, r., jiao, j., chaplen, f. and liu, h.,2011, nanoparticle decorated anodes for enhanced current generation in microbial electrochemical cells, biosensors and bioelectronics, 26(5), pp.1908-1912. [14] wang, x., cheng, s., feng, y., merrill, m., saito, t. and logan, b., 2009, use of carbon mesh anodes and the effect of different pretreatment methods on power production in microbial fuel cells, environmental science and technology, 43(17), pp.6870-6874. [15] menéndez, j., arenillas, a., fidalgo, b., fernández, y., zubizarreta, l., calvo, e. and bermúdez, j., 2010, microwave heating processes involving carbon materials, fuel processing technology, 91(1), pp.1-8. [16] su l, jia w, hou c, lei y., 2011, microbial biosensors: a review. biosens bioelectron 26:17881799. [17] d'souza sf., 2001, microbial biosensors, biosens bioelectron ,16:337-353. [18] lei y, chen w, mulchandani a., 2006, microbial biosensors. anal chim acta 568:200-210. [19] soares, a., guieysse, b., jefferson, b., cartmell, e. and lester, j.n., 2008. nonylphenol in the environment: a critical review on occurrence, fate, toxicity and treatment in wastewaters, environment international, 34(7), pp.1033-1049. [20] hasan j, goldbloom-helzner d, ichida a, rouse t, gibson m., 2005, technologies and techniques for early warning systems to monitor and evaluate drinking water quality, a state-of-the-art review usa environmental protection agency. [21] lafta h. a. 2018 "microbial fuel cell as a biosensor for domestic wastewater", thesis, baghdad university. [22] sumaraj, s. and ghangrekar, m.m., 2014. development of microbial fuel cell as biosensor for detection of organic matter of wastewater, recent research in science and technology, 6(1). الميكروبية وتطبيقاته في تأثير معالجة الموجات الدقيقة في أنود الجرافيت لخمية الوقود المستشعرات الحيوية الخالصة القطب في خمية الوقود الميكروبية له تأثير كبير عمى أداء الخمية الكمي. يعتبر عالج القطب عممية مهمة لجعل سطح القطب أكثر مالئمة لمبكتيريا وبالتالي زيادة إنتاج الطاقة وكذلك معالجة النفايات. تم معالجة اثنين من واط واآلخر تعامل مع 100ة الميكروويف قطب الجرافيت مع الميكروويف وتم عالج واحد منهم مع طاق واط طاقة الميكروويف. تم تحسين سطح األنود الجرافيت عند التعامل مع أفران الميكروويف. زادت كثافة 600 لى 100عند معالجة 2ميجاواط / م 15إلى 2ميجاواط / م 10الطاقة من وعند 2ميجاواط / م 13.47واط وا ل عمى مستشعر عضوي لنفس مواد النفايات المستخدمة ، حيث كانت الحساسية واط. وتم الحصو 600معالجة جم / لتر. المستشعر تم استخدامه مرة أخرى 150ممغم / لتر لممواد العضوية إلى 100ضعيفة ، تتراوح من ينما جم / لتر, ب 150جم / لتر لكل لتر إلى 25تراوحت مدة الحساسية من .لكل مادة وكانت النتيجة أفضل كان الخطي الناجح هو الكسب. لذالك ممكن االستنتاج بان الخمية الحيوية مع الغرفة المزدوجة ممكن ان تصميم كمتحسس حيوي بمواد رخيصة ومتوفرة. : خمية الوقود الحيوي, معالجة بالموجات الدقيقة ؛ الكهروكيميائية ، المستشعرات الحيويةلة ادالكممات ال https://www.sciencedirect.com/science/article/pii/s0360319908005387 https://www.sciencedirect.com/science/article/pii/s0360319908005387 https://www.sciencedirect.com/science/article/pii/s0360319908005387 https://www.sciencedirect.com/science/article/pii/s0360319908005387 https://www.sciencedirect.com/science/article/pii/s0360319908005387 https://www.sciencedirect.com/science/article/pii/s0956566310002459 https://www.sciencedirect.com/science/article/pii/s0956566310002459 https://www.sciencedirect.com/science/article/pii/s0956566310002459 https://www.sciencedirect.com/science/article/pii/s0956566310002459 https://www.sciencedirect.com/science/article/pii/s0956566310002459 https://pubs.acs.org/doi/abs/10.1021/es900997w https://pubs.acs.org/doi/abs/10.1021/es900997w https://pubs.acs.org/doi/abs/10.1021/es900997w https://pubs.acs.org/doi/abs/10.1021/es900997w https://pubs.acs.org/doi/abs/10.1021/es900997w https://pubs.acs.org/doi/abs/10.1021/es900997w https://www.sciencedirect.com/science/article/pii/s0378382009002513 https://www.sciencedirect.com/science/article/pii/s0378382009002513 https://www.sciencedirect.com/science/article/pii/s0378382009002513 https://www.sciencedirect.com/science/article/pii/s0378382009002513 https://www.sciencedirect.com/science/article/pii/s0378382009002513 https://www.sciencedirect.com/science/article/pii/s095656631000607x https://www.sciencedirect.com/science/article/pii/s095656631000607x https://www.sciencedirect.com/science/article/pii/s095656631000607x https://www.sciencedirect.com/science/article/pii/s0956566301001257 https://www.sciencedirect.com/science/article/pii/s0956566301001257 https://www.sciencedirect.com/science/article/pii/s000326700501977x https://www.sciencedirect.com/science/article/pii/s000326700501977x https://www.sciencedirect.com/science/article/pii/s0160412008000081 https://www.sciencedirect.com/science/article/pii/s0160412008000081 https://www.sciencedirect.com/science/article/pii/s0160412008000081 https://www.sciencedirect.com/science/article/pii/s0160412008000081 https://www.sciencedirect.com/science/article/pii/s0160412008000081 https://updatepublishing.com/journal/index.php/rrst/article/view/1190 https://updatepublishing.com/journal/index.php/rrst/article/view/1190 https://updatepublishing.com/journal/index.php/rrst/article/view/1190 https://updatepublishing.com/journal/index.php/rrst/article/view/1190 iraqi journal of chemical and petroleum engineering vol.17 no.3 (september 2016) 1131 issn: 1997-4884 using different surfactants to increase oil recovery of rumaila field (experimental work) talib a. salih, safaa hussain sahi and ahmed noori ghani al-dujaili petroleum engineering department, college of engineering, university of baghdad abstract enhanced oil recovery is used in many mature oil reservoirs to increase the oil recovery factor. surfactant flooding has recently gained interest again. to create micro emulsions at the interface between crude oil and water, surfactant flooding is the injection of surfactants (and co-surfactants) into the reservoir, thus achieving very low interfacial tension, which consequently assists mobilize the trapped oil. in this study a flooding system, which has been manufactured and described at high pressure. the flooding processes included oil, water and surfactants. 15 core holders has been prepared at first stage of the experiment and filled with washed sand grains 80-500 m and then packing the sand to obtain sand packs samples for experiment. it was found that the best rate for water injection was 1.2 pv. productively, while the optimum injection rate was 1.0 pv economically. the study observed that the cost of water injection in secondary recovery increased 700% when pv injected increased from 1.0 pv to 8.0 pv, while the recovery increased only about 8% (58.77 – 66.7%). the effects of concentration, salinity and temperature is also explored by examined many values of each parameter according to surface tension by using capillary rise method. it was found that the optimum conditions for surfactant flooding for sodium dodecyl sulfate (sds) 0.01 molar for concentration, 5500 p.p.m for salinity and 70 c for temperatures. these conditions was used to all kinds of surfactants that have been used in this study. the study results indicated that the best surfactant in both productively and economically was sds with maximum recovery about 90% for each secondary and tertiary recovery and the optimum injection volume for all surfactants 1.2 pv . another 12 core holders with fixed pore volume were prepared for the second stage of the experiment. at this stage the pore volume was approximately constant and the variation included different values of sds concentrations (0.1 and 0.001 molar) and different values of salinity (1000 p.p.m and 3000 p.p.m) and temperature equal to 90 c. each value for concentration was experimented with the two values of salinity which in result obtaining four flooding conditions. each condition was flooded by three injection rates (50, 120, 200 %). the results proved the results obtained from the first stage. university of baghdad college of engineering iraqi journal of chemical and petroleum engineering using different surfactants to increase oil recovery of rumaila field (experimental work) 12 ijcpe vol.17 no.3 (september 2016) -available online at: www.iasj.net introduction the department of energy u.s.a, specified the amount of oil produced worldwide is one third of the total oil available only. so, by using the eor techniques will be able to produce more oil as the demand increase while we have a shortage in the supply. over the last three decades a lot of research was took place in the field of enhanced oil recovery and since the eor methods have been developing. these techniques were applied on mature and depleted reservoirs and showed improved efficiency compared with primary and secondary recovery (water-flooding) [1]. water flooding method, started after first, 1964 published his patent to increase oil recovery [2]. us. ‘patent no. 3,302,713, discloses a surfactant which radically improves the economics of the surfactant water flooding process [3]. while the surfactant of [ahearn et al. 1967] has been shown to be an economical and effective means for petroleum recovery, it has been found to be susceptible to depletion within the formation as are most surfactants and particularly the sulfonate surfactants [4]. surface-active agents or “surfactants” have been proposed for addition to flood water for lowering interfacial tension between the water and the reservoir oil, thereby that’s will lead to increase the recovery of oil displaced by a water flooding. typical surfactants which have been selected for enhanced oil recovery include alkyl pyridium salts, sodium lauryl sulfate, certain sulfonates, glycosides, sodium oleate, and quaternary ammonia salts [5]. nowadays many mature reservoirs under water flood have decreasing production rates despite having 50-75 % of the original oil left in the reservoir. in such cases the surfactant flooding can increase the economic productivity [6]. as mentioned before , surfactants are added to decrease the interfacial tension (ift) between oil and water. co-surfactants are blended into the liquid surfactant solution in order to improve the properties of the surfactant solution. the co-surfactant either serves as a promoter or as an active agent in the blended surfactant solution to provide optimal conditions with respect to temperature, pressure and salinity. due to certain physical characteristics of the reservoir, such as adsorption to the rock and trapping of the fluid in the pore structure, considerable losses of the surfactant may occur [7,1]. surfactant flooding is one of the three main chemical flooding processes which include polymer flooding, surfactant–polymer flooding and alkaline– surfactant–polymer (asp) flooding. addition of surfactant to the polymer formulation may, under very specific circumstances, reduce oilwater interfacial tension to almost zero displacing trapped residual oil [8]. the results of the core floods for iglauer et al. (2010) [9] which indicated a good oil recovery by surfactant flooding even at high salinities. pawga et al. (2010) [10] made a comparative study of different eor methods to estimate the best method economically. different eor methods have been studied and understood as a technical part of eit norne village. gholamzadeh et al. (2012) [11] discussed surfactant injection method in an oil-wet, dual-porosity model , concluded that the injection might not be effective. liang xu (2013) [12] research found that capillary pressure inside pore spaces, was not straightforward to predict or correlated to the performance of the surfactant that to be used during fracturing. ma, (2013) [13] provided an in depth http://www.iasj.net/ talib a. salih, safaa hussain sahi and ahmed noori ghani al-dujaili -available online at: www.iasj.net ijcpe vol.17 no.3 (september 2016) 13 understanding of transport of surfactant and foam through porous media using a combination of laboratory experiments and numerical simulations. in conclusion, thesis provides new findings in surfactant adsorption onto mineral surfaces, in the methodology to estimate foam parameters for reservoir simulation, and in micro-model observations of foam flow through porous media. habibi et al. (2014) [14] investigated the effect of different aging time and temperature on wettability alteration with exact soaking time in order to find the optimum condition. iglauer et al. (2014) [15] imaged a sandstone plug at connate water saturation, residual water flood saturation, surfactant flood saturation and polymer flood saturation in 3d at high resolution micrometer level, found that the water flood was quite efficient in terms of oil recovery and the polymer flood as well. nguyen et al. (2014) [16] presented a comprehensive evaluation of phase behaviors of alkaline / surfactant / polymer (asp) systems. the experimental results proved that the phase behavior of mixed-surfactant solutions (singleand double-tail anionic surfactants) would be better than the one of single surfactant. these mixtures were also more compatible with polymer, and adjusted optimum salinity to the reservoir brine. they next examined the role of alkalis in asp process. the study showed that sodium metaborate is the best choice. sun et al. (2014) [17] showed that 0.4 wt% ios2024 with 1 wt% iaa can provide ultra-low ift of 10 −3 mn/m at around 3000–4000 mg/l total dissolved solids, but at that salinity range the surfactant retention is very high. the search for an optimum surfactant formulation has to consider solution properties and retention in addition to the low ift. the following points are investigated in this work: 1. identify the properties of sand packs which will use in the experiment by the calculation bulk and pore volume , porosity and permeability . 2. study of the chemical reactions, which cause the loss of surfactant and the determination of the effect of water salinity (formation water) on its behavior, required the knowledge of the physical and chemical properties of the surfactant. 3. study of all factors and properties that effected on oil recovery which includes pore volume of the injected water for secondary recovery and surfactant for tertiary recovery and the effect of surfactant concentration, salinity and temperatures on surface tension values. 4. study of the effect of different displacement processes (water and surfactant flooding) under reservoir conditions (pressure and temperature). 5. check the best conditions for secondary recovery and eor which will effect on oil recovery (concentration, salinity and temperature). 6. identification of the production and economical limit of the injection process. 7. comparison of three kinds of surfactant (anionic, nonionic and cationic) in both economically and productively to select best surfactant kind in eor process in rumaila field. experimental work three types of surfactants were used to increase oil recovery, there were (sds, criton x100 and ctab) and the effects of concentration, salinity and temperature on the surface tension have been measured. porosity, http://www.iasj.net/ https://www.onepetro.org/search?q=dc_creator%3a%28%22heidari%2c+mohammad+a%22%29 using different surfactants to increase oil recovery of rumaila field (experimental work) 14 ijcpe vol.17 no.3 (september 2016) -available online at: www.iasj.net permeability and saturation measured also. water flooding have been done in first stage and oil recovery factor % recorded, followed by surfactant flooding. finally the oil recovery factor tabulated and plotted. materials 1. fluids 1.1. crude oil the crude oil used in the research have been taken from rumaila reservoir in the south of iraq and provided by al– dura refinery. the physical properties of the crude oil at 30 °c was shown in table 1 [18]. table 1: physical properties of the crude oil at 30°c temp., °c 30 specific gravity 0.879 api 29.47 kinematic viscosity, c.st 15.314 viscosity, c.p 13.461 1.2. water water used in the experiment for flooding process and preparation of surfactant solutions. density of the water used in the study was 1 gm/ cm 3 at 30 °c and the salinity was 500 p.p.m which calculated in the laboratory of civil engineering and water resources dept. / kufa university. 2. surfactant three types of surfactants used in this study in different concentrations. 2.1. anionic surfactant sodium dodecyl sulfate (sds) produced by alpha chemika company [19] used as anionic surfactant. figure 1 shows the chemical formula of this surfactant. fig. 1: sodium dodecyl sulfate and chemical structure 2.2. nonionic surfactant poly(oxy-1,2-ethanediyl), α-[4-(1,1,3,3 tetramethylbutyl)phenyl]-ω-hydroxy (triton x100) produced by central drug house company (cdh) under trade name (criton) [20] have been used as nonionic surfactant. figure 2 shows the chemical formula of the criton x 100. fig. 2: chemical formula of criton x 100 2.3. cationic surfactants hexa cetyl trimethyl ammonium bromide (ctab) produced by scr company used as cationic surfactant. [21] figure 3. fig. 3: chemical formula for ctab 3. sand sand has been used to prepare the sand pack with size distribution of 80 to 500 μm. 4. salts sodium chloride 99.975% has been used in the salinity experiment. http://www.iasj.net/ talib a. salih, safaa hussain sahi and ahmed noori ghani al-dujaili -available online at: www.iasj.net ijcpe vol.17 no.3 (september 2016) 15 system description the system used in this work consists of: 1. reservoir tank and accessories reservoir tank was made from carbon steel plates (6 mm thickness) in order to bear high pressure. this device contains also two vents , the first on the top of the tank with gate valve (inlet) to fill the tank by either water , oil or surfactant , and the second vent to ensure the filling of the tank with a reinforcement rubber pipe connected directly with high pressure co2 container. all the welding works were done by argon – tungsten in order to resist the high pressures. a schematic diagram of the part a including reservoir tank and all accessories is given in figure 4. fig. 4: sketch of flooding device the reservoir tank also have outlet vent consist of a 1/2" pipe, check valve to keep the liquid in the desired direction and also keeping on the pressure at the required value, gate valve to close this part after all liquid was pumped. the system also provided with a pressure gage to monitoring the pressure at the desired value. the end of the reservoir tank system (part a) was provided by 1.5" net to connect this part with the part b (sample system). also see figure 5. fig. 5: flooding device 2. core holder and water bath part b (core holder) consists of a double-tube high-pressure reinforcement rubber has an internal diameter of 1.5" connects with part a according to the base of the nut with the dentate part on one hand, and with a core holder in other hand, which consists of a pipe has an external diameter of 1.5" (38 mm) and internal diameter of (30 mm), core holder was made of anticorrosion stainless steel (grade 316) welded with pipe bushings (1.5") at the ends of the pipe. also it provided with very fine sieve welded inside the pipe to prevent movement of sand pack or sand grains along the pipes. figure 5 and 6. fig. 6: core holders http://www.iasj.net/ using different surfactants to increase oil recovery of rumaila field (experimental work) 16 ijcpe vol.17 no.3 (september 2016) -available online at: www.iasj.net the sample model also contain an open tank made from carbon steel gage (4 mm thickness), the dimensions of the tank (30 cm length, 20cm height and 15 cm width). the tank filled with water to use as a water bath to control the desired temperature in the experiment by providing an electric heater and thermostat. 3. collection section collection section made to connect with sample model to receive the fluid output of the injection process, then accumulation to measure the amount of fluid that has been obtained from the injection process. figure 4 and 5. the apparatuses used in the experiment were: a -fluid injection system during the experiments a co2 2000 psi bottle used to displace fluids in the sand pack. bcheck valve used to provide high pressure for injection. the check valve was used to move the fluid forward only and compact the contained fluid. cheater for heating the injected surfactant solution a heater placed on route. over this heater, a vessel containing a high boiling point material have been placed. dpressure differential gauge used to measure the pressure drop along the sand pack with 3000 psi as a maximum reading. esteel pipes, rubber reinforcement high pressure pipes the design of the system made to simulate "chemical flooding under reservoir conditions device" which is not available in iraq in the time of the experiment. a schematic diagram of the system is given in figure 4 and 5. experimental procedure 1. sand pack preparation silica grains with size distribution of 80 to 500 μm were used for preparing sand pack to obtain a homogeneous model with appropriate permeability. the silica’s seeds strew into the core holder after washing. screen and very tiny mesh were installed at the inlet and outlet of core holder to prevent removal of silica. 2. sand sieving and cleaning the sand was sieved and the 80-500 μm sized sand was taken for the experiments. the sand was cleaned firstly by thorough water washing to ensure removing the undesired salts. the cleaned sand was then dried. porosity measurement in this work the weight method was used to determine porosity. in this method the sand pack was measured in dry state initially, then it was saturated with water and the mass was measured again. the difference between two measured mass was equivalent to the mass of water which was saturating the sand pack. so the pore volume of saturated water can be calculated regards to water density (usually 1 gm/cm 3 ). with distinguishes of bulk volume, the porosity can be determined using eq. 1 . the porosity measurements of all sand pack samples have been listed in appendix a.1. …(1) permeability measurement the sand pack permeability was measured with oil after porosity measurement . the measurement was based on darcy's law which can be rearranged as the following equation : …(2) where: q = flow rate in cm 3 /sec  = viscosity of the fluid in c.p a = cross-sectional area of the sand pack in cm 2 http://www.iasj.net/ talib a. salih, safaa hussain sahi and ahmed noori ghani al-dujaili -available online at: www.iasj.net ijcpe vol.17 no.3 (september 2016) 17 k = permeability in darcy p = the pressure drop along the sand pack in atm. l = length of the sand pack in cm the flow rate and pressure values for each sand pack which used to calculate the permeability explained in detail in appendix a.2. the properties of sand pack shown in table 2. table 2: sand pack overall properties property (unit) sand pack core diameter (cm) 3 core height (cm) 15 bulk volume ( cm 3 ) 106.02875 porosity (%) 33.859 35.84 permeability (m.d) 848 after the permeability has been calculated, the samples weighted again to obtain the mass of oil that saturated the sand pack. the density value was known, so the volume of oil saturated was calculated also as in appendix a.3. emulsion preparation the emulsion was prepared in (1000 ml) glass prescription bottles. core flooding experiments experiments have been carried out on a conventional sand pack and in the following orders: 1. crude oil flooding after sand pack preparations, the oil saturated sand pack at presence of irreducible water under variable conditions of flow rates and pressures (temperature was constant at room temperature). first, twelve experiments have been done then core holder for each experiment weighted to calculate the mass of oil in the sand pack, because the density of the oil known (table 2), so it's volume was calculated for each sample as in the appendix a.3. all parts of the system and beakers were cleaned by detergent and water and dried by compressed air after any stage of flooding. 2. water flooding after all sand packs flooded by oil flooding, the second stage was water flooding. the experiment based on variable injected ratios according to basic pore volume of the sand pack (106.02875 cm 3 ). appendix a.4. then the economical cost have been checked for each flooding ratio to estimate the best economical value of injected ratio in secondary recovery. 3. surfactant solutions four solutions prepared for sds surfactant according to molecular weight (288.38) to specified the optimum conditions for surfactant flooding. the preparation based on water volume (1000 cm 3 ). then the surface tension has been calculated in the following conditions: 1. surface tension for sds solution in different concentrations the surface tension of a liquid is an internal pressure caused by the attraction of molecules below the surface for those at the surface of a liquid. the surface tension (or interfacial tension if the interface is not a surface) determines the tendency for surfaces to establish contact with one another [22]. the capillary rise method have been used to determine the surface tension of sds solution. (figure 7) first: the densities of sds solution in different concentrations were calculated and tabled. then the capillary rise method used to investigate the surfactant solution ability to reduce the surface tension by using the following formula [23]:           21 r 1 r 1 g 2 ρδh γ …( 3 ) http://www.iasj.net/ using different surfactants to increase oil recovery of rumaila field (experimental work) 18 ijcpe vol.17 no.3 (september 2016) -available online at: www.iasj.net where:  = surface tension ( dyne / cm )  = density ( gm / cm 3 ) h = h1 – h2 which h1 , h2 the height of solution in capillary tubes in cm g = gravity acceleration = 980 cm / sec 2 r1 , r2 = radius of capillary tubes in cm fig. 7: capillary rise method 0.063 and 0.3325 cm radius for capillary tubes were used in the experiment. 2. calculation of surface tension for sds solution in different salinity ratios four weights of nacl were selected to prepare the solutions with sds (10 -2 molar) , water (salinity 500 p.p.m) and (500, 1000, 2500, 5000 p.p.m) of nacl and in the same way the surface tension was calculated for each solution. 3. calculation of surface tension for sds solution in different temperatures the effect of temperature has been studied to select the optimum temperature for surfactants flooding. the solution selected which depended on the previous experiments (concentration, salinity) contains sds solution in concentration equal to (10 -2 molar) and 5500 p.p.m of total salinity and in the same way the surface tension has been calculated for the solution in different temperatures (40, 50 , 60 and 70 c). surfactant flooding 1. sds flooding (anionic surfactant) first, five flooding processes have been done for sds solution under pressure equal to 1000 psi and 2 cc/ sec for flow rate. these flooding processes represented injection ratios of 50%, 75%, 100%, 120% and 200% according to pore volume. 2. criton x100 flooding (nonionic surfactant) criton x100 solutions at the same conditions and under pressure equal to 1000 psi and 2 cc/ sec as flow rate injected for the same five pv% injected in sds flooding. (appendix a.8). 3. sds flooding under different conditions at constant pore volume to study the effects of different conditions at fixed pore volume, twelve tests have been carried out, but at this tests sand packs with pore volume (37.2 cm 3 ) have been prepared. the pore volumes have been tabled in appendix a.10. also the remaining oil after secondary recovery has been measured (appendix a.10). three pv injected % considered according to the original pore volume which were 50, 120, 200 % respectively. four different conditions have been adopted for sds surfactant as follow: 1sds concentration equal to 0.1 molar , 3000 p.p.m for salinity and 90 c for temperature. 2sds concentration equal to 0.1 molar, 1000 p.p.m for salinity and 90 c for temperature. 3sds concentration equal to 0.001 molar, 3000 p.p.m for salinity and 90 c for temperature. 4sds concentration equal to 0.001 molar, 1000 p.p.m for salinity and 90 c for temperature. the pore volume was constant and the oil volume before sds flooding was approximately constant (between 16.4 – 16.48 cm 3 ).  http://www.iasj.net/ talib a. salih, safaa hussain sahi and ahmed noori ghani al-dujaili -available online at: www.iasj.net ijcpe vol.17 no.3 (september 2016) 19 results and discussions for each core holder the inside radius equal to 1.5 cm and height equal to 15 cm, so the volume of the core holder which also represent the bulk volume of sand pack for sand pack no.1 will be: volume of all sand pack (bulk volume) =  r2 h = 3.1416 × 1.52 × 15 = 106.02875 cm 3 . the calculations of porosity for all sand packs have been tabled in appendix a.1. the calculation of porosity showed a range (33.86 % to 35.84%). according to safarzadeh et al (2011) [24], the sand pack porosity was approximately 30% as shown in figure 8. fig. 8: comparison of porosity values in current study with previous studies permeability measurement pressure drops at different flow rates were measured as in table 3. then qμ/a was plotted versus δp/l. a straight line which was crossed through the origin can be fitted to the data. the slope of the line represents the permeability of the sand pack. there may have been an experimental artifact in the data, if the data deviate significantly or systematically from the linear trend. eight core holders were used in this stage of research, the value of 1500 psi was neglected (table 4), (figure 9 ), appendix a.2. table 3: values of pressure and flow rates in oil flooding core holder no. p (psi) q ( cm 3 /sec) 1 250 0.879 2 450 1.289 3 500 1.367 4 650 1.465 5 700 1.742 6 820 1.987 7 1000 2.259 8 1500 3.180 table 4: values of permeability by darcy equation (2) q /a p /l k m.d (calculated) 1.673917 1.133787 1476 2.454697 2.040816 1203 2.603236 2.267574 1148 2.789861 2.947846 946 3.317364 3.174603 1045 3.783928 3.718821 1017 4.301909 4.535147 948 6.055808 6.802721 890 fig. 9: calculation of permeability by using darcy's equation k avg. = slope = 848 m.d the following relationships were used for conversion the units to darcy's units. …(4) http://www.iasj.net/ using different surfactants to increase oil recovery of rumaila field (experimental work) 20 ijcpe vol.17 no.3 (september 2016) -available online at: www.iasj.net where: cst = viscosity in cente stock cp= viscosity in cente poise sg= specific gravity pressure 1 pound per square inch = 0.068 atm. the comparison between the permeability obtained from current study and previous studies shown in figure 10. fig. 10: permeability (m.d) comparison between current study and previous studies water flooding many injection ratios were experimented which represented 50%, 75%, 90%, 100%, 120%, 200%, 400%, 600% and 800% of the pore volume at flow rate 5 cc/sec for all pv ratios to check the best value of pv which match with economical limits, then the oil and water for each sand pack from secondary recovery process collected and separated, the oil volumes calculated, so the recovery percent became available to estimate as in appendix a.4 and figure 11. the water flooding results showed minimum recovery factor % was 39.892% at injection ratio 50% of pore volume and maximum value 66.7% at 800%. the difference may be due to the difference in porosity and permeability of the sand packs that prepared and also to the difference in oil properties. figure 12. fig. 11: secondary recovery factor % according to of pv injected % of pore volume according to results the p.v injected at 120% for the pore volume was the best volume due to slightly changes in oil recovery factor with highly costs when the p.v injected have been increased more than 120%. a second oil and water flooding processes for seven core holders were done in the same procedure. (appendixes a.6, a.7 ). fig. 12: comparison for secondary recovery factor % between the present study and previous studies schaefer, 2012 [29], estimated the water injection's price for secondary recovery (5 10 $/bbl), so according 848 350 303 0 100 200 300 400 500 600 700 800 900 permeability ( m.d ) current study mehdi et al. (2013) safarzade h et al ( 2011) http://www.iasj.net/ talib a. salih, safaa hussain sahi and ahmed noori ghani al-dujaili -available online at: www.iasj.net ijcpe vol.17 no.3 (september 2016) 21 to table 5 and figure 13 for water injection cost 5 $ / bbl, the pv injected for more than 100% for oil pv after primary recovery approximately double increased and that must be considered economically and will be useful in determination the start point of the tertiary recovery. table 5: % of increase in oil recovery factor according to % increase of pv injected calculated to every 100 bbl of oil pv injected % recovery factor% additional cost $/ bbl oil 50% 39.892 6.267 75 % 50.415 7.438 90 % 55.714 8.077 100 % 58.77 8.508 120% 60.2% 9.967 200 % 61.05 16.38 400% 63.82 31.34 600% 65.5 45.8 800% 66.7 59.97 according to results the p.v injected at 100% for the pore volume was the best volume due to economical limits. fig. 13: additional cost in $/bbl according to pv injected surfactant solutions table 6 show the preparation of four sds solutions in different concentrations and it's densities in room temperature 30 c listed in table 7. table 6: preparation of four sds solutions sds weight gm resulting solution molar 28.838 10 -1 2.8838 10 -2 0.28838 10 -3 0.028838 10 -4 table 7: density of sds solutions concentration of sds solution (molar) density (gm / cm 3 ) 10 -1 0.9903 10 -2 0.9822 10 -3 0.9702 10 -4 0.9552 calculation of surface tension 1. for sds solution at different concentrations the results obtained from capillary rise method for four different sds concentrations showed that the best concentration was 0.01 molar as in table 8. table 8: surface tension values by capillary rise method sds conc. in molar density gm / cm 3 h1 cm h2 cm h cm  dyne/cm 10 -1 0.9903 2.179 1.55 0.629 23.724 10 -2 0.9822 4.80 4.289 0.611 22.856 10 -3 0.9702 4.513 3.8853 0.6277 23.194 10 -4 0.9552 5.232 4.59 0.642 23.356 the concentration of 10 -2 molar selected to check the effect of salinity. figure 14. fig. 14: effect of sds concentration on surface tension values 23.724 22.856 23.19423.356 22 23 24 25 26 27 28 0.0001 0.001 0.01 0.1 1 sds concentration in molar s u r f a c e t e n s io n d y n e / c m http://www.iasj.net/ using different surfactants to increase oil recovery of rumaila field (experimental work) 22 ijcpe vol.17 no.3 (september 2016) -available online at: www.iasj.net wang et al. 2013 experimented the surface tension of either fresh and produced water with three types of polymer surfactant and they found a range of surface tension of fresh water between 22.15 and 23.14 dyne /cm as for a concentration of polymer between 200 -1000 mg/ l [30]. raney et al. 2011 found the optimum asp concentration to obtained the lower interfacial tension was 10 -3 molar [31]. 2. calculations of surface tension for sds solution in different salinity values the effect of salinity has been represented by different nacl values in p.p.m have been experimented to select the best salinity according to lower surface tension values (table 9). table 9: surface tension values for sds solution + nacl water salinity p.p.m nacl p.p.m density gm/cm 3 h cm  dyne/cm  variation dyne/cm according to reference value 22.856 5 0 0 500 0.9820 0.705 26.368 + 3.512 1000 0.9817 0.665 24.864 + 2.008 2500 0.9811 0.59 22.0462 0.8098 5000 0.9805 0.52 19.4187 3.4373 the result showed that the sds surfactant with water in concentration (0.01 molar) and with addition of 5000 p.p.m for nacl (5500 p.p.m salinity in total) gave the lower surface tension in comparison with the other conditions that have been experimented. figure 15. fig. 15: effect of nacl concentration on surface tension values liu, (2008) [32] resulted that the optimum salinity for asp flooding was 4000 p.p.m. while mwangi, (2010) indicated that the best salinity for surfactant flooding was 4000 p.p.m. nasralla et al. (2011) [33] took a best results of oil recovery by using water with a salinity 5000 p.p.m, while samanta et al. (2011) [26] results showed a surface tension range for sds surfactant with addition of phpa polymer and nacl between 32 dyne / cm at 0 p.p.m and 34 dyne/ cm at 2000 p.p.m. the comparison of salinity values between current study and previous studies showed a significant convergence of salinity used as the best condition for surfactant solution as shown in figure 16. fig. 16: a comparison of the optimum salinity between current study and previous studies 26.368 19.4187 22.0462 24.864 15 17 19 21 23 25 27 1000 2000 3000 4000 5000 6000 nacl concentration in p.p.m s u rf a c e t e n si o n d y n e / c m http://www.iasj.net/ talib a. salih, safaa hussain sahi and ahmed noori ghani al-dujaili -available online at: www.iasj.net ijcpe vol.17 no.3 (september 2016) 23 3. calculation of surface tension for sds solution in different temperatures the effect of temperature has been studied by examining different temperatures for sds solution in concentration equal to 0.01 molar and 5500 p.p.m for salinity. the result as shown in table 10. the result showed that the sds surfactant with water in concentration (0.01 molar) and with addition of 5500 p.p.m for salinity in 70 c represented best result in order to the less surface tension in comparison with the other temperatures that have been experimented. as shown in figure 17. table 10: surface tension values for sds solution in different temperatures temp. c h1 cm h2 cm h cm  dyne/cm  variation dyne/cm according to value 19.4187 30 2.02 1.50 0.52 19.4187 0 40 1.995 1.51 0.485 18.1117 1.307 50 1.863 1.386 0.477 17.813 1.6057 60 1.821 1.363 0.468 17.477 1.942 70 1.804 1.355 0.459 17.141 2.2777 thornton, (1974) [34] indicated that for sds solution (0.1 molar) and 5000 p.p.m, the best temperature for minimum surface tension was 80 °c. no specific change in surface tension value when temperature was varied from 80 °c to 70 °c. tang et al. (2006) [35] found the optimum temperature for sds solution at 90 °c. for sds solution between 0.005 to 0.01 molar at 70 °c the surface tension differences could not been noticed. fig. 17: surface tension values in different temperatures for sds solution safarzadeh et al (2011) [17] and mehdi et al. (2013) [15] used sand pack model for surfactant flooding at 70 °c. the results as shown in figure 18 indicated a clear convergence in temperatures used in best condition of sds solution between current study and previous studies. fig. 18: a comparison of the optimum temperatures for different studies surfactant flooding the properties of solution selected for surfactant flooding listed in table 11. table 11: surfactant solution's properties property ( unit) sand pack concentration (mol/l) 0.01 salinity (p.p.m) 5500 test temp. 70c 17.1410 17.477017.8130 18.1117 19.4187 15 16 17 18 19 20 21 22 23 24 25 30 35 40 45 50 55 60 65 70 75 temp. of sds solution in c s u r f a c e t e n s i o n d y n e / c m 70 70 80 70 70 90 0 10 20 30 40 50 60 70 80 90 100 optimum temp degree c current study thornton 1974 ziegler 1981[27] tang 2006 safarzade h 2011 mehdi 2013 http://www.iasj.net/ using different surfactants to increase oil recovery of rumaila field (experimental work) 24 ijcpe vol.17 no.3 (september 2016) -available online at: www.iasj.net 1. sds flooding (anionic surfactant) flooding processes represented injection ratios of 50%, 75% , 100%, 120% and 200% according to pore volume indicated that 67.58% of oil volume has been recovered after sds flooding according to oil volume remained in the pv with injection ratio 120% and 89.4% could be recovered after both secondary and tertiary flooding at the same injection ratio. the results have been tabled in appendix a.5 and represented in figure 19. fig. 19: sds recovery factor % for % of pv injected according to safarzadeh et al (2014) [37], the rf% was 87% for sds flooding at the same circumstances. figure 20. according to figure 19 the best sds recovery economically and quantitatively was 120% pv injected. the result also indicated to semi match for recovery factor % result obtained at pv injected rates (50% 100%) between water flooding and sds flooding. fig. 20: % oil recovery factor comparison for different researches 2. criton x100 flooding (nonionic surfactant) the results of criton x100 flooding showed that at 120% pv, the rf% was 84.14 % by both secondary and tertiary recovery, while 85.6% recovered at 200% pv ( figure 21). fig. 21: criton x100 recovery factor % for % of pv injected 3. ctab flooding (cationic surfactant) the results clarified that about 85% of oil has been recovered at 120% pv by both secondary and tertiary recovery, while 86% recovered at 200% pv. the result shown in figure 22. 0 75.23% 81.80% 89.40% 00 17.98% 89.93% 88.30% 67.26% 66.70% 65.50% 63.82% 60.60% 22.67% 22.70% 22.80% 14.63% 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 0 0.25 0.5 0.75 1 1.25 1.5 1.75 2 pv injected % of pore volume. r e c o v e ry f a c to r % total oil recovery factor % ( secondary + tertiary ) secondary recovery factor % sds recovery factor % http://www.iasj.net/ talib a. salih, safaa hussain sahi and ahmed noori ghani al-dujaili -available online at: www.iasj.net ijcpe vol.17 no.3 (september 2016) 25 fig. 22: ctab recovery factor % for % of pv injected comparison between surfactants according to rf % the results obtained in this study distinct in clearly image that the anionic surfactant sds was the best surfactant according to productivity as in figure 23. the results as represented in figure 16 demonstrated that oil recovery factor % in criton x100 and ctab flooding were very closely at pv injected ≥ 75%. fig. 23: comparison of rf % according to the surfactant type comparison between surfactants economically based on the international price , the prices of sds , criton x100 and ctab in recent time is 1000-1300 us $/ metric tons, 63 us $/lit and 10005000 us $/ metric tons respectively. according to mathematical relations:  the total cost of one barrel of sds is about 0.6$.  for criton x100, 100.1$ /bbl  for ctab, 2.9$ /bbl. and according to the difficulty of handling for criton x100 because the liquid form , expensive cost and low recovery in comparison with sds and also because of the approximate similarity between criton x100 and ctab, it's prefer to use sds in surfactant flooding. sds flooding under different conditions at constant pore volume the results of 15 flooding processes matched the result of the study when the surface tension values have been taken in consideration to determine the optimum conditions for sds flooding to ensure maximum oil recovery. figure 24. comparison between rf % obtained under different conditions at constant oil pv and 90 c the results shows in clearly image that the best conditions for surfactant flooding as adopted before depending on the surface tension indicator. the overall comparison between all conditions of experiments plotted in figure 25. 0 59.63% 75.00% 84.96% 0 40.20% 85.92%83.60% 60.38% 50.50% 58.32% 60.20% 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 0 0.25 0.5 0.75 1 1.25 1.5 1.75 2 2.25 pv injected % of pore volume. r e c o v e r y f a c t o r % total oil recovery factor % (secondary + tertiary ) secondary recovery factor % 50% 55% 60% 65% 70% 75% 80% 85% 90% 95% 0.50 0.75 1.00 1.25 1.50 1.75 2.00 pv injected % of pore volume. r e c o v e r y f a c t o r % sds recovery factor % criton x100 recovery factor % ctab recovery factor % http://www.iasj.net/ using different surfactants to increase oil recovery of rumaila field (experimental work) 26 ijcpe vol.17 no.3 (september 2016) -available online at: www.iasj.net fig. 24: rf % of sds at different conditions fig. 25: comparison of oil recovery factor % with different conditions (concentration, salinity) at constant pore volume and 90 c conclusions the following conclusions are obtained from this study: 1. the permeability values which calculated by mathematical method (darcy equation) showed a clear differences comparing with graphical method due to many reasons such as differences in grain size , packing and reduction in flow rate in spite of high pressure according to the blockage of the sieve , so best fit line has been taken as experimental artifact of permeability. 2. secondary recovery by water flooding did not showing any significant effects when the injection ratio exceeded 1.2 pv because the recovery factor % increase slightly (60.2% at 1.2 pv – 66.7% at 8.0 pv). 3. the result of this study indicated that the best pv rate for water injection was 1.2 pv. productively, while the optimum injection rate was 1.0 pv economically. 4. it is clearly that the cost of water injection in secondary recovery increased 700% when pv injected increased from 1.0 pv to 8.0 pv, while the recovery increased only 8% (58.77 – 66.7%). 5. use of 0.01% molar of sds and 500 p.p.m salinity reduced density about 2% and use additional 5000 p.p.m of nacl reduced surface tension value about 15%. furthermore, increasing temperature from 30 – 70 c will resulting additional surface tension reduction about 12%, so as a result of all additions, surface tension reduced about 25%. so, the tests of surface tension led to identify the optimum conditions for tertiary recovery by using surfactant flooding . these conditions included 0.01 molar for concentration, 5500 p.p.m for salinity and 70 c for temperature. 6. all surfactant formulations were successful in terms of producing significant amounts of additional incremental oil (after water flooding), but the best oil recovery factor % obtained from sds flooding was better than the same operation at the same conditions by either criton x100 or ctab which were 89.94%, 85.6% and 85.9% respectively. http://www.iasj.net/ talib a. salih, safaa hussain sahi and ahmed noori ghani al-dujaili -available online at: www.iasj.net ijcpe vol.17 no.3 (september 2016) 27 7. again the 1.2 pv rate for surfactants injection was the best value economically because it was obviously that recovery factor % by sds, criton x100 and ctab increased 0.54%, 1.46% and 0.96% respectively when the pv rate changed from 1.2 pv to 2.0 pv. 8. according to the results and surfactant prices , the best surfactant productively and economically was sds then ctab while criton x100 was very expensive and inadequate unless additives have been used to improve the specifications of solution and reduce the cost to minimum value. references 1. s. q. tunio, a. h. tunio, n. a. ghirano, and z. m. el adawy, "comparison of different enhanced oil recovery techniques for better oil productivity," international journal of applied science and technology,vol. 1, 2011. 2. t. i. first, "waterflooding method," united states 3126952 a patent, 1964. 3. g. p. ahearn and w. w. gale, "surfactant-waterflooding process," ed: us patent 3,302,713, 1967. 4. l. holm, "miscibility and miscible displacement," journal of petroleum technology, vol. 38, pp. 817-818, 1986. 5. m. cissokho, s. boussour, p. cordier, h. bertin, and g. hamon, "low salinity oil recovery on clayey sandstone: experimental study," petrophysics, vol. 51, p. 305, 2010. 6. s. buelow sandersen, "enhanced oil recovery with surfactant flooding," ph.d. thesis, technical university of denmark 2012. 7. s. shaddel and tabatabae-nejad, "low salinity water flooding and combination of low salinity water flooding with surfactant and alkaline injection to improve oil recovery core flooding experiments," pp. paper 3-121, 2013. 8. g. hirasaki, c. a. miller, and m. puerto, "recent advances in surfactant eor," spe journal, vol. 16, pp. 889-907, 2011. 9. s. iglauer, y. wu, p. shuler, y. tang, and w. a. goddard iii, "new surfactant classes for enhanced oil recovery and their tertiary oil recovery potential," journal of petroleum science and engineering, vol. 71, pp. 23-29, 2010. 10. c. i. s. pwaga, o. hundseth, f. j. parales, m. u. idress, "comparative study of different eor methods," department of petroleum engineering, norwegian university of science & technology, trondheim, norway, 2010. 11. m. a. gholamzadeh and m. chahardahcherik, "optimization of injection rate and injection time for surfactant and water floodings in oil fields," international journal of advancements in research & technology, vol. 1, pp. 1-7, 2012. 12. l. xu, "optimizing surfactant additives for low-permeability wet gas formations: a laboratory approach for correlating capillary pressure and emulsion tendency with surfactant performance," presented at the spe eastern regional meeting, pittsburgh, pennsylvania, usa, 2013. 13. k. ma, "transport of surfactant and foam in porous media for enhanced oil recovery processes," ph.d degree, rice university, houston, usa 2013. 14. a. habibi, s. ayatollahi, s. ashoorian, and m. masihi, "effect of time and temperature on crude oil aging to do a right surfactant flooding with a new approach," in otc-24801-ms, offshore http://www.iasj.net/ using different surfactants to increase oil recovery of rumaila field (experimental work) 28 ijcpe vol.17 no.3 (september 2016) -available online at: www.iasj.net technology conference-asia, kuala lumpur, malaysia, 2014. 15. s. iglauer, m. sarmadivaleh, c. geng, and m. lebedev, "in-situ residual oil saturation and cluster size distribution in sandstones after surfactant and polymer flooding imaged with x-ray micro-computed tomography," in iptc 17312: international petroleum technology conference, doha, qatar, 2014. 16. t. nguyen, w. bae, and t. dang, "improvements of mixedsurfactants in alkaline/surfactant/polymer solutions," petroleum science and technology, vol. 32, pp. 1458-1464, 2014. 17. l. sun, k. spildo, k. djurhuus, and a. skauge, "salinity selection for a low salinity water-low salinity surfactant process," journal of dispersion science and technology, vol. 35, pp. 551-555, 2014. 18. h. h. hussain, "laboratory study of improving the transportation efficiency of oil in pipes," m.sc thesis, petroleum engineering department university of baghdad, baghdad, 2007. 19. a. chemika. (2014). sds http://www. alphachemikascientific.com/chemicals.htm. 20. c. book. (2014). sodium dodecyl sulfate,http://www.chemicalbook.co m/chemicalproductproperty_en_c b2147453.htm. 21. c. f. chemical, "http://www. cdhfinechemical.com/products/ laboratory-chemicals.asp .", 2014. 22. s. tripathi, "importance of surfactant adsorption in soil & ground water remediation," bachelor of technology, chemical engineering, national institute of technology rourkela, orissa, india, 2007. 23. t. dang-vu and j. hupka, "characterization of porous materials by capillary rise method," physicochemical problems of mineral processing, vol. 39, pp. 4765, 2005. 24. s. a. t. n. a. e. s. mohammad amin safarzadeh, "experimental investigation of the effect of calcium lignosulfonate on adsorption phenomenon in surfactant alternative gas injection," journal of chemical and petroleum engineering, university of tehran, vol. 45, pp. 141-151, 2011. 25. m. s. mehdi, s. eghbal, and a. t. n. seyyed, "experimental study of new improved oil recovery from heavy and semi-heavy oil reservoirs by implementing immiscible heated surfactant alternating gas injection," journal of petroleum and gas engineering, vol. 4, pp. 154-159, 2013. 26. a. samanta, k. ojha, a. sarkar, and a. mandal, "surfactant and surfactant-polymer flooding for enhanced oil recovery," advances in petroleum exploration and development, vol. 2, pp. 13-18, 2011. 27. c. i. s. pwaga, o. hundseth, f. j. parales, m. u. idress, "comparative study of different eor methods," department of petroleum engineering, norwegian university of science & technology, trondheim, norway, 2010. 28. a. ansari, m. haroun, n. al kindy, b. ali, r. a. shrestha, h. sarma, and a. dhabi, "electrokinetics assisted surfactant-eor to optimize mature waterfloods in abudhabi carbonate reservoirs," presented at the spe asia pacific oil & gas conference and exhibition, 2013 jakarta, indonesia, 2013. http://www.iasj.net/ talib a. salih, safaa hussain sahi and ahmed noori ghani al-dujaili -available online at: www.iasj.net ijcpe vol.17 no.3 (september 2016) 29 29. k. schaefer. (2012). waterfloods: the next big profit phase of the shale oil revolution, http://oilandgasinvestments.com/2012 /energyservices/waterfloods-the-next-bigprofit-phase-of-the-shalerevolution/. 30. k.-l. wang, l.-l. zhang, x. li, and y.-y. ming, "experimental study on the properties and displacement effects of polymer surfactant solution," journal of chemistry, vol. 2013, 2013. 31. s. kirk raney, s. s. ayirala, s. r. chin, and s. p. verbeek, "surface and subsurface requirements for successful implementation of offshore chemical enhanced oil recovery," 2011. 32. s. liu, "alkaline surfactant polymer enhanced oil recovery process," phd thesis, chemical engineering, rice university, houston, texas, 2008. 33. r. a. nasralla, m. b. alotaibi, and h. a. nasr-el-din, "efficiency of oil recovery by low salinity water flooding in sandstone reservoirs," in spe western north american region meeting, 2011. 34. j. a. thornton, "influence of apparatus geometry and deposition conditions on the structure and topography of thick sputtered coatings," journal of vacuum science & technology, vol. 11, pp. 666-670, 1974. 35. y. tang, b. du, j. yang, and y. zhang, "temperature effects on surface activity and application in oxidation of toluene derivatives of ctab-sds with kmno4," journal of chemical sciences, vol. 118, pp. 281-285, 2006. 36. v. m. ziegler and l. l. handy, "effect of temperature on surfactant adsorption in porous media," society of petroleum engineers journal, vol. 21, pp. 218-228, 1981. 37. s. a. t. n. mohammad amin safarzadeh, eghbal sahraei, and and m. m. salehi, "an experimental examination of adsorption phenomenon in foamassisted water alternative gas: the effect of injection rate," iranian journal of oil & gas science and technology, http://ijogst.put.ac.ir, vol. 3 (2014), pp. pp. 37-50, 2014. appendix a.1 sample no. weight (pipe + sand) gm weight (pipe + sand + water) gm water weight (gm)  % 1 1064.4 1101.7 37.3 35.18 2 1064.7 1101.5 36.8 34.71 3 1057.9 1093.8 35.9 33.859 4 1077.7 1114.3 36.6 34.519 5 1078.4 1114.7 36.3 34.236 6 1057.6 1094.8 37.2 35.085 7 1058.6 1096.6 38.0 35.84 8 1061.6 1098.0 36.4 34.33 http://www.iasj.net/ http://oilandgas-investments.com/2012%20/energy-services/waterfloods-the-next-big-profit-phase-of-the-shale-revolution/ http://oilandgas-investments.com/2012%20/energy-services/waterfloods-the-next-big-profit-phase-of-the-shale-revolution/ http://oilandgas-investments.com/2012%20/energy-services/waterfloods-the-next-big-profit-phase-of-the-shale-revolution/ http://oilandgas-investments.com/2012%20/energy-services/waterfloods-the-next-big-profit-phase-of-the-shale-revolution/ http://oilandgas-investments.com/2012%20/energy-services/waterfloods-the-next-big-profit-phase-of-the-shale-revolution/ using different surfactants to increase oil recovery of rumaila field (experimental work) 30 ijcpe vol.17 no.3 (september 2016) -available online at: www.iasj.net appendix a.2 sample no. p psi p atm. q cm 3 /sec p /l qµ/a 1 250 17.0115 4.445 1.1341 3.50563 2 450 30.62 5.987 2.04133 4.797916 3 500 34.023 6.752 2.2682 5.025845 4 650 44.23 9.241 2.94867 5.590733 5 700 47.6322 9.68 3.17548 7.281764 6 820 55.798 10.768 3.72 10.31752 7 1000 68.046 14.025 4.5364 3.108443 8 1500 102.069 19.872 6.8046 2.307839 appendix a.3 sample no. weight (pipe + sand) gm weight (pipe + sand + oil) gm oil weight (gm)  oil gm/cm 3 v oil cm 3 1 1064.4 1090.4 26.0 0.879 29.58 2 1064.7 1091.2 26.5 30.15 3 1057.9 1090.6 32.7 37.2 4 1077.7 1112.4 34.7 39.476 5 1078.4 1107.2 28.8 32.7645 6 1057.6 1087.9 30.3 34.471 7 1058.6 1089.6 31.0 35.2674 8 1061.6 1094.6 34.0 38.68 appendix a.4 sample no. pv injected % according to pvcore v oil cm 3 v oil secondary recovery cm 3 recovery % 1 50 29.58 11.8 39.892 2 75 30.15 15.2 50.415 3 90 37.2 20.8 55.714 4 100 39.476 23.2 58.77 14 120 35.722 21.5 60.2 5 200 32.7645 19.85 60.6 6 400 34.471 22 63.82 7 600 35.2674 23.1 65.5 8 800 38.68 25.8 66.7 appendix a.5 sample no. pv % injected to pvcore v oil cm 3 v oil secondary recovery cm 3 v oil after sec. recovery cm 3 v oil tertiary recovery (sds) cm 3 recovery % to sec. recovery recovery % to total v oil 5 50 32.7645 19.85 12.9145 4.8 37.17 75.23 6 75 34.471 22 12.471 6.2 49.71 81.8 7 100 35.2674 23.1 12.1674 7.45 61.23 88.3 8 200 38.68 25.8 12.88 8.95 69.49 89.94 4 120 39.1 26.3 12.8 8.65 67.58 89.4 appendix a.6 sample no. weight (pipe + sand) gm weight (pipe + sand + oil) gm oil weight (gm)  oil gm/cm 3 v oil cm 3 9 1063.7 1097.3 34.35 0.879 39.1 10 1062.6 1093.4 30.8 35.04 11 1061.7 1094.5 32.8 37.315 12 1059.8 1093.4 33.6 38.225 13 1060.3 1090.9 30.6 34.81 14 1065.2 1096.6 31.4 35.722 15 1066.1 1095.0 28.9 32.88 http://www.iasj.net/ talib a. salih, safaa hussain sahi and ahmed noori ghani al-dujaili -available online at: www.iasj.net ijcpe vol.17 no.3 (september 2016) 31 appendix a.7 sample no. pv injected % according to pvcore v oil cm 3 v oil secondary recovery cm 3 recovery % 9 100 39.1 23.2 59.33 10 200 35.04 21.4 61.07 11 50 37.315 15 40.2 12 75 38.225 19.3 50.5 13 100 34.81 20.3 58.32 14 120 35.722 21.5 60.2 15 200 32.88 20 60.83 appendix a.8 sample no. pv % injected to pvcore v oil cm 3 v oil secondary recovery cm 3 v oil after secondary recove0ry cm 3 v oil tertiary recovery cm 3 (criton) recovery % to sec. recovery recovery % to total v oil 1 50 29.58 11.8 17.78 3.8 21.37 52.74 2 75 30.15 15.2 14.95 7.15 43.48 74.13 3 100 37.2 20.8 16.4 9.75 59.45 82.12 9 120 39.1 23.2 15.9 9.7 61.00 84.14 10 200 35.04 21.4 13.64 8.6 63.05 85.6 appendix a.9 sample no. pv injected % according to pvcore v oil cm 3 v oil secondary recovery cm 3 v oil after secondary recovery cm 3 v oil tertiary recovery cm 3 (ctab) recovery % to sec. recovery recovery % to total v oil 11 50 37.315 15 22.315 7.25 32.49 59.63 12 75 38.225 19.3 18.95 9.37 45.38 75% 13 100 34.81 20.3 14.51 8.8 60.65 83.6 14 120 35.722 21.5 14.222 8.85 62.23 84.96 15 200 32.88 20 12.88 8.25 64.05 85.92 appendix a.10 sample no. pv % injected to pvcore conditions v oil after sec. recovery cm 3 sds injected volume cm 3 v oil tertiary recovery (sds) cm 3 recovery % to total v oil 1 50 0.1 molar (sds) 1000 p.p.m salinity 90 c 16.4 18.6 9.2 68.82 2 120 16.42 44.46 12.4 77.5 3 200 16.4 74.4 13.3 79.84 4 50 0.1 molar (sds) 3000 p.p.m salinity 90 c 16.48 18.6 9.8 70.65 5 120 16.46 44.46 13.1 79.5 6 200 16.45 74.4 13.9 81.6 7 50 0.001 molar (sds) 1000 p.p.m salinity 90 c 16.44 18.6 7.8 65.2 8 120 16.43 44.46 11.5 75.1 9 200 16.42 74.4 12.6 78.0 10 50 0.001 molar (sds) 3000 p.p.m salinity 90 c 16.4 18.6 8.82 67.8 11 120 16.4 44.46 12.1 76.6 12 200 16.42 74.4 13.0 79.2 http://www.iasj.net/ ijcpe vol.9 no.1 (march 2008) 23 iraqi journal of chemical and petroleum engineering vol.9 no.1 (march 2008) 23-29 issn: 1997-4884 pyrolysis of high-density polyethylene for the production of fuel-like liquid hydrocarbon ammar s. abbas* and sawsan d. a. shubar * chemical engineering department college of engineering university of baghdad – iraq abstract pyrolysis of high density polyethylene (hdpe) was carried out in a 750 cm 3 stainless steel autoclave reactor, with temperature ranging from 470 to 495° c and reaction times up to 90 minute. the influence of the operating conditions on the component yields was studied. it was found that the optimum cracking condition for hdpe that maximized the oil yield to 70 wt. % was 480°c and 20 minutes. the results show that for higher cracking temperature, and longer reaction times there was higher production of gas and coke. furthermore, higher temperature increases the aromatics and produce lighter oil with lower viscosity. keywords: pyrolysis, high density polyethylene, kinetics, activation energy. introduction polyethylene is the major component of the total plastic content of the municipal solid waste (msw). for example it represents 55 wt. % of total plastics consumed in australia in 2003 [1]. recycling is one of three ways for utilization and minimization of the huge amount of waste. the others are landfilling and incineration with or without energy recovery. neither landfilling nor incineration can solve the growing problem of huge amount of waste [2]. recycling can be classified into the following categories: primary recycling or re-extrusion, secondary mechanical recycling and tertiary (chemical or thermal recycling) [3]. pyrolysis involves the degradation of the polymers by heating in an inert atmosphere. the process is usually conducted at moderate temperatures between 400-800 °c and results in the formation of volatile fractions that may be separated into condensable hydrocarbon oil and a noncondensable high calorific value gas [4-6]. plastic pyrolysis may serve as a stand alone operation or preferably as a pretreatment to yield a stream to be blended into a refinery or petrochemical feed stream [7], where the liquid obtained had a low octane number although the oil has a high cetane number due to its low aromatics content [8]. polyolefin resins (contain only carbon and hydrogen i.e. pe, pp) of various origins are a desirable pyrolysis feedstock [9]. so, pyrolysis appears to be a technique that is able to reduce a bulky, high polluting industrial waste while producing energy and/or valuable chemical compounds [10]. as an advantage, pyrolysis can treat all the mixtures consisting of various types of plastics without separation or treatment [11]. the produced oil is distributed to end users, typically as a cheaper substitute for heavy oil and it can be used in industrial boilers, burners, and power generators [12]. university of baghdad college of engineering iraqi journal of chemical and petroleum engineering pyrolysis of high-density polyethylene for the production of fuel-like liquid hydrocarbon ijcpe vol.9 no.1 (march 2008) 24 ng et al. [8] held a thermal decomposition for pe in a batch reactor at a temperature range of 450 to 500° c, and the reaction was carried out for 10 minute. the final pressure at the reaction temperature ranged from 1.38 to 16.13 mpa. the gases were analyzed by gas chromatography, and the other products were separated into naphtha, gas oil and residue by distillation. the amount of residue decreased with temperature, and the amount of gas increased with temperature. the yield of gas oil was maximized at 470° c, and it consisted primarily of normal saturates and lesser amounts of αolefins. only small amounts of branched hydrocarbons were detected in pyrolysis products. pinto et al. [13] carried out thermal decomposition for pe and pp in 1 liter autoclave .they tried to optimize the polymer pyrolysis on experimental conditions used. it was suggested that the run temperature of 450° c, reaction time of 30 min and an initial pressure of 0.14 mpa is the optimum. the alkanes formed in greater amounts were those with carbon atoms between 5 and 11. branches and cycled alkanes appeared in very low concentrations with the exception of methylcyclohexane. miskolczi et al. [2] applied thermal cracking for polyolefin's (pe, pp) at 525° c with a horizontal tubular reactor. it was found that the cracking parameters (the type of waste polymers and residence time) affected not only the yields but also the composition of products. miller et al., [14] used a thermal atmospheric pressure pyrolysis that converts high molecular weight molecules to lower molecular weight in the lube oil range. the major by product is diesel with little production of c4gas. the pyrolysis yield products were in the range of 37 to 57 wt. %, whereas the potential lube yields were 60-70 wt. %. the aim of this work is to investigate the pyrolysis behavior of hdpe in a batch process. the effects of the cracking parameters (reaction temperature and residence time) on the yield, group composition, distribution of distillate fractions and final properties of fuel like liquid products were also investigated. experimental work materials feedstock hdpe pellets were obtained from the state enterprise of petrochemicals industry/basrah. the main properties of hdpe polymer are shown in table 1. nitrogen gas nitrogen gas was supplied from dijlah factory with a purity of 99.9%. table 1 physical and chemical properties of feedstock property hdpe sepilex hhm5502 test method density (g/cm3) 0.9550 astmd 1505 melt flow index (g/10 min) 0.35 astmd 1238 deflection temperature (°c) 75-80 melting point (°c) 130-135 average particle diameter (mm) 3 pyrolysis apparatus and procedure the pyrolysis was performed in a 750 cm 3 stainless steel autoclave of 5 mm thick wall, equipped with a motor driven stirrer with two blades used for agitation. thermocouple (type k) with digital temperature recorder was used. a pressure gauge 1250 bar (0.1-25mpa) was connected to the top of the reactor to read the pressure inside the reactor. heat was supplied to the reactor by 1200 watt electrical heater connected to a voltage regulator in order to adjust the heating temperature. a schematic diagram of the experiments is shown in fig. (1). a tubing system was connected to the top of the reactor. all tubing had (302 mm od and 204 mm id) thick stainless steel wall. a big metal container positioned in a cooler was ready to quench the reactor inside it after each run. the quenching process was done by using cooled water at 4° c. the autoclave was first cleaned with sand paper, and solvents, and then it was loaded with a measured amount (175 g) of the pellets and closed. the autoclave was then bolted tightly and evacuated by applying vacuum 0.068mpa then tested with n2 gas by flushing the system twice to remove any air present. the reactor was closed at atmospheric pressure and it generated maximum pressure of approximately 5mpa at 495° c. after the charged feed reached 200° c, the stirrer was put in motion. reactor temperature was increased to the pre-set temperature by turning on the electrical heater. the accuracy of temperature readings was less than 5° c and the time zero was taken as the time after which the reaction melt reached the specified reaction temperature. after reaching the specified time in any temperature the heating was stopped and the reactor quenched in the water bath of 4° c. then, after reaching about 25° c, the gaseous products were vented and the products were weighted. the mass balance of reactants and products was estimated and analyzed. ammar s. abbas and sawsan d. a. shubar ijcpe vol.9 no.1 (march 2008) 25 mixer gauge pressure flange electrical heater reactor impeller needle valve electrical power regulator to vacuum or n2 inlet fig. 1 schematic diagram of the experimental apparatus analysis methods yields calculations the mass of gas formed was determined by the weight loss after discharging. the product slurry was then removed from the reactor. about 10 g of the slurry product was solvent-extracted with hexane to remove the oil formed. the hexane-insoluble were extracted with thf to remove asphaltenes and preasphaltenes. in all these runs, the amounts of asphaltenes and preasphaltenes were negligible. the thf-insolubles were then extracted with decalin at 140 °c [15]. preliminary distillation (ip 24/55) 50 cm 3 liquid product was distillated in atmospheric pressure and constant heating rate (about 5 cm 3 /min) in the following fractions: (ibp-140° c), (140-200° c), (200-270° c) and (>270° c). other tests  method of measuring aromatic plus olefin fractions (astm d 1019-68).  olefin content (ip 128/63).  liquid density measurements (astm d 1505). the density was taken to both the fuel like product and the light distillate (<270°c).  liquid viscosity (astm d 2515). results and discussion effect of reaction time and temperature on product yield the effect of reaction time on the formation of gas, oil, coke and un-reacted polymer at different reaction temperature was studied in time range up to 90 minute. results of this investigation were presented in fig. 2 to fig. 4. for hdpe pyrolysis at 480° c the gas increased to about 56 wt. % , while at 495° c it increased up to 69.5 wt. %. it can be deduced that the primary pyrolysis of pe takes place through a free-radical transfer that leads to low yield of gases. nevertheless, the more gases obtained from secondary pyrolysis of waxes at gas phase can be interpreted as a consequence of the propagation reaction [16]. the produce oil at 470° c increased up to a maximum yield about 71 wt. % at about 30 minute and then decreased to reach about 50 wt. % at 90 minute as in fig.2. the oil produce from hdpe at 480° c reaches maximum (about 70) at 20 minute and then decreases with the reaction time increases, as seen in fig. 3. hence, there exists an optimum reaction time at which the liquid products are maximized. this optimum time occurs around at 20 minutes for hdpe. ramdoss and tarrer, [17] found that optimum time was 5-10 minutes for producing oil from post consumer pe and pp waste at 500°c. the other observation in fig.s 2 to 4 was the coke formation where the coke raised up to 0.5 wt % at 480° c and 90 minute for hdpe pyrolysis as in fig. 3. coke formation was likely the result of the secondary reactions of products (coke precursors) formed during the primary pyrolysis process. these results agree with those of horvat and ng, [18]. the experimental results in fig.s 2 to 4 show that practically all the mass of pe is exhausted when the maximum point for oil production was reached. the oil yield decreased since the secondary gas and coke were formed. it is also seen that the mass fraction of the plastic being decomposed decreases with pyrolysis time. park et al. [19] and walendziewski [20] had concluded that shorter times favor larger yields of liquid and longer reaction times favors larger gas yields at the same temperature. the main effect of increasing temperature within this range of temperature 470 to 495° c was increases the rate of formation of gases and decreases the rate of formation of solid residue (un-reacted plastic). fig. 5 demonstrates the effect of temperature on the yield of gas, oil, coke and plastic itself (hdpe) at the optimum time. it was found that the gas yield resulting from decomposition hdpe increased from about 14 wt. % to about 25 wt. % when the pyrolysis temperature was raised from 470° c to 495° c. this increasing in gas yield was probably due to the increase in the rate of main chain sigma bond cleavage reactions in the more thermally energetic high temperature environments. also the growing yield of gas could be caused by the differences in stability of polymer chains. therefore at 495° c, the c-c bonds cracked more rapidly than at lower temperature (i.e. 470° c) and these results in higher gas yield [18]. pyrolysis of high-density polyethylene for the production of fuel-like liquid hydrocarbon ijcpe vol.9 no.1 (march 2008) 26 time, min 0 20 40 60 80 100 y ie ld , % 0 20 40 60 80 100 hdpe o c g temp.= 470 o c fig. 2 yields of different products from pyrolysis of hdpe at 470° c reaction temperature time, min 0 20 40 60 80 100 y ie ld , % 0 20 40 60 80 100 hdpe o c g temp.= 480 o c fig. 3 yield of different products from pyrolysis of hdpe at 480° c reaction temperature time, min 0 20 40 60 80 100 y ie ld , % 0 20 40 60 80 100 hdpe o c g temp.= 495 o c fig. 4 yield of different products from pyrolysis of hdpe at 495° c reaction temperature the effect of temperature on the yield of oil was tracked. there was an increase in the yield of oil from about 67 wt. % to about 69 wt. %. then, it could be seen that there was a slight decrease in oil yield at optimum cracking time. it was noticed that the decomposition temperature influence the amount of volatile products. as the decomposition temperature increases the minimum length of the fragment which can evaporate under the prevailing conditions also increases [10, 21]. the effect of temperature on coke formation at fixed time was also studied. it can be seen from fig. 5 that the coke increased from about 0.05 wt. % at 470° c to about 0.23 wt. % at 495° c, both at 20 minute for hdpe pyrolysis. the reason might be the mobility of the thermally generated free radicals. temperature, o c 465 470 475 480 485 490 495 500 y ie ld , % 0 20 40 60 80 hdpe o c g time= 20 min fig. 5 variation of components yield with pyrolysis temperature of fuel like liquid produced from hdpe pyrolysis at 20 minute reaction time the effect of reaction temperature on the plastic itself was shown in fig. 5. it is clear that the decomposition of hdpe increased with increasing reaction time. these observations are in good agreement with the results of conesa et al. [16] and wong et al. [22]. the density and viscosity of produced fuel-like liquid hydrocarbon were 0.9076 g/cm 3 and 2.056 cst, respectively, at 480° c and 20 minute. effect of reaction time and temperature on group composition from fig. 6 it is obvious that aromatic is formed in a large extent with increasing the pyrolysis time. it can be raised up from about 11 to about 15 wt. % for hdpe at 480° c and 90 minutes reaction time. this indicates that higher aromatic content was found with higher residence times. the cause may be that in closed systems volatile products remain in the reaction zone and are in equilibrium with liquid phase and can contribute to secondary reactions, such as ring formation and aromatization. mosio-mosiewski et al. [23], pinto et al. [13] and ng, et al. [8] agreed with this trend. ammar s. abbas and sawsan d. a. shubar ijcpe vol.9 no.1 (march 2008) 27 the effect of pyrolysis time on the alkene content during hdpe pyrolysis is obvious in fig. 6. it can be seen that the alkene content decreased slightly from about 15 % at 10 minute to 11% at 90 minutes and 480° c for hdpe. the reason of this phenomenon was the probabilities of secondary reactions (e.g. repolymerization of alkenes) become higher with long cracking time [2]. the effect of reaction temperature in the ranges of 470 to 495° c on the relative amounts of alkanes, alkenes and aromatics at their optimum reaction time, where shown in fig. 7, which illustrated that the aromatic content at the optimum time for the polymers increases with increasing the temperature. group types alkane alkene aromatic g ro u p c o m p o s it io n , w t % 0 20 40 60 80 100 time = 10 min time = 20 min time = 30 min time = 45 min time = 60 min time = 90 min hdpe, reaction temperature = 480 o c fig. 6 group composition analysis of fuel like liquid (<270° c) produced from pyrolysis of hdpe at 480° c reaction temperature the aromatic content increased from about 4 to about 15 wt. %. the formation of aromatics at high temperatures occurs due to lighter hydrocarbons such as ethene and propene reacting to form aromatic compounds as benzene and toluene. it was reported that at higher temperatures ethene and propene were unstable [24]. fig. 7 shows that the increase in this temperature range started to decrease alkenes from about 17 to about 11 wt. %. according to the mechanism of alkane and alkene formation, alkene formation is a uni-molecular reaction and alkane formation is a bimolecular reaction. so, higher temperature makes alkane formation (intermolecular propagation reaction), the more favorable reaction. bockhourn et al, [25] pointed out that the contribution of energies of activation energy to the apparent alkane and alkene formation was 42 and 112 kj /mol, respectively. group types alkane alkene aromatic g ro u p c o m p o s it io n , w t % 0 20 40 60 80 100 temp. = 470 o c temp. = 480 o c temp. = 495 o c ldpe, reaction time = 10 min fig. 7 group composition analysis of fuel like liquid (<270° c) produced from pyrolysis of hdpe at 20 min reaction time effect of reaction time and temperature on the distillate fractions the effect of pyrolysis time on the relative amount of fractions of oil produced from atmospheric distillation was shown in fig. 8. it can be seen that the first two fractions ibp-140° c and 140-200° c increased with increasing pyrolysis time up to 90 minute. the first fraction ibp-140° c raised from 6 wt % to 15 wt % and the second fraction (140-200 °c) raised from 15 wt % to 36 wt %. the third fraction (200-270° c) increased slightly during the first 45 minute, and then it began to decrease. while the residue (>270°c) decreased sharply during the first 45 minute, then it began to increase slightly. the results suggest that as pyrolysis time increased, the heavier products decomposes to lighter ones, because at higher pyrolysis time the carbon chain was exposed to more forceful thermal decomposition effects, due to its being under harsh environment for a long time. rangarajan et al. [25] and walendziewski and steininger [9] agreed with these findings. when distilling the fuel like products from hdpe pyrolysis, it was noticed that the first two fractions (ibp140° c and 140-200° c) increased with increasing the pyrolysis temperature from 470 to 495° c at fixed reaction time. the heavier fractions (200-270° c) and the residue (>270° c) decreased with increasing the reaction temperature for both polymers, as shown in fig. 9. pyrolysis of high-density polyethylene for the production of fuel-like liquid hydrocarbon ijcpe vol.9 no.1 (march 2008) 28 distillation fraction range, o c ibp-140 140-200 200-270 > 270 d is ti ll a te , w t. % 0 10 20 30 40 50 60 70 time = 10 min time = 20 min time = 45 min time = 60 min time = 90 min hdpe, reaction temperature = 480 o c fig. 8 variation of distillate fractions weight percent with reaction time of fuel like liquid produced from hdpe pyrolysis at 480° c reaction temperature distillation fraction range, o c ibp-140 140-200 200-270 > 270 d is ti ll a te , w t. % 0 10 20 30 40 50 60 temp. = 470 o c temp. = 480 o c temp. = 495 o c hdpe, reaction time = 20 min fig. 9 reaction temperature effects on the distribution of distillate fractions of fuel like liquids and light products out from hdpe pyrolysis at 20 minute this may be explained that among the various product fractions in each of the polymers, higher energy would be required to produce lighter fractions because on the average it takes more derivative steps to form the lighter products. also high temperature increased the rate of volatilization of longer chains, where they undergo βscission at a rate much higher than that found in light fractions. this observation fit the trend observed by ranjargan et al. [25]. conclusions based on present work, the following points can be concluded: 1. pe pyrolysis yields a mixture of oil, gas. the higher the pyrolysis temperature and the longer the reaction times increase the gas yield. 2. there was an optimum temperature and pyrolysis time and which the liquid products is maximized. this optimum temperature occurs around 480 °c and the optimum reaction time was 20 minute for hdpe with oil yield 69.2 wt %. 3. it was found that for higher cracking temperature and longer reaction time, there was higher production of gases and coke. gas yield was increase from 14.23 % at 470° c to 25.78 % at 495° c at 20 minute reaction time, while gas yield increased up to 55.92 % at 90 minute. 4. aromatics increased with temperature and time while alkenes decreased. 5. distillation of fuel-like liquids show more light fractions for fuel like liquid produced at higher temperature and longer time. nomenclature c mass fraction of coke , wt. % e activation energy , j/mol g mass fraction of gas , wt. % o mass fraction of oil, wt. % p mass fraction of un-reacted plastics , wt. % references 1. hackett, c., williams r. b., [2004], "evaluation of conversion technology processes and products", journal of anal. and applied pyrolysis, 52, 87-103. 2. miskolczi, n., bartha, l., deak, gy. , [2003], ''chemical recycling of waste pe and pp '', petroleum and coal 45,125-130. 3. miskolczi, n., bartha, l., deak, g.y., jover, b., kallo, d. [2004], ''kinetic model of the chemical recycling of waste polyethylene into fuels",' trans icheme, part b, 82,223-229. 4. aguado, j., serrano, d., vicenle, g., sanchez, n., [2006], "effect of decalin solvent on the thermal degradation of hdpe", journal of polymers and the environment, 14,375-384. 5. kaminsky, w. menzel j., sinn, h., [1976], "recycling of plastics", conversation and recycling, 1, 19. 6. shah, n., rockwell, j., huffman g.p., [1999], '' conversion of waste plastic to oil: direct liquefaction versus pyrolysis and hydro processing '', energy and fuels, 13, 832-838. 7. beltrame, p. l., carniti, p., [1989], '' catalytic degradation of polymer: part 2-degradation of polyethylene'', poly. degrad. and stab.26, 209-220. 8. ng, s.h., seoud, h., stanciulescu, m., [1995], '' conversion of pe to transportation fuels through pyrolysis and cracking '', energy and fuels, 9, 735742. ammar s. abbas and sawsan d. a. shubar ijcpe vol.9 no.1 (march 2008) 29 9. walendziewski, j., steininger, m., [2001], "thermal and catalytic conversion of waste polyolefin "catalysis today, 65, 323-330. 10. demirbas, a., [2004],"pyrolysis of municipal plastic wastes for recovery of gasoline-range hc" journal of anal. appl. pyrolysis 72, 97-102, 11. lee, k-h, shin, d-h, [2006], ''characteristics of liquid product from the pyrolysis of waste plastic mixture at low and high temperatures'', waste management, feb, 28. 12. koreda, y., ishihara, y., [2006], "novel process for recycling waste plastics to fuel gas using a moving bed reactor", energy and fuel, 20,155-158. 13. pinto, f., costa, p., gulyurtto, i. and cabirta i. [1999], "effect of experimental parameters on plastics pyrolysis reactions'' paper presented at the r99 congress, feb.1. 14. miller, s.j., shah, n. huffman, g.p., [2000], ''conversion of waste plastic to lubricating base oil'' energy and fuels, 19, 1580-1586. 15. robbins, g.a., winschel, r. a., burke, f .p. [1996], "determination of unconverted hdpe in coal/plastics co-liquefaction stream samples" acs preprint, american chemical society. 16. conesa, j.a.; font, r. and marcilla, a., [1997],"comparison between the pyrolysis of two types of polyethylene in a fluidized bed reactor" energy and fuels, 11,126-136. 17. ramdoss p.k., tarrer a.r., [1998], "hightemperature liquefaction of waste plastics" fuel, 77,293-299. 18. horvat, n., ng, f.t.t., [1999], '' tertiary polymer recycling: study of pe thermolsis as a 1st step to synthetic diesel fuel '', fuel, 78, 459470. 19. park, j.j., park, k., park, j-w., kim, d.c., [2002], '' characteristics of ldpe pyrolysis '', korean journal chem. eng. 19, 658-662. 20. walendziewski, j., [2002], "engine fuel derived from waste plastics by thermal treatment" fuel, 55, 473-481. 21. mastral, j.f, berrueco, c., ceamanos, j., [2006],''pyrolysis of hdpe in free-fall reactors in series '' energy and fuels 20, 1365-1371. 22. wong, h-w. , broadbelt, l.j., [2001], '' tertiary resource recovery from waste polymers via pyrolysis: neat and binary mixture reactions of polypropylene and polystyrene '' ind. eng. chem. res., 40, 4716 -4723. 23. mosio-mosiewski j., warzala, m., morawski, i., tadeusz, d., "high-pressure catalytic and thermal cracking of polyethylene" fuel processing technology, 88,359-364, (2007). 24. westerhout, r.w.j., kuipers, j.a.m, swaaij, w.p.m.," experimental determination of the yield of pyrolysis products of pe and pp: influence of reaction conditions" ind. eng. chem. res.37, 841-847, (1998). 25. rangarajan, p., bhattacharyya, d., grulke, e., ''hdpe liquefaction: random chain scission model ''j. of applied polymer science, 70, 1239-1251(1998). ijcpe vol.11 no.1 (march 2010) iraqi journal of chemical and petroleum engineering vol.11 no.1 (march 2010) 47-53 issn: 1997-4884 pc-based controller for shell and tube heat exchanger naseer a. habobi * chemical engineering department college of engineering university of nahrin – iraq abstract pc-based controller is an approach to control systems with real-time parameters by controlling selected manipulating variable to accomplish the objectives. shell and tube heat exchanger have been identified as process models that are inherently nonlinear and hard to control due to unavailability of the exact models’ descriptions. pc and analogue input output card will be used as the controller that controls the heat exchanger hot stream to the desired temperature. the control methodology by using four speed pump as manipulating variable to control the temperature of the hot stream to cool to the desired temperature. in this work, the dynamics of cross flow shell and tube heat exchanger is modeled from step changes in cold water flow rate (manipulated variable). the model is identified to be first order plus dead time (fopdt). the objective of this work is to design and implement a controller to regulate the outlet temperature of hot water that is taken as controlled variable. the comparison of the designed pi controller with the pc-based controller performance (according to rise time, percentage overshoot and settling time) shows a good agreement for pc-based to control the system. keywords: pc-based controller, shell and tube heat exchanger, real time controller. introduction pc-based controller is becoming more widespread in process plants and it is characterized by, lower costs which occur in two ways. one, it‟s much cheaper to combine operator interface and control into one pc-based system than using a pc and a plc (programmable logic controller). not only purchased costs are lower, but integration between the pc and the (plc) is eliminated. the second main cost saving occurs because pcs can outperform similarly priced plcs [1]. pc-based controller is often achieved via the rs232 interface using simple text strings. once automation professionals become comfortable with pc-based controller through purchased systems, it‟s a short step to implementing pc-based controller for control of their own critical processes. for industrial systems, the controller is typically sampling thermocouples directly, and in some cases using a separate data acquisition board, communicating with the controller via a serial port [1]. shell and tube heat exchangers (sthe) are among the more confusing pieces of equipment for the process control engineer. and their control is difficult yet important problem due to its nonlinearity [2]. the temperature of the two fluids will tend to equalize. by arranging counter-current flow, it is possible for the temperature at the outlet of each fluid to approach the temperature at the inlet of the other. the heat contents are simply exchanged from one fluid to the other and vice versa [3]. in sthe the heat demands of the process are not constant, and the heat content of the two fluids is not constant either. the heat exchanger must be designed for the worst case and must be controlled to make it operate at the particular rate required by the process at every moment in time. the characteristics of the heat exchanger are not constant and vary with time. the most common change is a reduction in the heat transfer rate due to fouling of the surfaces [3]. there is only one variable that can be controlled in this case the amount of heat being university of baghdad college of engineering iraqi journal of chemical and petroleum engineering pc-based controller for shell and tube heat exchanger 48 ijcpe vol.11 no.1 (march 2010) exchanged. in practical situations it is not possible to measure heat flux. it is always the temperature of one fluid or the other which is being measured and controlled. it is not possible to control both since the heat added from one is taken from the other. to consider which of the streams to manipulated, the complications arise from the fact that exchangers have four ports and involve two different fluids, either of which may change phase. figure 1 assumes that it is the fluid on the tube side whose temperature is being controlled. as likely as not, it is the one on the shell side issue whose fluid is to be manipulated by changing the flow rate. figure 1. shell and tube heat exchanger control loop. experimental work the heat exchanger used in this work is cross flow sthe containing four tubes (14×16 mm), with nine baffles, shell (355×50 mm dia). the exchanger of 355mm length and 0.06738 m 2 surface area. the hot water is in the tube side while the cold water is in the shell side. in figure 1 cold water in 17.2°c is pumped through control valve then flowmeter before entering the shell side of the heat exchanger. while the hot side (tube side) heated water flows from reservoir at constant temperature of 60°c. four digital temperature sensors (ds1820) are used to collect the required data. a computer interface is built to demonstrate the feasibility of the concepts with four relays to give the output control signal as in figure 2. figure 2. interface card with 4 input digital temperature sensors and 4 output relays. commands for reading temperatures or controlling relays are sent via the rs232 interface using simple text strings to the computer. this kit can be controlled by sending an electrical signal via simple terminal, communications program (such as hyperterminal) or via visual basic. in this work, the third option is used where a visual basic6 program is used to achieve the required tasks. the program is taken from www.ozitronics.com and modified specifically for the research problem according to the manipulated variable (pump speed) with four relays and the controlled temperature (output temperature of the hot side) as shown in figure 3 and figure 4. figure 3. window of visual basic executable program. naseer a. habobi 49 ijcpe vol.11 no.1 (march 2010) figure 4. schematic software specified to control the process. pc-based controller for shell and tube heat exchanger 50 ijcpe vol.11 no.1 (march 2010) it is necessary to identify model parameters from experimental data. the simplest approach involves introducing a step test into the process and recording the response of the process. then step changes in cold flow rate of water (18.5 °c) are applied 50-100, 100-150, and 150-200 lit/hr. the response for the outlet temperature of hot water (entered at 60°c) is shown in figure 5. it has been recognized that a first order plus dead time (fopdt) may in general represent process dynamics of the heat exchanger [4]. the calculations are carried further to estimate the pseudo dead time and the process time constant. figure 6 shows the open-loop test for the three step changes in manipulating variable flowrate of cold water from 50 to 200 lit/hr. by using the „two-point method‟, which does not require the drawing of a tangent line but measures the times at which the process changes by 28.3% (t1) and 63.2% (t2) of the total process change[5]. process time constant τ = 1.5 (t2-t1) pseudo dead time td = t2-τ figure 5. outlet temperature response of hot water to step change for open loop test for manipulating flow rate 50100 lit/hr. figure 6. open loop temperature responses with three different step changes 50-100, 100-150 and 150-200 lit/hr. the values of the t1 and t2 are 12 s, and 20 s respectively. the process parameters are: = -0.19 °c/% and τ = 36 s, td = 19 s this process has a negative steady-state process gain, and the transfer function of the first order plus dead time (fopdt) can be deduced as follow: initial estimation for controller parameters the design of a controller requires specification of the parameters: proportional gain (kp), integral time constant (ki), and derivative time constant (kd). there is crucial problem to tune properly the gains of pid controllers because many industrial plants are often burdened with the characteristics such as high order, time delays and nonlinearities [6]. ziegler-nichols closed loop tuning method is used to find the optimal pid parameters. the optimal parameters obtained for the cold water flowrates are applicable over the entire useful range (50 to 200 naseer a. habobi 51 ijcpe vol.11 no.1 (march 2010) lit/hr) which is represents 25% to 100% from the controller output. the performance of the controller depends as much as on tuning the parameters as its design. tuning must be applied by the end user to fit the controller to the controlled process. there are many different approaches to controller tuning based on the particular performance criteria selected, whether load or set point changes are most important, whether the process is lag or dead time dominant, and the availability of information about the process dynamics [7]. traditionally, the problem is handled by a trial and error approach. design engineers must tune pid controllers manually and usually take considerable time [8]. according to ziegler-nichols method [9], the estimation of pid parameters are: k= time constant/ (process gain × dead time) pid: proportional gain=1.2 × k, integral time =2 × dead time, derivative time = 0.5 × dead time from the formula, the parameters are kp=-12 ki=38 kd=9.5 to verify the pid parameters, matlab-simulink is used to simulate the system depicted in figure 7. the investigation reveals that the optimum solution is a pi controller with the following kp= -7 ki=0.24 kd=0. so the process model compares of pi with the experimental data of pc-based controller are plotted on the same figure (figures 8-11). figure 7. matlab simulink close loop control process. the optimal parameters are very sensitive to the physical characteristic of the heat exchanger including tubes length and diameter (kp). experimental results the constructed pc-based controller is implemented with the heat exchanger system to control the feed rate of cooled side. this is achieved by changing the pump speed to give 50, 100, 150 and 200 lit/hr as manipulating variable to control the temperature of output for the hot side of heat exchanger figure 8-10 show, respectively, the experimental data that correspond to folwrate changes 50-100, 100-150 and 150-200 lit/hr, figure 11 give the complete controlled range. where the figure 11 shows the experimental for the sthe run under pc-based controller (continuous line) to study the performance of the controller are subjected to multiple disturbance and compare it along with the conventional controller (dotted line). set point changed at time zero from steady state condition of temperature 55 °c of outlet hot stream (50 lit/hr and relay 1 on) into 49 °c (100 lit/hr and relay 2 on) for 500 sec long time then the set point changed into 44 °c (150 lit/hr and relay 3 on) at time 500 sec for another 500 sec period then the set changed at time 1000 sec into 41 °c (200 lit/hr and relay 4 on) for the rest time. figure 8. response for the close loop control process for 50 to 100 lit/hr flow rates of cold side for experimental (pc-based controller) with pi controller. figure 9. response for the close loop control process for 100 to 150 lit/hr flowrates of cold side for experimental (pc-based controller) with pi controller. 50 lit/hr 100 lit/hr 150 lit/hr 200 lit/hr pc-based controller for shell and tube heat exchanger 52 ijcpe vol.11 no.1 (march 2010) figure 10. response of the close loop control process for 150 to 200 lit/hr flowrates of cold side for experimental (pc-based controller) with pi controller. figure 11. response for the close loop control process for 50 to 200 lit/hr flowrates of cold side for experimental (pc-based controller) with pi controller. the data obtained from the calculation for i/o interface and pi is summarized in table 1 to compare the performance of each controller. it is noted that pi has a faster rise time compared to pc-based controller and need less time to achieve the set point value. pc controller give zero percent overshoot, pi can be retuned by changing the kp value while pc-based controller can be retuned by changing software architecture. table 1. the performance of pi and pc-based controller pi controller pc-based controller rise time tr 360 s 65 s stilling time ts 10 s 100 s max. overshoot %mp 55 0 the performance of the pc-based controller is studied for different set points in range of 55-41 °c reexamined in terms of rise time 65s, percentage overshoot 0% , and settling time 100. conclusions heat exchanger is highly nonlinear process; therefore modeled using two point method to identify the process which is first order plus dead time (foptd) and by using ziegler-nichols method to estimate the controller parameter and tuned by matlab simulink to give pi controller, pi controller has sensitive proportional gain. pc-based control was applied to a heat exchanger and compared with proposed pi controller; actually the comparisons are made between the process performance (rise time, percentage overshoot, and settling time). the results show that the pc-based controller is a fast representation for the corresponding processes and pcbased that control the temperature of hot side to the desired set point by manipulating the cold side flowrate using multispeed pump (50, 100, 150 and 200 lit/hr) give an encouraging performance to control the heat exchanger with low cost. references 1 dan hebert, pe “pc-based control infiltrates process plant” process automation technologies/soft ware and integration 05/15/2006. 2 erkan imal “cdm based controller design for nonlinear heat exchanger process” turk j elec & comp sci, vol.17, no.2, 2009. 3 walter driedger, p “controlling shell tube exchangers” hydrocarbon processing, march 1998. 4 d. r. coughanowar, process system analysis and control, tata mcgraw hill, 1991. 5 w. b. bequette, process control modeling and simulation, prentice hall, 2003. http://www.controlglobal.com/contact_us/dhebert.html naseer a. habobi 53 ijcpe vol.11 no.1 (march 2010) 6 g. j. silva and a. datta, et al., new results on the synthesis of pid controllers, ieee transactions on automatic control, 47, 2, 2002, pp. 241-252. 7 richard c. d. and robert h. b, “modern control systems”, 9th edition, prentice-hall, inc., new jersey, 2001. 8 gopalakrishna g., sivakumaran n. and sivashanmugam p. “enhancement of heat exchanger control using improved pid” controllersensors & transducers journal, vol. 107, issue 8, august 2009, pp. 144-156. 9 ziegler, j.g. and nichols, n.b. “optimum settings for automatic controllers”, transactions of the asme, november (1942), pp. 759–768 available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.20 no.1 (march 2019) 1 – 7 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: neaam f. hussain , email: neaam_1994@yahoo.com, faleh h. m. al mahdawi, email: fhmetr@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. prediction of fracture pressure gradient in halfaya oilfield neaam f. hussain and faleh h. m. al mahdawi university of baghdad/ department of petroleum engineering abstract fracture pressure gradient prediction is complementary in well design and it is must be considered in selecting the safe mud weight, cement design, and determine the optimal casing seat to minimize the common drilling problems. the exact fracture pressure gradient value obtained from tests on the well while drilling such as leak-off test, formation integrity test, cement squeeze ... etc.; however, to minimize the total cost of drilling, there are several methods could be used to calculate fracture pressure gradient classified into two groups: the first one depend on poisson’s ratio of the rocks and the second is fully empirical methods. in this research, the methods selected are huubert and willis, cesaroni i, cesaroni ii, cesaroni iii, eaton, and daines where poisson’s ratio is considered essential here and the empirical methods selected are matthews and kelly and christman. the results of these methods give an approximately match with the previous field study which has been relied upon in drilling the previous wells in the field and cesaroni i is selected to be the equation that represents the field under study in general. in the shallower formations, cesaroni i is the best method; while in deepest formations, eaton, christman, and cesaroni i are given a good and approximately matching. the fracture pressure gradient of halfaya oilfield range is (0.98 to 1.03) psi/ft. keywords: fracture pressure, fracture pressure gradient, halfaya oilfield. received on 10/10/8102, accepted on 02/12/8102, published on 30/03/8109 https://doi.org/10.31699/ijcpe.2019.1.1 1introduction fracture pressure is the required injection pressure to rupture the formation. while penetrating an abnormal formation pressure, the mud density should be increased to maintain the well bore stability and continue safe drilling. however, the mud pressure should remain below the pressure that causes formation damage; that’s why the estimation of fracture gradient is complementary in well design. the underground stresses which resist formation fracture can be defined as as shown in fig. 1 fig. 1. underground stresses [1]. the origin of these stresses is that; during sedimentation, grains will ensure one on the other; over time, and with continuing sedimentation the layers above a specific points causes an overburden pressure ( which is a combination of matrix weight and pressure of fluid within pores. thus, the effective vertical stress ( is equal to overburden pressure above a specific point subtracted the pore pressure at this point from it. the increment of grain to grain loading due to the vertical stress will expand the grains laterally but, that prevented by the nearby grains so that horizontal stresses and will develop ‎[1]. the fracture direction is perpendicular to the least stress axis. in tectonically relaxed areas, the least stress is the horizontal stress ( or ), therefore; the fracture direction will be vertical and the pressure causes this fracture is less than the overburden pressure; while in active tectonic areas, the least stress is the vertical which is the overburden pressure; the fracture will develop horizontally with injection pressure equal to or higher than the overburden pressure ‎[2]. the main objective of this study is determining the best empirical method that gives results of fracture pressure gradient approximated with the actual fracture pressure gradient derived from the previous studies and relied upon in drilling wells in this region. 2fracture pressure gradient estimation the technique that can be taken to calculate the fracture pressure for a specific formation is in two steps; https://doi.org/10.31699/ijcpe.2019.1.1 n. f. hussain and f. h. m. al mahdawi / iraqi journal of chemical and petroleum engineering 20,1 (2019) 1 7 2 the first one is called predictive methods which depend on the empirical equation and data from the previous drilled wells, the second step is the actual field data after drilled the well and complete the necessary tests to record the actual fracture gradient for that formation‎[1], ‎[3]. 2.1. predictive methods these methods required the estimation of the minimum stress value; according to terzaghi’s equation, the minimum effective stress value could be found from the following equation: (1) since the minimum stress ( is the required value, equation (3-12) could be written in term of it as follow: (2) to calculate the minimum stress for a specific formation, the value of which is the ratio of the effective stresses (horizontal to vertical) should be estimated. there are two methods for estimating: (1) using of poisson’s ratio (2) empirical methods ‎[4]. a. poisson’s ratio methods 1hubbert and willis method hubbert and willis method in fracture pressure gradient estimation depends on three variables: pore pressure, overburden stress, and poisson’s ratio. thus, hubbert and willis equation for estimating the fracture pressure gradient is as follow[2]: ( ) ( ) (3) in their method, they assumed a constant overburden gradient equal 1 psi/ft and constant poisson’s ratio equal 0.25; therefore, their equation will be the equation (4): ( ) (4) in geolog software[4], there are two options available:  input poisson’s ratio value manually (constant or curve).  bounds values (minimum 1/3 and maximum 1/2). if the second option is selected, a minimum and maximum fracture pressures gradient are estimated. 2cesaroni method cesaroni method estimated fracture pressure gradient depending on the mechanical behavior of rocks, and there are three formulas available ‎[5]:  for elastic rocks behavior with little or no mud filtrate because of rapid mud cake forming or low permeable formation, the differential pressure is totally supported by the borehole wall. the fracture pressure gradient is estimating by the following equation: ( ) ( ) (5)  for elastic rocks behavior with high mud filtrate invasion; the following equation is used: ( ) (6)  for plastic rocks behavior like shale, marl, and salt; the equation of fracture pressure gradient is: (7) 3eaton method eaton method for estimating fracture pressure gradient suggest the same equation of hubbert and willis method (equation (3)) but with variable poisson’s ratio modeled as a function of depth for deep gulf of mexico and shelf (shallow water) formations ‎[6]. 4daines method daines equation[7] is the same as eaton equation (eq. (3)) by adding superimposed tectonic stress term, the equation will be as follows ‎[7]: ( ) ( ) (8) daines suggested that the determination of from the first leak-off test while drilling and kept constant, the principle of the tectonic stress remaining constant in the entire well section. therefore; in geolog software[4] is a function of effective vertical stress and can be expressed as the following equation: (9) where: is daines tectonic stress factor, the final equation of daines’s method in geolog is as follow: ( ) ( ) (10) b. empirical methods 1matthews and kelly method mathews and kelly developed hubbert and willis method by using a variable stress ratio between the effective horizontal and vertical stresses, not a constant value of 1/3 ‎[8]. n. f. hussain and f. h. m. al mahdawi / iraqi journal of chemical and petroleum engineering 20,1 (2019) 1 7 3 to calculate a fracture gradient by this method one must use the following procedure:  estimate the formation pore pressure.  determine the effective stress. since, the overburden gradient is equal to 1 psi/ft as their assumption, therefore; the effective stress calculated from the following equation: (11)  determine the depth di which is the depth of the normal matrix stress from the following equation: (12)  determine from value and fig. 2.  calculate the fracture pressure gradient from matthews and kelly method using the following equation: ( ) ( ) (13) in geolog software [4], the overburden gradient could be calculated or put a fixed value equal 1psi/ft. fig. 2. matrix stress coefficient of matthews and kelly method ‎[8] 2christman method christman method in prediction fracture pressure gradient depends on the empirical estimation stress ratio ( ; thus, the fracture pressure gradient equation is ‎[9]: ( ) (14) in geolog, the stress ratio estimation is valid either from density log or water depth. 2.2. verification methods it is the actual value of fracture pressure for the next section obtained from the test at the casing shoe of the previous section after it had been cemented; the important of that test is to verify that the cement of casing and the formation below can endure the wellbore pressure required to complete drilling safely to the next target depth ‎[1]. formation integrity test (fit) is usually used to identify the fracture gradient for a specific formation; in fact, fit has more than meaning including:  limit test which is carried out to a specific point below the fracture pressure of that formation.  leak off test which is carried out to the point that the formation leak off.  formation breaks down test which is carried out to the point that the formation fracture.  fracture gradient test it is continue after the formation fracture, the importance of this test is to determine the minimum horizontal stress of earth. the full fit gives a complementary fracture data of the formation ‎[3]. 3area of cases study the area under study represent by halfaya oilfield; it was discovered since 1976 by well (hf-1). the structure was defined by 2d seismic data shot during 1976 and 1980. up to june 2010, eight wells were drilled by missan oil company (moc). the deepest well (hf-2) reached a depth of 4788m, down to the lower cretaceous sulaiy formation. significant oil accumulations have been discovered in multiple reservoirs of tertiary and cretaceous formations and the re-estimated initially oil in place is about 18.179 billion barrels in june 2017. the methods are applied by using logs and drilling data of hf010-n010. 4calculations the general fracture pressure gradient equation required two inputs which are overburden pressure gradient and pore pressure gradient; the overburden pressure gradient is the pressure exerted, on a specific point, by the total weight of both the rock’s grains and fluids within the pores. the density of the combination is called the bulk density ( ). the overburden pressure gradient varies with depth because of the variations of formation density; this is a result of the variations in the types of rocks, the densities of fluids, and the compaction degree of rocks ‎[11]. n. f. hussain and f. h. m. al mahdawi / iraqi journal of chemical and petroleum engineering 20,1 (2019) 1 7 4 fig. 3. hf010-n010 location in the top of nahr umr b structural map, halfaya oilfield ‎[10]. in geolog software[4], the overburden pressure module computes overburden pressure from integrating bulk density log values over depth by the following equation: ∫ (15) where the water pressure is used for only offshore situation, and the 0.4334 factor is used for converting density (g/cc) to pressure, air pressure is calculated in an onshore situation using equation (16). ( ) (16) the pore pressure gradient is estimated by eaton’s method using dc-exponent data as the following equation ‎[12]: * ( ) + ( ) (17) if density log information is not available for all intervals, it is often estimated from sonic transit time (pwave velocity); in ip software there are three methodologies those of gardner ‎[13] bellotti et al ‎[14] and lindseth ‎[14] and the following equations represent these methods respectively: (18) where: a and b are constants (19) (20) where, eq. (19) is for consolidated formations and eq. (20) for unconsolidated formations. (21) overburden gradient could be calculated for any point by dividing the overburden pressure of this point by its depth. the poisson’s ratio can be measured in laboratory either by dynamic method using pules velocities of longitudinal and shear waves which are called the indirect method or directly by static method ‎[16]; if the core sample is not available for a specific interval, it can be calculated either from velocities, vpvs ratio, or using moduli (bulk modulus and shear modulus). geolog software provides the possibility of estimating it from compressional transit time ( ), shear transit time ( s), and bulk density ( ). then the following equation is used in calculation ‎[4]: (22) n. f. hussain and f. h. m. al mahdawi / iraqi journal of chemical and petroleum engineering 20,1 (2019) 1 7 5 when ∆ts data is not available for a specific depth, it could be estimated from compressional transit time using the greenberg-castagna empirical relationships for different minerals in ip software as follow ‎[17]: (23) where: a, b, and c are constants depending on the lithology of the intervals. 5results the methods result approximately match the results of the previous study (field development plan revision no.1 of halfaya contract area, iraq/ by petrochina company for missan oil company) ‎[10] which have been relied upon in drilling the previous wells, the results are inserted in fig. 4 and fig. 5. fig. 4. comparison between methods selected to estimate the fracture pressure gradient in hafaya oilfield fig. 4 shows that, as the comparison with the actual fracture pressure gradient ( a study by petrochina company for missan oil company[10] which is current practice in the oilfield, the green curve), hubbert and willis method which is the orange curve gives the lowest value, the results of daines method ( the brown curve) and mathews and kelly method are low, the results of eaton and christman methods at the deepest formations (about 2000 m and deeper) are given a good match, and cesaroni i which is represented by equation (5) is given the best match for all formations. fig. 5. hydrostatic, overburden, pore and fracture pressures and their gradients of halfaya oilfield (hf010n010) (fracture pressure gradient by cesaroni i). in fig. 5, the pore pressure gradient (the green curve) is estimated by eaton method using dc-exponent data and the fracture pressure gradient (the purple curve) is estimated empirically using cesaroni i method which gives a good match as mentioned in figure (4); and the results fracture pressure gradient for halfaya oilfield are summarized as follow:  the fracture pressure gradient of upper fars formation ranges (0.9-1.0) psi/ft.  the fracture pressure gradient of lower fars formation is equal (1.0) psi/ft  fracture pressure gradients of upper kirkuk, middle kirkuk, and lower kirkuk are equal (0.95) psi/ft.  the fracture pressure gradient of jaddala formation reduces to (0.85) psi/ft; since it is an abnormally lowpressure formation.  the fracture pressure gradient of the deepest formations (shiranish, hartha, tanuma, khasib, mishrif, rumaila, ahmadi, mauddud, and nahr umr) ranges (0.80.9) psi/ft. 6discussion the best method in estimating fracture pressure gradient to avoid problems develop in a formation and design an optimal drilling fluid program with right casing seat is that the leak-off test which is the only one that gives an exact value of the fracture pressure gradient. however, for economic reasons the empirical methods are the alternative selection, every method have a weak point must be taken into account and they are summarized as follow: n. f. hussain and f. h. m. al mahdawi / iraqi journal of chemical and petroleum engineering 20,1 (2019) 1 7 6  hubbert and willis's method imposes a constant overburden pressure gradient and constant poisson’s ratio and these assumptions are inaccurate, the overburden pressure gradient showed in figure (5) is vary and increase with depth; also, poisson’s ratio depends on the type of rocks in the formations; so that, it gave incorrect results as compared with the actual fracture pressure gradient.  matthews and kelly method suggest a constant overburden pressure gradient equal (1.0) psi/ft which is the same assumption as hubbert and willis method and this method is not applicable in abnormal high pressure formations because the stress ratio used in formations with high pore pressure is equal the normal pore pressure in deepest depth and in this area (halfaya oilfield) we have an abnormally highpressure formations such as lower fars and mishrif formations as shown in fig. 5.  christman method depends on empirical techniques in estimating stress ratio which adds a percentage of inaccuracy.  the tectonic stress factor in daines method is assumed.  in eaton’s method, poisson’s ratio modeled as a function of depth for deep gulf of mexico and shelf (shallow water) formations and it may be equivalent to the formation under study or not. 7conclusions in this work, the methods of huubert and willis, cesaroni i, cesaroni ii, cesaroni iii, eaton, and daines were selected. also, poisson’s ratio was considered crucial and the empirical methods selected are matthews and kelly and christman. the following conclusions were driven from the study: 1cesaroni i give the best results of the fracture pressure gradient in halfaya oilfield as the comparison with previous field study (field development plan revision no.1 of halfaya contract area, iraq/ by petrochina company for missan oil company). 2the fracture pressure gradient is directly proportional to the pore pressure gradient. nomenclature symbols description unit air press air pressure psi d depth m d drilling exponent dc correct drilling exponent dcn normal dc dco observed dc mean sea level depth m depth of normal matrix stress ft elevation of measurement reference m gr gamma ray gapi the ratio of horizontal effective stress to vertical effective stress matthews and kelly matrix stress coefficient p pore pressure psi fracture pressure psi hydrostatic pressure psi water pressure gradient psi/ft s in-situ stress psi minimum in-situ stress psi elevation of drilling surface m compressional velocity ft/us shear velocity ft/us water press water pressure psi greek symbols description unit vertical stress (overburden pressure) psi horizontal effective stress in x direction psi horizontal effective stress in y direction psi vertical effective stress psi minimum effective stress psi superimposed tectonic stress psi poisson’s ratio sonic compressional transit time us/ft shear transit time us/ft tectonic stress factor bulk density of rock gm/cc references [1] a. bourgoyne jr., k. millheim, m. chenevert, and f. young jr., “formation pore pressure and fracture resistance,” in applied drilling engineering, 1986, pp. 246–299. [2] m. hubbert and d. willis, “mechanics of hydraulic fracturing,” j. pet. technol., vol. 9, no. 6, pp. 153– 168, 1957. [3] h. rabia, “formation integrity test,” in surface well control theory and equipment, 2017, pp. 181–204. [4] paradigm, “geolog 7.4 pore pressure prediction user guide,” paradig. 15.5, united states 2015. [5] r. cesaroni, d. giacca, e. possamai, and a. schenato, “experience in overpressure detection and evaluation in the mediterranean offshore,” ieoc, cairo, 1982. [6] b. a. eaton, “fracture gradient prediction and its application in oilfield operations,” j. pet. technol., vol. 21, no. 10, pp. 1353–1360, 1969. [7] s. r. daines, “prediction of fracture pressures for wildcat wells,” j. pet. technol., vol. 34, no. 4, pp. 863–872, 1982. [8] w. matthews and j. kelly, “how to predict formation pressure and fracture gradient,” oil gas j., 1967. [9] s. a. christman, “offshore fracture gradients,” j. pet. technol., vol. 25, no. 08, pp. 910–914, 1973. [10] petrochina (halfaya), “field development plan revesion no.1 of halfaya contract area, iraq,” missan, 2017. [11] h. rabia, “wellbore pressure,” in surface well control theory and equipment, 2017, pp. 9–64. [12] b. a. eaton, “the equation for geopressure prediction from well logs,” fall meet. soc. pet. eng. aime, 1975. https://www.osti.gov/biblio/7004890 https://www.osti.gov/biblio/7004890 https://www.osti.gov/biblio/7004890 https://www.osti.gov/biblio/7004890 https://www.ems.psu.edu/~radovic/eme580_t1_sci1.pdf https://www.ems.psu.edu/~radovic/eme580_t1_sci1.pdf https://www.ems.psu.edu/~radovic/eme580_t1_sci1.pdf https://www.onepetro.org/journal-paper/spe-2163-pa https://www.onepetro.org/journal-paper/spe-2163-pa https://www.onepetro.org/journal-paper/spe-2163-pa https://www.onepetro.org/general/spe-9081-ms https://www.onepetro.org/general/spe-9081-ms https://www.onepetro.org/general/spe-9081-ms https://ci.nii.ac.jp/naid/10019750703/ https://ci.nii.ac.jp/naid/10019750703/ https://www.onepetro.org/conference-paper/spe-5544-ms https://www.onepetro.org/conference-paper/spe-5544-ms https://www.onepetro.org/conference-paper/spe-5544-ms n. f. hussain and f. h. m. al mahdawi / iraqi journal of chemical and petroleum engineering 20,1 (2019) 1 7 7 [13] g. l. f. gardner, l. w. gardner, and a. r. gregory, “formation velocity and density,” in the diagnostic basics for stratigraphic traps geophysics 39, 1974, pp. 770–780. [14] p. bellotti, v. di lorenzo, and d. giacca, “overburden gradient from sonic log trans,” spwla, london, march, 1979. [15] r. o. lindseth, “synthetic sonic logs – a process for stratigraphic interpretation,” geophysics, vol. 44, no. 1, pp. 3–26, 1979. [16] h. ã. gercek, “poisson’s ratio values for rocks,” int. j. rock mech. min. sci., vol. 44, pp. 1– 13, 2007. [17] m. l. greenberg and j. p. castagna, “shearwave velocity estimation in porous rocks: theoretical formulation, preliminary verification and applications,” geophys. prospect., vol. 40, no. 2, pp. 195–209, 1992. التنبؤ بتدرج ضغط التكسير في حقل حمفايه النفط الخالصة عمال مكماًل في تصميم البئر ويجب أن يؤخذ بنظر االعتبار عند وتقدير تدرج ضغط التكسير يعتبر التنبؤ اختيار وزن طين الحفر اآلمن وتصميم األسمنت وتحديد مقعد التغميف األمثل لتقميل مشاكل الحفر الشائعة. leak-off test قيمة التدرج الدقيق لمكسر الناتجة من الفحوصات التي تجرى عمى البئر أثناء الحفر مثل ،formation integrity test ،cement squeeze ، الخ ؛ ومع ذلك ، لتقميل التكمفة اإلجمالية لمحفر ... ىناك عدة طرق يمكن استخداميا لحساب تدرج ضغط الكسر المصنفة في مجموعتين: األولى تعتمد عمى نسبة huubert and ق المختارة ىيبواسون لمصخور والثانية ىي طرق تجريبية بالكامل. في ىذا البحث ، الطر willis, cesaroni i,: cesaroni ii, cesaroni iii, eaton, and daines حيث تعتبر نسبة بوايسون وتعطي نتائج ىذه christman و matthews & kellyضرورية ىنا واألساليب التجريبية المختارة ىي الطرق تطابًقا تقريًبا مع الدراسة الميدانية السابقة التي تم االعتماد عمييا في حفر اآلبار السابقة في الحقل وتم في الطبقات ذات االعماق بصوره عام لتكون المعادلة التي تمثل الحقل تحت الدراسو cesaroni iاختيار , eatonل ؛ بينما في الطبقات العميقو فإن كل من طريقة ىي االفض cesaroni iالضحمو ، ان طريقة christman و ,cesaronii تعطي تطابق جيد ومتقارب. ان تدرج ضغط التكسير في حقل حمفايو النفطي .psi/ft( 3.81و 0..8يتراوح بين ) https://library.seg.org/doi/abs/10.1190/1.1440465 https://library.seg.org/doi/abs/10.1190/1.1440465 https://library.seg.org/doi/abs/10.1190/1.1440465 https://library.seg.org/doi/abs/10.1190/1.1440465 https://library.seg.org/doi/abs/10.1190/1.1440922 https://library.seg.org/doi/abs/10.1190/1.1440922 https://library.seg.org/doi/abs/10.1190/1.1440922 https://www.sciencedirect.com/science/article/pii/s136516090600075x https://www.sciencedirect.com/science/article/pii/s136516090600075x https://www.sciencedirect.com/science/article/pii/s136516090600075x https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2478.1992.tb00371.x https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2478.1992.tb00371.x https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2478.1992.tb00371.x https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2478.1992.tb00371.x https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2478.1992.tb00371.x iraqi journal of chemical and petroleum engineering vol.15 no.2 (june 2014) 6173 issn: 1997-4884 formulation of new equation to estimate productivity index of horizontal wells ghanim m. farman and maha raouf abdulamir college of engineering university of baghdad abstract significant advances in horizontal well drilling technology have been made in recent years. the conventional productivity equations for single phase flowing at steady state conditions have been used and solved using microsoft excel for various reservoir properties and different horizontal well lengths. the deviation between the actual field data, and that obtained by the software based on conventional equations have been adjusted to introduce some parameters inserted in the conventional equation. the new formula for calculating flow efficiency was derived and applied with the best proposed values of coefficients ψ=0.7 and ω= 1.4. the simulated results fitted the field data. various reservoir and field parameters including lateral horizontal length of the horizontal well (l), skin factor (s), ratio of the vertical to horizontal permeability of the formation (kv/kh), and the vertical thickness of the productive zone (h) were studied and verified to generalize the suggested equation to estimate the horizontal well productivity indices for various reservoir kinds. this led to creating a new formula of flow efficiency equation that could be applied in ahdeb field. keywords: productivity index, ahdab oil field, horizontal well, horizontal well length introduction throughout the last decade, horizontal well technology ruled the oil and gas industry with growing success worldwide. it has now been a widely accepted approach for hydrocarbon recovery optimization. the post implementation recovery, in most cases, has been exceptional with the achievement of the following general goals [1]: a) reduction of exploitation time by increasing the production rate and thereby improving the cash flow and rate of return on investment. b) improving recovery by reaching the by-passed area in an effective way and increasing the drainage area. the actual productivity of a horizontal well depends on many reservoir and well parameters such as kv/kh, reservoir thickness, drainage area, fracture patterns and intensity, horizontal well length, etc. [3]. numerous models are available in the literature to predict the productivity of horizontal wells. these models are applicable directly only to single phase systems and in reservoirs under "steady state" and "pseudo steady state". iraqi journal of chemical and petroleum engineering university of baghdad college of engineering formulation new equation to estimate productivity index of horizontal wells 62 ijcpe vol.15 no.2 (june 2014) -available online at: www.iasj.net the performance of a horizontal well can be strongly influenced by the anisotropy of horizontal to vertical permeability. thus, modeling of a horizontal well is much more complex than modeling a vertical well. there are basically two categories of methods for calculation of horizontal well productivity: analytical and semianalytical models. borisov [4] developed one of the earliest analytical models for calculating steady state oil production from a horizontal well. the horizontal flow was assumed from an equivalent circular drainage area toward a vertical fracture with drainage radius much larger than the vertical fracture length; he presented the equation below: ( e ) ( ) ( ) …(1) where reh is the drainage radius of the horizontal well. giger [5] proposed a model similar to borisov’s, but assumed an ellipsoidal drainage area, ( √ ⁄ ) ( ) ...(2) karcher, giger, and combe [6] summarized the existing productivityprediction models, and addressed the limiting assumptions and applicability of each model. joshi [7] developed a model with elliptical flow in the horizontal plane and radial flow in the vertical plane. the model was modified to take into account the influence of the horizontal well eccentricity from the vertical center of reservoir and the anisotropy of horizontal to vertical permeability, [ √ ⁄ ⁄ ] [ ] ...(3) where a is the semi-major axis of the drainage ellipse, ( ) √ ( ⁄ ) for …(4) and β is the permeability anisotropic factor √ ...(5) economides et al. [8] augmented the joshi’s equation ith peaceman’s equivalent wellbore radius in an anisotropic formation: y ⁄ y ⁄ ...(6) which, ith the β variable, becomes √ …(7) also, according to peaceman’s transformation, the equivalent vertical height must be: eq √ …(8) all these expressions are based on muskat’s [9] original work on permeability anisotropy. thus, the second logarithmic expression in the denominator of joshi’s equation must be: eq ...(9) and therefore, more appropriate expression for horizontal well inflow is: [ √ ⁄ ⁄ ] [ ] …(10) ghanim m. farman and maha raouf abdulamir -available online at: www.iasj.net ijcpe vol.15 no.2 (june 2014) 63 which for β=1 reverts e actly the joshi’s equation. renard and dupuy [10] modified the steady state equation to include the effective wellbore radius: ( ) ( ) ...(11) where x=2a/l, a is the same as state in eq. 4; cosh -1 (x) is the invers hyperbolic cosine function, and effective wellbore radius is: ( ) …(12) later, a number of models, both analytical and semi-analytical, were developed using the source function method. the well drainage area was assumed to be a parallelepiped or infinite with no-flow or constant pressure boundaries at top, bottom and the sides. in general, the analytical models are asymptotic solutions under some appropriate simplifications and specific conditions, while the semianalytical models are rigorous solutions of the original boundary value problem but have to be solved numerically. formulation of the proposed equations estimation of productivity index in horizontal well is directly affected by two key parameters which determine flow direction toward the horizontal well. joshi [7] developed a widely accepted equation to estimate steady state productivity from a horizontal well. he introduced horizontal and vertical resistances in the arcy’s flo equation and gave the following relationship: ...(13) where α=kh/µb and rhp and rvp are horizontal and vertical resistance’s to flow. to simplify the mathematical analysis of the three-dimensional (3d) problem, joshi [7] subdivided it into two twodimensional (2d) problems; see figure1. fig. 1: division of 3d horizontal-well problem into 2d problems [7] the total flow into the horizontal well is having the following components: 1.) flow into a horizontal well in a horizontal plane. the pressure at the drainage boundary pe is: [ √ ] …(14) formulation new equation to estimate productivity index of horizontal wells 64 ijcpe vol.15 no.2 (june 2014) -available online at: www.iasj.net the pressure drop between the drainage boundary and ell δp is the same as pe defined in eq. 14 because wellbore pressure is assumed to be zero. substituting this into darcy's porous-medium equation, we can show it to be: ⁄ [ √ ] …(15) here δr is the ell half-length (l/2). ⁄ [ √ ⁄ ⁄ ] …(16) eq. 16 represents flow to a horizontal well from a horizontal plane. to calculate horizontal-well drainage radius, reh, areas of a circle and ellipse (in a horizontal plane, fig. 2) are equated. this reduces to: √ …(17) where a and b are major and minor axes of a drainage ellipse. moreover, +l/2 and –l/2 represent foci of a drainage ellipse. hence, using properties of an ellipse, we can show that: √ ⁄ …(18) using an electrical analog concept, flow resistance in a horizontal direction is given as: [ √ ⁄ ⁄ ] …(19) fig. 2: schematic potential flow to a horizontal well: horizontal plane and vertical plane [3] 2.) flow into a horizontal well in a vertical plane. darcy's equation for flow through a porous medium to a vertical well is: ...(20) in this equation, the term in the denominator refers to horizontal flow. flow in a horizontal well is the same as flow in a vertical well rotated ninety degree. we can state that re for vertical well is equivalent to h/2 for a horizontal well. after replacing re by h/2 into eq. 20, it yields: ⁄ ...(21) the influence of vertical flow in horizontal wells is closely linked to relation between reservoir thickness and wellbore length, h/l, which means, the lower h/l is, the lower the influence of this type of flow is. applying this concept to eq. 21, we obtain: ghanim m. farman and maha raouf abdulamir -available online at: www.iasj.net ijcpe vol.15 no.2 (june 2014) 65 ⁄ …(22) the vertical-resistance term represents resistance in a vertical plane in a circular area of radius h/2 around the wellbore which is: [ ] …(23) part of this resistance is already accounted for in the horizontal resistance term . different methods of combining and were considered to calculate effective flow resistance. horizontal and vertical resistances were added to calculate horizontal-well oil production: ( ) …(24) and { [ √ ⁄ ⁄ ] [ ]} for l>h and l/2˂ 0.9 reh …(25) where a, half the major axis of a drainage ellipse in a horizontal plane in which the well is located fig. 2, is obtained as shown below: ( ) [ √ ( ⁄ ) ] …(26) the above relationships were developed for isotropic reservoirs ( ). in many reservoirs, the vertical permeability is less than the horizontal permeability. in really anisotropic reservoirs, it is possible to have a higher vertical permeability than the effective horizontal permeability. for a horizontal well, a decrease in vertical permeability results in an increase in vertical-flow resistance and a decrease in oil production rates. as muskat [9] showed, the reservoir anisotropy could be accounted for by modifying the vertical axis as √ ⁄ and the average reservoir permeability as √ . the modification of the z axis makes the wellbore elliptic. if the elliptic wellbore effects are assumed to be negligible, eq. 25 is modified to account for the reservoir anisotropy: { [ √ ⁄ ⁄ ] [ ]} for l>βh and l/2˂ 0.9 reh …(27) where √ ⁄ in eq. 27, the variable β, hich is the measure of reservoir permeability anisotropy [i.e., (kh/kv) 1/2 ] is particularly important. obviously, the smaller β is, the larger the inflow performance of a horizontal well is. economides et al. [8] augmented the joshi’s [7] equation, with peaceman's equivalent wellbore radius in an anisotropic formation: y ⁄ y ⁄ …(28) this, ith the β variable, becomes: √ ...(29) also, according to peaceman’s transformation, the equivalent vertical height must be: eq √ …(30) all these expressions are based on muskat’s [9] original ork on permeability anisotropy. thus, the second logarithmic expression in the denominator of joshi’s equation, eq. 27, must be: formulation new equation to estimate productivity index of horizontal wells 66 ijcpe vol.15 no.2 (june 2014) -available online at: www.iasj.net eq …(31) and therefore, more appropriate expression for horizontal well inflow developed by economides et al. [8] is: { [ √ ⁄ ⁄ ] [ ]} …(32) which for β=1 reverts e actly the joshi’s equation, eq. 27. there are two terms in the denominator of eq. 32. the first one (left-hand side) responds for flow in the horizontal direction and the second one is responsible for flow in the vertical direction that can be seen in any of the productivity index correlations (eqs. (borisov) [4], (giger) [5], (joshi) [7] and (renared and dupuy) [10]). the flow towards horizontal well has been verified for different dependent parameters; the results were compared with the actual well productivity for ahdeb field. we found that the horizontal flow factor proposed by economides et al. is the same as the one in josh’s correlation. therefore, we took the correlation factor proposed by economides et al. to represent this type of flow. it can be concluded a new adjustment for the weighting coefficient that should be done to fit the result of economides et al. with actual data. thus: { ( [ √ ⁄ ⁄ ]) [ ]} ... .(33) where ψ and ω are constants (weighting coefficients), which will be determined by using a trial and error procedure. where fd is the unit conversion factor. in field units, fd=0.001127; in metric units, fd=86.4. impact of skin effect on horizontal well performance the horizontal well skin effect is added to the denominator of eq. 33, ith multiplied it by ωβh/l, and the anisotropic scaled aspect ratio is called in the following manner: { ( [ √ ⁄ ⁄ ]) [ [ ] ]} …(34) the skin effect, denoted as s, is the characteristic of the shape of damage in horizontal wells, taking into account the permeability anisotropy and the likelihood of larger damage penetration near the vertical section. the productivity index, jh, for the horizontal well can be estimated by dividing qh by δp as follo s: { ( [ √ ⁄ ⁄ ]) [ [ ] ]} …(35) different to other correlations, this correlation includes t o constants, ψ and ω, to allo an optimum match with respect to the simulated results. using a trial and error procedure [11], the values of constants ψ and ω in eq. 35 were determined at the lowest deviation error with the simulated results attained. these values were found to be ψ=0.7 and ω= 1.4; eq. 35 has been arranged to involve (ψ=0.7), (ω= 1.4) and (fd=0.001127) to fit the field results and yield the following equation: { ( [ √ ⁄ ⁄ ]) [ [ ] ]} …(36) the simple excel spreadsheet program was developed to calculate the productivity values of horizontal wells using three major available productivity equations. these ghanim m. farman and maha raouf abdulamir -available online at: www.iasj.net ijcpe vol.15 no.2 (june 2014) 67 equations include: joshi [7] equation 3, economides et al. [8] equation 10 and renard and dupuy [10] equation 11. also, the developed spreadsheet program was used to compute the productivity index employing the improved equation, eq. 34. the stimulated results obtained using fast welltest software is also presented. it can be noticed that the productivity index of horizontal well is mainly the function of six parameters of the reservoir: horizontal length (l), anisotropy factor (β), formation thickness (h), drainage radius (re), well radius (rw) and skin factor (s). to develop a general equation for estimation horizontal well productivity index, various parameter reservoir properties have been made to assist to generate eq. 36 which can be used to estimate horizontal well productivity index for ahdeb or any other field. effect of horizontal well length (l) the improved equation and the stimulated results are used to study the effect of horizontal well length on productivity index of horizontal well for a wide range of horizontal well length in the range of 250 to 6000 ft, as shown in figures 3 to 11. figures 3 to 11 show that the modified equation gives extremely exact results with that obtained from ahdeb field. while original equation and other selected equations give biggest deviation from the field data. this conclusion has been proved for all parameters affecting horizontal well productivity index as shown in figures 3 to 11. the results of all equations show that horizontal well productivity increases as well length increases. fig. 3: effect of well length on pi of hw for (s=0) and (kv/kh=2) formulation new equation to estimate productivity index of horizontal wells 68 ijcpe vol.15 no.2 (june 2014) -available online at: www.iasj.net fig. 4: effect of well length on pi of hw for (s=+3) and (kv/kh=2) fig. 5: effect of well length on pi of hw for (s=-3) and (kv/kh=2) ghanim m. farman and maha raouf abdulamir -available online at: www.iasj.net ijcpe vol.15 no.2 (june 2014) 69 fig. 6: effect of well length on pi of hw for (s=0) and (kv/kh=1) fig. 7: effect of well length on pi of hw for (s=3) and (kv/kh=1) formulation new equation to estimate productivity index of horizontal wells 70 ijcpe vol.15 no.2 (june 2014) -available online at: www.iasj.net fig. 8: effect of well length on pi of hw for (s=-3) and (kv/kh=1) fig. 9: effect of well length on pi of hw for (s=0) and (kv/kh=0.5) ghanim m. farman and maha raouf abdulamir -available online at: www.iasj.net ijcpe vol.15 no.2 (june 2014) 71 fig. 10: effect of well length on pi of hw for (s=3) and (kv/kh=0.5) fig. 11: effect of well length on pi of hw for (s=-3) and (kv/kh =0.5) brief description of the field ahdeb oil field is located between nomina town and kut town of wasit province, 180km southeast away from baghdad. the ahdeb oil field is an anticline elongated trending nww-see. there are three heights which are ad-1, ad2, and ad-4 within the anticline. based on testing data, the main oilbearing formations in the ahdeb formulation new equation to estimate productivity index of horizontal wells 72 ijcpe vol.15 no.2 (june 2014) -available online at: www.iasj.net field are khasib formation of upper cretaceous, mishrif, rumaila and mauddud formations of middle cretaceous. the cover depth of the oil reservoirs is from 2600m to 3300m. horizontally, the oil-bearing formations of khasib is distributed all over the field, the oil-bearing formations of mishrif, rumaila and mauddud mainly are distributed in the eastern part. the average core porosity is 17.3%; the average permeability is 25 md. the ahdeb reservoirs have moderate porosity with lower permeability. pressure coefficient is 1.135 averagely. reservoir temperature is 71-85 ℃. conclusions 1. a new formula for calculating flow efficiency is derived and applied in ahdeb field. this equation takes into consideration the proposed values of ψ=0.7 and ω= 1.4. 2. the factors (well length, permeability ratio, reservoir thickness, skin factor, drainage radius, and well radius) affect the pressure drop between the wellbore and the reservoir affect productivity index in horizontal wells. 3. the productivity index of horizontal well results obtained for well ad10-h show very close agreement with other results obtained for other wells drilled by chinese company. 4. the simulation of ahdeb field indicates that the reservoir is affected by the existence of a partial edge water drive. this conclusion agreed also with that of the chinese company. 5. the horizontal well productivity index is highly affected by the lateral horizontal well section and the net pay thickness of the reservoir. since studying the net, production thickness for each well is very important to estimate the horizontal well productivity index. recommendations 1. prediction of the reservoir performance when the reservoir pressure declines below the bubble point pressure and multiphase flow of fluid is an important future case of study. 2. a study of water and gas injection to increase the productivity of horizontal wells can be taken into consideration. 3. a study of forecast for the horizontal well productivity index of previous drilled wells in ahdeb oil field is important to maximize the production of the field. 4. for reservoirs with small vertical permeability value, kv can be increased by fracturing the reservoirs to reduce the anisotropy value and as a result increasing horizontal well productivity idex. nomenclature a = drainage area, acres a = semi-major axis of the drainage ellipse, (ft), (m) bo = oil formation volume factor (bbl/stb) fd = unit conversion factor. in field units (0.001127); and in metric units (86.4). h = formation thickness (ft), (m) j = productivity index (stb/d/psi) jh = oil productivity index for horizontal well (stb/d/psi) k = permeability (millidarcy) kh = horizontal permeability (millidarcy) kv= vertical permeability (millidarcy) l = horizontal lateral length, ft q = flow rate, (stb/d) qh = flow rate for horizontal well, (stb/d) qv = flow rate for vertical well, (stb/d) p = pressure, (psi) = bubble point pressure, (psi) = bounded pressure (psi) = reservoir pressure (psi) ghanim m. farman and maha raouf abdulamir -available online at: www.iasj.net ijcpe vol.15 no.2 (june 2014) 73 = bottom hole flowing pressure (psi) re = drainage radius (ft), (m) reh = drainage radius for horizontal well (ft), (m) rev = drainage radius for vertical well (ft), (m) rw = wellbore radius (ft), (m) s = skin factor (dimensionless) stb =stock tank barrel β = anisotropy ratio (√ ⁄ ) o = oil viscosity, (cp) ø = porosity (percentage) references 1joshi, s.d.: "horizontal well technology ", penn. well publishing company, tulsa, ok, u.s.a., 1991. 2fdp study of ahdeb oilfield, iraqreservoir engineeringcnpc science and technology research institute. june, 2011. 3joshi, s.d.: "horizontal well productivity", 2009. 4borisov, j., p., (1964): “oil production using horizontal and multipleeviation wells”, moskva, nedra, 1964. 5giger, f., m. (1986): “the reservoir engineering aspects of orizontal rilling”, spe paper 13024. 6kuchuk, f., j., goode, p.a, brice, b. w., and sherrard, d., w., (1988b): “pressure transient analysis and inflow performance for orizontal wells”, spe paper 18300, presented at the 63rd annual spe conference, houston, texas oct. 2-5. 7 joshi, s. d. (1988): "augmentation of well productivity using slant and horizontal wells", journal of petroleum technology, p 729. 8 economides, m. j., “comprehensive simulation of orizontal well performance” spe 20717, 1990. 9muskat, m.: the flow of homogeneous fluids through porous media, mcgraw-hill book co. inc., new york city (1937). 10g. renard and j.m. dupuy, (1991): “formation damage effects on horizontal well flow efficiency” paper spe 19414. 11ghanim m. farman “study of the flow efficiency of horizontal wells in a eb oil field” dissertation submitted to the college of engineering university of baghdad in partial fulfillment of the requirements for the degree of doctor of philosophy in petroleum engineering. iraqi journal of chemical and petroleum engineering vol.16 no.4 (december 2015) 6778 issn: 1997-4884 simulation the radiation zone of al-mussaib power plant by using monte carlo method tahseen ali al-hattab * , ali abd al-muhsen al-assady ** and wisam ahmed abd alwahid *** * university of babylon, ** university of baghdad, *** university of kufa abstract the temperature distributions are to be evaluated for the furnace of al-mussaib power plant. monte carlo simulation procedure is used to evaluate the radiation heat transfer inside the furnace, where the radiative transfer is the most important process occurring there. weighted sum of gray-gases model is used to evaluate the radiative properties of the non gray gas in the enclosure. the energy balance equations are applied for each gas, and surface zones, and by solving these equations, both the temperature, and the heat flux are found. good degree of accuracy has been obtained, when comparing the results obtained by the simulation with the data of the designing company, and the data obtained by the zonal method. in the above work, a code of monte carlo method is built, and used to overcome the mathematical analysis. key words: temperature distributions, degree of accuracy introduction the representation of the heat transfer processes, inside the industrial furnaces, have taken a very big attention in the literatures, where in the past two simplified cases are used, the well stirred enclosure which assume perfectly mixed combustion products, and the long furnace model which assume plug flow of combustion products with no radial temperature gradient. in order to predict the accurate temperature distribution in the enclosure, the zone method have been developed. because that the zone method can deal only with furnaces of simple shapes, and that it is suffering from a lack to evaluate the total exchange area between zones can not see each other, monte carlo method introduced as a solution for this problem. monte carlo method was first reported in 1964 [1], and the text book by siegel, and howell [2] presented the fundamental concepts of the method, and some examples analyzing simple systems. all the later literatures using monte carlo method are based on the same concepts with very much modification to the method to represent the conditions of the problem. there are many studies which studying the radiative transfer inside furnaces, but a few studies selected and presented here, which show the application of the method on furnaces, where vercammen, and iraqi journal of chemical and petroleum engineering university of baghdad college of engineering simulation the radiation zone of al-mussaib power plant by using monte carlo method 68 ijcpe vol.16 no.4 (dec. 2015) -available online at: www.iasj.net froment [3], introduce an improvement to the zone method, where the concepts of the method still the same, but the total exchange areas among the zones are obtained by monte carlo method. steward, and guruz [4] apply monte carlo method to evaluate the total exchange area among zones of an industrial furnace, with a non gray medium contains a particle radiation, and by neglecting the scatter. gupta, wall, and true love [5] apply monte carlo method to a cylindrical furnace, both isotropic, and anisotropic scattering mediums are examined. taniguchi, kudo, and sasaki [6], apply monte carlo method to study two kinds of furnaces, with two, and three dimensional radiative analysis, both luminous, and non luminous flames are studied in the furnaces. system description the furnace under consideration is the boiler of al-mussaib power plant, which is a babcock and wilcox radiant boiler. the combustion chamber is approximately 20m in height, 13m in width, and 11m in length. steady state energy equations after dividing the system into (154) surface zones, and (116) volume zones, each zone will be assumed small enough to consider as isothermal. then, the steady state energy equation is applied to each zone, to evaluate the temperature, and heat flux distributions, after solving them simultaneously: infhinroutfcgoutr qqqqqq ,,,,  … (1) cinrdsoutr qqqq  ,, … (2) where, equation (1) is applied to volume zones, and equation (2) is applied to surface zones. the term qr refers to radiative heat transfer, qc is convective heat transfer, qf is advective heat transfer, qh is heat generation, and qd is the heat flux at the surface elements. the terms of equations (1), and (2) can be obtained from: vtkq ggoutr 4 , 4  … (3) atq ssoutr 4 ,  … (4) soutrgoutrinr qsxqgxq ,,,   … (5)   sgc tthaq  ... (6) upgppginf tcvmq ,,  … (7) gpgoutf tcmq  , … (8) the total exchange area, in the present work, will be obtained by monte carlo method. monte carlo method monte carlo method is a statistical procedure, which simulates the radiation events (absorption, and emission), in terms of random numbers distributed in the range (0-1). in this method, and for each zone, a finite number of energy bundles will be defined, every bundle emitted from the zone will be governed by the azimuthal angle υ, and the polar angle θ, which are given by 1 2 r  … (9)  zonessurfaceforr 2 cos  …(10)  zonesgasforr 3 21cos  … (11) tahseen ali al-hattab, ali abd al-muhsen al-assady and wisam ahmed abd al-wahid -available online at: www.iasj.net ijcpe vol.16 no.4 (dec. 2015) 69 the probable mean free path is given by:   n rkl ln1 … (12) if the bundle traveled the mean free length (1) and it was less than the maximum path (l), the bundle will not be intercepted by wall, then the bundle is said to be absorbed by the gas, and tally there, if not, another condition applied, which is 5 r … (13) if the above condition is applied, then the bundle is said to be absorbed by the surface, and the bundle is tallied there, and if the condition is not satisfied, then the bundle is said to be reflected, and the point of reflection will be treated as emission point, previous procedure will be repeated for the new emission point. this procedure is repeated for each bundle till all the history of bundles is tallied. this procedure can be represented by figure (l). the total exchange area can be evaluated for each zone, by dividing the number of bundles reached to each zone, by the total number of bundles emitted. evaluation of the radiative properties of the non gray gas the gas fills the boiler will be assumed as non gray gas, and the weighted sum of gray gases model will be used to evaluate the total emissivity, and total absorptivity for each zone according to that zone temperature. total emissivity for the weighted sum of gray gases model is evaluated from the following expression   kips l i i eta     1 0 , … (14) the weighting factor for i=0, is evaluated from:    l i i aa 1 ,0, 1  … (15) a convenient representation of the temperature dependency of the weighting factors is a polynomial of order j-l given as follows: 1 1 ,,,    j j j jii tba  … (16) where bε,i,j can be evaluated from the data of appendix (a). to evaluate the total absorptivity, the irradiation temperature of surface surrounding the gas is also introduced. hence:   kips s l i i etta     1, 0 , … (17) where 1 1 1 1 ,,,,              j j j k k k skjii ttca  … (18) again the value of kji c ,,, can be found from appendix (a) . the weighting factors for i=0 is given as:    l i i aa 1 ,0, 1  … (19) three gray-gases model it has seen in equation (12), that the mean free path is a function of the absorption coefficients, which has a variable value from zone to zone, according to that zone's temperature. in the present work three gray-gases model will be used to represent the non gray-gas included in the system, which simulation the radiation zone of al-mussaib power plant by using monte carlo method 70 ijcpe vol.16 no.4 (dec. 2015) -available online at: www.iasj.net means that the gas is consisting of three gray gases, and clear part. for each gray gas, a different value of aborption coefficient will be used, then four values of total exchange area will be kept in the calculations, hence, the values of total exchange area will be expressed as:     n n niiinii xytaxy 0 )( … (20) where, an is the weighting factor at the gray gas i, which is obtained in (16). results and discussions it is important now to apply the radiation heat transfer to evaluate the temperature of each gas zone. to do this, the energy balance equations for each gas zone should be solved, which contains terms of convection, advection, and combustion rate, as well as the terms of radiative transfer terms. after solving the energy balance equations, the temperature distribution is determined. figures (2), and (3) show the temperature distribution at (70%) load of the furnace for the first layer beside the front wall (k=l), and the core layer (k=2), respectively. the figures show that, in general, the second row (i=2) have a general values of temperature less than the first row, this is because that the first row (i=1) is a combustion region, where as the second row is not. the temperatures increase in the third row due to heat liberation by combustion, which will has temperature values higher than, such of zones. the temperature values will decrease when the flue gases going up until reaching its lower value in the furnace just before leaving the furnace. the reason behind the temperature values decreasing when the flue gases going up, is due to the loosing of heat both by radiation and convection to the walls of the furnace. because of the strong effect of the advection from bottom rows to the upper rows, it can be seen that for each row the middle zone temperature is lower than other zones in the same row, where the zones at the sides are the higher temperature zones. it is also can be seen that the right side of the furnace is slightly higher than the left side, due to the effect of the neck part, which represent the top four gas zones on the left sides, where the flue gases are leaving the furnace. this part of the furnace is colder than other parts, which means it absorbs heat by radiation from the left side of the furnace, more than the right side due to the neighboorhood of that zones to this side. one can also notice that, the temperature values of the core layer (k=2), are higher than the values of the first layer (k=l), this is because of the effect of the front wall, which absorb heat by convection, where the core layer has no convection heat transfer to wall, only on the sides. to check the validity of the previous results, first, the outlet temperature of the flue gases will be checked with the test values of the designing company. the comparisons show that, the outlet temperature of the flue gases at (70%) load is (1090c 0 ), where the rate of the temperature leaving the furnace shown in figures (2) and (3), is (1092c 0 ), then there is a percentage of error of (0.18%), which is a good percentage, and the calculation is said to be good. another comparison will be made is with al-habbubi [7], where the results are obtained by using the zonal method as shown in figures (4) and (5). in general the distribution, and the variation of the distribution, has agreement. the difference is at the local values of the layers, where in the tahseen ali al-hattab, ali abd al-muhsen al-assady and wisam ahmed abd al-wahid -available online at: www.iasj.net ijcpe vol.16 no.4 (dec. 2015) 71 first layer (k=1), the temperature values are higher than, the first layer (k=l), obtained by monte carlo method, where as for the opposite is evaluated at the core layer (k=2). the results show that monte carlo method has the higher temperatures than of the zonal method. the reason behind that is due to the assumption used, where at [7], half of the furnace is used in the calculations, but in the present work, the whole furnace is used, which make a difference in energy distribution of layers. this in general made the difference between the layers (k=l, and k=2) at monte carlo method layer and at the zonal method. then, the variation in the furnace sizing use made this difference of calculations. fig. 1, flow chart of monte carlo procedure simulation the radiation zone of al-mussaib power plant by using monte carlo method 72 ijcpe vol.16 no.4 (dec. 2015) -available online at: www.iasj.net fig. 2, temperature distribution for gas zones in (k) at layer beside the wall and for 70% load. tahseen ali al-hattab, ali abd al-muhsen al-assady and wisam ahmed abd al-wahid -available online at: www.iasj.net ijcpe vol.16 no.4 (dec. 2015) 73 fig. 3, temperature distribution for gas zones in (k) at core layer and for 70% load. simulation the radiation zone of al-mussaib power plant by using monte carlo method 74 ijcpe vol.16 no.4 (dec. 2015) -available online at: www.iasj.net fig. 4, temperature distribution (k) for 70% load. temperature in figure is for layer beside the wall volume zone from [7] tahseen ali al-hattab, ali abd al-muhsen al-assady and wisam ahmed abd al-wahid -available online at: www.iasj.net ijcpe vol.16 no.4 (dec. 2015) 75 fig. 5, temperature distribution (k) for 70% load. temperature in figure is for core layer volume zones from [7]. simulation the radiation zone of al-mussaib power plant by using monte carlo method 76 ijcpe vol.16 no.4 (dec. 2015) -available online at: www.iasj.net conclusions a three-dimensional monte carlo procedure is used to predict the temperature and the heat flux distributions inside the furnace of almussaib power plant with verious loads by using the available data at the field. from the previous discussions it can be concluded that: 1the results of normal working conditions give a good percentage of error when comparing this results with the testing data for the focused furnace, which means that monte carlo method gives a good results for radiation transfer analysis, and will give a good accurate results for temperature and heat flux distribution, only when applying a good assumptions for other physical processes occur in the furnace. 2the weighted sum of gray gases model gives a good results to represent the emissivity, and the absorbtivity coefficients of non-gray gas. 3the postulated flow pattern is a very important character, which effects mainly on the final data. 4complex geometries can be studied to evaluate it's total exchange areas for zones, by using monte carlo method without much difficulties. 5monte carlo method is suffering from very high computational time, but it still an attractive method. list of symbols symbol description units a weighted factor a area m 2 b coefficient of the emissivity polynomial c coefficient of the absorptivity polynomial cp specific heat coefficient j/kg.k d diameter m gg the total radiative interchange area between two volume zones m 2 gs the total radiative interchange area between any volume zones and any surface zones m 2 gx the total radiative interchange area between any volume zones and any zones. m 2 h convection heat transfer coefficient w/ m 2 .k i iteration index j iteration index k gas absorption coefficient m -1 l beam length m m· mass flow rate kg/m 2 n number of bundles q heat transfer w r random number sg the total exchange area between any surface zone and any volume zone m 2 ss the total exchange area between any two surface zones m 2 sx the total exchange area between any surface zone and any zone m 2 t temperature k v volume m 3 tahseen ali al-hattab, ali abd al-muhsen al-assady and wisam ahmed abd al-wahid -available online at: www.iasj.net ijcpe vol.16 no.4 (dec. 2015) 77 greek symbols symbol description units α absorbtivity γ azimuthal angle radius θ polar angle radius ε emissivity τ optical depth atm.m σ stephanboltzmann constant. (5.669x 10~ 8 ) w/m 2 k 4 subscript symbol description a surface b black d flux to wall f advection g gas h generation i general gas number j general zone number in inward out, g outward gas zone out, s outward surface zone r radiation s surface up upstream v volume α absorption γ angle ε emissivity references 1howell, j.r., and perlmutter, m., "monte carlo solution of thermal transfer through radiant media between gray walls", transactions of the asme j. of heat transfer, vol. 86, no.l, pp. 116-122, 1964. 2siegel, robert, and howell, john r., "thermal radiation heat transfer", 2 nd edition, mcgrawhill, 1981. 3vercammen, h.a.j., and froment, g.f., "improved zone method using monte carlo techniques for the simulation of radiation in industrial furnaces", int. j. heat mass transfer, vol. 23, pp. 329337, 1980. 4steward, f.r., and guruz, h.k., "mathematical simulation of an industrial boiler by the zone method of analysis", part 1 : heat transfer in steady confined flame, ch. 3, pp. 46-71, 1974. 5gupta, r.p., wall, t.f., and truelove, j.s., "radiative scatter by fly ash in puiverized-coal-fired furnaces: application of the monte carlo method to anisotropic scatter", int. j. heat mass transfer, vol. 26, no. 11, pp. 1649-1660, 1983. 6kudo, ki, taniguchi, hi, kuroda, a., and sasaki, t., "development of general purpose computer code for two/three-dimension heat transfer analysis", proceeding of the seventh int. conf. held in u.s.a., vol. vii, part 1, 1991. 7al-habbubi, mohanned mohammed, "radiative heat transfer in boilers using the zonal method", m.sc. thesis, university of babylon, 2002. appendix the values of the coefficient for emissivity of mixtures are given in table (a-1) and the values of the coefficient for the absorptivity of mixtures are given in table (a-2). simulation the radiation zone of al-mussaib power plant by using monte carlo method 78 ijcpe vol.16 no.4 (dec. 2015) -available online at: www.iasj.net table (a-1), coefficients for emissivity mixture, 1/  cw pp i i k 1 1,, 10  i b 4 2,, 10  i b 7 3,, 10  i b 11 4,, 10  i b 1 0.4303 5.150 -2.303 0.9779 -1.494 2 7.055 0.7749 3.399 -2.297 3.770 3 178.1 1.907 -1.824 0.5608 -0.5122 1 t p atm, 0.001≤ ps≤10.0 atm-m, 600≤ t ≤ 2400 k table (a-2), coefficients for absorptivity of mixtures kia c ,, 1/  cw pp k i j 1 2 3 4 1 1 0.55657 e-00 -0.62824 e-03 0.31876 e-06 -0.52922 e-10 2 1 0.16676 e-01 0.15769 e-03 -0.10937 e-06 0.19588 e-10 3 1 0.28689 e-01 0.20697 e-03 -0.17473 e-06 0.37238 e-10 1 2 0.32964 e-03 0.27744 e-06 -0.26105 e-09 0.37807 e-13 2 2 0.50910 e-03 -0.76773 e-06 0.40784 e-09 -0.69622 e-13 3 2 0.24221 e-03 -0.55686 e-06 0.34884 e-09 -0.67887 e-13 1 3 -0.53441 e-06 0.33753 e-09 -0.10348 e-12 0.26027 e-16 2 3 0.37620 e-07 0.18729 e-09 -0.15889 e-12 0.30781 e-16 3 3 -0.19492 e-06 0.36102 e-09 -0.21480 e-12 0.41305 e-16 1 4 0.12381 e-09 -0.90223 e-13 0.38675 e-16 -0.99306 e-20 2 4 -0.32510 e-10 -0.26171 e-13 0.29848 e-16 -0.58387 e-20 3 4 0.41721 e-10 -0.73000 e-13 0.43100 e-16 -0.83182 e-20 1 t p atm, 1.0 c p atm, 0.001≤ ( wc pp  ) s ≤ 10.0 atm-m, 600 ≤ t, s t ≤ 2400 k available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.20 no.2 (june 2019) 51 – 59 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: saifalden y. alssafar , email: saifpet@yahoo.com, name: faleh h. m. al-mahdawi, email: fhmetr@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. new study of mgo nps in drilling fluid to reduce stick-slip vibration in drilling system saifalden y. alssafar and faleh h. m. al-mahdawi petroleum engineering department, university of baghdad abstract stick-slip is kind of vibration which associated with drilling operation in around the bottom hole assembly (bha) due to the small clearance between drill string & the open hole and due to the eccentric rotating of string. this research presents results of specific experimental study that was run by using two types of drilling mud (fresh water bentonite & polymer), with/without nanoparticle size materials of mgo in various ratios and computes the rheological properties of mud for each concentration [yield point, plastic viscosity, av, ph, filter loss (30 min), filter cake, mud cake friction, friction factor]. these results then were used to find a clear effects of nanoparticle drilling mud rheology on stick slip strength by several perspectives through a special “torque and drag” software which simulate the torque amount expected on bha during drilling a vertical well in different conditions using real drilling string design that usually used in iraqi oil fields. thus to mitigate or to prevent stick–slip and cure the sequence events that could happen to both of drilling string and the well, i.e. bit/bha wear, pipe sticking, borehole instability and low rate of penetration. our study concluded that there are good reduction in the torque from (2031lb-ft) to (1823lb-ft) using polymer mud and torque reduction from (4000lb-ft) to (3450lb-ft) using fresh water bentonite, these results do not include any breaking in the satisfactory range of other mud rheology. keywords: stick – slip motion, drilling mud, nano particles, mgo and drill string vibration received on 13/01/2019, accepted on 25/02/2019, published on 30/06/1029 https://doi.org/10.31699/ijcpe.2019.2.7 1introduction it is a usual routine that problems occur while drilling a well, even if we reviewed the well plan carefully. for example, in areas in which similar drilling practices are used hole problems may have been reported were no such problems existed previously in offset wells because formations are nonhomogeneous. therefore, several wells near each other may have different geological conditions. ‎[1], ‎[2] the failures of a drill string have increased obviously in the last 10 to 15 years due to the use of directional drilling modeling and complex models with expensive downhole tools which make vibration monitoring and controlling is a key of drilling optimization, and have become a serious issue resulting in substantial cost effective. therefore, detection and control of drill string vibrations have become an area of considerable interest. ‎[3] three main types of vibration frequently occur (individually or together) during drilling formation, (torsional vibration, axial vibration and lateral vibration). over limited vibration can cause drill string failure, poor directional tendency, premature bit failure, stalling of the top drive or rotary table, hole enlargement, mwd tool failure, and bit /stabilizer / tool joint wear‎[4]. torsional vibrations are often classified as one of the most damaging models of vibration when downhole tools called stick-slip phenomenon ‎[5], ‎[6]. 2aim of this study in this study, anew work is acted to find out the relationship between the using of (nano – mgo) materials in drilling mud and stick slip vibration during drilling in different concentrations. to achieve real results the test has been ran in two major types of drilling mud; freshwater bentonite (fwb) mud and polymer mud, to cover the drilling muds for both of shallow and deep wells. 3methodology mgo is usually manufactured by calcination of magnesium carbonates. in contrast to expansive additives, the reactivity of mgo is influenced by the manufacturing process. in comparison with other materials mgo exhibit a considerably higher free enthalpy, thus a higher reactivity, even in the dead-burnt state (manufacture at a temperature above 1600°c), while mgo nanoparticles are prepared by microwave-assisted synthesis using magnesium acetate, where mgo nano-powders is synthesized using microwave plasma torch.‎[7] it is clearly noticed that nano fluids made by nano mgo show specific properties such as a high tendency for adsorption, where mgo increases the effect of attraction forces in comparison with repulsion forces which results in fine fixation ‎[8], ‎[9]. https://doi.org/10.31699/ijcpe.2019.2.7 s. y. alssafar and f. h. m. al-mahdawi / iraqi journal of chemical and petroleum engineering 20,2 (2019) 51 59 25 3.1. sonication system ultrasonic system consists of 3 major components: generator, converter and probe (horn). the generator transforms ac line power to electrical energy with high frequency by providing high voltage pulses of energy at a frequency of 20 khz that drives a piezoelectric by converter, the probe’s tip expands and contracts longitudinally, this will lead to cavitation in the liquid and violent collapse of microscopic bubbles during rapid vibration. the collapse of many of cavitation bubbles releases a huge energy in the cavitation field. this feature is a keypad, which allows the user to adjust the sonication parameters as per test requirements ‎[10]. 3.2. ultrasonic dispersion of nanoscale materials has become dependent on ultrasonic methods. even with chemical dispersing agents, were to provide access to these agents onto material surfaces, ultrasonic is required. in usual dispersion runs, sonication takes 12-36 hrs. in order to ensure a good dispersion in an appropriate solvent. 3.3. ultra-sonic device (elma) ultrasonic device made for multipurpose duties: remove chlorine from water, kill bacterial cells, remove and recover ammonia from industrial waste water move and recover ammonia from industrial wastewater ‎[10] as shown in fig. 1 below: fig. 1. elma ultrasonic device 3.4. mud lubricity tester in this study, generally use the lubricity meter to measure the cof or the coefficient of friction (baroid lubricity coefficient) between the test ring and block ‎[11]. the lubricity test represents (simulates) drill pipe rotation against downhole surfaces, using a constant load of 150 inch-pounds (600psi) is applied using a torque arm. the lubricity tester is regularly used to evaluate and predict the impact made by a drilling fluid additive on friction. the following coefficients are recognized as acceptable value: 1cof for water-based mud, a coefficient < 0.2 2cof for oil-based mud, a coefficient < 0.1 3cof for ester-based mud, a coefficient < 0.1 fig. 2. ofite ep and lubricity tester the ofite ep and lubricity tester is used to measure and evaluate the lubricating quality of drilling fluids, predict wear rates of mechanical parts in known fluid systems and provide data to assess the type and quantity of lubricating additives that may be required. the following calculations is required: correction factor= 34 𝑀𝑒𝑡𝑒𝑟 (32 𝑡𝑜 36) lubricity coefficient =𝑀𝑒𝑡𝑒𝑟 𝑅𝑒𝑎𝑑𝑖𝑛𝑔 ×𝐶𝑜𝑟𝑟𝑒𝑐𝑡𝑖𝑜𝑛 𝐹𝑎𝑐𝑡𝑜𝑟100 percent of torque reduction= 𝐴−𝐵𝐴×100 where: a= torque reading of untreated mud, b= torque reading of treated mud and from viscometer: plastic viscosity (pv), cp= θ600 – θ300 (1) yeild point (yp), ib/100ft2= θ300pv (2) apparent viscosity (av), cp= θ600/2 (3) s. y. alssafar and f. h. m. al-mahdawi / iraqi journal of chemical and petroleum engineering 20,2 (2019) 51 59 25 gel strength, 10 second, ib/100 ft2= the maximum dial deflection after 10 sec gel strength, 10 minute, ib/100 ft2= the maximum dial deflection after 10 min. 3.5. torque and drag software using the results of the lab test we took the friction factor and put it in a special torque and drag software made by a global company to simulate a drilling job and find out torque on the bit. a. torque and drag software assumption the drilling model was build using parameters of idc56 to drill vertical well, 12 1/4” hole section, wob=28 30 klb. (wob =12 klb. for fwb mud where this mud used in shallow depth), rpm= 40 and fixed friction factor of 0.25 ft-lb between drilling string and 13 3/8” casing. the drilling bit and bha designed as follow: table 1. bha design item description od id weight length cum. lengt # (in) (in) (lbpf) (m) (m) 1 pdc 8.000 3.500 138.52 0.44 0.44 2 near-bit stabilizer with fv 8.000 3.000 147.22 2.31 2.75 3 mwd directional + gamma 8.000 4.000 128.48 9.90 12.65 4 1 x 8" drill collar 8.000 2.750 150.70 9.14 21.79 5 integral blade stabilizer 8.000 3.000 147.22 2.16 23.95 6 pbl circulating sub 8.000 3.250 143.03 2.00 25.95 7 5 x 8" drill collar 8.000 2.750 150.70 45.70 71.65 8 8" sledgehammer jar 8.120 2.750 132.58 6.66 78.31 9 1 x 8" drill collar 8.000 2.750 150.70 9.14 87.45 10 x-over sub 8.000 2.875 149.18 0.78 88.23 11 2 x 6 3/4" drill collar 6.750 2.750 101.50 18.28 106.51 12 15 x 5" hwdp 5.000 3.000 49.30 140.70 247.21 13 5" dp 5.000 4.276 21.92 9.00 256.21 4experimental work this work aims to improve the rheological properties of drilling mud by reducing the friction of the mud with less filtration plus thin mud cake. drilling fluids have prepared with two major types of mud (fwb & polymer mud) using varies nano mgo ratio. all experiments tests conducted under laboratory conditions, and then the mud hot rolled by heating for four hours in about 250 degree fahrenheit and retested again. table 2. polymer mud materials composition unit blank mixing time drill water cc 280.4 sodium chloride gr 61.3 5 min potassium chloride gr 11.6 5 min caustic soda gr 1 5 min soda ash gr 1.5 5 min starch gr 12 15 min pac lv gr 1 15 min xanthan gr 0.5 15 min limestone (50-75 μ) gr 87.6 20 min table 3. fwb mud materials composition unit blank sample mixing time drill water cc 350 bentonite gr 22.5 20 in 4.1. sample preparation a. procedure of nano-mgo dispersion 1nano mgo powder was mixed in distilled water and subjected to ultrasonic bath. 2surfactant for efficient dispersion of nanoparticles was mixed in distilled water and subjected to ultrasonic bath too. 3 in the end, both solutions were merged and put in the ultrasonic bath for 7-8 hours. 4we made five samples (cups), the first cup without mgo (as a blank) then adding 0.3, 0.6, 0.9, 1.5 gm of mgo consequently. 5different concentrations of this nano-colloidal solution added to the drilling fluid system as following: i. 280.4 cc of polymer mud. ii. 350 cc of fwb. b. prepare polymer mud preparing was made based on the following table and mixed them by multimixer fann 9b: table 4. composition of polymer mud composition unit blank mixing time drill water cc 280.4 sodium chloride gr 61.3 5 min potassium chloride gr 11.6 5 min caustic soda gr 1 5 min soda ash gr 1.5 5 min starch gr 12 15 min pac lv gr 1 15 min xanthan gr 0.5 15 min limestone (50-75 μ) gr 87.6 20 min s. y. alssafar and f. h. m. al-mahdawi / iraqi journal of chemical and petroleum engineering 20,2 (2019) 51 59 25 1adding nano material (different concentration) to blank of polymer mud and mix for 20 min. 2measure viscosity by rotational viscometer model ofite 800 ( based on the attached procedure) at 120 ο f 3put prepared mud in hot roll for evaluating rheological properties in downhole situation at 250 ο f during 4 hrs. 4after hot roll, measure viscosity at 120 ο f by rotational viscometer model ofite 800 5measure filtrate volume by api filter press model fan 300series (based on mentioned procedure) at room temperature and 100 psi pressure work. 6evaluate lubricity factor by ep/ lubricity tester (based on mentioned procedure) c. preparing bentonite mud the preparing was made based on the following table then aged in hot roll: table 5. fwb mud materials composition unit blank sample mixing time drill water cc 350 bentonite gr 22.5 20 min 1aging prepared mud in room temperature for 18 hrs. 2adding nano material to prepared mud in the required concentration and mixing by a multi mixer at 20 min. 3measure viscosity at 120 ο f by rotational viscometer model ofite 800 (based on the mentioned procedure) 4measure filtrate volume by api filter press model fan 300series (based on the attached procedure) at room temperature and 100 psi pressure work. 5evaluate the lubricity factor by ep/ lubricity tester (based on attached procedure). d. preparing nano material preparing nano material for all experimental work can be concluded as follow: 1. add nano material to water and disperse it in water by ultrasonic for 1 hour. 2. add prepared nano solution to surfactant and disperse them for 7 hrs by ultrasonic ( this is final nano solution) 3. add final nano solution to polymer mud in during mixing based on required concentration for 20 minutes. 5results and discussion 5.1. polymer mud test with nano mgo additives mud rheology changes after adding nano mgo to 280.4 cc of polymer mud by various concentrations as shown in table 6 table 6. mud rheology parameters rheology -------gm 0.3 gm 0.6 gm 0.9 gm 1.5 gm av 21.5 24 24 35.5 36.5 rpm 600 43 48 48 71 73 rpm 300 26 30 28 43 46 pv 17 18 20 28 27 yp 9 12 8 15 19 rpm 200 19 22 21 31 33 rpm 100 12.5 13.5 13 19 20 rpm 6 3.5 3.5 3 5 5 rpm 3 2.5 3 2.5 5 4 gel 10 s 3 4 3 4 5 gel 10 min 4 5 4 5 6 ph 12.21 10.87 11.24 11.11 10.98 api fl, cc 2.2 2.7 2.3 3 2.8 settlement yes no no no no filter cake 1/32 1/32 1/32 1/32 1/32 foam no no no no no water torque reading 33.7 34.4 34.3 36.0 35.0 mud torque reading 20.1 20.0 19.9 19.6 21.2 lubricity factor 0.2028 0.19767 0.1973 0.1851 0.2059 torque reduction 0.5 0.9 2.4 mud cake friction (kf) 0.2046 0.2268 0.16578 0.18323 0.25303 s. y. alssafar and f. h. m. al-mahdawi / iraqi journal of chemical and petroleum engineering 20,2 (2019) 51 59 22 fig. 3. polymer mud with different mgo nps concentrations in fig. 3, both mud cake friction and lubricity factor multiplied by 10 to clarify the change for review because their amount is too small. the diagram of test 7 illustrated that the mgo concentration of 0.9 gm in polymer mud is the most affected with regards to torque reduction with the amount “0.1851” of cof. at the same time the test of 0.9 concentration has no significant changes in other mud rheology except pv which recorded (26) where its higher than the pv at blank and (0.3 gm) tests, as per nanomaterials are solid structure so higher pv is typical results. we can also notice yp 0.9 gm test is higher than the previous two tests but still in the allowable range to raise cutting with no formation damage. in table 7 friction mud rheology changes after adding nano mgo to 280.4 cc of polymer mud by various concentrations. table 7. cof, kf with torque reduction rheology ------- gm 0.3 gm 0.6 gm 0.9 gm 1.5 gm lubricity factor 0.2028 0.19767 0.1973 0.1851 0.2059 torque reduction 0.5 0.9 2.4 mud cake friction (kf) 0.2046 0.2268 0.16578 0.18323 0.25303 fig. 4. cof, kf and torque reduction with related to mgo nps additives in polymer fig. 5. cof & torque reduction & kf of five tests in polymer 0 5 10 15 20 25 30 35 40 av pv yp gel 10 sgel 10 min ph api fl, ccmud torque readinglubricity factortorque reductionmud cake friction (kf) nanomgo in polymer mud (cof & kf*10) -------gm 0.3 gm 0.6 gm 0.9 gm 1.5 gm s. y. alssafar and f. h. m. al-mahdawi / iraqi journal of chemical and petroleum engineering 20,2 (2019) 51 59 25 table 8. magnitude of cof with mgo concentration rheology ------- gm 0.3 gm 0.6 gm 0.9 gm 1.5 gm lubricity factor 0.2028 0.19767 0.1973 0.1851 0.2059 fig. 6. mgo consentration&cof in polymer in fig. 4, fig. 5 & fig. 6, it was clear that the 0.9 gm of nano mgo had got the best cof (lowest value) that led to decline in torque reading. however, the cof and lubricity factor had risen dramatically when the nano concentration increased more than 0.9 gm. in addition, there is improvement in cof between 0.6 to 0.9 gm but noticed stability in cof in between 0.3 to 0.6 gm. in another hand although there was cof decreasing when 0.3 gm added, but not as fall as the test of 0.9 gm mgo. in table 9 the recorded data of torque software regarding lubricity factor changes with tests table 9. cof and torque reading data rheology ------- gm 0.3 gm 0.6 gm 0.9 gm 1.5 gm lubricity factor 0.2028 0.19767 0.1973 0.1851 0.2059 torque reading 2031 1963 1950 1823 2050 fig. 7. polymer & mgo torque software reading from fig. 8 & fig. 9, general in the blank test the software reads 4000 ft-lb and start decreasing by adding nano mgo until getting its best amount in this lab tests, then refers back to 4000 in concentration nano mgo of 1.5 gm. so using nano mgo more than (1) gm per 280.4 cc of polymer mud should be avoided because of it sharply higher the friction factor and mud torque amount. fig. 8. polymer& mgo torque reading on software the best result recorded in the test was 0.9 gm mgo, however there was a little high av and pv (av =35.5 & pv =28). and that due to the loos of other nano benefits and maybe 0.9 gm or above cannot be used when plastic viscosity is restricted in certain drilling problems expected. therefore, the same restriction with regards to the limitation of pump pressure and/or ecd (equivalent circulating density) then lead to using low av (where, av= shear stress/shear rate),so it will require higher pressure. 5.2. fresh water bentonite mud test with nano mgo additives using five cup tests consist of fwb and nano mgo in different concentrations we got the results in table 10. table 10. mud rheology changes after adding nano mgo to 350 cc of fwb mud by various concentrations rheology@ 120 f blank 0.3 gm 0.6 gm 0.9 gm 1.5 gm av 19 20 21 33.5 42 rpm 600 38 40 42 67 84 rpm 300 35 35 39 62 79 pv 3 5 3 5 5 yp 32 30 36 57 74 rpm 200 33 37 38 62 76 rpm 100 30 35 37 59 72 rpm 6 25 33 34 56 66 rpm 3 24 33 33 55 65 gel 10 s 24 35 35 46 61 gel 10 min 25 37 38 52 66 ph 9.18 11.40 11.23 11.26 11.25 api fl, cc 14 14.3 16.4 17.0 15.2 settlement no no no no no filter cake 4/32” 4/32” 5/32” 5/32” 4/32” foam no no no no no water torque reading 35.5 34.5 34.8 35.9 33.9 mud torque reading 44.3 36.3 33.4 39.9 37.0 lubricity factor 0.4243 0.3577 0.3266 0.3779 0.3711 torque reduction 18.05 24.06 9.93 16.48 mud cake friction (kf) 0. 69 0.0959 0.1483 0.1919 0.1745 s. y. alssafar and f. h. m. al-mahdawi / iraqi journal of chemical and petroleum engineering 20,2 (2019) 51 59 25 fig. 9. nano mgo in fwb (lubricity factor & mudcake friction*10) in fig. 9 both mud cake friction and lubricity factor multiplied by 10 to make it clear for review because their amount are too small. fig. 10. lubricity factor (nano mgo in fwb) table 11. cof & torque and drag software reading rheology ------- gm 0.3 gm 0.6 gm 0.9 gm 1.5 gm lubricity factor 0.4243 0.3577 0.3266 0.3779 0.3711 torque reading 4000 3500 3450 3580 3560 fig. 11. sofy ware torque reading in fwb with mgo by fig. 11 we can find that nano mgo additives reduced the expected downhole torque by more than 1500 ft-lb in the concentration of 0.6 gm. and noticed a clear curve retrograded since the first nano mgo was added to explain the perfect acting of that nanoparticles to fwb, then to records its best torque reduction at concentration of 0.6 gm. in mgo concentration between 0.6 – 0.9 torque goes high but still lower than it amount before adding mgo, because of the nanoparticles of mgo has good effects on that mud lubricity . in the concentration of 1.5 gm there is a little drop in torque which may indicate that will continue drop with adding mgo proportionally, however it will be cost effect and will raise other mud rheology i.e. gel and pv. 6conclusion & recommendations the following are concludes the experimental results overall: 1in polymer mud lubricity factor dropped from 0.2 to be 0.185 when we increased nano mgo from zero to 0.9 gm gradually by the tests then cof starts increasing again with more nano mgo. 2even though it was a minimal decrease in cof with nano additives, but it succeeds to change torque reading from 2031lb-ft… to 1823lb-ft…. which lead to avoid 12.5% of stick-slip vibration probability. 3no changes were noticed in the other mud rheology except increasing in plastic viscosity due to nano particles, so we highly recommend using nano mgo as additives in drilling companies working in iraq, especially in forecast projects no more vertical wells as much as deviated and horizontal wells which stick and slip as commonly occurs. 4nano mgo performs better rheology results with fwb mud where cof dropped (0.42 0.32), with a clear drop in torque reading (4000 3450). 5the other rheology parameters were normal and acceptable to be used, therefore we recommend using nano mgo in drilling fluid to mitigate stick-slip phenomenon, in nano ratio of 1.73 kg per one cubic meter of mud. finally some of the important recommendations supposed to be in mined by future researchers: 1re-run the experimental work using different mgo nano concentrations of the same nanomaterials to detect any sensitive in mud rheology. 2 choose another type of drilling muds like oil-based mud, salt mud, emulsion mud and kcl mud that used in oil fields to explore the nano-particles effects. 3making a special device (similar to a drilling rig in small scale) consist of a small bit, bha and source of wob with rotating advanced by torque sensors, to simulate drilling a hole and evaluate the real stick – slip vibration changes with regards to adding different nanoparticles types & weight ratio. s. y. alssafar and f. h. m. al-mahdawi / iraqi journal of chemical and petroleum engineering 20,2 (2019) 51 59 25 acknowledgment our sincere appreciation goes to dr. faleh m. h. almahdawi whose contribution and constructive criticism has pushed me to expend the kind of efforts to make this work as original as it can be. our grateful to all of those with whom we have had the pleasure to work during this and other related projects. nomenclatures & abbreviations av apparent viscosity cof coefficient of friction ff friction factor hrs. hours idc iraqi drilling company (rig number) bha bottom hole assembly np nano particle nps nano particles pv plastic viscosity, cp rop rate of penetration fw fresh water bentonite yp yield point, ib/100ft2 cp cent poise γ shear rate, sec-1 τ shear stress, ib/100ft2 μp plastic viscosity, cp τ0 shear stress at yield point, ib/100ft2 𝜏1 shear stress at lower shear rate 𝜏2 shear stress at higher shear rate references [1] å. kyllingstad and g. w. halsey, “a study of slip/stick motion of the bit,” spe drill. eng., vol. 3, no. 4, pp. 369–373, 1988. [2] m. i. abdulwahab, s. thahab, and a. h. dhiaa, “experimental study of thermophysical properties of tio2 nanofluid”, ijcpe, vol. 17, no. 2, pp. 1-6, jun. 2016. [3] y. q. lin and y. h. wang, “new mechanism in drillstring vibration,” offshore technol. conf., 1990. [4] b. a. abdulmajeed and n. s. majeed, “study and analysis of concentric shell and double tube heat exchanger using tio 2 nanofluid,” iraqi j. chem. pet. eng., vol. 18, no. 4, pp. 15–23, 2017. [5] t. v aarrestad and h. blikra, “torque and drag: key factors in extended-reach drilling,” iadc/spe drill. conf., no. spe 27491, pp. 547–552, 1994. [6] n. majeed and d. naji, “synthesis and characterization of iron oxide nanoparticles by open vessel ageing process”, ijcpe, vol. 19, no. 2, pp. 2731, jun. 2018. [7] f. h. m. al-mahdawi and k. saad, “enhancement of drilling fluid properties using nanoparticles”, ijcpe, vol. 19, no. 2, pp. 21-26, jun. 2018. [8] b.-q. xu, j.-m. wei, h.-y. wang, k.-q. sun, and q.m. zhu, “nano-mgo: novel preparation and application as support of ni catalyst for co2 reforming of methane,” catal. today, vol. 68, no. 1–3, pp. 217–225, 2001. [9] n. jafariesfad, y. gong, m. r. geiker, and p. skalle, “nano-sized mgo with engineered expansive property for oil well cement systems,” spe bergen one day semin., 2016. [10] g. t. caneba, c. dutta, v. agrawal, and m. rao, “novel ultrasonic dispersion of carbon nanotubes,” j. miner. mater. charact. eng., vol. 09, no. 03, pp. 165–181, 2010. [11] k. slater and a. amer, “new automated lubricity tester evaluates fluid additives, systems and their application,” pp. 1–8, 2013. 1-%09https:/www.researchgate.net/publication/245548947_a_study_of_slipstick_motion_of_the_bit 1-%09https:/www.researchgate.net/publication/245548947_a_study_of_slipstick_motion_of_the_bit 1-%09https:/www.researchgate.net/publication/245548947_a_study_of_slipstick_motion_of_the_bit http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/76 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/76 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/76 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/76 https://www.onepetro.org/conference-paper/otc-6225-ms https://www.onepetro.org/conference-paper/otc-6225-ms http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/68 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/68 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/68 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/68 https://www.researchgate.net/publication/250088572_torque_and_drag-two_factors_in_extended-reach_drilling https://www.researchgate.net/publication/250088572_torque_and_drag-two_factors_in_extended-reach_drilling https://www.researchgate.net/publication/250088572_torque_and_drag-two_factors_in_extended-reach_drilling http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/163 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/163 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/163 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/163 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/162 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/162 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/162 8-%09https:/www.sciencedirect.com/science/article/pii/s0920586101003030 8-%09https:/www.sciencedirect.com/science/article/pii/s0920586101003030 8-%09https:/www.sciencedirect.com/science/article/pii/s0920586101003030 8-%09https:/www.sciencedirect.com/science/article/pii/s0920586101003030 8-%09https:/www.sciencedirect.com/science/article/pii/s0920586101003030 https://www.onepetro.org/conference-paper/spe-180038-ms https://www.onepetro.org/conference-paper/spe-180038-ms https://www.onepetro.org/conference-paper/spe-180038-ms https://www.onepetro.org/conference-paper/spe-180038-ms https://www.researchgate.net/publication/229043259_novel_ultrasonic_dispersion_of_carbon_nanotubes https://www.researchgate.net/publication/229043259_novel_ultrasonic_dispersion_of_carbon_nanotubes https://www.researchgate.net/publication/229043259_novel_ultrasonic_dispersion_of_carbon_nanotubes https://www.researchgate.net/publication/229043259_novel_ultrasonic_dispersion_of_carbon_nanotubes https://www.onepetro.org/conference-paper/omc-2013-169 https://www.onepetro.org/conference-paper/omc-2013-169 https://www.onepetro.org/conference-paper/omc-2013-169 s. y. alssafar and f. h. m. al-mahdawi / iraqi journal of chemical and petroleum engineering 20,2 (2019) 51 59 25 الى طين الحفر لتقليل ظاهرة االلتصاق mgoدراسة حديثة عن تأثيراضافة مادة النانو ( خالل عملية حفر االبار.stick-slipواالنزالق) الخالصة مجموعة رأس البئر ظاهرة االلتصاؽ واالنزالؽ هي احد انواع االهتزازات التي تحدث اثناء عمميات الحفر حوؿ نتيجة لصغر الفراغ الحمقي بيف التجويؼ المفتوح ومجموعة رأس البئر وكذلؾ بسبب الدوراف الالمركزي لخيط الحفر اثناء الحفر. في هذا البحث استعراض لنتائج مختبرية باستخداـ نوعيف رئيسييف مف طيف الحفر وذلؾ باضافة النانو mgo ى تأثيرها عمى خواص طيف الحفر بشكؿ عاـ ولتحديد قيـ معمؿ االحتكاؾ بتراكيز مختمفة لمعرفة مد بشكؿ خاص, ثـ ادخاؿ قيـ معامؿ االحتكاؾ المستحصمة مف التجارب في برنامج خاص )سوفتوير( لتحديد قيـ المتوقعة حوؿ مجموعة قعر البئرمف خالؿ عمؿ ممارسة فعمية في البرنامج stick-slipاالحتكاكات مف نوع ر بئر عمودي باالستفادة مف بعض التصاميـ الفعمية لخيط الحفر والمستخدمة في الحفر االبار الحد الحقوؿ لحف العراقية. اف الهدؼ مف هذا العمؿ هو لمحصوؿ عمى نماذج طيف حفر تقمؿ او تمنع حدوث ظاهرة االلتصاؽ واالنزالؽ التي يؤدي حدوثها الى مشاكؿ حفر عديدة كػ : تمؼ الحافرة وممحفاتها, التصاؽ االنابيب, عدـ استقرار جدار البئر, انخفاض معدؿ االختراؽ. ( كاالتي:torqueحققت انخفاض في جهد االحنكاؾ ) mgoمف النانو نجحت دراستنا في ايجاد تراكيز .polymerفي طيف الحفر نوع 2210 – 1302 .fresh water bentoniteفي طيف حفر نوع 0043 – 0333 عمما اف النتائج اعاله كانت متزامنة مع مواصفات طيف الحفر ضمف المدى المقبوؿ لتحقيؽ اهداؼ سائؿ قطع الصخرية المحفورة وتعميقها عند التوقؼ وغيرها مف مهاـ طيف الحفر.الحفر كػرفع ال available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.20 no.1 (march 2019) 65 – 68 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: majid m. majeed, email: majid.majeed@hotmail.com, ayad a. alhaleem, email: ayadah62@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. selection of suitable drilling parameters for obtaining high rate of penetration in majnoon oilfield majid m. majeed and ayad a. alhaleem petroleum engineering department/ college of engineering/ university of baghdad abstract several directional wells have been drilled in majnoon oilfield at wide variation in drilling time due to different drilling parameters applied for each well. this technical paper shows the importance of proper selection of the bit, mud type, applied weight on bit (wob), revolution per minute (rpm), and flow rate based on the previous wells drilled. utilizing the data during drilling each section for directional wells that's significantly could improve drilling efficiency presented at a high rate of penetration (rop). based on the extensive study of three directional wells of 35 degree inclination (mj-51, mj-52, and mj-54) found that the applied drilling parameters for mj-54 and the bit type within associated drilling parameters to drill 36", 24", 16" and 12 1/4" hole sections is the best, although the drilling parameters in 8 1/2" hole section for mj-51 and selected bit type are the best for future wells. keywords: drilling parameters, bit type, majnoon oilfield, and hole section received on 09/09/8102, accepted on 04/11/8102, published on 01/03/8109 https://doi.org/10.31699/ijcpe.2019.1.9 1introduction majnoon oil field was discovered in 1975 by braspetro oil company. the field was named majnoon which means 'crazy' in arabic in reference to the dense accumulation of oil in the area. the field located 60 km from basra city in southern ‎[1] fig. 1. fig. 1. majnoon field location map ‎[1] it is generally known that time is money and improving the rop will reduce the cost of the well, the major factors that affect the drilling time and costs are bit type, mud type, wob, rpm and flow rate, therefore the primary criteria of drilling optimization is an economical approach resulted in optimization based on the correct selection of wob, rpm, and bit types which produce the highest rop and consequently the minimum cost of drilling ‎[2]. in majnoon oil field, the drilling time required to reach section total depth (td) varied from one well to another, therefore a thorough analysis conducted to identify the shortest time per each section. 2well design the wells in majnoon oil field were drilled either to mishrif carbonates, nahr-umer sands, or zubair sands. first, the top hole section is drilled across upper fars formation with 36" bit to an approximately 100m depth where the weak formations existed, and 30" conductor casing is cemented in place to ensure that the water table had been adequately cased-off . second, the surface hole section is drilled to seal off the unconsolidated formations which are typically consists of clay and sands with 24" bit to 600 m depth. the 18 5/8" surface casing is set vertically and cemented to surface and the kick-off point designed in the next hole section at sufficient distance below the previous casing shoe depth ‎[3]. https://doi.org/10.31699/ijcpe.2019.1.9 m. m. majeed and a. a. alhaleem/ iraqi journal of chemical and petroleum engineering 20,1 (2019) 65 68 66 third, the intermediate section is drilled with 16" bit to 1500 m across lower and ghar formations. the 13 3/8" casing is run and cemented, 150m inside the previous casing. next is the second intermediate 12 1/4" section is drilled to 2500m through dammam, uer, aliji, shiranish, hartha, saadi, tanuma, and khassib formations. the 9 5/8" casing is run and cemented, 100m inside the previous casing section. finally, the 8 1/2" production section is drilled to reach well total depth (td) and desired reservoir zone; the 7" casing liner run and cemented 150 m inside the previous casing ‎[3]. fig. 2. stratigraphic column of majnoon oil field [1] m. m. majeed and a. a. alhaleem/ iraqi journal of chemical and petroleum engineering 20,1 (2019) 65 68 66 3analysis and discussion the previously drilled wells (mj-51, mj-52, and mj54) were researched thoroughly and from the findings discovered the optimized drilling parameters in majnoon oilfield. optimization process characterized by the concentrating on the wob, rpm, flow rate, bit type, and mud type, where the rop rely heavily on these variables. based on the data collected from (mj-51, mj-52, and mj-54) wells that were drilled in majnoon oilfield, the shallow formations were described in two hole sections 36" and 24" sections. the major issue encountered during drilling is the bit balling criteria due to clay hydration, therefore it is significant to know that in mj-54 were drilling parameters largely different compared with mj-51 and mj-52, mud salinity was 65,000 ppm rather than 45,000 ppm in previous wells, however bit type used in studied wells is the tri-cone bit ,‎[4] table 1. table 1. 36" and 24" hole section drilling parameters [5] well name bit type wob (klbs) rpm flow rate (gpm) rop (m/hr) mj-51 xt1grc 25-30 60-90 350-500 10 mj-52 xt1grc 20 60-80 350-550 8 mj-54 xt1grc 15-20 90-100 550-950 14.5 in well mj-54, the 36" and 24" hole sections shows the highest flow rate and rpm at 90-100 with minimal wob 15-20 kilo pounds (klbs) is beneficial to drill at higher rop of 14.5 m/hr, this is clear indications that the bit cleaned efficiently from the clay with 550-950 gallon per minute (gpm). these combinations of drilling parameters are likely to use for future wells ‎[5]. second, the 16" hole section in three wells was a buildup section and 35 degrees of inclination is the maximum inclination, table 2. table 2. 16" hole section drilling parameters ‎[5] well name bit type wob (klbs) rpm flow rate (gpm) rop (m/hr) mj-51 xt02sc 25-40 120 800 8 mj-52 sfd75dh 20-35 150 900-950 12 mj-54 sf76h 20-35 150 900-950 18 it is important to note that every well drilled a new bit used with slight changes to the applied drilling parameters; the average rop of 18 m/hr was achieved with pdc bit type (sf76h), this is the highest rop compared to the offset wells, due to the successful bit selection drilled the entire interval. ‎[6] table 3. table 3. 12 1/4" hole section drilling parameters ‎[3] well name bit type wob (klbs) rpm flow rate (gpm) rop (m/hr) mj-51 mme65dm 15-25 140 650-700 10 mj-52 mmd75h 15-20 150 600-700 12 mj-54 mmd75h 25-35 150 750-800 15 the bits for mj-52 and mj-54 is the same type but rop in mj-54 is 25% higher than the rop in mj-52 this is due to more wob implemented during drilling operation with 800 gpm flow rate ‎[6]. it is important to note that in 8 1/2" hole section drilling parameters wob and rpm that described in table 4 are not largely different from one well to another, however the bit type (mme74h) in well mj-51 showed impressive performance with 24m/hr rop, although the exceptional flow rate worked successfully to drill at 24m/hr ‎[6]. table 4. 8 1/2" hole section drilling parameters ‎[5] well name bit type wob (klbs) rpm flow rate (gpm) rop (m/hr) mj-51 mme74h 20-25 120-150 500-620 24 mj-52 mme75r 15-20 100-150 500-550 13 mj-54 mme75r 15-20 100-140 500 12 4conclusions 1it's important to know that during drilling (36" and 24") hole sections in mj-54 with higher flow rate and rpm compared with the previous wells, there was no bit balling encountered while drilling clay interval, achieved consistent rop of 14.5 m/hr. 2in well mj-54, while drilling 16" hole section an improved drilling performance was observed with the new bit design (sf76h). 3in well mj-54, while drilling 12 1/4" hole section, it's clearly indicates that an increase in wob had significant effect on the rop, wob varies directly with rop at the acceptable flow rate required to clean the bit. 4in well mj-51, while drilling 8 1/2" hole section, proper bit selection worked together with associated drilling parameters resulted in great drilling performance, a huge improvement compared to the offset wells. nomenclatures gpm: gallon per minute pdc: polly crystalline diamond compact ppm: parts per million rop: rate of penetration rpm: round per minute td: total depth wob: weight on bit m. m. majeed and a. a. alhaleem/ iraqi journal of chemical and petroleum engineering 20,1 (2019) 65 68 66 references [1] miguel armenta, rob tinkhof, "improving drilling performance at majnoon oilfield", uae: spe/iadc drilling conference and exhibition, 2013. [2] m.f. al dushaishi and r. nygaard, "selecting of optimum drilling parameters by incorporating drilling efficiency models", texas: iadc/spe drilling conference and exhibition, 2016. [3] marcle vesconte ," the majnoon field – a case study of drilling operations in remote area of iraq" texas: spe/ iadc drilling conference and exhibition, 2014. [4] south oil company" final well reports", iraq: 2014. [5] south oil company" mud logging data", iraq: 2014. [6] south oil company" bit records", iraq: 2014. اختيار معامالت الحفر المناسبه لزيادة معدل االختراق في حقل مجنون النفطي الخالصه معامالت حفر مختمفو لكل بئر لذلك تم حفر العديد من االبار المائمو في حقل مجنون النفطي باستخدام الوقت الالزم الكمال الحفر يختمف من بئر الى اخر. ىذه الدراسو تبين اىميو اختيار نوع الحافره ومعامالت الحفر االخرى المتمثمو بالوزن المسمط عمى الحافره مسبقو في حقل مجنون والسرعو دوران عمود الحفرومعدل الجريان اعتمادا عمى معمومات االبار المحفوره النفطي. اعتماد البيانات الحقميو لالبار المحفورة مسبقا تشكل مصدرا اساسيا لتحسين معدل اختراق الحافره, لذلك تم ( حيث تم استنتاج انو 35,مجنون35,مجنون 35)مجنون 53اجراء دراسو مكثفو لثالثو ابار مائمو وبدرجو (انج بينما 51,55,51,55.53( االنسب لحفر مقاطع )35المستخدمو في )مجنون معامالت الحفرونوع الحافره ( ىي االنسب لحفر االبار مستقبال".35( في )مجنون 5.3معامالت الحفر المستخدمو لحفر مقطع ) https://www.onepetro.org/conference-paper/spe-166685-ms https://www.onepetro.org/conference-paper/spe-166685-ms https://www.onepetro.org/conference-paper/spe-166685-ms https://www.onepetro.org/conference-paper/spe-178834-ms https://www.onepetro.org/conference-paper/spe-178834-ms https://www.onepetro.org/conference-paper/spe-178834-ms https://www.onepetro.org/conference-paper/spe-178834-ms https://www.onepetro.org/conference-paper/spe-167949-ms https://www.onepetro.org/conference-paper/spe-167949-ms https://www.onepetro.org/conference-paper/spe-167949-ms https://www.onepetro.org/conference-paper/spe-167949-ms iraqi journal of chemical and petroleum engineering vol.18 no.2 (june 2017) 57 67 issn: 1997-4884 study the performance of nanozeolite naa on co2 gas uptake najwa saber majeed and jwan taher majeed chemical engineering department, college of engineering, university of baghdad email: dr.najwa_saber@yahoo.com and eng.jwan1@yahoo.com abstract the adsorption isotherms and kinetic uptakes of co2 were measured. adsorption isotherms were measured at two temperatures 309 k and 333 k and over a pressure range of 1 to 7 bar. experimental data of co2 adsorption isotherms were modeled using langmuir, freundlich and temkin. based on coefficient of correlation it was found that langmuir isotherm model was well suited with the experimental data of co2 adsorption isotherms. in addition, adsorption kinetic of co2 mixture with n2 containing 10 % by volume co2 and 90 % by volume n2 were determined in a temperature 36 c and under the atmospheric pressure .when the flow rate was increased from 0.5 l/min to 2 l/min the time required for complete column saturation decreased. also the effect of bed length on breakthrough curves was studied. the adsorption capacity increases by bed length increasing for adsorption of carbon dioxide. key words: carbon dioxide, nanozeolite, adsorption. introduction global warming outcome from the emission of greenhouse gases has received common attention [1]. although there is little agreement on the causes of global warming and environmental problems, many scientists believe that the emission of greenhouse gases contributes to the majority of environmental problems. co2 is the most significant among all the anthropogenic greenhouse gases (ghgs). approximately 60% of global warming effects are attributed to carbon dioxide emission [2]. the term “greenhouse effect” was first coined by french physicist joseph fourier. the greenhouse effect is the absorption of infrared radiation by the atmospheric gases resulting in the trapping of heat, which results in heating of earth’s surface. greenhouse gases contribute significantly to climate change. according to the intergovernmental panel on climate change (ipcc), the increase in the global temperature is a result of increased concentrations of greenhouse gases caused by human activity such as fossil fuel burning, industrialization and deforestation [3]. in the past, the total amount of co2 was relatively maintained remained constant and the atmospheric source was considered large enough to accommodate any additional carbon dioxide until the industrial revolution university of baghdad college of engineering iraqi journal of chemical and petroleum engineering mailto:dr.najwa_saber@yahoo.com mailto:eng.jwan1@yahoo.com study the performance of nanozeolite naa on co2 gas uptake 58 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net [2]. the co2 concentration in atmosphere now is closed to 400 ppm which is significantly greater than the pre-industrial level of about 300 ppm [1]. according to the intergovernmental panel on climate change, the atmosphere may include up to 570 ppm of co2 in the year 2100 causing a rise of approximately 1.9 °c in the mean global temperature, and a raise of 3.8 m in the mean sea level [2]. currently fossil fuels supply more than 98% of the world's energy needs. however, the combustion of fossil fuels is one of the major sources of the green house gas co2 account roughly 40% of total co2 emission [4], [5]. growing concerns for global warming and climate change in recent years have motivated research activities toward improved and developing more efficient processes for carbon dioxide capture from large point sources, such as coal-fired power plants, natural gas processing plants, and cement plants. the development of efficient technologies for the capture of carbon dioxide produced by existing point sources will prove vital in controlling the environmental impact of anthropogenic emissions. in order for these technologies to be economically viable, capture carbon dioxide system must include adsorbent regeneration and operate effectively in realistic conditions [6]. there are several technologies available for co2 capture such as absorption, adsorption, gas separation, membrane, cryogenic separation, etc [4]. adsorption appears to be a more promising technology due to its easy operation and low energy requirements [7]. many conventional adsorbents are used for co2 adsorption such as bentonite, activated carbons and modified mesoporous silica [8]. zeolites represent one of the most innovative adsorbents for a wide range of applications including air separation, air drying, co removal from reforming gas, andco2 removal from natural gas [9]. zeolites are porous crystalline aluminosilicates with high surface areas and molecular sieving properties. the development of an effective carbon dioxide capture system is critical in reducing global greenhouse gas emissions. zeolites are considered particularly promising as co2 capture materials because their high surface areas and adjustable pore functionality enables the selective adsorption of large quantities of co 2. the primary cost in any co2 capture process is to obtain the energy required to regenerate the co2 loaded adsorbent after it has become saturated with co2. in zeolites, the strength of the interaction of co2 with the pore surface can be tuned to minimize the energy required for capture of a given amount of co2. the decrease in the particle size of zeolite crystals from the micro-level to the nano-level leads to a significant increase in specific surface area, thus providing more active sites for adsorption of co2 [8]. low-cost nanosized zeolite adsorbents that can combine a high adsorption capacity and good selectivity with rapid adsorption kinetics are of importance for carbon dioxide capture from flue gas. while the capacity and selectivity are primarily determined by the chemical and topological features of the pores, the uptake kinetics can also be controlled by reducing the diffusion length, e.g., by decreasing the particle size [10]. the main objectives that study the adsorption of carbon dioxide by using prepared naa_nanozeolite. experimental work 1. adsorbate in the present study two gases carbon dioxide and nitrogen were used as http://www.iasj.net/ najwa saber majeed and jwan taher majeed -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 59 adsorbate with purity a higher than 97.5%. 2. adsorbents prepared naa nano-zeolite was used as adsorbent. naa zeolite was synthesized according to sol-gel method by preparing two solutions seeding gel and the feedstock gel (rahman, 2012). the seeding gel prepared by adding 20 g deionized water, 4.1 g sodium hydroxide, 2.1 g sodium aluminate and 20 g sodium silicate and age at room temperature for 24 hr. the feedstock gel prepared by adding 131 g deionized water, 0.14 g sodium hydroxide, 13 g sodium aluminate and 140.5 g sodium silicate and then stirring vigorously until the gel appears smooth and then the overall gel was prepared by mixing the feed stock gel with 16.5 g of the seed gel for 40 min at room temperature. after that the final gel was stored in a water bath at 87 °c for 24 hr. the product obtained was filtered and repeatedly washed with deionized water until ph reached to 9 and then dried in an electrical oven for 24 hr at 100 °c and calcined 500 °c for 3 hr. figure 1 shows xrd pattern of prepared naa nano_zeolite. table 1 shows the characterization of nano-zeolite naa. fig. 1: xrd pattern of prepared naa nano_zeolite table 1: naa nano_zeolite characterization property value surface area, m 2 /g 581.211 pore volume, cm 3 /g 0.355 average particles diameter, nm 74.77 molar ratio of si/al 1.03 porosity, % 86.9594 3. adsorption equilibrium isotherm apparatus and method a photographic picture of the apparatus is shown in figure 2. all tubing was (3/8 in) copper were connected by fittings. the adsorption chamber and reservoirs were approximately 20 cm 3 iron sample cylinders. the pressure of gas was measured by a gauge (helicoid gauge) that ranged from (0-200 psig) with accuracy 1% and sensibility 0.02% of the full scale at all points. both reservoir and adsorption chamber were put in a water bath to provide constant temperature. all equipment was evacuated by vacuum pump in each experiment. the feed gas supplied from a cylinder that was connect with regulator pressure. http://www.iasj.net/ study the performance of nanozeolite naa on co2 gas uptake 60 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net the extrudate adsorbent was packed into the adsorption vessel and evacuated for 1hr under vacuum pump to regenerate the adsorbent (nanozeolite). this pre-treatment was allowed to make the measurements adsorption without change the adsorbents. after the adsorbent was pre-treated, the vacuum pump was powered off. the water bath with electrical hot plate was started up until constant temperature was reached. carbon dioxide gas was entered into the reservoir chamber through valve v1 until the required concentration was reached. v1 was then closed and the concentration recorded when it reached a steady value. after that the valve2 was opened and this system allows reaching equilibrium. the amount of gas adsorbed at equilibrium was determined from a mass balance. the amount of a component in the reservoir vessel before adsorption is equal to the amount remaining in this vessel after adsorption plus the amount in the gas phase in the adsorber vessel plus the amount adsorbed in the adsorber vessel. this balance can be written as follows: crivr=crfvr+crfva+wq rearranging q= ( )  in which q is the adsorbent loading at equilibrium (mmol/g), c is a concentration (mmol/l), v is a volume (l), εo is over all bed void fraction, and w is the weight of the adsorbent in adsorber vessel (g). the subscripts r, a, i and f refer to reservoir vessel, adsorber vessel, initial and final condition, respectively. fig. 2: photographic picture of apparatus used for adsorption equilibrium measurement http://www.iasj.net/ najwa saber majeed and jwan taher majeed -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 61 4. adsorption kinetics (breakthrough curves) apparatus and method a photographic picture of the apparatus is shown in figure 3. all tubing was copper (3/8 in), connected with fitting. the column of the adsorption was an iron pipe 65 cm long and 3.5 cm i.d. the gauze plate of mesh is sited at both ends of the column to hold packing in position from column ends. a pressure gauge was connected at the top of the column to provide the pressure of the process. the flow rate of inlet gas was controlled by a valve and measured by a rotameter and the outlet gas measured by gas analyzer. the extrudate adsorbent was packed into the vessel adsorption and evacuated for 1hr under vacuum pump to regenerate the adsorbent (nanozeolite). after the pre-treated of adsorbent, the vacuum pump was powered off. then carbon dioxide and nitrogen (10/90 v/v) were introduced and the inlet gases flow rate was measured by rotameter and then the gases entered the mixer column and to the adsorber vessel to begin the adsorption process. the outlet gas from the adsorption column was analyzed by gas analyzer periodically (each 5 sec) until reaching equilibrium. fig. 3: photographic picture of apparatus used for adsorption kinetics results and discussion 1. adsorption isotherm adsorption isotherm is basically important to describe how adsorbates interact with adsorbents, and is critical in optimizing the use of adsorbents [11]. adsorption isotherm study was carried out in three isotherm models, namely the langmuir, freundlich and temkin isotherms their equations were as follows: langmuir model http://www.iasj.net/ study the performance of nanozeolite naa on co2 gas uptake 62 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net freundlich model ⁄ temkin model qe= lna + lnce where qm (mmol/g) is the maximum loading corresponding to complete coverage of the surface by the gas and kl (l/mmol) is the adsorption equilibrium constant. ce (mmol/l) is the equilibrium concentration of the adsorbate qe is the amount adsorbed at equilibrium, kf are the freundlich constants n = the degree of nonlinearity. a (l/mmol) is the temkin isotherm constant related to equilibrium energy,  (j/mol) is the heat of adsorption. table 2 shows the three isotherm models used with all the constants and r 2 values obtained from each plot for naa nano-zeolite at 309 k and 333 k. this table shows that for carbon dioxide adsorption on nano zeolite naa the highest correlation coefficient (r 2 ) value is for the langmuir isotherm as compared to that of both freundlich and temkin isotherms at 309 k and 333k. figures 4 and 5 show the adsorption equilibrium isotherm of pure co2 on naa at 309˚k and 333˚k respectively correlated with langmuir equation. fig. 4: adsorption equilibrium isotherm of pure co2 on naa at 309˚k correlated with langmuir equation fig. 5: adsorption equilibrium isotherm of pure co2 on naa at 333˚k correlated with langmuir equation 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0 50 100 150 200 250 300 a m o u n t a d so r b e d q (m m o l/ g ) gas phase concentration c (mmol/l) exp. langmuir 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0 50 100 150 200 250 a m o u n t a d so r b e d q (m m o l/ g ) gas phase concentration c (mmol/l) exp. langmuir http://www.iasj.net/ http://www.scialert.net/fulltext/?doi=jas.2010.2565.2571&org=11#t1 najwa saber majeed and jwan taher majeed -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 63 table 2: isotherm parameter for carbon dioxide adsorption on nano zeolite naa isotherms parameters temperature (k) 309 333 langmuir qm kl r 2 5.0761 0.00063 0.999 1.5432 0.000222 0.995 freundlich kf n r 2 0.0043 1.0834 0.997 0.00695 1.2531 0.978 temkin kt  r 2 0.00038 0.296 0.959 0.0437 0.206 0.980 2. effect of temperature figure 6 shows the effect of temperature on adsorption isotherm for carbon dioxide on naa nano zeolite. from this figure, it is seen that increasing the equilibrium adsorption temperature decreases the total amount adsorbed on both adsorbents and hence, the capacities of these adsorbents. therefore, the adsorption of co2 onto nano zeolite mostly followed the exothermic nature of the adsorption process. with the increase in temperature, the adsorbed co2 becomes unstable on the nano zeolite surface because of increased molecular diffusion, which leads to more desorption of co2 molecules. this behavior has also been mentioned by [7]. fig. 6: adsorption equilibrium isotherm of carbon dioxide on naa nano zeolite adsorption kinetics (breakthrough curves) effect of feed flow rate the effect of co2 flow rate on the breakthrough curve on naa nano zeolite is shown in figures 7, 8 and 9. it can be seen that increasing the flow rate of the feed decreases breakthrough time and therefore the amount of co2 that can be adsorbed. when the flow rate was increased from 0.5 l/min to 2 l/min the time required for complete column saturation decreased from 160 s to 100 s for 15 g of naa zeolite and from 375 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0 50 100 150 200 250 300 a m o u n t a d so r b e d q ( m m o le /g ) gas phase concentration c(mmole/l) t=309k t=333k http://www.iasj.net/ study the performance of nanozeolite naa on co2 gas uptake 64 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net min to 285 min for 30 g of naa zeolite and from 470 to 400 for 60 g. in particular, a less sharp breakthrough curve is obtained at the highest flow rate tested, indicating poor utilization of the column capacity. the use of high flow rates reduces the time that adsorbate are in contact with the adsorbent, thus allowing less time for adsorption to occur, leading to an early breakthrough of adsorbate. in addition longer breakthrough times are desired, because this required less frequent need for regeneration of the adsorbent particles which in terms affect the amount of energy and cost of process operation. this behavior has also been mentioned by wu et. al. [12]. fig. 7: the effect of feed flow rate on the breakthrough time for (10% co2, 90%n2 at 309k and 15g of naa nanozeolite) fig. 8: the effect of feed flow rate on the breakthrough time for (10% co2, 90%n2 at 309k and 30g of naa nanozeolite) 0 0.2 0.4 0.6 0.8 1 1.2 0 25 50 75 100 125 150 175 c o u t/ c in time (sec) 0.5 l/min 1 l/min 2 l/min 0 0.2 0.4 0.6 0.8 1 1.2 -50 50 150 250 350 450 c o u t/ c in time (sec) 0.5 l/min 1 l/min http://www.iasj.net/ najwa saber majeed and jwan taher majeed -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 65 fig. 9: the effect of feed flow rate on the breakthrough time for (10% co2, 90%n2 at 309k and 60g of naa nanozeolite) the effect of amount of adsorbent since, the diameter of the adsorption column is constant; therefore the used weight of adsorbent corresponds to different bed lengths. the use of short bed length leads to shorten the contact time between the adsorbate and adsorbent and reduces the available area to transfer. figures 10, 11 and 12 show the effect of bed length on the breakthrough time, from these figures show that the adsorption capacity increases by bed length increasing for adsorption carbon dioxide, because the increase in bed length leads to increasing in the surface area available for adsorption. this behavior has also been mentioned by grande [13]. fig. 10: the effect of bed length on the breakthrough time for (10% co2, 90%n2 at 309k and 0.5 l/min of co2) 0 0.2 0.4 0.6 0.8 1 0 50 100 150 200 250 300 350 400 450 500 550 c o u t/ c in time (sec) 0.5 l/min 1 l/min 2 l/min 0 0.2 0.4 0.6 0.8 1 0 50 100 150 200 250 300 350 400 450 500 c o u t/ c in time (sec) 15 g 30 g 60 g http://www.iasj.net/ study the performance of nanozeolite naa on co2 gas uptake 66 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net fig. 11: the effect of bed length on the breakthrough time for (10% co2, 90%n2 at 309k and 1 l/min of co2) fig. 12: the effect of bed length on the breakthrough time for (10% co2, 90%n2 at 309k and 2 l/min of co2) conclusions carbon dioxide adsorption are investigated and the following were concluded 1equilibrium isotherm for pure co2 is fitted with the langmuir isotherm at 309 k and at 333 k. 2the effect of temperature showed that when temperature increases the adsorbed co2 decrease proving that the adsorption process is exothermic. 3effect of feed flow rate for mixture co2 and n2 on breakthrough curves showed that when the flow rate was increased from 0.5 l/min to 2 l/min the time required for complete column saturation decreased from 150 sec to 100 sec. 0 0.2 0.4 0.6 0.8 1 0 50 100 150 200 250 300 350 400 450 500 c o u t/ c in time (sec) 15 g 30 g 0 0.2 0.4 0.6 0.8 1 0 50 100 150 200 250 300 350 400 450 c o u t/ c in time (sec) 15 g 30 g http://www.iasj.net/ najwa saber majeed and jwan taher majeed -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 67 4the adsorption capacity increases by bed length increasing for adsorption carbon dioxide. references 1. yu, c.h., huang, c.h. and tan, c.s., 2012. a review of co2 capture by absorption and adsorption”. aerosol air qual. res, 12 (5), pp.745-769. 2. sabouni, r., 2013.carbon dioxide adsorption by metal organic frameworks (synthesis, testing and modeling). (doctoral dissertation, university of western ontario). 3. galhotra, p.,2010. carbon dioxide adsorption on nanomaterials. (doctoral dissertation, university of iowa). 4. mondal, m.k., balsora, h.k. and varshney, p.,2012. progress and trends in co 2 capture/separation technologies: a review. energy, 46 (1), pp.431-441. 5. siriwardane, r.v., shen, m.s., fisher, e.p. and poston, j.a., 2001. adsorption of co2 on molecular sieves and activated carbon. energy and fuels, 15 (2), pp.279-284. 6. shi, y., liu, q. and he, y.2015. co2 capture using solid sorbents. 7. pham, t.h., lee, b.k. and kim, j, 2016. novel improvement of co2 adsorption capacity and selectivity by ethylenediamine-modified nano zeolite. journal of the taiwan institute of chemical engineers. 8. pham, t.h., lee, b.k., kim, j. and lee, c.h. 2016. enhancement of co2 capture by using synthesized nano-zeolite. journal of the taiwan institute of chemical engineers, 64, pp.220-226. 9. luciano s. r., 2012. structured zeolite adsorbents for co2 separation, msc. thesis, college of engineering, luleå university of technology. 10. shakarova, d., ojuva, a., bergström, l. and akhtar, f., 2014. methylcellulose-directed synthesis of nanocrystalline zeolite naa with high co2 uptake. materials, 7 (8), pp.5507-5519. 11. tan, i.a.w. and hameed, b.h., 2010. adsorption isotherms, kinetics, thermodynamics and desorption studies of basic dye on activated carbon derived from oil palm empty fruit bunch. journal of applied sciences, 10, pp. 2565-2571. 12. wu, x., xu j., tao j., 2013.13xapg granular zeolite in a fixed bed adsorber of co2 adsorption characteristics. new york science journal, 6 (11), pp.33-37. 13. grande, c.a., cavenati, s. and rodrigues, a.e., 2005. “pressure swing adsorption for carbon dioxide sequestration”. in 2nd mercosur congress on chemical engineering and 4th mercosur congress on process systems engineering. http://www.iasj.net/ iraqi journal of chemical and petroleum engineering vol.12 no.3 (september 2011) 1-10 issn: 1997-4884 vapor-liquid-liquid equilibrium (vlle) data for the systems ethyl acetate + water, toluene + water and toluene + ethyl acetate + water at 101.3 kpa. using modified equilibrium still ghazwan a. mohammed, mahmoud o. abdullah and talib b. kashmoula al-nahrain university, chemical engineering department, baghdad, iraq isobaric vapor-liquid-liquid equilibrium data for the binary systems ethyl acetate + water, toluene + water and the ternary system toluene + ethyl acetate + water were determined by a modified equilibrium still, the still consisted of a boiling and a condensation sections supplied with mixers that helped to correct the composition of the recycled condensed liquid and the boiling temperature readings in the condensation and boiling sections respectively. the vlle data where predicted and correlated using the peng-robinson equation of state in the vapor phase and one of the activity coefficient models wilson, nrtl, uniquac and the unifac in the liquid phase and also were correlated using the peng-robinson equation of state in both the vapor and liquid phases. introduction industrial distillations involve many azeotropic systems with partial miscible regions for which a few data are available. an adequate method to determine the vapor liquid equilibrium (vle) data of such systems is of great importance. in both processes of azotropic distillation and liquid-liquid extraction, the solvent is generally removed from one or more streams by stripping columns from which the condensed overhead separates into two layers [1]. there are two major difficulties in studying partially miscible and immiscible systems in addition to those in equilibrium stills. the first is the vapor, when condensed it forms an immiscible mixture. thus the recirculation type apparatus can not be used since the condensed vapor cannot be returned to the boiler of the still with the two liquid phases in proper portions. the second difficulty lies in the great difference in composition between the vapor and liquid. for example, in the miscible region of ethyl acetate(1) + water(2), which extends to a mole fraction of x1 = 0.02. the vapor is from 5 to 22 times as rich in ethyl acetate as the liquid. therefore, if an equilibrium study is undertaken where a liquid sample is distilled, its composition will change extremely rapidly as vapor is formed, and the arrival at the desired steady state in the still becomes difficult [2]. the equilibrium data of the above systems are best correlated or predicted by the aid of activity coefficient models [3]. although attempts have been made by the equations of state (eos) [4, 5] which gave good results for high pressure immiscible systems but failed for low pressure systems. the most applied activity coefficient models are the wilson, nrtl, uniquac and the unifac models. all these models except the unifac have adjustable parameters obtained from non linear regression of experimental equilibrium data [6]. the nrtl model has three adjustable parameters. it has one parameter more than the other models. this increases the accuracy of the correlation and the prediction of equilibrium data. the scope of this paper involves the following university of baghdad college of engineering iraqi journal of chemical and petroleum engineering vapor-liquid-liquid equilibrium (vlle) data for the systems ethyl acetate + water, toluene + water and toluene + ethyl acetate + water at 101.3 kpa. using modified equilibrium still 2 ijcpe vol.12 no.3 (september 2011) -available online at:www. iasj.net objectives: assembling a modified equilibrium still to deal with partial miscible and immiscible systems. measuring the vapor-liquid-liquid equilibrium (vlle) data of the partial miscible binary system of ethyl acetate + water and the immiscible binary system of toluene + water and the ternary system of toluene + ethyl acetate + water in the new modified still at p = 101.325 kpa. correlating and predicting the vlle data obtained from the new modified still by applying the peng-robinson (eos) in the vapor phase and applying the activity coefficient models (wilson, nrtl, uniquac and unifac) in the liquid phase. experimental section materials. the chemicals used were supplied by bdh. all chemicals were used without further purification. table 1 lists the specification of the chemicals used. equilibrium still. the still used is a vapor circulation type similar to othmer still [7] as shown in figure 1. some modifications were made to the still to allow its use with partially miscible systems. the modifications helped in giving a steady temperature reading in the boiling section and helped in keeping the condensed vapor in the condensing section in a semi homogenous state. the modifications include mechanical mixers with multi-impeller shafts for both of the boiling section (boiler) and the condensation section (condenser), two reflux lines to return the condensed vapor to the boiler. the boiling and condensing sections are glass tubes (qvf) 55 and 40 cm in diameter respectively. the sections are connected with an inclined glass tube with a thermo well. the reflux lines are 1 mm capillaries. the heads of the sections are quick-fit type with polyethylene bushing seals to prevent vapor leakage. the sections were insulated with fiberglass insulation. the temperature in the boiling section is measured by a temperature sensor type nicr-ni and recorded and represented graphically via a cassy module interface through a pc (486) by the software universal data acquisition [8]. the speed of the mixers was also controlled through the same interface. the shafts were connected to the electric motors by rubber hoses to reduce the vibration of the motors. the shafts were operated at a speed of (1400 to 1600) rpm. vlle measurements. the still is charged with (200 to 300) ml of liquid of the desired composition. the heating mantle and the mixer in the boiling section are started via the software. when the liquid mixture starts to boil after (30 to 40) min the cooling water is allowed to flow in the condenser at a rate of 2 l.min -1 . as vapor starts to condense the mixer of the condensing section is started at a rate below vortex formation. after the temperature of the liquid mixture in the boiling section reaches a constant value after (70 to 80) min (monitored via the software display of temperature versus time), samples are withdrawn into a 5 ml graduated test tubes with 0.1 ml graduation and a sealed cap and then the heating is stopped. after (10 to 15) min the mixers and the cooling water are stopped also. lle measurements. the same still was used for lle measurements. after charging the still with 250 ml of liquid of the desired composition the heating mantle and the mixer in the boiling section are started via the software. when the temperature in the still reaches the desired value after (45 to 60) min, the mixer was stopped. after a period of 5 min, samples are withdrawn from each of the two liquid phases by a 0.1 ml pipette connected to a 10 ml glass syringe into a 5 ml graduated test tube with 0.1 ml graduation and a sealed cap. lle measurements were applied to the binary system ethylacetate(1) + water(2) only in the temperature range t = (25 to 65) o c. sampling methods. the withdrawn samples were (4 to 5) ml. three sampling methods were employed: 1. taking samples from condensed vapor and the ghazwan a. mohammed, mahmoud o. abdullah and talib b. kashmoula -available online at: www. iasj.net ijcpe vol.12 no.3 (september 2011) 3 boiling liquid [2], 2. taking a sample of the condensed vapor only [9] 3. the heating and mixing was stopped and a sample of the condensed vapor was taken immediately and a sample from each phase of the liquid in the boiling section as soon as the phases separate was also taken [10]. the withdrawn samples were placed in a water bath at a temperature of t = 20 o c and left overnight for complete separation of the liquid phases in each sample. then the volume of each phase was measured by the graduation on the test tube, with the solubility of each component at a temperature of t = 20 o c, a material balance was done to obtain the composition of the sample (two layer samples). sample analysis. most of the withdrawn samples were with two liquid phases (layers). for single layer samples, refractive indices of these samples were measured through an abbe-hilger refractometer at a temperature of t = 20 o c with an uncertainty of nd = ± 0.0001. two calibration curves were used to determine the mole fraction of the samples, one for the samples rich in organic component and one for rich in aqueous component below the solubility limits of the components. the curves were obtained by preparing liquid mixtures of different mole fractions for the samples and measuring the refractive index and the data obtained were best fitted. equations 1, 2 represent the system ethyl acetate (1) + water (2). )1(3526.1 0038.0 . orgn )2(3330.10072.0.  aqun where norg and naqu. are the refractive indices in the rich in organic and aqueous samples respectively and  is the mole fraction multiplied by 100 of ethyl acetate in the sample. the rich in organic sample of the system ethyl acetate (1) + toluene (2) + water (3) is given by equation 3. )3(3820.12001.0.  orgn the aqueous rich sample of the ternary system is also given by equation 2. the assumption of water not present in the organic rich sample of the ternary system is quite reasonable due to the low solubility of water in toluene, and toluene not present in the aqueous rich sample is also due to the low solubility of toluene in water. the binary system toluene(1) + water(2) was considered as an immiscible system. experimental data. the experimental data obtained from the vlle, lee measurements of the two binary and one ternary system are given in tables 2, 3, 4 and 5, where li is the composition of the initial liquid in the still as mole fraction of component i and t is the average boiling temperature of the temperatures recorded via the software, xi l , xi ll are mole fractions in top (organic) and bottom (aqueous) layers of component i, xi, yi are mole fractions in the liquid and vapor samples of component i. thermodynamic consistency test. the mcdermont-ellis test method [11] was used to test the experimental data given in tables 2, 4 and 5. the experimental data are thermodynamically consistent if the following condition is fulfilled: d < dmax (4) where d, dmax are the local and the maximum deviations defined else where[11]. table 6 lists the results of the test applied to the data in tables 2, 4 and 5. results and discussion temperature-composition diagrams. the data given in tables 2, 3, 4 and 5 are plotted in temperature-composition diagrams t,x1 o ,y1, t,x1 l ,x1 ll ,y1 and t, x1, x2, x3 as shown in figures 2, 3 and 4 [12]. x1 o is the overall mole fraction of component 1 in the liquid phase. prediction of equilibrium data. by applying equation 5 the value of the mole fraction in the vapor phase yi was determined: )5( sat i sat iiii v i pxpy   where φi v is the partial molar fugasity coefficient in the vapor phase which is determined from peng-robinson equation of state [13] with interacting parameters vapor-liquid-liquid equilibrium (vlle) data for the systems ethyl acetate + water, toluene + water and toluene + ethyl acetate + water at 101.3 kpa. using modified equilibrium still 4 ijcpe vol.12 no.3 (september 2011) -available online at:www. iasj.net kij=kji=0 and n=2. γi is the activity coefficient determined from activity coefficient models [13] and φi sat is the partial molar fugasity coefficient at saturation. pi sat is the vapor pressure given by antoine equation [13]. the parameters of the activity coefficient models (wilson, nrtl, uniquac and unifac) for the systems studied are taken from literature [6, 13-14]. the average absolute difference in vapor mole fraction iy of component ( i ) is given by equation 6. )6( )( 1 n yyabs y n pred ii i    where yi pred is the predicted vapor mole fraction determined from equation 5 and yi is the experimental vapor mole fraction and n number of data points in the system. table 7 lists the values of iy for the two binary and the ternary systems using the activity coefficient models, lll iy is the average absolute difference in the vapor mole fractions from the experimental data obtained by sampling method 3. the average absolute difference in the ratio of the activity coefficient in the top layer (γ1 l ) to the activity coefficient in the bottom layer (γ1 ll ) is )/(̀ lll  for the vlle and lle measurements is given by equation 7. )7( 1 1 1 1 1 1 1 n abs n pred ll l ll l ll l                                           where the ratio (γ1 l /γ1 ll ) was determined from the experimental ratio ( x1 ll / x1 l ) while the ratio (γ1 l /γ1 ll ) pred. was determined from the activity coefficients models mentioned previously. table 8 lists the values of )/(̀ lll  for the binary system ethyl acetate(1) + water(2). correlation of equilibrium data. the parameters of the activity coefficient equations wilson, nrtl and uniquac and the interacting parameters kij, kji and n of the peng-robinson equation of state were determined using a non-linear constraint optimization search. this was achieved by the aid of the software microsoft excel using the solver tool. the solver tool solves an optimization problem using the generalized reduced gradient (grg) search [15]. it first reduces the problem to an unconstrained optimization problem. it does this by solving a set of non-linear equations for the basic variables in terms of the non-basic variables. then the unconstrained problem is solved using the quasi-newton approach or the conjugate gradient approach. the following objective function and constraint was used: )8( 1 )( 11 1 11      c i c i i n j pred ijij y c yyabs nc )9(0,0 21   iiii yyyy where c is the number of components and n is the number of data points. the aim is to minimize equation 8 subject to the constraint of equation 9. the initial values to start the search were taken from the prediction method.. tables 9, 10 and 11 show the parameters of the activity coefficients determined from the correlation of the experimental data and 1y values for the two binary and the ternary systems. equation 5 can be written in the following form: )10( l iii v i xy   where φi l is the partial molar fugasity coefficient in the liquid phase. φi l was determined from peng-robinson equation of state (p.r. eos). table 12 lists the eos interacting parameters kij, kji and n for the two binary and the ternary systems with 1y determined by using these parameters. calculation of boiling temperature. the temperature of boiling was calculated by equation 11.      n i n i iv i l isat iii xppx 1 1 )11(1,/1    ghazwan a. mohammed, mahmoud o. abdullah and talib b. kashmoula -available online at: www. iasj.net ijcpe vol.12 no.3 (september 2011) 5 table 13 lists the values of the average absolute difference in temperature t of the two binary and the ternary systems by using the parameters from tables 9, 10, 11 and 12. t is defined the same as in equation 6. determination of azeotropic point. the azeotropic composition and temperature of the two binary and ternary systems were determined using the gibbs-konovalov theorem [16].table 14 lists the values of the azeotropic composition x1 azo and temperature t azo of these systems. discussion systems selected. two binary systems were selected, the system ethyl acetate + water is a system of limited miscibility where the solubility of ethyl acetate in water is 1 ml ethyl acetate in 10 ml water at 20 o c and the solubility of water in ethyl acetate is 1 ml water in 40 ml ethyl acetate at 20 o c [17]. the system toluene + water can be considered as an immiscible system where the solubility of toluene in water is 0.05 g toluene per 100 g water at 20 o c and the solubility of water in toluene is 0.03 g water per 100 g of toluene at 20 o c [17]. the mixtures of the two binary systems at boiling temperatures or above are three phase systems where two liquid phases in equilibrium with a vapor phase exist. the ternary system toluene +ethyl acetate + water consist of a miscible pair of toluene + ethyl-acetate and a partial miscible pair of ethyl-acetate + water and an immiscible pair of toluene + water. no vlle data are available in the literature for this ternary system [12]. assembled equilibrium still. an equilibrium still was assembled to deal with partial miscible and immiscible systems. the still was provided with mechanical mixers in both the boiling and condensing sections. the system ethyl acetate(1) + water(2) was studied by ellis et.al.[12] using an equilibrium still with mechanical agitation in both the boiling and condensing sections the equilibrium data obtained showed a constant vapor composition with a mole fraction of y1= 0.70 and a constant boiling liquid temperature of t = 70.5 o c in the boiling liquid composition with mole fraction range of x1= (0.05 to 0.78 ). also the data obtained by kato.m et.al.[6] showed a constant vapor composition with mole fraction of y1= 0.701 in the boiling liquid composition with mole fraction range of x1= (0.08 to 0.71) where an equilibrium still is similar to the othmer still with no mechanical agitation or mixing used. this indicates that mechanical mixing is necessary in both boiling and condensing sections and even agitation is not enough. the two reflux lines in the new still assured the return of the condensed vapor to the boiler in correct composition even if vortex occurred in the condenser due to the mechanical mixing. prediction method. the activity coefficient equations wilson, nrtl, uniquac and unifac and the pengrobinson (eos) were used to determine the value of yi theoretically by using the peng-robinson (eos) for vapor phase and by using one of the activity coefficient equations in liquid phase. the adjustable parameters of the first three activity coefficient equations were obtained from previous studies specially the two binary systems and for the ternary system the same adjustable parameters were used with the adjustable parameters of the binary system ethyl acetate + toluene obtained by correlating the experimental data of kropholler et.al.[6]. the nrtl activity coefficient equation gave the lowest y and )/( lll  as seen in tables 13 and 14; the nrtl equation has three adjustable parameters which give a better representation of the equilibrium data. the unifac method gave high y values; it has no adjustable parameters. the predicted parameters of the binary system toluene + water were in the temperature range t = (10 to 60) o c; very high average y values were obtained using these parameters as seen in table 13. correlation method. the adjustable parameters of the activity coefficient equations m.wilson, nrtl and uniquac and the interacting parameters vapor-liquid-liquid equilibrium (vlle) data for the systems ethyl acetate + water, toluene + water and toluene + ethyl acetate + water at 101.3 kpa. using modified equilibrium still 6 ijcpe vol.12 no.3 (september 2011) -available online at:www. iasj.net of the peng-robinson (eos) were determined by applying non-linear constrained optimization with the objective function given by equation 8 subjected to the constraint given by equation 9. the adjustable and interacting parameters used in the prediction method where used as initial values to start the search. the activity coefficient equations and the p.r.(eos) were used to determine the value of yi theoretically by using the later for the vapor and liquid phases the partial molar fugacity coefficients for both phases were determined with interacting parameters obtained by the correlation of the equilibrium data. and by using the p.r (eos) for vapor phase and using the activity coefficient equations in liquid phase, the adjustable parameters of the activity coefficient equations were obtained from correlation of equilibrium data. the parameters of the ternary system were obtained by using the adjustable and interacting parameters of the binary systems as initial values to start the search. the uniquac and the nrtl equations gave the lowest average y values for the binary systems and for the ternary system the uniquac equation gave the lowest average δyi values; these equations contain three adjustable parameters this gives a better representation of the equilibrium data. the p.r (eos) gave high average y values, according to the lattice model [3] which considers the liquid phase as a dense and highly nonideal-gas whose properties can be described by some (eos); this is not correct in vlle systems ( partial-miscible and immiscible ) were the liquid phases in equilibrium are highly non ideal systems. the average boiling temperature was determined theoretically by solving equation 11 for t where the newtonraphson method [18] was used with t exp. as the initial value to start the calculations. the uniquac equation gave low t values as shown in table 13. azeotropic point. the determination of the azeotrope point (x azo , t azo ) of partial and immiscible systems is very complex. such systems appear to have more than one azeotropic point especially minimum boiling mixtures where these mixtures boil at a temperature below the boiling point of any pure component in the mixture. usually the point with the lowest boiling temperature in the equilibrium data could be considered as the azeotropic point. in the present study two binary systems were studied, the system ethyl acetate(1) + water(2) showed a minimum boiling behavior at certain compositions as can be noticed from table 2 and figure 2 the data points t,y1 and t,x1 appear to meet in a straight line in the mole fraction range of x1, y1 = (0.50 to 0.80). the binary system toluene(1) + water(2) also showed a minimum boiling behavior as can be noticed from table 4 and in figure 3 the data points t-y1 and t-x1 appear to meet in a straight line in the mole fraction range of x1, y1 = (0.35 to 0.53). the ternary system toluene + ethyl-acetate + water showed a minimum boiling temperature as can be noticed in table 5 and figure 4. below the temperature contour of t = 79.81 o c lies mixtures with minimum boiling temperature especially the temperature contour of t = 76.35 o c. conclusions the modified still with mechanical mixing in both the boiling and condensation sections appeared to be suitable for vlle measurements of the binary systems ethyl acetate + water and toluene + water and the ternary system toluene + ethyl acetate + water. the same still was used for lle measurements of the binary system ethyl acetate + water. using equation 5 to predict or correlate vlle data gave the lowest y values than equation 6. the uniquac and nrtl models agreed better with the experimental vlle data than the other models. the nrtl model agreed well with the experimental lle data. acknowledgment gratitude is to the chemical engineering department of al-nahrain university for their support to this work. ghazwan a. mohammed, mahmoud o. abdullah and talib b. kashmoula -available online at: www. iasj.net ijcpe vol.12 no.3 (september 2011) 7 literature cited (1) colburn, a. p.; schoenborn, e.m. ; david shiling. equilibrium still for partially miscible liquids. ind.eng.chem. 1943, 35, 1250-1254. (2) ellis, s. r. m.; garbett, r. d. a new equilibrium still for the study of partially miscible systems. ind.eng.chem. 1960, 52, 385-388. (3) prausnitz, j. m.; lichtenthaler, r. n.; azevedo, e. g. molecular thermodynamics of fluid-phase equilibria; prentice hall: ptr, 1999. (4) peng, d. y.; robinson, d. b. two and three phase equilibrium calculations for systems containing water. canadian j. chem. eng. 1976, 54, 595-599. (5) carroll, j. j. ; mather, a. e. phase equilibrium in the system waterhydrogen sulphide: modelling the phase behavior with an equation of state. canadian j. chem. eng. 1989, 67, 9991003. (6) ohe, s. vapor-liquid equilibrium data; kodansha, 1989. (7) hala, e.; pick, j;. fried, v.; vilim, o. vapor-liquid equilibrium; pergamon press, 1958. (8) universal data acquisition program (525 032); leybold didactic gmbh,1998. (9) stockhardt, j. s.; hull, c. m. vaporliquid equilibria and boiling-point composition relations for systems nbutanol-water and isobutannol-water. ind. eng. chem. 1931, 23, 1438-1440. (10) chopade, s. p.; dhale, a. d.; clark, a. m.; kiesling, c. w.; myrant, l. k.; jackson, j. e.; miller, d. j. vapor-liquidliquid equilibrium (vlle) and vapor pressure data for the systems 2-methyl1,3-dioxolane (2md) + water and 2,4dimethyl-1,3-dioxolane (24dmd) + water. j. chem. eng. data 2003, 48, 4447. (11) prausnitz, j. m. molecular thermodynamics of fluid-phase equilibria; prentice hall, 1969. (12) mohammed, g. a. investigation of vapor-liquid-liquid equilibria; ph.d. thesis al-nahrain university: baghdadiraq, 2005. (13) assael, m. j.; trusler, j.p.; tsolakis, t. f. thermophysical properties of fluids an introduction to their prediction; imperial college press, 1996. (14) smith, j. m.; van ness, h. c.; abbott, m. m. introduction to chemical engineering thermodynamics; mcgrawhill, 1996. (15) edgar, t. f.; himmelblau, d. m. optimization of chemical processes; mcgraw-hill, 1988. (16) malesinski, w. azeotropy and other theoretical problems of vapor-liquid equilibrium; interscience, pwn:new york, 1965. (17) windholz, m.; budavari, s.; stroumtsos, l. y.; fertig, m. n. the merck index; merck & co, 1976. (18) gerald, c. f.; wheatly, p. o. applied numerical analysis;addisonwesley, 1989. tables table 1. specifications of the chemical used in the present work. table 2. experimental vapor-liquid-liquid equilibrium data for the system ethyl acetate(1) + water(2) at p = 101.325 kpa. l1 is the initial mole fraction of ethyl acetate in the still. . x1 l , x2 ll and x1 o chemical ethyl acetate toluene water assay ( mass fraction) 0.997 0.999 1.000 non volatile materials 0.000005 0.00001 ---- water content 0.0003 0.0003 ---- m 88.11 92.14 18.02 ρ , g.cm 3 0.901 0.867 0.998 nd 20 1.3763 1.4998 1.3334 vapor-liquid-liquid equilibrium (vlle) data for the systems ethyl acetate + water, toluene + water and toluene + ethyl acetate + water at 101.3 kpa. using modified equilibrium still 8 ijcpe vol.12 no.3 (september 2011) -available online at:www. iasj.net are the top, bottom and overall mole fractions of ethyl acetate in the liquid phase respectively. table 3. experimental liquid-liquid equilibrium data for the system ethyl acetate(1) + water(2) at p = 101.325 kpa. l1 is the initial mole fraction of ethyl acetate in the still. x1 l and x2 ll are the top and bottom mole fractions of ethyl acetate in the liquid phase respectively. l1 t , o c x1 l x1 ll 0.1559 24.80 0.9500 0.0187 0.1559 30.77 0.9500 0.0176 0.1559 34.27 0.9357 0.0172 0.1559 41.61 0.9165 0.0168 0.1559 49.68 0.8849 0.0170 0.1559 57.90 0.8291 0.0159 0.1559 65.33 0.8211 0.0172 sampling method 3 table4. experimental vapor-liquid-liquid equilibrium data for the system toluene (1) + water(2) at p = 101.325 kpa. l1 is the initial mole fraction of toluene in the still. x1 o is the overall mole fractions of toluene in the liquid phase. l1 t , o c x1 o y1 0.0167 98.08 0.0159 0.0564 0.0237 97.90 0.0214 0.0987 0.0536 96.95 0.0519 0.1435 0.0862 96.12 0.0810 0.2137 0.1452 94.60 0.1444 0.2776 0.2132 93.50 0.2058 0.3375 0.2940 92.61 0.2832 0.3675 0.3691 92.47 0.2698 0.4044 0.4422 92.49 0.4365 0.4806 0.5432 93.73 0.5478 0.5362 0.6174 94.97 0.6130 0.5769 0.7596 99.15 0.7614 0.6255 0.7615 99.34 0.7667 0.6437 0.8688 103.89 0.8813 0.7134 0.8947 107.26 0.9523 0.7856 0.9177 106.10 0.9288 0.7449 0.9494 108.54 0.9531 0.8301 sampling method 2 table 5. experimental vapor-liquid-liquid equilibrium data for the system toluene(1)+ ethyl acetate(2) + water(3) at p = 101.325 kpa. l1 and l2 are the initial mole fractions of toluene and ethyl acetate in the still respectively. x1 o and x2 o are the overall mole fractions of toluene and ethyl acetate in the liquid phase respectively. l1 l2 t , o c x1 o x2 o y1 y2 0.12 60 0.64 21 72.8 9 0.13 18 0.64 22 0.01 79 0.43 54 0.19 47 0.42 32 74.1 6 0.19 95 0.41 65 0.07 02 0.41 53 0.22 78 0.38 90 75.6 8 0.23 59 0.38 04 0.06 70 0.42 94 0.26 11 0.35 47 76.8 8 0.26 69 0.34 94 0.10 04 0.33 32 0.29 45 0.32 01 79.3 6 0.30 31 0.31 12 0.10 10 0.40 05 0.32 82 0.28 54 77.5 0 0.33 83 0.27 85 0.11 90 0.32 78 0.38 96 0.38 11 80.1 8 0.40 26 0.37 37 0.09 47 0.39 93 0.39 61 0.21 53 79.8 9 0.40 62 0.20 81 0.15 17 0.30 20 0.41 32 0.19 76 83.2 5 0.42 34 0.19 08 0.12 22 0.29 78 0.46 48 0.14 43 83.6 5 0.47 90 0.13 67 0.18 14 0.24 83 0.53 42 0.07 26 87.0 8 0.55 11 0.06 76 0.22 56 0.14 12 0.55 23 0.21 71 89.2 6 0.56 66 0.21 07 0.19 61 0.27 86 0.61 53 0.15 10 90.5 2 0.62 85 0.14 41 0.21 92 0.28 35 0.67 54 0.09 07 93.7 7 0.69 31 0.08 66 0.15 85 0.20 63 0.72 33 0.14 77 93.2 9 0.74 48 0.14 48 0.15 85 0.20 63 sampling method 2 table 6. results of the mcdermont-ellis test applied to the data in tables 2, 4, 5 and the data by ellis,etal.[2] d and dmax are the local and max. deviations defined else ware[11] system d dmax d < dmax ethyl acetate(1) + water(2) [2] 10.21 10.03 no ethyl acetate(1) + water(2) 7.08 9.52 yes toluene(1) + water(2) 12.36 13.62 yes toluene(1) + ethyl acetate(2) +water(3) 4.39 9.96 yes table7. the average absolute difference in vapor mole fraction y of the data in tables 2, 4, 5 and the l1 ta , 0 c x1 l x1 ll x1 o y1 0.0027 98.48 0.0003 0.0779 0.0099 96.92 0.0006 0.0813 0.0156 92.37 0.0065 0.0957 0.0242 84.53 0.0151 0.4468 0.0434 70.88 0.0304 0.4468 0.1018 71.38 0.7778 0.7806 0.2654 70.41 0.5531 0.7192 0.3384 72.96 0.5896 0.0166 0.3181 0.5086 0.4057 71.86 0.7869 0.0301 0.3880 0.6327 0.4723 71.26 0.7736 0.0120 0.4514 0.6680 0.5574 71.75 0.7898 0.0068 0.5413 0.6813 0.6689 71.28 0.6720 0.7369 0.7132 71.85 0.7310 0.7501 0.7964 73.42 0.9500 0.3257 0.7926 0.7898 0.8245 73.76 0.9500 0.7399 0.8239 0.8506 0.8878 74.80 0.9015 0.8510 0.8851 0.8528 0.9500 72.13 0.9500 0.9126 0.9840 76.37 0.9840 0.4767 sampling method 3 1 ghazwan a. mohammed, mahmoud o. abdullah and talib b. kashmoula -available online at: www. iasj.net ijcpe vol.12 no.3 (september 2011) 9 data by ellis,etal [2] using activity coefficient models with parameters taken from literature[6, 13-14]. system / y wilson nrtl uniquac unif ac toluene(1) + water(2) 0.214 0.685 0.269 ethyl acetate(1) + water(2) [2] 0.166 0.054 0.162 0.263 ethyl acetate(1) + water(2) 0.123 0.111 0.119 0.208 ethyl acetate(1) + water(2) 0.233 0.100 0.160 0.236 toluene(1) + ethylacetate(2) + water(3) 0.127 0.135 0.196 table 8. the average absolute difference in activity coefficient in the top layer to the activity coefficient in the bottom layer )/(̀ lll  for the vlle and lle data of the system ethyl acetate(1) + water(2) using activity coefficient models with parameters taken from literature[6, 13-14]. table 9. 1y and wilson parameters obtained by appling non-linear constraint optimization on the data in tables 2, 4 and 5. toluene(1) + ethylacetate(2) + water(3) toluene(1) + water(2) ethyl acetate(1) + water(2) wilson parameter 0.361 35550.1 1911.5 λ12 /k 222.9 193.3 573.3 λ21 /k -597.5 λ13 /k 181.1 λ23 /k 799.6 λ32 /k 1180.7 λ31 /k 0.061 0.101 0.116 1y table 10. 1y and nrtl parameters obtained by appling non-linear constraint optimization on the data in tables 2, 4 and 5. toluene(1) + ethylacetate(2) + water(3) toluene(1) + water(2) ethyl acetate(1) + water(2) nrtl parameter 0.649 0.632 0.505 α 33.8 415. 5 657.6 g12 /k 31.4 1515.1 1145 g21 /k 517.6 g13 /k 857.4 g23 /k 3071. 2 g32 /k 499. 9 g31 /k 0.060 0.075 0.069 1y table 11. 1y and uniquac parameters obtained by appling non-linear constraint optimization on the data in tables 2, 4 and 5. toluene(1) + ethylacetate(2) + water(3) toluene(1) + water(2) ethyl acetate(1) + water(2) uniquac parameter 4. 65 2.7 6. 06 z/2 428. 8 695 515 u12 /k 353. 5 -111. 8 30. 8 u21 /k 1087. 3 u13 /k 287 u23 /k 604. 3 u32 /k -144. 8 u31 /k 0.048 0.057 0.074 1y table 12. 1y and peng robinson (eos) interacting parameters obtained by appling non-linear constraint optimization on the data in tables 2, 4 and 5. toluene(1) + ethylacetate(2) + water(3) toluene(1) + water(2) ethyl acetate(1) + water(2) uniquac parameter 1. 96 1. 94 2.13 n 0. 055 0. 277 0. 271 k12 0. 083 0. 334 0. 222 k21 0. 163 k13 0. 049 k23 0. 045 k32 0. 025 k31 0. 072 0. 091 0. 213 1y table 13. the average absolute difference in temperature t of the two binary and the ternary systems by using the parameters from tables 9, 10, 11 and 12. toluene(1) + ethylacetate(2) + water(3) toluene(1) + water(2) ethyl acetate(1) + water(2) t / k 2. 120 2. 047 2.102 wilson 3. 455 1. 796 1. 817 nrtl 1. 902 1. 787 1. 513 uniquac 6. 219 5. 105 9. 480 unifac table 14. values of the azeotropic composition x1 azo and temperature t azo of the two binary and the system / measurement )/(̀ lll  wilson nrtl uniq uac unif ac ethyl acetate(1) + water(2) / vlle 0.061 0.019 0.041 0.186 ethyl acetate(1) + water(2) / lle 0.051 0.004 0.031 0.116 vapor-liquid-liquid equilibrium (vlle) data for the systems ethyl acetate + water, toluene + water and toluene + ethyl acetate + water at 101.3 kpa. using modified equilibrium still 10 ijcpe vol.12 no.3 (september 2011) -available online at:www. iasj.net ternary systems using the gibbs-konovalov theorem [16]. toluene(1) + ethylacetate(2) + water(3) toluene(1) + water(2) ethyl acetate(1) + water(2) azeotropic conditions 0. 153 0. 357 0. 517 x1 azo 0. 554 x2 azo 346. 44 365. 33 344. 31 t azo / k figures fig. 1. modified still with control: (1) computer, (2) interface, (3) temperature sensor, (4) heating mantle, (5) boiling section, (6) condenser, (7) electric motor, (8) voltage regulator, (9) cooling water inlet and outlet, (10) thermometer, (11) condensing section, (12) multi impeller shaft, (13) sampling valve, (14) vapor path. 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 280 300 320 340 360 380 mole fraction of ethyl acetate t / k fig. 2. experimental data for the system ethyl acetate (1) + water (2) at p =101.325 kpa : (■, □) liquid-liquid, data from table 3: (▲,∆) saturated vapor and liquid, data from table 2: ( — ) data correlated by uniquac equation with parameters from table 11. 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 364 366 368 370 372 374 376 378 380 382 384 386 t / k mole fraction of toluene fig. 3. experimental data for the system toluene (1) + water (2) at p =101.325 kpa: (▲,∆) saturated vapor and liquid, data from table 4: ( — ) data correlated by uniquac equation with parameters from table 11. fig. 4. experimental data for the system toluene (1) + ethyl acetate (2) + water (3) at p =101.325 kpa: (■) t, x1, x2, x3 data from table 5: ( ) t = 350 k contour: ( ) t = 360 k contour: ( ) t = 380 k contour : ( ) t = 370 k contour : ( ) t = 366 k [12]. 1 4 1 2 5 4 7 6 2 1 3 9 9 8 1 0 1 1 1 2 7 1 3 1 3 ijcpe vol.11 no.3 (september 2010) 15 iraqi journal of chemical and petroleum engineering vol.11 no.3 (september 2010) 15 22 issn: 1997-4884 using aluminum refuse as a coagulant in the coagulation and fliocculation processes hasan ferhood makki, ahmed faiq al-alawy, nada n. abdul-razaq and manal adnan mohammed chemical engineering department – college of engineering – university of baghdad – iraq. abstract the present work aims to study the efficiency of using aluminum refuse, which is available locally (after dissolving it in sodium hydroxide), with different coagulants like alum [al2 (so4)3.18h2o], ferric chloride fecl3 and polyaluminum chloride (pacl) to improve the quality of water. the results showed that using this coagulant in the flocculation process gave high results in the removal of turbidity as well as improving the quality of water by precipitating a great deal of ions causing hardness. from the experimental results of the jar test, the optimum alum dosages are (25, 50 and 70 ppm), ferric chloride dosages are (15, 40 and 60 ppm) and polyaluminum chloride dosages were (10, 35 and 55 ppm) for initial water turbidity (100, 500 and 1000 ntu) respectively. while, adding sodium aluminate with the coagulants (alum, fecl3 and pacl), the optimum dose of 50 ppm was enough for the reduction of turbidity and hardness of water. introduction treatment is provided to remove constituents from raw water which may pose a risk to public health or are undesirable in finished water. turbidity is a characteristic related to the concentration of suspended solid particles in water and has been adopted as an easy and reasonably accurate measure of overall water quality (1). the university of baghdad college of engineering iraqi journal of chemical and petroleum engineering using aluminum refuse as a coagulant in the coagulation and flocculation processes ijcpe vol.11 no.3 (september 2010) 16 coagulation-flocculation process is a major step in the production of potable water, allowing the removal of colloidal particles (2). the main difficulty is to determine the optimum coagulant dosage related to the characteristics of raw water. excessive coagulant overdosing leads to increased treatment costs and public health concerns, while underdosing leads to a failure to meet the water quality targets and less efficient operation of the water treatment plant (3). coagulation is the process of conditioning suspended solids particles to promote their agglomeration and produce larger particles that can be more readily removed in subsequent treatment processes (4). flocculation is the physical process of agglomerating small particles into larger ones that can be more easily removed from suspension. flocculation is almost always used in conjunction with, and preceded by coagulation. during the coagulation process the repulsive forces between solids particles are reduced or eliminated (5). chemicals commonly used in the coagulation process include aluminum or iron salts and organic polymers. the most common aluminum salts used for coagulation is aluminum sulfate (alum) and ferric chloride (fecl3). in addition, many types of polyaluminum coagulants are commercially available for water treatment, including polyaluminum chlorides (pacl), aluminum chlorohydrate (ach) and polyaluminum sulfates (pas) (6, 7). unlike alum, these products differ in their basicity and strength, and can contain small amounts of other substances, such as sulfate, silica and calcium. although these coagulants are used successfully in the field for water and wastewater treatment, their chemistry is not as well known as that of alum. coagulation mechanisms have not been studied extensively, and comprehensive guidelines on their selection and use do not exist (8). coagulation by itself does not achieve turbidity reduction; in fact turbidity may increase during the coagulation process due to the presences of insoluble compounds generated through chemical addition. the subsequent processes of flocculation, sedimentation, and filtration are used in conjunction with coagulation to achieve suspended solids and turbidity reduction (9). sodium aluminate is an important commercial inorganic chemical. it has been used as an effective source of aluminum hydroxide for many applications. the commercial importance of sodium aluminate is due to the versatility of its technological applications. in water treatment systems it is used as an adjunct to water softening systems, as a coagulant to remove suspended solids and some metals (cr, ba, cu), and for removing dissolved silica (10). in construction technology, sodium aluminate is employed to accelerate the solidification of concrete, mainly when working during frosty periods. it is also used in the paper industry, refractory brick production and alumina production, etc. furthermore, it is used as an intermediate in the production of zeolites for detergents, molecular sieves, adsorbents and catalysts (11). the main objective of this research is to study the effect of using aluminum refuse as a coagulant for the agglomeration and sedimentation of suspended solids and hardness removal. chemical reactions the aluminum refuse used in this study was dissolved in sodium hydroxide solution to produce 0.1m from sodium aluminate according to the following equation: 2al + 2naoh + 2h2o na2al2o4 + 3h2 sodium aluminate aids in the removal process, reacting with the precipitated hardness to form particles that can be removed more effectively. sodium aluminate, which is alkaline, releases hasan ferhood makki, ahmed faiq al-alawy, nada n. abdul-razaq and manal adnan mohammed ijcpe vol.11 no.3 (september 2010) 17 caustic soda and aluminum hydroxide as it dissolves in water: na2al2o4 + 4h2o 2al (oh) 3 + 2naoh na2al2o4 + ca (hco3)2 + 2h2o 2al (oh)3 + na2co3 + caco3 na2al2o +mg (hco3)2 + 4h2o 2al(oh)3 + 2nahco3 + mg(oh)2 the addition of alum (hydrated aluminum sulfate) to water produces insoluble aluminum hydroxide according to the reaction: al2(so4)3.18h2o + 6h2o 2al(oh)3 + 6h + + 3so4 2 + 18h2o the insoluble aluminum hydroxide forms the floc where the colloid particles are agglomerated on. while the addition of ferric chloride to water produces insoluble ferric hydroxide, according to the reaction: fecl3 + 3h2o fe(oh)3 + 3h + + 3cl aluminum and iron coagulants react with bicarbonate alkalinity (hco3) in acid drainage creating aluminum, ferric hydroxide flocs which attract metals in solution through coprecipitation. formation of hydroxide flocs with alum and ferric chloride can be represented by the following equations (12): al2(so4)3.18h2o+3ca(hco3)2 2al(oh)3 + 3caso4 + 6co2 + 18h2o al2(so4)3.18h2o+ 3mg(hco3)2 al(oh)3 + 3mgso4 + 6co2 + 18h2o 2fecl3 + 3ca(hco3)2 2fe(oh)3 + 3cacl2 + 7co2 2fecl3 + 3mg(hco3)2 2fe(oh)3 + 3mgcl2 + 7co2 materials and methods materials:  preparation of water samples: the addition of quantity of kaolin into the water vessel under manual agitation.  coagulants: alum [al2(so4)3.18h2o], ferric chloride [fecl3] and polyaluminum chloride (pacl) were used a long with the aluminum refuse. methods:  jar test apparatus: a conventional unit was used with six beakers, each 1000 ml in capacity.  hach surface scatter turbidimeter-5: to measure the turbidity of the samples throughout the experimental work in ntu unit.  ph meter (type ph 1100/ ph 2100): to measure the ph variation during the chemical reaction. procedure:  two main trails were conducted using three initial turbidity contents: 100, 500 and 1000 ntu.  the first sets of tests were to find the efficiency of turbidity removal using alum, ferric chloride and pacl as individual coagulants. the second trail was to test sodium aluminate with the above coagulants in the removal of turbidity.  the experimental work (jar test) was performed as: rapid mixing at 100 rpm for 2 min slow mixing at 25 rpm for 30 min allowing the suspension to settle for 30 min  samples were withdrawn from the top inch of each beaker for turbidity and ph measurements.  all the chemical tests and analysis were done according to standard method for the examination of water and wastewater (13). using aluminum refuse as a coagulant in the coagulation and flocculation processes ijcpe vol.11 no.3 (september 2010) 18 results and discussion the effect of different coagulants dosages (alum, fecl3 and pacl) on turbidity removal is shown in figs. 1, 2 and 3 for initial turbidities of 100, 500 and 1000 ntu respectively. these figs. show that the optimum dose for alum was 25, 50 and 70 ppm for 100, 500 and 1000 ntu turbidity respectively. while, for ferric chloride it was 15, 40 and 60 ppm and for polyaluminum chloride 10, 35 and 55 ppm for 100, 500 and 1000 ntu turbidity respectively. figs. 4 to 6 show the effect of adding sodium aluminate to alum, fecl3 and pacl on turbidity removal for the same initial turbidity concentration. in these experiments, the optimum dose for the three coagulants decreased by 50% when adding 20 – 50 ppm sodium aluminate to the tested water samples. as shown in these figures the final turbidity increased when adding more than 50 ppm of sodium aluminate. this may be explained by: particulates can be destabilized by adsorption of oppositely charged ions or polymer. most particulates in natural waters are negatively charged (clays, humic acids, bacteria) in the neutral ph range (ph 6 to 8); consequently, hydrolyzed metal salts and polyaluminum chloride can be used to destabilize particles through charge neutralization. when the proper amount of coagulant has adsorbed, the charge is neutralized and the particle will flocculate. when too much coagulant has been added, the particles will attain a positive charge and become stable once again. for coagulant dosages up to optimum value, the electrophoretic mobility becomes more positive and the amount adsorbed increases. higher dosage causes charge reversal, particle stability, and a higher residual turbidity (14). at the optimum dosage of coagulant, the particle charge is just neutralized and the collision efficiency reaches a maximum value. calcium carbonate hardness is a general term that indicates the total quantity of divalent salts present and does not specifically identify whether calcium, magnesium and/or some other divalent salt is causing water hardness. figs. 7, 8 and 9 illustrate the effect of the coagulants on hardness variation for different turbidities in the water samples. 0 5 10 15 20 25 0 10 20 30 40 50 coagulants dosage (ppm) f in a l t u rb id u ty ( n t u ). alum ferric chloride pacl fig. 1 effect of coagulants dosage on turbidity removal (initial turbidity = 100 ntu) 0 10 20 30 40 20 30 40 50 60 70 coagulants dosage (ppm) f in a l t u rb id u ty ( n t u ). alum ferric chloride pacl fig. 2 effect of coagulants dosage on turbidity removal (initial turbidity = 500 ntu) hasan ferhood makki, ahmed faiq al-alawy, nada n. abdul-razaq and manal adnan mohammed ijcpe vol.11 no.3 (september 2010) 19 15 25 35 45 55 40 50 60 70 80 90 coagulants dosage (ppm) f in a l t u rb id u ty ( n t u ). alum ferric chloride pacl fig. 3 effect of coagulants dosage on turbidity removal (initial turbidity = 1000 ntu) 0 2 4 6 8 10 20 30 40 50 60 70 80 90 100 sodium aluminate dosage (ppm) f in a l t u rb id u ty ( n t u ). alum (12 ppm) pacl (5 ppm) ferric chloride (8 ppm) fig. 4 effect of sodium aluminate dosage on turbidity removal for different coagulants (water turbidity = 100 ntu, ph = 7.6, hardness as caco3 = 56 mg/l) 0 5 10 15 20 25 10 20 30 40 50 60 70 80 90 100 sodium aluminate dosage (ppm) f in a l t u rb id u ty ( n t u ). alum (25 ppm) ferric chloride (20 ppm) pacl (17 ppm) fig. 5 effect of sodium aluminate dosage on turbidity removal for different coagulants (water turbidity = 500 ntu, ph = 8, hardness as caco3 = 83 mg/l) 0 10 20 30 40 50 10 20 30 40 50 60 70 80 90 100 sodium aluminate dosage (ppm) f in a l t u r b id u ty ( n t u ) . alum (35 ppm) ferric chloride (30 ppm) pacl (27 ppm) fig. 6 effect of sodium aluminate dosage on turbidity removal for different coagulants (water turbidity = 1000 ntu, ph = 8.3, hardness as caco3 = 120 mg/l) using aluminum refuse as a coagulant in the coagulation and flocculation processes ijcpe vol.11 no.3 (september 2010) 20 3 6 9 12 15 18 21 10 20 30 40 50 60 70 80 90 100 sodium aluminate dosage (ppm) f in a l h a r d n e s s a s c a c o 3 m g /l ferric chloride (8 ppm) alum (12 ppm) pacl (5 ppm) fig. 7 effect of sodium aluminate dosage on hardness for different coagulants (water turbidity = 100 ntu, ph = 7.6, hardness as caco3 = 56 mg/l) 14 18 22 26 30 34 38 10 20 30 40 50 60 70 80 90 100 sodium aluminate dosage (ppm) f in a l h a r d n e s s a s c a c o 3 m g /l ferric chloride (20 ppm) alum (25 ppm) pacl (17 ppm) fig. 8 effect of sodium aluminate dosage on hardness for different coagulants (water turbidity = 500 ntu, ph = 8, hardness as caco3 = 83 mg/l) 25 30 35 40 45 50 10 20 30 40 50 60 70 80 90 100 sodium aluminate dosage (ppm) f in a l h a r d n e s s a s c a c o 3 m g /l ferric chloride (30 ppm) alum (35 ppm) pacl (27 ppm) fig. 9 effect of sodium aluminate dosage on hardness for different coagulants (water turbidity = 1000 ntu, ph = 8.3, hardness as caco3 = 120 mg/l) conclusion 1. adding sodium aluminate with other coagulants such as alum, ferric chloride and pacl in water treatment had a significant effect, which is summarized as: 2. the optimum dose of the coagulants decreased by 50% and high turbidity removal was obtained. 3. the hardness of the tested water decreased to low concentrations. 4. this addition speeds up the coagulation processes which may decrease the treatment time. 5. reduced amounts of coagulant dose may reduce the cost of the treatment process. hasan ferhood makki, ahmed faiq al-alawy, nada n. abdul-razaq and manal adnan mohammed ijcpe vol.11 no.3 (september 2010) 21 nomenclature symbol definition a aluminum cl chloride p poly pacl polyaluminum chloride references 1. tseng, t., segal, b.d., and edwards, m. 2000. increasing alkalinity to reduce turbidity. journal of the american water works association. 92: 44-52. 2. edzwald, j.k., 1993. coagulation in drinking water treatment: particles, organics, and coagulants. water science technology 27(11), 21–35. 3. casey, t.j., 1997. unit treatment processes in water and wastwater engineering. wiely & sons, inc. 4. awwa. 1990. water quality and treatment. 4th ed. mcgraw-hill, inc. 5. csempesz, f., 2000. enhanced flocculation of colloidal dispersions by polymer mixtures. chem. eng. j. 80, 43–49. 6. dempsey, b.a., sheu, h., tanzeer, t.m., and mentink, j., 1985. polyaluminum chloride and alum coagulation of clay-fulvic acid suspensions. journal of american water works association 77(3): 74-80. 7. coagulation with polyaluminum coagulants – mechanisms and selection guidelines. ph.d. thesis, dept. of civil and amherst, university of massachusetts. 8. edzwald, j.k., and tobiason, j.e., 1999. enhanced coagulation: usa requirements and a broader view. water science technology 40(9), 63–70. 9. kawumara, s., 1991. integrated design of water treatment facilities. john wiley & sons, inc. 10. raymond, d.l., 1999. water quality and treatment a handbook of community water supplies. mcgrawhill, inc., 5th ed. 11. shemin, h., 2003. method for preparing sodium metaaluminate solution for synthesis of zeolite with diasporite. chinese patent, no. 401577. 12. faust, s.d., and aly, o.m., 1999. chemistry of water treatment: new york, lewis publishers. 13. apha-awwa-wpcf, 1995. standard methods for the examination of water and wastewater. 18th ed. american public health association. washington, d.c.u.s.a. 14. john, c.c., rhodes, r.t., david, w.h., kerry, j.h., and george, t., 2005. water treatment: principles and design. john wiley & sons, inc., 2nd ed. using aluminum refuse as a coagulant in the coagulation and flocculation processes ijcpe vol.11 no.3 (september 2010) 22 [al2(so4)3.18h2o]fecl3(pacl) ijcpe vol.11 no.2 (june 2010) iraqi journal of chemical and petroleum engineering vol.11 no.2 (june2010) 43-48 issn: 19974884 effect of the forming conditions in the production of gamma alumina catalyst support on the crushing strength property alaa dhari jawad, ibrahim richeh, and riad ahmed saleh chemical engineering departmentcollege of chemical and petroleum engineeringal-baath universitysyria abstract an investigation was conducted for the determination of the effects of the forming conditions in the production of gamma alumina catalyst support on the crushing strength property. eight variables were studied , they are ;binder content which is the sodium silicate , solvent content which is the water, speed of mixing , time of mixing, drying temperature , drying time , calcinations temperature and the calcinations time design of the experiments was made by using the response surface method in minitab 15 software which supply us 90 experiments . the results of this investigation show that the crushing strength for the dried gamma alumina extrudate was affected by the drying temperature and the drying time only and there is no interaction effect between the variables studied. furthermore, the results show that, the crushing strength for the calcined extrudate was affected by the speed of mixing only and the optimum speed is 900rpm. the maximum crushing strength of 38.38 after calcinations and 11.865 kg/mm after drying were obtained keywords: gamma alumina, catalyst support, crushing strength. _____________________________________________________________________ introduction the physical characteristics of the naphtha reforming catalysts are determined primarily by the material which serves as a support for the metal or bimetallic function. alumina is the support for nearly all reforming catalysts .the strength of the macroscopic catalyst particles is an important property. for most fixedbed operations, if a catalyst can survive the handling during manufacturing and loading, it has adequate strength [1]. the physical strength parameters of the catalysts, such as crushing strength and resistance to abrasion, are of significant importance. in industrial reactors, a catalyst with greater abrasion and crumbling tendency can cause severe pressure drop in reactors and pipe lines. changes in the environment inside the reformer caused by physical degradation of the catalyst adversely affect the the selectivity, activity, and ultimately the life of the catalyst [1]. the crush strength is the resistance of a solid to compression, a property of paramount importance not only for industrial catalysts, but also for ceramics, pharmaceutical tablets and many other solid materials. in the case of catalysts, it is noteworthy that many plant shutdowns occur due to mechanical failure of the catalyst (and not due to its loss of activity) [2]. as far as catalysts are concerned, the astm standard methods d 4179 and d6175 are recommended. d 4179 refer to tableted pellets which can be measured in either axial or radial way. as the axial crush strength is much higher, it is not representative of the catalyst behavior in the reactors, therefore the radial crush strength must be measured for industrial purposes (the type of the crush strength measured must always be specified).d 6175-98 procedure refers to extrudates (the radial measurements can be only performed in this case).the radial crush strength is usually expressed in kg/mm [2]. the crush strength of a catalyst is not appreciably dependent on reactor loading , but mainly on reactor operation .when the catalyst does not require activation , the crush test should be conducted on fresh dried samples, when the catalyst has to be activated in the reactor , only measurements on activated samples are significant [2]. university of baghdad college of engineering iraqi journal of chemical and petroleum engineering effect of the forming conditions in the production of gamma alumina catalyst support on the crushing strength property ijcpe vol.11 no.2 (june 2010) 44 single pellet radial or, for irregularly shaped particles, bulk crush strength must be measured for any catalyst used in fixed –bed and trickle-bed reactors. a minimum value of the force required to break the pellets is usually specified for single –pellet crush strength (such values should not refer to axial measurements) [2]. for bulk crush strength, either the minimum pressure giving 1% fines (astm d 7804-04) or the maximum percentage of fines formed under the pressure of 23 bar are specified [2]. the crushing strength of the alumina spheres measured by single –pellet radial is 7 kg minimum. without knowledge of the mechanical properties of the materials used, it is impossible to utilize high pressure, temperatures and rates which characterize the present day development of all industries [3]. contact masses experience different loads when operating under the conditions of fixed and supensed beds. under the conditions of a fixed bed, the grains are under the pressure of the overlying beds, i.e., they" work” for compression under the conditions of different temperatures and media .under the conditions of suspension , friction forces and to a certain extent impact forces act on the catalyst .taking account of the difference in the load, contact masses are tested likewise by different methods [3]. the purpose of this research is to show which of the variables participating in the forming of gamma alumina support has an effect on the mechanical characteristic of the support by measuring the radial crush strength of the extrudate. experimental work the variables that were studied in this work and which is participating in the steps of forming the gamma alumina supports from the gamma alumina powder are as shown in table 1 with the upper and the lower limit for each of them (based on gamma alumina powder) . table 1 details of the variables and its lower and upper limits no. variable lowe r limit upper limit 1 binder: sodium silicate (50% soln.) % 20% 50% 2 solvent: water % 70% 90% 3 speed of mixing ,rpm 300 1500 4 time of mixing,min 10 45 5 drying temperature,c o 100 200 6 drying time,min 30 120 7 calcination temperature, c o 300 700 8 calcination time,hr. 2 6 raw materials gamma alumina powder supplied from suzhou yuguang lighting materials co. ltd. from china was used with the properties shown in table 2 .the xrd chart for it is shown in fig. 1. table 2 properties of the gamma alumina powder no. specification value 1 name high purity alumina powder 2 type gamma-al2o3 3 purity% 99.99 4 particle size,µm 0.2 5 loose density, g/cm 3 0.16 6 bet,m 2 /g 120 7 k,ppm 30 8 na,ppm 18 9 fe,ppm 10 10 si,ppm 20 11 mg,ppm 10 12 mn,ppm 9 13 ti,ppm 10 14 cr,ppm 10 15 cr,ppm 10 16 zn,ppm 10 figure 1 xrd chart for the gamma alumina powder used commercial sodium silicate solution was used as a binder, its specific gravity is 1.500 and its concentration is 44% alaa dhari jawad, ibrahim richeh, and riad ahmed saleh ijcpe vol.11 no.2 (june 2010) 45 gamma alumina extrudate manufacturing steps figure 2 show the steps used in making the alumina paste and forming the extrudate for the support [4]. figure 2 block diagram of the steps used in producing the gamma alumina extrudate (support) method of moulding there are many methods to mould the catalyst supports [3], in this work the gamma alumina paste was rubbed into the aperture of perforated steel plate. the size of granules produced is determined by the thickness of the plate and the diameter of the aperture, this is the same as mentioned in reference [3]. design of experiments the response surface method from the minitab 15 software was used to get the table of design for the 8 variables mentioned above, 90 experiments were got from the minitab software [5,6] . from each experiment two samples was tested for crush strength , one after drying and other after calcination, so from the 90 experiments 180 samples were gotten and the crush strength was repeated 20 times for each sample, i.e. , 3600 single pellets were tested for the crushing strength according the standard method, astm d-6175-03 [7].each pellet length over diameter ratio was measured before test , to assure that the l/d is equal or greater than 1.1 as mentioned in the astm method above. results and discussion from the analysis of variance for the dried and calcined crush strength made by the minitab software, we get that there is a linear regression for the dried crush strength,also it appeared that there is no any interaction effects between the variables affect the crush strength for both the dried and calcined extrudate. the estimated regression coefficients for the dried crush strength show that drying temperature and the drying time were the only variables that affect the crush strength in dried state. figure 3 show the interaction effect for the two above variables on the dried crush strength. from figure 3 , it can be seen that the crush strength increased with increasing the drying time for each drying temperature .also we can see that the best drying time is between 90-120 minutes.the best drying temperature is between 150-200 c o . 120.00090.91075.00059.09030.000 11 10 9 8 7 6 5 4 3 2 drying time m e a n 100.000 132.322 150.000 167.678 200.000 temp drying interaction plot for crush strenght dried data means figure 3 the interaction plot of the drying temperature and drying time on the crush strength in dried extrudate figures 4 and 5 show that only the drying time and the drying temperature has clear affect on the mean crush strength. 50 .0 00 0 40 .3 03 3 35 .0 00 0 29 .6 96 7 20 .0 00 0 10.0 7.5 5.0 2.5 0.0 90 .0 00 0 73 .8 38 8 65 .0 00 0 56 .1 61 2 40 .0 00 0 15 00 .0 0 11 12 .1 3 90 0. 00 68 7. 87 30 0. 00 45 .0 00 0 33 .6 87 2 27 .5 00 0 21 .3 12 8 10 .0 00 0 10.0 7.5 5.0 2.5 0.0 20 0. 00 0 16 7. 67 8 15 0. 00 0 13 2. 32 2 10 0. 00 0 12 0. 00 0 90 .9 10 75 .0 00 59 .0 90 30 .0 00 sodium silic a te% m e a n w a ter % rpm time of mixing drying temp drying time main effects plot for crush strenght dried data means mixing ,wetting the mixture gamma alumina+water+sodium silicate granule moulding drying the extrudate calcination the extrudate effect of the forming conditions in the production of gamma alumina catalyst support on the crushing strength property ijcpe vol.11 no.2 (june 2010) 46 figure 4 the main effects plot for the crush strength dried figure 5 the main effect plot for the crush strength calcined. the estimated regression coefficients for the calcined crush strength show that speed of mixing is the only one variable that has a little affect on the crush strength in calcined state. . high crush strength values which is agree with the required minimum values of the alumina support (7kg/mm) obtained in the experiments shown in table 3.the detailed formulation conditions of the above experiments is shown in table 4. table 3 details of the experiments of high crush strength in the dried and claimed conditions. table 4 details of the formulation conditions for the high crush value experiments e x p e ri m e n t s o d iu m s il ic a te % w a t e r % r p m t im e o f m ix in g ,m in d r y in g t e m p ,c o d r y in g t im e ,m in c a l c in a t i o n t e m p ,c o t im e o f c a l c in a t i o n ,h r, 12 35 65 900 27.5 150 30 500 4.00 13 20 65 900 27.5 150 75 500 4.00 14 29.69 73 687.8 33.6 132. 90. 570 4.70 15 35 65 900 27.5 150 75 500 4.00 16 40.30 73 1112 21.31 132 59. 429 4.70 18 29.696 56 687 21.31 167 90. 570 4.70 24 29.69 73 1112 33.6 132 90. 429 4.70 31 40.30 73 1112 21.31 167 90. 429 4.70 34 29.69 73 1112 33.68 167 90. 429 3.29 37 35 65 900 45 150 75 500 4.00 figure 6, shows that the best concentration of sodium silicate which give high values of crush strength was 40.30%. 50.000020.000035.000040.303329.6967 180 160 140 120 100 80 60 40 20 0 sodium silicate% c r u s h s t r e n g h t c a l c in e d chart of crush strenght calcined figure 6 sodium silicate effect on calcined crush strength no experiment state crush value,kg 1 12 calcined 10.545 2 13 calcined 11.585 3 14 calcined 13.555 4 15 calcined 38.36 5 16 calcined 19.689 6 18 dried 11.865 7 24 calcined 13.875 8 31 dried 10.776 9 31 calcined 12.07 10 34 calcined 7.665 11 37 calcined 10.7042 50.000040.303335.000029.696720.0000 10 5 0 90.000073.838865.000056.161240.0000 1500.001112.13900.00687.87300.00 45.000033.687227.500021.312810.0000 10 5 0 200.000167.678150.000132.322100.000 90.909975.000059.090130.0000 700.000570.711500.000429.289300.000 10 5 0 6.000004.707114.000003.292892.00000 so d iu m s ilic a te % m e a n wa te r % rp m tim e o f m ixin g d ryin g te m p d ryin g tim e a lc in a tio n te m p tim e o f c a lc in a tio n main effects plot for crush strenght calcined data means alaa dhari jawad, ibrahim richeh, and riad ahmed saleh ijcpe vol.11 no.2 (june 2010) 47 figure 7, shows that the best water content which give high crush strength is 65 and 73%, it is compatible with the results of table 3 and 4. 40.000090.000065.000056.161273.8388 180 160 140 120 100 80 60 40 20 0 water % c r u s h s t r e n g h t c a l c in e d chart of crush strenght calcined figure 7 water content effect on calcined crush strength figure 8 show that the best speed of mixing which gives high crush strength is 900 rpm, it is compatible with the results of table 3 and 4. 300.001500.001112.13900.00687.87 180 160 140 120 100 80 60 40 20 0 rpm c r u s h s t r e n g h t c a l c in e d chart of crush strenght calcined figure 8 speed of mixing effect on calcined crush strength figure 9 show that the time of speed which gives high crush strength is between 21-33 minutes, it is compatible with the results of table 3 and 4. 10.000045.000033.687227.500021.3128 160 140 120 100 80 60 40 20 0 time of mixing c r u s h s t r e n g h t c a l c in e d chart of crush strenght calcined figure 9 main effect of the time of mixing on calcined crush strength. figure 10. shows that the range of the drying temperature which gives high calcined crush strength is 132-150 c o . 200.000100.000150.000167.678132.322 160 140 120 100 80 60 40 20 0 drying temp c r u s h s t r e n g h t c a l c in e d chart of crush strenght calcined figure 10 main effect of drying temperature on calcined crush strength figure 11 shows that the drying time which give high calcined crush strength is between 75-90 minutes, it is compatible with the results of table 3 and 4. 120.00030.00075.00059.09090.910 180 160 140 120 100 80 60 40 20 0 drying time c r u s h s t r e n g h t c a l c in e d chart of crush strenght calcined figure 11 main effect of drying time on calcined crush strength. figure 12 shows that the calcined time which give high calcined crush strength is 4 hours , it is compatible with the results of table 3 and 4. 6.000002.000003.292894.000004.70711 180 160 140 120 100 80 60 40 20 0 time of calcination c r u s h s t r e n g h t c a l c in e d chart of crush strenght calcined figure 12 main effect of the calcination time on effect of the forming conditions in the production of gamma alumina catalyst support on the crushing strength property ijcpe vol.11 no.2 (june 2010) 48 crush strength figure 13 shows that the calcination temperature which give high calcined crush strength is 500 c o . 700.000300.000570.711500.000429.289 180 160 140 120 100 80 60 40 20 0 alcination temp c r u s h s t r e n g h t c a l c in e d chart of crush strenght calcined figure 13 main effect of calcinations temperature on crushgt strength for dried crush strength the best results was obtained at the following operating conditions: a. sodium silicate solution concentration 40.30% b. water content 73% c. speed of mixing: 900 rpm. d. time of mixing 21 minutes e. drying temperature 167 c o . f. drying time 90 minutes. conclusions: 1. the drying time and the drying temperature are very important variables on the crush strength values of the gamma alumina extrudates while forming them. 2. the best drying temperature is between 150-167 c o ,whilethe best drying time is 1.5hours. 3. there is no interaction effect between the variables studied in forming the gamma alumina extrudate. 4. there is linear regression between the dried crush strength and the drying time and drying temperature. 5. calcination in general raise the crush strength of the dried extrudate to the required acceptable value. 6. the best calcination temperature and time of calcination are is 500 c o and 4h respectively. 7. the best mixing speed in the step of making the alumina paste and the time of mixing are is 900 rpm and 27 minutes respectively. references: 1. antos,george j., aitani, abdullah m.,parea,jose m., " catalytic naphtha reforming science and technology", marcel dekker inc.,usa,1995. 2. www.materialstechnologies.com 3. mukhlyonov,i.p.,dobkina, e.i,deryuzhkina,v.i,soroko,v.e.,"catalyst technology" ,mir publishers,moscow, 1976. 4. us, patent 4579728april,1 1986,wide pore alumina supports,. 5. statistics using spss, ray pub., syria,2007. 6. montgometry,"design and analysis of experiments", 1997. 7. astm method d-6175-03. http://www.materialstechnologies.com/ available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.20 no.1 (march 2019) 13 – 13 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: alyaa f. ali, email: alyaafaris94@gmail.com, ziad t. abd ali, email: z.teach2000@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. interaction of aqueous cu 2+ ions with granules of crushed concrete alyaa f. ali and ziad t. abd ali department of environmental eng., college of engineering, university of baghdad abstract the sorption of cu 2+ ions from synthetic wastewater using crushed concrete demolition waste (ccdw) which collected from a demolition site was investigated in a batch sorption system. factors influencing on sorption process such as shaking time (0-300min), the initial concentration of contaminant (100-750mg/l), shaking speed (0-250 rpm), and adsorbent dosage (0.05-3 g/ml) have been studied. batch experiments confirmed that the best values of these parameters were (081 min, 011 mg/l, 250 rpm, 0.7 g ccdw/100 ml) respectively where the achieved removal efficiency is equal to 100%. sorption data were described using four isotherm models (langmuir, freundlich, redlich-peterson, and radke-prausnitz). results proved that the pure adsorption and precipitation are the main mechanisms for removal of copper ions from aqueous solution onto ccdw and sorption data can be represented by langmuir and radke-prausnitz model. the copper ion was successfully removed from aqueous solution during batch experiments using ccdw in the particle size range 2–1 mm. scanning electron microscopy detected that the removal of cu 2+ was found to arise from surface precipitation. keywords: sorption, recycling, concrete demolition waste, heavy metal ion, isotherm received on 23/10/8108, accepted on 20/01/8108, published on 30/03/8109 https://doi.org/10.31699/ijcpe.2019.1.5 1introduction the contamination of water by toxic heavy metals through the discharge of industrial wastewater is a worldwide environmental problem. many branches of the industry nowadays generate large quantities of waste containing toxic and carcinogenic organic and inorganic compounds ‎[1]. the presence of heavy metals in streams, lakes, and groundwater reservoirs has been responsible for several health problems with plants, animals, and human beings ‎[2]. since copper is a widely used material, there are many potential sources of copper pollution such as plating, mining and smelting, brass manufacture, electroplating industries, petroleum refining, and it is used excessively in based agrichemicals mining ‎[3]. these industries produce much wastewater and sludge containing cu 2+ ions with various concentrations having negative effects on the water environment. although a limit of 2 mg/l was proposed by the world health organization as the provisional guideline value for copper content of drinking water, intake of excessively large doses of copper by man leads to severe mucosal irritation and corrosion, widespread capillary damage, hepatic and renal damage and central nervous system irritation followed by depression. severe gastrointestinal irritation and possible necrotic changes in the liver and kidney could occur ‎[4]. removal of toxic heavy metal ions from the environment is an important challenge. typically, a removal process must be simple, effective and inexpensive. thus, several processes have been employed heretofore including adsorption, chemical precipitation, reverse osmosis and ion exchange, coagulation and flocculation, biosorption and membrane process ‎[5]. lately, scientists have been studying the use of cheap and plentiful sorbents to remove heavy metals from wastewater. natural and industrial geomaterials and biosorbents are well-known sorbents, and researchers have done many tests to identify the adsorption capacity of those materials ‎[6]. rapid civilization, industrialization, and population growth in developing and developed countries produce millions of tons of construction and demolition waste (cdw) per year. consequently, researchers predict that countries will produce massive amounts of cdw materials in the future, creating many environmental problems. therefore, investigation of the efficient recycling and usage of those abundantly available resources for different activities is timely. the utilize of alkaline cement and another portland for the treatment and conditioning of sludge, liquid, and particulate wastes containing heavy metals is well decided. https://doi.org/10.31699/ijcpe.2019.1.5 a. f. ali and z. t. abd ali / iraqi journal of chemical and petroleum engineering 20,1 (2019) 10 – 18 23 „sorption‟ or ion exchange are the mechanisms implied immobilization of heavy metal ions by cement matrix and this process happens by the nanoporous hydration product, calcium silicate hydrate; lattice incorporation into crystalline components of the hydrated cement matrix and deposition of insoluble hydroxides and hydrated metal silicate salts ‎[6], ‎[8]. cement compounds can be chemically categorized as a highly heterogeneous material, thus, dissolved metals in the aqueous solution can be removed by adsorption and precipitation ‎[9], ‎[10]. in order to describe the precipitation phase and the simultaneous adsorption–precipitation phase it is favored to adopt a gradual operation manner for the description of these mechanisms. the variance between these phases can be clarified by the adsorption phase, as follows ‎[11]: precipitation by metal (m) hydrolysis x2o+h2o 2x (oh) (1) mso4 +x (oh) m(oh)2 +xso4 (2) where x : ca, mg, k; na; m : pb, cu, ni …etc adsorption of metal onto cement compounds (cc) particles m(oh)2 + ckd cc –{–m(oh)2} (3) accordingly, it is visualized that the basis of demolition waste is concrete maybe affect the removal of toxic pollutants from contaminant water current. the scientist announced herein has been conducted to examine crushed concrete demolition waste ccdw and to define the kind of the reaction of aqueous containing metal ion with it. it has been investigated in a batch sorption study the removal of heavy metals from contaminant aqueous solutions by the 2-1 mm fraction of ccdw, the granules of ccdw loaded metal ions were tested by scanning electron microscopy and energy dispersive x-ray analysis to define the kind of the ccdw–metal ion interactions. 2isotherm models in the current study, a range of isotherm models is used to simulate the performance of ccdw in removing heavy metals ions from wastewater. a summary of these models is presented below:  langmuir model: presume regular energies of sorption .upon the surface and no emigration of sorbate in the plane of the surface. it can be written as follows: (4) where: qm is the maximum sorption capacity (mg/g) and b is the constant related to the free energy of sorption (l/mg) ‎[12]. where: qe is the amount of adsorbate the where qm is the maximum sorption capacity (mg/g) and b is the constant related to the free energy of sorption (l/mg), ce is the equilibrium concentration (mg/l).  freundlich model: is quantified by: ⁄ (5) where is the freundlich sorption coefficient and n is an empirical coefficient indicative of the intensity of the sorption ‎[12].  redlich–peterson model: in some combination of both langmuir and freundlich features, a redlich– peterson isotherm comes like a hybrid isotherm model often utilize to represent solute adsorption data on heterogeneous surfaces with an incorporation of three parameters into an empirical equation as follows: (6) where kr, ar, and r are constants, the r takes the values ranged from 0 to 1. the redlich–peterson model is taken the form of the langmuir model when βr equal to 1, while it is reduced to the form of freundlich model for βr equal to 0 ‎[13].  radke–prausnitz model: this model is given as follows: (7) where: qmrp is the maximum adsorption capacity (mg/g), while krp and mrp are constants ‎[14]. 3experimental work 3.1. materials waste concrete was collected from a demolition site and then manually washed with tap water to remove any other undesirable material. it was crushed with miller, sieved into (2-1) mm, and then it was washed before being used with distilled water to remove fine powder and then dried. this was used for the batch experiments and characterization. the physical properties of the crushed concrete such as surface area=11.0956m 2 /g, bulk density=1.0481g/cm 3 , real density=2.6202g/cm 3 , and porosity=0.6 were measured at oil research and development center-ministry of oil. cu 2+ was selected as a representative of heavy metal contaminants. to simulate the water‟s copper contamination, the stock solution (1000 mg/l) of cu(no3)2.3h2o (manufactured by hamedia, india) was prepared by dissolving an appropriate quantity of metal salt in distilled water and then stored in a glass container at room temperature. 3.2. characterization of ccdw samples of ccdw were tested by energy dispersive xray analysis (edx) (tescan, vega iii, and the czech republic). a. f. ali and z. t. abd ali / iraqi journal of chemical and petroleum engineering 20,1 (2019) 10 – 18 22 energy dispersive x-ray analysis (edx) is a chemical microanalysis technique used in conjunction with scanning electron microscopy (sem) used to recognize the elemental composition of materials. the data that resulted from (edx) examination includes of spectrum showing crests identical to the elements that achieve true composition of the sample being analyzed ‎[15]. 3.3. batch experiments the batch experiments were conducted through a set of four experiments to identify the circumstances for the highest removal efficiency of the pollutant. these circumstances included shaking time, the initial concentration of contaminant, shaking speed and sorbent dosage. the first set included shaking time variation (0-300 min) at an initial concentration of contaminant, shaking speed and sorbent dosage of 250 mg/l, 200 rpm and 0.2 g ccdw/100 ml of contaminant solution respectively. the second set included a solution variation in the initial concentration of contaminant (100, 150, 250,500 and 750 mg/l) at an optimum time of shaking obtained from the results of the first set. while maintaining shaking speed and sorbent dosage at their former values. the third set included variation in shaking speed (0, 50, 100, 150, 200 and 250 rpm) at an optimum initial concentration of contaminant obtained from the outcome of the second set; while the value of the rest of the factors remained the same as in the second set. finally, the last set included a variation of ccdw dosage (0.05-3g/ml) with a chosen shaking speed obtained from the outcome of the third set; while the value of the rest of the factors remained the same as in the third set. in the experiments mentioned above, 250 ml flasks were utilized, wherein every flask 100 ml of contaminant solution with a certain amount of sorbent dosage were added. the flasks were shaken by an incubator shaker (iso 9001, model: lsi-3016, no.b110416002, korea). at the end of any specific experiment, 20 ml of solution sample pulled from the flask and subsequently filtered using filter paper. 10 ml sample was withdrawn from the filtered supernatant to determine the concentration of metal by using atomic absorption spectrophotometer (aas) (model: 210 vgp, usa). however, the efficiency of heavy metal removal (removal %) was calculated as follows: (8) where: co and ce are the initial and the equilibrium contaminant concentrations, respectively. r is the removal efficiency (%). from a mass balance it can be specified the amount of sorbed contaminant (qe) retained in the ccdw phase, by taking into consideration its initial and equilibrium concentrations, therefore pure sorption can be calculated: (9) where co and ce are the initial and equilibrium concentrations of the contaminant in the solution (mg/l), v is the amount of solution in the flask (l), and m is the weight of the adsorbent substance in the flask (g). 4results and discussion this section presents sets of batch mode experiments to examine the efficiency of copper removal from wastewater by the selected reactive material; the data obtained from these experiments have been subjected to four sorption isotherms namely langmuir and freundlich, redlich-peterson and radke-prausnitz models. the effect of many operating parameters such as shaking time, initial concentrations of cu 2+ , shaking speed and reactive material dosage was studied to choose the best conditions. 4.1. characterization of ccdw samples it is essential that the cement matrix of ccdw chosen for this study was adequately ancient because immature cement pastes contain an appreciable ratio of residual anhydrous phases and contain unrefined pore networks which may affect the nature of their interactions with heavy metal ions [16]. for this reason, new concrete was not used and ccdw was selected for old buildings. a corresponding energy dispersive x-ray (edx) spectrum confirmed the existence of ca, si, al, s, fe, mg, na, and k as the major components were found to be approximately 27.13%, 9.26%, 3.48%, 1.24%, 1.15%, 0.81%, 0.78%, 0.41% respectively. these elements are representative constituents of portland cement, therefore, constituent concentrations is different according to the ratio of phases existent in a given position, though, it must be indicated that hydrated cement is heterogeneous on a microscopic scale ‎[16]. 4.2. influence of batch operating parameters a. effect of shaking time the influence of shaking time on cu 2+ removal using 0.2 g ccdw add to 100 ml of contaminated solution with initial ph=4, as shown in fig. 1 the plot reveals that the rate of the percentage of metal ion removal is higher at the beginning and gradually starts to slow down afterward ‎[17]. that is probably due to diminishing in the sorption sites of the reactive material lead to slower sorption. as the active adsorption sites become exhausted, the uptake rate is controlled by the rate at which the adsorbate is transported from the exterior to the interior sites of the adsorbent particles. the kinetic data for ccdw presented that 43% cu 2+ was removed mainly at 180min. there was no evident change in the remaining concentration of contaminants after this time of 180 min. a. f. ali and z. t. abd ali / iraqi journal of chemical and petroleum engineering 20,1 (2019) 10 – 18 23 thus, for all equilibrium adsorption studies, the equilibration period was kept 180 min. ccdw generally contains alkali and alkaline earth metals such as ca 2+ , mg 2+ , k 2+ and na 2+ which are primarily presented from fresh water, so that, when ccdw reacts with heavy metals bearing solution, the light metals released causing an increase in the ph of the solution due to the form of light metal alkalis, as illustrated in fig. 1. fig. 1. removal efficiency as a function of shaking time and final ph of copper ion onto ccdw b. effect of initial concentration of contaminant fig. 2 presents that when the initial concentration increases from 100 to 750 mg/l the removal efficiency decreases from (56 to 13%) for cu 2+ by keeping all other parameters constant. the results present that there was a higher removal percent of the metal at the lower value of initial concentration. it may be because, at higher concentration of metal ion, the effective sites obtainable on the ccdw to interact with the contaminant approaches saturation, resulting in a decrease in overall percent removal ‎[18]. the simple hydrolysis of generality divalent metal ions particularly cu 2+ can be written as follows: m 2+ + h2o ⇌ m (oh)+ + h+ (10) where m 2+ is either cu2+ or any other metal ion the final ph increase when the concentration of the solution decreases this happens when m 2+ (metal ions) is being taken up by the adsorbent, the reaction above shifts to the left, leading to the depletion of protons and hence a rise in ph ‎[19]. fig. 2. effect of initial metal concentration on removal efficiency of copper ion onto ccdw c. shaking speed the effect of agitation speed on removal efficiency of cu 2+ on ccdw was studied varying the speed of agitation from 50 to 250 rpm, fig. 3 presents that approximately 13% of the cu 2+ was removed prior to shaking (shaking speed = 0) with conservation rest parameters equal to best ones acquired at the former steps. there is a gradual increase in the efficiency of removal of copper ion when shaking speed was increased from 0 to 250 rpm at which about 58% of cu 2+ has been removed. these results can be associated to the fact that the increase of the agitation speed, improves the spread of pollutant across the surface of the reactive material and this means more contact between the pollutant in the solution and the active sites ‎[20]. fig. 3. effect of agitation speed on percentage removal of copper ion onto ccdw d. ccdw dosage the dependence of cu 2+ sorption on ccdw dosage was studied by varying the amount of sorbent within the ranges added to 100 ml of contaminated solution with conservation rest parameters constant as illustrated in fig. 4. a. f. ali and z. t. abd ali / iraqi journal of chemical and petroleum engineering 20,1 (2019) 10 – 18 24 this figure explains the greater availability of effective sites increases the removal efficiency as increasing the amount of dosage and this has been expected as a result of the high dosage amount of sorbent in the solution. in addition, this supposed that after a certain dosage amount of sorbent, the greatest sorption sets in and hence the amount of cu 2+ attached to the substance and the remaining amount of this contaminant in solution remain consistent even with the further increase with dosage amount of sorbent ‎[20]. the best values of dosage were found to be 0.7 g ccdw/100ml for cu 2+ . increases in ph are because of the presence of carbonate content (hco3) in sorbent material, which gives buffer capacity (alkaline condition) to the sample and this was increased due to increase the dosage amount of sorbent. adding sorbent particles to an acidic aqueous solution, they will dissolve equalizing acids and will increase the concentration of dissolved calcium ‎[22]. fig. 4. effect of ccdw dosage on removal efficiencies copper ion 4.3. precipitated and bounded to ccdw of heavy metals through the course of the study, a small amount of loose floc was observed to have deposited in the nearness of the ccdw particles. for this reason, the word „removal‟ has been more suitable than „sorption‟ or „uptake‟ in this instance. the uptake of cu 2+ by attaching (bounded) to ccdw was specified by nitric acid digestion according to (chaney/mielke method) ‎[23] of the recovered ccdw and the corresponding proportions of cu 2+ present in the loose floc deposited was then calculated by a mass balance for the metal ion as follows: precipitate = initial (bound to ccdw+ remain in solution) (11) the final partitioning of the metal ion among that bounded to ccdw, precipitated, and that which remained in solution is depicted in fig. 5. fig. 5. the final partition of copper ion after 180min 4.4. isotherm models four isotherm models are used to simulate the performance of ccdw in removing heavy metal ion from contaminated wastewater. these models have been applied separately as mathematical (fitting) equations for pure sorption data (bounded to ccdw) and pure precipitation data (precipitated at the bottom of the flask), and then find the most consistent model which describes the two simultaneous processes (present model). accordingly, the constants with the coefficient of determination for each model were determined by using nonlinear regression method in the microsoft excel (2007) ‎[24]. it's summarized in table 1. table 1. isotherm models constants with a coefficient of determination for removal of cu 2+ onto ccdw model parameter cu 2+ bounded precipitated langmuir qm (mg/g) 39.286 1.895 b (l/mg) 0.078 448760.4 r 2 0.914 0.537 freundlich kf 5.410 5.5820 1/n 0.438 0.55433 r 2 0.880 0.614 redlichpeterson kr 3.050 1.995 ar 0.076 0.019 br 1.005 2.598 r 2 0.860 0.712 radkeprausnitze 39.687 107.443 3.057 1.987 1.002 2.608 r 2 0.874 0.850 it is clear from table (1 and 2) that there is a low matching between experimental (bounded & precipitated) and theoretical (isotherm models) data compared with present model, and this may be due to a high heterogeneity of ccdw material ‎[25]. however, langmuir isotherm models have the highest value of r 2 in case of pure adsorption and radkeprausnitze has the highest value of r 2 in case of pure precipitation. a. f. ali and z. t. abd ali / iraqi journal of chemical and petroleum engineering 20,1 (2019) 10 – 18 25 accordingly, the langmuir model can be used to represent the bounded and radke-prausnitze can be used to represent the precipitated portions for cu 2+ as illustrated in table 2. table 2. present model constants with the coefficient of determination for removal of cu 2+ onto ccdw contaminant present model parameters cu 2+ qm )b (mg/g) 0.594 b )b (l/mg) 107.720 qmrp )p 19.809 krp )p 8.388 mrp)p 0.859 r 2 0.998 5scanning electron microscopy (sem) secondary electron images of the surfaces of ccdw samples before and after loading of heavy metal cu 2+ using scanning electron microscope (tescan, vega iii, czech republic) are shown in fig. 6. the littered, irregular, fractured surface of ccdw before loading is depicted in figure 6(a,b). two distinct copper-bearing phases were observed to have formed on the surface of cu–ccdw: a copper-rich foliaceous mass and rare, copper-bearing, calcium-rich, distorted polygons (figure 6(c,d)). the data indicate that the principal mechanism of uptake of copper by ccdw was by precipitation of the foliated crystals onto the surface and that no appreciable diffusion of copper ions into the cement matrix had occurred ‎[16]. (a)ccdw (b)ccdw (c)cu-ccdw (d)cu-ccdw fig. 6. electron micrographs depicting the surfaces of (a, b) ccdw; (c, d) cu-ccdw 6conclusion  shaking time, the initial concentration of contaminant, shaking speed, and ccdw dosage were the most important factors affecting the removal process of heavy metals. the best conditions were (081min, 011 mg/l, 250 rpm, 0.7 g ccdw/100 ml), for cu 2+ maximum removal  the sem images detect that the cu 2+ removal by ccdw happens through precipitation of the foliated crystals onto the surface. the results indicate that a rough surface of solid media, high sorptive capacity is beneficial in the removal of heavy metals from water. thus, ccdw offers the possibility for cheap and effective media for remediation groundwater contamination with heavy metals using a permeable reactive barrier. sorption and precipitation as metal oxide were two of the mechanisms that contribute to the removal of metal from the solution. references [1] h. demiral, and c. güngör, “adsorption of copper(ii) from aqueous solutions on activated carbon prepared from grape bagasse,” journal of cleaner production, vol. 124, pp. 103-113, feb. 2016. [2] x. hung, m. sillianpaa, b. duo, e. t. gjessing, “water quality in the tibetan plateau: metal contents of four selected rivers,” journal of environmental pollution, vol. 156, no. 2, pp. 270-277, nov. 2008. [3] e. demirbas, n. dizge, m. t. sulak, m. kobya, “adsorption kinetics and equilibrium of copper from aqueous solutions using hazelnut shell activated carbon,” journal of chemical engineering, vol. 148, no. 2-3, pp. 480-487, may. 2009. https://www.sciencedirect.com/science/article/pii/s0959652616002651 https://www.sciencedirect.com/science/article/pii/s0959652616002651 https://www.sciencedirect.com/science/article/pii/s0959652616002651 https://www.sciencedirect.com/science/article/pii/s0959652616002651 https://www.sciencedirect.com/science/article/pii/s0269749108001152 https://www.sciencedirect.com/science/article/pii/s0269749108001152 https://www.sciencedirect.com/science/article/pii/s0269749108001152 https://www.sciencedirect.com/science/article/pii/s0269749108001152 https://www.sciencedirect.com/science/article/pii/s138589470800613x https://www.sciencedirect.com/science/article/pii/s138589470800613x https://www.sciencedirect.com/science/article/pii/s138589470800613x https://www.sciencedirect.com/science/article/pii/s138589470800613x https://www.sciencedirect.com/science/article/pii/s138589470800613x a. f. ali and z. t. abd ali / iraqi journal of chemical and petroleum engineering 20,1 (2019) 10 – 18 26 [4] e. eren, “removal of copper ions by modified unye clay, turkey,” journal of hazardous materials, vol. 159, no. 2-3, pp. 235-244, nov. 2008. [5] f. bouhamed, z. elouear, j. bouzid, “adsorptive removal of copper(ii) from aqueous solutions on activated carbon prepared from tunisian date stones: equilibrium, kinetics and thermodynamics,” journal of the taiwan institute of chemical engineers, vol. 43, no. 5, pp. 741-749, sep. 2012. [6] m. a. grace, e. clifford, m. g. haely, “the potential for the use of waste products from a variety of sectors in water treatment processes,” journal of cleaner production, vol. 137, no. 20, pp. 788-802, nov. 2016. [7] w. e. razzell, “chemical fixation, solidification of hazardous waste,”journal of waste management & research, vol. 8, no. 2, pp. 105-111, apr. 1990. [8] f. p. glasser, “fundamental aspects of cement solidification and stabilization,” journal of hazardous materisl,vol. 52, no. 2-3, pp. 151-170, apr. 1997. [9] a. townshend, e. jackwerth,” precipitation of major constituents for trace preconcentration: potential and problems, the scientific journal of iupac, vol. 61, no. 9, jan. 2009. [10] c. zhu, s. martin, r. ford, n. nuhfer, “experimental and modeling studies of coprecipitation as an attenuation mechanism for radionuclides, metals, and metalloid mobility,” apr. 2003. [11] m. h. el-awady, t. m. sami, “removal of heavy metals by cement kiln dust,” bulletin of environmental contamination and toxicology, vol. 59, no. 4, pp, 603-610, oct. 1997. [12] o. hamdaoui, e. naffrechoux, “modeling of adsorption isotherms of phenol and chlorophenols onto granular activated carbon: part i. two-parameter models and equations allowing determination of thermodynamic parameters,” journal of hazardous material, vol. 147, no. 1-2, pp. 381-394. aug. 2007. [13] k.y. foo, b. h. hameed, “insights into the modeling of adsorption isotherm systems,” chemical engineering journal, vol. 156, no. 1, pp. 2-10, jan. 2010. [14] b. subramanyam, d. ashutosh, “adsorption isotherm modeling of phenol onto natural soils – applicability of various isotherm models,” international journal of environmental research, vol. 6, no, 1, pp. 265-276, win. 2012. [15] s. shrivastava, “medical device materials: proceedings from the materials and processes for medical devices conference anaheim, california,” asm international, sep. 2003. [16] n. j. coleman, w. e. lee, and i. j. slipper, “interactions of aqueous cu2+, zn2+ and pb2+ ions with crushed concrete fines,” journal of hazardous materials, vol. 12, no. 1-3, pp. 203-213, feb. 2005. [17] b. yasemine, t. zeki, “removal of heavy metals from aqueous solution by sawdust adsorption,” journal of environmental sciences, vol. 19, no. 2, pp. 160-166, sep. 2007. [18] s. kagne, s. jagtap, p. dhawade, s. p. kamble, s. devotta, s. s. rayalu, “hydrated cement: a promising adsorbent for the removal of fluoride from aqueous solution,” journal of hazardous materials, vol. 154, no. 1-3, pp. 88-95, sep. 2008. [19] b. o. opeolu, o. bamgbose, o. s. fatoki, “zinc abatement from simulated and industrial wastewaters using sugarcane biomass,” water sa, vol. 37, no. 3, pp. 313-320, aug. 2011. [20] j. anwar, u. shafique, w. u. zaman, m. salamn, a. dar, s. anwar, “removal of pb(ii) and cd(ii) from water by adsorption on peels of banana,” journal of bioresource technology, vol. 101. no. 6, pp. 1752-1755, mar. 2010, [21] b.m.w.p.k.amarasinghe, r. a. williams, “tea waste as a low cost adsorbent for the removal of cu and pb from wastewater," journal of chemical engineering, vol. 132, no. 1-3, pp. 299-309, aug. 2007. [22] h. a. aziz, m. n. adlan, k. s. ariffin, “heavy metals (cd, pb, zn, ni, cu and cr (iii)) removal from water in malaysia: post treatment by high quality limestone,” journal of bioresource technology, vol. 99, no. 6, pp. 1578-1583, apr. 2008. [23] ray. w. brown, c. gonzales, m. j. hooper, a. c. bayat, a. m. fornerette, t. j. mcbride, t. longoria, h. w. mielke, “soil lead (pb) in residential transects through lubbock, texas: a preliminary assessment,” journal of environmental geochemistry and health, vol. 30, no. 6, pp. 541-547, dec. 2008. [24] a. m. brown, “a step-by-step guide to nonlinear regression analysis of experimental data using a microsoft excel spreadsheet,” journal of computer methods and programs in biomedicine, vol. 65, no. 3, pp. 191-200, jun. 2001. [25] f. colangelo, r. cioffi, “use of cement kiln dust, blast furnace slag and marble sludge in the manufacture of sustainable artificial aggregates by means of cold bonding pelletization,” journal of materials science, vol. 6, no. 8, pp.3139-3159. jul. 2013. https://www.sciencedirect.com/science/article/pii/s0304389408002409 https://www.sciencedirect.com/science/article/pii/s0304389408002409 https://www.sciencedirect.com/science/article/pii/s0304389408002409 https://www.sciencedirect.com/science/article/pii/s1876107012000387 https://www.sciencedirect.com/science/article/pii/s1876107012000387 https://www.sciencedirect.com/science/article/pii/s1876107012000387 https://www.sciencedirect.com/science/article/pii/s1876107012000387 https://www.sciencedirect.com/science/article/pii/s1876107012000387 https://www.sciencedirect.com/science/article/pii/s1876107012000387 https://www.sciencedirect.com/science/article/pii/s0959652616310095 https://www.sciencedirect.com/science/article/pii/s0959652616310095 https://www.sciencedirect.com/science/article/pii/s0959652616310095 https://www.sciencedirect.com/science/article/pii/s0959652616310095 https://www.sciencedirect.com/science/article/pii/0734242x9090030q https://www.sciencedirect.com/science/article/pii/0734242x9090030q https://www.sciencedirect.com/science/article/pii/0734242x9090030q https://www.sciencedirect.com/science/article/pii/0734242x9090030q https://www.sciencedirect.com/science/article/pii/s0304389496018055 https://www.sciencedirect.com/science/article/pii/s0304389496018055 https://www.sciencedirect.com/science/article/pii/s0304389496018055 https://www.degruyter.com/view/j/pac.1989.61.issue-9/pac198961091643/pac198961091643.xml https://www.degruyter.com/view/j/pac.1989.61.issue-9/pac198961091643/pac198961091643.xml https://www.degruyter.com/view/j/pac.1989.61.issue-9/pac198961091643/pac198961091643.xml https://www.degruyter.com/view/j/pac.1989.61.issue-9/pac198961091643/pac198961091643.xml http://adsabs.harvard.edu/abs/2003eaeja.....6552z http://adsabs.harvard.edu/abs/2003eaeja.....6552z http://adsabs.harvard.edu/abs/2003eaeja.....6552z http://adsabs.harvard.edu/abs/2003eaeja.....6552z https://link.springer.com/article/10.1007%2fs001289900522?li=true https://link.springer.com/article/10.1007%2fs001289900522?li=true https://link.springer.com/article/10.1007%2fs001289900522?li=true https://link.springer.com/article/10.1007%2fs001289900522?li=true https://www.sciencedirect.com/science/article/pii/s0304389407000568 https://www.sciencedirect.com/science/article/pii/s0304389407000568 https://www.sciencedirect.com/science/article/pii/s0304389407000568 https://www.sciencedirect.com/science/article/pii/s0304389407000568 https://www.sciencedirect.com/science/article/pii/s0304389407000568 https://www.sciencedirect.com/science/article/pii/s0304389407000568 https://www.sciencedirect.com/science/article/pii/s1385894709006147 https://www.sciencedirect.com/science/article/pii/s1385894709006147 https://www.sciencedirect.com/science/article/pii/s1385894709006147 https://www.sciencedirect.com/science/article/pii/s1385894709006147 https://ijer.ut.ac.ir/article_492_0.html https://ijer.ut.ac.ir/article_492_0.html https://ijer.ut.ac.ir/article_492_0.html https://ijer.ut.ac.ir/article_492_0.html https://ijer.ut.ac.ir/article_492_0.html 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https://link.springer.com/article/10.1007/s10653-008-9180-y https://link.springer.com/article/10.1007/s10653-008-9180-y https://link.springer.com/article/10.1007/s10653-008-9180-y https://link.springer.com/article/10.1007/s10653-008-9180-y https://link.springer.com/article/10.1007/s10653-008-9180-y https://www.sciencedirect.com/science/article/pii/s0169260700001243 https://www.sciencedirect.com/science/article/pii/s0169260700001243 https://www.sciencedirect.com/science/article/pii/s0169260700001243 https://www.sciencedirect.com/science/article/pii/s0169260700001243 https://www.sciencedirect.com/science/article/pii/s0169260700001243 https://www.mdpi.com/1996-1944/6/8/3139 https://www.mdpi.com/1996-1944/6/8/3139 https://www.mdpi.com/1996-1944/6/8/3139 https://www.mdpi.com/1996-1944/6/8/3139 https://www.mdpi.com/1996-1944/6/8/3139 https://www.mdpi.com/1996-1944/6/8/3139 a. f. ali and z. t. abd ali / iraqi journal of chemical and petroleum engineering 20,1 (2019) 10 – 18 27 تفاعل محلول أيونات النحاس مع حبيبات الخرسانة المسحوقة الخالصة تم دراسة ازالة أيونات النحاس من المياه العادمة االصطناعية باستخدام نفايات ىدم الخرسانة المسحوقة (ccdw التي تم جمعيا من موقع اليدم في نظام الدفعات. تم دراسة ) العوامل التي تؤثر عمى كفاءة االزالة تم استخدام أربعة لوصف بيانات اإلزالة مثل زمن الرج، تركيز االبتدائي، سرعة الرج، الجرعات الممتزة. (. أكدت prausnitz-radkeو peterson-redlichو freundlichو langmuir) isothermنماذج 0.7دورة بالدقيقة و 051لتر و/ممغم 011دقيقة و 081انت )تجارب الدفعات أن أفضل القيم ليذه العوامل ك أثبتت النتائج ان عممية االمتزاز و .%011مل( عمى التوالي حيث بمغت كفاءة اإلزالة المتحققة 011/غم الترسيب النقي ىم االلية الرئيسية إلازالة أيونات الرصاص من المحاليل المائية ويمكن تمثيل بيانات اإلزالة خالل تم أزالة أيونات النحاس بنجاح من المحاليل المائية prausnitz-.radkeو langmuirاسطة موديلبو ممم تم دراسة ازالة 0إلى 0( في نطاق حجم الجسيمات يتراوح من ccdwدراسة تجارب الدفعات باستخدام ) ( التي تم ccdwلمسحوقة )أيون النحاس من المياه العادمة االصطناعية باستخدام نفايات ىدم الخرسانة ا جمعيا من موقع اليدم في نظام الدفعات. كشف المسح المجيري اإللكتروني أن اآللية الرئيسية إلزالة النحاس نشأت من تفاعالت ترسيب السطح. خط التحاور ,أيون معدن ثقيل ,نفايات ىدم الخرسانة ,إعادة التدوير, إلزالةا: ولدالالكممات ا available online at https://ijcpe.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.19 no.1 (march 2018) 29 – 43 issn: 1997-4884 corresponding authors: basma abbas abdel majeed, email: basma1957@yahoo.com, raheem jameel muhseen, email: raheemjamail@yahoo.com, nawras jameel jassim, email: nawras.jassim@gmail.com iraqi journal of chemical and petroleum engineering adsorption of diclofenac sodium and ibuprofen by bentonite polyureaformaldehyde thermodynamics and kinetics study basma abbas abdel majeed a , raheem jameel muhseen b and nawras jameel jassim c a college of engineering -university of baghdad b college of pharmacy-university of basra c basra technical institute -southern technical university abstract an increasing number of emerging contaminants have been detected in surface waters, sediment, soil and ground water in different locations in the world, which is a new environmental challenges need an actual concern for international scientific and legislative communities. the nonprescription and huge used pharmaceuticals ibuprofen and diclofenac sodium will be focused in this study. new adsorbent developed using cheap inorganic clay material (bentonite) and organic polymer polyureaformaldehyde (puf), the combination of these two materials gave the surface more roughness with wide active site distribution. batch adsorption experiment performed to each pharmaceutical individually to determine the optimum separation parameters and understanding the adsorption process pathway. both pharmaceuticals adsorbed on bentonite –puf adsorbent in short time ranges from 15 min for ibuprofen to 30 min for diclofenac sodium .thermodynamic analysis indicates the adsorption process is endothermic in nature and fall in the region of physical adsorption for tested pharmaceuticals (δh˚= 14.69 kj/mol for both ibuprofen and diclofenac sodium 23.33 and respectively).elovichs equation for describing kinetics of adsorption seemed a good fit with adsorption of both pharmaceuticals .the effect of ph had a significant effect for both pharmaceuticals with high removal (99.8% for diclofenac and 99.2 % for ibuprofen) at acidic ph=2 below pka value. isotherm studied at different initial concentration, the results showed that the dubinin-radushkevich model suitable for describing ibuprofen adsorption, and freundlich's isotherm for diclofenac sodium. keywords: emerging contaminants, (bentonite), polyureaformaldehyde (puf) 1introduction a global interest on development active separation technology for emerging contaminants ecs removal from water, filtration with coagulation, precipitation, ozonation,photolysis, membrane bioreactor (mbr) , advance oxidation, ion exchange and reverse osmosis. these methods are restricted and consume high operation and capital costs. or in some cases don‟t rid of contaminants permanently [1]. the most efficient separation process used in wastewater treatment is adsorption ,due to low cost , low investment and simple design and operation. ibuprofen is nonsteroidal anti-inflammatory drugs nsaids act by inhabit hormones that cause pain in the body cylooxygenase-2 (cox-2).ibuprofen is the dominated non-prescription pharmaceutical used worldwide. diclofenac is nsaid , this medicine works by reducing substances in the body that cause pain and inflammation used to treat mild to moderate pain, or signs table (1) clarified some physiochemical properties of interested pharmaceuticals. several researches focused on removal of diclofenac sodium and ibuprofen, adsorption of ibuprofen and diclofenac sodium using mesoporous silica confirmed at ph range from 3-5 and 15 minutes contact time [2]. interaction of indomethacin and diclofenac solutions, on multi-walled carbon nanotube mwcnt adsorbent reported high adsorption capacity value for diclofenac sodium than indomethacin in mwcnt surface [3]. adsorption of diclofenac on functionalized silica-based material [4], clay and activated carbon [5]. ibuprofen adsorption on bentonite surface in the presence of surfactant, authors concluded that the presence of surfactant enhance adsorption capacity and don‟t affect the equilibrium time [6]. different adsorbent materials activated carbon cloths [7],activated carbon [8],activated biochar [9] and cyclamer persicum tubers activated carbon [10] used in literature for adsorption of ibuprofen or diclofenac. 2experimental work 2.1. materials & method oren hydrocarbons middle east ltd commercial bentonite were used in this study, the chemicals used in this research clarified in table (2). a.a. majeed, et al./ iraqi journal of chemical and petroleum engineering11,1 (2018) 29-43 03 all reagents and solvent used during this work were reagent grade and used without further purification. 2.2. preparation urea formaldehyde –bentonite composite bentonite washed in ultrapure deionized water for three times and then drying in oven at 100 ˚c for two hours .different masses ratios of bentonite to poly urea formaldehyde 1:1,2:1,3:1,4:1 and 5:1 g/g and took to prepare composite of puf –bentonite.the composite mixed vigorously at temperature 60˚c for 15 minutes , then put composite in an oven at 110 ˚c for 24 hour for solidification .the composite washed many times with ultrapure deionized water finally dried in an oven to remove moisture at 100 ˚c. the sample was crushed and screened through a 200-mesh for further use in batch experiments. 2.3. adsorption experiments protocols the adsorption studies were conducted with 0.050 g of 200 mesh adsorbent and 20 ml of single pharmaceutical solution at desired concentration, ph and temperature on a constant speed of 180rpm. the solution was filter in 0.1 microns filter syringe and the concentration of pharmaceuticals in the supernatants was examined with a spectrophotometer at the wavelength of each pharmaceutical at which the maximum absorbency occurred. then the amounts of pharmaceuticals adsorbed per unit mass of adsorbent and removal efficiency of adsorbent were calculated from the following equations: (1) (2) where q is the adsorption capacity mg/g at any time t, ci and ce is initial and equilibrium concentration respectively in mg/l, v (l), the volume of solution used in adsorption experiment, m(g), the mass of the adsorbent used. different experiment will be conducted in batch form using adsorbent (bentonite-puf) and fixed 180 r.p.m, such as checking different mass ratio of bentonite to puf(bentonite only to 5:1 g/g), effect of ph(from 1.5 to 13), and interaction between temperature and contact time(temperature range from 10 ˚c to 77˚c).thermodynamic parameters will be determine using a conventional thermodynamic equations. adsorption kinetic will be tested using four three type of kinetic equations .adsorption isotherm tested using four isotherm models. 2.4. calibration and method validation uv spectrophotometer were used to quantification of pharmaceuticals concentration , maximum wave length tested from 200-400 nm .the maximum wave length tested ,for ibuprofen is 222nm and agreed with joshi [11] and diclofenac sodium at 276 nm and agreed with khaskheli and khan [12]&[13]. stock solution of each pharmaceuticals prepared in concentration range from 0 to 100 µg/ml to draw the concentration against absorbance to further use in concentration quantification experiment. the calibration curves illustrated in fig. 1&2 fig. 1, standard curve for ibuprofen in .01m nacl solution in .01m nacl solution fig. 2, standard curve for diclofenac sodium in .01m nacl solution in 0.01m nacl solution a.a. majeed, et al./ iraqi journal of chemical and petroleum engineering11,1 (2018) 29-43 03 table 1. physical, chemical and properties of ibuprofen & diclofenac sodium item description /value ibuprofen description /value diclofenac sodium structure formula c13h18o2 c14h10cl2nnao2 iupac name 2-[4-(2-methylpropyl)phenyl]propanoic acid sodium;2-[2-(2,6-dichloroanilino)phenyl]acetate molecular weight 206.28 g/mol 318.14 (g/mol) pka 5.2 4 log kow 3.97 4.51 melting point 75-77.5 283-285 °c table 2. chemical used in experiment material manufacture formaldehyde solution 37% merck urea powder (mw=60.06) romil hydrochloric acid 37% scharlau sodium hydroxide pellets analytical rasayan deionized water with conductivity less than 0.07µs/cm al-najebia gas station from edi effluent /basra diclofenac sodium sigma life science 3characterization and testing 3.1. ftir spectroscopy ftir spectra of the bentonite-puf samples after and before adsorption of single and all pharmaceuticals and bentonite only using shimadzu spectrophotometer. the ftir spectrum of the sample obtained by method including kbr pellet .mixture of sample to kbr ratio of 1:50 will be used .ftir spectra were recorded in the region of 4000-400 cm −1 3.2. scanning electron microscopy scanning electron micrograph and surface morphology of the sample was obtained by using (inspect 550) microscope was normally performed at 10 kv. 3.3. xrd analysis powder xrd analysis of both bentonite and bentonitepuf was obtained using samples was performed on the (pan alytical); a copper (cu) anode was used in the x-ray tube and operated at current 20ma and 40 kv. 4error analysis the use r 2 is limited to describe the fitting to linear behavior, and doesn‟t describe the nonlinear behavior. in this study used chi-square test (χ 2 ) ,root mean square error (rmse) and average relative error (are) .below the formulas to calculate each error function[14];[15];[16]&[17] : ∑ (3) √∑ (4) ∑ | | (5) fig. 3, effect of composite mass ratios on ibuprofen and diclofenac sodium adsorption, parameters conditions ,ph=7,contact time 3h ,adsorbent mass 0.05g ,sample volume 20 ml, mixing speed 180 r.p.m and initial concentration 40 µg/ml 5results and discussion 5.1. effect of bentonite to puf mass ratio the adsorption of diclofenac sodium and ibuprofen by composite adsorbents with different mass ratios of bentonite and puf shown in fig.3. it observed that the adsorption capacity increase by increasing bentonite content until reaching the best ratio of 3:1(3g bentonite/1g puf) then the increasing of bentonite reduce the adsorption capacity. this may attributed to increase organic /inorganic interaction between puf and bentonite which responsible to convert the surface from hydrophilic to organophilic by urea groups. a.a. majeed, et al./ iraqi journal of chemical and petroleum engineering11,1 (2018) 29-43 03 increasing puf in composite compare with bentonite weight caused also decrease in adsorption capacity because surface became more amorphous and reduce crystalline structure .this confirmed by previous investigator focused on mixing organic group with clay[18]&[19]. the best composite ratio bentonite to puf will be used for further experiments is 3:1 for bentonite to puf ratio. 5.2. interaction between equilibrium time & temperature except for high adsorption capacity, fast adsorption rate is also indispensable for practical application. from the other hand heat stress had a significant effect on adsorption behavior. regarding the temperature effect variable temperatures will help in evaluating the basic thermodynamical functions (δh˚, δg˚, δs˚) of the adsorption process. sometimes temperature gave indicator about whether the adsorption is chemical or physical in nature .adsorption of selected pharmaceuticals at different contact times were studied as a function of temperature difference in single compound phase .keeping all other parameters constant using neutral ph and 40 µ/ml initial concentration for each pharmaceuticals except ,mixing speed of 180 r.p.m and bentonite –puf composite mass about 0.05g in 20 ml of individual pharmaceutical solution. batch adsorption experiments were conducted with bentonite –puf composite by varying string times from 0 to 60 min and temperature changing from 10 to 77˚c.the results for both adsorption removal and capacity are presented in fig.(4 &5).ibuprofen attained equilibrium at very short time 15 min with maximum removal of 81.5% at temperature 47˚c and 13.3mg maximum capacity. percentage removal of 78.4%, and 12.6 mg/g capacity for diclofenac in equilibrium time of 30 min and 47˚c. the contact equilibrium time achieved in this study is shorter than the contact time using different adsorbent in many researches focused on selected nsaids [20];[21] ;[22] &[10]. as emerging contaminants (ecs), the time graphs for all pharmaceuticals indicates a quick initial adsorption rate at the first 15 min and then slowly increased until reach equilibrium, the adsorption rate became practically constant. the adsorption capacity alteration at the early minutes was observed, this may be attributed to high driving force and large number of empty active site available on bentonite–puf surface. further increase in contact time did not show significant change in adsorption capacity; that is, the adsorption phase reached equilibrium and limited active sites and reduction the concentration gradient (driving force) .the remaining active site still vacant even with achieving equilibrium then trying with other parameters to shift the driving force to enhanced capacity are required . the overlap between temperature and contact equilibrium time showed increasing adsorption removal and capacity with increasing temperature until reach temperature of 47˚ c ,then any further increasing in temperature lead to decrease adsorption capacity. the enhancement in adsorption capacity with rising in temperature may be attributed to increases the rate of diffusion of the adsorbate pharmaceuticals molecules across the boundary layer and within the internal pores of the adsorbent particle, due to decrease in the viscosity of the solution. at high temperature water structuring around hydrophobic part of pharmaceuticals decreased the adsorbate molecule become more free to diffusion and increased diffusion rate,[23] & [24]. álvarez concluded increasing adsorption capacity with increasing temperature for diclofenac adsorption on carbon xerogels [25]. fig. 4, interaction between temperature and contact time on adsorption capacity of ibuprofen initial concentration of 40 µg/ml ,ph=7and 0.05 g adsorbent weight fig. 5, interaction between temperature and contact time on adsorption capacity of diclofenac sodium initial concentration of 40 µg/ml ,ph=7and 0.05 g adsorbent weight a.a. majeed, et al./ iraqi journal of chemical and petroleum engineering11,1 (2018) 29-43 00 5.3. thermodynamic aspects the thermodynamics parameters, which characterize the equilibrium of the pharmaceuticals adsorption system such as gibbs free energy change ∆g˚,the entropy change ∆s˚ and the enthalpy change ∆h˚ will be determined in this section .the temperature range took in this section from 10˚c to 47˚c for each ibuprofen ,indomethacin ,acetylsalicylic acid , acetaminophen ,diclofenac sodium and mefenamic acid. these parameters can be determine using the following relations [26] (6) (7) (8) where: kd : equilibrium constant ce : equilibrium concentration of adsorbate in aqueous solution ca : concentration of adsorbate in solid adsorbent (ci – ce) ∆s˚ : entropy change j/mol.˚k ∆g˚ : gibb‟s free energy change ∆h˚: enthalpy change j/mol t: absolute temperature ˚k r: universal gas constant 8.314 j/mol.˚k by drawing the linear relationship between ln kd and 1/t of eq. (6) can obtain the values of ∆h˚ and ∆s˚, ∆g˚ values were computed for each temperature by the helmholtz relation eq.'s (7) or (8).fig. (6) explain the linear plot between ln kd and 1/t , with r2 value of 0.9983 other thermodynamic parameter listed in table (3) for ibuprofen the results show a negative value of -∆g˚ for all temperature ranges and positive value for both ∆s˚&∆h˚, same results for ibuprofen adsorption investigated in previous literatures[26]; [27]&[28],opposite behavior observed [29]. fig.(7) explain the linear plot between ln kd and /t , for diclofenac sodium with r2 value of 0.9773 ,other thermodynamic parameter listed in table (4). results for diclofenac sodium agreed with carvalho &suriyanon[30] &[4], negative ∆h˚ and ∆s˚ obtained by jodeh[10],exothermic adsorption observed antunes[31]. it's evident from the figures and tables for selected pharmaceuticals that the ∆g˚ values in all temperatures ranges were negative and increase its absolute value with temperature increased. this negative values indicates the feasibility and spontaneity of ongoing adsorption process so the adsorption process of both pharmaceuticals is spontaneous in nature and were more favorable at high temperature in other words the adsorption driving force increase with temperature increased. general aspects that the ∆g˚ value in the range of 0 to 20kj/mol and -80 to 000 kj/ mol for physical and chemical adsorptions, respectively[32]. the ∆g˚ values for this study pharmaceuticals ranging from (-0.002 to 3.4 kj/mol) this findings refers to the physical nature of adsorption of ibuprofen and diclofenac sodium on bentonite –puf composite. the positive value of ∆h˚ (23.33 and 14.69) kj/mol for ibuprofen and diclofenac sodium affirm that the adsorption of adsorbate pharmaceuticals on the bentonite –puf composite are an endothermic in nature .the high value of ∆h˚ for ibuprofen confirm the strong temperature depending to perform physical adsorption. the concerned process achieved equilibrium by consuming energy from the considered adsorption system [28]. the positive value of ∆s˚ shows an increase in the disorder and randomness at the surface /solution interface, accompanying with some structural changes in both adsorbate and adsorbent as a results of interaction of pharmaceuticals molecules with active sites in the bentonite–puf composite surface. the ∆s˚value for ibuprofen greater than diclofenac sodium. generally the obtained ∆s˚ results are close to the previous researchers [26] & [28]. fig. 6, determination of thermodynamic parameters (∆g˚, ∆s˚&∆h˚) for the adsorption, of ibuprofen fig. 7, determination of thermodynamic parameters (∆g˚, ∆s˚&∆h˚) for the adsorption, of diclofenac sodium a.a. majeed, et al./ iraqi journal of chemical and petroleum engineering11,1 (2018) 29-43 03 table 3. thermodynamics parameters for ibuprofen temperatur e ˚c kd ∆g˚ kj/mol ∆h˚ kj/mol ∆s˚ kj/mol.˚k 10 1.188 -0.405 23.33 0.08 27 2.015 -1.74 37 2.859 -2.70 47 3.696 -3.47 table 4. thermodynamics parameters for diclofenac sodium temperatur e ˚c kd ∆g˚ kj/mol ∆h˚ kj/mol ∆s˚ kj/mol.˚k 10 1. -0.002 14.6925 0.051859 27 1.382 -0.807 37 1.677 -1.33 47 2.099 -1.973 5.4. determination of rate parameters determination the efficiency of adsorption processes requires a brief an understanding of kinetics of pharmaceuticals uptakes by bentonite –puf composite, and the time influence on concentration distribution of adsorbate in both solid adsorbent surface and liquid solution. also determination the rate controlling step during the adsorption process important to know.the adsorption kinetic of ibuprofen and diclofenac sodium were modeled using pseudo first order, pseudo second order, elovich‟s equation and intraparticle modules. pseudo first order rate equation is expressed as follows [33]: (9) where : adsorption capacity at time t (mg/g) : adsorption capacity at equilibrium(mg/g) : pseudo first order rate constant (min. -1 ) after integration and applying boundary conditions t=0 and qt=0 to t = t and qt=qe at equilibrium, the above equation becomes: (10) the pseudo second order mode is given by the following [33]: (11) where: k2: pseudo second order rate constant. for the same boundary conditions, the integrated form of equation (11) becomes: (12) the elovich's equation is generally expressed as follows [26] : (13) where: is the initial adsorption rate (mg/g) and is adsorption constant (mg/g.min). the intraparticle diffusion model is formulated by [26]: (14) where: kp intraparticle diffusion rate constant (mg/g.min 0.5 ) the kinetic experiments conducted at different temperature ranges and all results applied to the linear kinetics models in above equations to calculate rate constant parameters. different statistical functions used r 2 ,χ 2 ,are and rmse to describe the best fit model . the kinetic experiment of ibuprofen conducted with time intervals from 5 to 30 min with initial solution concentration of 40 µg/ml and ph adjusted to 7.the linear plot of applying different models at different temperatures constants values and error function listed in table (5). it's clear from the table that the best fit model for ibuprofen is elovichs equation and second order kinetics due to minimum error function value observed at 10 ˚c. this comparison cleared in fig.(8) between (qt) calculated from the kinetic models and the experimental values.the adsorption initial rate of ibuprofen on to bentonite-puf composite (α) increased with temperature increased. the value of 1/β, indicative of the number of sites available for adsorption, was found higher value of 5 g.min./mg at temperature 47˚c and decreased as temperature decreased to value of 3.4 g.min./mg at temperature10˚c .from the other hand the values of second order rate constant increase with temperature increased as in table (5). fig. 8, comparison between experimental and different kinetics models for ibuprofen at temperature 10˚c a.a. majeed, et al./ iraqi journal of chemical and petroleum engineering11,1 (2018) 29-43 03 any way the first order kinetics model and intraparticle diffusion model were not in good agreement to describe the experimental kinetics of ibuprofen. these results are agreed with previous work [26] ; [29] ; [34]&[28] . fig. 9, comparison between experimental and different kinetics models of diclofenac sodium at temperature 47˚c the calculated parameters for bentonite-puf adsorbent , four kinetics models, and the respective error functions for the data and model, are summarized in table (6) for diclofenac sodium .from the review the value of error correlations coefficients, the adsorption of diclofenac sodium on to bentonite-puf adsorbent is closely performed by elovichs equation kinetics although agreeable, but not perfect fit with pseudo-second rate model fig.(9).intraparticle diffusion coefficient appear with high values and limited error and increase with temperature increased this indicates the adsorption of diclofenac sodium at low temperature required a higher amount of bentonite –puf than at high temperature to reach the same adsorption efficiency. the number of site available 1/β increased with temperature from the value 3.5 to 5 g.min./mg. the adsorption initial rate of diclofenac sodium α increase with temperature increased. for all studied nsaids , the adsorption plots of intraparticle diffusion model did not pass through the origin and the external mass transfer played an important role in the nsaids adsorption [4]. it was observed that intra-particle rate constant values increased with temperature for both pharmaceuticals . this may attribute promoting large number of pharmaceutical molecules to diffuse to pore before being adsorbed. table 5. values of kinetic constants and error functions for ibuprofen first order t (c˚) r 2 χ 2 rmse are qe exp. qe model. k1 47.00 0.28 8.88 4.67 0.37 13.40 7.65 0.15 37.00 0.32 8.38 4.40 0.37 12.60 7.30 0.14 27.00 0.29 7.50 3.96 0.37 11.38 6.52 0.14 10.00 0.39 6.12 3.20 0.38 9.27 5.50 0.12 second order t (c˚) r 2 χ 2 rmse are qe exp qe model. k2 47.00 0.87 38.33 7.13 0.88 13.40 18.80 0.05 37.00 0.87 0.80 1.19 0.13 12.60 17.70 0.005 27.00 0.87 0.70 1.07 0.13 11.38 15.97 0.006 10.00 0.87 0.56 0.86 0.13 9.27 12.89 0.007 elovich t (c˚) r 2 χ 2 rmse are qe β α 47 0.8534 0.757126 1.254 0.1174 13.4 0.202 3.057685 37 0.8525 0.726908 1.183 0.12 12.6 0.21 2.885768 27 0.8535 0.641559 1.064 0.1171 11.38 0.23 2.596596 10 0.8536 0.513099 0.859 0.1159 9.27 0.295622 2.128285 intraparticle t (c˚) r 2 χ 2 rmse are qe kp c 47 0.7474 1.511686 1.646 0.1731 13.4 2.56 0.6421 37 0.7452 1.452947 1.555 0.1759 12.6 2.4047 0.6298 27 0.7476 1.280814 1.397 0.1728 11.38 2.1737 0.5453 10 0.7478 1.023028 1.127 0.171 9.27 1.7557 0.4901 a.a. majeed, et al./ iraqi journal of chemical and petroleum engineering11,1 (2018) 29-43 03 table 6. values of kinetic constants and error functions of diclofenac sodium first order t(c˚) r 2 χ 2 rmse are qe qmode k1 47.00 0.98 350.26 24.35 0.40 12.55 37.39 0.23 37.00 0.47 2.41 2.24 0.04 11.70 9.01 0.17 27.00 0.43 2.23 2.09 0.04 10.90 8.32 0.16 10.00 0.62 0.99 0.93 0.01 9.25 8.59 0.16 second order t(c˚) r 2 χ 2 rmse are qe qmode k2 47.00 0.89 0.37 0.80 0.01 12.55 20.83 0.00 37.00 0.87 0.65 1.05 0.02 11.70 17.45 0.00 27.00 0.87 0.57 0.94 0.02 10.90 16.16 0.00 10.00 0.88 0.42 0.75 0.02 9.25 13.93 0.01 elovich equation t(c˚) r 2 χ 2 rmse are qe β α 47.00 0.95 0.25 0.68 0.02 12.55 0.20 2.49 37.00 0.88 0.57 1.02 0.03 11.70 0.22 2.62 27.00 0.89 0.49 0.91 0.03 10.90 0.24 2.40 10.00 0.90 0.36 0.72 0.02 9.25 0.28 2.02 intraparticle t(c˚) r 2 χ 2 rmse are qe kp c 47.00 0.88 0.77 1.09 0.02 12.55 2.66 -0.71 37.00 0.78 1.21 1.38 0.03 11.70 2.34 0.27 27.00 0.79 1.07 1.25 0.03 10.90 2.17 0.19 10.00 0.81 0.82 1.00 0.03 9.25 1.86 0.09 5.5. effect of solution ph the effect of ph studied in the range 1.5 to 13 for ibuprofen, and diclofenac sodium. the results of ph effect on both adsorption capacity and removal efficiency are explained in fig.(10& 11) for ibuprofen and diclofenac sodium . it observed from fig.(10) that ibuprofen removal efficiency about 96% at ph value of 1.5 and dropped at ph of 13 to 51%. the adsorption removal efficiency of diclofenac sodium equal to (99.8%). the maximum capacity was observed at ph range 1.53.5 for (diclofenac sodium, and ibuprofen adsorption. the pka value of these pharmaceuticals (ibuprofen=5.2 and , diclofenac sodium = 4) which vary according to their molecular structure .at ph value below pka ionization of pharmaceutical compound will be occur ,then additional to electrostatic interaction increased in nonelectrostatic interactions occur ,including hydrogen bonding between pharmaceuticals and bentonite –puf surface by increasing the positive charges .from the other hand „van der waal‟ interaction between pharmaceuticals and the adsorbent surface increased due to decrease the solubility with increasing ph. for the same group of pharmaceuticals diclofenac sodium and ibuprofen, the removal capacity decrease with increase ph to basic media. this behavior due to the successive deprotonation of positive charged groups at ph above pka. therefore, more molecules exist in anion forms this caused electrostatic increase ph to basic media. this behavior due to the successive deprotonation of positive charged groups at ph above pka. therefore, more molecules exist in anion forms this caused electrostatic repulsion between negatively charged sites on the adsorbent and pharmaceuticals .also competition between -oh and pharmaceuticals to fill the positively charged adsorption active sites will be dominate [35]. similar path observed in literature [21];[36] & [10]. generally ph variation control the hydrophilic part in pharmaceutical molecules ,in the other words responsible for increase or decrease the interaction between active pharmaceutical molecule groups and surface groups rather than hydrophobic molecules adsorption 5.6. adsorption isotherm the successful adsorption separation process to remove pharmaceutical contaminants depends on a good description of equilibrium distribution between two phases. by plotting residual liquid phase concentration against equilibrium capacity at specified time, it can possible to describe the equilibrium adsorption isotherm. requirement of design concentration of adsorption system to eliminate pharmaceutical pollutants from contaminant water, it's important to establish the most fit correlation to describe an equilibrium curves. a.a. majeed, et al./ iraqi journal of chemical and petroleum engineering11,1 (2018) 29-43 03 there are many theories relating to adsorption equilibrium and among the used models are langmuir, freundlich, dubinin-radushkevich and temkin [37].in order to optimize the design the mathematical equations of these models are illustrated in literatures [38];[39];[40] will be used to describe the best fit data to experimental results. the selection of the best fitting model is determine by calculating three error deviation functions χ 2 ,are and rmse between experimental and predicted equilibrium data after applying linear and nonlinear form of adsorption isotherm [37]. important parameter denoted the essential characteristics of the langmuir isotherm can be expressed in terms of a dimensionless constant separation factor, rl, can be defined as follows [41] : (15) where c˳ initial pharmaceutical concentration µg/ml,kl langmuir adsorption constant (ml/µg).the adsorption process consider as favorable when 0˂ rl˂1 and linear when rl=1 , rl = 0 indicates irreversible adsorption, while an rl value greater than 1 signifies an unfavorable adsorption process [42] & [41].in addition, the freundlich adsorption intensity parameter 1/n had an indication about the adsorption difficulty .the adsorption is considered easy when 1/n<0.5 and difficult when 1/n>2 [41]. the characteristic adsorption energy eo (kj/mole) used to distinguish the physical and chemical adsorption. value of e is between 8 and 16 kj /mole indicates the adsorption is chemisorption, while for values of e 0˂ 8 kj /mole, the sorption process is physical [43] &[44]. adsorption isotherm of ibuprofen tested using concentration range from 20 to 100 µg/ml , ph of solution fixed on 2 to 2.5 ,the contact time was 15 min., temperature used was 47˚c finally used 0.05 g of bentonite-puf adsorbent. the results of application linear form of adsorption isotherms and isotherm constants and error functions listed in table (11).the comparison between experimental results and models results clearly showed in fig.(12) for ibuprofen. by comparing the isotherms applied for ibuprofen ,its seems from error functions values table (7) that the best fit isotherms sorts as dubinin-radushkevich ˃ temkin˃ langmuir˃ freundlich's.the best fit isotherm with dubinin-radushkevich isotherm which assumed that the characteristic of the adsorption curve is related to the porosity of the bentonite –puf adsorbent .the dubinin-radushkevich model is more general than freundlich and langmuir isotherms ,because it was studied the difference between physical and chemical adsorption [27]. the maximum sorption capacity calculated from this model qdr=27.6 mol/g. the magnitude of kf calculated from freundlich isotherm showed that bentonite-puf adsorbent had a high capacity for ibuprofen adsorption from the aqueous solutions studied. the freundlich adsorption intensity parameter 1/n had a value of 0.13 indicate the adsorption process of ibuprofen on bentonite –puf surface is easy. the separation factor, rl calculated from langmuir isotherm showed the values ˂1 and greater than zero in all adsorption concentrations which suggest that the adsorption process of ibuprofen on bentonite –puf surface is favorable. the characteristic adsorption energy eo calculated from dubinin-radushkevich isotherm for ibuprofen equal to 0.845 kj/mol this another confirmation that the adsorption process physical in nature of ibuprofen on bentonite –puf surface rather than thermodynamic parameters calculated previously. approximated issues in previous studies for ibuprofen adsorption using different adsorbent [45];[36] & [27]. adsorption isotherm of diclofenac sodium conducted using concentration range from 20 to 100 µg/ml, ph of solution fixed on 2 to 2.5, the contact time was 30 min., and temperature used was 47˚c finally used 0.05 g of bentonite-puf adsorbent. the results of application linear form of adsorption isotherms and the isotherm constants and error functions listed in table (8). the comparison between experimental results and models results clearly showed in fig.(13). by comparing the isotherms applied for diclofenac sodium ,its seems from error functions values table (8) that the best fit isotherms sorts as freundlich's˃ ˃ langmuir˃ temkin˃ dubinin-radushkevich.the best fit isotherm with freundlich's isotherm shows that capacity will increase with diclofenac sodium concentration increased .the main assumption regarding freundlich model that the adsorption of diclofenac sodium occurred in a multilayered system rather one layered on the bentonite – puf surface [2]. the magnitude of kf calculated from freundlich isotherm showed that bentonite-puf adsorbent had a high capacity for diclofenac sodium adsorption from the aqueous solutions and its value above value calculated for ibuprofen, acetylsalicylic acid, acetaminophen and indomethacin. the freundlich adsorption intensity parameter 1/n had a value of 0.33 indicate the adsorption process of diclofenac sodium on bentonite –puf surface is in the favorable and easy region .the separation factor, rl calculated from langmuir isotherm showed the values ˂1 and greater than zero in all adsorption concentrations which suggest that the adsorption process of diclofenac sodium on bentonite –puf surface is favorable. the characteristic adsorption energy eo calculated from dubinin-radushkevich isotherm for diclofenac sodium equal to 5 kj/mol indicates that the adsorption process physical in nature of diclofenac sodium on bentonite – puf surface .this results approached to results finding by [2]&[10]. 5.7. characterization bentonite is considered one of the most abundant natural materials available in nature that can be used for adsorption pollutant from wastewater and other application [46]. a.a. majeed, et al./ iraqi journal of chemical and petroleum engineering11,1 (2018) 29-43 03 the chemical composition of natural bentonite is different depending on the source of collection. the commercial bentonite xrd shown in fig.(14). bentonite polyureaformaldehyde composite predominantly had a dark brown appearance. a typical xrd pattern of bentonite polyureaformaldehyde composite after mixing shown in fig.(15) .ftir spectra for bentonite , polyureaformaldehyde and bentonite polymer composite shown in fig.(16,17,18) its seems shifting and missing groups. sem image for raw material and composite shown in fig.(19,a and b) it can be seen gathering of many microfine particles in bentonite -puf composite compare with bentonite surface which lead to rough surface with presence of pore structures. fig.10, effect of ph on both adsorption capacity and removal efficiency of ibuprofen, experiment conditions (adsorbent mass =0.05g,r.p.m=180,intial concentration =40µg/ml, temperature =47˚c and contact time 15 min). fig. 11, effect of ph on both adsorption capacity and removal efficiency of diclofenac sodium, experiment conditions (adsorbent mass =0.05g,r.p.m=180,intial concentration =40µg/ml, temperature =47˚c and contact time 15 min). fig. 12, comparison between experimental and model isotherms for ibuprofen fig. 13, comparison between experimental and model isotherms for diclofenac sodium fig. 14, xrd of bentonite a.a. majeed, et al./ iraqi journal of chemical and petroleum engineering11,1 (2018) 29-43 03 fig. 15, xrd for bentonite poly urea formaldehyde composite fig. 16, ftir spectra for ureaformaldehyde resin fig.(17):ftir spectra for bentonite fig. 18, ftir spectra for bentonite -puf composite (a) (b) fig. 19, sem image for (a) bentonite (b)bentonite-puf composite a.a. majeed, et al./ iraqi journal of chemical and petroleum engineering11,1 (2018) 29-43 33 table 7. adsorption isotherm constants parameters and error values for ibuprofen isotherm model constants value accuracy langmuir qmax 35.71429mg/g χ 2 2.305038 kl 0.213577 l/mg r 2 0.7557 r20 0.189698 rmse 3.043193 r40 0.104788 are 0.17738 r75 0.05876 r100 0.0447 freundlich's kf 2.208((mg/g) (l/mg) 1/n ) χ 2 54.6839 1/n 0.1311 r 2 0.7922 rmse 17.7558 are 0.81887 temkin a 3.578971 l/g χ 2 2.2796 b 430.5402 r 2 0.9109 rmse 2.42305 are 0.18328 dubinin-radushkevich qdr 27.629 mol/g χ 2 1.22724 β 7e-07 mol 2 /kj 2 r 2 0.9124 eo 0.8451 kj/mol rmse 2.21678 are 0.12162 table 8. comparison between experimental and model isotherms for diclofenac sodium isotherm constants accurcy langmuir qmax 11.94743 χ 2 6.130058 kl 8.2 r 2 0.9257 r20 0.006061 rmse 6.75862 r40 0.00304 are 0.198062 r75 0.001623 r100 0.001218 freundlich's model kf 21.29559 χ 2 0.375814 1/n 0.3385 r 2 0.9907 rmse 1.737598 are 0.055589 temkin a 49.3063 χ 2 2.458081 b 422.7413 r 2 0.9135 rmse 3.426319 are 0.187223 dubinin-radushkevich qdr 28.14304 χ 2 6.642404 β 2e-08 r 2 0.8191 eo 5 rmse 6.457195 are 0.21193 a.a. majeed, et al./ iraqi journal of chemical and petroleum engineering11,1 (2018) 29-43 33 6conclusions 1puf-bentonite composite prepared from mixing commercial bentonite with poly urea prepared in basic media in mixing ration of bentonite to polymer of 3g:1g is efficient for removal of diclofenac sodium and ibuprofen from wastewater 2 ph is the significant parameter affecting the adsorption capacity gives maximum removal of 99.8 for diclofenac and 99.2 for ibuprofen at ph 2 due to ionization of pharmaceutical compound . 3thermodynamic and kinetics parameters had been calculated and appears spontaneity of ongoing adsorption process for both pharmaceuticals studied and indicates the physical nature of adsorption of ibuprofen and diclofenac sodium. 4elovich's equation appear fit with both pharmaceuticals to describe kinetic model ,intraparticle diffusion model plot did not pass through the origin this indicates the external mass transfer played an important role in the diclofenac sodium and ibuprofen adsorption. references [1] m. nageeb, “adsorption technique for the removal of organic pollutants from water and wastewater,” in organic pollutants monitoring, risk and treatment, intech, 2013. [2] t. x. bui and h. choi, “adsorptive removal of selected pharmaceuticals by mesoporous silica sba15,” j. hazard. mater., vol. 168, no. 2–3, pp. 602– 608, 2009. [3] m. vadi, “comparative study of adsorption isotherms two non-steroidal anti-inflammatory eye drops, indomethacin and diclofenac on carbon nanotube,” orient. j. chem., vol. 28, no. 1, pp. 343– 348, 2012. [4] n. suriyanon, p. punyapalakul, and c. ngamcharussrivichai, “mechanistic study of diclofenac and carbamazepine adsorption on functionalized silica-based porous materials,” chem. eng. j., vol. 214, pp. 208–218, 2013. [5] j. l. sotelo, g. ovejero, a. rodríguez, s. álvarez, and j. garcía, “adsorption of several emerging contaminants in fixed bed columns by clay and activated carbon,” recent dev. chem. eng., vol. 661, no. 2, 2014. [6] m. m. io glu elif cal iskan salihi, “equilibrium and kinetic adsorption of drugs on bentonite: presence of surface active agents effect,” appl. clay sci., vol. 101, pp. 381–389, 2014. [7] h. guedidi, l. reinert, y. soneda, n. bellakhal, and l. duclaux, “adsorption of ibuprofen from aqueous solution on chemically surface-modified activated carbon cloths,” arab. j. chem., pp. 1–11, 2014. [8] s.-w. nam, d.-j. choi, s.-k. kim, n. her, and k.-d. zoh, “adsorption characteristics of selected hydrophilic and hydrophobic micropollutants in water using activated carbon.,” j. hazard. mater., vol. 270, no. january, pp. 144–52, 2014. [9] c. jung, l. k. boateng, j. r. v flora, j. oh, m. c. braswell, a. son, and y. yoon, “competitive adsorption of selected non-steroidal antiinflammatory drugs on activated biochars: experimental and molecular modeling study,” chem. eng. j., vol. 264, pp. 1–9, 2015. [10] s. jodeh, f. abdelwahab, n. jaradat, i. warad, and w. jodeh, “adsorption of diclofenac from aqueous solution using cyclamen persicum tubers based activated carbon (ctac),” j. assoc. arab univ. basic appl. sci., vol. 20, pp. 32–38, 2016. [11] r. s. joshi, n. s. pawar, s. s. katiyar, d. b. zope, and a. t. shinde, “development and validation of uv spectrophotometric methods for simultaneous estimation of paracetamol and ibuprofen in pure and tablet dosage form,” der pharm. sin., vol. 2, no. 3, pp. 164–171, 2011. [12] a. r. khaskheli, k. abro, s. t. h. sherazi, h. i. afridi, s. a. mahesar, and m. saeed, “simpler and faster spectrophotometric determination of diclofenac sodium in tablets , serum and urine samples,” pakistan j. anal. environ. chem., vol. 10, no. 1, pp. 53–58, 2009. [13] m. a. khan and and a. chourasia, “enhancement of dissolution rate of poorly soluble drug diclofenac sodium,” res. j. pharm. biol. chem. sci., vol. 3, no. 4, pp. 865–868, 2012. [14] b. boulinguiez, p. le cloirec, and d. wolbert, “revisiting the determination of langmuir adsorption onto activated carbon,” langmuir, vol. 24, no. 13, pp. 6420–6424, jul. 2008. [15] c. a. okuofu, “isothermal and batch adsorption studies of the use of borassus aethiopium and cocos nucifera for wastewater treatment,” am. int. j. contemp. res., vol. 2, no. 7, pp. 119–130, 2012. [16] l. s. chan, w. h. cheung, s. j. allen, and g. mckay, “error analysis of adsorption isotherm models for acid dyes onto bamboo derived activated carbon,” chinese j. chem. eng., vol. 20, no. 3, pp. 535–542, 2012. [17] a. vikram, s. firoz, d. kishore, y. c. mouli, and t. venkataramudu, “asian journal of pharmaceutical science & technology formulation and evaluation of mefenamic acid tablets by using modified starch,” vol. 2, no. 2, pp. 46–53, 2012. [18] h. moazed and t. viraraghavan, “removal of oil from water by bentonite organoclay,” pract. period. hazardous, toxic, radioact. waste manag., vol. 9, no. 2, pp. 130–134, apr. 2005. [19] h. b. oleiwi, “treatment and reuse of produced water from al-ahdab iraqi oilfields,” university of baghdad, 2014. a.a. majeed, et al./ iraqi journal of chemical and petroleum engineering11,1 (2018) 29-43 33 [20] j. l. sotelo, a. rodraguez, s. lvarez, and j. garca, “removal of caffeine and diclofenac on activated carbon in fixed bed column,” chem. eng. res. des., vol. 90, no. 7, pp. 967–974, 2012. [21] h. guedidi, l. reinert, y. soneda, n. bellakhal, and l. duclaux, “adsorption of ibuprofen from aqueous solution on chemically surface-modified activated carbon cloths,” arab. j. chem., pp. 1–11, 2014. [22] r. khatem, r. ojeda, and a. bakhti, “use of synthetic clay for removal of diclofenac antiinflammatory,” eurasian j. soil sci., vol. 4, no. 2, pp. 1–11, 2015. [23] k. steinby, r. silveston, and b. kronberg, “the effect of temperature on the adsorption of a nonionic surfactant on a pmma latex,” j. colloid interface sci., vol. 155, no. 1, pp. 70–78, jan. 1993. [24] z. k. nam sw, choi dj, kim sk, her n, “adsorption characteristics of selected hydrophilic and hydrophobic micropollutants in water using activated carbon.,” j hazard mater., vol. 15, no. 270, pp. 144–52, 2014. [25] s. álvarez, r. s. ribeiro, h. t. gomes, j. l. sotelo, and j. garcía, “synthesis of carbon xerogels and their application in adsorption studies of caffeine and diclofenac as emerging contaminants,” chem. eng. res. des., vol. 95, pp. 229–238, 2015. [26] h. guedidi, l. reinert, j.-m. lévêque, y. soneda, n. bellakhal, and l. duclaux, “the effects of the surface oxidation of activated carbon, the solution ph and the temperature on adsorption of ibuprofen,” carbon n. y., vol. 54, pp. 432–443, 2013. [27] h. khazri, i. ghorbel-abid, r. kalfat, and m. trabelsi-ayadi, “removal of ibuprofen, naproxen and carbamazepine in aqueous solution onto natural clay: equilibrium, kinetics, and thermodynamic study,” appl. water sci., no. 1 m, 2016. [28] p. banerjee, p. das, a. zaman, and p. das, “application of graphene oxide nanoplatelets for adsorption of ibuprofen from aqueous solutions: evaluation of process kinetics and thermodynamics,” process saf. environ. prot., vol. 101, pp. 45–53, 2016. [29] s. kittappa, m. cui, m. ramalingam, s. ibrahim, j. khim, y. yoon, s. a. snyder, and m. jang, “synthesis mechanism and thermal optimization of an economical mesoporous material using silica: implications for the effective removal or delivery of ibuprofen,” plos one, vol. 10, no. 7, p. e0130253, 2015. [30] t. o. carvalho, a. e. b. matias, l. r. braga, s. m. evangelista, and a. g. s. prado, “calorimetric studies of removal of nonsteroidal antiinflammatory drugs diclofenac and dipyrone from water,” j. therm. anal. calorim., vol. 106, no. 2, pp. 475–481, 2011. [31] m. antunes, v. i. esteves, r. gu??gan, j. s. crespo, a. n. fernandes, and m. giovanela, “removal of diclofenac sodium from aqueous solution by isabel grape bagasse,” chem. eng. j., vol. 192, pp. 114–121, 2012. [32] m.-t. sheu, h.-o. ho, p.-y. wang, y.-b. liou, and a.-b. wu, “photolysis of nsaids. i. photodegradation products of carprofen determined by lc-esi-ms.,” j. chromatogr. sci., vol. 41, no. 4, pp. 200–4, 2003. [33] h. yuh-shan, “citation review of lagergren kinetic rate equation on adsorption reactions,” scientometrics, vol. 59, no. 1, pp. 171–177, 2004. [34] h. khazri, i. ghorbel-abid, r. kalfat, and m. trabelsi-ayadi, “removal of ibuprofen, naproxen and carbamazepine in aqueous solution onto natural clay: equilibrium, kinetics, and thermodynamic study,” appl. water sci., pp. 1–10, apr. 2016. [35] k. mphahlele, m. s. onyango, and s. d. mhlanga, “adsorption of aspirin and paracetamol from aqueous solution using fe/n-cnt/??-cyclodextrin nanocomopsites synthesized via a benign microwave assisted method,” j. environ. chem. eng., vol. 3, no. 4, pp. 2619–2630, 2015. [36] m. t. mupa m, m. m, and g. u. and d. f, “preparation of rice hull activated carbon for the removal of selected pharmaceutical waste compounds in hospital effluent,” j. environ. anal. toxicol., vol. s7, 2015. [37] m. c. ncibi, “applicability of some statistical tools to predict optimum adsorption isotherm after linear and non-linear regression analysis,” j. hazard. mater., vol. 153, no. 1, pp. 207–212, 2008. [38] a. s.vakharkar, “adsorption studies for arsenic removal using modified chabazite,” university of south florida, 2005. [39] k. w. ahmed, “experimental and modeling for the removal of multi-pollutants by adsorption,” university of baghdad, 2006. [40] j. c. (john c. crittenden, montgomery watson harza (firm), and wiley interscience (online service), mwh‟s water treatment principles and design. john wiley and sons, 2012. [41] y. zhao, s. yang, g. wang, and m. han, “adsorption behaviors of acetaminophen onto the colloid in sediment,” polish j. environ. stud., vol. 24, no. 2, pp. 853–861, 2015. [42] f. a. dawodu, g. k. akpomie, and i. c. ogbu, “isotherm modeling on the equilibrium sorption of cadmium ( ii ) from solution by agbani clay,” int. j. multidiscip. sci. eng., vol. 3, no. ii, pp. 9–14, 2012. [43] s. kundu and a. k. gupta, “arsenic adsorption onto iron oxide-coated cement (iocc): regression analysis of equilibrium data with several isotherm models and their optimization,” chem. eng. j., vol. 122, no. 1–2, pp. 93–106, 2006. a.a. majeed, et al./ iraqi journal of chemical and petroleum engineering11,1 (2018) 29-43 30 [44] b. das, n. k. mondal, r. bhaumik, p. roy, k. c. pal, and c. r. das, “removal of copper from aqueous solution using alluvial soil of indian origin: equilibrium, kinetic and thermodynamic study,” j. mater. environ. sci., vol. 4, no. 4, pp. 392–409, 2013. [45] h. mansouri, r. j. carmona, a. gomis-berenguer, s. souissi-najar, a. ouederni, and c. o. ania, “competitive adsorption of ibuprofen and amoxicillin mixtures from aqueous solution on activated carbons.,” j. colloid interface sci., vol. 449, pp. 252–60, jul. 2015. [46] l. al-khatib, f. fraige, m. al-hwaiti, and o. alkhashman, “adsorption from aqueous solution onto natural and acid activated bentonite,” am. j. environ. sci., vol. 8, no. 5, pp. 510–522, 2012 ijcpe vol.10 no.1 (march 2009) iraqi journal of chemical and petroleum engineering vol.10 no.1 (march2009) 29-34 issn: 1997-4884 the factors affecting the absorption of ozone in water abbas h. sulaymon * , abdul razzak h. al.karaghouli and mustafa hassan flayeh * environmental engineering department college of engineering university of baghdad – iraq abstract this study was concerned with using ozone gas in drinking water treatment plant at ibn-sina company. the main purpose of this research is to find the best contactor for ozone unit proposed. an investigation was conducted to study the absorption of ozone by water in two type of absorber. the effects of the process variables (such as height of water column, contact time, and ph) on the amount of ozone absorbed were investigated. box-wilson central composite rotatable design is used to design the experimental work for the mentioned variables. it was found that the optimum value of the variables studied was: i) height of water column (90 cm) ii) contact time (17-18 min) iii) ph (7 7.5) introduction the degradation of raw source water has become a worldwide problem, and more serious in developing countries. safe and healthy drinking water are paid more and more attention. the rapid economic development and increasing polluted sources water put forward the need for advanced purification of drinking water in order to remove the trace pollutants in the water after conventional treatment. along with the pollution of sours water, more and more importance has been attached to the technologies on advanced purification of drinking water, of which ozonation process has got yearly investigation and found wide use in the world [1]. ozone (o3) or trioxygen is a molecule composed of three oxygen atoms, temporarily existing in a very unstable and reactive state. ozone is so reactive that a suitable container for storage probably does not exist. unlike the o2 molecule, this triatomic oxygen defies man’s attempts to store or liquefy it. compared to o2, o3 is an extremely active molecule, probably by a factor of 1,000 times and is sometimes referred to as activated oxygen [2]. ozone exists as a gas at room temperature. the gas is colorless with a pungent odor readily detectable at concentration as low as 0.02 to 0.05 ppm (by volume), which is below concentration of health toxic concern. ozone gas is highly corrosive and toxic [3,4]. since ozone cannot be stored or conveniently purchased by the gram, pound, gallon or ton, it must be produced on site as needed, (where needed and when needed) [3,5]. there is many way to produce ozone, all of the following can be used [2]. university of baghdad college of engineering iraqi journal of chemical and petroleum engineering the factors affecting the absorption of ozone in water 30 ijcpe vol.10 no.1 (march 2009) 1. electrical discharge – corona discharge. 2. electrolytically – electrolysis of an acid. 3. photo chemically – ultraviolet radiation. 4. radio chemically. some application of ozone to potable – water treatment is sterilization of all forms of bacteria and viruses; increased settling; removal of tastes, odors, and colors; oxidation of sulfides, cyanides, and algae; removal of trihalomethan precursors; and oxidation of organic materials. ozone oxidation followed by filtration also can be employed for the removal of iron and manganese [8]. a unit for treatment of water by ozonation including, on the one hand at least one apparatus for the production of ozonized white water and, on the other hand, at least one contactor in a way that the mixing of the water to be treated and the white water occurs in said contactor. the installation for the production of ozonized white water includes a device for dissolution of ozone in a carrier liquid [9]. the aim of the present work is concerned with detailed study of transfer of ozone into water. several variables have been investigated including, height of water column, contact time, and ph on the two types of absorbers packed and bubble column. experimental and materials experimental apparatus: ozone was transferred to water by using an absorption apparatus. the absorption unit consists of an absorption apparatus and ozone generator unit fig. (1). absorption apparatus: 1the packed column:the experiments in the present work were carried out using a (5 cm) i.d glass(q.v.f) column filled with one of three types of packing used in experiment, (10 mm in size) glass rashig rings, (18 mm in size) intalox saddles, and (15 mm in size) spherical packing. 2bubble diffuser:the bubble diffuser plays a basic and indispensable role in the present work. the bubble diffuser used was sintered glassware disk with diameter of 30 mm and pore size 100-160 micron. ozone generator: ozone generator used to generate the ozone has the following specification: type: fisher, model: 502, max dos: 10 g/hr at 500 liter o2/ hr ph-meter: the ph value of water before and after treating was measured by means of a digital ph-held with specifications as following: type: schott gerate, model: 820, range: 0-14 the experimental procedure: the raw water was transferred from tigris river at altarmyya city in the north of baghdad to the laboratory and left for one week to settling. the raw water was pumped by dosing pump from the top of column and distributed over the packing of column by buechnner funnels. ozonized oxygen gas produced from ozone generator, which calibrate first before starting the experiments at constant flow rate of oxygen gas and at different time (stripping the ozone gas by iodide solution), passes in counter current to water at the bottom of column and diffused through water by sintered glass disk. the diffuser at the first time, hot hydrochloric acid followed by several rinses of distilled water sucked through it under a good vacuum, this removes dust particles and powdered glass. the sintered glassware should remain in the oven at a temperature of (110 –150) c°. excess of ozone which was not absorbed by water passes through the contact column to the two gas washing bottles contain potassium iodide solution to captured the escaped ozone. with reference to (fig.1), an installation for the ozonation of water was essentially constructed from q.v.f column of 5 cm inside diameter and 200 cm height that permits the supply of a fluid. q.v.f column forms an absorption column, so as to obtain maximum dissolution of the ozone in the water with the help of the gas-liquid contactor with a minimum of loss, a packed column has been chosen. the column was filled with a packing material, in bulk, which in context of this research comprises of one of three types used, raschig ring, intalox saddle, and spherical packing. the column was fitted with an inlet for the water destined to be saturated with ozone. so as to allow a good distribution to the carrier liquid inside the column, a distribution device having the form of a sprinkler unit is installed at the inlet. the column has, in addition, to its lower part, a gaseous inlet. furthermore, the homogeneous distribution of the ozone over the whole cross-section of the column is achieved by a porous sintered device. abbas h. sulaymon, abdul razzak h. al.karaghouli and mustafa hassan flayeh 31 ijcpe vol.10 no.1 (march 2009) (1) q.v.f column, (6) ozone generator, (2) inlet liquid device, (7) oxygen bottle, (3) inlet gas device, (8) washing bottle, (4) sprinkler, (9) water tank. (5) porous sintered device, fig.1 absorption unit results and discussion effect of height of water column: the effect of height of water on the amount of ozone absorbed was studied in order to determine the height at which absorption process is best performed. figure (2) shows that for all contact time studied the amount of ozone absorbed by water increase as the height of water increases. similarly the relation between ozone concentration and the height of water was plotted for given ph values as shown in (fig. 3). the highest value of ozone concentration was obtained approximately at ph=7. referring to this figures it can be seen that the concentration of ozone increases with increases of height of water until height value of ( 90 cm ) after which the concentration of ozone is decreased with height of water column because the rise velocity of the bubbles decreased as well as the diameter of the bubble decreased. hieght of water column (cm) o z o n e c o n c e n tr a ti o n ( p p m ) 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 20 40 60 80 100 120 140 160 t= 25 min t= 20.7 min t= 15 min t= 9.2 min t= 5 min fig. 2 ozone concentration vs height of water column at various contact times. height of water column (cm) o z o n e c o n c e n tr a ti o n ( p p m ) 1.6 2.2 2.8 3.4 4.0 4.6 20 40 60 80 100 120 140 160 ph= 9 ph= 8.1 ph= 7 ph= 5.8 ph= 5 fig. 3 ozone concentration vs height of water column at various ph. height of water column (cm) o z o n e c o n c e n tr a ti o n ( p p m ) 3.3 3.5 3.7 3.9 4.1 4.3 4.5 20 40 60 80 100 120 140 160 t = 15 min ph = 7.0 fig. 4 ozone concentration vs height of water column the factors affecting the absorption of ozone in water 32 ijcpe vol.10 no.1 (march 2009) effect of contact time: the significant interaction effect between contact time and height of water column and between contact time and ph was shown in figs. (5) and (6). the best time of absorption of ozone by raw water is an important factor in water treatment affecting the concentration of ozone. examining these figures, it can be seen that the amount of ozone absorbed increases with increasing the time of absorption. it is clear that when the contact time is less than 18 minute, the ozone concentration is highest. while increase the contact above this value will decrease the ozone absorbed because the temperature of ozone generator increased and this will accelerate decomposition of ozone. contact time (min) o z o n e c o n c e n tr a ti o n ( p p m ) 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 2 6 10 14 18 22 26 30 l= 150 cm l= 124.6 cm l= 90 cm l= 55.3 cm l= 30 cm fig. 5 ozone concentration vs contact time at various height of water column. contact time (min) o z o n e c o n c e n tr a ti o n ( p p m ) 1.4 1.8 2.2 2.6 3.0 3.4 3.8 4.2 4.6 2 6 10 14 18 22 26 30 ph= 9 ph= 8.1 ph= 7 ph= 5. 8 ph= 5 fig. 6 ozone concentration vs contact time at various ph. contact time (min) o z o n e c o n c e n tr a ti o n ( p p m ) 2.6 3.0 3.4 3.8 4.2 4.6 2 6 10 14 18 22 26 30 ph=7.0 l= 90 cm fig.7 ozone concentration vs contact time effect of acidity function: the effect of ph is clearly observed by the concentration of ozone in water. figures (8) and (9) show that increasing the ph will increase the concentration of ozone in water. it is clear from these figures that when ph is equal to 7-7.5 the ozone concentration is highest. the ph of the water is important because hydroxide ions initiate ozone decomposition, which involves the following reaction [18]: o3 + oh ho2 + o2 o3 + ho2 o2 + o2 ph o z o n e c o n c e n tr a ti o n ( p p m ) 1.6 2.2 2.8 3.4 4.0 4.6 4.5 5.5 6.5 7.5 8.5 9.5 l= 150 cm l= 124.6 cm l= 90 cm l= 55.3 cm l= 30 cm figure (8) ozone concentration vs ph at various height of water column. abbas h. sulaymon, abdul razzak h. al.karaghouli and mustafa hassan flayeh 33 ijcpe vol.10 no.1 (march 2009) ph o z o n e c o n c e n tr a ti o n ( p p m ) 1.4 1.8 2.2 2.6 3.0 3.4 3.8 4.2 4.6 4.5 5.5 6.5 7.5 8.5 9.5 t= 25 min t= 20. 7 min t= 15 min t= 9. 2 min t= 5 min figure (9) ozone concentration vs ph at various contact time. ph o z o n e c o n c e n tr a ti o n ( p p m ) 3.5 3.7 3.9 4.1 4.3 4.5 4.5 5.5 6.5 7.5 8.5 9.5 l= 90 cm t = 18 min figure (10) ozone concentration vs ph analysis of experimental results: the absorption processes that take place between ozone gas and raw water start immediately when the gases come into contact with water. the two-film theory, the penetration theory, the surface renewal theory or others can describe this mass transport. in this work, however, two-film theory was considered as a basis of description of the transport characteristic for the absorption of ozone into water in bubble and packed bed absorber. the following assumption will be considered to treat the experimental result: 1ozone is the only active species that physically dissolves in water. 2there is no chemical reaction. comparison in results between two types of absorber used: comparison between types of absorber used in our experiments was represented in tables (1) and (2) these tables’ shows that the maximum amount of ozone absorbed achieved by using glass packing of rachig ring type and when the effective area increased the mass transfer coefficient decreased. table (1) amount of ozone absorbed by different type of absorber. height of water column ozone absorbed (ppm) bubble column packed column (cm) rachig ring spherical saddle 30 3.2 3.5 2.05 3.3 55.3 3.7 3.93 2.92 3.74 90 4.28 4.93 3.1 3.76 124.6 3.48 4.94 3.2 3.98 150 3.2 4.0 3.1 3.5 table (2) values of mass transfer coefficient type of absorber effective area m 2 /m 3 kl experimental m/s kl theoretical m/s p a c k in g rachig ring 163.39 1 * 10 -5 3.5 * 10 -5 intalox saddle 99.6 1.6 * 10 -5 4.7 * 10 -5 spherical 76.97 2.1 * 10 -5 4.5 * 10 -5 b u b b l e swarms bubble 133 1.2 * 10 -5 9 * 10 -5 conclusions the following conclusions could be drawn from this investigation: 1the second order polynomial regression analysis of the objective function i.e.; the amount of ozone absorbed by water and three variables (i.e.; height of water column, contact time, and ph) for bubble column contactor. the factors affecting the absorption of ozone in water 34 ijcpe vol.10 no.1 (march 2009) 2the amount of ozone absorbed increase with: aincreasing the height of water column. bincreasing contact time. cincreasing ph. the best operating conditions are: dheight of water( 90 cm ). econtact time( 18 min ). fph ( 7 ). 3the use of packed contactor (raschig ring) is better than bubble contactor, because the contact area is larger. references 1jinsong zhang, "studies and application on advanced purification of drinking water", "by internet". 2jim eaglton, "ozone in drinking water treatment" , feb. ( 1999 ) "by internet". 3rip g.rice & paul k.overbeck, "ozone and the safe drinking water act", gdt corporation, (1998), "by internet". 4dee smell & leslie s.ettre, "encyclopedia of industrial analysis", vol.16, pg. 538-551, (1972). 5ozone, national drinking water clearinghouse fact sheet, "by internet.” 6kirk othmer, "encyclopedia of chemical technology", 3 rd ed. vol.16, p.683-713, wiley, new york, (1981). 7us. patent, no. 5 843 307, des. (1998). 8rip g.rice & m.e.browning, "ozone treatment of industrial waste water", pollution technology review, no.84, (1981). 9united states protection agency (epa), office of water, "alternative disinfectants and oxidants guidance manual", april (1999), "by internet". 10rip g.rice, paul k.overbeck & ken larson, "ozone treatment of small water system", gdt corporation, oct. (1998), "by internet". 11colson j.m. & richardson j.e., "chemical engineering", vol.6, 2 nd . ed., pergamon press. (1968). 12treybal r.e, "mass – transfer operation", mc grawhill, 3rd ed., (1980). العوامل المؤثرة على أمتصاص االوزون في الماء عجذ انشصاق انقشِ غٕني ٔ يصطفى حسٍ فهيح, عجبس حًيذ سهيًٌٕ * انعشاقثغذادجبيعخ ثغذادكهيخ انُٓذسخ-قسى ُْذسخ انجيئخ * :الخالصه ٔصاسح انصُبعـّ / نـقـذ اْـتى ْزا انـجحث ثـذساسخ استخذاو االٔصٌٔ في يجبل يعبنجخ ييبِ انششة نصبنح ششكخ اثٍ سيُب انعبيّ انٓذف انشئيسي يٍ ْزا انجحث ْٕ ايجبد افضم انطشق الَتقبل االٔصٌٔ نهًبء ثبستخذاو َٕعيٍ يٍ اثشاج .ٔانًعـبدٌ انـعشاقيّ ٔانـذانـّ , صيـٍ انتًبس, تـى دساسـخ عـذح يتغيشاد ْـي استـفبع عـًٕد انـًبء في انـجشج. االيتصبص، انجشج انفقبعي ٔثشج رٔ حشِٕ (. ph)انحـبيـضـيّ نـهـًـبء انًـسـتـخـذو (box-wilson central composite rotatable design) تـى تـحذيـذ انتـجـبسة حـسـت طشيـقخ : نـهًـتغـيشاد انًجـيـُّ أعالِ ٔقذ ٔجـذ ثأٌ افضم ايتصبص نالٔصٌٔ يكٌٕ عُذ انقيى انتبنيّ ( سى90)طـٕل عًـٕد انًـبء في انجـشج -1 ( دقيق18ّ17)صيـٍ انتًـبس -2 (7.5 7 )انـذانّ انحـبيضيـّ -3 ijcpe vol.10 no.2 (june 2009) iraqi journal of chemical and petroleum engineering vol.10 no.2 (june 2009) 35-42 issn: 1997-4884 anodic polarization of anodized aluminum alloy 5052 dr. aparel s. yaro * and ala’a mishgel ali al-asade * chemical engineering department college of engineering university of baghdad – iraq abstract aluminum alloy 5052 had been anodized by sulfuric acid as an electrolyte under constant voltage and the anodic oxide film produce will be testing by potentiostatic anodic polarization .two variables, whi ch were considered as important variables, were studied. these variables are anodizing time 15,30 min. and sealing time 10,20 min., and the test by potentiostatic anodic polarization through electro chemical polarization measurements in solutions of 1n na2 so4 ( ph= 1 ). the results are discussed in light of the rate of ionic current flow through the coating during anodic polarization measurements. introduction when aluminum is exposed to the atmosphere, aluminum oxide can be formed on the aluminum surface. this oxide film is called (natural oxide film). the thickness of the air formed oxide film is very small therefore it can not be used as a protective film for preventing corrosion (l.young 1961). anodizing is a method of producing a `thickened oxide film on aluminum alloys by electrolytic means (burns 1967). anodizing also can be defined as an electro-chemical process by which the surface of a metal material, commonly aluminum is oxidized to form a porous and durable surface coating. the aluminum part, which becomes the anode, is submerged in a solution, commonly sulfuric acid, while a current is applied the anodizing process using sulfuric acid process, which is common, has advantages of lower cost, rapid action and comparatively low operating voltage. the latter is a consequence of the high conductivity of the electrolyte and its ability to penetrate the film to the underlying metal. the electrolyte has a solvent action upon the film which affects its character (franklin 1961). this process was patented by gower and brien in 1927 (gower, brien 1927). a wide range of operating conditions was used to meet specific requirement such as temperature, current density, concentration of acid, processing time, and the basic metal used (new man 2002). a normal process involves a 5-20% by volume solution of sulfuric acid and generally is operated at temperature of 20-25oc and at an anodizing current density of 1.2-1.6 a/dm2 at 18-24 v, processing times vary from 15-60 min., depending on the alloy treated and film thicknesses desired. the film thickness by this process is up to 25 m (canning 1970) (henley 1982), (defence stun 1997). sealing sealing of the oxide film is the final chemical operation in anodizing. it is well established that the anodic coatings formed on aluminum in sulfuric acid, phosphoric acid, or oxalic acid electrolyte consist of two portions, a very thin non-porous barrier oxide layer and relatively thick porous layer. the highly porous oxide films contain a huge number of tiny cells, each with a central pore. it is understandable that the porous structure, with a very high specific surface area, has a strong tendency to absorb water university of baghdad college of engineering iraqi journal of chemical and petroleum engineering anodic polarization of anodized aluminum alloy 5052 2 ijcpe vol.10 no.2 (june 2009) and other aggressive agents from the surrounding environment, leading to structural and physical damages of the anodized aluminum. sealing is a post treatment of anodizing to fill and close or plug the micro pores of anodic coatings by means of chemical conversion, physical absorption, or chemical impregnation that takes place within the pores. the understanding of sealing is essentially based on the investigation of the hydrothermal process carried out in hot water or steam at temperatures above 95°c. it is generally accepted that in hydrothermal sealing process the anhydrous oxide ( al2o3 ) in an anodic coating is partially hydrated to form boehmite–like crystals alo(oh).the basic reaction of hydrothermal sealing may be expressed by the following transformation taking place at temperatures above 90°c ( metalast 2001 ). )(2232 ohaloohoal  the most common sealing treatment consist in exposure to boiling water or steam for a period of time about equal to that of the anodic treatment. during this treatment the an hydrous aluminum oxide on the surface is converted to crystalline alpha monohydrate ( boehmite ). the hydrated product is essentially the same as that formed when aluminum reacts with water under the same conditions (spooner 1961). the density of the monohydrate is less than that of the oxide, the accompanying volume increase seals the mouths of the pores to a depth depending on the treating time. thin films will be completely hydrated, including the barrier layer, but normal coatings, in which the pore diameter is small relative to pore depth, will not be completely hydrated. (hunter 1959). on heating sealed anodic films, loss of weight at temperatures well below the decomposition temperatures of the monohydrate indicated that not more than 20 % of the water content ( spooner 1961 ). the sealing operation must be carefully controlled to obtain a uniform product. sealing in demineralized water provides better protection than dose treatment in tap water at a corresponding ph. the ph of the sealing water is important. in commercial practice a ph in the range of 5.6 6.6 is used . (henley 1982). sealing process is achieved by means o f boiling water. ( mason and slunder 1947 ). sealing by salt hydrolysis, using solutions of nickel or cobalt acetate at 90oc, is suitable for sealing dyed coatings. the salts are hydrolyzed and precipitated as the hydroxides, which are nearly colorless, and help stabilize the color (burns 1997). physical sealing used when substances provided a physical blocking of the coating pores. a wide range of organic materials has since been used for physical sealing. they have some advantages in special applications. for example sealing in lubricating oil or graphite / oil suspensions provides a lubricating surface that has been used for piston (henley 1982) . polarization the change of potential of electrode due to the passing of current from or out of it is called polarization measurement is probably the most used method for studying the corrosion behavior of metal in corrosive media. metallic surfaces can be polarized by the application of an external voltage which causes current flows between anode and cathode caused a change in the electrode potential. this change is termed as polarization and it affect the rate of corrosion. direct polarization measurements of potential versus current density not only provide the basis for computing the corrosion rate at any given potential , but from comparison with different models of electrode reactions often indicate the mechanism by which the reactions occur.(burns 1967). polarization is important in understanding corrosion behavior and corrosion reaction mechanism. it is of primary importance to know whether a metal is active or passive in a given environment, and significant information on this point can be obtained from polarization studies. polar graphic methods may be used to determine the initial rates of corrosion of metals in aqueous media since they are suitable for the detection of trace amounts of metal ions in solution. electrochemical studies usually provide the most fundamental knowledge of corrosion mechanism. polarization curves obtained by the potentiostatic technique, in which a given potential is impressed on the specimen and the resulting current measured, are particularly valuable in studying the formation and growth of passive films (greene 1962). experimental work this work is to study the formation of anodic oxide film on the aluminum alloy 5052 by means of sulfuric acid as an electrolyte under constant voltage , the electrolyte concentration: 15 wt % h2so4, dr. aparel s. yaro and ala’a mishgel ali al-asade 3 ijcpe vol.10 no.2 (june 2009) temperature: 45°c, current density: 1.4 a/dm2 , time of anodizing: 15,30 min., sealing time: 10,20 min. and the anodic oxide film produce will be testing by potentiostatic anodic polarization through electro chemical polarization measurements in solutions of na2so4 ( ph= 1 ) .when the anode is aluminum alloy 5052, the cathode in commercial practice, is stainless steel or lead. the current is passed through the electrolyte, such as sulfuric acid. most of the oxygen that would have been liberated combines with the aluminum to form a layer of porous aluminum oxide while hydrogen is librated at the cathode. the specimens used into dimensions of (120.2) cm. the chemical composition of the aluminum alloy 5052 according to uk or usa specification (trethewey and chamber lain 1996) its composition was found as follows: 2.5% mg , 0.25% cr , 0.4% si max. and the reminder is aluminum. the chemical composition for the material according to the analysis of alnaser company was:(0.008% cu, 0.311% fe, 0.045% mn, 0.012% zn, 2.43% mg, 0.299% si,0.21% cr, and 96.65% al) description of anodizing process in this process the aluminum specimen was connected to the positive terminal where it becomes anode, while the stainless steel article was connected to the negative terminal to be the cathode. the two electrodes were held by means of jigs and pvc rack to hold them stable in the anodizing tank and this jigs connected to direct current power supply in the anodizing cell to supply the electrodes a maximum current of 0.6a and voltage of 25v. the voltmeter was connected to the electric circuit to measure the voltage applied. the anode and cathode are immersed in the anodizing solution. operating process to anodizing the specimen the following steps were followed in this stage: 1. the anodizing acid solution was prepared in desired concentration and placed in the anodizing cell. 2. the specimen was weighed before anodizing (w1). 3. both electrodes must be well connected directly to the current power supply. 4. each electrode surface was immersed in acid solution. 5. the temperature of anodizing acid solution was controlled by a thermostat was set to the desired operating temperature. 6. the power supply was switched so that a constant voltage was obtained where the electrodes were immersed in the solution. 7. maintaining constant voltage at the time of run (15, 30) min. 8. for each run at the end time while the power supply is on and the anode was removed from anodizing cell immediately. and then the power supply is switched off. 9. after the specimen was removed from anodizing cell rinsed with running water followed by distilled water to remove the excess solution on the specimen. 10. the specimen was dried by air and weighed after anodizing (w2). 11. sealing process was the final stage where the specimens was immersed in a boiling distilled water with ph= (5.5-6) for different sealing time= (10, 20) mints. 12. the specimen was rinsed with distilled water and dried by air. 13. to calculate the film thickness, the anodic oxide film must be removed by using stripping solution. 14. after the specimen was stripped it was rinsed with running water followed by distilled water to remove the excess stripping solution on the specimen and dried by air. 15. the specimen was weighted after stripping the anodic coating (w3). 16. the above steps were repeated for each run, and the average values for each two runs were taken. anodic polarization of anodized aluminum alloy 5052 4 ijcpe vol.10 no.2 (june 2009) electro chemical corrosion cell the test was carried out using a standard glass cell. the cell was equipped with a multi neck cell consisted of working, reference and counter electrode and one of these neck used for thermometer. the working electrode with dimension (120.2) cm aluminum alloy 5052. the counter electrode was a carbon electrode. the reference electrode was standard calomel electrode bridged by a laggin-haber probe. the distance between the electrode surface and the laggin-haber capillary was set at about the optimum value of 1mm to minimize the experimental error due to ir drop. a thermometer was used to shwon the solution temperature in the cell to be ±1oc by means of a thermostat control in the system. polarization data measurements before each test, the cell and electrodes were washed with running tap water, followed by demonized water, then supplying of 1n na2so4 solution to the cell. when the required temperature was attained, the working electrode was placed in position in the cell and immersed in the solution. the corrosion potential was measured every 1 minute for the remaining one hour by a digital voltmeter. then the power supply was switched on and the resistances were putted to maximum. the potential was changed by about 50mv in the positive direction .when the potential is about zero current density, the current was observed when stable after about l minute. the procedure adopted in this work is that the potential was changed manually at a nearly constant rate and the current value noted when stability was achieved. the procedure described above was used for the unprotected aluminum alloy 5052 and for protected aluminum alloy 5052 by anodizing in sulfuric acid and by seal sample in boiling water under the effect of optimum condition. results and discussion in this investigation, anodized coatings of different thickness produced from anodizing process at different times and degree of sealing were compared by potentiostatic anodic polarization through electro chemical polarization measurements. the results are discussed in light of the rate of ionic current flow through the coating during anodic polarization measurements. open circuit potential measurements the variation of the ocp of 5052 aluminum alloy with time of immersion in 1n na2so4 solution at 30, 45, 60oc have been studied fig.(4) shows this variation with time. it is clear that: the free corrosion potential shifts to more negative value with increasing in the temperature. after one hour immersion the steady state potential recorded at 30, 45, 60oc was found to be about -760, -780, -820mv relative to saturated calomel electrode. when interpreting open circuit potential data, one must consider factors such as oxygen, chloride concentration, and electrolyte all of which have a significant influence on the reading. finally, it can be stated that: a more negative reading of ocp is generally considered to indicate a higher probability of corrosion. evaluation of metal corrosion from the (absolute) free corrosion potential values may mislead engineers and cause errors in judgment if other factors are not taken into account. it must be stressed that the free corrosion potential measurements only reveals the corrosion probability at a given location and time. it is evident that longterm monitoring of the free corrosion potential reading is more meaningful. the reason of this variation with time depends and affected by many parameters ( i.e material purity, surface treatment, oxygen contact ... etc). sherif and narayan have suggested in their study that the open circuit potential of aluminum, like those of other corroding metals, is a mixed potential. equilibria that control this mixed potential include (sherif and narayan 1989). cathodic reactions reduction of dissolved oxygen (acid solution) oheho 22 444   reduction of h+ ions   2 22 heh dr. aparel s. yaro and ala’a mishgel ali al-asade 5 ijcpe vol.10 no.2 (june 2009) anodic reaction ealal 3 3   ehoalohal 3632 322   factors effecting anodic polarization 1. time of anodizing the curves of fig. (2& 3) show the effect of coating thickness produced from two different anodizing time (15&30 min.) and for different sealing time (10&20 min.). the anodic polarization curve for a bare (uncoated) specimen is also shown in both above mentioned figures for comparison. the curve for the bare specimen agrees with those published by other studies (jones d. 1969); for pure aluminum, except that the corrosion potentials of the 5052 alloy in this study are some what more active, because most of the alloying elements in aluminum decrease corrosion resistance and are added to improve mechanical properties. fig. (2 and 3) show that anodic polarization in acid sulfate solutions is sensitive to anodizing time, anodized coating thickness and the degree of seal imposed on a coating. anodized coatings of greater thickness and longer sealing time have higher atmospheric corrosion resistance by passing lower anodic currents through such coatings. it is also notable that anodic polarization was sensitive to anodizing time and coating thickness at certain sealing time. its clear that the anodic polarization curves in both above mentioned figure shifts towards potential axis. compared with the un anodized specimen, indicating the coating thickness increases the resistance to corrosion by decreasing the anodic current density leading to state that: the general effect of increasing anodizing time is associated with an increase in coating thickness, leading to a depress anodic current to lower values at all anodic potential 2. sealing time the initial and principle purpose of sealing is to further improve the corrosion resistance of anodized aluminum. it is generally accepted that in hydrothermal sealing process (i.e., in hot water or steam at temperature above 95 °c), the anhydrous oxide (al2o3) in an anodic coating is partially hydrated to form beohmide – like crystles ( alo ( oh ) ). the basic reaction of hydrothermal sealing may be expressed by (metalast 2001 ) : ))((2)( 232 b eo h mid eohaloohin ga n o d icco a toal  figs. (4 and 5) show the anodic polarization curves of two different coating thickness produced as a result of different anodizing times for sealed & unsealed coatings. it is clear from these two figures that: 1. the unsealed coatings permitted considerably higher currents than the sealed coating regardless the anodizing time or coating thickness. 2. the anodic polarization curves representing the sealing coatings shifts toward the potential axis indicating the effectiveness of sealing by decreasing the anodic current values for certain anodic potentials. 3. the anodic polarization curve is quite sensitive to the sealing of the coatings. the 10 and 20 min. seals, are usually considered as edequate for good protection exhibited considerably lower anodic currents than unsealed coating. fig. 1 free corrosion potential 5052 aluminum alloy at different temperature in 1n na2so4, ph=1 anodic polarization of anodized aluminum alloy 5052 6 ijcpe vol.10 no.2 (june 2009) fig.2 effect of coating thickness and the anodic polarization of anodized aa5052 at 45 o c in 1n na2so4, (ph=1), at sealing time of 20 min. fig.3 effect of coating thickness and the anodic polarization of anodized aa5052 at 45 o c in 1n na2so4, (ph=1), at sealing time of 10 min. fig.4 effect of sealing time on the anodic polarization of anodized aa5052, coating thickness=35m at 45 o c in 1n na2so4, (ph=1), at 15 min. anodizing time. fig.5 effect of sealing time on the anodic polarization of anodized aa5052, coating thickness=55m at 45 o c in 1n na2so4, (ph=1), at 30 min. anodizing time. dr. aparel s. yaro and ala’a mishgel ali al-asade 7 ijcpe vol.10 no.2 (june 2009) conclusions 1. electrochemical polarization measurements are sensitive to the presence of surface films and could possibly lead to improved methods for coating evaluations. 2. increasing the time of anodizing lead significantly to increase aluminum built-up rate. 3. anodic currents passed through the anodizing coating are function of coating thickness, degree of sealing and anodizing time. references 1. burns, r.m., and j. bradley, protective coatings for metals, third edition (1967). 2. canning nd co.ltd., canning hand book on electroplating , 21ed., birminghama ( 1970 ) . 3. defence standard 03-25/ issue 3, " sulfuric acid anodizing of aluminum and aluminum alloys " , ministry of defence ( 1997 ) . 4. franklin , r. w., “anodic oxide films " , academic press , p.214 ( 1961 ). 5. gower c., brien , s., an improved process for providing a resistance coating upon the surface of aluminum or aluminum alloys , gb pat. 290,901 ( 1927 ) . 6. greene, n.d., corrosion 18, 136t (1962). 7. henley, v.f. " anoding oxidation of aluminum and its alloys”, pergamon press, oxford, england, (1982). 8. hunter, m.s., and robinson, d.l., electroplaters’ soc. 46, 220 (1959) 9. l. young " anodic oxide films", academic press, london and new york , (1961). 10. jones, d. “corrosion” no.4. vol. 25, (1969) . 11. mason r.b., and slunder, c. j. eng.ch.em., vol. 39 , no 12 , p. 1602 (1947). 12. metalast international inc., " sealing enhance anodic coatings performance" ,by ling hao, ph.d. ( www. metalast .com ), ( 2001 ) . 13. newman , r., " anodizing aluminum " , ( www. focuser . com /atm/anodize/anodize.htm), ( 2002 ) . 14. sherif, k.p. and narrayan r., br. corrosion . j., vol. 24, no.3, (1989). 15. spooner , r.g., tech proc. am. "electroplaters" soc.48,69 ( 1961 ). 16. strazzi, e.,bellei,s., " aluminum finishing ",vol.10,no.3-4,p.145-153, (1997) 17. trethewey n.d., and j. chamberlain , "corrosion for science and engineering" , london group limited ( 1996 ). anodic polarization of anodized aluminum alloy 5052 8 ijcpe vol.10 no.2 (june 2009) aa 5052 * * ◦: 1n na2so4 ( ph= 1) iraqi journal of chemical and petroleum engineering vol.16 no.4 (december 2015) 19 issn: 1997-4884 comparative study of new re-ni-mo/al2o3 and conventional hydrodesulphurization catalyst abdul halim a. karim mohammed, hussein k. hussein and tariq m. naife chemical engineering department – college of engineering – university of baghdad abstract new types of hydrodesulfurization (hds) catalyst re-ni-mo/ γ-al2o3 was prepared and tested separately with two prepared conventional hds catalysts (ni-mo/ γ-al2o3 and co-mo//γ-al2o3) by using a pilot plant hydrotreatment unit. activities of three prepared hydrodesulfurization catalysts were examined in hydrodesulfurization (hds) of atmospheric gas oil at different temperatures 275 to 350 °c and lhsv 1 to 4 h -1 , the reactions conducted under constant pressure 40 bar and h2/hc ratio 500 ml/ml .moreover, the hydrogenation of aromatic (had) in gas oil has been studied. hds was much improved by adding promoter re to the ni-mo/al2o3 catalyst. the results showed that re-ni-mo/ γ-al2o3 have more activity in desulfurization than nimo//γ-al2o3 and co-mo/ γ-al2o3 catalysts. the efficiency of hydrodesulfurization was markedly reduced over the co -mo/ γ-al2o3.also the result showed that nimo//γ-al2o3 have a minimum aromatic content 15.44 %. key words: hydrodesulfurization, hydrogenation of aromatic, hds catalyst, physical adsorption introduction sulfur removal from petroleum derivatives is a very important industrial process. diesel fuel and gasoline must have much lower heteroatom content, and this is done by hydrotreating process. the main aim of hydrotreating is to diminish air pollution emissions, to avoid poisoning of noble metals and to improve the fuel quality. catalysts are use in a variety of applications from the production of consumer goods to the protection of the environment [1]. the reduction of diesel engine emissions is a rather complex issue with a number of possible solutions. one of these solutions is the improvement of diesel fuel quality, especially by lowering the sulfur and aromatics content and increasing the cetane number. lower levels of aromatics will help to maximize the regeneration cycle of the exhaust gas treatment devices in addition to the reduction of pm emissions. the two-stage hydrotreating has the flexibility to cope with the simultaneous reduction in sulfur and in aromatics [2]. extreme reductions in the sulfur content will have an enormous impact on the costs and technology for diesel fuel production. iraqi journal of chemical and petroleum engineering university of baghdad college of engineering comparative study of new re-ni-mo/al2o3 and conventional hydrodesulphurization catalyst 2 ijcpe vol.16 no.4 (dec. 2015) -available online at: www.iasj.net optimum design and efficient utilization of catalysts require a thorough understanding of the surface structure and surface chemistry of the active material. utilization of more active catalysts for hydrodesulfurization (hds) of liquid fuel would be the less costly and the most effective way for the refineries, because it would allow for avoiding modifications of plant installations [3]. usually the hds catalysts contain molybdenum sulfide promoted with cobalt or nickel and supported on a high surface area alumina, but it is difficult to prepare a kind of catalysts with high active metals content because of the limitation of support’s porous structure. currently, new catalysts appear for hds reactions, which contain active components. hds catalysts possess high catalytic activity, but they have the disadvantage of high cost. many investigations of the hydrotreatment of petroleum based feedstocks show that the current commercial catalysts based on molybdenum sulfide doped with ni or co do not have sufficient activity to meet today’s refinery requirements determined by the environmental standards [4]. to attain compliance in the future, new hydrotreatment catalysts are necessary for the hydrodesulfurization (hds) of feedstocks. to improve the performance of the hds catalyst, all steps in the preparation procedure should be considered. the key parameters are the choice of a precursor of the active species, support, promoter, synthesis and post-treatment of the synthesized catalyst [5]. in the last two decades, other transition metal sulfides have been investigated. the application of noble metal catalysts for deep hds is limited by their sulfur resistance. therefore, those catalysts are normally used when most of the sulfur compounds and h2s have been removed from the process stream. a new concept of bifunctional catalysts has been proposed to increase the sulfur resistance of noble metal hydrotreating catalysts. it combines catalysts supports with bimodal pore size distribution (e.g. zeolites) and two types of active sites. the first type of sites, placed in large pores, is accessible for organosulfur compounds and is sensitive to sulfur inhibition. the second type of active sites, placed in small pores, is not accessible for large s-containing molecules and is resistant to poisoning by h2s [6]. since hydrogen can easily access the sites located in small pores, it can be adsorbed dissociatively and transported within the pore system to regenerate the poisoned metal sites in the large pores. however, the need of catalysts having better hydrogenation properties would increase in the future, due to the necessity for hydroprocessing of the heavy oil fractions of petroleum and even deeper hds reactions [7]. since the re sulfide has higher hydrogenation activity than the mo or w sulfides [8], this capability of the re sulfide can greatly help in the development of a new generation of better hydrotreating catalysts, especially when the reaction mechanism requires or is predominantly through a prehydrogenation route, as it occurs in deep hds and hdn reactions. the objective of this study is an attempt to provide a new hds catalyst re-nimo/ γ-al2o3 and compared the efficiency and activity with traditional catalysts. abdul halim a. karim mohammed, hussein k. hussein and tariq m. naife -available online at: www.iasj.net ijcpe vol.16 no.4 (dec. 2015) 3 experimental work feedstock iraqi atmospheric gas oil (supplied by al-dura refinery -baghdad) is used as a feedstock in the present investigation. table 1 shows the specifications of iraqi gas oil. table 1, properties of atmospheric gas oil specification value specific gravity at 15.6 ˚c/15.6˚c 0.8289 api gravity 37.6 viscosity / 40 ˚c ,c.st 6.62 sulfur content ,wt. % 1.402 aromatic content ,wt. % 18.66 flash point, ˚c 82 pour point, ˚c -9 diesel index 63 aniline point, ˚c 71.5 cetane number 57 colour, astm 0.5 materials 1support alumina support (γal2o3) with spherical shape and an average diameter of 3mm was supplied by the fluka ag company. the properties of γal2o3 are tabulated in table 2. table 2 properties of /γ-al2o3 surface area, m 2 /g 280 pore volume, cm 3 /g 0.365 porosity 0.45 bulk density, g/cm 3 1.06 crushing strength, kg 18 loss in attrition, wt. % 1.6 2gases nitrogen nitrogen was supplied from baghdad company with purity 99.9 %. hydrogen hydrogen was supplied from baghdad company with purity 99.9 %. catalyst preparation 1impregnation apparatus the impregnation apparatus consists of a conical flask conducted with a separating funnel, vacuum pump, electric shaker and trip to absorb the moisture and gases for efficient deposition of metals oxides into the carrier, the flask fixed upon shaker to ensure good contacting between aqueous solution and alumina particles. the objective is impregnation of carrier with aqueous solution of metal salt which adjusted to concentration which gives desired metal loading. 2preparation of co-mo/γ-al2o3 catalyst the co-mo/γ-al2o3 catalyst was prepared by evacuation 100 g of γal2o3 to remove the adsorbed gases and moisture, then this alumina calcined in oven at 538 ˚c for 16 hours. the catalyst was prepared by impregnation method [9]. an impregnation aqueous solution was prepared by dissolving 11 g of cobalt carbonate, 4 g of phosphoric acid [h3(pmo12o40).30h2o], and 38 g of phosphomolybdic acid in 75 cm 3 of water with shaking then this solution was poured in the conical flask of the impregnation apparatus containing 100 g of dried gamma alumina. the impregnation took place in an impregnation apparatus for 3 hours. the impregnated carrier was air dried at 120 °c for 16 hours and then calcined at 538 °c for 16 hours. comparative study of new re-ni-mo/al2o3 and conventional hydrodesulphurization catalyst 4 ijcpe vol.16 no.4 (dec. 2015) -available online at: www.iasj.net 3preparation of ni-mo/γ-al2o3 catalyst the ni-mo/γ-al2o3 catalyst was prepared at the same apparatus, conditions and quantities mentioned above except for cobalt carbonate which was subsisted by nickel carbonate. 4preparation of re-ni-mo /γ-al2o3 catalyst re-ni-mo /γ-al2o3 catalyst was prepared by multistage technique. thus, the first step, ni-mo/γ-al2o3 was prepared as mentioned above. in the second stage 22.78 g of ni-mo /γal2o3 was impregnated with 25 cm 3 of an aqueous solution having 0.96 g nh4reo4 per liter solution. the impregnated material was air dried at120 ˚c for 16 hours and calcined at 538 ˚c for 16 hours [10]. catalytic activity test catalytic activity studies were carried out in a continuous hydrotreating pilot plant unit. the hydrotreating unit designed by (vinci technologies). the unit (shown in fig. 1) consists mainly of vertical tubular stainless steel reactor (17.5 mm i.d., 25.5 mm o.d. and 300 mm length) electrically heated in a two block oven, temperature controller, dosing pump, gas meter and high pressure separator. hydrogen gas was supplied to the unit from a hydrogen cylinder. fig 1 schematic diagram of the hydrodesulfurization unit abdul halim a. karim mohammed, hussein k. hussein and tariq m. naife -available online at: www.iasj.net ijcpe vol.16 no.4 (dec. 2015) 5 50 g of catalyst (catalyst layer length 23 cm) was loaded into the mid-section of the reactor, while the upper and lower sections were packed with ceramic balls (ceramic layer length 3.5 cm). the unit was purged with nitrogen to ensure oxygen removal from the system, the pressure increased gradually up to 65 bars for 3h to check leaks, then pressure reduced to 10 bar and change nitrogen by hydrogen with 99.99% purity. the static hydrogen pressure increased up to 65 bars to check the leaks again. the hydrogen pressure reduced to 5 bars to prepare the unit for sulfiding process. pre-sulfiding was carried out at pressure 30 bars, temperature 310˚c, and feed flow rate 1ml/min for 12h using gas oil with 1.402 wt. % sulfur content. the hydrotreating of gas oil was carried out at 40 bar hydrogen pressure, 1 to 4 h -1 lhsv, 275 to 350 ˚c reaction temperatures and hydrogen to hydrocarbon ratio 500 l/l. the liquid product was collected (after a stabilization period to attain a steady state, this time depends on operating conditions of sample) in a receiver from which samples were taken for analysis. results and discussion 1surface area and pore volume the specific surface area determination was carried out using the bet isotherm, nitrogen adsorption and desorption isotherms were measured on thermo finnegan type instrument. the specific surface area [sa] which is the area in m 2 of one gram of solid is calculated as in equation. 20 10 22400   na vm s ma … (1) where vm is the monolayer coverage, am is the area occupied by one molecule of adsorbate in the monolayer which is 0.162 nm 2 for nitrogen molecule, and n is avogadro’s constant, 6.02 x 10 23 molecules / mol. results of surface area and pore volume are tabulated in table 3. table 3, surface area and pore volume of prepared catalysts co-mo/ γ-al2o3 ni-mo/ γ-al2o3 re-ni-mo/ γ-al2o3 surface area, m 2 /g 178.5 191.4 235.23 pore volume, cm 3 /g 0.34 0.38 0.38 the results of surface area and pore volume values for three prepared catalysts show that maximum surface area has for re-ni-mo/γ-al2o3, this is due to the high quantity of mesoporous of prepared catalysts [11]. furthermore, a large specific surface area is preferable to providing large adsorption capacity, but the creation of a large internal surface area in a limited volume inevitably gives rise to large numbers of small sized pores between adsorption surfaces, high surface area usually has a high percentage of small pores, in general the use of re leads to the development of a porous system. co-mo/γ-al2o3 catalyst shows a minimum surface area and this may be due to blockage some pores in preparation steps [12], and this mean that a reduction in pore sites is occur and this lead to a reduction in the activity of catalyst. pores that are larger than necessary, lend little to improving diffusion characteristics and as the pore diameters of the catalyst increase the surface area decreases (at constant pore volume). activity, generally, decreases with decreasing of the surface area and loss in pore volume occurs in the smallest diameter pores first. comparative study of new re-ni-mo/al2o3 and conventional hydrodesulphurization catalyst 6 ijcpe vol.16 no.4 (dec. 2015) -available online at: www.iasj.net highest activity retention is maintained if pore volume is concentrated in a very narrow range of pore diameters. 2pore size distribution figures 2, 3 and 4 show the pore size distribution for three prepared catalysts. the co-mo/γ-al2o3 and nimo /γ-al2o3 catalysts showed a number of pores toward macro size diameter, while re-ni-mo/γ-al2o3 catalysts exhibit only meso-pores after active metal impregnation. this is certainly effect on pore-size distribution change with a decrease in total pore volume. r΄p ,a˚ fig.2, pore size distribution of prepared co-mo/ γ-al2o3 catalyst r΄p ,a˚ fig.3, pore size distribution of prepared ni-mo/ γ-al2o3 catalyst r΄p ,a˚ fig.4, pore size distribution of prepared re-ni/ γ-al2o3 catalyst 3catalytic test hds activity of the three prepared catalysts was tested in hydrotreatment pilot plant. effects of temperature and lhsv on sulfur removal figures 5 to 7 show the effect of temperature and lhsv on sulfur removal on three prepared hds catalysts. it can be observed from the figures that re-ni-mo/γ-al2o3 modified catalyst in general shows better sulfur removal than conventional catalysts (co-mo, ni-mo) at all the temperatures and lhsvs. this implies that the hds activity of promoter’s catalysts is improved the hds activity, for example, at 325 °c and 2 h -1 , the sulfur removal is 55.9 wt. % for re promoted catalysts, while sulfur removal for (co-mo) and (ni-mo) are 36.5 wt. % and 37.4 wt. % respectively, a decrease in lhsv from 2.5 to 1 h -1 a better range for sulfur removal for all catalysts. increasing the temperature generally leads to increase in hydrotreating conversion even at higher lhsv. this indicates that the rate of hds is fast enough at higher temperature to mask the effect of increase in lhsv. the increasing of sulfur removal at high reaction temperature may be attributed to that the unreactive sulfur compounds which abdul halim a. karim mohammed, hussein k. hussein and tariq m. naife -available online at: www.iasj.net ijcpe vol.16 no.4 (dec. 2015) 7 most properly belong to thiophene derivatives become activated enough to react with hydrogen .thus, the upper temperature value is limited by the undesirable side reactions such as hydrocracking reactions which are expected to occur at high temperature. as the lhsv increases sulfur conversion slightly decreases which means that the film diffusion has no effect on the reaction kinetics. the decrease in lhsv means that lesser quantity of gas oil contacting the same quantity of catalyst per time, while increasing in lhsv provides for a greater quantity of gas oil through the reaction per unit of time [13]. fig. 5, effect of lhsv on the sulfur removal of hydrotreated product for co-mo/γ-al2o3 fig. 6, effect of lhsv on the sulfur removal of hydrotreated product for ni-mo/γ-al2o3 fig. 7, effect of lhsv on the sulfur removal of hydrotreated product for re-ni-mo/γ-al2o3 effects of temperature and lhsv on aromatic content hydrogenation of aromatics may occur simultaneously in hds process. figures 8 to 10 show the aromatic content of the hydrotreated product. these figures indicate that the aromatic content decrease with increasing reaction temperature and decreasing of lhsv. the increase of reaction temperature leads to increase rate of hydrogenation of aromatic and decrease the equilibrium constant, as mentioned by girgis [14], while the lhsv decreasing leads to increasing the contact time. also, as temperature increases, the aromatic compounds are decomposed into smaller one which can more easily diffuse into the catalyst macro and mesopores and reach the inner active sites where the desulfurization reaction mainly occurs. figure 9 shows that nickel– molybdenum catalysts have a higher hydrogenation activity than cobalt– molybdenum (figure 8), at the same operating conditions, or greater saturation of aromatic rings. this means that increasing in residence time, which leads to offer a plenty of contact time of feedstock, with catalyst inside the reactor and lead to give a higher reduction in aromatic content. comparative study of new re-ni-mo/al2o3 and conventional hydrodesulphurization catalyst 8 ijcpe vol.16 no.4 (dec. 2015) -available online at: www.iasj.net fig. 8, effect of temperature on aromatic content of atmospheric gas oil for co mo/ γ-al2o3 catalyst fig. 9, effect of temperature on aromatic content of atmospheric gas oil for ni mo/ γ-al2o3 catalyst fig. 10, effect of temperature on aromatic content of atmospheric gas oil for re ni mo/ γ-al2o3 catalyst maximum aromatic reduction is achieved between (300–350 °c) because of the interrelation between thermodynamic equilibrium and reaction rates. for a given pressure, the optimum temperature is a function of the types of aromatic compounds in the feed and space velocity. conclusions hydrodesulfurization was improved when ni-mo/γ-al2o3 promoted with re metals and consequent increase in activity, also ni-mo/ γ-al2o3 catalyst is better for hydrogenation reactions than co-mo/γ-al2o3 and re-ni-mo/γal2o3. references 1b.s. clausen, h. topsøe, f.e. massoth, hydrotreating catalysis, in: j.r. anderson, i.m. boudart (eds.), catalysis science and technology, springer, berlin, 1996. 2b.h.cooper, b.b.l. donnis, appl. catal. a:general 137 (1996) 203. 3h. topsøe, b.s. clausen, f.e. massoth, in, catalysis: science and technology, 1996. 4s. eijsbouts, mayo s w, fujita k. unsupported transition metal sulfide catalysts: from fundamentals to industrial application.applied catalysis: a, 2007, 322: 58-66. 5h. qabazard, f. abuseedo, a. stanislaus, m. andari, m. absihalabi, fuel sci. technol.int. 13 (1995) 1135. 6j.g. weissman, e.i. ko, s. kaytal, appl. catal. a 94 (1993) 45. 7k.g. knudsen, b.h. cooper, h. topsøe, appl. catal. a 189 (1999) 205. 8j. quartararo, s. mignard, s. kasztelan, j. catal. 192 (2000) 307. 9chiyoda et al , “united states patent”, no.6063265, (2000). 10n. escalona et al, applied catalysis, characterization and reactivity of re(x)/γ-al2o3 catalysts abdul halim a. karim mohammed, hussein k. hussein and tariq m. naife -available online at: www.iasj.net ijcpe vol.16 no.4 (dec. 2015) 9 in hydrodesulfurization and hydrodenitrogenation of gas oil, effect of re loading , 234 (2002) 45–54. 11p.steiner, blekkan e.a., “catalytic hydrodesulphurization of light gas oil a over ni-mo catalyst”, fuel processing technology,1-12, 79, 2002. 12k..s.w.,sing,s.j.,gregg, adsorption surface area and porosity, acadmic press,inc.,1982. 13i. a. van parijs and fromen g. f., ind. eng. chem. prod. res. dev., vol. 25, no. 3, (1986). 14m.j. girgis, , and gates, b.c., ind. eng. chem. res. 30, 2021 (1991). ijcpe vol.11 no.2 (june 2010) iraqi journal of chemical and petroleum engineering vol.11 no.2 (june 2010) 1-13 issn: 1997-4884 removal of lead, cadmium, and mercury ions using biosorption abbas h. sulaymon, shahlaa e. ebrahim, tariq j. al – musawi , sama m. abdullah environmental engineering department-college of engineering-baghdad university e-mail: shahlaaaga@yahoo.com abstract the biosorption of pb (ii), cd (ii), and hg (ii) from simulated aqueous solutions using baker’s yeast biomass was investigated. batch type experiments were carried out to find the equilibrium isotherm data for each component (single, binary, and ternary), and the adsorption rate constants. kinetics pseudo-first and second order rate models applied to the adsorption data to estimate the rate constant for each solute, the results showed that the cd (ii), pb (ii), and hg (ii) uptake process followed the pseudo-second order rate model with (r 2 ) 0.963, 0.979, and 0.960 respectively. the equilibrium isotherm data were fitted with five theoretical models. langmuir model provides the best fitting for the experimental results with (r 2 ) 0.992, 0.9987, and 0.9995 for cd (ii), pb (ii), and hg (ii) respectively. the effect of various influent adsorbates concentrations, and flow rates on the performance of fixed bed adsorber was found for the three heavy metals. a mathematical model was formulated to describe the breakthrough curves in the fixed bed adsorber for each component. the results show that the mathematical model provides a good description of the adsorption process for cd (ii), pb (ii), and hg (ii) onto fixed bed of baker’s yeast biomass. keywords: biosorption, yeast, cd (ii), pb (ii), hg (ii), fixed bed, mathematical model, mass transfer coefficient. ________________________________________________________________________________________________ introduction the intensification of industrial activity during recent years is greatly contributing to the increase of heavy metals in the environment, mainly in the aquatic systems [1]. wastewater contained with heavy metals is a serious environmental problem because they do not undergo biodegradation and are accumulated into the organism entering into the food chains [2]. metals can be toxic to microbial population at sufficiently high concentrations. however, some metals are markedly more toxic even at very low levels [3]. among the toxic heavy metals, mercury, lead, and cadmium, “called the big three” are in the limelight due to their major impact on the environment; lead and cadmium are potent neurotoxic metals [4, 5] the sources of human exposure to cd (ii) include atmospheric, terrestrial and aquatic routes [6, 7]. the most severe form of cd (ii) toxicity in humans is “itai-itai”, a disease characterized by excruciating pain in the bone [8]. other health implications of cd(ii) in humans include kidney dysfunction, hepatic damage and hypertension [9]. however, it has been suggested that overall nutritional status (rather than mere cd (ii) content of food) is a more critical factor in determining cd (ii) exposure [10]. lead (ii) is heavy metal poison which forms complexes with oxo-groups in enzymes to affect virtually all steps in the process of hemoglobin synthesis and prophyrin metabolism. toxic levels of pb (ii) in man have been associated university of baghdad college of engineering iraqi journal of chemical and petroleum engineering removal of lead, cadmium, and mercury ions using biosorption ijcpe vol.11 no.2 (june 2010) 2 with encephalopathy seizures and mental retardation [11]. mercury pollution results from metallurgical industries, chemical manufacturing and metal finishing industries [12]. hg (ii) in the liquid form is not dangerous and it is used in a number of industries. in the vapor form mercury becomes very poisonous. it attacks the lungs, kidneys and the brain. the vapor crosses the blood-brain and blood stream [13]. adsorption has been shown to be the most promising option for all these non-biodegradable heavy metals for the removal from aqueous streams, activated carbons being the most common adsorbent for this process due to its effectiveness and versatility. although activated carbon, in granular or powdered form has a good capacity for the adsorption of heavy metals, it suffers from a number of disadvantages. activated carbon is quite expensive and the higher the quality the greater the cost. both chemical and thermal regeneration of spent carbon is expensive [14, 15]. alternatively, the so-called biosorption, i.e. the passive uptake of pollutants from aqueous solutions by the use of non-growing or nonliving microbial mass, thus allowing the recovery and/or environmentally acceptable disposal of the pollutants, could also be considered. “biosorption” term is used to indicate a number of metabolism-independent processes (physical and chemical adsorption, electrostatic interaction, ion exchange, complexation, chelation, and microprecipitation) taking place essentially in the cell wall rather than oxidation though anaerobic or aerobic metabolism (biodegradation). the main attractions of biosorption are high selectivity and efficiency, cost effectiveness and good removal performance [16, 17]. the use of dead microbial cells in biosorption is more advantageous for water treatment in that dead organisms are not affected by toxic wastes, they do not require a continuous supply of nutrients and they can be regenerated and reused for many cycles. dead cells may be stored or used for extended periods at room temperature without putrefaction occurring. moreover, dead cells have been shown to accumulate pollutants to the same or greater extent than growing or resting cells [18]. however, the use of dead biomass in powdered form in the column has some problems, such as difficulty in the separation of biomass after biosorption, mass loss after regeneration, low strength and density and small particle size, which make it difficult to use in column applications. to solve these problems, dead biomass can be immobilized in a supporting material [19]. yeast biomass plays an important role in investigations in the field of biosorption. yeast is an inexpensive, easily available source of biomass. yeast cells are known to bind various metal ions from solution under a wide range of external conditions [20, 21]. continuous packed bed column systems are the most suitable and economic ways to remove heavy metals, offering an alternative treatment for the removal and recovery of heavy metals in aqueous systems. breakthrough curves are necessary for the adsorption column design, due to the information about the dynamic behavior of the metal concentration of the effluent in time. another important factor for the column design is the maximum capability of adsorption of the metallic ion with a specific amount of biomass; this process is studied with the help of sorption isotherms. mathematical models were carried out for the adjustment of experimental breakthrough curves, and the dynamic behavior prediction of the column in biosorption processes. these models are useful for the sizing and optimization of the industrial scale process using laboratory data; mathematical models also enable the response and mechanisms prediction of the system [22, 23]. the aim of the present research is to investigate the lead, cadmium, and mercury ions biosorption processes using baker’s yeast as a biosorbent 2. mathematical models 2.1 kinetics models there are various kinetic models have been used for evaluating the intraparticle diffusion coefficients. the pseudo-first order rate expression of lagregren [21] is generally described by the following equation: (1) where qe and qt are the amounts of each solute (mg/g) adsorbed on the adsorbent at equilibrium, and at time t, respectively, and k1 is the rate constant (min _1 ). integrating and applying the boundary conditions, t = 0 and qt = 0 to t = t and qt = qe, eq. 1 takes the form: (2) abbas h. sulaymon, shahlaa e. ebrahim, tariq j. al-musawi, sama m. abdullah ijcpe vol.11 no.2 (june 2010) 3 while the linearized form of the pseudo-secondorder equation [24] is given by: (3) where, k2 is the rate constant of pseudo-secondorder biosorption (mg g _1 min _1 ); qe, the amount of metal adsorbed at equilibrium (mg g _1 ); and qt, the amount of metal adsorbed at time t (mg g _1 ). replacing the initial sorption rate k2 by h, one can get: (4) 2.2 breakthrough curves model a two parameters model for the modeling of breakthrough curves described by belter et al. [25] takes the form (5) where erf (x) is the error function of x, t is the column residence time, t0 is the time at which the effluent concentration is half the influent concentration, and σ represents the standard deviation which is a measure of the slope of the breakthrough curve. the model parameters t0 and σ can be estimated by fitting eq. 5 to experimental breakthrough data. since major process variables such as influent flow rate, column length, and adsorbent particle size are not incorporated in eq. 5, it is necessary to empirically correlate the two model parameters with these variables in order to use eq. 5 to simulate the dynamics of a biosorption column operated under varying experimental conditions [26]. matlab was used for the mathematical solution of the above equation. the breakthrough curve presented in terms of the dependence time of the relation between the final and initial cd (ii), pb (ii), and hg (ii) concentrations (c/c0). 3materials and methods 3-1 materials adsorbent: the yeast used in the experiments was supplied from pakgida company, turkey. adsorbates: cadmium, lead, and mercury ions were prepared by dissolving cadmium salt cd (no3)2, lead salt pb (no3)2.2h2o, and mercury salt hgcl2 in distilled water respectively. these solutions were kept at room temperature. 3.2 methods physical properties of bakery’s yeast were measured at oil research and development centre and listed in table 1. the non-living yeast biomass was dried in an oven at 120 o c for 24 hours before being used as adsorbent. the aqueous solution of cadmium, mercury, and lead were prepared from reagent grades, there properties are listed in table 2. table 1: characteristics of yeast table 2: main properties of cadmium, lead, and mercury ions adsorbate cd (ii) pb (ii) hg (ii) salt cd(no3)2 pb (no3)2 hgcl2 purity 98% 98.5% 97.6% solubility of the salt (mol/l) 7.21 1.57 2.8 manufacturing company fluka bdh fluka for the determination of adsorption isotherms, 250 ml flasks were filled with known concentration of solute and a known weight of yeast. the flasks were then placed on a shaker and agitated continuously for 30 hours at 30 o c. the concentration of solute in the solution was determined using atomic absorption spectrophotometer (type perkin-elmer -5000, usa). this experiment was carried out for single adsorb ate, binary and ternary adsorbates. the adsorbed amount is calculated by the following equation:   a eol e w ccv q   (6) the mass transfer coefficient for each adsorb ate was estimated using the following steps: estimating the optimum agitating speed for batch adsorber to reach the needed equilibrium concentration of cd (ii), pb (ii), and hg (ii). estimating the mass transfer coefficient (k2) in batch process at optimum bulk density (kg/m 3 ) 692.6 porosity 0.36 actual density (kg/m 3 ) 1406.5 surface area (m 2 /gm) 2.6599 removal of lead, cadmium, and mercury ions using biosorption ijcpe vol.11 no.2 (june 2010) 4 to drain heater and regulator column adsorber nnnn feed distributor feed tank effluent tank sampling point valve valve valve fine control valve valve centrifugal pump rotameter sampling point agitation speed for each component using pseudo-second order model. the mass transfer coefficient for cd (ii), pb (ii), and hg (ii) were obtained by using 2 liter pyrex beaker fitted with a variable speed mixer. the beaker was filled with 1 liter of known concentration solution and agitation started before adding the yeast. at time zero, the accurate weight of yeast was added. samples were taken every 5 minutes. the necessary dosage of yeast to reach equilibrium related concentration of ce/co equal 0.05, were calculated by using eq. 6. the fixed bed adsorber experiments were carried out in a glass column of 50 mm internal diameter and 50 cm height. a 100 gm of yeast was mixed with 480 gm glass beads of 1mm size (these weights were selected after many trials to fix the yeast in the bed) for each experiment in the fixed bed at different effluent concentrations and flow rates of cd, pb, and hg ions. the mixture of yeast and glass beads were confined in the fixed bed by fine stainless steel screen and two layers of fine texture at the bottom and glass packing at the top of the bed to ensure a uniform distribution of influent through the yeast bed. the influent solution was introduced to the column through a perforated plate fixed at the top of the column. feed solution was prepared in a stainless steel vessel supplied with immersed heater and a thermocouple to adjust the temperature of the solution to 30 o c. a schematic diagram of the apparatus is shown in fig. 1. fig. 1: schematic representation of experimental equipment abbas h. sulaymon, shahlaa e. ebrahim, tariq j. al-musawi, sama m. abdullah ijcpe vol.11 no.2 (june 2010) 5 4. results and discussion 4.1 adsorption isotherm the equilibrium isotherms display a nonlinear dependence on the equilibrium concentration. the adsorption data for both systems were fitted by langmuir model [27], freundlich model [28], radke-prausnitz model [29], reddlich-peterson [30] and combination of langmuir-freundlich isotherm model [31]. the determination coefficients are shown in table 3 for the cd (ii), pb (ii), and hg (ii) systems. table 3 indicates that langmuir model provides the best fit as judged by its correlation coefficient for the three components. table 3 parameters of isotherm for cd (ii), pb (ii), and hg (ii) and correlation coefficient for various models model parameters cadmium lead mercury langmuir e em e bc bcq q   1 qm, b, m 3 /kg correlation coefficient 0.373 13.154 0.9992 0.3101 205.5 0.9987 0.348 116.303 0.9995 freundlich n ee kcq /1  k, n, correlation coefficient 4.3453 1.27 0.9886 61.422 1.012 0.987 37.24 1.24 0.9766 radk-prausnitz rpn e rp rp erp e c f k ck q            1 1 krp, frp, nrp, correlation coefficient 25.62 0.812 .74401 0.9736 65.6 9.0572 -3.221 0.97599 34.6 5.2805 -1.58522 0.9773 reddlich-peterson rm er er cb ca q   1 ar, br, mr, correlation coefficient 5.1617 0.1 5.851808 0.9879 65.536 8.401 4.069189 0.9788 34.688 6.657 2.577402 0.9321 combination of langmuir-freundlich n e n em e bc cbq q 1 1 1  qm, b, n, correlation coefficient 15.29367 0.18667 1.14616 0.9939 138.955 1.01213 0.482614 0.9921 201.291 0.207137 0.779962 0.9943 the ph values for cd (ii), pb (ii), and hg (ii) were 6.22, 5.01, and 6.15 respectively and after mixing with yeast the ph values became 4, 4.6, and 5.4 respectively. the equilibrium isotherms for each single component cd (ii), pb, and hg (ii) onto yeast are presented in figures 2, 3, and 4 respectively, and the adsorption isotherms for each solute in the presence of other solutes are shown in figures 5, 6, and 7 respectively. fig. 8 represents the isotherm curve for the three solutes together, which showed the equilibrium isotherm of each solute is of favorable type. it was found that the amount of adsorbate adsorbed per unit mass of yeast for pb (ii) is greater than that for hg (ii) and cd (ii). this can be explained by the effect of solubility, where the solubility of lead nitrate salt in water is less than that of mercury chloride salt and cadmium nitrate salt, table 2. it will be expected to have a highest adsorption rate. furthermore it may be related to the molecular weight where the higher adsorption rate related to the higher molecular weight salt. pb(no3)2.2h2o> hgcl2 > cd (no3)2 removal of lead, cadmium, and mercury ions using biosorption ijcpe vol.11 no.2 (june 2010) 6 fig. 2: adsorption isotherm for cd (ii) onto yeast at 303 k fig. 3: adsorption isotherm for pb (ii) onto yeast at 303 k fig. 4: adsorption isotherm for hg (ii) onto yeast at 303 k fig. 5: adsorption isotherm for a binary system of pb (ii) and cd (ii) onto yeast at 303k abbas h. sulaymon, shahlaa e. ebrahim, tariq j. al-musawi, sama m. abdullah ijcpe vol.11 no.2 (june 2010) 7 fig. 6: adsorption isotherm for a binary system of pb (ii) and hg (ii) onto yeast at 303 k fig. 7: adsorption isotherm for binary system of hg (ii) and cd (ii) onto yeast at 303 k fig. 8: adsorption isotherm for ternary system of pb (ii), cd (ii), and hg (ii) onto yeast at 303 k removal of lead, cadmium, and mercury ions using biosorption ijcpe vol.11 no.2 (june 2010) 8 4.2 mass transfer coefficient the amounts of yeast used for adsorption of cd (ii), pb (ii), and hg (ii) were calculated for final equilibrium related concentration of ce/co=0.05. the initial concentrations for each solute was 0.1 kg/m 3 with the doses of yeast for cd (ii), pb (ii), and hg (ii) systems are 3.4×10 3 kg, 0.5×10 -3 kg, and 0.75×10 -3 kg respectively. the typical concentration decay curves of solute in batch experiments were carried out for cd (ii), pb (ii), and hg (ii) at different agitation speeds as shown in figures 9, 10, and 11 respectively. the optimum agitation speed needed to achieve ce/co=0.05 was found to be 1000 rpm. the adsorption data at optimum agitation speed for the three solutes were analyzed in terms of pseudo-first and second order mechanisms. the rate constant using pseudo-first order rate expression was obtained from the slope of the linear plots of log (qe–qt) against t for each solute using eq. 2. while, the rate constants for cd (ii), pb (ii), and hg (ii) by using pseudo-second order biosorption rate constant (k2) were determined from the slope and intercept of the plots of 1/qt against 1/t. using eq. 4. the values of the rate constants with the corresponding correlation are presented in table 4 for both mechanisms and for the three solutes. fig. 9: concentration-time decay curves for cd (ii) adsorption onto yeast at different agitation fig. 10: concentration-time decay curves for pb (ii) adsorption onto yeast at different agitation speed abbas h. sulaymon, shahlaa e. ebrahim, tariq j. al-musawi, sama m. abdullah ijcpe vol.11 no.2 (june 2010) 9 as can be seen from table 4, the correlation coefficients for the pseudo-first order kinetic model for the various solutes were found to be lower than that for the pseudo-second order kinetic. from table 4 pb (ii) has the largest value of pseudo-second and first order rate constants in comparison with hg (ii) and cd (ii). this enhances the results regarding pb (ii) for its fastest adsorption onto yeast. fig. 11: concentration-time decay curves for hg (ii) adsorption onto yeast a different agitation speed table 4: pseudo first and second order rate constants for cd (ii), pb (ii), and hg (ii) with correlation coefficients pollutant pseudo-first order kinetic model pseudo-second order kinetic model k1 (min -1 ) r 2 (correlation coefficient) k2 (mg/gm.min) r 2 (correlation coefficient) cd (ii) 0.002 0.516 6.099 10 -4 0.963 pb (ii) 0.016 0.856 1.259 10 -3 0.979 hg (ii) 0.005 0.804 9.6 10 -4 0.960 4.3 breakthrough curves 4.3.1 effect of influent concentrations figures 12, 13, and 14 show the experimental and predicted breakthrough curves for cd (ii), pb (ii), and hg (ii) respectively for adsorption onto bakery’s yeast at different initial concentrations of adsorbate at constant temperature of 303k. it can be seen that an increase in the initial concentration of cd (ii), pb (ii), and hg (ii) make the breakthrough curves much steeper, this would be anticipated on the basis that the driving force for mass transfer increases with increase of concentration of adsorbates in the solution [32]. a high adsorbates concentration may saturate the adsorbent more quickly, thereby decreasing the breakthrough time. the same conclusion was obtained by [33, 34, 35, and 36]. there is a good matching between the predicted and the experimental breakthrough curves. removal of lead, cadmium, and mercury ions using biosorption ijcpe vol.11 no.2 (june 2010) 10 fig. [12]: experimental and theoretical breakthrough curves for adsorption of cd (ii) onto yeast at different initial concentrations fig. 13: experimental and theoretical breakthrough curves for adsorption of pb (ii) onto yeast at different initial concentrations fig. 14: experimental and theoretical breakthrough curves for adsorption of hg (ii) onto yeast at different initial concentrations 4.3.2 effect of flow rates figures 15, 16, and 17 present the experimental and predicted breakthrough curves for cd (ii), pb (ii), and hg (ii) respectively for adsorption onto bakery’s yeast at different flow rates of adsorbate at constant temperature of 303 o k. an increase in the adsorbate flow rate decreases the breakthrough time due to the decrease in the contact time between the adsorbate and the adsorbent along the adsorption bed. increasing the flow rate may be expected to make reduction of the liquid film thickness. therefore, this will decrease the resistance to mass transfer and increase the mass transfer rate as well as there is not enough time for adsorption equilibrium to be reached. these phenomena agree with that obtained by [33, 34, 36, 37and 38]. abbas h. sulaymon, shahlaa e. ebrahim, tariq j. al-musawi, sama m. abdullah ijcpe vol.11 no.2 (june 2010) 11 fig. 15: experimental and theoretical breakthrough curves for adsorption of cd (ii) onto yeast at different flow rates fig. 16: experimental and theoretical breakthrough curves for adsorption of pb (ii) onto yeast at different flow rates fig. 17: experimental and theoretical breakthrough curves for adsorption of hg (ii) onto yeast at different flow rates conclusions the equilibrium isotherm data were correlated with five models for each solute, langmuir model gave the best fit for the experimental data for all of them. the batch experiments were helpful in estimating the optimum agitating speed for each solute and to find the rate constants for cd (ii), pb (ii), and hg (ii) by using pseudo-first and second order models, the results showed that the cd (ii), pb (ii), and hg (ii) uptake process followed the pseudo-second order rate model. a two parameters model for the modeling of breakthrough curves was used. an increase in the initial concentration of each adsorbate makes the breakthrough curves much steeper, which would be anticipated with the basis of increases driving force for mass transfer with the increase of adsorbates concentrations. the increase in the flow rate for each solute decreases the breakthrough time due to the decrease in the contact time between the adsorbate and the adsorbent along the adsorption bed. acknowledgment we would like to express our sincere thanks and deep gratitude to the ministry of higher education and scientific research, research and promotion office for supporting this work financially. removal of lead, cadmium, and mercury ions using biosorption ijcpe vol.11 no.2 (june 2010) 12 notation symbols ar reddlich-peterson model parameter b langmuir constant, l/mg br reddlich-peterson model parameter c concentration of fluid, kg/m 3 co initial concentration, kg/m 3 ce concentration of solute at equilibrium, kg/m 3 frp radke-prausnitz model parameter k freundlich empirical constant krp radke-prausnitz model parameter mr reddlich-peterson model parameter nrp radke-prausnitz model parameter n freundlich empirical constant vl volume of solution, m 3 wa mass of adsorbent, kg references 1-marques, p.a.s.s., rosa, m.f., pinheiro, h.m., (2000). ph effects on the removal of cu2‏, cd2‏ and pb2‏ from aqueous solution by waste brewery waste. bioprocess eng. 23, 135–141. 2-corneliu cojocarua, mariana diaconua, igor cretescua, jasmina savi , vesna vasi, (2009). biosorption of copper ions from aqua solutions using dried yeast biomass. colloids and surfaces a: physicochemical and engineering aspects. 335, 181-188. 3forstner u. and wittman g. t. w (1979). metal pollution in the aquatic environment. springer-verleg, berlin. pp. 13-17. 4volesky b, (1994). advances in biosorption of metals: selection of biomass types. fems. microbiol. rev.14:291-302. 5puranik pr, and paknikar km (1997). biosorption of lead and zinc from solution using streptoverticillium waste biomass. j. biotechnol. 55, 113-124. 6wolnik ka, frick fl, caper sg, meyer mw, satzergar rd, (1985). cadmium lead and eleven other elements in carrots field corn, onion, rice, spinach and tomatoes. j. agric. food chem. 33: 807-811. 7lopez mc, cabrea c, gallego c, lorenzo ml (1994). cadmium levels in waters of canada coast. arch. pharm. 1:945-950. 8yasuda m, miwa a, kitagawa m (1995). morphometric studies of renal lesions in “ itai-itai” disease: chronic cadmium nephropathy; nephron 69: 1419. 9klaassen cd (2001). heavy metals and hardmen jg, limbird le, gilman ag (eds). goodman and gilmans: the pharmacological basis of therapeutics, mcgraw hill, new york. pp. 1851-1875. 10vahter m, berghund m, nermell b, akesson a (1996). bioavailability of cadmium from shell fish and mixed diet in women. toxicol. appl. pharmacol. 136: 332-334. 11ademorati cma (1996). environmental chemistry and toxicology. pollution by heavy metals. fludex press ibadan. pp. 171-172. 12igwe jc, iroh cu, abia aa (2005). removal of hg 2+ , pb 2+ and ni 2+ ions from wastewater using modified grammlar activated carbon (gac); adsorption and kinetic studies. j. environ. managt. (in press). 13igwe jc and abia aa (2006). a bioseparation process for removing heavy metals from wastewater using biosorbents. african journal of biotechnology vol. 5 (12), pp. 1167-1179. 14fu y, viraraghavan t. fungal (2001) decolourization of wastewaters: a review. bioresour technol; 79:251–62. 15robinson t, mcmullan g, marchant r, nigam p. (2001) remediation of dyes in textile effluent: a critical review on current treatment technologies with a proposed alternative. bioresour technol; 77:247–55. 16-sumathi s, manju bs. (2000) uptake of reactive textile dyes by aspergillus foetidus. enzyme microbial technol; 27:347–52. 17-o’mahony t, guibal e, tobin jm. (2002) reactive dye biosorption by rhizopus arrhizus biomass. enzyme microbial technol; 31:456–463. 18-fu y, viraraghavan t. (2002) removal of congo red from an aqueous solution by fungus aspergillus niger. advances environ res; 7:239–47. 19-zümriye aksu (2005) application of biosorption for the removal of organic pollutants: a review, process biochemistry 40 997–1026. 20-b. volesky, h.a. may-phillips, (1993) appl. microbiol. biotechnol. 42 797. 42 (1993) 797. 21-v. padmavathy (2008) biosorption of nickel(ii) ions by baker’s yeast: kinetic,thermodynamic and desorption studies bioresource technology 99 3100–3109 22y. sag, a. yalcuk, t. kutsal, (2001) use of a mathematical model for prediction of the performance of the simultaneous biosorption of cr vi and fe iii on rhizopus arrhizus in a semi-batch reactor, hydrometallurgy 59 77–87. 23margarita ramirez c. mˆonica pereira da silva, selma g. ferreira l., oscar vasco e. (2007) mathematical models applied to the cr(iii) and cr(vi) breakthrough curves, journal of hazardous materials 146 86–90 24padma vasudevan, v. padmavathy, s.c. dhingra (2003) kinetics of biosorption of cadmium on baker’s yeast, bioresource technology 89, 281–287. 25-belter pa, cussler el and hu ws, (1988) bioseparations, downstream processing for biotechnology, john wiley & sons, new york. 26-jos eph m brady, john m tobin, and jean-claude roux (1999) continuous fixed bed biosorption of cu2. ions: application of a simple two parameter mathematical abbas h. sulaymon, shahlaa e. ebrahim, tariq j. al-musawi, sama m. abdullah ijcpe vol.11 no.2 (june 2010) 13 model, journal of chemical technology and biotechnology, 74:71-77. 27lucas, s. and cocero, m. j., (2004) adsorption isotherms for ethylacetate and furfural on activated carbon from supercritical carbon dioxide. fluid phase equilibria, , 219, 171-179. 28weber, j. r. and walter, j., (1972) phtsicochemical processes for water quality control. wiley inter science, new york,. 29radke, c. j. and prausnitz, j. m., adsorption of organic compounds from dilute aqueous solution on activated carbon. ind(1972). eng. chem. funda.,, 11, 445-451. 30jossens, l., prausnitz, j. m. and frits, w., (1978) thermodynamic of multi-solute adsorption from dilute aqueous solutions. chem. eng. sci., 33, 1097-1106. 31sips, r., j. chem. phys., (1984), 16, 490-495. 32malkoc, e. and nuhoglu, y., (2006) fixed bed studies for the sorption of chromium (vi) onto tea factory waste. chemical engineering science, 61, 4363-4372. 33gupta, a., nanoti, o. and goswami, a. n.,( 2001)the removal of furfural from water by adsorption with polymeric resin, separation science and technology, , 36, 13, 2835-2844. 34lin, s. h. and wang, c. s., (2002)treatment of highstrength phenolic wastewater by a new two-step method, journal of hazardous materials, b90, pp 205-216. 35sulaymon, a. h., and ahmed, k. w., (2007) competitive adsorption of furfural and phenolic compounds onto activated carbon in fixed bed column, environ. sci. technol, 42,392-397. 36sulaymon, a. h., ali, a. m., and al-naseri, (2009) natural organic matter removal from tigris river water in baghdad, iraq, desalination, 245, 155-168. 37babu, b.v. and gupta, s. (2004) modeling and simulation for dynamics of packed bed adsorption. chem. conf., mumbai. 38sulaymon, a. h., balasim a. abid and jenan a. alnajar (2009) removal of lead, copper, chromium and cobalt ions onto granular activated carbon in batch and fixed bed adsorbers, chemical engineering journal, 155, 647-653. 1 iraqi journal of chemical and petroleum engineering vol.11 no.4 (december 2010)111 issn: 12010-4884 determination of the optimum operating conditions in the granulation of gamma alumina catalyst support alaa dhari jawad , ibrahim richeh , and ahmed saleh chemical engineering departmentcollege of chemical and petroleum engineeringal-baath universitysyria ________________________________________________________________ abstract granulation technique for gamma alumina catalyst support was employed in inclined disk granulator (idg), rotary drum granulator (rd) and extrusion – spheronization equipments .product with wide size range can be produced with only few parameters like rpm of equipment, ratio of binder and angle of inclination. the investigation was conducted for determination the optimum operating conditions in the three above different granulation equipments. results reveal that the optimum operating conditions to get maximum granulation occurred at ( speed: 31rpm , inclination:42 0 , binder ratio:225,300% ) for the idg,( speed: 68rpm , inclination: 12.5 0 , binder ratio: 300% ) for the rd and ( speed:1200rpm , time of rotation: 12min )for the caleva spheronizer used in the extrusion spheronization method. these results are compatible with similar works on granulation of different materials [1, 2, and 3]. keywords: spheronization, inclined disk granulator, rotary drum, extrusion – spheronization, gamma alumina, catalyst support, shaping of catalyst. ________________________________________________________________ introduction in chemical industry, alumina agglomrtates are often used as catalyst supports [4].the use of gamma al2o3 as a catalyst support requires a shaping operation adapted to the type of process: moving bed or fixed bed .for a moving bed, it is necessary to prepare 1 to 4mm diameter beads to facilitate circulation and iraqi journal of chemical and petroleum engineering university of baghdad college of engineering alaa dhari jawad, ibrahim richeh, and riad ahmed saleh 2 ijcpe vol.11 no.4 (september 2010) to limit the mechanical abrasion of the catalyst. for the fixed bed, the support can be in the form of either beads or cylindrical extrudate 1-4 mm in diameter. the catalyst support is shaped essentially by three methods: granulation, drop coagulation, and extrusion [5]. forming or shaping of supports and catalysts is an important step in the preparation procedure of a commercial catalyst. the catalyst must have a prescribed shape and size for the given chemical reactor. the shape and size is determined by the application of the catalyst and the type of the reactor in which it will be used. for a fixed bed reactor it is very important that the pressure drop over the bed is as low as possible. this condition is usually fulfilled by using pellets, extrudate or spheres with a diameter greater than 3 mm. [6, 7]. granulation is the generic term used for particle agglomeration processes, in which fine powdery solids are agglomerated together with a liquid /melt binder to form larger aggregates. depending on the process requirements, a rotating drum, fluidized bed or high shear mixer granulator may be used for granulation by agitation [8].this paper is concerened with granulation in inclined disk granulator, rotary drum granulator and extrusion – spheronizaton equipments. drum granulation is a particle size enlargement process often obtained by spraying a liquid binder or slurry onto fine particles as they are agitated in a rotary drum. a typical continuous granulation circuit consisting of a drum granulator, rotary dryer ,screen classifier, crusher and a number of conveyors [9]. extrusion and spheronization is currently one of the techniques used to produce pharmaceutical pellets. the preparation of spherical granules or pellets by extrusion and spheronization is now a more established method because of its advantages over the other methods [10, 11]. in principle the basic machine consists of a round disc with rotating drive shaft, spinning at high speed at the bottom of a cylindrical bowl. the spinning friction plate has a carefully designed groove pattern to the base. this is most often crosshatched, but several sizes and other types are available. these discs are designed to increase the friction with the product [12]. as processing continues the shape of the pieces gradually changes as shown ion fig. 2 below [12]. when the particles have reached the desired shape then spheroids can be removed. disk granulators it consists of a tilted rotating disc with a rim to hold the tumbling granules. powder feed are continuously fed to the disc, typically at the edge of the rotating granular bed. liquid binder is added through a series of single fluid nozzles distributed across the face of the bed. the critical speed is speed at which a granule is just held stationery on the rim of the disc by centripetal forces alone. no= (g sin β/2π 2 d) 1/2 1-1 discs are typically operated at between 50 and 75% of critical speed with the angle between 45 and 55 0 .if the speed is too low, the particle mass will slide determination of the optimum operating conditions in the granulation of gamma alumina catalyst support 3 ijcpe vol.11 no.4 (september 2010) against the disc instead of tumbling [3, 14]. the purpose of this work is to determine the optimum operating conditions in the granulation (spheronization) of the gamma alumina catalyst support by using three spheronization methods( inclined disk granulator, rotary drum and extrusion – spheronization) . experimental work materials gamma alumina powder supplied suzhou yuguang lighting materials co. ltd. from china was used with the properties shown in table 1 .the xrd chart for it is shown in fig. 1. table 1 properties of the gamma alumina powder no. specification value 1 name high purity alumina powder 2 type gamma-al2o3 3 purity% 99.99 4 particle size,µm 0.2 5 loose density, g/cm 3 0.16 6 bet,m 2 /g 120 7 k,ppm 30 8 na,ppm 18 9 fe,ppm 10 10 si,ppm 20 11 mg,ppm 10 12 mn,ppm 9 13 ti,ppm 10 14 cr,ppm 10 15 cr,ppm 10 16 zn,ppm 10 figure 1 xrd chart for the gamma alumina powder used commercial sodium silicate solution was used as a binder, its specific gravity is 1.500 and its concentration is 44%, and used widely in detergent industries in syria. equipments inclined disk granulator (pan granulator) in our work, an equipment was designed to fix pan granulator of dimension, d: 27cm, height of the wall of the pan (h):5 cm .the equipment was provided with invertor (delta 0.75hp) to supply variable speed (0300 rpm) ,also it is provided with facility to make inclination angle in the range of (0-90 0 ), the motor is of type ( 50hz 230/400v /y,0.25kw,1.71/0.99a , 1365 rpm). rotary drum granulator the rotary drum of diameter 17 cm, h: 14cm and has opening of d: 6cm was made and fixed on the same device designed for the idg described above. alaa dhari jawad, ibrahim richeh, and riad ahmed saleh 4 ijcpe vol.11 no.4 (september 2010) caleva spheronizer mbs a spheronizer device manufactured from caleva process solution ltd. company , uk, which has the capacity of loading 120gm extrudate for spheronization was used in the extrusion –spheronization method to get spheres of gamma alumina catalyst support. design of experiments the response surface method from the minitab 15 software was used to get the table of design for the determination of the optimum conditions in the granulation of gamma alumina powder in the idg and rd operation which include the affecting parameters (inclination angle, speed of rotation, binder ratio) [15] .the minimum and maximum limits for the above variables which was given to the minitab software were determined as shown in table 2. table 2 minimum and maximum values to the variables studied s variable devise min. max. 1 inclination angle idg rd 45 0 2 0 55 0 10 0 2 rotation speed idg rd 30 27 52 66 3 binder ratio% idg rd 150 150 225 225 the minimum and maximum speed for the idg were determined from us by calculating the critical speed of the disk used (d 27 cm) as shown in eq. 1and then operating in the range of 0.5-0.7nc , the minimum and maximum angle was determined according the information in the literature[14]. the minimum and maximum binder percentage were chosen according to reference [15] table 3 and table 4 shows the design of experiments to the above three parameters on the idg and rd operation to find the optimum conditions of operation to get the maximum granulation to the gamma alumina support spheres obtained. table 3 design of experiments to inclined disc granulator (idg) run 0rder inclination angle rpm binder percentage% 1 55 35 150 2 45 48 150 3 55 35 300 4 55 35 140 5 45 41 225 6 50 48 150 7 55 35 300 8 45 48 300 9 55 41 225 10 50 41 225 11 50 48 300 12 45 41 225 13 50 41 225 14 41 41 225 15 50 41 102 16 50 41 225 17 50 52 225 18 50 41 347 19 50 30 225 20 58 41 225 determination of the optimum operating conditions in the granulation of gamma alumina catalyst support 5 ijcpe vol.11 no.4 (september 2010) table 4 design of experiments to rotary drum granulator run 0rder inclination angle rpm binder percentage% 1 0.5 47 225 2 6 47 225 3 6 47 347 4 6 27 225 5 6 47 225 6 6 67 225 7 12 47 225 8 6 47 102 9 6 47 225 10 6 47 225 11 2 60 150 12 2 35 150 13 10 60 300 14 10 60 150 15 6 47 225 16 10 35 300 17 2 35 300 18 6 47 225 19 10 35 150 20 2 60 300 the binder was diluted with 2 parts of distilled water and sprayed by the spray bottle. the basis for calculation the percentage of binder ratio in each batch is 20 gm of gamma alumina powder of the specifications shown above in the materials paragraph. scraper was used by hand to scrap the powder from the surface of the idg and rd .spheres was collected from the idg and the rd and then sieved to 2 and 3 mm using the astm standard sieves is due to the reforming catalysts specification. experiments were done to get the spheres of the gamma alumina catalyst support by the method of extrusion – spheronization method by using extrudate made by method of molding which composed of rubbing gamma alumina paste into the aperture of perforated steel plate. the size of granules produced is determined by the thickness of the plate and the diameter of the aperture [17].the extrudate of diameter 3mm was then loaded on the caleva spheronizer mbs at different speeds and time of rotation to get the optimum condition which give the maximum ( spheronization). the gamma alumina paste used for making extrudate was made by mixing gamma alumina powder with the sodium silicate binder in a quantity of 60%w/w based to gamma alumina powder used and then diluted the mixture with water of quantity equal the sum of the weight of both the gamma alumina powder and the sodium silicate solution used. the speed of mixing is 800 rpm, mixing continue until getting a paste having plasticity properties. results and discussion inclined disk granulator the optimum operating conditions found is as shown below: 1. fig. 2& 3 show that the best angle of inclination is about 42 0 for the total and the 2mm size granulation. 2. fig. 4 show the best angle of inclination to the granulation of 1mm gamma alumina is 50 0 . 3. fig. 5 & 6 show the optimum speed of rotation to get maximum total and 1 mm granules is around 31 rpm as shown in fig. 14 and 15. 4. 4. fig. 7 show the optimum speed of rotation to get 2 mm granules is 52rpm. alaa dhari jawad, ibrahim richeh, and riad ahmed saleh 6 ijcpe vol.11 no.4 (september 2010) 58.16555.00050.00045.00041.835 90 80 70 60 50 40 30 20 10 0 inclination angle m e a n o f % g r a n u l a t e d chart of mean( % granulated ) fig. 2 the total percentage granulated with respect to angle of inclination in idg. 58.16555.00050.00045.00041.835 60 50 40 30 20 10 0 inclination angle m e a n o f g m . g r a n u l e s o n 2 m m s ie v e chart of mean( gm. granules on 2 mm sieve ) fig. 3 the percentage 2mm granulated with respect to angle of inclination to idg. 58.16555.00050.00045.00041.835 8 7 6 5 4 3 2 1 0 inclination angle m e a n o f g m . g r a n u l e s o n 1 m m s i e v e chart of mean( gm. granules on 1mm sieve ) fig. 4 the percentage 1mm granulated with respect to angle of inclination to idg. 52.114548.000041.500035.000030.8855 90 80 70 60 50 40 30 20 10 0 rpm m e a n o f % g r a n u l a t e d chart of mean( % granulated ) fig. 5 the total granulated with respect to speed of rotation to idg. 52.114548.000041.500035.000030.8855 10 8 6 4 2 0 rpm m e a n o f g m . g r a n u l e s o n 1 m m s ie v e chart of mean( gm. granules on 1mm sieve ) fig. 6 percentage of 1mm granulated with respect to speed of rotation. 52.114548.000041.500035.000030.8855 50 40 30 20 10 0 rpm m e a n o f g m . g r a n u l e s o n 2 m m s i e v e chart of mean( gm. granules on 2 mm sieve ) fig.7 the relationship of rpm and percentage of 2mm granules obtained in idg. determination of the optimum operating conditions in the granulation of gamma alumina catalyst support 7 ijcpe vol.11 no.4 (september 2010) 5. fig. 8 and 9 show the optimum binder ratio of sodium silicate used to get total and 2mm granules is at 300% based on gamma alumina powder used. 347.475300.000225.000150.000102.525 80 70 60 50 40 30 20 10 0 binderpercentage m e a n o f % g r a n u l a t e d chart of mean( % granulated ) fig. 8the relationship between the binder percentage and percentage total granulation obtained in idg. 347.475300.000225.000150.000102.525 60 50 40 30 20 10 0 binderpercentage m e a n o f g m . g r a n u l e s o n 2 m m s ie v e chart of mean( gm. granules on 2 mm sieve ) fig. 9 the relationship between the binder percentage and percentage 2mm granules obtained in idg. 6. fig. 10 show the optimum binder percentage to get the 1mm granules is at 225% 347.475300.000225.000150.000102.525 7 6 5 4 3 2 1 0 binderpercentage m e a n o f g m . g r a n u l e s o n 1 m m s ie v e chart of mean( gm. granules on 1mm sieve ) fig.10 the relationship between the binder percentage and percentage 1mm granules obtained in idg. rotary drum granulator 1. fig .11 show the optimum angle of inclination to get the total maximum granulation, it is 12.5 0. 12.53210.0006.0002.000-0.532 80 70 60 50 40 30 20 10 0 angle of inclination m e a n o f % g r a n u l a t e d chart of mean( % granulated ) fig.11 the relationship of angle of inclination to total granulation in the rd. 2.fig.12 show the optimum angle of inclination to get the maximum 2mm granules in rd granulator, it is 6 0 . alaa dhari jawad, ibrahim richeh, and riad ahmed saleh 8 ijcpe vol.11 no.4 (september 2010) 12.53210.0006.0002.000-0.532 40 30 20 10 0 angle of inclination m e a n o f g m . 2 m m s ie v e g r a n u l e s chart of mean( gm. 2mm sievegranules ) fig. 12 the relationship of angle of inclination to get the maximum 2mm granules in rd granulator 3. fig. 13show the optimum speed of rotation to get the maximum total granulation and 2mm granules in the rd granulator, it is 68 rpm. 67.912560.000047.500035.000027.0875 100 80 60 40 20 0 rpm m e a n o f % g r a n u l a t e d chart of mean( % granulated ) 67.912560.000047.500035.000027.0875 70 60 50 40 30 20 10 0 rpm m e a n o f g m . 2 m m s ie v e g r a n u l e s chart of mean( gm. 2mm sievegranules ) fig.13 the relationship of speed to total granulation in the rd. 3. fig. 14 show the optimum binder percentage to get the total rate of granulation in the rd granulator, it is 300%. 347.475300.000225.000150.000102.525 90 80 70 60 50 40 30 20 10 0 binder percentage m e a n o f % g r a n u l a t e d chart of mean( % granulated ) fig. 14 the relationship of binder percentage to get the maximum total granules in rd granulator caleva spheronizer fig. 24 shows at low speed of rotation (800 rpm) of the caleva spheronizer, the rate of spheronization of the gamma alumina extrudate increased with increasing the time of spheronization. the spheronization percentage will be decreased after definite time because of breaking the spheres formed. fig. 15 spheronization of gamma alumina extrudate in caleva spheronizer fig. 16 show high percentage of spheronization at speed of rotation of (1000 rpm & 1200rpm) and at low time (1 min.). 0 0.1 0.2 0.3 0.4 0 5 10 p e rc e n ta g e g ra n u la ti o n spheronization time-min speed 800rpm determination of the optimum operating conditions in the granulation of gamma alumina catalyst support 9 ijcpe vol.11 no.4 (september 2010) fig. 16 spheronization of gamma alumina extrudate at 1000rpm. fig. 17 show low percentage of spheronization at high speed of rotation 1400 rpm and increasing the time will decrease the percentage of spheronization more. fig. 17 rate of spheronization at 1400 rpm speed conclusions 1. the optimum operating conditions in the granulation (spheronization) of the gamma alumina catalyst support in the inclined disk granulator idg is: a. inclination angle :42 0 for the total and 2mm size granules , 50 0 for the granulation of 1mm.. b.speed of rotation: 31 rpm for the total and 1mm granulation, 52 rpm for the 2 mm granulation. c. binder percentage: 300% for the total and 2mm granulation, 225% for the 1mm granulation. note: the 300% binder percentage is really equal to 44% of pure sodium silcate , because the binder was diluted with 2 parts of distilled and its real concentration is 44% water as mentioned in the experimental work. similar works [8]mentioned that it is in excess of 55% volume (usually 59-73% volume ) for closely sized powders and between 40% and 55% volume for materials with wide size distributions .in practice ,however , the water content may range from roughly 90-110% of the critical liquid saturation. 2. the optimum operating conditions to the granulation of gamma alumina in the rotary granulators( rd) is: a. inclination angle: 6 0 for the granulation of gamma alumina of size 2mm, 12.5 0 for total granulation of gamma alumina catalyst support. b. speed of rotation: 68 rpm for total and 2mm granulation. 0 0.5 1 0 2 4 6 8 g ra n u la ti o n p e rc e n ta g e spheronization time speed 1000 rpm 0 0.5 1 0 5 10 granula tion percent age spheronization time speed 1200 rpm 0 0.05 0.1 0.15 0.2 0 2 4 granula tion % spheronization time speed 1400 rpm alaa dhari jawad, ibrahim richeh, and riad ahmed saleh 10 ijcpe vol.11 no.4 (september 2010) c.binder percentage:300% for total granulation .please refer to the note in paragraph 1 above. 3. the optimum operating conditions in the caleva spheronizer to get spheres of gamma alumina catalyst support is: a. speed of rotation: 1200 rpm .maximum spheronization rate (70%) obtained at 1200 rpm speed , while at 800 rpm , only 30% maximum spheronization obtained and only 60% maximum spheronization obtained for 1000rpm. b.time of spheronization: the minimum time of spheronization with maximum spheronization rate (1min.) was obtained at 1200 rpm and 1000 rpm ,while 5 min. time of spheronization obtained at 800rpm speed with maximum spheronization rate. references [1]irshad,u.,sharif,m.n,khan,r.u and rizivi,z.h. ,"granulation of urea in a pan granulator", journal of qualty and technology management.2010. [2]www.alibaba.com,disc pellitizer,disc granulator,pan granulator. [3]lister,jim , ennis , bryan, “the science and engineering of granulation processes”,kluwer academic publisher,netherland,2004. [4]d.f. wu,j.c. zhou and y.d.li,aiche j.,2007,53,26182629. [5]antos,george j., aitani, abdullah m., parea,jose m., " catalytic naphtha reforming science and technology", marcel dekker inc.,usa,1995. [6]van santen,r.a, vanleeuwen,p.w.n.m,moulijin,j. a. and averill,b.a,"catalysis:an integrated approach",elsevier,1993. [7]le page,j. f.,”applied heterogenous catalysis”, institute francais du petrole publications,france ,1987. [8]ramachandran, r., jonathan m.h., constantjin,f.w.thomas ,g. charles ,d. immanuel,francis,j.,lister,james d. and franisek stepanek," experimental studies on distrubitions of granular size, binder content and porosity in batch drum granulation:influences on process modeling requirements and process sensitivities",powder technology, 188(2008) 89-101. [9]wang,fu.y.,cameron,ian.t.,"r eview and future directions in the modeling and control of continuous drum granulation",powder technology 124(2002)238-253. [10]pstt (pharmaceutical science & technology today) vol. 2, no. 4 april 1999 [11]chatlapalli,r.,rohera,bhagwa n d., "physical characterization of hpmc and hec and investigation of their use as pellitization aids" international journal of pharmaceutics 161 (1998) 179–193 [12]caleva spheronizer mbs , installation & operation manual. [13]kapur,p.c.,"balling and granulation" in advances in chemical engineering http://www.alibaba.com,disc/ determination of the optimum operating conditions in the granulation of gamma alumina catalyst support 11 ijcpe vol.11 no.4 (september 2010) vol.10,academic press inc.,new york,1978. [14]montgometry,"design and analysis of experiments", john wiley & sons, 1997. [15]jawad,alaa dhari,richeh ,ibrahim, saleh,riad ahmed,"effect of the forming conditions in the production of gamma alumina catalyst support on the crushing strength property",ijcpe,11,2,june 2010 ,43-48. [16]mukhlyonov,i.p.,dobkina, e.i,deryuzhkina,v.i,soroko,v.e.," catalyst technology" ,mir publishers,moscow, 1976. ijcpe vol.10 no.2 (june 2009) iraqi journal of chemical and petroleum engineering vol.10 no.2 (june 2009) 35-42 issn: 1997-4884 lead removal from industrial wastewater by electrocoagulation process ibtehal k. shakir and besma i. husein chemical engineering department college of engineering university of baghdad – iraq abstract this investigation was carried out to study the treatment and recycling of wastewater in the battery industry for an effluent containing lead ion. the reuse of such effluent can only be made possible by appropriate treatment method such as electro coagulation. the electrochemical process, which uses a cell comprised aluminum electrode as anode and stainless steel electrode as cathode was applied to simulated wastewater containing lead ion in concentration 30 – 120 mg/l, at different operational conditions such as current density 0.4-1.2 ma/cm2, ph 6 -10 , and time 10 180 minute. the results showed that the best operating conditions for complete lead removal (100%) at maximum concentration 120 mg/l was found to be 1.2 ma/cm2 current density, in alkaline media ph = 10 , and at 120 minute. key wards; lead removal, electrocoagulation, and wastewater introduction the increased water use and wastewater discharge particularly industrial wastewater have added impurities to water which overload natural cleaning processes [1]. heavy metal species are some of the most common pollutants that are found in industrial wastewaters. because of their toxicity, these species can have a serious impact if released into their environment as a result of bioaccumulation, and they may be extremely toxic even in trace quantities. there are many problems associated with the presence of the trace metal in drinking water. metal ions such as cd2, pb+2 and hg+2 are serious health hazards, while zn+2, cu+2 are associated with taste and staining problems. due to pollution or natural cause, water sources exceed metal levees standards set by environmental protection agencies [2]. since growing populations result in significant increases in wastewater volume, there is an urgent need to develop innovative, effective and inexpensive technologies to treat wastewater. to address this problem, technologies such as ion exchange, ultrafiltration, reverse osmosis and chemical precipitation have been developed. each treatment method has advantages and disadvantages. ion exchange, for example, while highly effective in removal of certain charged contaminants, requires resin regeneration or replacement at a high cost. ultrafiltration and reverse osmosis are clean processes, but can be prohibitively expensive. while chemical precipitation is a simple process, it does generate a high volume of sludge. an effective technology that meets the requirements of process cleanliness, ease of manipulation, and low operational and investment costs is electro coagulation. this technology is essentially electrolytic processes that involve the destabilization of suspended, emulsified or dissolved pollutants in an aqueous medium, by the application of an electric current. in electro coagulation (a process similar to chemical coagulation), there is a reduction of the net surface charge to a point where the colloidal particles can approach closely enough for van der waal’s forces to hold them together and allow university of baghdad college of engineering iraqi journal of chemical and petroleum engineering lead removal from industrial wastewater by electrocoagulation process 2 ijcpe vol.10 no.2 (june 2009) aggregation to take place. the surface charge reduction is a consequence of the decrease of the repulsive potential of the electrical double layer by the presence of an electrolyte having an opposite charge. this mechanism corresponds to the destabilization of colloidal particles [3]. during electro coagulation, the coagulant is generated in situ by electrolytic oxidation of an anode of appropriate material. charged ionic species are removed from wastewater by allowing ions to react with oppositely charged ions, or with flocs of metallic hydroxides generated within the effluent [4]. in electro coagulation, sacrificial electrodes are used and the passage of an electric current through the water from electrodes causes the metal to go into solutions as ions via the anode reaction. a current is passed through a metal electrode, oxidizing the metal (m) to its cation (mn+) at the anode.   nemm n (1) simultaneously, water is reduced to hydrogen gas and the hydroxyl ion (oh-) at the cathode. 22 222 hoheoh   (2) electro coagulation thus introduces metal cations in situ, electrochemically, using sacrificial anodes, (usually aluminum or iron) inside a processing tank. the cation hydrolyzes in water forming a hydroxyl with the dominate species determined by solution ph. the metal ions combine with ohions from the water to from highly charged coagulation which adsorb pollutants form insoluble floc particles; so that al(iii) reacts with h2o to form al(oh)3. electro coagulation has proven its viability by removing a wide range of pollutants. the approach to reactor design has been haphazard, however, with little or no reference to previous designs or underlying principles [5]. 3 3 )(3 ohalohal   (3) electro coagulation cleans most wastewater streams better, with less operating cost, producing less sludge, with the sludge being a better quality than chemical precipitation. the reuse opportunities for the water is increased because dissolved solids are not added to the waste water stream, and usable products are harvested because the metal oxides pass leachability tests, allowing the sludge to be utilized as a soil additive [6]. vik et al. 1984 studied the efficacy of electrocoagulation in removal of humic acid from potable water [7]. renk,r.r., 1989, stated that electrocoagulation has reduced contaminated water volume by 98% and lowered the treatment cost by 90% for bilge water containing heavy metals and oil emulsions. although electrocoagulated water may vary because of the individual chemistry of process waters, a few examples of water treated by electrocoagulation include the reduction of heavy metals in water such as arsenic, cadmium, chromium, lead, nickel, and zinc are generally reduced by 95 to 99% [8]. naomi et al. 1993 concluded that alternating current electrocoagulation treatment achieved approximately 66% removal of lead in the high metals runs, where as polymer treatment showed a slightly higher removal (71%), while electrocoagulation treatment of slurries with low concentrations of metals yielded the highest lead removal (96%) [2]. rodnei et al. 1997 presented an electrolytic cell with a porous cathode of reticulated vitreous carbon (rvc) designed to remove metals from aqueous streams. the cell employed potential values in such away that the metals reduction reaction occurred under mass transport control, these potential are -0.3v for copper, -0.8v for lead and -1.35v for zinc, these applied to the cell from a potential mode, for two hours. the cell proved to be efficient in removing copper, zinc, and lead and it was able to reduce the levels of these metals from 50 mg/l to 0.1 mg/l [9]. chen et al. 2000 used electrocoagulation technology for the removal of suspended solids, oil and fat in restaurant wastewater [10]. escobar c. et al. 2006 optimized flow variables in the electro coagulation process to examine the effectiveness of the removal of copper, lead and cadmium. the electrochemical process, which uses electrodes of commercial laminate steel, was applied to simulated wastewater containing 12 mg dm-3 of copper, 4 mg dm-3 of lead and 4 mg dm-3 of cadmium. the optimum conditions for the process were identified as ph=7, flow rates 6.3 cm3 min-1 and current density between 31 and 54 a m-2, the copper removal reach a maximum value of 80% while reaching near 100% removal for lead and cadmium when the electrode distance was 2 cm [11]. ibtehal k. shakir and besma i. husein 3 ijcpe vol.10 no.2 (june 2009) amuda et al. 2006 studied the effectiveness of polymer addition to coagulation process during treatment of beverage industrial wastewater to remove some of its trace metals content such as lead, cadmium, iron, chromium, nickel, and zinc. experiments were conducted using the standard jar test procedure to determine the performance of both ferric chloride and organic polymer. the dosage used for ferric chloride ranged from 0 to 500 mg/l whereas polymer dosage varied between 0 to 100 mg/l. combination of 500 mg/l of ferric chloride and 65 mg/l for polymer achieved better removal efficiencies of the metals in the range of 84– 97 % [12]. samarghandi et al. 2007 used photo catalysis / hydrogen peroxide process for removal of phenol, lead and cadmium by three different ph of 3.5, 7 and 11, and variable concentrations of reagent chemicals, but the time was kept constant ( 180 min ). results indicated that the optimum efficiencies of phenol and cd removal were 76% and 97.7% at ph=11 respectively, and for lead it was 98.85 in all ph at uv irradiation with 3ml/l h2o2 and 0.8 g/l tio2 [13]. experimental work the object of this study is the evaluation of lead removal from industrial wastewater by electro coagulation process. for this study a glass tank 1.75 l volume was used . the cell comprised of two parallel plates (110 mm × 55 mm × 1 mm) with 30 mm distance between them and 70 cm2 used area. aluminum electrode as anode and stainless steel electrode as cathode, connected to the positive and negative poles of dc stabilized power supply (w.wrlenbach/schwiez model ic. triple). the electrical circuit was switched on as soon as the electrodes were immersed in the electrolyte and the desired current was achieved by altering the resistance of the electrical circuit. the schematic diagram of the system is shown in figure, 1. the standard solutions containing lead ions in different concentrations 30, 70, and 120 mg/l were prepared by dissolving lead nitrate pb(no3)2 in deionized water, 2-3 drops of nitric acid (hno3) must be added to the required amount of lead nitrate before adding the deionized water for complete mixing of lead nitrate with water. the experiments were conducted by introducing 1.5 liter of synthetic wastewater into the electrochemical reactor. by the passage of the electrical current through the cell, the anodic dissolution occurred. hydrogen gas was produced at the cathode along with localized pocket of the hydroxide ions and the cell will produce aluminum cation (al+3) on the anode surface followed by their transfer to the bulk of the electrolytic solution, these cation will combine with ohions from the water to form highly charged coagulants which adsorb pollutants to form insoluble floc particles, these particles will rise to the surface of solution by gas bubbles which formed in electrolytic solution. fig. 1 schematic diagram of the experimental apparatus during each run, samples of the solution were taken at different times (10, 20, 30, 60, 120 and 180) minutes, then this solution was filtrated to remove floc particles, then the filtrated solution taken to be analyzed by atomic absorption method (using perkin elmer 5000 atomic absorption spectrophotometer in the servicing laboratorychemistry dept.college of sciencesbaghdad university ), to measure the remaining concentration of lead ion in the treated solution. the percent of lead ion removal was measured at ph 6, 8 and 10 and in current density of 0.4, 0.8 and 1.2 ma/cm2. the ph values of the standard solution were measured using a digital ph meter ( oakton ph 2100 series ). while the current density was measured using digital multirange ammeter ( type: whn: 533638 ). results and discussion in the present study, electrocoagulation process has been evaluated as a treatment technology for lead removal from industrial effluents. lead removal efficiency at different condition (ph, current density) in various times was evaluated. it has been established in previous studies [7, 10] that ph has a considerable effect on the efficiency of the electrocoagulation process. in this study, the ph was varied in the range 6–10 in an attempt to investigate the influence of this parameter on the removal efficiencies of lead which shown is in figures 2-4. from these figures we can see that increasing ph of the solution will increase the removal efficiency of lead at power supply a + resistance box electrochemical reactor electrolytic solution anode cathode + lead removal from industrial wastewater by electrocoagulation process 4 ijcpe vol.10 no.2 (june 2009) constant current density. the same behavior can be achieved when changing the current density to other values. vik [7] ascribed this increase to hydrogen evolution at cathodes. however, this was contested by chen [10], who explained this increase by the release of co2 from wastewater owing to h2 bubble disturbance. indeed, at low ph, co2 is over saturated in wastewater and can release during h2 evolution, causing a ph increase. the highest efficiency of lead removal observed in alkaline medium and the best value ph =10. conc. =120 mg/l , i = 0.4 ma/cm^2 0 10 20 30 40 50 60 70 80 90 100 0 30 60 90 120 150 180 time , min. l e a d r e m o v a l % ph = 6 ph = 8 ph = 10 fig. 2 the between time of treatment and lead removal efficiency for different ph values at constant concentration 120 mg/l, constant current density 0.4 ma/cm2 conc. =120 mg/l , i = 0.8 ma/m^2 0 10 20 30 40 50 60 70 80 90 100 0 30 60 90 120 150 180 time , min. l e a d r e m o v a l % ph = 6 ph = 8 ph = 10 fig. 3 the between time of treatment and lead removal efficiency for different ph values at constant concentration 120 mg/l, constant current density 0.8 ma/cm2 conc.=120 mg/l , i = 1.2 ma/cm^2 0 10 20 30 40 50 60 70 80 90 100 0 30 60 90 120 150 180 time , min. l e a d r e m o v a l % ph = 6 ph= 8 ph = 10 fig. 4 the between time of treatment and lead removal efficiency for different ph values at constant concentration 120 mg/l, constant current density 1.2 ma/cm2 figures 2 – 4 show also the effect of changing time of reaction on the concentration of lead in the treated solution, when changing ph and current density at maximum concentration of lead 120 mg/l, due to aluminum dosage through the process. according to these figures, the lead removal efficiency will increase by increasing the time of process, especially there is a sharp increase at the first few minutes. this effect occurs due to adsorbing aluminum hydroxide which is formed in electrolytic solution to the contaminants in wastewater and also due to effect of current density on time. preliminary laboratory testing of the electrolysis cell involved determining the effect of applied current density on the efficiency of lead removal which is shown in figure 5. it is well-known that electrical current not only determines the coagulant dosage rate but also the bubble production rate and size and the flocs growth [14,15], which can influence the treatment efficiency of the electrocoagulation. therefore, the effect of current density on the pollutants removal was investigated. from figure 5 at ph=10 which is best value and at initial concentration 30mg/l where at low concentration the effect of current density can be noted clearly. as expected, it appears that for a given time, the removal efficiency increased significantly with increase of current density. the highest current density 1.2 ma/cm2 produced the quickest treatment reaching 93% lead removal after only 10 minute while for 0.4 ma/cm2 the removal efficiency for lead was only 50% and at 0.8 ma/cm2 89.7% removal after 10 minute. ibtehal k. shakir and besma i. husein 5 ijcpe vol.10 no.2 (june 2009) ph =10 , conc. = 30 0 10 20 30 40 50 60 70 80 90 100 0 30 60 90 120 150 180 time , min. l e a d r e m o v a l % i= 0.4 i= 0.8 i= 1.2 fig. 5 the between time of treatment and lead removal efficiency for different current density values at constant ph 10, and constant concentration 30 mg/l this is ascribed to the fact that at high current, the amount of aluminum oxidized increased, resulting in a greater amount of precipitate for the removal of pollutants. in addition, it was demonstrated that bubbles density increases and their size decreases with increasing current density, resulting in a greater upwards flux and a faster removal of pollutants and sludge flotation [16]. ph = 6 , i = 0.8 ma/cm^2 0 20 40 60 80 100 120 140 0 20 40 60 80 100 120 140 160 180 200 time , min. r e m a in in g l e a d c o n c ., m g /l conc.=30 conc.=70 conc.=120 fig. 6 the between time of treatment and remaining lead concentration for different lead initial concentration values at constant ph 6, and constant current density 0.8 ma/cm2 a set of experiments was performed with different initial concentrations of lead to determine the time required for removal under various conditions of electrocoagulation process. the results obtained at different current density showed that initial concentration of lead can effect on efficiency removal and for higher concentration of lead, higher current density or more reaction time is needed. on the other hand, if the initial concentration increases, the time required of process should increase too. and, also it is clear from figure 6 that the higher the concentration, is the greater the time needed for removal of lead, but that higher initial concentrations of lead were reduced significantly in relatively less time than lower concentrations. the time taken for reduction thus increases slowly with increases in concentration. so from figure 6 we can see that at ph=6 and current density 0.8 ma/cm2, the concentration of lead reduced from initial values of 30, 70 and 120mg/l to 28, 33 and 35 mg/l respectively after 20 minute only. this can be explained by the theory of dilute solution. in dilute solution, formation of the diffusion layer at the vicinity of the electrode causes a slower reaction rate, but in concentrated solution the diffusion layer has no effect on the rate of diffusion or migration of metal ions to the electrode surface [17]. according to figure 7, the results obtained at best conditions ( ph=10, and current density = 1.2 ma/cm2 ) showed that the removal efficiency for various concentrations of initial concentrations of lead (30,70 and 120) mg/l reach complete lead removal (100%) after 120 minutes almost. ph =10 , i = 1.2 ma/cm^2 0 10 20 30 40 50 60 70 80 90 100 0 30 60 90 120 150 180 time , min. l e a d r e m o v a l % conc.=30 conc.=70 conc.=120 fig. 7 the between time of treatment and lead removal efficiency for different lead initial concentration values at constant ph 10, and constant current density 1.2 ma/cm2 lead removal from industrial wastewater by electrocoagulation process 6 ijcpe vol.10 no.2 (june 2009) conclusions 1. electrocoagulation method followed by clarification was found to be highly efficient and relatively fast compared to conventional existing techniques. 2. by testing different values ph of synthetic wastewater. the highest efficiency of lead removal was in alkaline medium and best ph is 10. 3. the removal efficiency increased by increasing of current density and the best value is 1.2 ma/cm2. 4. complete lead removal (100%) can be achieved for various initial concentrations 30, 70 and 120 mg/l after 120 minutes only. references 1. gage, m.s., (1980), "industrial wastewater", epa-600/8-80-026, office of research and development, united state environmental protection agency. 2. naomi, p. barkley, clifton, farrell, and tracie, williams, (1993), "electro-pure alternating current electrocoagulation ", epa/540/s-93/504, united state environmental protection agency, sepetamper. 3. hiemenz p., rajagopalan, r. , (1997), "principle of collid and surface chemistry", marcel dek ker, new york. 4. mollah, y., schennach, r., parga, j., coocke, d. , (2001), "electrocoagulation (ec)-science and applications", journal of hazardous materials 84, 29-41. 5. holt, p. k., barton, g. w. and mitchell, c. a. , (1999), “electrocoagulation as a wastewater treatment”, department of chemical engineering, university of sydney, new south wales. 6. silverman, j. , (2007), "floc to the boogie electric", water and wastewater asia, march/ april , pp 52-53. 7. vik, e. a., carlson, d. a., eikum, a. s., gjessing, e. t. , (1984), "electrocoagulation of potable water", water res., 18 ,1355-1360. 8. renk, p.r.,(1989), "treatment of hazardous wastewaters by electrocoagulation ",,3rd annual conference proceedings . colorado hazardous waste management society. 9. rodnei, b., rosivania, c. w., marcos, r. v.l., rosana, a.d.i. and maria, f.b.s. , (1997), "electrolytic removal of metals using a flowthrough cell with a reticulated vitreous carbon cathode", journal barz. chem. soc., 8 (5), 487493. 10. chen, x., chen, g., po, l. y. , (2000), "separation of pollutants from restaurant wastewater by electrocoagulation", sep. purif. technol., 19, 65-76. 11. escobar, c., soto-salazar, c., toral, mi. ,(2006), "optimization of the electrocoagulation process for the removal of copper, lead and cadmium in natural waters and simulated wastewater", j. environ. manage., 81 (4), 38491, des.. 12. amuda,o.s.,amoo, i.a., ajayi, o.o., (2006), "coagulation / floccation process in the removal of trace metals present in industrial wastewater", j. appl. sci. enivon. mgt., septemper, vol. 10 (3), 159-162. 13. samarghandi m.r., nouri j., nasseri s., (2007), "efficiency removal of phenol, lead and cadmium by means of uv/tio2 /h2o2 process ", int. j. environ. sci. tech., 4 (1): 19-25. 14. letterman, r. d., amirtharajah, a., o'melia, c. r. , (1999), "a handbook of community water supplies", 5 ed.,awwa, mc graw-hill, n.y. usa. 15. hotl, p. h., barton, g. w., mitchell, a. a. , (2002), "a quantitative comparison between chemical dosing and electrocoagulation, colieds surf.", a: physicochem. eng. aspects., 211, 233-248. 16. khosla, n. k., venkachalam, s., sonrasundram, p. , (1991), "pulsed electrogeneration of bubbles for electroflotation", j. appl. electrochem., 21, 986-990. 17. chaudhary, a. j., goswami, n. c., grimes, s. m. , (2003), "electrolytic removal of hexavalent chromium from aqueous solutions", j. chem. technol. biotechnol.; 78, 877-883. ibtehal k. shakir and besma i. husein 7 ijcpe vol.10 no.2 (june 2009) ijcpe vol.11 no.1 (march 2010) 55 iraqi journal of chemical and petroleum engineering vol.11 no.1 (march 2010) 55-57 issn: 1997-4884 removal of dyes from polluted water by adsorption on maize cob ibtihage faisal chemical engineering department college of engineering university of baghdad – iraq abstract this research aimed to examine the effect of concentration of dyes stuff, contact time, temperature and ratio of adsorbent weight in (gm) to volume of solution in (ml) on the percentage removal. two dyes were used; direct blue 6 and direct yellow and the adsorbent was the maize cob. batch experiments were performed by contacting different weights of adsorbent with 50 ml of solution of desired concentration with continuous stirring at various temperatures. the percentage of removal was calculated and the maximum percentage of removal was 80%. and as the concentration of solution, contact time, temperature and the ratio of adsorbent to volume of solution increase the percentage of removal increase. introduction dyes are a large group of chemicals used in chemical industries especially in textile industry. dyes in use are so different compound and their environmental behavior is largely unknown (albanis, 2000). most of them are considered non –toxic, although some of them are not totally innocuous because they made of known carcinogens such as benzidine(klimiuk, 1999) . removal of dyes is difficult and poorly efficient upon the use of conventional physic-chemical and biological methods. usually, dyes containing sewage are treated by means of absorption, ozonization, membrane processes, coagulation with flocculation and biological processes (urszula, 2007). the process of adsorption is one of the most efficient methods for dye removal from sewage especially when the adsorbent is cheap and easily available (mahir, 1991). one of the effective techniques for removal of color from waste water is sorption by activated carbon. however, owing to expensive price of it, the use of activated carbon for removal of color is limited (james 1991). using agricultural by-products as adsorbents for the removal of pollutants such as dyes from waste solutions has been on the increase. this is because these agricultural by-products are naturally occurring; hence they are available at little or no cost. they also have advantages over the conventional adsorbent such as activated carbon particularly because of their low cost and high availability. there is also no need for complicated regeneration. one of these by-products is the maize cob (hema 2007). experimental work 1. the maize cob obtained was washed with water cut into small pieces, air dried, and crushed. 2. the sample of maize cob was washed again with distilled water to remove any contaminant that could affect the color measurement. 3. stock of solution of dyes (1000 ppm) were prepared by dissolving 1gm of each dye in a liter of distilled water and subsequently diluted with distilled water to the required concentration 500 ppm , 250 ppm, 125 ppm , 75 ppm , and 50 ppm . 4. step 3 was repeated for two dyes used for wool dying. the first was direct blue 6 and the second was direct yellow. the absorbency of each dye with the different concentration was measured using spectro university of baghdad college of engineering iraqi journal of chemical and petroleum engineering removal of dyes from polluted water by adsorption on maize cob 56 ijcpe vol.11 no.1 (march 2010) sc spectrophotometer using wave length suitable for each dye as shown in table 1. table 1:structure and the wave length at extinction measurement of the dyes examined. structure wave length, ג nm dyes 430 direct yellow c32h24n6o14s4 .na4 900 direct blue 6 there is approximately a linear relationship between the concentration of each dye and the absorbency so the concentration of each sample after treating with maize cob could be known by measuring the absorbency. 5. a 50 ml of each dye solution of known initial concentration was in contact with a required dose of maize cob. the sample was placed in a shaker and the absorbency after that was measured again. 6. the percentage removal was calculated by: percentage removal = (1) where ci = initial concentration ppm cf = final concentration ppm results and discussion effect of contact time the efficiency of adsorption of a dye from a solution was analyzed based on the changes in its concentration in the solution and the percentage of removal was calculated using equation (1). batch adsorption studies dyes were carried out by agitating in a shaker with rpm 75 min -1 50 gm of maize cob particles in 50 ml dyes solution with concentration 250 ppm at different periods of time (3 hr,4 hr, 6 hr ,8 hr, one day ).after adsorption , a liquot was separated by using a mesh with opening 125 µm to prevent any dust from maize cob to go with the liquot and the dye concentration was determined again . as shown in figure (1), as the contact time increases the percentage removal increases and for one day 80% of the dye was adsorbed. 0 10 20 30 40 50 60 70 80 90 0 5 10 15 20 25 30 contact time (hr) % r e m o v a l series1 series2 direct yellow direct blue 6concentration 250ppm temperature 30º c fig(1) effect of contact time on the percentage removal. effect of concentration the effect of concentration on the percentage removal was studied using 50 gm of maize cob with50 of dyes solution with different concentration for four hours at 30 ˚c and the results shown in figure (2). as the concentration increases the percentage removal increases for both types of dyes. 0 10 20 30 40 50 60 0 100 200 300 400 500 600 concentration (ppm) % r e m o v a l yellow blue 6 fig(2) effect of concentration on the percentage removal. effect of temperature increasing temperature has shown a less effect on the percentage of removal but also as the temperature increases the percentage of removal increases too as shown in figure (3). this was done by using magnetic stirrer with heater to reach different temperatures 25˚c , 30˚c, 35˚c and 40˚c during stirring 50 gm of maize cob with solutions with 250 ppm concentration . ibtihage faisal ijcpe vol.11 no.1 (march 2010) 57 0 10 20 30 40 50 0 10 20 30 40 50 te mpe rature ºc % r e m o v a l series1 series2 concentration 250ppm time 4 hrs direct blue 6 direct yellow fig(3) effect of temperature on the percentage removal. effect of ratio of adsorbent weight to volume of solution 0.25, 0.5, 1, 1.25, 1.5 ratio of weight of adsorbent in gm to volume of solution with 250 ppm concentration in ml was used and the contact time was four hours at 30˚c. the result was better to increase the ratio to have high percentage removal. this is shown in figure (4). 0 10 20 30 40 50 60 0 0.5 1 1.5 2 ratio o f adso rbent/ vo lume o f so lutio n % r e m o v a l series1 series2direct blue 6 direct yellow fig(4) effect of increasing ratio of weight of adsorbent(g) to volume of solution in (ml) on the percentage removal. conclusions the following conclusions were detected from the present investigations: 1. the removal of dye by adsorption on to agricultural by-product has been found to be useful means for controlling water pollution. 2. increases the ratio of adsorbent weight to the volume of solution show increasing in the percentage of removal. 3. temperature shows a less effect on the percentage of removal. references 1albanis , t.a ; hela , d.g ; sakellarides , t.m. removal of dyes from aqueous solution by adsorption on mixtures of fly ash and soil in batch and column techniques . global nest ; the int, j. vol 2 , no 3 , pp 237244 , 2000 2hema. m; arivoli . s. comparative study on the adsorption kinetics and thermodynamics of dyes on to acid activated low cost carbon. international journal of physical sciences vol.2 (1), pp.010-017, january, 2007 3james g , martin ; william . cobey . waste reduction, hand book for using a waste reduction approach to meet aquatic toxicity limits, 1991 4klimiuk , e; filipkowska , u ; korzeniowska , a . effects of ph and coagulant dosage on effectiveness of coagulation of reactive dyes from model waste water by polyaluminium chloride (pac). polish. jornal of environmental studies vol .8, no.2 (1999), 73-79 5mahir alkan ; mehmet dogan . removal of acid yellow 49 from aqueous solution by adsorption . fresenius environmental bulletin . volume 13-no 11 a. 2004 6urszula filipkowska. adsorption and desorption efficiency of black 8 and black 5 on to chitin and chitosan . polish chitin society , monograph xii, 2007 ijcpe vol.10 no.1 (2009) iraqi journal of chemical and petroleum engineering vol.10 no.1 (march 2009) 1-8 issn: 1997-4884 prediction of bubble size in bubble columns using artificial neural network nada sadoon ahmed zeki chemical engineering department college of engineering university of baghdad – iraq abstract in the literature, several correlations have been proposed for bubble size prediction in bubble columns. however these correlations fail to predict bubble diameter over a wide range of conditions. based on a dat a bank of around 230 measurements collected from the open literature, a correlation for bubble sizes in the homogenous region in bubble columns was derived using artificial neural network (ann) modeling. the bubble diameter was found to be a function of six parameters: gas velocity, column diameter, diameter of orifice, liquid density, liquid viscosity and liquid surface tension. statistical analysis showed that the proposed correlation has an average absolute relative error (aare) of 7.3 % and correlation coefficient of 92.2%. a comparison with selected correlations in the literature showed that the developed ann correlation noticeably improved the prediction of bubble sizes. the developed correlation also shows better prediction over a wide range of operation parameters in bubble columns. introduction the design and scale-up of bubble columns have gained considerable attention due to complex hydrodynamics and its influence on transport characteristics. although the construction of these columns is simple, accurate and successful design and scale-up require an improved understanding of multiphase fluid dynamics and its influences. the design and scaleup of bubble column reactors generally depend on the quantification of three main phenomena; (i) heat and mass transfer characteristics; (ii) mixing characteristics; (iii) chemical kinetics of the reacting system. thus the reported studies emphasize the requirement of the multiphase fluid dynamics and its influence on phase hold up, mixing and transport properties ( degaleesan et al 2001). scale –up problems basically stem from the scale dependency on the aforementioned phenomena. scale –up methods used in biotechnology and chemical industry range from know-how based methods that are in turn based on empirical guidelines, scale –up rules and dimensional analysis to know why based approaches that begin with regime analysis. this analysis is hydrodynamics ( deckwer and schumpe 1993). more specifically, in order to design bubble column reactors the following hydrodynamic parameters are required: specific gas-liquid interfacial area, axial dispersion coefficients of the gas and liquid , sauter mean bubble diameter, heat and mass transfer coefficient, gas hold up, physicochemical properties of the liquid medium. in order to estimate these design parameters for the system, experimental studies benefit from specialized measuring devices and accessories. the fluid dynamic characterization of bubble column reactors has a significant effect on their operation and performance. bubble populations, their hold up contributions and rise velocities have significant impact on altering the hydrodynamics, as well as heat and mass transfer coefficients. many literature correlations are proposed to predict sizes of bubbles and most important ones are presented in table (1). the average bubble size in a bubble column has been found to be affected by gas velocity, liquid properties, gas distribution, operating pressure and column diameter ( kantarci et al 2005). university of baghdad college of engineering iraqi journal of chemical and petroleum engineering prediction of bubble size in bubble columns using 2 ijcpe vol.10 no.1 (2009) since the early 80s, artificial neural networks (anns) have been used extensively in chemical engineering for such various applications as adaptive control, model based control, process monitoring, fault detection, dynamic modeling, and parameter (bhat and mcavoy 1990). ann provides a non-linear mapping between input and output variables and is also useful in providing crosscorrelation among these variables. the mapping is performed by the use of processing elements and connection weights. the neural network is a useful tool in rapid predictions such as steadystate or transient process flow sheet simulations. cai et al 1994 applied kohonen self-organizing neural networks to identify flow regimes in horizontal air-water flow. leib et al 1995 used a neural network model along with the mixed-cell model to predict slurry bubble column performance for the fischer-tropsch synthesis. piche et al 2001, and illuta et al 2002 used an ann to improve the prediction of various hydrodynamic parameter in packed bed and fluidized bed reactors .shaikh and aldahhan 2003, behkish et al 2005 used a back propagation neural network to predict the hold up bubble columns, while alhemiri and ahmedzeki 2008 used the same type of network to predict the heat transfer coefficient in bubble columns. building on these studies, the focus of this work is to develop a unified correlation for the bubble size prediction in the homogeneous region in bubble columns which can be useful for design engineers. this correlation is derived from the experimental data bank collected from the open literature. building ann anns are being applied to an increasing number of real world problems of considerable complexity. it is a massively parallel distributed processor that has a natural propensity for storing experimental knowledge and making it available. in the present work, a multilayer neural network has been used, as it is effective in finding complex nonlinear relationships. training was accomplished using neurosolutions by excel version 5, supplied by neurodimension, inc. copyright 1997-2005. mlp (multi-layer perceptron) is known as a supervised network because it requires a desired output in order to learn. the goal of this type of network is to create a model that correctly maps the input to the output using historical data so that the model can then be used to produce the output when the desired output is unknown. this type was used which is multilayered feedforward network (mlff), trained with static back propagation (bp) of error using the generalized delta rule [matlab, 2003]. bp was one of the first general techniques developed to train multi-layer networks, which does not have many of the inherent limitations of the earlier, single -layer neural nets. the bp algorithm is an iterative gradient algorithm designed to minimize the meansquared error between the desired output and the actual output for a particular input to the network [lendaris, 2004]. basically, bp learning consists of two passes through the different layers of the network: a forward pass and backward pass. during the forward pass the synaptic weights of the network are all fixed. during the backward pass, on the other hand, the synaptic weights are all adjusted in accordance with an error-correction rule [lippmann, 1987]. this algorithm may be found elsewhere [lendaris, 2004]. bp is easy to implement, and has been shown to produce relatively good results in many applications. it is capable of approximating arbitrary non-linear mappings. the success of bp methods very much depends on problem specific parameter settings and on the topology of the network [leonard 1990]. training a back-propagation network the steps for backpropagation training can be shown as follows (leonard, 1990): 1. initialize the weights with small, random values. 2. each input unit broadcasts its value to all of the hidden units. 3. each hidden unit sums its input signals and applies its activation function to compute its output signal. 4. each hidden unit sends its signal to the output units. 5. each output unit sums its input signals and applies its activation function ( hyperbolic tan in the present simulation)to compute its output signal. 6. each-output unit updates its weights and bias. development of ann based correlation database generation collecting of the data is the preliminary step for building ann. in this model 230 experimental data points ( for bubble diameter in the homogeneous region in bubble column) were collected from literature spanning the years (1956-2005). the source of data which is the past experimental work of different systems is given table (2). different geometries of bubble columns with various liquids (water, solutions of ethanol, buthanol, naoh, and glycerol), were included in the data bank. the input parameters to the network were selected from the most important parameters affecting bubble diameter. therefore, six parameters were chosen as the input layer given in table (3) with the range taken for each. the output to the network ( the desired parameter) is the bubble diameter for bubbles in the homogeneous region. nada sadoon ahmed zeki 3 ijcpe vol.10 no.1 (2009) ann design training was accomplished using neurosolutions by excel version 5, from neurodimension, inc. copyright 1997-2005. multilayered feedforward network. type was used and trained with static backpropagation of error. 75% of the collected data (230) was set for training and the rest is for testing. the ann topology consists of three layers; the first is the input layer with six neurons ( pes) representing the six aforementioned parameters. the second consists of one or two hidden layers which is the varying part in this work , each with different number of neurons. the selection of the number of hidden layers and the number of neurons (perceptrons or pes )in each hidden layer is the target for such research and it is troublesome. for the purpose of finding the best architecture of the network, the testing mse, %aare and the correlation coefficient (%r) which should be around unity, are calculated and compared for each topology and for each type of ann. testing is made for the 25% part of the collected data which are not seen by the network the size of the mean square error (mse) can be used to determine how well the network output fits the desired output, but it doesn't necessarily reflect whether the two sets of data move in the same direction. for instance, by simply scaling the network output, we can change the mse without changing the directionality of the data. the correlation coefficient (r) solves this problem. by comparing the results of ann models, which have different number of pes in each hidden layer, the optimal ann structure has been obtained. all trials were made initially using a hyperbolic tangent (tanh) activation function, constant momentum rate (the acceleration parameter used to improve convergence) of 0.7 and 5000 number of iterations (how many times the network sees the whole data). results and discussion (i) one hidden layer first trials were made using one hidden layer. the number of processing elements were changed using constant parameters of activation function of (tanh), momentum rate of (0.7) and 5000 iterations. results for selected ann structures of one hidden layer are listed for comparison in table (4). the number of processing elements in the hidden layer was plotted against mse, correlation coefficient and %aare. these relations are shown in figures 1,2 and 3. (ii) two hidden layers in order to find a better performance of the network, many topologies of two hidden layers were also examined. different numbers of processing elements in each layer were applied and the results of mse, %aare and correlation coefficient were compared. some selected structures are listed for comparison in table (5). by examining table (5), it would be obvious that the performance of ann structure using two hidden layers is improved in comparison with one hidden layer. the structure of [6-12-12-1] is found the best. further investigation was made for the optimum ann structure of [6-12-12-1] by changing the momentum rate. it was found that the momentum rate of 0.7 ( by default) still gave the best performance for aan model. results are given in table (6). the numbers of processing elements in the second hidden layer were varied to see the effect on the performance of the network. results given in table (7), showed that [612-12-1] is the best structure among others. therefore, after careful training of the network, testing showed that ann structure of [6-12-12-1] using the activation function of (tanh), momentum rate of 0.7 and after 5000 iterations, had correlated the bubble diameter in the homogenous region in bubble columns successfully. the result of prediction is plotted with experimental values as shown in figs (4) and (5). statistical analysis based on the test data is calculated to validate the accuracy of the output for pervious correlation model based on ann. the structure for each model should give the best output prediction, which is checked by using statistical analysis. results are given in table (8). the proposed model of ann was compared with literature correlations. these correlations showed poor agreement between the prediction and experimental bubble diameter values. results are given in table (9) and its graphical representation is shown in fig (6). the problem facing ordinary correlation (when used for reproducing other experimental data) is that it is restricted to their systems and range of variables studied, leading to high percentage of error. artificial neural network had proved that it is powerful tool in solving complex non-linear relationships when ordinary correlations fail to simulate experimental data. prediction of bubble size in bubble columns using 4 ijcpe vol.10 no.1 (2009) table 1 correlations for bubble size (kantarci et al 2005) researcher correlation miller (1974) 3/1 )( 6         glg d d ob   moo-young and blanch (1981) 32.048.0 re19.0 oob dd  leibson et al (1956) 3/12/1 re18.0 oob dd  kumar and kuloor (1970) 4/33/1 2 15 3 4                lg q vb   bhavaraju et al (1978) 21.0 2 21.0 4 23.3                   gd q d q d d ooo b   table 2 database references. no. researcher(s) system 1 van den hangel (2005) air-water, dt=0.052m, 0.02m. 2 mews and wiemann (2004) air-water , dt=0.15m, perforated plate. 3 hillmer (1993) dt=0.15m, do=0.003m, 4 shah et al (1985) air-water and different concentrations of aqueous ethanol , dt=0.1m, do=0.001m. 5 miayhara (1983) air-water, dt=0.05m, perforated plate. 6 kumar et al (1976) air-water, kerosene, aqueous glycerol and 2n naoh, dt=0.01m,single orifice do=0.00153m and perforated plate. 7 koide et al (1966) air-water, (53and 80% by vol.) glycerin dt =0.15m, perforated plate. 8 towell et al (1965) air-water, dt= 0.406m ,perforated plate. 9 tadakiet (1963) dt =0.01m, do=0.001m 10 leibson et al (1956) air-water and aqueous butanol, dt=0.2m, do=(0.0016-0.003)m. 11 van krevelen and hoftijzer(1950) air-water, dt= (0.02-0.06m), single orifice of different sizes. table 3 range of the input parameters in p u t parameter range superficial velocity 0.000120.01995 m/s orifice diameter 0.000419 – 0.02m column diameter 0.026-0.2 m liquid density 787.2-1211 kg/m 3 liquid viscosity 0.00088-0.035 pa.s liquid surface tension 0.07450.0072 n m output bubble diameter 0.00204 -0.00925 m table 4 different ann structures using one hidden layer. case ann structure mse %aare %r 1 6-4-1 * 5.22 x 10 -7 12 75.8 2 6-8-1 6.35 x 10 -7 13.8 73.6 3 6-10-1 6.3 x 10 -7 13.1 73 4 6-12-1 5.19 x 10 -7 11.78 77 5 6-14-1 6.88 x 10 -7 13.9 71 6 6-16-1 7.38 x 10 -7 14.48 69.6 7 6-20-1 6.7 x 10 -7 13.4 70 * refers to the number of neurons in the [inputhiddenoutput] layer table 5 ann structure using two hidden layers. table 6 different momentum rates for the [6-12-12-1] ann model momentum mse %aare %r 0.5 3.29e-7 9.2 88 0.7 2.2e-7 7.3 92.2 0.8 3.03e-7 8.68 89 1.0 3.77e-7 9.88 86.5 case ann structure mse %aare %r 1 6-4-4-1 3.58e-7 10.8 86.8 2 6-8-8-1 2.6e-7 8.8 90.6 3 6-10-10-1 2.69e-7 8 90.3 4 6-12-12-1 2.2e-7 7.3 92.2 5 6-15-15-1 3.1e-7 9.1 88.7 6 6-25-25-1 3.55e-7 8.7 87 nada sadoon ahmed zeki 5 ijcpe vol.10 no.1 (2009) table 7 ann structure with different pes in the second hidden layer. case ann structure mse %aare %r 1 6-12-4-1 2.65e-7 8.86 90.7 2 6-12-8-1 3.79e-7 8.7 86 3 6-12-12-1 2.2e-7 7.3 92.2 4 6-12-16-1 3.3e-7 9.03 88 5 6-12-20-1 3.3e-7 8.02 87.9 table 8 statistical analysis for the proposed model. performance db mse 2.20721e-07 nmse 0.151403968 mae 0.000343427 min abs error 9.19866e-06 max abs error 0.001536108 r 0.92209016 table 9 comparison the present results with previous work correlation aare% %r miller(1974) 37 13.4 moo-young and blanch(1981) 51 20 bhavaraju et al (1978) 79 30 ann(present study) 7.3 92.2 0.0000002 0.0000003 0.0000004 0.0000005 0.0000006 0.0000007 0.0000008 0 5 10 15 20 25 no. pes i n h i dde n l aye r m s e fig.1 mse vs. no. of processing elements in hidden layer. 10 12 14 16 0 5 10 15 20 25 no. pes i n h i dde n l aye r % a a r e fig.2 %aare vs. no. of processing elements in hidden layer. 68 70 72 74 76 78 80 0 5 10 15 20 25 no. pes i n h i dde n l aye r % r fig.3 % r vs. no. of processing elements in hidden layer. desired output and actual network output 0 0.001 0.002 0.003 0.004 0.005 0.006 0.007 0.008 0.009 0.01 1 6 11 16 21 26 31 36 41 46 51 56 exemplar o u tp u t db db out put fig.4 desired (measured) and the actual (predicted) values vs. testing exemplars. prediction of bubble size in bubble columns using 6 ijcpe vol.10 no.1 (2009) y = 0.9786x 0 0.002 0.004 0.006 0.008 0.01 0 0.002 0.004 0.006 0.008 0.01 me as ure d bubble diame te r(m) p r e d ic te d b u b b le d ia m e te r (m ) fig.5 predicted bubble diameter versus desired values for ann structure of [6-12-12-1] 0 0.005 0.01 0 0.005 0.01 measure bubble size(m) p r e d ic te d b u b b le s iz e (m ) series1 series2 series3 series4 series5 linear (series5) miller 74 moo-young 81 bhavaraju ann this work fig.6 the predicted values by ann with previous work. conclusions from the present study of using ann in predicting the bubble size in the homogenous region in bubble columns. it is concluded that ann structure of [6-12-12-1] was chosen as the best to implement the target of the present study. mlp architecture of six inputs in the first layer (gas velocity, column diameter, diameter of orifice, liquid density, liquid viscosity and liquid surface tension) with 12 pes in the 1 st hidden layer and 12 pes in the 2 nd hidden layer, and one output in the third layer which is the desired output of bubble size. momentum rule was 0.7, hyperbolic tan activation function, and 5000 numbers of iterations were used. ann predicted well the diameter of bubbles which is better than those, obtained for the selected literature correlations; it yielded a minimum aare of %7.3 and a correlation coefficient of 92.2%. nomencalature aare: average absolute relative error.    n erimental x erimental x prediction x n aare 1 exp exp1 where: n, here, is the number of data points. x is bubble diameter. bp : back propagation. mae : mean absolute error. max abs error : maximum absolute error. min abs error : minimum absolute error. mlff : multilayered feedforward network. mlps : multi-layer perceptron. ann : artificial neural network. d b : diameter of bubble(m). mse : mean square error mse = ])([ 2 1 2p k p k p k od p  where p is the number of patterns in training set k is the number of iterations. p k d is the desired output. p k o is the actual output. nmse : normalized mean square error defined as:         p j n i n i ijij n ddn msepn nmse 0 0 0 22 )( where p=no. output pes n=no. exemplars in the data set mse= mean square error. dij= desired output for exemplar i at pes j. pes : processing elements (neurons). r : the correlation coefficient 2) 1 (2)exp 1 exp ( ) )( )(exp 1 )(exp (       n i predictionx prediction xerimentalx n i erimental x predictionx iprediction xerimentalx n i ierimental x r x experimental: bubble diameter mean of experimental points. x prediction : bubble diameter mean for prediction points. nada sadoon ahmed zeki 7 ijcpe vol.10 no.1 (2009) references 1. akhtar a., pareek v., and tad´e m., 2007 “cfd simulations for continuous flow of bubbles through gas-liquid columns: application of vof method” chemical product and process modeling vol. 2, iss. 1, art. 9. 2. al-hemiri a., and ahmedzeki n., 2008 “ prediction of heat transfer coefficient in bubble columns using an artificial neural network” international j. chem. reactor >eng.,vol.,6, a72. 3. bahavraju,s.m., .w.f.russel , and h.w. blanch, 1978, “ the design of gas sparged devices for viscous liquid systems” aiche j., 24, 454. (cited in kantarci et al 2005). 4. behkish a.,et al ,2005, “ prediction of the gas holdup in industrial-scale bubble columns and slurry bubble column reactors using backpropagation neural networks, j.int.chem.eng.vol.3. 5. bhat n., and mcavoy t.j.,1990 “ use of neural nets for dynamic modeling and control of chemical process system”computer chem.eng. vol.14,no.4/5,pp.573-583. 6. cai sh., toral h., qiu j., archer j.s., 1994, “network based objective flow regime identification in air-water system two phase flow”, can.j.chem.eng.,vol. 72, june. 7. deckwer wd., and schumpe a., 1993 “improved tools for bubble column reactor design and scale up” chem. eng. sci.48, 889911. 8. degaleesan, s.,m. dudukovic andy.pan,2001"experimental study of gas induced liquid-flow structures in bubble columns," aiche j., vol. 47, no. 9, pp.19131931. (cited in akhtar 2007) 9. hillmer g., 1993, phd thesis ,university erlangen-nurnberg. 10. illuta i., grandjean and larrachi f., 2002 “ hydrodynamics of trickle –flow reactors: updated slip functions for the slit models” chem. eng. res.des. 80, (a2),195. 11. kantarci, n., borak, f., ulgen, k.o.,2005, “bubble column reactors.” process biochem. 40, 2263-2283. 12. koide k., hirahara t., and kubota h., 1966, kagaku kogaku 30, p. 712. 13. kumar a.,and degaleesan t., la ddhacs, and h., hoeischer,1976, “ bubble swarm characterstics” cand. j. chem. eng. vol.54. 14. kumar r., kuloor nr. 1970 “ the formation of bubbles and drops” adv. chem. eng., 8, 256368. 15. leibson i., halcomb eg., cacosco ag and jamic jj., 1956 “ rate of flow and mechanisms of bubble formation from single submerged orifices. aiche j., 2(3),296. 16. lendaris, g., (2004) “supervised learning in ann from introduction to artificial intelligence”, new york, april 7. 17. leonard, j., and kramer, m.a., (1990) “improvement of the back-propagation algorithm for training neural networks”, comp. chem. eng, 14, 337-341. 18. lippmann, r.p., (1987) “an introduction to computing with neural nets”, ieee magazine, april, pp.4-22. 19. matlab, version 7, june 2003, “neural network toolbox” 20. mewes d., and wiemann d.,2004, “ two phase flow with mass transfer in bubble columns” chem. eng. tech. 26,pp.862-868. 21. miayhara t., matsuba y., and takahashi.,1983 “ the size of bubbles generated from perforated plates” international chem. eng. j., vol. 23, no.3. 22. miller dn., 1974 “ scale up of agitated vessels gas-liquid mass transfer.” aiche j., 20,445. 23. moo-young m., and blanch hw.,1981 “ design of biochemical reactors” adv.biochem. eng. 19,1-69. 24. piche, s.,larachi f., and grandjean a., 2001 “improved liquid hold up correlation for randomly packed towers” chem. eng. res.des. 79,(a1),71.(cited in shaikh and al-dahhan 2003). 25. shah y.t., joseph, s., smith, d.n., ruether, j.a., 1985,“two-bubble class model for churnturbulent bubble-column reactor,” industrial & engineering chemistry process design and development, vol. 24, pp. 10961104. 26. shaikh, a., al-dahhan, m., 2003,“development of an artificial neural network correlation for prediction of overall gas holdup in bubble column reactors”, chemical engineering and processing, vol. 42, pp. 599-610. 27. towell g., strand b., and ackerman,gh., aiche i. chem.e. sump. ser.no. 10,97. 28. van den hangel e. i.v., deen n.g., and kuipers j.a.m., 2005, “application of coalescence and breakup models in a discrete bubble model for bubble columns” ind.chem.eng.res.,44, pp.5233-5245. prediction of bubble size in bubble columns using 8 ijcpe vol.10 no.1 (2009) 29. van krevelen dw.,and hoftijzer p., 1950, chem.eng. prog., 46, 29. 30. tadakiet t., and maeda s., 1963 ,kagaku kogaku, 27, p. 402. (cited in miayhara !983). 31. towell g.d., strand b s., and ackerman gh., 1965, aiche., i. chem., symp.ser. no.10,97. فٍ االبزاج انفقاػُت َاسخؼمالاثنخىبؤ بقطز انفقاعا انذكُتصطىاػُت انشبكت اال . انؼزاق/ بغذاد / قسم انهىذست انكُمُاوَت / جامؼت بغذاد كهُت انهىذست / وذي سؼذون احمذ سكٍ : الخالصة َىجذ فٍ االدبُاث انمىشىرة ػذد مه انمىدَالث انزَاضُت انخٍ حسخؼمم نهخىبؤ بقطز انفقاػاث فٍ ػمىد انفقاػاث ونكه حفشم ( 230بحذود ) مه انمؼهىماث ونهذا وباالسخىاد انً ػذد. نظزوف انمخخهفتاهذي انمىدَالث ػىذ حطبُقها نمذي واسغ مه جمؼج مه االدبُاث انمىشىرة، حم انحصىل ػهً مىدَم نقطز انفقاػت فٍ انمىطقت انمخجاوست نهبزج انفقاػٍ باسخؼمال انشبكت حم اوخخاب مجمىػت ػىامم مؤثزة وحم حصىُفها انً سخت مجامُغ نغزض اسخؼمانها كمذخالث انً . االصطىاػُت انذكُت . سزػت انغاس وقطز انؼمىد وقطز انثقىب وكثافت انسائم ونشوجت انسائم وانشذ انسطحٍ نهسائم: هذي انؼىامم هٍ . انشبكت نقذ حم انمقاروت مغ %. 92.2 ومؼامم ارحباط 7.3 حساوٌ aare%نقذ اثبج انخحهُم االحصائٍ ان نهمىدَم وسبت انخطا فٍ انخبؤء بقطز انفقاػاث نمذي واسغ مه انظزوف ann مىدَالث مىخخبت فٍ االدبُاث وحبُه بىضىح وجاح شبكت ال .انخشغبهُت iraqi journal of chemical and petroleum engineering vol.17 no.4 (december 2016) 8394 issn: 1997-4884 investigation of binary solvents performance for regeneration of iraqi 15w40 waste lubricant hussein qasim hussein and ali laith abdulkarim chemical engineering department college of engineering university of baghdad abstract the aim of this study was to investigate the effectiveness of binary solvent for regeneration of spent lubricating oil by extraction-flocculation process. the regeneration was investigated by bench scale experiments by using locally provided solvents (heavy naphtha, n-butanol, and iso-butanol). solvents to used oil, mixing time, mixing speed and temperatures were studied as operating parameters. the performance on three estimated depended key parameters, namely the percentage of base oil recovered (yield), percent of oil loss (pol), and the percent of sludge removal (psr) were used to evaluate the efficiency of the employed binary solvent on extraction process. the best solvent to solvent ratio for binary system were 30:70 for heavy naphtha : n-butanol (n:n-but) and heavy naphtha : iso-butanol (n:iso-but). the optimum solvent to oil ratio or critical clarifying ratio (ccr) were 3.4, and 3.8 for n : n-but, and n : iso-but respectively. the optimized operating mixing time, mixing speed, and temperature which result in, maximum recovered base oil (87.75% and 88.88%), minimum oil losses (8.46% and 3.62%), and maximum sludge removal (5.63% and 6.12%), were (45 min, 700 rpm, 35 o c), and (30 min, 700 rpm, 35 o c ) for n:n-but, and n:iso-but respectively. key words: extraction-flocculation, used oil regeneration, pol, psr. introduction increasing of energy demand associated with increasing the consumption of lubricants, as a result larger amount of used oil produced yearly, and disposal issues raised up [1]. lubricating oil have to be replaced after served the designated period because chemical turn out along with contaminants accumulation. lubricating oil considered a highly pollutant agent because it included a percentage of polycyclic aromatic hydrocarbons (pahs) beside heavy metals (zn, pb, fe), which made it harmful to environment [2, 3]. after purification, used oil can be used as a fuel, the alternative way of disposal is to recover the base oil from used oil, which seemed more environmental and economic than used the first way, where the amount of used oil required to produce a certain amount of base oil is 9 times less than the that of crude oil required to produce the same amount of base oil [4]. solvent extraction treatment method of used oil preferred over another treatment methods because it solved, the problem such as acidic university of baghdad college of engineering iraqi journal of chemical and petroleum engineering investigation of binary solvents performance for regeneration of iraqi 15w40 waste lubricant 84 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net sludge produced which is difficult to disposal, highly metal content of recovered base oil, and high cost due to the required quantity of clay associate with using the eldest treatment acid-clay, which is out of use in developing countries [5]; solved the problems of high cost and loss of oil associated with vacuum distillation-extraction process [6]; also solved the problems associated with using distillation-hydrogenation process such as the difficult hydrogenation step, due to the nature of hertoatoms (h, n, s), possibility of forming potential pollutant dissolved stable beside gaseous compounds, and the cost of catalyst [7, 8]. solvent extraction process associated with mixing the used oil with suitable solvent at appropriate ratio to recover the base oil and segregate the impurities. the employed solvent is recoverable and usually suitable to be employed in another process [9]. the action of flocculation depends on the characteristics of the particles as well as the fluid-mixing conditions; flocculation of dispersed solid impurities occurring due to destabilization of these impurities. by mixing the destabilized solid contaminants and due to random brownian motion as well as velocity gradient of these particles flocculation occurred [10, 11]. the chemical composition of used oil is varied and difficult to characterize due to the various service period, and the type and concentration of additives [12]. for this reason using a composite solvent system were applied to eliminate as could as possible of used oil contaminants. many attempts used a composite solvent in used oil treatment such as, martins (1997), used a ternary solvent composite of butanol/ isopropanol / nhexane [13], durrani et al. (2011), were they used binary system of solvent composite of two alcohols (isopropanol/butanol) and ketone (mek) [14], and mahmood (2015), used a binary system composite of acetone /mek and acetone/heptane [15]. the main goals of this issue are: suggest an effective binary solvents which result in a good refining of the recovered base oil from iraqi used lubricant (al-durra 15w-40), determine the critical clarifying ratio (ccr) of solvent to used oil, and investigate the effect of various operating conditions at the ccr on the process key parameters. experimental work 1. materials 1.1. used oils al-duraa (15w-40) used lubricating oil. in order to ensure that the used oil is came from iraqi crude oil, virgin lubricants were employed in automobile at different operating conditions (1500, 2000, and 2500 km) and then mixed in a container. this mixture represented the used oil feedstok. the properties of used lubricant oil were measured at the petroleum research and development center laboratories /ministry of oil/iraq as shown in table 1. these measurements were done according to astm procedure. 1.2. solvents solvents used in this study were, analytical grade n-butanol, iso-butanol (hopkin & willams ind.), and heavy naphtha ( produced from alduraa refinery). 2. procedure 2.1. pretreatment settling and heating is the pretreatment step have to be made. used oils were allowed to homogenize and settle in a container so that free http://www.iasj.net/ hussein qasim hussein and ali laith abdulkarim -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 85 water and any settable suspended solids settled down. after that, the sample was heated to 105 o c to remove any remaining water and light cut contaminants [16]. 2.2. mixing used oil and solvent brought in contact together at different ratios (2:1 to 6:1) solvent to oil ratio (sor), at constant temperature (ambient), mixing time (30 min) and mixing speed (500 rpm) in order to determine the critical clarifying ratio (ccr). at this stage solvent extracted the base oil from used oil, while physical contaminants and chemical contaminants are segregated and settled down. the effect of these solvents were evaluated visually at the end of this stage. if the mixture (solvent and used oil) was separated in two layers (raffinate and extract), then the solvent is efficient, otherwise the solvent inefficient. 2.3. settling in order to let the dispersed solid (flocculated) particles to settle down, the well mixed mixture (used oil and solvent), leaved for 24 hours at room temperature. after this period of time two layers would form, the upper one was the extraction solvent and base oil, and the bottom liquid phase was heavier material (contaminants). 2.4. washing and drying after the mixture left to settle for 24 hrs., a sludgy black layer formed at the bottom of the flask. this layer was extracted, weighted, and marked as (wwet). the wetted layer was washed with the same employed solvent to remove any remaining trapped oil with the sludge, then the washed sludge heated to separate the excess solvent, weighted, and marked as (wdry). the percent oil losses (pol) and percentage of sludge removal (psr) was calculated according to the following formulas [17]: …(1) …(2) where: wo: the initial amount of used oil. wwet: the wetted sludge. wdry: the dried sludge. 2.5. recovery for recovering the base oil from solvent, the up layer was fed into distillation unit. the recovered solvent can be used directly again. the recovered base oil was marked as (woil).the recovered base oil will submit to some tests to determine either it can use again or not . in order to calculate the percentage of recovered base oil (yield), the following formula can be used [9]. …(3) where: woil the recovered base oil. wo the initial amount of used oil. results and discussions 1. single solvents figures 1, 2 and 3 shown the effect of solvent extraction process on, pol, psr, and the percentage of base oil yield as a function of the solvent: used oil ratio (sor), were calculated by using equation 1, 2 and 3 respectively; at ambient temperature (25± 2 o c), 500 rpm, mixing speed, and 30 min, mixing time. the base oil yield was increased, while the pol and psr were decreased with increasing sor, for all systems containing used oil and heavy naphtha, nbutanol, or iso-butanol solvent, with different magnitude. http://www.iasj.net/ investigation of binary solvents performance for regeneration of iraqi 15w40 waste lubricant 86 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net figure 1, shown that heavy naphtha solvent had the highest recovered base oil practically (91%), followed by n-butanol (90%), and isobutanol (86%). figure 2 verified that the solvent heavy naphtha had the lowest percentage of oil loss practically (1.38%), followed by nbutanol (6.52%), and iso-butanol (6.49%). figure 3 verified that the solvent iso-butanol had the highest percentage of sludge removal practically (10.61), followed by nbutanol (2.66%), and heavy naphtha (0.44%). the various in the key parameters percentage (yield, pol, psr) is caused by the difference of solubility of the base oil in these solvents. heavy naphtha yield percentage was the highest because of the low difference in solubility parameters between the used oil and heavy naphtha. as described by hildebrand [17], the smaller difference in solubility parameters of two compounds, the higher miscibility between them. with respect to nbutanol and isobutanol, n-butanol resulted in an efficient extraction performance rather than isobutanol. this behavior could be related to the carbon main chain magnitude which caused difference in molecular interaction of the solvent and the used oil and the solvent molecules configuration. these results in respect of the base oil yield and pol in agreement with the findings of elbashir et al., hamed et al., and hussein et al. [5, 9, 18], but the psr results disagree with the findings of durrani et al. 2012 and aremu et al. 2015 [12, 1], because it indicated by the experiment for any solvent weather it was polar, or hydrocarbon with increasing sor more of sludge would dissolve correspondingly. this behavior can be attributed to increase the solvent amount would increase the affinity, as a result. 2. binary solvents the investigated binary solvents were heavy naphtha : n-butanol and heavy naphtha : iso-butanol. three different ratios, (40:60), (30:70), and (20:80) of solvent to solvent were studied. the behavior of binary solvents were same as for the single solvents i.e. the base oil yield was progressively increased with increasing sor, while the pol and psr were decreased with increasing sor due to more of sludge would dissolve and/or disperse in the mixture with increasing sor as indicated in figure 4, 5 and 6, for the yield, pol, and psr respectively. a high yield was obtained with low pol and good psr, at low sor which would minimize the solvent used in the process and decrease the operation cost; this consider as a valuable advantage of binary solvent to be used. by examining the results shown in figure 4, it is verified that the highest base oil can be recovered at 30:70 solvent to solvent ratio for both of the binary solvents practically (95.5%), and (99.8) for heavy naphtha : n-butanol., and heavy naphtha : isobutanol respectively; the result shown in figure 5 verified that the lowest pol, could be achieved by 20:80 solvent to solvent ratio for heavy naphtha : n-butanol solvents practically (3.33%), and (30:70) for heavy naphtha : n-butanol solvents practically (5.9%); while figure 6 verified that the highest psr can be achieved at 20:80 for heavy naphtha : iso-butanol (6.7%), and 30:70 for heavy naphtha : nbutanol (7.11%). the optimum solvent to used oil ratio which called the critical clarifying ratio (ccr), were calculated graphically as described by elbashir [9]. figure 7 shown that the ccr value http://www.iasj.net/ hussein qasim hussein and ali laith abdulkarim -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 87 for n:nbut is 3.8 and for n:iso-but is 3.6, at 30:70 solvent to solvent ratio, which were the best binary solvent composition gave the best possible results (higher base oil yield, lower pol, and higher psr). fig. 1: the effect of single solvent:oil ratio on the percentage of base oil yield fig. 2: the effect of single solvent:oil ratio on the pol fig. 3: the effect of single solvent:oil ratio on the psr http://www.iasj.net/ investigation of binary solvents performance for regeneration of iraqi 15w40 waste lubricant 88 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net fig. 4: the effect of binary solvent:oil ratio on the percentage of base oil yield fig. 5: the effect of binary solvent:oil ratio on the pol fig. 6: the effect of binary solvent:oil ratio on the psr http://www.iasj.net/ hussein qasim hussein and ali laith abdulkarim -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 89 fig. 7: graphical determination of critical clarifying ratio (ccr) based on percentage of oil loss pol 2.1. effect of mixing time at optimum solvent : oil ratio (ccr), the mixtures were mixed by a magnetic stirrer for 15, 30 , 45, and 60 minutes at ambient temperature and constant mixing speed 500 rpm. the effect of mixing time for the two binary solvents on pol and psr indicated in figures 8 and 9 respectively. with increasing mixing time, the pol were correspondingly increased clearly recognized, as a result large portion of base oil cannot be separated. these results are in agreement with hussein et al. [19]. the best mixing time which given, in simultaneously, maximum sludge removal and minimum oil losses is (45 min) for n:n-but, and (30 min) for n:iso-but. 2.2. effect of mixing speed at optimum solvent : oil ratio (ccr), the mixtures were mixed by a beyond (30 min) for n:n-but and n:iso-but. this behavior can be attributed to that the more mixing time, the more of recoverable base oil trapped with sludge formed during mixing period, for this reason the psr was increased because the same solvent was used, and other parameters were constant. the inflection in the curves in figure 8, were due to at low mixing time the two layers were notmagnetic stirrer at 300, 500, 700 and 900 rpm mixing speed at ambient temperature and at best mixing time experimentally obtained. the effect of mixing speed for the studied binary solvents on pol and psr indicated in figures 10 and 11 respectively. show that with increasing mixing speed, pol and psr correspondingly increased until 700 rpm. further increasing leaded to decrease pol and psr. this behavior could be explained as, with increasing mixing speed the frequency of collision of impurities increased correspondingly; this would lead to raise pol and psr. rising of mixing time more than 700 rpm would act in opposite way i.e. this increment lead to dissociation of flocculated impurities during mixing period, that way the curvature appeared. the inflection in heavy naphtha: isobutanol curve in figure 10 can be attributed to the presence of isobutanol. where at low mixing speed the two layers were not completely separated, and more of base oil trapped with inefficiently flocculated particles. the best mixing time which given, in simultaneously, maximum sludge http://www.iasj.net/ investigation of binary solvents performance for regeneration of iraqi 15w40 waste lubricant 90 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net removal and minimum oil (700 rpm) for both of studied binary solvents. 2.3. effect of temperature at optimum solvent : oil ratio (ccr), the mixtures were mixed by a magnetic stirrer, with best mixing speed and mixing time experimentally obtained; at various temperatures 25, 30, 35, and 40 o c. the effect of temperature for different binary solvents type on pol and psr indicated in figures 12 and 13 respectively. the solubility and affinity increase with increasing of temperature, for this reason pol and psr decreased with increasing temperature due to more of impurities dissolved and/or dissociated with recovered base oil. the best mixing time which given, in simultaneously, maximum sludge removal and minimum oil losses was (35 o c) for both of studied binary solvents. these results are in agreement with the finding of hussein et al. and durrani et al. [19, 12]. the results indicated in table 1 have been obtained at the best operating values of mixing time, mixing speed, and temperature, for each optimum solvent : oil ratio (ccr) of the binary solvents which were experimentally found as previously expressed. decreasing of specific gravity value indicates that aromatic compounds and solids have been removed [12]. reducing the viscosity index (vi) value means that the nonmetallic polymeric viscosity index improvers separated out [20]. reduction of ash content value shows the presence of metallic impurities which is reduced by 45-55% in extracted oil. lowering ash content value indicates that dust, metals products, or products raised from the additives that contain metals have been removed. table 1: properties of used oil and recovered base oil at the best conditions properties used oil recovered base oil n:n-but n:iso-but specific gravity at 51 o c g/cm 3 viscosity at 40 o c ,cst viscosity at 100 o c, cst viscosity index (vi) ash content (wt%) total base number (mg hcl/g oil) total acid number (mg koh/g oil) yield (%) 0.8934 117.02 15.134 134.4 1.0511 0 3.5839 0.8802 44.893 7.197 121.2 0.6070 0 2.8542 87.75 0.8803 26.982 5.096 118.2 0.5767 0 2.1786 88.88 fig. 8: the effect of mixing time on percentage of oil loss pol for binary solvents http://www.iasj.net/ hussein qasim hussein and ali laith abdulkarim -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 91 fig. 9: the effect of mixing time on the psr for binary solvents fig. 10: the effect of mixing speed on the pol for different binary solvents fig. 11: the effect of mixing speed on the psr for different binary solvents http://www.iasj.net/ investigation of binary solvents performance for regeneration of iraqi 15w40 waste lubricant 92 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net fig. 12: the effect of temperature on percentage of oil loss pol for binary solvents fig. 13: the effect of temperature on percentage of sludge removal psr for binary solvents these results are better in performance and cheaper in composition than those obtained by durrani et al. [12], where they recovered 80% of the base oil from iraqi spent oil by using 0.25 isopropanol/0.35 nbutanol/0.40 mek composite solvent. conclusion the studied binary solvents were good in the process of regeneration of waste oil and cheap as heavy naphtha available locally. n:iso-but showed a better performance than n:n-but where, n:iso-but gave a lower value of viscosity index (vi), ash content, and tan; in addition the yield percentage were higher than n:n-but. references 1. aremu, m. o., araromi, d. o., and gbolahan, o. o., “regeneration of used lubricating engine oil by solvent extraction process”. international journal of energy and environmental research,vol.3, no.1, pp.1-12, march, (2015). 2. brandenberger, s., mohr, m., grob, k. and neukom, h. p., “contribution of unburned lubricating oil and diesel fuel to particulate emission from passenger cars”. atmospheric environment. 39, 6985 (2005). 3. rauckyte, t., hargreaves, d. j. and pawlak, z.,“determination of heavy metals and volatile aromatic compounds in used engine oils and sludges”. fuel, 85, 481 (2006). http://www.iasj.net/ hussein qasim hussein and ali laith abdulkarim -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 93 4. ogbeide s.o., “an investigation to the recycling of spent engine oil”. journal of engineering science and technology review , 3(1), 32-35 (2010). 5. hamad, a., al-zubaidy, e. and fayed, m. e., “used lubricating oil recycling using hydrocarbon solvents”. journal of environmental management, 74, 153 ( 2005). 6. clonfero, e. and schieppati, r., “reduction of polycyclic aromatic hydrocarbons from thermal clay recycled oils using technical adsorbents”. polycyclic aromatic compounds, 16, 41 (1999). 7. almutairi, a., bahzad, d. and halabi, m. a., “a comparative study on the performance of a catalyst system for the desulfurization of two kinds of atmospheric residues, kuwait export and eocene residual oils”. catalysis today, 125, 203 (2007). 8. ancheyta, j., betancourt, g., marroquín, g., centeno, g., castañeda, l. c., alonso, f., muñoz, j. a., gómez, ma. t. and rayo, p., “hydroprocessing of maya heavy crude oil in two reaction stages”. applied catalysis a: general, 233, 159 (2002). 9. elbashir, n.o., al-zahrani, s.m., abdul mutalib, m.i., and abasaeed, a.e., "a method of predicting effective solvent extraction parameters for recycling of used lubricating oils". journal of chemical engineering and processing, volume 41, pp. 765769, (2002). 10. smoluchowski, m. ,‘‘versuch einer mathematischen theorie der koagulationskinetic kolloider losunger’’. zeit. phys. chemie, 92, 129–168, (1917). 11. langelier, w. f., ‘‘coagulation of water with alum by prolonged agitation,’’. eng. news-record, 86, 924–928, (1921). 12. speight, j. g., and exall, d. i., “refining used lubricating oils”. crc press, taylor & francis group, boca raton, florida. ch. 1, and 2, (2014). 13. martins, j., “the extraction flocculation re-refining lubricating oil process using ternary organic solvents,”. ind. chem. res, vol. 36, 3854–3858, (1997). 14. durrani h.a., panhwar m.i. and kazi r.a., “re-refining of waste lubricating oil by solvent extraction”. mehran university research journal of eng. & tech., 30(2), 237246, (2011). 15. mahmood, s. m., msc. thesis, “study the effect of diferent working variables on the re-refining used lubricating oil and reduced the environmental conditions”. university of al-nahrain, chemical engineering dep., may, p. 35-52, (2015). 16. hani, f. b., and al – wedyan h., “regeneration of base-oil from wasteoil under different conditions and variables”. african journal of biotechnology, antje hansmeier, isbn: 978 – 90 – 386 – 2264 – 4, (2011). 17. durrani, h. a., panhwar, m. i., and kazi, r. a., “determining an efficient solvent extraction parameters for re-refining of waste lubricating oils”. mehran university research journal of engineering & technology, volume 31, no. 2, pp. 265-270, (2012). 18. hildebrand, j. h., prausnitz, j. m. and scott, r. l., “regular and related solutions: the solubility of gases, liquids and solid”. van nostrand reinhold co, new york (1970). 19. hussein, m., amer, a. a., and gaberah, a. s., “used lubricating oils re-refining by solvent extraction”. american journal of http://www.iasj.net/ investigation of binary solvents performance for regeneration of iraqi 15w40 waste lubricant 94 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net environmental engineering and science ; 1(3), pp. 44-50, (2014). 20. kamal, a., khan, f., “effect of extraction and adsorption on rerefining of used lubricating oil”. oil & gas science and technology, 64 (2), 191-197, (2009). http://www.iasj.net/ iraqi journal of chemical and petroleum engineering vol.17 no.4 (december 2016) 110 issn: 1997-4884 corrosion inhibition of carbon steel in hydrochloric acid under dynamic conditions q.j.m. slaiman and jaafar c. eirs chemical engineering department, college of engineering, al-nahrain university abstract in this work, studying the effect of ethylenediamine as a corrosion inhibitor was investigated for carbon steel in aerated hcl solution in range of 0.1-1n under dynamic conditions, i.e., rotational velocity of 400–1200 rpm in the temperature range 35 – 65 ºc. weight loss method was employed in absence and presence of the inhibitor as an adsorption type in concentration range 1000 – 5000 ppm using rotating cylinder specimens. the experimental results showed that corrosion rate in absence and presence of inhibitor is increased with increasing temperature, rotational velocity and concentration of acid. it is decreased with increasing inhibitor concentration for the whole range of temperature, rotational velocity and concentration of acid solution. under these conditions maximum inhibition efficiency obtained was 86% while minimum inhibition efficiency was 36%. the adsorption of this inhibitor on carbon steel surface is found to obey langmuir adsorption isotherm. key words: corrosion inhibition, carbon steel, hydrochloric acid, ethylenediamine, weight loss method, rotating cylinder. introduction carbon steel is employed widely in most industries due to its low cost, availability and ease of fabrication for various applications, e.g., condenser and heat exchanger tubes, tanks [1]. the corrosion of carbon steel in such environments and its inhibition constitute a complex problem. the pipelines, etc. corrosion characteristics of steel in aggressive mineral acid media have been widely investigated. corrosion of iron and its alloys and inhibition by different organic inhibitors in acid solutions have been studied by several authors [2]. hydrochloric acid is widely used for the removal of rust and scale in several industrial operations. it is the most difficult of common acids to handle from the standpoints of corrosion and materials of constructions. extreme care is required in the selection of materials to handle the acid by itself, even in relatively dilute concentrations or in process solutions containing appreciable amount of hydrochloric acid. this acid is very corrosive to most of the common metals and alloys. corrosion inhibition is the most common way of mitigating internalwalls corrosion in industrial facilities (pipelines, tanks, reactors, etc.). most of the well-known corrosion inhibitors are organic compounds containing nitrogen, sulfur and/or oxygen atoms university of baghdad college of engineering iraqi journal of chemical and petroleum engineering corrosion inhibition of carbon steel in hydrochloric acid under dynamic conditions 2 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net [3]. the corrosion protection by these inhibitors is based mostly on the modification of metal surfaces by surface adsorption of these molecules and subsequent formation of a protective (blocking) surface layer as self-assembled-monolayers (sams) on the metal surface, since these types of layers have been shown to offer better protection and tailoring (functionalization) properties than nonstructured (amorphous) adsorbed layers. experimental work the experimental work is divided into two parts, the first part using weight loss in order to determine the average corrosion rates without inhibitor under the following temperatures 35, 42, 50, 58 and 65 o c, velocities 400, 570, 800, 1030 and 1200 rpm, and acid concentrations0.1, 0.29, 0.55, 0.81 and 1n. these were performed to assess corrosion behavior of carbon steel. second part was executed in order to determine average corrosion rates in the presence of the inhibitor in the concentration range of 1000, 2000, 3000, 4000 and 5000 ppm and velocities of 400, 570, 800, 1030 and 1200 rpm, and acid concentration of 0.1, 0.29, 0.55, 0.81 and 1n which was performed to assess corrosion rates of carbon steel. these were executed at three temperature 35, 50, 65 o c. also, measurement of corrosion potential as a function of time against saturated calomel electrode (sce) was made for all weight loss experiments in parts 1 and 2. cylindrical carbon steel specimens were prepared in triplicate using a rotatable specimen’s holder. the surface area of each specimen was 7.85 cm 2 having dimensions of 1 cm long (l) and 2.5 cm outside diameter (do) which were measured using electronic digital caliper. the chemical composition of carbon steel is shown in table 1. it was analyzed by (xrf) in the department of engineering inspection, directorate of technical affair, ministry of science and technology. table 1 chemical composition of carbon steel metal c mn cu mo fe 0.09 0.57 0.18 0.06 balance a rotating shaft holder made of teflon on which three carbon steel specimens were fixed for rotation. the dimensions and shape of rce are shown in figure 1. fig. 1: rotating shaft holder, dimensions in (cm) five different solutions were prepared by diluting concentrated acid 11.5n using distilled water where the above concentration was prepares according to the flowing formula: n1v1 = n2 v2 …(1) the inhibitor used (ethylenediamine) is a colorless viscous liquid to light yellow substance at ambient temperature with purity 99.9 and structure formula c2h8n2. http://www.iasj.net/ q.j.m. slaiman and jaafar c. eirs -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 3 experimental procedure before each experiment the carbon steel specimen (working electrode) was abraded with glass emery paper of grade numbers; 180, 220, 400 and 2000 respectively, washed continuously with brushing by plastic brush under running tap water, followed by distilled water, dried with a clean tissue, rinsed with acetone and dried with clean tissue, followed by ethanol and dried with clean tissue. after that they were exposed to corrosion environment for 2 h immersion at desired concentrations of acid, and inhibitor. after each test, the specimen was washed by running tap water with brushing to remove the weakly adherent corrosion products formed on the specimen surface, washed with tap water, followed by distilled water, dried with clean tissue, rinsed with acetone, dried with clean tissue, followed by ethanol, dried with clean tissue, then the specimen was kept in a desiccator for 24 h to dry over silica gel, and accurately weighed to the fourth decimal of gram (w2) to determine corrosion rate as follows: c.r = (∆w)/ (a × t) …(2) for a rotating cylinder electrode with outer diameter, do (m), reynolds number is given by: re = (ρ do u)/μ …(3) the experimental runs were carried out in triplicate using the holder shown in figure 1. average corrosion was calculated and reported in present work. corrosion potential of the working electrode was recorded as a function of time against saturated calomel electrode sce using lugging capillary tip placed at a distance of 12 mm from the working electrode. an impedance voltmeter was used to read the potential directly. 1 rotating shaft (holder), 2 working electrode (specimen), 3 beaker, 4 water bath, 5 stirrer, 6 brush, 7 thermometer, 8 voltmeter, 9 luggin capillary tip, 10 reference saturated calomel electrode (sce), 11 electrical wires fig. 2: half-cell setup results and discussion the experimental work and the results analysis are employ to second-order rotatable design box-wilson design [4], which is also known as central composite rotatable design (ccrd) was used for experimental layout. in order to minimize the number of experimental runs for determining the corrosion rate of carbon steel due to hydrochloric acid, second order rotatable design of three independent variables was adopted. second order rotatable design was used to obtain the response within the region of the dimensional observation spaces, which allows one to design a minimal number of experimental runs. corrosion behavior of carbon steel in hydrochloric acid solution with and without inhibitor was studied under different conditions stated above. anodic reaction, which is the dissolution process of iron: fe fe +2 + 2e …(4) since the environment is acidic solution and not deaerated, so one of http://www.iasj.net/ corrosion inhibition of carbon steel in hydrochloric acid under dynamic conditions 4 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net the cathodic reaction takes place is oxygen reduction expressed as: o2 + 4h + +4e 2h2o …(5) the other cathodic reaction takes is hydrogen evolution reaction expressed as: 2h + + 2e h2 …(6) a. uninhibited solutions effect of velocity and temperature on the corrosion rate from figure 3 it is clear that increasing the flow velocity leads to an increase in the corrosion rate as presented for a given temperature. this can be attributed to the increase in the transport rate of oxygen close to the metal surface by eddy transport. the rate of oxygen reduction reaction is generally limited by the speed at which oxygen can reach the surface of the metal. previous studies [5, 6] indicate that the greater turbulence due to high velocities results in more uniform oxygen concentration near the surface, and that is clear in figure 4 where corrosion rate at 570 rpm (re = 28827) is lower than that at 1030 rpm (re = 52092) for a given temperature. from figure 4 it is clear that the corrosion rate increases with increasing temperature at a given rotational velocity. increasing temperature leads to change two variables that act in a conflicting way. firstly, increasing temperature accelerates the reaction rates of both reactions as dictated by arrhenius equation. moreover, diffusion rate of dissolved oxygen is also increased due to increased molecular diffusion coefficient. secondly, as the temperature increases the oxygen solubility decreases [7, 8]. this is clear in figure 3 where corrosion rate at 58 o c is higher than that at 42 o c. therefore; increasing re (or velocity) will increase increasing amount of oxygen arriving to the surface and hence the corrosion rate is increased. increasing (re) leads to decrease the thickness of diffusion layer in the wall vicinity that represents the main resistance to oxygen transport [9]. figure 5 illustrates that the corrosion rate increases with increasing velocity, but at high velocities the corrosion rate is nearly constant with increasing velocity. this is attributed to limited influence of agitation at high velocities. figure 6 and figure 7 show the 3d surface plot of corrosion rate against temperature and velocity. fig. 3: variation of corrosion rate with velocity at different temperatures in acid concentration of 0.29 n for 2 h immersion time http://www.iasj.net/ q.j.m. slaiman and jaafar c. eirs -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 5 fig. 4: variation of corrosion rate with temperature at different rotational velocities and 0.29 n acid concentration for 2 h immersion time fig. 5: variation of corrosion rate with re at 50 o c and 0.55 n acid concentration for 2 h immersion time fig. 6: 3d surface plot of corrosion rate against temperature and velocity 200 300 40 50 60 400 40000 2000060 60000 40000 60000 corr. rate in gmd re t emperature (c) surface plot of corr. rate in gmd vs re, temperature (c) http://www.iasj.net/ corrosion inhibition of carbon steel in hydrochloric acid under dynamic conditions 6 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net fig. 7: contour plot of corrosion rate against temperature and velocity corrosion kinetic parameters in general, the rate of most chemical reactions increases with temperature following arrhenius equation. temperature favors the kinetics of corrosion reactions and more specifically, the anodic dissolution of the metal. the activation energy of the corrosion process can be obtained from the plots of arrhenius according to the following equation: corrosion rate = …(7) where ea is the activation energy of the process (j/mol), r is the universal gas constant (8.314 j/ (mol.k)), t is the temperature (k) and a arrhenius is a constant. taking the logarithm of the arrhenius equation yields: log (corrosion rate)=log a− …(8) the value of activation energy of corrosion in 0.81 n hcl can be determined from the slope of log (corrosion rate) versus 1/t plots. actual values of activation energy for each case of carbon steel corrosion with temperature variations in the range of 35 to 65 o c and rotational velocity, i.e., 570, 800, and 1030 rpm are plotted according to equation 7 in figure 8 and figure 9. from the gradient of the plotted curves, the calculated ea values are listed in table 2. b. inhibited solutions effect of velocity and temperature in presence of inhibitor on corrosion rate figure 10 indicates the variation of corrosion rate with flow velocity in absence and presence of 3000 ppm at 50 o c and 2 h immersion time. one can see from figure 10 that the corrosion rate increases with velocity at 50 o c in the absence of the inhibitor. it decreases with the addition of inhibitor i.e., at constant temperature, the corrosion rate increases with increasing flow rate. these increases are much lower than that in uninhibited solutions. an increase in the rotational velocity from 400 to 1200 rpm (re of 23579 to 70743) at 3000 ppm inhibitor concentration and 50 o c (central condition of rotatable design) gives an inhibition efficiency of 70%, 64%, 51% at 400, 800 and 1200 rpm respectively. figure 11 shows the variation of corrosion rate with temperature in the absence and presence of 3000 ppm of the inhibitor temperature (c) r e 65605550454035 70000 60000 50000 40000 30000 > – – – – < 200 200 250 250 300 300 350 350 400 400 gmd corr. rate in contour plot of corr. rate in gmd vs re, temperature (c) http://www.iasj.net/ q.j.m. slaiman and jaafar c. eirs -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 7 concentration at 800 rpm and 0.55 n acid solution concentration. figure 11 clearly shows concentration acid the corrosion rate increases with increasing temperature at 800 rpm without the inhibitor, while it decreases with its addition, i.e., at constant velocity. these increases are much lower than that in uninhibited solutions. an increasing in the temperature from 35 to 65 o c at 3000 ppm inhibitor concentration and 800 rpm in 0.55 n acid concentration (central condition of rotatable design), the inhibition efficiency is found to be 67%, 64%, and 47% at 35, 50 and 65 o c respectively. as shown in figure 11 the corrosion rate linearly increases with the increase of temperature. in an inhibited acid at an elevated temperature the metal dissolution reaction is complex and causes the following changes [11]: a) desorption of pre-adsorbed inhibitor molecules occur from metal surface. b) the active area of the metal surface changes because of rapid etching. c) decomposition and rearrangement of some inhibitors may take place. d) heterogeneous reaction rate increases at uninhibited metal surface. the adsorption and desorption of inhibitor molecules continuously occur at the metal surface. at a particular temperature equilibrium is set up between these two processes. fig. 8: arrhenius plots in 0.81 n hcl, uninhibited solution fig. 9: arrhenius plots in 0.0.55 n hcl, uninhibited solution and velocity 800 rpm http://www.iasj.net/ corrosion inhibition of carbon steel in hydrochloric acid under dynamic conditions 8 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net table 2: activation energy values for uninhibited solutions velocity (rpm) ea (kj/mol) log a (gmd) conc.of solution (n) 570 14.99 2.52 0.81 800 29.6 2.82 0.55 1030 29.32 2.64 0.81 fig. 10: variation of corrosion rate with re in the presence of 3000 ppm and concentration solution 0.55 n for 2 h immersion time fig. 11: variation of corrosion rate with temperature in the absence and presence of 3000 ppm concentration inhibitor and 0.55 n solution concentration at 800 rpm and 2 h immersion time figure 12 illustrates the variation of ie% with inhibiting concentration at 800 rpm and 35 o c in 0.55 nacid solution. figure 12 shows that the inhibition efficiency for 800 rpm is 86% at 5000 ppm and 67% and 48% at 3000 ppm and 1000 ppm respectively. this reveals that the efficiency at 5000 ppm is almost high, and this means that these concentrations (figure 12) are good enough to form a protective layer. the surface coverage (θ) data are very useful while discussing the adsorption characteristics [12]. the surface coverage of inhibitor at a given concentration is calculated using the following equation: …(9) where c.rin and c.run are the corrosion rates with and without inhibitor respectively. the corrosion rate data can be used to analyze the adsorption mechanism. the langmuir isotherm is expressed as: http://www.iasj.net/ q.j.m. slaiman and jaafar c. eirs -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 9 kc kc   1  …(10) where k is the equilibrium constant for the adsorption isotherm representing the degree of adsorption (i.e. the higher the value of k indicates that the inhibitor is strongly adsorbed on the metal surface. c is inhibitor concentration (ppm) and θ is the surface coverage. rearranging equation will give: c k c  1  …(11) figure 13 shows plots of c/θ vs. c for ethylenediamine as corrosion inhibitor in 0.55 n hcl acid at 35, 50 and 65 ºc. the data fit straight lines indicating that ethyelendiamine is adsorbed according to the langmuir adsorption isotherm from the intercept of straight line on the c/θ axis, k values are to be calculated as given in table 3. the rectilinear natures of figure 13 indicate an increase in adsorption with an increase in concentration of and that adsorption occurs in accordance with langmuir adsorption equation. it is also noted in figure 13 that the lines accumulated and approximately looked like one line this is due to the very close range of inhibition efficiency (36 – 86%). fig. 12: variation of ie% with inhibitor concentration at 800 rpm and 35 o c in 0.55 n acid solution fig. 13: langmuir adsorption isotherm of ethylenediamin on low carbon steel in 0.55 n hcl and 800 rpm as flow velocity at different temperature http://www.iasj.net/ corrosion inhibition of carbon steel in hydrochloric acid under dynamic conditions 10 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net table 3: equilibrium constant for langmuir type adsorption of the inhibitor in 0.55 n hcl acid solution and 800 rpm as flow velocity at different temperatures temperature ( o c) k value (g/l) slope 35 0. 97 1.07 50 0. 5 1.12 65 0. 34 1.22 conclusions 1. corrosion rate in absence and presence of the inhibitor is increased with the increasing temperature of the corrosive solution and the rotational velocity. 2. corrosion rate decreases with increasing the inhibitor concentration for the whole range of temperatures and rotational velocities. 3. the efficiency of inhibitor increases with increasing inhibitor concentration and also increases with decrease in temperature and flow velocity. 4. the maximum inhibition efficiency obtained was 86% and the minimum inhibition efficiency obtained was 36%. 5. increased adsorption with an increase in concentration of inhibitor and that adsorption occurs in accordance with langmuir adsorption isotherm. references 1. adnan s.abdul nabi and hanan m.ali, (2009), ”corrosion inhibition of carbon steel on hydrochloric acid using zizyphus spina – chritisi extract”, journal basrah researches (sciences) vol. 35, no. 1. 2. g.y. elewady, (2008), “pyrimidine derivatives as corrosion inhibitors for carbon-steel in 2m hydrochloric acid solution”, int. j. electrochem. sci. 3, pp 1149 – 1161. 3. m.a. deyab, “effect of cationic surfactant and inorganic anions on the electrochemical behavior of carbon steel in formation water”, corros. sci., vol.49, pp.2315, 2007. 4. zˇivorad r. lazic (2004), “design of experiments in chemical engineering “, wiley-vch, p625. 5. shreir, l. l., jarman, r. a., and burstein, g. t., (2000), “corrosion metal / environment reactions”, volume 2, third edition, butterworth-heinemann, great britain. 6. slaiman, q. j. m., and hasan b. o., (2010) “study on corrosion rate of carbon steel pipe under turbulent flow conditions” the canadian journal of chemical engineering, vol. 88, pp. 1114 1120. 7. shreir, l. l., jarman, r. a., and burstein, g. t., “corrosion metal / environment reactions”, volume i, third edition, butterworth heinemann, great britain, 2000. 8. henry, s. d. and w. m. scott, “corrosion in the petrochemical industry”, asm international, first edition usa, (1999). 9. brodkey, r. s., and hershey, h. c., “transport phenomena”, 2 nd edition, mc graw hill, new york,1989. 10. ioto,ca;mohammed, "the effect of cashew juice extract on corrosion inhibition of mild steel in hcl" (http://www.kfipm.edu.sa). 11. v. s. sastri, (2011), “green corrosion inhibitor “, john wiley & sons, inc. 12. yaro a.s., ph.d. ., chemical engineering department, thesis university of baghdad, jun. (1996). http://www.iasj.net/ http://www.kfipm.edu.sa/ available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.19 no.4 (december 2018) 12 – 27 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: kadhim hmood mnati, email: eng-petkadhim@yahoo.com, hassan abdul hadi, email: hahah692000@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. prediction of penetration rate and cost with artificial neural network for alhafaya oil field kadhim hmood mnati a and hassan abdul hadi b a missan oil company b university of baghdad college of eng. petroleum dept. abstract prediction of penetration rate (rop) is important process in optimization of drilling due to its crucial role in lowering drilling operation costs. this process has complex nature due to too many interrelated factors that affected the rate of penetration, which make difficult predicting process. this paper shows a new technique of rate of penetration prediction by using artificial neural network technique. a three layers model composed of two hidden layers and output layer has built by using drilling parameters data extracted from mud logging and wire line log for alhalfaya oil field. these drilling parameters includes mechanical (wob, rpm), hydraulic (his), and travel transit time (dt). five data set represented five formations gathered from five drilled wells were involved in modeling process.approximatlly,85 % of these data were used for training the ann models, and 15% to assess their accuracy and direction of stability. the results of the simulation showed good matching between the raw data and the predicted values of rop by artificial neural network (ann) model. in addition, a good fitness was obtained in the estimation of drilling cost from ann method when compared to the raw data. keywords: rate of penetration, artificial neural network received on 01/10/8102, accepted on 05/11/8102, published on 01/08/8102 https://doi.org/10.31699/ijcpe.2018.4.3 1introduction during the last decades, drilling operations have witnessed significant progress to improve down hole drilling techniques. drilling optimization techniques have been extensively used to minimize drilling operation costs by reducing nonproductive time ‎[1]. at the present time, there is no representative mathematical relationship between rate of penetration and drilling parameters due to large number of uncertain drilling variables that influenced the drilling rate and also the complex and nonlinearity relationship between them ‎[2]. rate of penetration is affected by two types of parameters, which are controllable and uncontrollable parameters .the controllable parameters are related to mechanical (wob, rpm), hydraulic, drilling fluid properties, well configuration, and type of bit, while the uncontrollable parameters are related to formation properties ‎[3]. during the last decades, drilling optimization techniques adopted new methods for solving drilling optimization problems. these new methods include artificial intelligence (ai) such as genetic algorithm (ga), and artificial neural network (ann) methods. m.h.bahari et al (2008) applied ga method to calculate constant coefficients of bourgoyne and youngs rop model for solving problems where the model had proven to be meaningless in some cases .the results of simulation had proven to be proficient to determine that coefficients of bourgone and young rop model ‎[4]. jahanbakhshi,r,et al.(2012) developed an ann model to investigates and predict the rop in one of southern iran's oil field, by considering type of formation , mechanical properties of rock, hydraulics factors, bit type, and mud properties. the results showed the efficiency of ann model for field application, and for drilling planning for any oil and gas wells in the related field ‎[5]. m.bataee et al (2011) developed an ann model to determine complex relationship between drilling variables. their model predicted the exact penetration rate, optimization of drilling parameters, time of the drilling of wells, and lowering the drilling cost for future wells ‎[6]. in this study, a new model of rate of penetration based on the artificial neural network (ann) is build using the matlab programming computer. results of predicted model showed good convergence when compared with others model and a good estimation of drilling cost. https://doi.org/10.31699/ijcpe.2018.4.3 k. h. mnati and h. abdul hadi / iraqi journal of chemical and petroleum engineering 19,4 (2018) 21-27 22 2artificial neural network approach artificial neural network are powerful techniques used in modeling complex systems that seeks to simulate human brain behavior by treatment of data on the basis of trial and error. ann has been identified as tool to determine and optimize complicated nonlinear relationships between parameters ‎[6]. in petroleum industry, artificial neural networks (anns) has accepted a wide applications such as prediction of hole pressure, fracture pressure, pore pressure, and the instability of wellbore. ann is massively parallel –distributed treatment units called neurons. these simple neurons have specific performance characteristics in common with biological neurons. artificial neural network is usually consisted of multilayers. these layers are input layer, one or more hidden layers, and one output layer. the number of input neurons is usually corresponds to the number of parameters that are being presented to the network as inputs, also, the same thing for the output layer. for the hidden layers and neurons, their number is unknown and can be unlimited. the neurons are arranged and organized in different forms depending on the type of the network (architecture).the layers of neurons are linked by the connection weight, which then formed the ann. the most common ann architecture is the feed forward with back propagation artificial neural network, in which the information will propagate in one direction from input to output ‎[7]. the structure or topology of feed forward ann is shown in fig. 1. the first step in ann modeling is the training or learning process. the training process is a procedure to estimate the weights and thresholds by using an appropriate algorithm (activation function). each neuron has different activation functions, which are used to process data. generally, the data is divided randomly in three sets, training set, validation set, and testing set. the validation set is used to stop training process to prevent the network from over fitting the data. fig. 1. structure of ann model 3region of study in order to build the model, field data from al-halfaya oil field was extracted from mud logging unit and sonic log. al-halfaya oilfield is located in missan province in the southeast of iraq, 35 kilometers southeast to amara city. the data used in this study are provided by petro china company limited (from contractor bohai mudlogging), that working in al-halfaya oil field. modeling data are extracted from five vertical wells called (hf004-m272, hf051-n051, hf109n109, hf195-n195and hf004n004) for five formation called (fars formation, kirkuk formation, hartha formation, mishraf formation and nahar umar formation). each formation represented dataset. for ann modeling purpose, the rop was considered as dependent variable, while the (wob, rpm, hsi and dt) were considered as independent variable. the interval transit time (dt) is the reciprocal of sonic speed in the rock and express in (μsec/ft). five data sets are considered in the modeling which represented five formations. these parameters represented the mechanical, hydraulic and formation strength, which are the most important parameters. table 1 depicts the final input parameters for ann modeling. table 1. input parameters for ann modeling parameter unit weight on bit ton rotary speed rpm hydraulic hsi transit time msec -1 before the input data is applied to the network, it should processed by normalization function .to scale the data for each input variable, a known method called min-max normalization method, which linearly scales the data to values between 0 and 1 using the following equation: (1) where x is the value of the parameter to be noramalized, xmin and xmax are minimum and maximum values respectively. with this method, the output of network will always falls into a normalized range. 4training the network it’s well known that using of powerful nonlinear regression models is associated with the possibility of over fitting data. in order to obtain the optimal size of the neural network model, a heuristic approach was applied. here, there is possibility to increase the number of hidden layers to two or three if the results with one are still not adequate. k. h. mnati and h. abdul hadi / iraqi journal of chemical and petroleum engineering 19,4 (2018) 21-27 22 however, increasing the numbers of neurons in the hidden layers or increasing the number of hidden layers will increase the power of the network model, but will required more computation processes and lead to produce over fitting ‎[7]. in order to avoid over fitting data during the developed stage of the model, the field data of five sets was divided into three subsets which are training subset, validation subset, and testing subset. the set of training is used to calibrate the model. it is used for calculating the gradient and updating the network weights and biases. the set of validation is used to verification the generalization of the developed model during the learning phase. the validation errors will decrease normally during the initial phase of training, which also the training set error. the set of testing is used to examine the final calculation of the network and compare different models. for the model building process, the available dataset consisted of 85% for the pure network leaning process, and 15% for validation. 5results of simulation while developing ann model, the three layered network showed the lowest network error. also, different structures in the three layered have been tested as well and the comparison between these structure showed that the three layered with 20 hidden neurons in the hidden layer is the best model. as it shown in the fig. 1, a three layer feed forward network which use activation function for the hidden layer and pure line for output layer and full connection topology between layers is used. this algorithm can approximate any nonlinear continuous function to an arbitrary accuracy [7]. the performance of the ann model can be evaluated on the basis of efficiency coefficient(r). table 2 gives the r values for the five data sets from a to e as follows: table 2. results of network model for five data sets in term of r dataset no.of data training r a 1800 0.91261 b 550 0.96893 c 374 0.83361 d 469 0.94061 e 397 0.92163 performance of the best ann model for each data sets are shown in fig. 2 through fig. 6. as it seen in all figures, an increase in number of training attempts would accompany by an improvement in performance of ann model due to reduction of mean square error (mse) values and thereby could obtained good predicted values of rate of penetration (rop). fig. 2. neural network training performance for dataset a fig. 3. neural network training performance for dataset b fig. 4. neural network training performance for dataset c fig. 5. neural network training performance for dataset d k. h. mnati and h. abdul hadi / iraqi journal of chemical and petroleum engineering 19,4 (2018) 21-27 22 fig. 6. neural network training performance for dataset e the regression analysis of ann model for five data sets (a, b, c, d, and e) could be seen in fig. 7 through fig. 11. these figures show the regression plots of predicted rate of penetration against field data. the efficiency coefficient values (r) for training process shows excellent convergence between the predicted and actual values of rop for all data sets. also each data set has special regression equation as shows on y-axis. fig. 7. neural network regression for dataset a fig. 8. neural network regression for dataset b fig. 9. neural network regression for dataset c fig. 10. neural network regression for dataset d fig. 11. neural network regression for dataset e fig. 12 through fig. 16 shows the matching between the predicted and measured data in term of rop for the five datasets. the output of the ann model shows a good agreement matching at wide range of depth with the raw data. k. h. mnati and h. abdul hadi / iraqi journal of chemical and petroleum engineering 19,4 (2018) 21-27 22 fig. 12. training data comparison between field and ann model of dataset a fig. 13. training data comparison between field and ann model of dataset b fig. 14. training data comparison between field and ann model of dataset c fig. 15. training data comparison between field and ann model of dataset d fig. 16. training data comparison between field and ann model of dataset e 6estimation of drilling cost as mentioned earlier, the objective of drilling optimization is to reduce the drilling operation cost. in this section the proposed ann model was tested again by estimation of drilling cost for certain well (hf004) and specific depth (from depth 147 m to1390 m) for each dataset. the following information in table 3 is obtained from field operating company. table 3. data of cost estimation cost of rig, $/d 30000 cost of bit,$ 5000 rotating time,hr 16 trip time,hr 1.5 connection time,min 1 k. h. mnati and h. abdul hadi / iraqi journal of chemical and petroleum engineering 19,4 (2018) 21-27 22 the estimation of cost of drilled footage was done with following equation: (2) where cpm is cost per meter, cb is bit cost, cr is rig cost, tr is rotation time, tt is trip time, tc is connection time, and f is the number of drilled footages. the performance of proposed ann model in term of estimation of drilled footage is presented in fig. 17 through fig. 21 for five datasets. fig. 17. comparison between predicted drilled cost by ann model and actual data for data set a fig. 18. comparison between predicted drilled cost by ann model and actual data for data set b fig. 19. comparison between predicted drilled cost by ann model and actual data for data set c fig. 20. comparison between predicted drilled cost by ann model and actual data for data set d fig. 21. comparison between predicted drilled cost by ann model and actual data for data set e all these results demonstrated that the cost of drilled footage predicted by the proposed ann model has accurate drilled cost and matched concisely with the actual field data. so, these calculations support the accuracy of the neural network model. k. h. mnati and h. abdul hadi / iraqi journal of chemical and petroleum engineering 19,4 (2018) 21-27 22 7conclusions based on the previous calculation, an artificial neural network model of three layers for estimating rate of penetration of alhalfaya oil field could be constructed with aid of five data sets from mud and wire line logs. a large training process for each data set were conducted due to high quantity of field data and could be obtained high performance of ann model by reducing the mean square error to minimum level, and improving the value of efficiency coefficient. the ann proposed model showed good feasibility and accuracy when it applied for estimation the rate of penetration in five formations due to high matching with the raw data. also, economic application of the proposed ann model for estimation the cost of drilled footage in five data sets showed their capability for yielding quite accurate outcome. nomenclature cpm: cost per meter,$/m cr: rig cost, $/hr f: no of drilled meter,m r: efficiency coefficient tc: connection time,hr tr: rotation time, hr tt: trip time, hr references [1] rahimzadeh,h.et al.,2010.comparison of the penetration rate models using field data for one of the gas fields in persian gulf area.in proceedings of international oil and gas conference and exhibition in china.society of petroleum engineers. [2] mendes,j.r.p.,fonseca,t.c.& serapiao,a.,2007.applying agenetic neurol model reference adaptive controller in drilling optimization.world oil,228(10). [3] wang,f.& salehi,s.,2015.drilling hydraulic optimization using neurol networks.spe 173420,spe digital energy conference and exhibition,texas,usa,3-5 march. [4] bahari,m.,h. et al(2008).determining bourgoyne and young model coefficients using genetic algorithm to predict drilling rate.journal of applied science 8(17):3050-3054. [5] jahanbakhish,r.and keshavarzi,r.,2012.real-time prediction of rate of penetration during drilling operation in oil and gas wells.46 th american rock mechanics/geomechanics symposium,chicago,il,usa,24-27 june. [6] bataee,m.& mohseni,s.,2011.application of artificial intelligent systems in rop optimization:a case study in shadegan oil field.spe 140029,spe middle east unconventional gas conference and exhibition,muscat,oman,31 january-2 february. [7] bontempi,g.,bersini,h.& birattari,m.,2001. the local paradigm for modeling and control:from neuro-fuzzy sets and systems,121(1),pp.59-72. الحمفاية النفطي تخمين معدل الحفر والكمفة بواسطة الشبكة العصابية الصناعية لحقل الخالصة اىمية كبيرة في الحفر االمثل بسبب تاثيره المحوري عمى كمفة عمميات التخمين الدقيق لمعدل الحفر ذو الحفر. وعادة يكون ىذا التخمين صعب بسبب تداخل العوامل التي تؤثر عمى عممية الحفر.في ىذا البحث تم ,حيث تم بناء موديل الصناعية كاسموب جديد لتخمين معدل الحفر والكمفةاستخدام طريقة الشبكة العصابية الشبكة العصابية من ثالثة طيقات اثنان مخفية وواحدة لمنواتج باستعمال بيانات مجسات الطين والمجسات ,سرعة االخرى لحقل الحمفاية النفطي. العوامل التي تم اسخدام قيميا ىي العوامل الميكانيكية )الوزن المسمط الدوران(,العوامل الييدروليكية,وزمن انتقال الموجة الصوتية . %من البيانات 58تم استخدام خمس مجاميع لمبيانات والتي نمثل خمس تكوينات في الحقل حيث تم استخدام موديل % الختبار صالحيتو. بينت النتائج التطابق الجيد لقيم معدل الحفر المحتسبة من ال58لتدريب الموديل و مع القيم المقاسة وكذلك لقيم الكمفة المحتسبة مع القيم االصمية. https://www.onepetro.org/conference-paper/spe-131253-ms https://www.onepetro.org/conference-paper/spe-131253-ms https://www.onepetro.org/conference-paper/spe-131253-ms https://www.onepetro.org/conference-paper/spe-131253-ms https://www.onepetro.org/conference-paper/spe-131253-ms https://repositorio.unesp.br/handle/11449/69926 https://repositorio.unesp.br/handle/11449/69926 https://repositorio.unesp.br/handle/11449/69926 https://repositorio.unesp.br/handle/11449/69926 https://www.researchgate.net/profile/mohamad_bahari/publication/26560452_determining_bourgoyne_and_young_model_coefficients_using_genetic_algorithm_to_predict_drilling_rate/links/546b0a9e0cf2f5eb18079c72.pdf https://www.researchgate.net/profile/mohamad_bahari/publication/26560452_determining_bourgoyne_and_young_model_coefficients_using_genetic_algorithm_to_predict_drilling_rate/links/546b0a9e0cf2f5eb18079c72.pdf https://www.researchgate.net/profile/mohamad_bahari/publication/26560452_determining_bourgoyne_and_young_model_coefficients_using_genetic_algorithm_to_predict_drilling_rate/links/546b0a9e0cf2f5eb18079c72.pdf https://www.researchgate.net/profile/mohamad_bahari/publication/26560452_determining_bourgoyne_and_young_model_coefficients_using_genetic_algorithm_to_predict_drilling_rate/links/546b0a9e0cf2f5eb18079c72.pdf https://www.onepetro.org/conference-paper/arma-2012-244 https://www.onepetro.org/conference-paper/arma-2012-244 https://www.onepetro.org/conference-paper/arma-2012-244 https://www.onepetro.org/conference-paper/arma-2012-244 https://www.onepetro.org/conference-paper/spe-140029-ms https://www.onepetro.org/conference-paper/spe-140029-ms https://www.onepetro.org/conference-paper/spe-140029-ms https://www.onepetro.org/conference-paper/spe-140029-ms https://www.onepetro.org/conference-paper/spe-140029-ms http://iridia.ulb.ac.be/mbiro/paperi/bonberbir2001fss.pdf http://iridia.ulb.ac.be/mbiro/paperi/bonberbir2001fss.pdf http://iridia.ulb.ac.be/mbiro/paperi/bonberbir2001fss.pdf available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.21 no.2 (june 2020) 1 – 6 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: noor a.a. mohammed , email: mn.r_86@yahoo.com, name: abeer i. alwared, email: abeerwared@yahoo.com , name: mohammed s. salman, email: iraqmas68@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. decolorization of reactive yellow dye by advanced oxidation using continuous reactors noor a.a. mohammed a , abeer i. alwared a and mohammed s. salman b a department of environmental engineering/ college of engineering/ university of baghdad b avi-cenna e-learning center / university of baghdad abstract the photocatalytic decolorization of reactive yellow dye from aqueous solution was investigated by using tio2 photocatalyst. heterogeneous photocatalytic processes applied under natural weathering conditions, in the presence of uv lamp show a promising degradation capability. in this study, synergistic effects of factors such as flow rate, and number and intensity of uv lamps were scrutinized in continuous photocatalytic reactor at constant best conditions obtained from the batch reactor tests ph=7, tio2 concentration (25mg/l) , 400 mg/l dosage of h2o2. moreover .the maximum removal of dye achieved at 60 minutes, in the presence of two uv-light, 20mg/l dye concentration and at (5 l/h) flow rate was found to be 95.47%, also the reaction was found to be of a first order throughout the system. keywords: reactive yellow dye; photo-degradation; heterogeneous catalysis; water treatment. received on 09/09/2019, accepted on 31/10/2019, published on 30/06/2020 https://doi.org/10.31699/ijcpe.2020.2.1 1introduction wastewater contaminated with toxic organic materials poses a serious threat to the environment [1]. color is the first pollutant identified in wastewater and must be removed before discharging into land or water. the presence of traces of dye in water (less than 1 mg/l in some dyes) is very clear and affects the aesthetic value of lakes, rivers and other water bodies, water transparency and gas solubility. decolorization of water is usually more important than the removal of soluble and colored organic matter, which is usually a large part of the biochemical oxygen demand (bod). however, dyes are more difficult to handle because of their artificial origin and mostly aromatic complex structures [2]. removal of dyes is difficult and poorly efficient due to the use of conventional physic-chemical and biological methods [3]. conventional techniques for removing dyes from wastewater are adsorption, biological filtration, coagulation and ozone treatment. every technique has its advantages and disadvantages. such as, adsorption is not destructive because it simply moves the dye from the water to another stage, causing secondary pollution. therefore, there is a need to reprocess the absorbed materials and solid waste, which is an expensive process. traditional biological treatment techniques are ineffective for degradation and decolorization due to the presence of large amounts of aromatic hydrocarbons in dye molecules and the stability of modern dyes. also, most dyes are adsorbed only on the sludge without degradation. filtration may provide pure water, but pigments with low molar mass may pass through the filtration system. the use of alum, iron salts or lime is also a low cost method. however, it needs waste treatment. finally, although ozone does not require treatment, it suffers from high operating costs [4]. through the past few years, advanced oxidation processes (aop) were chosen as an alternative to water purification. aop was divided into two classes (heterogeneous catalysis and homogeneous catalysis). heterogeneous catalysis was successfully used to reduce various hazardous substances [5]. aops are based on the generation of hydroxyl radical ( · oh) which have the ability to decompose organic pollutants into carbon dioxide, water and inorganic materials. several of aops techniques include chlorination, ozonation, fenton, photo-fenton, photocatalytic and wet-air oxidation .hydroxyl radicals attack the organic molecules causing their destruction and mineralization.also, another method is the photocatalyst with titanium dioxide that is a wide band gap semiconductor and it is used nearuv light of wavelength shorter than 380 nm or sunlight. main factor that affects the photo-decolourization of dyes is ph of the reaction solution. it describes the charges on the surface of the photocatalyst and it also manipulates the kinetics of organic compounds degradation. all the three possible reaction mechanisms such as (1) hydroxyl radical attack, (2) direct oxidation by the positive hole and (3) direct reduction by the electron from the conducting band can be influenced by ph. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:mn.r_86@yahoo.com mailto:abeerwared@yahoo.com mailto:iraqmas68@yahoo.com http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2020.2.1 n. a.a. mohammed et al. / iraqi journal of chemical and petroleum engineering 21,2 (2020) 1 6 2 the positive hole is seemingly ready to oxidize a water molecule to hydroxyl radical. the hydroxyl radical, in turn, is a powerful oxidant .hydrogen peroxide has low cost and available which was formed hydroxyl radicals by the photolytic dissociation of hydrogen peroxide in water by uv irradiation at a wavelength of 254nm[6] . medium pressure uv lamps produce a higher radical generation. the processes of h2o2/tio2/uv treatment depend on many conditions that have an effect on the degradation of organic pollutants. the conditions include the type and concentration of the organic materials, hydrogen peroxide concentration, tio2 amount, light source, ph, temperature, flow rate and reaction time [7]. huang et al. [8] studied the parameter of adding the amount of hydrogen peroxide to remove the methyl orange from solution. the removal efficiency was increased with increasing h2o2 concentration. zhiyong et al. [9] studied the addition of hydrogen peroxide with titanium dioxide degussa p25 (0.5mg/l) catalyst (1mm) to remove methyl orange solution under sunlight irradiation. senthil kumar et al. [10] reported that the increase in the oh concentration will cause the reduction of the hydrogen peroxide [11]. ali 2017 [12] studied the continuous photo-catalytic reactor using tio2/uv process to treat produced wastewater solution, and the results showed that the rate of degradation of organic pollutants decreased with the increase in the flow rate while it increased with increasing the number of the uv lamp. therefore, the goal of this research is to study the effectiveness of the aops in the continuous mode to degrade reactive yellow dye from aqueous solution under the influence of flow rate, intensity of uv lamp and initial dye concentration. 2material and method 2.1. materials the reactive azo yellow dye (r-yellow) which is illustrated in fig. 1, was supplied by al-hilla textile factory south of baghdad, (department of dying and printing). tio2-p25 as powder was supplied by fluka (china) with 99% purity (molecular weight 79.87g/mol). the hydrogen peroxide h2o2 (50% w/w) was obtained from merck. the ph value of the aqueous solution was adjusted to7 using hcl and/or naoh. fig. 1. chemical structure of reactive yellow[13] 2.2. uv lamps two types of uv lamp were used in the experiments. ultraviolent radiation (254 nm) was produced from 1.25 cm diameter and 21 cm length type (tuv 6 w 4p-se, philips, england) and the other one was (11w 4p-se, england). uv lamp was sheathed in quartz sleeve for protection (2.5 cm in diameter and 22 cm in length) as shown in fig. 2. the intensity of uv-c of 6w and 11w lamps was 400 mw/cm 2 and 600 mw/cm 2 , respectively. fig. 2. uv lamp sheathed in quartz sleeve 2.3 experimental work and analysis the continuous experiments procedure include a preparation of 6 l of aqueous solution with a desired concentration of ryellow dye at (ph= 7, h2o2= 400 mg/l, and tio2 =25 mg/l) which obtained from previous batch experiments .h2o2 in addition to tio2 has been added to the aqueous solution, then the solution was pumped from storage tank at the desired flow rate which is controlled by flow meter. the solution enters the rectangular pyrex glass reactor that had 10 l in volume with (19.5 × 19.5 × 26.5) cm 3 dimensions, from the bottom of tank and discharge as an overflow to another tank for treated water. the polluted water enters the tank from the bottom moves upward, until the discharging from the reactor leading to the full exposure of layers to the uv lamp. fig. 3 illustrates the photograph and the sketch of a continuous reactor. after each experiment, a sample was taken and analyzed by using (advanced microprocessor uv-vis spectrophotometer single beam li295) to measure the concentration of r-yellow dye at 420 nm. the removal efficiency (%) was obtained from following equation: the removal efficiency = (co-c)/co*100 (1) where: co = the initial concentration of dye in the aqueous solution (mg/l); c = the concentration (mg/l) after treatment. n. a.a. mohammed et al. / iraqi journal of chemical and petroleum engineering 21,2 (2020) 1 6 3 (a) (b) fig. 3. a, photograph of continuous reactor, b, schematic diagram of the reactor 3results and discussion 3.1. influence of initial dye concentration the effect of different initial r-yellow concentration (20, 50, 75 and 100)mg/l on the removal efficiency was studied at flow rate (5 l/h) and their results were plotted in fig. 4. the results showed that the removal efficiency of dye dropped with increasing dye concentration from 93.25% to 67.18% for (20 – 100 mg/l) of dye concentration. however, significant change in decolourization percentage was noticed beyond 20 mg/l. high decolorization may be at low concentrations because there are multiple active sites on the catalyst surface rather than the number of degrading dye molecules. [14], while increasing the concentration comes to saturation point and then excess dye is found in the reaction mixture. on the other hand, a decrease in decontamination in higher concentration of dye molecules didn’t allow enough light to penetrate through it to reach the catalyst surface (shadow effect). so the best initial concentration was 20 mg/l. this is in agreement with the finding of [15]. fig. 4. effect of initial dye concentration on the decolorization of r-yellow dye, ph= 7 [h2o2] = 400mg/l,[dye] = 20 mg/l, [tio2] = 25 mg/l 3.2. influence of flow rate the effect of different flow rate (5, 10 and 15) l/h on the removal efficiency of r-yellow dye was studied and their results were presented in fig. 5 , it can be seen from this figure that the maximum removal efficiency was (93.7%) at the flow rate 5 l/h . at high flow rate, the polluted wastewater was subjected to uv radiation in a short period of time that leads to decreases in the volume of provided energy for h2o2 to create additional hydroxyl radical [16]. an outcome given was that the rate of degradation of dye decreased with increasing the flow rate. this result was similar with the finding of [17]. fig. 5. effect of flow rate on the decolorization of yellow dye at ph= 7 [h2o2] = 400mg/l,[dye] = 20 mg/l, [tio2] = 25 mg/l 3.3. effect number of uv lamp fig. 6 shows the effect of different number of uv lamp at different flow rate on the removal efficiency of ryellow dye from aqueous solution while keeping other parameters constant from previous experiments; dye concentration=20 mg/l, h2o2=400 mg/l, tio2=25 mg/l, ph =7. n. a.a. mohammed et al. / iraqi journal of chemical and petroleum engineering 21,2 (2020) 1 6 4 the results show that the removal efficiency decreased with increasing flow rate while it increased by increasing number of uv lamp as can be seen in table 1 at 5 l/h flow rate .increasing the number of uv lamps will supply more energy for generation of hydroxyl radical, furthermore the reaction time was decreased, which will be considered the best effect factor in decolorization and degradation of dye [18]. this result was similar with the finding of [19] fig. 6. removal efficiency of r-yellow dye 20 mg/l with, one and two uv lamps, h2o2=400mg/l, tio2=25mg/l, ph=7 and flow rate = 5 l/h table 1. removal efficiency of r-yellow dye =20 mg/l by one uv and two uv, h2o2=400mg/l, tio2=25mg/l, ph=7and flow rate = 5 l/h in continuous system time 1 uv 2 uv 15 18.25 32.95 30 30.5 57.92 60 50 83.95 90 87.1 86.12 120 93.7 95.47 3.4. effect of irradiation intensity the influence of irradiation intensity (400 and 600) mw/cm 2 of (6 and 11) w uv lamp, respectively on the removal efficiency was plotted in figure (6). it can be seen from this figure that the degradation rate increases with increasing in uv light intensity from 93.7% to 96.8% for 6 and 11 w, respectively. uv irradiation supports generate the photons required to enhance the electron transfer from the valence band to the conduction band of a semiconductor photocatalyst, and as the energy of a photon is related to its wavelength, the overall energy input to a photocatalytic process turns out to be dependent on light intensity. the degradation rate increases when more radiation falls on the catalyst surface, hence, more hydroxyl radicals are produced [20]. this was similar with the finding of [21] fig. 7. effect of intensity of uv at dye=20mg/l, h2o2=400 mg/l, tio2=25 mg/l, ph=7, flow rates=5 l/h 3.5. kinetic studies on photocatalytic decolorization of dyes the experimental data for decolorization of the ryellow can be fitted according to pseudo-first-order and pseudo-second-order. the linearized form of pseudo-firstorder and second-order kinetic models can be given in equations (2) and (3): [22] 1 𝐶 − 1 𝐶𝑜 = 𝑘1𝑡 (2) 𝑘. 𝑡 = ln(𝐶𝑜 𝐶⁄ ) (3) where: k, k1 are the pseudo-firstand pseudo-secondorder rate constants in min -1 and l.mg -1 min -1 ,respectively, with respect to dye concentration; t is the irradiation time (in min); c is the dye concentration at time t; co : is the initial dye concentrationز a plot of (ln co/c), and (1/c -1\co) versus time for each experiment lead to a straight line whose slope is k and k1 respectively. the regression analysis of the concentration versus reaction time indicated that the rate of decomposition of the compound could be described by first order kinetics, as shown in table 2. table 2. reaction rate constants in heterogeneous photocatalyst h2o2=400mg/l, dye=20mg/l, ph=7, tio2=25 mg/l r 2 second order k1 l.mg -1 .min -1 r 2 first order k min -1 removal efficiency 0.8107 0.0328 0.98 0.0319 98.8 0.9002 0.0037 0.9750 0.0229 95.9 0.9766 0.0005 0.9593 0.0134 84.89 0.9951 0.0002 0.9273 0.0093 78.69 n. a.a. mohammed et al. / iraqi journal of chemical and petroleum engineering 21,2 (2020) 1 6 5 4conclusion reactive yellow dye removal using (h2o2/tio2/uv) process was examined. the results indicated that the h2o2/tio2/uv methods can be effective for the removal of textile wastewater, with a flow rate of (5-15) l/h and reaction time ranging from (10 – 120) min. however, the increase in the flow rate led to a decrease in the rate of decolorization. higher decolorization was required for a longer reaction time to generate a hydroxyl radical that could destroy the organic matter. maximum removal efficiency (93.7%) was achieved at ph 7 and at 400 mg/l of h2o2, 25 mg/l of tio2, 120 min of 1uv at 400 w irradiation and low flow rate by 5 l/hr. it is also worth highlighting that the r-yellow photo-degradation process appears to follow pseudo-first order kinetics, and that the rate constant is inversely proportional to the pollutant’s initial concentration level. references [1] grčića i., and koprivanaca n. (2018) photocatalytic oxidation of azo dyes and oxalic acid in batch reactors and cstr: introduction of photon absorption by dyes to kinetic models .chem. biochem. eng. q., 32 (1) 71–81. [2] w. taher mohammed, h. f. farhood, and a. hassoon bjaiyah al-mas’udi, “removal of dyes from wastewater of textile industries using activated carbon and activated alumina”, ijcpe, vol. 10, no. 1, pp. 43-52, mar. 2009. [3] i. faisal, “removal of dyes from polluted water by adsorption on maize cob”, ijcpe, vol. 11, no. 1, pp. 55-57, mar. 2010. [4] mahmoodi n. mohammad, arami m., limaee n. yousefi, tabrizi n. salman (2006) “kinetics of heterogeneous photocatalytic degradation of reactive dyes in an immobilized tio2 photocatalytic reactor”. journal of colloid and interface science 295,159–164. [5] reza, khan mamun, a. s. w. kurny, and fahmida gulshan. "parameters affecting the photocatalytic degradation of dyes using tio 2: a review." applied water science 7.4 (2017): 1569-1578. [6] f. m. hameed and k. m. mousa, “study on kinetic and optimization of continuous advanced oxidative decolorization of brilliant reactive red dye”, ijcpe, vol. 20, no. 1, pp. 9-14, mar. 2019. [7] krishnan, s., rawindran, h., sinnathambi, c. m., & lim, j. w. "comparison of various advanced oxidation processes used in remediation of industrial wastewater laden with recalcitrant pollutants." iop conf. ser. mater. sci. eng. vol. 206. no. 1. 2017. [8] huang, m., xu, c., wu, z., huang, y., lin, j., and wu, j.(2008) “photocatalytic discolorization of methyl orange solution by pt modified tio2 loaded on natural zeolite,” dye. pigment., vol. 77, no. 2, pp. 327–334. [9] zhiyong, yu, h. keppner, d. laub, e. mielczarski, j. mielczarski, l. kiwi-minsker, a. renken, and j. kiwi. "photocatalytic discoloration of methyl orange on innovative parylene–tio2 flexible thin films under simulated sunlight." applied catalysis b: environmental 79.1 (2008): 63-71. [10] senthilkumaar, s., k. porkodi, and r. vidyalakshmi. "photodegradation of a textile dye catalyzed by sol–gel derived nanocrystalline tio2 via ultrasonic irradiation." journal of photochemistry and photobiology a: chemistry 170.3 (2005): 225-232. [11] khan w., i. najeeb, and s. ishtiaque, (2016).“photocatalytic degradation of a real textile wastewater using titanium dioxide, zinc oxide and hydrogen peroxide,” int j eng sci, vol. 5, no. 7, pp.61– 70. [12] ali abd al hassan, 2017, “treatment of produced water by advanced oxidation processes”, m.sc., thesis, al-nahrain university college of engineering. [13] chaudhuri, m., elmolla, e. s. and othman, r., 2009," removal of reactive dyes from aqueous solution by adsorption coconut coir activated carbon", 2nd international conference on engineering technology (icet 2009), december, kuala lumpur. [14] saggioro e. m., oliveira a. s., thelma pavesi, cátia gil maia, et al.,(2011). “use of titanium dioxide photocatalysis on the remediation of model textile wastewaters containing azo dyes” .molecules ,vol.16, 10370-10386. [15] thamaraiselvi k., sivakumar t., brindha a. , and elangovan e. (2019). “photocatalytic degradation of reactive dyes over titanates”.journal of nanoscience and nanotechnology.vol. 19, 2087–2098. [16] mitrović, jelena, et al. "decolorization of textile azo dye reactive orange 16 with uv/h2o2 process." journal of the serbian chemical society 77.4 (2012): 465-481. [17] salman m. s., (2014). “advanced oxidation processes for the removal of reactive dyes from simulated wastewater”. ph.d. thesis, college of engineering, university of baghdad. [18] crittenden, john c., r. rhodes trussell, david w. hand, kerry j. howe, and george tchobanoglous. mwh's water treatment: principles and design. john wiley & sons, 2012. [19] qourzal, s., tamimi, m., assabbane, a. and aitichou, y. (2007) tio2 photocatalytic mineralization of β-naphthol: influence of some inorganic ions, ethanol, and hydrogen peroxide. comptes rendus chimie, 10, 1187-1194. [20] behnajady ma, modirshahla n, hamzavi r. kinetic study on photocatalytic degradation of c.i. acid yellow 23 by zno photocatalyst.( 2006). j hazard mater. b 133; 226–232. [21] muruganandham m. swaminathan, 2004. “photochemical oxidation of reactive azo dye with uv– h2o2 process”. dyes and pigments 62,269–275 . [22] swaminathan k., sandhya s., carmalin s. a., pachhade k., subrahmanyam v. y., (2003) “decolorization and degradation of h-acid and other dyes using ferrous–hydrogen peroxide system”, chemosphere , 50, pp. 619–625. https://hrcak.srce.hr/index.php?show=clanak&id_clanak_jezik=290543 https://hrcak.srce.hr/index.php?show=clanak&id_clanak_jezik=290543 https://hrcak.srce.hr/index.php?show=clanak&id_clanak_jezik=290543 https://hrcak.srce.hr/index.php?show=clanak&id_clanak_jezik=290543 https://hrcak.srce.hr/index.php?show=clanak&id_clanak_jezik=290543 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/397 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/397 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/397 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/397 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/397 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/369 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/369 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/369 https://www.sciencedirect.com/science/article/abs/pii/s0021979705008489 https://www.sciencedirect.com/science/article/abs/pii/s0021979705008489 https://www.sciencedirect.com/science/article/abs/pii/s0021979705008489 https://www.sciencedirect.com/science/article/abs/pii/s0021979705008489 https://www.sciencedirect.com/science/article/abs/pii/s0021979705008489 https://link.springer.com/content/pdf/10.1007/s13201-015-0367-y.pdf https://link.springer.com/content/pdf/10.1007/s13201-015-0367-y.pdf https://link.springer.com/content/pdf/10.1007/s13201-015-0367-y.pdf https://link.springer.com/content/pdf/10.1007/s13201-015-0367-y.pdf https://doi.org/10.31699/ijcpe.2019.1.2 https://doi.org/10.31699/ijcpe.2019.1.2 https://doi.org/10.31699/ijcpe.2019.1.2 https://doi.org/10.31699/ijcpe.2019.1.2 https://iopscience.iop.org/article/10.1088/1757-899x/206/1/012089/meta https://iopscience.iop.org/article/10.1088/1757-899x/206/1/012089/meta https://iopscience.iop.org/article/10.1088/1757-899x/206/1/012089/meta https://iopscience.iop.org/article/10.1088/1757-899x/206/1/012089/meta https://iopscience.iop.org/article/10.1088/1757-899x/206/1/012089/meta https://www.sciencedirect.com/science/article/abs/pii/s0143720807001283 https://www.sciencedirect.com/science/article/abs/pii/s0143720807001283 https://www.sciencedirect.com/science/article/abs/pii/s0143720807001283 https://www.sciencedirect.com/science/article/abs/pii/s0143720807001283 https://www.sciencedirect.com/science/article/abs/pii/s092633730700327x https://www.sciencedirect.com/science/article/abs/pii/s092633730700327x https://www.sciencedirect.com/science/article/abs/pii/s092633730700327x https://www.sciencedirect.com/science/article/abs/pii/s092633730700327x https://www.sciencedirect.com/science/article/abs/pii/s092633730700327x https://www.sciencedirect.com/science/article/abs/pii/s092633730700327x 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https://books.google.iq/books?hl=en&lr=&id=lslhaaaaqbaj&oi=fnd&pg=pr9&dq=%5b18%5d%09crittenden+john+c.,+r.+rhodes+trussell,+david+w.+hand,+kerry+j+howe+and+george+tchobanoglous&ots=p_ocoeu2jw&sig=gjspwomscxjsrpjytqkhdsjslhi&redir_esc=y#v=onepage&q=%5b18%5d%09crittenden%20john%20c.%2c%20r.%20rhodes%20trussell%2c%20david%20w.%20hand%2c%20kerry%20j%20howe%20and%20george%20tchobanoglous&f=false https://www.sciencedirect.com/science/article/pii/s1631074807001725 https://www.sciencedirect.com/science/article/pii/s1631074807001725 https://www.sciencedirect.com/science/article/pii/s1631074807001725 https://www.sciencedirect.com/science/article/pii/s1631074807001725 https://www.sciencedirect.com/science/article/pii/s1631074807001725 https://www.sciencedirect.com/science/article/abs/pii/s0304389405006412 https://www.sciencedirect.com/science/article/abs/pii/s0304389405006412 https://www.sciencedirect.com/science/article/abs/pii/s0304389405006412 https://www.sciencedirect.com/science/article/abs/pii/s0304389405006412 https://www.sciencedirect.com/science/article/abs/pii/s0143720803002572 https://www.sciencedirect.com/science/article/abs/pii/s0143720803002572 https://www.sciencedirect.com/science/article/abs/pii/s0143720803002572 https://www.sciencedirect.com/science/article/abs/pii/s004565350200615x https://www.sciencedirect.com/science/article/abs/pii/s004565350200615x https://www.sciencedirect.com/science/article/abs/pii/s004565350200615x https://www.sciencedirect.com/science/article/abs/pii/s004565350200615x https://www.sciencedirect.com/science/article/abs/pii/s004565350200615x n. a.a. mohammed et al. / iraqi journal of chemical and petroleum engineering 21,2 (2020) 1 6 6 المتقدمةازالة الصبغة التفاعلية الصفراء باستخدام المفاعل المستمر لعمليات االكسدة 2و محمد سلمان 1, عبير الورد1نور عبداالمير محمد جامعة بغداد/كلية الهندسة/قسم الهندسة البيئية1 جامعة بغداد/مركز ابن سينا للتعليم االلكتروني2 الخالصة تهدف هذه الدراسة الى استخدام مفاعل التحفيز الضوئي الزالة الصبغة الصفراء الفعالة من المحاليل المائية كمحفز ضوئي كما و تمت هذه العملية بدرجة حرارة الغرفة وبوجود tio2كما تضمنت التجربة استعمال مادة تضمن البحث دراسة اآلثار التآزرية لعوامل مثل معدل التدفق ، وعدد (uv)مصباح لألشعة فوق البنفسجية 7وكثافة مصابيح األشعة فوق البنفسجية في مفاعل التحفيز الضوئي المستمر بثبات الـدالة الحامضية عند ال ملغ / لتر.، تم التوصل الى h2o2 =400مجم / لتر( وتركيز بيروكسيد الهيمروجين 25=) tio2وتركيز دقيقة و باستخدام مصباحين من األشعة فوق البنفسجية و تركيزالصبغة 60الحد االعلى لنسب االزالة عندان بينت الدراسة وجود تطابق جيد بين النتائج العملية ، كما )٪95.4لتر / ساعة بلغت) 5لتر وبمعدل تدفق 20 موديل التفاعل الحركي االول والنظرية المستحصله من موديل االمتزاز في تجارب الحركية عند استخدام , معالجة مياهئي, العامل المساعد غير المتجانسالتحلل الضو ,: الصبغة الصفراء التفاعليةالدالةالكلمات iraqi journal of chemical and petroleum engineering vol.12 no.4 (december 2011) 5-20 issn: 1997-4884 laminar free convection in three dimensional inclined porous annulus with fins on the inner cylinder saad m. al-mashaat and manal h. al-hafidh university of baghdad abstract an experimental and numerical study was carried out to investigate the heat transfer by natural convection in a three dimensional annulus enclosure filled with porous media (silica sand) between two inclined concentric cylinders with (and without) annular fins attached to the inner cylinder under steady state condition. the experiments were carried out for a range of modified rayleigh number (0.2 ≤ra * ≤ 11) and extended to ra * =500 for numerical study and for annulus inclination angle of (δ = 0˚, 30˚, 60˚ and 90˚). the numerical study was to give the governing equation under assumptions that used darcy law and boussinesq’s approximation and then it was solved numerically using finite difference approximation. it was found that the average nusselt number depends on (ra * , hf, δ and rr ). the results showed that the increasing of the fin length increases the heat transfer rate for any fin pitch unless the area of the inner cylinder exceeds that of the outer one; then the heat will be stored in the porous media. a comparison was made between the results of the present work and those of other researches for the case without fins and excellent agreement was obtained. :الخالصة أجريت في هذا البحث دراسة عملية ونظرية إلنتقال الطاقة الحرارية بالحمل الحر في فجوة حلقية ثالثية األبعاد ل( بين أسطوانتين مائلتين متحدتي المركز بوجود )وعدم وجود( زعانف متصلة مملؤة بوسط مسامي)رم *ra ≥ 0.2)باإلسطوانة الداخلية تحت شروط حالة اإلستقرار. أجريت التجارب العملية لمدى عدد رالي المعّدل تم كتابة (.˚δ = 0˚, 30˚, 60˚ and 90) في الجزء النظري ولزاوية ميل ra*= 500ولمدى (11≥ بداللة معادلة الى وتحويلها بوسنسك تحت فرضيات قانون دارسي وتقريبالمعادالت الحاكمة في الدراسة النظرية الفروق المحددة. تتضمن إمكانية الحل العددي حساب طريقة باستخدام حلت عدديا اھبدور والتي المتجه الجهد متوسط. بينت النتائج أن عدد نسلت المتوسط يعتمد على الجهد المتجه ودرجة الحرارة وعدد نسلت الموقعي وال عدد رالي المعّدل وطول الزعنفة وزاوية ميل األسطوانة ونسبة األقطار, بينت النتائج أن زيادة طول الزعنفة ألي على خطوة زعنفة يسبب زيادة في أنتقال الطاقة الحرارية إال في حالة زيادة المساحة السطحية لألسطوانة الداخلية تلك التي لألسطوانة الخارجية فإن ذلك يتسبب في خزن الطاقة الحرارية في الوسط المسامي. قورنت النتائج للبحث الحالي مع نتائج بحوث أخرى في حالة عدم وجود زعانف وأعطت توافق جيد. key words: natural convection, three dimensional, inclined annulus, porous media and annular fins. iraqi journal of chemical and petroleum engineering university of baghdad college of engineering laminar free convection in three dimensional inclined porous annulus with fins on the inner cylinder 6 ijcpe vol.12 no.4 (december 2011) available online at: www.iasj.net introduction in recent years, natural convection in a cylindrical annulus has attracted much attention in relation to solar collectors, thermal storage systems and spent nuclear fuel cooling. a review of the works concerning this configuration was presented by kuehn and goldstein [l]. however, most of them were for horizontal concentric cylinders with infinite axial length. in this case, a two-dimensional (2-d) analysis is allowed because the convective flow is confined to the vertical plane and the flow pattern is identical in each annular cross section. on the other hand, a three dimensional (3-d) treatment is unavoidable in the horizontal case with the finite axial length and the rigid axial boundary surfaces and/or in the case when the cylinders are inclined from the horizon, because the viscous shearing force at the end walls and/or the gravitational force have an effect on the convection toward the axial direction fukuda [1]. in the 3-d numerical analysis, the matrix to be dealt with is far larger than that in the 2-d case, taking more cpu time to obtain the solution. recently it has become feasible to treat this problem due to improvements in processing speed and memory capacity of digital computers. several numerical works have been performed, most of them for rectangular enclosures. numerical analysis has been performed by fukuda [1] on three dimensional natural convection enclosed with concentric inclined cylinders. governing equations were numerically solved by means of over – relaxation method for ranges of rada (a product of rayleigh number ra and darcy number da) from 1 to 1000 and an angle of inclination of cylinders from the horizon of 0 to π/2. results showed that the local nusselt number on the inner cylinder wall has its maximum value at bottom end, while nusselt number on the outer cylinder wall has its maximum value at top end. however, the average nusselt number depends largely on only rada and is hardly affected by the inclination. bogdan [2] presented experimental and numerical work investigating the effect of metallic porous materials, inserted in a pipe, on the rate of heat transfer. the pipe is subjected to a constant and uniform heat flux. the effects of porosity, porous material diameter and thermal conductivity as well as reynolds number on the heat transfer rate and pressure drop are investigated. the results are compared with the clear flow case where no porous material was used. it is shown that for an accurate simulation of heat transfer when a porous insert is employed its effective thermal conductivity should be carefully evaluated. ramón [3] numerically investigated three-dimensional natural convection of air in a cubical enclosure with a fin on the hot wall for rayleigh numbers of 10 3 –10 6 . the fin, with a thickness of 1/10 of the cavity side, is placed horizontally on the hot wall. the solid to fluid thermal conductivity ratio (rk) and the fin width are varied. because the fin is shorter than the cavity side, the cold flow sweeps the lower fin face and the hot wall at the clearances between the fin sides and the lateral walls, where high vertical velocities are reached. the fin inhibits the frontal and lateral access of fluid to the upper fin face, especially at low rayleigh numbers. low values of rk cause heat transfer reductions. the contribution of the fin faces increases at high rk causing heat transfer enhancements above 20%, which exceed the ones obtained in most two-dimensional studies. in the range of ra from 10 5 to 10 6 , maximum heat transfer rates are found for dimensionless fin widths of 0.6 and 0.8 respectively. it is saad m. al-mashaat and manal h. al-hafidh available online at: www.iasj.net ijcpe vol.12 no.4 (december 2011) 7 concluded that for 10 5 ≤ ra ≤ 10 6 a fin of partial width is more effective in promoting heat transfer than a fin of full width. experimental study three outer cylinders of different diameters were manufactured to vary the radius ratio and to vary the fin length; ten inner cylinders were manufactured one without fins and the others with different fin length(hf =3mm, 7mm and 11mm), radius ratios of (rr=(r1/r2) = 0.293, 0.364 and 0.435), number of fins (n=12, 23 and 45) and pitch length of (s = 19.2mm, 8.4mm and 3mm) to investigate the effect of these parameters and the effect of modified rayleigh number by the variation of the temperature difference between the two concentric cylinders by means of a variable electric input power. aluminum was chosen because of its high thermal conductivity and easy machinability. the test section consists of a three aluminum outer cylinders of (100 mm), (82 mm) and (70 mm) outside diameters, (4 mm) thick and (260mm) long to which ten aluminum inner cylinders of (27mm) outside diameter, (260 mm) long and (5 mm) thick. the inner cylinder was heated by passing an alternating current to a heater inside the inner cylinder and the outer cylinder was subjected to the surrounding temperature (freezer) where the minimum temperature was 270 k. the inner cylinder surface temperatures were measured at six locations using thermocouples type ( k). the experimental apparatus is shown diagrammatically in fig. 1 mathematical model the schematic drawing of the geometry and the cartesian coordinate system employed in solving the problem is shown in fig. 2. fig.1, schematic diagram of experimental apparatus (a) (b) fig. 2, (a) geometry and coordinates system and (b) schematic diagram of inner cylinder with 8.4mm pitch in order to model the incompressible flow in the porous medium, the steadystate equations of the darcy flow laminar free convection in three dimensional inclined porous annulus with fins on the inner cylinder 8 ijcpe vol.12 no.4 (december 2011) available online at: www.iasj.net model, namely, the mass, the momentum (darcy), the energy conservation laws and the boussinesq's approximation are employed. these equations in vectorial notation are given by nield and bejan [4] and fin equation by ramón [3]. governing equations the conservation equations of mass, momentum and energy in steady state and the supplementary equation are fukuda [1]:    22 1 tt   (1) where: t      1 (2) is the thermal coefficient of the volume expansion; this constant is evaluated at t2 which is the temperature at the inner surface of the outer cylinder, ρ2 is the density at t2 and ρ is the density at t, fukuda [1]. this technique is called boussinesq's approximation. mass conservation 0 1          z uu rr u r u zrr   (3) momentum equations the most common model used for flow in the porous media is the darcy flow model. darcy’s law states that the volume average velocity through the porous material is proportional with the pressure gradient. in three dimensional flows, the darcy’s model wang [5] is: momentum equation in radial direction             coscosg r pk u f r (4) momentum equation in angular direction              cossin 1 g p r k u f (5) momentum equation in axial direction             sing z pk u f z (6) energy equation                                                   2 2 2 2 2 11 z tk tk rr tk r rr tc z utc r u tc r u t tc pzp pr p (7) where  is viscous dissipation function. fin equation within the fin itself, the energy equation is ramón [3]: 0 1          z tt rr t r t  (8) following aziz [6] a vector potential  with its components:  ),, zr    defined by:  .eff u  (9) z uu r z r          12 (10) r u z u zr        2 (11)            r z u rr ru r 112 (12) non dimensional variables the characteristic length for the present study is r2 fukuda [1] to convert the governing equations to the dimensionless form, the dimensionless magnitudes must be defined as follow: saad m. al-mashaat and manal h. al-hafidh available online at: www.iasj.net ijcpe vol.12 no.4 (december 2011) 9 2 r r r  , 2 r z z  , m r r lu u   , eff lu u     , .eff z z lu u   ,     212 / tttt  , 2 r lkp p feff        .1221 / eff rrttkgra   , 2 1 2 r s s  , 2 2 2 r t s s   2 1 r h h f  substitute these dimensionless magnitudes in the governing equations. alternative expressions of eq. (3) may be written in terms of :, asand zr               zr u z r    1 (13)             rz u zr   (14)                  r z r rr u 1 (15) taking curl of momentum equations to eliminate pressure terms, the momentum equations will be:                zrrr l ra      cossinsin 1 12   zrz rrrr r rr zr rrrr                      2 121 2 2 2 2 222 2 (16)                rzrr l ra     sincoscos 12 rrrr rrz r                       12 1 22 2 2 22 2 2 2 (17)                    rrrr l ra      sincos 1 cos 12 2 2 2 2 22 2 11 zrrrr zzzz                (18) the vector potential equation was obtained in the dimensionless form as   zrz rrr r r rr zr rr r r r                        2 12 1 2 2 2 2 2 22 2 2 (19) rrrr rrz r                         12 1 2 2 2 22 2 2 2 2 2 (20) 2 2 2 2 2 2 2 2 1 1 zr rrr zz zz z                  (21) and the energy equation will be: laminar free convection in three dimensional inclined porous annulus with fins on the inner cylinder 10 ijcpe vol.12 no.4 (december 2011) available online at: www.iasj.net ] 11 [ 1 11 2 2 2 2 22 2 1 zrrrrr l zrrr rzrrzr r zrz                                                                      (22) and the fin equation will be: 0 1          zrrr    (23) dimensionless hydraulic boundary conditions for the vector potential field, the boundary conditions are given as:   1,0 1 1 rratr rr zr           ,00     at zr lzat z z r ,00        and for the fin, the boundary conditions are given as:   0 1          z r rr z r      on the fin faces which were located on the following planes at r = r1 for  = 0, π (fin base) as in fig. 3 at r = r1+hf for  = 0, π (fin tip) at andranyforsands 21 fig. 3, fin boundary conditions dimensionless thermal boundary conditions for the temperature field, the dimensionless thermal boundary conditions are: 211 /1 rrrrat  10 2  rrat    ,00    at lzat z ,00    mediumefffinfin r k r k hrat         . 1 mediumefffinfin z k z k andranyatsat andranyatsat          . 2 1 mediumefffinfin kk ranyandat             . ,0 where: keff. =the effective thermal conductivity of the medium (w/mk).   fsef kkk   1 (24) computational technique equations (16, 17, 18, 22 and 23) were transformed into the finite difference equations, where the upwind differential method in the left hand side of the energy eq. (22) and the centered – space differential method for the other terms were used, and solved by using (sor) method wang [5]. a computer program was built using fortran 90 language to meet the requirements of the problem. the value of the vector potential  will be calculated at each node, in which the value of vector potential is saad m. al-mashaat and manal h. al-hafidh available online at: www.iasj.net ijcpe vol.12 no.4 (december 2011) 11 unknown, the other node will appear in the right hand side of each equation. as an initial value of iteration, zero is chosen for the vector potential field, while a conduction solution is adopted for temperature field. the index (n) was used to represent the nth – approximation of temperature denoted by n and substituted into the approximated equations, which were solved to obtain the nth – approximation of vector potential  , then  was substituted into eq. (22) to obtain 1n . a similar procedure is repeated until the prescribed convergence criterion given by inequality: 8 1 10     n nn max   was established fukuda [1]. as the steps of iteration increase with ra * , a solution obtained for lower ra * was used as an initial value of computation for higher ra * (double iteration method). it is clear that as the grid becomes finer, the convergence of the results becomes better. the number of grid points used was 21 grid points in the r – direction, 31 in the  – direction and 301 in the z – direction which seems reasonable and will be used in the present study. fig. 4 illustrate the numerical grid in two planes. (a) horizontal (r – ϕ) plane (b) vertical (r – z) plane fig. 4, numerical grid calculation of local and average nusselt number nusselt number is the dimensionless parameter indicative of the rate of energy convection from a surface and can be obtained as follows fukuda [1]:     21 12 ttk rrq nu    (25) as the local heat flux on the wall is given by: r t kq    (26) the local nusselt number nu1 and nu2 on the inner and the outer cylinders are written in the form fukuda [1]:   1 11 1 rr r rnu            (27)   11 12 1           r r rnu  (28) the average nusselt number nuin and nuout on the inner and the outer cylinders are defined as:               l rr in dzd rl rnu 0 0 1 1 1     (29)               l r out dzd rl rnu 0 0 1 1 1 1     (30) laminar free convection in three dimensional inclined porous annulus with fins on the inner cylinder 12 ijcpe vol.12 no.4 (december 2011) available online at: www.iasj.net results and discussion figs. 5 to 8 show the variation of the average nusselt number on the hot cylinder with ra * for different radius ratios, without and with fins respectively. these figures show that for any radius ratio, the average nu is generally constant for low values of ra * then as ra * reached nearly 100, nu increased with increasing ra * . these values increased as rr decreased due to the enlarge of the distance between the two cylinders. for low values of ra * , the maximum values of nu was for maximum rr until ra * reached nearly 100, then the situation would inverse and the maximum values of nu would be for minimum rr which improved that for low values of ra * the heat transferred by conduction and as ra * increased the convection heat transfer and that would be the dominant. these figures show as ra * exceeds 100, as hf increases nu decreases and decreasing the pitch (by increasing fin numbers) causes nu to decrease. fig. 9 illustrates that the values of the average nusselt number was low for high radius ratio; then they increased with high intensity as radius ratio decreased. when the annulus gap decreased, the resistance to the circulation motion of the convection cells increased and this lead to slower replacement of the hot air adjacent to the inner surface by the cold air adjacent to the outer surface and these resulted in an increase in the average temperature of the annulus inner surface and consequently in a decrease in the rate of heat transfer. it is clear that the curves of the different radius ratios converge to each others as ra * decreases; this means that the effect of radius ratio on the rate of heat transfer decreases with decreasing ra * . this can be attributed to that as ra * decreases the heat convection becomes insignificant, or in other words, heat conduction becomes the dominant heat transfer in the fluid layer. convective heat transfer rate is controlled by three parameters (h, a and δt), according to     2121 ttahttahq outoini  for the same modified rayleigh number (i.e. δt is constant), dq/q=(da/a)+(dh/h). if the increase in the surface area is more than the decrease in the heat transfer coefficient (average nu), the total heat transfer rate will increase, or if the decrease in the heat transfer coefficient is more than the increase in the surface area, the total heat transfer rate will decrease harith [7]. fig. 10 indicates that there is a reduction in the average nusselt number with increasing hf from 3mm to 11mm. for the same value of ra * , reduction in the average nusselt number may be ranged between (18% to 38 %). figs. 11 to 13 indicate that there is a reduction in the average nusselt number with increasing the number of fins from n=12(pitch=19.2mm) to n=23(pitch=8.4 mm) and then to n=45(pitch=3mm) with the increasing of inclination angle, radius ratio and fin length. the distribution of the local nusselt number are shown in fig. 14.the peak of the local nu on the outer cylinder wall generally appeared at a position of z=l (at the top) and ϕ with some deviation from π. while for the inner cylinder the peak appeared at a position of z=0 (bottom of the cylinder). saad m. al-mashaat and manal h. al-hafidh available online at: www.iasj.net ijcpe vol.12 no.4 (december 2011) 13 fig. 5, variation of average nusselt number with ra * on the hot cylinder for n=0 and for different values of rr and δ fig. 6, variation of average nusselt number with ra * on the hot cylinder for n=12, hf=3mm and for different rr, δ 0 5 10 15 20 25 30 0.5 5 20 60 100 300 500 ra n u a v e ra g e rr=0.435 =0.338 =0.225 =0.169 =0.135 0 5 10 15 20 25 0.5 5 20 60 100 300 500 ra n u a v e ra g e rr=0.435 =0.338 =0.225 =0.169 =0.135 0 2 4 6 8 10 12 14 16 18 20 0.5 5 20 60 100 300 500 ra n u a v e ra g e rr=0.435 =0.338 =0.225 =0.169 =0.135 0 2 4 6 8 10 12 14 0.5 5 20 60 100 300 500 ra n u a v e ra g e rr=0.435 =0.338 =0.225 =0.169 =0.135 0 5 10 15 20 25 0.5 1 5 10 20 40 60 80 100 200 300 400 500 ra n u a v e ra g e rr=0.435 =0.338 =0.225 =0.169 =0.135 0 2 4 6 8 10 12 14 16 18 20 0.5 5 20 60 100 300 500 ra n u a v e ra g e rr=0.435 =0.338 =0.225 =0.169 =0.135 0 2 4 6 8 10 12 14 16 0.5 1 5 10 20 40 60 80 100 200 300 400 500 ra n u a v e ra g e rr=0.435 =0.338 =0.225 =0.169 =0.135 0 1 2 3 4 5 6 7 8 9 10 0.5 5 20 60 100 300 500 ra n u a v e ra g e rr=0.435 =0.338 =0.225 =0.169 =0.135 laminar free convection in three dimensional inclined porous annulus with fins on the inner cylinder 14 ijcpe vol.12 no.4 (december 2011) available online at: www.iasj.net hf 7mm, hf 7mm, hf 11mm, hf 11mm, fig. 7, variation of average nusselt number with ra * on the hot cylinder for n=12and for different rr and δ n 2 , n 2 , n=45, n 45, fig. 8, variation of average nusselt number with ra * on the hot cylinder for hf=11mm and for different rr 0 2 4 6 8 10 12 14 16 0.5 5 20 60 100 300 500 ra n u a v e ra g e rr=0.435 =0.338 =0.225 =0.169 =0.135 0 2 4 6 8 10 12 0.5 5 20 60 100 300 500 ra n u a v e ra g e rr=0.435 =0.338 =0.225 =0.169 =0.135 0 2 4 6 8 10 12 14 0.5 5 20 60 100 300 500 ra n u a v e ra g e rr=0.435 =0.338 =0.225 =0.169 =0.135 0 1 2 3 4 5 6 7 8 9 10 0.5 5 20 60 100 300 500 ra n u a v e ra g e rr=0.435 =0.338 =0.225 =0.169 =0.135 0 1 2 3 4 5 6 7 8 0.5 5 20 60 100 300 500 ra n u a v e ra g e rr=0.435 =0.338 =0.225 =0.169 =0.135 0 1 2 3 4 5 6 0.5 5 20 60 100 300 500 ra n u a v e ra g e rr=0.435 =0.338 =0.225 =0.169 =0.135 0 0.5 1 1.5 2 2.5 3 3.5 0.5 5 20 60 100 300 500 ra n u a v e ra g e rr=0.435 =0.338 =0.225 =0.169 =0.135 0 0.5 1 1.5 2 2.5 3 0.5 5 20 60 100 300 500 ra n u a v e ra g e rr=0.435 =0.338 =0.225 =0.169 =0.135 saad m. al-mashaat and manal h. al-hafidh available online at: www.iasj.net ijcpe vol.12 no.4 (december 2011) 15 n=12 n=23 n=45 fig. 9, variation of average nusselt number with rr for hf=7mm δ =30 and for different ra * fig. 10, variation of average nusselt number with rr for ra * =500, n=12 and for different hf and δ -1 4 9 14 19 24 0 0.2 0.4 0.6 rr n u a v e ra g e ra=1, cold wall ra=1, hot wall ra=10, cold wall ra=10, hot wall ra=100, cold wall ra=500, cold wall ra=500, hot wall -1 1 3 5 7 9 11 13 15 0 0.2 0.4 0.6 rr n u a v e ra g e ra=1, cold w all ra=1, hot w all ra=10, cold w all ra=10, hot w all ra=100, cold w all ra=100, hot w all ra=500, cold w all ra=500, hot w all -1 1 3 5 7 9 11 0 0.2 0.4 0.6 rr n u a v e ra g e ra=1, cold w all ra=1, hot w all ra=10, cold w all ra=10, hot w all ra=100, cold w all ra=100, hot w all ra=500, cold w all ra=500, hot w all 0 1 2 3 4 5 6 0 0.2 0.4 0.6 rr n u a v e r a g e ra=1, cold w all ra=1, hot w all ra=10, cold w all ra=10, hot w all ra=100, cold w all ra=100, hot w all ra=500, cold w all ra=500, hot w all 0 5 10 15 20 25 0.135 0.169 0.225 0.338 0.435 rr n u a v e r a g e hf =3 mm hf =7 mm hf =11mm w ithout f ins 0 5 10 15 20 25 0.135 0.169 0.225 0.338 0.435 rr n u a v e r a g e hf =3 mm hf =7 mm hf =11mm w ithout f ins 0 2 4 6 8 10 12 14 0.135 0.169 0.225 0.338 0.435 rr n u a v e ra g e hf =3 mm hf =7 mm hf =11mm w ithout f ins 0 2 4 6 8 10 12 14 16 18 20 0.135 0.169 0.225 0.338 0.435 rr n u a v e ra g e hf =3 mm hf =7 mm hf =11mm w ithout f ins laminar free convection in three dimensional inclined porous annulus with fins on the inner cylinder 16 ijcpe vol.12 no.4 (december 2011) available online at: www.iasj.net ra * =500 ra * =1 fig. 11, variation of average nusselt number with δ for rr=0.435 and for different n and hf ra * =500 ra * =10 fig. 12, variation of average nusselt number with rr for δ =0, hf=11mm and for different n and ra fig. 13, variation of average nusselt number with hf and for rr=0.135 and different n and ra * fig. 15 illustrate the relation between the average nusselt number and modified rayleigh number for different rr and δ for n=12 and hf=3mm. the average nusselt number was nearly constant because of the predominance of conduction mode on heat transfer process. for ra * ˃100 (in the numerical part) convection became predominant mechanism and the average nusselt number began to clearly increase. most of the experimental values were lower than that of the numerical; one 0 5 10 15 20 25 30 0 20 40 60 80 100 n u a v e ra g e n=12, hf =3 mm hf =7 mm hf =11mm n=23, hf =3 mm hf =7 mm hf =11mm n=45, hf =3 mm hf =7 mm hf =11mm w ithout f ins 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 0 20 40 60 80 100 n u a v e ra g e n=12, hf =3 mm hf =7 mm hf =11mm n=23, hf =3 mm hf =7 mm hf =11mm n=45, hf =3 mm hf =7 mm hf =11mm w ithout f ins 0 5 10 15 20 25 30 0 0.2 0.4 0.6 0.8 1 rr n u a v e ra g e n=12 n=23 n=45 w ithout f ins 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 0 0.2 0.4 0.6 0.8 1 rr n u a v e ra g e n=12 n=23 n=45 w ithout f ins 0 2 4 6 8 10 12 14 16 18 20 0 5 10 15 hf (mm) n u a v e ra g e n=12 ra=10 ra=100 ra=500 n=23 ra=10 ra=100 ra=500 n=45 ra=10 ra=100 ra=500 0 1 2 3 4 5 6 7 8 9 0 5 10 15 hf (mm) n u a v e ra g e n=12 ra=10 ra=100 ra=500 n=23 ra=10 ra=100 ra=500 n=45 ra=10 ra=100 ra=500 saad m. al-mashaat and manal h. al-hafidh available online at: www.iasj.net ijcpe vol.12 no.4 (december 2011) 17 of the reasons may be the conduction losses through the sides and hence the absence of perfectly insulated ends boundaries and may be because of the assumptions which had been taken and this is true even for this research or for [prasad and kulacki 1985] and [havstad and burns 1982] . a comparison for the variation of the average nusselt number on the inner and outer cylinders with ra * was made with that of fukuda[1] in fig. 16 and its clear that nu is constant for low values of ra * , until ra * equal nearly 100, then nu will increase with the increasing of ra * as presented in this work. n=0 n=12, hf=3mm n=12, hf=7mm n=12, hf=11mm fig. 14, the distribution of local nusselt number in ϕ and z – direction for ra * =100 and δ=0 fia0 50 100 150 z 0 50 100 150 200 250 n u 1.5 2 2.5 3 3.5 3.4 3.4 3 2.6 1.4 2.62.6 2.2 1.4 2.22.22.2 3.4 1.8 3.4 1.8 2.6 3.4 1.4 3.43.43.43.4 1.4 2.62.6 33 1.8 2.6 3 1.8 2.6 1.4 2.2 1.8 3 1.4 2.2 3.43.4 2.2 2.6 1.8 2.6 3.4 1.8 3 2.2 1.8 3 1.4 3.4 2.6 3 1.8 3.4 2.2 3.4 3 2.6 1.8 2.6 3 2.2 fia0 50 100 150 z 0 50 100 150 200 250 n u 1.5 2 2.5 3 3.5 4 2.2 3.8 3 1.8 3 2 .6 2 .62.6 3.4 3 3 .4 2.2 2 .6 1.4 3 2.2 3 2.2 2.6 1.4 3 .8 33 1.8 1.4 3 1.8 2.62.6 1.8 1.8 3.8 3.4 3 1.4 3 .8 3 3.8 3.4 2.6 3 .8 3 .4 3 .8 2.2 2.22.2 3 .4 3 2.6 3 3 .4 3 3.4 2.6 3 1.8 2.2 2.6 1.8 2.2 3 2.2 2.6 3.8 2.6 33 1.4 2.2 3 3.8 2.6 3.4 2.2 1.4 2.2 1.4 fia0 50 100 150 z 0 100 200 n u 1.5 2 2.5 3 3.5 4 4 3.6 3.2 2 .42.4 2 .4 1.6 2 3.2 1.6 2.8 1 .6 2 .8 2 .4 3.6 2 3.2 1.6 1 .6 2 3 .2 2 .8 1.6 2.8 3 .6 3.6 2 2.8 4 3 .2 2 3.2 1.6 2.4 2 .8 1 .6 2 .4 2 3.6 2.8 3.2 1.6 2.4 2 1 .6 3.63.6 3.2 2.8 22 3 .2 2 .4 3.6 3.23.2 3.2 2.8 2 3 .2 4 2 .8 4 2 .4 3 .2 3.6 3.6 2.82.82.8 2 .8 3.6 3.23.2 1.61.6 fia 0 50 100 150 z 0 100 200 n u 2 3 4 2.8 4 3.2 2 .4 4 3.6 2.4 4 3.2 3.6 2 3.2 3.2 4.4 4 4 2 3.2 4 3 .2 4 2.8 2.4 4 3.63.6 2.8 2.4 4 3.23.2 2.82.8 nu nu nu nu laminar free convection in three dimensional inclined porous annulus with fins on the inner cylinder 18 ijcpe vol.12 no.4 (december 2011) available online at: www.iasj.net fig. 15, variation of average nusselt number with modified ra for different rr and δ for n=12, hf =3mm fukuda[1] present work fig. 16, a comparison for the variation of the average nusselt with ra * for fukuda[1] with that of the present work respectively conclusions the following major conclusions can be drawn from the experimental and numerical study: 1average nu number increases with increasing fin length at the same ra * and fin number unless the surface area of the inner cylinder exceeds that of the outer cylinder, then the heat will be stored in the porous media. 2there is a reduction in the average nusselt number with increasing the number of fins and with the increasing of inclination angle, radius ratio and fin length. 3for all parameters, results showed that the average nu number increases with an increase in modified rayleigh number and 1 1.2 1.4 1.6 1.8 2 2.2 2.4 0 5 10 15 ra a v e ra g e n u ( h o t w a ll ) as=0.293 experimental as=0.365 experimental as=0.435 experimental theoretical 1 1.2 1.4 1.6 1.8 2 2.2 2.4 0 5 10 15 ra a v e ra g e n u ( h o t w a ll ) as=0.293 experimental as=0.365 experimental as=0.435 experimental theoretical 1 1.2 1.4 1.6 1.8 2 2.2 2.4 0 2 4 6 ra a v e ra g e n u ( h o t w a ll ) as=0.293 experimental as=0.365 experimental as=0.435 experimental theoretical 1 1.2 1.4 1.6 1.8 2 2.2 2.4 0 5 10 15 ra a v e ra g e n u ( h o t w a ll ) as=0.293 experimental as=0.365 experimental as=0.435 experimental theoretical 0 5 10 15 20 25 0.5 1 5 10 20 40 60 80 100 200 300 400 500 ra n u a v e ra g e rr=0.435 =0.338 =0.225 =0.169 =0.135 saad m. al-mashaat and manal h. al-hafidh available online at: www.iasj.net ijcpe vol.12 no.4 (december 2011) 19 hardly affected by δ for low values of ra * . 4increasing rr cause a clearly increase in average nusselt number for ra * ˃ 100. 5the peak of the local nu on the outer cylinder wall generally appeared at a position of z=l (at the top) and ϕ with some deviation from π. while for the inner cylinder the peak appeared at a position of z=0 (bottom of the cylinder). references 1fukuda k., takata y., hasegawa s., shimomura h. and sanokawa k., “three – dimensional natural convection in a porous medium between concentric inclined cylinders”, proc. 19 th natl heat transfer conf., vol. htd – 8, pp. 97 – 103, 1980. 2bogdan i. pavel and abdulmajeed a. mohamad, 2004 “an experimental and numerical study on heat transfer enhancement for gas heat exchangers fitted with porous media”, int. j. of heat and mass transfer vol. 47, pp. 4939– 4952. www.elsevier.com. 3ramón l. f. and sergio g. m., 2007 “three dimensional natural convection in finned cubical enclosure”, int. j. of heat and fluid flow. vol. 28, pp. 289-298. 4nield d. a. and bejan a., 1999 “convection in porous media”, springer-verlag, new york. 5wang bu – xuan and zhang xing, 1990 “natural convection in liquid saturated porous media between concentric inclined cylinders” int. j. heat and mass transfer vol. 33. no 5, pp. 827-833. 6aziz k. and hellums j. d., 1967 “numerical solution of the three dimensional equations of motion for laminar natural convection”, the physics of fluids, v0l. 10, no. 2, pp. 314 – 324. 7harith h. h., 2009 “an investigation of fins geometry effects for laminar free convection in horizontal annulus with finned inner cylinder”, msc thesis, university of baghdad. 8prasad, v. and kulacki, f. a., “natural convection in porous media bounded by short concentric vertical cylinders”, transaction of asme, j. of heat transfer , vol. 107, pp. 147-154, february, 1985. 9havstad m.a., burns p.j.," convective heat transfer in vertical cylindrical annuli filled with a porous medium", int. j. heat and mass transfer, vol. 25, no.11, pp. 1755-1766, 1982 nomenclature greek symbols symbol description unit  thermal diffusivity m 2 /s  volumetric thermal expansion coefficient 1/k δ angle of inclination degree θ dimensionless temperature υ kinematic viscosity of fluid m 2 /s μf dynamic viscosity of fluid n.s/m 2 http://www.elsevier.com/ laminar free convection in three dimensional inclined porous annulus with fins on the inner cylinder 20 ijcpe vol.12 no.4 (december 2011) available online at: www.iasj.net latin symbols symbol description unit cp specific heat at constant pressure j/ g c fia φ in fig. 13 g acceleration due to gravity m/s 2 hf fin length m kf thermal conductivity of the fluid w/m k ks thermal conductivity of the solid w/m k keff. effective thermal conductivity of the porous media w/m k k permeability m 2 l cylinder length m l dimensionless cylinder length nu1 local nusselt number on the inner cylinder nu2 local nusselt number on the outer cylinder p pressure n/m 2 q local heat flux w r radial coordinate m r dimensionless radial coordinate m symbol description unit ra * modified rayleigh number rr radius ratio s fin pitch m t temperature k t fin thickness m ur,uϕ,uz velocity component in r,ϕ and z direction m/s ur, uϕ, uz dimensionless velocity component in r, ϕ and z direction x, y, z cartesian coordinate system m z dimensionless axial coordinate iraqi journal of chemical and petroleum engineering vol.18 no.2 (june 2017) 109 123 issn: 1997-4884 improving of design parameters of an industrial continuous catalytic reforming reactors shymaa ali hameed chemical engineering department, college of engineering, tikrit university email: sh.a.hamed@tu.edu.iq abstract catalytic reforming of naphtha occupies an important issue in refineries for obtaining high octane gasoline and aromatic compounds, which are the basic materials of petrochemical industries. in this study, a novel of design parameters for industrial continuous catalytic reforming reactors of naphtha is proposed to increase the aromatics and hydrogen productions. improving a rigorous mathematical model for industrial catalytic reactors of naphtha is studied here based on industrial data applying a new kinetic and deactivation model. the optimal design variables are obtained utilizing the optimization process in order to build the model with high accuracy and such design parameters are then applied to get the best configuration of this process by new design variables. new results related to aromatic and hydrogen production have been obtained (the highest hydrogen and aromatic) in comparison with those reported in the literature and with the conventional method. key words: naphtha reforming, continuous catalytic reactors, kinetic model, regeneration. introduction in order to achieve environmental regulations, octane number of the produced gasoline should be increment to an acceptable level. continuous catalytic reforming (ccr) operation is regarded as a proper choice to fulfill this goal. continuous catalytic reforming (ccr) of naphtha is a significant operation to produce high octane gasoline called reformate, aromatic feedstock and hydrogen in petrochemical industries [1-3]. for designing new plants and optimizing the existing ones, a suitable mathematical model to simulate the industrial ccr reactor is required. the naphtha feedstock is a very complex containing many components and each of them undergoes different reactions. a detailed model with taking into accounts all the components and reactions in addition to the catalyst deactivation is a hard task and thus an appropriate lumping of the components by carbon number based on similar properties and kinetic behavior should be more convenient [4-6]. therefore, efforts have made for modelling ccr reactors of naphtha by considering kinetic lumps (groups of components) in reforming reactions. such progress is observed in illustrating better kinetic university of baghdad college of engineering iraqi journal of chemical and petroleum engineering mailto:a.t.jarullah@tu.edu.iq improving of design parameters of an industrial continuous catalytic reforming reactors 110 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net and deactivation mechanisms with higher predictive ability and presenting more efficient reactor setups to improve the production yield and operating conditions [7-10]. the aim of the present study is to improve the design parameters for naphtha continuous catalytic reforming (ccr) reactors based on the industrial data obtained by a real plant to achieve the optimal design and operations of such process. the model introduced is firstly investigated by employing the optimization process to obtain the optimum decision variables with a big challenge, which is getting a high agreement between industrial data and the model results (with average absolute error less than 1% among all results). secondly, the model is then used to maximize the production rate (higher hydrogen and aromatic production than those reported in the literature and obtained in the industrial plant). modeling, simulation and optimal design via optimization of the industrial ccr reactor are carried out by gproms (general process modeling system) package. process description of ccr reactor an industrial scheme of a continuous catalytic reforming process is shown in figure 1. the industrial process consists of a series of four separate reactors (the first one is the smallest and the last reactor is the largest) and a regeneration system. regenerated catalysts is entered the top of the 1 st reactor and is moved axially through the reactor then exit from the bottom of the reactor. the catalyst is moved from the bottom of the 1 st reactor to the top of the next reactor and such behavior is repeated up to the last reactor. the catalyst will be withdrawn from the last reactor and is sent to the regenerator. after that, the regenerated catalyst is sent to the 1 st reactor again, where gas-lift method is employed for catalyst circulation between the reactors and the regenerator. r e a c to r 1 r e a c to r 2 r e a c to r 3 r e a c to r 4 r e g e n e r a to r s ta b il iz e r reformate off gas net hydrogen gas separator compressor hydrogen recycle gas naphtha heat exchanger n a p h th a s tr e a m heater c a ta ly s t s tr e a m regenerated catalyst fig. 1: industrial scheme of a continuous catalytic reforming process http://www.iasj.net/ shymaa ali hameed -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 111 the feedstock is passed through all reactors and the liquid product obtained by the last reactor will be sent to the separator (where hydrogen rich gas is separated from hydrocarbons). then, products are passed to the stabilizer and the exit reformate obtained via the bottom of the stabilizer will be sent to storage for gasoline blending. table 1 shows the characterization of the industrial ccr process (feedstock, catalyst, reactors) taken from a real industrial ccr plant reported in the literature [11]. table 1: characterization of the industrial ccr process property values feedstock feed (naphtha) 233637.01 (kg/hr) hydrogen to hydrocarbon (mole ratio) 2.193 h2 in recycle (mole %) 0.83 catalyst particle diameter 1.8 (mm) specific surface area 220 (m 2 /g) void fraction 0.36 bulk density 680 (kg/m 3 ) platinum (pt) 0.3 (wt %) tin (sn) 0.3 (wt %) industrial reactors first reactor second reactor third reactor fourth reactor catalyst distribution (wt %) 12 18 25 45 reactor length to reactor diameter (l/d) 3.88 4.40 4.78 5.33 outlet temperature (◦c) 434 452 470 488 outlet pressure (kpa) 581 535 490 446 hydrogen production (kg/h) 14030 16435 18560 20340 aromatic production (kg/h) 69230 107785 142660 174600 naphthene production (kg/h) 23000 12036 7172 3960 paraffine production (kg/h) 164085 128780 89790 52220 mathematical modeling in this study, hard efforts have been made to improve the design parameters to obtain an accurate mathematical model of the industrial continuous catalytic reforming reactors of naphtha based on the industrial data reported in the literature [12, 13]. in order to develop the industrial reactor model for ccr process with high accuracy, mass and energy balances are required in addition to the catalyst deactivation, pressure drop, thermodynamic and kinetic relations. the overall continuous catalytic reforming reactors model introduced in this work are assembling the mass and energy balance on the system of reforming reactions, kinetic models for reforming reaction and catalyst deactivation model that has not been taken widely into considerations for such reactors as well as ergun's equation to calculate the pressure drop in the differential format. the following assumptions are made during the modelling of such reactors: the reactors are operated in steady-state conditions, heat loss is negligible, a homogeneous catalyst moving bed is considered and the gas mixtures are considered to be ideal. mass balance the mass flow rate of each component through the ccr reactor containing catalyst is calculated by the following equation: ∑ ,i= 1,2,3 …., 26 …(1) http://www.iasj.net/ improving of design parameters of an industrial continuous catalytic reforming reactors 112 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net where, nr is the number of reactions, fi is the molar flow rate of the component i (kmol/h), s the rate of reaction j ( ), w is the catalyst weight (kg), is the stochiometry coefficients of species i in reaction j. energy balance the energy balance equation for the ccr reactor containing catalyst is evaluated by the following correlation: ∑ ∑ …(2) where, t is the temperature (k), cpi is the heat capacity of component i (kj/kmol.k), δhj is the heat of reaction of reaction j (kj/kmol). pressure drop the pressure drop through the reactors can be calculated by using the ergun's equation as presented in the following equation [3]: …(3) where, p is the total reactor pressure (bar), ρ is the density of the gas mixture (kg/m 3 ), ac is the cross sectional area of the bed (m 2 ), μ is the viscosity of the gas mixture (cp), dp is the diameter of the catalyst particle (m), ρc is the density of the catalyst (kg/m 3 ), is the void fraction of catalyst bed (-), g is the superficial mass velocity of gas mixture (kg/m 2 .s). chemical reaction network the naphtha feedstock and reforming products are included as 26 hydrocarbon lumps characterized by naphthenes (alkylcyclohexanes (ach) and alkylcyclopentanes (acp)), normal paraffins (np), isoparaffins (ip), and aromatic (a) lumps with carbon numbers ranging from c6 to c9 + with 47 reforming reactions. the impact of pressure drop is also considered [4, 8]. in this model, the lumps of hydrocarbons related to the main reforming reactions network can be described as follows [1,5,11,14]:  dehydrogenation reactions the formation of aromatics by dehydrogenation of cyclohexanes is an endothermic reaction leading to an increase in the octane number. such reaction is the fastest among all the reforming reactions, therefore equilibrium state is quickly occurred. the reaction rate equations for this reaction are stated as: ( ) …(4) ( ) …(5) ( ) …(6)  dehydrocyclization reactions in the reforming process, dehydrocyclization of paraffins to naphthenes and aromatics is a desirable reaction due to induce the most considerable increment in octane number among the naphtha reforming reactions. the most reactions of dehydrocyclization are endothermic and promoted by high temperature, low pressure and by both metallic and acidic functions of the catalyst. the needed reactions with the reaction rate equations are written as follows: ( ) …(7) http://www.iasj.net/ shymaa ali hameed -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 113 ( ) …(8) ( ) …(9) ( ) …(10) ( ) …(11) ( ) …(12) ( ) …(13) ( ) …(14) ( ) …(15) ( ) …(16) ( ) …(17) ( ) …(18)  isomerization reactions isomerization reactions are regarded as important reactions owing to the branched hydrocarbons that have a high octane number compared with others and such reactions are promoted via acid catalyst function. in the reforming process, the isomerization reactions are endothermic reaction and paraffins and naphthenes compounds are isomerized. the following equations are used to describe the isomerization reactions: ( ) …(19) ( ) …(20) ( ) …(21) ( ) …(22) ( ) …(23) ( ) …(24)  paraffins and naphthenes cracking reactions in this process, carbons bonds are breaking in the reformer reactors at any positions along the hydrocarbon chain. the aim of these reactions is to reduce the low octane number paraffins and naphthenes from reformate leading to produce lighter hydrocarbons having higher octane in the products. such reactions are catalyzed via acidic or metallic function of the catalyst. reaction with the rate equations for hydrocracking of paraffins are shown below as follows: ∑ ( ) …(25) ( ) …(26) http://www.iasj.net/ improving of design parameters of an industrial continuous catalytic reforming reactors 114 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net ∑ ( ) …(27) ( ) ...(28) ∑ ( ) …(29) ( ) …(30) ∑ ( ) …(31) ( ) …(32)  hydrodealkylation reactions in these reactions, the branched radical of aromatic ring is cleavage in the presence of hydrogen. this reaction is considered the slowest of the reforming reactions, which is catalyzed by the metallic function of the catalyst and is favored at high temperature and pressure reactions. the needed chemical reactions with the rate equation for hydrodealkylation process are given as follows: ( ) …(33) ( ) …(34) catalyst deactivation coke deposition on the catalyst is an undesirable by-product in the ccr process and coke formation is a significant issue for catalyst deactivation. catalyst deactivation is primarily a function of coke deposition on the catalyst leading to block the active sites and reducing the yield of product therefore controlling coke deposition is equivalent to control the catalyst deactivation [15]. this deactivation effect is compensated by increasing the operating temperature so that the yields of primary products are kept constant. however, there is a limit for increasing the temperature after a certain value that can not yield reformate of desired quality. then the catalyst has to be regenerated for using in the next cycle of operation [4]. the perfect model should accurately be predicted the rates of coke formation and the catalyst deactivation on the reactor performance as a function of operating conditions [1618]. therefore, the following equations related to the catalyst deactivation have taken into accounts in this work as presented below, where the rate of reaction over a spent catalyst can be evaluated via multiplying the activity of the catalyst and the rate of reaction over fresh catalyst: …(35) …(36) where, is the rate of i th reaction of fresh catalyst (coke content is zero), is the rate of i th reaction of spent catalyst, is the catalyst activity (which is a function of deposited coke), is the deactivation constant, is the coke weight fraction. the related reaction rate constants, equilibrium constants, activation energies, frequency factors, heat of reactions, heat capacities, etc.) can be found elsewhere [1, 4, 12, 19]. http://www.iasj.net/ shymaa ali hameed -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 115 case studies case 1: the minimization of the sum of the squared production (ssp) between the industrial data and estimated yields of hydrogen, aromatics, naphthene and paraffine components at the end of each reactor under the same characterization of the industrial ccr reactors (operating conditions, catalyst distribution and properties, feedstock, reactors) is used as an objective function in the optimization process to evaluate the optimal decision variables. non-linear regression is employed to optimize the control variables (inlet reaction temperature and pressure for each reactor simultaneously) including the outlet temperature, the outlet pressure, hydrogen production, aromatic production, naphthene production and paraffine production of the industrial unit as process constraints and the average absolute error must not exceed 1% among all results. the following equation is employed for this purpose: ∑ …(37) case 2: the optimization process in case 2 is aimed to maximize the productivity of hydrogen and aromatics, where the optimal outlet temperature and pressure, catalyst distribution and hydrogen to hydrocarbon ratio for each reactor is obtained. the optimal design parameters obtained in case 1. are utilized in case 2 as constraints. the following objective function for case 2 can be introduced as follows: ...(38) optimization problem formulation mathematically, the optimization problem for case 1 can be described as: min ssp tin,i, pin,i , i=1,..no. of reactors subject to y(w, m(w), u(w), g(w), q)= 0, tin,i l ≤ tin,i ≤ tin,i u pin,i l ≤ pin,i ≤ pin,i u tout,i l ≤ tout,i ≤ tout,i u pout,i l ≤ pout,i ≤ pout,i u prh2 l ≤ prh2≤ prh2 u praromatic l ≤ praromatic≤ praromatic u prnaphthene l ≤ prnaphthene ≤ prnaphthene u prparaffine l ≤ prparaffine≤ prparaffine u while, the optimization problem for case 2 is stated as: max pr tout,i , pout,i , catdis , i=1,..no. of reactors tout,i l ≤ tout,i ≤ tout,i u pout,i l ≤ pout,i ≤ pout,i u catdis l ≤ catdis ≤ catdis u h2/hc h2/hc * catact l ≤ catact≤ catact u [pr1(in) – pr4(out)] [pr1(in) – pr4(out)] * prh2 prh2 * praromatic praromatic * y(w, m(w), u(w), g(w), q)= 0 represents the system model described above, where w is the independent variable (catalyst distribution), m(w) denotes the set of all differential and algebraic variables, u(w) represents the derivative of differential variables with respect to catalyst distribution, q gives the design variables, and g(w) is the control variables. pri is the productivity of component i, catdis is the catalyst distribution, catact is the catalyst activity, pr is the reactor pressure, l and u is the lower and upper bound, respectively. results and discussion optimal design parameters for case 1 the effect of optimized parameters of the industrial ccr reactor has been investigated here. the optimal design parameters for the industrial continuous catalytic reforming (ccr) reactors are reported in table 2 based on the industrial data obtained by a real http://www.iasj.net/ improving of design parameters of an industrial continuous catalytic reforming reactors 116 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net plant for getting the optimal design and operations of such process. table 2: optimization problem results for case study 1 decision variables optimal values 1 st reactor 2 nd reactor 3 rd reactor 4 th reactor inlet temperature (◦c) tin1=518.03 tin2=516.31 tin3=515.07 tin4=514.11 inlet pressure (kpa) pin1=595.02 pin2=550.21 pin3=505.34 pin4=460.15 outlet temperature (◦c) tout1=434.01 tout2=451.98 tout3=470.11 tout4=488.09 outlet pressure (kpa) pout1=580.8 pout2=535.6 pout3=490.4 pout4=445.7 hydrogen production (kg/h) 14033.202 16430.400 18591.453 20342.362 aromatic production (kg/h) 69234.866 107786.297 142668.738 174600.000 naphthene production (kg/h) 23000.279 12036.027 7172.520 3961.580 paraffine production (kg/h) 164087.056 128780.230 89788.789 52219.1360 catalyst activity (%) 0.950 0.943 0.938 0.918 absolute error of the industrial product compositions and present study hydrogen production (%) 0.023 0.028 0.169 0.012 aromatic production (%) 0.007 0.001 0.006 0.000 naphthene production (%) 0.001 0.008 0.007 0.039 paraffine production (%) 0.001 0.000 0.001 0.002 as can be seen from these results, a very good agreement is obtained by using the optimization process. where, the optimum decision variables with the target values among all results between the industrial data and model results have been achieved with average absolute error less than 1% under process conditions and constraints. the best inlet reaction temperature that should be applied for getting the actual temperature of the industrial naphtha ccr reactors are optimized to be 518.03 c, 516.31 c, 515.07 c and 514.11 c for reactor 1, 2, 3 and 4, respectively. whereas, the best inlet reaction pressure that should be utilized for getting the actual pressure for the industrial naphtha ccr reactors are optimized to be 595.02 kpa, 550.21 kpa, 505.34 kpa, and 460.15 kpa, for reactor 1, 2, 3 and 4, respectively. the optimal decision variables presented above have been obtained under process limitations for each reactor (outlet temperature, outlet pressure, hydrogen production, aromatic production, naphthene production and paraffine production). such new results can be attributed to the accuracy of the model studied here under process conditions and constraints, where all the necessary design parameters, reaction rate equations as a function of operating conditions (obtained based on the experimental data, mass and energy balance, hydrodynamic parameters, physiochemical properties in addition to the catalyst activity that ignored in the literature) have taken into considerations here. such design and kinetic parameters can effect on the process leading to reduce the sensitivity analysis of the process and giving high deviation and as a results the performance and the behaviour of the process can not be predicted confidently in addition to the advanced solution method utilized here (successive quadratic programming (sqp)). based on the results presented above, a clear indication is observed that the accuracy of the mathematical model related to the design parameters can now be applied with high trusted for modifying such design parameters by changing the decision variables in order to improve quality and quantity of the process via maximizing the hydrogen and aromatic production. http://www.iasj.net/ shymaa ali hameed -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 117 optimal design parameters for case 2 after getting the optimal results of case 1, the optimization process is applied for case 2 in order to obtain the maximum productivity of hydrogen and aromatic. the optimal results related to case study 2 are given in table 3. as noted from this table, the highest hydrogen production is optimized to be 20821.857 kg/h (while 20342.362 kg/h for conventional process) and aromatic production of 191428.973 kg/h (whereas 174600.0 kg/h for conventional process). such new results have got utilizing the optimization technique of the decision variables simultaneously (not individually for each variable as presented in the literature). where, the best outlet temperature and pressure is 444 c and 476.4 kpa, 462 c and 544.2 kpa, 482 c and 496.6 kpa, and 497 c and 451.3 kpa for reactor 1, 2, 3 and 4, respectively. also, the new catalyst distribution and h2/hc should be ordered simultaneously beside temperature and pressure as follows: 21.4 wt% and 2.193, 22.2 wt% and 2.898, 26.8 wt% and 3.491, and 29.6 wt% and 4.857 for reactor 1, 2, 3 and 4, respectively, under process constraints (the catalyst activity, pressure difference and the productivity of hydrogen and aromatic). table 4 shows the comparison results obtained from this study and those obtained by previous studies related to the production increasing of hydrogen and aromatic. it is clearly observed from this table that the production increasing of hydrogen (by 481.857 kg/h) and aromatic (16828.973) is higher than conventional method and those obtained in the literature, which becomes a considerable amount per year. this new results is attributed to the improvement of design parameters investigated here (outlet temperature, outlet pressure, catalyst distribution and process constraints) in addition to the solution method (sqp) employed in this study depending on the modified model. where, this method used here to maximize the production of hydrogen and aromatic is better than the methods used with all previous works (that used different solution methods for maximizing the objective function to get the optimal design of ccr reactor) in this field. such approach utilized having high accuracy in evaluating the control variables of the process within gproms package (advanced languages and formalisms for model improvement, which allow the description of difficult differential and algebraic models and has several features that make it an attractive tool and suitable for the modelling, simulation and optimization of any plant process). furthermore, this approach is a highly trusted method for solution of such mathematical models, which means that this model can be applied confidently to reactor design, operation and control leading to get higher profit (higher quality and quantity). table 3: optimization problem results for case study 2 decision variables optimal values 1 st reactor 2 nd reactor 3 rd reactor 4 th reactor outlet temperature (◦c) tout1=444.0 tout2=462.0 tout3=482.0 tout4=497.0 outlet pressure (kpa) pout1=576.40 pout2=544.2 pout3=496.6 pout4=451.3 catalyst distribution (wt %) 21.4 22.2 26.8 29.6 h2/hc 2.193 2.898 3.491 4.857 catalyst activity (%) 0.943 0.937 0.927 0.912 pr1(in) – pr4 (out) (kpa) 147.8 hydrogen production (kg/h) 14673.069 17606.492 19768.371 20821.857 aromatic production (kg/h) 86759.027 136484.659 173364.538 191428.973 http://www.iasj.net/ improving of design parameters of an industrial continuous catalytic reforming reactors 118 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net table 4: comparison results between this work and previous studies authors (year) production increasing of hydrogen (kg/h) production increasing of aromatic (kg/h) rahimpour et al. (2011) 54.432 414.600 iranshahi et al. (2013) 322.560 6633.600 karimi et al. (2014) 383.040 9535.800 this study (2016) 481.857 16828.973 the performance of the industrial ccr reactor the effect of optimized parameters on industrial ccr performance has been investigated and compared with the performance of the non-optimized operations in the figures 2-8. the reaction side temperature profiles of industrial (conventional) and recuperative reactors are illustrated in figure 2. owing to the predominant reactions in the naphtha reforming process are highly endothermic, temperature drop along the reaction side is expected and the temperature drops using the optimized parameters (case 2) are lower than the industrial method (case 1). fig. 2: temperature profiles along four ccr reactors for case studies this reduction in temperature drop can be attributed to heat transfer from exothermic side. in the first reactors, concentration of naphthenes is high and dehydrogenation, which is very rapid and endothermic reaction, takes place. hence, very sharp temperature drop occurs in this reactor. while in the last reactors, naphthenes concentration decrease and hydrocracking and hydrodealkylations occur, which are very slow and exothermic reactions, thus, temperature drop is lower. as well as, the hydrogen content of the recycled gas decreases in the optimized configurations and the molar flow rate of the recycled gas will be increased by increasing in h2/hc molar ratio. using the optimized design parameters, more recycled gas enters the reactors, which acts as a thermal source and leading to less temperature drop. due to the relationship between the temperature gradient and the molar flow rate, the sum of the fresh naphtha feed and recycled gas, the temperature drop along the optimized reactors is the least due to an increase in the molar flow rate [1, 12]. one of the advantages of the ccr reactor is to reduce the pressure drops in the reactors allowing to use of smaller catalyst particle with high efficiency and the reaction rate and conversion increase with decreasing the pressure drop. so, other significant design parameter that influences the performance of naphtha reforming process is operating pressure. figure 3 shows the pressure profile for industrial and both case studies. as can be observed from this fig., the pressure drop in the industrial reactors is higher than the optimized reactors (case 2) due to the design parameters of such reactor in which the catalyst distribution reactors is longer than that of conventional process. the sudden pressure drops during the passage of stream through the reactors are due to http://www.iasj.net/ shymaa ali hameed -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 119 piping and employing intermediate instruments such as furnaces [11]. catalyst weight (%) 0 10 20 30 40 50 60 70 80 90 100 p r e s s u r e ( k p a ) 420 440 460 480 500 520 540 560 580 600 620 industrial case 1 case 2 fig. 3: pressure profiles along four ccr reactors for case studies the hydrogen and aromatic yield vs. the catalyst distribution for both case studies is illustrated in figure 4 and 5, respectively. one of the positive impacts of the proposed modifications can clearly be observed in these figures. hydrogen is regarded the most the source of hydrocracking, hydrotreating and hydroprocessing units in the refineries. hydrogen is a product in the dehydrogenation and dehydrocyclization reactions in addition to the reactant in the hydrocracking and hydrodealkylation reactions. fig. 4: hydrogen production along four ccr reactors for case studies catalyst weight (%) 0 10 20 30 40 50 60 70 80 90 100 a r o m a t ic p r o d u c t io n ( k g /h ) 20000 40000 60000 80000 100000 120000 140000 160000 180000 200000 industrial case 1 case 2 fig. 5: aromatic production along four ccr reactors for case studies in the first two reactors, the high production rate is observed, because dehydrogenation and dehydrocyclization are dominant reactions, while in the last two reactors, production rate decreases owing to presence of hydrogen consumer reactions. as noticed, in the optimized configuration owing to supply the copious heat for dehydrogenation and dehydrocyclization reactions, hydrogen production rate has increased, which is one of the main goals in the modified configuration. aromatic production with high octane number is the main aim of reforming process hence, the aromatic yield should be increased in the proposed configuration. almost all reactions proceed more rapidly at higher temperatures hence, the aromatics and hydrogen yields increase in both optimized reactors due to a lower temperature drop compared with conventional method. moreover, the pressure drop in the reactors is considerably less than that in the conventional, so that the product yield increases as a result of increasing in reaction rates. these factors lead to higher aromatic production in the modified process configuration (case 2) compared with the traditional process (case 1). the amount of http://www.iasj.net/ improving of design parameters of an industrial continuous catalytic reforming reactors 120 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net aromatic flow rate has increased as the stream passes through the reactors owing to aromatic producing reactions such as dehydrogenation and dehydrocyclization of paraffins to aromatics. as well as, higher aromatic production is achieved employing case 2 configuration and consequently, high octane gasoline can also be produced in this configuration. where, the rate of aromatics production is higher than those produced by the conventional method due to the dehydrogenation of naphthenes to aromatics [1]. the naphthenes and paraffins production rates are illustrated in figure 6 and 7, respectively for both case studies. naphthenes and paraffins constitute the main part of naphtha. since dehydrogenation of naphthene is the major source of aromatic production and octane number enhancement, naphthenes play a very important role in naphtha reforming process. since naphthenes are consumed in the naphtha reforming process and their flow rates decline along the catalyst distribution of the reactors. owing to hydrogenation reaction in naphtha reforming reactors, more heat is available for the dehydrogenation of naphthens, which is endothermic and its yield increases by consuming more heat. catalyst weight (%) 0 10 20 30 40 50 60 70 80 90 100 n a p h th e n e p r o d u c ti o n ( k g /h ) 0 5000 10000 15000 20000 25000 30000 35000 40000 45000 50000 industrial case 1 case 2 fig. 6: naphthene production along four ccr reactors for case studies catalyst weight (%) 0 10 20 30 40 50 60 70 80 90 100 p a r a ff in e p r o d u c t io n ( k g /h ) 20000 40000 60000 80000 100000 120000 140000 160000 180000 200000 industrial case 1 case 2 fig. 7: paraffin production along four ccr reactors for case studies also, hydrocracking as another naphthene consumer reaction is favored at high temperature thus, the highest conversion of naphthene is observed in optimized design parameters (modified configuration – case 2) that operate at higher temperature. as well as, the paraffins production declines continuously along the catalyst distribution inside the reactors owing to dehydrocyclization and hydrocracking reactions. using the optimized parameters, more heat is accessible leading the dehydrocyclization toward consuming more paraffins. on the other hand, hydrocracking is favored at high temperature and it can progress further in the modified configuration having a higher operating temperature. therefore, a lower position in comparison with the conventional configuration [11, 12] is observed. the catalyst activity along the catalyst distribution for both case studies is shown in figure 8. the catalyst activity has a reverse relationship with temperature and the catalyst activity is increased as proceeding along the reactors due to a decrease in temperature. as clearly observed, the catalyst activity deteriorates considerably owing to coke deposition on the catalyst surfaces and sintering http://www.iasj.net/ shymaa ali hameed -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 121 phenomena. it is worth mentioning that the catalyst activity itself does not convey any independent judgment, and its effect on the production rate should be investigated. one of the main goals is to keep the catalyst activity as high as possible under process conditions with taking into considerations the optimal design parameters that should be modified. catalyst weight (%) 0 10 20 30 40 50 60 70 80 90 100 c a t a ly s t a c t iv it y 0.89 0.90 0.91 0.92 0.93 0.94 0.95 0.96 case 1 case 2 fig. 8: catalyst activity along four ccr reactors for case 1 and case 2 conclusions a new configuration of industrial continuous catalytic reforming reactors of naphtha is studied by improving the design parameters of such process in order to boost the aromatics and hydrogen productions as a result of increasing the efficiency of the reformers. a rigorous mathematical model for ccr reactors of naphtha is investigated here depending on industrial data with taking into account the deactivation model. the optimal design variables have obtained employing the optimization process in order to build the model with high accuracy (with average absolute error less that 1% among all results between the industrial data and model results). then, such design parameters have been employed for getting the best configuration of the process by improving the design parameters. the results of the modified design parameters showed about 16828.973 and 481.857 kg/h have increase in the aromatics and hydrogen production, respectively, compared with those reported in the literature and obtained with the conventional method. such new results have clearly indicated that the modified design parameters of ccr reactors can cause excellent configuration in comparison with the conventional system. nomenclature a constant a constant b constant ccr continuous catalytic reactor n number of carbon atom pt total pressure (kpa) pan partial pressure of n carbon aromatic (kpa) pachn partial pressure of n carbon alkylcyclohexane (kpa) pacpn partial pressure of n carbon alkyl-cyclopentane (kpa) ph2 partial pressure of hydrogen (kpa) pipn partial pressure of n carbon isoparaffin (kpa) pnpn partial pressure of n carbon normal-paraffin (kpa) sqp successive quadratic programming ssp sum of the squared production .3 r gas constant (j mol -1 k -1 ) t temperature (k) * the target final value in inlet out outlet references 1iranshahi, d.; rafiei, r.; jafari, m.; amiri, sh.; karimi, m.; rahimpour, m.r., (2013), “applying new kinetic and deactivation models in simulation of a novel thermally coupled reactor in continuous catalytic regenerative naphtha http://www.iasj.net/ improving of design parameters of an industrial continuous catalytic reforming reactors 122 ijcpe vol.18 no.2 (june 2017) -available online at: www.iasj.net process”, chemical engineering journal, vol. 229, pp. 153. 2maria, s.; kravtsov, a.v.; ivanchina, e.d.; korolenko, mv.; chekantsev, nv., (2011), “reactor modeling and simulation of moving-bed catalytic reforming process”, chemical engineering journal, vol. 176–177, pp. 134. 3taskar, u.m., (1996), “modeling and optimization of a catalytic naphtha reformer”, phd thesis, texas university. 4padmavathi, g.; chaudhuri, k.k., (1997), “modeling and simulation of commercial catalytic naphtha reformers”, canadian journal of chemical engineering, vol. 75, pp. 930. 5behin, j.; kavianpour h.r., (2009), “a comparative study for the simulation of industrial naphtha reforming reactors with considering pressure drop on catalyst”, petroleum and coal, vol. 51, pp. 208. 6askari a.; karimi, h.; rahimi, m.r.; ghanbari, m., (2012), “simulation and modeling of catalytic reforming process”, and coal, vol. 54, pp. 76. 7weifen, h.; hongye, s.; yongyou, h.; jian, c., (2006), “modeling, simulation and optimization of a whole industrial catalytic naphtha reforming process on aspen plus platform”, chinese journal of chemical engineering, vol. 14, pp. 584. 8hongjun, z.; mingliang, s.; huixin, w.; zeji, l.; hongbo j., (2010), “modeling and simulation of moving bed reactor for catalytic naphtha reforming”, petroleum science and technology, vol. 28, pp. 667. 9taghavi, b.; fatemi, s., (2014), “modeling and application of response surface methodology in optimization of a commercial continuous catalytic reforming process”, chemical engineering communication, vol. 201, pp. 171. 10rodríguez, m.a.; ancheyta, j., (2011), “detailed description of kinetic and reactor modeling for naphtha catalytic reforming”, fuel, vol. 90, pp. 3492. 11iranshahi, d.; karimi, m.; amiri, sh.; jafari, m.; rafiei, r.; rahimpour, m.r., (2014), “modeling of naphtha reforming unit applying detailed description of kinetic in continuous catalytic regeneration process”, chemical engineering research and design, vol. 92, pp. 1704. 12iranshahi, d.; amiri, sh.; karimi, m.; rahimpour, m.r.; rafiei, r.; jafari, m.; rahimpour, m.r., (2013), “modeling and simulation of a novel membrane reactor in a continuous catalytic regenerative naphtha reformer accompanied with a detailed description of kinetics”, energy and fuels, vol. 27, pp. 4048. 13iranshahi, d.; karimi, m.; amiri, sh.; jafari, m.; rafiei, r.; rahimpour, m.r., (2013), “modeling and simulation of a novel membrane reactor in a continuous catalytic regenerative naphtha reformer accompanied with a detailed description of kinetics”, energy and fuels, vol. 27, pp. 4048. 14saidi, m.; mostoufi, n.; sotudehgharebagh, r., (2011), “modeling and simulation of continuous catalytic regeneration (ccr) process”, international journal of applied engineering dindigul, vol. 2, pp. 115. 15antos, g.a.; aitani, a.m., (1995), “catalytic naphtha reforming”, 2 nd ed., new york, marcel dekker. 16ren, x.h.; bertmer, m.; stapf, s.; demco, d.e.; blümich, b.; http://www.iasj.net/ http://www.sciencedirect.com/science/journal/0926860x shymaa ali hameed -available online at: www.iasj.net ijcpe vol.18 no.2 (june 2017) 123 kern, c.; jess, a., (2002), “deactivation and regeneration of a naphtha reforming catalyst”, applied catalysis a: general, vol. 228, pp. 39. 17de pauw, r.p.; froment, g.f., (1975), “deactivation of a platinum reforming catalyst in a tubular reactor”, chemical engineering science, vol. 30, pp.789. 18van trimpont, p.a.; marin, g.b.; froment, g.f., (1988), “reforming of c7 hydrocarbons on a sulfided commercial pt/al2o3 catalyst”, industrial and engineering chemistry research, vol. 27 pp.51. 19reid, r.c.; prausnitz, j.m.; poling, b.e., (1987), “the properties of gases and liquids”, 4 th ed., new york, mcgraw-hill. http://www.iasj.net/ http://www.sciencedirect.com/science/journal/0926860x iraqi journal of chemical and petroleum engineering vol.16 no.1 (march 2015) 1320 issn: 1997-4884 electrochemical removal of copper from synthetic wastewater using rotating cylinder electrode qasim j. m. slaiman, *cecilia k. haweel and suha a. mohammed *chemical engineering department, university of bagdad abstract the performance of a batch undivided electrochemical reactor with a rotating cylinder electrode of woven-wire (60 mesh size), stainless steel 316, is examined for the removal of copper from synthetic solution of o.5 m sodium chloride containing 125 ppm at ph ≈ 3.5. the effect of total applied current, rotation speed on the figures of merit of the reactor is analyzed. for an applied current of 300 ma at 100 rpm, the copper concentration decreased from 125 to mg l -1 after 60 min of electrolysis with a specific energy consumption of 1.75 kwh kg -1 and a normalized space velocity of 1.62 h -1 . the change in concentration was higher when the total applied currents were increased because of the turbulence-promoting action of the hydrogen evolution. the results suggest that the applied current must represent a compromise between the increase in space time yield or normalized space velocity and the increase in the specific energy consumption. key words: electrochemical effluent treatment, rotating cylinder electrode, copper removal introduction of all the natural resources, water is unarguably the most essential and precious. life began in water and life is nurtured with water. it is a universal solvent and as a solvent, it provides the ionic balance and nutrients [1], and supports all forms of life. so that any pollution in water can be a major problem spatially when the pollutants are heavy metal ions, although heavy metals are natural components of the environment but when their concentrations increase more than normal levels they become potentially hazardous [2]. at the last decades, the problem has extended due to the increasing in industries and the wars that there effect keep on many years. heavy metals are elements having atomic weights between 63.5 and 200.6, and a specific gravity greater than 5.0 [3]. copper is an essential element needed for human and other living organisms, which primarily involves several proteins and enzymes. copper is used to make electrical wiring, pipes, valves, fittings, coins, cooking utensils and building materials. it is present in munitions, alloys (brass, bronze) and coatings. copper compounds are used also in fungicides, algicides, insecticides and wood preservatives and in iraqi journal of chemical and petroleum engineering university of baghdad college of engineering electrochemical removal of copper from synthetic wastewater using rotating cylinder electrode 14 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net electroplating, azo dye manufacture, engraving, lithography, petroleum refining and pyrotechnics. copper compounds, can be added to fertilizers and animal feeds as a nutrient to support plant and animal growth. deficiency of copper causes demineralization of bones, anemia, fragility of arteries, and discoloration of skin as well as hair. high concentration of copper (above 3.0 mg/l) in water may lead to accumulation of copper in liver and lenticular nucleus of brain. ultimately, it may cause hepatic cirrhosis and brain necrosis. renal damage may also occur due to accumulation of copper in kidney by means of consumption of water with high copper concentration in excess of permissible limit [4]. wastewaters from metal finishing, textile industries, electronics industry or washing effluents for remediation of soil contaminated with copper may contain up to 500 mg/l copper, which, depending on the worldwide environmental regulations and must be controlled to a permitted level before being discharged into the environment [5]. where, the permissible limit of copper in sources of drinking water just like rivers is between 1.5 to 2 mg/l according to the eu [6]. the electricity has been used to treat water firstly in uk in 1889 [7]. electrochemical methods involve the plating-out of metal ions on a cathode surface and can recover metals in the elemental metal state. electrochemical wastewater technologies involve relatively large capital utilization. however, with the stringent environmental regulations regarding the wastewater discharge, electrochemical technologies have regained their importance worldwide during the past two decades [8]. the applications of electrochemical technology in environmental treatment are a clean technology and the only processes have the ability to recycle materials. because of the rate of the electrodeposition was limited by masstransport problems hydrodynamic electrodes are developed. hydrodynamic electrodes are electrodes, which function in a regime of forced convection. the advantage of these electrodes is increased transport of electroactive species to the electrode, leading to higher currents and thence a greater sensitivity and reproducibility. most of the applications of these electrodes are in steady-state conditions, i.e., constant forced convection and constant applied potential or current [9]. electrodes have been rotated at least since 1905 to provide some quantitative control of solution conviction [10]. recently, some authors have focused attention on the electrolytic treatment of copper; reade et al. [11] studied the removal of cadmium and copper with a reticulated vitreous carbon rotating cylinder electrode. a decrease in cadmium concentration from 56 ppm to less than 1 ppm was reported. in a previous paper from this laboratory [12] it was reported that a packed bed rotating cylinder electrode of woven wire meshes presents mass transport coefficients three times higher than those obtained with smooth electrodes because of the turbulence-promoting action of the meshes. the present study focused on the analysis of the behavior of an undivided electrochemical reactor with a rotating packed bed electrode of woven wire meshes for the removal of copper and the study of the process variables, such as rotation speed, total applied currents on the ‘figures of merit’ of the reactor. qasim j. m. slaiman, cecilia k. haweel and suha a. mohammed -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 15 experimental work the experiments were performed in an undivided batch reactor, is consisted of three electrodes and placed in 2l beaker at which the electrolyte 900 ml volume has been treated. cathode electrode was used in dimensions as 3.5, 3 cm diameter and long respectively. the lower part of the electrode was open but the upper part was joined to a teflon sleeve in order to orientate the electrolyte flow through the mesh. a perforated teflon disc was used on the top of the working electrode sleeve, centrally positioned, where teflon shaft was passed through it, which is used as supporting for the electrochemical cell and to distribute the electrical connections to the electrodes. four planer graphite anodes (10×0.7×5 cm), fixed in teflon disc at the bottom of the anode plates and they were fixed from the top with the perforated teflon disc, which is proved a good support. the gap between the cathode and anode plates was 1.5 cm and calomel reference. figure 1 depicts schematically the complete experimental arrangement. fig. 1, general view of the reactor,(1) beaker 2l,(2) electrical mixer,(3) reference electrode,(4) counter electrode,(5) anode electrode,(6) digital voltmeter,(7) electrical connecter,(8) digital ammeter,(9) resistance box,(10) power supply. all solutions were prepared using analar grade chemicals and distilled water. cupric ion solutions were prepared by dissolving copper chloride in an aqueous solution of 0.50 nacl at ph 3.5. the concentration of copper ions was monitored by atomic absorption analysis using an air–acetylene flame, in order to determine the variation of concentration with time and the differential concentration decrease. from these data the current efficiency, the space time yield, the normalized space velocity and the specific energy consumption were intended. the anodic reaction was oxygen evolution: ...(1) the main cathodic reaction is: ...(2) and the side reactions were the hydrogen evolution: ...(3) theory for a rotating cylinder electrode the electrolyte is assumed to be wellmixed at all times. thus, for a batch reactor in the potential range where the tin deposition is mass-transfer controlled, the change of concentration with time is given by [13]. ( ) ( ) ( ) ….(4) consequently, the mass-transfer coefficient has to be evaluated in order to discuss the results obtained experimentally. the fractional conversion and the accumulative current efficiency as a function of time are given by, [13,14] ( ) ( ) ….(5) and ( ) ( ) ( ) ∫ ( ) …..(6) electrochemical removal of copper from synthetic wastewater using rotating cylinder electrode 16 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net other ‘figures of merit’ used to compare the performance of the electrochemical reactor are the mean value of the space time yield, the normalized space velocity and the specific energy consumption, which were calculated with the following equations: ( ) ( ) ( ) ….(7) ( ) ( ) ….(8) and ( ) ∫ ( ) ( ) ( ) ( ) ….(9) results and discussion figure 2-a shows the copper concentration as a function of time at different applied current. for a given applied current, there is a pronounced decrease in concentration during the first stages of the experiments, but at longer times, the concentration approaches a constant value. a linear decay of copper concentration is observed clearly but at total applied current -250 and -300 ma, a deviation from linearity can be seen, and while at lower applied currents the decay is linear. when the concentration ramp linearly with time this means that the deposition is under mass transfer control, which is a theoretical expectation [15, 14], within the accuracy normally expected for this type of measurements. the experimental results, in general, are in close agreement with theoretical prediction mainly during the beginning of the experiments. although the plots of normalized concentration of copper as a function of electrolysis time were apparently exponential, the expectation of linearity for the ln[c(t)/c(0)] against time plot was confirmed only for a portion of the curve, as shown in figure 2b . this behavior was also observed in previous work as for copper [16], cadmium [14, 17], tin [13], and lead [18]. where this deviation from linearity with time in the deposition of copper ions is due to the fact after halfan-hour more than 90% of copper ions had been removed then reduction in the current efficiency can be expected. fig. 3 shows the normalize and the linearization of normalized concentration of copper as a function of time at different rotation speeds. it may be observed from figure 3-a that the normalized concentrations of the copper remain practically slightly unchanged throughout the electrolysis with different rotation speeds. although in general there are reductions of concentrations with time, for longer time of deposition there is also a deviation from linearity, which can be noticed as in the decay concentration curves presented in fig. (3). fig. 2, (a.) normalized concentration of copper (c(t) /co) as a function of time. (b) linearization of normalized qasim j. m. slaiman, cecilia k. haweel and suha a. mohammed -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 17 concentration as a function of time for different applied current fig. 3, (a.) normalized concentration of copper (c(t) /co) as a function of time. (b) linearization of normalized concentration as a function of time for different rotation speeds. fig. 4, cumulative current efficiency as a function of time for different applied currents at constant rotation speed of 100 rpm fig. (4) shows typical curves of the accumulative current efficiency as a function of time at different total applied current. for a total applied current of 180 ma the current efficiency is close to 100% early in the experiment and decreases at higher times because the copper concentration decreases and the oxygen reduction predominates. for higher values of the total applied currents, hydrogen evolution possibly occurs as cathodic side reaction and lower values of current efficiencies are measured. fig. (5) and 6 show the mean value of the space time yield and the normalized space velocity as a function of the applied current where there was an increasing effect with increase in the total applied current can be noticed. fig. 5, mean value of the space time yield as a function of total applied currents at constant rotation speed of 100 rpm fig. (7) shows the specific energy consumption as a function of time for different total applied currents. for a given applied current, as the solution becomes more dilute the current efficiency decreases and the energy consumption increases. the increase in es when the total applied current increases can be attributed to a decrease in current efficiency because of the onset of hydrogen evolution. the specific energy consumption is in accordance with values previously reported [17, 19]. electrochemical removal of copper from synthetic wastewater using rotating cylinder electrode 18 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net fig. 6, normalized space velocity as a function of total applied currents at constant rotation speed of 100 rpm fig. 7, specific energy consumption as a function of time for different total applied currents at constant rotation speed of 100 rpm conclusions the following conclusions may be drawn: 1. the copper removal from dilute aqueous solution can be performed efficiently in an electrochemical reactor with a three-dimensional rotating cylinder electrode of woven wire sheet. the total applied currents show an emphatic effect on the removal rate of copper and the increasing in rotation speed also increase the removal rate of copper. 2. the copper concentration follows the expected theoretical behavior during the first stages of the experiment. 3. hydrogen evolution, as side cathodic reaction, is beneficial for tin removal because the turbulence promoting action increases the current for the main reaction and enhances the space time yield or the normalized space velocity. however, at the same time it is detrimental to the specific energy consumption because the current efficiency decreases. 4. the process shows that the removal of copper from aqueous solutions does not require addition of chemical additives, which reduces the cost and makes the process efficient and with no chemical waste or sludge. nomenclature ae reactor specific surface area (m -1 ) as electrode specific surface area (m -1 ) c concentration (mg l -1 or kg m -3 ) es specific energy consumption (w s kg 1 or kwh/kg) f faradaic constant (c mol -1 )= 96500 coulomb i total current (a) k mass-transfer coefficient (m s -1 ) m atomic weight (g mol -1 ) sn normalized space velocity (s -1 or h -1 ) t time (min or s) u cell voltage (v) v effective electrolyte volume within the reactor (m 3 ) x fractional conversion greek symbols current efficiency (%) kinematic viscosity (m 2 s -1 ) charge transfer of the electrode reaction mean space time yield (kg m -3 s -1 ) qasim j. m. slaiman, cecilia k. haweel and suha a. mohammed -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 19 references 1. iqbal m. a. and gupta s. g., studies on heavy metal ions pollution of ground water sources as an effect of municipal solid waste dumping, african journal of basic & applied science, 1 (5) :117-122 (2009). 2. jencarova j.and luptakova a., the elimination of heavy metal ions from waters by biogenic iron sulphides, chemical engineering transactions j., 28:205-210 (2012). 3. bradl h. b., heavy metals in the environment, elsevier 2005. 4. world health organization, background document for development of who guidelines for drinking water quality “copper in drinking-water” 2004 5. dermentzis, k., davidis, a., papadopoulou, d., copper removal from industrial wastewaters by means of electrostatic shielding driven electrodeionization, christoforidis, a., ouzounis, k., journal of engineering science and technology review, 2 :131 (2009). 6. imre-lucaci f., electrochemical methods for recovery of copper from waste waters and solid wastes. phd thesis, “babe¸s-bolyai” university cluj–napoca, faculty of chemistry and chemical engineering, 2011. 7. strokach p.p, mass transfer study of three-dimensional electrodes composed of stacks of nets,. electrochem. ind. process. bio. ., 55: 375 (1975). 8. wang l.k, hung y.t, and shammas n.k.,advanced physicochemical treatment technologies,. in: handbook of environmental engineering, humana press, new jersey, 5 (2007). 9. brett c. m. a. and brett a. m. o., electrochemistry, principles, methods, and applications, oxford university press, 1993. 10. gabe d. r., wilcox g. d., gonzalez-garcia j. and walsh f. c. the rotating cylinder electrode: its continued development and application ,journal of applied electrochemistry, 28: 759-780 (1998). 11. reade g. w., bond p., ponce de leon c., and walsh f.c., the application of reticulated vitreous carbon rotating cylinder electrodes to the removal of cadmium and copper ions from solution, journal of chemical technology and biotechnology , 79 (2004). 12. grau jm and bisang jm, mass transfer studies at packed bed rotating cylinder electrodes of woven-wire meshes. j appl electrochem, 36:759–763 (2006). 13. bazan j. c. and bisang j. m., electrochemical removal of tin from dilute aqueous sulfate solutions using a rotating cylinder electrode of expanded metal, journal of applied electrochemistry, 34:.501– 506 (2004). 14. grau. j. m and. bisang j. m, , electrochemical removal of cadmium from dilute aqueous solutions using a rotating cylinder electrode of wedge wire screens, journal of applied electrochemistry, 37 (2007). electrochemical removal of copper from synthetic wastewater using rotating cylinder electrode 20 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net 15. bertazzoli r., rodrigues c. a., dallan e. j., fukunaga m. t., lanza m. r. v., leme r. r., and widner r. c., braz, mass transport properties of a flow-through electrolytic reactor using a porous electrode: performance and figures of merit for pbii removal,. j. chem. eng., 15 (4) (1998). 16. alonso a. r., lapidus g. t., gonzález i, selective silver electroseparation from ammoniacal thiosulfate leaching solutions using a rotating cylinder electrode reactor (rce)., hydrometallurgy, j., 92: 115–123 (2008). 17. elsherief a.e., removal of cadmium from simulated wastewaters by electrodeposition on spiral wound steel electrode, electrochimica acta j., 48: 26672673 (2003). 18. bertazzoli, sousa m. f. b., and widner r. c., electrolytic removal of lead using a flow-through cell with a reticulated vitreous carbon cathode, journal of applied electrochemistry, 28: 201-207 (1998). 19. grau. j. m and. bisang j. m, , removal of cadmium from dilute aqueous solutions with a rotating cylinder electrode of expanded metal, j. chem. technol. biotechnol., 78: 1032 (2003). available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.20 no.4 (december 2019) 15 – 20 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: shafaa d. mohammed , email: shafaadhyaa@gmail.com , name: muthana j. ahmed, email: muthannaj@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. enhanced conversion of glycerol to glycerol carbonate on modified bio-char from reed plant shafaa d. mohamme and muthana j. ahmed university of baghdad college of engineering –chemical engineering department abstract the surplus glycerol produced from biodiesel production process as a by-product with high quantity can be considered as a good source to prepare glycerol carbonate (gc) whereas with each 1000 kg from biodiesel obtains 100 kg from glycerol. the aim of this paper is studying the possibility of converting the glycerol to glycerol carbonate using the bio-char prepared from reed plant as a catalyst. the catalyst was prepared at different temperatures ranging from 400-800°c. the results show that the biochar prepared at 700 ᴼc gives a best one among the others types of bio-char, but the yield was increased to 67.80% using prepared bio-char and when the catalyst promoted by sodium hydroxide, the obtained yield reached to 98.3% and complete conversion. in this study, the complete conversion was achieved at optimum conditions which were 60ᴼc, 90 min, 3:1 dmc:g , 3%wt. catalyst loading and using bio-char modified with 3 molar naoh . keywords: glycerol carbonate, glycerol, pyrolysis, trans esterification reaction, biochar received on 07/07/2019, accepted on 15/09/2019, published on 30/12/1029 https://doi.org/10.31699/ijcpe.2019.4.3 1introduction biodiesel has involved significant consideration as an alternative to the fossil fuel resources. u.s. government and european union have broadcast obligatory rules for the use of biodiesel in transportation on-road diesel and fuel. though, production of biodiesel by plant oil methanolysis produces large quantity of glycerol (about 10 wt. %) as an inevitable by-product that has to be valorized to progress the monetary attractiveness of biodiesel. consequently, transformation of glycerol into valuable products is of excessive significance. so far, numerous routes for glycerol translation have been stated like: reduction, selective oxidation, esterification, etherification, transesterification, and polymerization ‎[1]. biodiesel is a harmless fuel with great biodegradability, better lubrication, and combustion efficiency. it can be formed from animal fats, oils, algal, and plant ‎[2]. usually, 1 mol of triglyceride containing fats and oils reacted with 3 mol of alcohol particularly methanol to provide 3 mol of fatty acid methyl ester fame that is named biodiesel, and 1 mol of glycerol result ‎[3]. therefore, the creation of every 1000 kg of biodiesel yields by-product of glycerol around 100 kg ‎[4]. biodiesel production in 2016 reached 37 billion gallons as indicated by oil world's gauge. so, around 4 billion gallons of glycerol will be delivered that year ‎[5]. it is usually recognized that glycerol has an extensive diversity of applications and usages like: pharmaceutical, perfumery, food, cosmetic, and coating ‎[6]. furthermore, glycerol itself is very inexpensive and most use needs added refining process. later, the glycerol transformation to other important synthetic substances like esters of glycerol, glycerol carbonate, propane diols, glyceric acid, and acrolein will create included an incentive for glycerol, yet additionally advance biodiesel generation ‎[5] ‎[7] ‎[8]. glycerol is a non-flammable, non-toxic, readily biodegradable, water-soluble viscous liquid which is produced in the modern oleo chemical industry as a coproduct via a variety of processes including alcoholysis, saponification, as well as dedicated synthesis processes from propene and fermentation of sugars ‎[9],‎[10]. lately, scientists have changed glycerol into a multitude of high valuable substances like propanediols, ethers, glycerol carbonate (gc), and bulk chemicals ‎[11]. (gc) is an important multi-functional complex used as additive, solvent, and creates a block in substitute chlorine-free procedures ‎[12]. gc is such a substance that has been extensively used in gas-separation membranes, paints, and solvent for therapeutic research and personal care products due to its low flammability, worthy bio-degradability, low toxicity, slight viscosity, high boiling point, and water solubility. also, gc has strained greatly care in the few last year’s owing to its possible manufacturing uses in the preparation of polyurethanes ‎[13]. for these significant features, it detections many uses in diverse industrial parts, particularly as a glacial great hot solvent or middle in organic syntheses (i.e., synthesis of additional polymeric and polycarbonates constituents in https://doi.org/10.31699/ijcpe.2019.4.3 s. d. mohammed and m. j. ahmed / iraqi journal of chemical and petroleum engineering 20,4 (2019) 15 20 61 the plastics arena employed in plastics, textile, cosmetics, and pharmaceutical industries), as a forerunner in biomedical uses and as a protection group in carbohydrate chemistry. it is also used as a constituent in membranes for instead of ethylene, in the synthesis of polyurethanes, gas separation, and in the production of surfactants, propylene carbonates. finally, glycerol carbonate and its derivatives it reflected to be a green extra for significant petroderivative compounds (propylene carbonate or ethylene carbonate) ‎[14]. as described previously in the previous studies, glycerol can also directly or indirectly be converted to glycerol carbonate via a number of routes reacting with a “co” source. these sources include, urea, ethylene carbonate, alkyl carbonates, as well as co2 ‎[10]. the drawbacks of formation gc from urea and glycerol achieved by creation great quantities of ammonia and the difficulty in extrication the undesired by-products such as: biuret and isocyanic acid. glycerol carbonate may be produced from ethylene carbonate and glycerol via transesterification reaction but the high boiling points of ethylene glycol as a by-product which makes the separation of products hard. comparison with these ways, transesterification of dimethyl carbonate (dmc) with glycerol for gc preparation is reflected as the talented and most preferable method for industrial use due to the easy separation of byproduct, mild reaction conditions, high gc produce, and simple process ‎[1]. a wide range of catalytic systems have demonstrated effective synthesis of glycerol carbonate, including both heterogeneous and homogeneous catalysts as well as enzymatic processes. the development of heterogeneous catalysts with worthy strength and high action is extremely wanted ‎[15]. between the probable catalysts which can be used, bio-char achieve high performance for valorization, prepared by pyrolysis method from utilization of renewable source (reed plant) was used to catalyze transesterification reaction and it can be considered a highly efficient heterogeneous catalyst easy to separate and recycle. fig. 1. transesterification reaction to produce glycerol carbonate 2experimental work 2.1. char manufacturing catalyst produced depending on pyrolysis technique, char was used to activate the reaction which was manufactured from reed plant as raw material. firstly, reed plant was washed twice with deionized water instead of raw water to prevent increasing impurities in pore sites then dried for 6 hr by dryer under (110 ˚c) before uses. then it was cut, crushed and grind, after grinding the reed plant particles sieved by sieve size (600 and 1200) micrometer to obtain the particle size around (600 – 1200) micrometer, bio-char prepared by pyrolysis process under different temperature from 400 800 ˚c for 1 hr in absence or very low oxygen . grinding and sieving to size (600 and 1200) micrometer biochar (400-800) ᴼc fig. 2. reed plant particles and prepared bio-char 2.2. characterization a. bet and pore volume the surface area and pore volume measurement were performed by the ministry of oil, petroleum r and d center by using astm d1993 accelerated surface area and porosimetry system. the knowledge of the specific surface, is of great importance in the characterization of a powder or a solid (extruded or beads), regardless of the areas of application. it helps to improve the control of the reactivity of a sample when it is in the presence of other materials. in the bet measurement, the mixture of nitrogen with helium will pass through a channel for thermal conductivity detector, the detector to sample flow through a glass cell and then pass into analytical channel that is a thermal conductivity detector. sign of detector was indicated by microprocessor control board, and then saved in a memory file. the procedure of test began when degassing the sample by a carrier gas at a programming temperature. during the drying of operator transfer the holder of the sample to the analytical port and then fitted them with specified place by basis quick fit connectors. turning on the bottom should raise the nitrogen flask carriage will initiate the analysis. desorption and adsorption of the gas measured with a highly sensitive thermal conductivity detector. high sensitivity will be used for a low surface area begin from 0.1 m2/g. if the sample with the large surface area, then the thermal conductivity detector give wide range of signal response. s. d. mohammed and m. j. ahmed / iraqi journal of chemical and petroleum engineering 20,4 (2019) 15 20 61 2.3. glycerol carbonate production procedure the reaction of glycerol and dimethyl carbonate was performed in a three neck around bottom flask reactor ( of 50 ml) equipped with a condenser, and established in a water bath over hot plate with magnetic stirrer stirring with (150 rpm), and two thermometer for monitoring temperature one of them in flask and the another one in water bath. char prepared at various pyrolysis temperatures used to catalyze the reaction. the mixture of biochar catalyst and glycerol was heated to reach the reaction temperature and then added dimethyl carbonate. the reaction performed at conditions 3:1 dmc :g ratio,60 ˚c ,90 min ,150 rpm and 3% weight percent catalyst loading ,these conditions selected as a mid-points in the studied variables 5:1 dmc :g ratio, (40 80) ˚c , (30 -150) min , (1 – 5)% weight percent catalyst loading and 150 rpm. hplc (high performance liquid chromatography) was used for analyzing purpose. fig. 3. photographic picture of experimental work for gc synthesis 2.4. catalyst modification procedure modification of catalyst was required in case of want to meet complete conversion and highly yield due to enhance the surface area of active sites. it is important to investigate the effect of base molar concentration on improvement the catalyst activity ‎[16] to give high glycerol carbonate yield, different molar concentration (1, 2 and 3) m from naoh was used in char modification. bio-char was modified as described in ‎[16] by immersing (1.0 g) of bio-char in 20 ml of different molar concentration (1 3) molarity sodium hydroxide solution, then was shaked for 24 hr at 120 rpm. filtration was performed for solid separation from liquid, after that washed with deionized water till neutral ph was obtained and dried for 24 hr at 110 ᴼc. the modified bio-char used in the study with operating condition (3:1 ratio dmc: glycerol, 60˚c, 90 min, 150 rpm and 3% weight per cent catalyst) these conditions selected as a mid-points in the studied variables 5:1 dmc :g ratio, (40 80) ˚c , (30 -150) min , (1 – 5)% weight percent catalyst loading and 150 rpm to investigate which molar concentration of naoh have more effect increase the catalytic activity of bio-char. 3results and discussion 3.1. effect of pyrolysis temperature on bio-char yield% fig. 4. effect of pyrolysis temperature on bio-char yield% preliminarily the influence of pyrolysis temperature on the yield of bio-char must be investigated by study effect of different temperatures on prepared char from reed plant. fig. 4 shows the results of the present study and show the effect of difference in pyrolysis temperature on 2 g of reed particles, obviously there is a continuous reduction in the weight of char and this is observed at each 100ᴼ c which was increased. when the reed particles combusted at pyrolysis temperature 400ᴼ c the char yield gained 33.75% and when the pyrolysis temperature increased to 500ᴼ c and the yield obtained which decreased dramatically to 31.55%. this gives an indication that when the pyrolysis temperature increased the volatile element like hydrogen, nitrogen decreased also the water content will decrease with temperature increasing. when the pyrolysis temperature became 600ᴼc the char yield slightly decreased to 29.59%, in temperature 700ᴼc and 800ᴼc the yield obtained was 21.36% ,9.27% respectively, so approximately the char yield reached to the quarter yield of char which was prepared at 400ᴼc. increasing in pyrolysis temperature causes a in rise the ash and fixed c contents, also lowering of volatile materials content (hydrogen and oxygen) readily due to the weaker bonds in the volatile constituents ‎[17]. optimum bio char yield obtained in this study at the lower pyrolysis temperature 400ᴼ c. 0.00% 5.00% 10.00% 15.00% 20.00% 25.00% 30.00% 35.00% 40.00% 400 600 800 1000 c h a r y ie ld % temperature,ᴼc s. d. mohammed and m. j. ahmed / iraqi journal of chemical and petroleum engineering 20,4 (2019) 15 20 61 bio-char yield% the yield of char used for indication the process efficiency for the chemical activation process. the char yield was calculated as the weight percentage of the manufactured char divided by the weight of the grinded reed. y𝑖𝑒𝑙𝑑% = wei/weig ×100 𝑤𝑒𝑖 (𝑔) is weight of char 𝑤𝑒𝑖𝑔 (g) is weight of 𝑟𝑎𝑤 material 3.2. effect of prepared char at various pyrolysis temperatures on gc yield% and g conversion% fig. 5. effect of prepared char at various pyrolysis temperatures on gc yield% and g conversion% after preparation of char at different pyrolysis temperature from 400ᴼc to 800ᴼc, the catalytic activity of the prepared char was investigated by transesterification process of glycerol with dimethyl carbonate and to show the influence of prepared bio-char on glycerol carbonate yield and glycerol conversion. the reaction was carried out under mild conditions temperature 60ᴼ c, 3:1 dmc: g ratio, 150 rpm and 3% wt. catalyst loading in time of 90 min ,all results illustrate in fig. 5. when the char was manufactured at 400 ᴼc , the obtained gc yield and g conversion was very low (below 20%),after that char was prepared with 500ᴼc used in catalyze the reaction to make a slight increasing in gc yield (19.683%) and g conversion (26.53%). gc yield and g conversion was obtained from catalyze the reaction with char prepared at pyrolysis temperature 600ᴼc were 20.48%, 34.17% respectively. the prepared char at 700ᴼc has been shown a dramatic increasing in yield and conversion until reach 54.16%, 69.81% respectively. in each increasing in bio-char preparation temperature causes dramatic increase in gc yield an g conversion this can belong to increasing the active sites numbers and catalytic surface area of bio-char catalyst causes increment in gc yield an g conversion . the highest values for yield and conversion were obtained when the reaction catalyze with bio-char prepared with 800 ᴼc pyrolysis temperature but the difference in values of gc yield and g conversion between the two bio-char prepared at temperature (700 ᴼc and 800 ᴼc) is very slight and to reduce in energy and cost , the bio-char prepared at 700ᴼc used for catalyzing transesterification reaction .finally to enhance the char activity ,the selected bio-char immersed in (0.1 m) hcl for 24 hr to remove impurities from char pores after that washed with deionized water for neutralization purpose to be ready for catalyzing glycerol transesterification reaction then found a good increasing in gc yield happened reach it to 67.8% and g conversion reached to 76.3%, the increment in gc yield and g conversion belonged to clearance the active sites from impurities when the char washed with (0.1 m) hcl. 3.3. effect of modified bio-char by different naoh molar concentration on gc yield% and g conversion% fig. 6. effect of different naoh molar concentration on catalytic activity fig. 6 explain all results of glycerol carbonate yield and glycerol conversion at different molar concentrations of naoh under time 90 min , temperature 60 ᴼc, dimethyl carbonate : glycerol ratio 3:1 dmc:g ratio and 3%wt. used from catalyst loading. from the figure observed that each increasing in naoh concentration which was used for catalyst modification there was increasing in gc yield and g conversion. complete conversion of glycerol was achieved by enhancing the catalyst with 3 m naoh also high yield of gc obtained 98.32%,the increment in yield belonged to enhancing the activity of catalyst when modified with sodium hydroxide base by increasing the number of hydroxyl group oh as described in ‎[18] and this was regarded as a major reason to initiate the reaction between the proton of weak acid from one of the two primary hydroxyl group of glycerol with the base catalyst ,this is mean in each increasing in naoh concentration the hydrouxyl groups number increment and the gc yield and g conversion also increased . s. d. mohammed and m. j. ahmed / iraqi journal of chemical and petroleum engineering 20,4 (2019) 15 20 61 3.4. surface area and pore volume the obtained bet surface area and total pores volume of prepared bio-char from reed plant particles are 214.1487 m 2 /g and 0.1204 cm 3 /g respectively, so the results show good surface characterization for transesterification process .the surface area and pore volume of char produced from different feedstock clarified in the table below: table 1. specifications of char from different feedstock feedstock surface area pore volume references cotton stalk 224 0.070 ‎[19] pine wood 209.6 0.009 ‎[20] bamboo 351 0.130 ‎[21] 4conclusion reaction of glycerol with dimethyl carbonate is performed by catalyzing the reaction with bio-char as a heterogeneous catalyst. char catalyst prepared from reed plant as a natural source by pyrolysis technique under different temperatures from 400°c to 800°c, in each increasing in pyrolysis temperatures the yield of char decrease. the highest values for gc yield and g conversion were obtained when the reaction catalyze with bio-char prepared at 800 ᴼc pyrolysis temperature but the difference in values of gc yield and g conversion between the two prepared bio-char at temperatures (700 ᴼc and 800 ᴼc) is very slight also to reduce the energy cost select bio-char prepared at 700ᴼc. the char prepared at 700ᴼc give 54.16 % gc yield and 69.81% g conversion. when the selected catalyst immersed in (0.1 m) hcl for 24 hr and washed with deionized water for neutralization purpose found a good increasing in gc yield happened reach it to 67.8% and conversion reached to 76.3%. the catalyst modification with 3 m naoh shows enhance in catalyst activity to give high yield of gc reached to 98.32% and complete conversion achieved, all the reactions carried out under conditions 90 min, 60 ᴼc, 3:1 dmc:g ratio and 3%wt. used from catalyst loading. references [1] liu, z., wang, j., kang, m., yin, n., wang, x., tan, y. and zhu, y., 2014. synthesis of glycerol carbonate by transesterification of glycerol and dimethyl carbonate over kf/γ-al2o3 catalyst. journal of the brazilian chemical society, 25(1), pp.152-160. [2] witoon, t., bumrungsalee, s., vathavanichku, p., palitskun, s., saisriyoot, m. and faungnawakij, k. (2014). biodiesel production from transesterification of palm oil with methanol over cao supported on bimodal meso-macroporous silica catalyst. bioresource technology. 156: 329-334. [3] roschat, w., siritanon, t., yoosuk, b. and promarak, v. (2016). biodiesel production from palm oil using hydrated lime-derived cao as a low-cost basic heterogeneous catalyst. energy conversion and management. 108: 459-467. [4] malyaadri, m., jagadeeswaraiah, k., sai-prasad, p. s. and n. lingaiah. (2011). synthesis of glycerol carbonate by transesterification of glycerol with dimethyl carbonate over mg/al/zr catalysts. applied catalysis a: general. 401: 153-157. [5] rastegari, h. and ghaziaskar, h. s. (2015). from glycerol as the byproduct of biodiesel production to value-added monoacetin by continuous and selective esterification in acetic acid. journal of industrial and engineering chemistry. 21: 856-861. [6] roschat, w., kacha, m., yoosuk, b., sudyoadsuk, t. and promarak, v. (2012). biodiesel production based on heterogeneous process catalyzed by solid waste coral fragment. fuel. 98:194-202. [7] zheng, l., xia, s., lu, x. and hou, z. (2015). transesterification of glycerol with dimethyl carbonate over calcined ca-al hydrocalumite. chinese journal of catalysis. 36: 1759-1765. [8] zhou, y., ouyang, f., song, z. b., yang, z. and tao, d. j. (2015). facile one-pot synthesis of glycidol from glycerol and dimethyl carbonate catalyzed by tetraethylammonium amino acid ionic liquids. catalysis communications. 66: 25-29. [9] dibenedetto, a., angelini, a., aresta, m., ethiraj, j., fragale, c. and nocito, f. (2011). converting wastes into added value products: from glycerol to glycerol carbonate, glycidol and epichlorohydrin using environmentally friendly synthetic routes. tetrahedron. 67: 1308-1313. [10] stewart, j.a., 2015. towards green cyclic carbonate synthesis: heterogeneous and homogeneous catalyst development (doctoral dissertation, utrecht university). [11] du, y., gao, j., kong, w., zhou, l., ma, l., he, y., huang, z. and jiang, y., 2018. enzymatic synthesis of glycerol carbonate using a lipase immobilized on magnetic organosilica nanoflowers as a catalyst. acs omega, 3(6), pp.6642-6650. [12] chiappe, c. and rajamani, s., 2011. synthesis of glycerol carbonate from glycerol and dimethyl carbonate in basic ionic liquids. pure and applied chemistry, 84(3), pp.755-762. [13] algoufi, y. t., akpan, u. g., asif, m. and hameed, b. h. (2014). one-pot synthesis of glycidol from glycerol and dimethyl carbonate over kf/sepiolite catalyst. applied catalysis a: general. 487: 181-188. [14] wang, s., hao, p., li, s., zhang, a., guan, y. and zhang, l., 2017. synthesis of glycerol carbonate from glycerol and dimethyl carbonate catalyzed by calcined silicates. applied catalysis a: general, 542, pp.174-181. [15] wang, y., liu, c., sun, j., yang, r. and dong, w., 2015. ordered mesoporous baco 3/c-catalyzed synthesis of glycerol carbonate from glycerol and http://www.scielo.br/scielo.php?pid=s0103-50532014000100019&script=sci_arttext&tlng=pt http://www.scielo.br/scielo.php?pid=s0103-50532014000100019&script=sci_arttext&tlng=pt http://www.scielo.br/scielo.php?pid=s0103-50532014000100019&script=sci_arttext&tlng=pt http://www.scielo.br/scielo.php?pid=s0103-50532014000100019&script=sci_arttext&tlng=pt http://www.scielo.br/scielo.php?pid=s0103-50532014000100019&script=sci_arttext&tlng=pt https://www.sciencedirect.com/science/article/pii/s0960852414001011 https://www.sciencedirect.com/science/article/pii/s0960852414001011 https://www.sciencedirect.com/science/article/pii/s0960852414001011 https://www.sciencedirect.com/science/article/pii/s0960852414001011 https://www.sciencedirect.com/science/article/pii/s0960852414001011 https://www.sciencedirect.com/science/article/pii/s0960852414001011 https://www.sciencedirect.com/science/article/pii/s0196890415010560 https://www.sciencedirect.com/science/article/pii/s0196890415010560 https://www.sciencedirect.com/science/article/pii/s0196890415010560 https://www.sciencedirect.com/science/article/pii/s0196890415010560 https://www.sciencedirect.com/science/article/pii/s0196890415010560 https://www.sciencedirect.com/science/article/abs/pii/s0926860x11002882 https://www.sciencedirect.com/science/article/abs/pii/s0926860x11002882 https://www.sciencedirect.com/science/article/abs/pii/s0926860x11002882 https://www.sciencedirect.com/science/article/abs/pii/s0926860x11002882 https://www.sciencedirect.com/science/article/abs/pii/s0926860x11002882 https://www.sciencedirect.com/science/article/abs/pii/s1226086x14002214 https://www.sciencedirect.com/science/article/abs/pii/s1226086x14002214 https://www.sciencedirect.com/science/article/abs/pii/s1226086x14002214 https://www.sciencedirect.com/science/article/abs/pii/s1226086x14002214 https://www.sciencedirect.com/science/article/abs/pii/s1226086x14002214 https://www.sciencedirect.com/science/article/pii/s0016236112002736 https://www.sciencedirect.com/science/article/pii/s0016236112002736 https://www.sciencedirect.com/science/article/pii/s0016236112002736 https://www.sciencedirect.com/science/article/pii/s0016236112002736 https://www.sciencedirect.com/science/article/pii/s1872206715609159 https://www.sciencedirect.com/science/article/pii/s1872206715609159 https://www.sciencedirect.com/science/article/pii/s1872206715609159 https://www.sciencedirect.com/science/article/pii/s1872206715609159 https://www.sciencedirect.com/science/article/pii/s1566736715001065 https://www.sciencedirect.com/science/article/pii/s1566736715001065 https://www.sciencedirect.com/science/article/pii/s1566736715001065 https://www.sciencedirect.com/science/article/pii/s1566736715001065 https://www.sciencedirect.com/science/article/pii/s1566736715001065 https://www.sciencedirect.com/science/article/abs/pii/s0040402010017461 https://www.sciencedirect.com/science/article/abs/pii/s0040402010017461 https://www.sciencedirect.com/science/article/abs/pii/s0040402010017461 https://www.sciencedirect.com/science/article/abs/pii/s0040402010017461 https://www.sciencedirect.com/science/article/abs/pii/s0040402010017461 https://www.sciencedirect.com/science/article/abs/pii/s0040402010017461 https://dspace.library.uu.nl/handle/1874/325586 https://dspace.library.uu.nl/handle/1874/325586 https://dspace.library.uu.nl/handle/1874/325586 https://dspace.library.uu.nl/handle/1874/325586 https://pubs.acs.org/doi/abs/10.1021/acsomega.8b00746 https://pubs.acs.org/doi/abs/10.1021/acsomega.8b00746 https://pubs.acs.org/doi/abs/10.1021/acsomega.8b00746 https://pubs.acs.org/doi/abs/10.1021/acsomega.8b00746 https://pubs.acs.org/doi/abs/10.1021/acsomega.8b00746 https://www.degruyter.com/view/j/pac.2012.84.issue-3/pac-con-11-07-06/pac-con-11-07-06.xml https://www.degruyter.com/view/j/pac.2012.84.issue-3/pac-con-11-07-06/pac-con-11-07-06.xml https://www.degruyter.com/view/j/pac.2012.84.issue-3/pac-con-11-07-06/pac-con-11-07-06.xml https://www.degruyter.com/view/j/pac.2012.84.issue-3/pac-con-11-07-06/pac-con-11-07-06.xml https://www.sciencedirect.com/science/article/abs/pii/s0926860x14005687 https://www.sciencedirect.com/science/article/abs/pii/s0926860x14005687 https://www.sciencedirect.com/science/article/abs/pii/s0926860x14005687 https://www.sciencedirect.com/science/article/abs/pii/s0926860x14005687 https://www.sciencedirect.com/science/article/abs/pii/s0926860x14005687 https://www.sciencedirect.com/science/article/abs/pii/s0926860x17302193 https://www.sciencedirect.com/science/article/abs/pii/s0926860x17302193 https://www.sciencedirect.com/science/article/abs/pii/s0926860x17302193 https://www.sciencedirect.com/science/article/abs/pii/s0926860x17302193 https://www.sciencedirect.com/science/article/abs/pii/s0926860x17302193 https://link.springer.com/article/10.1007/s11426-014-5173-0 https://link.springer.com/article/10.1007/s11426-014-5173-0 https://link.springer.com/article/10.1007/s11426-014-5173-0 s. d. mohammed and m. j. ahmed / iraqi journal of chemical and petroleum engineering 20,4 (2019) 15 20 02 dimethyl carbonate. science china chemistry, 58(4), pp.708-715. [16] wan, m.-w., petrisor, i. g., lai, h.-t., kim, d., & yen, t. f., (2004)," copper adsorption through chitosan immobilized on sand to demonstrate the feasibility for in situ soil decontamination", carbohydrate polymers, 55(3), 249–254. [17] paethanom, a., & yoshikawa, k., (2012),"influence of pyrolysis temperature on rice husk char characteristics and its tar adsorption capability", energies, 5(12), 4941–4951. [18] paul,j. and shunnian,wu.,2004,"acid/basetreated activated carbon:characterization of functional groups and metal adsorptive properties",langmuir,vol 20,pp. 2233-2242. [19] zhang, x., zhang, s., yang, h., feng, y., chen, y., wang, x., chen, h., 2014. nitrogen enriched biochar modified by high temperature co2-ammonia treatment: characterization and adsorption of co2. chem. eng. j. 257, 20-27. [20] wang, s., gao, b., zimmerman, a.r., li, y., ma, l., harris, w.g., migliaccio, k.w., 2015b. removal of arsenic by magnetic biochar prepared from pinewood and natural hematite. bioresour. technol. 175, 391-395. [21] yao, y., gao, b., fang, j., zhang, m., chen, h., zhou, y., creamer, a.e., sun, y., yang, l., 2014. characterization and environmental applications of clayebiochar composites. chem. eng. j. 242, 136-143. تحسين تحويل الكميسرول الى كميسرول كاربونيت بأستخدام الفحم الحيوي المحسن نبات القصبوالمنتج من شفاء ضياء و مثنى جبار قسم اليندسة الكيمياوية-كمية اليندسة-جامعة بغداد الخالصة النتاج مادة عد الكميسرول الفائض من عمميات انتاج البايوديزل كمنتج ثانوي بكميات ىائمو مصدر جيد ي .كيموغرام من الكميسرول 011قريبا كيموغرام من البايوديزل يصاحبيا ت 0111الكميسرول كاربونيت حيث ان كل اليدف من ىذا البحث ىو دراسة احتمالية تحويل الكميسرول الى كميسرول كاربونيت بأستخدام الفحم الحيوي وقد درجة مئوية °800الى400.يتم تحضير العامل المساعد بحرارات مختمفو من المحضر من نبات القصب درجة مئوية يعد االفضل من بين انواع الفحم ° 700اظيرت النتائج ان الفحم المحضر بالدرجو الحراريو % بأستخدام الفحم الحيوي المحضر وعندما تم تحسين العامل 67 ,01.لكن االنتاجية زادت الى المحضره % وتحول تام .في ىذه الدراسة يتم 98.3المساعد باستخدام ىيدروكسيد الصوديوم فأن االنتاجية وصمت الى % نسبة 3, نسبة الكميسرول:الداي مثيل كاربونيت 1:3دقيقة ، 90درجة مئوية ،°60تحقيق تحول تام بظروف .من ىيدروكسيد الصوديوم موالري 3واستخدام الفحم الحيوي المحسن ب تحميل العامل المساعد حمل الحراري, الفحم الحيوي.الكممات الدالة: كميسرول كاربونيت, كميسرول, الت https://link.springer.com/article/10.1007/s11426-014-5173-0 https://link.springer.com/article/10.1007/s11426-014-5173-0 https://www.sciencedirect.com/science/article/pii/s0144861703002777 https://www.sciencedirect.com/science/article/pii/s0144861703002777 https://www.sciencedirect.com/science/article/pii/s0144861703002777 https://www.sciencedirect.com/science/article/pii/s0144861703002777 https://www.sciencedirect.com/science/article/pii/s0144861703002777 https://www.mdpi.com/1996-1073/5/12/4941 https://www.mdpi.com/1996-1073/5/12/4941 https://www.mdpi.com/1996-1073/5/12/4941 https://www.mdpi.com/1996-1073/5/12/4941 https://pubs.acs.org/doi/abs/10.1021/la0348463 https://pubs.acs.org/doi/abs/10.1021/la0348463 https://pubs.acs.org/doi/abs/10.1021/la0348463 https://pubs.acs.org/doi/abs/10.1021/la0348463 https://www.sciencedirect.com/science/article/pii/s1385894714009036 https://www.sciencedirect.com/science/article/pii/s1385894714009036 https://www.sciencedirect.com/science/article/pii/s1385894714009036 https://www.sciencedirect.com/science/article/pii/s1385894714009036 https://www.sciencedirect.com/science/article/pii/s1385894714009036 https://www.sciencedirect.com/science/article/pii/s0960852414015363 https://www.sciencedirect.com/science/article/pii/s0960852414015363 https://www.sciencedirect.com/science/article/pii/s0960852414015363 https://www.sciencedirect.com/science/article/pii/s0960852414015363 https://www.sciencedirect.com/science/article/pii/s0960852414015363 https://www.sciencedirect.com/science/article/pii/s1385894713016434 https://www.sciencedirect.com/science/article/pii/s1385894713016434 https://www.sciencedirect.com/science/article/pii/s1385894713016434 https://www.sciencedirect.com/science/article/pii/s1385894713016434 iraqi journal of chemical and petroleum engineering vol.16 no.1 (march 2015) 6369 issn: 1997-4884 corrosion of electrical submersible pumps (esp) in south rumaila oil field dr. talib abdullah saleh, *dr. safaa husain sahi and layla sideeq mohamed petroleum engineering department/university of baghdad *ministry of oil abstract rotating cylinder electrode (rce) is used . in weight loss technique , the salinity is 200000 p.p.m, temperatures are (30,5060,7080co) . the velocity of (rce) are (500,1500,3000 r.p.m). the water cut (30% , 50%). the corrosion rate of carbon steel increase with increasing rotating cylinder velocity. in single phase flow, an increase im rotational velocity from 500 to 1500 r.p.m, the corrosion rate increase from 6.88258 mm/y to 10.11563 mm/y respectively. in multiphase flow, an increase in (rce) from 500 to 1500 r.p.m leads to increase in corrosion rate from 0.786153 to 0.910327 mm/y respectively. increasing brine concentration leads to increase in corrosion rate at water cut 30%. key words: rotating cylinder electrode, weight loss, polarization, protective film. introduction corrosion is an important and costly problem in the petroleum industry, requiring special consideration in the design of production equipment. severe environments involving co2 and h2s pose particular difficulties. corrosion cost the petroleum industry hundreds of millions of dollars annually. water flood, co2 flood, deep gas wells are excellent examples of cases have provided many materials and corrosion problems are expected to continue to do so [1]. corrosion rate in neutral, low salinity solution is normally very low. in contrast, corrosion rates are very high in low ph solution that forms the presence of acidic materials or high co2 partial pressure [2]. most of the southern iraqi oil fields produced large quantities of water, often a brine, with produced oil. this water has high salinity about 200,000 ppm in addition to this brine, compounds such as carbone dioxide (co2), h2s, oxygen mineral acids, organic acids or other chemicals that affect ph, these corrodants are highly corrosive to the carbon steel which has low resistance to the corrosion, these compounds combine to form a corrosive environment under different environmental conditions. carbone dioxide (co2) corrosion also known as sweet corrosion is one of the major problems in the oil and gas industry costing billions of dollars every year [3] .corrosion in gas and oil industries mainly deals with co2 gas, as it is the species presenting in oil field. the hydration of co2 to carbonate acid causes corrosion on carbone steel [4]. it is due to carbonate acid can decrease ph of the medium. degree of iraqi journal of chemical and petroleum engineering university of baghdad college of engineering corrosion of electrical submersible pumps (esp) in south rumaila oil field 64 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net corrosiveness due to co2 gas influenced by environmental conditions such as temperature, co2 partial pressure, corrosion film properties and flow conditions. due to its low cost and availability, carbone steel is used as the primary construction material for pipelines in the oil and gas industries and electrical submersible pumps, but it is very susceptible to corrosion in co2 environment. aqueous carbone dioxide (carbonic acid) is corrosive and corrodes the carbone steel pipelines and esp [5] experiment setup specimen preparation a rotating cylinder electrode (rce) is a cylindrical material embedded in to a non-conducting material such as teflon, and attached to an electric motor with a controlled rotation speed. the working electrodes were carbon steels, before every test the specimens washing with running tap water, cleaned with emery paper of grades 100, 150, 200, 320, 400 and 600 to remove the weakly adherent corrosion scale, washed by tap water, rinsed with distilled water, dried with a rotating cylinder electrode (rce) is a cylindrical material embedded in to a non-conducting material such as teflon, and attached to an electric motor with a controlled rotation speed. the working electrodes were carbon steels, before every test the specimens washing with running tap water, cleaned with emery paper of grades 100, 150, 200, 320, 400 and 600 to remove the weakly adherent corrosion scale, washed by tap water, rinsed with distilled water, dried with kleenex tissue, then rinsed with ethanol for 10 minutes, after that dried with kleenex followed by rinsing with acetone, dried with kleenex, then left to dry for 24 hour in a desiccator over silica gel. some of the experiments were repeated in order to obtain the reproducible results. rotating cylinder electrode showed in fig. (1). fig. 1, rotating cylinder electrode cell solutions the experiments were performed in both single phase (brine of salinity 200,000 ppm) and multiphase flow by injection gas co2 into the solution. in single-phase flow, the glass cell was filled with 2 liter of brine of salinity 200,000 ppm nacl, while in multiphase flow the glass filled with different percents of brine with kerosene, which was stirred with motor. weight loss technique system was shown in fig. (2) corrosion rate measurement a. weight loss technique weight loss was used to measure the corrosion rate of the metal. during weight loss technique, the specimens were prepared as described above, and corrosion rate measured by weighting the specimens before and after each test, corrosion rate can be obtained from eq.(1) dr. talib abdullah saleh and layla sideeq mohamed -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 65 c.r(mdd)= fig. 2, weight loss technique system:1rotating motor 2-rotating shaft 3working electrode 4-thermometer 5beaker 6-water bath 7-co2 distributed 8gas flow meter 9-one way valve 10pressure gauge 11-co2 source 12-high pressure tube. results and discussion of weight loss results 1. effect of ph the higher ph, the lower is the corrosion rate. the ph is influenced by changing the h + ions concentration, temperature and pressure, the increase of ph causes film thickening and film becoming more dense and protective. in the present investigation, the system is under the summation of both an appreciable rate of hydrogen evolution and oxygen depolarization because ph values were less than 4 [6] 2h + +2e→h2 ...(2) 2h2co3 +2e → 2hco 3 + h2 ... (3) 2hco 3 + 2e → 2co 3 +h2 ...(4) 2h2o + 2e → 2oh +h2 …(5) while oxygen reduction is expressed by the eq.(6) o2 + 4h+ + 4e → 2h2o …(6) an increase in temperature leads to an increase in ph values as a result of decreasing in the solubility of co2 gas so leading in decreasing in the acidity of the solution as shown in fig. (3) fig.3, the relationship between ph and temperature at water cut= 30% and different co2 flow rates 2. effect of temperature corrosion likes any chemical reaction increases with an increase in the temperature, corrosion rates reach maximum value at 70° c then it start to decrease with farther increase in temperature from 70-80° c due to the formation of the protective film (iron carbonate) on the metal surface, this film protect the metal from the contact with the corrosive aqueous solution, and the other reason is due to the reduction of oxygen solubility in the solution as shown in fig.(4). fig.4, the relationship between the corrosion rate and the temperatue at p h temperature (°c) co rr o si o n r a te ( m d d ) temperature (°c) corrosion of electrical submersible pumps (esp) in south rumaila oil field 66 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net different velovities for single phase flow 3. effect of co2 partial pressure an increase in co2 partial pressure leads to an increase in corrosion rate as shown in fig. (5). fig.5, the relationship between co2 partial pressure and the corrosion rate for water cut 30%, co2 flow rate 0.0464 m 3 /hr and temperature 30 ° 4. effect of flow corrosion rate of the metal increases with an increase in fluid velocity, this is called erosioncorrosion and this occurs as a result of two causes the first one that is an increase in fluid velocity leads to an increase in the diffusion rate of active species in the solution to the metal surface, the second reason is that the high fluid velocity will decrease the diffusion boundary layer (thickness of the film through which oxygen must diffuse in the corrosion process as shown in fig. (6). fig.6, the relationship between the corrosion rate and rotating cylinder velocity at different temperatures at water cut=30% and co2 flow rate=0.0464m 3 /hr 5. effect of co2 flow rate an increase in co2 flow rate leads to reduce ph of the solution, which in turn lead to increase the corrosion rate by dissolving the protective film as shown in fig. (7). fig. 7, the relationship between co2 flow rate and corrosion rate at 30 ° c and wter cut = 30 % and at different velocities b. polarization technique in this technique the solutions and coupons preparation were similar to that in weight loss technique without weighting the coupons electrodes three-electrodes were used in all electrochemical experiments. a rotating cylinder electrode with a speed control unit was used as the working electrode. graphite was used as auxiliary electrode and a saturated calomel electrode (sce) used as reference electrode, which used to measure the potential of the working electrode. electrical apparatus the apparatus that used during polarization technique were dc power supply, resistance box; voltmeter was used to measure the potential of the c o rr o si o n r a te ( m m /y ) co2 partial pressure (bar) co rr o si o n r a te (m d d ) velocity (rpm) co rr o si o n r a te (m d d ) co2 flow rate(m 3/hr) dr. talib abdullah saleh and layla sideeq mohamed -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 67 electrode with respect to reference electrode, ammeter which used to measure the current of the cell. fig. (8a) and fig.(8.b) show the electrical cell of rotating cylinder electrode: fig.8, a rotating cylinder electrode (rce) electrical cell fig.8, b polarization system:1-power supply 2-resistance box 3-ammeter 4rotating motor 5-rotating shaft 6carbone brush 7-working electrode 8voltmeter 9-reference electrode 10one way valve 11-co2 source 12pressure gauge 13-thermometer 14auxilary electrode 15-beaker 16water bath 17-co2 distributed 18lugging-haber capillary 19-wires connection 20-high pressure tube corrosion rate measurement the experimental limiting current densities values are obtained by taking the average of points representing the concentration polarization in the tafel curve, tafel curve for co2 flow rate=0.1392m 3 /hr, temperature= 30 ºc and velocity=1500 rpm shown in fig. (9) fig.9, polarization diagram at co2 flow rate=0.1392m 3 /hr, temperature= 30 ºc and velocity=1500 rpm results and discussions of polarization technique  effect of temperature an increase in temperature leads to an increase in limiting current according to eq. (7) il = as shown in fig. (10) e ( m v ) i (µa/cm2) li m it in g c u rr e n t( µ a /c m 2 ) temperature(c°) corrosion of electrical submersible pumps (esp) in south rumaila oil field 68 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net fig. 10, the relationship between the temperature and the limiting current density at co2 flow rate=0.1392 m 3 /hr and at different velocities  effect of rotating cylinder electrode an increase in rotational velocity leads to an increase in limiting current as shown in fig. (11) fig. 11, the relationship between the velocity and limiting current density at co2 flow rate=0.1392 m 3 /hr and at different temperatures conclusions 1. weight loss technique: a. single phase flow  corrosion rates of the metal in the brine (200,000ppm nacl) are more than the corrosion rates in the multiphase flow (brine-co2kerosene) due to the dominate effect of oxygen diffusion comparing with the effect of the hydrogen evolution.  an increase in the rotating cylinder electrode velocity leads to an increase in the corrosion rate of the metal.  increasing the temperature of the solution from 30 to 70° c leads to an increase in the corrosion rate of the metal to reach maximum value at 70° c, and then it begins to falling to reach minimum rate at 80° c due to formation of the protective film at 70 ° c and as a result of decreasing the solubility of oxygen and the injected co2 in the solution.  the effect of rotating cylinder electrode velocity on corrosion rate is more than the effect of temperature. b. multiphase flow  through studying co2 corrosion mechanism, it can be concluded that co2 corrosion produce a very thin films. the film properties such as porosity, contour surface appearance and quality of the film change with time and influenced by solution compositions.  temperature and velocity approximately have combination effect on the corrosion rate of carbone steel.  an increase in brine concentration, lead to an increase in corrosion rate.  brine concentration has more influence on the corrosion rate compared to the temperature and rotating cylinder electrode velocity.  an increase in co2 flow rate led to an increase in corrosion rate.  corrosion rates of the metal at higher ph values less than the corrosion rates at lower ph values; the decrease of corrosion rate in the higher of ph is controlled by the film formation.  ph values of the solution were less than 4 and this means that the system was under the combination effect of hydrogen evolution and oxygen diffusion. 2. polarization technique:  an increase in rotating cylinder electrode velocity, lead to an increase in limiting current density, because when the li m it in g c u rr e n t( µ a /c m 2 ) velocity(rpm) dr. talib abdullah saleh and layla sideeq mohamed -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 69 velocity increase diffusion layer thickness will decrease which in turn leads to an increase in the limiting current density according to the eq.(7)  an increase in temperature, lead to an increase in limiting current density  co2 flow rate don’t have any influence on the anodic reaction  an increase in rotating cylinder electrode velocity lead to shifting the corrosion potential in the positive direction, while an increase in temperature of the solution lead to shifting the corrosion potential in the negative direction.  ph values of the solution were less than 4 and this means that the system was under the combination effect of hydrogen evolution and oxygen diffusion. nomenclatures a: area of the electrode c.r: corrosion rate esp: electrical submersible pumps w.l: weight loss technique rce: rotating cylinder electrode cs : surface concentration of the reaction species cb: bulck concentration of the reaction species = diffusion layer thickness n: the number of electrons transferred references 1. watfa; m.; aug. 1991, spe production engineering; no.8; p 283 2. nace, 1979, corrosion control in petroleum production; tpc publication; no.5; 3. nace, pdf (15 april 2009), corrosion cost and preventive strategies in the united states. http://events. nace. org. /publicffairs/ imagescorr/ccsupp. 4. james a. dougherty, (2004 ) " a review of the effect of organic acids on co2 corrosion annual conf., nace international, houston, texas, paper no. 04376 5. bilkova, k., gulbrandsen, e., acta 2008 "kinetic and mechanistic study of co2 corrosion inhibition by cetyl trimethyl ammonium bromide". electrochemical, 53 (16) 5423-5433) 6. whitmann, w., russel , r. and atlieri , v., ind. eng. chem., vol.16 , no. 7 , p665, 1924 http://events/ available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.20 no.3 (september 2019) 15 – 21 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: asaad salim bded , email: asaadsalim78@gmail.com, name: tahseen hameed khlaif, email:dr.alyasari@gmail.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. evaluation properties and pna analysis for different types of lubricants oils asaad salim bded and tahseen hameed khlaif petroleum engineering department, kerbala university, iraq abstract a study of characteristics of the lubricant oils and the physical properties is essential to know the quality of lubricant oils. the parameters that lead to classify oils have been studied in this research. three types of multi-grades lubricant oils were applied under changing temperatures from 25 o c to 78 o c to estimate the physical properties and mixture compositions. kinematic viscosity, viscosity gravity constant and paraffin (p), naphthenes (n) and aromatics (a) (pna) analysis are used to predict the composition of lubricants oil. kinematic viscosity gives good behaviors and the oxidation stability for each lubricant oils. pna analysis predicted fractions of paraffin (xp), naphthenes (xn), and aromatics (xa) for each one give us a good value for sample 3 (15w40) leads to suitable classification for this type multi-grade oils by kinematic viscosity keywords: pna analysis, vgc, kinematic viscosity, lubricating oil received on 28/11/2018, accepted on 25/02/2019, published on 30/09/1029 https://doi.org/10.31699/ijcpe.2019.3.3 1introduction the lubricating oil is one of important industries and it is one of the applications of petroleum refining engineering which is produced from oil refining operations that have base oil because the feedstock is the reduced crude oil ‎[1]. crude oil compositions can be classified into hydrocarbons, paraffin, naphtha, and aromatics which are related to the classification of lubricating oils. molecular types in the oils depend on the nature of the oils used and have an effect on the properties of the lubricating oils. the most important characteristics that determine the quality of the lubricant oil are the physical and chemical properties (density, viscosity, viscosity index, etc.) and the effect of temperatures change on the viscosity explain the ability to use oils in engines. density or specific gravity used to characterizing undefined lubricants because it’s correlated with hydrocarbon composition (chemical composition) ‎[2]. the basic functions of lube oils are to remove heat, reduce friction and prevent corrosion; the oils must provide these functions under operating conditions at temperatures changing. there are a few methods available in the literature used to predict the composition so to predict properties of a mixture composition of oils requires the knowledge of pna composition ‎[3]. cerny, j.and strnad, z.[2001].utilized a modified ip 48 procedure (200 °c, 6hour oxidation cycle) to test the oxidation stability of sae 15w-40 engine oils and several differences in ageing behavior were found. viscosity, amount of pentane insoluble within the test were chosen as the parameters to evaluate of oxidation stability of oils ‎[4]. a. awad, and s. mohammed, [2014]. have studied on the enhancements on the lubricant oil properties at different temperatures to enhance the efficiency of lubricant oil density and the thermal expansion with and without additive poly isobutylene, but didn’t have mentions on the mixture composition ‎[5]. s. zzeyani, m. mikou [2018]. they used viscosity evaluation with other parameters to analysis three of synthetic lubricating by inductively coupled plasma optical emission spectrometry (icp/oes), their investigation gives the formation of polycyclic aromatic hydrocarbons and the additives tend to thicken the lubricating oil ‎[6]. s. zzeyani, m. mikou, j.naja [2017], used the electron paramagnetic resonance (epr) and infrared fourier transform (ftir) to evaluate the rate of degradation of lubricating oil, the results were production of organic compounds from degradation and in the same time gets those ftir techniques effective to evaluate of the lubricating oil ‎[7]. v. mäkelä, p. karhunen, s. siren, s. heikkinen[2013], detect by software designed for mass analysis of quantitative spectra (imatranmr) on signals originating from napthene (cycloalkane) structures present in base oil samples to conduct the analysis of the physicochemical properties of base oils ‎[8] there are a lot off investigation that is depending on physical properties and chemical composition for crude oil products as in the study of abdul-halim a.-k. mohammed [2007], improve the viscosity index for https://doi.org/10.31699/ijcpe.2019.3.3 https://www.sciencedirect.com/science/article/pii/s0301679x17301767?via%3dihub#! a. s. bded and t. h. khlaif / iraqi journal of chemical and petroleum engineering 20,3 (2019) 15 21 61 lubricant oil, explain effect of temperature and solvent on chemical composition and physical properties by using the n-d-m method for carbon distribution and analysis ‎[9]. in the other studies, the characterizations of extract lubricating oil at different conditions to make a comparison between the percent of conversion to reduce the aromatic compounds in that's products, this is done by fatimah kadhim [2018] ‎[10]. ibtehal k. shakir [2015] used two types of co-solvents to decreases undesirable materials in raw lubricating oil to improve the viscosity index at the temperature range from 70 to 110 °c ‎[11]. we can conclude from all of them the chemical composition and analysis for lubricating oil very important before and after used in the market. in order to provide basic function of lubricants oils under changing in the temperatures, the quality and properties of lubricants oils depend mainly on the mixture composition, and characterization parameters that are useful for molecular type in pan analysis, this was aim of study by using (riazi-daubert) methods ‎[3] and all assumption was for three types multi-grades oils. 2characterization parameters and experimental test 2.1. properties of lubricants oils three types of multi-grades oils properties were measured in laboratories of petroleum eng. according to astm tests, as shown in the table 1. table 1. lubrication oils parameters and properties parameters sample 1 sample 2 sample 3 test method sae viscosity grades 20w40 10w40 15w40 ----- sg at 15.6 o c 0.895 0.865 0.851 astm d-1217 color l3.5 astm l 3 astm l3.5 astm astm d-1500 api requirements sl sn sf ----- molecular weight 109.358 101.816 98.545 (pedersen.,1989) ‎[12] kinematic viscosity cst at 25 o c – 78 o c 5.7702–0.513 4.609– 0.545 3.8340458 astm d445 all physical properties and other parameters are estimated as the following: 2.2. tests of density, specific gravity, color, and viscosity density and specific gravity(sg): the concept of density is unit weight to unit volume of a fluid and liquid density for hydrocarbons is usually reported in terms of (sg) or relative density defined as, the ratio of the weight of a unit volume of oil to the weight of the same volume of water at a standard (0.999 g/cm 3 (999 kg/m 3 ) at 60 0 f) ‎[13], both of relative density and api degree used for characterizing unknown oils because they have relation with hydrocarbon composition and, therefore, with the nature of the source oil (astm d-l298, ip 160) ‎[14]. in the present research, the method of pycnometer (astm d-1217/ 941 ) used to determine value of density for three type of lubricant oil and then value of sg that needed in calculation of api , vgc, ri and other parameters. kinematic viscosity: kinematic viscosity used to estimate some of physical properties as well as the composition and quality of lubricant oils. in this research the viscosity of lubricating oil is a measure of its flow characteristics at different temperatures experimentally by using cannon-fenske routine viscometer according to the astm d-445‎[14]. the kinematic viscosity (v), (mm 2 /s) of a newtonian liquid calculated from the mean measured flow time (t) (in seconds) and with viscometer constant (c) (mm 2 /s)/s) using the following equation: v= c*t (1) the constant (c) of the viscometer found to be 0.45868. three types of lubricant oil were tests at different temperatures in two times, the first before oxidation of lubricant oil (normal conditions) and the second after oxidation of lubricant oil as shown in. fig.1. the selection of the correct viscosity for the oil is aimed at a balance between a viscosity high enough to prevent the lubricated surfaces from contacting and low enough to minimize energy losses through excessive heat generation caused by having too viscous lubricant (astm d-2422, bs-4231) ‎[14], because the main objective of lubrication is to provide a film between load-bearing surfaces. fig. 1. instrument description of kinematic viscosity test a. s. bded and t. h. khlaif / iraqi journal of chemical and petroleum engineering 20,3 (2019) 15 21 61 the colorastm d-1500: (astm color scale) this method used for determination of the color of lubrication oils in this research, three glass samples and reference container tubes are used with the af 650 comparator together with two discs of color standards ‎[14]. all tests done with two cases, case1 normal condition for lubricant oil and the case2 lube oil has a boiling range up to 200 o c, (in the case2 lube oil heated to temperature of 200 °c with high airflow for six hours to compare the results), and its physical properties were determined according to standard test methods in astm to find oxidation stability from the following ratio ‎[15]: ( ) ( ) (2) equation (2) leads us to know the oils deterioration by oxidation under specified conditions. 3estimation of viscosity gravity constant (vgc) the parameter viscosity gravity constant (vgc) with other parameters were used in this research to estimate samples of lubricant oil compositions by equation (3) ‎[13]. vgc is defined in terms of kinematic viscosity and specific gravity and determined experimentally. ( ) ( ) (3) where: sg and v38 are specific gravity and kinematic viscosity at 38 o c (100 o f in sus) (saybolt universal seconds). vgc arranged for paraffinic (p) from (0.74 0.75), naphthenic (n) (0.89 0.94), and for aromatics between 0.95 and 1.13 ‎[16], as shown in fig. 2, to predict the composition of three types from lubricant oil in this research with the refractivity intercept (ri) determined from the refractive index(n) at 20 o c and density ( ) of each sample by the equation below: (4) 4pna analysis pna analysis is a method used to predict the quantitative determination of paraffin (p), naphthenes (n) and aromatics (a) (pna) in oil mixture. the nature of lubricant oil content on different amounts of paraffin, naphthenes and aromatics groups, this method used to predict the characterizes and quantifies the components in lubricant oil and classifying it. the method of riazidaubert (pna analysis) adopted by the api committee on the characterization of petroleum fractions and is included in the fourth and subsequent editions of the apitdb ‎[13]. this method used both of (ri) and (vgc) to develop a predictive the composition of viscous petroleum fractions as shown in fig.2 indicates the value of ri and vgc are the most suitable parameters to identify hydrocarbon type. [3] fig. 2. characterization factors for viscous of oil fractions ‎[3] pna analysis provides a good knowledge of molecular type of lubricant oil mixture constituents, the first equation is known from the material balance: xp + xn + xa = 1 (5) based on the values of ri and vgc that determine from equation (3) and (4) for all type of lubricant oil, average values of these parameters were determined for the groups of paraffins, naphthenes, and aromatics by applying the following equations for estimation of the pna composition in lubricant oil for heavy fractions at 37.8 o c (100 o f) [3]: xp = a+ b ri + c vgc xn = d + e ri+ f vgc (6) xa = g +h ri+ i vgc xp, xn, and xa calculated from the above relations may represent volume, mole, or weight fractions and a, b, c, d, e, f, g, h, and i are the constants varying with molecular weight range as given in table 2 ‎[17]. the information available for three types of lubricant oils with experimental values are used as input parameters to predict pna composition for each other as shown in discussion. table 2. constants equation (6) ‎[17] constant light fraction heavy fractions constant light fraction heavy fractions a -13.359 2.5737 f 0.81517 1.96312 b +14.4591 1.0133 g -9.6235 -4.0377 c -1.41344 -3.573 h 8.8739 2.6568 d +23.9825 2.464 i 0.59827 1.60988 e -23.333 -3.6701 5results and discussion 5.1. effect of temperature on kinematic viscosity: values of kinematic viscosity of lubricant oil are usually measured and reported at different temperatures also it's decreased with temperatures increasing. fig. 3 illustrates the variation of kinematic viscosity (cst) of three sample from lubricant oils with different temperatures ( o c) at two cases. a. s. bded and t. h. khlaif / iraqi journal of chemical and petroleum engineering 20,3 (2019) 15 21 61 first case (case 1) shows in (a) we can see from the fig. there is different value of kinematic viscosity for each sample under normal conditional and that is clear in the first reading for sample 1 at temperature 27 o c needed efflux time 12.58 seconds as fluid flows from start to stop marks in the viscometer, but the sample 2 was needed 10.05 seconds to measured its kinematic viscosity and 8.36 seconds for sample 3. so the time taken for gravity flow of samples through a restriction is proportional to the kinematic viscosity. after rising in the temperature the kinematic viscosity decreases with an increase in temperature as shown in fig. 3 (a). in the second case (case 2) the lubricant oil was heated up to 200 o c to study of viscosity with change in temperatures and its behavior as shown in fig. 3 (b), the kinematic viscosity decreases with efflux time less than case 1 at same temperature and the comparison for each sample with two cases are shown in fig. 4fig. 6. (a) (b) fig. 3. variation of kinematic viscosity of lubricant oils with temperature o c fig. 4 explain the sample 1 has kinematic viscosity different in both cases but there is a simple converges at 40 o c needed times flow between (6.05 4.55) seconds, in this concept the sample 1 have low viscosity index and extracted from naphthenic oil as shown in table (4) and depended on equation (2) the oxidation stability equal to 0.973 are not critical. fig. 5 illustrate behavior the sample 2 between change in temperature and kinematic viscosity , we can see at 39 o c in both cases have same kinematic viscosity with efflux time between (2.889 2.536) seconds that means the sample2 remain in a relatively unchanged condition with higher temperature and have oxidation stability equal to 0.877 less than sample1. fig. 6 the sample 3 has very converges in kinematic viscosity with both cases at efflux time between (1.44 1.45) seconds in 45 o c and remain relatively unchanged condition with higher temperature and has oxidation stability equal to 1.02. from all above is the basic functions of lubricants should possess and maintain proper viscosity, flow as a liquid at the operating temperature and have good oxidation stability. fig. 4. comparison of kinematic viscosity of lubricant oil (sample1) with two cases with change in temperature o c fig. 5. comparison of kinematic viscosity of lubricant oil (sample2) with two cases with change in temperature o c a. s. bded and t. h. khlaif / iraqi journal of chemical and petroleum engineering 20,3 (2019) 15 21 61 fig. 6. comparison of kinematic viscosity of lubricant oil (sample3) with two cases with change in temperature o c 5.2. prediction of pna composition pna analysis used to predict of lubricants oils compositions by analysis some of depended characterization (vgc, ri, sg), table 3 and table 4 show value and characterization parameters for three samples. table 3 predicts value of vgc and ri from equations (3) and (4) compared with fig. 3, it is clear vgc evaluated have little value for paraffinic oil, while inversely value for vgc in naphthenic oils. the sample 1 has high value of vgc in type naphthenic and low value in paraffinic but in sample 2 has medium value in both naphthenic and aromatics type. the aromatics are undesirable because it have effect on the oils properties, that seen in sample 3 it was divided value of vgc between high value in naphthenic type and the remained have medium values in both of aromatics and paraffinic type as shown in fig. 7 to explain the variation of composition of lubricant oil types with pna analysis and show us that ri and vgc are the most suitable parameters to identify hydrocarbon type and that leads to applied both of equations (5) and (6) to obtain fractions of paraffins (xp), naphthenes (xn), and aromatics (xa). as in table 4 and high values for fraction of naphthenes (xn) equals to 0.699133197, 0.4291149, and 0.5167164 for sample 1 (20w40), sample 2 (10w40) and sample 3 (15w40) . pna analysis gives us a good value for sample 3 (15w40) leads to suitable classification for this type multi-grade oils by viscosity or kinematic viscosity. table 3. characterization parameters for samples types analysis hydrocarbon type sample 1 (20w40) sample 2 (10w40) sample 3 (15w40) vgc ri sg vgc ri sg vgc ri sg paraffins few few few few few few few few few naphthenes high high medium high few medium high high medium aromatics medium few few medium medium few medium few few table 4. values of pna analysis for types of lubricant oils sample type paraffins (xp) naphthenes (xn) aromatics (xa) sample 1 (20w40) 0.026026213 0.699133197 0.27484059 sample 2 (10w40) 0.26023 0.4291149 0.31065543 sample 3 (15w40) 0.21233 0.5167164 0.270953832 fig. 7. variation of composition for lubricant oil types with pna analysis a. s. bded and t. h. khlaif / iraqi journal of chemical and petroleum engineering 20,3 (2019) 15 21 02 6conclusions  kinematic viscosity measured at different temperatures (25 o c – 78 o c) at two conditions to explain oxidation stability for sample 1 (20w40), sample 2 (10w40) and sample 3 (15w40) equal to 0.973, 0.877, and 1.02 respectively oxidation stability, leads to the basic functions of lubricants oils should maintain suitable viscosity at the operating temperature with a good oxidation stability.  pna analysis gives a clear value to three groups for each sample and high values for fraction of naphthenes (xn) equals to 0.699133197, 0.4291149, and 0.5167164 for sample 1 (20w40), sample 2 (10w40) and sample 3 (15w40) respectively, this method leads to classification of multi-grade oils by kinematic viscosity depended on the original hydrocarbons composition in the lubricants oils. references [1] shreve, “chemical process industries”, 4th. edition mc.graw hill book company inc.1997. [2] ram prasad, “petroleum refining technology”, first edition, delhi, 2007 [3] m. r. riazi., “characterization and properties of petroleum fractions”, 1 st edition, 2005 (astm manual series: mnl50) [4] cerny, j., strnad, z., sebor, g. composition and oxidation stability of sae 15w-40 engine oils. tribol. int. 2001, 34, 127–134. [5] ahmed n. awad, shahad s. mohammed, a study of enhancement of the properties of lubricant oil, american journal of chemistry, 2014, 4(1): 68-72 [6] s. zzeyani , m. mikou, j. naja, “physicochemical characterization of the synthetic lubricating oils degradation under the effect of vehicle engine operation”, eurasian journal of analytical chemistry, 2018, 13(4), em3 [7] s. zzeyani, m. mikou, j.naja, a.elachhab.”spectroscopic analysis of synthetic lubricating oil”, tribology international, vol114, 2017, p 27-32 [8] v. mäkelä, p. karhunen, s. siren, s. heikkinen.” automating the nmr analysis of base oils: finding napthene signals” .fuel,vol111, 2013, p 543-554. [9] abdul-halim a.-k. mohammed, hussain k. hussain, and rafal j. sadiq” the effect of solvent extraction of light lubricating oil on viscosity index and chemical composition” iraqi journal of chemical and petroleum engineering, vol.8 no.4 (december 2007) 1-12 [10] fatimah k. idan , saleem m. obyed.” treatment of waste extract lubricating oil by thermal cracking process to produce light fractions” iraqi journal of chemical and petroleum engineering, vol.19 no.4 december 201813 – 19 [11] ibtehal k. shakir , muslim a. qasim,” extraction of aromatic hydrocarbons from lube oil using different co-solvent” iraqi journal of chemical and petroleum engineering,vol.16 no.1 (march 2015) 79 90. [12] daubert, t. e. and danner, r. e, eds., api technical data book petroleum refining, 6th ed., american petroleum institute (api), washington, dc,1997. [13] uttam ray chaudhuri, “fundamentals of petroleum and petrochemical engineering”, 2011 by taylor and francis group. [14] james g. speight, handbook of “petroleum product analysis”, 2002 by john wiley & sons, [15] nelson, w. l., “petroleum refinery engineering”, 4th ed., mcgraw -hill book co., new york, 1958. [16] riazi, m. r. and daubert, t. e., "prediction of the composition of petroleum fractions," industrial and engineering chemistry, process design and development, vol. 19, no. 2, 1980, 289-294. [17] m. a. fahim, taher a. alsahhaf, and a. elkilani, fundamentals of petroleum refining, first edition 2010, elsevier b.v. https://www.sciencedirect.com/science/article/pii/s0301679x0000150x https://www.sciencedirect.com/science/article/pii/s0301679x0000150x https://www.sciencedirect.com/science/article/pii/s0301679x0000150x http://article.sapub.org/10.5923.j.chemistry.20140401.11.html#sec1 http://article.sapub.org/10.5923.j.chemistry.20140401.11.html#sec1 http://article.sapub.org/10.5923.j.chemistry.20140401.11.html#sec1 https://www.researchgate.net/profile/soukayna_zzeyani/publication/324962009_physicochemical_characterization_of_the_synthetic_lubricating_oils_degradation_under_the_effect_of_vehicle_engine_operation/links/5b088bae0f7e9b1ed7f564ec/physicochemical-characterization-of-the-synthetic-lubricating-oils-degradation-under-the-effect-of-vehicle-engine-operation.pdf https://www.researchgate.net/profile/soukayna_zzeyani/publication/324962009_physicochemical_characterization_of_the_synthetic_lubricating_oils_degradation_under_the_effect_of_vehicle_engine_operation/links/5b088bae0f7e9b1ed7f564ec/physicochemical-characterization-of-the-synthetic-lubricating-oils-degradation-under-the-effect-of-vehicle-engine-operation.pdf https://www.researchgate.net/profile/soukayna_zzeyani/publication/324962009_physicochemical_characterization_of_the_synthetic_lubricating_oils_degradation_under_the_effect_of_vehicle_engine_operation/links/5b088bae0f7e9b1ed7f564ec/physicochemical-characterization-of-the-synthetic-lubricating-oils-degradation-under-the-effect-of-vehicle-engine-operation.pdf https://www.researchgate.net/profile/soukayna_zzeyani/publication/324962009_physicochemical_characterization_of_the_synthetic_lubricating_oils_degradation_under_the_effect_of_vehicle_engine_operation/links/5b088bae0f7e9b1ed7f564ec/physicochemical-characterization-of-the-synthetic-lubricating-oils-degradation-under-the-effect-of-vehicle-engine-operation.pdf https://www.researchgate.net/profile/soukayna_zzeyani/publication/324962009_physicochemical_characterization_of_the_synthetic_lubricating_oils_degradation_under_the_effect_of_vehicle_engine_operation/links/5b088bae0f7e9b1ed7f564ec/physicochemical-characterization-of-the-synthetic-lubricating-oils-degradation-under-the-effect-of-vehicle-engine-operation.pdf https://www.sciencedirect.com/science/article/pii/s0301679x17301767?via%3dihub https://www.sciencedirect.com/science/article/pii/s0301679x17301767?via%3dihub https://www.sciencedirect.com/science/article/pii/s0301679x17301767?via%3dihub https://www.sciencedirect.com/science/article/pii/s0301679x17301767?via%3dihub https://doi.org/10.1016/j.fuel.2013.04.020 https://doi.org/10.1016/j.fuel.2013.04.020 https://doi.org/10.1016/j.fuel.2013.04.020 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/490/496 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/490/496 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/490/496 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/490/496 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/490/496 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/490/496 https://doi.org/10.31699/ijcpe.2018.4.2 https://doi.org/10.31699/ijcpe.2018.4.2 https://doi.org/10.31699/ijcpe.2018.4.2 https://doi.org/10.31699/ijcpe.2018.4.2 https://doi.org/10.31699/ijcpe.2018.4.2 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/247/243 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/247/243 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/247/243 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/247/243 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/247/243 https://pubs.acs.org/doi/pdf/10.1021/i260074a016 https://pubs.acs.org/doi/pdf/10.1021/i260074a016 https://pubs.acs.org/doi/pdf/10.1021/i260074a016 https://pubs.acs.org/doi/pdf/10.1021/i260074a016 https://books.google.iq/books?hl=en&lr=&id=ucfsv1mmfhic&oi=fnd&pg=pp1&dq=%5b17%5d%09m.+a.+fahim,+taher+a.+alsahhaf,+and+a.+elkilani,+fundamentals+of+petroleum+refining,+first+edition+2010,+elsevier+b.v.+&ots=e19vfzsjqw&sig=7lzuwoihiun9f8zexll7q7cpots&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=ucfsv1mmfhic&oi=fnd&pg=pp1&dq=%5b17%5d%09m.+a.+fahim,+taher+a.+alsahhaf,+and+a.+elkilani,+fundamentals+of+petroleum+refining,+first+edition+2010,+elsevier+b.v.+&ots=e19vfzsjqw&sig=7lzuwoihiun9f8zexll7q7cpots&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=ucfsv1mmfhic&oi=fnd&pg=pp1&dq=%5b17%5d%09m.+a.+fahim,+taher+a.+alsahhaf,+and+a.+elkilani,+fundamentals+of+petroleum+refining,+first+edition+2010,+elsevier+b.v.+&ots=e19vfzsjqw&sig=7lzuwoihiun9f8zexll7q7cpots&redir_esc=y#v=onepage&q&f=false a. s. bded and t. h. khlaif / iraqi journal of chemical and petroleum engineering 20,3 (2019) 15 21 06 ( النواع مختلفة من زيوت التزييت pnaتقييم خصائص وتحليل) اسعد سالم و تحسين حميد قسم هندسة النفط, جامعة كربالء, العراق الخالصة في هذا .دراسة الخصائص الفيزياوية لزيوت التزييت وتصنيفها تعتبر مهمة لمعرفة نوعية الزيوت وجودتها البحث تم دراسة المعامالت االساسية التي تدخل في تصنيف الزيوت. استخدمت ثالث انواع من الزيوت التزييت الدرجة حيث تم حساب الخصائص الفيزياوية لها ومكونات المزيج بدرجات حرارة متغيرة تتراوح -ذات نوع متعددة اتيكية وثابت المزوجة وطريقة تحميل المكونات كل .تم استخدام كل من المزوجة الكينم oc52 – oc87بين لتنبأ المكونات لزيوت التزييت. المزوجة الكينماتيكية اعطت سموك ( pna)البرافينات والنفثينات والعطريات من (xp)اعطت نسب كل من المكونات البرافينات (pna)جيد مع ثابت استقرارية لكل زيت. طريقة التحميل وكذلك استنتجت الطريقة قيم الداخمة في تركيب كل نوع من الزيوت المستخدمة (xa)والعطريات (xn)والنفثينات الدرجات بواسطة –وهذا مؤشرمناسب لتصنيف الزيوت متعددة (15w40)جيدة لمنوع الثالث من الزيوت الكينماتيكيةالمزوجة , اللسوجة الحركية, زيوت التشحيمpnaالكلمات الدالة: تحليل the use of direct solar energy in absorption refrigeration employing nh3 – h2o system 13 iraqi journal of chemical and petroleum engineering vol.11 no.4 (december 2010) 13-21 issn: 12010-4884 the use of direct solar energy in absorption refregeration employing nh3 – h2o system prof. dr. adel a. al-hemiri and ahmed deaa nasiaf chemical engineering department, college of engineering, university of baghdad, iraq ______________________________________________________________________________________ abstract this work was conducted to study the coefficient of performance for solar absorption refrigeration by using direct solar energy using aqueous ammonia 0.45 mass fraction (ammonia – water).the experiments were carried out in solar absorption system .the system consisted of solar collector generator (0.25 m × 0.25 m × 0.04m) and condenser cooled by a water bath followed by liquid receiver and evaporator. the results showed that the maximum generator temperature was (92° 97°) during june 2009, and the minimum evaporator temperature was (5°c 10°c) for aqua ammonia system.. it was, also, found that the coefficient of performance, cooling ratio and amount of cooling obtainable increased with increasing maximum generator temperature and pressure. while the minimum evaporator temperature and concentration decreased with increasing maximum generator temperature and pressure. the coefficient of performance was (0.1096 0.2396). keyword: solar energy, absorption refrigeration introduction in the developing countries there is a growing interest in refrigeration for food preservation. especially in rural areas, simple solar refrigerators working independently, i.e. not being provided with electrical energy, would be very valuable. mechanical refrigerators powered by solar cells are available, but are too expensive [1]. in iraq the climate features high temperature in summer season and high solar radiation. the director beam solar iraqi journal of chemical and petroleum engineering university of baghdad college of engineering the use of direct solar energy in absorption refregeration employing nh3 – h2o system 14 ijcpe vol.11 no.4 (september 2010) radiation in north of iraq is (5 – 6 kw.hr/m 2 ) and in the middle and south is (6 – 6.5 kw.hr/m 2 ) and (6.5– 7 kw.hr/m 2 ) respectively [1].these two conditions helping to use solar energy for:  solar heating  solar refrigeration and air conditioning  solar desalination  solar food drying  solar photovoltaic  solar furnaces a solar refrigeration system consists of two components, a solar power units and a refrigeration unit. the solar power unit is based on either of two basic concepts, i.e. flat plate collectors or focusing collectors [2]. flat plate collectors are flat blackened surfaces to absorb direct and diffuse solar radiation. transparent cover and back insulation may be provided to reduce or control heat loss from the plate. on the plate, absorbed solar energy is converted to a desired form of energy, usually heat, and means are provided to remove that energy, usually as heated water or air. flat plate collectors are generally suitable for operation in a fixed orientation. the refrigeration unit can be either a continuous or an intermittent absorption system. the intermittent absorption refrigeration is preferred .the intermittent refrigeration cycle has two major operations, regeneration and refrigeration .regeneration is the process of heating the refrigerant and absorbent fluid to drive off the refrigeration vapour and condense the vapour in a separate container.refrigeration takes place when the liquid refrigerant vaporizes; producing a cooling effect around the evaporator .the refrigerant is reabsorbed by the absorbent [2]. the first absorption refrigeration system was developed by ferdinand carre in 1860 [3]. this was the first heat operated absorption system and consists of an evaporator, condenser, generator, pump, and absorber. this unit was designed to operate with ammonia as the refrigerant and water as the absorbent. in the university of wisconsin, williams [4] built a small food cooler in 1957 intended for use in underdeveloped rural areas. ammoniawater and r-21-glycol ether were used as working solutions. this study showed that refrigeration can be achieved by the use of intermittent absorption refrigeration cycles. although performance is limited by the characteristics of the intermittent cycle, the simplicity of the system accounts for the low temperature obtained in the evaporator. finally, the study showed that ammonia-water has a superior performance over r-21-glycol ether in an intermittent refrigeration system . chinnappa (1962) built a simple intermittent refrigerator operated with a flat-plate collector. an ammonia-water solution was used as the working fluid. while it has been generally expected that the flat-plate collector would be more suitable for the lower temperature of generation required in air conditioning, tests in the investigation by chtnnappa (1962) indicated that it is possible to use a flat-plate collector incorporated with the generator to produce refrigeration at a temperature as low as -12°c. it is noted that ice can be produced in this refrigerator at one kg a day per 0.7 m 2 of solar collecting surface. results in this prof. dr. adel a. al-hemiri and ahmed deaa nasiaf 15 ijcpe vol.11 no.4 (september 2010) investigation were not spectacular, but they showed that a simple intermittent refrigerator using a low temperature heat collecting device such as the flat-plate collector can achieve cooling [5]. the first major project on an all solar absorption refrigeration system was undertaken by trombe and foex (1964)[6]. ammonia-water solution is allowed to flow from a cold reservoir through a pipe placed at the focal line of a cylinder-parabolic reflector. heated ammonia-water vaporized in the boiler is subsequently condensed in a cooling coil. the evaporator is a coil surrounding the container used as an ice box. the cylindro-parabolic reflector measured 1.5 m'. in the prototype trials, the daily production of ice was about 6 to 4 kilograms of ice per square meter of collecting area for four-hour heating. the design by trombe and foex is very promising and should be studied further although modifications may be necessary on the solar collector, boiler, and condenser. farber (1970)[7] has built the most successful solar refrigeration system to date. it was a compact solar ice maker using a flat-plate collector as the energy source. it was reported that an average of about 42,200 kj of solar energy was collected by the collector per day and ice produced was about 18.1 kilograms. this gave an overall coefficient of performance of about 0.1 and 12.5 kilograms of ice per m 2 of collector surface per day. swartman and swaminathan (1971) [8] built a simple, intermittent refrigeration system incorporating the generator-absorber with a 1.4 m 2 flatplate collector. ammonia water solutions of concentration varying from 58 to 70 percent were tested. tests were relatively successful; evaporator temperatures were as low as -12°c, but due to poor absorption, the evaporation rate of ammonia in the evaporator was low. staicovici [9] made an intermittent single-stage h2o-nh3 solar absorption system of 46 mj/cycle (1986). solar collectors heat the generator. installation details and experimental results were presented. the system coefficient of performance (cop)system varied between 0.152 and 0.09 in the period of may– september. solar radiation availability and the theoretical (cop), also applicable to the trombe-foex system, were assessed. reference was made to evacuated solar collectors with selective surfaces. actual (cop) system values of 0.25–0.30 can be achieved at generation and condensation temperatures of 80°c and 24.3°c respectively. in 1993 sierra, best and holland [10] made a laboratory mordent of absorption refrigeration. using ammonia water solution at 52 % concentration by weight and the total weigh is 38 kg. this system was operated intermittently using this heat source .a heat source at temperature no higher than 80 °c was used to simulate the heat input to an absorption refrigeration from solar pond .in this system the temperatures of generator was as high as 73 °c and evaporator temperatures as low as -2 °c . tap water was used to remove the heat generated from the condensation of the ammonia vapor and the absorption of the refrigerant in the water. the temperature of the tap water was near the ambient laboratory temperature of 28 °c. the cop for this unit working under such condition was in the range 0.24 to 0.28 . the use of direct solar energy in absorption refregeration employing nh3 – h2o system 16 ijcpe vol.11 no.4 (september 2010) in 2000 hammad and habali [11] made a steel sheet cabinet of 0.6 m x 0.3 m face area and 0.5 m depth. the cabinet was intended to store vaccine in the remote desert area, away from the electrical national grid. a solar energy powered absorption refrigeration cycle using aqua ammonia solution was designed to keep this cabinet in the range of required temperatures. the ambient temperatures reached about 45 °c in august. a computer simulation procedure was developed to study the performance and characteristics of the cooling cycle. the simulation included matlab computer programs for calculation the absorption cycle. in this system using a cylindrical solar concentrator extended the daily operating time to about 7 h and increased the output temperature up to 200 °c and the range of the cop was between 0.5 to 0.65 .while the temperature which gives optimum condition (of cop =0.65 )was 120 °c. for this study a solar absorption refrigeration unit was constructed. the fig. 1 schematic diagram of the equipment used working fluids employed was aqueous ammonia (25wt% nh3 – h2o) .the system was operated during the months of june and july (2009) for a period of 8 hours per day (8 am to 4 pm). prof. dr. adel a. al-hemiri and ahmed deaa nasiaf 17 ijcpe vol.11 no.4 (september 2010) assessment of the system is by determining the following relevant parameters:  cooling obtainable  cooling ratio  solar coefficient of performance (c.o.p). experimental work apparatus the systems consist of generator. it was fabricated from 2 mm thick stainless plate (316) painted black to improve on it’s solar radiation absorbing capabilities. the section is rectangular and the dimensions are (25 cm x 25cm x 5 cm) and at 20° inclined angle. the volume is 2.5 liters. steel was used because other nonferrous material like copper and brass are attacked by ammonia. all side of the generator were insulated except the solar side. the second part of the system is the condenser which consists of a small coil (1cm diameter and 20 cm length 0.2 cm thickness) was immersed in cold water bath after that the receiver follows the condenser .the benefit of receiver is to collect liquid condensate outside of the condenser. and the evaporator is stainless steel pipe 1cm diameter and 10 cm length 0.2 cm thickness (fig 1). experimental procedure during the regeneration, valve a is open and valve b is closed(fig. 1), and the strong solution in the generator being heated by the flat-plate collector producing vapor at a high pressure, the weak solution returns from the top to the bottom of collector. the vapor in the top header collector is mainly ammonia because water has a much lower volatility than ammonia. the ammonia vapor passes into the condenser which is immersed in a cold water bath to keep it cool, the pressure is uniform throughout the system. when heating stops at 14:30 pm (maximum generators temperature and pressure) valve a is closed and the vapor pressure in the generator drops. the concentration in the generator is now less than it was before regeneration, after that valve b was opened. the condenser now functions as the evaporator. ammonia vaporizes due to the pressure difference between the generator and evaporator. the vaporization of ammonia absorbs heat from the surroundings of the evaporator, thus producing the refrigeration effect. ammonia vapor from the evaporator passes through the pipe and taken to the bottom of the collector so that the incoming vapor bubbles through the solution thus facilitating absorption in it. refrigeration continues until all the liquid ammonia in the evaporator has vaporized. a full cycle of operation has now been completed. the temperature and pressure of the evaporator and absorber were recorded every 5 minutes . while the ambient, solution and generator temperature and the generator pressure were recorded at 30 minutes intervals. results of experiments are given in table (1) in the appendix. discussions variation of temperatures and pressure with time in regeneration cycle the use of direct solar energy in absorption refregeration employing nh3 – h2o system 18 ijcpe vol.11 no.4 (september 2010) fig. 2 shows the variation of generator (tg), solution (tso), ambient (tam) temperature with time (t). the average mean generator temperature (tgavr) was between (61.5 to 66.7 °c).the maximum generator temperature (tgmax) for five runs was between (92 to 97 °c) this maximum temperature recorded at 02:30 pm because the sun at this time is vertically to collector . in the same figure the pressure variation with time it also shown .initial pressure was for five runs (average) 2.4 bar and reached to maximum pressure(pg) at 02:30 pm .the maximum pressures was about 12.9 bar for generation cycle, as a result of heating the generator and closing the exiting valve of the generator. and return to initial value after complete absorption cycle. fig.2 variation of generator, ambient and solution temperature and generator pressure with time (nh3h2o) variation of temperatures and pressure with time in refrigeration cycle fig.3 shows the variation between evaporator (te), absorber (tab) temperature and evaporator (pe), absorber (pab) pressure with refrigeration time. in this figures the evaporator temperature was about (30 to 35 °c) and pressure (10.4 to 10.7 bar). at this stage the temperature of surrounding more than evaporator temperature causing transfer of heat from surrounding to evaporator. the minimum evaporator temperature was (5 to 10 °c) for five runs. at these temperatures liquid ammonia was evaporated and evaporator pressure dropping to initial pressure (2.4 to 2.7 bar). liquid ammonia was evaporated at ( 5 to 10 °c) and enter to absorber .the condition was (25 °c) and (1.7 bar) the vapor of ammonia absorbed in absorber the temperature of absorber increases to (32 to 34 °c) because the absorption is exothermic. the pressure in absorber at the end of refrigeration cycle equal to evaporator pressure. fig.3 variation of temperature and pressure in the evaporator and absorber with time (nh3-h2o) prof. dr. adel a. al-hemiri and ahmed deaa nasiaf 19 ijcpe vol.11 no.4 (september 2010) fig.4 effect of maximum generator temperature on c.o.p (nh3-h2o) effect of maximum temperature on c.o.p figs.4 and 5 shows the effect of maximum temperature and pressure on c.o.p for five runs it was found the c.o.p increases with maximum generation temperature and pressure .this is because the quantity of nh3 evaporated increases with increasing maximum generation temperature. fig.5 effect of maximum generator pressure on c.o.p (nh3-h2o) effect of maximum generator temperature and pressure on evaporator temperature fig. 6 shows the effect of maximum generator temperature and pressure on evaporator temperature. the minimum evaporator temperature (temin) decreases with increasing maximum generator temperature and pressure. fig.6 effect of maximum generator temperature on evaporator temperature (nh3-h2o) conclusions the following conclusions could be drawn from the present research during the months of june and july (2009), 1. the maximum generator temperature was found to be 97 °c. 2. the range of c.o.p for the aqueous ammonia system was (0.1096 0.2396). 3. the range of minimum evaporator temperature was (5°c 10°c). 4. cooling ratio and cooling obtainable increases with increasing maximum generator temperature and pressure. 5. the final concentration decreases with increasing maximum generator temperature and pressure. the use of direct solar energy in absorption refregeration employing nh3 – h2o system 20 ijcpe vol.11 no.4 (september 2010) nomenclature c.o.p coefficient of performance pab absorber pressure pe evaporator pressure pg generator pressure t time tab absorber temperature tam ambient temperature te evaporator temperature temin minimum evaporator temperature tg generator temperature tgavr average generator temperature tgmax maximum generator temperature tgmean mean generator temperature tso solution temperature references [1]abdul hai, s and abdul jabbar, k(1984)"iraq’s national paper,solar in iraq",symposium using solar energy in heating and cooling, organization of arab petroleum exporting and solar energy research center in the scientific research council,baghdad. [2]sorensen b (2004) “renewable energy " ,third edition by elsevier science. [3]enibe s. o. (1997) “solar refrigeration for rural applications", elsevier science, renewable energy, vol. 12, no. 2, pages 157-167s. [4]williams, d. a., chung, r., lof, g. o. g., fester, d. a., and duffle, j. a. (1957), "intermittent absorption cooling systems with solar regeneration", paper no. 57-a-60, a.s.m.e. [5]chinnappa, j. c. v., (1962), " performance of an intermittent refrigerator operated by a flat-plate collector ”solar energy vol. 6, pages 143-150. [6]trombe, f., and foex, m., (1964)," economic balance sheet of ice manufacture with an absorption machine utilizing the sun as the heat source " new courses of energy, vol. 4, u.n. publication sales no. 63.1.38, pages 56-59. [7]farber, e. a., (1970)," design and performance of a compact solar refrigeration system "paper no. 6/58, 1970, international solar energy society conference, melbourne, australia. [8]swartman, r. k., and swaminathan, c., (1971)," solar powered refrigerator, mechanical engineering" june 1971, vol. 6, page. 22-24. [9]staicovici m. d.,(1986)" an autonomous solar ammonia-water refrigeration system", solar energy, volume 36, issue 2, 1986, pages 115124. [10]kouremenos d. a, antonopoulos k. a and rogdakis. e. (1990)," performance of a solar driven compound (nh3/h2020/libr) sorption refrigeration system in [11] athens",solar & wind technology vol. 7, no. 6, pages 685-597. prof. dr. adel a. al-hemiri and ahmed deaa nasiaf 21 ijcpe vol.11 no.4 (september 2010) [12]hammad m, habali s. (2000)," design and performance study of a solar energy powered vaccine cabinet",bywww.elsevier.com/locate/ap thermeng,applied thermal engineering 20 pages 1785-1798. [13]nasiaf, a.d., (2010) "the use of direct solar energy in absorption refrigeration", msc thesis, chem. eng. dept., baghdad university. appendix table 1 summary of experimental results for aqueous ammonia system[13]. date june 2009 day 3 9 11 14 22 regeneration units initial mass of solution gm 1000 1000 1000 1000 1000 initial mass concentration _ 0.45 0.45 0.45 0.45 0.45 initial solution temp °c 35 34 35 34 33 max solution temp °c 90 96 93 94 91 max generator pressure bar 12.5 12.9 12.7 12.8 12.6 incident solar radiation kj 532 532 532 532 532 heat to collector plate kj 148.4 241.58 194.75 222.71 176.62 mean generator temp °c 62.5 65.5 63 64 62 condenser temp °c 30 30 30 30 30 final concentration _ 0.42 0.38 0.41 0.39 0.4 refrigeration nh3 evaporated gm 51.7 113 88.3 98.3 67.8 min evaporator temp °c 10 5 8 6 8 cooling obtainable kj 58.32 127.47 94.95 111.35 77.59 cooling ratio _ 0.3929 0.5275 0.4875 0.4999 0.4393 solar c.o.p _ 0.1096 0.2396 0.1784 0.2093 0.1458 الترسيب اللاكهربائي للنحاس على لدائن abs البلاستيكية المجلة العراقية للهندسة الكمياوية وهندسة النفط 4-1)2009حزيران )2 العدد 10المجلد issn: 1997-4884 تحضير ودراسة طيفية وكيميائية للعامل المساعد cuo-zno-al2o3 , cuo-zno-al2o3 x-ray diffraction (xrd) flame atomic absorption (faa)bet braunauer, emmett and teller gas chromatography (gc) ,2 (co-wet mixing) (coprecipitation)(impregnation) (9,8,7,6,5,3) (spraying) 10) (11) cuo-znoal2o3 university of baghdad college of engineering iraqi journal of chemical and petroleum engineering cuo-zno-al2o3تحضير ودراسة طيفية وكيًيبئية نهعبيم انًسبعد chemicals zn(no3)2.6h2o .fluka ag. chemicals cu(no3)2.3h2o merck al(no3)3 .9h2o merck nahco3b.d.h ch3ch2oh .fluka hcl merck apparatus radiationpw 1410/20 cukαphilips asap 2000, v1. o3america micromeretics a-a-680 atomic absorption spectroscopy shimadzue quantachrome autoscan mercury porosimetry data report version 1.34 america. pye unicom series 304 chromatogaphyphilips england gallenkamp h-meterpu.k.kink england gallenkamp mettler preparation method ˚ ˚ ˚ chemical analysis al zn cu al2o3znocuo total oxides (xrd)x-ray diffraction spectroscopy θ d-value˚a(i/io) صبنح هبدي كبظى و عهي عبد انصبحب ,هيف عكبلرجهيم cuo-zno-al2o3 θdcuo-zno-al2o3 θda˚θda˚ i/i˚ 31.8 2.811531.72.81zno 71% 34.62.5934.52.60zno 56% 35.62.5135.52.52cuo 100% 36.32.4736.12.47zno 100% 37.62.3937.52.39γ– al2o3 80% 38.82.3338.72.32cuo 96% 44.52.0345.81.98γ– al2o3 80% 47.71.9047.61.91zno 29% 56.31.6356.61.62zno 40% 61.41.5161.01.52γ– al2o3 30% 62.61.48631.47zno 40% 65.61.4265.91.41cuo 12% 66.31.4067.11.39γ–al2o3100% 67.71.3867.11.39γ– al2o3 100 67.91.3868.11.37cuo 19% 68.91.3668.11.37cuo 19% cuo-zno-al2o3 dnλ= 2d sinθ dinteraction bet al2ocuo-zno cuo-zno-al2o3تحضير ودراسة طيفية وكيًيبئية نهعبيم انًسبعد m 2 /gm cc/gm g/cc cuo-zno-al2o3 66.1264.60.421.54 cuo-zno 20.7652.90.232.26 cuo-zno γγ– al2o3cuo-znoγ local overheating (16,19,3) اننسب انًئوية نحجوو انًسبيبت % يعدل نصف قطر انًسبية a˚ 0.0 27.5 12.18 65 37.11 150 15.57 250 12.42 350 15.82 450 5.23 550 0.24 650 0.18 750 0.14 850 0.11 950 0.51 1500 0.17 2500 0.08 3500 ˚ صبنح هبدي كبظى و عهي عبد انصبحب ,هيف عكبلرجهيم ˚ retention timea b cde ˚ a b˚ c˚d˚ e˚ 2ch3cho ch3cooc2h5 2ch3cho + h2o ch3-c-ch3 + co2 + 2h2 ˚ o cuo-zno-al2o3تحضير ودراسة طيفية وكيًيبئية نهعبيم انًسبعد 1m. bowker " the basic and heterogeneous catalysis", series sponser, published in the united state of america by oxford university, inc., new york, 53, 3 (1998). 2j.t.richardson," principle of catalyst development", plerum press, new york, (1989). 3c.n.satterfield, "chemical engineering",94 (1980). 4g.w.higginson, "chemical engineering", 94,sep.30 (1974). 5g.poncelet, p. grange and p.a.jaccobs,(editors), “preparation of catalysts”, v.3,elesvier science b.v., amsterdam-printed in the netherlands, 486(1983). 6p.herry, "catalytic study of copper based catalysts for steam reforming of methanol" ph.d. thesis, technical university of berlin, germany (2003). 7l.gao, y. tang, q.xue, and y. lu, "energy and fuels", 23, 624 (2009). 8m.komiyama, “design and preparation of impergenated catalysis”, cat.rev.,27,34 (1985). 9d.s.mclver, h.h. tobin and r.t.barth, j. cat., 2, 485(1963). 10-p.b. himel farb, g. w. simmons, k. kiler and r.g.herman, j. cat., 93, 442(1985). 11k. othmer, “copper compared, encyclopedia of chemical technology”, 2nd ed., v. 6, america, 275(1965). 12n. orgine, i. kobal and m.s. acink, j. phys. chem., 101, 7236(1997). 13a.a. dyaltov and v.e. ostrovskii, j. kinet. cat., v.25 ;(1,part2), 129(1984). 14. p.j. whiteside, pye unicom atomic absorption data book, 2nd .ed., cambridge, england, 7(1976). 15. g. vlaic, j.c.j. bart, w. cavigiolo, b. pianzola and s. mobilio, j. cat, 96, 315(1985). 16. s.m. salih "physics of diffraction" baghdad, 60 (1982). 17. c.n. satterfield and n. charles, “heterogeneous catalysis in practice”., new york, mcgraw-hill inc., 106(1980). 18. g.a. el-shobaky, g.a. fagal and a.s. ahmed, ads. sci. and techn. 15 (9) ,77(1998). 19. m. bowker, “ the basic heterogeneous catalysis”, series sponser, published in united state by oxford university press. inc. new york, 53, 3(1998). 20. s. kolboe, j. cat., 3, 193 (1969). 21. k. tanab, t. nakajima, t. yamaguchi, i. matsuzaki and s. mishima, appl. cat., 52, 237 (1989). صبنح هبدي كبظى و عهي عبد انصبحب ,هيف عكبلرجهيم electro-less copper deposition on abs plastic jalil r. e., ali a. s. and salih h. university of baghdad abstract cuo-zno-al2o3 catalyst was prepared in the ratios of 20:30:50 respectively, using the coprecipitation method of cu, zn and al carbonates from their nitrate solutions dissolved in distilled water by adding sodium bicarbonate as precipitant. the catalyst was identified by xrd and quantitatively analysis to determine the percentages of its components using flame atomic absorption technique. also the surface area was measured by bet method. the activity of this prepared catalyst was examined through the oxidation of ethanol to acetaldehyde which was evaluated by gas chromatography. key words: cuo-zno-al2o3 catalyst, in ratio (20:50:30). ijcpe vol.11 no.2 (june 2010) iraqi journal of chemical and petroleum engineering vol.11 no.2 (june2010) 49-54 issn: 1997-4884 study on vanadium recovery from spent catalyst used in the manufacture of sulfuric acid khalid m. mousa and safa k. kouba chemical engineering department/collage of engineering/ university of nahrain abstract spent catalysts for sulfuric acid production have large amount of vanadium and due to environmental authority it is required to reduce the vanadium contain of the spent catalyst. experimental investigation was conducted to study the vanadium recovery from spent catalyst via leaching process using sodium hydroxide to study the effect of process variables (temperatures, sodium hydroxide molarities, leaching time and particle size) on vanadium recovery. the effect of process variables (temperature, particle size,molarities of sodium hydroxide and leaching time) on the percentages of vanadium recovery were investigated and discussed .it was found that the percentage of vanadium recovery increased with increasing temperature up to 100 , increasing sodium hydroxide molarity from 2 to 4m, increasing leaching time, decreasing particle size from mesh 150, 100 and 65. a complete vanadium recovery was achieved at the following conditions: temperature (100˚c), particle size (150 mesh ) molarity of na oh(4 molar) and leaching time(5 h). key words: vanadium, spent catalysts, sulfuric acid _____________________________________________________________________________________________ introduction vanadium is employed for the manufacture of a variety of vanadium compounds. vanadium compounds have been found effective for catalyzing both organic oxidation and reduction. the oxides of vanadium have found many applications as catalysts especially in vaporphase reductions. vanadium pentoxide is the most common commercial form of vanadium. it can be used as a dye and color-fixer, and it's used as a catalyst in the production of sulfuric acid by contact process. catalysts based on vanadium pentoxide are widely used in the conversion of naphthalene to phthalic anhydride. vanadium is also used as catalyst in the process of co₂ removal from the gas mixture in ammonia synthesis west [1]. haoran et al. ,[ 2]; studied recovery of vanadium from clay vanadium mineral using an acid leaching method references and further reading may be available for this article. to view references and further reading you must purchase this article.. a technique is including direct acid leaching. stas et al., [3] studied the recovery of vanadium, nickel and molybdenum from fly ashes produced from heavy oil-fired electrical power station using two stages leaching process which consisted of an alkaline leaching to dissolve vanadium and molybdenum followed by sulfuric acid leaching to recover nickel. lozano, and godínez ,[4 ] studied the solvent extraction of vanadium in sulphate media using primary amine and tertiary amine dissolved in kerosene has been carried out. luis and cury ,[5 ] studied the catalyst leaching in order to reduce its vanadium content so that it can be safely disposed. factorial experimental design was used and the process variables studied were particle size, temperature, acid concentration and agitation intensity. results showed strong dependency between remaining vanadium content and particle size. temperature has shown lesser influence. the latter indicates an intra particle diffusion controlled process. conventional method for recovering vanadium from vanadium containing ores was studied by hansen, [6]. this method included as an initial step the roasting of the vanadium ore with a sodium salt to form roasted products which contain sodium vanadate in solid form. the roasted material was then cooled, crushed, ground and water leached in agitation leach tank in a conventional manner. the solubilized sodium vanadate in solution was recovered from the solids through university of baghdad college of engineering iraqi journal of chemical and petroleum engineering http://en.wikipedia.org/wiki/vanadium(v)_oxide http://en.wikipedia.org/wiki/vanadium(v)_oxide http://en.wikipedia.org/wiki/vanadium(v)_oxide http://en.wikipedia.org/wiki/vanadium(v)_oxide http://en.wikipedia.org/wiki/vanadium(v)_oxide http://www.sciencedirect.com/science?_ob=articleurl&_udi=b82xw-4sjyx8s-3&_user=10&_coverdate=04%2f30%2f2008&_rdoc=1&_fmt=full&_orig=search&_cdi=33041&_sort=d&_docanchor=&view=c&_acct=c000050221&_version=1&_urlversion=0&_userid=10&md5=4ec626f7fc44c138d171479f03f33a26 study on vanadium recovery from spent catalyst used in the manufacture of sulfuric acid ijcpe vol.11 no.2 (june 2010) 50 convential solid-liquid separation such as filtration or counter current decantation. jassim,[7] used a solvent extraction technique as a separation method to separate a vanadium from the leach solution of the ashes of burned fuel oil at electrical power station . tributyl phosphate (tbp) was used as an extracting agent through mixersettler batteries. some parameters, which influenced vanadium extraction, were studied in detail, such as chloride ion concentration and the acidity of the mother solution, in addition to the number of extraction, stripping stage and phase ratios. mousa [8 ] recovered vanadium from scale residues of oil-fired power stations by alkaline leaching method using sodium hydroxide solution . spent catalysts for sulfuric acid production have large amount of vanadium and due to environmental authority it is required to reduce the vanadium contain of the spent catalyst[ khorfan et al. , [9] studied the recovery of vanadium pentoxide from spent sulfuric acid catalysts ,using a three-step process involving acid leaching, oxidation and precipitation. several different acids were used in the leaching, sulfuric acid was used in various concentrations, solid to liquid ratios, stirring times and temperatures. a high solid/liquid ratio in the leaching stage was used to obtain high concentration of vanadium pent oxide and low acid consumption that allowed direct precipitation without the use of extraction by rather expensive organic solvents. sodium carbonate solution of one mole/liter concentration was used in the precipitation stage. sulfuric acid was found to be the best leaching solution. the aim of this work is to study the possibilities of vanadium recovery from spent catalyst used via leaching process using sodium hydroxide due to selectivity of sodium hydroxide to vanadium, and study the factures affecting the leaching process. experimental apparatus experiments were carried out in 1 litter glass reactor, the diameter of glass reactor was 12cm and the height was 10 cm applying on heating mantle with thermostat and a mixer consisted of stainless steel shaft, screwed with four pitched turbine blades impeller , the diameter of impeller was 4 cm. the stirrer rotated by means of an electrical motor coupled to variable resistor to achieve 600 rpm . a schematic diagram of the reactor system is show in fig. 1. fig. 1 a schematic diagram of the reactor system experimental procedure the sample of spent catalyst used in this experimental procedures was obtained from (al-sadra company in the west of baghdad) taken randomly, grinded in laboratory ball mill and sieved by means of laboratory sieve supplied by retsch company to obtain particle size (150 mesh=104 µm ,100 mesh=147 µm and 65 mesh=208 µm ). sodium hydroxide as applet supplied by bdh company (98% ) was used due its selectivity of vanadium. the required (2-4) molar solution of sodium hydroxide was prepared in the experimental tank as fallow. molar = mole / litter of naoh the solution was then heated to the desired temperature (60100ºc) while stirrer at 600 rpm, the rpm was achieved by means of variance coupled with motor .100 gm of spent catalyst with particle size in the rang (mesh 150 to 65) was added to the aqueous solution of sodium hydroxide in each run .the reaction as follow. khalid m. mousa and safa k. kouba ijcpe vol.11 no.2 (june 2010) 51 after the desired time (1-5 hr) the solution was filtered to remove the unreacted vanadium and impurities. a fixed volume of 500 ml was used for all experiments. the block diagram of fig. 2 shows the processes. solid samples of the powder stock, which was used in this work were analyzed for vanadium content and the average percentage was found to be (37 %). this value was used in the calculation of vanadium fraction recovery for each experiment. samples of solutions from all experiments were analyzed for vanadium by means of atomic absorption spectrometry at the analytical laboratory of ibn cina company. fig.2. experimental procedure block diagram results and discussion the effect of temperature on vanadium recovery at different molarity at a given mesh size is shown in figures 3 and 4. observing these figures it can be shown that increasing the temperature will increase the vanadium recovery, the temperature influences the vanadium recovery in number of ways. firstly as the temperature increases the mobility of the molecules will increase due to more energy gain, secondly the effective diffusivity increases with the increase in the temperature. this coincides with the definition of the diffusivity. the main resistances to leaching are: kinetic of the process, intra-particle mass transfer and mass transfer from particle surface to surrounding. the chemical step is usually much more temperaturesensitive than the physical steps. levenspiel,[10]. since the change in temperature affected the fraction recovery one can say that the chemical reaction step is dominate. comparing with the results of luis and cury [5] reveals that the leaching velocity of residual vanadium content influenced by temperature where tested values from 25 to 55˚c,where vanadium recovery was 1310 ppm at( 35 mesh size ,25˚c and 1% sulfuric acid concentration),while 1190 ppm at (35 mesh size ,55˚c and 1% sulfuric acid). khorfan et. al.[9] showed that the temperature affects the vanadium recovery up to 80˚c, above this value no effected was noted. fig. 3 effect of temperature on vanadium fraction recovery at different time for 5molar and 150 mish size study on vanadium recovery from spent catalyst used in the manufacture of sulfuric acid ijcpe vol.11 no.2 (june 2010) 52 fig. 4 effect of temperature on vanadium fraction recovery at different time for 3 molar and 150 mish sizes the effect of particle size on vanadium recovery at different temperature at a given time is shown in fig 5. in this figure it can be seen that the fraction recovery increase as the particle size decrease (increasing mesh size). the particle size influences the fraction recovery in a number of ways. the smaller the size is the greater interfacial area between the solid and liquid, the rate of reaction and the rate of transfer of material are higher. a reduction in particle size usually results in a decrease in the average time of passage of solvent from the surface to the interior of the particle and decrease the average time of passage of solvent from the surface to the interior of the particle and decrease the average time of passage of solute molecules from the dissolving point in the interior of solid particle to the surface of the particle ,rickles,[11] .the effect of naoh molarity on vanadium fraction recovery is shown in fig.6 the figure shows that vanadium recovery increase as the molarity of naoh increases. comparing with result of luis &cury,[5] on which, the results shows that the vanadium recovery does not effected by sulfuric acid concentration, where the vanadium recovery constant at 1110 ppm in spite of changing the concentration from 1% to 10% while the other conditions are constant(65 mish size and 25˚c ). fig 5 effect of temperature on vanadium fraction recovery for 4 molar and 5 h fig. 6: effect of naoh molarity on vanadium fraction recovery for 5 h and 150 mish size. figures 7, 8 and9 shows the plots of fraction of vanadium recovery versus time for different temperatures and a given mesh size and naoh molarity. it is clear from these figures that the best leaching time which lead to maximum recovery of vanadium is greatly dependant on the specific conditions of test i.e particle size, molarity of naoh and temperature of test. examination of figure 6 shows that the maximum fraction recovery was 150 mesh size and 4 molar naoh, where the best leaching time was found to be 5 h at 100˚c. khorfan et al,[9] showed that the leaching was carried out by varying the time of mixing from 10 min to 4 hours while keeping other conditions constant (t = 100 ◦c,solid/liquid = 1/10 g/ml, sulfuric acid 15% v/v). the efficiency was constant after 30min so it is enough to fix the mixing time at one hour for other experiments. khalid m. mousa and safa k. kouba ijcpe vol.11 no.2 (june 2010) 53 fig. 7 effect of time on vanadium fraction recovery for 65 mesh size and 4 molar naoh fig. 8 effect of time on vanadium fraction recovery at different temperatures for 100 mesh size and 4 molar naoh. fig. 9 effect of time on vanadium fraction recovery for 150 mesh size and 4 molar naoh conclusions: 1.from the present investigation it was concluded that the fraction of vanadium recovery increasing with increasing of temperature ,naoh molarity ,leaching time and decreasing with particle size increasing.: 2.the optimum leaching time depended greatly on specific conditions of test ;temperature, particle size and naoh molarity. 3.the selectivity of naoh solution for the recovery of vanadium from spent catalyst was excellent. 4.a complete vanadium recovery was achieved at the following conditions: temperature (100˚c), partical size( 150 mesh), molarity of naoh(4 molar) and leaching time(5 h). references: 1-west , r.c. crc handbook of chemistry and physics , 67 th ed., boca raton, florida, crc press1987 2-haron etl "vanadium recovery from day vanadium mineral using an acid leaching method" ,civil and environment engineering school ,university of science &technology beijing, received 2007 3-stas jamal, ajaj dahdouh , omar al-chayah, "recovery of vanadium, nickel and molybdenum from fly ash of heavy oil-fired electrical power station” , department of chemistry, atomic energy commission„ p.o.box 6091 damascus, syria 2006. 4-lozano l. j. , and c. godínez "comparative study of solvent extraction of vanadium from sulphate solutions by primene 81r and alamine 336”,department of chemical and environmental engineering, polytechnic university of cartagena, campus muralla del mar s/n, 30202, paseo alfonso xiii, 50, cartagena 30203, spain, 29 october 2002. 5-luis etl . "vanadium recovery by leaching in spent catalysts for sulfuric acid study on vanadium recovery from spent catalyst used in the manufacture of sulfuric acid ijcpe vol.11 no.2 (june 2010) 54 production",science&technology. v.8 no.16.p.8590, 2000 6-hansen; donald j. (lewiston, ny), goddard; john b. (grand island, ny), malacarne; oreste j. (grand junction, co)," method for recovering vanadium from vanadium-containing ore " ,no.6/858,917, may 2, 1986 7-jasim salh al-deen , study of the extraction of vanadium by tbp m.sc. anbar university1998. 8-kh. m.mousa,"study of leaching on recovery of vanadium from scale residues of oil-fired power stations”, baghdad university / department of chemical engineering, 1999 . 9-khorfan s., a. wahoud, and y. reda, “recovery of vanadium pentoxide from spent catalyst used in the manufacture of sulfuric acid”,atomic energy commission hydrometallurgy office, damascus, dec. 10 (2002). 10levenspiel, “chemical reaction engineering", 3rd edition, john-wiley and sons inc., new york (1999). 11-rickles,n., chem.eng., march (1965). الخالصة تعتبش عًهيت استشداد انفنبديىو ين انعبيم انًسبعذ انًستههك وانًستخذو في صنبعت حبيض انكبشيتيك ين االيىس انًهًت نكىنت يعتبشيصذس جيذ نهحصىل عهى انفتبديىو وكزنك الهًيت انًىضىع ين اننبحيت انبيئيت ورنك نظشوسيت خفض نسبت انفنبديىو في تشداد انفنبديىو ين يخهفبث انًحفض انًستههك انًستخذو في صنبعت حبيض اطاهتى هزا انبحث بذساست . انًخهفبث قبم طًشهب . يحهىل هيذسوكسيذ انصىديىوبىاسطتانكبشيتيك .يىالسيت هيذسوكسيذ انصىديىو و صين انهظى , انحجى انحبيبي نهًخهفبث , عذة يتغيشاث هي دسجت انحشاسة تأثيشتى دساست iraqi journal of chemical and petroleum engineering vol.17 no.3 (september 2016) 3343 issn: 1997-4884 thermal and catalytic degradation kinetics of high-density polyethylene over nax nano-zeolite ammar s. abbas* and marwa g. saber chemical engineering department – college of engineering – university of baghdad (iraq) *email: dr_ammar19@yahoo.com, ammarabbas@coeng.uobaghdad.edu.iq abstract thermal and catalytic pyrolysis of waste plastics in an inert atmosphere has been regarded as a creative method, since pyrolysis can convert plastics waste into hydrocarbons that can be used either as fuels or as a source of chemicals. natural iraqi kaolin clay was used to synthesis the nax nanozeolite by hydrothermal conditions with average particle size equal to 77.63nm.thermal decomposition kinetics of high-density polyethylene (hdpe) in the absence and presence of catalysts nano nax zeolite was investigated. thermal and catalytic degradation of hdpe was performed using a thermogravimetric analyzer in nitrogen atmosphere under non-isothermal conditions 4, 7 and 10 °c/min heating rates were employed in thermogravimetric analysis (tga) experiments. first-order decomposition reaction was assumed, and for the kinetic analysis coats and redfern (cr) method was used. the apparent activation energy (ea) was evaluated. results showed that the nax nano-zeolite decreases the activation energy (ea) of hdpe pyrolysis further than the thermal pyrolysis. keywords: thermal degradation, hdpe, nax zeolite, tga, coats and redfern, kinetic analysis. introduction the good properties of plastics materials such as light weight, strength and energy efficiency make plastics a necessary part of many industrial applications. annual plastic consumption of the world's increased dramatically. thus, wastes of plastic are increasing rapidly which consider one of the big environmental problems [1]. as a conventional plastic material, polyethylene, with its two types hdpe and low density polyethylene [2], plays an important part in the commodities due to its resistance to microbial or enzymatic degradation also it is a main component of plastic waste from domestic waste [3]. similarly polyethylene is one-third of the global consumption of plastic [4]. several approaches, such as land filling, incineration, biological are already in place, but still appear insufficient or do not conform existing environmental rules [1].thus, alternate methods such as chemical or feedstock recycling which includes conversion of plastics into fuel plays an important process in reducing plastics waste at the same time produce fuel[5] [6]. university of baghdad college of engineering iraqi journal of chemical and petroleum engineering mailto:dr_ammar19@yahoo.com mailto:ammarabbas@coeng.uobaghdad.edu.iq thermal and catalytic degradation kinetics of high-density polyethylene over nax nano-zeolite 34 ijcpe vol.17 no.3 (september 2016) -available online at: www.iasj.net pyrolysis is thermochemical decomposition of organic materials in the absence of oxygen [7]. it can be carried out in the absence of catalyst which is called thermal cracking or thermolysis and catalytic pyrolysis in the presence of a catalyst [4]. the disadvantages of thermal degradation are wide product distribution and requisite of high temperatures, usually more than 500 °c and even up to 900 °c. catalytic degradation of plastics waste offers substantial advantages. on the other hand catalytic pyrolysis gives a means to solve the thermal pyrolysis problems [8]. different catalysts have been used such as silica alumina catalyst [9], fluid catalytic cracking (fcc) catalyst [10] [11], mcm-41[12], molecular sieves and y zeolite [13], other zeolites such as beta zeolite [14], clinoptilolite[15], bentonite [16], zeolite-x [17] or zsm-5 [18], have also been employed for the catalytic decomposition of plastic waste [19]. zeolites materials have excellent properties as catalysts for the plastics pyrolysis waste [20]. the zeolite catalyst combines high acidity with shape selectivity, high surface area and high thermal stability [21]. in addition the nano-sized zeolites have more active sites in catalysis compared with conventional zeolites caused by their larger external surface area [22]. thermogravimetric analysis (tga) consider an excellent mean for studying the kinetics of thermal and catalytic pyrolysis [23], by tga the kinetic parameter of pyrolysis which include the activation energy (ea) and pre-exponential (a) can be calculated. tga is a technique of thermal analysis which measures the rate of change in the weight and the amount of material as a function of temperature or time under controlled atmosphere such as nitrogen, air, or other gases [24]. abbas and shubar [25]study the hdpe pyrolysis in closed system batch reactor and used the tga to found the temperature range of hdpe pyrolysis, it was from 386.5 to 514 °c. kayacan et al. [26] study the waste and raw hdpe thermal decomposition kinetics at 5, 10, 20 and 50 k/min heating rates it was found that the kinetics of the degradation of the hdpe for non-isothermal conditions can be considered as a firstorder reaction and the activation energy for raw hdpe has been calculated between 401 and 470 kj/mol and for the waste hdpe was in the range of 396 to 493 kj/mol. kumar et al. [27] study the tga has been used for the non-isothermal kinetic study of waste hdpe pyrolysis under nitrogen atmosphere at different heating rates 10, 20 and 40°c/min. the activation energy values of waste hdpe have been calculated as 207.43, 268.22 and 473.05 kj/mol at 10, 20 and 40°c/min heating. abbas and mohamed reported tga for hdpe at heating rate equal to 20 °c/min from surrounding temperature to 800 °c in order to know the range of effective temperature for pyrolysis. the decomposition of the hdpe decomposition started at 326 °c and was complete at 495 °c [28]. in the present work, nano nax zeolite was prepared and the kinetics of the thermal degradation and catalytic in presence of nano nax zeolite degradation using tga of virgin hdpe was studied according to cr method. the values of activation for waste hdpe have been obtained in non-isothermal condition assuming first-order reaction kinetic at different heating rates. material and methods materials natural iraqi kaolin clay, sodium hydroxide (naoh) and hdpe pellets http://www.iasj.net/ ammar s. abbas and marwa g. saber -available online at: www.iasj.net ijcpe vol.17 no.3 (september 2016) 35 were purchased from local markets (the source of plastic is sabic company). the main properties of the hdpe are shown in table1. table 1: virgin hdpe pellets physical properties property value average particle diameter, mm 3 density, g/cm 3 0.956 0.963 deflection temperature (at 0.46 mpa),°c 75 – 85 melting point, °c 130 – 135 melt flow index, g/10min 0.05 0.43 nax zeolite preparation kaolin was sieved to a particle size ≤ 75 µm, then mixed with 40% sodium hydroxide solution using (kaolin / naoh = 1/1.5) and fused at 850°c for 3 hours. ten g of naoh was dissolved in 200 ml of distilled water and 14.3 g of fused kaolin was added to the naoh solution. the mixture was stirred until it becomes homogeneous. the mixture was placed in a sealed polypropylene bottle and stored in an oil bath at 60 °c in a programmable electrical furnace for 48 hours. the product obtained was filtered and washed with distilled water for several times until ph value dropped to 8.5 after that the product was dried in an electrical oven for 48 hours at 100 °c followed by calcination at 550 °c for 2 hours. characterization and analysis of prepared nax zeolite the prepared catalyst was characterized by using different technical analysis techniques such as: x–ray diffraction (xrd), atomic force microscope (afm), bet specific surface area and pore volume by iso-9277-2010 method, sodium content by astm d-1428-64 method, and x-ray fluorescence (xrf) to determine the silica content and silica to alumina ratio. results and discussion the xrd pattern of prepared zeolite is shown in figure 1. the patterns indicated that the prepared samples have the structure of zeolite nax when it’s compared with stander structure that shown in figure 2. fig. 1: xrd pattern of prepared zeolite-x http://www.iasj.net/ thermal and catalytic degradation kinetics of high-density polyethylene over nax nano-zeolite 36 ijcpe vol.17 no.3 (september 2016) -available online at: www.iasj.net fig. 2: xrd pattern of standard zeolite-x [29] the comparison between diffraction angle and lattice spacing of prepared and standard nax zeolite is shown in table 2. table 2: angle of diffraction and lattice space for prepared and standard of nax zeolite prepared catalyst standard of catalyst angle (2theta) deg. d, spacing (å) angle (2theta) deg. d, spacing (å) 6.21 14.20 6.12 14.45 10.11 8.73 10.00 8.84 11.80 7.49 11.73 7.54 12.57 7.03 12.25 7.22 15.51 5.70 15.43 5.74 18.49 4.79 18.42 4.81 20.15 4.40 20.07 4.42 21.10 4.20 21.00 4.23 22.56 3.93 22.47 3.95 the silica to aluminum ratio (si/al) of nax zeolite was equal to 1.17 according to xrf analysis which lie in the range of si/al ratio of x zeolite [30] also these results were in a good agreement with the result published by franus [31] who mentioned that the ratio of silica to alumina in nax is about 1.2. where the bet surface area and pore volume of nax zeolite was 255m 2 /g and 0.198 cm 3 /g respectively with sodium content equal to 9.6 wt.%. the particle size distribution of prepared nax from the afm analysis is shown in figure 3, while the average nano particle of nax zeolite was equal to 77.63 nm this result is in a good agreement with the result by ghasemi and younes [32] they recorded the na– x nanocrystals with crystallite size ranging from 70 to 260 nm. http://www.iasj.net/ ammar s. abbas and marwa g. saber -available online at: www.iasj.net ijcpe vol.17 no.3 (september 2016) 37 fig. 3: bar chart of particle size distribution for prepared nax zeolite thermal degradation the thermal decomposition behavior was study by tga analyzer apparatus. two samples prepared to analyze first one by using 20 mg of the hdpe and the second one (18 mg of nax zeolite mixed with 2 mg of hdpe).the two samples were placed separately on the sample holder and pyrolyzed in nitrogen atmosphere in each experiment. thermogravimetric analyses of composites were done with the temperature range from 25 to 550 °c and the tga and dtga data were recorded at different heating rate (4, 7 and 10 °c/min). the tga figures of thermal pyrolysis (sample hdpe) and catalytic pyrolysis in presence of nax zeolite (sample hdpe+nax) are shown in figures 4 and 5 respectively at different heating rates. fig. 4: tga analysis of hdpe 0 20 40 60 80 100 0 100 200 300 400 500 600 w t% temperture, °c hr=10 c/min hr=7c/min hr=4 c/min http://www.iasj.net/ thermal and catalytic degradation kinetics of high-density polyethylene over nax nano-zeolite 38 ijcpe vol.17 no.3 (september 2016) -available online at: www.iasj.net fig. 5: tga analysis of hdpe+nax in figures 4 and 5 the weight loss began slowly then rise gradually followed by the main weight loss zone for all samples that because the hdpe mass starts to change after the first bonds are broken, and when the cracking products are light enough to vaporize to the gas phase. it can be observed that the weight change is very rapid [7] [2]. it is clearly in figures 4 and 5 that there is a shift in the weight loss data to higher temperatures as the heating rate increases, because the rate of heat transfer at various heating rates is different, and the sample reaches degradation temperature in a shorter time when higher heating rates are considered [7] [33] this behavior also realized by kumar and singh [27]. in the tga curve the initial temperature at which the degradation started (ti) and final temperature at which the degradation completed (tf) for each sample is shown in table 3. table 3: started and final temperature of thermal and catalytic hdpe degradation heating rate, °c/min pyrolysis temperature range (ti tf), °c hdpe hdpe+nax 4 370.2-492.8 265-550 7 370.9-463.9 300-550 10 381-526 282-550 table 2 was shown when the heating rates increased, the initial and final degradation temperature for hdpe tend to increased too that because polymer molecules does not have enough time to exhaust the heat with increasing heating rate, leading to slower degradation rate and higher degradation temperature due to slow diffusion of heat in both thermal and catalytic degradation [27]. aboulkas et.al [34] denoted that the degradation of hdpe start at 381 and complete at approximately 581 °c for different heating rate. the pyrolysis reaction in presence of nax zeolite start at lower temperature than that of thermal pyrolysis as shown in table 2 which explain the activity of catalyst. coats and rededfern (cr) kinetic method the non-isothermal kinetics for pyrolysis is usually written as follows: …(1) where x is a conversion of hdpe, and is given by: …(2) 0.00 20.00 40.00 60.00 80.00 100.00 0 100 200 300 400 500 600 w t. % temperture,°c hr=10 c/min hr=7 c/min hr=4 c/min http://www.iasj.net/ ammar s. abbas and marwa g. saber -available online at: www.iasj.net ijcpe vol.17 no.3 (september 2016) 39 where w, wi, and wf, represent the instantaneous, initial, and final weights of the sample. the reaction rate constant k is expressed in terms of the arrhenius equation as: ( ) …(3) and the function f(x) can be written as: …(4) substituting eq. 3 and 4 into eq. 1 gives: ( ) …(5) for a constant heating rate hr=dt/dt, eq. 5 can be rearranged to the following equation: ( ) ( ) …(6) equation 6 represents the differential form of the non-isothermal rate law. the integral method based on coats and redfern (cr) equation is used in this paper, and the approximate integration of eq. 6 gives: [ ] [ ] if n=1 …(7) [ ] [ ] if n …(8) the above two equations are the coats-redfern method. the plot of versus 1/t becomes a linear line for n=1; the plot of versus 1/t is also a linear line for n 1. accordingly, the apparent activation energy ( ) and the apparent frequency factor (a) can be determined from the slope and intercept of the regression line, respectively [35] [36] [1]. the coats redfern method was used to estimate the activation energy at each heating rate by applied equation 7 at 4, 7 and 10 °c/min heating rate for two samples: hdpe alone and hdpe+nax. the plots of cr method for two samples are shown in figures 6 and 7. fig. 6: cr plots at different values of conversion for pyrolysis of hdpe -17 -16 -15 -14 -13 -12 -11 0.00125 0.0013 0.00135 0.0014 0.00145 0.0015 0.00155 0.0016 0.00165 ln (ln (1 -x )/ t 2 ) 1/t 10 c/min 7 c/min 4 c/min http://www.iasj.net/ thermal and catalytic degradation kinetics of high-density polyethylene over nax nano-zeolite 40 ijcpe vol.17 no.3 (september 2016) -available online at: www.iasj.net fig. 7: cr plots at different values of conversion for pyrolysis of hdpe+nax figures 6 and 7 were show the typical plot of ln [–ln (1 – x)/t 2 ] vs. 1/t for 4, 7 and 10 °c/min for two samples. reasonable fits of data to straight lines in this figure indicate that the assumption of first-order kinetics for thermal and catalytic pyrolysis of hdpe is acceptable [7] [27]. the values of ea and a from cr method are shown in table 4. table 4: activation energy and pre-exponential factor by cr method hr [°c/min] hdpe hdpe+nax ea [kj/mol] lna [min -1 ] ea [kj/mol] lna [min -1 ] 4 127.00 20.00 117.38 18.03 7 156.62 25.71 128.21 20.53 10 175.87 28.84 109.68 17.24 table 4 shows the kinetic parameters that were determined at different heating rates. for all samples ea and a are dependent on heating rate and tends to increase as heating rate increases. the average activation energy values by cr method for thermal and catalytic pyrolysis of hdpe are 153.16 and 118.42 kj/mol respectively. activation energy increased with increase in heating rate as a result of very low thermal conductivity of polymeric material and therefore the temperature distribution in the hdpe will be significant at a high heating rate [27]. the different in values of both activation energies and frequency factors at a different heating rate are attributed to variations in thermal lag at different heating rates [1]. the values of ea in table 4 indicated that the presence of nano-catalyst nax decrease the activation energy of hdpe pyrolysis compared with thermal pyrolysis. park et al. [37] reported that the ea for hdpe alone equal to 123 kj/mol at10 k/min by cr method. conclusion nano nax zeolite with 77.63 average nano particles was prepared by used kaolin as source of silica and alumina under hydrothermal condition. the silica to alumina ration for prepared nax zeolite was 1.17. the -17 -16 -15 -14 -13 -12 -11 0.00134 0.00139 0.00144 0.00149 0.00154 0.00159 0.00164 ln (ln (1 -x )/ t 2 ) 1/t 10 c/min 7 c/min 4 c/min http://www.iasj.net/ ammar s. abbas and marwa g. saber -available online at: www.iasj.net ijcpe vol.17 no.3 (september 2016) 41 activity of nax zeolite was tested in the pyrolysis of hdpe. the kinetic parameters of hdpe decomposition under non-isothermal conditions using tga were determined. the tga analysis was shown that the main thermal and catalytic pyrolysis process occurred in the temperature range 282 to 550 °c. the average activation energy values of thermal and catalytic pyrolysis of hdpe have been calculated by cr method was 153.16 and 118.42 kj/mol respectively for first order decomposition reaction at different heating rates. references 1. m. n. almustapha and j. m. andrésen, “recovery of valuable chemicals from high density polyethylene ( hdpe ) polymer : a catalytic approach for plastic waste recycling,” int. j. environ. sci. dev., vol. 3, no. 3, 2012. 2. m. a. ja, “production of liquid fuels from recycled plastics using acidic hnay catalysts,” 2011. 3. m. t. taghizadeh, p. seifiaghjekohal, a. bahadori, and b. zeraatkar, “thermal and catalytic degradation study of polyethylene and investigation the catalytic effect of x-zeolite and silica-alumina on degradation kinetic,” j. iran. chem. res., vol. 2, pp. 195–210, 2009. 4. c. cleetus, s. thomas, and s. varghese, “synthesis of petroleumbased fuel from waste plastics and performance analysis in a ci engine,” j. energy, vol. 2013, pp. 1–10, 2013. 5. m. syamsiro, w. hu, s. komoto, s. cheng, p. noviasri, p. prawisudha, and k. yoshikawa, “co-production of liquid and gaseous fuels from polyethylene and polystyrene in a continuous sequential pyrolysis and catalytic reforming system,” energy environ. res., vol. 3, no. 2, pp. 90–106, 2013. 6. s. kumar and r. k. singh, “recovery of hydrocarbon liquid from waste high density polyethylene by thermal pyrolysis,” brazilian j. chem. eng., vol. 28, no. 4, pp. 659–667, 2011. 7. e. apaydin-varol, s. polat, and a. e. putun, “pyrolysis kinetics and thermal decomposition behavior of polycarbonate – a tgaftir study,” vol. 18, no. 3, pp. 833–842, 2014. 8. j. shah, m. r. jan, f. mabood, and f. jabeen, “catalytic pyrolysis of ldpe leads to valuable resource recovery and reduction of waste problems,” energy convers. manag., vol. 51, no. 12, pp. 2791– 2801, 2010. 9. t. isoda, t. nakahara, k. kusakabe, and s. morooka, “99/02441 catalytic cracking of polyethyleneliquefied oil over amorphous aluminosilicate catalysts,” fuel energy abstr., vol. 40, no. 4, p. 257, 1999. 10. a. m. ribeiro, h. f. m. júnior, and d. a. costa, “kaolin and commercial fcc catalysts in the cracking of loads of polypropylene under refinary conditions,” brazilian j. chem. eng., vol. 30, no. 04, pp. 825–834, 2013. 11. y. lin and m. yang, “catalytic conversion of commingled polymer waste into chemicals and fuels over spent fcc commercial catalyst in a fluidisedbed reactor,” vol. 69, pp. 145–153, 2007. 12. d. federal, “recycling of plastic materials employing zeolite and mcm-41,” rev. mex. ing. química, vol. 5, no. 3, pp. 189– 195, 2006. 13. h. wu, y. shen, d. ma, q. an, n. harada, and k. yoshikawa, “fuel oil production from twohttp://www.iasj.net/ thermal and catalytic degradation kinetics of high-density polyethylene over nax nano-zeolite 42 ijcpe vol.17 no.3 (september 2016) -available online at: www.iasj.net stage pyrolysis-catalytic reforming of brominated high impact polystyrene using zeolite and iron oxide loaded zeolite catalysts,” no. april, pp. 136–146, 2015. 14. c. processing, “hydrocarbon fractions obtained from,” vol. 39, no. 1, pp. 51–56, 2011. 15. e. buzetzki, k. svanova, and j. cvengros, “zeolite catalysts in cracking of natural triacylglycerols,” 44th int. pet. conf., pp. 1–8, 2009. 16. b. parasuram, s. karthikeyan, and s. sundram, “catalytic pyrolysis of polystyrene waste using bentonite as a catalyst,” j. environ. nanotechnol., vol. 2, pp. 97–100, 2013. 17. n. morita, t. wajima, and h. nakagome, “reduction in content of bromine compounds in the product oil of pyrolysis using synthetic hydrotalcite,” vol. 6, no. 4, pp. 262–266, 2015. 18. a. r. auxilio, a. perera, k. kirtania, and s. bhattacharya, “production of diesel from high density polyethylene using mixed catalyst,” chemeca, pp. 1–12, 2011. 19. l. noreña, j. aguilar, v. mugica, m. gutiérrez, and m. torres, “materials and methods for the chemical catalytic cracking of plastic waste,” 2011. 20. a. marcilla, a. gómez-siurana, and d. berenguer, “study of the influence of the characteristics of different acid solids in the catalytic pyrolysis of different polymers,” appl. catal. a gen., vol. 301, no. 2, pp. 222–231, 2006. 21. i. ofoma, “catalytic pyrolysis of polyolefins,” 2006. 22. j. zhu, x. meng, and f. xiao, “mesoporous zeolites as efficient catalysts for oil refining and natural gas conversion,” front. chem. sci. eng., vol. 7, no. 2, pp. 233–248, 2013. 23. n. murichan and p. cherntongchai, “kinetic analysis of thermal degradation of polyolefin mixtures,” int. j. chem. eng. appl., vol. 5, no. 2, pp. 169–175, 2014. 24. e. rostek and k. biernat, “thermogravimetry as a research method in the transformation processes of waste rubber and plastic products for energy carriers ( wte and wtl processes ),” vol. 1, no. 2, pp. 163–171, 2013. 25. a. s. abbas and s. d. a shubar, “pyrolysis of high-density polyethylene for the production of fuel-like liquid hydrocarbon,” iraqi j. chem. pet. eng., vol. 9, no. 1, pp. 23–29, 2008. 26. i. kayacan, “pyrolysis of low and high density polyethylene . part i : non-isothermal pyrolysis kinetics,” pp. 385–391, 2008. 27. s. kumar and r. k. singh, “pyrolysis kinetics of waste highdensity polyethylene using thermogravimetric analysis,” int. j. chemtech res., vol. 6, no. 1, pp. 131–137, 2014. 28. f. a. m. ammar s. abbas, “production and evaluation of liquid hydrocarbon fuel from thermal pyrolysis of virgin polyethylene plastics,” iraqi j. chem. pet. eng., vol. 16, no. march, 2015. 29. m. m. j. treacy and j. b. higgins, “collection of simulated xrd powder patterns for zeolites,” elsevier, p. 13, 2001. 30. m. srikanth, g. r. kumar, and s. giri, “preparation and characterization of nanosized zsm-5 zeolite using kaolin and investigation of kaolin content, crystallization time and temperature changes on the size and crytallinity of products,” vol. 8, no. 3, pp. 247–265, 2007. http://www.iasj.net/ ammar s. abbas and marwa g. saber -available online at: www.iasj.net ijcpe vol.17 no.3 (september 2016) 43 31. w. franus, “characterization of x-type zeolite prepared from coal fly ash,” polish j. environ. stud., vol. 21, no. 2, pp. 337–343, 2012. 32. z. ghasemi and h. younesi, “preparation of free-template nanometer-sized na-a and -x zeolites from rice husk ash,” waste and biomass valorization, vol. 3, no. 1, pp. 61–74, 2012. 33. p. exploration, “kinetics of isothermal and nonisothermal pyrolysis of oil shale,” vol. 28, no. 3, pp. 415–424, 2011. 34. a. aboulkas, k. el harfi, a. el bouadili, m. benchanaa, a. mokhlisse, and a. outzourit, “kinetics of co-pyrolysis of tarfaya ( morocco ) oil shale with high-density polyethylene,” oil shale, vol. 24, no. 1, pp. 15–33, 2007. 35. k. lu, w. lee, w. chen, and t. lin, “thermogravimetric analysis and kinetics of co-pyrolysis of raw / torrefied wood and coal blends,” appl. energy, vol. 105, pp. 57–65, 2013. 36. m. heydari, m. rahman, and r. gupta, “kinetic study and thermal decomposition behavior of lignite coal,” vol. 2015, 2015. 37. j. w. park, s. c. oh, h. p. lee, h. t. kim, and k. o. yoo, “kinetic analysis of thermal decomposition of polymer using a dynamic model,” korean j. chem. eng., vol. 17, no. 5, pp. 489–496, 2000. http://www.iasj.net/ available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.20 no.4 (december 2019) 1 – 6 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: k. m. abed , email: khalid.chemical82@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. kinetics and thermodynamics of peppermint oil extraction from peppermint leaves b. m. kurji a , k. m. abed b , s. a. rashid b and b. a. abdulmajeed b a chemical and petrochemical engineering department –college of engineering-university of anbar – iraq b chemical engineering department – college of engineering.-university of baghdad iraq abstract this work aims to study extraction of essential oil (eo) from peppermint leaves using hydro-distillation methods. the peppermint oil extraction with hydro-distillation method studied the effect of the extraction temperature on the yield of peppermint oil. besides, it also studied the kinetics during the extraction process. the second-order mechanism was adopted in the model of hydro-distillation to estimate many parameters such as the initial extraction rate, capacity of extraction, the constant rat of extraction at various temperatures and activation energy. the results showed that the extraction process is a spontaneous process, since the gibbs free energy has a negative value at all studied temperatures. for example the gibbs free energy at (70, 80, 90, and 100 ºc)were (-2.93, 3.84, -4.75, -5.66) respectively. keywords: hydro-distillation, arrhenius equation, entropy change, enthalpy change, gibbs free energy, peppermint leaves received on 08/09/2019, accepted on 15/10/2019, published on 30/12/1029 https://doi.org/10.31699/ijcpe.2019.4.1 1introduction an eo is a concentrated hydrophobic liquid containing volatile aromatic compounds from plants ‎[1]. essential oils are also known as etheric oils or oil fly ‎[2]. eo is generally derived from one or more plant parts, such as flowers, leaves, stems, bark, wood, roots and seeds ‎[3]. eo is a mixture of saturated and unsaturated hydrocarbons, alcohol, aldehydes, esters, ethers, ketones, oxides, phenols and terpenes that may produce characteristics ‎[4]. essential oils are generally colorless to slightly yellowish and only slightly soluble in water and dissolve fairly well in an organic solvent and mix very well with vegetable oils and fats. many essential oils have antibacterial, anti-fungal, and antiparasitic properties ‎[5],‎[6]. one of the most particular source of plant containing eo is peppermint. peppermint belongs to the family of lamiaceae ‎[4]. peppermint oil is derived from the peppermint plant, a cross between water mint and spearmint, which is indigenous to europe and north america but now grown throughout the world ‎[7]. peppermint oil has been widely used as flavoring in foods, beverage, as a fragrance in soaps, cosmetics, health and tobacco industries [4,7]. the food and drug administration lists peppermint and peppermint oil as ‘‘generally recognized as safe’’ ‎[8], ‎[9]. chemically, the major constituents of the peppermint oil include the terpenes, menthol, menthone, isomenthone, menthyl acetate, menthofuran and 1, 8-cineol[7,8]. peppermint can be used in the medicinal preparations and as a flavoring agent in foods and confectionery [8]. there are several methods can be used for extracting essential oils such as expression and organic solvent distillation processes. however, hydro-distillation is one of the commonly used for several advantages such as simplicity and non-solvent involvement ‎[10],‎[11],‎[12]. the purpose of this research is to study the process of oil extraction from peppermint leaves using a hydrodistillation method. in this research, the effect of temperature to the yield of peppermint oil and kinetics during the extraction process based on a second-order extraction model will be studied. then, studying of the methods for determining the initial extraction rate and the saturated extraction capacity will be conducted. in addition, the energetic aspect of the eo extraction will be studied. the current work presents first tempt to study the parameters of thermodynamic using this type of eo. then, arrhenius equation parameters will be estimated at different temperature. 2materials and methods 2.1. experimental work leaves of the peppermint plants were collected from a local market. the leaves were dried in shade for ten days, and then it was crashed. twenty gram of peppermint leaves were introduced to pyrex extraction flask with 400 ml of distilled water. the flask is equipped with electrical stirrer at 100 rpm. a water bath was used to control the extraction temperature. the extraction of peppermint oil was conductedat different temperature (343k, 353k, 363k and 373k). https://doi.org/10.31699/ijcpe.2019.4.1 b. m. kurji et al. / iraqi journal of chemical and petroleum engineering 20,4 (2019) 1 6 2 the process continued until the equilibrium was reached. then, the peppermint oil was collected and stored at laboratory conditions. fig. 1 shows a schematic diagram of the experimental setup. the concentration of eo was calculated by multiple the volume of eo by the density of oildivided by the total volume of solvent. fig. 1. schematic diagram of the hydro-distillation setup: 1; water bath, 2; thermometer, 3;stirrer, 4; electric motor and 5; condenser 2.2. kinetic model of peppermint oil extraction the second-order extraction kinetics model, is a commonly used model for the solid-liquid-extraction process, was chosen in the present work. (1) where: is rate constant for2 nd -order model, is the concentration of essential oil at saturation (extraction capacity) and is the concentration of peppermint oil at any time t (min). by grouping variables, equation (2) is obtained: (2) the boundary conditions aret = 0, ct= 0 and ct at timet . integrating the rate equation for a 2 nd -order extraction gave equation (3): (3) rearrangeequation (3) to get equation (4): (4) by rearrange equation (4), the rate of extraction (equation 5) can be written as: ⁄⁄ (5) when t approaches 0 the initial extraction rate, hi, as , can be written as equation (6): (6) at any time, the concentration of peppermint oil can be expressed as: ⁄ ⁄ (7) equation(3) can be rearranged to be as shown in equation (8): (8) by plotting experimental values of versus t, the values of the initial extraction rate hi, the saturation concentration addition to the constant of 2 nd -order extraction rate, can be determined using both the slope and intercept. 2.3. activation energy arrhenius equation is given by equation (9), where it can be used for kinetics study. ⁄ (9) where: ( , the extraction rate constant, t (k) is the absolute temperature of extraction process, r (3.814 is gas constant, a ( is arrhenius factor and ( is activation energy of extraction. equation (10), a linear relationship between and can be obtained from equation (9). ( ) (10) where: the arrhenius equation constants, a and are known for the extraction process, while can be calculated. 2.4. thermodynamic parameters thermodynamic parameters for the extraction of peppermint oil were estimated using van’t hoff equation [1]: (11) (12) where: is equilibrium constant, t (k) is absolute temperature of extraction process, r is gas constant, δg⁰, is gibbs free energy, δh⁰, is extraction enthalpy and δs⁰ is extraction entropy. enthalpy and entropy can be calculated via plotting vs . b. m. kurji et al. / iraqi journal of chemical and petroleum engineering 20,4 (2019) 1 6 3 3results and discussions 3.1. effect of extraction temperature fig. 2 shows influence of temperature on extraction of peppermint oil. the effect of extraction temperature on the peppermint oil extraction kinetics was studied from 70 to 100 °c. increasing the temperature of extraction increases peppermint oil yield.for each temperature, the rate of extraction started with sharply increase more than afterwards. the final concentration of eo was increased when the extraction temperature increased as shown fig. 2 this is because the higher temperature increases the rate of peppermint extraction (evaporation) and the diffusion of the peppermint oil during the process becomes faster ‎[2],‎[13],‎[14],‎[15],‎[16],‎[17]. the different concentrations between the peppermint leaves and water phase represent a driving force for the diffusion of soluble oils according to the fundamentals of mass transfer between the phases (fick’s law). the mass transfer rate, then, reaches a zero when the equilibrium state is occurred. in fact, the dissolution process and diffusion process are dominated in the extraction of the eo according to the different concentrations between the solid phase and bulk liquid phase [18]. fig. 2. influence of temperature on the concentration of peppermint oil 3.2. kinetics of peppermint oil distillation peppermint oil extraction process occurs in two successive stages: (i) dissolution and scrubbing process can be created by the fresh solvent (as driving force); (ii) then external diffusion of peppermint oil into the extract giving a much slower stage. this shows phenomena typical of a 2 nd order kinetic model.the plotting of vs. time explained that phenomena. fig. 3 shows the results of this analysis. fig. 3. second-order extraction kinetics of eo in hydro distillation method from peppermint leaves at various temperatures the amount of oil extracted increases rapidly with time at the beginning of the process. it decreases slowly with the time reaching the end of extraction process ‎[10],‎[13],‎[19],‎[20],‎[21]. equation (1) can be used to calculate the rate of extraction for the peppermint oil which is contained in the solid parts used. the value of , cs,and hi, were determined through slope and intercept after linearization step as shown in table 1. table 1. parameters of the second-order kinetic model at various extraction temperatures of peppermint leaves by water temp(⁰c) 70 6.784 0.000509 0.023412 80 7.189 0.000568 0.029371 90 7.770 0.000717 0.043258 100 9.660 0.000806 0.075212 the initial rate of extraction, hi, increased with extraction temperature. also, cs and , of 2 nd –order kinetic model behaved in the same manner. moreover, from fig.4 the capacity of extraction in the high temperature (100 °c) was always superior to that the lower temperature (70 °c). at the high temperature of extraction, the rate was faster than that at low temperature as can be seen in fig.5 ‎[22], ‎[2]. however, at high temperature, the rat constant of extraction was higher than at low temperature. the main reason for these results is that the cell penetration and diffusion are better in the high temperature [2]. b. m. kurji et al. / iraqi journal of chemical and petroleum engineering 20,4 (2019) 1 6 4 fig. 4. response of cs by changing the extraction temperature fig. 5. initial extraction rate (hi) at different temperature 3.3. activation energy the arrhenius equation (9) obtained by plotting ln versus1/t fig. 6. the plot of ln( ) vs. the reciprocal of the absolute temperature allows for calculating arrhenius constant, a, and activation energy, . there was a linear relationship between and with a determination coefficient of 0.9779. from fig. 6, the arrhenius constant, a, is 4.9126 ( , and the activation energy for extraction, , is 55.109 ( showing that the extraction is an endothermic process. fig. 6. response of ln(k), vs. the reciprocal of the absolute temperature(1/t) 3.4. thermodynamic parameters table 2 displays the values ofke, δh, δs and δg respectively at different temperature for the peppermint oil extraction process. while the plot of ln keverses the reciprocal of the absolute temperature 1/t that used to determine the value of thermodynamic parameters, is shown in fig. 7. fig. 7. plotting of lnke vs. 1/t fig. 7 shows the linear dependence of ln k on the reciprocal of the absolute temperature, 1/t, of the peppermint oil extraction. δh and δs were both estimated using the slope and intercept of the straight lines, respectively. the change in gibbs free energy was found from δh and δs using equation (10).the values of δh, δs and δg are presented in table 2. table 2. thermodynamic parameters for extraction of peppermint oil temp. (⁰c) δh⁰(kj/ mo) δs⁰ (j/mol k) ke δg⁰ (kj/mol) 70 28.247 90.905 3.19117 -2.93 80 3.30908 -3.84 90 4 -4.75 100 7.3408 -5.66 the value of δh and δs for the peppermint oil extraction were positive in the ranges of extraction temperature. thus, this extraction process of the peppermint oil is shown to be both irreversible and endothermic. the previous studies reported same results for the extraction of sunflowers oil [23], olive oil [15], soybeans oil ‎[24], cottonseeds oil ‎[25] and hempseed oil ‎[26].the value of δh gave the quantity of energy that the extraction process mixture; i.e., peppermint leave and water, should adsorb so that the peppermint oil extraction process can happen. from table 2, δg was negative which shows that the extraction process of peppermint oil is favorable and spontaneous. the spontaneous nature of the extraction of the peppermint oil was favored with increase the extraction temperature. b. m. kurji et al. / iraqi journal of chemical and petroleum engineering 20,4 (2019) 1 6 5 4conclusion in this study, the kinetics of the eo extraction from peppermint leaves at different temperatures is based on a 2nd-order model. consequently, it can be concluded that the mechanism of the eo extraction proceeds in two steps: a fast dissolution of peppermint oil followed by slow external diffusion of solute from the plant leaves. cs , and the hi can be predicted with this 2nd-order model as a function of the temperature. in accordance with an endothermic process, the yield of peppermint oil is found to increase with extraction temperature. the value of ,55.109 ( ,showed that the extraction process is an irreversible and endothermic process. δg⁰ shows that the extraction process of peppermint oil is favorable and spontaneous. references [1] ouazzou a. a. ,cherrat l., espina l., lorán s., rota c., pagán r., 2011. the antimicrobial activity of hydrophobic essential oil constituents acting alone or in combined processes of food preservation, innovative food science and emerging technologies , 12 ( 3): 320-329. [2] kusuma h. s. and mahfud m., 2017. microwave hydrodistillation for extraction of essential oil from pogostemoncablinbenth: analysis and modelling of extraction kinetics, journal of applied research on medicinal and aromatic plants, 4:46-54. [3] burt s., 2004. "essential oils: their antibacterial properties and potential applications in foods—a review, 94 (3): 223-253. [4] ali b., al-wabel n. a., shams s., ahamad a., khan s. a., and anwar f., 2015. essential oils used in aromatherapy: a systemic review, asian pacific journal of tropical biomedicine, 5( 8): pp. 601-611. [5] tavares a. c., gonçalves m. j. , cruz m. t., cavalerio c., lopesm. c., canhoto j. and salgueiro l. r. , 2010.essential oils from distichoselinum tenuifolium: chemical composition, cytotoxicity, antifungal and anti-inflammatory properties, journal of ethnopharmacology, 130(3): 593-598. [6] abed k. m., kurji b. m., and abdulmajeed b. a.,2018.extraction and modelling of oil from eucalyptus camadulensis by organic solvent, journal of materials science and chemical engineering, 2015(3): 35-42. [7] loolaie m., moasefi n., rasouli h., and adibi h.,2017. peppermint and its functionality: a review, archive of clinical microbiology, 8(4): 1-16. [8] dai j., orsat v., raghavan g. v., and yaylayan v., 2010. investigation of various factors for the extraction of peppermint (mentha piperita l.) leaves, journal of food engineering, 96 (4): 540-543. [9] grigoleit h.-g. and grigoleitp. , 2005. gastrointestinal clinical pharmacology of peppermint oil, phytomedicine, 12(8): 607-611. [10] gavahian m., farahnaky a., javidnia k., majzoobi m. j. and technologies e., 2012. comparison of ohmic-assisted hydrodistillation with traditional hydrodistillation for the extraction of essential oils from thymus vulgaris l, innovative food science & emerging technologies (14) : 85-91. [11] grigoleit h.-g. and grigoleit p. j. p., 2005. pharmacology and preclinical pharmacokinetics of peppermint oil, phytomedicine, 12(8): 612-616. [12] jeyaratnam n., nour a. h., kanthasamy r., nour a. h., yuvaraj a. r. and akindoyo j. o. ,2016. essential oil from cinnamomum cassia bark through hydrodistillation and advanced microwave assisted hydrodistillation, industrial crops and products, 92: pp. 57-66. [13] rabesiaka l. r., havet j. l., porte c., fauduet h., 2007. solid–liquid extraction of protopine from fumaria officinalis l.—analysis determination, kinetic reaction and model building, separation and purification technology, 54(2): 253-261. [14] abdulraheem i. f., al-rubaye r. t., abed k. m. and abdulmajeed b. a., 2019. extraction of jojba oil using various concentrations of two different solvents, iraqi journal of agricultural sciences, 50(4): under press. [15] eikani m. h., golmohammad f., homami s. s., 2012. extraction of pomegranate (punicagranatum l.) seed oil using superheated hexane, food and bioproducts processing, 90(1): 32-36. [16] kusuma h. and mahfud m., 2018. kinetic studies on extraction of essential oil from sandalwood (santalum album) by microwave air-hydrodistillation method, alexandria engineering journal, 57(2): 1163-1172. [17] sulaiman s., aziz a. a., and aroua m. k., 2013. optimization and modeling of extraction of solid coconut waste oil, journal of food engineering, 114 (2): 228-234. [18] abed k. m. and naife t. m., 2018. extraction of essential oil from iraqi eucalyptus camadulensis leaves by water distillation methods," in iop conference series: materials science and engineering, 454 (1): 012163: iop publishing. [19] ho y.-s., harouna-oumarou h. a., fauduet h. and porte c. , 2005. kinetics and model building of leaching of water-soluble compounds of tilia sapwood, separation and purification technology, 45(3):169-173. [20] meziane s. and kadi h., 2008. kinetics and thermodynamics of oil extraction from olive cake, j am oil chem soc, 85:391–396. [21] uhm j. t. and yoon w. b., 2011. effects of high‐ pressure process on kinetics of leaching oil from soybean powder using hexane in batch systems, journal of food science, 76(6): e444-e449. [22] abed k. m., kurji b. m., and abdulmajeed b. a.,2018. extraction of ocimumbasillicum oil by solvents methods," asian journal of chemistry, 30(5): 958-960. https://www.sciencedirect.com/science/article/pii/s1466856411000634 https://www.sciencedirect.com/science/article/pii/s1466856411000634 https://www.sciencedirect.com/science/article/pii/s1466856411000634 https://www.sciencedirect.com/science/article/pii/s1466856411000634 https://www.sciencedirect.com/science/article/pii/s1466856411000634 https://www.sciencedirect.com/science/article/pii/s1466856411000634 https://www.infona.pl/resource/bwmeta1.element.elsevier-20a1cca2-4595-30bc-914d-448b7b56abfd https://www.infona.pl/resource/bwmeta1.element.elsevier-20a1cca2-4595-30bc-914d-448b7b56abfd https://www.infona.pl/resource/bwmeta1.element.elsevier-20a1cca2-4595-30bc-914d-448b7b56abfd https://www.infona.pl/resource/bwmeta1.element.elsevier-20a1cca2-4595-30bc-914d-448b7b56abfd https://www.infona.pl/resource/bwmeta1.element.elsevier-20a1cca2-4595-30bc-914d-448b7b56abfd https://www.sciencedirect.com/science/article/abs/pii/s0168160504001680 https://www.sciencedirect.com/science/article/abs/pii/s0168160504001680 https://www.sciencedirect.com/science/article/abs/pii/s0168160504001680 https://www.sciencedirect.com/science/article/pii/s2221169115001033 https://www.sciencedirect.com/science/article/pii/s2221169115001033 https://www.sciencedirect.com/science/article/pii/s2221169115001033 https://www.sciencedirect.com/science/article/pii/s2221169115001033 https://www.sciencedirect.com/science/article/pii/s0378874110003740 https://www.sciencedirect.com/science/article/pii/s0378874110003740 https://www.sciencedirect.com/science/article/pii/s0378874110003740 https://www.sciencedirect.com/science/article/pii/s0378874110003740 https://www.sciencedirect.com/science/article/pii/s0378874110003740 https://www.sciencedirect.com/science/article/pii/s0378874110003740 https://file.scirp.org/pdf/msce_2015080713194643.pdf https://file.scirp.org/pdf/msce_2015080713194643.pdf https://file.scirp.org/pdf/msce_2015080713194643.pdf https://file.scirp.org/pdf/msce_2015080713194643.pdf https://file.scirp.org/pdf/msce_2015080713194643.pdf https://www.researchgate.net/profile/arvind_singh56/post/what_are_the_health_benefits_of_mint/attachment/5b11af794cde260d15e2753a/as%3a632812600303624%401527885689563/download/peppermint-and-its-functionality-a-review.pdf https://www.researchgate.net/profile/arvind_singh56/post/what_are_the_health_benefits_of_mint/attachment/5b11af794cde260d15e2753a/as%3a632812600303624%401527885689563/download/peppermint-and-its-functionality-a-review.pdf https://www.researchgate.net/profile/arvind_singh56/post/what_are_the_health_benefits_of_mint/attachment/5b11af794cde260d15e2753a/as%3a632812600303624%401527885689563/download/peppermint-and-its-functionality-a-review.pdf https://www.sciencedirect.com/science/article/abs/pii/s0260877409004440 https://www.sciencedirect.com/science/article/abs/pii/s0260877409004440 https://www.sciencedirect.com/science/article/abs/pii/s0260877409004440 https://www.sciencedirect.com/science/article/abs/pii/s0260877409004440 https://www.sciencedirect.com/science/article/abs/pii/s0944711305001066 https://www.sciencedirect.com/science/article/abs/pii/s0944711305001066 https://www.sciencedirect.com/science/article/abs/pii/s0944711305001066 https://www.sciencedirect.com/science/article/pii/s1466856412000033 https://www.sciencedirect.com/science/article/pii/s1466856412000033 https://www.sciencedirect.com/science/article/pii/s1466856412000033 https://www.sciencedirect.com/science/article/pii/s1466856412000033 https://www.sciencedirect.com/science/article/pii/s1466856412000033 https://www.sciencedirect.com/science/article/pii/s1466856412000033 https://www.sciencedirect.com/science/article/abs/pii/s0944711305001078 https://www.sciencedirect.com/science/article/abs/pii/s0944711305001078 https://www.sciencedirect.com/science/article/abs/pii/s0944711305001078 https://www.sciencedirect.com/science/article/abs/pii/s0926669016304988 https://www.sciencedirect.com/science/article/abs/pii/s0926669016304988 https://www.sciencedirect.com/science/article/abs/pii/s0926669016304988 https://www.sciencedirect.com/science/article/abs/pii/s0926669016304988 https://www.sciencedirect.com/science/article/abs/pii/s0926669016304988 https://www.sciencedirect.com/science/article/abs/pii/s0926669016304988 https://www.sciencedirect.com/science/article/pii/s1383586606003042 https://www.sciencedirect.com/science/article/pii/s1383586606003042 https://www.sciencedirect.com/science/article/pii/s1383586606003042 https://www.sciencedirect.com/science/article/pii/s1383586606003042 https://www.sciencedirect.com/science/article/pii/s1383586606003042 http://jcoagri.uobaghdad.edu.iq/index.php/intro/article/view/812 http://jcoagri.uobaghdad.edu.iq/index.php/intro/article/view/812 http://jcoagri.uobaghdad.edu.iq/index.php/intro/article/view/812 http://jcoagri.uobaghdad.edu.iq/index.php/intro/article/view/812 http://jcoagri.uobaghdad.edu.iq/index.php/intro/article/view/812 https://www.sciencedirect.com/science/article/abs/pii/s0960308511000046 https://www.sciencedirect.com/science/article/abs/pii/s0960308511000046 https://www.sciencedirect.com/science/article/abs/pii/s0960308511000046 https://www.sciencedirect.com/science/article/abs/pii/s0960308511000046 https://www.sciencedirect.com/science/article/pii/s1110016817300698 https://www.sciencedirect.com/science/article/pii/s1110016817300698 https://www.sciencedirect.com/science/article/pii/s1110016817300698 https://www.sciencedirect.com/science/article/pii/s1110016817300698 https://www.sciencedirect.com/science/article/pii/s1110016817300698 https://www.sciencedirect.com/science/article/abs/pii/s0260877412004086 https://www.sciencedirect.com/science/article/abs/pii/s0260877412004086 https://www.sciencedirect.com/science/article/abs/pii/s0260877412004086 https://www.sciencedirect.com/science/article/abs/pii/s0260877412004086 https://iopscience.iop.org/article/10.1088/1757-899x/454/1/012163/meta https://iopscience.iop.org/article/10.1088/1757-899x/454/1/012163/meta https://iopscience.iop.org/article/10.1088/1757-899x/454/1/012163/meta https://iopscience.iop.org/article/10.1088/1757-899x/454/1/012163/meta https://iopscience.iop.org/article/10.1088/1757-899x/454/1/012163/meta https://www.sciencedirect.com/science/article/pii/s1383586605001103 https://www.sciencedirect.com/science/article/pii/s1383586605001103 https://www.sciencedirect.com/science/article/pii/s1383586605001103 https://www.sciencedirect.com/science/article/pii/s1383586605001103 https://www.sciencedirect.com/science/article/pii/s1383586605001103 https://aocs.onlinelibrary.wiley.com/doi/abs/10.1007/s11746-008-1205-2 https://aocs.onlinelibrary.wiley.com/doi/abs/10.1007/s11746-008-1205-2 https://aocs.onlinelibrary.wiley.com/doi/abs/10.1007/s11746-008-1205-2 https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1750-3841.2011.02252.x https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1750-3841.2011.02252.x https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1750-3841.2011.02252.x https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1750-3841.2011.02252.x https://www.researchgate.net/profile/khalid_m_abed/publication/324091863_extraction_of_ocimum_basillicum_oil_by_solvents_methods/links/5ac3da0c0f7e9becc9d492fb/extraction-of-ocimum-basillicum-oil-by-solvents-methods.pdf https://www.researchgate.net/profile/khalid_m_abed/publication/324091863_extraction_of_ocimum_basillicum_oil_by_solvents_methods/links/5ac3da0c0f7e9becc9d492fb/extraction-of-ocimum-basillicum-oil-by-solvents-methods.pdf https://www.researchgate.net/profile/khalid_m_abed/publication/324091863_extraction_of_ocimum_basillicum_oil_by_solvents_methods/links/5ac3da0c0f7e9becc9d492fb/extraction-of-ocimum-basillicum-oil-by-solvents-methods.pdf https://www.researchgate.net/profile/khalid_m_abed/publication/324091863_extraction_of_ocimum_basillicum_oil_by_solvents_methods/links/5ac3da0c0f7e9becc9d492fb/extraction-of-ocimum-basillicum-oil-by-solvents-methods.pdf b. m. kurji et al. / iraqi journal of chemical and petroleum engineering 20,4 (2019) 1 6 6 [23] azmir j., zaidul i. s. m., rahman m. m., sharif k. m., mohamed a., shahen f., jahurul m. h. a., ghafoor k., norulaini n. a. and omar a. k. m. ,2013. techniques for extraction of bioactive compounds from plant materials: a review, journal of food engineering, 117 (4): 426-436. [24] khasawneh r. f., 2017. leaching of jojoba oil , journal of natural sciences research, 7(10): 49-62. [25] topallar h. and geçgel ü., 2000. kinetics and thermodynamics of oil extraction from sun ower seeds in the presence of aqueous acidic, turkish journal of chemistry, 24(3): 247-254. [26] rodrigues c. e., aracava k. k. and abreu f. n., 2010. thermodynamic and statistical analysis of soybean oil extraction process using renewable solvent, international journal of food science and technology, 45(11): 2407-2414. ركيات وديناميكيات استخالص زيت النعناع من اوراق النعناعدراسة ح 2عبدالمجيد بسمة عباسو 2سرمد عبدالرزاق رشيد ,2خالدمحسن عبد , 1محسن كرجيبدور العراق -االنبار جامعة –الهندسة كمية -الكيميائية و البتروكيميائية الهندسة قسم 1 العراق –بغداد جامعة –الهندسة كمية –الكيمياوية الهندسة قسم 2 الخالصة زيت الطيارة من اوراق النعناع بطريقة التقطير المائي. استخالص استخالص الزيوتالى تهدف الدراسة هذه المنتجة. الزيت كمية عمى االستخالص حرارة درجة تاثير درست المائي التقطير بطريقة النعناع انيكية عمى ميك عممية التقطير المائي باالعتماد عممية االستخالص . بعد ذلكل كذلك تم دراسة حركية التفاع الموديل من الدرجة الثانية قد درست لحساب ثابت معدل االستخالص و قدرة االستخالص في حالة االشباع و مختمفة. أظهرت النتائج أن عممية االستخالص هي المعدل االستخالص األولي مع درجات حرارة وطاقة التنشيط درجات الحرارة المدروسة. عمى سبيل المثال ، عممية تمقائية ، ألن طاقة جبس الحرة لها قيمة سالبة في جميع ( 5.66-، 4.75-، 3.84-، 2.93-( هي )ºم 177، و 97، 87، 77كانت طاقة جبسالحره عند ) عمى التوالي. ورق : التقطير المائي ، االستخالص ، معادلة أرينيوس ، تغيير اإلنتروبيا ، التغير الحراري ، طاقة كبس الحره, كممات مفتاحية النعناع https://www.sciencedirect.com/science/article/abs/pii/s0260877413000277 https://www.sciencedirect.com/science/article/abs/pii/s0260877413000277 https://www.sciencedirect.com/science/article/abs/pii/s0260877413000277 https://www.sciencedirect.com/science/article/abs/pii/s0260877413000277 https://www.sciencedirect.com/science/article/abs/pii/s0260877413000277 https://www.sciencedirect.com/science/article/abs/pii/s0260877413000277 https://journals.tubitak.gov.tr/chem/abstract.htm?id=4012 https://journals.tubitak.gov.tr/chem/abstract.htm?id=4012 https://journals.tubitak.gov.tr/chem/abstract.htm?id=4012 https://journals.tubitak.gov.tr/chem/abstract.htm?id=4012 https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2621.2010.02417.x https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2621.2010.02417.x https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2621.2010.02417.x https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2621.2010.02417.x https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2621.2010.02417.x ( iraqi journal of chemical and petroleum engineering )university of baghdad college of engineering iraqi journal of chemical and petroleum engineering vol.17 no.4 (december 2016) 2533 issn: 1997-4884 study of the performance of paraffin wax as a phase change material in packed bed thermal energy storage system lubna a. naeem*, tahseen a. al-hattab** and majid i. abdulwahab* *chemical engineering department – college of engineering university of baghdad **chemical engineering department university of babylon abstract the present work deals with an experimental investigation of charging and discharging processes in thermal storage system using a phase change material pcm. paraffin wax was used as the pcm which is formed in spherical capsules and packed in a cylindrical packed column which acted as an energy storage system. air was used as the heat transfer fluid htf in thermal storage unit. the effect of flow rate and inlet temperature of htf on the time of charging and discharging process were studied. the results showed that the faster storage of thermal energy can be made by high flow rate of heat transfer fluid htf and high inlet temperature of heat transfer fluid. it was found that at 65°c htf inlet temperature, the melting and solidification processes accelerated by 27.9% and 57.14% respectively, when the flow rate was increased from 9 to 24 l/s. also, when the htf inlet temperature changed from 65°c to 80°c, the time needed to complete melting process decreased by 38.8%. key words: phase change material pcm, paraffin wax, heat transfer fluid htf, thermal energy storage tes. study of the performance of paraffin wax as a phase change material in packed bed thermal energy storage system lubna a. naeem, tahseen a. al-hattab and majid i. abdulwahab 32 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 33 introduction in the commercial, industrial, and utility field the energy required vary on daily, weekly, and seasonal bases. these required to energy can be matched with the using of thermal energy storage (tes) systems that operate synergistically. the use of tes for thermal applications such as space and water heating, cooling, air-conditioning, and so on has recently received much attention. tes deals with the storage of energy by cooling, heating, melting, and solidifying material. the thermal energy becomes available when the process is reversed. storage by causing a material to raise or lower in temperature is called sensible heat storage. its effectiveness depends on the specific heat of the storage material and, if volume is important, on its density. the rocks or ground used as storage medium in this type. the storage by phase change (with no change in temperature) is type of (tes) known as latent heat storage. latent heat storage systems store energy in phase change materials (pcms), with the thermal energy stored when the material changes phase, usually from a solid to a liquid. the specific heat of melting/freezing and the temperature at which the phase change occurs are of design importance. both sensible and latent tes also may occur in the same storage material [1]. the thermal energy storage in packed bed was used in various applications, such as in retrieving waste heat system and in solar energy storage system that used for air conditioning system with solar energy. the major advantage of these systems is that it provides large surface area to volume ratio, leading to a good heat transfer process. the phase change materials in packed bed have large storage density compared to other storage systems [2, 3]. paraffin wax was considered as an important material capable of storing energy through phase change. these have the advantage of very high stability over repeated cycles of latent tes operation without degradation. so, paraffin waxes were considered as good pcm candidates [4, 5]. paraffin wax have desirable properties, it is safe, non-interacting, and congruous with all materials that consist of containers, high latent heat, low or no supper cooling, chemically stable, and different phase change temperature. this leads to make paraffin wax widespread in latent heat thermal energy storage (lhtes) [6, 7 and 8] chen and yue [9] studied experimentally and theoretically the type of water-ice cool storage that packed in capsule, and used for air conditioning. the model used for estimation the thermal properties is one-dimensional porous-medium model. they used water as phase change material pcm that filled capsules of 34mm diameter and packed in cylindrical tube have dimensions 260 mm length, and 100mm diameter, and alcohol used as heat transfer fluid htf. from their results it was found that there is identification between theoretical and experimental results for different flow rate and inlet coolant temperatures. chen et al. [10] examined the thermal behavior of an encapsulated cold tes during charging for varying inlet coolant temperatures and flow rates. an investigation of the thermal characteristics of paraffin wax in a spherical capsule during freezing and melting showed that the average heat transfer coefficient around capsules is affected by the inlet and initial temperature and reynolds number more during melting than freezing due to the effect of natural convection during melting. benmansour et al. [11] provided a two-dimensional transient analysis of a cylindrical storage tank filled with uniformly sized spherical capsules. the paraffin wax in the randomly packed capsules exchanges heat with air, acting as a heat transfer fluid, and the resulting model is found to agree favorably with observations. cho and choi [12]; reddy et al. [13] designed a thermal energy storage system to store large amount of sensible heat and latent heat in a small unit volume with different solar heat sources. the authors used spherical capsules with different size to store pcm in it and packed bed in cylindrical container with capacity 51 liter, 360mm diameter and 504mm height. the storage unit was insulated with 50 mm thickness of glass wool. the experiments were carried out with different materials (paraffin wax and stearic acid) and different diameter of capsules (68, 58, and 38 mm). from the experimental results, the spherical capsules of diameter 38 mm display the better performance in charging and discharging processes. also, the paraffin wax show little better performance than stearic acid about 5 to 7%, due to the latent heat and thermal conductivity, so it can be considered both paraffin wax and stearic acid good materials for thermal storage unit [13]. bedecarrrats et al. [14] experimentally studied the thermal performance of water as phase change material pcm encapsulated in spherical capsules which packed in fixed bed during melting and solidification processes. the mono ethylene glycol was used as a heat transfer fluid passes around the spherical capsules to charge and discharge the phase change material. the spherical capsules were used with 77 mm diameter and made from blend of polyolefin, filled the metallic cylinder which represent the thermal storage unit. the experimental data showed that the higher heat transfer rate can be obtained with lower inlet coolant temperature and higher flow rate. the present work aimed to study the effect of flow rate and inlet temperature of heat transfer fluid (htf) on the thermal performance of storage system during melting and solidification processes of pcm. experimental investigation the experimental set up used to study the thermal performance of tes system is shown in figure 1. it consists of insulated cylindrical thermal energy storage (tes) tank of 25 cm diameter and 50 cm height, filled with spherical capsules that contain pcm. electrical heater was used to supply heat to the htf; a rotameter was used to measure the flow rate of htf; refrigeration device was installed in order to cool the air in order to reduce the time of experiment. the spherical capsules that contain paraffin wax (melting point 58 of oc) were 4 cm in diameter and they were made from hdpe. pcm capsules were packed as a fixed bed with 4 layers in the cylindrical tank which was insulated with glass wool of thickness 5 cm to prevent heat losing. four thermocouples are located in the axial direction of the cylindrical tank to record the temperature of pcm and htf at each layer. other thermocouples were located at the top and bottom of the storage unit to record the temperature of htf at inlet and outlet point. a mineral tray was used between each layer of spherical capsules to provide/create uniform void spacing between capsules and layers as well. the thermo physical properties of pcm are given in table 1. table 1: thermo-physical properties of pcm melting temperature °c 56-58 latent heat kj/kg 154.21 density kg/m3 885 specific heat kj/m3k 2269 thermal conductivity w/m.°c solid at 15 °c 0.2499 liquid at 60 °c 0.2397 the volumetric flow rates of htf used in the experiments are 9, 14, 19, and 24 l/s. the blower was used to circulate the htf through the storage unit. the inlet temperature of htf was controlled by using a pid controller. the variables studied during the process include, different air inlet temperatures and air flow rate, while during the discharging process, different air flow rate were used. initially, the temperature of pcm capsule was maintained at 30-33 °c and as the htf exchanges energy to pcm, it heated up to its melting temperature. later, heat is stored as latent heat once the pcm melted and becomes liquid. the energy was then stored as sensible heat in liquid pcm. temperature of the pcm and htf are recorded at intervals of 2 minutes. aair conditioning device, bblower, cmanometer, dorifice meter, erotameter, f electric heater, g-rode heater, h-sensor for inlet air, ites tank, jspherical capsules, kthermocouples sensor, ldata logger, mpc fig. 1: schematic diagram of the experimental setup results and discussion 1. charging process the void fraction of the thermal storage tank (packed bed) packed with 4 cm hdpe spherical capsules was 0.4309. the temperature distribution of pcm and htf are recorded through the charging process for different flow rate and different inlet temperatures of heat transfer fluid. 1.1. temperature histories of pcm and htf the temperature histories of pcm and htf at four layers (l1, l2, l3 andl4) of the tes tank are shown in figures 2 and 3. the pcm temperature distribution during melting process was displayed in figure 2 for volumetric flow rate of 0.024 m3/sec and porosity of 0.4309. it was observed that the pcm temperature (tp) increases rapidly at the beginning of the charging period, remains nearly constant around 57 °c during melting process and again increases sharply during heating of liquid pcm. it was found also that the first layer the pcm was completely charged (melted) at nearly 85% of the total charging time due to the high temperature difference between pcm and htf. the charging process was terminated when the pcm temperature in all the layers reaches 65 °c. fig. 2: temperature history of pcm during charging process (q= 24 l/s; thtf=65) figure 3 displays the thermal performance of the htf inside the storage tank, for a volumetric flow rate of 24 l/sec and porosity of 0.4309. from figure 3 it is observed that at all layers, the htf temperature increases rapidly, this is attributed to the absence of thermal resistance that offered by air to the heat flow and the high driving force (temperature difference) at the first segment. also, it is noticed that there was higher increase in air temperature than in pcm temperature as more quantity of heat is absorbed by the air than the amount of heat given to the pcm. this is attributed to the higher solid pcm thermal resistance for heat flow [16]. fig. 3: temperature history of htf during charging process (q= 24 l/s; thtf=65) 1.2. effect of htf flow rate figure 4 shows the effect of varying the volumetric flow rate of htf (9, 14, 19 and 24 l/sec) on the charging process of the storage tank. it was found that there was a great influence of increasing volumetric flow rate on the melting process of pcm. the increase of flow rate from 9 to 24 l/sec led to a decrease in the time required for the complete charging process. it was noticed from the figure that the time of charging process is lowered by 9.3%, 16.3% and 27.9% when the flow rate is raised from 9 to 14, 9 to 19 and 9 to 24 l/sec respectively. this is due to that the increase in fluid flow rates causes an increase in surface heat transfer coefficient between the htf and pcm capsules. therefore, the time required for charging process was greatly affected by the volumetric flow rate in the storage tank. this is in agreement with reddy et al. [13] who used paraffin wax with melting point of 61 oc and stearic acid with melting point 57 oc as pcms. and water was being used as htf. fig. 4: effect of htf flow rate on charging time at l1 1.3. effect of htf inlet temperature figure 5 shows the relation between the pcm temperature and the charging time. it is observed that the htf temperature was changing from 65 to 80 ºc to create the comparison with the charging time. the charging time needed to reach 65 ºc is considered and it various with different inlet temperature. it was noted that the increase in htf temperature causes an increase in the pcm temperature due to the large temperature difference between htf and pcm and therefore, higher heat transfer rate. a temperature of 65 ºc was reached in 82, 94, 106 and 134 minutes when the inlet temperature was 80, 75, 70 and 65 ºc respectively. it was observed that in 61% time the paraffin wax in layer 4 reached 65 ºc when inlet temperature is 80 ºc, whereas it took 70% and 79% of time when the inlet temperature was 75 ºc and 70 ºc respectively [16]. this is in agreement with reddigari et al. [17] who used paraffin as pcm with melting point 61 °c and water as htf in a tes system with different htf inlet temperatures 66, 68, and 70 °c. fig. 5: effect of different htf temperatures on charging time at l4 2. discharging process the temperature variation of pcm and htf was recorded at porosity 0.4309 for different flow rates of htf ranging from 9 to 24 l/sec through the discharging process. 2.1. temperature histories of pcm and htf the discharging process is uniform process at which the pcm start to solidify from the surface toward the center of the capsules. the temperature histories of pcm and htf at four layers (l1, l2, l3 and l4) of the tes tank are shown in figures 6 and 7. figure 6 shows the temperature distribution of pcm in discharging process with porosity of 0.4309 and for volumetric flow rate of 24 l/sec. from the figure, it is clear that there was three regions; at the first region, the pcm temperature (tp) decreased gradually at the beginning of the discharging period, at second region tp remained nearly constant around 57-56 °c, this is the solidification point, and then at the third region, tp decreased sharply through the cooling of solid pcm to nearly 37 °c.the pcm in the solidification point at l4 is completely discharged at nearly 39.7% of the total discharging time. the discharging process is terminated when the pcm temperature in all the layers reached 35 °c. fig. 6: temperature history of pcm during discharging process (q= 24 l/s; thtf=65) figure 7 represents the temperature variation of the htf inside the storage tank for a volume flow rate of 24 l/sec and porosity of 0.4309. it is observed from figure 7 that the temperature of the htf at all the layers decreased rapidly, this is due to that there was no resistance offered by the air to heat flow and high driving force (temperature difference) at the beginning of the process. also, the rate of decrease in temperature is higher in air than in the pcm as a more quantity of heat is absorbed by the air than the amount of heat given to the pcm. this is due to the higher resistance offered by the liquid pcm for heat flow. fig. 7: temperature history of htf during discharging process (q= 24 l/s; thtf=65) 2.2. effect of htf flow rate the discharging process was carried out in different volumetric flow rates (9, 14, 19, and 24 l/sec) to study the effect of changing the volumetric flow rate on the discharging time. figure 8 displays the temperature distribution over a period of time. it was observed that the discharging time also decreased to reach 35 °c with the increase in volumetric flow rate of htf, due to increase heat transfer coefficient that lead to increase heat transfer process. the percent decreased were 28.5%, 53.5%, and 57.14% when the flow rate was increased to 14, 19, and 24 l/sec respectively [16]. fig. 8: effect of htf flow rate on charging time at l1 conclusion thermal energy storage system was studied with storage sensible and latent heat in pcm with the air used as working fluid. it is concluded that the volumetric flow rate has significant effect on the heat extraction rate from the air and heat recovered to the air which in turn affects the rate of charging and discharging of the tes tank. initially, tp was increased rapidly until reaching the phase change temperature at which it approximately remained constant until the phase change finished and then increased until reaching the inlet htf temperature. in discharging, tp initially decreased rapidly until it reached the phase change region at which tp remained approximately constant and then it continuously decreased until it reached 35 °c. charging and discharging time decreased with increase volumetric flow rate q from 9 to 24 l/s by 27.9% and 57.14% respectively, and it decreased about 38.8%.with increase of htf inlet temperature from 65 to 80 °c. therefore, the high rate of charging and discharging process can achieved with high flow rate and high inlet temperature of htf. nomenclature and abrevations tes thermal energy storage htf heat transfer fluid pcm phase change material tp temperature of pcm (°c) hdpe high density poly ethylene l1 the pcm in capsule at layer one l2 the pcm in capsule at layer two l3 the pcm in capsule at layer three l4 the pcm in capsule at layer four. q volumetric flow rate (liter/s) s second references 1. dincer i., and m.a. rosen, 2011, "thermal energy storage: systems and applications", 2nd ed., john wiley & sons, ltd. 2. regin a. f.; s.c.solanki; and j.s.saini, 2008, "heat transfer characteristics of thermal energy storage system using pcm capsules: a review', renewable and sustainable energy reviews, vol. 12, p. 2438-2458. 3. regin a. f.; s.c. solanki; and j.s. saini; 2009, "an analysis of a packed bed latent heat thermal energy storage system using pcm capsules: numerical investigation", renewable energy, vol. 34, p. 1765-1773. 4. roxas-dimaano m.n., and t.watanabe, 2002, "the capric and lauric acid mixture with chemical additives as latent heat storage materials for cooling application, energy vol.27, p.869–888. 5. zhang y., g.zhou, k.lin, q.zhang, and d. di, 2007, "application of latent heat thermal energy storage in buildings: state-of-the-art and outlook", building and environment vol.42, p.2197–2209. 6. abhat a., 1983, "low temperature latent heat thermal energy storage: heat storage materials", solar energy, v.30, no.4, p.313-331. 7. sharma s. d., and k. sagara, 2004, "latent heat storage material sand systems: a review", int. j. green energy, vol.2, p.1-56. 8. himran s., a. suwono and g. a. mansoori, 1994, "characterization of alkanes and paraffin waxes for application as phase change energy storage medium", energy source,vol.16, p.117-28. 9. chens. l.,and j. s. yue,1991, "thermal performance of cool storage in packed capsules for air conditioning", heat recovery systems & chp vol. 11, no. 6, p. 551-561. 10. chen, s.l., c.l. chen, c.c.tin, t.s. lee, and m.c. ke, 2000, "an experimental investigation of cold storage in an encapsulated thermal storage tank", experimental thermal and fluid science 23, p.133–144. 11. benmansour a., m. hamdan, and a. bengeuddach, 2006, "experimental and numerical investigation of solid particles thermal energy storage unit, applied thermal engineering 26, p.513–518. 12. cho k., and s.h. choi, 2000, "thermal characteristics of paraffin in a spherical capsule during freezing and melting processes", int. j. of heat and mass transfer 43, p.3183–3196. 13. reddy r.m., n. nallusamy, and k. h. reddy, 2012, "experimental studies on phase change material-based thermal energy storage system for solar water heating applications", j. of fundamentals of renewable energy and applications, v.2, 6 pages. 14. bedecarrats j.p., j. castaing-lasvignottes, f. strub, j.p. dumas, 2009, " study of a phase change energy storage using spherical capsules", part 1: experimental results, energy conversion and management 50, p.2527-2536. 15. mettawee e. b. s., e. i. eid and sh .a. m. amin, 2012, "experimental study on space cooling with pcm thermal storage", j. of app. sci. research,v.8 n.7, p.3424-3432. 16. naeem l. a., 2016, "theoretical and experimental study of thermal analysis in a fixed bed packed with nanoparticles enhanced phase change materials nepcm", ph.d. thesis, university of baghdad. 17. reddigari m. r., n. nallusamy, a. p. bappala, and h. r. konireddy, 2012, "thermal energy storage system using phase change materials – constant heat source", thermal science, vol. 16, n. 4, p. 1097-1104. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.20 no.3 (september 2019) 49 – 57 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: basim o. hasan , email: basimohasan13@gmail.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. corrosion of carbon steel in oxygen and nacl concentration cells: the influence of solution temperature and aeration muayad f. hamad, huda d. abdul kader, hussein a. alabdly, basim o. hasan, israa s. m. ali department of chemical engineering, al-nahrain university, iraq abstract corrosion rate tests were carried out on carbon steel under concentration cells conditions of oxygen and sodium chloride. the effect of aeration in one compartment on the corrosion rate of both coupled metals was determined. in addition, the effects of time and temperatures on the corrosion rate of both coupled metals and galvanic currents between them were investigated. corrosion potentials for the whole range of operating conditions under concentration cell conditions were also studied. the results showed that under aeration condition, the formation of concentration cell caused a considerable corrosion rate of the carbon steel specimens coupled in different concentrations of o2 and nacl due to the galvanic effect. aerating one compartment caused a noticeable increase in the corrosion rate of the coupled specimen in the other compartment due to the galvanic effect. increasing temperature caused unstable trends in the free and galvanic corrosion potentials. increasing the temperature led to an increase in the corrosion rate for both metals. keywords: carbon steel, corrosion rate, concentration cell, galvanic current, temperature, sodium chloride received on 14/04/2019, accepted on 08/07/2019, published on 30/09/1029 https://doi.org/10.31699/ijcpe.2019.3.7 1introduction the oxygen concentration cell is a case in which corrosion cell is established, due to uneven exposure of the metal to air which influences the corrosion behavior of the metal ‎[1]. this case is sometimes called differential aeration. a complete understanding of differential aeration mechanism is difficult due to the effect of complicated phenomena that may occur at the metalliquid interface such as: passivity, change of surface morphology, change of local ph. gruyter et al. ‎[2] stated that for several decades the concepts of differential aeration have not been really proved by experimental works and these may fail in some occasions. they demonstrated that the differential aeration is not necessarily causing an increased corrosion of the oxygenstarved metal. additionally, the formation of corrosion product, local fluid motion, the electrochemical potential of the metal can be altered by electrochemical transport through operation of concentration cells ‎[3]. this type of corrosion occurs normally when the metal surface is exposed to two environments of different oxygen concentration such us underground corrosion of pipes, tanks, and other structures. in this case the corrosion is slow but destructive. the common terms for this type of corrosion include crevice corrosion, oxygen screening, and poultice action; the difference in oxygen concentration produces a potential difference and thus causes a current flow. anodic and cathodic areas are established on the metal surface forming a corrosion cell. the severity of corrosion is dependent on the different prevailing conditions such as the presence of salt, the temperature, and the moisture or solution nature. the substantial difference of corrosion rate between anode and cathode expresses an acceleration of corrosion due to the oxygen concentration difference. typical examples of the corrosion due to the o2 concentration cell are the water-line corrosion (it is observed in steel water tanks partially filled with water) and pitting corrosion ( observed when dust particles or oil drops deposited over the metal surface)) ‎[4], ‎[5]. laque ‎[6], ‎[7] found that that the corrosion proceeded along the periphery for copper disk where the transport of oxygen was higher. conversely, the iron disks spinning under same conditions corroded at the center where there is a decelerated transport of oxygen. the active-passive transition can also appear depending on the electrode area, oxygen amount, and solution electrical conductivity ‎[8], ‎[9]. oxygen concentration cells can also causes crevice corrosion in some metals such nickel, aluminum, and stainless steels, and other passive metals that are exposed to aqueous environments such as seawater ‎[3]. the aim of the present work is to study the corrosion behavior of carbon steel under the influence of oxygen concentration cells in nacl solution at different temperatures. https://doi.org/10.31699/ijcpe.2019.3.7 m. f. h., h. d. abdul kader, h. a. alabdly, b. o. hasan and i. s. m. ali / iraqi journal of chemical and petroleum engineering 20,3 (2019) 49 57 05 2experimental work fig. 1 shows a schematic diagram of the experimental set up. it is composed of water bath, zero-resistance ammeter (zra), two beakers containing the corrosive nacl solutions, air pump of a flow rate of 2.5 l/ min, specimens, salt bridge to ensure electrical connect of the two compartments. the apparatus contained also saturated calomel electrode (sce) and voltmeter to measure the potentials of the specimens under corrosion conditions and digital balance. carbon steel coupons of dimensions of 40 × 40 × 0.2 mm were used for corrosion tests. they were polished with 400 and 600 grid emery papers, washed with distilled water, and then rinsed with ethanol for 5 minutes. after that the specimens were allowed to dry and placed in oven at 80 o c for five minutes for complete drying ‎[10], ‎[11]. then the specimens were placed in a vacuum desiccator over a high activity silica gel until use. after preparing the nacl solution, the specimens were exposed to the corrosion environment for 2.5 h under specified operating conditions. the experiments included two parts: free corrosion and galvanic corrosion. in free corrosion tests, the weight loss of specimens under different operating conditions of temperature and aeration was determined as well as the potential variation with time. after each test, the specimens were cleaned carefully by water with brushing by plastic brush to remove the corrosion products. then, the specimens were placed in 5% hcl containing organic inhibitor (hexamine) to ensure the removal of the corrosion product from the specimen surface, rinsed with water, dried by oven at 80 o c for 5 min, and kept in a disscator to cool then weighed. the corrosion rate was determined as: (1) where, w1= initial weight of the specimen, w2= final weight of the specimen, a= surface area of the coupons, t= time of the experiment. in concentration cell galvanic corrosion tests, two types of concentration cells were investigated. first type is an oxygen concentration cell in which air is pumped into a compartment of 0.1n nacl solution containing a cs specimen connected to another compartment containing 0.1n nacl solution with no aeration. the metal under aeration conditions (m1a) was connected to the negative terminal of the zra. due to air pumping a differential aeration cell was established in which a potential difference causes a galvanic current to flow between the two poles. zero resistance ammeter (zra) was used to measure the galvanic current under different operating conditions. at the same time the weight loss of each specimen in the galvanic couple was determined to calculate the corrosion rate. fig. 1. schematic diagram of the experimental apparatus, 1. zero resistance ammeter, 2.voltmeter, 3.salt bridge, 4.carbon steel specimens, 5.water bath, 6.beakers, 7. air pump, 8. calomel electrode the second type concentration cell investigated was a salt concentration cell. in these experiments, a galvanic cell was established between two compartments of different salt concentration under different temperatures with and without aeration. the galvanic current, galvanic potential and weight loss of each specimen in the couple were determined. each experiment was carried at least twice. 3results and discussion 3.1. oxygen concentration cell a. corrosion potential fig. 2 to fig. 5 show the electrode potential vs. time at different temperatures: 25, 35, 45, and 55 o c in the presence and absence of aeration for free corrosion and galvanic coupling in 0.1n nacl solution. in these figures the “free” means no coupling between the two terminal and “galvanic” means the two concentration cell terminals are coupled. it is evident that the aeration condition has a noticeable effect on the free corrosion potential and galvanic corrosion potential. the aeration leads to an increase in o2 concentration shifting the potential to more positive ‎[10], ‎[12], ‎[13]. this is a general trend, but in some occasions the potential with aeration is seen to be more negative than without aeration. this can be attributed to the formation of corrosion product layer which represent a thermal resistance to the current flow leading to increase the resistance polarization which shifts the potential to more negative as has been evidenced by some previous studies ‎[14], ‎[21]. the figures indicate that the cell potential becomes more negative with time due to the passivation of metal surface by the formation of corrosion product film which leads to a decrease in the surface activity ‎[10], ‎[14]. m. f. h., h. d. abdul kader, h. a. alabdly, b. o. hasan and i. s. m. ali / iraqi journal of chemical and petroleum engineering 20,3 (2019) 49 57 05 besides, the formation of corrosion product layer with time prevents the arrival of o2 to the surface which causes a decrease in the potential ‎[14], ‎[15]. the formation of insoluble corrosion products creates a shielding effect ‎[16], ‎[17] and also passivates the metal thermodynamically ‎[18]. it can be seen from fig. 2 to fig. 5 that under galvanic coupling, pumping of the air into one compartment leads to increase the potential difference between the two poles of the galvanic cell. this increase in the potential difference enhances the galvanic corrosion attack of the more active pole. fig. 2. free corrosion and galvanic corrosion potentials of cs in the presence and absence of differential aeration in 0.1 n nacl solutions at 25 o c fig. 3. free corrosion and galvanic corrosion potentials of cs in presence and absence of differential aeration in 0.1 n nacl solutions at 35 o c fig. 4. free corrosion and galvanic corrosion potentials of cs in presence and absence of differential aeration in 0.1 n nacl solutions at 45 o c fig. 5. free corrosion and galvanic corrosion potentials of cs in presence and absence of differential aeration in 0.1 n nacl solutions at 55 o c fig. 6 shows the free corrosion potential of cs under aeration conditions for different temperatures for nonaerated metal. fig. 7 shows the variation of free corrosion potential with time for 0.1n nacl solution at different temperatures with aeration condition. it indicates a considerable more negative in potential with the temperature. this indicates that the high concentration of o2 leads to a decrease in the effect of temperature on the potential. the figures also indicate that the temperature of 55 o c has no effect. the high temperature deteriorates the protective properties of the passive film which results in an increase of the passive current density and their destruction at smaller corrosion rate ‎[19]. m. f. h., h. d. abdul kader, h. a. alabdly, b. o. hasan and i. s. m. ali / iraqi journal of chemical and petroleum engineering 20,3 (2019) 49 57 05 fig. 6. potential of free corrosion for different temperatures and without aeration condition in 0.1n nacl fig. 7. potential of free corrosion for different temperatures and aeration condition in 0.1n nacl fig. 8. galvanic potential for different temperatures and without aeration condition in 0.1 n nacl fig. 8 shows the potential versus time of cs specimen without aeration (m2) connected to cs under aeration (m1a) 0.1n nacl solution at different temperatures. it is clear that the galvanic potential shifts to more positive with increasing temperature. the temperature rise leads to a decrease in the dissolved oxygen concentration which leads to shifting the galvanic potential to more negative. fig. 9 shows the effect of temperature on the variation of potential of aerated pole. the same trend of potential was observed. fig. 9. galvanic potential at different temperatures and aeration condition in 0.1n nacl b. corrosion rates fig. 10 shows the corrosion rate of cs metal versus temperature at different conditions. it can be seen that the corrosion rate increases with increasing temperature for both free and galvanic corrosion with and without aeration. the cr in the presence of air pumping (aeration) is much higher than the case of without aeration. this is ascribed to the increased oxygen concentration in the solution which causes severe attack to the metal. it can be seen that the galvanic coupling causes an increase in the cr for the metals in the non-aerated pole. this is interpreted as follows: the aeration of one pole of the couple leads to increase the concentration of o2 at this pole. this causes an increase in the cathodic reduction of oxygen at this metal which leads to increase the charge transfer through cell leading to an increased anodic reaction at the other pole. this means an increased corrosion rate of the other pole. m. f. h., h. d. abdul kader, h. a. alabdly, b. o. hasan and i. s. m. ali / iraqi journal of chemical and petroleum engineering 20,3 (2019) 49 57 05 fig. 10. corrosion rates of carbon steel under different conditions of 0.1n nacl fig. 11 shows the variation of galvanic current (ig) with time at different temperatures. the figure reveals that the galvanic current of differential aeration cell increases with time reaching to steady asymptotic value after some 20 min. for 35 o c and 45 o c, there is a slight decreasing ig after first few minutes. this decrease is attributed to metal passivation due to the formation of a protective film which grows with time ‎[20]. fig. 11 also shows that the effect of temperature on ig is not systematic. maximum current occurs at 35 o c followed by 25 o c, 55 o c and 45 o c. the effect of temperature on the galvanic current and on the corrosion rate is complicated by affecting two important parameters working in a conflicting way: the oxygen diffusivity and solubility. for the current system during the galvanic attack there is four reactions occurring simultaneously on the two metals of galvanic cell. these reactions are o2 reduction reaction on each metal (m1 and m2) which is cathodic reaction: (2) and anodic reaction of each metal: (3) it can also be noticed that for 45 o c and 55 o c the galvanic current is negative often. this is due to the polarity reverse at these two temperatures. at 25 o c, the solubility of o2 in the solution is high about (7 ppm) ‎[21]. with increasing temperature the solubility of o2 decreases and thus the concentration of o2 in the solution decrease leading to a decrease in the cathodic currents of o2 reduction reaction. the sharp decrease in the o2 concentration causes a change in the polarity leading to change the change the electrode behaviors from cathode to anode and vice versa. the same trend was observed by ‎[22], ‎[23]. since the aerated chamber is connected to the positive terminal of zra, the positive current means that the electrons flow from the aerated pole (m1a) to the nonaerated (m2). when increasing the temperature and with the reduction in o2 concentration, the pumping of air may cause passivation to the aerated pole. in this case, the aerated metal is thought to be passivated and thus become cathode. fig. 11. galvanic current of 0.1 n nacl solutions, first spacemen under aeration condition is coupled to a spacemen without aeration condition 3.2. salt concentration cells the effect of concentration of nacl on the potential with time at 25 o c is presented in fig. 12. the figure indicates that the effect of salt concentration in free condition is higher than that in coupling condition; the corrosion potential is shifted towards more negative values with increasing sodium chloride concentrations. it is evident that the free corrosion potential and galvanic potential decrease with time. in addition, the free corrosion potential is higher than the galvanic potential. this agrees with previous workers ‎[23], ‎[24]. fig. 12. galvanic and free corrosion for different concentration of nacl in without aeration condition m. f. h., h. d. abdul kader, h. a. alabdly, b. o. hasan and i. s. m. ali / iraqi journal of chemical and petroleum engineering 20,3 (2019) 49 57 05 fig. 13 shows the galvanic current versus time in 0.1n coupled to 0.3n nacl solutions at different temperatures for the case of nonaeration. it indicates that the value of galvanic current at t=25 o c is greater than the value of the galvanic current at t=45 o c. this is due to the higher concentration of o2 at 45 o c than at 55 o c. this leads to increase the o2 cathodic reduction reactions and thus ig increases. fig. 13. galvanic current of 0.1 n coupled to 0.3 n nacl solutions at 25 and 45 o c without aeration condition table 1 indicates that the values of corrosion rate for aeration conditions are greater than the corrosion rate in case of without aeration since the amount of oxygen arriving to the surface is higher. in addition, for galvanic coupling (concentration cell), at 25 o c the corrosion rate for the aerated pole (m1 in 0.1n nacl) is lower than that of aerated pole (m2). this can be interpreted as follows: the aeration of m1 causes a shift in the potential of m1 to more positive which also increases the potential of m2 because m2 is galvanically connected to m1. since the solution at m2 is of higher electrical conductivity due to the higher salts concentration, the corrosion rate becomes high for m2. table 1. corrosion rate in (gmd) for 0.1 and 0.3n nacl solution galvanic corrosion temperature, o c without aeration aeration 0.3n (m2) 0.1n (m1) 0.3 n (m2) 0.1n (m1) 20.4 28.2 63.7 55.8 25 fig. 14 shows the variation of corrosion rate with temperature for free and galvanic condition. the figure reveals that the increase in temperature causes an increase in the rate of corrosion in free corrosion conditions. this is in agreement with previous works ‎[25], ‎[26]. when the temperature increases, the solution viscosity decreases leading to an increase in the oxygen diffusion to the metal surface which enhances the corrosion. however, the increased temperature causes a decrease in the o2 solubility due to the escape of o2 to the atmosphere the factor that decreases the corrosion rate ‎[10], ‎[27]. fig. 14. corrosion rate versus temperature for aeration and non-aeration conditions in 0.1n nacl solution fig. 15 presents the galvanic current ig with time for aeration and without aeration conditions when coupling cs specimen 1 (m1) (0.1n nacl solution) and specimen 2 (m2) (0.3n nacl solution). it shows that the absolute value of the current in the case of aeration condition is greater than the case of without aeration condition. the negative values of the current indicate that the current (the electrons) is flowing from the specimen connected to the +ve terminal of the ammeter to the other specimen connected to –ve terminal. that means the current is flowing from 0.1n nacl solution to the 0.3n nacl solution. this is due to the shift of the potential of the aerated specimen to more positive with increases the driving force for galvanic corrosion of nonaerated metal and at the same time the corrosion rate of the aerated metal is also increased. before coupling, the cr of aerated specimen in 0.3n nacl solution was 61.8 gmd and without aeration was 47.2 gmd. when coupling the two specimens with one in aerated 0.3 n nacl solution and the other in non -aerated 0.1n nacl solution, the aeration of 0.3n nacl solution increases the galvanic attack of the specimen in 0.1n nacl solution and increases the corrosion of the specimen in 0.3n nacl solution as shown in table 1 for 25 o c. the increased current with the aeration is due to several reactions occurring simultaneously on the galvanically coupled specimens. these reactions are: carbon steel dissolution in both solution (anodic reactions) and oxygen reduction reactions on both metals (cathodic reactions). at 25 o c, when coupling both specimens in 0.1n and 0.3n nacl solution, the specimen in 0.1n solution is more anodic because its cr is higher as shown in table 1. m. f. h., h. d. abdul kader, h. a. alabdly, b. o. hasan and i. s. m. ali / iraqi journal of chemical and petroleum engineering 20,3 (2019) 49 57 00 this is because the anodic dissolution of specimen 1 is high and thus, the cathodic reduction reaction of o2 on specimen 2 is high. so, specimen 1 is anode and specimen 2 is cathode. when aerating specimen 2, the anodic dissolution of specimen 2 increases and it becomes anode and thus its cr is higher as indicated in table 1. under the aeration conditions the current became rapidly more negative in the minutes, and then the curve converged to slower rate, that is because of the formation of the oh ions in a high rate and grouping on the electrodes ‎[28]. fig. 15. galvanic current of coupling 0.1 n and 0.3n nacl solutions without aeration and with 0.3n nacl solution aerated 4conclusions the following conclusions are drawn from the experimental results: 1for oxygen concentration cell, the cell potential for both poles of the cell decreases with time and increases when the oxygen concentration is increased by aeration. 2the aeration of one-pole of the couple leads to increase the cr in the non-aerated pole. 3the free corrosion potential and the potentials of both poles were found to be decreased (becomes more negative) with temperature increase 4the galvanic current for the oxygen cell increases with time reaching to steady asymptotic value after about 20 min. 5the absolute value of galvanic current (ig) at the different concentrations of nacl in two compartments of the concentration cell under aeration condition is much higher than the non-aerated condition. nomenclature symbols description unit a surface area of specimen m 2 cr corrosion rate g/m 2 .day t time of the experiment min w1 initial weight of the specimen g w2 final weight of the specimen g ig galvanic current ampere abbreviations cs carbon steel gmd gram per square meter per day sce standard calomel electrode zra zero resistance ammeter references [1] j. o. bockris, d. drazic, and a. r. despic, “the electrode kinetics of the deposition and dissolution of iron,” electrochimica acta, vol.4, pp.325–361, aug.1961. [2] j. d. gruyter, s. f. mertens, l. e. temmerman, , "corrosion due to differential aeration reconsidered", journal of electroanalytical chemistry vol.506 ,pp. 61–63,jun.2001. [3] r.w.revie and h. h.uhlig, “corrosion and corrosion control an introduction to corrosion science and engineering” fourth edition, john wiley & sons, inc., hoboken new jersey, 2008. [4] g.p.hinds, , s.zhou, and a.turnbull, “underdeposit test method for assessing performance of corrosion inhibitors,” in eurocorr 2008 (european federation of corrosion, 2008),pp. 1–11. [5] g.p.hinds, cooling, and a.turnbull, “testing of inhibitors for underdeposit corrosion in sour conditions,” in eurocorr 2009 (european federation of corrosion, 2009), pp. 1–9. [6] f.laque, “theoretical studies and laboratory techniques in sea water corrosion testing evaluation” corrosion, vol.13, pp. 33 – 44, may 1957. [7] f.laque,, “electrochemistry and corrosion (research and tests),” journal of the electrochemical society, vol.116 ,pp. 73c–77c,1969. [8] c. g. law, and j. newman , “corrosion of a rotating iron disk in laminar, transition, and fully developed turbulent flow” journal of the electrochemical society, vol. 133 , pp. 37 – 42,1986. [9] n.vahdat, and j.newman, “corrosion of an iron rotating disk” journal of the electrochemical society, vol.120 pp.1682 – 1686,1973. [10] b. k. mahato, c. y. cha, and w. shemlit, , “unsteady state mass transfer coefficients https://www.sciencedirect.com/science/article/pii/0013468661800261 https://www.sciencedirect.com/science/article/pii/0013468661800261 https://www.sciencedirect.com/science/article/pii/0013468661800261 https://www.sciencedirect.com/science/article/pii/0013468661800261 https://www.sciencedirect.com/science/article/pii/s0022072801004521 https://www.sciencedirect.com/science/article/pii/s0022072801004521 https://www.sciencedirect.com/science/article/pii/s0022072801004521 https://www.sciencedirect.com/science/article/pii/s0022072801004521 https://www.wiley.com/en-iq/corrosion+and+corrosion+control:+an+introduction+to+corrosion+science+and+engineering,+4th+edition-p-9780471732792 https://www.wiley.com/en-iq/corrosion+and+corrosion+control:+an+introduction+to+corrosion+science+and+engineering,+4th+edition-p-9780471732792 https://www.wiley.com/en-iq/corrosion+and+corrosion+control:+an+introduction+to+corrosion+science+and+engineering,+4th+edition-p-9780471732792 https://www.wiley.com/en-iq/corrosion+and+corrosion+control:+an+introduction+to+corrosion+science+and+engineering,+4th+edition-p-9780471732792 https://www.researchgate.net/publication/273755832_underdeposit_test_method_for_assessing_performance_of_corrosion_inhibitors https://www.researchgate.net/publication/273755832_underdeposit_test_method_for_assessing_performance_of_corrosion_inhibitors https://www.researchgate.net/publication/273755832_underdeposit_test_method_for_assessing_performance_of_corrosion_inhibitors https://www.researchgate.net/publication/273755832_underdeposit_test_method_for_assessing_performance_of_corrosion_inhibitors https://www.researchgate.net/publication/273755924_testing_of_inhibitors_for_underdeposit_corrosion_in_sour_conditions https://www.researchgate.net/publication/273755924_testing_of_inhibitors_for_underdeposit_corrosion_in_sour_conditions https://www.researchgate.net/publication/273755924_testing_of_inhibitors_for_underdeposit_corrosion_in_sour_conditions https://www.researchgate.net/publication/273755924_testing_of_inhibitors_for_underdeposit_corrosion_in_sour_conditions https://www.researchgate.net/publication/284868925_theoretical_studies_and_laboratory_techniques_in_sea_water_corrosion_testing_evaluation https://www.researchgate.net/publication/284868925_theoretical_studies_and_laboratory_techniques_in_sea_water_corrosion_testing_evaluation https://www.researchgate.net/publication/284868925_theoretical_studies_and_laboratory_techniques_in_sea_water_corrosion_testing_evaluation http://jes.ecsdl.org/content/116/2/73c.abstract http://jes.ecsdl.org/content/116/2/73c.abstract http://jes.ecsdl.org/content/116/2/73c.abstract http://jes.ecsdl.org/content/133/1/37.abstract http://jes.ecsdl.org/content/133/1/37.abstract http://jes.ecsdl.org/content/133/1/37.abstract http://jes.ecsdl.org/content/133/1/37.abstract http://jes.ecsdl.org/content/120/12/1682.abstract http://jes.ecsdl.org/content/120/12/1682.abstract http://jes.ecsdl.org/content/120/12/1682.abstract https://www.sciencedirect.com/science/article/pii/0010938x80900104 https://www.sciencedirect.com/science/article/pii/0010938x80900104 m. f. h., h. d. abdul kader, h. a. alabdly, b. o. hasan and i. s. m. ali / iraqi journal of chemical and petroleum engineering 20,3 (2019) 49 57 05 controlling steel pipe corrosion under isothermal flow conditions”, corrosion science, vol.20, pp.421– 441, 1980. [11] b. o.hasan, "galvanic corrosion of carbon steel–brass couple in chloride containing water and the effect of different parameters", journal of petroleum science and engineering, vol. 124, pp.137–14, dec.2014. [12] b.o. hasan, s.a. sadiq, “corrosion of carbon steel in acidic salt solutions under flow conditions”, msc. thesis dept. of chem. eng., university of alnahrain, baghdad, 2012. [13] b. o. hasan, "galvanic corrosion of aluminumsteel under two-phase flow dispersion conditions of co2 gas in caco3 solution", journal of petroleum science and engineering, vol. 133, pp. 76–84, sep. 2015. [14] q. j. slaiman and b. o. hasan, “study on corrosion rate of carbon steel pipe under turbulent flow conditions” the canadian journal of chemical engineering, vol. 88, pp. 11141120, nov. 2010. [15] b. k.mahato, f. r.stewrd, , and l. w.shimlit, “steel pipe corrosion under flow condition ii mass transfer correlations with temperature effects”, corrosion science j., vol.8, pp.737–749, 1968. [16] n. d. tomashov, “underground corrosion of metals,” in theory of corrosion and protection of metals, 2nd ed., macmillan, 1966, , pp. 399–421. [17] l.s.selwyn, w. r. mckinnon, and v.argyropoulos, “maney publishing models for chloride ion diffusion in archaeological iron,” vol. 46, no. 2, pp. 109–120, 2001. [18] n. d. tomashov, passivity and protection of metals against corrosion. springer us, 1967. [19] b. r.tzaneva, l. b.fachikov, r. g.raicheff, “effect of halide anions and temperature on initiation of pitting in cr–mn–n and cr–ni steel”, corros. eng. sci. technol., vol.41, pp.62, 2006. [20] a.guenbour, r. sanchez-tavar , m.t.montanes, j.garcía-antón , “effect of temperature on galvanic corrosion of nonweld/weld aisi 316l stainless steel in h3po4 ” ecs transactions 25( 37) ,2010,pp. 63– 81. [21] b. o. hasan, s. m. aziz, "corrosion of carbon steel in two phase flow (co2 gas-caco3 solution) controlled by sacrificial anode", journal of natural gas science and engineering ,vol.46, pp. 71-79,oct. 2017. [22] s. k. hasan and p. sisodia, “paniala (flacourtia jangomas) plant extract as eco friendly inhibitor on the corrosion of mild steel in acidic media”, rasayan j. chem. no. 3, vol.4, p.548-553, 2011. [23] s. s. hussein, , b. o.hasan, n. a.al-haboubi, "galvanic corrosion of copper / nickel-chrome alloy in an agitated sulfuric acid solution", alnahrain journal for engineering sciences (njes) vol.21 no.1, pp.133-140,2018. [24] s. yaro, m. a. idan, "corrosion inhibition of galvanic couple copper alloy/mild steel in) cooling water system", iraqi journal of chemical and petroleum engineering, vol. 14, no.4, 19-25, 2013. [25] q. j. m. slaiman and j. c. eirs, " corrosion inhibition of carbon steel in hydrochloric acid under dynamic conditions", iraqi journal of chemical and petroleum engineering, vol.17 no.4, 110, 2016. [26] s.m. mahmood, b. o. hasan, q. j. slaiman, "the effect of time and corrosion products formation on corrosion rate of carbon steel pipe under turbulent flow conditions”, iraqi journal of chemical and petroleum engineering, vol. 8, no. 4, 63-71, 2007. [27] l. l. shreir, r.a.jarman, , and g.t.burstein, , “ corrosion metal / environment reactions” third edition, butterworth-heinemann volume i, great britain, 2000. [28] b. o. hasan, m.f. abdul-jabbar, “cathodic protection of carbon steel in 0.1n nacl solution under flow condition using rotating cylinder electrode”, iraqi journal of chemical and petroleum engineering, vol. 18, no.4, , 2012. https://www.sciencedirect.com/science/article/pii/0010938x80900104 https://www.sciencedirect.com/science/article/pii/0010938x80900104 https://www.sciencedirect.com/science/article/pii/0010938x80900104 https://www.sciencedirect.com/science/article/abs/pii/s0920410514003362 https://www.sciencedirect.com/science/article/abs/pii/s0920410514003362 https://www.sciencedirect.com/science/article/abs/pii/s0920410514003362 https://www.sciencedirect.com/science/article/abs/pii/s0920410514003362 https://www.sciencedirect.com/science/article/abs/pii/s0920410514003362 http://nahrainuniv.edu.iq/en/node/6814 http://nahrainuniv.edu.iq/en/node/6814 http://nahrainuniv.edu.iq/en/node/6814 http://nahrainuniv.edu.iq/en/node/6814 https://www.sciencedirect.com/science/article/abs/pii/s0920410515001989 https://www.sciencedirect.com/science/article/abs/pii/s0920410515001989 https://www.sciencedirect.com/science/article/abs/pii/s0920410515001989 https://www.sciencedirect.com/science/article/abs/pii/s0920410515001989 https://www.sciencedirect.com/science/article/abs/pii/s0920410515001989 https://onlinelibrary.wiley.com/doi/full/10.1002/cjce.20383 https://onlinelibrary.wiley.com/doi/full/10.1002/cjce.20383 https://onlinelibrary.wiley.com/doi/full/10.1002/cjce.20383 https://onlinelibrary.wiley.com/doi/full/10.1002/cjce.20383 https://www.sciencedirect.com/science/article/pii/s0010938x68801313 https://www.sciencedirect.com/science/article/pii/s0010938x68801313 https://www.sciencedirect.com/science/article/pii/s0010938x68801313 https://www.sciencedirect.com/science/article/pii/s0010938x68801313 https://www.worldcat.org/title/theory-of-corrosion-and-protection-of-metals-the-science-of-corrosion/oclc/566614 https://www.worldcat.org/title/theory-of-corrosion-and-protection-of-metals-the-science-of-corrosion/oclc/566614 https://www.worldcat.org/title/theory-of-corrosion-and-protection-of-metals-the-science-of-corrosion/oclc/566614 https://www.jstor.org/stable/1506841?seq=1#page_scan_tab_contents https://www.jstor.org/stable/1506841?seq=1#page_scan_tab_contents https://www.jstor.org/stable/1506841?seq=1#page_scan_tab_contents https://www.jstor.org/stable/1506841?seq=1#page_scan_tab_contents https://www.springer.com/gp/book/9781468417302 https://www.springer.com/gp/book/9781468417302 https://www.tandfonline.com/doi/abs/10.1179/174327806x94027 https://www.tandfonline.com/doi/abs/10.1179/174327806x94027 https://www.tandfonline.com/doi/abs/10.1179/174327806x94027 https://www.tandfonline.com/doi/abs/10.1179/174327806x94027 https://www.researchgate.net/publication/288147637_effect_of_temperature_on_galvanic_corrosion_of_non-weldedwelded_aisi_316l_stainless_steel_in_h3po4 https://www.researchgate.net/publication/288147637_effect_of_temperature_on_galvanic_corrosion_of_non-weldedwelded_aisi_316l_stainless_steel_in_h3po4 https://www.researchgate.net/publication/288147637_effect_of_temperature_on_galvanic_corrosion_of_non-weldedwelded_aisi_316l_stainless_steel_in_h3po4 https://www.researchgate.net/publication/288147637_effect_of_temperature_on_galvanic_corrosion_of_non-weldedwelded_aisi_316l_stainless_steel_in_h3po4 https://www.researchgate.net/publication/288147637_effect_of_temperature_on_galvanic_corrosion_of_non-weldedwelded_aisi_316l_stainless_steel_in_h3po4 https://www.sciencedirect.com/science/article/abs/pii/s1875510017302949 https://www.sciencedirect.com/science/article/abs/pii/s1875510017302949 https://www.sciencedirect.com/science/article/abs/pii/s1875510017302949 https://www.sciencedirect.com/science/article/abs/pii/s1875510017302949 https://www.sciencedirect.com/science/article/abs/pii/s1875510017302949 https://www.researchgate.net/publication/259243508_paniala_flacourtia_jangomas_plant_extract_as_eco_friendly_inhibitor_on_the_corrosion_of_mild_steel_in_acidic_media https://www.researchgate.net/publication/259243508_paniala_flacourtia_jangomas_plant_extract_as_eco_friendly_inhibitor_on_the_corrosion_of_mild_steel_in_acidic_media https://www.researchgate.net/publication/259243508_paniala_flacourtia_jangomas_plant_extract_as_eco_friendly_inhibitor_on_the_corrosion_of_mild_steel_in_acidic_media https://www.researchgate.net/publication/259243508_paniala_flacourtia_jangomas_plant_extract_as_eco_friendly_inhibitor_on_the_corrosion_of_mild_steel_in_acidic_media https://www.iasj.net/iasj?func=article&aid=148057 https://www.iasj.net/iasj?func=article&aid=148057 https://www.iasj.net/iasj?func=article&aid=148057 https://www.iasj.net/iasj?func=article&aid=148057 https://www.iasj.net/iasj?func=article&aid=148057 https://www.iasj.net/iasj?func=fulltext&aid=80306 https://www.iasj.net/iasj?func=fulltext&aid=80306 https://www.iasj.net/iasj?func=fulltext&aid=80306 https://www.iasj.net/iasj?func=fulltext&aid=80306 https://www.iasj.net/iasj?func=fulltext&aid=116438 https://www.iasj.net/iasj?func=fulltext&aid=116438 https://www.iasj.net/iasj?func=fulltext&aid=116438 https://www.iasj.net/iasj?func=fulltext&aid=116438 https://iasj.net/iasj?func=article&aid=4613 https://iasj.net/iasj?func=article&aid=4613 https://iasj.net/iasj?func=article&aid=4613 https://iasj.net/iasj?func=article&aid=4613 https://iasj.net/iasj?func=article&aid=4613 https://iasj.net/iasj?func=article&aid=4613 https://www.twirpx.com/file/751776/ https://www.twirpx.com/file/751776/ https://www.twirpx.com/file/751776/ https://www.twirpx.com/file/751776/ https://www.iasj.net/iasj?func=article&aid=25536 https://www.iasj.net/iasj?func=article&aid=25536 https://www.iasj.net/iasj?func=article&aid=25536 https://www.iasj.net/iasj?func=article&aid=25536 https://www.iasj.net/iasj?func=article&aid=25536 https://www.iasj.net/iasj?func=article&aid=25536 m. f. h., h. d. abdul kader, h. a. alabdly, b. o. hasan and i. s. m. ali / iraqi journal of chemical and petroleum engineering 20,3 (2019) 49 57 05 وكموريد الصوديوم :تاثير درجة حرارة تاكل الفوالذ الكاربوني في خاليا تركيز االوكسجين المحمول والتهوية مؤيد حمد, هدى عبدالقادر, حسين العبدلي, باسم عبيد و اسراء عمي قسم الهندسة الكيمياوية, جامعة النهرين الخالصة اجريت عممية قياس معدل التاكل لمحديد الفوالذي تحت ظروف خاليا التركيز لالوكسجين وممح كموريد وتم دراسة تاثير عامل التهوية الحد اجزاء الخمية عمى معدل التاكل لكال المعدنين المربوطين الصوديوم. باالضافة الى ذلك تم دراسة تاثير الوقت ودرجات الحرارة عمى معدل التاكل لكال المعدنين المربوطين وايضا تم اكل لممدى الكمي لمظروف التشغيمية لظروف خمية قياس التيارات الكمفانية بينهما .تم قياس ودراسة جهود الت عينات مون خمية التركيز يسبب زيادة معدل التاكل لك التركيز.اظهرت النتائج انو في حالة استخدام التهوية فان ت المربوطة وفي تراكيز مختمفة لالوكسجين وممح كموريد الصوديوم بسبب التاثير الكمفاني. استخدام التهوية الحد اجزاء الخمية يسبب زيادة ممحوظة في معدل التاكل لمعينة المربوطة في الطرف االخر من الخمية نتيجة التاثير الكمفاني. زيادة درجة الحرارة يؤدي الى اتجاه غير مستقر في جهود التاكل الكمفانية والحرة وان زيادة درجة الحرارة يؤدي الى زيادة معدل التاكل الكمي لممعدنين . ي، معدل التآكل، خمية التركيز، التيار الكمفاني، درجة الحرارة، كموريدكاربونال فوالذال الكممات الدالة: ijcpe vol.11 no.1 (march 2010) iraqi journal of chemical and petroleum engineering vol.11 no.1 (march 2010) 11-19 issn: 1997-4884 minimization of toxic ions in waste water using emulsion liquid membrane technique adel a. al hemiri * and heaven e. mahmoud * chemical engineering department college of engineering university of baghdad – iraq abstract in the present study, the removal of zinc from synthetic waste water using emulsion liquid membrane extraction technique was investigated. synthetic surfactant solution is used as the emulsifying agent. diphenylthiocarbazon (ditizone) was used as the extracting agent dissolved in carbon tetrachloride as the organic solvent and sulfuric acid is used as the stripping agent. the parameters that influence the extraction percentage of zn +2 were studied. these are the ratio of volume of organic solvent to volume of aqueous feed (0.5-4), ratio of volume of surfactant solution to volume of aqueous feed (0.2-1.6), ph of the aqueous feed solution (5-10), mixing intensity (100-1000) rpm, concentration of extracting agent (20-400) ppm, surfactant concentration (0.2-2) wt.%, contact time (3-30) min, and concentration of strip phase (0.25-2) m . it was found that 87.4% of zn +2 can be removed from the aqueous feed solution at the optimum operating conditions. further studies were carried out on extraction percentages of other toxic metal ions (as +3 , hg +2 , pb +2 , cd +2 ) by using the same optimum conditions which were obtained for zinc ions except for the ph of the feed solutions. the ph values for best extraction percentages of arsenic, lead, and cadmium were (1, 10, 10) respectively. maximum extraction percentage of (98.5, 95.5 and 93.8) was obtained for arsenic, lead, and cadmium respectively, while mercury was completely removed from the aqueous feed solution within the acidic ph range. keywords: emulsion liquid membrane, waste water, removal of toxic ions, surfactant introduction the heightened concern for reduction of environmental pollution that has been occurring over the past 20 – 25 years has stimulated active continuing research on the toxicology of heavy metals. while the toxic effects of these substances is a widespread concern in the modern industrial context [1], many industries, such as the electroplating and mining companies, produce large amounts of mercury, lead, cadmium, silver, copper, and zinc ions. these industries are required by law to reduce the concentration of these toxic metals in their waste water before it is discharged into sewers, lakes, and streams [2]. virtually all metals can produce toxicity when ingested in sufficient quantities, but there are several which are especially important because either they are so pervasive, or produce toxicity at such low concentrations [1]. a broadly defined group of elements classified as heavy metals contain a number of members that are toxic. this toxicity may by virtue of their interaction with enzymes, their tendency to bind strongly with sulfhydryl (-sh) groups on proteins, or other in vivo effects [3] poses serious health risks to humans. this threat puts the scientific community under pressure to develop new methods to detect and eliminate toxic contaminants from wastewaters in efficient and economically viable ways [4]. removal of heavy metal ions from aqueous solutions has traditionally meant the precipitation of the ion, but this practice is now unpopular as it produces a sludge that has to be disposed in a landfill. electrochemical metal university of baghdad college of engineering iraqi journal of chemical and petroleum engineering minimization of toxic ions in waste water using emulsion liquid membrane technique 12 ijcpe vol.11 no.1 (march 2010) recovery is promising; however, waste streams are often dilute metals and have low plating efficiencies. solvent extraction of metals has been extensively used in hydrometallurgical operations [5], however the outlay of such equipment can be expensive, large volumes of organic extractants are required and the performance is often limited by hydrodynamic constraints such as flooding and entrainment [6]. since the invention of the liquid surfactant membrane by li (1968) the separation technique using liquid membranes has been noted as a novel method for separating and concentrating metal ions. the process is capable of giving higher degree of concentration of metal ion in fewer stages with maintaining the high selectivity of the solvent extraction [7]. liquid membrane extraction processes have certainly some attractive features like simple operation, high efficiency, extraction and stripping in one stage, larger interfacial area and scope of continuous operation [6]. an emulsion liquid membrane (elm) is a three-liquid-phase configuration consisting of two phases of the same nature (usually aqueous) separated by a third one, called the liquid membrane, immiscible with the other two. a typical system consists of a water-in-oil emulsion, stabilized by addition of a surfactant, dispersed in an aqueous solution in an agitated contactor. in either form, elms are used in separation processes in which a solute is extracted from the continuous phase into the liquid membrane, and from there into the emulsion droplets, by selective solubilization or by chemical reaction [8,9]. this study was set out to find the best operating conditions for the removal of the toxic ions: zn +2 , as +3 , hg +2 , pb +2 and cd +2 , using elm extraction for the purpose of waste water treatment. experimental work experimental and materials chemicals the chemicals used are carbon tertrachloride [ccl4], m.wt 153.82, dithizone [c13h12n4s], m.wt 256.33, sulfuric acid, m.wt 98.08, sodium bicarbonate [nahco3], m.wt 84.01, supplied by merck ltd. sodium hydroxide,[naoh], m.wt 40, zinc sulphate [znso4.7h2o], m.wt 287.54, , sodium chloride [nacl], m.wt 58.44, cadmium sulphate [3cdso4.8h2o], m.wt 769.56, lead dioxide [pbo2], m.wt 239.19, arsenous oxide[as2o3], m.wt 197.82, mercuric oxide [hgo], m.wt 216.59, sodium hexametaphosphate (napo3)6, m.wt 611.78, supplied by bdh chemicals. sodium carbonate [na2co3], m.wt 105.99, supplied by thomas baker ltd. sodium alkyl benzene sulphonate [ch3(ch2)noso3na], m.wt 288.38, and polyoxyethylene (o-ch2-ch2-o)10, m.wt 640, supplied by fluka. experimental procedure synthetic waste waters were prepared individually for each metal. specific amounts of metal ions were dissolved in distillated water to obtain the desired solution containing 90 ppm of the targeted metal ions. a green solution was obtained by dissolving a measured amount of the extracting agent (dithizone) in a certain volume of the organic phase of carbon tetrachloride. the volume of aqueous feed was taken as 50 ml. and the ratio of the organic phase to the feed phase was from 0.5 to 4, while that of the surfactant solution to the feed phase was from 0.2 to 1.6. the ph of the aqueous feed solution was adjusted by adding few drops of sodium hydroxide and/or sulfuric acid. a variable steady speed impeller with three blades was used for mixing in a two neck flask used as a container. the organic solvent which was lost during the mixing process due to volatility was recycled by using a condenser. the emulsion was prepared by emulsifying the aqueous solution of the strip phase (sulfuric acid or sodium hydroxide) with the organic phase (membrane phase) containing the carrier (extracting agent) with the aid of a mixer. when the metal ions were extracted from a basic surrounding sulfuric acid was used as the strip phase, while sodium hydroxide was used when the metal ions were extracted from an acidic surrounding. the strip solution of (sulfuric acid or sodium hydroxide) was added drop wise into the two neck flask containing the organic phase with the surfactant solution until 1:1 volume ratio was maintained for the organic phase to the internal phase. the solution was stirred continuously at a stirring speed 1000 rpm for 20 min. until a stable emulsion was formed. the prepared emulsion (organic phase and internal strip phase) was dispersed into the external aqueous feed phase of the waste water from which the targeted metal ions were to be extracted. the surfactant solution used as an emulsifying agent consists of all sodium cations with 50%wt. sodium hexametaphosphate, 10%wt. sodium alkyl benzene sulphonate as anionic surfactant and 0.5%wt. polyethylene as nonionic surfactant; it also contains 39.5% wt. sodium carbonate and sodium bicarbonate as ph buffering agents. as the system was agitated the targeted metal ions were transported to the interface between the emulsion and the feed phase where these metal ions reacts with the extracting (chelating) agent (hl) to form soluble metal complexes (mln). this may be represented by the following equations: organic phase aqueous phase adel a. al – hemiri and heaven e. mahmoud 13 ijcpe vol.11 no.1 (march 2010) the metal complex diffused to the interior of the emulsion droplet until it encountered a micro droplet of the internal phase where the metal ion was stripped by the stripping agent and trapped in the internal phase. the net effect was unidirectional mass transport of the cation (metal ion) from the original feed to the receiving phase with counter transport of hydrogen ions; after contacting the emulsion with the feed phase the dispersion was transported to a separator funnel where it was allowed to separate. the dispersion separated into three layers in the separator funnel. the upper layer contained the feed aqueous solution. the middle layer composed of the emulsion phase of the organic and the enriched internal phase by the metal ions trapped in it. finally the bottom layer composed of a very small portion of the organic solvent separated from the emulsion. the recovery of the solvent from the emulsion phase was carried out by applying a physical de-emulsification method including the addition of 0.3 m nacl which breaks the emulsion into two immiscible phases. the upper layer contained the concentrated strip solution with the targeted ions and the surfactant solution, while the bottom layer comprised of the organic phase containing the carrier (extracting agent). the experiments were carried out at 298 0 k and the sequence of operations is as shown schematically in figure1. atomic adsorption spectrophotometer (perkin elmer model 5000) was used to measure the concentration of all metal ions except for mercury where a uv-visible recording spectrometer (shimadzu model 160 a) was used [10]. figure1 schematic diagram of the operation minimization of toxic ions in waste water using emulsion liquid membrane technique 14 ijcpe vol.11 no.1 (march 2010) results and discussion the parameters that influence the extraction percentage of zn +2 were studied and are discussed here. these are, ratio of volume of organic solvent to volume of aqueous feed (0.5-4), ratio of volume of surfactant solution to volume of aqueous feed (0.2-1.6), ph of the aqueous feed solution (5-10), mixing intensity (100-1000) rpm, concentration of extracting agent (20-400) ppm, surfactant concentration (0.2-2) wt.%, contact time (3-30) min, and concentration of strip phase (0.25-2) m. the effect of ratio of volume of organic solvent to volume of aqueous feed figure 2 shows the effect of ratio of volume of organic solvent to volume of aqueous feed on extraction percentage of zinc ions when 20 ml of volume of surfactant, the ph of the feed solution adjusted at 7.3, concentration of surfactant 1.0 wt.% , mixing intensity 700 rpm, contact time of 5min., and concentration of strip solution 1m were used. it can be seen that the extraction percentage is low for relatively smaller volumes of solvent. as the relative volume of solvent increases the extraction percentage values increased until it reaches a maximum ratio at (2). the low values of extraction percentage are because when small volume of organic solvent is employed small volume of emulsion is obtained. therefore, the surface area of mass transfer will decrease due to the formation of a small number of emulsion globules. the increased ratios of organic solvent to aqueous feed also decrease the values of extraction percentage because the globules are close together, therefore, more likely to coalescence leading to a reduction in the total surface of mass transfer. 58 62 66 70 74 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 ratio of volume of organic solvent to volume of aqueous feed vorg/vaq e x tr a c ti o n p e rc e n ta g e % figure 2 effect of ratio of organic solvent to aqueous feed on the extraction percentage of zn +2 effect of ratio of volume of surfactant solution to volume of aqueous feed effect of ratio of volume of surfactant to volume of aqueous feed on the extraction percentage of zinc ions using ratio of organic solvent to aqueous feed of 2, ph of the feed solution 7.3, concentration of the extracting agent 250 ppm, concentration of surfactant 1.0 wt.% , mixing intensity 700 rpm, contact time of 5min., and concentration of strip solution 1m was investigated. as the volume of surfactant solution is related directly to the droplet size and membrane thickness, the extraction percentage depends on the relative volumes of surfactant solution and the feed. there is a minimum quantity of surfactant solution to obtain a stable emulsion. if the amount of surfactant solution is less than the minimum, the extraction percentage is low because the membrane breaking up reducing the interfacial area for mass transfer. it is expected that for large volumes of surfactant solution, extraction percentage does not change. figure 3 shows experimental results for this ratio. it can be seen that extraction percentage is constant when the volume ratio approximately 1.4 and this is the minimum amount of surfactant that should be added. effect of ph of the aqueous feed it is observed that the ph of the aqueous feed phase played an important role on the values of extraction percentage of the targeted zinc ions. this is shown in figure 4. the experimental conditions were kept constant at ratio of organic solvent to aqueous feed of 2, ratio of volume of surfactant solution to volume of aqueous feed of 1.4, concentration of the extracting agent 250 ppm, concentration of surfactant 1.0 wt.% , mixing intensity 700 rpm, contact time of 5min., and concentration of strip solution 1m. higher extraction percentage is obtained as ph was moved towards basic range. this is because the nature of the extracting agent which forms stronger complexes in this range of ph values. at low ph values there is a decrease in the extraction percentage due to the incomplete deprotonation of the extracting agent in the membrane interfaces of the feed phase, thereby decreasing the formation of metal-chelating agent complex. for this same reason the extraction percentage decreases in higher basic range. and it is clear from figure 4 that neutral conditions (ph around 7) gave the highest extraction rate. effect of mixing intensity figure 5 shows the effect of mixing intensity of emulsion on extraction percentage of zinc ions. the operating parameters were ratio of organic solvent to aqueous feed of 2, ratio of volume of surfactant solution to volume of aqueous feed of 1.4, ph of the feed solution 7.5, concentration of the extracting agent 250 ppm, concentration of surfactant 1.0 wt.% , contact time of 5min., and concentration of strip solution 1m. adel a. al – hemiri and heaven e. mahmoud 15 ijcpe vol.11 no.1 (march 2010) it can be seen that the extraction percentage increases with increasing mixing intensity up to 800 rpm where it becomes almost constant. this may be due to the fact that the droplets reach stable drop size that does not change at higher mixing intensity. at low mixing intensity some of the drops might breakup due to rupture of weak membrane; therefore, the extraction percentage decreases. but, when increasing the mixing intensity, gradually, the emulsion becomes more stable because drop diameters of the emulsion decrease. this results in improved permeation rate due to the increase in mass transfer area. however, further studies should be carried out to quantify the effect of the drop size and drop size distribution on the liquid membrane extraction. 60 64 68 72 76 80 84 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 ratio of volum e of surfactant to volum e of aqueous feed vs/vaq e x tr a c ti o n p e rc e n ta g e % figure 3 effect of ratio of volume of surfactant solution to volume of aqueous feed on the extraction percentage of zn +2 40 44 48 52 56 60 64 68 72 76 80 84 88 4 5 6 7 8 9 10 11 12 ph e x tr a c ti o n p e rc e n ta g e % figure 4 effect of ph on the extraction percentage of zn +2 50 54 58 62 66 70 74 78 82 86 0 200 400 600 800 1000 1200 mixing intensity(rpm ) e x tr a c ti o n p e rc e n ta g e e % figure 5 effect of mixing intensity on the extraction percentage of zn +2 effect of concentration of extracting agent it is obvious that the concentration of the extracting agent also plays an important role in emulsion liquid membrane (elm) extraction and on the extraction percentage of the targeted zinc ions. emulsion liquid membrane (elm) parameters were kept constant at ratio of organic solvent to aqueous feed of 2, ratio of volume of surfactant solution to volume of aqueous feed of 1.4, ph of the feed solution 7.5, mixing intensity 1000 rpm, concentration of surfactant 1.0 wt.% , contact time of 5min., and concentration of strip solution 1m. the effect of carrier (extracting agent) concentration on the extraction percentage is displayed in figure 6. the initial extraction percentage increased with the increase in the concentration of extractant, because there would be enough molecules of extractant in the membrane to complex with the zinc ions and carries these metal ions from one side of the membrane to the other side. however, it will be expected that at a very high content of extractant in the membrane the values of extraction percentage decreases. the increasing concentration of extractant promotes swelling of the emulsion, which dilutes the aqueous strip phase and decreases the efficiency of the process. also when increasing the concentration of the extractant maximum percentage of zinc ions remain in the complex form (in membrane phase) without getting stripped which in turn affected the final recovery by elm process. minimization of toxic ions in waste water using emulsion liquid membrane technique 16 ijcpe vol.11 no.1 (march 2010) 60 64 68 72 76 80 84 88 0 100 200 300 400 500 concentration of dithizone (ppm ) e x tr a c ti o n p e rc e n ta g e % figure 6 effect of extracting agent concentration on the extraction percentage of zn +2 effect of surfactant concentration effect of concentration of surfactant on the extraction percentage of zinc ions using ratio of organic solvent to aqueous feed of 2, ratio of volume of surfactant solution to volume of aqueous feed of 1.4, ph of the feed solution 7.5, concentration of the extracting agent 280 ppm, mixing intensity 1000 rpm, contact time of 5min., and concentration of strip solution 1m was investigated. as the surfactant concentration increases the values of extraction percentage also increases owing to the increasing in the emulsion stability, but a further increase in the surfactant concentration decreases the values of extraction percentage due to mass transfer resistance caused by surfactant film. also when the surfactant concentration increases the viscosity of the organic phase increases resulting in lowering the emulsion liquid membrane permeation, and diffusivity of complexes in the organic phase is reduced. therefore, the amount of the surfactant in the membrane must be minimal but it must be enough to stabilize the emulsion. the effect of concentration of surfactant is showed in the figure 7. 60 64 68 72 76 80 84 88 0 0.4 0.8 1.2 1.6 2 2.4 sufactant concentration w t% e x tr a c ti o n p e rc e n ta g e % figure 7 effect of concentration of surfactant on the extraction percentage of zn +2 effect of contact time figure 8 shows the effect of contact time on extraction percentage of zinc ions. the operating parameters were ratio of organic solvent to aqueous feed of 2, ratio of volume of surfactant solution to volume of aqueous feed of 1.4, ph of the feed solution 7.5, concentration of the extracting agent 280 ppm, mixing intensity 1000 rpm, concentration of surfactant 1.0 wt.% , and concentration of strip solution 1m. it is observed from the figure that extraction percentage increases with the increase of contact time between the emulsion and the external feed phase until it reaches a maximum value then starts to decrease. at short contact time low values of extraction percentage are obtained. this is because the contact between the external feed phase and the emulsion was not enough to complex zinc ions with the complexing agents to extract them into the membrane phase; thereby the concentration of zinc ions in the external phase remains high. as the contact time increases, the ph of the aqueous feed solution will continue to decrease below the value which promotes the complexation reaction between the metal ions and the complex agents. this is due to the influx of hydrogen ions carried across the membrane from within the emulsion thus increasing water transfer into the internal phase causing the membrane to swell and initiates breakage of the emulsion. this results in the leakage of zinc ions from the internal phase to the external feed, thus decreasing the extraction rate. 78 82 86 90 0 5 10 15 20 25 30 35 contact tim e (m in.) e x tr a c ti o n p e rc e n ta g e % figure 8 effect of contact time on the extraction percentage of zn +2 effect of stripping phase concentration effect of stripping phase concentration on the extraction percentage of zinc ions using ratio of organic solvent to aqueous feed of 2, ratio of volume of surfactant solution to volume of aqueous feed of 1.4, ph of the feed solution 7.5, concentration of the extracting agent 280 ppm, adel a. al – hemiri and heaven e. mahmoud 17 ijcpe vol.11 no.1 (march 2010) mixing intensity 1000 rpm, concentration of surfactant 1.0 wt. %, contact time of 10 min. was studied. it is obvious from figure 9 that the extraction percentage increases with increasing the stripping phase concentration. this is owing to the increase in the capacity of the internal phase. however, for high concentration of the stripping agent the extraction percentage of the targeted zinc ions decreases. this is due to swelling of the emulsion by water transport to the internal phase, thus diluting it and decreasing the emulsion stability. 60 64 68 72 76 80 84 88 92 0 0.25 0.5 0.75 1 1.25 1.5 1.75 2 2.25 concentration of stripping phase (m) e x t r a c t io n p e r c e n t a g e % figure 9 effect of stripping phase concentration on the extraction percentage of zn +2 further studies as the chelating reaction between the chelating agent and the metal ions is very important intermediate step in the emulsion liquid membrane technique which is responsible for the transfer of the metal ion from the external aqueous feed phase to the internal aqueous phase, the effect of ph was investigated for other toxic metal ions (as +3 , hg +2 , pb +2 , cd +2 ). this is done since the nature of the chelating agent (dithizone) is very sensitive to ph values, where it reacts with every metal ion in a definite range of ph values. the same optimum parameters which were obtained for zinc ions (i.e., ratio of volume of organic solvent to volume of aqueous feed of 2, volume of surfactant solution to volume of aqueous feed of 1.4, mixing intensity 1000 rpm, concentration of the extracting agent 280 ppm, surfactant concentration 1wt. %, contact time of 10 min., and concentration of strip phase 1 m) were used for these metal ions since they only affect the effectiveness of the emulsion liquid membrane operation. the effect of ph on extraction for these ions is shown in figure 10. it is obvious that the ph values of the feed solution slightly affect the extraction percentage of arsenic, however higher extraction percentage is obtained in very high acidic surroundings. this is due to the fact that arsenic possess an ion pair, the nature of which enables it to take part in the chelation reactions and even some of its compounds are used as ion association chelating agents. it can be seen from this figure that varying the values of ph has no effect on the extraction of hg ions. this is due to the range of ph values used which is the optimum for the complexing reaction between mercury ions and the chelating agent (dithizone) and very strong metal complexes are formed, thus the metal complexes remain in the membrane phase and it is very difficult to be stripped. this resulted in that the mercury ions are completely removed from the aqueous feed solution and extraction percentage values attend unity. it is observed that the ph of the aqueous feed phase played an important role on the values of extraction percentage of lead ions. as shown in the above mentioned figure higher extraction percentage is obtained as ph was moved towards more basic range up to a maximum value then it started to decrease. this was due to the nature of the extracting agent which forms strong complexes in this range of ph values. at low ph values there is a decrease in the extraction percentage due to the incomplete deprotonation of the extracting agent in the membrane interfaces of the feed phase, thereby decreasing the formation of metal-chelating agent complex. in very high basic surrounding a significant decrease is observed of the extraction percentage of lead ions. this is due to the nature of the extracting agent which prefers moderate basic surrounding in order to complex with the targeted lead ions. higher extraction percentage is obtained as ph was moved towards more basic range up to a maximum value then it started to decrease. this is because the nature of the extracting agent which forms strong complexes with the metals in this range of ph values. at low ph values there is a decrease in the extraction percentage due to the incomplete deprotonation of the extracting agent in the membrane interfaces of the feed phase, thereby decreasing the formation of metal-chelating agent complex. at high ph values there is a slight decrease in extraction percentage this is because of the complexation of the chelating agent with the targeted cadmium ions in a wide range of basic surrounding. minimization of toxic ions in waste water using emulsion liquid membrane technique 18 ijcpe vol.11 no.1 (march 2010) 72 76 80 84 88 92 96 100 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 ph e x tr a c ti o n p e r c e n ta g e % arsenic mercury lead cadmium figure 10 effect of ph on extraction percentage of some toxic metal ions conclusions for the removal of zn +2 , the following conclusions are arrived at: 1. the increase in ratio of volume of organic solvent to aqueous feed caused an increase in extraction percentage up to ratio 2, and then the extraction percentage started to decrease with the increase of the ratio. 2. the extraction percentage increases as the ratio of volume of surfactant solution to volume of aqueous feed increased up to ratio 1.4, then the extraction percentage is essentially constant. 3. as ph of the aqueous feed increased the extraction percentage also increased up to ph value of 7.5, then the extraction percentage started to decrease with the increase in the ph value of the aqueous feed. 4. the increase in mixing intensity caused an increase in extraction percentage up to 1000 rpm, and then the extraction percentage is approximately constant. 5. the increase in extracting agent concentration caused an increase in extraction percentage up to 280 ppm, and then the extraction percentage started to decrease with the increase in the extracting agent amount. 6. as the surfactant concentration increased the extraction percentage increased up to concentration of 1.0 wt %, then the extraction percentage decreases with the increase in surfactant concentration. 7. the extraction percentage increases as contact time increased up to about 10 min., and then the extraction percentage decreases with increasing time of contact. 8. the increase in the concentration of internal aqueous phase caused an increase in the extraction percentage up to concentration of 1 m, and then the extraction percentage started to decrease with the increase of the concentration of internal aqueous phase. for the other ions the conclusion is: as ph of the aqueous feed increased the extraction percentage of both lead and cadmium also increased up to ph value of 10, then the extraction percentage started to decrease with the increase in the ph value of the aqueous feed. while for arsenic, as the ph values increased the extraction percentage is slightly decreased, maximum value of extraction percentage was achieved at ph value of 1. and the extraction of mercury was not effected by the change in ph of the aqueous feed in the examined ph range, and the extraction percentage is close to unity. references 1. theodore b. hoekman, “heavy metal toxicology”, http://www.hbci.com/~wenonah/hydro/heavmet.htm. 5/12/2007. 2. warren h. philipp, jr. and kenneth w. street, jr., “a new martial for removing metals from water” http://www.p2 pays.org/ref%5co2/01107.pdf, 25/7/2007. 3. d. max roundhill (2001) “extraction of metals from soils and waters”, springer, http://books.google.com/books, 12/6/2007. 4. rey juan carlos (2007) “new wastewater treatment system removes heavy metals”,sciencedaily, http://www.sciencedaily.com/releases/2007/10/0710 20110548.htm, 12/6/2007. 5. bhavani raghuraman, neena trmizi, and john wienick (1994) “emulsion liquid membrane for waste water treatment”, environ. sci. technol., vol.28, p.p. (1090-1098), http://pubs.acs.org.connector.ivsl.org/cgibin/arichive.cgi 12/6/2007. 6. norasikin othman, masahiro goto, hanapi mat (2000) “liquid membrane technology for precious metal recovery from industrial waste”, engineering university technology malaysia, http://www.science direct.com.connector.ivsl.org/science, 25/7/2007. 7. masahiro goto, takahiko kakoi, naoya yoshii, kazuo kondo, and fumiyuki nakashio (1993) “ effect of synthesized surfactants in the separation of rare earth metals by liquid surfactant membrane”, ind. eng. chem. res., vol. 32, p.p.(1681-1685), published by american chemical society, http://pubs.acs.org.connector.ivsl.org/cgibin/arichive.cgi, 11/8/2007. http://www.hbci.com/~wenonah/hydro/heavmet.htm http://www/ http://books.google.com/books http://www.sciencedaily.com/releases/2007/10/071020110548.htm http://www.sciencedaily.com/releases/2007/10/071020110548.htm http://pubs.acs.org.connector.ivsl.org/cgi-bin/arichive.cgi%2012/6/2007 http://pubs.acs.org.connector.ivsl.org/cgi-bin/arichive.cgi%2012/6/2007 http://www.science/ http://pubs.acs.org.connector.ivsl.org/cgi-bin/arichive.cgi http://pubs.acs.org.connector.ivsl.org/cgi-bin/arichive.cgi adel a. al – hemiri and heaven e. mahmoud 19 ijcpe vol.11 no.1 (march 2010) 8. josefine de gyves and edwardo rodriguez de san miguel (1999) “metal ion separation by supported liquid membranes”, ind. eng. chem. res., vol.38, p.p. (2182-2202), published by american chemical society, http://pubs.acs.org.connector.ivsl.org/cgibin/arichive.cgi, 11/8/2007. 9. tatiana gallego-lizon and e. susana perez de ortiz (2000) “drop sizes in liquid membrane dispersion”, ind. eng. chem. res., vol.39, p.p. (5020-5026), published by american chemical society, http://pubs.acs.org.connector.ivsl.org/cgibin/arichive.cgi, 11/8/2007. 10. mahmoud, h. e., (oct./2007) “minimization of toxic ions in waste water using emulsion liquid membrane technique”, m.sc. thesis,chem.eng.dept., baghdad university. http://pubs.acs.org.connector.ivsl.org/cgi-bin/arichive.cgi http://pubs.acs.org.connector.ivsl.org/cgi-bin/arichive.cgi http://pubs.acs.org.connector.ivsl.org/cgi-bin/arichive.cgi http://pubs.acs.org.connector.ivsl.org/cgi-bin/arichive.cgi available online at https://ijcpe.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.19 no.1 (march 2018) 1 – 12 issn: 1997-4884 corresponding authors: samar k. theydan, e-mail: samarkarim26@yahoo.com iraqi journal of chemical and petroleum engineering effect of process variables, adsorption kinetics and equilibrium studies of hexavalent chromium removal from aqueous solution by date seeds and its activated carbon by zncl2 samar k. theydan chemical engineering department-college of engineering-university of baghdad-iraq abstract the adsorption of hexavalent chromium by preparing activated carbon from date seeds with zinc chloride as chemical activator and granular date seeds was studied in a batch system. the characteristics of date seeds and prepared activated carbon (zac) were determined and found to have a surface area 500.01 m 2 /g and 1050.01 m 2 /g , respectively and iodine number of 485.78 mg/g and 1012.91 mg/g, respectively. the effects of ph value (2-12), initial sorbate concentration(50-450mg/l), adsorbent weight (0.004-0.036g) and contact time (30-150 min) on the adsorption process were studied . for cr(vi) adsorption on zac, at 120 min time contact, ph solution 2 and 0.02 adsorbent weight will achieve an amount of 35.6 mg/g adsorbed . while when use date seeds as adsorbent , conditions of 3 solution ph, 0.02 absorbent weight , and 120 contact time gave 26.49 mg/g adsorbed amount. using both langmuir, freundlich and sips models were explain the dsorption isotherms. it declare that the sips model fits well with the experimental data with a maximum cr( vi) adsorption capacity for (zac) and granular date stone 233.493 and 208.055 mg/g, respectively . the kinetics data which obtained at different initial cr(vi) concentrations were examined by using pseudo-first-order, pseudo-second-order, and intra-particle diffusion models . the result gained showed that the second-order model was only describing well the empirical kinetics data of both (zac) and granular date seeds. it was noticed that the granular date seeds has adsorption performance lower than the (zac). keywords: activated carbon, chemical activation, zinc chloride, date seeds, chromium ion, kinetics, isotherm, adsorption. 1introduction the heavy metal ions presence in natural by the activity of volcanic and weathering of rocks and it can be found in a variety of industries, their potential impact is a major concern for a many research in environmental science due to their toxicity to many life forms [1]. chromium ion is one of the contaminants which exist in hexavalent and trivalent forms [2]. trivalent chromium is an essential element in humans and is much less toxic than the hexavalent one [3]. overexposure to cr(vi) causes cancer in the digestive tract and irritation and corrosion of the skin and, probably, to lung carcinoma and may cause epigastric pain, nausea, vomiting, severe diarrhea and hemorrhage [4]. before wastewater transport and cycling into the natural environment, it is therefore fundamental to abstraction cr(vi) from wastewater. chemical and physical processes such like electrochemical precipitation, ion exchange, chemical precipitation, adsorption, ultra-filtration, electro-dialysis and reverse osmosis are available for the reduction of cr(vi) concentration in wastewater [5-9] . toxic sludge generation, incomplete metal elimination and high cost are the main defects of these processes. the minimal cost treatment option had selected to the activated carbon adsorption, especially in processing low concentration of the wastewater streams and in meeting rigid level of treatment [1]. the black solid activated carbon substance similar to granular or powder charcoal and are carbonaceous material that have highly developed porosity, internal surface area and relatively high mechanical strength [10]. removing a large variety of the toxic pollutants due to high removal efficiency in the activated carbon based system promoted the activated carbon adsorption to be widely attractive chosen in the treatment of chromium containing wastewaters [11-13]. commercial activated carbons are very expensive, therefore it can be developed from low cost materials such as agricultural waste products, biomass and various solid substances [14-17]. agricultural biomasses mainly consist of lignin, cellulose, hemi-cellulose and some proteins. various low cost adsorbent from agricultural wastes were used in multi research workers like as coconut coirpith, saw dust, rice husk, banana pith, cottonseed hulls, apple wastes, sugarcane bagasse pith, peanut hull [18]. samar k. theydan / iraqi journal of chemical and petroleum engineering91,9 (2018) 9-12 2 the production of activated carbon from dates’ seeds were concentrated mostly on the development of the high quality activated carbon [19] . activated carbon were prepared from two processes; physical activation processes, this process is usually carried out in two stages. the first stage is the carbonization stage to eliminate the bulk of the volatile matter and this achieved by using steam, nitrogen or carbon dioxide which used for mild oxidation followed by an activation stage to develop the porosity and surface area[20 , 21] . chemical activation processes in which the raw material is impregnated with activating agents such as h2so4 , h3po4 , zncl2 , and kcl; then heated at different temperatures [22-26] .chemical activation by zinc chloride improves the pore development in the carbon structure, and because of the effect of chemicals, the yields of carbon are usually high [27]. the main objective of this research is to uptake toxic chromium ion from different solutions concentration by developing a new type of activated carbon from date palm seed activated with zinc chloride and date seeds itself. to estimate the maximum adsorption capacity of the toxic chromium ion, it has been used a batch adsorption process, and study the effect of process variables. six mathematical models were also tested: the langmuir’s, freundlich’s and sips's models for sorption isotherms, and first and second-order rate and intra-particle equations for description of kinetic. 2experimental work 2.1. materials in the preparation of activated carbon, date seeds were applied as a biomass. to get rid of impurities of the date seeds, the seeds were first washed with water, dried at 110 ˚c for 24 h, for the preparation of activated carbon it has been selected fraction of particle sizes between 1 and 3 mm for this purpose the date seeds crushed using disk mill, and sieved. as dehydrating chemical reagent for activation of date seeds we used zinc chloride (purchased from didactic company) of purity 99.9%. a stock solution of cr(vi) was prepared (1000 mg/l) by dissolving desired amount of potassium dichromate (k2cr2o7) in distilled water and to obtain total chromium concentration levels ranging from 50 to 450 mg/l the stock solution was diluted with distilled water . hydrochloric acid, sodium thiosulfate, and iodine all these chemical were used for analytical grades. 2.2. experimental procedure of activated carbon the dried raw material weighting 10 g was well mixed with 100 ml of zncl2 solution of impregnation ratio (weight of activating agent/weight of dried seeds) 1.25 g/g at room temperature for 24 h. for completely dried the impregnated samples were dried at 110 ˚c and after that the samples were stocks in a desiccator. a stainless steel reactor (2.5 cm diameter x 10 cm length) which it had a removable cover with 2 mm and to allow the escape of the pyrolysis gases for this purpose the reactor has a hole at the center of that cover, the reactor other end was closed. the reactor was placed in a furnace and heated to carbonization the dried impregnated samples at constant rate of 10 ˚c /min and held at carbonized temperature 500˚c for carbonization time 2 h. to allow the carbonized samples to be cool after the end of activation time they were withdrawn from the furnace. following that, the samples were placed with 0.1 m hcl solution, the liquid to solid ratio will kept 10 ml/g. the mixtures were left overnight at room temperature, and then filtered and washed the samples repeatedly with distilled water until the ph of filtrate reached 6.5-7 [28].following that , the samples were dried at 110 ˚c for 24 h, to calculate the yield of the activated carbon that produce it will be weighted . at last the samples were stocked in hermetic bottles. to determine the yield of activated carbon, it was used the following equation: 100 x w w (%) yield o f  (1) where wf and wo are the final dry weight activated carbon samples (g) and the dry weight of raw material (g), respectively. 2.3. adsorbents characteristics selected physical, chemical and adsorption properties were used to characterize the adsorbents such these properties like bulk density, surface area, ash content, ph, conductivity, iodine number and maximum cr uptake. the specifics of the characterization methods were illustrated as follows: bulk density is a measurement of the weight of substance that can be included in a given volume under fixed conditions, it was calculated according to procedure that reported by ahmedna et al. [29]. moisture content was calculated for the adsorbent samples using oven drying method as has been illustrated by adekola and adegoke [30]. ash content of the adsorbent samples is the remnant that remains when the carbonaceous portion is burned off [31]. iodine number which is defined as the one gram of adsorbent samples adsorbed milligrams of iodine , the micropore content(0 to 20 å) of adsorbent samples were measured by adsorption of iodine from solution,it was calculate by standard methods[32] . surface area was estimated by applying of bet equation to the adsorption– desorption isotherm of n2 at 77 k [33]. novawin2 data analysis software was used to perform these calculations [34]. the morphology of prepared activated and raw material was examined by scanning electron microscopy (sem) (300 k pixel cmos). samar k. theydan / iraqi journal of chemical and petroleum engineering91,9 (2018) 9-12 3 the concentrations of cr(vi) ion was estimated calorimetrically. the maximum wavelength for absorbance at which the absorbance values of cr(vi) will be measured was (λ max = 540 nm) by making the color of cr(vi) solution a purple-violet color with 1,5diphenylcarbazide in the acidic condition. this was performed by dissolving 0.25 g 1,5diphenylcarbazide in 50 ml acetone stock in a brown bottle discard when the solution becomes discolored ,transfer 95 ml of the cr(vi) solution to be to a 100 ml volumetric flask , add 2 ml diphenylcarbazide solution and mix , add h2so4 solution to give a ph of 2 ± 0.5 , dilute to 100 ml with reagent water , and let stand 5 to 10 min for full color development and measured its absorbance [35]. 2.4. adsorption isotherms the adsorption experiments of hexavalent chromium were executed in order to calculate the maximum adsorptive capacity of the prepared activated carbon and date seeds and this done by using 100 ml erlenmeyer flasks. in each flask a volume of 20 ml of cr(vi) solution with initial concentrations of 50–450 mg/l for cr(vi) where put in the flask. by adding 0.1 m hcl solution the ph of the solutions was achieved to 2 . in the each flask ,adding 0.02 g of the prepared activated carbon and date seeds , with average particle size of 250 μm, and hold in a shaker (type tr-1, germany) at 120 rpm for 4.5 h for cr(vi) solution to reach the equilibrium. after that samples were filtered before the concentrations of cr(vi) were analyzed by using uv visible spectrophotometer (shimadzu uv-160a) at maximum wave length 450 nm for cr(vi) . the cr(vi) final concentration at equilibrium, qe (mg/g), was determent by the following equation: w v ) c (c q e o e  (2) where co and ce are initial and equilibrium concentrations of the cr(vi) (mg/l), respectively, v is the volume of the aqueous cr(vi) solution (l), and w is the weight of adsorbents used (g). equilibrium adsorption of cr(vi) on the prepared activated carbon and date seeds was applied be fitting the experimental adsorption data by using the most widely isotherm equations , were these equation named the langmuir[36], freundlich[37] and sips [38]. these isotherm equations can be written as: c1 c k lq q e e l e k l  (3) (4) c 1/m eks1 c 1/m eks q q s e   (5) for the langmuir isotherm, an equilibrium parameter, rl, is the essential characteristics of this isotherm, which can expressed as follows [39]: k l1 1 r l c o  (6) where ql (mg/g) is the maximum adsorption capacity of zac and date seeds , the langmuir constant related to rate of adsorption is represent by kl (l/mg) ,the freundlich constants are kf((mg/g) (l/mg)1/n) which give an idea about the adsorption capacity and n which represent the adsorption intensity, the sips maximum uptake of cr(vi) per unit mass of date stone and zac is represent by qs (mg/g) is, sips constant ks((l/mg)1/m) which related to energy of adsorption , and constant m could be considered as the sips constant characterizing the heterogeneous of system. co is the highest initial solute concentration and where rl is the type of isothermal, if when rl equal to zero that mean the isotherm is reversible ,and when rl greater than zero and less than 1,the isotherm is preferable ,and the isotherm is linear rl equal to 1 , or not preferable when rl greater than 1. to analysis experimental data, it has been used the least-squares retreat program according to hooke-jeevesand gaussnewton method. the parameters in each equation and harmonization between the experimental and determent data can be obtained by using this type of program in terms of correlation coefficient r 2 . 2.5. adsorption kinetics adsorption kinetics provides valuable information about the reaction pathways and mechanism of the reaction. the kinetic experimental was done by employing a batch technique to study the effect of contact time and the uptake concentration of cr(vi) adsorption. the aqueous samples were taken at preset time intervals, and the concentrations of cr(vi) were similarly measured. the diffusion steps that normally controlled any adsorption process are : (i) the solute will transfer to the film surrounding the adsorbent from the bulk solution , (ii) then the solute will transfer to the adsorbent from the film , (iii) at last the solute will transport to the internal sites from the surface followed by attaching of the metal ions to the active sites. the overall rate of the adsorption process will be determined by the slowest steps and usually it is considered that the step (ii) leads to the adsorption of the surface and the step (iii) leads to the adsorption in the intra-particle [2]. a qt (mg/g) is the amount of cr(vi) that adsorbed at time t , was estimated depending on the concentration of cr(vi) at time t using samar k. theydan / iraqi journal of chemical and petroleum engineering91,9 (2018) 9-12 4 eq. (1). pseudo first-order model [40], pseudo-secondorder model [41], and intraparticle diffusion model [42] were used to analyze the kinetic data. these models can be shown by the following equations: pseudo-first-order model – (7) pseudo-second-order model qe t k 2 1 q t t  qe (8) intraparticle diffusion model (9) where qe and qt (mg/g) are the amount adsorbed of cr(vi) at equilibrium and at time t (min), respectively, k1 (1/min) is the adsorption rate constant, the rate constant of second-order equation is k2 that has a unit (g/mg min) , the intraparticle diffusion rate constant is k3 that has a unit (mg/g min 1/2 ) , constant that gives the idea about boundary layer thickness presented by c that has a unit (mg/g) . the application of kinetics models was shown by adopting the value of correlation coefficient r 2 . 3results and discussion 3.1. yield and characteristics in table (1) the yield and characteristics of zac and date seeds were determined and summarized. this table shows 43.23% yield of zac which was higher than that reported by k. suresh et al. [43] who found that 14.8 % yield could be obtained from date palm seed by co2 activation. fig. 1. sem micrographs (300x) of date seeds(a) and zac(b) table1. characteristics of zac and dates seeds characteristic zac date seeds yield(%) 43.23 bulk density (g/ml) 0.342 0.340 surface area (m 2 /g) 1050.01 500.03 ash content (%) 2.04 1.66 moisture content (%) 13.86 7.80 ph 6.1 4 conductivity (µs/m) 320 iodine number (mg/g) 1012.91 485.78 the surface area and iodine numbers are consider the most important characteristics, the surface area of zac is 1050.01 m 2 /g and for date seeds is 500.03 m 2 /g as has been shown in table (1). attia a. a. et al [5] showed that the prepared activated carbon that activated with sulphuric acid onto olive seeds has a surface area 448 m 2 /g. because of higher activity of zinc chloride which make an activated carbon with high pore , it can be noted from table (1) that iodine number of activated carbon was higher than that of date seeds, which mean zac has a micropore content greater than date seeds. the high surface area for an agricultural waste biomass enables date seeds to be used successively for removal of cr from aqueous solutions. haimour and emeish [44] showed that the iodine numbers activated carbon prepared by chemical activation of date seeds using phosphoric acid , was 485.78 mg/g and this result is less than that obtained in this study for zac. the capability of date seeds to remove most of chromium ion and that because of the high iodine number of date seeds which is a measure of micropore content (0 to 20 å), where the cr(vi) ion have molecular sizes in the range of micropores content. the sem images for the prepared activated carbon and date seeds were shown in fig. (1) .it can be notice from fig. (1a), that the date seeds have a very smooth surface and have very few pores on its surface. fig.(1b) shown the surface of the prepared activated carbon which activate with zncl2 , it can been seen become rough and many pores appear on the surface , and that become after zncl2 impregnation and activation at activation temperature 500 ◦c, impregnation ratio 1.25 g/g and activation time 2 h ,the reason for that the zncl2 impregnation had important effect on the increase in specific surface area and expansion of micropores . 3.2. effect of process variables in order to study the effect of solution ph (2-12), contact time (30-150 min.), and adsorbent weight (0.0040.036 g) on adsorbed amount and removal percentage of cr(vi) onto zac and date seeds, a set of experiments was carried out. a. effect of solution ph the ph of the solution has an effect on the adsorbent's charge density and the metallic species, so that the solution ph is consider one of the most parameters that have an influence on the metals ion adsorption [2]. samar k. theydan / iraqi journal of chemical and petroleum engineering91,9 (2018) 9-12 5 the charge of the surface might be positive or negative. a large number of surface functional groups were in the pore wall of activated carbon. the of cr(vi) adsorption depend on the solution ph can largely be related to the functional groups type and its ionic state and also on the chemistry of adsorbate in the solution[11]. the effect of ph on cr(vi) adsorption was studied over a ph range of 2–12 on zac and date seeds samples at 50 mg/l initial concentration ,adsorbent weight 0.02 g , solution volume 20 ml and contact time 120 min as shown in fig. 2.where fig. 2 represent the prepared activated carbons and date seeds data ,it can been seen that the effectiveness of the adsorbents occur in the acidic range and maximum uptake occurred at ph 2 for zac and ph 3 for date seeds . the adsorption increases from 6.25 mg/g to 26.49 mg/g for date seeds and 9.5 mg/g to 35.6 mg/g for zac of ph from 12 to 2.when the ph was raised from 2.0 to 7.0 the capacity of the adsorption has a sharp decrease and in basic range the effect became negligible, due to high electrostatic force of attraction the higher adsorption became in the lower ph ranges. the most ionic forms that cr(vi) may be exist in aqueous solutions are (hcro4 , cr2o7 -2 , cro4 -2 ) and the ph has in effect on the stability of these ions in aqueous systems [45]. the diffusion of chromate ions increase into the bulk of the adsorbent depend on the lowering the solution ph which increase number of h+ ions ,and thereby the negative charge on adsorbent surface will be neutralize [46]. the mostly form of cr(vi) adsorbed on the surface of activated carbon was hcro4 ions, it is well known that the ph between 1.0 and 4.0,the hcro4 ion was the stabile form of chromate ions [45]. the ph increase will be decrease adsorption amount and that because of increase the number of oh ions in the bulk which obstruct the diffusion of cr(vi) ions. and that agree with other investigators have also been reported that [47-51] they found that the optimum ph value was in the range 2-3 for the removal of cr(vi) from aqueous solutions. fig. 2. effect of solution ph on adsorbed amount b. effect of adsorbent dose as shown in fig.(3) the effect of sorbent dosages on the adsorption amount of chromium ion by both zac and date seeds on the ph 2 and 3 for zac and date seeds ,respectively , time 120 min , the zac and date seeds mass were varied from 0.004 to 0.036 g/ 20 ml, initial concentration of chromium ion 50 mg/l . as has been shown from fig.(3) that the date seeds and the prepared activated carbons followed the predicted pattern of decreasing adsorption amount as the dosage was increased and reaches a saturation level at high doses for both date seeds and prepared activated carbon this is probably because of the resistance to mass transfer of cr(vi) from bulk liquid to the surface of the solid .the adsorption decreasing from 52 mg/g to 14.22 mg/g for date seeds and from 75 to 16.99 mg/g for zac of adsorbent dosages 0.004 to 0.036 g/20 ml. increasing adsorption with dose can be attributed also to the increase in surface area and the availability of more adsorption sites and which was noticed by a. a. attia et al.[5]. fig. 3. effect of adsorbent weight on adsorbed amount c. effect of contact time the amount of cr(vi) adsorbed on date seeds and zac was studied as a function of the mixing time at initial concentration of 50 mg/l of cr(vi) at 0.02 g of adsorbent and the desired ph . the results are given in fig. (4). it is clear from this figure that the adsorption of cr(vi) increased with increase in contact time from 30 to 150 min ,for date seeds the adsorption amount increase from 15.778 mg/g to 27.216 mg/g and for zac 24.692 mg/g to 36.442 mg/g , then became slow up to 150 min and no change in the adsorption amount was observed with further increase the contact time up to 24 h in the case of both date seeds and zac samples. the equilibrium time by the nature and compactness of the adsorbents. fig. 4. effect of contact time on adsorbed amount samar k. theydan / iraqi journal of chemical and petroleum engineering91,9 (2018) 9-12 6 3.3. adsorption isotherms langmuir, freundlich and sips isotherms, eqs. (3,4)– (5) are fitted with the experimental equilibrium data for cr(vi) adsorption on zac and date seeds that calculated from eq. (2). table (2) presented the calculated constants of the three isotherm equations along with r 2 values. this table shows that the sips isotherm had the best correlation coefficient with r 2 values 0.9999 and 0.999 for adsorption of cr(vi) on zac and date seeds , respectively that because the sips isotherm has ability to predict wide ranges of adsorbate concentration. when correlate experimental adsorption data at was found that the sips isotherm as compared with langmuir and freundlich isotherms has a successful application with the three parameters[ 52,53 ]. in fig.( 5) sips isotherm was using to correlate the experimental data . it can been seen from this figure that when using zac the adsorbed amount of cr(vi) increases. the table (2) , showed the langmuir isotherm, the values of rl are 0.0297 and 0.1387 of zac and the date seeds , respectively, if the average of the rl values for each of the different initial concentrations used is between 0 and 1 [54] it indicates favorable adsorption of cr(vi) adsorption on zac and date seeds. it can been seen from table (2) that the fitting results of freundlich model has a predict to favorability of adsorption when the value of (1/n) less than one, that will be represent a favorable adsorption condition [55,56] and that agree with the results obtained where the magnitude of the exponent, (1/n) 0.266 and 0.435 of zac and date seeds, respectively. the results of table( 2) show that the data which fitted to the and isotherms showed the correlated coefficient values r 2 for langmuir higher than that of freundlich isotherms, which approve the monolayer adsorption. in this study, table (2) shows the maximum cr(vi) adsorption capacity of 233.493 and 208.055 for zac and date seeds , respectively , as has been calculated from sips isotherm fitting. table (3) compared the maximum adsorption of cr(vi) that obtained in this study to those obtained in the literature for activated carbons prepared from various agricultural wastes. it can be seen from this table that the prepared activated carbon can be classified as one of the effective adsorbents for this purpose. table 2. adsorption isotherm parameters for cr(vi) on zac and date seeds sample freundlich isotherm ks((mg/g) (l/mg) 1/n 1/n r 2 zac gds 52.021 15.456 0.266 0-435 0.968 0.989 sample sipes isotherm qs(mg/g) ks((l/mg) 1/m ) m r 2 zac gds 233.493 208.055 0.1008 0.1818 1.2178 0.9462 0.9999 0.9998 sample langmuir isotherm qm(mg/g) kl(l/mg) rl r 2 zac gds 218.77 215.43 0.0726 0.0138 0.0297 0.1387 0.997 0.9998 fig. 5. equilibrium isotherm of cr(vi) adsorption on zac and date seeds samples correlated with sips equation (cr(vi) conc., 50–450 mg/l; volume of cr(vi) solution, 20 ml; amount of activated carbon, 0.02 g; ph, 2 and 3for zac and date steeds respectively ; contact time, 5.5 h) table 3. comparison of cr(iv) maximum adsorption capacity onto activated carbon prepared from various precursors activated carbon activator maximum capacity (mg/g) ref. olive bagasse-carbon physical activation of steam 88.59 [2] olive stones-carbon sulfuric acid 71 [5] wood-carbon koh 180.3 [57] hazelnut shell -carbon h2s04 52.2 [58] date stones-carbon sulfuric acid 120.48 [59] tamarind wood carbon zncl2 28.019 [10] date seeds-carbon zncl2 233.493 present study 3.4. kinetics of adsorption the influence of contact time on adsorption capacity of zac and date seeds for different initial concentrations of cr(vi) illustrated in fig.(6) and fig.(7) .when time increase the adsorption capacity for cr(vi) increase and that shown in these figures , and about 4.5 h the adsorption attained equilibrium . an adsorption capacity for zac and date stone, respectively of 210,65 and 170,03 mg/g is obtained at 4.5 h contact time, 450 mg/l initial cr concentration, 2 ph value and 0.02/20 ml adsorbent dose. these figures also show that when increasing initial concentration the amount of cr(vi) adsorbed, qe (mg/g), increase . moreover the adsorption was quick at the initial stages and dropped gradually after the equilibrium point till it reach almost constant. the removal of cr(vi) will become independent of initial concentrations and that because of the available surface to initial cr(vi) concentration ratio was larger at low concentrations , but the adsorption capacity will depend samar k. theydan / iraqi journal of chemical and petroleum engineering91,9 (2018) 9-12 7 upon the initial concentration in the case of higher concentrations, because this ratio was low. the possible of monolayer coverage for cr(vi) on the surface of adsorbent because the curves showed that the adsorption led to saturation [11]. fig. 6. effect of contact time on adsorbed amount of cr(vi) on zac at different initial concentration (cr(vi) conc., 50–450 mg/l; volume of cr(vi) solution, 20 ml; amount of activated carbon, 0.02 g; ph, 2 ; contact time, 5.5 h) fig. 7. effect of contact time on adsorbed amount of cr(vi) on date seeds at different initial concentration (cr(vi) conc., 50–450 mg/l; volume of cr(vi) solution, 20 ml; amount of activated carbon, 0.02 g; ph, 3 ; contact time, 0.5-5.5 h) the three kinetic models: pseudo-first order pseudosecond order and intraparticle diffusion models, eqs. (7)– (8) ,where applied to the experimental kinetic data of cr(vi), which determined from eq. (2). table (4) and (5) for zac and date seeds as adsorbents, respectively, showed the values of r2 and calculated constants of the three kinetic equations at different initial cr concentrations. the linear plot of ln(qe – qt ) versus t (fig.6) and (fig. 7) for pseudo-first order equation , as shown in table (4) and table (5), the value of r2 was low and that representing a poor pseudo-first order fit to the experimental data. (fig. 8) and (fig. 9) with linear plot of t/qt versus t for pseudo-second order equation, high r2 values are obtained as shown in table( 4) and table( 5). it clear that the adsorption kinetics better represent by pseudo-second order kinetic model, and that mean that the adsorption of cr (vi) on zac and date seeds fitting with second-order kinetics. therefore, it may be concluded that cr(vi) adsorption onto produced carbon consist of chemical adsorption due to the fact that pseudo-second-order kinetic model suggests that adsorption process involves chemisorption mechanism .and that agreed with the result obtained by k. j. cronje et al. [12] for adsorption of cr(vi) using activated carbon prepared onto sugarcane bagasse activated with zinc chloride. table 4. kinetic parameters for cr adsorption on date seeds co(mg/l) first order model-pseudo qe, exp qe, cal k1 r2 (mg/g) (mg/g) (1/min) 50 150 250 350 450 35.203 94.532 132.954 154.355 170.033 3.998 5.659 7.1527 8.0156 7.744 0.4926 0.53007 0.7257 0.7634 0.7428 0.9544 0.9550 0.9946 0.9839 0.9790 second order model-pseudo(mg/l) oc qe, exp qe, cal k2 r2 (mg/g) (mg/g) (g/mg min) 50 150 250 350 450 35.203 94.532 132.95 154.35 170.03 37.335 98.483 147.51 177.18 189.35 1.3235 1.9004 1.5986 1.5139 1.6484 0.992 0.987 0.997 0.999 0.998 intraparticle diffusion model (mg/l) oc qe, exp c k3 r2 (mg/g) (mg/g) (mg/g min 1/2 50 150 250 350 450 35.203 94.532 132.95 154.35 170.03 9.0943 42.813 43.155 45.539 52.177 11.433 22.161 43.504 55.184 58.593 0.9527 0.979 0.953 0.926 0.881 table 5. kinetic parameters for cr adsorption on zac co(mg/l) model first order-pseudo qe, exp qe, cal k1 r 2 (mg/g) (mg/g) (1/min) 50 150 250 350 450 46.95 128.0 179.69 200.30 210.65 4.89 7.70 8.76 9.80 9.20 0.620082 0.734123 0.771996 0.83976 0.7747 0.925 0.9542 0.9948 0.9810 0.9983 second order model -pseudo(mg/l) oc qe, exp qe, cal k2 r 2 (mg/g) (mg/g) (g/mg min) 50 150 250 350 450 46.95 128.90 179.69 200.30 210.65 51.54 144.21 205.21 232.55 238.09 1.224 1.338 1.316 1.204 1.458 0.9804 0.9948 0.9979 0.9984 0.9998 intraparticle diffusion model(mg/l) oc qe, exp c k3 r 2 (mg/g) (mg/g) (mg/g min 1/2 ) 50 150 250 350 450 46.95 128.90 179.69 200.30 210.65 13.42 36.81 45.88 46.05 57.68 14.72 43.16 65.04 75.04 74.89 0.9902 0.9901 0.9619 0.9836 0.9417 samar k. theydan / iraqi journal of chemical and petroleum engineering91,9 (2018) 9-12 8 fig. 8. pseudo-first order kinetic for cr(vi) adssorption on zac at different concentrations (cr(vi) conc., 50– 450 mg/l; volume of cr(vi) solution, 20 ml; amount of activated carbon, 0.02 g; ph, 2 ; contact time, 0.5-5.5 h) fig. 9. pseudo-first order kinetic for cr(vi) adsorption on date seeds at different concentrations (cr(vi) conc., 50– 450 mg/l; volume of cr(vi) solution, 20 ml; amount of activated carbon, 0.02 g; ph, 3 ; contact time, 0.5-5.5 h) fig.10. pseudo-second order kinetic for cr(vi) adsorption on zac at different initial concentrations (cr(vi) conc., 50–450 mg/l; volume of cr(vi) solution, 20 ml; amount of activated carbon, 0.02 g; ph, 2 ; contact time, 0.5-5.5 h) fig. 11. pseudo-second order kinetic for cr(vi) adsorption on date seeds at different initial concentrations (cr(vi) conc., 50–450 mg/l; volume of cr(vi) solution, 20 ml; amount of activated carbon, 0.02 g; ph, 3 ; contact time, 0.5-5.5 h) 3.5. the intraparticle diffusion model the intraparticle diffusion mode was determined from eq.(9) . the linear plot of qt versus t 1/2 and from the slopes of the plots the values of k3 were determined. the c values gave a thought about the boundary layer thickness, when the intercept was larger, that made surface sorption was the rate controlling step. if the intraparticle diffusion is involved in the adsorption process, then the plot of qt versus t1/2 would result in a linear relationship, and the intraparticle diffusion would be the controlling step if this line passed through the origin [60] . fig.(12) and fig. (13) represent the data for the adsorption of cr(vi) on to zac and date seeds applied to intraparticle diffusion model and the results are given in table (4) for zac and table (5) for date seeds consistent with eq. (9). it can be seen from the shape of fig. (12) and fig.(13) shows strait lines not passed through the origin for most studied initial concentrations of cr(vi) which indicate that the intraparticle diffusion is not only the rate controlling step for the adsorption of the cr(vi) on zac and date seeds. the values of intercept c in table (4) and table (5) provide an information about the thickness of the boundary layer, i.e. the resistance to the external mass transfer. the larger the intercept is the higher the external resistance from these tables it can be seen that the c value increase with increase of initial cr(vi) concentration, which indicated increase of the thickness of the boundary layer and hence increase of the chance of internal mass transfer and decrease of the chance of the external mass transfer. samar k. theydan / iraqi journal of chemical and petroleum engineering91,9 (2018) 9-12 9 fig. 12. intraparticle diffusion plot for cr(vi) adsorption on zac at different initial concentration (cr(vi) conc., 50–450 mg/l; volume of cr(vi) solution, 20 ml; amount of activated carbon, 0.02 g; ph, 2 ; contact time, 0.5-5.5 h) fig. 13. intraparticle diffusion plot for cr(vi) adsorption on date seeds at different initial concentration (cr(vi) conc., 50–450 mg/l; volume of cr(vi) solution, 20 ml; amount of activated carbon, 0.02 g; ph, 3 ; contact time, 0.5-5.5 h) 4conclusions the main conclusions that can be drawn from this study are:  chemical activation of date seeds with zinc chloride with corresponding yield of 43 % , at impregnation ratio 1.25 g/g and carbonization temperature 500 ˚c for carbonization time 2 h , produced activated carbon with 1012.91 mg/g iodine number and 1050.01 m 2 /g surface area.  a cr(vi) adsorbed amount 35.6 mg/g were obtained at 2 solution ph, zac adsorbent weight 0.02 g , and 120 min contact time.  solution ph of 3, date seeds adsorbent weight 0.02 g , and 120 min contact time gave maximum 26.49 mg/g adsorbed amount.  maximum cr(vi) adsorption capacity of activated carbons prepared by zinc chloride and date seeds were 210.651 and 170.033 mg/g, respectively was obtained at operating conditions of 2 ph value for zac and 3 ph for date seeds as adsorbent , 0.02g/20ml adsorbent dose and 4.5 h contact time.  the maximum uptake of activated carbons prepared by zinc chloride and date seeds, as calculated from sips isotherm model, were 233.493 and 208.055 mg/g , with r 2 value of 0.9999 and 0.9998, respectively .  the adsorption kinetic data were well described by the pseudo -second order model for both zac and date seeds which provides the higher correlation coefficient and calculated qe agree well with the experimental data.  the intraparticle diffusion played a significant role, but it was not the main rate-determining step during adsorption of chromium on zac and date seeds. acknowledgment we gratefully acknowledge university of baghdad for assist and support of this work. nomenclature co : initial concentration of cr(vi) (mg/l). ce : equilibrium concentration of cr(vi) (mg/l). w : mass of activated carbon used (g). qm : maximum amount of cr(vi) adsorbed per unit mass of activated carbon (mg/g). r 2 : correlation coefficient . v : volume of aqueous cr(vi) solution (l). wf : weight of dried date seeds (g). wo : weight of final activated carbon (g). abbreviations zac : activated carbon by zinc chloride . cr(iv) : hexavalent chromium ion . gds : granular date seeds. references [1] s. heydari, h. sharififard, m. nabavinia, h. kiani, m. parvizi, (2013) , adsorption of chromium ions from aqueous solution by carbon adsorbent , international journal of environmental, ecological, geological and mining engineering , vol:7 no:12,632-635 . [2] hakan demiral , ilknur demiral, fatma t¨umsek, belgin karabacako˘glu ,(2008), adsorption of chromium(vi) from aqueous solution by activated carbon derived from olive bagasse and applicability of different adsorption models, chemical engineering journal ,144 , 188–196. [3] mina gholipour, hassan hashemipour and maryam mollashahi,(2011), hexavalent chromium removal from aqueous solution via adsorption on granular samar k. theydan / iraqi journal of chemical and petroleum engineering91,9 (2018) 9-12 01 activated carbon : adsorption ,desorption ,modeling and simulation studies , arpn journal of engineering and applied sciences,vol. 6, no. 9,1018. [4] k. mohanty, m. jha, b.c. meikap, m.n. biswas, removal of chromium (vi) from dilute aqueous solutions by activated carbon developed from terminalia arjuna nuts activated with zinc chloride, chem. eng. sci., 60, 3049–3059. [5] a. a. attia, s. a. khedr and s. a. elkholy,(2010), adsorption of chromium ion (vi) by acid activated carbon , brazilian journal of chemical engineering, vol. 27, no. 01, pp. 183 – 193. [6] jung, r. s. and shiau, r. c., (2000) ,metal removal from aqueous solution using chitosan enhanced membrane filtration. j. membrane science, 165(2), 159 . [7] donati, e., oliver, c. and curutchet, g., (2003),reduction of chromium (vi) by the indirect action of thiobacillus thioparus. braz. j. chem. eng. 20(1), 69 . [8] yang, g. y. and viraraghavan t.,(2001), heavy metal removal in biosorption column by immobilized mrouxii biomass. bioresource tech. 78(3), 243 . [9] luo c, tian z, yang b, zhang l, yan s., (2013),manganese dioxide/iron oxide/acid oxidized multi-walled carbon nanotube magnetic nanocomposite for enhanced hexavalent chromium removal. chem eng j , 234,256–265. [10] jyotikusum acharya , j.n. sahub, b.k. sahoo, c.r. mohanty, b.c. meikap ,(2009), removal of chromium(vi) from wastewater by activated carbon developed from tamarind wood activated with zinc chloride, chemical engineering journal ,150, 25–39. [11] z.a. al-othman, r. ali , mu. naushad, (2012), hexavalent chromium removal from aqueous medium by activated carbon prepared from peanut shell: adsorption kinetics, equilibrium and thermodynamic studies, chemical engineering journal, 184 , 238– 247. [12] k.j. cronje , k. chetty , m. carsky , j.n. sahu , b.c. meikap , (2011) , optimization of chromium(vi) sorption potential using developed activated carbon from sugarcane bagasse with chemical activation by zinc chloride, desalination ,275, 276–284. [13] f. di natale , a. lancia , a. molino , d. musmarrab, (2007), removal of chromium ions form aqueous solutions by adsorption on activated carbon and char, journal of hazardous materials ,145, 381– 390 . [14] i.a.w. tan, a.l. ahmad, b.h. hameed, (2008) ,adsorption of basic dye using activated carbon prepared from oil palm shell: batch and fixed bed studies, desalination ,225, 13–28. [15] m.j. ahmed, s.k. theydan, (2012), equilibrium isotherms and kinetics modeling ofmethylene blue adsorption on agricultural waste-based activated carbons, fluid phase equilibria, 317 , 9–14. [16] hatem a. al-aoh, rosiyah yahya, m. jamil maah, m. radzi bin abas, (2013), adsorption of methylene blue on activated carbon fiber prepared from coconut husk: isotherm, kinetics and thermodynamics studies, desalination and water treatment, 1–13. [17] adekola f.a. and adegoke h.i., (2005), adsorption of blue-dye on activated carbons produced from rice husk, coconut shell and coconut coir pitch, ife journal of science, 7(1), 151-157. [18] mohd adib yahya ,z. al-qodah , c.w. zanariah ngah ,(2015), agricultural bio-waste materials as potential sustainable precursors used for activated carbon production:a review, renewable and sustainable energy reviews,46, 218–235 [19] muthanna j. ahmed , samar k. theydan ,(2012), physical and chemical characteristics of activated carbon prepared by pyrolysis of chemically treated date stones and its ability to adsorb organics, powder technology ,229 , 237–245. [20] dinesh mohan , charles u. pittman jr. ,(2006), activated carbons and low cost adsorbents for remediation of triand hexavalent chromium from water, journal of hazardous materials ,b137 ,762– 811. [21] bouchelta c., medjran m.s., bertrand o., and bellat j., (2008), preparation and characterization of activated carbon from date stones by physical activation with steam, j. anal. appl. pyrolysis, 28, 7077. [22] girgis b. s., el-hendawy a. a.,(2002), porosity development in activated carbons obtained from date pits under chemical activation with phosphoric acid ,micropor mesopor mater ,52,2 ,105–17. [23] hayashi j., horikawa t., takeda i., muroyama k., ani f. n. ,(2002) ,preparing activated carbon from various nutshells by chemical activation with k2co3 ,carbon, 40, 13,2381–6. [24] hsu l., teng h.,(2000), influence of different chemical reagents on the preparation of activated carbons from bituminous coal, fuel process technol. ,64,(1–3),155–66. [25] puziy a. m. , poddubnaya o. i., martinez alonso a., suarez garcia f., tascon j. m. d.,(2005), surface chemistry of phosphorus-containing carbons of lignocellulosic origin, carbon ,43,14,2857–68. [26] suarez garcia f., martinez alonso a., tascon j. m. d. , (2002), pyrolysis of apple pulp: chemical activation with phosphoric acid, j anal .appl. pyrolysis,63,2, 283–301. [27] alhamed y.a., (2006), activated carbon from date stones by zncl2 actiivation, jkau: eng. sci., 17 (2), 75-100. [28] tan i.a. w., hameed b.h. and ahmad a.l., (2007), equilibrium and kinetic studies on basic dye adsorption by oil palm fiber activated carbon, chem. eng. j., 127, 111-119. [29] ahmedna m., marshall w.e., rao r.m., and clarke s.j., (1997), use of filteration and buffers in raw sugar colur measurement, j. sci. food agric., 75(1), 109116 samar k. theydan / iraqi journal of chemical and petroleum engineering91,9 (2018) 9-12 00 [30] adekola f. a., adegoke h. i., (2005),adsorption of blue-dye on activated carbons produced from rice husk, coconut shell and coconut coir pitch, ife, journal of science, 7 ,151–157. [31] astm standard, standard test method for total ash content of activated carbon,designation, d2866-94 (2000). [32] lubrizol standard test method, iodine value, test procedure aatm 1112-01, october 16 (2006). [33] brunauer s., emmett p.h., and teller e., (1938), adsorption of gases in multimolecular layers, j. am. chem. soc., 60, 309-319. [34] lowell s., shields j. e., thomas m. a., thommes m.,(2004), characterization of porous solids and powders: surface area, pore size and density, kluwer academic publishers, netherland. [35] demiral h., demiral i., f. tumsek f., karabacakoglu b.,(2008) ,adsorption of chromium(vi) from aqueous solution by activated carbon derived from olive bagasse and applicability of different adsorption models, chem. eng. j. ,144, 188– 196. [36] langmuir i., (1916), the constitution and fundamental properties of solids and liquids, j. am. chem. soc., 38, 2221-2295. [37] freundlich h.m.f., (1906), über die adsorption in lösungen, z. phys. chem., 57, 385-470. [38] sips r., (1948), combined form of langmuir and freundlich equations, j. chem. phys., 16, 490-495. [39] hall k. r. , l.c. eagleton l. c., acrivos a., vermeulen t.,(1966), poreand solid-diffusion kinetics in fixed-bed adsorption under constant-pattern conditions, industrial and engineering chemistry fundamentals, 5 , 212–223. [40] langergen s., svenska b. k., (1898),zur theorie der sogenannten adsoption geloester stoffe, veteruskapsakad handlingar ,24 ,1–39. [41] ho y. s., mckay g., (1999),pseudo-second order model for sorption processes, process biochemistry, 34 , 451–465. [42] weber w. j., morris j. c.,(1963), kinetics of adsorption on carbon from solution, journal of sanitary engineering division. american society of civil engineers, 89, 31–60. [43] k. suresh kumar ,ahmed al shoaibi .c.srinivasakannan ,(2012) , activated carbon from date palm seed : process optimization using response surface methodology, waste and biomass valorization , 3,2, 149-156. [44] haimour n.m. and emeish s., (2006), utilization of date stones for production of activated carbon using phosphoric acid, waste management, 26, 651-660. [45] v.k. singh, p.n. tiwari,(1997), removal and recovery of chromium(vi) from industrial waste water, j. chem. technol. biotechnol., 69, 376– 382. [46] m. rao, a.v. parwate, a.g. bhole, (2002),removal of cr6+ and ni2+ from aqueous solution using bagasse and fly ash, waste manag. ,22 , 821–830. [47] dilek durano˘glu , andrzej w. trochimczuk , ulker beker, (2012), kinetics and thermodynamics of hexavalent chromium adsorption onto activated carbon derived from acrylonitrile-divinylbenzene copolymer, chemical engineering journal, 187, 193– 202. [48] j. acharya, j.n. sahu, b.k. sahoo, c.r. mohanty, b.c. meikap, (2009),removal of chromium(vi) from wastewater by activated carbon developed from tamarind wood activated with zinc chloride, chem. eng. j. ,150, 25–39. [49] y.a. aydin, n.d. aksoy, (2009),adsorption of chromium on chitosan: optimization, kinetics and thermodynamics, chem. eng. j. ,151 , 188–194. [50] z. aksu, e. balibek,(2007), chromium(vi) biosorption by dried rhizopus arrhizus: effect of salt (nacl) concentration on equilibrium and kinetic parameters, j. hazard. mater. ,145 , 210–220. [51] n.k. hamadi, x.d. chen, m.m. farid, m.g.q. lub,(2001), adsorption kinetics for the removal of chromium(vi) from aqueous solution by adsorbents derived from used tyres and sawdust, chem. eng. j. ,84, 95–105. [52] b. royer, n.f. cardoso, e.c. lima, j.c.p. vaghetti, r.c. veses, (2009), applications of brazalin pinefruit shell in natural and carbonized forms as adsorbents to removal of methylene blue from aqueous solutions: kinetics and equilibrium study, journal of hazardous materials ,164 , 1213–1222. [53] a.m.m. vargas, a.l. cazetta,(2011), m.h. kunita, t.l. silva, v.c. almeida, adsorption of methylene blue on activated carbon from flamboyant pods (delonix regia): study of adsorption isotherms and kinetic models, chemical engineering journal ,168, 722–730. [54] e. oguz,(2005), adsorption characteristics and the kinetics of the cr(vi) on the thuja oriantalis, colloid surf., 252 , 121–128. [55] n. daneshvar, d. salari, s. aber,(2002), chromium adsorption and cr(vi) reduction to trivalent chromium in aqueous solutions by soya cake, j. hazard. mater., 94, 49–61. [56] p.k. malik, (2004),dye removal fromwastewater using activated carbon developed from sawdust: adsorption equilibrium and kinetics, j. hazard. mater.,113 , 81–88. [57] lotfi khezami, richard capart,(2005), removal of chromium(vi) from aqueous solution by activated carbons: kinetic and equilibrium studies, journal of hazardous materials ,b123, 223–231 [58] k. selvi, s. pattabhi, k. kadirvelu,(2001), removal of cr(vi) from aqueous solution by adsorption onto activated carbon, bioresour. technol., 80, 87–89. [59] ahmed el nemr, azza khaled, ola abdelwahab, amany el-sikaily,(2008), treatment of wastewater containing toxic chromium using new activated carbon developed from date palm seed , journal of hazardous materials ,152 , 263–275. samar k. theydan / iraqi journal of chemical and petroleum engineering91,9 (2018) 9-12 02 [60] g. crini, h.n. peindy, f. gimbert, c. robert,(2007), removal of c.i. basic green 4 (malachite green) from aqueous solutions by adsorption using cyclodextrin-based adsorbent: kinetic and equilibrium studies, sep. purif. technol. ,53 ,97–110. الخالصة ي وباستعمال كلوريد الزنك يهدف البحث إلى ازالة ايون الكروميوم باستخدام نوى التمر المطحون و الكاربون المنشط المحضر من نوى التمر بطريقه التنشيط الكيميائ متر 1050501نتائج الكاربون المنشط الناتج باستخدام كلوريد الزنك كعامل منشط كان ذو مسحه سطحيه )كعامل منشط. ايضا بينت ال 2 /غرام( ونسبه امتزاز لليود ) متر 500503تم تحديد المساحة السطحية و نسبة امتزاز اليود ملغرام / غرام(. بينما 1012591 2 ph (2-12 )قيمة غرام . تم دراسة تأثير / ملغرام 485578/غرام و تم الحصول سعه امتزاز دقيقة( . 150-30غرام ( و زمن امتزاز )05036-05004( ملغرام/ لتر 5 وكمية المادة المازة )450550 التركيز االولي ل ايون الكروميوم ) زمن غرام( 5 و0502وزن المادة المازه الى) ph(2 5) غيليه : ملغم/غرام( عند الظروف التش 3556أليون الكروميوم عند استخدام الكاربون المنشط بالزنك كلورايد ) وزن ماده ph (3 5)ملغم/غرام( عند الظروف التشغيليه : 26549تم الحصول على سعه امتزاز ) دقيقه(. في حين عند استخدام نوى التمر كمادة مازة 5 120) امتزاز تم استخدام معادله سيبس بشكل ناجح لتمثيل نتائج امتزاز ايون الكروميوم على الكاربون المحضر ونوى التمر 5 حيث .دقيقه(120 ) زمن امتزاز غرتم( 5 و 0502مازه ) ملغم/غرام( على التوالي.ايضا تم دراسة حركية 2085055ملغم/غرام( و )2335493)اعطى اعلى سعه امتزاز اليون الكروميوم على الكاربون المحضر ونوى التمر لمحضر ونوى التمر . متزاز و بينت النتائج ان معادلة الدرجة الثانية مثلت النتائج التجريبية لعملية االمتزاز بشكل جيد ل ايون الكروميوم على الكربون اعملية اال iicpi*,' -'"]3i:lit':i,il i,'i::r;*.** kincric rnd isotncrm i\'lodclnr:l ol adsor lrion of dycs onl! sn*dust k a 6 d d d n * i g . ; n k € d i o r . n r l " ^ d " * , , . 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"d.ri" dk "" nde for db sd v' ' . g * * | j ' f t . 1 * ' . o u i . d d k h & f o t r i d b h . o ' a ] ' b h g m m d d 0.12t4 dnsnii 6r db dd w 6p.dedv { te trt4-i f' di'--, ,orq ijcpe vor 11 no 2(june 20r o) ,,-"1 .,sfr lil.r.0r!3),,mc adsq'bn ors onpuocr m c ( . y , c r " d m c ^ r 4 q , g , ( r e t 3 ) " o a r i r&\mhg\. (ree9, !s r l v . k r c n i a i d w . i ' r b y l n ( e t s ) f i , d e d (reto). rr! irrlr d (2006r rl[d i r.oe.r*ioi. r2 (4). xj.tj7 6 l i , s r r ( ! r ) . c. od acry r.r 11e78). aid h{ry ir (rt76). d! dsoll,eic].9|wndrs@|\|0'10611066 0err). conp'a. r ad muiidriyn 0ee6), "r€ffodori'6i'on4u@6sd]lljoibre|[h5t kfthne v.rv. 0eeo. r: naeli s.s od tun! 3. 0e3e), tunowl ofdlr ri a lr.tr,s r . k@uned43.(?005)," ba. dtc (mdhy*e bjuo @morl fron sindnd !*rsa&r r4 satrr s ̂ ,gheiy a.1., suh&dy d.. (200t. 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( i q 0 ) ^ d r r i s i d , o r: !urhi.! m. rdehrr ji.r !(ie17).'eqn'6r o?rdi,i.s(1001)"b sof i, n yo!x.^rdwi.b.(:00t"kiid c 'no& h ot ,r-kdnh4d,n.n6iy3yam.c i?0o7fd&.mflbl ard l i i d i c n u d i € 9 o n n d h y t r c 6 ! d d $ e i o t b y @ r ,6 ho,y.s ,mckay,g ( |eee), contsnrive $eron m.h3hrsrfi. k q009."adso ior rhdts of $,itj appied scieiv.b6ridi3.r,z6] :3 rob eon,a. chddi,b, ntan,p ,c002),"rmor m'hjolbb ' sctrlrm.,(2007),"adso@ii. po,idoi d4iicll) ibq biongr"hl r.eiviroi.sci rd.,4,(4)3r3!10. ro bbrr4m,mcmurr.i.c.,mchd.,a.poe9d, dzhdkiesiqs.,cooo, a mnpd$i or elprlon ciitogl"'prcg*oichdist'ad'pp|iqliioi u c p e v o ! s n o 4 l l l n e 2 0 1 0 ) htu,.d ),.n-^ m"re !:! :9r9v t!!!94gi!:! rt*fl*.lntfd:gl'rys "l#:''m+*ir';tt i ;l ucpe vol 11 no 2(june 2010) iraqi journal of chemical and petroleum engineering vol.16 no.2 (june 2015) 3137 issn: 1997-4884 improving treatment performance of dissolved air flotation system by using ionic liquids as surfactants sawsan a.m. mohammed and aws abbas fadhil chemical engineering department – college of engineering – university of baghdad abstract the effect of three ionic liquids viz., 1-hexyl-3-methylimidazolium tetrafluoroborate (ile), 1-hexyl-3-metylimidazolium hexafluorophosphate (ilf) and 1-octyl-3-methylimidazolium tetrafluoroborate (ilg) when used as surfactants on the performance of dissolved air floatation (daf) was investigated. experiments were conducted at a temperature of 30-35 ºc, 10ppm ferric chloride as coagulant, 50% recycle ratio, ph 8, and 10 minutes treatment time to find oil and grease (og) and turbidity removal efficiencies at saturation pressure (2-6) bar. ils were used at concentration of 50 µl/liter of treated water in two positions in daf system; the saturation vessel and the treatment tank. the performance using ils in the saturation vessel were better than that in treatment tank because ils reduced the surface tension of water, which lead to an increase in the solubility of air in water and eventually increase the microbubble formation. the og removal efficiency using ilg as an efficient surfactant in saturation vessel was higher than that in the treatment tank and higher than other ils (ilg>ilf>ile). the removal efficiency reached about 90% at a saturation pressure of 5 bar, and 85% at 3 bar, which reduces the operation costs. the treated water oil concentration at 3bar was 9.5 ppm, which meets the iraqi pre-disposal regulatory limit. key words: produced water, daf system, ionic liquids introduction dissolved air flotation technique had gained widespread usage over the last forty years for the removal of suspended solids (tss), oils and greases (og), and biochemical oxygen demand (bod) from wastewater and other industrial process streams. produced water is water trapped in underground reservoir rocks, which can be brought to surface along with crude oil and gas. water produced during oil and gas extraction operations constitutes the industry’s most important waste stream. the large amount of water represents a potential problem to the environment and to the oil production industry that needed to be solved. in this situation, produced water can be classified into formation water, injection water and process water, which is extracted along with oil and gas during petroleum production [1]. basically, produced water contains dissolved and insoluble petroleum fractions, which are similar to that found in crude oil and natural gas [2]. the insoluble petroleum fractions tend to disperse in the form of small iraqi journal of chemical and petroleum engineering university of baghdad college of engineering improving treatment performance of dissolved air flotation system by using ionic liquids as surfactants 32 ijcpe vol.16 no.2 (june 2015) -available online at: www.iasj.net droplets in the water. this represents an oily water and most of it is existed in the form of oil-in-water (o/w) emulsions [3]. a good knowledge of petroleum emulsions is significant for monitoring and improving processes at all steps. many studies have led to better consideration of these complex systems [4]. emulsion behavior is largely controlled by the properties of the adsorbed layers that stabilized the oil– water surfaces. in addition other factors can be very effective on this stability like viscosity, produced water type, agitation etc. [5]. many separation methods were used during the past decades like mechanical, heating, electrical and chemical demulsification. every technique has advantages and faults. these methods include: de-oiling (removal of dispersed oil and grease), desalination, removal of suspended particles and sand, removal of soluble organics, removal of dissolved gases, removal of naturally occurring radioactive materials (norm), disinfection and softening (to remove excess water hardness). until now there is no technique that could reach complete destabilization without grouping with another one [6]. for many applications of flotation in the wastewater treatment field, it is more efficient to use micro-bubbles generated by nucleation of dissolved air, rather than the dispersed air method used for minerals. flotation offers process advantages over sedimentation, including better treatedwater quality, rapid startup, high rate operation, and thicker sludge. dissolved air flotation (daf) is considered not only an alternative to sedimentation plants, but also a clarification method to improve filtration [7]. dissolved air flotation uses pressure saturation to increase the solubility of air in water to produce fine microbubbles for oil removal. the idea is to develop agglomerates with lower density than water, causing the oil droplets to rise through the water and accumulate at the surface where they can be removed [8]. dissolved air flotation is an effective method of oil from water separation because the high concentration of microbubbles and their slow rise rates allow for more collision opportunities with the oil droplets [9]. treatment of produced water is controlled by disposal regulatory limits or beneficial reuse specifications (e.g. agricultural usage, potable purpose and industrial field, etc.); these limits include oil and grease, toxicity, and other constituents [10]. ionic liquids (ils) are considered one of the promising alternative materials for different applications. they are defined as salts with melting temperatures below 100°c, evolved from traditional high temperature molten salts, consisting of organic cations combined with anions of organic or inorganic nature. the chemical structure of ils allows many combinations of anions and cations, enabling one to obtain compounds with properties quite varied, which means that tailor-made ils can be produced for a given application [11,12]. for nearly two decades, ils attracted the quickly growing attention due to their outstanding properties: wide liquid range, low volatility, high thermal stability, low toxicity, high ionic conductivity, wide electrochemical window, etc. this makes many ils perspectives for applications in various fields of chemistry and technology and determines their importance for “green” chemistry [13]. ils are expected as superior environmentally friendly solvent for chemical synthesis, sawsan a.m. mohammed and aws abbas fadhil -available online at: www.iasj.net ijcpe vol.16 no.2 (june 2015) 33 homogeneous catalysis, biocatalysts, separation technologies, nanomaterial preparations, templates for production of porous solids, hydraulic fluids, and lubricants [14]. the aim of this research is to examine a technology to improve the performance of a dissolved air flotation (daf) system in treating oilfield produced water through pretreatment with coagulants and the use of ionic liquids as surfactants. experimental work materials raw produced water obtained from middle oil company (md.o.c) (east of baghdad fields) with initial oil and grease concentration of (60-80) ppm was used in daf experiments. chemicals used in daf experiments were hydrochloric acid, sodium sulfate anhydrous, carbon tetrachloride, ferric chloride anhydrous, sodium hydroxide, sodium chloride. ionic liquids used were 99% purity supplied by shanghi cheng jie chemical co, china. the physical properties of the ionic liquids are listed as given in table (1). table (1), physical properties of ionic liquids il nam e molecula r weight densit y g/ml meltin g point ˚c ile 254.08 1.15 181.85 ilf 312.24 1.25 -60.85 ilg 282.13 1.08 -79.85 batch dissolved air flotation unit in the current study, a batch daf unit located in the iraqi ministry of sciences and technology was used, as shown in fig. (1). fig. 1, batch daf unit schematic diagram ten liters of raw oil field produced water were poured into coagulation vessel. the ph value was controlled to 8 using naoh (0.5m) and hcl (0.1m). 10ppm of ferric chloride was added to the solution and subjected to rapid mixing (60-100 rpm). the final solution was then poured in flocculation tank after two minutes of mixing. the solution was subjected to low mixing speed (15 rpm) for thirty minutes resulting in an emulsion containing flocks. in case of using any of ils in treatment tank, they must be added to the raw produced water before using the coagulants. the final emulsion was poured in the treatment vessel. the needle valve between saturation tank and treatment vessel and also effluent valve must be kept close at this step. ten liters of demulsified produced water (trace oil concentration about 5ppm or less (50% recycle ratio) were added in the saturation tank through the entrance valve. compressor valve must be kept close at this step. in case of using ils in saturation tank, it must be added to demulsified produced water with mixing at (400500 rpm) before decanting in the saturation tank. the compressor was switched on and the entrance, vent and needle valves were closed. then the compressor improving treatment performance of dissolved air flotation system by using ionic liquids as surfactants 34 ijcpe vol.16 no.2 (june 2015) -available online at: www.iasj.net valve was opened and the pressure gauge controlled to typical values of (2, 3, 4, 5 and 6) bar for control case (which represents daf unit operation without using ils) and ils case (adding any of the three ils in daf unit) by controlling the vent valve (the pressure must be constant during running the daf experiment). the needle valve was used to control the rate of micro bubbles saturated water that transfer (by acting the of the pressure) from the saturation tank to the treatment tank. the needle valve was opened, allowing the water saturated with air micro bubbles to flow to the treatment tank, raising the oil layer over the surface of treated water. when the first large bubble appeared in the treatment tank, the needle valve was closed (ending daf operation) and operating time was recorded. the minimum operating time was not less than ten minutes and was controlled by the needle valve. the daf operating temperature range was (30-35) ˚c. the sample was decanted from effluent valve and subjected to analysis. total oil and grease concentration was measured by oil content analyzer (ocma – 350, horiba ltd, japan), the water turbidity was measured using turbidity meter (tb300ir, lovibond, germany), and the surface tension was measured by sigma 703a tensiometer (ksv instrument ltd, finland). results and discussion ils effect on the removal efficiency in this study three-imidazolium type ils were tested as new demulsifiers for iraqi oil field produced water. they were used as surfactant in the treatment of produced water in the batch daf unit. they were tested in the treatment tank and the saturation vessel as illustrated in the experimental procedure. the removal efficiencies were varied from one type to another according to the chemical composition, physical properties, and the usage position (treatment tank, or saturation tank). fig. (2) shows that ilg is the most effective il among the others, where removal efficiency reaches about 86% at saturation vessel pressure of 3 bar, while ile at the same conditions had the lowest performance with a removal efficiency not exceeding 76%. the increase in the og removal efficiency with respect to the control when using ilg in this case will be about 13% at a pressure of 3 bar. fig. 2, oil and grease removal efficiency using ils in the saturation vessel fig. 3 oil and grease removal efficiency using ils in treatment tank from fig. (3), it can be concluded that ilf was the most effective among other ils, where separation removal efficiency in treatment tank reached sawsan a.m. mohammed and aws abbas fadhil -available online at: www.iasj.net ijcpe vol.16 no.2 (june 2015) 35 about 82% at saturation vessel pressure of 3 bar, while it was (72% and 66%) for ilg and ile respectively. final og concentration due to used efficient ils in saturation vessel and treatment tank the final og concentrations due to the use of efficient ils in saturation vessel and treatment tank are shown in fig. (4) and fig. (5). fig. 4, final oil concentration when using ils in saturation vessel fig. 5, final oil concentration when using ils in treatment tank the bold curves in fig. (4) and fig. (5), represent the two efficient ils, ilg (1-octyl-3-methylimidazolium tetra fluoroborate) and ilf (1-hexyl-3metylimidazolium hexafluorophosphate) in the saturation vessel and treatment tank respectively. this study was focused on operating the batch daf unit to reduce pressure below 5 bar in order to decrease the operating costs. clearly, it was indicated that the treated water og concentrations due to using the efficient ilg in the saturation vessel and efficient ilf in the treatment tank were 9.5ppm and 12ppm as shown in fig. (4) and fig. (5), respectively when operating saturation pressure was 3bar. the treated water og concentration value (9.5ppm) at operation pressure 3bar (when using ilg as surfactant in the saturation vessel) was in agreement with iraqi rule no. 25 in 1967 [15] which stated that the oil and grease in wastewater effluent should not exceed 10 ppm. therefore1-octyl-3methylimidazolium tetrafluoroborate (ilg) was the most efficient surfactant among the other ils (ile and ilf) when used in saturation vessel. effect of using ils on bubble growth and nucleation the results of testing surface tension of treated md.o.c produced water in saturation vessel were used to calculate the energy required to form bubbles. takahashi relation [16] was used for this purpose:   3 0 3 16 4  a ppf  … (1) where δf: minimum energy to be transferred to the liquid phase to form bubbles by a cavity phenomenon (arising from the liquid turbulence), j γ: air/water surface tension (nm -1 ) pₒ and pa: the saturation and atmospheric pressure (pa), respectively. fig. (6) shows that increasing air pressure in the saturation vessel leads to raising air solubility in liquid phase and providing the energy for bubbles nucleation and surface formation. improving treatment performance of dissolved air flotation system by using ionic liquids as surfactants 36 ijcpe vol.16 no.2 (june 2015) -available online at: www.iasj.net fig. 6, effect of pressure upon bubbling energy when using ils in saturation vessel in the case of using low oily content produced water in the saturation vessel (control case) large bubbles are formed but the addition of a trace amount of any of ils (ile or ilf or ilg) provides low energy nucleation sites such that very minute bubbles, with a cloud-like appearance are generated. using any of the two ils (ile and ilg) required less nucleation energy (δf) than that of the ilf and the control during the applied pressure range (2-3) bar as illustrated in fig. (6). these results are in agreement with those of féris et al. [7], who showed that the energy transferred to form micro-bubbles will be smaller when the air/liquid interfacial tension is lower and the pressure difference of the liquid phase with respect to the atmospheric pressure is higher. thus, by lowering the air/liquid interfacial tension, the fluid velocity will be higher and the kinetic of bubble formation will be faster. these results are also in agreement with the results of dupre et al. [17], who reported that daf users observe a reduction in the diameters of the bubbles in the tanks when using "polyelectrolytes" and consider this and the use of surfactants a complex matter. conclusions 1the imidazolium group, ionic liquids showed good performance in demulsification process in batch daf unit. the og demulsification rate due to use the ils in the saturation vessel was higher than that when using the ils in treatment tank, this means that the pressure has a good impact upon the physicochemical properties of the ils and eventually increases the og removal efficiency. 2in the present study, the ilg (1octyl-3-methylimidazolium tetra fluoroborate) is used in the saturation vessel for the first time and is an efficient demulsifier for oil field produced water emulsion. the og removal efficiency approximately increased by 13% above that in the normal case (when using fecl3 with dose of 10ppm, ph8) at optimum pressure (5 bar). at 3 bar the og removal efficiency reached 85% and final effluent concentration of og was 9.5 ppm. this value was in agreement with the iraqi produced water discharge regulations, which indicates that og concentration in wastewater effluent to rivers should not exceed 10 ppm. 3using ils (ile, ilf and ilg) in saturation vessel as surfactant allowed micro bubbles generation at operating pressure lower than 3 bar with high-energy savings. references 1veil, j.a. and clark, c.e., (2009), “produced water volumes and management practices”, u.s. department of energy technology laboratory, pp. 7. 2tellez, g.t., nirmalakhandan, n. and gardea-torresdey, j. l., (2005), “comparison of purge and trap gc/ms and spectrophotometry for monitoring petroleum hydrocarbon degradation in oilfield produced sawsan a.m. mohammed and aws abbas fadhil -available online at: www.iasj.net ijcpe vol.16 no.2 (june 2015) 37 waters”, microchemical journal, vol. 81, pp. 12-18. 3fanchi, r. and john. (2006), "petroleum engineering handbook: general engineering", usa: society of petroleum engineers, richardson, vol. 1. 4langevin, d., poteau, s., henaut, i. and argillier, j., (2004), "crude oil emulsion properties and their application to heavy oil transportation", oil & gas science and technology, rev. ifp, vol. 59, no. 5, pp. 511-521. 5abdel-raouf and el-sayed manar, (2012),"crude oil emulsions composition stability", croatia: intech, rijeka, pp. 185. 6ebenezer, t. i. and george, z. c., (2014), "produced water treatment technologies", international journal of low-carbon technologies, sep., pp. 160. 7féris, l., gallina, s., rodrigues, r. and rubio, j.,(2000), "optimizing dissolved air flotation design system", braz. j. chem. eng., vol. 17, pp. 4-7. 8lundh, m., (2000), "experimental studies of the fluid dynamics in the separation zone in dissolved air flotation", wat. res. 34(1), pp. 21-30. 9al-shamrani, a., james, a. and xiao, h., (2002), "separation of oil from water by dissolved air flotation". colloids and surfaces a: physicochem. eng. aspects 209, pp. 15–26. 10veil, j. a., puder, m. g., elcock, d. and redweik, r. j. j., (2004), “a white paper describing produced water from production of crude oil, natural gas, and coal bed methane”, usa: u.s department of energy national energy. 11huddleston, j. g., visser, a. e., reichert, w. m., willuer, h. d., broker, g. a. and rogers, r. d., (2001), "characterization and comparison of hydrophilic and hydrophobic room temperature ionic liquids incorporating the imidazolium cution", green chem., vol.3, no. 4., pp. 156-164. 12kadokawa, j. i., (2013), "ionic liquids new aspects for the future", rijeka, croatia : in-tech,. 13smirnova, n. a. and safonova, e. a., (2010), " ionic liquids as surfactants", petersburg, russia : russian journal of physicalchemistry, vol. 84, no. 10, pp. 1695–1704. ijcpe vol.11 no.1 (march 2010) p iraqi journal of chemical and petroleum engineering vol.11 no.1 (march 2010) 59-63 issn: 1997-4884 the effect of operating conditions of urea dewaxing on the pour point of light lubricating oil. abdul-halim a.mohammed* and noor s.akram * chemical engineering department college of engineering university of baghdad – iraq abstract an investigation was conducted for dewaxing of lubricating oil fraction by urea to reduce the pour point.in this study mixture of 45 % methyl ethyl ketone (mek) and 55 % toluene was used as a solvent. the studied variables are mixing time (10-70 min), solvent to oil volume ratio (0.5:12:1), urea to wax weight ratio (26) and constant mixing speed 1500 rpm. by analysis of the experimental results, the best operating conditions achieved are mixing time 40 min, solvent/oil 2:1 volume ratio, and urea/wax 4:1 weight ratio. at these conditions the pour point of the lubricating oil decreases from 24 ° c to -13 °c. keywords: urea dewaxing, adduct, solvents, pour point. introduction wax is probably the most troublesome product in the manufacture of lubricating oil. its presence in lubricating oils prevents free movement at lower temperatures [1]. so all lube stocks must be dewaxed, except those from a relatively few highly naphthenic crude oils or those which do not flow properly at ambient temperatures [2]. many methods were used to remove the wax from lubricating oil distillate. the first process is solvent dewaxing process; solvent dewaxing can be applied to light, intermediate, and heavy lubricating oil distillates [3]. the main process steps include mixing the feedstock with the solvent, chilling the mixture to crystallize wax, and recovering the solvent [4]. the second process is catalyst process. catalytic dewaxing is a hydrocracking process and is therefore operated at elevated temperatures (280 to 400 °c) and pressures (300 to 1500 psi) [3], it removed n-paraffins and waxy side chains from other molecules by catalytically cracking them into smaller molecules [5]. the third process is called urea dewaxing. urea dewaxing is a process for producing low pour point oils, and using urea which forms a solid complex (adduct) with the straight chain wax paraffins in the stock. in contrast to the other dewaxing techniques, urea dewaxing can be achieved without the use of refrigeration, the process may be particularly useful for production of refrigerator oils, transformer oils, and the like [3]. in addition, the purity of recovered n-paraffin is often very low because of non-normal hydrocarbons participating in the adduct formation [6]. because of the oil viscosity, good contact between oil and urea is not achieved and difficulties are encountered during filtration, it is necessary to use a solvent to avoid these troubles. this solvent must dissolve oil and wax but not the urea [7]. it is also known that the selectivity of the urea dewaxing process may be improved by diluting the mineral oil distillate with oil solvents. suitable oil solvents include low molecular weight alcohols and ketones, low boiling hydrocarbon such as butane, pentane, isopentane, hexane, and the like, and halogenated hydrocarbons such as dicloromethane can be used [8]. urea selectively crystallizes around paraffinic hydrocarbons with long straight chains to make a solid, filterable complex or adduct. this selectivity of adduct formation is a function of the cross section of the hydrocarbon molecules as related to the geometry of the university of baghdad college of engineering iraqi journal of chemical and petroleum engineering the effect of operating conditions of urea dewaxing on the pour point of light lubricating oil. 60 ijcpe vol.11 no.1 (march 2010) urea crystal, figure 1 shows these relationships for different hydrocarbon molecules [9]. figure 1 relative sizes of urea adduct and specific hydrocarbons (9) the condition in the reactor (temperature, water content, urea to feed and solvent to feed ratio, flow and mixing, type of solvent and/or activator, etc.) will determine the structure of the adduct [10]. x-ray studies indicate that the crystal structure of urea changes from a tetragonal to a hexagonal system during the complex formation process. the urea molecules wrap around the straight chain molecules in a hexagonal spiral; the spirals form channels having a diameter of approximately 5 ˚a, large enough to accommodate straight chain molecules but not branched chain or cyclic molecules [6]. several previous studies have investigated the reduction of pour point by urea dewaxing. yata[11] used residual oil as feed to remove wax by using urea with the methanol-benzene solvent mixture. it was indicated that the pour point of each distillate fraction does not differ much with the solvent-dewaxed oil, but increases as the fraction becomes heavier with the urea-dewaxed oil. mead and wright[12] improved urea dewaxing process for naphthenic distillate using urea/alcohol slurry chilled to 60 to 65 °f for production of refrigerator oil with improved low temperature properties. yasin[13] made an investigation for the process of urea pour point reduction of heavy lubricating oil fraction methyl iso-butyl ketone and methylene chloride solvent were used. it was found that the pour point of the feed stock was lowered from 34 °c to about 4 °c when methyl iso-butyl ketone solvent was used while the pour point of the fraction lower to 7 °f when methylene chloride was used. this work deals with the study of the effect of operating condition on the urea dewaxing process of light lubricating oil fraction. experimental work materials a raffinate of furfural extraction of light lubricating oil fraction produced by vacuum distillation in al-duara refinery was used in this investigation as feed stock. table 1 shows the properties of the lubricating oil fraction. table 1 properties of light lubricating oil fraction. no. specification value 1 specific gravity @ 60/60 o f 0.860 2 viscosity, cst, @ 40 o c 24 3 viscosity, cst, @ 100 o c 4.6 4 viscosity index 115 5 pour point, o c 24 6 color 1.0 mixture of 45% of mek and 55% of toluene was used as a solvent. the mek causes the wax in the oil to crystallize, and the toluene is used to dissolve the oil. both the wax solution and the oil solution are distilled for removal of solvent (to be reused) and to provide solvent free wax and oil. thus the two products are wax-free oil and an oil-free wax . urea (carbamide or carbonyl diamide) is a colorless crystalline compound, formula ch₄n₂o with a nitrogen content of 46%. urea is a highly soluble in water. it is supplied from general company for production of chemical fertilizers. adduct formation during each experiment the reaction flask was heated and controlled by using a water bath with heater and thermostat as shown in figure 1. the flask also surrounded directly by a cooling coil which was used for cooling the flask contents. the oil fraction was mixed with the solvent and urea solution in the reaction flask at controlled specified temperature. chilled water is pumped from the chiller into the cooling coil in order to reduce the temperature of the flask mixture from initial reaction temperature 52 ̊c to the final reaction temperature 30 ̊c at the desired time and mixer speed. at the end of each experiment the resulted complex was used for adduct separation unit. adduct separation the separation of the adduct from the dewaxed oil take place by vacuum filtration. the separation of oil-solvent phase and urea saturated phase was completed by separating funnel to separate the adduct crystals. then abdul-halim a.mohammed and noor s.akram ijcpe vol.11 no.1 (march 2010) 61 these crystals is washed twice by using cold solvent (mek + toluene) and then re-filtered. adduct decomposition the adduct decomposition takes place at about temperature 80 ̊c to separate the wax from the urea dissolved in water. solvent recovery the solvent was recovered from the oil-solvent mixture by simple distillation pour point determination the pour point is the lowest temperature at which oil will move, pour, or flow when it is chilled without disturbance under definite conditions [3]. astm d97 was used to determine the pour point. the oil sample charged in a special tube and cooled, by using a succession of baths at ever lower temperatures [14], the pour point of a sample is determined to be 3 ̊c above the point at which a sample can be horizontally held and no movement occurs for five seconds[4]. results and discussion effect of mixing time figure 2 shows that the pour point against mixing time at different solvent/oil ratio, while figure 3 shows the pour point against mixing time at different urea/wax ratio. figure 2 indicate clearly that the pour point of dewaxed oil decreases with increase in solvent/oil ratio. the same trend of pour point is observed as urea/wax ratio increases, as shown in figure 3. the small increments in the pour point after 40 min may be due to the consumption of all the solvent through reaction and its no more reaction can occur between the feed stocks and the urea. fig. 2 effect of the mixing time on the pour point at different solvent/oil ratio. fig. 3 effect of the mixing time on the pour point at different of urea/wax ratio. the effect of operating conditions of urea dewaxing on the pour point of light lubricating oil. 62 ijcpe vol.11 no.1 (march 2010) effect of solvent/ oil (vol. /vol.) figure 4 shows that the pour point against solvent/oil at different of mixing time, while figure 5 shows that the pour point against solvent/oil at different of urea/wax. it can be seen from figure 4 that the pour point of the dewaxed oil decreases as solvent/oil increase at different mixing time. the same trend of the pour point of the dewaxed oil decreasing is observed as urea/wax increasing as shown in figure 5. this decreasing in the pour point may be to the change in the equilibrium between straight-chain hydrocarbon and urea that influenced by increasing of the ketone solvent, as also stated by bailey and co-workers [15], that found the solvent to feed ratio was to be important and it was necessary to maintain a sufficient solvent rate to the filter to effect adequate washing of the filter cake. fig. 4 effect of solvent/oil (vol. /vol.) on the pour point at different mixing time. fig. 5 effect of solvent/oil ratio on the pour point at different urea/wax ratio. effect of weight ratio of urea/wax. plot the pour point of the dewaxed oil against urea/wax at different mixing time is shown in figure 6, while figure 7 shows that the pour point of the dewaxed oil against urea/wax at different solvent/oil. fig. 6 effect of urea/wax on the pour point at different mixing time. fig. 7 the effect of the weight ratio of urea/wax on the pour point at different solvent/oil. figure 6 indicate that the pour point of the dewaxed oil was reduced with urea/wax increase up to 4 at different mixing time and solvent/oil volume ratio 2, and slightly increase in pour point occurs above 4 ratios. the same trend of the pour point of the dewaxed oil decrease is observed as urea/wax increases as shown in figure 7. according to the data taken from literatures [7,16,17], the stoichiometric amount of urea required to form an adduct with n-paraffin is about 3.5 gram of urea for each gram of n-paraffin. due to that using quantity of urea lower than the stoichiometric amount (deficient urea) leads to extract less n-paraffin and produces less adduct crystals. treatments with large amount of aqueous urea were avoided here because in this case mixtures of hydrocarbons and an aqueous phase are difficult to separate. abdul-halim a.mohammed and noor s.akram ijcpe vol.11 no.1 (march 2010) 63 conclusions the possibility of studying urea dewaxing of lubricating oil in four stages adduct formation, adduct filtration, adduct decomposition and solvent recovery. the recommended best conditions for pour point of the dewaxed oil were 40 min mixing time, 2 volume ratio of solvent/oil, and 4 weight ratio of urea/wax. at these conditions the pour point of the dewaxed oil decreased from 24 to -13 ˚c. references 1. board n., "modern technology of petroleum, greases, lubricants, and petrochemicals", niir project consultancy services (npcs), india, 2004. 2. gary j.h., "petroleum refining technology and economics", 4 th ed., marcel dekker inc., new york, 2001. 3. speight j.g., "the chemistry and technology of petroleum", 4th ed., crc press, taylor and francis group, llc, 2007. 4. hsu c.s. and robinson p.r., "practical advances in petroleum processing", 1, springer science and business media, inc., 2006. 5. kramer d.c., lok b.k., and krug r.r., amer. soc. for testing and materials, west conshohocken, pa, 2001. 6. hassan, n.m., butterworth-heinemann, vol. 4, 6264, 1994. 7. marechal j. and radzitzky p., j. inst. pet., 46 (434), 33 – 45 (1960). 8. kunert, maximilian, sandhack and lothar, u. s. patent, 3847791, 1974. 9. rogers t.h., brown j.s., diekman r. and kerns g.d.,oil and gas j., pet. ref., 36 (5), 217 – 220, july (1957). 10. mcketta j.j. and cunningham w.a, "encyclopedia of chemical processing and design", crc press, 15, 1976. 11. yata n., bulletin of the japan pet. inst., 4, 35-44, 1962. 12. mead t.c., and wright j.h., u.s. patent, no. 4504376, 1984. 13. yasin s.r., "dewaxing of distillate oil fraction (400500 °c) using urea", ph. d. thesis, submitted to the college of engineering, university of baghdad, 2005 14. denis j., briant j. and hipeaux j.c., "lubricant properties, analysis and testing", translated from the french by dr. g. dobson, published by editions technip, paris, 2000. 15. bailey m.a., bannerot r.a., fetterly l.c. and smith a.g., ind. eng. chem., 43 (9), 2125 – 2129 (1951). 16. lakshmi d.s., krishna m.r., pet. science and tech., 15 (7-8), 685-697, 1997. 17. kunert, maximilian, wegner and hans-georg, u. s. patent, 3945912, 1976. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.20 no.2 (june 2019) 61 – 69 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: ibrahim saeb salih , email: i.s_salih@hotmail.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. development of a semi-analytical type curve of transient pressure response in complex well-reservoir architectures ibrahim saeb salih and hussain ali baker petroleum engineering department/ college of engineering/ university of baghdad abstract the objective of the conventional well testing technique is to evaluate wellreservoir interaction through determining the flow capacity and well potential on a short-term basis by relying on the transient pressure response methodology. the well testing analysis is a major input to the reservoir simulation model to validate the near wellbore characteristics and update the variables that are normally function of time such as skin, permeability and productivity multipliers. well test analysis models are normally built on analytical approaches with fundamental physical of homogenous media with line source solution. many developments in the last decade were made to increase the resolution of transient response derivation to meet the complexity of well and flow media. semi-analytical modeling for the pressure transient response in complex well architecture and complex reservoirs were adopted in this research. the semi analytical solution was based on coupling the boundary condition of source function to the well segment. coupling well-reservoir on sliced based technique was used to re-produce homogenous isotropic media from several source functions of different properties. the approach can model different well geometries penetrated complex reservoirs. a computer package was prepared to model the pressure transient response of horizontal, dual-lateral, multi-lateral wells in complex anisotropic reservoirs, multilayered, compartmentalized, system of various boundary conditions such as: bottom support aquifers, edge supported, gas caps, interference of injection. the validity of the proposed model was successfully checked by using the commercial simulator. keywords: semi-analytical, pressure transient, multilateral wells. received on 01/10/2018, accepted on 20/03/2019, published on 30/06/1029 https://doi.org/10.31699/ijcpe.2019.2.8 1introduction both analytical and numerical approaches were implemented in a new technique to step away from the approximation in the finite difference and from the long calculations of green’s function ‎[1] in the solution of bem (boundary element method) ‎[2] multi-function domain response. the propose methodology is to proceed with solution of three dimensional partial differential equation in laplace space. the laplace space equation is solved by applying the stehfest algorithm ‎[3]. the solution is for point source ‎[4], integrate the solution over the wellbore length to estimate the transient well index over time ‎[5], ‎[6], ‎[7]. the boundary condition was modeled in the finite element method of a single domain with boundary conditions that identified in a three-dimensional perspective. hence, the solution comes to be similar to an infinite conductivity solution with mixed boundary conditions ‎[8]. ouyang ‎[9] and kabir ‎[10] solutions were used in this study for modeling the finite conductive wells to estimate pressure drop in pipes. the pressure drop for the wellbore segments was estimated ‎[11], which simultaneously integrated with the boundary conditions and with the infinite conductive solution to determine the influx rate per segment and the pressure drop from the toe to the junction point with the main bore. the newly proposed technique in this study is similar to that discussed by yildiz ‎[12], ouyang ‎[9], and archer ‎[6]. however, this technique does not take into account the lateral heterogeneity resolution across the drilled sections. this limitation is considered an advantage when modeling drainage area effective properties using the pressure transient response. in pressure transient analysis, the analytical and semi analytical analyses are normally taking into consideration the effective permeability and the effective well length as compensative parameters for the heterogeneity. however, it is not possible to determine the permeability profile across the drilled sections. it is convenient to use the finite difference simulators to determine the permeability profile where petrophysical information are usually integrated with well testing data for upgrading the model and with the fine grid distribution across the well to reduce the uncertainty. https://doi.org/10.31699/ijcpe.2019.2.8 i. s. salih and h. a. baker / iraqi journal of chemical and petroleum engineering 20,2 (2019) 61 69 26 the objective of this work: 1generate a simple algorithm for determining pressure response for the following conditions: a. complex wells of multiple drain holes that have different properties b. model boundary conditions of different types and its effect on the lateral productivity over time for instance; bottom support aquifers ( strong and weak support), gas cap energy ( strong and weak support), edge water drive (strong and weak ) for different sides, wells interference including injection support. compartmentalized reservoirs of different characteristics and different pressure baffles, and multi layered reservoir with different pressure gradients c. modeling and identification of drain holes cross flow phenomena d. design and optimize laterals deviation and length to maximize the well potential e. create a tool that can have great support on finite difference simulators history matching by identifying the drain holes main parameters from the pressure response model. 2validate the model approach across commercial computer packages (semi-analytical and finite difference) 3develop a computer package program with python language to simulate and produce pressure response 4extend the solution to perform rate transient analysis as well as the pressure transient analysis 2mathematical work a new approach has been used in this study to determine the transient pressure drop which can be categorized into three solution stages a. fluid flow towards the well segments : this part covers numerical inversion of point source laplace space solution of diffusivity equation b. formulation of the boundary type: this part covers the type of boundary conditions supporting the drainage region which is solved with a finite difference. c. pressure drop across the wellbore: this part is to determine the pressure drop among adjacent point source functions in the borehole and connect them up to the multilateral junction point. the first section of the mathematical development of the approach considers a small slab of the horizontal sink (fig. 1) as line source coupled with several numbers of similar conditions towards the main bore. fig. 1. schematic unit porous system ‎[12] the source function as illustrated above is for a segment of the total inflow length where its sink in permeable media. the solution of the diffusivity equation for this body, that representing the three-dimensional diffusivity equation, which will be solved for a single-phase slightly compressible fluid. the flow is converged to the unit length of the pipe as line source. the dimensions (xe, ye, ze) represent the drainage area dimensions (domain x, y, z) of the inflow segment. the reason is to model a homogenous representation of the effective well drainage area. the boundary type formulation represents the forces applied on the drainage domain in (x, y, and z) as shown in fig. 2. fig. 2. schematic boundary condition [12] the boundary type represented the type of forces that applied on each side of the domain. the various types such as water drive, gas cap, or injection influence can be represented through the definition of the initial boundary pressure support per side, such as: volumetric, constant, or gradients. the third part is to control the influx per inflow segment. the finite conductive approach is to integrate the pressure drop of entire segments for determining the influx rate per unit length. additionally, it used to cooperate the multilateral segments into an operating point to revolve the fluid flow dynamics on the network. fig. 3. i. s. salih and h. a. baker / iraqi journal of chemical and petroleum engineering 20,2 (2019) 61 69 26 fig. 3. schematic multilateral well a. fluid flow to source function the diffusivity equation normally governs the fluid flow in permeable media. the diffusivity equation is derived from the darcy equation and the mass balance equation. the general form of the diffusivity is [12] → (1) the general solution for the infinite conductive segment in the infinite reservoir is represented below in laplace space to resolve the short and long-term approximation of pressure [6] [7] [9]. (| | ) √ [∫ ( ) ∫ ( ) √ ( ) √ ( ) ] ∑ [ ( | |√ ) ( | |√ )] √ ∑ √ { [√ ( ] [√ ( ]} (2) the main advantage of having the solution in laplace space is that it is easy to obtain the solutions in the time domain at any period regardless of the flow regime. in other words, the short and long time approximation of the pressure response can be determined using the same equation for short and long time functions. the primary objective of the solutions reported by medeiros et al [13] is to define the source function of flow in laplace space as a general solution that can be inversely transformed at all times (short and long) to determine the pressure values over time. in summary, the approach adopted is to ‎[13], ‎[14]: 1define the main flow equation in laplace space 2solve the flow equation with stehfest numerical laplace inversion at long and short times, 3compare the results with the reported asymptotic formulas 4validate the laplace numerical inversion outputs at short and long times 5perform pressure solution at given times to determine flowing pressure at the well segments (source function) for infinite acting reservoirs with no inner and outer boundary conditions. b. reservoir fluid flow model the source function that defined previously represents the fluid flow from an infinite acting reservoir to the infinite conductive horizontal segment. the boundary type that affects the reservoir pressure over time of production requires separate modeling to adjust the depletion rate on the productivity of the well ‎[5]. the determination of boundary pressure was calculated using the finite difference approximation for a single grid block with homogenous anisotropic properties at each time step. this approach is efficient in well testing data interpretation due to the complexity of multi-well multireservoir characteristic and with adding the heterogeneity. the derivative match can be misleading. in such a case, the variable will be consistent per each well that penetrates specific layer properties. the finite difference approximation can be expressed as ‎[7]: (3) from the derivation above ‎[7], the dimensions (δx, δy, δz) represents the same dimensions that defined for the source function derivation, which is the drainage volume. the reservoir pressure p(i,j,k) is the variable that represents the output of the calculations for each time step and then feeds into the source functions to determine p (x,y,z). the adjacent grids pressures are represented in terms of the boundary support. in the case of volumetric reservoir; their values are zeros. if a constant pressure boundary is supplied, their values will be fixed. if the boundary is supportive, the gradient pressure value will be used to represent the side and the magnitude of the pressure support. the well index in the finite difference approximation equation is the output of the solution of source function where it is ‎[7], ‎[15]: [ ( ) ] [ [ ( )] ] (4) where pd is the output of the solution of the source function after the numerical inverse of laplace equation, b, μ, k, h are input parameters. twi is the transient well index, which is fed to the finite difference equation to determine reservoir pressure at time step n-1, twi is used at time step n in summary, the procedure used for determining the boundary pressure used is ‎[7]: 1the dimensionless pressure values are defined for each time step. 2the transient well index is calculated from the dimensionless pressure group 3the reservoir pressure, influx rate, and borehole pressure are key parameters to estimate the reservoir pressure at each using the finite difference approximation with the appropriate boundary type. i. s. salih and h. a. baker / iraqi journal of chemical and petroleum engineering 20,2 (2019) 61 69 26 4the well index is used to determine the reservoir pressure at time step n in order to calculate the reservoir pressure at time step n-1 5the remaining variables to be determined are the borehole pressure and rate. this will be resolved simultaneously with boundary pressure subject to the effect of reservoir pressure and well index per each time step keeping constant junction pressure. c. pressure and rate solution a reservoir-well coupling model needs to be developed to link the reservoir pressure with the source function inflow index to wellbore pressure drop at each time step. many researchers have been investigated the impact of inflow on pressure drop in addition to pipe flow gradient. ouyang and aziz ‎[9] presented a general equation to determine the pressure drop in inflow borehole, which was validated by the stanford laboratory experiment ‎[11]. the pressure drop along the inflow section with the mass transfer is (5) where τ is the shear friction, θ is the pipe inclination, al is the cross sectional area in the inflow segments, and ql is the segment inflow volumetric flow rate, u is the velocity, and γ is the inflow angle that represents the inclination between pipe and inflow direction. the equation (5) defines four different pressure drop components: friction, gravity, accelerations due to inflow, and inflow direction. the pressure drop in the inflow segment can be represented by the equation ( ) (6) where rw is the flow resistance in the wellbore segment and qw(x) is the flow rate at point x in the well segment the interdependent mechanisms for the wellbore segment flow are ‎[16], ‎[9]:  boundary layer effect: it is the change of thevelocity profile near borehole wall due to the inflow  kinetic energy effect: it is the additional acceleration added to the flow in the pipe due to inflow segments  inflow directional effect: it is the energy loss or increment due to the relation of the inflow direction to the axial pipe flow angle and direction. the dynamics of friction factor due to inflow have been studied previously where the no-flow pipe fanning friction factor does not represent the many forces that cause friction and pressure losses in inflow segments. the inflow causes an increment of dynamic friction component when laminar flows exist. in contrast, the inflow causes a reduction of friction when the flow is turbulent. the friction forces changes compared to flow dynamics. therefore, the friction factor calculations cannot be used for pipe flow without inflow. the procedure to determine the reservoir inflow by knowing the transient productivity index and the reservoir pressure at each time step is as follow: 1for a specific heel pressure. assume the pressure at the well toe 2divide the well into segments of specific resolution ratio 3determine the flow for the first segment from the assumed pressure at toe [ [ ] ] (7) 4determine the friction component for the specified rate. calculate the axial velocity, reynold number and dynamic friction factors as per the flow pattern 5determine pressure drop per segment for specified flow rate, move to the next inflow segment, with starting pressure as the assumed pressure at well toe subtracted from the pressure drop of the first segment. 6calculate the flow rate for the second segment and sum with the previous rate to have cumulative rate flow part of mass transfer. 7complete the process to reach the pressure at the heel of the well 8perform iterative calculation to determine the actual pressure at toe that matches the gradient to pressure at the well heel. 9the output will be the pressure profile from the toe to heel with the production profile of the well. 10for multi-lateral, wells, matrix solution to the junction pressure in the iterative procedure (newton-raphson method) to resolve the production rate per each lateral for each inflow zone up to the well junction. 11the rate calculation using such procedure was implemented on purpose to determine the operative junction pressure with maximum production without cross flow depicted between lateral. fig. 4 illustrates the points mentioned above. fig. 4. illustration of the iterative pressure drop computation ‎[9] i. s. salih and h. a. baker / iraqi journal of chemical and petroleum engineering 20,2 (2019) 61 69 26 python code was developed in this study to solve the series of steps explained. figure 5 represents the software architecture fig. 5. conceptual schematic of python code 3results and discussion three main cases have been conducted in this study to illustrate the capabilities of the proposed model. these cases are: a. case 1 dual lateral well in anisotropic homogenous reservoirs with a volumetric boundary type the first case is a short radius dual lateral in a single layer of homogenous anisotropic properties. the input data is illustrated in figure 6 and tabulated in table 1. fig. 6. case 1 schematic table 1. case 1 input data the performance capacity of the proposed model in predicting the pressure response has also been checked with commercial computer simulator. the pressure response and the pressure log-log plot are shown in fig. 7 and fig. 8. fig. 7. bottom hole pressure calculation against simulator results the separation in pressure values is constant, around 30 psi on average, the difference is justified by the wellreservoir coupling as the commercial software model assume infinite conductive drain holes while the proposed model takes into account the extra pressure drop happens that in the wellbore which is most significant in the early transient time. lateral 1 lateral 2 unit rw 0.1 0.1 ft h ft phi b eccentricity mu ct 1/psi pi psi kx md ky md kz md skin 0 0 inflow section length 100 100 ft total horizontal section 1000 1000 ft deviated section 100 100 ft cureture angle 40 40 degree vertical section to junction 50 50 ft 0.5 10 10 1 100 0.2 1 1 5.00e-05 5000 i. s. salih and h. a. baker / iraqi journal of chemical and petroleum engineering 20,2 (2019) 61 69 22 fig. 8. pressure drop and derivative log -log plot in comparison with simulated data the pressure derivative is a function to reservoir response regardless of the wellbore pressure as the plot takes the pressure difference but not the absolute values. the radial flow stabilization in late time in the model data can be attributed to the data-smoothing algorithm in the commercial software, which is not taken into consideration in the proposed model. b. case 2 multi-layer reservoir anisotropic heterogeneous penetrated by dual lateral of different drain hole information. the reservoir lower layer has the bottom water drive boundary type. the second case is more complicated dual lateral than the first case. a multi-layer system has been introduced with the stacked dual lateral of different elevation for the junction point. the reservoir characteristics are different. the upper layer is closed with the lower layer has a bottom water drive. the well schematic displayed in fig. 9 and information of inputs is grouped in table 2. fig. 9. case 2 schematic table 2. case 2 input data the pressure drop in each lateral section is not equal which causes different rate contribution per lateral, the pressure response as shown in fig. 10. fig. 10. bottom hole pressure calculation against simulator results the deviation in the bottom hole pressure is only 20 psi compared with the commercial simulator. the pressure log-log plot for the model data and the simulator data is shown in fig. 11. fig. 11. pressure drop and derivative log log plot in comparison with simulated data lateral 1 lateral 2 unit rw 0.1 0.1 ft h 30 70 ft phi 0.25 0.15 b 1.2 1.2 eccentricity 0.3 0.7 mu 3 3 ct 1.00e-06 1.00e-06 1/psi pi 5000 5000 psi kx 100 70 md ky 50 20 md kz 10 1 md skin 0 0 inflow section length 500 1000 ft total horizontal section 1000 1500 ft deviated section 200 400 ft cureture angle 40 40 degree vertical section to junction 50 150 ft i. s. salih and h. a. baker / iraqi journal of chemical and petroleum engineering 20,2 (2019) 61 69 26 the slight mismatch in the intermediate linear flow in figure (11) is due to the extra pressure drop representation of the wellbore as a pseudo skin, which is the main difference between finite and infinite conductive wells. c. case 3 quadrilateral well drilled in four different heterogamous layers of different boundary conditions, two layers under the gas cap, one layer with edge water drive and the fourth is volumetric the case is a multi-layer system with four branched well of different lengths and elevations from the junction point. the reservoirs characteristics are different in terms of porosity, permeability, and fluid properties. four layers with the different boundary conditions, all relevant information of the third case displayed in table 3. the well schematic is shown in fig. 12. fig. 12. schematic of case 3 table 3. case 3 input data the pressure response as below: fig. 13. comparison of pressure drop between simulator and model the deviation in the bottom hole pressure is only 350 psi compared with the commercial simulator, while by comparing model results with the finite difference model for segmented wellbore coupling the difference is less than 50 psi. the pressure log-log plot for the model data and the simulator data is below. fig. 14. log –log plot comparing model results versus simulator data 4conclusions the conclusions with regards the semi-analytical solution that has been done in this study are listed below: 1due to the analytical nature of the solution, more resolution and accuracy are expected if they are compared with the full numerical approach. 2the results were in good agreement with the commercial simulators in predicting the pressure drop of a reservoir and through the borehole (for the finite conductive approximation). 3when modeling the wells as infinite conductive, the error in pressure drop is less than 10%. however, the lateral 1 lateral 2 lateral 3 lateral 4 unit rw 0.3 0.3 0.3 0.3 ft h 10 30 15 45 ft dx 5000 7000 3000 100000 dy 5000 70000 100000 100000 phi 0.2 0.25 0.1 0.2 b 1 1 1 1 eccentricity 0.5 0.8 0.1 0.5 mu 1 1 1 1 ct 1.00e-06 1.00e-06 1.00e-06 1.00e-06 1/psi pi 3500 3800 4200 5000 psi kx 200 50 300 10 md ky 200 50 300 10 md kz 200 0.5 60 5 md skin -2 -4 2 -3 inflow section length 500 1000 300 1500 ft total horizontal section 500 1000 300 1500 ft deviated section 200 200 200 200 ft cureture angle 40 40 40 40 degree vertical section to junction 50 50 50 50 ft boundary conditions gas cap gas cap volumetric edge water drive i. s. salih and h. a. baker / iraqi journal of chemical and petroleum engineering 20,2 (2019) 61 69 28 error percent is subjected to the ratio of pressure drop in the reservoir to pressure drops in the well. 4the pressure derivative response was very well matching the laterals and layers response, i.e, the transient state was well captured to determine the effective system properties (skin components, effective layers permeabilities, and pressure baffles) 5productivity indices per lateral were adequately matching the commercial simulator modeled inputs. recommendations the following are the limitations of the current study, which can be discussed, in future work 1multiphase was not included in the calculation and all flows in the reservoir and well is single phase. 2injection frontal advance was not included in calculation and injector support considered by pressure rate influx of it produced phase. 3instead of using stehfest algorithm for laplace numerical inversion, fourier numerical inversion can be used in future researches. 4the pressure drop effect in pipes does not take into account the acceleration component in the horizontal section, which is assumed fully horizontal with no change in elevation. multilayer production from single wellbore was not taken into consideration and each lateral in single layer model, however, internal multilayer cross flow was studied nomenclature ⃗⃗ : permeability tensor (three dimensional matrix value) : pressure gradient in three dimensions : porosity : viscosity : compressibility : directional permeability (i=x,y,z) : dimensionless time : dimensionless x direction drainage region length : dimensionless y direction drainage region length : dimensionless z direction drainage region length : dimensionless well length : effective permeability (geometrical or horizontal based on vertical permeability effect on flow regime) : reservoir pressure ( ) : pressure at any point and time in borehole. : dimensionless borehole elevation in the reservoir ( ) : dimensionless pressure drop at any point and time ̅̅̅̅ : dimensionless pressure drop in laplace domain : constant : dimensionless wellbore radius : bessel function roots : dimensionless z direction drainage region length : dimensionless well length ( ) pressure drop due to flow convergence – convergence skin ( ) horizontal well radial pseudo skin factor references [1] barreto a., a. peres and a. pires, "variable-rate solution to the nonlinear diffusivity gas equation by use of greens-function method," spe reservoir evaluation & engineering, vol. 18, no. 01, pp. 57 68, 2012, december 28. [2] yang c. and k. j. john, "an improved boundary element method for modeling fluid flow through fractured porous medium," in spe reservoir simulation conference, montgomery, texas, usa, 20-22 february, 2017. [3] al-ajmi m., m. ahmadi, e. ozkan and h. kazemi, "numerical inversion of laplace transforms in the solution of transient flow problems with discontinuities," in spe annual technical conference and exhibition, denver, colorado, usa, 21-24 september,2008. [4] lu j., cunha l. b. and lu t., "new solutions for well test analysis of horizontal wells," in spe international thermal operations and heavy oil symposium and international horizontal well technology conference, calgary, alberta, canada, 47 november,2002. [5] archer r. and yildiz t., "transient well index for numerical well test analysis," in spe annual technical conference and exhibition, new orleans, louisiana, 30 september-3 october,2001. [6] archer r. and horne r., "the green element method for numerical well test analysis," in spe annual technical conference and exhibition, dallas, texas, 1-4 october, 2000. [7] aguilar c., ozkan e., h. kazemi, m. al-kobaisi and b. a. ramirez, "transient behavior of multilateral wells in numerical models: a hybrid analyticalnumerical approach," in spe middle east oil and gas show and conference, manama, bahrain, 11-14 march, 2007. [8] dennis denney (jpt technology editor), "analytical/numerical hybrid models for horizontalwell transient tests," journal of petroleum technology, vol. 53, no. 07, pp. 58 59, 2001. [9] ouyang l. and aziz k. , "a simplified approach to couple wellbore flow and reservoir inflow for arbitrary well configurations," in spe annual technical conference and exhibition, new orleans, louisiana, 27-30 september,1998. [10] kabir h. and gerardo a. , "accurate inflow profile prediction of horizontal wells through coupling of a reservoir and a wellbore simulator," in spe reservoir simulation symposium, the woodlands, texas, 2-4 february, 2009. [11] aziz k.(stanford u.), "a general single-phase wellbore/reservoir coupling model for multilateral wells," spe reservoir evaluation & engineering, vol. 4, no. 04, pp. 327 335, 2001. [12] yildiz t., "multilateral pressure-transient response," spe journal, vol. 8, no. 01, pp. 5-12, 2003. https://doi.org/10.2118/145468-pa https://doi.org/10.2118/145468-pa https://doi.org/10.2118/145468-pa https://doi.org/10.2118/145468-pa https://doi.org/10.2118/145468-pa https://doi.org/10.2118/182658-ms https://doi.org/10.2118/182658-ms https://doi.org/10.2118/182658-ms https://doi.org/10.2118/182658-ms https://doi.org/10.2118/182658-ms https://doi.org/10.2118/116255-ms https://doi.org/10.2118/116255-ms https://doi.org/10.2118/116255-ms https://doi.org/10.2118/116255-ms https://doi.org/10.2118/116255-ms https://doi.org/10.2118/116255-ms https://doi.org/10.2118/78972-ms https://doi.org/10.2118/78972-ms https://doi.org/10.2118/78972-ms https://doi.org/10.2118/78972-ms https://doi.org/10.2118/78972-ms https://doi.org/10.2118/78972-ms https://doi.org/10.2118/71572-ms https://doi.org/10.2118/71572-ms https://doi.org/10.2118/71572-ms https://doi.org/10.2118/71572-ms https://doi.org/10.2118/62916-ms https://doi.org/10.2118/62916-ms https://doi.org/10.2118/62916-ms https://doi.org/10.2118/62916-ms https://doi.org/10.2118/104581-ms https://doi.org/10.2118/104581-ms https://doi.org/10.2118/104581-ms https://doi.org/10.2118/104581-ms https://doi.org/10.2118/104581-ms https://doi.org/10.2118/104581-ms https://doi.org/10.2118/0701-0058-jpt https://doi.org/10.2118/0701-0058-jpt https://doi.org/10.2118/0701-0058-jpt https://doi.org/10.2118/0701-0058-jpt https://doi.org/10.2118/48936-ms https://doi.org/10.2118/48936-ms https://doi.org/10.2118/48936-ms https://doi.org/10.2118/48936-ms https://doi.org/10.2118/48936-ms https://doi.org/10.2118/119095-ms https://doi.org/10.2118/119095-ms https://doi.org/10.2118/119095-ms https://doi.org/10.2118/119095-ms https://doi.org/10.2118/119095-ms https://doi.org/10.2118/72467-pa https://doi.org/10.2118/72467-pa https://doi.org/10.2118/72467-pa https://doi.org/10.2118/72467-pa https://doi.org/10.2118/65479-ms https://doi.org/10.2118/65479-ms https://doi.org/10.2118/65479-ms i. s. salih and h. a. baker / iraqi journal of chemical and petroleum engineering 20,2 (2019) 61 69 26 [13] medeiros f., ozkan e.and kazemi h., "a semianalytical, pressure-transient model for horizontal and multilateral wells in composite, layered, and compartmentalized reservoirs," in spe annual technical conference and exhibition, san antonio, texas, usa, 24-27 september,2006. [14] king m., wang z. and datta-gupta a., "asymptotic solutions of the diffusivity equation and their applications," in spe europec featured at 78th eage conference and exhibition, vienna, austria, 2016, may 30. [15] m. al-jawad and m. abdulrazaq, “calculating production rate of each branch of a multilateral well using multi-segment well model: field example”, eng. j., vol. 23, no. 11, pp. 70-80, nov. 2017. https://iasj.net/iasj?func=fulltext&aid=132614 [16] ghanim m. farman and maha raouf abdulamir, “formulation of new equation to estimate productivity index of horizontal wells” iraqi journal of chemical and petroleum engineering , vol. 15, no. 2. تطوير موديل شبه تحميمي الستجابة الضغط العابر في اآلبار والمكامن المعقدة الخالصة اليدف من فحوصات الضغط االنتقالي التقميديو لالبار ىو لتقييم التوصيميو بين البئر والمكمن عن طريق بالسمك الفعال لمطبقو والنفاذيو الفعالو لممكمن باالضافو لحساب القابميو استحصال معامل التوصيميو المعرف االنتاجيو لمبئر. حسابات فحوصات الضغط االنتقالي ىو خطوه ميمو لتقييم المكامن النفطيو والغازيو وكذلك الضغط واالنتاج ادائيو االبار المنتجو وابار الحقن, وتعتبر نتائجو مدخل ميم لممحاكاه المكمنيو لمتنبؤ بيبوط المستقبميو. ىو أخذ مقاربة نموذج شبو تحميمي الستجابة الضغط العابر في بنية البئر المعقدة البحثاليدف من ىذه والخزانات المعقدة. الحل شبو التحميمي يعتمد عمى اقتران الشرط الحدودي لدالو المصدر بجزء البئر. مبدأ ربط المصدر النقطي بأخذ مقطع من المكمن والبئر وتحميمو ثم ربطو بالمقطع االخر البئر بالمكمن يعتمد عمى دالو عدديا بأخذ بنظر االعتبار ىبوط الضغط بالبئر بين مقطعين وىبوط ضغط المكمن. التقنية تستند إلى إعادة ل إنتاج الوسائط مجزئو متجانسة من عدة دوال مصدريو من خصائص مختمفة. يمكن محاكاه من ىذا المودي نماذج ىندسية مختمفة مخترقو المكامن المعقدة. تم صياغو برنامج محاكاه باستخدام لغو البرمجو بايثون أعدت لمتنبأ الستجابة الضغط لآلبار األفقية والثنائية والمتعددة األطراف في مكامن متباينة الخواص ومتعددة الطبقات ومجزأة وأنظمة ظروف حدودية مختمفة مثل: مياه الجوفية الداعمة لؤلسفل والحافة المدعومة وأغطية الغاز وتداخل الحقن . تم التحقق من النموذج طبقات ال برنامج محاكاة تجاري بالمقارنو مع .األطراف متعددة آبار ، االنتقالي الضغط ، تحميمية شبو: الدالة الكممات https://doi.org/10.2118/102834-ms https://doi.org/10.2118/102834-ms https://doi.org/10.2118/102834-ms https://doi.org/10.2118/102834-ms https://doi.org/10.2118/102834-ms https://doi.org/10.2118/102834-ms https://doi.org/10.2118/180149-ms https://doi.org/10.2118/180149-ms https://doi.org/10.2118/180149-ms https://doi.org/10.2118/180149-ms https://doi.org/10.2118/180149-ms http://joe.uobaghdad.edu.iq/index.php/main/article/view/363 http://joe.uobaghdad.edu.iq/index.php/main/article/view/363 http://joe.uobaghdad.edu.iq/index.php/main/article/view/363 http://joe.uobaghdad.edu.iq/index.php/main/article/view/363 http://joe.uobaghdad.edu.iq/index.php/main/article/view/363 https://iasj.net/iasj?func=fulltext&aid=132614 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/278 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/278 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/278 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/278 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/278 available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.20 no.3 (september 2019) 7 – 31 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: rusul f. abdul-saheb , email: rusul744@gmail.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. a comparative study of the influence of different types of polymers on viscosity index and pour point of iraqi base oils rusul f. abdul-saheb and muhanned a. mohammed al-nahrain university abstract in this study, the effects of blending the un-branched acrylate polymer known as poly (n-decyl acrylate), and the branched acrylate polymer known as poly (iso-octyl acrylate), on the viscosity index (vi), and the pour point of the iraqi base stocks 40, and 60 respectively, were investigated. toluene was used as a carrier solvent for both polymer types. the improvement level of oils (vi, & pour point) gained by blending the oil with the acrylate derived polymers was compared with the values of (vi, and pour point) gained by blending the oil with a commercial viscosity index, and pour point improver. the commercial lubricant additive was purchased and used by al-daura refineries. it consisted of an un-known olefin copolymer dissolved in an un-known carrier solvent. all polyacrylate derivatives and the commercial lubricant additive named hitec5748 were blended with each type of oil in weight percentage of (2, 4, 6, 8, & 10) wt. %. the result of the study was that the improvement in the viscosity index and the pour point of both base stock types was higher when using the polyacrylate derivatives than when using the commercial olefin copolymer additive. keywords: lubricants, viscosity index, pour point, pol acrylates received on 02/12/2018, accepted on 22/01/2019, published on 30/09/1029 https://doi.org/10.31699/ijcpe.2019.3.2 1introduction machines perform a window for the development of the world, because of their entry in wide fields of human life aspects including; transportation fields such as automobiles, and trains, power generation fields such as turbines, boilers, compressors, and many more other applications ‎[1]. machines during their usage suffer corrosion, tear, and friction forces leading to machine cracks, and system failures. as a result, the protection of machines against degradation became the main consideration, and the need for lubrication appeared ‎[2]. a lubricant can be defined as a substance utilized in smoothing the movement of solid bodies through decreasing friction, heat due to friction, and corrosion over the interacting surfaces, thus they prolong machine life period ‎[3]. lubrication itself is not a newly created concept, hundreds of years ago animal fats were used for the purpose of lubrication. the basic principle of lubrication is the prevention of metal-to-metal contact by introducing a fluid or fluid-like material layer known as a lubricant between the interacted surfaces ‎[4]. lubricants can be categorized according to their physical appearance in to liquid lubricants including the lubricants that are derived from petroleum oils, synthetic oils or from biological sources, semi-solid lubricants which are liquid suspended in a solid matrix of additives and thickener like greases, and solid lubricants which are films of solid material composed of organic or inorganic compounds like graphite ‎[5]. the present day commercial lubricants are combinations of base oils and additives. the base oil should pass through de-waxing, and solvent extraction processes prior to mixing with the additives, in order to reduce both wax and polyaromatic content. where wax prevents free movement at lower temperatures ‎[6], ‎[7], while polyaromatics reduce the stability of oils viscosity to temperature variation ‎[7].the additives are mostly organic compounds within special structures that are added to base oils in small quantities to upgrade their characteristic including viscosity, viscosity index, and pour point ‎[8]. the un-used lubricant contains from (71 to 96 wt. %) base oil, and the rest are additives ‎[9]. the viscosity of an oil is a major concern in selecting the proper lubricant for a given application, since it increases with temperature reduction, and reduces with temperature increasing. the value of viscosity should be high enough to ensure good lubrication but not very high so the friction losses are increased ‎[10]. the viscosity index (vi) is a calculated dimensionless number represents the sensitivity of oils viscosity to temperature, in other words, the vi represents oils viscosity change with temperature variation ‎[11]. higher vi number expresses low viscosity dependence on temperature which is preferred ‎[12]. viscosity index improvers (viis) are high molecular weight long chain oil soluble polymers that are added to lubricants to control their rate of viscosity variation with temperature. https://doi.org/10.31699/ijcpe.2019.3.2 r. f. abdul-saheb and m. a. mohammed / iraqi journal of chemical and petroleum engineering 20,3 (2019) 7 21 8 they have a small effect on lubricant consistency at low temperatures while their molecules transform from tight coils to an open configuration at higher temperatures thus, exerting a larger thickening influence on lubricant at higher temperatures than they do at lower temperatures ‎[13]. the pour point of the oil is the minimum temperature at which oil still can circulate; lower pour point oils are preferred. the formulation of crude oil derives contains waxes naturally. the wax molecules combine with each other and crystallize. furthermore, the wax crystals precipitate forming a gel material that restricts oil flow at low temperatures. the pour point depressants are added substances that lower the pour point of oil through meddling with wax crystallization ‎[14]. margareth et al. [2010] verified the effects of vi modifiers on the consistency of lubricants, also discussed fuels economics. 8 types of additives were examined in the study. they concluded that the multigrade viscosity fuels are better than the monograde viscosity fuels. it was also found that the fuel consumption increases linearly with lubricant high temperature, high shear viscosity, and lower friction power can be reached through using lower viscosity multigrade oil in motor operation ‎[15]. salah et al. [2012] produced and assessed six copolymers derived from polyacrylates to be used as lubricant additives for viscosity index improvement. the molecular weight of the produced polymers was calculated to have values between 140,000 and 236,000. blends of different weight fractions vary from 0.5% to 3%, for each copolymer was produced, then examined as lube oil vi improvers. they concluded that all produced materials were efficient lube oil vi improvers, and the effectiveness increases by increasing either their molecular weight or their alkyl chain length. the effectiveness could also be raised by raising the concentration of the additives in the base oil. there were no reflection points in the examined range of concentrations ‎[16]. joshua et al. [2016] prepared and evaluated the extremely branched polyethylene as the viscosity index, and friction improvers. the prepared materials proved a dual function. these compounds reduced the friction and the viscosity index of the lubricant. changing the molecular weight, polarity and topology of the branched polyethylene displayed respectable changes in lubricant performance. this study supported the future development of lubricants and the design of new scientific polymers ‎[17]. sheida et al. [2016] studied the possibility of improving the properties of lubricants that are mainly manufactured from crude oils or from synthetic hydrocarbon mixes by using nanoparticle additives. nanoparticles are added to the base stock to enhance many characteristics of anti-oxidation probability, tribological properties, wear and friction resistance and thermal characteristics. this research shows studies on nano-additives in the industry of lubricants. the study includes both general view on base oils and traditional lubricants modifiers and a more specific view on the employment of nano-particles. in the end, this research has big benefits for the future use of nanoparticles in the lube oil industry ‎[18]. neveu et al. [2016] this article is a general overview of poly alkyl methacrylates (pama), including their manufacturing pathway to the economics of their usage in lubrication fields ‎[19]. mohammad et al. [2018] investigated the rheological attitude of nano-lubricants containing (sio2/5w50). the nano-lubricant consisted of 40% mwcnt, and 60% sio2/5w50 nanoparticles. the dynamic consistency of lubricant was determined for temperature domain between 5 °c and 55°c, the additive volume % was between 0, and 1, and the average shear of the fluid varied from 50 to 800 rpm. the study of nano fluids rheological attitude against its shear stress proved that the nano-lubricant is a nonnewtonian fluid that follows bingham shear thinning behavior for low temperatures while the behavior is turned at high temperatures. a correlation for relative dynamic viscosity estimation was proposed, and it showed a proper accuracy ‎[20]. the main purpose of this research is to develop the properties of lubricants, by using different additives. then to find the optimum weight fractions of each additive which enhance the properties of the lubricant such as, viscosity index, and pour point. 2experimental work 2.1. materials and chemicals a. the iraqi base-stock the two types of base stock were obtained from aldaura refineries, as products for the vacuum distillation process. the properties of base oils are shown in table 1. table 1. the used iraqi base stocks, and their characteristics property basestock 40 basestock 40 kinematic viscosity at 40 °c, cst 14.2 63.4 kinematic viscosity at 100 °c, cst 3.36 8.5 viscosity index (vi) 106 108 specific gravity at (15.6 °c / 15.6 °c) 0.85 0.88 api gravity 34.97 29.29 pour point, °c -9 -6 r. f. abdul-saheb and m. a. mohammed / iraqi journal of chemical and petroleum engineering 20,3 (2019) 7 21 9 b. chemicals the chemicals used were hitec5748 commercial olefin copolymer, in a liquid state, brown color, of 955 cst. 100 °c kinematic viscosity, and a shear stability index of 155(china), poly (n-decyl acrylate) a white powder with a purity of 95 %, and a density of 2.42 gm. / cm3 (china), poly (iso-octyl acrylate) a transparent powder with a purity of 98 %, and a density of 1.85 gm. / cm3 (china), and toluene, liquid with a vapor pressure of 22 mmhg, and 99.8 purity (china). 2.2. analysis instruments a. kinematic viscosity equipment the tamson tv4000 equipment is designed to determine the kinematic viscosity of blends at steady temperatures according to the astm d445 test method. the instrument consists of a transparent glass viscometer and a controlled temperature oil bath. the viscometer is a simple apparatus valid in different shapes, and sizes. their selection depends upon the viscosity of the liquid, more viscous liquids requires wider viscometers. the bath chamber is made of stainless steel with one transparent glass window. the machine temperature range varies from 10° c to 230° c with an accuracy of ± 0.1° c. the device contains eight holes for subjecting viscometer holders. the working voltage of the instrument is 230 v. b. pour point tester this instrument works like a refrigerator; it reduces the temperature of the sample to estimate their freezing temperatures for pour point measurement according to astm d97 test method. the apparatus model is hamco cloud and pour point apparatus. the device temperature range varies from zero to -51°c, it has four jacket baths, and each one is preset at a different temperature for convenient pour point testing. bath hoods are covered with a synthetic sponge top plate. bath cabinet and interior housing are constructed of stainless steel with a removable top plate and 13mm cork. 2.3. experimental procedure a. the preparation steps of hitec5748 additive blends the used experimental instruments including (beakers, and viscometers) should be clean, dry, and at room temperature prior to their usage. the weight of the beaker was measured by using a sensitive balance, since the beaker is only a container, and its weight should be neglected during the preparation of samples. then the additive was introduced into the beaker for the desired wt. %, the base oil was introduced into the beaker after. the beaker that contains both base oil and additive was then adjusted over a hot plate magnetic stir to get homogeneous liquid blends of base-stock and polymeric additives. the samples were blended for 40 minutes at a temperature of 70°c. the well-mixed samples are allowed to settle, and to get to room temperature before examining the effects of the additive on the vi, and pour point of the oil according to the astm test methods procedures. b. the preparation steps of poly (n-decyl acrylate), and poly (iso-octyl acrylate) additives blends both poly (n-decyl acrylate), and poly (iso-octyl acrylate) additives were dissolved in toluene in order to make them in liquid form before blending them with the oils. each additive was mixed with the toluene in weight percentage of 60 % polymer, and 40 % solvent separately. the mixture was then adjusted over a hot plate magnetic stir for a period of 4 hr. at a temperature of 60 ° c. the prepared mixtures were left at room temperature for many days to ensure their solubility, where no precipitates or impurities appeared. after the solubility and homogeneity of mixtures were checked, the solutions were blended with base oil following the same steps of hitec5748 additive mentioned in (2.3.a) section. 3results, and discussion 3.1. effect of hitec5748 additive this olefin copolymer was selected to be a reference additive to evaluate acrylate derived polymers efficiency as vi, and pour point improvers. fig. 1 observes the effect of hitec5748 addition on the vi of base stock 40, and 60 respectively. the behavior of both base stocks is the same that is increasing the wt. % of additive leads to an increase in vi. the olefin copolymer molecules are arranged to stay as tight coils at low temperatures so that, there presence doesn’t affect the viscosity of oil. while at high temperatures, their presence doesn’t affect the viscosity of the oil. while at high temperatures their molecules expand forming open configurations that raise the viscosity of the oil ‎[21]. the vi represents the stability of oils viscosity against temperature change. the higher the vi value gained is better since, it indicates low sensitivity to temperature change ‎[22]. the vi of base stock 40 is more affected by the presence of hitec5748 than base stock 60 due to the difference in the viscosity between base 40, and base 60 where, lower viscosity stock is better since, lower viscosity values reached at cold conditions which are an essential requirement, also more fluidity means more capability of olefin to extend at higher temperatures ‎[23]. the obtained mixtures are suitable to be used as motor lubricants where vi is sufficient to establish lubrication also the formed mixtures have good fluidity. r. f. abdul-saheb and m. a. mohammed / iraqi journal of chemical and petroleum engineering 20,3 (2019) 7 21 01 fig. 1. effect of hitec5748 on the vi of stocks 40 & 60 fig. 2 observes the effect of hitec5748 addition on the pour point of base stock 40, and 60 respectively. the figure shows that both stock types are affected by the addition of hitec5748 olefin copolymer only there behaviors against it are different. where the pour point of base stock 40 reduces by the addition of copolymer and reaches its minimum value of 21 at 2 wt. % of the additive, the molecules of additive combine with the wax molecules that are already present in mineral base oils and suspend these combinations in the bulk fluid, which restricts the formulation of big wax crystals leading in the end to the reduction in the pour point ‎[11], ‎[24]. at 4 wt. % the behavior of base stock 40 is reflected since, increasing the wt. % of additive causes an increase in the pour point, this inversion is attributed to the increase in the molecular weight of the additive, density of additive, and viscosity of the blends by the addition of the olefin i.e. the saturation with the additive occurs, leading to pour point increasing as a result which is not favorable ‎[24]. while for base stock 60, the pour point keeps reducing by the addition of hitec5748 copolymer, and it reaches its minimum value of -12 at 8 wt. % of the additive. there was no inversion noticed in this case, because lower viscosity oils are more affected by the action of additives ‎[23]. economically, the base stock 40 is better than base stock 60 because lower pour points can be earned with fewer amounts of additive. fig. 2. effect of hitec5748 on the pour point of stocks 40 & 60 3.2. effect of poly (n-decyl) acrylate additive fig. 3 observes the effect of poly (n-decyl acrylate) addition on the vi of base stock 40, and 60 respectively. in general, vi increased with wt. % increase. this increase in vi is attributed to the structure of the additive, where it belongs to the poly alkyl methacrylate (pama) family. the molecules of this family members are hydrocarbons that have the ability to extend forming big size arrangements that raise the viscosity of the oil at higher temperatures i.e. increase the stability of oil viscosity against temperature change ‎[25], ‎[26]. the vi increased from 108 to 186 for base stock 40, while increased from 106 to 142 for base stock 60. the base stock 40 is more affected by the presence of poly (ndecyl acrylate) than base stock 60. this difference between vi readings is because of the difference in the viscosity of base stocks, since lower viscosity sample is a more suitable environment for viscosity index improvers ‎[23]. the increasing manner in the viscosity index of both base stock types 40, and 60 after the addition of poly (ndecyl acrylate) copolymer is similar to the vi increasing manner of hitec5748 olefin copolymer additive, but the vi values are higher. this difference in vi is because of the presence of ester functional group in the structure of the monomers that form the poly (n-decyl acrylate) copolymer, which categorized to be more active than the double bond carbon atoms contained in the monomers of the commercial olefin copolymer ‎[26]. the obtained mixtures properties are acceptable in motor lubricants where vi is sufficient to establish lubrication also the formed mixtures have good fluidity. fig. 3. effect of poly (n-decyl acrylate) copolymer on the vi of stocks 40 & 60 fig. 4 shows the effect of poly (n-decyl acrylate) addition on the pour point of base stock 40, and 60 respectively. the figure shows that both stock types are affected by the addition of poly (n-decyl acrylate) copolymer. the pour point of base stock 40 reduced by the addition of poly (n-decyl) acrylate copolymer and reached its minimum value of -24 at 10 wt. %. r. f. abdul-saheb and m. a. mohammed / iraqi journal of chemical and petroleum engineering 20,3 (2019) 7 21 00 while for base stock 60, the pour point reduced by the addition of copolymer and reached a minimum value of 15 at 6 wt. % of the additive, then the pour point remains fixed (-15) against the further addition of the additive due to the saturation of base oil with the additive where its effect reached the maximum possible dispersing efficiency. the copolymer can be described as an efficient pour point dispersant since, it combines with the soot and wax molecules presented in base stock, and keeps them suspended in the bulk fluid, which interferes the formulation and precipitation of wax crystals network that absorbs lubricant and forms gelling in the oil, leading in the end to increase the fluidity of oil, and reduction in pour point value ‎[27]. it can be concluded that for the pour point, the response to poly (n-decyl acrylate) of base stock 40 is greater than that of base stock 60 since, the lower viscosity oil has more fluidity and reaches lower temperatures before getting freeze than the viscous one ‎[23]. economically, the base stock 40 is better than base stock 60 because lower pour points can be earned with fewer amounts of additive. fig. 4. effect of poly (n-decyl acrylate) copolymer on the pour point of stocks 40 & 60 3.3. effect of poly (iso-octyl acrylate) additive fig. 5 displays the effect of poly (iso-octyl acrylate) addition on the vi of base stock 40, and 60 respectively. the vi of both base oils increased with additive wt. % increase. this increase in vi is attributed to the considerable thermal stability of the poly (iso-octyl acrylate) copolymer, and its resistance for thermal degradation, thus increasing this copolymer concentration in the base oil reduces oils sensitivity to temperature change [25]. by the addition of poly (iso-octyl acrylate) copolymer, the vi increased from 108 to 200 for base stock 40, while increased from106 to 150 for base stock 60. the base stock 40 is more affected by the presence of the additive than stock 60, following the same behavior of [hitec5748, and poly (n-decyl acrylate)] additives. the viscosity difference between base oils is the reason for the gained vi difference. lower viscosity base oil is more suitable to assist the vi improver to work [20], and since the base stock 40 has a lower viscosity than base stock 60, it was already expected to have higher vi values when being mixed with the suitable additive. the viscosity index of both base stock types 40, and 60 increase after the addition of poly (iso-octyl acrylate) copolymer in a manner close to poly (n-decyl acrylate) copolymer additive, only with higher vi values. this difference in vi is because of the difference in the structure between the two additives where the monomers of poly (iso-octyl acrylate) copolymer are branched hydrocarbons with ester functional group. the branched hydrocarbon chains increase the capability of a polymer to improve the vi of an oil, due to their ability to expand forming big size structures that fill the bulk fluid at higher temperatures ‎[27]. the obtained mixtures properties are acceptable in motor lubricants where vi is sufficient to establish lubrication also the formed mixtures have good fluidity. fig. 5. effect of poly (iso-octyl acrylate) copolymer on the vi of stocks 40 & 60 fig. 6 shows the effect of poly (iso-octyl acrylate) addition on the pour point of base stock 40, and 60 respectively. the figure shows that both stock types are affected by the addition of copolymer whrer, the pour point reduced with wt.% increase. the reduction in the value of pour point is attributed to the structure of the monomers that form the poly (isooctyl acrylate) copolymer. the monomers consist of a hydrocarbon part that combines with the impurities (soot, wax, combustion products), and a non-pollar ester part that keeps those impurities suspended in the bulk base stock, leading to the increase in the fluidity of oil at lower temperatures i.e. reduction in the pour point of the oil ‎[28]. the pour point of base stock 40 reduced with the addition of poly (iso-octyl acrylate) copolymer and keeps reducing as the wt. % increases. r. f. abdul-saheb and m. a. mohammed / iraqi journal of chemical and petroleum engineering 20,3 (2019) 7 21 01 it reached a minimum value of -27 at 8 wt. % of the additive, then the additive efficiency as a pour point dispersant reduces at 10 wt. % of copolymer since, the pour point increased to -24 due to oil saturation with an additive which reduced the fluidity, and increased the pour point as a result. while for base stock 60, the pour point reduced by the addition of copolymer and reached minimum value of -18 at 8 wt. % of the additive, then the pour point remains fixed (-18) against the further addition of the additive, the steady value of pour point also indicates saturation of oil with additive ‎[21]. fig. 6. effect of poly (iso-octyl acrylate) copolymer on the pour point of stocks 40 & 60 4conclusion the two acrylates derived polymers have shown a good vi, and pour point improvement levels. they were proved to be more efficient than the commercial olefin copolymer. the branched acrylate derived copolymer was better than the un-branched one. the lower viscosity iraqi base oil is more affected by the presence of additives. the optimum weight fraction of poly (iso-octyl acrylate) additive is 10 wt. % for both base stock 40, and base stock 60, where the vi is 200, and 150 respectively, while the pour point is -24 and -18 respectively. for poly (n-decyl acrylate) additive, the optimum weight fraction is also 10 wt. % for base stock 40, and base stock 60, where the vi is 186, and 142 respectively, while the pour point is -24, and -15 respectively. for hitec 5748 additive, the optimum weight fraction is 6 wt. % for base stock 40, and 8 wt. % for base stock 60, where, the vi is 177 and 129 respectively while the pour point is -18 and -12 respectively. economically, the base stock 40 is better than base stock 60 because higher vis and lower pour points can be earned with fewer amounts of additive. acknowledgement we express our great appreciation for al-daura refineries, and the department of chemical engineering at the university of nahrain, for their efforts in facilitating the task of research. references [1] ludema, k.c. “friction, wear, lubrication, a textbook in tribology”, crc press l.l.c., 1996. [2] rob heverly “lubricant additives”, r. t. vanderbilt, company, inc., houston, 2012. [3] stevens, c., and roland verhé “renewable bioresources: scope and modification for non-food applications”, john wiley & sonce, ltd, chichester, 2004. [4] mortier, r. m., fox, m. f., and orszulik, s. t. “chemistry and technology of lubricants” springer, dordrecht, 3rd edition, 2010. [5] pranab, g., das tapan and das moumita, 2011, “evaluation of poly (acrylates) and their copolymer as viscosity modifiers”, res. j. chem. sci., volume 1, issue 3, pp.18-25. [6] abdul-halim a. mohammed, and noor s. akram, 2010, “the effect of operating conditions of urea dewaxing on the pour point of light lubricating oil”, iraqi journal of chemical and petroleum engineering, vol.11 no.1, pp 59-63. [7] abdul-halim a.-k. mohammed, hussain k. hussain, and rafal j. sadiq, 2007, “the effect of solvent extraction of light lubricating oil on viscosity index and chemical composition”, iraqi journal of chemical and petroleum engineering, vol.8, no.4, pp.1-12. [8] wang, y., and eli, w., 2010, “synthesis of biodegradable high-alkali magnesium oleate detergent”, ind. eng. chem. res., volume 49, pp.2589– 2592. [9] ghiyath a. r. rassoul and laith s. mahmmoud, 2010, “treating the used automobiles oils using solvents”, iraqi journal of chemical and petroleum engineering, vol. 11, no.3, pp. 9-14. [10] nehal s. ahmed, amal m. nassar, 2009, “lubricating oil additives based on poly alkyl polyamines”, international journal of polymeric materials and polymeric biomaterials, volume 58, issue 3, pp. 170-198. [11] rios, m.a., s.n. santiago, a.a. lopes, and s.e. mazetto, 2010, “antioxidative activity of 5-npentadecyl-2-tert-butylphenol stabilizers in mineral lubricant oil”, energy & fuels, volume 24, issue 5, pp.3285–3291. [12] pospíšil, j., 1995, “polysoaps, stabilizers, nitrogen-15 nmr, advances in polymer science”, volume 124, issue 6, pp.87-189. [13] bloch, h. p. “practical lubrication for industrial facilities”, the fairmont press, inc., lilburn, 2000. [14] furniss, b. s., a. j. hannaford, p. w. g. smitch, and a. r. tatchell, “vogel's textbook of practical organic chemistry”, 5th edition, new york, 1989. [15] margareth judith souza de carvalho, peter rudolf seidl, carlos rodrigues pereira belchior, josé ricardo sodré, 2010, “lubricant viscosity and viscosity improver additive effects on diesel fuel economy”, tribology international, volume 43, issue 12, pages 2298-2302. [16] salah a. mohamad, nehal s. ahmed, saeed m. hassanein, ahmed m. rashad, 2012, “investigation of polyacrylates copolymers as lube oil viscosity index improvers”, journal of petroleum science and engineering,volume 100, pages 173-177. https://www.taylorfrancis.com/books/9781439821893. https://www.taylorfrancis.com/books/9781439821893. https://docplayer.net/27824518-lubricant-additives-stle-houston-february-8-rob-heverly-r-t-vanderbilt-co.html. https://docplayer.net/27824518-lubricant-additives-stle-houston-february-8-rob-heverly-r-t-vanderbilt-co.html. https://www.wiley.com/en-us/renewable+bioresources%3a+scope+and+modification+for+non+food+applications-p-9780470854464. https://www.wiley.com/en-us/renewable+bioresources%3a+scope+and+modification+for+non+food+applications-p-9780470854464. https://www.wiley.com/en-us/renewable+bioresources%3a+scope+and+modification+for+non+food+applications-p-9780470854464. https://www.wiley.com/en-us/renewable+bioresources%3a+scope+and+modification+for+non+food+applications-p-9780470854464. https://www.springer.com/gp/book/9781402086618. https://www.springer.com/gp/book/9781402086618. https://www.springer.com/gp/book/9781402086618. http://www.isca.in/rjcs/archives/v1/i3/03.php. http://www.isca.in/rjcs/archives/v1/i3/03.php. http://www.isca.in/rjcs/archives/v1/i3/03.php. http://www.isca.in/rjcs/archives/v1/i3/03.php. http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/370 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/370 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/370 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/370 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/370 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/490 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/490 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/490 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/490 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/490 https://pubs.acs.org/doi/abs/10.1021/ie901569g https://pubs.acs.org/doi/abs/10.1021/ie901569g https://pubs.acs.org/doi/abs/10.1021/ie901569g https://pubs.acs.org/doi/abs/10.1021/ie901569g http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/379 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/379 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/379 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/379 https://www.tandfonline.com/doi/abs/10.1080/00914030701551071. https://www.tandfonline.com/doi/abs/10.1080/00914030701551071. https://www.tandfonline.com/doi/abs/10.1080/00914030701551071. https://www.tandfonline.com/doi/abs/10.1080/00914030701551071. https://www.tandfonline.com/doi/abs/10.1080/00914030701551071. https://pubs.acs.org/doi/abs/10.1021/ef100262j https://pubs.acs.org/doi/abs/10.1021/ef100262j https://pubs.acs.org/doi/abs/10.1021/ef100262j https://pubs.acs.org/doi/abs/10.1021/ef100262j https://pubs.acs.org/doi/abs/10.1021/ef100262j https://www.amazon.co.uk/polysoaps-stabilizers-nitrogen-15-advances-polymer/dp/354058983x. https://www.amazon.co.uk/polysoaps-stabilizers-nitrogen-15-advances-polymer/dp/354058983x. https://www.amazon.co.uk/polysoaps-stabilizers-nitrogen-15-advances-polymer/dp/354058983x. https://content.taylorfrancis.com/books/download?dac=c2006-0-01831-9&isbn=9781439824665&format=googlepreviewpdf https://content.taylorfrancis.com/books/download?dac=c2006-0-01831-9&isbn=9781439824665&format=googlepreviewpdf https://www.sciencedirect.com/science/article/pii/s0301679x10001854. https://www.sciencedirect.com/science/article/pii/s0301679x10001854. https://www.sciencedirect.com/science/article/pii/s0301679x10001854. https://www.sciencedirect.com/science/article/pii/s0301679x10001854. https://www.sciencedirect.com/science/article/pii/s0301679x10001854. https://www.sciencedirect.com/science/article/abs/pii/s092041051200157x. https://www.sciencedirect.com/science/article/abs/pii/s092041051200157x. https://www.sciencedirect.com/science/article/abs/pii/s092041051200157x. https://www.sciencedirect.com/science/article/abs/pii/s092041051200157x. https://www.sciencedirect.com/science/article/abs/pii/s092041051200157x. r. f. abdul-saheb and m. a. mohammed / iraqi journal of chemical and petroleum engineering 20,3 (2019) 7 21 02 [17] joshua w. robinson, yan zhou, jun qu, j. timothy bays, lelia cosimbescu, 2016, “highly branched polyethylenes as lubricant viscosity and friction modifiers”, reactive and functional polymers,volume 109, pages 52-55. [18] sheida shahnazar, samira bagheri, sharifah bee abd hamid 2016, “enhancing lubricant properties by nanoparticle additives”, international journal of hydrogen energy, volume 41, issue 4, pages 3153-3170. [19] c. d. neveu, r. sondjaja, t. stöhr k. schimossek, n. j. iroff, “lubricant and fuel additives based on polyalkylmethacrylates”, reference module in materials science and materials engineering, 2016. [20] mohammad hemmat esfe, ali akbar abbasian arani, 2018, “an experimental determination and accurate prediction of dynamic viscosity of mwcnt(%40)-sio2(%60)/5w50 nano-lubricant”, journal of molecular liquids, volume 259, pages 227237. [21] obasi, a.u, udeagbara, s.g, anusiobi, o.j., 2014, “effect of additives on the performance of engine oil”, international journal of engineering and technology research, volume 2, issue 9, pp. 1 -11, [22] rudnick, l.r. (editor) “lubricant additives: chemistry and applications” 2nd edition. crc press, taylor & francis group, new york, 2009. [23] nehal s. ahmed and amal m. nassar, 2011, “lubricating oil additives: a chapter in tribology lubricants and lubrication”, egyptian petroleum research institute, egypt, p.p.250-268. [24] kavindra singh, amit suhane, 2016, “effect of additive addition in base oil of a lubricant – a review”, international research journal of engineering and technology, india, volume 3, issue 4, p.p.2636-2639. [25] jukić, a., marko rogošić and zvonimir janović, 2007, “optimization of alkyl methacrylate terpolymer properties as lubricating oil rheology modifier”, ind. eng. chem. res., volume 46, issue 10, pp.3321–3327. [26] nehal s. ahmed, amal m. nassar, 2009, “lubricating oil additives based on poly alkyl polyamines”, international journal of polymeric materials and polymeric biomaterials, volume 58, issue 3, pp. 170-198. [27] pranab, g., das tapan and das moumita, 2011, “evaluation of poly (acrylates) and their copolymer as viscosity modifiers”, res. j. chem. sci., volume 1, issue 3, pp.18-25. [28] nehal s. ahmed, amal m. nassar, r.m. nasser, a.f. khattab, and a.a. abdel-azim, 2008, “synthesis and evaluation of some polymeric compounds as pour point depressants and viscosity index improvers for lube oil”, journal of petroleum science and technology, volume 26, issue 12, pp. 1390-1402. دراسة مقارنة لتأثير أنواع مختمفة من البوليمرات عمى مؤشر المزوجة ونقطة االنسكاب لزيوت االساس العراقية عبدالرزاق محمدرسل فيصل عبدالصاحب و مهند جامعة النهرين الخالصة في هذا البحث، تمت دراسة آثار مزج البوليمرات المشتقه من االكريميت وتحديدا ) بولي ديكين االكريميت غير المتفرع و بولي اوكتيل االكريميت المتفرع( عمى معامل المزوجة ونقطة االنسكاب لزيوت االساس العراقيه . ان مستوى التحسن في كل من معامل المزوجة . تم استخدام التموين كمذيب و حامل لكال البوليمرين04و 04 و نقطة االنسكاب الناتج عن مزج الزيوت مع البوليمرات المشتقه من األكريميت تم تقييمه استنادا عمى مقارنته مع القيم المستحصل عميها عند مزج الزيوت مع مضاف محسن لزوجة ونقطة االنسكاب تجاري. ان المضاف ن قبل مصفى الدورة يتكون من اولوفين كوبوليمر و حامل غير معروفين. كل التجاري هو مضاف معتمد م ٪ ( مع كل نوع من انواع زيوت األساس. وكانت 0،0،1،،،24المضافات الثالثه تم خمطها بنسب وزنيه ) نتيجة الدراسة أن التحسن في مؤشر المزوجة ونقطة االنسكاب لزيوت األساس العراقية يكون ذو قيمة اعمى عند استخدام مشتقات األكريميت عند مقارنتها بمستوى التحسن عند استخدام المضاف التجاري انكهمات اندانة: زيوت, معامم انهسوجة, نقطة انصب, بول اكريهيث https://www.sciencedirect.com/science/article/abs/pii/s1381514816301900. https://www.sciencedirect.com/science/article/abs/pii/s1381514816301900. https://www.sciencedirect.com/science/article/abs/pii/s1381514816301900. https://www.sciencedirect.com/science/article/abs/pii/s1381514816301900. https://www.sciencedirect.com/science/article/abs/pii/s1381514816301900. https://www.sciencedirect.com/science/article/pii/s0360319915300896. https://www.sciencedirect.com/science/article/pii/s0360319915300896. https://www.sciencedirect.com/science/article/pii/s0360319915300896. https://www.sciencedirect.com/science/article/pii/s0360319915300896. https://www.sciencedirect.com/science/article/pii/b9780128035818015447. https://www.sciencedirect.com/science/article/pii/b9780128035818015447. https://www.sciencedirect.com/science/article/pii/b9780128035818015447. https://www.sciencedirect.com/science/article/pii/b9780128035818015447. https://www.sciencedirect.com/science/article/pii/s0167732217344549. https://www.sciencedirect.com/science/article/pii/s0167732217344549. https://www.sciencedirect.com/science/article/pii/s0167732217344549. https://www.sciencedirect.com/science/article/pii/s0167732217344549. https://www.sciencedirect.com/science/article/pii/s0167732217344549. https://www.sciencedirect.com/science/article/pii/s0167732217344549. https://www.intechopen.com/books/tribology-lubricants-and-lubrication/lubricating-oil-additives. https://www.intechopen.com/books/tribology-lubricants-and-lubrication/lubricating-oil-additives. https://www.intechopen.com/books/tribology-lubricants-and-lubrication/lubricating-oil-additives. https://www.intechopen.com/books/tribology-lubricants-and-lubrication/lubricating-oil-additives. https://www.irjet.net/archives/v3/i4/irjet-v3i4523.pdf. https://www.irjet.net/archives/v3/i4/irjet-v3i4523.pdf. https://www.irjet.net/archives/v3/i4/irjet-v3i4523.pdf. https://www.irjet.net/archives/v3/i4/irjet-v3i4523.pdf. https://pubs.acs.org/doi/abs/10.1021/ie060890c https://pubs.acs.org/doi/abs/10.1021/ie060890c https://pubs.acs.org/doi/abs/10.1021/ie060890c https://pubs.acs.org/doi/abs/10.1021/ie060890c https://www.tandfonline.com/doi/abs/10.1080/00914030701551071. https://www.tandfonline.com/doi/abs/10.1080/00914030701551071. https://www.tandfonline.com/doi/abs/10.1080/00914030701551071. https://www.tandfonline.com/doi/abs/10.1080/00914030701551071. https://www.tandfonline.com/doi/abs/10.1080/00914030701551071. http://www.isca.in/rjcs/archives/v1/i3/03.php. http://www.isca.in/rjcs/archives/v1/i3/03.php. http://www.isca.in/rjcs/archives/v1/i3/03.php. http://www.isca.in/rjcs/archives/v1/i3/03.php. https://www.tandfonline.com/doi/abs/10.1080/10916460701272195?src=recsys&journalcode=lpet20. https://www.tandfonline.com/doi/abs/10.1080/10916460701272195?src=recsys&journalcode=lpet20. https://www.tandfonline.com/doi/abs/10.1080/10916460701272195?src=recsys&journalcode=lpet20. https://www.tandfonline.com/doi/abs/10.1080/10916460701272195?src=recsys&journalcode=lpet20. https://www.tandfonline.com/doi/abs/10.1080/10916460701272195?src=recsys&journalcode=lpet20. https://www.tandfonline.com/doi/abs/10.1080/10916460701272195?src=recsys&journalcode=lpet20. 35 ijcpe vol.10 no.1 (march 2009) iraqi journal of chemical and petroleum engineering vol.10 no.1 (march2009) 35-41 issn: 1997-4884 purification of zinc oxide using direct thermal process by petroleum coke salam k. al-dawery * , zuhair a-a. khammas ** and thaer adnan abdulla * chemical engineering department college of engineering university of baghdad – iraq ** chemistry departmentcollege of scienceuniversity of dayla-iraq abstract the present investigation is concerned for the purification of impure zinc oxide (80-85 wt %) by using petroleum coke (carbon content is 76 wt %) as reducing agent for the impure zinc oxide to provide pure zinc vapor, which will be oxidized later by air to the pure zinc oxide. the operating conditions of the reaction were studied in detail which are, reaction time within the range (10 to 30 min), reaction temperature (900 to 1100 oc), air flow rate (0.2 to 1 l/min) and weight percentage of the reducing agent (petroleum coke) in the feed (14 to 30 wt %). the best operating conditions were (30 min) for the reaction time, (1100 oc) for the reaction temperature, (1 l/min) for the air flow rate, and (30 wt %) of reducing material (petroleum coke) in the feed. under the above conditions, conversion of zinc oxide was (68.12 %) and the purity of the produced zinc oxide was (97.85 %) by using petroleum coke as reducing material. introduction zinc oxide (zno) is commercially the most important chemical compound of zinc. it is a fluffy, white powder, hexagonal crystal with exceptional and unique properties. having a specific gravity (sp.gr.) of (5.68) and molecular weight (m) of (81.38 gm/gmol.), it sublimes at (1800 oc), is insoluble in water, and soluble in strong alkali solutions and acids. these distinct properties are utilized in many types of applications such as agriculture, ceramics, chemicals, paints, photocopying and rubber industries, the largest consumer of (zno) is the rubber industry (1). the zinc oxide is produced by two thermal methods, in addition to wet (chemical) method. the two thermal methods are known as the direct and indirect, depending upon whether the raw material was zinc oxide in the form of calcined ore or drosses, or metallic zinc. as usual in the zinc industry a number of different types of furnaces have been developed to exploit each of the thermal methods (2). the indirect (french) process is historically the older, but today is used to produce only about one-half as much zinc oxide as the direct (american) process. french process zinc oxide is purer and finer than american process zinc oxide but french process is more costly than american process. the chemical (wet) process is much costly compared with the thermal processes, so it is not used largely in the industrial field (3). very few studies have been made on the reduction of zinc oxide or the oxidation of zinc vapor as shown below. in 1917, bodenstein (2,4,5) showed that the reduction of zinc oxide by carbon as follows: zno(s) + c(s)  zn(g) + co(g) (1) proceeded by two successive gas-solid reactions which were readily reversible: university of baghdad college of engineering iraqi journal of chemical and petroleum engineering purification of zinc oxide using direct thermal process by petroleum coke 36 ijcpe vol.10 no.1 (march 2009) zno(s) + co (g)  zn (g) + co2 (g) [actual reduction step] (2) c(s) + co2 (g)  2co (g) [regeneration of co] (3) the first thorough thermodynamic study of this reduction was carried out by c.g. maier (6) and his colleagues at the u.s. bureau of mines. they specified the temperature at which continuous reduction of zinc oxide could be begin, and the proportions of zinc vapor, carbon monoxide and carbon dioxide which would exist at all temperatures of interest in practical. the reduction of (zno) by carbon cannot take place except above the boiling point of zinc (907 ºc) so that the zinc product of the reduction process is always in the vapor phase. the reaction (3) is the slower than the reaction (2) below about (1100 ºc) and hence controls the rate of reduction in most commercial processes. above (1100 ºc), the rates of diffusion and heat transfer predominate as rate-controlling factors. chen (7) studied the effect of the gas flow rate, grain size, molar ratio of (c/zno), solid sample height, initial bulk density and reaction temperature on the reaction rate of the carbothermic reduction of pure zinc oxide with carbon powder under a nitrogen atmosphere (at 1 atm). solid reactants in the predetermined proportions were then mixed in a v blender and then transferred to a cylindrical quartz crucible and nitrogen was flowed over the solid sample and the conversion of zinc oxide and carbon as well as the yield of zinc were determined. the weights of solid samples were in the range of (5*10-4 to 1.5 *10-3 kg). the operating variables studied are shown below: 1. (c/zno) molar ratio (1.0, 1.5, 2.0, 2.5) 2. carbon grain size (5, 39, 414), (*107 m). 3. zinc oxide grain size (5, 39, 414), (*107 m). 4. solid sample height (0.005, 0.01.0.015, 0.02), (m). 5. initial bulk density () (216.7, 336.5, 454.3, 570.4), (kg/m3). 6. reaction temperature (1073, 1173, 1273, 1373, 1423), (k). 7. nitrogen gas flow rate (0.167, 0.833, 1.25, 1.67)(*105 m3/s). chen found that the conversion of zinc oxide could be increased by increasing the molar ratio of (c/zno), height of solid sample, density of solid sample or reaction temperature and also found that the conversion of zinc oxide could be increased by reducing the grain size of zinc oxide and carbon or the nitrogen gas flow rate. both clarke and fray (8,9), and stott and fray (10) studied the oxidation of zinc vapor according to the reverse of reaction (2). the flow technique and carbon monoxide, argon or nitrogen, with or without additional carbon dioxide mixtures were used with a temperature range (600-900 °c) and experimental apparatus consisted of a flow reactor and multi temperature zones, resistance furnace in these investigations. under the reaction conditions investigated two distinct reaction regimes were observed; in both cases the reaction rate was found to be controlled by surface chemical reactions as opposed to gas phase diffusion. below (800 °c), the reaction rate at any given temperature was found to be controlled by prevailing excess zinc partial pressure (the surface adsorption of zinc). for this regime a massive oxide deposit with a grain size in the range (5-20 μm) and typical reaction rates of (1-3 * 10-7 mol cm-2 s–1) were observed. in contrast, above (800 ºc) and the carbon monoxide partial pressure in excess of (0.2 atm), the reaction rate was found to be strongly dependent on the prevailing carbon monoxide concentration, with the carbon monoxide appearing to retard the rate. for this regime the main type of growth was found to have a much finer grain size, in the range of (1-2 μm), with typical deposition rates of (0.5-1.5 * 10-8 mol cm-2 s–1). these investigations were also extended by clarke and fray (11) to the study of the oxidation of zinc vapor in the mixed gas system (co/co2/ h2/h2o/ar). the same experimental procedure was adopted as in the simpler reaction system. over the temperature range investigated (600-900 °c), the reaction rate was similar to that of the massive oxide of (co/co2/ar) system, and a finer grained deposit was not observed. the reaction rate was again found to be linearly dependent on the excess zinc partial pressure, but a plot of reaction rate versus the prevailing zinc partial pressure, did not in this case produce a single straight line. instead, it consisted of two distinct straight-line portions. the two slopes were found to be dependent on the gas composition, and in particular on the relative abundances of the two constituent reaction systems. for these gas mixtures zinc oxidation will not be the sole reaction occurring, since the interaction of the other constituent gases salam k. al-dawery, dr. zuhair a-a. khammas and mr. thaer adnan abdulla 37 ijcpe vol.10 no.1 (march 2009) fig.1 schematic diagram of the experiment laboratory unit t. according to the “gas shift” reaction will also take place: h2 + co2  co + h2o (4) cox and fray (12) studied the zinc vapor reoxidation in the shaft of a zinc-lead imperial smelting process in the mixed gas system (co/co2/h2/h2o) by passing the gases through a heated quartz reactor containing zinc oxide pellets. the reverse of reaction (2) is the basic re-oxidation reaction. at temperature less than 750 ºc (< 750 ºc), a distinct correlation was found between the deposition rate, excess zinc partial pressure and zinc oxide morphology. furthermore, the deposition rate at temperatures more than 850 ºc (> 850 ºc) was significantly greater than that at (< 750 ºc), the greater thermodynamic driving force losing out to the reduced temperature kinetic effect. two distinct types of crystals were produced for the two temperature ranges, indicating two different mechanisms of formation. osborne, rankin, mccarthy, and swinbourne (13) studied the oxidation of zinc vapor in the (zn-coco2-n2) system for zinc partial pressure of (0.01 to 0.09 atm), carbon monoxide partial pressures up to (0.5 atm), and carbon dioxide partial pressures up to (0.6 atm) at (730 to 900 ºc). the experimental apparatus consisted of a flow reactor and a multi temperature zone furnace. the rate of oxidation of zinc was found to be a function of temperature and of the partial pressures of zinc, carbon monoxide, and carbon dioxide. it was autocatalytic with respect to carbon monoxide and independent of the total mass of zinc oxide deposited. the reactions occurring in parallel for this mechanism are the reverse of reaction (2.2) and the following reaction: zn(g) + co2(g) + co(g)  zno(s) + 2co(s) (5) the aim of this study is to develop a laboratory system for the purification of an impure zinc oxide produced by-product (80-85%) in copper production process from brass scrap in al-shaheed company, and obtain the best conditions (reaction time, reaction temperature, air flow rate and weight percentage of reducing agent in feed) for the purification process of an impure zinc oxide with high yield to achieve the required technical specifications of this oxide for the industrial purposes. experimental work feed briquetting generally, briquetting is a process for compressing fine materials into small blocks, or agglomerates, of sufficient mechanical strength to resist reasonable handling and weathering without deterioration. the main purpose of briquetting in the zinc oxide industry is to form strong briquettes composed of a homogenous mixture of the impure zinc oxide and the petroleum coke which will not impede the flow of gases or seriously disintegrate during the reducing operation. the briquetting process for preparing samples of the impure zinc oxide is shown in the following five principal steps: a) drying and grinding of the impure zinc oxide, (b) drying and grinding of the petroleum coke, (c) mixing and plasticizing the raw materials (impure zinc oxide and petroleum coke), (d) pressing of plastic mixture in the briquetting machine, and (e) drying of the material briquettes. the briquettes had cylindrical shape with dimensions (3mm diameter and 5mm length). purification of zinc oxide using direct thermal process by petroleum coke 38 ijcpe vol.10 no.1 (march 2009) laboratory experiment unit figure (1) shows a schematic diagram of the laboratory experiment unit, which is employed for the purification of an impure zinc oxide by using the petroleum coke as reducing agent. raw materials the full description of the materials, which were used in this work, is shown below: a. laboratory materials 1. alumina (al2o3) a high-purity alumina (99.999 %) was purchased from (bdh limited poole-england), with bulk density of (660 kg/m3), and used as a binder in feed briquetting. 2. hydrochloric acid (hcl) a concentrated hydrochloric acid (36 wt %) was purchased from (hopkin and williams companyengland), and was used as a cleaning solvent for the reactor quartz tube after each experiment. b. raw materials 1. impure zinc oxide this material brought from al-shaheed general company as a by-product from the copper production process. it contains (80-85 wt %) of zinc oxide and (15-20 wt %) of impurities. 2. petroleum coke it was obtained from the quiyarah refinery (iraq) and contained (76 wt %) carbon with high sulfur content about (7.5 %). it was used as reducing agent for the impure zinc oxide in this research. five grams of feed briquettes are bedded evenly (in the same level (10 mm)) on the stainless steel boat. the sample is then pushed inside the isothermal zone of the (60 mm diameter quartz tube) by using stainless steel rod and boat. the electrical tubular furnace switching on and maintaining the furnace temperature at desired temperature (i.e. 900-1100 ºc) by using the automatic temperature controller. during this period (before the reaching to the desired temperature), the nitrogen gas is then allowed to flow at constant flow rate (0.1 l/min) to the (60 mm diameter quartz tube) through the rotameter (2) in order to ensure that only reduction reaction had occurred during this period without any oxidation reaction for zinc vapor. stopping the nitrogen gas flow rate and switching on the vacuum pump to allow the air to flow at flow rate (0.2-1 l/min) to the (12.7 mm diameter quartz tube) through the rotameter (1) after the reaching to the desired temperature. when the inlet air is flowed through the tubular furnace, the oxidation reaction is started and zinc oxide fume is produced with reaction gases of carbon monoxide (co), carbon dioxide (co2) and air during this reaction. this product was cooled in the countercurrent condenser by water. the decreasing of temperature in the condenser increased the oxidation reaction because the oxidation reaction is exothermic. so, the growth of zinc oxide crystals is occurred on the surface of condenser. part of the produced zinc oxide was deposited on the surface of the inner pipe of the condenser and the other part was collected by the pyrex and plastic traps before the reaction gases reached the vacuum pump. produced zinc oxide analysis the purity of produced zinc oxide was determined by using the titration method. the solutions of (0.015 m) edta and (0.015 m) zinc chloride were prepared. also, an (eriochrome black t) indicator solution was prepared by adding (0.1 gm) of this indicator in (25 ml) methanol. the weighted sample (0.2-0.25 gm) of the produced zinc oxide sample was dissolved in (250 ml) of concentrated hydrochloric acid (conc.hcl) to prepare the sample solution. after that, (25 ml) from the prepared sample solution was taken and put in the volumetric flask, then adding (50 ml) of the prepared edta and (10 ml) of concentrated ammonia solution to the flask in order to adjust the (ph) in the range (10-11). also, drops of the (eriochrome black t) solution was added to the flask and finally, a titration with the prepared zinc chloride solution to a color change from blue to purple and volume of the titrated zinc chloride solution was (u). we repeated this titration without using the sample solution (blank) and the volume of titrated zinc chloride solution was (b). the purity of the produced zinc oxide could be calculated by using the following relation: (6) 100* m 1.245*m*u)(b wt%zno,   salam k. al-dawery, dr. zuhair a-a. khammas and mr. thaer adnan abdulla 39 ijcpe vol.10 no.1 (march 2009) fig. (2): effect of reaction time on the conversion of zinc oxide at various temperatures using petroleum coke at 1 l/min and 30 wt% of petroleum coke in feed. fig. (3): effect of reaction time on the conversion of zinc oxide at various air flow rates using petroleum coke at 1100 o c and 30 wt % of petroleum coke in feed. where: b = titrated zinc chloride solution volume without using sample solution u = titrated zinc chloride solution volume with usingsample solution. m = 1.1(correction factor). m = sample weight in (gm)= 0.2-0.25 gm. 1.245 = ratio of molecular weights of zinc oxide to zinc. results and discussion figure (2) shows the interaction effect of reaction time and reaction temperature on the conversion of zinc oxide. the conversion of zinc oxide had endured increasing function with respect to both reaction time and reaction temperature. this figure shows that the two variables (i.e., the reaction time and temperature) had concurred their influences, which resulted in an increase in conversion of zinc oxide with reaction time and temperature. this effect may be attributed to the reaction of zinc oxide reduction is endothermic. figure (3) shows the interaction effect between reaction time and air flow rate. in this figure, had endured increasing function with respect to both reaction time and air flow rate. this effect may be attributed to increasing the carbon dioxide gas concentration due to increasing the air flow rate. figure (4) shows the interaction effect between reaction time and weight percentage of petroleum coke in the feed .this figure shows that the conversion of zinc oxide had endured increasing function with respect to both reaction time and weight percentage of petroleum coke in the feed. this effect may be attributed to increasing the carbon monoxide gas concentration due to increasing the weight percentage of carbonaceous materials in the feed. figure (5) shows the interaction effect between reaction temperature and air flow rate. this figure shows that the conversion of zinc oxide had endured increasing function with respect to both reaction temperature and air flow rate. this effect may be attributed to the endothermic reaction of zinc oxide reduction and also to increasing the carbon dioxide gas concentration due to increasing the air flow rate. figure (6) represents the interaction between reaction temperature and weight percentage of petroleum coke. this figure shows that the conversion of zinc oxide had endured increasing function with respect to both reaction temperature and weight percentage of petroleum coke. this effect may be attributed to the endothermic reaction of zinc oxide reduction and also more carbon monoxide gas is provided due to increasing weight percentage of petroleum coke in the feed. eventually, figure (7) shows the interaction dependence between air flow rate and weight percentage of petroleum coke. this figure shows that that the conversion of zinc oxide had endured increasing function with respect to both air flow rate and weight percentage of petroleum coke. this effect may be attributed to increasing the concentrations of carbon monoxide and carbon dioxide gases due to increasing weight percentage of petroleum coke and air flow rate respectively. purification of zinc oxide using direct thermal process by petroleum coke 40 ijcpe vol.10 no.1 (march 2009) fig. (4): effect of reaction time on the conversion of zinc oxide at various weight percentages of petroleum coke in the feed at 1100 o c and 1 l/min. fig. (5): effect of air flow rate on the conversion of zinc oxide at various temperatures using petroleum coke at 30 min and 30 wt % of petroleum coke in feed. fig. (6): effect of the weight percentage of petroleum coke in the feed on the conversion of zinc oxide at various temperatures at 30 min and 1 l/min. fig. (7): effect of air flow rate on the conversion of zinc oxide at various weight percentage of petroleum coke in the feed at 30 min and 1100 o c. salam k. al-dawery, dr. zuhair a-a. khammas and mr. thaer adnan abdulla 41 ijcpe vol.10 no.1 (march 2009) conclusions 1the best conditions for laboratory unit of zinc oxide purification by using petroleum coke as reducing agent were as follows: i) reaction time: 30 min (10-30 min). ii) reaction temperature:1100 o c(900-1100 o c). iii) air flow rate: 1 l / min (0.2-1 l / min). iv) weight percentage of petroleum coke: 30 wt % in the feed (14 30 wt %). 2 as the above mentioned parameters attempted rising in this study, tend to increase the conversion (%) of zinc oxide. nomenclature sp. gr. specific gravity (-) m molecular weight (gm/g mol) x1 reaction time (min) x2 reaction temperature ( o c) x3 air flow rate (l/min) x4 weight percentage of petroleum coke in feed (wt %) n number of experiments (-)  axial distance from the center point (-) q number of variables (-) y predicted value of the conversion of zinc oxide (-) y observed value of the conversion of zinc oxide (-) t reaction time (min) t reaction temperature ( o c) f air flow rate (l/min) c2 weight percentage of petroleum coke in feed (wt %) references 1. abdullatif, a.r., “ preparation and characterization of zinc oxide powder for ceramic industry ”, ph.d. thesis (technology university, iraq), 1996. 2. morgan, s.w.k., “ zinc and its alloy and compounds ”, ellis horwood ltd., england, p.(218-223,26,56-59), 1985. 3. shreve, r.n. , “ chemical process industries ”, mcgraw-hill, chem. eng., chem. eng. series, p.(434436),1967. 4. gilchrist, j.d., “ extraction metallurgy”, pergamon press. ltd., england, 2nd ed., p.(390-393), 1980. 5. bray, j.l., “ non-ferrous production metallurgy”, pergamon press.ltd. england, 2nd ed., p.(490-493), 1953. 6. mair, c.g., j.am.chem.soc., vol. 48, p.(364-374), 1926. 7. his-kuei chen, scandinavian j. of metallurgy, vol.30, p.(292-296),2001. 8. clarke, j.a., chemistry and industry, jan. 6, p.(5-10), 1979. 9. clark, j.a., and fray, d.j., i.chem.symp., series no. 43, 1975 (see ref. 38). 11. clarke, j.a., “ oxidation kinetics of zinc vapor” thesis (cambridge university), 1976 (see ref. 38). 12. cox, a. and fray, d.j.,“ mineral processing and extractive metallurgy”, section c, vol. 109, p.(97-104), 2001 (abstract). 13. osborne, j.m., rankin, w.j., mccarthy, d.j. and swinbourne,d.r.,metallurgical and materials transactions, section b, vol. 32, no. 2, p.(37-45), 2001 (abstract). 14. liddel, d.m. , “ handbook of nonferrous metallurgy ”, vol. 1, 2nd ed., p.(409-428), new york, mcgrawhill book company, inc. ,1945. 15. welcher, f.j., ed. , “ standard methods of chemical analysis ”, d.van nostrand co., inc., princeton, n.j., vol. 2b, 6th ed., p. 1344,1963. 16. anderson, s.l., “ chemical engineering progress ”, vol. 55, p. 10,1959. 17. box, g.e., and hunter, j.c., “ ann. math ”, vol. 3, p. 195, 1957. 18. davies, o.l., “ design and analysis of industrial experiments ”, 1971. 19. feki, m., and vaillant, m., canadian j. of chem. eng., vol. 65, p. 132, 1987. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.20 no.2 (june 2019) 23 – 32 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: marah waleed khalid , email: mw.alsharod@gmail.com, name: sami d. salman, email: sami.albayati@gmail.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. adsorption of chromium ions on activated carbon produced from cow bones marah waleed khalid and sami d. salman alkhwarizmi college of engineering, university of baghdad, baghdad, iraq abstract due to the broad range uses of chromium for industrial purposes, besides its carcinogenic effect, an efficient, cost effective removal method should be obtained. in this study, cow bones as a cheap raw material were utilized to produce active carbon (cbac) by physiochemical activation, which was characterized using: sem to investigate surface morphology and bet to estimate the specific surface area. the best surface area of cbac was 595.9 m 2 /gm which was prepared at 600 ᵒ c activation temperature and impregnation ratio of 1:1.5. cbac was used in aqueous chromium ions adsorption. the investigated factors and their ranges are: initial concentration (10-50 mg/l), adsorption time (30-300 min), temperature (20-50 ᵒ c) and solution ph (2-11). isotherm of adsorption and its kinetics were studied. the adsorption process was modeled statistically and was represented by an empirical model. equilibrium data were fitted to the langmuir and freundlich isotherm models and the data best represented by freundlich isotherm. pseudofirst order and pseudosecond order kinetic equations were utilized to study adsorption kinetics, where chromium adsorption on cbac fitted pseudosecond order fitted the data more adequately. the best removal efficiency was found to be 94.32%. keywords: adsorption, activated carbon, cow bones, chromium, physiochemical activation. received on 06/02/2019, accepted on 23/03/2019, published on 30/06/1029 https://doi.org/10.31699/ijcpe.2019.2.4 1introduction due to the wide range and the exaggerated uses of organic solvents, oxidizing agents, phenols and heavy metals in industry, they were accumulated in the environment, which led some ecosystems to deteriorate. heavy metals category is one of the most harmful pollutants of surface and ground waters. industrial effluents are the primary source. because almost all of the heavy metals could not be degraded to harmless components ‎[1]; therefore reduction of heavy metals concentrations before discharging them into rivers had become a necessity. otherwise, they could be harmful to health and/or reduce drinking water quality ‎[2]. according to the world health organization (who, 1984) and international program on chemical safety (ipcs, 1988), the most toxic metals are aluminum, zinc, mercury, arsenic, chromium, nickel, copper, cadmium and lead. the drinking water guideline value recommended by the world health organization (who) and iraqi standard regulation is 0.01 and 0.015 mg pb/l. chromium is found in freshwaters due to its extensive use in petrochemical, electronics, tanneries, electroplating industries, mining operations, as well as in textile mill products ‎[3]. chromium is carcinogenic ‎[4] and causes severe damage to human organs: e.g., to the kidneys, the brain, reproductive system, the liver, and the nervous system ‎[5]. as a result of the toxicity of this element and its compounds, removal has become an urgent priority. there are various available means to reduce heavy metals levels from water including ion exchange ‎[6], ‎[7], membrane filtration ‎[8], ‎[9], chemical precipitation ‎[10], ‎[11] and electrocoagulation ‎[12], ‎[13], but these methods generally require high cost and produce more lethal products ‎[14]. adsorption on solid materials is one of the best existing methods for the refinement of water and the regulation of atmospheric and aquatic pollution, with active carbon being the most used adsorbent in the industry ‎[6]. in the last years, global consumption of active carbon has increased by an average annual increase of 5.5% and it is anticipated to continue to do so at a higher rate in next years (8.1% in 2018)‎[15]. activated carbon has been established as effective adsorbents for the removal of a wide variety of pollutants dissolved in aqueous media, or from the gaseous environment due to its exceptionally high surface areas, well-developed internal micro porosity structure as well as the presence of a broad spectrum of surface functional groups ‎[16]. thus, locally produced wastes such as cow bones, saw dust and others were examined for preparing active carbon. because of the low cost of those wastes, a high percentage of carbonaceous contents and their abundance they were utilized to produce cost effective, efficient activated carbon and applicate it to remove heavy metals. https://doi.org/10.31699/ijcpe.2019.2.4 m. w. khalid and s. d. salman / iraqi journal of chemical and petroleum engineering 20,2 (2019) 23 32 46 2materials and methods 2.1. adsorbate technical grade potassium dichromate (k2cr2o7) of 99.8% purity provided by himedia, germany was used to preparing the stock solution of chromium. all solutions were prepared using distilled water. the stock of 1000 mg/l was prepared by adding (2.8269) gm of k2cr2o7 to a liter of dw; dilution law was used to prepare the required concentrations. 0.1 m hno3 and 0.1 m naoh were used to adjust the ph ‎[17] 2.2 chemicals and gases name formula assay (%) source or company usage nitrogen n2 99.9 local inert gas to prevent raw material combustion potassium hydroxide pellet koh 85 himedia, india chemical activating agent carbon dioxide co2 99.9 local physical activating agent hydrochloric acid hcl 2n england washing and neutralizing of ac potassium dichromate k2cr2o7 99.9 thomas baker, india chromium ions source nitric acid hno3 70 j.t.baker, holland solution ph adjustment sodium hydroxide naoh 99.5 didactic, spain solution ph adjustment 2.3. preparation and characterization of activated carbon cow bones (cb) was collected from local butchers, baghdad, iraq as waste. the preparation methodology of cbac is concise in fig. 1. the conditions that were used in cow bone charring were obtained from moreno-piraján ‎[18]. the surface area was analyzed using brunaure-emmettteller (bet: horiba, sa-900 series, usa) through nitrogen adsorption isotherm at 77 k. in order to determine the shape of the cbac surface, the samples were scanned using a scanning electron microscope (tescan, vega iii, czech republic). fig. 1. schematic diagram for the cbac preparation steps 2.4. design of experiments the experimental design usually used to efficiently map the set of experiments to be conducted and to serve the following: understand the effect of the factors and/or model the relationship between response and factors with a minimum of experiments ‎[19]. taguchi method was used in the optimization of the cbac production and modeling of adsorption process due to its efficiency compared to other methodologies and its robustness. statistica 10 (statsoft, inc. usa) was used to design the set of experiments. table 1 shows the l9 orthogonal array that was chosen (2 factors, 3 levels) for cbac preparation and table 2 shows the l25 array (4 factors, 4 levels) for chromium adsorption process. table 1. taguchi doe (l9 array) of cbac optimization no. activation temperature ( o c) ir 1 600 1:0.5 2 600 1:1 3 600 1:1.5 4 700 1:0.5 5 700 1:1 6 700 1:1.5 7 800 1:0.5 8 800 1:1 9 800 1:1.5 m. w. khalid and s. d. salman / iraqi journal of chemical and petroleum engineering 20,2 (2019) 23 32 47 table 2. taguchi doe (l25 array) of chromium adsorption experiments no. initial concentration (mg/l) contact time (minutes) temperature (c o ) solution ph 1 10 30 20 2 2 10 120 30 5 3 10 210 40 8 4 10 300 50 11 5 20 30 30 8 6 20 120 20 11 7 20 210 50 2 8 20 300 40 5 9 30 30 40 11 10 30 120 50 8 11 30 210 20 5 12 30 300 30 2 13 50 30 50 5 14 50 120 40 2 15 50 210 30 11 16 50 300 20 8 2.5. batch equilibrium studies bach mode adsorption experiments were conducted by adding a specific amount of adsorbent to a 100 ml chromium solution contained in a 100 ml capped plastic containers. the containers were placed in an isothermal shaker (jssi-300cl, jsr, korea) at an agitation speed of 180 rpm. the remaining concentration of chromium in each sample after adsorption at different times was determined by atomic-absorption spectroscopy (shimadzu aa6200, japan). all samples were filtered from the adsorbent with whatmen filter paper to make it carbon free. the chromium concentration adsorbed on cbac was predicted according to: ( ) (1) where qe is the adsorption capacity at equilibrium (mg/g), co and ce are the concentrations at initial and equilibrium conditions (mg/l) for chromium solution, respectively; v is the volume (l); and w is the weight (g) of cbac. 2.6. adsorption process modelling after adsorption batch experiments were run, the equilibrium concentrations (ce) were used to form a mathematical model that represents the adsorption process. this model relates ce as a response with the investigated factors which are: initial concentration, contact time, temperature, and solution ph. statistica 10 (statsoft, inc. usa) was utilized to form the model by nonlinear estimation method. this model was used to generate the equilibrium concentration at various conditions; these results were used in adsorption isotherm fitting, kinetics study, and adsorption thermodynamics. 2.7. adsorption isotherm two isotherm models (langmuir and freundlich) were used to fit the equilibrium data. the linear form of the langmuir ‎[20] model is: ( ) (2) where ce (mg/l) is the concentration of chromium at equilibrium; qe (mg/g) the equilibrium adsorption capacity; qm the adsorption capacity for a complete monolayer (mg/g); ka (l/mg) is the constant of adsorption equilibrium. the linear form of freundlich ‎[21] isotherm is: ( ) (3) the constants kf (mg/g) and n are the freundlich constants. 2.8. kinetic studies the adsorption rate constants were predicted from the pseudo-first-order and pseudo-second-order equations. for the pseudo-first-order, the lagergren ‎[22] the used expression is: ( ) (4) where qe and qt (mg/g) are the adsorption capacities equilibrium and at time t (min), respectively and k1 (1/min) is the adsorption constant. the linear form of the pseudo-second-order ‎[23] reaction can give by: (5) where the adsorption capacity of equilibrium (qe), and the constant of second order k2 (g/mg h) can be determined experimentally from the intercept and slope of t/qt versus t plot. 3results and discussion 3.1. cbac production and optimization the complete design array (l 9) for the surface area and yield as responses of cbac preparation with two factors, temperature of activation and impregnation ratio (ir)(char: koh wt: wt) from the experiments that were conducted are shown in table 3. m. w. khalid and s. d. salman / iraqi journal of chemical and petroleum engineering 20,2 (2019) 23 32 48 table 3. preparation of cbac experimental design array and the results for ssa and yield runs cbac preparation variables cbac preparation responses ir activation temperature (ᵒc) specific surface area (m 2 /gm) yield (%) 1 1:0.5 600 270.4 85.9 2 1:0.5 700 475.6 79.3 3 1:0.5 800 370.4 71.4 4 1:1 600 315.3 79.5 5 1:1 700 480.6 72.2 6 1:1 800 460.0 60.6 7 1:1.5 600 595.9 76.2 8 1:1.5 700 350.0 65.3 9 1:1.5 800 240.8 57.9 it was found that in cbac preparation the ssa increases as ir rises from 1:0.5 to 1:1. these results clarify that the reduction of koh occurs during the activation process, it was transformed to potassium oxide by a dehydration reaction. potassium oxide reacts with carbon dioxide that is provided during physical activation to form k2co3, which aids to form new pores and widen pores that were formed during chemical activation. so it was recognized that above 420 o c (melting point of koh) the surface area of carbon activated by koh is more than the area of carbon activated by k2co3 ‎[24]. when the ir reached to 1:1.5 the ssa increases at activation temperature of 600 o c, this may be due to lower potassium deposition on pores compared to the experiments of activation temperatures of 700 and 800 o c where the ssa decreased, this was probably due to excessive potassium hydroxide molecules decomposing into metal. as a result, metal deposition on the already developed pores might have occurred and lead to a reduction of the surface area ‎[25]. the relation between ssa, activation temperature, and impregnation ratio is shown in fig. 2a regarding the activation temperatures, it was perceived that as the temperature rises from 600 c o to 700 o c with ir of the range 1:0.51:1 the ssa increases with it. these results showed that as the activation temperature increases, the structure tends to become micro porous. that’s due to that porosity is formed by koh evaporation, therefore; as temperature increases, more koh evaporates which leads to micro porosity enhancement, except for the result of the experiments with ir of 1:1.5, this is may be explained by the excessive concentration of koh that led to the formation of wider or exploded pores which caused the declined ssa ‎[26]. on the other hand, ssa decreased at 800 c o , this is probably because high activating temperatures caused pore explosion that led to lower values of the specific surface area ‎[27]. (a) (b) fig. 2. a) effect of activation temperature and impregnation ratio on ssa b) effect of activation temperature and impregnation ratio on yield m. w. khalid and s. d. salman / iraqi journal of chemical and petroleum engineering 20,2 (2019) 23 32 49 in general, the cbac yield was found to be inversely proportional to both temperatures of activation and ir. as temperature elevate more volatile components will be released due to intensified dehydration and elimination reaction that increases c-koh and c-co2 reaction rate, which causes lower ‎[28]. as the ir value rises, koh amount increases, which lead to oxidation process promotion causing the carbon atoms gasification reaction to become more dominant, therefore; more weight of carbon would be lost ‎[24]. the relation between yield, activation temperature and impregnation ratio is shown in fig. 2b. 3.2. sem and bet analysis fig. 3 shows the sem images of cb (a) and cbac (b). it can be noticed that the cbac surface has developed pores in which there is a good probability for chromium to be adsorbed. the bet surface area was 595.9 m 2 /g. pore diameter in average was 3.46 nm, indicating that it was in the mesoporous region according to the international union of pure and applied chemistry (iupac). the pores are classified as micro pores (<2nm diameter), mesopores (2–50nm diameter) and macro pores (>50nmdiameter) ‎[29]. the cbac has a high surface area, which makes it more efficient for the removal of chromium. the high ssa of the cbac was a result of the used technique of activation. the activation process involved chemical and physical activating agents which are koh and co2 respectively. however, the developed pores during carbonization enhanced the surface area by diffusing more co2 and koh molecules inside the pores, therefore; the reaction between koh-carbon and co2-carbon promoted leading to more pores in the activated carbon. (a) (b) fig. 3. sem images, a) precursor b) cbac (magnifications: 1000x) 3.3. experimental design and empirical model the set of experiments that were designed by taguchi method and their results are shown in table 4 table 4. batch adsorption experiments and their response initial concentratio n (mg/l) time (min) temperature (c) ph equilibrium concentration (mg/l) 10 30 20 2 6.51 10 120 30 5 7.4 10 210 40 8 3.41 10 300 50 11 5.275 20 30 30 8 15.285 20 120 20 11 11.63 20 210 50 2 6.418 20 300 40 5 5.66 30 30 40 11 23.52 30 120 50 8 12.14 30 210 20 5 6.487 30 300 30 2 3.35 50 30 50 5 35.89 50 120 40 2 13.13 50 210 30 11 18.6 50 300 20 8 9.22 m. w. khalid and s. d. salman / iraqi journal of chemical and petroleum engineering 20,2 (2019) 23 32 4: in order to obtain the empirical model for the adsorption process the results from taguchi experimental design was used. y is the response variable, the obtained model with its four factors and their interaction is represented by: (6) where b0, b1, b2, b3 and b4 are the linear coefficients, b12, b13, b14, b23, b24 and b34 are the second-order interaction terms, b11, b22, b33 and b44 are the quadratic terms of each factor. x1, x2, x3 and x4 are the coded terms of initial chromium concentration, time, temperature and ph, respectively. the estimated values of the model coefficient, standard error of each model term and its p value are shown in table 5 table 5. model coefficients, standard error and terms p values estimate standard error pvalue b0 7.506 1.869 0.00008 b1 0.443 0.047 0.00000 b2 -0.084 0.006 0.00000 b3 -0.016 0.815 0.00003 b4 -0.836 0.203 0.00005 b12 -0.001 0.000 0.00000 b13 -0.003 0.000 0.00000 b14 0.025 0.002 0.00000 b23 0.0001 0.000 0.265 b24 0.001 0.000 0.00000 b34 -0.005 0.002 0.044 b11 -0.001 0.000 0.035 b22 0.0002 0.000 0.00000 b33 0.0007 0.001 0.498 b44 0.063 0.11 0.00000 as it can be seen from table.4 that b23 and b33 have an insignificant effect on model accuracy, due to their p values, which are larger than 0.05. 3.4. effects of factors a. effect of contact time and cr(vi) initial concentration the influence of adsorption time on chromium ions adsorbed by cbac was investigated and presented in fig. 4. it was observed that the chromium ions removal efficiency by cbac increased with the initial chromium ion concentration. the adsorption was fast at the initial stage because of the high driving force which induced the metal ions to transfer rapidly from the bulk solution to the surface of cbac ‎[17]. as time passed more active sited was occupied, this means less free active sites on the surface. alongside with the declined driving force that made the adsorption to take more time to reach equilibrium, because metal ions slowly diffused to the intra-particle pores of the adsorbent ‎[30]. thus, the adsorption rate is decreased. it is also clear from fig. 4 that removal efficiency improved as the initial concentration of cr (ii). because of the increased driving force of the concentration gradient ‎[31]. a similar trend of heavy metal adsorption, as a function of initial concentration, has also been reported previously ‎[32], ‎[33]. fig. 4. effect of contact time and initial concentration on removal efficiency b. effect of ph and temperature the solution initial ph is the most significant factor to investigate the adsorption characteristic of an adsorbent because it affects not only surface charge of the adsorbent, but also the ionization degree and adsorbate speciation ‎[34]. the effect of initial solution ph on chromium ion removal by cbac is presented in fig. 5. as the negative charge density on cbac surface increases due to cooh ionization, the adsorbed chromium will rise rapidly ‎[35]. at ph = 2, the efficiency on adsorption almost reached its maximum value. as temperature rises, the solution viscosity will slightly decrease, which enhances the diffusion rate of chromium into the pores of cbac ‎[36]. in addition to that, the high temperatures will break internal bonds at the edges of the active sites ‎[37], which aids the enhancement of adsorption efficiency of the cbac. fig. 5 illustrates the direct proportion between temperature and efficiency of adsorption. as it can be seen from fig. 5 that chromium adsorption on cbac is an exothermic process. m. w. khalid and s. d. salman / iraqi journal of chemical and petroleum engineering 20,2 (2019) 23 32 4; fig. 5. the effect of initial ph and temperature on adsorption efficiency 3.5. adsorption isotherm studies the correlation between bulk solution concentration of sorbate and the amount of adsorbed heavy metal ions on the cbac unit at equilibrium conditions is described functionally by the isotherms of adsorption. the adsorption isotherm was studied in order to understand the behavior of chromium ions in the solution – cbac interphase,. usually, adsorption isotherm analysis is conducted to find the fitter model to be used in equipment design purposes. table.6 summarizes the capacities of adsorption for monolayer coverage as implied by the langmuir model with the two isotherms constants and their correlation coefficients at 20, 30, 40 and 50 ◦ c. as it can be observed that freundlich model fitted adsorption data of cr(vi) more adequately due to higher r 2 values at all the mentioned temperature range, where r 2 was more than 0.95. fitting the freundlich isotherm refers to the heterogeneous surface energies and high values of kf indicate the high adsorption capacity of cbac for cr(vi) ‎[38]. all 1/n values were larger than 1 which is an indication of the chemical nature of the process ‎[39]. fig. 6 shows the plot of ln ce versus ln qe with temperature range of (20-50 o c). other studies had also confirmed the same results ‎[40], ‎[41]. table 6. values of freundlich and langmuir constants for cr(vi) adsorption on cbac langmuir temperature (cᵒ) kl (l/mg) qm (mg/g) r 2 kf (mg/g ) 1/n r 2 20 0.32 14.401 0.93 16.232 1.59 0.952 30 0.241 13.346 0.914 9.804 1.593 0.962 40 0.161 13.333 0.906 4.907 1.663 0.966 50 0.099 12.774 0.939 1.287 1.853 0.962 fig. 6. adsorption data fitted into freundlich isotherm at temperature range of (20-50 c o ) 3.6. kinetics studies to figure out the mechanism that controls the adsorption of chromium on cbac, such as physical interactions and chemical reaction, pseudo-first-order and pseudo-second-order equations were utilized to model the kinetics of adsorption. the comparison between the experimental and calculated concentration of equilibrium and correlation coefficients were used to evaluate kinetics equations fitting. as the difference between experimental equilibrium concentration (qe,exp) and calculated equilibrium concentration (qe,cal) get smaller and r2 goes to unity, the kinetic equation represents the adsorption more accurately. the kinetics were studied at different initial concentration of chromium. chromium adsorption obeyed pseudo-second order more clearly compared to pseudofirst order. pseudo-first order and pseudo-second order adsorption rate constants, calculated and experimental qe values for different initial concentration chromium are summarized in table 7. other researches had confirmed the same results ‎[37], ‎[42] and ‎[33]. table 7. comparison of the pseudo-first and pseudosecond order rate constants, and calculated and experimental qe values chromium adsorption on cbac for various initial concentrations initial concentration (mg/l) pseudo-first order pseudo-second order qe,exp (mg/g) k1 (1/min) qe,cal (mg/g) r 2 k2 (g/mg min) qe,cal (mg/g) r 2 10 3.45 0.014 3.836 0.972 0.02 3.339 0.991 20 7.388 0.01 5.419 0.929 0.013 7.865 0.993 30 11.232 0.011 7.496 0.945 0.019 10.68 0.997 40 14.96 0.006 7.888 0.931 0.025 13.979 0.998 50 18.864 0.005 9.185 0.975 0.026 18.511 0.999 m. w. khalid and s. d. salman / iraqi journal of chemical and petroleum engineering 20,2 (2019) 23 32 53 4conclusion in this study, cow bones active carbon showed a promising prospect in chromium adsorption from aqueous solution over a wide range of conditions, the optimum removal efficiency was 94.32%. highest ssa of cbac was 595.9 m 2 /g at the activation temperature of 600 o c and ir of 1:1.5. langmuir and freundlich isotherm models were utilized to fit the data of equilibrium and the equilibrium data for cbac were best represented by the freundlich isotherm at different temperatures with r 2 values more than 0.95. the kinetics of adsorption followed the pseudo second order kinetic model at various initial chromium concentrations; pseudo-second order kinetic model produced the highest r 2 values (more than 0.99). due to the high range of removal efficiencies, cbac can be used as a cost effective, inexpensive substitute to the commercial activated carbons. references [1] j. a. alnajar, a. a. kwaeri, r. h. sayhood, and a. h. slaymon, ―study the feasibility of alumina for the adsorption of metal ions from water,‖ iraqi j. chem. pet. eng., vol. 15, no. 3, pp. 37–50, 2014. [2] a. h. sulaymon, s. e. ebrahim, t. j. al musawi, and s. m. abdullah, ―removal of lead , cadmium , and mercury ions using biosorption,‖ iraqi j. chem. pet. eng., vol. 11, no. 2, pp. 1–13, 2010. [3] w. peng, h. li, y. liu, and s. song, ―a review on heavy metal ions adsorption from water by graphene oxide and its composites,‖ j. mol. liq., vol. 230, pp. 496–504, 2017. [4] a. a. el-bayaa, n. a. badawy, and e. a. alkhalik, ―effect of ionic strength on the adsorption of copper and chromium ions by vermiculite pure clay mineral,‖ j. hazard. mater., vol. 170, no. 3, pp. 1204–1209, 2009. [5] v. k. gupta and i. ali, ―removal of lead and chromium from wastewater using bagasse fly ash — a sugar industry waste,‖ j. ofcolloid interface sci., vol. 271, pp. 321–328, 2004. [6] f. an, r. wu, m. li, t. hu, j. gao, and z. yuan, ―removal of heavy metal ions by iminodiacetic acid functionalized d301 resin : kinetics , isotherms and thermodynamics,‖ react. funct. polym., vol. 118, no. february, pp. 42–50, 2017. [7] p. kanagaraj, a. nagendran, d. rana, t. matsuura, and s. neelakandan, ―separation of macromolecular proteins and rejection of toxic heavy metal ions by pei/csmm blend uf membranes,‖ int. j. biol. macromol., vol. 72, no. january 2015, pp. 223–229, 2014. [8] f. jos and i. mart, ―transport of chromium ( vi ) through a cyanex 921-supported liquid membrane from hcl solutions,‖ j. chem. technol. biotechnol., vol. 1053, no. february 2003, pp. 1048–1053, 2003. [9] p. kanagaraj et al., ―influence of n-phthaloyl chitosan on poly (ether imide) ultrafiltration membranes and its application in biomolecules and toxic heavy metal ion separation and their antifouling properties,‖ appl. surf. sci., vol. 239, no. february 2015, pp. 165–173, 2014. [10] g. nemeth, l. mlinarik, and a. torok, ―adsorption and chemical precipitation of lead and zinc from contaminated solutions in porous rocks : possible application in environmental protection,‖ j. african earth sci., vol. 122, no. october 2016, pp. 98–106, 2016. [11] h. sis and t. uysal, ―removal of heavy metal ions from aqueous medium using kuluncak ( malatya ) vermiculites and effect of precipitation on removal,‖ appl. clay sci., vol. 95, pp. 1–8, 2014. [12] r. h. salman, ―removal of manganese ions ( mn 2 + ) from a simulated wastewater by electrocoagulation / electroflotation technologies with stainless steel mesh electrodes : process optimization based on taguchi approach,‖ iraqi j. chem. pet. eng., vol. 20, no. 1, pp. 39–48, 2019. [13] s. mahdavi, m. jalali, and a. afkhami, ―heavy metals removal from aqueous solutions using tio2 , mgo , and al2o3 nanoparticles,‖ vol. 200, no. 3, pp. 448–470, 2016. [14] m. a. hashim, s. mukhopadhyay, j. narayan, and b. sengupta, ―remediation technologies for heavy metal contaminated groundwater,‖ j. environ. manage., vol. 92, no. 10, pp. 2355–2388, 2011. [15] j. pallarés, a. gonzález-cencerrado, and i. arauzo, ―production and characterization of activated carbon from barley straw by physical activation with carbon dioxide and steam,‖ biomass and bioenergy, vol. 115, no. january, pp. 64–73, 2018. [16] p. chingombe, b. saha, and r. j. wakeman, ―surface modification and characterisation of a coalbased activated carbon,‖ carbon n. y., vol. 43, pp. 3132–3143, 2005. [17] a. h. m. g. hyder, s. a. begum, and n. o. egiebor, ―adsorption isotherm and kinetic studies of hexavalent chromium removal from aqueous solution onto bone char,‖ j. environ. chem. eng., vol. 3, no. 2, pp. 1329–1336, 2014. [18] j. c. moreno-piraján, r. gómez-cruz, v. s. garcía-cuello, and l. giraldo, ―binary system cu ( ii )/ pb ( ii ) adsorption on activated carbon obtained by pyrolysis of cow bone study,‖ j. anal. appl. pyrolysis, vol. 89, pp. 122–128, 2010. [19] l. massart and b. vandeginste, chemometrics and qualimetrics in chemical engineering. newyork, ny: princeton press, 1991. [20] i. langmuir, ―the constitution and fundamental properties of solids and liquids.,‖ j. am. chem. soc., vol. 182, pp. 2221–2295, 1916. [21] h. freundlich, ―capillary anf colloid chemistry. by prof. h. freundlich. translated by h. stafford hatfield.,‖ j. phys. chem, vol. 57, pp. 385–470, 1925. http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/285 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/285 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/285 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/285 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/372 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/372 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/372 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/372 https://www.sciencedirect.com/science/article/pii/s0167732216315513 https://www.sciencedirect.com/science/article/pii/s0167732216315513 https://www.sciencedirect.com/science/article/pii/s0167732216315513 https://www.sciencedirect.com/science/article/pii/s0167732216315513 https://www.sciencedirect.com/science/article/pii/s0304389409008693 https://www.sciencedirect.com/science/article/pii/s0304389409008693 https://www.sciencedirect.com/science/article/pii/s0304389409008693 https://www.sciencedirect.com/science/article/pii/s0304389409008693 https://www.sciencedirect.com/science/article/pii/s0304389409008693 https://www.sciencedirect.com/science/article/pii/s0021979703010518 https://www.sciencedirect.com/science/article/pii/s0021979703010518 https://www.sciencedirect.com/science/article/pii/s0021979703010518 https://www.sciencedirect.com/science/article/pii/s0021979703010518 https://www.sciencedirect.com/science/article/abs/pii/s1381514817301359 https://www.sciencedirect.com/science/article/abs/pii/s1381514817301359 https://www.sciencedirect.com/science/article/abs/pii/s1381514817301359 https://www.sciencedirect.com/science/article/abs/pii/s1381514817301359 https://www.sciencedirect.com/science/article/abs/pii/s1381514817301359 https://www.sciencedirect.com/science/article/pii/s0141813014005510 https://www.sciencedirect.com/science/article/pii/s0141813014005510 https://www.sciencedirect.com/science/article/pii/s0141813014005510 https://www.sciencedirect.com/science/article/pii/s0141813014005510 https://www.sciencedirect.com/science/article/pii/s0141813014005510 https://www.sciencedirect.com/science/article/pii/s0141813014005510 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.903 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.903 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.903 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.903 https://www.sciencedirect.com/science/article/pii/s0169433214027810 https://www.sciencedirect.com/science/article/pii/s0169433214027810 https://www.sciencedirect.com/science/article/pii/s0169433214027810 https://www.sciencedirect.com/science/article/pii/s0169433214027810 https://www.sciencedirect.com/science/article/pii/s0169433214027810 https://www.sciencedirect.com/science/article/pii/s0169433214027810 https://www.sciencedirect.com/science/article/pii/s1464343x16301388 https://www.sciencedirect.com/science/article/pii/s1464343x16301388 https://www.sciencedirect.com/science/article/pii/s1464343x16301388 https://www.sciencedirect.com/science/article/pii/s1464343x16301388 https://www.sciencedirect.com/science/article/pii/s1464343x16301388 https://www.sciencedirect.com/science/article/pii/s1464343x16301388 https://www.sciencedirect.com/science/article/pii/s0169131714000969 https://www.sciencedirect.com/science/article/pii/s0169131714000969 https://www.sciencedirect.com/science/article/pii/s0169131714000969 https://www.sciencedirect.com/science/article/pii/s0169131714000969 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/514 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/514 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/514 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/514 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/514 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/514 https://www.tandfonline.com/doi/abs/10.1080/00986445.2012.686939 https://www.tandfonline.com/doi/abs/10.1080/00986445.2012.686939 https://www.tandfonline.com/doi/abs/10.1080/00986445.2012.686939 https://www.tandfonline.com/doi/abs/10.1080/00986445.2012.686939 https://www.sciencedirect.com/science/article/pii/s0301479711002064 https://www.sciencedirect.com/science/article/pii/s0301479711002064 https://www.sciencedirect.com/science/article/pii/s0301479711002064 https://www.sciencedirect.com/science/article/pii/s0301479711002064 https://www.sciencedirect.com/science/article/pii/s0961953418301041 https://www.sciencedirect.com/science/article/pii/s0961953418301041 https://www.sciencedirect.com/science/article/pii/s0961953418301041 https://www.sciencedirect.com/science/article/pii/s0961953418301041 https://www.sciencedirect.com/science/article/pii/s0961953418301041 https://www.sciencedirect.com/science/article/pii/s000862230500360x https://www.sciencedirect.com/science/article/pii/s000862230500360x https://www.sciencedirect.com/science/article/pii/s000862230500360x https://www.sciencedirect.com/science/article/pii/s000862230500360x https://www.sciencedirect.com/science/article/pii/s2213343714002735 https://www.sciencedirect.com/science/article/pii/s2213343714002735 https://www.sciencedirect.com/science/article/pii/s2213343714002735 https://www.sciencedirect.com/science/article/pii/s2213343714002735 https://www.sciencedirect.com/science/article/pii/s2213343714002735 https://www.sciencedirect.com/science/article/pii/s0165237010000902 https://www.sciencedirect.com/science/article/pii/s0165237010000902 https://www.sciencedirect.com/science/article/pii/s0165237010000902 https://www.sciencedirect.com/science/article/pii/s0165237010000902 https://www.sciencedirect.com/science/article/pii/s0165237010000902 https://pubs.acs.org/doi/pdf/10.1021/ja02268a002 https://pubs.acs.org/doi/pdf/10.1021/ja02268a002 https://pubs.acs.org/doi/pdf/10.1021/ja02268a002 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.5000454407 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.5000454407 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.5000454407 m. w. khalid and s. d. salman / iraqi journal of chemical and petroleum engineering 20,2 (2019) 23 32 53 [22] y.-s. ho, ―citation review of lagergren kinetic rate equation on adsorption reactions,‖ scientometrics, vol. 59, no. 1, pp. 171–177, 2004. [23] h. p. boehm, ―some aspects of the surface chemistry of carbon blacks and other carbons,‖ carbon n. y., vol. 32, no. 5, pp. 759–769, 1994. [24] y. sudaryanto, s. b. hartono, w. irawaty, h. hindarso, and s. ismadji, ―high surface area activated carbon prepared from cassava peel by chemical activation,‖ bioresour. technol., vol. 97, no. march 2005, pp. 734–739, 2006. [25] a. borhan, m. f. taha, and a. a. hamzah, ―characterization of activated carbon from wood sawdust prepared via chemical activation using potassium hydroxide,‖ adv. mater. res., vol. 832, pp. 132–137, 2014. [26] t. c. chandra, m. m. mirna, y. sudaryanto, and s. ismadji, ―adsorption of basic dye onto activated carbon prepared from durian shell: studies of adsorption equilibrium and kinetics,‖ chem. eng. j., vol. 127, no. 1–3, pp. 121–129, 2007. [27] a. nayak, b. bhushan, v. gupta, and p. sharma, ―chemically activated carbon from lignocellulosic wastes for heavy metal waste-water remediation: effect of activation conditions.,‖ j. colloid interface sci., vol. 493, pp. 228–240, 2017. [28] m. danish, r. hashim, m. n. m. ibrahim, and o. sulaiman, ―optimized preparation for large surface area activated carbon from date (phoenix dactylifera l.) stone biomass,‖ biomass and bioenergy, vol. 61, no. 320, pp. 167–178, 2014. [29] l. niazi, a. lashanizadegan, and h. sharififard, ―chestnut oak shells activated carbon: preparation, characterization and application for cr (vi) removal from dilute aqueous solutions,‖ j. clean. prod., vol. 185, no. 6, pp. 554–561, 2018. [30] i. ullah, r. nadeem, m. iqbal, and q. manzoor, ―biosorption of chromium onto native and immobilized sugarcane bagasse waste biomass,‖ ecol. eng., vol. 60, pp. 99–107, 2013. [31] e. malkoc, y. nuhoglu, and m. dundar, ―adsorption of chromium ( vi ) on pomace — an olive oil industry waste : batch and column studies,‖ j. hazard. mater., vol. 138, pp. 142–151, 2006. [32] e. demirbas, m. kobya, e. senturk, and t. ozkan, ―adsorption kinetics for the removal of chromium ( vi ) from aqueous solutions on the activated carbons prepared from agricultural wastes,‖ water sa, vol. 30, no. 4, pp. 533–539, 2004. [33] k. li and x. wang, ―bioresource technology adsorptive removal of pb ( ii ) by activated carbon prepared from spartina alterniflora : equilibrium , kinetics and thermodynamics,‖ bioresour. technol., vol. 100, no. 11, pp. 2810–2815, 2009. [34] m. imamoglu and o. tekir, ―removal of copper (ii) and lead (ii) ions from aqueous solutions by adsorption on activated carbon from a new precursor hazelnut husks,‖ desalination, vol. 228, pp. 108–113, 2008. [35] p. miretzky, c. munoz, and a. carrillo-chavez, ―experimental binding of lead to a low cost on biosorbent: nopal (opuntia streptacantha),‖ bioresour. technol., vol. 99, pp. 1211–1217, 2008. [36] f. boudrahem, ―batch sorption dynamics and equilibrium for the removal of lead ions from aqueous phase using activated carbon developed from coffee residue activated with zinc chloride,‖ j. environ. manage., vol. 90, pp. 3031–3039, 2009. [37] j. acharya, j. n. sahu, b. k. sahoo, c. r. mohanty, and b. c. meikap, ―removal of chromium ( vi ) from wastewater by activated carbon developed from tamarind wood activated with zinc chloride,‖ chem. eng. j., vol. 150, pp. 25–39, 2009. [38] m. b. desta, ―batch sorption experiments : langmuir and freundlich isotherm studies for the adsorption of textile metal ions onto teff straw ( eragrostis tef ) agricultural waste,‖ j. thermodyn., vol. 20, pp. 375–380, 2013. [39] n. singh, a. kumari, and c. balomajumder, ―modeling studies on mono and binary component biosorption of phenol and cyanide from aqueous solution onto activated carbon derived from saw dust,‖ saudi j. biol. sci., vol. 25, no. 7, pp. 1454–1467, 2016. [40] m. jameel, ―study of removal of pb , zn , cu and ni ions from iraqi factories wastewater using local porcelanite rocks,‖ natl. j. chem., vol. 39, pp. 445–454, 2010. [41] m. karnib, a. kabbani, h. holail, and z. olama, ―heavy metals removal using activated carbon , silica and silica activated carbon composite,‖ energy procedia, vol. 50, pp. 113–120, 2014. [42] y. li et al., ―removal of lead from aqueous solution by activated carbon prepared from enteromorpha prolifera by zinc chloride activation,‖ j. hazard. mater., vol. 183, no. 1–3, pp. 583–589, 2010. https://akademiai.com/doi/abs/10.1023/b%3ascie.0000013305.99473.cf https://akademiai.com/doi/abs/10.1023/b%3ascie.0000013305.99473.cf https://akademiai.com/doi/abs/10.1023/b%3ascie.0000013305.99473.cf https://www.sciencedirect.com/science/article/pii/0008622394900310 https://www.sciencedirect.com/science/article/pii/0008622394900310 https://www.sciencedirect.com/science/article/pii/0008622394900310 https://www.sciencedirect.com/science/article/pii/s0960852405002142 https://www.sciencedirect.com/science/article/pii/s0960852405002142 https://www.sciencedirect.com/science/article/pii/s0960852405002142 https://www.sciencedirect.com/science/article/pii/s0960852405002142 https://www.sciencedirect.com/science/article/pii/s0960852405002142 https://www.scientific.net/amr.832.132 https://www.scientific.net/amr.832.132 https://www.scientific.net/amr.832.132 https://www.scientific.net/amr.832.132 https://www.scientific.net/amr.832.132 https://www.sciencedirect.com/science/article/pii/s1385894706003858 https://www.sciencedirect.com/science/article/pii/s1385894706003858 https://www.sciencedirect.com/science/article/pii/s1385894706003858 https://www.sciencedirect.com/science/article/pii/s1385894706003858 https://www.sciencedirect.com/science/article/pii/s1385894706003858 https://www.sciencedirect.com/science/article/pii/s0021979717300322 https://www.sciencedirect.com/science/article/pii/s0021979717300322 https://www.sciencedirect.com/science/article/pii/s0021979717300322 https://www.sciencedirect.com/science/article/pii/s0021979717300322 https://www.sciencedirect.com/science/article/pii/s0021979717300322 https://www.sciencedirect.com/science/article/pii/s0961953413005102 https://www.sciencedirect.com/science/article/pii/s0961953413005102 https://www.sciencedirect.com/science/article/pii/s0961953413005102 https://www.sciencedirect.com/science/article/pii/s0961953413005102 https://www.sciencedirect.com/science/article/pii/s0961953413005102 https://www.sciencedirect.com/science/article/pii/s0959652618306772 https://www.sciencedirect.com/science/article/pii/s0959652618306772 https://www.sciencedirect.com/science/article/pii/s0959652618306772 https://www.sciencedirect.com/science/article/pii/s0959652618306772 https://www.sciencedirect.com/science/article/pii/s0959652618306772 https://www.sciencedirect.com/science/article/abs/pii/s0925857413002796 https://www.sciencedirect.com/science/article/abs/pii/s0925857413002796 https://www.sciencedirect.com/science/article/abs/pii/s0925857413002796 https://www.sciencedirect.com/science/article/abs/pii/s0925857413002796 https://www.sciencedirect.com/science/article/pii/s0304389406005383 https://www.sciencedirect.com/science/article/pii/s0304389406005383 https://www.sciencedirect.com/science/article/pii/s0304389406005383 https://www.sciencedirect.com/science/article/pii/s0304389406005383 https://journals.co.za/content/waters/30/4/ejc116177 https://journals.co.za/content/waters/30/4/ejc116177 https://journals.co.za/content/waters/30/4/ejc116177 https://journals.co.za/content/waters/30/4/ejc116177 https://journals.co.za/content/waters/30/4/ejc116177 https://www.sciencedirect.com/science/article/pii/s0960852408010894 https://www.sciencedirect.com/science/article/pii/s0960852408010894 https://www.sciencedirect.com/science/article/pii/s0960852408010894 https://www.sciencedirect.com/science/article/pii/s0960852408010894 https://www.sciencedirect.com/science/article/pii/s0960852408010894 https://www.sciencedirect.com/science/article/pii/s0011916408002361 https://www.sciencedirect.com/science/article/pii/s0011916408002361 https://www.sciencedirect.com/science/article/pii/s0011916408002361 https://www.sciencedirect.com/science/article/pii/s0011916408002361 https://www.sciencedirect.com/science/article/pii/s0011916408002361 https://www.sciencedirect.com/science/article/pii/s0960852407002350 https://www.sciencedirect.com/science/article/pii/s0960852407002350 https://www.sciencedirect.com/science/article/pii/s0960852407002350 https://www.sciencedirect.com/science/article/pii/s0960852407002350 https://www.sciencedirect.com/science/article/pii/s0301479709001108 https://www.sciencedirect.com/science/article/pii/s0301479709001108 https://www.sciencedirect.com/science/article/pii/s0301479709001108 https://www.sciencedirect.com/science/article/pii/s0301479709001108 https://www.sciencedirect.com/science/article/pii/s0301479709001108 https://www.sciencedirect.com/science/article/pii/s1385894708007857 https://www.sciencedirect.com/science/article/pii/s1385894708007857 https://www.sciencedirect.com/science/article/pii/s1385894708007857 https://www.sciencedirect.com/science/article/pii/s1385894708007857 https://www.sciencedirect.com/science/article/pii/s1385894708007857 http://downloads.hindawi.com/journals/jtd/2013/375830.pdf http://downloads.hindawi.com/journals/jtd/2013/375830.pdf http://downloads.hindawi.com/journals/jtd/2013/375830.pdf http://downloads.hindawi.com/journals/jtd/2013/375830.pdf http://downloads.hindawi.com/journals/jtd/2013/375830.pdf https://www.sciencedirect.com/science/article/pii/s1319562x16000097 https://www.sciencedirect.com/science/article/pii/s1319562x16000097 https://www.sciencedirect.com/science/article/pii/s1319562x16000097 https://www.sciencedirect.com/science/article/pii/s1319562x16000097 https://www.sciencedirect.com/science/article/pii/s1319562x16000097 https://www.sciencedirect.com/science/article/pii/s1319562x16000097 https://www.iasj.net/iasj?func=article&aid=16223 https://www.iasj.net/iasj?func=article&aid=16223 https://www.iasj.net/iasj?func=article&aid=16223 https://www.iasj.net/iasj?func=article&aid=16223 https://www.sciencedirect.com/science/article/pii/s1876610214007504 https://www.sciencedirect.com/science/article/pii/s1876610214007504 https://www.sciencedirect.com/science/article/pii/s1876610214007504 https://www.sciencedirect.com/science/article/pii/s1876610214007504 https://www.sciencedirect.com/science/article/pii/s0304389410009489 https://www.sciencedirect.com/science/article/pii/s0304389410009489 https://www.sciencedirect.com/science/article/pii/s0304389410009489 https://www.sciencedirect.com/science/article/pii/s0304389410009489 m. w. khalid and s. d. salman / iraqi journal of chemical and petroleum engineering 20,2 (2019) 23 32 54 الكروم بواسطة كاربون منشط منتج من عظام البقرامتزاز أيونات الخالصة نتيجة لالستعماالت الواسعة لمكروم في الصناعة، باإلضافة الى أن الكروم عنصر مسرطن، وجب البحث عن طريقو فعالو واقتصاديو إلزالتو من المياه العادمة. في ىذه الدراسة، تم استخدام عظام البقر، كماده اوليو رخيصة، إلنتاج الكاربون المنشط. تم تشخيص الكاربون المنتج بالمجير االلكتروني لمتحقق من شكمو السطحي متر مربع/ 555.5( لمعرفة مساحتو السطحية. أفضل مساحو سطحيو تم الحصول عمييا betوتم استخدام ال) .1.1.5درجو سيمزيو كجرارة تفعيل و نسبة تصبيغ 600غم ب الكاربون المنتج من عظام البقر المتزاز الكروم من المحاليل المائية. تم دراسة تأثير العوامل تم استخدام دقيقو(، درجة الحرارة 300-30ممغم/لتر(، وقت االمتزاز ) 50-10األتية مع مدياتيا. التركيز االولي لمكروم ) زاز رياضيا بواسطة معادلو قياسيو (. تم تمثيل عممية االمت11-2درجو سيمزيو( واالس الييدروجيني ) 20-50) تجريبيو. تم استخدام معادلة النغماير وفريندليتش لقولبة عممية االمتزاز، حيث كانت العممية منطبقة أكثر عمى نموذج فريندليتش. استخدمت معادلة الدرجة األولى والدرجة الثانية لدراسة حركيو االمتزاز، حيث كان االمتزاز .%54.32لة الدرجة الثانية. أفضل كفاءه امتزاز كانت متوافق أكثر مع معاد . امتزاز، كاربون منشط، عظام بقر، الكروم، تفعيل فيزيائي كيميائي. الكممات الدالة available online at https://ijcpe.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.19 no.1 (march 2018) 45– 49 issn: 1997-4884 corresponding authors: nada sadoon ahmedzeki, email: dr_ahmedzeki@yahoo.com, sattar jalil hussein, email: na, waqar abdulwahid abdulnabi, email: engweqar@yahoo.com iraqi journal of chemical and petroleum engineering synthesis of nano crystalline gamma alumina from waste cans nada sadoon ahmedzeki a , sattar jalil hussein b and waqar abdulwahid abdulnabi a a chemical engineering department college of engineering university of baghdad – iraq b petroleum research and development center, ministry of oil-baghdad-iraq abstract in the present study waste aluminium cans were recycled and converted to produce alumina catalyst. these cans contain more than 98% aluminum oxide in their structure and were successfully synthesized to produce nano sized gamma alumina under mild conditions. a comprehensive study was carried out in order to examine the effect of several important parameters on maximum yield of alumina that can be produced. these parameters were reactants mole ratios (1.5, 1.5, 2, 3, 4 and 5), sodium hydroxide concentrations (10, 20, 30, 40, 50 and 55%) and weights of aluminum cans (2, 4, 6, 8 and 10 g). the compositions of alumina solution were determined by atomic absorption spectroscopy (aas); and maximum yield of alumina solution was 96.3% obtained at 2 mole ratios of reactants, 40% sodium hydroxide concentrations and 10g of aluminum cans respectively. gamma alumina was acquired by hydrothermal treatment of alumina solution at ph 7 and calcination temperature of 550 ºc. the prepared catalyst was characterized by x-ray diffraction (xrd), n2 adsorption/ desorption isotherms, x-ray fluorescence (xrf) and atomic force microscopy (afm). results showed good crystallinity of alumina as described by xrd patterns, with surface area of 311.149 m 2 /g, 0.36 cm 3 /g pore volume, 5.248 nm pore size and particle size of 68.56 nm respectively. keywords: gamma-alumina, aluminum cans, nano size materials, waste recycling this is an open access article under the cc by-nc license https://creativecommons.org/licenses/by-nc/4.0/ 1introduction alumina has many potential applications in industries and high-tech sectors due to high surface area, porosity and good mechanical properties. numerous methods had been experienced for synthesis of alumina which were cost effective, requires conditions of high temperatures and pressures ‎[1] such as bayer process ‎[2], sol-gel method ‎[3], control precipitation method from aluminum salts ‎[4] and extraction of alumina from kaoline ‎[5]. production of valuable materials from the recycle of waste materials is a process of dual benefit for reducing the accumulated amount of wastes from one side and to obtain a facile way for synthesizing new product having an important application on industrial scale on the other side ‎[6]. liu et al. (2011) ‎[7] utilized the recycling of aluminum beverage cans as a raw material to prepare micron-sized α -alumina by sol–gel method. aluminum cans were reacted with ethanol to produce aluminum ethoxide which was converted to α-al2o3 by calcinations at 900 ºc for 2 h. they analyzed the presence of some impure oxides and suggested purification of the ethoxide by vacuum distillation method. asencios and sun-kou (2012) [8] prepared γ-al2o3 by precipitation of sodium aluminate (which was derived from aluminum scrap) with sulfuric acid and calcinations at 500 ºc. the effect of ph, aging time and calcinations temperature were studied on the physicochemical properties of alumina produced. the presence of various alumina phases was observed within thermal treatment step. the result showed that alumina with higher surface area and smaller pores were produced at low ph values. the prepared alumina with 371 m 2 /g surface area was used for the adsorption of cd(ii), zn(ii) and pb(ii) from aqueous solution. chotisuwan et al. (2012) ‎[3] synthesized a mesoporous alumina by template-free solgel method from aluminum isopropoxide and aluminum hydroxide from waste aluminum cans. a high surface area alumina was produced (421-556 m 2 /g) at calcinations temperature of 500ºc and it was employed as a catalyst support for the oxidation of toluene. sheel et al. (2016) ‎[1] investigated the preparation of alumina from industrial cans by acid and alkali method. they showed that acid method is more convenient and preferred to prepare alumina than alkali method because of its higher product quality and quantity. the aim of this work is to synthesize gamma alumina from waste aluminum cans under mild conditions. a comprehensive study was carried out in order to examine the effect of several important parameters on maximum yield of alumina that can be produced. these parameters were reactants mole ratios, sodium hydroxide concentrations and weights of aluminum cans. https://creativecommons.org/licenses/by-nc/4.0/ n. s. ahmedzeki, et al./ iraqi journal of chemical and petroleum engineering91,9 (2018) 45-49 64 2experimental 2.1. preparation of nano γ-al2o3 waste aluminum cans were washed with 50% sulfuric acid to remove paint films which may inhibit the contact between reactants. these cans were reacted with 40% sodium hydroxide solution at ambient condition in a batch reactor. sodium aluminate solution is prepared from this reaction. this solution was filtered and its ph value was adjusted at 7 using concentrated hydrochloric acid. this solution was left at 80º c for 6 h. aluminum hydroxide gel was obtained from this step; the gel was washed many times with deionized water in order to get rid of sodium chloride salts that may dissolve in the solution. the solution were filtered and dried at 80º c for 6 h. finally the sample was ground and calcined at 550º c for 3 h in air at a heating rate of 1º c/min. 2.2. characterization of catalyst x-ray diffraction analysis of sample was conducted in order to check its crystallinity by x-ray diffractometer (shimadzu srd 6000, japan) located at research center of materials/ ministry of science and technology using cu radiation with wave length of 1.54060 cm -1 , in the 2θ range of 10-80º. the chemical compositions of produced catalyst were estimated by x-ray fluorescence performed at college of science / department of geology/ baghdad university. particles size of sample and the morphology of their surface were implemented by atomic force microscopy (afm) located in college of science / department of chemistry/ baghdad university. bet surface area, pore volume and pore size of sample were determined from nitrogen adsorptiondesorption isotherm conducted at petroleum research and development center/ ministry of oil. 3results and discussion 3.1. effect of reactants mole ratio the effect of naoh/al mole ratios on alumina yield at 40% naoh concentration and 4 g of aluminum cans were studied to find out the best values that will give optimum recovery of alumina. the mole ratios of reactants were more than the stoichiometric quantities at values of 1.5, 2, 3, 4 and 5. usually in any recovery process, excess amounts of reactants are usually required because the stoichiometric quantities do not offer the optimum recovery ‎[9]. alumina yield (wt. %) was defined as [10]: ( ) (1) where; and were the mass of aluminum in the precursor and product respectively. fig. 1. the effect of reactants mole ratios on alumina yield as shown in fig. 1, alumina yield was found to increase initially from 38.5 to 91.9 % with increasing the reactants mole ratios from 1.5 to 2.further increase in reactants mole ratios showed a declining trend of alumina recovery to about 21% at mole ratio of 5. the equations for complete reactions may be proposed as the following: ( ) ( ) ( ) ( ) ( )) ( ) (2) ( ) ( )) ( ) ( ) ( ) ( ) ( ) (3) ( ) ( ) ( ) ( ) (4) ( ) ( ) ( ) (5) more boehmite will be produced with the increasing of naoh /al molar ratio. this is due to the conversion of the aluminium precursor into al(oh)3 which will be hydrothermally treated to produce gamma alumina phase. the chemical reactions were illustrated in equations 1 to 4. further excess of naoh/al mole ratio, resulted in the drying of sodium aluminate which will become as a solid mass so that reducing alumina yield with additional excess of naoh amounts. this trend agrees with bell ‎[10], but sodium aluminate was extracted from aluminium nitrate without acid addition. during this study, it may be noted that with increasing the ratio of reactants, the yield percent initially increased and then decreased beyond a certain quantity. this may be due to the fact that higher dissolution will be observed with increasing alkalinities; however, the rate of aluminium cans dissolution will be decreased with additional increasing of naoh concentrations due to the loss amount of water in the mixture and as a result a solid mass of sodium aluminate will be formed. thus to obtain an optimum dissolution of alumina from these cans, a compromise between alkalinities and n. s. ahmedzeki, et al./ iraqi journal of chemical and petroleum engineering91,9 (2018) 45-49 64 hydroxide ions concentrations had to be confirmed in the reacted solution. 3.2. effect of sodium hydroxide concentration to investigate the influence of the concentrations of the sodium hydroxide solution on alumina production, an experimental study was carried out at different concentrations of naoh solution (10, 20, 30, 40, 50 and 55%), at constant reactants mole ratio (of 2) and aluminum cans weight (4 g). as shown in fig. 2, a sharp increase in alumina yield from 25.8 to 91.9 % was occurred with increasing the concentration of naoh solution from 10% to 40%, it was then followed an insignificant decrease in alumina recovery to about 79 % as naoh concentration increased to 55%. fig. 2. alumina yield as a function of naoh concentration the reaction between aluminum cans and water formed a dense film of protective oxide that covering the surface of these cans. the charge of this film was positive in the neutral solutions and it was easily dissolved in alkaline solutions generating hydrogen gas at ambient conditions. it can be suggested that at low naoh percentage, complete reaction cannot be obtained because of low rate of reaction. higher naoh concentration accelerated the hydrolysis of aluminum because the evolved hydrogen bubbles inhibit the precipitation of sodium aluminate from attaching on the aluminum surface reacted ‎[11]. anderson et al. (2003) ‎[12] proposed that naoh plays as a catalyst for aluminum hydrolysis and enhances the generating rate of hydrogen bubbles which increase agitation of the mixture and promote the reaction. as can be seen from fig. 2, the concentrated naoh solutions resulted in low alumina recovery, this may be attributed to the less amounts of water that are present for aluminum cans dissolution causing low yield. the reduction in alumina recovery up to 40% naoh concentration could be explained by the fact that sodium aluminate is less soluble in concentrated solutions. considering this aspect it was clear that the presence of adequate amounts of naoh as well as water strongly affects the dissolution kinetics essential for keeping the sodium aluminate in dissolved manner. 3.3. effect of aluminum cans weight figure 3 shows the behavior of alumina recovery as a function of aluminum cans weight (2, 4, 6, 8 and 10 g) at naoh concentration of 40% and naoh/ al cans of 2. alumina yield increased from 91.9 to reach a maximum value of 96.3 % as the weight of cans increased from 4 to 10 g. fig. 3 the variation of aluminum yield with different weights of aluminum cans as shown in fig. 3 and according to equations 1-4, it is clear that alumina yield is increased by increasing the initial amounts of aluminum cans precursor. it is well known that increasing the reactants concentrations increases the rate of reaction so that the reaction occurs more quickly. the increase in alumina yield as the can weight is increased may be attributed to the increase in the number of molecules that are ready for reaction ‎[13]. 4characterization of nano γ-al2o3 4.1. x–ray diffraction (xrd) the results of xrd patterns for the synthesized alumina can be referred to the formation of γ-al2o3as a single phase through the comparison with the powder diffraction data [jcps 29-0063]. comparison revealed that the preparation method was successfully synthesized gamma alumina material through the recycle of waste aluminum cans. fig. 4. xrd pattern of the prepared alumina n. s. ahmedzeki, et al./ iraqi journal of chemical and petroleum engineering91,9 (2018) 45-49 64 as shown in fig. 4, the xrd peaks can be assigned to gamma alumina structure characterized by 2θ at 66.87, 45.85 with broad peak at 37.42ºrespectively. it can be seen that these peaks tend to be amorphous due to their low intensities ‎[14]. the degree of relative crystallinity of the synthesized alumina was determined according to equation 6 ‎[15]. ∑ ∑ (6) according to equation 2, it was clear that the calculated relative crystallinity is 91.4 referring to the crystalline gamma alumina product and the calculated crystallite size was as 4.542 nm. 4.2. surface area and pore volume analysis surface area of sample calcined at 550ºc was 311.149m 2 /g which refers to the crystalline porous structure of the prepared alumina. pore volume of the sample and pore size of the sample were 0.36 cm 3 /g and 5.248 nm respectively. as reported in other studies ‎[16], ‎[17], maximum surface areas were obtained from smaller crystallite sizes. these crystallites contained high proportion of small pores. increasing calcinations temperatures led to the increase in the rate of evaporation of water and gases (oh bond and co gas) entrapped in the small pores towards larger ones and then to the bulk causing a drop in pressure. this pressure drop would be resulted in a partial loss of surface area due to the collapse of part of the pores. 4.3. atomic force microscopy (afm) to investigate the topography of the prepared alumina afm test was utilized. fig. 5 and fig. 6 showed topographical images on two and three-dimensional surface profile of alumina prepared at ph 7 and calcined at 550 ºc. fig. 5. two-dimensional image of the surface of synthesized alumina fig. 6. three-dimensional image of the surface of synthesized alumina particles of sizes in the range of 1 to 100 nm are classified as nano materials ‎[18]. fig. 7 illustrates the particles size distribution of synthesized alumina. these results confirmed that the prepared alumina is in the nano size region for the range of the diameters between 45 90 nm. most volume percentage of particles is 16.81 % at size distribution of 80 nm particles size at 25% volume percentage is around 60 nm; while its size at 50 and 75% is less than 80 nm. the average particle size is 68.56 nm. fig. 7. granularity cumulation distribution report of synthesized alumina 4.4. x-ray fluorescence (xrf) alumina with high purity was confirmed by xrf analysis. the structural formula of prepared sample is listed in table 1. table 1. chemical composition of synthesized alumina symbol element wt% al2o3 aluminum 79.46 na2o sodium 4.226 cl chlorine 4.186 sio2 silicon 1.000 n. s. ahmedzeki, et al./ iraqi journal of chemical and petroleum engineering91,9 (2018) 45-49 64 the presence of nacl salt in alumina structure affected the crystallinity of this sample but did not affect the surface area. the pronounced encouraging results are promising for adopting the present study for future applications. 5conclusion nano sized gamma alumina with purity of about 80% was successfully produced from waste aluminum cans. maximum yield of 96.3% alumina solution was obtained at 2 mole reactants ratio, 40% sodium hydroxide concentration and 10 g of aluminium cans respectively. the method adopted announced the preparation of potential material with striking results; high surface area of 311.149m 2 /g, 0.36 cm 3 /g pore volume, 5.248 nm pore size and particle size of 68.56 nm respectively. these results are promising for fruitful recycling of waste cans and in the boundaries of the green technology. acknowledgment the authors are grateful to the ministry of oil in iraq / petroleum research and development center for the financial support of the phd degree project. references [1] sheel, t. k., poddar, p., murad, a. w., neger, a. t., & chowdhury, a. s., 2016. preparation of aluminum oxide from industrial waste can available in bangladesh environment: sem and edx analysis. journal of advanced chemical engineering, 6(2). [2] mohammed, a.-h.. k., ibrahim, a. & madhhoor, m.g., 2007. alpha-alumina extraction from al-ga’ara bauxite. iraqi journal of chemical and petroleum enginnering, 8(2). [3] chotisuwan, s., sirirak, a., har-wae, p., & wittayakun, j., 2012. mesoporous alumina prepared from waste aluminum cans and used as catalytic support for toluene oxidation. materials letters, 70, pp.125–127. [4] sarsenbay, g., myltykbaeva, l. a, abdulwalyev, r. a, & sukurov, b. m., 2013. influence of the precipitating reagents and dispersants on the formation nanoaluminum hydroxide. , 2013(october), pp.11–15. [5] asenciosa, y.j.o. & sun-koub, m.r., 2012. “synthesis of high-surface-area gamma-al2o3 from aluminum scrap and its use for the adsorption of metals : pb ( ii ), cd ( ii ) and zn ( ii ). optical materials, 34(9), pp.1553–1557. [6] birnin-yauri, a.u & aliyu, m., 2014. synthesis and analysis of potassium aluminium sulphate ( alum ) from waste aluminium can. , 1(8), pp.1–6. [7] liu, w., niu, t., yang, j., wang, y., hu, s., dong, y., & xu, h., 2011. preparation of micron-sized alumina powders from aluminium beverage can by means of sol-gel process. micro and nano letters, 6(10), pp.852–854. [8] asenciosa, y.j.o. & sun-koub, m.r., 2012. “synthesis of high-surface-area gamma-al2o3 from aluminum scrap and its use for the adsorption of metals : pb ( ii ), cd ( ii ) and zn ( ii ). optical materials, 34(9), pp.1553–1557. [9] das, b. r., dash, b., tripathy, b. c., bhattacharya, i. n., & das, s. c., 2007. production of g-alumina from waste aluminium dross. minerals engineering, 20, pp.252–258. [10] bell, t. e., gonzalez-carballo, j. m., tooze, r. p., & torrente-murciano, l., 2015. single-step synthesis of nanostructured [gamma]-alumina with solvent reusability to maximise yield and morphological purity. j. mater. chem. a, 3, pp.6196–6201. [11] zou, h., chen, s., zhao, z., & lin, w., 2013. hydrogen production by hydrolysis of aluminum. journal of alloys and compounds, 578, pp.380–384. [12] andersen, e. r., & andersen, e. j. (2003). method for producing hydrogen. u.s. patent no. 6, 506,360 b1. u.s. patent and trademark office, washington, dc. [13] crowe, by j. & bradshaw, t., 2010. chemistry for the biosciences_ the essential concepts, oup oxford; 2 edition. [14] du, x., wang, y., su, x., & li, j., 2009. influences of ph value on the microstructure and phase transformation of aluminum hydroxide. powder technology, 192(1), pp.40–46. [15] alrubaye r. "generation and characterization of ctalytic films of zeolite y and zsm-5 on fecr alloy metal " : ph.d. thesis , university of manchester, 2013. [16] chen, y. f., lee, c. y., yeng, m. y., & chiu, h. t., 2003. the effect of calcination temperature on the crystallinity of tio2 nanopowders. journal of crystal growth, 247(3–4), pp.363–370. [17] richardson, j.t., 1989. principles of catalysts development, plenum, new york and london. [18] tiwari, a. & tiwari, a., 2014. bioengineered nanomaterials, crc press, boca raton, london and new york. https://www.omicsonline.org/open-access/preparation-of-aluminum-oxide-from-industrial-waste-can-available-inbangladesh-environment-sem-and-edx-analysis-2090-4568-1000152.pdf https://www.omicsonline.org/open-access/preparation-of-aluminum-oxide-from-industrial-waste-can-available-inbangladesh-environment-sem-and-edx-analysis-2090-4568-1000152.pdf https://www.omicsonline.org/open-access/preparation-of-aluminum-oxide-from-industrial-waste-can-available-inbangladesh-environment-sem-and-edx-analysis-2090-4568-1000152.pdf https://www.omicsonline.org/open-access/preparation-of-aluminum-oxide-from-industrial-waste-can-available-inbangladesh-environment-sem-and-edx-analysis-2090-4568-1000152.pdf https://www.omicsonline.org/open-access/preparation-of-aluminum-oxide-from-industrial-waste-can-available-inbangladesh-environment-sem-and-edx-analysis-2090-4568-1000152.pdf https://www.iasj.net/iasj?func=fulltext&aid=24613 https://www.iasj.net/iasj?func=fulltext&aid=24613 https://www.iasj.net/iasj?func=fulltext&aid=24613 https://www.iasj.net/iasj?func=fulltext&aid=24613 https://www.sciencedirect.com/science/article/pii/s0167577x11013796 https://www.sciencedirect.com/science/article/pii/s0167577x11013796 https://www.sciencedirect.com/science/article/pii/s0167577x11013796 https://www.sciencedirect.com/science/article/pii/s0167577x11013796 https://www.sciencedirect.com/science/article/pii/s0167577x11013796 http://file.scirp.org/pdf/msce_2013110710023781.pdf http://file.scirp.org/pdf/msce_2013110710023781.pdf http://file.scirp.org/pdf/msce_2013110710023781.pdf http://file.scirp.org/pdf/msce_2013110710023781.pdf https://www.sciencedirect.com/science/article/pii/s0169433212011130 https://www.sciencedirect.com/science/article/pii/s0169433212011130 https://www.sciencedirect.com/science/article/pii/s0169433212011130 https://www.sciencedirect.com/science/article/pii/s0169433212011130 https://www.sciencedirect.com/science/article/pii/s0169433212011130 http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.673.9926&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.673.9926&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.673.9926&rep=rep1&type=pdf http://digital-library.theiet.org/content/journals/10.1049/mnl.2011.0491 http://digital-library.theiet.org/content/journals/10.1049/mnl.2011.0491 http://digital-library.theiet.org/content/journals/10.1049/mnl.2011.0491 http://digital-library.theiet.org/content/journals/10.1049/mnl.2011.0491 http://digital-library.theiet.org/content/journals/10.1049/mnl.2011.0491 https://www.sciencedirect.com/science/article/pii/s0169433212011130 https://www.sciencedirect.com/science/article/pii/s0169433212011130 https://www.sciencedirect.com/science/article/pii/s0169433212011130 https://www.sciencedirect.com/science/article/pii/s0169433212011130 https://www.sciencedirect.com/science/article/pii/s0169433212011130 https://www.sciencedirect.com/science/article/abs/pii/s089268750600238x https://www.sciencedirect.com/science/article/abs/pii/s089268750600238x https://www.sciencedirect.com/science/article/abs/pii/s089268750600238x https://www.sciencedirect.com/science/article/abs/pii/s089268750600238x http://pubs.rsc.org/-/content/articlehtml/2015/ta/c4ta06692h http://pubs.rsc.org/-/content/articlehtml/2015/ta/c4ta06692h http://pubs.rsc.org/-/content/articlehtml/2015/ta/c4ta06692h http://pubs.rsc.org/-/content/articlehtml/2015/ta/c4ta06692h http://pubs.rsc.org/-/content/articlehtml/2015/ta/c4ta06692h https://www.sciencedirect.com/science/article/pii/s0925838813014138 https://www.sciencedirect.com/science/article/pii/s0925838813014138 https://www.sciencedirect.com/science/article/pii/s0925838813014138 https://patents.google.com/patent/us6638493b2/en https://patents.google.com/patent/us6638493b2/en https://patents.google.com/patent/us6638493b2/en https://patents.google.com/patent/us6638493b2/en https://books.google.iq/books?hl=en&lr=&id=vxmnbaaaqbaj&oi=fnd&pg=pp1&dq=chemistry+for+the+biosciences_+the+essential+concepts&ots=munj9pb97p&sig=x8rgavylzdwppf2uwqb2mkqvrai&redir_esc=y#v=onepage&q=chemistry%20for%20the%20biosciences_%20the%20essential%20concepts&f=false https://books.google.iq/books?hl=en&lr=&id=vxmnbaaaqbaj&oi=fnd&pg=pp1&dq=chemistry+for+the+biosciences_+the+essential+concepts&ots=munj9pb97p&sig=x8rgavylzdwppf2uwqb2mkqvrai&redir_esc=y#v=onepage&q=chemistry%20for%20the%20biosciences_%20the%20essential%20concepts&f=false https://books.google.iq/books?hl=en&lr=&id=vxmnbaaaqbaj&oi=fnd&pg=pp1&dq=chemistry+for+the+biosciences_+the+essential+concepts&ots=munj9pb97p&sig=x8rgavylzdwppf2uwqb2mkqvrai&redir_esc=y#v=onepage&q=chemistry%20for%20the%20biosciences_%20the%20essential%20concepts&f=false https://www.sciencedirect.com/science/article/pii/s0032591008005226 https://www.sciencedirect.com/science/article/pii/s0032591008005226 https://www.sciencedirect.com/science/article/pii/s0032591008005226 https://www.sciencedirect.com/science/article/pii/s0032591008005226 https://www.escholar.manchester.ac.uk/api/datastream?publicationpid=uk-ac-man-scw:212059&datastreamid=full-text.pdf https://www.escholar.manchester.ac.uk/api/datastream?publicationpid=uk-ac-man-scw:212059&datastreamid=full-text.pdf https://www.escholar.manchester.ac.uk/api/datastream?publicationpid=uk-ac-man-scw:212059&datastreamid=full-text.pdf https://www.escholar.manchester.ac.uk/api/datastream?publicationpid=uk-ac-man-scw:212059&datastreamid=full-text.pdf https://www.sciencedirect.com/science/article/pii/s0022024802019383 https://www.sciencedirect.com/science/article/pii/s0022024802019383 https://www.sciencedirect.com/science/article/pii/s0022024802019383 https://www.sciencedirect.com/science/article/pii/s0022024802019383 https://books.google.iq/books?hl=en&lr=&id=gtibcaaaqbaj&oi=fnd&pg=pa1&dq=principles+of+catalysts+development,+plenum&ots=odca4ohteo&sig=kdl3fr14qeospmtjxgbsuz2542k&redir_esc=y#v=onepage&q=principles%20of%20catalysts%20development%2c%20plenum&f=false https://books.google.iq/books?hl=en&lr=&id=gtibcaaaqbaj&oi=fnd&pg=pa1&dq=principles+of+catalysts+development,+plenum&ots=odca4ohteo&sig=kdl3fr14qeospmtjxgbsuz2542k&redir_esc=y#v=onepage&q=principles%20of%20catalysts%20development%2c%20plenum&f=false https://books.google.iq/books?hl=en&lr=&id=hx00aaaaqbaj&oi=fnd&pg=pp1&dq=bioengineered+nanomaterials,+crc+press,+boca+raton&ots=6szvtkjack&sig=rygksl7qhdidx0isybhai5hj6fw&redir_esc=y#v=onepage&q=bioengineered%20nanomaterials%2c%20crc%20press%2c%20boca%20raton&f=false https://books.google.iq/books?hl=en&lr=&id=hx00aaaaqbaj&oi=fnd&pg=pp1&dq=bioengineered+nanomaterials,+crc+press,+boca+raton&ots=6szvtkjack&sig=rygksl7qhdidx0isybhai5hj6fw&redir_esc=y#v=onepage&q=bioengineered%20nanomaterials%2c%20crc%20press%2c%20boca%20raton&f=false https://books.google.iq/books?hl=en&lr=&id=hx00aaaaqbaj&oi=fnd&pg=pp1&dq=bioengineered+nanomaterials,+crc+press,+boca+raton&ots=6szvtkjack&sig=rygksl7qhdidx0isybhai5hj6fw&redir_esc=y#v=onepage&q=bioengineered%20nanomaterials%2c%20crc%20press%2c%20boca%20raton&f=false recovery of heavy metals from aqueous solutions using biosorption 23 ijcpe vol.11 no.3 (september 2010) iraqi journal of chemical and petroleum engineering vol.11 no.3 (september 2010) 23 32 issn: 1997-4884 removal of heavy metals ions from aqueous solutions using biosorption onto bamboo qasim j. m. slaiman**, cecilia kh. haweel * and yossor r. abdulmajeed** chemical engineering department college of engineering nahrain university, iraq ** chemical engineering department, university of baghdad, iraq * ____________________________________________________________________________ abstract feasibility of biosorbent of england bamboo plant origin was tested for removal of priority metal ions such as cu and zn from aqueous solutions in single metal state. batch single metal state experiments were performed to determine the effect of dosage (0.5, 1 and 1.5 g), ph (3, 4, 4.5, 5 and 6), mixing speed (90, 111, 131, 156 and 170 rpm), temperature (20, 25, 30 and 35 °c) and metal ion concentration (10, 50, 70, 90 and 100 mg/l) on the ability of dried biomass to remove metal from solutions which were investigated. dried powder of bamboo removed (for single metal state) about 74 % cu and 69% zn and maximum uptake of cu and zn was 7.39 mg/g and 6.96 mg/g respectively, from 100 mg/l of synthetic metal solution in 120 min. of contact time at ph 4.5 and 25°c with continuous stirring at 170 rpm. experimental results have been analyzed using langmuir and freundlich isotherms. both equilibrium sorption isotherms were found to represent well the measured sorption data, but freundlich isotherm was better than langmuir isotherm. the effect of time was studied and the rate of removal of cu (ii) and zn (ii) ions from aqueous solution by bamboo plant was found. the rates of sorption of copper and zinc were rapid initially within 515 minutes and reached a maximum in about 60 minutes. ________________________________________________________________________________________________ introduction today, the world is facing the problem of water pollution. due to rapid development and industrialization in many countries, the levels of industrial pollution have been steadily rising. the pollution problem of industrial waste water is becoming more and more serious in the world. consequently, the treatment of polluted industrial wastewater remains a topic of global concern since wastewater collected from municipalities, communities and industries must ultimately be returned to receiving waters or to the land. moreover, contamination of ground water is today a iraqi journal of chemical and petroleum engineering university of baghdad college of engineering removal of heavy metal ions from aqueous solutions using biosorption onto bamboo ijcpe vol.11 no.3 (september 2010) 24 major concern in the management of water resources [1]. heavy metals are one of the major pollutants in the environment as a potentially damaging effect on human physiology and other biological systems when the tolerance levels are exceeded. the major sources of heavy metal contamination are considered to be from industry such as zinc from paint, rubber, dye, wood, preservatives and electroplating industries and nickel from paint and powder batteries processing industries. [2] metals are of special concern because they are non-degradable and therefore persistent. the effect of metals in water and wastewater range from beneficial through troublesome to dangerously toxic. zinc causes nausea and vomiting [3] and long term exposure to nickel causes decrease in body weight, heart and liver damage [4]. some metals may be either beneficial or toxic, depending on concentration [5]. therefore, the elimination of heavy metals from water and wastewater is important to protect public health and wild life [6]. the conventional methods used to remove heavy metals include chemical precipitation, ion exchange and electrochemical treatment. [7, 8, 9]. the search for new, effective and economical technologies involving the removal of toxic metals from wastewater has directed attention to biosorption based on metal binding capacities of various biological materials at little or no cost [10]. dead biological materials are capable of removing heavy metal ions from solutions through a process involving a number of diverse mechanisms collectively known as biosorption [11]. biosorption is a process employing a suitable dead biomass to sorb heavy metals from dilute aqueous solutions (1 to 100 ppm) and reduce their concentration to below (1 ppm) [12]. biosorption process removes heavy metal from wastewater without creating hazardous sludge at costs much lower than conventional methods. regeneration of the biosorbent and concentration of the metal solution for eventual recovery further increase the cost effectiveness of the process [13]. a search for a low-cost and easily available biosorbent has led to the investigation of materials of agricultural and biological origin, along with industrial byproducts, as potential metal sorbents [14]. although several studies were available explaining the utilization of several low cost adsorbents, most of these work stand at the laboratory level and only a very few cases have been directly implemented in practical applications at industrial level [15]. agricultural by-products could be heavy metal adsorbents which could be selective for some metal ions. agricultural materials such as banana and orange peels [16] maize cob, coconut husk fibers [17], nut shells [18], soybeans and cotton seed hulls have been evaluated for their adsorptive properties. these materials have been reported to adsorb different pollutants such as heavy metals ions. the research into the utilization of agricultural by-products as adsorbents for the removal of heavy metals from aqueous solutions has been on the increase. this is because these agricultural by-products are naturally occurring; hence they are available at little or no cost. they also have advantage over the conventional adsorbents such as activated carbon particularly because of their low cost and high availability. there is also no need for complicated regeneration processes when using agricultural by – products and they are capable of binding to heavy metals by biosorbtion[19]. . the aim of this work is to characterize a new biosorbent to be used for removal of toxic heavy metals, i.e, cu (ii) and zn(ii) from aqueous solutions. evaluate the single biosorption data in terms of equilibrium isotherms using the langmuir and freundlich adsorption isotherm model. study the effect of different experimental conditions such as ph, biosorbent dose, initial qasim j. m. slaiman**, cecilia kh. haweel * and yossor r. abdulmajeed**. 25 ijcpe vol.11 no.3 (september 2010) metal concentration, temperature and mixing speed on sorption process. sorption isotherm theory different isotherm models have been utilized for describing sorption equilibrium for wastewater treatment. langmuir and freundlich equations are being used for present work. the langmuir sorption isotherm describes the surface as homogeneous assuming that all the sorption sites have equal sorbate affinity and that adsorption at one site does not affect sorption at an adjacent site [20]. the linear form of the langmuir isotherms may be represented as: maxmax 1 q c bqq c e e e  (1) the values of qmax and b can be calculated from the slope and intercept of the plot ce/qe versus ce. the freundlich sorption isotherm (an empirical equation) however, describes the equilibrium on heterogeneous surfaces and does not assume monolayer capacity. the linear form of freundlich sorption isotherm can be represented as [21]: )2(log)/1(loglog efe cnkq  where n and kf are the freundlich isotherm constants. the values of n and kf can be calculated from the slope and intercept of the plot log qe verses log ce. materials and methods preparation of adsorbent (bamboo) the bamboo from united kingdom was collected from guildford in uk, the biomass washed with tap and deionized water, dried and then ground using a food processor and passed through a different size of sieve in order to obtain uniform particle size and washed 2-3 times in deionized water at room temperature then soaking with deionized water several times to remove any contamination in it and after that dried at a temperature 80°c for two days. dried biomass was used for further sorption experiments. preparation of solutions in this experimental works, the biosorption experiments were conducted by using aqueous stock solution (1000 mg l-1) of cu(ii) and zn(ii) which was prepared using salts of cu(so4)2.5h2o and znso4.7h2o. the concentration ranges varied between 10 to 100 mg l-1 with distilled water for single metal and aqueous solution depending on dilution equation. batch sorption experiment using the different amount of biosorbent in a 250ml conical flask containing 100ml of test solution, batch sorption studies were carried out at desired ph value, contact time, temperature,mixing speed, sorbent wieght and sorbate concentration. different initial concentration of cu (ii) and zn (ii) solutions were prepared by proper dilution from stock 1000 mg/l cu(ii) and zn(ii) standard, ph of the solution was monitored by adding 0.1m hcl and 0.1m naoh solution as required. necessary amount of biosorbent was then added and content in the flask were shaken for the desired contact time in an electrically thermostated reciprocating shaker at 170 rpm. the time required for reaching equilibrium condition estimated by drawing samples at regular interval of time till the equilibrium was reached. the content of flask separated from biosorbent by filter and was analyzed for remaining cu (ii) and zn (ii) concentration in the sample. the amount of cu (ii) and zn(ii) sorbed per unit mass of the biosorbent was evaluated by using eq. 4: s ccv q fi )(   (3) removal of heavy metal ions from aqueous solutions using biosorption onto bamboo ijcpe vol.11 no.3 (september 2010) 26 results and discussion effect of ph the most important single parameter influencing the sorption capacity is the ph of the adsorption medium. biosorption capability of waste biomass (bamboo) for cu(ii) and zn(ii) (100 mg/l) in the single metal sorption system at different ph values (3 to 6) is presented in fig. 1 4 4.5 5 5.5 6 6.5 7 7.5 8 0 1 2 3 4 5 6 7ph q ( m g /g ) cu (ii) zn (ii) fig. 1: effect of ph on ions uptake [co=100 mg/l, t=1hr, w=1.0 g/100 ml, mixing speed=170 rpm and temp. =25ºc] it can be noticed from fig. 1 that the uptake of copper increased from 5.75 mg/g at ph=3 to 7.39 mg/g at ph=4.5 and then decreased to 6.83 mg/g at ph=5 but the uptake of zinc increased from 4.65mg/g at ph=3 to 6.88 mg/g at ph=4.5 and then decreased to 6.32 mg/g at ph=6. the adsorption of metal ions depends on solution ph, which influences electrostatic binding of ions to corresponding metal groups. the maximum biosorption of cu (ii) and zn (ii) was observed at ph 4.5. when ph was further increased up to 5 and 6.0 for copper and zinc respectively, the percentage adsorption is decreased. because oh− ions increased the hindrance of diffusion as well as some of the divalent cations may react with oh− ion and precipitated and thereby decreased the free metal ions available in the solution. at lower ph, there may be competition between h+ and metal ions and thus decreased the adsorption capacity of biomass for the metal ion. these results are in close agreement with shafqat et al. [22]. the ph of the metal solution plays a crucial role in biosorption process. as the ph is shifted, the equilibrium will also shift. the best initial ph of cu(ii) and zn(ii) onto waste biomass (bamboo) was observed at ph=4.5. thus, all further experiments were performed at ph=4.5. effect of dosage effect of biosorbents dosage on percentage removal of cu(ii) and zn(ii) was investigated by varying adsorbents dosage in the range of 0.5 g/100 ml to 1.5 g/100 ml and shown in fig. 2. 0 10 20 30 40 50 60 70 80 90 100 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 weight (g) % r e m o v a l cu(ii) zn(ii) fig. 2: effect of biomass (bamboo) dosage on ions percentage removal. [co=100 mg/l, t=1hr, mixing speed=170 rpm, ph=4.5 and temp. =25ºc] from fig. 2, the phenomenon of increase in percentage removal of cu (ii) and zn (ii) with increase in adsorbent dose due to the increased surface area of the biosorbent, which in turn increases the number of binding sites. effect of mixing speed adsorption studies were carried out at varying mixing speeds (90-170) rpm. it was observed that the uptake of adsorption increased with the increase of stirring speed up to 170 rpm as shown in fig. 3. qasim j. m. slaiman**, cecilia kh. haweel * and yossor r. abdulmajeed**. 27 ijcpe vol.11 no.3 (september 2010) 4.5 5 5.5 6 6.5 7 7.5 8 0 20 40 60 80 100 120 140 160 180 m ixing spe e d (rpm) q ( m g /g ) cu(ii) zn(ii) fig. 3: effect of mixing speed on ions uptake [co=100 mg/l, t=1hr, w=1.0 g/100 ml, ph=4.5 and temp. =25ºc]. the increase of adsorption efficiency with the increase of mixing speed could be mainly due to resistance to mass transport in the bulk solution at lower mixing speeds. a thin liquid film surrounding the adsorbent particles offered resistance to mass transport by diffusion. as the mixing speed increased, there would be decrease in the thickness of the boundary film thereby decreasing the effect of film diffusion. effect of metal concentration equilibrium batch adsorption experiments were conducted keeping the dosage of biosorbent constant 1 g of biosorbent biomass per 100 ml of solution and ph=4.5 at different concentrations of metal ions for cu(ii) and zn(ii). fig. 4 shows the effect of metal initial concentration on the equilibrium uptake for biomass. 0 1 2 3 4 5 6 7 8 0 20 40 60 80 100 120 ci (m g m etal ions/l) q e ( m g m e ta l io n s /g b a m b o o ) cu(ii) zn(ii) fig. 4: effect of cu (ii) and zn (ii) initial concentration on the equilibrium uptake for bamboo biomass[mixing speed=170 rpm, t=1hr, w=1.0 g/100 ml, ph=4.5 and temp.=25ºc] it was observed that the uptake capacity increased with the increased in initial metal concentration this is because at higher initial solute concentrations, the ratio of the initial amount of solute to the available surface area is high. adsorption isotherms were used to characterize the interaction of each copper species with the biosorbent. this provides a relationship between the concentration of metal ions (cu (ii) and zn (ii)) in the adsorption medium and the amount of metal ions adsorbed on the solid phase when the two phases are at equilibrium. in order to analyze adsorption isotherms, langmuir and freundlich adsorption isotherms [21] were used to adjust (fit) the experimental data obtained for biosorption of cu (ii) and zn (ii) from copper and zinc solution by bamboo biomass. the adsorption constants (the ultimate sorption capacity (kf) and the sorption intensities (n) in the freundlich model and the maximum uptake capacity (qmax) and the equilibrium constants (b) in the langmuir model) and correlation coefficients obtained from the linearized langmuir and freundlich isotherms are provided in fig. 5 and fig. 6. removal of heavy metal ions from aqueous solutions using biosorption onto bamboo ijcpe vol.11 no.3 (september 2010) 28 y = 0.1139x + 0.6837 r 2 = 0.9425 0 0.5 1 1.5 2 2.5 3 3.5 4 0 5 10 15 20 25 30 ce (mg cu(ii)/l) c e / q e ( g b a m b o o / l ) (a) linearized langmuir equation. y = 0.4899x + 0.1871 r 2 = 0.9991 -0.1 0.1 0.3 0.5 0.7 0.9 1.1 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 log ce l o g q e (b) linearized freundlich equation. 0 1 2 3 4 5 6 7 8 0 5 10 15 20 25 ce (mg cu(ii)/l) q e ( m g c u ( i i ) /g b a m b o o ) experimental isotherm freundlich isotherm langmuir isotherm (c) experimental and adjusted isotherms. fig. 5: equilibrium biosorption isotherms [for co=10-100 mg/l] for cu (ii) ions [mixing speed=170 rpm, t=1hr, w=1.0 g/100 ml, ph=4.5 and temp.=25ºc]. y = 0.1169x + 1.2336 r 2 = 0.9228 0 1 2 3 4 5 6 0 5 10 15 20 25 30 35 ce (mg zn(ii)/l) c e /q ( g b a m b o o /l ) . (a) linearized langmuir equation y = 0.5326x + 0.0244 r 2 = 0.9996 -0.1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 -0.2 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 log ce l o g q e (b) linearized freundlich equation. 0 1 2 3 4 5 6 7 8 0 10 20 30 40 ce (m g zn(ii)/l) q e ( m g z n (i i) /g b a m b o o ) experimental isotherm freundlich isotherm langmuir isotherm (c) experimental and adjusted isotherms. fig. 6: equilibrium biosorption isotherms [for ci=10-100 mg/l] for zn (ii) ions [mixing speed=170 rpm, t=1hr, w=1.0 g/100 ml, ph=4.5 and temp. =25ºc] qasim j. m. slaiman**, cecilia kh. haweel * and yossor r. abdulmajeed**. 29 ijcpe vol.11 no.3 (september 2010) table 1: summary of freundlich and langmuir equilibrium biosorption isotherms results. metal linear freundlich isotherm constants linear langmuir isotherm constants kf 1/n r2 qm ax b r2 cu(ii) 1.5 0.48 9 0.99 9 8.7 0.16 6 0.9 7 zn(ii) 1.1 0.53 2 0.99 9 8.5 0.09 4 0.9 6 the parameters of the two models and the correlation coefficient (r2) for each model was calculated and shown in table 1. results in table 1 show that, the 1/n values are less than 1. this indicates that the isotherms can be characterized well by a convex freundlich isotherm (favorable type) because low values of the sorbate liquid – phase concentration yield large values of the solid-phase concentration. when 1/n values greater than one (concave carve), the isotherm is considered to be unfavorable for sorption because high values of the liquid-phase sorbate concentration are required to get sorption to occur on the sorbent. then the freundlich isotherm parameters 1/n measures the intensity of metal ions on the biomass surface [25]. it is observed from table 1, fig. 5 and fig. 6 that the equilibrium data are well represented by freundlich isotherm equation when compared to langmuir equation. the good fit of freundlich isotherm to an adsorption system means there is almost no limit to the amount adsorbed and there is a multilayer adsorption. although both heavy metals (cu(ii) and zn(ii)) were adsorbed to various extent by the waste biomass (bamboo), the order of adsorption at all concentration was: cu(ii)>zn(ii) (i.e. the sorption rate of cu(ii) is greater than that of zn(ii)). effect of temperature the effect of temperature on the cu (ii) and zn(ii) sorption from aqueous solutions by bamboo was studied by varying the temperature between 20 and 35 °c as shown in fig.7 6 6.5 7 7.5 8 8.5 292 294 296 298 300 302 304 306 308 310 te mp.( k) q ( m g /g ) cu(ii) zn(ii) fig.7: effect of temperature on cu (ii) and zn (ii) uptake [co=100 mg/l, t=1hr, w=1.0 g/100 ml, ph=4.5 and mixing speed=170 rpm] the initial concentration was fixed at 100 mg/l and initial ph was adjusted at 4.5, it can be seen that the uptake increases as the temperature increases. this behavior confirms that the adsorption process is endothermic process. our results are in a good agreement with those obtained for removal of copper ions using dehydrated wheat bran [26]. this is because the attractive forces between biosorbent surface and metal ions are stronger and the sorption increases. this behavior is typical for the adsorption of most metal ions from their solutions onto natural materials. also, it can be noticed that the sorption of metal ions (cu(ii) and zn(ii)) increased slightly with the increase in temperature up to 308 k. this trend of temperature was also observed by qaiser, et al. [27] for cr(vi) biosorption by tree leaves. at high temperature, the diffusion increases, due to the increased tendency of the metal to interact with the biosorbent surface, which results in an increase in sorption as temperature increases. the increase in the adsorption with increasing of temperature removal of heavy metal ions from aqueous solutions using biosorption onto bamboo ijcpe vol.11 no.3 (september 2010) 30 suggests strong adsorption interactions between functional groups of biomass surface and the metal ion, which support the chemosorption. conclusions the biosorption of metal ions named cu (ii) and zn (ii) onto bamboo plant led to the following conclusions: best biosorption of metal ions occurred at ph 4.5. the adsorption of metal ions (cu (ii) and zn (ii)) per unit weight of bamboo decreased as the percent adsorption increased with increasing the adsorbent dosage. the uptake capacity of bamboo increased with the initial metal concentration, temperature and mixing speed increased bamboo has proved to be an efficient for the removal of cu (ii) and zn (ii) ions from aqueous solutions with low concentrations (10-100 mg of metal ion/l) at a laboratory scale. so its utilizing in industrial waste water treatment plants would be convenient to provide economic metal decontamination of large amounts of waste waters of low concentrations waste streams. the single component isotherms for cu (ii) and zn(ii) ions indicated that the biosorption of these metal ions onto bamboo (each one alone) for low range concentration (10-100 mg/l) satisfied the langmuir and freundlich isotherms. but freundlich model represented the data a little better than langmuir one. according to the freundlich isotherm constants, the adsorption of metals was in the order of: cu(ii)>zn(ii). the adsorption uptake capacity for copper larger than the adsorption uptake capacity for zinc for all conditions because the ionic radius for copper smaller than the ionic radius for zinc. acknowledgment we would like to express our sincere thanks and deep gratitude to the to prof. adel o. sharif and dr. sami mohammed for providing the space and all facilities needed in our work in the university of surrey, united kingdom nomenclatures symbol definition units b longmuir equilibrium adsorption constant l /mg c1 concentration of metal ion in stock solution mg/l c2 concentration of metal ion in diluted solution mg/l ce metal ion concentration in solution at equilibrium mg/l ci initial metal ion concentration in solution, mg/l kf freundlich constant related to adsorption capacity (g/l)-1/n n freundlich constant related to intensity q metal uptake mg/g qe metal uptake at equilibrium mg/g qmax maximum metal uptake mg/g r2 square correlation coefficient t absolute temperature k t contact time min. v volume of initial metal ion solution used l v1 volume of stock solution l v2 volume of diluted solution l qasim j. m. slaiman**, cecilia kh. haweel * and yossor r. abdulmajeed**. 31 ijcpe vol.11 no.3 (september 2010) references 1. mohsen, a. h., 2007, "adsorption of lead ions from aqueous solution by okra wastes", international journal of physical sciences, 2(7), pp. 178-184. 2. joshi, n., 2003, "biosorption of heavy metals", m.sc. thesis, department of biotechnology and environmental sciences thapar institute of engineering and technology. 3. atsdr, 2001, "toxicological profile for copper", us dept of health and human services, public health services. 4. cempel, m., and janicka, k., 2002, "distribution of nickel, zinc, and copper in rat organs after oral administration of nickel(ii) chloride", biological trace element research, 90,pp. 215-226. 5. (wpp)water protection program, 2007, "water quality parameters useful in detecting illicit storm water discharges and determining overall stream health, missouri department of natural resources" internet address is www.dnr.mo.gov/env/wpp/index.html 6. eladia, m., méndez, p., havel, j. and patočka, j., 2005, "humic substances compounds of still unknown structure: applications in agriculture, industry, environment, and biomedicine", j. appl. biomed., 3, pp. 13-24. 7. matlock, m.m., howerton, b.s., and atwood, d.a., 2002, “chemical precipitation of heavy metals from acid mine drainage”, water resources, 36(19), pp. 4757 – 4764. 8. feng, d., aldrich, c., and tan, h., 2000, "treatment of acid mine water by use of heavy metal precipitation and ion exchange”, minerals eng., 13(6), pp. 623 – 642. 9. mohammadi, t., moheb, a., sadrzadeh, m., and razmi, a., 2005, “modelling of metal ion removal from waste water by electrodialysis separate”. sep. purificat. technol. 41(1), pp.73 – 82. 10. adesola babarinde, n.a., oyesiku, o.o., j. oyebamiji 1 2 3 babalola and 1janet o. olatunji,2008," isothermal and thermodynamic studies of the biosorption of zinc(ii) ions by calymperes erosum", journal of applied sciences research, 4(6):pp716-721 11. vijayaraghavan, k. and yun, y., 2008, "bacterial biosorbents and biosorption", biotechnology advances, 26, pp. 266–291. 12. wang, j., chen, c., 2009, "biosorbents for heavy metals removal and their future", biotechnology advances, 27, pp. 195– 226. 13. volesky, b. and naja, g., 2007, " biosorption technology: starting up an enterprise", int. j. technology transfer and commercialisation, 6, pp. 196-211. 14. aravindhan, r., madhan, b., raghava, r. j. and unni nair b., 2004, "recovery and reuse of chromium from tannery wastewaters using turbinaria ornata seaweed", j chem technol biotechnol, 79, pp.1251– 1258. 15. abia, a.a., horsfall, jr. m. and didi, o., 2003, "the use of chemically modified and unmodified cassava wastes for the removal of cd, cu and zn ions from aqueous solution", bioresour. technol., 90(3), pp. 345– 348. 16. annadurai, g., juang, rs. and lee, dl., 2002, "adsorption of heavy metals from water using banana and orange peels", water sci. technol., 47(1), pp. 185-190. 17. babarinde, n.a., 2002, "adsorption of zinc (ii) and cadmium (ii) by coconut husk and goat hair", j. pure appl. sci., 5(1), pp. 81-85. 18. demirbas, e., 2003, "adsorption of cobalt (ii) from aqueous solution onto activated carbon prepared from hazelnut shells", adsorpt. sci. technol., 21, pp. 951–963. http://www.dnr.mo.gov/env/wpp/index.html removal of heavy metal ions from aqueous solutions using biosorption onto bamboo ijcpe vol.11 no.3 (september 2010) 32 19. abia, a. a. and igwe, j. c., 2005, "sorption kinetics and intraparticular diffusivities of cd, pb and zn ions on mize cob", african journal of biotechnology, 4(6), pp. 509-512. 20. salehi, p., asghari, b. and mohammadi, f., 2008,"removal of heavy metals from aqueous solutions by cercis siliquastrum l.", j. iran. chem. soc., 5, pp. s80-s86. 21. volesky, b.,2003, "sorption and biosorption", published by bv sorbex, inc. 22. shafcat, f., bhatti, h. n., hanif m. a. and zubair a,, 2008, "kinetic and equilibrium studies of cr(iii) and cr(vi) sorption from aqueous solution using rosa gruss an teplitz (red rose) waste biomass ", j. chil. chem. soc., 53(4), pp. 1667-1672. 23. cordero, b., lodeiro, p., herrero, r. and sastrde m. e., 2004, "biosorption of cadmium by fucus spiralis", environ. chem, 1, 180. 24. nomanbhay, s. and palanisamy, k., 2005, " removal of heavy metal from industrial wastewater using chitosan coatedoil palm shell charcoal ", electronic journal of biotechnology issn: 0717-3458, 8,1, 25. on line at http: // www.ejbiotechnology.info/ content /vol8 /issue1/full/7/ 26. molva, m., 2004, " removal of phenol from industrial wastewaters using lignitic coals", m.sc. thesis, _zmir institute of technology _zmir, turkey 27. özer, a., özer, d. and özer, a., 2004, " the adsorption of copper(ii) ions on to dehydrated wheat bran (dwb): determination of the equilibrium and thermodynamic parameters ", process biochemistry, 39, pp. 2183–2191. 28. qaiser, s., saleemi, a. r. and ahmad, m. m., 2007, "heavy metal uptake by agro based waste materials", electronic journal of biotechnology issn: 0717-3458, vol.10 no.3, issue of july 15, on line at http://www.ejbiotechnology.info/conte nt/vol10/issue3/full/12/ http://www.ejbiotechnology/ http://www.ejbiotechnology.info/content/vol10/issue3/full/12/ http://www.ejbiotechnology.info/content/vol10/issue3/full/12/ 23 iraqi journal of chemical and petroleum engineering vol.11 no.4 (december 2010) 2332 issn: 12010-4884 polyvinyl alcohol/polyvinyl chloride (pva/pvc) hollow fiber composite nanofiltration membranes for water treatment qusay alsalhy 1 , a. figoli 2 , sufyan algebory 1 , ghanim m. alwan 1 , s. simone 2,3 , e. drioli 2,3 1 chemical engineering department, university of technology, alsinaa street no. 52, b.o 35010, baghdad, iraq 2 institute on membrane technology, itm-cnr, c/o university of calabria, via p. bucci cubo 17/c, 87030, rende (cs), italy 3 department of chemical engineering and materials, university of calabria, via p. bucci cubo 42/a, 87030, rende (cs) italy abstract two different polyvinyl alcohol/polyvinyl chloride (pva/pvc) hollow fiber composite nanofiltration membranes were prepared after pvc hollow fiber membranes were coated using dip-coating method with pva aqueous solution, which was composed of pva, fatty alcohol polyoxyethylene ether (aeo9), and water [pva/aeo9/water (4:0.5:95.5) wt%]. effect of two different pvc hollow fiber immersion times in coating solution were studied. cross-section, internal and external surfaces of the pvc hollow fibers and pva/pvc composite nanofiltration membranes structures were characterized by scanning electron microscopy (sem), pure water permeation flux and solutes rejection. it was found that, the coating layer thickness on the outer surface of the 19 wt% pvc hollow fiber was thin and about (6µm), while the coating solution penetrates through the outer edge of the pvc hollow fiber and it looks like sponge-like structure with increase of the dip-coating time from 20 to 30 sec. besides, the pure water permeation flux decreases and solutes rejection increases with an increase of the coating time from 20 to 30 sec for the two pva/pvc composite nanofiltration membranes. iraqi journal of chemical and petroleum engineering university of baghdad college of engineering polyvinyl alcohol/polyvinyl chloride (pva/pvc) hollow fiber composite nanofiltration membranes for water treatment 24 ijcpe vol.11 no.4 (september 2010) molecular weight cut-off (mwco) of the pva/pvc composite nanofiltration membranes were in the range of nf (i.e. 200-3000 mw). keywords: hollow fiber composite membrane; nanofiltration; polyvinyl chloride; polyvinyl alcohol; morphology; separation performance. introduction the development of nanofiltration technology in separation processes is being widely studied because of its advantages, such as low operation pressure, high flux, high retention of multivalent anion salts and organic molecules above 300 mw. therefore, it has given rise to worldwide interest [1]. most nanofiltration (nf) membranes developed to date are composite membranes, with a selective layer on top of the micro-porous substrate. the choice of membrane materials depends on both chemical and physical compatibility of the selective layer with the substrate, which in turn determines the stability and performance of the resulting composite membranes. several researchers studied different methods for the preparation of composite nf membranes, for example, vapor deposition, plasma initiated polymerization, photo initiated polymerization, the dip coating method, electron beam irradiation, atom transfer radical polymerization, resin-filled chelating, in situ amines cross-linking, and vacuum coating process [2-10]. several studies were done on the preparation of the composite nf membrane by coating methods, for example, nela [11] has studied the preparation and characterization of composite nanofiltration membranes consisting of poly (acrylonitrile) (pan) ultrafiltration support membrane and polydimethylsiloxane (pdms) as the selective top layer. influence of the coating solution concentration upon the membrane performance and the contact time of the membrane with coating solution in dip-coating method were investigated. tao he [12] studied the preparation and characterization of nanofiltration membrane based on coating of a sulfonated poly (ether ether keton) (speek) layer on top of a polyethersulfone or polysulfone support for ion separation and removal. it was found that the rejection can be improved by an increase in the coating thickness, polymer concentration in the coating solution and the pore size of support membrane. besides, n, ocarboxymethyl chitosan (nocc) composite nanofiltration membranes has been prepared using coating and crosslinking method by miao et al. [13]. iraq suffers from lack of water in addition to the high salinity in the rivers of tigris and euphrates and among the proposals and recommendations for solving this problem is to build systems for water desalination. this leads to the challenge of the fabrication of the hollow fiber nanofiltration membranes for the purpose of the water desalination of iraqi rivers. in this effort, polyvinyl alcohol/polyvinyl chloride (pva/pvc) hollow fiber composite nanofiltration membranes were prepared after pvc hollow fiber membranes were coated using dip-coating method with pva aqueous solution, which were composed of pva, fatty alcohol polyoxyethylene ether (aeo9), and water. pva/pvc qusay alsalhy1, a. figoli2, sufyan algebory1, ghanim m. alwan1, s. simone2,3, e. drioli2,3 25 ijcpe vol.11 no.4 (september 2010) composite nanofiltration membranes structures were characterized by scanning electron microscopy (sem). in the present study, nanofiltration tests were conducted using different solutes of different molecular weights, polyethylene glycol, peg; and na2so4. materials poly vinyl alcohol pva (75,00079,000 da) in powder form and fatty alcohol polyoxyethylene ether (aeo9) were obtained from sigma–aldrich chemical company, used as coating materials. the hollow fiber membrane was poly (vinyl chloride) used as supported membrane. pvc hollow fiber membranes were prepared in laboratory in previous work and all specifications were summarized in table 1 [14]. na2so4 and polyethylene glycol (peg 600mw) were used as solutes and obtained from chem.-supply, s. australia and searle company, england, respectively. table 1 characteristics of the pvc hollow fiber membranes prepared in previous work [14]. preparation of the pva/pvc composite nf membranes and posttreatment for the preparation of the coating solution, pva/water/aeo9 (4:95.5:0.5) (concentrations in wt.%) solutions were prepared as follow: pva was dissolved in water at 90°c with agitation to become pva aqueous solution. after cooling the pva aqueous solution to room temperature, aeo9 was mixed with the pva solution, which was supposed to decrease the solution interfacial tension with pvc hollow fiber surface until the coating solution became homogeneous. finally, pvc hollow fiber membranes were coated by dip-coating method, where the hollow fibers were immersed in the coating solution for 20 and 30 seconds. the pva-coated pvc hollow fiber composite membranes were then dried at room temperature. the final pva/pvc hollow fiber composite nanofiltration membranes were obtained after heat treatment in an oven at 70 ºc for two hours. sem observations the membrane’s morphology was observed by using scanning electron microscope (cambridge stereoscan 360). fibers cross sections were prepared by freeze fracturing the samples in liquid nitrogen, to produce a clean brittle fracture. the internal and external surfaces were also observed. measurements of permeation flux and solute rejection three pieces of hollow fibers were sealed into stainless steel tube with two stainless steel tees to make the lab-scale modules with 20 cm effective length and 0.5 cm inner diameter. these modules were left overnight for curing before testing in terms of permeation flux and solute rejection. each module was immersed in distilled water for 24 hours, and run in the test system for one and half hours before any sample collection. fig. (1) shows a schematic diagram of solute–water separation unit. at a membrane type i.d. (mm) o.d. (mm) thickness (mm) porosity (ε%) mean pore size (µm) pvc 17% 0.680 0.830 0.075 55.81 0.12 pvc 19% 0.720 0.955 0.117 55.60 0.15 polyvinyl alcohol/polyvinyl chloride (pva/pvc) hollow fiber composite nanofiltration membranes for water treatment 26 ijcpe vol.11 no.4 (september 2010) transmembrane pressure 1 bar and feed solution temperature 25 ºc, all experiments were performed in hollow fiber modules. three modules were prepared for each hollow fiber sample. pure water permeation fluxes (pwp), were obtained as follows: s w w ap q j   (4) where jw is the permeation flux of membrane (l/(m 2 .h.bar)), qw is the volumetric flow rate (l/h), δp is the transmembrane pressure drop (bar), and as is the membrane surface area (m 2 ). na2so4 and peg 600da with 1000 ppm were used for the measurement of solute rejection of each hollow fiber module, respectively. the membrane rejection r (%) is defined as:  % 1 100% p f c r c           (5) where f c and p c are the solute concentration in feed and permeate solution respectively. the concentration of na2so4 was determined based on conductivity meter (model dds-307). while the concentration of peg 600mw in feed and permeate streams were determined by using dragendorff reagent. 5 ml of peg solution were kept in 10 ml volumetric flask and mixed with 3 ml of 0.05 m hcl, then 1 ml of dragendorff reagent was added and the volume of the mixture was completed with 0.05 m hcl. after at least 15 minutes, the solution concentration was measured based on its absorbency with uv-spectrophotometer (cary-australia) at 510 nm [15]. fig. 1 schematic diagram of the nf experimental set-up. resaluts and discussion pva/pvc hollow fiber composite nf membranes have been prepared by deposition of pva selective layer on pvc hollow fiber membranes using dipcoating method. polyvinyl alcohol (pva) is one of the strong hydrophilic materials that is suitable for the separation of aqueous mixture [16]. two different pvc hollow fiber membranes were prepared in previous work used as a supported membrane for the preparation of nf composite membrane and the characteristics of the pvc hollow fiber membranes are summarized in table 1 [14]. figures 2-5 show the sem cross-section and external surfaces images for the two hollow fiber membranes prepared from 19 and 17 wt% pvc before and after coating, respectively. it can be seen that two small finger-like structure layers are situated at both edges of the hollow fiber qusay alsalhy1, a. figoli2, sufyan algebory1, ghanim m. alwan1, s. simone2,3, e. drioli2,3 27 ijcpe vol.11 no.4 (september 2010) and the layer has large macrovoids in the shape of finger-like structure and there is a sponge-like structure situated between the large macrovoids structure and the outer finger-like in figure 2a. figure 2b shows the effect of 20 seconds dipcoating time of the pvc membrane in pva / aeo9 / water (4:0.5:95.5) (concentrations in wt.%) solution on the outer surface of the membrane. it can be seen that the coating layer thickness on the outer hollow fiber surface was thin and about (6µm), while the coating solution penetrates through the outer edge of the pvc hollow fiber and it looks like sponge-like structure with increase of the dip-coating time to 30 seconds as shown in figure 2c. yangishita et al. [5], observed that the composite membranes after coating by 1 wt% poly(amic acid)tri-ethylamine salt (paa salt) methanol solution did not show finger-like structure because the coating solution penetrated into the supporting membrane, and filled up in the finger-like structure. in figure 3, the porous external surface was changed to dense and rough surface (no pores) after coating with 20 and 30 sec. figure 2 sem cross-section images for the hollow fiber membranes prepared from 19 wt% pvc, (a) without coating, (b) coating time is 20 sec (c) coating time is 30 sec. a b c polyvinyl alcohol/polyvinyl chloride (pva/pvc) hollow fiber composite nanofiltration membranes for water treatment 28 ijcpe vol.11 no.4 (september 2010) figure 3 sem external surface images for the hollow fiber membranes prepared from 19 wt% pvc, (a) without coating, (b) coating time is 20 sec (c) coating time is 30 sec. from the cross-section sem images of the hollow fiber membrane prepared from 17 wt% pvc and after dip-coating with pva/water/aeo9 (4:95.5:0.5) (concentrations in wt.%) solution it can be seen that there is a distinct coating layer over porous support layer without pore intrusion as shown in figures 4. this might be explained as the external skin layer having small pore size which is sealed by coating solution; consequently, the thickness of skin layer has been increased. in agreement, jansen et al. [17], has explained that the average pore size, and thus the molecular weight cut-off of the membranes was sufficiently small to avoid penetration of the polymer molecules in the pores, so that a b c figure 4 sem cross-section image of the hollow fiber membrane prepared from 17 wt% pvc with 20 seconds coating time. qusay alsalhy1, a. figoli2, sufyan algebory1, ghanim m. alwan1, s. simone2,3, e. drioli2,3 29 ijcpe vol.11 no.4 (september 2010) figure 5 sem external surface images for the hollow fiber membranes prepared from 17 wt% pvc, (a) without coating, (b) coating time is 20 sec (c) coating time is 30 sec. only a thin film of the polymer is formed on the support surface. the increasing of skin layer thickness has more influence on decreasing permeate flow and in the same time will ameliorate the retention function of the membrane. on the other hand, there are no distinct surface pores indicating that pore size has been largely decreased as shown in figure 5. the surface defects shown in figure 5b and 5c probably due to the shrinkage of the film during the evaporation of the last traces of the solvent from the film, this phenomenon which is also observed in membranes prepared by jansen et al. [17]. table 2 shows effect of coating time on the pva/pvc composite hollow fiber nanofiltration membranes performance. it can be observed that the permeation flux of all hollow fiber nanofiltration membranes have largely decreased compared with those bare fibers. moreover, the permeation flux decrease and solutes rejection increased with an increase of coating time. for hollow fiber nf membrane prepared from 17% pvc, the permeation flux has declined by 61% with 20 seconds coating time compare to bare fiber and further decreased when coating time is increased to 30 seconds. on the other hand, the peg 600da rejection significantly increased with coating time. these results imply that the coating layer thickness increased with coating time. nela [11] found that the thickness of top layer was increased with increasing of the contact time with coating solution. b c a polyvinyl alcohol/polyvinyl chloride (pva/pvc) hollow fiber composite nanofiltration membranes for water treatment 30 ijcpe vol.11 no.4 (september 2010) table 2 pva / pvc composite hollow fibre nanofiltration membranes performance *: not measured. 1: pure water permeability in lm -2 .hr -1 .bar -1 in the case of hollow fiber nf membranes prepared from 19% pvc, the permeation flux decreased by 9395% compared to that obtained from uncoated hollow fibers, while the solutes rejection increased when the coating time was increased from 20 to 30 seconds. from figure 2 the finger-like structure beneath the outer skin layer was filled up with coating solution, thus there was much reduction in permeation flux and this is attributed to the higher resistance through the support membrane. according to the results mentioned above, hollow fiber nf composite membranes have a good nf characteristic membrane with permeation flux in the range of nf membranes (i.e. 5-15 l.m -2 .hr -1 .bar -1 ), and 60% solute rejection for peg 600mw suggests that mwco would be in the range of nf (i.e. 200-3000 da). conclusions pva/pvc hollow fiber composite membranes were prepared for aqueous nanofiltration separation systems, using dip-coating method. the effects of coating time on the structural morphology and performance of the resulted membranes were studied. the structure and performance of the membranes were characterized by scanning electron microscope (sem), permeation flux and solutes rejection. it was found that the permeation flux of the prepared nf composite membranes highly decreased with coating time on the base membranes with increase of the solute rejection. besides, the coating layer thickness on the outer hollow fiber surface was thin and about (6µm), while the coated solution penetrates through the outer edge of the pvc hollow fiber and it looks like sponge-like structure with increasing dip-coating time to 30 seconds. the molecular weight cut-off of the prepared hollow fiber nf composite membranes was 1000 da. acknowledgments associate prof. dr. qusay f. alsalhy gratefully thanks the institute on membrane technology, itm-cnr, and department of chemical engineering and materials, university of calabria, rende, italy, for the scanning electron microscope (sem) and mean pore size measurements. references [1] yongqiang yang, xigao jian, daling yang, shouhai zhang, longjiang zou,(2006),” poly(phthalazinone ether sulfone ketone) (ppesk) hollow fiber asymmetric nanofiltration membranes: preparation, morphologies and properties”, j. membr. sci. 270 , 1–12. mem brane type coatin g time (sec) pwp 1 before coatin g pwp 1 after coatin g na2so4 rejecti on (r %) peg600 rejection (r %) pvc 17% 20 66.5 25.3 6.42 1 pvc 17% 30 66.5 8.2 nm * 60.3 pvc 19% 20 129 9.0 10.5 13 pvc 19% 30 129 5.9 6.5 49 qusay alsalhy1, a. figoli2, sufyan algebory1, ghanim m. alwan1, s. simone2,3, e. drioli2,3 31 ijcpe vol.11 no.4 (september 2010) [2] h. yanagishita, d. kitamoto, k. haraya, t. nakane, t. tsuchiya, n. koura,(1997),” preparation and pervaporation performance of polyimide composite membrane by vapor deposition and polymerization (vdp)”, j. membr. sci. 136 ,121–126. [3] t. yamaguchi, s. nakao, s. kimura,(1991), ” plasma-graft filling polymerization: preparation of a new type of pervaporation membrane for organic liquid mixture”, macromolecules, 24,5522–5527. [4] m. ulbricht, hans-hartmut schwarz,(1997),” novel high performance photograft composite membranes for separation of organic liquids by pervaporation, j. membr. sci. 136, 25–33. [5] yangishita h., kitamato d., haraya k., nakone t., okada t., matsuda h., idemoto y., koura n.,(2001),” separation performance of polyimide composite membrane prepared by dip coating process”, j. membr. sci., 188, 165-172. [6] h. yanagishita, j. arai, t. sandoh, h. negishi, d. kitamoto, t. ikegami, k. haraya, y. idemoto, n. koura,(2004),” preparation of polyimide composite membranes grafted by electron beam irradiation”, j. membr. sci. 232, 93–98. [7] anagi m. balachandra, gregory l. baker1, et al.,(2003),” preparation of composite membranes by atom transfer radical polymerization initiated from a porous support”, j. membr. sci. 227,1– 14. [8] guangling pei, guoxiang chenga, qiyun du, (2002),” preparation of chelating resin filled composite membranes, and selective adsorption of cu(ii)”, j. membr. sci. 196, 85-93. [9] xu tongwen, yang weihua,(2003),” a novel positively charged composite membranes for nanofiltration prepared from poly(2,6-dimethyl-1,4phenylene oxide) by in situ amines cross-linking”, j. membr. sci. 215, 25–32. [10] y. m. wei, z. l. xu, a. f. qusay,(2005),” ethanol-water mixture separation by pervaporation process using (pva/psf) hollow fiber composite membranes”, j. appl. polym. sci., vol. 98, 247-254. [11] stafie nela,(2004),” poly (dimethyl diloxane)-based composite nanofiltration membranes for non-aqueous application”, university of twente, the netherlands: phd thesis. [12] he t.,(2001),”composite hollow fiber membranes for ion separation and removal”, university of twente, the netherlands: ph.d. thesis. [13] jing m., lingling l., guohua c., congjie g., shengxiong d.,(2008),” preparation of n, o-carboxymethyl chitosan (nocc) composite nanofiltration membranes and its rejection performance for the fermentation effluent from a wine factory”, chin. j. chem. eng., 16, 209213. [14] qusay alsalhy, sufyan algebory, ghanim m. alwan, s. simone, a. figoli, e. drioli,(2010),” ultrafiltration hollow fiber membranes from poly(vinyl chloride): preparation, morphologies and properties”, submitted to separation science and technology . [15] z. jia, tian c.,(2009),” quantitative determination of polyethylene glycol with modified dragendorff reagent method”, desalination, 247 (2009) 423429. [16] yong-ming wei, zhen-liang xu, f. alsalhy qusay, kai wu,(2005),” polyvinyl alcohol/polysulfone (pva/psf) hollow fiber composite membranes for pervaporation separation of ethanol/water solution”, j. appl. polym. sci., 98, 247–254. polyvinyl alcohol/polyvinyl chloride (pva/pvc) hollow fiber composite nanofiltration membranes for water treatment 32 ijcpe vol.11 no.4 (september 2010) [17] jansen j. c., tasselli f., tocci e., drioli e.,(2006),” high flux composite perfluorinated gas separation membranes of hyflon ad on hollow fiber ultrafiltration membrane support”, desalination, 192, 207-213. الخالصة بىاسطت طشيقت االكسبء ببنتغطيس pva/pvc تى تحضيش َىعيٍ يٍ اغشيت االنيبف انًجىفت وانُبَىيت انًكىَت يٍ fatty alcohol (aeo9)انًبء و, pva انًبئي انًكىٌ يٍ بىني فُيم انكحىل pva في يحهىل polyoxyethylene etherعهً انتىاني(4 ,95.5 ,0.5) وبُسب وصَيت يئىيت . انيبف تى دساست تبثيش وقتيٍ يختهفيٍ نضيٍ اكسبء اغشيت االنيبف انًجىفت عهً انتشكيب انذاخهي وانخبسجي الغشيت pva/pvc انًشكبت وانُبَىيت ببستخذاو جهبص انًجهش االنكتشوَي انًبسح (sem) وايضب عهً اداء االغشيت في كبٌ سقيقب وبسًك pvc %19وجذ اٌ سًك طبقت االكسبء نالنيبف انًحضشة يٍ. فصم انًزاببث واَتبج انًبء انُقي µm6 بيًُب يذخم يحهىل االكسبء خالل انسطح انخبسجي ويسذ انتشاكيب االصبعيت انشكم عُذيب يضداد صيٍ االكسبء 30-20تقم َفبريت انًبء انُقي ويضداد فصم انًزاببث بضيبدة صيٍ االكسبء يٍ , ببالضبفت انً رنك. ثبَيت30-20يٍ الغشيت (mwco)اٌ انىصٌ انجضيئي نهًزاببث انًفصىنت. ثبَيت نكال َىعي االنيبف انًجىفت انُبَىيت (. 3000da -200) انًجىفت انُبَىيت كبٌ ضًٍ يذي اغشيت انفصم انُبَىيت pva/pvcانيبف ijcpe vol.10 no.2 (june 2009) iraqi journal of chemical and petroleum engineering vol.10 no.2 (june 2009) 35-42 issn: 1997-4884 extraction of iron from aqueous chloride media in presence of aluminum dr. wadood t. mohammed * and alyaa kh. mageed * chemical engineering department college of engineering university of baghdad – iraq abstract the extraction of iron from aqueous chloride media in presence of aluminum was studied at different kinds of extractants(cyclohexanone, tributyl phosphate, diethyl ketone), different values of normality (ph of the feed solution), agitation time, agitation speed, operating temperature, phase ratio (o/a), iron concentration in the feed, and extractant concentration]. the stripping of iron from organic solutions was also studied at different values of normality (ph of the strip solution) and phase ratio (a/o). atomic absorption spectrophotometer was used to measure the concentration of iron and aluminum in the aqueous phase throughout the experiments.the best values of extraction coef ficient and stripping coefficient are obtained under the conditions of operation given in the table below: system operation ph agitation time (min.) agitation speed (rpm) temperature o c phase ratio cyclohexanone conc. cyclohexanone exraction 1.5 10 400 30 3/1 50% stripping 1 10 400 30 3/1 50% introduction iron extraction iron now is being removed from solutions in afew plants; the major reason for its elimination is only to remove it from the system so that the recovery of the major value metal may be facilitated in the subsequent operations. al-hemiri and wadood (1) studied the extraction of iron from aqueous chloride media by cyclohexane and methyl iso-butyle ketone with different operating conditions. their results showed that, the extraction coefficient increases with increasing extractant concentration. and decreases with increasing iron concentration in feed.the best values of extraction coefficient and stripping coefficient are obtained under the conditions of operating given in table below; system operating temp.c 0 agitation time(min.) agitation speed(r.p.m) phase ratio normality cyclohexanone extraction 25 10 300 3/1 4 stripping 40 10 300 1/2 0.5 mibk extraction 25 5 300 3/1 4 stripping 35 20 300 1/1 0.5 university of baghdad college of engineering iraqi journal of chemical and petroleum engineering ijcpe vol.10 no.2 (june 2009) reddy and saji (2), presented a paper reported on the investigations carried out to recover high purity iron (ш), titanium (іv) and vanadium (v) from titania waste chloride liquors, based on their value and concentrations, in two stages solvent extraction process employing commercially available extractants. the first stage clearly shows that high purity iron (ш) chloride can be selectivity separated from a multivalent metal chloride feed consist of: fecl3, tiocl2, mgcl2, alcl3, vocl3, crcl3, and hcl by employing a tbp-mlbk mixed-solvent extraction system. in the second stage, 2ethyl hexyl phosphoric acidmono-2-ethyl hexyl ester [ehehpa] in kerosene is used as an extractant to recover titanium (іv) and vanadium (v). this study clearly showed that high purity iron (iii) chloride (purity 99.9%) could be selectively separated from a multivalent metal chloride feed. arifien et al. (3), studied the extraction of fe(iii) ,co(ii), ni(п) and cu(п) from aqueous media with thiourea monophosphazene (h2mpz)[little information are available in using this compound as chelating and extracting agent] in chloroform at three degrees of temperature (20,25,and 30oc). it was found that the temperature has no effected on the stoichiometry of the extracted species. the use of n,n′-tetrasubstituted malonamides such as n,n′-dimethyl-n,n′-diphenylmalonamide (dmdphma) and n,n′-dimethyl-n,n′-diphenyltetradecylmalonamide (dmdphtdma) for the extraction of iron(iii) from acid chloride solutions was investigated by costa et al.(4), in order to evaluate the possibility of using this family of compounds to extract base metal cations. in this investigation, a mechanism for iron(iii) extraction from chloride media by dmdphma and dmdphtdma is proposed, a comparison between their extraction behavior and involved mechanisms for both chloride and nitrate media being considered as well. the results suggested that dmdphma and dmdphtdma extract iron(iii) through different mechanisms, thus showing the influence of the chemical structure on the metal ion transfer reactions to the organic phase. for dmdphma, an anionic-pair mechanism involving iron(iii) extraction as the chlorocomplex fecl4− seems to occur, while for dmdphtdma a solvation mechanism appears to be the predominant one. the extraction of magnesium(ii), aluminum(iii), titanium(iv), vanadium(v), chromium(iii), manganese(ii), and iron(iii) from hydrochloric acid solutions (0.01–2.0 mol dm-3) using various 3-phenyl-4acyl-5-isoxazolones, namely, 3-phenyl-4-(4fluorobenzoyl)-5-isoxazolone (hfbpi), 3-phenyl-4benzoyl-5-isoxazolone (hpbi), and 3-phenyl-4-(4toluoyl)-5-isoxazolone (htpi) was investigated by remya et al. (5). iron stripping stripping is the reverse process to extraction where problems can occur when the stability of the extracted complex is so great that even concentration acids will not allow the metal to be stripped. the stability of the extracted species will govern the type and concentration of strip solution required(6). stripping of vanadium(v) and titanium(iv) after selective recovery of iron(iii) was studied by reddy and saji (2), vanadium(v) from the loaded organic phase was selectively stripped by using (0.5 mol.dm-3) h2so4 as a stripping agent in three stages leaving behind titanium(iv) in the organic phase. subsenquently, titanium (iv) was recovered from the loaded organic phase using a mixture consisting of (2 mol.dm-3) h2so4 and (2%) h2o2 as a stripping agent in two stages. costa et al. (4), investigated the stripping of iron(iii) from the loaded organic phases by a simple contact with water, and the selectivity towards iron(iii) presented by both malonamide derivatives when several base metal cations co-exist in the acid chloride aqueous solutions can be considered very promising. in this study, we attempt to extract the iron from aqueous chloride media in presence of aluminum (12). experimental work experimentation chemicals the following substances are used for carrying out the experiments: 1. hydrochloric acid. 5. cyclohexanone. 2. ferric chloride. 6. tributyl phosphate 3. aluminum chloride. 7. diethyl ketone 4. benzene. ijcpe vol.10 no.2 (june 2009) equipment: the equipments used were: 1. water bath equipped with temperature controller (baird and tatlock ,unitemp water bath). 2. electrical mixer with a two blade glass impeller (janke and kunkle , ika-werk) 3. atomic absorption spectrophotometer (aa670, shimadzu corporation, japan ) 4. glass ware (round bottom). 5. separating funnel. the operation steps are shown in fig. (1) fig. (1) operation steps experimental extraction operation extractants selectivity: in this set of experiments, the effect of selectivity of the extractant on the extraction coefficient was investigated. the aqueous phase was prepared by dissolving fecl3 and alcl3 in hcl acid solution to reach the concentration of iron and aluminum of about (4g/l) for each metal. the organic phase used was (cyclohexanone, diethyl ether, tributyl phosphate, diethyl ketone). a volume of the aqueous phase mixed with the specified volume of the organic phase according to the phase ratio. the other variables (ph=1.5, agitation time=10 min., agitation speed=400 rpm, operating temp. =30oc, iron conc. =4g/l, aluminum conc. =4g/l and phase ratio=3/1) being kept constants. a sample of the raffinate was measured in petrochemicals company – basrah by using the atomic absorption spectrophotometer (aa-670, shimadzu corporation, japan) for the iron and aluminum concentration. phase aqueousin metal ofion concentrat phase organicin metal ofion concentrat e phase aqueousin metal of conc. initial aqueouin metal of conc. final phase aqueousin metal of conc. initial removed metal %  lead removal from industrial wastewater by electrocoagulation process 2 ijcpe vol.10 no.2 (june 2009) effect of ph of the feed solution in this set of experiments, the effect of ph of the aqueous solution on the extraction coefficient was investigated. varied values of ph of the feed solution, which were (1, 1.5, 2, 2.5,3 and 3.5). the organic phase achieved from the previous section and diluted with benzene to 50% vol. /vol. the other variables (agitation time=10 min., agitation speed=400 rpm, operating temp. =30oc, iron conc. =4g/l, aluminum conc. =4 g/l and phase ratio=3/1) being kept constants. a sample of the solution was taken at the end of each period (3, 5, 10, 15 and 20 min.) to determine the iron and aluminum concentrations. effect of agitation time in this set of experiments, the effect of agitation time was investigated. the extractant and ph value of the feed were achieved from the previous sections and other variables (agitation speed=400 rpm, operating temp.=30oc, iron conc.=4g/l, aluminum conc.=4g/l and phase ratio=3/1 ) being kept constants. effect of agitation speed in this set of experiments, the effect of agitation speed was investigated. a sample of the solution was taken at the end of each run of different speeds (200,300,400 and 500 rpm) to determine the iron and aluminum concentration. the variables (operating temp.=30oc, iron conc.=4g/l, aluminum conc.=4g/l and phase ratio=3/1 ) being kept constants. the extractant, ph value of the feed and agitation time were achieved from the previous sections. effect of temperature in this set of experiments, the effect of temperature was investigated. i.e (30, 35, 40, 45 and 50oc) to determine the iron and aluminum concentration. the extractant, ph value of the feed, agitation time and agitation speed were achieved from the previous sections. and the other variables (iron conc.=4g/l, aluminum conc.=4g/l and phase ratio=3/1) being kept constants. effect of phase ratio (o/a) the effect of phase ratio on the extraction coefficient was investigated in this set of experiments. the phase ratios (o/a) used were (1/1, 2/1, 3/1 and 4/1). the other variables (iron conc.=4g/l, and aluminum conc.=4g/l ) being kept constants. the extractant, ph value of the feed, agitation time, agitation speed and operating temp. were achieved from the previous sections. the aqueous phase mixed with the specified amount of the organic phase according to the ratio. effect of iron concentration in this set of experiments, the effect of initial iron concentration on the extraction coefficient is studied. the extractant, ph value of the feed, agitation time, agitation speed, operating temp. and phase ratio were achieved from the previous sections and aluminum conc.=4g/l being kept constant. effect of cyclohexanone concentration the effect of extractant concentration on the extraction coefficient was studied in this set of experiments. the ranges of the concentration of the extractant used is (25, 50, 75, and 100 % vol. /vol.). the extractant, ph value of the feed, agitation time, agitation speed, operating temp. phase ratio and iron conc. were achieved from the previous sections and aluminum conc.=4g/l being kept constant. stripping operation from the previous studies, the following values are fixed (agitation time =10 min., agitation speed =400 r.p.m., temp.=30 oc). effect of ph of the strip solution the effect of ph of the strip solution on the stripping coefficient was studied in this set of runs. the ph varied (0, 1, 1.5,2 and 2.5). the organic phase (loaded solvent) used was prepared from the extract of extraction stage. the other variable (phase ratio=3/1) being kept constant. effect of phase ratio (a/o) in this set of experiments, the effect of phase ratio (a/o) on the stripping coefficient was investigated. the organic phase (loaded solvent) used was prepared as in the previous set, ph value of the strip solution was achieved from the previous section. the phase ratio (a/o) used in this set varied (1/1, 2/1, 3/1, and 4/1). results and discussion extraction operation effect of selectivity the results obtained from this set are listed in table (1), showing that using (cyclohexanone) as an extractant gave the highest value of extraction coefficient. cyclohexanone has good kinetic of extraction, the axial overlap of the two (sp3) atomic orbitals from a strong  bond between them. the carbon-carbon bond length in saturated compounds is found to be pretty constant (0.154 nm (1.54 a)). this refers, however to a carbon-carbon ibtehal k. shakir and besma i. husein 3 ijcpe vol.10 no.2 (june 2009) single bond between (sp3) hybridized carbons. for two carbon atoms bonded to each other the nuclei are drawn inexorably closer together on going from sp3-sp3 sp2-sp2  sp1-sp1 the rigidity that take place because of the formation of the ring (7). table 1 the result of extractants selectivity extractants percentage removal fe. al. * cyclohexanone 90.2 6.9 126.814 tributyl phosphate 82 12 33.4094 diethyl ketone 75 10 27.0004 aqueousin alfraction wt aqueousin fefraction wt solventin alfraction wt solventin fefraction wt  effect of ph of the feed solution the results as shown in figs. (2 and 3) indicate that increasing the ph lead to an increase in the extraction coefficient up to a limit then decrease. thus, ph=1.5 gave the highest value of extraction coefficient. however the general effect of increasing the ph is as shown in the figs., where the recovery increase with increasing ph values then levels off and finally decreases. the decrease in recovery is due to hydrolysis of the metal (6). fig. (2) extraction coefficient vs. ph, at (t=10 min., speed=400 rpm, t=30oc, r=3/1, fe conc.=4g/l, and al conc.=4g/l) fig. (3) percentage removal vs. ph, at (t=10 min., speed=400 rpm, t=30oc, r=3/1, fe conc.=4g/l, and al conc.=4g/l) effect of agitation time the results clearly demonstrated that using an agitation time of (10min.) gave the highest extraction coefficient and percentage of iron removal as shown in figs. (4 and 5). the solvent extraction is an equilibrium process, it found that the equilibrium is completed at (10 min.) of contact time and the increasing in the agitation time has no influence on the loading of the organic phase. similar results were obtained by al-hemiri and wadood(1), in the extraction of iron from aqueous chloride solutions by cyclohexane and mibk. effect of agitation speed the results, as shown in figs. (6 and 7), indicate that the agitation speed of (400 rpm) gave the highest values of extraction coefficient and percentage of iron removal. the surface area of the dispersed phase will depend on the amount of the agitation speed. however, it should not be thought that the greater the agitation speed the greater the rate of metal extraction. too much agitation speed can result in the formation of a solute or semi-stable emulations. furthermore, decreasing the drop size of dispersed phase can result in making the drop resemble rigid spheres. in this condition there is no internal movement with in the spheres, no new surfaces are produced, and the extractant with in the sphere cannot get to the surface to reach with metal ions. consequently, the extraction rate is slow (8). ph p e r c e n ta g e r e m o v a l 0 20 40 60 80 0.8 1.4 2.0 2.6 3.2 3.8 fe al lead removal from industrial wastewater by electrocoagulation process 4 ijcpe vol.10 no.2 (june 2009) fig. (4) extraction coefficient vs. agitation time, at (ph=1.5, speed=400 rpm, t=30oc, r=3/1, fe conc.=4g/l, and al conc.=4g/l) fig. (5) percentage removal vs. agitation time, at (ph=1.5, speed=400 rpm, t=30oc, r=3/1, fe conc.=4g/l, and al conc.=4g/l) fig. (6) extraction coefficient vs. agitation speed, at (ph=1.5, t=10 min., t=30oc, r=3/1, fe conc.=4g/l, and al conc.=4g/l) fig. (7) percentage removal vs. agitation speed, at (ph=1.5, t=10 min., t=30oc, r=3/1, fe conc.=4g/l, and al conc.=4g/l) effect of operating temperature the results plotted in figs. (8 and 9) indicate that increasing the temperature lead to an increase in the extraction coefficient and percentage of iron removal. arifien et al. (3), obtained the similar results in the extraction of fe (ш), co (п), ni (п) and cu (п) with thiourea monophosphazene. effect of phase ratio (o/a) as indicated in fig.(10), that increasing the phase ratio (o/a) cause a significant increase in the extraction coefficient and the phase ratio of (3/1) gave the highest value for the system. this might be attributed to the increase in the quantity of transferred metal which is related with quantity of extraction that will furnish the necessary molecules to form the complex to reach the equilibrium state. the behavior is valid to an extent beyond it the extraction coefficient will decrease, because the quantity or volume of the organic phase increases, the amount of metal transferred will undergo somewhat smaller increase leading to a decrease in the concentration of metal, hence causing a decrease in the extraction coefficient(8). fig. (11) further support the above conclusion where this figure represents the percentage removal of iron and aluminum, the percentage of iron removal increases up to a limit then it remains nearly constant. agitation time (min.) e x t r a c t io n c o e f f ic ie n t 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 0 4 8 12 16 20 24 fe al agitation time (min.) p e r c e n ta g e r e m o v a l 0 20 40 60 80 0 4 8 12 16 20 24 fe al ibtehal k. shakir and besma i. husein 5 ijcpe vol.10 no.2 (june 2009) operating temperature, o c e x tr a c ti o n c o e ff ic ie n t 0.0 0.4 0.8 1.2 1.6 28 32 36 40 44 48 52 fe al fig. (8) extraction coefficient vs. operating temperature, at (ph=1.5, t=10 min., speed=400 rpm, r=3/1, fe conc.=4g/l, and al conc.=4g/l) fig. (9) percentage removal vs. operating temperature, at (ph=1.5, t=10 min., speed=400 rpm, r=3/1, fe conc.=4g/l, and al conc.=4g/l) fig. (10) extraction coefficient vs. phase ratio, at (ph=1.5, t=10 min., speed=400 rpm, t=30oc, fe conc.=4g/l, and al conc.=4g/l) fig. (11) percentage removal vs. phase ratio, at (ph=1.5, t=10 min., speed=400 rpm, t=30oc, fe conc.=4g/l, and al conc.=4g/l) effect of iron concentration the results obtained, here, indicating that increasing the iron concentration in the feed causes the percentage iron removed to decrease as shown in figs.(12 and 13) knowing that a certain number of extraction molecules associated with each metal ion, thus upon keeping other variables constants, the metal concentration in the solvent will remain almost constant in spite of its increase in the aqueous phase. this will cause a reduction in the extraction coefficient. similar results were obtained by islam et al. (9), in the extraction of titanium and iron from acidic sulphate medium. fig. (12) extraction coefficient vs. iron concentration in the feed, at (ph=1.5, t=10 min., speed=400 rpm, t=30oc, r=3/1) operating temperature, o c p e r c e n ta g e r e m o v a l 0 20 40 60 80 28 32 36 40 44 48 52 fe al operating temperature o c lead removal from industrial wastewater by electrocoagulation process 6 ijcpe vol.10 no.2 (june 2009) fig. (13) percentage removal vs. iron concentration in the feed, at (ph=1.5, t=10 min., speed=400 rpm, t=30oc, r=3/1) effect of cyclohexanone concentration the results showed that increasing the extractant concentration the iron removed increase. this could be seen in fig.(14 and 15). the wide range of values of extraction coefficient obtained using different concentration (25, 50, 75, and 100%) may be due to the diluent used which could affects the solvation of the extractant and hence, its extractive properties. this influence could be due to the polar nature of the diluent, which might cause an interaction between the diluent and the extractant. thus, the formation of an extractantdiluent species in the organic phase will produce a lower concentration of the free extractant, with a consequent decrease in the iron removed (10). similar results were obtained by islam et al. (11), in the extraction of ti (іv), fe (iii) and fe (ii) by d2ehpa as the extractant fig. (14) extraction coefficient vs. cyclohexanone concentration, at (ph=1.5, t=10 min., speed=400 rpm, t=30oc, r=3/1, fe conc.=4g/l ) fig. (15) percentage removal vs. cyclohexanone concentration, at (ph=1.5, t=10 min., speed=400 rpm, t=30oc, r=3/1, fe conc.=4g/l) stripping operation effect of ph of the strip solution the results as shown in figs. (16 and 17), indicate that using an acidic (hydrochloric acid) strip solution at ph=1 gave the highest value of the stripping coefficient. however increasing the ph of the strip solution beyond that causing a decrease in the stripping coefficient and percentage removal as noticed from the same figures. this might be attributed to a reveres action due to unstable complex formation between the extracted species and the acid which will lead to a reduction in the stripping coefficient. effect of phase ratio (a/o) the results of this set which are plotted in figs. (18 and 19). these figures indicate that increasing the phase ratio (a/o) lead to an increase in the stripping coefficient up to a limit then decreases in spite of the percentage of iron removal increases up to a limit then it remains nearly constant. thus (3/1) is the best ratio for the cyclohexanone system. this could be attributed to the increase in the volume of aqueous phase which will consequently lead to decrease in the concentration of iron. knowing that the amounts of iron transferred to the aqueous phase are almost constant as it does not require complex formation and therefore, is independent of the amount of aqueous phase used. iron concentration (gm/l) p e r c e n ta g e r e m o v a l 0 20 40 60 80 100 1 3 5 7 9 11 fe al extractant concentration e x tr a c ti o n c o e ff ic ie n t 0 1 2 3 4 5 6 7 8 0.1 0.3 0.5 0.7 0.9 1.1 fe al extractant concentration p e r c e n ta g e r e m o v a l 0 20 40 60 80 100 0.1 0.3 0.5 0.7 0.9 1.1 fe al ibtehal k. shakir and besma i. husein 7 ijcpe vol.10 no.2 (june 2009) fig. (16) stripping coefficient vs. ph, at (r=3/1, fe conc.=3g/l, and al conc.=1g/l) fig. (17) percentage removal vs. ph, at (r=3/1, fe conc.=3g/l, and al conc.=1g/l) fig. (18) stripping coefficient vs. phase ratio, at (ph=1, fe conc.=3g/l, and al conc.=1g/l fig. (19) percentage removal vs. phase ratio, at (ph=1, fe conc.=3g/l, and al conc.=1g/l) conclusions the following conclusions are drawn from this investigation: 1. it was found that cyclohexanone is an active extractant for the iron recovery but it isn't a suitable for the aluminum recovery. 2. the separation of iron from aluminum can be obtained at ph =1.5. this point gave a highest value of extraction coefficient (1.4497) and the percentage of iron removal (81.3%). 3. a phase ratio (o/a) of (3/1) gave the highest extraction coefficient for the conditions (agitation time =10 min, agitation speed =400 rpm, operating temperature =30 o c) used for the system. 4. when the iron concentration decreased in the aqueous feed, the extraction coefficient increased. 5. for the given conditions, the extraction coefficient increased when the concentration of extractant increased. 6. in the stripping operation, it was observed, that using a phase ratio (a/o) of about (3/1) and ph=1, the strip solution gave the highest stripping coefficient, for the conditions used in the system. nomenclature e= extraction coefficient o/a= phase ratio (organic/aqueous) β= selectivity ph s tr ip p in g c o e ff ic ie n t 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 0.0 0.6 1.2 1.8 2.4 fe al ph p e r c e n ta g e r e m o v a l 25 35 45 55 65 75 85 0.0 0.6 1.2 1.8 2.4 fe al phase ratio strip ping coe fficie nt 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 fe al phase ratio p e r c e n ta g e r e m o v a l 20 30 40 50 60 70 80 90 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 fe al lead removal from industrial wastewater by electrocoagulation process 8 ijcpe vol.10 no.2 (june 2009) references 1. al-hemiri a.a. and wadood t.m."extraction of iron from aqueous chloride media" "eng.j.3(5), p41-52"(1999). 2. reddy, m.l. p., and saji, j., " recovery of high purity iron (iii) , titanium (iv) and vanadium (v) from waste chloride liquors from the chloride metallurgy, (2002), www.metsoc.org/conferences/ chloride2002/session8.pdf . 3. arifien, a. e., amrallah, a. h., awadallah, r. m., and sirry , s. m., " temperature effects on solvent extraction of fe ( iii ) , co ( ii ) , ni ( ii ) and cu ( ii ) with thiourea monophosphazene and synergic effect of tributyl phosphate on co ( ii)extraction " , www.acadjournal.com/2003/v9/part2/p2/tempar ature–effects. pdf. 4. costa, m., carvalho, a., uryga, a., and paiva, a., "solvent extraction of iron(iii) from hydrochloric acid solutions using n,n′dimethyl-n,n′-diphenylmalonamide and n,n′dimethyl-n,n′-diphenyltetradecylmalonamide", solvent extraction & ion exchange, vol.21, sep.(2003),p.653, www.dekker.com/servlet/product/productid/sel/ toc. 5. remya, p.n., pavithran, r., and reedy, m.l.p.,"3-phenyl-4-acyl-5-isoxazolones as reagents for the solvent extraction separation of titanium(iv) and iron(iii) from multivalent metal chloride solutions", solvent extraction & ion exchange,vol.22,(2004), www.dekker.com/servlet/product/productid/sel/ toc. 6. ritcey, g. m. and ashbook, a.w., solvent extraction, "priciple and application to process metallurgy ", vol. 1, elsevier, (1984). 7. sykes,p.,"aguidbook to mechanism in organic chemistry " ,6 th edition ,(1986). 8. ritcey, g.m., and ashbook, a.w., solvent extraction, vol.2, elsevier, (1979). 9. islam , m. f., biswas , r. k. , and mustafa , c. m. , " solvent extraction of ti ( iv ) , fe ( iii ) and fe ( ii ) from acidic – sulphate medium with di-0-tolyle phosphoric acidic benzene – hexan-1-01 system; a separation and mechanism study", hydrometallurgy, 13 ( 1985 ), pp. 365 – 373 . 10. ritcey, g.m., and lucas, b.h., "proceeding of the international solvent extraction conference ", lyon 1974, pub. soc. chem.ind., london, pp. 2437-2481. 11. islam, f., rahman, h., and ali, m., "solvent extraction separation study of ti (iv) fe (ii) from aqueous solutions with di-2-ethyl hexyl phosphoric acid in benzene", j. inorg. nucl. chem., (1979), vol. 41, pp. 271-221. 12. alyaa kh.m."extraction of iron from aqueous chloride media in presence of aluminum" thesis, university of baghdadcollege of engineering (2005). بوجود االلمينوم كلوريذاستخالص الحذيذ من وسط ودود طاهر محمد و علياء خضير مجيد العراق-جامعة بغداد-كلية الهندسة–قسم الهندسة الكمياوية الخالصة دراست اسخخالص انحذيذ يٍ وسط كهىريذي يائي بىجىد األنًُيىو بأسخخذاو اَىاع يخخهفت يٍ اهخى هذا انبحث ب , سزػت انًشج, سيٍ انًشج, درجت انحايضيت) وبًخخهف قيى(داي ايثايم كيخىٌ, حزايُيىحايم فىسفاث, سايكهىهكساَىٌ)انًسخخهصاث .(حزكيش انحذيذ في انهقيى وحزكيش انًادة انًسخخهصت , َسبت انطىر .ػًهيت اَخشاع انحذيذ يٍ انًحانيم انؼضىيت ُدرسج ايضا بًخخهف قيى درجت انحايضيت نهًحهىل انًُخشع وَسبت انطىر .اسخؼًم جهاس األيخصاص انذري نقياص حزكيش كم يٍ انحذيذ واألنًُيىو في انطىر انًائي ونجًيغ انخجارب : افضم انقيى نًؼايم االسخخالص ويؼايم االَخشاع حى انحصىل ػهيها ححج ظزوف انخشغيم انًبيُت في انجذول االحي حزكيش انًادة انًشخخهصت َسبت انطىر (يائي/ػضىي ) درجت انحزارة ( وَََ) سزػت انًشج دورة ) (دقيقت/ سيٍ انًشج (دقيقت) درجت انحايضيت انُظاو انؼًم 50% سايكهىهكساَىٌ االسخخالص 1,5 10 400 30 3/1 50% 1/3 االَخشاع 1 http://www.acadjournal.com/2003/v9/part2/p2/temparature�effects http://www.acadjournal.com/2003/v9/part2/p2/temparature�effects http://web9.epnet.com/authhjafdetail.asp?tb=1&_ug=sid+e5f4b961%2d8b06%2d47cc%2d971a%2d174fd60bf2fe%40sessionmgr6+dbs+aph+cp+1+5cd6&_us=hs+true+cst+0%3b1%3b2+or+date+ss+so+sm+ks+sl+0+dstb+ks+ri+kaaacb4a00038542+810e&_uso=hd+false+st%5b0+%2dsolvent++extraction+tg%5b0+%2d+clv%5b0+%2dy+db%5b0+%2daph+cli%5b0+%2dft+op%5b0+%2d+59d0&db=aphjnh&bs=jn%20%22solvent%20extraction%20%26%20ion%20exchange%22&fc=t http://www.dekker.com/servlet/product/productid/sel/toc http://www.dekker.com/servlet/product/productid/sel/toc 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http://web9.epnet.com/authhjafdetail.asp?tb=1&_ug=sid+e5f4b961%2d8b06%2d47cc%2d971a%2d174fd60bf2fe%40sessionmgr6+dbs+aph+cp+1+5cd6&_us=hs+true+cst+0%3b1%3b2+or+date+ss+so+sm+ks+sl+0+dstb+ks+ri+kaaacb4a00038542+810e&_uso=hd+false+st%5b0+%2dsolvent++extraction+tg%5b0+%2d+clv%5b0+%2dy+db%5b0+%2daph+cli%5b0+%2dft+op%5b0+%2d+59d0&db=aphjnh&bs=jn%20%22solvent%20extraction%20%26%20ion%20exchange%22&fc=t http://www.dekker.com/servlet/product/productid/sel/toc http://www.dekker.com/servlet/product/productid/sel/toc iraqi journal of chemical and petroleum engineering vol.12 no.3 (september 2011) 11-24 issn: 1997-4884 experimental study on carbon steel corrosion and its inhibition using sodium benzoate under different operating conditions basim o.hassan, huda d.abdul kader, and marwa f.abdul-jabbar al-nahrain university ,chemical engineering department,baghdad ,iraq abstract corrosion experiments were carried out to investigate the effect of several operating parameters on the corrosion rate and corrosion potential of carbon steel in turbulent flow conditions in the absence and presence of sodium benzoate inhibitor using electrochemical polarization technique. these parameters were rotational velocity (0 1.57 m/s), temperature (30 o c – 50 o c), and time. the effect of these parameters on the corrosion rate and inhibition efficiency were investigated and discussed. it was found that the corrosion rate represented by limiting current increases considerably with increasing velocity and temperature and that it decreased with time due to the formation of corrosion product layer. the corrosion potential shifted to more positive with increasing temperature and velocity while it shifted to more negative with time. sodium benzoate gave good inhibition efficiency for the whole investigated range of temperature and velocity. its efficiency was high on clean surfaces and decreased with time in stationary and flow conditions. no noticeable effect of temperature on the inhibition efficiency was noticed. keywords: corrosion rate, polarization curve, sodium benzoate, carbon steel, inhibition efficiency. الخالصة تى اخشاء عذة تداسب عهٗ عًهٛت انتآكم ٔانتٙ يٍ خالنٓا تى استُتاج تؤثٛش بعض انعٕايم انعًهٛت انًؤثشة عهٗ يعذل انتآكم شٖ انًضطشب بغٛاب أ بٕخٕد بُضٔاث انصٕدٕٚو كًاَع تآكم ٔباستخذاو ٔفٕنتٛت انتآكم نهكاسبٌٕ انفٕالر٘ فٙ انًد تقُٛاث انكٓشٔكًٛٛأٚت انقطبٛت. ْٔزِ انعٕايم ْٙ انسشعت انذٔساَٛت, دسخت انحشاسة, ٔانضيٍ. ٔتى يُاقشت تؤثٛش ْزِ انًحذد ٚتُاقص يع انضيٍ َتٛدت انعٕايم عهٗ يعذل انتآكم ٔكفاءة انًاَع . نقذ ٔخذ بؤٌ يعذل انتآكم انًتًثم بتٛاس انتآكم نتكٍٕٚ طبقت يٍ َٕاتح انتآكم ٔٚضداد يع انسشعت ٔدسخت انحشاسة. إٌ فٕنتٛت انتآكم تتدّ َحٕ صٚادة أكثش يع صٚادة دسخت انحشاسة ٔانسشعت بًُٛا تتُاقص بضٚادة انضيٍ. بُضٔاث انصٕدٕٚو تعطٙ كفاءة خٛذة ٔكفاءتٓا تكٌٕ عانٛت نهسطٕذ انُظٛفت ة عهٗ كفاءة انًاَعص يع انضيٍ فٙ انظشٔف انساكُت ٔظشٔف اندشٚاٌ يع يالحظت عذو ٔخٕد تؤثٛش نذسخت انحشاسٔتتُاق فٙ ْزِ انظشٔف. introduction corrosion is defined as the destruction or deterioration of a material because of reaction with its environment [1].corrosion in aqueous environment and atmospheric environment is an electrochemical process because corrosion involves the transfer of electrons between a metal surface and an aqueous electrolyte solution. it results from the overwhelming tendency of metals to react electrochemically with ,oxygen, water and other substances in the aqueous environment [2] . carbon steel, the most widely used engineering material, accounts for approximately 85% of the annual steel university of baghdad college of engineering iraqi journal of chemical and petroleum engineering experimental study on carbon steel corrosion and its inhibition using sodium benzoate under different operating conditions 12 ijcpe vol.12 no.3 (september 2011) -available online at: www.iasj.net production worldwide. despite its relatively limited corrosion resistance, carbon steel is used in large amounts in marine applications, chemical processing, petroleum production and refining, construction and metal processing equipment [3].when carbon steel is immersed in a neutral aqueous environment, the anodic reaction is [4]: fe → fe +2 + 2e − (1) the cathodic reaction is: o2 + 2h2o +4e − → 4oh − (2) an inhibitor is a chemical substance , when added in small concentration to an environment. effectively decreases the corrosion rate. there are several classes of inhibitors: passivators, organic inhibitors, including slushing compounds and pickling inhibitors, and vapor -phase inhibitors [5].the concentration of a given inhibitor needed to protect a metal will depends on a number of factors: such as the composition of the environment, temperature, the velocity of the liquid, the presence or absence of the metal, the internal or external stresses on the metal, composition of the metal, and the presence of any other metal content [6]. several inhibitors have been used to prevent corrosion of carbon steel in aqueous solution such as chromate molybdate pertechnitate ,nitrate , phosphate, silicates, cations, organic inhibitors, carboxylates and tannins[7]. increasing temperature affects the corrosion rates by a combination of factorssuch as; the common effect of temperature on the reaction kinetics themselves and the higher diffusion rate of many corrosive by products at increased temperatures. many corrosive gases have lower solubility in open systems at higher temperatures, as temperatures increase, the resulting decrease in the solubility of the gas causes corrosion rates to go down[5] . in the case of corrosion in neutral solution, the increase of temperature has favourable effect on the overpotential of oxygen depolarization and the rate of oxygen diffusion, but it leads to a decrease of oxygen solubility [8]. velocity has a significant effect on corrosion rates. stagnant or low velocity fluids usually give low general corrosion rates. corrosion rates generally increase with increasing velocity due to the depolarizing effect on the cathode [9].velocity primarily affects corrosion rate through its influence on diffusion phenomena. it has little effect on activation controlled processes. the manner in which velocity affects the limiting diffusion current is a marked function of the physical geometry of the system. in addition, the diffusion process is affected differently by velocity when the flow conditions are laminar as compared to the situation where turbulence exists [4]. when iron or steel is exposed to high temperature water, the rate of corrosion of the metal decrease with exposure time during the early period of exposure. after several hours, the corrosion rate becomes relatively constant at a lower value. during the early period of exposure, while the corrosion rate is decreasing, the oxide film on the surface of the metal grows in thickness. however, the rate at which the film grows decreases with time. the thickness of the oxide film soon reaches a relatively constant value, and thereafter film thickness does not change appreciably with basim o.hassan, huda d.abdul kader, and marwa f.abdul-jabbar -available online at: www.iasj.net ijcpe vol.12 no.3 (september 2011) 13 further exposure. as might be expected, a relatively constant corrosion rate and oxide film thickness are attained at about the same time. this process, referred to as pretreatment or pickling involves careful control of reactor coolant water chemistry and temperature during the pretreatment period. several previous studies [10,11,12] showed that the corrosion rate generally decreases with time due to corrosion product formation depending on flow velocity. slaiman and husan [12] noticed that at high velocity, the formation of corrosion product leads to increasing the limiting current density (corrosion rate) for carbon steel in water by increasing the turbulence resulted from the increased roughness of the surface. in many corrosion problems, the rate of uniform corrosion is controlled by the rate of mass transfer. this is true whether the corrosion fluid remains static or in fast motion with respect to the metal surface. however, molecular diffusion is not the only factor which influences the rate of corrosion. in addition, in turbulent fluids, the rate of transport of eddy diffusion appears to participate in the control of the over-all transfer rate. it is only in situations where both anodic and cathodic processes are activation controlled that they will be unaffected by the relative movement between surface and environment [4,13].the rate of this half reaction is generally limited by the speed at which oxygen can reach the surface of the metal. this oxygen is transported from the bulk water to the surface across the boundary layer by diffusion [14]. sodium benzoate has found considerable application as a corrosion inhibitor in low concentrations. corrosion inhibition has been reported for carbon steel, zinc, copper, copper alloys, soldered joints, aluminum, and aluminum alloys. as a liquid phase inhibitor, low concentrations of sodium benzoate have reportedly been used for corrosion control at a ph as low as 5.5. movement of the solution, or saturation with oxygen assists inhibition, but a ph below 6 causes breakdown. the most effective inhibition appears to be in the ph range of 6 to 12 [15]. the aim of present work is to study the effect of some operating parameters on the corrosion of carbon steel and its inhibition in 0.1n nacl solutions by sodium benzoate as inhibitor using electrochemical polarization technique to assess the effect of velocity, temperature, and time on the corrosion rate in the presence and absence of inhibitor. expermental work figure 1 shows the experimental apparatus that was used for performing the experimental work. experimental study on carbon steel corrosion and its inhibition using sodium benzoate under different operating conditions 14 ijcpe vol.12 no.3 (september 2011) -available online at: www.iasj.net fig. 1 experimental apparatus 1power supply, 2ammeter, 3resistance box, 4voltmeter, 5stirrer, 6working electrode (specimen), 7graphite electrode (anode),8-calomel electrode (reference electrode), 9water bath, 10brush, 11 luggin capillary, 12metal for electrical connection with specimen,13beaker containing the solution. the experimental apparatus was composed of a mechanical agitator to obtain different rotational velocities, a water bath to obtain different solution temperatures, a carbon steel specimen of 30 mm long and 25 mm outside diameter (cathode) attached to the rod of the agitator, power to apply the required protection potential, a digital ammeter to measure the current, a digital voltemeter to measure potential, variable resistance (rheostate) to control the current flow, a graphite electrode as auxiliary electrode (anode), a saturated calomel electrode (sce) as a reference electrode, and a digital balance of high accuracy. the electrical connection between cathode (specimen) and the cell was attained using brush. before each experiment the specimen was washed by tap water followed by distilled water, dried with clean tissue, abraded using different grades of emery papers, 500,600,1000 and 1200 immersed in annular acetone for 5 minutes, rinsed with water and dried with clean tissue. then the specimen was stored in vacuum desiccator over high activity silica gel for 24 h before use. five liters of 0.1n nacl solution was used in water bath at different temperatures (30°c, 40°c and 50 o c) at stationary conditions. for flow conditions, different rotation speeds (250, 500,750, 1200 rpm) were investigated at constant temperature of 40 o c . the specimen was connected to –ve terminal of power supply to serve as a cathode and the graphite to +ve terminal to serve as an anode. when the solution reached the required temperature, the specimen was immersed in the solution and the electrical circuit was switched on immediately. the power supply was set at 5v (applied voltage). the specimen (working electrode) was cathodically polarized from potentials (-1.3 to -1.5 v) to the corrosion 12 11 10 1 + 4 3 2 6 5 9 13 6 8 7 basim o.hassan, huda d.abdul kader, and marwa f.abdul-jabbar -available online at: www.iasj.net ijcpe vol.12 no.3 (september 2011) 15 potential (where iapp. =0) by changing the applied current using rheostat. the current was recorded for each 5 mv change in potential. two minutes were allowed for steady state to be reached after each potential increment and the capillary tube was placed at distance 12 mm from cathode (specimen) and connected to calomel electrode to measure the specimen potential [16]. thus polarization curve can be drawn and the limiting current can be obtained. the distance between anode and cathode was 100 mm. the experiments were repeated by adding 1500 ppm sodium benzoate to the solution as corrosion inhibitor; then the polarization curve was drawn to obtain the limiting current at different temperatures (30, 40 and 50 o ) at stationary conditions, and at different speeds (250, 750,1200 rpm) at constant temperature of 40 o c . the effect of time on the corrosion rate (il) and inhibition efficiency was determined by measuring il at various time intervals, (t= 0 h) ,(t= 1.5 h) and (t = 3 h) at t = 40 o c for each value of rotation speed. after determining the polarization curve at t = 0 the specimen was allowed to corrode freely by switching off the electrical circuit for 1.5 h and then the polarization curve was obtained. after obtaining the polarization curve at t = 1.5h, the electrical circuit was switched off again to allow the specimen to corrode freely for another 1.5 h (the total time is 3 h). then the circuit was switched on and the polarization curve is obtained for t = 3 h. since the limiting current plateau is not well defined, the limiting current was determined by using gabe [17] method as in fig.2. 2 21 ii i l   (3) since the solution is neutral (ph = 7), il = icorr. [4,5]. the inhibition efficiency was calculated as: o o i ii ie )(   % (4) where io is the limiting current in absence of inhibitor and i is the limiting current in the presence of the inhibitor. fig. 2 determining limiting current table 1, values of il at various temperatures and stationary condition. results and discussions table (1) to (3) show the numerical values of experimental results. temperature ( o c ) il (ma/m 2 ) without inhibitor with 1500 ppm sodium benzoate 30 1697.65 3 891.2 68 40 2546.47 9 2122. 066 50 3395.30 5 2546. 479 e e1 i2 i1 i e experimental study on carbon steel corrosion and its inhibition using sodium benzoate under different operating conditions 16 ijcpe vol.12 no.3 (september 2011) -available online at: www.iasj.net table 2, values of il at various velocities and times at t = 40 o c . without inhibitor effect of temperature figure 3 shows the polarization curve time at stationary conditions and different temperatures (30°c, 40°c and 50°c).from this figure, it can be seen that as the temperature increases the limiting current increases. this can be ascribed to two reasons: first when the temperatures increases, the o2 diffusivity increases enhancing the corrosion [4,5] and second it decreases the o2 solubility the factor that leads to decrease the corrosion rate [4]. also fig.(3) shows that the corrosion potential shifts to more positive with increasing temperature. the rise in temperature may decrease the equilibrium potential of fe and h2 but increase the equilibrium potential of o2 [18], the increase the diffusion rate of oxygen species by increasing the molecular diffusion coefficient and decreases the oxygen solubility. effect of rotational velocity the polarization curves at different rotational speed (0, 0.3271, 0.9812, and 1.57 m/s) at 40°c are shown in fig.(4). in this figure it is clear that the limiting current increases as the rotational velocity increases due to increase in o2 diffusion from solution bulk to the surface and decreasing the thickness of diffusion layer on the metal surface[11,19,20,12]. evans 1960 [21] indicated that greater turbulence due to high velocities results in more uniform o2 concentration and more likely initiation of corrosion on a previously uncorroded surface. polarization curve for velocity of 0.6542 and 1.3083 m/s are not presented in fig.(4) to avoid confusion. also fig.(4) shows that the ecorr. shifts to more positive with increasing velocity due to the increased o2 transport to the surface. this agrees with previous findings [20,11,22,23]. fig. 3 polarization curve at stationary conditions at different temperatures 0.00 0.01 0.10 1.00 10.00 100.00 1000.00 i (ma) -1.60 -1.40 -1.20 -1.00 -0.80 -0.60 p o te n ti a l (v ), s c e temperature 30°c 40°c 50°c velocity (m/s) il (ma/m 2 ) t = 0 h t = 1.5 h t = 3 h without inhibitor with 1500 ppm sodium benzoate without inhibitor with 1500 ppm sodium benzoate without inhibitor with 1500 ppm sodium benzoate 0 8492.569 4246.285 5520.170 3397.028 4670.913 2972.399 0.3271 8067.941 5095.541 6369.427 4246.285 4246.285 3397.028 0.9812 12314.225 6369.427 8917.197 5944.798 8067.941 5520.170 1.57 12738.854 6794.055 9341.826 6369.428 8492.569 5944.798 basim o.hassan, huda d.abdul kader, and marwa f.abdul-jabbar -available online at: www.iasj.net ijcpe vol.12 no.3 (september 2011) 17 fig. 4 polarization curve at t=40°c at different rotational velocity effect of time over the years, some studies investigated the effect of carbon steel corrosion products on the corrosion rate [10,11,12]. most of these studies used the weight loss method and not the electrochemical technique (lcd). in fact, the loss in weight gives the average weight loss over the exposure period and not the instantaneous. in the present work the lcd technique was used to determine the instantaneous corrosion rate (il) at various times of exposure. figures 5 through 7 show the polarization curves for different rotational velocities. the figures show that for all velocities , il decreases with time. the corrosion potential decreases (becomes more negative) with increasing time. this decrease is ascribed to the formation of corrosion product layer with time which leads to the decrease of the arrival of o2 to the metal surface [10,11,12]. also the surface activity decreases with time [10]. it is evident from figs 5 to 7 that the corrosion potential shifts to more negative with time. this decrease in ecorr is due to the decrease in o2 concentration near the surface due to the formation of corrosion product layer [10,20]. it was found that ecorr decreases with time and with the decrease in o2 concentration. fig. 5 polarization curve at t= 40°cand u= 0.3271 m/s for different times fig. 6 polarization curve at t=40°c and u=0.9812 m/s for different times fig. 7 polarization at t=40°c and u= 1.57 m/s for different times addition of inhibitor (1500 ppm sodium benzoate) the effect of sodium benzoate inhibitor on corrosion behavior of carbon steel in chloride neutral media is presented in figures 8 through 25. it can be seen from all figures that the 0.10 1.00 10.00 100.00 1000.00 i (ma) -3.00 -2.00 -1.00 0.00 p o te n ti a l (v ), s c e rotational velocity u = 0 m/s u = 0.3271 m/s u = 0.9812 m/s u = 1.57 m/s 0.00 0.00 0.01 0.10 1.00 10.00 100.00 i (ma) -2.00 -1.60 -1.20 -0.80 -0.40 p o te n ti a l (v ), s c e u = 0.3271 m/s t = 0 h t = 1.5 h t = 3 h 0.00 0.00 0.01 0.10 1.00 10.00 100.00 1000.00 i (ma) -2.40 -2.00 -1.60 -1.20 -0.80 -0.40 p o te n ti a l (v ), s c e u = 0.9812 m/s t = 0 h t = 1.5 h t = 3 h 0.00 0.01 0.10 1.00 10.00 100.00 1000.00 i (ma) -2.40 -2.00 -1.60 -1.20 -0.80 -0.40 p o te n ti a l (v ), s c e u = 1.57 m/s t = 0 h t = 1.5 h t = 3 h experimental study on carbon steel corrosion and its inhibition using sodium benzoate under different operating conditions 18 ijcpe vol.12 no.3 (september 2011) -available online at: www.iasj.net limiting current decreases with the addition of the inhibitor. effect of temperature figures 8 through 10 show the polarization curve at stationary condition and different temperatures (30°c, 40°c and 50°c) in absence and presence of sodium benzoate. it is clear that the sodium benzoate leads to decreasing the corrosion rate considerably. the figures show that the temperatures have no noticeable effect on the inhibitor efficiency .it is noticed that the inhibitor (sodium benzoate) shifts the corrosion potential to be more active indicating that it is a cathodic type inhibitor. cathodic inhibitors reduce corrosion by retarding individual stages of the cathode reaction: ionization of oxygen, diffusion of oxygen to the cathode, and discharge of hydrogen ions which naturally cannot lead to local corrosion. in the presence of sodium benzoate as cathodic inhibitors. a considerable part of the electrode remains inert with regard to the cathodic process, and this reduces the corrosion current sharply. [4,24]. fig. 8 polarization curve at 30°c in absence and presence of sodium benzoate inhibitor fig. 9 polarization curve at 40°c in absence and presence of sodium benzoate inhibitor fig. 10 polarization curve at 50°c in absence and presence of sodium benzoate inhibitor effect of rotational velocity figure 11 shows the effect of rotational velocity on the il in presence and absence of sodium benzoate. when the electode rotation velocity increased, the cathodic current increased.the increase of cathodic current with the electrode rotation velocity is explained by an increase of the oxygen supply to the metal surface [25]. fig.(11) reveasls that the presence of 1500 sodium benzoate lead to considerable decrease in il (or the corrosion) rate. table (3) lists values of ie with velocity but it is generally decreases with increasing velocity. this may be attributed to the removal of inhibitor layer due to high shear 0.00 0.00 0.01 0.10 1.00 10.00 100.00 1000.00 i (ma) -1.60 -1.40 -1.20 -1.00 -0.80 -0.60 p o te n ti a l (v ), s c e stationary blank 1500 ppm sodium benzoate 0.00 0.00 0.01 0.10 1.00 10.00 100.00 1000.00 i (ma) -1.60 -1.40 -1.20 -1.00 -0.80 -0.60 p o te n ti a l (v ), s c e stationary blank 1500 ppm sodium benzoate 0.00 0.00 0.01 0.10 1.00 10.00 100.00 1000.00 i (ma) -1.40 -1.20 -1.00 -0.80 -0.60 p o te n ti a l (v ), s c e stationary blank 1500 ppm sodium benzoate basim o.hassan, huda d.abdul kader, and marwa f.abdul-jabbar -available online at: www.iasj.net ijcpe vol.12 no.3 (september 2011) 19 forces near the surface as evidenced by numerous studies [26,27,28]. effect of time on the inhibitor effect the limiting current was measured at various times in the presence of the corrosion inhibitor (sodium benzoate), to determine the effect of time on the inhibition efficiency. figures 12 to 23 show the polarization curves at various times for various velocities in the presence and absence of corrosion inhibitor at 40 o c. figures 12 to 15 show the polarization curves at stationary conditions. it is clear that the presence of the inhibitor leads to decreasing il (or corrosion rate) at different times ( 0,1.5, 3h). the same behavior is clear in figures 15 to 22 for flow conditions. this indicates that sodium benzoate function even in the presence of corrosion product. it is clear that the presence of inhibitor leads to decreasing the corrosion rate with inhibition percent (%ie )for all time . from table (3), the ie decreases with increasing time. this is due to the fact that the inhibiting effect of soduim benzoate is due to the occlusion of the metal surface and not adsorption because the inhibitor is a viscofier and thickner. the inhibitor could thus form a layer on the surface, restricting ingress of the corrodent. the efficiency decreases with increasing the time because the inhibitor layer starts to remove with increasing turbulence due to the formation of corrosion products [29]. fig.. 11 il vs. rotational velocity in absence and presence of sodium benzoate inhibitor fig. 12 polarization at time =0 h in absence and presence of sodium benzoate inhibitor at 40°c fig. 13 polarization at time =1.5 h in absence and presence of sodium benzoate inhibitor at 40°c 0.00 0.00 0.00 0.01 0.10 1.00 10.00 100.00 i (ma) -2.40 -2.00 -1.60 -1.20 -0.80 -0.40 p o te n ti a l (v ), s c e t= 1.5 hr blank t = 1.5 with 1500 ppm soduim benzoate  blank *with 1500 ppm sodium benzoate i c o rr .( m a /m 2 ) experimental study on carbon steel corrosion and its inhibition using sodium benzoate under different operating conditions 20 ijcpe vol.12 no.3 (september 2011) -available online at: www.iasj.net fig. 14 polarization at time =3 h in absence and presence of sodium benzoate inhibitor at 40°c fig. 15 polarization at time =0 h and u= 0.3271 m/s in absence and presence of sodium benzoate inhibitor at 40°c fig. 16 polarization at time =1.5 h and u= 0.3271 m/s in absence and presence of sodium benzoate inhibitor at 40°c fig. 17 polarization at time =3 h and u= 0.3271 m/s in absence and presence of sodium benzoate inhibitor at 40°c fig. 18 polarization at time =0 h and u= 0.9812 m/s in absence and presence of sodium benzoate inhibitor at 40°c fig.19 polarization at time =1.5 h and u= 0.9812 m/s in absence and presence of sodium benzoate inhibitor at 40°c 0.00 0.01 0.10 1.00 10.00 100.00 i (ma) -3.00 -2.50 -2.00 -1.50 -1.00 -0.50 p o te n ti a l (v ), s c e t= 3 hr blank t = 3 hr with 1500 ppm soduim benzoate 0.00 0.00 0.00 0.01 0.10 1.00 10.00 100.00 i (ma) -2.00 -1.60 -1.20 -0.80 -0.40 p o te n ti a l (v ), s c e u= 0.3271 m/s t= 0 hr blank t=0 hr with 1500 ppm sodium benzoate 0.00 0.00 0.01 0.10 1.00 10.00 100.00 i (ma) -2.40 -2.00 -1.60 -1.20 -0.80 -0.40 p o te n ti a l (v ), s c e u= 0.3271 m/s t= 1.5 hr blank t= 1.5 hr with 1500 ppm sodium bezoate 0.00 0.00 0.00 0.01 0.10 1.00 10.00 100.00 i (ma) -3.00 -2.50 -2.00 -1.50 -1.00 -0.50 p o te n ti a l (v ), s c e u= 0.3271 m/s t = 3 hr blank t= 3 hr with 1500 ppm sodium benzoate 0.00 0.00 0.00 0.01 0.10 1.00 10.00 100.00 1000.00 i (ma) -2.40 -2.00 -1.60 -1.20 -0.80 -0.40 p o te n ti a l (v ), s c e u= 0.9812 m/s t = 0 h blank t= 0 h with 1500 ppm sodium benzoate 0.00 0.00 0.00 0.01 0.10 1.00 10.00 100.00 1000.00 i (ma) -2.40 -2.00 -1.60 -1.20 -0.80 -0.40 p o te n ti a l (v ), s c e u = 0.9812 m/s t = 1.5 h blank t= 1.5 h with 1500 ppm sodium benzoate basim o.hassan, huda d.abdul kader, and marwa f.abdul-jabbar -available online at: www.iasj.net ijcpe vol.12 no.3 (september 2011) 21 fig. 20 polarization at time =3 h and u= 0.9812 m/s in absence and presence of sodium benzoate inhibitor at 40°c fig. 21 polarization at time =0 h and u=1.57 m/s in absence and presence of sodium benzoate inhibitor at 40°c fig. 22 polarization at time =1.5 h and u= 1.57 m/s in absence and presence of sodium benzoate inhibitor at 40°c figure 24 shows the effect of temperature on il (or corrosion rate) in the absence and in the presence of inhibitor. the current density in the absence of sodium benzoate is higher than that of the presence of it for all temperatures. it is evident form fig. (24) that the temperature has no effect on the inhibition efficiency where the inhibitor still functions even at high temperature. in fig. (24) the icorr. for the presence of inhibitor is lower than that in the blank. the corrosion current density in cooling water decreased considerably in the presence of inhibitor for oxygen reduction as a result of cathodic inhibitor. table (3) shows the numerical values of percentage inhibition efficiency of experimental results. table (3) percentage of inhibition efficiency of 1500 ppm sodium benzoate velocit y (m/s) % inhibition efficiency t = 0 h t = 0 h t = 0 h 0 50 50 50 0.3271 36.84 36.84 36.84 0.9812 48.28 48.28 48.28 1.57 46.67 46.67 46.67 fig. 23 polarization at time =3 h and u=1.57 m/s in absence and presence of sodium benzoate inhibitor at 40°c 0.00 0.00 0.00 0.01 0.10 1.00 10.00 100.00 1000.00 i (ma) -2.50 -2.00 -1.50 -1.00 -0.50 p o te n ti a l (v ), s c e u= 0.9812 m/s t= 3 h blank t= 3 h with 1500 ppm sodium benzoate 0.01 0.10 1.00 10.00 100.00 1000.00 i (ma) -2.40 -2.00 -1.60 -1.20 -0.80 -0.40 p o te n ti a l (v ), s c e u= 1.57 m/s t= 0 h blank t= 0 h with 1500 ppm sodium benzoate 0.01 0.10 1.00 10.00 100.00 1000.00 i (ma) -3.00 -2.50 -2.00 -1.50 -1.00 -0.50 p o te n ti a l (v ), s c e u= 1.57 m/s t= 1.5 h blank t= 1.5 h with 1500 ppm sodium benzoate 0.01 0.10 1.00 10.00 100.00 1000.00 i (ma) -3.00 -2.50 -2.00 -1.50 -1.00 -0.50 p o te n ti a l (v ), s c e u= 1.57 m/s t= 3 h blank t= 3 h with 1500 ppm sodium benzoate experimental study on carbon steel corrosion and its inhibition using sodium benzoate under different operating conditions 22 ijcpe vol.12 no.3 (september 2011) -available online at: www.iasj.net i co rr .( m a /m 2 ) δ temperature °c fig. 24 il vs. temperature in absence and presence of sodium benzoate mass transfer mass transfer coefficient can be estimated from data of polarization curves according to equation cf i k l   (5) where k is the mass transfer coefficient, and δc is the oxygen concentration difference between the bulk and surface in solution δc=cbcs, z=4 for oxygen reduction, and il is the limiting current density for oxygen reduction on fe at i=il ,cs=0, cb from table(4) =0.1372 mole /m 3 at 40°c. table (4) values of oxygen diffusivity and solubility at different temperatures [30,31] t ( o c) solubility (mg/l) 0.1 nacl do * 10 9 (m 2 /s) 0.1 nacl cb (mole/m 3 ) 30 7.5 2.374 0.2344 40 4.389 3.010 0.1472 50 5.399 3.562 0.1687 figure 25 shows the variation of mass transfer coefficient with re at the absence and presence of inhibitor. from this fig., it can be seen that as re increase, k increase because the convective mass transport of o2 will increase. increasing turbulence leads to decreasing the thickness of viscous sub-layer and the diffusion layer that represents the main resistance to momentum and mass transport, respectively [32,33]. hence, the o2 concentration at the surface will increase leading to increasing k. the effect of reynolds number on thickness of different sub-layer is shown in fig. (26) in the presence and absence of inhibitor. it can be seen that as the reynolds number increases, the thickness will decrease. this effect of re is due to the increased turbulence and the penetration of eddies through this layer causing a decrease in its thickness [34,35]. k d  (6) fig. 25 effect of re on mass transfer coefficient fig. 26 effect of re on thickness 0.00 20000.00 40000.00 60000.00 80000.00 re 0.08 0.12 0.16 0.20 0.24 0.28 k ( m /s ) blank 1500 ppm sodium benzoate 0.00 20000.00 40000.00 60000.00 80000.00 re 12.00 16.00 20.00 24.00 28.00 blank 1500 ppm sodium benzoate basim o.hassan, huda d.abdul kader, and marwa f.abdul-jabbar -available online at: www.iasj.net ijcpe vol.12 no.3 (september 2011) 23 conclusions for the present work, the followings can be concluded : 1increasing temperature leads to increase the limiting current from 1697.653 ma/m 2 at 30°c to 3395.305 ma/m 2 at 50°c in the absence in inhibitor. 2increasing temperature shifts the corrosion potential to more positive. in 30°c, the potential is 0.99 v while in 40°c and 50°c the calculated are -0.86 v and -0.77 v respectively. 3increasing rotational velocity leads to increase the corrosion rate considerably which represent by limiting current from 8067.971 ma/m 2 at 0.3271 m/s to 12738.854 ma/m 2 at 1.57 m/s in the absence of inhibitor. also it shifts the corrosion potential to more positive from -0.6 v at 0.3271 m/s to -0.5 v at 1.57 m/s. 4 the corrosion rate (or il) decreases considerably with time due to the corrosion products formation. it decreases from 8492.569 ma/m 2 at time zero to 4670.913 ma/m 2 after 3h at 40°c and stationary conditions. also the corrosion potential shifts to more negative, it become -0.76 v after 3 h while in zero time have been 0.57 v at rotational velocity 0.3271 m/s. 5the inhibition efficiency of sodium benzoate decreased considerably with time and slightly with rotational velocity. it decreased from 50% at time zero to 36.36% after 3 h at stationary conditions. while with rotational velocity it is 36.84%, 48.67% at velocities 0.3271 m/s, 0.9812 m/s and 1.57 m/s, respectively. references [1] fontana m.g., greene n.d., (1984), “corrosion engineering”, london , 2nd edition. [2] kruger j., m.sc (2001), "electrochemistry of corrosion", the johns hopkins university, baltimore, md 21218, usa. [3] yen m.s., i.j.wang, daysand, pigments, (2005), 67, 183. [4] shreir l.l., (2000), “corrosion handbook”, part 1, newnes butter, london, 2 nd edition . [5] uhlig, r., herbert h. winston revie, (2008), "corrosion and corrosion control, an introduction to corrosion science and engineering", john wiley &sons, 4 rd edition. [6] kraka e, d. cremer, (222), "computer design of anticancer drugs", j. am. chem. soc., 122, 8245. [7] farr, m. saremi, (1983), “surface technology”, 19, 137. [8] zhuk n.p, (1976), course on corrosion and metal protection, metallurgy, moscow. [9] jones l. w., (1988), “corrosion and water technology for petroleum producers”. [10] mahato b.k., stewrd f.r., and shimlit l. w., (1986), “corrosion sciences”, no. i, vol.8, 737. [11] mahato k., cha c. y. and shemilt u w., (1980), “corrosion sciences”, vol. 20, p. 421 to 441. [12] slaiman and hasan, (december 2010), "study on corrosion rate of carbon steel pipe under turbulent flow conditions", the candian j. of chem. eng., vol. 88. [13] marangozis j., (1986),“corrosion”, no. 8, vol.24, p. 255. [14] smith s. w., mccabe k. m., and black d.w., (1988), “corrosionnace”, no. 1, vol. 45, p. 790. [15] wormwell f, mercer a.d, (may 2007),"sodium benzoate and other metal benzoates as corrosion inhibitors in water and in aqueous experimental study on carbon steel corrosion and its inhibition using sodium benzoate under different operating conditions 24 ijcpe vol.12 no.3 (september 2011) -available online at: www.iasj.net solutions", journal of chemical technology and biotechnology. [16] pickett d.j. and k.l. ong, (1974), electrochmical acta, vol. 19, p. 875. [17] gabe d.r. and p.a. makanjoula, (1986), efcf publication series no. 15, electrochemical eng., aiche symposium series, no. 98, p.309. [18] cifuentes, (november1987),“anti-corrosion”, p.4 to 6. [19] poulson, (1983), corrosion science, no. 1, vol. 23, p. 391. [20] foroulis z. a., (1979), corrosion, vol. 35. p.340. [21] evans, ulick. r., (1960), "the corrosion and oxidation of metals", arnold, london. [22] silverman d.c., (1984), “corrosion nace”, no. 5, vol. 40, p. 220. [23] hasan, b.o., (2003), "heat, mass and momentum analogies to estimate corrosion rates under turbulent flow conditions", ph. d. thesis. chem. eng. dep., al-nahrain university, baghdad. [24] olen, l. and riggs, j. (1974), “theoretical aspects of corrosion inhibitors and inhibition” ,nace, houston, texas. [25] francis moran, nathalie ochoa, nadine pebere and bernard tribollet, (2005),"influence of flow on the corrosion inhibition of carbon steel by fatty amines in association with phosphonocarboxylic acid salts", corrosion science, 47, pp. 593-604. [26] musa,a.y, a.h.kadhum, a.b. mohamad, a.r. daud, (2009), "stability of layer forming for corrosion inhibitor on mild steel surface under hydrodynamic conditions", int. j. electrochem. sci.,4, 707-716. [27] toledo, d.m., j.g. rodrigues, m.casales, a.caceres, l. matinez, (2011), "hydrodynamic effects on the co2 corrosion inhibition of x-120 pipline steel by carboxyethlimidazoline", int. j. electrochem. sci.,6, 778792. [28] qasim j. m. slaiman, basim o. hasan and hussein a. mahmood, (april 2008), “ corrosion inhibition of carbon steel under two-phase flow (water–petroleum) simulated by turbulently agitated system" canadian j. of chemical engineering, vol. 86, 240-248. [29] noreen anthony, h.benita sherine, and susai rajendran, (2009), "investigation of inhibiting effect of carboxymethyicellulose – zn +2 system on chloride solution", the arabian j for science and engineering, vol.35, 2a. [30] audin a., and l.john, (1972), j. chem. eng. data, no.3, vol. 17, p.789. [31] sense f., (2001), “oxygen solubility”, north california state. [32] welty j. r., c. e. wicks, and g. rorrer, (2001), "fundamental of momentum, heat and mass transfer”, john wiley and sons, united state of america, 4 th edition. [33] nesic n., b. f. m. pots, j. postelthwaaite, and n. trevenot, (1995), j.corrosion science and eng., ph.d. study, vol. 1, paper 3. [34] coulson m. and richardson j. f., (1998), “chemical engineering”, vol.1, butter worth heinemann, britain, 5th edition. [35] brodkey r. s. and hershey h. c., (1989), “transport phenomena”, mc graw hill, new york, 2nd printing. iraqi journal of chemical and petroleum engineering vol.16 no.2 (june 2015) 5760 issn: 1997-4884 using microbubbles to improve transmission oil in pipes hussein hadi hussein petroleum engineering department, college of engineering, university of baghdad abstract drag reduction (dr) techniques are used to improve the flow by spare the flow energy. the applications of dr are conduits in oil pipelines, oil well operations and flood water disposal, many techniques for drag reduction are used. one of these techniques is microbubbles. in this work, reduce of drag percent occurs by using a small bubbles of air pumped in the fluid transported. gasoil is used as liquid transporting in the pipelines and air pumped as microbubbles. this study shows that the maximum value of drag reduction is 25.11%. key words: drag, gasoil, microbubbles, turbulence introduction microbubbles is considered as a method to reduce friction between wall pipes and the liquid that flows by squirt small bubbles into the turbulent confines layer[1]. in a large ship, skin friction causes 80% saving of total drag. this explains why this type of drag reduction is significant for applications on maritime transportation .in this experiment total drag can be reduced by microbubbles, and if gas generation rate increases, drag reduction increases [2]. in the 1980s systematic studies were conducted in water tunnels to study the effects of drag reduction on a flat wall by using microbubbles which were generated by porous plates[3] . according to merkle and deutsch[4], the size of the bubbles is significantly important. the trajectories of the bubbles are affected by their diameters. as a result, both the concentration and the location of the bubbles in the boundary layers will be affected as well. when the bubble sizes are measured, it indicates that the bubble size decreases if free stream speed is increased, but it increases if airflow rate is increased. however, it seems that the injection technique has little effect. merkle and deutsch [4] showed that the sizes of the bubbles are between 500 – 1200 µm. this shows that the range is larger than the thickness of the sublayer which is about 10 µm and smaller than the size of the boundary layer which is about 10 mm. sayyaadi, nematollahi [5]observed that when the speed is high , high injection rate of bubbles is needed. the reason is that high speed pushs the bubbles outside the boundary layer , while at low speed, the bubbles will be near the boundary layer. madavan et al [6] stated that allowing the viscosity and density to vary locally as a function of a prescribed bubble concentration profile simulates the action of bubbles. these results of the model show that if the microbubbles are present, the iraqi journal of chemical and petroleum engineering university of baghdad college of engineering using microbubbles to improve transmission oil in pipes 58 ijcpe vol.16 no.2 (june 2015) -available online at: www.iasj.net   dv  nre 2 4 2 v ldp f     airl qq / substantial skin friction reductions can be obtained. this support the idea that microbubbles can be used as an agent to not only reduce skin friction but reduce overall drag as well. description of experiment 1flow system the schematic of the flow system is depicted in figure 1. the diameter of the pipe is 1 inch while the test section of three meters carbon steel pipe with roughness equal 0.0018, gasoil was used as liquid transporting, and the testing temperature was about 35 °c. 2procedure of experiments the procedure will be followed: a-in the pipe, the gasoil is permitted to flow. bypass section is used to control the flow rate of the liquid. b-the flow rate of the air is changed ctransmitter which is connected to the computer is used to measure the pressure drop. d-procedures a, b and c are repeated for different flow rates of gas oil and air. 3calculations to measure velocity, drag reduction percentage, reynolds number , friction factor, skin friction factor and α ,the following equations are used respectively.[7,8] … (1) … (2) … (3) … (4) … (5) … (6) where: v= velocity (m/sec) , q=flow rate (m 3 /hr) a= inside area of pipe(m 2 ), dr=drag reduction , δpa =pressure drop after air injection(psi), δpb= pressure drop before air injection(psi), nre=reynolds number(dimensionless), µ= dynamic viscosity(c.p) , ρ=density(m 3 /hr), cf: skin friction factor, f=friction factor, l=test section length(m), qair=air flow rate(m 3 /hr), ql=liquid flow rate (m 3 /hr) fig. 1, schematic layout of flow system aqv  100%     b ab p pp dr 58.2 )nre/(log455.0 f c hussein hadi hussein -available online at: www.iasj.net ijcpe vol.16 no.2 (june 2015) 59 results and discussion 1effect of reynolds number fig. (2) shows that the drag reduction increases when reynolds number is increased. the reason behind this is that increasing reynolds number leads to increasing turbulence in the pipe. the figure also shows that for each curve, increasing the air flow rate results in increasing drag reduction. this happens because of the increase in the void fraction in the boundary layer in the pipe. the maximum drag reduction is 25.11%. fig. 2, effect of reynolds number on drag reduction 2friction factor versus reynolds number fig. (3), shows that the friction factor decreases when reynolds number is between 5000 and 6000. then, it starts to increase when reynolds number is 7000. it starts to decrease at 8000 and increase again at 9000.this ripple is due to interaction between microbubbles and the liquid, as the microbubbles interaction results in reducing the friction factor. the increasing of friction factor happens because the effect of microbubbles are low due to the changes in turbulence. this figure also shows that friction factor decrease significantly when the air flow rate increases to 50 l/min. fig. 3, friction factor versus reynolds number 3effect of air flow rate fig. (4) shows drag reduction increases when air flow rate increases for the different liquid flow rate values. when the liquid flow rate is low, the increase dr% will be graduated. however, when the liquid flow rate increases, a sudden drag reduction can be observed because of the increasing of turbulence. fig. 4 effect of air flow rate on drag reduction nre d r % 0 5 10 15 20 25 30 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 qair=20l/min qair=30l/min qaie=50l/min nre f 0.00 0.01 0.02 0.03 0.04 0.05 0.06 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 qair=20l/min qair=30l/min qaie=50l/min using microbubbles to improve transmission oil in pipes 60 ijcpe vol.16 no.2 (june 2015) -available online at: www.iasj.net 4skin friction factor fig. (5) shows that when air flow reaches the highest point which is 50 l/min, the skin friction will be at the highest point as well. the figure also shows that the slope of lines in the chart decreases when the air flow increases. this happens due to the increase of microbubbles which are injected. this leads to the decay of turbulence area at the boundary layer area. fig. 5, skin friction factor versus α conclusions  good results have been obtained with the present technique besides the economic limit.  increase air flow rate leads to increasing drag reduction.  the friction factor ripple attributed to change turbulence resulting reynolds number changed.  the maximum value of drag reduction is 25.11%.  nomenclature a: inside area of flow pipe dr: drag reduction cf: skin friction factor nre: reynolds number q,ql: liquid flow rate qair: air flow rate v: velocity f : friction factor greek symbols δpa :pressure drop after air injection δpb: pressure drop before air injection :ql/qa α specific gravity :ρ dynamic viscosity:µ references 1fabula a.g., hoyt, .j.w., crawford, h.h. turbulent-flow characteristics of dilute aqueous solutions of high polymers, bulletin, american physical society, vol. 8, 1963. p. 477. 2j. g. savins, “drag reductions characteristics of solutions of macromolecules in turbulent pipe flow,”society of petroleum engineers journal, vol. 4, p. 203, 1964. 3mc cormick me, bhattacharyya r (1973) drag reduction of a submersible hull by electrolysis. nav eng j 85:11–16. 4cl merkle and s deutsch, in “experimental fluid mechanics, lecture notes in engineering” (m gad-el-haq eds) vol.46, springerverlag, berlin, pp. 291 (1989). 5h. sayyaadi, m. nematollahi, “determination of optimum injection flow rate to achieve maximum microbubble drag reduction in ships; an experimental approach” scientia iranica b (2013) 20 (3), 535–541. 6nk madavan, cl merkle and s deutsch, trans. of the asme, 107, 370 (1985). 7roger kinsky, “applied fluid mechanics”,8th edition, mc grawhill, pp. 71-72, 119-123 (1983). 8bottural l., “friction factor correlations”,cryosoft,www.cryoso ft.com, feb.6 (1999). qair/ql c f 0.010 0.012 0.014 0.016 0.018 0.020 0.0 0.5 1.0 1.5 q air =30l/m in q air =40l/m in q air =50l/m in ijcpe vol.10 no.1 (march 2009) iraqi journal of chemical and petroleum engineering vol.10 no.1 (march2009) 9-16 issn: 1997-4884 nonlinear adaptive control of a ph process salam k. al-dawery * , hameed ali omran al-anbari and duraid fadhel ahmed * chemical engineering department college of engineering university of baghdad – iraq abstract in this paper a nonlinear adaptive control method is presented for a ph process, which is difficult to control due to the nonlinear and uncertainties. a theoretical and experimental investigation was conducted of the dynamic behavior of neutralization process in a continuous stirred tank reactor (cstr). the process control was implemented using different control strategies, velocity form of pi control and nonlinear adaptive control. through simulation studies it has been shown that the estimated parameters are in good agreement with the actual values and that the proposed adaptive controller has excellent tracking and regulation performance. introduction the regulations on the quality of industrial waste have become increasingly stringent in recent years. industrial waste must be neutralized before it discharged as effluent from the manufacturing plant, and must be maintained within stringent environmental limits. the control of ph, the subject of this study, fined important application in wastewater treatment and chemical industry. however, ph control is a difficult due to the following reasons: (i) the process is highly nonlinear dynamics (ii) waste streams frequently have multiple unidentified components, variable composition, and variable flow (iii) it is very sensitive to disturbances near the point of neutrality. thus, the control of ph process requires the application of advanced control techniques. a key difficulty seems to be the wide range of operating condition over which good control is required. use of a conventional, fixed gain, feedback controller tuned for the treatment plant waste will often provide an unstable or unsatisfactory result. this can prevent by application of adaptive control (1). the dynamics and control of ph in stirred tanks have been treated extensively in the literature. hoyle (2) gave some guidelines in the process design and choice of equipment for controlling the ph of plant. a classical analogue pid controller is the first method implemented for controlling ph. a feedforward controller based on the feed flowrate and/or feed ph was implemented on ph process control by shinskey (1973a). myron and shinskey (3) combined the feedforward controller together with nonlinear controller in order to calculate the required size of the manipulated variable. wright and kravaris (4) presented a novel technique for designing pi controller. the equivalent objective, being linear in states, yielded superior performance in comparison with fixed-term pi control. jacobs and hewkin (5) designed a modern control technology, in the form of an online digital computer using recently developed control algorithm. many different model based control methods have been proposed under different problem settings. among them are inline process-model based control, nonlinear inferential control, and nonlinear control using strong acid equivalent, etc. while different nonadaptive techniques have been attempted, many researchers to overcome the intrinsic uncertainties of the process model have also studied adaptive nonlinear control (6). gustafsson and waller (7) designed a nonlinear adaptive controller; they found it outperforms those of the conventional pid and linear adaptive controllers. lakshmi et al. (8) proposed an university of baghdad college of engineering iraqi journal of chemical and petroleum engineering nonlinear adaptive control of a ph process 10 ijcpe vol.10 no.1 (march 2009) adaptive internal model control technique; it may not work properly for more complex neutralization process. yoon et al. (9) presented an adaptive backstepping state feedback controller for a ph process with a proof on internal stability. in this paper, two methods were experimentally applied, first, the use of the computer to replace the conventional analogue pid controller in a typical single input single output ph control loop where there appeared to be scope for improving performance, secondly the use of an adaptive controller. theory velocity form the operation of an ideal pi controller is described by  ) 1 ( 0 edtekpp c  (1) in conventional control applications, a controller, whose output approximates the right side of equation (1), can be built through the use of pneumatic components or operational amplifiers, integrators, and summers. in computer-control applications a discrete equivalent to equation (1) is employed. in the development of algorithms that are based on z transforms we specify the nature of the response to be achieved, whereas in the digital equivalent to the pi controller we adjust the constants kc and ti so as to achieve a desired response (10). an alternative form for the pi and pid control algorithms is the so-called velocity form. in this form, one does not compute the actual value of the controller output signal at the nth sampling instant, but its change from the preceding period (11). to obtain the digital equivalent to the pi controller, the integral term of equation (1) is numerically approximated to give an expression for the output of the algorithm at sampling instant. thus        e t kekpkp i c  )()( 0 (2) p (k): controller output at nth sampling instant. po: steady state output of the control algorithm that gives zero error. e (k): error (set point – measurement) at the nth sampling instant. equation (2) is referred to as the “ position “ form of the control algorithm, since the actual controller output is computed. to derive an alternate form of the algorithm, the expression for controller output at the (k-1) th sampling instant was written as:        e t kekpkp i c  )1()1( 0 (3) then we subtract equation (3) from equation (2) to obtain        )()1()()1()( ke t kekekkpkp i c  (4) equation (4) is referred to as the velocity form of the pi algorithm, because it computes the incremental output instead of the actual output of the controller. the velocity form of the algorithm also provides some protection against reset windup, because it does not incorporate sums of error sequences (10). nonlinear adaptive control a nonlinear relation between reagent flow and measured ph distinguishes the ph control. if uniform damping is to be achieved in a highly nonlinear ph control loop, a complementary nonlinear control function must be used. the simplest form of this nonlinear function appears as a combination of three straight lines as shown in figure (1). both the widths of the deadband and the gain within it must be adjustable to match the particular process being encountered. as with the process titration curve, the controller gain is not simply the slope of the nonlinear function at a given point, but rather the slope of a line connecting that point with zero error. in mathematical terms, the gain gf can be represented by the following nonlinear function f (e) salam k. al-dawery, hameed ali omran al-anbari and duraid fadhel ahmed 11 de edf e ef g f )()(  (5) where e and f (e), the error input and its function expressed in the same units. the nonlinear function can be described as egbeef l  )()( (6) where b is the width of half the deadband and gl is the gain within the deadband. then the gf is lf g e be g    )( ( (7) the nonlinear function must be adjusted fit the particular process being controlled. in the absence of a titration curve, or when the buffering is variable, this becomes a trial and error procedure. with the deadband set at zero, a limit cycle will ordinarily ensure, even with a very wide proportional band. the width of the limit cycle is a guide of the deadband need not be quite as wide to stop the limit cycle. an unbuffered system will require the lowest available setting of gl. if gl is too low for a given process, however, it can actually promote a limit cycle exceeding the width of the deadband. adjustment of the proportional band should be made for fast recovery from upsets that drive the measurement outside of the deadband. if the proportional band is too narrow, an excursion outside the deadband on one side will produce enough corrective action to drive the measurement out the other side, thereby creating a limit cycle larger than the deadband, but the natural period. the nonlinear function described is symmetrical, and is therefore only useful for control in the neutral region. if control is desired at some other point, for example, ph=3, nonlinear compensation is desirable but it must be asymmetric. for a simple titration curve, it is possible to remove the high gain region from one side of the set point and adjust the deadband width so that its edge coincides with the knee of the curve (12). figure (1): the dead band width and gain in a nonlinear controller. experimental work description of the experimental equipment a simplified schematic diagram of the ph neutralization system is shown in figure (2). the process consists of an (base or acid) solution that prepared in a 100 liter feed tank in the base of the equipment, from which it is pumped via a variable area flow meter, and a hand-operated valve, into a stirred mixing vessel of approximately 3.318 liters capacity. the reagent (acid or base) is held in a 50 liter feed tank integral with feed tank, the whole being constructed in pvc. the reagent is pumped into the mixing vessel via a variable area flow meter, a hand valve, and a pneumatically operated control valve. a dip electrode and a ph transmitter/ indicator monitor the ph of the solution in the mixing vessel whose output is a current in the range 4-20 ma. this current is fed to a converter unit where converts it to 0-10 volts and then sends to the computer control system. a control signal output from computer control in the range 0-10 volts is fed to a converter unit where converts it to 4-20 ma. the signal supplied to a current/pressure (i/p) converter that in turn supplies an air pressure signal in the range 3-15 psig to operate the control valve nonlinear adaptive control of a ph process 12 ijcpe vol.10 no.1 (march 2009) description of the computer control system the computer control system requires a personal computer and an interface unit that consists of an analog to digital converter (adc) and a digital to analog converter (dac). this work has involved the use of ibm pc/386 personal computer that is used for process monitoring and control. the interface unit receives an analog signal from the converter unit and converts it to a digital signal through an adc then sends it to the computer. the output signal from the computer is loaded to the dac that converts it to an analog signal. then this signal is fed to a converter where coverts it to 4-20 ma. the hardware block diagram of the digital computer control system is shown in figure (3). experimental arrangement the application of the ph control was tested for three sets of effluent and reagent, these are 1. caustic soda (effluent) –hydrochloric acid (reagent). 2. ammonia (effluent) – hydrochloric acid (reagent). 3. acetic acid (effluent) – caustic soda (reagent). the runs of the experiment were carried out at various conditions (feed concentration, feed flowrate, set point change). using two different disturbances carried out the study of the dynamic behavior. first, the flowrate of acid stepped up from 0.5 lit. /min. to 0.7 lit. /min. and secondly the flowrate of base stepped down from 0.5 lit./min. to 0.2 lit./min. and stepped up to 0.5 lit./min.. to determine the controller settings, several disturbances were made and under all control methods. influent flow stepped down from 0.5 to 0.3 lit. /min. by using valve, ph set point stepped down from the neutral point to 5, and then after 7 minutes stepped back to 7 and ph set point stepped up from the 8.72 to 10, and then after 7 minutes stepped back to 8.72. figure (2) ph control system figure (3): hardware components of digital computer control system. salam k. al-dawery, hameed ali omran al-anbari and duraid fadhel ahmed 13 results and discussion in this section, the adaptive nonlinear controller presented in 2.2 is applied to the ph neutralization system. in order to ascertain the advantages offered by the adaptive nonlinear control strategy, experimental results are also presented for a pi controller and the non-adaptive version (velocity form) controller. the controllers are evaluated for setpoint changes and disturbances in effluent flowrate. open-loop behavior in this section, the steady state and dynamic open-loop behavior of the experimental ph system is investigated. open-loop responses for the effluent flowrate changes are shown in fig. (4) and fig. (5). fig. (4) shows the ph response to 40% increase in the effluent flow, which was changed from 0.5 to 0.7 lit. /min. fig. (5) shows the response on a pulse change in effluent flowrate from 0.5 to 0.2 and then 0.5 lit. /min.. faster responses were reported for high and low ph than for nearly neutral found a slower response in going from water to acid than in going from acid to water. response at ph 7 is very fast when a strong acid is neutralized by a strong base, or vice versa. at a total flowrate (fa+ fb) of 1 lit./min. a basic system apparent time constant of 221 second. and dead time of 4 sec. were obtained by using cohen & coon settings from dynamic experimental results. the theoretical dynamics would predict a basic time constant of 199 second and gain of the process (kp) equal to -2.17x 106 ph. min./mol . the approximate transfer function describing the system is first order with dead time, therefore: conventional control the performance of a conventional pi controller for effluent flowrate changes is shown in fig. (6). derivative action is not included in the controller because of the ph measurement time delay. it is clear from the results that a conventional, with fixed parameters controller is unsuitable for the control of a system with high nonlinear. velocity form of the pi control a digital computer has been interfaced to control the ph of effluent. it is programmed to implement feedback control. the velocity form presented in section 3.1 for setpoint change and effluent flowrate disturbance. the setpoint change performance of the velocity form controller is shown in fig. (8). the controller produces oscillatory control moves, which induce sustained ph oscillation. the flowrate disturbance is shown in fig. (7). it appears that the oscillation result from instability mechanism (i.e. the system is unstable at this operating point) because the ph and effluent flowrate are near their steady state values when the oscillation begin, some of the improvement in performance from the pi conventional controller. for all the neutralization system the strong base/strong acid, weak acid/strong base and weak base/strong acid solutions, the best controller gain and reset time are found and presented in table (1). nonlinear adaptive control the adaptive nonlinear controllers for setpoint change and effluent disturbance are shown in fig. (9) and fig. (10). the small ph oscillations observed in the response of the adaptive controller for these disturbances are caused mainly by the high process gain and process noise. the adaptive controller yields slightly improved ph responses as compared to the non-adaptive controller for the disturbances. the ph responses in fig. (9) and fig. (10) demonstrate the adaptive controller is able to provide good control for a wide range of conditions. the best pi controller settings (gain and reset time), the deadband width (b) and the adaptation gain are found and presented in table (2). figure (4): comparison between the simulated and experimental ph responses for pulse change in base flow rate, naoh-hcl.   )8( 1199    s ek f ph sg st p a d nonlinear adaptive control of a ph process 14 ijcpe vol.10 no.1 (march 2009) figure (5): comparison between the simulated and experimental ph responses for pulse change in base flowrate, naoh-hcl. figure (6): process response under pi (conventional) method, flowrate stepped (naoh/hcl). figure (7): comparison between the simulated and experimental ph responses for step in base flowrate reduced from 0.5 to 0.3 lit./min. under velocity form of pi control, naoh-hcl. figure (8): comparison between the simulated and experimental ph responses for ph set point stepped down from 7 to 5 and then stepped back under velocity form of pi control, naoh-hcl. figure (9): comparison between the simulated and experimental ph responses for ph set point stepped down from 7 to 5 and then stepped back under nonlinear adaptive control, naoh-hcl. figure (10): comparison between the simulated and experimental ph responses for step in base flowrate reduce from 0.5 to 0.3 lit./min. under nonlinear adaptive control, naoh-hcl. salam k. al-dawery, hameed ali omran al-anbari and duraid fadhel ahmed 15 table 1: the pi controller settings for velocity form of pi control. table 2:the pi controller settings for nonlinear adaptive control conclusions this paper has presented the improvement of a ph control process by using two methods. the velocity form and adaptive versions of the controller were compared to a conventional pi controller on a bench scale ph neutralization system, which exhibits significant nonlinear and time varying behavior. it is concluded that a digital computer can give substantially improved control of ph because of the ease which it can process information and exploit it by implementing feedback control. numerical simulations demonstrated that the parameter as well as the state estimates are in good agreement with the actual values and that the proposed adaptive controller has excellent tracking and regulation performance under various changes in influent streams of the ph process. the adaptive method provides better control for the neutralization process by reducing the size of the ph deviation to process disturbances. a reduction in the oscillation level around the neutral point was also achieved. references 1. ylostalo, t., hyotyniemi, h. and jutile, p., "comparison of adaptive control methods in ph process control" isa research triangle part c, north caroline, 2000. 2. hoyle, d. l., "designing for ph control", chem. eng., vol. 48, no. 24,p. 121, (1976). 3. orava, p. j., and niemi, a. j., "state model and stability analysis of a ph control process", int. j. control, vol. 20, no. 4,p. 557, (1974). 4. wright, r. a. and kravaris, c., “nonlinear ph control in a cstr “, american control conference proceeding, p.21, sep. 1986. 5. jacobs, m. a., hewkin, m. a., "online computer control of ph in an industrial process", iee proc., vol. 127, pt. d, no. 4,p. 161, (1980). 6. tae chul lee and dae ryook yang, "indirect adaptive backstepping control of a ph neutralization", ind. eng. chem. res., vol. 40, p. 4102, (2001). 7. gustafsson, t. k., waller, k. v., "dynamic modeling and reaction invariant control of ph ", chem., eng., sci., vol. 38, p. 389, (1983). 8. patwardhan, r. s., lakshminarayanan, s. and shah, s. l., “nonlinear model predictive control using pls based hammerstein and wiener models”, presented at the a. i. ch. e. meeting, la, session 217,nov., (1997). 9. yoon, s. s., yoon, t. w., yang, d. r. and kang, t. s., “indirect adaptive nonlinear control of a ph process”, ifac 99, (china), (1999), pp. 139. 10. pradeep, b. deshpande, and raymond, h. ash, ” elements of computer process control”, (1981). time of integral action τi, min. gain kc lit./min./ph system 0.5 0.03 naoh/hcl 0.5 0.05 hac/naoh 0.5 0.05 nh3/hcl system set point band kc gain within band time of integral action τi b1 b2 naoh/hcl 7 10 4 1 2 2 1 1 1 0.05 0.05 0.05 0.5 0.5 0.5 hac/naoh 7 10 4 1 2 2 1 1 1 0.06 0.06 0.06 0.5 0.5 0.5 nh3/hcl 7 10 4 1 2 2 1 1 1 0.06 0.06 0.06 0.5 0.5 0.5 nonlinear adaptive control of a ph process 16 ijcpe vol.10 no.1 (march 2009) 11. george, stephanopoulos, “chemical process control an introduction to theory and practice”, prentice/hall international, inc., (1984). 12. shinskey, f. g., “ph and pion control in process and waste stream”, john wiley & sons, (1973). iraqi journal of chemical and petroleum engineering vol.16 no.1 (march 2015) 7178 issn: 1997-4884 formation evaluation for nasiriyah oil field based on the nonconventional techniques *ayad a. alhaleem, antwan m. avedisian,and haider alwan flayeh *petroleum engineering, university of baghdad abstract the unconventional techniques called “the quick look techniques”, have been developed to present well log data calculations, so that they may be scanned easily to identify the zones that warrant a more detailed analysis, these techniques have been generated by service companies at the well site which are among the useful, they provide the elements of information needed for making decisions quickly when time is of essence . the techniques used in this paper are:  apparent resistivity rwa technique.  rxo /rt method. the above two methods had been used to evaluate nasiriyah oil field formations (well-ns-3) to discover the hydrocarbon bearing formations. a computer program had used to represent cpi results for the two mentioned methods, the results of interpretation indicate to hydrocarbon zones in. key words: nasiriyah oil field, quick look techniques. introduction nasiriyah structure was discovered in 1975 through a seismic investigations covered partially the southern part of iraq by iraqi national oil company (inoc).this structure had clearly appeared at that time as a longitudinal anticline [1] .five oil wells had been drilled to sulaiy formation during the period 1978-1987. it is considered as giant oil field in southern part of iraq and located in nasiriyah area.nasiriyah oil field is located in the nw-se oriented mesopotamian zone extending across the alluvial plains of the euphratestigris valleys. the mesopotamian zone is characterized by quaternary molasses and absence of surface relieves of folds [2]. apparent resistivity rwa technique the rwa techniques also called the quick look techniques which is useful for detections of hydrocarbon pay zones and estimation of water saturation and formation water resistivity, rwa define as[3][4]: rwa = rt / f ……………… (1) where: -rtis the true formation resistivity from well logs, and f = 0.62 ø -0.25 which is humble equation * . iraqi journal of chemical and petroleum engineering university of baghdad college of engineering formation evaluation for nasiriyah oil field based on the non-conventional techniques 72 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net *: humble equation has been used in sandstone and carbonate formations, which are the main lithological column of the studied area. porosity had been calculated from sonic or neutron logs, in clean water bearing zones, the reading of deep resistivity tool will approximate to ro and because: ro=f. rw…………………….. (2) so as: rwa =rt / f = ro / f = rw……… (3) it follow that, in hydrocarbon zones rt>ro so that rwa>rw. simple rearrangements to archie equation (1) and substitute of equation (3) will results in: swa= (rw/ rwa) 1/2 .…… …. (4) the water saturation is related to as apparent due to this method is unconventional one, in practice rwa may be calculated or read it directly from well logs in the section of interest, rw also may be calculated from sp or from formation water analysis. if rwa/ rw calculated the hydrocarbon zones can be defined according to equation (4). restrictions of apparent resistivity rwa technique the rwa technique is still applicable when water resistivity rw is unknown. however two conditions must be fulfilled [3][4]: 1water zones must be present in the section evaluated. 2no abrupt salinity changes can occur over the section of interest so that the rw can be considered as constant, therefore the (rwa) min in water bearing zones is then selected to define rw. abnormally high rwa values can be displayed by zones other than hydrocarbon. relatively highresistivity shale will display a high rwa values. shale zones can be distinguished easily by shale indicators such as gamma ray and sp logs. cycle skipping of the sonic log will also cause high rwa values [3][5]. the rxo/rt method to economically establish the existence of producible hydrocarbon reservoirs (oil & gas), well logs contain key information about the formation drilled in different petrophysical measurements, among these measurements are (sp and resistivity) [3]. this method was introduced by dumanoir et al. [6] for well site interpretation. this technique involves computing log (rxo/rt)from either the rll8/rild or the rsfl/rild ratio and recording it as a comparative curve with the sp. separation between the properly scaled (rxo/rt)curve and the sp provide a quicklook location for the producible hydrocarbons [3]. the rxo/rt method is based on the calculation of the parameter (esp)ql derived from the ratio rxo/rt,so [1][6] : (esp)ql= -k log (rxo/rt) ………… 6 because rxo= f .rmf / sxo n and rt= f. rw / sw n then: rxo/rt= (sw/sxo) n (rmf / rw) then equation (6) becomes: (esp)ql = -k log{(sw/sxo) n (rmf / rw)} …… 7 after re-arrange the above equation, then it will became; (esp)ql= -k{log(rmf / rw) + log(sw/sxo) n } ….. 8 ayad a. alhaleem, antwan m. avedisian,and haider alwan flayeh -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 73 fig. 1, swa results from mishrif to zubair formations formation evaluation for nasiriyah oil field based on the non-conventional techniques 74 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net fig. 2, swa results from zubair to sulaiy formations ayad a. alhaleem, antwan m. avedisian,and haider alwan flayeh -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 75 the calculation of (rxo/rt)does not require knowledge of porosity, formation factor, or rw. the technique is most suitable for cases where porosity is not available or cannot be determine accurately owing to complex lithology, or when f-ø relationships are in appropriate [7]. the main advantage of this method is to[7] (provide a means for locating hydrocarbons), because the proven presence of hydrocarbons does not necessarily mean commercial production, this method is an appropriate companion to techniques that only indicate hydrocarbon presence, such as the previous method. but the measured esp is (esp) log can be approximated by the term {-k log (rmf / rw)}; therefore: (esp)ql= (esp)log – k log(sw/sxo)n … 9 in water bearing zones or in the zones with no movable hydrocarbons sw= sxo ,then (esp)ql= (esp)log and the separation will be negligible ,otherwise in movable hydrocarbon zones the (esp)ql will separate from (esp)log and (esp)ql< (esp)log this is due to (sxo>sw) and log(sw/sxo) < 0, the results are shown in the figures (3) and (4) respectively. finally it is more important to know that the rxo / rt method is applicable to fresh mud, (rxo>rt) in formations where invasion falls within the limits demanded by the (rxo/rt) computation [7]. evaluation of the unconventional methods the results of these methods indicate to presence of hydrocarbons in maudud, nahar umar and zubair formations respectively in addition to the conventional reservoirs (mishrif and yammama), table (1) show the results of these methods in nasiriyah oil field which are contiguity to the results of dst and flow test. table (1) hydrocarbon zones by nonconventional methods conclusions the detected oil zones in this study are compared with the results of conventional interpretation with actual archies’ parameters (a, m and n ),dst, flow test and daily drilling reports ,from which we can be sure that most zones that interpreted as oil are correct because of convergence between the different interpretation methods and the provided reports data. n fm. rwamethod sp(ql) top botto m top bottom 1 mishrif 2006 .8 2026 2007.4 2019.5 2029 2085 2026 2074 2 maudud 2265 .1 2268.4 2281 2289 2296 2304 2321 2323 2319 2322 3 nahrum r 2416 .1 2422.4 2414.3 2422.8 2505 2517 4 zubair 2937.8 2940.5 2984 2988.7 5 yamma ma 3185 .7 3218.2 3184.2 3221.5 3227 .5 3238 3248.4 3268 334 2 3363 3280 3285 3326 3333 3358 3363 formation evaluation for nasiriyah oil field based on the non-conventional techniques 76 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net fig. 3, rxo/rt method results from mishrif to zubair formations ayad a. alhaleem, antwan m. avedisian,and haider alwan flayeh -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 77 fig.4, rxo/rt method results from zubair to sulaiy formations formation evaluation for nasiriyah oil field based on the non-conventional techniques 78 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net references 1. national iraqi oil company, 1981, primary geological and appraisal study about mishrif, ratawi and yammama formations 2. eni company “nasiriyah oil fieldintegrated reservoir study updating” 2007. 3. zakibassiouni, 1994 “theory, measurement and interpretation of well logs”, spe textbook series, vol-4, 241-254. 4. antwan m. avedisian, 1988 “well log analysis”, 456-459. 5. russell w. spears1, frank shray2, scott jacobsen3, mark c. bowers1, wayne f. 6. nicosia11 exxonmobil production company, houston, texas2 schlumberger, lagos, nigeria3 schlumberger, houston, texas, may 25-28, 2008 “where quicklook petrophysics goes wrong: a case study in a mature south texas gas field”, spawla,edinburgh, scotland, 35. 7. schlumberger, “log interpretation – principles/applications”, 1989.chapter 8, 8-10. 8. m.p. tixire, r.p. alger, and d.r .tanguy, may-1960, ''new developments in induction & sonic logging'' journal petroleum technology, 3-6. ijcpe vol.10 no.2 (june 2009) iraqi journal of chemical and petroleum engineering vol.10 no.2 ( june 2009) 35-42 issn: 1997-4884 oxidation of phenolic wastewater by fenton's reagent ibtihage faisal chemical engineering department college of engineering university of baghdad – iraq abstract phenol oxidation by fenton's reagent (h2o2 + fe+2) in aqueous solution has been studied for the purpose of learning more about the reactions involved and the extent of the oxidation process, under various operating conditions. an initial phenol concentration of 100 mg/l was used as representative of a phenolic industrial wastewater. working temperature of 25c was tested, and initial ph was set at 5.6 . the h2o2 and the fe+2 doses were varied in the range of (h2o2/fe+2/phenol = 3/0.25/1 to 5/0.5/1). keeping the stirring speed of 200 rpm. the results exhibit that the highest phenol conversion (100%) was obtained under (h2o/fe+2/phenol ratio of 5/0.5/1) at about 180 min. the study has indicated that fenton's oxidation is first order with respect to the phenol concentration and the rate constant k, was found to be 0.0325s-1 . introduction increasing concern about environmental and health risks demand a more rigorous control of industrial wastewater, promoting the development and implementation of new treatment technologies capable to deal with toxic pollutants resistant to the widely established conventional methods. among this type of pollutants, phenol and phenolic compounds have attracted much attention in the last two decades. this interest arises from their relative frequency in the aqueous effluent of the chemical industry. moreover, phenol is considered to be an intermediate in the oxidation pathway of high molecular weight aromatic hydrocarbons, and thus it is frequently used as a model compound for advanced wastewater studies(1). advanced oxidation processes (aops) are an interesting treatment option for this type of wastewaters, because of their great potential to oxidize, partially or totally, numerous organic compounds(2-4). these processes are based on the generation of hydroxyl radicals (oh). this species is a more powerful oxidant (e 2.8v) than the chemical reagents commonly used for this purpose, such as ozone (e 2.0v) or h2o2 (e 1.8v). rate constants in aops for organic compounds are several orders of magnitude higher than those reported for others processes such as ozonation(5). due to its high reactivity, the hydroxyl radical is very unstable and must be continuously produced in situ by means of chemical or photochemical reactions(3). the main methods to generate this radical consist of the use of o3 at elevated ph ( 8.5), o3/h2o , o3/catalyst , fenton's reagent (fe+2/h2o2) , o3/uv , h2o2/uv , o3/h2o3/uv , photo-fenton/fenton-like systems, and photocatalytic oxidation (uv/tio2)(6). one of the most effective aops consist of the use of fenton's reagent, a combination of h2o2 and fe+2. in this process, h2o2 decomposes catalytically by means of fe+2 at acid ph, giving rise to hydroxyl radicals. (1) ohohfeohfe 3h 22 2     university of baghdad college of engineering iraqi journal of chemical and petroleum engineering oxidation of phenolic wastewater by fenton's reagent 2 ijcpe vol.10 no.2 (june 2009) the application of fenton's reagent as an oxidant for wastewater treatment is attractive, in principle, due to the fact that fe is a widely available and nontoxic element, and hydrogen peroxide is easy to handle and the excess decomposes to environmentally safe products(7). among the advantages of fenton's process relative to other oxidation techniques are the simplicity of equipment and the mild operation conditions (atmospheric pressure and room temperature); mainly for these reasons fenton's process has been regarded as the most economical alternative(8). numerous authors have studied the mechanism of oxidation of organic compounds by fenton's reagent. the number of reactions is high, and the schemes of reaction are generally complex. in an overall view, the process can be represented by the following reactions(9) : (2) t esint ermediareact ion ohcod 32 fe/fe 22    (3) salt s inorganic ohcooh t esint ermediareact ion 22 fe/fe 22 32     the oxidation of the substrate completely to co2 becomes, in general, uneconomical due to high h2o2 consumption. thus, this process has been mostly proposed as a pretreatment to reduce the effluent toxicity to safe levels for further biological treatment(10). for this reason, it is necessary to study the reaction pathway in depth, as the toxicity of some intermediate can be higher than that of the initial compound. this is the case in the oxidation of phenol, where hydroquinone and pbenzoquinone are formed, the toxicities of which are several orders of magnitude higher than that of phenol itself(11). due to the complexity of the whole process, the various reaction schemes found in the literature refer to partial studies, with specific objectives. for some of them, the aim was to detect the reaction intermediates, whereas others studied the influence of these products in the evolution of the process. the aim of the present work is to study the oxidation of phenol with fenton's reagent. first, the intermediates from phenol oxidation were identified, using different concentration of catalyst (fe+2) and oxidant (h2o2). finally a kinetic study was carried out, to obtain the kinetic rate constant for the oxidation of phenol. experimental work experiments were carried out in 100 ml glass batch reactor shaken in a constant temperature batch (25c) at an equivalent stirring velocity around 200 rpm for 4 hour. the reaction volume was 50 ml, and the reactants were added simultaneously at the beginning of each run. the starting phenol concentration was 100 mg/l and 300 to 500 mg/l of h2o2 (which corresponds to the stoichiometric amount of h2o2 necessary to oxidize phenol to co2 and h2o. the fe+2 dose was varied between 25 and 50 mg/l. the sample was analyzed after the reaction. phenol and aromatic intermediates identified and quantified by means of uv-spectrophoto-meter and high-performance liquid chromatography. results and discussion evolution of phenol oxidation: it is obvious that the effect of h2o2/fe+2/phenol ratio is the predominate factor in oxidation of phenol. keeping other factors constant (ph=5.6, temperature = 25c, and stirring speed = 200 rpm). fig. 1 shows the conversion of phenol versus time for different ratios of h2o2/fe+2/phenol. the total phenol oxidation was obtained with 5/0.5/1 ratio at about 180 min. fig. 1 effect of h2o2/fe+2/phenol ratio on the phenol oxidation. ibtihage faisal 3 ijcpe vol.10 no.2 (june 2009) fenton's reagent of hydrogen peroxide and an iron catalyst which will rapidly oxidize phenol over wide rang of concentration and temperatures. iron is one of the most common metals that have special oxygen transfer properties which improve the utility of hydrogen peroxide. this iron-catalyzed hydrogen peroxide is (fe+2), hydroperoxyl radicals (ho), and/or superoxide radicals (  2o ) according to the following reaction: (4) hoohfeohfe 3 22 2    (5) hoohohho 22222    (6) hoho 22    super oxide radicals are dominating at neutral ph and hydrogen peroxide also may contribute to hydroxyl radical formation by the following overall equation: (7) hoohoooh 2222    evolution of intermediate compounds: figures (2) and (3) summarize the evolution of the oxidation reaction of phenol with fenton's reagent under the experimental conditions (h2o2/fe+2/phenol of 5/0.5/1, ph = 5.6 , temperature = 25c , and stirring speed = 200 rpm). as can be seen, under these experimental conditions close to 80% of phenol is converted in about 30 min , giving rise to dihydroxybenzenes upon hydroxylation of the aromatic ring. catechol is main primary oxidation product, indicating that hydroxylation takes place predominantly in the ortho position. the peak concentration of hydroquinone was about one-tenth that of catechol. ring-opening of the aromatic intermediates leads to the formation of organic acids. as a result, a ph decrease takes place, although it remained always within the optimum range, above 2. these compounds are intermediates and/or final oxidation products. maleic, acetic, and formic acids were the earlier and more abundant products of the acid formation stage. oxalic acid was appearing at a lower rate, although it reached a high relative concentration as the oxidation reaction proceeded. fig. 2 evolution of aromatic compounds identified in phenol oxidation with fenton's reagent. fig. 3 evolution of organic acids identified in phenol oxidation with fenton's reagent. figure (4) summarizes the scheme of reaction proposed for phenol oxidation with fenton's reagent, according to our results. ijcpe vol.10 no.2 (june 2009) o oh h h h o o oh oh h h o h o oh o oh o oh oh oh oh o o oh oho o 1, 2 1 1 h2o + co 2 acetic acid maleic acid glyoxylic acid phenol catecholo-benzoquinone p-benzoquinone hydroquinone 1 , 2 1 , 2 1 , 2 1 1 undesired route desired route oxalic acid c oh h o 1 h2o + co 2 2, 3 formic acid fig. (4) : proposed reaction scheme in this work. reaction steps include: 1oxidation 2c-c bond cleavage. 3transfer hydrogenation. conclusions this study indicated that the phenol in aqueous solutions can be oxidized by fenton's reagent. the results showed that the degree of phenol oxidation depends to large extent on h2o2/fe+2/phenol ratio. during destruction by h2o2 in fenton's reagent system, phenol undergoes a transformation through a variety of chemical intermediates, leading in the production of co2 and h2o which is relatively harmless by product. references 1. ding, z.; aki, s.; abraham, m. a. catalytic supercritical water oxidation; phenol conversion and product selectivity. environ. sci. technol. 29(11), 2748-2753 (1995). 2. bigda, r.j. consider fenton's chemistry wastewater treatment. chem. eng. prog. 91(12), 62-66 (1995). 3. esplugas, s.; gimenez, j.; contreras, s.; pascual, e.; rodriguez., m. comparison of different advanced oxidation processes for phenol degradation. water res. 36(4), 1034-1042 (2002). 4. neyens, e.; baeyens, j. a review of classic fenton's peroxidation as an advanced oxidation technique. j. hazard. mater. 98, 33-50 (2003). 5. benitez, f. j.; beltran-heredia, j.; acero, j. l.; rubio, f. j. oxidation of several chlorophenolic derivatives by uv irradiation and hydroxyl radicals. j. chem. technol. biotechnol. 76(3), 312-320 (2001). 6. manter, r. advanced oxidation processes. current status and propects. proc. est. acad. sci., chem. 50, 59-80 (2001). 7. jones, c. w. applications of hydrogen peroxide and derivatives; royal society of chemistry : cambridge, u.k., 1999. 8. perez, m.; torrades, f.; garcia-hortal, j. a.; domenech, x.; peral j. removal of organic contaminants in paper pulp treatment effluents under fenton and photo-fenton conditions. appl. catal., b36(1), 63-74 (2002). 9. al-hayek, n.; eymery, j. p.; dore, m. catalytic oxidation of phenols with hydrogen peroxide. water res. 19(5), 657-666 (1985). 10. andreozzi, r.; caprio, v.; insola, a.; marotta, r. advanced oxidation processes (aop) for water purification and recovery. catal. today 53(1), 51-59 (1999). 11. santos, a.; yustos, p.; quintanilla, a.; garia-ochoa, f.; casas, j. a.; rodrignez, j. j. evolution of toxicity upon wet catalytic oxidation of phenol. environ. sci. technol. 38, 133-138, (2004). iraqi journal of chemical and petroleum engineering vol.16 no.3 (september 2015) 3544 issn: 1997-4884 correlation of penetration rate with drilling parameters for an iraqi field using mud logging data hassan abdul hadi university of baghdad, college of engineering, petroleum dept. abstract this paper provides an attempt for modeling rate of penetration (rop) for an iraqi oil field with aid of mud logging data. data of umm radhuma formation was selected for this modeling. these data include weight on bit, rotary speed, flow rate and mud density. a statistical approach was applied on these data for improving rate of penetration modeling. as result, an empirical linear rop model has been developed with good fitness when compared with actual data. also, a nonlinear regression analysis of different forms was attempted, and the results showed that the power model has good predicting capability with respect to other forms. key words: operation, rate of penetration (rop),modeling introduction during the last decades, the drilling engineers have been concerned extensively on prediction of drilling rate. this step is necessary since it help in the process of selection of drilling parameters (drilling optimization), which is important to decrease drilling cost per foot [1, 2]. it is well known that penetration rate is affected by controllable and uncontrollable factors. the controllable factors included weight on bit, rotary speed, bit type, mud properties, and hydraulics. while the formation characteristics is one of the uncontrollable factors that had significant effect on penetration rate [3]. unfortunately, there is no comprehensive mathematical drilling model that related the drilling rate and different drilling parameters. the primary reason for that is the large number of factors influencing the drilling rate, and due complexity and nonlinearity of relationship of these factors to each other and to drilling rate[4]. however, experts have put forward some suggestions to address this issue. they have succeeded to model the effects of different drilling parameters involving drilling rate as mathematical functions. bourgoyne and young is one of these model that is widely in practice [5]. rate of penetration modeling is recognized as a tool which can be used to reduce drilling costs by assisting bit selection and drilling optimization. there are many rates of penetration models available in drilling operations. but these models have two major problems. firstly, these models are derived under specific conditions, particularly from laboratory controlled experiments which are limited by the differences between the experimental and field data conditions. secondly, the iraqi journal of chemical and petroleum engineering university of baghdad college of engineering correlation of penetration rate with drilling parameters for an iraqi field using mud logging data 36 ijcpe vol.16 no.3 (sept. 2015) -available online at: www.iasj.net models derived from field data have lacked a detailed and systematic analysis of bit run data tacking into account the particular conditions of the bit run. the lack of the availability of a comprehensive computerized data base has also slowed down progress in rop modeling [6]. today, a mud log provides foot-byfoot data base which assists in modeling of rop accurately. these data includes, wob, rpm, his etc., and electric wireline logs, such as δt, gamma ray, resistivity and caliper logs. this data base provides an opportunity for rop modeling taking into different parameters which permits the modeling process more accuracy [7]. raw logging data the raw mud logging data were recorded for al zubair oil field. this field is located in south iraq, basrah city. the sequence of formations in this field are upper faris,tenoma, sheransh, umm radhuma respectively. umm radhuma formation is predominantly limestone .its considered the thickest formation in this sequence, about450 m, which made it a good selection for developing correlation. figs. (1), (2), and (3) shows the measurements interval feet by feet for rop, wob, and rpm with depth for this formation. these figures illustrate the difficulties of evaluating the relationship between rop and wob, rpm due to high fluctuation in these dataset. fig.1, raw rop versus depth data hassan abdul hadi -available online at: www.iasj.net ijcpe vol.16 no.3 (sept. 2015) 37 fig.2, raw wob versus depth data fig.3, raw rpm versus depth data correlation of penetration rate with drilling parameters for an iraqi field using mud logging data 38 ijcpe vol.16 no.3 (sept. 2015) -available online at: www.iasj.net penetration rate modeling statistical software called "spss" was used to perform various statistical analysis for modeling penetration rate with other drilling parameters. the raw data for umm radhuma formation was extracted from mud log data of well zb-232.as first step, a linear regression model was attempted for the modeling. table (1) shows the main drilling parameters that used in regression analysis and some statistical analysis for each parameter entered in the modeling. the rop is dependent variable, while the wob, rpm, mw, and q are the independent variables. table 1, statistical analysis of drilling parameters n range minimum mean std. deviation variance statistic statistic statistic statistic std. error statistic statistic rop 2251 395.41 1.00 17.3373 .27307 12.95550 167.845 wob 2251 27.03 .01 14.0190 .16803 7.97226 63.557 rpm 2251 79 73 119.33 .226 10.721 114.948 mw 2251 .05 1.10 1.1239 .00052 .02458 .001 q 2251 1696 1508 3023.55 1.945 92.267 8513.115 valid n (listwise) 2251 table(2) provides the analysis of variance for the data of the model. each items of this analysis can be defined by the following equations: ssr= … (1) sse = … (2) msr=ssr/k … (3) mse=sse/n-k-1 … (4) f=msr/mse … (5) where: ssr=sum of square regression sse=sum of square error(residual) mse= mean of sum error msr=mean of sum regression k=no.of parameters n= no. of points yi=actual value ῡ=mean value ỹ=predictive value df=degree of freedom table 2, analysis of variance of the liner model model sum of squares df mean square f sig. 1 regression 74872.621 4 18718.155 138.851 .000 b residual 302778.652 2246 134.808 total 377651.273 2250 table 3, values of coefficients of linear model model unstandardized coefficients standardized coefficients t sig. b std. error beta 1 (constant) -105.34617.467 -6.031.000 wob -.799.034 -.491-23.471.000 rpm .049 .025 .040 1.939 .053 mw 125.132 11.939 .237 10.481 .000 q -.004.003 -.030-1.512.131 hassan abdul hadi -available online at: www.iasj.net ijcpe vol.16 no.3 (sept. 2015) 39 table 4, model summery model r r square adjusted r square std. error of the estimate change statistics r square change f change df1 df2 sig. f change 1 .445 a .198 .197 11.61068 .198 138.851 4 2246 .000 fig.4, fitted and actual rop with depth before improving according to these statistical analysis of the interest data , the values of coefficients of this linear model are shown in the table(3).table (4) shows a weak strength of this relationship between rop and the other parameters since the value of square correlation coefficient is 0.197. fig. (4) displays the actual and fitted rate of penetration values as functions of depth for this data set. improving data quality in order to obtain more representative relationship between rop and its related variables, the quality of logging data for rop modeling must be improved by the following means: a. exclusion of outliers outlier may defined as the value that are far from the middle of distribution. in statistics language, any points that are beyond the outer fences are considered as outliers. thus, the statics software spss performs this exclusion process for logging data and detected the outliers for each parameter included in the modeling(rop,wob,rpm,q ,mw) as shown in figs.(5),(6),(7),(8),and(9). as result of this process,32.5% of the variation in the data was obtained by the model(r 2 =0.325) as shown by the fig.(10). 0 5 10 15 20 25 30 35 40 45 50 1 7 13 19 25 31 37 43 49 55 61 67 73 79 85 91 97 103 109 115 121 127 133 139 145 151 157 163 depth(ft) r o p (f t/ h r) correlation of penetration rate with drilling parameters for an iraqi field using mud logging data 40 ijcpe vol.16 no.3 (sept. 2015) -available online at: www.iasj.net fig.5, outliers of rop data fig.6, outliers of wob data fig.7, outliers of rpm data fig.8, outliers of flow rate data fig.9, outliers of mud weight data fig.10, predicted rop after removing outliers hassan abdul hadi -available online at: www.iasj.net ijcpe vol.16 no.3 (sept. 2015) 41 table 5, groups of modeling data t data size depth rop wob rpm density flow rate 1 8 1042.03 21.80 2.50 107.55 1.11 3015.21 2 42 1047.97 23.20 3.57 116.89 1.11 3015.05 3 17 1037.22 23.55 4.44 117.64 1.10 3015.01 4 28 1049.39 23.50 5.50 117.00 1.11 3015.18 5 29 1000.40 26.02 6.60 121.46 1.11 3015.34 6 33 1090.08 25.87 7.51 123.40 1.12 3015.29 7 23 1091.06 25.41 8.53 121.69 1.12 3015.39 8 48 1100.38 23.63 9.52 124.00 1.12 3015.68 9 42 1114.43 24.75 10.46 120.91 1.13 3015.25 10 45 1104.07 22.91 11.56 121.38 1.13 3015.40 11 49 1088.77 23.02 12.52 125.16 1.12 3015.68 12 66 1110.39 23.17 13.50 121.36 1.13 3015.45 13 47 1104.31 18.85 14.46 120.19 1.12 3015.26 14 117 1128.27 19.62 16.12 120.20 1.13 3015.26 15 73 1117.76 17.33 17.59 121.26 1.13 3015.30 16 76 1145.35 17.29 18.53 120.55 1.14 3015.20 17 45 1114.25 13.22 19.46 121.11 1.13 3015.30 18 53 1104.27 10.85 20.54 120.62 1.12 3015.40 19 57 1089.62 7.60 21.57 122.90 1.12 3015.50 20 64 1068.00 5.63 22.39 122.01 1.11 3015.69 21 17 1073.22 2.40 24.49 121.97 1.10 3015.37 22 9 1076.98 1.83 25.26 125.03 1.10 3015.91 23 4 1051.90 2.01 26.04 122.81 1.10 3015.00 table 6, descriptive statistics for grouped data n range minimu m maximu m mean std. deviation statistic statistic statistic statistic statistic std. error statistic depth 23 144.95 1000.40 1145.35 1084.7885 7.15576 34.31784 rop 23 24.19 1.83 26.02 17.5411 1.73989 8.34421 wob 23 23.54 2.50 26.04 14.0278 1.53514 7.36229 rpm 23 17.61 107.55 125.16 120.7425 .74842 3.58928 mw 23 .04 1.10 1.14 1.1166 .00227 .01089 q 23 .91 3015.00 3015.91 3015.3529 .04700 .22538 valid n (listwise) 23 correlation of penetration rate with drilling parameters for an iraqi field using mud logging data 42 ijcpe vol.16 no.3 (sept. 2015) -available online at: www.iasj.net b. grouping the data after removing the outliers, the logging data that were used for rate of penetration modeling will divided into number of groups. this approach for increasing the size of grouped data was proved statistically. with the aid of spss software, the logging data were grouped into 23 groups for each variable as shown in table(5). other statistics analysis of grouped data is shown in table (6). c. regression of grouping data as a final step, a linear regression analysis of logging grouped data was conducted to establish general model that relating drilling rate with drilling variables. table (7) summarizes the values of coefficients, while tables (8) and (9) provide other statistical analysis of this regression modeling. the final form of this model will be: rop=20902.003-1.059wob+ 1.11rpm+315.9mw+ 2.419q… (6) table 7, coefficients values of linear model model 95% confidence interval upper bound 1constant wob rpm mw q 20290.003 -1.059 1.11 315.902 2.419 as it was noticed from the above tables, a better relationship was obtained after processing logging data(r 2 =0.978) compared to the relationship before improving the interested log data. figure(10) also shows clearly very good correspondence between the measured and the calculated values of rop from eq. (6). table 8, linear model summery model r r square adjusted r square std.error of the estimate 1 0.989 0.978 0.972 1.3592 table 9, analysis of variance of the linear model model sum of square df mean square f 1 regression residual total 1173.423 25.866 1199.288 4 14 18 293.356 1.848 158.782 hassan abdul hadi -available online at: www.iasj.net ijcpe vol.16 no.3 (sept. 2015) 43 fig.10, actual and fitted rop table 10, nonlinear parameters estimation (case1) parameter estimate std. error 95% confidence interval lower bound upper bound a 3.841 5.928 -8.79516.477 b .436 .543 -.7221.594 c .001 .000 .001 .001 d -3.694.000 -3.694-3.694 e .001 .000 .001 .001 f .892 .000 .892 .892 g .542 .000 .542 .542 h -2.668213062466.597 -454131900.271454131894.935 table 11, nonlinear parameters estimation (case2) parameter estimate std. error 95% confidence interval lower bound upper bound a -10.7922.576 -16.183-5.401 b 18.614 55.137 -96.789134.017 c 17.298 127.173 -248.879283.474 d -5.86332.434 -73.74862.021 d. non linear regression a nonlinear regression analysis was also conducted on the logging grouping data for comparison purpose. in the first case a power model was attempted, and good fitness model was obtained (r 2 =0.91).table (10) provided the values of coefficients of this power model which has the following equation. correlation of penetration rate with drilling parameters for an iraqi field using mud logging data 44 ijcpe vol.16 no.3 (sept. 2015) -available online at: www.iasj.net rop=3.841wob 0.436 +0.001rpm 3.67 +0.001mw 0.892 +0.542q -2.668 … (7) in the second case a natural log form was conducted on logging grouped data. the results of regression analysis showed moderate strength of the model (r 2 =0.597).table (11) showed the values of coefficients for this model which has the following equation: lnrop=-10.8ln(wob)+18.6 ln(rpm)+17.3ln(mw)-59ln(q)… (8) conclusions 1an empirical linear model that relating rate of penetration with drilling parameters was developed for umm radhuma formation in zubair field , using mud logging data. 2the accuracy of the linear developed model could be enhanced by statistical processing which including removing of outliers, and grouping the logging data. 3a power modeling of logging data would also provide good estimation of rate of penetration, while the natural log model provided moderated estimation of rate of penetration. nomenclature df: degree of freedom k: no.of parameters mw: mud weight,ppg mse: mean of sum error msr: mean of sum residual n: no.of point data q: flow rate,l/m r: correletion coefficient. rpm: bit revolution per minute rop: rate of pentration,ft/hr ssr: sum of square regression sse: sum of square error(residual) wob: weight on bit,ton yi: actual value ῡ: mean value ỹ: predictive value references 1m.j.kaiser,a survey of drilling cost and complexity estimation models,int.j.pet.sci.tech,vol.1,no.1 ,pp.1-22,2007. 2t.bourgoyne,k.k.millheim and m.e.chenvert,applied drilling engineering,9 th edition,spe,richardson,tx,2003. 3f.akgun,drilling rate at technical limit,int.j.pet.sci.tech.,vol1.no.1,p p.99-118,2007 4j.ricardo,p.mendes and t.c.fonseca,applying a genetic neuro-model reference adaptive controller in drilling optimization,world oil mag.,vol.288,no.10,pp29-36,2007. 5t.bourgoyne and f.s.young,a multiple regression approach to optimal drilling and abnormal pressure detection ,soc.pet.j.,vol.14,no.4,pp.371384,1974. 6hong xu.,w.oliver and j,jensen,how to organize mud logging data for modeling rate of penetration,spe29252,1995. 7h.m.bahari,a.bahari,and h.moradi,intelligent rate predictor, int.j.inn.com.cnot.vol.7,no.4,april l2011. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.20 no.3 (september 2019) 1 – 6 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: hala n. abdulkareem, email: halan1988@yahoo.com , name: abeer i. alwared, email: dr.abeer.wared@coeng.uobadghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. performance of immobilized chlorella algae for removing pb(ii) ions from aqueous solution hala n. abdulkareem and abeer i. alwared environmental eng. department, university of baghdad abstract this study aims to show the effectiveness of immobilization of chlorella green algae biomass in the form of bead for the removal of lead ions from synthetic polluted water at various operational parameters such as ph (2–6), biosorbent dosage (0.5–20 g/l) and initial concentration (10–100 mg/l). more than 90 % removal efficiency was achieved. ftir and sem-edx analysis of the biosorbent before and after sorption show differences in the functional groups on the adsorbent surface. langmuir and freundlich equilibrium isotherm, pseudo-first-order and pseudo-second-order kinetic models were applied to the experimental and results and show good conformity with langmuir isotherm model and pseudo-second-order kinetic model with correlation coefficient (0.994) and (0.998) respectively. keywords: lead ions, chlorella green algae, biosorption, immobilization, isotherm, and kinetic models. received on 17/02/2019-, accepted on 03/04-/2019, published on 30/09/1029 https://doi.org/10.31699/ijcpe.2019.3.1 1introduction toxic metal ions removal from wastewater is important in economic and environmental problems. heavy metals and other metal ions contaminants are aqueous waste streams of many industries, such as mining and tanneries. some metals associated or released with these activities are pb, hg, cr, and cd. some of these metals accumulate in living organisms and cause various diseases and disorders. metals such as lead, mercury, arsenic, zinc, copper, and cadmium are highly toxic when adsorbed into the body causing accumulative poisoning, brain damage, cancer, and so forth. lead is an enzyme inhibitor and general metabolic poison that has the ability to replace calcium in the bone to form sites for long-term release, hence, the need to remove these toxic metals from water and wastewater is a point of interest. lead permissible limit in wastewater as set by the environment protection agency is 0.1 mg/l, and in drinking water, it is 0.05 mg/l ‎[1]. the conventional methods for heavy metals removal include chemical precipitation, electrodialysis, ion exchange, membrane separations, reverse osmosis, and solvent extraction which maybe not effective at low metal concentration and costly so the search for new, effective and economical technique for metal removal from wastewaters has directed attention to biosorption that uses various biological materials at little or no cost to remove heavy metal ‎[2]. biosorption, describes the removal of heavy metals from aqueous solution by using nonliving biomass. biosorption is favorable as an alternative to conventional methods of metal recovery from solutions due to availability and low-cost raw material. freely suspended biomass may have better contact with adsorbate during the removal process, suspended biomass maybe not the practical form to the direct use because of many problems, and one of them is the separation of the biomass from the treated water. immobilization suggested as an easy handling of the biomass, enhance its stability, reusability, mechanical strength, and the ease of separation and regeneration ‎[1]. this study aims to investigate the feasibility of using immobilized chlorella biomass for the removal of lead ions from aqueous solutions. the effects of different experimental parameters, such as initial ph, removal time, dose of sorbent and initial lead concentration on the sorption capacity were studied. 2materials and methods 2.1. sorbents and contaminant the algae used in the experiment were purchased from the buy algae web site (https://www.buyalgae.com/) as a pure dried sample of chlorella in a powdered form. the selected amount of the algal biomass mixed with 2% sodium alginate solution before that the algae wetted with a specific amount of distilled water, the mixture then dropped in a 5 % cacl2 solution left there in the solution for 2 hr to full solidification. the formed beads of diameter 4 ± 0.1 mm were washed with distilled water before using in the experiments. https://doi.org/10.31699/ijcpe.2019.3.1 h. n. abdulkareem and a. i. alwared / iraqi journal of chemical and petroleum engineering 20,3 (2019) 1 6 2 lead ions stock solution was prepared by dissolving the known amount of pb(no3)2 powder, in a known volume of distilled water different concentrations were prepared by dilution from the stock solution. then the ph of the aqueous solution was controlled using 0.1 m hcl and 0.1 m naoh to the required value. fig. 1 shows the algae before and after immobilization. (a) (b) fig. 1. chlorella algae (a) before (b) after immobilization 2.3. experimental work 250 ml conical-flasks were used in the experiments, each flask washed with hno3 diluted solution then washed with distilled water before starting the experiments. the flasks filled with 100 ml of pb(ii) ion solution and selected sorbent amount. in order to do the experimental work, several parameters were studied to examine their effect on the removal process such as ph, contact time, initial metal concentration, agitation speed, and sorbent dose. the agitation of flasks in the form of shaking was done for a defined time using orbital shaker (edmund buhler sm25, german). (10 ml) volume of the contaminated solution collected from each flask, without the need for further filtration, solutions analyzed to measure the remaining metal concentration. the measurements of metal ions carried out using atomic absorption spectrophotometer (aas, sens aa, australian) duplicate measurements of the samples were done for more accurate results. the removal efficiency of contaminants calculated from eq. (1): ( ) (1) where co and ce are the initial and equilibrium lead concentrations (mg/l). the amount of sorbate adsorbed on the sorbent material, qe (mg/g), can be determined by: ( ) (2) where m is the amount of sorbent on the flask (g) and v is the volume of contaminant solution (l) 3results and discussion 3.1. characteristic of immobilized beads a. ftir analysis fourier transform infrared (ftir) spectroscopy was used to identify the functional groups present in the biosorbent. the biomass samples were examined using the ftir spectrometer (model: ft/ir-4100typea) within range of 400-4000 cm -1 . analysis as can be seen in fig. 2 indicated the broad and strong bands at 3500 to 3000cm -1 which can be attributed to the overlapping of –oh and –nh stretching. the band at 2900 attributed to the c-h, at 1620 to 1590cm -1 due to the c=o, and amide groups, at 1400 cm -1 n-h bending in the amine groups, and at 1025 cm -1 to co stretching of alcohols and carboxylic acids. as compared to simple biosorbent, biosorbent loaded with chromium (vi) the broadening of -oh peak at 3440 cm -1 and carbonyl group peak at 1628 cm -1 was observed. this indicates the involvement of hydroxyl and carbonyl groups in the biosorption of metal ions ‎[3]. h. n. abdulkareem and a. i. alwared / iraqi journal of chemical and petroleum engineering 20,3 (2019) 1 6 3 fig. 2. ftir of immobilized chlorella black before lead removal red after lead removal b. sem-edx results sem-edx result of chlorella algae bead before and after pb (ii) ion deposit on the surface of beads as shown in fig.3. the edx also shows the composition of the surface of the alginate bead before and after sorption which indicate that change in light metal on alginate surface which support the theory of ion exchange during the removal process. (a) (b) (c) (d) fig. 3. sem-edx analysis of immobilized chlorella algae a sem before and b after lead removal c and d edx before and after lead removal respectively 3.2. effect of different parameter a. ph of the solution in the biosorption the initial ph of the solution is a very important parameter. the effect of this parameter was studied in a ph range, 2-6, and not exceeded 6 to avoid precipitation of heavy metal. fig. 4 shows removal efficiency variation with the variation of ph value. at ph value 2, the removal efficiency was low due to solution protonation that lower lead ion passing and compete with it. the removal efficiency starts to increase because functional groups such as carboxyl, phosphate, imidazole and amino groups, would be exposed due to deprotonation and carried negative charges, thus facilitating the biosorption of metal. 500750100012501500175020002500300035004000 1/cm 40 50 60 70 80 90 100 %t 3 8 5 3 .9 4 3 7 3 1 .4 5 3 4 3 6 .3 3 2 9 2 8 .0 7 2 8 7 2 .1 3 2 1 8 5 .4 4 1 6 4 9 .2 1 1 5 4 1 .1 9 1 4 4 2 .8 2 1 3 9 6 .5 2 1 2 4 0 .2 8 1 0 4 0 .6 4 6 4 6 .1 8 5 7 2 .8 8 5 3 5 .2 7 3 3 9 6 .7 9 2 9 3 0 .9 6 2 1 3 1 .4 3 1 6 4 9 .2 1 1 5 4 3 .1 2 1 4 3 9 .9 2 1 3 1 9 .3 7 1 2 4 4 .1 4 11 5 0 .5 9 1 0 3 9 .6 8 8 8 0 .5 4 5 7 5 .7 8 5 2 8 .5 2 smooth smooth 1 h. n. abdulkareem and a. i. alwared / iraqi journal of chemical and petroleum engineering 20,3 (2019) 1 6 4 at higher ph in basic conditions, the amount of oh ions is increased in the solution, so metal ions react with it and precipitated as a metal hydroxide ‎[4], ‎[5]. fig. 4. effect of ph on removal process b. sorbent dose doses of (0.05, 0.2, 0.6, 1 and, 2 gm) were used in different flasks with the same conditions to study their effect on the sorption process and the results are represented in fig.5 .the uptake capacity of the sorbent increased when decreasing biosorbent dosage because of interference between the binding sites on the surface, while increasing sorbent dose more than 1 gm/100, ml the quantity of metal ions uptake decreases because of the sites on the biosorbent surface remain unsaturated during the removal process ‎[6], ‎[7], ‎[8]. fig. 5. effect of dose on the removal process c. sorption time fig. 6 presents the removal efficiency of pb(ii) ions during different time periods. it can be seen from this figure that biosorption rate was increased rapidly at the initial stage of time from 0 to 30 and thereafter become nearly constant at around 90% then gradually the biosorption retarded due to the decrease in biosorption sites on the sorbent surface ‎[9]. fig. 6. effect contact time on the removal process d. initial lead concentration with increasing initial metal ions concentration the biosorption capacity also increased, high metal ions concentration provides a driving force that overcomes the resistance of the mass transfer layer between the beads and the metal in the solution. also, the biosorption process enhanced because of the number of collisions between metal ions and biosorbent increases when increasing initial metal concentration. the reduction in metal removal efficiency might be attributed to the insufficient binding sites for adsorption associated with increasing metal concentration, and that the binding was saturated ‎[9], ‎[10] as showed in fig. 7 fig. 7. effect of initial concentration on the removal efficiency of lead ions 4isotherm and kinetic studies 4.1. isotherm desorption isotherm which is the equilibrium relationship at a given temperature were studied by. langmuir, and freundlich, equations are used widely to describe sorption process. the importance of these models is finding the relationship between the sorbed amount of sorbate onto adsorbent (qe) and the concentration of sorbate remaining at equilibrium (ce) in the aqueous solution ‎[11]. 0 20 40 60 80 100 0 2 4 6 8 % r e m o v a l ph 0 10 20 30 40 50 60 70 80 90 100 0 1 2 3 % r e m o v a l dose (gm) 0 20 40 60 80 100 0 50 100 150 200 % r e m o v a l time (min) h. n. abdulkareem and a. i. alwared / iraqi journal of chemical and petroleum engineering 20,3 (2019) 1 6 5 a. langmuir model this model, suggests that sorption process occurs uniformly on the active sites of the sorbent at the surface, and once a sorbate occupies a site, no further sorption can take place at that site, langmuir model can be represented as ‎[12] (3) where b and qmax, are the langmuir constants, represent the saturated monolayer sorption capacity (mg/g), and the sorption equilibrium constant, and refer to the slope of the model. b. freundlich model (4) is an empirical model which suggests that sorption based on multilayer heterogeneous surface given by eq. (4) where 1/n is the intensity of sorption and k is a constant related to the maximum adsorption capacity ‎[13], ‎[14]. 4.2. sorption kinetics the transformation rate of pollutant from aqueous solution to solid phase [6] and the kinetic in the present study were represented using two models: a. pseudo-first order kinetic model ( ) (5) the qe and qt are the equilibrium and the amount of sorbate removed from the solution at time t respectively in (mg/g), and k1 is the pseudo first order rate constant (1/min) [15] b. pseudo-second order kinetic model this model can be described as: ( ) (6) where k2 is the pseudo second order rate constant (g/mg min) [16]. from the experimental results the relationships between the sored quantity (qe, mg/g) and the equilibrium concentration (ce) for pb(ii) ions in the solution. the values of the calculated parameters and the correlation coefficients (r2) are listed in table 1 and the models are represented in fig. 8 from the table the high correlation coefficients were found for the langmuir model which suggested that homogeneous surface of the sorbent with all the sorption sites assumed to have an equal sorbate affinity and the sorption occurs uniformly on sorbent active sites ‎[15]. the pseudo-second order model gave a better fit based on the r2 values. this indicating that sorption process occurred was chemisorption ‎[16]. table 1. constants of isotherm models for sorption of pb (ii) ion onto alginate bead isotherm model parameter value kinetic model parameter value langmuir (mg/g) 30.06 pseudofirst order qe (mg/g) 18.42 b (l/mg) 0.245 k1 (min −1 ) 0.346 r 2 0.994 r 2 0.74 freundlich ( )( ) 7.757 pseudosecond order qe (mg/g) 18.table 199 2.762 k2 (g/mg min) 0.045 r 2 0.873 r 2 0.998 fig. 8. isotherms and kinetic models for sorption pb (ii) ions onto alginate bead conclusions a non-conventional bio-carrier of immobilized chlorella green algal is a good way for lead ions removal from simulated wastewater without losing their ability to adsorb. different parameters studied and the isotherm shows that. langmuir isotherm model gives the best fit model for lead ions removal than freundlich models with the adsorption capacity. the monolayer adsorption capacity of pb(ii) ions calculated from the langmuir model was found 30.06mg/g, pseudo-second order kinetic model gives good fitting to present the process of removal which indicates according to the model controlling mechanism in the removal process is the chemisorption process. references [1] surisetty, v. r, kozinski, j., and nageswara, l.r., "biosorption of lead ions from aqueous solution using ficus benghalensis l".journal of engineering.id 167518,2013, [2] babarinde, n.a.a., babalola, j.o., and sanni, r.a., "biosorption of lead ions from aqueous solution by maize leaf" international journal of physical sciences,vol.1(1) ,2006, pp.023-026. 0 5 10 15 20 0 25 50 75 100 125 150 175 200 q e ( m g /g m ) time (min) pseudosecond-order pseudo-firstorder experemental b http://dx.doi.org/10.1155/2013/167518. http://dx.doi.org/10.1155/2013/167518. http://dx.doi.org/10.1155/2013/167518. http://dx.doi.org/10.1155/2013/167518. http://www.academicjournals.org/app/webroot/article/article1380099049_babarinde%20et%20al.pdf http://www.academicjournals.org/app/webroot/article/article1380099049_babarinde%20et%20al.pdf http://www.academicjournals.org/app/webroot/article/article1380099049_babarinde%20et%20al.pdf http://www.academicjournals.org/app/webroot/article/article1380099049_babarinde%20et%20al.pdf h. n. abdulkareem and a. i. alwared / iraqi journal of chemical and petroleum engineering 20,3 (2019) 1 6 6 [3] sharma, a. s.; and, bhalerao, s. a., "application of immobilized banana peels (musa paradisiaca l.) into calcium alginate beads for removal of chromium (vi) from aqueous solution" ijtsrd. vol.2 (2)2018, p 1310. [4] jayakumar,v.;govindaradjane, s,. "biosorption of cadmium by green algae a review". j. adv. chem. sci. 3(2),2017, pp 480–484. [5] rashid h.m. and faisal a. a.h. "removal of dissolved cadmium ions from contaminated wastewater using raw scrap zero-valent iron and zero valent aluminum as locally available and inexpensive sorbent wastes" ijcpe vol.(19 no.4) 2018, 39–45. [6] puranik, p.r.; paknikar, k.m., "biosorption of lead, cadmium and zinc by citrobacter strain mcmb characterization studies", biotechnol. prog. vol.(15) , 1999, pp 228-237. [7] ozer, a., dursun, g., "removal of methylene blue from aqueous solution by dehydrated wheat bran carbon" j. hazard. mater, vol.146 (1–2), 2007, pp262269. [8] theydan s.k., "effect of process variables, adsorption kinetics and equilibrium studies of hexavalent chromium removal from aqueous solution by date seeds and its activated carbon by zncl2" ijcpe vol.(20no.1) 2019, 23–29. [9] aksu z. "equilibrium and kinetic modelling of cadmium(ii) biosorption by c. vulgaris in a batch system: effect of temperature". sep purif technol.,vol.( 21), 2001, pp. 285–294. [10] a. f. ali and z. t. abd ali, “interaction of aqueous cu2+ ions with granules of crushed concrete”, ijcpe, vol. 20, no. 1, pp. 31-38, mar. 2019. [11] mohammed, a.; al-tahmazi, t.; babatunde, a. o., "attenuation of metal contamination in landfill leachate by dewatered waterworks sludges." ecological engineering, vol. 94 2016, pp656–667. [12] foo, k. y.; hameed, b. h.,. "insights into the modeling of adsorption isotherm systems." chemical engineering journal. 156(1) 2010 ,pp 2–10. [13] gheju, m.; miulescu, a., "sorption equilibrium of hexavalent chromium on granular activated carbon." chem. bull. politechnica univ. (timişoara). vol.52(12), 2008, pp41-46. [14] ho, y. s.; porter, j. f.; mckay, g., "equilibrium isotherm studies for the sorption of divalent metal ions onto peat: copper, nickel and lead single component systems." water, air, and soil pollution, vol141(1– 4,)2002, pp 1–33. [15] mohan, d.; pittman, c. u., "activated carbons and low cost adsorbents for remediation of triand hexavalent chromium from water. journal of hazardous materials, vol.137,2006, pp762 [16] ho, y.-s.; mckay, g., (1999) "pseudo-second order model for sorption processes." process biochemistry. 34(5), 1999,pp.451–465. كفاءة الطحالب المقيدة في ازالة الرصاص من المحاليل المائية عبير الوردهاله نصير و جامعة بغداد, قسم اليندسة البيئية الخالصة تيدف ىذه الدراسة إلى إظيار فعالية تجميد الكتمة الحيوية )الكموريال المجففة الخضراء( في شكل حبة كروية الشكل إلزالة أيونات الرصاص من المحاليل المائية المحضرة مختبريا في معايير تشغيمية مختمفة مثل الرقم تم .مجم / لتر 100 10والتركيز األولي ) (g / l (20-0.5) ( ، الجرعة البيولوجية6–2الييدروجيني ) وتحميل المجيرية واالشعة ftir ٪ ومن خالل عمل تحميل 00الحصول عمى كفاءة إزالة بمغت أكثر من ظير الفرق في المجموعات لكرات االلجنيت المقيدة فييا الطحالب قبل وبعد االمتصاص sem-edxالسينية تم تطبيق موديالت الوظيفية عمى سطح المادة المازة نتيجة التبادل االيوني الحاصل خالل عممية االزالة. كما ( بمعامل الرتباط langmuir( وكان اكثرىا انطباقا مع النتائج موديل )freundlich و langmuirالتوازن ) r2= (0.994) ( والموديالت الحركيةpseudo-first-order و pseudo-second-order كان اكثرىا ) r2 = (0.998). ( بمعامل ارتباطpseudo-second-orderتماشيا مع النتائج موديل ) ، موديالت رياضية وحركية : تقييد، المعادن الثقيمة، طحالب الكموريال الميتو، االمتزاز الحيويدالةلكممات الا https://www.academia.edu/36131792/application_of_immobilized_banana_peels_musa_paradisiaca_l._into_calcium_alginate_beads_for_removal_of_chromium_vi_from_aqueous_solution https://www.academia.edu/36131792/application_of_immobilized_banana_peels_musa_paradisiaca_l._into_calcium_alginate_beads_for_removal_of_chromium_vi_from_aqueous_solution https://www.academia.edu/36131792/application_of_immobilized_banana_peels_musa_paradisiaca_l._into_calcium_alginate_beads_for_removal_of_chromium_vi_from_aqueous_solution https://www.academia.edu/36131792/application_of_immobilized_banana_peels_musa_paradisiaca_l._into_calcium_alginate_beads_for_removal_of_chromium_vi_from_aqueous_solution http://jacsdirectory.com/journal-of-advanced-chemical-sciences/admin/issues/20170730181346_3-2-07%20jacs17151%20published.pdf http://jacsdirectory.com/journal-of-advanced-chemical-sciences/admin/issues/20170730181346_3-2-07%20jacs17151%20published.pdf http://jacsdirectory.com/journal-of-advanced-chemical-sciences/admin/issues/20170730181346_3-2-07%20jacs17151%20published.pdf http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/507 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/507 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/507 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/507 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/507 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/507 https://www.ncbi.nlm.nih.gov/pubmed/10194398 https://www.ncbi.nlm.nih.gov/pubmed/10194398 https://www.ncbi.nlm.nih.gov/pubmed/10194398 https://www.ncbi.nlm.nih.gov/pubmed/10194398 https://doi.org/10.1016/j.jhazmat.2006.12.016 https://doi.org/10.1016/j.jhazmat.2006.12.016 https://doi.org/10.1016/j.jhazmat.2006.12.016 https://doi.org/10.1016/j.jhazmat.2006.12.016 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/220 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/220 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/220 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/220 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/220 https://www.sciencedirect.com/science/article/pii/s1383586600002124 https://www.sciencedirect.com/science/article/pii/s1383586600002124 https://www.sciencedirect.com/science/article/pii/s1383586600002124 https://www.sciencedirect.com/science/article/pii/s1383586600002124 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/513 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/513 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/513 https://doi.org/10.1016/j.ecoleng.2016.06.123. https://doi.org/10.1016/j.ecoleng.2016.06.123. https://doi.org/10.1016/j.ecoleng.2016.06.123. https://doi.org/10.1016/j.ecoleng.2016.06.123. https://www.sciencedirect.com/science/article/pii/s1385894709006147 https://www.sciencedirect.com/science/article/pii/s1385894709006147 https://www.sciencedirect.com/science/article/pii/s1385894709006147 http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.492.1175&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.492.1175&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.492.1175&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.492.1175&rep=rep1&type=pdf https://link.springer.com/article/10.1023/a:1021304828010 https://link.springer.com/article/10.1023/a:1021304828010 https://link.springer.com/article/10.1023/a:1021304828010 https://link.springer.com/article/10.1023/a:1021304828010 https://link.springer.com/article/10.1023/a:1021304828010 https://doi.org/10.1016/j.jhazmat.2006.06.060 https://doi.org/10.1016/j.jhazmat.2006.06.060 https://doi.org/10.1016/j.jhazmat.2006.06.060 https://doi.org/10.1016/j.jhazmat.2006.06.060 https://www.sciencedirect.com/science/article/pii/s0032959298001125 https://www.sciencedirect.com/science/article/pii/s0032959298001125 https://www.sciencedirect.com/science/article/pii/s0032959298001125 iraqi journal of chemical and petroleum engineering vol.17 no.4 (december 2016) 95103 issn: 1997-4884 chromium (vi) removal from wastewater by electrocoagulation process using taguchi method: batch experiments amenah s. al-nuaimi and kamal s. pak collage of engineering al-nahrain university e-mail: am.sa91@yahoo.com and dr_kamal_shakir@yahoo.com abstract electrocoagulation is an electrochemical method for treatment of different types of wastewater whereby sacrificial anodes corrode to release active coagulant (usually aluminium or iron cations) into solution, while simultaneous evolution of hydrogen at the cathode allows for pollutant removal by flotation or settling. the taguchi method was applied as an experimental design and to determine the best conditions for chromium (vi) removal from wastewater. various parameters in a batch stirred tank by iron metal electrodes: ph, initial chromium concentration, current density, distance between electrodes and kcl concentration were investigated, and the results have been analyzed using signal-to-noise (s/n) ratio. it was found that the removal efficiency of chromium increased with increasing current density and kcl concentration, and decreases with increasing initial chromium concentration and distance between electrodes, while ph shows peak performance curve. experimental work have been performed for synthetic solutions and real industrial effluent. the results showed that the removal efficiency of synthetic solution is higher than industrial wastewater, the maximum removal for prepared solution is 91.72 %, while it was 73.54 % for industrial wastewater for the same conditions. key words: electrocoagulation, chromium (vi) removal, taguchi method, iron electrodes. introduction rivers, channels, and other water resources are always in danger of pollutions as a result of the industrial wastewater discharge and other natural activities [1]. the problem of generating hazardous waste has been increasing recently due to the rapid growth of industrialization activities in the world. since water is used in large quantities in most of the industrial activities the major part of waste that has been discharged to the environment and cause a serious pollution effects is the wastewater [2]. heavy metals, including (chromium, copper, cadmium, zinc, and so forth) are the most common pollutants which usually exist in a high concentrations in industrial wastewater and they damage could the aquatic environment and threaten human’s health [3]. the two typical oxidative states of chromium in the environment are university of baghdad college of engineering iraqi journal of chemical and petroleum engineering mailto:am.sa91@yahoo.com mailto:dr_kamal_shakir@yahoo.com chromium (vi) removal from wastewater by electrocoagulation process using taguchi method: batch experiments 96 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net hexavalent, cr (vi), and trivalent, cr (iii). these two oxidation states have widely contrasting toxicity and transport characteristics: hexavalent chromium is more toxic, with high water solubility and mobility, while trivalent chromium is less soluble in water, less mobile and less harmful [4]. electrocoagulation is a simple and efficient method to remove the flocculating agent generated by electrooxidation of a sacrificial anode and generally made of iron or aluminum. in this process, the treatment is performed without adding any chemical coagulant or flocculants, thus reducing the amount of sludge which must be disposed. on the other hand, electrocoagulation is based on the in situ formation of the coagulant as the sacrificial anode corrodes due to an applied current, while the simultaneous evolution of hydrogen at the cathode allows for pollutant removal by flotation. this technique combines three main interdependent processes, operating synergistically to remove pollutants: electrochemistry, coagulation and hydrodynamics [5, 6]. contaminant removal with electrochemical method offers several advantages, such as the absence of chemical requirements, lower volume of sludge produced,economic aspects (relatively low investment, maintenance, energy, and treatment costs), simple equipment and compact size of ec systems and the small area occupied by the plant and the ease of operation [7]. electrolysis is a process in which oxidation and reduction reactions take place when electric current is applied to an electrolytic solution. electrocoagulation is based on dissolution of the electrode material used as an anode. this so-called “sacrificial anode” produces metal ions which act as coagulant agents in the aqueous solution in situ [8]. at its simplest, an electrocoagulation system consists of an anode and a cathode made of metal plates, both submerged in the aqueous solution being treated [9]. the electrodes are usually made of aluminum or iron (carbon steel or stainless steel), because these metals are cheap, readily available, proven effective, and non-toxic. thus they have been adopted as the main electrode materials used in ec systems [10, 11]. the mechanisms of ec for water and wastewater treatment are very complex. it is generally believed that there are three other possible mechanisms involved besides ec, i.e. electroflotation, electrochemical oxidation and adsorption. the main electrochemical reactions at the electrodes during ec process [12]. anodic reactions, sacrificial metal fe is dissolved [13]: fe(s)fe 2+ +2e  e º = +0.44 v … (1) 2h2o(l)o2(g)+4h + +4e  e º = 1.23 v … (2) ferrous iron may be oxidized to fe 3+ by atmospheric oxygen or anode oxidation, and may be considered as [14]: fe 2+  fe 3+ + e  e º = 0.77 v… (3) fe 2+ + o2(g)+h2o(l)2fe 3+ +2oh  e º =0.37v … (4) at cathodic reactions, h2 gas is liberated [13]: 2h2o+2e  h2(g)+2oh  e º = 0.83 v … (5) the anodically formed fe 3+ combines with the cathodically formed oh  to produce insoluble fe(oh)3. http://www.iasj.net/ amenah s. al-nuaimi and kamal s. pak -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 97 fe 3+ +3oh  fe(oh)3 … (6) additionally, when chloride is present and the anode potential is sufficiently high, the following reactions may take place in the ec cell [15]: 2cl   cl2 + 2e  e º = 1.36 v… (7) cl2+h2ohclo+ h + +cl  e º =0.93 v … (8) hcloh + +ocl  … (9) the formation of active chlorine species (cl2, hclo, ocl  ) enhances the performance of the ec reactor through oxidation reactions. the aim of this work to studying the parameters that are effective on the percentage of chromate removal in a batch stirred tank by iron metal electrodes. furthermore finding the best conditions for the process , the studied parameter are: ph change, initial chromium concentration, current density, concentration of kcl salt, distance between the two electrodes (anode and cathode) by using iron metal (carbon steel) of electrode. material and methods the schematic diagram of a batch experimental set up as shown in figure 1. a stock solution 1000 mg/l of chromate was prepared by dissolving 1.362 gram of potassium dichromate (k2cr2o7) in 1000 ml deionized water . other concentrations were prepared daily from stock solution by dilution in the range 50, 100, 300, and 500 mg/l, according to equation below: v1 c1 = v2 c2 … (10) the initial ph of the solution was adjusted by using 0.1 n naoh or 0.1 n h2so4. (1) dc power supply; (2) ec cell; (3) teflon bar (4) magnetic stirrer. fig. 1: schematic diagram of batch electrocoagulation (ec) process unit uv-visible spectrophotometer (jenway model 6800 double beam) was employed to determine the remaining concentrations of cr (vi) in the sample. the filtrate was analysed for the remaining cr (vi) concentration. a real industrial wastewater containing chromium was supplied by the general company for electrical industries that located in alwaziriya/baghdad to compare the removal efficiency with the synthetic solution. analysis of this wastewater was done in the corporation of research and industrial development/ energy and environment research center by using device icp (inductive coupled plasma), agilent technologies, model (700 series icp-oes) and the properties of real samples of industrial wastewater as given in table 1. table 1: characteristic of industrial wastewater 6.75 ph 488.427 ppm cr (vi) 0.187 ppm cd 0.673 ppm as 0.087 ppm mn 53.773 ppm zn 0.022 ppm ba 0.022 ppm cu 0.0799 ppm ni the percent removal of chromate was calculated using the equation 11: v a 1 2 3 4 http://www.iasj.net/ chromium (vi) removal from wastewater by electrocoagulation process using taguchi method: batch experiments 98 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net % removal = ( ) 100% … (11) where: ci is the initial concentration of chromium and ct is the final concentration of chromium. the batch operation mode was done to study the effect of several parameters: initial ph, initial chromium concentration, current density, distance between electrodes and concentration of kcl. all the variables studied are illustrated in details as given in table 2. table 2: various parameters tested in batch mode experiments parameters tested value ph 3, 5, 7, 9 initial concentration (mg/l) 50, 100, 300, 500 current density (ma/cm 2 ) 2, 6, 10, 14 distance between the electrode (cm) 1, 2.5, 4, 5.5 concentration of kcl (g/l) 1, 5, 10, 15 experimental design taguchi method involves reducing the variation in a process through robust design of experiments. the experimental design proposed by taguchi involves using orthogonal arrays to organize the parameters affecting the process and the levels at which they should be varied; it allows for the collection of the necessary data to determine which factors most affect product quality with a minimum amount of experimentation, thus saving time and resources. analysis of variance on the collected data from the taguchi design of experiments can be used to select new parameter values to optimize the performance characteristic [16]. the taguchi’s experimental design results are transformed into a signal-tonoise (s/n) ratio. table 3 shows the results and corresponding calculated s/n ratio data for chromium removal. s/n calculation was performed and calculated from equation 12 to maximize % response i.e. the percentage of chromium removal by electrocoagulation (larger is better). snl=10log10[ ∑ 1/yi 2 ] …(12) the effect of each process parameter (delta = maximum – minimum) was estimated by averaging the s/n ratios and means for all the experiments as given in table 4 and table 5. table 3: experimental layout for using the orthogonal array (oa) and experimental result for chromium removal by electrocoagulation no. ph ci (mg/l) current density (ma/cm 2 ) distance (cm) kcl concentration (g/l) removal% after 60 min s/n ratio mean first second 1 3 50 2 1 1 81.8 81.0 38.21 81.4 2 3 100 6 2.5 5 92.3 88.2 39.10 90.25 3 3 300 10 4 10 71.4 73.6 37.20 72.5 4 3 500 14 5.5 15 54.9 48.7 34.23 51.8 5 5 50 6 4 15 95.6 93.0 39.48 94.3 6 5 100 2 5.5 10 74.92 71.38 37.27 73.15 7 5 300 14 1 5 77.8 92.0 38.48 84.9 8 5 500 10 2.5 1 49.8 49.0 33.87 49.4 9 7 50 10 5.5 5 94.8 87.2 39.15 91.0 10 7 100 14 4 1 100.0 100.0 40.0 100.0 11 7 300 2 2.5 15 64.6 70.8 36.58 67.7 12 7 500 6 1 10 58.5 58.1 35.31 58.3 13 9 50 14 2.5 10 100.0 100.0 40.0 100.0 14 9 100 10 1 15 98.4 100.0 39.92 99.2 15 9 300 6 5.5 1 63.5 59.5 35.76 61.5 16 9 500 2 4 5 36.8 30.0 30.33 33.4 http://www.iasj.net/ amenah s. al-nuaimi and kamal s. pak -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 99 table 4: response signal to noise ratios level ph initial con. current density distance con. of kcl 1 37.19 39.21 35.60 37.99 36.96 2 37.28 39.08 37.42 37.39 36.77 3 37.76 37.01 37.54 36.76 37.45 4 36.51 33.44 38.18 36.61 37.56 delta 1.26 5.77 2.58 1.38 0.79 rank 4 1 2 3 5 table 5: response for means level ph initial con. current density distance con. of kcl 1 73.99 91.67 63.91 80.95 73.08 2 75.44 90.65 76.09 76.84 74.89 3 79.25 71.65 78.03 75.05 75.99 4 73.52 48.23 84.17 69.36 78.25 delta 5.73 43.45 20.26 11.59 5.17 rank 4 1 2 3 5 results and discussions effect of initial ph it has been established that ph is an important parameter that affected on the efficiency of the electrocoagulation process. a set of experiments was performed by varying the ph as 3, 5, 7 and 9 of the synthetic potassium dichromate solution to study the effect of ph on the hexavalent chromium removal efficiency. the solutions were adjusted to the desired ph for each experiment using sodium hydroxide or sulfuric acid solution 0.1 n. the results after 60 min are shown in figure 2. it can be noticed that the ph of the solution has a significant effect on the cr (vi) removal efficiency, also as observed by other investigators, the ph of the solution was changed during the process. this change depends on the type of electrode material and initial ph and alkalinity. the cr (vi) removal efficiency was found to increase with increase in the ph of the solution from 3 to 7, is ascribed to the hydrogen evolution and the generation of oh ¯ ions at the cathode. while the removal efficiency substantially decrease at ph ˃7. in alkaline medium (ph ˃ 7) the final ph does not change markedly because the generated oh ¯ ions at the cathodes are consumed by the generated fe 3+ ions at the anode forming the needed fe(oh)3 flocs. furthermore, oh ¯ ions can also partially combine with chromium ions to form the insoluble hydroxide precipitates cr(oh)3. for this reason, in alkaline medium no ph increase is noticed but a slight ph decrease. fig. 2: effect of initial ph of solution on cr(vi) removal efficiency effect of initial concentration chromium solutions with different initial concentrations in the range of 50–500 mg/l were treated by electrocoagulation. figure 3 show the effect of initial concentration on the removal of chromium, it was observed that when increasing the initial http://www.iasj.net/ chromium (vi) removal from wastewater by electrocoagulation process using taguchi method: batch experiments 100 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net concentration the chromium removal efficiency decreases. the removal efficiency respectively equaled 91.67, 90.65, 71.65, and 48.23 percent for the initial concentrations of 50, 100, 300 and 500 milligram per liter of chromium during 60 minutes electrolysis. this is due to two factors: (i) under the present experimental conditions, available fe(oh)3 coagulant is limited and their active surface area can become fully saturated with cr (vi) and cr (iii) ions with no more active surface left to adsorb further chromium ions. (ii) it is also possible that higher cr (vi) concentration tends to passivate the anode chemically. fig. 3: effect of initial concentration of solution on cr(vi) removal efficiency effect of current density the current density is one of the important parameters to control the reaction rate in the electrochemical processes. the current density determines the coagulant dosage rate, the bubble production rate and size and the floc growth resulting in a faster removal of pollutants. a large current means a small electrocoagulation unit. however, when too large current is used, there is a high chance of wasting electrical energy. a series of experiments were carried out to evaluate the effect of current density on cr(vi) removal efficiency. the current density was varied from 2 to 14 ma/cm 2 , and the results are shown in figure 4. fig. 4: effect of current density on cr (vi) removal efficiency it can be noticed that there is an increase in the chromium removal efficiency with an increase in the current density. the highest chromium removal efficiency was achieved with an applied current of 14 ma/cm 2 for an electrolysis time after 60 min. effect of the distance between eectrodes to examine the effect of electrode distance on the electrocoagulation process, experiments were conducted by varing electrode distances 1, 2.5, 4 and 5.5 cm and the results are shown in figure 5. it was observed that when the distance between electrodes (d) increased, the cr (vi) removal efficiency decreased. when d was 1 cm, the cr(vi) removal efficiency = 80.95, while when d was increase to 5.5 cm, the removal efficiency decreased to 69.36 %. fig. 5: effect of distance between the electrodes on cr (vi) removal efficiency http://www.iasj.net/ amenah s. al-nuaimi and kamal s. pak -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 101 effect of potassium chloride concentration in all experiments, electrolyte solution contains kcl with varying conductivity because it is easily found in water and wastewater. a set of experiments was performed by varying the concentration as 1, 5, 10 and 15 g/l of potassium chloride to study the effect on the hexavalent chromium removal efficiency, the results were shown in figure 6. it was observed that when the kcl electrolyte solution concentration increased, the cr (vi) removal efficiency increased. when the kcl concentration of the feed solution was raised to 15 g/l , the cr (vi) removal efficiency increases to 78.25% after 60 min of electrocoagulation, because it increased conductivity of the solution and thus reduced the energy consumption. fig. 6: effect of kcl concentration on cr(vi) removal efficiency treatment of real industrial wastewater a comparison between the synthetic and real industrial wastewater supplied from chromium plating unit at the general company for electrical industries in baghdad is shown in figure 7. the result shows that the removal efficiency for synthetic solution was higher than industrial solution at the same operating conditions. fig. 7: comparison between synthetic and industrial wastewater for batch mode experiments (ph=6.7, ci=488.427 mg/l, i=14 ma/cm 2 , d=1cm, ckcl=15g/l) from figure 7 for batch mode, it was observed that the percent of chromate removal for synthetic solution is higher than that of industrial solution for ph = 6.7, initial concentration of chromium = 488.427 mg/l, current density = 14 ma/cm 2 , distance between electrodes = 1 cm and kcl concentration = 15 g/l. the removal efficiency of synthetic solution after 90 min was 91.72 % while industrial wastewater showed 73.54 %. this may be because the presence of other impurities (such as metal ions) in the real wastewater which may interfere in the electrocoagulation process. conclusions from the present work, it can be conclude that: http://www.iasj.net/ chromium (vi) removal from wastewater by electrocoagulation process using taguchi method: batch experiments 102 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net 1. the electrocoagulation process is successfully applied to remove chromium from aqueous solution. the chromium removal efficiency was found to be dependent on ph of the solution, the initial chromium concentration, applied current density, distance between electrodes and kcl concentration. 2. the optimum ph for chromium removal efficiency is 7. 3. in batch operation mode, the results showed that applied current density, and kcl concentration are directly proportional to chromium removal efficiency, while initial chromium concentration, and distance between electrodes were inversely proportional to chromium removal efficiency, while ph showed a peak performance curve. 4. the best conditions for wastewater treatment in the range of used parameters were initial concentration = 50 mg/l, current density = 14 ma/cm 2 , distance between electrodes = 1 cm, kcl concentration = 15 g/l. 5. the removal efficiency of prepared solution was higher than industrial wastewater. in batch system the maximum removal efficiency obtained for synthetic solution was 91.72 %, while for industrial wastewater was approximately 73.54%. references 1. merzouk,b., b. gourich, a. sekki, k. madani, m. chibane (2009), “removal turbidity and separation of heavy metals using electrocoagulation – electrocoagulation technique, of hazardous materials”, 164, pp 21 – 22. 2. jorgensen, erik, seven, (1979), “industrial wastewater management” elsevier scientific publishing comp., (pp. 309-312). 3. zarafshan, a., mahvi, a. (2007), “electrocoagulation application via aluminum electrodes in removal of cadmium in aqueous environment. tabib-esharq magazine”, no.1, year.9, pp:61-70. 4. mohan, d. and c. pittman jr., (2006) “activated carbons and lowcost adsorbents for remediation of triand hexavalent chromium from water”, journal of hazardous materials b, vol. 137, pp. 762-811. 5. naje, a.s., and s.a abbas, (2013), “electrocoagulation technology in wastewater treatment”, issn 22245790, vol.3, no.11. 6. bazrafshan, e., k.al din ownaghi and a.h.mahvi, (2012), “application of electrocoagulation process using iron and aluminum electrodes for fluoride removal from aqueous environment”, e-journal of chemistry. 7. szpyrkowicz, l., s. daniele, m. radaelli, and s. specchi, (2006), “removal of no 3 from water by electrochemical reduction in different reactor configurations”, appl. catal. benviron. vol. 66, pp. 40–50. 8. holt, p. k., g. w. barton and c. a. mitchell, (2005) “the future for electrocoagulation as a localised water treatment technology” chemosphere, vol. 59, 355-367. 9. emamjomeh, m. m. and m. sivakumar, (2009), “review of pollutants removed by electrocoagulation and electrocoagulation/flotation processes,” journal of environmental management, vol. 90, no. 5, pp. 1663-1679. 10. kumar, p. r., s. chaudhari, k. c. khilar and s. p. mahajan, (2004), “removal of arsenic from water by electrocoagulation,” chemosphere, vol. 55, no. 9, pp. 12451252. 11. chen, x., g. chen and p. l. yue, (2000), “separation of pollutants http://www.iasj.net/ amenah s. al-nuaimi and kamal s. pak -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 103 from restaurant wastewater by electrocoagulation,” separation and purification technology, vol. 19, no. 1-2, pp. 65-76. 12. katal, r. and pahlavanzadeh, h., (2011), “influence of different combinations of aluminum and iron electrode on electrocoagulation efficiency” application to the treatment of paper mill wastewater. desalination 265, p. 199–205. 13. chen, g., (2004), “electrochemical technologies in wastewater treatment,” separation and purification technology, vol. 38, no. 1, pp. 11-41. 14. zodi, s., o. potier, f. lapicque and j. leclerc, (2009) “treatment of the textile wastewaters by electrocoagulation: effect of operating parameters on the sludge settling characteristics,” separation and purification technology, vol. 69, no. 1, pp. 2936. 15. gao, s., m. du, j. tian, j. yang, j. yang, f. ma and j. nan, (2010), “effects of chl flotation process with aluminum electrodes for algae removal,” journal of hazardous materials, vol. 182, no. 1-3, pp. 827-834. 16. taguchi, g., s. chowdhury, y. wu, (2005), taguchi’s quality engineering handbook. john wiley & sons, new jersey. http://www.iasj.net/ ijcpe vol.11 no.2 (june 2010) iraqi journal of chemical and petroleum engineering vol.11 no.2 (june2010) 29-33 issn: 1997-4884 producing oil from dead oil wells using injected lpg g.a.r.rassoul, and omar m. waheeb chemical engineering department-college of engineering-baghdad university abstract in order to reduce hydrostatic pressure in oil wells and produce oil from dead oil wells, laboratory rig was constructed, by injecting lpg through pipe containing mixture of two to one part of east baghdad crude oil and water. the used pressure of injection was 2.0 bar, which results the hydrostatic pressure reduction around 246 to 222 mbar and flow rate of 34.5 liter/hr fluid (oil-water), at 220 cm injection depth. effects of other operating parameters were also studied on the behavior of two phase flow and on the production of oil from dead oil wells. keywords: dead oil well, injecting lpg, vertical two phase flow, lpg-oil-water mixture. ________________________________________________________________________________________________ introduction during oil production, oil water level rises in the reservoirs which increase water content in produced oil in the wells near oil water contact. this water together with declining reservoir pressure during life of producing wells, decreasing oil production. increasing hydrostatic pressure will also decrease oil production. it is not uncommon for the reservoir pressure in typical oil wells to be insufficient to cause a produced fluid to flow naturally from the well. in such situations, the produced fluid (usually a multi-phase fluid containing gas, oil and water) must be artificially raised to the surface, and the typical methods currently used to artificially raise the fluid are submersible or beam pump and gas-lift. submersible and beam pumping as well as gas-lift are applicable to surface facility forms (onshore on platforms). beam pumping is not applied to subsurface well applications. in deep wells, beam pumping is not routinely used because the extensibility of sucker rods used for pumping deprives the pump of a sufficient stroke. in such cases, gas-lift is often used when there is sufficient gas-lift gas available. in gas-lift methods of production, a production tubing string is installed within the cased opening. production is attained through this production tubing. the annulus outside the production string, but within the cased hole, is used as the downward path for communication of gas, which is used by the gaslift equipment. the process consists of forcing (compressing) gas under high pressure into the annulus. at the gas-lift equipment, gas is introduced into the production or tubing string to reduce the density of petroleum liquid produced from a deep formation so that the liquid will rise in the production tube. hence, gas-lift valves located in side pocket mandrels are installed at various elevations within production tubing, and are adjusted in depth to reduce hydrostatic pressure. the lower the gas-lift valve the more liquid is lifted in the well (edward, marshall, and dennis 2000). the reducing of hydrostatic pressure depends upon the differences in the viscosity, density, and surface tension between the injected gas and water oil mixture. solubility of injected fluid, and fluid miscibility and fluid compatibility affects oil-water production. similarly the availability of the injected fluids and specially the fluids obtained from degassing stations near oil wells which are produced as a side product can also used to increase the oil production from unproducable wells or from dead oil wells. the production of the oil from this process is (usually a multi-phase fluid containing gas, oil and water) and the university of baghdad college of engineering iraqi journal of chemical and petroleum engineering producing oil from dead oil wells using injected lpg ijcpe vol.11 no.2 (june 2010) 30 type of vertical flow regime which can be specified by gas void fraction or backer chart is one of the following types (bubble flow , slug flow, annular flow, and mist dispersed flow) the aim of present study was to reduce hydrostatic pressure of crude oil and to estimate the suitable injection pressure and the depth of injection using lpg. experimental work east baghdad crude oil was supplied from alduara refinery, tap water was supplied, and lpg gas cylinder was used as injected gas. laboratory rig was constructed which consists of three concentric pipes. the outer one is an oil reservoir of 15.24 cm in diameter and the second insider one is an oil producer of 10.16 cm in diameter and the center pipe is gas injection 2.54 cm which is attached to thirteen solenoids valve, top reservoir tank of 105 cm in diameter, digital control panel, two pressure transmitters, pressure gauge, two liquid flow meters, gas flow meter and gas source i.e. lpg gas cylinder the made up oil reservoir consisted of two parts east baghdad crude oil mixed with one part water. the 126 liters of east baghdad crude oil had been mixed with 54 liters of water to make a 30% water oil mixture. the mixture was placed in a top reservoir (open storage tank) to fill production units and this mixture filled the 4, and 6 in pipes continuously. then the whole system connected to a source of electric power. using lpg was injected gases inside oil water mixture at injection pressures 0.5, 1.0, 1.5, and 2.0 bar, and at injection depth from 280 to 220 cm. by regulating gas injection pressure and open the valve at the position and then recording bottom-hole pressure, gas injection pressure in the control panel, top-hole pressure by pressure gauge, liquid flow rate, and gas flow rate. fig. 1 experimental setup for oil production g.a.r.rassoul, and omar m. waheeb ijcpe vol.11 no.2 (june 2010) 31 resulits and discussion in this study 28 experimental runs were carried out for the lpg gas injection through oil water mixture. the effects of depths of injection, and gas injection pressure on the bottom-hole pressure, top-hole pressure, and liquid flow rate were studied. effects of injection depths effects of injection depths on the bottom-hole pressure figure 2 represents the relationship between bottom-hole pressure and injection depths, at different injection pressures. it is clearly that bottom-hole pressure decreases with decreasing injection depths. when lpg injected inside liquid mixture which is soluble with oil and similar to the composition of oil (hydrocarbon) and also miscible with water also, lpg reducing the density of liquid mixture (reducing hydrostatic pressure) as the depth decreasing the amount of the liquid uprising from the liquid column increasing and this reduce the bottom-hole pressure. the effects of injection depth on the top-hole pressure figure 3 represents the relationship between top-hole pressure and injection depths, at different injection pressures. it is clearly that top-hole pressure increases with decreasing injection depths. when lpg injected inside liquid mixture as the depth decreases, liquid flow rate increases which mean more liquid effects on the top of the pipe. the effect of the injection depth on the liquid flow rate figure 4 represents the relationship between liquid flow rate and injection depths, at different injection pressures. it is clearly that liquid flow rate increases with decreasing injection depths. decreasing in the injection depth that mean decreasing in the pressure head of the column which mean that the resistance due to gas injected at 220 cm depth is less than 280 cm depth. drag forces that liquid exposed will to decrease water-oil production. fig (2) bottom-hole pressure verses depth of injection at different pressures of injected lpg 210 215 220 225 230 235 240 245 280 270 260 250 240 230 220 depth of injection (cm) b o tt o m -h o le p re s s u re ( m b a r) p= 0.5 bar p= 1.0 bar p= 1.5 bar p= 2.0 bar fig (3) top-hole pressure verses depth of injection at different pressures of injected lpg 32 33 34 35 36 37 38 39 40 280 270 260 250 240 230 220 depth of injection (cm) t o p -h o le p r e s s u r e ( m b a r ) p= 0.5 bar p= 1.0 bar p= 1.5 bar p= 2.0 bar fig(4) liquid flow rate verses depth of injection at different pressures of injected lpg 0 50 100 150 200 250 300 350 400 450 280 270 260 250 240 230 220 depth of injection (cm) l iq u id f lo w r a te ( l/ h r) p= 0.5 bar p=1.0 bar p= 1.5 bar p= 2.0 bar producing oil from dead oil wells using injected lpg ijcpe vol.11 no.2 (june 2010) 32 effects of injection pressure effects of injection pressures on the bottom-hole pressure figure 5 represents the relationship between bottom-hole pressure and injection pressures, at different injection depths. it is clearly that bottom-hole pressure decreases with increasing gas injection pressure. as the gas injection pressure increases, the amount of injected gas is more and density of the mixture will be reduced more than at low pressures. effects of injection pressures on the top-hole pressure figure 6 represents the relationship between top-hole pressure and injection pressures, at different injection depths. it is clearly that top-hole pressure decreases with increasing gas injection pressure. at high pressures of injected gas fast penetration of injected gas through liquid mixture which become less in its effect on the wall because of the density become less than before and that means amount of gas is too high and this lead to low pressure. the effects of injection pressure on the liquid flow rate figure 7 represents the relationship between liquid flow rate and injection pressures, at different injection depths. it is clearly that liquid flow rate increases with increasing injection pressures. pressure of injected gas increases which means increasing the amount injected gas. this will give high flow rate of liquid due partly because reduction in the liquid mixture density and partly because increase lifting pressure at the bottom of the liquid mixture and also because the solubility of the gases in the liquid phase. type of two phase flow the type of two phase flow regime can be specified by evaluating the gas void fraction (α') which specify the flow regime which was annular vertical two phase flow through the all runs conclusions the injection gas inside oil water mixture to reduce hydrostatic pressure of liquid column by reducing the density of the mixture mixed with liquid mixture when the gas injected inside liquid mixture gas mixed with liquid mixture and soluble inside it. this solubility increased by increasing the pressure of injection. the hydrostatic pressure reduced from 246 to 220 mbar and giving of 334 l/hr fluid (oil-water) flow rate at 2.0 bar gas injection pressure and at 220 cm depth of injection. fig (6) top-hole pressure verses pressure of injected lpg at different depths of injection 30 31 32 33 34 35 36 37 38 39 0.5 1 1.5 2 pressure of injecttion (bar) t o p -h o le p re s s u re ( m b a r) d= 280 cm d= 270 cm d= 260 cm d= 250 cm d= 240 cm d= 230 cm d= 220 cm fig(7) liquid flow rate verses pressure of injected lpg at different depths of injection 0 50 100 150 200 250 300 350 400 0.5 1 1.5 2 pressure of injection (bar) l iq u id f lo w r a te ( l/ h r) d= 280 cm d= 270 cm d= 260 cm d= 250 cm d= 240 cm d= 230 cm d= 220 cm fig (5) bottom-hole pressure verses pressure of injected lpg at different depths of injection 210 215 220 225 230 235 240 245 0.5 1 1.5 2 pressure of injected lpg (bar) b o tt o m -h o le p re s s u re ( m b a r) d= 280 cm d= 270 cm d= 260 cm d= 250 cm d= 240 cm d= 230 cm d= 220 cm g.a.r.rassoul, and omar m. waheeb ijcpe vol.11 no.2 (june 2010) 33 references 1. j jayskera, and s. g good years., "the development of heavy oil field in united kingdom continental shelf past present and future". this paper prepared by petroleum engineering society (1999). 2. edward g. stokes, marshall h. mitchael and dennis t. perry., "a method of controlling oil production from gas lift production well system" patent no. us 703762, (2000). 3. frick thomas c., "petroleum production hand book" vol ii new york mcgraw hill book co (1958). 4. j. wardlly smith., "the control of oil pollution on the sea and inland waters" graham and trotman lted (1979). 5. kishore k mohanty., "development of shallow viscous oil reverse in north slope". quartly progress report by department of chemical engineering university of huston (2003). 6. kermit e. brown., "the technology of artificial lift method" ppc books tulsa (1977). 7. mayron khulman., "boosting oil recovery" al manhal petroleum development magazine (2005). 8. salmon levy, "two phase flow in complex systems” john willey & sons, inc (1999). 9. t. e. w. nind., "principles of oil well production", mcgraw hill books co (1964). 10. tom reid, and bartlesiville o. k., "study of hydrocarbon miscible solvent slug injection process for improved recovery of heavy oil from sharder bluff pool miln point unit, alaska" prepared by petroleum development laboratory university of alaska (1994). iraqi journal of chemical and petroleum engineering vol.17 no.4 (december 2016) 1123 issn: 1997-4884 synthesis of nano ni-mo/γ-al2o3 catalyst abdul-halim a. k. mohamed* and hawraa h. atta chemical engineering department – college of engineering – university of baghdad (iraq) * email: prof.abdulhaleem@gmail.com abstract nano γ-al2o3 support was prepared by co-precipitation method by using different calcination temperatures (550, 600, and 750) o c. then nano nimo/γ-al2o3 catalyst was prepared by impregnation method were nickel carbonate (source of ni) and ammonium paramolybdate (source of mo) on the best prepared nano γ-al2o3 support at calcination temperature 550 o c. make the characterizations for prepared nano γ-al2o3 support at different temperatures and for nano nimo/γ-al2o3 catalyst like x-ray diffraction, x-ray fluorescent, afm, sem, bet surface area, and pore volume. the ni and mo percentages in the prepared nano nimo/γ-al2o3 catalyst determined by x-ray fluorescence were 2.924 wt % and 12.9 wt %, respectively. sem of prepared nano γ-al2o3 support at calcination temperature 550 o c. the average particles diameter of prepared γ-al2o3 support determined by afm at calcination temperatures 550, 600, and 750 o c and for prepared nano nimo/γ-al2o3 catalyst at calcination temperature 550 o c. key words: nanoparticles, γ-al2o3, nimo/ γ-al2o3, co-precipitation method. introduction gamma al2o3 is one of the important ceramic materials which are mostly used as adsorbent, catalyst, and catalyst support because its thermal, chemical, and mechanical stability. for use as catalyst or adsorbent alumina with desirable characteristics such as high surface area, and small particle size is required [1]. morphology of synthetic gamma alumina can be changed by varying some of the reaction conditions such as: temperature, pressure, reaction time, thermal decomposition routes and methods of preparation, precursors, and reactants. the catalytic properties of gamma alumina depend on its physical properties such as surface acidity, porosity, and pore size of particles [2]. alumina is a chemical compound with melting point of 2072 °c and specific gravity of 3.4. alumina is insoluble in water and organic liquids and very slightly soluble in strong acids and alkalies [3]. alumina occurs in two crystalline forms. alpha alumina is composed of colorless spherical crystals shape. while gamma alumina is composed of minute colorless non spherical or irregular hexagonal crystals shape depending on the arrangement of oxygen anions [4]. university of baghdad college of engineering iraqi journal of chemical and petroleum engineering mailto:prof.abdulhaleem@gmail.com synthesis of nano ni-mo/γ-al2o3 catalyst 12 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net the gamma phase is transform to the alpha form at high temperatures [3]. also when high pressure the transformation is used, phase transformation occurs at low temperature. for example the phase of gamma alumina can be transformed to alpha alumina by changing temperature from750 to 1000 o c at 1 atm. but when increase the pressure from 1 atm to 8 gpa, gamma alumina transforms phase to alpha alumina at 460 o c because the high pressure decrease the thermodynamic energy barrier, and kinetic energy barrier required for nucleation also causes the phase transformation. high pressure caused enough number of nucleation sites to prevent the formation of the vermicular structure and take the equiaxed structure. the transition phase and temperature depend on the particles size chemical homogeneity, heating rate, and water vapor pressure [4]. the mechanical properties of gamma alumina depend on their nanostructure which are related with the shape, and size of the alumina particles. alumina has many advantages: hard, highly resistance towards bases and acid, very high temperature application, and excellent wear resistance [5]. the phase of alpha alumina with microsize is more stable than gamma alumina phase, while the phase of gamma alumina in nano structure is more stable than alpha alumina. this is because of the change in the thermodynamic stability with the size of nano particle [6]. potdar, et al., (2007) prepared nano sized γ-al2o3 by precipitation / digestion method at calcination temperature 550 o c. the surface area of obtained nano alumina was 220 m 2 /g and the average pore diameter was 4.5 nm [7]. y. i. tian-hong, el at., (2009) used precipitation method to prepare nano alumina at calcination temperature 450 o c and ph range 8 to 9. the surface area of obtained nano alumina was 269.9 m 2 /g, the pore volume was 0.57 ml/g, with range of size from 40 to 50 nm [8]. parida, et al., (2009) prepared nano spherical shape γ-al2o3 by control precipitation method at calcination temperature 550 o c. the surface area of prepared catalyst was 190 m 2 /g and the crystallite size was 5.7 nm [9]. mandan, et al., (2010) prepared nano sized γ-al2o3 by sol gel method at calcination temperature 600 o c. the surface area of obtained catalyst, the pore volume, and the average pore diameter were 242.9 m 2 /g , 1.42 cm 3 /g, and 16.5 nm respectively [10]. sarah, et al., (2012) prepared nano sized γal2o3 by sol-gel method at calcination temperature 500 o c. the surface area of obtained gamma alumina was 197 m 2 /g, the pore volume was 0.38 cm 3 /g and the average pore diameter was 8.6 nm [11]. asencios, et al., (2012) prepared nano sized γ-al2o3 by precipitation method at calcination temperature 500 o c. the surface area of prepared gamma alumina was 371 m 2 /g, while the ph was 6, the pore volume was 0.275 cm 3 /g, and the average pore diameter was 4.5 nm [12]. s.y. hosseini, et al., (2012) prepared nano γ-al2o3 catalyst powder by precipitation/digestion method at calcination temperature 580 o c for 5 h 1 in air. the obtained gamma alumina surface area, average pore diameter and total pore volume are 251 m 2 /g, 8.95 nm and 0.82 cm 3 /g, respectively [13]. a. rajaeiyan, et al., (2013) prepared nanostructured gamma alumina powder by sol gel and coprecipitation methods at 750 o c. the surface area of prepared sample by sol gel method was 30.72 m 2 /g and pore diameter was 49.09 nm, while the surface area of the prepared sample by precipitation method, and the pore http://www.iasj.net/ abdul-halim a. k. mohamed and hawraa h. atta -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 13 diameter were 206.2 m 2 /g, and 7.31 nm, respectively [14]. m. edrissi, et al., (2013) prepared nano sized alumina by combustion synthesis. the surface area of prepared nano alumina and average pore diameter were 154m 2 /g, and 10 nm respectively (15) . ferechteh rashidi, et al., (2013) prepared nano γ-al2o3 support by solgel method. the obtained nano γal2o3 with surface area 404.05 m 2 /g , pore volume 1.06 cm 3 /g and average size 10.469 nm. hds catalyst was prepared by wet co-impregnation method with percentage of 3% co, 13 % ni, and 3 % p on prepared γ-al2o3. the surface area of obtained catalyst was 295.63 m 2 /g, the pore volume was 0.62 cm 3 /g, and the average pore diameter was 8.355 nm. this catalyst used for hds diesel fuel which decreased the sulfur content from 150 ppm to 38 ppm [16]. a. eliassi, et al., (2014) prepared nanosized γ-al2o3 with surface area 413 m 2 /g, average pore diameter 38 nm and pore volume 1.624 cm 3 /g by using precipitation/digestion method. this catalyst used for methanol dehydration to dimethyl ether using fixed bed microreactor. the operation conditions were lhsv from 20 to 50 h -1 and temperature from 250 to 300 o c [17]. the aim of this work is to prepare nano gamma alumina then use it in the preparation of nano ni-mo/γal2o3 catalyst which can be used for hydrodesulphurization of iraqi gas oil. experimental synthesis of alumina by coprecipitation method 1 m of alcl3 was dissolved in 300 ml ethanol and 90 ml distilled water was added to get a transparent solution, then 120 ml nh3 was added to the stirred alcl3.6h2o solution drop by drop with the rate of 2.5 ml/min until the precipitate became white as al 3+ gel hydroxides was formed. after gel filtering in vacuum system, it was dried at 80 °c over night in the oven, and calcinated at 550 °c, 600 °c for 2 h, and 750 °c for 1 h. a white fine alumina nano-powder was obtained. synthesis of nano ni-mo/γ-al2o3 catalyst the ni-mo/γ-al2o3 catalyst was prepared by impregnation method. the device used for impregnation consisted of a conical flask with a separating funnel, vacuum pump, electric shaker and trap to absorb the moisture and gases (figure 1). an impregnated aqueous solution was prepared by dissolving 2.7 g nickel carbonate, 4.2 g of ammonium para molybdate and 25 ml of distilled water with mixing at room temperature. this solution was poured in the conical flask of the impregnation apparatus which contains 15 g of dried nano gamma alumina. the impregnation took place drop by drop for 1.5 hours. the impregnated nano alumina was air dried at 80 °c for 16 hours and then calcined at 550 °c for 16 hours. fig. 1: the device used for impregnation results and discussion xrd analysis and xrf analysis x-ray diffraction analysis for the samples was carried out using rigaku x-ray diffractometer with cukα radiation under identical conditions. these conditions are: http://www.iasj.net/ synthesis of nano ni-mo/γ-al2o3 catalyst 14 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net wavelength (λ) = 1.5406 a 0 , tube voltage = 40 kv, tube current = 30 ma, and scan range: 10 – 70 (deg). the xrd spectrum gives the diffraction intensity verses 2θ plot. the xrd spectra of prepared nano alumina at different temperatures are shown in the figures 2 4, while the xrd spectrum standard of gamma alumina is shown in figure 5. the comparison of xrd spectra with standard spectrum shows that all peaks of prepared support approached the standard gamma alumina. this means that the prepared support at different temperatures is gamma alumina. the difference in the height of obtained peaks may be due to the change in the calcination temperature used during support preparation. this mean the prepared support is nano gamma alumina because of that the peaks is more wide than the standard peas. fig. 2: the xrd spectrum for prepared nano gamma alumina at calcination temperature 550 o c fig. 3: the xrd spectrum for prepared nano gamma alumina at calcination temperature 600 o c fig. 4: the xrd spectrum for prepared nano gamma alumina at calcination temperature 750 o c http://www.iasj.net/ abdul-halim a. k. mohamed and hawraa h. atta -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 15 fig. 5: the xrd spectrum of synthetic of standard gamma alumina the purity of solid crystal was measured by comparing the x-ray diffractogram pattern of prepared nano alumina at different calcination temperatures with x-ray diffractogram pattern of standard gamma alumina shown in table 1. this comparison proved that the prepared gamma alumina at calcination temperature 550 o c is more nearly to the standard. the xrf analysis was used to find the percentage of ni and mo in the prepared catalyst. the percentages of ni and mo were 2.924 wt % and 12.920 wt %, respectively. the concentration of the metals on the support usually varies from 8 to 25 % for the active metal (mo) and from 1 to 4 % for the promoter (ni or co) [20]. the percentage of ni and mo in prepared nano catalysts are not far from those obtained by sandeep badoga,el at., (2014), who prepared mesoporous nimo/γ-al2o3 by using the sequential impregnation (3% ni, 13% mo). table 1: comparison between prepared nano gamma alumina at different calcination temperatures and standard synthetic gamma alumina gamma alumina 550 o c gamma alumina 600 o c gamma alumina 750 o c standard gamma alumina angle (2ɵ) deg d,spacing (å) angle (2ɵ) deg d,spacing (å) angle (2ɵ) deg d,spacing (å) angle (2ɵ) deg d,spacing (å) 20.462 4.33 20.000 4.43 21.246 4.18 20.494 4.33 31.641 2.82 31.691 2.82 31.728 2.81 31.936 2.80 37.486 2.39 37.385 2.40 37.323 2.40 37.603 2.39 39.521 2.28 39.434 2.28 39.492 2.27 39.401 2.28 45.930 1.97 45.930 1.97 45.905 1.98 45.764 1.98 60.349 1.53 60.224 1.53 59.974 1.54 60.457 1.53 66.422 1.40 66.827 1.39 66.688 1.40 66.761 1.40 atomic force microscopy (afm) the morphology of prepared alumina was studied using atomic force microscope. figures 6 – 8 show the images of afm on twodimensional surface profile at different calcination temperatures, while figures 9 11 show afm images for threedimensional surface profile at different calcination temperature. the two dimensional surface images in figures 6 8 show the irregular hexagonal structure of the gamma alumina crystal. three dimensional surface http://www.iasj.net/ synthesis of nano ni-mo/γ-al2o3 catalyst 16 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net images shown in figures 9 11 indicate that the agglomerates of gamma alumina nano crystal are in form of irregular hexagonal layers with height terraces up to 9.8 nm [5]. fig. 6: afm on two-dimensional surface of prepared nano alumina at calcination temp. 550 o c fig. 7: afm on two-dimensional surface of prepared nano alumina at calcination temp. 600 o c fig. 8: afm on two-dimensional surface of prepared nano alumina at calcination temp. 750 o c fig. 9: afm for three-dimensional surface of prepared nano alumina at calcination temp. 550 o c fig. 10: afm for three-dimensional surface of prepared nano alumina at calcination temp. 600 o c fig. 11: afm for three-dimensional surface of prepared nano alumina at calcination temp. 750 o c figures 12 – 14 show the particle size distribution for prepared gamma alumina at different calcination temperatures. at calcination temperature 550 o c the results confirm the largest volume percentage 19.27 % at 50 nm and the lowest volume percentage 0.36 % at 90 95 nm. the prepared gamma alumina at 550 o c consisted of particles with diameters ranged between 45 95 nm and average diameter of 56.91 nm this http://www.iasj.net/ abdul-halim a. k. mohamed and hawraa h. atta -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 17 result is near from that of a. rajaeiyan, et al., (2013), who prepared nano structured gamma alumina powder 49.09 nm [5]. while at 600 o c the results confirm the largest volume percentage 7.11 % at 55 nm and the lowest volume percentage 0.22 % at 99 100 nm. the prepared gamma alumina at 600 o c consisted of particles with diameters ranged between 15 180 nm and average diameter of 68.72 nm. at 750 o c the results confirm the most volume percentage 11.18 % at 105 nm and the lowest volume percentage 0.62 % at 45 nm. the prepared gamma alumina at 750 o c consisted of particles with diameters ranged between 45 105 nm and average diameter of 77.27 nm. fig. 12: bar chart of particle size distribution for prepared alumina at calcination temperature 550 o c fig. 13: bar chart of particle size distribution for prepared alumina at calcination temperature 600 o c fig. 14: bar chart of particle size distribution for prepared alumina at calcination temperature 750 o c http://www.iasj.net/ synthesis of nano ni-mo/γ-al2o3 catalyst 18 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net usually the range of nano particles is 1 – 100 nano meter [21]. figures 12 – 14 show that all prepared alumina support at different calcination temperature are nano type. it was observed that the average particle diameter of nano gamma alumina increase with the increase in calcination temperature. this is due to the crystal sentering [22]. the afm images of prepared nimo/γ-al2o3 catalyst using nano alumina support obtained at calcination temperature 550 o c are shown in figures 15 16. the two dimensional surface images in figure 15 show the irregular hexagonal structure of the gamma alumina crystal. three dimensional surface images shown in figure 16 indicating that the agglomerate of gamma alumina nano crystal are in form of irregular hexagonal layers with height terraces up to 3.96 nm [5]. figure 17 show the particle size distribution for prepared gamma alumina and these results confirm the largest volume percentage 23.85 % of particle size distribution 70 nm and the lowest volume percentage 5.38%, 85 nm. it also show the prepared gamma alumina consisted of particles with diameters ranged between 55 85 nm and average diameter was 64.74 nm. this means that the particle of prepared nano nimo/γ-al2o3 catalyst was nano type. the increasee in average particle diameter of prepared catalyst occurs due to loading ni and co during impregnation on prepared support and crystal centering during impregnation method [22]. fig. 15: for prepared nimo/γ-al2o3 afm image on two-dimensional surface profile at 550 o c fig. 16: for prepared nimo/γ-al2o3 afm for three-dimensional surface profile at 550 o c fig. 17: bar chart of particle size distribution for prepared nano nimo/γ-al2o3 catalyst at calcination temperature 550 o c http://www.iasj.net/ abdul-halim a. k. mohamed and hawraa h. atta -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 19 scanning electron microscopy (sem) sem images of prepared gamma alumina at calcination temperature 550 o c are shown in figure 18, at magnification of 50.00, 20.00, 47.90, 10.00, 4.00, and 3.00 k x. it is very convenient to compare the prepared gamma alumina crystal with that prepared by a. rajaeiyan, et al., (2013), as shown in figure 19. a.sem at a magnification of 4.00 kx b.sem at a magnification of 20.00 kx c.sem at a magnification of 50.00 kx d.sem at a magnification of 10.00 kx e.sem at a magnification of 606 x f.sem at a magnification of 3.00 kx fig. 18: sem images of prepared nano gamma alumina the comparison of sem images for prepared gamma alumina with sem for prepared nano gamma alumina by a. rajaeiyan, et al., (2013) shows that both gamma alumina are irregular hexagonal shape particles with uniform http://www.iasj.net/ synthesis of nano ni-mo/γ-al2o3 catalyst 20 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net distribution and has not strong agglomeration [5]. a.sem at a magnification of 47.90 kx of prepared gamma alumina b.sem at a magnification of 15.00 kx of prepared gamma alumina by a. rajaeiyan, fig. 19: sem images of prepared gamma alumina and nano gamma alumina prepared by a. rajaeiyan, et al., [5] general properties of catalyst physical and chemical properties of prepared catalyst at different calcinations temperature such as surface area, and pore volume were determined by bet device and presented in table 2. this table shows that the surface area decreased with increasing calcination temperature and maximum surface area 256.0 m 2 /g is obtained at calcination temperature 550 o c while the surface area of prepared nano gamma alumina by a. rajaeiyan, etal.,(2013) was 206.2 m 2 /g. the higher surface area usually has a high percentage of small pores [5]. also the using of high calcination temperature causes quick water evaporation from small pore to the large pore then to the bulk and this gives pressure drop. this pressure drop collapses part of pores especially in hydrogel step resulting in partial loss of surface area [9]. the pore volume of γ-al2o3 decreases with the increase in calcination temperature increasing and the minimum pore volume 0.3742 cm 3 /g obtained at calcination temperature 550 o c which was not far from 0.467 cm 3 /g obtained by parida et al. (2009) [1]. this occurs because high calcination temperature increases the reaction temperature, which rapidly leads the crystallites to contact each other. the contact occurs by two smaller crystallites agitated at higher temperatures resulting in coalescing to a larger one causing an increase of the pore volume and decrease the surface area by sintering or agglomeration of crystallites [9]. table 5: physical properties of prepared nano support γ-al2o3 calcined temp o c surface area m 2 /g pore volume cm 3 /g pore volume distribution nm 550 256.0 0.3742 5 600 217.5 0.3715 750 213.5 0.4123 the prepared nano ni-mo/ɣal2o3 catalyst obtained at calcination temperature 550 o c has surface area 215.82 m 2 /g, and pore volume 0.2855 cm 3 /g which was near that by sandeep badoga,el at., (2014) who prepared nano ni-mo/ɣ-al2o3 catalyst with surface area of 225 m 2 /g . the decrease http://www.iasj.net/ abdul-halim a. k. mohamed and hawraa h. atta -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 21 in surface area, and pore volume may be due to blockage of some pores by impregnation of ni and mo on the prepared support [21]. conclusion nano γ-al2o3 support was prepared by co-precipitation method from aluminum chloride as a source of alumina and ammonia hydroxide by using different calcination temperatures 550, 600, and 750 o c. from x-ray diffraction pattern and when compared it with the standard of gamma alumina found that prepared supports at different temperatures are mainly gamma alumina. bet test found the surface area of prepared nano gamma alumina at 550, 600, and 750 o c are 256, 217, 213 m 2 /g. the decreasing in surface area occur by increasing temperature. from atomic force microscopy test found that the average diameter of particles of prepared gamma alumina is 56.91 nm at 550 o c, 68.72 nm at 600 o c and 77.27 nm at 750 o c. while the average diameter of particles of prepared nimo/γ-al2o3 catalyst is 64.74 nm, and this means that the prepared γ-al2o3 support and the prepared nimo/γ-al2o3 catalyst are in the range of nano type 1-100 nm. references 1. mohamed reza n. "empirical modeling of nano alumina combustion synthesis using boxbehnken statistical desiden", 15875-4413, 2013. 2. a. eliassi, m. ranjbar, "application of novel gamma alumina nanostructure for preparation of dimethyl ether from methanol", vd.10, no.1, pp.13-26., mar, 2014. 3. carvill, b. t. and l. t. thompson, "hydrodesulfurazation over model sulfide cluster-derived catalysts", applied catalysis. 75, 249-265, 1991. 4. lioa, s. c., chen, y. j., kear, b. h., and mayo, w. e., "high pressure low temperature sintering of nano crystalline alumina nano structured materials", 10 (60). 1998. 5. a. rajaeiyan, m. m. bagherimohaghi, "comparison of solgel and co-precipitation methods on the structural properties and phase transformation of γ and α-al2o3 nanoparticales", springer, 1: 176182, 11. may, 2013. 6. philippe serp. and karine philippot., "nano materials in catalysis", first edition, 2013. 7. potdar h. s., jun k. w., kim s.m., lee y. j., "synthesis of nanosized porous γ-al2o3 powder via a precipitation didstion roate", app catal, a 321:109-116. 8. y. i. jian – hong, sun youyi., x. v. chun-yan, "synthesis of crystalline γ-al2o3 with high purity", elsevier, jan., 2009. 9. james t. richardson, "principles of catalyst development", peg 29143. 10. mandan akai, seyed mahdi alavi, and zi-feng yan. "promoted platinum dehydrogenation catalyst on a nano-sized gamma alumina support", petroleum & coal, 15, oct., 2010. 11. sarah hartmann, alexander sachse, and anne galarneau, "challenges and strategies in the synthesis of mesoporous alumina powders and hierarchical alumina monoliths", materials, 20 feb., 2012. 12. yvan j. o. asencios, and maria r. sun-kou, "synthesis of highsurface area γ-al2o3 from aluminum scrap and its use for the adsorption of metals: pd (ii), cd (ii), and zn (ii)", sibi, 26, june., 2012. 13. s. y. hosseini, and m. r. khosravi nikon, "synthesis and http://www.iasj.net/ synthesis of nano ni-mo/γ-al2o3 catalyst 22 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net characterization of nano-sized γal2o3 catalyst for production of dimethyl ether via indirect method", icns4, 14, march, 2012. 14. i. s. seyed ali hosseini, aligholi niaei, and dariush salari, "production of γ-al2o3 from kaolin", scientific research, 12, july, 2011. 15. mohamed edrissi, and reza norouzbeigi, "empirical modeling of nano alumina combustion synthesis using box-behnken statistical design", www.tandfonline.con/lio/lsrt20, 02, des., 2013. 16. fereshteh rashidi, takehiko ali morad rashidi, ali nemati kharat, and kheirollah jafari jozani, "ultra deep hydrodesulfurization of diesel fuels using highly efficient nano alumina-supported catalyst: impact of support, phosphours, and/or boron on the structure and catalytic activity", elsevier, 4 feb., 2013. 17. sandeep badoga, rajesh v. sharma, ajay k. dalai, and john adjaye, " hydrotreating of heavy gas oil on mesoporous mixed metal oxides (m-al2o3, m=tio2, zro2, sno2) supported nimo catalyst: influence of surface acidity", int. j. nanosci. nanotechnol, no1, vol. 10, 12 may, 2014. 18. jinto manjaly anthony kutty, "hydrotreating of tall oils on a sulfied nimo catalyst for the production of base – chemicals in steam crackers", 24 th of april, 2015. 19. syed tajammal hussain, and farzana zia, "modified nano supported catalyst for selective catalytic hydrogenation of edible oils", springer, 18 des., 2008. 20. luisa filipponi, and duncon suther land, " nano technologies principles, application, implication, and hand-on activities", pag 19, 2013. 21. ghanbari k., "petroleum and coal", elsevier, 28(2)33-36, 2006. http://www.iasj.net/ http://www.tandfonline.con/lio/lsrt20 abdul-halim a. k. mohamed and hawraa h. atta -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 23 appendix (a) spectro x-labpro job number: 0 description hawraa method turboquant-powders sample name 3 date of receipt 05/27/2015 11:56:06 z symbol element norm. int concentration abs. error 12 mgo magnesium 38.0224 0.927 % 0.027 % 13 al2o3 aluminum 12382.5502 79.85 % 0.066 % 14 sio2 silicon 66.3879 0.2311 % 0.0051 % 15 p2o5 phosphorus 254.9972 0.3699 % 0.0039 % 16 so3 sulfur 0.0000 < 0.00050 % (0.0) % 17 cl chlorine 428.9963 0.06085 % 0.00036 % 19 k2o potassium 6.5734 0.0374 % 0.0026 % 20 cao calcium 31.9450 0.1230 % 0.0023 % 22 tio2 titanium 0.0000 < 0.00034 % (0.0) % 23 v2o5 vanadium 0.0000 < 0.00037 % (0.0037) % 24 cr2o3 chromium 0.0000 < 0.00015 % (0.0) % 25 mno manganese 7.2168 0.00373 % 0.00034 % 26 fe2o3 iron 205.1929 0.06025 % 0.00040 % 27 coo cobalt 96.6807 0.1328 % 0.0087 % 28 nio nickel 19686.3359 2.924 % 0.002 % 29 cuo copper 40.2948 0.00447 % 0.00022 % 30 zno zinc 2537.4834 0.2390 % 0.0004 % 31 ga gallium 0.0000 < 0.00005 % (0.0) % 32 ge germanium 0.0000 < 0.00005 % (0.0) % 33 as2o3 arsenic 0.0000 < 0.00007 % (0.0) % 34 se selenium 0.0000 < 0.00005 % (0.0) % 35 br bromine 10.9351 0.00032 % 0.00002 % 37 rb2o rubidium 56.4448 0.00108 % 0.00002 % 38 sro strontium 439.2818 0.00821 % 0.00004 % 39 y yttrium 9.5877 0.00015 % 0.00003 % 40 zro2 zirconium 44.4298 0.01603 % 0.00033 % 41 nb2o3 niobium 45.5775 0.01384 % 0.00053 % 42 mo molybdenum 40962.1338 12.92 % 0.01 % 47 ag silver 1.3400 0.00183 % 0.00055 % 48 cd cadmium 8.6726 0.00797 % 0.0004 % 50 sno2 tin 12.2892 0.01152 % 0.00041 % 51 sb2o5 antimony 9.2371 0.01027 % 0.00048 % 52 te tellurium 11.0299 0.00700 % 0.00030 % 53 i iodine 7.0907 0.00644 % 0.00067 % 55 cs cesium 0.0000 < 0.00040 % (0.0) % 56 ba barium 0.0000 < 0.00020 % (0.0) % 57 la lanthanum 3.8772 0.00188 % 0.00046 % 58 ce cerium 0.0000 < 0.00020 % (0.0) % 72 hf hafnium 34.4012 0.00660 % 0.00019 % 73 ta2o5 tantalum 141.1496 0.0344 % 0.0011 % 74 wo3 tungsten 21.4133 0.00436 % 0.00094 % 80 hg mercury 0.0000 < 0.00010 % (0.0) % 81 tl thallium 15.2258 0.00058 % 0.00003 % 82 pbo lead 735.5520 0.05019 % 0.00016 % 83 bi bismuth 0.0000 < 0.00010 % 0.00047 % 90 th thorium 21.5463 0.00100 % 0.00005 % 92 u uranium 18.5451 0.00047 % 0.00002 % sum of concentration 54.88 % http://www.iasj.net/ iraqi journal of chemical and petroleum engineering vol.16 no.2 (june 2015) 3944 issn: 1997-4884 using the artificial gas lift to increase the productivity of noor oil field / mishrif formation talib a. salh * , safaa h. sahi ** and shaymaa a. hussein ismael * * university of baghdad, collage of engineering, petroleum department ** ministry of oil, reservoir and field development office abstract noor oil field is one of iraqi oil fields located in missan province / amarah city. this field is not subjected to licensing rounds, but depends on the national effort of missan oil company. the first two wells in the field were drilled in seventies and were not opened to production until 2009. the aim of this study is to study the possibility of using the method of gas lift to increase the productivity of this field . prosper software was used to design the continuous gas lift by using maximum production rate in the design. the design was made after comparing the measured pressure with the calculated pressure, this comparison show that the method of beggs-brill and petroleum expert2 gave the best results; therefore, these correlations have been adopted in the design of gas lift. the point of gas injection had been selected; the optimum gas injection rate, the maximum oil production rate, the number of valves required for gas injection and their depth, the pressure required to open and close each valve were calculated. the effect of water-cut, change the amount of ratio of gas to oil and decline reservoir pressure in natural flow case and gas lift method case were studied. the results of gas lift design show that the maximum oil production rate is (1000) stb/day and the optimum gas injection rate (2.65) mm scf/day at using operating pressure of (0011) psi available at casing head and the minimum bottom hole following pressure is (1501.5) psi. key words: artificial gas, noor oil field introduction when oil is first exist in the reservoir, it is under pressure from the natural forces that surround and trap it. if a well is drilled into the reservoir, an opening is provided at a much lower pressure through which the fluid can escape. the driving force which causes the fluid to move out of the reservoir and into the wellbore comes from the compression of the fluids that are stored in the reservoir. the actual energy that causes a well to produce oil results from a reduction in pressure between the reservoir and the producing facility on the surface [1]. if the pressures in the wellbore and the reservoir are allowed to equalize, either because of a decrease in reservoir pressure or an increase in iraqi journal of chemical and petroleum engineering university of baghdad college of engineering using the artificial gas lift to increase the productivity of noor oil field / mishrif formation 40 ijcpe vol.16 no.2 (june 2015) -available online at: www.iasj.net wellbore and surface pressure, there will be no flow from the reservoir and hence no production from the well.[2] there are a number of factors that affect the producing characteristics of an oil well. these factors are often interrelated and may include such things as fluid properties of the oil itself, amount of gas and water associated with the oil, properties of the reservoir, size of the producing pipe and related subsurface equipment. also the size and length of the flow line connecting the well to the production facilities are consider from factor that affect the producing characteristics . all of these factors play an important part in an oil well’s performance and most carefully considered when the installation is designed. [1] an ideal production installation makes maximum use of the natural energy available from the reservoir. in many wells the natural energy associated with the oil will not produce sufficient pressure differential between the reservoir and the wellbore to cause the well to flow into the production facilities at the surface. [1] there are basically four ways of producing an oil well by artificial lift. these are: gas lift, sucker rod pumping, electrical submersible pumping and subsurface hydraulic pumping. [3] the choice of the artificial lift system in a given well depends on some factors, primary among them, as far as gas lift is concerned, is the availability of lift gas, either as dissolved gas in the produced oil, or from an outside source, then gas lift is often an ideal selection for artificial lift. gas lift is the method of artificial lift that most closely resembles the natural flow process. there are basically two types of gas lift systems used in the oil industry, they are: continuous flow and intermittent flow. brief idea about noor field noor oil field is located in the south of iraq in missan governorate and about 4 kms west iranian border, 25 kms north halfaya field, 20 kms east of buzurgan field, 17 kms east of amara field.[4] noor structure is a gentle closed anticline fold extending north west-south east. the field is about 18 to 20 km in long and 5.5 to 7.5 km in width. the main reservoirs in the field are "mishrif" and "nahr umer" formation. the crude oil of "mishrif" formation has a gravity of about (23) api, this relatively low api gravity makes the natural of oil up the production string at some desired rate impractical. the formation is composed of limestone rocks with little shale. the total thickness of the formation is about (385 m) and it is divided in to four major units and four barriers depending on information obtain from ministry of oil. total number of wells were drilled in the field are 11 wells, eight wells are completed in mishrif reservoir and the rest are completed in nahr umer reservoir. the first well in the field (noor-1) was drilled on 2 july 1977 and completed on 22 february 1978, it reached a maximum depth of 4938m. the last wells in the field (noor-9), (noor-10) and (noor-12) had been drilled in 2013, but these wells were not put on stream up to now. the actual production from the field was started from two wells at february 2009 and reached to eight production wells. literature review historical development of gas allocation: mayhill [5] analyzed the relationship between the gas injection rate and the oil production rate, and called the curve a " gas lift lance curve". he defined the most efficient taliba.salh, safaa h. sahi and shaymaa a.hussein ismael -available online at: www.iasj.net ijcpe vol.16 no.2 (june 2015) 41 gas injection rate as rate at which an incremental expense for gas injection is equal to percentage of the incremental revenue produced at that gas injection. radden et al. [6] presented an analytical procedure to line the most profitable distribution of gas to wells in a continuous gas lift system. they developed a computer program to perform calculations for the gas allocation and it was successfully applied to a venezuela field for a group of thirty wells. gomez[7] proposed a procedure to generate the gas lift performance curve and also developed a computer program which fitted second degree polynomial to each gas lift performance curve by the least square method. this polynomial was then used to determine which would produce the largest amount of oil when equal amounts of incremental gas were injected into each well. this well would then be allocated this incremental amount of gas, and this procedure would be continued until all the available injection gas volume is used. hong [8] investigated the effects of several variables on continuous flow gas lift systems. he used a system consisting of six gas wells and surface flow lines, and optimized the system under the condition of variable well head pressures. the procedure for finding the optimum gas injection rate is basically the same as that proposed by gomez. however hong employed a cubic spline interpolation technique for the estimation of the gas lift performance curves. kanu et.al [9] established the method of equal slope allocation method under both unlimited and limited gas supplies. they presented the formulation of the economic slope and the use of this slope to allocate a total amount of gas at the optimal economic point for a group of wells in a step by step procedure. nishikiori et.al. [10] developed a new method for finding the optimum gas injection rate for a group of continuous gas-lift wells to maximize the total oil production rate. the new method was a quasinewton non-linear optimization technique, which is incorporated with the gradient projection method. a computer program is developed capable of implementing the new optimization method as well as generating the initial estimate of the gas injection rates. theoretical background vogel [11] developed an empirical technique for predicting well productivity's under such reduced condition and he called his method of analysis inflow performance relationship (ipr) and then used for wells producing from several fictitious solution gas drive reservoir from these curves he was able to develop a reference ipr curve which not only could be used for most solution gas drive reservoirs .however, good experience has been obtained using the vogel ipr in all twophase flow conditions. the vogel ipr dimensionless curve is based on the following equation:   0.1 max  o o q q 2 8.02.0                  r wf r wf p p p p … (1) the initial bubble point pressure (pb) can be substituted instead of the average reservoir pressure (pr) in the above equation to emphasize that the vogel ipr curve would be applied when pr > pb. flow regimes flow pattern or regimes frequently encountered in vertical two – phase flow are shown in figures (1) & (2). most investigators who consider flow regimes define four regimes which may occur in a vertical pipe. although using the artificial gas lift to increase the productivity of noor oil field / mishrif formation 42 ijcpe vol.16 no.2 (june 2015) -available online at: www.iasj.net different names are given these regimes, most of the methods discussed in this section use essentially the same description for these four flow regimes[12]. fig. 1, vertical flow patterns fig. 2, flow regime map modified beggs and brill method for single phase can be modified for multi-phase flow by considering the fluids to be homogeneous mixture[13]. thus: dl dv vg d vf dl dp    sin 2 2 … (2) where the definition for ρ and v can vary with different investigators. equation (2) shows that the total pressure drop for a two phase flow pipeline is the sum of the pressure losses due to: 1fluid friction effects, 2hydrostatic head effects, and 3kinetic energy or acceleration effects. thus: δpt =δp f + δp e + δp ke …(3) gas lift performance the (prosper) software, production and system performance, presented by petroleum experts limited’s had been adopted to match the real data and predict tubing and pipeline hydraulics. because the lack of sufficient information of mishrif reservoir/ noor oil field, well noor 2 was chosen for application artificial gas lift and is regarded as the rest of the wells in the field which need to apply the gas lift. [14] match the pvt to real data: black oil method had been used to determine the p.v.t properties and the main laboratorymeasured fluid properties that loaded into prosper software and used to get pvt match which were listed in table (1). table (1): data used to match pvt properties [14] property value solution gas oil ratio (scf/day) 620 gas gravity 0.76 water salinity (ppm) 180000 reservoir pressure (psi ) 5306.66 bubble point pressure (psi) 2626 oil f.v.f (rbbl/stb) 1.4246 @ pb oil viscosity (cp) 0.9 @ pb temperature 103 c º the correlations that match pvt properties were glaso correlation for bubble point (pb), gas oil ratio in solutions (rs) and formation volume (bo), beal et al correlation for oil viscosity property. the inflow performance (ipr): by using vogel’s equation to calculate pi value and the initial reservoir pressure which obtained from the well noor-2 test as input data in the software. these input data used to plotted ipr were: reservoir pressure taliba.salh, safaa h. sahi and shaymaa a.hussein ismael -available online at: www.iasj.net ijcpe vol.16 no.2 (june 2015) 43 was 5306.66 psi, pi equal to 1.88 (stb/day/ psi) and 0 % water-cut. figure (3) shows the ipr plot. pressure gradient match: when well head pressure and top of perforation depth have been available then pressure gradient can be plotted by prosper software. many correlation methods were used to make sure that they match the pressure gradient. as shown in figure (4) and (5), beggs-brill and petroleum experts-2 methods have a good gradient match. data that used to obtain the gradient match were: well head pressure 675 psi and top of perforation 3366 m. outflow performance (vlp): depending on pressure gradient match, beggsbrill and petroleum experts-2 methods were the best correlation method which used to represent vlp (vertical lift performance). as shown in figures (6) and (7), the intersection point between ipr and vlp represent the flowing bottom hole pressure and flow rate of the total system. gas lift design gas lift design –performance curve plot: according to design conditions; the maximum oil rate of well noor-2 could produce was 1000 stb/day with 2.65 mm scf/day of gas injected at optimum depth of injection, the maximum oil production shown in figure (8). gas lift design-the position of the operating and unloading valves: figure (9) display the position of the operating and unloading valves at final design condition and the plot of tubing and casing pressure gradients for the design rate. results and discussion to prove the efficiency of gas lift in the current research, a comparison made between natural flow and flow with gas lift for different water-cut 10%, 20%, 30 %, 40%, 50%, the calculations was carried out at surface operating pressure of 1700 psi for gas lift process. for example the case where the results show that the well noor-2 continue to produce when water-cut raise to 50%, reservoir pressure 5300 psi and the first node pressure 675 psi if gas lift process has been applied while this well cannot produce naturally at the same conditions, this case shown in figure (10). the main conclusions of the current study can be summarized as following: 1prosper software had been used to predict the vertical pressure-losses correlations as depending on the test of well noor-2, this software showed that the best correlations for noor wells are modified beggs – brill and petroleum expert 2. 2the correlations glaso correlation for bubble point ( pb ), gas oil ratio in solutions (rs) and formation volume (bo) also beal et al correlation for oil viscosity property gave a good matching. 3get an acceptable differences percent at the intersection point during vlp/ipr matching. 4the results have shown that the optimum gas injection rate equal to (2.65mscf/bbl) for well noor-2. 5the maximum oil production rate that can obtained from gas lift design is 1000( stb/day). 6the surface operating pressure, as pso had role to make the point of injection as deep as possible and to be able to injection the required amount of gas. 7the numbers and locations of gas lift valves are depending on operating gas injection pressure. using the artificial gas lift to increase the productivity of noor oil field / mishrif formation 44 ijcpe vol.16 no.2 (june 2015) -available online at: www.iasj.net nomenclature qo oil flow rate, bbl/ day. qo max maximum oil flow rate , bbl/ day. pwf flowing bottom hole pressure, psi. pr reservoir pressure, psi. δp t total pressure drop, psi. δp f pressure drop due to friction, psi. δp e pressure drop due to elevation, psi. δp ke pressure drop due to kinetic references 1american petroleum institute (api), ; "gas lift. book 6 of the vocational training series", (1978). 2brown, k.e. " the technology of artificial lift methods", penn well books, usa, vol. 4, (1984). 3enemarie, r. e. ;" factors affecting potential production rate and gas injection requirement for a gas injection requirement for a gas lift oil well " , b. eng .thesis. fut minna, (2008). 4ministry of oil by joint hyperion resources –ministry technical committee ; " noor field assess stage study-mishrif and nahr umer formations" , september (2007). 5mayhill, t.d.;"simplified method for gas-lift well problem identification and diagnosis", paper spe 5151: presented at the spe 49th annual full meeting, houston , tx, october (1974), pp. 6-9. 6radden, j.d.; sherman, t. a. g. ,.and blann, j. r.;"optimizing gas-lift systems", paper spe 5150: presented at the spe 49th annual fall meeting, houston , tx, october (1974 ) , pp. 6-9 . 7gomes, v. ;" optimization of continuous flow gas-lift systems", m.s. thesis, u. of tulsa , (1974) . 8hong, h.t.;" effect of the variable on optimization of continuous gas– lift system ", m.s. thesis ,u. of tulsa, (1975) . 9kanu, e.p. ,mach, j. and brown ,k.e.;" economic approach to oil production and gas allocation in continuous gas –lift ",spe ,october(1981), p. (1887) . 10nishikiori ,n.;"gas allocation optimization for continuous flow gas –lift system " ,m.s. thesis ,u .of tulsa ,(1989) . 11vogel, j.v.;" inflow performance relationship for solution gas drive wells", j. pet. tech., jun. (1968), pp. 83-92 : trans., 243. 12dr. james p. brill & dr. h. dale beggs; "two phase flow in pipe ", third edition ,april (1979). 13beggs, h.d. and brill, j.p.;"a study of two-phase flow in inclined pipes ", j. pet. tech., may(1973), pp. 607-617. 14shaymaa a. ismael; "using gas lift technology to increase productivity of noor oil/ field mishrif formation ", march (2014). iraqi journal of chemical and petroleum engineering vol.15 no.4 (december 2014) 1-8 issn: 1997-4884 comparison between electroplating and electroless on plastic surface qassim.j.m. slaiman and khlas a. slman chemical engineering department, college of engineering, al-nahrain university abstract we report a method of converting non-conductive plastic surfaces into conductive by plating either copper electroless or copper electroplating -carbon black containing bending agent onto perspex plastics . various approaches have been studied in order to comparing properties of the plated copper for two methods such as scanning electron microscopy (sem),thickness, roughness, porosity, tensile strength and elongation. the results show that the surface of electroplating was uniform, compact, and continuous and it had an obvious metallic sheen, while the surface of plated copper for electroless for it had many pores. also observed that the coating was composed of small cells. these cells have been deposited together closely. thick copper layer was deposited a(38μm ) electroplating while (5μm) for electroless plating tensile strength and elongation of copper electroplating became greater compared with copper electroless, whereas the roughness and porosity became smaller. the electroplating copper deposition process developed in this study may open up a new route of plating on plastics (pop) for printed circuit boards, electromagnetic interference shielding, and many other applications. keywords: copper electroless, electroplating methods, non-conductive surface plating, methods of copper deposition. introduction metallization of non-conductive surfaces is important in many industrial applications as it lowers cost, allows more flexibility in parts design, and reduces weight compared to its metal counterpart [1]. plating on plastics (pop) therefore has been developed and widely involved in manufacturing printed circuit boards (pcbs) and automobile parts, and in the electromagnetic interference (emi) shielding application [3]. having excellent electrical conductivity and being relatively inexpensive, copper (cu) has been widely studied for pop and a variety of plastics have been cu plated including acrylonitrile-butadiene styrene (abs), polypropene, and teflon [1]. currently, there are two technologies developed for cu plating of plastics, via the electroless route or through a direct electroplating route. for the first route, a regular electroless plating procedure is needed to place a thin conductive cu layer on the plastic surface. such a cu layer provides sufficiently high conductivity required for the subsequent electroplating to complete the materialization finishing. iraqi journal of chemical and petroleum engineering university of baghdad college of engineering comparison between electroplating and electroless on plastic surface 2 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net however, the involvement of a regular electroless plating operation in pop is not desirable because of the disadvantages associated with electroless plating, including the complexity of the plating bath, a time consuming procedure, and the use of costly catalyst and environmentally unfriendly agents [4]. alternatively, direct cu electroplating on plastics was proposed as a substitute to the electroless route, which involves an essential step of seeding the plastics surface with an electronically conductive catalyst or activator, typically a palladium (pd) and/or tin (sn) colloid. on adsorption of the catalyst onto the plastics surface, the seeded surface is subjected to a regular electroplating procedure to complete the metallization [10]. although many of the disadvantages associated with electroless plating have been circumvented by excluding this operation from the pop process, the requirement of costly catalyst for the direct electroplating is still undesirable. besides, many operations such as etching, neutralization, activation, and acceleration are needed before the electroplating starts, making the direct electroplating route a multi-step and time-consuming process.hence, elimination of the use of catalyst and development of simpler and more costefficient cu plating bath with a view to further optimize the pop procedure are desired. recognizing these, we studied and developed an alternative to electroless deposition of conductive cu on plastics by carbon processes utilize a suspension of carbon black particles to deposit a conductive layer of carbon onto the substrate surface. the coated plastics were then scoured and subjected to a simple electroless procedure in a bath of 30 g/l copper sulfate (cuso4) and 140 g/l complexing agent (edta). good conductivity was obtained at a 10-min deposition time and leveled off after 20 min. for comparison, carbon black (c) particles were prepared and applied to perspex as well, and subjected to the acid copper electroplating. it was found that incorporation of c particles into the paste shortened the time to reach the plateau conductivity and enhanced the adhesion of electrolessly deposited cu layer to the substrate surface. the electroplating deposition process developed in this study may open up a route of pop for pcb, emi shielding, and many other applications. experimental work materials the carbon black powder (particle size range 2–12 µm) supply from (lpkf leaser & electronics ag company), acetic acid from (tetenal – photo werk) germany, for copper sulfate supplied from (sojuz chiem export company,mosxww) sulphuric acid (98%) (gainland chemical company) and hcl (32%) (bdh company), perspex plastic board was supplied from (basf,germany co.) sample preparation the dimensions of the substrate (perspex) was 5*5 cm.substrate surface is at first roughened by mechanical roughening with abrasive paper. then the surface is rinsed and etched with 4% sulfuric acid for 2 min followed by rinsing. preparation of carbon coating carbon powder, bonding agent, and acitic acid were mixed and magnetically stirred vigorously for 30 min. carbon black were dispersed then applied on perspex boards that were pre-cut into 5*5 cm2 squares, and perspex was dipped into solution of carbon black for 5 min and then dried in air at 60 ˚c to be ready for the subsequent experiments (electroless copper deposition). for comparison, qassim.j.m. slaiman and khlas a. slman -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 3 with acid copper electroplating were also prepared by following the same preparation procedure on perspex boards. electroless copper plating after carbon activation, electroless copper plating was performed. the bath composition and condition of this work is listed in table 1. for the copper source, copper sulfate was used and for complexing agent, edta was used. the ph of the bath was fixed at the value of 12.8 which is reported by previous researchers to be a value where the deposition rate of copper is uniform. the selective deposition of electroless copper plating depends on the substrate and activation.the substrate was dipped into bath for15 min. initial experiments were performed to compare the plating profiles for a variety of copper electroless and electroplating. later tests were focused on plating thickness, roughness, porosity and tensile strength for surface. electroplating process the composition of the base electrolyte used in all plating tests is listed in table 2. the plating additives used were: suppressor, accelerator, leveler and chloride [4]. copper anodes were directly placed in a plating bath with a working volume of 5l. the substrate was dipped into bath for 15 min. table 1: composition of electro less cu bath chemical components conc. cupric sulphate (cuso4) g/l 30 formalin (hcho) ml/l 10ml/l complexing agent (edta) g/l 140 bath conditions ph adjuster naoh (12.8) naoh (12.8) temperature o c 25 table 2: composition of electroplating cu bath chemical components conc. cuso4•5h2o, g/l 200 h2so4, ml/l 50 bath conditions current density, a/dm 2 2 temperature, o c 25 measurement of metal deposition thickness of the surface and cross sectional morphologies were observed using optical microscope (om)(olympus bx-51) and scanning electron microscope (sem) [5]. measurement of mechanical properties tensile strength and elongation of plated copper were used in accordance with ipc tm-650, 2.4.18.1. vertical and horizontal pulls were measured. macro-roughness was determined over a 315micron range and 5 locations were averaged to determine the substrate roughness and 7 trials were performed at each location. porosity measured by saturated method such tests are designed to attack the substrate revealing the corrosion occurring through the pores (taylorhobson company). results and discussion surface morphology and thickness of the plating typical sem micrographs of copper electroplating at low and high magnifications are presented in figs.1 a and b, it can be observed that the surface of plated copper for electroplating , which was uniform, compact, and continuous and it had an obvious metallic sheen. typical sem micrographs of the opper elctroless at low and high magnifications are presented in figs.1 c and d, respectively. it can be observed that the surface had many pores. also observed that the coating was composed of small cells. these cells have been deposited together closely. comparison between electroplating and electroless on plastic surface 4 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net fig. 2 shows the copper plating thickness as a function of time, for the electro and electroless plating. the plating rate for electroplating increased linearly with time, while the electroless plating is locally suppressed. an excellent thickness was achieved at time 35 min for thickness (38μm) electroplating while (5μm) for electroless plating. increasing this time caused increasing of rate of decomposition for electroless plating. this possible reason was that the catalytic reactions were saturated when it was above 35min. while proved that plating thickness for electroplating depending on the current density of plating to achieve the required copper thickness on the plastic substrate. tensile strength and elongation the results from the tensile strength and elongation evaluation are given in fig. 3 it can be observed the tensile strength value for copper electroplating more than value for copper electro less plating. this possible reason was that increasing copper thickness on the plastic substrate plating over -potential increases the nucleation rate and leads to formation of deposits with higher tensile strength for electroplating. while electroless plating proved that the cu atoms were deposited far from them this lead to formation weak tensile strength [10]. roughness test the roughness value of copper electroplating and electroless were 0.65μm and 0.88 μm, respectively. the surface of copper electroplating was smooth comparing to the electroless the possible reason was that crystallographic planes and directions in crystal lattices of deposit more uniform than electroless deposition [11] porosity test the porosity value of copper electroplating and electroless were 1.5 and 3.28, respectively the porosity of copper plating depends on the method of deposition. electroless plating are noticeably more porous than electroplating plated. the possible reason was its surface has its slowest growing crystal planes in the plane of the substrate electrodeposits of copper, developed continuous films at an average thickness of less than 38μm on plastic substrates, whereas, electroless copper 5 μm or less in thickness were not continuous and showed many holes or channels as shown in fig. 4 [8]. conclusions 1. cu electroplating on perspex surface activation by carbon black was successfully with improved properties of plated copper coatings and the structure of the deposits was examined compared with cu electro less plating. 2. sem analysis showed that the surface of cu electroplating was uniform and continuous, while the pore structure of cu electro less could be still seen clearly. 3. a preliminary study of mechanical properties showed that the mechanical properties of cu electroplating and electro less exhibited as: the tensile strength and elongation was 51mpa, max force 2568 n and elong at max 5.54%, while the cu electro less was 47.8mpa, max. force 2448 and elong at max 4.83%, the thickness was (38μm) electroplating while (5μm) for electro less plating. the value of the porosity and surface roughness about 1.5 and 3.28for electro less and 0.65μm for electroplating and 0.88μm for electro less. this good indicated the cu electroplating was better than cu electro less for perspex surface. qassim.j.m. slaiman and khlas a. slman -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 5 fig.1: surface morphology of cu plating (a) sem hotograph cu electroplating (low magnifications) (b) sem photograph cu electroplating (high magnifications) (c) sem photograph cu electroless (low magnifications). (d) sem photograph cu electroless (high magnifications) fig. 2: copper thickness as a function of plating time for electro and electroless plating, for surface 4cmx4cm (a) stress (mpa) versus strain (%)for cu electro less comparison between electroplating and electroless on plastic surface 6 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net (b) force(n) versus extension(mm)for cu electro less (c) stress (mpa) versus strain (%) for cu electroplating qassim.j.m. slaiman and khlas a. slman -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 7 (d) ) force (n) versus extension (mm) for cu electroplating fig. 3: tensile strength of electroplating and electro less plated cu on perspx substrate fig. 4 relationship between porosity and thickness of copper deposited by electroplating and electroless substrate material was perspex and saturated test was used to measure porosity comparison between electroplating and electroless on plastic surface 8 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net references 1h. yanagimoto, s. dekia, k. akamatsu, k. gotoh,“selective electroless copper deposition on aluminum nitride substrate with patterned copper seed layer,” thinsolid films,vol. 491 (2005) pp. 18~22 2wei-ping dow, hsiang-hao chen, ming-yao yen, wei-hsiang chen, kao-hsuang hsu, po-yao chuang, hiroshiishizuka, nobuo sakagawa and ryoichi kimizuka, journal of the electrochemical society, 2008, 155, (12) pp. d750-d757. 3jia and wang "nickel-based activated carbon," bioresources5 (4), 2010. 4j. j. kelly, c. tian, and a. c. west, “leveling and microstructural effects of additives for copper electrodeposition,” j. electrochem. soc., vol. 146, no. 7 (1999) pp. 2540~2545 5charbonnier m, romand m et al (2006) copper metallization of polymers by a palladium-free electroless process. surf coat technol 200(18–19):5478 6deckert ca (1995) electroless copper plating a review. 1. plat surf finish 82(2):48 7ieee transactions on applied superconductivity, vol. 21, no. 3, june 2011 8surface & coatings technology 202 (2008) 5092–5102 9y. zhang, t. richardson, s. chung, c. wang, b. kim andc. rietmann, “fast copper plating process for 10 tsv fill,” proc. of 2007 international microsystems, packaging, assemblyand circuits technology conference, taipei,taiwan, oct. 2007, p.219222. 11yang ch, wang yy et al (1999) a kinetic study of direct copper plating via pd catalyst and s ligand. j electrochem soc 146(12): 4473 12ono s, naitoh k et al (1999) initial propagation stage of direct copper plating on non-conducting substrates. electrochimica acta 44(21–22):3697 iraqi journal of chemical and petroleum engineering vol.16 no.2 (june 2015) 18 issn: 1997-4884 modelling and optimization of carbon steel corrosion in co2 containing oilfield produced water in presence of hac aprael s. yaro and khalid h. rashid chemical engineering department – college of engineering – university of baghdadiraq abstract previously, many empirical models have been used to predict corrosion rates under different co2 corrosion parameters conditions. most of these models did not predict the corrosion rate exactly, besides it determined effects of variables by holding some variables constant and changing the values of other variables to obtain the regression model. as a result the experiments will be large and cost too much. in this paper response surface methodology (rsm) was proposed to optimize the experiments and reduce the experimental running. the experiments studied effects of temperature (40 – 60 °c), ph (3-5), acetic acid (hac) concentration (1000-3000 ppm) and rotation speed (1000-1500 rpm) on co2 corrosion performance of the regression model calculated by rsm. the experiments were conducted in saturated solution of co2 with 3.5 % nacl solution. statistica program version 10 was used for data analysis. in conclusion a quadratic model is proposed to predict the effect of mentioned variables in co2 environment. key words: co2 corrosion, regression analysis, optimization, carbon steel, corrosion rate, full factorial experimental design. introduction the major concern with co2 corrosion in oil and gas industry is that co2 can cause failure on the equipment due to the hydration to carbonic acid leading to a decrease in ph and initiating the co2 corrosion process. degree of corrosiveness due to co2 gas is influenced by environmental conditions such as; temperature, co2 partial pressure, corrosion film properties and flow conditions [1, 2]. many studied on co2 corrosion prediction and the effects of species like hac with several other operating conditions including above mentioned once had been published [3-5]. the simultaneous effects of many variables in the co2 corrosion could be optimized by using a statistical methodology such as design of experiment. in co2 corrosion, iron carbonate (feco3) film is the chief corrosion product formed and is formed through the reaction between carbonic acid, source of carbonate ions, (co3 -2 ) and iron (fe +2 ) released through corrosion of the pipeline. feco3 forms on the wall of the pipe if the product of ferrous ion concentration (fe +2 ) and carbonate ion concentration (co3 -2 ) exceeds the solubility product limit. the film is known to be protective and the corrosion rate drops once the film iraqi journal of chemical and petroleum engineering university of baghdad college of engineering modelling and optimization of carbon steel corrosion in co2 containing oilfield produced water in presence of hac 2 ijcpe vol.16 no.2 (june 2015) -available online at: www.iasj.net starts growing. although iron carbonate film formation mechanisms and kinetics have been extensively studied, it is not known how protective the film will be in the presence hac. moreover it is not known if the film failure (if any) is a result of a lower system ph or the result of interaction between corrosion products and hac. thus it becomes imperative to understand how feco3 precipitation is affected in the presence of hac, as also by the ph, temperature and ionic strength of the solution [6]. experimental work electrochemical set-up & specimen preparations a typical schematic three–electrode set-up used in all electrochemical experiments is shown in fig. (1). a rotating cylinder electrode with a speed control unit was used as the working electrode. fig.1, schematic corrosion test cell [7]. 1. potentiostat 6. co2 gas distributer 2. corrosion test cell 7. ammeter 3. reference electrode 8.voltmeter 4. counter electrode 9. hot plate 5. working electrode 10. co2 gas outlet glass cell was fitted with graphite electrode as auxiliary electrode and sce as a reference electrode. the working electrodes were api x65 carbon steel and the chemical composition is shown in table (1). the cylindrical specimens have diameter of 2.03 cm and 2.08 cm length with 0.13 cm thickness. before immersion, the specimen surfaces were polished successively with 220, 320, 400 and 600 grit sic paper, rinsed with methanol and degreased using acetone. the experiments were repeated at least twice in order to ensure reasonable reproducibility. table 1, composition of api x65 carbon steel in the experiments api x65 wt% c 0.15 si 0.24 mn 1.34 p 0.01 s 0.004 mo 0.10 fe balance cell solutions the experiments were performed both in stagnant and flow solution. the total pressure was 1 bar, the glass cell was filled with 1 liter of distilled water and 3.5% wt. nacl which was stirred with magnetic stirrer. the co2 gas (> 99.99 %) was bubbled through the cell (at least 1 hr prior to experiment) in order to saturate and de aerate the solutions. temperature was set using a hot plate. after the solution was prepared, the ph was adjusted to reach the ph set by using nahco3 and hcl, as buffer solutions. simulation of flow condition was conducted using rotating cylinder electrode (rce). a cylindrical working electrode was screwed on to an electrode holder at the center of the cell for rotating in the rce. the weight loss technique was used to measure the corrosion rate in gm/m 2 .day (gmd). co2 (1) (7) (10) (8) (6) (2) (4) (3) (5) (9) a v aprael s. yaro and khalid h. rashid -available online at: www.iasj.net ijcpe vol.16 no.2 (june 2015) 3 variable coding and experimental design two levels full factorial experimental design (ffed), with four variables, was used to study the response pattern and to determine the combined effect of variables. the effect of independent variables of t (°c), ph, hac concentration ca (ppm) and ω (rpm) is shown in table (3). the experiments number 17-20 were used to allow for estimating for a pure error of mean squares. the variables were coded according to the following equation [8]. where = coded value of an independent variable. = real value of an independent variable. table 2, shows the real and coded variables used in rsm study. real t (°c) ph hac (ppm) ω (rpm) code x1 x2 x3 x4 max. point +1 60 5 3000 1500 center point 0 50 4 2000 1250 min. point -1 40 3 1000 1000 table (3) shows a full factorial 2levels experimental design, with four variables (coded & real) was used to study response pattern & to determine the combination effects of variables. table 3, two-level full factorial experimental design of the independent variables with the observed, predicted values and absolute percentage error for the response. run no. coded factor response (gmd) error x1 x2 x3 x4 c.r exp. error 1 -1 -1 -1 -1 48.52 48.72 -0.20 0.41 2 +1 -1 -1 -1 121.30 121.78 -0.48 0.39 3 -1 +1 -1 -1 40.06 39.87 0.19 0.47 4 +1 +1 -1 -1 50.19 49.71 0.48 0.96 5 -1 -1 +1 -1 51.22 51.21 0.01 0.02 6 +1 -1 +1 -1 129.39 128.72 0.67 0.52 7 -1 +1 +1 -1 42.53 42.53 0.00 0.00 8 +1 +1 +1 -1 56.14 56.82 -0.68 1.21 9 -1 -1 -1 +1 52.65 52.76 -0.11 0.21 10 +1 -1 -1 +1 125.15 124.37 0.78 0.62 11 -1 +1 -1 +1 43.67 43.55 0.12 0.27 12 +1 +1 -1 +1 51.14 51.93 -0.79 1.54 13 -1 -1 +1 +1 55.69 55.38 0.31 0.56 14 +1 -1 +1 +1 130.46 131.43 -0.97 0.74 15 -1 +1 +1 +1 46.02 46.33 -0.31 0.67 16 +1 +1 +1 +1 60.14 59.16 0.98 1.63 17 0 0 0 0 63.81 61.15 2.66 4.17 18 0 0 0 0 59.72 61.15 -1.43 2.39 19 0 0 0 0 62.43 61.15 1.28 2.05 20 0 0 0 0 58.64 61.15 -2.51 4.28 the mean absolute percentage error modelling and optimization of carbon steel corrosion in co2 containing oilfield produced water in presence of hac 4 ijcpe vol.16 no.2 (june 2015) -available online at: www.iasj.net results and discussion fitting the model data from full factorial experimental design as given in table (3) was analysed by the least squares method to fit the second order polynomial model given the eq. (2), which represents an empirical relationship (in coded values and real units). where, t = temperature (°c) ph = acidity or strength of co2 saturated solution ca = concentration of hac (ppm) ω = rotation speed (rpm) statistical analyses it appears that the presented model significantly represents the data as described in table (4). table (4) shows the analysis of variance for corrosion in saturated co2 solution using full factorial experimental design (ffed) methodology. the main factors for the coefficient of the linear and square models shows significant value at confidence level of α = 0.05 (p < 0.5). however, for the interaction effect of the model is insignificant (p > 0.5) except for (t x ph). furthermore, the high value (99.99 %) of the correlation coefficient (r 2 ) for the responses suggests that the model is a good fit. table 4, analysis of variance (anova) for the fitted model const. estim d s o u rc e ∑x 2 estim. coeff. (b) variance sb 2 = sr 2 /∑ x 2 f-value = b 2 /sb 2 f0.95(1,5) = 6.61 b1 l in e a r 16 21.5 0.3 1685.9 s b2 16 -20.3 0.3 1503.9 s b3 16 2.4 0.3 21.6 s b4 16 1.6 0.3 9.3 s b11 s q u a re 16 1.9 0.3 14.1 s b22 16 1.9 0.3 14.1 s b33 16 1.9 0.3 14.1 s b44 16 1.9 0.3 14.1 s b12 in te ra c ti o n 16 -15.8 0.3 913.3 s b13 16 1.1 0.3 4.5 ns b14 16 -0.4 0.3 0.5 ns b23 16 0.04 0.3 0.01 ns b24 16 -0.1 0.3 0.03 ns b34 16 0.03 0.3 0.004 ns aprael s. yaro and khalid h. rashid -available online at: www.iasj.net ijcpe vol.16 no.2 (june 2015) 5 model adequacy checking the accuracy of any empirical model can also be done by means of statistical parameters, for example, correlation coefficient. the correlation coefficient (r 2 ) is a statistical measure of the strength of correlation between the predicted and measured values [9]. for the current problem, the following result is obtained: r 2 = 0.999 in presence of acetic acid (absence of the protective film formation) as shown in fig. (2). fig. 2, performance of the quadratic mathematical model for api x65 mild steel in presence of acetic acid (absence of protective film formation) graphic analysis of the model the aim of this study was to find a corrosion rate whose features would have been previously defined from the operative conditions extracted from the quadratic mathematical model. because the direct exploitation of the equation was delicate, it was convenient to restore it under a graphic representation; while fixing two of the four factors of the survey, it was possible to represent the response surface materializing the surface of regression in a three-dimensional space. it was also possible to project the equation in a design under isoresponse curves, interpreted as card curves level. fig. 3, response surface plot (top) and contour plot (bottom) showing the variation of response (corrosion rate) as a function of the temperature and ph at the optimum conditions (2178.5 ppm hac & 1296.6 rpm). (i) evolution of corrosion rate as a function of the temperature and the ph fig. (3) shows the evolution of the corrosion rate as a function of the temperature and the ph. it can be seen that the temperature has a strong influence on the tentative response. the minimal corrosion rate is obtained for a temperature of -0.5 in coded variable, i.e., 45.4 °c in real variable. considering simultaneous effects of temperature and ph is presented in fig. (3) contour plot. the figure shows, in low ph (ph 3), the increase of modelling and optimization of carbon steel corrosion in co2 containing oilfield produced water in presence of hac 6 ijcpe vol.16 no.2 (june 2015) -available online at: www.iasj.net corrosion rate is higher than in higher ph (ph 5). fig. 4 response surface plot (top) and contour plot (bottom) showing the variation of response (corrosion rate) as a function of the ph and hac acid concentration at the optimum conditions (45.4 °c & 1296.6 rpm (ii) evolution of corrosion rate as a function of the ph and hac acid concentration fig. (4), shows the synergism between the two factors: the ph and hac acid concentration in corrosion rate at temperature 45.4°c and speed of rotation of 1296.6 rpm. it can be noted that the effect of the hac acid concentration differed according to the corrosion rate’s variation. this effect becomes positive and even more important when the corrosion rate is degraded (reduced). analysis of corrosion rate as effects of interaction between ph and hac acetic concentration is shown in fig. (4) contour plot. the model shows an increase of corrosion rate due to hac. and the decrease of corrosion rate is caused by ph. fig. 5, response surface plot (top) and contour plot (bottom) showing the variation of response (corrosion rate) as a function of the temperature and speed of rotation at the optimum conditions (ph 4.8 & 2178.5 ppm). (iii) evolution of corrosion rate as a function of the temperature and speed of rotation fig. (5) represent the evolution of the corrosion rate as a function of the temperature and the speed of rotation. this figure shows that the corrosion rate decreased when the temperature decreased. this evolution was however more accentuated for the lower speeds of rotation. considering simultaneous > 80 < 76 < 66 < 56 < 46 < 36 2.8 3.0 3.2 3.4 3.6 3.8 4.0 4.2 4.4 4.6 4.8 5.0 5.2 ph 80 01 00 01 20 01 40 01 60 01 80 02 00 02 20 02 40 02 6 0 02 8 0 03 00 03 2 0 0 hac acid concentration (ppm ) 40 50 60 70 80 90 c o rro sio n r a te (g m d ) aprael s. yaro and khalid h. rashid -available online at: www.iasj.net ijcpe vol.16 no.2 (june 2015) 7 effects of temperature and speed of rotation is presented in fig. (5) contour plot. the figure shows, in high speed of rotation (1500 rpm), the increase of corrosion rate is higher than in lower speed of rotation (1000 rpm). (iv) evolution of corrosion rate as a function of the hac acid concentration and speed of rotation fig. (6), represent the evolution of the corrosion rate as a function of the hac acid concentration and the speed of rotation. this figure shows that the corrosion rate decreased when the hac acid concentration and speed of rotation decreased. 3d contour plot fig. 6 response surface plot (top) and contour plot (bottom) showing the variation of response (corrosion rate) as a function of the hac acid concentration and speed of rotation at the optimum conditions (45.4 °c & ph 4.8) this evolution was however more accentuated for the weakest and strongest concentrations in hac acid and the lessest and greatest effects of speed of rotation. fig. (6) contour plot presents a polynomial surface response relating to effect of hac and speed of rotation on corrosion rate. it is shown that different corrosion rate is observed for hac concentration and speed of rotation. speed of rotation increased corrosion rate from 26-38 gmd along the speed setting (1000-1500 rpm). hac concentration from 1000-3000 ppm has increased corrosion rate from 26-42 gmd. [10] and [11] have studied effects of speed of rotation on corrosion rate. they believed effects of mass transfer, hydrodynamic and diffusion coefficient that influenced corrosion rate. conclusions 1the second order polynomial regression analysis of the objective function (corrosion rate) describe the behavior of the process in absence of the protective film formation with mean absolute percentage error 1.2 % in terms of temperature, solution ph, hac acid concentration and speed of rotation. 2the corrosion rate of api x65 mild steel in co2 saturated, 3.5 wt% nacl solution in presence of acetic acid, increases with increasing temperature, acetic acid concentration and speed of rotation, and decreased with increasing of solution ph. 3the optimum conditions as predicted from eq. (2) are 45.4 °c, ph 4.8, 2178.5 ppm hac and 1296.6 rpm in absence of the protective film formation. 4the analysis of statistical full factorial experimental design (ffed), generally, shows that the square and interaction effects on the corrosion rate by weight loss modelling and optimization of carbon steel corrosion in co2 containing oilfield produced water in presence of hac 8 ijcpe vol.16 no.2 (june 2015) -available online at: www.iasj.net technique (within the studied range) is less pronounced compared with the main variables except the high interaction effect of (t x ph) in presence of acetic acid. 5the effect of the temperature, solution ph, hac acid concentration and speed of rotation on the corrosion rate in absence of the protective film formation in the following order: temperature > ph > hac acid conc. > speed of rotation references 1abd el-lateef, h.h., abbasov, v. m., aliyeva, l.i. and ismayilov, t.a., (2012), “corrosion protection of steel piplines against co2 corrosiona review”, chemistry, vol.2, issue 2, pp. 52-63. 2nesic, s., (2007), “key issues related to modelling of internal corrosion of oil and gas pipelines a review”, corrosion science, vol. 49, no. 12, pp. 4308-4338. 3zhang, g. and cheng, y., (2009), “on the fundamentals of electrochemical corrosion of x65 steel in co2-containing formation water in the presence of acetic acid in petroleum production”, corrosion science, no. 51, pp.8794. 4martin, c.f. and mokhtar, c.i., (2009), “effect of low concentration acetic acid on co2 corrosion in turbulent flow conditions”, corrosion, vol. 34, no. 12, pp.129-149. 5mokhtar, i.c., (2005), “prediction co2 corrosion with the presence of acetic acid”, ph.d. thesis, umist, united kingdom. 6sun, y., george, k. and nesic, s., (2003),“the effect of cl and acetic acid on localized co2 corrosion in wet gas flow”, corrosion, no. 3327, nace, houston, texas. 7rashid, k.h., (2014), “corrosion behavior of carbon steel in co2 – containing oilfield produced water”, ph.d. thesis, university of baghdad. 8box, g.e.p. and draper, n.r., (1987), “empirical model building and response surfaces”, john wiley & sons, new york. 9devore, p., (2005), “the exploration and analysis data”, 5 th edition, thomson learning, belmont, usa. 10silverman, d.c., (2005), “conditions for similarity of mass transfer coefficients and fluid shear stresses between the rotating cylinder electrode and pipe”, corrosion, no. 6, vol. 6, p.515. 11de waard, c., lotz, u. and dugstad, a., (1995), “influence of liquid flow velocity on co2 corrosion: a semi-empirical model”, corrosion, no. 128, nace, houston, texas. 1 1 iraqi journal of chemical and petroleum engineering vol.11 no.3 (september 2010) 1 7 issn: 1997-4884 corrosion of boiler tubes in south baghdad electric station dr. cecilia kh. haweel and janet lazar. chemical engineering department – college of engineering university of baghdad ______________________________________________________________________________________ abstract the corrosion of low carbon steel boiler tubes in demi water had been investigated. the purpose of this investigation was to determine the change produced in corrosion behavior of the carbon steel as a result of the specific presence of chloride and copper ions in the water under different temperatures. for low carbon steel experiments, the temperature was taken in three levels (125, 175, and 215°c) under about 27 bar pressure and 1500 rpm in autoclave. using weight loss technique, the corrosion rate ranges from (85 to 789 gmd) for low carbon steel boiler tubes. introduction corrosion can cause serious problem to the safe and economic operation of a wide variety of industrial installations. however, in order to understand a corrosion problem or situation, it is very important to be able to recognize the type of problem one is dealing with [1]. water is a naturally occurring substance; because except in rare cases it is not sufficiently pure, it cannot be used for human consumption or in industry without some form of treatment. the main use of water in industry is the transfer of heat and the production of steam. cooling water is used extensively in every manufacturing process, in fossil and nuclear, fueled steam plant and attendant steam generation dominate the power generating field [1]. water in the boiler section is heated to high temperature (260-315°c). the water is deaerated (usually by na2so3 addition) to reduce the o2 content less than (50 ppb) in a well operating boiler. some boilers are operated with zero solid water. high-purity water was used in the boiler; deaeration is obtained by adding volatile hydrazine or hydrazine replacement which is called carbohydrazid: a to control the ph and also reduce the o2 content [2]. carbon steel is widely used in chemical process plants for several important reasons. for one; it is low in cost, easy to fabricate, strong, and performance specifications are university of baghdad college of engineering iraqi journal of chemical and petroleum engineering corrosion of boiler tubes in south baghdad electric station 2 well defined. however, the general corrosion resistance of carbon steel is low in certain environment. most iron occurs naturally as stable oxide, and iron that had been processed into steel tend to return to that form [3]. iron and steel corrode in water to form various compounds depending upon the temperature and other environment conditions. theoretically, iron should react with water in the absence of air to form ferrous hydroxide: fe + 2h2o or (h+, oh-)  fe (oh) 2 + h2 however, even extremely small quantities of dissolved o2 in water will produce ferric ions which color the ferrous hydroxide to green. the up normal chemical control (i.e., ammonia dosing) and up normal operating conditions (i.e., steam and water velocities) may lead to a leakage in the condenser tubes causing dissolution of cu from the cu-ni alloy. drops of raw water may enter from the cooling side (tubes) to steam side (shell) holding contaminants (i.e., 22 2 4 o,sio,so,cl  , organic mater in addition of cu+2). so, this polluted water will enter the boiler where the corrosion problem will initiate because of high temperature (380 °c), and high pressure (60 bar). in this investigation, the interest lies in corrosion behavior of iron a widely used in the steam power plant with demi water as corrosive media. experimental work specimens preparation specimens of low carbon steel with dimensions of about (3 cm 1.5 cm) and (0.51 cm) thickness rectangular in shape were used exposing about 4.5 cm2 surface area to the corrosion media cleaning procedure specimens were cleaned by washing with detergent and flushed with tap water followed by deionized water, degreased by analar benzene and acetone, then annealed in vacuum at 600°c for 1 hour and cooled under vacuum to room temperature. finally, they were stored in a desicator over a silica gel to be used. specific treatment specimens carbon-steel were abraded in sequence using emery paper of grade number 220, 320, 400, and 600 then washed with running tap water followed by deionized water, then dried with clean tissue, degreased with benzene, dried, degreased with acetone, dried, and finally left to dry for one hour in a desicator over silica gel. weighing the specimens were carried out using 4 decimals digital balance and its dimensions were measured with a vernier. experimental procedure the tests were carried out using a standard reactor (autoclave) as shown in fig. (1) made of stainless steel and consist of pressure gauge and thermocouple which are sealed in stainless steel probe, internal agitator with stirring shaft hanged on it a specimen, safety pressure discs which protect the operator and the equipment from accidental destructive pressure. also consists of fitting for nitrogen feed. the carbon steel rectangular shape specimens were placed in taflon frame as shown in fig. (1) hanged on rotating shaft at constant speed of 1500 rpm in a reactor pressure vessel (autoclave) containing 250 ml of corrosive solution. before starting the experiment, the pressure was raised to 32 bar in the reactor for leakage checking by using pure nitrogen (98.0%), after that the pressure was reduced to the desired value of (i.e., 27 bar). dr. cecilia kh. haweel janet lazar 3 after they were exposed for one hour to the desired temperature of (125, 175, 215) °c and pressure of (27) bar. the specimens were cleaned with running tap water using a brush, followed by deionized water, dried with clean tissue, then degreased with benzene, dried, degreased with acetone, dried, left for one hour, then the weight loss was measured and the corrosion rate was obtained. fig (1) auto-clave system for corrosion rate measurement under high temperature and pressure results and discussion corrosion behavior of low carbon steel pipes used in boiler the influence of temperature (125, 175, and 215°c), chloride concentration as nacl (0.5, 50.25, and 100 ppm) beside copper concentration cu+2 (0.005, 0.0125, and 0.02 ppm), were studied using weight loss technique. the experiments were designed according to factorial method and 27 runs have been achieved as shown in table (1). it is important to mention here that the rotational mixer speed during the experiment was fixed at (1500 rpm) and the pressure at (271) bar. effect of temperature the rate of metallic corrosion is dependent on temperature like most chemical reactions. experiment at different temperatures and fixed flow velocity solution containing different concentration of  cl and cu+2 ions as nacl and cuso4.5h2o respectively, were carried on flow velocity was expressed as rotational mixer speed at 1500 rpm. fig. (2) shows the result of activation energies of low carbon steel obtained as log corrosion rates versus temperature reciprocal using arrhenius form, a linear relationship was obtained giving different activation energies (7.75, 4.58, 3.935, and 2.89 kcal/mol) depending on the  cl and cu+2 ions concentration in the solution. the values of activation energy (7.75 kcal/mol) indicates that at 0.5 ppm chloride and 0.005 ppm copper, the reaction is to some extent slow while when the copper concentration was increased to 0.02 ppm in the same time fixing the chloride concentration at 0.5 ppm, the reaction become faster (i.e. activation energy= 4.58 kcal/mole < 7.75 kcal/mole). some extent slow while when the copper concentration was increased to 0.02 ppm in the same time fixing the chloride concentration at 0.5 ppm, the reaction become faster (i.e. activation energy= 4.58 kcal/mole < 7.75 kcal/mole). fig. 2 arrhenius plot for the corrosion rate of low carbon steel at different concentration of chloride and copper ions 1.9 2.1 2.3 2.5 2.7 2.9 3.1 0.002 0.0021 0.0022 0.0023 0.0024 0.0025 0.0026 1/t(k -1 ) lo g ( c o rr o s io n r a te ), ( g m d ) linear (cl=0.5ppm, cu=0.005ppm) linear (cl=0.5ppm, cu=0.02ppm) linear (cl=100ppm, cu=0.005ppm) linear (cl=100ppm, cu=0.02ppm) corrosion of boiler tubes in south baghdad electric station 4 table (1) corrosion rate results of factorial experimental runs for the boiler. low carbon steel pipes achieved in the autoclave run no. temperature (°c) chloride (ppm) copper (ppm) c.r.* (gmd) 1 125 0.5 0.0050 85 2 125 0.5 0.0125 142 3 125 0.5 0.0200 213 4 125 50.25 0.0050 172 5 125 50.25 0.0125 230 6 125 50.25 0.0200 307 7 125 100 0.0050 266 8 125 100 0.0125 349 9 125 100 0.0200 401 10 175 0.5 0.0050 293 11 175 0.5 0.0125 341 12 175 0.5 0.0200 454 13 175 50.25 0.0050 382 14 175 50.25 0.0125 451 15 175 50.25 0.0200 513 16 175 100 0.0050 457 17 175 100 0.0125 524 18 175 100 0.0200 591 19 215 0.5 0.0050 506 20 215 0.5 0.125 595 21 215 0.5 0.0200 609 22 215 50.25 0.0050 591 23 215 50.25 0.0125 641 24 215 50.25 0.0200 721 25 215 100 0.0050 667 26 215 100 0.0125 739 27 215 100 0.02 789 * all corrosion rate valued in the last column are recorded from putting the sample in the corrosive media waiting until reaches the required temperature then 1 hr exposure time similarly, when the chloride concentration was increased to its maximum value. fixing the copper concentration at its minimum value, the reaction goes faster (i.e. 3.94 and 2.89 kcal/mol) indicating that chloride concentration leads the reaction to be under diffusion control. in the closed system as in this study no oxygen is permitted to escape. as a result of the rise in temperature, the corrosion rate increases steadily with the temperature. figs. (3 5) show the effect of increasing temperature on the corrosion rate of carbon steel pipes at different concentrations of  cl and cu+2 ions. it is clear that: 1. generally, the corrosion rate is higher as the  cl ions increases at different cu+2 ions concentration. 2. at all concentrations of  cl ions where the cu+2 increases the corrosion rate increase with the temperature. this can be attributed to cu+2 ions acting as cathode with respect to the carbon steel which act as anode. so, increasing cu+2 ions cause an increase in the corrosion rate. finally, the results indicate that the corrosion attack proceeds by linear kinetics throughout the temperature range (125215°c) studied in presence of  cl ions range (0.5-100 ppm) and cu+2 ion range (0.005-0.02 ppm). accordingly, it is evident that since the experimental results show that corrosion process follows linear rate law, it’s the chemical surface reaction which controls the kinetics in this case. the same results was found by kameswari[4] in his study of the relative corrosion resistance of different boiler steels in presence of sugar can, phosphates, sulfate, and chloride of sodium as the ash contains. he found that the weight loss data as function of temperature and time follows linear kinetics. dr. cecilia kh. haweel janet lazar 5 effect of chloride figures (6 8) show the effect of increasing the  cl ions concentration on the corrosion rate of low carbon steel pipe at different concentrations of cu+2 ions for elevated temperature. in the sodium chloride solution, the conductivity is greater hence additional anodes and cathodes can operate. it can be stated that: 1. generally the corrosion rate increases with increasing  cl ions concentration at all cu+2 concentration for all temperatures. 2. at certain temperature, corrosion rate increase with increasing  cl and cu+2 ions concentrations. the effect of  cl ions on the corrosion rate can be explained as follows: chloride ions are able to destroy passive films formed on metals such as iron, and increase the corrosion rate of attack. this behavior result from the conflicting effect of rising solution conductivity. higher solution conductivity faster or greater physical separation between the anodi and permits the formation of cathodic product fe (oh)2 at a distance from the steel surface. because fe (oh)2 formed in this way cannot provide a protective layer, the corrosion is not inhibited, so, a change in concentration of a salt can influence the corrosion rate. fig. 4 the effects of temperature on the corrosion rate of carbon steel at different copper concentration and chloride concentration of (50.25ppm) 0 100 200 300 400 500 600 700 800 100 150 200 250 temperature, (°c) c o r r o s io n r a te ,( g m d ) cu=0.005ppm cu=0.0125ppm cu=0.02ppm fig. 3 the effects of temperature on the corrosion rate of carbon steel at different copper concentration and chloride concentration of (0.5ppm) 0 100 200 300 400 500 600 700 100 150 200 250 temperature, (°c) c o rr o s io n r a te , (g m d ) cu=0.005ppm cu=0.0125ppm cu= 0.02ppm fig. 5 the effects of temperature on the corrosion rate of carbon steel at different copper concentration and chloride concentration of (100 ppm) 0 100 200 300 400 500 600 700 800 900 100 150 200 250 temperature, (°c) c o rr o s io n r a te , (g m d ) cu=0.005ppm cu=0.0125ppm cu=0.02ppm corrosion of boiler tubes in south baghdad electric station 6 effect of copper figures (9 11) show the relationship between the corrosion rate of low carbon steel and the concentration of cu+2 ppm in the solution with different  cl ion concentration at various temperature levels. it can be stated that: 1. the corrosion rate increase with increasing cu+2 ion concentration at all  cl ion concentration for all temperatures. 2. at a given temperature, corrosion rate increase with increasing cu+2 and  cl ions concentration. as the result of up normal operation i.e., the presence of high concentration of ammonia in aerated water which leads to corrode the copper alloy followed by forming oxide layers, transferred to the boiler and deposited their causing increasing the corrosion rates of carbon steel. iron dissolves by displacing another metal which is already in solution in the electrolyte. this may be noted by submerging iron in copper solution. when this is done, the iron goes into solution in the electrolyte and the copper is deposited upon the iron [5]. fig. 6 the effects of chloride ion on the corrosion rat of carbon steel at different temperature and copper concentration of (0.005ppm) 0 100 200 300 400 500 600 700 800 0 20 40 60 80 100 120 chloride concentration, (ppm) c o rr o s io n r a te , (g m d ) t=125°c t=175°c t=215°c fig. 7 the effects of chloride ion on the corrosion rate of carbon steel at different temperature and copper concentration of (0.0125ppm) 0 100 200 300 400 500 600 700 800 0 20 40 60 80 100 120 chloride concentration, (ppm) c o rr o s io n r a te , (g m d ) t=125°c t=175°c t=215°c fig. 8 the effects of chloride ion on the corrosion rate of carbon steel at different temperature and copper concentration of (0.02 ppm) 0 100 200 300 400 500 600 700 800 900 0 20 40 60 80 100 120 chloride concentration, (ppm) c o r r o s io n r a t e , ( g m d ) t=125°c t=175°c t=215°c dr. cecilia kh. haweel janet lazar 7 conclusions on the basis of the results presentedthe corrosion rate of boiler carbon steel tubes in water showed no minimum value in all experiments, (i.e. the higher the value of one variable when the second variable was fixed led to higher corrosion rate. references 1-nace basic corrosion course, houston, texas, (1970). 2-d. b. gardner, material protection, vol. 2, no. 4, p.54-61, (1962). 3-gary n. kirby, grawford & russell, inc., chemical engineering journal, vol. 86, no. 6, p.72, (1979). 4-kemeswari s., the international corrosion congress, florence, italy, april, vol. 2, p.2613, (1990). 5-powell, sheppared t., "boiler feed water purification", mcgraw-hill book company, new york fig. 11 the effects of copper ion on the corrosion rate of carbon steel at different chloride concentration and temperature (215°c) 0 100 200 300 400 500 600 700 800 900 0 0.005 0.01 0.015 0.02 0.025 copper concentration, (ppm) c o rr o s io n r a te , (g m d ) cl=0.5ppm cl=50.25ppm cl=100ppm fig. 10 the effects of copper ion on the corrosion rate of carbon steel at different chloride concentration and temperature (175°c) 0 100 200 300 400 500 600 700 0 0.005 0.01 0.015 0.02 0.025 copper concentration, (ppm) c o rr o s io n r a te , (g m d ) cl= 0.5ppm cl= 50.25ppm cl= 100ppm fig. 9 the effects of copper ion on the corrosion rate of carbon steel at different chloride concentration and temperature (125°c) 0 50 100 150 200 250 300 350 400 450 0 0.005 0.01 0.015 0.02 0.025 copper concentration, (ppm) c o r r o s io n r a te , ( g m d ) cl=0.5ppm cl=50.25ppm cl= 100ppm 8 iraqi journal of chemical and petroleum engineering vol.16 no.1 (march 2015) 2133 issn: 1997-4884 production and evaluation of liquid hydrocarbon fuel from thermal pyrolysis of virgin polyethylene plastics ammar s. abbas and fahmi abuelgasim mohamed chemical engineering department – college of engineering – university of baghdad abstract pyrolysis of virgin polyethylene plastics was studied in order to produce hydrocarbon liquid fuel. the pyrolysis process carried out for low and high-density polyethylene plastics in open system batch reactor in temperature range of 370 to 450°c. thermo-gravimetric analysis of the virgin plastics showed that the degradation ranges were between 326 and 495 °c. the results showed that the optimum temperature range of pyrolysis of polyethylene plastics that gives highest liquid yield (with specific gravity between 0.7844 and 0.7865) was 390 to 410 °c with reaction time of about 35 minutes. fourier transform infrared spectroscopy gave a quite evidence that the produced hydrocarbon liquid fuel consisted mainly alkanes and the x-ray diffraction showed no sulfur in the produced hydrocarbon liquids. key words: polyethylene, thermal, pyrolysis, kinetic study, batch reactor, plastic. introduction plastic is one of the most widely used materials in our day-to-day lives. alexander feigns it in 1862 [1]. plastic has become a needful part in our today’s world so the production of plastics has increased by an average of roughly 10% every year on a universal basis since 1950. the total global production of plastics increased from around 1.3 million tons (mt) in 1950 to 230 million tonnes in 2009, whereas the global production in 2013 reached to 299 million tonnes [2]. generally, polyethylene (pe) is one of the largest commodity plastic material in the world polyethylene has been widely investigated by enormous number of researchers because polyethylene is the main component of the total plastic content of msw. for example, polyethylene represented 55 wt.% of total plastics consumed in australia in 2003 [3]. polyethylene consists from two types: high density polyethylene (hdpe) and low density polyethylene (ldpe). hdpe has wide uses such as rigid containers such, laundry detergent bottles, milk jugs, fuel tanks for vehicles, plastic folding, chairs lumbers, folding tables, while ldpe uses include flexible films such as grocery and dry cleaning bags [4, 5]. retuning plastic to its purebred carbon cycle or monomers is not easy. also plastic is nonbiodegradable material; hence, the live cycle of plastic ends at waste plastic facilities [6]. iraqi journal of chemical and petroleum engineering university of baghdad college of engineering production and evaluation of liquid hydrocarbon fuel from thermal pyrolysis of virgin polyethylene plastics 22 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net recycling of plastics is the most attractive method. it is one of the three methods for disposal and minimization of waste plastic like incineration and landfill. landfilling needs large area for disposal of waste plastic and emissions of unacceptable gases also expensive method. incineration is a distraction method and quite expensive and may raise problems with unacceptable emissions too. so landfilling and incineration are not useful methods to solve the problem of huge piles of waste plastic. the third and most effective method of plastic recycling is pyrolysis, which is a thermal cracking reaction of the large molecular weight polymer carbon chains under oxygen free environmental and produces small molecular weight molecules [7]. pyrolysis has high capability to convert waste plastic to useful hydrocarbons. it is becoming a promising alternative in order to recover fuel oil and hydrocarbons feedstock [8, 9]. pyrolysis process can deal with small quantities of plastic containing heteroatoms (atoms other than carbon and hydrogen like oxygen, sulfur, nitrogen, chlorine and bromine) less than 2% because the presence of hero-atoms or additives lead to many problems in the process such as corrosion and difficult to control operating condition. heteroatoms are heavier than the (carbon and hydrogen). these elements increase the density of the plastic. this can be used as guide to choose the plastic for pyrolysis. the suitable plastics for pyrolysis can be known by taking flaked from waste plastic and adding it to jar of water. if more plastic floats than sinks, the waste plastic is acceptable. pyrolysis products are mainly gases, liquids, solid and coke. the liquids can either be used for further refining to produce high quality fuels or combusted for power generation. some plants have a more complete separation system by feeding the mixture of liquid and gas into distillation columns. diesel products can then be distilled out as in an oil refinery process. the non-condensable gases consist mainly from (h2, c1, c2, c3, and c4). the gases can be used as fuels to heat the pyrolysis reactor, or liquefied as fuels. if the amount is insignificant, the noncondensable gases are sent to an incinerator flaring off with the air (ash maybe contain ash) in the noncondensable gases so most commercial processes have a gas scrubber for cleaning the gases [10]. scheirs and kaminsky in 2006 [11] reported the advantage of the pyrolysis process that can deal, with all mixtures of waste plastic consisting of various sorts of plastics without sorting or treatment. while, kodera et al. in the same year [12] recommended that the product oil produced from the pyrolysis process is suitable to use in industrial boilers, power generation, and burners or in refinery with feedstock. in 1999, williams and williams [13] obtained 89.2% liquid from pyrolysis of ldpe in fluidized bed reactor at 500 °c while obtained 28.6% liquid in the same reactor at 700°c. 5 % of both of gas and liquid has been obtained from thermal pyrolysis of hdpe in semi batch reactor at 400°c during 4 hours [14]. shuber in 2007 [15] studied the thermal pyrolysis of ldpe in batch reactor closed system at 480°c during 10 minutes and obtained 73.3, 18.35, 0.34, 7.9 wt. % for liquid, gas, coke and unreacted ldpe ,respectively. while, the maximum yield of liquid, gas and coke was 23.96, 72.24 and 3.8%, respectively, during 290 to 760 minutes of reaction time of the thermal ammar s. abbas and fahmi abuelgasim mohamed -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 23 pyrolysis of waste hdpe in batch reactor closed system at temperature range 400450 °c. increasing of reaction temperature from 400 to 550°c caused, decrease in the reaction time from 760 to 54 minutes [16]. during 2013, thorat et al. [17] reported some types of plastics are suitable for pyrolysis process such as polyethylene, polypropylene and polystyrene 950 ml of oil can be recovered from 1 kg of them. the present work aimed to compare the pyrolysis behavior of hdpe and ldpe. prior to this, thermogravimetric analysis aimed to understand the pyrolysis demeanor of ldpe and hdpe. then, studying the pyrolysis behavior and reactions of two types of polyethylene (hdpe and ldpe). the best reaction conditions may be attained to produce high hydrocarbons liquid yield and good quality by changing reaction temperature and reaction time. experimental work materials virgin hdpe and ldpe pellets with average particle size of 3 mm were purchased from local markets (the source of plastic` is sabic company). the main properties of the two polymers are shown in table 1. table 1, physical and chemical properties of virgin ldpe and hdpe property ldpe hdpe density (by astm d 1505), (g/cm 3 ) 0.918 0.934 0.9560.963 melt flow index (by astm d 1238), g/10min 0.654.70 0.05– 0.43 deflection temperature at 0.46 mpa, °c 48 75-85 melting point, °c 105-115 130-135 thermal analysis thermo-gravimetric analysis (tga) was attained to study the behavior of thermal degradation for the two types of polyethylene. the tga monitors the weight loss of plastic versus the temperature; a function of temperature in a controlled nitrogen atmosphere. for each test, about 20 mg of the polyethylene pyrolysis under nitrogen flow rate approximately 35 ml/min. the heating rate was 20 °c/min from surrounding temperature to 800°c. the weight loss of polyethylene verses temperature curve was recorded to know the range of effective temperature for pyrolysis. tests were carried out using thermogravimetric analyzer tga (pc seriies tga7) located in ibn sina state company, ministry of industry and minerals. pyrolysis apparatus the apparatus used in the pyrolysis of wastes plastic consisted of batch reactor made of carbon steel of 170 mm length, 90 mm inside diameter and 110 mm outside diameter. thermo couple (type k) with digital temperature recorder (model number), connected to the top of reactor 120 mm deep was used to measure the temperature inside the reactor. the heat was supplied to the reactor by 3600 watt external electrical heaters (1600 watt heater in the bottom of the reactor and 2000 watt heater surrounding the reactor) to get the required reaction temperature. at the top end of the reactor, a tubing system was connected with two gatevalves. all tubes had 6 mm in diameter made from copper. measured amount of nitrogen enters the reactor through one of the tubes located 100 mm inside the reactor with elbow shape which has three holes to distribute the nitrogen from the bottom of reactor. production and evaluation of liquid hydrocarbon fuel from thermal pyrolysis of virgin polyethylene plastics 24 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net the condensate liquid products are collected from the bottom of the condenser (450 mm length) and the gases product leaves the system at the top of the condenser. the schematic diagram of the apparatus is shown in figure 1. fig. 1, schematic diagram of the experimental apparatus experiment procedure the batch reactor was first cleaned with naphtha. 50 g of a certain plastic particles (hdpe or ldpe) were weighted by using a four decimal balance. the reactor was closed and bolted tightly by ten nets (size 10 mm). nitrogen was supplied several times to purge the air out of the reactor (flashing the system triple for one minute each) before the experiment started. the pressure was 1 atmospheric. the two electrical heaters were turned on to attain the required reaction temperature; the accuracy of temperature readings was about 7°c and the time zero was recorded when the gases started to get out of reactor to the condenser. the cooling water was supplied by the chiller at a temperature of 3 to 5°c. the condenser was effective enough to drop the temperature of the pyrolysis product to less than 30 °c. the product separated in the condenser to non-condensable gases leaves from the top of the condenser to get out of laboratory by fan. liquid (containing wax) which was collected from the bottom of condenser in sealed cylinder. the liquid cooled to temperature 16 °c and separated by vacuum pump into liquid and wax. the liquid and the wax were weighted by the four dismal balances. the solid remaining in the reactor was defined as a coke. finally, weight of the gas was calculated by difference between initial weight of plastic and summation of other products’ weight (liquid, wax and coke). results and discussion thermo-gravimetric analysis and differential thermos-gravimetric analysis of the feedstock thermo-gravimetric analysis (tga) defined as thermal analysis technique that measures the weight loss of material as function of temperature in controlled nitrogen environmental. tga can be used to know in which range of temperature the material start and end degradation. tga curves were found to estimate the temperature range that should be used to pyrolysis ldpe and hdpe [18]. the tga curves for pyrolysis of lpde and hdpe shown in figures 2 and 3, respectively. the ldpe decomposition started at 349°c and was complete at 489°c while the hdpe decomposition started at 326°c and was complete at 495°c. the degradation temperature at which the original sample loses 50 % of its weight took place at about 457.49 and 466.71 °c for ldpe and hdpe, respectively. these results mean that the polyethylene and plastic stability is in order of hdpe and then ldpe due to their difference in molecular weight. the second dotted curve in each of figures 2 and 3, represents the differential thermal gravimetric ammar s. abbas and fahmi abuelgasim mohamed -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 25 analysis (dtga). the dtga contains only one peak, this indicates that there is only one degradation step. the peaks appear where the temperature is in the range of 457.49 to 466.71°c for ldpe and hdpe. theoretically, the peak of the dtga represents the highest pyrolysis rate for the sample, whatever the product yields. fig. 2, tga for virgin ldpe fig. 3, tga for virgin hdpe production and evaluation of liquid hydrocarbon fuel from thermal pyrolysis of virgin polyethylene plastics 26 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net the small difference in pyrolysis temperature ranges between the hpde and ldpe may be caused by the difference in the molecular weight, the chain length and the branching of the two types of plastics. thus, the order of decomposition temperature was ldpe less than hdpe. shubar [15] used tga testing to estimate the ldpe and hdpe degradation temperature. the results show the degradation temperature ranges for degradation of ldpe about 380 to 507 °c and about 386.5 to 514 °c, for hdpe, respectively. effect of temperature on the plastic pyrolysis yield the hydrocarbons (liquid and wax) are produced from thermal pyrolysis of ldpe versus time at different pyrolysis temperature as shown in figure 4. the amount of hydrocarbons increased up to 56 ml during about 11 minutes at the temperature range of 430 to 450 °c. while, at lower temperature (370°c), only 27 ml of hydrocarbons was produced through about 40 minutes of the reaction. the hydrocarbons (liquid and wax) are produce from thermal pyrolysis of hdpe versus time at different pyrolysis temperature are shown in figure 5. the amount of hydrocarbon increases with time and temperature up to 56 ml at 450°c during 7 minutes while at lower temperature, only 21 ml of hydrocarbon was produced at 370°c during 50 minutes. according to the collision theory [19, 20], which described the chemical reaction, increasing in reaction temperature, causes an increase in molecules activities, which means that more molecules have more energy to react. thus, higher temperature (430 and 450°c) gives shorter time of pyrolysis. fig. 4, the yield of hydrocarbons (liquid and wax) versus time from thermal pyrolysis of ldpe at different pyrolysis temperature 0 10 20 30 40 50 60 0 10 20 30 40 50 60 70 li q u id + w a x, m l 370 °c 390 °c 410 °c 430 °c 450 °c time (t), min ammar s. abbas and fahmi abuelgasim mohamed -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 27 fig. 5, the yield of hydrocarbons (liquid and wax) versus time from thermal pyrolysis of hdpe at different pyrolysis temperature complete time of pyrolysis the two types of polyethylene the time for completion of thermal pyrolysis reaction of ldpe and hpde was obtained experimentally to obtain the final amount of pyrolysis products. the time was started to calculate when the first produce hydrocarbon vapor reach to the condenser. the time was stopped when all the plastics were react i.e. no more than hydrocarbon vapor appear. the complete reaction time versus reaction temperatures for the ldpe and hdpe is shown in table 2. table 2, complete reaction time versus reaction temperatures for the pyrolysis of ldpe and hdpe reaction temp., °c completed ldpe pyrolysis time, min completed hdpe pyrolysis time, min 370 40 50 390 38 35 410 35 34 430 12 10 450 11 7 the pyrolysis yields of the ldpe and hdpe at completed time were summarized in figures 6 and 7 for ldpe and hdpe, respectively. as the liquid is the desired product, the maximum yield of liquid, which is about ±50 %, are produced from the pyrolysis of ldpe and hdpe in the temperatures between 390 and 410 °c (shaded area in table 2), which mean that the reaction needs about 35 minutes to complete for both types of the polyethylene. at these temperature range and reaction time, the lowest amount of wax (9 to 25 wt. %) and gases (22 to 44 wt. %) were produced. while, there was no significant amount of coke observed in pyrolysis process of ldpe while the highest coke produced from the pyrolysis of hdpe was 1.84 wt. %. at low temperatures (370, 390 and 410 °c), the liquids yield was high and reaction time was longer due to secondary cracking of the pyrolysis product occurred inside the reactor but the low liquid yield at high temperature (430 and 450 °c) during shorter time was due to the formation of less cracked high molecular weight wax. 0 10 20 30 40 50 60 0 10 20 30 40 50 60 370 °c 390 °c 410 °c 430 °c 450 °c li q u id + w a x, m l time (t), min production and evaluation of liquid hydrocarbon fuel from thermal pyrolysis of virgin polyethylene plastics 28 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net fig. 6, final products weight present of the ldpe pyrolysis fig. 7, final products weight present of the hdpe pyrolysis liquid wax gas liquid wax gas ammar s. abbas and fahmi abuelgasim mohamed -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 29 characterization of hydrocarbon liquid yield hydrocarbon liquid fuel were collected from pyrolysis of ldpe and hdpe in open system batch reactor in the temperature range of 390 to 410 °c and reaction time of about 35 minutes. fourier transform infrared analysis fourier transform infrared spectroscopy (ftir) is a significant test technique that detects different characteristic functional groups present in oil. onto interaction of infrared light with oil, chemical bonds can absorb infrared radiation in specific wavelength ranges that neglected the rest of the structure of molecules. figures 8 and 9 show the hdpe and ldpe had no different ftir spectra. ftir indicated that the structures of oils obtained from thermal pyrolysis of the two types of polyethylene are very similar. the peaks between 2960 cm -1 and 2850 cm -1 indicated the presence of ch3 (ch2)nch3 functional groups which are indicative of alkanes species as. the presences of peaks in the region of 1350 to 1500 cm -1 due to the deformation vibrations of c–h bonds confirm the presence. the structures of polyethylene and polypropylene are very similar and their thermal decompositions are probable to produce similar compositions in the derived liquid hydrocarbon [13]. the liquid obtained from thermal pyrolysis of waste hdpe [16] in batch reactor in temperature range 400 to 550 °c consist mostly of alkane and alkenes with carbon number ranges (c9 to c24). while, the (ftir) spectrometry show the oil produced from thermal pyrolysis of polyethylene in fixed bed reactors that consist from aromatic and aliphatic species such as alkanes and alkenes [21]. the reported ftir spectrometry [15] improved the liquid obtained from thermal pyrolysis of the two types of polyethylene in batch reactor at 480 °c contain similar structure of alkenes and aromatic. also contained alkanes with small difference. fig. 8, ftir for liquid produced from pyrolysis of ldpe production and evaluation of liquid hydrocarbon fuel from thermal pyrolysis of virgin polyethylene plastics 30 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net fig. 9, ftir for liquid produced from pyrolysis of hdpe simple distillation simple distillation for hydrocarbon liquid produced from pyrolysis of ldpe and hdpe was done at atmospheric pressure. the initial boiling points were 87 and 114 for the hydrocarbon liquid fuels produced from the pyrolysis of ldpe and hdpe, respectively. figure 10 shows the accumulative volume of produced hydrocarbon liquid fuels. both hydrocarbon liquids have the same fractions distribution with total light fractions (below 250 °c) of about 54 to 54.4 vol. %. liquid hydrocarbons with these fractions are rich sources for producing valuable petroleum fraction such as gasoline, kerosene, and gasoil. these results are in a good agreement with the previous work [22]. fig. 10, accumulative volume percent versus fraction range of hydrocarbon liquid fuel 7 15 22 54 46 5.2 13.4 21.4 54.4 45.6 0 10 20 30 40 50 60 up to 120 °c up to 168 °c up to 215 °c up to 250 °c rest, 250 °c+ a c c u m u la ti v e v o l. % fraction ldpe hdpe ammar s. abbas and fahmi abuelgasim mohamed -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 31 sulfur content the sulfur content of all produced liquids from thermal pyrolysis of ldpe and hdpe is zero percent. generally polyethylene plastics does not contain sulfur and water in the monomer (ethylene) which is composed of only carbon and hydrogen. the reported sulfur content of oil obtained from catalytic pyrolysis of mixture waste plastic in cylindrical reactor at temperature range of 300 to 350ºc is 0.002 wt. % [23]. other characterization properties specific gravity, kinematic viscosity, flash point, and pour point were measured for the produced hydrocarbon liquid fuel. table 3 summarizes these properties for hydrocarbon liquid fuels produced from the pyrolysis of ldpe and hdpe. table 3, characterization properties of the hydrocarbon liquid fuel property ldpe hdpe sp. gr., 0.7844 0.7865 viscosity, cst 2.85 3.49 flash point, °c 36 33 pour point, °c 15 25 the characterization properties of the produced hydrocarbon liquid are in good agreement with the reported [22, 23]. conclusion 1. tga analysis of ldpe and hdpe samples occurs in a single step and depends on their structure. the stability was found from tga to be in the order of hdpe greater than that of ldpe, due to different in molecular weight. 2. polyethylene pyrolysis products consist of a mixture of gas, oil, wax, and coke. the ratio of each product can be changed by changing the reaction condition such as temperature between 370 and 450 °c. 3. the optimum temperature range for pyrolysis of polyethylene plastics was 390 to 410 °c. 4. the reaction time for complete pyrolysis of polyethylene plastic was about 35 minutes. 5. the yield of liquid obtained was about 48.98 and 57.24 % for thermal pyrolysis of ldpe and hdpe, respectively. 6. the ftir shows no significant differences between thermal and catalytic pyrolysis of polyethylene in composition of alkanes group. 7. the sulfur content of all liquids produced from thermal and catalytic pyrolysis of ldpe and hdpe is zero percent. 8. the liquid fraction derived from thermal and catalytic pyrolysis of the two types polyethylene could be used as source of gasoline, kerosene, and gasoil. references 1. brydson, j.a. and sciencse direct. plastics materials, brent eleigh suffolk, (1999). 2. plastic – the facts, “an analysis of european plastics production, demand and waste data”, association of plastics manufacturers, (2015). 3. hackett, c. and williams r. b., "evaluation of conversion technology processes and products", journal of anal. and applied pyrolysis, 52, p.87-103, (2004). 4. kumar, s., panda, a. k., singh, r. k., “a review on tertiary recycling production and evaluation of liquid hydrocarbon fuel from thermal pyrolysis of virgin polyethylene plastics 32 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net of high-density polyethylene to fuel” resources, conservation and recycling, 55, p. 893– 910, (2011). 5. miller, s.j., shah, n. and huffman, g.p., “conversion of waste plastic to lubricating base oil’ energy and fuels, 19(4), p.1580-1586, (2005). 6. ofoma, i., "catalytic pyrolysis of polyolefin's", georgia institute of technology, department of chemical engineering, may, (2006). 7. miskolczi, n., bartha, l. and deak, gy. , ''chemical recycling of waste pe and pp'', petroleum and coal 45, p.125-130, (2003). 8. mastral, j.f., esperanza, e., berrueco, c. and ceamanos, j., "fluidized bed thermal degradation products of hdpe in an inert atmosphere and in airnitrogen mixtures" journal. anal. app. pyrolysis 70, p. 1-17, (2003). 9. demirbas, a.,"pyrolysis of municipal plastic wastes for recovery of gasoline-range hc" journal of anal. appl. pyrolysis 72, p. 97-102, (2004). 10. okuwaki, a.,” feedstock recycling of plastics in japan” polymer degradation and stability 85, p.981-988, (2004). 11. scheirs, j. and kaminsky, w., "feedstock recycling and pyrolysis of waste plastics: converting waste plastics into diesel and other fuel" edited by j. schersand, w. kaminsky, john wiley and sons, ltd. (2006). 12. kodera, y., ishihara, y. and kuroki, t., “novel process for recycling waste plastics to fuel gas using a moving-bed reactor,” energy & fuels, vol. 20, no. 4, pp. 155–158, (2006). 13. williams, p. t. and williams, e. a. “interaction of plastics in mixed plastics pyrolysis”. energy and fuels, 13, p.188–196, (1999). 14. horvat, n., ng, f.t.t., '' tertiary polymer recycling: study of pe thermolsis as a 1 st step to synthetic diesel fuel '', fuel, 78, p. 459470, (1999). 15. shubber, s. d. a., “pyrolysis of thermal plastic waste for production of fuel –like hydrocarbons”, m.sc. thesis, chemical engineering department-collage of engineering – university of baghdad-iraq, (2007). 16. kumar, s., "recovery of hydrocarbon liquid from waste high density polyethylene by thermal pyrolysis” braz. j. chem. eng. vol.28 no.4 são paulo oct. /dec, (2011). 17. thorat, p. v., warulkara, s. and sathonea, h., “pyrolysis of waste plastic to produce liquid hydroocarbons” advances in polymer science and technology: an international journal february (2013). 18. sorum, l., gronli, m.g. and hustad j.e., "pyrolysis characteristics and kinetics of municipal solid waste" fuel, 80, p.1217-1227, (2001). ammar s. abbas and fahmi abuelgasim mohamed -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 33 19. levelspiel, o., “chemical reaction engineering”, 3 th edition, john wiley and sons, 1999. 20. smith, j., m., “chemical reaction engineering”, john wiley and sons, 2014. 21. williams, p. t. , “yield and composition of gases and oils/waxes from the feedstock recycling of waste plastic,” feed. recycl. pyrolysis waste plast., pp. 285–313, (2006). 22. abbas, a. s., shubar, s. d. a., “pyrolysis of high density polyethylene for the production of fuel like liquid hydrocarbons” chemical engineering departmentcollage of engineering university of baghdad-iraq, vol. (9), p. 23-29, (2007). 23. parwar harshal, r., and lawankar shailendra, m. “waste plastic pyrolysis oil alternative fuel for ci engine – a review” res. j. engineering sci. , vol. 2(2),p. 26-30, february (2013). iraqi journal of chemical and petroleum engineering vol.17 no.4 (december 2016) 3542 issn: 1997-4884 performance study of electrodialysis for treatment fuel washing wastewater basma a. abdul majeed 1 and maitham adham zubaidy 2 1 chemical engineering department-college of engineering-university of baghdad-iraq 2 department of environment-ministry of industry and minerals-iraq abstract in this work, electrodialysis (ed) has been demonstrated to be appropriate technique for reducing the electrical conductivity of real wastewater from fuel washing unit, which has been previously treated by other electrochemical technology (electrocoagulation and electrooxidation). a five cell electrodialysis stack, with an active membrane area of 60 cm 2 per cell was employed. during a batch recirculation mode ed system, the effects of parameters such as electrical potential applied (6-18 v) and flow rate of streams (0.5-1.7 l/min.) on the performance of the total dissolved solids (tds) separation and specific power consumption (spc) were studied. the results indicate that the process of ed under potential (15 v) and flow rate (1.4 l/min) are recommended as operation conditions. the removal of tds achieved was about 95% throughout (80 min.) time of electrodialysis and (1.72 kwh/m 3 ) of spc. moreover, spc increased with an increase in the applied potential of ed stack, while it was not intensely responsive to the change in the flow rate. key words: electrodialysis, real wastewater, fuel washing, ion exchange membrane. introduction water is a critical necessity for utilization of humanity. it is crucial for rural and modern development, and also to support developing populaces that requires a harmless drinking water supply [1]. water requirements are expanding quickly and thus the accessibility of good water sources is being brought down. consequently, the reclamation and reuse of treated urban wastewaters is turning into an attractive study subject for tending to water lack. desalination is a process that removes dissolved minerals from brackish water, sea water or treated wastewater [2]. there are essentially two groups of desalination innovations utilized all through the world today. these incorporate thermal technologies and membrane technologies. thermal processes are those that evaporate water and gather condensed vapor to create distilled water. infrequently, evaporation procedures are utilized to desalinate brackish water, as it is uneconomic for this purpose. membrane technologies are much modern innovation than thermal procedures. it utilizes membranes to separate the inlet solution into two university of baghdad college of engineering iraqi journal of chemical and petroleum engineering performance study of electrodialysis for treatment fuel washing wastewater 36 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net different solutions which are called product and concentrate. reverse osmosis (ro) and electrodialysis (ed) are considered primarily membrane processes for desalination [3]. electrodialysis procedure is more cost effective than reverse osmosis for desalination of the wastewater which contains tds of 500 4000 ppm, thus, ed is generally utilized for desalination of industrial wastewater containing tds of 500 ~ 1500 ppm [4]. the reclamation and reuse of wastewater by ed was widely reported in publications like in almond industry [5], wastewater plant [6] brine from a reverse osmosis [7] and nuclear power plant [8]. ed is an electrochemical separation process in which ions are traveled through ion exchange membranes by effects of a constant current or potential. potential driving force is utilized to transfer dissolved ions from the feed water through cationic and anionic exchange membranes to form a concentrate and dilute streams [9]. an electrodialysis (ed) unit is made out of alternating anion and cation membrane sheets inserted between cathode and anode electrodes, these membrane sheets are separated from each other by spacers. ionic species are depleted from dilute cells and collected in concentrate cells. generally, several factors can affect the ed process performance such as stack design, length of the solution path in the stack, number of cells, feed concentration, flow rate and applied voltage, etc. [10, 11]. in this work, electrodialysis is proposed to be the procedure used for decreasing electrical conductivity by removing tds from a real fuel oil washing wastewater (fww) obtained from gas power station and pretreated by in situ electrocoagulationelectrooxidation method. the aims of this work are to show that ed is an appropriate method for desalting fuel washing wastewater which is previously treated by other electrochemical techniques. the effect of applied potential and feed flow rate on the tds removal efficiency has been studied to investigate the best conditions for the treatment at laboratory level. materials and method 1. ed set up the ed setup consisted of: dc power supply (uni-t, model: utp3315ft-l), three glass tank each of 2 l was used for concentrate, feed (dilute) and electrode rinse, three diaphragm pumps (type hf-9050, taiwan) equipped each with a flow meter, three pressure gauges (0-2.5 bar) to maintain the similar pressure drop across compartments. three valves were used to control solutions flow rate in the concentrate, dilute and electrodes compartments of ed cell. figure 1 shows a simplified diagram of the ed setup working in batch recirculation mode. fig. 1: the ed experimental setup http://www.iasj.net/ basma a. abdul majeed and maitham adham zubaidy -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 37 2. cell and membranes the electrodialysis cell employed at present work was homemade designed and manufactured based on the research studies in the field of lab electro-membrane processes. the ed stack packed with five pair cells of cation and anion exchange membranes. plastic spacers with 0.5 mm were placed between the membranes to form the flow paths of the dilute and concentrate streams. these spacers were designed to minimize boundary layer effects and were arranged in the stack so that all the dilute and concentrate streams were manifold separately. in this way a repeating section called a pair cell was formed; it consisted of a cation exchange membrane, a dilute flow spacer, an anion-exchange membrane, and a concentrate flow spacer. in this work, experiments were carried out by this stack equipped with six cation exchange membranes (cem) and five anion exchange membranes (aem) arranged as described in figure 2. fig. 2: the ed stack configuration membranes used in these experiments were (anion ar204sxr412) and (cation cr67, mk111) manufactured by ionics, watertown, ma, usa. table 1 shows the main characteristics of the membranes, according to the data provided by the supplier (membranes were supplied from aldora refinery, iraq). table 1: characteristics of the membranes property membrane ar204sxr412 cr67,mk111 reinforcing fabric acrylic acrylic specific weight mg/cm 2 13.7 13.7 thickness mm 0.5 0.56-0.58 burst strength kg/cm 2 7 7 capacity meq/g 2.8 2.4 chemical stability ph 1-10 1-10 the active membrane area was 60 cm 2 per cell, thus the total active area of the stack was 300 cm 2 . stainless steel (316 l) and graphite were selected as cathode and anode electrodes respectively. area of each electrode was 6 cm×10 cm with a thickness of 0.3 cm. thickness of dilution and concentrate cell were 0.15 cm with 0.6 cm 2 cross sectional area of flow for each. cathode and anode distances were 4 mm from membrane in catholyte and anolyte compartments. 3. materials sodium chloride (nacl) with purity (99.5%wt.), product of fisher chemicals (usa) was used to prepare concentrate solution at appropriate electrical conductivity. sodium sulphate (na2so4) with purity (99.5% wt.), product of fisher chemicals (usa) was used to prepare rinse 0.5 m solution. 4. analytical method in all experiments, ion conductivity meter (crison basic30, spain), was used to measure the ionic concentration, tds and conductivity of the solution during the experiments. pros kit mt 1210 avometer was used to measure current passed through the ed stack circuit. http://www.iasj.net/ performance study of electrodialysis for treatment fuel washing wastewater 38 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net 5. characterization of wastewater the source of wastewater for the ed was a real fuel oil washing wastewater (fww) obtained from the south baghdad gas power station/2 and pretreated by electrocoagulationelectrooxidation in situ method at the best investigated conditions. about 20 liters of pretreated fww were produced and collected to be post treated by desalination in ed experiments. the main characteristics of the real and pretreated fww are shown in table 2. table 2: characteristics of pretreated fww parameter real pretreated ph 6.5-7.3 6.15 turbidity (ntu) 785 24.3 tss (mg/l) 488 34 oil content (mg/l) 586 1.1 conductivity (µs/cm) 2350-2550 1722-1751 cod (mg/l) 753-760 72-79 tds (mg/l) 1370 907-923 6. experimental method in each experiment, the solutions employed were 1l of the wastewater (pretreated fww) as a dilute, 1l of nacl 895 mg/l (about 1700 µs/cm electrical conductivity) as a concentrate and 2l of na2so4 (0.5 m) as the electrolyte solution. in order to study the voltage effect on the ed process, a series of potentiostatic experiments with voltage range of (6, 9, 12, 15 and 18 v) were carried out with fixed flow rate of 0.5 l/min for dilute and concentrate solutions. in order to study the flow rate effect on the ed process, several tests at the best selected voltage were approved with a wide flow rate range (0.5, 0.8, 1.1, 1.4 and 1.7 l/min.) the tds concentration of salts as well as the conductivity of dilute and concentrate solutions were measured at 10 min. intervals, also the electrical current of the ed stack was recorded during the electrodialysis time. the time of treatment for each experiment was 60 minutes. the flow rate of the electrolyte solution was fixed at 1.2 l/min for all experiments. moreover, pressure drop was maintained the same for all solution streams in each case. in this study, the quality characteristic was the separation percentage (sp) which was calculated as follows: ( ) ( ) …(1) where, ct and ci are timed and initial ionic salts concentrations (mg/l), respectively. also, specific power consumption (spc) is an important parameter from the economical point of view, as it can be described as the energy consumed for desalting one m 3 of feed solution and it is calculated here as electrical energy consumed only in the cells (kwh/m 3 ) ∫ …(2) where e is the applied potential (volt), i is the current (ampere), vd is the dilute stream volume (m 3 ), and t is the time (hour) [12]. results and discussion 1. effect of applied voltage the treated fww by ec-eo was further reclaimed by electrodialysis (ed) process in order to recycle and reuse water in the washing fuel system. the separation performance of dissolved salts from the treated fww was investigated at constant voltage electrodialysis experimental studies through an unsteady state batch recycled run of the ed system. at time intervals of 10 min, both tds concentrations and electrical conductivity of concentrate http://www.iasj.net/ basma a. abdul majeed and maitham adham zubaidy -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 39 stream (c) and dilute stream (d) were measured. the operating time for each run was fixed at time (60 min.) while the flow rate was set at (0.5 l/min). different voltages values (6,9,12,15 and 18 v) were tested. the conductivity of concentrate and dilute streams versus time at different voltages was plotted as shown in figure 3. it can be noticed from figure 3 that the conductivity of both dilute and concentrate streams were varying with different voltages. the conductivity of dilute stream decreased faster with increasing applied voltages which means higher transfer rate and lower duration time was needed to achieve a particular target at greater potential driving force. on the other hand, the slop of conductivity curves for concentrate stream was increased with increasing the applied voltage as consequence of mass balance of the transferred salts. fig. 3: curves of conductivity of dilute (d) and concentrate (c). vs. time at different voltages and constant flow rate (0.5 l/min.) same conductivity behavior were illustrated by valero et al [5] who studied the application of electrodialysis for the treatment of almond industry wastewater. the tds removal efficiency of the dilute stream against time at different voltages was plotted in figure 4. it can be shown from figure 4 that the tds removal efficiency (sp) was increased with increase of electrical potential. at 60 min. of the process, the removal was 45.8% at 6 volte while it were 74.93% and 75.2% at 15 and 18 voltages respectively. the convergence between two last curves may be attributed to approaching close the limiting current density of the ed process [13]. fig. 4: tds removal efficiency of dilute stream against time at flow rate 0.5 l/min. and different voltages range 2. effect of flow rate from economical point view, applied voltage (15 v) was selected to examine the effect of flow rate on the separation performance. at constant voltage, various flow rates (0.5, 0.8, 1.1, 1.4 and 1.7 l/min) were tested. the conductivity of concentrate and dilute streams versus time at different flow rates was plotted in figure 5. figure 5 shows that the conductivity of dilute decreased while the conductivity of concentrate increased with the increasing flow rate. the tds removal efficiency (sp) of the dilute stream against time at different voltages was plotted in figure 6. it can be shown from figure 6 that the tds removal efficiency was increased with increasing of flow rate. after 60 min. of the process, the removal was 74.93% at flow rate (0.5 l/min) while it was achieved 90.8% and 92.5% at 1.4 and 1.7 l/min http://www.iasj.net/ performance study of electrodialysis for treatment fuel washing wastewater 40 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net respectively. increasing the flow rate leads to increasing the linear velocity of solution across the membrane surface, which results in decreasing the boundary layer thickness and improving the mass transfer coefficient. unless, in high flow rate the decrease of residence time in cells offsets the positive effect of layer thickness decrease. this behavior was reported as well by gangchoon lee [14]. fig. 5: curves of conductivity of dilute (d) and concentrate (c). vs. time at different flow rates and constant voltage (15 v) fig. 6: tds removal efficiency of dilute stream against time at applied voltage (15 v) and different flow rates range 3. specific pwer consumption for each set of potential and flow rate experiments, the specific power consumption (kwh/m 3 ) was estimated based on equation 2. the calculated spc was plotted in figure 7 for both potential and flow rate experiments. it can be seen form figure 7-a that the spc was drastically affected by the change in the applied potential force and the voltage line was extended for a wide range of spc (0.287-1.94 kw h/m 3 ). in contrast, the spc has negligible changes with flow rate chosen and the flow rate line has small range (1.39-1.69 kw h/m 3 ) in spc scale as illustrated in figure 7-b. therefore it can be concluded that voltage has the higher effect on the spc rather than the flow rate. this behavior was also observed by demircioglu et al.[15] and kabay et al.[16]. (a) (b) fig. 7: the spc for (a) different potential (at flow rate = 0.5l/min.) and (b) different flow rate (at potential =15 volte) it can be seen that the best conditions of ed process which give the higher tds removal at acceptable spc and were 15 v and 1.4 l/min. http://www.iasj.net/ basma a. abdul majeed and maitham adham zubaidy -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 41 to investigate the possibility of achieving higher removal with increasing time, an experiment was conducted at the optimum conditions a long with electrodialysis process time as shown in figure 8. the ed stack operated under potential of 15 v and the flow rate of 1.4 l/min was able to remove about 95% of tds removal and reduces the dilute solution conductivity value from 1538 µs/cm to 67 µs/cm during 80 min of operation time with about 1.72 kwh/m 3 of spc. it is clear that increasing time higher than 80 min has no effect on the removal efficiency and leading to dissipate the energy used for the system with marginal increment of removal efficiency. fig. 8: tds removal at voltage 15v , flow rate 1.4 against time conclusions a laboratory study was conducted to investigate the feasibility of electrodialysis process for treating the electrochemically pretreated fuel washing wastewater containing tds concentration about 923 ppm. removal efficiency was increased with the applied potential in the range 6-18 v due to strength of electrical potential as driving force for mass transfer. however, the increment of removal efficiency was diminished as the applied potential increases. removal efficiency in dilute was enhanced with flow rate in the range of 0.5-1.7 l/min due to the positive effect on removal rate of salts ion as a result of reducing the boundary layer thickness and improving the mass transfer coefficient. the inconsequential increment of removal rate higher than 1.4 l/min was come about because of the decline of residence time in cells. based on the operation of the electrodialysis stack used in this work, the applied voltage 15 v and the flow rate of 1.4 l/min are recommended as suitable operating conditions for wastewater solutions which corresponds to about 95% of tds removal and reduces the dilute solution conductivity around 23 times in 80 min of operation time. it was obtained that the specific power consumption (spc) was influenced by the potential applied. while it was not intensely responsive to the change in flow rate. references 1. mohtada sadrzadeh, toraj mohammadi, (2009)," treatment of sea water using electrodialysis: current efficiency evaluation", desalination, 249, 279–285. 2. mohtada sadrzadeh, toraj mohammadi, (2008)," sea water desalination using electrodialysis", desalination, 221, 440–447. 3. mourad ben sik ali, amine mnif, bechir hamrouni, mahmoud dhahbi, (2009),"desalination of brackish water using electrodialysis: effect of operational conditions", zastita materijala, 50, 141-146. 4. k sato, s. kobayashi and s. okado, (1983),"desalination and reuse of industrial waste water by electrodialesis", desalination, 47, 363—373. 5. david valero, vicente garcíagarcía, eduardo expósito, antonio aldaz, vicente montiel, (2015)," application of electrodialysis for http://www.iasj.net/ performance study of electrodialysis for treatment fuel washing wastewater 42 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net the treatment of almond industry wastewater", journal of membranescience,476,580–589. 6. lute broens , nick liebrand , harry futselaar, juan carlos de armas torrent, (2004)," effluent reuse at barranco seco (spain): a 1,000 m 3 /h case study", desalination, 167, 13-16. 7. mohammad badruzzaman, joan oppenheimer, samer adham, manish kumar, innovative beneficial reuse of reverse osmosis concentrate using bipolar membrane electrodialysis and electrochlorination processes, journal of membrane science 326 (2009) 392–399. 8. kyeong-ho yeon, jung-hoon song, joonmok shim, seung-hyeon moon, yeon-uk jeong, hyo-young joo, (2007), "integrating electrochemical processes with electrodialysis reversal and electrooxidation to minimize cod and tn at wastewater treatment facilities of power plants", desalination, 202, 400–410. 9. s. (2011), "electrodialysis technology theory and applications", desalination, trends and technologies, michael schorr ed. 10. n k ň v v lu m huč d v tv z k, (2014), "determination of limiting current density for different electrodialysis modules", chemical papers,68,324– 329. 11. zaheri, a. moheb, a. r. keshtkar, a. s. shirani, (2010), "uranium separation from wastewater by electrodialysis", iran. j. environ. health. sci. eng., 5, 7, 429-436. 12. n. kabay, m. yüksel, s. samatya, ö. arar and ü. yüksel, (2006), "effect of process parameters on separation performance of nitrate by electrodialysis", separation science and technology, 41,3201–3211. 13. farrell s., hesketh r. p. and slater c. s., (2003), "exploring the potential of electrodialysis", chemical engineering education, w u v s y • g ss nj 08028, pp 52-59. 14. gangchoon lee, (2011), "effects of operating parameters on the removal performance of electrodialysis for treating wastewater containing cadmium", desalination and water treatment, 35, 150–157. 15. m. demircioglu, n. kabay, e. ersoz, i. kurucaovah, c. safak, n. gizli, (2001), "cost comparison and efficiency modeling in the electrodialysis of brine", desalination 136, 317-323. 16. n. kabay, m. demircioglu, e. ersöz, i. kurucaovali, (2002), "removal of calcium and magnesium hardness by electrodialysis", desalination 149 343–349. http://www.iasj.net/ available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.20 no.3 (september 2019) 23 – 29 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: mohammed abdulrahman hanoon, email: mmdalsaeedy90@yahoo.com, , name: muthanna j. ahmed, email: muthannaj@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. adsorption of methyl orange from wastewater by using biochar mohammed abdulrahman hanoon and muthanna j. ahmed chemical engineering department, college of engineering, university of baghdad abstract the biochar prepared from sawdust raw material was applied in this study for the treatment of wastewater polluted with methyl orange dye. the effect of ph (2-11), initial concertation (50-250 mg/l) and time were studied. the isotherm of langmuir, frendluch and temkin models studied. the langmuir model was the best to explain the adsorption process, maximum uptake was 136.67 mg/g at 25c o of methyl orange dye. equilibrium reached after four hours of contact for most adsorbents.the values of thermodynamic parameters ∆g were negative at various temperatures, so the process spontaneous, while ∆h values were 16683 j/mol and ∆s values was 60.82 j/mol.k. keywords: anionic dye, adsorption, biochar, endothermic received on 21/01/2019, accepted on 26/02/2019, published on 30/09/1029 https://doi.org/10.31699/ijcpe.2019.3.4 1introduction water is the most important source for human life, where the human use it for drinking, washing, agriculture and other uses to support his life. water can be contaminated when the quality or composition of water is different due to the activity of humans. increasing industrial activities increase environmental pollution problems ‎[1]. there are a lot of substances that can pollution water such as inorganic acids, salts, alkali, organic matter, and dyes. wastewaters contaminated with dye represent the most amounts of the discharged industrial water. water polluted happened due to the use of large quantities of water in manufacturing processes and the first clear sign of water-polluting is color because of dyes ‎[2]. dyes are widely used by a human from antiquity and it was extracted from plants such as indigo and animals such as carmine, cochineal. humans depended on the natural sources of dyes until 1856, after that, william henry perkin trying to synthesize artificial quinine, in order to treat malaria and using allyltoluidine, has succeeded in produce aniline: a basic dye. this was the discovery of the first material synthetic dye ‎[3]. dyes are synthetic organic compounds with complex molecular structures and high molecular weights. these properties increase the difficulties of the treatment of dye wastewater. in general, the main modes of classification of dyes are based either on their chemical constitution or on their methods of application to different substrates such as textile fibers, paper, leather, plastics, etc. the different dye classes of these dyes are defined by their auxochromes, and are essentially, which is mordant dyes, direct dyes, disperse dyes, insoluble or developed azo dyes, vat dyes, reactive dyes, acidic or anionic dyes, and basic or cationic dyes. this classification allows dyers, to know the suitable dye required. it's clear that information like solubility in the dye bath, the affinity for the chosen fiber and the nature of the fixation are required for this kind of industry ‎[4]. dyes are widely used in sweets, fruit paste, green liquor, pastry both for cakes and pies as for biscuits syrup and lemonade; the cheese dairy, butter and margarine (yellow coloring) ‎[5]. releases of textile effluents, carrying dyes, into rivers, can greatly harm animals, plants, and micro-organisms living in these waters. this toxicity, therefore, could be related to the decrease of dissolved oxygen in these media. moreover, their very low biodegradability, due to their high molecular weight and their complex structures, give them a character toxic that can be high or low. as a result, they can persist for a long time in this medium, thus generating significant disturbances in the different mechanisms existing natural resources in the flora (decrease in the self-purification power of rivers, inhibition of the growth of aquatic plants and in wildlife (decimation of certain categories of fish, microorganisms) ‎[6]. the dangers of textile waste are partly short-term (obvious dangers) and secondly, in the long run. depollution techniques most commonly fall into three categories: physical processes involving precipitation methods (coagulation, flocculation, sedimentation), reverse osmosis-filtration, adsorption (on biochar ,activated carbon, zeolite….etc) and then incineration; chemical processes, with oxidation (oxygen, ozone, https://doi.org/10.31699/ijcpe.2019.3.4 m. a. hanoon and m. j. ahmed / iraqi journal of chemical and petroleum engineering 20,3 (2019) 23 29 42 oxidants such as naocl, h2o2), the complex metric methods, the use of the resin ion exchange and then the reduction (using for example na2s2o); biological processes, using aerobic treatment (with oxygen) or anaerobic treatment (without oxygen) ‎[7]. among the above mention of methods, adsorption is a process of transferring the pollutant from its source environment or fluid phase (liquid or gaseous) to the surface of the adsorbent (solid). this mode of treatment remains very limited to the elimination of different dyes. only, the cationic dyes, mordant dyes, dispersed, reactive and vat are eliminated by this technique‎[8]. adsorption occurs mainly in four stages. below are the different areas in which the molecules can be found organic or inorganic adsorption processes: diffusion of the adsorbate, from the external liquid phase, to that located in the vicinity of the surface of the adsorbent; extra granular diffusion of the material (transfer of the solute through the liquid film to the grain surface; intra-granular transfer of matter (transfer of matter into the structure porous outer surface of seeds to active sites; and adsorption reaction in contact with active sites. once adsorbed, the molecule is considered immobiled ‎[9], ‎[10]. in the last years, biochar has become very important in agriculture in terms of improving the quality of soil and productivity of agricultural crops as well as in food preservation. biochar is a granular and porous material, which is usually produced by the pyrolysis process of the raw materials at conditions that have no oxygen. the surface area and the porosity of biochar are usually high, so it is used as an absorbent to adsorb the contaminants from aqueous solutions as in the activated carbon. in this study, biochar was prepared from low cost and locally available raw material represented by sawdust. the characters surface area and total pore volume of the biochar were 58.845 m2/g and 0.061 cm3/g. therefore, the biochar has great importance in addressing and controlling the environmental pollutants ‎[11]. 2experimental work 2.1. preparation of adsorbate anionic dye used was methyl orange (sodium4-{[4 (dimethylamino) phenyl]diazenyl}benzene-1-sulfonate) purity of 99.9% with molecular weight of 327.33 g/mol, was used as adsorbate. the chemical formula of methyl orange was c14h14n3nao3s. the solutions concentration were prepared by adding a known weight of dyes to 100 ml distilled water. the methyl orang in the aqueous solution was analyzed using uv-visible spectrophotometer. the wavelength corresponding to maximum absorbance was 466 nm. 2.2. batch experiments the methyl orange uptake experiments were conducted as follows: weighting 0.02g of biochar with particle size about 200 µm and then added to the flask containing 40 ml of dye solution. the flasks were put in a shaker at speed 150 rpm at room temperature. after that, samples were filtered and the concentration of dye was calculated using uv-visible spectrophotometer. the adsorption variables study was: time (15-360 min), initial concertation (50-250 ppm) and ph (2-11). also, the adsorption isotherm models freundlich, langmuir and temkin, were used to fit data of experimental equilibrium isotherm data. the adsorption isotherms for the aqueous solution with various initial concentrations are 50,100, 150, 200, and 250 ppm for 24 hours. thermodynamic parameters were studied at different temperatures (25-45 c o ). the dye adsorption at equilibrium, qe (mg/g), was calculated as following shown in eq. (1) ‎[12]: ( ) (1) where: cₒ (mg/l) is the primary concentration of dyes. ce (mg/l) is the equilibrium concentration of dyes. v (l)is the dye solution volume. w (g) is the weight of biochar. 3results and discussion 3.1. ft-ir analysis the biochar was studied by infrared spectroscopy ftir to determine the different chemical functions present on the surface of biochar before and after the adsorption process. it is a complementary technique that focuses in general on the study of samples at a molecular level. fig. 1 shows the ftir spectra of biochar before and after adsorption of methyl orange. generally, the bands are due to different surface groups. a broad absorption band around 3,423 cm-1 is attributed to the o-h stretching vibration of hydroxyl functional including hydrogen bonding due to adsorbed water. the disappearance of the hydroxyl group is due to the adsorption of the methyl orange on the surface of the biochar. the decrease of the intensity came from the extra layer of methyl orange which increases the absorption of the infrared spectrum, leading to a decrease in the transmission intensity. (a) m. a. hanoon and m. j. ahmed / iraqi journal of chemical and petroleum engineering 20,3 (2019) 23 29 42 (b) fig. 1. ftir peaks of biochar, (a) before adsorption, (b) after adsorption 3.2. ph effect the aqueous solution ph parameter is an important factor affects the dye adsorption capacity. therefore, methyl orange dye adsorption on the biochar was tested in the ph value range (2-11). the results of the initial ph effect on the dye uptake are shown in fig. 2 figure 2 shows that the adsorption is favored by decreasing the initial ph. for initial ph values ranging from 3 to 5, sorption is accompanied increase by the initial ph decrease. on the other hand, when the initial ph varies from 6 to 11, the sorption is accompanied decrease by an increase in initial ph. this may be referring to the competition from available excess oh –ions with the dye anionic molecule for the active sites. while, acidic conditions are favorable for the adsorption between the dye and adsorbent because in case exist high electrostatic, attraction between the anionic dye and the surface charger positively of the adsorbent under acidic conditions ‎[13]. fig. 2. ph effect on the adsorption of mo (w=0.02 g/40 ml, initial concentration = 100 mg/l, t= 25˚c, speed= 150 rpm, time=240 min, biochar particle size= 200 µm) 3.3. initial concentration effect the capacity of adsorption for the biochar at various initial methyl orange concentrations is shown in fig. 3 when the initial dye concentrations increased up to 250 mg/l, it is observed that the amounts of uptake increased. this may be due to the concentration that provides an important driving force to overcome all mass transfer resistance of the dye between the aqueous and solid phase. hence a higher initial concentration of dye will enhance the adsorption process, this agrees with ‎[12], ‎[13],‎[14]. the amounts of adsorption of mo increased from 48 to 121 mg/g, when the initial dyes concentration increased from 50 to 250 mg/l. fig. 3. effect of initial concentration on the uptake of mo (w=0.02 g/40 ml, t= 25˚c, speed= 150 rpm, time=240 min, biochar particle size= 200 µm) 3.4. contact time effect the contact time effect was studied at time range of (0.15–6 h) at an initial dye concentration of 100 mg/l is explained in fig. 4. the amount of adsorbed increased rapidly in initial stage up to 2 hrs, and then gradually decreased with further process of the adsorption. finally, equilibrium achieved after 4 hrs and adsorption uptake for mo was 75 mg/g. the rapid adsorption in initial stage can be attributed to higher availability of active sites on adsorbent surface. with the passage of time, these active sites are gradually occupied by dye molecules which lead to decrease in number of active sites available for the residual dye molecules in solution. similar behavior has been reported in previous literature ‎[13], ‎[15]. m. a. hanoon and m. j. ahmed / iraqi journal of chemical and petroleum engineering 20,3 (2019) 23 29 42 fig. 4. effect of agitation time on the uptake of mo (w=0.02 g/40 ml, initial concentration = 100 mg/l, t= 25˚c, speed= 150 rpm, biochar particle size= 200 µm) 3.5. the thermodynamic parameters the change of gibbs free energy (∆g), enthalpy (∆h) and entropy (∆s) are the characteristics of thermodynamics of the adsorption system. the value of gibbs’s free energy, enthalpy, and entropy obtained from the intercept and slope of drawing data of lnkc versus 1/t as shown in fig. 5 where thermodynamic parameters calculated from eq. (2) and eq. (3).and the kc calculated from eq. (4) ‎[16]. the thermodynamic parameters tabled in table 1. the positive values of enthalpy for methyl orange indicate that the adsorption is endothermic and this value is less than 20 kj/mol which refers to phsicosorption process, while the value of entropy is positive reflects the affinity of mo for the biochar where the degree of disorder increases. the value of free energy of the thermodynamic process (∆g) at the different temperatures was negative and rise with heating, which mean spontaneous and favorable adsorption at high temperature. ( ) ( ) (2) ∆g°= -rt lnkc (3) kc = (4) where: kc: is the equilibrium constant, cad is the concentration of mo adsorbed on the adsorbent per liter of the solution (mg.l -1 ), ce: is equilibrium concentration of mo in the solution (mg.l -1 ), r: is the universal constant gas (8.314 j/mole. k), t: is the solution temperature (k) fig. 5. thermodynamic adsorption of mo on biochar. table 1. the thermodynamic parameters for the sorption of mo on biochar adsorbent t,k ∆g ,kj/mol ∆h,kj/mol ∆s, j/mol.k methyl orange 298 -1440.67 16683.7 60.82 308 -2048.86 318 -2657.1 4adsorption isotherm models the adsorptive capacity of dye by biochar was studied using the initial concentration of dyes. the experimental conditions are identical to those used previously. the results obtained were fitted to by three empirical models: langmuir, freundlich and temkin. these three models are a widely used tool for the adsorption mechanism and the quantification of the adsorbent / adsorbate affinity. these linear models are plotted in fig. 6, listed in table 2 and the results are shown in table 3. it is observed that the adsorption of methyl orange by bio char is satisfactorily described by the langmuir model with r 2 (0.9958) which is higher than the value that given by the freundlich model with r 2 (0.9778) and temkin with r 2 (0.9578). this means monolayer coverage of methyl orange molecules on biochar surface. the max absorption capacity for mo on bio char was 136.67 mg/g. the maximum adsorption uptake for langmuir model for methyl orange is compared with the other different source of adsorbates as shown in table 4. m. a. hanoon and m. j. ahmed / iraqi journal of chemical and petroleum engineering 20,3 (2019) 23 29 42 (a) (b) (c) fig. 6. isotherm of mo on biochar (a) langmuir (b) freundlich(c)temkin table 2. equations for the adsorption isotherm models model equation used reference langmuir isotherm = + [17] freundlich isotherm log qe = log kf + log ce [17] temkin isotherm qe =b ln a + b ln ce [17] table 3. parameters of isotherms model for adsorption of mo type of isotherm parameters methyl orange langmuir qm 136.67 kl 0.021 r 2 0.9958 freundlich kf 9.297 n 1.958 r 2 0.9778 temkin a 0.112 b 42.202 r 2 0.9578 table 4. the maximum adsorption capacities of mo comparison with various adsorbents adsorbent capacity of adsorption (mg/g) references acid modified carbon coated monolith 147.06 [18] activated carbon 238.1 [19] chitosan 34.83 [20] biochar 136.67 the current study modified chitosan 89.30 [21] 5conclusions the results obtained show that the biochar could be applied as a good adsorbent for methyl orange dye removal from an aqueous solution. it is observed that the adsorption of methyl orange by biochar is described by the langmuir model with r2 (0.9958) which is higher than the value that given by the freundlich model and temkin .ph is the most important variable for adsorption anionic dyes on biochar. methyl orange uptake was 138.2 mg/g at initial concertation 100 ppm. the thermodynamic parameters (δg°, δh°, and δs°) at temperature range of 298-318 k explained that the process of adsorption is endothermic. the sorption process was phsicosorption process, spontaneous and favorable adsorption at high temperature. nomenclature a: temkin constant (l/g). b: heat of adsorption (j/mol). cad: adsorbed concentration, mg/l ce: concentration at equilibrium, mg/l ci: initial concentration, mg/l δg: gibbs free energy, kj/mole δh: enthalpy change, kj/mole kc : equilibrium constant kf : freundlich's constant., mg/g kl: langmuir adsorption constant coefficient m: mass of adsorbent, g 1/n: constant indicative of the intensity of the adsorption m. a. hanoon and m. j. ahmed / iraqi journal of chemical and petroleum engineering 20,3 (2019) 23 29 42 qe: sorbed dyes molecules on the adsorbent, mg/ g qm: the maximum sorption capacity for monolayer coverage, mg/ g r: universal gas constant δs: entropy change, j/k. mole t: temperature, k v: volume, l references [1] montazer-rahmati, m.m., rabbani, p., abdolali, a. and keshtkar, a.r., 2011. kinetics and equilibrium studies on biosorption of cadmium, lead, and nickel ions from aqueous solutions by intact and chemically modified brown algae. journal of hazardous materials, 185(1), pp.401-407. [2] chong, m.n., jin, b., chow, c.w.k., saint, c., 1020 . recent developments in photocatalytic water treatment technology. a review, water research, , 44 (10), pp. 2997-3027. [3] belaid, k.d., kacha, s., kameche, m. and derriche, z., 2013. adsorption kinetics of some textile dyes onto granular activated carbon. journal of environmental chemical engineering, 1(3), pp.496503. [4] eren, z., acar, f.n., 2006. adsorption of reactive black 5 from an aqueous solution: equilibrium and kinetic studies, desalination, 194 (1-3), 1-10. [5] t. robinson, b. chandran and p. nigam., 2002. removal of dyes from a synthetic textile dye effluent by biosorption on apple pomace and wheat straw. bioresource technology 85., pp,43–49. [6] gupta, v.k., 2009. application of low-cost adsorbents for dye removal–a review. journal of environmental management, 90(8), pp.2313-2342. [7] p. janos, h. buchtova and m. ryznarova.,2003. sorption of dyes from aqueous solutions onto fly ash. water res., 37., pp, 4938–4944. [8] gautam, r.k., mudhoo, a. and chattopadhyaya, m.c., 2013. kinetic, equilibrium, thermodynamic studies and spectroscopic analysis of alizarin red s removal by mustard husk. journal of environmental chemical engineering, 1(4), pp.1283-1291. [9] hameed, b.h., din, a.m. and ahmad, a.l., 2007. adsorption of methylene blue onto bamboo-based activated carbon: kinetics and equilibrium studies. journal of hazardous materials, 141(3), pp.819-825. [10] chen, h., zhao, j., dai, g., 2011. silkworm exuviae. a new non-conventional and low-cost adsorbent for removal of methylene blue from aqueous solutions. journal of hazardous materials 186, 1320-1327. [11] bouras,h.d.,yeddou,a.r.,bouras,n.,hellel,d., 2017. biosorption of congo red dye by aspergillus carbonarius m333 and penicillium glabrum pg1: kinetics, equilibrium and thermodynamic studies. journal of the taiwan institute of chemical engineers 80, 915-923. [12] varlikli, c., bekiarib, v., kus, m., boduroglu, n., oner, i., lianos, p., lyberatos, g.,icli, s. (2009). adsorption of dyes on sahara desert sand. journal of hazardous materials 170, 27–34. [13] taha, dakhil & samaka, israa. (2012). natural iraqi palygorskite clay as low cost adsorbent for the treatment of dye containing industrial wastewater. journal of oleo science. 61. 729-36. 10.5650/jos.61.729. [14] raghad f.almilly.,mohanned h.hasan,2017 ’waste water treatment by liquid-solid adsorption using calcined sand-clay mixture adsorbent’ iraqi journal of chemical and petroleum engineering.vol.18.no.2. 67-81. [15] jenan a.al-najar.,2017”removal of dyes from synthetic wastewater by agricultural waste’ iraqi journal of chemical and petroleum engineering.vol.18.no.3.31-48 [16] basma a. abdelmajeed., raheem j.muhseen., nawras j.jassim.,2018’adsorption of diclofenac sodium and ibuprofen by bentonite polyureaformaldehyde thermodynamics and kinetics study’ iraqi journal of chemical and petroleum engineering.vol.19.no.1.29-43. https://www.sciencedirect.com/science/article/pii/s0304389410012082 https://www.sciencedirect.com/science/article/pii/s0304389410012082 https://www.sciencedirect.com/science/article/pii/s0304389410012082 https://www.sciencedirect.com/science/article/pii/s0304389410012082 https://www.sciencedirect.com/science/article/pii/s0304389410012082 https://www.sciencedirect.com/science/article/pii/s0304389410012082 https://www.sciencedirect.com/science/article/abs/pii/s0043135410001739 https://www.sciencedirect.com/science/article/abs/pii/s0043135410001739 https://www.sciencedirect.com/science/article/abs/pii/s0043135410001739 https://www.sciencedirect.com/science/article/abs/pii/s0043135410001739 https://www.sciencedirect.com/science/article/pii/s221334371300047x https://www.sciencedirect.com/science/article/pii/s221334371300047x https://www.sciencedirect.com/science/article/pii/s221334371300047x https://www.sciencedirect.com/science/article/pii/s221334371300047x https://www.sciencedirect.com/science/article/pii/s221334371300047x https://www.sciencedirect.com/science/article/abs/pii/s0011916406003559 https://www.sciencedirect.com/science/article/abs/pii/s0011916406003559 https://www.sciencedirect.com/science/article/abs/pii/s0011916406003559 https://www.sciencedirect.com/science/article/abs/pii/s0043135401005218 https://www.sciencedirect.com/science/article/abs/pii/s0043135401005218 https://www.sciencedirect.com/science/article/abs/pii/s0043135401005218 https://www.sciencedirect.com/science/article/abs/pii/s0043135401005218 https://www.sciencedirect.com/science/article/pii/s0301479708003290 https://www.sciencedirect.com/science/article/pii/s0301479708003290 https://www.sciencedirect.com/science/article/pii/s0301479708003290 https://www.sciencedirect.com/science/article/abs/pii/s004313540300469x https://www.sciencedirect.com/science/article/abs/pii/s004313540300469x https://www.sciencedirect.com/science/article/abs/pii/s004313540300469x https://www.sciencedirect.com/science/article/pii/s2213343713001863 https://www.sciencedirect.com/science/article/pii/s2213343713001863 https://www.sciencedirect.com/science/article/pii/s2213343713001863 https://www.sciencedirect.com/science/article/pii/s2213343713001863 https://www.sciencedirect.com/science/article/pii/s2213343713001863 https://www.sciencedirect.com/science/article/pii/s0304389406008739 https://www.sciencedirect.com/science/article/pii/s0304389406008739 https://www.sciencedirect.com/science/article/pii/s0304389406008739 https://www.sciencedirect.com/science/article/pii/s0304389406008739 https://www.sciencedirect.com/science/article/pii/s0304389410015840 https://www.sciencedirect.com/science/article/pii/s0304389410015840 https://www.sciencedirect.com/science/article/pii/s0304389410015840 https://www.sciencedirect.com/science/article/pii/s0304389410015840 https://www.sciencedirect.com/science/article/pii/s0304389410015840 https://www.sciencedirect.com/science/article/pii/s1876107017304054 https://www.sciencedirect.com/science/article/pii/s1876107017304054 https://www.sciencedirect.com/science/article/pii/s1876107017304054 https://www.sciencedirect.com/science/article/pii/s1876107017304054 https://www.sciencedirect.com/science/article/pii/s1876107017304054 https://www.sciencedirect.com/science/article/pii/s1876107017304054 https://www.sciencedirect.com/science/article/pii/s0304389409007365 https://www.sciencedirect.com/science/article/pii/s0304389409007365 https://www.sciencedirect.com/science/article/pii/s0304389409007365 https://www.sciencedirect.com/science/article/pii/s0304389409007365 https://www.jstage.jst.go.jp/article/jos/61/12/61_729/_article/-char/ja/ https://www.jstage.jst.go.jp/article/jos/61/12/61_729/_article/-char/ja/ https://www.jstage.jst.go.jp/article/jos/61/12/61_729/_article/-char/ja/ https://www.jstage.jst.go.jp/article/jos/61/12/61_729/_article/-char/ja/ https://www.jstage.jst.go.jp/article/jos/61/12/61_729/_article/-char/ja/ http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/204 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/204 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/204 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/204 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/204 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/64 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/64 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/64 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/64 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/223 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/223 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/223 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/223 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/223 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/223 m. a. hanoon and m. j. ahmed / iraqi journal of chemical and petroleum engineering 20,3 (2019) 23 29 42 الفحم الحيويمن المحلول المائي باستخدام البرتقاليامتزاز صبغه المثيل محمد عبد الرحمن حنون و مثنى جبار احمد قسم الهندسة الكيمياوية ، كمية الهندسة ، جامعة بغداد الخالصة في هذه الدراسة لمعالجة المياه المموثة بصبغة المثيل تم استخدام الفحم النباتي المحضر من نشارة الخشب ممغم / لتر( والوقت. 200-00التركيز األولي ) ( وتأثير11-2البرتقالي. تمت دراسة تأثير األس الهيدروجيني ) كما تم دراسة موديالت االيزوثيرم النكماير وفرندليش وتيمكن. لوحظ ان افضل موديل ينطبق لشرح عممية درجة مئوية لصبغة 20ممغم / جم عند 133.31هو النكماير . وكان الحد األقصى لالمتصاص االمتزاز . كانت قيم الديناميكا المثيل البرتقالي. تم الوصول إلى التوازن بعد أربع ساعات من اجراء عممية االمتزاز / h∆ 16683 jن كانت قيم سالبة في درجات حرارة مختمفة ، لذلك كانت العممية تمقائية ، في حي gالحرارية mol وكانت قيمs∆ 60.82 j / mol.k. ماص للحرارة ، االصباغ ، االسترجاع ، االمتساز: الكلماث الدالت iraqi journal of chemical and petroleum engineering vol.17 no.3 (september 2016) 101108 issn: 1997-4884 removal of cadmium ions from wastewater by batch experiments eman abed m., lahieb faisal m. and younis swadi t. environmental engineering department–college of engineering ـــuniversity of almustansiriyah abstract adsorption experiments were carried out using two different low-cost sorbent materials, date seeds and olive seeds. these sorbents used as a single phase (not as mixture) to remove cadmium ions from simulated wastewater by adsorption process. the equilibrium time was found at 2 hr. the experiments include different parameters such sorbent type and weight and contact time. it was found that both of olive seed and date seed have approximately the same adsorption capacity (qm) with 15.644 mg/g and 15.2112 mg/g, respectively. equilibrium isotherms and kinetic studies have been carried out. langmuir isotherm model better fits the experimental data compared with the freundlich isotherm for olive seed, while freundlich isotherm fits for date seed .a pseudo-second order kinetic model was appropriate to the experimental data for both seeds. it can be concluded that the olive seed and date seed could be a good sorbent for the removal of cadmium ions from wastewater. keywords: cadmium ions, date and olive seeds, wastewater. introduction toxic metal compounds not only contaminate surface water sources (seas, lakes, ponds, and reservoirs), but also contaminate underground water in trace amounts by leaching from the soil after rain and snow [1]. cadmium takes much attention by environmentalists as one of the most toxic heavy metals. the increasing presence of cadmium in the environment is chiefly due to its use in electroplating, smelting, plastics, pigments, ceramics, battery, and cadmium-rich phosphate fertilizers and mining [2, 3]. cadmium has negative effects on the environment and is easily accumulated in living systems. the harmful effects of cadmium ions are renal damage, hypertension, proteinuria, kidney stone formation and testicular atrophy [4]. it combines with sulfa hydria group in protein and restrains the activity of enzyme [5]. a lot of methods are investigated to treat the metal contaminated effluent; these methods are either inefficient or expensive especially when the concentration of the containments is low. for this reasons the use of agricultural wastes in removal of heavy metals has been investigated. agricultural wastes are characterized by ready availability, affordability, eco-friendliness, and high uptake capacity for heavy metals due to the presence of functional groups which can bind metals to increase the university of baghdad college of engineering iraqi journal of chemical and petroleum engineering removal of cadmium ions from wastewater by batch experiments www.iasj.netavailable online at: 6) 201 september( 3no. 7ijcpe vol.1 201 removal of heavy metal from effluents [6]. several low-cost materials such as peanut husk charcoal and fly ash [7], scoria [8], moringa oleifera bark [9], orange peel [10], watermelon shell [11], sunflower leaves [12], eichhnornia crassipes [13], soybean meal waste [14], punica granatum peel waste [15], acacia leucocephala bark [16], wheat straw [17] and maize cob [18] have been used to remove metal ions from aqueous solutions. date seed is usually discarded as unwanted material in many date producing countries such as iraq. date is cultivated in arid and semi-arid regions and can thrive in long and hot summers, low rainfall and very low relative humidity [19]. iraq is one of the largest producers of date fruits; while suitable environment for the cultivation of olives is in the areas near the foothills of the mountains and olive trees grow in many types of land. this seed represents a big size of the total weight of fruit (both materials are abundantly available through our country and the world) [20]. adsorption is the most suitable method used to remove metals ions from the aqueous solutions. adsorption is a surface phenomenon, in which molecules of adsorbate are attracted and held to the surface of an adsorbent until equilibrium is reached between adsorbed molecules and those still freely distributed in the carrying gas or liquid. the adsorption phenomenon depends on the interaction between the surface of the adsorbent and the adsorbed species. the interaction may be due to: (1) chemical bonding; (2) hydrogen bonding; (3) hydrophobic and (4) van der waals forces [21]. the adsorption isotherms describe the relationship between the amount adsorbed by a unit weight of solid adsorbent and the amount of solute remaining in the solution at equilibrium. langmuir and freundlich isotherms models are used frequently to describe adsorption of metal ions by different materials. the aim of this work is to explore the possibility of utilizing seeds of date and olive for the adsorptive removal of cadmium (ii) from simulated wastewater. different experimental parameters have been investigated such as sorbents concentration, contact time, and initial cadmium (ii) concentration. adsorption isotherms and kinetics were investigated and different adsorbent models were used to fit the experimental data and to elucidate the possible adsorption mechanism. materials and methods 1. adsorbate and adsorbent cadmium solutions of requirable concentration (20, 30, 40, and 50 mg/l) have been prepared by dissolving the appropriate amount of cadmium nitrate cd (no3)2·4h2o in distilled water. the date seeds and olive seeds were prepared for the present study by grinding and sieving to obtain a grain size of range less than 105µm in diameter and then washed with distilled water and dried in an oven at 105 o c for 24 hr and stored in a desiccator until use (during the research period approximately 60 days). 2. batch adsorption experiments batch experiments are performed with 100 ml of a sample solution and a requirable adsorbent dose of 0.15, 0.25, 0.35 and 0.45 gm and parameter such as contact time, concentration of solution. the mixture is transferred into a 250 ml conical flask and stirred for 3 hour, filtered and analyzed for its absorbed concentration. all experiments are conducted at room temperature conditions. absorbed http://www.iasj.net/ eman abed m., lahieb faisal m. and younis swadi t. 201 )6201september ( 3no. 17ijcpe vol. www.iasj.netonline at: available concentrations are determined by atomic absorption spectrophotometer. 3. fourier-transform-infrared analysis (ftir) it is essential to identify the functional groups present on the biomass involved in this search. the main effective binding sites can be identified by ftir spectral comparison of the biosorbent, cadmium ions loaded biosorbent. biosorbent were examined using (shimadzo ftir, 800 series spectraphotometer). two flasks of 250 ml were filled with 100 ml of each metal solution 50 mg/l and 1gm of both dried seeds (olive and date). the flasks were then placed on a shaker and agitated continuously for 3hr at 200 rpm. samples of each flask were dried in oven at 50 c 0 for 48 hr. results and discussion 1. ftir analysis figure 1 (a and b) show the ftir spectra of date seeds and olive seeds, respectively. numerous chemical functional groups have been characterized as potential adsorption sites to be responsible for binding cadmium onto date and olive seeds. the spectrum pattern of loaded cd (ii) showed changes in the peak absorption as compared to unloaded cd (ii) which result from adsorption process. contribution of each functional group in this process is summarized in tables 1 and 2. table 1: functional groups responsible for cadmium adsorption by date seed wave number (cm -1 ) assignment groups after adsorption of cd (ii) 3387.00 carboxylic acid, amides 3402.43 2908.65 carboxylic acid 2916.37 1373.03 nitro groups 1373.32 1157.29 carboxylic acid 1161.15 1111.00 carboxylic acid 1111.14 817.82 aromatic 825.53 659.66 alkyl halides 667.37 table 2: functional groups responsible for cadmium adsorption by olive seed wave number (cm -1 ) assignment groups after adsorption of cd (ii) 3398.57 carboxylic acid, amides 3410.15 1639.49 carboxylic, hydroxyle, alkanes 1654.92 1423.47 carboxylic acid 1427.32 1327.03 nitro groups 1334.74 1161.15 carboxylic acid 1165.00 1122.57 carboxylic acid 1188.71 1041.56 carboxylic acid 1045.42 813.96 aromatic 833.25 601.79 alkyl halides 605.65 fig. 1: ftir spectrums a. date seed raw, loaded cd (ii); b. olive seed raw, loaded cd (ii) 2. effect of sorbent type and amount figure 2 shows the effect of sorbent types (date seeds and olive seeds) on the removal percentage (r %) of cd in simulated wastewater. the obtained data indicated that both of biosorbent showed high removal efficiency towards cd (ii) ions about 98.12% and http://www.iasj.net/ removal of cadmium ions from wastewater by batch experiments www.iasj.netavailable online at: 6) 201 september( 3no. 7ijcpe vol.1 201 96% removal efficiency for date and olive, respectively. difference in sorption capability of heavy metals by sorbent materials is due to the different affinity of metal ions to active groups on the substrate [22]. fig. 2: type of adsorbent on removal efficiency 3. effect of contact time the effect of contact time was tested at initial metal ions concentration of 40 ppm/100 ml and ph 5.5 shown in figure 3. there was a rapid adsorption of cd (ii) in the first 60 min, and, thereafter, the rate of adsorption become slower; this is due to a decrease or lack of number of active sites [23]. it can be concluded that 2 h. contact time is sufficient to reach equilibrium conditions for cadmium ions. the maximum removal efficiency of cd (ii) was (98.2% by date sorbent and 96.15% by olive sorbent, respectively). fig. 3: effect of contact time on removal efficiency 4. effect of cadmium initial concentration the adsorption experiments were tested at initial concentrations of 20, 30, 40, and 50 mg/l with a constant date and olive amounts of 0.25 g, contact time 60 min and ph 5.5. figure 4 shows the results. the plot show that increase in the cd (ii) concentration from 20-50 mg/l results in a decrease in percentage cd (ii) removal from 99% to 97.31% for date sorbent, and 97.68% to 94.88% for olive sorbent, respectively. the decrease in the removal efficiency of cd (ii) can be attributed to the saturation of available active sites on the both seeds (date and olive). the increase in adsorption capacity may be due to the higher adsorption rate and the utilization of all available active sites for adsorption at higher cd (ii) concentration [24]. fig. 4: effect of initial concentration of cadmium on removal efficiency adsorption isotherm models two isotherm models were used to describe how solutes interacted with the sorbents. the langmuir sorption model is based on the assumption that maximum sorption corresponds to a saturated monolayer of solute on the sorbent surface. this model also supposes that all the sorption sites are assumed to be identical, each site retains one molecule of the given compound and all sites are energetically independent of the sorbed http://www.iasj.net/ eman abed m., lahieb faisal m. and younis swadi t. 201 )6201september ( 3no. 17ijcpe vol. www.iasj.netonline at: available quantity [24]. the linear form of the langmuir eq. can be described by: …(1) where ce (mg l −1 ) is the equilibrium concentration of the sorbate, qe (mg g −1 ) is the amount of sorbate per unit mass of sorbent, qm (mg g −1 ) and b (lmg −1 ) are langmuir constants related to sorption capacity and rate of sorption, respectively. the linear plot of specific sorption (ce/qe) against the equilibrium concentration (ce) shown in figure 5a. the freundlich isotherm is the earliest known relationship describing the sorption equation. the fairly satisfactory empirical isotherm can be used for non-ideal sorption that involves heterogeneous surface energy systems [24]. the linear form of the freundlich model is expressed by the following eq.: …(2) where kf (mg 1− (1/n) l 1/n g −1 ) is roughly an indicator of the sorption capacity and n is the sorption intensity. the equilibrium data were further analyzed using the linear form of freundlich isotherm, by plotting ln qe versus ln ce figure 5b the calculated langmuir and freundlich isotherms constants and the corresponding coefficients of determination are shown in table 3. fig. 5a: applying langmuir adsorption isotherm fig. 5b: applying freundlich adsorption isotherm table 3: langmuir and freundlich isotherms constants and the corresponding coefficients adsorbent type isotherm models langmuir freundlich r² a b r² n k date seed 0.682 4.2194 0.3692 0.854 0.217 0.21281 olive seed 0.806 38.462 0.491 0.712 1.9531 333.423 it can be observed that experimental data fit the isotherm adequately. the applicability of the freundlich model to the experimental data indicates monolayer coverage on heterogeneous adsorbent surface by each of cd (ii) ion for date seed; while for olive seed langmuir model is the best model which describes their experimental data. adsorption kinetics adsorption kinetics can be described by various kinetics models; pseudo-first-order, pseudo-second order. the linear form of the pseudofirst order rate model is represented in eq. 3. the pseudo-second-order rate model can be represented by eq. 4 [25]: ( ) …(3) http://www.iasj.net/ removal of cadmium ions from wastewater by batch experiments www.iasj.netavailable online at: 6) 201 september( 3no. 7ijcpe vol.1 201 …(4) where qe is the amount of metal sorbed at equilibrium (mg/g); qt is the amount of metal sorbed at time t (mg/g); and k1, k is the equilibrium rate constant of pseudo first order and pseudo second order sorption, respectively. figure 6 shows the both kinetics models which were used in this study; constants (k1, k) and other parameters of both models, compiled in table 4 along with correlation coefficients (r 2 ) values. table 4: various kinetics models parameters fig. 6a: applying pseudo-first-order for adsorption of cd +2 using date seed and olive seed fig. 6b: applying pseudo secondorder for adsorption of cd +2 using date seed and olive seed the results indicate that, the adsorption process of cd (ii) at the surface of the both adsorbents (date and olive seeds) followed the second order reaction kinetics. conclusions the removal of cd (ii) in synthetic water by using adsorption technology was studied in the batch experimental systems. based on the results, the following conclusions can be drawn. the prepared sorbent is an efficient biomaterial for removal of cadmium ion from industrial wastewater. equilibrium metal adsorption decreased with the increase in the initial concentration of cd (ii) ions suggesting the applicability of the biomaterial at lower concentrations. the sorption of cd (ii) by date seed is a monolayer according to freundlich adsorption isotherm, while by using olive seed as adsorbent the fit model is langmuir. the percent removal of cd (ii) by adsorption under the conditions employed in this study is 95.1%, 97.8% by date and olive, respectively, with an effective dose of 0.25 g of bioadsorbent. adsorption equilibrium for the metal was reached in about 2 h. the study demonstrated that the adsorption process was coincided second order kinetics. this methodology can be applied to the removal of toxic metals from wastewater efficiently. the method type of adsorbent qe experimental mg/g pseudo-first-order pseudo-second-order k1 1/min qe calculated mg/g r 2 k2 g/mg.min qe calculated mg/g r 2 date seed 15.2112 0.027 4.665 0.845 0.0045 16.667 0.973 olive seed 15.644 0.022 4.047 0.810 0.0081 16.393 0.995 http://www.iasj.net/ eman abed m., lahieb faisal m. and younis swadi t. 201 )6201september ( 3no. 17ijcpe vol. www.iasj.netonline at: available was simple, cost effective and environmental friendly. references 1. r. r. bansode, (2002), "treatment of organic and inorganic pollutants in municipal wastewater by agricultural by-product based granular activated carbons", [m.s. thesis], the department of food science, louisiana state university and agricultural and mechanical college, baton rouge, la, usa. 2. b. volesky, (1990), "biosorption of heavy metals", crc press, boca raton, fl. 3. j.wase, c.f. forster, (1997), "biosorbents for metal ions", taylor & francis, london. 4. i. kula, m. ugurlu, h. karaoglu, a. c， elik, (2008), "adsorption of cd(ii) ions from aqueous solutions using activated carbon prepared from olive stone by zncl2 activation", bioresour. technol. vol. 99, pp. 492–501. 5. g. chen, g. zeng, l. tang, c. du, x. jiang, g. huang, h. liu, g. shen, (2008), "cadmium removal from simulated wastewater to biomass byproduct of lentinus edodes", bioresour. technol. vol. 99, pp.7034–7040. 6. k. o. olayinka, b. i. alo, and t. adu, (2007), "sorption of heavy metals from electroplating effluents by low-cost adsorbents ii: use of waste tea, coconut shell and coconut husk", journal of applied sciences, vol. 7, no. 16, pp. 2307–2313. 7. abdel salam, o.e., reiad, n.a. and elshafei, m.m. (2011), "a study of the removal characteristics of heavy metals from wastewater by low-cost adsorbents", journal of advanced research, vol. 2, pp. 297-303. http://dx.doi.org/10.1016/j.jare.2011 .01.008. 8. kwon, j.s., yun, s.t., lee, j.h., kim, s.o. and jo, h.y. (2010), "removal of divalent heavy metals (cd, cu, pb, and zn) and arsenic (iii) from aqueous solutions using scoria: kinetics and equilibria of sorption", journal of hazardous materials, vol. 174, pp. 307-313. http://dx.doi.org/10.1016/j.jhazmat. 2009.09.052 9. reddy, d.h.k., seshaiah, k., reddy, a.v.r., rao, m.m. and wang, m.c. (2010), "biosorption of pb2+ from aqueous solutions by moringa oleifera bark: equilibrium and kinetic studies", journal of hazardous materials, vol. 174, pp. 831-838. http://dx.doi.org/10.1016/j.jhazmat. 2009.09.128 10. liang, s., guo, x. and tian, q., (2011), "adsorption of pb 2+ and zn 2+ from aqueous solutions by sulfured orange peel", desalination, vol. 275, pp.212-216. http://dx.doi.org/10.1016/j.desal.201 1.03.001 11. banerjee, k., ramesh, s.t., gandhimathi, r., nidheesh, p.v. and bharathi, k.s., (2012),"a novel agricultural waste adsorbent, watermelon shell for the removal of copper from aqueous solutions", iranica journal of energy and environment, vol. 3, pp.143-156. 12. benaїssa, h. and elouchdi, m.a., (2007), "removal of copper ions from aqueous solutions by dried sunflower leaves", chemical engineering and processing, vol. 46, pp. 614-622. http://dx.doi.org/10.1016/j.cep.2006 .08.006 13. li, x., liu, s., na, z., lu, d. and liu, z., (2013), "adsorption concentration and recovery of aqueous heavy metal ions with the root powder of eichhornia crassipes", ecological engineering, http://www.iasj.net/ http://dx.doi.org/10.1016/j.jare.2011.01.008 http://dx.doi.org/10.1016/j.jare.2011.01.008 http://dx.doi.org/10.1016/j.jhazmat.2009.09.052 http://dx.doi.org/10.1016/j.jhazmat.2009.09.052 http://dx.doi.org/10.1016/j.jhazmat.2009.09.128 http://dx.doi.org/10.1016/j.jhazmat.2009.09.128 http://dx.doi.org/10.1016/j.cep.2006.08.006 http://dx.doi.org/10.1016/j.cep.2006.08.006 removal of cadmium ions from wastewater by batch experiments www.iasj.netavailable online at: 6) 201 september( 3no. 7ijcpe vol.1 201 vol. 60, pp. 160-166. http://dx.doi.org/10.1016/j.ecoleng. 2013.07.039. 14. witek-krowiak, a. and reddy, d.h.k., (2013), "removal of microelemental cr(iii) and cu(ii) by using soybean meal waste unusual isotherms and insights of binding mechanism", bioresource technology, vol. 127, pp. 350-357. http://dx.doi.org/10.1016/j.biortech. 2012.09.072. 15. bhatnagar, a. and minocha, a.k., (2010), "biosorption optimization of nickel removal from water using punica granatum peel waste", colloids and surfaces b: biointerfaces, vol. 76, pp. 544548. http://dx.doi.org/10.1016/j.colsurfb. 2009.12.016. 16. munagapati, v.s., yarramuthi, v., nadavala, s.k., alla, s.r. and abburi, k., (2010), "biosorption of cu(ii), cd(ii) and pb(ii) by acacia leucocephala bark powder: kinetics, equilibrium and thermodynamics", chemical engineering journal, vol. 157, pp. 357-365. http://dx.doi.org/10.1016/j.cej.2009. 11.015. 17. doan, h.d., lohi, a., dang, v.b.h. and dang-vu, t., (2008), "removal of zn+ 2 and ni+ 2 by adsorption in a fixed bed of wheat straw", process safety and environmental protection, vol. 86, pp. 259267.http://dx.doi.org/10.1016/j.psep .2008.04.004. 18. abdel-ghani, n.t., hefny, m. and el-chaghaby, g.a.f., (2007), "removal of lead from aqueous solution using low cost abundantly available adsorbents", international journal of environmental science and technology, vol. 4, pp. 67-73. http://dx.doi.org/10.1007/bf033259 63. 19. ahmad, t., danish, m., rafatullah, m., ghazali, a., sulaiman, o., hashim, r., & ibrahim,m. n. m., (2012), "the use of date palm as a potential adsorbent for wastewater treatment: a review", environ sci pollut res int, vol. 19, no.5, pp. 1464-1484. doi:10.1007/s11356-011-0709-8. 20. afiq, m. j. a., rahman, r. a., man, y. b. c., al-kahtani, h. a., & mansor, t. s. t., (2013), "date seed and date seed oil", international food research journal, vol.20, no.5, pp. 2035. 21. r. c. ansal and m. goyal, (2005), "activated carbon adsorption", taylor & francis, london, uk. 22. osman h.e., badwy r.k., ahmed h.f., (2010), "usage of some agricultural byproducts in the removal of some heavy metals from industrial wastewater", journal of phytology, vol. 2, no.3, pp.51-62. 23. n. kannan and a. xavier, (2001),"new composite mixed adsorbents for the removal of acetic acid by adsorption from aqueous solutions a comparative study", toxicological and environmental chemistry, vol. 79, no. 1-2, pp. 95– 107. 24. kumar p.s., ramalingam s.,and sivanesan s., (2012),"removal of cadmium (ii) from aqueous solution by agricultural waste cashew nut shell", korean j. chem. eng., vol. 29, no.6, pp.756-768. 25. raj, g., (2001),"chemical kinetics in advanced physical chemistry", 4th ed., geol publishing house: meerut, india; pp. 669-676 and 149-150. http://www.iasj.net/ http://dx.doi.org/10.1016/j.ecoleng.2013.07.039 http://dx.doi.org/10.1016/j.ecoleng.2013.07.039 http://dx.doi.org/10.1016/j.biortech.2012.09.072 http://dx.doi.org/10.1016/j.biortech.2012.09.072 http://dx.doi.org/10.1016/j.colsurfb.2009.12.016 http://dx.doi.org/10.1016/j.colsurfb.2009.12.016 http://dx.doi.org/10.1016/j.cej.2009.11.015 http://dx.doi.org/10.1016/j.cej.2009.11.015 http://dx.doi.org/10.1016/j.psep.2008.04.004 http://dx.doi.org/10.1016/j.psep.2008.04.004 http://dx.doi.org/10.1007/bf03325963 http://dx.doi.org/10.1007/bf03325963 iraqi journal of chemical and petroleum engineering vol.15 no.3 (september 2014) 51-60 issn: 1997-4884 analytical model for detection the tilt in originally oil water contacts jalal abdulwahid al-sudani petroleum engineering department-college of engineeringuniversity of baghdad abstract many carbonate reservoirs in the world show a tilted in originally oil-water contact (oowc) which requires a special consideration in the selection of the capillary pressure curves and an understanding of reservoir fluids distribution while initializing the reservoir simulation models. an analytical model for predicting the capillary pressure across the interface that separates two immiscible fluids was derived from reservoir pressure transient analysis. the model reflected the entire interaction between the reservoir-aquifer fluids and rock properties measured under downhole reservoir conditions. this model retained the natural coupling of oil reservoirs with the aquifer zone and treated them as an explicit-region composite system; thus the exact solutions of diffusivity equation could be used explicitly for each region. the reservoir-aquifer zones were linked by a capillary transition zone that reflected the pressure difference across the free water level. the principle of superposition theorem was applied to perform this link across the free water level to estimate the reflected aquifer pressure drop behavior that holds the fluid contacts in their equilibrium positions. the results of originally oil water contact positions generated by the proposed model were compared with data obtained from a carbonate oil field; the results given by the model showed full agreement with the actual field data. keywords: capillary pressure, tilted oil water contact introduction many carbonate reservoirs in the world show a tilted in oowc; an inaccurate determination for this tilting causes erroneous results in estimating the original oil in place (ooip) in reservoir simulation process, and provides inadequate water flooding schemes while field development process, would affect reservoir recovery process and reserve prediction. the actual cause for the tilt of oowc is still under investigation. the difficulties in studying the oowc tilt related to the lack of flank wells intersecting the oowc. in addition, most of the available information coming from edge wells in areas of high cristal production resulting in dynamic oil water contact (owc), not oowc. this oowc differs from the dynamic owc that is related to the pressure gradient caused by oil iraqi journal of chemical and petroleum engineering university of baghdad college of engineering analytical model for detection the tilt in originally oil water contacts 52 ijcpe vol.15 no.3 (september 2014) -available online at: www.iasj.net production and subsequent pressure drop in the producing area which vary along the oil-water interface and causing the water to move with varying speeds in the different parts of the reservoir; this causes a distortion in the owc. previously, a wide explanation for the tilt was a huge regional dynamic aquifer to what recently has established the cause for the regional temperature gradient variation [1]. several theories were presented in the past to investigate the tilted oowc, but in fact none were able to account successfully for the origin of this phenomenon. however, stenger [2] shows that the geothermal gradient is a controlling parameter of the aquifer salinity and this affects the gradual change in oil-water densities. shawket g.ghaidan et al. [3] stated that capillary pressure reflects the interaction of rock and the fluids filling these pores. the measurements of capillary pressure must ideally perform in reservoir conditions to reflect the actual field analysis, but unfortunately one is extremely difficult and is usually done by injecting mercury at ambient conditions. however, the experience showed that either capillary pressure measured in the laboratory or capillary pressure converted to reservoir conditions may not match the log derived sw pc data which also has an accuracy of +/10% in best and may be as high as +/20% . [3]. anderson [4] also confirmed that the capillary pressure saturation relationship depends on the interaction of wettability, pore structure, initial saturation, and saturation history. no simple relationship exists that relates the capillary pressure determined at two different wettabilities. therefore, the most accurate measurements are made with cores that have native reservoir wettability. majid hassanizadeh et al. [5] stated that although the processes that determine the distribution of fluid phases in porous media are extremely complicated. the main theoretical and practical tool currently used to quantify the capillary pressure function is an empirical relationship between capillary pressure and saturation and as such, it lacks a firm theoretical foundation. this simple empirical model is implicitly assumed to account for all effects and processes that influence the equilibrium distribution of fluids, such as surface tension, presence of fluid–fluid interfaces, wettability of solid surfaces, grain size distribution, and microscale heterogeneities. all of these effects are essentially lumped into the capillary pressure and saturation relationship. in fact, there is ample theoretical and experimental evidence that this simple relationship is not unique, but it depends on the flow dynamics; it depends on both the history and the rate of change of saturation. the dependence of capillary pressure– saturation curves on the history of flow is known as capillary pressure hysteresis this is a well-known effect and has been the subject of extensive investigations. the dependence of capillary curves on the rate of change of saturation is due to dynamic effects. theories used in initialization of oowc due to the variance of the theories made to explain the reasons of tilted oowc, hsueh et al. [1] suggested four different methods that could be used in initializing the oowc as follows: 1initialization with capillary pressure correction: this method provides a correction term for capillary pressure added to the general definition of capillary pressure to balance the difference in oil column jalal abdulwahid al-sudani -available online at: www.iasj.net ijcpe vol.15 no.3 (september 2014) 53 thickness with respect to the free water level. 2initialization with specified water saturation: this method suggests that if there is a large saturation contrast in the vertical direction, it may cause instability at time zero of reservoir saturation initialization; this instability may extend over the course of the history match. 3initialization by equilibrium region: this method is simple in application; the reservoir area is divided into two equilibrium regions with two different owc. the disadvantage of this method is that it is not applicable to account for more than one tilt direction. 4initialization by dynamic injectionproduction method: this method suggests using pseudo injection/production wells located at the sides of the tilt to artificially create the tilted owc. the pseudo injection well is located at the side of high water column of the tilt, while the pseudo production well is located at the lower water column of the tilt. image theory the most powerful techniques in reservoir engineering is the principle of image theorem that can be applied to removing the restrictions that have been imposed on various forms of solution. the principle of image theorem says that the response of the system to a number of events is exactly equal to the sum of the responses to each of the events as if they were present by themselves. it is well known that the capillary pressure holds the fluid interfaces at their equilibrium positions unless a pressure disturbance may occur at the contacted free fluid interfaces [6]. thus, the new theory of measuring the dynamic capillary pressure under reservoir conditions suggests creating reservoir pressure drop pulse that is usually performed throughout conventional well test analysis. therefore, it is essential to formulate dynamic capillary pressure model in an appropriate way due to its importance in reservoir simulation and engineering applications; in order to reduce the complexity, the formulation of an accurate analytical dynamic capillary pressure model in which the created reservoir pressure drops moving between two different fluid mediums (oil and water) could be analyzed by treating each fluid-phase zone as explicit single-phase zone that takes its own fluid and rock properties, as already adopted by layne et al. [7]; hence, the reservoir-aquifer zones are linked across the free water level (zero capillary pressure) by a capillary transition zone that is balancing the pressure difference across the free water level. hence, the free water level could be considered as a no-flow boundary and the reservoir may behave as an infinite acting reservoir as well as the free water level still not affected by the created reservoir pressure drops. based on this principle, the pressure difference across the free water level must remain constant while the pressure transient flow period which reflects the dynamic capillary pressure across the free water level representing the initial transition zone thickness of height depends on the density difference between the oil and water. thus, the exact solution could be generated using the principle of image theorem throughout reflecting the created reservoir pressure drops at the free water level to estimate the reflected pressure drops in a manner exactly identical to the procedure used to estimate the reservoir pressure drops for a well bounded by a no-flow boundary; therefore, this solution is valid only during the pressure transient analytical model for detection the tilt in originally oil water contacts 54 ijcpe vol.15 no.3 (september 2014) -available online at: www.iasj.net flow period. hence, both of the created and the reflected pressure drops should exhibit transient flow behavior. since, based on the principle of image theorem, the exact solution to estimate the pressure difference across the free water level is exactly equal to the sum of the responses for the reservoir and aquifer zones, taking into consideration that the solution of vaneverdingen and hurst [8] for infiniteradial flow will represent the created reservoir pressure drops encountered due to oil production activity, and keith coats [9] exact solution to represent the imposed reflected pressure drops encountered at free water level. the aquifer will respond to the created reservoir pressure drops by an imposed reflected pressure drops that depend on its own water and rock properties. hence, both of the created and the imposed reflected pressure drops should exhibit transient flow behavior, as well as the created reservoir pressure drops have not reached the free water levels yet. estimation dynamic capillary pressure the main theoretical and practical tool currently used to quantify the capillary pressure function is only an empirical simple function that lacks meeting all parameters affecting capillary pressure-saturation relationship as given by eq. 1. …(1) where are the pressures exerted at the free water level by both of reservoir fluid and aquifer water zones, respectively. adding and subtracting the initial reservoir pressure ( ) to the right hand side of eq. 1 and arranging it which could be rewritten as follows; …(2) the term represents the created reservoir pressure drop behavior during transient flow period, which could be estimated using vaneverdingen and hurst [8] for infinite radial flow solution; while, represents the imposed reflected pressure drops by the aquifer zone, which could be estimated using keith [9], for two dimensional flow solution. the numerical results for a computer program prepared to estimate the pressure difference across the free water level for many different hypothetical systems show constant pressure difference behavior between the created and the reflected pressure drops during the pressure transient solutions as shown in fig. 1; however, the values of pressure difference depend entirely between the contacted rock and fluid properties (darcy’s law). fig. 1, schematic drawing shows the constant difference between the created and reflected pressure drops denoting the dynamic capillary pressure across the free water level as commonly used in reservoir performance analysis, the pressure drop behavior could be represented in dimensionless form. thus, the capillary pressure term could also be converted to dimensionless capillary pressure form. therefore, eq. 2 can be jalal abdulwahid al-sudani -available online at: www.iasj.net ijcpe vol.15 no.3 (september 2014) 55 expressed in dimensionless form as follows: ...(3) where is the dimensionless dynamic capillary pressure. hence, the dynamic capillary pressure is zero at the free water levels; thus equation 2 could be written at the water free level as follows; …(4) using van-everdingen and hurst [8], for infinite radial flow solution for the created reservoir pressure drops expressed by the following expression: …(5) where represents the dimensionless time provided by the following expression as given by john lee et al. [10] and tarik ahmed [11]: …(6) where ( and ) are the reservoir porosity and permeability ( ) are the reservoir fluid viscosity and compressibility, respectively, is the producing well radius, and ( ) is the producing time. while, the reflected pressure drops by the aquifer zone exhibit two dimensional flow in radial and vertical directions using the solution of keith coats [9], which can be written as follows: √ √ [ ] …(7) where represents the dimensionless time provided by the following expression which is written by using aquifer zone properties as follows: …(8) is dimensionless aquifer size, which is expressed as follows [9, 11]: √ √ …(9) is a constant that depends on aquifer size as given by keith coats [9]. the final form of keith coats [9] model given by (7) was arranged by al-sudani [12] to be applicable in all reservoir sizes as follows: …(10) where is the dimensionless aquifer pressure drops at free water level. …(11) substituting eqs. 5, 6, 8 and 10 in eq. 3 will generate the following expression: [ ( ) ] [ ( ) ] …(12) the values of as given by keith coats [9] behave as shown in the following expression: …(13) substituting eq. 13 in 12 yields the following: [ ( ) ] [ ( ) ] …(14) analytical model for detection the tilt in originally oil water contacts 56 ijcpe vol.15 no.3 (september 2014) -available online at: www.iasj.net simplifying eq. 14 yields the following: ( ) …(15) and; ( ) …(16) where is the effect of aquifer size on capillary transition zone that is expressed by: …(17) for further simplification, it is assumed that the displaced and displacing fluid zones have the same porosities; thus, eq. 16 could be rewritten as follows: ( ) …(18) eq. 18 provides general expression for dimensionless dynamic capillary pressure term performed under reservoir conditions. the expression can be converted to its dimensional form throughout multiplying the dimensionless values by (δp/pd): …(19) thus, the dynamic capillary pressure term could be written as follows: …(20) however, the transition zone thickness is the function of the pressure difference across the free water level and the density difference between oil and water, which is commonly expressed as given by [1 and 5] as follows: …(21) where, …(22) while and represent the initial transition zone thickness and the dynamic capillary pressure, respectively and is conversion parameter that equals = . application of this method requires only one conventional drawdown well test analysis and some simple laboratory measurements for oil and water viscosity and compressibility at initial reservoir conditions to estimate accurately the dynamic capillary pressure rather than performing some complicated laboratory measurements for capillary pressure which in due course cannot be done at reservoir conditions. results and discussion the presented model given in eq. 20 which is derived from the simple definition of capillary pressure shown in eq. 1 involves all rock and fluid properties for both of reservoir and aquifer zones. moreover, all of the properties can be measured under reservoir conditions as the reservoir permeability can be obtained from well test analysis; while, the aquifer’s zone permeability can be estimated from injectivity test or using voigt’s [13] model. then, both of reservoir and aquifer viscosity and compressibility can be estimated from pvt data at actual reservoir pressure and temperature. since, the developed model reflects the real interaction between all rock and fluid properties, and will eliminate the logging analysis and coring works in determining the fluid contact positions. figs 2, 3 and 4 were built for a hypothetical reservoir-aquifer system as given in table 1; the effects of jalal abdulwahid al-sudani -available online at: www.iasj.net ijcpe vol.15 no.3 (september 2014) 57 reservoir and aquifer permeabilities, reservoir thickness and aquifer size properties were verified to take full knowledge for the controlling parameters on dynamic capillary pressure. investigating these figures show the emphasized effect for reservoir characteristics in increasing the dynamic capillary pressure which led for thicker transition zone than that observed for aquifer characteristics. table 1: reservoir-aquifer hypothetical system variables fig. 2 fig. 3 fig. 4 , b/d 5000 5000 5000 , md variable 600 600 , md variable 120 120 , cp 2 2 2 , cp 1 1 1 , ib/ft 3 52.1 52.1 52.1 , lb/ft 3 63.2 63.2 63.2 , ft 90 variable 90 , ft 80 80 80 ,rb/stb 1.2 1.2 1.2 ,rb/stb 1.01 1.01 1.01 , psi -1 8*10 -6 8*10 -6 8*10 -6 , psi -1 2*10 -6 2*10 -6 2*10 -6 , ft 0.25 0.25 0.25 0.2 0.2 0.2 0.2 0.2 0.2 s 0.0 0.0 0.0 0.005 0.005 variable 0.2 0.2 0.2 it is noticed that the aquifer permeability has an adverse effect on dynamic capillary pressure compared with the effect of reservoir permeability as shown in fig. 2; this conclusion gives an accurate thorough explanation for the variation in oil water contact positions than previously acknowledgment, which only relates to the phenomenon for reservoir permeability variation. the reason for the shortage explanation of tilt oowc, can be attributed for unavailable exact theoretical model in the literature to estimate the dynamic capillary pressure that involve all influencing reservoir and aquifer properties. while figs 3 and 4, respectively, show the adverse effect for reservoir thickness and aquifer sizes on dynamic capillary pressure. this can be attributed for the reduction in reservoir pressure props. hence, it can be stated that same effects for both reservoir and aquifer’s fluids properties (viscosity and compressibility) on dynamic capillary pressure, as both of them affect the created and imposed reflected pressure drops. fig. 2: reservoir and aquifer permeability effects on capillary pressure fig. 3: effect of reservoir thickness on capillary pressure meanwhile, the tilt in originally oilwater contact has been studied for iraqi carbonate oil field producing from two main reservoirs under different reservoir-aquifer properties as given in appendix-a; the generated results analytical model for detection the tilt in originally oil water contacts 58 ijcpe vol.15 no.3 (september 2014) -available online at: www.iasj.net from the current model were compared with the actual field data that showed very identical results. fig. 4: effect of dimensionless aquifer size on capillary pressure conclusions the presented model provides the real measurements and full explanation without any limitation for the tilts in oowc under actual reservoir conditions. this method uses only the conventional well test analysis performed in reservoir. moreover, the theory has a lot of advantages which could be stated as follows; 1the analysis provides the actual measurements of the tilt in oowc. 2it is directly applied using reservoir pressure transient analysis and no experimental laboratory works needed, since it is a cost effective procedure when performing some complicated experiments. 3this method could be applied in any position within the entire reservoir area, since it could provide the tilt of oowc in all directions. 4the model will assist in accurately evaluating the originally hydrocarbon in place throughout determining the transition zone intervals and saturation distribution. 5the model can be considered an easy tool in estimating the oowc in reservoir simulation studies. nomenclature symobile difintion unit bo oil formation volume factor rb/stb bopd barrel oil per day. total aquifer compressibility psi -1 total reservoir compressibility psi -1 fwl free water level conversion constant =32.2 oil reservoir column thickness, ft transition zone thickness, ft aquifer zone permeability in horizontal direction. reservoir zone permeability aquifer zone permeability in vertical direction. absolute aquifer zone permeability dimensionless aquifer size. capillary pressure, psi dimensionless capillary pressure initial reservoir pressure, psi aquifer pressure at fwl psi reservoir pressure at fwl psi dimensionless pressure drop dimensionless reservoir pressure drop dimensionless reflected pressure drop occurs in the free water level modified dimensionless reflected pressure drop occurs in the free water level oil flow rate, stb/day well radius, ft jalal abdulwahid al-sudani -available online at: www.iasj.net ijcpe vol.15 no.3 (september 2014) 59 t production time, days dimensionless time dimensionless time calculated using aquifer zone properties dimensionless time calculated using reservoir zone properties aquifer size effect on capillary zone. greek symbols μo oil viscosity cp μw water viscosity cp ρo oil density ib.m/ft 3 ρw water density ib.m/ft 3 density difference ib.m/ft 3 reservoir porosity aquifer porosity references 1hsueh p.t., pham t.r. and buhulaigah e.h.”a review of different initialization and history matching a reservoir model with tilted oil water contact”.spe-53373 – 1999. 2stenger b.a.” regional temperature gradient: a key to tilted oowc”. spe-53197, 1999. 3shawkat g. ghaidan, bertrand m. thiebot and douglas a boyd.”modeling and validation of initial water saturation in the transition zone of carbonate oil reservoirs”. spe88756, 2004. 4anderson,w.g.: “wettability literature survey – part 4: effects of wettability on capillary pressure”, jpt (oct. 1987) 12831300. 5hassanizadeh sm, oubol oung, sabine manthey;” laboratory experiments and simulations on the significance of non-equilibrium effect in the capillary pressuresaturation relationship”, unsaturated soils: experimental studies, springer proceedings in physics volume 93, 2005, pp 3-14. 6al-khalifah, a.j.a.; odeh, a.s.: "well test analysis in oil reservoirs with gas cap and/or water aquifer". spe-19842, paper presented at the 64 th annual technical conference and exhibition of spe held in san antonio,tx, oct.8-11, 1989. 7layne m.a., numbere d.t. and koederitz l.f.: "analytical solution to predict the performance of gas reservoirs under water drive" spe-26669, paper presented at 68 th annual technical conference and exhibition of spe held in houston, texas 3-6 oct. 1993. 8van-everdingen, a.f. and hurst, w.; "the application of laplace transformation to flow problems in reservoirs", trans. aime (1949) vol. 186, 305. 9keith h. coats; "a mathematical model water movement about bottom-water drive reservoirs.” spe-160, paper presented at 36 th annual fall meeting of spe, oct.811, 1961, in dallas. 10 john-lee, john b. rollins, john p. spivey “pressure transient testing” spe textbook series, texas.2003. 11tarik ahmed, paul d. mckinney; "advance reservoir engineering" elsevier, 2005, chapters (1 and 2). 12 j.a. al-sudani,” prediction the future performance of reservoir fluids movement under combined drive mechanism” ph.d. thesis submitted to uinv. of baghdad, pet. eng. dept. may, 2009. 13voigt, h.d. and astl, a.; "determination of permeability from responses in aquifer wells". spe-16996, 1987. http://link.springer.com/search?facet-author=%22s.+majid+hassanizadeh%22 http://link.springer.com/search?facet-author=%22oubol+oung%22 http://link.springer.com/search?facet-author=%22sabine+manthey%22 http://link.springer.com/book/10.1007/b138014 http://link.springer.com/book/10.1007/b138014 http://link.springer.com/bookseries/361 http://link.springer.com/bookseries/361 analytical model for detection the tilt in originally oil water contacts 60 ijcpe vol.15 no.3 (september 2014) -available online at: www.iasj.net appendix-a: field example: it is an iraqi carbonate oil field given by al-sudani [12] produced from two main reservoirs under bottom water drive aquifer. the reservoir and aquifer zones properties are listed as shown in tables a-1 and a-2, respectively. other reservoir and aquifer fluids properties are as follows; (co=8.95*10 6 psi -1 , µo=0.65 cp, bo=1.46 rb/stb) and (cw=2.5*10 -6 psi -1 , µw=0.705 cp, bw=1.02 rb/stb), app. oil density=53.4 ib/ft 3 , approximate water density=63 ib/ft 3 . approximate dimensionless aquifer size = 0.005. four wells penetrating the main reservoirs were selected in this test representing the west and east sides of the reservoir; the flow rates of these wells are listed in table a-3. required: estimation of capillary transition zone thickness to predict the tilt in oowc. table a-1: main reservoir characteristics unit a d net thickness (ft) 25 125 0.21 0.24 kmd 580 1115 table a-2: aquifer characteristics west east unit a d a d kw – md 1381 2297 305 1165 0.32 0.23 0.14 0.2 thickft 92 100 43 110 table a-3: well production of oil in units a and d (bopd) east region west region reservoir 4100 8300 a 5155 7875 d solution: a computer program on excel sheet was prepared to be used in estimating dynamic capillary pressures and the transition zone thickness based on the derived analytical model represented by eqs. 18, 20 and 21; the results are listed as shown in table a-4; these results obtained by the new model show high tilted oowc that exists between west-east regions for units (a and d); the results confirm this carbonate field of owc characteristic and may provide the best explanation for the tilted oowc in some carbonate reservo irs which is still under investigation. table a-4: calculated values of capillary pressure and transition zone thickness (a); east (a); west (d); east (d); west 1.15379 4.63114 2.7346 4.2977 , psi 43.716 355.221 13.553 32.539 , ft 20.3836 165.630 6.3195 15.1722 the results of this field data exactly show the titled in originally oil-water contact from west to east, especially in reservoir unit (a) due to the high variation in rock and fluid properties with the aquifer, compared with what is observed in reservoir unit (d). the results confirm the actual tilts in oowc from west to east in both units; therefore, the new methodology may explain the reasons beyond this phenomenon which is still under investigation by some authors such as hsueh [1]. jalal abdulwahid al-sudani -available online at: www.iasj.net ijcpe vol.15 no.3 (september 2014) 61 iraqi journal of chemical and petroleum engineering vol.17 no.4 (december 2016) 113123 issn: 1997-4884 the effect of in-situ stress on hydraulic fractures dimensions mohammed al humairi 1 and hassan abdul hadi 2 1 college of engineering missan university 2 petroleum engineering department college of engineering university of baghdad abstract understanding of in-situ stress profiles and orientations plays a vital role in designing a successful hydraulic fracturing treatment. this paper is an attempet to examine the effect of lithology and in situ stress on geometery of hydraulic fractures. a hydraulic fracturing design simulator software called fracpropt with various capabilities for designing most of hydraulic fracture was used for simulate and optimize the hydraulic fracturing. for studying purpose, three different cases of stress gradient contrast between different formations are considered in this study (0.4, 0.5 and 0.75 psi/ft). the results obtained from the simulator showed that lithologies surrounding the pay zone have an effect on the fracture’s height, width, and length. also, maximum height is achieved when the stress contrast between the pay zone and the surrounding layers is very small. key words: petroleum, hydraulic fractures, stress, design. introduction stimulation of oil bearing reservoirs by hydraulic fracturing included, injection of a high viscosity fracturing fluid down a wellbore at a rate greater than the fluid leak-off rate so that it builds-up pressure to overcome the tensile strength of the reservoir rock and establish an effective communication between the reservoir and the wellbore. the effect is the initiation and propagation of fractures on a plane perpendicular to the least principal stress [1]. today hydraulic fracturing treatment has extended to involve other applications such as:  assisting in secondary and tertiary recovery processes such as water-, fire-, and steam flood operations, to improve injectivity and sweep efficiency.  assisting in the injection or disposal of waste water and drill cuttings.  bypassing formation damage (skin effect) due to drilling and completion operations by means of a relatively small fracture in order to increase productivity [2].  increasing ultimate production from low permeability formations such as tight gas sandstones by means of massive treatments that generate longer fractures than those created for bypassing skin effect.  tackling the problem of sand production in poorly consolidated or unconsolidated high permeability formations using coated resin and university of baghdad college of engineering iraqi journal of chemical and petroleum engineering the effect of in-situ stress on hydraulic fractures dimensions 114 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net reducing wellbore pressure gradient [3]. there are many parameters that controlled the success of this process such as the fracture dimensions – fracture half length, width and height – as well as proppants, fluids, treatment schedule etc. the fracture geometry then depends on several other factors like in-situ stress fields and modulus contrasts surrounding the formation [4]. the in-situ stress field is a function of geology or the lithological sequence [5]. this paper is an investigation of effect of insitu stresses on design of hydraulic fractures geometry. three different lithology sequences are considered in this investigation. fracture geometry is expressed in term length, width, and height. fracture geometries are modeled in three dimensional with assumption that the reservoir rock is homogeneous, isotropic and linearly elastic. with aid of fracture simulator , a complete analysis of each treatment related to production enhancement, economic estimation are also performed. well data table 1 and figure 1 presented the detailed information of well configuration that being to be fractured. table1: wellbore configuration drilled hole length (ft) top md (ft) bottom md (ft) open hole bit diam (in) effective diam (in) 8000 0 2000 open hole 14.375 14.375 750 2000 8750 open hole 12.250 12.250 casing length (ft) top md (ft) bottom md (ft) casing od (in) weight (lb/ft) id (in) 2000 0 2000 cemented 13.375 54.500 12.615 8750 0 8750 cemented 9.625 40.000 8.835 surface line/tubing length (ft) top md (ft) bottom md (ft) surf line/tubing od (in) weight (lb/ft) id (in) 8500 0 8500 tubing 3.500 9.30 2.992 perforation intervals top md (ft) bottom md (ft) top tvd (ft) bottom tvd (ft) diameter (in) number of perforations 8600 8750 8600 8750 0.380 50 path summary segment type length (ft) md (ft) tvd (ft) deviation (deg) ann od (in) ann id (in) pipe id (in) tubing 8500 8500 8500 0.00 0.000 0.000 2.992 casing 100 8600 8600 0.00 0.000 0.000 8.835 directional survey build rate (deg/100 ft) turn rate (deg/100 ft) dl sev. (deg/100 ft) md (ft) inclination (deg) azimuth (deg) tvd (ft) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 http://www.iasj.net/ mohammed al humairi and hassan abdul hadi -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 115 fig. 1: wellbore schematic view formation data case i the lithology sequence of this treatment is a dolomite formation (as pay zone with stress gradient of 0.8 psi/ft) surrounded by granite beds from top and bottom(with stress gradient of 1.2 psi/ft). the stress gradient contrast is 0.4 psi/ft. tables 2 and 3 presents the required data of this lithological sequence. case ii the lithology sequence of this treatment is a sandstone formation (as pay zone with stress gradient of 0.5 psi/ft) surrounded by limestone beds from top and bottom (with stress gradient of 1 psi/ft). the stress gradient contrast is 0.5 psi/ft. tables 4 and 5 presents the required data of this lithological sequence. case iii the lithology sequence of this treatment is a sandstone formation (as pay zone with stress gradient of 0.75psi/ft) surrounded by limestone beds from top and bottom (with stress gradient of 1.5 psi/ft).the stress gradient contrast is 0.75 psi/ft. tables 6 and 7 presents the required data of this lithological sequence. the mechanical, chemical ,and thermal properties of different layers that included in the study can be shows in table 8. table 2:reservoir layer parameters 1 for case i layer d (ft) h (ft) rock type k (md) ct (ft/min 1/2 ) stress (psi) stress gradient (psi/ft) 1 0.0 8000 granite 0 0 9600 1.200 2 8000.0 750 dolomite 2.51e-02 1.860e-04 6700 0.800 3 8750.0 1750 granite 0 0 10500 1.200 http://www.iasj.net/ the effect of in-situ stress on hydraulic fractures dimensions 116 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net table 3:reservoir layer parameters 2for case i layer e (psi) ν fracture toughness (psi∙in 1/2 ) composite layering effect pay zone 1 1.0e+07 0.20 1000 25 no 2 1.0e+06 0.25 500 1.00 yes 3 1.0e+07 0.20 1000 25 no table 4: reservoir layer parameters 1 for case ii layer d (ft) h (ft) rock type k (md) ct (ft/min 1/2 ) stress (psi) stress gradient (psi/ft) 1 0.0 8000 limestone 0 0 8000 1.000 2 8000.0 750 sandstone 0.0251 1.860e-04 4188 0.500 3 8750.0 1750 limestone 0 0 8750 1.000 table 5: reservoir layer parameters 2 for case ii layer e (psi) ν fracture toughness (psi∙in 1/2 ) composite layering effect pay zone 1 3.0e+07 0.30 500 25 no 2 1.0e+06 0.20 1000 1.00 yes 3 3.0e+07 0.30 500 25 no table 6: reservoir layer parameters 1 for case iii layer d (ft) h (ft) rock type k (md) ct (ft/min 1/2 ) stress (psi) stress gradient (psi/ft) 1 0.0 8000 limestone 0 0 12000 1.500 2 8000.0 750 sandstone .0251 1.860e-04 6281 0.750 3 8750.0 1750 limestone 0 0 13125 1.500 table 7: reservoir layer parameters 2 for case iii layer e (psi) ν fracture toughness (psi∙in 1/2 ) composite layering effect pay zone 1 3.0e+07 0.30 500 25 no 2 1.0e+06 0.20 1000 1.00 yes 3 3.0e+07 0.30 500 25 no table 8: phyiscal and thermal rock properties rock type specific gravity specific heat (btu/lb·°f) thermal conductivity (btu/ft·hr·°f) sandstone 2.65 0.26 2.57 limestone 2.72 0.21 0.91 dolomite 2.86 0.21 0.91 granite 2.7 0.2 1.74 http://www.iasj.net/ mohammed al humairi and hassan abdul hadi -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 117 fracture fluid data as fracturing fluid, schlumberger based fluid yf840 ht w/10 lb/k was selected because it has 200 cp apparent viscosity at 40 sec -1 (estimated shear rate in the fracture) after about 2 hours of exposure to the reservoir temperature. this was also the first amongst the qualified fluids selected by the fracpropt for the given set of constraints. fluid loss, thermal properties and cost for yf840 ht w/10 lb/k fluid are presented in table 9. proppant the selected proppant is 20/40 arizona sand, based on the highest fracture conductivity and proppant permeability. properties of this proppant are presented in table 10. table 9: fluid loss, thermal properties and cost for schlumberger’s yf840 ht w/10 lb/k thermal conductivity 0.320 btu/ft·hr·°f wall building coefficient 2.45e-04 ft/min 1/2 specific heat 1.00 btu/lb·°f spurt loss 0.0178 gal/ft 2 specific gravity 1.000 unit cost 5 $/gal table 10: properties of 20/40 arizona sand (propant) cost 0.05 $/lb diameter 0.027 in bulk density 100.00 lbm/ft 3 proppant type sand packed porosity 0.426 proppant coating none specific gravity 2.79 turbulence coeff a 1.09 turbulence coeff b 0.082 results and discussion case i figure 2 depicts the variation of fracture dimensions with respect to time. at the beginning of the treatment, width, length and height grow quickly. this can be attributed to the fact that the fracture is growing in the dolomite layer, which has a stress gradient less than the adjacent granite layers. fracture dimensions are affected by the gradient stresses and depth of the granite layers. fracture lower height and width below the perforations are smaller than fracture upper height and width above the perforations because the first set is under a higher stress magnitude because of its depth. in this case of hydraulic fracturing one formation with low stress concentration is located between two formations with a higher stress concentration. as it can be seen in figure 3, the fracture exhibits its maximum length and width in the middle of the dolomite formation, i.e. the pay zone. on the other hand, fracture conductivity decreases in the pay zone as the distance from the wellbore increases. by the same way, conductivity decreases from the target dolomite layer to the bounding granite layers as one move along the height axis. figure 4 shows the concentration of the proppant in the fracture as it relates to fracture length and stress concentration. the major pay zone is a dolomite formation located at 8000 ft. the maximum propagation length is located in the middle of this formation. a fracture length of 1478 ft can be observed. the fracture has a maximum propagation length in the middle where the dolomite formation with the lowest stress concentration is located. http://www.iasj.net/ the effect of in-situ stress on hydraulic fractures dimensions 118 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net fig. 2: fracture dimensions for case i fig. 3: fracture geometry, width profile, and fracture conductivity for case i fig. 4: fracture geometry, width profile, and concentration of proppant in fracture for case i http://www.iasj.net/ mohammed al humairi and hassan abdul hadi -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 119 case ii in figure 5 the effect of the stress concentration on the fracture propagation can be seen. figure 5 shows the fracture dimensions as functions of time. all the dimensions increase with increase time, but it can be seen that the fracture grows in length faster than in height or width. figure 6 shows the concentration of the proppant in the fracture as it relates to fracture length and stress concentration. the major pay zone is a sandstone formation located at 8000 ft. the maximum propagation length is located in the middle of this formation. a fracture length of 1554 ft can be observed. the fracture has a maximum propagation in the middle where as the sandstone formation with the lowest stress concentration is located. figure 7 shows fracture conductivity values inside the fracture with the values decreasing as distance increases from the wellbore to the tip of the fracture along the length axis and also as one move along the height axis away from the sandstone pay zone. fig. 5: fracture dimensions for case ii fig. 6: fracture geometry, width profile, and fracture conductivity for case ii http://www.iasj.net/ the effect of in-situ stress on hydraulic fractures dimensions 120 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net fig. 7: fracture geometry, width profile, and concentration of proppant in fracture for case ii case iii in figure 8 the effect of the stress concentration on the fracture propagation can be seen for case iii, which has a zero stress gradient. figure 8 shows the fracture dimensions with respect to time. all the dimensions increase with time. the fracture length however shows more growth compared to the height or width. figure 9 shows fracture conductivity values inside the fracture with the values decreasing as distance increases from the wellbore to the tip of the fracture along the length axis and also as one move along the height axis away from the sandstone pay zone. figure 10 shows the concentration of the proppant in the fracture as it relates to fracture length and stress concentration. the major pay zone is a sandstone formation located at 8000ft. the fracture has a maximum propagation length n the middle where as the sandstone formation with the lowest stress concentration is located. a fracture length of approximately 1542ft can be observed. as observed in table 11 and figure 11, in-situ stress and young modulus differences between the pay zone and the surrounding formations have an important effect on fracture containment or restriction. we observe that if the young’s modulus and the stress gradient of the encompassing layers is greater than the pay zone, it is possible to contain the fracture height within the pay zone. as for fracture length, case ii and case iii have same lithology sequence but with different stress gradient contrast between the pay zone and the encompassing layers. stress gradient contrast in case ii is 0.5 psi/ft with fracture length of 1554 ft. stress gradient contrast in case iii is 0.75 psi/ft with fracture length of 1542 ft. these values show small effect of stress contrast on fracture length. another observation that related to proppant concentration. the proppant concentration in case ii is 1.31 lb/ft 2 with fracture width of 0.97 in, while proppant concentration in case iii is 1.63 lb/ft 2 with fracture width of 0.99 in. as result, a small increases in the fracture width is achieved when increasing the proppant concentration in the fracture. the fracture height in all the cases was 750 ft, which means that the pay zone will be coverage by 100%. http://www.iasj.net/ mohammed al humairi and hassan abdul hadi -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 121 this is due to selection of the right kind of fracturing fluid yf840 ht w/10 lb/k from schlumberger and 20/40 arizona sand, which gives the highest fracture conductivity and proppant permeability thus giving an optimum output. finally, the economic evaluation in term of net present value (npv) showed the lower value at lower stress gradient contrast (case i) as shown in table 11. also the highest npv value for case ii ($86.166b) where the stress gradient contrast is 0.5 psi/ft. thus, for an optimum treatment, the knowledge of stress differences between the pay zone and the bounding layers play a crucial part. fig. 8: fracture dimensions for case iii fig. 9: fracture geometry, width profile, and fracture conductivity for case iii http://www.iasj.net/ the effect of in-situ stress on hydraulic fractures dimensions 122 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net fig. 10: fracture geometry, width profile, and concentration of proppant in fracture for case iii table 11: comparison of results fracture parameters case 1 case 2 case 3 stress gradient (psi/ft) 0.8 0.5 0.75 stress gradient contrast (psi/ft) 0.4 0.5 0.75 fracture length (ft) 1478 1554 1542 propped length (ft) 1441 1511 1503 total fracture height (ft) 750 750 750 total propped height (ft) 732 730 731 average fracture width (in) 1.02 0.97 0.99 average proppant concentration (lb/ft 2 ) 1.95 1.31 1.63 dimensionless conductivity 16.77 15.36 13.81 npv (m$) 71397 86166 75330 cumulative oil production (mbbls) 1576.711 1860.378 1654.363 fig. 11: results comparison plot http://www.iasj.net/ mohammed al humairi and hassan abdul hadi -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 123 conclusions based on the obtained results, the following conclusions are outlined: 1. after analyzing the effect of in-situ stress differences on the fracture geometry, it is clear that this is a crucial factor controlling fracture height, length and width. stress gradient contrast is responsible for containment or restriction of fracture growth. 2. the selection of a right kind of fracturing fluid and proppant will help you achieve 100% pay zone coverage. 3. the stress gradient contrast between the pay zone and the surrounding layers is inversely proportional to the dimensionless fracture conductivity. 4. also, the fracture half length increased as the stress gradient decreased. 5. in all the three cases examined , there was good fracture containment as a result of the high young’s moduli of the surrounding layers. 6. the net present value (npv), which is an economic optimization parameter for the treatment design is seen to show some dependence on the stress gradient. specifically, as the stress gradient increased from 0.5 through 0.75 to 0.8 psi/ft, the npv decreased from $86.166b, $75.33b and $71.397b respectively. nomenclature e young’s modulus, psi  poisson’s ratio, psi w width of fracture, in. l length of fracture, ft h height of fracture, ft c leakoff coefficient, ft/min 1/2 ct total leakoff coefficient, ft/min 1/2 d size of the tube, in. k permeability, md id internal diameter, in. od outside diameter, in. md measure depth, ft tvd true vertical depth, ft npv net present value, m$ roi rate of investment, % pi productivity index, dimensionless references 1. shah, s. “pe – 5423 advanced stimulation class notes”. mpge, university of oklahoma, fall 2008, norman. 2. fracpropt v10.3.pinnacle servicesn help files, 2007. 3. zillur rahim and mohammed y. al-qahtani. “sensitivity study on geomechanical properties to determine their impact on fracture dimensions and gas production in the khuff and prekhuff formations using a layered reservoir system approach, ghawar reservoir, saudi arabia” spe paper 72142 prepared for presentation at the spe asia pacific improved oil recovery conference held in kuala lumpur, malaysia, 8– 9 october 2001. 4. r.b. willis, j. fontaine, l. paugh, and l. griffin. “geology and geometry: a review of factors affecting the effectiveness of hydraulic fractures” spe paper prepared for presentation at the 2005 spe eastern regional meeting held in morgantown, m.v., 14-16 september 2005. 5. h. gu and e. siebrits. “effect of formation modulus contrast on hydraulic fracture height containment” spe paper prepared for presentation at the 2006 spe international oil and gas conference and exhibition in china, beijing, 5-7 december 2006. 6. e.p. lolon and m.j. mayerhofer, garcia and d.a.durey, a.c. byrd and r.d. rhodes. integrated fracture and production modeling study in the lower cotton valley sands , northern louisiana 2008. http://www.iasj.net/ iraqi journal of chemical and petroleum engineering vol.15 no.1 (march 2014) 2332 issn: 1997-4884 structure rheology of polyethylene oxide solution talib omer kashmola * and estabraq saad kamil * chemical engineering department-college of engineeringuniversity of al-nahrain abstract intrinsic viscosities have been studied for polyethylene oxide in water which has wide industrial applications. the polyethylene oxide samples had two different structures, the first one was linear and covers a wide range of molecular weight of 1, 3, 10, 20, 35, 99, 370, 1100, 4600, and 8000 kg/mol and the second one was branched and had molecular weights of 0.55 and 40 kg/mol. intrinsic viscosities and huggins constants have been determined for all types and molecular weights mentioned above at 25ºc using a capillary viscometer. the values of mark-houwink parameters (k and a) were equal to 0.0068 ml/g and 0.67 respectively, and have not been published for this range of molecular weight in as yet. key words: polyethylene oxide, intrinsic viscosity, huggins constants, markhouwink parameters. introduction polyethylene oxide resins are high molecular weight polymers having the common structure: (och2ch2)n in which n, is the degree of polymerization, ranges from 2000 to over 100,000 [1]. with a molecular formula of [2]: c2n+2h4n+6on+2 low molecular weight (mwt <1,000) pegs are viscous and colorless liquids, while higher molecular weight pegs are waxy, white solids with melting points proportional to their molecular weights to an upper limit of about 67°c [3], and a flash point of (182287°c) [2]. polyethylene oxide, being a polyether, strongly hydrogen, bonds with water. it is non-ionic and undergoes salting-out effects associated with neutral molecules in solution of high dielectric media. salting-out effects manifest themselves in depressing the upper temperature limit of solubility, and in the reducing the viscosity of both the dilute and concentrated solutions of the polymers. poly (ethylene oxide) (peo) is one of the most intensely studied polymers in current materials science and biotechnology because of not only its unique behaviors in solution but also its wide applications [4, 5]. the key properties of peo are its a soft semi-crystalline thermoplastic that displays a lot of interesting properties and finds many applications due to the wide range of molecular weight in which it is commercially available iraqi journal of chemical and petroleum engineering university of baghdad college of engineering structure rheology of polyethylene oxide solution 24 ijcpe vol.15 no.1 (march 2014) -available online at: www.iasj.net (10 2 –8*10 6 g/mol), chemical stability, solubility both in water and many organic solvents, non-toxicity, rapid clearance from the body, lack of immunogenicity and a food and drug administration (fda) approval for internal consumption. films of high molecular weight peo are tough, ductile, heat-sealable, and because of their high degree of crystallization, resist well to atmospheric moisture [6]. additionally, architectures based on nonlinear peo have recently become a focus of scientific interest, due to their branched structures and unique rheological property [7], and their intriguing potential for biomedical and pharmaceutical applications, for instance as multivalent pegylation reagents also, it has recently found increasing use as a conducting medium in light-weight, high energy polymer batteries [8], as well as for solid polymer electrolytes [9]. star-shaped peos bear multiple functional end groups adjustable by the number of arms and thus exhibit higher attachment capacity and higher capability for ion-complication in comparison with their linear analogues, combined with reduced degree of crystallization [10]. star polymers have attracted much attention because of their branched structures and unique rheological property [11, 12], and a very recent review article summarizes the importance of star-shaped peos for a variety of purposes [13]. two fundamentally different approaches for the synthesis of star polymers can be distinguished: the ‘arm-first’ and the ‘core-first’ procedure. the ‘arm-first’ strategy relies on deactivation of living peo chains by reaction with multifunctional electrophiles. in this manner welldefined star polymers with defined molecular weight of the arms and predetermined functionality can be synthesized. for instance, grafting onto cyclophosphazenes resulted in sixand twelve-arm peo stars [14]. multiarm peo-stars have also been prepared by attachment of peo chains to different types of dendrimers. the ‘arm-first’ approach, however, requires additional separation of the resulting star-shaped polymer from the linear ‘arms’, which commonly have to be used in excess. moreover, the arms in such star polymers can only be functionalized via protected functional initiators. in contrast, by the ‘core-first’ approach the growing polymer chains introduce multiple alkoxides that can be functionalized subsequent to the polymerization [15]. lee et al., and allen et al., [16, 17] polyethylene oxides biocompatibility and protein adsorption inhibitor capacity make peo a good candidate for the development of a new drug delivery medicine. villain et al., [18] polyethylene oxide can be used to substitute some biopolymers as implant for tissue replacement or augmentation. dormidontova, [19] the specific chemical structure of peo, ho [(ch2)n with n , confers to this polymer very unusual interactions with water. indeed, while poly (mthylene oxide) with n = 1 and poly (butylenes oxide) with n = 3, are both hydrophobic and insoluble in water, peo is known as the simplest hydrosoluble hydrocarbon polymer, regarding its chemical structure. its solubility in water originates from the competition between peo–water and water– water hydrogen bonding, delicately balanced by hydrophobic interactions induced by the ethylene components. the rupture of hydrogen bonds with increasing temperature is responsible for the decrease of its solubility upon heating, lower critical solution temperature behaviour. daoust and st cyr, [20] near room temperature, the water solubility of talib omer kashmola and estabraq saad kamil -available online at: www.iasj.net ijcpe vol.15 no.1 (march 2014) 25 peo is found to depend also on the polymer concentration. indeed, water is a good solvent at low concentration and high temperature while it becomes a bad solvent at intermediate concentration, close to the critical concentration gray and armand, [21]; wright, [22] peo is used for applications requiring high cation solvation and good electrochemical stability such as solid electrolytes used in lithium polymer cells, but surprisingly, it appears to be fragile and very sensitive to thermal [23], photochemical [24, 25], and ultrasound [26, 27]. madras and mccoy, [28] they investigated the degradations in the bulk and in solution for polymer solutions, thermal and photochemical degradations have been observed for temperatures higher than 50ºc and for samples exposed to irradiation corresponding to natural outdoor aging (λ > 300 nm). both degradation processes induce the formation of format and ester groups. the release of formic acid ions (hcoo−) is responsible for a drastic decrease of the ph, leading to a random chain scission. in the case of ultrasound degradation, chain scission is due to intense shear stresses arising from the collapse of transient cavitations bubbles. contrary to thermal and photochemical degradations, the resulting rupture of covalent bonds occurs preferentially in the middle of polymer chains, up to molecular weight of about 2 *10 4 g/mol below which the polymer will not undergo scission. it has to be noticed that sonication produces heat, leading to some local increases of temperature and consequently associated thermodegradation, even if the temperature of the sample is externally controlled. consequently, peo in water requires controlled and precise conditions when handling, which make it a delicate polymer to work with. these difficulties are enhanced concerning high molecular weight peo due to a more complex structural organization of the macromolecule. hammouda et al., [29] low molecular weight peo obtained from controlled polymerization techniques, high molecular weight peo are obtained from condensation of low molecular weight peo through multifunctional agent, leading to form both hydrophobic regions and branched structures. proposes that peo solutions below 70◦c are phase-separated systems in which aggregates form a concentrated phase that coexists with a dilute phase of swollen coils. such phase separation has been ascribed to the upper critical solution temperature behaviour of peo solutions. however, a recent small angle neutron scattering investigation of peo aqueous solutions has contradicted this hypothesis, this study pointed out chain ends effects on the clustering in peo solutions with a molecular weight of 4*10 4 g/mol. despite the fact that end groups represent only one unit per 1,000 units, this study has shown that the ability of the peo to aggregate is enhanced in the presence of non-polar ch3 groups at both ends of the polymer chain while it is strongly reduced in the case of chains end-capped by polar oh groups. polik [30] and duval, [31] they proposed the contribution of hydrophobic interactions, seems to be determinant when peo chains are endcapped by non-polar groups and would lead to polymer aggregation through – ch2–ch2– groups belonging to the chain and end groups. however, this interpretation cannot explain the ability of peo chain end-capped with oh groups to form clusters. several works refer to shear-induced aggregation in peo aqueous solutions. structure rheology of polyethylene oxide solution 26 ijcpe vol.15 no.1 (march 2014) -available online at: www.iasj.net intrinsic viscosity the viscosity of a polymer solution (η) is higher than that (η o ) of the pure solvent at a specified temperature and the increase in medium viscosity on dissolving the polymer in the solvent is a function of both molecular weight and concentration of the polymer solute [32]. if the polymer solution is very dilute, then the viscosities of the solvent and the solution at a given temperature would be proportional to their flow times in a given capillary viscometer such that the relative viscosity η r expressed by the ratio (η / η o ) would be given by the flow time ratio (t / t o ), where t o is the flow time of a given volume of the solvent and t is the flow time of the same volume of solution respectively. the parameter called specific viscosity, η sp as defined by η sp = (η – η o ) / η o = (t – t o ) / t o , where specific viscosity per concentration equal to reduced viscosity, and intrinsic viscosity is [32]:   red c  0 lim   …(1) intrinsic viscosity [η] may be regarded as a measure of the specific hydrodynamic volume of a dissolved polymer at infinite dilution c 0 [33]. the intrinsic viscosity measured in a specific solvent is related to the molecular weight m, by the mark – houwink equation [34, 35].   akm …(2) where k and a are mark-houwink constans that depend upon the type of polymer, solvent, and the temperature of the viscosity determinations [34]. the unit of intrinsic viscosity is an inverse concentration [36]. the concentration dependence of the reduced viscosity can be related to the following equations of huggins [37, 38].     ck c sp 2    …(3) where k  , is constant for a given polymer–solvent–temperature systems [39]. experimental work materials the studied polymer was polyethylene oxide with different molecular weights and types dissolved in water (with conductivity < 0.5 μs/cm). the samples of average molecular weights 1, 3, 10, 20, and 35 kg/mol were obtained from physical chemistry institute, mainz university, germany. the samples of average molecular weights 100 , 300 , 1000 , 4000 , and 8000 kg/mol were purchased from sigma – aldrich company , germany , and the branched polyethylene oxide of molecular weight 0.55 and 40 kg/mol was purchased from creative pegworks, winston salem, nc, usa , all samples used as received. the molecular weights given by sigma – aldrich checked by viscometric measurements at 30 ºc because the samples specifications were quite imprecise. the various molecular weights of polyethylene oxide were used in the present work to see the difference in their behaviors and how the higher molecular weights are more effective than the lower ones for industrial application, especially for drug reduction [40-44]. the polymer was studied to determine its intrinsic viscosity, critical molecular weight, and viscoelastic properties. dissolving process for capillary viscometry the dissolving of polymers was normally carried out talib omer kashmola and estabraq saad kamil -available online at: www.iasj.net ijcpe vol.15 no.1 (march 2014) 27 by taking a certain amount of each molecular weight to obtain a solution with specific viscosity ηsp of about 1. from the starting concentration, by further solution dilution with specific viscosities hsp in the range of 0.2 to 1 were obtained which are suitable for the determination of intrinsic viscosities for the capillary viscometers, a total volume of about 20 ml solution was needed. the polymer was dissolved completely and left at laboratory temperature. then 15 ml of the homogenous solution was injected inside the capillary and diluted to different concentrations by adding a certain amount of water to the capillary as shown in figure 1. fig. 1, schott ubbelohde capillary viscometer then the capillary inserted in the water bath type messgeraetewerk lauda, germany, with double thermostat type (d-60-s) has been set at temperature of (25°c) as shown in figure 2. fig. 2, water bath results and discussion the measurements of the intrinsic viscosity carried out for the samples (1, 3, 10, 20, 35 kg/mol) that obtained from physical chemistry institute at temperature 25 °c shown in figure 3. fig. 3, reduced viscosity versus specific viscosity for peo in water at 25°c fig. 3 shows that the polyethylene oxide (peo) behaves as neutral polymer in water. neutral polymers have the property that the reduced viscosity increases with increasing of the specific viscosity and polymer concentration, because the structure of peo may not contain ionic groups [45]. otherwise if the polymer contains e.g. a carboxyl groups the reduced viscosity would decrease with increasing the specific viscosity and concentration of the polymer: in dilute solution the effective electrostatic repulsion extends the polymer coil, while in more concentrated solution the electric charge of the chain are shielded by counter ions [46]. the measurements were done at 30 ºc in water to check the value of high molecular weights samples of polyethylene oxide obtained from sigma aldirch company because only a very broad molecular weight range was given in the specification. at 30 ºc reliable values of k and a can be taken from the literature [47]. the values of intrinsic viscosities obtained by capillary measurements using schott ubbelohde capillary viscometer size as shown in figure 4. 0 10 20 30 40 50 60 70 80 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 spesific viscosity r e d u c e d v is c o si ty ( g /m l) peo 1 kg/mol peo 3 kg/mol peo 10 kg/mol peo 20 kg/mol peo 35 kg/mol structure rheology of polyethylene oxide solution 28 ijcpe vol.15 no.1 (march 2014) -available online at: www.iasj.net fig. 4, reduced viscosity versus specific viscosity for peo in water at 30 °c the results of the measurement of the capillary viscometer at 30 ˚c give values of molecular weights which are approximately the same that were obtained from sigma aldirch, company as shown in table below: table 1, the values of the calculated molecular weight and intrinsic viscosity of peo samples were obtained from sigma aldrich at 30 ºc obtained molecular weight (kg/mol) intrinsic viscosity [η (ml/g) calculated molecular weight (kg/mol) linear peo 100 98.6 99 linear peo 300 274.1 370 linear peo 1000 622.8 1100 linear peo 4000 1273.2 4600 linear peo 8000 2353.3 8000* * all the measurements at 30 ºc show results close to what obtained from sigma aldirch company expect these for 8000 kg/mol sample which had a wide range of error, so it used with this error because the other results were reasonable. the measurements of the intrinsic viscosity carried out for the measured values of the samples that obtained from sigma aldirch, company at 25 °c as shown in figure 5. fig. 5, reduced viscosity versus specific viscosity for peo in water at 25 °c figure 5 shows that polyethylene oxide (peo) with high molecular weight also behaves as a neutral polymer in water. the reduced viscosity is a linear function of specific viscosity as for the concentration where it increases with increasing the specific viscosity of the polymer, while for 8000 kg/mol molecular weight the reduced viscosity shows a non-linear increasing with the specific viscosity. this special behavior for the highest molecular weight sample is due to aggregation effects or shear thinning which was observed in measurements with the rotational viscometer. for the branched polyethylene oxide the measured values are shown in figure 6. fig. 6, reduced viscosity versus specific viscosity for branched peo in water at 25 °c figure 6 for the branched polyethylene oxide shows the same influence for reduced viscosity with the specific 0 500 1000 1500 2000 2500 3000 0 0.2 0.4 0.6 0.8 1 1.2 specific viscosity r e d u c e d v is c o s it y ( g /m l) peo 99 kg/mol peo 370 kg/mol peo 1100 kg/mol peo 4600 kg/mol peo 8000 kg/mol 0 500 1000 1500 2000 2500 3000 3500 0 0.5 1 1.5 spesific viscosity r e d u c e d v is c o s it y ( g /m l) peo 99 kg/mol peo 370 kg/mol peo 1100 kg/mol peo 4600 kg/mol peo 8000 kg/mol 0 5 10 15 20 25 30 35 40 0 0.2 0.4 0.6 0.8 specific viscosity r e d u c e d v is c o s it y ( m l/ g ) branched peo 0.55 kg/mol branched peo 40 kg/mol talib omer kashmola and estabraq saad kamil -available online at: www.iasj.net ijcpe vol.15 no.1 (march 2014) 29 viscosity where it increases with increasing the concentration as the linear polyethylene oxide. by using eq. 3, and reduced viscosity equal to c sp , from figures 3 to 6 the relation of reduced viscosity against specific viscosity, usually gives a straight line, the slop of this line is equal to  2k and the intercept is equal to [η , so that uggin's constant kcan be determined from the slope, the values of intrinsic viscosity shown in table 2. table 2, intrinsic viscosity of peo solution at 25ºc molecular weight (kg/mol) intrinsic viscosity (ml/g) linear peo 1 4.1 linear peo 3 17.4 linear peo 10 25.8 linear peo 20 36.8 linear peo 35 53.3 linear peo 99 88.9 linear peo 370 303.5 linear peo 11*10 2 539.1 linear peo 46*10 2 1290.4 linear peo 8*10 3 1410.4 branch peo 0.55 3.8 branch peo 40 27.5 figures from 3 to 6 show that the hydrodynamic volume which proportional to   of peo in water increase with increasing the molecular weight for both linear and branched polyethylene oxide. the branched samples show a mach smaller intrinsic viscosity than the linear samples which close to them molecular weight. this effect is explained by the decrease of hydrodynamic volume with increase of branching. by using equation,   akm a plot of the log  versus log mwt for peo in water at 25°c usually gives a straight line, the intercept of this tine is equal to k and the slope is equal to ''a'' as shown in figure 7. fig. 7, log (molecular weight) versus log (intrinsic viscosity) for different peo in water at 25 °c table 3, huggin's constant and mark houwink parameter of peo in water at 25 ºc molecular weight (kg/mol) huggin's constant (k' ) k (ml/g) a linear peo 1 0.179 0 .0 0 6 8 0 .6 6 7 linear peo 3 0.335 linear peo 10 0.513 linear peo 20 0.683 linear peo 35 0.289 linear peo 99 0.577 linear peo 370 0.284 linear peo 1100 1.016 linear peo 4600 0.757 linear peo 8000 1.477 branch peo 0.55 1.174 branch peo 40 0.67 conclusion for dilute solution of polyethylene oxide in water the reduced viscosity increases with increasing concentration. the peo behaves as neutral polymer, and intrinsic viscosity of polyethylene oxide in water increases with increasing the molecular weight. -2 -1 0 1 2 3 4 0 1 2 3 4 5 6 7 8 log (mwt) (g/mol) lo g ( in tr in s ic v is c o s it y ) (m l/ g ) linear peo branched peo structure rheology of polyethylene oxide solution 30 ijcpe vol.15 no.1 (march 2014) -available online at: www.iasj.net k and a (mark-houwink constants) were determined for polyethylene oxide in water at temperature 25 °c also for high molecular weight up to 8000 kg/mol, which has not been mentioned in the literature so far. references 1"polyethylene oxide", http://www.refrence:table.com :"description and solubilityp.htm". 2"polyethylene oxide", encyclopedia of polymer science and technology the free incyclopedia.htm, http://www.en.wikipedia.org. 3"poly (ethylene glycol) and poly (ethylene oxide)", http://www.sigma-aldrich/co.com. 4bailey jr fe, koleske jv. poly (ethylene oxide), new york: academic press; 1976. 5finch ca, editor, chemistry and technology of water soluble polymers. new york: prenum press; 1983. 6j. h. sung, d. c. lee, and h. j. park, "conformational characteristics of poly (ethylene oxide) (peo) in methanol" polymer, vol. 48, 4205-4212, may 2007. 7y. chen, journal of polymer science: part a: polymer chemistry, vol. 42, 2263–2271, 2004. 8p.j. carreau, polym. eng. sci., society of plastics engineers, vol. 45:1385–1394, 2005. 9y. fang, p.j. carreau, and p.g. lafleur, polym. eng. sci., 43, 1391, 2003. 10 i.w. hamley, angew. chem. int. ed., vol. 42, 1682, 2003. 11 kharchenko, s. b.; kannan, r. m. macromolecules, vol. 36, 407– 415, 2003. 12 furukawa, t.; ishizu, k. macromolecules, vol. 36, 434–439, 2003. 13 i.w. hamley, nanotechnology, vol 14, r39, 2003. 14 s. hou, d. taton, m. saule, j. logan, e. chaikof, y. gnanou, polymer, vol. 44, 5067, 2003. 15 macromol, "multiarm star polymer (peo)", chem. phys., vol. 211, 35–44, 2010. 16 lee jh, lee hb, "andrade jd blood compatibility of polyethylene oxide surfaces". prog polym sci., vol. 20:1043–1079, 1995. 17 allen c, maysinger d, "eisenberg a nano-engineering block copolymer aggregates for drug delivery". colloids surf b vol. 16:3–27, 1999. 18 villain fl, parel jm, lee w, simon g injectable polyethylene oxide gel implant and method for production. wo pat. 006883, 1996. 19 dormidontova ee, "role of competitive peo–water and water– water hydrogen bonding in aqueous solution peo behaviour". macromolecules, vol. 35:987– 1001, 2002. 20 daoust h, st cyr d "microcalorimetric study of poly (ethylene oxide) in water and in water–ethanol mixed solvent". macromolecules, vol. 17:596–601, 1984. 21 gray fm, armand m in: osaka t, datta m (eds) new trends in electrochemical technology: energy storage systems for electronics, gordon and breach, new york, pp 351– 406, 2000. 22 wright pv, polymer electrolytes—the early days. electrochim acta, vol. 43(10– 11):1137–1143, 1998. 23 vijayalakshmi sp, chakraborty j, madras g, "thermal and microwave-assisted oxidative degradation of poly (ethylene oxide)". j appl polym sci, vol. 96:2090–2096, 2005. http://www.refrence:table.com http://www.en.wikipedia.org/ http://www.sigma-aldrich/co.com talib omer kashmola and estabraq saad kamil -available online at: www.iasj.net ijcpe vol.15 no.1 (march 2014) 31 24 morlat s, gardette jl, phototransformation of water soluble polymers. part ii: photooxidation of poly (ethylene oxide) in aqueous solution. polymer, vol. 44:7891–7897, 2003. 25 hassouna f, morlat-thérias s, mailhot g, gardette jl (2007) influence of water on the photodegradation of poly(ethylene oxide). polym degrad stab, vol. 92:2042–2050, 2007. 26 pritchard nj, hughes de, peacocke ar, "the ultrasonic degradation of biological macromolecules under conditions", 1966. 27 kanwal f, pethrick ra, "ultrasonic degradation studies of poly (ethylene oxide), poly (ethylene adipate) and poly (dimethylsiloxane)". polym degrad stab, vol. 84:1–6, 2004. 28 madras g, mccoy bj, "molecular-weight distribution kinetics for ultrasonic reactions of polymers". aiche j, vol. 47: 2341– 2348, 2001. 29 hammouda b, ho dl, kline s, "insight into clustering in poly (ethylene oxide) solutions", macromolecules, vol. 37:6932– 6937, 2004. 30 polik wf, burchard w, "static light scattering from aqueous poly (ethylene oxide) solutions in the temperature range 20–90◦c", macromolecules, vol. 16:978–982, 1983. 31 duval m, "monitoring of cluster formation and elimination in peo solutions". macromolecules, vol. 33:7862–7867, 2000. 32 ghosh, p., and haltu, p.p.,'' fundamental of polymer science, molecular weights of polymers'', http://nsdl.niscair.in/bitstream/1234 56789/406/2/molecular+weights +of+polymers.pdf, 2006. 33 flory, p.j., and t. g. fox, jr, ''treatment of intrinsic viscosites'', j. am, chem, soc., vol. 73, pp. 1904-1908, 1951. 34 ''macrolab experiment dilute solution viscosmetry, molecular weight determination by dilute solution viscosity measurements'', http://www.pslc.ws/macrog/lab/dsv h.htm. 35 cowie, j.m.g., ''polymer chemistry and polymer science of modern materials'', new york, 1973. 36 ''intrinsic viscosity'', http://www.google.it/search?ht=ena ndq=intrinsic +viscosityandbthg.=google+search . 37 ''determination of molecular weight of polymers'', http://74.125.113.132/sarch?q=cach e:pkz6w_zqfkqj:www.polymer.hah acett, 2009. 38 rodriguez, f., ''principles of polymer systems'', secand edition, mc graw –hill book company, 1985. 39 gowariker, v.r., n.v. viswanathan and j. sreedhar, "polymer science", john wiley and sons, new york, 1987. 40 slaiman, i.n., ''effectiveness of polyisobutylene of drag reducing agent in turbulent pipe flow'', ph.d thesis, al-nahrain university, baghdad, 2000. 41 taofeaq, h. m., ''effect of molecular weight on turbulent drag reduction with polyisobutylene additives'', m.sc thesis, al-nahrain university, baghdad, 2006. 42 mohamed, h.j., ''study of drag reduction in turbulent flow using high molecular weight polymers'', m.sc thesis, al-nahrain university, baghdad, 2006. 43 atshan, a. a., ''turbulent drag reduction of polyacrylamide and http://nsdl.niscair.in/bitstream/123456789/406/2/molecular+weights http://nsdl.niscair.in/bitstream/123456789/406/2/molecular+weights http://www.pslc.ws/macrog/lab/dsvh.htm http://www.pslc.ws/macrog/lab/dsvh.htm http://www.google.it/search?ht=en&q=intrinsic http://www.google.it/search?ht=en&q=intrinsic http://74.125.113.132/ structure rheology of polyethylene oxide solution 32 ijcpe vol.15 no.1 (march 2014) -available online at: www.iasj.net xanthan gum, experimental and theoretical investigation, m.sc thesis, alnahrain university, baghdad, 2008. 44 abdul jabbar , m. f., '' the influence of mechanical effects on degradation of drag reducing agents'', m.sc thesis, al-nahrain university, baghdad, 2008. 45lebedeva, o. v., ''technology of pressure –sensitive adhesives and product'', crc press, chapter four, 2009. 46 zeynali, m. e., a. rabii, and h. baharvand, ''synthesis of partially hydrolyzed polyacrylamide and investigation of solution properties (viscosity behaviour)'', iranian polymer journal, vol. 13, no.6, pp. 479484, 2004. 47r. byron bird, dynamics of polymeric liquids, vol. 1, fluid mechanics, 112-114, 1948. ijcpe vol.11 no.1 (march 2010) 21 iraqi journal of chemical and petroleum engineering vol.11 no.1 (march 2010) 21-27 issn: 1997-4884 diffusion kinetics of furfural adsorption onto activated carbon abbas h. sulaymon * , kawther w. alhayali * and ammar waadallah ahmed ** * environmental engineering department college of engineering university of baghdad – iraq ** biochemical engineering department – college of khawarizmi– university of baghdad – iraq abstract a range of batch experiments were carried out for the estimation of the key process parameters in adsorption of furfural from aqueous solution onto activated carbon in fixed-bed adsorber. a batch absorber model has been used to determine the external mass transfer coefficient (kf) which equal to 6.24*10-5 m/s and diffusion coefficient (dp) which equal to 9.875*10-10 m2/s for the furfural system. the langmuir model gave the best fit for the data at constant temperature (30oc). the pore diffusion mathematical model using nonlinear isotherm provides a good description of the adsorption of furfural onto activated carbon. keywords: adsorption, batch adsorber, furfural, isotherm, pore diffusion, modelling introduction adsorption techniques are widely used in the field of removing small quantities of pollutant present in large volume of fluid, which can be carried out in batch wise or continuous manner of operation [1, 2, 3, and 4]. the design of single scale adsorption plants is still based on expensive experimental pilot-plant studies because a thorough understanding of process is lacking. the effective application of activated carbon adsorption requires a predictive model to facilitate the development of systematic design procedure [5, 6]. the key parameters for design of the adsorption system such as isotherm constants and mass transfer coefficients are the process parameters that are used for modeling the system for predicting the quality of effluent under a wide range of operating conditions [7]. the rates of adsorption of solute from aqueous and other liquid solutions by porous solid in batch-type system are greatly influenced by the mass transfer resistance outside the particles, diffusion resistance inside the particles, geometry of the pores, type of adsorption isotherm, operating conditions such as initial concentration, ph, temperature, phase ratio, agitation speed and vessels geometry [8, 9]. dedrick and beckmann [10], represented a mathematical model described the amount adsorbed as a function of time for diffusion into sphere particles with a constant effective diffusivity. digiano [11], developed adsorption model included the effect of mass transfer both at the external carbonsolution interface and with the carbon pore structure. suzuki and kawazoa [12], developed a simple technique to determine the intraparticle diffusivities of adsorbents from concentration change in an agitated tank. pore diffusion and rectangular isotherm are assumed to derive the theoretical solution. ivars [13], solved numerically a mathematical model for finite bath adsorption of nonlinear isotherm described either by langmuir or fruendlich type equations. the transport mechanism in the particles is assumed to be pore diffusion, solid diffusion or a combined. the effect of film resistance is included. the objective of the present research is to estimate the equilibrium and kinetic data of the adsorption of furfural (fu) from aqueous solution onto activated carbon. these data are required to solve the mathematical model which includes axial dispersion, film mass transfer, pore diffusion resistance and non-linear isotherms of the university of baghdad college of engineering iraqi journal of chemical and petroleum engineering diffusion kinetics of furfural adsorption onto activated carbon 22 ijcpe vol.11 no.1 (march 2010) adsorption process in fixed-bed adsorber [7]. for accurate estimation of external mass transfer coefficient, and intraparticle diffusion coefficients for furfural, the experimental results will be compared with that simulated by the numerical solution of the batch adsorber model. modeling of a multicomponent batch adsorber for batch adsorber, the mathematical model with pore diffusion model (8, 14) is:  mass balance in fluid-bulk phase:   03 ,   prrpbf pp ab l cck r w dt dc v  (1) where vl = volume of fluid in the batch adsorber wa = mass of activated carbon in the batch adsorber  mass balance inside particle phase:                r c r rr d dt dq t c p ppp p p 2 2 1  (2)  initial and boundary conditions are: in case of applying langmuir isotherm model: p pm bc bcq q   1 (6) where: cb and cp are the solute concentration in the fluid-bulk and particle phase, respectively. mass transfer to particles suspended in a liquid in turbulent flow, particularly in agitated vessels, has been studied by several investigators [15, 16, 17, 18]. however, these studies have shown a variety of results and have not predicted reliable correlations that are universally applicable [19]. the inability to develop satisfactory correlations may stem from the fact that the flow fields around particles moving freely in the liquid are not only a function of the reactor and impeller geometries and power input, but also the particle shape and particle diameter distribution (20) sano et al. [21] incorporated the effect of particle shape, by introducing the term φc, the garman's surface factor, and developed the following correlation:        3 1 4 1 re4.02 scsh mc (7) alexander and zayas [20] developed the following equations for the particle size fractions with a sauter mean diameter less than 923 μm (20/25 size). 3 1 4 1 re41.0 scsh m , for 10 2 < rem < 10 5 (8) 3 1 4 1 re37.02 scsh m , for rem > 10 5 (9) for particles larger than 923 μm: 3 1 8 1 re60.1 scsh m , for 10 2 < rem < 10 5 (10) 3 1 8 1 re58.12 scsh m , for rem > 10 5 (11) alexander and zayas found that the external mass transfer coefficient can be expected to vary with the three-fourth power of impeller speed, for particles in the 300 to 900 μm range. for larger particles, kf is shown to be proportional to dp -0.5 , this agrees well with the data and intuitive reasoning provided by harriot and vermeulen [22]. the external mass transfer coefficient for the solute adsorbed at certain particle size and optimum agitation speed, can be obtained by the analytical solution for equation 1, where at t = 0, cp,r=rp = 0 and cb = co , hence:          o t a lpp f c c tw vr k ln 3  (12) where co, ct are the solute concentration at time zero and time (t) and obtained from the typical concentration decay curve (20). experimental concentration-time data are compared to predicted concentration-time profiles for the above batch adsorber model and the best statistical description, used to determine the intraparticle pore diffusion coefficient. if diffusion into particle is controlled by the surface concentration gradient, equation 2 is replaced by:              r q r rr d t q s 2 2 1 (13) with the same above procedure the surface coefficient can be obtained. the bulk-fluid phase and particle equations for the batch adsorber model are first descried using the finite element (fe) and the orthogonal collocation (oc) methods, respectively. the resulting ode system is solved using an existing ode solver provided by matlab v-6.5. experimental work the granulated activated carbon (gac) used in the experiments was supplied by unicarbon, italian. its physical properties are supplied by the company and listed in table 1. the gac was sieved into 28/32 mesh with geometric mean diameter of 0.5mm.the gac was boiled, washed abbas h. sulaymon, kawther w. alhayali and ammar waadallah ahmed ijcpe vol.11 no.1 (march 2010) 23 three times in distilled water, and dried at 110 °c for 24 h, before being used as adsorbent. the aqueous solution of furfural was prepared using reagent grade. the properties of furfural are listed in table 2. equilibrium isotherm experiment batch studies were used to obtain the majority of equilibrium data. solution was prepared containing the desired solute concentration. the experiment was adjusted at the initial ph of 8.1 for furfural with 0.01 mol/l naoh and 0.01 mol/l hcl. 100 ml portions of the solution were placed in bottles of 250 ml in volume, containing accurately different weighted amount of activated carbon. the bottles were then placed on a shaker (type b. baun, karlkolb) and agitated continuously for 30 hours at 30 °c. the equilibrium concentrations were measured by means of uv-spectrophotometer. at this point the concentration is in equilibrium. the adsorbed amount is then calculated by the following equation:   a eol e w ccv q   (14) the adsorption isotherms were obtained by plotting the weight of the solute adsorbed per unit weight of activated carbon (qe) against the equilibrium concentration of the solute in the solution (ce) (23). kinetic experiments the external mass transfer coefficient kf and the intraparticle diffusion coefficients were obtained by using a well stirred batch contactor. in this method, a known amount of adsorbent is added to a constant volume of solution. the rate of adsorption of solute was measured by monitoring the solute concentration with time, using uv spectrophotometer. a 2 liter pyrex beaker was used fitted with a variable speed (0 – 1000 rpm) electrical mixer with 4-blade stainless steel impeller (janke and kunkel, ika-werk). the beaker was filled with 1.0 liter of known concentration solution and the agitation started before adding the activated carbon. at time zero, the accurate weight of activated carbon was added. samples were taken every 10 minute during the experiment for analysis and these samples were returned back to the solution to achieve constant volume. the necessary dosage of activated carbon to reach an equilibrium concentration of c/co=0.05 was calculated from isotherm equation and balance equation for furfural as follow (in case of langmuir model):                  e em eol e eol a bc bcq ccv q ccv w 1 (15) the optimum agitation speed was obtained by repeating the experiments for furfural with variable speed (600, 700, 800, 900 and 1000 rpm). the optimum agitation speed is the speed needed to achieve ce/co = 0.05. the batch experiments were achieved for furfural at constant temperature (30 °c). results and discussion adsorption isotherm the adsorption isotherm for furfural onto activated carbon of size 0.5 mm at 30 o c is shown in figures 1. furfural isotherm ,co,fu=0.2 kg/m 3 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0 0.05 0.1 0.15 0.2 ce (kg/m 3 ) q e ( k g /k g ) theoretical (langmuir model) experimental figure (1) adsorption isotherm for furfural onto activated carbon at 303 k the entire adsorption isotherm displays a nonlinear dependence on the equilibrium concentration. the adsorption data for furfural fitted by langmuir model (3), freundlich model (3), radke-prausnitz model (24), dubinin–radushkevich model (25), reddlich-peterson model (3), and combination of langmuir-freundlich (26). the parameters for each model were obtained from non-linear statistical fit of the equation to the experimental data. all parameters with correlation coefficients are summarized in table 3. it is clear from figure 1 and table 3 that:  the equilibrium isotherm for furfural is of favourable type, for being somewhat convex upward and relatively high activated carbon loading were obtained at low concentration of solute in water.  the langmuir model gives the best fit of the experimental data of furfural.  the low adsorption capacity of furfural may be explained by its higher solubility, low molecular weight and low octanol-water coefficient.  furfural is a polar solvent and activated carbon is generally regarded to favor the adsorption of nondiffusion kinetics of furfural adsorption onto activated carbon 24 ijcpe vol.11 no.1 (march 2010) polar compounds rather than polar compounds, since pure carbon surface is considered to be non-polar, but in actual practice, some carbon-oxygen complexes are present which render the surface slightly polar (27). estimation of intraparticle diffusion coefficient the intraparticle diffusion coefficient for fu can be estimated by matching the experimental concentration decay curves at optimum agitation speed with the predicting concentration decay curve, which can be generated by the numerical solution of the batch adsorber model. first of all it must be tried to use the pore diffusion model for batch adsorber. if no matching between experimental and predicted results then the surface diffusion model must be used. the estimation of intraparticle diffusion coefficient needs the following steps: 1. estimation of optimum agitation speed for batch adsorber to reach the needed equilibrium concentration. 2. estimation of mass transfer coefficient in batch process for furfural at optimum agitation speed. 3. numerical solution of batch adsorber model to obtain the intraparticle diffusion coefficient for furfural. optimum agitation speed the typical concentration decay curves of solute in batch experiments were carried on for furfural at different agitation speeds. the amounts of activated carbon used for furfural was calculated for final equilibrium related concentration of ce/co = 0.05. using the langmuir equation with mass balance in one liter of solution (equation 12), the dose of activated carbon for furfural is 3.263×10 -3 kg. the agitation speeds (600, 700, 800, 900, 1000 rpm) were used as shown in figures 2. furfural system ,co,fu=0.2 kg/m 3 0.0 0.2 0.4 0.6 0.8 1.0 1.2 0 50 100 150 200 250 time (min.) c /c o 600 rpm 700 rpm 800 rpm 900 rpm 1000 rpm figure (2) concentration-time decay curves for furfural adsorption onto activated carbon in batch process at different agitation speed the optimum agitation speed needed to achieve ce/co = 0.05 was 900 rpm. it is clear that, if the speed is above 900 rpm, the equilibrium relative concentration is less than 0.05; this is due to pulverization of activated carbon at high speed of agitation. external mass transfer coefficient in batch adsorber the external mass transfer coefficient in batch adsorber was computed from initial rate data, i.e. from the concentration decay curve of optimum speed and using equation 9. for accurate estimation of kf, samples were taken after 2, 4 and 6 minutes and analyzed immediately. the average calculated values kf for furfural is 0.624×10 -4 m /s intraparticle diffusion coefficient intraparticle diffusion coefficients for furfural was obtained from the numerical solution of equations 1 and 2 with the appropriate initial and boundary condition that describe the film and intraparticle transport mechanisms in batch-wise experiments, using the external mass transfer coefficient estimated in previous section. the pore diffusion coefficient was derived from the typical concentration decay curve for furfural by an iterative search technique predicted on the minimization of the difference between experimental and predicted data from pore diffusion model as shown in figure 3. furfural system ,dp=9.875*10 -10 m 2 /s , kf=6.24*10 -5 m/s 0.0 0.2 0.4 0.6 0.8 1.0 1.2 0 50 100 150 200 250 time (min) c /c o experimental theoretical figure (3) comparison of the measured concentrationtime datawith that predicted by pore diffusion model in batch adsorber for furfural. it is clear from figure 3; there was a good matching between experimental and predicted data by using pore diffusion model. the pore diffusion coefficient for furfural was 9.875×10 10 m 2 /s with a correlation coefficient of 0.9921. it is clear from above data that there was a good matching between experimental and predicted data in batch experiment by using pore diffusion model for furfural. hence the transfer of furfural within the activated carbon is controlled by pore diffusion. abbas h. sulaymon, kawther w. alhayali and ammar waadallah ahmed ijcpe vol.11 no.1 (march 2010) 25 the estimated values of isotherm constants, external mass transfer coefficients kf, and pore diffusion coefficients dp, were used to solve the mathematical model which describes the adsorption process in fixed-bed adsorber [7]. conclusions the concentration decay curves obtained during batch kinetic studies on the adsorption of furfural on activated carbon were simulated by a combined external film transfer-pore diffusion model. it is clear from above data that there was a good matching between experimental and predicted data in batch experiment by using pore diffusion model for furfural. hence the transfer of furfural within the activated carbon is controlled by pore diffusion. the estimated values of isotherm constants, external mass transfer coefficients kf, and pore diffusion coefficients dp, were used to solve the mathematical model which describes the adsorption process in fixed-bed adsorber [7]. nomenclature symbols ar reddlich-peterson model parameter br reddlich-peterson model parameter b langmuir constant, m 3 /kg c concentration in fluid, kg/m 3 co initial concentration, kg/m 3 dp pore diffusion coefficient, m 2 /s dm molecular diffusion coefficient, m 2 /s ds surface diffusion coefficient, m 2 /s dp particle diameter, m fu furfural frp radk-prausnitz model parameter g gravitational force (=9.81 m/s 2 ) k freundlich model parameter kow partition coefficient for actanol-water, krp radk-prausnitz model parameter symbols kf fluid to particle mass transfer coefficient, m/s mr reddlich-peterson model parameter nrp radk-prausnitz model parameter n freundlich model parameter p agitation power per unit mass of fluid, w/kg qdr maximum adsorption capacity in the micropore volume (kmole/kg) q internal concentration of solute in particle , kg/kg qm adsorption equilibrium constant defined by langmuir equation, kg./kg re reynolds number         w pw vd   , rem modified reynolds number         3 4 c p pd  , rp radius of particle, m r radial direction, m s surface area, m 2 sc schmidt number         imw w d ,   , sh sherwood number         im pif d dk , , , sw specific surface area, m 2 /kg t time, s vl volume of solution, m 3 wa mass of activated carbon, kg diffusion kinetics of furfural adsorption onto activated carbon 26 ijcpe vol.11 no.1 (march 2010) greek symbols εp porosity of adsorbent, β characteristic parameter related to adsorption energy  polanyi adsorption potential μc kinematics viscosity, m 2 /s μw viscosity of water (=0.8937×10 -3 pa.s) ρp particle density, kg/m 3 ρs solid density, kg/m 3 ρw density of water, kg/m 3 φc carman's surface factor         gmws ds 6 subscript b bulk fluid phase e equilibrium fu furfural l liquid phase o initial p particle phase references 1juang, r.; wu, f. and tseng, r. adsorption isotherms of phenolic compounds from aqueous solutions onto activated carbon fibers. j. chem. eng. data, 1996, 41, 487-492. 2gupta, a.; nanoti, o. and goswami, a. n. the removal of furfural from water by adsorption with polymeric resin. sep. sci. and technol. 2001, 36 (13), pp 2835-2844. 3lucas, s. and cocero, m. j. adsorption isotherms for ethylacetate and furfural on activated carbon from supercritical carbon dioxide. fluid phase equilibria, 2004, 219, pp 171-179. 4rao, c. s. environmental pollution control engineering. new age international 2 nd ed. 2006. 5fritz, w.; merk, w. and schlunder, e. u. competitive adsorption of two dissolved organic onto activated carbon, i-adsorption equilibria. chem. eng. sci. 1981, 36, pp 721-730. 6crittenden, j. c.; hand, d. w. and kimberly, a. h. manual of adsorption design software for windows (addesigns), 1999. 7sulaymon, a. h. and ahmed k. w. competitive adsorption of furfural and phenolic compounds onto activated carbon in fixed bed column. environ. sci. technol. 2008, 42, 392–397. 8leyva, r. r. and geankoplis, c. j. model simulation and analysis of surface diffusion of liquids in porous solids. chem. eng. sci. 1985, 40 (5), pp 799807. 9babu, b. v. and ramakrishna, v. dominant design variables and modeling parameters for adsorption in batch studies. chem. conf., mumbai.2004. 10dedrick, r. l. and beckmann, r. b. kinetics of adsorption by activated carbon from dilute aqueous solution, physical adsorption processes and principles. aiche j., symposium series. 1967, 74 (63), p 68. 11digiano, f. a. a simplified competitive equilibrium adsorption model. chem. eng. sci. 1978, 33, pp 1667-1673. 12-suzuki, m. and kawazoa, k. batch measurement of adsorption rate in an agitated tank. j. chem. eng. jap.1974, 7 (5), pp 346-350. 13ivars, n. analysis of some adsorption experiments with activated carbon. chem. eng. sci. 1976, 31, pp 1029-1035. 14ping l. and guohua, x. adsorption and desorption of phenol on activated carbon fibers in fixed bed (ii). separation science and technology. 2001, 36 (10), pp 2147-2163. 15brain, p. l. t.; hales, g. b. and sherwood, t. k. transport of heat and mass between liquids and spherical particles in an agitated tank. aiche j.1969, 15, pp 727-732. 16boon-long, s.; laguerie, c. and couderc, j. p. mass transfer from suspended solids to a liquid in agitated vessels. chem. eng. sci.1978, 33, pp 813-819. 17calderbank, p. h. and moo-young, m. b. the continuous phase heat and mass transfer properties of dispersion. chem. eng. sci.1961, 16, pp 39-54. 18neinow, a. w. and miles, d. the effect of impeller/tank configuration on fluid particle mass transfer. the chem. eng. j.1978, 15, pp 13-24. 19mathews, a. p. and weber, w. j. effect of external mass transfer and intraparticle diffusion on adsorption in slurry reactors. aiche j., symposium series. 1977, 73, pp 91-98. abbas h. sulaymon, kawther w. alhayali and ammar waadallah ahmed ijcpe vol.11 no.1 (march 2010) 27 20alexander, p. m. and zayas, i. particle size and shape affects on adsorption rate parameters. j. environmental engineering, 1989, 115 (1), feb., pp 41-55. 21sano, y., yamaguchi, n. and adachi, t. mass transfer coefficient for suspended particles in agitated vessels and bubble column. j. chem. eng. jap.1974, 7, pp 255-261. 22harriott, n. k. and vermeulen, t. mass transfer to particles suspended in agitated tanks, part i. aiche j. 1962, 8, pp 93-101. 23crittenden, j. c. and weber, i. r. predictive model for design of fixed-bed adsorbers, single component model verification. environmental engineering division, 1978, 104 (ee3), june, pp 433-443. 24radke, c. j. and prausnitz, j. m. adsorption of organic compounds from dilute aqueous solution on activated carbon. ind. eng. chem. fund. 1972, 11, pp 445-451. 25monneyron, p. and faur-brasqet, c. competitive adsorption of organic micropollutant in the aqueous phase onto activated carbon cloth. langmuir, 2002, 18, pp 5163-5168. 26sips, r. on the structure of a catalyst surface. j. chem. phys. 1984, 16, pp 490-495. 27al-bahrani, k. s. and martin, r. j. adsorption studies using gas-liquid chromatography. ieffect of molecular structure. water res. 1976, 10, pp 731-736. كوثر وعداهلل و عمار وعد اهلل, عباس حميد سليمون تى إجشاء تجبسة يٍ انُوع انًُطً إلٌجبد انقٍى انالصيخ فً تصًٍى عًود رو انحشوح انثبثتخ اليذصبص انفوسفوسال تى اقتشاح يودٌم سٌبضً نًُظويخ االيذصبص يٍ انُوع انًُطً الحتسبة يعبيم اَتقبل انكتهخ . ثواسطخ انكبسثوٌ انًُشط تجٍٍ أٌ استخذاو يودٌم الَكًبٌش هو األَست فً وصف . نهفوسفوسال فً انكبسثوٌ انًُشط (dp) و يعبيم االَتشبس (kf)انخبسجً 10*6.24 ٌسبوي (kf)ي يعبيم اَتقبل انكتهخ انخبسج يئوي حٍث وجذ اٌ 30 عًهٍخ االيذصبص عُذ دسجخ حشاسح ثبثتخ -5 m/s و 10*9.875 ٌسبوي(dp)يعبيم االَتشبس نهفوسفوسال فً انكبسثوٌ انًُشط -10 m 2 /s ، واٌ استخذاو انًودٌم انشٌبضً نًُظويخ " صحٍحب" االيذصبص يٍ انُوع انًُطً وانزي ٌعتًذ عهى وصف االَتشبس داخم انكبسثوٌ انًُشط يٍ انُوع انفجوي ٌعطً وصفب . نعًهٍخ ايذصبص انفوسفوسال عهى انكبسثوٌ انًُشط" و دقٍقب available online at https://ijcpe.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.19 no.1 (march 2018) 13 – 19 issn: 1997-4884 corresponding authors: ammar s. abbas, email: ammarabbas@coeng.uobaghdad.edu.iq, marwa g. saber, email: eng.marwa1991@yahoo.com iraqi journal of chemical and petroleum engineering kinetics of thermal pyrolysis of high-density polyethylene ammar s. abbas a and marwa g. saber a chemical engineering department – college of engineering – university of baghdad(iraq) abstract thermal pyrolysis kinetics of virgin high-density polyethylene (hdpe) was investigated. thermal pyrolysis of hdpe was performed using a thermogravimetric analyzer in nitrogen atmosphere under non-isothermal conditions at different heating rates 4, 7, 10 °c/min. first-order decomposition reaction was assumed, and for the kinetic analysis kissinger-akahira-sunose(kas), flynnwall-ozawa(fwo) and coats and redfern(cr) method were used. the obtained values of average activation energy by the kas and fwo methods were equal to137.43 and 141.52 kj/mol respectively, these values were considered in good agreement, where the average activation energy value obtained by cr equation methods was slightly different which equal to 153.16 kj/mol. keywords: thermogravimetric, kinetic, thermal degradation, polyethylene 1introduction production of plastic has increased by an average of 10% every year on a global basis since 1950[1,2]. on other hand the duration life of plastic is very small. almost 40% of plastic consumed has duration of life smaller than one month. the service life of plastic products ranges from 1 to 35 years depending on the area of application [3]. so the increase in plastic wastes because of the frequent use of such materials was expected result. at the same time, not all of these materials were recycled or treated therefore the disposal of these wastes has become a major environment concern [4]. as a conventional plastic material, polyethylene (pe), with its two types; high density polyethylene (hdpe) and low density polyethylene (ldpe) [5], continues to play an essential part in the commodities because of its resistance to microbial or enzymatic degradation. in addition is a major component of plastic waste from domestic refuse [6]. also polyethylene it is one-third of the global consumption of plastic [3]. the plastic wastes accumulation problems took a lot of attention because of the importance of the issue. many of the solutions presented one of them is the landfilling of plastic wastes but this is unhelpful method due to slow degradation rates of plastic (10 to 450 years), soil pollution by plastic additives, polluting ground water and decreasing the landfill region [1,4]. another solution is by using incineration method but it is costing and it has caused environmental problems since it generates several pollutants to the atmosphere. so to reduce the damages and environmental impact caused by plastic wastes materials, they must be recycled and recovered [7]. recycling is able to solve the problem of waste plastic. it divided into two categories to mechanical recycling (primary and secondary) and feedstock recycling or chemical recycling [8]. this method involves different techniques, including pyrolysis, hydrolysis, methanolysis, hydrogenation, and gasification [1]. pyrolysis method is the most beneficial among the chemical recycling methods [1]. pyrolysis is thermochemical decomposition of organic materials in the absence of oxygen. it can be carried out in the absence of catalyst which is called thermal cracking or thermolysis and catalytic pyrolysis in the presence of a catalyst [9]. pyrolysis has become very promising technology for treating the waste plastic since plastics have a high calorific value of more than 40 mj/kg which is similar to those of common liquid fuels such as kerosene, gasoline, diesel, etc. [7]. the pyrolysis products include a carbonized char (solid residues) and a volatile fraction. a portion of the volatile fraction can be condensed to give olefins, paraffins, isoparaffins, naphthenics, and aromatics, while the remaining is a non-condensable high calorific value gas [10]. thermal pyrolysis involves the degradation of the plastic materials by heating them to temperature between 350 to 900 °c in the absence of oxygen to make sure that no oxidation of the polymer takes place [9]. thermogravimetric analysis (tga) is the main gate to understand the pyrolysis. tga is a technique of thermal analysis which measure the rate of change in the weight and the amount of material as a function of temperature or time under controlled atmosphere such as nitrogen, air, or other gases [11]. tga is considered as an excellent mean for studying the kinetics of degradation [12]. a. s. abbas and m. g. saber / iraqi journal of chemical and petroleum engineering91,9 (2018) 93-99 41 there are various methods to calculate the isothermal or non-isothermal solid-state kinetic data from tga. in general the most common of them can be classified into two major types: model-fitting and model-free methods that are listed in table 1 [10, 13]. table 1. non-isothermal methods for studying solid-state kinetics [10,13] model-fitting model-free  differential  freeman-carroll  coats and redfern  kissinger  flynn-wall and ozawa  vyazovkin and aic  kissinger-akahira-sonuse in the model-fitting method, different reaction models are fitted to the experimental data then the best model selected when giving the best statistical fit from which the activation energy (𝐸a) and frequency factor (𝐴) are calculated. however, model-fitting methods were broadly applied due to their ability to calculate the kinetic parameters directly from the results of tga [13,14]. model-free methods or iso-conversional methods estimate the activation energy at specific extent of conversion without the need for assumed reaction model [15]. sometimes it is called multi-curve methods because these methods require more than one kinetic curve to perform the analysis and these methods need different heating rates to calculate the activation energy [14]. many researchers study the decomposition of different materials by applied the models of tga such as degradation of polycarbonate [16], degradation of synthesized optically active polyamides[17], decomposition of huadian oil shale [18], thermal decomposition of tea waste [19], pyrolysis and gasification kinetics of the two tropical biomass species[20], thermal stability behavior of coconut coir, banana pseudo stem, pineapple leaf, and sugarcane bagasse fibers [21]. shubbar [22] study the pyrolysis of ldpe and hdpe in closed system batch reactor and obtained the temperature range, from tga, for ldpe from 380 to 507°c, while, the temperature range for hdpe was found from 386.5 to 514°c. kayacan et al. [23] study the thermal decomposition kinetics of ldpe and hdpe at 5, 10, 20 and 50 k/min heating rates it was found that the kinetics of the degradation of the ldpe and hdpe for non-isothermal conditions can be considered as a first-order reaction and the activation energy for raw hdpe has been calculated between 401 and 470 kj/mol and for the waste hdpe was in the range of 396 to 493 kj/mol. the activation energy values have been found for raw ldpe between 324 and 497 kj/mol and 271 to 333 kj/mol for the waste ldpe. kumar et al. [1] study the tga has been used for the non-isothermal kinetic study of waste high-density polyethylene pyrolysis under nitrogen atmosphere at different heating rates 10, 20 and 40 °c/min. the activation energy values of waste hdpe have been calculated as 207.43, 268.22 and 473.05 kj/mol at 10, 20 and 40 °c/min heating respectively. abbas and mohamed [24][25] reported tga for highdensity polyethylene (hdpe) and low density polyethylene (ldpe) at the heating rate equal to 20 °c/min from surrounding temperature to 800 °c in order to know the range of effective temperature for pyrolysis. the decomposition of ldpe started at 349 °c and completed at 489 °c, whereas the hdpe decomposition started at 326 °c and completed at 495 °c. in the present work, the kinetics of the thermal degradation using tga of virgin hdpe was studied according to different models methods; kissinger akahira-sunose (kas), flynn-wall-ozawa (fwo) and coats and redfern (cr). the values of activation energy for waste hdpe have been obtained in non-isothermal condition assuming firstorder reaction kinetic at different heating rates. 2experimental 2.1. tga procedure the thermal decomposition behavior was studied by tga analyzer apparatus (type linseis sta pt-1000 tga) which shown in figure 1. twenty milligrams of the virgin hdpe were placed on the sample holder and pyrolyzed in nitrogen atmosphere in each experiment. pyrolysis was carried out at non-isothermal conditions with temperature range from room temperature to about 600 °c and the tga and differential gravimetric analysis (dtga) data were recorded at different heating rate (hr) (4, 7 and 10 °c/min.). the main physical properties of virgin hdpe pellets are shown in table 2. fig. 1. thermogravimetric tga analyzer a. s. abbas and m. g. saber / iraqi journal of chemical and petroleum engineering91,9 (2018) 93-99 41 table 2. virgin hdpe pellets physical properties property value average particle diameter, mm 3 density, g/cm 3 0.956 0.963 deflection temperature (at 0.46 mpa), °c 75 – 85 melting point, °c 130 – 135 melt flow index, g/10min 0.05 0.43 2.2. non-isothermal kinetic study using tga the non-isothermal kinetics for pyrolysis is usually written as follows: (1) where x is a conversion of hdpe, and is given by: (2) where w, wi, and wf, represent the instantaneous, initial, and final weights of the sample. the reaction rate constant k is expressed in terms of the arrhenius equation as: (3) and the function f(x) can be written as: (4) substituting eq. (3) and (4) into eq. (1) gives: (5) for a constant heating rate hr=dt/dt, eq. (5) can be rearranged to the following equation: (6) equation (6) represents the differential form of the nonisothermal rate law [14][26]. the thermal analysis methods start from the general differential kinetic eqs. (5) and (6) or the integral forms of them as follow. a. the kas method the kas method was based on the following equation: (7) where g( ) is the integral conversion function (reaction model) which is reported in the literature [27]. for constant conversion a plot of left side of the above equation against 1000/ at different heating rates is a straight line whose slope and intercept can evaluate the activation energy and pre-exponential factor, respectively [28]. b. the fwo method the fwo method is based on the following equation: (8) thus, for a constant conversion, a plot of natural logarithm of heating rates, ln(hr),versus 1000/ obtained from thermal curves recorded at different heating rates will be a straight line whose slope (−1.052( / )) from which the activation energy can be determined [14]. c. the cr method taking the logarithm of both sides of eq. (6) gives: (9) if n=1 (10) the above two equations (9 and 10) are the cr method the plot of left hand side of the above equations (9 and 10) on ( ) the y-axis versus 1/t. accordingly, the apparent activation energy ( ) and the apparent frequency factor (a) can be determined from the slope and intercept of the regression line, respectively [29,30]. 3results and discussion 3.1. tga and dtga of hdpe the thermal stability of the polymeric materials plays a crucial role in determining the limit of their working temperature and the environmental conditions for uses, which are related to their thermal decomposition temperature and decomposition rate. tga applied in determination of the study of thermal stability/degradation of waste hdpe in various ranges of temperature [1]. the tga and dtga curves of the pyrolysis of hdpe under nitrogen atmosphere obtained at three different heating rates of 4, 7 and 10 °c/min are shown in figures 2 and 3. a. s. abbas and m. g. saber / iraqi journal of chemical and petroleum engineering91,9 (2018) 93-99 41 fig. 2. tga of virgin hdpe at different heating rates in the figure (2) curve the initial temperature at which the degradation started and final temperature at which the degradation completed for waste hdpe was 370.2 and 492.8°c, 370.9 and 463.9 °c, 381 and 510 °c at the heating rates of 4, 7 and 10 °c/min, respectively. these results are in good agreement with recorded degradation temperature ranges for hdpe by al mustapha and andresen and by used a pyris 1 thermal gravimetric analyzer (tga1), at a heating rate of 10 °c/min from 35 to 900 °c in a nitrogen gas atmosphere with a flow rate of 20 ml/min [26], also aboulkas and harfi recorded that by used the rheometrix scientific sta 1500 tga analyzer at four different heating rates (2, 10, 20 and 50 k/min) between 300 k and 1273 k [28]. the rate of mass loss is temperature dependent: the higher the temperature, the larger the mass loss [14]due to the fact that polymer molecules does not have enough time to exhaust the heat with increasing heating rate, leading to slower decomposition rate [1]. it is clearly in figure (2) that there is a shift in the weight loss data to higher temperatures as the heating rate increases, because the rate of heat transfer at various heating rates is different, and the exposure time at the higher heating rate is shorter, as well as the effect of the kinetics of decomposition [18]. the same behavior was realized by several previous works [31][1]. dtga curves for waste hdpe at 4, 7 and 10 °c/min heating rates (figure 3) contains one peak this indicates that there is one degradation step at different heating rates[1]. the maximum degradation temperature (tmax) of hdpe takes place at 450, 410 and 405 °c at 10, 7 and 4 °c/min heating rates respectively as shown in figure 3. the recorded values of tmax for hdpe are in the range between 461 and 493 °c at hr equal to 10 °c/min [1,31,32]. fig. 3. dtga of virgin hdpe at different heating rates 3.2. conversion of hdpe and tga kinetics analysis the conversion versus tga temperature of hdpe at different heating rates is shown in figure 4. the conversion of hdpe increased with temperature at different heating rates. at 10, 7 and 4 °c/min the conversion increased from 8, 22, and 35 % at 390 °c respectively to 100% at 550 °c for all heating rate. fig. 4. conversion of virgin hdpe versus tga temperature at different heating rates 0 20 40 60 80 100 0 100 200 300 400 500 600 temperature, °c hr=10 °c/min hr=7 °c/min hr=4 °c/min a. s. abbas and m. g. saber / iraqi journal of chemical and petroleum engineering91,9 (2018) 93-99 41 the results obtained from tga were analyzed according to kas, fwo and cr methods to calculate the activation energy (ea) and pre-exponential factor (a). the kinetic parameters obtained by kas and fwo methods were calculated according to equations (7) and (8), respectively. the activation energy and preexponential factor were calculated as a function of conversion by using iso-conversional methods of kas and fwo methods for the range of conversion from 0.05 to 0.95 is considered for calculating the kinetic parameters by these methods. the iso-conversional plots of these methods are shown in figures 5 and 6 respectively. fig. 5. kas plots of hdpe at different values of conversion. fig. 6. fwo plots of hdpe at different values of conversion figure (7) was show that the activation energy depends upon extent of conversion for both kas and fwo methods. in general, the calculated values of activation energy by fwo were slightly higher but in the same order of magnitude for those calculated by kas. at the beginning of reaction, the activation energy values have oscillated in the same scale of about 120 and 136 kj/mole. after 65 % of hdpe converted the activation energy values rise to its higher values (203 to 204 kj/mol for kas and fwo, respectively). at 90% of hdpe conversion, the activation energy then lowering near the end of reaction to about 151 to 155 kj/mol for kas and fwo, correspondingly. fig. 7. the activation energy as a function of conversion using kas and fwo technique figure 8 shows the plot of the cr method for waste hdpe under non-isothermal conditions. in this figure, as the entire range of ln(-ln(1-x)/t 2 ) as a function of 1/t, the data could be represented by a single straight line for all three heating rates. reasonable fits of data to straight lines indicate that the assumption of first-order kinetics for thermal decomposition of waste hdpe is acceptable. the activation energy and pre-exponential factor values are shown in table 3. fig. 8. cr method plots of hdpe at different values of conversion a. s. abbas and m. g. saber / iraqi journal of chemical and petroleum engineering91,9 (2018) 93-99 41 table 3. calculated kinetic parameters for hdpe by cr method at different heating rate hr, ˚c/min ea, kj/mol a, min -1 10 175.866 3.35*10 12 7 156.6191 1.46*10 11 4 126.9964 4.83*10 8 activation energy increased with increase in heating rate due to very low thermal conductivity of polymeric material and hence the temperature maldistribution in the waste hdpe sample will be significant at a high heating rate [1] the average activation energy calculated by kas, fwo and cr are137.43, 141.52 and153.16 kj/mol respectively. these differences could be due to the approximations used for the temperature integral used in these methods [18,33], and are in good agreement with the reported activation energy[26,28,31,32]. 4conclusion the kinetic parameters of waste hdpe decomposition under non-isothermal conditions using tga were determined. determining the kinetic parameters also provides information to design more effective conversion systems and optimum decomposition regimes. the tga experiment showed that the degradation temperatures for waste hdpe at which the maximum weight losses take place were about 389.4, 398.2 and 434.1 °c at the heating rates of 4, 7 and 10 °c/min, respectively. the main pyrolysis process occurred in the temperature range 350 to 510 °c. the average activation energy values of waste hdpe have been calculated by kas, fwo and cr method are 137.43, 141.52 and 153.16 kj/mol respectively for firstorder decomposition reaction model. references [1] s. kumar and r. k. singh, “pyrolysis kinetics of waste high-density polyethylene using thermogravimetric analysis,” int. j. chemtech res., vol. 6, no. 1, pp. 131– 137, 2014. [2] s. kumar and r. k. singh, “recovery of hydrocarbon liquid from waste high density polyethylene by thermal pyrolysis,” brazilian j. chem. eng., vol. 28, no. 4, pp. 659–667, 2011. [3] c. cleetus, s. thomas, and s. varghese, “synthesis of petroleum-based fuel from waste plastics and performance analysis in a ci engine,” j. energy, vol. 2013, pp. 1–10, 2013. [4] m. f. ali and m. s. qureshi, “catalyzed pyrolysis of plastics : a thermogravimetric study,” vol. 5, no. 9, pp. 284–292, 2011. [5] m. a. ja, “production of liquid fuels from recycled plastics using acidic hnay catalysts,” 2011. [6] m. t. taghizadeh, p. seifi-aghjekohal, a. bahadori, and b. zeraatkar, “thermal and catalytic degradation study of polyethylene and investigation the catalytic effect of x-zeolite and silica-alumina on degradation kinetic,” j. iran. chem. res., vol. 2, pp. 195–210, 2009. [7] m. syamsiro, w. hu, s. komoto, s. cheng, p. noviasri, p. prawisudha, and k. yoshikawa, “coproduction of liquid and gaseous fuels from polyethylene and polystyrene in a continuous sequential pyrolysis and catalytic reforming system,” energy environ. res., vol. 3, no. 2, pp. 90– 106, 2013. [8] k. lee, “pyrolysis of waste polystyrene and highdensity polyethylene,” www.intechopen.com, 2011. [9] e. apaydin-varol, s. polat, and a. e. putun, “pyrolysis kinetics and thermal decomposition behavior of polycarbonate – a tga ftir study,” vol. 18, no. 3, pp. 833–842, 2014. [10] p. v thorat, s. warulkar, and h. sathone, “issn 2277 – 7164 review article thermofuel – „ pyrolysis of waste plastic to produce liquid hydroocarbons ,‟” vol. 3, no. 1, pp. 14–18, 2013. [11] e. rostek and k. biernat, “thermogravimetry as a research method in the transformation processes of waste rubber and plastic products for energy carriers (wte and wtl processes ),” vol. 1, no. 2, pp. 163–171, 2013. [12] x. g. li, b. g. ma, l. xu, z. t. luo, and k. wang, “catalytic effect of metallic oxides on combustion behavior of high ash coal,” energy and fuels, vol. 21, no. 5, pp. 2669–2672, 2007. [13] n. murichan and p. cherntongchai, “kinetic analysis of thermal degradation of polyolefin mixtures,” int. j. chem. eng. appl., vol. 5, no. 2, pp. 169–175, 2014. [14] m. heydari, m. rahman, and r. gupta, “kinetic study and thermal decomposition behavior of lignite coal,” vol. 2015, 2015. [15] k. slopiecka, p. bartocci, and f. fantozzi, “thermogravimetric analysis and kinetic study of poplar wood pyrolysis,” no. may, pp. 1687–1698, 2011. [16] a. marcilla, a. gómez-siurana, and d. berenguer, “study of the influence of the characteristics of different acid solids in the catalytic pyrolysis of different polymers,” appl. catal. a gen., vol. 301, no. 2, pp. 222–231, 2006. [17] s. mallakpour and m. taghavi, “the accuracy of approximation equations in the study of thermal decomposition behaviour of some synthesized optically active polyamides,” iran. polym. j., vol. 18, no. 11, pp. 857–872, 2009. [18] x. yongjiang, x. huaqing, w. hongyan, l. zhiping, and f. chaohe, “kinetics of isothermal and non-isothermal pyrolysis of oil shale,” oil shale, vol. 28, no. 3, p. 415, 2011. a. s. abbas and m. g. saber / iraqi journal of chemical and petroleum engineering91,9 (2018) 93-99 41 [19] s. polat, e. apaydın, and a. e. pütün, “tga ftir study on the thermal decomposition of tea waste,” 2013. [20] k. oluoti, t. richards, t. r. k. doddapaneni, and d. kanagasabapathi, “evaluation of the pyrolysis and gasification kinetics of tropical wood biomass,” bioresources, vol. 9, no. 2, pp. 2179– 2190, 2014. [21] m. s. alwani, h. p. s. abdul khalil, o. sulaiman, m. n. islam, and r. dungani, “an approach to using agricultural waste fibres in biocomposites application: thermogravimetric analysis and activation energy study,” bioresources, vol. 9, no. 1, pp. 218–230, 2014. [22] a. s. abbas and s. d. a shubar, “pyrolysis of high-density polyethylene for the production of fuellike liquid hydrocarbon,” iraqi j. chem. pet. eng., vol. 9, no. 1, pp. 23–29, 2008. [23] i. kayacan, “pyrolysis of low and high density polyethylene . part i : nonisothermal pyrolysis kinetics,” pp. 385–391, 2008. [24] f. a. m. ammar s. abbas, “production and evaluation of liquid hydrocarbon fuel from thermal pyrolysis of virgin polyethylene plastics,” iraqi j. chem. pet. eng., vol. 16, no. march, 2015. [25] a. s. abbas and f. a. mohamed, “kinetic study of hydrocarbon liquid production via thermal and catalytic pyrolysis for low-density polyethylene,” diyala j. eng. sci., vol. 08, no. january, pp. 819–834, 2016. [26] m. n. almustapha and j. m. andrésen, “recovery of valuable chemicals from high density polyethylene (hdpe) polymer : a catalytic approach for plastic waste recycling,” int. j. environ. sci. dev., vol. 3, no. 3, 2012. [27] s. s. idris, n. a. rahman, k. ismail, a. b. alias, z. a. rashid, and m. j. aris, “bioresource technology investigation on thermochemical behaviour of low rank malaysian coal , oil palm biomass and their blends during pyrolysis via thermogravimetric analysis ( tga ),” bioresour. technol., vol. 101, no. 12, pp. 4584–4592, 2010. [28] a. aboulkas and k. el harfi, “study of the kinetics and mechanisms of thermal decomposition of moroccan tarfaya oil shale and its kerogen,” oil shale, vol. 25, no. 4, pp. 426–443, 2008. [29] k. m. lu, w. j. lee, w. h. chen, and t. c. lin, “thermogravimetric analysis and kinetics of copyrolysis of raw/torrefied wood and coal blends,” appl. energy, vol. 105, pp. 57–65, 2013. [30] e. sima-ella, g. yuan, and t. mays, “a simple kinetic analysis to determine the intrinsic reactivity of coal chars,” fuel, vol. 84, no. 14–15, pp. 1920–1925, 2005. [31] s. c. o. hee taik kim, “kinetics of thermal degradation of waste polypropylene and polyethylene,” j. ind. eng. chem., vol. 11, pp. 648– 656, 2005. [32] ush, s. salman, jiri mojtaba, and p. mohammad, “thermal degradation mechanism of hdpe nanocomposites containing nano,” vol. 3, no. 6, pp. 15–28, 2014. [33] n. sbirrazzuoli, l. vincent, a. mija, and n. guigo, “chemometrics and intelligent laboratory systems integral , differential and advanced isoconversional methods complex mechanisms and isothermal predicted conversion – time curves,” chemom. intell. lab. syst., vol. 96, no. 2, pp. 219– 226, 2009. iraqi journal of chemical and petroleum engineering vol.12 no.4 (december 2011) 21-35 issn: 1997-4884 extraction of valuable metals from spent hydrodesulfurization catalyst by two stage leaching method wadood t. mohammed, nada s. ahmedzeki, mariam f. abdulnabi university of baghdad, colloge of engineering, chemical engineering department abstract spent hydrodesulfurization (co-mo/γ-al2o3) catalyst generally contains valuable metals like molybdenum (mo), cobalt (co), aluminium (al) on a supporting material, such as γ-al2o3. in the present study, a two stages alkali/acid leaching process was conducted to study leaching of cobalt, molybdenum and aluminium from co-mo/γal2o3 catalyst. the acid leaching of spent catalyst, previously treated by alkali solution to remove molybdenum, yielded a solution rich in cobalt and aluminium. keywords: spent hds catalyst; sodium carbonate; sulfuric acid; leaching; valuable metals introduction the petroleum refining industry makes extensive use of catalysts for desulphurization of various fractions. the most common hydrodesulphurization (hds) catalysts are the ni,mo and the co,mo both on the γ-alumina support [1]. during hydrodesulphurization reactions, the catalysts are deactivated by compounds of s, c, v, fe, ni, si and traces of as and p [2-4]. as a result, the spent catalysts are classified as hazardous materials [5]. due to their toxic nature, the disposal of spent catalysts can pollute the environment since heavy metals are leached out. to avoid pollution in land disposal as well as to minimize landfill space, the spent catalysts are subjected to metal extraction by various solubilization processes and reused in a variety of applications [6-8]. however, such waste materials containing high metal concentrations may be considered as “artificial ores” since they can serve as secondary raw materials with a consequent reduction in the demand for primary mineral resources. recycling of spent catalysts became an unavoidable task not only for lowering catalysts costs but also for reducing their waste to prevent the environmental pollution [1]. spent hds catalysts generally consist of 10– 30% molybdenum,1–12% vanadium, 0.5–6% nickel,1–6% cobalt, 8–12% sulphur, 10–12% carbon and the balance is alumina, which makes it economically viable for recovery of valuable metals [9]. during the past decade, more research work was conducted to recover molybdenum, vanadium and other valuable metals from spent hds catalysts [10]. a number of processes and technologies for the recycling of valuable metals from spent catalysts have been university of baghdad college of engineering iraqi journal of chemical and petroleum engineering extraction of valuable metals from spent hydrodesulfurization catalyst by two stage leaching method 22 ijcpe vol.12 no.4 (december 2011) available online at: www.iasj.net developed and reported [11-15]. basically, there are two main processes, hydrometallurgical and hydropyrometallurgical processes to recover valuable metals from spent catalysts [16]. hydrometallurgical processes involves leaching with alkaline or acidic solutions. many reagents, such as naoh, h2so4, nh3, (nh4)2so4 and oxalic acid with h2o2 and fe(no3)2 have been tested [17,8] hydropyrometallurgical processes such as calcination to remove the hydrocarbons, c and s followed by leaching with suitable reagent [18,19] or roasting of spent catalyst with na2co3, nacl and naoh at high temperatures followed by leaching [20,21,15] have been studied extensively for recovery of metals from spent hds catalyst. the objective of the work presented in this study is intended to investigate the best operating conditions of metal removal (i.e. mo, co and al) from spent como/γ-al2o3 catalyst by using two stages of extraction which contain alkali stage (i.e. sodium carbonate and hydrogen peroxide solution) and acid stage (i.e. sulfuric acid and hydrogen peroxide solution) [22]. experimental materials the following chemical agents were used in the experiments: 1. spent co-mo/γ-al2o3 catalyst. the spent co-mo/γ-al2o3 catalyst supplied from al-daura refinery was used. the shape of the catalyst was cylindrical (2.5mm x 1.5mm). catalyst contained residue of oil and washed by acetone then by distilled water and dried overnight in an oven maintained at 85 ᵒ c. finally, it was ground and sieved. for this study, two different size fractions of spent catalyst were prepared: (less than 75μm and greater than 75μm) and mixed thoroughly to obtain uniform sample for chemical analysis and leaching experiments. chemical analysis of the examined samples are shown in table (1). the analysis was done in ibn sina company by using atomic absorption analysis. table 1, chemical analysis of selected samples catalyst composition %co %mo %al co-mo/γ-al2o3 2.2 10.12 41.16 2. hydrogen peroxide (h2o2) supplied by applichem gmbh ollowg with assay of 50%. 3. sulfuric acid (h2so4) supplied by sd fine-chem limited with a concentration of 98%. 4. sodium carbonate (na2co3) analar. apparatus the apparatus used in the experiments was: 1. water bath equipped with temperature controller (baird and tatlaock unitemp water bath). 2. mechanical mixer, which was calibrated using a digital tachometer (victor dm6234p+). 3. three neck round – bottom flask (500ml) in volume. the general arrangement of equipments used for extraction are shown in fig. (1). fig. 1, schematic diagram of the apparatus unit 1 4 2 5 3 wadood t. mohammed, nada s. ahmedzeki, mariam f. abdulnabi available online at: www.iasj.net ijcpe vol.12 no.4 (december 2011) 23 experimental design two stage leaching process was studied: istudy of alkali leaching stage in this study, sodium carbonate and hydrogen peroxide as extractant agents were used to extract mo from spent catalyst. different parameters for this leaching stage were studied as listed below. 1. agitation time (30, 60, 90 and 120 minutes). 2. agitation speed (100, 300 and 500 rpm). 3. extractant concentration (sodium carbonate concentration of 40, 60, 80 and 120 g/l and hydrogen peroxide concentration of 5, 7, 10 and 12 vol.%). 4. pulp density (5, 10, 20 and 30 w/v%). 5. operating temperature (30, 50, 70 and 90 ° c) 6. particle size (greater than 75 μm and less than 75 μm). iistudy of acid leaching stage in this study, sulfuric acid and hydrogen peroxide as extractant agents were used to extract co and al. different parameters for this leaching stage were studied. 1. agitation time (30, 60, 90 and 120 minutes). 2. agitation speed (100, 300 and 500 rpm). 3. extractant concentration (sulfuric acid concentration of 10, 20 and 30wt.% and hydrogen peroxide concentration of 0, 0.05, 0.1 and 0.15 m) . 4. pulp density (5, 10, 20 and 30 w/v%). 5. operating temperature (30, 50, 70 and 90 ° c). experimental procedure alkali leaching stage in alkali leaching, the spent catalyst was ground and sieved. for this study, two different size fractions of spent catalyst were prepared: (less than 75μm and greater than 75μm) and mixed thoroughly to obtain uniform samples for leaching. the solution was prepared by dissolving a certain amount of sodium carbonate in deionized water to get different concentration of solution. leaching experiments were carried out by taking 200ml of leachant in 500ml round bottom flask fitted with a seal to avoid evaporation loss. the contents were stirred with mechanical mixer. after the temperature of the solution reached the desired value, a certain amount of catalyst with different ratios (s/l) was added to the flask and then hydrogen peroxide was added. the addition of h2o2 exothermic started the reaction. 10 ml samples were withdrawn at the end of each run and were filtered from residue by vacuum filtration using filtration paper and analyzed for mo, co and al. the analysis was made in ibn sina company by using atomic absorption technique. the recovery percentage was calculated by using the following relationship: …(1) acid leaching stage in acid leaching, the residue of alkali leaching was dried and analysis for mo, co and al. the solution was prepared by adding a certain amount of sulfuric acid to deionized water to get a different concentration of solution. leaching experiments were carried out by taking 200ml of leachant in 500ml round bottom flask fitted with a seal to avoid evaporation loss. the contents were stirred with mechanical mixer. after the temperature of the solution reached the desired value, a certain amount of catalyst with different ratios (s/l) was added to the flask then … 3.1 extraction of valuable metals from spent hydrodesulfurization catalyst by two stage leaching method 24 ijcpe vol.12 no.4 (december 2011) available online at: www.iasj.net hydrogen peroxide was added. 10 ml samples were withdrawn at the end of each run and were filtered from residue by vacuum filtration using filtration paper and analyzed for co and al. the analysis was made in ibn sina company using atomic absorption technique. the recovery percentage was calculated according to eq. (1). factors influencing the experiments alkali leaching stage effect of agitation time in this set of experiments, the effect of agitation time on mo extraction was investigated. a sample of solution was taken at the end of each period (30, 60, 90 and 120 min.). operating conditions (temperature=30 ᵒ c, agitation speed =300rpm, pd=20%, p.s.=less than 75μm, sodium carbonate concentration of 60g/l and 10vol.% hydrogen peroxide concentration) were kept constant. effect of agitation speed in this set of experiments, the effect of agitation speed on mo extraction was investigated. a sample of solution was taken at the end of each run of different speeds (100, 300 and 500 rpm) to determine the metals concentration. agitation time was fixed from the previous experiments. other variables such as temperature=30 ᵒ c, pd=20%, p.s.=less than 75μm, sodium carbonate concentration of 60g/l and 10vol.% hydrogen peroxide concentration were kept constant. effect of extractant concentration in this set of experiments, the effect of extractant concentration on mo extraction was investigated. a sample of solution was taken at the end of each run of a different concentration of sodium carbonate (40, 60, 80 and 120 g/l) at fixed hydrogen peroxide concentration (5, 7, 10 and 12 vol.%). from previous sections the agitation time and agitation speed were fixed. other variables such as operating temperature =30 ᵒ c, pd=20%,and p.s.=less than 75μm were kept constant. effect of pulp density in this set of experiments, the effect of pulp density on extraction of mo was investigated. different values of pulp density were tried (5, 10, 20 and 30 w/v%). the agitation time, agitation speed, sodium carbonate and hydrogen peroxide concentration were fixed from previous sections and other variables such as temperature =30 ᵒ c and p.s.= -75μm were kept constant. effect of temperature the effect of temperature on extraction of mo was investigated. the solution was heated to different temperatures (30, 50, 70 and 90 ᵒ c). the agitation time, agitation speed, pulp density, sodium carbonate and hydrogen peroxide concentration were fixed from previous sections while particle size was kept constant less than 75 μm. effect of particle size the effect of particle size on extraction of mo was investigated. particle size of catalyst less than 75μm or (>75μm) was used. the agitation speed, pulp density, temperature, sodium carbonate and hydrogen peroxide concentration were fixed from previous sections. acid leaching stage effect of agitation time in this set of experiments, the effect of agitation time on co and al extraction was investigated. a sample of solution was taken at the end of each period (30, 60, 90 and 120 min.). operating conditions (temperature=30 ᵒ c, agitation speed wadood t. mohammed, nada s. ahmedzeki, mariam f. abdulnabi available online at: www.iasj.net ijcpe vol.12 no.4 (december 2011) 25 =300rpm, pd=20%, sulfuric acid concentration of 10 wt.% and without hydrogen peroxide) were kept constant. effect of agitation speed in this set of experiments, the effect of agitation speed on co and al extraction was investigated. a sample of solution was taken at end of each run of different speeds (100, 300 and 500 rpm) to determine the metals concentration. agitation time was fixed from the previous experiments. other variables such as temperature=30 ᵒ c, pd=20%, sulfuric acid concentration of 10wt.% and without hydrogen peroxide were kept constant. effect of extractant concentration in this set of experiments, the effect of extractant concentration on extraction of co and al was investigated. a sample of solution was taken at the end of each run of a different concentration of sulfuric acid (10, 20 and 30 wt.%) at fixed hydrogen peroxide concentration (0, 0.05, 0.1and 0.15 m). from previous sections the agitation time and agitation speed were fixed. other variables such as operating temperature =30 ᵒ c and pd=20% were kept constant. effect of pulp density in this set of experiments, the effect of pulp density on extraction of co and al was investigated. different values of pulp density were tried (5, 10, 20 and 30 w/v%). the agitation time, agitation speed, sulfuric acid and hydrogen peroxide concentration were fixed from previous sections and temperature of 30 ᵒ c was kept constant. effect of temperature the effect of temperature on extraction of co and al was investigated. the solution was heated to different temperatures (30, 50, 70 and 90 ᵒ c). the agitation time, agitation speed, pulp density, sulfuric acid and hydrogen peroxide concentration were fixed from previous sections. results and discussion catalyst characterizations powder xrd analysis was performed on the deoiled sample in order to detect metal foulants such as sulfur, argon, titanium, iron and zinc that block the pore mouths and retarding the access of the reactants to the active sites of the catalyst with pores and identify different crystalline phases present in the catalyst. xrd pattern of spent como/γ-al2o3 catalyst is given in fig. (2). the analysis was done in the ministry of science and technology. fig. 2, x-ray parttern of spent como/γal2o3 catalyst alkali leaching stage effect of agitation time the obtained results are plotted in figs. (3-6) and fig. 6 illustrate the effect of operating conditions on mo, co and al. it is obvious that the extraction efficiency of mo increased as the agitation time was increased to a certain point where it remained extraction of valuable metals from spent hydrodesulfurization catalyst by two stage leaching method 26 ijcpe vol.12 no.4 (december 2011) available online at: www.iasj.net constant. the highest extraction efficiency of 56.37% for mo was obtained after 90 minutes because extraction processes proceed until equilibrium is reached. therefore, further increase in the time of experiment had no significant influence on the extraction. the results of angelidis et al (1995) [6] had also the same trend in selective dissolution of mo, co and ni from diesel and naphtha spent hydrodesulfurization catalyst and in agreement with shariat et al (2001) [19] in technical note optimizing conditions for hydrometallurgical production of purified molybdenum trioxide from roasted molybdenite of sarcheshmeh. co and al extraction was less than 1% at these operating conditions due to acidity. fig. 3, effect of agitation time on mo extraction fig. 4, effect of agitation time on co extraction fig. 5, effect of agitation time on al extraction fig. 6, effect of agitation time on metals extraction effect of agitation speed as seen from figs. (7-10), the stirring speed shows a small effect on the dissolution of metals within the range used. when the leaching time is 90 min, the stirring speed of 300 rpm gave the best extraction efficiency of mo (mo=56.37%). this indicates that the diffusion of the reactants from the solution towards the surface of a catalyst particle and the products away from the surface of the particle was fast and hence increasing agitation speed did not control the leaching rate within the range of the stirring speeds tested. all subsequent experiments were carried out at a stirring speed of 300 rpm. similar results were observed by mulak et al (2006) [1]; david (2007) [23] and qi-ming et al (2009) [24]. 0 20 40 60 0 50 100 150 % m o e x tr a ct io n time, min. mo 0 0.1 0.2 0.3 0.4 0.5 0 50 100 150 % c o e x tr a ct io n time, min. co 0 0.05 0.1 0.15 0.2 0.25 0 50 100 150 % a l e x tr a ct io n time, min. al 0 10 20 30 40 50 60 0 50 100 150 % m e ta l e x tr a ct io n time, min. mo co al wadood t. mohammed, nada s. ahmedzeki, mariam f. abdulnabi available online at: www.iasj.net ijcpe vol.12 no.4 (december 2011) 27 fig. 7, effect of agitation speed on mo extraction fig. 8, effect of agitation speed on co extraction fig. 9, effect of agitation speed on al extraction fig. 10, effect of agitation speed on metals extraction effect of extractant concentration as shown in fig. (11), a maximum efficiency of mo extraction was achieved around 60g/l na2co3 for 90 minutes and decreased gradually thereafter. where as, the percentage extraction of co and al was not significant when compared with mo extraction as shown in figs. (12-14). the effect of h2o2 addition varied in values of (5, 7, 10 and 12vol.%) at a constant concentration of na2co3 (60 g/l). the results are shown in figs. (15-18). the results showed a gradual decrease of mo leaching efficiency above 10 vol.% h2o2. whereas, the percentage extraction of co and al increased gradually, which is due to the acidic nature of the leach solution (decrease of ph). it was observed that, a particular concentration of na2co3 and h2o2 had a significant effect on maximum mo solubilization. at higher concentrations of either na2co3 or h2o2, a reaction with each other probably occurs forming sodium percarbonate and thereby decreases the availability of reactants to react with the catalyst, which causes a decrease in mo leaching efficiency as mentioned by park et al (2006b) [25]. leaching of spent catalyst with na2co3 in the presence of oxidizing agent such as h2o2 involves oxidation of sulphides to sulphate, which is exothermic, and the reaction of mo with sodium carbonate forming sodium molybdate. the role of oxidant is to break the mos2 complex and convert metal and s to the maximum oxidized state and oxidize the oil and free carbon to co2 and h2o. whereas, the role of na2co3 is to react with the liberated mo forming soluble sodium molybdate, neutralization of so3 produced during oxidation to soluble sodium sulphate, and thereby avoiding environmental problems. the reaction of molybdenum content of the spent catalyst in presence of na2co3 and 0 20 40 60 0 200 400 600 % m o e x tr a ct io n agitation speed, rpm mo 0 0.1 0.2 0.3 0.4 0.5 0 200 400 600 % c o e x tr a ct io n agitation speed, rpm co 0 0.05 0.1 0.15 0.2 0.25 0 200 400 600 % a l e x tr a ct io n agitation speed, rpm al 0 10 20 30 40 50 60 0 200 400 600 % m e ta l e x tr a ct io n agitation speed, rpm mo co al extraction of valuable metals from spent hydrodesulfurization catalyst by two stage leaching method 28 ijcpe vol.12 no.4 (december 2011) available online at: www.iasj.net h2o2 can be represented by equation [25]: mos2+3na2co3+h2o2+4o2 →na2moo4+2na2so4 +h2o + 3co2 …. (2) fig. 11, effect of sodium carbonate on mo extraction fig. 12, effect of sodium carbonate on co extraction fig. 13, effect of sodium carbonate on al extraction fig. 14, effect of sodium carbonate on metals extraction fig. 15, effect of hydrogen peroxide on mo extraction fig. 16, effect of hydrogen peroxide on co extraction fig. 17, effect of hydrogen peroxide on al extraction 0 20 40 60 0 50 100 150 % m o e x tr a ct io n [na2co3], g/l mo 0 0.2 0.4 0.6 0 50 100 150 % c o e x tr a ct io n [na2co3], g/l co 0 0.05 0.1 0.15 0.2 0.25 0 50 100 150 % a l e x tr a ct io n [na2co3], g/l al 0 10 20 30 40 50 60 0 50 100 150 % m e ta ls e x tr a ct io n [na2co3], g/l mo co al 0 20 40 60 0 5 10 15 % m o e x tr a ct io n [h2o2], vol.% mo 0 0.1 0.2 0.3 0.4 0.5 0 10 20 % c o e x tr a ct io n [h2o2], vol.% co 0 0.1 0.2 0.3 0 10 20 % a l e x tr a ct io n [h2o2], vol.% al wadood t. mohammed, nada s. ahmedzeki, mariam f. abdulnabi available online at: www.iasj.net ijcpe vol.12 no.4 (december 2011) 29 fig. 18, effect of hydrogen peroxide on metals extraction effect of pulp density by examining figs. (19-22), it can be seen that a maximum efficiency of mo extraction was achieved around 20%pd and decreased gradually thereafter with an increase in the pulp density. similar behavior was observed by park et al. (2006a) [26] in hydrometallurgical processing and recovery of molybdenum trioxide from spent catalyst. a large solid to liquid ratio increases the resistance for diffusion of fresh extractant to the surface of catalyst. therefore, requires longer time and requires higher extractant concentration as concluded by shariat et al (2001) [19]. fig. 19, effect of pulp density on mo extraction fig. 20, effect of pulp density on co extraction fig. 21, effect of pulp density on al extraction fig. 22, effect of pulp density on metals extraction effect of temperature as temperature increases from 30 to 90 ᵒ c, the mo extraction efficiency after 90 minutes leaching was improved from 56.37% to 75%. this is obvious in figs. (23-26). an increase in the extraction efficiency was observed with increasing the temperature. this may be attributed to the following reasons: 0 10 20 30 40 50 60 0 5 10 15 % m e ta ls e x tr a ct io n [h2o2], vol.% mo co al 0 20 40 60 0 20 40 % m o e x tr a ct io n pulp density, w/v% mo 0 0.1 0.2 0.3 0.4 0.5 0 20 40 % c o e x tr a ct io n pulp density, w/v% co 0 0.1 0.2 0.3 0.4 0 20 40 % a l e x tr a ct io n pulp density, w/v% al 0 10 20 30 40 50 60 0 20 40 % m e ta ls e x tr a ct io n pulp density, w/v% mo co al extraction of valuable metals from spent hydrodesulfurization catalyst by two stage leaching method 30 ijcpe vol.12 no.4 (december 2011) available online at: www.iasj.net  increasing leaching temperature will increase the rate of reaction between the solvent and value mineral. it was found that the relation between the rate of reaction and the temperature at which the reaction takes place can be represented by the arrhenius equation [27]. ( ) ... (3) where: k is the reaction rate constant.  increasing the temperature will increase the diffusion coefficient, since it also follows an arrhenius relationship [28]. ( ) … (4) where : d is the diffusion coefficient. similar results were observed by angelidis et al (1995) [6] in selective disolution of critical metals from diesel and naphtha hydrodesulfurization catalyst. fig. 23, effect of temperature on mo extraction fig. 24, effect of temperature on co extraction fig. 25, effect of temperature on al extraction fig. 26, effect of temperature on metals extraction effect of particle size it can be seen from figs. (27-29) that the particle size has a significant effect on dissolution of metals. it was found that the highest extraction efficiency was achieved at a catalyst particle size of less than 75μm. the mo extraction efficiency for (<75) and (>75) μm particle size reaches 75% and 56.46%, for co efficiency reaches 1.34% and 1.05% and for al reaches 0.98% and 0.77% after 90 minutes leaching, respectively. by decreasing the particle size, the contact area between the catalyst particle and the fluid is increased, therefore the reaction rate is increased which is also concluded by souza et al (2007) [29] and qi-ming et al (2009) [24]. since the acid leaching involved leaching of residue from alkali leaching, particle size was the same. 0 20 40 60 80 0 50 100 % m o e x tr a ti o n temperature, ᵒc mo 0 0.4 0.8 1.2 1.6 0 50 100 % c o e x tr a ct io n temperature, ᵒc co 0 0.5 1 1.5 0 50 100 % a l e x tr a ct io n temperature, ᵒc al 0 20 40 60 80 0 50 100 % m e ta ls e x tr a ct io n temperature, ᵒc mo co al wadood t. mohammed, nada s. ahmedzeki, mariam f. abdulnabi available online at: www.iasj.net ijcpe vol.12 no.4 (december 2011) 31 fig. 27, effect of particle size on mo extraction fig. 28, effect of particle size on co extraction fig. 29, effect of particle size on al extraction acid leaching stage effect of agitation time fig. (30) shows increasing of extraction efficiency with increasing the agitation time which was also observed by anglidis et al (1995) [6], mulak et al (2006) [1], david (2007) [23] and qi-ming et al (2009) [24]. experiments showed that 90 minutes contact time is sufficient enough to reach equilibrium between solid phase and aqueous phase. only co and al seem to dissolve considerably, and small quantities of remaining mo were detected in leachate. the quantity of dissolved al was considerably higher than the one achieved during alkali leaching experiments, since alumina is readily soluble in acids as mentioned by anglidis et al (1995) [6]. fig. 30, effect of agitation time on metals extraction effect of agitation speed the results presented in fig. (31), show that the leaching of cobalt and aluminum is independent of the stirring speed. in the study on a spent hds catalyst leaching with sulfuric acid, mulak et al (2005) [30] also observed similar behavior of stirring speed on the leaching kinetics. this indicates that the external diffusion of h2so4 and coso4 between the fluid and the surface of particles is fast due to small particle size, and hence does not control the dissolution of metals within the investigated range of stirring speed. all subsequent experiments were carried out at a stirring speed of 300 rpm in order to assure the invariance of this parameter. fig. 31, effect of agitation speed on metals extraction 0 50 100 0 20 40 60 80 time , min. % m o e x tr a ct io n mo extraction at p.s.=-75 mo extraction at p.s.=+75 mo μm μm 0 0.5 1 1.5 0 50 100 % c o e x tr a ct io n time , min. co extraction at p.s.=+75μm co extraction at p.s.=75μm co 0 0.2 0.4 0.6 0.8 1 1.2 0 50 100 % a l e x tr a ct io n time, min. al extraction at p.s.=75μm al extraction at p.s. =+75μm al 0 5 10 15 20 25 30 35 40 0 50 100 150 % m e ta l e x tr a ct io n time , min. co al 0 5 10 15 20 25 30 35 40 0 200 400 600 % m e ta l e x tr a ct io n agitation speed, rpm co al extraction of valuable metals from spent hydrodesulfurization catalyst by two stage leaching method 32 ijcpe vol.12 no.4 (december 2011) available online at: www.iasj.net effect of extractant concentration as shown in fig. (32), the effect of sulfuric acid concentration on cobalt and aluminum extraction efficiency increases with increasing the sulfuric acid concentration. for 10 wt.% concentration, there is virtually an acid deficiency effect. nevertheless, there is no beneficial effect of increasing acid concentration more than 20%. however, after elapsing a certain time, namely, 90 minutes, the metals extraction efficiency practically remains constant. the increase in the extraction of co and al may be due to the following reasons:  the high penetrative of acid through the solid particle.  the high reaction rate between the acid and metals. these results are in agreement with angelidies et al (1995) [6] and qiming et al (2009) [24]. the cobalt extraction efficiencies after 90 minutes extraction with 10%, 20% and 30% sulfuric acid are found to be 35.93%, 40.43% and 40.43%, respectively and for aluminum extraction efficiencies are found to be 6.53%, 8.84% and 8.86%, respectively. the influence of h2o2 concentration on the extraction of cobalt and aluminum from the spent como/γal2o3 catalyst was determined by varying the initial concentration of h2o2 from 0.0 to 0.15m at 30 ᵒ c in 20wt.% h2so4 solution. fig. (33) shows summarized metals extraction after 90 minutes extraction. generally, the extraction of co and al gradually increased up to 0.1m h2o2 and then remained constant. this behavior may be explained by the fact that as the acid concentration in the medium increases, the apparent rate of solid product (coso4) increases, and the internal diffusion resistance of h2so4 through the product layer is enhanced. consequently, the dissolution process slows down. the extraction of al was practically not affected by the concentration of h2o2 within the whole range. the highest extraction of cobalt (48%) and aluminum (8.8%) was observed in 20wt.% h2so4 solution with 0.1m h2o2 at 30 ᵒ c during the 90 minutes leaching. hydrogen peroxide was added to h2so4 solution to help metals dissolution from spent catalyst. these results were in agreement with results of mulak et al (2006) [1] in preliminary results of ni, mo, al and v leaching from a spent nimo/γ-al2o3 catalyst and david (2007) [23] on extraction of valuable metals based on cu, ni /γ-al2o3. fig. 32, effect of sulfuric acid concentration on metals extraction fig. 33, effect of hydrogen peroxide concentration on metals extraction effect of pulp density fig. (34) indicates that no significant variations were observed on the dissolution of the valuable metals with 0 5 10 15 20 25 30 35 40 45 0 20 40 % m e ta l e x tr a ct io n [h2so4], wt.% co al 0 5 10 15 20 25 30 35 40 45 50 0 0.05 0.1 0.15 % m e ta l e x tr a ct io n [h2o2], m co al wadood t. mohammed, nada s. ahmedzeki, mariam f. abdulnabi available online at: www.iasj.net ijcpe vol.12 no.4 (december 2011) 33 the increase in the solid to liquid ratio. thus 20%pd was the best value for metals extraction. this trend might indicate that equilibrium leaching conditions were reached even by using the lower solid to liquid ratio. these results are in agreement with david (2007) [23]. fig. 34, effect of pulp density on metals extraction effect of temperature the temperature increas from 30 to 90 ᵒ c caused the cobalt extraction efficiency after 90 minutes leaching to be improved from 48% to 93.2% and for aluminum from 8.8% to 54.3% according to arrhenius eq. (3) and eq. (4) as shown in fig. (35). these results are in agreement with angelidis et al (1995) [6] and qi-ming et al (2009) [24]. fig. 35, effect of temperature on metals extraction conclusions for the present investigation and operating conditions used, it may be concluded that:  for alkali leaching: 1. alkali leaching for mo extraction by using na2co3 and h2o2, the equilibrium was reached after 90 minutes of contact time. 2. agitation speed had small effect on the extraction of mo and 300rpm gave the best result. 3. the rate of mo extraction increased with increasing in na2co3 and h2o2 concentrations to 60 g/l and 10vol.%, respectively and, thereafter, decreased gradually. 4. a maximum efficiency of mo was achieved around 20% pd and, thereafter, decreased gradually. 5. the results indicate that increasing the temperature from 30 to 90 ° c lead to an increasing in the mo extraction from 69.12% to 75%. 6. the rate of mo extraction increased with decreasing the particle size. the particle size which is less than 75µm gave the best extraction than the particle size which greater than 75µm. 7. the results showed that the process controlled by both mass and reaction mechanisum.  for acid leaching: 1. acid leaching for extraction of co and al by using h2so4 and h2o2, the equilibrium was reached after 90 minutes of contact time. 2. agitation speed had small effect on co and al extraction and 300rpm gave the best result. 3. the rate of co and al extraction increased with increasing h2so4 and h2o2 concentrations up to 40.43% and 48% for cobalt and up to 8.84% and 8.8% for aluminum and remained constant thereafter. 4. it was found that no significant variations on the dissolution of co and al with the increase in pulp density. 0 10 20 30 40 50 60 0 20 40 % m e ta l e x tr a ct io n pulp density, (w/v)% co al 0 20 40 60 80 100 0 50 100 % m e ta l e x tr a ct io n temperature, ᵒc co al extraction of valuable metals from spent hydrodesulfurization catalyst by two stage leaching method 34 ijcpe vol.12 no.4 (december 2011) available online at: www.iasj.net 5. the rate of co and al extraction increased with increasing the temperature up to 90 ° c. 6. the results showed that the process was controlled by both mass and reaction mechanisum. references 1. mulak, w., szymczycha, a., lesniewicz, a., żyrnicki, w., (2006), “ preliminary results of metals leaching from a spent hydrodesulphurization (hds) catalyst”, physicochemical problems of mineral processing, 40, 69-76. 2. trim, d.l., (1989), “deactivation, regeneration and disposal of hydroprocessing catalyst, in: catalysts in petroleum refining. trim, d.l., akasha, s., absihalabi, m. and bishara, a., (editors), elsevier, amsterdam, 1990, pp. 41-60. 3. diez, f., gattes, b.c., (1990), “deactivation of a ni-mo/γ-al2o3 catalyst: influence of coke on the hydroprocessing activity”, ind. eng. chem. res., 29, 1999-2004. 4. furimsky, e., massoth, f.e., (1999), “deactivation of hydroprocessing catalysts”, catalysis today, 52, 381-495. 5. loehr, r.c., rogers, l.a., erickson, d.c., (1993), “mobility of residues at petroleum industry hazardous waste land treatment sites”, water res., 27, 1127-1138. 6. angelidis, t.n., tourasanidis, e., marinou, e., stalidis, g.a., (1995), “selective dissolution of critical metals from diesel and naphtha spent hydrodesulphurization catalysts”, resources, conservation and recycling, 13, 269-282. 7. furimsky, e., (1996), “spent refinery catalysts: environment, safety and utilization”, catalysis today, 30, 223-286. 8. marafi, m., stanislaus, a., (2003a), “options and processes for spent catalyst handling and utilization”, journal of hazardous materials b, 101, 123–32. 9. biswas, r.k., wakihara, m., taniguchi, m., (1986), “characterization and leaching of the heavy oil desulphurization waste catalyst”, bangladesh journal of scientific and industrial research, 21, 228–237. 10. chen, y., feng, q., shao, y., zhang, g., qu, l., lu, y., (2006a), “research on the recycling of valuable metals in spent al2o3based catalyst”, mineral engineering, 19, 94-97. 11. zhang, p., inoue, k., (1995), “recovery of metal values from spent hydrodesulphurization catalysts by liquid-liquid extraction”, energy and fuels, 9, 231–9. 12. sun, d., li, x.z., brungs, m., trimm, d., (1998), “encapsulation of heavy metals on spent fluid catalytic cracking catalyst”, water science and technology, 38, 211– 217. 13. sun, d., tay, j.h., cheong, h.k., leung, d.l.k., qian, g.r., (2001a), “recovery of heavy metals and stabilization of spent hydrotreating catalyst using a glass– ceramic matrix”, journal of hazardous materials b, 87, 213– 223. 14. van den berg, j.a.m., yang, y., nauta, h.h.k., van sandwijk, a., reuter, m.a., (2002), “comprehensive processing of low grade sulphidic molybdenum ores”, minerals engineering, 15, 879–883. 15. kar, b.b., murthy, b.v.r., misra, v.n., (2005), “extraction of molybdenum from spent catalyst by salt-roasting”, international journal of mineral processing, 76, 143–147. wadood t. mohammed, nada s. ahmedzeki, mariam f. abdulnabi available online at: www.iasj.net ijcpe vol.12 no.4 (december 2011) 35 16. zeng, l., cheng, c.y., (2009) “a literature review of the recovery of molybdenum and vanadium from spent hydrodesulphurisation catalysts part i: metallurgical processes”, hydrometallurgy, 98, 1-9. 17. siemens, r.e., jong, b.w., russell, j.h., (1986), “potential of spent catalysts as a source of critical metals”, conservation & recycling 9, 2, 189-196. 18. wiewiorowski, e., tinnin, r. and crnoievich, r., (1988), “a cyclic process for recovery of metals from spent catalyst”, presented at the sme annual meeting, phoenix, az, 25-28, preprint no. 88-168. 19. shariat, m.h., setoodeh, n., atash dehghan, r., (2001), “optimizing conditions for hydrometallurgical production of purified molybdenum trioxide from roasted molybdenite of sarcheshmeh”, miner. eng., 14, 815–820. 20. mukherjee, t.k., bose, d.k., gupta, c.k., (1980), “studies on molybdenum extraction”, in: sohn, h.y., carlson, o.n., smith, j.m. (eds.), extractive metallurgy of refractory metals. the metallurgical society of aime, warrendale, u.s.a, pp. 25. 21. kar, b.b., datta, p., misra, v.n., (2004), “spent catalyst: secondary source for molybdenum recovery”, hydrometallurgy, 72, 87–92. 22. mohammed, w.t., ahmedzeki, n.s., abdulnabi, m.f., “extraction of valuable metals from spent hydrodesulfurization catalyst by two stage leaching method”, m.sc. thesis, university of baghdad (2011). 23. david, e., (2007), “extraction of valuable metals from amorphous solid wastes”, journal of achievements in materials and manufacturing engineering, 25, 1518. 24. qi-ming, f., yan-hai, s., leming, o., guo-fan, z., yi-ping, l., (2009), “kinetics of nickel leaching from roasting-dissolving residue of spent catalyst with sulfuric acid”, j. cent. south univ. technol., 16, 0410−0415. 25. park, k.h., mohapatra, d., reddy, b.r., (2006b), “selective recovery of molybdenum from spent hds catalyst using oxidative soda ash leach/carbon adsorption method”, journal of hazardous materials b, 138, 311–6. 26. park, k.h., mohapatra, d., reddy, b.r., nam, c.w., (2006a), “hydrometallurgical processing and recovery of molybdenum trioxide from spent catalyst”, international journal of mineral processing, 80, 261–5. 27. park, r.h., (1978), “an introduction to chemical metallurgy”, pergamon press, england, 2 nd ed. 28. jackson, e., (1986), “hydrometallurgical extraction and reclamation”, ellis horwood limited. 29. souza, a.d., pina, p.s., lima, e.v.o., da silva, c.a., leão, v.a., (2007), “kinetics of sulphuric acid leaching of a zinc silicate calcine [j]”, hydrometallurgy, 89(3/4), 337−345. 30. mulak, w., miazga, b., szymczycha, a., (2005), “kinetics of nickel leaching from spent catalyst in sulphuric acid solution [j]”, international journal of mineral processing,77(4), 231−235. available online at https://ijcpe.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.19 no.1 (march 2018) 51 – 56 issn: 1997-4884 corresponding authors: majid i. abdul-wahab a , email: na, bashaer m. namoos, email: bashaermahmood@yahoo.com iraqi journal of chemical and petroleum engineering kinetic of disinfection reaction by sodium hypochlorite solution majid i. abdul-wahab a and bashaer m. namoos a chemical engineering department, college of engnerring, baghdad university abstract the present studier aims to study the kinetic of reaction at different experimental conditions depending on coliform bacteria concentration and hypochlorite ion. the effects that had been investigated were different of sodium hypochlorite doses, contact time, ph and temperature (20, 29, 37) o c. the water samples were taken from al-wathba water treatment plant in risafa side of tigris river in baghdad. the biological tests included the most probable number (m.p.n) for indicating the concentration of coliform bacteria with different contact times and the total plate count (t.p.c) for indicating the amount of colonies for general bacteria. the iodimetry method (chemical test) was used for indicating the concentration of hypochlorite ion with different contact times. different models were examined to fit the experimental data including the kinetics power law (first and second order) and selleck model. it was found that the selleck model fitted well the experimental data in which degree of selleck model was equal to two and the rate constants was 1.3791 x 10 -5 l / (mole min) at 20 o c, 3.0806 x 10 -5 l / (mole min) at 29 o c, and 5.738 x 10 -5 l / (mole min) at 37 o c. keywords: selleck model, coliform bacteria, disinfection, sodium hypochlorite, and chlorine 1introduction disinfection process is very important for killing the microorganisms that remain in the water after treatment. there are different types of disinfectant reagents used to disinfect drinking water such as, chlorine (cl2), chloride dioxide (clo2), ozone (o3), chloramines (nh2cl), sodium hypochlorite (naocl), calcium hypochlorite (ca(ocl)2) and lithium hypochlorite (liocl) ‎[1]‎[1]. typically, disinfection is applied as a final stage in the water treatment. the determined disinfectant amount added firstly should achieve its effect directly leaving sufficient amount of residuals for the next disinfection through the distribution system to ensure microbial regrowth ‎[2]. boccelli et al. ‎[3] reported that these effects of disinfectant are quite beneficial, although kopfler et al. ‎[4] mentioned that the disinfection by-products (dbps) which result from the side reactions between the disinfectant and natural organic matters (noms) could be carcinogenic. however bielmeier et al. ‎[5] during their genetic work on animals, proved development of some cancers of liver, stomach and renal failure. chlorine is one of the most widely distributed elements on earth, it is not found in a free state in nature. instead, it exists mostly in combined-ion with sodium, potassium, calcium and magnesium. elemental chlorine is a heavy gas of greenish-yellow color, with a characteristic irritating and pen-etrating odor. chlorine must have been known to all chemists for many centuries, but only in 1809, sir humphrey davy concluded that chlorine gas was an element and because of its characteristic yellow-green color, propose the name. chlorine gas (cl2) is used for drinking water disinfection due to its high oxidation potential, low cost, and excellent disinfection effectiveness, but the disadvantages of using free chlorine is a high and non selective reactivity leading to produce undesirable products. free chlorine can rapidly react with noms in water by oxidation, addition and substitution reactions to form dbps ‎[6]. when chlorine is added to the water, it undergoes the following reactions ‎[1]: (1) (2) the dissociation of cl2 depends on the ph value and the equilibrium between hocl and ocl _ is maintained even through hocl is constantly consumed through its germicidal function. it appears that the disinfecting efficiency of chlorine decreases with an increasing in ph and vice vers, which is parallel to the concentration of undissociated hypochlorous acid ‎ [1]. disinfection by sodium hypochlorite (naocl) is the oldest and most widely used of active chlorine compounds in chemical disinfection due to its powerful germicides, free of poisonous residuals, easy to handle, and most economical to use. sodium hypochlorite solutions range in concentration from 1% to 15%, with 1% to 5% available chlorine products employed for domestic use ‎[1]. sodium hypochlorite solution is a clear liquid which can be fed through solution feed equipment without fear of clogging. it is normally diluted to 1% solution before application; it tends to lose strength if exposed to sunlight for long time before use ‎[7]. m. i. abdul-wahab a and b. m. namoos/ iraqi journal of chemical and petroleum engineering91,9 (2018) 51-56 25 when naocl hydrolyzes in pure water solution, the reactions in equations (3) (4) occur indicating that the ratio of hocl / ocl depends on the ph of the solutions, with low ph favoring the formation of hocl and vice versa, ‎[8]. the use of sodium hypochlorite solutions for disinfection was also reported to introduce chlorate ion into drinking water. under some conditions, the strength of hypochlorite can significantly decline in just a few days. in fact, stability is one of the major issues that must be addressed in operating with sodium hypochlorite. bolyard et al. ‎[9] found that chlorate ions can be formed during the manufacture and storage of hypochlorite solutions. hypochlorite ions are known to disproportionate in basic solution to produce clo3 as it shown in equation (5): ‎[10] (3) (4) (5) coliform bacteria can transferred to human by drinking water or food that had been contaminated with them. coliform bacteria are used as an indicator for contamination of drinking water because coliforms may be associated with the sources of pathogens contamination and the analysis of drinking water for coliform are relatively simple, economical, and efficient ‎[11]. the exceptions of using coliform as an indicator is when there is any availability of diseasesproduction organisms, especially protozoa so the suible treatment for any can kill all coliform bacteria in the water ‎[12]. coliform are shown to produce amount of d-lactate, ethanol, and acetic acid plus traces of l-lactate from glucose ‎[13]. this work was aimed to study the kinetics of the disinfection reaction and finding the suitable kinetic model that fit the experimental data. 2experimental work the experimental work includes disinfection process for treated water using sodium hypochlorite (naocl) solution. different experimental conditions were investigated as listed below: 1ph values of (6.5, 7.4, 8), 2doses of sodium hypochlorite (naocl) solution (5, 10, 20) ppm, 3contact times (0, 5, 15, 30, 60, 90, 120) min., and 4temperature (20, 29, 37) o c batch reactor with magnetic stirrer was used for disinfection process in which one liter of a glass beaker was used for making the reactor. different doses of 1% naocl solution were added to one liter of treated water. samples were taken from the disinfected water for each contact times for the biological and chemical tests. the biological tests included the most probable number (m.p.n) for indicating the concentration of coliform bacteria with different contact time and the total plate count (t.p.c) for indicating the amount of colonies for general bacteria at time = 0. the iodimetry method (chemical test) was used for indicating the concentration of hypochlorite ion with different contact times. m.p.n test at time = 0 had been performed using three dilutions (0.1, 0.01, 0.001), for each dilution one set of five tubes of single l.t.b media had been used, 1ml of each dilution had been injected in each tube of its tubes set. for other times of contact, 20ml of the sample had been injected in each tube of the five triple l.t.b media tubes. for the iodimetry test, 25ml of water sample had been used by adding ki to get light yellow color titration was done by using starch until the color change to blue then titrated by sodium thiosilfet until the color became invisible ‎[14]. 2.1. sample collection the water samples were taken from al-wathba water treatment plant in risafa side of tigires river, they were from the second sedimentation tank of al-kefah line project so the samples were with no chlorine addition and with a turbidity range ntu (4.5-18), ph values between (7.36-7.66), electrical conductivity ec (684-939 µs/cm) and for temperature the range is (14.5-18 o c) . the samples were kept in ice at temp.= 0, to prevent bacteria from division. samples had been transformed during 24 hour to the laboratory. 2.2. incubation procedure the initial m.p.n test tubes at time = 0 and the petri dish of t.p.c test were kept in the incubator ( memmert ) at 37 0 c for 48 hour, while the m.p.n tubes for other time contact times 5, 15, 30, 60, 90, and 120 min were kept in the same incubator at 37 0 c for 24 hs ‎[14]. 3results and discussion 3.1. results for m.p.n tests effects of ph values three ph values of 6.5, 7.4, and 8 were used to investigate the effect of solution acidity on the disinfection process by hypochlorite solution. fig. 1, fig. 2 and fig. 3 show the decay in fecal coliform bacteria for higher values of ph, i. e, 7.4 and 8. it can be seen that the decay in the concentration is more rapid for larger values of ph. this was interpreted by styler and rumsey ‎[13]. they showed that when the ph value of the water increased from 6.5 which is the ideal value, that will lead to increasing in amount of food intake by the coliform bacteria from the media and that casing increases in producing lactic acid and acetic acid as food west product for the glucose sugar that been consumed by the bacteria as food from the media, the increasing in the amount of acetic acid and lactic acid will lead to reduce in the value m. i. abdul-wahab a and b. m. namoos/ iraqi journal of chemical and petroleum engineering91,9 (2018) 51-56 25 of ph of the media. on the other hand, these results revealed a decrease in the (n/no) ratio with the increase in the dose of naocl solution due to increase in the hocl concentration and ocl concentration, since the affinity of the pathogens killing were also increased, similer effects were reported by rajput and polprasert ‎[8]. fig. 1. decay of fecal coliform concentration with time no = 1300 coliform/l, tpc = 51 colony, ph = 6.5 and temp.= 29 o c fig. 2. decay of fecal coliform concentration with time no = 1300 coliform/l, tpc = 51 colony, ph = 7.4 and temp.= 29 o c fig. 3. decay of fecal coliform concentration with time no = 1300 coliform/l, tpc = 51 colony, ph = 8 and temp.= 29 o c 3.2. effect of temperature disinfection experiments were carried out at different temperatures which were 37, 20, and 29 0 c to examine the effect of temperature on the rate of disinfection reaction. from fig. 4, fig. 5 and the previous fig. 2 it can be noticed that the ratio of fecal coliform bacteria concentration to its initial concentration (n/n0) was lowered when the temperature was increased due to increasing the rate of reaction ‎[15]. fig. 4. decay of fecal coliform concentration with time no = 1300 coliform/l, tpc = 51 colony, ph = 7.4 and temp.= 20 o c fig. 5. decay of fecal coliform concentration with time no = 1300 coliform/l, tpc = 51 colony, ph = 7.4 and temp.= 37 o c 3.3. results for iodimetry tests effects of ph values increasing ph values from 6.5 (table 1) to 7.4 (table 2) and to 8 (table 3) leads to sharp decrees in the number of coliform bacteria, reducing the consume of hocl in which it needed for the pathogens killing process and that lead to increasing the amount of accumulated hypochlorite ion (ocl ) in water. hypochlorite ion (ocl ) is producing from the decay of hocl as it shown in equation (4). m. i. abdul-wahab a and b. m. namoos/ iraqi journal of chemical and petroleum engineering91,9 (2018) 51-56 25 table 1. hypochlorite ion concentration for different contact times, no = 1300 coliform/l, tpc = 51 colony, ph = 6.5 and temp.= 29 o c time min. ocl *10 -3 mole/l dose 5ppm ocl *10 -3 mole/l dose 10ppm ocl *10 -3 mole/l dose 20ppm 0 0.67 1.35 2.7027 5 0.0402 0.0494 0.0579 15 0.0165 0.0193 0.0224 30 0.0097 0.0112 0.0131 60 0.0056 0.0065 0.0077 90 0.0044 0.0051 0.0062 120 0.0033 0.0046 0.0059 table 2. hypochlorite ion conc. with different contact time, no = 1300 coliform/l, tpc = 51 colony, ph = 7.4 and temp.= 29 o c time min. ocl *10 -3 mole/l dose 5ppm ocl *10 -3 mole/l dose 10ppm ocl *10 -3 mole/l dose 20ppm 0 0.67 1.35 2.7027 5 0.0494 0.0671 0.0784 15 0.0193 0.0261 0.0311 30 0.0112 0.0155 0.0185 60 0.0077 0.0092 0.0171 90 0.0062 0.0079 0.0167 120 0.0046 0.0073 0.0161 table 3. hypochlorite ion conc. with different contact time, no = 1300 coliform/l, tpc = 51 colony, ph = 8 and temp.= 29 o c time min. ocl *10 -3 mole/l dose 5ppm ocl *10 -3 mole/l dose 10ppm ocl *10 -3 mole/l dose 20ppm 0 0.6711 1.35 2.7027 5 0.0784 0.1109 0.2057 15 0.0307 0.0479 0.0686 30 0.0185 0.0239 0.0611 60 0.0184 0.0171 0.058 90 0.0183 0.0114 0.0387 120 0.0180 0.0113 0.0289 3.4. effect of temperature it can be noticed from (table 4) and (table 5) that the concentration of ocl after 5 minutes of reaction at a temperature of 20 o c (0.018 x 10 -3 mole/ l) is much lower than that at 37 o c at the same operating conditions (0.0494x10 -3 mole/ l ). this can be explained as increasing the reaction temperature will increase the rate of reaction, in which montgomery [16] showed that the decaying process of the naocl solution to hocl and ocl is increased with the increasing in the temperature. table 4. hypochlorite ion concentration for different contact times, no = 1300 coliform/l, tpc = 51 colony, ph = 7.4 and temp. = 20 o c time min. ocl *10 -3 mole/l dose 5ppm ocl *10 -3 mole/l dose 10ppm ocl *10 -3 mole/l dose 20ppm 0 0.6711 1.3514 2.7027 5 0.018 0.022 0.024 15 0.007 0.008 0.012 30 0.004 0.006 0.006 60 0.003 0.003 0.004 90 0.002 0.0028 0.0038 120 0.0019 0.0023 0.003 table 5. hypochlorite ion concentration for different contact times, no = 1300 coliform/l, tpc = 51 colony, ph = 7.4 and temp. = 37 o c time min. ocl *10 -3 mole/l dose 5ppm ocl *10 -3 mole/l dose 10ppm ocl *10 -3 mole/l dose 20ppm 0 0.6711 1.3514 2.7027 5 0.125 0.144 0.171 15 0.042 0.057 0.068 30 0.024 0.034 0.045 60 0.017 0.026 0.032 90 0.0015 0.015 0.0173 120 0.0014 0.014 0.017 3.5. kinetics of disinfection reaction in the present work, experimental data were used to demonstrate the kinetics of the disinfection reaction when using sodium hypochlorite solution as a disinfectant. fig. 6 shows the relationship between the fecal coliform ratio (n/no) and contact times after disinfection by naocl for 1300 fecal coliform bacteria, t.p.c= 51 of bacteria colonies respectively, for first order of harriet chick model ‎[16]. fig. 6. first order model for coliform concentration ratio to its initial concentration vs. contact times no = 1300 coliform/l, tpc = 51 colony, ph = 6.5 and temperature= 29 o c m. i. abdul-wahab a and b. m. namoos/ iraqi journal of chemical and petroleum engineering91,9 (2018) 51-56 22 harriet chick first order model failed to unfit straight line. another trial was made to fit the experimental data to the second order reaction model. fig. 7 shows the response to the second order model as it is shown in equation 6 using integral method ‎[15], it shows that the second order power law model was unable to fit the experimental data of the reaction of sodium hypochlorite with water and this is in agreement with the results of gordon et al. ‎[17]. (6) fig. 7. second order model for hypochlorite ion concentration vs. contact times no = 1300 coliform/l, tpc = 51 colony, ph = 6.5 and temperature= 29 o c the general power low formula which is shown in equation 7 had been tested using 0.1% error percent microsoft visual basic program to fit the experimental data for coliform bacteria concentration decay with time by integral method. the coliform bacteria concentration and contact times were applied in the program. the formula had failed to fit well the experimental data due to the variation in values of rate constant (k) and reaction’s order (n) [15]. – (7) the failure of using first and second order models and the formula rn = -k n n led to try the “selleck model” which was used earlier by selleck (1978) to describe chlorine inactivation of coliform bacteria in wastewater effluent. although the selleck model was initially derived for chlorine inactivation of bacteria in wastewater, it is an empirical model and therefore applicable to any chemical disinfectant, organism and test water ‎[18]. selleck model can be expressed as ( ) (8) the calculations were done by using a less or equal 9% error percent of microsoft visual basic program to fit the experimental data of the present work for ocl and fecal coliform bacteria concentrations. the average value of n in the model was found to be equal 2 as it is shown in fig. 8, fig. 9, and fig. 10. table 6. the values of k for different temperature temperature in o c k in l / (mole . min) 20 1.3791 x 10 -5 29 3.0806 x 10 -5 37 5.738 x 10 -5 fig. 8. selleck model for hypochlorite ion concentration vs. fecal coliform concentration no = 1300 coliform/l, tpc = 51 colony, ph = 6.5 and k=3.0806 x 10 -5 l / (mole min) fig. 9. selleck model for hypochlorite ion concentration vs. fecal coliform concentration no = 1300 coliform/l, tpc = 51 colony, ph = 7.4 and k=1.379 x10 -5 l / (mole min fig. 10. selleck model for hypochlorite ion concentration vs. fecal coliform concentration no = 1300 coliform/l, tpc = 51 colony, ph = 7.4 and k=5.738 x 10 -5 l/ (mole) m. i. abdul-wahab a and b. m. namoos/ iraqi journal of chemical and petroleum engineering91,9 (2018) 51-56 25 4conclusions the following conclusions can be drawn from the present work 1the reaction between sodium hypochlorite solution (naocl) and water is fast in which coliform bacteria concentration is reduced sharply in the first five minutes. 2when ph value rises above 6.5, the coliform bacteria concentration is reduced. the best optimum ph value of the disinfection reaction is 8 according to the range used in this study. 3rate of disinfection increases with the increasing in the reaction temperature up to 37 o c. 4the power low kinetic model (first and second order) fails to fit the experimental data, while selleck kinetic model fit well the experimental data with a value of reaction order equal 2 acknowledgments the authors wish to express their thanks to the head and the members of alwathba water treatment plant laboratory and the department of biology of baghdad university for their help to produce this project. references [1] seymour, s. b., (2001), “disinfection, sterilization and preservation”, 5 th edition. lippincott williams and wilkins, chapter 3, pp: 201. [2] al samarae, r. h., (2001), “effection of economical on the quality of the drinking water in baghdad city and the damage on the citizens health”, m.sc. thesis, baghdad university, environmental engineering department. [3] boccelli, d. l., tryby, m. e., uber, j. m., and summers, r.s., (2003), “a reactive species model for chlorine decay and thm formation under rechlorination conditions”, water research, vol. 37, no. 1 pp: 26542666. [4] kopfler, r.c., and bull, r.j., (1991), “health effects of disinfectants and disinfection by-products”, journal awwa, vol. 49. no.5 pp: 8795. [5] bielmeier, s.r., best, d.s., guidici, d.l. and narotsky, m.g., (2001), “prenancy loss in the rat caused by bromodichloromethane”, toxicology sci., vol. 59, no. 2, pp: 15309. [6] gang, d. d., segar, r. l., clevenger, t. e. and banerji, s. k., (2002), “using chlorine demand to predict tthms and haa9 formation”, journal awwa, vol. 94, no. 10, pp: 7686. [7] who seminar pack for drinking-water quality. “disinfectants and disinfection by-products”, (1993).www.who.int/water_sanitation_health/dwq/s1 3.pdf [8] rajput, v. s., and polprasert, c., (1984), “study on chlorine disinfection of pond effluent”, water research, vol. 18, no. 5, pp: 513518. [9] bolyard, m., fair, p. s., and hautman, d. p., (1993), “sources of chlorate ion in us drinking water”, journal awwa, vol. 85, no. 9, pp: 8187. [10] chris, b., and martin, k., (2009), “basic water treatment”, 4 th edition, thomas telford limited, 1 heron quay, london e14 4jd, uk, chapter 12, pp: 214. [11] “coliform bacteria and drinking water” (2009). www.ewashtenaw.org/government/.../eh_coliformfa ctsheet.pdf [12] department of environmental quality, “coliform bacteria fact sheet” (2009). www.michigan.go/.../dep/depwcucoliformbactiwellwatersampling-270604-7.pdf [13] slyter, l. l., and rumsey, t. s., (1991), “effect of coliform bacteria, feed deprivation by steer or continuous-culture microbial populations changed from forage to concentrates”, journal of animal science, vol. 69, pp: 3055-3066. [14] apha standard methods for the examination of water and west water, (2005), 21 st edition. american public health association, washington d. c., pp: 61188. [15] levenspiel, o., (1999), “chemical reaction engineering”, 3 rd edition, johan wiley and sons, chapter 3, pp: 3944. [16] kerry, h., john, c. c., david, w., hand, r., rhodes, t., and george, t., “water treatment principles and design”, (2012), 3 rd edition, john wiley & sons, chapter 13, pp: 532538. [17] gordon, g., adam, l., and bubnis, b., (1995), “minimizing chlorate ion formation”, journal awwa, vol. 87, no. 6, pp: 97-106. [18] lee, y., and nam, s., (2002), “reflection on kinetic model to the chlorine disinfection for drinking water production”, the journal of microbiology, vol. 40, no. 2, pp: 119124. https://books.google.iq/books?hl=en&lr=&id=3f-kpj17_tyc&oi=fnd&pg=pr11&dq=disinfection,+sterilization+and+preservation&ots=knblia3si1&sig=tnrq3bq4vdgj2-bo14ihrpqaynu&redir_esc=y#v=onepage&q=disinfection%2c%20sterilization%20and%20preservation&f=false https://books.google.iq/books?hl=en&lr=&id=3f-kpj17_tyc&oi=fnd&pg=pr11&dq=disinfection,+sterilization+and+preservation&ots=knblia3si1&sig=tnrq3bq4vdgj2-bo14ihrpqaynu&redir_esc=y#v=onepage&q=disinfection%2c%20sterilization%20and%20preservation&f=false https://books.google.iq/books?hl=en&lr=&id=3f-kpj17_tyc&oi=fnd&pg=pr11&dq=disinfection,+sterilization+and+preservation&ots=knblia3si1&sig=tnrq3bq4vdgj2-bo14ihrpqaynu&redir_esc=y#v=onepage&q=disinfection%2c%20sterilization%20and%20preservation&f=false https://www.sciencedirect.com/science/article/pii/s0043135403000678 https://www.sciencedirect.com/science/article/pii/s0043135403000678 https://www.sciencedirect.com/science/article/pii/s0043135403000678 https://www.sciencedirect.com/science/article/pii/s0043135403000678 https://www.sciencedirect.com/science/article/pii/s0043135403000678 http://bases.bireme.br/cgi-bin/wxislind.exe/iah/online/?isisscript=iah/iah.xis&src=google&base=repidisca&lang=p&nextaction=lnk&exprsearch=75761&indexsearch=id http://bases.bireme.br/cgi-bin/wxislind.exe/iah/online/?isisscript=iah/iah.xis&src=google&base=repidisca&lang=p&nextaction=lnk&exprsearch=75761&indexsearch=id http://bases.bireme.br/cgi-bin/wxislind.exe/iah/online/?isisscript=iah/iah.xis&src=google&base=repidisca&lang=p&nextaction=lnk&exprsearch=75761&indexsearch=id https://academic.oup.com/toxsci/article/59/2/309/1667198 https://academic.oup.com/toxsci/article/59/2/309/1667198 https://academic.oup.com/toxsci/article/59/2/309/1667198 https://academic.oup.com/toxsci/article/59/2/309/1667198 http://www.jstor.org/stable/41298469?seq=1#page_scan_tab_contents http://www.jstor.org/stable/41298469?seq=1#page_scan_tab_contents http://www.jstor.org/stable/41298469?seq=1#page_scan_tab_contents http://www.jstor.org/stable/41298469?seq=1#page_scan_tab_contents http://apps.who.int/iris/bitstream/handle/10665/42274/who_ehc_216.pdf;jsessionid=b1a8bffb701d023ea5a66d1683b77193?sequence=1 http://apps.who.int/iris/bitstream/handle/10665/42274/who_ehc_216.pdf;jsessionid=b1a8bffb701d023ea5a66d1683b77193?sequence=1 http://apps.who.int/iris/bitstream/handle/10665/42274/who_ehc_216.pdf;jsessionid=b1a8bffb701d023ea5a66d1683b77193?sequence=1 http://apps.who.int/iris/bitstream/handle/10665/42274/who_ehc_216.pdf;jsessionid=b1a8bffb701d023ea5a66d1683b77193?sequence=1 https://www.sciencedirect.com/science/article/pii/0043135484901970 https://www.sciencedirect.com/science/article/pii/0043135484901970 https://www.sciencedirect.com/science/article/pii/0043135484901970 http://www.jstor.org/stable/41294369?seq=1#page_scan_tab_contents http://www.jstor.org/stable/41294369?seq=1#page_scan_tab_contents http://www.jstor.org/stable/41294369?seq=1#page_scan_tab_contents https://books.google.iq/books?hl=en&lr=&id=_d-2ttk1sfqc&oi=fnd&pg=pp11&dq=basic+water+treatment&ots=ggwqzbdb-q&sig=0kqsv3zwbc72bnfsc7ff1gopd2a&redir_esc=y#v=onepage&q=basic%20water%20treatment&f=false https://books.google.iq/books?hl=en&lr=&id=_d-2ttk1sfqc&oi=fnd&pg=pp11&dq=basic+water+treatment&ots=ggwqzbdb-q&sig=0kqsv3zwbc72bnfsc7ff1gopd2a&redir_esc=y#v=onepage&q=basic%20water%20treatment&f=false https://books.google.iq/books?hl=en&lr=&id=_d-2ttk1sfqc&oi=fnd&pg=pp11&dq=basic+water+treatment&ots=ggwqzbdb-q&sig=0kqsv3zwbc72bnfsc7ff1gopd2a&redir_esc=y#v=onepage&q=basic%20water%20treatment&f=false https://books.google.iq/books?hl=en&lr=&id=_d-2ttk1sfqc&oi=fnd&pg=pp11&dq=basic+water+treatment&ots=ggwqzbdb-q&sig=0kqsv3zwbc72bnfsc7ff1gopd2a&redir_esc=y#v=onepage&q=basic%20water%20treatment&f=false http://www.michigan.go/.../dep/dep-wcu http://www.michigan.go/.../dep/dep-wcu https://academic.oup.com/jas/article/69/7/3055/4705203 https://academic.oup.com/jas/article/69/7/3055/4705203 https://academic.oup.com/jas/article/69/7/3055/4705203 https://academic.oup.com/jas/article/69/7/3055/4705203 https://academic.oup.com/jas/article/69/7/3055/4705203 https://pubs.acs.org/doi/abs/10.1021/ie990488g?journalcode=iecred https://pubs.acs.org/doi/abs/10.1021/ie990488g?journalcode=iecred https://pubs.acs.org/doi/abs/10.1021/ie990488g?journalcode=iecred https://books.google.iq/books?hl=en&lr=&id=lslhaaaaqbaj&oi=fnd&pg=pr9&dq=water+treatment+principles+and+design&ots=p_hbrhx2lt&sig=pplvkgp_5vz78zij7zcstravcxi&redir_esc=y#v=onepage&q=water%20treatment%20principles%20and%20design&f=false https://books.google.iq/books?hl=en&lr=&id=lslhaaaaqbaj&oi=fnd&pg=pr9&dq=water+treatment+principles+and+design&ots=p_hbrhx2lt&sig=pplvkgp_5vz78zij7zcstravcxi&redir_esc=y#v=onepage&q=water%20treatment%20principles%20and%20design&f=false https://books.google.iq/books?hl=en&lr=&id=lslhaaaaqbaj&oi=fnd&pg=pr9&dq=water+treatment+principles+and+design&ots=p_hbrhx2lt&sig=pplvkgp_5vz78zij7zcstravcxi&redir_esc=y#v=onepage&q=water%20treatment%20principles%20and%20design&f=false https://books.google.iq/books?hl=en&lr=&id=lslhaaaaqbaj&oi=fnd&pg=pr9&dq=water+treatment+principles+and+design&ots=p_hbrhx2lt&sig=pplvkgp_5vz78zij7zcstravcxi&redir_esc=y#v=onepage&q=water%20treatment%20principles%20and%20design&f=false https://onlinelibrary.wiley.com/doi/abs/10.1002/j.1551-8833.1995.tb06382.x https://onlinelibrary.wiley.com/doi/abs/10.1002/j.1551-8833.1995.tb06382.x https://onlinelibrary.wiley.com/doi/abs/10.1002/j.1551-8833.1995.tb06382.x https://www.researchgate.net/profile/lee_yoon_jin/publication/228698833_reflection_on_kinetic_models_to_the_chlorine_disinfection_for_drinking_water_production/links/546463770cf2c0c6aec50966/reflection-on-kinetic-models-to-the-chlorine-disinfection-for-drinking-water-production.pdf https://www.researchgate.net/profile/lee_yoon_jin/publication/228698833_reflection_on_kinetic_models_to_the_chlorine_disinfection_for_drinking_water_production/links/546463770cf2c0c6aec50966/reflection-on-kinetic-models-to-the-chlorine-disinfection-for-drinking-water-production.pdf https://www.researchgate.net/profile/lee_yoon_jin/publication/228698833_reflection_on_kinetic_models_to_the_chlorine_disinfection_for_drinking_water_production/links/546463770cf2c0c6aec50966/reflection-on-kinetic-models-to-the-chlorine-disinfection-for-drinking-water-production.pdf https://www.researchgate.net/profile/lee_yoon_jin/publication/228698833_reflection_on_kinetic_models_to_the_chlorine_disinfection_for_drinking_water_production/links/546463770cf2c0c6aec50966/reflection-on-kinetic-models-to-the-chlorine-disinfection-for-drinking-water-production.pdf ijcpe vol.10 no.1 (march 2009) iraqi journal of chemical and petroleum engineering vol.9 no.4 (december 2007) 43-52 issn: 1997-4884 removal of dyes from wastewater of textile industries using activated carbon and activated alumina wadood taher mohammed * , hasan f. farhood * and abbas hassoon bjaiyah al-mas'udi * chemical engineering department college of engineering university of baghdad – iraq abstract this work was carried to study the capability of activated alumina from bauxite compared with activated carbon adsorption capability to reduce the color content from al-hilla textile company wastewater. six dyes were studied from two types(reactive and dispersed) namely (blue, red, yellow) from wastewater and aqueous solutions. forty eight experiments were carried out to study the effect of various initial conditions (bed height, flow rate, initial concentration, ph value, temperature, and competitive adsorption) on adsorption process. the results showed that the adsorption process using activated carbon insured a good degree of color reduction reaching (99.7%) and was better than activated bauxite which reached (95%). introduction wastewater from the textile industry can contain a variety of polluting substances including dyes. the pollution problem is different for the various types of fibers (1). color is the first contaminant to be recognized in the wastewater and has to be removed before discharging into water bodies or on land. the presence of very small amounts of dyes in water (less than 1 ppm for some dyes) is highly visible and affects the aesthetic merit, water transparency and gas solubility in lakes, rivers and other water bodies. the removal of color from water is often more important than the removal of the soluble colorless organic substances, which usually contribute the major fraction of the biochemical oxygen demand(bod).dyes, however , are more difficult to treat because of their synthetic origin and mainly complex aromatic molecular structures (2). sorption has been involved into one of the most effective physical processes for decolorization of textile wastewaters. the most commonly used adsorbent for color removal is activated carbon, because of its capability for efficiently adsorbing a broad range of different types of adsorbates. however, its use is limited because of its high cost. several researchers have been studying the use of alternative materials: agricultural, forest, animal and several low cost industrial by products such as peat, wood, tree barks, chitin, silica gel, bauxite, bentonite clay, certain synthetic adsorbents, etc. (3) activated carbon adsorption systems though widely used are very expensive and the regeneration cost is also very high. therefore, their use in wastewater treatment may be economically not feasible. there is, therefore, a need to identify and study the adsorptive characteristics of low cost alternatives. (4) the use of nonconventional adsorbents, particularly those that can be easily regenerated, to replace activated carbon in the removal of color from dye wastewater has been recently proposed. (5) textile wastewaters are usually complex. the composition is very variable and can change quickly. wastewaters from dyeing and subsequent rising steps are one of the largest contributions to wastewater generation in the textile industry. (6) in the fixed bed adsorption operation, the waste water to be treated is passed through a stationary bed of adsorbent. a fixed bed adsorber offers the advantage of simple operation plus the ability to serve as a filter for simultaneous suspended solids removal. fixed bed university of baghdad college of engineering iraqi journal of chemical and petroleum engineering removal of dyes from wastewater of textile industries using activated carbon and activated alumina 44 ijcpe vol.10 no.1 (march 2009) adsorber is used when the mass transfer zone is short (saturation of the adsorbent occurs shortly after initial breakthrough ) , two or more beds are used in series to increase the contact time,(i.e., increasing the efficiency of adsorbent utilization). two or more beds also can be combined in parallel to increase the capacity of adsorbent (i.e., when a high flow rate must be divided into a number of column, each column will treat a specific amount of influent). (7&8) in the application of adsorption for purification of water and wastewater, the material to be adsorbed commonly will be a mixture of many compounds rather than a single one. it is readily apparent that the presence of other solutes in the mixture adversely affects the adsorption of the first, leading to a much more rapid breakthrough of this material.(9) there are many factors affecting the adsorption process including the packed bed height, temperature, ph, influent concentration, flowrate, adsorbate molecular weight and mixing of more than one adsorbate.(1) experimental work the adsorbents used in the experimental work were activated carbon and activated alumina with the physical properties shown in tables 1 and 2. table (1) physical properties of ac activated alumina (aa). table (2) physical properties of aa adsorbates: wastewater which was supplied by alhilla textile company with six of the most commonly used dyes which are to be reactive and disperse classes, as listed in table (3). the aquatic solutions used in the experiments contained r. blue dye which was taken as a patteren. the solvent used was distilled water. table (3) different dyes molecular weights bulk density (kg/m 3 ) 350 particle density (kg/m 3 ) 1800 surface area(m 2 /kg) 680*10 3 void fraction 0.4 internal porosity 0.2 sieve opening (mm) 0.4 0.9 1.4 bulk density (kg/m 3 ) 665 average particle size (mm) 4.1 pore volume (cc/gm) 0.05 surface area (m 2 /kg) 345*10 3 color white sieve opening (mm) 2 3.2 4.8 6.4 dye molecular weight reactive red 875.5 reactive yellow 716 reactive blue 562 disperse blue 420 disperse red 371.5 disperse yellow 289 wadood taher mohammed, hasan f. farhood and abbas hassoon bjaiyah al-mas'udi 45 ijcpe vol.10 no.1 (march 2009) procedure and equipments: packing four beds were packed with various heights by the two adsorbents as shown in table (4). table (4): adsorbents weights and packed heights column length (m) adsorbent weight (g) activated carbon activated bauxite 0.1 13.2 21.8 0.15 19.8 32.7 0.2 26.4 43.6 0.25 33 54.5 twenty six experiments were carried out on wastewater containing 0.05 kg/m3 of r. blue dye as the initial influent concentration; eight for bed heights (0.1, 0.15, 0.2, 0.25) m, six for flow rates of wastewater (1.66, 2.55, 5)*10-5 (m3/min), six for ph values (4, 6, 8) and six for influent temperatures (290, 300, 310) (k). twenty two experiments were carried out on aquatic solutions; six for influent concentrations (0.03, 0.04, 0.05 kg/m3) of r. blue color, twelve for color types (six types), one for r. blue dye pure solution, and two for pure solutions mixture of the dyes. half of the above experiments were carried out for every adsorbent in the same conditions. equipments two cylindrical columns (qvf) of (0.3) m in length, and internal diameter of (0.02) m. were used. one was packed with activated carbon and the second with activated bauxite. the columns were packed with adsorbents particles which were confined with a very fine screen to prevent losses of the particles. experiment procedure: the wastewater or aqueous solution was passed through the adsorbent column in the down flow direction with the different experimental conditions (flowrates, solution ph and solution temperatures) through different packed bed heights. for each run of experiments the column was replaced by another bed with the same specifications. a sample of (5 ml) was taken every (5 minutes) duration and kept in a sample tube and then tested. analysis a cintra -5 gbc scientific equipment uvvisible spectrometer (computerized) and cecilce 1011 uv visible spectrometer were used to determine the solutions concentration of the dye in the samples taken from the tests performing results and discussion effect of packed bed height the experiments were carried out on wastewater solution on different adsorbent beds with heights of (0.1, 0.15, 0.2, 0.25 m) . keeping other conditions constant (influent conc, =0.05 kg/m3 , temp. =290 k , flow rate = 1.66*10-5 m3 /min ,ph=6). the main effect of the bed height in the adsorption process is on the capacity of adsorbent. since increasing the bed height will provide extra particles and additional surface area, there will be a remarkable increase in the adsorbent capacity. in addition increasing in the bed height will increase the contact time between the pollutant and adsorbent particles that will provide enough time for pollutants to penetrate into the particles of the adsorbent(10). figs.(1) and (2) indicate that the increase in bed height will increase the breakthrough point value in each adsorbents bed. for activated carbon this value was higher due to the difference in surface area. fig.(3) shows the adsorption quantities for both adsorbents. it can be seen that the adsorption capacity increased as the packed bed height increased. the total quantity of dye removed by activated carbon was greater than that removed by activated bauxite because the rate of adsorption is proportional to adsorbent surface. fig.(4) shows the effect of packed bed height on both adsorbents mass transfer rates. this was directly influenced with the bed height and also in activated carbon this rate was greater than in bauxite. effect of flow rate the experiments were carried out on wastewater solution at different flow rates (1.66, 2.55, 5)*10-5 m3/min. keeping other conditions constant (temp. = 290 (k), c (inf) = 0.05 (kg/m3), h=0.2m, ph = 6, r. blue dye). the effect of flow rate on the adsorption process is very important .this effect is based on the assumption that removal of dyes from wastewater of textile industries using activated carbon and activated alumina 46 ijcpe vol.10 no.1 (march 2009) film diffusion is the rate limiting in early portion of the column .increasing the flowrate in this region may be expected to make a compression or reduction of the surface film .therefore, this will decrease the resistance to mass transfer and increase the mass transfer rate. also, because the reduction in the surface film is due to disturbance created when the flow of the influent increases resulting from the easy passage of pollutants through the particles and entering easily to the pores(10). fig.(5) and fig.(6)show that the variable flowrates (in the range used) had a small effect on the adsorption capacity and adsorption mass rate, but the breakthrough point was inversely related with the flowrate as shown in fig.(7). also activated carbon had the greater adsorption capacity and mass rate, which was due to its greater surface area. effect of solution ph the experiments were carried out on wastewater solution with different solution ph (4, 6, 8). the other initial conditions were kept constant (h = 0.15m, t = 290 (k), f = 1.66*10-5 (m3/min), c (inf) = 0.05 (kg/m3), r. blue dye). ph strongly influences the adsorption as hydrogen and hydroxide ions are adsorbed and the charge of the other ions are also influenced by ph of the solution. for typical organic pollutants from industrial wastewater the adsorption increases with decreasing ph. (1) fig.(8) shows that the breakthrough point is inversely related with ph value. and fig.(9) shows that the total amount of dye removed from the solution at any period of time increases with decreasing ph values for both adsorbents and activated carbon removed greater amounts. this can be explained on the basic of formation of a positively charged surface on the adsorbent. a low ph value quite probably results in a lowering of the decrease of the negative charge on the adsorbent, thus changing the adsorption of the negatively charged adsorbate. (5) fig.(10) indicates the effect of ph value on the adsorption mass rate, it can be seen that this rate is inversely related with ph values. effect of temperature the experiments were carried out on wastewater solution at different temperatures of (290, 300, 310) (k). all other conditions were kept constant (h = 0.2 m, ph = 6, flowrate = 2.5*10-5 (m3/min), r. blue dye). normally the adsorption reactions are exothermic, which means that the adsorption will increase with decreasing temperature, although small variations in temperature do not tend to alter the adsorption process to a significant extent.(1&11) the adsorption capacity and adsorption mass rate were inversely related with temperature as shown in figs.(11) and (12), due to the fact that the adsorption reactions are exothermic, then high temperatures would inhibit or slow down the adsorption process. effect of influent concentration the experiments were carried out on aqueous solution at different pure dye initial concentrations (0.03, 0.04, 0.05) (kg/m3). keeping other conditions constant at (h = 0.2 m, ph = 6, t = 290 k, f = 2.5*10-5 (m3/min), r .blue dye). figure (13) shows that the adsorption quantity at any period increases with increasing the dye influent concentration. figure (14) shows that the adsorption mass transfer rate also increases with increasing the influent concentration or the dye for both adsorbents where it was greater in activated carbon due to the difference in its surface area. the initial concentration is inversely related to the adsorption equilibrium time. this may be explained by the fact that since the rate of diffusion is controlled by the concentration gradient, it takes a longer contact time to reach adsorption equilibrium for the case of low initial solute concentration values. because adsorption rate is limited by diffusion, variables that influence diffusion have a significant effect on the adsorption rate. for example, a higher concentration gradient across the surface of the adsorbent particle will increase the rate of adsorption (10&11). effect of dye type molecular size is of significance if the adsorption rate is controlled by antiparticle transport, in which the reaction generally proceeds more rapidly with the smaller adsorbate molecule. large molecules of one chemical wadood taher mohammed, hasan f. farhood and abbas hassoon bjaiyah al-mas'udi 47 ijcpe vol.10 no.1 (march 2009) class sorb more rapidly than smaller ones of another if higher energies (driving forces) are involved (1&11&12). to study the effect of the dye type on the adsorption behavior twelve experiments were carried out on the six types of dyes from their pure aqueous solutions separately, under constant conditions (ph=6, t=290 k, h=0.15m, f= 1.66*10-5 (m3/min) and c(inf)=0.05(kg/m3)). different dyes (reactive; red, blue, yellow, and dispersed; red, blue, yellow) with molecular weights of (875.5, 562, 716, 371.5, 420, and 289) respectively were tested. from fig.(15) it can be seen that the higher molecular weight dye the higher adsorption quantity. the tendency of higher molecular weight to adsorption was due to two reasons: the first was the decrease of solubility with the increase in molecular weight, and the second was the higher affinity to adsorbent surface by the larger molecular weight dye (9). figure (16) shows the effect of molecular weight in pure dye solution on the mass transfer rate of adsorption. it can be seen that the molar rate of uptake decreases with increasing molecular weight and the activated carbon has more mass transfer rate than the activated bauxite for the same packed bed. this is due to the larger surface area of the first. effect of competitive adsorption when adsorption occurs from a mixture of substances there is a competition between the various adsorptive for the interface. the presence of other solutes in the mixture adversely affects the adsorption of the first, leading to a much more rapid breakthrough of this material (9). to study the competitive adsorption of the dyes, two experiments were carried on r. blue dye from its pure solution at conditions (h=0.15m, ph=6, t=290 k, f=1.66*10-5 m3/min, c=0.05 kg/m3), and compared with wastewater solution at the same conditions as illustrated in figures (17) and (18). those figures indicate the difference between the breakthrough curves (c/co vs. t) on the two adsorbents. it is readily apparent that the presence of other solutes in the mixture adversely affects the adsorption of the first, leading to a much more rapid breakthrough of the dye. effect of pure mixtures solution two experiments on two adsorbents separately were carried to study the effect of a competitive adsorption resulting from a mixture of pure dyes solutions at a concentration of (0.03) (kg/m3) for every dye and the other initial conditions were kept constant (ph=6, t = 290 k, h = 0.15m, f = 1.66*10-5 (m3/min), c(inf) = 0.03 (kg/m3)). the comparison between adsorption from mixture solution and pure dye solution was shown in figs.(19) and (20), the same effect in the previous section can be seen. the effect of competitive adsorption on adsorption capacity is shown in fig. (21). it can be seen that the adsorption capacity increases as the molecular weight increases, and in activated carbon it is greater figure (22) shows the effect of molecular weight in the mixture of pure dye solutions on the mass transfer rate of adsorption where it can decreases as the molecular weight increases. it can be seen that the activated carbon had more mass transfer rate than the bauxite for the same packed bed; due to its larger surface area. fig (1): breakthrough curves of isothermal adsorption for different packed bed heights (r.blue, bauxite) removal of dyes from wastewater of textile industries using activated carbon and activated alumina 48 ijcpe vol.10 no.1 (march 2009) fig (2): breakthrough curves of isothermal adsorption for different packed bed heights (r. blue, carbon) fig (3): effect of packed bed height on adsorption capacity on both adsorbents (r. blue) fig(4) :effect of bed height on the rate of mass transfer on both adsorbents (r. blue) fig (5): adsorption quantity for different flowrates (r. blue, bauxite) fig (6): adsorption quantity for different flow rates (r. blue, carbon) fig (7): breakthrough curves of isothermal adsorption for different flow rates (r. blue, bauxite) wadood taher mohammed, hasan f. farhood and abbas hassoon bjaiyah al-mas'udi 49 ijcpe vol.10 no.1 (march 2009) fig (8): breakthrough curves for different ph values (r. blue, bauxite) fig (9): effect of ph value on adsorption capacity on both adsorbents (r. blue) fig (10): effect of ph value on the rate of mass transfer on both adsorbents (r. blue) fig (11): effect of influent temperature on adsorption capacity on both adsorbents (r. blue) fig (12): effect of influent temperature on the rate of mass transfer on both adsorbents (r. blue) fig (13): adsorption quantity for different influent initial concentrations (r. blue, bauxite) removal of dyes from wastewater of textile industries using activated carbon and activated alumina 50 ijcpe vol.10 no.1 (march 2009) fig (14): effect of influent concentration on mass transfer rate on both adsorbents (r. blue) fig (15): effect of molecular weight on the capacity of adsorption on both adsorbents fig (16): effect of molecular weight of dye from pure solution on mass transfer rate of adsorption for both adsorbent fig (17): comparison between breakthrough curves for adsorption of r. blue dye from its pure solution and from waste water dyes solution (bauxite) fig (18): comparison between breakthrough curves for adsorption of r. blue dye from its pure solution and from waste water dyes solution (carbon) fig (19): comparison between breakthrough curves for adsorption of r. blue dye from its pure solution and from mixture pure dyes solution (bauxite) wadood taher mohammed, hasan f. farhood and abbas hassoon bjaiyah al-mas'udi 51 ijcpe vol.10 no.1 (march 2009) fig (20): comparison between breakthrough curves for adsorption of r. blue dye from its pure solution and from mixture dyes solution (carbon) fig (21): effect of pure mixture dyes solution on adsorption capacity on both adsorbent fig (22): effect of molecular weight in dye mixture solution on mass transfer rate of adsorption for both adsorbents conclusions 1. sorption was an effective process for decolorization of textile dyes. although activated carbon was the most effective sorbent due to the high surface area, another low cost sorbent (activated bauxite) could be used for color removal. 2. the time to breakthrough point decreases with: the decrease in bed height, molecular weight of dye in both pure and mixture solution. 3. the increase in flow rate, ph value, initial concentration of dye in the influent, and temperature. 4. the capacity of adsorption increases with: the increase in bed height, influent concentration and dye molecular weight. 5. the decrease in flow rate, temperature, and ph value. 6. the rate of mass transfer for initial stage of adsorption increases with increasing in influent concentration, flow rate, and bed height and also with decreasing in ph value, molecular weight and temperature. 7. the adsorption rate and, therefore the adsorption capacity of the activated carbon are greater than that for the activated bauxite (255*10-5 kg color/kg carbon) and (133*10-5 kg color/kg bauxite) respectively. that is due to the fact that for the same bed height column the weight of the carbon was less than the bauxite because of its smaller bulk density; (bulk densities for the adsorbents used were (350 and 665) (kg/m3) for activated carbon and activated bauxite respectively). 8. the adsorption process using activated carbon had a good degree of color reduction, reaching 99.7%, and for activated bauxite it reached 95%. references 1. sven erik jorgenson, "industrial waste water management", amsterdam, oxford, new york (1979). 2. yongie miao, "biological remediation of dyes in textile effluent: a review on current treatment technologies", www. ccee. iastate edu/ corses/ ce s21/yongjie. 3. e. voudrias, k. fytianos, e. bozani, "sorption and desorption isotherms of dyes from aqueous solutions and wastewaters with different sorbent materials", global nest: the int. j. , vol.4, no.1, pp. 75-83,(greece), 2002 (internet). removal of dyes from wastewater of textile industries using activated carbon and activated alumina 52 ijcpe vol.10 no.1 (march 2009) 4. ajay meena &chitra rajagopal, "comparative studies on adsorptive removal of chromium from contaminated water using different adsorbents", indian journal of chemical technology ,issn:0971-457x,vol. 10 no.1, jan.2003,pp.72-78activated carbon, http://www. activated carbon india. com/powdered, granulated, ac.htm. 5. r.f.p.m. moreira & m.g. peruch and n.c. kuhnen, brazil, "adsorption of textile dyes on alumina", brazil j. chem. eng. vol. 15, no. 1 san paulo, (1998). 6. prof. dr. ing. m.jekel, dr. ing. silke karcher, "sorption and oxidation processes for the removal of reactive dyes in partial streams and mixed wastewaters", german research council (gfg), corporative research center s fb 193, http//itu107.ut.tuberlin.de/wrh/english/research/proold/ anion. htm, (2004). 7. hayder m.ah.m.sc. thesis, "reduction of organic content in wastewater by adsorption onto activated carbon",env.eng.dept. collage of eng. univ. of baghdad,(1996). 8. maisa m. ar. thesis,"adsorption of btx aromatics from reformate by 13x molecular sieve",(2003). 9. ibtehal k. sh. ph.d. thesis ,"study of textile industrial wastewater treatment and recycling process", chem. eng. dept. collage of eng. univ. of baghdad,(2002). 10. liangs s., "dual practice diffusion model in fixed bed", aice env. prog., (1983). 11. sorption with activated carbon, www.cee.vt.edu/program-areas/ environmental/teach/ gwprimer/group23/sorp-ac. 12. m. bonnevie-svendsen, "sorption and filtration methods for gas and water purification", noordhoffleyden, pp(160), 1975. http://www/ http://www.cee.vt.edu/program-areas/ iraqi journal of chemical and petroleum engineering vol.16 no.3 (september 2015) 19 issn: 1997-4884 problems of heavy oil transportation in pipelines and reduction of high viscosity ayad a. abdulrazak, mohammed al-khatieb * and haidar a. faris, petroleum engineering department– university of baghdad * ministry of oil-oil pipelines company abstract drag has long been identified as the main reason for the loss of energy in fluid transmission like pipelines and other similar transportation channels. the main contributor to this drag is the viscosity as well as friction against the pipe walls, which will results in more pumping power consumption. the aim in this study was first to understand the role of additives in the viscosity reduction and secondly to evaluate the drag reduction efficiency when blending with different solvents. this research investigated flow increase (%fi) in heavy oil at different flow rates (2 to 10 m3/hr) in two pipes (0.0381 m & 0.0508 m) id by using different additives (toluene and naphtha) with different concentrations (2, 4, 6, 8 and 10) wt. % at 35ᵒ c. the results of this study showed the following:  increasing values of dr% and fi% for all drag reducing agents with heavy oil. increasing values of dr% with increasing of reynolds number, fluid velocity and additive concentration.  with the larger pipe diameter, performances of drag reduction occur is much better than smaller pipe diameter.  the additives (toluene and naphtha) reduce the high viscosity of used heavy oil.  naphtha is more efficient as viscosity reducer than toluene. finally, all these results help the understanding of the flow properties of heavy oils and aim to contribute to the improvement of their transport. key words: heavy oil, drag reduction. introduction cost saving is one of the most essential concerns in any industry. one of the key to the present concern is by cutting down on the power consumption. fluids transportation in pipelines and other similar transportation channels tends to consume loads of power for the reason that in moving fluid, energy will be dissipated due to mainly frictional drag. drag reduction is a flow phenomenon in which a reduction in turbulent friction occurs. since the early forties, drag reduction has become an increasing interest in science and technical applications. power saving, is the major headline for many investigations that deals with drag reduction [1]. iraqi journal of chemical and petroleum engineering university of baghdad college of engineering problems of heavy oil transportation in pipelines and reduction of high viscosity 2 ijcpe vol.16 no.3 (sept. 2015) -available online at: www.iasj.net one of the modern techniques in drag reduction is by the addition of different quantities of chemical additives (such as polymer, surfactant or fiber ) to liquids transported in pipelines. that in some cases, it is necessary to increase the transported liquid flow rate in built pipelines to avoid any extra costs and time spend on building new pipelines to have the same flow improvement needed. another types of chemical additives are solvent, which have the ability to dilute heavy oil transported in pipelines, but requires a large investment for the installation of an additional return pipeline. the objectives of this study are: 1to study the effect of additive, quantity and type of solvent on the flow in pipelines. 2to study the effect of fluid flow rate on transportation in pipeline 3to study the influence of solvents that reduced the viscosity of heavy oil with significance to their functions in the drag reduction in pipelines. literature review drag reduction is a phenomenon in which the friction of a liquid flowing in a duct in turbulent flow is decreased by using small amount of additives. this is beneficial because it can decrease pumping energy requirements. some current applications where drag reduction has been applied include oil transmission pipelines, district heating and cooling systems. different types of additives can be used in these systems and include surfactants, fibers, aluminium disoaps, and polymers. drag reducing additives are effective because they reduce the turbulent friction of a solution. these results will decrease the pressure drop across a length of conduit and likewise reduce the energy required to transport the liquid [2]. 1drag reduction by using surfactants davis et. al. investigated experimentally the effects of mixtures of cationic surfactant on their drag reduction and rheological behaviour. cationic alkyl tri methyl quaternary ammonium surfactants with alky chain length of c12 to c22 were mixed at different molar ratios. the drag reduction tests showed that by adding 10% mole of c12, the effective drag reduction temperature range expands to 40-120ºc, compared with 80-130ºc with only c22 surfactant. thus mixing cationic surfactants with different alkyl chain lengths is an effective way of tuning the drag reduction temperature range. the experimental results showed in micrographs a thread-like miceller network for surfactant solutions in the drag reducing temperature range while vesicles were the dominant microstructures at nondrag reducing temperatures and this supports the widely believed hypothesis that thread-like micelle network are necessary for the surfactant solution to be drag reducing[3]. abdul-hakeem tested different types of surfactants, three anionic surfactants plus one non-ionic surfactant as drag reducers in turbulent pipe flow of iraqi crude oil within three pipe diameters of 0.5, 1, and 3 inch i.d. the investigator concluded that the percentage drag reduction (%dr) increasesby increasing the surfactant concentration (within certain limits), solution flow rate and pipe diameter. maximum percentage drag reduction of 56.5% was achieved at concentration of 200 ppm sdbs surfactant. finally, the drag reducing mechanism was explained by the interaction of surfactant micelles with the crude oil, ayad a. abdulrazak, mohammed al-khatieb and haidar a. faris, -available online at: www.iasj.net ijcpe vol.16 no.3 (sept. 2015) 3 which allows the turbulence to be suppressed [4]. hussein, h. studied the effectiveness of two surfactants (sodium dodecyl benzene sulfonate (sdbs) and sodium lauryl sulfate (sls)) in crude oil by using a closed loop system for three pipes of different diameter (0.75, 1 and 1.5 inch) with length 2m for each and he used three different temperatures (30º, 40º and 50°c). the concentrations of both surfactants used are ranging between 50 to 300 ppm. he found that the final results showed that the highest drag reduction (%dr) was 23.67% (flow increase percentage was 16%). this value is obtained when 200 ppm sdbs is added at 30°c [5]. 2drag reduction by using polymers motier used polymeric drag reducing agents to facilitate the pipeline transportation of crude oil and some refinery products (reducing the frictional loss associated with turbulent flow of liquids). motier obtained the best performance with gasoline and fuel oil in his experiments. the great effectiveness has been found in the low viscosity kirkuk crude oil. the variability in performance was a function of the viscosity of crude [6]. shao and lin studied the mechanism of drag reduction by polymer (polyacrylamide) additives. the researchers concluded that the visualization of mixing layer shows that the addition of polymer will enhance coherent structure. the measurements of the turbulent intensities and reynolds stresses by lda show that polymer additives do not simply suppress the turbulent fluctuation as they expected. in pipe flow, the axial turbulence intensity is increased while the radial turbulence intensity is decreased. this means that the turbulence structure is changed rather than suppressed [7]. taegg et al. studied the maximum drag reduction (mdr) in a turbulent channel flow by polymer additives using numerical simulation in aqueous solution [8, 9]. aly s. asaad studied the effectiveness of two polymers (polyisobutylene(pib) ) and (styrene styrenebutediene rubber (sbr) ) and in kerosene by using a closed loop system for four pipes; 1,1.5 inch i.d. made of carbon steel and 1, 1.5 inch i.d. made of galvanized iron. a gradual increase of 4 percentage drag-reduction was observed with increasing the polymer concentration and velocity. the 1.5 inch i.d. carbon steel pipeline at 3m long (test section) shows higher drag reduction compared to other pipes at constant velocities [10]. 3viscosity reduction blending with a less-viscous hydrocarbon such as condensate, naphtha, kerosene or light crudes it's called dilution. however, in order to attain acceptable limits for transport, a fraction as high as 30% of diluents by volume is necessary and implies large pipeline capacity. problems may also arise with regard to diluents availability [11]. dilution could be a solution for heavy oil, but requires a large investment for the installation of an additional return pipeline. anhorn et al. studied methyl tertbuty ether (mtbe) and tert-amyl methyl ether (tame) in laboratory experiments as alternative thinners for heavy oils [12]. henaut,i. et al. used simple organic solvents (toluene, hept ne…) which are not representative of complex heavy crude oils(from 0 to 20% in weight). all results help the understanding of the flow properties of heavy crude oils and aim to contribute to the improvement of their transport [13]. problems of heavy oil transportation in pipelines and reduction of high viscosity 4 ijcpe vol.16 no.3 (sept. 2015) -available online at: www.iasj.net argillier,j.f. et al. used different low viscosity hydrocarbons as diluents, in particular naphtha, kerosene. in a second part of the study different alcohols are used also for blending with heavy oil. concerning tests with diluents, 4 dilution rates (5, 10, 15 and 20% in weight) and 5 temperatures (3, 20, 40, 60 and 80°c) have been tested for each diluent [14]. finally, in this work flow with reynold’s number lower th n 4000 is regarded as laminar flow. with heavy oil viscosity in the range of 100-10000 cp, it can readily be shown that pipe flow will be laminar using any economically viable pipe diameter. the reynold’s numbers for pipe diameters ranging between 1-30 inches, using common heavy oil values for density, viscosity and flow velocity as shown in figure(1)[15]. fig. 1, reynolds number vs. pipe di meter [15] (ρ = 975 kg/m3, u = 1 m/s, μ = 500 cp) description of circulating flow loop system the description of main parts of the flow system as shown in figure (2). it represents the flow system apparatus used in the present work, which consist of reservoir tank of solution, pump, flow meter, pipes, valves, pressure transmitter, digital screen, chiller and digital thermometers. fig. 2, schematic diagram of flow system ayad a. abdulrazak, mohammed al-khatieb and haidar a. faris, -available online at: www.iasj.net ijcpe vol.16 no.3 (sept. 2015) 5 material used 1liquid the used heavy oil was taken from al-doura refinery with physical properties as given in table (1). table 1, physical properties of heavy oil temperature °c specific gravity kinematic viscosity c.st 35 0.965 394.00 2solvents toluene and naphtha were used as drag reducing agents and to dilute the viscosity with concentration 2, 4, 6, 8 and 10 % by weight. solvents were provided by al-doura refinery. experimental procedure 1the reservoir was filled with 75 liter of corresponding fluid heavy oil. 2the heavy oil is permitted to flow in only one pipe. the flow rate of solution was controlled by bypass section until this rate reached a specific value. 3the pressure drop is read by transmitter which is connected with the digital screen. 4steps 2 and 3 are repeated with different flow rates. keeping in mind that this operation is carried out at constant temperature. 5the above steps are redone but with the different additives of solvents to the heavy oil. 6steps 2 to 5 are repeated for the other pipe. 7using different solvent types and concentrations, the above procedure is redone for the sake of observing the effect of these parameters on pressure drop. results and discussion  maximum dr% of 38.78% and 31.85 % were obtained using heavy oil containing 10% wt of naphtha flowing in pipes of 0.0508m and 0.0381 m i.d. at 35°c respectively.  the maximum volumetric flow rates in (0.0508 and 0.0381) m i.d. pipes were 10 m3/hr. the naphtha has a large stability than toluene. this may be attributed to the chemical structure and its resistance to the shear forces which governs the effectiveness of the solvent used as drag reducer. the effect of the used additives (toluene and naphtha) on drag reduction as shown in figures (3-4). fig. 3, effect of re on %dr in heavy oil flowing through 0.0508 m i.d. pipe fig. 4, effect of re on %dr in heavy oil flowing through 0.0381 m i.d. pipe problems of heavy oil transportation in pipelines and reduction of high viscosity 6 ijcpe vol.16 no.3 (sept. 2015) -available online at: www.iasj.net the effect of solution of velocity (v) on the percentage drag reduction (%dr) in term of dimensionless group (re) was done which showed the drag reduction percentage increases with increasing fluid velocity. increasing the fluid velocity means increasing the reynolds number inside the pipe, this will provide a better media to the drag reducer to be more effective. the behaviour of increasing %dr with velocity of fluid may be explained due to relation between degree of reynolds number controlled by the solution velocity and the additive effectiveness as shown in figures (5-8). fig. 5, effect of reynolds number on percentage drag reduction for toluene in heavy oil flowing through 0.0381 m i.d. pipe fig. 6, effect of reynolds number on percentage drag reduction for toluene in heavy oil flowing through 0.0508 m i.d. pipe fig. 7, effect of reynolds number on percentage drag reduction for naphtha in heavy oil flowing through 0.0381 m i.d. pipe fig. 8, effect of reynolds number on percentage drag reduction for naphtha in heavy oil flowing through 0.0508 m i.d. pipe %dr and %fi increase with increasing the additive concentration for toluene or naphtha at certain value of reynolds number. the increment in %dr is ascribed to increases of associated additive molecules in the process of drag reduction. also, it show that there is not a limit value of concentration after which no further drag reduction occurs within additives concentration (2–10 %wt) for toluene and naphtha as shown in figures(9-12). ayad a. abdulrazak, mohammed al-khatieb and haidar a. faris, -available online at: www.iasj.net ijcpe vol.16 no.3 (sept. 2015) 7 fig.9, effect of concentration on percentage drag reduction for toluene in heavy oil flowing through 0.0381 m i.d. pipe fig. 10, effect of concentration on percentage drag reduction for toluene in heavy oil flowing through 0.0508 m i.d. pipe fig.11, effect of concentration on percentage drag reduction for naphtha in heavy oil flowing through 0.0381 m i.d. pipe fig. 12, effect of concentration on percentage drag reduction for naphtha in heavy oil flowing through 0.0508 m i.d. pipe the effect of concentration of the additive types on the viscosity reduction the used additives affect the physical properties of present used heavy oil, while the viscosity was reduced which indicated that we treated high viscosity and diluted heavy oil after addition as shown in figure(13) fig. 13, effect of different concentration on viscosity for naphtha and toluene in heavy oil problems of heavy oil transportation in pipelines and reduction of high viscosity 8 ijcpe vol.16 no.3 (sept. 2015) -available online at: www.iasj.net conclusions 1the additives (toluene and naphtha) were found to be effective drag reducing agents when used with heavy oil. 2drag reduction percent or flow increase percent are increased with increasing velocity of solution, increasing concentration of additives and decreased temperature. 3maximum %dr of 38.78% was obtained using heavy oil containing 10% wt of naphtha flowing in pipes of 0.0508 m i.d. at 35°c at flow rate 10 m3/hr. 4the additives (toluene and naphtha) diluted the high viscosity of used heavy oil. 5the drag reduction occurs because of the interaction of the additives with heavy oil due to increasing the intermolecular distance within the oil and decreases the viscosity and density. 6the used additives affect the physical properties of present used heavy oil, while the viscosity was reduced which indicated that we treated high viscosity. nomenclature c: solvent concentration %dr: percentage drag reduction %fi: percentage flow increase re: reynolds number (vd/) t: temperature %wt.: percentage weight references 1sahar, a. al-ramadhani, "drag force reduction of flowing (kerosene & gas oil) using surfactants in carbon steel and pvcm pipes", ph. d. thesis, chem. eng. dept, university of technology, (2006). 2zakin, j. l. et al., "rheology of drag reducing surfactant systems", thesis in drag reduction by katie severson, (2005). 3davis, h. t. zhiging, l., lu, c. c., bin, l., yi, z., scriven, l. e., talmon, y. and zakin, j. l.,"experimental studies on drag reduction and rhology of mixed cationic surfactants 13 with different alkyl chain length", real. acta, 39, pp 354-359, (2000). 4abdulhakeem, a. r.,"optimizing viscous flow in pipes through improving flow conditions and chemical injections", ph. d. thesis, pet. eng. dept, university of baghdad, (2000). 5hussein, h.h., “l bor tory study of improving the transportation efficiency of oil in pipes”, . sc. thesis, pet. eng. dept., university of baghdad (2007). 6motier j.f., "polymeric drag reducers", pipeline and gas j., 212 (6), june, pp. 32–37 (1985). 7shao x. and lin j., "experimental research on drag reduction by polymer additives", www.fluidpower.net (1997). 8taegee m., jung y.y., haecheon c. and daniel d.j., "drag reduction by polymer additives in a turbulent channel flow", j. fluid mech., 486, pp. 213–238 (2003). 9taegee m., jung y.y. and haecheon c., "maximum drag reduction in a turbulent channel flow by polymer additives", j. fluid mech., 492, pp. 91–100 (2003). 10 ly s. as d , “reduction of friction in fluid transport by using polymers”, . sc. thesis, pet. eng. dept., university of baghdad (2009). 11crandall, g.r. and wise, t.h. (1984) availability of diluent may inhibit heavy oil exports. can. pet., 25, 37-40 12anhorn, j.l. and badakhshan, a. (1994) heavy oil oxygenates ayad a. abdulrazak, mohammed al-khatieb and haidar a. faris, -available online at: www.iasj.net ijcpe vol.16 no.3 (sept. 2015) 9 blends and viscosity models. fuel: guildford, 73, 9, 1499-1503. 13hénaut, i., barré, l., argillier, j.f., brucy, f. and bouchard, r. (2001) rheological and structural properties of heavy crude oils in relation with their asphaltenes content. spe 65020. 14argillier, j.f., barré, l., brucy, f., dournaux, j.l., hénaut, i. and bouchard, r. (2001) influence of asphaltenes content and dilution on heavy oil rheology. spe 69711. 15fabian b., "heavy oil production technology challenges and the effect of nano sized metals on the viscosity of heavy oil ", department of petroleum engineering and applied geophysics, norwegian university,(2013). ijcpe vol.10 no.2 (june 2009) 37 iraqi journal of chemical and petroleum engineering vol.10 no.2 (june 2009) 37-41 issn: 1997-4884 application of neural network in the identification of the cumulative production from ab unit in main pays reservoir of south rumaila oil field. * mohammed s.al jawad and ** ghazwan n s jreou * petroleum engineering department college of engineering university of baghdad – iraq ** material engineering department – collage of engineering – university of kufa abstract a common field development task is the object of the present research by specifying the best location of new horizontal re-entry wells within ab unit of south rumaila oil field. one of the key parameters in the success of a new well is the well location in the reservoir, especially when there are several wells are planned to be drilled from the existing wells. this paper demonstrates an application of neural network with reservoir simulation technique as decision tool. a fully trained predictive artificial feed forward neural network (ffnnw) with efficient selection of horizontal re-entry wells location in ab unit has been carried out with maintaining a reasonable accuracy. sets of available input data were collected from the exploited grids and used in the training and testing of the used network. a comparison between the calculated and observed cumulative oil production has been carried out through the testing steps of the constructed ann, an absolute average percentage error of the used network was reached to 4.044%, and this is consider to be an acceptable limit within engineering applications, in addition to that, a good behavior was reached with (ffnnw) and suitable re-entry wells location were identified according to the reservoir configuration (pressure and saturation distribution) output from srf simulation model at the end of 2005. keywords:. horizontal re-entry well, neural network application, cumulative production. introduction the need of reservoir quantification and development can be achieved by more accurately reservoir performance with rigorous and complex full field reservoir models that is become basic requirement. increasing of understanding and certainty of the information derived from advanced field scale simulation contributes the decision process reliability in comparison to the large capital expenditures required for the reservoir developments. a variety of development options are under consideration by the reservoirs and field development directorate in south oil company that planning to execute. one of these development planning is to introduce a proposing horizontal re-entry wells in ab production unit in the main pay reservoir. but before introducing the suggested wells, a full field reservoir study (1) has been carried out by constructed a srf simulation model by using of simbest ii simulator, that covered the time period spanned from 1954 to the end of 2005 according to the available information comprising all of the important data that related to the history matching of the concerning reservoir. the most important outputs for our reservoir unit concern are both of the pressure and saturation grid distribution for ab unit. figures (1-2) show these output maps, and then a feed forward neural network has been used as decision making tool to investigate how much cumulative oil production can be gained from university of baghdad college of engineering iraqi journal of chemical and petroleum engineering application of neural network in the identification of the cumulative production from ab unit in main pays reservoir of south rumaila oil field. ijcpe vol.10 no.2 (june 2009) 38 unexploited ab grid unit, then inspect their adaptability with introducing re-entry horizontal well. figures (3-4) present these elected and unexploited grid areas. review of the field concern the rumaila oil field is located in south of iraq, 50 km west of basra and 30 km to the west of the zubair field. the northern part of the rumaila is a marsh land and it plunges gradually below hor al-hammar lake. the south rumaila oil field extended from the south of the north rumaila oil field to the southern boarder of iraq. the dimensions of south rumaila oil field are about 38 km long and 14 km a wide. the field is associated with large gentle anticline fold of submeridional trend; dip angles on the flanks do not exceed 3○ whereas in the crestal parts they are about 1○. figure (5) shows the geographical location of the rumaila field. rumaila structure is consisting of three domes namely southern, northern domes. they are separated by small structural saddles. accordingly, the field which is geologically and hydrodynamically uniform is subdivided into two parts, namely north rumaila and south rumaila. the south rumaila oil field / main pay reservoir is mainly composed of sandstone with some of the interbeded shale and siltstone. in general, the reservoir has very good properties. also the main pay consists of five production units according to the differences between the porosity and the permeability. geographical and petrophysical description of these production units are presented in the reference (1). the south rumaila field is surrounded by a large aquifer (2) and the predominate production driving force is the natural water drive which is very active as driving force and contribute to 90% of the production. neural network application inspection, identification and prediction reservoir characteristics are the main application of ann in petroleum engineering in addition to another application (3,4). the present research deals with the ann as a decision tool when prediction cumulative oil production. the property of a reservoir is controlled by many nonlinear parameters. a reservoir is usually made up of layered sedimentary rocks, which were defined after a long period of sedimentation and millions of years of diagenesis as well as structural evolution. these sedimentation, diagenesis and structural evolution processes are dominated by a series of nonlinear timevarying dynamic systems existing in the geological history. each layer or zone in a layered reservoir, corresponding to a particular geological period in the geological history, is usually controlled simultaneously by more than one non-linear dynamic system (time varying or time invariant) which have quite different controlling parameters from those for another layer or zone. in addition to the geologic parameters (5), reservoir modeling and characterization always involve a high degree of uncertainty due to the following factors: 1. experimental errors resulted from different procedures or the equipment used 2. lack of information 3. disagreement between experts 4. poor identification of the model attributes 5. inappropriate definitions of the problem and their domain 6. errors involved in the translation from natural language to a formal or machine language. because of these factors, a powerful tool is required to deal with the fuzziness, incompleteness, poorly defined nonlinear systems, and uncertainties that exist in reservoir studies. neural networks are well suited for these problems. according to jacek m. zurada (1992) (6), anns have essential qualities in:  learning  association ability  real-time capability  self-organization  robustness against noise  ability to generalize. in the present research, the above qualities were reflected by the results of the testing and simulation steps, where a noise data were used and recognized by the neural. thus it seems that neural networks are quite suitable to solve reservoir problems. the application of neural networks to reservoir studies (7) has become a hot topic in today's oil and gas industry. in recent years, anns have been successfully used in various aspects of reservoir studies, such as geology, geophysics, drilling and completion, formation evaluation, production and simulation and reservoir engineering (8-11). ann are developed by creating artificial neurons, which are simple processing elements (pe) massively interconnected in order to mimic a small portion of the serialand parallel-information processing ability of the biological neural network. there are many different types of ann, each of which has different strengths particular to its applications. the abilities of different networks can be related to their structure, dynamics, and learning methods. ann can be used for pattern recognition, signal filtering, data segmentation, and so on. they offer the advantages of learning from examples, self-organization, fast data processing and ease of insertion into existing and newly developed systems. ann provides a powerful tool to perform nonlinear, multidimensional interpolations. this feature of ann makes it possible to capture the existing nonlinear mohammed s.al jawad and ghazwan n s jreou ijcpe vol.10 no.2 (june 2009) 39 relationships that are most of the time not well understood between the input and output parameters. thus ann can be effectively used to implicitly incorporate the controlling mechanisms and parameters into the models which are developed for. the multilayer ffnnw (12) is an important ann architecture. typically, this network consists of an input layer, one or more hidden layers and one output layer figure (6) shows the schematic at each node, a function (activation function) is applied to the node input. usually, the activation functions of the nodes at each layer are the same. the input layer activation function is usually the identity function, while the hidden layer activation function is usually non-linear for nonlinear systems and that of the output layer may be linear or nonlinear. the following are briefly description of the some of activation function that are using within neural networks ( 12 ) function name diagram mathematical expression 1tan sigmoid tansig (n) =   1exp1 2 2   n 2log sigmoid logsig (n)=  nexp 1 1 3radial basis rad bas (n) =  )( 2 n exp  4sat lines satlines (n) = -1 if n<= -1 1 if n >= 1 n -1 <= n <= 1 5pure line purelin (n) = n ijcpe vol.10 no.2 (june 2009) a frequently used network is the multi-layer feed forward network that is trained by the back-propagation (bp) learning algorithm, which is extensively used in this work. bp networks typically operate in two modes, a learning mode and a testing mode. in the learning or training mode, ann modifies its internal representation by changing the values of its weights in an attempt to improve the required outputs. in the testing or recall mode, the network is fed new inputs and utilizes the representation it had previously learned to generate associated outputs without changing the values of its weights. if this is done properly, superior performance and more accurate forecasts can be achieved over rule based technical analysis methods. used of ann to identify cumulative production.the neural network used in this research is the standard back propagation feed forward neural network (ffnnw) that was developed through the back propagation training algorithm which allow the ann to learn it by its self according to the input data sets of input and output results. this kind of networks classified as supervised network that required training data sets with known inputs and outputs. the used ann was developed through the back propagation training of feed forward neural network, which allow the ann to predict the cumulative production for ab unit grids that were un exploited (virgin grids). once the network has learned by exposed it to such information in the training phase, a testing phase has been applied to the network for verification which coverage a range of input data sets of input parameters with different variety from training range. it is important to note that although the user has the desired output of the test set; it has seen by the network with some of difference. this ensures the integrity and robustness of the trained network. the first step of applying the neural network is how to process the input data sets by coding them, because of their variety in values range. inorder to prevent the noise effect that disturbs the learning of the network or it may prevent the network to reach its goal at all. the second step is the training network inorder to help the network to adjust the weights among it’s neurons or processing elements (supervised training), section a of table (1) presents input data sets for this step, whenever the ann is good trained for a specific reservoir configuration, it forms a fast predictive tool for checking the location of the new wells in the reservoir, therefore this step has taken more time than other steps. the connection elements (weights) are initialized with random numbers and are iteratively updated using the algorithm until the total error between calculated and known outputs of the entire training pattern is minimizing as indicated by the figure (7) of the used network. the third step is testing of the trained network inorder to check the network validity or in other words, how is the generality of neural network in the problem space. so it is necessary to expose the network to sufficient data sets for both processes learning and adjusting. new sets of input data will be provided to the neural network and the difference between the actual and real output at this step is check. high error rate mean the network didn’t learn the general solution of the problem, and then further learning will be needed. section b of table (1) presents the input data sets and output results. the fourth step that followed with the trained and tested neural network is to simulate the new un exploiting grid areas with ab unit to check how much oil can be gained. according to the training step, good and encourage results were obtained. table (2) shows these data input and output sets for the neural network simulation step. results and discussion it is clear from the output trend behavior of the used ffnnw through the training phase as shown in figure (7), the network has very good training and reaching its goal where the calculated difference is specify. this trend was reached according to the powerful training algorithm used with the network which is an advanced version of standard gradient descent algorithm that introduces momentum and dynamic learning factor as good factors to enhance the behavior of the algorithm according to the following weight adaptation equation : )(*** )()1( dx dperf mclrwmcw tt   where:   )1(tw the new weight adjustment  )(tw the previous weight adjustment mc = momentum constant (d perf /dx) = derivative of performance with respect to weight and bias. lr = learning factor. learning factor will change as following: lr (t+1) =         declrtlr inclrtlr )( )( where : inc. = increase factor (1.05 ratio), if performance increase toward goal. dec. = decreasing factor (0.7 ratio), if performance increase more than max performance. mohammed s.al jawad and ghazwan n s jreou ijcpe vol.10 no.2 (june 2009) 41 in addition to that , the following table explain the structure of the constructed ann. for more details on can refer to reference ( 12 ). the absolute average percentage error indicated by the used network is 4.044 %. in respect to the results of simulation phase of the used network, which had been trained and tested according to the data available and included in table (1) previously, it is note that the output column (cumulative oil production) represents the main objective of the research in the application of selected network in the present research. also it is note that there is a clear trend in the results, while here is a disparity among the studied grids location which are called virgin grids. these grids areas unused or un exploited even by vertical wells that were operating in the concerning field , therefore these grids still reserve with high oil saturation that can exploited by either vertical or horizontal wells according to the future development planes by the reservoir and field development directorate in south oil company. in addition to that the method was easy and accurate in the investigation of those grid areas in the field under study, also it is good way of identification for new field locations before switching to reservoir simulator in comparison with the conventional method in the field of inspection and prediction manner according to the type of relationship between input variables in calculation involved. the calculated error percentage by this application falling with the acceptable range that is indicating good results obtain and give us more convenience when use this application in ann simulation phase. also this is good crediting for calling this method rather than using of prolong regression or convention calculations. conclusions 1. artificial neural network models can provide a better description of relationships and dependencies among datasets; also it has also proven to be a valuable tool in cases where adequate engineering data are not available but where a large amount of historical data can be acquired. 2. best behavior was obtained and reaching to the desired goal with 178 epochs after many trials during the training of the used network. 3. good indication were obtained were whenever horizontal re-entry wells location identified by the used (ffnnw). nomenclature ffnnw = feed forward neural network ann = artificial neural network soc = south oil company srf = south rumail field kx = horizontal permeability (md) h = layer thickness (ft) sw = water saturation (percentage) p = pressure (pisa). references 1. jreou, g.n. “a study for increasing productivity from ab formation unit in southern oil field by designing a horizontal wells network. ثامر عباس غضبان وبان جعفر حمزي .2 انمكمه انرئيسي ، / سرد انتاريخ األوتاجي نحقم انرميهً انجىوبي 1983بغداد أيهول 3. mohaghegh, s. “ neural network : what it can do for petroleum engineering”, spe 29219 – pa 1995 4. mohaghegh, s. and amer, s. “artificial neural network as a valuble tool for petroleum engineering”, spe 29220. 5. yuqi, du. et.al, “obtain an optimum artificial neural network model for reservoir studies”; spe 84445-ms, 2003. 6. ahmed, t. et.al. “ application of neural network parameters prediction in reservoir characterization and simulation”, spe 38985 – ms 1997 7. introduction to artificial neural systems, zurada, jacek m., west publishing company, 1992. 8. al thuwaini, j.s."how data driven modelling methods like neural networks can help to integrate different types of data into reservoir managements”; spe 68163-ms 2001. input layer 4 hidden layer output layer 1 learning factor start with momentum factor 7% epoches 200 acceptable goal error 1e-04 application of neural network in the identification of the cumulative production from ab unit in main pays reservoir of south rumaila oil field. ijcpe vol.10 no.2 (june 2009) 42 9. centilmen, a. et.al.” application of neural network in multi well field development”; spe 56433-ms, 1999. 10. saputelli, l.et.al, “a critical overview of artificial neural network application in the context of continuous oil field optimization”, spe 77703-ms, 2002. 11. leonid.s.et.al “ior evaluation and applicability are screening using artificial neural networks”; spe 59308-ms, 2000. 12. matlab software package user manual, version 7. mohammed s.al jawad and ghazwan n s jreou ijcpe vol.10 no.2 (june 2009) 43 figure (1) – final pressure distribution of ab unit at the end of 2005, (psia) figure (2) – water saturation distribution of ab unit at the end of 2005 application of neural network in the identification of the cumulative production from ab unit in main pays reservoir of south rumaila oil field. ijcpe vol.10 no.2 (june 2009) 44 figure (3) demonstration of the present exploited grids areas mohammed s.al jawad and ghazwan n s jreou ijcpe vol.10 no.2 (june 2009) 45 application of neural network in the identification of the cumulative production from ab unit in main pays reservoir of south rumaila oil field. ijcpe vol.10 no.2 (june 2009) 46 figure (4)demons. of different grids area within south rumaila oil field figure (5) – gographical location of rumaila field figure (6) basic structure for multilayer perceptron network figure (7) ffnnw training performance ( training stopped at 178 epochs ) 33 iraqi journal of chemical and petroleum engineering vol.11 no.4 (december 2010) 3345 issn: 12010-4884 fluid catalytic cracking of petroleum fraction (vacuum gas oil) to produce gasoline abdul halim a-k mohammed and karim khalifa esgair chemical engineering department, college of engineering, baghdad university abstract in this work, fluid catalytic cracking of vacuum gas oil to produce gasoline over prepared faujasite type y zeolite was investigated using experimental laboratory plant scale of fluidized bed reactor. the catalytic activity of prepared faujasite type nay, nanh4y and nahy zeolites was investigated. the cracking process was carried out in the temperature range 440 to 500 o c, weight hourly space velocity (whsv) range 10 to 25 h -1 ,and atmospheric pressure . the catalytic activities of the prepared faujasite type nay , nanh4y and nahy zeolites were determined in terms of vacuum gas oil (vgo) conversion, and gasoline yield . the conversion at 500 o c and whsv10 hr -1 by using faujasite type nay, nanh4y and nahy zeolite were 50.2%, 64.1% and 69.5wt% respectively. the gasoline yield using the same operating conditions were 24.8%, 30.5% and 36.8wt% respectively. gas chromatographic analysis of produced gasoline shows that the paraffin, olefin, and aromatic content change considerably with the end point temperature of gasoline fraction. keywords : fluid catalytic cracking ; gasoline production ; vacuum gasoil cracking introduction the catalytic cracking unit is the most important conversion facility in a modern refinery. this process consists of the scission of the hydrocarbon c–c bonds present in the feedstock (usually vacuum gas oils or residues) in order to obtain gasoline, light alkenes or other low molecular weight hydrocarbons [1]. this process produces about 45% of the total gasoline pool either directly or indirectly [2]. catalytic cracking was truly revolutionized in the early 1960s with the advent of zeolite containing fluid cracking catalysts. catalyst activities were raised by an order of magnitude and units needed to be redesigned to take full advantage of the new catalyst technology [3]. these design changes iraqi journal of chemical and petroleum engineering university of baghdad college of engineering fluid catalytic cracking of petroleum fraction (vacuum gas oil) to produce gasoline 34 ijcpe vol.11 no.4 (september 2010) included the elimination of reactor dense beds and the use of the feed riser as the sole conversion vessel. recycle was greatly reduced and replaced with more fresh feed. it was found that coke left on the regenerated catalyst impaired the catalyst activity and selectivity and the average carbons on regenerated catalyst were reduced [4]. the two main components of cracking catalysts are the zeolite y and the matrix. the main functions of the matrix are to pre-crack large molecules and adsorb ni and v preferentially in order to protect the zeolite y of the catalyst particle [5]. most studies in fluidized catalytic cracking have focused on zeolite y, as this is still the dominant zeolite used in fcc. besides the acid properties of this zeolite, the unique pore architecture of y zeolite is ideal for cracking gas oil components into gasoline molecules [6]. in this respect, y zeolites dealuminated by steaming (usy) create a secondary porosity formed during the partial destruction of the zeolite framework and forming mesopores which facilitate diffusion of larger molecules into the zeolitic channels. the obtained usy type zeolites show, a much better hydrothermal stability [7]. this zeolite can significantly improve the octane number of gasoline in catalytic cracking. addition of a few percent zsm-5 to a conventional fcc catalyst gives an equivalent octane number increase [8].the light olefins for petrochemicals are a valuable product, often exceeding the revenue obtained for transportation fuels. as a consequence, distinctive processes for making much larger amounts of propylene than a normal fcc unit have been developed. the deep catalytic cracking process was the first commercial scale process that was designed to maximize propylene. specially formulated catalysts, more severe process conditions and equipment made to handle the unique product distribution are all components of this technology [9]. a modified deep catalytic cracking (dcc) process has been offered by sinopec, termed as catalytic pyrolysis process (cpp), in which vacuum gas oils and atmospheric residues are converted to produce all petrochemical products, i.e. ethylene, propylene, butenes, and aromatics. this process is really a substitute for a steam cracking furnace in an ethylene plant. it allows the operator to use cheaper feedstocks and vary the ratio of ethylene to propylene over a wider range than is possible with only thermal cracking [10]. the aim of the present work is to design and construct a fluid catalytic cracking unit to study the performance of the prepared catalyst to produce gasoline from vacuum gas oil. the effect of the gasoline end point on the produced gasoline composition was also investigated. experimental feedstock and catalyst vacuum gas oil with boiling range 265 o c to 400 o c supplied from vacuum distillation unit of al-duara refinery was used as a raw material for fluidized catalytic cracking process. the cracking catalyst( faujasite type y zeolite catalyst ) was prepared from locally available kaolin. the properties of catalyst type nay and vacuum gas oil are reported in table 1 and 2, respectively . the prepared faujasite type nay zeolite was modified by exchanging sodium ion with ammonium ion to obtain nanh4yzeolite . hydrogen -form zeolite catalyst prepared by calcinations na nh4-y. table 1 prepared catalyst properties . specific area (m 2 /g) 360 pore volume (cm 3 /g) 0.39 silica to alumina mole ratio 3.85 unit cell size (ucs) (å ) 24.73 abdul halim a-k mohammed and karim khalifa esgair ijcpe vol.11 no.4 (september 2010) 35 table 2 properties of vacuum gas oil. specific gravity at 60/60 o f 0.8739 pour point, o c 5 viscosity at 37.8 o c,ssu 51.22 viscosity at 98.8 o c,ssu 33.54 aniline point , o c 70 molecular weight 278 refractive index at 20 o c 1.4875 k uop -factor 11.70 kw-factor 11.67 astm distillation(d-86), o c ibp 265 10% 281 30% 304 50% 316 70% 334 90% 381 fbp 400 fcc experiment the fcc experiments were carried out at temperature range 440 to 500 o c, whsv range 10 to 25 h -1 ,catalyst particle size between75 to 150 micrometer, and atmospheric pressure using prepared catalyst nay form,nh4yform,and nahy form. fig 1 represents the schematic flow diagram of the fluidized catalytic cracking system. analytical method catalytic cracking products include gases c1–c5, and gasoline were analyzed by gas chromatography method. gas chromatograph agilent technologies 6890n located in alduara refinery. this analysis was used to measure the volume percentage of components in the gas product the equation of state for ideal gases converts the volume data to mass . this gc column type was porapak q, length 1.8m ,diameter 3mm ,and mesh 80-100 was used to measure the gas product from fluidized catalytic cracking unit. the operating condition of gas chromatograph were inlet temperature 80 o c, oven temperature 140 o c , air flow rate 300 ml/min., hydrogen flow rate 5ml/min., and flow rate in column 30 ml/min. the gasoline product was analyzed with simulated distillation gaschromatographic column using other gas chromatograph agilent technologies 6890n located in alduara refinery. the column type was hp 1 capillaries column ,length 100m, diameter 0.25mm, and film thickness 0.5µm was used to measure the gasoline composition produced from fluidized catalytic cracking unit. the operating condition of gas chromatograph were : initial temperature 35 o c, final temperature 300 o c , hydrogen flow rate 30 ml/min., air flow rate 400 ml/min., and nitrogen make up 30 ml/min. analysis of produced gases and gasoline were carried out according to astm 1945. olefin content in catalytic cracking gasoline was determined using irox 2000 located in alduara refinery. the concentration of the hydrogen sulfide in the cracked gases was determined using chemical analysis according to uop method 17259 in al-duara refinery. hydrogen gas produced from catalytic cracking was monitored using gas chromatograph 373 gasukurd kdgyo located in al-duara refinery according to uop 53973. fluid catalytic cracking of petroleum fraction (vacuum gas oil) to produce gasoline 36 ijcpe vol.11 no.4 (september 2010) fig. 1 schematic flow diagram of the fluidized catalytic cracking system: (1) burette vgo feeding; (2) burette water feeding; (3) valve; (4) dosing pump; (5) three way valve; (6) preheated section; (7)distributor (8)fluidized bed reactor section; (9)reactor separation section; (10) catalyst charge inlet; (11) double pipe heat exchanger; (12) control panel; (13) internal tube ice water bath; (14) separation and collection flask; (15) ice water bath ; (16) gas collection ; (17) water tank; (18) chilled water in; (19) chilled water out. 1 6 9 1 98 73 1 21 6 1 07 1 18 76 3 2 3 5 6 6 8 6 9 1 43 23 1 54 3 1 65 3 1 87 63 1 98 73 1 7 3 3 9 8 4 4 1 3 1 32 8 1 21 6 1 07 7 1 18 76 3 2 3 3 4 5 6 6 6 7 8 9 10 11 12 13 14 15 16 17 18 19 abdul halim a-k mohammed and karim khalifa esgair ijcpe vol.11 no.4 (september 2010) 37 results and discussion effect of superficial gas velocity on conversion and gasoline yield the effect of the ratio of superficial gas velocity to minimum fluidization velocity (uo/umf) on the vgo conversion and the gasoline yield was investigated in the range of 2 7. experiments were performed at different weights of prepared nay catalyst to vary the uo/umf ratio at constant weight hour space velocity .the experimental conditions of these tests are whsv of 10 hr -1 , reaction temperature of 480 o c, and atmospheric pressure. fig. 2 shows the effect of the ratio uo/umf on the conversion and gasoline yield.it is seen from this figure that the vgo conversion and the gasoline yield are affected by the inlet gas velocity, when the uo/umf ratio increases the vgo conversion and gasoline yield also increase up to uo/umf equals 5, after that the conversion and gasoline yield slightly decrease. therefore the value of uo/umf equal five will be selected for the study of the variation of whsv and temperature experiments. effect of whsv the effect of whsv on the vgo conversion and the yield of gasoline, gases, and coke was studied at different reaction temperatures, and uo/umf eqauls 5. figs. 3,4, and 5 show the effect of whsv on the vgo conversion at different reaction temperature for na form catalyst, nanh4 form catalyst, and nah form catalyst, respectively. as shown from these figures, the vgo conversion increases with decreasing of whsv at constant temperature. this means that the conversion of vgo is a function of reaction time for all catalysts, the increasing of the contact time of the feed molecules with the catalyst increases the vgo conversion in direct proportion to the amount of the catalyst and inversely proportional to the feed flow rate. the lower whsv increases the contact time and favors vgo conversion (figs. 3 to 5) and gasoline yield figs. 6 – 8. the lower whsv not only denotes to contact condition between oil vapor and catalyst, but also indicates the average activity of catalyst. with decreasing whsv, the contact opportunity between oil vapor and active sites increases, but the ratio of active sites contact with oil vapor to the overall active center decreases, and correspondingly, less active center on the surface per unit catalyst would be covered by coke. the gases produced from fluidized catalytic cracking unit at 500 o c , 10 whsv h -1 and na form catalyst was analyzed by gas chromatography and the components analysis of the gases is presented in table 3. this table shows that the percent of c3 and lighter gases were present 8.78 wt%, these include hydrogen, methane, ethane ,ethylene, propane 0 5 10 15 20 25 30 35 40 45 50 0 2 4 6 8 w t% uo/umf conversion gasoline yield fig. 2 effect of uo/umf ratio on the vgo conversion and gasoline yield fluid catalytic cracking of petroleum fraction (vacuum gas oil) to produce gasoline 38 ijcpe vol.11 no.4 (september 2010) ,and propylene .while the percent of isobutane ,n-butane, and butene was 8.1 wt%. to check the amount of thermal cracking of vacuum gas oil, experiments were performed without catalyst at temperature of 500 o c. the gasoline yield from thermal cracking was only 2.9 wt%. table 3 chemical analysis of gases gases volume % from gas product yield (wt%) from total product hydrogen 2.75 0.026 hydrogen sulfide 0.63 0.099 methane 14.38 1.388 ethane 16.42 1.823 ethylene 12.36 1.362 propane 14.31 2.754 propylene 11.21 2.135 iso butane 5.43 1.462 n. butene 13.65 3.589 n.butane 7.6 2.049 iso pentane 0.94 0.307 n. pentane 0.32 0.113 0 10 20 30 40 50 60 0 10 20 30 c o n ve rs io n (w t% ) whsv h-1 t=500 c t=480 c t=460 c t=440 c 0 10 20 30 40 50 60 70 0 10 20 30 c o n ve rs io n (w t% ) whsv h-1 t=500c t=480c t=460c t=440c 0 10 20 30 40 50 60 70 80 0 10 20 30 c o n ve rs io n (w t% ) whsv h-1 t=500c t=480c t=460c t=440c 1 21 6 fig. 3 effect of whsv on the vgo conversion at different temperatures for na –form zeolite catalyst fig. 4 effect of whsv on the vgo conversion at different temperatures for nanh4 -form zeolite catalyst fig. 5 effect of whsv on the vgo conversion at different temperatures for nah form zeolite catalyst abdul halim a-k mohammed and karim khalifa esgair ijcpe vol.11 no.4 (september 2010) 39 effect of temperature the effect of temperature on the vgo conversion and the yield of gasoline, gases, and delta coke was studied at whsv 10 to 25h -1 . figs. 9 – 11 show the effect of temperature on the vgo conversion for na form catalyst, nanh4 form catalyst, and nah form catalyst respectively. as shown in these figures, the vgo conversion increases with increasing the temperature. this may be attributed to the increase of temperature which accelerates intermolecular motions, assists the transformations of the reactants into new compounds and thus enhances the rate of chemical reaction. it is thermal activation which in the present case acts in conjunction with catalytic activation as mentioned by decroocq [11]. the higher temperature provided advantages in terms of a better feed vaporization which reduced coke formation by condensation reactions of poorly vaporized feed molecules. both the higher temperature and the resulting lower coke formation enhanced the diffusion of feed 0 5 10 15 20 25 30 0 10 20 30 g a so li n e y ie ld ( w t% ) whsv h-1 t=440c t=460c t=480c t=500c 0 5 10 15 20 25 30 35 0 10 20 30 g a so li n e y ie ld ( w t% ) whsv h-1 t=500c t=480c t=460c t=440c 0 5 10 15 20 25 30 35 40 0 10 20 30 g a so li n e y ie ld ( w t% ) whsv h-1 t=500c t=480c t=460c t=440c fig. 6 effect of whsv on the yield of gasoline at different temperatures for na –form zeolite catalyst fig. 7 effect of whsv on the yield of gasoline at different temperatures for nanh4-form zeolite catalyst fig. 8 effect of whsv on the yield of gasoline at different temperatures for nah-form zeolite catalyst fluid catalytic cracking of petroleum fraction (vacuum gas oil) to produce gasoline 40 ijcpe vol.11 no.4 (september 2010) molecules. also increased temperature enhances the overall conversion of gas–oils by enhancing the rates of protolysis of paraffins and decomposition reactions as α and β-scission. increasing the reaction temperature increases the gasoline yield as shown in figs. 12 14. figs. 9 – 14 show the nah form zeolite catalyst gives a highest vgo conversion and gasoline yield among na form, nanh4 form and nah form zeolite catalyst. the vgo conversion at 500 o c and whsv10 hr -1 by using faujasite type nay, nanh4y and nahy zeolite were 50.2%, 64.1% and 69.5wt% respectively, the gasoline yield were 24.8%, 30.5% and 36.8wt% respectively using the same operating condition. 15 20 25 30 35 40 45 50 55 420 440 460 480 500 520 c o n ve rs io n (w t% ) temperature oc whsv=25 whsv=20 whsv=15 whsv=10 15 20 25 30 35 40 45 50 55 60 65 420 440 460 480 500 520 c o n ve rs io n (w t% ) temperature oc whsv=25 whsv=20 whsv=15 whsv=10 15 25 35 45 55 65 75 420 440 460 480 500 520 c o n ve rs io n (w t% ) temperature oc whsv=25 whsv=20 whsv=15 whsv=10 fig. 9 effect of temperature on the vgo conversion at different whsv for na-form zeolite catalyst fig. 10 effect of temperature on the vgo conversion at different whsv for nanh4form zeolite catalyst fig. 11 effect of temperature on the vgo conversion at different whsv for nahform zeolite catalyst abdul halim a-k mohammed and karim khalifa esgair ijcpe vol.11 no.4 (september 2010) 41 fig. 14 effect of temperature on the yield of gasoline at different whsv for nahform zeolite catalyst relation between vgo conversion and gasoline yield figs. 15, 16 and 17 show the relation between vgo conversion and gasoline yield using na form, nanh4 form, and nah form zeolite catalysts respectively. as shown in these figures, the gasoline yield increases with increasing the vgo conversion. in general, it may be noted that when a vacuum gas oil is processed in a fluidized bed over zeolite catalyst the yield of gasoline first increases , then passes through a maximum, and finally decreases, whereas the weight yield of gases keeps increasing with the degree of conversion of the feed. this situation is commonly observed in catalytic cracking because a set of consecutive reaction .the primary cracking of the vacuum gas oil constituting the feed, produces an unsaturated gasoline, which is usually the wanted product. 0 5 10 15 20 25 30 420 440 460 480 500 520 g a so li n e y ie ld (w t% ) temerature oc whsv=25 whsv=20 whsv=15 whsv=10 0 5 10 15 20 25 30 35 400 450 500 550 g a so li n e y ie ld ( w t% ) temperature oc whsv=25 whsv=20 whsv=15 whsv=10 0 5 10 15 20 25 30 35 40 420 440 460 480 500 520 g a so li n e y ie ld ( w t% ) temerature oc whsv=25 whsv=20 whsv=15 whsv=10 fig. 12 effect of temperature on the yield of gasoline at different whsv for na-form zeolite catalyst fig. 13 effect of temperature on the yield of gasoline at different whsv for nanh4form zeolite catalyst fluid catalytic cracking of petroleum fraction (vacuum gas oil) to produce gasoline 42 ijcpe vol.11 no.4 (september 2010) however this gasoline may also react, either by undergoing a secondary cracking (usually referred to as over cracking) to gases compounds or oligomerization and cycloaddition of its unsaturated components to dehydrogenated products and coke [11]. thus, if the degree of the conversion of the feed is high ,the gasoline formed as an intermediate product is partially transformed to light secondary products and to coke deposits, both of which reduce the gasoline yield of the unit .to prevent the occurrence of this degradation process, which seriously impairs the profitability of the operation , the degree of the conversion is usually set at a value corresponding to the maximum yield of gasoline .to obtain an overall maximum gasoline yield, the design of reaction section to be modified, the incompletely converted or unconverted fraction of the feed is separated from light products for subsequent incorporation in various heavy fuel, are replaced by recycle reactors in which the unconverted feed is processed again [12]. from figs. 15 ,16, and 17 it can be seen that gasoline yield and vgo conversion are always increased by whsv decrease. it means that the reaction is below the secondary cracking (over cracking). 0 5 10 15 20 25 30 0 20 40 60 g a so li n e y e il d (w t% ) conversion (wt%) 0 5 10 15 20 25 30 35 0 20 40 60 80 g a so li n e y e il d ( w t% ) conversion(wt%) whsv=10 – 25 h -1 whsv=10-25 h -1 fig. 15 relation between conversion (wt%) and gasoline (wt%) at 500 o c for na –form zeolite catalyst. fig. 16 relation between conversion (wt%) and gasoline (wt%) at 500 o c for nanh4 -form zeolite catalyst abdul halim a-k mohammed and karim khalifa esgair ijcpe vol.11 no.4 (september 2010) 43 the chemical composition of the gasoline the chemical composition of the catalytic cracking gasoline fractions was analyzed using simulated distillation gas chromatography depending on the end point temperatures of distillation step. these fractions are ibp 110 o c, ibp 180 o c, ibp 200 o c, and ibp 220 o c. table 4 shows a comparison between the chemical composition of cracked gasoline fraction produced in this work with those obtained from california gas oil and gachsaran gas oil studied by eastwood et al [13]. this table shows that the paraffins and olefins decreases with increasing the end point temperature , naphthenes approximately kept constant with the end point change, while aromatics increases with increasing the end point temperature. this table also shows the high concentration of olefins in all fractions, and this may be due to the decreasing hydrogen transfer reactions within catalytic cracking reactions. baker [14] and whittington et al [15] measured the chemical composition and research octane number of cracked gasoline produced from different feedstock and found that the ron depended mainly on the aromatic content as shown in figure 18. fig. 18 was used for the estimation of the ron of gasoline produced at 500 o c and 10 h -1 whsv. the estimation value of ron was 97 which means that the produced gasoline could be used as high octane basic automobile gasoline. table 4 a comparison between the chemical compositions of gasoline fractions chemical composition of cracked gasoline(vol. %) paraffins naphthenes olefins aromatics c5-110 o c 36.40 3.00 43.1 17.5 c5-180 o c 22.69 3.01 41.60 32.7 c5-200 o c 15.70 3.00 40.2 41.1 c5-220 o c 12.08 3.03 34.1 50.79 c5-220 o c from california gas oil [17] 8.70 10.40 43.70 37.30 c5-220 o c from gachsaran gas oil [17] 21.20 15.70 30.20 33.10 0 5 10 15 20 25 30 35 40 0 20 40 60 80 g a so li n e y e il d ( w t% )% conversion(wt%) whsv=10-25 h -1 fig. 17 relation between conversion (wt%) and gasoline (wt%) at 500 o c for nah form zeolite catalyst fluid catalytic cracking of petroleum fraction (vacuum gas oil) to produce gasoline 44 ijcpe vol.11 no.4 (september 2010) c0nclusions the experimental results indicate that higher temperature 500 o c was favorable for conversion of vacuum gas oil to gasoline and other product. 1the experimental results indicate that the gasoline yield increased from 17.2 to 36.8 wt% when the whsv decreases from 25 to 10 h -1 for nah form zeolite at500 o c. 2the results indicate that the effect of whsv is higher than the effect of temperature on the vgo conversion and gasoline yield within the process variables. 3the best operation condition was 500 o c and whsv10 h -1 which gave a vgo conversion 69.5wt% and gasoline yield 36.8wt% for nah form zeolite. 4the estimated research octane number of produced gasoline at 220 o c was 97. 5the composition of cracked gasoline is a function of its end point temperature .the aromatic content of gasoline produced increases from 17.5 to 50.79wt% while paraffins decrease from 36.40 to 12.08wt%,olefins decrease from 43.10 to 34.10 wt% with end point temperature increases from 110 to 220 o c. the naphthene remain approximately constant with end point increasing. 6the activity of faujasite type y zeolite nah form is a highest among na form, nanh4 form and nah form. references [1]barajasa,j.r.h., roma´na,r.v., and sotelob,d.s., (2006),“ multiplicity of steady states in fcc units: effect of operating conditions ”, fuel, 85, 849–859. [2]reza sadeghbeigi, (2000), “fluid catalytic cracking handbook design, operation and troubleshooting of fcc facilities”, elsevier inc. [3]magee, j. s., and mitchell, m. m., (1993), “fluid catalytic cracking science and technology”, elsevier, amsterdam,. [4]wilson, j.w., (1997), “fluid catalytic cracking technology and operation”, pennwell, tulsa,. [5]habib, e.t., zhao, x., yaluris, g., cheng, w.c., boock, l.t., gilson, j.-p., in: guisnet, m., gilson, j.-p.(eds.), (2002), “zeolites for cleaner technologies”, imperial college press, london, , p. 105. [6]corma, a., forne´s, v., martinez, a. , melo, f.v. , pallota, o. , in: grobet, p., mortier, w.j., vansant, e.f., schulzekloff, g. (eds.), (1988), “innovation in zeolite materials science”, studies in surface science and catalysis, vol. 37, elsevier, amsterdam, , p. 495. [7]sie, s.t., in: jansen, j.c., sto¨cker, m., karge, h.g., weitkamp, j. (eds.), (1994), “advanced zeolite science and applications”, studies in surface science 0 5 10 15 20 25 30 35 40 45 50 90 92 94 96 98 a ro m a ti c( w t% ) ron fig. 18 relation between ron and aromatic content for cracked gasoline abdul halim a-k mohammed and karim khalifa esgair ijcpe vol.11 no.4 (september 2010) 45 and catalysis, vol. 85, elsevier, amsterdam, , p. 587. [8]dwyer, f.g., degnan, t.f., in: magee, j.s., mitchell m.m., (eds.), (1993), “shape selectivity in catalytic cracking in fcc: science and technology”, studies in surface science and catalysis, vol. 76, elsevier, amsterdam, p. 499. [9]fu, a., hunt, d., bonilla, j. a., and batachari, a., (1998), “deep catalytic cracking plant produces propylene in thailand”, oil and gas journal, january 12, 49–53. [10]michael stocker, (2005),“ gas phase catalysis by zeolites”, microporous and mesoporous materials, 82, 257–292 [11]danial decroocq , ,(1984) ,“catalytic cracking of heavy petroleum fractions”, imprimerir louis-jean, paris. [12]weitkamp, j. , traa, y. , in: ertl, g. , kno' zinger, h., weitkamp, j. (eds.), (1997) “handbook of heterogeneous catalysis”, wiley-vch, weinheim, , p. 2039. [13]eastwood b.,s.c., plank,c.j., and weisz.p.. ,(1971). “proceedings of the eight word petroleum congress“, vol. 4 p.245 .applied science publishers, london. [14]baker,r.w., (1972) “ presentation at the davison – crosfield catalyst symposium” great british, april 10-11. [15]whittington, f.l., murphy,j.r., and lutz,i.k., ,(1972) ,oil and gas journal , oct.3059. النتاج الكازولين (زيت الغاز الفراغي)التكسير الحفازي المائع لمقطع نفطي :الخالصة حن اسخخذام الخكسٍز الحفاسي الوائغ لشٌج الغاس الذي حصل ػلٍه هي الخقطٍز الفزاغً لوخبقً الخقطٍز الجىي فً وحذة . سٌىالٌج الوحضز yالشٌىث فً هصفى الذورة باسخخذم الؼاهل الوساػذ فاٌىجاسٍج ًىع و صٍغت الهٍذروجٍي nanh4yو صٍغت االهىًٍىم , nay درسج الفؼالٍت الحفاسٌت للفٍىجٍساٌج بصٍغت الصىدٌىم nahy 500 – 440 سٌىالٌج باسخخذام وحذة حجزٌبٍت بحذود درجاث الحزارة بٍي o c سا25 – 10 وسزػت فزاغٍت بٍي -1 . و صٍغت الهٍذروجٍي nanh4yو صٍغت االهىًٍىم , nayحن حؼٍٍي الفؼالٍت الحفاسٌت للفٍىجٍساٌج بصٍغت الصىدٌىم nahy لقذ كاًج ًسبت ححىٌل الوخفاػالث الى . سٌىالٌج بصٍغت ححىٌل الوخفاػالث الى هخخلف الٌىاحج وًسبت الكاسولٍي الٌاحج 500ًىاحج ػٌذ درجت حزارة o c سا10 وسزػت فزاغٍت -1 واى اًخاجٍت الكاسولٍي . ػلى الخىالً%69.5 و %64.1 و 50.2% . ػلى الخىالً %36.8 و %30.5 و %24.8لٌفس الظزوف الخشغٍلٍت كاًج االولٍفٌٍاث , للكاسولٍي الوٌخج باى ًسبت البزافٌٍاث gas chromatographyبٌٍج ححلٍل الغاسالكزوهاحىغزافً . واالروهاحٍاث حخغٍز حبؼا لخغٍز درجت حزارة ًهاٌت الخقطٍز لوقطغ الكاسولٍي iraqi journal of chemical and petroleum engineering vol.12 no.3 (september 2011) 25-33 issn: 1997-4884 aluminum leachability evaluation from oven dried alum sludge sami mohammed zaboon university of baghdad , college of engineering ,chemical engineering department,baghdad, iraq. abstract phosphorus and dye (direct black) removal for small – scale wastewater applications were investigated using oven dried alum sludge (ods).the use of alum sludge not only provides a low cost technique but also reduces the hazard and the cost related to the disposal of large amount of alum sludge. phosphorus and dye removal exceeds 90% for all operating conditions applied in the research. the residuals generated during the treatment of wastewater were further tested to study the possibility of aluminum leaching from oven dried alum sludge during the adsorption of phosphorus and dye. these tests observed a reduction in aluminum leaching indicating a lower risk imposed on land and surface water based on disposal options rather than on alum sludge disposal. the leaching of aluminum was observed to be mostly below 1 mg/l for a ph solution of 6 and 7 for both processes of phosphorus and dye removal. however, the ph of 5 seemed to have a concentration of more than 1mg/l of aluminum. introduction biosolid management is considered very important, as there are considerable amounts of biosolids generated due to anthropogenic reasons. alum sludge, a biosolid generated in the coagulation process in a water treatment plant, is one ofthem. the reuse of alum sludge in other applications has been considered by many researchers in recent years.divalent and trivalent cation based materials are known to be effective for phosphorous and dyes removal (maruf, m., 2006,sarmad, a., 2009 and rasha, h., 2010). alum sludge is typically known to be a mixture of various forms of aluminium hydroxide (wang et al., 1992). the use of waste material (alum sludge) not only can provide low cost appropriate technological alternative for small – scale applications, but also can reduce the hazard and the cost of the disposal of large amount of alum sludge.physical and chemical methods are considered very expensive in terms of energy and reagent consumption. another account that limits their use is the excessive sludge they generate (yokubuet al., 2008).adsorption has been found to be superior to other techniques for water reuse in terms of initial cost, simplicity of design, ease of operation and insensitivity to toxic substances.at the present time, there is a growing interest in using low – cost, commercially available materials for the adsorption of phosphorous and dyes.sarmad(2009) investigated the removal of phosphorous from wastewater by using oven dried alum sludge. the results showed that the oven dried alum sludge were effective for adsorbing phosphorous and the removal percentage was up to 85%. university of baghdad college of engineering iraqi journal of chemical and petroleum engineering aluminum leachability evaluation from oven dried alum sludge 26 ijcpe vol.12 no.3 (september 2011) -available online at: www.iasj.net rash h. (2010) investigated the removal of dyes from wastewater by using oven dried alum sludge. the results showed that the removal was 92%. phosphorous and dyes adsorption onto oven dried alum sludge shown in the researches mentioned earlier provided an environment friendly management option for water treatment residuals . however, the residuals generated during the process of adsorption on oven dried alum sludge are also needed to be managed due to large amount of aluminum in these residuals and aluminum in water has proven to produce chronic toxicity (allin and wilson ,1999). the chemical speciation of aluminum in natural water regulates its mobility, bioaviability and toxicity. aluminum normally undergoes hydration reaction in aqueous system to an extent governed by the ligand properties and concentrations of aluminum, and hydrogen ion (faust and aly, 1999). hydrolysis increases as the solution ph increases resulting in a series of aluminum hydroxide complexes. alum sludge is mostly composed of these series of aluminum hydroxide complexes (i.e. al(oh)2 + , al(oh)3, al(oh)4, al +3 , … etc). the objective of this study was to study the leachability of residuals (i.e. aluminum) generated from adsorption of phosphorous and dyes from small – scale wastewater on alum sludge.  materials 1. adsorbent  alum sludge alum sludge is a waste material generated during the coagulation / sedimentation process in a drinking water treatment plant. alum sludge that is generated from drinking water treatment contains precipitated alum hydroxide and the contaminants that are specific to row chemistry. in this research, alum sludge was collected from alqadisiya treatment plant, baghdad governorate, iraq. inorganic materials in alum sludge are presented in table 1. table 1, inorganic materials in alum sludge the alum sludge used in this research was heated in an oven at 105 c o for 24 hours. the dried sludge was then cooled to room temperature. the sludge particles were then crushed to produce a particle size of 2.36 mm. the physical properties are listed in table 2. table 2, physical properties of oven dried alum sludge 2. wastewater  orthophosphate(potassium dihydrogen orthophosphate kh2po4) was used in this study to prepare a phosphorus solution. physical properties of kh2po4 are listed in table3. constituent weight percent aluminum 3.38 % iron 0.819 % manganese 0.16 % chromium 0.013 % vanadium 0.002 % zinc 0.0098 % lead 0.0001 % barium 0.0001 % arsenic 0.0002 % item name oven dried alum sludge bulk density (kg/m 3 ) 786.7 particle porosity 0.7 bed porosity 0.65 sami mohammed zaboon -available online at: www.iasj.net ijcpe vol.12 no.3 (september 2011) 27 table 3, main properties of adsorbate name of component potassium dihydrogen orthophosphate chemical symbol kh2po4 name of company the british drug houses ltd / england molecular weight 136.09 kg / kg.mole assay (acidimetric) 99 to 101per cent chloride (cl) not more than 0.01 per cent sodium (na) not more than 0.2 per cent sulphate (so4) not more than 0.05 per cent ph (1 percent solution) 4.5 to 4.7  deionized water was spiked with kh2po4 to prepare a phosphorus solution of (10) mg/l, this concentration was achieved by 0.0143 mg kh2po4 with liter of water. the phosphorus concentration was chosen as typical phosphorus concentration in many wastewaters. the same thing was used to prepare the dyes solutions.  black direct dye of 10 mg/l was used as adsorbate. the concentration of dye was measured with shimatzu uv spectrophotometer at wave length corresponding to the maximum absorbance of 566nm.  experimental arrangements the schematic representation of experimental equipment is shown in figure 1.  adsorption column the fixed bed adsorber studies were carried out in q.v.f. glass column of 2 in. (50.8 mm) i.d. and 50 cm height.the oven dried alum sludge was confined in the column by fine stainless steel screen at the bottom and a glass cylindrical packing at the top of the bed to ensure a uniform distribution of influent through the alum sludge.the influent solution was introduced to the column through aperforated plate, fixed at the top of the column. experiments were carried out at various ph solutions (5 – 7) with keeping other variables constant (i.e. initial phosphorus and dyeconcentration, particle size, flow rate and bed depth). the experimental procedure for column system experiments is as follow:  the oven dried alum sludge with particle size of 2.36 mm was placed in the adsorption column for the desired bed length (i.e. 40 cm)  the wastewater with the desired concentration was prepared in the feed container, using distilled water (i.e. phosphorusconc. 5 ppm and dye conc. 10 ppm).  the wastewater was pumped to the adsorption column through the calibrated rotameter at the desired flow rate (i.e. 1.67 × 10 -6 m 3 /s).  samples were taken periodically, the concentration of phosphorus, dye, and aluminum in these samples were measured using uv spectrophotometer and atomic absorption. aluminum leachability evaluation from oven dried alum sludge 28 ijcpe vol.12 no.3 (september 2011) -available online at: www.iasj.net fig. 1, schematic representation of experimental equipment  tests for characterizing oven dried alum sludge a. ir spectroscopy the samples for infrared spectra (bruker vector ft-ir spectrometers) were prepared with methylene chloride (ch2cl2) mulls oncsi plates. vibrational spectra were reported in wavelengths (cm -1 ) against ranked infrared absorption, where the value of the wavelengths at peak corresponds to the characteristics of the active groups present on the surface of the material. this test was done in the college of science / chemistry dept. and the result is shown in figure 2. b. x-ray diffraction x-ray powder diffraction patterns of ods were obtained from gently pressed specimens of random powder particles that are less than 0.45 μm. powder x-ray diffraction data were collected from 10 to 60° 2 with a nicolet x-ray powder diffractometer (graphite monoachromatized cu kr radiation, 0.05° 2 step size, and 2-s count time per steps).this test was carried out in theministry of science and technology and the result obtained is shown in figure 3. c. specific surface area in practice, the method mostly used for determining specific surface area is to drain sampling point centrifugal pump feed tank effluent tank feed distributor rotameter sampling point to drain feed adsorber sami mohammed zaboon -available online at: www.iasj.net ijcpe vol.12 no.3 (september 2011) 29 the bet method (brunauer, emmett and teller) based on the physical adsorption of an inert gas at constant temperature of liquid nitrogen. the principle of measurement consists of determining the point when molecular layer of gas covers the surface (lepage, 1987).the apparatus of type carlo-erabasorptomic series 1800 was connected to computer in which allenecessary bet principles were run from the information of the pressure decrease. this test was done in petroleum research and development center. the experimental results showed that oven dried alum sludge had an average specific surface area of 191 m 2 /g. fig. 2, ir spectroscopy of ods results and discussion to study the possibility of aluminum contaminants leaching from oven dried alum sludge,a series of experimental breakthrough curves were carried out for adsorption of phosphorus and dyes using oven dried alum sludge. the experiments includedstudying the effect of ph solution (5, 6, and 7) on phosphorus and dyes adsorption onto oven dried alum sludge and aluminum leaching from the adsorbent. fig. 3, x-ray diffraction of ods  phosphorus adsorption: the removal of phosphorus by using oven dried alum sludge, as a function of different values of ph is presented in figures4, 6, and 8. varied values of ph solution are 5, 6 and 7. the other variables (phosphorus concentration 5 ppm, operating temp. 25c, bed height 40 cm, particle size 2.36 mm) are kept constants. the results indicate that ph had little effect on the adsorption density. however, ph solution of 6 appeared to produce maximum phosphorus adsorption density. in the same time, tests conducted on oven dried alum sludge showed lower tendency to leach aluminum. aluminum leaching was in general high in the beginning of the experiments as shown in figures 5, 7, and 9. however, over time, aluminum leaching decreased. in many cases, aluminum concentrations were lower than the concentration present in the raw water because of the structural variation in alum sludge surfaces during the drying process. also, the ph of the system affects both metal ion and waste water solution. the solution aluminum leachability evaluation from oven dried alum sludge 30 ijcpe vol.12 no.3 (september 2011) -available online at: www.iasj.net suffers protonation as the ph of the system decreases: if the solution is unable to ionize as a result of the concentration of hydrogen ion, it will not be able to form a complex with a metal ion, and hence extraction will not occur. the effluent ph was understandably dependent on the influent ph. an influent ph 5 produced effluent ph of (4.7-5.5). similarly an influent ph 6 generated an effluent ph range (5.66.3) and an influent ph 7 generated an effluent ph range of (6.5-7.5). this was due to the adsorption and desorption of h + ions during the adsorption of phosphorus on alum sludge. an effluent ph below 4.5 is not suitable for disposal in surface water. the effluent ph can be increased prior to disposal in surface water. however, the cost of chemicals to reduce initial ph and to increase final ph and hazards of dealing with increased amount of sludge would pose negative interest for ph control. in general, a ph value in the range of 6 – 9 is reasonable for wastewaters before disposal into surface water. fig. 4, phosphorus ratio (c/co) concentration with time operating conditions:phosphorous conc. = 5ppm, operating temperature=25⁰c, bed height = 40cm, column diameter= 2in., particle size = 2.36 mm, ph=5, q=1.67×10 -6 m 3 /s. fig. 5, aluminum concentration with time operating conditions: phosphorous conc. = 5ppm, operating temperature= 25⁰c, bed height = 40cm, column diameter= 2in., particle size = 2.36 mm, ph=5, q=1.67×10 -6 m 3 /s. fig. 6, phosphorus ratio (c/co) concentration with time operating conditions: phosphorous conc. = 5ppm, operating temperature= 25⁰c, bed height = 40cm, column diameter= 2in.,particle size = 2.36 mm, ph=6, q=1.67×10 -6 m 3 /s. 0 0.2 0.4 0.6 0.8 1 0 5000 10000 15000 20000 25000 30000 p h o s p h o r o u s c o n c . c / c o time, sec 0.0 0.4 0.8 1.2 1.6 2.0 0 5000 10000 15000 20000 25000 30000 a lu m in u m c o n c . m g / l time, sec 0 0.2 0.4 0.6 0.8 1 0 5000 10000 15000 20000 25000 30000 p h o s p h o r o u s c o n c . c / c o time, sec h + -h + h + -h + ha + a ¯ h2a sami mohammed zaboon -available online at: www.iasj.net ijcpe vol.12 no.3 (september 2011) 31 fig.7, aluminum concentration with time operating conditions: phosphorous conc. = 5ppm, operating temperature= 25⁰c, bed height = 40cm, column diameter= 2in., particle size = 2.36 mm, ph=6, q=1.67×10 -6 m 3 /s.  direct black dye adsorption the removal of direct black dye by using oven dried alum sludge, as a function of different values of ph is presented in figures 10, 12, and 14. varied values of ph are 5, 6, and 7. the other variables (dye concentration 10 ppm, operating temperature 25 o c, bedheight 40 cm, particle size 2.36 mm)are kept constants. the effluent ph levels were in the range of 5.5 – 7.5 for an is influent ph of 5 – 7 and this mostly suitable for disposal in surface water.the results showed that the oven dried alum sludge was effective in adsorbing dyes with removed efficiency up to 93%. aluminum leaching was in general about 1 mg/l in the beginning of the experiments for each ph a shown in the figures 11, 13, and 15. however, over time, aluminum leaching decreased to less than 0.2 mg/l; this was due to the structural variation in alum sludge surfaces during drying process and the effect of ph solution that discussed previously. fig. 8, phosphorus ratio (c/co) concentration with time operating conditions: phosphorous conc. = 5ppm, operating temperature= 25⁰c, bed height = 40cm, column diameter= 2in., particle size = 2.36 mm, ph=7, q=1.67×10 -6 m 3 /s. fig.9, aluminum concentration with time operating conditions: phosphorous conc. = 5ppm, operating temperature= 25⁰c, bed height = 40cm, column diameter= 2in., particle size = 2.36 mm, ph=7, q=1.67×10 -6 m 3 /s. fig.10, direct black dye concentration with time operating conditions: phosphorous conc. = 5ppm, operating temperature= 25⁰c, bed 0.0 0.4 0.8 1.2 1.6 2.0 0 5000 10000 15000 20000 25000 30000 a lu m in u m c o n c ., m g / l 0 0.2 0.4 0.6 0.8 1 0 5000 10000 15000 20000 25000 30000 p h o s p h o r o u s c o n c . c / c o time, sec 0.0 0.4 0.8 1.2 1.6 2.0 0 5000 10000 15000 20000 25000 30000 a lu m in u m c o n c ., m g / l time, sec 0 0.2 0.4 0.6 0.8 1 0 5000 10000 15000 20000 25000 30000 d y e c o n c . c / c o time, sec aluminum leachability evaluation from oven dried alum sludge 32 ijcpe vol.12 no.3 (september 2011) -available online at: www.iasj.net height = 40cm, column diameter= 2in., particle size = 2.36 mm, ph=5, q=1.67×10 -6 m 3 /s. fig.11, aluminum concentration with time operating conditions: phosphorous conc. = 5ppm, operating temperature= 25⁰c, bed height = 40cm, column diameter= 2in., particle size = 2.36 mm, ph=5, q=1.67×10 -6 m 3 /s. fig.12, direct black dye concentration with time operating conditions: phosphorous conc. = 5ppm, operating temperature= 25⁰c, bed height = 40cm, column diameter= 2in., particle size = 2.36 mm, ph=6, q=1.67×10 -6 m 3 /s. fig.13, aluminum concentration with time operating conditions: phosphorous conc. = 5ppm, operating temperature= 25⁰c, bed height = 40cm, column diameter= 2in., particle size = 2.36 mm, ph=6, q=1.67×10 -6 m 3 /s. fig.14, direct black dye concentration with time operating conditions: phosphorous conc. = 5ppm, operating temperature= 25⁰c, bed height = 40cm, column diameter= 2in., particle size = 2.36 mm, ph=7, q=1.67×10 -6 m 3 /s. fig.15, aluminum concentration with time 0.0 0.4 0.8 1.2 1.6 2.0 0 5000 10000 15000 20000 25000 30000 a lu m in u m c o n c . m g / l time, sec 0 0.2 0.4 0.6 0.8 1 0 5000 10000 15000 20000 25000 30000 d y e c o n c . c / c o time, sec 0.0 0.4 0.8 1.2 1.6 2.0 0 5000 10000 15000 20000 25000 30000 a lu m in u m c o n c ., m g / l time, sec 0 0.2 0.4 0.6 0.8 1 0 5000 10000 15000 20000 25000 30000 d y e c o n c . c / c o time, sec 0.0 0.4 0.8 1.2 1.6 2.0 0 5000 10000 15000 20000 25000 30000 a lu m in u m c o n c ., m g / l sami mohammed zaboon -available online at: www.iasj.net ijcpe vol.12 no.3 (september 2011) 33 operating conditions: phosphorous conc. = 5ppm, operating temperature= 25⁰c, bed height = 40cm, column diameter= 2in., particle size = 2.36 mm, ph=7, q=1.67×10 -6 m 3 /s. conclusion  oven dried alum sludge was effective in adsorbing phosphorus and direct black dye.  experimental findings indicated the residuals generated during adsorption of phosphorus and dye on oven dried alum sludge would not cause alarming level of aluminum leaching. therefore, there were low chances of these residuals being a problem for disposal. references  marufmortula, meaghan gibbons, and a. gagnon, 2006, "phosphorus adsorption by naturally-occurring materials and industrial by-products", j. environ. eng. sci., 6, pp 157-164.  yakubu, m.k., gumel m.s., and abdullahi a.m., 2008, "use of activated carbon from date seeds to treat textile and tannery effluents", african journal of science and technology (ajst), science and eng. series, 9(1), p. 39 – 49.  sarmad, a.r., 2009, "phosphorus removal from wastewater using alum", m. sc. thesis, university of baghdad.  wang, m.c., hull, j.q., jao, m., dempsey, b.a., and cornwell, d.a., 1992,"engineering behavior of water treatment sludge", journal of environmental engineering, 118 (6), 848 – 864.  rasha h. salman, 2010,"removal of dyes from textile effluent by adsorption onto oven dried alum sludge", journal of engineering, no.2, 16 (5249 – 5262).  allin, c.j., and wilson, r.w., 1999,"behavioral and metabolic effects of chronic exposure to sublethal aluminum in acidic soft water in juvenile rainbow trout", canadian journal of fisheries and aquatic science, 56 (670 – 678).  faust, s.d., and aly, o.m., 1999, "chemistry of water treatment", 2 nd edition, lewis publishers. ijcpe vol.10 no.2 (june 2009) iraqi journal of chemical and petroleum engineering vol.10 no.2 (june 2009) 35-42 issn: 1997-4884 the effect of extraction temperature and solvent to oil ratio on viscosity index of mixed-medium lubricating oil fraction by using solvents extraction abdul-halim a. mohammed * and mohammed j. yass kheder * chemical engineering department college of engineering university of baghdad – iraq abstract in this study two types of extraction solvents were used to extract the undesirable polyaromatics, the first solvent was furfural which was used today in the iraqi refineries and the second was nmp (n-methyl-2-pyrrolidone). the studied effecting variables of extraction are extraction temperature ranged from 70 to 110°c and solvent to oil ratio in the range from 1:1 to 4:1. the results of this investigation show that the viscosity index of mixed-medium lubricating oil fraction increases with increasing extraction temperature and reaches 107.82 for nmp extraction at extraction temperature 110°c and solvent to oil ratio 4:1, while the viscosity index reaches to 101 for furfural extraction at the same extraction temperature and same solvent to oil ratio. the increase in solvent to oil ratio has a higher effect on increasing the viscosity index of lubricating oil fraction compared with extraction temperature in furfural and nmp extraction. further more, the results show that the percentage yield of raffinate was decreased as the extraction temperature and solvent to oil ratio increases for furfural and nmp extraction. introduction the nmp and furfural extraction processes uses as the solvents to remove the condensed ring aromatics and polar components from the lubricating oil distillates and bright stocks. this process was developed as a replacement for phenol extraction because of the safety, health, and environmental problems associated with the use of phenol. several differences between the characteristics of nmp,furfural and phenol make furfural and nmp need to modify the phenol plant design. these differences include a 22 °c higher boiling point for nmp, a 64 °c lower in freezing point, complete miscibility of nmp with water, no azeotrope formation of nmp with water while the differences with furfural include 21°c lower boiling point for furfural, a 76.5°c lower in freezing point and high miscibility of furfural with water [1]. the non – toxic nature, high solvent power, good selectivity and excellent thermal and chemical stabilities of nmp, as well as its applicability to extraction of both paraffinic and naphthenic feed stocks, make it an attractive solvent for the extraction of lubricating oil stocks [2]. while lubricating oils (lube oils) include a large number of liquid petroleum products which have been developed for lubricating various types of machinery [3]. the lube oil base stocks are prepared from selected crude oils by distillation and special processing to meet the desired qualifications. generally, lubes have a boiling point above 350°c and these are obtained as the main products from vacuum distillation units. liquid lubricants find the greatest favor in engineering applications because they readily provide separation of surface when correctly applied, and have a high cooling ability when circulated through the bearing area. also, they characterize by availability in suitable viscosities, low volatility, inertness (resistance to deterioration of the lubricant), corrosion protection (resistance to deterioration of the sliding surfaces) and low cost [4]. the liquids available for use as lubricating media can be classified into three types: animal or vegetable oils; university of baghdad college of engineering iraqi journal of chemical and petroleum engineering anodic polarization of anodized aluminum alloy 5052 2 ijcpe vol.10 no.2 (june 2009) mineral oils; and synthetic oils. mineral oils are the most popular lubricants because of their relatively low cost which results from two factors. firstly, they are produced from the residue obtained from the distillation of crude oil which is otherwise used as fuel oil and is consequently cheap. secondly, the advanced processing and blending techniques make possible a large of different types of oils in the same processing equipment [5]. the aim of the present work is to obtain lubricating oil with high viscosity index by extracting poor quality components like (polycyclic aromatic and naphthenearomatic hydrocarbons with short side chains, and unsaturated) which naturally presented in raw lubricating oil fraction by using furfural and nmp solvents. the study include studying the effect of operating variables (extraction temperature and solvent to oil ratio) viscosity index and raffinate yield making a comparison between the performance of furfural and nmp solvents. experimental work mixed-medium lubricating oil properties. in this work a mixed lube oil medium distillate fraction obtained from vacuum distillation unit of lube oil plant in daura refinery was used. the feedstock for vacuum distillation unit was atmospheric residue produced from mixed iraqi crude oils (60 % of basrah, 30 % of kirkuk, 10 % of sharki-baghdad). table 1 shows the properties of the mixed-medium-lube oil fraction used in this investigation. table 1 properties of the mixed-medium lubricating oil. no. specification values 1 specific gravity@ 60/60 °f 0.89 2 viscosity, cst, @ 40°c 78.75 3 viscosity, cst, @ 100°c 21.25 4 viscosity index 49 5 coc flash point, °c 141 6 pour point, °c 21 7 sulfur content, % wt 2.975 8 color, astm-d1500, at 25°c 5.26 9 refractive index 1.4915 solvents the solvents used in this work are furfural and n-methyl2-pyrrolidone. table 2 shows the properties of these solvents. table 2 properties of furfural and nmp solvents. no. specification values for nmp values for furfural 1 boiling point, °c 202 161 2 freezing point, °c -24 -36.5 3 viscosity, cps, @25°c 1.65 1.49 4 density (d4 25 ), g/cm3 1.0270 1.1563 5 coc flash point, °c 95 68 6 refractive index 1.4690 1.5235 extraction experiments in the present work a laboratory batch extraction unit was used. fig. 1 shows the schematic diagram of the laboratory extraction unit. this unit consists of a bench scale 1-liter, 3-necks pyrex flask extraction apparatus. the middle flask neck was connected with the mixer; the second neck was connected with reflux condenser and the third neck was connected with thermometer. electrical mixer with 45 mm diameter paddle was used to mix the oil with the extraction solvent inside the extractor. the extractor was heated and controlled by using an oil bath (with heater and thermostat) in which the extractor is immersed. the lube oil fraction was mixed with the extraction solvent in the extractor at controlled specified temperature. mixing the two materials at the specified temperature was continued for a period of 30 min then the mixture was left at the specified temperature for 30 min to be separated in to two phases. the upper liquid phase is light raffinate solution and the bottom liquid phase is heavier extract solution. after steady state indicated by constant interface level, the two phases were separated by using a separating funnel. the two solutions were weighted to ensure material balance closure [2, 6]. the extraction process studied in the temperature range of 70-110°c and solvent to oil ratio of 1:1 to 4:1. dr. aparel s. yaro and ala’a mishgel ali al-asade 3 ijcpe vol.10 no.2 (june 2009) fig. 1 schematic diagram of the laboratory-extraction. test methods 1. density and specific gravity the density and specific gravity of lubricating oil were measured according to astm-d1481. 2. viscosity the viscosity of lubricating oil was measured according to astm-d445. 3. viscosity index the viscosity indexes of lube oil distillate fraction and raffinate oil were calculated according to astm-d2270. 4. refractive index the refractive index of lubricating oil was measured according to astm-d1218. the refractive index is measured by the critical angle method with a bausch and lomb precision refractmeter using monochromatic light. this method is used for hydrocarbons having an astm color less than 4 (darkness)and it is limited to measuring refractive indices between 1.33 and 1.50, for temperature between 20 and 30°c [7]. results and discussion effect of operating variables and solvent type on raffinate viscosity. the viscosity of lubricating oil fraction is very important factor in the manufacture of lubricating oils, and the correct operation of the equipment depends upon the appropriate viscosity of the lubricating oil being used.in the present work the effect of extraction temperature on raffinate kinematic viscosity at 100°c was studied. figures 2 and 3 show the effect of extraction temperature on raffinate viscosity for furfural and nmp extraction respectively. in general, the viscosity of raffinate produced from furfural or nmp extraction is decreased with increasing the extraction temperature and solvent to oil ratio and that may be due to the extraction of aromatic materials especially polycondensed aromatics from the lubricating oil fraction. the aromatics have the higher viscosity among the hydrocarbons that presented in raw lubricating oils and the extraction of these materials decrease their content in the produced raffinate and increase the paraffins content which has a viscosity relatively lower than that of aromatics as mentioned by kosters [8]. figures 2 and 3, clearly indicate that the extraction temperature has slightly effect on the viscosity of raffinate compared with the effect of solvent to oil ratio and the viscosity of the raffinate produced from nmp extraction is slightly lower than that produced from furfural extraction using the same operating variables, because of the higher activity and high solvent power of nmp than furfural [9]. fig. 2 effect of extraction temperature on raffinate viscosity at different solvent to oil ratio for furfural extraction 1 mixer 2 condenser 3 heater 4 thermometer 5 3 necks pyrex flask 6 oil bath 1 2 3 5 4 6 anodic polarization of anodized aluminum alloy 5052 4 ijcpe vol.10 no.2 (june 2009) fig. 3 effect of extraction temperature on raffinate viscosity at different solvent to oil ratio for nmp extraction. effect of operating variables and solvent type on raffinate viscosity index the viscosity index of lubricating oil reflects the ability of lube oil viscosity to vary with temperature. figures 4 and 5 show the effect of extraction temperature at different solvent to oil ratio on raffinate viscosity index for furfural and nmp extraction, respectively. the increase in extraction temperature will encourage the solubility of undesirable materials especially polycondensed aromatics (which reduce the viscosity index of lubricating oil) in extraction solvent. it is obvious from figures 4 and 5 that the viscosity index of lubricating oil fraction increases with increasing the extraction temperature and solvent to oil ratio.the increase of extraction temperature 10°c will increase the viscosity index one to three point for a given solvent to oil ratio using furfural and nmp as extraction solvents. the increase in raffinate viscosity index related to the reduction in naphthene – aromatic and polar aromatic content and the increase in saturates content in the produced raffinate [3]. the higher solvent power of nmp compared with furfural gave higher viscosity index using the same operating variables. fig. 4 effect of extraction temperature on raffinate viscosity index at various solvent to oil ratio for furfural extraction fig. 5 effect of extraction temperature on raffinate viscosity index at various solvent to oil ratio for nmp extraction effect of operating variables and solvent type on raffinate yield many factors controlling the operating conditions of solvent extraction. one of these important factors affecting the overall process performance is the lubricating oil yield. fig. 6 and 7 explain the effect of extraction temperature on raffinate yield at various solvent to oil ratio for furfural and nmp extraction, respectively. it appears from these figures that the yield percentage will decrease as the extraction temperature increase and solvent to oil ratio decrease. fig. 6 effect of extraction temperature on raffinate yield at various solvent to oil ratio for furfural extraction. fig. 7 effect of extraction temperature on raffinate yield at various solvent to oil ratio for nmp extraction. dr. aparel s. yaro and ala’a mishgel ali al-asade 5 ijcpe vol.10 no.2 (june 2009) the performance comparison of oil extraction by furfural and nmp the comparison was done at extraction temperature of 110°c and solvent to oil ratio in the range 1:1 to 4:1 for furfural and nmp extraction. figure 8 show the effect of increasing the solvent to oil ratio on raffinate viscosity index for furfural and nmp extraction at 110°c, while fig. 9 shows the effect of increasing solvent to oil ratio on raffinate yield for furfural and nmp extraction at 110°c. fig.8 indicates that the raffinate viscosity index produced from nmp extraction is higher than that obtained from furfural extraction.the difference in viscosity index at solvent to oil ratio 1:1 is about 10% and decreases to about 6% at solvent to oil ratio 4:1. fig.9 indicates that the raffinate yield produced from nmp extraction is higher than that obtained from furfural extraction. the difference in the yield at solvent to oil ratio 1:1 is about 25% and increases to about 44% at solvent to oil ratio 4:1. from the above mentioned discussion it may be concluded that nmp was the most efficient solvent for the extraction of lubricating oil fraction used in this study because low solvent to oil ratio can be used to produce the same raffinate viscosity index, an equivalent or higher raffinate yield obtained from nmp extraction at solvent to oil ratio higher than 1:1, low solvent toxicity, better heat stability (high boiling point). fig.8 effect of solvent to oil ratio on raffinate viscosity index for furfural and nmp extraction at 110°c fig. 9 effect of solvent to oil ratio on raffinate yield for furfural and nmp extraction at 110°c conclusions 1. the raffinate viscosity index produced from nmp extraction was higher than that produced from furfural extraction at same extraction temperatures and at the same solvent to oil ratio 2. the raffinate yield produced from nmp extraction was higher than that produced from furfural extraction at same extraction temperatures and at the same solvent to oil ratio. references 1. gary, j. h., "petroleum refining technology and economics", 3rd ed., marcel dekker inc., new york, 1994. 2. hunter, t.g., and nash, a.w., "industrial and engineering chemistry", 27(7), 836(1935). 3. kalichevsky, v.a., "petroleum engineer", 29(1), c-14(1957). 4. hobson, g.d., "modern petroleum technology" 4th ed., applied science publishers ltd, great britain, 1975. 5. soudek, m., "hydrocarbon processing", 53(12), 59 (1974). 6. " oil extraction", 2004.( internet site: www.bydesign.com). 7. nelson, w.l,"petroleum refinery engineering", 4th ed., mcgraw-hill, inc., new york, 1958. 8. bland and davidson, "petroleum processing hand book", mcgraw hill, new york, 1967. 9. sequeira, a., sherman, p.b., j. v. and mc bride, e.o., "hydrocarbon processing", 58(9), 155(1979). http://www.bydesign.com/ anodic polarization of anodized aluminum alloy 5052 6 ijcpe vol.10 no.2 (june 2009) * * nmp (n-methyl, 2, pyrrolidone) ◦ nmp14 114nmp 107 nmp◦ 101 nmp nmp االستخالص ونسبة . باالستخالصnmpالمذيب الى الزيت باستخدام مذيب الفورفزال او ال ijcpe vol.10 no.1 (march 2009) iraqi journal of chemical and petroleum engineering vol.10 no.1 (march2009) 17-22 issn: 1997-4884 kinetic study of catalytic hexane isomerization abdul halim a.k. mohammed * ,ameel m. rahman and maha al-hassani * * chemical engineering department college of engineering university of baghdad – iraq abstract the isomerization of n-hexane on platinum loaded acidic zeolite was studied at atmospheric pressure, h2/nc6 molar ratios of 1-4 and temperature range of 240-270ºc. the measured kinetic data were fitted to an equation based on the bifunctional mechanism and by using independently obtained dehydrogenation and adsorption data. the activation energies of protonation (∆hpro) and the elementary isomerization step (eact,iso) and as well as the corresponding preexponential factor were simultaneously determined. the observed values of both ∆hpro and eact,iso are in agreement with the results of quantum-chemical calculations. introduction more stringent limits on the amount of aromatics that may be included in gasoline have resulted in a renewed interest in the skeletal isomerization of nalkanes with a view to use the branched isomers as octane-enhancing components. branched isomers are more desirable because of their higher octane number. at equilibrium lower temperatures favor branched isomers; therefore there has been an effort to develop catalysts that are effective at 270ºc or less. over the past several decades the progression has been from pt/al2o3, which is active for n-hexane isomerization in the 450-500ºc range to pt/chlorinated al2o3, which is active in the 350-400ºc range and more recently to pt/h-zeolite catalysts, which are active in the 200-270ºc range. additional research has been carried on pt/sulfated zro2, pt/wox-zro2 and related materials (1). based on the earlier studies of mills et al. (2) a bifunctional mechanism for isomerization as follows; (i) dehydrogenation of alkane occurs at the metal centre (ii) the resulting alkene molecule is isomerized at an acid site and (iii) the isomerized alkene intermediate is hydrogenated at the metal centre to form the product (3). molecular hydrogen is added to the system in order to enhance isomerization selectivity and prevent deactivation of the catalyst. the bifunctional mechanism is somewhat misleading since it suggests that protonation of the alkene generates carbenium ions in the same way as occur in liquid-phase super acids (4). however, quantum chemical calculations have shown that protonation of alkenes on solid acid sites renders so-called alkoxy species as stable reaction intermediates which are bonded to the lattice by strong covalent c-o bond(s). these calculations suggest that carbenium ion like species only exist as a transition state at the (de) protonation reaction. due to the formation of strong covalent bonds, the enthalpy of protonation (∆hpro) is expected to be high; the same holds for the activation energy of the isomsrization step (eact,iso). to calculate eact,iso from kinetic measurements, eact,iso is expressed as a function of a number of parameters (5) including the apparent energy and, which is the actually measured quantity, and ∆hpro, for which nearly only quantum-chemical calculations are available. therefore values for eact,iso determined in this way may also be unreliable. university of baghdad college of engineering iraqi journal of chemical and petroleum engineering kinetic study of catalytic hexane isomerizatin 18 ijcpe vol.10 no.1 (march 2009) in conclusion, a meaningful kinetic analysis should involve an experimental determination of ∆hpro. in the present study, the kinetic data are analyzed using a rate equation based on the bifunctional mechanism, which allows for the determination of eact,iso and ∆hpro. to distinguish between the effects of adsorption and the intrinsic kinetics on the reaction rate, independent adsorption data are used. kinetic analysis if it is assumed that the isomerization step is the rate determining and conversion is so low then the reverse reaction can be neglected. it can be assumed that the dehydrogenation steps are equilibrated as reported by maha al-hassani (6) the dehydrogenation enthalpy (∆hdh) and preexponential factor of dh k ( o dh k ), were calculated from standard enthalpy and entropy of formation of n-hexane and of all branched hexane isomers; hdh ≈ hof hexane hof hexane (1) r ss dh o o hexanef o hexenef epk    (2) where, o if h ,  and o if s ,  are respectively the standard enthalpy and entropy of formation of component (i) in the gas phase (the temperature dependence of o if h ,  and o if s ,  was neglected) and  p is the standard pressure (  p =101,325 pa). the value of o if s ,  and o if h ,  of n-hexane and n-hexene were taken from the work of reference (7). although dh k refers to adsorbed phase, it is assumed that the difference between the formation enthalpy/entropy in the gas phase and the adsorbed phase is equal for nhexane and n-hexene, so that the enthalpy/entropy of dehydrogenation is equal in both phase (the calculation in eqns. [1] and [2] can be safely made, since the values for individual isomers vary by less than 10%). the adsorption parameters for zeolite were taken from studies published by eder and lercher (8, 9). the preexponential factors in units (pa-1) were calculated from henery’s constant kh (in units mmol/g.atm) measured at temperature tm using equation [3].            m adso mh xads rt h qp tk tk exp )( )( m ax … (3) where m ax q denote the maximum concentration of n-hexane in the porous crystals (in unit’s mol/kg). the value of m ax q was extracted from literature (8, 10). the net number of isomerized molecules produced per unit time per acid site is called the turnover frequency (tof) and is given by maha al-hassani (6): 1 22 2   h n dhproad h n dhadnad h n dhproads b iso p p kkk p p kkpk p p kkkk tof (4) where,kads, kdh and kpro are the equilibrium constants of, respectively adsorption, dehydrogenation, and protonation for n-hexane; kiso is the rate constant of conversion of the intermediate nhexyl alkoxide into iso-hexyl alkoxide (no distinction is made between the various isomers) ph2 is the hydrogen pressure; and pn is the n-hexane pressure. equation (4) can be linearized by taking the reciprocal expression: nproads b iso h b isoproisodhpro b iso h pkkk p kkkkkk p tof 22 111  (5) the plot of 1/tof vs. 1/pn should be linear, and since kads and kdh are known or can be determined from independent experiments, kiso and kpro can be calculated from the slope(s) and intercept ( i ): dhadshadsh h iso kkspksip p k   22 2 (6) abdul halim a.k. mohammed, ameel m. rahman and maha al-hassani 19 ijcpe vol.10 no.1 (march 2009) 122  dh h dhads h pro k p kks pi k (7) by determining kiso and kpro as a function of temperature and plotting ln kiso and ln kpro vs. the reciprocal temperature, respectively, eact, iso and ∆hpro can be obtained. experimental and materials n-hexane supplied by bdh with 99% purity was used as a feedstock for isomerization experiments. hyzeolite (cbv 600) catalyst powder was supplied from zeolyst international and used as a support for catalyst preparation. 100 g of hy zeolite powder was mixed with 30% montmorillonite clay as binder as suggested by murry (11). the resulting mixture was mixed with water to form a paste. an extrudates with 0.3 cm were formulated and dried over night at 100ºc, then 0.3 wt%pt/hy-zeolite was prepared by impregnation method with a proper solution of hexachloroplatinic acid. the impregnated extrudates were dried at 110ºc then calcinated at 300ºc for 3 hours in furnaces with dry air (12). the calcinated catalyst was then reduced with hydrogen at 350ºc for 3 hours (13). procedure and equipments the catalytic unit performance tests were carried out in a continuous fixed bed reaction unit. the reactor was a carbon steel tube with an outside diameter of 1.9 cm, 2 mm thick and 80 cm length. 0.3wt%pt/hyzeolite catalyst was charged between two layers of inert materials (glass balls). the catalytic reactions were carried out in the temperature range of 240270ºc, lhsv of 1-4 h-1, h2/nc6 mole ratio of 1-3 and atmospheric pressure. n-hexane partial pressure was kept at 0.28 bar while hydrogen pressure varied between 0.29-0.56 bar using nitrogen as a makeup gas. the nitrogen pressure varied between 0.16-0.45 bar to obtain the final atmospheric reaction pressure. liquid products were trapped by condenser at -5ºc, collected periodically and analyzed by using gas chromatography. the gas chromatography model 438aa-vsa supplied by agilent technologies company was used for the analysis. this device equipped with column of 0.25mm diameter 100m length and fid detector. results and discussion the adsorption parameters were calculated using the available thermodynamics data (9-14) using equation [3]. these results are tabulated in table (1). table 1, adsorption parameters. tx(k) kads(tx)(pa -1 ) 513 1.60x10 -5 523 1.31 x10 -5 533 1.08 x10 -5 543 9.08 x10 -6 fig.1: shows the plot of lnkads vs. reciprocal temperature for ∆hads calculation ∆hads of 44.2 kj/mol was obtained from figure 2. since the heat of adsorption is exothermic, the adsorption-equilibrium constant kads decreases with increasing temperature. the preexponential factor of adsorption equilibrium has a value of 5.08×10-10pa-1 the dehydrogenation parameters were presented in table (2) using equation [1] and equation [2]. which ∆hdh equals to 118kj/mol (4). since the dehydrogenation is endothermic process, the dehydrogenation-equilibrium constant kdh increases with increasing temperature. the preexponential factor of dehydrogenation reaction has a values of 3.868×1010 pa. this values are agreed well with the reported results (4, 15, 16). table 2, dehydrogenation parameters. tx (k) kdh(tx)(pa) 513 0.3733 523 0.63 533 1.05 543 1.72 kinetic study of catalytic hexane isomerizatin 20 ijcpe vol.10 no.1 (march 2009) catalyst activity the conversion rates of n-hexane were calculated from the slops of conversion isotherms represents as a function of space time which expressed by gram catalyst per moles of n-hexane feed per second, (gcats/mol). apparent activation energies were determined from temperature dependence of the rates of the total conversion, according to the arrhenius equation (17). according to the differential method the derivative 6 6 nc nc wf dx evaluated from experimental data was used to obtain the reaction rate 6nc r . the obtained overall rate of reaction is normalized to the number of acid sites. the values of the 6nc r were used for tof calculations is generally proportional to the catalyst concentration and surface area of the catalyst, so a turnover frequency (tof) as number of moles reactant converted per mole of brönsted acid sites per unit time must be calculated. figure 2 is used for the simultaneous determination of kiso and kpro from slopes and intercepts of 1/tof vs. 1/pnc6 lines plots according to equation (5). table (3) shows the values of kiso and kpro estimated at ph2=0.57bar and pnc6 ranging from 0.14-0.42bar. fig.2 experimental reciprocal rate equation plots obtained for n-hexane isomerization. table 3 isomerization and protonation parameters. tx (k) kiso (sec -1 ) kpro (-) 513 1.82 x10 -2 9.84 x10 +5 523 2.19 x10 -2 6.41 x10 +5 533 2.67 x10 -2 5.75 x10 +5 543 9.67 x10 -2 3.24 x10 +5 a high value of kpro indicates that the olefin protonation equilibrium entirely displaced toward the formation of carbenium ion as reported by riberiro and gauw et al. (4). the measured protonation energy -74kj/mol from fig.3 is agree well with those obtained by of quantum-chemical method of kazansky et al. (19) and viruela et al. (20). fig.3, plot of lnkpro vs. reciprocal temperature. the value of eact,iso was 119.7kj/mol obtained from fig.4. the preexponential factor of protonation and isomerization reaction have a value 125.2 and 2.2×10 11 , respectively and within the experimental temperature range of 240-270ºc, the variation in the rate coefficient of branching rearrangement was relatively small, leading to the conclusion that observed differences in turnover frequencies for the various catalysts was predominantly caused by differences in the adsorption constants. fig.4 plot of lnkiso vs. reciprocal temperature. abdul halim a.k. mohammed, ameel m. rahman and maha al-hassani 21 ijcpe vol.10 no.1 (march 2009) it was possible to simultaneously determined the energy of protonation and energy of branching rearrangement as well as correspondingly preexponentioal factor by fitting the measured kinetic data to an equation based on the bifunctional mechanism and using independency the obtained dehydrogenation and adsorption data as follows:  rtk iso /107.119exp102.2 311  … (5)  rtk ads /102.44exp1008.5 310   … (6)  rtk dh /100.118exp1086.3 310  … (7)  rtk pr /1079exp2.125 3  … (8) consider these terms in equation (4), the overall rate equation per acid sites was obtained by equation 9:                           2h6nc 33 2h6nc 3 6nc 310 2h6nc 314 p/prt/10x5exp10x5.2 p/prt/10x8.73exp6.19 prt/10x2.44exp5101 p/prt/10x5.114exp10x4.5 tof (9) in the case of a low pressure of n-hexane the overall rate equation per acid sites can be approximated by:       2h6nc 33 2h6nc 314 p/prt/10x79exp10x5.21 p/prt/10x5.114exp10x4.5 tof    (10) conclusions by measuring the rate of the n-hexane hydroisomerization reaction on pt/hy-zeolite as a function of n-hexane pressure and fitting the results to a rate equation on the bifunctoinal isomerization scheme of weisz, it was possible to simultaneously determine the equilibrium constant of n-hexane protonation and the rate of constant of isomerization of the resulting n-hexyl alkoxides. by repeating this procedure at different temperatures, the protonation energy ∆hpro, the activation energy of isomerization eact,iso and corresponding preexponential factor could be determined. the measured values of ∆hpro equal to -79 kj/mol whereas the value of eact,iso equal to 119.7 kj/mol. these values are agree well with the results of quantumchemical calculations. references 1. gates, b.c., katzer, j.r and schuit, g.ca., “chemistry of catalytic process”, p.184. mcgraw hill, chemical engineering series, new york, 1979. 2. mills, g.a., heinemann, h., milliken, t.h. and oblad, a.g., ind. eng. chem. 45, 134, (1953). 3. hon yue chu, michaal, p. roynek and jack, h.l., “selected isomerization of hexane over pt/hbeta zeolite; is the classical mechanism correct?”, j. cat., 178, 325-362, (1998). 4. gauw, f.j.m.m., grandell, j. and santen r.a., “intrinsic kinetics of n-hexane hydroisomer catalysed by platinum loaded solid acid catalysts”, j. catal., 206, 295-304, (2002). 5. kazansky, v.b., frash, m.v. and van santen, app. cat., a. gen., 146, 225, (1996). 6. maha al-hasani, “kinetic study of n-hexane isomerization”, m.sc. thesis, baghdad university, 2007. 7. rossini, f.d., pitzer, k.s., arnett, r.l., brawn, (1953) “physical and thermodynamics properties of hydrocarbons and related compounds”, api project no. 44, carnegire press, pittsburgh. 8. eder e., and lercher j.a., j. phys. chem. b: 101, 1273-1278 (1997). 9. eder f., stockenhuber m., and lercher j.a., j. phys. chem. b: 101, 5411-5419 (1997). 10. denayer j.f., gino v., baron, j. phys. chem. b: 102, 3077-3081 (1998). 11. murray brendan, process for “isomerization linear olefins to iso-olefins”, us patent, 5648584, (1997). 12. riberiro, f., marcilly, c., and guisnet, m., hydroisomerization of n-hexane on platinum zeolite”, j. cat., 78, 267-273, (1982). kinetic study of catalytic hexane isomerizatin 22 ijcpe vol.10 no.1 (march 2009) 13. masologites., gates, “method of treating a used pt group alumina catalyst with a metal promoter”, us patent, 4070306, 1987. 14. denayer j.f., baron v., gina, vanbustsel a., pierre a., jacobs johan a., martens, chem. eng. science, 54, 3553-3561 (1999). 15. bokhoven j.a., tramp m., koningsbarger j.t., miller and pieters j.a.z., lercher j.a., williams and kung, j. catal., 202, 129-140 (2001). 16. ribeiro f., marcilly c., and guisnet j. catal. 78, 267274 (1982). 17. fogler h. scott, “element of chemical reaction engineering” 2 nd edition englewood cliffs, new jersey, 1994. 18. viruelamartin p., zicovichwilson c.m., corma, "ab initio molecular orbital calculation of the protonation reaction of propelene and isobutene by acidic oh group " j. phys-chem 97, 13713(1993). 19. kazanasky v.b., frash m.v. and van santen, r.a., " quantum chemical study of isobutene cracking on zeolite", appl. catal.a:general 146,225 (1996). دراسة حركية تفاعل ازمرة الحفاز للهكسان االعتيادي ايٍم رحًٍ و يها انحسًُ, عثذ انحهٍى عثذ انكرٌى * انعراق-تغذادقسى انهُذسح انكًٍاوٌح – كهٍح انهُذسح –جايعح تغذاد * أجرٌد . تطرٌقح انرحًٍم انرطة واسرخذيد الزيرج انهكساٌ االعرٍادي 0.3wt%pt/hy-zeolite ذى ذحضٍر انعايم انًساعذ -240انرجارب انًخرثرٌح تضغط جىي فً يُظىيح رٌادٌح ذحرىي عهى يفاعم رو انحشىج انثاترح و تذرجاخ حرارٌح ذراوحد تٍٍ 270 º سا3-1 و و سرع فراغٍح -1 . 4-1و انُسة انًىنٍح نههٍذروجٍٍ إنى انهكساٌ االعرٍادي اسرخذيد انثٍاَاخ انًرىفرج فً األدتٍاخ نحساب . ذى اشرقاق انًعادنح انعايح نسرعح انرفاعم تاالعرًاد عهى يٍكاٍَكٍح ثُائٍح انذانح . ثىاتد انرىازٌ نعًهٍح االيرصاص وإزانح انهٍذروجٍٍ يىل / كٍهى جىل79-يىل فً حٍٍ قًٍح اَثانثٍح ذفاعم ذىنٍذ انثروذىَاخ / كٍهى جىل119.7اٌ قًٍح طاقح ذُشٍط نرفاعم االزيرج هً : ًٌكٍ انرعثٍر عٍ انًعادنح انعايح نسرعح انرفاعم كانرانً.                           26 33 26 3 6 310 26 314 //105exp105.2 //108.73exp6.19 /102.44exp1051 //105.114exp104.5 hnc hnc nc hnc pprt pprt prt pprt tof available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.20 no.2 (june 2019) 33 – 40 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: muna a. rahi , email: munaaziz21@gmail.com, name: ayad a. h. faisal, email: ayadabedalhamzafaisal@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. performance of subsurface flow constructed wetland systems in the treatment of al-rustumia municipal wastewater using continuous loading feed muna a. rahi and ayad a. h. faisal university of baghdad abstract this study aimed at comparing the performance of vertical, horizontal and hybrid subsurface flow systems in secondary treatment for the effluent wastewater from the primary basins at al-rustumia wastewater treatment plant, baghdad, iraq. the treatments were monitored for six weeks while the testsduration were from 4 to 12 september 2018 under continuous wastewater feeding for chemical oxygen demand (cod), total suspended solid (tss),ammonia-nitrogen(nh4-n) and phosphate (po4-p) in comparison with fao and usepa standards for effluent discharge to evaluate the suitability of treated water for irrigation purposes. among the systems planted with phragmites australia, the hybrid subsurface flow system which consisted of vertical unit followed by horizontal one, considerably removed the pollutants more efficiently than the single operated systems. the planted hybrid subsurface flow wetland system was achieved the highest removal with a mean removal rate of cod,tss, nh4-n, and po4-pat 99.3, 83.2,67.4 and 53% respectively and these percentages were decreased in the other systems. the results proved that the planted vertical subsurface flow unit can be removed the cod, tss, nh4-n and po4-pwith values of 93, 71.1, 43.3 and 30.7%, respectively while the achieved removals by horizontal subsurface flow unit of 99, 74.3, 54.5 and 20.3%, respectively. the planted horizontal subsurface flow wetland, however, showed a good efficacy for all parameters in the treatment process except for po4-p when it is compared with vertical system, however, there is a clear increase in the no3-n effluent concentration for all treatment units. keywords: constructed wetlands, subsurface flow, wastewater treatment, wastewater parameters received on 06/03/2019, accepted on 14/04/2019, published on 30/06/1029 https://doi.org/10.31699/ijcpe.2019.2.5 1introduction the freshwater resources are becoming inadequate to fulfill demand with the growing global population, leading to a global challenge of freshwater scarcity. in its most recent annual risk report, the world economic forum lists water crisis as the massive global risk in terms of potential impact ‎[1]. many countries facing water scarcity during the last four decades, most of which are developing countries, are expected to increase to 34 by the year 2025 ‎[2]. due to the rapid growth of population and economic growth in iraq, there is a serious water shortage problem through the increasing of demand on limited freshwater supplies and increased in wastewater volume discharged. around the world, treated wastewater appears to be the only freshwater resource that is increasing as other sources are dwindling ‎[3]. direct disposal of untreated wastewater to water bodies and land has a negative impact on human health, then sufficient wastewater treatment for reuse will hence be a feasible option in ameliorating water scarcity challenge and environmental degradation, moreover, the treated wastewater may be formed a non-conventional water sources for satisfying the increase in demand rate for freshwater. in iraq, there are eleven major wastewater treatment plants with a total capacity of 650000 m 3 /day and usually, they are located near the river banks of euphrates, tigris, diala, kahla, diwaniyah, husseinya and shatt al-basrah. the adopted treatment scheme processes in the plants consisted of traditional steps and can be arranged as preliminary, primary, and secondary treatment systems ‎[4]. these systems required many requirements such as facilities, sanitary collection, as well as treatment and disposal of wastewater to decrease and/or remove the concentration of familiar components like bod5, cod, total suspended solids (tss), and nutrients to ensure that the final effluents will not cause additional pollution. the main advantages of those techniques are the best control on the treatment process and, also, the required area for construction of this project can be acceptable. traditionally, the spread of the rural population in many villages and the high cost of wastewater conveyance system and treatment beside their own properties and conditions would require decentralized wastewater treatment plant. https://doi.org/10.31699/ijcpe.2019.2.5 m. a. rahi and a. a. h. faisal / iraqi journal of chemical and petroleum engineering 20,2 (2019) 33 40 43 therefore, these technologies must be robust and capable of operating with minimal maintenance or supervision are of great value for the local population and are expected to be the only feasible alternative for conventional wastewater treatment ‎[5]. constructed wetlands (cws) have developed rapidly over the past decades and recognized as quick solutions or alternatives to conventional mechanical treatment systems in many countries particularly those located in arid and semi-arid areas due to their uncomplicated construction of local materials and easiness for uneven flow of wastewater as well as simple operational and maintenance requirements ‎[6]. cws are artificial wastewater treatment systems designed into engineered systems to treat wastewater by removing pollutants from contaminated water by using natural processes that occur in natural wetlands ‎[7]. in addition, their natural form enables easy incorporation into the existing landscape ‎[8]. cws can be classified according to water flow into surface and subsurface flow systems, which are currently, the most used ‎[9]. water did not surpass the upper surface of the stone bed, which preferred to surface flow cws for concerns about human contact with untreated wastewater, mosquito and odour control ‎[10]. the vertical flow (vf) that is provided aerobic conditions, offer very efficient mineralization of organic matter and nitrification (the conversion of ammonium in wastewater to nitrates by organism oxidation as a metabolic process (aerobic process) using nitosomonas bacteria, while nitrite converts into nitrogen by the denitrification in anaerobic process. whereas horizontal flow (hf) usually preferred to other cw types when anaerobic processes for treating wastewater are sufficient, hf is most widely used for wastewater treatment, but vf systems are getting hold of popularity ‎[11]. the compensation of various systems or several types of cws arranged in a staged manner to form a hybrid system towards achieving better pollutants removal and treatment performance especially with respect to the nutrients components ‎[12]. the key pollutants that affect the selection of the treatment process are suspended solids, organic material (bod5, cod), ammonia and organic nitrogen, phosphorus, in addition to the pathogenic organ, viruses, bacteria, protozoan, and helminth eggs ‎[13]. the degradation and mineralization of organic matter occurs in both the bed substrate and the biofilms on reed plants ‎[14], vegetation has a minor function in the transformation and mineralization of nutrients and organic pollutants where the roots of the plants can be provided a bulky surface area for attachment of microorganisms that played the main role of organics degradation ‎[15]. plants roots also prevent wastewater from taking preferential paths in the substrate that can be affected on the hydraulic retention time in the wetlands ‎[16]. in the subsurface cw systems, media material is an important factor because it could avoid clogging to ensure a sufficient hydraulic conductivity ‎[17]. this study aims to investigate the ability of different cws systems namely; vertical, horizontal and hybrid subsurface flow configurations in the continuous mode of loading feed for reclamation of the real municipal wastewater for irrigation purposes. this work is a part of the study conducted on the various systems of the cws under batch and continuous modes of operation to test their feasibility in the treatment process. 2experimental work 2.1. study site description al-rustumia ; t i n seen in fig. 1. this project is serving the eastern areas of the army channel; precisely, the new baghdad, first and second sadar, al-ghadir and al-shaab regions ‎[18]. the choice of this location for constructing the experimental facility of the present study was related with a number of considerations such as; the similarity in the objectives and environmental circumstances between the sanitary wastewater treatment plant (wwtp) and the constructed wetland, as well as the presence of laboratory building for achieving the planned measurements. in addition, the facility is unique in the fact that it is located adjacent to the wastewater treatment plant, enabling all of the pilot-scale systems to receive the same municipal wastewater with required quantities through the operation process. raw wastewater, supplied to the units of the constructed wetlands, was taken from the effluent collection point of the three primary basins to ensure the amounts of the suspended solids as low as possible. fig. 1. the cw system location within alrustumia wastewater treatment plant, baghdad m. a. rahi and a. a. h. faisal / iraqi journal of chemical and petroleum engineering 20,2 (2019) 33 40 43 2.2. experimental design and layout the treatment systems consist of vertical, horizontal, and hybrid subsurface flow wetland system planted with phragmites australia. the wetland units (fig. 2) included one planted horizontal flow (hfp) system, one planted vertical flow (vfp) system and one planted hybrid system which composed of vertical flow unit followed by horizontal flow (vfp-hfp). all the cw units have the same size (length of 2.85m, width of 1.2m and depth of 0.8m), shape, flat bottom and equal aspect ratio (length to width). the units were manufactured from steel structures that fitted with fiberglass sheets of 10 mm thick. this is very important to avoid any chemical reactions between the steel structure and wastewater, prevent uncontrolled filtration and provide an environment that identical to the conditions of soil. the units were provided with openings located at the bottom for backwash cleaning and maintenance purposes. fig. 2. the pilot-scale cw units manufactured in the present study within al-rustumia wastewater treatment plant/ the third expansion project the design of cw units used in this study was the same as the pilot-scale treatment system of langenreichenbach ecotechnology research facility installed in germany ‎[19]. as seen in fig. 3, the filling materials in vfp were arranged in four layers according to the size of the particles. these layers are organized from the bottom of the basin as follows; 0.15 m coarse gravel of 16-40 mm, 0.15 m medium gravel of 8-16 mm, 0.2 m fine gravel of 4-8 mm, and finally 10 cm coarse sand of 1-3 mm..in order to provide good aeration through the vfp unit, the number of techniques was used to supply oxygen in addition to that oxygen afforded via the roots of plants e.g., wastewater was injected from the top of the bed through the system of pipes called distribution network which consisted of 2-in diameter polypropylene pipes. four pipes installed along the length of the bed and two lateral pipes located at 5 cm above the packed bed, the openings with a diameter of 13 mm were chosen with uniform peripheral distribution spacing equal to 10 cm of openings around each pipe. this location will provide a good contact with air for more air supplied into the substrate, a collection network which consisted of seven perforated pipes installed laterally with two longitudinal manifolds used to collect the percolated water, the diameter of the pipes in the collection network is similar to that of distribution network with diameter of openings equal to 15 mm and they spaced at distances equal to 10 cm. the vfp unit is also provided with aeration tube to equip the system with additional ventilation. the hfp was filled with medium gravel (grain size 8-16 mm) up to a height of 0.6 m. two compartments of 0.30 m at the inflow and outflow points were filled with coarse gravel (grain size 40-60 mm) to protect and avoid potential clogging of the inflow/outflow pipes with time. the wastewater was supplied slowly to the bed of cw through the perforated polypropylene pipe of 100 mm diameter that placed in the inlet zone at the top of coarse gravel compartment; subsequently, the water was collected by another perforated pipe of 100 mm diameter, which placed in the bottom of the outlet zone. from the first stage of a plantation, the units were fed by intermediate loading with a hydraulic retention time of 5 days till the middle of august 2018. when one year of the plantation was passing, a continuous feeding operation was started where the cws were operated with a wastewater flow rate of 450l.d -1 i.e. 0.131 m/d as a hydraulic loading rate. there was no clogging through the beds along with the duration of treatment processes. fig. 3. schematic representation of the pilot-scale wastewater treatment plant using subsurface flow cws 2.3. vegetation phragmites australis, (common reed) as a native plant that is widely available in vast quantities through the environment of iraq especially in the natural marshes located at the southern regions having the following properties m. a. rahi and a. a. h. faisal / iraqi journal of chemical and petroleum engineering 20,2 (2019) 33 40 43  bearing the environment of immersion, can withstand high levels of salinity and pollutants.  having a large exterior surface that are provided to the bacteria, yeast, and fungi that required for degradation of contaminants.  supplying a high level of oxygen, to ensure aerobic processes in the treatment zone, and have deep roots.  living all around the year.  fast growing and spreading. also, the very extensive root system creates channels for the water to pass through and provide the means for the secondary restructuring of the reed bed substrate system. phragmites australis was selected for the plantation process in constructed wetlands furthermore its availability within the primary and aeration tanks of alrustumia treatment plant ‎[20]. this means that the choice of the reed plant may be a suitable decision because it will reduce the required maintenance for mentioned tanks and the plant is already acclimated with the same type of wastewater that will treat in the present experimental facility. during the second half of september 2017, healthy plants were removed from the aeration beds and trimmed to a height of 0.15 cm, planted into the experimental units to ensure rapid growth as mentioned in [9] with a density of 8 plants/m 2 which comparable with ‎[21] ‎[21], ‎[22] 2.4. water sampling and quality analysis the water samples were collected at the inlet and outlets of the planted cws using 0.5 l clean plastic bottles. three times a week, sampling for each treatment for 2 weeks from 2 nd september to 15 th september 2018 was done in duplicates. the samples were transported directly to the laboratory. water quality parameters (i.e., cod, nh4-n and po4) were determined using hach lang spectrophotometer. tss was measured according to 2540d, total suspended solids dirt (mg/100ml) at 103-105 o c by using gravimetric filtration (0.45µm pore diameter filter). the tests were according to the standard methods for the examination of water and wastewater ‎[23]. all tests were done in the chemical laboratory of al-rustumia wastewater treatment plant. 2.5. removal efficiencies of pollutants the removal efficiencies of the chosen wastewater parameters were calculated according to equation: 1. ( ) (1) where: ci = influent concentration (mg/l) ce= effluent concentration (mg/l) 3results and discussion 3.1. phragmites australis monitoring the gravel that used for building purposes was chosen as the bed material for phragmites australis implementation, their densities have been increased dramatically within all the vegetated cw units from 8 plants/m 2 at plantation in september 2017 to reach 108plants/m 2 after 9 months from plantation process and then to reach 112-115 plants/m 2 in september 2018. their average height was more than 1.5 m. this type of reed has good growth ability and, during the summer season, it seems that the foliage branches of common reeds suffered and looked to be yellow and dry. the optical condition may be due to temperature rising which was around 50⁰c or because of pollutants accumulation in plant tissues. previous studies pointed out that this problem could be solved by trimming stems and added them to the experimental unit for nature reproduces ‎[8]. the monitoring of the treatment process in the present work was begun in the 2 september until 12 september 2018 where the density of the plants reached to the stable state with a value equal to 112-115 plants/m 2 . 3.2. organic materials (cod) removal effluent and influent cod concentrations for all the wetland units were measured during the monitoring period and plotted in fig. 4. the mean influent cod concentration was 321.5mg/l. among the three cws units, the hybrid system can be caused a significant reduction in the effluent cod where the lowest mean value of 2.7 mg/l followed by the hfp of 4.2 mg/l and vfp with the value of 17.7 mg/l. higher cod removal rates might be related to physical processes such as filtration, sedimentation, and adsorption that can be achieved in cw units in addition to biological degradation. the more efficient treatment by the hybrid system could be recognized from high removal efficiencies. this can be attributed to the passing of wastewater through vfp and, then, hfp systems where this configuration can be optimized between the advantages and disadvantages of vertical and horizontal units when operated as a single system and the result will be the high efficiency in the treatment process. the standards of france for organic matters present in treated wastewater that could be reused for irrigation purposes, represented by cod concentration <60 mg/l for all crops except those consumed raw food crops ‎[24], consequently, each effluent of the three cws is within the accepted france standards and also the present results are satisfied with acceptable limits of usepa (2006). m. a. rahi and a. a. h. faisal / iraqi journal of chemical and petroleum engineering 20,2 (2019) 33 40 43 the aerobic conditions of the vf wetlands support organics, tkn and nh4-n removals, but any change in operational improvements are considered critical for vf wetlands ‎[25], so as the system became always saturated, as a result the environment of the microorganisms within the vfp unit has changed, hence, the hfp was best than the vfp in organic material removal as shown in the same figure. the previous study such as ‎[26] pointed out that, in the continuously loaded reactor, the constant addition of wastewater created laminar flow inside the media that could have inhibited homogeneous mixing. the authors reported that rapid addition of substantial wastewater amount in the intermittently loaded reactor resulted in forcing the flow of wastewater through aerobic-anaerobic conditions due to water turbulence inside the media which enhanced the biodegradation of organic matters in the vfp, where this consequence conditions facilitated the growth and proliferation of aerobic microbes. fig. 4. cod concentrations and removal values in vfp, hfp and hybrid wetland systems 3.3. nutrients removal the nitrogen compounds are of importance beside the organic materials; the inorganic forms of nitrogen (i.e. nh4-n and no3-n) were measured within the cws treatment units as an indicator of nutrients present in treated wastewater during the observation period. the nh4-n and no3-n concentrations in influent and effluent for all the units are presented in fig. 5. the influent concentration of nh4-n was 59.5mg/l, while the effluent concentrations for hybrid cw units was 15.7 mg/l followed by the hfp and vfp with values of 23.7 and 28.8 mg/l respectively. the standards of fao for nh4-n concentration in treated wastewater that could be reused for irrigation purposes ranged from 5-30 mg/l [2], which mean that all cws treatment units achieved an acceptable percentage of treatment so that ammonianitrogen concentrations in the treated water were acceptable with these standards. the best removal of nh4-n was achieved in the hybrid unit with mean value of 67.4% that could be linked to the long contact time that allowed simultaneous organic as well as nitrogen removal via anaerobic microbial route and microbiological processes in the gravel used as substrate where these results are consistent with observations of study presented by ‎[27]. the mean value of nh4-n removal within the hfp was 54.5% while the vfp removal rate can be reached to 43.3% and this may be indicated to the lack of sufficient oxygen that hindered the nitrification route. since the unit is always saturated with wastewater due to the continuous feeding, anaerobic conditions will be predominant, in that case, better aeration must attain, to enhance the nitrification process and subsequently, the formed nitrates are easily utilized by the plants. fig. 6 showed that the influent concentration of no3-n was 1.6 mg/l, while the mean effluent concentrations were 1.7, 2.1 and 3.8 mg/l for hfp, hybrid and vfp respectively. the no3-n limitation illustrated by fao 2003 was in the range (0-5 mg/l) to reuse the treated wastewater in agricultural irrigation ‎[2], and then the effluents from all units were within these limits. the decrease in nh4-n combined with the nonappearance of increase in no3-n indicates that the system conditions allowed for some denitrification. this process is only happened at organic availability in anaerobic or anoxic conditions, it occurred at a rate similar to nitrification so that there appears to be no change in no3-n concentration. this situation appeared in hf and hybrid systems; on the contrary, the no3-n concentrations have been increased in the vfp, indicating for some restricted or limited conditions for denitrification process. this can be attributed either to the distribution method of water through the distribution network or due to the presence of the aeration pipe. fig. 5. nh4-n concentrations and removal values in vfp, hfp and hybrid wetland systems fig. 6. no3-n concentrations in vfp, hfp and hybrid wetland systems m. a. rahi and a. a. h. faisal / iraqi journal of chemical and petroleum engineering 20,2 (2019) 33 40 43 3.4. ortho phosphate-phosphorous removal despite its role as a fundamental nutrient for plants in aquatic ecosystems, the excessive po4-p concentrations could cause eutrophication and algae growth in the water body ‎[28]. fig. 7 presents the phosphate phosphorous (po4-p) concentrations in the effluent and influent water for systems under consideration during the observation period. the lowest values of po4-pconcentrations can be recognized in the hybrid system in comparison with other systems where the mean removal efficiency equal to 53% and this value was decreased in the vfp and hfp to become 30.7 and 20.2% respectively. this means that the mean values of effluent concentrations for po4-p were 2.4, 2.8 and 1.6 mg/l for vfp, hfp and hybrid systems respectively, while the influent concentration equal to 3.5 mg/l. the presence of plants in all the cw units could further polish the wastewater as stated by ‎[28] so phosphate concentrations decreased in the planted units. however, other study ‎[29] illustrated that phosphorus removal was approximately similar in planted and unplanted units, as media controlled phosphorus removal route. also additional study stated that although orthophosphates can be removed by chemical precipitation in the filter materials, well-heeled with ca/fe/al contents and can be degraded biologically; polyphosphates often undergo hydrolysis process but the typical removal of phosphorus observed in subsurface flow wetlands is generally influenced by media chemical adsorption route and physical precipitation of ions [30]. the difference in the removal efficiencies between the systems might refer to the larger surface area of vfp media due to different layers that might offer best adsorption surfaces comparing to hfp. according to fao (2003), the total phosphorus allowed in wastewater to reuse safely for agriculture purposes was specified between 0-2 mg/l ‎[2], thus only the hybrid unit is within this standard while the vfp and hfp need more improvement to increase their removal rate. fig. 7. po4-p concentrations and removal values in vfp, hfp and hybrid wetland systems 3.5. total suspended solids removal total suspended solid (tss) in the influent and effluent concentrations for all systems during operation period can be plotted in fig. 8. the results proved that the hybrid system plays a significant role in the treatment of the wastewater where the mean effluent concentration of tss equal to 12.8 mg/l with highest removal efficiency reached to the 85%. this figure signified that the effluent concentration of tss from vfp was higher than that of hfp with mean values equal to 22.2 and 19.7 mg/l respectively were the identical achieved removal efficiencies of 71.1 and 74.4%. the best performance of the hybrid system could be attributed to the longer wastewater retention in the substrate in comparison with other systems due to the presence of two types of cw. also, the processes of sedimentation and filtration might be enhanced due to the reed roots that have slowed down the velocity of wastewater through the media thereby increasing the retention time which consequently improved removal level. fig. 8. tss concentrations and removal values in vfp, hfp and hybrid wetland systems 4conclusions the present results proved that the constructed wetlands of different configurations are effective in the removal of most pollutants in the real municipal wastewater. among the subsurface flow wetland systems planted with the common reed, the hybrid system attained significantly the highest removal of cod, tss, nh4-n, and po4-p with values of 99.3, 83.2,67.4 and 53% respectively, compared to the horizontal and the vertical subsurface flow systems. the horizontal subsurface flow system also performed significantly better in cod, nh4-n and tss removal compared to vertical system except in po4-p removal, this might due to the changing of operation condition which has a significant effect on the performance of the vertical system. overall, through the continuous loading the hybrid system planted with phragmites australia being the best in pollutants removal and it can be used as a substitute of the secondary treatment in the traditional municipal wastewater treatment plant. m. a. rahi and a. a. h. faisal / iraqi journal of chemical and petroleum engineering 20,2 (2019) 33 40 43 acknowledgments we are sincerely grateful to alrustumia wastewater treatment plant staff for allowing us to set up the experimental units at their wastewater treatment plant site. thanks also to the environmental engineering department, university of baghdad for offering us the technical support. references [1] h k , a m k m (20 ) “f u b people facing severe ” s advances, 2(2). [2] almuktar, s., abed, s. n., and scholz, m. (2018a). “w ub u u : ” environmental science and pollution research, 25(24), 23595– 23623. [3] abdul-f , m a (20 ) “r u wastewater for irrigation: conceptual and basic design elem ” i j u c p u engineering vol 12 no 1 (2011). [4] a u ,(2008) “i m e in figures – aquastat su 2008”, r , 2008. [5] li, j (20 0) “a d z wastewatertreatment in small towns and villages of c ” a 20 0: ub d of energy and environment division of environmental systems analysis chalmers university of technology göteborg, sweden [6] v z , j (20 0) “c u w w t ’, w 20 0, 2( ), 0-549; [7] v z , j (20 ) “c u : f ” environmental science and technology. 45 (1), 61– 69. [8] stefanakis, a. i., and tsihrintzis, v. a. (2009). “p -scale vertical flow constructed wetlands treating simulated municipal wastewater: u ” d ination. 248(1–3), 753-770. [9] stefanakis, a., akratos, c. s., and tsihrintzis, v. a. (20 ) “v f c u w ” edition, eco-engineering systems for wastewater and sludge treatment, elsevier science. [10] wu, s., kuschk, p., brix, h., vymazal, j., and d , r (20 ) “d u d wetlands inperformance intensifications for wastewater treatment: a nitrogen and organic matter ” w r , , 0-55. [11] v z , j (20 ) “t u constructed wetlands in nutrient cycling and retention ” [12] taheriyoun, m., and rad, m. (2017). “s u u ” eu w , 58, 135-141. [13] k a ab , z (20 ) “i nutrient removal in constructed wetland wastewater t ”, journal of petroleum research and studies, vol. 136 no. 3, pp. 74–87, 2011. [14] kouki, s., m’ , f , s , n , ï , s , h , a (2009) “p u wetland treating domestic wastewaters during a ” d 2 ( –3), 452467. [15] shama, s., perveen, i., sumera, s. ahmed, n. a , n , s (20 ) “a u macrophytes influence on wastewater treatment through subsurface flow hybri u ”, ecological engineering., vol. 81, pp. 62–69, 2015. [16] sayadi, m. h., kargar, r., doosti, m. r. and s , h (20 2) “h b u : a ”, proceedings of the international academy of ecology and environmental sciences, 2012, 2(4):204-222 . [17] r k i ib (20 ), “u a rustamiyah sewage treatment plant through experimental and theoretical analysis of membrane f u ” i j u c p u engineering, vol 18 no 2 (2017). [18] nivala, j., headley, t., wallace, s., bernhard, k., brix, h., afferden, m. van, and arno, r. (2013). “c u  : t design and construction of the ecotechnology research l b , g ” e engineering, elsevier b.v., 61, 527–543. [19] alanbari m. ali and muter, m. salim (2018) “e u e ntal sustainability indicators of northern rustimeh wastewater treatment plant in baghdad, iraq, using simapro7.1 p ”, journal of engineering and sustainable development, vol.22 , no. 05, pp. 188–199, 2018. [20] toscano, a., langergraber, g., consoli, s., and c , g l (2009) “m u a pilot-scale two-stage subsurface flow constructed ” e e , (2), 28 –289. [21] borin, m., politeo, m., and stefani, g. de. (20 ) “p b u ” e e , (51), 229– 236. [22] apha , a., water environment federation (20 2) “s ” u , w dc, usa. [23] jeong, h., kim, h., and jang, t. (2016). “i water quality standards for indirect wastewater reuse in agriculture: a contribution toward u b u s u k ” w (switzerland), 8(4), 169-187. [24] zhao, y.q., babatunde, a.o., hu, y.s., kumar, j l g , z , x h (20 ) “p -scale demonstration of a novel alum sludge-based constructed wetland system for enhanced wastewater ” p , ( ), 2 8–283. https://advances.sciencemag.org/content/2/2/e1500323?utm_source=rss&utm_medium=rss https://advances.sciencemag.org/content/2/2/e1500323?utm_source=rss&utm_medium=rss https://advances.sciencemag.org/content/2/2/e1500323?utm_source=rss&utm_medium=rss https://www.ncbi.nlm.nih.gov/pubmed/29959736. https://www.ncbi.nlm.nih.gov/pubmed/29959736. https://www.ncbi.nlm.nih.gov/pubmed/29959736. https://www.ncbi.nlm.nih.gov/pubmed/29959736. https://www.ncbi.nlm.nih.gov/pubmed/29959736. http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/348 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/348 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/348 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/348 http://www.fao.org/3/i0936e/i0936e00.htm http://www.fao.org/3/i0936e/i0936e00.htm https://pdfs.semanticscholar.org/2336/6eb20d2f35b137f50927b973b9efba5d5a88.pdf https://pdfs.semanticscholar.org/2336/6eb20d2f35b137f50927b973b9efba5d5a88.pdf https://pdfs.semanticscholar.org/2336/6eb20d2f35b137f50927b973b9efba5d5a88.pdf https://pdfs.semanticscholar.org/2336/6eb20d2f35b137f50927b973b9efba5d5a88.pdf https://pdfs.semanticscholar.org/2336/6eb20d2f35b137f50927b973b9efba5d5a88.pdf https://pdfs.semanticscholar.org/2336/6eb20d2f35b137f50927b973b9efba5d5a88.pdf https://doi.org/10.3390/w2030530. https://doi.org/10.3390/w2030530. https://pubs.acs.org/doi/abs/10.1021/es101403q. https://pubs.acs.org/doi/abs/10.1021/es101403q. https://pubs.acs.org/doi/abs/10.1021/es101403q. https://pubs.acs.org/doi/abs/10.1021/es101403q. https://doi.org/10.1016/j.desal.2009.01.012. https://doi.org/10.1016/j.desal.2009.01.012. https://doi.org/10.1016/j.desal.2009.01.012. https://doi.org/10.1016/j.desal.2009.01.012. https://doi.org/10.1016/j.desal.2009.01.012. https://www.elsevier.com/books/vertical-flow-constructed-wetlands/stefanakis/978-0-12-404612-2 https://www.elsevier.com/books/vertical-flow-constructed-wetlands/stefanakis/978-0-12-404612-2 https://www.elsevier.com/books/vertical-flow-constructed-wetlands/stefanakis/978-0-12-404612-2 https://www.elsevier.com/books/vertical-flow-constructed-wetlands/stefanakis/978-0-12-404612-2 https://www.sciencedirect.com/science/article/abs/pii/s0043135414002103 https://www.sciencedirect.com/science/article/abs/pii/s0043135414002103 https://www.sciencedirect.com/science/article/abs/pii/s0043135414002103 https://www.sciencedirect.com/science/article/abs/pii/s0043135414002103 https://www.sciencedirect.com/science/article/abs/pii/s0043135414002103 https://www.springer.com/gp/book/9783319081762. https://www.springer.com/gp/book/9783319081762. https://www.springer.com/gp/book/9783319081762. https://www.semanticscholar.org/paper/simulation-of-organics-and-nitrogen-removal-from-in-taheriyoun-rad/4613f38db9943d6ef29d71cbafdf08920ba052ab https://www.semanticscholar.org/paper/simulation-of-organics-and-nitrogen-removal-from-in-taheriyoun-rad/4613f38db9943d6ef29d71cbafdf08920ba052ab https://www.semanticscholar.org/paper/simulation-of-organics-and-nitrogen-removal-from-in-taheriyoun-rad/4613f38db9943d6ef29d71cbafdf08920ba052ab https://www.semanticscholar.org/paper/simulation-of-organics-and-nitrogen-removal-from-in-taheriyoun-rad/4613f38db9943d6ef29d71cbafdf08920ba052ab https://www.iasj.net/iasj?func=article&aid=58821 https://www.iasj.net/iasj?func=article&aid=58821 https://www.iasj.net/iasj?func=article&aid=58821 https://www.iasj.net/iasj?func=article&aid=58821 https://doi.org/10.1016/j.desal.2008.03.067 https://doi.org/10.1016/j.desal.2008.03.067 https://doi.org/10.1016/j.desal.2008.03.067 https://doi.org/10.1016/j.desal.2008.03.067 https://doi.org/10.1016/j.desal.2008.03.067 https://www.sciencedirect.com/science/article/abs/pii/s0925857415001196 https://www.sciencedirect.com/science/article/abs/pii/s0925857415001196 https://www.sciencedirect.com/science/article/abs/pii/s0925857415001196 https://www.sciencedirect.com/science/article/abs/pii/s0925857415001196 https://www.sciencedirect.com/science/article/abs/pii/s0925857415001196 https://sswm.info/sites/default/files/reference_attachments/sayadi%20et%20al.%202012%20hybrid%20constructed%20wetlands.pdf https://sswm.info/sites/default/files/reference_attachments/sayadi%20et%20al.%202012%20hybrid%20constructed%20wetlands.pdf https://sswm.info/sites/default/files/reference_attachments/sayadi%20et%20al.%202012%20hybrid%20constructed%20wetlands.pdf https://sswm.info/sites/default/files/reference_attachments/sayadi%20et%20al.%202012%20hybrid%20constructed%20wetlands.pdf https://sswm.info/sites/default/files/reference_attachments/sayadi%20et%20al.%202012%20hybrid%20constructed%20wetlands.pdf http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/206 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/206 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/206 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/206 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/206 %5b1%5d%09https:/www.sciencedirect.com/science/article/abs/pii/s0925857413000566 %5b1%5d%09https:/www.sciencedirect.com/science/article/abs/pii/s0925857413000566 %5b1%5d%09https:/www.sciencedirect.com/science/article/abs/pii/s0925857413000566 %5b1%5d%09https:/www.sciencedirect.com/science/article/abs/pii/s0925857413000566 %5b1%5d%09https:/www.sciencedirect.com/science/article/abs/pii/s0925857413000566 %5b1%5d%09https:/www.sciencedirect.com/science/article/abs/pii/s0925857413000566 https://iasj.net/iasj?func=article&aid=151900 https://iasj.net/iasj?func=article&aid=151900 https://iasj.net/iasj?func=article&aid=151900 https://iasj.net/iasj?func=article&aid=151900 https://iasj.net/iasj?func=article&aid=151900 https://iasj.net/iasj?func=article&aid=151900 https://www.sciencedirect.com/science/article/abs/pii/s0925857408001456 https://www.sciencedirect.com/science/article/abs/pii/s0925857408001456 https://www.sciencedirect.com/science/article/abs/pii/s0925857408001456 https://www.sciencedirect.com/science/article/abs/pii/s0925857408001456 https://www.sciencedirect.com/science/article/abs/pii/s0925857412004193 https://www.sciencedirect.com/science/article/abs/pii/s0925857412004193 https://www.sciencedirect.com/science/article/abs/pii/s0925857412004193 https://www.sciencedirect.com/science/article/abs/pii/s0925857412004193 https://www.mdpi.com/2073-4441/8/4/169 https://www.mdpi.com/2073-4441/8/4/169 https://www.mdpi.com/2073-4441/8/4/169 https://www.mdpi.com/2073-4441/8/4/169 https://www.mdpi.com/2073-4441/8/4/169 https://www.sciencedirect.com/science/article/pii/s135951131000334x https://www.sciencedirect.com/science/article/pii/s135951131000334x https://www.sciencedirect.com/science/article/pii/s135951131000334x https://www.sciencedirect.com/science/article/pii/s135951131000334x https://www.sciencedirect.com/science/article/pii/s135951131000334x m. a. rahi and a. a. h. faisal / iraqi journal of chemical and petroleum engineering 20,2 (2019) 33 40 34 [25] caselles-o ,j g ı , a “i different feeding strategies and plant presence on the performance of shallow horizontal subsurface-flow u ’, s t e , vol. 378, no. 3, p. 253–262., 2007. [26] bialowiec, a., janczukowicz, w., and r , p (20 ) “n wastewater in vertical flow constructed wetlands lwa ” ecological engineering, 37(6), 897-902. [27] raghad f. almilly, mohanned h. hasan(2017) “w w t b l u -solid adsorption using calcined sand-c m u a b ” i journal of chemical and petroleum engineering vol 18 no 2 (2017). [28] h u , e s a v v (20 ) “t olive mill wastewater in pilot-scale vertical flow u ” e e neering, 37(6), 931–939. [29] vohla, c., kõiv, m., bavor, h. j., chazarenc, f., m , ü (20 ) “f phosphorus removal from wastewater in treatment wetlands-a ” e e ( ), 70-89. كفاءة اداء االراضي الرطبة المشيدة التي تعمل بنظام الجريان تحت السطحي لمعالجة مياه لمحطة الرستمية الصرف الصحي المستمر تغذيةوفق نظام ال الخالصة ىذه الدراسة إلى مقارنة أداء ثالث وحدات معالجة تعممبأنظمة الجريانتحت السطحي)العمودي واالفقي تيدف واليجين( المعتمدة في المعالجة الثانوية لمياه الصرف الصحي المتدفقة من األحواض األولية في محطة معالجة م التغذية المستمرة لمياه الصرف بنظا والمراقبةمياه الصرف الصحي في الرستميو في بغداد. كان التشغيم . تم مراقبة لمدة اسبوعين الصحيممدة ستة أسابيعبينما تم اخذ العينات واجراء الفحوصات لممياه الداخمة والخارجة تراكيزكل من األكسجين الكيميائي المطموب والمواد الصمبة الكمية العالقة واألمونيا والنترات والفوسفات مقابل ذغذية والزراعة ومعايير الواليات المتحدة االمريكية لغرض اعادة ااستخدام المياه الناتجة معايير منظمة األ ألذغراض الري.جميع الوحدات كانت مزروعة بنبات القصب المحمي. عند مقارنة اداء االنظمة كان نظام التدفق ين األنظمة المزروعة تحت السطحي اليجين الذي يتألف من وحدةعمودية تمييا وحدة أفقية ىو االفضل من ب لتمكنو من ازالة المموثات المختارة في الدراسة بشكل أكثر كفاءة من األنظمة التي تعمل منفردة. وحقق ىذا و 9.??عند po4-pو nh4-nو tssو codمعدل ازالة لكل مما ياتيالنظام اليجين متوسط الرطبة األخرى. تمت إزالة وحدة التدفق العمودي ٪ عمى التوالي مقارنًة بأنظمة األراضي 9;و :.=>و9.8< ٪ عمى التوالي =..9و 9.9:و 7.7=و 9?عند po4-pو nh4-nو tssو codتحت السطحي و ??في po4-pو nh4-nو tssو codبينما حققت وحدة نظام التدفق تحت السطحي األفقي إزالة لة إزا تريظأدفقفقية الجريان تحت السطحي ابة رطلاضي راألاما ٪ عمى التوالي. أ9..8و ;.:;و 9.:= موديعلا قفدلتا ماظة نطساوتحقيقيا ب ملتي تالة زانة باإلرمقاءالفوسفات لمياه باستثنااملمعال لفضأ سطحي.كان ىناك ارتفاع في تركيز النترات لجميع وحدات المعالجة.لاتتح عوامل مياه الصرف الصحيالصحي، معالجة مياه الصرف سطحي،جريان تحت مشيدة،@ اراضي رطبة الدالة كممات لا https://www.researchgate.net/publication/6395879_impact_of_different_feeding_strategies_and_plant_presence_on_the_performance_of_shallow_horizontal_subsurface-flow_constructed_wetlands https://www.researchgate.net/publication/6395879_impact_of_different_feeding_strategies_and_plant_presence_on_the_performance_of_shallow_horizontal_subsurface-flow_constructed_wetlands https://www.researchgate.net/publication/6395879_impact_of_different_feeding_strategies_and_plant_presence_on_the_performance_of_shallow_horizontal_subsurface-flow_constructed_wetlands https://www.researchgate.net/publication/6395879_impact_of_different_feeding_strategies_and_plant_presence_on_the_performance_of_shallow_horizontal_subsurface-flow_constructed_wetlands https://www.researchgate.net/publication/6395879_impact_of_different_feeding_strategies_and_plant_presence_on_the_performance_of_shallow_horizontal_subsurface-flow_constructed_wetlands https://www.sciencedirect.com/science/article/abs/pii/s0925857411000474 https://www.sciencedirect.com/science/article/abs/pii/s0925857411000474 https://www.sciencedirect.com/science/article/abs/pii/s0925857411000474 https://www.sciencedirect.com/science/article/abs/pii/s0925857411000474 https://www.sciencedirect.com/science/article/abs/pii/s0925857411000474 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/204 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/204 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/204 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/204 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/204 https://www.sciencedirect.com/science/article/abs/pii/s0925857411000528 https://www.sciencedirect.com/science/article/abs/pii/s0925857411000528 https://www.sciencedirect.com/science/article/abs/pii/s0925857411000528 https://www.sciencedirect.com/science/article/abs/pii/s0925857411000528 https://www.sciencedirect.com/science/article/abs/pii/s0925857409002419 https://www.sciencedirect.com/science/article/abs/pii/s0925857409002419 https://www.sciencedirect.com/science/article/abs/pii/s0925857409002419 https://www.sciencedirect.com/science/article/abs/pii/s0925857409002419 https://www.sciencedirect.com/science/article/abs/pii/s0925857409002419 prediction of finite concentration behavior from infinite ijcpe vol.11 no.3 (september 2010) 33 iraqi journal of chemical and petroleum engineering vol.11 no.3 (september 2010) 33 46 issn: 12010-4884 prediction of finite concentrationbehavior from infinite dilution eguilibrium data prof dr. mahmoud o. abdullahil; dr. venus m hameed*; basma m. haddad chemical engineering department – university of nahrin ___________________________________________________________________________________ abstract experimental activity coefficients at infinite dilution are particularly useful for calculating the parameters needed in an expression for the excess gibbs energy. if reliable values of γ∞1 and γ∞2 are available, either from direct experiment or from a correlation, it is possible to predict the composition of the azeotrope and vapor-liquid equilibrium over the entire range of composition. these can be used to evaluate two adjustable constants in any desired expression for g e. in this study mosced model and space model are two different methods were used to calculate γ∞1 and γ∞2 _______________________________________________________________________________________________ introduction activity coefficients at infinite dilution have many uses, some of them: calculating the vapor liquid equilibrium for any mixture, finding the azeotrope composition and pressure; and the estimation of mutual solubility. these calculations are carried out by finding the two adjustable parameters of any desired expression for ge (wilson [1], nrtl [2] and untquac [3] equations. wilson equation has two adjustable constants λ12 and λ21 (energy parameters) where they can be found from the γ∞ by solving the equations for the two component simultaneously. but nrtl or uniquac equations have three parameters. for nrtl equation parameters are τ12, τ21 and α22 where α12 is related to the non randomness in the mixture, the others are considered as energy parameters. the uniquac equation contains three parameters, u12 and u21 adjustable binary energy parameters and the third parameter is considered as coordination number designated as z. all parameters for activity coefficient equations (wilson, nrtl and uniquac) for most binary mixtures are not available in the literature. hence, another method was advocated to calculate these parameters which iraqi journal of chemical and petroleum engineering university of baghdad college of engineering prof dr. mahmoud 0. abdullahil; dr. venus m hameed*; basma m. haddad ijcpe vol.11 no.3 (september 2010) 34 serve to calculate the activity coefficient at infinite dilution γ∞. several methods were developed for the measurement of activities coefficients at infinite dilution (γ∞). the most important methods are: gasliquid chromatography (glc), non-steady-state gas-liquid chromatography, differential ebulliometry, static methods and the dilutor method. the simple experimental method for rapid determination of activity coefficients at infinite dilution is based on gas-liquid chromatography. principal aim of this work is to adopt the activities coefficients at infinite dilution for finding the parameters of different models (i.e., wilson, nrtl, and uniquac) which are not easy to find. the other aim is to evaluate the uses of the activities coefficients at infinite dilution (γ∞) and the methods that can be used and compare between them. mosced model mosced (modified separation of cohesive energy density) is a model proposed by thomas and eckert [4] for predicting limiting activity coefficients from pure component parameters only. it is essential]y an extension of regular solution theory to polar and associating systems. the extension is based on the assumption that forces contributing to the cohesive energy density are additive. those forces included are dispersion, orientation, induction, and hydrogen bonding. the five parameters associated with these forces are the dispersion parameters. a list of the parameters for 15 substances at 20 0c is given in [5]. in a binary mixture, the activity coefficient for component 2 at infinite dilution is calculated from: 12 1 )2121 1 2 21 2 2 2 12 21 2 2 )(()( )(ln d qq rt v                    (1) aaaa v v v v d                   1 2 1 2 12 1ln (2) 4.0 293 293        t t  8.0 293 293 ;        t t  8.0 293 293 ;        t t  (3) ttpol  011.0 (4)       25.1023.0exp4.24.3168.0 toopol   (5) where pol=q4 [1.15 -1.15 exp (-0.020 τ 3 t)] + 1 (6) and where τ = 293/t (t in kelvin). subscript 0 refers to 20°c (293 k), and subscript t refers to system temperature aa = 0.953 — (0.00968)( τ2 2 + α2 β2) (7) where τ, α2 and β are at system temperature t. space model a predictive method for estimating γ ∞ is provided by the solvatochromic correlation of bush and eckert (2000) [6] through the space equation. space stands for solvatochromic parameters for activity coefficient estimation. the space formulation for solvent 1 is:        effeffeff rt v 2121 2 21 2 21 2 2ln    936.0 1 2 936.0 1 2 1ln                   v v v v (8) the dispersion terms are calculated as functions of the molar refractivity index (nd): prof dr. mahmoud 0. abdullahil; dr. venus m hameed*; basma m. haddad ijcpe vol.11 no.3 (september 2010) 35            2 1 2 2 d d n n k (9) where constant k is 15.418 for aliphatic compounds, 15.314 for aromatics, and 17.478 for halogen compounds [6]. r is 1.987,1 is in kelvin, and v is in cm/mol. the polarity and hydrogen-bond parameters for the solvent are ; 1 * 11 1 v ba kt     ; 1 111 1 v dc kt     1 111 1 v fe kt     (10) parameters 2eff , 2eff, and β2eff are for the solute. subscript eff means they are normalized such that limiting activity coefficients for a solute in itself must be unity. calculation of these quantities requires both solvent and solute parameters for the solute.   33.1 * 2 * 1 2222 ktkt oo eff     (11)   20.1 21 2222 ktkt oo eff     (12)   95.0 21 2222 ktkt oo eff     (13) ;; 2 * 22 2 v ba where h     ; 2 222 2 v dc h     2 222 2 v fe h     (14) ; 2 * 21 2 v ba and kt o     ; 2 121 2 v dc kt o     2 121 2 v fe kt o     (15) parameters are given in [6] for 15 components. superscription 0 means that properties for the solute in its solvent like state calculation of activity coefficients at infinite dilution the calculation that carried out by using mosced and space models is shown in table 1 noting that the experimental data are extracted from literatures. the overall average deviation results show that space model equation gives better results than mosced model equation. space is similar to mosced, but reduces the three adjustable parameters of each component to 0 and adds 7 adjustable parameters per functionality of compound. thus, for a database containing 100 different solvents, mosced will have 300 parameters (i.e, equivalent to 3 parameters for each solvent) while, space has about 100 parameters. the main advantage of space over mosced is the prediction of activities coefficients of compounds that were not in the original database provided they have the same functionality as others in the database as well as the required solvent and solute parameters. the space method is probably the best universal available method for estimating activities coefficients at infinite dilution. calculation of the uses of activity coefficient at in finite dilution steps of calculation for azeotropic composition and pressure: a. determining the parameters of the activity prof dr. mahmoud 0. abdullahil; dr. venus m hameed*; basma m. haddad ijcpe vol.11 no.3 (september 2010) 36 coefficient equations (wilson, nrtl, and uniquac) from experimental γ∞. b. calculating of the vapor pressure of pure component at specified temperature using wagner equation ―see appendix a‖. c. at azeotrope the relation volatility (12) is one, hence according to modified rault's law 2 1 1 2    sat sat p p (16) d. substitution of ln( γ1/ γ2 )with the activity coefficient model used. e. solving the composition (x1 and x2) by trial and error. f. calculation of activity coefficient at the azeotropic composition. g. calculation of azeotropic pressure by the following equation sat i az i az pp  (17) table 1 experimental and calculated γ ∞ 1 and γ ∞ 2 by using mosced and space modes system t o c experimental data by mosced model by space model γ ∞ 1 γ ∞ 2 γ ∞ 1 γ ∞ 2 γ ∞ 1 γ ∞ 2 acetone— acetonitrile 45 1.05 1.04 1.105 1.1 0.9954 1.0061 acetone—benzene 45 1.65 1.52 1.48061 1.3809 1.4475 1.5476 acetone —carbon tetrachioride 45 3.00 2.15 2.64655 2.0804 2.5052 2.1490 acetone—methyl acetate 50 1.32 1.18 1.0417 1.0376 1.044 1.0472 acetone —nitro methane 50 0.94 0.96 1.0377 1.0362 1.0499 0.7709 acetonitrile — benzene 100 3.20 3.00 2.3056 2.0093 2.9103 2.3198 acetonitrile — nitro methane 40 0.96 1.00 0.9839 0.9838 0.9173 0.9691 benzene—n-heptane 30 1.35 1.82 1.55136 1.95156 1.3591 1.8565 carbon tetrachioride acetonitrile 60 5.66 9.30 5.2169 7.0278 4.4317 8.816 chloroform—methanol 50 2.00 9.40 3.23174 5.34556 2.1859 7.7311 ethanol—benzene 45 10.6 4.45 13.9057 4.6284 12.9898 5.1616 n-hexane—benzene 69 1.68 1.49 1.73638 1.4944 1.6637 1.3251 n-hexane—methylcyclopentane 69 1.17 1.03 1.01697 1.01402 1.0795 1.0668 met hylcyclopenane—benzene 72 1.47 1.34 1.5328 1.44367 1.2499 1.161 nitroethane—benzene 25 2.78 1.91 2.20598 1.72945 2.2299 1.8874 nitromethane — benzene 25 3.20 3.72 4.00663 3.064 3.5746 3.2465 nitro methane — benzene 45 3.20 3.40 3.42507 2.67778 3.2797 2.9901 2-nitropropane carbon tetrachioride 25 3.24 1.92 4.73716 2.54479 4.7714 2.1122 over all average absolute deviation 0.5794 0.5799 0.4526 0.3042 prof dr. mahmoud 0. abdullahil; dr. venus m hameed*; basma m. haddad ijcpe vol.11 no.3 (september 2010) 37 table 2 calculated and experimental azeotrope composition and pressure using wilson equation of one and two parameters models (γ ∞ 1 and γ ∞ 2) system t o c 12 x1 wt% at azeotrop e exp. x1 wt% at azeotrope cal. with one parameter. x1 wt% at azeotrope exp. cal. with two parameters p az exp. (bar) p az cal. with one parameter. (bar) p az cal. with two parameters (bar) acetone – carbon tetrachloride 45 0.47 91 92.62 83.0338 0.6842 1 0.7045251 0.68578 acetone – chloroform 50 0.3 22.9 23.6269 19.2754 0.6066 2 0.6117064 0.59379 acetonitrile benzene 45 0.47 30.7 30.2309 31.9997 0.3706 4 0.3752523 0.38272 carbontetrachlorid e acetonitrile 45 0.47 84.5 82.1122 84.1988 0.4948 9 0.4544587 0.49205 chloroform methanol 50 0.47 87.8 87.9172 90.8768 0.8359 8 0.7432916 0.83946 methyl cyclopentane benzene 72 0.47 91 84.9816 93.8899 0.6986 1 1.026725 1.01761 nitromethane benzene 25 0.47 6.4 4.44970 6.326 0.1302 6 0.1273378 0.12777 system t o c 12 x1 wt% at azeotrop e exp. x1 wt% at azeotrope cal. with one parameter x1 wt% at azeotrope exp. cal. with two parameters p az exp. (bar) p az cal. with one parameter. (bar) p az cal. with two parameters (bar) nitromethane benzene 45 0.47 9.6 6.89904 9.8254 0.3039 8 0.3011422 0.30282 nitromethane carbontetrachlorid e 45 0.4 10.6 8.44299 9.7866 0.4039 7 0.3863205 0.39316 n-hexane benzene 69 0.47 99.8 87.4161 95.1542 0.7666 0 1.030297 1.02179 %over all average absolute deviation 3.053157 2.4917 0.077836 0.062145 prof dr. mahmoud 0. abdullahil; dr. venus m hameed*; basma m. haddad ijcpe vol.11 no.3 (september 2010) 38 while, when we apply similar calculation procedure but with nrtl equation the following results are obtained table 3. table 3 calculated and experimental azeotrope composition and pressure using nrtl equation of one and two parameters γ ∞ 1 and γ ∞ 2 system t o c 12 x1 wt% at azeo. exp. x1 wt % at azeo. cal. with one parameter x1 wt % at azeo. cal. with two parameters pexp. (bar) p az cal. with one paramete r (bar) p az cal. with two parameters (bar) acetone carbon tetrachloride 45 0.47 91 88.258 7 90.8 107 0.68421 0.70284 0.684 72 acetone chloroform 50 0.3 22.9 26.7476 25.7412 0.60662 0.59908 0.59934 acetonitrile benzene 45 0.47 30.7 17.5476 30.0615 0.37064 0.32809 0.35051 carbonleirachiori de acetonitrile 45 0.47 84.5 80.4428 84.3994 0.49489 0.43264 0.49401 chloroform methanol 50 0.47 87.8 91.365 7 90.3624 0.83598 0.69886 0.86534 methyl cyclopentane benzene 72 0.47 91 91.7786 93.7580 0.69861 1.00296 1.00203 nitromethane benzene 25 0.47 6.4 8.1236 6.7034 0.13026 0.12 795 0.12 773 nitromethane benzene 45 0.47 9.6 12.5 794 9.5541 0.30398 0.30424 0.30265 nitromethane carbontetrachlori de 45 0.4 10.6 13.8429 10.7995 0.4039 7 0.41330 0.40086 n-hexane benzene 69 0.47 99.8 99.9238 99.9208 0.76660 1.01256 1.01257 %over all absolute average deviation 2.4917 0.97596 0.08303 0.061452 when uniqac model is applied the results will change to: table 4 calculated and experimental azeotrope composition and pressure using uniquac equation of one and two parameters γ ∞ 1 and γ ∞ 2 system t o c 12 x1 wt% at azeo. exp. x1 wt % at azeo. cal. with one parameter x1 wt % at azeo. cal. with two parameters pexp. (bar) p az cal. with one parameter (bar) p az cal. with two parameters (bar) acetone carbon tetrachloride 45 0.8 91 90.55 75 90.8730 0.6842] 0.6842 7 0.68408 acetone chloroform 50 3.9 22.9 24.2491 22.9058 0.60662 0.6871 0.59263 acetonitrile benzene 45 0.65 30.7 30.7088 30.7092 0.3 7064 0.15446 0.38309 prof dr. mahmoud 0. abdullahil; dr. venus m hameed*; basma m. haddad ijcpe vol.11 no.3 (september 2010) 39 carbontetrachioride acetonitrile 45 1.4 84.5 84.4917 84.5021 0.49489 0.01852 0.505 12 chloroform methanol 50 0.01 87.8 8 7.8072 89.8536 0.83598 0.88632 0.85041 methyl cyclopentane benzene 72 0.01 91 89.2809 93.8282 0.69861 1.00765 1.00202 nitromethane benzene 25 6 6.4 3.3 7393 6.3678 0.13026 0.12 714 0.13016 nitromethane benzene 45 3.5 9.6 5.28095 9.5828 0.30398 0.30020 0.30789 nitromethane carbontetrachloride 45 2.5 10.6 6.60830 10.7628 0.4039 7 0.3 7879 0.40511 n-hexane benzene 69 0.36 99.8 99.6282 99.8332 0.76660 1.01256 1.01255 %over all absolute average deviation 1.50436 0.52713 0.133212 0.06057 vapor liquid equilibrium calculation the vapor liquid equilibrium (vle) data can be calculated from the activities coefficients at infinite dilution (γ∞1, γ∞2) for any binary system. the equations of vapor liquid equilibrium are calculated using suitable equation of state (eos). peng robinson equation of state [7] is selected to calculate vle since it is the more reliable equation for the calculation. the vle data for 13 systems has been calculated by using wilson, nrtl and uniquac equations for one parameter and two parameters. experimental data from the experimental data can be determined the accuracy of any calculation and this can be done by calculating the deviation between the experimental data and the calculated results. the experimental data for vapor liquid equilibrium obtained from literature for 13 systems are shown in table 5: table 5 vapor liquid equilibrium systems data system p(mmhg) or t in ( o c) no. of data points reference 1 benzene (1) acetonitrile (2) t= 70 21 8 2 methanol (1) water (2) p= 760 26 9 3 acetone(1)-carbon tetrachloride (2) p =450 24 10 4 hexane (1) benzene (2) p=735 11 11 5 acetone (1) benzene (2) p= 738 10 12 6 acetone (1) water (2) p=760 13 13 7 methelcyclopentane (1) benzene (2) p= 760 15 14 8 benzene (1) heptane (2) p= 760 18 15 9 acetone (1) benzene (2) t=45 11 16 10 acetone (1) acetonitrile (2) t=45 10 17 11 acetonitrile (1) nitro methane (2) t=60 10 18 12 nitro methane (1) carbon tetrachloride (2) t==45 12 19 13 carbon tetrachloride (1) acetonitri/e(2) t=45 13 20 steps of calculation of vle data 1. calculating the parameters of the activity coefficient equations (wilson, nrtl and uniquac) from experimental γ∞. 2. for each point of the vle data (x1) the following steps were taken a.finding the pure-component saturated vapor pressure psat1, psat2 at temperature of that point using wagner equation appendix ―a‖. prof dr. mahmoud 0. abdullahil; dr. venus m hameed*; basma m. haddad ijcpe vol.11 no.3 (september 2010) 40 b.calculating the constants of the e~} nation at that temperature corresponding to that point c.calculating the activity coefficients (γ∞1, γ∞2) at that point from the employed equation (wilson, nrtl or uniquac) d.calculating vli from rackett eqtiation which has the form: 2857.0 )1( tr cc sat i zvv   (18) e.solving the following equation where ɸ i sat and ɸi v must be calculated using peng — robinson equation of state.            rt ppv pvxpy sat i l isat i sat iii v ii )( exp (19) f. calculating y1 from the following equation                     rt ppv p px y sat i l i v i sat i sat iii i exp   (20) these steps are repeated for each point of vle data (for each x1) by preparing suitable computer program. steps of investigation for vle calculation the steps of investigation were carried out on 13 different systems some of them are isothermal and the others are isobaric by the three models of wilson, nrtl, and uniquac models and the following results are obtained: table 6 average absolute deviation for vle calculation when wilson, nrtl, and uniquac models are applied for the following systems: system p(mmhg) or t ( o c) no.of data points wilson nrtl uniquac parameters one two parameters one two parameters one two benzene (1) acetonitrile (2) isothermal t=70 21 0.019294 0.019044 0.02 7988 0.017167 0.016661 0.0161 63 methanol (1) water (2) isobaric p=760 26 0.032758 0.02 1413 0.024775 0.020513 0.019821 0.015083 acetone(1) carbon tetrachioride (2) isobaric p=450 24 0.007259 0.003249 0.038627 0.020761 0.003735 0.002005 hexane (1) benzene (2) isobaric p=735 11 0.0233 79 0.00672 7 0.018 786 0.00 7361 0.053490 0.006812 acetone (1) benzene (2) isobaric p=738 10 0.018799 0.008494 0.011519 0.020163 0.008019 0.7854 acetone (1) water (2) isobaric p=760 13 0.012 764 0.010586 0.020921 0.012743 0.011605 0.7809 methelcyclopentane (1) benzene (2) isobaric p=760 15 0.004823 0.003538 0.011235 0.006554 0.003601 0.004110 benzene (1) heptane (2) isobaric p=760 18 0.098944 0.004573 0.014158 0.006411 0.005809 0.004804 acetone (1) benzene (2) isothermal t=45 11 0.004832 0.003964 0.031053 0.007277 0.004547 0.003527 acetone (1) acetonitrile (2) isothermal t=45 10 0.00 7607 0.007518 0.00 7776 0.00 7738 0.007467 0.00 7153 acetonitrile (1) nitro methane (2) isothermal t=60 10 0.025060 0.003938 0.007455 0.005826 0.004469 0.003910 nitromethane (1) carbon tetrachloride (2) isothermal t=45 12 0.009516 0.007698 0.034571 0.006849 0.012256 0.005957 carbon tetrachloride(1) – acetonitrile (2) isothermal t=45 13 0.042118 0.005674 0.018375 0.0183 75 0.019538 0.017218 %over all average absolute deviation 194 0.023627 0.008186 0.022892 0.012134 0.013155 0.007877 prof dr. mahmoud 0. abdullahil; dr. venus m hameed*; basma m. haddad ijcpe vol.11 no.3 (september 2010) 41 also; the results of application of wilson, nrtl, and uniquac relations can be represented on a graph for range of composition for a selected systems which are taken as a sample of calculation for one and two parameters as follows: fig. 2 vle for acetone-carbon tetrachloride at p=450mmhg by using different models of two parameter fig. 1 vle for acetone-carbon tetrachloride at p=450mmhg by using different models of one parameter fig. 4 vle for benzene – acetonitrile at t=70oc by using different models of two parameter fig. 3 vle for benzene – acetonitrile at t=70oc by using different models of one parameter prof dr. mahmoud 0. abdullahil; dr. venus m hameed*; basma m. haddad ijcpe vol.11 no.3 (september 2010) 42 fig. 5 vle for acetone-carbon tetrachloride at p=450mmhg by using wilson models of one and two parameters fig. 6 vle for acetone-carbon tetrachloride at p=450mmhg by using nrtl models of one and two parameters discussion the principle aim in this work is to show if it is possible to use the activities coefficients at infinite dilution to find the parameters of different models. it was suggested two modem methods for calculating the activities coefficients at infinite dilution (γ∞), mosced method (modified separation of cohesive energy density) and space method (solvatochromic parameters for activity coefficient estimation). the two equations are applied to 18 systems and space model gives better results than mosced equation. this work presents the evaluation of the uses of activities coefficients at infinite dilution, γ∞, to calculate the parameters of different equations: wilson, nrtl and uniquac. one of the uses is azeotropic calculation where it is applied for fig. 7 vle for acetone-carbon tetrachloride at p=450mmhg by using uniquac models of one and two parameters prof dr. mahmoud 0. abdullahil; dr. venus m hameed*; basma m. haddad ijcpe vol.11 no.3 (september 2010) 43 10 different binary systems from the experimental γ∞ and the results when compared with the experimental data for azeotrope at the same temperature show as nearly as good if using the actual parameters of the equations. the other use is the calculation of vapor liquid equilibrium data where it applied for 13 different binary systems (194 data points) from the experimental γ ∞ and the results also show as high accuracy as if using the actual parameters of the equations. from these calculations ijniquac model gives the highest accuracy than the other models (wilson, nrtl). in the system that only one γ ∞ is available one parameter equation is used for wilson, nrtl and uniquac equation which it gives result closer accuracy to the two parameters equation. for more details and comparison for all systems which are investigated in this work you can see appendix ―b‖ the results which appeared in the previous tables with their absolute deviations show 1. the most important two methods for calculating the activities coefficients at infinite dilution are space method and mosced method. and it was found that space method is better than mosced where space gives average absolute deviation 0.4526, 0.3042 for γ ∞ 1 and γ ∞ 2 respectively and mosced equation give average absolute deviation equal to 0.5794, 0.5 799 for ‗y‘ respectively. 2. one of the uses of activities coefficients at infinite dilution is the calculation of azeotropic properties (azeotropic composition and pressure). the equations used are wilson, nrtl and uniquac where uniquac equation gives better results than nrtl and wilson equations. 3. the other uses of activities coefficients at infinite dilution is the calculation of vle and the same equation are used (wilson, nrtl and uniquac).uniquac equation also gives the best results than the others. 4. in the system that has only one γ ∞ available, the use of one parameter equation gives result with accuracy near to the two parameters equation which is accepted. conclusions 1. space and mosced are good estimated methods to predict or calculate values of parameters which serve the calculation of activity coefficients at infinite dilution (γ ∞ ). 2. wilson equation of two parameters is the easier method to calculate activity coefficients at infinite dilution (γ ∞ ) since it contain only two parameters. while, nrtl and uniquac models contains three adjustable parameters which make the program which designed to calculate the parameters more difficult. 3. when the obtained parameters applied to calculate activity coefficients at infinite dilution (γ ∞ ) and then calculate vapor liquid equilibrium, azeotropic composition and pressure good agreement with the experimental data are obtained for all applications. 4. when wilson model is applied; the affect of increasing adjustable parameters from one to two parameters will be appeared in azeotropic composition calculation; while it would not had a great affect in the calculation of azeotropic pressure. the same thing is happened when nrtl and uniquac equations are applied for the calculation. 5. the comparison between the wilson, nrtl, uniquac equations for azeotropic composition and pressure calculation; uniquac equation gives best results prof dr. mahmoud 0. abdullahil; dr. venus m hameed*; basma m. haddad ijcpe vol.11 no.3 (september 2010) 44 comparing with the experimental data than nrtl and wilson equation which gives the less accurate results. 6. wilson, nrtl, and uniquac models are applied to calculate vle for thirteen different binary mixtures with 194 data points at different temperatures gives very good accuracies for one parameter and excellent results for two parameters i.e. increasing the number of parameters will increase the accuracy. 7. also, like the calculation of azeotropic composition and pressure the two parameters model gives better results compared with the one parameter models for wilson, nrtl, and uniquac equations with slightly different accuracies. uniquac, nrtl, and wilson models give reasonable accuracy comparing with the experimental data for one and two parameters when vle calculation is adopted. 8. the calculated results show that prediction of vle from activity coefficients at infinite dilution (γ ∞ ) when space and mosced models adopted are excellent. 9. for azeotropic calculation of composition and pressure a very good results are obtained for two parameters models especially for uniquac model. while; reasonable results are obtained for one parameter model. also, uniquac gives more accurate results when compared with wilson and nrtl equations. references 1. g. m. wilson, j. am. chem. soc.: 8~, 127 (1964). 2. .h. renon and j. m. prausintz, aich j.:14,135(1968). 3. j. m smith, h. c. van ness ―introduction to chemical engineering thermodynamics‖ 5 th edition (1996). 4. thomas, b. r., and c. a. eckert: md. eng. chem. process des. dev. 23:194 (1984). 5. bruce b. poling, prausenitz j. m., 0‘connell j. p.: the properties of gases and liquids‖ (1987). 6. bruce b. poling, prausenitz j. m., 0‘connell j. p.: the properties of gases and liquids‖ (2001). 7. d. y. peng and d. b. robinson, md. eng. chem. fundam.: 15, 59 (1976). 8. jean — plerre monfort, j. chem. eng. data, vol. 28, no. 1, 24-27 (1983). 9. per dalager, j. chem. eng. data, vol. 14 no.3, 298-30 1 (1969). 10. bachman k. c., simons e. l.: md. eng. chem. 44, 202 (1952). 11. tonberg g. 0., johnston f.: md. eng. chem. 25, 733 (1933). 12. tailmadge j. a., canuar l. n.: md. eng. chem. 46, 1279 (1954). 13. york r., holmes r. c.: md. eng. chem. 34, 345 (1942). 14. griswold j., ludwig e. e.: md. eng. chem., 35, 117 (1943). 15. brzostowski w.: bull. acad. polon. sci. ser. chim. 8, 291 (1960). 16. brown i., smith f.: austr. j. chem. 10, 423 (1957). 17. brown i., smith f.: austr. j. chem. 13, 30 (1960). 18. brown i., smith f.: austr. j. chem. 8, 62 (1955). 19. brown i., smith f.: austr. j. chem. 8, 501 (1955). 20. brown i., smith f.: austr. j. chem. 7, 264 (1954). appendix “a” wagner equation to calculate pure component vapor pressure prof dr. mahmoud 0. abdullahil; dr. venus m hameed*; basma m. haddad ijcpe vol.11 no.3 (september 2010) 45 equation ―1‖ ln (p/pc) = (1-x) -1 [ax + b x 1.5 + cx 3 + dx 6 ] where x=1-(t/ tc) (a-1) equation ―2‖ lnp=a(b/t) ± cln(t) +dp/t 2 (a-2) component a b c d eq. no. acetone -7.45514 1.2)2 -2.43926 -3.3559 1 acetonii~rile 40.774 5392.43 -4.357 2615 2 benzene -6.98273 1.33213 -2.62863 -3.33399 1 carbon tetrachioride -7.07139 1.71497 -2.8993 -2.49466 1 chloroform -6.95546 1.16225 -2.1397 -3.44421 1 water -7.76451 1.45838 -2.7758 -1.23303 1 methanol -8.54796 0.76982 -3.10850 1.54481 1 methylcyclopentane -7.15937 1.48017 -2.92482 -1.98377 1 n-heptane -7.67468 l.37068 -3.53620 -3.20243 1 n-hexane -7.46765 1.44211 -3.28222 -2.50941 1 nitromethane -8.41688 2.76466 -3.65341 -1.01376 nomenclature p pressure t temperature v volume z compressibility factor x mole fraction in the liquid phase y mole fraction in the gas or vapor phase r gas constant eos equation of state nd refractive index c, d, e, and f equation constants g gibbs free energy r gas constant f fugacity u uniquac parameter x mole fraction in liquid phase y mole fraction in vapor or gas phase latinic symbols γ activity coefficient ɸ fugacity coefficient  nrtl parameter β proportionality factor λ wilson parameter calculated from energy parameter ξ parameter calculated by an equation π parameter in space model subscript 0 system at 1 atmosphere and 20 o c 1 component one in the system 2 component two in the system c critical i component ―i‖ r reduced condition t system temperature superscript ∞ infinite dilution sat saturation ˄ physical property of component in the solution or mixture v vapor phase l liquid phase az azeotropic condition prof dr. mahmoud 0. abdullahil; dr. venus m hameed*; basma m. haddad ijcpe vol.11 no.3 (september 2010) 46 e excess kt solvent state h solute state التنبؤ بتصرف المواد عنذ تراكيز محذدة في التخفيف الالنهائي لمعلوماث التعادل الفيزيائي بسمت موفق حذاد . م.م, فينوس مجيذ حميذ. د.م, محمود عمر عبذ اهلل. د.أ :الخالصت  نحساب انمعامم انضشوسَة نمححىي انطاقة انفائض انحش نگثس " انمخحثشٌ عىذ انحخفُف انالوهائٍ مهم وضشوسٌ جذا e g . ارا كان نذَىا قُم مىثىقة نكم مه  21 , ًسىاء كاوث هزي انقُم محسىتة مه انحجاسب او مه انعالقات جؤدٌ ان انضغط وانىسة نكم مه انسائم و انثخاس كزنك جمكىىا مه حساب كمُات انحىاصن نكم azeotropeامكاوُة اسحىحاج عىذ وقطة انـ هزا َفحح انمجال نحساب . مه انسائم و انثخاس عىذ ظشوف انحشغُم e g. و moscedأخحُش مىدَم كم مه . (wilson, nrtl, uniquac)قذ طثقث فٍ هزا انثحث نحساب ثىاتث كم مه space نحساب كم مه  21 , ijcpe vol.11 no.1 (march 2010) iraqi journal of chemical and petroleum engineering vol.11 no.1 (march 2010) 65-76 issn: 1997-4884 the inhibition effect of peach juice on corrosion of low carbon steel in hydrochloric acid at different temperatures aprael s. yaro * and hadeel f. ibraheem * chemical engineering department college of engineering university of baghdad – iraq abstract the corrosion inhibition of low carbon steel in1n hcl solution in the presence of peach juice at temperature (30,40,50,and 60)°c at concentration ( 5, 10, 20, 30, 40and 50 cm3/l)were studied using weight loss and polarization techniques. results show that the inhibition efficiency was increased with the increase of inhibitor concentration and increased with the increase of temperature up to 50ºc ,above 50ºc (i.e. at 60 ºc) the values of efficiency decreases. activation parameters of the corrosion process such as activation energies, ea, activation enthalpies, ∆h, and activation entropies, ∆s, were calculated. the adsorption of inhibitor follows langmuir isotherm. maximum inhibition efficiency obtained was a bout 91% at 50ºc in the 50 cm3/l inhibitor concentration. the polarization curves show that peach juice is a mixed inhibitor. keywords: low carbon steel, corrosion inhibition, peach juice, electrochemical method introduction corrosion inhibitors are widely used in industry to reduce the corrosion rate of metals and alloys in contact with aggressive environments. most of the corrosion inhibitors are synthetic chemicals, expensive, and very hazardous to environments. therefore, it is desirable to source for environmentally safe inhibitors [1-2]. there are some reports on the inhibition effects of non-toxic compounds on the corrosion of metals. we have recently reported the inhibition effect of amino acids on the steel [1] and aluminum [3] corrosion in acidic media. the inhibition effects of some non-toxic organic compounds have been also reported for steel corrosion [4, 5] but they are expensive. metals and alloy are exposed to the action of acids in industry [6]. processes in which acids play a vary important part are acid pickling, industrial acid cleaning, cleaning of oil refinery equipment, oil well acidizing and acid descaling[6,7]. the exposure can be most sever but in many cases. the aim of this study was to investigate the inhibition effect of peach juice as a cheap, raw and non-toxic corrosion inhibitor on steel corrosion in hydrochloric acid. the electrochemical measurements were used to evaluate the inhibition efficiencies. in addition, the effect of temperature on inhibition behavior of the inhibitor was also studied. experimental work materials and samples peach juice fully ripened peaches were purchased from a local market (baghdad-iraq) the fruits were washed in tap water and then mechanically compressed to obtain corresponding juice. the juice was then filtered to obtain a homogenous solution. in this process 300 ml peach juice from 1kg fresh was obtained. the extracted juice was kept frozen (< 00c) in glass bottles until farther experiment, the concentrations of inhibitor were chosen as5, 10, 20, 30,40and50 cm3/l properties of peach juice: ph = 3.72 , density = 1.078 g/ml university of baghdad college of engineering iraqi journal of chemical and petroleum engineering the inhibition effect of peach juice on corrosion of low carbon steel in hydrochloric acid at different temperatures 66 ijcpe vol.11 no.1 (march 2010) low carbon steel the material of electrodes used was low carbon steel, of chemical composition (wt %) experimental procedure weight loss measurement the experiments were carried out using rectangular steel coupons, each of an area about 10.8 cm2, after polishing and cleaning, accurately weighed to the 4 decimal of gram before it used. specimen was completely immersed in (250 ml) solution of corroding contained in (500 ml) beakers. they were exposed period of 2 hr, according to the test, at desired temperature and inhibitor concentration. after each test, the specimen was washed with running tap water, scrubbed with a brash to remove corrosion products, then washed with tap water followed by distilled water and dried by clean tissue immersed in acctone for 1 minute, dried, immersed in benzene for 1 minute dried and left in a desiccators over silica gel for 1hr. before weighting then accurately to the 4 th decimal and then reweighed. the weight loss was then determined and the rate of corrosion was expressed in (g/m2.hr). electrochemical measurements half-cell measurements the change in potential of the working electrode as carbon steel was recorded as a function of time against saturated calomel electrode (sce) which bridged by a luggin haber probe. the “half cell” potential was carried directly on the display of voltmeter. potentiostatic polarization measurements the data were obtained in three electrode mode. graphite and saturated calomel electrodes were used as counter and reference electrodes respectively, the specimens used as working electrode. corrosion cell parts were joined to each other, and then connected to a power supply, resistors, ammeter, and voltmeter, starting with cathodic polarization until reaching the corrosion potential then continuing with anodic polarization results and discussion weight loss technique corrosion rate (cr) calculations from weight loss data was performed according to the following equation: cr= )(*)( )( 2 hrtimemarea gweightloss (1) the surface coverage ( ) and inhibition efficiency, i% were calculated from the weight loss measurements using the following equations, respectively free inh cr cr )( )( 1 (2) 100 )( )( 1%           free inh cr cr i (3) where (cr)free, (cr)inh, are the corrosion rate (g/m 2 .hr) in the absence and hcl in absence and presence of peach juice as inhibitor of different concentrations at different temperatures. table 1, effect of temperature on the corrosion rate (g/m 2 hr) of carbon steel in 1n hcl acid in absence and presence of peach juice as corrosion inhibiton c si mn cr cu ti v 0.15 0.164 0.58 0.009 0.0468 0.0089 0.0076 ni al co fe mo pb 0.00352 0.0514 0.0091 98.9 0.005 0.05 inhibitor conc. cm 3 /l temperature (°c) 30 40 50 60 nile c.r  i% 5.14 9.53 38.36 61 5 c.r  i% 2.13 0.585 58.5 3.472 0.636 63.6 11.37 0.7 70 23.04 0.621 62.1 10 c.r  i% 2.08 0.594 59.4 2.73 0.7135 71.35 10.43 0.728 72.8 17.07 0.72 72 20 c.r  i% 2.05 0.6 60 2.223 0.766 76.6 9.722 0.75 75 16.47 0.73 73 30 c.r  i% 1.22 0.763 76.3 2.08 0.7814 78.14 6.8 0.8227 82.27 14.14 0.76 76 40 c.r  i% 1.203 0.766 76.6 1.57 0.835 83.5 5.21 0.86 86 12.59 0.81 81 50 c.r  i% 1.147 0.776 77.6 1.3342 0.869 86.9 4.573 0.88 88 10.98 0.82 82 aprael s. yaro and hadeel f. ibraheem ijcpe vol.11 no.1 (march 2010) 67 the corrosion rates of low carbon steel corrosion in absence of inhibitor in 1n hcl acid increased from (5.14 to 61) g/m 2 .h as the temperature increased from 30 to 60 o c .figure 1,shows the variation of corrosion rate with temperature. the corrosion rate in 1n hcl increases sharply with increasing temperature. addition of peach juice as inhibitor reduce corrosion rate generally. table 1, shows the variation in corrosion rate with the inhibitor concentration at various temperature levels. it is clear that the corrosion rate decreases with increasing the concentration of inhibitor at any used temperature, the effect of temperature on corrosion rate for different concentrations of inhibitor is expressed in figure 1, .this figure shows that the corrosion rate increases with increasing temperature at all studied inhibitor concentration. 0 10 20 30 40 50 60 70 20 30 40 50 60 70 temperatuer ( c) c .r (g /m ^ 2 .h r ) nile 5 10 20 30 40 50 fig. 1 effect of temperature on corrosion rate of low carbon steel in 1n hcl at different concentrations of inhibitor. values of inhibition efficiency increase with increasing inhibitor concentration. figure 2, shows the variation of inhibition efficiency with inhibitor concentration. it varies as follows; from 58.5 to 62 % at 5cm 3 /l inhibitor concentration,from 59.4 to 72% at 10 cm 3 /l,from 60 to 73 % at 20 cm 3 /l,from 76.3 to 76% at 30 cm 3 /l ,from 76.6 to 81% at 40 cm 3 /l and from 77.6 to 82% at 50 cm 3 /l as the temperature increased from 30 up to 60 ºc. 0 20 40 60 80 100 0 5 10 15 20 25 30 35 40 45 50 55 60 65 inhibitor concentration(cm^3/l) in h ib it io n e ff ic ie n c y (i % ) 30c 40c 50c 60c fig. 2 variation of inhibition efficiency with inhibitor concentration at different temperature. 50 55 60 65 70 75 80 85 90 25 30 35 40 45 50 55 60 65 70 75 temperature c in h ib it io n e f f ic ie n c y ( i% ) 5 1 2 3 4 5 fig.3 effect of temperature on inhibition efficiency at different inhibitor concentration. figure 3, shows the effect of temperature on inhibition efficiency .inhibition efficiency increase with increasing temperature up to 50ºc then the efficiency reaches a maximum value of 88% at 50 ºc for 50 cm 3 /l . this increase in inhibition efficiency with temperature is presumably due to an increase in adsorption of the inhibitor. above 50 ºc i.e at 60 ºc) the values of efficiency decreases. this may be explained due to the structure degradation of existing organic compounds in the inhibitor[8]. the plot of (i %) vs. inhibitor concentration (cm 3 /l) of peach juice as corrosion inhibitor is found to generally increase with inhibitor concentration and approaches 88% in 1nhcl acid at 50 ºc with 50 cm 3 /l of the inhibitor. while the lowest inhibition efficiency is 58.5% at 30ºc and 5 cm 3 /l inhibitor concentration it is shown in fig 2. the inhibition effect of peach juice on corrosion of low carbon steel in hydrochloric acid at different temperatures 68 ijcpe vol.11 no.1 (march 2010) the corrosion rate data can be used to analyze the adsorption mechanism.the langmuir isotherm was expressed as kc kc   1  (4) where k is the equilibrium constant for the adsorption isotherm representing the degree of adsorption (i.e,the higher the value of k indicates that the inhibitor is strongly adsorbed on the metal surface. c is inhibitor concentration (cm 3 /l) and  is the surface coverage. rearranging equation will give: c k c  1  (5) figure 4, shows plots of c/ vs. c for peach juice as corrosion inhibitor in 1nhcl acid at 30, 40, 50 and 60 ºc. the data fit straight lines indicating that peach juice is adsorbed according to the langmuir adsorption isotherm from the intercept of straight line on the c/ axis; k values are to be calculated as given in table 2. table 4 equilibrium constant for langmuir type adsorption of the inhibitor in 1n hcl acid solution at different temperatures the rectilinear natures of figure 4 indicate an increase in adsorption with an increase in concentration of and that adsorption occurs in accordance with langmuir adsorption equation. it is also noted in fig.4, that the lines accumulated and approximately looked like one line, this is due to the very close range of inhibition efficiency (58.5 – 88%). 0 10 20 30 40 50 60 70 0 10 20 30 40 50 60 inhibitor concentration(cm^3/l) in h ib it o r c o n c e n tr a ti o n /s u r fa c e c o v e r a g e 30 c 40 c 50 c 60 c fig. 4 langmuir adsorption isotherm of peach juice on low carbon steel in 1n hcl at different temperature effect of temperature activation energies of low carbon steel in 1n hcl in presence and absence of peach juice are calculated from arrhenius plots fig 5. it is observed that in uninhibited 1n hcl acid solution,the activation energy of the dissolution process is 16 kcal/mol (67.2 kj/mol). the relationship between the corrosion rate (c.r) of carbon steel in acidic media and temperature (t) is often expressed by: rt ea acr 303.2 loglog  (6) where, ea is the apparent effective activation energy, r the general gas constant and a the arrhenius preexponential factor. a plot of log of corrosion rate obtained by weight loss measurement vs.1/t gave straight lines as shown in figure 4.5. the values of activation energy (ea) obtained from the slop of the lines are given in table 3.the activation energies in presence of inhibitor are lower than uninhibited acid i.e. 16 kcal/mol (67.2 kj/mol) since only small differences are observed between the values of activation energy calculated .at different concentration, the activation energy is considered to be essentially, constant (mean) value of 15.3 kcal/mol (63.58 kj/mol) for peach juice independent of it's concentration.. some authors have reported values of ea < 80 kj/mol as an indicator of physical adsorption, while value of ea > 80 kj/mol are related to chemical adsorption so the lower ea in inhibited solutions compared to the uninhibited indicated of physical adsorption mechanism[9]. 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.95 3 3.05 3.1 3.15 3.2 3.25 3.3 3.35 (1/t)*1000k^-1 l o g (c .r ) 5 10 20 30 40 nil 50 fig. 5 arrhenius plot for log corrosion rates (g/m 2 h) versus reciprocal of absolute temperature at different inhibitor concentration. some other activation parameters such as the enthalpy change of activation (∆h) and entropy change of activation (∆s) were obtained from the eyring transition state equation which is an alternative formula for the arrenius equation[10]: temperature( o c) k value (cm 3 /l) -1 slope 30 0.175 1.14 40 0.306 1.11 50 0.334 1.09 60 0.357 1.1 aprael s. yaro and hadeel f. ibraheem ijcpe vol.11 no.1 (march 2010) 69 )exp()exp( rt h r s nh rt rate   (7) where, h is the plank's constant,(i.e., h = 6.626  10 -34 joule.sec) n the avogadro number,( n = 6.023  10 23 molecules g-mole -1 ) a plot of log ( rate/t) vs. 1/t should give a straight line, figure6,with a slop of (-∆h / 2.303 r)and an intercept of [(log (r/nh) + (∆s/ 2.303 r)],from which the values of ∆s and ∆h were calculated .these are listed in table 3,the values of activation parameter (∆h) in presence of inhibitor are less than that in the absence of inhibitor(nil) . these exhibit high inhibition efficiency at elevated temperature. the positive values of (∆h) both in absence and presence of inhibitor reflect the endothermic nature of the steel dissolution process and means that the dissolution of steel is difficult. it is also clear that the activation enthalpies vary in the same manner as the activation energies, supporting the proposed inhibition mechanism. the values of activation ∆s in the absence and presence of inhibitor are large and negative. this indicates that the activated complex in the rate determining step represents an association rather than a dissociation step, meaning that a decrease in disordering takes place on going from reactants to the activated complex. it is obviously that the ∆s shifts to more negative values (more ordered behavior) with increasing inhibition efficiency, this can be explained that the inhibitor species may involved in the activated complex of the corrosion reaction leading to more ordered system [10]. -3 -2.5 -2 -1.5 -1 -0.5 0 2.95 3 3.05 3.1 3.15 3.2 3.25 3.3 3.35 (1/t)*1000k^-1 l o g (c r /t ) nile 5 10 20 30 40 50 fig. 6, adsorption isotherm plot for log (c.r) of low carbon steel versus reciprocal of absolute temperature in the presence and absence of peach juice table 3, thermodynamic activation parameters for carbon steel in 1n hcl in the absence and presence of inhibitor concentrations polarization technique a total of 28 runs were made,4 runs for uninhibited acid solution and the remaining inhibited acid solution at six levels of inhibitor concentrations and four levels of temperature variation by beta crunch method[12] and the same runs by tafel extrapolation method.the electrode potentials are expressed relative to the saturated calomel electrode (sce). the corrosion potentials obtained from polarization measurements were observed to be influenced by the variables studied. tables 4, results of the corrosion potential of low carbon steel. it can be seen that: 1. the corrosion potential shifts to more positive direction as the inhibitor concentration increases, this shifting explain the anodic nature of inhibitor, which inhibits the anodic reaction more than the cathodic one 2. the values of ecorr also show that the corrosion potential shifts to more negative direction with temperature table 4, corrosion potential, (mv) vs. sce at different temperature and inhibitor concentration inhibitor concentration (cm 3 /l) (∆h) kj/mol (-∆s) j/mol ea kj/mol nil 70.43 125.2 67.2 5 66.56 145.8 64.134 10 61.1 164.33 60.186 20 61.06 165.18 61.61 30 68.98 142.4 66.36 40 65.29 155.6 64.26 50 63.25 163.02 61.32 inh.conc. (cm 3 /l) temperature (º c) 30 40 50 60 nil -480 -496 -505 -513 5 -472 -486 -488 -496 10 -468 -481 -485 -489 20 -463 -475 -481 -487 30 -459 -472 -470 -482 40 -454 -470 -469 -479 50 -450 -465 -466 -476 the inhibition effect of peach juice on corrosion of low carbon steel in hydrochloric acid at different temperatures 70 ijcpe vol.11 no.1 (march 2010) figures 11 through 17 show the polarization curves in absence and presence of the inhibitor at different temperatures. it is clear from these figures that: the increase in temperature shifts the anodic and cathodic curves in the direction of higher current density, table (5 through 8) for beta crunch method and table.9 through 12 for tafel extrapolation method, show that with increasing in temperature in absence and presence of the inhibitor at different concentration. the corrosion rate (corrosion current density) increases, this means that with increasing temperature the efficiency of inhibitor decrease. the same behavior was observed in weight loss technique.figures 7 through 10, show the polarization curves for each temperature 30 ,40 , 50 and 60º c at different inhibitor concentration. it is clear from these figures that the increase in inhibitor concentration shifts the anodic and cathodic curves in the direction of loss current density at all temperature studied, indicate that the peach juice have effect on both anodic and cathodic reaction of corrosion process. computation polarization resistance (rp) the polarization resistance defined as slop of potential current density (∆e/∆i), curve at free corrosion potential (± 20mv) yield the polarization resistance rp[11] it is shown in fig 18 through 21. 0          e p i e r (8) the corresponding corrosion current density depends on kinetic parameters since icorr = f ( , rp) .thus, the simple linear relation that defines the corrosion current density is of the form pr icorr   (9) where  = f (a, c) a , c are taken as positive kinetic parameters for determining icorr of a corroding or oxidizing metallic material.this method requires knowledge of the tafel anodic and cathodic slopes in order to calculate  ) (303.2 . ca ca      (10) the tafel parameters can be determined by mean of experimental measurements carried out over a rang of potential shifting away from the corrosion potential.in the tafel extrapolation methode (± 50 mv) for the corrosion potential,but by the beta crunch method [73] tafel parameters will be calculated with in a bout (± 20 mv) for the corrosion potential. -900 -800 -700 -600 -500 -400 -300 -200 -100 -6.5 -5.5 -4.5 -3.5 -2.5 -1.5 -0.5 log(i)(a/cm^2) e (m v ) nile 5 10 20 30 40 50 fig 7,polarization curves of low carbon steel in 1n hcl and containing different inhibitor concentration at 30 o c -1000 -900 -800 -700 -600 -500 -400 -300 -200 -100 -5.5 -4.5 -3.5 -2.5 -1.5 -0.5 log(i)(a/cm^2) e (m v ) 5 10 nil 20 30 40 50 fig 8 polarization curves of low carbon steel in 1n hcl and containing different inhibitor concentration at 40 o c. aprael s. yaro and hadeel f. ibraheem ijcpe vol.11 no.1 (march 2010) 71 -1000 -900 -800 -700 -600 -500 -400 -300 -200 -100 0 -5.4 -4.4 -3.4 -2.4 -1.4 -0.4 0.6 log(a/cm^2) e (m v ) 30 c 40 c 50 c 60c -1000 -900 -800 -700 -600 -500 -400 -300 -200 -100 -5.5 -4.5 -3.5 -2.5 -1.5 -0.5 log(i)(a/cm^2) e (m v ) nile 5 10 20 30 40 50 fig 9 polarization curves of low carbon steel in 1n hcl and containing different inhibitor concentration at 50 o c. -900 -800 -700 -600 -500 -400 -300 -200 -100 -5.5 -4.5 -3.5 -2.5 -1.5 -0.5 log(i)(a/cm^2) e (m v ) nile 5 10 20 30 40 50 fig 10 polarization curves of low carbon steel in 1n hcl and containing different inhibitor concentration at 60 o c. -900 -800 -700 -600 -500 -400 -300 -200 -100 0 -5 -4 -3 -2 -1 0 1 log(a/cm^2) e (m v ) 30c 40c 50c 60c fig 11, polarization curves of low carbon steel in1n hcl in absence of peach juice at different temperatures. fig 12, polarization curves of low carbon steel in1n hcl with (5cm3/l)) of peach juice at different temperatures. -1000 -900 -800 -700 -600 -500 -400 -300 -200 -100 0 -5.4 -4.4 -3.4 -2.4 -1.4 -0.4 0.6 log(a/cm^2) e (m v ) 30 c 40 c 50 c 60 c fig 13, polarization curves of low carbon steel in1n hcl with (10cm3 /l)of peach juice at different temperatures. -1000 -900 -800 -700 -600 -500 -400 -300 -200 -100 -5.3 -4.3 -3.3 -2.3 -1.3 -0.3 0.7 log(a/cm^2) e (m v ) 30 c 40 c 50 c 60 c fig 14, polarization curves of low carbon steel in1n hcl with (20cm3/l)) of peach juice at different temperatures.. the inhibition effect of peach juice on corrosion of low carbon steel in hydrochloric acid at different temperatures 72 ijcpe vol.11 no.1 (march 2010) -1000 -900 -800 -700 -600 -500 -400 -300 -200 -100 -5.2 -4.2 -3.2 -2.2 -1.2 -0.2 0.8 log(a/cm^2) e (m v ) 30 c 40 c 50 c 60 c fig 15, polarization curves of low carbon steel in1n hcl with (30cm3/l)of peach juice at different temperatures. -900 -800 -700 -600 -500 -400 -300 -200 -100 -5.8 -4.8 -3.8 -2.8 -1.8 -0.8 0.2 log(a/cm^2) e ( m v ) 30 c 40 c 50 c 60 c fig 16, polarization curves of low carbon steel in1n hcl with (40cm3/l)) of peach juice at different temperatures. -1000 -900 -800 -700 -600 -500 -400 -300 -200 -100 0 -5.8 -4.8 -3.8 -2.8 -1.8 -0.8 0.2 log(a/cm^2) e (m v ) 30 c 40 c 50 c 60 c fig 17, polarization curves of low carbon steel in1n hcl with (50cm3/l) of peach juice at different temperatures. -20 -15 -10 -5 0 5 10 15 -0.15 -0.1 -0.05 0 0.05 0.1 0.15 i(ma/cm^2) p o la r iz a ti o n (e -e c o r r )m v fig 18, schematic linear polarization curve of low carbon steel in1n hcl in absence of peach juice at (30ºc). -20 -15 -10 -5 0 5 10 15 20 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 i(ma/cm^2) p o la r iz a ti o n (e -e c o r r )m v fig 19, schematic linear polarization curve of low carbon steel in1n hcl in absence of peach juice at (40ºc) . -30 -20 -10 0 10 20 30 -0.4 -0.2 0 0.2 0.4 i(ma/cm^2) p o l a r i z a t i o n ( e e c o r r ) m v fig.20, schematic linear polarization curve of low carbon steel in1n hcl in absence of peach juice at (50ºc) . aprael s. yaro and hadeel f. ibraheem ijcpe vol.11 no.1 (march 2010) 73 -30 -20 -10 0 10 20 30 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 i(ma/cm^2) p o l a r i z a t i o n ( e e c o r r ) m v fig 21, schematic linear polarization curve of low carbon steel in1n hcl in absence of peach juice at (60ºc) . table 5, data of beta crunch for polarization measurements of low carbon steel in 1n hcl in absence and presence of different concentration of peach juice at t= (30º c) inh. conc.(cm 3 /l) rp (ω.cm 2 ) a (mv/dec) c (mv/dec) icorr (a/cm 2 ) eff (i%) nil 153.5 33.244 -56.46 5.9*10 -5 5 338.1 32.54 -55.8 2.64*10 -5 54 10 395.8 36.65 -54.3 2.4*10 -5 60 20 493.8 39.3 -54 2*10 -5 68 30 608.9 37.135 -56.7 1.6*10 -5 74 40 683.6 35.2 -51.8 1.33*10 -5 77 50 750.5 33.7 -55.2 1.21*10 -5 78 table 6, data of beta crunch for polarization measurements of low carbon steel in 1n hcl in absence and presence of different concentration of peach juice at t= (40º c) inh. conc.(cm 3 /l) rp (ω.cm 2 ) a (mv/dec) c (mv/dec) icorr (a/cm 2 ) eff (i%) nil 115.16 35.67 -57.66 8.3*10 -5 5 293.4 40.69 -63.49 3.6*10 -5 60 10 382.2 42.8 -55.227 2.7*10 -5 70 20 435.3 38.529 -58.63 2.3*10 -5 73 30 576.5 40.93 -59.74 1.8*10 -5 79 40 664.3 38.89 -55.39 1.49*10 -5 82 50 665 33.225 -48.36 1.288*10 -5 83 the inhibition effect of peach juice on corrosion of low carbon steel in hydrochloric acid at different temperatures 74 ijcpe vol.11 no.1 (march 2010) table 7, data of beta crunch for polarization measurements of low carbon steel in 1n hcl in absence and presence of different concentration of peach juice at t= (50º c) inh. conc.(cm 3 /l) rp (ω.cm 2 ) a (mv/dec) c (mv/dec) icorr (a/cm 2 ) eff (i%) nil 92.3 44.278 -76.42 1.32*10 -4 5 264 38.363 -61.478 3.8*10 -5 65 10 316.3 41.351 -64.968 3.46*10 -5 71 20 425.25 45.34 -60.133 2.6*10 -5 78 30 507.8 44.27 -63.361 2.2*10 -5 82 40 568 40.497 -59.84 1.8*10 -5 84 50 695 35.93 -54.35 1.35*10 -5 88 table 8, data of beta crunch for polarization measurements of low carbon steel in 1n hcl in absence and presence of different concentration of peach juice at t= (60º c) inh. conc.(cm 3 /l) rp (ω.cm 2 ) a (mv/dec) c (mv/dec) icorr (a/cm 2 ) eff (i%) nil 73.2 51.35 -68.23 1.73*10 -4 5 146.4 47.76 -72.81 8.68*10 -5 50 10 161.35 46.57 -70.08 7.5*10 -5 55 20 183.5 47.56 -72.42 6.8*10 -5 60 30 198.1 44.133 -69.63 5.9*10 -5 64 40 224.7 49.166 -72.3 5.17*10 -5 68 50 265.7 47.42 -68.588 4.6*10 -5 73 table 9, data of tafel extrapolation for polarization measurements of low carbon steel in 1n hcl in absence and presence of different concentration of peach juice at t= (30º c). inh. conc.(cm 3 /l) rp (ω.cm 2 ) a (mv/dec) c (mv/dec) icorr (a/cm 2 ) eff (i%) nil 153.5 80.64 -103.98 1.3*10 -4 5 338.1 56.87 -124.16 5.11*10 -5 60.6 10 395.8 62.3 -127.195 4.74*10 -5 63.5 20 493.8 57.93 -125.044 3.52*10 -5 72.9 30 608.9 57.48 -89.27 2.52*10 -5 80.6 40 683.6 63.09 -108.02 2.5*10 -5 80.7 50 750.5 64.174 -133.68 2.49*10 -5 80.9 table 10, data of tafel extrapolation for polarization measurements of low carbon steel in 1n hcl in absence and presence of different concentration of peach juice at t= (40º c). inh. conc.(cm 3 /l) rp (ω.cm 2 ) a (mv/dec) c (mv/dec) icorr (a/cm 2 ) eff (i%) nil 115.16 105.38 -109.59 1.93*10 -4 5 293.4 134.9 -166.83 1.13*10 -4 40 10 382.2 64.64 -128.7 5.09*10 -5 73 20 435.3 58.94 -156.02 4.31*10 -5 77 30 576.5 55.121 -131.9 2.9*10 -5 84 40 664.3 116.12 -94.43 3.4*10 -5 82 50 665 61.81 -114.98 2.63*10 -5 86 aprael s. yaro and hadeel f. ibraheem ijcpe vol.11 no.1 (march 2010) 75 table 11, data of tafel extrapolation for polarization measurements of low carbon steel in 1n hcl in absence and presence of different concentration of peach juice at t= (50º c). inh. conc.(cm 3 /l) rp (ω.cm 2 ) a (mv/dec) c (mv/dec) icorr (a/cm 2 ) eff (i%) nil 92.3 87.97 -126.5 2.62*10 -4 5 264 60.85 -132.88 6.78*10 -5 74 10 316.3 77.433 -120.45 6.69*10 -5 74 20 425.25 98.5 -109.87 5.24*10 -5 80 30 507.8 61.59 -116.9 3.52*10 -5 86 40 568 77.93 -91.6 3.33*10 -5 87 50 695 49.44 -113.4 2.2*10 -5 91 table 4.12, data of tafel extrapolation for polarization measurements of low carbon steel in 1n hcl in absence and presence of different concentration of peach juice at t= (60º c). inh. conc.(cm 3 /l) rp (ω.cm 2 ) a (mv/dec) c (mv/dec) icorr (a/cm 2 ) eff (i%) nil 73.2 79.47 -138.24 3.22*10 -4 5 146.4 79.23 -87.7 1.29*10 -4 60 10 161.35 48.9 -123 9.5*10 -5 70 20 183.5 73.25 -125.01 1.04*10 -4 67 30 198.1 70.53 -118.13 9.33*10 -5 71 40 224.7 57.19 -158.24 8.3*10 -5 74 50 265.7 56.7 -131.3 6.76*10 -5 79 conclusions 1. it was found that the activation energy in absence of inhibitor was 16 kcal/mol (67.2 kj/mol) .this value decreased down to a constant mean 15.3 kcal/mol. this mean that the activation energy of the reaction is inhibitor concentration independent. 2. inhibition efficiency increase with increasing temperature to 50ºc and then decreasing with temperature while this efficiency increased with increas inhibitor concentration. 3. the positive value of ∆h both in absence and presence of inhibitor reflect the endothermic nature of the steel dissolution process. the values of ∆s are large and negative meaning that decrease in disordering takes place on going from reactants to the activated complex. 4. it was found that the corrosion current density increase with increasing temperature and decrease with increasing inhibitor concentration. 5. the resistance polarization decrease with increasing temperature and increase with increasing inhibitor concentration. 6. this investigation shows that peach juice is an effective friendly inhibitor, max. efficiency obtained was a bout 91%. 7. peach juice was found to effect both anodic and cathodic reaction as mixed effect inhibitor, but more is anodic inhibitor. references 1. h.ashassi-sorkhabi,m.r.majidi and k.seyyedi, applied surface science,225(2004)176. 2. a.y. el-etre, corrosion science,40 (1998)1845. 3. h. ashassi-sorkhabi, z. ghasemi and d. seifzadeh, applied surface science,249 (2005)408. 4. k. c. emregül and m. hayvalı, materials chemistry and physics,83(2004)209. 5. s.a. abd el-maksoud, electrochimica acta,49(2004) 4205. the inhibition effect of peach juice on corrosion of low carbon steel in hydrochloric acid at different temperatures 76 ijcpe vol.11 no.1 (march 2010) 6. g.i gardner. corrosion inhibitor, c.c. nathan ed., nace, 156. 7. s.s. abd el rehim, m.a.m. ibrahim and k.f. khalid. the inhibition of 4-(2'-amino-5'methylphenylazo) antipyrine on corrosion of mild steel in hcl solution. material chemistry and physics,70(2001)268. 8. ashassi-sorkhabi h.,d.seifzadeh "the inhibition of steel corrosion in hydrochloric acid solution " international journal of electrochemical science may(2006)(www. electrochemsci.org). 9. olivares.o,likhanova n.v,"electrochemical and xps studies of decylamides of α-amino acids adsorption on carbon steel in acidic environment" journal of applied surface science 252(2006) 28942909 www.elsevier.com/locate/apsusc. 10. khan.s.,quraishim a. "inhibition of mild steel corrosion in sulfuric acid solution by thiadiazoles" journal of applied electrochemistry 36,539-544. (2006). 11. george, g., “corrosion inhibitors”; (nace), houston texas (1974). 12. n.green, &r.gandi, material performance, july, (1982). 13. s.d. casini and r. bagger-jorgensen, cross flow filtration of fruit juice, (www.mst.dk/udgiv/publications/2000/87-7944-1343/html/kap02_eng.htm). 14. e.s. ferreira, c. giacomelli, f.c. giacomelli, a. spinelli; materials chemistry and physics,83(2004)129. 15. e. rocca, c. rapin and f. mirambet, corrosion science,46(2004)653 16. k. tebbji, h. oudda, b. hammouti, m. benkaddour, m. el kodadi and a. ramdani, colloids and surfaces a: physicochem. eng. aspects259(2005)143 http://www.elsevier.com/ http://www.mst.dk/udgiv/publications/2000/87-7944-134-3/html/kap02_eng.htm http://www.mst.dk/udgiv/publications/2000/87-7944-134-3/html/kap02_eng.htm iraqi journal of chemical and petroleum engineering vol.16 no.3 (september 2015) 4552 issn: 1997-4884 kick tolerance control during well drilling in southern iraqi deep wells nagham jasim al-a'ameri university of baghdad, college of engineering, petroleum department abstract the importance of kick tolerance in well operations has recently increased due to its implications in well design, in drilling and well control. to study a simple method for the application of kick tolerance concept in an effective way on the basis of field data, this research purpose is to improve knowledge about kick tolerance and represents a technical basis for the discussion on revision of standard procedure. the objective of this work is to review and to present a methodology of determination the kick tolerance parameters using the circulation kicks tolerance concepts. the proposed method allows to know, to evaluate and to analyze the kick tolerance problem in order to make the drilling execution safer and more economical by reducing the probability to have an incident. the calculations of presented methodologies were based upon calculated input values such as ppore and pfrac. and not upon measured leak-off test and rft (less accurate) input values as in traditional methods. the paper also analyses the calculations not with kt parameters only, but it has continued to give the killing operation procedure to such high pressure high temperature (hpht) wells. key words: gas kick, killing operation, kick tolerance, drilling control, casing setting depth. introduction kick tolerance (kt) is commonly defined as the maximum volume of a given type of influx (typically gas), we mainly discuss gas kicks because gas is much more difficult kick fluid to handle than liquid. a small volume of gas at the bottom of a well is potentially dangerous because it expands when approaching the lower pressure near the surface. at low pressure it will expand and displace a corresponding amount of mud from the well, thus, reducing the bottom hole pressure which in turn allows more gas to flow into the well from the pores[7]. another problem with gas kicks is that gas decreases mud rheology, especially in oil base mud, and barite falls out. barite must, by the way, be delivered from the supply base in adequate amount to increase the mud weight of the total active mud volume. many companies believe that kt calculations help to quantify safety margins that exist between expected wellbore conditions and incrementally higher well design limits. however, iraqi journal of chemical and petroleum engineering university of baghdad college of engineering kick tolerance control during well drilling in southern iraqi deep wells 46 ijcpe vol.16 no.3 (sept. 2015) -available online at: www.iasj.net one big issue in the industry today is the lack of consistency about kt calculation, leading to significant confusion and increased risk [1]. there are two situations in dealing with gas kick, in the case of the open well, when the gas reaches the surface as it is circulated out of the hole its volume expansion can be calculated using ideal gas law (boyle’s law): = when gas is injected (from the formation) in to the closed well it will travel up the well with its pressure unchanged. in such well if gas expansion is prevented then hole will fracture when gas reaches the surface. hence when a kick is taken in a well, gas expansion must be allowed to take place to reduce well pore pressure. kick tolerance is based on the fact that during a gas kick, gas is circulated out of the well at a controlled rate to reduce its pressure and to keep its expanded volume at surface to a manageable amount. what is kick tolerance many definitions had been given to explain kt, for practical purposes, kick tolerance may be defined as the maximum kick size which can be tolerated without fracturing the previous casing shoe. kick tolerance may also be defined in the term of the maximum allowable pore pressure at next total depth or maximum allowable mud weight which can be tolerated without fracturing the previous casing shoe[2], [6]. kick tolerance therefore depends on the maximum kick size, maximum formation pressure at the next total depth (td) and the maximum mud weight which can be tolerated without fracturing the previous casing shoe (the weakest point in the open hole). other factors which affect on kick tolerance include density of the invading fluid and the circulating temperature. how to calculate kick tolerance kick tolerance should be calculated prior to drilling ahead at intervals through the hole section to be drilled at the expected mud. if a factor such as mud weight or drill string geometry is changed, then the kick tolerance must be recalculated. to determine the magnitude of kick tolerance, the parameters such as (pore pressure at td, maximum mud weight to be used and fracture gradient at current casing shoe) are necessary to design influx volume that can be safely circulated out. kick tolerance should be calculated in terms of [1]:  kick volume which can be circulated out without fracturing the previous casing shoe.  additional mud weight over current mud weight.  drilling kick tolerance which is the maximum pore pressure which can be tolerated without need to exceed the maximum allowable mud weight. the amount of influx volume that entering in well depends on:  underbalanced between mud weight and pore pressure  reservoir porosity and permeability  influx type  sensibility and reliability of detection equipment  reaction time of well control crew  type well shut in procedure after closing the well, the pump seals the well at the drill string end, and at the other end by means of closed bop (blowout pressure) and surface choke. inside the drill string, the liquid composition is assumed to be uncontaminated, so that the new formation pressure [1], [5] becomes: nagham jasim al-a'ameri -available online at: www.iasj.net ijcpe vol.16 no.3 (sept. 2015) 47 ppore = psidp +ρmud .g.hwell = ρkill .g.hwell … (1) where: ppore: formation pore pressure at the next hole depth td, psi. psidp : shut in pressure in drill pipe, psi. hwell : true vertical depth of the well, ft. ρmud : mud density in use at next hole, ppg. ρkill : density of mud required to killing the well if necessary, ppg. then: psidp = pfrac. ρmud .g.hwell ... (2) pfrac.: fracture pressure at the next hole depth td, psi. and the maximum allowable annular surface pressure (maasp) is: maasp= (ρfrac.ρ2 ) .g.hcsg.shoe ... (3) where: ρfrac. : mud weight equivalent to fracture pressure in casing shoe, ppg. ρ2 : mud weight in annulus before shut in, ppg. hcsg : well depth at casing shoe, ft. where: ρfrac. = ... (4) if the surface pressure rises above maasp, the formation below the casing shoe will fracture, and hence the required mud weight to balance the pore pressure: = + … (5) when the gas reaches the shoe while being circulating, the pressure at the casing shoe is given by fracture gradient at shoe, and then the height of gas at casing shoe is: hsheo= ... (6) where: fg : fracture gradient in casing shoe, psi/ft. g: gradient of gas (0.05-0.15). the volume of gas influx at casing shoe is: v1= hsheo * ca .... (7) where: ca: capacity between pipe & hole (ca= . dh: next hole diameter, in. dp: drill pipe diameter, in. at bottom hole conditions the volume influx (v2) is given by: = v2= ... (8) where: p1: fracture pressure at shoe, psi. p2: formation pressure at the next hole, psi. t1: temperature at shoe, f 0 . t2: temperature at total depth, f 0 . the volume v2 is the circulation kick tolerance. kt= (fg – ρmud) ... (9) the volume at the kick zone, which will cause the pressure at the shoe to reach the maximum allowable value when the kick reaches the shoe, it is important to note that some sources stop calculations at this point and consider this the final value for kick tolerance. the allowable value when the kick enters the wellbore might be higher due to inclination or smaller due to the decrease in the annular capacity. kick tolerance control during well drilling in southern iraqi deep wells 48 ijcpe vol.16 no.3 (sept. 2015) -available online at: www.iasj.net and from these the height of the kick at the kick zone isv2. hkick zone= ... (10) where: fg : fracture gradient at total depth, psi/ft. then the volume of gas influx at kick zone is: v3= hkick zone * ca ... (11) where: ca: capacity of kick zone between drill collar & hole (ca= . dh: td hole diameter, in. dc: drill collar diameter, in. then if (v3 ≥ v2) the kick tolerance = v2 else kick tolerance = v3 the volumes are compared and the assumption is that the smaller value will create a more conservative, hence safer, kick tolerance. it is conceptually wrong to neglect the bha (bottom hole assembly) length (4) . if the kick will most likely not be circulated out of the wellbore, or it will create an unsafe and very hard task for the drilling crew, as it will reach the top of the drill collars with a kick height greater than hshoe , which in consequence would induce losses at the shoe. when bha ≥ hshoe some other calculations have to be performed in order to have a more accurate value for kick tolerance, where the calculations must be done for the volume across the top of drill collars. v3 must be taken to the bottom of the wellbore using boyle’s law, so v3 will calculate using equation (8). in the above procedure, reality of the change in temperature will have effect in the mud rheology and gas density and hence on kick tolerance parameters have taken in calculation (equation 8). kick tolerance calculation in southern iraqi deep wells in this research two abnormal deep wells data (with total depth reaches to 15000 ft and temperature reaches to 300f 0 ) are used to study kt. when drilling into area of overpressure with rapid pore pressure increase, and increasing mud weight to compensate, the kt (limited by formation strength at the previous casing shoe) calculations are made using predicted formation pore pressure, mud density and fracture pressure gradient which were calculating in a previous research (3) , while methods introduced in literatures was define on the basis of shut in well pressure(measured pressure in shut in well, commonly called leak-off-test(lot)). for two abnormal deep wells in southern iraq with three casing shoedepths for each well, the input data for the studied wells have illustrated in table (1), kt is calculating in terms of maximum kick size (the smallest volume between v2 and v3, calculated using eq.8 or eq.11) at td, shut in drill pipe pressure psidp (calculated using eq.2), maasp (calculated using eq.3), to be compared with surface pressure in order to know if the formation below casing shoe will fracture or not. and the density of mud required to killing the well if necessary (ρkill, calculated using eq.5) or in term of additional mud weight required to kill the well. all the above parameters are calculated and listed below in tables (2) and table (3) consequently for the two studied wells. nagham jasim al-a'ameri -available online at: www.iasj.net ijcpe vol.16 no.3 (sept. 2015) 49 results to avoid kick we must keep the bottom hole pressure greater than formation pore pressure, to do this and for planning purposes, it is useful to construct a kick tolerance graph for each well as shown in figure (1) and figure (2). in that figures, the kick volume is plotted on x-axis (point 2), and the sidpp is plotted on y-axis. (point 1) is the maximum sidpp that was calculated using equation (2). (point 2) is the maximum kick volume as obtained by equation (8) for zero initial drill pipe shut in pressure. the straight line joining points 1 and 2 is called the kick tolerance graph. all points to the top and right of the line represent internal blow out and lost circulation conditions (due to formation fracturing). points below the line represent safe conditions and give kick tolerance for any combination of kick size and drill pipe shut in pressure (sidp). fig. 1, kick tolerance graph for the well a table (4) and table (5) listed the expected sidpp for each calculated kick volume. for the studied well, well control could be lost due to:  high pressure zone not detected.  mud density too low due to gas cut.  lost circulation due to pwell > pfracture.  not keeping annulus fill with mud during tripping. fig. 2, kick tolerance graph for the well b for any calculated kick size use figure 1 and 2 to predict the drill pipe shut in pressure psidp. figure 3 to figure 4 shows the effect of the initial kick volume at the casing shoe setting depth using the proposed method. these results were obtained using the parameter bha length (difference between tvd and casing shoe depth) shown in table.1 and kick volume in table 2 and 3. it is important to emphasize that the casing setting depth analysis was performed from the bottom of the well to the surface (from bottom to top). having this in mind, it can be observed in fig. 3 that an increasing kick volume requires the casing to be set closer to the final depth of the well. this point can be explained by the fact that the casing shoe position need to find higher fracture pressures (this is achieved by going deeper and closer to the final depth) to tolerate increasing kick volumes. 0 500 1000 1500 2000 2500 0 100 200 300 400 s id p , p si kick volume, bbl hole depth=11578.08 hole depth=5928.478 hole depth=14714.57 . 0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 0 500 1000 1500 s id p , p si kick volume, bbl hole depth=12559.06 ft hole depth=7168.635 ft hole depth=14845.8 ft kick tolerance control during well drilling in southern iraqi deep wells 50 ijcpe vol.16 no.3 (sept. 2015) -available online at: www.iasj.net fig. 3, kick volume and open hole lengths for the well a fig. 4, kick volume and kick height hkick for the well a concluded killing procedures for the studied wells there exist a number of different killing methods (1) , the two main methods are the driller’s and the engineer’s method. the engineer’s method is also called the wait & weight method (w&w). the most common method of restoring an overbalanced situation after a kick has occurred is the driller’s method. once a kick has been detected, and the well has been closed, it is time to start planning the killing of the well. first deciding what circulation rate should be used to kill the well (ρkill, shown in table 2 and 3 as an additional mud weight). in the driller’s method the pore fluid is displaced before kill mud is injected. this simplifies the operation but also induces higher pressure in the incased annulus, and the choke nozzles erode quicker. this could also lead to fracturing the casing shoe. if the surface pressure rises above the maximum allowable annular surface pressure, maasp (shown in table 1 and 2), then the formation below the casing shoe will be fracture. table 1, input data in kick tolerance calculations 0 10 20 30 40 50 60 0 100 200 300 400 bha, ft kick volume, bbl 2000 2200 2400 2600 2800 3000 3200 3400 3600 3800 4000 0 100 200 300 400 kick volume, bbl ki ck h ig h ts , ft well depth(td), f casing shoe depth, ft fracture gradient at shoe, ppg mud weight, ppg hole diameter, in drill pipe diameter, in drill coller diameter , in bha length, ft well a 5928.478 5915.35 4 13.46154 10.9956 12.25 5 6.75 13.124 11578.08 11538.7 1 14.80769 10.9956 8.375 5 6.75 39.37 11530.08 12992.1 3 16.53846 14.4230 8 5.875 3.5 4.75 48 well b 7168.635 7125.98 4 13.46154 9.7461 17.5 5 8 42.7 12559.06 12486.8 8 17.69231 10.6624 12.25 5 8 171.2 14845.8 14839.2 4 19.03846 15.5771 8.5 5 6.75 6.6 nagham jasim al-a'ameri -available online at: www.iasj.net ijcpe vol.16 no.3 (sept. 2015) 51 table 2, calculated parameters of kick tolerance for the well a table 3, calculated parameters of kick tolerance for the well b well. b estimad kick tolerae tvd, ft mud weight, ppg pore pressure, ppg kick volume, bbl add. mud weight, ppg maasp, psi 7168.63 5 9.7461 9.615385 968.4887 3.715438 1425.197 12559.0 6 10.6624 13.26923 610.8042 7.029908 2996.85 14845.8 15.5771 16.92308 64.93105 3.461362 1929.101 table 4, calculated sidpp for each expected kick volume for the well a well. a estimatd kick tolerance tvd, ft mud weight, ppg pore pressure, ppg kick volume, bbl add. mud weight, ppg maasp, psi 5928.478 10.9956 9.615385 289.7607 2.465938 1183.071 11578.08 10.9956 12.26 88.62963 3.812092 3115.453 14714.57 14.42308 15.96154 9.915399 2.115385 2468.504 kick volume, bbl well. a sidpp, psi 100 td=5028.475 ft 1020.20 200 1281.90 300 1543.60 400 1805.30 450 1936.15 50 td=11578.08 ft 3577.30 100 4867.30 150 6157.30 3 d=14714.57 ft 1861.30 10 2870.00 kick tolerance control during well drilling in southern iraqi deep wells 52 ijcpe vol.16 no.3 (sept. 2015) -available online at: www.iasj.net table 5, calculated sidpp for each expected kick volume for the well b fig. 5, kick volume (at the first total depth and the first casing depth) for the well a references 1pal skalle and ventuse "pressure control during oil well drilling", isbn 978-87-7681-941-5, 2011. 2hussain, rabia: “well engineering and construction”, entrac consulting 2002, isbn: 0954108701. 3s.n., al-mussawi , s.m. hamedallah and n. j. al-a'amery "prediction of fracture pressure gradient for deep wells in southern iraqi oil fields", the 6 th engineering conference april 2009, collage of engineeringuniversity of baghdad,p. (97-113)". 4h. santos, e. catak and s. valluri, safekick, spe: “kick tolerance misconceptions and consequences to well design”, paper, spe/iadc 140113, presented at the 2011 drilling conference and exhibition in amsterdam, the netherlands, 13 may, 2011. 5gabriele zaccaria "kick tolerance" master in petroleum engineering san donato milanese – october the 23rd-24th 2008, eni corporate university. 6carolina silva avelar and paulo roberto ribeiro "the study of well plaining using the kick tolerance concept "18th international congress of mechanical engineering abcm november 611, 2005. 7helio santos and paul sonnemann, "transitional kick tolerance", society of petroleum engineers, spe 159175, 2012. kick volume, bbl well. a sidpp, psi 50 td=7168.6 ft 4726.50 100 6783.00 150 8839.50 200 10896.0 20 td=12560 ft 4713.46 40 4862.92 60 5012.38 80 5161.84 100 5311.30 120 5460.76 20 d=14846 ft 2698.42 40 2726.84 60 2755.26 iraqi journal of chemical and petroleum engineering vol.15 no.4 (december 2014) 15-24 issn: 1997-4884 electrofacies characterization of an iraqi carbonate reservoir dahlia abdulhadi abdulateef , ahmed zarzor and *dr. mohammed s. al jawad, university of baghdad, petroleum engineering department and, * university of technology, petroleum technology department abstract predicting peterophysical parameters and doing accurate geological modeling which are an active research area in petroleum industry cannot be done accurately unless the reservoir formations are classified into sub-groups. also, getting core samples from all wells and characterize them by geologists are very expensive way; therefore, we used the electro-facies characterization which is a simple and cost-effective approach to classify one of iraqi heterogeneous carbonate reservoirs using commonly available well logs. the main goal of this work is to identify the optimum e-facies units based on principal components analysis (pca) and model based cluster analysis(mca) depending on available well logs data for four wells from an iraqi carbonate oil field. the optimum e-facies units came from comparing them with geologist classification units for these four wells. also, we conclude that the value of permeability is not important to get the optimum e-facies units. several runs have been tried each with different number of units using the electro-facies approach. the results of the techniques show very good match of the tops for various units with the actual ones. this application also shows the power and versatility of electrofacies characterization in improving reservoir descriptions in complex carbonate reservoirs. keywords: electrofacies, permeability prediction, zonation methods introduction electrofacies determination method is based on attempts to identify clusters of well log responses with similar characteristics which used to perform the electrofacies classification. efacies is a window based software for electrofacies characterization based on the multivariate analysis from well logs. generally a suite of well logs can provide valuable but indirect information about mineralogy, texture, sedimentary structure, fluid content and hydraulic properties of a reservoir. the distinct log responses in the formation represent electrofacies that very often can be correlated with actual lithofacies identified from cores, based on depositional and diagenetic characteristics. the importance of electrofacies characterization in reservoir description and management has been widely recognized. in this software, the calculation parts are done by fortran 77 and the graphical interface parts are done by the program c++.this classification of electrofacies in our study is done by efacies iraqi journal of chemical and petroleum engineering university of baghdad college of engineering electrofacies characterization of an iraqi carbonate reservoir 16 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net software which developed by dr. a. datta-gupta from texas a&m university [1, 2, and 3]. data preparation the well log data considered in this analysis has been gathered from 4 wells (well a, well b, well c and well d). logs of 230 sample data from 4 well were used in this field with thier corresponding depth for characterizing the electrofacies groups. the well logs used are : resistivity (lld) and (sfl), neutron porosity (nphi), density (rhob) and sonic log (dt). these logs are considered as independent variables. the number of independent variables has been reduced to obtain the optimum results. principal component analysis (pca): principal component analysis (pca) technique is a mathematical tool used for summarizing the data without losing too much information. it reduces the dimensionality of the problem by introducing principal components. principal components are identified within the defined variable space. they provide an alternate coordinate system in multidimensional space for displaying data without too much lose of information. principal components are constructed through linear combination of variables [1 and 4]. the eigenvectors and covariance matrix provide the coefficients for principal component transformations. the total variance of the dataset is the sum of individual variances associated with each principal component. hence addition of every principal component increases the percentage of variance explained. the maximum number of principal components equals the number of variables and all the principal components together explain 100% variance as shown in fig. 1 below. fig. 1: scree plot of the sample data set from wells a,b,c and d principal components correlate well with the variables in the problem, pc1 correlates well with rhob log,nphi log and dt log as shown in fig. 2 consecutively and pc2 may show a good correlation with sfl log and ild log as shown in fig. 3. this indicates that pc1 represents formation porosity while pc2 shows a stronger correlation with resistivity. table 1 shows the eigenvectors of the covariance matrix which represent the coefficients of the pc equations for all pcs and well logs. the first few principal components often explain most of the variance in the dataset and are usually adequate to reveal the structure of the dataset without too much loss of information as shown in fig. 1. by selecting only dahlia abdulhadi abdulateef , ahmed zarzor and mohammed s. al jawad -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 17 the first few principal components for data analysis, one can redu the dimensionality of the problem [3,4,5]. for example in our work, the first two principal components explain over 90% variance of the dataset then by selecting the first two principal components for cluster analysis, the dimensionality of the problem can be reduced from five to two. every principal component is then a coordinate of the data point in a two dimensional space fig. 4 table(1)pca transformation coefficients (eigenvectors) ev2 ev1 variable nphi rhob ild sfl dt the pc transformation coefficients for the first two pc'sare given in eq.(1) and eq.(2)as: pc1= -0.406 nphi + 0.3403rhob + 0.3422 ild + 0.4115 sfl – 0.3222 dt …(1) pc2= -0.0203 nphi 0.5450 rhob 0.5522 ild 0.1706 sfl – 0.5617 dt …(2) fig. 2: scatter plot (pc1 vs nphi, rhob, dt, ild and sfl ) of the sample data set from wells ( a,b,c and d ) electrofacies characterization of an iraqi carbonate reservoir 18 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net fig. 3: scatter plot (pc2 vs nphi, rhob, dt, ild and sfl ) of the sample data set from wells ( a,b,c and d ) fig. 4: scatter plot (pc1 vs pc2) of the sample data set from wells (a,b,c and d) model based cluster analysis (mca) cluster analysis is done for classifying a data set into groups that are internally homogeneous and externally isolated on the basis of a dahlia abdulhadi abdulateef , ahmed zarzor and mohammed s. al jawad -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 19 measure of similarity and dissimilarity between groups. in this study, modelbased clustering technique is used. this approach can give much better performance than traditional procedures of clustering techniques, which are often fail to identify groups that are either overlapping or of varying sizes and shapes. another advantage of model-based approach is that there is an associated bayesian criterion for assessing the model. this provides a means of selecting not only the parameterization of the model, but also the number of the clusters without the subjective judgments [1, 5 and 6]. cluster analysis aims to classify data points into groups based on the unique characteristics of the well log measurements, where input is in the form of petrophysical properties measured at every depth, a cluster represents a collection of samples with similar petrophysical properties which are considerably different from the petro physical properties of the samples from another cluster. cluster analysis was applied to the first two principal components for classifying the data into clusters, as shown in figure 5. the first two principal components pc1 and pc2 show the existence of 4 clusters (e facies). the efacies that was obtained in well a are 1, 2 and 3. in well b only two efacies 3 and 4 was noticed, while in the wells c and d the e-facies are 1, 2, 3 and 4. fig. 5: cluster plot of the first twoprincipal components after model based cluster analysis comparison with geological units results that obtained from efacies characterization were compared with the geological units which also divided the formation into four units (a,b,c and d). the top for each unit that was obtained from the e-facies characterization seems to be too close to the geological units as seen from figures 6, 7, 8 and 9. electrofacies characterization of an iraqi carbonate reservoir 20 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net fig. 6: a comparison between distribution of the four electrofacies groups with respect to depth and geological units for well a 2620 2625 2630 2635 2640 2645 2650 0 1 2 3 4 d e p th ( ft ) efacies well a geological unints 4 cluster without k dahlia abdulhadi abdulateef , ahmed zarzor and mohammed s. al jawad -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 21 fig. 7: a comparison between distribution of the four electrofacies groups with respect to depth and geological units for well b 2685 2690 2695 2700 2705 2710 2715 0 1 2 3 4 5 d e p th (f t) efacies well b geological units 4 clusters without k electrofacies characterization of an iraqi carbonate reservoir 22 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net fig. 8: a comparison between distribution of the four electrofacies groups with respect to depth and geological units for well c 2660 2670 2680 2690 2700 2710 2720 2730 2740 2750 2760 0 2 4 6 d e p th (f t) efacies well c geological units 4 clusters without k dahlia abdulhadi abdulateef , ahmed zarzor and mohammed s. al jawad -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 23 fig. 9: a comparison between distribution of the four electrofacies groups with respect to depth and geological units for well d conclusions  in electrofacies determination by e-facies software, the pca analysis gives convenient visual information for identifying the important components. the first two principal components explain around 90 % variation of the whole sample data set. the first principal component pc1 shows a strong correlation with rhob, dt log and nphi log readings where pc2 shows good correlation with sfl log, ild log and rhob log readings.  pc1 and pc2 are used in mca model-based cluster analysis. the whole data set divided into 2650 2660 2670 2680 2690 2700 2710 2720 2730 2740 2750 2760 0 1 2 3 4 5 d e p th (f t) efacies well d geolodyical unit 4 cluster without k electrofacies characterization of an iraqi carbonate reservoir 24 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net four cluster groups by the mca. each cluster can be treated as an individual electrofacies groups.  the results of the electrofacies characterization show very goodmatch of the tops for various number of units with the actual ones.  electrofacies characterization is a powerful tool to predict lithofacies at wells without core data. nomenclature dt sonic transient time, µsec/ft ev eigenvectors ild deep lateral log, ωm k permeability, md mca model based clustering nphi neutron log derived porosity, fraction pc principal component pca principal component analysis sfl spherically focused log, ωm rhob density log, gm/cc references 1pushpa sharma, g. mamgain, v.k. bahuguna and chaman lal, 2011, improved permeability estimates in carbonate reservoirs using electrofacies characterization: a case study of mumbai high south, the 2nd south asain geoscience conference and exhibition,geoindia 2011. 22i.s. nashawi, a. malallah, 2010, permeability prediction from well logs using fuzzy logic and discriminant analaysis, spe 133209. 33lee s.h., kharghoria a. and datta-gupta a., 1999, electrofacies characterization and permeability predictions in carbonate reservoirs: role of multivariate analysis and nonparametric regression, spe 56658. 4trond mathisen, lee s.h., and datta-gupta a., 2001, estimates in carbonate reservoirs using electrofacies characterization: a case study of the north robertson unit, west texas, spe 70034. 5lee s.h., kharghoria a. and datta-gupta a., 2002, electrofacies characterization and permeability prediction in complex reservoirs, spe 78662-pa. 6bucheb, j. a. and evans, h. b., 1994, some applications of method used in electrofacies identification, the log analyst (jan.-feb. 1994) 14. iraqi journal of chemical and petroleum engineering vol.17 no.4 (december 2016) 105111 issn: 1997-4884 experimental investigation of mass transfer for copper reduction by weight difference technique marwa h. ibrahim and sarmad t. najim chemical engineering department – college of engineering – university of nahrain abstract an experimental analysis was included to study and investigate the mass transport behavior of cupric ions reduction as the main reaction in the presence of 0.5m h2so4 by weight difference technique (wdt). the experiments were carried out by electrochemical cell with a rotating cylinder electrode as cathode. the impacts of different operating conditions on mass transfer coefficient were analyzed such as rotation speeds 100-500 rpm, electrolyte temperatures 30-60 , and cupric ions concentration 250-750 ppm. the order of copper reduction reaction was investigated and it shows a first order reaction behavior. the mass transfer coefficient for the described system was correlated with the aid of dimensionless groups as follows: sh = 3.77 4075 < re < 34088 key words: mass transfer coefficient, electrodeposition of cupric ions, weight difference technique (wdt). introduction in the past years there was a special apprehension for the recovery / removal of copper from different types of waste (waste water with low or high amount of copper, waste printed circuit boards from dismantling electrical and electronic equipment, used batteries, ash from the burning of leftover) [1]. to get rid of large amounts of electronic remainders is causes environmental pollution and loss of precious resources [2, 3]. there are various techniques used for recovery of heavy metals and treatment of dilute metal impure water as a superfluity from mineral processing [4]. contaminants are existing in certain concentrations in the environment as a result of human actions, having a significant negative influence on it. due to the difficulty and the great cost of the methods for their management, a detailed analysis to determine the best techniques for their removal is required. the major sources of contamination with metal ions are the remainders from industrial activities in the following regions [5]:  metallurgy (etching, polishing).  mining (primary output of ores, mine waters).  hydroelectrometallurgy (exhausted electrolytes), istry (depleted electrochemical sources – batteries and accumulators).  electroplating, electrodeposition, (polluted baths). university of baghdad college of engineering iraqi journal of chemical and petroleum engineering experimental investigation of mass transfer for copper reduction by weight difference technique 106 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net  chemistry (catalysts, chemical reagents, dyes).  leather (tanning). it must be revealed that in every industrial unit wastewater encompassing metal ions are attained [5, 6]. metal recovery from recyclable waste is a less energy consuming process than obtaining the metal from raw mineral resources (also taking into consideration the increasing restriction of resources). according [7], metal recycling processes involves diminished radiations of greenhouse gases – thus appreciably participate to the environmental safeguard. water is the basis of survival, the essential obligation for health and vital need for industrial development. this is the most precious item for the humanity. water accessibility is reducing and for this reason it is essential to preserve the water quality. disposal of metal ions from water is a main regard because these pollutants can be collected in humans and their presence clear long-term influences and several illnesses. the common metal ions that have significant influences on human health are cadmium, lead, and copper [8]. all copper compounds are actually poisonous. human can be subjected to copper by air inhalation, and water swallowing. a portion of copper poisonousness is due to the creation of monovalent ions that have the capability to produce greatly interactive free roots. copper can bring illnesses influencing the brain, liver, and neural system. an amount of copper in sea water above acceptable restrictions could destruct marine life. this affects fish and other marine organisms [8]. copper may approach the environment from mines, plantations, industrial plants by wastewater thrown into rivers. copper can be reached also in the air from natural sources such as volcanoes, decomposing plants, and forest fires. drinking water can comprise high amounts of copper if the pipes through which is pumped are made of copper. rivers has been handled with copper composites to govern algae growing, or water seeping from power plants and soils may encompass great content of copper [8]. the aim of the present work is to design and construct a copper recovery cell so as to study the effect of various operating parameters on the mass transfer coefficient. theory mass transfer plays an important role in chemical and electrochemical operations. it is the motion of materials from one situation in the solution to another emerges from variation in concentration, electrical or chemical potential at the two situation. the reaction of cathodic copper deposition is used to study mass transfer at the rotating cylinder electrode (rce) [9]. in general, the mechanism of mass transfer depends upon the dynamics of the system in which it occurs. there are two distinct modes of mass transport, molecular diffusion mass transfer and convective mass transfer, are analogous to conduction heat transfer and convective heat transfer [10]. molecular diffusion mass transport is a slow process in which the transfer of matter is due to random motion, from high concentration region to low concentration region, of stationary molecules by influence of their thermal energy or from fluids moving in laminar flow independent of any convection effects, although it is nevertheless show even in turbulent flow. the net flow of each molecular species occurs in the direction of a negative concentration gradient and http://www.iasj.net/ marwa h. ibrahim and sarmad t. najim -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 107 hence increase the mass transfer rate [10]. convective mass transfer encompasses the transfer of material between a boundary surface and an moving fluid, or between two immiscible moving fluids, this category of transfer based on the transport properties and the dynamic of the flowing fluid. the mechanical agitation has generated fast motion of large portion of fluids called eddies from the position to another. these eddies make transport in turbulent region more rapid than in laminar region [10]. by retaining to the fick's first law which is used to define mass transfer rate (flux): nj=kmδ …(1) km = it is obviously clear that by calculating the mass transfer rate and the difference in the concentration δ , the mass transfer coefficient can be determined. can be calculated by dividing the weight of the specimen before and after the experiment ( ) by the area of specimen, time of experiment, and atomic weight of copper as shown by the following equation: = …(2) δ can be measured from knowing the cupric ions concentration before experiment , and the cupric ions concentration after experiment which was calculated by atomic absorption device, type analytikjena, german origin. for the recovery of cu +2 in electrolyte contain h2so4, under convection, mass transfer can be described by a dimensionless group correlation of the following expression [11]: sh=are b sc 0.356 …(3) experimental work 1. materials in this study the electrolyte solution used was composed of:  annular grade sulfuric acid provided by sd fine–chem limited company (purity > 98 wt%, sp.gr. 1.84) is used. sulfuric acid is diluted by distilled water to prepare 0.5m h2so4 solution.  copper sulfate petahydrate (cuso4.5h2o) provided by roma company is used as redox system to give various concentrations of cupric ions 250, 500, and 750 ppm. 2. cell and circuit the experimental apparatus which were used for performing the present work is shown in figure 1. the cell consisted of beaker of capacity 2 liter, the anode was a compressed graphite cylindrical bar (insoluble) is an electrical conductive material used for copper recovery, which had 28 mm diameter and 15 cm length, rotating cylinder electrode (rce) used as the working electrode (cathode) made of copper having 25 mm outside diameter and 20mm inside diameter and 3.2cm length. the rest of rotating electrode (shaft) was made of teflon the distance between electrodes is 3cm. the electrical circuit consisted of 6v dc power supply, connected in a series with cell and ammeter. a voltmeter was connected in parallel with the reference electrode and cathode. http://www.iasj.net/ experimental investigation of mass transfer for copper reduction by weight difference technique 108 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net 1. rotating shaft, 2. working electrode (specimen), 3. graphite electrode (anode), 4. beaker, 5. water bath, 6. reference electrode (sce), 7. digital stirrer, 8. thermometer, 9. power supply, 10. resistance box, 11. voltmeter, 12. ammeter, 13. luggin capillary tip, 14. brush, 15. stand, 16. electric wires. fig. 1: schematic diagram of experimental setup 3. electrochemical reaction in this stud the reduction of cupric ions was considered as shown in the following equation in order to determine km for this process with the aid of weight difference technique. cu +2 + 2e cu …(4) results and discussion table 1 shows the determined mass transfer coefficient km by weight difference technique under different operating conditions. figure 2 describe the effect of rotation rate on mass transfer coefficient km calculated by wdt. it is clear from these figures that by increasing the rotation rate resulting in rises km as presented for a given temperature. this can be ascribed to the increase in the transfer rate of cupric ions near to the electrode surface by eddy transport. increasing velocity leads to decrease the diffusion layer thickness at the surface due to eddies break through diffusion layer diminishing its thickness which exhibits the attraction resistance to copper transfer [12]. table 1: km by wdt under different operating conditions t, rotation rate (rpm) (cm/s) for 250 ppm cu +2 (cm/s) for 500 ppm cu +2 (cm/s)for 750 ppm cu +2 30 100 4.266196 4.315825 6.247023 200 5.297857 5.832570 7.481934 300 6.515114 7.894590 8.971969 400 8.040995 9.870073 10.86129 500 8.916118 11.21638 12.67958 45 100 4.670039 5.891485 7.294601 200 5.770343 7.535745 8.357544 300 7.281437 9.178956 10.13139 400 8.692206 10.73127 11.88552 500 9.527953 11.68249 14.10500 60 100 5.465652 6.837334 8.253200 200 7.320438 8.681214 10.31207 300 8.624342 9.951418 12.00958 400 10.59190 11.61391 13.82989 500 11.68399 12.61508 15.02930 100 200 300 400 500 rotation rate (rpm) 0.004 0.005 0.006 0.007 0.008 0.009 0.01 0.011 0.012 0.013 m a ss t r a n sf e r c o e ff ic ie n t, k m ( c m /s ) cb = 250 ppm cu +2 30 oc 45 oc 60 oc fig. 2: km vs. rotating rates at different temperatures for electrolyte containing 250 ppm cu +2 it is obvious from figure 3 that as of the temperature increases km increases. this is due to the fact that by increasing temperature it will accelerate reaction rate. furthermore, increasing temperature will increase the diffusion coefficient of electroactive species (cupric ions) [12, 13], which causes a slight increase in solution conductivity and decreases the viscosity and hence increase the diffusion rate of cupric ions to the electrode surface [14]. it can be presented from figure 4 that increasing cupric ions http://www.iasj.net/ marwa h. ibrahim and sarmad t. najim -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 109 concentration leads to increase the mass transfer coefficient. this can be attributed to the fact that by increasing the cupric ions it will increase the driving force (concentration difference) and in the same time it will increase the electrical conductivity of solution and lowerers the solution resistivity for the current flowing between electrodes, i.e. this assists the copper removal from solution and its precipitated on cathode [14]. 30 40 50 60 electrolyte temperature (oc) 0.003 0.006 0.009 0.012 0.015 m a ss t r a n sf e r c o e ff ic ie n t, k m ( c m /s ) cb = 250 ppm cu +2 100 rpm 200 rpm 300 rpm 400 rpm 500 rpm fig. 3: km vs. electrolyte temperatures at different rotation rates for electrolyte containing 250 ppm cu +2 200 300 400 500 600 700 800 cupric ions concentration (ppm) 0.004 0.008 0.012 0.016 m a ss t r a n sf e r c o e ff ic ie n t, k m ( c m /s ) t = 30 oc 100 rpm 200 rpm 300 rpm 400 rpm 500 rpm fig. 4: km vs. cupric ions concentration at different rotation rates and 30 figure 5 displays the plot of log sh/sc 0.356 vs. log re at various operating conditions for wdt technique, an upright line was obtained, its slope is b, while the intercept is a. from the above figures a and b were found for wdt technique as presented in the following equation: sh=3.77 …(5) for the range 4075 < re < 34088 figure 6 presents cupric ions concentration against time so as to examine the order reaction for copper reduction. it can be seen from the above figures that the concentration of cupric ions decreased in a nonlinear way, so the reduction reaction of copper which is under mass control is first order reaction and that is a good agreement with [15] as show in figure 7. it can also be observed that removal of cupric ions increased with increasing rotation rates and electrolyte temperature. for a constant temperature, it can be noticed the removal of cupric ions was achieved at 500 rpm higher than at 100 or 300 rpm due to the increase in rotation rate resulting in rising the copper reduction rate. 3.6 3.8 4 4.2 4.4 4.6 log re 2.2 2.3 2.4 2.5 2.6 2.7 2.8 lo g s h /s c 0 .3 5 6 cb = 250 ppm cu +2 30 oc 45 oc 60 oc fig. 5: the relation between log sh/sc 0.356 against log re for electrolyte solution contains 250 ppm cu +2 0 15 30 45 60 time (min) 175 200 225 250 c u p r ic i o n s c o n c e n tr a ti o n s (p p m ) t = 30 oc 100 rpm 300 rpm 500 rpm fig. 6: cu +2 concentrations against time for electrolyte contains 250 ppm cu +2 at 30 http://www.iasj.net/ experimental investigation of mass transfer for copper reduction by weight difference technique 110 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net fig. 7: behavior of a variable-order reaction [15] conclusions 1. the most effective parameter on km is the rotation rate and the smallest effective parameter is the cupric ions concentration. 2. the reduction reaction of copper is a first order reaction. 3. the mass transfer coefficient increased with the increasing in electrolyte temperature for both techniques. 4. rce proved useful for rapid heavy metal ions removal studies. nomenclature a = cathode area, cm 2 a = constant used in eq. 3 b = constant used in eq. 3 co = initial concentration of cupric ions, mol/cm 3 cf = final concentration of cupric ions, mol/cm 3 d = diameter, cm d = diffusion coefficient, cm 2 /s km = mass transfer coefficient, cm/s nj = diffusional flux of electroactive species, mol/s.cm 2 re = reynold number, u d/v sh = sherwood number, km d/d sc = schmidt number, v/d t = temperature, u = velocity, cm δc = concentration difference between initial concentration and final concentration, mol/cm3 v = kinematic viscosity of cupric ions, cm 2 /s references. 1. imrelucaci i.f., popescu l.c. and ileu i.p., (2011), “electrochemical methods for recover of copper from waste waters and solid wastes”, ph.d. thesis, babes-balyai university. 2. jha m.k., gupto d., choubey p.k., kumar v., jinkijeong, and lee j., (2014), “solvent extraction of copper, zinc, cadmium and nickel from sulfate solution in mixer settler unit (msu)”, separation and purification technology, vol. 122, pp. 119-127. 3. chen m., huang j., ogunseitan o., zhu n., wang y., (2015), “comparative study on copper leaching from waste printed circuit boards by typical ionic liquid acids”, waste mangement, vol. 41, pp. 142-147. 4. figueroa l., and wolkersdorfer c., (2014), “electrochemical recovery of metals in mining influenced water: state of the art”, an interdisciplinary response to mine challenges-sui, sun & wang (eds). 5. kuhn, a. t., 1971, industrial electrochemical processes, elsevier, amsterdam. 6. walsh f.c., reade g.w., (1994). “electrochemical technique for the treatment of dilute metal-ion solution in studies in environmental science 59, environmental oriented electrochemistry”, c.a.c. sequeira, elsevier, amsterdam. 7. damgaard a., larsen a.w., and christensen t.h., (2009), “recycling metals: accounting of greenhouse gases and global warming contributions”, waste mangment &research, vol. 27, pp. 773-780. 8. lossin a., (2002), copper, volume 10 of ulmann's encyclopedia of industrial chemistry, wiley-vch verlag gmbh. http://www.iasj.net/ marwa h. ibrahim and sarmad t. najim -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 111 9. asano k., (2006), “mass transfer fundamentals to modern industrial applications”, wiley-vch verlag gmbh & co. kgaa, pp. 325. 10. benitez j., (2009), “principles and modern applications of mass transfer operations”, john wiley & sons, inc., 2 nd edition. 11. rivera f.f. and nava j.l., (2007), “mass transport studies at rotating cylinder (rce) influence of using plates and concentric cylinder as counter electrodes”, electrochemical acta. 12. shen c., afacan a., luo j., and klimas s.j., (2014), “mass transfer of dissolved oxygen using rotating cylinder electrode under bulk boiling condition”, international journal of heat and mass transfer, vol. 70, pp. 162-168. 13. theordore l., and ricci f., (2010), “mass transfer operations for the practicing engineering”, john wiley & sons, inc. 14. ntengwe f.w., (2008), “the effect of impurities, smootheners and other factors on the recovery of copper from solutions”, m.sc. thesis, south africa university. 15. kaminari n.m.s., ponte m.j.j.s. and ponte h.a., (2010), “mass transfer correlation for the removal of copper ions from wasteater”, engenharia te'rmica (thermal engineering), vol. 9, pp.63-68. http://www.iasj.net/ iraqi journal of chemical and petroleum engineering vol.16 no.2 (june 2015) 4552 issn: 1997-4884 preparation and characterization of y2o3, sio2 doped by eu2o3 as luminescent ink amel salih merzah and abdulrahman saleh ibrahim technical college-baghdad abstract this article includes the preparation of luminescence materials from rare earth (eu ) ion doping yttrium oxide (y2o3) 70% and sio2 25% and study the characteristics of phosphors for ultraviolet to visible conversion. the phosphor materials have been synthesized by two steps: preparing the powder by solid state method using y2o3, sio2 and eu2o3 with doping materials concentration (70%, 25% and 5%) respectively and different calcination temperature (1000, 1200 and 1400 o c). the second step is to prepare the colloid solution by dispersing the produced powder in a polyvinyl alcohol solution (4%) . powder preparation is achieved by mixing the powder according to weight percentage, milling by a ball mill using yttrium stabilized zirconia with the aid of propanol for homogenization then calcination the mixture at the above temperatures. the produced powder was characterized by x-ray diffraction. colloid preparation is achieved by dissolving the pva in water (4%) then dispersing the powder into the solution by using the hot plate magnetic stirrer and ultrasonic bath. the produced powder was characterized by using fourier transform infrared (ftir) and photoluminescence spectra (pl). the results of photoluminescence spectra show that samples were emitting red color with wave length of 612nm. the intensity of emission was increased with increasing calcination temperature. key words: luminescence, b. solid state reaction, c. x-ray diffraction. introduction luminescence is a collective term for the different ways in which substance emits visible light under the influence of certain radiation with the exception of pure heat. also it was defined as the phenomenon of emission of light from various phosphor materials. luminescence involves the excitation and subsequent relaxation of the valence electrons from there excited state. luminescence is general terms of both phosphorescence and fluorescence [1]. phosphorescence is a slow process in which emission continues for a few seconds, minutes or even hours after removing the excitation, whereas fluorescence is fast process in which emission stops abruptly after turning off the excitation [2]. in recent years, considerable research has been done on the synthesis and characterization of large band gap iraqi journal of chemical and petroleum engineering university of baghdad college of engineering preparation and characterization of y2o3, sio2 doped by eu2o3 as luminescent ink 46 ijcpe vol.16 no.2 (june 2015) -available online at: www.iasj.net oxide materials (wide-bandgap" refers to higher voltage electronic bandgaps significantly larger than one electronvolt ev. the exact threshold of "wideness" often depends on the context, but for common usage, "wide" bandgap typically refers to material with a band gaps of at least three ev)[3] such as y2o3 and sio2 doped with rare-earth elements using different chemical methods such as sol-gel precipitation and combustion[4]. there are many advantages of luminescent materials, precise material deposition on substrate at well-defined positions, small material consumption, less material losses and it has excellent chemical stability [1]. zhou kai et al (2011), had presented a study on the effect of heat treatment on structure and up conversion emission of er +3 doped gaf3 / inf3 based fluoride glasses. gaf3 / inf3 based oxyfluoried glasses were obtained by melt quenching method. they found that the intensity of green luminescence significantly increased in transparent glass-ceramic until the content of er +3 reaches 2 mol.% compared to that in as –prepared, but without increasing linearly with the increasing time[5] . wang chaonan et al, had presented a study on the influence of synthetic condition(ph value of the precursor solution ) on properties of y2o3 : eu +3 nano phosphors by auto combustion method ,they indicate that samples prepared under high ph value have stronger luminescence intensity revealed by emission, samples with decreased ph value show a red shift and the decay curve show shorter lifetime with the increase of crystalline size [6]. there are many applications of luminescent materials which can be used in many fields, security ink, widely used in cathode ray tube displays [7], plasma display panel[8], high radiation energy detection (such as to make films for x-ray detection) applications[9] and white light emitting diode (led)[10] the aim of this work is to prepare luminescent ink from rare earth materials by solid state method which is the most widely used method for the preparation of polycrystalline solids from a mixture of solid starting materials. solids do not react together at room temperature over normal time scales and it is necessary to heat them to much higher temperatures, often from 1000 to 1500°c in order for the reaction to occur at an appreciable rate. the factors on which the feasibility and rate of a solid state reaction include, reaction conditions, structural properties of the reactants, surface area of the solids, their reactivity and the thermodynamic free energy change associated with the reaction[11]. experimental the experimental part is performed by two steps the first is the preparation of the powder of y2o3, sio2: eu2o3 and the second step is preparation of the pva colloid. materials used in the present work with their properties and sources are listed in table (1) below. table 1, raw materials and the properties item purity source characterization y2o3 99.9% sigma aldrich nano powder <50nm sio2 99.5% sigma aldrich nano powder <50nm pva 99% sigma aldrich n=8900098000 eu2o3 99.5% sigma aldrich nano powder <150nm y2o3, sio2: eu2o3 powder preparation the powder is prepared by using solid state reaction. the starting amel salih merzah and abdulrahman saleh ibrahim -available online at: www.iasj.net ijcpe vol.16 no.2 (june 2015) 47 materials and weights are listed in table (2): table 2, the percentages of starting materials batch no. item weight percentage % weigh t (g) 1 y2o3 sio2 eu2o3 70 25 5 4.142 0.393 0.461 raw materials were weighed according to the above table in an electronic balance (five digits) inside a nanofiltration system which shown in figure (1). fig. 1, nano-filtration system (which conducted in laboratories of sheffield hallam university). the powders were fed in a poly vinyl chloride bottles with balls made from yttrium stabilized zirconia (ysz) as milling media, then the mixture was milled by using a ball mill for 24 hrs with 64.5 rpm, this process was performed with the addition of propanol to achieve homogenization. after 24hr the mixture was poured inside stainless steel pan then dried in a carbolite dryer for 4hr in 80 ◦ c to evaporate propanol. the dried sample was calcined in an naberthem furnace (which conducted in laboratories of sheffield hallam university) using an alumina crucible as a boat at a temperatures of 1000, 1200 and 1400 ◦ c for 9 hrs. the powder after calcination was milled again in the same previous way for 24 hrs with 64.5 rpm in order to prevent agglomeration. xray diffraction was used to characterize the powder after preparation by solid state method. colloid preparation to prepare the security ink, the powder was produced as colloid, this can be achieved by dispersing the powder in a poly vinyl alcohol [ch2choh] n, (n=89000-98000) inside a nano-filtration system. first a solution of polyvinyl alcohol in water (4%) was prepared with the aid of revotherm magnetic stirrer, homogenizer and heater which shown in fig. (2). fig. 2, magnetic stirrer, homogenizer and heater. 0.2 g of the powder was added to 20 ml of pva solution. the suspension was also mixed and heated in a revotherm magnetic stirrer and homogenizer with heating up to 50 ◦ c for 1 hr .then mixing without heating for 2 hrs with the addition of 10 ml ethanol , a kerry ultrasonic bath(which conducted in laboratories of sheffield hallam university) was used for the third stage mixing and homogenization ,then the fourth stage of mixing and homogenization was achieved by magnetic stirrer and preparation and characterization of y2o3, sio2 doped by eu2o3 as luminescent ink 48 ijcpe vol.16 no.2 (june 2015) -available online at: www.iasj.net homogenizer for 2 hrs, the final product was a white solution which then tested by photoluminescence spectra and fourier transform infrared. characterization the characterization of powder was achieved by x-ray diffraction. the x-ray powder diffraction patterns presented in this work were measured in laboratories of sheffield hallam university using a theta to theta diffractometer (philips), equipped with a cu kα source (generator: 40 kv and 40 ma) with wave length of 1.5418a, a scintillation detector with pulse-height analysis, and a variable knife-edge collimator for high resolution x-ray diffractometry. the best achievable instrumental resolution was 0.001° in 2θ. colloid characterization the prepared colloid characterization was achieved by measuring its photoluminescence spectra, in order to predict its capability to emit color (luminescence). photoluminescence spectra photoluminescence spectra is measured by using fluoro max-4 spectrofluorometer in laboratories of sheffield hallam university. the excitation wave length for all samples were 254 nm (at the ultraviolet region) produced by xenon flash lamp then the emitted wave was detected by signal detector (photomultiplier tube and housing). fourier transform infrared fourier transform infrared is measured by nexus ftir in laboratories of sheffield hallam university. the variables of the instrument was number of scan: 64 resolution: 4 data spacing: 1.928cm -1 results and discussion x-ray diffraction the analyses of x-ray diffractions for all synthesized samples were shown below according to their concentration and calcination temperature: figures (1), (2) and (3) shows the powder xrd patterns of the ysi:eu powder with calcination temperature at 1000,1200 and 1400 o c indicate that a cubic structure of y2o3:eu was produced corresponding to the planes and 2θ. as shown in table (3): table 3 planes(h k l) 2θ (degree) (211) 20.53 (222) 29.18 (400) 33.81 (411) 35.92 (420) 37.91 (431) 43.49 (440) 48.54 (611) 53.21 (622) 57.59 when compared with international center for diffraction data (icdd) card no. 25-1011 of cubic (y0.95eu0.05)2o3[12]. there is peaks comes from sio2. amel salih merzah and abdulrahman saleh ibrahim -available online at: www.iasj.net ijcpe vol.16 no.2 (june 2015) 49 fig. 3, xrd patterns for system y si eu calcined at1000 ◦ c fig. 4, xrd patterns for system y si eu calcined 1200 ◦ c fig. 5, xrd patterns y: si eu calcined 1400 ◦ c fourier transform infrared the analysis of fourier transform infrared for all synthesized colloid is shown in figures (6) , (7) and (8) can be discussed by comparing it with the data of infrared absorption of pure materials according to the wave number. the broad peak at around 3340 cm -1 is originated from o-h stretching in hydroxyl groups. both pva and alcohol contain hydroxyl group. c-h stretching was observed at around 2980 cm -1 . peak at around 2300-2400cm -1 is formed from c≡c group. the peak at around 1600-1800 cm -1 was from c=o group. absorption peak at around 1213-1420 cm -1 might originated from c-h bend and c-c stretching. c-o stretching was observed at around 1020-1100 cm -1 . the absorption peak at around 8901000cm -1 was originated from interaction between pva chain of the solution and the surface of y2o3, sio2 :eu2o3 powder. figures for all samples are shown below according to the concentration and calcination temperature. fig. 6, the ftir system of y si eu calcined at 1000 ◦ c. preparation and characterization of y2o3, sio2 doped by eu2o3 as luminescent ink 50 ijcpe vol.16 no.2 (june 2015) -available online at: www.iasj.net fig. 7, the ftir of system y si eu calcined at 1200 ◦ c. fig. 8, the ftir of system y si eu calcined at 1400 ◦ c. photoluminescence spectroscopy the analysis of photoluminescence spectroscopy for all synthesized colloid are shown below according to the concentration and calcination temperature as shown in figures (9, 10 and 11). from figure (9) below there are three peaks, the first one at wave length 508 nm it comes from 2λ( where the applied λ was 254 nm. the second tiny peak at wave length 612 nm from electron transition in eu +3 ion from 5 d0→ 7 f2 (d,f represent energy level) and this peak represent the luminescent of sample which calcined at 1000 ◦ c but it has low intensity when compared with the other two samples.the third peak at wave length 760 nm from 3λ (where λ is the applied wave length) . fig. 9, photoluminescence spectra of y si eu calcined at 1000 ◦ c. from figure (10) below there are five peaks, the first peak at wave length 508 it comes from 2λ where the applied λ was 254 nm , the second peak at wave length 585 nm comes from electron transition in eu +3 ion from 5 d0→ 7 f1 . the third peak at wave length 612 nm comes from electron transition in eu +3 ion from 5 d0→ 7 f2. fig. 10, photoluminescence spectra of y si eu 5% calcined at 1200 ◦ c. the fourth peak at wave length 700 nm comes from electron transition in eu +3 ion from 5 d0→ 7 f3 (d,f represent energy level) . the fifth peak at wave length 760 nm it comes from 3λ (where λ is the applied wave length).the thired peak is represent the amel salih merzah and abdulrahman saleh ibrahim -available online at: www.iasj.net ijcpe vol.16 no.2 (june 2015) 51 emission (luminescence) of this sample which calcined at 1200 ◦ c and it is higher in intensity than sample calcined at 1000 ◦ c from figure (11) below there are four peaks, the first one at wave length 585 nm comes from electron transition in eu +3 ions from 5 d0→ 7 f1. the second peak at wave length 612 nm comes from electron transition in eu +3 ion from 5 d0→ 7 f2 and this peak is represent the luminescence of sample calcined at 1400 ◦ c ,it has higher intensity when compared with the other two samples. photo luminescence intensity increased with increasing calcination temperature. the third peak at wave length 700 nm comes from electron transition in eu +3 ion from 5 d0→ 7 f3 . the fourth peak at wave length 760 nm it comes from 3λ. fig. 11, photoluminescence spectra of y si eu 5% calcined at 1400 ◦ c. conclusion stable luminescent colloid was produced from y2o3,sio2:eu powder dispersed in poly vinyl alcohol solution. y2o3,sio2:eu played a major role as luminescent centers in the colloid which emitted red luminescence. this colloid can meet several applications in optoelectronics such as for production of light emitting devices, light sensor, and luminescent displays in a very definitive sizes and shapes. in this work the colloid used as luminescent ink to print the valuable document and saving it from fake by writing it on a white paper, this cannot be read until applying ultraviolet light, then the wrote document will appear in red color. increasing calcination temperature of the powder lead to increase luminescent intensity of the emission. references 1arunachalam lakshmanan(2008) , luminescence and display phosphors phenomena and applications, nova science publisher , qc476.7.l85, new york. 2o.m. ntwaeaborwa, "sol-gel synthesis and luminescent properties of pr 3+ in different host matrices", phd dissertation, . university of the free state, south africa, 2006. 3shen, shyh-chiang, wide-bandgap device research and development at srl, georgia institute of technology semiconductor research laboratory, retrieved 2014-09-03. 4d.h aguilar, l.c torres-gonzalez and l.m torres-martinez (2000), a study of the crystallization of zro2 in the sol–gel system: zro2–sio2 ,journal of solid state chemistry 349-357. 5zhou kai , zhu jigian, zeng jie and liu junfang, " effect of heat treatment on structure and upconversion emission of er +3 – doped gaf3 / inf3 based fluoride glasses", rare metals , vol. 30 , p. 121 (2011). 6wang chaonan , wang zhifang , zhang weiping , min yin, "influence of synthetic condition on properties of y2o3: eu 3+ preparation and characterization of y2o3, sio2 doped by eu2o3 as luminescent ink 52 ijcpe vol.16 no.2 (june 2015) -available online at: www.iasj.net nanophosphors”, http://www.paper.edu.cn, no. 10774140. 7astuti,mikrajuddin abdullah, and khairurrijal (2009) , " synthesis of luminescent ink from europiumdoped y2o3 dispersed in polyvinyl alcohol solution" , hindawi publishing corporation, article id 918351. 8yu-chun li, yen-hwei chang, yufeng lin, yee-shin changb and yijing lin (2007) , synthesis and luminescent properties of ln 3+ (eu 3+ , sm 3+ , dy 3+ )-doped lanthanum aluminum germanate laalge2o7 phosphors, elsevier, journal of alloys and compounds 439 367–375. 9m. abdullah, k. okuyama, i. w. lenggoro, and s. taya (2005), “a polymer solution process for synthesis of (y,gd)3al5o12:ce phosphor particles,” journal of non-crystalline solids, vol. 351, no. 8-9, pp. 697–704. 10yen, w.m.; shionoya, s.; yamamoto, h.(2007), phosphor handbook, 2nd ed.; crc press/taylor and francis: boca raton, fl, usa. 11anthony r. west, solid state chemistry and its applications", wiley and sons, 2005. 12abdulrahman saleh ibrahim(2014) , " preparation and characterization of rare earth doped luminescent compounds", msc thesis , technical college baghdad / foundation of technical education. http://www.paper.edu.cn/ ijcpe vol.11 no.3 (september 2010) 9 iraqi journal of chemical and petroleum engineering vol.11 no.3 (september 2010) 9 – 14 issn: 1997-4884 treating the used automobiles oils using solvents ghiyath a. r. rassoul and laith s. mahmmoud chemical engineering department, college of engineering, university of baghdad abstract used automobile oils were subjected to filtration to remove solid material and dehydration to remove water, gasoline and light components by using vacuum distillation under moderate pressure, and then the dehydrated waste oil is subjected to extraction by using liquid solvents. two solvents, namely n-butanol and n-hexane were used to extract base oil from automobile used oil, so that the expensive base oil can be reused again. the recovered base oil by using n-butanol solvent gives (88.67%) reduction in carbon residue, (75.93%) reduction in ash content, (93.73%) oil recovery, (95%) solvent recovery and (100.62) viscosity index, at (5:1) solvent to used oil ratio and (40 oc) extraction temperature, while using nhexane solvent gives (60.25%) reduction in carbon residue, (76.54%) reduction in ash content, (89.06%) oil recovery, (94.78%) solvent recovery and (100.3) viscosity index, at (6:1) solvent to used oil ratio and (50 oc) extraction temperature. introduction there are many possible processes to regenerate base oil from used oil. the unused oil contain (71-96 wt. %) base oil, and the rest were additives juma [1]. there are many types of additives some of them contain metal and others are high molecular weight hydrocarbons. during automobile running, some of the above chemicals will be broken down or cracked to smaller molecules. it is essential to remove most carbon residue, ash content, sludge and increase the obtained base oil viscosity index and improve base oil color. economic plays a great role in deciding the type of the solvent used and the operation process. the process may vary from country to country. it depends on the type of origin base oil and type of some of the previous used solvents are alcohols, organics acids, organic bases and n-methyl-2-pyrrolidone (nmp) dturnell [2], u. s. patent no. 6117309 [3], whisman [4]. university of baghdad college of engineering iraqi journal of chemical and petroleum engineering treating the used automobiles oils using solvents 10 ijcpe vol.11 no.3 (september 2010) in order to extract base oil from used oil, many solvents were studied. some of solvents were expensive, and others were cheap but not efficient in improving extract base oil properties. different solvents or, combination of solvents at different temperatures and solvent to used oil ratio were reported. the aim of this research is to select a solvent that can be able to extract the base oil from automobile used oil without causing adverse effects on the physical properties of the solvent and of the extracted base oil, and can be recycled and used again continuously. experimental work materials feed stock the used lubricating oils are collected directly from different automobiles, small saloon cars (internal combustion engine) at different operating conditions. table 1 shows the determined properties of the used lubricating oils. table 1 properties of the used lubricating oils. specification values astm specific gr. @ 60/60 °f 0.897 d1298-77 viscosity, cst, @ 40°c 69.84 d445-83 viscosity, cst, @ 100°c 8.5 d445-83 viscosity index 90.2 d227-79 ip 226/80 ash wt.% 0.81 d482-80 carbon res. wt.% 5.12 d524-76 water wt.% 1.5 by distillation flash point, oc 158 d97-77 solvents two solvents were used in this work. these solvents are n-butanol (hopkin &williams chadwell heath essex, england) and n-hexane (gainland chemical company, u.k.). table 2 shows the manufactures properties of these solvents. table 2 properties of n-butanol and nhexane. specification nbutanol nhexane molecular weight 74.12 86.17 specific gravity @ 60/60 of 0.81 0.659 boiling point, °c 117 69 freezing point, °c -79.9 -94 purity 95% 95% experimental procedure in order to remove water, gasoline and light component from used oil. the used oil was dehydrated initially under vacuum pressure (40 mbar), and at (200° c), using vacuum distillation unit as shown in fig. 1. the obtained dehydrated used oil was subjected either to vacuum distillation or to extraction base oil from used oil by selected solvent (n-butanol or n-hexane). the dehydrated used oil was carried out by vacuum distillation unit by using vacuum pressure (5, 10 and 15 mbar). after each experiment, the vacuum distillation apparatus was washed with n-hexane solvent in order to remove any contaminants that accumulated in the unit. after washing all connections and joints, they were re-lubricated, and prepared for next experiment. for n-butanol, the operating conditions are extraction temperature range from (30 to 60°c), solvent to used oil ratio from (1:1 to 5:1 vol. /vol.). n-butanol is alcohol solvent. it is liquid at normal condition. it is used to dissolve the base oil that presence in used oil and separate it from contaminants by settling, were become two layers as shown in fig. 3. the top layer was the n-butanol and base oil, while the bottom layer was contaminants and small amount of n-butanol and oil. the upper layer was ghiyath a. r. rassoul and laith s. mahmmoud ijcpe vol.11 no.3 (september 2010) 11 separated from lower layer. then the solvent was separated from extract oil by using distillation unit. the solvent and extract oil were re-weighted to make material balance. for n-hexane, the operating conditions are extraction temperature range from (30 to 60°c), solvent to used oil ratio from (2:1 to 6:1 vol. /vol.). n-hexane is aliphatic solvent. it is liquid at normal condition. it is used to dissolve the base oil that presence in used oil and separate it from contaminants by settling, were become two layers. the top layer was the n-hexane and base oil, while the bottom layer was contaminants and small amount of n-hexane and oil. the upper layer was separated from lower layer. then the solvent was separated from extract oil by using distillation unit. the solvent and extract oil were re-weighted to make material balance. fig. 1 flow diagram of the vacuum distillation unit. fig. 2 photos of laboratory vacuum distillation unit. fig. 3 photo of the laboratory extraction unit. results and discussion vacuum distillation in order to separate the base oil from the used oil, vacuum distillation at (5, 10 and 15 mbar) was carried out. the experimental results indicated, as the vacuum pressure increased, from (5 to 15 mbar), the oil recovery decreased from (77.9 to 75.2 wt. %), and the carbon residue reduced from (87 to 86 wt. %), and ash content reduced from (74.8 to 73.5 wt. %), respectively, as shown in fig.4. 70 75 80 85 90 5 mbar 10 mbar 15 mbar vacuum pressure w e ig h t p e r c e n t p r o d u c t oil recovery carbon reduction ash reduction fig. 4 vacuum pressure vs. weight percent product. solvents extraction n-butanol solvent extraction the experimental results indicated, increasing in percent of oil recovery with increasing of solvent to used oil ratio at different temperature. the ratio of solvent to used oil were from (1:1 to 5:1 vol. /vol.), while the studied temperatures were from (30 to 60° c). the results indicate an increasing in oil recovery from used oil from (88.6 to 93.7 wt. %), when solvent to used oil ratio increase five times. the higher the solvent quantities the more recovery oil was obtained till to (5:1 vol. treating the used automobiles oils using solvents 12 ijcpe vol.11 no.3 (september 2010) /vol.) solvent to oil ratio. higher solvent to used oil ratio gave unnoticeable change in oil recovery because the solvent recovered most of the base oil and no longer can remove small quantities of base oil, as shown in fig. 5. similar results were obtained for solvent recovery as shown in fig. 6. fig. 5 effects of solvent to used oil ratio on the percent of oil recovery at different extraction temperatures for extraction by nbutanol. fig. 6 effects of solvent to used oil ratio on the percent of solvent recovery at different extraction temperatures for extraction by nbutanol. the results indicated that at (40° c) gave best oil recovery, and at (50° c) gave less oil recovery, while (60° c) gave even less oil recovery then (50° c). this means an increasing in oil recovery from (30° c up to 40° c) and then decreasing in oil recovery from (40° c to 60° c) as shown in fig. 2. similar behavior was obtained for solvent recovery, as shown in fig. 3. where (93.7 wt. %) oil recovery and (95 wt. %) solvent recovery, at (40° c) when solvent to used oil ratio was (5:1 vol. /vol.). similar results were obtained for carbon residue reduction. the results indicated higher carbon residue reduction with increasing solvent to used oil ratio. temperature gave similar behavior as the results indicated (40° c) which gave the best percent carbon residue reduction. the best obtained carbon residue reduction is (88.6 wt. %), as shown in fig. 7 percent ash content reduction increases with increasing solvent to used oil ratio till it reaches an optimum value at (5:1 vol. /vol.). after that the solvent to used oil ratio will not affect on the percent ash content reduction. similarly high temperature will increase percent ash content reduction up to (40° c). higher temperature than (40° c) will decrease percent ash content reduction. the best obtained percent ash content reduction is (75.9 wt. %), as shown in fig. 8. the viscosity index indicates different behavior than the above mentioned parameters, since at (60° c) gave better results than at (40° c). the viscosity index increased from (96.4 to 102.6) at solvent to used oil ratio (1:1 to 5:1 vol. /vol.) and at (60° c) as shown in fig. 9. fig. 7 effects of solvent to used oil ratio on the percent of carbon residue reduction at different extraction temperatures for extraction by n-butanol. ghiyath a. r. rassoul and laith s. mahmmoud ijcpe vol.11 no.3 (september 2010) 13 fig. 8 effects of solvent to used oil ratio on the percent of ash content reduction at different extraction temperatures for extraction by n-butanol. fig. 9 effects of solvent to used oil ratio on the viscosity index at different extraction temperatures for extraction by n-butanol. n-hexane solvent extraction increasing the solvent to used oil ratio will increase the percent of oil recovery. it was found that (6:1 vol./vol.) solvent to used oil ratio will be the optimum ratio in order to obtain high percent of oil recovery (i.e. 89 wt.%). it was found not at (40° c) but (50° c) gave higher percent of oil recovery, as shown in fig. 10. the result also indicated high temperature gave lower percent of oil recovery. solvent recovery increase with increase solvent to used oil ratio, as shown in fig 11. the percent of solvent recovery increased from (84.8 wt.% to 94.7 wt.%) when solvent to used oil ratio increased from (2:1 to 6:1 vol./vol.). the optimum temperature was found to be (50° c), where it gave best percent of solvent recovery. high temperature above (50° c) will decrease percent of solvent recovery, as shown in fig. 8. percent carbon residue reduction and percent ash content reduction were shown in figs. 12 and 13. similar result was obtained for high temperature up to (50° c) and for higher solvent to used oil ratio up to (6:1 vol. /vol.). these results indicate percent carbon residue reduction and percent ash content, which were (2.035 wt.% and 0.19 wt.%) respectively. from initial carbon content and ash content of (5.12 wt. % and 0.81 wt.%) respectively. the viscosity index indicates different behavior than the above mentioned parameter. since at (60° c) gave better results than at (50° c). the viscosity index increased from (94.5 to 101.2), at (60° c) and at solvent to used oil ratio (2:1 to 6:1 vol. /vol.) respectively, as shown in fig. 14. fig. 10 effects of solvent to used oil ratio on the percent of oil recovery at different extraction temperatures for extraction by nhexane. fig. 11 effects of solvent to used oil ratio on the percent of solvent recovery at different extraction temperatures for extraction by n-hexane. treating the used automobiles oils using solvents 14 ijcpe vol.11 no.3 (september 2010) fig. 12 effects of solvent to used oil ratio on the percent carbon residue reduction at different extraction temperatures for extraction by n-hexane. fig. 13 effects of solvent to used oil ratio on the percent ash content reduction at different extraction temperatures for extraction by n-hexane. fig. 14 effects of solvent to used oil ratio on the viscosity index at different extraction temperatures for extraction by n-hexane. conclusions the following conclusions were obtained: 1n-butanol, which are liquid at normal conditions; gave oil recovery (93.7%), solvent recovery (95%), carbon residue reduction (88.6%), ash content reduction (75.9%) and viscosity index (100.6), at (40° c) and (5:1 vol./vol.) solvent to used oil ratio. 2nhexane, which are liquid at normal conditions; gave oil recovery (89%), solvent recovery (94.7%), carbon residue reduction (60.2%), ash content reduction (76.5%) and viscosity index (100.3), at (50° c) and (6:1 vol./vol.) solvent to used oil ratio. 3vacuum distillation was uneconomical to be operated industrially. but, it gave good color (deep yellow), carbon residue reduction (87%) and ash content reduction (74.8%), at (5 mbar), which was best operating. references 1-juma n. h., (2000), "lubricating oils and additives", middle refineries co., s. co., ministry of oil, december, p.10-32. 2-dturnell, (2006), "used oil re-refining study to address energy policy act of 2005 section 1838", office of oil and natural gas office of fossil energy u.s. department of energy, ch. 4, ch. 9. 3-u. s. patent no. 6117309, alexander d. b., martin macdonald and thomas g. murray, (2000). 4-whisman m. l., reynold j. w., goetzinger j. e. and cotton f. o., (1978), "re-refining makes quality oils", hydrocarbon processing, oct., pp 141. http://www.patentstorm.us/inventors/alexander_d__b__daspit-1632269.html http://www.patentstorm.us/inventors/alexander_d__b__daspit-1632269.html http://www.patentstorm.us/inventors/alexander_d__b__daspit-1632269.html http://www.patentstorm.us/inventors/martin_macdonald-1632270.html http://www.patentstorm.us/inventors/thomas_g__murray-1632272.html http://www.patentstorm.us/inventors/thomas_g__murray-1632272.html http://www.patentstorm.us/inventors/thomas_g__murray-1632272.html iraqi journal of chemical and petroleum engineering vol.15 no.4 (december 2014) 44-66 issn: 1997-4884 coagulation/ flocculation, microfiltration and nanofiltration for water treatment of main outfall drain for injection in nasiriyah oil field ahmed faiq al-alawy 1 and jaafar jabbar madlool 2 1 university of baghdad – chemical engineering department 2 university of baghdad – chemical engineering department abstract the present work aims to study the efficiency of coagulation/ flocculation as 1 st stage, natural gravity water filter or microfiltration (mf) as 2 nd stage and nanofiltration (nf) technology as final stage for treatment of water of main outfall drain (mod) for injection in nasiriyah oil field. effects of operating parameters such as coagulant dosage, speed and time of slow mixing step and settling time in the 1st stage were studied. also feed turbidity and total suspended solids (tss) in the 2 nd stage were studied. also feed concentration, temperature and operating time, in the final stage were studied. the results showed that the optimum dosage for alum was 35, 40 and 50 ppm. while, for ferric chloride it was 15, 20 and 30 ppm and for polyelectrolyte 4, 8 and 10 ppm for 11.8, 30 and 100 ntu initial turbidity respectively. the optimum speed for the 2 nd step was 25 rpm for each of alum 35 ppm, ferric chloride 15 ppm and polyelectrolyte 4 ppm. while the optimum time for the 2 nd step was 30 min for each of alum 35 ppm, ferric chloride 15 ppm and polyelectrolyte 4 ppm and settling time was 30 min for each of alum 35 ppm, ferric chloride 15 ppm and polyelectrolyte 4 ppm. it was found that turbidity and tss increases by increasing the inlet turbidity and tss. also it was found that salts concentration in product increases by increasing feed concentration and temperature. rejection percentages were (94.475 – 95.631 %), (88.088 – 90.714 %), (83.33 – 93.2 %), (85.116 – 92.727 %) and (65.385 – 72.727 %) for sulphate, total hardness (th), ca 2+ , mg 2+ and cl respectively and recovery percentage of product water was (11.429 – 38.143 %) for polyamide membrane (tfc). in the case of concentrate recirculation, feed concentration, permeate concentration and volume of permeate increases with increasing in operating time and 12.69 liter of water valid for injection in oil field was recovered from 25 liter feed after 180 minute. introduction water injection is used in the petroleum industry to enhanced oil recovery (eor) by maintaining the reservoir pressure and to sweep oil towards the production wells [1]. although the suspended solids must be reduced in the injection water to ensure no blockage of the reservoir rock, the sulphate must be removed from it because barium and strontium in the formation water will react with the injected water sulphate ions causing a supersaturated barium and/ or iraqi journal of chemical and petroleum engineering university of baghdad college of engineering coagulation/ flocculation, microfiltration and nanofiltration for water treatment of main outfall drain for injection in nasiriyah oil field 48 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net strontium sulphate scale formation in the production tubing and/or plugging of reservoir rock around the production well. the industry recognized solution is to remove sulphate from water before injection. this also helps prevent well souring by controlling sulphate reducing bacteria where there is simply a reduced source of sulphur that can be converted to hydrogen sulfide by thermophilic sulphate reducing bacteria. consequently, well souring does not occur [2-4]. water consumption has become an increasingly important factor in conventional and unconventional crude oil production. the petroleum industry has begun to emphasize water management practices and look for alternative water sources to reduce freshwater consumption, particularly in regions where water resources are scarce. saline water, brackish water, and even desalinated seawater are being used for oil exploration & production (e&p) [5]. the choice of which treatment to use from the great variety of available processes depends on the characteristics of the water, the types of water quality problems likely to be present, and the costs of different treatments [6]. coagulation is a process used to neutralize charges and form a gelatinous mass to trap (or bridge) particles thus forming a mass large enough to settle or be trapped in the filter. coagulation comes from the latin word (coagulare) which means to agglomerate. coagulation is the step where colloidal particles (similar to spheres of a diameter of less than 1 micrometer) are destabilized [7]. flocculation is the step where destabilized colloidal particles (or the particles formed during the coagulation step) are assembled into aggregates. flocculation is gentle stirring or agitation to encourage the particles thus formed to agglomerate into masses large enough to settle or be filtered from solution [8]. during the coagulation, when adding the coagulant (alum and ferric chloride) to water occur the following reactions [9]: al2(so4)3.18h2o + 6h2o → 2al(oh)3 +6h + +3so4 2+18h2o … (1) fecl3.18h2o + 3h2o → fe(oh)3 +3h + +3cl … (2) al2(so4)3.18h2o + 3ca(hco3)2 → 2al(oh)3+3caso4+6co2+18h2o … (3) 2fecl3 + 3ca(hco3)2 → 2fe(oh)3 + 3cacl+6co2 … (4) natural gravity water filter is multimedia filters, in which water flows by gravity through a porous bed of multi layers of granular media. the top layer is anthracite coal, and the bottom layer is sand. filters are operated until one of two criteria is exceeded the effluent turbidity standard or the allowable head loss through the filter. the filter is cleaned by backwashing to remove the particles that have been collected on the filter media [10 11]. either natural gravity water filter or mf membrane can be used in through the treatment operation. microfiltration (mf) is the process of removing particles or biological entities in the 0.025 μm to 10 μm range from fluids by passage through a micro porous medium such as a membrane filter [12]. nanofiltration (nf) has always been a difficult process to define and to describe. frequently nf and reverse osmosis (ro) are considered as one process, because of similarities of the basic principles used. the history of nf technology began in the 1970s when efforts started to develop ro membranes with reasonable water flux at relatively low pressures. the high pressures used in ro resulted in ahmed faiq al-alawy and jaafar jabbar madlool -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 49 considerable energy cost but the quality of permeate was very good, and often too good. thus a search for membranes with lower rejections of dissolved components but with higher permeability encouraged the development of nf membranes [1213]. nf is a membrane separation process which uses thin porous membranes with pore sizes between 0.5 and 2 μm. nf processes typically operate at pressures from 0.3 to 1.4 mpa. nf thus represents a process that functions between ultrafiltration (uf) and ro, and is often termed ‘loose reverse osmosis’ [14-15]. theoretical aspect water and solute fluxes the water and salt fluxes through nf membrane can be described by two models: solution-diffusion model and irreversible thermodynamics models. the two models are selected based on the credibility they have among the researchers as well their domination in practical applications. the two models are conceptually different. the expressions for water and salt (solute) fluxes through the membrane are given by the following equations [16]:   paj pw … (5) c k d j s         … (6) where jw is the product water flux, ap is the pure water permeation, δp is the operating pressure, δπ is the difference in the osmotic pressure across the membrane, js is the flux of salt permeating the membrane, (d/kδ) is the salt permeability coefficient, and δc is the difference in salt concentration across the membrane. the salt permeability coefficient takes into account the diffusivity coefficient of the salt through the membrane, d, the partitioning of salt concentration between the bulk solution and the membrane, k, and the membrane thickness, δ. the model considers (d/kδ) as an intrinsic parameter, which is not calculated by dividing the diffusivity coefficient to the product of the partitioning coefficient times the membrane thickness [17 – 18]. recovery the recovery is the percentage of the feed flow that passes through the membrane and becomes the permeate stream. it is an estimation of the performance of a membrane system. it measures the volumetric fraction of permeate to the feed showing how much of permeate is recovered from the feed. it is also called separation efficiency. %100 f p w q q r … (7) where rw is the recovery percentage, qp is the permeate (or product) flow rate and qf is the feed flow rate [13 – 19]. salt rejection percentage membrane salt rejection is a measure of overall membrane system performance, and membrane manufacturers typically state a specific salt rejection for each commercial membrane available. salt rejection through an nf membrane (cross flow operation) is nominally given by: %1001           feed permeate s c c r … (8) where rs is the rejection percentage, cfeed is the concentration of a specific component in the feed solution to the membrane process and cpermeate is the concentration of the same specific component in the cleaned discharge stream leaving the membrane system. ro membranes achieve nacl rejections of 98 – 99.8 %, while nf membranes exhibit rejection values greater than 90 % for multivalent ions and between 60 and 70 % for coagulation/ flocculation, microfiltration and nanofiltration for water treatment of main outfall drain for injection in nasiriyah oil field 50 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net monovalent ions. nf salt rejection, particularly for monovalent ions, is highly dependent on the total dissolved solid (tds) concentration and the presence of other ions [18]. concentration factor: the concentration factor (cf) is the ratio of the concentrate tds concentration in the concentrate or reject stream to its concentration in the feed stream [20]: feed econcentrat c c cf  … (9) experimental main outfall drain (mod) main outfall drain is a drainage channel, conveying to the shatt al arab the drainage water (soil wash water) of most of the irrigation projects in the medium reaches of the tigris and euphrates rivers. at present, the mod carries large amount of water with relatively low levels of nutrients, pesticides and other chemical components and with a moderate concentration of dissolved salt that must be treated anyway prior to any possible reutilization. the mod could be therefore a very interesting water resource that, if coupled with proper treatment facilities, could provide water for industrial (including oil fields), domestic, agriculture and environment (marshland) uses. table 1 shows the specification of water from mod. in this research, main outfall drain water treatment will be in three stages: coagulation and flocculation process, natural gravity water filter or microfiltration (mf) membrane, and nanofiltration process. coagulation and flocculation in coagulation and flocculation process using three initial turbidity contents is 11.8, 30 and 100 ntu. the first sets of tests were to find the efficiency of turbidity removal using alum, ferric chloride and polyelectrolyte as individual coagulants. the second set of expermints was to test speed and time of slow mixing and settling time with the above coagulants for the removal of turbidity. the jar test apparatus was performed as rapid mixing at 100 rpm for 2 min. during experiments, samples were withdrawn from the supernatant of each beaker for turbidity measurement. turbidity was measured by using the hach (2100 n) turbidimeter. natural gravity water filter and microfiltration (mf) membrane the water produce from coagulation and flocculation process was fed into natural gravity water filter 5 μm mf membrane and 1 μm mf membrane severally then the turbidity and tss of outlet was measured. the natural gravity water filter consisted of five layers with the following specifications from top to bottom as shown in figure 1. first layer consists of activated carbon and its shape is an upside down cone lump head and has circular two bases areas, while the other layers were similar in shape which was cylinder, but they have different contents. second layer consists of tourmaline stones, third layer consists of calcium stones, fourth layer consists of activated carbon, and fifeth layer consists of sand. mf membrane is polypropylene cartridge type which has an exceptionally good chemical compatibility and excellent resistance to micro-organism. nanofiltration (nf) membrane an experimental rig of nanofiltration membrane (axeon nf4-1812) was constructed in the laboratory as shown in figure 2. feed solution was prepared in a 25-liter vessel and then the outlet valve of the feed vessel was opened to let the solutions fill the entire pipes of the system. the feed ahmed faiq al-alawy and jaafar jabbar madlool -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 51 water was drawn from the vessel by means of a centrifugal pump to pass through microfiltration membrane, and then the water introduced into the nf elements by means of a high-pressure pump. through nf element, water transports from the inlet stream across the salt rejecting membrane and into the product stream. in some experiments, the rejected stream is recycled to the feed vessel and the reading was recorded for known periods of time. the gravimetric method is used to determine the sulphate ions in the feed permeate and reject streams while the titration was used to determine the total hardness, calcium, magnesium and chloride ions in the feed permeate and reject streams [21 – 23]. table 1: specification of mod water test range value test range value test range value ph 7.9 – 8.69 ca 2+ 240 – 500 mg/l cod 12 mg/l temp. 15.1 – 33.7 o c mg 2+ 290 – 430 mg/l bod 2.4 mg/l tss 6343 mg/l o & g 31.5 mg/l do 7 mg/l tds 5310 – 9630 mg/l no3 1.6 – 0.86 mg/l po4 0.02 – 0.29 mg/l cl 1400 – 2343 mg/l alk 180 – 296 mg/l na + 1367 mg/l so4 2 631 – 1796 mg/l acid nil k + 8.8 mg/l cond. 7930 – 12150 µs/cm turbidity 0.45 – 101 ntu ba 0.138 mg/l th 1920 – 3400 mg/l nacl % 16.622 % sr 0.0916 mg/l fig. 1: schematic diagram represents layers of natural gravity water filter coagulation/ flocculation, microfiltration and nanofiltration for water treatment of main outfall drain for injection in nasiriyah oil field 52 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net fig. 2: schematic diagram of nanofiltration (nf) separation process results and discussion coagulation and flocculation effect of coagulant dosage on turbidity removal the effect of different coagulants dosages (alum, fecl3 and polyelectrolyte) on turbidity removal from water of mod is shown in figures 3, 4 and 5 for initial turbidities of 11.8, 30 and 100 ntu respectively. these figures show that the optimum dose for alum was 35, 40 and 50 ppm for 11.8, 30 and 100 ntu initial turbidity respectively. while, for ferric chloride it was 15, 20 and 30 ppm and for polyelectrolyte 4, 8 and 10 ppm for 11.8, 30 and 100 ntu initial turbidity respectively. similar observation was noticed by hasan et al., and kadhum et al., [24 – 25]. colloidal particles in nature normally carry charges on their surface, which lead to the stabilization of the suspension. by addition of some chemicals dose, the surface property of such colloidal particles can be neutralized and precipitated so as the turbidity can be decreased until the colloidal particles are neutralized and precipitated where the minimum turbidity can be obtained. any more addition of the chemicals dose leads to increase the turbidity because there were no charged colloidal particles to be neutralized. these excess amounts of chemicals remain in the water as suspension and increase turbidity. effect of agitation speed and contact time on turbidity removal figures 6, 7 and 8 show the effect of the agitation speed of 2 nd step (flocculation step), time of 2 nd step and settling time on turbidity removal respectively for the same initial turbidity concentration (11.8 ntu) of water from mod. in these experiments, the optimum speed of 2 nd step was (25 rpm) for both of alum (35 ppm), ferric chloride (15 ppm) and polyelectrolyte (4 ppm). while the optimum time of 2 nd step was (30 min) for both of alum (35 ppm), ferric chloride (15 ppm) and polyelectrolyte (4 ppm) and of settling was (30 min) for both of alum (35 ppm), ferric chloride (15 ppm) and polyelectrolyte (4 ppm). a similar observation was noticed in the experimental study of james [26]. it has been found that for high solids concentrations and relatively low doses, flocculation occurs rapidly, but the flocs are not stable and can be broken at moderate stirring rates so high values of turbidity are obtained. increased mixing speed of 2 nd step heater thermometer raw water feed 5 μm mf 1 μm mf high pressure pump permeate pump recycle stream reject flow control reject rotameter pressure gauge nf membrane valve ahmed faiq al-alawy and jaafar jabbar madlool -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 53 leads to low values of turbidity. increased agitation more leads to the production of smaller flocs and the turbidity increased. by reducing the rate of stirring shortly after dosing, floc size (and settling rate) can be held at plateau levels, without subsequent decline. incomplete mixing of the flocculant may result in local overdosing and restabilization of a small number of particles, giving rise to a persistent haze in the water so high values of turbidity are obtained. increased mixing time of 2 nd step decreases values of turbidity. by continuity, the restabilization state appears for small number of particles and the turbidity increased. decreases settling time, allowing much higher flow rates to be treated. the electrostatic repulsive forces do not constrain the particles from approaching each other because the suspension is characterized as instable; therefore, short time period was required for settling. after this time there is no change in turbidity recorded. fig. 3: effect of coagulant dosage on turbidity removal (coagulation time 2 min (100 rpm), flocculation time 30 min (25 rpm), settling time 30 min, initial turbidity = 11.8 ntu, ph = 8.2) fig. 4: effect of coagulants dosage on turbidity removal (coagulation time 2 min (100 rpm), flocculation time 30 min (25 rpm), settling time 30 min, initial turbidity = 30 ntu, ph = 8.2) 0 1 2 3 4 5 6 7 8 9 0 10 20 30 40 50 60 t u r b id it y , n t u coagulant dosage, ppm polyelectrolyte alum ferric chloride 0 2 4 6 8 10 0 10 20 30 40 50 60 t u r b id it y , n t u coagulants dosage, ppm polyelectrolyte alum ferric chloride coagulation/ flocculation, microfiltration and nanofiltration for water treatment of main outfall drain for injection in nasiriyah oil field 54 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net fig. 5: effect of coagulants dosage on turbidity removal (coagulation time 2 min (100 rpm), flocculation time 30 min (25 rpm), settling time 30 min, initial turbidity = 100 ntu, ph = 8.2) fig. 6: effect of speed of 2 nd step on turbidity (coagulation time 2min (100 rpm), flocculation time 30 min, settling time 30 min, initial turbidity = 11.8 ntu, ph = 8.2) 0 2 4 6 8 10 0 10 20 30 40 50 60 t u r b id it y , n t u coagulants dosage, ppm polyelectrolyte alum ferric chloride 0 1 2 3 4 15 20 25 30 35 40 45 t u r b id it y , n t u speed of 2nd step, rpm polyelectrolyte (4ppm) alum (35ppm) ferric chloride (15ppm) 0 1 2 3 4 5 15 20 25 30 35 40 45 t u r b id ty , n t u time of 2nd step, min polyelectrolyte (4 ppm) alum (35 ppm) ferric chloride (15 ppm) ahmed faiq al-alawy and jaafar jabbar madlool -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 55 fig. 7: effect of time of 2 nd step on turbidity (coagulation time 2min (100 rpm), flocculation speed 25 rpm, settling time 30 min, initial turbidity = 11.8 ntu, ph = 8.2) fig. 8: effect of settling time on turbidity (coagulation time 2 min (100 rpm), flocculation time 30 min (25 rpm), initial turbidity = 11.8 ntu, ph = 8.2) natural gravity water filter and microfiltration membranes either natural gravity water filter or microfiltration (mf) membranes (5 & 1 μm) was used to remove the turbidity and tss from water. the same feed water inlet into sand filter and mf membranes (5 & 1 μm) and the results was arranged progressively as the following: natural gravity water filter → 5 μm mf → 1 μm mf. when the pore size of membrane was small, the quality of the production was better and the operating pressure was high, see figures 9 and 10. fig. 9: effect of feed turbidity change on product turbidity 0 2 4 6 8 0 10 20 30 40 50 60 t u r b id it y , n t u settling time, min polyelectrolyte (4 ppm) alum (35 ppm) ferric chloride (15 ppm) 0 15 30 45 60 0 20 40 60 80 100 120 o u tl e t t u r b id it y , n t u inlet turbidity, ntu sand filter 5 μm mf 1 μm mf coagulation/ flocculation, microfiltration and nanofiltration for water treatment of main outfall drain for injection in nasiriyah oil field 56 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net fig. 10: effect of feed total suspended solids (tss) change on product tss nanofiltration membrane effect of feed solute concentration by increasing concentration of solute feed from mod, osmotic pressure increases, then driving force (δp – δπ) decreases. this appears as a decrease of water flow through the membrane to 4.8 l/h at feed concentration 9630 mg/l. this is shown in figure 11. also, figure 11 show the effect of feed concentration of water from mod on recovery where upper value of recovery percentage was 38.143 % at feed concentration 1800 mg/l and by increasing the concentration of water feed from mod, the recovery percentage decrease until reaching to lower value 11.429 % at feed concentration 9630 mg/l according to equation 7. by increasing feed concentration from mod, solute flux increases according to the equation 6, this appears as an increase of solute concentration in the product as shown in figures 12 and 13. fig. 11: effect of feed concentration change on permeate rate and recovery percentage (at t = 25 o c, p = 85 psi, ph = 8, qf = 42 l/h) 0 300 600 900 1200 1500 1800 50 100 150 200 250 300 350 400 o u tl e t t s s , p p m inlet tss, ppm sand filter 5 μm mf 1 μm mf 8 16 24 32 40 48 4 8 12 16 20 24 0 2000 4000 6000 8000 10000 12000 r w % q p , l /h cf, mg/l permeate rate recovery% ahmed faiq al-alawy and jaafar jabbar madlool -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 57 fig. 12: effect of feed concentration on permeate concentration and rejection percentage (at t = 27 o c, p = 85 psi, ph = 8, qf = 42 l/h) fig. 13: effect of feed concentration on reject concentration and concentration factor (at t = 27 o c, p = 85 psi, ph = 8, qf = 42 l/h) figures 14, 16, 18, 20, and 22 show that increasing in feed concentration from mod leads to increase sulphate ion concentration (so4 2) (14.85 – 49.38 mg/l), th (65 – 405 mg/l), ca 2+ (10 – 34 mg/l), mg 2+ (8 – 64 mg/l), and cl (159.75 – 639 mg/l) in the permeate respectively because by increasing the feed, solute flux increases according to equation 6, this appears as an increase of solute concentration in the permeate. therefore, using nanofiltration membranes to remove ions (especially sulphate) and produce water within the allowable limits of ions in order to be injected into the oil field. also these figures show the change in rejection percentage. the salts which have high molecular weight such as so4 2 and ca 2+ pass through the membrane with rejection percentage higher than salts which have low molecular weight such as mg 2+ for the same values of valence. for different values of valence, the salts which have high valence such as ca 2+ pass through the membrane with rejection percentage larger than salts which have low valence such as cl for the same or approaching molecular weights. this relation was contingent with equation 10. figures 15, 17, 19, 21, and 23 show that the increasing in feed concentration of water from mod leads to increase sulphate ion concentration (so4 -2 ) (518.468 – 1011.757 mg/l), th (1775 – 5000 mg/l), ca +2 (190 – 730 mg/l), mg +2 (260 – 635 mg/l), and cl (887.5 – 69 72 75 78 81 84 0 1000 2000 3000 4000 5000 0 2000 4000 6000 8000 10000 r s% c p , m g /l cf, mg/l permeate conc. rejection% 1 1.3 1.6 1.9 2.2 2.5 2.8 3000 6000 9000 12000 15000 18000 0 2000 4000 6000 8000 10000 c f c r , m g /l cf, mg/l reject conc. conc. factor coagulation/ flocculation, microfiltration and nanofiltration for water treatment of main outfall drain for injection in nasiriyah oil field 58 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net 2786.75 mg/l) in the reject respectively because pure water transfer from feed side to the permeate side across the membrane and this leads to concentrate of solute in the reject. by increasing solute concentration for sulphate, th and mg 2+ in the feed, their solute fluxes increase. this caused much increase in the permeate concentration for these ions. then their values of cpermeate/cfeed increase and their rejection percentages decrease according to equation 8 see figures 16, 18 and 22. figures 20 and 24 show different effect for ca 2+ and cl because the increasing of solute flux leads a little increase the permeate concentration for these ions. then their values of cpermeate/cfeed decrease and their rejection percentages increase according to equation 8. fig. 14: effect of sulfate feed concentration on sulfate permeate concentration and sulphate rejection percentage (at t = 27 o c, p = 85 psi, ph = 8, qf = 42 l/h fig. 15: effect of sulfate feed concentration on sulfate reject concentration and sulphate concentration factor (at t = 27 o c, p = 85, ph = 8, qf = 42 l/h) 94.3 94.7 95.1 95.5 95.9 96.3 96.7 0 20 40 60 80 200 400 600 800 1000 r s s o 4 % c p e rm e a te s o 4 , m g /l cfeed so4, mg/l sulphate permeate conc. sulphate rejection % 1 1.2 1.4 1.6 1.8 400 600 800 1000 1200 1400 200 350 500 650 800 950 c f s o 4 c r e je ct s o 4 , m g /l cfeed so4, mg/l sulphate reject conc. sulphate conc. factor ahmed faiq al-alawy and jaafar jabbar madlool -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 59 fig. 16: effect of total hardness feed concentration on total hardness permeate concentration and total hardness rejection percentage (at t = 27 o c, p = 85 psi, ph = 8, qf = 42 l/h) fig. 17: effect of total hardness feed concentration on total hardness reject concentration and total hardness concentration factor, (at t = 27 o c, p = 85 psi, ph = 8, q f = 42 l/h) fig. 18: effect of calcium feed concentration on calcium permeate concentration and calcium rejection percentage (at t = 27 o c, p = 85 psi, ph = 8, q f = 42 l/h) 88 89 90 91 92 93 94 50 150 250 350 450 550 650 500 1000 1500 2000 2500 3000 3500 r s t h % c p e rm e a te t h , m g /l cfeed th, mg/l th permeate conc. th rejection % 1.3 1.9 2.5 3.1 3.7 1500 3500 5500 7500 500 1000 1500 2000 2500 3000 3500 c f t h c r e je ct t h , m g /l cfeed th, mg/l th reject conc. th conc. factor 75 80 85 90 95 100 105 5 10 15 20 25 30 35 40 0 100 200 300 400 500 600 r s c a % c p e rm e a te c a , m g /l cfeed ca, mg/l ca permeate conc. ca rejection % coagulation/ flocculation, microfiltration and nanofiltration for water treatment of main outfall drain for injection in nasiriyah oil field 60 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net fig. 19: effect of calcium feed concentration on calcium reject concentration and calcium concentration factor (at t = 27 o c, p = 85 psi, ph = 8, q f = 42 l/h) fig. 20: effect of magnesium feed concentration on magnesium permeate concentration and magnesium rejection percentage (at t = 27 o c, p = 85 psi, ph = 8, q f = 42 l/h) fig. 21: effect of magnesium feed concentration on magnesium reject concentration and magnesium concentration factor (at t = 27 o c, p = 85 psi, ph = 8, q f = 42 l/h) 1.4 1.7 2 2.3 2.6 100 300 500 700 900 1100 0 100 200 300 400 500 600 c f c a c r e je ct c a , m g /l cfeed ca, mg/l ca reject conc. ca conc. factor 84 88 92 96 100 0 20 40 60 80 100 150 200 250 300 350 400 450 r s m g % c r e je ct m g , m g /l cfeed mg , mg/l mg permeate conc. mg rejection % 1.2 1.5 1.8 2.1 2.4 2.7 3 200 300 400 500 600 700 800 100 150 200 250 300 350 400 450 c f m g c r e je c t m g , m g /l cfeed mg, mg/l mg reject conc. mg conc. factor ahmed faiq al-alawy and jaafar jabbar madlool -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 61 fig. 22: effect of chloride feed concentration on chloride permeate concentration and chloride rejection percentage (at t = 27 o c, p = 85 psi, ph = 8, q f = 42 l/h) fig. 23: effect of chloride feed concentration on chloride reject concentration chloride concentration factor (at t = 27 o c, p = 85 psi, ph = 8, q f = 42 l/h) effect of operating temperature increasing of inlet operating temperature within the range of 20 – 37 o c will increase the product rate to the range of 12.72 – 18.6 l/h and recovery percentage of water of range 30.286 – 44.286 %. this is shown in figure 24. a change in operating temperature of feed water from mod changes (1) the densities and viscosities of the feed, and (2) the osmotic pressure of the system. an increase of temperature increases the osmotic pressure of feed water from mod, resulting in a decrease in the driving force (∆p – ∆π). thus while change (1) above increase the relative flow of the pure water through the membrane with increase in temperature; the change in the osmotic pressure has the opposite effect. a similar observation was noticed in the experimented study of mohammed and mattheus [20, 27]. the increase of operating temperature for feed water from mod within the range of 20 – 37 o c leads to increase the flux; this appears as an increase of salts concentrations in the product to the range of 580 – 840 mg/l. the effect of operating temperature on salts concentrations, can be explain the decreasing of rejection percentage with increase in 64 66 68 70 72 74 76 78 0 200 400 600 800 1000 400 700 1000 1300 1600 1900 2200 2500 r sc l c p e rm e a te c l, m g /l cfeed cl, mg/l cl permeate conc. cl rejection % 0.6 1 1.4 1.8 2.2 2.6 500 1500 2500 3500 4500 200 600 1000 1400 1800 2200 2600 c f c l c r e je ct c l, m g /l cfeed cl, mg/l cl reject conc. cl conc. factor coagulation/ flocculation, microfiltration and nanofiltration for water treatment of main outfall drain for injection in nasiriyah oil field 62 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net operating temperature, see figure 25. while figure 26 show that the reject concentration and concentration factor increases with the ranges of (6280 – 6630 mg/l) and (1.794 – 1.894) respectively with increasing temperature because the increasing of pure water passed through the membrane leads to increase the salts concentration in the reject. a similar observation was noticed in the experimented study of mohammed [20]. recirculation of concentrate in the nanofiltration (nf) membrane technology experiment with recirculation mode, the permeate was removed and the concentrate stream was recycled back to the feed vessel in order to recover high quantity from pure water. the operating time taken to 180 min, in this time the difference between operating pressure and osmotic pressure became very small then the process is stopped. at time equal to zero, for recirculation of concentrate the operating conditions for the water from mod with 8390 mg/l concentration were vf = 25 l, qf = 50 l/h, t = 27 o c, p = 185 psi. figure 27 shows the effect of time on volume of permeate and recovery percentage. as the time increased the product rate decreased. this leads to decrease the recovery percentage according to the equation 7. due to the increase of the feed concentration with time in the recirculation mode, the salts concentration in the product increased with the increase in operating time. this means that the rejection percentage decrease, see figure 28. fig. 24: effect of operating temperature on product rate flux and recovery (at c f = 3500 ppm, p = 85 psi, ph = 8, q f = 42 l/h) 30 34 38 42 46 50 54 12 14 16 18 20 22 24 15 20 25 30 35 40 r w % q p , l/ h t, oc product rate flux recovery% ahmed faiq al-alawy and jaafar jabbar madlool -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 63 fig. 25: effect of operating temperature on product solute concentration and rejection percentage, (at c f = 3500 ppm, p = 85 psi, ph = 8, q f = 42 l/h) fig. 26: effect of operating temperature on reject concentration and concentration factor (at cf = 3500 ppm, p = 85 psi, ph = 8, q f = 42 l/h) fig. 27: effect of operating time on volume of permeate and recovery percentage (recirculation of concentrate, v f = 25 l, q p = 42 l/h, t = 27 o c, ph = 8 and p = 185 psi) 74 77 80 83 86 89 92 500 600 700 800 900 1000 1100 15 20 25 30 35 40 45 r % c p , m g /l t, oc product conc. rejection% 1.76 1.8 1.84 1.88 1.92 6200 6300 6400 6500 6600 6700 15 20 25 30 35 40 c f c r , m g /l t, oc reject conc. conc. factor 0 8 16 24 0 8 16 24 0 50 100 150 200 r w % v p , l t, min volume of permeate recovery % coagulation/ flocculation, microfiltration and nanofiltration for water treatment of main outfall drain for injection in nasiriyah oil field 64 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net fig. 28: effect of operating time on permeate concentration and rejection percentage (recirculation of concentrate, v f = 25 l, q p = 42 l/h, t = 27 o c, ph = 8 and p = 185 psi) conclusion produced water appropriate for injection in the oil field from mod, using conventional methods and nanofiltration membranes. in coagulation/ flocculation process, optimum dosage for alum was 35, 40 and 50 ppm for 11.8, 30 and 100 ntu initial turbidity respectively. while, for ferric chloride it was 15, 20 and 30 ppm and for polyelectrolyte 4, 8 and 10 ppm for 11.8, 30 and 100 ntu initial turbidity respectively. the optimum speed of 2nd step was 25 rpm. while the optimum time of 2nd step was 30 min and of settling was 30 min. for the same dosage, the ability of alum, ferric chloride and polyelectrolyte to remove the turbidity is arranged progressively as the following: polyelecrolyte → ferric chloride → alum. for the same feed, the ability of the filters to remove the turbidity and tss from water was arranged progressively as the following: natural gravity water filter → 5 μm mf → 1 μm mf. microfiltration can be used to reduce the turbidity, tss, and the particle size to the demand limits. nanofiltration membrane can be used to reduce the sulphate to the demand limits. the product rate of the membrane decreases with increasing feed concentration. the maximum recovery percentage (38.143 %) was at cf = 1800 mg/l for p = 85 psi, qf = 42 l/h, t = 25 o c and ph = 8. maximum component rejection percentage at p = 85 psi, qf = 42 l/h, t = 27 o c and ph = 8 95.631 %, 90.714 %, 93.2 %, 92.727 %, 72.727 % for sulphate, th, ca 2+ , mg 2+ and cl respectively. in recirculation of concentrate process, maximum value of volume of permeate is (12.69 liter) from feed vessel (25 liter) after 180 min. references 1goshtasp cheraghian, mahmood hemmati, mohsen masihi and saeed bazgir, 2013, “an experimental investigation of the enhanced oil recovery and improved performance of drilling fluids using titanium dioxide and fumed silica nanoparticles”, journal of nanostructure in chemistry (78), 1 – 9. 2ayad a. al-haleem a. al-razaq, 2012, “oilfield produced water management: treatment, reuse and 0 20 40 60 80 100 0 2000 4000 6000 8000 0 30 60 90 120 150 180 210 r s % c p , m g /l t, min permeate conc. rejection% ahmed faiq al-alawy and jaafar jabbar madlool -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 65 disposal”, j. baghdad for sci. (9), 124 – 132. 3vws oil & gas, 2011, “veolia – "vws oil & gas" capabilities in upstream oil & gas projects”. 4siemens as, oil and gas division, 2010, “water treatment for injection”, product bulletin no. 2. 5may wu, marianne mintz, michael wang, salil arora and chiu yiwen, 2011, “consumptive water use in the production of ethanol and petroleum gasoline – 2011 update”, technical report anl/esd/09-1-update, argonne national laboratory, lemont, illinois. 75p. 6mohammad a. m. al-tufaily and entesar k. h., 2010, “modeling of conventional water supply treatment plant”, iraqi journal of mechanical and material engineering, a special no. of second engineering conference of college of engineering, babylon university. 7snf floerger, 2003, “coagulation-flocculation”, france. 8rahul rahul, usha jha, gautam sen and sumit mishra, 2014, “carboxymethyl inulin: a novel flocculant for wastewater treatment”, international journal of biological macromolecules (63), 1 – 7. 9mrwa, 2003, “coagulation and flocculation process fundamentals”, mrwa: minnesota rural water association. 10mathilde j. hedegaard and hansjørgen albrechtsen, 2014, “microbial pesticide removal in rapid sand filters for drinking water treatment – potential and kinetics”, water research (48), 71 – 81. 11le anh tuan, 2008, “treatment of surface water and municipal wastewater by hybrid ceramic microfiltration systems”, m.sc. thesis, asian institute of technology. 12hjerpe kim and olsson jonathan, 2012, “analysis of membrane alternatives suitable for kvarnagården water treatment plant”, m.sc. thesis, chalmers university of technology. 13fernando m.a.b., 2009, “effect of sat pre-treatment on performance of nf membranes”, m.sc. thesis, the unesco-ihe institute for water education. 14richard w. baker, 2012, “membrane technology and applications”, john wiley & sons ltd, 3rd edition. 15yu miyashita, 2007, “removal of n-nitrosamines by nanofiltration and reverse osmosis membranes”, m.sc. thesis, georgia institute of technology. 16thor thorsen and harald fløgstad, 2006, “nanofiltration in drinking water treatment”, techneau, d5.3.4b. 17ahmed faiq al-alawy, 2007, “performance of manipulated direct osmosis in water desalination process”, ph.d. thesis, university of baghdad. 18rana raheem said, 2011, “forward osmosis process for the treatment of wastewater from textile industries”, m.sc. thesis, baghdad university. 19uche m. eboagwu, 2011, “evaluation of membrane treatment technology to optimize and reduce hypersalinity content of produced brine for reuse in unconventional gas wells”, m.sc. thesis, texas a&m university. 20mohammed b., 2008, “membrane separation process for treatment and reuse of water from effluents of cooling towers”, m.sc. thesis, university of baghdad. coagulation/ flocculation, microfiltration and nanofiltration for water treatment of main outfall drain for injection in nasiriyah oil field 66 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net 21david harvey, 2000, “modern analytical chemistry”, the mcgraw-hill companies, inc., 1st ed. 22jeffery g. h., bassett j., mendham j. and denney r.c., 1989, “vogel's textbook of quantitative chemical analysis”, john wiley & sons, inc., 5th ed. 23aparna g. sajjan, 2013, “lab manual of chemistry ii”. 24hasan f. m., ahmed f. a., nada n. a. and manal a. m., 2010, “using aluminum refuse as a coagulant in the coagulation and flocculation processes”, iraqi journal of chemical and petroleum engineering, university of baghdad (11), 15 – 22. 25kadhum m. shabe, suhama e. salah and mervit m. janbi, 2011, “coagulation-flocculation process to treat pulp and paper mill wastewater by fenugreek mucilage coupled with alum and polyaluminum chloride”, alkhwarizmi engineering journal, (7), 39 – 47. 26james m. ebeling, sarah r. ogden, philip l. sibrell and kata l. rishel, 2004, “application of chemical coagulation aids for the removal of suspended solids (tss) and phosphorus from the microscreen effluent discharge of an intensive recirculating aquaculture system”, north american journal of aquaculture (66), 198 – 207. 27mattheus f.a. goosen, shyam s. sablani, salha s. al-maskari, rashid h. al-belushi and mark wilf, 2002, “effect of feed temperature on permeate flux and mass transfer coefficient in spiralwound reverse osmosis systems”, desalination (144), 367 – 372. iraqi journal of chemical and petroleum engineering vol.16 no.1 (march 2015) 7990 issn: 1997-4884 extraction of aromatic hydrocarbons from lube oil using different co-solvent ibtehal k. shakir and muslim a. qasim chemical engineering department, college of engineering, baghdad university abstract an investigation was conducted effect of addition cosolvent on solvent extraction process for two types of a lubricating oil fraction (spindle) and (sae-30) obtained from vacuum distillation unit of lube oil plant of daura refinery. in this study two types of co-solvents ( formamide and n-methyl, 2, pyrrolidone) were blended with furfural to extract aromatic hydrocarbons which are the undesirable materials in raw lubricating oil, in order to improve the viscosity index, viscosity and yield of produced lubricating oil. the studied operating condition are extraction temperature range from 70 to 110 °c for formamide and 80 to 120 °c for n-methyl, 2, pyrrolidone, solvent to oil ratio range from 1:1 to 2:1 (wt./wt.) for furfural with formamide extraction and 1:1 to 3:1 (wt./wt.) for furfural with nmp extraction. the results of the investigation show that the viscosity index of lubricating oil fraction increases while viscosity and percentage yield of raffinate decreases with increasing extraction temperature, the solvent to oil ratio and co-solvent to furfural ratio. for formamide the best temperature were 90 °c, furfural to co-solvent ratio (60:40) and solvent to lube oil ratio (1.5:1) to get best value of viscosity index 102, viscosity 3.01 cst and 69.23 % yield. while for nmp co-solvent 110 °c extraction temperature, (2:1) solvent to lube oil ratio and (60:40) furfural to co-solvent ratio, to produce lube oil with 96 viscosity index, 9.10 cst viscosity and 68.50 yield. key words: co-solvent, extraction of aromatic, lubricating oil, viscosity index, viscosity, yield introduction refining of crude oil to produce lubricating oil is one of the oldest refinery arts. suitable crudes are fractional to isolate a suitable boiling range material, usually in the 316 to 593 °c range, to produce a distilled oil fraction. various solvent purification steps are then used to reject components not suitable for lubricating stock. aromatics are too unstable, and refiners resort to various means to remove aromatics from potential lube fraction. while many solvents were proposed for aromatics extraction, furfural has been a preferred solvent since about 1933 when the first commercial furfural extraction units were built. since the furfural unit is often a bottleneck in the lube refining process, improvement in the capacity of furfural without loss of selectivity would be of value to the lube refining industry [1]. iraqi journal of chemical and petroleum engineering university of baghdad college of engineering extraction of aromatic hydrocarbons from lube oil using different co-solvent 80 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net the most important properties of lubricating oil which solvent extraction is meant to improve are viscosity– temperature characteristics, stability toward oxidation, and carbon residue. the improvement of these properties is accomplished almost entirely by the extraction of aromatics [2]. since the feed stock contains aromatic material usually ranging from 30 wt. % to 60 wt. %, the feed stock is initially subjected to an extraction step. removal of aromatic material improves the viscosity index, color, and oxidation stability and inhibition response of the base oil [3]. a strong temptation to produce high viscosity index lubes has led to a prolific growth of solvent extraction. solvents widely used for this affair are furfural, phenol, mixture of cresols and propane. many other solvent’s like aniline, sulfur dioxide are enlisted; but without much use [4]. furfural is the most widely used solvent because its selectivity toward aromatic compounds is high enough [5]. solvent and lubricating oil are especially complex systems because of the high number of components in the system [6]. using a second solvent in liquid-liquid extraction is a common task in extraction. second solvent could increase the yield of extraction by forming extract-solvent complex [7]. specifications required achieved by niigata engineering co. are leading companies in iraq to produce lubricating bas oil from lube-oil cut in furfural extraction unit [8]. the most important specifications and operation condition worked out by this company are listed in table (1). table (1): important specifications and operation condition present from niigata engineering co. [8]. type stock stock 40 (spindle) stock 60 (sae-30) viscosity at 100 °c, cst 2.9-3.2 9.0-11.0 viscosity index 80°c 97-105 92-97 temperature (top) treating 90 121 yield vol. % 70 60 furfural:lube oil 1.8-2:1 2.2-2.5:1 the improvement in the properties of an oil gained by solvent refining is somewhat dependent on the properties of the original stock as well as the type of solvent employed, and since base oils differ widely in molecular composition and physical properties due to the crude source, hence each refinery must satisfy himself by laboratory tests and studying in detail the selected fraction of lubricating oil [9]. raman and devotta [3], in 2003, discovered an improved furfural extraction process for lube oil base stock containing aromatic type material by the addition of a co-solvent preferably an aliphatic amide or mixture of amides to furfural to facilitate phase separation, selectivity, and increase the raffinate yield while maintaining the same raffinate measured by raffinate refractive index. the results show that for extraction conducted at solvent to feed treat ratio of 1.5, the co-solvent –furfural blends are more effective than furfural alone, resulting in more than 3 vol % improvement in raffinate yield at same raffinate refractive index, and an increase of more than 5 vol. % of raffinate yield at same refractive index at solvent to feed treat ratio of 1.8. ibtehal k. shakir and muslim a. qasim -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 81 abdul-halim and amal [10], in 2008, improved the viscosity index of a lubricating oil fraction (sae – 30). by extracting the undesirable materials which reduce the viscosity index of raw lubricating oil fraction, the first solvent was furfural and the second was nmp (n-methyl, 2, pyrrolidone). where the extraction temperature was range from 70 to 110 °c for furfural and nmp, solvent to oil ratio range from 1:1 to 5:1 (wt. /wt.) for furfural and from 0.5:1 to 2:1 (wt. /wt.) for nmp. the results show that the viscosity index of lubricating oil fraction increases with increasing extraction temperature and increasing the solvent to oil ratio and reaches 83 for nmp extraction at extraction temperature 110 °c and solvent to oil ratio 2:1, while the viscosity index reaches to 80 for furfural extraction at the same extraction temperature and solvent oil ratio. higher viscosity index of lubricating oil fraction is obtained by using nmp instead of furfural under the same operating variables. hatampipour m. s. etal [11], in 2009, used 2, 2, 4-tri methyl pentane as co-solvent with furfural for extraction of aromatic hydrocarbons from lube oil cut. general binary interaction parameters are computed and reported for estimating the liquidliquid equilibrium products between 50 and 70 °c. also, a generalized model is presented for calculation of the refractive index and specific gravity of lube oil fraction. raman et al.[3], in 2010, suggested to use n-dimethyl amide as a cosolvent with nmp to increase extraction yield by more than 6 wt. % than raffinate obtained by using nmp alone. this co-solvent was selected from a group consisting of formamide, n-methyl formamide, acetamide, propionamide. alibrahemi and sharif [12], in 2010, study the extraction system under atmospheric pressure and different temperatures to improve the properties of lubricating oil produced from a vacuum distillation in the al_daura refinery, to increase the productivity of raffinate; the top product of extraction column, and to improve the process by using two different types of solvents (furfural and normal nmp). the best results achieved for specification and productivity blending (80% furfural with 20% nmp and up to 60% furfural with 40% nmp), where viscosity index increased to (114) and refractive index decreased with increasing production rate. the aim of this study is to improve the percent raffinate yield and viscosity index of different lubricating base oil stock 40 (spindle) and stock 60 (sae30) obtained from vacuum distillation unit of dura refinery by using a new solvent mixture (furfural + a cosolvent). the investigation includes also a detail study of the effect of extraction temperature and the type of co-solvent choosing from two cosolvent ( formamide and n-methyl, 2pyrrolidone) which was blended to furfural, solvent to co-solvent ratio, and mixed solvent to lube oil ratio on viscosity, viscosity index and the percentage yield of the produced lubricating oil. experimental feedstock two feed stocks were used in this work, the distillate lube oil fraction stock 40 (spindle) and stock 60 (sae30) obtained from vacuum distillation unit of lube oil plant of daura refinery. the feedstock for vacuum distillation unit was atmospheric residue produced from mixed iraqi crude oils (60 % of basrah, 30 % of kirkuk and 10 % of sharki extraction of aromatic hydrocarbons from lube oil using different co-solvent 82 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net baghdad).table (2) shows the determined properties of the lube oil fraction [9]. table (2), properties of lube oil distillation fraction no . specificati on feedstoc k 40 (spendil e) feedstoc k 60 (sae40) 1 specific gravity @ 60/60 o f 0.896 0.932 2 viscosity, cst, @ 40°c 21 151.48 3 viscosity, cst, @ 100°c 3.9 11.68 4 viscosity index 59 47 5 pour point, °c 22.3 38.34 6 coc flash point, °c 204.45 260 7 sulfur content, % wt. 1.95 2.76 8 color, astmd1500, at 25°c 2.5 4.5 solvents three solvents were used in this work. these solvents are furfural (liaosin private limited company, china), n-methyl-2-pyrrolidinone (fluka chemicals ag, germany) and formamide (exact chemical co., china) table (3) shows the determined properties of these solvent. table (3), properties of furfural, formamide and nmp furfural formamide nmp structure density ( 25 4 d ), g/cm 3 1.1563 1.134 1.0270 boiling point, °c 161 210 202 refractive index ( 25 d n ) 1.5235 1.447 1.4690 coc flash point, °c 68 175 95 melting point, °c -36.5 2.5 -24 extraction experiment laboratory batch extraction unit was used in the present work. fig.(1) shows the details of the laboratory extraction unit. this unit consists of a heat source stuart magnetic stirrer device, a bench scale 1-liter and a 250ml, of 2necks pyrex flask extraction apparatus. the middle flask neck was connected with thermometer and the second neck was connected with recycle condenser. the magnetic stirrer with 1.5"length magnetic stirrer bars was used to mix the feedstock with the extraction solvent inside the flash extractor. agitation speed and flask temperature were kept constant using regulator attached with electrical magnetic stirrer. the lube oil fraction was mixed with the extraction solvent in the extractor flask at controlled specified temperature. ibtehal k. shakir and muslim a. qasim -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 83 fig.1, laboratory extraction unit the operating condition of total solvent to feedstock ratio, treating temperature and solvent to co-solvent ratio were specified. mixing the three materials at the specified temperature was continued for the best period of 60 minutes then the mixture was left at the specified temperature for 60 minutes to be separated in to two phases by using a separating funnel. top of the liquid phases are light raffinate solution and the bottom liquid phase is heavier extract solution. the raffinate phase contained about (70-80) % of lube oil without aromatics substances and (3020) % solvent, the extract phase contained about (70-80) % 0f solvent with (30-20) % aromatics and naphthenic substances. the interface level formed after steady state to be constant. the two solutions were weighted to ensure material balance closure [9]. solvent recovery the solvent was recovery from the raffinate solution by distillation under vacuum about (0.1 bar) to reduce flash point of distillate, prevent furfural decomposition and avoid oxidation of furfural (because the furfural will be converting to coal at higher temperature when contact with air). the unit consists of a 250ml, tow neck pyrex flask, the middle flask neck was connected with thermometer (to indicate vapor temperature) and the second neck connected with condenser. at the end of condenser there is a receiver flask which connected with a trap and vacuum pump with a vacuum gage pressure. the raffinate solution was heated in the flask using heating mantle with a regulator to control heat supply. the stripped raffinate was weighted and the raffinate yield was obtained. result and discussion effect of extraction temperature and furfural to co-solvent (formamide) ratio for stock 40 (spindle) on raffinate viscosity fig. (2), shows the effect of the extraction temperature, and furfural to co-solvent (formamide) ratio on raffinate viscosity which calculated in extraction of aromatic hydrocarbons from lube oil using different co-solvent 84 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net laboratory at 100°c. the viscosity of raffinate product from solvent extraction process increase with decrease the extraction temperature or decreasing the solvent to lube oil ratio [6]. fig. 2, effect of extraction temperature on raffinate viscosity at various solvent to co-solvent ratio (at solvent to lube oil ratio 1:1) effect of extraction temperature and furfural to co-solvent (formamide) ratio for stock 40 (spindle) on raffinate viscosity index figures (3) to (5) show the effect of the extraction temperature and solvent (furfural) to co-solvent (formamide) ratio on raffinate viscosity index at various mixed-solvent( furfural and formamide) to lube oil ratio. by analyzing the graph, the increase in extraction temperature will increase the viscosity index in raffinate phase for 1:1 mixed-solvent to oil ratio at different furfural to co-solvent (formamide) ratio. fig. (3), clearly indicates that furfural to formamide ratio slightly effect on the viscosity index for raffinate produced from extraction compared with extraction temperature for a given solvent to oil ratio, due to that the power solvent and selectivity for formamide and furfural solvents were nearly identical. the increase of extraction temperature by 10 ° c will increase the viscosity index one point for a given solvent to lube oil ratio at the different ratio from furfural and formamide solvent. the increase in extraction temperature will increase the solubility of undesirable materials especially polycondensed aromatics in solvent, the aromatics materials which reduce the viscosity index of lubricating oil [13]. fig.3, effect of extraction temperature on raffinate viscosity index at various solvent to co-solvent ratio (at solvent to lube oil ratio 1:1) figures (4) and (5) indicate that the increase in solvent to lube oil ratio has a higher effect on increasing the viscosity index of lubricating oil fraction compared with extraction temperature and furfural to formamid ratio in extraction process. the increase of solvent to oil ratio (1.5:1) in fig. (5) will increase viscosity index above five points nearly for a given extraction temperature and furfural to formamid ratio as extraction solvents. 2.5 2.7 2.9 3.1 3.3 3.5 3.7 3.9 65 70 75 80 85 90 95100105110115120 v is co si ty a t 1 0 0 ° c , cs t temperatur, °c solvent to lube oil 1:1 furfural:formamide,(80: 20) furfural:formamide,(60: 40) furfural:formamide,(40: 60) 85 87 89 91 93 95 97 99 60 65 70 75 80 85 90 95100105110115120 v is co si ty n id e x temperatur, °c solvent to lube oil 1:1 furfural:formamide,(80: 20) furfural:formamide,(60: 40) furfural:formamide,(40: 60) ibtehal k. shakir and muslim a. qasim -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 85 while when increasing the extraction temperature above 100 °c the viscosity index has affixed value , due to that formamid solvent at high temperature will be has a low selectivity and high power solvent where it dissolves aromatic and paraffinic compound, together in extraction phase [14]. since poly-aromatics and hetero compounds are components with a low viscosity index, poor oxidation and color stability, their removal is required in solvent extraction. together with the poly-aromatics and the hetero compounds, most of the diaromatics are extracted with only a part of the mono-aromatics [13].the selectivity of furfural is very higher than other solvents at low temperature, while the solvent power to furfural increasing at high temperature. fig.4, effect of extraction temperature on raffinate viscosity index at various solvent to co-solvent ratio (at solvent to lube oil ratio 1.5:1) fig. 5, effect of extraction temperature on raffinate viscosity index at various solvent to co-solvent ratio (at solvent to lube oil ratio 2:1) effect of extraction temperature and furfural to co-solvent (formamide) ratio for stock 40 (spindle) on raffinate yield fig. (6) shows the effect of the extraction temperature, mixed-solvent (furfural and formamide) to lube oil ratio and solvent (furfural) to cosolvent (formamide) ratio on raffinate yield. by analyzing data in the graph, the furfural to formamide ratio slightly effected on the yield of raffinate produced from extraction compared with extraction temperature for a given solvent to oil ratio, due to the power solvent and selectivity for formamide and furfural solvents were the same specification also this feedstock of lube oil has few aromatic substance[1]. using a second solvent in liquid– liquid extraction is a common task in extraction. the co-solvent could increase the yield of extraction in two ways, first is acting in parallel with main solvent, when the second solvent is selective to extract and increases the 92 94 96 98 100 102 104 106 108 110 65 70 75 80 85 90 95100105110115120 v is co si ty in d e x temperatur, °c solvent to lube oil 1.5:1 furfur al:for mami de,(80 :20) 92 94 96 98 100 102 104 106 108 110 65 70 75 80 85 90 95100105110115120 v is co si ty i n d e x temperatur, °c solvent to lube oil 2:1 furfural:formamide,(80:20) furfural:formamide,(60:40) furfural:formamide,(40:60) furfural:formamide,(20:80) extraction of aromatic hydrocarbons from lube oil using different co-solvent 86 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net yield of extraction by forming extract– solvent complex. and the second is acting against main solvent when the second solvent is selective to raffinate. in this case second solvent increases the yield of extraction by forming raffinate–solvent complex, and the mixture reaches to equilibrium state in a shorter time. however, by use of the co-solvent the purity of extract may be increased. for this reason second solvent should have higher solubility in one of the extract or raffinate phases [5]. in this work formamide has a higher solubility in extract phase. fig.6 effect of extraction temperature on raffinate yield at various solvent to co-solvent ratio (at solvent to lube oil ratio 1:1) effect of extraction temperature and furfural to co-solvent (nmp) ratio for stock 60 (sea-30) on raffinate viscosity fig. (7) shows the effect of the extraction temperature, mixed-solvent (furfural and nmp) to lube oil ratio and solvent (furfural) to co-solvent (nmp) ratio on raffinate viscosity which calculated in laboratory at 100°c. the figure clearly indicated that the effect of the ratio of two solvents are higher than the effect of the extraction temperature on the viscosity of raffinate phase produced from solvent extraction for a given solvent to lube oil ratio. the gradual addition of co-solvent (nmp) decreases the amount of furfural for a given extraction temperature and solvent to lube oil ratio respectively which will have a higher effect in decreasing the raffinate viscosity, this caused by of the higher activity and solvent power of nmp in compare with furfural solvent[14]. the high molecular aromatics have the higher viscosity among the hydrocarbons in raw lubricating oils and the extraction of these materials decrease its content in the produced raffinate and increase the paraffin content which have a viscosity relatively lower than that of aromatics as mentioned by kosters [15]. in general, the extraction temperature is responsible upon the relation of immiscibility between solvent and lube base oil, and a significant impact to extraction process. its effect on selectivity of the solvent and solvent power, the solvent power increase with increase extraction temperature to become solvent and lube oil are mixing completely, while selectivity increase with decrease extraction temperature. the extraction temperature must install for each type of lubricating oil for any extraction process, so get the equilibrium between selectivity and power solvent to give best results qualitative and quantitative [16]. 65 67 69 71 73 75 77 79 81 83 85 6065707580859095100105110115120 y ie ld , w t% temperatur, °c solvent to lube oil 1:1 furfural:formamide,(8 0:20) furfural:formamide,(6 0:40) furfural:formamide,(4 0:60) ibtehal k. shakir and muslim a. qasim -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 87 fig. 7 effect of extraction temperature on raffinate viscosity at various solvent to co-solvent ratio (at solvent to lube oil ratio 1:1) effect of extraction temperature and furfural to co-solvent (nmp) ratio for stock 60 (sea-30) on raffinate viscosity index figures (8) to (10) show the effect of the extraction temperature and solvent furfural to co-solvent (nmp) ratio on raffinate viscosity index at various mixed-solvent ( furfural and nmp) to lube oil ratio. the increase in extraction temperature will encourage the solubility of undesirable materials such as aromatics and a small percentage of the paraffinic in extraction solvent. the graphic shows that the viscosity index increases with increase the extraction temperature. the increase of extraction temperature by 10 ° c will increase the viscosity index by approximately two points for a given solvent to lube oil ratio at the different ratio of furfural and nmp solvent. the increases of the co-solvent nmp to furfural ratio will increase the viscosity index by approximately two point for a given solvent to lube oil ratio at the different extraction temperature, this caused by the high power solvent and selectivity of the cosolvent nmp in compared with furfural. the higher solvent power of co-solvent compared with furfural gave higher viscosity index for the same operating variables. these results are in agreement with those obtained by sequeira and sherman [14] which is stated that the solvent power is better (solvent to oil ratio is lower) for nmp than for furfural. fig.8 effect of extraction temperature on raffinate viscosity index at various solvent to co-solvent ratio (at solvent to lube oil ratio 1:1) figures (9) and (10) show that the increase in solvent to lube oil ratio has a higher effect on increasing the viscosity index of lubricating oil fraction compared with extraction temperature and co-solvent to furfural ratio. in case of using furfural as extraction solvent in operating unit, the significant solvent to oil ratio should be higher than (1:1) ratio because of the constancy of the viscosity index on a fixed value using different extraction temperatures and that is due to the saturation of this amount of furfural with undesirable materials [16]. 8 8.5 9 9.5 10 10.5 11 75 80 85 90 95100105110115120125130 v is co si ty a t 1 0 0 °c , c st temperatur, °c solvent to lube oil 1:1 furfural:nmp,(80: 20) furfural:nmp,(60: 40) furfural:nmp,(40: 60) 80 82 84 86 88 90 92 94 96 98 100 75 80 85 90 95100105110115120125130 v is co si ty n id e x temperatur, °c solvent to lube oil 1:1 furfural:nmp,(80:20) furfural:nmp,(60:40) furfural:nmp,(40:60) furfural:nmp,(20:80) extraction of aromatic hydrocarbons from lube oil using different co-solvent 88 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net fig. 9, effect of extraction temperature on raffinate viscosity index at various solvent to co-solvent ratio (at solvent to lube oil ratio 2:1) fig. 10, effect of extraction temperature on raffinate viscosity index at various solvent to co-solvent ratio (at solvent to lube oil ratio 3:1) effect of extraction temperature and furfural to co-solvent (nmp) ratio for stock 60 (sea-30) on raffinate yield fig. (11) clearly indicate the effect of extraction temperature on raffinate yield at various solvent to oil ratio and different ratio of furfural and nmp solvent. this explains that yield percentage decreases as the extraction temperature increases. the increasing the value of co-solvent (nmp) to furfural, lead to decrease yield on raffinate phase, due to the aromatics substances dissolve in extraction phase. the effect of increasing solvent to oil ratio results in a deeper extraction this reduces the aromatics content of the raffinate and therefore decreases its raffinate yield. the overall effect of an increase in solvent to oil ratio will be a decrease in raffinate yield but also a decrease of the aromatic content of the raffinate and an improved raffinate quality in extraction process [17]. fig. 11, effect of extraction temperature on raffinate yield at various solvent to co-solvent ratio (at solvent to lube oil ratio 1:1) 85 87 89 91 93 95 97 99 101 75 80 85 90 95100105110115120125130 v is co si ty n id e x temperatur, °c solvent to lube oil 2:1 furfural:nmp,(80:20 ) furfural:nmp,(60:40 ) furfural:nmp,(40:60 ) 90 92 94 96 98 100 102 75 80 85 90 95100105110115120125130 v is co si ty n id e x temperatur, °c solvent to lube oil 3:1 furfural:nmp,(80:20 ) furfural:nmp,(60:40 ) furfural:nmp,(40:60 ) furfural:nmp,(20:80 ) 55 60 65 70 75 80 85 90 95 100 75 80 85 90 95100105110115120125130 y ie ld , w t% temperatur, °c solvent to lube oil 1:1 furfural:n mp,(80:20) furfural:n mp,(60:40) furfural:n mp,(40:60) furfural:n mp,(20:80) ibtehal k. shakir and muslim a. qasim -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 89 conclusions 1. addition one of the two solvents ( formamide and nmp) as a cosolvent can increase solvent power and selectivity of furfural toward aromatic compounds in extraction of aromatics from lube oil cut. 2. the effect of co-solvent to solvent ratio and the solvent to oil ratio is higher than the effect of the temperature on increasing the raffinate viscosity index and decreasing yield, viscosity, and refractive index. 3. viscosity index of lube oil will increase, while viscosity and raffinate yield decreases when increasing extraction temperature, the solvent to oil ratio and cosolvent to furfural ratio. 4. from formamide co-solvent the best condition were extraction temperature at 90 °c, furfural to co-solvent ratio (60:40) and mixed-solvent to lube oil ratio ( 1.5:1) to get the best value of viscosity index 102, viscosity 3.01 sct and raffinate yield 69.23 wt. %. 5. the best condition for nmp cosolvent were 110 °c extraction temperature, (2:1) solvent to lube oil ratio and (60:40 ) furfural to co-solvent ratio, to produce lube oil with 96 viscosity index, 9.10 sct viscosity and 68.50 wt.% raffinate yield. references 1. gupte a. a., landis m. e., and marler d. o.,( 1997 ),“addition of co-solvents to furfural for aromatic extraction”, pct/ us patent 013756. 2. von fuchs, g.h., and anderson, a.p.,(1937), “characterization and properties of petroleum fractions”, industrial and engineering chemistry, no.3, vol. 29, p.319-325. 3. raman n. s., singhal s. k., and basu b., ( 2010), “extraction of aromatics from hydrocarbon oil using n-methyl, 2-pyrrolidone and co-solvent”, us patent, 201 00 243533. 4. baskararao, b.k.,( 1990), “modern petroleum refinery processes”, oxford and ibh publishing co., new delhi, 2nd ed. 5. coto b., van grieken r., pena j.l., espada j.j.,( 2006), “a model to predict physical properties for light lubricating oils and its application to the extraction process by furfural”, chem. eng. sci. 61 4381–4392. 6. espada j.j., coto b., van grieken r., j.m.moreno,( 2008), “simulation of pilot-plant extraction experiments to reduce the aromatic content from lubricating oil”, chem. eng. process. 47 1398–1403. 7. fakhrhoseini s. m., tarakkoli t., hatamipour m s., (2009), “extraction of aromatic hydrocarbons from lube oil using n-hexane as a co-solvent”, separation and purification technology 66,167-170. 8. niigata engineering co., ltd.,( 1976), “300 furfural extraction unit manual”, iraq dura project, oct-5. 9. muslim a. qasim, (2013), "extraction of aromatic hydrocarbons from lube oil using different cosolvent", msc. thesis, chemical engineering department, college of engineering, university of baghdad. 10. abdul-halim a.-k m. and amal khalid shehab k.s.,( 2008), “viscosity index improvement of lubricating oil fraction (sae – 30)”, ijcpe, vol.9 no.3, (september), 5157. 11. fakhrhoseini s. m., m. s. hatamipour, t. tavakkoli and a. montahace, (2009 ),“experimental liquid-liquid equilibrium of (lube cut + furfural +2, 2, 4, tri-methyl pentane) ternary system from t=50 and 70 °c and simulation with nrtl”, ind. eng. chem. res. 48 (20), p.p. 9325-9330. 12. ghafil alibrahem a.,(2010), “evolutionary of extraction base oils unit’s efficiency utilizing extraction of aromatic hydrocarbons from lube oil using different co-solvent 90 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net mixed solvent”, hydrocarbon process, vol.88, no.9, p. 155-160. 13. duininck j.,( 2006), “furfural extraction process guide”. re. gs.06.52373, ch. 2, shell research and technology centery, amsterdam. 14. sequeira, a., sherman, p.b., j. v. and mc bride, e.o., (1979 ),“ engineering and design. lubricants and hydraulic fluids”, hydrocarbon processing, vol.58, no.9, p. 155-160. 15. kosters, w. c. g., “ petroleum additives and their functions”, chemistry and industry, vol. 15, no. 2, p.p. 220 – 223, 1977. 16. abdul-halim a.-k., hussain k. h, and rafal j. s., “the effect of solvent extraction of light lubricating oil on viscosity index and chemical composition’, ijcpe, vol.8 no.4, (december), 1-12, 2007. 17. jain a.k., sarkar d.k. & jchopra s., “lube refining with nmp solvent”, iipd r&d division, engineers indian, 2003. iraqi journal of chemical and petroleum engineering vol.14 no.1 (march 2013) 3946 issn: 1997-4884 studying the performance of refrigeration units powered by solar panel venus majeed hameed* and maha ali hussein** *university of nahrain college of engineering mechanical engineering department ** dijlah collage university refrigeration and air conditioning department abstract an experimental study was conducted to determine the performance of a solar electric refrigeration system. the system contained flat photovoltaic solar panel which absorbs the solar energy and convert it to electrical energy, used to run the refrigeration cycle. two refrigeration cycles with electrical solar panel were used over a period of 12 months, the first one with classical parts known in refrigeration cycle, while the second one introduced heat exchanger which improves the coefficient of performance by saving the consumed energy. the coefficient of performance of these refrigeration cycles with compressor efficiency 85% are 2.102 and 2.57 respectively. the overall efficiency of the two systems are 18.9% and 23.13%. keywords solar panel, solar electric refrigeration, refrigeration system, photovoltaic cell, coefficient of performance introduction during the last few decades energy consumption for cooling has increased dramatically in most countries. the main reasons for the increasing energy demand for summer airconditioning and refrigeration are the increased thermal loads, increased living standards and comfort demands in conjunction with architectural characteristics and trends. during the summer the demand for electricity increases due to the extensive use of refrigeration systems, which increase the peak electric load, causing major problems in the electric supply. the last few years exhibited an increasing interest, based on research and development, has been concentrated on utilization of energy sources, like solar energy, wind energy, hydrogen energy, etc, due to the increasing of oil price. among these sources, solar energy is a highly popular source due to the following facts: direct and easy usability, renewable and continuity, being safe, being free, environment friendly and not being under the control of anyone [1]. the use of solar energy to drive refrigeration systems has a great interest, this type of solar energy is called solar electrical refrigeration, which consists mainly of photovoltaic panels and an electrical refrigeration device. whose efficiency and cost vary widely depending on the material and the manufacturing methods they are made from. the photovoltaic cells produce electricity iraqi journal of chemical and petroleum engineering university of baghdad college of engineering studying the performance of refrigeration units powered by solar panel 40 ijcpe vol.14 no.1 (march 2013) -available online at: www.iasj.net without noise or air pollution from a clean source [2]. in this work solar electrical panel are used to drive an improved refrigeration system and improve electrical refrigeration system, and then estimated the overall efficiency in the two cases. refrigeration system prior to discussing how solar energy could potentially provide refrigeration, it is appropriate to review the basic principles of operation for vapor compression refrigeration cycles that form the foundation for nearly all conventional refrigeration. in the vapor compression cycle, as can be seen in figs.(1) &(2), cooling is provided in the evaporator as low temperature refrigerant entering the evaporator as a mixture of liquid and vapor at state 1 is vaporized by thermal input from the load. the remaining equipment in the system reclaims the refrigerant and restores it to a condition in which it can be used again to provide cooling. the vapor exiting the evaporator at state 2 in a saturated (2s) or slightly superheated (3s) condition enters a compressor that raises the pressure and, consequently, the temperature of the refrigerant. the high pressure hot refrigerant at state 3 enters a condenser that uses ambient air to cool the refrigerant to its saturation temperature prior to fully condensing to a liquid at state 4. the high-pressure liquid is then throttled to a lower pressure, which causes some of the refrigerant to vaporize as its temperature is reduced. the low temperature liquid that remains is available to produce useful refrigeration[3]. a schematic of the vapor compression cycle is shown in fig. (1) and a corresponding enthalpy – pressure diagram for the refrigerant is shown in fig. (2). the coefficient of performance (cop) of vapor compression refrigeration system is taken as a method of performance efficiency of any refrigeration cycle which defined as: [a. klein2005] cop= ...(1) where: q is the evaporator heat energy (kj) w is the compressor input work (kj) fig. 1, schematic of a vapor compression refrigeration cycle fig. 2, pressure-enthalpy diagram solar electric refrigeration the solar electric refrigeration is the refrigeration that runs on the solar energy. the solar system of the solar refrigerator comprises of the solar panel that collects the solar energy. the solar panels are fitted with photovoltaic (pv) cells that convert the solar energy into electrical energy and store it in the battery. during the normal running of the solar refrigerator the power is supplied directly by the solar panel, but when the output power of solar panels is less, the additional compressor exp. valve t cond. t evap. const. entropy 2s 3s enthalpy p re ss u re venus majeed hameed* and maha ali hussein -available online at: www.iasj.net ijcpe vol.14 no.1 (march 2013) 41 power is supplied by the battery. the battery is recharged when excess amount of power is produced by the solar panels [4]. the rate of electrical power capable of being generated by a pv system is typically provided by manufacturers of pv modules for standard rating conditions, i.e., incident solar radiation of 1,000 w/m2 and a module temperature of 25°c. unfortunately, pv modules will operate over a wide range of conditions that are rarely as favorable as the rating condition. in addition, the power produced by a pv array is as variable as the solar resource from which it is derived. the performance of a pv module, expressed in terms of its current-voltage and power-voltage characteristics, principally depends on the solar radiation and module temperature. efficiency of solar panel is defined by the ratio of power w (watt) to the product of solar panel surface area as(m 2 ) and the direct irradiation of solar beam ip (w/m 2 ) [5]. …(2) experimental work many parts are connected together in order to operate the refrigeration system. the experimental parts of a solar refrigeration system are illustrated in fig. (3). there are two main parts in the experiment, the first part introducing the energy. this part is responsible for producing power or electrical energy: a) pv panel the voltage and the power of pv cells are very small in order to supply a device. for this reason, many cells are combined together in a pv panel with common electrical output. one of the main features of the panel is the peak power. the peak power is the power from the photovoltaic when the solar irradiance is 1000 w in every square meter.the operating voltage and current are another important characteristic of the panel. the photovoltaic panels today are constructed in a way that they produce power equal to 12 v in order to charge the 12 v batteries. pv panel which is used in this work has a specifications illustrated in table (1). table 1, pv panel specification photovoltic system specifications dimensions 1600×1300×35 output peak power 180 w max.voltage 35.3 v max. current 5.36 a test condition 1000 w/m 2 , 25c о panel type fixed tilt panel tilt 35 о , 55 о b) voltage regulator this device controls the current flux from the pv to the batteries and allow to overcoming the change in the voltage supply by the sun through the pv panel from the sunrise to sunset. when the battery is fully charged, the voltage regulator decreases the current not to overcharge the battery. when the battery is overcharged, the operational life is decreased. c) battery the electrical energy is stored to the batteries in order to be provided in intervals with minimum solar irradiance (during nights, cloudy days). generally the batteries used for pv systems are the same as the ones used in cars (lead type). the output supply of batteries is dc with voltage about 12 v. d) inverter since the refrigerator driven motor is operated on a.c, an inverter is needed. this device converts d.c to a.c. to operate the refrigerator. studying the performance of refrigeration units powered by solar panel 42 ijcpe vol.14 no.1 (march 2013) -available online at: www.iasj.net e) load the term load indicates the total number of electrical appliances that they will be operated with the electrical energy provided by the pv. for a pv system to be well designed the electrical energy that these appliances consume in a time interval of one month, should be equal or less to the energy produced by the system in the same time interval. for every electrical appliance, various parameters should be known before connecting them the pv system: the type of the operational current the value of the operational voltage the power dissipated during its operation. fig. 3, solar electricrefrigeration system fig. 4, schematic diagram of solar electric refrigeration experimental analysis 1. ( pv) panel data in order to study sun radiation for baghdad city its location should be known as shown in table (2). table 2, location identification location identification city baghdad latitude 33.35° longitude 44.4167° fixed pv panel are chosen for this study with two different tilts. the selected angles are 35° and 55° since they give the biggest radiation collector angles. the study is taken over a year with average radiation intensity for a month as shown in table (3). table 3, monthly solar radiations results month solar radiation (kwh/m 2 /day) @35° solar radiation (kwh/m 2 /day) @55° 1 4.9 5.25 2 5.4 5.51 3 5.91 5.62 4 6.47 5.69 5 5.97 4.98 6 5.88 4.73 7 6.16 4.99 8 6.55 5.62 9 6.0 5.57 10 5.93 5.95 11 5.23 5.56 12 4.67 5.19 avg. 5.76 5.39 fig. 5, solar radiation vs. month at 35° and 55° tilt 3 volt.regulator inverter 2 1 throttle evaporato r comp. controlle r condencer 4 venus majeed hameed* and maha ali hussein -available online at: www.iasj.net ijcpe vol.14 no.1 (march 2013) 43 to calculate the efficiency of the used solar panel maximum voltage should be calculated first as follows:[5,6] wmax=imax×vmax ... (3) = 5.36 × 35.3 = 189.2 w the solar panel area: as= 2.08 m 2 the solar panel output power( wo) is calculated from: ...(4) where: ip= solar radiation in w/m 2 ir= reference solar radiation which equal (1000 w/m 2 ) wo= output power so the efficiency of the solar panel: %091.9 2080 2.189 1000 .. maxmax max          ssr spr p sp a w ai w aii i w ai w eff  the calculated results for the whole year is shown in table (4). table 4, results of solar panel month solar radiation , ip, (w/m 2 ) @35° work (w) solar radiation , ip, (w/m 2 ) @55° work (w) 1 490 92.7 525 99.33 2 540 102.16 551 104.24 3 591 111.81 562 106.33 4 647 122.41 569 107.65 5 597 112.95 498 94.22 6 588 111.24 473 89.49 7 616 116.54 499 94.41 8 655 123.92 562 106.33 9 600 113.52 557 105.38 10 593 112.19 595 112.57 11 532 100.65 556 105.19 12 467 88.35 519 98.19 avg. 576 108.97 539 101.97 the obtained pv panel current and power can be shown in fig.(6) and fig.(7) respectively. fig. 6, relationship between pv panel current produced for every month over a year at 35° and 55° tilt fig. 7, relationship between pv panel power produced for every month over a year at 35° and 55° tilt 2. refrigeration system operating conditions and performance two refrigeration cycles are used in this work as following: 2.1. classical refrigeration unit freon (12) is used as a working fluid, as shown in fig. (8). fig. 8, classical refrigeration cycle suction line t1= 266.65k , p1=24 psi discharge line t2=324.85k,p2=200 psi liquid line t3=320.45kp3=p2=200 psi evap. comp. 1 4 sat. vapor two phase throttle cond. 2 3 sat. liquid super heated vapor studying the performance of refrigeration units powered by solar panel 44 ijcpe vol.14 no.1 (march 2013) -available online at: www.iasj.net  from ph chart (r12) h1=353 kj/kg h2=393 kj/kg h3=h4=254 kj/kg q-w=∆h (5) the process between point 3 and 4 is isenthalpic throttling process, there is no work [7] ∆h=0 h4=h3 the compressor is operated adiabatically, and its efficiency is 85% compressor: -wcomح= ∆h = (h2 h1)/0.85 wcomp. = (393 – 353)/0.85 = 47 kj/kg evaporator: qevap. = ∆h = h1 – h4 qevap. = 353 – 254 = 99kj/kg 102.2 47 99 . .  comp evap w q cop a modification on the refrigeration system is introduced with the same supplying amount of electrical energy but increasing the refrigeration performance. 2.2. improvement of refrigeration system a heat exchanger is introduced in order to save energy. the location of heat exchanger is shown in fig. (9): fig. 9, improved refrigeration cycle by introducing a heat exchanger suction line t1= 269.35 k, p1=21 psi discharge line t2=323.35k,p2=170 psi liquid line t3=318.35k,p3=p2=170 psi  from ph chart (r12) h1=360 kj/kg h2=398 kj/kg h3=h4=245 kj/kg q w = ∆h the process between point 3 and 4 is isenthalpic throttling process and there is no work ∆h=0 h4=h3 the compressor is adiabatic, and the condenser and evaporator do no work compressor: -wcomp.= ∆h = (h2 h1)/0.85 wcom = (398 – 360)/0.85 = 44.7 kj/kg evaporator: qevap. = ∆h = h1 – h4 qevap. = 360 – 245 = 115 kj/kg 57.2 7.44 115 . .  comp evap w q cop 3. the overall systems efficiencies the biggest advantage of using solar panels for refrigeration is the simple construction and high overall efficiency when combined with a conventional vapor compression system. combination of the efficiencies in eq.(1) and eq.(2) gives the overall efficiency of a solar electric cooling system: [5] overall eff.= 1effe. of the systemwith classical refrigeration unit = 9 ×2.102 =18.9% 2effe. of the system with improved refrigeration unit = 9× 2.57 = 23.13% 4 evaporator comp. 1 2 3 condenser super heated vapor super heated vapor sat. liquid two phase capillary tube suction line venus majeed hameed* and maha ali hussein -available online at: www.iasj.net ijcpe vol.14 no.1 (march 2013) 45 discussion a solar panel was used to supply about 100 w to operate a refrigeration cycle in two cases. this test was made over 24-hour period during 12 months in baghdad, with 10 hour as an average light day time and 576 w/m 2 as an average radiation. the efficiency of the used solar panel is 9%, which was calculated from the data obtained. on the other hand the cop for the refrigeration cycle in two cases was calculated, the first case consists of classical parts for refrigeration unit as shown in fig. (8). in this case the evaporator temperature between -6.5 and -18 c° and the condenser temperature between 47.3 and 51.7 c°. in the second cycle a heat exchanger was introduced between the throttle and the suction line as shown in fig. (9). this modification increased the cop of the cycle by decreasing the consumption of energy, for the second cycle the evaporator temperature between -3.8° and -15 c and the condenser temperature between 45.2 and 50.2°c. thus, the cop of the classical refrigeration cycle is 2.102 and for the improved cycle is 2.57. for the two cycles above the refrigerant vapor was compressed using 100 watt piston compressor with an approximated of efficiency 85%. to increase the cycle efficiency, there is another pv panel with better performance but an optimization between price and power produces must be done. refrigeration with energy produced from pv panel is environmental friendly and avoid the electrical shut down through the day and without any monthly depts for the use of electricity. also, it decreases the public electrical peak load through the day. conclusion the overall system efficiency can be defined as the combination of the coefficient of performance (cop) for refrigeration cycle with solar panel efficiency. the cop of the first refrigeration cycle was low, therefore an improved was made in the second refrigeration cycle by introducing a heat exchanger between the section line and expansion valve. inspite of the lower photovoltic panel efficiency, it was found that the used of solar power to drive the refrigration cycle had many advantage. nomenclature area (m 2 ) a coefficient of performance cop enthalpy (kj) h current (a) i solar radiation perpendicular to collector surface (w/m 2 ) ip reference solar radiation equal 1000 (w/m 2 ) ir pressure p photovoltaic panel pv heat energy (w) q voltage (v) v work (w) w references 1kais j. al-jumaily, ali m. alsalihi, osama t. al-tai, 2010” evaluation of meteosat-8 measurements using daily global solar radiation for two stations in iraq”, international journal ofenergy and environment, volume 1, pp.635-642. 2jasim m. abdulateef, kamaruzzaman sopian, m. a. alghoul, mohd yusof sulaiman, azami zaharim and ibrahim ahmad, 2007 “solar absorption refrigeration system using new working fluid pairs”, international journal of energy, issue 3, vol. 1. 3a. klein, and douglas t. reindl, 2005 “solar refrigeration”, ashrae journal, vol. 47, no. 9. studying the performance of refrigeration units powered by solar panel 46 ijcpe vol.14 no.1 (march 2013) -available online at: www.iasj.net 4haresh khemani, 2009 “what is solar refrigerator”, www.solimpeks.com. 5d.s. kim, c.a. infante ferreira, 2008 “ solar refrigeration options a state of the art review “, international journal of refrigeration, vol. 3, pp. 3-15. 6efstratios chaniotakis, 2001 “modeling and analysis of water cooled photovoltaic’s”, department ofmechanical engineering university of strathclyde. 7 smith, j.m.; van ness, h.c.; and abbott, m.m., 1996" introduction to chemical engineering thermodynamics ", 5 th edition, published by mc-graw-hill company. 8r.c. dowing, 1974, ashrae transaction, paper no. 1313. http://www.brighthub.com/members/hareshsk.aspx http://www.solimpeks.com/ ijcpe vol.10 no.1 (march 2009) iraqi journal of chemical and petroleum engineering vol.10 no.1 (march2009) 53-57 issn: 1997-4884 kinetic studies of hydrodesulfurization of vacuum distillate abdul-halim a.k.mohammed * , abdul-monaem a.k. ** and hiadar a.a. ** * chemical engineering department college of engineering university of baghdad – iraq ** chemical engineering department college of engineering university of tikrit – iraq abstract vacuum gas oil (611-833)k was distilled from kirkuk crude oil, which was obtained by blending the following fraction, light vacuum gas oil (611 650) k, medium vacuum gas oil (650-690)k, heavy vacuum gas oil (690-727)k and very heavy vacuum gas oil (727-833)k. the vacuum gas oil was hydrotreated on a commercial cobalt-molybdenum alumina catalyst presulfied at specified condition in a laboratory trickle bed reactor. the reaction temperature varied from (583-643)k over liquid hourly space velocity ranging between (1.5-3.75)h-1 , hydrogen pressure was kept constant at 3.5 mpa with a hydrogen to oil ratio of about 250 l/l the conversion results for desulfurization appeared to obey the second order kinetics. according to this model rate constants for desulfurization reaction were calculated. finally, the apparent activation energy (ea), enthalpy of activation ( h*) and entropy ( s*) were calculated based on the values of rate constant (k). the calculated values of ea, h* and s* were 74.657 kj/mole, 74.712 kj/mole and 167.132 j/mole.k, respectively. introduction kinetic studies using individual sulfur compounds have usually indicated that simple first-order kinetic with respect to sulfur are the predominate mechanism by which sulfur is removed from the organic material as hydrogen sulfide. however, there is still much learned about the relative rates of reaction exhibited by the various compounds present in petroleum [1]. residue hydrodesulfurization is considerably more complex than the hydrodesulfrization of model organic sulfur compounds or, for that matter, narrowboiling petroleum fractions. in published studies of the kinetic of residua hydrodesulfurization, one of the three approaches has generally been taken. 1-the reaction can be described in terms of simple first-order expression. frye and mosby [2] showed that the hydrodesulfurization kinetic of the three compounds found in cycle oil feed stock followed a first order model. it was proposed that the hds reaction of petroleum distillates were also first order [3]. the kirkuk reduced kinetics follow first order model [4]. 2-the reaction of hydrodesulfurizatio can be described by use of two simultaneous first-order expressions, one expression for easy-to-remove sulfur and a separate expression for difficult-to-remove sulfur. the hydrodesulfurization of an arabian lighitatmospheric residuum could be represented as the sum of two competing first order reaction [5]. arey et al [6] fitted kinetic data for heavy vacuum gas oil, atmospheric residues, vacuum residue and deasphaltened residue according to this model. 3-the reaction of hydrodesulfurization can be described using a second-order treatment. application of this model to kuwait vacuum residue using two type of catalyst gives a liner relation. mohammed et al[7] show that the hds of qaiyarah deasphaltened university of baghdad college of engineering iraqi journal of chemical and petroleum engineering kinetic study of hydrodesulfurization of vacuum distillate 54 ijcpe vol.10 no.1 (march 2009) reduced crude followed second order kinetic. the kinetic of the catalytic hds of the deasphaltened oil and non-asphaltenic fraction obtained from the atmospheric residue of the greek thasos crude oil follow second order model[8] for completely wetting effects are negligible, the governing equation for the reaction performance and for first-order reaction may be expressed as[9].             lhsv k c c aout ainln (1) where: cain: inlet concentration, weight percent. caout: outlet concentration, weight percent. k: reaction rate constant,h-1 lhsv: liquid hourly space velocity. and when the hydrodesulfurizatiopn reaction supposed to be second order the expression for second order –γ = kc2a gives enough 2 lhsv k cc ainaout  11 (2) equation 1 and 2 indicate that in the absence of back mixing and liquid hold up effect or incomplete catalyst wetting effects, a log-log of lhsv vs cc and c c ainaoutaout ain 111 ln       should be straight line with slope equal to unity. also at constant lhsv the conversion should be independent of catalyst bed length. when two simultaneous first order expression equation 3 may be used [10]              lhsv k s lhsv k scain 2 02 1 01 exp)(exp)( (3) where: (s1)0 and (s2)0: the initial compositions of easy and difficult to remove sulfur. k1 and k2 : the reaction rate constant of easy and difficult to remove sulfur. if back mixing is insignificant and conversion is highly related to liquid-hold up then modified henry and gilbert equation holds (9) when the desulfurization governs the first-order reaction it can be expressed as:          1 )( ln lhsv kl c c aout ain (4) where: l: length of catalyst bed β: empirical constant it can be shown from equation (4)that a log-log plot of lhsv vs c c aout ain 1 ln       should yield straight line with a slope equal to (1-β). different values of β have been reported [11,12]. henry and gilbert took β = 1/3. a similar effect of lhsv and catalyst bed length on conversion in the absence of back mixing was also predicated on the basis of catalyst wetting model of mears (13) equation 5          1 )( ln lhsv kl c c aout ain (5) where: γ : empirical constant mears took γ = 0.32 a log-log plot of ln lhsv vs c c aout ain 1       gives a straight line with a slope equal to (1-γ) abdul-halim a.k.mohammed, abdul-monaem a.k. and hiadar a.a. 55 ijcpe vol.10 no.1 (march 2009) experimental work feed stock the feed stock in this investigation was the vacuum gas oil which was obtained by distillation unit of atmospheric reduced crude (arc) of kirkuk crude oil in baiji refinery vacuum distillation unit. the percentage of vgo was 45vol.% of the original atmospheric reduced crude. the properties of the vgo is given in table 1.the feed stock preparation includes blending the fraction lvgo (611-650)k, mvgo (650-690)k, hvgo (690-727)k, and very hvgo (727-833)k with the percentage volumes 13.67,21.67,27,and37.66 respectively. the resulted mixture represents actual kirkuk crude oil vacuum distillate. table 1: the properties of feed stock (vgo) specification value sp.gr. at 60/60 f 0.911 api °gravity, 23.858 viscosity ,cs at 323 k 373 k 11.563 2.784 pour point, k 302 flash point, k 465 aniline point, k 325 ccr, wt% 0.58 sulfur content, wt% 2.5 the catalyst the catalyst employed for the hds process in this investigation was the commercial ni-mo-alumina type catalyst .the properties of this catalyst are identified in table 2. table 2: the catalyst properties properties value moo3, wt% 15.0 nio, wt% 3.0 sio2,wt% 1.1 na2o,wt% 0.07 fe, wt% 0.04 so2,wt% 2.0 al2o3,wt% balance physical specification value form extrudate surface area, m 2 /g 180 pore volume, cm 3 /g 0.5 bulk density, g/cm 3 0.67 mean particle diameter, mm 1.8 mean particle length, mm 4 the hydrodesulfyrization experiment the hds runs were performed in a laboratory continuous high-pressure unit employing an up-flow concurrent trickle bed reactor. the reactor is stainless, and heats resisting steel with dimensions of 65cm length, and 2cm diameter. experiments were undertaken by varying the reactor temperature (583643)k and ,lhsv (1.53-3.75)h-1 ,while the pressure kept constant at 2.5 mpa. details about the experimental procedure were described in other reference [14]. kinetic study of hydrodesulfurization of vacuum distillate 56 ijcpe vol.10 no.1 (march 2009) test methods the sulfur content of the feed stock and products were determined according to bomb method (astm: d 129-64). this method consists mainly of bomb, sample cup, firing wire, and cotton wicking. the sample is oxidized by combustion in a bomb containing oxygen under pressure 4mpa. the sulfur as sulfate in the bomb washings is determined gravimetrically as barium sulfate. results and discussion data obtained from the laboratory unit for the desulfurization of the vacuum gas oil were analyzed by the available kinetics models outlined in introduction. data were correlated with first order kinetics equation assuming ideal plug flow models including the effect of fluid flow : results show that hydrodesulfurization data have a deviation from the first order kinetics models as shown in figure 1. the results are treated accordingly to hold-up model of henry and gilbert (equation 4) and the incomplete catalyst-wetting model of mears (equation 5) as shown in figure 2 the plots according to equation (4) give straight lines with slope equal to (1-β). the calculated values of β varied from 0.135-0.39. the range of the values is not far from those obtained by henry and gilbert(9) and mohammedetal(15). second order kinetics model equation (2) is also used to fit the obtained data by plotting lhsv vs cc sinsout 111  as shown in figure 3. these plots give straight lines with slopes equal to rate constants. the values of rate constant calculated at different temperatures are given in table 3. the activation energy measures the amount of energy which reactants must have before they can overcome the barrier between them and the product state. the activation energy for the desulfurization reaction was calculated by using the arrhenius equation, which satisfies the relationship between the rate of the reaction and temperature (1). )/( exp rtea ak   (6) where: a: equation constant, frequency factor or exponential factor ea: activation energy (kj/mol) r: gas constant (kj/mol.k) t: temperature of reaction (k) a plot of ln k vs 1/t as shown in figure 4 gives a straight line with a slope equal to –ea/rt from which the activation energy was calculated. the activation energy for desulfurization was found to be 74.657 kj/mol. this value is not far from value 87.1 kj/mol obtained by mann.at(16). the activation enthalpy and entropy for the desulfurization reaction was calculated by using the equation (7), which was obtained from the absolute reaction rate theory [17] )/exp()/exp( ** rthrs h f k t k  (7) where: k: transmission coefficient f: boltzman constant, j/k h: plank constant, j/s δs*: activation entropy , j/mol.k δh*: activation enthalpy, kj/mol a plot of ln k/t vs 1/t in figure 5 gives a straight line with slope equals to δh*/r from which the activation enthalpy can be calculated. the intercept of this line which is equal to ln(kt/h)+(δs*/r)may be used to calculate the activation entropy δs*. the values of calculated δh* and δs* are 74.712 kj/mol, and 167.132 j/mol.k respectively. abdul-halim a.k.mohammed, abdul-monaem a.k. and hiadar a.a. 57 ijcpe vol.10 no.1 (march 2009) table 3: results of activation energy, enthalpy and entropy calculations conclusions 1-the hydrodesulfurization reaction of vacuum gas oil distilled from krikuk crude obey the second order kinetics. 2the reaction rate constants for hydrodesulfurization reaction is varying with the reaction temperature. the calculated values of reaction rate based on the reaction temperature increasing were 0.421,0.593,1.076,and 1.856 respectively 3-activation energy , ennthalpy and entropy of hydrosulphurization reaction were calculated. references 1speight, j. g. and “the desulfurization of heavy oil and residua” ,1981. 2speight, j. g. and moschoped, s. e. acs preper., dev. pet. chem.,1979:24:910. 3chu, c. i. and wang i., ind. eng. chem. process. des. dev.,1982:21:338. 4mohammed, a-h. a-k. and hankish k., j. petrol. res. 1985:4(2):37. 5hummadi, k. k.,ph. d. thesis, baghdad university 1999. 6arey, w. f. jr., balckwell, n. e., and reichle, a. d. seventh world petroleum congress 1968:4:167. 7mohammed,a-h. a-k. and hankish k. and abbas k., fuel, 1988:6(6):593. 8parayannakos n., applied catalysis, 1986:24:99 9henry h. c. and gilbert j. b., i&ec proc. dev., 1973:12(3):328 10flin, r. a., benther, h. and schmid, e. k., petroleum refiner, 1961:40(4):140 11hochman j. m., efforn e., i&ec. fund., 1969:8:63 12mohunta d. m. and laddha g. s., chem. eng. sci., 1956:20:1069 13mears d. e. and hulburt h. m., chem. react. eng., acs, monograph series,1974:123:218 14areff, h. a., ms. sc.thesis, tikrit university 2001 15mohammed, a-h. a-k., and hankish, k., fuel , 1985:july:vol.64:921-24 16mann, r. s., sambi, i. s., and khulbe, c. k., ind. eng. chem. reas. 1988:27:1788-92 17rahman, a. m., ms. sc., thesis, baghdad university 2000 temperature k k (hr.wt.%) -1 ea * kj/mol δha * kj/mol δsa * j/mol.k 583 0.421 74.657 74.712 167.132 603 0.593 623 1.076 643 1.856 characterization and cracking activity of zeolite prepared from local kaolin ijcpe vol.11 no.2 (june 2010) iraqi journal of chemical and petroleum engineering vol.11 no.2 (june2010) 35-42 issn: 1997-4884 characterization and cracking activity of zeolite prepared from local kaolin abdul halim a.k. mohammed, samar karim and ameel m. rahman* chemical engineering department-college of engineering-baghdad university *biochemical engineering department abstract the synthesis of zeolite nax from locally available kaolin has been studied. the operating conditions for zeolite nax production from kaolin with good crystallinity were as follows; a gel formation step of metakaolin in alkaline medium in presence of additional silica to crystallize the zeolite was achieved at 60 oc for 1 hr,and with stirring. in ageing step of the reactants at room temperature for 5 days and crystallization step at 87±2 oc for 24 hr. the catalytic activity of catalyst prepared from local kaolin was studied by using cumene cracking as a model for catalytic cracking and compared with standard hy zeolite and hx zeolite catalysts. the activity test was carried out in a laboratory continuous flow unit with fixed bed reactor at duration time in the range 10-240 minutes, temperature 823 k, and lhsv 1 h-1. the prepared and the standard catalysts were characterized by atomic absorption, x-ray diffraction analysis, fourier transform infrared spectroscopy, surface area and pore volume. ________________________________________________________________________________________________ introduction most catalysts used in commercial catalytic cracking units today are either amorphous synthetic silica-alumina combinations or mixtures of amorphous synthetic silicaalumina and crystalline synthetic silica-alumina catalysts called zeolites or moleculars sieves[1]. the advantages of the zeolite catalysts over the natural and synthetic amorphous catalysts are: higher activity, higher gasoline yields at a given conversion, production of gasoline containing a larger percentage of paraffinic and aromatic hydrocarbons, lower coke yield (and therefore usually a larger throughput at a given conversion level), increased isobutane production, and ability to go to higher conversions per pass without overcracking[1,2]. despite the fact that activated natural clays have not been used as cracking catalysts for a long time, awareness of their characteristics is important since natural clays continue to be included in the composition of synthetic catalysts in order to reduce their cost. this technique, initially used in the production of silica alumina catalysts, is used today on a large scale in the production of zeolitic catalysts [3]. clay minerals of the kaolin group are convenient starting materials for the synthesis of zeolites. kaolin clay must be sufficient plastic so that is can be molded and remain strong in the green and dry state, must not be so plastic that it shrinks and distorts on drying [4]. kaolin type clays or clay minerals have the general composition al2o3.2sio2.2-4h2o, which makes such clays preferred for synthesis of zeolite types [5]. kaolin is inexpensive, naturally occurring, abundant material and was employed as the sole source of silica and alumina [6]. it is largely available in iraq; particularly in al-ga'ara areas of western iraq that have four regions (dewkkla, samhat, telafef and bir mlusi) [4]. kaolinite is the major mineral component of kaolin, which may contain impurities such as quartz, illites, smectites, and feldspars [7]. when kaolin –type clay is heated, it will undergo several transitions. the first of these takes place at about (550600°c), and produces the disordered metakaolin phase (metastable phase) by an endothermic dehydroxylation university of baghdad college of engineering iraqi journal of chemical and petroleum engineering characterization and cracking activity of zeolite prepared from local kaolin ijcpe vol.11 no.2 (june 2010) 36 reaction [8], and it has been reported that metakaolin is more reactive under chemical treatments, this transformation occurs with the loss of structural water with a reorganization of the structure; only a small part of alo6 octahedral is maintained, while the rest are transformed into much more reactive tetraand penta coordinated units [7]. the metakaolin is then stable to about 935-950°c where it rearranges to give a defect aluminum–silicon spinel, which is also referred to as a γ-alumina type structure. the so called γ-al2o3 phase converts to mullite 3al2o3.2sio2 at 1050°c, as shown in the following equations [9]: 2al2si2o5 (oh) 4    c600550 2al2si2o7 + 4h2o kaolin metakaolin 2al2si2o7    c950925 si3al4o12 + sio2 metakaolin spinel 3si3al4o12   c o 1015 2si2al6o13 + 5sio5 spinel mulli cristablite metakaolin is believed to be a defect phase in which the tetrahedral silica layers of the original clay structure are largely retained. it is know to be more reactive, therefore it is used as a starting material for the synthesis of zeolite [9]. zeolites (aluminosilicates) are crystalline clays that can be either natural minerals or prepared synthetically by crystallizing silica and alumina solutions [10]. at present some 39 naturally occurring zeolite species have been recorded and their structures determined. in addition more than 100 synthetic species with no know natural counterparts have been confirmed as new zeolite and the majority a wait full structural determination [11]. cumene (isopropyl-benzene) is a typical aromatic compound in the gasoline pool. thus the reactions of these important aromatics are quite significant for refiners [12]. the chemistry and kinetics of cumene cracking have been received the largest attraction form researchers due to its simplicity. corma and wojeiechowski have reviewed this reaction in detail [13]. long-chain aromatics also draw the attention of researchers because they represent the aromatics in gas oil. corma and co-workers [14,15] reported that these compounds crack by a number of competing reaction pathways including dealkylation, side chain cracking, and self alkylation. thus, although cumene cracking has been used extensively as a test reaction to investigate the characteristics of newly developed cracking catalysts [12], locally limited research has developed on the cracking of cumene. frillete et al. [16] studied the cumene cracking and found that the conversion was low at 510oc over nax-zeolite (6 mole%), more extensive over cax-zeolite (59 mole% at 470°c), but not so extensive over amorphous aluminosilicate. kazuo and hiroshi [17] examined the effects of the degree of ion exchange and the silica to alumina mole ratio on the cumene cracking activity of faujasitetype zeolite. when they studied the activity of five different faujasite –type zeolites with different silica /alumina mole ratio; (na-x2.5, na-y5,na-y3.25 ,na-y3.85 , and na-y4.6) by cumene cracking ,and treated the zeolites under the same conditions ,they found that when the sio2/al2o3 mole ratio was 5.1 and the reaction temperatures 300, 350, 400, and 450°c the cumene conversion (mole%) would be 0.5, 10.8, 35.2, and 62.5, respectively. and they found that when sodium ions in na-form zeolite are replace with polyvalent metal ions or nh4 ions, the order of activity is la>nh4>ca>na; where the activity would be determined by both the acidity and the acid strength. the catalytic activity of la-na-y at 350°c becomes notable after the cation exchange exceed 50%, and reached the maximum value 100mol% cumene conversion at 87% exchange . the same phenomenon was observe by james [18] who examined the cumene cracking for a series of faujasites ion-exchange with alkali and alkaline earth elements (k, na, li, ba, sr, ca, and mg) using micro-reactor. the order of cumene conversion is mg>ca>sr>ba>li>na>k. peter et al. [19] studied dealkylation of cumene over zeolite y in hydrogen form pretreated at temperatures between 500 and 800°c and they found that the main products were benzene and propylene and they calculated the conversion data from the concentration of benzene in the product. donald and wojciechowski [20] used cumene cracking reaction to evaluate the activity of 100/140 mesh of lay zeolite catalyst. cumene accumulative conversion increases as the temperature increases from 360 to 500°c and increasing catalyst/oil (wt/wt) ratio from 0.004 – 0.016 at the same time on stream. also it was observed that the accumulative conversion increases and reach a stable value at 200 sec time on stream at the same above conditions. lin et al. [21] studied the cumene fractional conversion over lay zeolite vs. time on stream at several reaction temperatures (360-500°c), several space times (2.510 ×10-3 gs/mol), and two particle sizes (-20 + 40 mesh) and (-60+80 mesh). a 10.8 mol% initial cumene conversion was observed at 360°c and 5.2×10-3 gs/mol. during the first 5 min and the rate of reaction decline as the time on stream increases at the same conditions, the conversion reaches 7.5 mol% at 141 min time on stream. abdul halim a.k. mohammed, samar karim and ameel m. rahman ijcpe vol.11 no.2 (june 2010) 37 this work deal with the production of hx zeolite from locally kaolin and test it is cracking activity by cumene cracking. experimental work materials materials properties cumene supplied by molecular weight density boiling point hy-zeolite(cbv600) supplied by na2o(wt %) sio2/al2o3 mole ratio unit cell pore volume surface area synthetic zeolite type 13x supplied by na2o(wt%) sio2/al2o3 mole ratio unit cell pore volume surface area kaolin(locally) the used kaolin is available in sio2(wt%) al2o3(wt%) na2o(wt%) fe2o3(wt%) tio2(wt%) cao(wt%) mgo(wt%) k2o(wt%) l.o.i(wt%) colloidal sodium silicate ammonium nitrate supplied by molecular weight sodium hydroxide supplied by molecular weight nitrogen bdh with 98% purity 120.20 g/mol 0.860 g/cm 3 423k zeolyst international (uwe ohlrogge (vf)) as a powder . 0.2 5 24.3 å 0.92 660 m 2 /g. linde company as pellets (3*5)mm . 14 2.2 24.9 å 0.35 340 ( m 2 /g) al-dewekhala quarry in alenbar region. 53.49 30.83 0.22 2.15 2.82 0.056 0.056 0.422 9.956 bdh limited poole england .80.04 g/mole . bdh limited poole england 40 g/mole . high grade quality (purity 99.9 %) of nitrogen obtained from al-mansor factory preparation of h-x zeolite from kaolin h-x zeolite is prepared by steps consisting essentially of: 1. calcination of the raw kaolin at 550°c for 1 hr in a programmable electrical furnace (model n2o/h,max. temp. 1340 o c), after that, the kaolinite can be transformed to metakaolinite. 2. sieving the metakaolinite to a particle size ≤75 μm. 3. the gel was prepared by mixing 5 ml of naoh solution (10 wt% naoh) with 1g colloidal sodium silicate. at low alkali concentration the reaction did not take place, because the crystallization speed was so low that no crystalline species were obtained as observed by caballero et al. [22], and de lucas et al. [23, 24]. so, at sodium hydroxide concentrations below 10%, the desired zeolite may not form [25]. the resulting solution was mixed with 1 g of metakaolinite in a 1000 ml round –bottom flask with two necks: one neck fitted with water –cooling reflux condenser, and the other neck with thermometer to measure the temperature, where the reaction was carried at atmospheric pressure. agitation and heating of the flask were done by oil bath on magnetic heater stirrer, where the temperature of the mixture in the heated flask was kept constant by using voltage regulator . the gel formation step was achieved at 60°c, for 1 hr. caballero et al. [22] found that the stirring speed does not exert a strong influence on the zeolite relative crystallinity value, and it was only necessary to guarantee good gel homogeneity. 4.the aging step was done at room temperature and for 5 days [26] without agitation. the product will be more crystalline when aging the gel at low temperature before carrying out the high temperature crystallization [26]. 5.crystallization step was done at temperature 87±2°c [27] for 24 hours without agitation. at the end, the flask was quenching in cold water. 6.the next steps were decantation and washing several times with deionezed water until the ph value equal to 10 [28] then the powder was filtered in buckner funnel with the aid of a vacuum pump. the drying was achieved at 120°c for 12 hr using a programmable electrical furnace(model n2o/h,max. temp. 1340 o c). after that, the product was milled to convert it to a fine powder, which was sieved to a particles size ≤ 75μm. 7. a 100 g of catalyst powder was prepared by mixing 25 g [4,29] of the binding material which is kaolin with 75g of catalyst powder.the resulted dry powder was mixed with deionezed water manually using spatula to form a paste. 8. the paste was placed in a cylindrical cavity of 2 cm inside diameter, and 10 cm long. extrudates shapes were obtained when the paste was compressed manually. very uniform spaghetti shaped paste was ejected and put in a porcelain crucible at room temperature overnight. characterization and cracking activity of zeolite prepared from local kaolin ijcpe vol.11 no.2 (june 2010) 38 9. extrudates were dried in a programmable electrical furnace at 120°c for 2 hr [4, 30]. the calcination was done at 550°c for 2 hr [4, 31]. then the calcined extrudates were cut into 4-8 mm long. 10. hydrogen-form catalysts were prepared by ion exchange method of the original catalyst with 3 n ammonium nitrite solution [32, 33]. thus 120 g of ammonium nitrite in 500 ml deionized water was contacted with 50 g of catalyst in a continuous stirring for 2 hr at 90°c [28]. the ph of the solution was held constant at 7.5, and socking this catalyst in a fresh solution of ammonium nitrite with ph 7.5 at room temperature overnight. the extrudates were washed, filtered, and dried at 120°c for 2 hours [28]. the dried extrudates were calcined at 550°c for 4 hr. during calcination ammonia and water are liberated and decationized h-form zeolite is formed. preparation of h-x zeolite from na-x standard zeolite hydrogen-form standard nax zeolite was prepared by ion exchange method of the original na-x catalyst with 3 n ammonium nitrite solution [32,33]. thus ,120 g of ammonium nitrite in 500 ml deionized water was contacted with 50 g of catalyst in a continuous stirring for 2 hr at 90°c [28]. the ph of the solution was held constant at 7.5, and socking this catalyst in a fresh solution of ammonium nitrite with ph 7.5 at room temperature overnight. this procedure repeated twice. the extrudates were washed , filtered, and dried at 120°c for 2 hours [28]. the dried extrudates were calcined at 550°c for 4 hr. during calcination ammonia and water are liberated and decationized h-form is formed. hy-zeolite shaping 1. a 70 g of hy-zeolite as a powder was mixed with 30 g montmorillonite clay as binder. the preferred binder content percent of mixing is between 15-30% as noticed by allain et al. [34], martens et al. [35]. the chemical composition of montmorillonite is: 51.3%sio2, 28.73%al2o3, 1.3%na2o, 3.4% cao, and 3.3 % mgo. the resulting mixture was mixed with water to form a paste. 2. steps 8 and 9 used for prepared nax zeolite were repeated to finalize hy-zeolite preparation. activity test the cracking activity tests were performed in a continuous laboratory unit. the unit consists of feed tank, flow meter , feed pump, evaporator , reactor, separator , collector and cooler with appropriate control system for heating.the reactor was a carbon steel tube with an outside diameter of 1.9 cm, 2 mm thick and 80 cm length .a fresh catalyst was charged to the reactor between two layers of inert materials (glass balls).the activity was carried out at 823k, lhsv 1 h -1 , atmospheric pressure and at duration time ranging from 10-240 minutes. test method for liquid product analysis liquid products were trapped by condenser at -5c, collected periodically and analyzed by using gas chromatography. the gas chromatography model packard 438a was used for the analysis .this device equipped with column of 0.25mm diameter ,50 m length and fid detector. results and discussion x-ray diffraction the xrd test was used in the present work to study the crystal structure of the prepared catalysts. figure1. represent the x-ray pattern of the prepared na x zeolite. this pattern was compared with x-ray data of standard zeolites reported by [9] ,x-ray pattern of standard zeolite for hy (figure 1) and hx (figure 2). it was found that prepared nax zeolite has a 52.17% crystallinity at d spacing 14.64e -8 ±0.1 , and has approximately the same crystal structure as the standard type nax-zeolite . some differences are found among the x-ray diffraction data which can be attributed to the distribution of cation (sodium), different in silica to alumina mole ratio, and different in a mode of preparation. fig. 1 x-ray diffraction spectrum for the preparedna-x zeolite catalyst after adding the binder . abdul halim a.k. mohammed, samar karim and ameel m. rahman ijcpe vol.11 no.2 (june 2010) 39 fig. 3 x-ray diffraction spectrum for the standard na-x zeolite catalyst after adding the binder. fourier transforms infra red spectroscopy (ftir) ftir was used in this study to identify the structural properties of the catalysts hx-zeolite and prepared nax zeolite before ion exchange, which contains fundamentals vibrations of the framework of silicaalumina tetrahedral, can be used in characterization of zeolite type. these vibrations include symmetric and asymmetric stretching and bending mode of si (al)4 tetrahedral , and double ring vibration. figures 4 and 5 show the spectrum of hx-zeolite and prepared na x zeolite (before ion exchanges). it was observed that the characteristic bands for the vibrations of hx-zeolite (fig.4) and ftir data from breack [9] and chandrasekhar et al. [27], are symmetric due to asymmetric stretch at 970 and 1100 cm -1 and symmetric stretch at 750, 670, and 690 cm -1 , double ring 560 cm -1 and si(al)-o bands 455 cm -1 are clearly found in the prepared nax zeolite so, the ftir spectral analysis results support the xrd inferences. figure 4 ftir spectrum of standard na-x zeolite before ion exchange. figure 5 ftir spectrum of prepared na-x zeolite before ion exchange. surface area the physical properties of different catalyst were presented in table 1 shows that commercial y-zeolite powder has 660 m 2 /g surface area and the surface area decreases to 546 m 2 /g after adding a binder and shaped from a powder to extradite form. the surface area depends on many parameters such as type of binder used during shaping process and si/al ratio. as si/al increases the surface area decreases as noted for hy zeolite after adding binder. bokhoven et al. [36] observed that the external surface area and pore volume for hmor-26 significantly higher than that of hmor-57 and found that increase in surface area and pore volume related to lower content of silica.thus after adding a binder, si/al mol ratio increases from 5 to 6 and that surface area and pore volume decrease also because of applying pressure throughout the extrusion to form zeolite extradites was low. this is in agreement with the results published by gates et al. [37]. fig. 2 x-ray diffraction spectrum for the standard hy zeolite catalyst after adding the binder . characterization and cracking activity of zeolite prepared from local kaolin ijcpe vol.11 no.2 (june 2010) 40 table 2, physical characteristics of the catalysts. catalyst hy zeolite powder hy zeolite + binder hx zeolite prepared hx zeolite pore volume cm 3 /gm 0.92 0.850 0.320 0.318 bulk density g/cm 3 0.356 0.596 0.602 porosity (%) 88.01 46.03 45.58 surface area m 2 /g 660.0 546.00 299.70 290.20 si2o/al2o3 mole ratio 5.0 6.0 2.2 2.8 catalyst activity cumene cracking was chosen as a model to evaluate the activity of the prepared hx zeolite and to compare the results with the activity of the standard catalysts hy and hx catalysts. cumene conversions over the prepared and standard catalysts were determined at different duration times( time on stream). figure 6 represents the activity comparison of prepared and standard catalysts at temperature 823 k and lhsv 1 h -1 . as shown in this figure that the activity of cracking catalysts take the following order ; standard hy zeolite > prepared hx zeolite > standard hx zeolite . at 10 min, the cumene conversions were 52.38, 33.54 and 49.14 mol% for hy, hx and prepared hx zeolite, respectively . it was observed from this figure as the time on stream increases the cumene conversion decreases. cumene conversions at 240 min decreased to 33.19, 21.2 and 20 mol%, respectively. usually the activity of cracking catalysts declines rapidly because of the accumulation of carbonaceous deposits on the catalyst surface at high time on stream values. the same phenomena was observed and reported in previous studies donald and wojciechowski [20],lin et al. [21], william [38] and yu liu and pinnavaia [39] . fig. 6 the activity comparison of prepared and standard catalysts at temperature 823 k and lhsv 1 h -1 . conclusions: according to the results obtained from this study, the following conclusions are deduced: 1. it was found from x-ray and ftir tests that prepared na x zeolite has a crystallinity 52.17% and nearly has the same crystal structure as the standard type 13x-zeolite with silica to alumina molar ratio 2.8 , and catalyst a did not represented any type of zeolite and it has very low activity. 2. it was observed that the activity of cracking catalysts take the following order ; standard hy zeolite > prepared hx zeolite > standard hx zeolite . at temperature 823 k , lhsv 1 h -1 , and 10 min, the cumene conversions were 52.38, 33.54 and 49.14 mol% for hy, hx and prepared hx zeolite, respectively . references: (1)thomas,c. l. ," catalytic processes and proven catalyst", academic press inc.publishers, new york,(1970). (2)gary ,j. h., "petroleum refining-technology and economics" ,4 th ed. , marcel dekker, inc., new york,(2001) . (3) serge raseev ,"thermal and catalytic processes in petroleum refining" ,marcel dekker,inc., new york,(2003). (4) nada,a. z., "preparation of zeolites 3a and 5a from locally available raw materials and abdul halim a.k. mohammed, samar karim and ameel m. rahman ijcpe vol.11 no.2 (june 2010) 41 their extrusion with different binders", m.sc. thesis, university of baghdad,(2002). (5) de oliveira , f. m., and ortiz, n. , "process for whitening kaolin",u.s. patent ,5,242,874,(1993). (6) haden w. l. , metuchen , and dzierzanowski f. j. ,"method for making synthetic zeolitic material", u.s. ,patent, 2,992,068,(1961). (7) belver,c. , banares,m. a., and vicentc,m. a., "chemical activation of a kaolinite under acid and alkaline conditions" , chemical material, vol.14, 2033,(2002). (8) corma, a., "inorganic solid acids and their use in acid-catalyzed hydrocarbon reactions", chem.rev. , vol.95, 559-614, (1995). (9) break, d. w. , "zeolite molecular sieves structure chemistry and use", john wiley and sons , new york,(1974). (10) xiaobo zheng , “a computational investigation of hydrocarbon cracking :gas phase and heterogeneous catalytic reaction on zeolites”, ph.d thesis, university of arizona,(2006) . (11) suchuchchai nuanklai ," effects of particle size and hydrothermal treatment of y-zeolite on catalytic cracking of n-octane ", m.sc. thesis, university of chulalongkorn, (2004) . (12)al-khattaf, s., " the role of temperature in 1,3di-iso-propylbenzene catalytic reactions using fcc catalysts" ,the arabian journal for science and engineering, vol.30, no.1b, 13,(2005). (13) corma, a., and wojciechowski, b.w., "the catalytic cracking of cumene", catal. rev.sci. eng.,vol. 24 , 1-65,(1982). (14)corma,a., miguel,p.j., orchilles,a.v., koermer,g. and madon,r., "cracking of longchain alkyl aromatics on usy zeolite catalysts", j. catal., vol. 135, 35 45,(1992). (15)corma,a. , miguel,p.j., orchilles,a.v. ,and koermer,g., "zeolite effect on cracking of long-chain alkyl aromatic", j. catal., vol. 145,181-186,(1994). (16) frilette,v. j., weisz,p. b., and golden,r. l.," catalysis by crystalline aluminosilicates i. cracking of hydrocarbon types over sodium and calcium “x” zeolites" , j. catal., vol. 1, issue 4, 301-306,(1962). (17) kazuo, t., and hiroshi ,t. ,"cumene-cracking acitivity of zeolite catalyst", j. catal. , vol. 24, 1, (1972). (18)james, t. r. , "the effect of faujasite cations on acid sites”,j. catal.,vol. 9 , 182,(1967). (19) peter,a. j.,hugo ,e.l., and jan, b. u.,"active sites in zeolites : i. cumene cracking activity of nh4y zeolites after different reactor prtreatments” , j. catal. ,vol. 33, 1730,(1974). (20) donald, b. , and wojciechowski , b. w., "the catalytic cracking of cumene /the kinetics of the dealkylation reaction", j. catal. , vol. 47, 343-357,(1977). (21) lin ,c. c., park,s. w. and hatcher,w.j. , "zeolite catalyst deactivation by coking”, ind. eng.chem. process des. dev. , vol. 22, 609,(1983). (22)caballero,i.,colina, f. g., and costa, j., " synthesis of x-type zeolite from dealuminated kaolin by reaction with sulfuric acid at high temperature" , ind.eng. chm.res. , vol. 46,1029,(2007). (23) de luces, a. , uguina , m. a. , covian , i. , and rodriguez, l., "use of spanish natural clays as additional silica sources to synthesize 13x zeolite from kaolin", ind. eng. chem. res. , vol. 32, 1645,(1993). (24) de luces, a. , uguina , m. a. , covian , i. , and rodriguez, l., "synthesis of 13x zeolite from calcined kaolins and sodium silicate for use in detergents", ind. eng. chem. res. , vol. 31, 2134,(1992). (25) haden , w. l., et al., "synthetic zeolite contact masses and method for making the same", u.s. patent, 3,367,886,(1968). (26) haden,w. l., et al., "method for making a faujasite-type crystalline zeolite", u.s. patent, 3,338,672,(1967). (27) chandrasekhar, s.,and pramada, p.n.,"investigation on the synthesis of zeolite nax from kerala kaolin”, j. of porous materials,vol. 6, 283-297,(1999). (28) zhou, j., min, e., yang h., and zong b., "yzeolite containing composite marerial and a process for preparing the same”, u.s. patent, 7,067,449b2, (2006) . (29) ali, a. a. ,"preparation of zeolite type 13x from locally available raw materials", m.sc. thesis, university of baghdad,(2001). (30) flank, w. h. ,et al. , "process for producing molecular sieve bodies", u.s. patent , 4,818,508,(1989). (31) bashir, b. n. , "preparation of zeolite-binder agglomerates from locally available raw materials as cylindrical pellets", m.sc. thesis , university of baghdad,(1997). (32) khalid ,a. s., “modification and characterization of platinum supported characterization and cracking activity of zeolite prepared from local kaolin ijcpe vol.11 no.2 (june 2010) 42 zeolite catalysts”, m.sc. thesis , university of al-nahreen,(1996). (33) anderson, r. b. ,"experimental method in catalytic research", vol. ii, mc graw hill inc., new york, (1979). (34)alline, p.,nagnoux schulz, ph.,and guisnet, m., "hydroisomerization of n-hexane over platinum mazzit and platinum mordenite catalysts kinetics and mechanism", appl. catal. a :general, vol. 152, 227,(1997). (35)martens , g. g. , marin,g. b. , martens ,j. a., jacob, p. a., and baron,g.u. , "a fundamental kinetic model for hydrocracking of c8 to c12 alkanes on pt/us–y zeolites", j. catal. , vol. 195, 253267, (2000). (36) bokhoven, j.a.,tramp, m., koningsbarger, j.t., miller and pieters , j.a.z., lercher, j.a., williams , kung, "an explanation for the enhanced activity for light alkane conversion in mildly steam dealuminated mordenite: the dominant role of adsorption", j. catal., vol. 202, 129140,(2001). (37) gates, b.c.,katzer, j.r., and schuit,g.c., "chemistry of catalytic process" , mc graw hill,(1979). (38) william , j. h., " cracking catalyst deactivation models" , ind. eng.chem. res. dev. , vol. 24, 10-15,(1985). (39) yu liu and thomas j. pinnavaia , " aluminosilicate nanoparticles for catalytic hydrocarbon cracking", j.am.ch.soc. communications , vol.125, 2376-2377, (2003). iraqi journal of chemical and petroleum engineering vol.16 no.2 (june 2015) 917 issn: 1997-4884 furfural degradation in waste water by advanced oxidation process using uv/h2o2 awatif s. alsaqqar * , mohammed sadeq salman ** , waleed. m. abood *** and dhafer f. ali *** * department of civil engineering / college of engineering / baghdad university ** avi-cenna e-learning center / baghdad university *** ministry of industry and minerals / commission of research and industrial development/ solar and environment researches centre abstract furfural is one of the one of pollutants in refinery industrial wastewaters. in this study advanced oxidation process using uv/h2o2 was investigated for furfural degradation in synthetic wastewater. the results from the experimental work showed that the degradation of furfural decreases as its concentration increases, reaching 100% at 50mg/l furfural concentration and increasing the concentration of h2o2 from 250 to 500 mg/l increased furfural removal from 40 to 60%.the degradation of furfural reached 100% after 90 min exposure time using two uv lamps, where it reached 60% using one lamp after 240 min exposure time. the rate of furfural degradation k increased at the ph and initial concentration of furfural decreased, but different h2o2concentrations indicated no significant effects on the reaction rate. uv/h2o2 process is effective for furfural degradation in wastewater at neutral ph where the disposal of such effluents will be within the environmental limitations. key words: furfural, uv/h2o2, degradation, aop. introduction today water pollution is one of the most important environmental problems in the world. industrial wastewaters containing toxic chemicals are the main sources for such problems. petroleum refinery effluents are priority pollutants due to their high polycyclic aromatics content, which are toxic. they encompass a wide range of contaminants at varied concentrations that are harmful. large amounts of water are used in petroleum refinery and significant volumes of wastewater are generated (0.4 – 1.6 times the amount of the crude oil processed) which need to be treated before disposal to water bodies [1, 2]. among these contaminants found in petroleum refinery effluents is a compound known as furfural. furfural is a toxic aromatic aldehyde with the chemical formula c4h3ocho. it is pale yellow or colorless oily liquid and turns into brown or red in the presence of air or light [3, 4]. furfural production is from a mixture of plant raw material (i.e corn seed hulls, cane bagasso and residues of olive extraction) with dilute sulfuric acid (acidic hydrolyaztion).furfural is then iraqi journal of chemical and petroleum engineering university of baghdad college of engineering furfural degradation in waste water by advanced oxidation process using uv/h2o2 10 ijcpe vol.16 no.2 (june 2015) -available online at: www.iasj.net recovered by steam distillation and fractionation with (98-99) % purity [5]. the main use of furfural is in the form of feed stock for furfural alcohol (ffa) this is used as an input for furan resin that is used for foundry binders[6]. furfural and ffa are consumed by chemical industries as intermediate products such as nylons, lubricants and solvents, adhesives, medicines, plastics, urea furan resin synthesis; precision casts and dies [6]. furfural is used as a solvent which has a high capability for separation of multicomponents especially in the petroleum industry to separate sulfur and carbonaceous compounds [3]. acute health effects (short-term) may occur shortly after exposure to furfural which may irritate the skin and eyes. breathing furfural may irritate the nose and throat, also the lungs causing coughing and/ or shortness of breath. higher exposure can cause fluid buildup in the lungs. high concentrations of furfural may cause the person to be dizzy, light headed and to pass out. the chronic health effects (long-term) may occur at some time after exposure to furfural and can last for months or years. this may cause skin itching and skin rash (skin allergy). repeated exposure may cause loss in taste sense, numbness of the tongue, headache, tiredness, itchy throat, watery eyes and also may cause liver damage [4, 6, 7].furfural is a very slow biodegradable material (27x 10 -7 g/g biomass) which means that it has significant effects on the aquatic life and fishes [8]. the presence of furfural increase the toxicity of industrial effluents and its removal may be difficult or impossible by conventional treatment processes used in most industries. many technologies have been developed to treat effluents containing furfural. basheer et al., (2011) reviewed that petroleum refinery effluents were treated by coagulation, chemical oxidation, adsorption, biological techniques, membrane filtration and catalytic wet air oxidation [1]. belay et al. (1997) investigated the metabolism of furfural by methanococcus delta under anaerobic conditions; the results showed the ability of these micro organisms to transfer furfural to furfural alcohol [8]. hassan et al. (2012) used activated sludge to provide micro organisms for furfural degradation [3]. sulaymon and abood, (2005) tested adsorption of furfural onto activated carbon [9], where ghazi, (2012) used agricultural waste for furfural adsorption [6]. sulaymon and hayfa, (2014) used activated carbon and dead micro organisms from anaerobic sludge for adsorption/biosorption of furfural [10]. all these methods transfer the contaminants from one media to another therefore a second treatment process is required to eliminate these contaminants. several solutions have been proposed and compared with these traditional methods. in recent years the application of photo catalysis technique in wastewater treatment was tested. these techniques are known as advance oxidation processes (aops) which can completely degrade organic pollutants into harmless inorganic substances like co2 and h2o under moderate conditions [2]. these processes are widely used in the decomposing of organic products in industrial wastewater and groundwater owing to their complete mineralization, produce no sludge, high reaction rates and operate under ambient temperature and pressure conditions [1, 8, 11, 12, 13]. aops are defined as potential processes that are capable of producing hydroxyl radicals ( • oh), which are extraordinary reactive oxidations (oxidation potential 2.8 v) in sufficient awatif s. alsaqqar, mohammed sadeq salman , waleed. m. abood and dhafer f. ali -available online at: www.iasj.net ijcpe vol.16 no.2 (june 2015) 11 quantity for mineralizing a majority of complex organic materials to carbon dioxide, water and inorganic ions. majority of aop processes like cavitation, photo catalytic oxidation and fenton chemistry are performed by applying various combinations of homogeneous photo fenton (fe iii), ozone and tio2 such as uv/o3, uv/h2o2, uv/h2o2/o3, o3/tio2, tio2/h2o2/o3 and more. these combinations use energy to produce highly reactive intermediaries with high oxidation or reduction potential. the hydroxyl radicals may be obtained from powerful oxidants, such as h2o2 and o3, combined with irradiation.[2,13, 14, 15]. basheer et al. (2011) summarized several treatment producers for petroleum refinery effluents using aops; it was observed that the reduction in cod and doc may reach 90% [1]. kang et al. (2009) used uv/o3 for the degradation of furfural wastewater. they achieved complete degradation within 3 hr under optimum conditions [13]. nevak (2010) applied fe(iii)/h2o2/solar-uv process to petrochemical refinery wastewater, the reduction in cod reached 49% after 8 hr of exposure to solar radiation [2]. the objective of this study is to describe experimentally the feasibility of furfural removal from synthetic wastewater by uv/h2o2technology under different operational conditions, furfural initial concentration, h2o2 dosage, number of uv lamps used and ph of the solution. experimental work synthetic wastewater containing different concentrations of furfural was tested by uv/h2o2technology under different operational conditions in a photo reactor. 1materials a. furfural (c4h3ocho) has a chemical structure shown in fig. (1), of molecular weight 96.06 gm/mol, has synonyms of 2furaldehycle, furyl and 2 furyl methanol [7].the physical properties of furfural are listed in table (1). fig. 1, chemical structure of furfural [9] table (1), recorded physical properties of furfural [9] color colorless to yellow and red-brown when exposure to light and air odor aromatic odor as benzaldehy de specific gravity 20 o c 1.1598 flash point, open cup o c 68.3 heat of vaporization (kcal/mol) at 160 o c 9.22 heat of combustion (kcal/mol) 560.2 lower explosive limit in air at (125 o c) vol.% 2.1% ignition temperature o c 39.3 furfural degradation in waste water by advanced oxidation process using uv/h2o2 12 ijcpe vol.16 no.2 (june 2015) -available online at: www.iasj.net b. hydrogen peroxide (h2o2) 50% w/w was obtained in a plastic container of molecular weight 34.01 g/mol supplied by gcc company. the stock solution is to be diluted by distill water for the preparation of different concentrations used in the tests. 2photo reactor units a glass container 3 liter in volume was used as the photo reactor. it is provided witha cooling jacket and a flexible sealed cover (rubber) with holes; two for uv lamps (model no. 5212rl manufactured by sterilight copper company), one hole for supplying air and another for a thermometer. sampling was achieved from a bottom valve as shown in fig. (2) for interval times (30, 60, 90,120,180 and 240 min). experiments were carried out at different operational conditions, furfural concentration (300, 200, 100 and 50) mg/l, h2o2 dosage (1000, 750,500 and 250) mg/l, uv lamps (one and two lamps) and ph solution (3, 7.5 and 11). fig. 2, schematic representation of the photo reactor 3analyses method for the determination of furfural concentrations in a solution, two methods that could be used: the colorimetric analyses by using a spectrophotometer at wave length 430 nm [16]. another method using hplc (high performance liquid chromatography) was used. in this study hplc (type cecil, uk) was used for furfural concentration determination with operation conditions listed below [17]. mobile phase : 5% acetic acid w/v in water methanol (80:20) column : c 18 (5 µm) flow rate : 1 ml/min injection volume : 285 nm 4removal determination percentage of furfural removal was determined using eq.(1). % removal = … (1) where: co is furfural initial concentration and ct furfural concentration at time t during the treatment process. kinetic rate model the progress of the reaction is observed to take place in a completely mixed batch reactor (cmbr), as complete mixing occurs uniformly throughout the reactor with an identical reaction rate (k).common kinetic rate expressions can be evaluated to determine the correlation between the experimental data and the reaction kinetics. most of the degradation processes follow a first order reaction [18] as expressed in eq. (2): … (2) where: k= first-order rate constant,t -1 integrating this eq. (2) yields to … (3) awatif s. alsaqqar, mohammed sadeq salman , waleed. m. abood and dhafer f. ali -available online at: www.iasj.net ijcpe vol.16 no.2 (june 2015) 13 taking the natural logarithm of eq. (3)will obtain the following relationship: ln(ct) ln(co) = -kt … (4) for a first-order reaction, the plot of ln(ct) as a function of t, as shown in eq. (4), will result in a linear relationship. results and discussion 1effect of initial furfural concentrations four initial furfural concentration were investigated (50, 100, 200 and 300) mg/l at ph 7.5, h2o2 dosage 500 mg/l and one uv lamp. fig. 3, removal efficiencies of furfural at different concentrations for h2o2=500mg/l, 1 uv lamp and ph=7.5 the results in fig.(3) show that the degradation of furfural decreases as its concentration increases, reaching 100% at 50mg/l furfural concentration at 120 min, but did not exceed 50% at 200 and 300 mg/l at 240 min. the dosage of 500mg/l h2o2 provided enough • oh radicals for complete degradation of 50 mg/l furfural but was not enough for the degradation of 200300 mg/l. the use of h2o2 is more efficient in the presences of high concentrations of organic compounds (furfural), because the organic matter competes better with h2o2for the generation of • oh radicals [19]. from these results the optimum h2o2 dosage could be determined for economical purposes. 2effect of h2o2 dosage fig (4) shows the effect of various h2o2 concentrations (250, 500, 750 and 1000) mg/l on the furfural removal efficiency. increasing the concentration of h2o2 from 250 to 500 mg/l increases the furfural removal from 40 to 60%.at higher concentrationsh2o2 will absorb more uv that will produce more •oh radicals which will degraded more furfural. but overdosing of h2o2 (more than 500mg/l) may cause simultaneous reactions that could: consume h2o2 or cause self decomposition of h2o2 to oxygen and water where this will reduce the generation of • oh radicals. it is also observed that the reaction of • oh with excess h2o2willform weak radicals • ho2 (hydroperoxyl with oxidation potential 1.7 v). hydroperoxyl radicals may react with h2o2 to produce also water and oxygen. so these radicals (•oh and • ho2) will act as inhibiting agents and the removal efficiency of furfural decreases [20].these reactions are shown in the following equations: h2o2 + hυ (uv energy) → 2 • oh h2o2 + • oh→ • ho2+ h2o h2o2+ • ho2→ • oh +h2o +o2 2 • oh → h2o2 2 • ho2→ h2o2 +o2 • oh + • ho2→ h2o2+ o2 0 20 40 60 80 100 120 0 30 60 90 120 150 180 210 240 r e m o v a l e ff ic ie n ce % time (min) 300 mg/l 200 mg/l 100 mg/l 50 mg/l furfural degradation in waste water by advanced oxidation process using uv/h2o2 14 ijcpe vol.16 no.2 (june 2015) -available online at: www.iasj.net fig. 4, removal efficiencies of furfural at different h2o2 concentrations for furfural concentration= 200 mg/l, 1uv lamp and ph=7.5 3effect of light intensity fig. (5), shows the effects of light intensity on the degradation of furfural. the intensity of light was adjusted by using one or two lamps at constant furfural concentration of 200 mg/l, h2o2 dosage 500 mg/l and ph 7.5. as the intensity of light increased, the removal of furfural accelerated because more light intensity is available and more • oh radicals are produced under the action of uv/h2o2. fig. 5, effect of uv intensity on removal efficiency of furfural 200 mg/l in concentration, h2o2 =500mg/l and ph=7.5 the rate of photolysis of h2o2 depends directly on the incident power. at low uv power the photolysis of h2o2 is limited. while, at high uv power more • oh radicals are produced upon the photo dissociation of h2o2, hence furfural removal rate increases. it appears that the uv power lies within the linear range and hence all the photons provided were effectively used [21]. the degradation of furfural reached 100% after 90 min exposure time using two uv lamps, where it reached 60% using one lamp after 240 min exposure time. 4effect of ph fig. (6) shows that the degradation rate of furfural was higher in acidic solution ph 3 (about 80% furfural removal).this ph value was the best for the uv/h2o2 process as • oh radicals are free for reaction. at high ph values oh ions will increase in the solution and may react with • oh radicals where this will decrease furfural degradation. also in alkaline medium the oxidizing species hydroperoxy anion (ho2  ) are formed and these anions react with • oh radicals and residual h2o2 consequently lowering the removal rate of furfural. hydrogen peroxide is most stable in the ph range 3-4, but its decomposition rate rapidly increases with increasing ph above ph 7.5 [21]. fig. 6, effect of ph on removal efficiency of furfural= 200 mg/l, 1uv and h2o2= 500mg/l 0 20 40 60 80 100 0 30 60 90 120 150 180 210 240 r e m o v a l e ff ic ie n ce % time (min) 1000 mg/l h2o2 0 20 40 60 80 100 120 0 30 60 90 120 150 180 210 240 r e m o v a l e ff ic ie n ce % time (min) 1 uv 2 uv 0 20 40 60 80 100 120 0 30 60 90 120 150 180 210 240 r e m o v a l e ff ic ie n ce % time (min) ph=3 ph=7.5 ph=11 awatif s. alsaqqar, mohammed sadeq salman , waleed. m. abood and dhafer f. ali -available online at: www.iasj.net ijcpe vol.16 no.2 (june 2015) 15 all the results in section 4 were at ph 7.5 and not 3. from these results furfural removal was observed at ph 7.5. hence this could be considered if real wastewaters are to be treated by this process. no need to add chemicals to the wastewater to decrease its ph for furfural degradation. the wastewater then will be discharged to water bodies at neutral ph which is recommended for effluents disposal. 5kinetic results eq. (4) was applied for all of the experimental results to find the rate of reaction (degradation of furfural by uv/h2o2). a plot of ln ct/co vs. time is illustrated in fig. (7). the slope of the line in this plot is equal to the firstorder rate constant k and the intercept is equal to in (c0). the calculated values of k (min -1 ) for the different operation conditions are listed in table (2). fig. 7, first order rate constant of furfural removal by uv/h2o2 at 100 mg/l concentration, 500 mg/l h2o2 and 1 uv table (2) first order rate constant k min -1 at different operation conditions exp. ph furfural conc. mg/l h2o2mg /l no. of uv lamps kmin -1 r 2 1 3 200 500 1 0.007 0.905 2 7.5 200 500 1 0.0034 0.894 3 11 200 500 1 0.0024 0.652 4 7.5 200 500 1 0.0034 0.8937 5 7.5 300 500 1 0.0037 0.817 6 7.5 100 500 1 0.0077 0.902 7 7.5 50 500 1 0.0183 0.995 8 7.5 200 1000 1 0.0026 0.995 9 7.5 200 750 1 0.0026 0.705 10 7.5 200 500 1 0.0034 0.894 11 7.5 200 250 1 0.0024 0.894 12 7.5 200 500 2 0.0257 0.933 0 0.5 1 1.5 2 0 30 60 90 120 150 180 210 240 270 300 ln ( c t/ c o ) time (min) y=0.007x+0.358 r2=0.902 furfural degradation in waste water by advanced oxidation process using uv/h2o2 16 ijcpe vol.16 no.2 (june 2015) -available online at: www.iasj.net table (2) shows that the rate of furfural degradation k increases as the ph decreases, 0.007, 0.0034 and 0.0024min -1 for ph 3, 7.5 and 11 respectively. for different furfural initial concentrations the rate of degradation increased k 0.0037, 0.0034 0.0077 and 0.0183min -1 as the initial concentration of furfural decreased (300, 200, 100 and50) mg/l where k was nearly the same for 200300 mg/l furfural initial concentration. the k values using different dosages of h2o2were 0.0024, 0.0034, 0.0026 and 0.0026 min -1 for 250, 500, 750 and 1000 mg/l respectively, indicating no significant effects on the reaction. all the above results had been achieved using one uv lamp, the k value increased using two uv lamps to 0.0257 min -1 which is higher than k value 0.0034min -1 using one uv lamp for the degradation of 500 mg/l furfural concentration conclusions 1the degradation of furfural decreases as its concentration increases, reaching 100% at 50mg/l furfural concentration at 120 min, but did not exceed 50% at 200 and 300 mg/l at 240 min reaction time. 2increasing the concentration of h2o2 from 250 to 500 mg/l increased furfural removal from 40 to 60%. high concentrations of h2o2 (more than 500mg/l) act as a radical scavenger. 3the degradation of furfural reached 100% after 90 min exposure time using two uv lamps, where it reached 60% using one lamp after 240 min exposure time. 4the rate of furfural degradation k increased as the ph and initial concentration of furfural decreased, but different h2o2concentrations indicated no significant effects on the reaction rate. from the above conclusions, uv/h2o2 process if effective for furfural degradation in wastewater at neutral ph where the disposal of such effluents will be within the environmental limitations. references 1basheer hasan diyauddeen, wan mohd ashri and a. r. abdul aziz, (2011).”treatment technologies for petroleum refinery effluents: a review”. process safety and environmental protection, vol.89, pp95-105. 2neval baycan parilti, (2010). “treatment of petrochemical industry wastewater by solar oxidation process using the boxwilson experimental design method”. ekoloji, vol.19, no.77, pp9-15. 3hassan hooshi, nima afshar ghotli, alireza and shahram abbasi, (2012). “using activated sludge system to reduce furfural concentration in a refinery wastewater”. advance in environmental biology, vol. 6, no.8, pp2378-2383. 4new jersey department of health and senior services, (2000). “hazardous substance fact sheet”. cas no.98-01-1, dot no. un 1199. 5al-saady, nirjs h.m.,(2000). “production of furfural from cornseed hulls“, m.sc. thesis, university of baghdad, college of science for women. 6ghazi aidan, (2012). “agricultural wastes and activated carbon from them for furfural removal from water solutions”, life science journal, vol.9, no.3, pp 2501-2505. 7osha, (2000). “occupational safety and health administration of furfural “, u.s. dept. of labor. 8bely n., r. boopathy and g. voskuilen, (1997). “anaerobic awatif s. alsaqqar, mohammed sadeq salman , waleed. m. abood and dhafer f. ali -available online at: www.iasj.net ijcpe vol.16 no.2 (june 2015) 17 transformation of furfural by methanococcus delta lh”, applied and environmental microbiology, vol. 63, no. 5, pp2092-2094. 9sulaymon a. h. and abood w. mohammed, (2005). “removal of furfural from waste water by activated carbon”, journal of engineering/college of eng./university of baghdad. vol.11, no.3, pp.523-531. 10sulaymon a. h. and hayfaa l. swadi, (2014). “adsorption/biosorption of furfural and mercury onto granular activated carbon/granular dead of anaerobic sludge”, journal of chemical and pharmaceutical research, vol. 6, no. 2, pp 570-579. 11tchohanoglous, g., burton f. l. and stensel d., (2003). “wastewater engineering treatment and reuse”, mc-crawhill co., 4th edition, hong kong, china. 12watts r. j., (1998). “hazardous waste, source, pathways, receptors”, john willy, new york. 13kahg chun-li, tang xiao-jian, jiao xin-qian, guo ping, quan fumin and lin xue-yu, (2009). “degradation of furfural by uv/o3 technology”. chem. res. chinese universities, vol.25, no.4, pp451454. 14zanta c. l., huitle c.and a. martínez, (2009). “ degradation of 2hydroxybenzoic acid by advanced oxidation processes”, brazilian journal of chemical engineering , vol. 26, no. 3, pp. 503–513 15ivy dos santos oliveira, anuj k chandel, messias borges silva and silvio silvério da silva (2013). ”pre-treatment of sugarcane bagasse by advanced oxidation process “, sustainable chemical processes journal, pp 1-20. 16foste r. and lesile w.,(1971) “encyclopedia of industrial chemical analysis”, john wiely, new york,vol. 13, pp. 232-239. 17susan z. m., mohammed i. t., badawi a. z., hazeim m. a. and elrasheed a. g., (2009). “identification and quantification of 5-hydroxymethyl furfural hmf in some sugar containing foodsby hplc”, pakistan journal of nutrition no.8, vol.9, pp.13911396. 18crittenden john c., trussel r. rhodes, (2005). “water treatment principle and design” john wiley & sons,inc. new jersey, usa. 19tony m. a., purcell p. j. and zhao y. q.,(2012). “oil refinery wastewater treatment using physicochemical, fenton and photo fenton oxidation processes”, journal of environmental scienceand health, part a, vol. 47,pp. 435-440. 20kruithof j. c., p. c. kampand b. j. martijn, (2007). “uv/h2o2 treatment: a practical solution for organic contaminant control and primary disinfection”, ozone science engineering, vol. 29, pp.273–280. 21muruganandham m. and swaminathan m., (2004), “photochemical oxidation of reactive azo dye with uv/h2o2 process”, dyes and pigments, vol.62, pp 269–275. iraqi journal of chemical and petroleum engineering vol.14 no.2 (june 2013) 1320 issn: 1997-4884 kinetic study and simulation of oleic acid esterification in different type of reactors ammar s. abbas and sura m. abbas chemical engineering department, college of engineering – university of baghdad abstract esterification reaction is most important reaction in biodiesel production. in this study, oleic acid was used as a suggested feedstock to study and simulate production of biodiesel. batch esterification of oleic acid was carried out at operating conditions; temperature from 40 to 70 °c, ethanol to oleic acid molar ratio from 1/1 to 6/1, h2so4 as the catalyst 1 and 5% wt of oleic acid, reaction time up to 180 min. the optimum conditions for the esterification reaction were molar ratio of ethanol/oleic acid 6/1, 5%wt h2so4 relative to oleic acid, 70 °c, 90 min and conversion of oleic 0.92. the activation energy for the suggested model was 26625 j/mole for forward reaction and 42189 j/mole for equilibrium constant. the obtained results simulated to other types of reactors with different operating conditions using reactop cascade package. the conversion of oleic acid of simulation results at optimum operating conditions was 0.97 for isothermal batch and plug flow reactors, 0.67 for isothermal cstr, while the conversions of oleic acid in the adiabatic mode were 0.82, 0.40, 0.74 for batch, cstr, pfr reactors respectively. key word: oleic acid, esterification, kinetic study, simulation. introduction energy sources can be classified into three groups fossil, fissile, and renewable. the term fossil refers to an earlier geological age. fossil fuels were formed many years ago and are not renewable. the fossil energy sources are petroleum, coal, bitumen, natural gas, oil shale, and tar sands. the main fissile energy sources are uranium and thorium [1]. one of the main and most important non-renewable energy sources is oil, the production rate of oil is expected to peak in the next few years therefore, the world needs an alternative and renewable energy source that are able to meet world energy needing [2]. the renewable energy sources such as biomass, hydro, wind, solar (thermal and photovoltaic), geothermal, marine, and hydrogen will play an important role in the future. it is predicted that in 2025, approximately half of the global energy supply will come from renewable energy, and electricity generation from renewable will be more than 80% of the total global electricity supply [3, 4]. biomass can be converted into liquid and gaseous fuels through thermochemical and biological methods. biofuel is a non-polluting, locally available, accessible, sustainable, and reliable fuel obtained from renewable sources [5]. liquid biofuels fall into iraqi journal of chemical and petroleum engineering university of baghdad college of engineering kinetic study and simulation of oleic acid esterification in different type of reactors 14 ijcpe vol.14 no.2 (june 2013) -available online at: www.iasj.net the following categories: (a) vegetable oils and biodiesels, (b) alcohols, and (c) bio-crude and synthetic oils [1]. esterification is one of the most important reactions in chemical industry; and the relative reaction is usually conducted by using, in general, homogeneous acid catalysts [6]. esterification reaction carried out between carboxylic acids (free fatty acids) and alcohols with the presence of an acid catalyst (such as sulfuric acid, orqanic sulfonic acid, and hydrochloric acid) to form ester and water (see equatin 1) [7]. ↔ …(1) ffa alcohol ester water the present work, intend to produce ethyl ester (biodiesel) from the oleic acid by esterification process. the effects of reaction temperature, amount of catalyst, and the molar ratio alcohol/oil were considered. also, the kinetic of oleic acid esterification were studied and the results were simulated to different type of reactors and operating conditions. experimental work materials 1. oleic acid, obtained from local markets. the specific gravity of the oleic acid is 0.895, bdh chemicals ltd. 2. ethyl alcohol obtained from local markets with specific gravity is 0.7692 (88 to 90 wt. %). 3. sulfuric acid as an acid catalyst obtained from local markets, the purity of this acid is 98% (sp.gr. is 1.84) aldrich. 4. sodium hydroxide for titration (riedel_dehaen ag seelze_hannover chem. rian, plozchen, dab7, b.p.1968 m.wt. 40). 5. phenolphthalein (as indicator), fluka. apparatus the apparatus used in this study for esterification reaction is shown in figure 1. the batch scale system consists of the followings: 1. heat flat magnetic stirrer (stuart (cb302)/usa. 2. reflux condenser (germany). 3. centrifuge (griffin & george loughborough/britain) 4. mercury thermometer from zero to 250 °c. 5. 3 necks flask (500 ml). 6. sensitive balance. fig. 1, schematic diagram of the reactor esterification of oleic acid the esterification reaction carried out between acid and free fatty acid (ffa) to produce ester (biodiesel) and water. the system was maintained at atmospheric pressure and experiments were carried out at constant temperature. the agitation was kept constant at 300rpm. this process was studied at different percent of ethanol/oil mole ratio of 1/1, 3/1, 6/1 sulfuric acid as a catalyst of 1 and 5 wt% relative to oleic acid, reaction time up to 180 minutes and at different temperatures 40 to 70 ° c. the esterification reactor was loaded with 15 ml (13.43 g) of oleic acid, and the desired amount of ethanol. the mixer was agitated and preheated to ammar s. abbas and sura m. abbas -available online at: www.iasj.net ijcpe vol.14 no.2 (june 2013) 15 the desired temperature and then h2so4 was added. at each period of time (15 or 30 minutes), 5 ml from the mixture reaction was taken and 2 drops of phenolphthalein was added as indicator and titrated with 1 molarity of naoh in order to obtain oleic acid conversion[8]. results and discussion effect of operating temperature and time on the oleic acid conversion figures 2 and 3 show the oleic acid conversion with reaction time at various temperatures and ethanol/oleic acid molar ratio 6/1 with 1 and 5 wt.% of h2so4. time, min 0 20 40 60 80 100 120 140 160 180 200 o le ic a c id c o n v e rs io n 0.0 0.2 0.4 0.6 0.8 1.0 t=40° c t=50° c t=60° c t=70° c etoh/oil = 6/1 h2so4 = 1% fig. 2, effect of the reaction temperature on oleic acid conversion by esterification reaction, 6/1 ethanol/oil mol. ratio and 1 wt% h2so4 time, min 0 20 40 60 80 100 120 140 160 180 200 o le ic a c id c o n v e rs io n 0.0 0.2 0.4 0.6 0.8 1.0 t=40° c t=50° c t=60° c t=70° c etoh/oil = 6/1 h2so4 = 5% fig. 3, effect of the reaction temperature on oleic acid conversion by esterification reaction, 6/1 ethanol/oil mol. ratio and 5 wt% h2so4 as shown in the fig 2 the conversion of oleic acid at 6/1 ethanol/oleic mol. ratio and 1% h2so4 was 0.87 at 70 ° c after 150 minutes and was 0.92 at 70 ° c after 90 minutes with 5% h2so4, which is the highest conversion achieved in this study (as shown in fig.3). the oleic acid conversion increased with increasing temperature. increasing the temperature may causes increase of molecule activity, which means that more molecules have more energy, thus, the possibility of molecule to react increased. these results are in a good agreement with the results of the production of fatty acid ethyl ester (faee) from oleic acid (faa) with short-chain alcohols (ethanol, propanol and butanol) under ultrasonic irradiation reported by hanh et al. [9] the higher conversion for the esterification process was 0.92 at the reaction temperature 60 ° c and 3/1 mol. ratio of ethanol to oleic acid with 5% h2so4 after 2 hours irradiation. effect of ethyl alcohol/oil mol. ratio on the oleic acid conversion molar ratio of ethanol to oleic acid is one of the most important variables that affect the conversion of oleic acid. the experiments of esterification reaction of oleic acid with ethanol were carried out under various ethanol/oil mol. ratios (1/1 to 6/1). figures 4 and 5 show the conversion of oleic acid with reaction time at various ethanol/oleic acid molar ratios using 1 and 5 wt. % h2so4 (as catalyst) at 70 °c. it can be observed that the oleic acid conversion increased from 0.61 at a molar ratio of 1/1 to 0.87 at a molar ratio of 6/1 after 180 min using 1 wt% of h2so4 at 70°c (fig. 4). by using 5 wt% h2so4 at 70°c, the oleic acid conversion increased from 0.87 at 1/1 of ethanol/oil mol. ratio after 180 min kinetic study and simulation of oleic acid esterification in different type of reactors 16 ijcpe vol.14 no.2 (june 2013) -available online at: www.iasj.net to 0.92 at 6/1 ethanol/oil mol. ratio after 90 min, which is the highest conversion achieved in this study (in fig.5). time (min) 0 20 40 60 80 100 120 140 160 180 200 o le ic a c id c o n v e rs io n 0.0 0.2 0.4 0.6 0.8 1.0 etoh/oleic=1/1 etoh/oleic=3/1 etoh/oleic=6/1 temp=70 o c h 2 so 4 =1% fig. 4, effect of the ethyl alcohol/oleic mol. ratio on oleic acid conversion by esterification reaction, at the temperature 70 ° c and 1 wt% h2so4 time (min) 0 20 40 60 80 100 120 140 160 180 200 o le ic a c id c o n v e rs io n 0.0 0.2 0.4 0.6 0.8 1.0 etoh/oleic=1/1 etoh/oleic=3/1 etoh/oleic=6/1 temp=70 o c h 2 so 4 =5% fig. 5, effect of the ethyl alcohol/oleic mol. ratio on oleic acid conversion by esterification reaction, at the temperature 70 ° c and 5 wt% h2so4 increasing in ethanol/oleic mol. ratio causes increasing in the conversion in oleic acid, because the esterification of oleic acid with ethanol is an equilibrium-limited chemical reaction and the position of equilibrium controls the amount of ester formed [10]. these results are a good agreement with those obtained by marchetti and errazu [11], the highest conversion of ffa was 0.96 at the reaction conditions molar ratio of ethanol to acid oil was 6.126, reaction temperature 55° c, reaction time 240 min and 2.261 wt% h2so4. effect of catalyst amount on the oleic acid conversion the amount of catalyst affect on the oleic acid conversion is given in fig.6. it shows the relationships between the oleic acid conversion and time at various catalyst concentrations with ethanol/oleic acid molar ratio 6/1 and 70°c. the oleic acid conversion increased with increasing the catalyst concentration. time (min) 0 20 40 60 80 100 120 140 160 o le ic a c id c o n v e rs io n 0.0 0.2 0.4 0.6 0.8 1.0 1%wt h 2 so 4 5% wt h 2 so 4 fig. 6, effect of the amount of catalyst concentration (h2so4) on oleic acid conversion by esterification reaction, at the temperature 70 ° c and 6/1 ethanol /oleic molar ratio the reaction rate of esterification is directly proportional to the amount of a catalyst, so the catalyst is used to enhance the reaction rate and conversion. the amount of sulfuric acid employed as a catalyst is related to the formation of h + that catalyzes the reaction. kinetic of oleic acid esterification kinetic obtained from laboratory unit are usually play an important role in modeling and scale up designs for new biodiesel production units. the data obtained by differential method of analysis obtained data has ammar s. abbas and sura m. abbas -available online at: www.iasj.net ijcpe vol.14 no.2 (june 2013) 17 been used to find favorable kinetic model for oleic acid esterification. the differential method of analysis deals directly with the differential rate equation to be tested, evaluating all terms in the equation including the derivative -ra, and testing the goodness of fit of the equation with experiment. the conversion of oleic acid (x) fitted by the power degree formula according to the time at certain temperature, and then finding the rate coefficients (k1 and k2) as well as the orders of the reactants and products materials (n1, m1, n2 and m2) using least squares method for the suggested reaction kinetics equation (eqs. 2 to 6). ↔ ...(2) …(3) …(4) …(5) …(6) where: k = rate coefficient of reaction. 1= forward reaction, 2= backward reaction, n and m are the reaction orders. keq = equilibrium constant. ca, cb, cc, cd = reactants and products moles at any time. cae, cbe, cce, cde = reactants and products moles at equilibrium time. according to arrhenius law [12] a plot of ln k vs. 1/t gives a straight line, with slope for e/r to find activation energy for forward reaction and equilibrium reaction (figs.7 and 8). the values of constants in the esterification reaction of oleic acid are summarized in table 1. ln k 1 = -3202.3/t+5.28 1/t 0.0029 0.0030 0.0031 0.0032 ln k 1 -5.2 -5.0 -4.8 -4.6 -4.4 -4.2 -4.0 -3.8 fig. 7, show the linear plot of ln k vs. 1/t resulting from the esterification of oleic acid for forward reaction ln k eq = -5074.5/t+16.87 1/t 0.0029 0.0030 0.0031 0.0032 ln k e q 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 fig. 8, show the linear plot of ln keq vs. 1/t resulting from the esterification of oleic acid for equilibrium reaction table 1, constant values of the esterification reaction kinetic model constant value esterification reaction k°e 2.1*10 7 (j/mole) 42189 196.3 (j/mole) 26625 1.25 0.5 1 0.5 the obtained values of rate coefficients, equilibrium constant, orders of reactants and products materials, heat of reactions and activation energy were used to simulate the results. predicted values calculated from empirical model and experimental data are shown in fig.9. kinetic study and simulation of oleic acid esterification in different type of reactors 18 ijcpe vol.14 no.2 (june 2013) -available online at: www.iasj.net real production rate, vol.%/min 0.000 0.002 0.004 0.006 0.008 0.010 p re d ic te d p ro d u c ti o n r a te , v o l. % /m in 0.000 0.002 0.004 0.006 0.008 0.010 acid fig. 9, experimental and predicted values of apparent rate constant by using suggested model of esterification of oleic acid with 6/1 ethanol/oleic molar ratio, 5% h2so4 as catalyst and temperature range from 40 to 70 ° c statistical analysis of the experimental data shows that the solution of the model (eq. 6) is proportional with the experimental data. the distribution of the experimental data around the model solution of esterification (correlation coefficient (r)) is about 0.9061, standard deviation (s) is 6.9*10 -3 , and average relative error is 1.34% in 95 % confidence level, as summarized in table 2. table 2, statistical analysis of the model statistical analysis esterification reaction correlation coefficient (r) 0.9061 standard deviation (s) 6.9 * 10 -3 average relative error 1.34% confidence level 95% simulation results simulation for the behavior of batch, plug and mixed flow reactors in different operating modes (adiabatic and isothermal) was carried out at optimum conditions (70 °c, 6/1 ethanol/oleic mol ratio, 5% h2so4 as catalyst) and the previously obtained results of kinetic models (table 1) by using reactop cascade package to predict best reaction time. fig. 10 shows the reactants and products moles with reaction time for simulated and experimental results. at the beginning of reaction the system has only liquid phase of reactant (oleic acid and ethanol with 12% water content). as time proceeds, reactant consumed, while water and ester formed. at the simulated results, the reactants consumed and products formed faster than the experimental results (as shown in table 3). from this table 3, simulated results are always higher than the experimental results which could be attributed to the effect of side reactions, which cause consumption of oleic acid to form undesirable products, such as water that reduced the formation of ester [8]. time (min) 0 20 40 60 80 100 120 r e a c ta n ts a n d p ro d u c ts m o le s 0 1 2 3 4 5 oleic (simulaltion) ester (simulation) ethanol (simulation) water (simulation) 0 20 40 60 80 100 120 0 1 2 3 4 5 oleic (calculated) ester (calculated) ethanol (calculated) water (calculated) fig. 10, show the reactants and products moles in experimental and simulation isothermal batch reactor with reaction time at best operating conditions figs. 11 and 12 show the oleic acid conversion with reaction time in batch, pfr and cstr operating in isothermal and adiabatic mode, respectively. the oleic acid conversion in isothermal batch and plug flow reactors were 0.97 after 90 min from the reaction, whereas the conversion in mixed flow reactor reached highest conversion 0.63 after 33 min and then the conversion dropped (fig. 11). fig. 12 shows the oleic acid conversion with time in batch, pfr and cstr in adiabatic mode. the ammar s. abbas and sura m. abbas -available online at: www.iasj.net ijcpe vol.14 no.2 (june 2013) 19 conversion of oleic acid were 0.84 and 0.75 after 90 min in a batch reactor and plug flow reactor, while the conversion in cstr was 0.40 after 40 min and then dropped. time (min) 0 20 40 60 80 100 120 o le ic a c id c o n v e rs io n 0.0 0.2 0.4 0.6 0.8 1.0 isothermal batch isothermal cstr isothermal pfr batch and pfr responce fig. 11, shows oleic acid conversion with time in batch, pfr and cstr reactors in isothermal mode at the best operating conditions however, it is obvious that batch and pfr is substantially better than the cstr for obtaining high conversions in both isothermal and adiabatic mode time (min) 0 20 40 60 80 100 120 o le ic a c id c o n v e rs io n 0.0 0.2 0.4 0.6 0.8 1.0 adiabatic batch adiabatic cstr adiabatic pfr fig. 12, shows the oleic acid conversion with time in batch, pfr and cstr reactors in adiabatic mode at the best operating conditions table 4 shows numerically the highest and best conversion in simulation and experimental results at different types of reactors (from figures 10 to 12). table 3, higher results at the best conditions from experimental and simulated results experimental results simulation results time moles of reactants and products time moles of reactants and products oleic ethanol ester water oleic ethanol ester water 0 1 4.44 0 1.15 0 1 4.44 0 1.15 15 0.3 3.74 0.7 1.85 15 0.22 3.64 0.79 1.94 30 0.23 3.67 0.77 1.92 30 0.08 3.51 0.92 2.07 60 0.13 3.57 0.87 2.02 60 0.03 3.47 0.96 2.12 90 0.08 3.52 0.92 2.07 90 0.02 3.46 0.97 2.12 table 4, highest conversion in simulation and experimental at operating conditions (t=70 °c, ethanol/oleic molar ratio=6/1, h2so4 =5%wt) reactor type operating mode time (min) conversion note batch isothermal 90 0.92 experimental batch isothermal 90 0.97 simulation batch adiabatic 90 0.82 simulation cstr isothermal 20 0.67 simulation cstr adiabatic 40 0.40 simulation pfr isothermal 90 0.97 simulation pfr adiabatic 90 0.74 simulation conclusion 1. the maximum conversion of oleic acid was 0.92 at 6/1 of ethanol/oleic acid mol. ratio after 90 minutes, 70° c and 5% h2so4. 2. increasing the ethanol/oleic acid molar ratio from 1 to 6 increases the conversion of oleic acid. 3. the activation energies for the suggested kinetic model were 26625 kinetic study and simulation of oleic acid esterification in different type of reactors 20 ijcpe vol.14 no.2 (june 2013) -available online at: www.iasj.net j/mole for the forward reaction and were 42189 j/mole for equilibrium constant. 4. the conversion of oleic acid in the simulated model in batch and plug flow reactors is higher than the conversion in cstr reactor in each isothermal and adiabatic mode. nomenclatures -ra = dx/dt reaction rate of oleic acid a = oleic acid , b= ethanol, c= ester , d= water k = rate coefficient of reaction. 1= forward reaction, 2= backward reaction, n and m are the reaction orders. n1 for oleic , m1 for ethanol, n2 for ester, m2 for water keq = equilibrium constant. ca, cb, cc, cd = reactants and products moles at any time. cae, cbe, cce, cde = reactants and products moles at equilibrium time. e1 = activation energy for forward reaction (j/mole) eeq = activation energy for equilibrium reaction (j/mole) ko =frequency factor ((mol) -0.74 /minute) for forward reaction koe = frequency factor for equilibrium reaction references 1. demirbas a., "energy priorities and new energy strategies", energy education science technology, vol.109, pp.16-53, 2006. 2. hodgson p.e., a book of "energy, the environment and climate change", published by world scientific publishing co. pte. ltd. isbn-13 978-1-84816-415-4, pp.19, 2010. 3. ewea (european wind energy association), "large scale integration of wind energy in the european power", issues and recommendations, brussels, 2005. 4. erec (european renewable energy council), "renewable energy scenario by 2040", erec statistics, brussels, 2006. 5. vasudevan p., sharma s., kumar a., "liquid fuel from biomass: an overview", journal of scientific & industrial research, vol.64, pp.822831, 2005. 6. yin p., chen l., wang z., qu r., liu x., ren s., "production of biodiesel by esterification of oleic acid with ethanol over organophosphonic acidfunctionalized silica", bioresource technology, vol.110, pp.258-263, 2012. 7. khan a. k., "biodiesel kinetics & catalyst development", thesis, university of queensland, 2002. 8. abbas s. m., "kinetic study and modeling of oleic acid esterification with ethanol in presence of water", thesis, university of baghdad, 2013. 9. hanh h.d., dong n., okitsu k., nishimur r., maeda y., ''biodiesel production by esterification of oleic acid with short-chain alcohols under ultrasonic irradiation condition'', renewable energy, vol.34, pp.780–783, 2008. 10. zubir m.i., chin s.y., "kinetic of modified zirconiz-catalyzed heterogeneous esterification reaction for biodiesel production", journal of applied sciences, vol.10(21), pp.2584-2589, 2010. 11. marchetti j.m., errazu a.f., "esterification of free fatty acids using sulfuric acid as catalyst in the presence of triglycerides" ,biomass and bioenergy, vol.32, pp.892-895, 2008 12. levenspiel o., a handbook of ''chemical reaction engineering'', published by john wiley and sons, third edition, pp.1472, 1999. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.20 no.3 (september 2019) 31 – 37 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name huda m. salman, email: hudamohammad20@gmail.com , name: ahmed abed mohammed, email: ahmed.abedm@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. removal of-copper ions-from aqueous solution using liquidsurfactant-membrane technique huda m. salman and ahmed abed mohammed environmental engineering department, college of engineering, university of baghdad, baghdad, iraq abstract extraction of copper (cu) from aqueous solution utilizing liquid membrane technology (lm) is more effective than precipitation method that forms sludge and must be disposed of in landfills. in this work, we have formulated a liquid surfactant membrane (lsm) that uses kerosene oil as the main diluent of lsm to remove copper ions from the aqueous waste solution through di(2-ethylhexyl) phosphoric acid d2ehpaas a carrier. this technique displays several advantages including one-stage extraction and stripping process, simple operation, low energy requirement, and. in this study, the lsm process was used to transport cu (ii) ions from the feed phase to the stripping phase, which was prepared, using h2so4. for lsm process, various parameters have been studied such as carrier concentration; treat ratio (tr), agitating speed and initial feed concentration. after finding the optimum parameters, it was possible to extract cu up to 95% from the aqueous feed phase in a single stage extraction. keywords: copper, d2ehpa, extraction, surfactant, liquid membrane received on 06/04/2019, accepted on 28/05/2019, published on 30/09/1029 https://doi.org/10.31699/ijcpe.2019.3.5 1introduction increased use of metals and chemicals in process industries has resulted in the generation of large quantities of effluent that contain high levels of toxic heavy metals and their presence poses disposal problems due to their non-degradable and persistent nature. the most toxic metals are aluminum, cobalt, chromium, iron, cadmium, nickel, zinc, copper, lead and mercury, based on world health organization (who) ‎[1]-‎[3]. the main industries that add water pollution by chromium are leather tanning, mining, electroplating, textile dyeing, coating operations, aluminum conversion, and pigments. removal of ions from their effluents has assumed of a higher importance in the recent past due to the decreasing availability of natural resources and the increasing pollution in the environment ‎[4]-‎[6]. the elimination of copper (cu) from aqueous solutions requires an efficient system for environmental reasons (toxic ions when it above who limits). there is a general concern to minimize the liquid effluents containing dangerous metals. a traditional method to remove cu from solutions is the solvent extraction method. in this technique, a well-established cu extract should be used, such as diketones or hydroxytoxics ‎[7]. lix acid (cognis) and di(2-ethylhexyl) phosphoric acid (d2ehpa), etc, the use of this carrier in the recovery of cu is well indicated elsewhere ‎[8]-‎[11]. liquid surfactant membrane (lsm) has been considered as an alternative to the solvent extraction for separating solutes, like phenols, biochemical products, and metal pollutants ‎[2], ‎[12]-‎[19]. lsm is a triple dispersion method, where a primary emulsion (water/oil or oil/water) is dispersed in a feed phase (e) to be treated. the liquid membrane comprises from three phases i) internal ii) external, and iii) organic phase. the organic phase contains a diluent, an emulsifier to stabilize the emulsion, and an extractant in the case of separation of metal ions ‎[10]. during the mixing between the feed phase (e) and emulsion (organic + internal), the solute is transported through the membrane into the stripping phase droplets and is concentrated ‎[20]. after extraction, the emulsion is separated from the raffinate phase and the demulsified of the emulsion is usually performed by applying high voltage or heat. lsm exhibit several advantages, such as re-extraction in a single stage, large specific surface area for extraction, simultaneous extraction, and the requirement of an expensive extractant in small quantities ‎[10], ‎[21], ‎[22]. the objective of this work was to check the potential of a liquid surfactant membrane, (lsm) for the extraction of copper ions from the feed solution. https://doi.org/10.31699/ijcpe.2019.3.5 h. m. salman and a. a. mohammed / iraqi journal of chemical and petroleum engineering 20,3 (2019) 31 37 23 despite, studies in this field, the study investigate various experimental parameters, like extractant concentration, treatment ratio, agitation rate, and initial feed concentration were examined, to identify the best conditions, which would give the greatest performance of the lsm. 2experimental protocols 2.1. reagents the phosphorus acid di(2-ethylhexyl) (d2ehpa) functioned as a shuttle and sorbitan monooleate (span 80 c24h44o6) was the nonionic emulsifier, both reagents were supplied by sigma-aldrich (merck, darmstadt, germany). kerosene supplied by the southern oil company (soc) (al basra-iraq) used as a diluent, while the sulphuric acid (h2so4) was the eliminating agent and was obtained from the factory producing acids and bases (babylon, iraq). copper solutions were prepared from copper nitrate (chemical, company, co., ltd. korea). 2.2. procedure the experimental work consists of four parts: preparation of the emulsion as a first step, preparation of stock solution, then running the extraction process and finally the demulsification for emulsion. fig. 1 illustrates the procedure of lsm in this paper. a. emulsion preparation mixing certain volume of kerosene, span80, and d2ehpa at homogenizer (sr30 digital homogenizer, model: 670/340 w, 10-2000ml, 3000-27000 rpm) speed of 17500 rpm to get the oil phase. the sulphuric acid (h2so4) solution as a stripping agent was added dropwise to the oil phase until the desired volume ratio of oil solution to stripping solution was obtained. the solution was stirred continuously for 10 min to obtain a stable water/oil lsm. b. feed phase preparation this phase was prepared by adding distilled water (conductivity, 1μs/m) to cu (no3)2 (solid form) to get the required concentrations (200 ppm) of copper and then adding some drops of the sulphuric acid to reach ph equal 4. c. extraction all experiments were performed at a temperature of 25±1 ° c. the prepared emulsion (error! reference source not found.) was added to a specific volume of feed solution. the production of water/oil/water double emulsions was obtained from stirring the contents by a digital stirrer (12700 rpm) for 12 min. syringe and filter syringe was used to draw external solution (e) and then analyzed it by aas (atomic absorption spectrophotometry). the resulted solution was allowed to separate to an emulsion (water/oil) and an external solution (e) by gravity in a separation funnel for 24 hours. after twophase separation, the external phase was drawn and the concentration of cu in the internal phase was analyzed using aas (atomic absorbtion spectrophotometer). the cu(ii) ions remain in membrane phase can be calculated by mass balance. to know the significant variables relating to the extraction of cu, the extractant concentration, initial cu concentration, treat ratio (tr), and stirring speed were varied to observe their effects on cu extraction. d. demulsification of the emulsion after the extraction experiment, the loaded emulsion was broken using a hot plate magnetic stirrer (70 °c for 43 min) into the internal cu concentrated phase and the organic phase. the internal phase (i) was analyzed and after that determining cu concentration. fig. 1. lsm technique,: (1) droplets, (2) organic phase, (3) globules, (4) emulsifier and (5) internal phase and cu 2.3. extraction mechanism in the elm system the prepared emulsion (sec. ‎2.2 a) was transferred to the external phase containing a certain concentration of copper ions at ph 4 (adding some drops of 0.2 m h2so4). a digital mixer was utilized to agitate the solution for 0–12 minutes. the extraction and stripping reactions of the copper ions are elucidated in equation 1 and 2. where: rh refers to the protonated form of an extracting (d2ehpa in this paper) ‎[23]. d2ehpa structure is revealed in fig. 2 ‎[24], ‎[25]. h. m. salman and a. a. mohammed / iraqi journal of chemical and petroleum engineering 20,3 (2019) 31 37 22 fig. 2. depicts the structure of d2ehpa extraction reaction of the copper ions:    ( ) ( ) 2 2 2 22s l cu rh pbr rh h    (1) stripping reaction of the copper ions:    ( ) ( ) 22 2 2 22 s l cur rh h cu rh    (2) equation (1) denotes the reaction at the membrane (o) – external (e) interface, while equation (2) shows the reaction where the copper ions are stripped at the oil (o) – internal (w) interface. the cu (ii) ions transfer by an extracting from the external to the internal phase is explained in fig. 3. the extraction percentage (e%) is found based on the equation (3) : c c outine% = ×100 % c in (3) where cin is the initial copper concentration in the external phase, and cout is the copper ion concentration post the extraction stage. fig. 3. depicts the transfer mechanism of lsm 3results and discussion 3.1. effect of changes in carrier concentration on copper removal efficiency this paragraph presented in fig. 4 as expected, as soon as the mixing began, the first 0.5 min the extraction efficiency increased due to the carrier's effectiveness in carrying the copper ions as well as increasing the shuttle d2ehpa concentration from 6% 8% (v/v) provides only 2% increase in the quantity extracted using lsm. at 10% d2ehpa, the % e slightly decreased. it should be noted that under optimum conditions in the copper extraction from nitrate solution it was observed that d2ehpa concentration in the membrane phase in the range of 2% (v/v) to 4% (v/v) decreased the rate of extraction of copper as observed by ‎[2], ‎[23]. from an economic point of view, an enhancement of 2% is very low, so 6% d2ehpa is applied in the experiments. fig. 4. effect of d2ehpa concentration on the cu extraction at optimal conditions, using lsm (o/i=1/1, span 80=4 v/v%, h2so4=0.5 m, feed concentration≈ 200 mg/l, ph=4, tr=1:10, mixing speed=250 rpm) 3.2. effect of changes of stirring speed on the copper removal efficiency another parameter affecting extraction to a large extent was found to be stirring speed, and it has been studied in the range 150 to 550 rpm using lsm1 and shown in fig. 5. as the stirring speed increased from 150 to 250 rpm, the removal of copper increased from 82% to 94.7% in 11 min time using lsm. this was due to the small size of the globules (ssg) that were formed by shear force from the impellers of the stirrer, which provided more interfacial surface area for effective mass transfer. above 11 min, no copper was detected in the external phase due to membrane breakage. however, as the stirring rate was increased to 300 rpm, more shear was introduced into the emulsion and external phase, which promotes emulsion breakage. for lower agitating speed, the interfacial contact area and mass transfer between the external phase and emulsion decreased due to the larger size of the emulsion. a 250 rpm was suitable for satisfactory extraction percentage. after 250-rpm extraction, percentage starts to decline. further increase in the mixing speed resulted in a break of liquid surfactant membranes leading to an outflow of extracted lead into the external phase. this is because of a higher mixer speed which beyond limits generally results in higher water transport into the inner strip phase causing the membrane to swell ‎[26], ‎[27]. therefore, 250 rpm was chosen as the optimum mixing speed for extraction of cu (ii). h. m. salman and a. a. mohammed / iraqi journal of chemical and petroleum engineering 20,3 (2019) 31 37 23 fig. 5. effect, of stirring speed on a rate of copper extraction using lsm 3.3. effect of changes of treat ratio (tr) on the copper removal efficiency the treat ratio in an lsm extraction is the ratio of the emulsion phase to feed phase. increasing tr generally leads to, an increase in the loading capacity, and the rate of, extraction. this case happened due to existence increment in emulsion volume and correspondingly an increase in d2ehpa, and h2so4 ‎[28], ‎[29]. fig. 6 illustrates the effect of tr on the copper extraction from copper nitrate solutions using lsm. as tr increased there was an increase in the efficiency of, this occurs when this ratio increased from 1:15 to 1:10. this pattern could be recognized from a possible increase in globule size distribution due to the increased hold-up of the emulsion. sengupta et al. (2006) have noted a strong decline in the extraction percentage of silver ions when tr was increased from, 1:6 to 1:4 due to increased globule-size distribution at larger emulsion hold-ups. fig. 6. effect of (tr) on the cu-extraction by lsm the formation of lg (larger-globules) reduces the areas of the outer surface and will increase the effective-length of the diffusion pathways among the globule, causing a low rate of cu removal. treat ratios of 1:15, 1:10 and 1:5 indicate a considerable increase in extraction capability at what time tr increased from 1:15 to 1:10, due to, the increase inemulsion retention, the distribution of the size of globules tended to change towards lg with a consequent reduction in the rates. 3.4. effect of changes of initial copper concentration on copper removal efficiency the effect of initial cu (ii) ions concentrations in the feed, on the rate of copper extraction, was investigated using-emulsions having o/i=1/1, span80 =4 v/v % of the organic phase and h2so4=0.5 m, d2ehpa= 6% (v/v). the initial (ph) and (tr) were kept at 4 and 1:10 respectively. extraction results are displayed in fig. 7 that is a plot of the change in copper concentration in the feed phase with time. the pattern of copper loading in lsm along with a quantitative assessment of the amount of copper stripped in the internal-stripping phase of the emulsion, after a 12 min contact between the feedand the lsm, for initialfeed concentration variations, is presented in fig. 8. fig. 7. effect of initial-feed concentration on rate of copper extraction using lsm (o/i=1/1, span 80 =,4 v/v%, h2so4=,0.5 m, d2ehpa=6%, feed concentration≈ 200 mg/l, ph=4, tr=1:10, mixing speed=250 rpm). (cu ie, initial-concentration of copper, in the external phase) it was observed that as the initial-feed concentration increased, the extent of copper-extraction-into lsm also increased. when cu loading was low most of the cu extracted in the membranes got stripped in the internal phase of the membranes. however, at high copper loadings, the amount of copper stripped in the internal phase of the lsms did not increase substantially; hence most of the copper extracted by the lsms was retained in the membrane-phase‎[4], ‎[21], ‎[22]. h. m. salman and a. a. mohammed / iraqi journal of chemical and petroleum engineering 20,3 (2019) 31 37 24 fig. 8. copper extraction, stripping patterns in lsm (int., internal phase; roil, retained in the oil phase; fext, final concentration in the external phase the low percentage of cu stripping could be recognized from the slow stripping kinetics as well as the diffusional effects that play an important role in further slowing down the stripping rates. high values of cuie (initial copper concentration) lead to greater copper loadings in the lsms causing, quick-saturation of the peripheral internal-phase droplets in the emulsion necessitates deeper-penetration of the cu– d2ehpa complex within the emulsion-globules to get stripped. 4conclusions extraction of copper cu (ii) from an aqueous phase was studied utilizing a liquid surfactant membrane (lsm). the membrane was composed of d2ehpa dissolved in kerosene and span80 as a solvent as an emulsifier respectively. sulfuric acid (h2so4) was utilized as the strippingsolution. the optimum conditions for cu extraction are: (a) 6-8% (v/v) d2ehpa concentration, (b) 4% (v/v) span80 concentration, (c) 0.5 m h2so4 concentration in the internal-phase, (d) 1:1 the ratio of internal-phase to membranephase, (e) acidity in external-phase is 4 ; (f) external phase volume to membrane volume 1/10, (g) extraction time, 11 minutes; and (h) agitating speed, 250 rpm. the results also showed many parameters, stirring speed, the d2ehpa concentration, feed concentration and treating ratio, are very important in the extraction of cu, (2) the extraction efficiency (e) of cu is 95% at 11 min., (3) at higher agitating speed of the water/oil/water emulsion produces small emulsion droplets, consequently increases the interface area of the carrier/cu reaction. however, it is necessary this paper considered a maximum limit (250 rpm) to increase the extraction efficiency, (4) the results showed that the lsm method is a beneficial process to remove cu from aqueous solution. references [1] h.a. hegazi, removal of heavy metals from wastewater using agricultural and industrial wastes as adsorbents, hbrc journal 9 (2013) 276-282. [2] a.a. mohammed, h.m. selman, liquid surfactant membrane for lead separation from aqueous solution: studies on emulsion stability and extraction efficiency, journal of environmental chemical engineering 6 (2018) 6923-6930. [3] a. h. algureiri and y. r. abdulmajeed, ―removal of heavy metals from industrial wastewater by using ro membrane‖, ijcpe, vol. 17, no. 4, pp. 125-136, dec. 2016. [4] d. lu, y. chang, w. wang, f. xie, e. asselin, d. dreisinger, copper and cyanide extraction with emulsion liquid membrane with lix 7950 as the mobile carrier: part 1, emulsion stability, metals 5 (2015) 2034-2047. [5] m. hasan, y. selim, k. mohamed, removal of chromium from aqueous waste solution using liquid emulsion membrane, journal of hazardous materials 168 (2009) 1537-1541. [6] a.m. hochhauser, e. cussler, concentrating chromium with liquid surfactant membranes, aiche symposium series, american institute of chemical engineers, 1975, pp. 136-142. [7] j. rydberg, c. musikas, g.r. choppin, principles and practices of solvent extraction, m. dekker new york1992. [8] k. kongolo, m. mwema, a. banza, e. gock, cobalt and zinc recovery from copper sulphate solution by solvent extraction, minerals engineering 16 (2003) 1371-1374. [9] s.-y.b. hu, j.m. wiencek, copper—lix 84 extraction equilibrium, separation science and technology 35 (2000) 469-481. [10] s. abdel-halim, a. shehata, m. el-shahat, removal of lead ions from industrial waste water by different types of natural materials, water research 37 (2003) 1678-1683. [11] e.a. fouad, zinc and copper separation through an emulsion liquid membrane containing di‐(2‐ ethylhexyl) phosphoric acid as a carrier, chemical engineering & technology: industrial chemistry‐ plant equipment‐process engineering‐biotechnology 31 (2008) 370-376. [12] p.f. correia, j.m. de carvalho, recovery of 2chlorophenol from aqueous solutions by emulsion liquid membranes: batch experimental studies and modelling, journal of membrane science 179 (2000) 175-183. [13] a.a. mohammed, h.m. selman, extraction of lead ions from aqueous solution by co-stabilization mechanisms of magnetic fe2o3 particles and nonionic surfactants in emulsion liquid membrane, https://www.sciencedirect.com/science/article/pii/s1687404813000552 https://www.sciencedirect.com/science/article/pii/s1687404813000552 https://www.sciencedirect.com/science/article/pii/s1687404813000552 https://www.sciencedirect.com/science/article/pii/s2213343718306274 https://www.sciencedirect.com/science/article/pii/s2213343718306274 https://www.sciencedirect.com/science/article/pii/s2213343718306274 https://www.sciencedirect.com/science/article/pii/s2213343718306274 https://www.sciencedirect.com/science/article/pii/s2213343718306274 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/239 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/239 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/239 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/239 https://www.mdpi.com/2075-4701/5/4/2034 https://www.mdpi.com/2075-4701/5/4/2034 https://www.mdpi.com/2075-4701/5/4/2034 https://www.mdpi.com/2075-4701/5/4/2034 https://www.mdpi.com/2075-4701/5/4/2034 https://www.sciencedirect.com/science/article/pii/s0304389409004427 https://www.sciencedirect.com/science/article/pii/s0304389409004427 https://www.sciencedirect.com/science/article/pii/s0304389409004427 https://www.sciencedirect.com/science/article/pii/s0304389409004427 https://experts.umn.edu/en/publications/concentrating-chromium-with-liquid-surfactant-membranes https://experts.umn.edu/en/publications/concentrating-chromium-with-liquid-surfactant-membranes https://experts.umn.edu/en/publications/concentrating-chromium-with-liquid-surfactant-membranes https://experts.umn.edu/en/publications/concentrating-chromium-with-liquid-surfactant-membranes https://experts.umn.edu/en/publications/concentrating-chromium-with-liquid-surfactant-membranes https://www.sciencedirect.com/science/article/abs/pii/s0892687503002851 https://www.sciencedirect.com/science/article/abs/pii/s0892687503002851 https://www.sciencedirect.com/science/article/abs/pii/s0892687503002851 https://www.sciencedirect.com/science/article/abs/pii/s0892687503002851 https://www.tandfonline.com/doi/abs/10.1081/ss-100100170 https://www.tandfonline.com/doi/abs/10.1081/ss-100100170 https://www.tandfonline.com/doi/abs/10.1081/ss-100100170 https://www.sciencedirect.com/science/article/abs/pii/s0043135402005547 https://www.sciencedirect.com/science/article/abs/pii/s0043135402005547 https://www.sciencedirect.com/science/article/abs/pii/s0043135402005547 https://www.sciencedirect.com/science/article/abs/pii/s0043135402005547 https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.200700433 https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.200700433 https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.200700433 https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.200700433 https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.200700433 https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.200700433 https://www.sciencedirect.com/science/article/pii/s037673880000497x https://www.sciencedirect.com/science/article/pii/s037673880000497x https://www.sciencedirect.com/science/article/pii/s037673880000497x https://www.sciencedirect.com/science/article/pii/s037673880000497x https://www.sciencedirect.com/science/article/pii/s037673880000497x https://www.sciencedirect.com/science/article/abs/pii/s0927775719301050 https://www.sciencedirect.com/science/article/abs/pii/s0927775719301050 https://www.sciencedirect.com/science/article/abs/pii/s0927775719301050 https://www.sciencedirect.com/science/article/abs/pii/s0927775719301050 h. m. salman and a. a. mohammed / iraqi journal of chemical and petroleum engineering 20,3 (2019) 31 37 25 colloids and surfaces a: physicochemical and engineering aspects (2019). [14] e. fouad, f. ahmad, k. abdelrahman, optimization of emulsion liquid membrane for lead separation from aqueous solutions, engineering, technology & applied science research 7 (2017) 2068-2072. [15] l. zeng, w. wang, w. chen, c. bukirwa, y. yang, experimental and modeling of nickel removal from sulfate solutions by emulsion liquid membrane using pc 88a, desalination and water treatment 57 (2016) 11184-11194. [16] y.s. ng, n.s. jayakumar, m.a. hashim, performance evaluation of organic emulsion liquid membrane on phenol removal, journal of hazardous materials 184 (2010) 255-260. [17] p.f. correia, j.m. de carvalho, a comparison of models for 2-chlorophenol recovery from aqueous solutions by emulsion liquid membranes, chemical engineering science 56 (2001) 5317-5325. [18] i. diaconu, r. gîrdea, c. cristea, g. nechifor, e. ruse, e.e. totu, removal and recovery of some phenolic pollutants using liquid membranes, romanian biotechnological letters 15 (2010) 57025708. [19] h.e. mahmoud, a.a. al-hemiri, minimization of toxic ions in waste water using emulsion liquid membrane technique, iraqi journal of chemical and petroleum engineering 11 (2010) 11-19. [20] o. zing-yi, n. othman, m. mohamad, r. rashid, removal performance of lignin compound from simulated pulping wastewater using emulsion liquid membrane process, international journal of global warming 6 (2014) 270-283. [21] b. sengupta, m.s. bhakhar, r. sengupta, extraction of copper from ammoniacal solutions into emulsion liquid membranes using lix 84 i®, hydrometallurgy 89 (2007) 311-318. [22] a. rouhollahi, e. zolfonoun, m. salavatiniasari, effect of anionic surfactant on transport of copper (ii) through liquid membrane containing a new synthesis schiff base, separation and purification technology 54 (2007) 28-33. [23] z. ren, w. zhang, h. meng, y. liu, y. dai, extraction equilibria of copper (ii) with d2ehpa in kerosene from aqueous solutions in acetate buffer media, journal of chemical & engineering data 52 (2007) 438-441. [24] j. he, y. li, x. xue, h. ru, x. huang, h. yang, extraction of ce (iv) from sulphuric acid solution by emulsion liquid membrane using d2ehpa as carrier, rsc advances 5 (2015) 74961-74972. [25] m. irannajad, z. afzali, h.k. haghighi, solvent extraction of copper using tbp, d2ehpa and mibk, russian journal of non-ferrous metals 59 (2018) 605-611. [26] r.a. kumbasar, extraction and concentration of cobalt from acidic leach solutions containing co–ni by emulsion liquid membrane using toa as extractant, journal of industrial and engineering chemistry 16 (2010) 448-454. [27] y.r. abdulmajeed, c.k. haweel, q.j. slaiman, removal of heavy metals ions from aqueous solutions using biosorption onto bamboo, iraqi journal of chemical and petroleum engineering 11 (2010) 23-32. [28] a. kusumastuti, r. syamwil, s. anis, emulsion liquid membrane for textile dye removal: stability study, aip conference proceedings, aip publishing, 2017, pp. 020026. [29] m. perumal, b. soundarajan, n. thazhathuveettil vengara, extraction of cr (vi) by pickering emulsion liquid membrane using amphiphilic silica nanowires (asnws) as a surfactant, journal of dispersion science and technology (2018) 1-10. https://www.sciencedirect.com/science/article/abs/pii/s0927775719301050 https://www.sciencedirect.com/science/article/abs/pii/s0927775719301050 https://www.etasr.com/index.php/etasr/article/view/1390 https://www.etasr.com/index.php/etasr/article/view/1390 https://www.etasr.com/index.php/etasr/article/view/1390 https://www.etasr.com/index.php/etasr/article/view/1390 https://www.etasr.com/index.php/etasr/article/view/1390 https://www.tandfonline.com/doi/abs/10.1080/19443994.2015.1043951 https://www.tandfonline.com/doi/abs/10.1080/19443994.2015.1043951 https://www.tandfonline.com/doi/abs/10.1080/19443994.2015.1043951 https://www.tandfonline.com/doi/abs/10.1080/19443994.2015.1043951 https://www.tandfonline.com/doi/abs/10.1080/19443994.2015.1043951 https://www.sciencedirect.com/science/article/pii/s0304389410010460 https://www.sciencedirect.com/science/article/pii/s0304389410010460 https://www.sciencedirect.com/science/article/pii/s0304389410010460 https://www.sciencedirect.com/science/article/pii/s0304389410010460 https://www.sciencedirect.com/science/article/pii/s0009250901002408 https://www.sciencedirect.com/science/article/pii/s0009250901002408 https://www.sciencedirect.com/science/article/pii/s0009250901002408 https://www.sciencedirect.com/science/article/pii/s0009250901002408 https://e-repository.org/rbl/vol.15/iss.6/5.pdf https://e-repository.org/rbl/vol.15/iss.6/5.pdf https://e-repository.org/rbl/vol.15/iss.6/5.pdf https://e-repository.org/rbl/vol.15/iss.6/5.pdf https://e-repository.org/rbl/vol.15/iss.6/5.pdf http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/360 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/360 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/360 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/360 https://www.inderscienceonline.com/doi/abs/10.1504/ijgw.2014.061021 https://www.inderscienceonline.com/doi/abs/10.1504/ijgw.2014.061021 https://www.inderscienceonline.com/doi/abs/10.1504/ijgw.2014.061021 https://www.inderscienceonline.com/doi/abs/10.1504/ijgw.2014.061021 https://www.inderscienceonline.com/doi/abs/10.1504/ijgw.2014.061021 https://www.sciencedirect.com/science/article/abs/pii/s0304386x07001727 https://www.sciencedirect.com/science/article/abs/pii/s0304386x07001727 https://www.sciencedirect.com/science/article/abs/pii/s0304386x07001727 https://www.sciencedirect.com/science/article/abs/pii/s0304386x07001727 https://www.sciencedirect.com/science/article/pii/s1383586606002607 https://www.sciencedirect.com/science/article/pii/s1383586606002607 https://www.sciencedirect.com/science/article/pii/s1383586606002607 https://www.sciencedirect.com/science/article/pii/s1383586606002607 https://www.sciencedirect.com/science/article/pii/s1383586606002607 https://pubs.acs.org/doi/abs/10.1021/je060370o https://pubs.acs.org/doi/abs/10.1021/je060370o https://pubs.acs.org/doi/abs/10.1021/je060370o https://pubs.acs.org/doi/abs/10.1021/je060370o https://pubs.acs.org/doi/abs/10.1021/je060370o https://pubs.rsc.org/en/content/articlehtml/2015/ra/c5ra11851d https://pubs.rsc.org/en/content/articlehtml/2015/ra/c5ra11851d https://pubs.rsc.org/en/content/articlehtml/2015/ra/c5ra11851d https://pubs.rsc.org/en/content/articlehtml/2015/ra/c5ra11851d https://link.springer.com/article/10.3103/s1067821218060068 https://link.springer.com/article/10.3103/s1067821218060068 https://link.springer.com/article/10.3103/s1067821218060068 https://link.springer.com/article/10.3103/s1067821218060068 https://www.sciencedirect.com/science/article/pii/s1226086x10000766 https://www.sciencedirect.com/science/article/pii/s1226086x10000766 https://www.sciencedirect.com/science/article/pii/s1226086x10000766 https://www.sciencedirect.com/science/article/pii/s1226086x10000766 https://www.sciencedirect.com/science/article/pii/s1226086x10000766 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/381 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/381 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/381 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/381 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/381 https://www.tandfonline.com/doi/abs/10.1080/01932691.2018.1496829 https://www.tandfonline.com/doi/abs/10.1080/01932691.2018.1496829 https://www.tandfonline.com/doi/abs/10.1080/01932691.2018.1496829 https://www.tandfonline.com/doi/abs/10.1080/01932691.2018.1496829 https://www.tandfonline.com/doi/abs/10.1080/01932691.2018.1496829 https://www.tandfonline.com/doi/abs/10.1080/01932691.2018.1496829 h. m. salman and a. a. mohammed / iraqi journal of chemical and petroleum engineering 20,3 (2019) 31 37 26 إزالة أيونات النحاس من محلول مائي باستخدام تقنية الغشاء السطحي السائل هدى محمد سلمان و احمد عبد محمد العراق, بغدادقسم الهندسة البيئية, كمية الهندسة, جامعة بغداد, الخالصة أكثر فعالية من الطرق (lm) المحمول المائي باستخدام تقنية الغشاء السائلمن (cu) يعد استخراج النحاس التقميدية التي تنتج الحمأة ويجب ان يتم التخمص منها في مدافن النفايات. في هذا العمل ، قمنا بتكوين غشاء حمول إلزالة أيونات النحاس من الممغشاء يستخدم زيت الكيروسين كمخفف رئيسي لـ (lsm) سطحي سائل كناقل(. يعرض هذا – d2ehpa ) (إيثيل هكسيل 2المائية من خالل حامض الفسفوريك ثنائي اإليثيل ) األسموب العديد من المزايا مثل االنتقائية العالية، التشغيل البسيط، متطمبات الطاقة المنخفضة، عممية االستخراج ة لنقل النحاس من مرحمة المحمول الخارجية إلى مرحمة والتجريد عمى مرحمة واحدة. وقد تم استخدام هذه الطريق االنتزاع، التي تم إعدادها باستخدام حامض الكبريتيك، تمت دراسة العوامل المختمفة مثل تركيز الناقل ونسبة وسرعة التحريك وتركيز النحاس األولي. بعد الحصول عمى العوامل المثمى، كان نسبة استخراج (tr) المعالجة ممغم لكل لتر. 222٪ من المحمول المائي بتركيز اولي 59النحاس .، استخراج، المثبت، الغشاء السائل : النحاس، الناقلالدالةكممات ijcpe vol.11 no. 1 (march 2010) iraqi journal of chemical and petroleum engineering vol.11 no.1 (march 2010) 29-45 issn: 1997-4884 numerical study of the mixed convection flow over a square cylinder sajida lafta ghashim jassim mechanical engineering department college of engineering university of baghdad – iraq abstract in this work, a numerical study is performed to predict the solution of two – dimensional, steady and laminar mixed convection flow over a square cylinder placed symmetrically in a vertical parallel plate. a finite difference method is employed to solve the governing differential equations, continuity, momentum, and energy equation balances. the solution is obtained for stream function, vorticity and temperature as dependent variables by iterative technique known as successive over relaxation. the flow and temperature patterns are obtained for reynolds number and grashof number at (re= -50,50,100,-100) (positive or negative value refers to aidding or opposing buoyancy , +1 assisting flow, -1 opposing flow) and (102 to 105) , respectively. the results displaced that the recirculation length above the cylinder increases with the increase in gr number and the average nu number is the highest at the lower surface of the cylinder, while is the lowest at the top of the cylinder surface. a comparison between the obtained results and the published computational studies has been made and it showed a good agreement. keywords: cfd, square cylinder; mixed convection; blockage ratio; nusselt number introduction the combined forced and free convection heat transfer from cylinders (of circular or square cross-section) has numerous industrial applications such as cooling towers, oil and gas pipelines, tubular and compact heat exchangers, cooling of electronic components, flow dividers in polymer processing applications and so on. the analysis of mixed convection is more complicated than that of the pure forced or free convection alone. most of the important work on mixed convection past bluff bodies deals with the heat transfer around a heated circular cylinder. an account of many of the experimental results and correlations for forced convection heat transfer from a circular cylinder has been given by morgan [1]. there are, however, comparatively fewer numerical studies on this topic than for isothermal flow past a circular cylinder. dennis et al. [2] obtained the numerical solution for the steady laminar forced convection from a circular cylinder. karniadakis [3] used the spectral element method to obtain forced-convection heat transfer from an isolated circular cylinder in cross flow, for both steady and unsteady periodic flow, for re≥200. yang et al. [4] obtained a numerical solution for the transient laminar forced convection from a circular cylinder at re=100, 200, and 500. saha [5] studied the effects of the heat transfer and flow analysis of free convective flow past a square cylinder placed symmetrically in a vertical parallel plate channel. the flow is found to be unstable when the grashof number crosses the critical value of 3.0x104. farouk and güceri [6] computed the mixed and free convection from an isothermal circular cylinder in a twodimensional vertical channel with adiabatic walls in the steady flow regime. biswas et al. [7] investigated the cross-flow of air over a horizontal square cylinder confined in a channel (isothermal walls) of the blockage ratio of 0.25 for a range of values of the reynolds and university of baghdad college of engineering iraqi journal of chemical and petroleum engineering numerical study of the mixed convection flow over a square cylinder 30 ijcpe vol.11 no.1 (march 2010) grashof numbers. they reported the maxima and minima in the velocity and temperature profiles close to the bottom walls of the channel, respectively. they also reported that the periodicity of flow and asymmetry of the wake can occur at lower reynolds numbers than that in pure forced convection. turki et al. [8] have numerically investigated the mixed convection from a horizontal square cylinder to air for 120≥re≥200 for ri up to 0.1 for a blockage ratio of 0.25. the value of the critical reynolds number (onset of periodic flow) decreases while the strouhal number increases with the increasing richardson number. they also proposed correlations for nusselt number at different values of the richardson number (ri=0, 0.05 and 0.1). atul sharma and eswaran [9] studied the effects of the flow structure and heat transfer characteristics of an isolated square cylinder in cross flow numerically for both steady and unsteady periodic laminar flow in the two-dimensional regime, for reynolds numbers of 1 to 160 and a prandtl number of 0.7. the effect of vortex shedding on the isotherm patterns and heat transfer from the cylinder is discussed. heat transfer correlations between nusselt number and reynolds number are presented for uniform heat flux and constant cylinder temperature boundary conditions. the current study as shown in figure(1) is focused on the effect of aiding and opposing buoyancy over a square cylinder, placed symmetrically in a vertical parallel plates. we focused on the calculation of mean and average nusselt number along the position on the surfaces of cylinder. proplem description the problem studied in this paper is a two dimensional laminar buoyancy flow and heat transfer in flow past a square cylinder placed symmetrically in a vertical parallel plate see figure (1). the considered grashof number ranged from (10 2 – 10 5 ), the working fluid was air with (pr=0.71).a square cylinder with side b, the dimensionless length scale, is heated or cooled to a constant temperature tw. it is exposed to a constant freestream upward velocity and temperature represented by u∞ and t∞, respectively.lu the dimensionless distance between the top surface of the cylinder and exit plane, ld the dimensionless distance between the inlet plane and the bottom surface of the cylinder and l the total dimensionless height of the computational domain. figure (1) computational domain for the flow around a square cylinder and the associated parameters. mathematical model the steady, conservative, dimensionless from of the navierstockes equations in two dimensions for the incompressible laminar flow is given as follows [5]: continuity: 0      y v x u (1) xmomentum:                           2 2 2 2 re 1 y u x u x p vu y uu x (2) ymomentum:      22 2 2 2 rere 1 gr y v x v y p vv y uv x                        (3) energy:                    2 2 2 2 rep r 1 yxy v x u  (4) with   u u u ,   u v v , b x x  b y y  , 2   u p p  ,    tt tt w  sajida lafta ghashim jassim ijcpe vol.11 no.1 (march 2010) 31 vorticity transport and stream function:                       2 2 2 2 2 re 1 re )()( yxx gr v y u x   (5) the only nonzero component of the vorticity is: y u x v       (6) from the definition of stream function which verifies the continuity equation, vertical and horizontal components can be written as: x v     (7) y u     (8) by substituting equation (7) and (8) into equation (6) to obtain the following stream equation:    2 2 2 2 2        yx (9) boundary conditions solid surface of the cylinder u=0, v=0, θ=1 left and right walls (boundary) u=0, v=0, 0   y  bottom boundary (inlet) v=0, u=1, θ=0 top boundary (out let) 0   y  numerical solution the numerical analysis of steady state convection problem may be based on a system of heat convection equation of the form [10]:         2 2 2 2 yx (10) x gr v yy u xx                              2 rere 1 re 1 (11) 0 repr 1 repr 1                           v yy u xx (12) the numerical solution of this system may be obtained by solving its difference system with some available iteration procedure. consider the second order conservative, monotonic finite difference scheme approximating system of equations (10), (11) and (12). the scheme has been used for steady convective problems involving wide ranges of process parameters and has given good results. it employes the integrointerpolation method. a system of difference equations is obtained by integrating the original system (10), (11) and (12) over a mesh di ( xi-1/2 ≤ x ≤ xi+1/2 , yi-1/2 ≤ y ≤ yi+1/2 ) shown in figure ( 2 ) [10]. following is the procedure in [10], the governing finite difference equations for (, , and ) can be written in the standard five point formula form. these finite difference equations which subject to appropriate boundary conditions are solved by an iterative method known as successive substitution. if ( s,s, and s) denote functional values at the end of sth iteration, the value of ( ,, and ) at (s+1)th iteration level are calculated from the following expressions: )()1( 1 1,, 1 ,1,1, 1 ,       s ji s ji s ji s ji s ji s ji dcba a f f      (13)                        1 ,1 1 ,12 1 1,1, 1 ,1,1 1 , 1 , re 5.0)()1( s ji s ji s ji s ji s ji s ji s ji s ji gr dcba a f f      (14) )( 4 )1( 1 1, 21 1,1, 1 ,1,1 1 , 1 ,         s ji s ji s ji s ji s ji s ji s ji hdcba f f     (15) numerical study of the mixed convection flow over a square cylinder 32 ijcpe vol.11 no.1 (march 2010) where (s) is the iteration number, and  ff , and f are the relaxation parameters which depend on the mesh size and fluid mechanical parameters. for all cases in present study, an overrelaxation parameters  ff , and f equal to 0.7, 0.5, and 0.7 [10]. a converged solution was defined as one that meets the following criterion for all dependent variables. 4 ),( 11 ),( 10/)(   ji sss jierror  (16) figure (2) the mesh di numerical calculation of the vorticity values on the walls 2 *3 ,1 2 1,, , wijiji wi h        vorticity equation on vertical wall 2 *3 ,1 2 ,1, 1, jijiji ji h         vorticity equation on horizontal wall 2 *3 1, 2 1,, 1,       jijiji ji h   calculation of average nusselt number the average nusselt number at the wall is calculated from the temperature gradient at the wall by the following form [10]: k hb nu  where: n t ktth w     )( then )(      tt n t b nu w the above equation can be written in dimensionless form as follows: n nu jl     )( using the third order polynominal function (θ) , the final form of ( )( jl nu ) equation is [ 10 ]:  jijijijl h nu ,2,1,)( 43 2 1    calculation of mean nusselt number the mean nusselt number can be calculated from equation below[ 10 ]:  b nudx b nu 0 1 the integration can be evaluated by using numerical integration (simpsions rule) as below [10]:           )( 2 )2( 1 )1()1( 24 3 nl j jl j jll nunununu h nu where: j1= 2,4,6,…….., y-1 j2= 3,5,7,…….., y-2 sajida lafta ghashim jassim ijcpe vol.11 no.1 (march 2010) 33 results and discussion in this work, the results were obtained for heat transfer by laminar mixed convection flow over a square cylinder. the results obtained using the numerical solution, computer program (fortran 90) and tecplot program. figures (3-6) show the distribution of the average nusselt number versus position along the cylinder surface (for different gr values). has been shown for the left half of the square cylinder (the other half is symmetric), for various gr number the figures show that the nusselt number along the left half of the bottom face (ab) of the cylinder increases .for the left surface (bc), it has a minimum, this is due to turning. in the separation region (cd), there is a local minimum. when the buoyancy force is in the direction of the flow (buoyancy aided), it can be seen that the average nusselt number increases with the increase of gr number, an opposite observations are obtained for the case, when the buoyancy force is opposite of the flow direction (buoyancy opposed). figures (7-10) to (10-13) show the isotherms and streamlines contour for different gr number values in the vicinity of the cylinder, under the influence of buoyancy. the mechanism of the flow occurs when the fluid near the hot wall is heated causing the density to be decreased and the fluid will be start to move towards the cold wall. it can be seen that the values of isotherms at the cylinder surface increased when gr number increased. when decreasing (gr/re 2 ) < 0 , increases the width of the wake, and the separation point moves from the downstream corners to the upstream end corners, due to the increased negative buoyancy force of the colder air. it also reduces the velocity of the fluid in the wake region, opposite observations are obtained when (gr/re 2 ) > 0. so to discern the effect of the recirculation region on the isotherms and heat transfer from the cylinder. the maximum crowding of the isotherms is seen on the bottom face, indicating the highest nusselt number, as compared to other surfaces of the cylinder, since the thermal boundary layer growth starts from this face. figure (15) shows the variation of mean nusselt number versus the gr number with different values of re number. this figures show that when the buoyancy force is in the direction of the flow the value of mean nusselt number increase with increased re number, but an opposite effect was found for the case when the buoyancy force is opposite of the flow direction (buoyancy opposed). figure (16) shows average nusselt number versus position along the cylinder surface at different gr values (refernce[5] ) . it has been seen that the nusselt number is at its highest at the lower surface of the cylinder. on the side walls it is lower because fluid from bottom of the cylinder becomes heated and flows past the cylinder. the nusselt number is the lowest at the top of the cylinder surface because of the low velocity fluid that forms the vortices (bubbles). the present numerical results are compared with the published results as shown in figure (17). from the figure, the comparison indicated a good agreement. conclusions 1. the strength of the re-circulating vortices is increased with the increase of gr number. 2. the average nusselt number is the highest at the lower surface of the cylinder, while is the lowest at the top of the cylinder surface because of the low velocity fluid. 3. the maximum crowding of the isotherms is seen on the bottom face, indicating the highest nusselt number, as compared to other surfaces of the cylinder, since the thermal boundary layer growth starts from this face. nomenclature symbol description unit b width of the square cylinder p c specific heat j/kg.k g gravitational acceleration m/sec 2 gr grashof number ( 2 3 )(      ttbg gr w ) h dimensionless width of the computational domain k thermal conductivity of fluid w/m.k lu dimensionless distance between the top surface of the cylinder and exit plane ld dimensionless distance between the inlet plane and the bottom surface of the cylinder l dimensionless height of the computational domain n cylinder surface normal direction l nu average nessult number nu mean nessult number p air pressure n/m2 p dimensionless air pressure (   upp  ) numerical study of the mixed convection flow over a square cylinder 34 ijcpe vol.11 no.1 (march 2010) pr prandtl number ( kc p /pr  ) re reynolds number (  /re bu   ) ri rechardson number (ri= gr/re 2 ) t temperature k  t free stream temperature k u dimensionless velocity component in x-direction u∞ free stream velocity m/s v dimensionless velocity component in y-direction x horizontal axis m x dimensionless horizontal axis )( bxx  y vertical axis m y dimensionless vertical axis )( byy   dimensionless temperature (     tt tt w  )   dynamic viscosity of the fluid pa.s   kinematic viscosity of the fluid m 2 /sec   density of the fluid kg/m3  dimensionless stream function  vorticity references 1. morgan, v. t., “the overall convective heat transfer from smooth circular cylinders", adv. heat transfer, vol. 11, pp. 199–264, (1975). 2. dennis, s. c. r., hudson, j. d and smith, n. " steady laminar forced convection from a circular cylinder at low reynolds numbers", j. phys. fluids, vol. 11, pp. 933–940, (1968). 3. karniadakis, g. e," numerical simulation of forced convection heat transfer from a cylinder in cross.flow", int. j. heat mass transfer, vol. 31, pp. 107–118, (1988). 4. yang, y. t., chen, c. k. and s. r. wu, "transient laminar forced convection from a circular cylinder using a body-fitted coordinate system", j. thermophys., vol. 6, pp. 184–188, (1992). 5. saha, a. k. "unsteady free convection in a vertical channel with a builtin heated square cylinder", j. numerical heat transfer, 38, part a, p.p 795-818,( 2000). 6. farouk, b. güceri, s.i. " natural and mixed convection heat transfer around a horizontal cylinder within confining walls",j. num. heat transf. part a, 5,pp. 329–341, (1982) . 7. biswas, g. , laschefski, h. , mitra, n.k. ,and fiebig, m."numerical investigation of mixed convection heat transfer in a channel with a built-in square cylinder", j. num. heat transf. part a, 18 , pp. 173–188 (1990). 8. turki, s. abbassi, h. and nasrallah, s.b., " twodimensional laminar fluid flow and heat transfer in a channel with a built-in heated square cylinder", int. j. therm. sci., 42,pp. 1105–1113, (2003). 9. atul sharma and v. eswaran "heat and fluid flow across a squre cylinder in the two dimensional laminar flow regime".j.numerical heat transfer , part a , pp. 247269, (2004). 10. nogotov, e.f. "applications of numerical heat transfer", hemisphere publishing corp. washington. (1978). sajida lafta ghashim jassim ijcpe vol.11 no.1 (march 2010) 35 fig.(3) average nusselt number versus position along the cylinder surface (different gr values at re=50) fig.(5) average nusselt number versus position along the cylinder surface (different gr values at re=100) fig.(4) average nusselt number versus position along the cylinder surface (different gr values at re=-50) fig.( 6) average nusselt number versus position along the cylinder surface (different gr values at re=-100) numerical study of the mixed convection flow over a square cylinder 36 ijcpe vol.11 no.1 (march 2010) fig. (7( isotherm contour maps at re=50 for different values of gr number sajida lafta ghashim jassim ijcpe vol.11 no.1 (march 2010) 37 fig.( 8) isotherm contour maps at re=-50 for different values of gr number numerical study of the mixed convection flow over a square cylinder 38 ijcpe vol.11 no.1 (march 2010) fig. (9) isotherm contour maps at re=100 for different values of gr number sajida lafta ghashim jassim ijcpe vol.11 no.1 (march 2010) 39 fig.(10) isotherm contour maps at re=-100 for different values of gr number numerical study of the mixed convection flow over a square cylinder 40 ijcpe vol.11 no.1 (march 2010) fig.) 11) streamline contour maps at re=50 for different values of gr number sajida lafta ghashim jassim ijcpe vol.11 no.1 (march 2010) 41 fig. (12) streamline contour maps at re=-50 for different values of gr number numerical study of the mixed convection flow over a square cylinder 42 ijcpe vol.11 no.1 (march 2010) fig. (13) streamline contour maps at re=100 for different values of gr number sajida lafta ghashim jassim ijcpe vol.11 no.1 (march 2010) 43 fig.(14) streamline contour maps at re=-100 for different values of gr number numerical study of the mixed convection flow over a square cylinder 44 ijcpe vol.11 no.1 (march 2010) (a) re=50 (b) re=-50 (c) re=100 (d) re=-100 fig. (15)variation of mean nu number with gr number at different values of re number 0 1 2 3 4 5 6 0 20000 40000 60000 80000 100000 120000 gr n u 0 1 2 3 4 5 6 7 0 20000 40000 60000 80000 100000 120000 gr n u 2 2.5 3 3.5 4 4.5 5 0 20000 40000 60000 80000 100000 120000 gr n u 2 2.5 3 3.5 4 4.5 5 5.5 6 0 20000 40000 60000 80000 100000 120000 gr n u sajida lafta ghashim jassim ijcpe vol.11 no.1 (march 2010) 45 fig.(16) average nusselt number versus position along the cylinder surface (different gr values ) refernece [5] fig.(17) comparsion of average nusselt number versus position along the cylinder surface (at gr=1x10 4 ) with reference [5]. 0 5 10 15 20 25 0 5 10 15 20 25 position along surface cylinder n u x gr=9x10000 gr=4x10000 gr=2.25x10000 gr=1x10000 gr=6.4x1000 gr=1.6x1000 0 2 4 6 8 10 12 14 0 5 10 15 20 position along surface cylinder n u x present study refernce [4] iraqi journal of chemical and petroleum engineering vol.14 no.2 (june 2013) 4148 issn: 1997-4884 zinc element traces to inhibit scale formation on cooling tower and air cooler systems shaymaa abdul rahman ahmed reshan chemical engineering department – college of engineering – university of baghdad –iraq abstract calcium carbonate is predominantly present in aqueous systems, which is commonly used in industrial processes. it has inverse solubility characteristics resulting in the deposition of scale on heat transfer surface. this paper focuses on developing methods for inhibition of calcium carbonate scale formation in cooling tower and air cooler system where scaling can cause serious problems, zncl 2 and zni 2 has been investigated as scale inhibitor on aisi 316 and 304. zncl 2 were more effective than zni 2 in both systems, and aisi 316 show more receptivity to the chlorides salt compared to aisi 304. the inhibitors were more effective in cooling tower than air cooler system. aisi 316 show more constant inhibition efficiency in cooling tower with maximum of 95% with zncl 2 and 83% with zni 2 . key words: scale .cooling tower, air cooler, zinc compounds, aisi 316 and 304. introduction it is known that aqueous systems such as cooling tower, boilers, heat exchangers, heating/cooling system, paper mills, fire service water, reactors, and the like are subjected to the formation of deposition on the internal surfaces which are in contact with the circulating water .in the operation of systems unitizing cooling tower and like so, quantities of water, as required, are introduced and utilized at a rate depending upon the service requirements of the installation. makeup water universally contains a quantity of impurities and the contaminants which, unless treated, contribute to a constant build up of deposits on the working surfaces of the system [1, 14]. normal operation of these systems results in the consumption of reasonably large quantities of water, and as water is lost from the system, normally through evaporation, levels of concentration of these contaminants and impurities increase. these contaminants and impurities are normally the same elements or compounds which commonly contribute to water hardness, specifically certain calcium salts along with certain quantities of iron oxides. the precipitation of these compounds known to be scaling, which is serious problem in units because the scale layer acts as a thermal insulator,because the thermal conductivity of scale material is such greater than that of copper and steel [2], as given in table (1). iraqi journal of chemical and petroleum engineering university of baghdad college of engineering zinc element traces to inhibit scale formation on cooling tower and air cooler systems 42 ijcpe vol.14 no.2 (june 2013) -available online at: www.iasj.net table 1, thermal conductivity of some used metals compound k (w/m.k) calicium carbonate 0.8 silica 0.08 copper 343 steel 75 scale precipitation (precipitation fouling) occurs when ever process condition lead to creation of supersaturation with respect to one or more of the sparingly soluble salts, which is the most important factor determining the intensity of scaling [3]. supersaturation condition is achieved when a solution is concentrated beyond the solubility limits of one or more of its constituents by evaporation. supersaturation condition can also be achieved by change in temperature. most of the frequently encountered scaling salts caco 3 , mg (oh) 2 , caso 4 , and ca 3 (po 4 ) 2 exhibits inverse solubility characteristics, i.e., solubility decrease with increasing temperature. the dependence of salt solubility on temperature or presence of evaporation will often be the deriving force for scaling. the important distinction is between salts with normal or retrograde dependence of solubility on temperature. the salts with natural solubility increase their solubility with increasing temperature and thus will foul the cooling surfaces. the salts with inverse solubility will foul the heating surface. [4] supersaturation solution is at unstable equilibrium and relieves its supersaturation by precipitating of solid phase. attainment of super-saturation alone is not sufficient for a system to be precipitated. at relatively moderate super-saturation, the solution can remain stable without precipitation for a certain time, which is termed the delay or induction period. only at sufficient high super-saturation level, the induction period is virtually absent and precipitation will be instantaneous. the induction period phenomenon is of utmost particular importance in scale control efforts. the widely used technique discussed below, of scale control by dosage of anti-scaling, is based on the increase of induction period induced by the presence of the anti-scaling. [5, 13] once the initial scale layer is formed, subsequent deposition is facilitating. growth of crystal layer on a flow surface involves several consecutive processes: diffusional transport of the crystal – forming ions towards the crystallizing layer; incorporation of the ions on growth sites of the crystal lattice; adhesion and removal processes. scale build up on heat transfer surfaces causes ongoing expense to the owner and an increase in thermal impedance and thus decreases the rate of heat transfer through the surface. this contributes to an overall loss of efficiency of the system. it would be very desirable to be able to quickly remove scale deposits from metal surface under safe conditions without the use of strong acid. it would also be desirable to be able to remove scale deposits from metal surfaces without the risk of perforating the metal wall of the system. further, it would be desirable to be able to remove scale from metal surfaces while leaving a stable protective coating. [6] the removal of scale and iron oxide deposits is necessary to prevent corrosion beneath the scale area since corrosion control agents are unable to effectively contact the metal surface. if the deposits are not removed, under deposits corrosion can penetrate through the metal, breaching the containment. once this occurs, fluid starts leaking from system and system must be taken off line and this portion shaymaa abdul rahman ahmed reshan -available online at: www.iasj.net ijcpe vol.14 no.2 (june 2013) 43 of the system must be repaired or replaced. thus, clean scale –free heat transfer surface represent a desirable condition in cooling water system. [7] the main scale control strategies are: removal or reduction of scale forming species; inhibition of deposition by dosage of anti-scalant; controlled scale deposition with periodic cleaning schedules. a number of approaches have been attempted to create an effective scale cleaner. cleaning can be done either mechanically or with the use of chemicals. mechanical cleaning obviously takes a great deal of down time and dose not always gets all scale out. the most widely used chemical technique for scale control is by dosage of anti-scaling. this technique is cost effective because in many cases scaling can be suppressed with only few ppm of anti-scaling, typically less than 10 ppm. the system is simple in that, it may be controlled by adding the product directly from the container to cooling water and the system is capable of maintaining a reasonable amount of control over scale.[8] the inhibition mechanisms is done by the adsorption of the inhibitor on the crystallization surface acts to delay nucleation , reduce the precipitation rate, and distorts the crystal structure such that the deposit tenacity to the flow surface is weakened. commonly used anti-scaling are derived from three chemical families: condensed poly phosphate, organo phosphates, and poly phosphates. numerous studies have shown that all inhibitor polymers are effective only within a relatively narrow range of molecular weights, typically around (1000-5000 da). it is presumed that the size of the inhibiting molecule should be sufficiently large so that when adsorbed on the scaling ,it occupies a sufficient area for exerting its effect, but it should not be so large that it lacks sufficient mobility and that its adsorption rate is too slow. a low molecular weight fraction of a given inhibitor is adsorbed on the scaling species more rapidly than a high molecular weight fraction, but the adsorbed quantity is larger with the high molecular weight fraction. [9] some researchers found that the combination of 15 ppm of maleic acid and 6 ppm of phosphorus acid and 20 ppm of hydrogen peroxide gave consistently high level of inhibition [11]. it has been suggested by other researches to use weak base (ammonium) and strong acid (hydrochloric, sulfuric) salts instead of using acids alone. the salts hydrolyze and safely acidify the environment. [1] nh 4  + h 2 o = nh 4 oh +h  however these anti-scaling are expensive and sometimes will result in environmental problems. there is ample evidence in the literature that small amount of metal impurities, such as fe, mg, cu, and zn which are commonly encountered in water ,can affect the nucleation and crystallization rate of precipitation caco 3 . coetzee et al. reporte that cu 2 was found to be only half as effective as zn 2 , while mg 2 required concentration levels 1000 times larger to produce comparable effects [11]. pernot et al. indicated that fe 2 was quarter as effect as zn 2 for caco 3 scale inhibition [12]. also yang founds that 2 to 5 mg/l of zinc ions is very effective in membrane permeability in reverse osmosis. but the full potential of zn 2 for scale suppression has been very scantily explored so far [15]. this paper presents an investigation the addition of zncl 2 and zni 2 at zinc element traces to inhibit scale formation on cooling tower and air cooler systems 44 ijcpe vol.14 no.2 (june 2013) -available online at: www.iasj.net different concentration (1,2,3,and 4 ppm) to scale precipitation on aisi 304 and 316 stainless steel ( because of their wide use and important application ) in cooling tower and air cooler system for two weeks of working for each and the results were compared to the optimum condition of that of ammonium sulfate (50 ppm) [1], and to the optimum composition of (15+6+20) ppm of maleic acid and phosphorous acid and hydrogen peroxide respectively at the same conditions[9]. experimental work models of air cooler system and cooling tower system have been built up in laboratory and it make as possible to perform a simulation of processes that runs industrially. figures (1) and (2) presents diagrams of the models. the air cooler system consists of hot air supply (which consists of fan blow air through the heating coil to the air cooler windows). the hot air suppliers used to pour out hot air at 45˚c through sheets of wetted metal samples (aisi 304 and 316) that are fixed in air cooler windows. water pump has been used to circulate the water at about 30˚c from air cooler box up to the windows through down the metal samples. the flow of the circulating water has been controlled by rotameter and fixed at 160 l/hr. the cooling water system consist of tower contained within a basin which contains 40l of water, the tower contained a series of slats positioned in a way to provide uniform cascade flow of water and water distributor position at the top of the tower, the system has a water pump used to circulate the water from the basin to the tower, the flow of water was controlled at 160 l/hr using rotameter. the temperature of the water to the tower was at 45˚c and it was controlled using thermostat and thermocouple and leaves the tower at 38˚c. air was draw out of tower at 35˚c using air draft fan positioned at the top of the tower which is with drawn air from the bottom of the tower through holes in the bottom at about 25˚c. the metal samples were positioned on the slates of the tower. r water rotameter m make up water f hot air fan b air cooler box p water pump fig. 1, schematic diagram for air cooler system m make up water p pump r rotameter h heater a.d air draft fan fig. 2, laboratory cooling tower system f r m b p p r h recycle water m a.d shaymaa abdul rahman ahmed reshan -available online at: www.iasj.net ijcpe vol.14 no.2 (june 2013) 45 the samples used in both systems were stainless steel 304 and 316; the compositions for both of them are shown in table (2). the metal samples were of 20x10x2 mm size. the samples were progressively wet polished to grit silicon carbide paper, after polishing, the samples were washed with distilled water and degreased with acetone and weighed. the samples then positioned in each system for two weeks for each run. after the test, they were mildly rinsed with distilled water and acetone and weighted. the first run of the two systems was un-inhibited runs. the other runs in each system receive a one per week dosage of zinc chloride and zinc iodide in several concentrations (1ppm, 2ppm, 3ppm, and 4ppm) for each compound. also two other experiments where made ,one using ammonium sulfate (50ppm) [12], and the other by using 1.5 gm/l of mixture of inhibition solution consist of (15ppm maleic acid, 6ppm phosphorous acid, and 20ppm hydrogen peroxide) [9]. table 2, composition of aisi 304 and 316 stainless steel aisi cr ni c mn si p s n mo 304 18.6 9.4 0.08 1.9 0.73 0.045 0.028 0.09 316 17.2 11.5 0.08 2 0.75 0.045 0.3 0.1 2.4 result and discussion in this study the efficiency of the inhibitors used have been calculated, according to the equation inhibition eff. % =1∆w in / ∆w unin where ∆w in is the weight change of metal samples in the inhibited solution. ∆w unin is the weight change of metal samples in uninhibited solution. in cooling tower system , figures 3 and 4, zinc chloride was more effective than zinc iodide on the aisi 316 than 304 ,with stability in all concentration (316 is more stable to the environment effect than 304 because of its structure) and we get the better inhibition efficiency (95%) at 2-3 ppm of zinc chloride with aisi 316. aisi 304 shows decrease in inhibition efficiency after increasing the concentration beyond 2 ppm (this may be imputing to the increase of acidity and less stability of 304 comparing to that of 316). zinc iodide shows the same behavior as zinc chloride with both ss 403 and 316, but with less inhibition efficiency. we get maximum inhibition at 2 ppm (83%) for both metal samples, but with 316, increasing the concentration beyond 2 ppm gave us the same efficiency to that of 1 ppm (79%). in the air cooler system zinc chloride gives the same efficiency as increasing the concentration increased beyond 2 ppm and it was the same for both aisi 304 and 316 (about 70%). inhibition activity of zinc iodide slightly decrease after increasing the concentration beyond 2 ppm , the maximum was at 2ppm and it was 67% for 316 (figure 6) and 60% for 304 (figure 5) . in air cooler system the efficiency was less than that in cooling tower at the same concentration for both compounds ,this my be attributed to the hot air effect on drying the metal samples. in both metal samples and in both systems zinc chloride was more effective than zinc iodide, this attributed that the aqueous solution of zinc element traces to inhibit scale formation on cooling tower and air cooler systems 46 ijcpe vol.14 no.2 (june 2013) -available online at: www.iasj.net zinc chloride are acidic, and the acids works as scale removal. the acidity aqueous zinc chloride solution relative to solution of other zinc ions salts is due to the formation of tetrahedral chloro aqua complexes, where the reduction of in coordination number from 6 to 4 further reduces the strength of o-h bonds in the solvent water molecules. [16] metal ions present in water can acts as the deriving force. zinc compound influence the reaction in two ways, the first being in the solution were they can form complexes with the reaction ions altering both activity coefficient and the rate out which transformation reaction occur. secondly, zinc ions can be adsorbed on to the surface of the reaction solids, adsorption of these foreign ions is preferred at high energy sites that are also favored for dissolution and crystal growth. the inhibition of calcite growth can cause the formation of aragonite, it is believed that this is how existing carbonate scale in a system is removed. when using ammonium sulfate at concentration of 50 ppm, the inhibition efficiency was 93% for both metal samples in cooling tower system while zinc compounds shows 95%. in air cooler system the efficiency was 70%. the composition of (15ppm maleic acid and 6ppm phosphorous acid and 20ppm hydrogen peroxide) shows very high efficiency, it was about 98% for aisi 316 and 95% for aisi 304 in cooling tower system, and 82% for aisi 316 and 80% for aisi 304 in air cooler system. both of the last inhibitors have environmental problem and corrosive action on the metals. fig. 3, effect of concentration of zncl 2 and zni 2 on 304 ss in cooling tower system for two weeks operation 40 50 60 70 80 90 100 0 1 2 3 4 5 conc. ppm % i n h ib it io n e ff . zncl2 zni2 shaymaa abdul rahman ahmed reshan -available online at: www.iasj.net ijcpe vol.14 no.2 (june 2013) 47 fig. 4, effect of different concentration of zncl 2 and zni 2 on 316 ss in cooling tower system for two weeks operation fig. 5, effect of concentration of zncl 2 and zni 2 on 304 ss in air cooler system for two weeks operation fig. 6, effect of concentration of zncl 2 and zni 2 on 316 ss in air cooler system for two weeks operation 40 50 60 70 80 90 100 0 1 2 3 4 5 conc. ppm % i n h ib it io n e ff . zncl2 zni2 40 50 60 70 80 90 100 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 conc. ppm % i n h ib it io n e ff . zncl2 zni2 40 50 60 70 80 90 100 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 conc. ppm % i n h ib it io n e ff . zncl2 zni2 zinc element traces to inhibit scale formation on cooling tower and air cooler systems 48 ijcpe vol.14 no.2 (june 2013) -available online at: www.iasj.net conclusion 1zinc chloride was more effective than zinc iodide in all situations; this was attributed to the acidity of zinc chloride aqueous solution. 2zinc compounds were more effective on aisi 316 than 304. 3zinc compounds were more efficient in cooling tower system than in air cooler system, this can be imputing to the hot air effect in air cooler system. 4preferring of usage zinc salts instead of ammonium sulfate and (15ppm maleic acid and 6ppm phosphorous acid and 20ppm hydrogen peroxide) because of the latest environmental problem and corrosion action. references 1szymura, teresa, physicochemical problem of mineral processing, 40, 99-108, (2006). 2cho, y.i., liu, r., w.i., mcfarland, and fusegni," study of scale removal method in double-pipe heat exchangers ", heat transfer engineering, 21, 50-57, (2000). 3hasson, d., dark, a., semiat, r., desalination 2003, 157,193-207. 4hong, lu. "composite fouling of heat exchanger surface ", nova science books. n.y. (2007) 5mulline, j.w., crystallization, 3 rd .ed; butterworth heinemann; oxford, (1997). 6backer, j.s., jadd, s.j.," magnetic amelioration of scale formation ", water resources, 30,247-260, (1996). 7frayne, colin, "cooling water treatment", chemical publishing co.,inc.,newyork,ny, (1999). 8donalddson, j.d., grimes, s. "lifting the scale from our pipes", new scientist, 117, 20-24, (1988). 9hsson, d., in understanding heat exchanger fouling and its mitigation; bott, t.r. ed.; begell house: new york, (1999). 10shyu, l.l., united state patents, 5292449, mar.8, (1994). 11coetzee, p.p., yacoby, m., howell, s., mubenga, s., "scale reduction and scale modification effecting induced by zn and other metal species in physical water treatment", water sa, 24(1), 77-84, (1998). 12pernot, b., euvarard, m., remy, f., simon, p., "influence of zn (ii) on the crystallization of calcium carbonate application to scaling mechanisms", j.water serv. res. tech. aqua. , 48(1), 16-23, (1999). 13ascolese, c.r., bain, d.j., "take advantage of effective cooling water-treatment programs", chemical engineering progress, 3, 49-54, (1998). 14loraine, a., huchler, p.e.,"nonchemical treatment systems: histories, principles and literature review". international water conference, 22 oct. (2002). 15yang, q., "inhibition formation of caco 3 scaling in reverse osmosis system by zinc ions", chinese j. chem. eng., 14(2)178-183, (2006). 16brown, d.i.," the chemical bonds in inorganic chemistry, the bond valance mode", oxford science publications, 2001. iraqi journal of chemical and petroleum engineering vol.14 no.3 (september 2013) 2331 issn: 1997-4884 removal of phenol compounds from aqueous solution using coated sand filter media asrar al-obaidy chemical engineering department-college of engineering-university of baghdad-iraq abstract coated sand (cs) filter media was investigated to remove phenol and 4-nitrophenol from aqueous solutions in batch experiments. local sand was subjected to surface modification as impregnated with iron. the influence of process variables represented by solution ph value, contact time, initial concentration and adsorbent dosage on removal efficiency of phenol and 4-nitrophenol onto cs was studied. batch studies were performed to evaluate the adsorption process, and it was found that the langmuir isotherm effectively fits the experimental data for the adsorbates better than the freundlich model with the cs highest adsorption capacity of 0.45 mg/g for 4nitrophenol and 0.25 mg/g for phenol. the cs was found to adsorb 85% of 4nitrophenol and 65% for phenol at an initial concentration of 25 mg/ℓ. key words: coated sand, phenol, 4-nitrophenol, adsorption, batch study. introduction wastewaters containing phenolic compounds are serious environmental problem , and cannot simply be released into the environment without treatment . several methods are currently used for the removal of phenol and its derivatives from wastewater , e.g. microbial degradation [1] ,chemical oxidation [2] , incineration [3] , solvent extraction [4] and irradiation [5] . however, by far the most frequently used technology is adsorption by solid phase . several different adsorbent solids such as activated carbon [6, 7, 8, 9 ], silica [10] , glass powder [11] , polymeric resins [12,13] , fly ash [ 14, 15, 16, 17, 18, 19, 20 ], peat [21, 19], kaolinite [22] and zeolites [23, 24] have all been proposed to remove phenolic pollutants from wastewaters . recent studies have shown that metal oxides (such as iron oxides, aluminum oxides or manganese oxides) have relatively high surface area and surface charge, and can be applied to the removal of heavy metals and organic matters from water and wastewater [25, 26, 27, 28]. however , most of metal oxides are available only as fine powders or are generated in separation. beside, due to their low conductivity, the aqueous solutions as hydroxide floc or gel. therefore, they are limited to reactor configurations incorporating with large sedimentation basins or filtration units because of the difficulty in solid/liquid metal oxides alone are not suitable as filter media [29]. iraqi journal of chemical and petroleum engineering university of baghdad college of engineering removal of phenol compounds from aqueous solution using coated sand filter media 24 ijcpe vol.14 no.3 (september 2013) -available online at: www.iasj.net recently, some researchers have developed techniques for coating metal oxides onto sand surface in order to overcome the above problems of using metal oxides powders in water treatment process . in this study kind of iron-oxide-coated sand was prepared by coating process and the phenol and 4-nitro phenol adsorption from aqueous solution was investigated by batch experiments in order to get available cs filter media for effective removal of phenol and its derivatives. experimental procedure adsorbent material to prepare cs filter media, natural quartz sand (qs), with a particle size ranging from 0.5 to 0.8 mm, was used as the supporting material for iron oxide. firstly , the sand was prewashed several times with tap water until run-off was clear . after the sand was dried at 110ºc, it was soaked in 0.1m hci solution for 24h. then the sand was rinsed to remove impurities, dried at 110ºc and finally stored in capped bottles. stock solution of 2.5 m fe (iii) was prepared by dissolving feclɜ·6h₂o in deionized water. cs was prepared with the following coating processes: the solution containing a mixture of 400 ml of 2.5 m fe (iii) and 1 ml of 10 m naoh was pourd over 800 ml dried sand placed in a heatresistant dish . after gentle agitation , the mixture was heated for 96 h at 110ºc and then at 200ºc until it appeared to be dry. after cooling , the coated sand was washed with tap water until run-off was clear , then the coated sand was dried at 110ºc . after above coating step was finished , the sand was coated again according to the same step , and stored in polystyrene bottles for further use [30] . adsorbate material the stock solution was prepared by diluting the required quantities of phenol or 4-nitrophenol with distilled water to obtain adsorbate solution of various initial concentrations. the effect of ph, contact time and (cs) loading was studied using 25 mg/ℓ of phenol or 4-nitrophenol and 5 gm of cs was adjusted with either dilute hcl or naoh solution to a constant value. all the ph measurements were done with a ph meter (827 ph lab, metrohm). each flask was capped and inverted 3 times to mix the contents thoroughly and then allowed to stabilize for 10 to 15 min . the effect of cs loading at 307 k were conducted by contacting initial phenol and 4-nitrophenol concentrations of 20 mg/l with varying quantities of cs ( 1 to 7 ) g in a series of 25 ml pyrex conical flasks at a ph of 3.12 ± 0.10 . the effect of initial concentration of phenol and 4-nitrophenol was studied using different initial concentrations of (20, 40, 60, 80, 100 mg/l) with 1 g of cs, stirred at 180 rpm for 3 hours. the concentration changes of the individual compounds in the solutions were determined by means of uv-vis spectrophotometry (sq4802 double beam). the maximum absorbance for each solute from the highest standard solution prepared were found using scanning spectrophotometry at the respective wavelength maxima λ . the λse used were 270 nm and 320 nm for phenol and 4-nitrophenol respectively. the calibration plot of absorbance vs. concentration for all the standards showed a linear working range up to 30 mg/l with correlation coefficient ≥ 0.99. the supernatant solutions obtained after adsorption asrar al-obaidy -available online at: www.iasj.net ijcpe vol.14 no.3 (september 2013) 25 were also analysed using the same wavelengths . adsorption kinetics kinetic tests using a mixture of phenol or 4-nitrophenol were performed in a batch fashion . the initial solutes mix was analyzed to determine the initial concentration of the solutes before mixing with the cs. for each adsorption data point , a 25 ml aliquot of the adsorb ate solution having an initial phenol or 4-nitrophenol concentration of 20 mg/l , constant cs loading of 5 g at temperature of 307 k were introduced into a series of 25 ml pyrex conical flasks for different contact times and at a ph of about 3. the conical flasks were placed and shaken in a labcon platform shaking incubator ( model fsimspo16 ) where the last sample was collected after 300 min of contact time and at a constant stirring speed of 200 rpm . the samples were covered throughout the experiment and the supernatant solution filtered through whatman micro-fiber filters of 0.45 µm to determine the concentration of each solute left after different time intervals of agitation (15,30,60,….,300 min) .the flasks were shaken in a labcon platform shaking incubator ( model fsimspo16 ) to attain equilibrium after about 22 h of contact time and at a constant stirring speed of 200 rpm. adsorption isotherms the ability of the prepared cs to remove the phenol or 4nitro phenol from aqueous solutions was determined under batch mode conditions. the equilibrium isotherms were determined by mixing 5 gram of cs with different concentrations (20, 40, 60, 80 and 100 mg/l) of each solution of phenol or 4nitro phenol in conical flasks. flasks were shaken at 200rpm overnight to assure that equilibrium was reached. the residual concentration was analyzed using atomic absorption spectrophotometer. data obtained from the adsorption isotherm tests were used to determine the adsorption capacity of cs . the equilibrium adsorption uptake and percentage removal of phenol from the aqueous solution qe (mg/g) was determined using the following relationship : amount adsorbed ( ) …(1) (mg of adsorb ate / g of adsorbent) and, % removal = ( ) …(2) where: co is the initial sorbet concentration (mg/ℓ) ce is the equilibrium sorbet concentration (mg/ℓ) v is the volume of solution (ℓ) w is the mass of the adsorbent (g) results and discussions characterization of cs filter media qs and cs surface photographs are shown in fig.1. magnification by sem of 2000 and 25000x is made to show the morphology of the surfaces. it can be seen that the deposition had changed the smooth surface of sand. new cracks occurred on the surface with new microspores appeared between the new crystals or cubes deposited of iron oxide. it can be concluded that the coating step changed the morphology of natural sand. the amount of iron ox hydroxide deposits onto sand was determined to be about 30 mg-fe/g-sand jianbo et al [30] had used the same coating procedure and analyzed this amount to be 31.13mg-fe/g-sand. removal of phenol compounds from aqueous solution using coated sand filter media 26 ijcpe vol.14 no.3 (september 2013) -available online at: www.iasj.net (a) qs (b) cs (c) qs (d) cs fig.1, sem for natural sand qs (a and c) and the prepared cs (b and d). (a) and( b) at 2000 magnification. (c) and (d) at 25000 magnification adsorption time fig. (2) represents the results for the effect of contact time on the removal of phenol and 4-nitrophenol from aqueous solution at an initial concentration of 20 mg/ℓ. it can be seen that the amount of all the adsorbents adsorbed onto cs increases with time and about 65%, 70% of phenol and 4-nitrophenol had been removed within the first 15 min of agitation, respectively, after which the process approaches equilibrium. the time profile for adsorbents is a single, smooth, and continuous curve leading to saturation, which suggests possible monolayer coverage of the adsorbents on the surface of the cs. fig. 2, effect of contact time on percentage removal adsorption isotherms the analysis of the adsorption isotherms is important for design asrar al-obaidy -available online at: www.iasj.net ijcpe vol.14 no.3 (september 2013) 27 purpose. therefore, experimental data were analyzed with well-known two parameter adsorption isotherm models including the langmuir, freundlich isotherms. fig. 3, adsorption isotherms of phenol and 4nitrophenol on cs phenol and 4-nitrophenol adsorption isotherms obtained for cs are shown in fig.3. ttese isotherms represent the adsorption behavior of phenolic compounds at various temperatures as a function of equilibrium aqueous concentration, for a contact time of 24 h. the rearranged langmuir isotherm can be described as: = + ( ) ( ) …(3) where: β is an adsorption equilibrium constant related to the binding energy the langmuir adsorption isotherm is based on the concept that solid surfaces have finite adsorption sites. when all the adsorption sites are filled, the surface will no longer be able to adsorb solute from the solution. the maximum amount of solute (qm) adsorbed in a particular system can be estimated from the isotherm parameters. the plot of ⁄ vs. ⁄ should yield a straight line. the slope is ⁄ and the intercept is ⁄ . the freundlich adsorption isotherm can be written in the form: log q = log kf + ⁄ log cₑ …(4) the freundlich isotherm predicts that the adsorb ate concentration on the surface of an adsorbent will increase when there is an increase in the initial adsorb ate concentration in the aqueous solution. the experimental data obtained are plotted as log qₑ versus log cₑ, to obtain the constants k and ⁄ . the constant kf is a comparative measure of the adsorption capacity of the adsorbent, while is an empirical constant. the magnitude of gives an indication of the favorability of adsorbent/adsobate system. values of signify that the solute has a low affinity for the adsorbent at low concentration. likewise, a value of is an indication of favorable adsorption and a high affinity between the solute and solid phase. the freundlich (kf and ⁄ ) and langmuir constant (β and q ) determined from the adsorption isotherm for phenol and 4-nitrophenol depicted in figs. 3 and 4 are summarized in table 1. the correlation coefficient values determined for each of the adsorption isotherm indicates that the langmuir model effectively fits the experimental data better than the freundlich model. the adsorption capacity for phenol and 4-nitrophenol at the maximum residual concentration was calculated using the langmuir constant β at an initial concentration of 20 mg/l for all the adsorbents and the values obtained were 3.779 mg/g, 3.679 mg/g for phenol and 4-nitrophenol, respectively. removal of phenol compounds from aqueous solution using coated sand filter media 28 ijcpe vol.14 no.3 (september 2013) -available online at: www.iasj.net table 1, adsorption isotherm models for phenol and 4-nitrophenol on cs model parame ter ph pnph langmuir qm 3.779 3.679 β 0.784 1.115 r 2 0.837 0.962 freundlich ⁄ kf 4.265 0.728 n 37.07 37.53 r 2 0.764 0.998 fig. 3, the linearized freundlich adsorption isotherm for phenol and 4-nitrophenol mixtures onto cs fig. 4, the linearized langmuir adsorption isotherm for phenol and 4-nitrophenol mixtures onto cs effect of initial ph the ph of the aqueous is an important variable that influences the adsorption at the solid-liquid interface. the effect of variation of the initial solution ph (3,4,5,6,7,8,9,10,11,12,13) on the adsorption of phenol and 4 nitro phenol is illustrated in fig.5. for cs, the adsorption removal percentage decreases with an increase in ph from 3.6 to 10.2 and from 3.5 to 8 for phenol and 4-nitrophenol respectively. fig.5 also shows that 70% maximum removal percentage of phenol is achieved at ph value of 3.6.while for 4-nitrophenol, a maximum removal percentage of 97% is obtainedat ph of 3.5.therefore, the values of 3 6 and 3.5 are considered to be the best ph for removal of phenol and 4-nitrophenol, respectively. fig. 5, effect of solution ph on percentage removal effect of initial concentration the effect of initial concentration of phenol and 4-nitrophenol was studied using different initial concentrations of (20, 40, 60, 80, and 100) with 1 g of each cs, stirred at 180 rpm for 3 hours. this effect is shown in fig.6. increasing initial concentration of phenol and 4-nitrophenol decreases the removal efficiency as can be seen in fig. 6, especially for phenol. this can asrar al-obaidy -available online at: www.iasj.net ijcpe vol.14 no.3 (september 2013) 29 be due to the absence of adsorption sites for the extra molecules at a constant amount of the adsorbent, while for the adsorption of 4nitrophenol, which have smaller radius, it slightly different is high for all concentrations. fig. 6, effect of initial concentration on the removal efficiency effect of adsorbent loading the effect of adsorbent loading is studied using 25 ml of solution of initial concentration of 20 mg/ℓ using (1, 2, 5 and 7g) of cs, stirred at constant speed of 200 rpm for 3 hours. the removal efficiency increased as the amount of cs increased as it appears in fig.7. the increase in the efficiency can be explained by the increasing surface area or binding sites where the adsorption takes place with the increasing of cs dosage. fig. 7, effect of adsorbent loading on the removal efficiency conclusions 1. a maximum 4-nitrophenol removal percentage of 97% were obtained at 3.5 solution ph and 300 min contact time, and a maximum 4nitro phenol removal percentage of 87% at 20 mg/ℓ initial concentration solution stirred at 180 rpm for 3 hours. 2. the adsorption process obeys firstorder kinetics. the langmuir isotherm fits and describes the adsorption mechanism better than the freundlich one for the two phenol derivatives. 3. the prepared coated sand cs was found to have good adsorption properties and can provide an effective technology based on adsorption/ filtration using cs filter media for phenol derivatives removal from water and wastewater. references 1munaf e., zein r., kurnidi r. and kurnidi i. (1997), the use of rice husk for removal of phenol from waste water as studied using 4aminoantipyrine spectrophotometric method. environ. technol. 18(3) 355-358. 2bertoncini c., raffaelli j., fassino l., odetti hs and botani ej. (2003), phenol adsorption on porous and non-porous carbons. carbon 41 (6) 1101-1111. 3 khalid m., joly g., renaud a. and magnoux p., (2004). removal of phenol from water by adsorption using zeolites. ind. eng. chem. res. 43, 5275-5280. 4 aksu z. (2005). application of biosorption for the removal of organic pollutants: areview. process biochem. 40, 997-1026. 5denilzi a., cihanger n., tuzmen n. and alsancak g. (2005). removal of chlorophenols from aquatic removal of phenol compounds from aqueous solution using coated sand filter media 30 ijcpe vol.14 no.3 (september 2013) -available online at: www.iasj.net systems using the dried and dead fungus pleurotus sajor caju. bioresour. technol. 96, 59-62. 6garcia-araya jf, beltran fj, alvarez p. and masa fj. (2003). activated carbon adsorption of some phenolic compounds present in agro industrial wastewater. adsorption 9 (1), 107-115. 7nouri s., haghsersht f., and maxlu gq. (2002). comparison of adsorption capacity of p-cresol and pnitrophenol by activated carbon in single and double solute. adsorption 8, (3), 215-223. 8abbas h. sulaymon and kawther w. ahmed (2008). competitive adsorption of furfural and phenolic compounds onto activated carbon in fixed bed column. environmental science and technology, 42(2), 392-397. 9abbas. h. sulaymon, dheyaa w. abbood and ahmed h. ali (2012). removal of phenol and lead from synthetic wastewater by adsorption onto granular activated carbon in fixed bed adsorbers: prediction of breakthrough curves. desalination and water treatment, 40, issue 1-3, 244-253. 10hanna k., beurroies i., denoyerl r., desplantiergiscard d., galarneu a., and direnzo f. (2002). sorption of hydrophobic molecules by organic/inorganic mesostructures j. colloid interface sci. , 252, 276283. 11atun g. (1992). the adsorption of nitrophenols on a special adsorbent prepared from glass powder. spectrosc.lett. 1992, 25, (5), 741-756. 12 wagner k. and schultz s. (2001). adsorption of phenol, chlorophenols, and dihydroxybenzens onto unfunctionalized polymeric resins at temperatures from 294.15 k to 318.15 k. j. chem. eng. data 46,322-330. 13 abburi k.(2003). adsorption phenol and p-chlorophenol from their single and biosolute aqueous solutions on amberlite xad-16 resin. j. hazard. mater. 105, 143156. 14 akgerman a. and zardkoohi m. (1996). adsorption of phenolic compounds on fly ash. j. chem. eng. data. 41, 185-187. 15kao pn., tzeng jh. and huang tl. (2000). removal of chlorophenols from aqueous solution by fly ash. j. hazard. mater. 76, 237-249. 16sarkar m., acharya kp. and bhattacharya b. (2005). removal characteristics of some priority organic pollutants from water in a fixed bed fly ash column. j. chem. technol. biotechnol. 80, 13491355. 17sarkar m. and acharya kp. (2006). use of fly ash for the removal of phenol and its analogues from contaminated water. waste manage. 26, 559-570. 18 srivastava vc., swamy mm., mall id., prasad b. and mishra im.(2006). adsorptive removal of phenol by bagasse fly ash and activated carbon: equilibrium, kinetics and thermodynamics. colloids surf. a. 272, 89-104. 19viraraghavan t. and alfaro f. (1998). a by peat, fly ash and bentonite. j. mater. 57, 59-70. 20 jh potgieter et. al. (2009). adsorptive removal of various phenols from water by south african coal fly ash. water sa (on line), vol.35, no. 1, 89-96. 21allen sj. (1987). equilibrium adsorption isotherms for peat. fuel 66, 1169-1175. appl. sci. 1 (4) 321326. 22barhoumi m., beurroies i., denoyel r., said h. and hanna k. asrar al-obaidy -available online at: www.iasj.net ijcpe vol.14 no.3 (september 2013) 31 (2003). co-adsorption of alkylphenols and nonionic surfactants onto kaolinite. colloids surf. a. 219, 25-33. 23koh s. and dixon jb. (2001). preparation and application of organominerals as adsorbents of phenol,benzene and toluene. appl. clay sci. 18, 111-122. 24 sismanoglu t. and pura s. (2001). adsorption of aqueous nitrophenols on clinoptilolite. colloids surf. a. 180, 1-2. 25mark m. benjamin, ronald s. sletten, et al. (1996). sorption and filtration of metals using iron-oxidecoated sand. water research, 30, 11, 26092620. 26 g. villasenor nano, t.j. strathmann (2006). ferrous iron sorption by hydrous metal oxides. journal of colloid and interface science, 297,443-454. 27a.h. sulaymon, w.m.s. kassim and mohsin j. nasir (2012). competitive adsorption of organic pollutants from wastewater onto organoclay in batch adsorber. international journal of environment and development. 28nada s. ahmedzeki (2013). adsorption filteration technology using iron-coated sand for removal of lead and cadmium dsorption of phenol from wastewater ions from aquatic solutions. desalination and water treatment, 11 feb. 29theis, t.l. and iyer, r., et al. (1992). evaluating a new granular iron oxide for removing lead from drinking water. j. am. water works assoc., 84, 101-105. 30 jianbo l., liping s., xinhua z., bin l., yinlei l., lei z., (2009). removal of phosphate from aqueous solution using iron-oxidcoated sand filter media: batch studies, 2009. international conference on environmental science and information application technology. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.20 no.2 (june 2019) 71 – 75 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: majid m. majeed , email: majid.majeed@hotmail.com , name: ayad a. alhaleem, email: ayadah62@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. enhancing drilling parameters in majnoon oilfield majid m. majeed and ayad a. alhaleem university of baghdad abstract the objective of drilling parameters optimization in majnoon oilfield is to arrive for a methodology that considers the past drilling data for five directional wells at 35 degree of inclination as a baseline for new wells to be drilled. also, to predicts drilling performance by selecting the applied drilling parameters generated the highest rate of penetration (rop) at each section. the focal point of the optimization process is to reduce drilling time and associated cost per each well. the results of this study show that the maximum rop could not be achieved without sufficient flow rate to cool and clean the bit in clay intervals (36" and 24") hole sections. although the influence of combination of weight on bit (wob), round per minute (rpm), and hydraulic horsepower on the bit in (16", 12 1/4" and 8 1/2") hole sections is a key to reduce drilling time, therefore, the drilling parameters produced the fastest rop per each section was considered as optimum parameters likely to apply for the future wells. keywords: drilling parameters, drilling time, weight on bit , rate of penetration received on 02/09/2018, accepted on 18/12/2018, published on 30/06/1029 https://doi.org/10.31699/ijcpe.2019.2.9 1introduction proper planning of any drilling project is the key to optimizing operations and minimizing expenditures. therefore the first step in planning a well should be the gathering of all available data from the past wells, in this respect, it is essential to be completely familiarized with all sources of information, the availability of data, and the information normally associated per each section ‎[1]. drilling optimization is normally characterized by the rate of penetration (rop), where several parameters contribute towards the rop such as weight on the bit (wob), round per minute (rpm), flow rate, hydraulics and bit type ‎[2]. one of the attempts for drilling optimization purpose was presented by david hankins (2014) where the author gathered data from preexisting wells that were drilled within the same field, necessary data includes bit records, operational drilling parameters and lithological information encountered during drilling. the preexisting data is crucial since it is used to predict the results of different drilling scenarios when planning new wells, as it will be used as a reference for the upcoming wells. therefore there is no major difference between the plan and the actual drilling time ‎[3]. majnoon oilfield is a super-giant oil field located 60 km from basrah city in southern iraq. majnoon is one of the richest oil fields in the world with an estimated 38 billion barrels of oil in place in multiple reservoirs; the field was named majnoon, which means 'crazy' in arabic in reference to the dense accumulation of oil in the area. several directional wells have been drilled in majnoon oil field to produce from different reservoirs such as mishrif, nahr-umer, and zubair pay zones, in order to increase the production of the field ‎[4]. many research studies have been performed for the optimization of drilling operation having an objective to optimize footage drilled and minimize drilling cost. therefore a massive amount of data were collected and analyzed from offset wells drilled in the majnoon oilfield including bit types, mud type, wob, rpm, and flow rate as well as lithological column encountered during drilling for five directional wells at 35 degree inclination. in order to predict the drilling behavior for new wells, the drilling time per each hole section must be considered to find the best operating drilling parameters. based on each hole section comparisons of the drilled wells, the optimum drilling parameters was considered. 2well design the wells in the majnoon oil field were drilled either to mishrif carbonates, nahr-umer sands, or zubair sands. first, the top hole section is drilled across upper fars formation with 36" bit to an approximately 100m depth where the weak formations existed, and 30" conductor casing is cemented in place to ensure that the water table had been adequately cased-off. second, the surface hole section is drilled to seal off the unconsolidated formations which typically consists of clay and sands with 24" bit to 600 m depth. the 18 5/8" surface casing is set vertically and cemented to surface and the kick-off point designed in the next hole section at sufficient distance below the previous casing shoe depth ‎[5]. https://doi.org/10.31699/ijcpe.2019.2.9 m. m. majeed and a. a. alhaleem / iraqi journal of chemical and petroleum engineering 20,2 (2019) 71 75 27 third, the intermediate section is drilled with 16" bit to 1500 m across lower fars and ghar formations. the 13 3/8" casing is run and cemented 150m inside the previous casing. the objective is to allow the next hole section to be drilled through potential loss circulation zones without the risk of initiating a well control problem due to severe drilling fluid losses ‎ [6]. next, is the second intermediate 12 1/4" section is drilled to 2500m through dammam, um er radhumma, alaiji, shiranish, hartha, saadi, tanuma, and khassib formation. the 9 5/8" casing run and cemented 100m inside the previous casing section, the objective is to seal off loss circulation and hydrocarbon zones. finally, the 8 1/2" production section is drilled to reach well total depth (td) and desired reservoir zone; the 7" casing liner run and cemented 150 m inside the previous casing ‎[7]. 3data processing and discussion according to the gathered necessary data from preexisting wells that were drilled in majnoon oilfield, that includes daily drilling reports (ddr), mud logging data, bit records, final well report (fwr), and lithological information encountered while drilling it is essential to forecast the drilling time per each hole section when planning new well. therefore there are no major discrepancies between the planned and actual drilling time. take into considerations that the drilling time to complete every hole section was normalized to same depth reference. the fastest rop per each hole section was considered to find the best operating drilling parameters. in order to achieve effective drilling optimization, an extensive analysis was conducted on which parameters generate higher rop fig. 1 and fig. 2. fig. 1. 36" hole section comparisons ‎[8]. fig. 2. 24" hole section comparisons ‎[8] in well e, the 36" and 24" hole sections described in fig. 1 and fig. 2 respectively, identified as the fastest section drilled among the offset wells, as a result of 90 rpm, 20-30 kilo pounds (klbs) wob, flow rate 500-900 gallon per minute (gpm), also the use of 65,000 parts per million (ppm) of mud salinity helped to retard the rate of clay hydration ‎[8]. the chosen drilling mud type per each section must be designed to mitigate hole instability and drilling problems, it is also important to maintain low gravity solids and high gravity solids at a minimum level to enhance drilling performance ‎[9]. the associated drilling parameters are shown in fig. 3 is the best drilling parameters to use in these sections for future wells ‎[8]. fig. 3. optimum drilling parameters for 36" and 24" hole sections ‎[9] m. m. majeed and a. a. alhaleem / iraqi journal of chemical and petroleum engineering 20,2 (2019) 71 75 27 fig. 4 clearly shows that 16" hole section in well d is the fastest directional section drilled, this is due to successful selection of polly crystalline diamond compact bit (pdc) type (sfd75dh) and utilized drilling parameters of wob 15-30 klbs, rpm 120, flow rate 900 gpm generated average rop 20m/hr ‎[8]. fig. 4. 16" hole section comparisons ‎[8] fig. 5 shows the effect of increasing the rpm and flow rate on the rop; it clearly shows that rop increases directly with rpm and flow rate at sufficient hsi, although at 800m depth observed rop increases directly with wob when rpm and flow rate is constant. fig. 5. optimum drilling parameters for 16" hole section [10] as seen in fig. 6 that 12 1/4" hole section in well e is the fastest section drilled among the previous wells drilled, this is due to the fact of the significant value of hydraulic horsepower per square inch applied during drilling with 25 klbs wob, 150 rpm, and flow rate 700800 gpm. it is well deserved to use the associated drilling parameters of this section as a guideline for the future wells in order to drill wells in time efficient manner ‎ [11] as displayed in fig. 7. fig. 6. 12 1/4" hole section comparisons ‎[8] fig. 7 shows the significant effect of the hsi on the rop, the higher hsi results from the suitable nozzle selections and higher flow rate led to impressive rop along the entire hole section. fig. 7. optimum drilling parameters for 12 1/4" hole section ‎[10] fig. 8 indicates that good drilling performance was achieved during drilling 8 1/2" hole section in well c. however at 3600m rop declined from 24m/hr to 10m/hr due to severe vibrations, but rop recovered after adding lubricants to the drilling mud where the desired drilling parameters implemented to drill the section in a short period of time compared to the previous wells drilled ‎[11] as shown in fig. 9. fig. 8. 1/2" hole section comparisons ‎[8] m. m. majeed and a. a. alhaleem / iraqi journal of chemical and petroleum engineering 20,2 (2019) 71 75 27 in fig. 9 it's important to notice that started drilling with higher wob, flow rate and rpm resulted in remarkable rop of 24m/hr until entered the anhydrite layers at 3300m depth, where the rop declined dramatically due to severe vibrations, treatment to the drilling fluids was considered by adding lubricants and mitigated the vibrations successfully. fig. 9. optimum drilling parameters for 8 1/2" hole section ‎ [10] 4conclusions 1in the 36" and 24" hole sections for well e the major problem to overcome is the clay hydration, where the bit balling affect the rop. therefore the use of 65,000 ppm mud salinity with 90 rpm, 20-30 klbs wob, and 500-900 gpm flow rate achieved constant rop without bit balling signs during drilling. 2the successful selection of 16" pdc bit type (sfd75dh) in well d within associated wob of 30 klbs, 120 rpm, and flow rate 900 gpm showed incredible rop of 20 m/hr. consequently this section was drilled in 1.75 days, which represent significant reduction in drilling time. 3in 12 1/4" hole section of well e, hydraulic horse power of 2.5 per square inch which required for optimum hole cleaning varies directly with 25 klbs wob, 140 rpm, consequently, hydraulic horse power of 2.5 was sufficient to drill at 18 m/hr rop.. 4in well c while drilling 8 1/2" hole section encountered stringers of anhydrite, rop declined from 24m/hr to 10 m/hr in short period. hence the added of lubricants to the drilling mud enhanced the rop and avoided the bad vibrations. nomenclatures gpm gallon per minute pdc polly crystalline diamond compact ppm parts per million rop rate of penetration rpm round per minute td total depth wob weight on bit references [1] richard caredn, "planning a well" chapter one, tulsa oklahoma: ogci petro skills training, 2006. [2] h. abdul hadi, “correlation of penetration rate with drilling parameters for an iraqi field using mud logging data”, ijcpe, vol. 16, no. 3, pp. 35-44, sep. 2015. [3] david hankins, saeed salehi," an integrated approach of optimizing drilling parameters using advanced drilling optimizer” lafayette: journal of petroleum engineering, 2014. [4] m. m. majeed and a. a. alhaleem, “selection of suitable drilling parameters for obtaining high rate of penetration in majnoon oilfield”, ijcpe, vol. 20, no. 1, pp. 65-68, mar. 2019. [5] iraq ministry of oil "iraq's second petroleum licensing round majnoon contract area", press release, 2009. [6] miguel armenta, rob tinkhof, "improving drilling performance at majnoon oilfield", uae: spe/iadc drilling conference and exhibition, 2013. [7] marcle vesconte ," the majnoon field – a case study of drilling operations in remote area of iraq" texas: spe/ iadc drilling conference and exhibition, 2014. [8] south oil company" final well reports", iraq: 2014. [9] nazaneen said , ayad a. alhaleem “ analysis of stuck pipe incidents in khabaz field” university of baghdad, ijcpe, 2018. [10] south oil company" mud logging data", iraq: 2014. [11] south oil company" bit records", iraq: 2014. http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/260 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/260 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/260 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/260 https://www.hindawi.com/journals/jpe/2015/281276/abs/ https://www.hindawi.com/journals/jpe/2015/281276/abs/ https://www.hindawi.com/journals/jpe/2015/281276/abs/ https://www.hindawi.com/journals/jpe/2015/281276/abs/ https://doi.org/10.31699/ijcpe.2019.1.9 https://doi.org/10.31699/ijcpe.2019.1.9 https://doi.org/10.31699/ijcpe.2019.1.9 https://doi.org/10.31699/ijcpe.2019.1.9 https://www.onepetro.org/conference-paper/spe-166685-ms https://www.onepetro.org/conference-paper/spe-166685-ms https://www.onepetro.org/conference-paper/spe-166685-ms https://www.onepetro.org/conference-paper/spe-167949-ms https://www.onepetro.org/conference-paper/spe-167949-ms https://www.onepetro.org/conference-paper/spe-167949-ms https://www.onepetro.org/conference-paper/spe-167949-ms https://doi.org/10.31699/ijcpe.2018.4.6 https://doi.org/10.31699/ijcpe.2018.4.6 https://doi.org/10.31699/ijcpe.2018.4.6 m. m. majeed and a. a. alhaleem / iraqi journal of chemical and petroleum engineering 20,2 (2019) 71 75 27 تحسين ادائيه معامالت الحفر في حقل مجنون النفطي ةالخالص الوصول الى وسيمو تعتبر الغرض من تحميل معامال ت الحفر المستخدمو في حقل مجنون النفطي ىو اساس لالبار التي سوف يتم حفرىا 57البيانات المتوفره لالبار المحفوره سابقا" لخمسو ابار مائمو بدرجو مستقبال", كذلك يتم استخداميا لتخمين ادائيو الحفر باالعتماد عمى معامالت الحفر المختاره بناءا" عمى اقصى .معدل اختراق لكل مقطع ساسي من اختيار المعامالت المااليو ااناء عمميو الحفر ىو لتقميل الوقت المرا د بو الوصول الى اليدف اال نيايو كل مقطع وبالتالي تقميل الكمفو االقتصاديو لكل بئر يتم حفره, االستنتاج الرئيسي من ىذا البحث ىو معرفو تحقيقو من غير تسميط معدل جريان المتطمبات االساسيو لمحصول عمى اعمى معدل اختراق والذي اليمكن "( كذلك اليمكن تحقيق اعمى معدل اختراق من غير 46" و 58مناسب لتنظيف وتبريد الحافره في المقطعين ) "(, 5.7"و 64.47"و68الموازنو بين الوزن المسمط عمى الحافره وسرعو دوران عمود الحفر في كل من المقاطع ) انخفض الوقت الالزم الكمال البئر وبالتالي كمفو اقل باالعتماد عمى لذلك كمما زاد معدل اختراق الحافره معامالت الحفر التي حققت اعمى معدل حفرفي حقل مجنون النفطي. iraqi journal of chemical and petroleum engineering vol.12 no.4 (december 2011) 14 issn: 1997-4884 energy generation from static water head developed by forward osmosis adel a. al-hemiri, ghazwan a. mohammed and ghazi f. naser department of chemical engineering, baghdad university, baghdad, iraq in this work, the possibility of utilizing osmosis phenomenon to produce energy as a type of the renewable energy using thin film composite ultra low pressure membrane tfc-ulp was studied. where by forward osmosis water passes through the membrane toward the concentrated brine solution, this will lead to raise the head of the high brine solution. this developed static head may be used to produce energy. the aim of the present work is to study the static head developed and the flux on the high brine water solution side when using forward and reverse osmosis membranes for an initial concentration range from 35-300 g/l for each type of membrane used at room temperature and pressure conditions, and finally calculating the maximum possible power generated from developed static head. introduction osmosis a physical phenomenon extensively studied by scientists in various disciplines of science and engineering. early researchers studied the mechanism of osmosis through natural materials, and from the 1960s, special attention was given to osmosis through synthetic materials. osmotically driven membrane processes utilize an osmotic pressure difference, which is generated when a semi-permeable membrane separates a dilute feed solution from a more concentrated draw solution, to drive the permeation of water from the feed solution to the draw solution. these processes have the potential to sustainable produce clean drinking water or electric power [1]. forward osmosis (fo), a subset of osmotically driven membrane processes is appealing because it requires no applied hydraulic pressure and has a low membrane fouling propensity [2]. because of these benefits, fo is attracting attention as a new technology to augment water supplies using non-traditional sources. the potential of this technology was demonstrated in a variety of applications, such as desalination [3, 4], wastewater reclamation [5, 6], industrial wastewater treatment [7], brine concentration [8], osmotic membrane bioreactors [9], liquid food processing [10, 11], and protein concentration [12]. renewable energy can be extracted wherever two streams of different salinity or different chemical potential meet. considering that the salinity of seawater yields osmotic pressures of approximately 2.7mpa and that the osmotic pressure of river water is relatively insignificant, a large portion of the 2.7mpa can be used for power generation. the pressure-retarded iraqi journal of chemical and petroleum engineering university of baghdad college of engineering energy generation from static water head developed by forward osmosis 2 ijcpe vol.12 no.4 (december 2011) available online at: www.iasj.net osmosis (pro) is one method that can be used to realize this energy. pro is preferred for osmotic hydropower generation and is a similar phenomenon to fo but with applying a pressure on the brine solution side lower than its osmotic pressure, so that pro will act in conditions between those of fo and ro. pro for power generation has been continuously studied by loeb and co-workers [13]. additionally intensive studies funded by the european union with the main objective being to develop membranes for pro power that have a production capacity equivalent to at least 4 w/m² [14]. experimental section studied variables in the present work the variables taken into consideration are classified into categories according to system arrangements made. the arrangements are: type of membrane, fo and ro membranes and the effect of initial concentration of the brine solution in the brine solution side. 35,100,165.230 and 300 g / l. experimental apparatus. the apparatus consists of the following parts: (1) two glass vessels type qvf 15 cm in diameter with 3.5 l capacity. one vessel contains the brine solution and the other contains water. (2) two membranes type ro and fo. one of the membranes is placed between the two glass vessels; the active layer will face the vessel holding the brine solution. the glass vessels and the membrane are assembled with two flanges and a silicone seal. (3) a glass pipe type qvf with a length of 2m and diameter of 1.8 cm is connected on the brine solution vessel to measure the hydraulic head. (4) a glass l shaped fitting type qvf connected to a rubber hose which will collect the liquid from the brine solution side into a graduated glass cylinder to measure the permeate flux. figure 1 shows a simple sketch of the apparatus used. fig .1, apparatus used in present study hydraulic head measurements. the measurements consist of the following steps: (1) initially a brine solution was prepared by putting 35g nacl in a 1 liter flask and completing the volume to 1 liter with fresh water. the conductivity of the solution is measured using conductivity meter, and then the solution was placed in one of the qvf vessels and with the active side of the membrane facing this solution. (2) 3.5 l of fresh water was placed in second qvf vessel with the non active side facing the fresh water. the conductivity of the fresh water was measured. (3) the value of the hydraulic head was recorded with time in one hour intervals. this operation is repeated many times using the fo and ro membranes for initial brine concentrations range of 35 to 300 g/l. permeate flux measurements. the same procedure as above was repeated but for measuring the permeate flux. this was done by collecting the overflowing volume of permeate in a measuring cylinder and recording the time for a given volume. results and discussion hydraulic head developed. the hydraulic head developed when using the fo type membrane is greater than that obtained when using ro type membrane as shown in table 1 below which lists the head developed ( h ) per unit area of membrane after 24 h for initial brine concentration ( c ) from 35 to 300 g / l using ro and fo membranes. adel a. al-hemiri, ghazwan a. mohammed and ghazi f. naser available online at: www.iasj.net ijcpe vol.12 no.4 (december 2011) 3 table 1, head developed (h) at different initial brine concentration (c) using ro and fo membranes after 24 h at room conditions [15]. the relation between the initial brine concentration ( c ) and the head developed ( h ) can be represented by the following proposed equation: h=kc n (1) where k and n are constants that depend on the type of membrane used. table 2 below, lists the values of the constants in equation 1 for ro and fo membranes. table 2, constants of equation (1) for ro and fo membranes [15]. membrane ro fo k 0.3931 1.6437 n 0.7687 0.5542 r 2 0.9915 0.9511 permeate flux. the permeate flux ( jw ) when using fo membrane is nearly double that when ro membrane was used as shown in table 3. table 3, permeate flux ( jw ) at different initial brine concentration (c) using ro and fo membranes after 24 h at room conditions [15]. c jw ( ro ) jw ( fo ) 35 1.12 2.44 100 5.82 7.18 165 6.79 12.00 230 7.39 13.96 300 8.30 15.61 g / l l / m 2 . day l / m 2 . day power generated. the maximum power ( pm ) obtained from the head developed using ro and fo membranes is equal to the static pressure of the head developed and is given by the following equation: pm=ρ.g.h (2) where ρ is the density of brine solution and g is the gravity of acceleration. table 4 lists the maximum possible power in watts per unit membrane area ( w/m 2 )obtained using ro and fo membranes for initial brine concentration range from 35 to 300 g / l. table 4, power generated (pm) at different initial brine concentration (c) using ro and fo membranes [15]. c pm ( ro ) pm ( fo ) 35 0.71 1.46 100 1.51 2.00 165 2.05 3.14 230 3.02 3.90 300 3.76 4.72 g / l w / m 2 w / m 2 conclusions the use of osmotic processes as a source of renewable energy is very promising, however, with the obtained results alongside the available literature it remains beyond achieving yet. literature cited 1mi b. and elimelech m., (2010),“organic fouling of forward osmosis membrane: fouling reversibility and cleaning without chemical reagents”, journal of membrane sicence, vol.348,pp.337345. 2kravath r.e. and davis j.a., (1975), “desalination of seawater by direct osmosis”, desalination, vol.16, pp.151155. 3cath, t.y., childress, a.e. and elimelech, m. (2006), “forward osmosis: principles, applications, and recent developments”, journal of membrane science,vol. 281,pp.70-87. 4cartinella j.l., cath t.y., flynn m.t., miller g.c., hunter k.w. and childress a.e., (2006), “removal of natural steroid hormones from wastewater using membrane contactor process”,environmental scince &technology, vol.40,pp.7381-7386. c h ( ro ) h ( fo ) 35 6.24 12.90 100 13.30 17.65 165 18.06 27.69 230 26.61 34.35 300 33.12 41.54 g / l m / m 2 . day m / m 2 . day energy generation from static water head developed by forward osmosis 4 ijcpe vol.12 no.4 (december 2011) available online at: www.iasj.net 5cath t.y., gormly s.,beaudry e.g., flynn m.t., adams v.d. and childress a.e.,(2005), “membrane contactor process for wastewater reclamation in space.part i. direct osmotic concentration as a pretreatment for reverse osmosis”, journal of membrane science,vol.257,pp.85-98. 6holloway r.w., childress a.e., dennett k.e. and cath t.y.,(2007), “forward osmosis for concentration of anaerobic digester centrate”, water research, vol.41,pp.4005-4014. 7tang w. and ng h.y.,(2008), “concentration of brine by forward osmosis:performance and influence of membrane structure”, desalination, vol.224,pp.143-153. 8achilli a., cath t.y., marchand e.a. and childress a.e.,(2009), “the forward osmosis membrane bioreactor: alow fouling alternative to mbr processes”, desalination, vol.239,pp.10-21. 9garcia-castello e.m., mccutcheon j.r. and elimelech m., (2009), “performance evaluation of sucrose concentration using forward osmosis”, journal of membrane science, vol.338,pp.61-66. 10jiao b., cassano a. and drioli e.,(2004), “recent advanced on membrane processes for the concentration of fruit juices: areview”,journal of food engineering, vol.63,pp.303-324. 11yang q., wang k.y. and chung t.s., (2009), “anovel dual-layer forward osmosis membrane for protein enrichment and concentration”, separation and purification technology, vol.69, pp.269-274. 12baker r., (2004), “membrane technology and applications”, 2nd ed., wiley. 13loeb s., (2002) “large-scale power production by pressure-retarded osmosis using river water and sea water passing through spiral modules”, desalination, vol.143, pp.115–122, cited in reference 24. 14aaberg r.j., (2003) “osmotic power—a new and powerful renewable energy source”, refocus,vol. 4, pp.48– 50, cited in reference 24. 15ghazi f. naser,(2011), “ measurement of static water head developed by forward and reverse osmosis”, m. sc. thesis, chemical engineering department, of the college of engineering, university of baghdad. iraqi journal of chemical and petroleum engineering vol.17 no.4 (december 2016) 125136 issn: 1997-4884 removal of heavy metals from industrial wastewater by using ro membrane ahmed h. algureiri and yossor r. abdulmajeed chemical engineering department – college of engineering – university of nahrain e-mail: gureiri71@gmail.com and yossor_riadh@yahoo.com abstract industrial wastewater containing nickel, lead, and copper can be produced by many industries. the reverse osmosis (ro) membrane technologies are very efficient for the treatment of industrial wastewater containing nickel, lead, and copper ions to reduce water consumption and preserving the environment. synthetic industrial wastewater samples containing ni(ii), pb(ii), and cu(ii) ions at various concentrations (50 to 200 ppm), pressures (1 to 4 bar), temperatures (10 to 40 o c), ph (2 to 5.5), and flow rates (10 to 40 l/hr), were prepared and subjected to treatment by ro system in the laboratory. the results showed that high removal efficiency of the heavy metals could be achieved by ro process (98.5%, 97.5% and 96% for ni(ii), pb(ii) and cu(ii) ions respectively). the permeate flux for all h.m ions was ranged between (10 to 56 l/m 2 .hr). the low level of the heavy metals concentration in the permeate implies that water with good quality could be reclaimed for further reuse. the ro membrane is characterized by very high efficiency as the h.m. ions removal of up to (97%) with good productivity and medium pressure that means a medium cost of the ro system. introduction decreased water resources and increased uses have required a worldwide campaign for innovative water management practices. the use of effective technologies, such as membranes, for wastewater treatment containing heavy metals ions will allow the implementation of water recycling systems in industrial facilities [1], as well as reduce harming the environment. as a result, wastewater discharge cost and freshwater supply payments will decrease, and reduce environmental risks. the world health organization (who) has identified heavy metals allowed for drinking water, as well as the appropriate levels for agriculture and soil and marine and other district level [2]. table 1 shows the minerals that can be contained in industrial water, and the highest allowable limit for drinking water, according to the world health organization. for removal of heavy metals from wastewater, wide types of water treatment techniques are available such as adsorption, electrodialysis, complexation-ultrafiltration process, university of baghdad college of engineering iraqi journal of chemical and petroleum engineering mailto:gureiri71@gmail.com mailto:yossor_riadh@yahoo.com removal of heavy metals from industrial wastewater by using ro membrane 126 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net reverse osmosis, and nanofiltration system. the selection of a particular treatment depends on a number of factors, for example, waste type, contaminant concentration, level of cleanup required and economics. use of most techniques (except reverse osmosis and nanofiltration), can be practical and cost-effective only with concentrated wastewater (contain high concentration of heavy metal ions), but they will be ineffective when applied to low concentration wastewater that contain heavy ions less than 100 ppm, while there are techniques to be effective in the removal of low concentrations of metals ions only, and be inefficient with high concentrations. as for reverse osmosis system, it is effective in all concentrations even the very low values. many natural and synthetic adsorbents can effectively remove dissolved heavy metals; most of them show some disadvantages such as poor adsorption capacity, a low efficiency, cost ratio, and ineffectiveness at high metal concentration [3]. in this research the reverse osmosis processes because of its many advantages such as high efficient, low cost, simple operation, and work with any feed concentration. three metal ions were selected for a search (nickel, lead, and copper) ions, as they represent different industries and scattered, with different parameters; concentration, pressure, temperature, ph, and flow rate, the values of parameters were chosen as the most appropriate for operating conditions that achieve less cost and best production. table 1: limiting, uses, and toxicity of heavy metals h.m *level of h.m./ppm uses toxicity pb 0.01 building construction lead acid – battery bullets [4]. negatively influence plant growth [5]. cu 0.1 used as a conductor of heat and electricity, building material, tharanitharan venkatesan, 2014 various alloys [6]. this toxicity is possibly due to redox cycling and the generation of reactive oxygen species that damage dna [7]. fe 0.3 found in most industries that use equipment and iron pipes plating shops, wire drawing operations steel mills, and chemical milling [4]. osteoporosis, liver cirrhosis cardiomyopathy arrhythmia heart failure heart attack, hypothyroidism, hypopituitarism, adrenal gland neurodegeneration [7]. ni 0.02 used to manufacture stainless steel, nonferrous alloys, batteries, electronics, and aerospace applications [8]. with immoderate amounts, can become toxic. cause liver damage, decreased body weight, heart, and skin agitation [9]. zn 3 used for galvanizing iron, more than 50% of metallic zinc goes into galvanizing steel, also in the preparation of certain alloys, building construction, roofing and gutters, the negative plates in some electric batteries [10]. zinc increase in the blood leads to a sense of bitterness or bitterness mouth food generally, vomiting, nausea and stomach pain, and these symptoms are similar to symptoms of poisoning [10]. hg 0.002 used in equipment (e.g. switches, gauges, thermometers, manometer) and in chemicals (e.g. phenyl mercuric acetate, caustic soda [11]. effects on the nervous, digestive and immune systems, and on lungs, kidneys, skin and eyes [12]. as 0.01 used in paints, dyes, soaps, metals, and semiconductors, mining, agriculture, also as wood preservative [1]. cause skin damage or problems with circulatory system, and an increased risk of getting cancer [6]. http://www.iasj.net/ ahmed h. algureiri and yossor r. abdulmajeed -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 127 removal processes of heavy metals there are many processes for removing heavy metals ions from wastewater like chemical precipitation, coagulation-flocculation, flotation, adsorption, ion-exchange, electrodialysis and membranes system [13]. these processes aim to reduce the amount and proportion of metals to the allowable limit and what is not a danger to health or the environment [14]. reverse osmoses process reverse osmosis membrane needs pressure. the aim of ro membrane to separate the h.m. ions, salts and other contents from water using a selective membrane. the membrane is designed to allow water to pass through while retaining solutes. when the feed water is pressurized, pure water passes through the membrane into the permeate stream. the pressure of feed water depends of contents of water whenever a large concentration of water inside, need greater pressure. the concentrate water that does not permeate the membrane leaves the system as reject. ro system block diagram is shown in figure 1. in order to understand the mechanism of reverse osmosis process natural osmosis mechanism must be understood. osmosis is a special kind of diffusion; the diffusion of water molecules across a permeable membrane from low solute concentration to high solute concentration like the plant absorbs the water from the soil by its root. figure 2 shows that using a semipermeable membrane to divide the container into two parts, full one part with a high salt concentration, will see the water begin transfer across the membrane from lower salt concentration towards the water container with the higher salt concentration, then the rate of water flow will gradually reduce to a final stop when concentration on both sides became almost equal and the system be in equilibrium [16]. whereas osmosis occurs naturally without pressure applied required, when reverse the process of osmosis need to apply pressure to the system. that’s mean reverse osmosis process, is osmosis process in reverse. figure 3 shows the process of reverse osmosis. fig. 1: ro membrane process [15] fig. 2: natural osmosis process [15] fig. 3: principle of reverse osmosis process [15] feed water concentrate permeate http://www.iasj.net/ removal of heavy metals from industrial wastewater by using ro membrane 128 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net advantages heavy metals removal by using of reverse osmosis includes [15]:  operating costs are medium.  energy costs are medium.  hard water softening.  remove salts and other ions in a large percent.  remove the heavy metals in a large percent.  no chemicals addition.  the value of ph does not change much.  no phase change.  simple equipment.  effective in all concentrations even the very few. experimental work in this work, three types of h.m. solutions [ni(ii), cu(ii) and pb(ii)] had been selected. table 2 shows the h.m. ions and its specifications. the specification of ro membrane cells had been used shows in table 3. table 2: specifications of h.m. ions h.m. ion m.wt (g/mol) density g/cm 3 solubility in water (molal) ni(ii) niso4.6h2o 262.58 1.948 77.5 at 30 o c pb(ii) pb(no3)2 331.21 4.53 52 at 20 o c cu(ii) cu.so4.5h2o 249.7 2.286 1.502 at 30 o c table 3: specification of ro membrane cells type of membrane ro membrane material module spiral wound size (id, length), mm 100x1000 activated area, m 2 7.9 maximum operating temperature, o c 45 maximum applied pressure, bar 5.5 manufacturer filmtec company feed water ph range 2-10 maximum feed water turbidity 1.0 maximum feed flow sdi (15 min) 5 experimental procedure three types of heavy metals were used, with five different parameters. for every test the feed must be prepared first by dissolving the required quantity of heavy metal in pure water with required parameters and the feed tank was filled with in. water from the feed tank was pumped it with different pressures, where change the pressure through the gradual closing of the valve of reject water (it should not be closed completely). the reading of feed water pressure gauge (before entering to membrane cell) to get the pressure required for each operation. figure 4 shows the schematic diagram of the ro process. to obtain the required feed flow rate it must controlled by the valve after the pump and before entering the membrane. the pure water was used in the process for the purpose of measuring the flux coefficient and for cleaning before and after every test. after water preparation according to the required specifications and regulating the pressure, flow rate and other parameters as stated, the system was to operate for at least 3 minutes to reach steady state. in the meantime the permeate and rejected water return to the feed tank for the purpose of maintaining the water concentration. after that time permeate water was collected in flask to test the amount of heavy metals to calculate the membrane rejection and determine the permeate flow rate to calculate the membrane flux. http://www.iasj.net/ ahmed h. algureiri and yossor r. abdulmajeed -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 129 fig. 4: schematic diagram of the ro process results and discussion 1. steady state time figure 5, shows the change of removal ratio of ni(ii) ion, with time, until steady state is reached. initially the removal starts from 30%, 45%, 48%, and 50%. then the removal begin to increase significantly till it was fixed at 98.5%, 98.2%, 97.5%, and 97.2% after 30 minutes for ni(ii) ion concentrations 50 ppm, 100 ppm, 150 ppm, and 200 ppm respectively. dow company reported that the steady state time for reverse osmoses membrane is 45 to 60 minutes [17]. figure 6 shows effect of time on permeate flux of ni(ii) ion. the permeate flux increase from 8 and 10 l/m 2 .hr. it has taken 30 minutes to reach to study state at 42.5, and 40.5 l/m 2 .hr for pure water and ni(ii) ion concentrate 200 ppm respectively. that means every change in cross flow velocity; the process needs a few minutes to reach steady state. this period was necessary to obtain the stabilization of the polarization layer after changing the cross flow velocity. as a result, the removal and permeate flux reached a steady value after a few minutes [18]. fig. 5: effect of time on ni(ii) ion removal for ro (conc.=100ppm, pressure=3 bar, temperature=30 o c, ph=5.5, feed flow rate=30 l/hr) fig. 6: effect of time on permeate flux of ni(ii) ion for ro (conc.=0 ppm and 200ppm, p=4 bar, t=30 o c, ph=5.5, and flow=30 l/hr) http://www.iasj.net/ removal of heavy metals from industrial wastewater by using ro membrane 130 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net 2. effect of operating parameters on removal percentage 2.1. effect of the feed concentration the feed concentrations (50, 100, 150, 200 ppm) are chosen for all metals because almost these concentration are present in most of the industrial wastewater and that the removal process is influenced by variables more high concentrations. figure 7 shows the increase in concentration for all h.m. leads to decrease of removal percentage, with fixing all other parameters (pressure 3 bar, ph 5.5, feed flow rate 30 l/h, and temperature 30 ºc). at 50 ppm concentration of heavy metals, the percentage of removal was 98.5%, 97.5% and 96.1% for nickel (ii), lead (ii) and copper (ii) respectively. and at 200 ppm concentration of heavy metals, the removal decreased to 97.2%, 96.1% and 94.2 for nickel (ii), lead (ii) and copper (ii) respectively. figure 8 shows the effect of the concentration on flux of ro, where increase in the concentration for all h.m. led to little decreasing in flux. initial value of permeate flux was 42.5 l/m 2 .hr, decrease to 40.5, 40.3, 40.6 l/m 2 .hr at concentration 200 ppm for ni(ii), pb(ii) and cu(ii), respectively. these decreasing in removal and permeate flux for ro system because the increasing in feed concentration leads to turbulence in flow at boundary layer. this leads to obstruction in the pass of the ions across the pores, causing to decrease the removal and flux [19]. there is another explanation that the increasing in feed concentration leads to increase in the concentration of the negatively charged ions at the membrane surface, resulting in increasing shield of negatively charged membrane. this results lead to reduce the repulsion forces on the positively charged ions and thus decreasing removal and flux. kai yu wang, 2007, reported the removals and permeates flux of polybenzimidazole (pbi) nanofiltration hollow fiber membrane to cuso4 decrease with an increasing in metal ion concentration [20]. fig. 7: effect of concentration on h.m. ions removal for ro (pressure=3 bar, temperature=30 o c, ph=5.5, feed flow rate =30 l/hr) fig. 8: effect of conc. on permeate flux for ro (pressure=3 bar, temperature=30 o c, ph=5.5, feed flow rate=30 l/hr) 2.2. effect of pressure pressure is very important parameter to operate the ro membrane, the membrane system have certain pressure difference depending on the type of material that must be removed. figure 9 shows the effect of pressure on the removal of nickel (ii), lead (ii), and copper (ii) ions for ro system, the initial concentration was fixed as 100 mg/l, and initial ph was adjusted at 5.5, feed flow rate was 30 l/h, and temperature was 30 ºc. from this figure it can be seen that the removal of metals increase from 92%, http://www.iasj.net/ ahmed h. algureiri and yossor r. abdulmajeed -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 131 93% and 91.4 % of ni(ii), pb(ii) and cu(ii) respectively at 1 bar, to 98.4%, 97.1% and 95.4 % of ni(ii), pb(ii) and cu(ii), respectively at 4 bar. this behavior was because that membrane incompletely prevents dissolving h.m. ions in feed water, therefore some h.m. passage through the membrane are present. when feed pressure is increased, these h.m. ions passage is increasingly overcome as water is pumped through the membrane at a high rate than h.m. can be transported. the increasing in the curve which represents the removal percentages will stop at certain limit even when increasing the pressure. as was mentioned earlier these results are in agreement with the finding of gao jie 2014 [21]. the effect of pressure on permeate flux is great influence significantly. figure 10 show that permeate flux increase linearly from 13, 11.5 and 12.5 l/m 2 .hr at 1 bar, to 56, 52 and 54.5 l/m 2 .hr at 4 bar, for ni(ii), pb(ii) and cu(ii), with constant other parameters (concentration 100 mg/l, temperature 30 ºc ph 5.5, and flow 30 l/h). these results agree with dowfilmtec membranes manufacturer company (2012), were it was reported that the increasing in feed pressure, due to increase the removal of salts and heavy metals and the permeate flux will increase also, with other parameters constant. fig. 9: effect of pressure on h.m. removal percentage for ro (concentration=100 ppm, t=30 o c, ph=5.5, and f.f=30 l/hr) fig. 10: effect of pressure on permeate flux for ro (concentration=100 ppm, temperature=30 o c, ph=5.5, and feed flow rate=30 l/hr) 2.3. effect of temperature the effect of temperature on nickel (ii), lead (ii) and copper (ii), removal from aqueous solution by reverse osmosis system was studied by varying the temperature between 10 to 40 ºc. the results are shown in figure 11. figure shows the removal of nickel (ii), lead (ii) and copper (ii) ions as function of the temperature. the initial concentration was fixed as 100 mg/l, and initial ph was adjusted at 5.5. it can be seen that the removal percentage increased with increasing in temperature for all heavy metals. nickel has the highest rate of removal then lead and finally copper. it also shows that these increasing has stopped after 30 ºc and started to decrease. this is due to that membrane perfect work is at range of temperature from 20 to 30 ºc and its material building at these conditions. any increasing in temperature in these range leads to an imbalance in the membrane and to the expansion of the pores which allowing the transit of a large amount of ions to the product, which reduces the efficiency of the removal process. finally the large increase in temperature (more than 30 o c) leads to decrease in the h.m. removal, because high temperatures lead to a change in the material membrane and holes expansion allowing the entry of minerals and salts http://www.iasj.net/ removal of heavy metals from industrial wastewater by using ro membrane 132 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net dramatically with pure water evenly lower membrane efficiency and less removal process, then the large increase in temperature leads to membrane damage [22]. these results are in a good agreement with those obtained for dow-filmtec membranes manufacturer company (2006), which reported, that the removal of heavy metals and the permeate flux; will increase, when the temperature increases. figure 12, shows the effect of temperature on permeate flux for ro membrane, the values of permeate will increase clearly and large from 16, 14 and 15.6 l/m 2 .hr at 10 o c, to 55, 52 and 53 l/m 2 .hr at 40 o c, for ni(ii), pb(ii) and cu(ii) respectively. fig. 11: effect of temp.on h.m. removal for ro membrane , (concecntration=100 ppm, pressure=3 bar, feed flow rate=30 l/hr, and ph 5.5) fig. 12: effect of temperature on permeate flux for ro membrane, feed flow 30 l/hr, h.m. ions concentratin100 ppm, ph 5.5, and 3 bar pressure 2.4. effect of ph figure 13 shows that removal of heavy metals for ro system increases from 96.5%, 96.3% and 91.2% to values 98.2%, 97% and 95.3% for ni(ii), pb(ii) and cu(ii) ions respectively when the feed ph increases from 2 to 5.5. figure 14 shows that the highest value of permeate flux is 42, 41 and 41.5 l/m 2 .hr when the value of the ph between is (5-6) for ro membrane, and that it starts to decrease slightly with decrease in the value of the ph until it reached to 41, 40 and 40 l/m 2 .hr at ph 2 value for ni(ii), pb(ii) and cu(ii) respectively. the increase in h.m. ions removal and slightly increase in permeate flux of ro membrane can be attributed to the fact that the membrane is positively charged at ph < 7.0, but the positive charge decreases with increasing ph value, resulting in a low permeate of the anions; therefore in order to maintain the electroneutrality of the permeate solution, the removal of the ni(ii), pb(ii) and cu(ii) ions increases, and also the permeate flux increased [23], [24]. richards et al. (2011) reported that the removal of nickel ions across ro membrane is dependent on ph. increasing concentration of sodium sulphate in the feed solution leads to increase the ph of the feed solution. the positive charges force on the membrane will be lower as the ph increases towards the surface of the membrane, this leads to low nickel removal. gaojie (2014) reported that the solution ph has slightly influenced the removal of this heavy metal ion if the value of ph is less than 8. the highest removal of pb(no3)2 was obtained as high as 91.05 %, by using the pei cross-linked membranes. http://www.iasj.net/ ahmed h. algureiri and yossor r. abdulmajeed -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 133 fig. 13: effect of ph on h.m. removal for ro membrane, (concentration = 100 ppm, pressure= 3 bar temperature = 30 o c, and, and feed flow 30 l/hr) fig. 14: effect of ph on permeate flux for ro , feed flow 30 l/hr, h.m. concentration= 100 ppm, pressure= 3 bar, and temp.=30 o c 2.5. effect of feed flow rate increased feed flow rate leads to increase the flux. heavy metals are removed to a large extent because of removal of fouling layer from the surface of membrane, provided that is does not exceed a certain extent. this is because exceeding the limit leads to a lack of capacity of the filter membrane and possibly damage to the membrane. this depends on construction and the mechanical strength of the membrane. figures 15 shows the increasing of feed flow rate which led to decrease in permeate concentration. for h.m, the removal percentage are 95%, 93% and 92% at feed flow rate 10 l/hr, it increased to 98.4%, 98.2% and 95.9% at feed flow rate 40 l/hr for nickel (ii), lead (ii) and copper (ii) respectively. figure 16, shows the effect of increasing of feed flow rate on permeates flux for all metals. the permeate fluxes are 33, 32 and 32.5 l/m 2 .hr at feed flow rate 10 l/hr, it increase to 44, 42.5 and 43.5 l/m 2 .hr at feed flow rate 40 l/hr for nickel (ii), lead (ii) and copper (ii) respectively. from this figure, it was noted that increasing the feed flow rate prevents the concentration buildup in the solution at the vicinity of the membrane surface, and results in increasing of driving force. the greater shear generated at the surface due to a higher turbulence in membrane enhanced the rate of back-transport of polarized solute into the bulk of the solution, this could be a major reason for the decrease of permeate concentration [25]. the increase in the feed flow rate reduces concentration polarization value due to increase in turbulence near the membrane resulting in decreasing in the boundary layer thickness and solute concentration [26], [27], [28]. these results are in close agreement with j. fernandez, (2010), who that the permeate flow will increase with increase in the feed flow rate or the cross flow velocity. when cross flow velocity is 0.2 cm/s, the permeate flux is 0.80 x 10 6 m 3 /s·m 2 ; when cross flow velocity changes to 0.7 and 1.7 cm/s, the permeate flux is 1.08 and 1.39 x 10 -6 m 3 /s·m 2 , respectively. at the end of the run, when velocity returns to the initial value (0.2 cm/s), permeate flux returns to 0.80 x 10 -6 m 3 /s·m 2 . http://www.iasj.net/ removal of heavy metals from industrial wastewater by using ro membrane 134 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net fig. 15: effect of feed flow rate on flux for ro (concentration= 100 ppm, pressure= 3 bar, temperature = 30 o c, ph=5.5) fig. 16: effect of feed flow rate on flux for ro membrane (concentration=100 ppm, pressure= 3 bar, temperature=30 o c, and ph=5.5) conclusions from the present work the following conclusions can be drawn: 1. the ro membrane is very efficient to remove heavy metals from industrial wastewater which are produced in many industries. 2. h.m ions removal from industrial wastewater and permeability flux by ro is linearly proportional to applied pressure, ph, solution temperature and feed flow rate, but it is inversely proportional to feed concentration. 3. less pressure was used for the purpose of removing the h.m. ions from the industrial waste water, which meant less possible cost. references 1. surd gergely, arsenic "removal from drinking water by nanofiltration", doctoral (phd) thesis, new scientific results, (2001). 2. who, international year of fresh water. general assembly resolution a/res/ss/196, (2005). 3. barakat m. a. " new trends in removing heavy metals from waste water ", arabian journal of chemistry volume 4, issue 4, pages 361–377, (2011). 4. yu m.h. "soil and water pollution: environmental metals and metalloids", environmental toxicology: biological and health effects of pollutants, (2005). 5. mahiyab and mahesh c. chattopadhyaya , "contamination of heavy metals in aquatic media: transport, toxicity and technologies for remediation", chapter one, pages 1-24, ( 2014). 6. babel s., and kurniawan t.a., various treatment technologies to remove arsenic and mercury from contaminated groundwater: an overview. in: proceedings of the first international symposium on southeast asian water environment, bangkok, thailand, 24–25 october, pages 433–440, (2003). 7. duruibe j. o. ,ogwuegbu, m. o. c. and egwurugwu, j. n., heavy metal pollution and human biotoxic effects, (2007). 8. butticè claudio "nickel compounds". in colditz, graham a.the sage encyclopedia of cancer and society (second ed.). thousand oaks: sage publications, inc. pages 828–831, (2015). 9. das k. k., das s. n., and dhundasi s. a. "nickel, its adverse health effects and oxidative stress", environmental footprints of packaging, page 48, (2008). http://www.iasj.net/ http://www.sciencedirect.com/science/journal/18785352 http://www.sciencedirect.com/science/journal/18785352 http://www.sciencedirect.com/science/journal/18785352/4/4 http://www.icmr.nic.in/ijmr/2008/october/1005.pdf http://www.icmr.nic.in/ijmr/2008/october/1005.pdf ahmed h. algureiri and yossor r. abdulmajeed -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 135 10. salvato j.a., nemerow, n.l., agardy f.j., "noninfectious and noncommunicable diseases and conditions associated with the environment, including air, water, and food" environmental engineering (5th ed.), (2003). 11. epa,the united states environmental protection agency, issued recommendations regarding exposure to mercury in fish and shellfish, (2004). 12. scoullos michael j., vonkemangerrit h., thornton iain, and makuch, zen ,"mercury, cadmium, lead: handbook for sustainable heavy metals policy and regulation", (2001). 13. al-jlil s.a. "removal of heavy metals from industrial wastewater by adsorption using local bentonite clay and roasted date pits in saudi arabia", trends applied sci. res., 5: pages138-145, (2010). 14. fenglian fu, and qi wang, "removal of heavy metal ions from wastewaters" a review, journal of environmental management, vol. 92 no. 3, pages 407-418, (2011). 15. shahalam am, al-harthy a, alzawhry," a feed water pretreatment in ro systems: unit processes in the middle east", desalination 150(3), pages 235-245, ( 2002). 16. paul, d.r. "reformulation of the solution-diffusion theory of reverse osmosis", membrane science, vol. 241, pages 371-386, (2004). 17. dow-filmtec membranes manufacturer company, product information catalog, (2012). 18. fernandez j. and sempere, "experimental study of concentration polarization in across flow reverse osmosis system using holographic", desalination volume 257, p 36-45, issues1-3, (2010). 19. murthy z.v.p., and latesh chaudhari, "application of nanofiltration for the rejection of nickel ions from aqueous solutions and estimation of membrane transport parameters", journal of hazardous materials volume 160, issue 1, 15, pages 70–77, (2008). 20. lee i. , kuan y. and chern j., “equilibrium and kinetics of heavy metal ion exchange”, journal of the chinese institute of chemical engineers, vol. 38, pages 71-84 (2007). 21. gaojie, "nanofiltration membrane for lead removal", a thesis of msc. engineering national university of singapore, (2014). 22. denver colo, "reverse osmosis and nanofiltration", ebook publisher; american water works association, (2001). 23. abhaga r.m., wanib k.s., patilc v.s., pangarkara b.l., and parjane s.b. "nanofiltration for recovery of heavy metal ions from waste water –a review", international journal of research in environmental science and technology, pages 2934, (2013). 24. amir abbas izadpanah , and asgharjavidnia, "the ability of a nanofiltration membrane to remove hardness and ions from diluted seawater", water, volume 4, issue 2, (2012). 25. amir abdulrasoul, huu doan, ali lohi, and chil-hung cheng "mass transferadvancement in process modelling" ebook, (2015). 26. abou-nemeh i., and van peteghem a. p., "membrane recycling in the liquid surfactant membrane process", (1993). 27. barakat m.a. "removal of cu (ii), ni (ii) and cr (iii) ions from wastewater using complexationultrafiltration technique", journal of environmental science and http://www.iasj.net/ https://en.wikipedia.org/wiki/united_states_environmental_protection_agency https://en.wikipedia.org/wiki/united_states_environmental_protection_agency https://en.wikipedia.org/wiki/mercury_in_fish http://books.google.com/?id=9yzn-qgag_8c http://books.google.com/?id=9yzn-qgag_8c http://books.google.com/?id=9yzn-qgag_8c http://books.google.com/?id=9yzn-qgag_8c https://www.cheric.org/research/tech/periodicals/searchresult.php?articlesearch=shahalam%20am&searchtype=author https://www.cheric.org/research/tech/periodicals/searchresult.php?articlesearch=al-harthy%20a&searchtype=author https://www.cheric.org/research/tech/periodicals/searchresult.php?articlesearch=al-zawhry%20a&searchtype=author https://www.cheric.org/research/tech/periodicals/searchresult.php?articlesearch=al-zawhry%20a&searchtype=author https://www.researchgate.net/journal/0011-9164_desalination http://www.sciencedirect.com/science/journal/03043894/160/1 http://www.sciencedirect.com/science/journal/03043894/160/1 http://pubs.acs.org/action/dosearch?contribstored=abou-nemeh%2c+i. http://pubs.acs.org/action/dosearch?contribstored=van+peteghem%2c+a.+p. http://pubs.acs.org/action/dosearch?contribstored=van+peteghem%2c+a.+p. http://www.scialert.net/jindex.php?issn=1994-7887 http://www.scialert.net/jindex.php?issn=1994-7887 removal of heavy metals from industrial wastewater by using ro membrane 136 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net technology, volume 1, issue 3, pages 151-156, (2008). 28. velinjanimthethwa," investigation of polyethersulfone (pes) hollow fiber membrane for the treatment of acid mine drainage", johnson matthey technology review, (2014). http://www.iasj.net/ http://www.scialert.net/jindex.php?issn=1994-7887 47 ijcpe vol.11 no.4 (september 2010) iraqi journal of chemical and petroleum engineering vol.11 no.3 (september 2010) 4754 issn: 12010-4884 power generation from “pro” process using flat sheet tfc– ulp koch membranes adil al–hemiri, adel o. sharif * and saif t. manji department of chemical engineering, college of engineering, baghdad university *department of chemical engineering, surry university abstract the production of power using the process of pressure–retarded osmosis (pro) has been studied both experimentally and theoretically for simulated sea water vs. river water and deionized water under two cases: the first is for simulated real conditions of sea water and river water and second under low brine solution concentration to examine the full profile of the powerpressure. the influence of concentration polarization (cp) on water flux has been examined as well. keywords: pressure–retarded osmosis; renewable energy; tfc-ulp membrane; concentration polarization introduction osmosis hydro power is one of the recently attractive types of renewable energy. suggested only in the 1970s by sidney loeb (the coinventor of reverse osmosis) through utilizing the osmotic pressure in power generation using membranes. it is a natural process occurred when salt solution and fresh water are portioned in two chambers separated by a semi-permeable membrane, made for example of a biological membrane, e.g. of hog bladder, fresh water will permeate through the membrane. the driving force is capable of elevating the salt water level above the fresh water level, whereas the potential energy is obtained from the static water height. the process stops when the hydraulic pressure is equal to the potential osmotic pressure of the salt water. in theory, a stream flowing at 1 m3/s could produce 1 mw of electricity [1]. the global potential for pressure-retarded osmosis is calculated to be about 1600 twh/y and for europe 200 twh/y [2]. significant research efforts took place between mid 1970s to the early 1990s, but due to ineffective membranes, the key part of process, the construction of a pro power plant was not considered. in 1997, statkraft, one of the leading energy providers in norway, started their research on pro, they have constructed a pro prototype and claimed to construct commercial power plants in 2015[2]. concentration polarization a phenomenon of increasing the solute concentration at the low concentration side (concentrative external concentration polarization) and d concentration polarization) iraqi journal of chemical and petroleum engineering university of baghdad college of engineering power generation from pro process using flat sheet tfc–ulp koch membranes ijcpe vol.11 no.4 (december 2010) 48 and the build up or dilution of solute at the interface between the membrane active and support layer (internal concentration polarization). the first two types can be reduced greatly by pro membrane cell and experimental procedure the pro membrane cell is comprised of a two 3 in diameter qvf vessels capable of withstanding pressure up to 1.5 bar as shown in fig. 1. the membrane area is 45.6 cm2. providing agitation or circulation while the last type is strongly dependant on the resistance to solute transfer. this variable governs the rate of solute transfer within the support layer of the membrane and it is recommended to be as low as possible so that the solute will transport easily and hence prevent excessive concentration or dilution at the membrane inner interface [3]. the objective of the present study is describe the performance of pro process under simulated real conditions using flat sheet tfculp koch membrane and to derive a simple relation to predict theoretically that experimental membrane the membrane used for all experiments was provided by koch membrane systems. the membrane chemistry is uncertain but is believed to be composed of polyamide. brine and fresh water solutions deionized water was used to prepare the sodium chloride solutions. these solutes were used to represent sea water (brine solution) and river water (fresh water). the brine solution concentration taken are as 26.5 and 35 g/l nacl to resemble the actual concentration of nacl in sea water for the first and if the whole salts in sea water are represented by nacl for the second. the osmotic pressures of the various solutions were calculated using hysys® 3.1 software. per fig.1 schematic diagram of the pro membrane cell formance. this cell accepts flat sheet membranes. a plastic mesh spacer is provided on the fresh water side of to provide mechanical support to the membrane. the brine solution is flowing cocurrently to the fresh water and both solutions flow in closed circuits via plastic tubing. two centrifugal pumps from stuart turner ltd. (england) were used for circulating the solutions through the system. flowmeters measured the volumetric flow rates, which were fixed at 7 l/min for brine solution side and 5 for fresh water side with flow area around 11.4 cm2. both solutions flow at the same constant temperature 25  1.5oc. the detailed diagram of the pro system is given in fig. 2. adil a. a. al–hemiri, adel o. sharif, saif t. manji 49 ijcpe vol.11 no.4 (september 2010) fig. 2 schematic diagram of the pro system a pressure gauge followed by control valve is installed at the brine solution outlet on the membrane cell in order to pressurize the solution to any desired pressure. water and salt fluxes are determined by mass balance by measuring salt concentrations using calibrated conductivity meter provided by wtw (germany) in both solutions every 1 hour of experiment for a total of five hours. the power generated is calculated from the product of the pressure difference across the cell and water flux according to eq. 1 pjw w  (1) where w is the specific power generated in wm2, jw is the water flux in m3/ m2 (lee et al, 1981) results and discussion in pro operation, the brine solution side is pressurized as mentioned earlier; the positive difference between the brine solution and fresh water sides causes the water flux to decrease and the fo process to deviate towards reverse osmosis mode if the pressure difference does not surpass the osmotic pressure difference. figs. 3 and 4 show this behavior. fig. 3 measured water flux vs. pressure for 35 g/l brine solution concentration using di and river water at 7 and 5 l/min flow rates for brine solution side and fresh water respectively. all solutions are at 25 ± 1.5oc fig. 4 measured water flux vs. pressure for 26.5 g/l brine solution concentration using di and river water at 7 and 5 l/min flow rates for brine solution side and fresh water respectively. all solutions are at 25 ± 1.5oc the increase of the pressure difference is associated with drop in the water flux and is described by eq. 2  pajw  (2) where a is the water permeability coefficient, δπ is the osmotic pressure difference, and δp is the pressure difference [4]. power generation from pro process using flat sheet tfc–ulp koch membranes ijcpe vol.11 no.4 (december 2010) 50 the decrease in the water flux with increasing the pressure difference seems to lower the power produced but the increasing pressure compensates that drop due to increased momentum of the solution. fig. 5 measured specific power in watts/m2 vs. pressure for brine solutions of 35 and 26.5 and concentration and di water at 25 ± 1.5oc fig. 6 measured specific power in watts/m2 vs. pressure for brine solutions of 35 and 26.5, concentration and river water at 25 ± 1.5oc figs. 5 and 6 justify the increasing power generation resulted from increasing pressure difference regardless of the decrease in the water flux, however above figures show that the power produced is susceptible to further increase at higher pressures. the experimental observation of thorsen and holt (2009) and simple mathematical analysis provided elsewhere[3] reveal that the optimum operating pressure is about one-half the osmotic pressure difference show that the power pressure difference curve has a parabolic behavior were there is maximum point for the produced power and since such high pressure demanding operating condition is unattainable an alternative approach must be followed to predict experimentally the entire power – pressure curve. such approach can be reached by using brine solution of low concentration that possesses an osmotic pressure within the operating pressure range of the current membrane cell (up to 1 bar). a relevant concentration of brine solution is 1.5 g nacl/l which has an osmotic pressure of 1.17 bar and optimum pressure difference of 0.6 bar. this concentration is also studied for the cases of di water and simulated river water, see figs. 7 and 8. fig. 7 measured specific power and water flux against pressure difference for 1.5 g nacl/l brine solution and di water at 25c ± 1.5oc fig. 7 has matched the behavior of the earlier study5] in its parabolic form. the continuous increase of the pressure difference from fo conditions (where w has zero value) is accompanied by a decline in water flux and simultaneous increase in the specific power until a certain point in which wmax (peak of the adil a. a. al–hemiri, adel o. sharif, saif t. manji 51 ijcpe vol.11 no.4 (september 2010) curve) is reached. wmax from fig. 7 is about 0.00798 w/m2 at δp = 0.6 bar, this value is subjected to comparison with the theoretical value from [3] 4aw 2 m ax  (a.4) the water permeability coefficient for this system is found to be 2.335×10-12 m/s.pa and with δπ calculated from hysys 3.1 software wmax is 0.0078 w/m2 which appreciably agrees with the experimental value. fig. 8 measured specific power and water flux against pressure difference for 1.5 g nacl/l brine solution and river water at 25c ± 1.5 o c from fig. 8 wmax 0.0032 w/m 2 at δp = 0.4 bar with aapp = 2.096×10 -12 m/s.pa and δπ = 78,567.142 pa, theoretical value of w is found to be 0.003235 w/m2. the agreement between the experimental results and results of eq. a.4 is ascribed to the trivial polarization effects. the complete power – pressure difference curve using brine concentrations 35 and 26.5 g/l will be studied by the aid of eq. 2 which neglects any polarization effects and modified form of eq. 1 that allows for the concentration polarization to take place, see appendix a for details. table 1 values of permeability coefficient a, osmotic pressure difference and reflection coefficient for pro system system a (m/s.pa) ×1012 ∆ (bar)  35 g/l vs. 0.01 g/l 1.351 27.8 0.7494 26.5 g/l vs. 0.01 g/l 1.558 21.0 0.7913 35 g/l vs. 0.5 g/l 1.363 27.4 0.7032 26.5 g/l vs. 0.5 g/l 1.533 20.6 0.7275 the values of a are determined from the slopes in figs. 3 and 4, ∆ is calculated using hysys 3.1, and  (reflection coefficient) is found from fitting data in figs 5 and 6 to eq. a.5 figures 9 – 12 show a predicted profile of the specific power against pressure difference under pressure values up to 20 bars. the consideration of polarization effects in eq. a.5 has greatly reduced the power generation to about 1 w/m2 as in fig. 9 and 1.6 w/m2 as in figs 10 – 12. fig. 9 specific power against pressure difference for 35 g/l nacl brine solution and di water. specific power is predicted from eqs. a.2 and a.5 based evaluated parameters in table 1 power generation from pro process using flat sheet tfc–ulp koch membranes ijcpe vol.11 no.4 (december 2010) 52 fig. 10 specific power against pressure difference for 35 g/l nacl brine solution and simulated river water. specific power is predicted from eqs. a.2 and a.5 based evaluated parameters in table 1 fig. 11 specific power against pressure difference for 26.5 g/l nacl brine solution and di water. specific power is predicted from eqs. a.2 and a.5 based on evaluated parameters in table 1 fig. 12 specific power against pressure difference for 26.5 g/l nacl brine solution and simulated river water. specific power is predicted from eqs. a.2 and a.5 based on evaluated parameters in table 1 in fig. 13 a comparison between the experimental results of thorsen and holt[5] and eqs. a.2 and a.5 is made. the comparison shows the validity eq. a.5) and also shows the error encountered when concentration polarization effects are omitted. eq. a.5 has been in agreement with the experimental data to about 99.9 using chi square test. fig. 13 comparison between experimental results of thorsen and holt (2009) and the results of eqs. a.2 and a.5. () symbols denote for experimental results, solid line for eq. a.5 and dashed line for eq. a.2 adil a. a. al–hemiri, adel o. sharif, saif t. manji 53 ijcpe vol.11 no.4 (september 2010) conclusion osmosis hydro power seems to be very promising since it posses a capacity of 27 bar for sea water vs. river water but with the available membranes it is obvious that commercial production is beyond achieving yet. the reason is that the currently available membranes still have low water permeability coefficients. the concentration polarization cp have reduced the water flux greatly and hence power generation by a value about 1.6 w/m2, with value of  evaluated between 0.7 and 0.8 which represent the fraction that the total driving force ∆ has reduced to. the comparison of the modified eq. a.5 with the experimental work of thorsen and holt (2009) yielded an excellent agreement of 99%. nomenclature a water permeability coefficient (m.s-1.pa-1) jw water flux (l.m-2.h) p pressure of solutions (bar) w specific power (wm2) greek letters π osmotic pressure (pa) σ reflection coefficient superscripts * denote for either p or w with considering concentration polarization references 1-wick, g.l., and schmitt, w.r. (1977), "prospects for renewable energy from sea", marine technology society journal, 11. 2-statkraft (2006), "osmotic power — a huge renewable energy source, information material", www. statkraft.com. 3-lee, k.l., baker, r.w., and lonsdale, h.k. (1981), "membranes for power generation by pressure-retarded osmosis", journal of membrane science, 8. 4-mccutcheon, j.r. and elimelech, m. (2006), "influence of concentrative and dilutive internal concentration polarization on the flux behavior in forward osmosis", journal of membrane science, 284. 5-thorsen, t., and holt, t. (2009), "the potential for power production from salinity gradients by pressure retarded osmosis", journal of membrane science, 335. appendix a evaluation of reflection coefficient starting from eq. 1 pjw w  (1) suppose that water flux is calculated from  pajw  (a.1) substituting eq. a.1 into 1 to get  2ppaw  (a.2) the maximum attainable theoretical power (for negligible concentration polarization effects) is evaluated at δpoptimum obtained from differentiating eq. a.2 and equating to zero [3]. by donning so δpoptimum will be half the osmotic pressure difference 2poptimum  (a.3) therefore substituting (a.3) into (a.2) 4aw 2 m ax  (a.4) eq. a.4 presents an idealized approach for the calculation of the specific power since it is based on eq. a.1 which does not allow for effects of ecp and icp. therefore the introduction of the reflection coefficient σ into eq. a.1 is essential. by doing so result will be  2* ppaw  (a.5) recalculating the optimum pressure and the maximum specific power in similar manner 2p * optim um  (a.6) 4aw 2* m ax  (a.7) ijcpe vol.10 no.1 (march 2009) iraqi journal of chemical and petroleum engineering vol.10 no.1 (march2009) 23-27 issn: 1997-4884 extraction of atropine from datura innoxia using liquid membrane technique adel al-hemiri * and wasan o. noori * chemical engineering department college of engineering university of baghdad – iraq abstract selective recovery of atropine from datura innoxia seeds was studied. applying pertraction in a rotating film contactor (rfc) the alkaloid was successfully recovered from native aqueous extracts obtained from the plant seeds. decane as a liquid membrane and sulfuric acid as a stripping agent were used. pertraction from native liquid extracts provided also a good atropine refinement, since the most of co-extracted from the plant species remained in the feed or membrane solution. solid–liquid extraction of atropine from datura innoxia seeds was coupled with rf-pertraction in order to purify simultaneously the extract obtained from the plant. applying the integrated process, proposed in this study, a product containing 92.6% atropine was obtained. keywords: extraction, liquid membrane, pertraction, atropine, purification introduction atropine sulphate is used widely in medicine for resuscitation, anesthesia, ophthalmology, treat peptic ulcer and as an antidote for poisoning by organophosphate insecticides and nerve gases(1). atropine is found in many members of the solanaceae family. the most commonly found sources are atropa belladonna, datura innoxia, d. metel, and d. stramonium. other sources include members of the brugmansia and hyoscyamus genera. the nicotiana genus (including the tobacco plant, n. tabacum) is also found in the solanaceae family, but these plants do not contain atropine or other tropane alkaloids.(2) atropine can be extracted from the plant as free bases using basic aqueous solutions or as salts using acidified solutions. the obtained aqueous extracts contain many undesirable co-extracted species and the content of alkaloids is rather low. usually, the obtained native liquid extracts are purified using repeatedly performed solvent extraction operations. the alkaloids are extracted from basic solutions with an appropriate organic solvent. then, the organic solutions are stripped by acidic solutions and the alkaloids are recovered in the stripping solutions as salts. because of the relatively low distribution coefficients, for a complete recovery of the alkaloids, both extraction and stripping operations have to be repeated at least three to four times.(4) the difference in ph values between the two aqueous solutions is the driving force in this case.(5) one of the modern techniques of mixture separation is the application of liquid membranes. they reveal the ability of selective transport of mixture components in which a liquid membrane constitutes a separate phase which separates two other liquid or gas phases. this property of membranes makes them useful in the textile and food industries, in hydrometallurgy, medicine, biotechnology, environmental protection, in the separation of hydrocarbons and gases, and in the concentration and separation of amino acids, metal ions and other mixtures and suspensions.(3) the alkaloid, atropine, is an organic ester which may be prepared synthetically by combining tropine and tropic acid, but is usually obtained by extraction from some solanaceae plants.(6) this work was conducted to study the process of atropine recovery from its solution using a liquid university of baghdad college of engineering iraqi journal of chemical and petroleum engineering http://en.wikipedia.org/wiki/atropa_belladonna http://en.wikipedia.org/wiki/atropa_belladonna http://en.wikipedia.org/wiki/atropa_belladonna http://en.wikipedia.org/wiki/datura_inoxia http://en.wikipedia.org/wiki/datura_metel http://en.wikipedia.org/wiki/datura_stramonium http://en.wikipedia.org/wiki/datura_stramonium http://en.wikipedia.org/wiki/datura_stramonium http://en.wikipedia.org/wiki/brugmansia http://en.wikipedia.org/wiki/hyoscyamus http://en.wikipedia.org/wiki/nicotiana http://en.wikipedia.org/wiki/nicotiana_tabacum http://en.wikipedia.org/wiki/tropane extraction of atropine from datura innoxia using liquid membrane technique 24 ijcpe vol.10 no.1 (march 2009) membrane technique and to apply this procedure for selective recovery of the alkaloids from native aqueous extraction of datura innoxia seeds to produce atropine sulphate. experimental reagents and analytical methods used studies of atropine permeation through the liquid membrane were carried out using atropine aqueous solutions. the atropine was extracted from datura innoxia seeds (collected in 2004, region of dyala, iraq) applying solid–liquid extraction. decane (99%, bdh) as a liquid membrane and sulphuric acid (poch) as a stripping agent were used. ammonia solution (chemsupply, 30%), and sulphuric acid were used to adjust the acidity of the aqueous solutions. atropine concentration in the aqueous solutions was measured by uv spectroscopy, λ = 257 nm (λ being the absorbance) and calculated on the basis of atropine (hyoscyamine). for this analysis sulphuric acid and ammonia, as well as diethyl ether (fluka ag, buchs sg), heptane (hopkin & williams), hexane (aldrich), diiso propyl ether (bdh) were used. since the amount of co-extracted species in the acceptor solutions was found to be insignificant, atropine concentration in these solutions was determined directly by uv-spectroscopy, also the acidity of the aqueous solutions was measured by means of a laboratory ph meter (maurituius). experimental equipment and procedures the liquid membrane in a rotating film contactor (rfc) offers more intensive hydrodynamics and therefore, a faster pertraction process. pertraction in a rfc is a special bulk liquid membrane technique in which two aqueous solutions (feed and stripping solutions) form mobile films on the surfaces of vertical rotating discs, partially immersed in the organic membrane liquid. this pertraction technique provides stable and efficient continuous operation, avoiding the phase dispersion or phase intermixing .(7) the purpose of rotation of hydrophilic discs is to increase the mass transfer effectiveness, the flow of two crossing streams produced in the membrane is in such a way that a vortex flow is achieved. this causes a renewal of the contact area and considerable intensification of mass transfer.(8) pertraction studies were carried out in a 3000 ml laboratory rotating film contactor made of perspex (plexiglas®) (fig.1). the apparatus body contained two extraction stages of equal volume. the space in the lower part of each stage is separated into two compartments, for the feed and stripping solutions, respectively. compartments containing the same aqueous solution are interconnected. the upper part of both compartments contains the membrane liquid. four discs, 0.5mm thick and 0.17m in diameter, mounted vertically on a common shaft, rotated in each compartment, providing continuous renewal of the aqueous films, covering the discs, as well as the stirring of all three liquids. the lower part of each disc (up to one-third of the disc diameter) is immersed in the corresponding aqueous solution and the larger, upper part is immersed in the organic membrane liquid, as shown in (fig.2). the discs surfaces being hydrophilic, intended to homogenize the attached aqueous films. hence, the aqueous solutions occupying the lower parts of each compartment form mobile liquid films on the corresponding disc surfaces, which are in direct contact with the common membrane liquid, filling the upper part of apparatus. the two stages could be connected in a way permitting co-, counter-current or batch operation modes. the latter was chosen in our experiments. to homogenize the aqueous solutions and to provide samples from each solution, both liquids were re-circulated by means of two peristaltic pumps. a variable rotation speed electric motor provided constant shaft rotation. for the pertraction studies, the following three liquid phase system was used:  feed (donor) solution (f): 250 ml aqueous solution  membrane solution (m): 500 ml  stripping (acceptor) solution (a): 250 ml fig. 1 scheme of rotating film contactor [4] adel al-hemiri and wasan o. noori 25 ijcpe vol.10 no.1 (march 2009) results and discussion the results obtained for the extraction of atropine from datura innoxia are discussed below. effect of type of liquid membrane figure (2) presents a comparison of the liquid membranes used. all five lm to some extent show similar behavior. during experimentation the white crystals of atropine were observed to start forming after about 15 minutes of operation. from fig.(2) it can be seen that decane and heptane gave the highest concentration of atropine after one hour of operation and then the concentration was steady or dropped only slightly. however, when using heptane the concentration of atropine decreased, after one hour, because the irreversible reaction lead to atropine transport from acceptor solution to feed solution. therefore, if heptane is to be used the reaction must be stopped after one hour. as can be seen that the other solvents (hexane, propyl ether and ethyl ether) gave lower concentration values and there was some loss of these solvents during operation due to their high volatility, a problem is not encountered with decane. finally, it should be noted that in the present work decane and heptane were used (for the first time) along with other solvents used by earlier workers (viz; hexane, diiso propyl ether and ethyl ether). and decane was found to be the best solvent for the duty considered, as shown below. 0 15 30 45 60 75 90 105 0 20 40 60 80 100 120 140 c o n c e n tr a ti o n o f a tr o p in e ( g /m 3 ) time (min)decane heptane hexane propyl ether ethyl ether fig. 2 effect of liquid membrane used effect of ph of the aqueous acceptor solution from fig(3), it can be seen that the best results obtained at ph=2.1 . this is because the atropine must be isolated as salt by using dilute acid but if acceptor solution is more diluted which leads to small amount of (h2so4) molecular in acceptor aqueous solution therefore, being not enough to produce large amount of atropine sulphate. on the other hand when stronger acid is used also gives smaller amount of atropine sulphate. 0 15 30 45 60 75 90 105 0 20 40 60 80 100 120 140 c o n c e n tr a io n o f a tr o p in e ( g /m 3 ) time (min) ph=2.1 ph=1.5 fig.3 effect ph of acceptor solution effect of amount of seed when doubling the amount of seeds (7.2g instead of 3.6g) and keeping the conditions constant. this produced higher values of atropine sulphate in comparison with the employed half amount of seeds as shown in fig (4). wherewithal these results increased of seeds weight lead to increased amount of atropine in feed solution in the same time in membrane as well as in the stripping phase. it is reasonable to observe increases in extraction by increasing the atropine concentration in the feed phase. this is true for all extraction processes. 0 20 40 60 80 100 120 140 160 0 50 100 150 c o n c e n tr a ti o n o f a tr o p in e ( g /m 3 ) time (min) decane (w=3.6) fig.4 effect of amount of seeds extraction of atropine from datura innoxia using liquid membrane technique 26 ijcpe vol.10 no.1 (march 2009) effect of ph of feed solution it is observed that the ph of the aqueous donor (feed) phase played an important role on the extraction of atropine values. from fig (5) it can be seen that the best result when ph equal 9.4 0 20 40 60 80 100 120 140 7 8 9 10 11 12 13 a tr o p in e c o n c e n tr a ti o n ( g /m 3 ) ph of feed solution fig.5, effect ph of feed solution in addition, the experiments were carried out under the best conditions obtained, unless otherwise stated, these conditions are: ph of feed solution 9.4, rpm=10, weight of seeds=3.6gm, ph of acceptor solution 2.1 and two stage unit. yield datura innoxia contain atropine, hyoscine as well as small amount of hyoscyamine and other alkaloids. generally the content of alkaloids in datura is (0.01 3 %) from dry weight, this percentage depended on plant type, environmental and agriculture process.(9),(10) from herbal india constitution the major chemical compounds found in datura innoxia is 33% atropine, 66% hyoscine and 1% hyoscyamine oxide and other compounds.(11) therefore the maximum concentration of atropine in seeds is theoretically (3% * 0.33 * 3.6gram/ 250cm3) equal o.1425 * 10-3 (gram/ cm3) = (142.5 gram/m3), but from our experiments on the local plant the concentration was found to be (132.54 gram/m3) and the following table shows the amount of atropine in feed and in product, as well as the yield(12). solvent atropine in feed gram/ m 3 atropine in product gram/ m 3 yield % decane (two stage) 130.45 120.855 92.645 decane (one stage) 130.45 100.91 77.35 heptane 130.45 95.148 72.94 hexane 130.45 31.42 24.086 diiso propyl ether 130.45 48.116 36.88 ethyl ether 130.45 27.292 20.92 conclusions pertraction in a rotating film contactor is a suitable technique for atropine recovery from its solutions, including native liquid extracts of datura innoxia . the process of atropine recovery from the plant seeds using decane as a liquid membrane is very selective. 1. the highest atropine yield (92.6%) was achieved when using two stages. 2. it was found that the decane is the best solvent as liquid membrane. (12) 3. best ph value of acceptor solution is 2.1 and of feed solution are 9.4. 4. it was found that the atropine conversion increases with increasing amount of datura seeds feed. 5. the hydrophilic discs of stainless steel gave good extraction. 6. increasing the number of stages caused increased atropine extraction. adel al-hemiri and wasan o. noori 27 ijcpe vol.10 no.1 (march 2009) references 1. atropine sulfate definition of atropine sulfate in the free online encyclopedia, http://encyclopedia2.thefreedictionary.com/atropine+ sulfate 2. atropine wikipedia, the free encyclopedia, http://en.wikipedia.org/wiki/atropine (23/7/2008). 3. w.kaminski, w.kwapinski, (2000) "applicability of liquid membranes in environmental protection", polish journal of environmental studies vol. 9, no. 1 , 37-43. 4. k. dimitrov, d. metcheva, l. boyadzhiev (2005) " integrated processes of extraction and liquid membrane isolation of atropine from atropa belladonna roots", separation and purification technology 46, 41–45. 5. lubomir boyadzhiev and valentina dimitrova (2006) "extraction and liquid membrane preconcentration of rosmarinic acid from lemon balm (melissa officinalis l.)", separation science and technology, 41, 877–886. 6. atropine (international programme on chemical safety evaluation, 2002), http://www.inchem.org/documents/antidote/antidote/atro pine.htm 7. k. dimitrov , s. alexandrova , a. saboni , e. debray , l. boyadzhiev (2002) "recovery of zinc from chloride media by batch pertraction in a rotating film contactor", journal of membrane science 207 (2002) 119–127 8. wladyslaw kaminski and witold kwapinski ,(2001)"hydrodynamics and mass transfer in liquid membrane with crossing stream", ind. eng. chem. res., 40, 1234-1238 9. verpoorte . r. and al fermann , a. w. (2000)"metabolic engineering of plant secondary metabolism", kluwer academic publishers , dordrecht, boston , london . 10. kitamura . y . ; sato . m . and miura .h . (1992) . "differences of atropine esterase activity between intact roots of various tropane alkaloid – producing plants". phytochemistry. oxford : pergamon press. apr. v. 31 (4) p. 1191-1194. 11. chakravarty , h.l. (1976).plant wealth of iraq. a dictionary of economic plants ,vol.1 , botany directorate, ministry of agriculture and agrarian reform, iraq. 12. wasan o.n. (2008) "extraction of bio-active substances from botanical using integrated solvent extraction and liquid membrane techniques" msc thesis, chemical engineering, university of baghdad. http://encyclopedia2.thefreedictionary.com/atropine+sulfate http://encyclopedia2.thefreedictionary.com/atropine+sulfate http://en.wikipedia.org/wiki/atropine http://www.inchem.org/documents/antidote/antidote/atropine.htm http://www.inchem.org/documents/antidote/antidote/atropine.htm iraqi journal of chemical and petroleum engineering vol.15 no.1 (march 2014) 3342 issn: 1997-4884 optimization of activated carbon preparation from date stones by microwave assisted k2co3 activation asmaa f. abbas and muthanna j. ahmed chemical engineering department-college of engineering-university of baghdad-iraq abstract the preparation of activated carbon (ac) from date stones by using microwave assisted k2co3 activation was investigated in this paper. the influence of radiation time, radiation power, and impregnation ratio on the yield and methylene blue (mb) uptake of such carbon were studied. based on box-wilson central composite design, two second order polynomial models were developed to correlate the process variables to the two responses. from the analysis of variance the significant variables on each response were identified. optimum coditions of 8 min radiation time, 660 w radiation power and 1.5 g/g impregnation ratio gave 460.123 mg/g mb uptake and 19.99 % yield. the characteristics of the ac were examined by pore structure analysis, and scanning electron microscopy (sem).the bet surface area and total pore volume were indentified to be 1144.25 m²/g and 0.656 m³/g, respectively. keywords: activated carbon, methylene blue, microwave, optimization, adsorption introduction activated carbon (ac) is a carbonaceous material possessing a higher porosity due to which it is commonly used in variety of application, concerned principally with the removal of chemical species by adsorption form the liquid or gas phase [1]. however, ac is expensive which limits its large-scale application. a potential method to reduce its cost is to produce it from low-cost material such as agricultural by-products, which has attracted an increasing research interest in recent years [2]. from the literature, many studies have been carried out to prepare low cost ac from agricultural wastes such as cotton stalk [3], grapevine rhytidome [4], sewage sludage [5], mangosteen peel [6], and pineapple peel [7]. the preparation of ac involves of two stages, namely pyrolysis and activation [8]. in the first stage, suitable carbon precursors are carbonized under inert atmosphere at moderate temperature to release volatile matters and produce chars with rudimentary pore structures. subsequently, the resulting chars are subjected to partial gasification at higher temperature (usually above 900˚c) with oxidizing gases, to produce activated carbons with welldeveloped and accessible internal porosities [9].nevertheless, in some cases, the thermal process may take long processing time, involves high energy consumption, requires larger equipment size and generates improper heating rate, thereby resulting in a iraqi journal of chemical and petroleum engineering university of baghdad college of engineering optimization of activated carbon preparation from date stones by microwave assisted k2co3 activation 34 ijcpe vol.15 no.1 (march 2014) -available online at: www.iasj.net detrimental effect on the quality of the prepared activated carbons [10]. furthermore, there is a considerable risk of overheating or even thermal runaway of local sample, leading to the complete combustion of the carbon [11]. therefore, it is necessary to find a rapid and easy route for the preparation of ac. although microwave heating is today a mature technique which finds wide applications in the area of material science, food processing and analytical chemistry [12], there are relatively few studies in this field. microwave heating has the advantages of rapid temperature rise, uniform temperature distribution and saving of energy over conventional thermal method [13]. methylene blue, the most commonly used substance in the dying process was chosen as the model adsorbate in this study, due to its potential risk towards the environmental pollution and ecosystems. currently no study has been done on optimization of the production of activated carbon from date stones using the response surface methodology (rsm) approach. rsm has been found to be a useful tool to study the interaction of two or more factors [14]. a standard rsm design called box-wilson central composite design is suitable for fitting a quadratic surface and it helps to optimize the effective parameters with a minimum number of experiments, as well as to analyze the interaction between the parameter [15]. rsm has just recently been used for the optimization of activated carbon production from rattan sawdust [14], tamarind wood [16] and turkish lignite [17] by chemical activation whereas oil palm empty fruit bunch [18] and coconut husk [19] by physiochemical activation method. the goal of this work is to optimize the preparation conditions of ac from date stones for the removal of mb dye from aqueous solution. the effects of radiation time, radiation power and impregnation ratio are also studied simultaneously to obtain a high mb uptake using the box-wilson central composite design. materials and method materials date stones were used as the precursor for the preparation of ac. the date stones as received were first washed with water to get rid of impurities, dried at 110 ˚c for 24 h, crushed using disk mill, and sieved. fraction with particle size of 300-600 μm was selected for the preparation. potassium carbonate (purchased from didactic company, espana) of purity 99.9 % was used as an adsorbate. mb has a chemical formula of c16h18n3scl, with molecular weight of 319.86 g/mol. all other chemical used such as hydrochloric acid were from analytical grades. preparation of activated carbon a weighed amount (2g) of dried date stones was mixed with 10 ml of k2co3 solution at various impregnation ratios (0.5-2.5 g/g) for 24 h at room temperature. the samples were next placed in an oven (model ih-100, england) at 110 ˚c until completely dried and stored in desiccators. the dried samples were activated by using a quartz glass reactor (2.5 cm diameter x 12.5 cm length). the reactor was sealed at bottom and open from the top end to allow for the escape of the pyrolysis gases. a modified microwave heating oven (mm717 cpj, china) was used for preparation as shown in fig. 1. the upper surface of oven had a removable cover connected to a stainless steel pipe of 5 mm inside diameter from which pyrolysis gases were exit. the reactor was placed inside the oven and held at different radiation powers (540-700 w) for asmaa f. abbas and muthanna j. ahmed -available online at: www.iasj.net ijcpe vol.15 no.1 (march 2014) 35 different radiation times (4-12 min). after activation, the sample was withdrawn from the oven and allowed to cool. for isolation of residual k2co3 activator, the sample was mixed with 0.1m hcl solution at 10 mg/l solid to liquid ratio. the mixture was left overnight at room temperature, and then filtered and subsequently the sample was repeatedly washed with distilled water to remove residual organic matters and alkalis, until the ph of filtrate reached 6.5-7.0. after that, the sample was dried at 110 ˚c for 24 h, and subsequently was weighed. finally the sample was stored in tightly closed bottles. fig. 1, schematic diagram of microwave unit for preparation of activated carbon process performance the performance of chemical activation process was determined by the product yield, along with its uptake for mb. the yield and mb uptake are determined as follows. yield the yield is defined as the ratio of final weight of the obtained product after washing and drying to the weight of dried precursor initially used. the yield of ac was calculated based on the following equation: 100 x w w (%) yield o f …(1) where wf and wo are the weight of final ac product (g) and the weight of dried date stones (g), respectively. mb uptake the mb uptake or adsorption capacity of prepared ac was determined by performing batch adsorption tests in 100 ml erlenmeyer flasks where 50 ml of mb aqueous solutions with initial concentration of 250 mg/l was placed in each flask. the ph of the solution was 6.85 without any ph adjustment. 0.005 g of each of the prepared ac, with average particle size of 0.25 mm, was added to each flask and kept in a shaker of 200 rpm at room temperature for 24 h to reach equilibrium. aqueous samples were taken from the solutions and the concentrations were analyzed. all samples were filtered prior to analysis in order to minimize interference of the carbon fines with the analysis. the concentrations of mb in the supernatant solutions were determined using uv-visible spectrophotometer (shimadzu uv-160a) at its maximum wave length of 664 nm. the mb uptake at equilibrium, qe (mg/g), was calculated by the following equation: w v ) c (c q e o e  …(2) where co and ce are initial and equilibrium concentrations of the mb (mg/l), respectively, v is the volume of the aqueous mb solution (l), and w is the weight of ac used (g). experimental design in order to organize the experiments of ac preparation from date stones, a standard rsm design, known as boxwilson central composite design was adopted. this design can reduce the number of experimental trails needed to evaluate multiple parameters and their interactions [20]. generally, the optimization of activated carbon preparation from date stones by microwave assisted k2co3 activation 36 ijcpe vol.15 no.1 (march 2014) -available online at: www.iasj.net box-wilson design consists of 2 n factorial points, 2n axial points, and one center point, where n is the numbers of variables. in order to design the experiments, the operating range of variables must be specified, thus: radiation time x1 (4-12 min), radiation power x2 (540-700 w), and impregnation ratio x3 (0.5-2.5 g/g). the total number of experiments n is computed according to the following equation: 12n2n n  …(3) the relationship between the coded variable and the corresponding real variable is as follows: n* xx xx x mincenter centeractual coded            …(4) characterization of activated carbon the surface area, pore volume, and average pore diameter of ac prepared under optimum preparation condition were determined by using micromeritics asap 2020 volumetric adsorption analyzer which based on the continuous flow method originally developed by nelsen &eggertsen. for bet surface area analysis, a mixture of nitrogen balance helium is passed through the reference channel of the tcd detector to the sample housed within a flow-through glass cell and finally into the tcd analytical channel. the signal produced by the tcd detector is collected by the microprocessor control board, integrated and stored in the memory file. microscopic appearance of ac and date stones was studied by scanning electron microscope (sem). microscopic image of ac and precursor were obtained by sem (vega3 tescan). results and discussion model fitting and statistical analysis the experimental values of yield and mb uptake of ac are fitted with a second order polynomial mathematical model. the general form of this model as a function of x1, x2, and x3 is represented by the following equation: 2 3x9b 2 2 x8b 2 1 x7b 3x2x6b3x1x5b 2x1x4b3x3b2x2b1x1boby    …(5) a nonlinear least-squares regression program based on gauss-newton method was used to fit eq. 5 to the coded data and experimental responses. the fitted response surface of eq. 5 is: 2 3 x775462.0 2 2 x189653.1 2 1 x310993.1 3 x 2 x0.18184 3 x 1 x24511.0 2 x 1 x26816.0 3 x20738.3 2x89331.31x69503.480434.151y     …(6) 2 3 x1106.34 2 2 x14966.2 2 1 x4624.11 3 x 2 x0.17579 3 x 1 x000389.0 2 x 1 x21509.0 3 x151651.2 2x220162.41x774731.14909.4512y     …(7) the analysis of variance (f-test) was used for testing the significance of each effect in eqs. 6 and 7. an estimate of the variance sb 2 is obtained by dividing the experimental error variance sr 2 by the sum of squares of each effect σx 2 , as follows: 2 2 2 2 r2 b σx n))/(ne( σx s s   …(8) the significance of effects may be estimated by comparing the values of the ratio (b 2 /sb 2 ) with the critical value of the f-distribution at 95 % confidence level (f0.95=6.61). if the ratio b 2 /sb 2 > 6.61 then the effect is asmaa f. abbas and muthanna j. ahmed -available online at: www.iasj.net ijcpe vol.15 no.1 (march 2014) 37 significant. from this result, it appears that the interaction effects are not significant and the radiation time has the greatest effect on the yield while radiation power has the greatest effect on mb uptake of prepared ac, 744.051 and 274.209, respectively. the best response functions in terms of actual variables are then conveniently written as follows: 2 3 x463893.2 2 2 x000579.0 2 1 x0.252326 3 x9309.12 2x80217.01x22825.62609.3881y    …(9) 2 3 x2372.103 2 2 x001146.0 2 1 x184567.2 3 x42911.313 2x5131206.11x776387.35879.4302y    …(10) eqs. 9 and 10 were used to construct graphical representations of yield and mb uptake versus each variable within the variables ranges used in forming the models. process optimization at optimum conditions, the prepared ac should have a high yield and high mb uptake. however, it is difficult to optimize both these responses under the same condition because the interest region of variables is different, when mb uptake increases, carbon yield decrease and vice versa. therefore, the optimum conditions have been determined depending on achieving high mb uptake. the optimum operating conditions has been determined by differentiating both sides of eq. 10 for each independent variable and equating the derivative to zero [21]. thus, the optimum conditions corresponding to a maximum mb uptake are 8 min radiation time, 660 w radiation power, and 1.5 g/g impregnation ratio. at these conditions, 460.12 mg/g mb uptake with 19.99 % yield were reported experimentally. effect of process variables effect of radiation time the effect of radiation time on yield and mb uptake of prepared ac at different radiation powers and optimum impregnation ratio is shown in figs. 2 and 3, respectively. fig. 2 shows that the yield of ac decreases with increasing radiation time. an increase in radiation time from 4 to 12 min at optimum conditions of 660 w radiation power and 1.5 g/g impregnation ratio leads to a decrease in yield of ac from 26.26 to 8.69 %. a steep decrease occurs after 10 min, this is probably due to rapid evolution of volatile materials to form stable compounds as explained by foo and hameed [22]. they showed that a steep decrease in yield occurs after 7 min for production of ac from coconut husk by microwave koh activation. mb uptake of ac increases with radiation time and reaches at maximum of 452.66 mg/g at 8 min and optimum conditions of 660 w and 1.5 g/g. thereafter it decreases, as shown in fig. 3. the decrease in mb uptake with activation above 8 min is probably due to turn off mesopores to macropores which are not effective for mb adsorption, as explained by foo and hameed [23]. figs. 2 and 3 show that there are no interactions between radiation time and radiation power. fig. 2, effect of radiation time on yield (impregnation ratio of 1.5 g/g) optimization of activated carbon preparation from date stones by microwave assisted k2co3 activation 38 ijcpe vol.15 no.1 (march 2014) -available online at: www.iasj.net fig. 3, effect of radiation time on mb uptake (impregnation ratio of 1.5 g/g) effect of radiation power the yield and mb uptake of prepared ac versus radiation power at different impregnation ratios and optimum radiation time is shown in figs. 4 and 5, respectively. it can be seen from fig. 4 that, as the radiation power increases from 540 to 700 w at optimum conditions of 8 min radiation time and 1.5 g/g impregnation ratio, the yield decreases from 26.33 to 12.81 %. this may be due to the loss of the volatile materials with increasing power. beyond 660 w a lower rate of yield decrease was noticed where a stable structure is formed. fig. 5 shows that the mb uptake increases with radiation power up to 660 w, then decreased. an increase in power from 540 to 660 w at optimum conditions of 8 min radiation time and 1.5 g/g impregnation ratio causes an increase in mb uptake from 436.17 to 452.66 mg/g. the decrease in adsorption ability with further increase in power might be due to the sintering effect at high power, followed by shrinkage of the char, and realignment of the carbon structure which resulted in reduced pore areas as well as volume, as explained by deng et al. [23] for mb adsorption on ac prepared from cotton stalk by microwave assisted koh activation, who reported an optimum radiation power of 680 w. fig. 4, effect of radiation power on yield (radiation time of 4 min) fig. 5, effect of radiation power on mb uptake (radiation time of 4 min) effect of impregnation ratio figs. 6 and 7 show the effect of impregnation ratio on yield and mb uptake of prepared ac, respectively at different radiation times and optimum radiation power. it is noticed that, as the impregnation ratio increases the yield decreases, as shown in fig. 6. an increase in impregnation ratio from 0.5 to 2.5 g/g at 8 min radiation time and 660 w radiation power leads to a decrease in yield from 21.42 to 10.34 %. this decrease is due to the continuous removal of tar material from the pores. the decreasing rate of yield is lowered beyond an impregnation ratio of 1.5 g/g where a stable structure is formed. this behavior agrees with results obtained by sudaryanto et al. [25] for ac production from cassava peel by chemical activation with potassium hydroxide. fig. 7 shows that the mb uptake of ac increases with impregnation ratio up to 1.5 g/g, then asmaa f. abbas and muthanna j. ahmed -available online at: www.iasj.net ijcpe vol.15 no.1 (march 2014) 39 decreased. the increase in impregnation ratio from 0.5 to 1.5 g/g at 8 min and 660 w leads to an increase in mb uptake from 345.70 to 452.66 mg/g. more increase in the concentration of k2co3activator perhaps leads to the excessive dehydration and destruction of mesopores and turning them to larger pores which reduces the adsorption efficiency, as explained by foo and hameed [26] for adsorption of mb on ac prepared from oil palm empty fruit bunch by microwave assisted koh activation. they reported an optimum impregnation ratio of 1 g/g. fig. 6, effect of impregnation ratio on yield (radiation power of 660 w) fig. 7, effect of impregnation ratio on mb uptake (radiation power of 660 w) characterization of activated carbon bet surface area and pore volume the bet surface area, total pore volume and average pore diameter of ac prepared at optimum conditions are found to be 1144.25 m²/g, 0.656 m³/g and 3.004 nm, respectively. these values higher than that reported by foo et al. [28] who show the bet surface area and total pore volume of activated carbon from date stones by koh activation were 865 m 2 /g and 0.468 m 3 /g, respectively. the average pore diameter of 3.004 nm indicates that the ac prepared is in the mesopores region according to the iupac classification [27]. the chemical activation process has contributed to the high surface area and total pore volume of the prepared ac. table 1 shows the comparison between the other precursors of prepared ac of structure textural. surface morphology figs. 8a and b show sem images of date stones and ac. it can be found that the surface of date stones is dense, planar, constricted and blocked by deposited tray substance. however, the microwave irradiation sample demonstrated a well-developed and uniform surface, forming an orderly pore structure. the development of porosity is associated with gasification according to the following reduction reactions [29]: co 2k 2c ok co ok cok 3co 2k 2c cok 2 22 32 32    it was assumed that metallic potassium k formed during the gasification process would diffuse into the internal structure of carbon matrix widening the existing pores and created new porosities. fig. 4b also shows that the surface of prepared carbon contains some cavities which are resulted from the evaporation of impregnated k2co3 derived compounds, leaving the space previously occupied by the reagent. theses cavities provide channels for the adsorbate molecules to access the micropores and mesopores inside a carbon particle. optimization of activated carbon preparation from date stones by microwave assisted k2co3 activation 40 ijcpe vol.15 no.1 (march 2014) -available online at: www.iasj.net table 1, comparison of pore structures of carbons prepared from various agricultural wastes by microwave heating precursor time (min) power (w) ratio (g/g) chemical agent sbet (m 2 /g) vt (cm3/g) ref. date stones 8 660 1.5 k2co3 1144.25 0.656 this work date stones 8 600 1.75 koh 856 0.468 [28] oil palm empty fruit bunch 15 360 0.75 koh 807.54 0.450 [26] cotton stalk 8 400 50(vol%) h3po4 652.82 0.476 [3] fig. 8, sem micrographs (10 kx) of date stones (a) and ac (b) conclusion activated carbons were prepared from date stones by microwave assisted k2co3 activation. 460.1234 mg/g mb uptake with corresponding yield of 19.99 % were obtained at optimum conditions of 8 min radiation time, 660 w radiation power, and 1.5 g/g impregnation ratio. also, the surface area, total pore volume and average pore size of ac were 1144.25 m²/g, 0.656 m³/g and 3.004 nm, respectively .box-wilson central composite design was adopted for arrangement of preparation experiment. two second order polynomial models were successfully used to correlate the process variables to the two responses. acknowledgement we gratefully acknowledge department of chemical engineering and university of baghdad for assist and support of this work. references 1r. c. bansal, j. b. donnet, f. stoecki, (1988), active carbon, marcel dekker, inc, new york. 2o. ioannidu, a. zabaniotou, (2007), agricultural residues as precursors for activated carbon production – a review, renew. sustain. energy rev. 11, 1966-2005. 3hui deng, genlin zhang, xiaolinxu, guanghui tao, jiulei dai, (2010), optimization of preparation of activated carbon from cotton stalk by microwave assisted phosphoric acid-chemical activation, journal of hazardous materials, 182,217-224. 4mahtab hejazifa , saeid azizian , hassan sarikhani , qiang li , dongyuan zhao , (2011), microwave assisted preparation of efficient activated carbon from grapevine rhytidome for the removal of methyl violet from asmaa f. abbas and muthanna j. ahmed -available online at: www.iasj.net ijcpe vol.15 no.1 (march 2014) 41 aqueous solution , journal of analytical and applied pyrolysis , 92, 258-266. 5q. h. lin , h. cheng , g. y. chen , (2012), preparation and characterization of carbonaceous adsorbents from sewage sludge using a pilotscale microwave heating equipment , journal of analytical and applied pyrolysis , 93,113-119. 6k. y. foo. b. h. hameed, (2012), factors affecting the carbon yield and adsorption capability of the mangosteen peel activated carbon prepared by microwave assisted k2co3 activation, chemical engineering journal 1806-74. 7k. y. foo. b. h. hameed, (2012), porous structure and adsorptive properties of pineapple peel based activated carbon prepared via microwave assisted koh and k2co3activation, microporous and mesoporous material, 148,191-195. 8t.h. liou, (2010), development of mesoporous structure and high adsorption capacity of biomass based activated carbon by phosphoric acid and zinc chloride activation, chem. eng. j. 158(2), 129-142. 9j. achrya , j.n. sahu , c.r. mohanty , b.c. meikap , (2009) , removal of lead (ii) from wastewater by activated carbon developed from tamarind wood by zinc chloride activation , chem. eng. j. 149 (1-3), 249-262. 10i. polaert , l. estel ,r. huyghe , m. thomas , (2010) , adsorbents regeneration under microwave irradiation for dehydration and volatile organic compounds gas treatment , chem. eng. j.162 (3), 941-948. 11p. nowicki,m. skrzypczak , r. pietrzak , (2010) , effect of activation method on the physiochemical properties and no 2 removal abilities of sorbents obtained from plum stones (prunusdomestica ) , chem. eng. j. 162, 723-729. 12m. komorowska, g.d. stefanidies, t. van gerven, a. l. stankiewicz, (2009), influence of microwave irradiation on a polyesterification reaction, chem. eng. j. 15 (3), 859-866. 13j. guo, a.c. lua, (2000), preparation of activated carbons from oil-palm-stone chars by microwave-induced carbon dioxide activation, carbon, 38, 1985-1993. 14a. a. ahmad, b. h. hameed, a. l. ahmed, (2009), removal of disperses dye from aqueous solution using waste derived activated carbon: optimization study, j. hazard. mater.170, 612-619. 15a. m. m. varagas , c. a. garcia , e. m. reis , e. lenzi , w.f. costa , v. c. almeida , (2010), naoh activated carbon from flamboyant (delonixregia) pods ; optimization of preparation condition using central composit rotatable design , chem. eng. j. 162,43-50. 16j. n. sahu, j. acharya, b. c. meikap, (2010),optimization of production condition for activated carbon from tamarind wood by zinc chloride using response surface methodology, bioresour. technol. 10, 1974-1982. 17f. karacan, v. ozden, s. karacan, (2007), optimization of manufacturing condition for activated carbon from turkish lignite by chemical activation using response surface methodology, appi. therm. eng. 2, 1212-1218. 18b. h. hameed, i. a.w. tan, a. l. ahmed, (2009), preparation of oil palm empty fruit bunch. based activated carbon for removal of 2, 4, 6-trichlorophenol: optimization using response surface optimization of activated carbon preparation from date stones by microwave assisted k2co3 activation 42 ijcpe vol.15 no.1 (march 2014) -available online at: www.iasj.net methodology. j. hazard. mater.164, 1316-1324. 19i. a. w. tan, a. l. ahmed, b. h. hameed, (2008), optimization of preparation conditions for activated carbons from coconut husk using response methodology, chem. eng. j. 137, 462-470. 20tan i. a. w., ahmed a. l., hameed b. h., (2008) , preparation of activated carbon from coconut husk: optimization study on removal of 2, 4, 6-trichlorophenol using response surface methodology, j. hazard. mater, 153, 709-717. 21edger t. f., himmelblau d. m, (2001), optimization of chemical process, 2 nd ed, mcgraw-hill chemical engineering series. 22k. y. foo, b. h. hameed, (2012), coconut husk derived activated carbon via microwave induced activation: effects of activation agents, preparation parameters, and adsorption performance, chemical engineering journal, 184, 57-65. 23k. y. foo, b. h. hameed, (2012), microwave-assisted preparation and adsorption performance of activated carbon from biodiesel industry solid reside: influence of operational parameters, bioresour technology 103, 373381. 24deng h., li g., yang h., tang j., (2010), preparation of activated carbon from cotton stalk by microwave assisted koh and k2co3 activation, chem. eng. j., 163, 373-381. 25sudarynto y., hartono s. b., irawaty w., ismadji s., (2006), high surface area activated carbon prepared from cassava peel by chemical activation, bioresour. technol., 97, 734-739. 26k. y. foo, b. h. hameed, (2011), preparation of oil palm (elaeis) empty fruit bunch activated carbon by microwave-assisted koh activation for the adsorption of methylene blue, desalination, 275, 302-305. 27iupac. ivpac marua of symbols and terminology. pure appi.chem 1973; 31: 587. 28k. y. foo, b. h. hameed, (2011), preparation of activated carbon from date stones by microwave induced chemical activation: application for methylene blue adsorption, chemical engineering journal, 170, 338-341. 29d.w. mckee, (1983), mechanisms of the alkali metal catalyzed gasification of carbon, fuel, 62, 170-175. iraqi journal of chemical and petroleum engineering vol.17 no.4 (december 2016) 4355 issn: 1997-4884 indirect electrochemical oxidation of phenol using rotating cylinder reactor ammar s. abbas 1 , mohammad h. hafiz 2 and rasha h. salman 3 1,3chemical engineering department college of engineering – university of baghdad 2engineering college – iraqia university abstract indirect electrochemical oxidation of phenol and its derivatives was investigated by using mno2 rotating cylinder electrode. taguchi experimental design method was employed to find the best conditions for the removal efficiency of phenol and its derivatives generated during the process. two main parameters were investigated, current density (c.d.) and electrolysis time. the removal efficiency was considered as a response for the phenol and other organics removal. an orthogonal array l16, the signal to noise (s/n) ratio, and the analysis of variance were used to test the effect of designated process factors and their levels on the performance of phenol and other organics removal efficiency. the results showed that the current density has the higher influence on performance of organics removal while the electrolysis time has the lower impact on the removal performance. multiple regressions was utilized to acquire the equation that describes the process and the predicted equation has a correlation coefficient (r 2 ) equal to 98.77%. the best conditions were found to get higher removal efficiency. removal efficiency higher than 95% can be obtained in the range of c.d. of 96-100 ma/cm 2 and electrolysis time of 3.2 to 5 h. the behavior of the chemical oxygen demand (cod) mineralization denotes to a zero order reaction and the rate of reaction controlled by active chlorine reaction not by mass transfer of phenol towards the anode. key words: phenol removal, cod removal, manganese dioxide, rotating cylindrical electrode, taguchi method. introduction petroleum refining is the physical, chemical, and thermal separation of crude oil into its main fractions and obtaining finished petroleum products through a series of separation and conversion steps. petroleum refinery industry transforms crude oil into more than 2500 refined products, and large quantities of water are required for the purpose of attaining these products; about 80-90 % of the supplied water comes out as wastewater [1, 2]. the petroleum refinery wastewater is one of the worst contaminators of surface and ground waters and can cause detrimental environmental problems and tends to increase toxicity and creates the major environmental impact. in general, the effluent generated in the exploitation, university of baghdad college of engineering iraqi journal of chemical and petroleum engineering indirect electrochemical oxidation of phenol using rotating cylinder reactor 44 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net production and refining of oil contains high concentrations of organic compounds with cod levels of approximately (300–600 ppm) and inorganic pollutants, sulphides, ammonia, chloride, 20–200 ppm of phenol, 1–100 ppm of benzene, heavy metals (0.1–100 ppm of chrome and 0.2–10 ppm of lead), suspended solids, grease and chemical additives. consequently, these effluents need to be treated prior to discharge or reuse [3, 4]. major consideration is paid to pollutants with an aromatic structure because they tend to be more toxic than their aliphatic complements. aromatic compounds arise in many segments of the process industry, such as petroleum refineries, textiles, synthetic chemical plants, pulp and paper, detergent, plastics, pharmaceutical factories, pesticide, and herbicide. water effluents containing aromatic chemicals are refractories, and are often toxic to biological treatment processes. phenols are aromatic compounds enclosing one or more hydroxyl groups attached to the aromatic ring. phenols are one of the widely distributed toxic substances and have been classified as one of the 65 priority pollutants which are considered to be harmful to humans and the environment and their presence must be limited to 0.1 mg/l [5– 7]. conventional wastewater treatment involves a series of mechanical, physical, chemical, and biological operations and processes, but these processes are not always preferred and have many limitations. electrochemical technologies for removal of organics from petroleum refinery wastewater and wastewater of other industries have a great attention hence they offer many distinctive advantages relative to the other technologies such as; compatibility with environment, adaptability, energy efficiency, selectivity, safety, flexibility to automation, and cost effectiveness [8, 9]. in electrochemical process, the destruction of organic pollutants may take place by either direct or indirect oxidation process. in the direct anodic oxidation process, the pollutants are first adsorbed on the anode surface and then removed by the anodic electron transfer reaction. it is well known that removal of phenol by direct electrochemical oxidation process causes a rapid fouling to the surface of employed electrode (such as graphite, platinum, ruthenium dioxide, lead dioxide, and tin dioxide) due to formation of a blocking polymer layer created by the polymerization of the phenoxy radicals produced in the initial stages of the reaction. this results in decreasing the active surface area of the electrode and a termination of the reaction within minutes [10]. in indirect oxidation process, strong oxidants such as hypochlorite/chlorine, hydrogen peroxide, ozone are electrochemically produced. the pollutants are then removed in the bulk solution by oxidation reaction of the produced oxidant. the effectiveness of the electrochemical oxidation process and its performance enhanced by the addition of high concentrations of chloride ions in water; beside it can decrease its energy consumption. all the oxidants are produced in situ and are utilized immediately. the electrochemical method is one of the methods of oxidizing phenols which making it possible to attain an oxidant at the site of consumption and rapidly regulate the parameters of electrolysis. since oxidation of phenol in the absence of mineral salts continues gently, the oxidizing process is conducted against the background of chlorides. the chief oxidizing agent in electro-oxidation in chloride solutions was activated chlorine formed in the http://www.iasj.net/ ammar s. abbas, mohammad h. hafiz and rasha h. salman -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 45 water being treated as a result of anodic oxidation of chloride ions and subsequent chlorine hydrolysis. activated chlorine presence speeds up the treatment process. sodium chloride (nacl) is a very good choice hence it is easily available at reasonable cost, it is able to increase the electrical conductivity of the wastewater to a suitable level [11– 13]. during the process of electrochemical oxidation of phenol, several aromatic and aliphatic intermediates are generated which they are more poisonous than phenol. consequently, cod removal is very difficult in comparison with phenol removal because of the complex nature of cod and hence there are some intermediates can form, it is better to take the cod as a response as an alternative of phenol concentration. moreover, longer electrolysis time is required for cod reduction compared to phenol removal. the energy consumption can be increased due to the extension of electrolysis time. so, the removal of organic contaminants in a very short time period makes the electrochemical method satisfactory for the industrial wastewater treatment applications. it can be concluded that an electrochemical method is successful for cod removal if it is successful for phenol removal, and vice versa [3, 14]. most common anode materials used in wastewater treatment are graphite, lead/lead dioxide, nickel, platinum, sno2-sb, and boron doped diamond (bdd). these electrodes have some disadvantages, graphite is unstable or it could be oxidized to co or co2. using pbo2 electrode is not favorable due to the need for lead removal from the treated solution. sno2-sb electrode has problems with deactivation and short service life. high anodic stability and a wide potential window for water discharge are one of the most advantages of bdd; however, the limitation of using it efficiently for wastewater treatment is still restricted by its high cost, mechanical resistance problems and difficulties in finding a suitable substrate on which to deposit the thin diamond layer. the investigation of cheaper materials with analogous performances have attracted a great effort among these, manganese oxides (mnox) materials represent an attractive family for electrode manufacture, this is due to their unique structures, good electrochemical properties, good electrocatalytic properties, the relatively low cost, low toxicity, environmentally friendly character in comparison with other transition metal oxides, the natural abundance, and chemical stability [10, 13, 15]. the aim of the present study are applying galvanostatic conditions in the process of indirect electrochemical oxidation of phenol and its derivatives from a simulated wastewater and examining the performance of this batch electrochemical reactor by using the taguchi method. the purposes of taguchi approach were studying the effect of two parameters (c.d., and electrolysis time) on the removal efficiency using l16 orthogonal array experimental design, and determining the degree of significance of the studied factors on the removal efficiency using analysis of variance (anova). experimental work 1. materials and system 150 mg of phenol was dissolved in 1 l of distilled water for the preparation of simulated wastewater (which is equivalent to 315 mg/l of cod), and 1 g/l of nacl, 0.1 m h2so4 (as a supporting electrolyte) added also, all chemicals used in experiments http://www.iasj.net/ indirect electrochemical oxidation of phenol using rotating cylinder reactor 46 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net were of the reagent grade. the electrochemical cell consists of (2 liters) capacity glass reservoir fixed on a hot plate magnetic stirrer (labinco, model l-81), dc power supply (uni-t: utp3315tf-l) was used with outlet voltage (0-30 v) and output current (0-5 a). a cylindrical mno2 on graphite substrate (with 30 cm 2 as the effective area) was used as the anode. the cathode was a graphite hollow cylinder with an inside diameter of 8 cm and an outside diameter of 10 cm and 15 cm length fixed in the glass electrolytic bath. the electrical connection of the rod was achieved by a cylindrical brass ring, and the rod insulated from the holder by a piece of teflon. to rotate the anode with the required rotation speed, an electrical gear box stirrer (heidolph) was used with electronic tachometer and the speed of rotation was 200 rpm. a schematic diagram of the electrochemical process is shown in figure 1. fig. 1: schematic diagram of the electrochemical system 2. procedure  after the preparation of electrolytic solution, the cathode electrode which was the hallow cylinder graphite was dipped into the electrolytic solution, and the mno2 anode electrode was fixed to the agitator and dipped into the electrolytic solution.  the electrodes were connected to the dc power supply and a constant current density was applied to the electrolytic cell for a specified time and rotation speed of the electrical stirrer.  the samples were collected during the electrolysis process, and the temperature of the electrolyte was maintained about 25°c ±1. taguchi design approach was used to study the effect of the two parameters on the removal efficiency of phenol and any other by products which was measured by the cod at the end of each experiment by using a cod reactor (lovibond water testing, http://www.iasj.net/ ammar s. abbas, mohammad h. hafiz and rasha h. salman -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 47 rd 125 model) where 2 ml of the sample was added to a vial containing a standard amount of a potassium dichromate oxidizing mixture. the phenol and any other organics exist in the sample would be oxidized for 2h at 150 °c. the vial was allowed to cool to room temperature and then a photometersystem md200 (lovibond water testing) was used to measure the cod. 3. taguchi design full factorial design is a traditional optimization approach which involves a large number of experiments because it would take all possible combinations for studied variables. this approach is not useful because of time consuming and high operational cost [16]. another method in the experimental design is called taguchi method. taguchi method can be used to determine the effect of factors on distinctive properties and the optimal conditions of the studied parameters. the determination of the possible combinations of factors and identification of best combinations can be easily achieved by this method [17, 18]. the taguchi method uses a distinct design of orthogonal arrays. the orthogonality means that factors can be evaluated individually from one another; the effect of one factor cannot be affected with the evaluation of the influence of another factor [19]. the variables considered for the study are time (t), and c.d. since they have a powerful effect on the performance of electro-oxidation process [20, 21], these variables and their levels are illustrated in table 1, where four levels of each parameter were chosen. the suitable orthogonal array which allows the investigating of the effect of the considered parameters and the interaction between them for these levels would be l16; either (4 2 ), and the experiments under the same conditions were carried out as shown in table 1. each row in this table represents one experimental run. the four values of time and c.d. were studied at four values (2, 3, 4, and 5 h) and (25, 50, 75, and 100 ma/cm 2 ), respectively, corresponding to levels 1, 2, 3, and 4. table 1: coded & real values of l16 orthogonal array exp. no. coded values real values a b c.d. (ma/cm 2 ) time (h) 1 1 1 25 2 2 1 2 25 3 3 1 3 25 4 4 1 4 25 5 5 2 1 50 2 6 2 2 50 3 7 2 3 50 4 8 2 4 50 5 9 3 1 75 2 10 3 2 75 3 11 3 3 75 4 12 3 4 75 5 13 4 1 100 2 14 4 2 100 3 15 4 3 100 4 16 4 4 100 5 results and discussion taguchi design of experiment (doe) technique was applied at the present study to examine the most manipulating factors on cod removal efficiency, to find the best conditions of c.d., and time of electrolysis for organic pollutants removal. the l16 orthogonal array results illustrated in table 2; the experimental data were analyzed using minitab 17 software. http://www.iasj.net/ indirect electrochemical oxidation of phenol using rotating cylinder reactor 48 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net table 2: results of experimental design for organics removal, *cod initial value= 315 ppm exp. no. real values response c.d.(ma/cm 2 ) time(h) cod(ppm) removal efficiency (%) s/n 1 25 2 290 7.9365 23.5461 2 25 3 246 21.9048 27.3517 3 25 4 188 40.3175 30.1682 4 25 5 115 63.4921 31.9016 5 50 2 236 25.0794 28.4772 6 50 3 199 36.8254 32.2829 7 50 4 122 61.2698 35.0994 8 50 5 75 76.1905 36.8327 9 75 2 154 51.1111 31.6877 10 75 3 116 63.1746 35.4933 11 75 4 88 72.0635 38.3098 12 75 5 59 81.2698 40.0432 13 100 2 58 81.5873 34.6706 14 100 3 19 93.9683 38.4763 15 100 4 5 98.4127 41.2928 16 100 5 3.15 99.0000 43.0261 1. main effect plots the relationship between the studied parameters and output response can be visualized by main effect plot. figure 2 represents the main effect plot for the cod removal efficiency (%) using indirect electrochemical oxidation process (i.e., electrooxidation of organics in the presence of nacl), where 1 g/l of nacl was added to the electrolytic solution. it is well-known that the phenol removal is achieved by the reactive chlorine species such as chlorine and hypochlorous acid or hypochlorite ion (cl2, hocl and ocl − ) that react very fast with organics chiefly by the reactions in solution. free chlorine is the dominant oxidizing agent in acidic conditions, while in slightly alkaline conditions hypochlorite, chloride ions and hydroxyl radicals are all produced in appropriate concentrations [22]. the hocl generation increases as the c.d. also increases, therefore the organic removal efficiency increased. the organic removal also governed by the electrolysis time, the generation of hocl increases with time increasing. 2. signal –tonoise a basic signalto-noise (s/n) ratio is a quantitative measure that employed by taguchi method to determine the optimum removal conditions, besides it used for the evaluation of the variation of the response around the mean value due to experimental noise, so an optimal response with smaller variations can be obtained. the terms ‘signal’ to ‘noise’ ratio signify the desirable (mean for the output characteristic) and undesirable values (standard deviation (sd) for the output characteristic) for the output response, respectively. the analysis of means and s/n ratio that recommended by taguchi uses a theoretical approach that includes plotting the effects and visually recognizing the factors that appear to be significant, without the need for anova analysis, so the analysis would be very simple [23, 24] . the choice principles of s/n ratio depend on the objective of the design; the s/n ratios are different according to the type of output response. generally, a better signal http://www.iasj.net/ ammar s. abbas, mohammad h. hafiz and rasha h. salman -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 49 attained when the noise is smaller, so that a larger s/n ratio yields better results. therefore, the optimal level of process parameters is the level with the highest s/n ratio. usually, there are three types of s/n ratios, higher is best (hb), nominal-is-best (nb), and lower is best (lb) to choose from. for each level of the process parameters, the s/n ratio computed based on the s/n analysis [25]. fig. 2: main effect plot for organics removal efficiency in order to maximize the removal efficiency the bigger is better approach is implemented, in which the s/n ratio is calculated as presented in equation 1 [26]: ⁄ [ (∑ ) ] …(1) where yi is the response of each experiment, and n is the repetition number of each experiment. s/n ratio can reflect both the average and the variation of the quality characteristics; so, it merges several repetitions into one value which reflects the amount of variation present [16]. table 2 shows the s/n ratios calculated based on equation 1 for all the responses of experiments. the effect of each control parameter on the response obtained from the response table 3 for s/n which represented graphically in figure 3. this table contains ranks based on delta statistics, which compare the relative magnitude of effects. the highest average for each factor minus the lowest average for the same called the delta statistics. rank 1 is assigned to the highest delta value, rank 2 to the second highest delta value; and so on, so ranks are assigned based on delta values [27]. therefore, the values of delta in this table indicate that the current density has the greatest influence on the organic removal followed by time, and speed of rotation. in the main effect plot of s/n ratio, the x-axis point to the value of each process parameter at three levels and the y-axis is the response s/n values. the main effect plots used to determine the optimum conditions of the design, so obtaining the optimal value of the responses. http://www.iasj.net/ indirect electrochemical oxidation of phenol using rotating cylinder reactor 50 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net according to the main effect plot of s/n ratio, the best conditions for the organic removal are current density of 100 ma/cm 2 , and electrolysis time of 5 h. these conditions are the conditions of run (16), so no confirmation step is required in this analysis. the cod removal efficiency was 99 %. table 3: response table for signal to noise ratios (bigger is better) level c.d. time 1 28.24 29.60 2 33.17 33.40 3 36.38 36.22 4 39.37 37.95 delta 11.12 8.36 rank 1 2 fig. 3: main effect plots of sn ratios for removal efficiency of phenol and other organics 3. analysis of variance (anova) the utilization of anova by taguchi method is a very good implement to find out which are statistically the most significant parameter and to find out the value of percentage contribution of each factor to a change in the dependent variable. analysis of variance on the experimental results accomplished to determine the variation source during the process of indirect electrochemical oxidation of the organics; then the identification of the effect order of factors on the organics removal would relatively be easy [28]. the anova was established based on the degree of freedom (df), the sum of the square (ss), the percentage contribution of each parameter, adjusted sum of squares (adj ss), adjusted mean of square (adj ms), f-value, and p-value. the statistical expressions of these terms can be defined in many books and studies dealing with experiments design and analysis [29]. any factor has a high percent contribution; then a small variation in its magnitude will have a great influence on the performance. the percentage contribution for each parameter defied as the portion of a total observed variance in the experiment for each significant parameter. when the value of this http://www.iasj.net/ ammar s. abbas, mohammad h. hafiz and rasha h. salman -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 51 percentage contribution is greater, then it contributes to the final results more than other factors [26]. the results of the anova summarized in table 4. as in the s/n ratio analysis, it is obvious that the significance of the factors succeeds in the following order of importance: c.d.> electrolysis time. the data given in table 4 showed that the contributions of the two factors i.e. c.d., and time of electrolysis were 66.03 and 28.37%, respectively. it is clear that current density has the greatest contribution on organic removal followed by electrolysis time. statistically, the f value for each studied parameter is the ratio of the mean of squared deviations to the mean of squared error. for the present condition, the value of f (1, 15) with 95% confidence level is 4.2417 [30]. generally, when f>4, it means that the studied parameter is significant and the variation of it makes a big change on the performance [18]. it is obvious from the results of f value in table 4 that all the two studied parameters are significant since all of them have f> 4. the significance of each factor on response is determined by p-value. if p-value value ˂ 0.05 (for a confidence level of 95%) indicates that the factor is significant. p-values in this study ˂ 0.05 (for a confidence level of 95%); indicate that all model terms are significant. measuring the proportion of the total variability explained by the model is called the r 2 static, is close to (1) for our response. the same result acquired with respect to the adjusted r 2 , which used for considering the model significance since it is convenient when comparing the model with different number of terms. the results illustrate that adj.r 2 is not suggestively different from the ordinary r 2 . residual plots used to calculate the adequacy of the model. the residual plots for phenol and other organic removal are presented in figure 4. the descriptions of each residual plot for the present experiments known as followed:  normal probability plot point out that the data are normally distributed and the variables are manipulating the response. there are no outliers existing in the data.  histogram proves that the data are not skewed and no outliers exist.  residuals versus fitted values indicate that the variance is constant and a non-linear relationship exists. ideally, the points should fall randomly on both sides of zero.  residuals versus order of the data indicate that there are systematic effects in the data due to time or data collection order. table 4: analysis of variance for organic removal efficiency source df seq ss contribution adj ss adj ms fvalue pvalue c.d. 3 7839.6 66.03% 7839.6 2613.20 35.35 0.000 time 3 3368.7 28.37% 3368.7 1122.89 15.19 0.001 error 9 665.3 5.60% 665.3 73.92 total 15 11873.6 100.00% general linear model s 8.59764 r-sq 94.40% r-sq(adj) 90.66% press 2102.60 rsq(pred) 89.29% http://www.iasj.net/ indirect electrochemical oxidation of phenol using rotating cylinder reactor 52 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net fig. 4: residual plots of organics removal efficiency 4. multiple regression analysis the multiple regression model for cod removal efficiency is as follows: …(2) where x1 is current density and x2 is electrolysis time. the predicted equation had the squared value of the correlation coefficient (r 2 ) equal to 98.77% with error percentage equal to 2 %. contour plot presented in figure 5 clarifies that the best conditions for getting removal efficiency ˃ 95% are c.d. within the range 96-100 ma/cm 2 , and time of 3.2-5 h. using 100 ma/cm 2 gives removal efficiency ˃ 95% within 3.2 h, while using 90 ma/cm 2 gives it within 5h. fig. 5: contour plot of removal efficiency versus c.d. (ma/cm 2 ) and time (h) time c .d . 5.04.54.03.53.02.52.0 100 90 80 70 60 50 40 30 > – – – – < 40 40 60 60 80 80 90 90 95 95 removal% contour plot of removal% vs c.d., time http://www.iasj.net/ ammar s. abbas, mohammad h. hafiz and rasha h. salman -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 53 the decay in cod affected intensely by the concentration of chloride ion (cl ) and by the operational variables (current and voltage). the effects of current densities on cod are presented in figure 6. phenol removal succeeded by the reactive chlorine species (i.e., hypochlorous acid (hocl)), which is the dominant oxidizing agent in acidic conditions. the cod decreased and removal percentage increased with the c.d. increasing. as the c.d. increases from 30 to 90 ma/cm 2 , the cod decreases linearly from 315 to 110.61, and 18.34 ppm, respectively. while the removal efficiency increases from 64.88 to 94.17 % respectively. the linear behavior of the cod reduction under different current densities refers to a zero order reaction and the rate of reaction controlled by active chlorine reaction not by mass transfer of phenol towards the anode. these results are in agreement with previous studies done by other workers [15, 21, 31]. fig. 6: cod vs. electrolysis time at different current densities for rotating mno2 cylinder electrode, codo=315 ppm conclusion removal of phenol has been studied in the present work by indirect electrochemical oxidation and a does (derived from the taguchi approach technique) was applied to observe the best experimental conditions, c.d. and time designated as the studied parameters, and these factors varied at four levels with an orthogonal array of l16, which could examined with the bigger is better as a quality character. taguchi analysis suggested that c.d. has the largest influence on the performance of electrochemical removal of phenol and other organics. based on the results of the anova, it can be established that the significance of the factors has the following order of importance: c.d. followed by the electrolysis time. based on taguchi multiple regression model, the best conditions for removal efficiency of cod equal to 99%, were c.d. of 100 ma/cm 2 and electrolysis time of 5 h. references 1. i. d. santos, m. dezotti, and a. j. b. dutra, “electrochemical treatment of effluents from petroleum industry using a ti/ruo2 anode,,” chem. eng. j., vol. 226, pp. 293–299, 2013. 2. n. v. fomchenko, i. n. shcheblykin, and v. v. biryukov, “cleaning concentrated refinery wastewaters from sulfides, phenols, and ammonia 0 50 100 150 200 250 300 350 0 1 2 3 4 5 6 c o d ( p p m ) time (h) 30 (ma/cm^2) 45 (ma/cm^2) 60 (ma/cm^2) 75 (ma/cm^2) 90 (ma/cm^2) http://www.iasj.net/ indirect electrochemical oxidation of phenol using rotating cylinder reactor 54 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net nitrogen,”chem. pet. eng., vol. 35, no. 7, pp. 399–402, 1999. 3. y. yavuz, a. s. koparal, and ü. bak, “treatment of petroleum refinery wastewater by electrochemical methods,” desalination, vol. 258, pp. 201– 205, 2010. 4. d. s. ibrahim, p. s. devi, and n. balasubramanian, “electrochemical oxidation treatment of petroleum refinery effluent,” int. j. sci. eng. res., vol. 4, no. 8, pp. 1–5, 2013. 5. s. randazzo, o. scialdone, e. brillas, and i. sirés, “comparative electrochemical treatments of two chlorinated aliphatic hydrocarbons. time course of the main reaction by-products,” j. hazard. mater., vol. 192, no. 3, pp. 1555–1564, 2011. 6. x. y. li, y. h. cui, y. j. feng, z. m. xie, and j. d. gu, “reaction pathways and mechanisms of the electrochemical degradation of phenol on different electrodes,” water res., vol. 39, no. 10, pp. 1972–1981, 2005. 7. v. smith de sucre and a. p.watkinson, “anodic oxidation of phenol for waste water treatment,” can. j. chem. eng., vol. 59, pp. 52–59, 1981. 8. a. a. batoeva, m. r. sizykh, a. a. ryazantsev, m. s. khandarkhaeva, and d. g. aseev, “electrochemical oxidation of phenols,” russ. j. appl. chem., vol. 80, no. 8, pp. 1365–1368, 2007. 9. k. rajeshwar and j. g. ibanez, environmental electrochemistry : fundamentals and applications in pollution sensors, no. may. elsevier science & technology books, 1997. 10. p. l. hagans, p. m. natishan, b. r. stoner, and w. e. o’grady, “electrochemical oxidation of phenol using boron-doped diamond electrodes,” j. electrochem. soc., vol. 148, no. 7, pp. e298–e301, 2001. 11. k. k. s. vimal chandra srivastava, digvijay patil, “parameteric optimization of dye removal by electrocoagulation using taguchi methodology,” int. j. chem. react. eng., vol. 9, no. a8, pp. 1–19, 2011. 12. s. y. bashtan and v. a. bagrii, “electrochemical oxidation of phenol on metaloxide electrodes,” j. water chem. technol., vol. 34, no. 1, pp. 24–27, 2012. 13. d. rajkumar, j. g. kim, and k. palanivelu, “indirect electrochemical oxidation of phenol in the presence of chloride for wastewater treatment,” chem. eng. technol., vol. 28, no. 1, pp. 98–105, 2005. 14. y. yavuz and a. s. koparal, “electrochemical oxidation of phenol in a parallel plate reactor using ruthenium mixed metal oxide electrode,” journal of hazardous materials, vol. 136, no. 2. pp. 296– 302, 2006. 15. p. h. brittocosta and l. a. m. ruotolo, “phenol removal from wastewaters by electrochemical oxidation using boron doped diamond ( bdd ) and ti/ti0.7ru0.3o2,” brazilian j. chem. eng., vol. 29, no. 04, pp. 763–773, 2012. 16. y. ma, h. hu, d. northwood, and x. nie, “optimization of the electrolytic plasma oxidation processes for corrosion protection of magnesium alloy am50 using the taguchi method,” j. mater. process. technol., vol. 182, no. 1– 3, pp. 58–64, 2007. 17. k. do kim, d. n. han, and h. t. kim, “optimization of experimental conditions based on the taguchi robust design for the formation of nano-sized silver particles by chemical reduction method,” chem. http://www.iasj.net/ ammar s. abbas, mohammad h. hafiz and rasha h. salman -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 55 eng. j., vol. 104, no. 1–3, pp. 55– 61, 2004. 18. g. barman, a. kumar, and p. khare, “removal of congo red by carbonized low-cost adsorbents: process parameter optimization using a taguchi experimental design,” j. chem. eng. data, vol. 56, no. 11, pp. 4102–4108, 2011. 19. y.-c. chen, p.-j. tsai, and j. mou, “determining optimal operation parameters for reducing pcdd / f emissions ( i-teq values ) from the iron ore sintering process by using the taguchi experimental design,” environ. sci. technol., vol. 42, no. 14, pp. 5298– 5303, 2008. 20. p. h. britto-costa, r. b. alencarsouza, and l. a. m. ruotolo, “electrochemical degradation of phenol at bdd anodes in chloride medium,” pp. 1–8. 21. z. tasic, v. k. gupta, and t. f. bor, “the mechanism and kinetics of degradation of phenolics in wastewaters using electrochemical oxidation,” int. j. electrochem. sci., vol. 9, pp. 3473–3490, 2014. 22. j. pires, d. p. barreto, e. vieira, m. m. oliveira, d. ribeiro, j. f. de souza, and c. a. martínez-huitle, “electrochemical mediated oxidation of phenol using ti/iro2 and ti/pt-sno2-sb2o5 electrodes,”j. electrochem. sci. eng., vol. 4, no. 4, pp. 259–270, 2014. 23. y. q. wang, j. h. byun, b. s. kim, j. il song, and t. w. chou, “the use of taguchi optimization in determining optimum electrophoretic conditions for the deposition of carbon nanofiber on carbon fibers for use in carbon/epoxy composites,” carbon n. y., vol. 50, no. 8, pp. 2853–2859, 2012. 24. m. vega, r. pardo, e. barrado, m. a. de la fuente, and j. l. del valle, “application of the taguchi experimental design to the optimisation of a photo-oxidation procedure for trace metal analysis in freshwater,” fresenius. j. anal. chem., vol. 350, no. 3, pp. 139–144, 1994. 25. j. f. martínez-villafañe and c. montero-ocampo, “optimisation of energy consumption in arsenic electro-removal from groundwater by the taguchi method,” sep. purif. technol., vol. 70, no. 3, pp. 302– 305, 2010. 26. a. zirehpour, a. rahimpour, m. jahanshahi, and m. peyravi, “mixed matrix membrane application for olive oil wastewater treatment: process optimization based on taguchi design method,” j. environ. manage., vol. 132, pp. 113–120, 2014. 27. h. ashassi-sorkhabi and r. bagheri, “sonoelectrochemical synthesis, optimized by taguchi method, and corrosion behavior of polypyrrole-silicon nitride nanocomposite on st-12 steel,” synth. met., vol. 195, pp. 1–8, 2014. 28. y. g. adewuyi and b. a. oyenekan, “optimization of a sonochemical process using a novel reactor and taguchi statistical experimental design methodology,” ind. eng. chem. res., vol. 46, no. 2, pp. 411–420, 2007. 29. y. w. genichi taguchi, subir chowdhury, taguchi’s quality engineering handbook. 2005. 30. r. k. roy, a primer on thetaguchi method, 2nd editio. society of manufacturing engineers, 2010. 31. b. k. krbaht, b. salih, and a. tanyolac, “electrochemical conversion of phenolic wastewater on carbon electrodes in the presence of nacl,” journal of chemical technology and biotechnology, vol. 77, no. 1. pp. 70–76, 2002. http://www.iasj.net/ iraqi journal of chemical and petroleum engineering vol.14 no.4 (december 2013) 110 issn: 1997-4884 mass transfer enhancement using extensions as turbulence promoters q.j.m. slaiman and buraq s. ahmed chemical engineering department, college of engineering, al-nahrain university abstract mass transfer was studied using a rotating cylinder electrode with different lengths of legs acting as turbulence promoters. two types of rotating cylinder ,made of brass, were examined : an enhanced cylinder one, with four rectangular extensions 10 mm long, 10 mm wide, and 1mm thick, and an enhanced cylinder two with four longitudes 30 mm long,10 mm wide, and 1mm thick. the best performance was obtained for enhanced cylinder two at low rotation speeds while enhanced cylinder one was realized at high rotation speeds. the mass transfer enhancement as compared with a normal rotating cylinder electrode, devoid of promoters, is 53% or 58% higher. the enhancement percentage decreased as rotation speeds increased further, since, seemingly, full turbulence has been reached practically by means of rotation and turbulence promoters. key words: electrochemical reactors, mass transfer, rotating cylinder electrode, limit current, turbulence promoter. introduction the legal limitations for environmental protection require the development of reliable and cost-effective processes for the treatment of effluents with small concentrations of dangerous species. the electrochemical treatment of effluents can be efficiently achieved by the use of rotating cylinder electrode. the advantages of the rotating cylinder electrode (rce) may be summarized in terms of high mass transfer in turbulent flow at low rotation rates, an equipotential surface for potentiostatic control, good solution mixing in a relatively low volume cell, and versatility of design for continuous cascade reactor usage[1-3]. however, in order to further increase the space time yield the incorporation of turbulence promoters has been suggested. therefore; kappesser et al. [4] performed mass-transfer investigations at rotating cylinders with staggered diamond knurls machined on their surfaces. sedahmed et al. [5] studied mass-transfer at rotating finned cylinders. the fins were made by cutting longitudinal rectangular grooves on the cylinder surface. makanjuola and gabe [6] reported mass transfer studies at v-grooved cylinders and the investigation was extended to pyramidal knurling and wires or meshes wound to the cylindrical rotating electrode [7]. further mass-transfer works as a function of the roughness factor are discussed by gabe et al. [8]. nahle´ et iraqi journal of chemical and petroleum engineering university of baghdad college of engineering mass transfer enhancement using extensions as turbulence promoters 2 ijcpe vol.14 no.4 (december 2013) -available online at: www.iasj.net al. [9] studied mass transport to rotating cylinder electrodes fabricated from reticulated vitreous carbon of different porosities. using copper deposition as test reaction they reported that the sherwood number was dependent upon the reynolds number to the power 0.63, both defined in terms of the cylinder diameter. it was also concluded that the mass transfer coefficients are comparable to those at a smooth rotating disk electrode )rde) and rotating cylinder electrode (rce) of the same diameter. thus, enhancements are mainly due to the large electro-active area of the threedimensional matrix. the performance of electrochemical reactors with rotating cylinder electrodes of expanded metal was studied by grau and bisang [10, 11]. it was found that the mass transfer coefficients, using the reduction of ferricyanide, for rotating cylinder electrodes of wovenwire meshes are about three times higher than those obtained with smooth electrodes, because of the turbulence promoting action of the meshes. furthermore, reade, ponce-de-león, and walsh found that the introduction of baffles in the electrochemical cell has little effect on the behavior of a reticulated vitreous carbon rotating cylinder electrode, and a jet electrolyte flow towards the electrode can enhance the mass transfer rate by a factor ranging from 1.03 to 1.46, depending on the electrode type[12]. grau and bisang studied the mass transfer at a rotating cylinder electrode with different turbulence promoters using the reduction of ferricyanide as a test reaction. four types of turbulence promoters were examined: expanded plastic meshes, teflon structures, a plastic woven mesh and a plastic perforated net, which were rotated together with the electrode. they concluded that the best performance was obtained for the teflon structures at low rotation speeds and for the plastic woven mesh at high rotation speeds. the mass-transfer enhancement factor related to a smooth rotating cylinder electrode was found twice as large [13]. the aim of present work is enhancement of mass transfer of dissolved oxygen using turbulent promoters in 0.1n nacl solution at various temperatures under flow conditions and to compare the masstransfer characteristics with rotating cylinder without extensions. experimental work the experimental rig which was used for performing the present work is shown in fig 1. the experimental apparatus was composed of water bath to obtain different solution temperatures, mechanical agitator to obtain different rotational velocities, power supply to apply the current , variable resistance (rheostat) to control the current flow, digital ammeter to measure the current, digital voltmeter to measure the potential, graphite electrode as auxiliary electrode (anode) of an immersed area which was three times larger than the area of cathode (working electrode) to make sure that the limiting current density occurs on cathode. the reference electrode was a saturated calomel electrode (sce) in order to measure the cathode potential using a luggin capillary placed midway of the rotating electrode surface at a distance 1-2 mm from it. the electrical connection of cathode (working electrode) was achieved using brush. the working electrode (cathode) was a rotating cylinder 25 mm in diameter, 27 mm long with four extended rectangular legs 1 and 3 cm long, 1 cm wide , and 1 mm thick, made of brass to generate additional turbulence. the q.j.m. slaiman and buraq s. ahmed -available online at: www.iasj.net ijcpe vol.14 no.4 (december 2013) 3 lower and upper surfaces of the electrode were insulated. the experimental details are shown in figure 2 . before each experimental run, the metal specimen was cleaned by emery paper and washed by tap water followed by distilled water, dried with clean tissue, degreased with annular ethanol, and dried with clean tissue. the specimens were then stored in a desiccator over highly active silica gel for overnight before use, and then directly exposed to the solution for cathodic scanning of limiting current [14].the test solution was 0.1m nacl of ph = 6. when the constant temperature bath attained the required temperature, the working electrode was immersed and the electrical circuit was switched on. the power supply was set at 5 v (applied voltage). the specimen (working electrode) was cathodically polarized from a particular potentials (1.5 to -1.9 v) to the corrosion potential (where iapp. = 0) by changing the applied current using rheostat. the potential was recorded galvanostatically for step changes in current. one minute was allowed for steady state to be reached after each current increment. then the polarization curve can be drawn and the limiting current can be obtained. in a set of experiments the above procedure was repeated for five values of rotation speeds 200,400,600,800, and 1000 rpm at different temperatures (35, 45 and 55 °c). fig. 1, experimental apparatus: 1) power supply,2) resistance box ,3)water bath , 4)0.1m nacl, 5) luggin capillary tip, 6) graphite electrode (anode) ,7) working electrode ,8) rotating shaft ,9)reference saturated calomel electrode (sce), 10) carbon brush ,11) stirrer ,12) stand ,13) voltmeter ,14) ammeter ,15) electrical wires mass transfer enhancement using extensions as turbulence promoters 4 ijcpe vol.14 no.4 (december 2013) -available online at: www.iasj.net (a) enhanced (b) enhanced cylinder 1 cylinder 2 (c) electrolyte flow rate (d) top view of produced by the electrode working electrode rotation fig. 2, schematic view of the working electrode results and discussion the limiting current density il is obtained from polarization curves for smooth rotating cylinder under similar conditions. the limiting current plateau is not well defined, thus the method given by gabe and makanjoula [15] will be adopted to find the limiting current density values as in fig.3 … (1) where i1 and i2 are the currents associated with e1 and e2 respectively. fig. 3, typical polarization curve of dissolved 02 fig.4 shows the cathodic polarization curves in 0.1 m nacl for smooth, enhanced one and two rotating cylinder at 200 rpm for 35, 45, and 55 ᵒc. (a) (b) (c) fig. 4, cathodic polarization curves in 0.1 m nacl for smooth, enhanced one and two rotating cylinder at 200 rpm for (a) 35ᵒc, (b) 45ᵒc, and (c) 55 ᵒc q.j.m. slaiman and buraq s. ahmed -available online at: www.iasj.net ijcpe vol.14 no.4 (december 2013) 5 also, the limiting current density was calculated for smooth cylinder of geometrical characteristics (25mm diameter, 27mm long), enhanced cylinder one, and enhanced two including areas of extensions as listed in table1. table 1, experimental limit current density as a function of velocity at different temperature t e m p e ra tu re rotation rate 𝛚 (rpm) limiting current density, il (ma/cm 2 ) of smooth cylinder limiting current density ,il (ma/cm 2 ) of enhanced cylinder one limiting current density ,il (ma/cm 2 ) of enhanced cylinder two 35 ᵒc 200 0.3134 0.4815 0.49523 400 0.5041 0.70845 0.7243 600 0.61715 0.8068 0.8367 800 0.8956 1.0855 1.138 1000 1.137 1.271 1.286 45 ᵒc 200 0.3543 0.53175 0.56535 400 0.5443 0.7454 0.7543 600 0.7194 0.894 0.9223 800 1.0012 1.14715 1.1455 1000 1.236 1.3645 1.3515 55 ᵒc 200 0.371 0.54765 0.566 400 0.66855 0.8509 0.8656 600 0.80865 0.9586 0.96835 800 1.146 1.308 1.302 1000 1.3965 1.5325 1.469 the mass transfer coefficient, k is calculated from the following equation, k = il/nefcb …(2) where ne =charge number of the electrode reaction, f= faradays constant (96487 columb/equivalent), and cb = bulk concentration(mole/m 3 ) , for system under mass transfer control cb =co2 which is the concentration of o2 in the solution bulk. table 2, shows the oxygen solubility and concentration for different temperatures [19] t (ᵒc) solubility (mg/l) 0.1nacl cb (mole/m 3 ) 35 5.9445 0.21718 45 4.894 0.18718 55 4.9445 0.154515 figure 5 shows the mass transfer coefficient, k, as a function of reynolds number for enhanced one, and enhanced two rotating cylinder electrodes at different temperatures. the experimental mass-transfer coefficients for a similar smooth rotating cylinder electrode are also reported in this figure, which provides a baseline for performance comparison. it can be seen that as reynolds number increases k is increased. this can be attributed to the increase in oxygen supply from the bulk of the solution to the metal surface leading to higher il [16] according to equation (2), thus k will be increased. this is because of leg extensions, which present a higher specific area and promote additional turbulence in the electrolyte flowing over the cylinder surface. the k values for enhanced one and two cylinders are higher than dictated by the additional cylinder area only as displayed in fig.5. figure 6 shows the mass transfer coefficient, k, as a function of the temperature for smooth, enhanced one, and two rotating cylinder electrodes at different re numbers. it is clear that as the temperature increases k increases. this is due to the fact that increasing temperature accelerates the reaction rate as dictated by arrhenius equation. likewise, increasing temperature will increase the rate of oxygen diffusion to the metal surface and decrease the viscosity of water which will aid the oxygen diffusion. moreover, as the temperature increases, the oxygen solubility decreases. the k values are still higher showing that the diffusion has a higher degree of effect than o2 solubility [18]. in order to determine the efficiency of enhancement due to extensions a percentage (ep) can be defined as: …(3) mass transfer enhancement using extensions as turbulence promoters 6 ijcpe vol.14 no.4 (december 2013) -available online at: www.iasj.net fig. 5, mass transfer coefficient k vs. re for the three temperatures (a) 35ᵒc (b) 45ᵒc (c) 55ᵒc q.j.m. slaiman and buraq s. ahmed -available online at: www.iasj.net ijcpe vol.14 no.4 (december 2013) 7 fig. 6, mass transfer coefficient vs. re (a) smooth cylinder, (b) enhanced cylinder1, and (c) enhanced cylinder 2 mass transfer enhancement using extensions as turbulence promoters 8 ijcpe vol.14 no.4 (december 2013) -available online at: www.iasj.net fig.7 shows the enhancement percentage as function of the re number for enhanced cylinder one, and two in terms of temperature. the enhancement percentage ranges from 58% to 5% depending mainly on rotation speed; the greater re the smaller is the enhancement percentage for a given temperature. this may be attributed to the fact that the effect of extensions which act as turbulence promoters is practically limited, since full turbulence had already been achieved by means of rotation, i.e, re. also, fig.7 compares enhancement percentages for enhanced cylinder one and two. as shown for the lower re values enhanced cylinder two is more efficient than one. this indicates that the transition to turbulence occurs earlier due to promoters. however, the reverse, is, apparently indicated at higher re. moreover, it is to be noticed from fig.7 that at high temperature the percentage of enhancement is lower. this can be explain as the temperature increase the mass transfer coefficient increase for smooth and enhanced cylinder electrode and the effect of extensions which acting as turbulent promoter will be diminish this lead to the values of k approximately close to each other and enhancement percentage reduce. although, the effect of extensions length on the enhancement factor can be considered as few. fig. 7, comparison of mass transfer enhancement using rotating cylinder electrodes with extensions conclusions 1. mass transfer coefficients for enhanced rotating cylinder electrode are, in general, about 53% or 58% higher those obtained with smooth electrode without extensions. 2. the mass transfer enhancements are due in the main to leg extensions, which present a higher specific area and promote additional turbulence in the electrolyte flowing over the cylinder surface. 3. the enhancement percentage decreases as re increased by the average 47.26%. this may be attributed to the fact that the effect of extensions which act as turbulence promoters is practically limited, since full turbulence had already been achieved by means of rotation, i.e, re. q.j.m. slaiman and buraq s. ahmed -available online at: www.iasj.net ijcpe vol.14 no.4 (december 2013) 9 4. the enhancement percentage decreases as the temperature increased the average 33.727%. this can be explain as the temperature increase the mass transfer coefficient increase for smooth and enhancement cylinder electrode and the effect of extensions which acting as turbulent promoter will be diminish this lead to the values of k approximately close to each other and enhancement percentage reduce. references 1d.r. gabe, (1974),” the rotating cylinder electrode”, j.appl.electrochemistry, no.2, vol.4, pp. 91. 2d.r. gabe and f. c. walsh, (1983),” the rotating cylinder electrode: a review of development”, j. appl. electrochemistry, no.1, vol.13, pp. 3. 3ralph e. white, (1984),” electrochemicalcell design”, springer-verlag us, pp. 225-258. 4r. kappesser, i. cornet and r. greif, (1971),” mass transport to a rough rotating cylinder”, j. electrochemistry. soc., no.10, vol. 118, pp. 1957. 5g.h. sedahmed, a. abdel khalik, a.m. abdallah and m.m. farahat, (1979),” mass transfer at rotating finned cylinders”, j. appl. electrochem., no.5, vol.9, pp. 563. 6p.a. makanjuola and d.r. gabe, (1985),” a study of roughness and mass transfer enhancement for the rotating cylinder electrode”, surf. technol., no.1, vol. 24, pp. 29. 7p.a. makanjuola and d.r. gabe, (1987),” enhanced mass transfer using roughened rotating cylinder electrodes in turbulent flow”,j.appl.electrochemistry, no.2,vol.17, pp. 370. 8d.r. gabe, g.d. wilcox, j. gonzalez-garcia and f.c. walsh, (1998),” the rotating cylinder electrode: its continued development and application”,j. appl. electrochem.,no.8,vol. 28 ,pp.759. 9a.h. nahle´, g.w. reade and f.c. walsh, (1995),” mass transport to reticulated vitreous carbon rotating cylinder electrodes”, j. appl. electrochem., no.5, vol. 25, pp.450. 10j.m. grau and j.m. bisang, (2005),” mass transfer studies at rotating cylinder electrodes of expanded metal”, j. appl. electrochem. , no.3, vol.35, pp. 285. 11j.m. grau and j.m. bisang, (2006),” mass transfer studies at packed bed rotating cylinder electrodes of woven-wire meshes”, j. appl. electrochem. ,, no.7, vol.36, pp.759. 12g.w. reade, c. ponce-de-león, f.c. walsh, (2006),” enhanced mass transport to a reticulated vitreous carbon rotating cylinder electrode using jet flow”, electrochim. acta, no.13, vol, 51, pp. 2728–2736. 13j.m. grau, j.m. bisang, (2011),” mass-transfer studies at rotating cylinder electrodes with turbulence promoters”, chemical engineering and processing, no.9, vol.50, pp. 940– 943. 14koichi asano,(2006), "mass transfer from fundamentals to modern industrialapplications", wiley-vch verlag gmbh and co. kgaa, pp. 325 15d.r. gabe and p.a. makanjoula, (1986), efcf publication series no. 15, electrochemical eng., aiche symposium series, no. 98, p.309, 1986. 16mahato, b. k., c. y. cha, and w. shemilt. corros. sci., (1980),” mass transfer enhancement using extensions as turbulence promoters 10 ijcpe vol.14 no.4 (december 2013) -available online at: www.iasj.net unsteady state mass transfer coefficients controlling steel pipe corrosion under isothermal flow conditions”, no.3, vol. 20, p. 421. 17welty j. r., c. e. wicks, and g. rorrer, (2001),"fundamental of momentum, heat and mass transfer, 4th edition, john wiley and sons, united state of america, pp.205. 18uhlig h. h.,"corrosion and corrosion control",(1985), 3rd edition, wiley-interscience publication, new yourk, . pp. 100 19sense f., (2001), “oxygen solubility”, north california state. iraqi journal of chemical and petroleum engineering vol.16 no.1 (march 2015) 3548 issn: 1997-4884 reduction of sulfur compounds from petroleum fraction using oxidation-adsorption technique nada sadoon.ahmedzeki, ban jaber ibrahem chem.eng.dept.college of eng., university of baghdad, iraq. abstract oxidation of sulfur compounds in fuel followed by an adsorption process were studied using two modes of operation, batch mode and continuous mode (fixed bed). in batch experiment oxidation process of kerosene with sulfur content 2360 ppm was achieved to study the effect of amount of hydrogen peroxide(2.5, 4, 6 and 10) ml at different temperature(40, 60 and 70)°c. also the effect of amount acetic acid was studied at the optimal conditions of the oxidation step(4ml h2o2 and 60 °c).besides, the role of acetic acid different temperatures(40, 60, 70) °c and 4ml h2o2, effect of reaction time(5, 30, 60, 120, 300) minutes at temperatures(40,60) °c, 4ml h2o2 and 1 mlhac) and effect of reaction temperature were studied. the results showed that the percentage removal of sulfur compounds increases with the increasing amount of hydrogen peroxide and amount of acetic acid also the percentage removal of sulfur compounds increases by addition acetic acid, reaction time up to 300 minutes and reaction temperature. in the fixed bed adsorption process, the oxidized kerosene having sulfur content being reduced to 939.28 ppm, was let to flow through a bed of 10ni/𝛾-al2o3. the results showed that a sulfur removal of 95.38 % was obtained. by this the total sulfur removal of 98.38 % was obtained from the two consecutive processes. the resultant fuel had only 43.47 ppm. also a study of the capability of the same bed to desulfurize raw feed of kerosene of 2360 ppm of sulfur compounds was investigated. 43.3% removal of sulfur compounds was achieved which reflects the catalytic properties of the adsorbent which could act as an oxidative adsorptive material. the results showed that by increasing feed flow rate, the breakthrough curve becomes steeper. also the maximum removal of sulfur compounds was obtained in the case of bed height 20 cm and flow rate 0.3 l/h. key words: oxidation-adsorption, petroleum fraction, sulfur compounds introduction the use of fossil fuels in various sectors for heat and power generation continues to loom up global stability and sustainability, more over sulfur containing compounds present in gasoline and diesel are making extra undesirable effectdue to the emission of toxic gases[1]. in order to protect the human health and reduce the environmental hazards, environmental regulation that tend to limit the sulfur levels to very low levels, have already been introduced in many countries iraqi journal of chemical and petroleum engineering university of baghdad college of engineering reduction of sulfur compounds from petroleum fraction using oxidation-adsorption technique 36 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net during the last few decades. also sulfur should be removed from the petroleum fractions as it causes poisoning of catalysts, corrosion of surfaces, and air pollution [2,3]. nowadays, hydrodesulfurization (hds) is the main method for the removal of sulfur from petroleum distillates in a refinery. although hds can eliminate aliphatic and cycle sulfur containing compounds effectively, it needs high temperature and high hydrogen pressure, which leads to many problems such as high investment, high operating cost and reduction of the catalyst cycle length. besides, it is difficult for hds to remove thiopheniccompounds such as dibenzothiophene (dbt) and its derivatives due to their steric hindrance. therefore, the development of the alternative desulfurization processes like adsorption, oxidation, extraction and biodesulfurization is necessary [4]. among these methods, oxidative desulfurization (ods) has been demonstrated to be a promising method for ultradeep desulfurization technology because of its mild operation conditions, no hydrogen required and low cost of operation. during the process, the organosulfur compounds are oxidized to their corresponding sulfoxides or sulfones. the process is carried out in the presence of a catalyst and an oxidant agent, and the oxidized sulfur compounds are subsequently removed by extraction, adsorption, distillation, or decomposition [5,6]. potential oxidative routes to produce ultralow sulfur fuels include the use of various oxidizing agent such as nitric acid, nitrogen oxides, organic hydroperoxides and peroxide. the most promising oxidation systems in the terms of selectivity, product quality, safety, environmental impact and cost of effectiveness are those using hydrogen peroxide as oxidizing agent [7]. fig.(1) shows simplified network for ods of dbt(8). fig. 1, simplified network for ods of dbt. adsorption is one of the most promising processes for deep desulfurization of fuel. this process is effective in the selective removal of low concentration materials from liquids. the fuel is brought in contact with a solid adsorbent which selectivity adsorbs sulfur containing compounds [9]. desulfurization by adsorption depends on the ability of a solid sorbent to selectively adsorb organosulfur compounds from oil [10] on the other hand, adsorptive desulfurization is a new challenge to remove sulfur compounds from the transportation fuels, because adsorption would be accomplished relatively at lower temperature and pressure. chen et al 2010[11] utilized an uoad(ultrasound-assisted oxidative desulfurization) for a diesel fuel of, and the study revealed in a 89% reduction producing a fuel containing 800ppm sulfur compounds. most of the previous studies dealt with model fuels rather than real ones with low sulfur content of less than 1000 ppm (12). the main objective of this work is to study the oxidative desulfurization as applied to iraqi kerosene with 2360 ppm sulfur content, followed by the study of the ability of nickel loaded on –alumina nada sadoon.ahmedzeki, ban jaber ibrahem -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 37 for a further sulfur removal. this study was designed as follows: batch mode oxidation using hydrogen peroxide. the effects of the amount of h2o2,amount of acetic acid, temperature, addition of acetic acid, and reaction time were studied. 10% ni/𝛾-alumina was prepared by impregnation method and used for treating the oxidized kerosene from the batch step. the effect of flow rate, bed height, and adsorbent loading was studied, also desulfurization of raw kerosene using a bed of ni/𝛾 al2o3 was studied. experimental materials kerosene, boiling point 156.2237.3⁰c with sulfur content 2360 ppm, density 0.78 g/cm3,was supplied by the al-dora refinery, γ-alumina (spheres,3mm)supplied by procatalyse, france. hydrogen peroxide(50%) from schralau. acetic acid(99.5%), rediel, and n2nio6.6h2o(99.7%), fisher certified. procedure oxidation experiments (batch mode) in each experimental run, 100 ml of untreated kerosene was introduced into a three – necked round bottom flask reactor equipped with fractionating column, condenser fig(3), was stirred continuously at constant mixing speed(500 rpm) and heated to the desired reaction temperature using the magnetic stirrer heater. when the mixture reached the selected reaction temperature, the specified amount of hydrogen peroxide was aed to the reaction mixture. the reaction time was set to be 300 minutes. then, the solution was allowed to settle in a 100 ml separating funnel where clear distinguishable phases were obtained. after that sample was withdrawn. figure (2) shows the two phase separation. in order to study the effect of acetic acid, the specified amount of the acid was added to the reaction mixture after the addition of hydrogen peroxide immediately. this procedure was followed as in ahmedzeki and ban 2014[12]. fig. 2, two phase separation fig. 3, oxidation setup adsorbent preparation nickel loaded on gamma alumina was prepared by the impregnation method. trials were made to obtain the desired loading percent. it was reduction of sulfur compounds from petroleum fraction using oxidation-adsorption technique 38 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net intended to prepare 10wt% ni [13]. for this, 50g of 𝛾-al2o3 was soaked in 60wt% ni(no3)2.6h2o aqueous solution in 600 ml beaker. the mixture was stirred in a jar test apparatus for 48 hrs. the next steps were, filtration using buckner funnel with a vacuum pump, overnight drying in an oven at 110 °c and finally calcination in a programmable electrical furnace at 550°c for 5 hrs. characterization of the adsorbent was made using xrd, , surface area, and atomic absorption adsorption experiments (continuous mode) the complementary desulfurization step was carried out in a continuous mode laboratory rig (fig 4). it consisted of qvf adsorption column 2.54 cm diameter and length of 35 cm. a gauze plate of fine mesh was placed in the bottom of column to hold the spheres of the adsorbent. kerosene from the previous step (with the best conditions) was fed to the column in a down flow manner. flow rate of the entering feed was measured by a rotameter and was distributed by two layers one of ceramic balls and the other of glass beads. the flow rate and bed height were adjusted at the desired value for each run. samples of the effluent from the adsorption column were analyzed for sulfur content at different time intervals. this test was made in the al-dora refinery by sulfur content analyzer (antek). extra runs were carried out on a fresh feed to investigate the capability of ni/𝛾al2o3 to reduce sulfur content without the oxidation step using hydrogen peroxide. fig. 4, continuous adsorption unit results and discussion oxidation experiments effect of amount of hydrogen peroxide different amounts of h2o2 (2.5, 4, 6, and 10) ml was added to 100 ml of kerosene at differenttemperature (40, 60, and 70)°c at constant stirrer speed of 500 rpm and constant time of 300min.. as shown in figure (5), the removal efficiency of sulfur compounds was found to increase with increasing amount of h2o2 to a certain point. this can be explained that the larger excess of hydrogen peroxide, on the one hand can be attributed to the thermal decomposition during the reaction attributed to the function of the oxidant in converting sulfur compound to sulfoxides and/ or sulfones. on the other hand excess amount is present the thermal decomposition during the reaction would cause a dilution and increase nada sadoon.ahmedzeki, ban jaber ibrahem -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 39 of the aqueous phase by which a decrease in the removal efficiency will occur[14].another reason is the different types of sulfur compound like sulfides, thiophenes and their derivatives which differ in their reactivity keeping them unconcerned with higher amount of the oxidant. therefore, from an economic point of view, and reaction rate into consideration, 4 ml h2o2 was chosen for further investigation, these results are well agreed with li et al.,2013[14].it was noticed that at 70 °c and using 10 ml of h2o2 an increase in the sulfur removal was obtained. so, it can be concluded that increasing the amount of h2o2 along with increasing temperature had more pronounced effect resulting a more sulfur removal to about 65%. fig. 5, the effect of amount of h2o2 on sulfur removal at different temperatures,500 rpm,300min. effect of reaction temperature the effect of reaction temperature on sulfur removal efficiency was investigated for reaction time of 300 minutes at 40°c, 60°c and 70°c using different amount of hydrogen peroxide; (2.5, 4, 6 and 10) ml as shown in figure (6). the results obtained indicated an enhancement the oxidation of thiophene compounds and it derivatives to sulfoxide and sulfones on increasing reaction temperature from 40°c to 70°c improvement in sulfur removal efficiency. as clear at 40 °c the sulfur removal was lower than those 60 °c and 70°c. the increase in reaction temperature enhances the oxidation of kerosene. this may be related to the decomposition of hydrogen peroxide paralleled with increase in reaction temperature to produce hydroxyl radicals that act as strong oxidizing agent. therefore, 60°c as chosen as the reaction temperature and the higher temperature had no further beneficial effect on sulfur removal. the same behavior was also, observed by many investigators, like lanju et al., 2006[15], who studied oxidation of thiophenes by using silica gel in hydrogen peroxide and formic acid system, and found that the sulfur removal rates are improved with the temperature exceeds 50°c while peng et al., 2007[16] reported that the best results occurred at 70°c because increasing temperature contributed to the acceleration in the reaction speed; cui et al., 2007[17]; zhang et al., 2012[18] and yu and wang.,2013[19] found the oxidation reaction run efficiently under 60 °c . fig. 6, the effect of reaction temperature on sulfur removal at different amount of h2o2 at 300min effect of amount of acetic acid the effect of amount of acetic acid on sulfur removal efficiency at temperature 60°c and 4 ml hydrogen 0 10 20 30 40 50 60 70 0 5 10 15 % s u lf u r r e m o l amount of h2o2(ml) 40⁰c 60°c 70°c 0 50 100 40 60 70% s u lf u r r e m o v a l temp(ᵒc) 2.5 ml 4 ml 6 ml 10 ml reduction of sulfur compounds from petroleum fraction using oxidation-adsorption technique 40 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net peroxide was studied for the purpose of determining the best amount that will bring a best removal. the results of the dependence acetic acid catalyst oxidant are shown in figure (7). this figure represents the plotting of the amount of acetic acid with sulfur removal. the sulfur removal increase with increasing amount of acetic acid. this figure can clearly show that the increase in the sulfur removal is due to peracetic acid forming by acetic acid and hydrogen peroxide.therefore the oxidation reaction can be promoted by increasing acetic acid concentration. besides the oxidation rate increases with decreasing ph for example at 6 ml of acetic acid (ph 1.83) sulfur removal was 70% while at 8 ml acetic acid (ph 1.63) sulfur removal increased to 74.19%. the above results agreed with those obtained by yu et al., 2005[20] and dehkordi et al., 2009[21]. fig. 7, the effect of amount of acetic acid on sulfur removal, at 60°c and 4 ml h2o2 the role of acetic acid in oxidation desulfurization in order to evaluate the improvement obtained by addition acetic acid on removal of organosulfur compounds, applying different temperature (40, 60, and 70)°c, for a constant amount of hydrogen peroxide 4 ml and 1 ml acetic acid was investigated, as shown in fig. (8) . fig. 8, the effect of addition acetic acid 4 ml h2o2, 1 ml hac it is obvious that the addition of acetic acid is improving the sulfur removal efficiency. at constant time of 300 minutes and without using acetic acid the sulfur removal obtained was 59.7% at 70ºc but it was 61% with acetic acid at the same temperature. this is explained that the sulfur removal increase by addition acetic acid because acetic acid catalyzes the oxidation reaction of sulfur containing compounds via forming peracetic acetic, which acts as an oxidizing agent giving its oxygen atom to the sulfurcontaining compounds present in kerosene. peracetic acid is formed in situ by acetic acid and hydrogen peroxide, therefor, the oxidation reaction can be promoted by addition acetic aciddehkordi et. al.,2009[21]. it is known that acids cause polarization of the o–o bond in hydrogen peroxide and accelerate the reaction both in the heteroand homolytic direction due toa decrease in the activation energy of the transitional state. however, crude-cut sulfides can be oxidized into sulfoxides while heating without acids. in this case, initially molecules of hydrogen y = 2.0929x + 57.306 r² = 0.9916 50 55 60 65 70 75 80 1 2 3 4 5 6 7 8 9 10 % s u lf u r r e m o v a l amount of hac(ml) 54 55 56 57 58 59 60 61 62 20 30 40 50 60 70 80 % s tu fu r r e m o v a l temp(°c) with hac without hac nada sadoon.ahmedzeki, ban jaber ibrahem -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 41 peroxide and then the acids formed participate in polarization of hydrogen peroxide. the degree of polarity is lower in the first case than in the second case. this is indicated by the low oxidation rate of sulfides in the absence of acids [22]. effect of reaction time fig. (9) shows sulfur removal as a function of reaction time at operating temperature 40°c and 60ºc, amount of h2o2 4 ml and 1 ml acetic acid. the results were improved by increasing time of the reaction. this could be explained by describing interaction of oxidizing agents as time proceeds h2o2 and acetic acid can interact with dibenzothiophene to produce sulfones. this reaction like any other reaction needs enough time to complete and promotes as time goes on. best results were observed at 300 minutes [23]. a similar behavior was obtained byyanxiuet al., 2013[24] foroxidative desulfurization of model sulfur compound by potassium ferrate presence of phosphomolybdic acid catalyst who found that the residual sulfur content decreased with an increasing oxidation time. the reaction was close to equilibrium and the residualsulfur content almost did not change. fig. 9, the effect of reaction time on sulfur removal, amount of h2o2= 4 ml, amount of hac= 1 ml, temp=40°c and 60°c adsorbent characterization x-ray diffraction (xrd) x-ray diffraction is one of the oldest and most frequently applied techniques in catalyst characterization. it is used to identify crystalline phase inside catalysts by means of lattice structural parameters, and to obtain an indication of particle size[25].xrd analysis was carried out to identify the phase transformation of al2o3 support. by comparing with standard xrd pattern it is concluded that alumina was of gamma phase.the comparison of lattice spacing between alumina and standard xrd is shown in table(1). the results showed that the gamma alumina was very near to the standard. table (1), comparison of lattice spacing between alumina and standard xrd standard xrd alumina d, spacing angle(2theta) deg. angle(2 -theta) deg. 4.56 19.450 4.54528 19.5143 2.8 31.936 2.86963 31.1419 2.39 37.603 2.42115 37.1027 2.28 39.491 2.29765 39.1761 1.977 45.862 1.97808 45.8365 1.520 60.897 1.54236 59.9244 nickel content and its effect on surface area, pore and porosity the surface area, pore volume and porosity of 𝛾-al2o3 and ni/𝛾-al2o3 is shown in table (2). as observed in table (2) surface area and pore volume of the sorbent decreased with loading ni on 𝛾-al2o3 by blocking the active sites. on increasing the nickel content loading total specific surface area of the 0 10 20 30 40 50 60 70 0 200 400 % s u lf u r r e m o v a l time(min) 40 ⁰c 60⁰c reduction of sulfur compounds from petroleum fraction using oxidation-adsorption technique 42 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net adsorbent decreased from 203.6 m 2 /g (for 𝛾-al2o3) to 174.5391 m 2 /g (for ni/𝛾-al2o3). table (2), adsorbent characterization porosity (%) pore volume (cm 3 /g) surface area (m 2 /g) 83.7040 0.561 203.6 𝛾-al2o3 80.6325 0.458 174.5391 ni/𝛾al2o3 the pore volume of sorbent also decreased accordingly as the loading of the metal increased on the support. this is due to the ni impregnation on the microstructure. these nickel particals are responsible for the adsorption of refractory sulfur compounds. thus nickel the development of larger ni particals at higher concentration ( 10% ) reduces the active sites per unit mass due to the agglomeration and growth of ni crystal. which filled the pores of the support covering its surface. the desulfurization process strongly depends on the properties of the metal as well as the support materials. adsorption of sulfur compounds onto 𝛾-al2o3 is a complex process and mainly controlled by both chemical interaction and physical factors. ni metal sites helps in the removal of the organosulfur compounds having heteroatoms while the acidic parts of support helps in the removal of the substituted sulfur compounds having alkyl hindrance, reported that ni has a reactive tendency and has been effective metal for removal of refractory sulfur compounds which have no alkyl hindrance. the sulfur removal increased up to 8-10% metal loading and decreasing thereafter. this can be explained by the fact that ni has strong molecular orbital that can attract the hindered benzothiophene and other cyclic sulfur compounds which can donate the electron density to the metal and further can make the metal more effective. this is results agreed withsarda et al., 2012[12]. effect of operating conditions effect of flow rate the effect of varying the volumetric flow rate (0.3 and 0.6) l/hr on the adsorption sulfur compounds from kerosene is shown by breakthrough curves drawn in figures(10,11) in term of c/cₒ ver u t me .the d orbe t bed height was fixed at 10 cm or 20 cm and inlet concentration of oxidized kerosene (939.28 mg/l) from the previous oxidation step. increasing the flow rate may be expected to make reduction on the thickness of the surface film. therefore, this will decrease the resistance to mass transfer and increase the mass transfer rate due to easy passage of the adsorbent molecules through the particles and entering easily to the pores, in contrast this will decrease the contact time required between at a high flowrate to reach the desired concentration. as flow rate increased, the breakthrough curves become steeper and reached the breakthrough quickly. this means that the contact time between kerosene and ni/γ-al2o3 is minimized, loading to early breakthrough. increasing the flow rate gave to a shorter time for saturation due to adsorbate concentration, therefore the sulfur compounds do not have sufficient time to diffuse into pores of the adsorbent hence, sulfur removal increases with decreasing flow rate as shown in figures (12, 13). these results agree with that obtained by zeinab, 2012[26] and hamsa, 2013[27]. nada sadoon.ahmedzeki, ban jaber ibrahem -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 43 fig. 10, breakthrough curves for adsorption sulfur compounds at different flow rate, h=20 cm) fig. 11, breakthrough curves for adsorption sulfur compounds at different flow rates,h=10 cm fig. 12, sulfur removal efficiency at different flow rates, h=20 cm fig. 13,sulfur removal efficiency at different flow rates, h=10 cm effect of bed height the effect of bed height was investigated for sulfur compounds adsorption onto ni/𝛾-al2o3; the experimental breakthrough curves are presented in fig. (14, 15). the breakthrough curves were obtained for two bed heights (10 and 20) cm which represented a weight of (43.8 and 87.6) grams respectively. this was studied for two flow rates( 0.3 or 0.6) l/hr. it is clear that the increase in bed height increases the breakthrough time also, means an increase in the mass of the adsorbent packed in the column which offers more available adsorption sites for an adsorbate to be adsorbed. this shows that at smaller bed height the effluent adsorbate concentration ratio increased more rapidly than for a higher bed. furthermore, the bed is saturated in less time for smaller bed height. therefore, removal efficiency increases with increasing bed height, increasing the sorbent mass increased the corresponding sorption sites and sulfur species get enough time to diffuse into pores of the adsorbent as shown in figures(16,17). this behavior was in agreement withmohammd, 2004[28] and hamsa, 2013[27]. 0 0.2 0.4 0.6 0.8 1 0 50 100 150 200 250 300 350 c /c ₀ time(min) 0.3 lit/hr 0.6 lit/hr 0 0.2 0.4 0.6 0.8 1 0 100 200 c /c ₀ time(min) 0.3 lt/hr 0.6 lit/hr 0 10 20 30 40 50 60 70 80 90 100 0 200 400 % s u lf u r r e m o v a l time(min) 0.3 l/hr 0.6 l/hr 0 20 40 60 80 100 0 50 100 150 200 % s u lf u r r e m o v a l time(min) 0.3 l/hr 0.6 l/hr reduction of sulfur compounds from petroleum fraction using oxidation-adsorption technique 44 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net fig. 14, breakthrough curves for the adsorption sulfur compounds at different bed height, q=0.3 l/hr fig. 15, breakthrough curves for adsorption sulfur compounds at different bed height, q=0.6l/hr fig. 16, sulfur removal efficiency at different bed height, q=0.3 l/hr fig. 17, sulfur removal efficiency at different bed height, q=0.6 l/hr from these results, it is clear that the maximum removal of sulfur compounds was obtained at the bed height 20 cm with flow rate 0.3 l/hr. shown in figure (12), 95.38% of the sulfur compounds was removed at the first five minutes. also, it can be seen that after 30 minutes, 73.6% removal was obtained which is good enough to get rid of this amount of the harmful sulfur compounds, so regeneration of the bed at this time is recommended. at this time the bed adsorption capacity was calculated using equation(1), where it was found equals to 1.182 mg sulfur/g ni/𝛾-al2o3[29]. ∫ ( ( …. (1) q: adsorption capacity(mg sulfur/g ads) : feed volumetric flow rate(ml/minute) : weight of adsorbent(g). : initial concentration (mg/l). ( : concentration at any time (mg/l). t: time(minute). breakthrough curves with h2o2 and without h2o2 fig. (18), shows breakthrough curves for adsorption of sulfur compounds in 0 0.2 0.4 0.6 0.8 1 0 50 100 150 200 250 300 350 c /c ₀ time(min) 10 cm 20 cm 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 100 200 c /c ₀ time(min) 10 cm 20 cm 0 20 40 60 80 100 0 50 100150200250300350400 % s u lf u r r e m o v a l time(min) 10 cm 20 cm 0 10 20 30 40 50 60 70 80 90 100 0 50 100 150 200 % s u lf u r r e m o v a l time(min) 10 cm 20 cm nada sadoon.ahmedzeki, ban jaber ibrahem -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 45 kerosene with h2o2 and without h2o2 while figure(19) shows sulfur removal efficiency as a function of time. these figures shows sulfur removal increased from 43.3% without h2o2 to 95.38% in the presence of h2o2. this is due to the fact that h2o2 oxidized benzothiophe and its derivatives to sulfoxide and then to corresponding sulfones which can be easily adsorbed on ni/𝛾-al2o3. thus a combination of oxidant and adsorbent is effective because ni has strong molecular orbital that can attract the hindered sulfur compounds and h2o2 can remove the linear and cyclic sulfur compounds by converting them to sulfones which can be adsorbed easily [12]. while adsorption process of kerosene without h2o2 can be explained that thiophene has two lone pair of electrons on the sulfur atoms: one pair lies on the six –electron pi system and their lies in the plane of the ring thiophene can act either as an type donor by donating the lone pairs of electrons that lie in the plane of the ring to the adsorbent or as a pi type donor by utilizing the delocalized pi electron of the aromatic ring (pi bond) to form a pi type complex with the metal ions. on the other hand, the sulfur adsorption capacity and selectivity of adsorbent can be further improved by modifying various types of surface active sites for sulfur adsorption, such as lewis sites, useful functional groups, electronic defect centers, micro-structural defects and so on. according to lewis acid-base theory, most thiophene sulfur compounds in jet fuels are lewis base, which are easy to be adsorbed at lewis acid sites. hence, materials can be design and select that process strong lewis acid sites to selectivity adsorb thiophene sulfur compounds with lone pair in jet fuels. the lewis acid-base adsorption mechanism is interaction between the acid sites on the surface of adsorbent and thiophene derivatives. additionally, it is known that the sulfur compounds have more affinity to oxidation than their analog hydrocarbon in jet fuels; therefore, perfect redox properties of adsorbent can improve oxidation of sulfur compounds into sulfones and sulfoxides. high conversions of sulfides to sulfones and sulfoxides provide stronger polarities that enhanced selective removal of organic sulfur compounds with solid adsorbent at ambient temperature and atmospheric pressure. as a consequence, perfect redox properties of adsorbent can indirectly increase the sulfur adsorption capacity and selectivity [30]. fig. 18, experimental breakthrough curves for adsorption sulfur compounds q= 0.3 l/hr, h=20 cm) fig. 19, sulfur removal efficiency with h2o2 and without h2o2, q=0.3 l/hr, h=20 cm 0 0.2 0.4 0.6 0.8 1 0 50 100 150 200 250 300 350 c /c ₀ time(min) with h2o2 without h2o2 0 20 40 60 80 100 0 200 400 % s u lf u r r e m o v a l time(min) with h2o2 without h2o2 reduction of sulfur compounds from petroleum fraction using oxidation-adsorption technique 46 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net conclusions the present study led to the following conclusions: 1the oxidation of sulfur compounds from kerosene by hydrogen peroxide with acetic acid shows better performance as compared to oxidation without acetic acid. the sulfur removal efficiency of both conditions is 60.2% and 58% respectively.2-sulfur removal efficiency by oxidation process increases with increasing reaction temperature, amount of hydrogen peroxide and reaction time. the preferable operating conditions are 60º c, 4 ml h2o2and 300 minute. 2acetic acid was found to act as a catalyst for the oxidation process. it was found that by adding 1ml acetic acid at 4 ml h2o2 and reaction temperature 60 °c the removal efficiency was enhanced to 60.2%. 3the fixed bed adsorption process may be considered as a complementary desulfurization process. it was found that the sulfur removal increases with increasing bed height and decreasing flow rate. 4the highest sulfur removal efficiency is 95.38%, obtained by treating oxidized kerosene in the presence h2o2 by ni/𝛾-al2o3 at fixed bed experiment in adsorption process at 20 cm bed height with 0.3 l/hr flow rate to obtain ultrafine fuel. 5maximum sulfur removal efficiency of kerosene without h2o2 oxidization step in the ni/𝛾al2o3 fixed bed is 43.3%. references 1. battaglini, a., lilliestam, j., haas, a., patt, a., 2009. development of super smart grids for a more efficient utilisation of electricity from renewable sources. j. cleaner prod. 17, 911-918. 2. zhu, w., zhu, g., li, h., chao, y., chang, y., chen, g., and han, c., 2011 "oxidative desulfurization of fuel catalyzed by metal-based type ionic liquids",molecularcatalysisa:che mical 347:8-14. 3. vardhaman, a. k., sikdar, s., and sastri, c.v., 2011,"oxidation of desulfurization by mononuclear non-heme iron compleexes: abiomimetic approach for oxidative desulfurization", indian journal of chemistry, 50 a: 427431. 4. junbo, l., xiwen, l., cancan, c., jia, g., and zhiquan, p., 2013, "silica-gel supported v complexes: preparation, characterization and catalytic oxidative desulfurization", chinese journal of chemical engineering, 21(8): 860-866. 5. garcia, e. t., galano, a., and rodriguez, g., 2011, "oxidative desulfurization (ods) of organosulfur compounds catalyzed by peroxo-metallate complexes of wox-zro2: themochemical, structural, and reactivity indexes analysis", journal of catalysis, 282: 201-208. 6. lei, w., shuzhen, l., haijun, c., yanyan, x., xihui, w., and yujing, c., 2012, "ultra-deep desulfurization of fuel with metal complex of chitosan schiff base assisted by ultraviolet", fuel,94:165-169. 7. filippis, p. d., and scarsella, m., 2003, "oxidative desulfurization: oxidation reactivity of sulfur compounds in different organic matrixes", energy & fuels, 17:1452-1455. 8. zhao, d., wang, y., and duan, e.,2009, "oxidative desulfurization nada sadoon.ahmedzeki, ban jaber ibrahem -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 47 of fuel oil by pyridinium-based ionic liquids", molecules,14:4351-4357. 9. music, m., gomzi, z., biondasertic, k, 2009, "analysis of continuous fixed bed adsorptive desulfurization of diesel fuel", faculty of chemical engineering and technology, marulicevtrg 19, 10000 zagreb croatia. 10. javadli, r., and de klerk, a., 2012" desulfurization of heavy oil",appl petroleum res. 11. chen, teng-chien ,shen, yunhwei, lee, wen-jhy , lin, chihchung, wan meng-wei, 2010, the study of ultrasound-assisted oxidative desulfurization process applied to the utilization of pyrolysis oil from waste tires, journal of cleaner production 18, 1850e1858. 12. ahmedzeki nada s. and ban jaberibrahem2014., “reduction of sulfur compounds from petroleum fraction using oxidationadsorption technique” msc. thesis, chemical engineering, university of baghdad, 13. sarda, k.k., bhandari, a., pant, k.k., andsapna, j., 2012, "deep desulfurization of diesel fuel by selective adsorption over ni/al2o3 and ni/zsm-5 extruates", fuel, 93: 86-91. 14. li, j., hu, b, tan, j, and zhuang, j.,2013, "deep oxidative desulfurization offuels catalyzed by molybdovanadophospheric acid on aminofunctionalizedsba-15 using hydrogen peroxide as oxidant", transition met chem. 15. lanju, c., shaohui, g., and dishun, z.,2006, "oxidation of thiophenes over silica gel in hydrogen peroxide/formic acid system", chinese j.chem. eng., 14(6): 835-838. 16. peng, h.l, jian, s, and hua. z, 2007, "desulfurization using an oxidation /catalysis/adsorption scheme over h3pw12o40/sio2al2o3 ", petroleum chemistry, 47(6):452-456. 17. cui, s., ma, f., and wang, y., 2007, "oxidative desulfurization of model diesel oil over ticontaining molecular sieves using hydrogen peroxide"react.kinet.catal.lett 92 1 :155−163. 18. zhang, b., zongoxuan, j., li, j., zhang, y., lin, f., liu, y., and li, c., 2012,”catalytic oxidation of thiophene and its derivatives via dualactivation for ultra-deep desulfurization of fuels”, journal of catalysis, 287:5-12. 19. yu, f., and wang, r., 2013,“deep oxidative desulfurization of dibenzothiophene in simulated oil and real diesel using heteropolyanion-substituted hydrotalcite-like compounds as catalysts”, molecules, 18:1369113704. 20. yu, g., lu, s., chen, h., zhu, z., 2005, "diesel fuel desulfurization with hydrogen peroxide promoted by formic acid and catalyzed by activated carbon", carbon 43:2285-2294. 21. dehkordi, a.m., sobati, m.a., and nazem, m.a., 2009, "oxidative desulfurization of non – hydrotreated kerosene using hydrogen peroxide and acetic acid", chinese journal of chemical engineering 17(5):1-6. 22. sharipov, a. kh., nigmatullin, v.r., nigmatullin, i.r., and zakirov, r.v., 2006, "catalytic oxidation of sulfides in middle distillates from mediumsulfur crude", chemistry andtechnology of fuels and oils, 42(6): 452-461. 23. mamaghani, a.h., fatemi, s., and asgari, m., 2013,” investigation of influential parameters in deep oxidative desulfurization of reduction of sulfur compounds from petroleum fraction using oxidation-adsorption technique 48 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net dibenzothiophene with hydrogen peroxide and formic acid” ,international journal of chemical engineering, 1-10. 24. yanxiu, l., hua, s., and wenchao, z.,2013, ”oxidative desulfurization of model sulfur compound by potassium ferrate in the presence of phosphomolybdic acid catalyst” china petroleum processing and petrochemical technology, 15(1), :61-65. 25. niemantsverdriet, c. j. w., 2003, "concepts of modern catalysis and kinetics concepts of ",wileyvchverlaggmbbh& co. kgaa, weinheim. 26. zeinab, k. nassrullah., 2012, "preparation and formation of zeolite 5 a form local kaolin clay for drying and desulfurization of liquefied petroleum gas", m.sc. thesis inchemical engineering, university of baghdad. 27. hamsa, n.fadhil., 2013,"potential of rice husk for methylene blue dye removal from waste water", m.sc. thesis in chemical engineering, university of baghdad. 28. mohammed , s.z. h., 2004"study the efficiency of molecular sieves type 4a as drying agent", m.sc. thesis in chemical engineering, university of baghdad. 29. zhang, y., yang, y., han, h., yang, m., wang, l., zhang, y., jiang, z., li, c., 2012, "ultra-deep desulfurization via reactive adsorption on ni/zno: the effect of zno particle size on the adsorption performance", appliedcatalysis b: environmental 119-120:13-19. 30. xu, x., zhang, s., li, p., shen, y., 2014,"desulfurization of jet fuel in a fixed bed reactor at room temperature and ambient pressure using a novel selective adsorbent", fuel,117:499-508. iraqi journal of chemical and petroleum engineering vol.15 no.4 (december 2014) 89-201 issn: 1997-4884 heat transfer efficiency of different composite insulators amel muhson naji 1 , najah m. al-shuwaiki 2 and ezzet h. abdulsalam 2 1 department of optics techniques dijlah university college 2 refrigeration & air conditioning engineering department dijlah university college abstract this research aims to investigate the thermal performance of different thermal composite insulators, wrapped around a closed-loop copper pipe (clp). to achieve this aim a system was designed and manufactured. it is consisted of closed water tank insulated by rock wool, and supplied with two electric heaters, two thermostat, a flow meter, a water pump, digital temperature scales, and four series of (clp). six insulators were prepared namely; composites of impregnated fiberglass with elastoclad and foaming rubber (fer), impregnated fiberglass with elastoclad resin and polymeric membrane (fem), impregnated fiberglass with polyurethane thermoset resin and foaming rubber (fur), impregnated fiberglass with polyurethane thermoset resin and polymeric membrane (fum), fiberglass woven tape (f) , and foaming rubber tape (r). thermal conductivities of all composite specimens were measured by lee's disc device and their thermal performances were evaluated by measuring inlet and outlet temperature δtw at different flow rates. it was found from all test results that δtw decreased as flow rate increased. the optimum result was obtained for the (fer) insulator at flow rate 8 l/min where δtw = 0.8 o c (efficiency η = 99 %). thermal efficiency of the prepared insulators was according to the following sequence: fer > fem > fur > fum >r > f keywords: composite insulators; tube insulation; heat losses; thermal conductivity introduction energy consumption is an essential element in development and its considered as a major key in the generation of wealth. with the increase in the cost of the energy and the high energy consumed by some areas such as industrial, building, transportation and agriculture, these sectors especially building have recently received considerable attention on energy consumption because of heat losses, kaynakli [1]. while increased energy use clearly has many benefits, we are also becoming increasingly aware of the negative environments impacts of energy use. however, more efficient use of energy could reduce the negative impacts of energy consumption, while still allowing the same economic development, mustafa omer [2]. energy efficiency is understood to mean the utilization of energy in the iraqi journal of chemical and petroleum engineering university of baghdad college of engineering heat transfer efficiency of different composite insulators 90 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net most cost effective manner to carry out a manufacturing process or provide a service, whereby energy waste is minimized and the overall consumption of primary energy resources is reduced. there are many benefits of increased energy efficiency. these can broadly be categorized into financial/economic, environmental and social benefits, trianni, cagno, worrell, pugliese, and bohm [3,4]. insulation materials are extensively used to reduce the heat losses (or gains) from thermal systems like buildings, tubes and ducts, components of hvac installations, etc. in these systems, the insulation layers account for most of the thermal resistance between the hot (or cold) element/s and the environment, domínguez-muñoz, bond, abdou, and broin [58].insulation materials fall into two broad categories: organic and inorganic materials. the organic materials include polystyrene, polyurethane, phenolic foam, and polyethylene foam etc. the inorganic materials include mineral wool, calcium silicate, cellular glass, microporous silica, magnesia, ceramic fibre, vermiculite and perlite, persson, lingbin, wei, al-ajlan, and wei [9-13]. since, the main function of insulation is to reduce the heat transfer, the insulation material must have the appropriate characteristic to retard the transport of heat occurred by conduction, convection and radiation. conduction loss in insulation is negligible, keçebas [14]. various thermal insulation systems taking advantages of different types of thermal insulation materials on both organic (expanded plastics, wood, wool, cork, straw, and technical hemp) and inorganic basis (foamed glass, glass and mineral fibers) are being designed and tested, pavlik [15]. besides, most of the available studies focus on insulating buildings, uyguno_glu, kaur, al-turki, and tenpierik [16-19] and cold stores, soylemez, and kecebas [20, 21] because of the large potential for energy savings. these studies consider the flat plate or slab as the geometric configuration, presenting the large areas of roofs and façades. on the other hand, studies to improve thermal insulation for cylindrical geometry are few in spite of the extensive use of tube lines and cylindrical heat exchangers in refineries, chemical industry, district heating/cooling, and power plants, zaki, wechsatol, wechsatol, and kalyon [22-25]. therefore, the objective of the present work is to study the thermal performance of different insulators wrapped on a closed-loop copper pipe (clp) at different flow rates using water as a heat carrier. electrical heaters are used to supply the (clp) with hot water. six insulators were used namely; composites of impregnated fiberglass with elastoclad and foaming rubber (fer), impregnated fiberglass with elastoclad and polymeric membrane( fem), impregnated fiberglass with polyurethane thermoset resin and foaming rubber (fur), impregnated fiberglass with polyurethane thermoset resin and polymeric membrane(fum), fiberglass woven tape (f), and foaming rubber tape (r). the results of this study will provide (i) a basis for comparison between the used insulators (ii) environmental impacts caused by heat losses that occur during use of the heat distribution system. modeling and analysis 1. the structure of the piping system in our experiment heat transfer is carried out by the use of hot water flowing through a closed loop system where the heat is convected to the ambient air and then the hot water amel muhson naji, najah m. al-shuwaiki and ezzet h. abdulsalam -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 91 flows to a storage tank where it's reheated again. heat loss and temperature change of transfer tube lines are significantly influenced by (i) insulation, (ii) surrounding environment (ambient air) for tube, and (iii) tube structure. the hot water piping system considered in this study is shown in fig. 1 for a unit length of a long straight conduit segment, installed in a constant environmental temperature and constant thermodynamic properties at an appropriate mean temperature. the hot water for this system is pumped through the tube with a constant velocity under steady-state steady-flow control volume conditions. pressure drops due to the liquid flow friction is neglected in this study. 2. the heat loss calculation for the piping system heat losses occurred from hot water through piping system can be calculated by the following equation. q = ua (tav _ ta) = ua δt = δt/σ rthermal … (1) fig. 1 the hot water tube line with insulation where a is the total surface area of a tube, ta is the temperature of outside air, tav is the average design temperature of inside fluid, and u is the overall heat transfer coefficient. the total internal resistance of any piping system, σ rthermal, is equal to the summation of the surface resistances of convective heat transfer over the inside and outside surfaces of the tube and the total internal resistance of all layers of piping system is given as in holman, and cengel [26-27]. σ rthermal = rwater convection+ rcopper conduction+ r1-insulation conduction+...rninsulation+ rair convection = 1/hi ai+ln (ro/ri) /2π kl+ln (r1/ro) /2π k1l+… ln (rn/rn-1) / 2π knl+1/hoan …(2) where r1, r2, etc. are insulation layers of piping system radii. the length of the tube is l. the inside surface area of the tube is ai = 2πlri while the outside surface area of the tube is ao = 2πlro and the surface area of the last layer of piping system is an = 2πlrn: in this study, the total internal resistance of un-insulated piping system is σ run-insulated pipe = rwater convection + rcopper conduction + rair convection = 1/hi ai+ln (ro/ri) /2π kl +1/hoao …(3) and the total internal resistance of insulated piping system is the following form: σ rinsulated pipe = rwater convection+ rcopper conduction+ r1-insulation conduction + rair convection = 1/hi ai+ln (ro/ri) /2π kl+ln (r1/ro) /2π k1l +1/hoa1 … (4) the convection heat transfer coefficients for the inside and outside surfaces of piping system hi and ho are calculated as [26-28]: nu = 0.023 re 0.8 pr 0.3 … (5) ho = 1.32 (δts/do) 1/4 ... (6) heat transfer efficiency of different composite insulators 92 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net the difference between the overall heat transfer coefficients of uninsulated and insulated piping systems can be written as δu= uun-insu. pipe – uinsu. pipe. ... (7) for outer radii greater than the critical value any increase in insulation thickness will cause a decrease in a heat transfer [26]. so for any layer of insulation the outer radius must be larger than the critical radius which is defined as rc = kinsulation / ho ... (8) where rc is the critical radius of insulation. q = (tav – ta) / σ rthermal ... (9) qun-insu. pipe = (tav – ta) / σ run-insu. pipe .. . (10) qinsu. pipe = (tav – ta) / σ rinsu. pipe ... (11) qsave = qun-insu. pipe – qinsu. pipe ... (12) heat loss= (qsave/qun-insu. pipe)*100% ... (13) where ta is the temperature of the ambient air, tav is the average temperature of the fluid inside the tube (tav = (tin + tout)/2) experimental 1. materials the materials which are used in the experiment as insulators are: e-type fiberglass, bitumen membrane, rubber insulation foam tape, thermoset polyurethane (pu) resin, elastoclad, and rock wool. all the specifications are listed in the table 1: table 1: specification of the materials materials specifications e-type fiberglass  woven fabric of 0.25 mm thickness  aerial weight 270 g/m 2  density 2.5gm/cm 2 elastoclad resin  100% acrylic copolymer  heat reflective  volume solids approx. 60%,  thermal conductivity 0.19 w/( m.k)  specific gravity 0.86 ± 0.05  cure time 2-4 hours rock wool  not burn and bear high temperature up to 750°c.  coefficient of thermal conductivity is low 0.035 w/m .k self adhesive rubber foam tape  density ( ) 60~100kg/  temperature range (-24°c -+170°c) polyurethan e (pu)  unfilled thermoset resin  specific gravity1.03-1.5  water absorption (% weight increase)0.2 1.5  thermal conductivity (w/mk) 0.209 2. experimental set up and procedure the experimental setup as shown in fig. 2 consisted of galvanized water tank of dimensions (1*0.5*0.6) m insulated by rock wool. four 5m long copper tubes (99% purity) are used in the experiment. the tubes are bended http://www.efunda.com/units/convert_units.cfm?from=889&mrn=0%2e209#convinto amel muhson naji, najah m. al-shuwaiki and ezzet h. abdulsalam -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 93 by a tube processing machine (tubomat), tub 642 type, manufactured by tracto-technik gmbh & co.kg and made in germany. the internal diameter of the tube is 0.017m and the outer diameter is 0.019m. the thermal conductivity of the copper tube (k) is (385w/m.k). other equipments like two electric heaters of (3000 watt each.) as heat sources, two thermostats were used in the experiment. a flow meter (blue white, california, usa) of (1-4 gpm, and 2-16 lpm) to measure water flow rate in the copper tubes. electrical water pump, marques, made in china, model mkp 60-1, (voltage 220, 50 hz, power 0.5hp, 370 watt, maximum 40 lpm) is used to pump water from the tank. 1. galvanized tank of hot water 2. indicator of the level of water 3. temperature control board 4. water centrifugal pump 5. gate valve 6. four copper tubes 7. electric heater 8. water flow meter 9. connections between the tubes 10. tank rock wool insulator 11. input screw type thermocouple sensor 12. output thermocouple sensor fig. 2 schematic diagram of the apparatus digital temperature scales (redlion, usa) with eight thermocouple sensors (autonics sensor, korea) are used to measure water temperature at the inlet and outlet of the copper tubes. five gate valves are used to control the flow of water. 3. preparations of composite insulators different composite insulators were prepared and used for insulating the tubes and also machined to desire final dimension for thermal conductivity test as mentioned in 3.4. 3.1 preparation of fer a suspension of elastocladin water was prepared and stirred well for 10 min. fiber glass woven tape was impregnated with the above suspension. the suspension was used to impregnate glass fiber tape on a weight basis (60 /40). the suspensions were applied with a brush and the solvent was allowed to evaporate for 56 hours under ambient conditions. the dried impregnated tape so prepared was stacked over rubber foam tape, and placed between stainless steel plates. 3.2 preparation of fem fiber glass woven tape was impregnated and prepared as described in 3.1 .the bitumen membrane was shredded into tapes of 6 cm and 1500 cm length. the dried impregnated tape so prepared was stacked over the bituminous membrane tape – using a flame to melt the polyethylene layer to achieve good adhesion and placed between stainless steel plates. 3.3 preparation of fur fiber glass woven tape was impregnated with polyurethane thermoset resin on a weight basis 60/40 and the resin was treated as in 3.1. heat transfer efficiency of different composite insulators 94 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net 3.4 preparation of fum fiber glass woven tape was impregnated with polyurethane thermoset resin, dried and stacked over the shredded bituminous membrane tapes of 6 cm and 1500 cm length – using a flame to melt the polyethylene layer to achieve good adhesion. the dried impregnated tape so prepared was stacked over rubber foam tape, and placed between stainless steel plates. 4. measurement of thermal conductivity thermal conductivity of all specimens was measured by using lee's disc device (griffin & george/england) in university of technology. three copper discs (a, b, c) of 40 mm diameter x 12.25 mm thickness each are used in lee's device as shown in fig. 3. the insulator samples were machined to diameter 40 mm and thickness 3mm.the value of (e) and (k) were calculated according to the following equations. the different insulator composites; their thermal conductivity data and designation are shown in table 2. fig. 3: three copper discs (a, b, c) in lee's disc device table 2: insulators types, their designation and thermal conductivity values no insulators types designation 1 impregnated fiberglass with elastoclad and foaming rubber 0.01353 2 impregnated fiberglass with elastoclad and polymeric membrane 0.0635 3 impregnated fiberglass with polyurethane thermoset resin and foaming rubber 0.1383 4 impregnated fiberglass with polyurethane thermoset resin and polymeric membrane 0.1662 5 fiberglass roven tape 0.0396 ( ) ( ) … (14) ( ) ( ) ...(15) where q: amount of heat transfer (w). ( , , ):temperature of discs (a,b,c) respectively (°c). ( ): thickness of discs (a, b, c) respectively (mm). : thickness of sample (mm). r: radius of disc (mm). i: current (amp). v: supply voltage (volt). e: convection heat transfer coefficient (w/m 2 .°c). 5. measurement of heat loss the pump turned on and left for 15 minutes to make sure that all four tubes were filled in water. the water heated amel muhson naji, najah m. al-shuwaiki and ezzet h. abdulsalam -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 95 up to 80 o c and several runs were performed. in each run the inlet and outlet temperature of hot water at different flow rates for all four tubes were taken, by adjusting the flow rate valve and by using rtd (resistance temperature detector) sensor. results and discussion different resins were used as a matrix polymer for the impregnation of the fiber glass: 1elastoclad is a 100% acrylic waterproofing and heat reflective coating which is formulated with hollow core ceramic microspheres to dissipate and reflect heat and also provides a long lasting elastomeric waterproof resin. this resin as indicated by the supplier has many advantages: deadens sound, resists hail damage, and is fungus resistant.  resistant to chemicals and deterioration from hot weather conditions.  reduces radiant heat transmission from external surfaces by up to 92%.  protects metals from rust corrosion  the cured waterproof membrane is elastomeric and can tolerate substrate movement without cracking or flaking. polyurethane thermoset resin is also well known for its low thermal conductivity in the experiment, several runs were done and many data points were considered to draw different curves that illustrate the relations between the used parameters. the calculations were done as in the appendix. from fig. 4, it can be noticed that the least value of temperature difference between the inlet and outlet water flow is achieved when using fer insulator (impregnated fiberglass with elastoclad and foaming rubber). table 3 and fig. 5 show the temperature difference of inlet and outlet water of different insulated tubes at different flow rates of hot waters in tubes. for each run, the best sequence of insulators is fer, fem, fur, fum, r and f. it's also seen that as the flow rate increases the temperature difference decreases for the same insulators. fig. 4: temperature difference of different insulators table (3) temperature difference of inlet and outlet water in tubes of different insulators at different flow rate, k vr l/ min δtw (k) bla nk f r fu m fu r fe m fe r 0.5 29.6 12 8 6.1 5.2 5.1 5.0 2.0 27.4 9.5 6.6 5.3 4.5 4.1 3.3 4.0 23.4 8 6.5 4.4 3.5 2.7 2.4 6.0 18.5 7.1 6.4 4.3 2.7 2.3 1.6 8.0 17.9 6.5 6.2 3.7 2.2 1.5 0.8 0 5 10 15 20 25 insulation type t e m p e ra tu re d if fe re n ce , δ t w , k heat transfer efficiency of different composite insulators 96 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net fig. 6 shows and compares between the temperature difference values of the blank tube (without insulation) and the tube with fer insulation which has the smallest temperature difference. fig. 7 gives the relation between the temperature difference of the blank tube and the tube of fer insulation. table 4 shows the thermal conductivity, thermal resistance, the heat loss through tubes, the heat saved compared with an un-insulated tube (blank one), and the percent reduction which is calculated for the six insulators used. its seen that fer insulated tube has 77.7 % reduction in heat loss compared with the blank tube, so it is considered the best between the others. fig. 5: temperature difference of different insulators at different flow rate δtw (blank, without insulation) = 3.0855 δtw (fer) + 15.276 …(16) where δtw = tin – tout fig. 6: comparison of temperature difference between the blank and fer tube fig. 7: a plot of δt (blank tube) versus δt (fer insulated tube) table 4: saved heat and percent reduction for different insulators at 1 l/min insula tion type k, (w/m .k) resista nce r, (k/w) heat loss (w) heat save % reduc tion fer 0.013 1.4936 26.5 91.8 77.7 fem 0.02 0.97 37.7 80.6 68.12 fur 0.08 0.24 100.92 17.57 14.8 fum 0.085 0.228 103.9 14.5 12.2 r 0.09 0.21 108.39 10.05 8.49 f 0.095 0.204 109.8 8.6 7.2 blank 385 0.37 118.45 0.0 0.0 fig. 8 shows the relation between the saved heat and the percent reduction with respect to the types of insulators used. the best insulator is fer type where the heat saved and the percent 0 5 10 15 20 25 30 35 0.5 2 4 6 8 blan k fer t e m p e ra tu re d if fe re n ce , δ t w , k y = 3.0855x + 15.276 r² = 0.9221 0 5 10 15 20 25 30 35 0 2 4 6 δtw of fer δ t w o f b la n k amel muhson naji, najah m. al-shuwaiki and ezzet h. abdulsalam -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 97 reduction is 91.8 w and 77.7 % respectively. fig. 9 shows the heat loss for all types of insulators beside the blank tube without insulation. the minimum heat loss is 26.5 w which obtained when fer insulator is used while the maximum heat loss is 118.45 w for the un-insulated tube. it's noticed from the figure that the two composite insulators (fer and fem) are good insulators because of using the elastoclad suspension for impregnation. fig. 8 heat saved and percent reduction for several insulators at different flow rate (0.5, 2.0, 4.0, 6.0, 8.0 l/min) and for different insulators (fer, fem, fur, fum, r, m), the efficiency of each one is calculated according to the percent of the outlet temperature to the inlet temperature and it's found that fer efficiency (99 %) is the best at 8 l/min flow rate as shown in table (5) and fig. (10). η = (outlet temp. / inlet temp.) *100% ...(17) fig. 9 gradual heat loss of all insulators and the blank tube table 5: the efficiency η of different insulators at different flow rate, (%) vr l/min blank η f η r η fum η fur η fem η fer η 0.5 63 85 90 92.37 93.5 94.37 93.75 2.0 65.75 88.12 91.75 93.37 94.37 94.87 95.87 4.0 70 90 91.87 94.5 95.62 96.62 97 6.0 76.87 91.12 92 94.62 96.62 97.12 98 8.0 77.62 92.87 92.25 95.37 97.25 98.12 99 0 10 20 30 40 50 60 70 80 90 100 heat saved % reduction h e a t sa v e d ( w ) a n d p e rc e n t re d u ct io n insulation type 0 20 40 60 80 100 120 140 fer fe fu fu r f blan h e a t lo ss , w insulators heat transfer efficiency of different composite insulators 98 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net fig. 10: the efficiency of different insulators at different flow rate conclusions the appropriate insulation must be selected on the basis of temperature, thermal conductivity and other limiting factors that might limit application. the appropriate thickness must be determined for the particular application. from the results achieved it was concluded that: 1thermal insulators are necessary materials for minimizing heat loss and saving energy. 2temperature difference decreases as the flow rate of hot water increases. 3the efficiency and percent heat loss reduction of insulation for the prepared insulators was according to the following sequence: fer > fem > fur > fum > r > f 4there are three cases of heat transfer in tubes in the experiment i. forced convection heat transfer in hot water inside the tube. ii. conduction heat transfer through the wall of the copper tube and through the insulation layer. iii. and finally the free convection heat transfer from the outer surface of the tube to the ambient cold air. 5the emissivity of the copper material is very small (0.018), so the radiation heat loss from the outside surface of the tubes was neglected. 6the insulators fer and fem show high efficiency of insulation which explain the effect of using elastoclad. nomenclature symbols a total surface area of tube (m 2 ) ac cross sectional area (m 2 ) ai inside surface area of the tube (m 2 ) ao outer surface area of the tube (m 2 ) an outside surface area of the last layer of piping system (m 2 ) thickness of discs (a, b, c) respectively (mm) thickness of sample (mm) e convection heat transfer coefficient in lee's disc device (w/m 2 . °c). f fiberglass roven tape g gravitational acceleration (m/s 2 ) gr grashof number hi, ho heat transfer coefficients of water inside the tube and ambient air (w/m 2 .k) i current (amp) k thermal conductivity of the copper tube (w/m.k) k1, k2 thermal conductivities of insulation layers of piping system (w/m.k) ki thermal conductivity of the fluid inside the tube (w/m.k) ko air conductivity (w/m.°k) nu nusselt number pr prandtl number q amount of heat transfer (w) qr radiation rate of heat loss (w) 50 60 70 80 90 100 0.5 l/min 2 l/min 4 l/min 6 l/min 8 l/min e ff ic ie n cy η , % insulation type amel muhson naji, najah m. al-shuwaiki and ezzet h. abdulsalam -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 99 r foaming rubber tape rthermal thermal resistance (°c/w) r radius of disc (mm) r1, r2 radii of insulation layers (m) ra rayleigh number re reynold number rp total internal resistance of any piping system (k/w) , , temperature of discs (a, b, c) respectively (°c) ta temperature of the surrounding ambient air (k) tav average temperature of inside fluid (k) tf film temperature (k) ts temperature of the surface (k) u overall heat transfer coefficient (w/m 2 .k) u velocity of water (m/s) v supply voltage (volt) vr volumetric flow rate (l/min) greek symbols β volumetric expansion (k -1 ) δ difference between two values δts the temperature difference between the tube surface and the ambient air (k). µ dynamic viscosity (kg/m.s) ν kinematic viscosity (m 2 /s) ρ water density (kg/m 3 ) σ summation σ stefan boltzman constant (w/m 2 .k 4 ) є emissivity of the copper η efficiency of insulator subscripts 1 first insulation layer 2 second insulation layer c cross section i inside the tube n insulation number n o outside the tube superscript n the power value of prandtl number abbreviations clp closed-loop pipe fem impregnated fiberglass with elastoclad and foaming rubber fum impregnated fiberglass with polyurethane thermoset resin and polymeric membrane fur impregnated fiberglass with polyurethane thermoset resin and foaming rubber hvac heating, ventilation, and air conditioning references 1o. kaynakli, a study on residential heating energy requirement and optimum insulation thickness, renewable energy, vol. 33, pp. 11641172, 2008. 2a. mustafa omer, energy environment and sustainable development, renewable and sustainable energy reviews, vol. 12(9), pp.2265-2300, 2008 3a.trianni, e. cagno, e. worrell, and g. pugliese, empirical investigation of energy efficiency barriers in italian manufacturing smes, energy, vol. 49 , pp. 444458 ,2013. 4b. bohm production and distribution of domestic hot water in selected danish apartment buildings and institutions, analysis of consumption, energy efficiency and the significance for energy design requirements of buildings. energy conversion and management, vol. 67 pp. 152–159, 2013. 5f. domínguez-muñoz, b.anderson, j.m. cejudo-lópez, and a. carrillo andrés,uncertainty in the thermal conductivity of insulation materials. eleventh international heat transfer efficiency of different composite insulators 100 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net ibpsa conference glasgow, scotland july 27-30, 2009. 6d. e.m. bond, w. w. clark, and m. kimber., configuring wall layers for improved insulation performance, applied energy vol. 112,pp 235–245, 2013. 7a. abdou, and i. budaiwi, the variation of thermal conductivity of fibrous insulation materials under different levels of moisture content, construction and building materials, vol. 43, pp. 533–544, 2013. 8e. o broin, e. mata , a. göransson, and f. johnsson, the effect of improved efficiency on energy savings in eu-27 buildings.energy,vol,1,pp.134– 148,2013. 9c. persson, m. fröling and m. svanström , life cycle assessment of the district heat distribution system ,part 3: use phase and overall discussion, int. j. lca vol. 11 (6), pp. 437–446, 2006. 10j. shi, lingbin lu, w. guo,yujia sun, and y. cao, an environment-friendly thermal insulation material from cellulose and plasma modification, journal of applied polymer science ,vol 130 (5), pp. 3652–3658, 2013. 11g. wei , y. liu, x. zhang, and x. du, radiative heat transfer study on silica aerogel and its composite insulation materials, journal of noncrystalline solids vol. 362 ,pp. 231– 236,2013. 12s. a. al-ajlan, measurements of thermal properties of insulation materials by using transient plane source technique, applied thermal engineering ,vol. 26, (17–18), pp. 2184–2191, 2006. 13ga. wei , x. zhang , and f. yu, thermal conductivity of xonotlite insulation material, int. j. thermophys, vol. 28, pp. 1718–1729, 2007. 14a. keçebas, m. ali alkan , and m. bayhan , thermo-economic analysis of tube insulation for district heating piping systems , applied thermal engineering, vol. 31 pp. 3929-3937,2011. 15z. pavlik, and r. cerny, hygrothermal performance study of an innovative interior thermal insulation system, applied thermal engineering, vol. 29, pp. 1941-1946, 2009. 16t. uyguno_glu, and a. keçebas¸ , lcc analysis for energy-saving in residential buildings with different types of construction masonry blocks, energy and buildings, vol. 43, pp. 2077-2089, 2011. 17j. kaur, s.p. singh, r.l. sawhney, and m.s. sodha, optimum layer distribution of a building component, international journal of energy research, vol. 15, pp. 11-18, 1991. 18a.m. al-turki, and g.m. zaki, cooling load response for building walls comprising heat storage and thermal insulation layers, energy conversion and management, vol. 32, pp. 235-247, 1991. 19m. j. tenpierik, and e. hasselaar, reflective multi-foil insulations for buildings: a review, energy and buildings, vol. 56, pp. 233–243, 2013. 20m.s. soylemez, and m. unsal, optimum insulation thickness for refrigeration applications, energy conversion and management, vol. 40, pp. 13-21, 1999. 21a. kecebas, and m. kayveci, effect on optimum insulation thickness, cost and saving of storage design temperature in cold storage in turkey, energy education science and technology part a: energy science and research, vol. 25, pp. 117-127, 2010. 22g.m. zaki, and a.m. al-turki, optimization of multi-layer thermal file:///c:/users/amel/desktop/amel%20+nejah/new%20folder/the%20effect%20of%20improved%20efï¬�ciency%20on%20energy%20savings%20in%20eu-27%20buildings.htm file:///c:/users/amel/desktop/amel%20+nejah/new%20folder/the%20effect%20of%20improved%20efï¬�ciency%20on%20energy%20savings%20in%20eu-27%20buildings.htm file:///c:/users/amel/desktop/amel%20+nejah/new%20folder/the%20effect%20of%20improved%20efï¬�ciency%20on%20energy%20savings%20in%20eu-27%20buildings.htm file:///c:/users/amel/desktop/amel%20+nejah/new%20folder/the%20effect%20of%20improved%20efï¬�ciency%20on%20energy%20savings%20in%20eu-27%20buildings.htm file:///c:/users/amel/desktop/amel%20+nejah/new%20folder/the%20effect%20of%20improved%20efï¬�ciency%20on%20energy%20savings%20in%20eu-27%20buildings.htm http://onlinelibrary.wiley.com.tiger.sempertool.dk/doi/10.1002/app.v130.5/issuetoc http://onlinelibrary.wiley.com.tiger.sempertool.dk/doi/10.1002/app.v130.5/issuetoc http://www.sciencedirect.com.tiger.sempertool.dk/science/article/pii/s1359431106001256 http://www.sciencedirect.com.tiger.sempertool.dk/science/journal/13594311 http://www.sciencedirect.com.tiger.sempertool.dk/science/journal/13594311 http://www.sciencedirect.com.tiger.sempertool.dk/science/journal/13594311/26/17 amel muhson naji, najah m. al-shuwaiki and ezzet h. abdulsalam -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 101 insulation for tube lines, heat transfer engineering, vol. 21, pp. 63-70, 2000. 23w. wechsatol, s. lorente, and a. bejan, tree-shaped insulated designs for the uniform distribution of hot water over an area, international journal of heat and mass transfer, vol. 44, pp. 3111-3123, 2001 24w. wechsatol, s. lorente, and a. bejan, development of tree-shaped flows by adding new users to existing networks of hot water tubes, international journal of heat and mass transfer, vol. 45, pp. 723-733, 2002. 25m. kalyon, and a.z. sahin, application of optimal control theory in tube insulation, numerical heat transfer part a: applications, vol. 41, pp.391-402, 2002. 26j.p. holman, heat transfer, mc graw-hill international edition, tenth edition, 2010 27y. a. cengel, "heat transfer", a practical approach, second edition, mc graw-hill companies inc. singapore, 2003. appendix case study heat loss calculation for a copper tube is: thermal conductivity, k = 385 w/m.k average surface temperature of the tube, ts = 65°c (338 k) ambient air temperature, ta = 25°c (298 k) average water temperature in the tube, tav = 70 °c δt = tav – ta = 45 °c δts = ts – ta = 40 °c inner area of the tube, ai = πdil = π (0.017) *5 = 0.267 m 2 outer area of the tube, ao = πdol = π (0.019) *5 = 0.298 m 2 outer area of the first insulator layer, a1 = πd1l = π (0.035) * (5) = 0.546 m tube length = 5m; inner diameter = 0.017 m and outer diameter = 0.019 m number of tubes = 4 radiation heat transfer qr = σ є ao (ts 4 ta 4 ) = 5.669 * 10 -8 * 0.018 * 0.298 (338 4 – 298 4 ) =1.57 w which is neglected because it's a small value where qr = radiation rate of heat loss, w ao = outer surface area of the tube, m 2 ts = temperature of the surface, k ta = temperature of the surrounding ambient air, k є = emissivity of the copper surface, 0.018 σ = stefan boltzman constant = 5.669 *10 -8 w/m 2 .k 4 total heat loss = q= ua (tav _ ta) = uaδt ∑ heat transfer coefficient of hot water inside the tube: hi = 0.023* re 0.8 * prn ki/di n = 0.4 for heating and 0.3 for cooling for water flow inside the tube at tav = 70°c, the water properties [26] µ = 4.0678 *10 -4 kg/m.s ρ = 977.89 kg/m 3 ki = 0.6638 w/m.k pr = 2.5699 vr (volumetric flow rate) = 1l/min u = vr/ac = 1 * 10 -3 /60 ((π/4) (0.017) 2 ) = 0.073m/s re = ρ u di/µ = 977.89 * (0.073) (0.017)/ 4.0678 *10 -4 = 3006.58 since re is greater than the critical re of tubes (2300), the flow is turbulent nu = hi di/ki = 0.023* re 0.8 * prn = 0.023 * 3006.58 0.8 * 2.5699 0.3 = 18.499 hi = (ki/di) * 0.023* re 0.8 * prn = (0.6638/ 0.017) * 0.023 * 3006.58 0.8 * 2.5699 0.3 = 722.35 w/m 2 .k to calculate ho for the ambient air with the outside surface area, air properties are found at tf as [26, 27]: film temperature, tf =( ts + ta)/2 = (65+25)/2 = 45 °c = 318 °k heat transfer efficiency of different composite insulators 102 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net volumetric expansion, β = 1/tf = 1/318 = 3.144 * 10 -3 k -1 gravitational acceleration, g = 9.81 m/s 2 kinematic viscosity, ν = 17.5152 * 10 -6 m 2 /s prandtl number, pr = 0.704 the outer insulator surface diameter, d1 = 0.035 m air conductivity, ko = 0.031 w/m. k grashof number, gr = g β (ts – ta) do 3 /ν 2 = 9.81 * 3.144 * 10 -3 * (65 – 25) * 0.019 3 /(17.5152 * 10 -6 ) 2 = 27583 rayleigh number, ra = gr * pr = 27583 * 0.704 = 19418.46 convection heat transfer coefficient at the ambient air outside the tube is calculated according to the following equation: ho = 1.32 (∆ts/d) 1/4 for 10 4 < ra < 10 9 ho = 1.32 * (40/ 0.019) 1/4 = 8.94 w/m 2 .k q = (tav – ta) / σ rthermal = δt/ sum of thermal resistances σ rthermal (un-insulated tube) = rwater convection + rcopper conduction + rair convection σ rthermal (un-insulated tube) = 1/hi ai + ln (do/di) / 2π kl +1/hoao = 1/(722.35 * 0.267) + ln (0.019/0.017) /2π * 385 *5 + 1/(8.94 *0.298) = 0.3799 °c/w total heat loss of un-insulated tube, q un-insulated = 45/ 0.3799 = 118.425 w for insulated tube with fer insulation (k = 0.01353) σ r (insulated tube) = rwater convection+ rcopper conduction+ r1-insulation conduction+ rair convection = 1/hi ai + ln (do/di) / 2π kl + ln (d1/do) / 2π k1l + 1/hoa1 = 1/(722.35 * 0.267) + ln (0.019/0.017) /2π * 385 *5 + ln (0.035/0.019) / (2π *0.01353 *5) + 1/(8.94* π * 0.035* 5) = 0.005185 + 0.000009196 + 0.2744 + 0.2 = 1.7 °c/w total heat loss of insulated tube, q insulated = 45/1.7= 26.43 w qsave = qun-insulated pipe – qinsulated pipe = 118.425 – 26.43 = 91.989 w reduction in heat loss % = [(qun-insulated pipe – qinsulated pipe) / qun-insulated pipe] * 100 % = (91.989 / 118.425) * available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.21 no.1 (march 2020) 39 – 44 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: ayat ahmed jasim, email: ayat.ahmed16@yahoo.com , name: abdul aali al-dabal, email: resaldabaj@yahho.com , name: aqeel s. al-adili, email: aqeel_adili@hotmail.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. water injection for oil recovery in mishrif formation for amarah oil field ayat ahmed jasimª, abdul aali al-dabaj a and aqeel s. al-adili b ªuniversity of technology/petroleum technology department b university of technology/building and construction department abstract water injection, as the secondary oil recovery process, is the most important technology for incremental oil recovery from petroleum reservoirs. kappa work station software (rubis) was used for making the numerical model and history matching. in this research, suggest two cases to enhance pressure and make a comparison in the production of oil and the reservoir pressure for two case studies where the water was not injected in the first case study but adding new vertical wells while other case water is injected. the results of this work represent that if the water is not injected, the reservoir model that has been upgraded and it can produce only 2.9% of the original oil in place. this case study also represents a drop in reservoir pressure, which was not enough to support oil production. thus, the implementation of water injection in the second case study of the average reservoir pressure may support, which led to an increase in oil production by up to 5.5% of the original oil in place. so the case two can be considered the best scenario to develop mishrif reservoir of amarah oil field in the next 10 years from (2020-2030) by water injection method through drilling 18 vertical wells in addition to 6 original wells and 8 injection well using inverted nine-spot pattern which has the best recovery factor 5.5% and keep the pressure (3670 psia) above bubble pressure (2731 psia) to producing oil only so that, the use of water injection is a useful way to increase oil production. keywords: history matching, amarah, water injection, mishrif received on 14/10/2019, accepted on 12/11/2019, published on 30/03/0220 https://doi.org/10.31699/ijcpe.2020.1.6 1introduction 1.1. history matching history matching is defined as the work of modifying a model of the reservoir so that it almost reproduces the past behavior of a reservoir this is common use in the oil and gas industry so as to make a reasonable future prediction. reservoir engineers analyze the variation between the simulated and observed value and manually change one or a few parameters at a time in order to improve the match.in such an approach, reservoir variables are updated manually and oftentimes in two steps: the pressure matching and the saturation matching ‎[1], ‎[2] the nature of this type of data matching, in general, depends on the engineer's experience. the economic feasibility of a petroleum recovery process is greatly affected by the reservoir production performance under the current and future operating conditions. therefore the estimation of the past and present reservoir performance and forecast of its future are important in the reservoir management process. during history matching the past performance of the reservoir is simulated and the model is updated in order to match actual historical performance. the model corresponding to the final date should be supposed to accurately represent the reservoir and be able to predict reservoir performance ‎[3]. 1.2. water injection when the primary oil recovery step produces no more oil, water injection is the most applicable technique to enhance oil production from reservoirs. not only that also because of the minimum cost of water, as well as the water properties that help sweep the trapped oil efficiently. one of the main problems of this process is the low volume of effective controlling water, especially in heterogeneous reservoirs ‎[4]. when the reservoir pressure is decreased and the rate of oil produced is reduced. water is injected to enhance pressure, as some production wells are converted into injection wells. the pressure preservation mechanism in the reservoir is prepared as secondary oil recovery and displays a recovery factor ranging from 20 to 50%, depending on the properties of porous media and the characteristics of liquids. moreover, water injection is used largely because of the general availability of water, properly water is injected and the ability to propagate water through the formation of loading oil and the effective displacement of oil ‎[5]. https://doi.org/10.31699/ijcpe.2020.1.6 a. a. jasim, et al. / iraqi journal of chemical and petroleum engineering 21,1 (2020) 39 44 04 the minerals suspended in water injection should be minimized to ensure that no rock of the reservoir is clogged, due to the reaction of barium sulfate and strontium in unreacted water with injected water sulfate ions, which increases the volume of barium sulfate and steroid formation of pipe production and / or connection of reservoir rock around the production well ‎[6]. oil recovery technology has become an increasingly important problem in fluid management products, including disposal or water production. the development of oil and gas fields takes different types and shapes belong to the conditions and productivity associated with the hydrocarbon reservoir, where planning and management using a different process and advanced technology in implementation at low cost and risk, and therefore implementation depends on financial and human resources technical. resources with increased investment in capital and employment over time to increase the economic recovery of oil ‎[7]. 1.3. amarah oil field amarah oil field is located in maysan city, about (10 kilometer) south-west of amarah city and (10 kilometer) north-west of halafaya field and south-east of kumait field about (30km) ‎[8] as seen in fig. 1. this field lies on the unstable shelf at the mesopotamian basin. this field currently has 15 wells. fig. 1. location map for amarah oil field ‎[9] mishrif formation is an unstable shelf at the mesopotamian basin is where situated based on iraq tectonic zones ‎[10] such setting has an impact on the depositional setting, fracture intensity and structural style. the structure of mishrif contains a single anticline with axis trending north west-south east. the reservoirs of mishrif formation (cenomanian-early turonian) in the oil field contain compact limestone, chalky limestone, porous limestone and shale with chert at bottom of the formation. the lower boundary related to mishrif formation represents the change from basinal rumaila formation to the shallow open marine facies. it is a conformable surface ‎[11]. khassib formation is considered as the upper boundary of mishrif formation; such boundary is truncated through unconformity surface which separates the middle from late cretaceous ‎[12]. the mishrif formation can be defined as an overall progradational marine shelf sequence. following deposition related to transgressive shales and limestones of the formations of rumaila and ahmadi, rudist reefs and additional associated buildups which represent deposition of mishrif formation. it occupies one-third of iraqi reserves within rudist-bearing stratigraphic units ‎[11]. late cenomanian to the early turonian has been an age of advantageous conditions around the world for overhead organic productivity has been the main element that controls the location, progress and growth of buildup ‎[13]. the reservoir is composed of two main sedimentary cycles that suddenly ended via unconformity that separate mishrif formation from overlying khassib formation the cenomanian-early turonian ‎[11]. the mishrif formation has been considered as an essential reservoir and has been divided into seven reservoir units which are ma, mb11, mb12, mb13, mb21, mc1, mc2 and these units separated barriers. 2methodology 1collection of the required data such as well logs and core data, this data include porosity, permeability, capillary pressure, and relative permeability. 2building 3d geological modeling by using petrel software through the volumetric method, first of all, gathering the data related to wells (wellheads and well tops) from fourteen wells then input the map of mishrif formation and made a polygon. after that imports well log (porosity and saturation) for distribution through the reservoir also find the oilwater contact finally entered the value of bo to find oil in place. 3inputting the results of the geological model and other data such as fluid properties pvt data and pressure measurements from the final well reports into the software. 4building a numerical model by kappa work station ( rubis) software for suggested mishrif formation with the intention of representing reservoir performance and obtains oil in place. 5the production data that gathered from the source (amarah oil field will be imported to rubis software as daily oil production, which we had six wells only producing from mishrif formation in amarah oil field (am1,am-8,am-9,am-11,am-13and am14). the first production started in february 2011 from am-1 until 2018. also, the pressures reading which we had six reading only will be imported to the software. 6making a history matching by comparing the historical field production and the pressures to estimated values 7making a development plan, this made by suggestion two cases and made comparison between them: first a. a. jasim, et al. / iraqi journal of chemical and petroleum engineering 21,1 (2020) 39 44 04 case adding new vertical wells in addition to original six wells to the formation and producing from the main units ma and mb11 while the second case making water injection using an inverted nine-spot pattern. 3results and discussion from the geological model in petrel software, the original oil in place was 926mmstb. after that kappa workstation software (rubis) was used to make history matching. the production data for six wells have been entered with porosity, saturation, permeability and compressibility to making a history matching to find oil in place. the history matching was made and the original oil in place was 1025 mmstb so that the percentage error is low value. the figures below we have been get it from the program about history matching which represents that the dashed brown line shows the pressure match while dark blue line represents the value of pressure while the green line show the production rate values, blue line show water rate and red line show the gas rate vs time fig. 2 to fig. 7 show the history match for pressure and oil, water and gas rate for six wells in fig. 2 and fig. 4 there is not history match pressure 100% because maybe there is error in permeability data.while in fig. 3 in well am-11 and fig. 5 we haven„t any pressure data. then in fig. 6 and fig. 7, there is a history match pressure 100%. fig. 2. history match of am-1 fig. 3. history match of am-11 fig. 4. history match of am-13 fig. 5. history match of am-14 fig. 6. history match of am-8 fig. 7. history match of am-9 a. a. jasim, et al. / iraqi journal of chemical and petroleum engineering 21,1 (2020) 39 44 04 case 1: adding 26 vertical wells producing from unit ma & mb11 only: in this case, drilling 26 new vertical wells instead of horizontal or directional, because the vertical is easy to drill and less cost while horizontal and directional is cost also exhausting the pressure rapidly because producing more than vertical. the wells were suggested which producing from two units ma and mb11 , these wells perforated in depth between (9479.5289810.48)ft from the original well in the map the distance between each well will be 1000ft as suggested in this research. as displayed in fig. 8, the time for running stated from (2/1/2011 to 31/12/2030), the cumulative production rate of 26 wells and the original 6 wells will be 30303800 stb and the pressure value drop to 3985.75 psia and recovery factor is 0.029 at the end of 2030 as displayed in fig. 9. calculated by kappa (rubis) software after importing the geological model (porosity, water saturation, permeability) and entering (permeability values, pvt data, production data and pressure) the same procedures well will be adopted for the second case. fig. 8. the distribution of wells in case1 fig. 9. the cumulative liquid production, pressure, recovery factor vs. time for case1 case 2: 24 vertical wells production and 8 injection wells: in this case, water injection was made and will be used inverted nine-spot pattern so the cumulative production rate of 26 wells and the original 6 wells became 57031500.00 stb fig. 10. , the pressure was dropped to 3670.36 psia and the recovery factor was 0.055 as in fig. 11. fig. 10. the distribution of wells in case2 fig. 11. the cumulative liquid production, pressure, recovery factor vs. time for case 2 fig. 12, fig. 13, fig. 14 and fig. 15 represented the two cases as discussed above and show the change in values before and after used water injection .it show that the two cases was important to develop the reservoir but in case one the pressure was dropped to 3985.75 psia while the production was little through those years. while case two when we used the water injection method the pressure dropped under the value of case one while the production increased. case 2 represents the optimum scenario to develop the field in the future by using the water injection method through drilling 18 vertical wells in addition to 6 original wells and 8 injection wells which keep the reservoir producing above the saturation pressure for a long time also the water could re-injected. a. a. jasim, et al. / iraqi journal of chemical and petroleum engineering 21,1 (2020) 39 44 04 the value of pressure started from 5514 psi in 2011 then fall off to 3670 psi in 2030 also the recovery factor was 5.5% which is controlled in ooip also it had a water cut 43.3% because the reservoir is supported by bottom aquifer made the value increased comparison to case without injection method also average production rate was 8020 stb/d. fig. 12. water cut vs. time for two cases fig. 13. cumulative oil production vs. time for two cases fig. 14. presuure vs. time for two cases fig. 15. recovery factor vs. time for two cases 4conclusion 1water injection technique was used to develop the reservoir because the type of oil was heavy also it easy way rather methods were difficult and need more data and cost. 2the case two can be considered the best scenario to develop mishrif reservoir of amarah oil field in the next 10 years from (2020-2030) by water injection method through drilling 18 vertical wells in addition to 6 original wells and 8 injection well using inverted nine-spot pattern which has the best recovery factor 5.5% and keep the pressure (3670 psia) above bubble pressure (2731 psia) to producing oil only. 3the development case studies in this research have been important factors for supporting the original driving mechanism in petroleum reservoirs so that the field can continue producing for a long time. in particular, this research has clarified that water injection is one of the most important pressure enhancement techniques for increasing oil production. 4the drawback of using the water injection method is the expected large production of water which could prevent the oil from being produced. however, the produced water can be useful for re-injection processes which will provide the cost of drilling new water wells and this will also protect the environment from being polluted by the produced reservoir water. 5in this field, more cases can be a suggestion to increase oil production from the existing oil wells rather than depleting new petroleum reservoirs. references [1] mattax, c. c. and dalton, r. l. 1990. reservoir simulation, vol. 13. richardson, texas, usa: monograph series, spe. [2] saleri, n. g., toronyi, r. m. and snyder, d. e. 1992. data and data hierarchy. journal of petroleum technology 44 (12): 1286 – 1293. paper spe-21369pa. https://store.spe.org/reservoir-simulation-p70.aspx https://store.spe.org/reservoir-simulation-p70.aspx https://store.spe.org/reservoir-simulation-p70.aspx https://www.onepetro.org/journal-paper/spe-21369-pa https://www.onepetro.org/journal-paper/spe-21369-pa https://www.onepetro.org/journal-paper/spe-21369-pa https://www.onepetro.org/journal-paper/spe-21369-pa a. a. jasim, et al. / iraqi journal of chemical and petroleum engineering 21,1 (2020) 39 44 00 [3] gilman, j. r. and ozgen, c. 2013. reservoir simulation: history matching and forecasting. richardson, texas, spe. [4] a amiri, ak manshad "assessment the effect of water injection on improving oil recovery inx field." [5] m asadollahi "waterflooding optimization for improved reservoir management." norwegian university of science and technology (ntnu), department of petroleum engineering and applied geophysics, trondheim, norway (2012). [6] a. faiq al-alawy and j. jabbar madlool, “coagulation/ flocculation, microfiltration and nanofiltration for water treatment of main outfall drain for injection in nasiriyah oil field”, ijcpe, vol. 15, no. 4, pp. 47-66, dec. 2014. [7] g. n.jreou, “increasing of oil field productivity by implementation of re-entry horizontal injection well, case study”, ijcpe, vol. 13, no. 3, pp. 17-34, sep. 2012. [8] khanawi, m.a, abdul-ahad, r.j., sari, j.r., abdulsaheb, h., mohamed, a.h., jaafer, k.h., salman, s.j., geological evaluation study for amara field, iraqi oil explorations company., 2010. [9] al-ameri, t.k., al-jubouri, n.m., murtadha j. isa, and al-azzawi, r.e., hydrocarbons generation potential of the jurassic-lower cretaceous formation, ajeel feeld, iraq. arab j geosci springer pp.37253735, 2013. [10] vk sissakian, sfa fouad "geological map of iraq, scale 1: 1000 000, 2012." iraqi bulletin of geology and mining 11, no. 1 (2015): 9-16. [11] aqrawi, a.a.m., t.a. mahdi, g.h. sherwani, and a.d. horbury, characterization of the midcretaceous mishrif reservoir of the southern mesopotamian basin, middle east conference and exhibition, manama, bahrain ,2010. [12] jassim, s.z. and goof,j.c., geology of iraq . dolin ,prague and moravian museum,brno (czech republic), 341p.2006. [13] vanbuchem, f.s.p., razin, p., homewood, p.w., oterdoom, w.h., and philip, j.m., stratigraphic organization of carbonate ramps and organic-rich intra shelf basins: natih formation (middle cretaceous) of northern oman. aapg bulletin, v.86,pp.21-53, 2002. في تكوين المشرف لحقل العمارة النفطي النفط حقن الماء الستخالص 2عقيل العادلي و 1عبدالعال الدباج, 1ايات احمد جاسم / قسم تكنولوجيا النفط ةلجامعة التكنولوجيا1 /قسم البناء واالنشاءات ةالجامعة التكنولوجي2 الخالصة يعد حقن الماء من أىم التقنيات لتعزيز إنتاج النفط من مكامن النفط. في ىذا البحث ، تم تطوير المكمن النفطي لمحاكاة المكمن. تم استخدام ىذا النموذج لمقارنة kappa work station (rubis)باستخدام برنامج بئر عمودية باالضافة الى االبار الرئيسة 11إنتاج النفط وضغط المكمن لحالتين حيث تم في الحالة االولى حفر الموجود بالمكمن ولم يتم حقن الماء لكن في الحالة الثانية تم حقن الماء فأظيرت نتائج ىذا العمل أنو إذا لم يتم ٪ فقط من النفط األصمي في المكمن. كذلك أظيرت 2.2حقن الماء ، فإن نموذج المكمن المطّور يمكن أن ينتج الذي لم يكن كافًيا لدعم إنتاج النفط. في الحالة الثانية ، تم المكمندراسة الحالة ىذه أيًضا انخفاًضا في ضغط ٪ من النفط 5.5ى إلى زيادة إنتاج النفط ليصل إلى المكمن مما أد ضغطتطبيق حقن الماء فقد تم دعم متوسط سنوات من 10األصمي في المكمن. وبالتالي ، فان الحالة الثانية ىي االفضل لممحافضة عالمكمن لالنتاج لفترة فوق psia 3670ابار حقن والحفاظ عمى المكمن بضغط 1بئر عمودية و 11من خالل حفر 2030الى 2020 فإن تطبيق حقن الماء ىو تقنية مفيدة لزيادة إنتاج النفط. لذلك psia2231 ضغط التشبع الكممات الدالة3 التطابق، العمارة، حقن الماء،المشرف https://store.spe.org/reservoir-simulation-history-matching-and-forecasting-p844.aspx https://store.spe.org/reservoir-simulation-history-matching-and-forecasting-p844.aspx https://store.spe.org/reservoir-simulation-history-matching-and-forecasting-p844.aspx https://www.semanticscholar.org/paper/assessment-the-effect-of-water-injection-on-oil-inx-amiri-manshad/8ebca7d06cb0ece0d3abb2f06c7e5e47f123370b https://www.semanticscholar.org/paper/assessment-the-effect-of-water-injection-on-oil-inx-amiri-manshad/8ebca7d06cb0ece0d3abb2f06c7e5e47f123370b https://www.semanticscholar.org/paper/assessment-the-effect-of-water-injection-on-oil-inx-amiri-manshad/8ebca7d06cb0ece0d3abb2f06c7e5e47f123370b 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http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/297 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/297 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/297 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/297 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/297 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/338 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/338 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/338 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/338 https://link.springer.com/article/10.1007/s12517-012-0636-0 https://link.springer.com/article/10.1007/s12517-012-0636-0 https://link.springer.com/article/10.1007/s12517-012-0636-0 https://link.springer.com/article/10.1007/s12517-012-0636-0 https://link.springer.com/article/10.1007/s12517-012-0636-0 http://ibgm-iq.org/ibgm/index.php/ibgm/article/view/263 http://ibgm-iq.org/ibgm/index.php/ibgm/article/view/263 http://ibgm-iq.org/ibgm/index.php/ibgm/article/view/263 http://www.searchanddiscovery.com/pdfz/documents/2010/50264aqrawi/ndx_aqrawi.pdf.html http://www.searchanddiscovery.com/pdfz/documents/2010/50264aqrawi/ndx_aqrawi.pdf.html http://www.searchanddiscovery.com/pdfz/documents/2010/50264aqrawi/ndx_aqrawi.pdf.html http://www.searchanddiscovery.com/pdfz/documents/2010/50264aqrawi/ndx_aqrawi.pdf.html http://www.searchanddiscovery.com/pdfz/documents/2010/50264aqrawi/ndx_aqrawi.pdf.html https://trove.nla.gov.au/work/28903832?q&versionid=35183895 https://trove.nla.gov.au/work/28903832?q&versionid=35183895 https://trove.nla.gov.au/work/28903832?q&versionid=35183895 https://pubs.geoscienceworld.org/aapgbull/article-abstract/86/1/21/39938 https://pubs.geoscienceworld.org/aapgbull/article-abstract/86/1/21/39938 https://pubs.geoscienceworld.org/aapgbull/article-abstract/86/1/21/39938 https://pubs.geoscienceworld.org/aapgbull/article-abstract/86/1/21/39938 https://pubs.geoscienceworld.org/aapgbull/article-abstract/86/1/21/39938 iraqi journal of chemical and petroleum engineering vol.15 no.1 (march 2014) 18 issn: 1997-4884 evaluation of sodium chloride and acidity effect on corrosion of buried carbon steel pipeline in iraqi soil qasim sulaiman 1 , ali al – taie 2 , dahlia mohamed hassan 3 and commission of research and industrial development 4 1 chemical engineering department, collage of engineering, university of nahrain, baghdad, iraq 2, 3 chemistry department, collage of science for woman, university of baghdad, baghdad, iraq 4 ministry of industry and minerals, baghdad, iraq abstract in this work, corrosion parameters were evaluated using potentiodynamic polarization curves. in order to determine corrosion parameters of potential and current density of the interesting metal, carbon steel, environmental conditions of external corrosion of buried carbon steel pipeline in iraqi soil were prepared in the laboratory using simulated prepared conditions. solutions of sodium chloride at different concentrations (300, 1100, 1900, 2700, and 3500 ppm) were used. ph of solution were acidic at ph =5, and alkaline at ph = 9. laboratory conditions were similar to those of iraqi soil where the pipelines were buried. temperature was constant at 20 °c. potentiodynamic polarization curves, of potential vs. log current density, were obtained using m lab multi-channel potentiostat/galvanostat. the carbon steel coupon (astm a179-84a) was used as the studied metal. the results of this work reveal the behavior of carbon steel in external corrosion conditions under iraqi soil. the rate of corrosion, of carbon steel, increases with the increase in chloride concentration in solution. as ph changes from acidic to alkaline medium, the rate of corrosion decreases. key words: corrosion, carbon steel, polarization, potentiodynamic polarization. introduction pipelines play an extremely important role throughout the world as means of transporting gases and oils over long distances from their sources to the ultimate consumers [1]. pipelines are affected by environmental conditions, whether they are buried in soil or sea water or constructed on ground. the major environmental effect on pipelines is corrosion. for buried pipelines, external corrosion, which is resulted by environmental conditions, is affected by: moist, temperature, ph, salts types and concentrations, type of soil conductivity and resistivity, type of pipeline alloy material and concentration of oxygen in soil. the parameters which play the major role in external corrosion of pipelines buried in soil are: moist, ph, temperature and salts, especially chlorides. iraqi journal of chemical and petroleum engineering university of baghdad college of engineering evaluation of sodium chloride and acidity effect on corrosion of buried carbon steel pipeline in iraqi soil 2 ijcpe vol.15 no.1 (march 2014) -available online at: www.iasj.net cost of pipelines failure, caused by corrosion has taken the attention around the world as a great deal of the problem. in a widely – citied study (nace corrosion costs study) by the national association of corrosion engineers, nace, the direct cost of corrosion in the u.s. was estimated to equal $276 billion in 1998, approximately 3.1 % of gross domestic product (gdp). however, this estimation is incomplete and closer examination of the nace data indicates that total corrosion costs in the u.s. now exceed $1 trillion dollars annually. the indirect cost of corrosion is estimated to be at least equal to the direct cost. in that case, the total cost of corrosion is $993 billion in march 2013 and estimated to exceed $1 trillion in june 2013 (based on estimations of gdp) [2]. the corrosion process in buried or partly buried pipelines is due to curried flow from anode to cathode through the ground of ionic conductivity and from cathode to anode through metal by electric conductivity [3]. oxidation process happens at the anode while reduction process happens at the cathode. iron as a carbon steel has been one of the most extensively studied metals in the environment. in neutral conditions, oxide or hydroxide, which forms on the metal surface, provides distinctive layers. these layers have significant structure that tends to be determined by anions present in solution [4]. corrosion kinetics is governed by the reduction of oxygen present in solution. the general reactions that occur are [5]: dissolution of iron as ions at the anode: 2fe 2fe ++ + 4e (anodic) reduction of oxygen at the cathode, where electrons flow from anode to cathode: o2 + 2h2o + 4e 4(oh ) (cathodic) the sum of overall oxidation – reduction reaction would be: 2fe + o2 + 2h2o 2fe + 4(oh ) electrochemical corrosion experiments measure and/ or control potential and current of oxidation/ reduction reactions. several types of experiments are possible by manipulating and measuring these two variables. potentiodyanmic polarization technique is generally used to produce a qualitative picture or “fingerprint” of a substance in a given solution. it also detects important information such as: 1. the potential region over which the specimen remains passive. 2. the corrosion rate in the passive region. 3. the ability of the material to spontaneously passivate in the particular medium [6]. a potentiostat is used for monitoring polarization parameters (potential and current density) [7]. polarization method, using potentiostat, can show the combined effects of different condition on the polarization parameters. conditions of which rate of corrosion of carbon steel is measured of different concentrations of chloride as nacl, different ph and different temperatures levels. each condition has its characteristic and unique effect on the cathodic and anodic reactions. therefore, the aim of this work was to evaluate, the effect of corrosion parameters, chloride concentration, ph and constant temperature on the corrosion rate of a well-known, pipeline metal which is the interesting carbon steel. qasim sulaiman, ali al – taie, dahlia mohamed hassan and commission of research and industrial development -available online at: www.iasj.net ijcpe vol.15 no.1 (march 2014) 3 as the parameters go vary, rate of corrosion was influenced by the three of them at the same time, resulting in a competition between these three parameters, of which one is going to role at particular moment of the reaction. experimental work materials material used in this work is low carbon steel coupons (astm a17984a) [7]. table 1, a nominal and the analytical chemical compositions of carbon steel chemical composition, % a nominal analytical c 0.199 0.191 mn 1.95 1.95 p 0.016 0.014 s 0.018 0.015 cr 0.015 0.015 ni 0.007 0.003 mo 0.008 0.008 v 0.004 0.003 cu 0.024 0.028 fe rem. rem. chemical composition is shown in table 1. flat coupon dimensions were 1cm×1cm. coupons were polished with silicon carbide (sic). then, edges and faces of coupons were grinded using unipol–820 grinding/polishing machine. rotating speed was adjusted in the range of 100 to 400 cycle/second running under tap water. degreasing was produced, by immersion in acetone after whipping with benzene wet cloth. afterward each coupon was preserved in the dessicator to prevent moisture. chemical solutions solution of ph = 5 and 9 were prepared using hcl and naoh. stoke solutions of each hcl and naoh of 1 m were prepared. then solutions of 0.01 of each hcl and naoh solution were prepared from the stoke solutions. solution of ph 5 and 9 were prepared from the later, 0.01 m, where the increase in na + and cl were accounted to be negligible [8]. concentration of chlorides, represented by nacl, were chosen according to their presence in iraqi soil after analyzing chloride concentrations in laboratory. soil samples were taken from different locations in iraqi. concentrations of chlorides in samples were measured using titration with silver nitrate. potassium chromate was used as an indicator. results were ranged from 300 to 3500 ppm (in average). ph values of samples were ranged from 5 to 9 (in average). total dissolved solids (tds) and conductivity were measured for the solution samples using (reed yk-22ct conductivity/ tds meter). temperature of all solutions was maintained to 20 ° c. electrochemical corrosion tests electrochemical polarization experiments were carried out using a potentiostat, m lab multi-channel potentiostat/galvanostat. graphite carbon rod was used as an auxiliary or counter electrode. all potentials were measured against a saturated calomel electrode. the measurements were carried out in a three electrode cell using a computer assisted potentiostat. a thermo stirrer was used to set the required temperature (20 °c) and to achieve temperature homogenization. open circuit potential test after preparation of cell solution and electrodes, the free corrosion potential was measured with respect to saturated calomel (sce) with time using digital ammeter. the exposure area of the working electrode (carbon steel coupon) must be 1cm 2 to obtain the correct value of the free corrosion evaluation of sodium chloride and acidity effect on corrosion of buried carbon steel pipeline in iraqi soil 4 ijcpe vol.15 no.1 (march 2014) -available online at: www.iasj.net potential of the coupon at each measurement. corrosion potential value was recorded till it reaches a steady state value. it takes about 30 minutes for the steady state to develop. potentiodynamic polarization tests potentiodynamic tests were carried out after preparation of salt solutions. these later are chloride concentrations (as nacl) of 300, 1100, 1900, 2700, and 3500 ppm. each prepared with ph 5 and 9 where temperature was set at 20 0 c. these solution parameters were based on the tests of iraqi soil which were taken from different places in iraq, from the north to the south. fig. 1, a simple sketch of polarization circuits the potentiodynamic polarization cell circuit as shown in figure 1 was set in position to start the potentiodynamic polarization to plot behavior of carbon steel coupon at the studied solutions of different chloride concentration at different ph values where temperature is constant. by applying the potential from potentiostat and at each setting, the potential applied and the current were recorded using m lab software of the computerized potentiostat. for more accuracy, time step between each recorded points was set to 500m.sec. the potentiodynamic polarization curves were recorded by a constant sweep rate of 2.0 mv/sec. m lab multi-channel potentiostat/galvanostat gives automatic results of corrosion (icorr), anodic and cathodic slopes (ba, bc respectively), weight loss (gmd) and penetration loss (mmy), curve of potential vs log rate of corrosion were obtained from potentiostat results. the value of cathodic tafel slope (bc) is neglected in the table due to its large value as a result of almost vertical cathodic curve, mentioning that it is large but not infinite. results and discussion potentiodynimaic curve plotted between potential and log current density. each curve shows the behaviour of carbon steel at different conditions of chloride concentration, which represented by nacl and different ph, acidic and alkaline medium. fig. 2, potentiodynamic polarization curve of carbon steel in solution of 300 ppm concentration of nacl and ph= 5 at 20 °c fig. 3, potentiodynamic polarization curve of carbon steel in solution of 1100 ppm concentration of nacl and ph= 5 at 20 °c qasim sulaiman, ali al – taie, dahlia mohamed hassan and commission of research and industrial development -available online at: www.iasj.net ijcpe vol.15 no.1 (march 2014) 5 fig. 4, potentiodynamic polarization curve of carbon steel in solution of 1900 ppm concentration of nacl and ph= 5 at 20 °c fig. 5, potentiodynamic polarization curve of carbon steel in solution of 2700 ppm concentration of nacl and ph= 5 at 20 °c fig. 6, potentiodynamic polarization curve of carbon steel in solution of 3500 ppm concentration of nacl and ph= 5 at 20 °c fig. 7, potentiodynamic polarization curve of carbon steel in solution of 300 ppm concentration of nacl and ph= 9 at 20 °c fig. 8, potentiodynamic polarization curve of carbon steel in solution of 1100 ppm concentration of nacl and ph= 9 at 20 °c fig. 9, potentiodynamic polarization curve of carbon steel in solution of 1900 ppm concentration of nacl and ph= 9 at 20 °c fig. 10, potentiodynamic polarization curve of carbon steel in solution of 2700 ppm concentration of nacl and ph= 9 at 20 °c fig. 11, potentiodynamic polarization curve of carbon steel in solution of 3500 ppm concentration of nacl and ph= 9 at 20 °c evaluation of sodium chloride and acidity effect on corrosion of buried carbon steel pipeline in iraqi soil 6 ijcpe vol.15 no.1 (march 2014) -available online at: www.iasj.net from figures 2, 3, 4, 5, and 6, it is shown that the corrosion is heading towards the negative potential while chloride ion concentration increases in solution. the same behavior is shown in case of figures 7, 8, 9, 10, and 11. since oxygen depolarization controls the rate of corrosion through the sodium chloride concentration range, it is of some interest to understand why the rate increases. the rise of corrosion rate appears to be related to a change in protective nature of the diffusion barrier rust film that forms on corroding iron. in distilled water having low conductivity, anodes and cathodes must be located relatively near each other. in sodium chloride solutions, on the other hand, the conductivity is greater, hence additional anodes and cathodes can operate much farther removed one from the other. at such cathodes, naoh does not react immediately with fe(oh)2 formed at anodes; instead these substances diffuse into the solution and react to form fe(oh)2 away from the metal surface. obviously, any fe(oh)2 so formed does not provide a protective barrier layer on the metal surface. hence iron corrodes more rapidly in dilute sodium chloride because move dissolved oxygen can reach cathodic areas. [9] comparing figure 2 with figure 7, it is shown that with ph change from acidic to alkaline medium, the corrosion rate decreases and corrosion is heading towards less negative potentials, the same is noticed in the cases of figures 3 and 8, 4 and 9, 5 and 10, 6 and 11. potentiodynamic polarization result of current density and potential of corrosion processes, which were taken places in this work are presented in table 2. table 2, potantiodynamic polarization results ph cl ppm ecorr -mv icorr ma/cm 2 ba gmd mmy tds conductivity ms 5 300 512 0.0407 266 10.175 219.78 417 0.635 1100 530 0.0443 190 11.075 239.22 1467 2.29 1900 607 0.0482 200 12.05 260.28 2573 3.97 2700 590 0.0513 300 12.83 277.12 3580 5.2 3500 650 0.0548 250 13.7 295.92 4640 6.63 9 300 498 0.0189 130 4.775 102.06 412 0.618 1100 517 0.0248 276 6.2 133.92 1473 2.28 1900 492 0.0305 285 7.625 164.7 2500 3.65 2700 483 0.0333 279 8.325 179.82 3653 5.43 3500 477 0.0334 274 8.85 191.16 4700 6.91 fig. 12, the relationship between concentration of chloride, as a function of corrosion rate and the conductivity of solution in figure 12 it’s obvious that the increase in chloride concentrations, as a function of increasing rate of corrosion, effects on the conductivity of solution to be increased as the concentration of chloride increases. the way of corrosion rate to increase, when conductivity increases, in acidic medium ph = 5, is more obvious to notice than the way in alkaline medium ph =9. at the applied anodic potential, ferrous ions are produced at the metal/passive 2 qasim sulaiman, ali al – taie, dahlia mohamed hassan and commission of research and industrial development -available online at: www.iasj.net ijcpe vol.15 no.1 (march 2014) 7 oxide interface. these are migrated through passive film to the oxidesolution interface and forms ferrous hydroxide. the applied anodic potential stimulates the migration of the chloride ion preferably to the defect sites of the surface. sufficient accumulation of cl in these defects leads pitting. with increase of bulk chloride ion concentration, the potential shifts toward more negative value undermining the role of anodic potential [10]. thus, either applied anodic potential or increased concentration of chloride ion is necessary to increase corrosion process. it is convenient to state that the breakdown of passive film is the start of corrosion process. the increase in cl – ion concentration generally enhances the passivation current density which is a criterion of anodic dissolution of the metal in passive state. these findings could be attributed to weakness and thinning of the passive film as a result of adsorption of cl – ions on the oxide surface. the adsorbed cl – ions tend to enhance the dissolution of the oxide film. after the incubation time, when a certain critical potential is reached, the passive current density begins to rise suddenly, indicating passivity breakdown and initiation of pitting attack [11]. in ph range from 5 to 10, corrosion current quickly decreases; in such stable region, the oxygen diffusion rate through the passive film was likely to be lower than the corrosion reaction rate [12]. in a broad range of about ph 5 to 9, the corrosion rate can be expressed simply in terms of the amount of oh present (e.g., µm/y per ml. oh per liter of water). at about ph 4.5, acid corrosion is initiated, overwhelming the oxygen control. at about ph 9.5 and above, deposition of insoluble ferric hydroxide tends to stifle the corrosion attack. it is worth mentioning that the corrosion potentials of carbon steel were not dependent on the cation type (na + ) [13]. conclusion the conclusion from the research work which has been presented is as follows: 1. concentration of chloride ions has the major effect on corrosion rate. when chloride concentration increases, corrosion rate increases. 2. corrosion rates are increased at acidic medium more than in alkaline medium. 3. oxygen solubility affects the rate of corrosion at solution of sodium chloride concentrations. the more diluted the solution would be move oxygen can reach cathodic areas, causing more corrosion in the metal surface. refrences 1dr. maher a. alodan, dr. faraj abdolaleem, (2007), “pipeline corrosion in soil”, journal of king saud university engineering sciences, no. 425/17, p6. 2gerhardus h. koch, michiel p.h. brongers, and neil g. thompson, y. paul virmani, j.h. payer, (2013), “corrosion costs and preventive strategies in the united states”, publication no. fhwa-rd-01-156. 3dr. jafer t. al-haidary, dr. mohammed h. hafiz, yasir m. a. al-sahib, (2011), “galvanic cathodic protection evaluation of a steel pipe in iraqi soil”, eng. and tech. journal, vol.29, no.9. 4luis cáceres , tomás vargas, leandro herrera, (2009), “influence of pitting and iron oxide formation during corrosion of carbon steel in unbuffered nacl solutions”, corrosion science, http://www.sciencedirect.com/science/article/pii/s0010938x09000845 http://www.sciencedirect.com/science/article/pii/s0010938x09000845 http://www.sciencedirect.com/science/article/pii/s0010938x09000845 http://www.sciencedirect.com/science/article/pii/s0010938x09000845 http://www.sciencedirect.com/science/journal/0010938x evaluation of sodium chloride and acidity effect on corrosion of buried carbon steel pipeline in iraqi soil 8 ijcpe vol.15 no.1 (march 2014) -available online at: www.iasj.net vol.51, issue 5, may 2009, pages 971-978. 5m. fontana, (2005), “corrosion engineering”, taha mcgraw-hell publishing company limited, 3rd edition. 6david g. enos, louie l. scribner, (1997), “the potentiodynamic polarization scan”, solartron analytical, technical report 33, issue 2.0 – january 1997. 7dr. sami a. ajeel, ghalib a. ali, (2008), “ variable conditions effect on polarization parameters of impressed current cathodic protection of low carbon steel pipes”, eng.and tech, vol.26, no.6, 2008. 8miyata y.; asakura s., (2002), “ oxygen reduction reaction at rust free iron surface in neutral unbuffered chloride solutions”, corrosion science, volume 44, number 3, march 2002 , pp. 589-602(14). 9h. uhlig, (1985), “corrosion and corrosion control”, john wiley and sons, third edition. 10md. asaduzzaman, chand mohammad, mustafa, mayeedul islam, (2011), “ effects of concentration of sodium chloride solution on the pitting corrosion behavior of aisi-304l austenitic stainless steel”, association of the chemical engineers of serbia ache, 17 (4) 477−483 (2011). 11aljana petek, valter dole~ek, (2007), “localized dissolution kinetics of low carbon steel”, acta chim. slov., 54, 725–729. 12h. kim, c. paik, w. cho, b. cho, k. yun, y. kim, j. ju, j. kim, m. kang, j. ha, k. kim, (1997), “ effect of dissolved oxygen and hydrogen ion on corrosion rate and passivation of carbon steel boiler tube”, journal of ind. and eng. chemistry, vol.3, no.1, march 1997, 51-55. 13ogundele, g. i., (1989), “the effect of cation on the corrosion of carbon and stainless steels in differing chloride environments”, corrosion, vol.45, no.12, 981-984. http://www.sciencedirect.com/science/journal/0010938x/51/5 http://www.ingentaconnect.com/content/els/0010938x;jsessionid=13s7ojmufjl8n.alice i i iigpi ! d 1 1 n o 4 { d d e m b s 1 0 1 0 ) 4 7 5 7 e'xcess volumes of heavyoilstocks mixtures + (kerosene or xylene) at3o3 ( haidr m ar aamarc ch.n ical engi.e*ii s depadmenr.collaeeofeigireenng,nsnain lrn ve6i! baghdad l'aq binaq nirturesofrhree, heaq oil-$ocks had been subj'cred to deisiry mersemena the d a e h a d b e e ; . c q u i e d o n i h e v o h m e n i c b c h o v i o r o l r h e s e s v s l e m s t h o h e a v v o i l $ ' c k s u $ d w e r e of good vlrity, n;mely'10 stock.60 srock, and 150 slock 40 siock is $e lighre$ one *ith'apl s,;it] 33.7;hib 60 st."k is middle qpe and 150 $ock is heavvone *ilh "apl gmvitv2?7 afd i3.s resp€dively srocks *ith kerosctre o' xvlbnd rbrm non ideal mirt'rcs' for *hich etccs volume;an be posirive o. negative mixlures ofheavv oilsrocks wilh parafinic soike (keroscne) shob negarile ;rc*s volume. while, aronatic rinss rcstrlls a lower posirive exce$ volume as shown i;xybde when bledding wnh 40 stock and 60 stocl br( a negdrivc excess vohrme *hen blending with 150 stock the gruvirv ofoil-$ocks has an efle'r 'i exce$ voludre shen the or! stocks;piked with kemsenc or xrlene those,40 $ock !srvpical lighr rype resuhed in minmum negdiv;exd$ volumeof_21s, qhen ir was lpikcd rvith rhc kercsene while the spikedhe'vvo'l * o _ c * w i r t , l c o s e r e g a v e a * i n u m e x c e $ v o l u m e d f l l 2 ' f h c r e d l i c h k i s t e r e q u r i o d w d s used ro nr r]t exces volume vallles, ard rhecoetlicients aid e$imate olne nandatd eror lalues key*ords: e:ce$ volufre, mixingbehuior, td ofmixinc introduct'ion thc mixing ol difercnl dompounds gives rhc to sol0tions thar generallv do n't behave idcally thc devialion fiom idealirv is exnrescd by mmy thermodyradic p'openiespanicula.ly aclirirv coclncienb and exce* or residual popenies [l]. erc($ fiennodlnamic propcfies are useful in ihe $ud) ol molecular interactions und amneencnis [2]. in poniculf. thev reflect tle intemclions rhd take place betwecn so!ure tu vatu-"'aj heaq ott solute. solute solvetrt, and solvenr sd!vcnr species []1.ii seneral, posilive cxcc$ volumes may be due to compensarion betw*n strong like inienclions guch as th.se prcsenl in alehols) and equally unlike h-bond inreractio.s (such as lho* presni between alcohol rnd dhs) [],41. ncsative cxce$ v.lume will occur when thc unhke inlerutions prevlil oler selfasociation ll,3l. binary mixlures m an ,mponanr crds ofsolvcnts and solutions, snj the behari.r ol rhen p[ysical propeilies is nill unclear [s] j. rhe blending ol penoleun com0onents halins dillerent physical popcrties, exces vollrmes occu. becduse lhe mmponenh do nor lrm idcal soldrions ln an ideal soluton, the toul solulion volume is eqdal to the sum ol the lolumes oflhe componetrts l. oiler lor r $lurion ro approach idealitv, the n,olectrlcs of the matoiah blended tqethcr rnl$ be simil$ in sizc, shape. and propetiss ,f thc nature of $c compnenls diffen atpftciably, then dcviation ftom ideal bchavior day be cxpected. thh devirlon nay be eitherp.sirive or negdrivq lhar is. rhe total volume may incrersc or decrease q[en de componenls arc blendcd [3] theblending of oil e.cks results in volume chatges, caused by rhc notr-ideal behlvior of oil systems as compared wirh thc calculated idell volume. sinca thc oil indust! uses volune meosurcdrent in its balan.cs, ihe apparent dhcepancies in marerid fray cius financial compliciiionswhich in so'ne cas.s hove rcd thc e\ces rolume behavior ol healt oil_ nocks mixtures is inporbnt. since only small amo! ofdalabase tr€s publhhcd, especiallv on minurcs of hedly oilslocks nith puf hldbcrbons. while little eudiss were published on mixtures of difterent tl'*s ol a lull unde*landing of iherdodyilmic an'l knspon pr.pcnies of bin.ry liquid slicms k e$ential in many chcmical engineering pro.o$cs such s desis! calouhtion, heat nansfer, mas tansfdr. nuid flo*. rnd so tirnh l7l we havc slarted n rcsearch progdn of the ercess propenies of nixtu.es conraining (hcavy oilstocks + spiket. ln this no* $c have rep.hed cxperimenr.l data such as dersiq over the whole nisc of composition the pesentrvolk was in ve{ig.rcd lo evalllnlc rhe lolumenic behavior of blends ol the he.vroilslocks. fu hereim.f rhe workrvas ro investigare rhe eifecr ol hydrccarbons spikes such as kerosens and rylen€ od the exes volume of these mixtures. three heal} oil sidcks $erc obralnc,l lnm al dunr rclinery, namelt 40 slock, 60 siock, and 150 $ek. 40 (ock is the lighrcst one rvid i,^pi sevii] il.69r'hile 60 nock is middle rype and 150 srock is hearl one. wrtrr "apl grvny 27.74 dd 23.79 respectvely the main propenics oloil nocks (10 stock, 60 stock, lnd 150 stock) were measured in al_ ddra rcllnery labostories accordine to afl and astm sdecilic.rion, as listed inlable l. rcpe!or.t1 n04 1o&ember r0t0) siopper widr a surfacht cleani4 fluid (gasoline), lhen witn acctone and dried ensuing rh.r au renoved by drying wiln a curcnt hol air pa$ing slowl] rhrough the pyknometer and sropper capillary. wiping lhe ou$ide ol pyknomelor and stopper with a olean, lint-lree cbln. nomally pyknomeler oleaed b, using (ga$line and a@lone), ond died. all thc density medurencnts were caried od at results and discussion the excest rhcmodynamic propen'es suoh as excess volumes olmixtures of hetvy oi lstocks lre coi sidenble i ntercst in lhe fi eld of tmnsp.rlation. usually lighr oil-slock blended wilh dediufr dd ako wi$ heavy oilsrdck to sath8 such specificdion lbr lubiicatina oil and anoder uses. although lhese trslmenl have led to considefble insicht inlo themodrn.mi. behavior ofrhesc mixtures. but lhcse blending led mostly lo kerosene w6 uscd as pelrcleum fiaclio. io nudy the erces lolune phenomem of hearl oil srocks. this lmction was supplied by aldufr refincry, while lhe xylenc w6 supplied tom merck company, gemdy. the neihod olmilng proces *as tchieved b) electidrl nircr al room lerlpedtdre (2025 "c), densn, measuremenls sas made immediotely, after prepaing lhe mixtures ro avoid deposir f.rnarion or uporizing lhe lighr ends. all densily canied out dt ahospherio presurc. the following mixlures *ere prepaed in rhis three heavy oil-stooks binary mixlurs oler a mnge of weisht peeenr (0-100) al tenpedue 30'c. binary nixrlres of heovy oil stocks with spikes {keosene + xylene). over a raige of rcighl percent (0-100) at densiry deleminalion of heavy oil-docks, spikes and their blends were canied outusng pyknometer having a size of 50 cmr a@ording to the sland ard methods (ip i 9 l]) r3). the pyknometer w.s placed in a *arer bath rype (.,ulabo f25) as show! in fig. i which was capable of mainuining the teoperalurc wi$in + 0.1 !c ofthe selecled temperarurc. thoouehly cleanins the pyknometer and i u.*vo u no.{d4enbq20r0) table 2: exce$ voluneofbinery synefrs: or si@k ,10 wilh slook 60 table 3i exce$ voluheofbinar] sr$cmsi.f stock'10 wilh sloek 150 the heavy oil-slocks used *ere ol good varity, namely 40 $ock, 60 $ock, and 150 nock. 40 $ock is the lighrest one *hh 'api grivitt 33.7 *hile 60 $ock is middle tvpe and l5o nock is heovy onc. with 'api cnvirv 27.7 and 23.3 respectivcly. thre binary mixrures of heavy oil stocks have bcer made. thc volumetic behaviot of thc binary mirtures of heavy oilnocks *i$ dilleent densities volume *as calculatcd by rhe linear expre$i.n in tems of ma$ fraclion ol blendins componenr as tbllo*s [9] p ! + , . t p l p 9 | a i p i excss volume isdenned by the c'iualron: where /'s is lhe actu.l speoific volume. which is equal to l/pi" in cnr/kc lnd l.* g rhs measurcd densny ir *sr',,r' exce$ volunes lor binary heavl oil-stooks nixrltusare sumdarized in rables 2,3 and4 lfrhe dala in the fom ol erce$ volumes ae plofted again$ nas liacrion of refsrence compodenls, snooth cudes arc obrained as shoqn in igure 2 the cudes p!$ rhrougi zerc !r 0 wt% and 100 wt% reference cdnponent, whilc rhe m.ximum exce$ volume occur at, or closc to, mds iaclion ol 0.5. indicarjng thar vt at lhis point should b€ good indicalorofrhc molecular inleeotions rn v ^ , ' excss volune are positive ror gtock a0 + srock 60), and gtock 60 + sock ls0) mixrrres over lhe mas lnction dnge, as sho*n in fig 2 . as onc can se ftom fig. 2lhe doived vllues af v! lor fie nock,10 + siock 150 mixlures ar very hieh (mdimallalue krboutt4.752 rce vor ! no.4 (d{enber2010) cmr/ks ) and neeative over lhe qhole cornposilion range. v" ouryes are alnosl symnelrio *ilh rhe mdidun at 0.5 ma$ lracrio.s. thn negarils sx€$ volume (shrinka8e) cone frcn the chmses in self asecistion (inte! or intramoleoulat and physical inlemotion (van der wals intenction and dipol+<tipole inlenction) belw*n like holecules de€ase the volume ll0l. on tne orher h.nd, ftec lolume efib.ls, intentitial accomnodation or inlerutions benven unlike molecules oontribute lo also gives erce$ volume gtnk 60 +stock i50) mixtue due lo lhe dilierenl in lhe chemifl enposilion and slructure bonds between the molecules, in addition ro rhe difierence id specific g6vit, be.een lhcse the lhee heavy oilslocks were, also, blended with kerosene md xylene. the spiked heavy oil-stock hove ben subjected to densily elalusle lhe volumetic behavior of the* sysrems. the densiry dab obtained far each hcaw oil-$mks/spike pans de rcponed in the lom ofexcss volume ve at a given m6s tlclion of spike x: as sho*n table 5: excs duns v!. lor spiked emk a0 t,ble 6 e\ces volumes v', lor spiked fig. 2 excess volune ve roi binary mixlues of srocks oil the small volu6ofthe ve is rhe esult oflhe idealiry oflhe stdk 60 + stock 150 mixlure, i.e. ihe differene baween the mixlure volume vni and tne ideal mixtue molar volume vild = xvr + (l x)vr is very small (naimum value ofab.ut0.94cm'ag. bui ir 7 ere$ volume! v', for spiled rcpevor.! no.4 ldcmbs r0l0l ll lhe dala in lhe lom ol speoific cxce$ volume are phned asainsl ma$ fraction spike, shooth cunes arc obgined as sho*n n figs. 3 and 4. the curyes pass lhroush aro ar 0 ri% spike and i00 *r% spikes, while thc maxinum exce$ volume occur at, orcloeto, mass freion of0.5, indicatinglhst vs ,t t[is point should be sood indicalor ol the inrdactions in $esc systems. ir h gener.lly ob$ cd drar thc addition of middle penoleum lections, s0ch $ kemsene to lhe lhree h*q oilnocks of dircrenl dersities produces negative exce$ volumesl ir othe. nords th nkagc cllculated ideal volume, as shown in tables 5, this shrinkage efiect is direcily propodionll wiih sdecific sravily oarhe oil-slocks, so lrrat when rhe dcnsity of oil-stock incrcas the negarivc cxce$ volunc will incrcase asonccan see ftum fig.i the derived vtlues of vt ror the (kerosene + haq oil_nockt mlxtures .e very high (msxinal valu€ s about g1l2o2 omr/kg) and nesdivcorerrhc whole composilion mnge. h sems ihar rhe posirion.fpaffinic smighl chains has greal etfdcr on lhe volumctric behalior of these mirtles. 1 he n-palmns behlvior rs consisiert wiih a close'packed snucturc, rhe mi{urc having . more tishtly packed strucrurc than conponent liquids. these obscrvations c.n be directly related to the e\ishnce ol long oric.ralional order in the negarive vf aries due to dominonoe of lhe rollorving fetoa i i u: (d) chemical intcaclion between oonstilueni molecules such as helero_nolecular a$ocirlion thrcueh rhe fomation ofh_bord, dften termed s stong specific inremction. (b) a$ociation thrcugh seaker phlsical lorces such a didolr forcc or any other forces (c) accommodation of moleculcs of oio c.frpone intothe inrcntilial posirionsolthe nnctual neiwork of molecules ofthe olher (d) gcomelry of the molecurar shdcrure that lavoe fiting of rhe comp.nent molecu:* the binary mirtures of slock .10 ,nd stock 60 ri$ xylene shot positive values of exces volume, and lhus erhibit expansion, as shorn in fig. 4. this eltcct is appreciablc rellte ro rhe lecl, rhar such compounds are '.slruclure breaking materieh leadins lo positive cxcess fig. i exce$ volume ve lor binary mixtues ofstock oil&emscnc rcm vor.11 ro.4 (os€mb*2010) thc factob thg1 ae mtitly responsible for the volume expdsion i.e.. positive values of vt, (a) dnruplion orone or both @mponenb d ! solution srslen. a suibble ehmple of thh, lne rupiure of h-bonding of one oonpoud by the olher, o! breaki.s up of eciales held losether by {eater physical for@s such as dipole or dipole-induced dipole int mcl ions or by any other lan der lvsh forces. slerio hindrance. tle ve lalues for lhis sysrem e most nesarive i l4]. (b) the eeomell of moleouhr dnctur€ which does not rrvor nnins orthc mol{ul€s i ,t (c) steic hinddnce which opposs the proximiry of the constitre.tmolsules. the binary nixlurc of slook 150 wi$ xylene shov negative values of ex€s volune over the whole@mposnion @ge as shown in n3 4. ve cudes arc almosr symbelrio vilh the ndinum al0.5 mas fmctions. thk ncgalile exces rolum€ ghrinkase) co-me rron the chanses in *lr-dsniation (inhr or innamoleculst and physical intetrtion benven ullike noleoules increase lhe volume ll0l, the inlrcduotion or no metyl 8rcups in xtlene, should cause nrnher enhancement ol thes altracrile intemotions and il should 6lnher yield 6oe necative values of ve. however, it is nol obseryed expcdnenlally. ll day bs due to the presenoe of sgric hindrance bencn the two nelhyl coups of xylere dd rhe oomplex $ruolure (n-paiaffnic sluctu€) ol sleh l50, which iestrict the prop€r oienladon of thee molecules torad lhe ling rhus m*ing i.temclions serler. among lhe xylene u sybmelrical noleculc, thls it ofen ledl ": ,;-." _ ", fig. 4 erces volume vd lof binary mixtures ofslock oilr(ylene fie wllkno{n rcdlich-kister polynomial equatio.u5l, which hs the following form v e = x , * . l i = o a t q , * ' ) t . . . r t t is used to conelote the experimental data. the c@flicienl ai is det€mined by a multiple regre$ion dalysis based on rhc l4sl{qums method and is summolized dlodg with the sbndard devidrions benveen the dperimenhl and fitcd valucs of lhe cdrespondng a computer pmgram was used b nnd the values of $e conslants al, a! ar aa snd aj that give the be$ fining of lhc expelimenbl dah. ne ccffcienls ror @h system i c , lor eeb hixture ae lbulated in loble 8, , " 1 . . f rcpevorll no.lldkenber2oro) the qlus or rhc .o6bnrs a, ar ar' a anll a, {h*e g've the be( fining ot tne experimenbl dara for e&h pipe diamerer' werc cobputed by slatistica pognn 'fhe vatues of s|lndad entr (sd) [14] hcseen thc calculttei sd expenmenbr datun poinb are obtained usins lhc equatidn . . , . . . ^ . d ^ ^ 1 : . | o l r ' " ' 2 . r " ' r ! : ! : : i i 1 ) p aftinic hydscarbon (keosens) wi$ heaq oil-stgks pbducss negativc ex€$ valude' while lhe blends of afnatics hvdr@adons lxvlenc) wih heavv oilsrocks producc pcitive erces rctrme exept stok tso so rhat this blends producc neaativc exce$ volune due lo composition o i stock _ i 50 w'th hisn @marics slruclurc' thes binary dala w;r coftlatd q.ll nith ihe redlich-khter nomf,nclaturx ai: coefficienc of redlioh_kisret p'rvnofr'al n: tobl nunber of experimenlal varues v!: ex*s volume. cnl/ke x, : sss fraclion ol component 2 p-, : ddsiy of fte mixtute for bimry p : deisty olconponent i, g/cr'r r(r."'., j:t,) /i tei h ire calculatd ralue dd r"1, is the expennenial value conclusions lfs genenlly obseded that the blending of lrch and medum o'l$ocks snh heavv o'r_ (ml,reslhs in volume lo$el! cau$d bv rr' non-ideal behavior of lh$ systrm !5 cohpafd wilh $e calculaled idal rolume ak it! obsrved that fte mx'ng oi rcpevo.11 no 4(decenbd,010) 'iable 3: cocmcie.ls ofrhe redlich-kisrer equalion aiand srandard deviarion for ve reierinces illanalendu pal ond rekia gaba. densiriei exoess mo l$ volumes, speeds of sound and isothemal $nprcsibifties lbr {2-(2-hexylorrethoxy) ethlnol + n, alkdou systens at rempcntu4 between (283.15 and 303.15) k", l. chem. themonlmnics 40 (2003) 7t0 758. [2]1.m. abdulagarov, f.sh. aliyev. m.a, talibo!. j.t. safarov, a.n. shahvediyev and e.p. hrssel, "high pre$ure densities and deriled v.lumenic poperties (exces and panirl nolar voiumes, vapots pressuret of binary melhanol + c$anol nixtures ", themochimica acto 476 (2003) 5r-62. [3]se-jin ln dd so jin park, exce$ mold volunes and rer6ctive indices ot 293.15 k for lhe binary and tenary mixiures ol diisopmpyl erher + erhanol+ 2,2.4-lrimcthylpenbne', jounal of indusldal and engineerirg chenistry l4 (2003) 377 331. [4]d. sen. m.c. kih, " exces nolar volumes and cx€$ molar enihllpies of binrry dixtures lor i,2-dichloroprcpane + 2-alkoxlelhanoi acelates ar 293.15k', thermochifticaaora 471 (2003) 20-25. [s]p.n. sibiya and n. de€nadayalu. ''excess nolar volumes and ienlmpic conpre$ibility of binary syscms {lri@rylmethylsmmoniun bk(tinuorcmethysulfonyl)imide metha.ol or elhanol or l-propdoll at dife€nl lempeftures . j. chem. themodynam ics 40 (2003) i04l 10,15. [6]thuf n. a., consction of exce$ volune of oil stocks , m.sc rhesis, nahrain univenity, baghdad, imq, 2004. [7]jalal basiri pana and mahdieh farchbafhaghro, ' excess molar volunc and viscosiry deviation lor binary mirtures of polyelhylene glycol dimcthyl elhft 2s0 with l,2-alksediols (c3{6) l c e v o r l r n o 4 l d { e m s r r 0 r 0 l ai r'= (293.15 ro 3ll 15) k , j chem. thcrmodlnanics rl0 (2003) 732 783 t3l sbndard melhods lor ^nalvsis aid tc$ing ol pdrolcum add relaled produc6 , wilcyj..rndsods, nos yor! tglasho'oft, s.j, booker d r an'l tunrd lc.r.. volumetic behavior 01 oi! mixrutes of crude oih and lighr lll&ocarbon'. journa! of the innilute ol energy , vol.65. septenber p lll 116 !ojan zielkienicz, excc$ vo!dnes ol mlrid! in cn,n dimcrhylaccradide + dcrhatrol + rv.tt add (n,n dimedrylacetamidc + erhanol + *.tet al r rcmpenturc 313.15 k, j clren thcnnod!damics 40 (2003) 43l .1r6 lllim.m.h bhuild atrd m h. llddin, erse$ nolar volumes and erce$ viscosirids for mixtutos of n,n dinethtlibnnanide rvith mcrhanol, e(unol ond 2-prc|]lnol ai diilrent rempebtures , j.unal of molecular liquids ll3 (2003) 139 la6 [12],^see ,^. jabd a rrak. composirion and tcmpemrurc dcp.nden.c ol lhc excess volrfrc ot oil stock mixtures', m sc thcsis. nahraid ljnivc6ity, b.ghd!d, lrdq, 2001 tlrlshymaa k a., eiiect of thd chemical composilion .n r.rccs v.lumo ol mixtues with petolcum fracrionj, ms. thcsis, nalmin unileeiry. babhdaj, iraq, 2005 tl4lsanjccv maken. atrkur gar, nrvced vema, k c. singh, seungdoon l-ecand lin w.n park. molarexc.$ volllmeor b ll acebtc with cycloherdne .. abnatic hydrocarbons at 293.15 k, j. !nd. eng chen.. vol 11, no. 7, (100r) tl5iyang tianyu, xta shtrqian, dl zhiguo aid ma penheng, derst, add exccs mdlar vdhme of airrry mixtures of p-xylenc+acetic acid and o' x)lene+acetic acid at diffcreni temcerarurcs and pre$ures , chiicse rournrl of chehical ensincerirg, l6(2) 247-255 (2003) (pt vo rr no ltde@n6q:0|0) jrljj .$ 4llvl i jlr |+.lr or (dr!rr+o!-.!1 !i,l) it}rsr4! a!jl-.li *ir j|r lt-ir vljl -j r+ j" gli l|j 40 .4jl-!l elr illjrll +t illl .r trjjr tr)j .rlir f s l+i .!jr 3! l:rrrl:i]jrr qjji rlli !.r, ur c-+jr dll.jr ;j! t 50 jf jl 6j+ ujr li,'r r 60 llfy if i riir ; alj jr rrr, jj.l .r iilr ar i+ .rlrijlr !e+jr-q & irlrkir:{rl dlj ii: a!!r ijlr !r ri,:5 rj)iri!$r; o+ $ ri tl-<rjr4r, i su)r ,!! jr ir q:4111rl is' !!.1 ;j!:l !.i! r.ilj ; rror jil.3j ij! j e.! (!b_)rri,i) *+lri$ e.!ur :ii ij!)r3,91 ;j|;r rr ,:+ l5o .4rlyi!)r reu .llrjl ,i! r jr ,r+ (l!,lji) slj)lr .ill ni l-'rlsir]lcl rlj,"ll jji strjy r_ r,li jr e-r i-l trts i+ jl 3rl; +-,lrr \-l3l j s+ l)jr !:ll: jr .jrljjl -r1.j !l,.l50rrfyij !b)r-tijl ilurs i1.2 glr rjl rijiu i!gl'rql ji--jrf.150 .4! etji .. r5 }< ljirr l.r!11 ertrl s!!rr j!43 +r risr4 jjjr (pevol! no..ldrcmbsr01o iraqi journal of chemical and petroleum engineering vol.16 no.2 (june 2015) 5356 issn: 1997-4884 single well coning problem and applicable solutions raad mohammed jawad. alkhalissi department of petroleum technology/university of technology baghdad-iraq abstract one of the most important and common problems in petroleum engineering; reservoir, and production engineering is coning; either water or gas coning. almost 75% of the drilled wells worldwide contains this problem, and in iraq water coning problem is much wider than the gas coning problem thus in this paper we try to clarify most of the reasons causing water coning and some of applicable solutions to avoid it using the simulation program (cmg builder) to build a single well model considering an iraqi well in north of iraq black oil field with a bottom water drive, coning was decreased by 57% by dividing into sub-layers (8) layers rather than (4) layers, also it was decreased (coning) by 45% when perforation numbers and positions was changed. key word: well coning, iraqi well introduction in simulation many problems can occur according to data and information user apply and water coning is the most common after a period of production. it is usually noted by the water oil ratio, respectively the gas coning is noted by the gas oil ratio in certain wells. usually to avoid this problem in the oil fields or areas which are predicted to be a coning areas is to use directional drilling in the area or by valve controlling on the well-head, but sometimes it is impossible to predict that or there are some reasons like well depletion which happens after many years of production; in these cases other techniques should be used. water coning usually happens in oil fields with bottom water drive and it may affects the oil production economics due to water treatment and disposal issues [1] builder of cmg software is one of the most useful programs in analyzing this problem by simulation and it is used widely to predict and solve many reservoir and production problems like the problem we about to discuss. theoretical background (effect of simple coning) remember that all the formulas of the critical rate represent, as close experimental coefficient, the equilibrium between viscosity forces and gravity forces which characterize a cone. [2] in the mobile face, ∆p between exterior limit and the well, in radial circular flow [2] ∆p= b.q.μ ln (r/r) … (1) iraqi journal of chemical and petroleum engineering university of baghdad college of engineering single well coning problem and applicable solutions 54 ijcpe vol.16 no.2 (june 2015) -available online at: www.iasj.net in the immobile phase ∆p between the two limits ∆p= ∆ρ.g.hc … (2) the pressure is the same for the two phases along the interface, and combining eqts.(1) and (2) we obtain: … (3) certain authors like meyer and shulga [3] have deliberately ignored real causes of instability of cone near the well. they supposed that the critical height is equal to the free height below perforations: with: hc= ht-hp … (4) equation (3), become: … (5) using above formula gives results 2 to 3 times below the reality. other authors like sobocinsky and bournazzel [3] used above formula and added a numerical coefficient deduced from experience done in laboratory: with: = 1.52*10⁻ᶾ (sobocinsky) = 1.42*10⁻ᶾ (bournazel) some useful data the following data were used as an input data to the simulator [4] 1pv t data pressure volume temperature data (pv t) are presented in english units in table (1) table (1), pvt data pressure psi rs liberated scf/bbl rs insolution cf/bbl b vol/vol shrinkage factor vol/vol 3450 0 1249.6 1.619 1 3000 193 1056 1.536 0.949 2500 381.4 868.2 1.454 0.898 2000 540 709.6 1.388 0.857 1500 694.1 555.5 1.324 0.818 1000 838.8 410.8 1.266 0.782 650 942.7 306.9 1.233 0.755 200 1096 153.6 1.153 0.712 0.698 60 11662 83.4 1.13 1.049 0.648 0 at 60◦f 1249.6 0 1 0.618 raad mohammed jawad. alkhalissi -available online at: www.iasj.net ijcpe vol.16 no.2 (june 2015) 55 2following table (2) shows the chemical composition of oil vs. weight percent table (2), composition and weight% composition weight% c1 0.3 c2 0.32 c3 0.51 ic4 0.97 nc4 4.86 ic5 7.75 nc5 9.4 c6ɟ 75.89 3formations depths (tops and bottom) from rtkb (m) and reservoir formations top as shown in table no.3 below [6] table (3), tops and bottoms of different layers layer top from rtkb/ m bottom from rtkb/ m rtkb m top m jeribe 2804 1868.5 284.05 1804 dhiban 18868.5 1913.8 1868.5 euphrates 1913 1926 1913.8 serikagni 1926 1955 1926 basal anhydrite _____ _____ ____ jaddala ------------- ------ 4as shown in table number 4 the oil density versus reservoir pressure table (4) oil density vs. pressure pressure psi oil density lb/ftᶾ 500 0.6783 4500 0.6751 4000 0.6719 5water saturation and porosity versus different reservoir layers, thickness are presented in table (5) below [6] table (5), thickness, water saturation and porosity versus reservoir layers building the model and finding a solution in order to build the model a suitable simulator must be used depending on the types of fluids in the field by determining to use a black oil field then builder of cmg simulator should be used. using pvt[4] information related to the x-well for our study to build the model using 4 layers totally of 400 meter and 100 meter of radius [6] perforated in the production zone (layer 3) given in the final well report[6] of the well chosen. the water coning problem appeared after running the simulator for 35 years and many steps were taken to avoid this problem. then next step were taken to avoid the water coning, and these steps are related to each other and were done consequently, layer thickness m water saturation fraction porosity fraction jeribe 18 0.4 0.19 dhiban 25 1 0.07 euphrates 18 0.3 0.2 serikagni 10.5 0.2 0.1 basal anhydrite 9.5 0.2 0.2 oligocene 25 0.8 0.1 jaddala 20 1 0.05 single well coning problem and applicable solutions 56 ijcpe vol.16 no.2 (june 2015) -available online at: www.iasj.net 1divide the 4 main layers to sub layers, totally 8 layers it help in minimizing the water coning. it was 13.24 mstb with layer 4 layered model and become 5.87 mstb, so it was minimized by 57% approximately ant this result is due to the decrease in water encroachment from limited aquifer size in one coning well model 2 change the perforation interval number instead of one layer perforation. 2 layers (the 4 th and 6 th ) were chosen to be perforated (in the 4 layers model, layer 3 was perforated) . this step made the perforation interval much less and on a higher level/ the water production was 5.87 mstb before this step and after it became 4.1 mstb, approximately it was minimized by 31% it is not effective as the previous one as a second step, but if this step were taken to be the first step the result will be minimizing the 13.24 mstb to 6.98 mstb, about 45% 3this step must be done within limit, not to exceed the original perforation depth. 4using one perforation area instead of two, but in this case the oil percentage will be minimized as well, so it is not a preferable step. 5trying to minimize the production period for the well, not to exceed 25 years in simulator, predicting for more than 25 years can cause many problems to occur while it might be unrealistic due to limited aquifer size in our one well model. conclusions 1dividing the model to sub layers 8 layers instead of 4 layers result in decreasing water coning by 57% can avoid and minimize the water coning 2changing perforations place and number (within limit) led to decrease coning by 45%. 3minimizing the production time in the simulator and increasing production period beyond 25 years resulted in many problems which is unrealistic. nomenclatures mstb: million standard barrel, pvt: pressure, volume and temperature, ∆p: pressure difference ( ), b: formation volume factor (vol/vol), q: flow rate ( ), µ: viscosity (cp), ln: natural logarithm, r: outer radius (m), r: well radius (m), g: acceleration= 9.81 (m/ ), qo: oil rate ( /day), ∆ρ in gm/ , k: permeability (md), µo: oil viscosity (cp), ht: total bed thickness (m), hp: perforated height (m) and ht: immobile phase height (m). references 1ali ghalambor (2007), petroleum production engineering a computer assisted approach. 2r.h. cotin (1979), elaboration of reservoir exploitation project. 3hussein rabia (2009), well engineering and construction. 4pvt report for x-well (2009). 5map for the northern iraq field with x-well coordination (2007). 6final well report for x-well. 7leonard f koederitz (2004), lecture notes on applied reservoir simulation. 8donald w. peaceman (1977), fundamentals of numerical reservoir simulation. iraqi journal of chemical and petroleum engineering vol.14 no.4 (december 2013) 4552 issn: 1997-4884 heterogeneously catalyzed esterification reaction: experimental and modeling using langmuirhinshelwood approach nada s. ahmedzeki, maha h. alhassani and hayder a. al-jandeel chemical engineering department, college of engineering, university of baghdad, baghdad, iraq abstract the esterification reaction of ethyl alcohol and acetic acid catalyzed by the ion exchange resin, amberlyst 15, was investigated. the experimental study was implemented in an isothermal batch reactor. catalyst loading, initial molar ratio, mixing time and temperature as being the most effective parameters, were extensively studied and discussed. a maximum final conversion of 75% was obtained at 70°c, acid to ethyl alcohol mole ratio of 1/2 and 10 g catalyst loading. kinetic of the reaction was correlated with langmuir-hanshelwood model (lhm). the total rate constant and the adsorption equilibrium of water as a function of the temperature was calculated. the activation energies were found to be as 113876.9 and -49474.95 kj per kmol of acetic acid for the esterification reaction and the heat of adsorption of water. these results agreed well with the previous published data. keywords: esterification, langmuirhinshelwood, heterogeneous catalyzed reaction introduction reactions catalyzed by a solid catalyst are having great attention. the ion exchange resins amberlyst-15 is as an excellent source of strong acid in non-aqueous media. it is a porous sulfonated polystyrene resin that had been explored as a powerful catalyst for various organic transformations and various catalyzed reactions, e.g., esterification, etherification, oxidation, hydration of olefins, condensation, cyclization and electrophilic aromatic substitution [1]. it has many advantages as that it is an inexpensive, non-hazardous solid acid, easily handled, and readily removed at the end of the reaction by simple filtration. an additional advantage is that the catalyst can be regenerated and used several times [2, 3]. esters are commonly used as solvents, diluents, extract ants, pharmaceuticals, and intermediates [4,5]. specifically, ethyl acetate primarily used as a solvent for removing pigments for nail varnishes and is responsible for the solvent effect for nail varnish remover. industrially, it is used for decaffeinate coffee beans and tea leaves and also as an activator hardener. it is present in confectionaries, fruits and is used in perfumes due to its fruity smell [6]. the traditional homogeneous catalytic reaction using liquid acids as the catalyst was the popular method for the preparation of these materials. but the drawback of the reaction like iraqi journal of chemical and petroleum engineering university of baghdad college of engineering heterogeneously catalyzed esterification reaction: experimental and modeling using langmuir hinshelwood approach 46 ijcpe vol.14 no.4 (december 2013) -available online at: www.iasj.net separation problems and the esterification of the acid catalyst itself producing co-products, made the search for other alternative method inevitable. a great deal of efforts had been concentrated on the development of solid acids to replace the conventional processes. heterogeneous kinetic models esterification reaction catalyzed by an ionexchange resin can be qualified by using different kinetic models for both the homogeneous and heterogeneous approaches. for high polar reaction, the pseudohomogeneous model (phm) can be used because complete swelling in the polymeric catalyst can be assumed, leading to an easy arrival of the reactants to the active sites. also (phm) does not pay attention to the sorption effect into the catalyst of different species in the reactant solution [7,8]. the langmuirhinshelwood model (lhm) includes the sorption effect in their kinetic model. the main idea of (lhm) is that all the reactants are adsorbed on the active sites of the catalyst surface before the start of chemical reaction [7]. delgado et al [7] (2007) suggested an experimental kinetics expression, based on (lhm), assuming that only water is being adsorbed on the catalyst. sattefield 1980 stated the advantages of (lhm) as:  the resultant rate equation may be extrapolated more accurately to concentrations beyond the range of experimental measurements used.  the method takes into account the adsorption and surface (which must occur) in a consistent manner. the present study is the extension of our previous study on the homogeneously catalyzed esterification reaction [9]. in this study the experimental data of the heterogeneous esterification of acetic acid with ethanol and the hydrolysis of ethyl acetate was correlated using langmuir hinshelwood approach. derivation of the rate equation the reaction mechanism as proposed in this study is that the protonated carboxyl group of the acidic resin reacts with alcohol [10]. the ethanol/ acetic acid esterification reaction is represented by the following equation: where, a= acoh, b=etoh, e=etoac, w=h2o the derivation of an expression for acetic acid esterification under different experimental condition is based on the following assumption: 1the reaction mixture was magnetically stirred at about 250 rpm. under this condition, with the appropriate catalyst particle size range, it was assumed that there was no internal or external transport limitations. this assumption agrees with the work of patricia et al [11] (2007), who established that external diffusion dose not control the overall reaction rate. while the negligible of internal diffusion agrees with popken et al [12] (2000) and patricia et al [11] (2007), who pointed out that intraparticle diffusion resistance is usually negligible for most of the reaction catalyzed by the amberlyst series resins. 2since only water adsorbed onto the amberlyst [12] in considerable amounts, the terms other than water can be neglected. to simplify the derivative of the reaction equation. 3for the heterogeneously catalyzed reaction, it was founded in the literature that the goodness of fit can be improved by using activities instead of mole fractions [9] , but in nada s. ahmedzeki, maha h. alhassani, hayder a.k. al-jandeel -available online at: www.iasj.net ijcpe vol.14 no.4 (december 2013) 47 our study mole fractions were used because this study exhibited similar performance with the previous study. the expression of the reaction rate can be described by kirbasilar [5] (2000): wwb ba a kcc cc kr   …(1) equation (1) can be rewritten in a straight line form as follows: b ww a a kc ck kr c   1 …(2) where, k is the total rate constant, and kw is the adsorption equilibrium constant of water. the esterification reaction shows a strong non-ideal behavior due to the presence of water and ethyl alcohol which are highly polar compared to the non-polar ethyl acetate. therefore, this non-ideality of the liquid phase was considered by using activities instead of mole fractions or concentrations [13]. the activity coefficients of the components at constant catalyst loading [14, 15] were calculated using unifacal program. therefore, equation (1) becomes: wwb ba a k kr     …(3) where αi represents the activity of species i which is defined as: …(4) γi is the activity coefficient and xi is the mole fraction. materials and method materials acetic acid of analytical grade (99.6%) gcc, and local commercial alcohol 95% were used. the strong acidic ion-exchange resin (amberlyst15), which supplies from sigma-aldrich was used as the catalyst. the specification is given by supplier, listed in table.1. the resin was washed with distilled water, dried at 100˚c over night and stored in a desiccator. procedure the study of the kinetics of esterification reaction was carried out in a thermostatic batch reactor. a volumetric flask of 500ml fitted with a long reflux condenser to prevent any loss. a magnetic stirrer type (stuart,) was used and the speed of 250 rpm which was high enough to eliminate external mass diffusion [16]. the aqueous acoh solution and amberlyst 15 were charged into the reactor and heated to the desired temperature. etoh was heated separately to the same temperature and was added the reaction mixture. this time accounts for the start of the reaction. samples were taken every 20 minutes by a syringe and analyzed by gas chromatography .experiments were carried out at temperature range of 4070˚c. values of temperature higher than this range causes an increase in the rate of the hydrolysis reaction as stated by ahmedzeki et al [9]., (2010). the acetic acid to ethanol molar ratio of 1/2 to 2 and catalyst loading of 0.52g were also studied. the volume of the reaction mixture remained constant during all experiments. the effect of particle size was not studied as it had found in literature that it had negligible effect [17] . where the macroporous resins consist of gel-type microspheres that form a macroporous polymer structure composing of very small microspheres which are similar in size. this result indicates indeed a mass transfer limitation. these observation agree well with the results reported by song et al [18] (1998). heterogeneously catalyzed esterification reaction: experimental and modeling using langmuir hinshelwood approach 48 ijcpe vol.14 no.4 (december 2013) -available online at: www.iasj.net effect of catalyst loading the relation between acetic acid conversion with various catalyst loading is shown in fig. 1. from this figure, it can be concluded that, the conversion increases with increasing catalyst loading due to an increase in the total number of active catalyst sites. table 1, specification of amberlyst 15 test specification hydrogen form, wet, moisture ,wt% 48 appearance (color) brown-grey appearance (form) granules 0.600 to 0.850 mm exchange capacity 1.7 meq/ml surface area 53 m 2 /g average pore diameter 300 ˚a total pore volume 0.40 ml/g max. operating temperature 120°c consequently the equilibrium is reached faster with increased catalyst loading. in the absence of mass transfer resistance, the initial rate of reaction is directly proportional to the catalyst loading. this further supports that the controlling mechanism is the surface reaction on the pore wall. at higher catalyst loading the rate of mass transfer is high and these are not significant increase in the rate. a similar trend was reported by yadav and thathaga [19] (2002). the maximum conversion approximately 0.75, was obtained for an acetic acid to ethyl alcohol molar ratio of m 1/2 with catalyst loading 10 g and temperature of 70 °c. 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0 50 100 150 200 250 300 tim e (m in) c o n v e r s io n 5 g 7 g 10 g fig. 1, effect of contact time on the acetic acid conversion of various catalyst loading , molar ratio of acetic acid to ethanol m 1/2 and temperature 70°c effect of initial reactant molar ratio the effect of the molar ratio of the reactants on the conversion of acetic acid is shown in fig.2. from this figure, it can be observed that as the mole ratio decreases, the conversion of acetic acid increases. as stated earlier, to shift the equilibrium towards the formation of the desired product, excess acetic acid was used to drive the equilibrium away toward ester formation [5,9]. the maximum conversion, approximately (0.68), was obtained for mole ratio of m=1/2 with catalyst loading of 5 g and temperature of 70 °c. 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0 50 100 150 200 tim e(m in) c o n v e r s io n 0.5 1 2 fig. 2, effect of molar ratio of acetic acid to ethanol on conversion of acetic acid (temperature 70°c, catalyst loading of 5 g) effect of temperature the effect of temperature is very important in order to calculate the activation energy of the reaction as shown in fig. 3. the conversion of esterification increases with increasing nada s. ahmedzeki, maha h. alhassani, hayder a.k. al-jandeel -available online at: www.iasj.net ijcpe vol.14 no.4 (december 2013) 49 reaction temperature within the range 40-70°c, when temperature increase up to 50°c, the rate of hydrolysis reaction is higher than esterfication rate [20] . in general, in esterification reaction, the equilibrium constant is a weak function of the temperature due to the small value of heat of reaction and for this reason the conversion was nearly low in the range of temperature considered in this work. these observations agree well with the results reported by (patricia et al [11] ., 2007). 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0 50 100 150 200 tim e (m in) c o n v e r s i o n 70°c 60°c 50°c 40°c fig. 3, effect of temperature on the conversion of acetic acid (m=1/2, catalyst loading of 5 g( kinetic modeling the kinetic data of the esterification was correlated with lhm, as shown in equation (2). according to the differential method, the rate of reaction can be found by finding of line tangent to the curve which represents the relationship between acetic acid concentration and time as shown in fig.4. at any temperature and at any given point. it enable the simultaneous determination of k,kw from slope and intercept of plot ra ca  ln and cb cw ln as shown in fig. 5,6,7 and 8 . the value of k, kw at various temperature are tabulated in table (2). 0 0.001 0.002 0.003 0.004 0.005 0.006 0.007 0 50 100 150 200 tim e c a 70°c 60°c 50°c 40°c fig. 4, experimental full line concentration of acetic acid of 40-70°c, m=1/2, catalyst loading of 5 g 4.5 4.6 4.7 4.8 4.9 5 5.1 0 0.2 0.4 0.6 0.8 1 1.2 ln(cw/cb) ln ( c a /r a ) fig. 5, experimental reciprocal rate equation plot at 70°c, m=1/2, catalyst loading of 5 g 4.5 4.6 4.7 4.8 4.9 5 5.1 5.2 5.3 0 0.2 0.4 0.6 0.8 1 ln(cw/cb) ln (c a /ra ) fig. 6, experimental reciprocal rate equation plot obtained of acetic acid at 60°c, m=1/2, catalyst loading of 5 g 0 1 2 3 4 5 6 7 8 -0.1 0 0.1 0.2 0.3 0.4 0.5 ln(cw/cb) ln ( c a /r a ) fig. 7, experimental reciprocal rate equation plot at 50°c, m=1/2, catalyst loading of 5 g heterogeneously catalyzed esterification reaction: experimental and modeling using langmuir hinshelwood approach 50 ijcpe vol.14 no.4 (december 2013) -available online at: www.iasj.net 0 1 2 3 4 5 6 7 8 -0.1 -0.05 0 0.05 0.1 0.15 0.2 0.25 ln(cw/cb) l n ( c a / r a ) fig. 8, experimental reciprocal rate equation plot at 40°c ,m=1/2, catalyst loading of 5 g table 2, the value of rate constant for esterfication and adsorption equilibrium constant for h2o t (°c) k(s -1 ) kw 40 0.0003 0.074 50 0.0051 0.01538 60 0.0129 0.013014 70 0.01468 0.012716 the constant of arrhenius equation, activation energy and frequency factor were determined from experiments, carried out at different temperature. the data of lnk, ln(kw) against 1/t were fitted by linear regression as shown in fig.9 and 10 respectively. the activation energies were found to be 113876.9 and -49474.95 kj. kmol -1 for esterfication reaction and the heat of adsorption for water. while the frequency factor of both reactions were 5.9*10 15 and 2.7*10 -10 respectively. applying the arrhenius equation to the value obtained from experiments, the temperature dependency of the constant were found to be: rt k 9.113876 316.36ln  …(5) rt kw 95.49747 034.22ln  …(6) the kinetic model with the fitted parameters can be written as follows: w rt b ba rt a cec cce dt dc ra 95.49474 10 9.113876 15 10*7.2 10*9.5     …(7) -9 -8 -7 -6 -5 -4 -3 -2 -1 0 0.0029 0.00295 0.003 0.00305 0.0031 0.00315 0.0032 0.00325 (1/t(k)) ln ( k ) fig. 9, arrhenius plot for esterification reaction of forward rate -5 -4 -3 -2 -1 0 0.0029 0.00295 0.003 0.00305 0.0031 0.00315 0.0032 0.00325 1/t ln ( k w ) fig. 10, arrhenius plot of adsorption for h2o conclusion from the present study, it was concluded that: 1the strong acidic resin can be used as a catalyst for the esterification of ethyl alcohol and acetic acid. the modification of this reaction as being switched from homogeneously catalyzed to heterogeneously catalyzed, may offer an easier way for the separation as compared with the conventional process. 2conversion of our case study reaction was found to increase with increasing catalyst loading, reaction time, temperature up to 70 o c and with decreasing acetic acid to ethyl alcohol mole ratio. maximum conversion of 75% was obtained using 5g of catalyst, mole ratio of nada s. ahmedzeki, maha h. alhassani, hayder a.k. al-jandeel -available online at: www.iasj.net ijcpe vol.14 no.4 (december 2013) 51 0.5 at a temperature of 70 o c and after three hours. 3results represent surface reaction control or mass transfer is not controlling. micro kinetics investigations as simulated by (lhm) revealed the applicability of this model to the experimental data. aactivation energies were found to be 113876.9 and -49474.95kj/mol for the esterification reaction and for the heat of adsorption of water respectively. references 1robert ronnback, tapio salmi, antti vuouri, heikki harrio, juha l., anna s., and esko t., 1997, development of a kinetic model for the esterification of acetic acid with methanol in the presence of a homogeneous acid catalyst, chem. eng. science, 52, 3369-3381. 2sheu houa r, wub j-.l, chengb ht.,, xieb y.t.,and ling-ching chenb l-c, 2008, amberlyst-15catalyzed novel synthesis of quinoline derivatives in ionic liquid, journal of the chinese chemical society, 55, 915-918. 3harmer, m.a. , 2002, industrial processes using solid acid catalysts, in handbook of green chemistry and technology; clark, j. h.; macquarris, d. j.; eds.; blackwell publishers: london; pp. 86-117. 4sans m. t,gmehling j.,2006, esterification of acid with isopropanol coupled with prevaporation part i: kinetics and prevaporation, chem.eng.j., 123,18. 5kirbasilar s.i. ,baykal b., dramur u., 2001, esterification of acetic acid with ethanol catalyzed by acidic ion exchange resin, turk. j.eng. environ. sci., 25, 569-577. 6kirk r.e. and othmer d.f., 1980, encyclopedia of chemical technology, 9,291-298, wiley andsons.inc.new york. 7delagado p., sans m. t., beltvan s., ,2007, kinetic study for esterification of lactic acid with ethanol and hydrolysis of ethyl acetate using an ion exchange resin, chem. eng. j.,120,1-8. 8calvar n., gonzalez b., domingues a., 2007, esterification of acetic acid with ethanol reaction kinetics and operation in packed bed reactive distillation column, chem. eng., and processing, 46, 13171327. 9ahmedzeki n.s, al-hassani m., aljendeel h, 2010, kinetic study of esterification reaction, alkhwarizmi eng. j., 25,2, 33-42. 10foglar, h.s., 1992. elements of chemical reaction engineering, prenticehall inc, new jersey. 11patricia d.,maria t.s., sagrario b. 2007,”kinetic study for esterification of lactic acid with ethanol and hydrolysis of ethyl lactate using an ion exchange resin catalyst”, chem. eng. journal,126, 111-118. 12popken t., gotee t., gmehling j., 2000, reaction kinetics and chemical equilibrium of homogeneously and heterogeneously catalyzed acetic acid esterification with methanol and methyl acetate hydrolysis, ind. eng. chem. res. 39, 2601-2611. 13keurentjes, j.t.f., janssen, g.h.r. and gorissen, j.j., 1994, the esterification of tartaric acid with ethanol; kinetic and shifting the equilibrium by means of prevaporation. chem.eng. sci. 49, 4681-4689. 14zhu, y.r.g. minet and t.t. tsotsis, 1996, a continuous prevaporation membrane reactor for the study of esterification reaction using a composite polymeric/ ceramic membrane, chem. eng. sci., 5 , 51,17,4103. heterogeneously catalyzed esterification reaction: experimental and modeling using langmuir hinshelwood approach 52 ijcpe vol.14 no.4 (december 2013) -available online at: www.iasj.net 15pransit, j.m. anderson t.f., grens e.a., eckert c.a. hsieh, r. and oconuell, j.p., 1980, computer calculation multicomponent vaporliquid and liquid-liquid equilibrium, prentice-hall, englewood cliffs, nj. 16pipus, g., plazl.i., koloini.t., 2000, esterfication of benzoic acid in microwave tubular flow reactor, chemical engineering journal, 76, 239-245. 17pitochelli a.r. 1980, ion exchange catalyst and matrix effect rohm and hass co.philadeiphia,pa. 18song w., venimadhavan g., manning j.m., malone m. dohrty, 1998, measurement residue curve maps and heterogeneous kinetics in methyl acetate synthesis, ind. eng. res., 37, 1917. 19yadav g.d., m.b. thathagar. 2002, esterification of meteic acid with ethanol over cation – exchange resin catalysyt. reactive and functional polymers, 52 (99-110). 20liu w.t., c.s.tan, 2001, liquid phase esterfication, end.eng. chem. res., 40, 3281-3286. iraqi journal of chemical and petroleum engineering vol.12 no.4 (december 2011) 37-51 issn: 1997-4884 improved method to correlate and predict isothermal vle data of binary mixtures venus majeed bakall bashy al-temimi abstract accurate predictive tools for vle calculation are always needed. a new method is introduced for vle calculation which is very simple to apply with very good results compared with previously used methods. it does not need any physical property except each binary system need tow constants only. also, this method can be applied to calculate vle data for any binary system at any polarity or from any group family. but the system binary should not confirm an azeotrope. this new method is expanding in application to cover a range of temperature. this expansion does not need anything except the application of the new proposed form with the system of two constants. this method with its development is applied to 56 binary mixtures with 1120 equilibrium data point with very good accuracy. the developments of this method are applied on 13 binary systems at different temperatures which gives very good accuracy. keywords: vle, vapor liquid equilibrium, isothermal data prediction, new thermodynamic relation, vle of binary mixtures. 1. introduction: there are so many applications of vle; therefore, techniques for calculation and experimental determination of this particular type of phase equilibrium are more highly developed than any other thermodynamic types. therefore, this subject should be the first of the application to be mastered. besides the complexity of running vle experiment at constant temperature it is expensive. hence it would be of great advantage to be able to predict the shape of the vle curve without the need to run an experiment. [1] many methods are suggested to predict vle data which are summarized here. 2. methods for vle calculation: the methods usually used to calculate vle data can be summarized as follows: a. vle data from eos: eos and ceos have a theoretical aspect through the derivation. many forms are introduced to calculate vle data based on the required conditions, and the type of systems like rk eos [2], srk eos [3], pr eos [4], prsv eos [5], etc. besides it is capable to represent vapor and liquid phases, it has many short comes. so, efforts are directed to improve it. vle calculation by an eos is difficult to treat unsymmetrical mixtures. therefore, adjustable parameters are university of baghdad college of engineering iraqi journal of chemical and petroleum engineering improved method to correlate and predict isothermal vle data of binary mixtures 38 ijcpe vol.12 no.4 (december 2011) available online at: www.iasj.net introduced in order to fit the experimental data. [6] all the introduced adjustable parameter or parameters need an experimental data points in order to be evaluated at certain temperature and pressure. another out-come appears through the calculation of vle by eos where for various systems there is a number of equations of states; each is specified to certain temperature and pressure ranges, polarity, or hydrocarbon cut. this is a reason why there are a very large number of equations of state instead of one eos representing all systems in all conditions. b. models to predict vle data: these models are much more empirical in nature when compared to the property predicted from eos which is typically used in the hydrocarbon mixtures. the tuning parameters of any activity models should be fitted against a representative sample of experimental data and their application which should be limited to moderate pressure and usually these constants are subjects to single temperature. consequently, more caution should be exercised when selecting these models for particular simulation. the individual activity coefficient for any system can be obtained from derived expression for excess gibbs duhem equation. [7] the early models (margules [8], van laar [8]) provide an empirical representation of vle and that limits their application. the newer models such as wilson [9], nrtl [8], uniquac [8], and unifac [10] utilize the local composition concept and improvement in their general application and reliability. all these models involve the concept of binary interaction parameters and require that they be fitted to experimental data. [7] the activity coefficient models are used as a tool for phase equilibrium calculations. all such models are empirical in nature and represent the activity coefficient of a component in a mixture (and hence its fugacity) in terms of an equation that contains a set of parameters. two general approaches are employed: i. the parameters of activity coefficient model are determined in a fit to experimental vle data in a binary mixture; in this sense, these models are only a correlation for the binary systems. although they may allow extrapolation with respect to temperature or pressure but it is truly predictive for multicomponent systems. examples of these models are wilson, tk-wilson [8], nrtl, and uniquac activity coefficient models. ii. an alternative approach, which requires no experimental data, is one in which the parameters of the activity coefficient model are estimated by group contribution method. several such schemes have been developed with functional group parameters determined by regression against a very large data base of experimental vle results. examples of these approaches are asog [11] and unifac [10] models. [12] 3. new method to predict isothermal vle data: prediction of vle data is one of the most important objects of researchers for centuries. because of the difficulties associated with the experiments and the error might happen during the experiment. so, a predictive tool is needed. this correlation is based on a statistical hypothesis and the flexibility of the proposed function to represent vle venus majeed bakall bashy al-temimi available online at: www.iasj.net ijcpe vol.12 no.4 (december 2011) 39 data for a binary mixture at certain temperature. since all the previous method and approaches used to calculate or predict vle data with numerical or physical base need constants in order to eliminate the deviation or error which appears in comprised with the experimental data. this method benefits from the mathematical behavior of exponential function when representing the vle data of isothermal binary mixtures. this method can calculate vle data at any vapor composition at certain temperature with the need of two constants values for the binary at that temperature. the proposed function has the following form: p = a exp( b y ) …………………..(1) where: p= saturation pressure for the selected binary mixture and is taken in mmhg for these constants. a, and b= equation constants for specified mixture at certain temperature y= vapor phase mole fraction for any binary mixture, there are binary constant which are (a and b). these constants remain unchanged for the same binary mixture at certain temperature over the whole system composition; i.e, this simple relation can give p, x, y diagram representation for the binary mixture where x (liquid phase mole fraction) can be calculated by flash calculation. this method is very simple in application with reasonable accuracy if it is compared to previously used methods for vle calculation. all of the used constants are specified for each system in order to match the experimental data in spite that some of them have a theoretical base. besides the simplicity of the proposed equation, it can be applied to polar and non polar systems at any conditions and from any group except the mixtures which confirm azeotropes. because of this limitation the proposed equation behaves as an exponential function. also, the new form can be applied for all systems temperatures and compositions ranges. the proposed equation is applied on 56 different mixtures at different temperatures that range from different groups or families with 20 data points for each binary mixture at certain temperature; i.e, 1120 data points for all binary mixtures with very reasonable accuracy as shown in table (1), where r 2 is called a recursion formula. it represents a statistical measure that represents the deviation from the proposed method. when r 2 approaches one, very good representation of equation is obtained. while, if recursion formula approaches zero, a very poor representation is obtained. to see the graphical behavior of the proposed function which has a solid line representation with the experimental data representing figures by shapes for the whole system composition range at different temperatures. the figures are: fig. 1, n-heptane + benzene system 0 2000 4000 6000 8000 10000 0 0.2 0.4 0.6 0.8 1 p re ss u re (m m h g ) benzene vapor mole fraction t=45 t=60 t=75 t=80 t=110 t=125 t=140 improved method to correlate and predict isothermal vle data of binary mixtures 40 ijcpe vol.12 no.4 (december 2011) available online at: www.iasj.net table 1, new proposed equation constants and its accuracy no. system [13] temp. o c equation 1 constants r 2 a b 1 n-heptane + benzene 45 115.7529 0.7278 0.9880 60 213.6991 0.6677 0.9872 75 363.5689 0.6311 0.9891 80 436.0013 0.6071 0.9879 110 1072.1799 0.5597 0.9893 125 1609.5652 0.5102 0.9664 140 2272.9713 0.4920 0.9848 155 3123.5234 0.4659 0.9924 170 4248.2850 0.4402 0.9947 185 5607.0912 0.4258 0.9973 2 n-heptane + toluene 25 30.3824 0.4636 0.9574 30 38.9761 0.4530 0.9581 40 62.1667 0.4434 0.9547 3 n-heptane + 1-chlorobutane 30 58.45 0.812 0.9970 50 142.3911 0.7317 0.9965 80 431.4 0.6419 0.9966 4 n-butane + 1-butene 37.8 2727.3818 0.1596 0.9179 51.7 3860.5502 0.1777 0.9205 65.6 5512.6930 0.1703 0.9344 5 n-butane + 1,3-butadiene 37.8 2727.3818 0.1596 0.9179 51.7 3926.7768 0.1397 0.9205 65.6 5600.6035 0.1341 0.9344 6 n-octane + benzene 55 42.0097 1.9801 0.9652 65 83.3906 1.626 0.9669 75 120.2414 1.6121 0.9715 7 n-decane + toluene 100.4 48.81 2.2036 0.9177 110.5 75.7478 2.1146 0.9337 120.6 127.9465 1.9380 0.9836 8 carbon tetrachloride + toluene 35 39.9962 1.3598 0.9671 40 51.0098 1.3297 0.9691 45 64.3979 1.2869 0.9707 55 99.8127 1.2233 0.9730 65 149.8724 1.1633 0.9756 9 carbon tetrachloride + 2,4,4 trimethylpentane 35 77.6443 0.8085 0.9964 45 117.4508 0.7869 0.9937 55 175.1214 0.7483 0.9914 65 254.1325 0.7184 0.9905 10 methanol + water 35 35.7739 1.6956 0.9804 39.8 45.0487 1.7007 0.9721 50 78.8519 1.6149 0.9810 60 131.2698 1.5336 0.9856 65 173.1995 1.4649 0.9873 100 728.2713 1.2615 0.9935 140 2651.8723 1.1504 0.9974 11 ethane + propane -145.5 0.0624 4.1169 0.7159 -128.9 0.7112 3.5759 0.7752 -101.1 11.836 2.9892 0.8839 -73.3 96.7761 2.4878 0.8895 -70 191.4197 2.0470 0.9678 12 1,2dichloroethane + isoamylalcohol 50 12.5169 2.7301 0.8899 60 25.0624 2.4697 0.9134 70 45.2774 2.2645 0.9288 80 77.5508 2.0834 0.9422 13 n-heptane + ethylbenzene 25 7.8495 1.6876 0.9759 40 18.2654 1.5563 0.9796 54.6 38.0839 1.445 0.9759 venus majeed bakall bashy al-temimi available online at: www.iasj.net ijcpe vol.12 no.4 (december 2011) 41 fig. 2, n-heptane + toluene system fig. 3, n-heptane + 1-chlorobutane system fig. 4, n-heptane + ethylbenzene system fig. 5, n-butane + 1-butene system fig. 6, n-butane + 1,3-butadiene system fig. 7, n-octane + benzene system 0 20 40 60 80 100 120 0 0.2 0.4 0.6 0.8 1 p re ss u re (m m h g ) toluene vapor mole fraction t=25 t=30 t=40 0 200 400 600 800 1000 0 0.2 0.4 0.6 0.8 1 p re ss u re (m m h g ) 1-chlorobutane vapor mole fraction t=30 t=50 t=80 0 40 80 120 160 200 0 0.2 0.4 0.6 0.8 1 p re ss u re ( m m h g ) nheptane vapor mole fraction t=40 t=54.6 t=25 0 1000 2000 3000 4000 5000 6000 7000 0 0.2 0.4 0.6 0.8 1 p re ss u re (m m h g ) 1-butene vapor mole fraction t=37.8 t=51.7 t=65.6 0 1000 2000 3000 4000 5000 6000 7000 0 0.2 0.4 0.6 0.8 1 p re ss u re (m m h g ) 1,3-butadiene vapor mole fraction t=37.8 t=51.7 t=65.6 0 100 200 300 400 500 600 700 0 0.2 0.4 0.6 0.8 1 p re ss u re (m m h g ) benzene vapor mole fraction t=55 t=65 t=75 improved method to correlate and predict isothermal vle data of binary mixtures 42 ijcpe vol.12 no.4 (december 2011) available online at: www.iasj.net fig. 8, n-decane + toluene system fig. 9, carbon tetrachloride + toluene system fig. 10, carbon tetrachloride +trimethylpentane system fig.11, methanol + water system fig. 12, 1,2 dichloroethane + isoamylalcohole system fig.13, ethane + propane system 0 200 400 600 800 1000 1200 0 0.2 0.4 0.6 0.8 1 p re ss u re (m m h g ) toluene vapor mole fraction t=100.4 t=110.5 t=120.6 0 100 200 300 400 500 600 0 0.2 0.4 0.6 0.8 1 p re ss u re ( m m h g ) carbon tetrachloride vapor fraction t=35 t=40 t=45 t=55 t=65 0 100 200 300 400 500 600 0 0.2 0.4 0.6 0.8 1 p re ss u re ( m m h g ) carbon tetrachloride vapor fraction t=35 t=45 t=55 t=65 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 0 0.2 0.4 0.6 0.8 1 p re ss u re ( m m h g ) water vapor mole fraction t=35 t=39.8 t=50 t=60 t=65 t=100 t=140 0 100 200 300 400 500 600 700 800 0 0.2 0.4 0.6 0.8 1 p re ss u re ( m m h g ) 1,2 dichloroethane vapor fraction t=50 t=60 t=70 t=80 0 300 600 900 1200 1500 1800 2100 0 0.2 0.4 0.6 0.8 1 p re ss u re ( m m h g ) ethane vapor mole fraction t= (-145.5) t= (-128.9) t= (-101.1) t= (-73.3) t= (-70) venus majeed bakall bashy al-temimi available online at: www.iasj.net ijcpe vol.12 no.4 (december 2011) 43 4. improving the new proposed function in order to expand the applicability of the proposed equation, a new method is introduced. the improved method tries to calculate the equation constants at any temperature within a certain temperature range. it is noticed that (a and b) constants are functions of experiment temperature. the a and b proposed function or formulas have the following forms: a = a e bt ….…….…(2) …..………(3) where: a, b : equation (1) constants values specified for each binary mixture a, b, a * , b * : are new constants for each binary system at certain temperature range. t : the required temperature measured in ( o c) needed to calculate the constants. the shape of the proposed relations and its fitting to the experimental data are given in the following figures: temperature – a constant relationship temperature – b constant relationship fig. 14, n-heptane + benzene system for a, and b constants relations fig. 15, n-heptane + toluene for a and b constants relations fig. 16, n-heptane + 1,chlorobutane for a and b constants relations y = 43.958e0.0274x r² = 0.9863 0 2000 4000 6000 8000 0 50 100 150 200 a c o n st a n t va lu e s temperature( oc) y = 0.8403e-0.0038x r² = 0.9920 0.4 0.5 0.6 0.7 0.8 0 50 100 150 200 b c o n st a n t va lu e s temperature( oc) y = 9.2887e0.0476x r² = 0.9997 20 30 40 50 60 70 10 20 30 40 50 a c o n st a n t va lu e s temperature ( oc) y = 0.4961e-0.0029x r² = 0.9556 0.44 0.445 0.45 0.455 0.46 0.465 20 25 30 35 40 45 b -c o n st a n t va lu e s temperature ( oc) y = 18.3916e0.0397x r² = 0.9973 0 100 200 300 400 500 0 20 40 60 80 100 a c o n st a n t va lu e s temperature (oc) y = 0.9305e-0.0047x r² = 0.9976 0.4 0.5 0.6 0.7 0.8 0.9 0 20 40 60 80 100 b co n st a n t va lu e s temperature (oc) improved method to correlate and predict isothermal vle data of binary mixtures 44 ijcpe vol.12 no.4 (december 2011) available online at: www.iasj.net fig. 17, n-heptane + ethylbenzene for a and b constants relations fig. 18, n-butane + 1-butene for a and b constants relations fig. 19, n-butane + 1,3-butadiene for a and b constants relations fig. 20, n-octane + benzene for a and b constants relations y = 2.0975e0.0534x r² = 1.0000 0 10 20 30 40 50 20 30 40 50 60 a c o n st a n t va lu e s temperature ( oc) y = 1.9178e-0.0052x r² = 1.0000 1.4 1.5 1.6 1.7 0 20 40 60 b c o n st a n t va lu e s temperature ( oc) y = 1,046.0643e0.0253x r² = 0.9999 0 1000 2000 3000 4000 5000 6000 20 40 60 80 a c o n st a n t va lu e s temperature ( oc ) y = 0.1498e0.0023x r² = 0.3597 0.155 0.16 0.165 0.17 0.175 0.18 20 40 60 80 b c o n st a n t va lu e s temperature ( oc ) y = 1,026.9113e0.0259x r² = 0.9999 2000 3000 4000 5000 6000 0 20 40 60 80 a c o n st a n t va lu e s temperature ( oc ) y = 0.1991e-0.0063x r² = 0.9144 0.08 0.12 0.16 0.2 20 40 60 80 b c o n st a n t va lu e s temperature ( oc ) y = 2.4578e0.0526x r² = 0.9701 30 50 70 90 110 130 150 40 50 60 70 80 a c o n st a ts v a lu e s temperature ( oc ) y = 3.3776e-0.0103x r² = 0.7813 1 1.5 2 2.5 50 60 70 80 b c o n st a n t va lu e s temperature ( oc ) venus majeed bakall bashy al-temimi available online at: www.iasj.net ijcpe vol.12 no.4 (december 2011) 45 fig. 21, n-decane + toluene for a and b constants relations fig. 22, carbon tetrachloride + toluene for a and b constants relations fig. 23, carbon tetrachloride + trimethyl pentane for a and b constants relations fig. 24, methanol + water for a and b constants relations y = 0.4001e0.0477x r² = 0.9974 0 20 40 60 80 100 120 140 90 100 110 120 130 a c o n st a n t va lu e s temperature ( oc ) y = 4.2044e-0.0064x r² = 0.9590 1.9 2 2.1 2.2 2.3 80 100 120 140 b c o n st a n t va lu e s temperature ( oc ) y = 8.7652e0.0439x r² = 0.9989 0 40 80 120 160 200 0 25 50 75 a -c o n st a n t va lu e s temperature ( oc ) y = 1.6353e-0.0053x r² = 0.9985 1.15 1.2 1.25 1.3 1.35 1.4 20 35 50 65 80 b co n st a n t va lu e s temperature ( oc ) y = 19.6302e0.0396x r² = 0.9994 0 100 200 300 20 40 60 80 a c o n st a n t va lu e s temperature ( oc ) y = 0.9363e-0.0040x r² = 0.9879 0.68 0.72 0.76 0.8 0.84 20 40 60 80 b c o n st a n t va lu e s temperature ( oc ) y = 9.9564e0.0412x r² = 0.9896 0 1000 2000 3000 4000 0 50 100 150 a c o n st a n t va lu e s temperature ( oc ) y = 1.9446e-0.0040x r² = 0.9735 1 1.2 1.4 1.6 1.8 0 50 100 150 b c o n st a n t va lu e s temperature ( oc ) improved method to correlate and predict isothermal vle data of binary mixtures 46 ijcpe vol.12 no.4 (december 2011) available online at: www.iasj.net fig. 25, ethane + propane for a and b constants relations fig. 26, 1,2-dichloro ethane + isomamyl alcohole for a and b constants relations the improvement of the new method constants extend the application of system constant to a range of temperature depending on a, b, a * , and b * as the calculated range for the heat capacity constants calculation. the new constants calculation method is applied on 13 systems with different temperatures range and from different groups or families as shown in table (2). table (2) shows very good applicability for the extend temperature range. now, if any researchers needs vle data for a selected system at a selected temperature within the constant temperature range the following steps should be followed: 1. find constant a, b, a * , and b * from a table for a certain binary mixture. 2. select the required temperature which should be within the constant range. 3. substitute the constants a, b and the temperature in eq 2 to calculate a constant. 4. substitute the constants a * , b * and the temperature in eq 3 to calculate b constant. 5. substitute the obtained constants a and b in eq. 1 to calculate saturation pressure at any vapor mole fraction. 6. make flash calculation at this temperature, pressure, and vapor mole fraction to calculate liquid mole fraction. 7. draw p, x, and y figure and also, x, y figure. this method really lowers the experimental cost and the difficulty associated with the experiment where at high pressure the vle experiment is very difficult to manage and expensive. y = 214,468.3934e0.1006x r² = 0.9882 0 50 100 150 200 -200 -150 -100 -50 a co n sta n t va lu e s temperature ( oc) y = 1.2677e-0.0081x r² = 0.9497 1 2 3 4 5 -150 -100 -50 0 b co n sta n t va lu e s temperature ( oc) y = 0.6295e0.0606x r² = 0.9966 0 20 40 60 80 100 40 50 60 70 80 90 a c o n st a n t va lu e s temperature ( oc) y = 4.2567e-0.0090x r² = 0.9981 1.8 2 2.2 2.4 2.6 2.8 40 55 70 85 b c o n st a n t va lu e s temperature ( oc) venus majeed bakall bashy al-temimi available online at: www.iasj.net ijcpe vol.12 no.4 (december 2011) 47 table 2, the new improved relation constants 5. discussion prediction of vle data is one of the most important objectives of the researchers for centuries. because of the difficulties associated with the experiments and because error might happen through the experiment, a predictive tool is needed. historically eos is used to predict vle data and the researchers tried to improve eos in order to be capable of representing vle data. besides the capability of eos to predict vle data, it has many short comes. the most important of them is the incapability of eos to represent all components and component mixtures; in other word the equations of state are classified according to component families or groups (polar, non-polar, ketones, hydrocarbons, heavy hydrocarbons, light hydrocarbons, alcohols …etc.) and also, according to the operation condition; i.e (system temperature and pressure). till the eighties of the past century, researchers turn to improve eos approximately stopped and the improvement of eos mixing rules was adopted. eos mixing rules has also a short out-comes. its short comes is that different forms depend on mixing rules. one of the most important short comes is that mixing rules share with it the adjustable parameter introduced in order to eliminate the deviation of each mixture from the ideal mixture which eos hypothesis based on through its derivation. while, the other methods adopted to calculate vle data have a number of constants specified for each system; this makes these methods also difficult to work with. this work over comes all the short comings of eos without any no. system no. of points temp. range o c eq. 2 constants r 2 eq. 3 constants r 2 a b a * b * 1 n-heptane + benzene 100 45_185 43.958 0.0274 0.9863 0.8403 -0.0038 0.992 2 n-heptane + toluene 30 25_40 9.2887 0.0476 0.9997 0.4961 -0.0029 0.9556 3 n-heptane + 1-chlorobutane 30 30_80 18.3916 0.0397 0.9973 0.9305 -0.0047 0.9976 4 n-butane + 1-butene 30 37.8_65.6 1046.0643 0.0253 0.9999 0.1498 0.0023 0.3597 5 n-butane + 1,3-butadiene 30 37.8_65.6 1026.9113 0.0259 0.9999 0.1991 -0.0063 0.9144 6 n-octane + benzene 30 55_75 2.4578 0.0526 0.9701 3.3776 -0.013 0.7813 7 n-decane + toluene 30 100.4_120.6 0.4001 0.0477 0.9974 4.2044 -0.0064 0.959 8 carbon tetrachloride + toluene 50 35_65 8.7652 0.0439 0.9989 1.6353 -0.0053 0.9985 9 carbon tetrachloride + 2,4,4 trimethylpentane 40 35_65 19.6302 0.0395 0.9994 0.9363 -0.0040 0.9735 10 methanol + water 70 35_140 9.9564 0.0412 0.9896 1.9446 -0.0040 0.9735 11 ethane + propane 50 -145.5_-70 214468.3934 0.1006 0.9882 1.2677 -0.0081 0.9497 12 1,2dichloro ethane + isoamylalcohol. 40 50_80 0.6295 0.0606 0.9966 4.2567 -0.0090 0.9981 13 n-heptane + ethylbenzene 30 25_54.6 2.0975 0.0534 0.9990 1.9178 -0.0052 0.9993 improved method to correlate and predict isothermal vle data of binary mixtures 48 ijcpe vol.12 no.4 (december 2011) available online at: www.iasj.net theoretical base but the need of two constants which represent the binary system mixture under the temperature range which the temperature constants accept it. so, the researchers can obtain very accurate experimental data points for any required temperature within the temperature range of the constants which represent that binary mixture. besides its capability to represent vle data with the system vapor pressure at any needed temperature this method is very simple to apply with very good accuracy compared with other used methods as will be seen in table (3). the improved relation is derived from the observation of the regular transmission behavior of the same mixture from temperature to another at constant pressure. this relation can be applied to all types of binary mixtures at any conditions except the mixtures which confirm azeotropes because the inabilities of the exponantional function to represent the vle data of azeotropes. also, from the table results one can observe that systems under very low temperatures or in other word negative experiment condition will give less accurate results compared with positive temperature of the experimental conditions results. noting that these proposed relations is function to component with higher vapor pressure. the error associated with the experimental data also affected the accuracy of the derived relation and this can be shown clearly when representing the data with poor r 2 factor for different binary mixtures. this method compared with antoine equation to calculate vapor pressure with the need to three constants. this method needs only these constants at certain temperature. besides that, this method can be modified to calculate the vapor pressure of any binary mixture at any temperature with the need of four constants at acceptable range temperature. this improvement cannot be achieved by antoine or any other equation with very good accuracy. venus majeed bakall bashy al-temimi available online at: www.iasj.net ijcpe vol.12 no.4 (december 2011) 49 table 3, comparison between the accuracy of the systems after and before applying the improving of the proposed correlation system temp. ( o c) a constant from eq. 2 b constant from eq. 3 abe% at exact a, and b values eq.1 abe% at general a, and b values eq. 2&3 n-heptane + benzene 45 150.8426 0.7082 1.7707 2.8782 60 227.5197 0.6690 1.6750 6.5731 75 343.1736 0.6319 1.5005 5.5489 80 393.5613 0.6200 1.5187 9.0305 110 859.3699 0.5532 1.4256 1.6787 125 1350.5091 0.5226 2.2304 1.5458 140 2037.0071 0.4936 1.4271 1.0283 155 3072.4695 0.4663 0.9856 1.7633 170 4634.2836 0.4404 0.8001 9.1080 185 699.0075 0.4160 0.5687 2.3999 over all abe% 1.39024 4.15547 n-heptane + toluene 25 30.53271 0.4614 2.2558 2.2695 30 38.73713 0.4548 2.1803 2.2935 40 62.35218 0.4418 2.2927 2.2831 over all abe% 2.2429 2.2820 n-heptane + 1-chlorobutane 30 60.5152 0.8081 0.8944 3.1636 50 133.8733 0.7356 1.0102 6.1097 80 440.4928 0.6389 0.8709 1.8830 over all abe% 0.92517 3.7188 n-butane + 1-butene 37.8 2721.854 0.1634 1.1944 1.1945 51.7 3868.951 0.1687 0.2633 0.4284 65.6 5499.479 0.1742 0.0779 0.0977 over all abe% 0.51187 0.57353 n-butane + 1,3-butadiene 37.8 2733.48 0.1569 1.1944 1.2178 51.7 3918.017 0.1437 1.0293 1.0251 65.6 5615.865 0.1317 0.8956 0.8785 over all abe% 0.70643 1.04047 n-octane + benzene 55 49.5091 1.6523 6.2710 11.8731 65 78.3477 1.4509 6.9992 6.9904 75 123.9846 1.2740 6.0223 9.0550 over all abe% 6.43083 9.30617 n-decane + toluene 100.4 48.0883 2.2113 14.3077 13.4844 110.5 77.85197 2.0729 11.9136 11.8038 120.6 126.0375 1.9431 4.8759 4.5214 over all abe% 10.36573 9.93653 carbon tetrachloride + toluene 35 40.7432 1.3584 5.5607 5.0466 40 50.7438 1.3229 5.6526 5.2520 45 63.1991 1.2883 5.2505 5.1291 55 98.0316 1.2218 4.8305 5.2396 65 152.0622 1.1587 4.4040 6.4604 over all abe% 5.13966 5.42554 carbon tetrachloride + 2,4,4 trimethylpentane 35 78.4977 0.8085 1.2127 1.5779 45 116.6373 0.7821 1.3823 1.4740 55 173.3078 0.7514 1.6183 1.7135 65 257.5127 0.7219 1.5679 2.4187 over all abe% 1.4453 1.79603 methanol + water 35 42.1071 1.6906 4.6667 6.8630 39.8 51.3146 1.6584 5.7752 4.6207 50 78.8519 1.5921 4.3085 4.7792 60 117.9447 1.5297 3.6429 5.3192 improved method to correlate and predict isothermal vle data of binary mixtures 50 ijcpe vol.12 no.4 (december 2011) available online at: www.iasj.net 6. conclusion  the proposed relation can represent vle data without a need to any other relation except two constants that represent each binary system at the specified temperature like any other constants introduced through historically used relations.  the improving of this relation made it very elastic in representing a very large rang of vle data of the binary systems.  the derivation of the constants should cover the required calculated vle temperature.  when the temperature range increases the error slightly increases.  the results of calculation show that constant a has a more effect than b on the accuracy of calculated vle data.  the obtained error might be from the experimental error causing an error through vle calculation.  the calculated constants are functions of the component and experimental temperature.  this equation can calculate the systems with higher vapor pressure without the need to run an experiment.  experiment run under negative temperature will give less accurate results compared with that at positive experimental temperature. abbreviations references: 1. harold a. beaty, and george calingaert, (1934), "vapor liquid equilibrium of hydrocarbon mixtures", ind. and eng. chem., vol. 26, no. 5, pp. (504) 2. smith, j. m., van ness, h.c., abbott, m. m., (2004), "introduction to chemical engineering thermodynamics", mcgraw-hill companies. 3. soave, g., (1972), "equilibrium constants from a modified rk eos", chem. eng. scie., vol. (27), pp. (1197). 4. ding-yu peng, and donald b. robinson, (1976), " a new two 65 144.9249 1.4994 3.3458 7.1379 100 612.9084 1.3035 2.2133 6.5336 140 3185.025 1.1108 1.2889 8.9827 over all abe% 3.6059 6.3195 ethane + propane -145.5 0.0943 4.1196 23.0094 17.3828 -128.9 0.5009 3.6013 17.4166 31.7519 -101.1 8.20922 2.8752 13.6966 33.4154 -73.3 134.5502 2.2955 9.15259 10.4304 -70 187.526 2.2349 6.4944 6.7880 over all abe% 13.9539 19.9537 1,2dichloroethane + isoamylalcohol 50 13.0289 2.7142 6.2004 7.3514 60 23.8831 2.4806 3.4433 4.6633 70 43.7797 2.2671 6.2076 2.1002 80 80.2519 2.0720 5.2163 9.5582 over all abe% 5.2669 5.9183 n-heptane + ethylbenzene 25 7.9705 1.6840 5.2406 3.9192 40 17.7564 1.5577 4.5968 5.1011 54.6 38.7212 1.4438 3.8001 3.9025 over all abe% 4.54583 4.3076 all systems over all abe% 4.3485 5.7487 abe average absolute error ceos cubic equation of state eos equation of state vle vapor liquid equilibrium venus majeed bakall bashy al-temimi available online at: www.iasj.net ijcpe vol.12 no.4 (december 2011) 51 constants eos", ind. eng. fandam., vol. 15, no. 1, pp. (59). 5. stryjek, r., and vera, j. h., (1986), "prsv: an improved pr eos of pure components and mixtures", the cand. j. of chem. eng., vol.64, pp. (323). 6. soave, g., (1993), "20 years of rk eos", fluid phase equilibrium, vol. 82, pp. (345). 7. hysys company, (2001), "property methods and calculation"), ver. 2 manual 8. smith, j. m., van ness, h.c., abbott, m. m., (1996), "introduction to chemical engineering thermodynamics", mcgraw-hill companies. 9. wilson, g. m., (1964), j. am. chem. soc., vol. 86, pp. (127). 10. gmehling, j., and rasmussen, p., and fredenslund, aa, (1982), "vle by unifaq group contribution revision and extension 2", iec. process des. dev., vol. 21, pp. (118). 11. soave, g., (1993), "application of eos and the theory of group solutions to phase equilibrium prediction", fluid phase equilibrium, vol.47, pp. (189). 12. marc, j. assael. martin trusler, j. p.: thomas f. tsolakis, (1996), "thermophysical properties of fluids", published by icp, london. 13. shuzo ohe, (1989), "vle data", physical data science 37, published by elsevier, tokyo, japan. تطوير طريقة جديدة لربط و استحصال نقاط توازن البخار مع السائل عند درجة حرارة ثابتة للخالئط الثنائية من قبل د. فينوس مجيد بقال باشى التميمي طريقة جديدة لحساب توازن البخار مع السائل ايجاد طريقة لحساب توازن البخار و السائل دائما تحتاج. قدمت وكانت باسلوب سهل جدا" وأعطت نتائج جيدة جدا" مقارنة مع الطرق التي أستخدمت سابقا" بدون الحاجة الى اي خاصية فيزياوية ألي من المركبات . ما عدا الحاجة الى ثابتان اثنان فقط يمثالن ذلك الخليط. باألضافة الى انه ممكن تطبيقها لحساب توازن البخار مع السائل ألي خليط ثنائي بأي قطبية و من أي مجموعة على هذه الطريقة عكس الطرق السابقة. ما عدا الخالئط التي تكون مركبات ايزوتروبية. هذه الطريقة قد طورت لتشمل شكل جديد ين فقط. وقد تم تطبيق بحيث تغطي مدى من درجات الحرارة. هذا المدى اليحتاج خالل التطبيق سوى ثابت وازن مختبرية وكانت النتائج نقطة ت 2211مركب عند درجات حرارة مختلفة لـ 65المعادلة المقترحة على مزيج ثنائي عند درجات حرارة مختلفة واعطت نتائج جيدة جدا". 21جدا". بينما تطوير الطريقة طبق على جيدة available online at https://ijcpe.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.19 no.2 (june 2018) 9 – 13 issn: 1997-4884 corresponding authors: wafa al kattan , email: na, sameer n. al jawad, email: d.sameer@yahoo.com, haider ashour jomaah, email: haiderashour@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial-noderivatives 4.0 international license cluster analysis approach to identify rock type in tertiary reservoir of khabaz oil field case study wafa al kattan a , sameer n. al jawad b and haider ashour jomaah c a petroleum engineering department/ college of engineering/ university of baghdad b ministry of oil/ department of reservoir and field development c college of engineering/ university of baghdad abstract rock type identification is very important task in reservoir characterization in order to constrict robust reservoir models. there are several approaches have been introduced to define the rock type in reservoirs and each approach should relate the geological and petrophysical properties, such that each rock type is proportional to a unique hydraulic flow unit. a hydraulic flow unit is a reservoir zone that is laterally and vertically has similar flow and bedding characteristics. according to effect of rock type in reservoir performance, many empirical and statistical approaches introduced. in this paper cluster analysis technique is used to identify the rock groups in tertiary reservoir for khabaz oil field by analyses variation of petrophysical properties data that predicted by analysis of well log measurements. in tertiary reservoir four groups identified by cluster analysis technique, were each group was internally similar in petrophysical properties and different from others groups. keywords: rock identification, khabaz oil field accepted on 23/5/2016 1introduction cluster analysis is a multivariate approaches which aims to distribute a sample of subjects of a set variable measured into a different number of groups where similar subjects are placed in the same group ‎[1]. well log cluster analysis is process aim to look for similarities and dissimilarities between data points in the multivariate space of logs, in order to distribute them into classes called electrofacies suzan et al 2010. an electrofacies is a unique set of log responses that characterizes the rocks physical properties and fluids contained in the volume that investigated by the logging tools ‎[2]. there are different methods that can be used to make a cluster analysis; these methods can be classified as follows ‎[1] 1.1. hierarchical approach in this approach there are different methods which clusters should be joined at each stage. the main methods are summarized as: a. nearest neighbor method in this method the distance between two clusters between the two closest members, or neighbors. b. furthest neighbor method in this case the distance between two clusters is defined to be the maximum distance between members. c. average method the distance between two clusters is calculated as the average distance between all pairs of subjects in the two clusters. the distance between two subjects can be measured by euclidean distance as following ‎[1]. √∑ (1) 1.2. non-hierarchical or k-means clustering methods in these methods desired in advance the number of clusters to specify and the best solution is chosen. when large data sets are involved, non-hierarchical cluster analysis tends to be used it allows subjects to move from one cluster to another so, sometimes preferred because this isn't possible in hierarchical cluster analysis. there are two disadvantages of k-mean cluster analysis first know how many clusters likely to have often difficult and therefore the analysis may have to be repeated several times and second it very sensitive to the choice of initial cluster ‎[1]. the clustering proses based on two stages. firstly, the well log data is classified into manageable data clusters so that the number of clusters should be enough to cover all the different data ranges that can be detect on the logs w. al kattan, s. n. al jawad and h. a. jomaah / iraqi journal of chemical and petroleum engineering91,2 (2018) 913 01 data .the reasonable number of clusters for most data sets are between 15 to 20 clusters. the second step based on takes these 15 to 20 clusters and group them into a manageable number of rocks types and reducing the data to 4 to 5 homogenous groups ‎[3]. 2main section khabaz oil field is one of iraqi field with multiple pay zones similar to most of the northern iraqi carbonate oil fields. it's located to north west of kirkuk city and far away about 12 km from kirkuk city center ‎[4]. this paper is developed by depending on data from eleven wells was selected for this study. interactive petrophysics program 3.5 used to apply cluster analysis in order identify rock type for tertiary reservoir in khabaz field. sonic (dt), bulk density (rhob), water saturation (sw), and effective porosity (phie) and predicted permeability(k) logs for the eleven studied wells, were used as input data for cluster analysis, 20 clusters assume to cover all data variation. k-mean statistical technique used to seed input data in to given clusters by assume initial guess mean value for each cluster for each input loge data and then try to minimize sum of squares deference within cluster between data points and cluster mean value. the 20 cluster consolidated by hierarchal technique which based on compute distance between clusters and merger two closest clusters in distance then return compute the distance between new clusters and re-merge the two new closest clusters .the processes done until all clusters merged in one cluster. consolidating of the clusters into a known number of rock types is easily indicated by cluster randomness plot done by plot random thickness index vs. number of clusters. the randomness is performed on original logs data by calculating the average number of depth levels per cluster which represent the average cluster thickness layer. then the theoretical average random thickness is determined by assuming the clusters to be assigned randomly at each depth level. the randomness index represents the ratio of average cluster thickness to average random cluster thickness ‎[3]. av. thickness = number of depth levels / number of cluster layers (2) – (3) where, pi is the proportion of depth levels assigned to the i-th cluster. randomness index = av. thickness / random thickness (4) randomness plot for tertiary reservoir shows four groups can be depend as rocks types by collecting the number heights peaks as shown in the fig. 1. fig. 1. cluster group’s randomness for tertiary reservoir in khabaz field the hierarchal technique shows merging process of rock type in groups distinguished by different colors explained in treediagram as shown in fig. 2. fig. 2. cluster grouping tree diagram for tertiary reservoir in khabaz field table 1. cluster analysis results for each rock type clusters phie sw dt k rhobc cluster groups points mean std. dev. mean std. dev. mean std. dev. mean std. dev. mean std. dev. 1 1 343 0.24 0.03 0.35 0.21 74.30 5.17 296.64 61.22 2.29 0.08 2 1 421 0.22 0.02 0.16 0.09 77.19 4.11 182.19 34.16 2.31 0.04 3 1 640 0.20 0.03 0.36 0.16 69.13 2.88 147.90 31.49 2.40 0.04 4 1 677 0.18 0.02 0.20 0.10 72.66 3.62 85.00 23.52 2.39 0.05 5 2 696 0.15 0.03 0.22 0.10 68.25 2.86 13.98 11.98 2.45 0.03 6 3 194 0.19 0.04 0.86 0.14 74.13 4.43 45.79 41.95 2.44 0.06 7 2 586 0.08 0.02 0.40 0.14 65.55 2.80 2.28 4.01 2.52 0.04 8 2 678 0.17 0.04 0.51 0.10 66.05 2.59 22.18 20.60 2.49 0.04 9 2 437 0.14 0.04 0.22 0.11 58.88 3.46 23.20 20.54 2.46 0.06 10 3 585 0.16 0.03 0.88 0.11 67.15 2.86 9.44 9.61 2.45 0.04 11 3 517 0.07 0.03 0.95 0.09 68.69 3.14 0.49 1.09 2.55 0.05 12 2 705 0.12 0.02 0.50 0.14 60.38 2.16 7.82 9.43 2.56 0.03 13 2 692 0.06 0.02 0.42 0.15 55.64 2.74 0.80 3.07 2.60 0.05 14 3 940 0.12 0.02 0.95 0.08 63.97 2.28 4.21 5.22 2.53 0.03 15 4 1134 0.08 0.02 0.98 0.06 61.45 1.61 0.38 1.20 2.60 0.03 16 4 615 0.02 0.02 0.99 0.06 62.04 2.43 0.01 0.01 2.63 0.05 17 4 810 0.08 0.02 0.95 0.09 56.82 1.92 0.48 2.19 2.58 0.04 18 4 1478 0.05 0.02 0.99 0.05 57.92 1.58 0.03 0.07 2.65 0.03 19 4 816 0.02 0.02 0.98 0.07 53.06 1.97 0.02 0.07 2.68 0.04 20 4 207 0.00 0.02 1.00 0.00 54.65 3.28 0.01 0.01 2.83 0.05 k-mean clusters results w. al kattan, s. n. al jawad and h. a. jomaah / iraqi journal of chemical and petroleum engineering91,2 (2018) 913 00 the quality of four rocks types identified from k-mean values of petrophysical properties which are used as input parameter for cluster analysis that tabulated in the table 1. according to k-mean values for each cluster within rock type groups each group given grad as: best quality rock type good quality rock type moderate quality rock type bad quality rock type final graphical of cluster analysis for selected wells in this paper explained in the fig. 3 fig. 3. the final graphical result of clustering analysis w. al kattan, s. n. al jawad and h. a. jomaah / iraqi journal of chemical and petroleum engineering91,2 (2018) 913 01 fig. 4. rock type for kz-2 by cluster analysis method fig. 5. rock type for kz-3 by cluster analysis method kz-3scale : 1 : 1300 depth (2230.05m 2460.m) 04/08/2015 18:28db : ip (3) depth depth (m) tops tops saturation sw ((%)) 1. 0. porosity phi ((%)) 0.5 0. rock rock type 1 rock type 2 rock type3 rock type 4 matrix phi ((%)) 1. 0. clay porosity matrix 2250 2275 2300 2325 2350 2375 2400 2425 2450 j e r ib e u n it a u n it a " u n it b u n it b e u n it e w. al kattan, s. n. al jawad and h. a. jomaah / iraqi journal of chemical and petroleum engineering91,2 (2018) 913 02 3conclusion cluster analysis is a simple method can be used to identify rock type fore reservoir depending on log data. 1cluster analysis of log data for wells that penetrated tertiary reservoir shows that the tertiary reservoir can be divided in four groups as shown in roundness plot. 2plotting rock type in continuous form in selected wells shows that the unit b is the most interested zone in tertiary reservoir for khabaz oil field. references [1] rosie cornish, statistics cluster analysis, mathematic learning support center, 2007. [2] t. euzen, well log cluster analyses and electrofacies classification: probabilistic approach for integration log with mineralogical data. geoconvention 2012, [3] interactive petrophysics ipv3.5 user manual 2008. [4] integrated reservoir study for tertiary reservoir in khabaz field 1989, north oil company – ministry of oil. http://www.searchanddiscovery.com/pdfz/documents/2014/41277euzen/ndx_euzen.pdf.html http://www.searchanddiscovery.com/pdfz/documents/2014/41277euzen/ndx_euzen.pdf.html http://www.searchanddiscovery.com/pdfz/documents/2014/41277euzen/ndx_euzen.pdf.html iraqi journal of chemical and petroleum engineering vol.16 no.3 (september 2015) 1122 issn: 1997-4884 extraction of essential oils from citrus by-products using microwave steam distillation ibtehal k. shakir and sarah j. salih chemical engineering department – college of engineering – university of baghdad abstract the main objectives of this research is to extract essential oil from: orange ( citrus sinensis), lemon( citrus limon) and mandarin( citrus reticulata) peels by two methods: steam distillation (sd) and microwave assisted steam distillation (masd), study the effect of extraction conditions (weight of the sample, extraction time, and microwave power, citrus peel type) on oil yield and compare the results of the two methods, the resulting essential oil was analyzed by gas chromatography (gc). essential oils are highly concentrated substances used for their flavor and therapeutic or odoriferous properties, in a wide selection of products such as foods, medicines and cosmetics. extraction of essential oil is one of the most time and effort consuming process. microwave-assisted extraction is a green technique for the extraction of natural products. (masd) was better than (sd) in terms of rapidity, energy saving and yield. (masd) gave higher yield than (sd) with shorter extraction time, yield of orange oil extracted by (masd) was (1.150%) in (35min.) compared to (1.095%) in (45min.) by (sd) process, same results obtained for lemon and mandarin. the optimal microwave power was (135w) gave oil yield: (1.150%, 1.115%, 0.940%) for orange, lemon and mandarin respectively, (masd) increased extraction temperature in short time and to a higher level compared to (sd). the optimal weight was (398.56gm) gave yield in (sd): (1.095%) and masd (1.091%) for orange oil, same results obtained for lemon and mandarin. the best citrus peel type which gave the highest yield was orange followed by lemon then mandarin in both processes. limonene is the most abundant component in citrus essential oil, (gc) analysis showed that (sd) was more convenient to give high amount of limonene because of the graduate temperature rise, while in microwave extraction exposure to low microwave key words: essential oil, extraction, steam distillation, microwave assisted steam distillation, orange, lemon, mandarin, citrus peels, yield introduction essential oils are volatile natural, complex mixtures comprising many unique compounds [1]. essential oils extracted from several plant organs including flowers, leaves, twigs, seeds, fruits, roots, wood or bark are valuable natural products [2]. nowadays, people worldwide are looking towards natural base products since there are no side effects when taken accordingly. furthermore, there is also an interest in iraqi journal of chemical and petroleum engineering university of baghdad college of engineering extraction of essential oils from citrus by-products using microwave steam distillation 12 ijcpe vol.16 no.3 (sept. 2015) -available online at: www.iasj.net the production of functional, high value, natural products without chemical modification and residues of solvents or additives [3] , for these reasons essential oils are used as raw materials for many products including food flavorings, additives, flavoring agents used in the cigarette industry and in the compounding of cosmetics and perfumes [2].they are used also in air fresheners and deodorizers as well as in all branches of medicine such as: pharmacy, balneology, massage and homeopathy [3]. citrus is the largest fruit crop in the world (100 million cubic tons per year) and the orange account for 60% [4]. the remaining orange peel account for approximately 45% of the total bulk [5], represent a problem for management, pollution, and environmental issues, due to microbial spoilage. thus new aspects concerning the use of these by-products for further exploitation on the production of food additives or supplements with high nutritional value and economically attractive have gained increasingly interest [6]. the traditional method to extract essential oils from the citrus peels is by cold pressing. distillation is also used in some countries as an economical way to recover the oils, with a better yield of 0.21% vs. 0.05% for cold pressing [7]. nowadays, many novel techniques for the extraction of essential oils that could lead to more compact, safer, more efficient, energy saving, and sustainable extraction processes, including ultrasound-assisted extraction (uae), microwave-assisted extraction (mae), supercritical fluid extraction (sfe) and accelerated solvent extraction (ase) have become relatively mature and widely accepted by industries [8]. microwave is intrinsically one type of electromagnetic waves with frequency ranging from 300mhz to 300ghz, which can penetrate biomaterials and interact with polar molecules such as water in the biomaterials to create heat [9]. due to it's high selectivity, microwave heating is capable of expanding and rupturing of cell walls followed by the liberation of chemicals into surrounding solvent in short time [10]. sahraoui et al. [11] extracted essential oil from citrus by-products (orange peels) with a new process, microwave steam distillation (msd). compared to the conventional steam distillation (sd), the results obtained confirm the effectiveness of this new technique, which allows substantial savings in term of extraction time and energy. msd highly accelerated the extraction process, without causing changes in the volatile oil composition. msd offered important advantages like shorter extraction time, with msd 6 min provides yields comparable to those obtained after 2 h by sd, which is the reference method in essential oil isolation. the values of yield obtained are respectively 5.43 ± 0.03% for msd and 5.45 ± 0.04% for sd. msd offered cleaner features and provided an essential oil with better sensory properties (better reproduction of natural fresh fruit aroma of the citrus essential oil) at optimized power (500 w). cassel et al. [12] used rectification extraction (re) to isolate essential oils from chinese herbs, re and steam distillation (sd) techniques were applied to isolate essential oils from three typical chinese herbs bupleurum, pogostemon cablin (blanco) benth (pcb), pericarpium citri reticulatae (pcr). the experiment shows that sd technique cannot get volatile oils and only aromatic water from bupleurum but re can prepare both. re technique increases 10% oil yield of pcb and 20% of pcr compared with sd, ibtehal k. shakir and sarah j. salih -available online at: www.iasj.net ijcpe vol.16 no.3 (sept. 2015) 13 respectively. therefore, re would be more effective and suitable for enriching volatile oils from plants or herbs in which volatile oils are watersoluble and with low-content. therefore, re can significantly shorten the operation time of extracting volatile constituents of herbs such as chuanxiong and bupleurum, and reduce energy consumption relatively during isolating process. the common components in the oils prepared by sd and re, occupy more than 91% of the volatile oil samples. compared with sd, re technology not only increases volatile oil yield, but also barely changes the constituents and compositions of volatile oils. farhat et al. [13] microwave steam diffusion (msd) was developed as a cleaner and new process design and operation for isolation of essentials oils from dry lavender flowers and was compared to conventional steam diffusion (sd). the essential oils extracted by msd for 3 min were quantitatively (yield) and qualitatively (aromatic profile) similar to those obtained by conventional steam diffusion for 20 min. in addition, an optimal operating steam flow rate of 25 g min −1 and microwave power 200 w were found to ensure complete extraction yield with reduced extraction time. msd was better than sd in terms of energy saving, cleanliness and reduced waste water. lucchesi etal. [14] used two different extraction methods for a comparative study of algerian myrtle leaf essential oils: solvent-freemicrowave-extraction (sfme) and conventional hydrodistillation (hd). essential oils analyzed by gc and gcms presented 51 components constituting 97.71 and 97.39% of the total oils, respectively. solvent-freemicrowave-extract essential oils sfme-eo were richer in oxygenated compounds. several advantages with sfme were observed: faster kinetics and higher efficiency with similar yields: 0.32% dry basis, in 30 min as against 180 min for hd. ginies et al. [15] used a total of eight extraction techniques ranging from conventional methods (hydrodistillation (hd), steam distillation (sd), turbohydrodistillation (thd)), through innovative techniques (ultrasound assisted extraction (ussd) and finishing with microwave assisted extraction techniques such as in situ microwave-generated hydrodistillation (ismh), microwave steam distillation (msd), microwave hydrodiffusion and gravity (mhg), and microwave steam diffusion (msdf)) to extract essential oil from lavandin flowers and their results were compared. the method which gave the best results was the microwave hydrodiffusion and gravity (mhg), it gave the maximum yield (5.4%) in only 15 min (120 min for sd) and consumed 1.3 kwh (against 8.06 kwh for sd). the essential oil obtained was of excellent quality (low degradation) and natural odor (similar smell to the original lavender). vieira et al. [16] studied supercritical carbon dioxide extraction of essential oil from thymus vulgaris leaves in the florys s.p.a. laboratory at 40 °c and 20 mpa for three different particle sizes and three different flow rates. a mathematical model, proposed in the literature, based on the local adsorption equilibrium of essential oil on lipid in leaves was used to calculate internal and external mass transfer resistances. the adsorption equilibrium constant was fitted to these experimental data, and preliminary results suggested that the extraction process is controlled by mass transfer resistance due to intraparticle diffusion. in this study, microwave steam distillation (msd) apparatus has been extraction of essential oils from citrus by-products using microwave steam distillation 14 ijcpe vol.16 no.3 (sept. 2015) -available online at: www.iasj.net used for extraction of essential oil from three types of fresh citrus peels: orange ( citrus sinensis), lemon( citrus limon), and mandarin (citrus reticulate). comparisons have been made to conventional steam distillation (sd) in terms of extraction time, yield, weight of the sample, and composition of essential oil. the essential oils were analyzed by gas chromatography to determine the concentration of limonene in each produced sample for qualitative study. experimental work collection of plant material citrus fresh fruits: orange (citrus sinensis), lemon (citrus limon), mandarin (citrus reticulata) brought from local markets. each type of citrus fruit was washed and peeled separately. the fresh peels were grated using an electrical grater that results small particles of the peels. they were divided into three groups having three different weights: (398.56gm, 281.8gm, and 116.76gm ) experimental procedure 1extraction of essential oil by microwave assisted steam distillation (masd) in microwave assisted steam distillation (masd) unit an pyrex flask which contained boiled distilled water generating steam and a condenser placed outside the microwave oven are connected to a cartridge containing grated citrus peels via pyrex connecting tubes. the condenser is connected to a receiving flask which is preferably a separating funnel to enable the continuously collection of condensate essential oil and water. this system presents the advantage that the cartridge containing plant materials can be easily and quickly replaced and cleaned after each cycle of extraction as shown in fig.1. the cartridge containing the required weight for each run ( 398.56gm for full flask, 281.8gm for half full, and 116.76gm the quarter of flask ) of citrus peels is subjected to microwave heating and vapor which cross the plant material. the probe of the sensor was placed on the extraction vessel in order to record temperature, as the steam rises up to the grated peels charged with the essential oil on it's way to the condenser with the first drop of condensate flows in the separation funnel the microwave irradiation power is switched on. fig.1, schematic diagram of the experimental extraction unit of microwave assisted steam distillation microwave energy can interact selectively with the free water molecules contained in plant cells and causes localized heating, the final effect is a sudden non-uniform rise in temperature and dramatic expansion in volume with in plant cells. the cell walls cannot stand with such a high internal pressure leading to cell wall distraction and allowing the substance inside of plant cells to flow freely ibtehal k. shakir and sarah j. salih -available online at: www.iasj.net ijcpe vol.16 no.3 (sept. 2015) 15 toward surrounding steam the resulting distillate is collected in a separation funnel. the extraction was continued until no more essential oil was obtained. 2extraction of essential oil by steam distillation (sd) for a rigorous comparison, the same glassware and same operating conditions have been used for conventional steam distillation. the vapor produced by the boiled distilled water crosses the plant, charged with essential oil and then passes through the condenser to a receiving flask [17]. 3separation of essential oil from water in separation funnel the essential oil will float on top of the hydrosol (distilled water component) also called floral water and may be separated off. due to immiscibility of the oil and water at room temperature for essential oil is lighter than water, citrus essential oil has a density in the limits of 0.8085gm/cm 3 while density of water is 1gm/cm 3 . water layer was carefully run out from the bottom of the funnel by opening the tap leaving the oil, which was dried over anhydrous sodium sulphate and kept in a dark glass vial at temperature of 4 °c for further analysis. the yield percent was calculated by using the following relationship: yield= 100% parameters studied for both extraction methods (masd and sd)for three types of citrus peels; orange (citrus sinensis), lemon (citrus limon), mandarin (citrus reticulata):  extraction time  extraction yield  microwave irradiation power:( 135w, 265w, 445w)  weight of grated peels(398.56gm, 281.8gm, and 116.76gm ) result and discussion 1effect of extraction time essential oil was extracted from two types of citrus peels orange (citrus sinensis), and mandarin (citrus reticulata) each having three weights : ( 398.56 gm, 281.8 gm, 116.76 gm), at (sd) process and (masd) process exposing to (265w). extraction time was different for these three weights and extraction yield was studied until equilibrium was reached. fig. (2) & (3) show oil yield in (sd) process: the weights(398.56gm, 281.8gm) had longer time than (116.76gm); at these two weights the yield of orange oil was: (1.095%, 0.860%) with extraction times: (45min., 50min.) respectively, while the weight(116.76gm) gave yield for orange oil: (0.969%) with extraction time(35min). mandarin had longer extraction time than orange with lower yield since mandarin peel is so tender not much oil sacks or glands contained in peels, oil yield for weight(398.56gm) after (75min.) extraction time was (0.707%), for weight(281.8gm) after (55min.) extraction time the yield was (0.702%) and for weight(116.76gm) after(50min.) extraction time the yield was(0.848%). extraction of essential oils from citrus by-products using microwave steam distillation 16 ijcpe vol.16 no.3 (sept. 2015) -available online at: www.iasj.net fig. 2, effect of extraction time on yield of orange oil extracted by (sd) for the three weights fig. 3, effect of extraction time on yield of mandarin oil extracted by (sd) for the three weights fig. (4) & (5) show oil yield in (masd) process: the weights(398.56gm, 281.8gm) both had extraction time (35min.), for orange the yield for these two weights was: (1.058%, 0.588%), while for (116.76gm) after (20min.) extraction time the yield was: (0.516%). for mandarin having weight (398.56gm) after (35min.) extraction time the yield was: (0.846%), for weight (281.8gm) after (30min.) extraction time the yield was: (0.558%), and for weight (116.76gm) after (15min.) extraction time the yield was: (0.385%). by analyzing data in figures above the essential oil extracted by (sd) process had longer time and higher yield than oil extracted by (masd) process after exposing to microwave power (265w) which delivered heat higher than (sd) process and that affected oil yield, since citrus essential oil is highly sensitive to heat applied by microwave irradiation which is higher than heat applied by (sd) [11]. it can be notes from these figures that extraction of oil increased with time for the two methods: (sd), (masd) but, the yield of oil extracted by (masd) reached equilibrium in shorter time than that of (sd) with differences in yields. the ability of (masd) method to accelerate extraction of essential oil is by rapid increase in temperature causing a dramatic expansion in volume within plant cells, the cell walls cannot with stand such high internal pressure resulting with rupture of the cells and glands of plant material more rapidly than conventional (sd) [10], these results are in agreement with results obtained by sahraoui et al. (2011) [11]. fig. 4, effect of extraction time on yield of orange oil extracted by (masd) for the three weights. 0 0.2 0.4 0.6 0.8 1 1.2 0 20 40 60 % o il y ie ld time( min.) 398.56g m 281.8gm 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 0 20 40 60 80 % o il y ie ld time( min.) 398.56g m 281.8g m 0 0.2 0.4 0.6 0.8 1 1.2 0 20 40 % o il y ie ld time( min.) 398.56gm 281.8gm 116.76gm ibtehal k. shakir and sarah j. salih -available online at: www.iasj.net ijcpe vol.16 no.3 (sept. 2015) 17 fig.5 effect of extraction time on yield of mandarin oil extracted by (masd) for the three weights. 2effect of grated peels weight fig.(2) & (3) show that for (sd) process since the extraction vessel is spherical shaped the action of steam was affected by the content of grated peels in the vessel. for the weight (398.56gm) the vessel was fully loaded and for weight (281.8gm) the vessel was half loaded when the steam passes from the bottom of vessel through the grated peels toward the top few amounts of peels at the side were far from the action of steam and extraction was at the upper and lower layers of peels where the steam moved freely. it can be notes that (116.76gm) weight had the least space in extraction vessel and it was totally exposed to steam where it moved freely charged with essential oil, for this reason the weight (116.76gm) subjected to (sd) process gave yield (0.969%), while for mandarin with weight(116.76gm) after (50min.) the yield was (0.848%). in (masd) process oil yield increases with increasing the weight exposed to microwave power as shown in fig. (4) & (5). for orange peels having weight(116.76gm) exposed to microwave power (265w) for (20min.) the yield was (0.532%), while for weight(281.8gm) exposed to same power for (35min.) the yield was (0.606%) and for weight (398.56gm) under same conditions the yield was (1.091%). for the weight(398.56gm) the yield obtained by (sd) and (masd) processes were close no striking differences found but the weights (281.8gm, 116.76gm) their yields obtained by (sd) were higher than (masd) this means that microwave irradiation is inefficient with low weights, for orange having weights(281.8gm, 116.76gm) the oil yield extracted by (sd) was: (0.860%, 0.969%) while for (masd) for these weights the yield was: (0.606%, 0.532%). (masd) method need the presence of water as "in situ" water in the plant material tissue, it is already known that only water in a liquid state absorbs microwaves but steam or even ice do not absorb microwaves because in the gas state the molecules are too far each other to have frictions, and in solid state the molecules are not free to move and rotate to heat [13] , for this reason (masd) process is more efficient with high weights of peels for their high water content in tissues and the yield decreases with low weights for their low water content in their tissues. these results are in agreement with results obtained by margosan et al. (2001) [18]. 3effect of microwave power according to previous research reports, essential oil yield differs in different microwave powers therefore; the effect of microwave power was studied. in principle, higher electromagnetic energy absorption could result in more power dissipated inside the plant material and generating more effective molecular movement and heating, leading to an improvement in the extraction efficiency [10]. 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 0 20 40 % o il y ie ld time( min.) 398.56gm 281.8gm 116.76gm extraction of essential oils from citrus by-products using microwave steam distillation 18 ijcpe vol.16 no.3 (sept. 2015) -available online at: www.iasj.net as shown in fig. (6) & (7) essential oil was extracted from three types of citrus peels each type having a weight( 398.56gm), exposed to microwave powers:( 135w, 265w, 445w) with exposure time to irradiation power:(5min., 10min.). in this method the yield of essential oil was affected by the amount of heat applied by microwave power. at the beginning of extraction process oil yield increased by increasing microwave power from (135w) to (265w) for orange the yield was after (5min.) of exposure to these powers: (0.194%, 0.526%) respectively and after (10min.) of exposure to these powers the yield increased: (0.701%, 0.818%) respectively, moreover increasing in extraction time the yield increases slightly by power (265w) in comparison with power (135w), the yield was increasing until the extraction ended after (35min.) with yield: (1.150%, 1.091%) for powers: (135w, 265w) respectively; same results was obtained for mandarin. when the power was raised to (445w) the yield was lower than yield obtained by the powers (135w, 265w) from the beginning to the end of extraction process. citrus essential oils are highly sensitive to the variation of processing temperature result from high microwave power (265w, 445w) , they can cause thermal degradation to essential oil, this fact explain why oil yield was lower for high microwave powers (265w, 445w). so in order to avoid that it would be better to use low microwave power (135w) for complete recovery of essential oil, these results are in agreement with results obtained by chun-hui et al.(2012) [19]. fig. 6, effect of microwave power on yield of orange oil extracted by (masd) fig. 7, effect of microwave power on mandarin oil extracted by (masd) 4effect of citrus peel type essential oil is present in citrus peels in oil sacks and glands which are located at different depths in citrus peel, the amount of this oil differ from citrus type to another, also conditions of extraction process play role in the complete recovery of essential oil [20]. it can be notes from fig. (8) & (9) that for orange and lemon with weight (398.56gm) the yields were close for (sd) with extraction time (45min.): (1.095%, 1.061%) respectively, and they were higher than mandarin: 0 0.2 0.4 0.6 0.8 1 1.2 1.4 0 10 20 30 40 % o il y ie ld time( min.) 135w 265w 445w 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 50 100 % o il y ie ld time( min.) 135 w 265 w ibtehal k. shakir and sarah j. salih -available online at: www.iasj.net ijcpe vol.16 no.3 (sept. 2015) 19 (0.707%) with extraction time (75min.) while for (masd) the yield of orange and lemon after (35min.) extraction time was: (1.150%, 1.115%) while for mandarin after (60min.) the yield was (0.940%). for both methods the yield of orange and lemon were close same and were higher than that for mandarin, where oil yield for mandarin had longer extraction time and gave lower yield than orange and lemon in both methods, the reason for that is the nature of mandarin peel tissue, it do not have much oil glands contained in peels to be ruptured by steam or microwaves to release the oil [18], these results are in agreement with results obtained by meklati et al. (2007) [21]. fig. 8, effect of citrus type on yield of essential oil extracted by (sd) from citrus peel weight (398.56gm) fig. 9, effect of citrus type on yield of essential oil extracted by (masd) from citrus peel weight (398.56gm) 5extraction kinetics as shown in fig. (10) & (11) the (masd) process can give essential oil with higher yield and better quality in shorter extraction time than (sd) process when the power is low, the use of longer exposure time would be helpful for the complete recovery of essential oil when microwave power is not too high to avoid thermal degradation of essential oil. by analyzing these figures two phases are observed in (masd) yield the first step is represented by a rapid increase in the yield followed by a second step corresponding to a slight increase until reach the end of extraction, the rapid increase in the yield during the first step suggests that the essential oil is easily accessible by the steam due to action of microwaves in rupturing oil glands while the steam passes charged with essential oil. for (sd) method three phases are observed the first step is represented by an increasing line which characterizes the first quantities of extracted essential oil this phase is followed by second increasing line representing the diffusion of essential oil from the middle layers of citrus peels, the third 0 0.2 0.4 0.6 0.8 1 1.2 0 20 40 60 80 % o il y ie ld time( min.) orange lemon 0 0.2 0.4 0.6 0.8 1 1.2 1.4 0 20 40 60 80 % o il y ie ld time( min.) orange, masd lemon, masd extraction of essential oils from citrus by-products using microwave steam distillation 20 ijcpe vol.16 no.3 (sept. 2015) -available online at: www.iasj.net phase corresponds to a horizontal line which marks end of extraction, these results are in agreement with results obtained by farhat et al. (2009) [13]. fig. 10, yield of orange oil extracted by (sd) and (masd) as function of extraction time fig. 11, yield of mandarin oil extracted by (sd) and (masd) as function of extraction time 6gas chromatography (gc) chemical identification of essential oil was investigated by gas chromatography equipped with (fid) detector (backard, 438a, u.s.a). essential oil extracted from (orange, lemon, mandarin) peels is mainly composed of limonene, linalool, citronellal, nerol, geranial etc. among many other components. the relative amounts of these components varied according to type of citrus peel and conditions of extraction process. from table (1) for mandarin oil the amount of limonene extracted by (masd) in low microwave power with long extraction time was (84.3891% at 135w in 60min.), while for (sd) it was (83.0271% in 75min.) and decreased with increasing microwave power, for orange oil it was (80.9661% at 265w in 35min.) while for (sd) it was (83.2189% in 45min.). for orange and lemon when microwave power was increased the amount of limonene decreased and was lower than that extracted by (sd). so when using microwave power for extraction the best condition is exposure to low microwave power for long time. the influence of microwave energy on extraction is strictly thermal and it highly accelerated extraction process, phenomenon which was already described by chemat et al. (2006) [22]. table 1, amount of limonene extracted from citrus peels by (sd), (masd) and conditions of extraction. citrus peel limonene content% [23] amount of limonene % for (sd) amount of limonene % for (masd) mandarin 94.62% 83.0271 84.3891 orange 91.40% 83.2189 80.9661 lemon 65.44% 65.2867 59.156 conclusions according to the results obtained from this study, the following conclusions are obtained: 0 0.2 0.4 0.6 0.8 1 1.2 1.4 0 20 40 60 % o il y ie ld time( min.) sd, orange masd(135w), orange 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 20 40 60 80 % o il y ie ld time (min.) sd, mandarin ibtehal k. shakir and sarah j. salih -available online at: www.iasj.net ijcpe vol.16 no.3 (sept. 2015) 21 1the extraction yield of oil increased with time for the two methods: (sd), (masd) but, the yield of oil extracted by (masd) reached equilibrium in shorter time than that of (sd). 2the weight (116.76gm) subjected to (sd) process: in orange and lemon gave yield (0.969%, 0.939%) higher than weight (281.8gm) which gave yield (0.860%, 0.834%) respectively, while for mandarin this weight gave yield (0.848%) higher than the other weights (398.56gm, 281.8gm) which gave yields (0.707%, 0.648%) respectively. 3it would be better to use low microwave power (135w) for complete recovery of essential oil and higher microwave power (265w) can be used but for short exposure time to avoid thermal degradation of essential oil. 4oil yield for mandarin had longer extraction time and gave lower yield than orange and lemon in both methods. 5the amount of limonene extracted by (masd) was higher than that extracted by (sd) for mandarin. references 1k. bajpaiv, a. sharma, h. baekk, (2013), "antibacterial mode of action of fruit essential oil, affecting membrane permeability and surface characteristics of foodborne pathogens", food control, vol.32, pp.582-590. 2h.c.baserk, g.buchbauer, (2010), "handbook of essential oils: science technology and applications", boca raton, fl:crc press, 2 nd edition, pp. 2243-2245. 3nurul azlina binti mohamed, (2005), "study on important parameters affecting the hydrodistillation for ginger oil production", m.sc. thesis, chemical engineering, university of malaysia. 4v. oreopoulou, c. tzia, (2006), "utilization of plant by-products for the recovery of proteins, dietary fibers, antioxidants and colorants", utilization of by-products & treatment of waste in the food industry, springer, vol. 8, pp. 477493. 5s. yeoh, j. shi, t. a. g. langrish, (2008), "comparisons between different techniques for water-based extraction of pectin from orange peels", desalination, vol. 218, pp. 229-237. 6r. j. braddock, (1995), "byproducts of citrus fruits",food technology, vol. 49, pp. 74-77. 7m. a. ferhat, b. y. meklati, j. smadja, f. chemat, (2006), "an improved microwave clevenger apparatus for distillation of essential oils from orange peel", journal of chromatography a, vol. (1112), pp.121-126. 8chen qun, (2011), "the effect of microwave irradiation on the structure of selected plant tissues", ph.d. thesis, department of applied biology and chemical technology, the hong kong polytechnic university. 9v. mandal, y. mohan, s. hemalatha, (2007), "microwave assisted extraction-an innovative and promising extraction tool for medicinal plant research", journal of chromatography a, vol. (45), pp. 718 10f. chemat, e. esveld, (2001), "microwave superheated boiling of organic liquids: origin, effect and application", chemical engineering technology, vol. (24), pp. 735-744. 11naima sahraoui, maryline abert vian, mohamed el maataoui, farid chemat, (2011), "valorization of citrus by-products using microwave steam distillation (msd)", extraction of essential oils from citrus by-products using microwave steam distillation 22 ijcpe vol.16 no.3 (sept. 2015) -available online at: www.iasj.net innovative food science & emerging technologies, vol.(2), pp.163-170. 12e. cassel, r. m. f. vargas, n. martinez, (2009), "steam distillation modeling for essential oil extraction process", industrial crops and products, vol.(29), pp.171-176. 13asma farhat, christian ginies, mehrez romdhane, farid chemat, (2009), "eco-friendly and cleaner process for isolation of essential oil using microwave energy: experimental and theoretical study", journal of chromatography a, vol.(1216), pp.5077-5085. 14m. e. lucchesi, f. chemat, j. smadja, (2004), "solvent free microwave extraction of essential oils from aromatic herbs: comparison with conventional hydro-distillation ", journal of chromatography a, vol.(1043), pp.323-327. 15christian ginies, giancarlo cravotto, farid chemat, (2013), "a comparison of essential oils obtained from lavanadin via different extraction processes: ultrasound, microwave, turbohydro distillation, steam and hydrodistillation", journal of chromatography a, vol.(1305), pp.41-47. 16s. a. b. vieira, g. m. n. costa, r. garau, (2000), "super critical co2 extraction of essential oils from thymus vulgaris l.", brazilian journal of chemical engineering, vol.(17), pp.104-130. 17sarah j. salih, (2014), " extraction of essential oils from citrus byproducts using microwave steam distillation", msc. thesis, chemical engineering department, college of engineering, university of baghdad. 18d. a. margosan, l. h. aung, w. p. wergin, e. f. erbe, (2001), "the nature of oil gland and it's associated tissues in the pericarp of citrus limon (l.) burn. f. by confocal microscopy ", phytoninternational journal of experimental botany, vol.(15), pp.107-119. 19chun-hui, lei yang, yuangangzu, ting-ting liu, (2012), "optimization of conditions of solvent-free microwave extraction and study on antioxidant capacity of essential oil from schisandra chinensis baill", food chemistry journal, vol.(134), pp.2532-2539. 20napaporn thavanapong, (2006), "the essential oil from peel and flower of citrus maxima", m.sc. thesis, pharmacy of silpakorn university. 21b. y. meklati, m. a. ferhat, (2007), "comparison of different isolation methods of essential oil from citrus fruits: cold pressing, hydro distillation and microwave distillation", flavour and fragrance journal, vol.(22), pp.494-504. 22b. y. meklati, m. a. ferhat, (2007), "comparison of different isolation methods of essential oil from citrus fruits: cold pressing, hydro distillation and microwave distillation", flavour and fragrance journal, vol.(22), pp.494-504. 23http://www.essentialoilproperties. co.za/index.htm. http://www.essentialoilproperties.co.za/index.htm http://www.essentialoilproperties.co.za/index.htm iraqi journal of chemical and petroleum engineering vol.15 no4 (december 2014) 25-35 issn: 1997-4884 removal of so2 over modified activated carbon in fixed bed reactor: i, effect of metal oxide loadings and acid treatment neran k. ibraheem 1 , shahrazad r. raouf 2 , zainab a. naser 3* 1, 2, 3 chemical engineering department, university of technology, baghdad, iraq abstract the removal of so2 from simulated gas stream (so2 + air) in a fixed bed reactor using modified activated carbon (mac) catalysts was investigated. all the experiments were conducted at atmospheric pressure, initial so2 concentration of 2500 ppm and bed temperature of 90 o c. mac was prepared by loading a series of nickel and copper oxides 1, 3, 5, 7, and 10 wt% on ac. in some of the experimental runs, the original activated carbon was pretreated with two different concentrations of nitric acid 10 and 45 wt%. the results showed that the so2 removal efficiency, breakthrough time (τ0.05) and sorption capacity increase with increasing metal oxides loadings up to a value of 7 wt% beyond which the desulfurization performance decreases. the pretreatment of the original ac with hno3 enhanced the removal efficiency of so2. the copper supported catalysts showed higher flue gas desulfurization activity as compared to the nickel supported catalysts. keywords: so2 removal, modified activated carbon, acid treatment, fixed bed reactor, so2 adsorption. introduction sulfur dioxide (so2) is one of the gravest chemical threats to the global environment and considered both primary and secondary pollutant [1, 2]. it emits to the atmosphere from power plants, industry, refining of petroleum, smelting of ores and manufacture of sulfuric acid as primary pollutant [3, 4]. some industrial sources emit h2s, which is oxidized to form h2o and secondary pollutant so2, through the most important oxidizing reaction for h2s with ozone [2]. the famous method for reducing emissions of so2 is flue gas desulfurization (fgd). a large number of fgd processes (regenerable and non-regenerable) have been developed and are expected to play an important role in reducing so2 emission from power plants [5]. the so2 removal by dry-regenerable methods provides an appropriate alternative to control the emissions of so2 from oil-fired power plants [6]. being relatively simple and of low cost, dry adsorption with activated carbon (ac) or other adsorbents for so2 removal is being increasingly employed by most industries [7]. pretreatment of the ac or addition of promoters can significantly affect the dispersion of the active species [8, 9]. wang and lu [10], examined the effects of acid treatments by hcl, hf and hno3 on the properties of ni iraqi journal of chemical and petroleum engineering university of baghdad college of engineering removal of so2 over modified activated carbon in fixed bed reactor: i, effect of metal oxide loadings and acid treatment 26 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net supported ac catalyst. it was found that acid treatment significantly changed the surface chemical properties and enhanced the surface area of the ac. it was believed that the hno3 as an oxidant can also oxidize some complexes producing acidic groups. the increase in surface acidity leads to more homogeneous distribution of nickel salt on ac. tseng and wey [11], found that the surface oxygen groups of the carbon support played a major role in determining the extent and strength of interaction with the metal precursor during catalyst preparation. the dispersion of supported metal is one of the main parameters related to its catalytic activity [12]. it is reported that the so2 adsorption characteristics of active carbons are strongly influenced by the presence of certain transition metal derivatives [13]. some authors have reported that ca +2 and mo +2 ions had the greatest effect on the increase of so2 conversion [14]. it was established that heat treatment of modified ac (impregnated with aqueous solution of (ni(no3)2.6h2o) up to 400 o c leads to additional activation of the samples, which is accompanied by an increase in their adsorption characteristics (surface area). destruction of the texture and decrease in the adsorption characteristics of the samples were observed at 550 o c [15]. while, jiaxiu et al. [16], found the characterization results showed that the ni species on the catalyst (ni/ac, ni content of the catalyst was 0.92%) calcined at 400 o c is ni2o3. after calcination at 550 o c, nio species is formed on the ac. nio and ni coexist on the ni/ac catalyst calcined at 800 o c and only pure ni species is observed after calcination at 1000 o c. this suggested that ni can form different chemical states on the ni/ac catalyst calcined at different temperatures, which can lead to a different desulfurization performance. ni/ac catalysts containing only nio or nio and ni coexisting together exhibit good catalytic activity at low reaction temperature 90 o c. also, it was found that the v2o5 plays little role in so2 adsorption but a main role in the oxidation of so2 [17]. lόpez et al. [18], found that the adsorption profiles of ac, demineralized activated carbon (dac), treatment of ac with hcl-hf-hno3 solutions, and cu supported dac (cu/dac) show a similar behavior for adsorption of so2 but, for the cu/dac sample the so2 adsorption continues for more than 7h, which could indicate that there is a favorable effect of cu which catalyzes the adsorption of so2 on the carbonaceous material, this increases the breakthrough time and the adsorption capacity. the objective of the present study is to investigate the effect of the nio and cuo loadings and the treatment of the original ac with nitric acid on the removal efficiency of so2 from simulated gas stream. experimental work catalyst preparation the modified activated carbon (mac) was prepared by using industrial grade, granular activated carbon obtained from local markets, as a support. the chemical analysis (measured by atomic absorption technique), and the physical properties of the original ac (measured by automated surface area and porosity analyzer, (micromeritics company, usa)) are given in tables 1 and 2 respectively. prior to the impregnation process, ac was sieved to a size of 1 mm and dried in an oven at 110 o c for 4 hours, then it was impregnated with different concentrations of an aqueous solution of (ni(no3)2.6h2o) to give nickel oxide supported ac with different loadings of 1, 3, 5, 7 and 10 neran k. ibraheem, shahrazad r. raouf and zainab a. naser -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 27 wt%. the samples was dried at 110 o c in an oven for 4 hours and then calcined at 400 o c for 4 hours. these catalysts were labeled as 1ni/ac, 3ni/ac, 5ni/ac, 7ni/ac, and 10ni/ac respectively. in some of the experimental runs, the original ac was pretreated with two different concentrations of nitric acid (10 and 45 wt%) and labeled as 10nac and 45nac respectively. using the same method, copper oxide supported ac with different loadings of 1, 3, 5, 7 and 10 wt% were prepared by using an aqueous solution of (cu(no3)2.6h2o) and labeled as 1cu/ac, 3cu/ac, 5cu/ac, 7cu/ac, and 10cu/ac respectively. all the details of the required quantities of chemicals required to prepare the different nio and cuo loadings supported ac catalysts are presented in table 3 and 4. table 1: chemical analysis of ac material wt % material wt % c 92.46 zn +2 0.025 ca +2 2.75 mg +2 3.25 co +2 0.075 mn +2 0.1163 cu +2 0.15 pb +2 0.5125 fe +2 0.0696 po4 -3 0.0183 fe +3 0.325 so4 -2 0.0183 others 0.23 wt% table 2: physical properties of ac test results surface area (m 2 /g) 702 pore volume (cm 3 /g) 0.59 bulk density (g/cm 3 ) 0.72 particle density (g/cm 3 ) 1.91 table 3: details of loadings nio on ac nio (wt %) symbol ac (g) ni(no3)2.6h2o (g / 100 cm 3 h2o) 1 1ni/ac 95.05 4.95 3 3ni/ac 85.14 14.86 5 5ni/ac 75.23 24.77 7 7ni/ac 65.32 34.68 10 10ni/ac 50.45 49.55 table 4: details of loadings cuo on ac cuo (wt %) symbol ac (g) cu(no3)2.3h2o (g / 100 cm 3 h2o) 1 1cu/ac 96.19 3.8 3 3cu/ac 88.6 11.40 5 5cu/ac 80.99 19.01 7 7cu/ac 73.39 26.61 10 10cu/ac 61.99 38.01 chemicals for so2 generation and detection for the generation and detection of so2, sodium sulfite, na2so3 was supplied from merck, germany. sulfuric acid, h2so4, iodine, i2, iodine ampoule, 0.1 n, potassium iodide, ki, starch and sodium thiosulfate ampoule, 0.1 n were analytical grade reagents from bdh, england. experimental rig a schematic diagram of lab scale experimental rig designed for the adsorption of so2 from simulated gas stream (so2+air) is shown in figure 1. the rig consists of three sections: so2 generation section, sorption section and the analysis section. for the generation of so2, a three neck qvf 3 l-flask connected at its upper part to a glass burette 200 ml capacity which contains sulfuric acid was used. 2500 ppm of so2 was generated by dropping specified concentration of sulfuric acid solution into the so2 generation vessel that contained sodium sulfite. the inlet of the generation section is connected to a compressed air source. the test section is a qvf column, 2.54 cm inside diameter and 50 cm long, filled with catalyst to a height of 4 cm. the so2 removal was carried out at 90 o c, 1 bar and 140 /h gas flow rate. the rig was insulated with glass wool to maintain the test section temperature nearly constant. calibrated rotameters were used to measure the gas flow rate. the initial and final weights of the catalyst were measured to determine the total amount of so2 adsorbed. the weight of so2 adsorbed was determined by measuring the residual amount by its quantitative reaction with iodine and titrating excess iodine with sodium thiosulfate. the number  removal of so2 over modified activated carbon in fixed bed reactor: i, effect of metal oxide loadings and acid treatment 28 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net of iodine equivalents is equal to the residual so2 in the trap of the analysis section. fig. 1: schematic diagram of the experimental apparatus. (1) compressor (2) needle valve (3) regulator (4&5) wet and dry bulb thermocouple (6) rotameter1 (7) burette (8) so2 generation vessel (9) rotameter2 (10) utube manometer (11) heater (12) selector switch (13) ac (14) variac (15) temperature controller (16) pressure drop (17) absorption trap (18) bed thermocouple (19) reactor data analysis the total amount of so2 adsorbed (mg/g) was calculated as the ratio of the difference between the initial weight of the catalyst (fresh bed) and the final weight of the catalyst (spent bed) to the initial weight of the catalyst, as shown in equation 1. …(1) the removal efficiency of so2 was calculated as the ratio of so2 concentration that was removed by catalyst to the initial concentration of so2 gas fed to the bed, as in equation 2. ɳ % = *100 …(2) full details of the experiment results and data analysis are given in [19]. results and discussion effect of metal loadings the effect of nickel oxide loadings on so2 sorption capacity and the dynamic so2 removal efficiency before breakthrough point at gas rate of 140 /h, bed temperature of 90 height of 4cm are shown in figures 2 and 3 respectively. the results indicate that the nickel oxide supported ac can significantly improve the desulfurization efficiency of the original ac. figures 4 and 5 show the relation between the breakthrough time (τ0.05) and the sorption capacity with ni/ac loadings respectively. it can be noticed from these figures that the breakthrough time and the so2 sorption capacity increase as the ni loading increases up to a value of 7 wt% beyond which the desulfurization performance decreases. for 7 wt% loaded ac, the breakthrough time and the sorption capacity increased to 165 minutes and 191 mg/g respectively as compared to 38 minutes and 120 mg/g for the original ac. 7ni/ac catalyst exhibited the highest desulfurization activity, this behavior may be attributed to the uniform distribution of the active phase within the support and to the type and degree of interaction reached during the impregnation process. the decrease in desulfurization performance beyond 7 wt% ni may be ascribed to the intimate interaction between nickel nitrate and ac in impregnation step which leads to the occlusion of small amounts of ac in ni derivatives crystallites upon calcination [20].  neran k. ibraheem, shahrazad r. raouf and zainab a. naser -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 29 fig. 2: effect of nio loadings on so2 sorption breakthrough fig. 3: dynamic change of so2 removal efficiency for different nio loadings fig. 4: effect of ni o loadings on breakthrough time fig. 5: sorption capacity of so2 for different nio loadings effect of acid treatment the breakthrough curves and the dynamic so2 removal efficiency of 7ni/ac and 7ni/nac catalysts are presented in figures 6 and 7 respectively. the results indicate that the acid treatment significantly enhanced the so2 removal efficiency, the desulfurization activity of the catalysts is in the following sequence from poor to excellent: 7ni/ac<7ni/10nac< 7ni/45nac, indicating that the increase in concentration of acid treatment results in a more homogeneous distribution of nickel oxide on ac and increase the surface area of catalyst.surface oxygen on carbon consists of inorganic and organic matters. acid treatment mainly removes the inorganic oxides and increases the organic oxygencontaining materials, this removal leaves sites on the carbon surface which can chemisorb oxygen in air and this would result in more oxygen surface complexes which are more acidic [21]. the results that are presented in precedent figures are in agreement with the result obtained by leon and radovic [22], and tseng et al. [23] who proposed that the interaction between metallic precursor and carbon support depends on the amphoteric character of carbon material. at ph > phslurry the acidic removal of so2 over modified activated carbon in fixed bed reactor: i, effect of metal oxide loadings and acid treatment 30 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net groups on the carbon surface will dissociate; the negatively charged surface then attracts and adsorbs cations from the solution; at ph < ph slurry it will attract anions. in other words, if the ph of the impregnation solution is higher than the ph of the aqueous slurry of the support (phslurry), then the adsorption of cations is favored. in this sense, these surface oxygen groups can be considered as the anchoring centers for the metal precursor and its presence should favor higher dispersions. fig. 6: dynamic change in so2 effluent concentration for 7ni/nac catalysts fig. 7: effect of hno3 concentration on so2 breakthrough time for 7ni/nac catalysts figures 8 and 9 indicate that as the acidity of the ac increased the breakthrough time and the sorption capacity increased. the breakthrough time increased from 210 minutes to 285 minutes and the sorption capacity increased from 197 mg/g to 208 mg/g as the concentration of hno3 increased from 10 to 45% for 7ni/nac catalyst. this may be attributed to the increase in surface area as given in table 5. the results also indicate that the surface area of 7ni/45nac is lower than that of 45nac this is mainly due to metal loadings. the better performance of 7ni/45nac as compared to 45nac may be due to the role of ni derivatives on catalytic activity. fig. 8: effect of hno3 concentration on breakthrough time for 7ni/nac catalyst fig. 9: so2 sorption capacity for different hno3 concentration for 7ni/nac catalyst neran k. ibraheem, shahrazad r. raouf and zainab a. naser -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 31 table 5: surface area (m 2 /g) of ac before and after acid treatment sample surface area ac 702 10nac 816 45nac 1010 7ni/10nac 767 7ni/45nac 895 acidic oxygenated surface groups (carboxylic, lactone, carbonyle, phenolic) were determined by fourier transform infrared (ftir, bruker company), the results are shown in figures 10-13. lisovskii et al. [24] clarified that the carbon which contains more oxygenated groups and in which the acidity is higher, is characterized by a larger so2 adsorption. this indicates that there is an interaction between the so2 and the acidic oxygenated surface groups produced during oxidation and the presence of acid groups improved the extractability of the acid. such oxygenated structures are also responsible for catalytic activity of carbon in so2 oxidation. fig. 10: ftir spectra of 7ni/ac catalyst in the 600-2200 cm -1 region the chemical state of 7ni/45nac was characterized using x-ray diffraction (xrd, shimadzu company) and the crystalline phases were identified by comparison with reference data, international center for diffraction data, (icdd). the results as shown in figure 14 indicate that nio phase shows major peaks but minor ni, ni(oh)2 and ni2o3 peaks are detected. fig. 11: ftir spectra of 7ni/ac catalyst in the 2400-4000 cm -1 region fig. 12: ftir spectra of 7ni/45nac catalyst in the 600-2200 cm -1 region fig. 13: ftir spectra of 7ni/45nac catalyst in the 2400-4000 cm -1 region removal of so2 over modified activated carbon in fixed bed reactor: i, effect of metal oxide loadings and acid treatment 32 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net fig. 14: xrd patterns of 7ni/45nac this is attributed to that all the catalysts were calcined at 400 o c, and ni is rarely formed at this temperature [15]. the coexistence of ni and nio species on the activated carbon favors the flue gas desulfurization. comparison between the performance of nio and cuo supported ac catalysts the desulfurization performance of cu/ac catalysts is shown in figures 15-18. compared with ac, cu/ac catalysts exhibit better performance. the so2 effluent concentration decreased from 60 ppm to zero ppm and the so2 removal efficiency increased from 97.5% to 100% at time duration of 15 minutes. this may be expected due to modifications of physical and chemical properties of ac. the same behavior was obtained by other investigators [14, 25, 26]. the change in sorption breakthrough and removal efficiency with time for different cuo loadings is shown in figures 15 and 16. the results indicate that the removal efficiency increases as the metal loading increases. this behavior is to be expected due to that low loading offer few active sites of cu and thus show lower activity; higher loading above 7wt% resulted in active sites aggregation and consequent reduction of catalytic activity. similar behavior was also obtained with ni/ac catalysts. the breakthrough time and sorption capacity of cu/ac were higher than those of ni/ac. the breakthrough time (τ0.05) for 7cu/ac compared to 7ni/ac increased from 3h to 4h and the sorption capacity increased from 191 mg/g to 200 mg/g as shown in figures 17 and 18. this may be attributed to that cu and its derivatives favoring more transformation of the adsorbed so2 and oxidizing so2 into other more stable so3 and h2so4. the present findings are in agreement with the results obtained by tseng et al. [25] and lόpez et al. [18] but differ from ma et al. [17] who showed that metals play little role in so2 adsorption but a main role in oxidation of so2. fig. 15: effect of cuo loadings on so2 sorption breakthrough neran k. ibraheem, shahrazad r. raouf and zainab a. naser -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 33 fig. 16: dynamic change in so2 removal efficiency for different copper oxide loadings fig. 17: breakthrough time of ni/ac and cu/ac catalysts with different metal loadings fig. 18: sorption capacity of ni/ac and cu/ac catalysts with different metal loadings conclusions 1. for both nickel and copper oxides supported ac catalysts, 7wt% metal loading gave the optimum desulfurization efficiency, sorption capacity and breakthrough time. 2. the chemical state of the 7ni/45nac catalyst as characterized using xrd, shows major peaks for nio phase but minor ni, ni(oh)2 and ni2o3 peaks were detected. 3. fourier transform infra-red (ftir) and surface area tests showed that the oxygen containing functional groups and the surface area of ac increase with increasing the concentration of nitric acid. 4. compared with nickel supported ac catalysts, the copper supported ac catalysts showed similar behavior in so2 removal. however the breakthrough time and sorption capacity of cu/ac catalysts were higher than those for ni/ac. the breakthrough time and sorption capacity for 7cu/ac were 4hours and 200mg/g as compared to 3hours and 191mg/g for ni/ac respectively. notation symbol description unit c exit so2 concentration ppm co initial so2 concentration ppm wf mass of fresh catalyst g ws mass of spent catalyst g τ0.05 breakthrough time min ac activated carbon - mac modified activated carbon - references 1lee, k., t., christopher, k., c., fernando, w., j., bhatia, s., and mahamed, a., "modeling and simulation of flue gas desulfurization using cao/coal fly ash sorbent", j. of chem. eng. of japan, vol. (38), no.(6), pp. (391-396), (2005). 2davis, m., l., and cornwell, d., a., "introduction to environmental engineering", 4 th ed., mcgrawhill, usa, (2008). 3sander, v., h., fisher, h., rothe, u., and kola, r., "sulphur, sulphur dioxide and sulphuric acid", 4 th ed., the british sulphur coporation ltd, london, (1984). removal of so2 over modified activated carbon in fixed bed reactor: i, effect of metal oxide loadings and acid treatment 34 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net 4irvan, "removal of so2 and no from simulated flue gas using rice husk ash/cao/ceo2 sorbent", phd thesis, university sains, malaysia, (2009). 5hanski, t., "feasibility of dry scrubbers for ships and stationary diesel power plants", m.sc. thesis, university of oulu, finland, (2011). 6kohl, a., l., and riesenfeld, f., c., "gas purification", 3 rd ed., houston, texas, (1979). 7lua, a., c., and gou, j., "adsorption of sulfur dioxide on oil-palm-shell activated carbon in a packed bed", sustainable energy and environmental technologies, pp. (430-434), (2000). 8de miguel., s., r., heinen, j., c., castro, a., a., and scelza, o., a., "effect of acid treatment on the properties of an activated carbon", react kinet catal lett, vol. (40), no. (2), pp. (331–335), (1989). 9nakamura, t., yamada, m., and yamaguchi, t., "catalytic properties of mo(co)6 supported on activated carbon for ethene homologation". appl catal, vol. (87), no. (1), pp. (69–79), (1992). 10wang, s., and lu, g., q., "effects of acidic treatments on the power and surface properties of ni catalyst supported on activated carbon", carbon, vol. 36, no. (3), pp. (283-292), (1998). 11tesng, h., h., and wey, m., y., "effects of acid treatments of activated carbon on its physiochemical structure as a support for copper oxide in deso2 recation catalysts", chemosphere, vol. 62, no. (5), pp. (756-766), (2006). 12wang, s., b., and lu, g., q., "effects of acidic treatments on the pore and surface properties of ni catalyst supported on activated carbon", carbon, vol. (36), no. (3), pp. (283 – 292), (1998). 13klinik, j., and grzybek, t., "the influence of cobalt, nickel, manfanese and vanadium to active carbons on their efficiency in so2 removal from stack gases", fuel, vol. (71), no. (1), pp. (1303-1308), (1992). 14martyniuk, h., and więckowska, j., "adsorbents and catalysts from brown coal for flue gas desulfurization", fuel, vol. (74), no. (11), pp.(1716-1718), (1995). 15bekyarova, e., and mehandjiev, d., "studies of ni-impregnated active carbon", j. of colloid and interface science, vol. (179), no. (0243), pp.(509-516), (1996). 16jiaxiu, g., juan, l., yinghao, c., huaqiang, y., and yaoqiang, c., "influence of ni species of ni/ac catalyst on its desulfurization performance at low temperature", chin. j. catal., vol. 31, no. (3), pp. (278-282), (2010). 17ma, j., liu, z., liu, q., guo, s., huang, z., and xiao,y., "so2 and no removal from flue gas over v2o5/ac at lower temperaturesrole of v2o5 on so2 removal", fuel processing technology, vol. (89), no. (3), pp.(242-248), (2008). 18lόpez, d., buitrago, r., escribano, a., reinoso, f., and mondragon, f.," low temperature catalytic adsorption of so2 on activated carbon", j. phys. chem. c, vol. (112), no. (39), pp. (15335-15340), (2008). 19nasir, z., a., "the removal of so2 over modified activated carbon catalyst in fixed bed reactor", m.sc. thesis, university of technology, chemical engineering, iraq, (2012). neran k. ibraheem, shahrazad r. raouf and zainab a. naser -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 35 20richardson, j., t., "principle of catalyst development", plenum press new york, pp. (288), (1989). 21wang, s., and lu, g., q., "effects of acidic treatments on the power and surface properties of ni catalyst supported on activated carbon", carbon, vol. (36), no. (3), pp. (283-292), (1998). 22leon y., leon, c.a. and radovic, l.r., "interfacial chemistry and electrochemistry of carbon surfaces", chemistry and physics of carbon, vol. (24), no. (2), pp. (213-310), (1994). 23tesng, h., h., and wey, m., y., "effects of acid treatments of activated carbon on its physiochemical structure as a support for copper oxide in deso2 recation catalysts", chemosphere, vol. (62), no. (5), pp. (756-766), (2006). 24lisovskii, a., semiat, r., and aharoni, c., "adsorption of sulfur dioxide by active carbon treated by nitric acid: i. effect of the treatment on adsorption of so2 and extractability of the acid formed", carbon, vol. (35), no.(10-11), pp. (1639-1643), (1997). 25tesng, h., h., wey, m., y., and fu, c., h., "carbon materials as catalyst supports for so2 oxidation: catalytic activity of cuo-ac", carbon, vol. (41), no. (1), pp. (139-149), (2003). 26sumathi, s., bhatia, s., lee, k., t., and mohamed, a., r., "cerium impregnated palm shell activated carbon (ce/psac) sorbent for simultaneous removal of so2 and no-process study", j. of chemical engineering, vol. (162), no. (5), pp. (51-57), (2010). iraqi journal of chemical and petroleum engineering vol.14 no.1 (march 2013) 4753 issn: 1997-4884 theoretical study on heat transfer in the presence of fouling waqar abdulwahid abdulnabi al-hallaf chemical engineering department, nahrain university, baghdad, iraq abstract the fouling depositions of crude oil stream were studied theoretically in a shell and tube heat exchanger to investigate the effect of depositions on the heat transfer process. the employed heat exchanger was with steam flowing in the inner tubes and crude oil in the shell at different velocities and bulk temperatures. it is assumed that fouling occurs only on the heated stream side (crude oil). the analysis was carried out for turbulent flow heat transfer conditions with wide range of reynolds number, bulk temperature and time. many previously proposed models for fouling resistance were employed to estimate a new model for fouling rate. it is found that the fouling rate and consequently the heat transfer coefficient were affected by reynolds number, prandtls number, film temperature, activation energy, and time. the results obtained showed that fouling resistance decreased with the increasing of reynolds number and prandtls number, and increased with the increasing of film temperature and time. the analyses of results were compared with some experimental work and a reasonable agreement is attained. keywords heat exchanger, shell and tube, fouling rate, crude oil introduction the term fouling is defined as the deposition of unwanted material on heat transfer equipment, which results in an increase in thermal resistance to heat transfer and subsequent loss of equipment thermal efficiency [1]. fouling leads to reduce heat transfer, increase pressure drop, block process pipes, and these effects are costly. the cost factors include higher heat exchanger requirements, increase fuel consumption, reduce throughput and increase maintenance. in addition to the operation losses, fouling forces significant capital expenditure, these fouling factors are taken into consideration. reported causes of fouling from crude oils include [2]: i) impurities such as water, rust and other particulates. ii) gum or polymeric species formed through oxidation of reactive species in the oils. iii) insoluble asphaltenes from selfincompatible oils or from blending. iv) iron sulphide formation. v) coke formation due to reactions of polar fractions. these factors (i) to (v) become progressively more important as the oil temperature is raised, i.e., factor (i) can predominate at lower temperatures in the preheat train, whereas factors (iv) iraqi journal of chemical and petroleum engineering university of baghdad college of engineering theoretical study on heat transfer in the presence of fouling 48 ijcpe vol.14 no.1 (march 2013) -available online at: www.iasj.net and (v) become more important near the furnace inlet temperature. scaling of the heat exchanger surfaces has been of most concern because of the breakage of the fragile impregnated graphite tubes. figure 1 shows a fouled heat exchanger. fig.1, graphite shell and tube heat exchange. as scaling becomes more serious, maintenance costs and downtime increase, while the production rate decreases. after some time of operation, the internal surfaces of equipment in contact with crude oil are covered with scale, which is removed by washing at high velocity. this descaling action is partly by dissolution and partly by abrasion. the main equipments which require regular washing are: flash chamber, heat exchangers, and acid pipework [3]. parameters affecting the fouling the fouling characteristic of a fluid in contact with a heat transfer surface depends on the following main parameters [4]: 1. flow velocity of the fluid. 2. surface temperature. 3. fluid bulk temperature. 4. material and geometry of the heat transfer surface. 5. characteristics of the fouling fluid. fouling characteristics many types of fouling can occur on the heat transfer surfaces. based on the different physical and chemical processes involved, it is convenient to classify the fouling main types as [4, 5]: precipitation fouling: crystallization of dissolved salts due to solubility changes with temperature, and subsequent precipitation onto the heat transfer surface. particulate fouling: deposition of suspended particles in the process stream onto the heat transfer surfaces. biological fouling "bio-fouling": this type occurs in raw water due to the attachment and growth of macro organisms on the heat transfer surfaces. chemical reaction fouling: is a result of chemical reactions between reactants in the flowing fluid in which the surface material itself is not a reactant. corrosion fouling: due to chemical or electrochemical reaction between the heat transfer surface itself and the fluid stream to produce corrosion products. solidification fouling: due to freezing of a pure liquid or a higher melting point components of a multicomponent solution onto a cooler surface. this paper covers the impact of shell side fouling on the thermal performance and economics of shell and tube heat exchangers employed in the refinery and petrochemical plant processes. fouling curves the fouling process is indicated by the fouling resistance, rf which is measured either by a test section or from the decreased capacity of an operating heat exchanger [4]. the results are presented by rf versus time curve. the delay time, td indicates waqar abdulwahid abdulnabi al-hallaf -available online at: www.iasj.net ijcpe vol.14 no.1 (march 2013) 49 an initial period of time that can elapse where no fouling occurs. the most important fouling curves (fig. 2) are: i) the linear fouling curve: in this mode, the mass of deposition rate, md increases linearly with time and there is no deposition removal, mr, or md mr = constant. the fouling curve in this case takes the form of: rf= a (t-td) … (1) where "a" is the slope of the line as shown in fig. 2 fig.2, fouling curves [4] ii) the asymptotic fouling curve: in this mode, the rate of fouling gradually increases against time, until a steady state is reached when there is an asymptotic fouling resistance, r * f is obtained. in practical industrial situations, the asymptote may be reached in a matter of hours, weeks or months depending on the operation conditions. the general equation describing this behavior takes the form r * f = (1-e β t ) … (2) this mode is the most widely existed in the industrial applications iii) the falling rate fouling curve: in this mode, the mass of deposit increases with time nonlinearly and without reaching a steady state of asymptotic value, i.e., md mr= f (t) and takes the form rf = f (t) … (3) crude oil fouling models a large number of models for crude oil fouling have been presented. ebert and panchal (1995) have presented a fouling model that is expressed as the average (linear) fouling rate under given conditions as a result of two competing terms, namely, a deposition term and a removal term [5, 6, 7, 8, 9]. fouling rate = (deposition term) (removal term) w f f tr e dt dr              expre …(4) where α, β, γ and e are constants to be determined from experimental data. and w  is the tube wall shear stress and can be given by. …(5) the friction factor can be calculated from the blasius equation [9]: 25.0 re0791.0  f … (6) the relationship in eq. (4) points to the possibility of identifying combinations of temperature and velocity below which the fouling rates will be negligible. ebert and panchal present this as the “threshold condition”. this model suggests that the heat exchanger geometry which affects the surface and film temperatures, velocities and shear stresses can be effectively applied to maintain the conditions below the “threshold conditions” in a given heat exchanger. theoretical study on heat transfer in the presence of fouling 50 ijcpe vol.14 no.1 (march 2013) -available online at: www.iasj.net ebert and panchal model assumes all the chemical reactions to be included by the arrhenius term in eq. (4). in addition, it ignores the effects of crude oil thermal conductivity and specific heat and only considers the impacts of crude oil density and viscosity as presented by reynolds number. to modify this correlation, prandtl number was also incorporated into the model by polley etal. (2002) as shown by eq. (7). 8.033.0 reexpprre              w f tr e dt dr … (7) the model differs primarily in the use of wall temperature, tw, in the deposition term and reynolds number rather than wall shear stress in the removal term. saleh et al. (2003) proposed a model that can only be able to predict fouling without considering the effect of fluid velocity on the removal term as follows:           f f tr e up dt dr exp   … (8) the latest threshold fouling model (eq. (9)) has been developed by nasr and givi (2006) which, is independent of prandtl number. …(9) nasr has estimated the constant parameters of eq. (9) using the experimental data, measured by saleh et al. it should be mentioned that to extend the model for the other type of crude oil the constant values have to be recalculated correspondingly. the proposed model to propose a new model the experimental results reported by polley, nasr, and ebert were used. the new model can be expressed by the following equation:           f f tr e dt dr expprre   … (10) film temperature can be obtained by the following equation: wbf ttt  68.032.0 … (11) the activation energy was obtained by drawing ln(drf/dt) versus 1/tf. the following constants were used in the proposed model: α =36.71 (m2 k/ kw hr) β = -0.085 γ = -1.14 e = 22.618 (kj/ mol) the correlation coefficient was 0.943. results and discussion the study was carried out to examine the effect of operating conditions on fouling of crude oil. the following ranges of conditions were covered: velocity of 0.25 to 0.4 m/s, surface temperature of 177 to 245 o c, bulk temperature of 79 to 120 o c. effect of reynolds number velocity effects provide a key to understanding the fouling mechanism. if fouling rates increased with velocity, transport of fouling species is likely important. if fouling rate decreases with increasing velocity the dominant step is likely to be adhesion of foulants at the surface or chemical reaction. as reynolds number was raised from 4051 to 6233, the fouling rate waqar abdulwahid abdulnabi al-hallaf -available online at: www.iasj.net ijcpe vol.14 no.1 (march 2013) 51 decreased from 0.002543m 2 .k/kw. hr to 0.002443 m 2 .k/kw. hr for bulk temperature of 79°c and surface temperature of 245°c. figure 3 shows the relationship between fouling rate and time at different values of reynolds number. fig.3, effect of reynolds number on fouling resistance at tb= 79°c, tw = 245 o c effect of film temperature i) effect of wall temperature as shown in figure 4 fouling rates were most intensive at highest wall temperature. fouling rates ranged from 0.005435 m 2 k/kw. hr at wall temperature of 177 o c to 0.01037 m 2 k/kw. hr at wall temperature of 245 o c for bulk temperature of 79 o c and reynolds number of 3895. fig.4, effect of wall temperature on fouling resistance at tb= 79°c, re = 3895 ii) effect of bulk temperature figure 5 shows fouling resistance versus time for three bulk temperatures of 77, 79 and 120 o c, with fixed wall temperature of 177 o c and reynolds number of 5924. by increasing the bulk temperature from 77 to 120 o c, and hence the film temperature from 145 to 158.8 o c, the fouling rate was increased from 0.001204 to 0.00222 m 2 k/kw. hr. fig.5, effect of bulk temperature on fouling resistance at tw= 177°c, re = 5924 effect of prandtls number figure 6 shows that as prandtls increased from 10.46 to 14.92 the fouling resistance decreased from 0.003449m 2 k/kw. hr to 0.002301 m 2 k/kw. hr for the same values of film temperature and reynolds number. fig.6, effect of prandtls number on fouling resistance at tf= 191.24°c,re = 5924 comparison of the results with proposed models the results of the proposed model were compared with other proposed models carried out at the same conditions for tb= 77°c, tw= 242°c and re= 5924, see fig.7. 0 0.05 0.1 0.15 0.2 0.25 0 20 40 60 80 100 120 time (hr) f o u l i n g r a t e ( m 2 . k / k w ) re=4051 re=5454 re=6233 0 0.2 0.4 0.6 0.8 1 1.2 0 20 40 60 80 100 120 time (hr) f o u l i n g r e s i s t a n c e ( m 2 . k / k w ) tw=177ºc tw=220ºc tw=245ºc 0 0.05 0.1 0.15 0.2 0.25 0 20 40 60 80 100 120 time (hr) f o u l i n g r e s i s t a n c e ( m 2 . k / k w ) tb=77ºc tb=79ºc tb=120ºc 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0 20 40 60 80 100 120 time (hr) f o u l in g r e s is ta n c e (m 2 . k / k w ) pr=10.46 pr=14.2 pr=14.92 theoretical study on heat transfer in the presence of fouling 52 ijcpe vol.14 no.1 (march 2013) -available online at: www.iasj.net fig.7, comparison of the fouling resistance versus time for the proposed model with other models at tb= 77°c, tw= 242°c and re = 5924 conclusion a study of fouling at bulk liquid temperatures of 77-120°c, surface temperatures in the range 177-245°c and reynolds number in the range of 3895-6233 has shown that: 1. fouling rates increase strongly with both the surface and the bulk temperature. 2. surface temperature has a major impact on fouling rates. fouling rate is correlated using a modified film temperature, which gives more weight to the surface temperature than to the bulk temperature. 3. fouling rate decreases as reynolds number increases to the power 0.085. 4. there is a linear dependence of the fouling resistance on time. 5. bulk temperature effect can not be separated from the flow effects, since as the bulk temperature increases, the reynolds number goes up slightly at fixed velocity. 6. fouling rate decreases as prandtls number increases to the power 1.14. nomenclature e activation energy, kj/mol f friction factor, dimensionless p pressure, kpa rf fouling resistance, m 2 k/kw re reynolds number, dimensionless t time, h td delay time, h tb bulk temperature, k or °c tf film temperature, k or °c tw wall temperature, k or °c u fluid velocity, m/s greek symbols α constant parameter in eqs. 4, 7, 8, 9 and 10 β constant parameter in eqs. 4, 7, 8, 9 and 10 δ constant parameter in eq. 10 γ constant parameter in eqs. 4, 7, 8 and 9 ρ density, kg/m 3 τw wall shear stress, n/m 2 acknowledgment the authors are thankful for the comments and advice given by dr. qasim j. m. slaiman and dr. basim o. hasan. they have substantially improved the content of this work and pointed out some research directions of particular interest. references 1. a. s. kovo, (2006), “mathematical modelling and simulation of fouling of nigerian crude oil equipment installations”, leonardo journal of sciences, 9 ,111-124. 2. m.srinivasan and a.p.watkinson, “fouling of some canadian crude oils”, in “heat exchanger fouling and cleaning: fundamentals and applications”, eci conference, santa fe, 2003. 3. r. m. behbahani, h. müllersteinhagen, m. jamialahmadi, “heat exchanger fouling in phosphoric acid evaporators evaluation of data”., conference proceedings eci on heat exchanger fouling, santa fe, 2003. 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0 20 40 60 80 100 120 time (hour) f o u li n g r e s is t a n c e ( m 2 .k /k w ) polley model nasr model ebert model proposed model waqar abdulwahid abdulnabi al-hallaf -available online at: www.iasj.net ijcpe vol.14 no.1 (march 2013) 53 4. m. m. awad, i. f. abd el-wahab and h. e. gad, “effect of surface temperature on the fouling of heat transfer surfaces”, in: eleventh international water technology conference, sharm el-sheikh, egypt, 2007. 5. b. i. master, k. s. chunangad and v. pushpanathan, “fouling mitigation using helixchanger heat exchangers”. in “heat exchanger fouling and cleaning: fundamentals and applications”, eci conference, santa fe, 2003. 6. m.r. jafari nasr, m. majidi, (2006), “modeling of crude oil fouling in preheat exchangers of refinery distillation units”, applied thermal engineering, 26, 1572–1577. 7. j. aminian, s. shahhosseini, (2008), “evaluation of ann modelling for prediction of crude oil behaviour”, applied thermal engineering, 28, 668–674. 8. z. saleh, r. sheikholeslami, a.p. watkinson, (2003), “fouling characteristics of a light australian crude oil”, in: “heat exchanger fouling and cleaning fundamentals and applications”, eci conference, santa fe 2003. 9. d. butterworth, (2002), “design of shell-and-tube heat exchangers when the fouling depends on local temperature and velocity”, applied thermal engineering, 22, 789–801. 10. w. l. nelson, (1959) “petroleum refinery engineering”, mcgrawhill book company, united states of america. 11. d. q. kern, (1950), “process heat transfer”, mcgraw-hill book company, united states of america. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol. 24 no.1 (march 2023) 5 – 11 eissn: 2618-0707, pissn: 1997-4884 *corresponding author: name: kasi njeudjang, email: kasinj2006@yahoo.fr ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. multi-stage hydraulic fracturing completion design based on ball-and-sleeve method kasi njeudjang a, *, alain amougou zanga b, nasr saeed c, théophile ndougsa-mbarga d, and philippe njandjock nouck e a department of quality industrial safety and environment. national advanced school of mines and petroleum industries. university of maroua. po. box: 46, maroua, cameroon b fundamental physics laboratory, department of physics, faculty of science, university of douala, p.o. box 24 157 douala, cameroon c department of physics, college of education, nyala university, p.o. box: 155, nyala, sudan d department of physics, advanced teacher’s training college, university of yaoundé i, po. box 47, yaoundé, cameroon e department of physics, faculty of science, university of yaoundé i, po. box 47, yaoundé, cameroon abstract this paper proposes a completion that can allow fracturing four zones in a single trip in the well called “y” (for confidential reasons) of the field named “x” (for confidential reasons). the steps to design a well completion for multiple fracturing are first to select the best completion method then the required equipment and the materials that it is made of. after that, the completion schematic must be drawn by using power draw in this case, and the summary installation procedures explained. the data used to design the completion are the well trajectory, the reservoir data (including temperature, pressure and fluid properties), the production and injection strategy. the results suggest that multi-stage hydraulic fracturing can be done in a single trip by using the ball-andsleeve method. metallurgy and hydrogenated nitrile are sealing elementary constituent of chromium which are essential materials found in alloy with 13% of chromium. keywords: hydraulic fracturing, well completion, multi-stage fracturing, ball-and-sleeve, power draw. received on 29/12/2022, received in revised form on 11/03/2023, accepted on 12/03/2023, published on 30/03/2023 https://doi.org/10.31699/ijcpe.2023.1.2 1introduction in the beginning, one of the most important motivations in drilling a well is to affirm the presence of hydrocarbons as highlighted in reference [1-4]. in the field x, 7 wells were dried out of 10 and so spending money on them is not required. investigations on the practical petroleum geochemistry for exploration and production as well as the future of oil supply have been carried out to in [5, 6]. the authors of [7, 8] verified if the presence of hydrocarbons were commercially feasible, then production begin after careful installation of some special equipment in the well and this is known as well completion. the articulation between the surface facilities and the reservoir can equally be referred to as completion as stated in [9-11]. and this has made it possible to produce a more safely and efficiently well. to attain the production objectives, the completion string must be properly designed. in some cases, permeability is low, leading to low production rates. this requires hydraulic fracturing to create a conductive path for the fluid from the reservoir to the well [12-14]. this process can significantly increase well productivity and oil and gas reserves. this topic is well addressed in the literature [1518]. however, it deals with only one reservoir. sometimes several reservoir zones are to be produced with a single well as it is more economical. fracturing multiple zones is challenging because one zone has to be isolated while treating another zone [19]. the multistage hydraulic fractured technique has been proven to be a key technique to attain economic production from several kinds of reservoirs [20-23]. hydraulic fracturing is a technology used since 1950 to improve oil production from tight reservoir [24, 25]. it consists of pumping a special fluid at a pressure high enough to initiate cracks in the rock. this process can significantly improve well productivity in low permeability reservoirs. a single well can be frequently produced from many zones due to economic considerations which makes it difficult to fracture them all at once since one zone must be separated while the other is being treated [26, 27]. these costs comprises of completion costs, fluid and proppants costs, and pumping charges [28]. when the operating time of the multi-stage hydraulic fracturing (mshf) is longer, the costs equally increased [29]. recently, several investigations have been carried out to know the most economical method of completion [30]. following the investigation in [30], there’s no existing method of completion that’s the best, but it rather depends on the applications. the total cost of mshf can be reduced by carrying out a single trip operation. to design a completion that can perform http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:kasinj2006@yahoo.fr http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2023.1.2 k. njeudjang et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 5 11 6 hydraulic fracturing of multiple zones in a single trip in the well y of the field x, the aim of this paper is to evaluate the feasibility of this design and to improve the conductivity near the horizontal section of selected well (horizontal well). the mshf operation can be made successful, by constructing a perfect planned ahead. this can be done by choosing the most suitable materials, completion techniques and equipment. for a completion map to be successful, we are require to accomplish the following tasks: (i) select the most appropriate completion techniques and corresponding equipment; (ii) choose a suitable materials so that the equipment can be used during the entire life of the well and (iii) draw the completion schematic and write installation procedures. 2data, methods and results the data used to design the completion is presented in table 1. table 1. completion data representation for well y reservoir data temperature=115°c pressure = 4200 psi fluid api gravity =32 fluid type = naphthenic h2s content= 5ppm; co2 content=2.5mole% well data md at toe =3500 ft inclination= 90° at 2600 mmd productions objectives production strategy= 4 zones commingled zone 4: top=3200 mmd; bottom= 3240 mmd zone 3: top=3300 mmd; bottom= 3315 mmd zone 2: top=3420 mmd; bottom= 3450 mmd zone 1: top=3420 mmd; bottom= 3450 mmd injections objectives operation constraints=fracture in single trip injection prsessure=high (above reservoir break down pressure) based on the data of table 1, the aim of this paper is attain by applying the appropriate economic evaluation and by using the powerdraw software. the powerdraw software is the well and completion schematics drawing program for the oil and gas industry which is a plug-in for microsoft visio. there are shapes for well and completions in powerdraw software. by using the reservoir and well data as the input data of powerdraw software, we can drag and drop the shapes of well and completions found in powerdraw software to build the well and completion schematics, customize them, assemble them, calculate their depths, and write their descriptions in a table. fig. 1, depicts the primary well schematic. in fig. 1, the casing design for well y is consisted of 2 casings (13-3/8” surface casing at 750mmd, 9-5/8” intermediate casing at 1900mmd, both grades are l80) and 2 liners (7” liner at 2600mmd and 4-1/2” liner at 3500mmd, both grades are l80). when the well is at 100 mmd, it is being control by the tubing retrievable security valve (trsv) which constitute 4-1/2’’ of the upper completion, a chemical injection mandrel to allow chemical injection at 1600 mmd, temperature and pressure at 2350 mmd are measure using a gauge mandrel, a landing bust beyond the production crowd and a landing bust beneath the production crowd to set plugs. the nominal weight of tubing with a magnitude of 4-1/2” is 12 pounds per feet, with a division of l80. the tubing string ends with a polished bore receptacle (pbr) and a seal assembly to seal in it. the pbr is used as a tieback for the 4-1/2” liner so that the production string has a consistent diameter of 4-1/2”. fig. 1. schematic of primary well 2.1. metallurgy selection, seal selection and completion method selection the results obtained in this subsection are based on the first-pass selection graph, the corrosion rates as a function of chromium content (sumitomo metals industries, 2008) and the completion data of well y. the qualified pressure of co2 and h2s is 105 psi and 0.021 psi respectively. in assent, one of the most important metallurgy is alloy which constitutes 13% of chromium (13cr). in addition, the temperature of the reservoir is 115°c, which is 239°f. at this temperature, 13cr has a lower corrosion rate than 9cr. fluids with h2s content of 5 ppm, which is less than 10 ppm are kwon as non-aromatic fluids. furthermore, acid stimulation is not needed here, so there will be no presence of hcl. in addition, since there will be no injection of methanol (it is injected when there are hydrates in the well and hydrates form only in low temperatures, which is not the case here), nitrile should be the most appropriate elastomer for the sealing elements. here, the temperature of operation is so close to the overlying maximum of nitrile temperatures. the best solution in this demonstration is done by using hydrogenated nitrile since hcl acid is not present. it has good physical properties and can resist higher temperatures. it is well known that the two most commonly used techniques for a multi-stage hydraulic fracturing are the plug-and-perf technique and the ball-and-sleeve technique [31, 32]. in this case, the most appropriate method is balland-sleeve. the plug-and-perf method requires multiples wireline and coiled tubing runs to place the fracturing fluid. this improved the time and costs to carry out the fracture treatment. moreover, the performance constraint of the fracture treatment in a single trip is clearly executed so that less rig time is required and high costs are saved. the cost of the apparatus to the rig cost is added to guess k. njeudjang et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 5 11 7 the cost of each technique. the pumping charges, fluid and proppants costs are the same for both plug-and-perf and ball-and-sleeve whereas the apparatus and equipment cost are different as shown in table 2 and table 3. table 2. apparatus cost for the “ball-and-sleeve” technique item cost/unit ($) unit cost ($) fracking sleeve 9,000 3 27,000 non-prep toe valve 4,000 1 4,000 isolation valve 5,000 1 5,000 isolation packer 3,500 5 17,500 bullnose 1,000 1 1,000 total cost ($) 54,500 table 3. equipment cost for “plug-and-perf” method item cost/unit ($) unit cost ($) bridge plug 8,000 3 24,000 total cost ($) 24,000 the cost of the apparatus needed for plug-and-perf and ball-and-sleeve, can be compared when plug-and-perf completion appears to be more economical. but the plugand-perf techniques need coiled-tubing interference for perforating and setting plug. it was approximated that the time to rig up (ru) and rig down (rd) between stages is 3 hours. it takes 1 hour to pump the treatment for each stage. the rig cost in shallow water offshore is predicted to be 400,000$ per day. so from calculation, the approximate cost for one hour is 16,667$. the costs of operation for both activities are presented table 4 and table 5. table 4. operation cost for “ball-and-sleeve” method operation cost/time($/hr) time (hr) cost ($) stage treatment 16 ,667 4 66,667 total cost ($) 66,667 table 5. operation cost for "plug-and-perf" method operation cost/time ($/hr) time (hr) cost ($) stage treatment 16,667 4 66,667 ru/rd 16,667 12 200,000 total cost ($) 266,667 now for ball-and-sleeve completion, the costs are 54,500$ for equipment and 66,667$ for operation. the total cost is, therefore, 121,167$. for the plug-and-perf completion, the costs are 24,000$ for equipment and 266,667$ for effectiveness. the total expenditure in this demonstration is 290,667$. in this manifestation, balland-sleeve completion is more sparing. this paper discussed the completion design and its technical feasibility. in this demonstration, the reservoir pressure is 4,200 psi. by using a safety factor of 10%, the maximum working pressure is 4,620 psi. therefore, equipment must be rated at 5,000 psi. also, the working pressure of the equipment should be above 125°c. 2.2. well completion design and running procedure the proposed well y completion design is depicted in fig. 2. fig. 2. proposed well y completion design k. njeudjang et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 5 11 8 in the lower completion, a ball and sleeve method is proposed. this consists of 5 isolation packers, 3 ballactivated fracking sleeves, 1 pressure-activated fracking sleeve or non-prep toe valve, 1 isolation valve and a bullnose as shown in fig. 3. the completion running process of the production section is done in ten steps. initially, the well is perforated and filled with killing fluid then lower completion is run in the hole until total depth with a service tool as shown in fig. 4. the next step is to test all pumping lines to make sure they can deliver the required flow rates. then a ball is dropped to land in the ball seat of the isolation valve, and when the pressure reaches the required pressure, the isolation valve closes. now it is time to set the packers by applying perforated well filled with killing fluid internal pressure as shown in fig. 5. these packers will be set at a specified pressure. of course, the uppermost packer is settled first, followed by the lower packers. the next step is to pump the first stage to fracture the first zone. the fracturing fluid is pumped from the surface, then through the lower completion. at this point, all the ball-activated fracking sleeves are closed. the non-prep toe valve will open at the required pressure and allow the fracturing fluid to enter the annulus between the casing and zone 1 as shown in fig. 6. fig. 3. (a) activation process of a ball-activated fracking sleeve, (b) non-prep toe valve, (c) isolation valve and (d) bullnose fig. 4. (a) 4-1/2" liner initially and (b) lower completion run in hole fig. 5. packers are set, and the first stage is ready to be pumped k. njeudjang et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 5 11 9 fig. 6. fluid flow when treating zone 1 the second stage is to treat the zone 2 and isolate zone 1 at the same time. the smallest ball is dropped in the well and guided by the fluid to the lowest ball seat as shown in fig. 7. the ball reaches the first ball seat, and when enough pressure is applied to it, the sleeve shifts and opens the ports as shown in fig. 8. the third stage is pumped from the surface through the lower completion. the ball-activated fracking sleeves in front of zone 3 and zone 4 are still closed. the fluid enters the annular between the casing and zone 2. the ball prevents the fluid from going to zone 1. after treating zone 2, the next size ball is dropped from the surface and reaches the seat of the ball-activated fracking sleeve in front of zone 3. when enough pressure is applied, the ball-activated fracking sleeve is opened and zone 3 is treated as shown in fig. 9. after treating zone 3, the fourth stage is started where the largest ball is dropped from the surface and guided until it reaches the seat of the uppermost ball fracking sleeve. when enough pressure is applied above the ball, the sleeve shifts and the ports are open. zone 4 is treated while the other zones are isolated as shown in fig. 10. now that all the 4 zones are treated, the service tool can be pulled out of the hole. the balls are dissolved after a few hours, and the treated zone can be produced at the same time. fig. 7. first ball is dropped in the well and guided fig. 8. first ball fracking sleeve is opened, and zone 2 is ready for treatment fig. 9. treatment of zone 3 fig. 10. treatment of zone 4 k. njeudjang et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 5 11 10 3conclusion this paper present a completion outline to fracture 4 zones in a solitary trip needed in well y of the field x. we found out that metallurgy and hydrogenated nitrile are sealing elementary constituent of chromium which are essential materials found in alloy with 13% of chromium. in addition, it was found that in a corrosive environment, the resistance of steel at a temperature of 239°f is increase by adding 13% of chromium to produce better results than when 9% chromium is added. in the presence of fluids such as fabricated fluid, completion fluid, and fracturing fluid, both metallurgy and hydrogenated nitrile could be used. but the operating temperature of the borehole was very close to the overlying maximum of nitrile applications, and hydrogenated nitrile was finally justified. the best completion technique, in this case, was the ball and sleeve method because it is the only one that can be performed in a single trip, and it is economical. to fracture the 4 zones in a single trip, 5 isolations packers, 3 ball-activated fracking sleeves, 1 non-prep toe valve, 1 isolation valve and 1 bullnose were needed. the packers isolated the annulus between the completion string and the casing, leaving this annulus as the only way to fracture and produce a target zone. the ball activated fracking sleeves isolated the lower zone while treating the upper zone, and later dissolution of the ball permitted commingled production. the non-prep toe valve has the same role as the fracking sleeve, but it is more economical to use it for the first stage. finally, the isolation valve allowed setting packers. here, the temperature of operation is so close to the overlying maximum of nitrile temperatures. references [1] total, formation of hydrocarbon deposits planet energies, 20, 10-12 (2014). [2] m. economides, petroleum production systems. prentice-hall (1994). [3] m. alain, geology and geodynamics of hydrocarbons, encyclopedia of energy 5, 11-15 (2014). [4] n. arzhang, best method for enhanced oil recovery from saravak reservoir abd analyse sensitive parameters. thesis. iran, 105 (2016). [5] harry, jr., practical petroleum geochemistry for exploration and production, elsevier, usa (2017). [6] r. g. miller and s. r. sorrell, the future of oil supply, phil. trans. r. soc. a 372, 2013017920130205 (2014), https://doi.org/10.1098/rsta.2013.0179. [7] desorcy g. j., estimation methods for proved recoverable reserves of oil and gas. 10th petoleum congress, 58 (1979). [8] w. oswald, k. harper, p. barickman, using growth and decline factors to project voc emissions from oil and gas production, journal of the air & waste management association 65, 64-73 (2015), https://doi.org/10.1080/10962247.2014.960104. [9] r. john and l. richard, introduction to petroleum engineering. wiley, new jersey (2017). [10] a. hernandez, fundamentals of gas lift engineering: well design and troubleshooting. elsevier inc. (2016). [11] b. guo, w. c. lyons and a. ghalambor, petroleum production engineering a computer assisted approch. (e. s. books, éd.) (2007). [12] a. dheyauldeen, et al., effect of well scheduling and pattern on project development management in unconventional tight gas reservoirs, arabian journal of geosciences 15.14, 1-22 (2022), https://doi.org/10.1007/s12517-022-10500-z. [13] q. lei, w. xiong, j. yuan, s. gao & y. s. wu, behavior of flow through low-permeability reservoirs, in europec/eage conference and exhibition. onepetro (2008), https://doi.org/10.2118/113144-ms. [14] a. dheyauldeen et al., performance evaluation of analytical methods in linear flow data for hydraulically-fractured gas wells, journal of petroleum science and engineering 208, 109467 (2022), https://doi.org/10.1016/j.petrol.2021.109467. [15] a. z. abidina, t. puspasari and w. a. nugroho, polymers for enhanced oil recovery technology (vol. 4). bandung: elsevier (2012), https://doi.org/10.1016/j.proche.2012.06.002. [16] j. bellarby, well completion design, first edition, elsevier, amsterdam, nertherlands 304-367 (2009). [17] d. matanovic, m. cikes and b. moslavac, sand control in well construction and operation, springer, environmental science and engineering (2012). [18] b. bailey, m. crabtree, j. tyrie, j. elphick, kuchuk f, c. romano, l. roodhart, water control, oilfield review 12, 30-51 (2000). [19] m. economides & k. nolte, reservoir stimulation. 3rd ed. chichester: john wiley & sons (2000). [20] m. abdul ameer & s. hamed allah, experimental work to study the behavior of proppant inside the hydraulic fractures and the plugging time, iraqi journal of chemical and petroleum engineering, 17, 57–69 (2016). [21] m. m. rahman, m. m. hossain, d. g. crosby, m. k. rahman & s. s. rahman, analytical, numerical and experimental investigations of transverse fracture propagation from horizontal wells, journal of petroleum science and engineering 35, 127–150 (2002), https://doi.org/10.1016/s09204105(02)00236-x. [22] o. al-fatlawi, m. hossain, n. patel & a. kabir, evaluation of the potentials for adapting the multistage hydraulic fracturing technology in tight carbonate reservoir, in spe middle east oil and gas show and conference. onepetro (2019, march), https://doi.org/10.2118/194733-ms. [23] al-sudani, j. a., & husain, k. m. (2017). evaluation of acid and hydraulic fracturing treatment in halfaya oil field-sadi formation. iraqi journal of chemical and petroleum engineering, 18(4), 25–33. https://doi.org/10.1098/rsta.2013.0179 http://pascal-francis.inist.fr/vibad/index.php?action=getrecorddetail&idt=pascal8130342482 http://pascal-francis.inist.fr/vibad/index.php?action=getrecorddetail&idt=pascal8130342482 http://pascal-francis.inist.fr/vibad/index.php?action=getrecorddetail&idt=pascal8130342482 https://doi.org/10.1080/10962247.2014.960104 https://books.google.iq/books?hl=en&lr=&id=dbipdqaaqbaj&oi=fnd&pg=pp13&dq=introduction+to+petroleum+engineering&ots=ahapbksjht&sig=-yaex5vi20zi6eb003qgkcha8ia&redir_esc=y#v=onepage&q=introduction%20to%20petroleum%20engineering&f=false https://books.google.iq/books?hl=en&lr=&id=dbipdqaaqbaj&oi=fnd&pg=pp13&dq=introduction+to+petroleum+engineering&ots=ahapbksjht&sig=-yaex5vi20zi6eb003qgkcha8ia&redir_esc=y#v=onepage&q=introduction%20to%20petroleum%20engineering&f=false https://books.google.iq/books?hl=en&lr=&id=dfircqaaqbaj&oi=fnd&pg=pp1&dq=%5b10%5d%09a.+hernandez,+fundamentals+of+gas+lift+engineering:+well+design+and+troubleshooting.+elsevier+inc.+(2016).&ots=b902yan_kj&sig=evhlzjvyrntxtheobcvw3jegdw8&redir_esc=y#v=onepage&q=%5b10%5d%09a.%20hernandez%2c%20fundamentals%20of%20gas%20lift%20engineering%3a%20well%20design%20and%20troubleshooting.%20elsevier%20inc.%20(2016).&f=false https://books.google.iq/books?hl=en&lr=&id=dfircqaaqbaj&oi=fnd&pg=pp1&dq=%5b10%5d%09a.+hernandez,+fundamentals+of+gas+lift+engineering:+well+design+and+troubleshooting.+elsevier+inc.+(2016).&ots=b902yan_kj&sig=evhlzjvyrntxtheobcvw3jegdw8&redir_esc=y#v=onepage&q=%5b10%5d%09a.%20hernandez%2c%20fundamentals%20of%20gas%20lift%20engineering%3a%20well%20design%20and%20troubleshooting.%20elsevier%20inc.%20(2016).&f=false https://books.google.iq/books?hl=en&lr=&id=dfircqaaqbaj&oi=fnd&pg=pp1&dq=%5b10%5d%09a.+hernandez,+fundamentals+of+gas+lift+engineering:+well+design+and+troubleshooting.+elsevier+inc.+(2016).&ots=b902yan_kj&sig=evhlzjvyrntxtheobcvw3jegdw8&redir_esc=y#v=onepage&q=%5b10%5d%09a.%20hernandez%2c%20fundamentals%20of%20gas%20lift%20engineering%3a%20well%20design%20and%20troubleshooting.%20elsevier%20inc.%20(2016).&f=false https://books.google.iq/books?hl=en&lr=&id=lkn-ovihxduc&oi=fnd&pg=pp1&dq=petroleum+production+engineering+a+computer+assisted+approch&ots=44zzp7rz3a&sig=9wtaduzfxwi8fqejpxgpdvcejm0&redir_esc=y#v=onepage&q=petroleum%20production%20engineering%20a%20computer%20assisted%20approch&f=false https://books.google.iq/books?hl=en&lr=&id=lkn-ovihxduc&oi=fnd&pg=pp1&dq=petroleum+production+engineering+a+computer+assisted+approch&ots=44zzp7rz3a&sig=9wtaduzfxwi8fqejpxgpdvcejm0&redir_esc=y#v=onepage&q=petroleum%20production%20engineering%20a%20computer%20assisted%20approch&f=false https://books.google.iq/books?hl=en&lr=&id=lkn-ovihxduc&oi=fnd&pg=pp1&dq=petroleum+production+engineering+a+computer+assisted+approch&ots=44zzp7rz3a&sig=9wtaduzfxwi8fqejpxgpdvcejm0&redir_esc=y#v=onepage&q=petroleum%20production%20engineering%20a%20computer%20assisted%20approch&f=false https://doi.org/10.2118/113144-ms https://doi.org/10.1016/j.petrol.2021.109467 https://doi.org/10.1016/j.proche.2012.06.002 https://books.google.iq/books?hl=en&lr=&id=splyvzvygjoc&oi=fnd&pg=pp1&dq=well+completion+design&ots=jxw5-zhlki&sig=r5pyfnt-ybj-5yyphz_mub0ajfu&redir_esc=y#v=onepage&q=well%20completion%20design&f=false https://books.google.iq/books?hl=en&lr=&id=splyvzvygjoc&oi=fnd&pg=pp1&dq=well+completion+design&ots=jxw5-zhlki&sig=r5pyfnt-ybj-5yyphz_mub0ajfu&redir_esc=y#v=onepage&q=well%20completion%20design&f=false https://books.google.iq/books?hl=en&lr=&id=oojd8vlzxnmc&oi=fnd&pg=pr5&dq=%5b17%5d%09d.+matanovic,+m.+cikes+and+b.+moslavac,+sand+control+in+well+construction+and+operation,+springer,+environmental+science+and+engineering+(2012).&ots=sazvmorjxc&sig=ieyeuut0trz8e8eawjawigrr2qu&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=oojd8vlzxnmc&oi=fnd&pg=pr5&dq=%5b17%5d%09d.+matanovic,+m.+cikes+and+b.+moslavac,+sand+control+in+well+construction+and+operation,+springer,+environmental+science+and+engineering+(2012).&ots=sazvmorjxc&sig=ieyeuut0trz8e8eawjawigrr2qu&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=oojd8vlzxnmc&oi=fnd&pg=pr5&dq=%5b17%5d%09d.+matanovic,+m.+cikes+and+b.+moslavac,+sand+control+in+well+construction+and+operation,+springer,+environmental+science+and+engineering+(2012).&ots=sazvmorjxc&sig=ieyeuut0trz8e8eawjawigrr2qu&redir_esc=y#v=onepage&q&f=false yrfjfypyjskfhdpx3dxqd6strhtlheoceudvcq0t43xv6ooozteiyewztvek9s5sserjl8s4apsq4yxnvc0axbxqv1pmtfdrqjxymbsusow0yo32p6fw26fcfti5kwrxcwcfmddtmehyvzvl7jnsfrxrau1jxbqp6wodua__ yrfjfypyjskfhdpx3dxqd6strhtlheoceudvcq0t43xv6ooozteiyewztvek9s5sserjl8s4apsq4yxnvc0axbxqv1pmtfdrqjxymbsusow0yo32p6fw26fcfti5kwrxcwcfmddtmehyvzvl7jnsfrxrau1jxbqp6wodua__ yrfjfypyjskfhdpx3dxqd6strhtlheoceudvcq0t43xv6ooozteiyewztvek9s5sserjl8s4apsq4yxnvc0axbxqv1pmtfdrqjxymbsusow0yo32p6fw26fcfti5kwrxcwcfmddtmehyvzvl7jnsfrxrau1jxbqp6wodua__ file:///c:/users/mekat/downloads/reservoirstimulation3thedition.pdf file:///c:/users/mekat/downloads/reservoirstimulation3thedition.pdf https://www.iasj.net/iasj/download/d6653a36f629d34d https://www.iasj.net/iasj/download/d6653a36f629d34d https://www.iasj.net/iasj/download/d6653a36f629d34d https://www.iasj.net/iasj/download/d6653a36f629d34d https://www.iasj.net/iasj/download/d6653a36f629d34d https://doi.org/10.1016/s0920-4105(02)00236-x https://doi.org/10.1016/s0920-4105(02)00236-x https://doi.org/10.1016/s0920-4105(02)00236-x https://doi.org/10.2118/194733-ms https://www.iasj.net/iasj/download/949cfcc394be7e41 https://www.iasj.net/iasj/download/949cfcc394be7e41 https://www.iasj.net/iasj/download/949cfcc394be7e41 https://www.iasj.net/iasj/download/949cfcc394be7e41 k. njeudjang et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 5 11 11 [24] f. aminzadeh, hydraulic fracturing and well stimulation. 1st ed. hoboken: jon wiley & sons (2009). [25] j. speight, handbook of hydraulic fracturing. hoboken: jon wiley & sons (2016). [26] r. kleinberg, s. paltsev, t. boersma & d. hobbs, tight oil market dynamics: benchmarks, breakeven points, and inelasticities. energy economics 70, 7083 (2018), https://doi.org/10.1016/j.eneco.2017.11.018. [27] a. singh, l. soriano & m. lal, comparison of multistage fracture placement methods for economic learning and unconventional completion optimization: a case history. texas, society of petroleum engineers, 20 (2017), https://doi.org/10.2118/184839-ms. [28] h. jabbari & s. benson, hydraulic fracturing design optimization bakken case study. san francisco, american rock mechanics association, pp. 1-6 (2013). [29] o. al-fatlawi, m. hossain, & a. essa, optimization of fracture parameters for hydraulic fractured horizontal well in a heterogeneous tight reservoir: an equivalent homogeneous modelling approach, in spe kuwait oil & gas show and conference, onepetro. (2019), https://doi.org/10.2118/198185-ms. [30] p. mathur & n. kumar, contrast between plug-andperf method and ball and sleeve method for horizontal well stimulation, at spe sub-regional meet held at upes, dehradun (2016). [31] j. h. lee, m. h. lee and g. h. jang, effect of an hourglass-shape tapered sleeve on the performance of the fluid dynamic bearings of a hdd spindle motor, asme 2013 conference on information storage and processing systems (2013), https://doi.org/10.1115/isps2013-2870. [32] e. a. alali, m. a. bataweel, r. ernesto arias urbina and a. bulekbay, critical review of multistage fracturing completions and stimulation methods, abu dhabi international petroleum exhibition & conference, spe-203284-ms (2020), https://doi.org/10.2118/203284-ms. https://books.google.iq/books?hl=en&lr=&id=hrorcgaaqbaj&oi=fnd&pg=pp7&dq=%5b25%5d%09j.+speight,+handbook+of+hydraulic+fracturing.+hoboken:+jon+wiley+%26+sons+(2016).+&ots=op0eu6ox2u&sig=alkapc5qfkvbzit3yral3orktra&redir_esc=y#v=onepage&q=%5b25%5d%09j.%20speight%2c%20handbook%20of%20hydraulic%20fracturing.%20hoboken%3a%20jon%20wiley%20%26%20sons%20(2016).&f=false https://books.google.iq/books?hl=en&lr=&id=hrorcgaaqbaj&oi=fnd&pg=pp7&dq=%5b25%5d%09j.+speight,+handbook+of+hydraulic+fracturing.+hoboken:+jon+wiley+%26+sons+(2016).+&ots=op0eu6ox2u&sig=alkapc5qfkvbzit3yral3orktra&redir_esc=y#v=onepage&q=%5b25%5d%09j.%20speight%2c%20handbook%20of%20hydraulic%20fracturing.%20hoboken%3a%20jon%20wiley%20%26%20sons%20(2016).&f=false https://doi.org/10.1016/j.eneco.2017.11.018 https://doi.org/10.2118/184839-ms https://onepetro.org/armausrms/proceedings-abstract/arma13/all-arma13/120999 https://onepetro.org/armausrms/proceedings-abstract/arma13/all-arma13/120999 https://onepetro.org/armausrms/proceedings-abstract/arma13/all-arma13/120999 https://onepetro.org/armausrms/proceedings-abstract/arma13/all-arma13/120999 https://doi.org/10.2118/198185-ms https://doi.org/10.1115/isps2013-2870 https://doi.org/10.2118/203284-ms iraqi journal of chemical and petroleum engineering vol.15 no.3 (september 2014) 71-76 issn: 1997-4884 new viscosity correlation for different iraqi oil fields rwaida kaiser abdulmajeed petroleum engineering department, college of engineering, university of baghdad abstract viscosity is one of the most important governing parameters of the fluid flow, either in the porous media or in pipelines. so it is important to use an accurate method to calculate the oil viscosity at various operating conditions. in the literature, several empirical correlations have been proposed for predicting crude oil viscosity. however, these correlations are limited to predict the oil viscosity at specified conditions. in the present work, an extensive experimental data of oil viscosities collected from different samples of iraqi oil reservoirs was applied to develop a new correlation to calculate the oil viscosity at various operating conditions either for dead, saturated or under saturated reservoir. validity and accuracy of the new correlation was confirmed by comparing the obtained results of this correlation and other ones, with experimental data for iraqi oil samples. it was observed that the new correlation gave the most accurate agreement with the experimental data. keywords: viscosity, oil, correlation, under saturated oil, dead oil, saturated oil introduction crude oil viscosity is an important physical property that controls and influences the flow of oil through porous media and pipes. also, crude oil viscosity plays a key role in designing any eor process and has influential role in multiphase flow through tubing and piping system [1]. the viscosity, in general, is defined as the internal resistance of the fluid to flow. the oil viscosity is a strong function of the temperature, pressure, oil gravity, gas gravity, and gas solubility. whenever possible, oil viscosity should be determined by laboratory measurements at reservoir temperature and pressure. according to the pressure, the viscosity of crude oil can be classified into three categories:  dead-oil viscosity: the dead-oil viscosity is defined as the viscosity of crude oil at atmospheric pressure (no gas in solution) and system temperature. the knowledge of the dead oil viscosity is one of the most important factors in developing viscosity empirical correlations because the other viscosities are obtained from it. [2]  saturated-oil viscosity: the saturated (bubble-point) oil viscosity is defined as the viscosity of the crude oil at the bubble-point pressure and reservoir temperature.  undersaturated-oil viscosity: the undersaturated oil viscosity is iraqi journal of chemical and petroleum engineering university of baghdad college of engineering new viscosity correlation for different iraqi oil fields 72 ijcpe vol.15 no.3 (september 2014) -available online at: www.iasj.net defined as the viscosity of the crude oil at a pressure above the bubblepoint and reservoir temperature [3]. numerous correlations have been proposed to calculate the oil viscosity. hence, seven well known correlations were used to predict viscosity of undersaturated oil; these correlations are beal (1946) [4]; beggs and robinson (1975) [5]; vasquez and beggs (1980) [6]; khan correlation (1987) [7]; labedi (1992) [8]; kartoatmodjo and schmidt (1994) [9] and petrosky and farshad (1995) [10] as shown in table 1 table 1: summary of numerous viscosity correlations correlations beal correlation, [4] ( ) ( ) beggs and robinsons correlation, [5] ( ) where : (– ( ) ) vazquez and beggs, [6] ( ) where: (– ) khan et.al correlation, [7] ( ( )) labedi correlation, [8] [ ] ( ) kartomodjo and schmidt correlation, [9] ( ) ( ) petrosky and farshad correlation, [10] ( ) where: ( ) [ ( )] – [ ( )] these correlations usually vary in complexity and accuracy depending upon the available data on the crude oil which is at under saturated reservoir pressure. since, the objective of this study is to use an accurate correlation to calculate the oil viscosity at various operating conditions. in the literature, several empirical correlations have been proposed for calculating the dead, saturated, and under saturated oil viscosity. the present work the developed correlation is based on (612) field data sets collected from different iraqi fields in khasib, rumaila, and mishrif formations. each data set contains temperature, gas oil ratios, api gravity, saturated pressure. these data were divided into six groups according to formations; a set that consisted of (516) was used to cross-validate the relationship established during the training process and, the second group which consisted of (96) was used to test the correlation to evaluate their accuracy and trend stability. reservoir oil viscosities have been measured at various pressures above and below the bubble point pressure for different temperatures. error analysis two criteria were used to compare the performance and accuracy of this correlation with those of seven correlations. these criteria are: a. the average absolute relative error, rwaida kaiser abdulmajeed -available online at: www.iasj.net ijcpe vol.15 no.3 (september 2014) 73 eq. 1: ∑ [| ( ) ( ) ( ) |] …(1) b. the standard deviation error, eq. 2: √( ∑ [| ( ) ( ) ( ) |] ) …(2) the new correlation the suggested form of the viscosity correlation should first maintain the physics before the trails that could be made to find the best fitness. the formulation should involve all dependable parameters affecting crude oil viscosity to provide the reliability for the proposed correlation. a successful trail was made to collect all trained data which are above, at and below bubble point pressure in one new correlation, considered to be a superior correlation to other available correlations. therefore, the suggested correlation can be applied for pressure values that are above or below bubble point pressure; this characteristic may support the reliability other than available correlations in the literatures that used two different formulas to be applied for pressure values that are larger or less than bubble point pressures. generating the new formula established on the dimensionless fitting between ( ) and( ), it is found that this relation takes excellent fitters and unique for all the collected samples for all fields. however, the relationship was adjusted with reservoir temperature, saturation pressure, api gravity and solution gasoil ratio which control the viscosity calculations. the suggested formula can be written using the following form: ( ) [ ( ) ] …(3) where: ( ) – the applications of present work the predicted viscosity using the presented model given in equation 3 has been compared with the actual field data and other seven well known correlations available to the literature (beal, [4]; beggs and robinson, [5]; vasquez and beggs, [6]; khan correlation, [7]; labedi, [8]; kartoatmodjo and schmidt, [9] and petrosky and farshad, [10]) as shown in figures 1,2,3,4,5,6. fig. 1: results of comparison between new and other correlation with the actual data for ad1-k2 fig. 2: results of comparison between new and other correlation with the actual data for ad2-k2 new viscosity correlation for different iraqi oil fields 74 ijcpe vol.15 no.3 (september 2014) -available online at: www.iasj.net fig. 3: results of comparison between new and other correlation with the actual data for ad3-k2 fig. 4: results of comparison between new and other correlation with the actual data for ad1ru1 fig. 5: results of comparison between new and other correlation with the actual data for ad1ru3 fig. 6: results of comparison between new and other correlation with the actual data for ad1mi4 table 2: the standard deviation error % between the new correlation and the seven correlations for different formations correlation standard deviation error % ad1-k2 ad2k2 ad3-k2 ad1-ru1 ad1-ru3 ad1-mi4 beal, [4] 46.54 46.63 50.22 49.62 49.90 48.08 beggs and robinson, [5] 47.01 47.42 49.74 50.85 50.94 47.26 vasquez and beggs, [6] 47.01 47.42 49.74 50.85 50.94 47.26 khan, [7] 46.94 47.36 49.83 50.95 50.75 47.41 labedi, [8] 46.16 46.66 51.29 49.17 48.19 47.90 kartoatmodjo and schmidt, [9] 46.72 46.66 49.98 49.39 50.02 48.12 petrosky and farshad, [10] 44.75 46.27 50.56 51.04 48.58 47.79 new model 1.59 1.58 0.55 1.60 1.08 1.30 results and discussion the results shown in figures 1,2,3,4,5,6 and the obtained standard deviation percentage error between the new and other correlations for all tested formations could be collected to provide the total standard deviation error as shown in fig. 7; this figure rwaida kaiser abdulmajeed -available online at: www.iasj.net ijcpe vol.15 no.3 (september 2014) 75 shows the given correlation that provides the most accurate results than the other presented correlations. it gives (1.72 %) standard deviation error compared with the other correlations which give at least double standard deviation error that is obtained by the new correlation. while, the new correlation gives also lower average absolute relative error than the other correlations as shown in fig. 8. notice that the present model works for various reservoir conditions. fig. 7: the total standard deviation error % for the new and the other seven correlations for all formations fig. 8: the average absolute relative error % for the new and the other seven correlations for all formations conclusion it could be concluded that the present correlation can be considered an accurate correlation to predict the most accurate viscosity data for various reservoir and fluid properties below and above bubble point pressure, instead of using different formulas. nomenclature aare: average absolute relative error. ad: ahdab field. k: khasib formation. ad1-k2: well ahdab 1 – khasib formation, unit 2. ad2-k2: well ahdab2 – khasib formation, unit2. ad3-k2: well ahdab3 – khasib formation, unit2. ru: rumaila formation. ad1-ru1: well ahdab1 –rumaila formation, unit1. ad1-ru3: well ahdab1 –rumaila formation, unit3. mi: mishrif formation ad1-mi4: well ahdab1 –mishrif formation, unit4. eor: enhance oil recovery. gor: gas-oil ratio, scf/stb p: pressure, psi. pb: bubble point pressure, psi. sd: standard deviation. t: temperature, º f. api: oil api gravity μo: oil viscosity, cp. μob: oil viscosity at bubble point pressure, cp. μod: dead oil viscosity, cp. references 1muhammad k. z., mohd. n. d.: “developed correlation to estimate the malaysian crude oil density and viscosity”. sci.int.(lahore),25(2),317318,2013; issn 1013-5316; coden: sinte 8 2kamilu f.o., and ubong w. u.: “predicting the dead oil viscosity of reservoir fluids: a case study of the niger delta” journal of energy new viscosity correlation for different iraqi oil fields 76 ijcpe vol.15 no.3 (september 2014) -available online at: www.iasj.net technologies and policy, issn 2224-3232 (paper) issn 2225-0573 (online) vol.3, no.13, 2013 3ahmed tarek:“reservoir engineering handbook, 2nd edition,” gpc, tx, 2001. 4beal, c., 1946. “viscosity of air, water, natural gas, crude oil and its associated gases at oil field temperature and pressures”. trans. aime 165, 114– 127. 5beggs, h.d., robinson, j.r., 1975. “estimating the viscosity of crude oil systems”. jpt 9, 1140– 1141. 6vazquez, m., beggs, h. d., 1980, correlations for fluid physical property prediction.jpt, 6, pp 968970. 7khan, s. a., et al., “viscosity correlations for saudi arabian crude oils,” spe paper 15720, presented at the fifth spe middle east conference held in manama, bahrain, march 7-10, 1987. 8labedi, r., 1992. “improved correlations for predicting the viscosity of light crudes”. j. pet. sci. engineering. (journal of petroleum science and engineering), 8, 221– 234. 9kartoatmodjo, f., schmidt, z., 1994. “large data bank improves crude physical property correlation”. oil gas j. july 4, 51– 55. 10petrosky, g.e., farshad, f.f., ”viscosity correlations for gulf of mexico crude oils.spe 29468, production operations symposium, oklahoma city, oklahoma,2-4 april, 1995, isbn 978-1-55563448-3. iraqi journal of chemical and petroleum engineering vol.14 no.2 (june 2013) 4955 issn: 1997-4884 reverse osmosis polyamide membrane for the removal of blue and yellow dye from waste water nada mustafa h. al – nakib biochemical engineering department, al-khwarizmi college of engineering _ university of baghdad _ iraq abstract the present work aims to study the removal of dyes from wastewater by reverse osmosis process. two dyes were used direct blue 6, and direct yellow. experiments were performed with feed concentration (75 – 450 ppm), operation temperature (30 – 50 o c) and time (0.2 – 2.0 hr). the membrane used is thin film composite membrane (tfc). it was found that modal permeate concentration decreases with increasing feed concentration and time operating, while permeate concentration increases with increasing feed temperature. also it was found that product rate increase with increasing temperature, but it decrease with increasing feed concentration and time. the concentration of reject solution showed an increase with increasing feed concentration of dyes and feed temperature, while decreases with increasing time operating of reverse osmosis unit. the maximum rejection for direct blue 6 and direct yellow are 98.89% and 98.30% respectively. the maximum recovery percentage for direct blue 6 and direct yellow are 17.84% and 18.20% respectively. the maximum concentration factor of direct blue 6 is 1.227 and for direct yellow is 1.272. keywords: reverse osmosis, dyes (direct blue 6, direct yellow), fouling, membranes introduction large amounts of dyes are used for various industrial applications; especially in the textile industries for dyeing cotton petrinic [1]. the textile industry is characterized by using huge quantity of water. in fact the wastewater from textile dyeing industry is ranked the most polluting among all industrial sectors when considering both volume and composition and is classified is nontoxic although it contains a variable chemical composition of organic compounds such as synthetic dyes, surfactants, emulsifiers, cellulose and derivatives, starch, carbamide, nitrols and other organic substances chokrabarti [2] and manoskovn [3]. dyes are mostly stable in light and heat. also application of technologies which give more stability in the environment against sunlight, bleaches and oxidants, should be considered gholami [4] and bouy [5]. the classic and conventional treatment methods for these types of effluents are based on chemical precipitation, activated sludge, chloriation and adsorption of activated carbon and membrane process allen [6] albanis [7] and mohamed [8]. in the recent years, iraqi journal of chemical and petroleum engineering university of baghdad college of engineering reverse osmosis polyamide membrane for the removal of blue and yellow dye from waste water 50 ijcpe vol.14 no.2 (june 2013) -available online at: www.iasj.net several factors have led to the development of membrane separation technology. membrane process are often chosen in water treatment technology since these applications achieve high removals of constituents such as dissolved solids, organic carbon, inorganic ions. membrane processes such as reverse osmosis (ro), microfiltration (mf), nanofiltration (nf) and ultrafiltration (uf) are used around the world for potable and ultra-pure water production, chemical process separations, as well as desalination of seawater. microfiltration and ultrafiltration used as pretreatment for nanofiltration and reverse osmosis processes. membrane separation processes are also used in food and diary industries, pharmaceutical and cosmetics production, water softening, ultra water production for electronic industries as well as treatment of municipal and industrial wastewater and agricultural drainage water. reverse osmosis desalination has the advantage from the point of view of energy consumption, high product quality and flexible design and installation cheryan [9]. the reverse osmosis membrane separation process called hyperfiltration because it will be noticed that reverse osmosis bears some resemblance to filtration, in that both involve removing a liquid from a mixture by passing it through a device that holds back other substance ulrich [10]. it is a general and widely applicable technique for the separation, concentration or fractionation of substances in fluid solutions. it consists in letting the fluid mixture flow under pressure through an appropriate porous membrane, and with drawing the membrane permeated product generally at atmospheric pressure and surrounding temperature; the product is enriched in one or more constituents of the mixture, leaving a concentrated solution of other constituents on the upstream side of the membrane sourirajan [11]. the choice of membrane material directly influences the separation efficiency. for obtaining a good efficiency, the membrane material must have high affinity for the solvent, and low affinity for the solute. the most common reverse osmosis membrane which attained the stage of economic application in water purification plants are made of cellulose acetate (ca) or polyamide (pa) dan [12]. membrane technology can reduce the volume, recover and recycle valuable component from the waste streams and /or remove recover the thermal energy in hot waste water liv [13] and koyuncu [14]. reverse osmosis performance can be expressed in terms of recovery and rejection: 1recovery factor (y) is defined as the fraction of the feed flow that passes through the membrane *100 …(1) where qp is the permeate volumetric flowrate (m 3 s -1 ) and qf is the fead stream flowrate, hasan [15]. 2rejection percentage (r) defined as the extent to which a solute is rejected by the membrane …(2) where cp is the permeate concentration [kg/m 3 ] and cf is the feed stream concentration [15]. 3concentration factor: the concentration factor (cf) is the ratio of concentration of solute (dissolved species) in the nada mustafa h. al – nakib -available online at: www.iasj.net ijcpe vol.14 no.2 (june 2013) 51 concentrate or reject stream to its concentration in the feed stream …(3) 4permeate flux: the volumetric rate of flow through unit membrane. ...(4) where s is area of membrane, v is volume of permeate and t is time, hasan [15]. experimental materials two types of dyes were selected: 1. direct yellow 2. direct blue 6 characteristics of these dyes are presented in table (1). solution of dyes (1000 ppm) were prepared by dissolving 1 g of each dye in 1 litter of distilled water and then diluted with distilled water to the required concentration 450, 350, 250, 150, 75 ppm table 1, chemical formula and wavelength at extinction measurement of the dyes examined dyes wave length (nm) structure mw direct yellow 430 c30 h26n4na208s2 680.66 direct blue 6 900 c32 h20n6na4014s4 932.75 experimental procedure reverse osmosis system was installed in the university of baghdad – the chemical engineering department lab. it consists of a vessel for wastewater with dyes which is prepared by adding dyes to distilled water; also there is a micro filter which is used to remove suspended materials, if existed, which is considered as a protector for the reverse osmosis membranes. after the feed water is fed into the micro filter as pretreatment then introduced to the ro membrane which is a spiral-wound module. high pressure pump (maximum pressure 120 psi) used to allow water pass through the thin film composite (tfc) membrane then into the product solution as shown in figure (1). this system is based on the concentration of dye solution as recycled back to the feed vessel to get the highest recovery percentage. fig. 1, reverse osmosis process reverse osmosis polyamide membrane for the removal of blue and yellow dye from waste water 52 ijcpe vol.14 no.2 (june 2013) -available online at: www.iasj.net spectrophotometer with suitable wave length for each dye as shown in table (1) was used to measure the product solution, feed solution and reject dye solution every 15minutes. all experiments were carried out in 2hours to reach steady state conditions. water flux was calculated by dividing the permeate volumes by the membrane area and time (equation 4). at the end of the experiment solution was drained out and the system was washed by distilled water. result and discussion effect of feed concentration by increasing dye feed concentration, this appears as a decrease of water flux through the membrane as shown in figure 2. as the feed concentration increased the product rate decreased. according to the equation 1, recovery is a function of product rate. the increase of product rate will increase the recovery for all parameters studied in the present work and vice versa. figure 3 shows the effect of feed concentration on permeate concentration and reject percentage for blue and yellow dyes respectively. the figure indicate that the permeate concentration increasing when the feed concentration increased. the decrease of permeate concentration will increase the rejection percentage and vice versa (equation 2). the possibility of fouling inside the pores of membrane would be larger in case of the concentrated solution flowing. this fouling could be acting in two ways. first blockage a number of pore completely or partly, so the flow would be decreased, and the second decrease the voidage and that also would be decreased the product rate. as shown in figure 4 the effect of dye feed concentration on concentration of reject and concentration factor, the dye concentrations increases, the reject concentration (or concentrate) will increase. the increasing of reject concentration will increase the concentration factor (equation 3). fig. 2, effect of feed concentration on permeate flow (j) and recovery factor (y %) fig. 3, effect of feed concentration on permeate concentration (cp) and rejection percentage (r %) fig. 4, effect of feed concentration on reject concentration (cret.) and concentration factor (cf) nada mustafa h. al – nakib -available online at: www.iasj.net ijcpe vol.14 no.2 (june 2013) 53 effect of operation temperature the inlet temperature effect on the product rate, increasing temperature will increase the permeate flux and recovery percentage as shown in figure 5. a change in operating temperature will change (i) the densities and viscosities of solutions which increase the relative flow of the pure water through the membrane, (ii) by increasing operating temperature, solute (dye) flux increase, this appears as an increase of solute concentration in the product, and the decreasing of rejection percentage. this is shown in figure 6. the concentrate behavior is shown in figure 7 as a variation of reject concentration and concentration factor increases with increasing temperature. the increasing of temperature means the decreasing of the reject flow rate, which led to an increase in the reject concentration. fig. 5, effect of operating temperature on permeate flow (j) and recovery factor (y %) fig. 6, effect of operating temperature on permeate concentration (cp) and rejection percentage (r %) fig. 7, effect of operating temperature on reject concentration (cret.) and concentration factor (cf) effect of operating time the flow rate from reverse osmosis unit decreases with increase in operating time. the product rate of a reverse osmosis system decrease as fouling occurs, because the foulants on the membrane surface retard the back diffusion of the dye into the bulk solution to cause concentration polarization at the membrane surface. the increase in concentration polarization causes a decrease in the product rate that explain the decreasing of product rate with increase operating time as shown in figure 8. the water recovery and permeate flux decrease with increasing operating time according to equations 1 and 4. figure 9 shows the influence of operating time on rejection percentage. the increases in time cause an increase in fouling of membrane. this reason can be explain the increase dye concentration with increase in operating time which causes the decrease in rejection percentage. figure 10 shows the effect of operating time on concentration of reject and concentration factor for reverse osmosis unit. during the operation, water flux through the membrane decreases, for this reason the concentration of reject solution decrease. so, the reject concentration reverse osmosis polyamide membrane for the removal of blue and yellow dye from waste water 54 ijcpe vol.14 no.2 (june 2013) -available online at: www.iasj.net decreases with time increase. concentration factor decreases according to equation 3. fig. 8, effect of operating time on permeate flow (j) and recovery factor (y %) fig. 9, effect of operation time on permeate concentration (cp) and rejection percentage (r %) fig. 10, effect of operating time on reject concentration (cret.) and concentration factor (cf) conclusion:  reverse osmosis gives a high efficiency in separation dyes. the product rate in ro increases with increasing temperature, but it decreases with increasing feed concentration and operating time.  the increase in operating time, feed concentration and feed temperature will decrease the rejection percentage. the increase in feed concentration and operating time decrease concentration factor while increases in temperature increase it.  the maximum recovery of dye (direct yellow) is 18.32% and for direct blue 6 is 17.84%. the maximum rejection of dye (direct yellow) is 98.30% and for direct blue 6) is 98.89%. the maximum concentration factor of direct blue 6 is 1.227 and for direct yellow is 1.272. references 1. i.petrinic, n.p.raj andersen, s.sostar-turk and a.m.lemorech (2007) the removal of reactive dye printing compounds using nanofiltration. dyes pigments, 74 (3). (515-518) 2. chokrabarti, t. et al., (1988) biodegradation of recalcitrant industrial wastes. biotreatment system, v.ll ed crc press inc. bocaraton florida. 3. manoskovn rachakorakij, sirwan ruangchuay, and sumate teachakulwiroj, (2004) songklanakarin j.sci.technol, 26, (suppl.l) (13-24) 4. m. gholami, s. nasseri, mr. alizadeh fard, a. mesdoghinia, f. veazi, a. mahri, k. naddaffi,iranian j, pub 1 health, vol.30, no.1-2 (7380). 5. a.z.bouy akouba, s, kachaa, b.lartigesb, s.bellebiaa, z.derrichec, (2002) tretment of reactive dye solutions by nada mustafa h. al – nakib -available online at: www.iasj.net ijcpe vol.14 no.2 (june 2013) 55 physicochemicl combined process, 12 (202-209) 6. allen w. prescott w.b., derby r.e( 1973) determination of color water and wastewater by means of admi color ralnes,proc.28 th ind. conf.purdue unive. ,eng ext ser. no 142. (661-668). 7. albanis, t. a hela, d. g. sakallarides, (2000) removal of dyes from equeous solution by adsorption on mixture of fly ash and soil in batch and column techniques, golbal nest; the int, j, vol.2, no.3, (237-244) 8. mohamed al-aseeri, qais bu-ali, shaker haji,nader al-bastaki (2007)removal of acid red and sodium chloride mixtures from aqueous solutions using nanofiltration, desalination 206 (407-413) 9. cheryan, m. 1998 "ultrafiltration and microfiltration handbook", technomic, lancaster, pa. 10. ulrich merten, (1966) desalination by reverse osmosis, the m. j. t .press, (2-4) 11. s.sourirajan 1970 reverse osmosis, logos press limited,(1-5) 12. dan mihal libotean 2007 modeling the reverse osmosis processes performance using artificial neural networks, ph.d thesis, virgili university , tarragona (1-10) 13. liv ffeini zhang guoliang, meng qin and zhang hongzi, (2008) performance of nanofiltration and reverse osmosis membranes in metal effluent treatment, chin .j.chem.eng.vol 16, no.3, june (441-445) 14. l.koyuncu, e.kural and d.topacik, (2001) pilot scale nanofiltration membrane separation for waste management in textile industry, water science and technology, vol.43 no.10 (233240) 15. hasan f. m 2008, investigating polyamide membrane in direct osmosis process in cooling towers, ph.d thesis, baghdad university. available online at https://ijcpe.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.19 no.2 (june 2018) 33 – 37 issn: 1997-4884 corresponding authors: yossor r. abdulmajeed, email: yossor_riadh@yahoo.com, noor al-huda jabber mahmood, email: nalhuda638@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial-noderivatives 4.0 international license production of high surface area activated carbon from grass (imperata) yossor r. abdulmajeed a and noor al-huda jabber mahmood a department of chemical engineering, al-nahrain university, baghdad, iraq abstract in this work the production of activated carbon (ac) from imperata is done by microwave assisted potassium hydroxide (koh) activation and using this activated carbon for the purpose of the uptake of amoxicillin (amx) by adsorption process from aqueous solution. the effects for irradiation power (450-800w), irradiation time (6-12min) as well as impregnation ratio (0.5-1 g/g) on the amx uptake and yield amx uptake at an initial concentration of amx (150 mg/g). the optimum conditions were 700 w irradiation power, 10 min time of irradiation, as well as 0.8 g/g impregnation ratio with 14.821% yield and 12.456 mg/g amx uptake. total volume of hole and the area of the surface (bet) are 0.3027 m³/g, and 552.7638 m²/g respectively. the properties for the activated carbon were examined via scanning electron microscopy (sem). keywords: adsorption, activated carbon , koh accepted on 26/9/2017 1introduction pharmaceutical components are found as wastes in water and have been known as the dangerous chemical matters ‎[1], ‎[2]. lately, amoxicillin was found in hospital waste water ‎[3]. several techniques such as coagulation, biodegradation and chemical oxidation etc., are used for the elimination of antibiotics from wastewater. the process of adsorption have proven to be a well technique, thanks to major advantages like applicability of a large concentration extent of adsorbate, efficient elimination capacity, low equipments price , as well as the existence of much rate-controllable parameters ‎[4],‎[5]. amoxicillin is one of the industrial antibiotic which was high microorganism resistance. amx wastes cause a distasteful odor, lacing condition, and can reason microbe impedance between pathogen organisms or the disease for microorganism that are efficient in wastewater handling. the impedance microorganism might be the reason of sickness which can't be handled via traditional antibiotics. because of those causes, amx has to be compelled to be treated before dislodge to the ambience ‎[6]. activated carbon could be a pored carbon matter that has a high sorption capability which is wide utilized such adsorbent within the filtrate for liquids and gases ‎[7]. some of wide classification is manufactured for popular purposes depend on their physical properties as powder activated carbon (pac) or granular activated carbon (gac). gac is made from a crushed material, granular raw material, or pellets produced from fine raw material and a binder, whereas pac is from crushed or ground carbon particles. the particle size of pac is commonly less than 100 μm; whereas the particle size of gac is commonly around 1 to 5mm. generally, pac is widely used for water treatment. gac is used for adsorption from the gas phase. either pac or gac may be utilized for both gas and liquid phase applications ‎[8]. it is well known that ac may be produced from a great set of net materials with low levels of inorganic compounds and high carbon content. several materials of carbonaceous nature like coal, wood, nutshells, lignite and peat are utilized in the manufacture of commercial activated carbon. gathering and handling of several crops of agricultural materials result in great amounts of agricultural by-products ‎[9]. in the industrial operation of activated carbon, there are two strategies of activation, chemical and physical ‎[10]. microwave heating is more and more used in several scientific fields and technologies for an assortment of implementations, as a result of its feature of uniform heating rate and faster compared with the conventional heating process. the transfer of energy does not depend on the effluent of convection or conduction, however, it is converted into heat inside the particles via rotation of dipole and conduction of ions ‎[11]. 2experimental work and materials 2.1. adsorbate amoxicillin amx (c16h19n3c5s) was utilized as an adsorbate. its molecular weight is 365.4 g/mol. a stock solution of 400 ppm was produced via dissolving a suitable amount for amx in distilled water; it is taken y. r. abdulmajeed and n. j. mahmood / iraqi journal of chemical and petroleum engineering91,2 (2018) 33-37 43 from the arab company for the manufacture of antibiotics and accessories form (akai) and thereafter diluted for the desirable concentrations. 2.2. adsorbent raw materials imperata is utilized for production of activated carbon, it can be re used, it is vastly obtainable, inexpensive as well as ecological amiable resources. it was washed with filtered water to eliminate dust, dehydrated by placing at 80°c for 24h as well as cut to a very small size. then it was sifted into a regular size for (300-1000) µm. potassium hydroxide was employed as a chemical activator. 2.3. activated carbon production weighed quantity (5g) of dried imperata was impregnated with 25 ml from potassium hydroxide solution at several impregnation ratios (ir) (0.5 – 1g/g) of 24 hr in room temperature. the specimens are put in oven at 90°c till fully desiccated thereafter the dried specimens were activated via utilizing a quartz glass column (3cm diameter x 15cm height ). the column was closed at the bottom and open from the top end to allow the run off the vapors that result from pyrolysis. a modified microwave was utilized where a movable overlay linked to a stainless steel tube of 5mm inner diameter from that pyrolysis gases are way out. it is shown in fig. 1. fig. 1 a photographic modified microwave heating oven the column was put inside the microwave and adjusted to several irradiation power (450 – 800w) and several irradiation time (4 – 12 min) are shown in table 1 table 1. activated carbon produced via microwave heating experiment number irradiation time (min) irradiation power(watt) impregnation ratio(gm/gm) 1 6 450 0.8 2 8 450 0.8 3 10 450 0.8 4 12 450 0.8 5 8 450 0.8 6 8 600 0.8 7 8 700 0.8 8 8 800 0.8 9 8 450 0.4 10 8 450 0.5 11 8 450 0.8 12 8 450 1 after activation, the specimen was taken out from microwave to cool. to separate residue potassium hydroxide activator, the specimen was impregnated with hcl solution 0.1m about 10 mg/l activated carbon to hcl solution ratio. the blend was left 24 hours, and then purified and thereafter the specimen was frequently washed with filtered water until eliminating residue alkalis and organic substances and ph of filtrate reached (7-7.5). the specimen was desiccated at 110cº until dry completely. then it was weighed to measure the yield of the activated carbon. the yield of activated carbon produced was determined such as ‎[12]. (1) where wf and wo (g) are the weight of kac and dried imperata, respectively. the amx uptake was determined by following method: 0.1g of the produced ac, with particle size about 300 μm, was placed in 200 ml flask with 100ml for amx sol and primary concentration (150 ppm). those flasks were shaken with 200 rpm to reach equilibrium. after filtration, the concentrations for amx in filtrates were measured using uv -visible spectrophotometer at wavelength about 272nm. the amx uptake, qₑ (mg/g), was measured as follows ‎[13]. (2) where co initial concentration of amx and cₑ (mg/l) equilibrium concentration of amx, respectively, v is the volume of amx solution (l), and w is the weight of activated carbon (g). 3results and discussion 3.1. influence of irradiation time affect irradiation time on the amx uptake and ac yield were performed in constant impregnation ratio 0.8g/g at 450 w irradiation powers. from fig. 2, it is shown that increasing microwave irradiation time from 6 to 10 min displayed a reinforcing of amx uptake from 0.588 to 6.18 mg/g, at 10 min. obviously, lengthened irradiation time leads to lowering of power or temperature, which in turn increases the interaction rates and leads to the opening of holes that caused the extension of the diameter, which will increase porosity of the hole structure ‎[14]. thus, additional heat handling may reproduce local hotspots, leading to the shrinkage and ablation of the activated carbon structure broadening its internal diameter. y. r. abdulmajeed and n. j. mahmood / iraqi journal of chemical and petroleum engineering91,2 (2018) 33-37 43 fig. 2. influence of irradiation time on amoxicillin uptake (at irradiation power 450 w and impregnation ratio 0.8g/g) fig. 3 indicates that the yield for activated carbon decreased with increasing of irradiation time. an increase in irradiation time from 6 to 10 min at 450 w irradiation power and ir of 0.8 g/g leads to an increase the yield from7.6 % to 43.9%, when irradiation time increased from10 to 12 min the yield decreased from 43.9% to 25.6%. a decline decrease happen after 10 min, this is perhaps because of the swift expansion of volatile matter to compose stabilized compounds illustrated by foo and hameed ‎[13]. fig. 3. influence of irradiation time on yield (at ir 0.8 g/g and irradiation power 450 w) 3.2. influence of irradiation power fig. 4 shows that the amx uptake increases with irradiation power about 700 w, thereafter decreased. fig. 4. influence of irradiation power on amx uptake (irradiation time of 8min and ir 0.8g/g) a raise in power from 450 to 700 w at irradiation time 8min and ir of 0.8 g/g causes an increase in amx uptake from 4.2933 to 6.5964mg/g. increasing power from 450 to 700 w resulted in an extravagant raise in amx uptake; which may be attributed to the joint influence of volumetric and internal heating accountable of the extension of the activated carbon structure, build up porosity and a bigger area of the surface ‎[14]. however, at un irradiation power behind 700 w leads to reason the extravagant demolition of hole structures; and a gradual reduction in amx uptake ‎[15]. fig. 5 indicates that as the irradiation power raised from 450 to 800 w at irradiation time (8min) and ir 0.8 g/g, the yield decreased from 18.4 to 8.25%. this may be due to the wastage of the volatile material with raising power. after 700w it was observed that the yield of activated carbon decreased, but at a high irradiation power behind 700 w, gasification may be happen it causing the demolition of hole structures, thus the yield of activated carbon and the amx uptake decreased progressively. the weight wastage of activated carbon raised proportionally to the irradiation power, at most attributable to the strong reaction in a high thermal irradiation which formidable dehydration, putrity, disintegration, and devolatilization ‎[14]. fig. 5. influence of irradiation power on yield (ir 0.8g/g and irradiation time 8) 3.3. influence of impregnation ratio (ir) fig. 6 indicates the impact of ir on amx uptake at irradiation time 8min and irradiation power 450. increasing ir from 0.4 to 1g/g gave rise in amx uptake from 3.7539 to 7.0371mg/g, and thereafter reduction. the potassium ingredient created through the activation stage should spread into the inside structure of impetara and expansion present holes. thence, via rising the proportion of koh to imperata the activation stage should play a major part in hole modeling. the hole was expanded and new micropores mesopores were created in the center pore walls, granting a rise in the total volume of pore and the area of surface. on the other hand the amx uptake was extra improved. the increment of koh and mineral potassium in the surface of activated carbon which leads to clogging of the holes leads to a great decrease in the attainable area. furthermore, an extra increase in ir should increase a strong energizing reaction, it causes to burn off the activated carbon and transformation from micropores-mesopores into macropores decreasing the amx uptake ‎[14]. 0 2 4 6 8 0 5 10 15 a m x u p ta k e ( m g /g m ) irradiation time (min) 0 10 20 30 40 50 0 5 10 15 y ie ld irradiation time (min) 0 2 4 6 8 0 500 1000 a m x u p ta k e ( m g /g m ) irradiation power (w) 0 5 10 15 20 0 200 400 600 800 1000 y ie ld irradaition power (w) y. r. abdulmajeed and n. j. mahmood / iraqi journal of chemical and petroleum engineering91,2 (2018) 33-37 43 fig. 6. influence of ir on amx uptake at irradiation time 8 min and irradiation power 450w) fig. 7 it will be plainly deduced that the yield of activated carbon decreased from 49.06 to 6.75% with raising impregnation ratio (0.4-1 g/g). correspondingly, the increase in impregnation ratio explained a good reduction of the yield of activated carbon. this is agree with results gained by sudaryanto, 2006 ‎[16] for ac production by chemical activation from cassava peel with potassium hydroxide. fig. 7. influence for impregnation ratio on the yield (irradiation power 450w, irradiation time8 min) 3.4. characteristic for ac the most features for ac are total pore volume and specific surface area. the total volumes of pore as well as the area of surface of activated carbon produce at better conditions are 0.3027 m 3 /g and 552.7638m 2 /g, respectively. those results were best compared with of that prepared activated carbon via huda (2016), the area of surface of activated carbon produce from scrap tires via utilizing koh as activation reagent were 374.594 m 2 /g. table 2 shows the comparison of structure textural of prepared activated carbon with carbons from various raw materials. from this table it can be shown that the imperata is known as a suitable raw material for ac with high volume of pores and the high surface area. the chemical energizing operation has participation in the high area of surface and the volume of pore of the activated carbon produced. table 2. compare between pore structures for activated carbons produced from several raw materials raw materials activation bet surface area m 2 /g reference imperata koh 552.7638 this study cotton stalk koh 729.33 deng, et. al.2010 scrap tires koh 374.594 huda 2016 oil palm stone co2 320 guo and lua 2000 bamboo charcoal co2 263 wang et., 2012 3.5. surface morphology the sem images of imperata and kac are displayed in fig. 8 and fig. 9. it will be noted that the imperata surface is planar, intensive, shrunken and plugged by deposited substance. however, the microwave irradiation specimen gave a good expanded and regular surface formation a organized hole structure. the development for porosity of ac by koh activation. it was supposed which koh was decreased to compose mineral potassium through the carbonization operation. the interaction among the carbon and koh happen as follows: 2c + 6koh → 3h2 + 2k2co3 +2k k2co3 was decreased via carbons to compose co, k, co2, and k2o so that many holes were formed: 2c + k2co3 → 3co +2k k2co3→ co2 + k2o it was supposed that mineral potassium formed through the gasification operation would spread into the interior activated carbon matrix structure expansion the existing holes and formed new holes ‎[17]. fig. 9 also indicate which the produced activated carbon surface comprise several chambers that were created from the vaporization of saturated koh leaving the gab already taken via the agent. these gabs supply channels to the micropores and mesopores internal an activated carbon particle. fig. 8. sem micrographs(200µm) of imperata 0 2 4 6 8 0 0.5 1 1.5 a m x u p ta k e ( m g /g m ) impregnation ratio (g/g) 0 10 20 30 40 50 60 0 0.5 1 1.5 y ie ld impregnation ratio (g/g) y. r. abdulmajeed and n. j. mahmood / iraqi journal of chemical and petroleum engineering91,2 (2018) 33-37 43 fig. 9. sem micrographs (200 µm) of ac 4conclusion from this work, it can be concluded that the activated carbon with the area of surface 552.7638m 2 /g as well as the volume of pore 0.3027m 3 /g was produced from imperata by potassium hydroxide microwave heating. amx uptake of 12.456( mg solution /g adsorbent ) with the yield of activated carbon 14.821% were attained in the best condition of irradiation time(10min),irradiation power(700w) as well as ir (0.8g/g).the yield of activated carbon reduced with raising irradiation time, irradiation power and ir . the amx uptake is directly proportional to irradiation time, irradiation power and ir. references [1] chatterjee, r., (2008)," fresh produce from wastewater", environ. sci. technol, 42 (21), 77322008. [2] elsayed, e.m., prasher, s.o. and patel, r.m., (2013)," effect of nonionic surfactant brij 35 on the fate and transport of oxytetra cycline antibiotic in soil", j. environ. manage, 116, 125-134 [3] ghauch, a., tuqan., a., and abou assi, h., (2009)," antibiotic removal from water: elimination of amoxicillin and ampicillin by microscale and nanoscale iron particles environ". pollut, 157,1626– 1635 [4] bajpai, s.k., bajpai, m. and rai, n., (2012)," sorptive removal of ciprofloxacin hydrochloride from simulated wastewater using sawdust: kinetic study and effect of ph afr. j, 38 n° 5", 673-682 [5] zha s.x., zhou y., jin x. and chen z., 2013,"the removal of amoxicillin from wastewater using organobentonite",journal of environmental management 129 ,569,576. [6] aksu z., (2005), application of biosorption for the removal of organic pollutants: a review, process biochemistry, 40, 997-1026. [7] a .mohammad-khah and r. ansari, (2009)," activated charcoal: preparation, characterization and applications", a review article international journal of chemtech research coden( usa): ijcrgg vol.1, no.4, 859-864 [8] bandosz t. j., 2006,"activated carbon surfaces in environmental remediation", 7, t.j. bandosz, ed, oxford, united kingdom ,elsevier. [9] ioannidou o., and zabaniotou a., (2007), "agricultural residues as precursors for activated carbon production –a review" , renewable and sustainable energy review, 11, (2007),1966,(2005). [10] bansal r.c., donnet j.b and stoeckli h.f., (1988)"active carbon", marcel dekker, 9-28285-5376 new york , united states. [11] duan xin-hui , c. srinivasakannan , peng jin-hui , zhang li-bo, zhang zheng-yong, (2011),"preparation of activated carbon from jatropha hull with microwave heating: optimization using response surface methodology", fuel processing technology 92 394–400. [12] marwa ahmed chaied., (2015)," microwaveassisted preparation of activated carbon from phragmites (reed) for antibiotics adsorption", a thesis submitted to the college of engineering of the university of baghdad in partial fulfillment of the requirements for the degree of master of science in chemical engineering [13] foo k.y. and hameed b.h.( 2012c),” porous structure and adsorptive properties of pineapple peel based activated carbons prepared via microwave assisted koh and k2co3 activation", microporous and mesoporous materials ,148 , 191–195 [14] foo k.y. and hameed b.h. (2012a),” potential of jackfruit peel as a precursor for activated carbon prepared by microwave induced naoh activation”, bioresource technology,112 , 143–150. [15] foo k.y. and hameed b.h., (2012b)” textural porosity, surface chemistry and adsorptive properties of durian shell derived activated carbon prepared by microwave assisted naoh activation”, chemical engineering journal,187, 53– 62. [16] sudarynoto y., hartono s. b., irawaty w. and ismadji s., (2006),"high surface area activated carbon prepared from cassava peel by chemical activation", bioresour. technol., 97,734-739. [17] deng h. , li g.x. , yang h.b. , tang j.p., and tang j.y., (2010a), "preparation of activated carbons from cotton stalk by microwave assisted koh and k2co3 activation", journal of chemical engineering,163,373–381. https://pubs.acs.org/doi/full/10.1021/es8024885 https://pubs.acs.org/doi/full/10.1021/es8024885 https://pubs.acs.org/doi/full/10.1021/es8024885 https://www.sciencedirect.com/science/article/pii/s0301479712006196 https://www.sciencedirect.com/science/article/pii/s0301479712006196 https://www.sciencedirect.com/science/article/pii/s0301479712006196 https://www.sciencedirect.com/science/article/pii/s0301479712006196 https://www.sciencedirect.com/science/article/pii/s0269749108006945 https://www.sciencedirect.com/science/article/pii/s0269749108006945 https://www.sciencedirect.com/science/article/pii/s0269749108006945 https://www.sciencedirect.com/science/article/pii/s0269749108006945 https://www.sciencedirect.com/science/article/pii/s0269749108006945 http://www.scielo.org.za/scielo.php?pid=s1816-79502012000500004&script=sci_arttext&tlng=es http://www.scielo.org.za/scielo.php?pid=s1816-79502012000500004&script=sci_arttext&tlng=es http://www.scielo.org.za/scielo.php?pid=s1816-79502012000500004&script=sci_arttext&tlng=es http://www.scielo.org.za/scielo.php?pid=s1816-79502012000500004&script=sci_arttext&tlng=es https://www.sciencedirect.com/science/article/pii/s0301479713005550 https://www.sciencedirect.com/science/article/pii/s0301479713005550 https://www.sciencedirect.com/science/article/pii/s0301479713005550 https://www.sciencedirect.com/science/article/pii/s0301479713005550 https://www.sciencedirect.com/science/article/pii/s003295920400158x https://www.sciencedirect.com/science/article/pii/s003295920400158x https://www.sciencedirect.com/science/article/pii/s003295920400158x http://www.oxinchemistry.ir/wp-content/uploads/2017/05/activated-carbon.pdf http://www.oxinchemistry.ir/wp-content/uploads/2017/05/activated-carbon.pdf http://www.oxinchemistry.ir/wp-content/uploads/2017/05/activated-carbon.pdf http://www.oxinchemistry.ir/wp-content/uploads/2017/05/activated-carbon.pdf http://www.oxinchemistry.ir/wp-content/uploads/2017/05/activated-carbon.pdf https://books.google.iq/books?hl=en&lr=&id=lqd6hxvzjmwc&oi=fnd&pg=pp1&dq=activated+carbon+surfaces+in+environmental+remediation&ots=avnrhk0zab&sig=kkryclezxgyenwxykmyqq-_zy8u&redir_esc=y#v=onepage&q=activated%20carbon%20surfaces%20in%20environmental%20remediation&f=false https://books.google.iq/books?hl=en&lr=&id=lqd6hxvzjmwc&oi=fnd&pg=pp1&dq=activated+carbon+surfaces+in+environmental+remediation&ots=avnrhk0zab&sig=kkryclezxgyenwxykmyqq-_zy8u&redir_esc=y#v=onepage&q=activated%20carbon%20surfaces%20in%20environmental%20remediation&f=false https://books.google.iq/books?hl=en&lr=&id=lqd6hxvzjmwc&oi=fnd&pg=pp1&dq=activated+carbon+surfaces+in+environmental+remediation&ots=avnrhk0zab&sig=kkryclezxgyenwxykmyqq-_zy8u&redir_esc=y#v=onepage&q=activated%20carbon%20surfaces%20in%20environmental%20remediation&f=false https://www.sciencedirect.com/science/article/pii/s136403210600061x https://www.sciencedirect.com/science/article/pii/s136403210600061x https://www.sciencedirect.com/science/article/pii/s136403210600061x https://www.sciencedirect.com/science/article/pii/s136403210600061x https://www.sciencedirect.com/science/article/pii/s0378382010003334 https://www.sciencedirect.com/science/article/pii/s0378382010003334 https://www.sciencedirect.com/science/article/pii/s0378382010003334 https://www.sciencedirect.com/science/article/pii/s0378382010003334 https://www.sciencedirect.com/science/article/pii/s0378382010003334 https://www.sciencedirect.com/science/article/pii/s0378382010003334 https://www.sciencedirect.com/science/article/pii/s138718111100357x https://www.sciencedirect.com/science/article/pii/s138718111100357x https://www.sciencedirect.com/science/article/pii/s138718111100357x https://www.sciencedirect.com/science/article/pii/s138718111100357x https://www.sciencedirect.com/science/article/pii/s138718111100357x https://www.sciencedirect.com/science/article/pii/s0960852412002295 https://www.sciencedirect.com/science/article/pii/s0960852412002295 https://www.sciencedirect.com/science/article/pii/s0960852412002295 https://www.sciencedirect.com/science/article/pii/s0960852412002295 https://www.sciencedirect.com/science/article/pii/s1385894712001027 https://www.sciencedirect.com/science/article/pii/s1385894712001027 https://www.sciencedirect.com/science/article/pii/s1385894712001027 https://www.sciencedirect.com/science/article/pii/s1385894712001027 https://www.sciencedirect.com/science/article/pii/s1385894712001027 https://www.sciencedirect.com/science/article/pii/s0960852405002142 https://www.sciencedirect.com/science/article/pii/s0960852405002142 https://www.sciencedirect.com/science/article/pii/s0960852405002142 https://www.sciencedirect.com/science/article/pii/s0960852405002142 https://www.sciencedirect.com/science/article/pii/s1385894710007242 https://www.sciencedirect.com/science/article/pii/s1385894710007242 https://www.sciencedirect.com/science/article/pii/s1385894710007242 https://www.sciencedirect.com/science/article/pii/s1385894710007242 https://www.sciencedirect.com/science/article/pii/s1385894710007242 iraqi journal of chemical and petroleum engineering vol.14 no.3 (september 2013) 4954 issn: 1997-4884 permeability prediction in carbonate reservoir rock using fzi hussain ali baker, sameer noori al-jawad * and zainab imad murtadha petroleum engineering department, college of engineering, university of baghdad * ministry of oil/ department of reservoir field development abstract knowledge of permeability, which is the ability of rocks to transmit the fluid, is important for understanding the flow mechanisms in oil and gas reservoirs. permeability is best measured in the laboratory on cored rock taken from the reservoir. coring is expensive and time-consuming in comparison to the electronic survey techniques most commonly used to gain information about permeability. yamama formation was chosen, to predict the permeability by using fzi method. yamama formation is the main lower cretaceous carbonate reservoir in southern of iraq. this formation is made up mainly of limestone. yamama formation was deposited on a gradually rising basin floor. the digenesis of yamama sediments is very important due to its direct relation to the porosity and permeability. in this study permeability has been predicated by using the flow zone indicator methods.this method attempts to identify the flow zone indicator in un-cored wells using log records. once the flow zone indicator is calculated from the core data, a relationship between this fzi value and the well logs can be obtained. key words: permeability, fzi introduction one of the most important rock parameters for the evaluation of hydrocarbon reservoirs is permeability. permeability was controlled by the size of the connecting passage between pores. recovery of hydrocarbons from the reservoir is an important process in petroleum engineering and estimating permeability can aid in determining how much hydrocarbons can be produced from a reservoir. tiab and donaldson [1] gives that the nature of reservoir rocks containing oil dictates the quantities of fluids trapped within the void space of these rocks. the measure of the void space is defined as the porosity of the rock, and the measure of the ability of the rock to transmit fluids is called the permeability. knowledge of these two properties is essential before questions concerning types of fluids, amount of fluids, rates of fluid flow, and fluid recovery estimates can be answered. pasternak [2] estates that there are methods for measuring porosity and permeability have comprised much of the technical literature of the oil industry. there is no specific correlation between permeability and porosity values. in many cases the relationship between permeability and porosity is qualitative and is not directly or indirectly quantitative in iraqi journal of chemical and petroleum engineering university of baghdad college of engineering permeability prediction in carbonate reservoir rock using fzi 50 ijcpe vol.14 no.3 (september 2013) -available online at: www.iasj.net any way. it is possible to have very high porosity without having any permeability at all, as in the case of pumice stone (where the effective permeability is nearly zero), clays and shales. the reverse of high permeability with a low porosity might also be true, such as in microfractured carbonates. in spite of this fundamental lack of correspondence between two properties, there often can be found a useful correlation between them within one formation flow units bear [3] defined the flow unit as the representative elementary volume of the total reservoir rock within which the geological and petrophysical properties of the rock volume are the same. hear et al. [4] defined the flow unit as a reservoir zone that is laterally and vertically continuous, and has similar permeability, porosity, and bedding characteristic. ebank [5] defined the hydraulic flow unit as a map-able portion of the reservoir within which the geological and petrophysical properties that affect the flow of fluid are consistent and predictably different from the properties of other reservoir rock volume. gunter et al. [6] defined the flow unit as a stratigraphically continuous interval of similar reservoir process that honors the geologic framework and maintains the characteristic of the rock type. the concept of hydraulic flow units can be used to predict permeability with reliable accuracy. development of flow unit concept amaefule et al. [7] considered the role of the mean hydraulic radius in defining hydraulic flow units and correlating permeability from core data. their approach was essentially based on a modified kozeny-carmen equation: ( ) ( ) the amaefule et al. [7] approaches were essentially based on a modified kozeny-carmen equation coupled with the concept of mean hydraulic radius: tiab and donaldson [1] considered the concept of sub-grouping reservoir volume into flow units, suggests that the term in eq. (1), which is classically referred to as kozeny constant, is actually “variable constant”. this means that kozeny constant may vary for different hydraulic units, but is constant for a specific unit. based on that, tiab and donaldson [1] introduced the “variable constant” referred to as the effective zoning factor: ( ) ( ) tiab and donaldson [1] proposed to estimate the effective zoning factor: carmen [8] simulated a porous medium as a bundle of capillary tubes. they combined darcy’s law for flow in a porous medium and poiseuille’s law for flow in tubes. a tortuosity factor was also included, because for a realistic model of porous media the connected pore structure is not straight capillary tubes. carmen [8] suggested the following relationship between porosity and permeability: hussain ali baker, sameer noori al-jawad and zainab imad murtadha -available online at: www.iasj.net ijcpe vol.14 no.3 (september 2013) 51 ( ) al –ajmi and holditch [9], the mean hydraulic radius can be related to the specific surface area per unit grain volume , and the effective porosity , by the following equation: ( ) combining equations (5) and (6), gives the generalized kozeny –carmen equation: the term is known as the kozeny constant, which is usually between 5 and 100 in most reservoir rocks. the term a function of geological characteristics of porous media and varies with changes in pore geometry. the determination of the ( ) group is the focal point of the hydraulic flow unit (hfu) classification technique. identification of flow zone indicator (fzi) and reservoir quality index (rqi) taslimi [10], flow zone indicator depends on geological characteristics of the material and various pore geometry of a rock mass; hence, it is a good parameter for determining hfu. flow zone indicator is a function of reservoir quality index and void ratio. amaefule et al. [7] addressed the variability of kozeny’s constant by dividing eq. (1) by the effective porosity, and taking the logarithm: √ ( ) √ where, the constant 0.0314 is the permeability conversion factor from μm 2 to md. al –ajmi and holditch [9] defined the flow zone indictor fzi (μm) as: √ reservoir quality index rqi (μm) as: √ and normalized porosity (fraction) as: eq. (8) becomes: taking the logarithm of both sides of eq. (12) yields: al –ajmi and holditch [9] considered that in a log-log plot of rqi versus all the samples with similar fzi values lie on a straight line with a slope of one; and data samples with the same fzi values, but significantly different from the preceding one, will lie on another, parallel, unit-slope lines; and so on perez [11]. samples that lie on the same straight line have similar pore throat attributes, and thereby constitute a unique hfu. each line represents a hfu and the intercept of this line with is the mean fzi value for that hfu. each flow unit permeability prediction in carbonate reservoir rock using fzi 52 ijcpe vol.14 no.3 (september 2013) -available online at: www.iasj.net is characterized by fzi. amaefule et al. [7] determined the basis of hfu classification is to identify groups of data that form unit-slope straight lines on a log-log plot of rqi versus , as shown in fig. (1). fig. 1, reservoir quality index vs. normalized porosity, murtadha [13] fzi correlation with well logs fzi is then correlated with certain combinations of logging tool responses to predict permeability values in cored and un-cored intervals of wells. this method attempts to identify the flow zone indicator in un-cored wells using log records. once the flow zone indicator is calculated from the core data, a relationship between this fzi value and the well logs can be obtained, (pablo [12]). al –ajmi and holditch [9] showed that to calculate permeability in un-cored wells, correlations were developed between well log measurements and fzi values from core data using two statistical ways; parametric method or non-parametric transformation of variables regression. the fzi is then correlated with certain combinations of logging tool responses to develop regression models for permeability predictions in cored and un-cored intervals or wells, (amaefule et al. [7]). equations (10) through (12) are used to compute the functions for preparing a log-log plot of versus for each reservoir unit of all the wells. the data that have similar fzi values fall on a straight line (of the same slope); and all the data on the same straight line can be considered to have similar pore throat attributes (the same hydraulic unit) governing the flow. the permeability can be computed for those points on the same straight line (with same fzi) as shown in fig. (2): fig. 2, core permeability vs. core porosity, murtadha [13] using the eq. (14) to calculate the permeability in the uncored wells: ( ) fig. (3) represents k–predicted by fzi vs. k–core and fig. (4) represent k– predicted by fzi and k–core vs. depth. fig. 3, k-predicted by fzi versus k-core, murtadha [13] hussain ali baker, sameer noori al-jawad and zainab imad murtadha -available online at: www.iasj.net ijcpe vol.14 no.3 (september 2013) 53 fig. 4, k–predicted by fzi and k–core vs. depth, murtadha [13] conclusions  fzi method is very accurate method in estimating permeability in uncored well. good agreement has been obtained between core permeability and calculated permeability by fzi method.  fzi method gave three groups for yamama reservoir, each group represent type of rocks, each type have the similar porosity and similar properties which can be used to divide the reservoir. nomenclature symbol description unit fs effective pore throat shape factor (---) k permeability md function of pore-pore throat size and geometries, tortuosity and cementation (---) r pore throat radius µm rah mean hydraulic radius µm surface area of grains exposed to fluid per unit volume of solid material cm 2 /cm 3 greek symbols effective porosity fraction hz normalized porosity fraction tortuosity (---) abbreviations fzi flow zone indicator hfu hydraulic flow unit rqi reservoir quality index references 1djebbar tiab, and erle c. donaldson, (2004), “petrophysics; theory and practice of measuring reservoir rock and fluid transport properties”, 2 nd edition, gulf professional publishing, elsevier, inc. 2elena pasternak, (2009), “porosity– permeability relationship”, allan hancock college. 3bear, j. (1972), “dynamics of fluids in porous media”. elsevier, new york. 4hear, c. l., ebanks, w. j., tye, r. s. and ranganatha, v., (1984), permeability prediction in carbonate reservoir rock using fzi 54 ijcpe vol.14 no.3 (september 2013) -available online at: www.iasj.net “geological factors influencing reservoir performance of the hartzog draw field, wyoming”, j. of petrol. tech, aug. 5ebanks, w. j., (1987), “the flow unit concept-an integrated approach to reservoir description for engineering projects”, am. assoc. geol. annual convention. 6gunter, g. w., finneran, j. m., hartman, d. j. and miller, j. d., (1997), “early determination of reservoir flow units using an integrated petrophysical method”, spe 38679. spe annual technical conference and exhibition, san antonio, tx. 7jude o. amaefule, mehmet altunbay, djebbar tiab, david g. kersey and dare k. keelan, (1993), “enhanced reservoir description: using core and log data to identify hydraulic (flow) units and predict permeability in uncored intervals/ wells”, spe, houston, texas. 8carmen, p.c. (1937), “fluid flow through granular beds”, trans. aiche, v.15. 9fahad a. al-ajmi, stephen a. holditch, (2000), “permeability estimation using hydraulic flow units in a central arabia reservoir”, saudi aramcoschlumberger, spe. 10m. taslimi, b. bohloli, e. kazemzad, and m.r. kamali, (2008), “determining rock mass permeability in a carbonate reservoir, southern iran using hydraulic flow units and intelligent systems”, school of geology, college of science, university of tehran, research institute of petroleum technology, n.i.o.c., tehran, iran, 2nd iasme / wseas international conference on geology and seismology (ges '08), cambridge, uk 11hector h. perez, akhil datta – gupta, (2003), “the role of electrofacies, lithfacies, and hydraulic flow units in permeability predictions from well logs: a comparative analysis using classification trees”, texas aandm u. and s. mishra, spe. 12lacentre e. pablo and carrica m. pablo, (2008), “a method to estimate permeability on uncored wells: the method, based on cores and log data, has been shown to outperform standard-regression techniques, as well as the hydraulicflow-unit approach”, cengage learning. 13zainab imad murtadha, (2012), “reservoir evaluation of yamama formation of ratawi oil field”, m.sc. thesis, petroleum engineering department, university of baghdad. iraqi journal of chemical and petroleum engineering vol.15 no.1 (march 2014) 4350 issn: 1997-4884 estimation liquid permeability using air permeability laboratory data jalal abdulwahid al-sudani, rwaida kaiser and salam j. al-rubeai * college of engineering-university of baghdad * university of oklahoma abstract permeability data has major importance work that should be handled in all reservoir simulation studies. the importance of permeability data increases in mature oil and gas fields due to its sensitivity for the requirements of some specific improved recoveries. however, the industry has a huge source of data of air permeability measurements against little number of liquid permeability values. this is due to the relatively high cost of special core analysis. the current study suggests a correlation to convert air permeability data that are conventionally measured during laboratory core analysis into liquid permeability. this correlation introduces a feasible estimation in cases of data loose and poorly consolidated formations, or in case of the unavailability of old cores to carry out liquid permeability. moreover, the conversion formula offers a better use of the large amount of old air permeability data obtained through routine core analysis for the further uses in reservoir and geological modeling studies. the comparison analysis shows high accuracy and more consistent results over a wide range of permeability values for the suggested conversion formula. keywords: air permeability; liquid permeability introduction nowadays, all the reservoir studies that are based on reservoir simulation technique requires a huge source of permeability data, which is always difficult to obtain, and may not be available at all [1]. therefore, the engineers are forced to assume values of liquid permeability data based on a limited number of core laboratory analysis. the conversion of air permeability to liquid permeability forms a cost effective method for coring [1]. however, the routine core analysis that is usually performed through the exploratory stage of the field development provides a huge data of air permeability. this analysis may serve for estimating the liquid permeability if using higher degree of correlation. the correlative approach appears to be the best practical method of estimating liquid permeability data [2]. ideally, those data should be obtained experimentally. occasionally, these data are not either available or reliable; then, empirically derived iraqi journal of chemical and petroleum engineering university of baghdad college of engineering estimation liquid permeability using air permeability laboratory data 44 ijcpe vol.15 no.1 (march 2014) -available online at: www.iasj.net correlations are used to predict the liquid rock permeabilities. however, the success of such correlations in prediction depends mainly on the range of data at which they were originally developed. these data were divided into two groups: the first was used to cross validate the relationship established during the training process and, the second was used to test the model to evaluate their accuracy and trend stability. the current study tries to fit the relationship between air permeability and liquid permeability for iraqi reservoirs into a mathematical form to make use of the available air permeability data; in addition to generalize the suggested correlation for a wide range of fields. data acquisition and analysis the developed correlation is based on 446 field data sets collected from different wells in khasib formation of iraqi oil fields [3], in addition to 12 data sets collected from some fields in egypt (nubia c, october, ramadhan, east tanka, hilal, gebel el-ziet and ras-burdan) [1]. each data set contains depth, air permeability, liquid permeability, water saturations and porosity. these iraqi data were divided into two groups. the first one (386 sets) was used to cross-validate the relationship established during the training process and, the second group which consist of (60 sets) were used to test the correlation to evaluate their accuracy and trend stability; in addition to use the other (12) data sets of air permeability that are collected from egyptian oil fields to conduct the evaluation of the suggested empirical correlation for more validation of generalization. the range of collected permeability data falls between (0.004 to 409 md) for iraqi wells which consist of (168 data points less than unity and 276 data points greater than unity) in addition to (12 data points) having liquid permeability range (7 to 3000 md) collected from the egyptian oil fields; this wide range of the data offers high reliability of the suggested correlation. work development the work development could be achieved throughout suggesting a conversion formula that is dimensionally pass the physics, gives minimum absolute errors and obey the assumptions reservoir coring analysis; these statement can be summarize as follows. 1statistical error analysis statistical error analysis is performed to compare the performance and accuracy of the new model to the laboratory data. average absolute percentage relative error, minimum and maximum absolute error, root mean square and standard deviation were used as comparison criteria. 2assumption although the volume of the cored intervals representing an infinitesimal area when compared to the reservoir itself, it is important to assume that the sample is accurately represent the formation within the drainage area of the well; i.e. the core analysis data provide a true distribution function for the permeability. 3conversion formula the suggested form of the conversion formula should first maintain the physics before the trails that could be made to find the best fitness. the physics of the conversion formula should involve the formation porosity as major dependable factor effects on both of air and liquid permeabilities. jalal abdulwahid al-sudani, rwaida kaiser and salam j. al-rubeai -available online at: www.iasj.net ijcpe vol.15 no.1 (march 2014) 45 moreover, both sides of the suggested formula must obey the dimensional physics. however, this suggestion may provide the reliability for the proposed correlation than that is already used in the literature (sameh m. macary-1999) that is ignore the porosity and use only an adjustable constants between the liquid and air permeabilities to fit the conversion formula. therefore, the suggested formula can be written using the following form; …(1) where; and are the air and liquid permeabilities respectively in millidarcy (md). a, b and c are constants to fit the correlation with the actual data measurements; and is the core porosity. hence, adding the parameter of porosity gives the suggested equation the reliability due its direct effect on permeability [4]. several ways have been adapted to create the most accurate conversion formula; these ways can be categorized as follows; 1deal with all-data points of air permeability variation as one group. 2explicit the data points into some groups depending on the range of air permeability. 3find relation for (a, b and c) constants as function of air permeability or porosity. it is found that the last two categories are the best ways that can be used to create the most accurate conversion formula than the first category. therefore, the experimental air permeability data have been divided into some groups depending on their air permeability data ranges. the trail procedure of regression analysis for the collected trained data points shows that the best value of porosity power (c) which gives the minimum absolute and percentage relative errors for the predicted liquid permeability is (c = 0.09) as shown in figure 1; this value has been obtained throughout extensive trails to gather all liquid permeability data along the 45 degree slope line that is indicating the perfect agreement between the experimental and estimated liquid permeability data. while, it is found that further fitness can be achieved which offers the highest degree of accuracy and consistency can be taken (a = 0.73) for air permeability values less than (1 md) and (a = 1.002) for air permeability values greater than (1 md). meanwhile, the constant (b) is fixed to unity in order to fix the dimensional units of the suggested formula and to ensure its reliability for a wide range of permeability data. thus, equation 1 can be rewritten as follows. …(2) where (a = 0.73) for air permeability values less than unity, and (a = 1.002) for air permeability values greater than unity. the values of (a) gives the best corrections for the slippage and inertial effect that is most significant in low permeability cores [5]. equation 2 represents the most accurate conversion formula to convert air permeability data to liquid permeability. finally, it could be stated that other trails have been made to relate (a and b) parameters to be a function of either air permeability or porosity that keeps the exact fitness between estimated and experimental data for any range of permeability. these trails show no reliable dependence for (a and b) parameters to be a function of either air permeability or porosity. therefore, the suggested model represented by eq. 2 can be considered the best conversion formula to estimate the liquid estimation liquid permeability using air permeability laboratory data 46 ijcpe vol.15 no.1 (march 2014) -available online at: www.iasj.net permeability using that of air laboratory data. results and discussion figures 2 and 3 were obtained for air permeability data less and greater than unity respectively, illustrate scatter diagrams of the predicted versus laboratory data. these cross plots indicates the degree of agreement between the laboratory and predicted values. if the agreement is perfect, then all points should lie on the 45 degree line on the plot. these cross plots show tightest cloud of points around the 45 degree line indicating the high reliability and accuracy of the suggested conversion formula to estimate the liquid permeabilities using air permeability laboratory data. the deviation from the 45 degree straight line did not exceed (0.5 %) between estimated and experimental data of liquid permeabilities. moreover, figures 4, 5, 6, 7 and 8 drawn between air and liquid permeabilities for each well individually. while, figure 9 drawn for all data points collected from all wells and shows the maximum deviation from the 45 degree straight line did not exceed (2.3 %) between estimated and experimental data of liquid permeabilities. in order to check the validity and the accuracy of the conversion formula, the liquid permeabilities measured for the 60 core samples collected from different iraqi wells and that of 12 core samples collected from egyptian oil reservoirs were compared with calculated values generated by equation 2. hence, figures 10 and 11 show the tests that have been made for samples representing wide range of permeability variation (not enter to train the model) show also the extremely high results provided by the suggested model. while, the tests performed for the samples collected from different egyptian fields show also the acceptable results compared with that experientially obtained liquid permeability data. these tests have also been stated in tables 1 and 2 to show the absolute and percentage relative errors for these samples. these tables show the existence of somewhat higher percentage absolute errors (5-30%) in samples no. 3, 14, 37 and 38; however, this variance occur only in some very low permeability samples; since, the absolute percentage errors occurs will also be very low and may not have a significant effect on such low permeability samples. however, figure 12 shows the clear behavior between the calculated and experimental laboratory data for all of the tested core samples. this may assist to support the high reliability and consistency of the suggested model for estimating liquid permeability using the laboratory air permeability data. conclusions the suggested conversion formula can be used to estimate the liquid core permeability using air permeability core data that is part of routine core analysis in reservoir simulation studies. this formula may give a cost effective method for coring. references 1sameh m. macary “conversion of air permeability to liquid permeabilities extracts huge source of information for reservoir studies” spe-53113, this paper was prepared for presentation at the 1999 spe middle east oi show held in bahrain 20-23 feb. 1999. 2jairam kamath “evaluation of accuracy of estimating air permeability from mercury injection data”, spe formation evaluation, dec.1992, pp.304-10. jalal abdulwahid al-sudani, rwaida kaiser and salam j. al-rubeai -available online at: www.iasj.net ijcpe vol.15 no.1 (march 2014) 47 3“the detailed reservoir study for khasib formationahdeb fieild”; reservoir and fields development directorateministry of oil, iraq. 2012. 4shouxiang m.a. and norman r. morrow, “relationships between porosity and permeability”1996 sca conference paper no. 9710. 5j.a. rushing, k.e. newsham, p.m. lasswell, j.c. cox, and t.a. blasingame, ”klinkenberg corrected permeability measurements in tight gas sand; steasy state versus unsteady state techniques” spe-89867, sep. 2004. fig. 1, percentage error against porosity power (b) between estimated and experemental liquid permeability data fig. 2, experimental versus estimated liquid permeability (156 samples) fig. 3, experimental versus estimated liquid permeability (230 data point) fig. 4, experemental versus estimated liquid permeability-well ad/2, (52 points) fig. 5, experemental versus estimated liquid permeability well ad/3), (110 points) fig. 6, experemental versus estimated liquid permeability-well ad/5, (39 points) estimation liquid permeability using air permeability laboratory data 48 ijcpe vol.15 no.1 (march 2014) -available online at: www.iasj.net fig. 7, experemental versus estimated liquid permeability -well ad/6, (114 points) fig. 8, experemental versus estimated liquid permeability-well ad/7, (71 points) fig. 9, experemental versus estimated liquid permeability-wells ad/2,3,5,6,7(386 points) fig. 10, experemental versus estimated liquid permeability-wells ad/2,3,5,6,7; (60 points) fig. 11, experemental versus estimated liquid permeability data (12 data points) fig. 12, the agreement between the calculated and experemental liquid permeability jalal abdulwahid al-sudani, rwaida kaiser and salam j. al-rubeai -available online at: www.iasj.net ijcpe vol.15 no.1 (march 2014) 49 table 1, comparison between laboratory and calculated liquid permeability data shows the percentage absolute relative errors and the absolute errors for iraq field measured. ka md lab. (kl)-md; calculated (kl); md percent relative error absolute error 6.9 0.238 5.2 5.116554 1.630903 0.083446 5.1 0.189 3.8 3.621115 4.940042 0.178885 158 0.226 142 147.4854 3.719274 5.485386 34 0.233 28 28.36121 1.2736 0.361208 23.7 0.247 20 19.34283 3.397476 0.657168 64.2 0.2 55 55.40076 0.723382 0.400759 6 0.283 4.5 4.471943 0.627407 0.028057 4.4 0.255 3.3 3.174118 3.965881 0.125882 5.6 0.242 4.2 4.094194 2.584304 0.105806 12.8 0.184 10 9.714203 2.942051 0.285797 25 0.188 21 19.98861 5.059836 1.011391 8.4 0.209 6.5 6.247931 4.034431 0.252069 157 0.213 141 145.7032 3.227945 4.70322 317 0.271 287.5 317.5496 9.462975 30.04964 8.6 0.235 6.6 6.47597 1.91524 0.12403 11.6 0.265 9 9.030407 0.336719 0.030407 9.3 0.302 7.2 7.205144 0.071391 0.005144 13.6 0.226 11 10.56202 4.146754 0.437981 18 0.233 15 14.31538 4.78242 0.684621 4.7 0.241 3.5 3.390077 3.242486 0.109923 7 0.208 5.3 5.133682 3.239743 0.166318 6.4 0.244 4.8 4.729676 1.486861 0.070324 16.3 0.215 13 12.74923 1.966946 0.25077 4 0.226 2.9 2.834047 2.327152 0.065953 2.3 0.219 1.6 1.558907 2.636002 0.041093 8.8 0.072 6.8 5.967627 13.94814 0.832373 9.7 0.06 7.5 6.518326 15.06021 0.981674 4.4 0.269 3.3 3.189424 3.466974 0.110576 11.3 0.203 8.8 8.5715 2.665811 0.2285 75.8 0.181 66 65.63845 0.550818 0.361548 77.3 0.166 69 66.51591 3.734579 2.484089 3.10 0.145 2.2 2.074016 6.074374 0.125984 3.1 0.218 2.2 2.147819 2.429468 0.052181 2.62 0.212 1.9 1.787998 6.264114 0.112002 4.54 0.221 3.3 3.240807 1.826481 0.059193 2.53 0.198 1.8 1.711502 5.17081 0.088498 280 0.208 260.2 271.0047 3.9869 10.80469 409 0.14 379.2 392.9209 3.492037 13.72095 4.24 0.233 3.1 3.025542 2.46098 0.074458 3.8 0.102 2.8 2.496688 12.14858 0.303312 2.84 0.165 2 1.906398 4.909874 0.093602 7.92 0.23 6.1 5.915724 3.115013 0.184276 1.69 0.167 1.2 1.092309 9.859014 0.107691 1.95 0.214 1.4 1.302709 7.468387 0.097291 1.51 0.246 1 1.002091 0.208681 0.002091 3.95 0.215 2.9 2.783455 4.187064 0.116545 12.6 0.224 10.9 9.721729 12.11997 1.178271 53.1 0.21 45 45.37318 0.822466 0.373179 0.4 0.221 0.24 0.241236 0.51486 0.001236 0.31 0.235 0.19 0.184448 2.921893 0.005552 0.27 0.240 0.17 0.15933 6.276623 0.01067 0.21 0.211 0.13 0.120208 7.532528 0.009792 0.09 0.195 0.05 0.049137 1.726427 0.000863 0.13 0.201 0.07 0.071464 2.091159 0.001464 0.11 0.118 0.07 0.058581 16.31215 0.011419 0.20 0.213 0.12 0.114742 4.381836 0.005258 0.06 0.041 0.03 0.027939 6.871614 0.002061 0.31 0.171 0.19 0.179232 5.667447 0.010768 0.27 0.155 0.17 0.153136 9.919934 0.016864 0.09 0.065 0.05 0.043471 13.057 0.006529 average percentage error 5.00 % estimation liquid permeability using air permeability laboratory data 50 ijcpe vol.15 no.1 (march 2014) -available online at: www.iasj.net table 2, comparison between laboratory and calculated liquid permeability data shows the percentage absolute relative errors and the absolute errors for egypt field measured. ka (md) lab. (kl)-md; calculated (kl); md percent relative error absolute error 1275.9 0.189 1150.73 1100.499 4.3653 50.2334 160.00 0.185 122.714 137.6908 12.204 14.976 408.43 0.153 337.728 345.625 2.338 7.89619 48.72 0.166 34.1326 41.5305 21.674 7.39782 52.273 0.174 36.8030 44.7488 21.59 7.94586 1950.7 0.166 1821.34 1662.891 8.7 158.456 2497.4 0.152 2379.81 2112.149 11.2474 267.668 1147.0 0.168 1027.14 978.8515 4.7016 48.2917 1169.2 0.21 1046.08 1018.049 2.6805 28.0399 146.24 0.189 111.396 126.1341 13.23 14.7378 391.34 0.176 322.041 335.370 4.139 13.3287 309.07 0.183 249.605 265.8004 6.488 16.1952 average percentage error 4.16 % iraqi journal of chemical and petroleum engineering vol.16 no.4 (december 2015) 2129 issn: 1997-4884 reducing of corrosion rate in boiler tubes by using oxygen scavengers saad a jafar and mohammed i fathi chemical engineering department college of engineering –university of tikrit abstract the corrosion distilled water and after adding three types of oxygen scavengers hydroquinone, ascorbic acid and monoethanolamine in different concentrations 40,60 and 80 ppm has been investigated using weight loss method. the carbon steel specimens were immersed in water containing 8.2 ppm dissolved oxygen (do) by using autoclave. it was found that corrosion behavior of carbon steel was greatly influenced by temperature with high pressure. the corrosion rate decreases, when adding any one of oxygen scavengers. the best results were obtained at a concentration of 80 ppm of each scavenger. it was observed that hydroquinone is the best among the other scavengers in reducing the corrosion rate at the temperatures and pressures of this investigation and most efficient in the consumption of oxygen especially 80 ppm, it reduces the concentration of oxygen in water from 8.2 to 0.8 ppm, while the ascorbic acid reduces the oxygen concentration to 1.4 and monoethanolamine reduces the concentration of oxygen to 1.9 . it has been observed that hydroquinone reacts with oxygen quickly and at low temperatures while the other scavengers react slowly with oxygen. key words: boiler feed water (bfw), boiler tubes, dissolved oxygen (do), oxygen corrosion, oxygen scavengers. introduction boiler tubes are constructed primarily of carbon steel to improve its mechanical properties in order to withstand extreme operating pressure and temperature and the medium for heat transfer is water, the potential for corrosion is high. the corrosion of boiler is divided into internal corrosion (water side) and external corrosion (fire side). there are also a number of locations in a boiler system where various types and amounts of corrosion occur. [1] waterside corrosion is a major problem in steam generation systems causing damage, inconvenience, down time, replacements and consequent financial losses every year. the corrosion can take place in pre-boiler, feed water systems, boiler drums & tubes and post boiler system comprising of steam and condensate equipment piping. the cause of water side corrosion is primarily due to the presence of dissolved oxygen and carbon dioxide. the presence of dissolved oxygen is found as key cause of feed water, boiler water and even condensate corrosion in boiler system whereas iraqi journal of chemical and petroleum engineering university of baghdad college of engineering reducing of corrosion rate in boiler tubes by using oxygen scavengers 22 ijcpe vol.16 no.4 (dec. 2015) -available online at: www.iasj.net carbon dioxide is known to cause corrosion in return line condensate system. [2] the most harmful of the dissolved gases in water is oxygen. it is present in all water supplies, though at widely varying concentrations. oxygen is highly corrosive when present in hot water. even small concentrations can cause serious problems. because pits (small but deep pinpoint holes) which is the most common type of corrosion in boilers can penetrate deep into the metal. additionally, iron oxide generated by the corrosion can produce iron deposits in the boiler. for that matter any system that is exposed to dissolved oxygen is under threat. hence it is essential to know this threat well in advance and accordingly try to minimize. water can contain up to (9) ppm dissolved oxygen (do) at room temperature and atmospheric pressure. as the temperature increases, the solubility of oxygen decreases, but water under pressure can hold higher amounts of dissolved oxygen. [3] oxygen corrosion occurs through an electrolytic process (electrochemical reaction ) using the boiler system metal (usually iron) as current path and boiler water as an electrolyte. in this reaction the iron is oxidized (anodic reaction) and released into the water. the electrons from oxidation released and absorbed by dissolved oxygen (cathodic reaction).the reaction is: [4] anodic reaction: f → f +2 + … ( ) cathodic reaction: ½ o2 + h2o + 2e → oh … ( ) electrochemical reaction: fe + ½ o2 + h2o → f (oh)2 ... (3) to control the corrosion due to oxygen, the feed water should be free from oxygen. various methodologies were adopted to remove the dissolved oxygen from boiler water and steam systems. to reduce corrosive dissolved gases from makeup water most plants use some variation of a deaerator. the removal of dissolved oxygen is not complete in this process and the residual dissolved oxygen is normally about (0.007) ppm. this low concentration can influence the corrosion. the residual dissolved oxygen in water can be removed by using chemical agents called oxygen scavengers, which are reducing agents such as sodium sulfite (na2so3), hydrazine (n2h4), hydroquinone(hq) diethylhydroxyl-amine (deha), (c6h4(oh)2, methylethylketoxime (meko) and other chemical compounds that can control (do). it is of critical importance to select and properly use the best chemical oxygen scavenger for a given system. [5] three oxygen scavengers (hydroquinone, ascorbic acid and monoethanolamine) were selected. these compounds tested for the first time in iraq. hydroquinone (hq) hydroquinone is an aromatic compound derived from phenol. it is a crystalline powder. it is well known for its antioxidant properties. its chemical name is (benzene-1,4-diol) and its molecular formula is (c6h6o2). the structure of hydroquinone is shown below: [6] saad a jafar and mohammed i fathi -available online at: www.iasj.net ijcpe vol.16 no.4 (dec. 2015) 23 autoclave studies have shown that the first stage reaction with oxygen is: the benzoquinone subsequently undergoes further reaction with dissolved oxygen. ascorbic acid ascorbic acid (also known as vitamin c) is a naturally occurring organic compound with antioxidant properties. its formula is (c6h8o6) and its structure is shown below. the stoichiometric equation of the reaction between ascorbic acid and dissolved oxygen in water is: [8] c6h8o6 + 1/2o2 → 6h6o6 + h2o ethanolamine there are three types of ethanol amine, monoethanolamine (mea), diethanolamine (dea) and triethanolamine (tea). in this research monoethanolamine was tested for the firsttime as oxygen scavenger. monoethanolamine molecular formula is (c2h7no) and its structure is shown below: it is an important to understand the kinetics of the reaction of (o2) with the amine. the general equation is: [9] mea+ υo2 → nh3 + degradation products experimental setup a schematic diagram of the experimental set up is shown in fig.(1).the cylindrical autoclave, had a wall thickness of approximately 5 mm, heating tape surrounded the outside the autoclave, temperature controller, pressure gauge recorder, n2 gas cylinder, sensor record temperature and control valve to get rid of excess steam. maximum capacity of the autoclave is 250 ml of solution. the carbon steel specimen used in this investigation has the chemical composition shown in table (1). fig.1, schematic diagram of experimntal setup reducing of corrosion rate in boiler tubes by using oxygen scavengers 24 ijcpe vol.16 no.4 (dec. 2015) -available online at: www.iasj.net the rectangular carbon steel alloy specimens of dimensions (3 x 1.5 x 0.2 cm) have been used before each experiment, one specimen was abraded in sequence under running tap water by using emery paper of grade number (80, 220, 400, 600, 1000) respectively, washed in distilled water, dried with clean tissue, immersed in acetone and dried with clean tissue, immersed in benzene and dried with clean tissue, and then dried with an air blower, then kept in desiccators over silica gel until use (astm g1, 2004). table 1, composition of carbon steel element % iron ( fe) 99.437 carbon (c) 0.156 manganes (mn) 0.29 sulphur (s) 0.007 silicon (si) 0.1 phosphorus (p) 0.01 after preparing the specimen and regulation of water ph,for each experiment the specimen weighted and recorded (w1) then hanged inside the autoclave by insulated wire to prevent any attachment with another metal in the autoclave which cause galvanic corrosion, then (250 ml) of pure water or a solution of water with known value of concentration ( 40, 60 or 80 ppm) put in the autoclave. the autoclave was closed tightly, and n2 gas was injected providing no leaking occur. after that the temperature regulator turned on and set it to the required temperature. once the temperature reached to the required value, n2 gas injected to raise the pressure inside the autoclave to the required value. from that time, the test period started. the exposure time was (2) hours for each experiment. after (2) hours, the heating cut off, the specimen was removed and cleaned by washing it with running tap water using a plastic brush, then the specimen was immersed in cleaning solution for (10) minutes with continuous stirring to remove the corrosion products then washed with tap water followed by deionized water and dried, after that the specimen was weighed and represented as (w2). the surface area of the specimen is (10.8) cm 2 . the corrosion rate was estimated in mpy (mils penetration per year) which is a unit of measurement equal to one thousandth of an inch. ( ) where: mpy: mils per year. w: weight loss in milligrams. d: density in grams per cubic centimeter. a: area in square inches. t: time in hours. result and discussion 1temperature effects the effect of temperature in the range (100,120,140,160) indicates that higher temperature increases the electrochemical reaction and hence increase corrosion rate of carbon steel, figure (2), but when adding any one of the used oxygen scavengers to water at the same temperature leads to reduce the effect of temperature on corrosion rate. it is observed that (80) ppm of any scavenger give best results and it was found that hydroquinone is more stable and more effective than the other scavengers at different temperatures, figures (3,4 &5) saad a jafar and mohammed i fathi -available online at: www.iasj.net ijcpe vol.16 no.4 (dec. 2015) 25 fig. 2, temperature and corrosion rate with pure water fig. 3, temperature and corrosion rate at (7) bar with different concentrations of hydroquinone fig. 4, temperature and corrosion rate at (7) bar with different concentrations of ascorbic acid fig. 5, temperature and corrosion rate at (7) bar with different concentrations of ethanolamine 2the effect of pressure it was observed a positive relationship between the corrosion rate and pressure (rate of corrosion tends to increase with rising pressure). it is known; however that pressure alters the thermodynamics of corrosion and increases the solubility of oxygen and the rate of solution. the reason behind this varying effect of pressure probably depends on the alteration of other corrosion limiting factors, or on the modification of their synergistic actions. figure (6) shows the effect of pressure on corrosion rate of carbon steel with distilled water with no addition and figures (7 to 9) show how the scavengers decrease the effect of ˚. fig. 6, the relation between pressure and corrosion rate with distilled water 0 50 100 150 200 250 300 350 400 100 120 140 160 c o r r o si o r a te , m p y temp. c ͦ 7 bar 10 bar 13 bar 0 50 100 150 200 100 120 140 160 c o r r o si o n r a te ,m p y temp. c ͦ no additive 40 ppm 60 ppm 80 ppm 0 20 40 60 80 100 120 140 160 180 200 100 120 140 160 c o r r o si o n r a te , m p y temp. c no additives 40 ppm 60 ppm 80 ppm 0 50 100 150 200 100 120 140 160 c o r r o si o n r a te , m p y temp, c ͦ no additive 40 ppm 60 ppm 80 ppm 0 50 100 150 200 250 300 350 400 7 10 13 c o r r o si o n r a te , m p y pressure, bar at 100 c ͦ at 120 c ͦ at 140 c ͦ at 160 c ͦ reducing of corrosion rate in boiler tubes by using oxygen scavengers 26 ijcpe vol.16 no.4 (dec. 2015) -available online at: www.iasj.net fig. 7, the relation between pressure and corrosion rate with different concentrations of hydroquinone solution at 100 fig. 8, the fig. 9, the relation between pressure and corrosion rate with solution of different concentrations 3the effect of scavenger concentration oxygen scavengers were added to demineralized water in three concentrations (40, 60 and 80) ppm at different conditions of temperature and pressure. it can be observed an inverse relationship between the corrosion rate and the concentration of scavengers (rate of corrosion decreases with increasing the concentration of scavenger in solution at constant temperature and pressure). the reason of this behavior, when increasing the concentration of reactants (scavenger) leads to the consumption of larger amount of dissolved oxygen leading to reduce the rate of corrosion. [13] figures from (10) to (18) show the relation between corrosion rate and the concentration of scavengers at constant ph (9) and different conditions of temperatures and pressures. fig. 10, the relation between concentration of hydroquinone and corrosion rate at different temperatures and (7) bar 0 50 100 150 200 7 10 13 c o r r o si o n r a te , m p y pressure, bar no additive 40 ppm 60 ppm 80 ppm 0 20 40 60 80 100 120 140 160 180 200 7 10 13 c o r r o si o n r a te , m p y pressure, bar no additive 40 ppm 60 ppm 80 ppm 0 20 40 60 80 100 120 140 160 180 200 7 10 13 c o r r o si o n r a te , m p y pressure, bar no additive 40 ppm 60 ppm 80 ppm 0 10 20 30 40 50 60 70 80 40 60 80 c o r r o si o n r a te , m p y conc. ppm at 100 c ͦ at 120 c ͦ at 140 c ͦ at 160 c ͦ saad a jafar and mohammed i fathi -available online at: www.iasj.net ijcpe vol.16 no.4 (dec. 2015) 27 fig. 11, the relation between concentration of ascorbic acid and corrosion rate at different temperatures and (7) bar fig. 12, concentration of ethanolamine and corrosion rate at different temperatures and (7) bar fig. 13, concentration of hydroquinone and corrosion rate at different temperatures and 10 bar fig. 14, concentration of ascorbic acid and corrosion rate at different temperatures and 10 bar fig. 15, concentration of ethanolamine and corrosion rate at different temperatures and 10 bar fig. 16, concentration of hydroquinone and corrosion rate at different temperatures and 13 bar 0 20 40 60 80 100 120 140 160 40 60 80 c o r r o si o n r a te ,m p y conc. ppm at 100 c ͦ at 120 c ͦ at 140 c ͦ at 160 0 10 20 30 40 50 60 70 80 90 100 40 60 80 c o r r o si o n r a te , m p y conc. ppm at 100 c ͦ at 120 c ͦ at 140 c ͦ at 160 c ͦ 0 20 40 60 80 100 120 140 160 40 60 80 c o rr o si o n r a te , m p y conc. ppm at 100 c ͦ at 120 c ͦ at 140 c ͦ at 160 c ͦ 0 50 100 150 200 250 40 60 80 c o r r o si o n r a te , m p y conc. ppm at 100 c ͦ at 120 c ͦ at 140 c ͦ at 160 c ͦ 0 50 100 150 200 250 40 60 80 c o r r o si o n r a te , m p y conc. ppm at 100 c ͦ at 120 c ͦ at 140 c ͦ at 160 c ͦ 0 20 40 60 80 100 120 40 60 80 c o r r o si o n r a te , m p y conc. ppm at 100 c ͦ at 120 c ͦ at 140 c ͦ at 160 c ͦ reducing of corrosion rate in boiler tubes by using oxygen scavengers 28 ijcpe vol.16 no.4 (dec. 2015) -available online at: www.iasj.net fig. 17, concentration of ascorbic acid and corrosion rate at different temperatures and 13 bar fig. 18, concentration of ethanolamine and corrosion rate at different temperatures and 13 bar measurement of dissolved oxygen ( o) . ( . ) ( ) . method was used in determining the concentration of dissolved oxygen after adding each scavenger. the concentration of dissolved oxygen was measured after (24) hours of preparation solutions of (40,60 and80) ppm of each scavenger to ensure completing the reaction between scavengers and oxygen, the (do) values after adding each concentration of scavengers is shown in table (2). determining the speed of reaction between dissolved oxygen and scavengers winkler method and digital (do) meter were used to find the concentration of dissolved oxygen in solution of water and (80) ppm of eac ( ) ( ) . f (19) shows the rate of oxygen consumed by plotting the concentration of (do) with time. it has been observed that hydroquinone reacts rapidly with oxygen at (25) while the other scavengers (ascorbic acid and ethanolamine) react slowly with oxygen at the same temperature. table 2, the remained do after adding different concentration of scavengers scavenger dissolved oxygen, ppm 0 ppm 40 ppm 60 ppm 80 ppm hydroquinone 8.2 3.8 2.2 0.8 ascorbic acid 8.2 4.7 2.6 1.4 ethanolamine 8.2 5.3 3.7 1.9 this means that hydroquinone reacts with oxygen quickly, even at low temperatures, while ascorbic acid and ethanolamine need high temperatures to increase the speed of reaction and may need to add oxidation catalysts to increase the speed of reaction with oxygen and their efficiency. [13] this analysis is important for the evaluation of the used scavengers in this research. it gives an indication about the reaction speed, residence time in the system which effect on ability of the scavenger to remove oxygen as well as the preferred choice of the places in boiler system where the injected scavenger gives the best results. 0 50 100 150 200 250 300 40 60 80 c o r r o si o n r a te , m p y conc. ppm at 100 c ͦ at 120 c ͦ at 140 c ͦ at 160 c ͦ 0 50 100 150 200 250 300 350 40 60 80 c o r r o si o n r a te , m p y conc. ppm at 100 c ͦ at 120 c ͦ at 140 c ͦ at 160 c ͦ saad a jafar and mohammed i fathi -available online at: www.iasj.net ijcpe vol.16 no.4 (dec. 2015) 29 fig. 19, reaction rates of oxygen h conclusion 1the corrosion rate of carbon steel in water at constant pressure and (ph) increases with temperature. 2the corrosion rate of carbon steel decreases when adding oxygen scavengers. 3oxygen scavengers react with dissolved oxygen in water and they work on the consumption of oxygen. 4oxygen scavengers differ among themselves in susceptibility removal of oxygen, the reason for this difference is mechanisms of the chemical reaction of each scavenger at the same conditions. 5the best results were obtained when adding (80) ppm of each scavenger because of consumption the most of do. 6hydroquinone is the best of the others in oxygen scavenging at different conditions. 7hydroquinone reacts quickly and spontaneously with dissolved oxygen in water at low temperatures while ascorbic acid and monoethanolamine react slowly with dissolved oxygen at the same conditions. references 1pincus, l. i., (1962),“practical boiler water treatment”, mcgrawhill, new york. 2james w. mccoy, (1981), “the chemical treatment of boiler water”, chemical publishing co., new york. 3leonard hill, (1966), “corrosion and its prevention in water”, london. 4frayne, colin, (2002), “boiler water treatment principles and practice”, chemical publishing co. new york. 5james w. mccoy, (1981),“the chemical treatment of boiler water”, chemical publishing co., new york. 6ciuba j. stanley, (1981), “hydroquinone as an oxygen scavenger in aqueous medium”, u.s. patent no.(4282111). 7d.a. jones, (1996), “corrosion principles and prevention of corrosion”, 2nd ed., prentice hall. 8kerst herman, (1981), “method for de oxygenation of water”, u.s. patent no.(4278635). 9j.g baker, (1983), “anti-corrosion, a new approach to controlling corrosion throughout the entire steam boiler system”, february, p. 5. 10denny a. jones, (1992), “principles and prevention of corrosion”, maxwell macmillan. 11joan estil. les, manuel soria, (2005), “reducing corrosion and potential boiler failure with superior iron transport technology”, gew&pt. 12nathan, c. c., (1973), “corrosion inhibitors”, national association of corrosion engineers, houston. 13f . m ( ) “using of oxygen scavengers to reduce the corrosion rate of carbon steel u b ” m ikrit university, engineering college. iraqi journal of chemical and petroleum engineering vol.16 no.2 (june 2015) 1929 issn: 1997-4884 preparation and characterization of nay zeolite for biodiesel production ammar s. abbas and rowaida n. abbas chemical engineering department, college of engineering – university of baghdad abstract iraqi kaolin was used for the preparation and characterization of nay zeolite for biodiesel production via esterification reaction. oleic acid was used usually as a typical simulated feedstock of high acid number for the esterification reaction. the chemical composition for the prepared nay zeolite is as following: (ca2.6na1.k0.1)(al6.3si17.7)o48.16h2o, the silica to alumina ratio in the prepared catalyst was found equal to 2.6 and na2o content was 12.26 wt. %, with relative crystallinity equal to 147.4 % obtained by the x-ray diffraction. the surface area result shows that the prepared catalyst has 330 m 2 /g. while, the measured pore volume by nitrogen adsorption was equal to 0.35 cm 3 / g. sem images show notable differences between the kaolin crystal and prepared nay crystal. the effect of nay zeolite, as a loaded catalyst in the esterification of oleic acid reaction did not show any significant change of oleic acid conversion for catalyst load more than 5 wt. %. the reused nay zeolite is loses 31 % of its activity because of that the pores are filled with water and other organic molecules and that may cause poisoning the catalyst. key words: nay, zeolite, esterification, characterization, catalyst. introduction the energy consumption in the global has been increasing steadily for a variety of reasons, which include enhancements in quality of life, population increase, industrialization, rapid economic growth of developing countries, increased transportation of people, goods, etc. [1]. in the recent years, there has been increased focus on global warming and the depletion of resources caused by the heavy consumption of fossil resources, have become major global issues. the use of biofuel such as biodiesel can help firmness this problem as biofuels are renewable sources of energy [2]. biodiesel has gained international attention as a source of alternative fuel due to characteristics like high degradability, no toxicity, low emission of carbon monoxide, particulate matter and unburned hydrocarbons [3]. biodiesel is a mixture of alkyl esters, contains 10 to 15% oxygen by weight and sulfur-free, it can be used in conventional compression ignitions engines, which need almost no modification. as well, biodiesel can used as heating oil and as fuel [4]. iraqi journal of chemical and petroleum engineering university of baghdad college of engineering preparation and characterization of nay zeolite for biodiesel production 20 ijcpe vol.16 no.2 (june 2015) -available online at: www.iasj.net catalysts investigated for the transesterification are either acids or bases, both homogeneous and heterogeneous, or they are enzymes [5]. conventionally, commercial biodiesel produced by using traditional liquid base catalysts [6]. however, there is a considerable incentive for the substitution of liquid bases by solid bases for the following reasons: (a) energy intensive product/catalyst separation, (b) corrosiveness and (c) the costs associated with the disposal of spent or neutralized caustics [7]. in other words, the use of heterogeneous catalysts allows a more environmentally friendly process to be used for biodiesel production. in addition, the use of heterogeneous catalysts could enable the design of an efficient, continuous process and improve the economics of biodiesel production [8]. furthermore, the use of heterogeneous catalysts do not produce soaps through free fatty acid neutralization [9], which simplifies the post-treatment (i.e. separation and purification) processes. because of these advantages, research on the transesterification or esterification reaction using heterogeneous catalysts for biodiesel production has increased over the past decade [10]. heterogeneous catalysts now being tried extensively for biodiesel synthesis. these catalysts are poised to play an important role in future for biodiesel production at industrial level[11]. the use of homogeneous catalysts leads to soap production. besides, in the homogeneous process the catalyst consumed, thus, reducing the catalytic efficiency. this causes an increase in viscosity and the formation of gels. in addition, the method for the removal of the catalyst after reaction is technically difficult and a large amount of wastewater produced in order to separate and clean the products, which increases the overall cost of the process [12]. during homogeneous catalytic transesterification the glycerol produced is of low quality and requires lengthy process and distillation for purification [13]. all these processing increases the cost of the end-products: biodiesel and glycerin. moreover, the homogeneous base catalyzed transesterification process encountered problems to handle multiple feedstock. on the other hand, heterogeneous catalytic transesterification process overcomes these problems because methanol or ethanol does not mix with solid heterogeneous catalyst. after the transesterification reaction, it is relatively easy to separate the catalyst from biodiesel and glycerol [14]. the heterogeneous catalytic transesterification is included under green technology due to the following attributes [15]: (1) the catalyst can be recycled (reused), (2) there is no, or very less, amount of wastewater produced during the process and (3) separation of biodiesel from glycerol is much easier. the main advantages of the process described as the production of highquality glycerol and no need for disposal of salts resulting from the catalyst. however, the overall economic advantages have to be proved in long-term running. additional benefit with solid based catalyst is the slighter consumption of catalyst. as per studies, for production of 8000 tons of biodiesel, 88 tons of sodium hydroxide may be required [16], while only 5.7 tons of solid supported mgo is sufficient for production of 100,000 tons of biodiesel [17]. heterogeneous catalyst offers easier production process, improve product quality, and reduce corrosion and toxicity problems. furthermore, it can ammar s. abbas and rowaida n. abbas -available online at: www.iasj.net ijcpe vol.16 no.2 (june 2015) 21 used for low quality feedstock, which contains high ffa [18]. low-cost feedstock needs pretreatment (esterification) to remove ffas before base catalyzed transesterification reaction. the esterification path is relatively simple reversible reaction as shown in equation 1. … (1) in the reaction (eq. 1), ffa is converting to fame. when homogenous acid (e.g., sulfonate acid, phosphorus acid and hydrochloric acid) used, esterification reaction is a process that ffa supply hydroxide and methanol supply proton without intermediate process. different to homogeneous catalysis, heterogeneous catalytic is a process known to follow a carbonium ion mechanism. the mechanism of solid acid-catalyzed esterification consists of following steps as shown in figure 1. firstly, solid catalysts provided protons, and carbonyl carbon was protonated. next, nucleophilic attack of ch3oh on the carbonium ion formed a tetrahedral intermediate. finally, fame produced after proton migrated and the intermediate broke down, and proton was reformed [19]. the esterification reaction path is slightly different in various acidic species types. the whole reaction process is through proton-exchange. tesser et al. [20] proposed a kinetic model based on the following hypotheses: (1) major part of the active sites are occupied by methanol in a protonated form, and the rest part are also occupied; (2) fatty acid, water and methyl ester reach proton-exchange equilibrium with the protonated methanol; (3) inside the resin particles, an eley-rideal mechanism occurs between protonated fatty acid and the methanol. deviate from the mechanism shown in figure 1, steps of protonation of carbonyl carbon, nucleophilic attack, proton migration and breakdown of intermediate are undergoing in a proton exchange way. fig. 1, solid acid-catalyzed reaction mechanism of esterification [20] preparation and characterization of nay zeolite for biodiesel production 22 ijcpe vol.16 no.2 (june 2015) -available online at: www.iasj.net the aim of this research is the preparation and characterization of nay zeolite from iraqi kaolin suitable for esterification of oleic acid. the characterization of the prepared zeolite catalyst includes composition, x-ray diffraction (xrd), surface area and pore volume and scanning electron microscopic (sem). finally, the prepared nay will tested as a catalyst for the oleic acid esterification at selected conditions to study the load effect of catalyst and its age. experimental work catalyst preparation iraqi kaolin (chemical composition listed in table 1) sieved to a particle size less than 75µm. table 1, chemical analysis of iraqi kaolin component wt. % sio2 49.64 fe2o3 1.72 al2o3 34.05 cao 1.10 na2o 0.46 l.o.i. 12.28 the sieved kaolin was mixed with 40 % sodium hydroxide solution using (kaolin/naoh = 1/1.5) and fused at 850˚c for 3 hours. 50 g of fused kaolin and 63 g of sodium silicate were pressed in 500 ml of de-ionized water under constant stirring at 50˚c for 1 hour by electric magnetic stirrer, and then the slurry with ph 13.3 was placed in 1000 ml glass jar and subjected to ageing at 50 ᵒc for 24 hours in a programmable electrical furnace. the product slurry crystallized at 100 ᵒc for 48 h in a programmatic electrical furnace. the yield crystalline repeatedly washed with water until ph arriving to 11.7, and then the crystalline mass dried at 100 ᵒc for 16 hours by using programmatic electrical furnace. catalyst characterization x-ray diffraction and x-ray florescence x-ray diffraction and x-ray florescence analyses achieved in department of geological science – college of sciences in university of baghdad. chemical analysis the percent of silica and alumina in prepared zeolite catalyst and the chemical analysis measured in state company of geological and mineral – ministry of industry and minerals. surface area and pore volume determination of prepared catalyst surface area and pore volume obtained at oil development and research center-ministry of oil, using bet method by thermo-finnegan type apparatus. sem (scan electron microscopy) scan electron microscopy achieved in ministry of science and technology. esterification of oleic acid the desired amount of catalyst (nay zeolite) for every experiment was calcinated at 300 °c up to 3 hours to eliminate any possible amount of water. the reactor (kept in water bath) was loaded with 30 ml of oleic acid (with specific gravity of 0.895) and mixed with the same amount of iraqi commercial ethanol (88 wt. %), start agitation with 300 rpm to have a good mixing of the compounds and eliminate possible mass transfer problems. the reaction mixture preheated to the reaction temperature and then addition ammar s. abbas and rowaida n. abbas -available online at: www.iasj.net ijcpe vol.16 no.2 (june 2015) 23 a certain amount of nay zeolite to ensure the desired catalyst load. after one hour the mixture reaction was taken and centrifuged for 10 min to improve the separation of the phases (catalyst, and other phases). then, two to three drops of phenolphthalein was added to the organic phase and titrated with 0.2 molarity of naoh in order to obtain oleic acid conversion, the equations for calculating conversion from each catalyst concentration (2, 5 and 10 wt. % nay) are obtained as: ... (2) the acid number of oleic acid obtained according to astm d-664. the reactor setup details and the selected best conditions for the reaction for the esterification of oleic acid over nay zeolite reported in previous work [21]. results and discussion characterization of prepared catalyst x-ray diffraction and x-ray florescence the purity of solid crystal measured by comparing the x-ray diffractgram pattern of sample with x-ray pattern of standard that can be obtained from international zeolite association [22]. x-ray diffraction pattern was determined for prepared nay zeolite as shown in fig. 2. fig.2, x-ray diffraction spectrum for the prepared nay zeolite a relative crystallinity of nay zeolite was obtained by comparing the summation of integrated peak intensities of sample and reference, the values of the peak intensities were used for determination the area under the peaks of the strongest intensities [23], and the values of the area under the peaks were used for estimation of relative crystallinities % by equation 3 and it was equal to 147.4 % for the prepared nay zeolite. … (3) where: sx= sum of integral peak intensities for sample nay sr= sum of integral peak intensities for the reference nay the comparison between lattice spacing of prepared nay zeolite with standard synthesis faujasite is shown in table 2. preparation and characterization of nay zeolite for biodiesel production 24 ijcpe vol.16 no.2 (june 2015) -available online at: www.iasj.net table 2, comparison of lattice spacing, between prepared catalyst and standard synthesis faujasite-na prepared nay standard synthesis faujasite na angle (2-theta) deg. d, spacing (å ) angle (2-theta) deg. d, spacing (å ) 12.47 7.09 12.59 7.02 18.24 4.85 18.65 4.36 21.64 4.1 21.80 4.07 25.91 3.4 26.64 3.30 28.07 3.17 28.27 3.15 32.7 2.7 32.04 2.7 33.31 2.5 33.56 2.66 35.74 2.5 35.90 2.53 37.0 2.4 37.72 2.4 40.4 2.23 40.3 2.23 44.11 2.05 44.36 2.04 the comparison between the lattice spacing shows that the prepared nay zeolite is approximately comparable with the standard. as shown in the result of xrd for the prepared nay zeolite (fig. 2), the ions such as calcium, sodium, potassium, aluminum, silicon, oxygen, may be exist in addition to water. the increasing in silica content, sodium content, potassium content increasing the acidity of the prepared catalyst. while increasing in calcium content decreasing the acidity of the catalyst. the result of xrd shows that the prepared catalyst has an amount of moisture; therefore, drying needed before using the catalyst in the esterification reaction. the chemical composition for the prepared catalyst is (ca2.6na1.k0.1)(al6.3si17.7)o48.16h2o. the positive ions such as na + , ca + and k + are more rarely elements belonging to other columns of the periodic classification such as la3 + . groups of atoms such as ammonium cation nh4 + are also common structures which balance the negative charge of the zeolite framework. however, the nature of the cation determines the acidic catalytic power of the zeolite. the higher brønsted acidity of a zeolite is obtained when the extra framework cation is hydrogen h + [24]. chemical analysis the silica to alumina ratio in the prepared catalyst was found equal to 2.6, this result is in a good agreement with davis and davis [25] who reported that the ratio of silica to alumina in nay is about 2.4. the silicon to aluminum ratio is one of the parameters that govern the zeolite’s reactivity. based on the general formula of the zeolite the number of charged entities within the structure is closely related to the amount of aluminum atoms. the more alo4 groups in the zeolite, the more negative charge that needs to be balanced and consequently, the more positive counter-ions. on top of assuring the electro-neutrality of the structure, those positive ions play an important role in the reactivity of the zeolite due to their location outside of the al-o-si framework. as explained above, their number is closely related to the number of alo4 units and consequently to the si/al ratio. if the silicon-to-aluminum ratio has a strong influence on the reactivity (and catalytic power) of the zeolite, it also has a huge impact of its affinity towards water. indeed, the higher si/al ratio, the more hydrophobic the zeolite and vice-versa [26]. decreasing the si/al ratio increases the affinity of the zeolite towards water and in the case of a reaction between organic species catalyzed by the acid properties of the zeolite, water molecules are more likely to adsorb on the surface of the zeolite causing a deactivation of the catalyst and thus a ammar s. abbas and rowaida n. abbas -available online at: www.iasj.net ijcpe vol.16 no.2 (june 2015) 25 drop in conversion. on the other side, increasing the si/al ratio decreases the affinity of water towards the catalyst which is more available to interact with organic species and efficiently play the role of acid catalyst for the organic reaction [24]. na2o content of prepared nay zeolite was analyzed and it was 12.26 wt. %. this result is in agreement with the result published mohammed and dahyool [27]. they recorded that nay zeolite contains approximately 12.5 wt% na2o. it is important for the fresh zeolite to contain very low amount of sodium, sodium decrease the hydrothermal stability of zeolite and it is also react with the zeolite acid sites and reduces catalyst activity. sodium is commonly reported as the weight percentage of sodium or soda (na2o) on catalyst [28]. surface area and pore volume the surface area of prepared catalyst was measured by nitrogen physical adsorption at liquid nitrogen temperature using the bet (brunauer, emmett, and teller) method, and equal to 330 m 2 /g. a high surface area is obvious due to the micro porosity of prepared powdered zeolite [29]. an increase in surface area generally increases the catalyst activity. furthermore, high surface area usually has a high percentage of small pores, which are hydrothermally less stable than large pores [30]. pore volume is a measure the void space in the catalyst. it is measured by nitrogen adsorption and expressed in cm 3 /g. for the prepared catalyst, it was equal to 0.35 cm 3 / g. sem (scan electron microscopy) sem characterization techniques were performed on the kaolin and the prepared catalyst. sem image of kaolin and nay can be seen in figure 3 (a and b, respectively). it is clear the notable differences between the kaolin crystal and prepared nay crystal. since that, the sem picture is like the fingerprint of the prepared crystal, it is very convenient to compare the prepared nay zeolite crystal with prepared nay zeolite by zaidi and rohani [31]. fig. 3, sem for iraqi kaolin, prepared nay zeolite and prepared zeolite preparation and characterization of nay zeolite for biodiesel production 26 ijcpe vol.16 no.2 (june 2015) -available online at: www.iasj.net effect of catalyst load on the oleic acid conversion the catalyst load effect on the oleic acid conversion at selected operating conditions shown in figure 4, which demonstrated the relationships between the oleic acid conversion and time at various catalyst load. generally, the oleic acid conversion increased with increasing the catalyst load. the reaction rate of esterification is directly proportional to the amount of a catalyst, due to the increase of active site numbers, so the catalyst used to enhance the reaction rate and conversion. at catalyst weight present more than 5 wt. % the effect of catalyst load did not show any remarkable effect on oleic acid conversion, that may be due to increasing the surface area of zeolite catalyst that causes more accumulation of water in the pores as a result of the hydrophilic action of the zeolite [32]. this accumulation of water increasing backward reaction. time (min) 0 20 40 60 80 100 120 140 160 o le ic a c id c o n v e r s io n 0.0 0.2 0.4 0.6 0.8 1.0 cat=2% wt cat=5% wt cat=10% wt fig. 4, effect of catalyst load (nay) on oleic acid conversion by esterification reaction, at the temperature 70 ° c marchetti and errazu [33] reached to 26% conversion of oleic acid by using nay zeolite with a molar ratio 6/1 and the amount of catalyst 2.6 wt. %, while the conversion in our work reached to 66 % at 2 wt. % of nay and 70 °c, and this may be casus by the transition metals (such as fe +2 ), that found in iraqi kaolin. catalyst reuse the solid catalyst needs regenerated when they used for a period in order to have good performance. stopping the reaction and regeneration the catalyst is an expensive non-conventional operation [34]. the used nay catalyst (for 3 hours) reused after drying it at 100 °c for 24 hours (without regeneration). the conversion decreased from 0.81 (for fresh catalyst and 1 hour reaction time) to 0.56 (for reused catalyst), as shown in figure 5. the conversion decreases about 0.25 (about 31 %) due to poisoning of the catalyst by the trapped water and other reactant and product molecules. time (min) 0 20 40 60 80 100 120 140 160 o le ic a c id c o n v e r s io n 0.0 0.2 0.4 0.6 0.8 1.0 normal use reuse cat fig. 5, effect of the reaction time on oleic acid conversion by the esterification reaction using fresh and reuse nay at the temperature 70 ° c marchetti et.al [35] using resins as a catalyst for esterification reaction. temperature was set at 45 °c, the molar ratio of alcohol to oil was 6/1, and the speed of agitation was 200 rpm. the percentage of catalyst ammar s. abbas and rowaida n. abbas -available online at: www.iasj.net ijcpe vol.16 no.2 (june 2015) 27 changed irrelevantly due to the some loss when the reactor washed and refilled; however, this variation has no effect on the equilibrium conversion allowing for the comparison of the results obtained. the conversion decreases from 0.8 for the fresh catalyst to 0.2 for first, second and third reuses. conclusions according to the results obtained from this study, the following conclusions obtained: 1from the results of x-ray diffraction pattern, silica to alumina mole ratio (2.6), sodium content (12.26 wt. %), surface area (330 m 2 /g) and pore volume (0.35 cm 3 /g) for the prepared nay zeolite, and by the comparison sem with the standard nay zeolite, it is possible to say that the prepared catalyst in this work is matching the standard. 2the conversion of oleic acid increasing with the amount of nay zeolite catalyst from 2 to 10 wt. %. 3the best nay catalyst load weight ratio is 5% for esterification reaction of oleic acid. 4the fresh nay zeolite catalyst gives conversion as high as 81 % during only one hour reaction, 5the reused nay zeolite catalyst loss about 31 % of its activity for esterification reaction of oleic acid. references 1lee s., speight j.g., loyalka s.k., “a hand book of alternative fuel technologies” , by taylor & francis group, llc, 2007. 2hameed, b.h., lai, l.f., chin, l.h., “production of biodiesel from palm oil (elaeisuineensis) using heterogeneous catalyst: an optimized process”. fuel process.technol, vol. 90, pp. 606– 610, 2009. 3al zuhair s., “production of biodiesel: possibilities and challenges.” biofuels bioproduct and biorefining, vol.1, pp. 57–66, 2007. 4wardle d.a., “global sale of green air travel supported using biodiesel.”, renewable and sustainable energy review, vol. 7, pp. 1–64, 2003. 5agarwal, a.k., bajaj, t.p., “process optimisation of base catalysed transesterification of karanja oil for biodiesel production.” int. j. oil gas coal technol, vol. 2, pp. 297–310, 2009. 6meher, l.c., sagar, d.v., naik, s.n., “technical aspects of biodiesel production by transesterification: a review.” renew. sustain. energy rev., vol. 10, pp. 248–268, 2006. 7zhang, y., dube, m.a., mclean, d.d., kates, m., “biodiesel production from waste cooking oil: 1. process design and technological assessment.” bioresour. technol., vol.89, pp.1– 16, 2003. 8mcneff, c.v., mcneff, l.c., yan, b., nowlan, d.t., rasmussen, m., gyberg, a.e., krohn, b.j., fedie, r.l., hoye, t.r., “a continuous catalytic system for biodiesel production.” appl. catal., vol.343, pp.39–48, 2008. 9vicente, g., martinez, m., aracil, j., “integrated biodiesel production: a comparison of different homogeneous catalysts systems”, bioresour. technol., vol. 92, pp.297–305, 2004. 10islam a., taufig-yap y.h., chu c. and chan e., “ studies on design of heterogeneous catalysts for biodiesel production”, process safety and environmental protection, vol.91, pp. 131-144, 2013. preparation and characterization of nay zeolite for biodiesel production 28 ijcpe vol.16 no.2 (june 2015) -available online at: www.iasj.net 11sharma yc, singh b, korstad j. , “ latest developments on application of heterogenous basic catalysts for an efficient and ecofriendly synthesis of biodiesel: a review.”, fuel , vol.90, pp.1309–24, 2011. 12taguchi f., mizukami n., hasegawa k. and saito-taki t., “microbial conversion of arabinose and xylose to hydrogen by a newly isolated clostridium” sp. no.2, can. j. microbiol., vol.40, pp.228–233, 1994. 13canakci m, van gerpan j. “biodiesel production from oils and fats with high free fatty acids.” trans asae, vol.44, pp.1429–36, 2011. 14singh chouhan a. p., sarma a. k., “modren heterogeneous catalysts for biodiesel production: a comprehensive review”, renewable and sustainable energy review, vol.15, pp.4378–4399, 2011. 15juan jc, kartika da, wu ty, hin tyy., “biodiesel production from jatropha oil by catalytic and noncatalytic approaches: an overview.” bioresource technology, vol.102, pp.452–60, 2011. 16mbaraka, i.k., shanks, b.h., “conversion of oils and fats using advanced mesoporous heterogeneous catalysts.” j. am. oil chem. soc., vol. 83, pp.79–91, 2006. 17dossin, t.f., reyniers, m.f., berger, r.j., marin, g.b., “simulation of heterogeneously mgo-catalyzed transesterification for fine-chemical and biodiesel industrial production.” appl. catal. b: gen., vol.67, pp.136–148, 2006. 18mat, r., samsudin r.a., mohamed m., johari a., “solid catalysts and their application in biodiesel production”, vol.7 (2), 142 – 149, 2012. 19guo f. and fang z., “biodiesel production with solid catalysts”, chinese academy of sciences, biomass group, xishuangbanna tropical botanical garden,china , 2011. 20tesser, r., serio, m.d., carotenuto, g., santacesaria, e., “absorption of water/methanol binary system on ion-exchange resins.” canadian journal of chemical engineering, vol.88, no.6, pp.1044-1053, 2010. 21abbas, a.s. and abbas, r. n., “kinetic study and simulation of oleic acid esterification over prepared nay zeolite catalyst”, iraqi journal of chemical and petroleum engineering, vol.14 no.4, pp. 35-43, 2013. 22west, a.r., "basic solid state chemistry", new york: johnwiley and sons inc, 1988. 23treacy, m. m., and higgins, j. b., "collection of simulated xrd powder patterns for zeolite", published on behalf of the structure commision of the international zeolite association 4 th edition, elsevier amsterdam, 2001. 24gaetan, l., “comparison of different types of zeolits used as solid acid catalysts in the transesterification reaction of jatropha type oil for biodiesel production”, a thesis submitted to the faculty of the worcester polytechnic institute, 2013. 25davis m.e. and davis r.j., “fundamentals of chemical reaction engineering”, mcgraw hill, boston, pp. 166-170, 2003. 26okuhara t., "water-tolerant solid acid catalysts," chemical reviews, vol. 102, pp. 3641-3665, 2002. 27mohammed a.a. and dahyool n.a., “the effect of promoters on ammar s. abbas and rowaida n. abbas -available online at: www.iasj.net ijcpe vol.16 no.2 (june 2015) 29 the activity of prepared zeolite catalyst in fcc process”, iraqi journal of chemical and petroleum engineering, vol.14 no.2, pp.1-6, 2013. 28nuanklai s., "effects of particle size and hydrothermal treatment of y-zeolite on catalytic cracking of n-octane", m.sc. , university of chulalongkorn, 2004. 29scott m. auerbach, kathleen a. carrado, and prabir k. dutta "handbook of zeolite science and technology", marceld ekkeirnc inc, 2003. 30scherzer j., "designing fcc catalysts with high-silica y zeolites", applied catalysis, 75, 1991. 31zaidi s.s.a., and s. rohani, “synthesis and characterization of nay zeolite”, the 15th international symposium on industrial crystallization (isic), sorrento, italy, 15-18 september 2002. 32zubir m.i., chin s.y., "kinetic of modified zirconiz-catalyzed heterogeneous esterification reaction for biodiesel production", journal of applied sciences, vol.10 (21), pp.25842589, 2010. 33marchetti j.m., and errazu a.f., “comparison of different heterogeneous catalysts and different alcohols for the esterification reaction of oleic acid”, fuel, vol.87, pp.3477-3480, 2008. 34marchetti j. m., miguel v. u., and errazu a. f., "possible methods for biodiesel production," renewable and sustainable energy reviews, vol. 11, pp. 1300-1311, 2007. 35marchetti j.m., miguel a.u., errazu a.f., “heterogeneous esterification of oil with high amount of free fatty acids”, fuel, vol.86, pp.906-910, 2007. iraqi journal of chemical and petroleum engineering vol.14 no.4 (december 2013) 1118 issn: 1997-4884 a study of water flux through forward osmosis membrane using brine\fresh water system adel a. al-hemiri and marwah m. kamil environmental engineering department-college of engineering-university of baghdad-iraq abstract the present work aims to improve the flux of forward osmosis with the use of thin film composite membrane by reducing the effect of polarization on draw solution (brine solution) side.this study was conducted in two parts. the first is under the effect of polarization in which the flux and the water permeability coefficient (a) were calculated. in the second part of the study the experiments were repeated using a circulating pump at various speeds to make turbulence and reduce the effect of polarization on the brine solution side. a model capable of predicting water permeability coefficient has been derived, and this is given by the following equations: z = + ( ) [exp. [ ( ) . t] -1] key word: osmosis, forward osmosis, permeable membrane. introduction membranes have gained an important place in chemical technology and are used in a broad range of applications. the key property that is exploited is the ability of a membrane to control the permeation rate of a chemical species through the membrane. in controlled drug delivery, the goal is to moderate the permeation rate of a drug from a reservoir to the body. in separation applications, the goal is to allow one component of a mixture to permeate the membrane freely, while hindering permeation of other components. systematic studies of membrane phenomena can be traced to the eighteenth century philosopher scientists. for example, abb´e nolet coined the word ‘osmosis’ to describe permeation of water through a diaphragm in 1748. through the nineteenth and early twentieth centuries, membranes had no industrial or commercial uses, but were used as laboratory tools to develop physical/chemical theories. for example, the measurements of solution osmotic pressure made with membranes by traube and pfeffer were used by van’t hoff in 1887 to develop his limit law, which explains the behavior of ideal dilute solutions; this work led directly to the van’t hoff equation. at about the same time, the concept of a perfectly selective semipermeable membrane was used by maxwell and others in developing the kinetic theory of gases [1]. following the progress in membrane science in iraqi journal of chemical and petroleum engineering university of baghdad college of engineering a study of water flux through forward osmosis membrane using brine\fresh water system 12 ijcpe vol.14 no.4 (december 2013) -available online at: www.iasj.net the last few decades, especially for reverse osmosis applications, the interests in engineered applications of osmosis has been spurred. osmosis, or as it is currently referred to as forward osmosis, has new applications in separation process for wastewater treatment, food processing, and seawater/brackish water desalination. other unique areas of forward osmosis research include pressureretarded osmosis for generation of electricity from saline and fresh water and implantable osmotic pumps for controlled drug release [2].forward (or direct) osmosis (fo) is a process that may be able to desalinate saline water sources at a notably reduced cost. in forward osmosis, like ro, water transports across a semi-permeable membrane that is impermeable to salt. however, instead of using hydraulic pressure to create the driving force for water transport through the membrane, the fo process utilizes an osmotic pressure gradient. a “draw” solution having a significantly higher osmotic pressure than the saline feed water flows along the permeate side of the membrane, and water naturally transports across the membrane by osmosis. osmotic driving forces in fo can be significantly greater than hydraulic driving forces in ro, potentially leading to higher water flux rates and recoveries. the lack of hydraulic pressure may make the process less expensive than ro, while the minimization of brine discharge reduces the environmental impact of the desalination process (jeffrey et al. [2] and gordon et al. [3]. however, a major limiting factor of fo system performance is a permeate flux decline due to concentration polarization. the present work aims to reduce the effect of polarization on brine solution side at different concentration to improve the water flux, finding the permeability coefficient for each concentration and compare these results with a mathematical model, derived in this study. experimental work materials 1. natural coarse salt (nacl), purified in the laboratory to ensure it does not contain any impurities. 2. distilled water with ph of 7 and tds 0.001. equipment 1. buchner flask with its funnel. 2. ten beakers with 1000 ml capacity. 3. filter paper with 15 cm diameter. 4. vacuum pump made by banant company. 5. mixer to dissolve coarse salt in 1 liter of distilled water. 6. magnetic stirrer for saturation concentration preparation at constant temperature (30ᵒc). 7. a digital balance with 2 decimal points was used to weigh the required quantities of materials used for preparing the samples. preparation of the draw solution (brine solution) 1. weighing the coarse salt (nacl) to give a certain concentrations and dissolving in one liter of distilled water using a mixer. 2. purification of the solution using filter paper, buchner flask with its funnel and vacuum pump and then introducing the prepared solution into the system that running the experiment. the forward osmosis system 1. the experiment rig is as shown in fig.(1), consists of a small bore leg (diameter: 0.025m; length: 1m) containing the pure water and a larger bore leg (diameter: 0.15m; length: 0.6m) containing the brine draw solution. adel a. al-hemiri and marwah m. kamil -available online at: www.iasj.net ijcpe vol.14 no.4 (december 2013) 13 2. the membrane is placed midway on the pipe connecting the two legs alongside a valve. 3. the glassware, valves and connections were all qvf supplied by corning limited. 4. for circulating the draw solution a dosing pump supplied by watsonmarlow pump limited was used. the reason for circulation is to increase turbulence and remove the concentrated solution in the neibourhood of the membrane in order to reduce polarization. fig. 1, schematic diagram of forward osmosis system the membrane used in the system is thin film composite (tfc), specifically designed for forward osmosis processes without the thick woven fabric support, is provided by koch membrane. experimental procedure 1. 10 liter of draw solution with various concentration of nacl (35, 98, 161, 224, 287, 350 gm/l) was prepared. 2. with the valve on the connecting pipe closed, the draw solution and distilled (fresh) water were placed in their respective container legs to the same level. 3. when opening the connecting valve, fresh water starts to permeate through the membrane and its level drops. the rise in the level on draw solution side is negligible since the cross section of the large leg is 36 times that of the small one, i.e., there is, hardly, any hydraulic back pressure. 4. the level in the small leg and the concentration of the draw solution are recorded every hour for duration of 5 hours. the above procedure is repeated using circulation pump flow of 4, 8, and 12 ml/sec. mathematical model the equipment is as shown in the diagram consists of a small bore leg containing pure water and a large bore leg containing brine solution. the membrane (m) is placed midway as shown. a and a are the cross sectional area of the large and small legs respectively. being the initial liquid level and z and z are the final levels after time t of the pure water and brine solution respectively. water material balance on large leg in = out + accumulation q= 0 + . ( . ) …(1) the permeate flow across the membrane, q, is also given by: q= a ( . ) [π 9.8 (z –z)] …(2) a study of water flux through forward osmosis membrane using brine\fresh water system 14 ijcpe vol.14 no.4 (december 2013) -available online at: www.iasj.net where π is the osmotic pressure, m is the molecular weight, a is the permeability coefficient and 9.8 is the conversion of meters of water to kpa from equations (3) and (4): [ ( )] …(3) water into large leg = water out of small leg (z ) . . = . ( z) ̇ = ( ) . z …(4) differentiate wrt t: = . …(5) substituting equations (6) and (7) in equation (5): [ – 9.8 ( ) +9.8 ( ) z] …(6) ( ) ∫ ( ) [ – ( ) ( ) ] = ∫ …(7) ( ) ln[ [ – ( ) ( ) ] [ – ( ) ( ) ] ] = …(8) ln [ [ – ( ) ( ) ] [ ] ] = ( ) …(9) ( ) + 9.8 ( ) z = exp. [ ( ) ] …(10) ̇ z = + ( ) [exp. [ ( ) . t] -1] …(11) vant hoff equation for nacl: = c r t …(12) substituting for in equation (11): ̇ z = + ( ) [exp. [ ( ) . t] -1] …(13) results and discussion effect of velocity on water permeability figures (2) to (7) show the comparison between effect of brine concentration on water permeability and the influence of the pump velocities 12, 8, 4 ml/sec. these have been examined on the measured height of fresh water per hour for brine solution concentrations as shown in figures. it must be mentioned that the above results are to be expected when considering vant hoff model and the model derived in this study. fig. 2, height of fresh water versus time for concentration 35 gm/l, at 2 ᵒ c fig. 3, height of fresh water versus time for concentration 98 gm/l, at 2 ᵒ c adel a. al-hemiri and marwah m. kamil -available online at: www.iasj.net ijcpe vol.14 no.4 (december 2013) 15 fig. 4, height of fresh water versus time for concentration 161 gm/l, at 2 ᵒ c fig. 5, height of fresh water versus time for concentration 224 gm/l, at 2 ᵒ c fig. 6, height of fresh water versus time for concentration 287 gm/l, at 2 ᵒ c fig. 7, height of fresh water versus time for concentration 350 gm/l, at 2 ᵒ c fig. (8). flux of fresh water versus nacl concentrations, at 2 ᵒ c also in figs. 2 7, it can be seen that increasing the velocity of pump leads to further decrease in the height of the fresh water column and this leads to an increase in water flux as shown in fig. (8) and this increase is relatively greater at higher brine solution concentrations. the increase in the measured water flux with increasing pump velocity is ascribed to the reduced impact of the ecp and icp in brine solution side. a similar observation was noticed in the experimental study of loeb [4]. effect of velocity on membrane permeability coefficient (a) the permeability coefficient (a) was calculated from equation (14) for each concentration used in experiments as shown in table (1). = a ∆π …(14) we notice from table (1) that the permeability coefficient (a) is almost constant for all concentrations in fo processes and the permeability coefficient (a) is more stable when increasing velocity, as a result of reducing the impact of ecp. experimenting with dupont b-9 (flat sheet) and b-10 (hollow fiber) permasep ro membranes, mehta and loeb [5] pointed out that a is not constant in fo; it declines with increasing osmotic pressure (i.e., increasing concentration) of the draw a study of water flux through forward osmosis membrane using brine\fresh water system 16 ijcpe vol.14 no.4 (december 2013) -available online at: www.iasj.net solution. the decline of a was explained by partial drying or osmotic dehydration of the membrane at high osmotic pressures. this is not entirely, true because the membrane permeability coefficient is a fixed property for each membrane and not affected by concentration change. table 1, effect of velocity on permeability coefficient (a) at brine concentrations of 98, 161, 224, 287 and 350 gm/l respectively using equation (14) (kg/(hr. .kpa)) concentration gm/l a at u=0 ml/sec. a at u=4 ml/sec. a at u=8 ml/sec. a at u=12 ml/sec. 98 1.70e-04 2.63e-04 2.10e-04 2.5e-04 161 1.60e-04 1.93e-04 1.62e-04 2.43e-04 224 1.60e-04 1.84e-04 2.10e-04 2.42e-04 287 1.20e-04 1.75e-04 1.78e-04 2.43e-04 350 1.22e-04 1.36e-04 1.71e-04 2.30e-04 comparison of membrane permeability coefficient (a) between experimental work and mathematical model the present mathematical treatment is subjected to comparison with the experimental work as shown below, figures (9) to (16) show comparison between the mathematical model and experimental results. fig. 9, membrane permeability coefficient (a) verses brine solutions concentrations fig. 10, membrane permeability coefficient (a) verses brine solutions concentrations fig. 11, membrane permeability coefficient (a) verses brine solutions concentrations fig. 12, membrane permeability coefficient (a) verses brine solutions concentrations in figs. (9) to (12) we note the difference between the mathematical model and experimental work, the reason is that the mathematical model did not take into account the effect of polarization and assumed perfect conditions. the values of a obtained from the model is, on average, about 7 times adel a. al-hemiri and marwah m. kamil -available online at: www.iasj.net ijcpe vol.14 no.4 (december 2013) 17 greater than those obtained from experimentation. in order to include the effect of polarization in the model, a correction factor is introduced into the model. this correction factor was found by calculating the average of the ratio for all runs. the resulting modified model is given by equation (15) below, z = + ( ) [exp. [ ( ) . t] -1] ...(15) figures (13) to (16) show the comparison between the mathematical and experimental work after adding the correction factor. fig. 13, membrane permeability coefficient (a) verses brine solutions concentrations fig. 14, membrane permeability coefficient (a) verses brine solutions concentrations fig. 15, membrane permeability coefficient (a) verses brine solutions concentrations fig. 16, membrane permeability coefficient (a) verses brine solutions concentrations conclusions after studying the experimentally detected performance of the tfc koch membrane one may conclude the followings: 1. the effect of polarization can be reduced by providing sufficient circulation. 2. the high value of water flux can be obtained by using high concentration of draw solutions. 3. the membrane permeability coefficient is constant, not affected by change in concentration of draw solution but it is affected by change in circulation velocity. 4. the present mathematical model has been tested using the present experimental results under fo conditions and shown to be 90% confident. a study of water flux through forward osmosis membrane using brine\fresh water system 18 ijcpe vol.14 no.4 (december 2013) -available online at: www.iasj.net nomenclature a(kg/m².hr.kpa) (kg/hr. ) u (ml/sec) m (kg/kgmole) t (sec) r(kpa.l/k.mole) t (c) c (kmole) greek letters δπ(pa) ρ (kg/ ) membrane permeability coefficient water flux across membrane velocity molecular weight time gas constant temperature concentration difference of osmotic pressure of the bulk solutions density references 1baker r. w., (2004)," membrane technology and applications ", johne wiley and sons, 2nd edition, p.p. 14-174. 2jeffrey r., robert l. and menachem ne., (2006)," desalination by ammonia–carbon dioxide forward osmosis: influence of draw and feed solution concentrations on process performance", journal of membrane science, vol. 278, p. p. 114-123. 3gordon t, jeffrey r and menachem e., (2006)," internal concentration polarization in forward osmosis: role of membrane orientation", desalination, vol. 197, p. p. 1-8. 4loeb s., (1976), "production of energy from concentrated brines by pressure-retarded osmosis i. preliminary technical and economic correlations", journal of membrane science, vol. 1. 5mehta g. d. and s. loeb, (1979), "performance of permassep b-9 and b-10 membranes in various osmotic regions and at high osmotic pressures", journal of membrane science, vol. 4, p. p. 335-349. 6kamil m. m., (2013), "a study of water flux through forward osmosis membrane using brine/fresh water system", msc thesis, chemical engineering department, of the college of engineering, university of baghdad. iraqi journal of chemical and petroleum engineering vol.15 no.4 (december 2014) 67-08 issn: 1997-4884 influences of operating variables on hydrodynamic performance of plunging water jet downflow bubble column yasser i. abdulaziz a, *, issam k. salih b and thamer j. mohammed b a,* chemical engineering department, al-nahrain university, baghdad, iraq b chemical engineering department, university of technology, baghdad, iraq abstract the hydrodynamics of a co-current down flow bubble column has been investigated with air – water system. a perspex bubble column of 5cm in diameter and 1.5m height is used as a test contactor using nozzles of 7, 8 and 9 mm diameter for airwater distributing. the column is provided with three electro-resistivity needle probes for bubble detection. experimental work is carried out with air flow rates from 0.09 to 0.45 m 3 /hr and liquid flow rates from 0.65 to 1.1m 3 /hr in order to study the effects of superficial gas velocity, nozzle diameter and liquid flow rate on the characteristics of hydrodynamic interactions viz. gas hold up, bubble diameter and bubble velocity by using two technical methods, direct height measurements for air-water mixture in the column and resistivity probe techniques. gas hold up is found to be progressively increased with increasing superficial gas velocity and with decreasing liquid flow rate. lower gas hold up is obtained with smaller nozzle diameter. however, gas hold up in two-phase zone is considerably higher than the corresponding value in mixing zone. the mean bubble velocity is increased with increasing superficial gas velocity, liquid flow rate and nozzle diameter for both mixing and two phase zones. experimental data are found to be fairly fitted with the drift flux model of zuber and findly. the bubble diameter is considerably increased with increasing superficial gas velocity and with decreasing liquid flow rate, whereas it is slightly influenced by nozzle diameter. however, the bubbles in two-phase zone are relatively bigger than those observed in mixing zone. finally, mathematical correlations have been developed from the experimental data to describe the gas hold up and bubble velocity in the uniform two-phase zone. keywords: gas hold-up, bubble velocity, bubble size, down-flow bubble column, plunging jet. introduction bubble column is a unit in which gas stream is dispersed in the continuous liquid phase as fine bubbles. there are many chemical and biochemical processes, viz. hydrogenation, oxidation, fermentation, petroleum refining, coal liquefaction etc, in which the overall production rate is often controlled by gas-liquid mass iraqi journal of chemical and petroleum engineering university of baghdad college of engineering influences of operating variables on hydrodynamic performance of plunging water jet downflow bubble column 68 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net transfer (1) . the reaction rate for such types of processes is proportional to the interfacial area, which is available for mass transfer. however, large interfacial area will be obtained if the gas is dispersed into the liquid phase as fine bubbles. numerous studies on the design and development of gas-liquid contacting equipment show that contactors or reactors belonging to the jet-mixing category with co-current or countercurrent contacting of phases such as nozzles, venturies and ejectors are going to be attractively important now a days due to the higher interfacial area and mass transfer coefficients obtained in such systems (2) . in general, the kinetic energy of fluid is used to achieve fine dispersion and mixing between phases in all co-current flow devices. the downflow bubble columns with plunging jet system have been highly recommended for chemical processes particularly wherein interfacial mass transfer area is the rate controlling step. considerable work has been reported by different authors on efficient dispersion of gas by liquid jet in gasliquid two-phase co-current contactor with nozzles, venturies and ejectors as gasliquid mixing devices (3,4) . several aspects of gas entrainment phenomena by plunging jet are reviewed in the experimental and theoretical studies, where the downcomer section of the plunging jet bubble column is commonly consisted of four main regions, namely the free jet, plunging jet, mixing zone and uniform two-phase flow zone (5) . gas holdup is the most important parameter that can be used to evaluate the hydrodynamic performance of bubble columns. it represents the percentage by volume of gas in two or three phase mixture. the overall gas holdup under two phase steady operation can be calculated according to the relation: m lm g h hh   … (1) where hm and hl are the total gas – liquid mixing height, and the corresponding clear liquid height respectively. gas holdup in two phase system gives the volume fraction of each phase and also determines the interfacial area between the gas and the liquid phases. early work for evaluation of gas holdup of co-current two phase flow in horizontal pipe under different flow conditions was carried out by lockhart and martinelli (6) . gas holdup in vertical upflow of air-water mixture using either a gas or liquid jet ejector was studied by mitra et al. (7) . however, kazumori et al. (8) used plunging water jet in air without downcomer section and observed tow correlations of gas holdup for laminar and turbulent jet velocities. briens et al. (9) studied venture bubble column with both downflow and upflow modes. they obtained much higher gas holdup (0.15-0.4) in downflow compared to upflow (0.08-0.12). however, deckwer (10) showed that gas distributor and physical properties of fluid have some further effect on gas holdup. havelka et al. (11) and akosman et al. (12) showed that gas holdup depends upon the superficial gas velocity and physical properties of gas and liquid. on the other hand, dema et al. (13) observed about 69-80% enhancement in gas holdup by using two venture ejectors positioned between the nozzles. the present work is aimed to study the air entrainment by using plunging water jet in co-current downflow bubble column. gas holdup, bubble velocity and bubble diameter have been evaluated for air-water system under different rates of both phases yasser i. abdulaziz , issam k. salih and thamer j. mohammed -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 69 using nozzles of 7, 8 and 9mm diameters. 2. experimental 2.1. experimental apparatus a perspex column of 50 mm diameter 152 cm length is used as a test contactor as shown in figure 1. the upper end of the contactor is connected to the brass nozzle. three electroresistivity probes, p1p3, are located at different positions along the column, in order to give hydrodynamic measurements for the three expected zones throughout the column. the electrodes are connected to the interface to compute of number, size, and the speed of the bubbles at specified working time. a rectangular perspex vessel of 320 × 320 mm size and 900 mm height has been used as air-liquid separator. the separator is provided with two outlet points for venting gas and draining liquid. a straight glass tube, l, has been connected between the lower part of the separator and the top of the column for measuring the height of clear liquid corresponding to the twophase height in the column. 2.2. experimental procedure and observations the selected nozzle and extended pipe line contactor is fitted properly before each experimental run to achieve an axially symmetric liquid jet. water is pumped from the storage tank (t) via a centrifugal pump and it is substantially emerged from the nozzle and flows downward through the center of the pipeline contactor. the valves v4 and nv2 are initially kept fully open and liquid jet directly hits the bottom of the air-water separator and then returns to the storage tank through valve v4. the valve v4 is then closed and the liquid is allowed to flow as a jet and accumulated in the separator. when the separator is filled with water to a certain height, the valve opening is adjusted to maintain the height in the separator at the desired fixed level. this process is continued so that the liquid level is increased until touches the end of the column, and a sudden change in the process is reached. meanwhile, the accumulated liquid in the column is directly increased and the liquid level could be fixed by adjusting the valve v4. two distinct zones are clearly observed, viz., the intense gas-liquid mixing zone followed by a downflow fine bubble zone. the pressure in the upper space of the separator can be increased by controlling the gas-flow rate from the separator through the valve v4 so that the level of gas-liquid mixture in the column should be still at the desired point. the operation range is limited so that the height of the two-phase mixture should not go up to the end of the contactor. when the operation is at steady state at certain gas and liquid flow rates the overall gas holdup can be obtained by measuring the total gas-liquid mixing height (hm) in the contactor and the corresponding clear liquid height (hl) in the arm (l), as in equation (1). 2.3. bubble monitoring and analyzing system the resistivity probe technique (14,15) is used in the present work to measure the local gas void fraction, bubble velocity, number and the size of bubbles. this measuring system consists of double sensor probe, interface, computer and software program (visual basic). influences of operating variables on hydrodynamic performance of plunging water jet downflow bubble column 70 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net c contactor n nozzle gr gas rotameter l arm of clear liquid pg1-pg2 pressure gauges pu pump r rotameter se separator nv1-nv2 needle valves t storage tank v1-v4 valves sv stabilizer vessel p1-p3 probes gc compressor if interface pc computer fig. 1: schematic diagram of the down-flow bubble column 3. results and discussion 3.1. gas holdup by height measurements the effect of superficial gas velocity on the overall gas holdup with nozzles of 7, 8 and 9mm diameter are properly illustrated in figures 2, 3 and 4 respectively. these figures indicate that gas holdup is progressively increased with increasing superficial gas velocity at a constant liquid flow rate. the values of gas holdup are generally ranged between (0.2-0.53) which are significantly higher than those reported by other workers (9,16) .these results may be explained according to the fact that the gas bubbles in co-current downflow system are moved against their higher buoyancy force, so that the bubbles have a higher slip velocity compared to upflow system. accordingly, the bubbles have longer residence time and hence higher gas holdup is observed. it is worthy to mention that, bubble flow is characterized by the dispersion of bubbles and the free space available between them. if the bubbles are small enough (db< 3 mm) and there is sufficient free spaces between them, the bubbles population increases considerably with increasing gas flow rate and hence gas holdup increases (12) . however, the gas flow rate has little effect on bubble population beyond certain limit and coalescence of bubbles is significantly increased, so the gas holdup remains constant (17, 18, 19) . 0 0.2 0.4 0.6 0.8 0 0.02 0.04 0.06 0.08 vg (m/s) g a s h o l d u p liquid flowrate 0. 65m^3/ hr liquid flowrate 0. 8m^3/ hr liguid flowrate 095m^3/ hr liquid flowrate 1. 1m^3/ hr g c s v n v2 gr p g 2 p g 1 p1 p2 c p 3 i f pc t l r v 2 s e v 4 n v 1 v 3 p u v 1 n yasser i. abdulaziz , issam k. salih and thamer j. mohammed -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 71 fig. (2) variation of overall gas holdup with superficial gas velocity at different liquid flow rates with nozzle of 7 mm diameter fig. 3 variation of overall gas holdup with superficial gas velocity at different liquid flow rates with nozzle of 8 mm diameter fig.4 variation of overall gas holdup with superficial gas velocity at different liquid flow rates with nozzle of 9 mm diameter it is important to note that bubbles observed in the present work for co-current downflow system, are relatively of bigger size (around 2-4 mm diameter) compared to those observed by other workers (around 1-2 mm diameter) which can be related to the higher duration of bubbles in the column. consequently, higher gas holdup will obtain. a comparative view of gas holdup obtained by different authors with different flow arrangements and over ranges of gas and liquid flow rates is given in table 1. it is important to note from table 1. that the values of the average gas holdup in upflow system are comparatively lower than those reported for downflow arrangement. bando et al. (20) observed a maximum gas holdup around 0.32 in downflow bubble column with simultaneous gasliquid injection nozzle system. similarly, yamagiya et al. (21) and ohkawa et al. (22) obtained the maximum value of around 0.4 in downflow system but the superficial gas velocities in their experiments were much higher than those observed in the present work. however, a relatively higher gas holdup (0.2-0.53) was obtained in the present work with air-water system even at low gas flow rate. hence, this system with proposed operating conditions can be alternatively used in chemical processes wherein interfacial area plays a dominating role. moreover, it is clearly seen from the aforementioned plots that gas holdup is progressively increased with decreasing liquid flow rate at the same superficial gas velocity. this is obviously related to the higher slip velocity of the bubbles and increasing their residence time in the contactor, so that the gas holdup increases to a certain limit. table (1) comparative view of gas holdup of the present work with the results of other studies authors type of flow column diameter (m) liquid tested liquid velocity vl (m/s) gas velocity vg (m/s) gas holdup εg (-) godbole et al. (17) batch with gas upflow 0.1 cmc 0.05-0.3 0.1-0.28 schumpe & co-current 0.1-0.14 cmc, (00.0030.03-0.2 0 0.2 0.4 0.6 0.8 0 0.02 0.04 0.06 0.08 vg(m/s) g a s h o ld u p liquid flowrate 0. 65m^3/ hr liquid flowrate 0. 8m^3/ hr liguid flowrate 0. 95m^3/ hr liquid flowrate 1. 1m^3/ hr 0 0.2 0.4 0.6 0.8 0 0.02 0.04 0.06 0.08 vg (m/s) g a s h o ld u p liquid flowrate 0. 65m^/ hr liquid flowrate 0. 8m^3/ hr liguid flowrate 0. 95m^3/ hr liquid flowrate 1. 1m^3/ hr influences of operating variables on hydrodynamic performance of plunging water jet downflow bubble column 72 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net deckwer (18) upflow 1.8) wt %. 0.025 khatib & richardson (23) co-current upflow 0.039 kaolin suspension 0.3050.61 0.3-3.5 0.15-0.55 ohkawa et al. (22) co-current downflow 0.02-0.026 water 0.05-0.2 0.05-0.2 0.01-0.4 bando et al. (20) co-current downflow 0.07 water 0.10-0.2 0.01-0.10 0.01-0.32 yamagiya et al. (21) co-current downflow 0.034-0.07 water 0.40.912 0.1-0.5 0.15-0.4 das et al. (24) co-current horizontal 0.019 cmc (0.5-1.00) kg/m 3 0.1411.00 0.067-1.55 0.1-0.4 das et al. (25) co-current upflow 0.019 cmc (0.5-1.00) kg/m 3 0.291.00 0.17-1.6 0.12-0.45 zahradnik et al. (19) co-current upflow 0.29 water 0.0080.029 0.0040.076 0.05-0.24 present work co-current downflow 0.05 water 0.0910.155 0.0120.063 0.2-0.53 on the other hand, the effect of nozzles diameter on the overall gas holdup at different liquid flow rates are shown in figures (4) and (5) for lower and higher liquid flow rates respectively. however, results are found with higher flow rates represented elsewhere (26) . it is clearly observed from these plots that lower gas holdup is obtained with smaller nozzle diameter throughout the operating range of gas velocity under any specific liquid flow rate. this result can be explained according to the fact that nozzle with smaller diameter produces bubbles of relatively small size which move downward faster due to lower buoyancy force. this result is in quite agreement with the observation of bando et al. (20) who showed similar trend of gas holdup variation in co-current down flow bubble column with simultaneous gas liquid injection nozzle system. fig. 4 variation of overall gas holdup with superficial gas velocity using nozzles of different diameters at liquid flow rate of 0.65 m 3 /hr. fig.5 variation of overall gas holdup with superficial gas velocity using nozzles of different diameters at liquid flow rate of 1.1 m 3 /hr 0.2 0.4 0.6 0 0.02 0.04 0.06 0.08 vg (m /s) g a s h o ld u p ( ) nozzle 7mm nozzle 8mm nozzle 9mm 0.1 0.3 0.5 0 0.02 0.04 0.06 0.08 vg (m/s) g a s h o ld u p ( ) nozzle 7mm nozzle 8mm nozzle 9mm yasser i. abdulaziz , issam k. salih and thamer j. mohammed -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 73 3.2. gas holdup by resistivity probe technique the variation of local gas holdup, measured by resistivity probe, with superficial gas velocity at different liquid flow rates with nozzle of 9mm diameter for both mixing and twophase flow zones are shown in figures (6)-(7) respectively. however, plots are observed with other nozzles and presented elsewhere (26) . these plots are apparently similar to those of overall gas holdup, i.e. the local gas holdup is progressively increased with increasing the superficial gas velocity. on the other hand, it is important to note that the values of gas holdup in two-phase zone is considerably higher than the corresponding values in mixing zone for specific gas and liquid flow rates. this observation is attributed to the generation of fine and relatively small size bubbles in mixing or intensing zone so that the buoyancy force and the residence time is being lower in this zone. accordingly, the gas holdup in mixing zone is evidently lower than the corresponding values in two-phase zone. it is important to mention that the overall gas holdup represents the average of the values of local gas holdup throughout the column. consequently, the values of the overall gas holdup determined by height measurement are approximated and in between the values of local gas holdup obtained by the resistivity probe technique. fig. 6 variation of local gas holdup measured by resistively probe with superficial gas velocity for "mixing zone" at different liquid flow rates with nozzle of 9mm diameter fig.7 variation of local gas holdup measured by resistively probe with superficial gas velocity for "two-phase zone" at different liquid flow rates with nozzle of 9mm diameter 3.3. correlation of gas holdup mathematical correlation has been developed from the experimental data by dimensional analysis to predict gas holdup within dispersed phase in terms of physical, dynamic and geometric variables of the system. gas holdup can be expressed as function of the following parameters; ( ) ... (2) the following correlation for estimation of gas holdup is observed: 0 0.2 0.4 0.6 0.8 0 0.02 0.04 0.06 0.08 vg (m/s) g a s h o ld u p liquid f low rate 0. 65m^3/hr liquid f low rate 0. 8m^3/hr liguid f low rate 0. 8m^3/hr liquid f low rate 1. 1m^3/hr 0 0.2 0.4 0.6 0.8 0 0.02 0.04 0.06 0.08 vg (m/s) g a s h o ld u p liquid f low rate 0. 65m^/hr liquid f low rate 0. 8m^3/hr liguid f low rate 0. 95m^3/hr liquid f low rate 1. 1m^3/hr influences of operating variables on hydrodynamic performance of plunging water jet downflow bubble column 74 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net       144.0277.0699.0 rere16.102  rglng a ... (3) where:reln is reynolds number of liquid based on nozzle diameter, reg is reynolds number of gas based on column diameter, and ar is nozzle to column area ratio. numerical analysis is applied on the experimental data observed under different operating conditions and statistical evaluation parameters of equation (3) gives correlation coefficient = 0.995412 with variance of 0.974982. the calculated values of gas-holdup according to equation (3) are plotted against the corresponding experimental values obtained by height measurement technique as shown in figure (8). this plot evidently indicates that most of the data are fitted the suggested correlation, and are exactly located on the diagonal with uniform and very little scattering. 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 predicted gas holdup 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 e x p e r im e n ta l g a s h o ld u p fig.8 graphical evaluation of gas holdup correlation 3.4. bubble velocity the variations of bubble moving velocity with superficial gas velocity at different liquid flow rates with 9mm nozzle diameter for both two-phase and mixing zones are shown in figures (9) and (10) respectively. however, similar results have been obtained with other nozzles, and were presented elsewhere (26) . fig.9 variation of mean bubble velocity with superficial gas velocity at different liquid flow rates with nozzle of 9mm diameter for (twophase zone region) 0.16 0.18 0.2 0.22 0.24 0.26 0.28 0 0.02 0.04 0.06 0.08 superficail gas velocity ( m/s) m e a n b u b b le v e lo c it y ( m /s ) liquid f low rate 0.65m^3/hr liquid f low rate 0.8 m^3/hr liquid f low rate 0.95m^3/hr liquid f low rate 1.1 m^3/hr yasser i. abdulaziz , issam k. salih and thamer j. mohammed -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 75 fig.10 variation of mean bubble velocity with superficial gas velocity at different liquid flow rates with nozzle of 9mm diameter for (mixing zone region) these figures indicate that bubble moving velocity is linearly increased with increasing superficial gas velocity. this increasing is analyzed by the well known drift flux model of zuber and findlay (27) . this model is expressed as:   dlgb vvvcu  0 … (4) where ub is the mean bubble velocity. vg & vl are the superficial gas and liquid velocities respectively. vd is the mean gas drift velocity. co is the distribution parameter. the sum of superficial gas and liquid velocities is often termed as gasliquid mixture velocity (vm). accordingly, equation (4) can be rewritten as: dmb vvcu  0 … (5) zuber and findlay equation represents a straight line relationship between the mean bubble velocity (ub) and the gas-liquid mixture velocity (vm). the slope of this line represents the distribution parameter, c0, which accounts the effect of the flow irregularity and concentration profiles; whereas the intercept is being the mean gas drift velocity, vd which accounts for the effect of local relative velocity and it is equivalent to unhindered bubble rise velocity, vb,∞. the experimental data for the uniform two-phase zone are plotted according to equation (5) as shown in figure (11). the data points seem to be uniformly distributed around the straight line with little scatter. statistical evaluation (5) gives correlation coefficient of 0.926 with variance of 0.857. the distribution parameter ( c0 ) is 0.76 and the mean gas drift velocity ( vd ) is 0.0622 m/s. according to these correlation coefficients, an empirical equation has been found as: … (6) where: ub is the mean bubble velocity and vm is superficial velocity of gas – liquid mixture. 0.17 0.19 0.21 0.23 0.25 0.27 0.29 0 0.02 0.04 0.06 0.08 superficial gas velocity (m/s) m e a n b u b b le v e lo c it y ( m /s ) liquid f low rate 0.65m^3/hr liquid f low rate 0.8 m^3/hr liquid f low rate 0.95m^3/hr liquid f low rate 1.1m^3/hr influences of operating variables on hydrodynamic performance of plunging water jet downflow bubble column 76 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net 0.08 0.12 0.16 0.20 0.24 vm (m /sec) 0.12 0.16 0.20 0.24 u b ( m /s e c ) fig.11 zuber – findaly correlation plot for the uniform two – phase zone this result proves that the present data satisfactorily fits zuber and findlay equation. it is clearly shown that the distribution parameter is less than unity i.e. 0.76. zuber and findlay (27) agreed that velocity profile becomes flatter with increasing liquid flow rate which leads to reduction in the value of co so that its value is apparently less than unity. this result indicates that gas phase is uniformly dispersed across the column area. on the other hand, when the value of co becomes more than unity, it gives an indication for parabolic velocity profile so that the centerline velocity is higher than the mean velocity and the gas phase is preferably aggregated in the center of the column. numerous investigators (28, 21, 25, 29) have attempted to quantify the values of the distribution parameter and drift velocity. their results are found to be in good agreement with the results of the present work. on the other hand, figures (9) to (10) reveal that bubble velocity in mixing zone is higher than that in the uniform two-phase zone at any specific liquid flow rate and nozzle diameter. this result is undoubtedly ascribed to the bubble size. it is well known that smaller bubbles are often found in mixing zone which has lower buoyancy force and higher velocity comparing with relatively larger bubbles that commonly exist in uniform two-phase flow zone. 3.5. bubble diameter the variations of bubble diameter with superficial gas velocity at different liquid flow rates with nozzle 7mm diameter shown in figures (12) and (13) for both two-phase and mixing zones respectively. however, same plots are appeared with other nozzles, and are presented elsewhere (26) . yasser i. abdulaziz , issam k. salih and thamer j. mohammed -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 77 fig. 12 variation of bubble diameter with superficial gas velocity at different of liquid flow rates with nozzle of 7mm diameter for two-phase zone fig. 13 variation of bubble diameter with superficial gas velocity at different liquid flow rates with nozzle of 7 mm diameter for mixing zone it can be seen from these plots that the measured bubble diameter is considerably increased with increasing superficial gas velocity at any specific liquid flow rate. the result is attributed to the increasing of the volume of mixing zone with increasing the superficial gas velocity, while the energy input from the jet remains constant. accordingly, the energy input per unit volume will be decreased and resulting an increase in the bubble diameter. moreover, these figures indicate that bubble diameter is progressively increased with decreasing liquid flow rate. this result is ascribed to the energy input at plunging jet which is proportional to the square of the jet velocity. the inertia force created by the jet is intuitively increased with increasing liquid flow rate. the higher downflow liquid stream prevents the bubble coalescence, so that small bubbles will be produced. on the other hand, these plots reveal that bubble diameter is slightly influenced by the nozzle size. however, nozzle with small diameter relatively produces small size bubbles. this is ascribed to the higher energy input by the jet stream with small size nozzle at any specific liquid flow rate i.e. more inertia will input to the system which generates small bubbles. however, an interesting observation can be seen in figure (12) for twophase flow region. the increasing of bubble diameter with increasing superficial gas velocity is being more significant at intermediate range of velocity, viz., between 0.02-0.04 m/sec. thereafter, the increasing in bubble diameter is extremely limited i.e. the bubble diameter seems to be stable and less dependent on superficial gas velocity. this result can be explained according to the fact that bubble diameter increases to a certain limit with increasing superficial gas velocity. population of bubbles facilitates the coalescence with each other to give comparatively larger bubbles. the bubbles become more stable beyond a specific size due to the balance exists between the buoyancy force of bubbles and the force of downflow stream of liquid, hence the coalescence of bubbles is highly restricted. the values of bubble diameter observed in the present work are ranged between 2-4 mm which are similar to the result of jonathan et al. (30) , who observed bubbles of 3-4 1.5 1.9 2.3 2.7 3.1 3.5 0 0.02 0.04 0.06 0.08 superficial gas velocity(m/s) b u b b l e d i a m e t e r ( m m ) liquid f low rate 0.65m^3/hr liquid f low rate 0.8m^3/hr liquid f low rate 0.95m^3/hr liquid f low rate 1.1m^3/hr 1 1.4 1.8 2.2 2.6 3 0 0.02 0.04 0.06 0.08 superficial gas velocity (m/s) b u b b l e d i a m e t e r ( m m ) liquid f low rate 0.65m^3/hr liquid f low rate 0.8m^3/hr liquid f low rate 0.95m^/hr liquid f low rate 1.1 m^3/hr influences of operating variables on hydrodynamic performance of plunging water jet downflow bubble column 78 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net mm diameter using an acoustic monitoring technique for air-water system. however, mandal et al. (29) observed bubbles of larger size, viz., 35 mm diameter for down flow bubble column with air-water system. conclusion three dispersion zones are distinguished according to the visual observation: (1) the top mixing zone where the liquid jet plunges with the simultaneous formation and the breakup of gas bubbles, (2) the middle zone of a homogeneous bubbly flow and higher gas hold up of bigger bubbles, and (3) the bottom zone wherein a decrease in bubble population and gas hold up. gas hold up is found to be progressively increased with increasing superficial gas velocity and with decreasing liquid flow rate. lower gas hold up is obtained with smaller nozzle diameter at any specific liquid flow rate throughout the operating range of gas velocity. a significant back mixing is particularly observed in the plunging zone which leads to the regeneration of fine gas bubbles and enhances the overall gas hold up compared with up flow systems. the following correlation is developed by dimensional analysis for estimation of gas holdup: ( ) the mean bubble velocity is linearly increased with increasing superficial gas velocity. the data satisfactorily fit the drift flux model of zuber and findlay according to the relation: the mean bubble velocity is apparently increased with increasing liquid flow rate and nozzle diameter for both mixing and two – phase zones. however, it is found that the mean bubble velocity in mixing zone is evidently higher than that in two-phase zone at any specific liquid flow rate and nozzle diameter. the bubble diameter is considerably increased with increasing superficial gas velocity, whereas it is slightly influenced by nozzle size. moreover, bubble diameter is found to be progressively increased with decreasing liquid flow rate. however, the bubbles in the two-phase zone are relatively bigger than those observed in the mixing zone. notation ar nozzle to column area ratio, (dn/dc) 2 , dimensionless dc diameter of the column , m. dn diameter of the nozzle , m. hm total gas-liquid mixing height, m. qg volumetric flow rate of gas , m 3 /s. ql volumetric flow rate of liquid , m 3 /s. qr volumetric flow rate of gas to liquid , qg/ql ,dimensionless. re g reynolds number of gas based on column diameter, , dimensionless. re ln reynolds number of liquid based on nozzle diameter, , dimensionless. ub mean bubble velocity, m/s. vg superficial velocity of gas phase , m/s vl superficial velocity of liquid phase, m/s. vm superficial velocity of gas – liquid mixture, m/s. greek symbols εg gas holdup , dimensionless µg viscosity of gas , kg/m.s µl viscosity of liquid , kg/m.s ρg density of gas , kg/m 3 ρl density of liquid , kg/m 3 εg gas holdup , dimensionless yasser i. abdulaziz , issam k. salih and thamer j. mohammed -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 79 references 1azzopardi, b.j., mudde, r.f., lo, s., morvan, h., yan, y. and zhao, d. (2011) "hydrodynamics of gasliquid reactor" john wiley & sons, ltd. 1 st edition. 2 mandal, a., kundu, g. and mukherjee, d. (2005) "comparative study of two phase gas – liquid flow in ejector induced upflow and down flow bubble column " int. j. of chem. reactor eng. 3, a1-a13. 3majumder, s. k., kundu, g., mukherjee, d. (2006) " efficient dispersion in a modified two-phase non-newtonian down-flow bubble column" chem. eng. sci. 61, 6753 – 6764. 4 majumder, s. k. (2008) “analysis of dispersion coefficient of bubble motion and velocity characteristic factor in down and up flow bubble column reactor “ chem. eng. sci., 63 3160 – 3170. 5 bin, a. k (1993) "gas entrainment by plunging liquid jet" chem. eng. sci. 48, 3585-3630. 6 lockhart, r. w. and martinell , r.c. (1949) " proposed correlation of data for isothermal two – phase , two components flow in pipes " chem. eng. prog. 45 , 3948. 7mitra , a. k., pal , s.s. and roy , a.n. (1980) " pressure drop and holdup in vertical two-phase cocurrent flow with improved gasliquid mixing " ind. eng. chem. des. dev. 19 , 67-75. 8kazumori , f. , hsu , y. and kamogawa , t. (1988) " gas holdup and gas entrainment of plunging water jet with a constant entrainment guide " can. j. chem. eng. 66 , 1928. 9briens , c.l. , hwynh , l. x. , large , j. f. , catros , a. , benard , j. r. and bergougnou , m. a. (1992) "hydrodynamics and gasliquid mass transfer in a downward venturi – bubble column combination " chem. eng. sci. 47 , 3549-3556. 10deckwer , w. d. (1992) " bubble column reactors " wiley , new york. 11havelka , p. , linek , v. sinkule , j. , zahadrik , j. and fialova , m. (1997) " effect of the ejector configuration on the gas suction rate and gas holdup in ejector loop reactors " chem.. eng. sci. 52 , 1701-1713. 12akosman , c. , orhan , r. and dusun , g. (2004) "effects of liquid property on gas holdup and mass transfer in cocurrent downflow contacting column " chem. eng. and proc. 43 , 503-509. 13dema , h. k. , abd , m. f. and halabia , e. k. (2007) "study hydrodynamics and mass transfer in impinging jet bubble column" tikrit j. of eng. sci. 14 , 102-134. 14van der welle, r. (1985) “void fraction, bubble velocity and bubble size in two – phase flow” int.j. multiphase flow, 11, 317-345. 15choi, k. h. and lee, w.k. (1990) "comparison of probe methods for measurements of bubble properties" chem. eng. commun. 91, 35-47. 16mouza , a. a. , dalakoglou , g.k. and paras , s. v. (2004) " effects of liquid performance of bubble column reactors with fine pore spragers " chem. eng. sci. 60 , 1465 – 1475. 17godbole , s. p. , honath , m. f. and shah , y.t. (1982) " holdup structure in highly viscous newtonian and non-newtonian liquids in bubble column " chem. eng. commun. 16, 119 – 134. 18schumpe, a. and deckwer, w. d. (1980) “analysis of chemical methods for determination of interfacial areas in gas-liquid dispersions with nonuniform bubble size” chem. eng. sci., 35, 2221-2233. influences of operating variables on hydrodynamic performance of plunging water jet downflow bubble column 80 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net 19zahradrik , j. fialova , m. , linek , v. , sinkule , j. , reznickova ,j. and kastanek , f. (1997) "dispersion efficiency of ejector type gas distributor in different operating models " chem. eng. sci. 52 , 4499-4510. 20bando , y. , uraishi , m. , nishimura , m., hattori , m. and asada , t. (1988) " cocurrent downflow bubble column with simultaneous gas – liquid injection nozzle " j. of chem. eng. of japan 21 , 607-612. 21yamagiya , k. kusabiraki , d. and ohkawa , a. (1990) " gas holdup and gas entrainment rate in downflow bubble column with gas entrainment by a liquid jet operation at high liquid throughput" j. chem. eng. japan 23 , 343-348. 22ohkawa, a., kusabiraki , p. , kawai , y. and sakai , n. (1986)"some flow characteristics of a vertical liquid jet system having down comers" chem. eng. sci. 41 , 23472361. 23khatib , z. and richardson , j. f. (1984) " vertical cocurrent flow of air and shear thinning suspensions of kaolin " chem. eng. res. des. 62 , 139-154. 24das, s. k. , biswas , m.n. and mitra , a.k. (1989) " pressure losses in two-phase gas non-newtonian liquid flow in a horizontal tube " j. pipelines 7, 307-325. 25das, s.k. , biswas , m.n. and mitra, a.k. (1992) " holdup for twophase flow gas non-newtonian liquid mixtures in horizontal and vertical pipes " can. j. chem. eng. 70 , 431-437. 26abdulaziz, y. i. (2008) "hydrodynamic interaction in gasliquid downflow bubble column with airwater system" ph.d. thesis, university of technology, baghdad. 27zuber ,n. and findlay, j. a. (1965) " average volume concetration in two-phase flow system" j. heat transfer, sec. c. 87 , 453-468. 28clark , n.n. , and flemmer , r. l. (1985) " predicting the holdup in two-phase bubble upflow and downflow using the zuber and findlay drift flux model " aiche j.31 , 500-503. 29mandal , a. , kundu , g. , mukherjee , d. (2003) " gas holdup and entrainment characteristics in a modified downflow bubble column with newtonian and non-newtonian liquid " chem. eng. and proc. 42 , 777-787. 30jonathan , w. r. , boyd , r. and varley , j. (2004) " acoustic emission measurements of low velocity plunging jets to monitor bubble size " chem. eng. j. 97 , 11-2 iraqi journal of chemical and petroleum engineering vol.18 no.1 (march 2017) 47 56 issn: 1997-4884 equilibrium, kinetic and thermodynamic study of aniline adsorption over prepared zsm-5 zeolite ammar s. abbas* and sally a. hussien *chemical engineering department – college of engineering – university of baghdad (iraq) *email: ammarabbas@coeng.uobaghdad.edu.iq abstract aniline and its derivatives are common contaminants in various wastewaters and represent a serious worry for societies health and a challenge to ecologists due to their dangers effects on to the human health. zsm-5 zeolite was prepared from locally available materials (kaolin and rice husk) for adsorption of aniline from synthetic wastewater. characterization of the prepared zsm-5, kinetics and thermodynamic of the adsorption process were investigated. the characterization results of the prepared zsm-5 zeolite showed that the surface area was 270.1 m 2 /g and pore volume 0.21828 cm 3 /g. the silica to alumina ratio (si/al) was 166. 47 and the sodium content was 11 wt. %. the atomic force microscope (afm) results showed that the average particle diameter of the prepared adsorbent was 70.71nm. langmuir isotherm better illustrated the adsorption process with maximum uptakes 8.3125 mg/g. whereas, kinetics results of the adsorption process showed it the pseudo-second order in different operating temperatures. the calculated values of δg showed that the adsorption process was spontaneous, while the δh results illustrated the process to be exothermic nature of this process with negative values of δs. key words: adsorption, aniline, zsm-5, zeolite, wastewater, kinetics, thermodynamic. introduction aniline is one of the supreme common contaminants found in wastes from the various industrial wastewater such as pharmaceutical, pesticide, dyestuff, petrochemicals, tanneries, distilleries, textile, paper and pulp mills, electroplating, food processing and agrochemical industries [1]. accordingly, the elimination of aniline from these effluents has become a social worry especially for the colored effluents. color being a visible pollutant, the water contaminated with aniline is not only unfit for drinking purpose due to transformation of hemoglobin to methemoglobin, which has a lower affinity for oxygen than hemoglobin, therefore decreases blood’s ability to transport oxygen, but is also not suitable for agriculture due university of baghdad college of engineering iraqi journal of chemical and petroleum engineering mailto:ammarabbas@coeng.uobaghdad.edu.iq equilibrium, kinetic and thermodynamic study of aniline adsorption over prepared zsm-5 zeolite 48 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net to its inhibitory action on photosynthetic process in plants [2], [3]. numerous methods are used to treat wastewater containing aniline such as oxidation, extraction, membrane separation, biochemical decomposition, and adsorption [3], [5], [6]. among all methods, the adsorption is the most effective way to remove aniline and such organics from wastewater. adsorption technique does crop harmful byproducts, and the recycling of both the adsorbent and pollutants is possible. one challenge met by adsorption technology is the discovery of new adsorbents like activated carbons, polymer resin, clays, mesoporous oxides and zeolite, that effectively eliminate organic pollutants, such as aniline, from aqueous solutions.[1], [2], [3], [7]. in the design and optimization of adsorption processes, the adsorption isotherms and kinetics are of greatest importance to study. adsorption isotherms are essential for the description of how adsorbate will interact with adsorbent and are in necessary optimizing the use of adsorbent. thus, the correlation of experimental equilibrium data using either a theoretical or an empirical equation is essential for adsorption performance assessment. adsorption kinetics involves the study of the rate at which pollutants are removed from aqueous solution onto adsorbent surface, which in turn controls the residence time of the adsorbate uptake at the solid-solution interface [8]. aim of the work the aim of this research is the removal of aniline from wastewater by prepared zsm-5 zeolite. characterization results of prepared zsm-5 zeolite adsorbent were discussed. the study the isotherm models of adsorption to identify the effect of temperature and time on the removal of aniline in a batch experiments was presented. finally, the study of kinetics and thermodynamics of the aniline adsorption over prepared zeolite in the best selected conditions, was illustrated. adsorption isotherms and thermodynamics langmuir isotherm the langmuir adsorption isotherm represented by equation 1, langmuir in (1918) …(1) where, ce is the equilibrium concentration (mg/l) of adsorbate (aniline) in the bulk; is the amount of adsorbate (mg/g) adsorbed at equilibrium. and ‘ ’ are langmuir constants related to adsorption efficiency and energy of adsorption, respectively [2]. freundlich isotherm freundlich in 1906 represented the adsorption isotherm as shown in equation 2: log = log + log …(2) where and have their usual meanings and the constants and n are measures of adsorption capacity and intensity of adsorption, respectively [2]. hill isotherm the hill equation (in, 1910) was postulated to describe the binding of different species onto homogeneous substrates defined as: …(3) http://www.iasj.net/ ammar s. abbas and sally a. hussien -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 49 where , nh, and qsh (mg/l) are hill isotherm constants, hill cooperatively coefficient of the binding interaction and hill isotherm saturation uptake. the model assumes that adsorption is a cooperative phenomenon by which ligand binding at one site of the macromolecule may influence different binding sites on the same macromolecule [9]. sips isotherm sips (in 1948) combined the langmuir and freundlich isotherm type models to describe heterogeneous surface much better. sips adsorption isotherm is given by the equation 4: …(4) where (mg/g) is the maximum adsorbed amount of adsorbate per unit mass of adsorbent, ((l/mg) ^1/m) is sips constant related to energy of adsorption, and parameter m could be regarded as the parameter characterizing the system heterogeneity [4]. redlich–peterson isotherm the redlich–peterson isotherm (in, 1959) is a hybrid isotherm featuring both langmuir and freundlich isotherms, which incorporates three parameters into an empirical equation given by: …(5) where (l/g) and (1/mg) are redlich–peterson isotherm constants, and g is the isotherm exponent. the model can be applied either in homogeneous or heterogeneous systems. it approaches the freundlich isotherm model at high concentration and in accordance with the low concentration limit it approaches the ideal langmuir condition [9]. toth isotherm the toth isotherm model (in, 1971) is another empirical equation developed to improve langmuir isotherm fittings. it is useful in describing heterogeneous adsorption systems, and satisfies both low and high-end boundary of concentrations: …(6) where kt (mg/g), (l/mg) is the toth isotherm constants. the correlation presupposes an asymmetrical quasi-gaussian energy distribution where most binding sites have an adsorption energy lower than the peak value [9]. adsorption kinetics [7], [12] 1pseudo_first order model the psedo first-order kinetic model can be represented as follow: …(7) integration of equation 7 for the boundary condition t=0 to t=t and qt=0 to qt=qt: …(8) where (mg/g) and (mg/g) are the amounts of adsorbed adsorbate at equilibrium and at time t respectively, and ( is the rate constant of pseudo first order equation. 2pseudo_second order model the pseudo second_order kinetic model can be represented as follows: …(9) http://www.iasj.net/ equilibrium, kinetic and thermodynamic study of aniline adsorption over prepared zsm-5 zeolite 50 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net integration equation 9 for the boundary condition t=0 to t=t and q=0 to q= : …(10) where (mg/g) and (mg/g) are the amounts of adsorbed adsorbate at equilibrium and at time t respectively, and (g/mg. min) is the equilibrium rate constant of pseudo second order model. 3intra_particle diffusion model the intra-particle diffusion kinetic model can be represented as follow: ⁄ …(11) where (mg/g) is the amount of solute on the surface of sorbent at time t, (mg/g. ⁄ ) is the intraparticle diffusion rate constant and c (mg/g) is the intercept adsorption thermodynamics adsorption thermodynamic is an important tool elucidating the adsorption behavior of an isolated system. its original concept assumes that energy cannot be gained or lost, and entropy changes. the values of enthalpy change (δh), gibbs free energy change (δg), and entropy change (δs) were computed using the following equation: …(12) δg = rt …(13) …(14) where r is the universal gas constant (8.314 j/mol. k), t is temperature (k), and is the distribution coefficient for the adsorption [10]. experimental work material the reactant materials used in this study were silica sio2 (purity 92%) molecular weight 60.08 g/mole as silica source, tetrapropylammonium hydroxide solution (tpaoh, c12h29no, 20% aqueous solution, merck) as direct template agent, sodium hydroxide (naoh, 98 wt%, merck) and kaolin as alumina source. zeolite preparation kaolin was sieved to a particle size ≤ 75µm. 4g of naoh was dissolved in 70 ml of distilled water and then divided in two portion. 29.8 g of sio2 were dissolved in one portion of sodium solution and stirred until clear solution was reached, after that was added 18.3 g of 20% of tpaoh to sodium silicate solution and stirred to 60 min. 1.7 g of kaolin (alumina source) was mixed with the another portion of sodium solution. silicate solution was slowly added to aluminate solution and stirred to 60 min. the mixture was placed in teflon-lined stainless steel autoclave at 150 c for 96 hr. the product obtained was filtered and washed with distilled water for several times until ph value dropped to 8.5 after that the product was dried in an electrical oven at 110˚c overnight and followed by calcination at 550 ˚c for 3 h. characterization and analysis of prepared zsm-5 zeolite the prepared catalyst was characterized by using different instrumental analysis techniques such as: x–ray diffraction (xrd), atomic force microscope (afm), bet specific surface area and pore volume by iso-9277-2010 method, sodium content by astm d-1428-64 method, and x-ray fluorescence (xrf) for determine the silica content and silica to alumina ratio. http://www.iasj.net/ ammar s. abbas and sally a. hussien -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 51 experimental procedure batch adsorption experiments were conducted in a set of 250 ml erlenmeyer flasks containing 0.05 g of zsm-5 zeolite per 10 ml of solution containing 60 mg/l of the aniline. the mixture was agitated in a thermostatic orbital shaker at room temperature with an agitation speed of 150 rpm. the aniline concentration in the supernatant was determined using a double beam uv–vis spectrophotometer (shimadzu uv160a, japan) at 280 nm. each experiment was carried out in triplicates under identical conditions and an average value was determined. qe (mg/g), was calculated by: [9] …(15) where co and ce (mg/l) are the liquid phase concentration of aniline at initial and equilibrium, respectively. v (l) is the volume of the solution, and the w (g) is the mass of adsorbent used [9]. results and discussion x-ray diffraction pattern was determined for prepared zsm-5 zeolite as shown in figure 1. the comparison between lattice spacing of prepared zsm-5 zeolite with standard synthetic one is shown in table 1. the comparison in the lattice spacing shows that the prepared zsm-5 zeolite is approximately comparable with the standard. fig. 1: xrd pattern of prepared zeolite-zsm_5 table1: comparison of lattice spacing between prepared zsm-5zeolite and standard synthetic zsm5zeolite prepared zsm-5 zeolite standard zsm-5 zeolite angle (2ɵ) deg. d, spacing (å) angle (2ɵ) deg. d, spacing (å) 7.453 11.85116 7.93 11.153 8.06 10.95828 8.01 11.033 8.95 9.86504 8.90 9.939 9.133 9.675 9.14 9.673 14.945 5.92300 14.99 5.909 15.612 5.67156 15.63 5.669 16.045 5.51930 16.07 5.517 19.157 4.62933 19.24 4.613 20.981 4.23063 20.94 4.242 23.200 3.83080 23.19 3.836 http://www.iasj.net/ equilibrium, kinetic and thermodynamic study of aniline adsorption over prepared zsm-5 zeolite 52 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net the silica to aluminum ratio (si/al) of zsm-5 zeolite was equal to 166.47 according to xrf analysis which lie in the range of si/al ratio of standard zsm-5 zeolite (10_∞). also, these results were in a good agreement with sari et al., [11] who mentioned that the ratio of silica to alumina in zsm-5is about 177. the bet surface area and pore volume of zsm-5 zeolite were 270.1 m 2 /g and 0.21828 cm 3 /g respectively with sodium content equal to 11 wt. %. the afm analysis was shown that the zsm-5 zeolite have average nano particle equal to 70.71 nm. adsorption isotherm the adsorption isotherms illustrate the interaction between the adsorbates and adsorbents. adsorption equilibrium is established when an adsorbate has been contacted with the adsorbent for enough time, and the adsorbate concentration in the bulk solution is in balance with the interface concentration [13]. the fitting of adsorption data isotherm models is a main step to find the appropriate model that can be used for design purposes. in this work, experimental equilibrium data for aniline adsorption on zsm-5 zeolite, calculated from equation 15, fitted to the langmuir and freundlich isotherms, equations 1 and 2 respectively. results are represented in figures 2 and 3. the results of this fitting, as summarized in table 2, show that langmuir isotherm has the highest value as compared to that freundlich isotherm. the langmuir model correlates the equilibrium data with (correlation factor) values of 0.9987 for aniline, suggesting the monolayer adsorption of aniline on zsm-5 zeolite. these results are in good agreement with [3]. for the langmuir isotherm, the values of (separation factor) are 0.0311 for aniline, which indicate the favorability of aniline adsorption on zsm-5 zeolite. also, table 2 shows that the langmuir isotherm gives maximum adsorption capacity of 8.3125 mg/g for aniline. fig. 2: langmuir adsorption isotherm of aniline on zsm-5 zeolite table 2: isotherm parameters for aniline adsorption on zsm-5 zeolite isotherm parameter temperature (k) 303 langmuir q, max(mg/g) kl (l/g) r 2 rl 8.3125 0.5196 0.9987 0.0311 freundlich kf ((mg/g)(l/g))1/n n r 2 -0.3480 2.6371 0.9228 0 0.5 1 1.5 2 2.5 3 3.5 0 5 10 15 20 25 c e /q e ( g /l ) ce (mg/l) http://www.iasj.net/ ammar s. abbas and sally a. hussien -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 53 fig. 3: freundlich adsorption isotherm of aniline on zsm-5 zeolite adsorption kinetics two kinetic models: pseudo first order and pseudosecond order models, equations 8 and 10, where used to correlate the experimental kinetic data of aniline on zsm-5 zeolite at different temperature. the pseudo first order equation is of low r 2 values as compared to the pseudosecond order equation, as shown in table 3. high deviation between the experimental and calculated adsorption capacity can be seen from this table. on the other hands, the linear plot of t/qt versus t figures 5 for pseudo second order equation has high r 2 values compared to pseudofirst order model. the results of this tables show that the adsorption kinetics data are better represented by pseudosecond order and the values of k2 increased with increasing solution temperature taking the values 0.02196, 0.0245 and 0.0280 for aniline at 303, 313 and 323 k respectively. on the contrary, the values of qe decreased with increasing temperature to 8.0515, 7.61035 and 7.0028 for aniline at 303, 313 and 323 k respectively. these results are in agreement with those reported by [1] and [7] for the adsorption of aniline. fig. 4: pseudofirst order kinetic for aniline on zsm-5 zeolite at different temperature 0 0.2 0.4 0.6 0.8 1 1.2 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 lo g q e log ce -2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 0 20 40 60 80 100 120 140 lo g (q e -q t) t (min) at 30 c at 40 c at 50 c http://www.iasj.net/ equilibrium, kinetic and thermodynamic study of aniline adsorption over prepared zsm-5 zeolite 54 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net fig. 5: pseudosecond order kinetic for aniline on zsm-5 zeolite at different temperature table 3: rate constant for aniline adsorption on zsm-5 zeolite temperature (k) pseudofirst order model qe, exp (mg/g) qe, cal (mg/g) k1 (1/min) r 2 303 7.6154 2.9289 0.0509 0.8309 313 7.2098 12.3851 0.0829 0.9163 323 6.7203 2.0003 0.0329 0.9204 temperature (k) pseudosecond order model qe, exp (mg/g) qe, cal (mg/g) k2(g/mg.min) r 2 303 7.6154 8.0515 0.02196 0.9977 313 7.2098 7.61035 0.0245 0.9983 323 6.7203 7.0028 0.0280 0.9996 adsorption thermodynamics according to eqs. 12 14. the values of δh, δs, and δg were determined from the slope and intercept by plotting versus as shown in figure 6. table 4 summarizes the thermodynamic parameters at different temperatures for the adsorption of aniline onto zsm-5 zeolite. the negative δh values 12630.6288 j/mole illustrate the adsorption process to be exothermic in nature. the δs values -37.0480 j/mole revealed decreasing randomness at the solution/solid interface during the adsorption of aniline onto zsm-5 zeolite. generally, the absolute magnitude of the change in free energy for physical adsorption is smaller than that of chemisorptions [15]. the obtained gibbs free energy (-δg) values were 1390.74, 1063.98, 647.876 (j/mol) at different temperatures 303, 313 and 323 k, respectively. the δg values were negative indicating that the adsorption process occurred spontaneously. because δg decreased with the increase of temperatures, it confirmed that adsorption more likely occured at lower temperatures. these results are in agreement with those reported [14]. table 4: thermodynamics parameter for adsorption aniline on zsm-5 zeolite 0 2 4 6 8 10 12 14 16 18 20 0 20 40 60 80 100 120 140 t/ q t (m in .g /m g ) t (min) at 30 c at 40 c at 50 c -δg(j/mole) 303 k 313 k 323 k δs(j/mole) δh(j/ mole) 1390.74 1063.98 647.876 -37.0480 -12630.6288 http://www.iasj.net/ ammar s. abbas and sally a. hussien -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 55 fig. 6: thermodynamic of adsorption aniline on zsm-5 zeolite conclusions according to the results obtained from this study, the following conclusions are obtained: 1. the characterization results, i.e silica to alumina ratio (si/al) 166. 47, surface area of 270.1m 2 /g, pore volume 0.21828 cm 3 / g and sodium content 11 wt% for prepared zsm-5 zeolite were in good with standard zsm-5 zeolite, therefore is possible to say that the prepared catalyst obtained from locally kaolin and rice husk in this work is zsm-5 zeolite. 2. the average diameter of particles of prepared zsm-5 zeolite determined by afm was 70.71 nm, and this means that this catalyst is nano type catalyst. 3. maximum aniline uptakes, as calculated from langmuir isotherm model was 8.3125 mg/. 4. the kinetics data were fitted to pseudosecond order kinetic model. 5. the thermodynamic parameters, δg values were negative from 1390.74 to 647.876 j/mol at different temperature, δh values was 12630.6288j/mole and δs values was -37.0480 j/mol k. references 1. h. al-johani and m. a. salam, “kinetics and thermodynamic study of aniline adsorption by multiwalled carbon nanotubes from aqueous solution,” j. colloid interface sci., vol. 360, no. 2, pp. 760–767, 2011. 2. d. k. tyagi and o. p. yadav, “equilibrium and kinetic studies on adsorption of aniline blue from aqueous,” vol. 2, no. 3, 2011. 3. t. m. albyati and a. m. doyle, “shape-selective adsorption of substituted aniline pollutants from wastewater,” no. 1, pp. 459–468, 2013. 4. ghaied, m.a. 2014,"microwave assisted preparation of activated carbon from phragmites(reed) for antibiotics adsorption", m.sc. thesis, college of engineering, baghdad university 5. l. i. u. zhipei, y. huifang, and z. peijin, “刘志培 杨惠芳 isolation and characterization of a bacterial strain for the degradation of aniline,” vol. 9, no. february, pp. 1173–1179, 1999. 6. t. m. albayati and a. m. doyle, “purification of aniline and nitrosubstituted y = 1519.2x 4.4561 0 0.1 0.2 0.3 0.4 0.5 0.6 0.00305 0.0031 0.00315 0.0032 0.00325 0.0033 0.00335 ln k d 1/t http://www.iasj.net/ equilibrium, kinetic and thermodynamic study of aniline adsorption over prepared zsm-5 zeolite 56 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net aniline contaminants from aqueous solution using beta zeolite,” vol. 23, no. 1, 2014. 7. t. m. al-bayati, “removal of aniline and nitro-substituted aniline from wastewater by particulate nanoporous mcm-48,” part. sci. technol., vol. 32, no. 6, pp. 616–623, 2014. 8. m. j. ahmed, s. k. theydan, and a. a. k. mohammed, “adsorption of phenol and p-nitro phenol onto date stones : equilibrium isotherms , kineticsand thermodynamics studies,” vol. 18, no. 6, 2012. 9. k. y. foo and b. h. hameed, “mesoporous activated carbon from wood sawdust by k2co3 activation using microwave heating,” bioresour. technol., vol. 111, pp. 425–432, 2012. 10. m. j. ahmed and s. k. theydan, “fluorouinolones antibiotics adsorption onto microporous activated carbon from lignocellulosic biomass by microwave pyrolysis,” j. chem. eng., pp. 209–226, 2014. 11. z. g. l. v. sari, h. younesi, and h. kazemian, “synthesis of nanosized zsm-5 zeolite using extracted silica from rice husk without adding any alumina source,” appl. nanosci., vol. 5, no. 6, pp. 737–745, 2015. 12. qiu, h., lv l. pan, b., zhang, q., zhang, w. and zhang, x.,“critical review in adsorption kinetic models”, j. zhejiang univ. sci. a, 10(5), 716-724, 2009. 13. foo, k.y. and hameed, b.h. “microwave-assisted preparation and adsorption performance of activated carbon from biodiesel industry solid reside: influence of operational parameters”, bioresource technology 103, 398– 404, 2012d. 14. al-johani, h., and salam, m. a. "kinetics and thermodynamic study of aniline adsorption by multiwalled carbon nanotubes from aqueous solution". journal of colloid and interface science, 360(2), 760–767,2011. 15. yu, y., zhuang, y.y. and wang, z.h.,"adsorption of water soluble dye onto functionlized resin". j. colloid interface sci. 242, 288-293, 2001. http://www.iasj.net/ available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol. 24 no.2 (june 2023) 1 – 10 eissn: 2618-0707, pissn: 1997-4884 *corresponding author: name: noor q. jaber, email: noorqasim97@gmail.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. emulsion liquid membrane for pesticides removal from aqueous solution: emulsion stability, extraction efficiency and mass transfer studies noor q. jaber a, b, *, ahmed a. mohammed b, and qazi nasir c a al-kawarizmi college of engineering, university of baghdad, baghdad, iraq b environmental engineering department, college of engineering, university of baghdad, baghdad, iraq c department of chemical and petrochemical engineering, college of engineering and architecture, university of nizwa, pc 616, pob 33 nizwa, sultanate of oman abstract the current study investigated the stability and the extraction efficiency of emulsion liquid membrane (elm) for abamectin pesticide removal from aqueous solution. the stability was investigated in terms of droplet emulsion size distribution and emulsion breakage percent. the proposed elm included a mixture of corn oil and kerosene (1:1) as a diluent, span 80 (sorbitan monooleate) as a surfactant and hydrochloric acid (hcl) as a stripping agent without utilizing a carrier agent. parameters such as homogenizer speed, surfactant concentration, emulsification time and internal to organic volume ratio (i/o) were evaluated. results show that the lower droplet size of 0.9 µm and higher stable emulsion in terms of breakage percent of 1.12 % were formed at 5800 rpm of homogenizer speed, 4 v% of span 80 surfactant, 8 min of emulsification time and 1:1 (i/o) ratio while 86.4% of abamectin pesticides were extracted under these conditions. extraction kinetics and mass transfer study were also accomplished. the outcome of this study can be extended to the removal of other type of pesticides from water and wastewater. keywords: emulsion liquid membrane, pesticides, stability, extraction. received on 08/10/2022, received in revised form on 25/10/2022, accepted on 05/11/2022, published on 30/06/2023 https://doi.org/10.31699/ijcpe.2023.2.1 1introduction pesticides are chemical compounds that are poor water solubility used for the control of pests. the constant population growth, changing lifestyle patterns, and technical improvement necessitate the usage of pesticides in significant quantities to meet the enormous demand for agricultural products in modern times. because their use has resulted in soil pollution, excessive amounts of residual pesticides are now considered emergent contaminants [1]. additionally, pesticides frequently leak from the location of their initial application into surrounding water bodies, causing secondary water contamination [2]. it is considered one of the main factors that cause death by self-poisoning. they are extremely poisonous and they spread quickly in the surroundings, creating chronic disease (world health organization) [3]. there are many traditional techniques used to sequestration of pesticides from wastewater such as, chemical oxidation [4], adsorption [5], revers osmoses membrane [6] and electrochemical process [7]. many of these methods pose clear disadvantages, such as high energy consumption, low removal efficiency, high operation and capital cost. membrane separation processes (msps) are energy-efficient and clean techniques for separating various types of liquids and gases, particularly in the chemical and petrochemical industries [8]. among the various msps, liquid membranes (lms) found much application in chemical engineering, chemistry, and environmental studies [9]. bulk liquid membrane, emulsion liquid membrane, and supported liquid membrane are the three most common types of liquid membranes [10]. recently, the emulsion liquid membrane has been given a considerable attention by a host of researchers for removing and recovering organic and inorganic contaminants from aqueous solutions due to its simplicity, high efficiency, easy operation, low operating cost, high flux and simultaneous extraction and stripping in one-step [11]. elm are double water-in-oil-in–water emulsions (w/o/w) stabilized by employment of suitable surface-active agents. this system consists of organic solution (membrane phase), stripping solution (internal phase) and dispersed phase (external phase) [12]. elms are true double emulsions, an internal aqueous phase being spread as small droplets into oil phase, while the resulting emulsion is spread as large droplets into the external aqueous phase [13]. in spite of the various benefits, the applicability of elm very restricted owing to several problems; one of them is emulsion instability. the term instability refers to breakage or swelling of an emulsion, which lowers the http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:noorqasim97@gmail.com http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2023.2.1 n. q. jaber et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 1 10 2 effectiveness of solute extraction and recovery [14, 15]. emulsion breakage occurs during extraction process or before this process. in the elm process, the resistance of liquid membrane for rupture during solute extraction under strong shear stress is known as emulsion stability. membrane rupture also occurs when the ph of the external phase rises, allowing the internal phase to spill out into external phase [16]. emulsion diameter is on of important factors affecting on emulsion stability [17]. emulsification process and membrane composition play an essential part in emulsion stability related with the droplet size of the emulsion. large diameter of droplet product the poor stability and low extraction efficiency [18, 19]. surfactant concentrations, emulsification time, internal to organic volume ratio and homogenizer speed, are the main factors affecting emulsion stability. a carrier agent is utilized in various liquid membrane technologies to assist the transfer of the target species, which imposing extra cost [20]. the conventional diluents used in emulsion liquid membrane systems are primarily made up of organic solvents derived from petroleum (diluents) kerosene [12, 21] hexane [22, 23], heptane [24, 25], which are flammable, volatile, toxic, and non-biodegradable. in addition, these materials could be extremely expensive due to restricted resources. to overcome these problems, replacement of the classical petroleum-based organic diluents with greener materials such as vegetable oil based organic diluents, which is easily obtainable and might include surface active compounds that can enhance emulsion stability [26]. to date, investigating the stability of elm employing a combination of kerosene and corn oil in the presence of span 80 as surfactant and using this membrane to remediation of abamectin pesticide from an aqueous solution has not been studied. therefore, the current research aims to investigate its impact of the surfactant concentration, emulsification speed, emulsification time, internal to membrane (i/o) phase ratio on the emulsion droplets and membrane stability. additionally, extraction efficiency of abamectin pesticides without using extractant (carrier agent) was studied. 2materials and methods 2.1. materials corn oil (density=0.92g/ml, molcular wieght= 882 g/mol) obtained from a local market and kerosene (density=0.81g/ml, molcular wieght=170 g/mol) supplied from iraq southren oil company were used as diluent and they are insoluble in water. span 80 and hydrochloric acid (hcl 35% purity) were used as the surfactant and the internal agent respectively. the external aqueous solution was produced by mixing distilled water with the abamectin pesticide. 2.2. preparing the water in oil (w/o) emulsion a high-speed homogenizer was used to prepare the emulsion in a 100 ml beaker flask. the liquid membrane phase was prepared by dissolving suitable amount of span 80 in the diluent (corn oil and kerosene). 0.25 m hcl solution acting as internal phase, was added drop by drop to oil phase and blended with a high-speed homogenizer at a specific emulsification time. the w/o emulsion droplet diameters were measured directly after formation using the olympus optical microscope (nikon eclipseme 600) equipped with a digital camera (dxm1200 f). sauter mean diameter d32 is calculated according to eq. 1 below [19]. d32 = ∑ ni idi 3 ∑ nii di 2 = 6 v a (1) where di and ni are the diameter and numbers of drops fitting to the ith class. v and a are the volume and total area of dispersed phase respectively. 2.3. stability study emulsion was added to 50 ppm abamectin aqueous solution. a mixer was used to agitate the system at 250 rpm during 15 minutes, then samples of the aqueous solution (external phase) were taken for measurement of abamectin concentration and ph. membrane breakage b (%) was calculated using eq. 2 below [27, 28]. b(%) = vi vio × 100% (2) where vio : initial volume of the internal phase and vi: volume of internal phase that dripped into feed phase, which is evaluable using eq. 3 below. vi = vf 10−phif −10−phf 10−phf −[hio + ] × 100 (3) where vf is a volume of initial feed phase, phifis a ph of initial feed phase, phfis the ph of feed phase after the mixing time, while [hio + ]: proton concentration in internal phase. 2.4. extraction study the extraction investigation was conducted by determining the removal efficiency of abamectin from feed phase by using eq. 4 below. e% = cin−cout cin × 100% (4) where cin: initial concentration of abamectin in external phase, and cout: the postextraction abamectin concentration in external phase. the concentration of abamectin in the solution was determined by a uv visible spectrophotometer at the wave length of 210 nm. fig. 1 represents the sequence of elm process. unless otherwise stated the experimental condition of the emulsion liquid membrane as given in table 1. n. q. jaber et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 1 10 3 fig. 1. sequence of elm process table 1. experimental condition for elm external phase ph 7 volume (ml) 250 abamectin concentration (ppm) 50 external to emulsion phases ratio (treat ratio) 5:1 organic solution volume (ml) 25 diluent 1:1 corn oil to kerosene span 80 (v%) 4 emulsification time (min) 8 homogenizer speed (rpm) 5800 extraction speed (rpm) 250 extraction time (min) 15 internal phase volume (ml) 25 [hcl] (m) 0.25 3results and discussion 3.1. effect of span 80 concentration surfactant is one of essential compound that is influence on stabilizing the emulsion as decrease the interfacial tension between oil and water phases. a surfactant was introduced to act as a barrier between the two miscible phases, thereby, inhibiting emulsion breaking. by changing the surfactant concentration at 2, 4, 6, and 8 (%v/v), the effect of surfactant concentration on droplet size, membrane rupture, and extraction efficiency was investigated. the results are plotted in fig. 2 and fig. 3 respectively, from fig. 2 it can be seen that at low surfactant concentration 2 (%v/v), the droplet diameters of (w/o) emulsion is 1.6 µm, that is lead to high interfacial tension of oil-water because of low concentration from surfactant, the membrane interface is not completely covered leading to the difficult dispersion of emulsion droplet and occur coalescence of small droplet lead to bigger emulsion droplets formed [29]. as the concentration increased to 4 (%v/v) the droplet diameter decreased from 1.6 µm to 0.9 µm and hence breakage percent from 3.17% to 1.12% and extraction efficiency of about 86.4% was achieved compared to 71.6% with 2 (%v/v) of surfactant concentration. that because of increasing the surfactant concentration gradually reduced membrane surface tension, resulting in larger contact area [30]. furthermore, increase in span 80 concentrations beyond 4 (%v/v) up to 8 (%v/v) led to increase droplet diameter and breakage percent from 0.9 µm to 1.36 µm and from 1.12% to 2.1% respectively. the explanation of this behavior is that the excess of surfactant adsorbed onto the surface of emulsion droplets, which led to droplets coalescence [31]. ahmad et al., [32] noticed same behavior. alternatively, abamectin extraction efficiency fallen from 86.4 % to 62% with an increase in surfactant concentration from 4 v% to 8 v%. this decrease could be attributed to the high mass transfer impedance of abamectin transport at the internal–oil contact. fig. 2. effect of span 80 concentration on emulsion diameter and membrane breakage (emulsification time= 8 min, i/o= 1:1, homogenizer speed= 5800 rpm, 0.25 m hcl) fig. 3. effect of surfactant concentration on extraction of abamectin (homogenizer speed= 5800 rpm, emulsification time= 8min, mixing speed of feed solution= 250 rpm, 0.25 m hcl internal phase, i/o= 1:1, ph=7) 3.2. effect of emulsification speed emulsification speed represents one of essential factors having a signification effects on droplets size, emulsion stability and so on the extraction efficiency. to investigate the impact of homogenizer speed to droplet size and emulsion breakage, homogenizer speed was examined in the range from 3000 rpm to 19700 rpm. fig. 4 shows that the sauter mean diameter (d32) and the breakage percent decreased from 2.3 µm to 0.9 µm and from 10% to 1.12% respectively as the homogenizer speed increased from 3000 to 5800 rpm. as internal phase droplets become smaller, it takes significantly longer time to coalesce, resulting in low breakage and hence good stability. the lack of homogeneity in the shape and size of the droplets in an emulsion might contribute to emulsion instability. low energy yields low disruptive forces, for breaking up (oil/water) phases mechanically into smaller drops thus inhibiting the stirring ability to disperse oil n. q. jaber et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 1 10 4 drops resulting in bigger emulsion drops [33]. using high stirring speeds produce fine droplets with a greater surface area, increasing the interfacial area of the feed solution and the emulsion liquid membrane and thereby increasing membrane stability. similar performance was also observed by kumbasar and tutkun [34]. further increase of homogenizing speed at 12700 rpm, the droplets diameter and breakage percentage increased to 1.13 µm and 3.5% respectively. this behavior could be attributed to the ostwaled ripening phenomena caused by coalescence, which results in an oiling – off process, which produces emulsion breakdown. furthermore, blending surfactant quickly may result in it separating from the water-oil interface [33]. fig. 5 shows an optical microscopy image of emulsion at various homogenizer speeds. the efficiency of extraction improved from 56.4% to 86.4% as the homogenizer speed increased from 3000 to 5800 rpm within 12 min contact time as shown in fig. 6. this is due to an increase in the mass transfer area which is enhanced the rate of mass transfer through extraction system. further increase in the homogenizer speed at 12700 rpm resulted decline in the extraction efficiency owing to the rupture of the membrane, because of the quick coalescence of droplets made the film layers unable to withstand the impact force, causing the emulsion breakage. suleiman et al., [35], observed similar behavior. at high homogenizing speed of 19700 rpm, a thick emulsion and emulsion is formed containing big emulsion droplet which reduces the emulsion stability. this might be because little drops agglomerate quickly, increasing their volume and forcing the emulsion to separate. as a result, since the emulsifier has a propensity to destabilize and break easily, high homogenizer speed is not necessary. fig. 4. effect of homogenizer speed on emulsion diameter and membrane breakage (span 80= 4 v%, emulsification time =8 min , 0.25m hcl, i/o =1:1) fig. 5. microscopic images of the emulsion at (1) 3000 rpm, (2) 5800 rpm, (3) 12700 rpm, (4) 19700 rpm (1) (2) (3) (4) n. q. jaber et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 1 10 5 fig. 6. effect of homogenizer speed on extraction of abamectin (emulsification time = 8 min, mixing speed of feed solution= 250 rpm, 0.25 m hcl internal phase, i/o= 1:1, ph=7, span80 = 4 v %) 3.3. effect of emulsification time the effect of different emulsification time range 4 to 12 minutes on the droplet emulsion diameter, breakage percent and extraction efficiency were investigated keeping other parameters constant. as presented in fig. 7 the lower sauter mean diameter of 0.9 µm and the lower breakage of 1.12% were obtained for an emulsification time of 8 min. for insufficient emulsification time 4 and 6 minutes, the droplet have a large size of 2.8 µm and 1.8 µm respectively and the breakage was great at 9.8% and 4.5 % for 4 and 6 minutes emulsification time respectively, this may be related to the lack of homogeneity which, resulted in droplet coalescence. caouchi and hamdaoui [36] and salahshoori et al., [37] observed a higher breakage of the emulsion with the lower emulsification time. in contrast, a further increase in emulsification time above 8 min led to increase the droplet emulsion diameter and hence reduce the emulsion stability. as shown in fig. 7 the emulsion droplets increase to 1.2 µm and 1.7 µm and so the breakage percent increased to 1.4% and 2.2% with increasing emulsification time to 10 and 12 minutes respectively. longer emulsifying time increases the shear stress and interfacial tension due to high homogenization pressure [38]. the effect of emulsification time on the extraction efficiency was investigated and the results are plotted in fig. 8. this figure shows that only 56 % abamectin removal efficiency from aqueous solution at 4 min was achieved, whereas the extraction efficiency rose up to 86.4% at 8 min emulsification time due to decrease in the droplet emulsion size and so increased the stability of the emulsion and this enhanced the homogeneity of the dispersed phase. a significant decreased in the extraction efficiency from 76.5 % to 63 % as the emulsification time increased from 10 min to 12 min particularly due to the coalescence of the internal phase droplets. on other hand, for the emulsification time less than 8 min, the extraction efficiency dropped to 65 % and 56 % at 6 min and 4 min emulsification time respectively. this reduction in the extraction efficiency, mainly due to the coalescence of the internal phase droplets. based on these results 8 min of emulsification time was considered for all experiments. fig. 7. effect of emulsification time on emulsion diameter and membrane breakage (span 80 = 4 v%, i/o= 1:1, 0.25m hcl, homogenizer speed =5800 rpm) fig. 8. effect of emulsification time on extraction of abamectin (homogenizer speed= 5800 rpm, span80 concentration = 4 v%, mixing speed of feed solution = 250 rpm, 0.25m hcl internal phase, i/o= 1:1, ph=7) 3.4. effect of internal to membrane phase ratio (i/o) volume ratio of internal aqueous phase to membrane phase has a significant effect on emulsion droplet diameter, breakage percent and hence on the extraction efficiency in the emulsion liquid membranes. the influence exerted by the ratio of the internal phase to the membrane phase on the sauter mean diameter, stability and extraction efficiency were studied at five different volume ratios (1:3, 1:2, 1:1, 2:1, 3:1). the results are presented in fig. 9 for emulsion droplet diameter and breakage percent, while the effect of internal to membrane phase volume ratio on the extraction of the abamectin is plotted in fig. 10. from fig. 9 it can be seen that the lower droplet diameter (0.9 µm) and higher emulsion stability in term of lower breakage percent (1.12 %) were obtained at equal ratio of the internal to membrane phases. decreasing the volume ratio of the internal to membrane phase from 1:2 to 1:3 led to increasing the droplet diameter and breakage percent from 1.5 µm to 1.8 µm and from 6% to 8% respectively. this behavior is due to too much membrane solution led to produce thicker and more viscous emulsion wall which obstructs the internal phase from diffusing in. similar trend was observed by mohammed et al., [25]. on other hand, a high volume ratio could not encapsulate the n. q. jaber et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 1 10 6 internal phase droplets, thus producing 1.3 µm and 2.1 µm droplet diameters at 2:1 and 3:1 volume ratio respectively and increasing the breakage percent to 5.3 % and 13 % respectively. therefore, this resulted in the formation of a thinner membrane layer that adversely impacted the membrane stability. from fig. 10 it can be seen that the maximum extraction efficiency was reached within phase ratio of 1:1. while the extraction efficiency dropped to 64 % and 51 % with decreasing the volume ratio to 1:2 and 1:3 respectively. this decrease in the extraction efficiency is due to less stripping agent available to re-extract the solute. conversely increasing the volume of the internal to membrane phase above 1:1 results in a noticeable decline in the extraction efficiency from 86.4 % at equal volume to 77.2 % and 60 % at volume ratio of 2:1 and 3:1 respectively. this may be due to an increase of the droplets diameter, which in turn decreases the interfacial contact area between the feed solution and the emulsion and thereby decreases the extraction efficiency. in addition, the volume of membrane solution is not enough for enclosing all the stripping solution at higher volume ratio [39]. the same trend was observed by daas and hamdaoui [40]. therefore, the value of 1/1 volume ratio of internal phase to membrane phase has been selected. fig. 9. effect of i/o phase ratio on emulsion diameter and membrane breakage (span 80 = 4 v%, 0.25m hcl, emulsification time =8min. homogenizer speed =5800 rpm) fig. 10. effect of i/o phase ratio on extraction of abamectin (homogenizer speed =5800 rpm, emulsification time= 8 min, mixing speed of feed solution =250 rpm, 0.25m hcl internal phase, ph=7, span 80 = 4 v %) 4estimation of the abamectin extraction kinetics and mass transfer coefficient abamectin kinetic extraction by elm process was estimated in eq. 5 as a first order rate [41, 42]. ln ( 𝐶𝑡=𝑡 𝐶𝑡=0 ) = −kobs. t (5) where kobs : extraction rate constant ( min −1), t: indicating the extraction time (min), the slope of the straight line formed by ln( 𝐶𝑡=𝑡 𝐶𝑡=0 ) and t, obtained on value of kobs = 0.236 (min −1). eq. 6 represents the overall mass transfer coefficient for the elm system [43]. 1 ko = 1 km + 1 kf (6) where ko : represents the elm overall mass transfer coefficient, km: represents mass transfer coefficient of external phase (m/s) was estimate by eq. 7 below [41]. km √nd = 2.932 × 10−7 . (vi+vm) (vi+vm+ve) . ( di dii )0.548 re1.371 (7) feed phase mixing speed is n, diameters of mixing tank and impeller respectively are dii, di , volumes of external, internal and membrane phases respectively are ve , vi , vm . re = n di 2ρe μe (8) re, was computed using eq. 8, and the result is (3666.29). d: solute diffusivity in the organic phase and calculated by eq. 9 below [44], which is found equal to 2.1× 10−11m2/s. d = 117.3 ×10−18 .(φ mw) 0.5 . t μ o. ∅c 0.6 (9) where mw: average diluent molecular weight (526 kg/ kmol), φ: diluent association factor (1). t: ambient temperature (298 k). μo: organic phase viscosity (0.0417 kg/m.s). ∅𝑐 : abamectin molar volume (0.862m 3/kmol), kf: interfacial reaction rate constant (m/s) estimated by using eq. 10 below. ln ( ct=t ct=0 ) = −a kf. t (10) on comparing eq. 10 with eq. 5, kf can be identified through eq. 11. kf = kobs a (11) where a: emulsion specific interfacial area, calculated using eq. 12 [45]. a = ai v = 6α d32 (12) n. q. jaber et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 1 10 7 the calculated values of kf, km and k𝑜 are tabulated in table 2 below. table 2. values of kf, kmand ko mass transfer coefficient (m/s) value km 1.15 × 10 −7 kf 3.54 × 10 −8 ko 2.71 × 10 −8 5conclusions in this work, the feasibility of using a mixture of green organic solvent (corn oil) and petroleum based organic solvent (kerosene) in the volume ratio 1:1 as diluent in emulsion liquid membrane for the removal of abamectin pesticides from wastewater was investigated. the effect of various parameters on droplet emulsion diameter, emulsion breakage and hence on the abamectin extraction has examined and results showed that increasing the homogenizer speed from 3000 rpm to 5800 rpm decreased the sauter mean diameter and the breakage percent from 2.3 µm to 0.9 µm and 10% to 1.12% respectively. while increasing the speed above this value resulted in an increase in the sauter mean diameter up to 1.13 µm and 1.9 µm and the breakage percent to 3.5% and 6.3% for 12700 rpm and 19700 rpm respectively. this has an adverse effect on abamectin extraction efficiency. the effect of emulsification time showed that with increasing time from 4 min to 8min, the emulsion stability increased as the sauter mean diameter and the emulsion breakage decreased from 2.8 µm to 0.9 µm and 9.8% to 1.12% respectively. increasing span 80 from 2 v% to 4 v% enhanced the emulsion stability and hence extraction efficiency. while concentration above 4 v% had adverse effect on extraction efficiency, mainly due to the increasing of viscosity of the membrane and lead to mass transfer resistance. the effect of internal to organic volume ratio showed that with increasing the ratio up to 1:1, the emulsion breakage and droplet diameter decreased and the extraction efficiency enhanced while further increased in this ratio, the stability of emulsion decreased and hence abamectin extraction efficiency decreased. finally, lower emulsion droplet diameter 0.9 µm and breakage percent of 1.12 % and higher extraction efficiency 86.4% from the aqueous solution in optimal operational condition, 5800 rpm homogenizer speed, 4 v% span 80 concentration, 8 min emulsification time and 1:1 internal to organic volume ratio. it can be calculated that emulsion liquid membrane using a mixture of green and petroleum based organic diluents could be a promising option for pesticides removal from aqueous solution. references [1] s.yavari, a. malakahmad, n.b. sapari, and s. yavari, "sorption-desorption mechanisms of imazapic and imazapyr herbicides on biochars produced from agricultural wastes", journal of environmental chemical engineering, 4(4), 39813989, 2016, https://doi.org/10.1016/j.jece.2016.09.003 [2] j.o. ighalo, a.a. adelodun, a.g. adeniyi, and c.a. igwegbe, "modelling the effect of sorbate –sorbent interphase on the adsorption of pesticideses and herbicides by historical data design", iranian journal of energy and environment, 11(4), 253-259, 2020, https://dx.doi.org/10.5829/ijee.2020.11.04.02 [3] a. belguet, s. dahamna, a. abdessemed, k. ouffroukh, and a. guendouz, "determination of abamectin pesticide residues in green pepper and courgette growing under greenhouse conditions (eastern of algeria –setif)", eurasian journal of biosciences, 13(2),1741–1745, 2019. [4] w. lu, w. chen, n. li, m. xu, and y. yao, "oxidative removal of 4-nitrophenol using activated carbon fiber and hydrogen peroxide to enhance reactivity of metallophthalocyanine", applied catalysis b: environmental,87(3–4),146–151,2009, https://doi.org/10.1016/j.apcatb.2008.08.024 [5] j.a. rodriguez-liebana, a. lopez-galindo, c. jiménez de cisneros, a. galves, m. rozalen, r. sanchez-espejo, e.caballero, and a. pena, "adsorption/desorption of fungicides in natural clays from southeastren spain", applied clay science, 132133, 402–411, 2016, https://doi.org/10.1016/j.clay.2016.07.006 [6] a. mukherjee, r. mehta, s. saha, a. bhattacharya, p. k. biswas,and r. k. kole, "removal of multiple pesticide residues from water by low-pressure thinfilm composite membrane", applied water science. 10,1–8, 2020, https://doi.org/10.1007/s13201-02001315-y [7] n. modirshahla, m.a. behnajady, and s. mohammadi-aghdam, "investigation of the effect of different electrodes and their connections on the removal efficiency of 4-nitrophenol from aqueous solution by electrocoagulation", journal of hazardous materials. 154 (1-3), 778–786, 2008, https://doi.org/10.1016/j.jhazmat.2007.10.120 [8] m.takht ravanchi, t. kaghazchi, and a.kargari, "application of membrane separation processes in petrochemical industry: a review", desalination, 235(1-3),199–244, 2009, https://doi.org/10.1016/j.desal.2007.10.042 [9] p. kaghazchi, t. jacob, , h.wang, w.chen, and t. e. madey," first-principles studies on adsorbateinduced faceting of re (11 2̄ 1)", physical review b condensed matter and materials physics, 79(13),1– 4, 2009, https://doi.org/10.1103/physrevb.79.132107 https://doi.org/10.1016/j.jece.2016.09.003 https://dx.doi.org/10.5829/ijee.2020.11.04.02 https://www.proquest.com/docview/2330956150?pq-origsite=gscholar&fromopenview=true https://www.proquest.com/docview/2330956150?pq-origsite=gscholar&fromopenview=true https://www.proquest.com/docview/2330956150?pq-origsite=gscholar&fromopenview=true https://www.proquest.com/docview/2330956150?pq-origsite=gscholar&fromopenview=true https://www.proquest.com/docview/2330956150?pq-origsite=gscholar&fromopenview=true https://www.proquest.com/docview/2330956150?pq-origsite=gscholar&fromopenview=true https://doi.org/10.1016/j.clay.2016.07.006 https://doi.org/10.1016/j.jhazmat.2007.10.120 https://doi.org/10.1016/j.desal.2007.10.042 n. q. jaber et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 1 10 8 [10] h. e. mahmoud, and a. a. al-hemiri, "minimization of toxic ions in wastewater using emulsion liquid membrane technique", iraqi journal of chemical and petroleum engineering, v.11, no.1, 1119, 2010. [11] a. a. mohammed, and r. w. al-khateeb, "application of emulsion liquid membrane using green surfactant for removing phenol from aqueous solution: extraction, stability and breakage studies", journal of ecological engineering, 23(1), 305–314, 2022, https://doi.org/10.12911/22998993/143970 [12] h. m.salman, and a. a. mohammed," removal of copper ions from aqueous solution using liquid surfactant membrane technique", iraqi journal of chemical and petroleum engineering, v.20 , no.3 ,31 – 37, 2019, https://doi.org/10.31699/ijcpe.2019.3.5 [13] k. anarakdim, g. gutiérrez, á.cambiella, o.senhadji-kebiche, and m.matos, "the effect of emulsifiers on the emulsion stability and extraction efficiency of cr(vi) using emulsion liquid membranes (elms) formulated with a green solvent", membranes. 10, 2020, https://doi.org/10.3390/membranes10040076 [14] a. l. ahmad, a. kusumastuti, c. j.c. derek, and b. ooi, "emulsion liquid membrane for heavy metal removal: an overview on emulsion stabilization and destabilization", chemical engineering journal, 171(3) 870–882, 2011, https://doi.org/10.1016/j.cej.2011.05.102 [15] r. m. pfeiffer, "leakage and swell in emulsion liquid membranes: experimental studies and corrected computational methods",colorado school of mines proquest dissertations publishing, 13884892, 2019. [16] m. a. hussein, a. a. mohammed, and m. a. atiya, "application of emulsion and pickering emulsion liquid membrane technique for wastewater treatment: an overview", environmental science and pollution research, (vol. 26, issue 36, pp. 36184–36204). springer, 2019, https://doi.org/10.1007/s11356-01906652-3 [17] y. wan, and x. zhang," swelling determination of w/o/w emulsion liquid membranes", journal of membrane science, 196185–201, 2002, https://doi.org/10.1016/s03767388(01)00554-3 [18] a. l. ahmad, , n. d. zaulkiflee, a. kusumastuti, and m. m. h. s buddin,"removal of acetaminophen from aqueous solution by emulsion liquid membrane: emulsion stability study", industrial and engineering chemistry research, 58(2), 713–719, 2019, https://doi.org/10.1021/acs.iecr.8b03562 [19] n. d. zaulkiflee, a. l. ahmad, j. sugumaran, and n. f. c. lah, "stability study of emulsion liquid membrane via emulsion size and membrane breakage on acetaminophen removal from aqueous solution using toa", acs omega, 5(37), 23892– 23897, 2020, https://doi.org/10.1021/acsomega.0c03142 [20] a. shokri, p. daraei, and s. zereshki, "water decolorization using waste cooking oil: an optimized green emulsion liquid membrane by rsm", journal of water process engineering, 33, 101021, 2020, https://doi.org/10.1016/j.jwpe.2019.101021 [21] n. s. majeed and m. a. mohammed, "phenol removal from aqueous solution using emulsion liquid membrane process: batch experimental studies" association of arab universities journal of engineering sciences, 24(3), 135-149, 2017. [22] l. bahloul, f.ismail, and m.e. h. samar, "extraction and de-extraction of cationic dye using an emulsified liquid membrane in an aqueous solution", energy procedia journal, 36, 1232-1240, 2013, https://doi.org/10.1016/j.egypro.2013.07.139 [23] m. a. mohammed, w. o. noori, and h. a. sabbar,"application of emulsion liquid membrane process for cationic dye extraction". iraqi journal of chemical and petroleum engineering, 21(3), 39– 44, 2020, https://doi.org/10.31699/ijcpe.2020.3.5 [24] m. mesli, and n. e. belkhouche, "emulsion ionic liquid membrane for recovery process of lead. comparative study of experimental and response surface design", chemical engineering research and design. 129,160–169, 2018, https://doi.org/10.1016/j.cherd.2017.11.011 [25] a. a. mohammed, m. a. atiya, and m. a. hussein, "simultaneous studies of emulsion stability and extraction capacity for the removal of tetracycline from aqueous solution by liquid surfactant membrane", chemical engineering research and design, 159,225–235, 2020, https://doi.org/10.1016/j.cherd.2020.04.023 [26] n. jusoh, n.f.m. noah, and n. othman, "double emulsion (water-in-oil-in-water) system in succinic acid extraction a stability study", chemical engineering transactions, 63-523–528, 2018, https://doi.org/10.3303/cet1863088 [27] r. sabry, a.hafez, m. khedr, and a. el-hassanin, "removal of lead by an emulsion liquid membrane: part i", desalination. 212, 165–175, 2007, https://doi.org/10.1016/j.desal.2006.11.006 [28] a. a. mohammed, h. m .selman, and g.abukhanafer, "liquid surfactant membrane for lead separation from aqueous solution: studies on emulsion stability and extraction efficiency".journal of environmental chemical engineering, 6,6923– 6930, 2018, https://doi.org/10.1016/j.jece.2018.10.021 [29] zaulkiflee, n. d., shah buddin, m. m. h., and ahmad, a. l. (2018). extraction of acetaminophen from aqueous solution by emulsion liquid membrane using taylor-couette column. international journal of engineering, 31(8), 14131420. https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/360 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/360 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/360 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/360 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/360 https://doi.org/10.3390/membranes10040076 https://doi.org/10.1016/j.cej.2011.05.102 https://www.proquest.com/openview/f9250cea478e77a0fcb6320d820d84c2/1?pq-origsite=gscholar&cbl=18750&diss=y https://www.proquest.com/openview/f9250cea478e77a0fcb6320d820d84c2/1?pq-origsite=gscholar&cbl=18750&diss=y https://www.proquest.com/openview/f9250cea478e77a0fcb6320d820d84c2/1?pq-origsite=gscholar&cbl=18750&diss=y https://www.proquest.com/openview/f9250cea478e77a0fcb6320d820d84c2/1?pq-origsite=gscholar&cbl=18750&diss=y https://www.proquest.com/openview/f9250cea478e77a0fcb6320d820d84c2/1?pq-origsite=gscholar&cbl=18750&diss=y https://doi.org/10.1007/s11356-019-06652-3 https://doi.org/10.1007/s11356-019-06652-3 https://doi.org/10.1016/s0376-7388(01)00554-3 https://doi.org/10.1016/s0376-7388(01)00554-3 https://doi.org/10.1021/acs.iecr.8b03562 https://jaaru.org/index.php/auisseng/article/view/59 https://jaaru.org/index.php/auisseng/article/view/59 https://jaaru.org/index.php/auisseng/article/view/59 https://jaaru.org/index.php/auisseng/article/view/59 https://jaaru.org/index.php/auisseng/article/view/59 https://doi.org/10.1016/j.egypro.2013.07.139 https://doi.org/10.1016/j.cherd.2017.11.011 https://doi.org/10.1016/j.cherd.2020.04.023 https://doi.org/10.3303/cet1863088 https://doi.org/10.1016/j.desal.2006.11.006 https://doi.org/10.1016/j.jece.2018.10.021 https://www.ije.ir/article_73262.html https://www.ije.ir/article_73262.html https://www.ije.ir/article_73262.html https://www.ije.ir/article_73262.html https://www.ije.ir/article_73262.html https://www.ije.ir/article_73262.html n. q. jaber et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 1 10 9 [30] h. r. mortaheb, m. h. amini, f. sadeghian, b. mokhtarani, and h. daneshyar, "study on a new surfactant for removal of phenol from wastewater by emulsion liquid membrane", journal of hazardous materials, 160-582-588, 2008, https://doi.org/10.1016/j.jhazmat.2008.03.095 [31] b. abismail, j.p. canselier, a.m. wihelm, h. delmas, and c.gourdon, "emulsification by ultrasound: drop size distribution and stability", ultrasonics sonochemistry, 6(1-2), 75 -83, 1999, https://doi.org/10.1016/s1350-4177(98)00027-3 [32] a. l. ahmad, a. kusumastuti, c. j. c.derek ,and b. s.ooi, "emulsion liquid membrane for cadmium removal: studies on emulsion diameter and stability", desalination, 287, 30–34, 2012, https://doi.org/10.1016/j.desal.2011.11.002 [33] m. b. rosly, n . jusoh, n. othman, h. a.rahman, r. n. r. sulaiman, and n. f. m. noah, "stability of emulsion liquid membrane using bifunctional diluent and blended nonionic surfactant for phenol removal", chemical engineering and processing process intensification, 148, 107790, 2020, https://doi.org/10.1016/j.cep.2019.107790 [34] r. a. kumbasar, and o.tutkun, "separation of cobalt and nickel from acidic leach solutions by emulsion liquid membranes using alamine 300 (toa) as a mobile carrier", desalination. 224, 201– 208, 2008, https://doi.org/10.1016/j.desal.2007.04.088 [35] r. n. r. suleiman, and n. othman, n.a.s. amin, "recovery of ionized nanosilver by emulsion liquid membrane process and parameters optimization using response surface methodology", desalination and water treatment, 57(8) 3339-3349, 2016, https://doi.org/10.1080/19443994.2014.985724 [36] s. chaouchi, and o. hamdaoui, "acetaminophen extraction by emulsion liquid membrane using aliquat 336 as extractant", separation and purification technology, 129 32– 40, 2014, https://doi.org/10.1016/j.seppur.2014.03.021 [37] i. salahshoori, a. seyfaee, a. babapoor, and i. cacciohi , "recovery of manganese ions from aqueous solutions with cyanex 272 using emulsion liquid membrane technique: a design experment study", journal of sustainable metallurgy,7(3), 1074– 1090, 2021, https://doi.org/10.1007/s40831-02100396-6 [38] z. y. ooi, n. othman, m. mohamed, and r. rashid, "removal performance of lignin compound from simulated pulping wastewater using emulsion liquid membrane process", international journal of global 2014, https://doi.org/10.1504/ijgw.2014.061021 [39] r. s. juang, and k. h. lin, "ultrasound assisted production of w/o emulsion in liquid surfactant membrane processes", colloids and surfaces a: physicochemical and engineering aspects, 238(13),43-49, 2004, https://doi.org/10.1016/j.colsurfa.2004.02.028 [40] a. daas, and o. hamdaoui ,"extraction of bisphenol afrom aqueous solutions by emulsion liquid membrane",journal of membrane science, 348(1-2), 360-368, 2010, https://doi.org/10.1016/j.jhazmat.2010.02.033 [41] m. raji, m. e. m. mekhzoum, d. rodrigue, a.qaiss el kacem,and r.bouhfid, "effect of silane functionalization on properties of polypropylene/clay nanocomposites",composites part b: engineering. 146,106–115, 2018, https://doi.org/10.1016/j.compositesb.2018.04.013 [42] h. p.kohli, s. gupta, and m.chakraborty, "stability and performance study of emulsion nanofluid membrane: a combined approach of adsorption and extraction of ethylparaben",colloids and surfaces a: physicochemical and engineering aspects,579, 123675, 2019, https://doi.org/10.1016/j.colsurfa.2019.123675 [43] h. kasaini, f. nakashio, and m. goto, "application of emulsion liquid membranes to recover cobalt ions from a dual component sulphate solution containing nickel ions", journal of membrane science, 146, 159–168 ,1998, https://doi.org/10.1016/s03767388(98)00105-7 [44] r. e. treybal, "mass – transfer operations, third ed., mcgraw hill book company", malaysia. isbn-007-065176-0, 1980. [45] v. karcher, f. perrechil, and a. bannwart, "interfacial energy during the emulsification of water-in-heavy crude oil emulsions", brazilian journal of chemical engineering,32, 127–137, 2015, https://doi.org/10.1590/01046632.20150321s00002696 https://doi.org/10.1016/s1350-4177(98)00027-3 https://doi.org/10.1016/j.cep.2019.107790 https://doi.org/10.1080/19443994.2014.985724 https://doi.org/10.1007/s40831-021-00396-6 https://doi.org/10.1007/s40831-021-00396-6 https://doi.org/10.1504/ijgw.2014.061021 https://doi.org/10.1016/j.colsurfa.2004.02.028 https://doi.org/10.1016/j.jhazmat.2010.02.033 https://doi.org/10.1016/j.compositesb.2018.04.013 https://d1wqtxts1xzle7.cloudfront.net/35832916/mass_-_transfer_operations_r._e._treybal-libre.pdf?1417761942=&response-content-disposition=inline%3b+filename%3dmass_transfer_operations_r_e_treybal.pdf&expires=1687981897&signature=byo-sflg~wehudoyppuwlmtutdc9skrbdst5zynrworja3qaz-xkwk4gutk7sxrlmfi9sbn2rgpfhrvwgsedvcj5exdvbbkd4vjadftowsn-4xlwlaqeuvo3sgqubzo0hksu~uti67fn5j4ghegpslqpzro02opdw0rpwboqqbwc09vahaeticllkdprzx8knwfwbyhvcsmyanmx65hc8cmsejcwu7xukj8piivf1h1ka6um60wouwcvae3nhn6rtlzwbziwbzb8bejdybcmxyfhiv6fw8yq3u1~zreb0uiyvgvclugspqss6bowxnv1wuqybyj4v4dnpb8z4o~29w__&key-pair-id=apkajlohf5ggslrbv4za https://d1wqtxts1xzle7.cloudfront.net/35832916/mass_-_transfer_operations_r._e._treybal-libre.pdf?1417761942=&response-content-disposition=inline%3b+filename%3dmass_transfer_operations_r_e_treybal.pdf&expires=1687981897&signature=byo-sflg~wehudoyppuwlmtutdc9skrbdst5zynrworja3qaz-xkwk4gutk7sxrlmfi9sbn2rgpfhrvwgsedvcj5exdvbbkd4vjadftowsn-4xlwlaqeuvo3sgqubzo0hksu~uti67fn5j4ghegpslqpzro02opdw0rpwboqqbwc09vahaeticllkdprzx8knwfwbyhvcsmyanmx65hc8cmsejcwu7xukj8piivf1h1ka6um60wouwcvae3nhn6rtlzwbziwbzb8bejdybcmxyfhiv6fw8yq3u1~zreb0uiyvgvclugspqss6bowxnv1wuqybyj4v4dnpb8z4o~29w__&key-pair-id=apkajlohf5ggslrbv4za https://d1wqtxts1xzle7.cloudfront.net/35832916/mass_-_transfer_operations_r._e._treybal-libre.pdf?1417761942=&response-content-disposition=inline%3b+filename%3dmass_transfer_operations_r_e_treybal.pdf&expires=1687981897&signature=byo-sflg~wehudoyppuwlmtutdc9skrbdst5zynrworja3qaz-xkwk4gutk7sxrlmfi9sbn2rgpfhrvwgsedvcj5exdvbbkd4vjadftowsn-4xlwlaqeuvo3sgqubzo0hksu~uti67fn5j4ghegpslqpzro02opdw0rpwboqqbwc09vahaeticllkdprzx8knwfwbyhvcsmyanmx65hc8cmsejcwu7xukj8piivf1h1ka6um60wouwcvae3nhn6rtlzwbziwbzb8bejdybcmxyfhiv6fw8yq3u1~zreb0uiyvgvclugspqss6bowxnv1wuqybyj4v4dnpb8z4o~29w__&key-pair-id=apkajlohf5ggslrbv4za https://doi.org/10.1590/0104-6632.20150321s00002696 https://doi.org/10.1590/0104-6632.20150321s00002696 n. q. jaber et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 1 10 10 ، كفاءة ثبات المستحلب: غشاء سائل مستحلب إلزالة المبيدات من المحلول المائي االستخالص ودراسات نقل الكتلة 3 غازي ناصرو ،2 أحمد عبد محمد ،، *2، 1 نور قاسم جابر العراق، بغداد، جامعة بغداد، كلية الهندسة الخوارزمي، قسم الهندسة الكيميائية االحيائية 1 العراق، بغداد، جامعة بغداد، كلية الهندسة، قسم الهندسة البيئية 2 سلطنة عمان ،جامعة نزوى ،ندسة الكيمياوية والبتروكيمياويةقسم اله 3 الخالصة استقرار وكفاءة استخالص الغشاء السائل المستحلب إلزالة مبيد أبامكتين من بحثت الدراسة الحالية في تضمن. تم فحص الثبات من حيث توزيع حجم مستحلب القطيرات ونسبة تكسر المستحلب. المحلول المائي elm كمادة مخففة( 1: 1)المقترح خليًطا من زيت الذرة والكيروسين ،span 80 كمادة خافضة للتوتر تم تقييم معامالت مثل سرعة المجانسة . السطحي وحمض الهيدروكلوريك كعامل نزع دون استخدام عامل ناقل أظهرت النتائج أن حجم .(i / o) وتركيز الفاعل بالسطح ووقت االستحالب ونسبة الحجم الداخلي إلى العضوي 5800٪ تشكلت عند 1.12لكسر ميكرومتر والمستحلب المستقر األعلى من حيث نسبة ا 0.9القطرة األدنى : 1دقائق من وقت االستحالب و 8، و السطحي 80فولت من االمتداد 4، و دورة في الدقيقة من سرعة الخلط 1 (i / o) كما تم إنجاز حركيات . ٪ من مبيدات األبامكتين تحت هذه الظروف86.4بينما تم استخالص نتائج هذه الدراسة إلى إزالة أنواع أخرى من المبيدات من المياه يمكن أن تمتد . االستخراج ودراسة النقل الجماعي .ومياه الصرف الصحي .ِاسِتخالص ،استقرار ،مبيدات حشرية ،مستحلب سائل غشاء :الكلمات الدالة iraqi journal of chemical and petroleum engineering vol.16 no.1 (march 2015) 91105 issn: 1997-4884 biosorption of lead, cadmium, and zinc onto sunflower shell: equilibrium, kinetic, and thermodynamic studies ahmed a. mohammed environmental engineering department, college of engineering, baghdad university, iraq. abstract the present study deals with the application of an a bundant low cost biosorbent sunflower shell for metal ions removal. lead, cadmium and zinc were chosen as model sorbates. the influences of initial ph, sorbent dosage, contact time, temperature and initial metal ions concentration on the removal efficiency were examined. the single ion equilibrium sorption data were fitted to the non-competitive langmuir and freundlich isotherm models. the freundlich model represents the equilibrium data better than the langmuir model. in single, binary and ternary component systems,pb +2 ions was the most favorable component rather than cd +2 and zn +2 ions. the biosorption kinetics for the three metal ions followed the pseudosecond order kinetics indicating that the chemical sorption was the rate-limiting step. the thermodynamic parameters including free energy ( g 0 ), enthalpy and entropy changes for pb 2+ ,cd 2+ and zn 2+ ions indicated that the sorption process was feasible,spontaneous,and endothermic in the temperature range 20-50 0 c .desorption of the three metals ions from the biosorbent was effectively achieved in a 0.2 mol l -1 hcl solution. key words: biosorption, heavy metals, kinetics, isotherm, thermodynamics, sunflower introduction the use of heavy metals over the past few decades has been tremendously increased due to rapid industrialization in both developed and developing nations, which results an increased flux of metallic substances in the aquatic environment , [1]. among various organic and inorganic pollutants, heavy metal ions are very toxic and carcinogenic in nature , [3]. heavy metals enter into the food chain through the disposal of wastes into water bodies. according to the world health organization, the heavy metals of concern are lead, cadmium, chromium, zinc, copper, mercury, etc [4]. these metals are often derived from industries such as electroplating and battery factories, petrochemical refining, metal finishing, chemical manufacturing , [5]. therefore, it is necessary to treat heavy metals effluents properly before they are discharged into the water bodies. in the present work, lead, cadmium, and zinc have been chosen as the contaminant in aqueous medium. several technologies are available to remove heavy metals from wastewater before it can be iraqi journal of chemical and petroleum engineering university of baghdad college of engineering biosorption of lead, cadmium, and zinc onto sunflower shell: equilibrium, kinetic, and thermodynamic studies 92 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net launched into water bodies, such as: coagulation, flocculation, flotation, membrane separation, ionic, exchange resins and biological treatments, [6]. however, these methods are expensive, require sensitive operating conditions and produces huge quantity of sludge , [7]. therefore , more economic,practical and efficient techniques are needed to meet the requirments of recovery and/or removal of metal ions. biosorption of metal ions from aqueous solutions is a relatively new technology for wastewater treatment. biosorption has been defined as the property of certain biomolecules to bind and concentrate selected ions or other molecules from aqueous solution. as opposed to a much more complex phenomenon of bioaccumulation based on active metabolic transport, biosorption by dead biomass is passive and based mainly on the affinity between the biosorbent and sorbate , [8] [9]. biosorbents come under the following categories bacteria, fungi, algae, industrial wastes, agricultural wastes and other polysaccharide materials. among them, agricultural wastes are the potential sources for producing biosorbents as they have no prominent utilization. agricultural wastes are usually composed of lignin and cellulose as major constituents and may also include alcohols, aldehydes, ketones, carboxylic, phenolic and other groups, [10]. a number of studies have been focused on agricultural wastes that are capable of removing metals from wastewater such as apple wastes , [11], tea waste and coffee , [12], corn corps , [13], orange peel , [14], rice husk , [15], rice straw [16], wood apple shell , [1], coconut , [17], maize husk , [18] etc. since industrial effluents may contain several matels , its necessary to study the simultaneous sorption of two or more metal ions and also to quantify the interactive effect of one metal ion on the other. little information is available in literature for the simultaneous removal of cadmium, lead and zinc ions using sunflower shell. therefore, the present work amis. to study the feasibility of using sunflower shell as an adsorbent for the removal of cd +2 , pb +2 , and zn +2 ions from aqueous solutions. the main objectives of this work are: i) to study batch biosorption process in single, binary, and ternary systems, ii) to study the influence of initial ph solution, contact time, initial metal concentrations, and biosorbent dosage on the removal efficiency, iii) to investigate the isotherm model that can describe the biosorption process, iv) to study the thermodynamic and kinetics of metals biosorption to understand the mechanism of biosorption onto sunflower. materials and methods biosorbent and sorbate preparation to remove dirt and impurities, the sunflower shell was washed with tap water then distilled water, dried at 100 °c for 2 days in the oven to remove the moisture content. the dried sunflower shell was milled and sieved, and the average particle size of 0.5-0.6 mm of powdered sunflower shell was selected for biosorption experiments. the following are the major physical properties of sunflower shell: surface area (8.2 m 2 /g), apparent density (0.98 g/cm 3 ), porosity (88.5 %), and moisture content (2.83 %).the stock solution (1000 mg/l) of each pb +2 , cd +2 , and zn +2 ions were prepared by dissolving appropriate amount of each metal salt in distilled water and then stored in glass containers at room temperature. the three metal salts were obtained from fluka company. the ahmed a. mohammed -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 93 desired concentrations were prepared by diluting the stock solution in accurate proportions to different initial concentrations. the concentration of the metal was subsequently determined by using flame atomic absorption spectrophotometer (aas), type: shimadzu, model: 7200,japan, the initial ph of the working solutions was adjusted to the required value by adding 1 mol/l naoh or hno3 using a ph meter (wtw, inolab 720, germany). to prevent heavy metal precipitation, some drops of hno3 was added to the collected samples. prior testing in aas, all the samples were refrigerated at approximately 40 o c. experimental work the effects of ph, biosorbent dose, agitation speed, and initial metal ion concentration on the removal efficiency of each metal were studied using classical approaches. in general, several stoppered conical flasks of 250 ml volume, each containing 0.5 g of biosorbent(except for dose effect) with 100 ml of 40 mg/l of each metal solution, were used. the suspension was shaken at 250 rpm for 2 h and temperature of 30 °c using an incubator shaker and the residual amount of metal was determined after filtration using aas. for the ph effect, the ph of the solutions was adjusted to 3, 4, 5, 6, and 7. solutions with ph above 7 were excluded owing to the precipitation of metals as hydroxide may occur. the effect of biosorbent dose was studied in the range of 0.2 to 2 g. different initial metal concentrations includ 10, 20, 40, 60 and 80 mg/l were used to study the effect of metal concentration . for the effect of contact time , the system was subjected to an agitation speed of 250 rpm, and the samples were collected from 1 to 360 min to be test for their metal remaining. isotherm experiments biosorption of each metal onto sunflower shell was investigated in single, binary, and ternary systems. for single system, the experiments were carried out in 250 ml stoppered conical flasks containing 100 ml of predetermined metal aqueous solution (10, 20, 30,40, 50, 60, 70, and 80 mg/l) and 0.5 g of sunflower shell, under constant shaking at 30±3 °c. the ph solution was adjusted to the best value based on the ph study. for each metal, eight flasks were placed in a shaker (edmund buhler, 7400 tubingen shaker-sm 25, germany) at constant shaking speed (250 rpm) for 2 h. upon equilibrium, the sorbent was separated from aqueous solution by using filter paper (whatman, no.42, diameter 7 cm). the residual concentrations of metal were measured by aas. the biosorption capacity at equilibrium conditions (qe) was calculated by using the following equation: ( ) ( ) where qe is the equilibrium biosorption capacity (mg/g), co and ce are the initial and equilibrium sorbate concentrations in water (mg/l), respectively, v is the volume of the sample solution (l), and m is the mass of the used adsorbent (g). the percentage of removal (%) was calculated by using the following equation: % removal= ( ) ( ) for binary and ternary systems, the same procedure of single system experimentation was followed, in which the mixture of equal amount of metal solution (40 mg/l) was subjected to biosorption process by using 0.5g of sunflower shell. biosorption of lead, cadmium, and zinc onto sunflower shell: equilibrium, kinetic, and thermodynamic studies 94 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net kinetic and thermodynamic experiments for kinetic experiments 40 mg/l concentration of pb +2 , cd +2 and zn +2 ion solutions were used. the sorption time varied between 0 and 180 min. in the isotherm experiments 0.5 g of biosorbent was added in 100 ml of pb +2, cd +2 and zn +2 ions solution. samples of 4 ml were withdrawn and filtrated then the supernatant solutions were analyzed for the residual metal ion concentration by using aas. the thermodynamic experiment was conducted using four flasks each flask containing 100 ml of 40 mg/l metal concentration, and the solution temperatures were 20, 30, 40, and 50°c (250 rpm for 2 h, at an optimum ph determined in the ph study). all determinations of each experiment were performed in triplicate and the average was used for this work. methods isotherm model in this study, the experimental isotherm data were fitted with the two well-known sorption isotherm models, namely, langmuir and freundlich models. these two models are presented in table (1). the langmuir model is the simplest model for monolayer sorption onto a surface and assumes that all of the sorption sites have equal adsorbate affinity, [19]. the freundlich isotherm model is used for homogenous systems in which the heat of sorption decreases in magnitude with an increasing extent of sorption , [20]. the freundlich isotherm model describes the ratio of the amount of solute that is adsorbed onto a given mass of adsorbent to the concentration of solute in the solution. kinetic and thermodynamic model the dynamics of the sorption process in terms of the order and the rate can be evaluated using the kinetic sorption data. a number of kinetic models have been used to describe the adsorption rate in batch operation. these models are pseudo-first order, pseudo-second order, and intraparticle diffution models as given in table (1). the pseudo-first-order kinetic model has been widely used to predict metal biosorption kinetics. the pseudo-firstorder rate expression suggested originally by lagergren is based on the solid capacity. the pseudo-secondorder kinetic model is based on the assumption that the rate of sorption follows second-order chemisorptions , [21]. this model assumes that the metal molecule is sorbed onto two sorption sites on the sunflower peels surface. the possibility of intraparticle diffusion of sorbate onto the adsorbent by using the intra-particle diffusion model were studied. an intra-particle diffusion rate can be expressed in terms of the square root time. the mathematical dependence of qt vs. t 0.5 is obtained if the sorption process is considered to be influenced by diffusion in the spherical particles and the convective diffusion in the solution. in addition, the thermodynamics parameters of the sorption process such as enthalpy changes (∆h°), entropy changes (∆s°), and gibbs free energy changes (∆g°) were used to determine the spontaneity of biosorption process. these parameters have been determined using van't hoff and gibbs free energy equations, table (1). ahmed a. mohammed -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 95 table (1), equations for the sorption isotherm and kinetics models model equation linear expression reference langmuir [22] freundlich [23] pseudo-first-order ( ) ( ) [24] pseudo-second-order [21] intraparticle diffusion same the original eq. [ 25] van't hoff [26] gibbs free energy [26] where is the sorption uptake (mg/g); is the equilibrium concentration of the sorbate (mg/l); is the maximum amount of the sorbate per unit weight of the sorbent (mg/g); is the langmuir constant and related to the free energy of sorption (l/mg); n is the freundlich constant related to sorption intensity (g/l); kf is the freundlich constant related to the relative sorption capacity (mg/g); is the metal uptake capacity (mg/g) at any time t; k1 is the observed rate constant of pseudo-first-order kinetic model (1/min); and k2is the observed rate constant of pseudo-second-order kinetic model (g/mg.min), kp(mg/g min 1/2 ) is the rate constant of intraparticle diffusion, c is the value of intercept which gives an idea about the boundary layer thickness ,kc is the equilibrium constant (qe/ce), r is the universal gas constant (8.314 j/mol. k), ∆h° is the enthalpy of the sorption (kj/mol), ∆s° is the entropy of the sorption (j/k.mol), is the gibbs free energy of biosorption (kj/mol), and t is the solution temperature (k). results and discussion several previously reported studies indicated that ph of solution is the most important parameter effecting the biosorption capacity due to the variation in the ph value leading to differences in the surface properties of the sorbent and degree of ionization , [27]. the removal efficiency of pb +2 , cd +2 , and zn +2 with ph ranging from 3 to 7 are studied and the results are depicted in fig.(1a). from this figure, it can be seen that the best ph value for three metal removals was around 5. at lower ph, the active surface sites of the sunflower were either positively charged , [14], resulting the protons to compete with the metal ions, or dissociated, [28], which resultes in a decrease in the metal removal efficiency. at a ph range from 5 to 7, the removal percentage decreased because some active groups on the sunflower shell surface may be less protonated according to the fact of zeta potential, [29]. a similar trend was reported for the biosorption of cd(ii), and cr(iii) removal using garden grass, [30]. biosorption of lead, cadmium, and zinc onto sunflower shell: equilibrium, kinetic, and thermodynamic studies 96 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net effect of biosorbent dosage the sorbent amount is also an important parameter to obtain the quantitive uptake of metal ions. fig. (1b) shows the results of experiments that measured the effect of sunflower dosages on the removal percentage of metals. it can be seen for three metals, that the removal percent increased with increasing the amount of sorbent from (0.2-0.9 g) and then relatively remain constant. the removal efficiencies increases steadily with an increase in the sorbent concentration beyond 5 g/l. however the increase in sorbent dosage generally increases the amount of solute sorbed, due to the increased surface area of the sorbent, which in turn increases the number of binding sites, [31]. in actual applications, the optimal sorbent dosage should be defined as the lowest concentration that gives reasonable metal removal efficiencies and in present work the optimal dosage was about 0.5 g /100 ml for the three metals. effect of contact time fig. (1c) shows the effect of contact time on the removal efficiency of each metal. from this figure it can be seen that the pb +2 , cd +2 , and zn +2 biosorption efficiency increased quickly within the first 60 min. the equilibrium condition was approximately attained within the first two hours contact time and then a relatively slow phase was observed beyond this time period. a further increase in contact time after 120 min had negligible effect on the removal efficiency. according to these results, the contact time was fixed at 120 min for the remaining of the batch experiments to make sure that the equilibrium was achieved. the rate of metal removal is higher in the beginning due to a larger surface area of the biosorbent being available for the biosorption of the metals. after that the competitive among three metals ions on the available active sites has been intensive by these ions , [18]. effect of initial metal concentration the initial concentration of pb +2 , cd +2 , and zn +2 ions provides an important driving force to outweigh all mass transfer resistance of the metal between the aqueous and solid phases. removal of these ions by 0.5 g sunflower shell dosage was investigated by employing the metal ions solutions with initial concentrations in the range of 10-80 mg/l at 120 min contact time and ph 5 , the results are depicted in fig.(1d). from this figure, it can be seen that the percentage removal of pb +2 decreased from 85.5 – 68.25%, for cd +2 79.5 – 61.3% and for zn +2 from 72.3 – 60% with increasing the initial metal ions concentrations from 10-80 mg/l. according to, [32], at lower metal ions concentration, the removal is higher due to larger surface area of sorbent available for sorption. when the concentration of metal ions is high, the percentage removal decrease since the available sites for sorption becomes less due to saturation of sorption sites. the same results were noticed by., [33]. kinetic study for any practical applications, the process design, operation control, and sorption kinetics are very important. information on the kinetics of metals uptake is required for selecting optimum operating conditions for fullscale batch processes. in addition, the sorption kinetics in wastewater treatment is significant, as it provides valuable insights into the reaction pathways and the mechanism of sorption reaction [21]. ahmed a. mohammed -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 97 fig. 1, effect of: a) ph; b) biosorbent dose; c) contact time, and d) initial metal concentration on the removal efficiency fig. (2a) shows the evolution of uptake during pb +2 , cd +2 , and zn +2 biosorption onto sunflower shell. in order to evaluate the kinetic mechanism that controls the biosorption process, pseudo first-order and pseudo second-order models were tested to interpret the experimental data that are presented in fig. (2a). the k1 and qe values for the pseudo-firstorder kinetic model were obtained from the slope and intercept of the linear plots of ln(qe-qt) verses t (fig. 2b), respectively, and the results are listed in table (2). although a straight line with high correlation coefficients was obtained for the first order kinetic model,there is a deviation between experimentally observed biosorption capacity and that derived from this model. this suggest that for each metal the biosorption did not likely to explain by pseudo-first-order kinetic model. the second-order-kinetic model is based on the assumption that the sorption follows second-order chemisorption, [21]. the parameters of pseudo-second-order kinetics (k2 and qe) were calculated from the linear plots of t/qt verses t (table (2)). the linear expression of this model is presented in fig. (2c). a straight line with high correlation coefficients was obtained for the second-order-kinetic biosorption of lead, cadmium, and zinc onto sunflower shell: equilibrium, kinetic, and thermodynamic studies 98 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net model much higher than the correlation coefficients derived from pseudo-first-order model fitting, also the deviation between the experimental and calculated biosorption capacity is less than that for pseudo-first order kinetic model. these results suggeste that the sorption process followes successfully pseudo-second-order kinetic model and the biosorption of pb +2 , cd +2 , and zn +2 onto sunflower shell surface is most likely to involve chemical interactions leading to binding of the ions to the surface by bonding as strong as covalent binding , [34]. similar phenomenon has been observed in the biosorpption of pb +2 , cd +2 , and ni +2 on the modified orange peel , [7]. according to the intraparticle diffusion model, the plot of qt vs. t 0.5 should be a straight line if this model is involved in the sorption process and if the plot passes through the origin then intraparticle diffusion is the sole ratelimiting step , [35]. fig (4d) shows the intraparticle diffusion plot for pb +2 , cd +2 , and zn +2 biosorption onto sunflower shell. it can be seen that this plot is multilinear, this suggests that the biosorption process is occurred in three phases ,., [36], [37]. the initial steeper section represents surface or film diffusion, the second linear section represents a gradual biosorption stage where intraparticle or pore diffusion is rate-limiting and the third section is the final equilibrium stage. when the straight line plot of intraparticle diffusion does not pass through the origin as shown in fig (2.d), it indicates that this process is not the only rate-limiting step and other kinetic processes may also control the rate of sorption , [38]. thus, there were three processes controlling the sorption rate but only one was ratelimiting in any particular time range. the parameters of the intraparticle diffusion model kp and c were calculated from the slope and intercept of the second linear section in fig (2d), respectively, and the results are presented in table (2). for the three metals, the law value of kp (<1 mg/g.min 0.5 ) in the second section indicates a slower transfer rate. the high positive value of the intercept c provides information related to the thickness of the boundary layer , [39]. larger intercept values indicate high boundary layer effect on the rate of sorption. biosorption process 1. single system sorption isotherm describes how sorbate molecule or ions are distributed between the solid phase and the liquid phase. equilibrium isotherms are measured to determine the capacity of the sorbent for metal ions. this was obtained by the measurement of the equilibrium uptake for each metal at an initial concentration range from 10 to 80 mg/l. fig. (3a) shows the typical equilibrium sorption of pb +2 , cd +2 , and zn 2+ ions on sunflower shell at 30 °c (single system). the biosorption capacity increased with the increase in the initial concentration of metals from 10 to 50 mg/l, and subsequently reached a plateau. a static biosorption capacity of 41.5, 37.1, and 33.8 mg/g of the sunflower sorbent was obtained for pb 2+ , cd 2+ and zn 2+ ions, respectively. pb +2 demonstrated higher biosorption capacity, when compared with other metals, which can be attributed to high electronegativity of this metal. these results are in agreement with those reported by [40], who noted that more electronegative metal ions will be more strongly attracted to the surface of the adsorbent. ahmed a. mohammed -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 99 fig. 2. results of kinetic study of three metals biosorption onto sunflower shell a) uptake; b) pseudo first order; c) pseudo second, and d) intrapartical diffution model table (2), kinetic parameters of pb +2 , cd +2 , and zn +2 biosorption onto sunflower shell metal qeq (exp) (mg/g) pseudo-first-order model pseudo-second-order model intraparticle diffusion model k1 (1/min) qeq (cal.) (mg/g) r 2 k2 (g/mg.min) qeq (cal.) (mg/g) r 2 kp mg/g.min 0.5 c r 2 pb +2 6.34 0.028 5.81 0.982 0.009 6.729 0.997 0.208 3.05 0.999 cd +2 6.00 0.0318 5.58 0.992 0.009 6.349 0.998 0.161 2.9 0.998 zn +2 5.16 0.033 4.697 0.996 0.010 5.540 0.997 0.058 2.64 0.998 biosorption of lead, cadmium, and zinc onto sunflower shell: equilibrium, kinetic, and thermodynamic studies 100 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net fig.3, biosorption isotherm: a) single system, b) pb +2 , c) cd +2 , and d) zn +2 in binary and ternary systems to find out the suitable isotherm models, analysis of isotherm data by adapting to different isotherm models is an important step that can be used for design purposes. in this study, the experimental equilibrium data were correlated to langmuir and freundlich isotherm models. the linearized form of these two models is presented in table (1). a plot of (ce/qe) vs. ce yielded a straight line. the slope and the intercept of this line then yielded the values of the langmuir constants qm and kl, respectively. the freundlich coefficients could be determined from the plot of lnqe verses lnce. table (3) shows the langmuir and freundlich model constants with the r 2 values. this table indicates that the freundlich model provides the best fit as judged by its correlation coefficient for the three metals. hence, the metals bind onto the heterogeneous surface of sunflower shell. 2. binary and ternary systems sorption behaviors of metal ions in binary and ternary systems have been studied using the initial concentrations (10, 20, 30,40, 50,60,70, 80 mg/l) for each metal ion and the results are presented in fig. (3 b-d). the sorption ahmed a. mohammed -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 101 capacity for pb +2 is greater than cd +2 and zn +2 in single, binary and ternary systems. as well as the biosorption of zn +2 was the lowest one when compared with the biosorption of other metals in all systems. this behavior may be attributed to several reasons from which the hydrated ionic radius as well as the electronegativity of pb +2 is higher than cd +2 , and zn +2 ions , [41]. the ions with hydrated radius smaller than the pore size are able to move easily within the pores. the hydrated ionic radius is as follows pb 2+ (401 pm), cd +2 (426 pm), zn +2 (430pm). the decrease of sorption capacity in binary and ternary systems compared to the single metal systems observed for all metals reflects the existence of a competition between the metals for the binding sites present in the sorbent. it seems that the total metal sorption capacity decreases when increasing the number of metals present. thermodynamic study desorption is a very important concern to allow for reusing the adsorbent and reduce process costs. it is desired that the adsorbent should be close to its original form, and should not lost its sorption ability after desorption, [32]. experiments were carried out to desorb the metal ions (pb 2+ , cd 2+ and zn 2+ ) from the metal loaded sunflower shell as a function of hcl concentration (mol/l).volume of 100 ml with 40 mg/l metal concentration was agitated with 0.5 g sorbent. after the filtration procedure the metal ions loaded sorbent was dried in air. then, treated with 50 ml of various concentrations of hcl to desorb the metal ions for 1 hour, the results are plotted in fig. (4b). as can be seen from this figure, the desorption efficiency increased with increasing hcl concentration up to 0.2 mol/l. however, the desorption efficiencies were relatively insensitive to further increase in hcl concentration. also, it can be seen that the metal which has the maximum biosorption uptake has the minimum recovery percent. table (3), parameters of single solute isotherm for pb 2+ , cd 2+ and zn 2+ ions onto sunflower shell model parameter s pb 2+ cd +2 zn +2 freundlic h k, (mg/g) 1.16 6 1.02 1.20 3 n 1.57 7 1.298 1.46 3 r 2 0.99 5 0.985 0.99 3 langmuir qm (mg/g) 16.0 1 15.92 15.1 1 b (l/mg) 0.06 2 0.051 0.03 9 r 2 0.92 9 0.937 4 0.91 8 table (4), the thermodynamic parameters for the biosorption of pb (ii), cd (ii), and zn (ii) ions on sunflower shell metal ∆h (j/mol) ∆s (j/mol.k) r 2 ∆g (j/mol) 293 k 303 k 313 k 323 k lead 18730 71.698 0.99 3 2238.68 3113.65 3814.94 4353.06 cadmium 13924.28 53.531 0.98 9 1624.8 2537.28 2927.56 3243.99 zinc 13968.35 51.343 0.99 1 1152.22 1503.92 2204.13 2602.17 biosorption of lead, cadmium, and zinc onto sunflower shell: equilibrium, kinetic, and thermodynamic studies 102 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net fig. 4, a) variation of percentage removal with temperature, b) effect of hcl concentration on the desorption efficiencies conclusions this study confirmed that sunflower shell is a promising biosorbent for lead, cadmium, and zinc removal from aqueous solutions. the biosorption equilibriums reached at 120 min contact time. the maximum biosorption capacity of 41.5, 37.1, and 33.8 mg/g on the sunflower sorbent was obtained at ph 5 for pb 2+ , cd 2+ and zn 2+ ions, respectively. the freundlich isotherm model provides the best fit for the experimental isotherm data of the three metals. in the binary and ternary systems, pb +2 demonstrated the highest biosorption capacity while zn +2 was the lowest one owing to the competition condition. the pseudo-second-order kinetic model better explained the biosorption dynamics process for the three metals than the pseudo-first-order kinetic model. . also the sorption process of pb 2+ , cd 2+ and zn 2+ ions are spontaneous and endothermic in nature. the biosorbed pb 2+ , cd 2+ and zn 2+ ions onto sunflower shell can be recovered using 0.2 mol/l hcl. good efficiency to remove toxic metal ions was achieved by the usage of this agricultural by product. references 1. doke k.m., yusufi m., joseph r.d., khan e.m., (2012), biosorption of hexavalent chromium onto wood apple shell: equilibrium, kinetic and thermodynamic studies. desalination and water treatment.vol. 50, pp. 170-179. 2. gupta v.k, ali i. (2004), removal of lead and chromium from wastewater using bagasse fly ash— a sugar industry waste. j colloid interface sci. vol. 271, pp.321– 328. 3. volesky b, may h, holan z.r. (2004), cadmium biosorption by saccharomyces cerevisiae, biotechnol bioeng ,vol.41, pp. 826–829. 4. who,(1984) world health organization. guidelines for drinking water quality, recommendations, 1st ed., vol. 1. geneva. 5. apiratikul r., marhaba t., wattanachira s., pavasant ahmed a. mohammed -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 103 p.,(2004), biosorption of binary mixtures of heavy metals by green macro algae: caulerpa lentillifera, j. sci. tech. vol. 26, pp.199-207. 6. caroline b., meuris g., eric g., (2014), chromium biosorption using the residue of alginate extraction from sargassum filipendula, chem. eng. j. vol., 237 , pp. 362-371. 7. feng, n., guo, x., liang, s., zhu, y., and liu, j., (2011), " biosorption of heavy metals from aqueous solutions by chemically modified orange peel", journal of hazardous materials, vol. 185, pp. 49-54. 8. volesky b., (2007), biosorption and me. water research. 41, 40174029. 9. diniz v., weber m.e., volesky b., naja g.,(2008), column biosorption of lanthanum and europium by sargassum, j. water research.vol. 47 , pp. 363-371. 10. hossain m.a., ngo h.h., guo w.s., setiadi t.,( 2012), adsorption and desorption of copper(ii) ions onto garden grass, j. bioresource technol. vol.121, pp. 386-395. 11. maranon e., sastre h., (1991), “heavy metal removal in packed beds using apple wastes”, bioresour. technol. vol. 38, pp. 39-43. 12. orhan y., buyukgungor, h. (1993), “the removal of heavy metals by using agricultural wastes. water sci. technol. vol. 28, pp. 247-255. 13. hawrhorne c., winkler h., gomez p., (1995), “removal of cupric ions from aqueous solutions by contact with corn cobs”, sep. sci. technol, vol. 30, pp. 2593. 14. lu d., cao q., li x., cao x., luo f., shao w., (2008),kinetics and equilibrium of cu(ii) adsorption onto chemically modified orange peel cellulose biosorbents, j. hydrometallurgy.http:doi:10.1016/j. hydromet.2008.05.008. 15. el-said a., badawy n., garamon s. (2010), “adsorption of cadmium (ii) and mercury (ii) onto natural adsorbent rice husk ash (rha) from aqueous solutions: study in single and binary system”, j. american science, vol. 12, pp. 400-409. 16. el-sayed, g. o, dessouki, h. a, and ibrahim, s. s,( 2010), biosorption of ni (ii) and cd (ii) ions from aqueous solutions onto rice straw, chemical sciences journal, vol. 20: csj-9. 17. babarinde n., (2012), “kinetic, equilibrium and thermodynamic studies of the biosorption of cd (ii), pb (ii) and zn (ii) from aqueous solutions using coconut leaf”, j. science and technology, vol. 13, no. 1, pp. 430-442. 18. fastoto t., arawande j. (2013), “effect of particle sizes of edta modified and unmodified maize husk on adsorption of fe(ii), cu (ii) and ni (ii) ions from aqueous solution”, j. applied science in environment sanitation, vol. 8, no. 1 pp. 47-52. 19. bulut y., aydin h., (2006) , kinetic and thermodynamics study of methylene blue adsorption on wheat shells, desalination vol.194, pp. 259-267. 20. kavitha d., namasivayam c.,(2007),experimental and kinetic studies on methylene blue adsorption by coir pith carbon , bioresour. technol.vol. 98 , pp. 14-21. 21. ho, y.s., mckay, g., (199), pseudo-second order model for sorption processes, process biochem, vol. 34, pp.451–65. 22. langmuir, i., (1918), "the adsorption of gases on plane surfaces of glass", mica and biosorption of lead, cadmium, and zinc onto sunflower shell: equilibrium, kinetic, and thermodynamic studies 104 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net platinum. j. am. chem. soc., vol. 40, pp.1361–1403. 23. freundlich, h., (1907), "ueber die adsorption in loesungen", z. phys. chem., vol. 57, pp. 385–470. 24. lagergren s., (1898),about the theory of so-called adsorption of soluble substances, kungliga svenska veteskapsakademiens handlingarvol. 24 , pp. 1-39. 25. weber, w. j., morris, j. c., (1963), "kinetics of adsorption on carbon solution", j. sanit. eng. div. am soc civ. eng., vol. 89, pp. 31–59. 26. liu y., (2009), is the free energy change of adsorption correctly calculated?, j. chem. eng. data, vol. 54, pp. 1981-1985. 27. aksu z. and donmez g.,(2003), a comparative study on the biosorption characteristics of some yeasts for remazol blue reactive dye, chemosphere,vol. 50 ,pp. 1075-1083. 28. lodeiro, p., cordero, b., grille, z., herrero, r., vicente, m.e.,(2004), physicochemical studies of cadmium (ii) biosorption by the invasive alga in europe: sargassummuticum, j. biotechnol. and bioeng. vol.88, no.2, pp. 237-247. 29. vincenta, t., taulemessea, j.m., dauvergnea, a., chanuta, t., testaa, f., guibala, e.,(2014), thallium(i) sorption using prussian blue immobilized in alginate capsules, carbohydrate polymers, vol. 99, pp. 517– 526. 30. sulaymon, a.h, mohammed, a.a, al-musawi, t.j.,( 2014), comparative study of removal of cadmium (ii ( and chromium (iii) ions from aqueous solution using low-cost biosorbent, int. j. chem. reac. eng., vol .12, no. 1, pp.1-10. 31. gialamouidis, d., mitrakas, m., liakopoulou, m., (2010), equilibrium, thermodynamics and kinetics studies on biosorption of mn (ii) from aqueous solutions by pseudomonas sp. staphylococcus xylosus and blakeslea trispora cells. j. hazardous materials, vol. 182, pp. 671-680. 32. kumar, k. p., nagendran, r., naresh, k., (2009), "lead biosorption onto waste beer yeast byproduct, a means to decontaminate effluent generated from battery manufacturing industry", electronic journal of biotechnology, vol.10, pp. 168176. 33. sezen, s., sinem, a., mustafa, i., ali, g., celal, d., hulya, y., (2012), dehydrated hazelnut husk carbon: a noval sorbent for removal of ni (ii) ions from aqueous solution. desalination and water treatment, vol. 50, pp. 2-13. 34. gupta s.s., bhattacharyya k.g. (2011), kinetics of adsorption of metal ions on inorganic materials : a review. adv. colloid interface sci. vol. 162. pp. 39-58. 35. ozcan,a., ozcan,a.s., gok,o.,(2007), adsorption kinetics and isotherms of anionic dye of reactive blue 19 from aqueous solutions onto dtmasepiolite, in: a.a. lewinsky (ed.), hazardous materials and wastewater—treatment, removal and analysis, nova science publishers, new york. 36. unuabonah, e.i., adebowale, k.o., oluowolabi,b.i.(2007),kinetic and thermodynamic studies of the adsorption of lead (ii) ions onto phosphate-modified kaolinite clay, j. hazard. mater.vol. 144 ,pp. 386–395. ahmed a. mohammed -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 105 37. wu, f.c., tseng,r.l., juang, r.s.,(2009), initial behavior of intraparticle diffusion model used in the description of adsorption kinetics, chem. eng. j. vol.153 ,pp. 1–8. 38. itodo, a.u., abdulrahman, f.w., hassan, l.g., maigandi, s.a., itodo,h.u.,(2010), intraparticle diffusion and intraparticulate diffusivities of herbicide on derived activated carbon. researcher, vol.2, pp. 74-86. 39. varank, g., demir, a., yetilmzsoy, k., top, s., sekman, e., bilgili, m.,(2012), removal of 4-nitrophenol from aqueous solution by natural low-cost adsorbent. indian j. chem. tech.,vol. 19 pp. 7-25. 40. allen s.j., brown p.a., (1995),isotherm analyses for single component and multicomponent metal sorption onto lignite. j. chem technol biotechnol.vol. 62,no.1, pp.17– 24. 41. sulaymon a.h., mohammed a.a., al-musawi t.j., (2013), competitive biosorption of lead, cadmium, copper, and arsenic ions using algae, environ. sci. and pollut. res.vol. 20, pp.30113023. 42. sulaymon, a. h., and ahmed, k.w., (2008), "competitive adsorption of furfural and phenolic compounds onto activated carbon in fixed column", j. environmental science and technology, vol.42, pp. 392-397. iraqi journal of chemical and petroleum engineering vol.17 no.2 (june 2016) 5368 issn: 1997-4884 thermal osmosis of mixtures of water and organic compounds through different membranes ahmed faiq al-alawy * and ramy mohamed al – alawy ** * university of baghdad – chemical engineering department (e-mail: ahmedalalawy@yahoo.com) ** university of baghdad – chemical engineering department (e-mail: rami_mo80@yahoo.com) abstract the present work aimed to study the efficiency of thermal osmosis process for recovery of water from organic wastewater solution and study the factors affecting the performance of the osmosis cell. the driving force in the thermo osmosis cell is provided by a difference in temperature across the membrane sides between the draw and feed solution. in this research used a cellulose triacetate (cta), as flat sheet membranes for treatment of organic wastewater under orientation membrane of active layer facing feed solution (fs) and draw solution (ds) is placed against the support layer. the organic materials were phenol, toluene, xylene and btx (benzene, toluene, and xylene) used as feed solution. the osmotic agent in draw solution was sodium chloride salt. the membranes have high rejection percentage for nacl and organic materials. in this research, the operating conditions that have been studied are: temperature of draw and feed solution (18 – 45 °c) and the operating time of process was (0 – 3) hours. it was found that water flux in thermal osmosis process increases with increasing temperature of draw and feed solution ( by average ratio 1:2), and decreases with increasing operating time. key words: thermal osmosis, wastewater solution introduction due to fast depletion of the freshwater resources, the world is facing crisis of fresh water all over the world. the industrial and domestic activities have polluted the surface water as well as ground water up to a greater extent [1]. hence the cost of removal of organic pollutants from water has been increased remarkably in last few years. there are several technologies for treating wastewaters. and this poses a great challenge to chemical engineer’s to develop low cost effective and environmentally safe disposal and treatment methods. organic compounds in water derive from three major sources: (1) the breakdown of naturally occurring organic materials, (2) man-made chemicals from domestic and commercial activities, and (3) treatment additives and chemicals formed during reactions that occur during water treatment and transmission [2]. iraqi journal of chemical and petroleum engineering university of baghdad college of engineering mailto:ahmedalalawy@yahoo.com mailto:rami_mo80@yahoo.com thermal osmosis of mixtures of water and organic compounds through different membranes 54 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net the health effects of organic compounds can vary greatly according to the compound, which can range from being highly toxic to having no known health effects. the health effects of organic compounds will depend on the nature of the organic compound, the level of exposure, and the length of exposure. for example, long-term exposure to volatile organic compounds can cause damage to the liver, kidneys, and central nervous system. short-term exposure to volatile organic compounds can cause eye and respiratory tract irritation, headaches, dizziness, visual disorders, fatigue, loss of coordination, allergic skin reactions, nausea, and memory impairment [3]. several treatment methods are available for treating the organic wastewater includes adsorption and membranes separation, anaerobic processes, and combined applications of flotation and coagulation processes, stripping and oxidation. all of these are used for treating organic and inorganic waste. most of these methods suffer from some drawbacks, such as high capital and operational cost, regeneration cost, and problem of residual disposal [2]. in recent decades various membrane separation processes have been developed and utilized in the field of potable water purification, and more recently in the treatment of various process and waste liquors. some of the membrane processes are capable of removing both dissolved and particulate contaminants. a wide variety of membrane separation processes exist. these differ from one another in the model and configuration of the membrane, the mechanism of trans-membrane transport for various water solution components, the nature of the process driving force and other features. membrane separation processes may be classified and categorized by a number of criteria. a basic distinction between the individual methods is the process driving force used to purify or concentrate a solution, which may be a pressure gradient, concentration gradient, electrical potential gradient or temperature gradient. in some instances, and specifically in some processes under development, more than one driving force may be used. membrane processes can be classified with respect to the process driving force such as pressure gradient, electrical potential, concentration gradient, temperature gradient, and combined driving forces [4]. nanofiltration (nf) membranes reject organic compounds with a molecular weight of 200 – 500 or above. nanofiltration has been used industrially in water softening applications, removal of dissolved organic substances and fractionation of low and high molecular weight organic substances [5]. colloids, suspended solids and high molecular weight organic molecules do not pass through the ultrafiltration (uf) membrane with water. they are rejected and remain in the concentrate stream. reverse osmosis typically removes 95 – 99.5% of total dissolved inorganic solids and 95 – 97% of dissolved organic solids. the microfiltration (mf) membrane rejects particles and dissolved macromolecules larger than 0.1 μm. despite more recent technology advancements, membranes systems, by definition, still need to provide enough driving force to overcome the intrinsic osmotic pressure in brackish or seawater. a more energy efficient way is to harness the force of nature, osmotic pressure, the natural pressure that drives water molecules to the saltier side across a semipermeable membrane. forward osmosis (fo) does just that. the process itself is not new. forward (or direct) osmosis is an ahmed faiq al-alawy and ramy mohamed al alawy -available online at: www.iasj.net ijcpe vol.17 no.2 (june 2016) 55 isothermal process that refers to the diffusion of water through a semipermeable membrane (i.e. dense and water selective membrane, hydrophilic membrane such as cellulose triacetate) from a higher water concentration side to the osmotic agent side. the advantage comes when the salt in the draw solution (ds) can be removed efficiently and cheaply. the process is a simple two-part process. a draw solution with salt content higher than the water to be purified is used to draw water across a semipermeable membrane. water comes to the draw solution without external energy or pressure. after water is drawn to the saltier side, the draw solution is processed to remove the salts. the salts are subsequently recovered and reused. an fo system with its low energy operation, close to zero liquid discharge operation, ingredients safe to handle and completely recoverable, low capital, maintenance and replacement cost, and the possibility to be completely off the grid makes it an ideal choice for remote and small operations. the development of a suitable fo membrane became the most critical piece for realizing the potential of the fo technology [6]. in this research, study the efficiency of thermal osmosis process as a new application for recovery of pure water from organic solution. sodium chloride was used as draw solution (ds), and organic compounds such as phenol, toluene, btx, and xylene in water were used as feed solution (fs). used three types of membranes are cellulose triacetate (cta), cellulose acetate (ca), and thin film composite (tfc) in the thermo osmosis to achieve high recovery percentage. theoretical thermal osmosis thermo-osmosis is a phenomenon in which matter is driven through a membrane or an orifice from one chamber to another on account of the temperature difference between the two chambers. this can occur for a single fluid or a mixture of fluids. in a system without a membrane or a barrier, temperature gradient can give rise to concentration gradient and this phenomenon is called thermal diffusion. thermo-osmosis was the first non-equilibrium phenomenon which was extensively studied from experimental and theoretical angles, both for the case of liquids, gases and gaseous mixtures. there are a number of factors, which govern the occurrence of the phenomenon of thermo-osmosis. it is essential to choose a system such that the dimensions of the pores of the membrane are comparable to the mean free path of the permeating molecules. the deficiency is more serious in case of liquids. in case of gases, appreciable difference of pressure has been observed as a result of themosmosis through natural rubber membranes [7]. thermo-osmosis of water through a cellophane membrane has been reported by rastogi, blokhra and agrawal. experimental studies on thermo-osmosis of liquids (methanol and water) across du pont 600 cellophane were reported for the first time by rastogi and singh. studies on thermo-osmosis of water through cellulose acetate membrane support predictions by rastogi and singh based on correlation between the existence of thermo-osmosis and the membrane pore size. extensive studies on thermoosmosis have been carried out using various hydrophobic and hydrophilic membranes [8]. water transfer through various hydrophilic and hydrophobic polymer membranes was observed under a temperature gradient and analyzed by a theory based on non-equilibrium thermal osmosis of mixtures of water and organic compounds through different membranes 56 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net thermodynamics. water is transferred through hydrophilic polymer membranes from the cold side to the hot side because the transported entropy of water in the membrane is smaller than the molar entropy of water in the external free solutions. in contrast, water is transferred through hydrophobic polymer membranes from the hot side to the cold side because the transported entropy of water in the membrane is larger than the molar entropy of water in the external free solutions [9]. experimental setup and procedure two types of solutions have been prepared to conduct experiments on the forward osmosis process (see figure1). the first was the draw solution (nacl – h2o), which was prepared in the glass vessels by dissolving the nacl salt in 2 liter of tap water. the second solution was the feed solution, which is prepared in the glass vessels by dissolving organic substance, these substances were toluene, phenol, xylene, and btx to obtain different concentrations of one organics substances in 2 liter of tap water. draw solution was pumped to one side of the membrane, and feed solution (organic solution) was pumped to the other side of the membrane by diaphragm booster pumps. the osmosis cell was designed so that both the draw solution flow and feed solution flow tangent to the membrane in the same direction (i.e. co-current flow). to change the temperature of feed and draw solutions submersible spiral copper tube (i.e. coil) was used in the vessel. the hot or cold water was pumped through the spiral tube, the temperature of feed and draw solutions controlled by microcomputer temperature controller. water flux was determined by measuring of the weight difference in the draw solution or feed solution per unit of time and per unit of membrane area. the concentrations of the nacl solution, organic solution were measured by the conductivity meter and spectrophotometer respectively. fig. 1, (a) schematic diagram ahmed faiq al-alawy and ramy mohamed al alawy -available online at: www.iasj.net ijcpe vol.17 no.2 (june 2016) 57 fig. 1, (b) experimental picture of osmosis process system results and discussion the experiments conducted in the presence of temperature difference at various types of feed solution and membranes explained the mechanisms of temperature effect on water transport across the membrane. figures 2 to 9 show the effect of operating temperature of feed and draw solutions on water flux for different organic materials (toluene, phenol, btx, and xylene) as feed solutions. these figures indicate that the water flux across the cta membrane increasing when the operating temperature for ds and fs increased. the increase of the water fluxes with the rise of feed and draw solutions temperatures can be explained by several factors: fluid viscosity, concentration polarization, water permeability, mass transfer coefficient, heat transfer coefficient, and solute resistivity of membrane. the increase of ds temperature in the range 18 45 °c (fs temperature constant at 45 °c) resulted in the net increase of water flux of 34.5 % in the case of toluene as feed solution, 58.8 % (phenol fs), 21.3 % (btx fs) and 38.9 % (xylene fs). the temperature elevation in ds side from 18 to 45 °c led to an increase in ds osmotic pressure by 6.9 % as calculated from van’t hoff law. the increase of osmotic pressure (i.e. the driving force for water flux) due to temperature elevation in ds side, it is one of the responsible factors for such enhancement in water flux. on the other hand, the increase of ds temperature from 18 – 45 °c increased the draw solute diffusivity and water molecular diffusion coefficient, and decreased viscosity of draw solution. while, the increase in fs temperature in the range of 18 – 45 °c (ds temperature = 45 °c) was shown to produce a much more noteworthy water flux increase by 135.8 % (toluene fs), 145 % (phenol fs), 88.5 % (btx fs) and 81.2 % (xylene fs). increasing fs temperature vessel from 18 to 45 °c led to decrease of fs kinematic viscosity from 9.6843 x 10-7 to 6.2945 x 10-7 m2/s. in other words, the percentage of decrease in kinematic viscosity is equal to 35.1%, which corresponded to an increase of diffusivity from 1.526 x 10-9 to 2.4532 x 10-9 m2/s (i.e. 60.69 %). this behavior is in agreement with [10]. therefore, if the temperature of ds was constant and increase in the temperature of the fs occurred from 18 to 45 °c, the water flux was more than if the ds temperature was increased from 18 to 45 °c at constant fs temperature. thermal osmosis of mixtures of water and organic compounds through different membranes 58 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net this was because in the osmosis cell the feed solution was against the active layer of the membrane and the pure water transferred from organic solution (fs) to sodium chloride solution (ds). the change in the fs temperature affected the physical properties of feed solution, and these properties have a positive impact on the water flux through membrane. the figures 10 to 13 show the effect of temperature in the feed vessel (td and tf) and the temperature across both sides of the membrane (tdc and tfc) on water flux for different feed solution. the influence of the difference in temperature on the water flux was not the difference in temperature between the draw and the feed solution in the vessels, but the real difference in temperature for thermo osmosis process was on both sides of the membrane in the cell. the temperature in the feed vessel was different from the temperature in the cell (across the membrane). this depends on the temperature on the other side of membrane and recirculation the fs and ds between vessel and osmosis cell. therefore, sometimes the temperatures in the cell caused higher or lower than the vessel temperature. in these figures, higher water flux was obtained when the feed draw temperature is equal to 45 – 45 °c for different organic materials and at constant time (t = 3 h). while, lower water flux was acquired when the feed draw temperature is equal to 18 – 18 °c. figures 14 and 15 show the effect of the organic materials types on the flux for cta membrane. figure 14 show the difference in water flux which was slightly for four organic materials (toluene, phenol, btx, and xylene) when they used as feed solutions. this is due to the little difference in the molecular weights, in other words, nearly the same osmotic pressure of feed solution for these substances. at the same conditions, toluene has a higher flux of the other organics component, the order of the water flux was toluene > phenol > btx> xylene. this behavior can be explained by theories of osmosis and the mechanisms for solute rejection [11] and [12]. in this research, the study of different types of membranes (cta, ca, and tfc) to illustrate the effect of operating temperature on both sides of the membrane in the thermo osmosis process. the effect of temperature on water flux was the same behavior in the three osmosis membranes which used in the fo process. figures 16 and 17 show the water flux with time and draw – feed temperature respectively for different membranes. obviously, the cta membrane has the highest water flux than ca and tfc membranes. the majority of common tfc reverse osmosis membranes are typically composed of three layers (ultrathin top, inter-support, and a thicker). these layers are necessary for mechanical strength in high hydraulic pressure, but it considerably reduces flux based on internal concentration polarization in fo cell, which operating at very low hydraulic pressure. while, support layer in cellulose triacetate (cta fo) membrane was allow to minimize internal concentration polarization to increase water flux. these results for cta and tfc membranes are consistent with [13]. in the thermo osmosis process when the organic solution faces the active layer of the membrane and nacl – h2o solution facing the support layer of the membrane, the flux decreased with operating time. the value of flux is decreased especially during two hour. ahmed faiq al-alawy and ramy mohamed al alawy -available online at: www.iasj.net ijcpe vol.17 no.2 (june 2016) 59 fig. 2, flux vs. time at different draw temperature (cta membrane, tf = 45 o c, qf = qd = 12 l/h, cf = 50 ppm, cd = 35 g/l and toluene) fig. 3, flux vs. time at different feed temperature (cta membrane, td = 45 o c, qf = qd = 12 l/h, cf = 50 ppm, cd = 35 g/l and toluene) thermal osmosis of mixtures of water and organic compounds through different membranes 60 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net the water flux takes a downward slightly after the two hour of operating time. the reason of this behavior was that the pure water transfer from the fs through the membrane to the ds, thus led to reduce the concentration of ds (i.e. reduced the osmotic pressure) which represents a driving force for permeate flux. it must be explained as follows by increasing the operating time, the organic fouling rate (concentration polarization) was increased on the surface of membrane, and led to diminish the rate of the solvent through the membranes. the results of this declined in water flux with increased time compatible with both jeffery et al., (2005), [14] and [15]. fig. 4, flux vs. time at different draw temperature (cta membrane, tf = 45 o c, qf = qd = 12 l/h, cf = 50 ppm, cd = 35 g/l and phenol) fig. 5, flux vs. time at different feed temperature (cta membrane, td = 45 o c, qf = qd = 12 l/h, cf = 50 ppm, cd = 35 g/l and phenol) ahmed faiq al-alawy and ramy mohamed al alawy -available online at: www.iasj.net ijcpe vol.17 no.2 (june 2016) 61 fig. 6, flux vs. time at different draw temperature (cta membrane, tf = 45 o c, qf = qd = 12 l/h, cf = 50 ppm, cd = 35 g/l and btx) fig. 7, flux vs. time at different feed temperature (cta membrane, td = 45 o c, qf = qd = 12 l/h, cf = 50 ppm, cd = 35 g/l and btx) thermal osmosis of mixtures of water and organic compounds through different membranes 62 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net fig. 8, flux vs. time at different draw temperature (cta membrane, tf = 45 o c, qf = qd = 12 l/h, cf = 50 ppm, cd = 35 g/l and xylene) fig. 9, flux vs. time at different feed temperature (cta membrane, td = 45 o c, qf = qd = 12 l/h, cf = 50ppm, cd = 35 g/l and xylene) ahmed faiq al-alawy and ramy mohamed al alawy -available online at: www.iasj.net ijcpe vol.17 no.2 (june 2016) 63 fig. 10, flux vs. different feed draw temperature (cta membrane, qf = qd = 12 l/h, cf = 50 ppm, cd = 35 g/l and toluene) fig. 11, flux vs. different feed draw temperature (cta membrane, qf = qd = 12 l/h, cf = 50 ppm, cd = 35 g/l and phenol) thermal osmosis of mixtures of water and organic compounds through different membranes 64 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net fig. 12, flux vs. different feed draw temperature (cta membrane, qf = qd = 12 l/h, cf = 50 ppm, cd = 35 g/l and btx) fig. 13, flux vs. different feed draw temperature (cta membrane, qf = qd = 12 l/h, cf = 50 ppm, cd = 35 g/l and xylene) ahmed faiq al-alawy and ramy mohamed al alawy -available online at: www.iasj.net ijcpe vol.17 no.2 (june 2016) 65 fig. 14, flux vs. time at different types of organic (cta membrane, td = 45 o c, tf = 45 o c, qf = qd = 12 l/h, cf = 50 ppm and cd = 35 g/l) fig. 15, flux vs. different feed draw temperature (cta membrane, qf = qd = 12 l/h, cf = 50 ppm and cd = 35 g/l) thermal osmosis of mixtures of water and organic compounds through different membranes 66 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net fig. 16, flux vs. time at different types of membranes (tf = 45 o c and td = 45 o c, qf = qd = 12 l/h, cf = 50 ppm, cd = 35 g/l and phenol) fig. 17, flux vs. different feed draw temperature at different types of membranes. (qf = qd = 12 l/h, cf = 50 ppm, cd = 35 g/l, time = 3 h and phenol) ahmed faiq al-alawy and ramy mohamed al alawy -available online at: www.iasj.net ijcpe vol.17 no.2 (june 2016) 67 conclusion thermo osmosis process can be used for recovery of water from organic solution. it may be used a suitable alternative to other processes as lower cost. the real impact of the driving force in thermo osmosis process was temperature on both side of the membrane in the cell, not in the feed vessel. the water flux produced from the osmosis cell increase by increasing the temperature of draw solutions and feed solution. the effect of feed temperature on water flux was higher than of draw temperature. for different types of membranes with the same conditions, the order of water flux was given by cta > ca > tfc. the averages ration increase in water flux for cellulose triacetate is about 1: 2.1 than cellulose acetate and 1: 5.9 than thin film composite. cta, ca and tfc membranes may be considered suitable for the thermo osmosis process. the difference in flux through the membrane was slightly with different types of organic materials (phenol, toluene, xylene and btx). the difference in flux through the membrane was slightly with different types of organic materials. the water flux decreases with operating time due to the decrease in driving force. the water flux in the osmosis cell increased with increasing concentration of draw solutions (nacl – h2o) and decreasing concentration of feed solution (organic solution). while, the flux increases by increasing the flow rate of feed solution and decreases by increasing the flow rate of draw solutions. the recovery percentage of water increased with increasing operating time and temperature of osmosis cell. references 1armour, m. a., 1991. hazardous laboratory chemicals disposal guide. crc press, boca raton. 2bouchelta, c., medjram, md. s., bertrand, o. and bellat, j. p., 2008. preparation and characterization of activated carbon from date stones by physical activation with steam. journal of analytical and applied pyrolysis. 82, 70-77. 3edzwald, j. k., 1999. water quality and treatment a handbook on drinking water sixth edition 4jinxing, ma and zhiwei, w., 2013. organic matter recovery from municipal wastewater by using dynamic membrane separation process. chemical engineering journal. 219, 190–199. 5rautenbach a. r. and grqschl a., 1990. separation potential of nf membranes. desalination. 77, 73– 84. 6gebreyohannes, a. y., curcio, e., poerio, t. and mazzei r., 2015. treatment of olive mill wastewater by forward osmosis. separation and purification technology.147, 292–302. 7soowhan k. and mench m.m., 2009. investigation of temperaturedriven water transport in polymer electrolyte fuel cell: thermoosmosis in membranes journal of membrane science. 328, 113–120 8villaluenga j.p.g, seoane b., barragán v.m. and ruiz-bauzá c., 2006. thermo-osmosis of mixtures of water and methanol through a nafion membrane. journal of membrane science, 274, 116–122. 9simonič m. and lobnik a., 2011. the efficiency of a hybrid flocculation/uf process for a real dye-house effluent using hydrophilic and hydrophobic membranes. desalination. 271, 219– 224 10mccutcheon j. r. and elimelech m., 2006. influence of concentrative and dilutive internal concentration polarization on flux behavior in forward osmosis. thermal osmosis of mixtures of water and organic compounds through different membranes 68 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net journal of membrane science. 284, 237–247. 11slein m.w., sansone e.b., 1980. degradation of chemical carcinogens, van nostrand reinhold, new york. 12zarrin e., mahmoud e. and hosseini m. s., 2011. optimization of a novel method for determination of benzene, toluene, ethylbenzene, and xylenes in hair and waste water samples by carbon nanotubes reinforced sol–gel based hollow fiber solid phase microextraction and gas chromatography using factorial experimental design, journal of chromatography a. 1218, 3400– 3406 13muhammad q., 2013. performance of forward osmosis using various membranes. m.sc. thesis, american university of sharjah. 14ge, z. and he, z., 2012. effect of draw solutions and membrane conditions on electricity generation and water flux in osmotic microbial fuel cells. bioresource technology. 109, 70-76. 15abdulhakeem, a. a., james, a. m., stuart, j. k., william, e. p., long, d. n. and menachem, e., 2013. removal of trace organic contaminants by the forward osmosis process. separation and purification technology.103, 258– 266. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.20 no.3 (september 2019) 39 – 47 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: saifalden y. alssafar, email: saifpet@yahoo.com, name: faleh h. m. al-mahdawi, email: fhmetr@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. certain assessment of using mwcnt nps in drilling fluid to mitigate stick-slip problem during drilling operation system saifalden y. alssafar and faleh h. m. al-mahdawi petroleum engineering department, university of baghdad abstract stickslip is the continuous stopping& release of the bit/bha due to the irregular down-hole rotation prompted by the existing relationship between the friction torque and the torque applied from the surface to free the bit. friction coefficient between bha and wellbore is the main player of stick slip amount, which can be mitigated by support a good lubricators as additives in drilling mud. mathematical (or empirical) solves should be done through adjusting all parameters which supposed to reduce stickslip as low as possible using different models, one of the main parameters is drilling mud. as per nanoparticles drilling fluid is a new technology that offers high performance it’s necessary to find out the relationship between the use of nano fluid and the minimum stickslip vibration. in this study (multiwall carbon nano tube) will be used as a nanoparticles in fresh water bentonite mud and polymer mud by five tests per each one to find out the coefficient of friction and used it in a special torque and drag software as a part of drilling vertical well simulation to calculate expected bottom hole torque within five different nano concentration per each mud type. in fresh water bentonite mud torque reduction was from 4000 ft-lb to 3500 ft-lb, while in polymer mud torque failed and didn’t reduce, so it raised from 2050.88 ft-lb to be around 2200 ft-lb. keywords: stick – slip problem, drilling mud, nano particles fluids, mwcnt, drill string, bha vibrations received on 13/01/2019, accepted on 19/04/2019, published on 30/09/1029 https://doi.org/10.31699/ijcpe.2019.3.6 1introduction big amount of vibration during drilling formation frequently occurs, where in one drilling run all three main vibrations may occur together (torsional vibration, axial vibration and lateral vibration). solutions in both of technologies and methodologies paths can be together a useful key in order to reduce down hole vibration. unacceptable levels of vibration can cause drill string fatigue, poor directional tendencies, premature bit failure, stalling of the top drive or rotary table, hole enlargement, mwd tool failure and bit /stabilizer / tool joint wear, stick-slip vibration represent the torsional type and it the biggest trouble maker between the three down hole vibrations. ‎[1], ‎[2], ‎[3] nowadays, directional drilling models are the most preferred for many reasons, therefore there are needs of using complex bottom hole assembly design (bha), where this bha will be longer than the normal one and includes very thin clearance in some parts, so this drilling operation will create high torque and vibrations, hence such like these operation should comply with make vibration monitoring and controlling a key in drilling optimization. a number of operator companies have become aware of the importance of controlling vibration and have created programs to raise awareness and generate control strategies.‎[4], ‎[5] 2aim of this study in this study we work to find out direct drilling mud effects on torsional vibration(stick-slip) during drilling by finding relationship between the problem of stick slip during drilling and the adding of nanoparticle materials (using multiwall carbon nanotubes (mwcnts)] to the drilling fluid within different concentrations. 3methodology carbon nano tube (cnt) is one of the allotropic forms of carbon with cylindrical shape structure. it is consist of carbon atoms which are connected in hexagonal shapes. ‎[6], ‎[7], ‎[8]. the main character of cnt that is the length of cnt can be up to 132,000,000 times greater as compared to its diameter which is very high and attractive as compared to other materials. in additional to cylindrical structure, important properties of cnt are exceptionally improved such as unique electrical characteristics, mechanical strength and thermal conductivity ‎[2]. cnt is one of the strongest materials in terms of tensile strength and elastic modulus ‎[9]. https://doi.org/10.31699/ijcpe.2019.3.6 s. y. alssafar and f.h. m. al-mahdawi / iraqi journal of chemical and petroleum engineering 20,3 (2019) 39 47 04 fig. 1. multiwall carbon nanotube mwcnt ‎[10] fig. 2. single wall carbon nanotube swcnt ‎[10] 3.1. diagnostic test a. the lubricity tester lubricity tester is often used to assess and guess the influence made by a drilling mud additive with regards to friction force. the most common tester, the fan or ofite model 212, is normally used in a laboratory setting (as shown in fig. 3). this extreme pressure (ep) and lubricity tester is intended to simulate contact between a drill string and casing, it consists of a rotating ring and stationary block, which are submerged in the drilling fluid. since particular load under wellbore conditions is hard to determine, classically fixed levels of contact forces are used. we can measure by this device lubricity factor or coefficient of friction (cof), mud torque reading and mud cake friction (kf). fig. 3. ofite lubricity tester ‎[11] there are some features make this model device is still up to date of measuring friction factor, the following features conclude them:  the accuracy of reading data by digital control.  the motor automatically maintains torque as a constant speed when force is applied to the ring and block. so no need to manual speed adjustments.  simple use instruction, makes testing quick and easy, i.e. manual speed control, pre-set speeds (60, 200, 600, and 1000 rpm) and torque zeroing.  has the ability of recording torque reading and temperature with respect to time in simple and clear monitor. ‎[11] 3.2. ultrasonic actions an ultrasonic treatment is the most common solution to disperse the nanoscale particles in liquid media. it used with/ without chemical dissolving agents. in typical dispersion operations, sonication required about (12-36) hrs. to ensure influence dispersion with appropriate solvent. a. sonication organization there are three major stages that ultrasonic system working on it: generator to transfer ac power energy (high voltage), converter works as modifier of that energy into vibration and probe (horn) enlarges and contracts longitudinal status. by changing the amplitude setting we can get a various cavitation fields. during sonic operation the solution could get high temperatures, so it may need close observation ‎[12], [13]. b. ultra-sonic device (elma e series) ‎[14]  sweep (cleaning): safely clean metal, glass, electronic, and plastic parts  degas(bubble remover): rapidly remove gasses from liquids  normal(dispersion): dissolve, homogenize, disperse, mix and emulsify lab samples s. y. alssafar and f.h. m. al-mahdawi / iraqi journal of chemical and petroleum engineering 20,3 (2019) 39 47 04 fig. 4. elma ultrasonic device e series the elmasonic e series consists of 8 diverse unit dimensions with tank volumes alternating from 1.75 up to 28 litre. they are formed with efficient 37 khz ultrasonic power transducers of the latest generation. it is easy to work in lab condition and safe to be left alon to automatic switchoff after 12 hours for more safety. 3.3. (stick-slip) software assumption using some parameters of the real rig and by input the variable values of friction factors that got from the experimental work for 10 samples, this software will calculate a new torque values (ft-lb) per each sample result. in this research rig idc-56 is used to simulate drilling a vertical well, 12 1/4” section hole, wob=(25 30 klb. for polymer mud, and wob =12 14 klb. for fwb mud where it commonly used on shallow depth), rpm= 45 with fixed friction factor of 0.25 ft-lb between drilling string and 13 3/8” casing. the drilling bit& bha designed as follow: table 1. bha design in software item description (od) id (weight) length cum. length # a (in) (in) (lbpf) (m) (m) 1 pdc a 8.000 3.500 138.52 0.44 0.44 2 near-bit stabilizer with fv a 8.000 3.000 147.22 2.31 2.75 3 mwd directional + gamma a 8.000 4.000 128.48 9.90 12.65 4 1 x 8" drill collar a 8.000 2.750 150.70 9.14 21.79 9 1 x 8" drill collar a 8.000 2.750 150.70 9.14 87.45 10 x-over sub a 8.000 2.875 149.18 0.78 88.23 11 2 x 6 3/4" drill collar a 6.750 2.750 101.50 18.28 106.51 12 [15 x 5"]heavy wall drill pipe(hwdp) 5.000 3.000 49.30 140.70 247.21 13 5" dp a 5.000 4.276 21.92 9.00 256.21 4experimental work this workshop is prepared to develop the rheological characterize of drilling fluid. the increase of some rheological parameters above the desired limit can cause some issues such as stuck pipe, lost circulation etc. for example, the preferred drilling fluid has minimum plastic viscosity, and gel strength with a flat curve in order to reduce the required pump pressure to start circulation again. to reach these aims of the study, ten experiments tests were directed in bottom hole conditions, where hot roll was used in order to heat and rotate the mud samples for four hours in around 250 degree fahrenheit, viscometer model 800 was used to measure mud rheology, benchtop meter to get ph, filter press device to determine the water loss multi-mixer model 9b fan to ensure mix mud in high efficient and quick minor, sonication system with solvent to disperse nanoparticle in mud and mud lubricity tester to catch the friction factor for each test sample. 4.1. sample preparation to insure good nano-mwcnt dispersion the following procedure was conducted: a. mixing mwcnt powder in distilled water and put it into ultrasonic bath. b. mixing surfactant in water type distilled to raise the efficiency of nanoparticles dispersion and put it into ultrasonic bath too. c. merge the two solutions were prepared in above and put them again in the ultrasonic bath for 7-8 hours. d. five samples (cups) were made, as per the first sample was blank then adding 0.35, 0.7, 1.05, 1.75 gm of mwcnt consequently to fwb and adding 0.1, 0.2, 0.3, 0.5 gm to polymer mud. e. nano-colloidal solution added to fluid system in different concentrations as follow: 1280.5 cc of polymer mud. 2350 cc of fwb. s. y. alssafar and f.h. m. al-mahdawi / iraqi journal of chemical and petroleum engineering 20,3 (2019) 39 47 04 4.2. mixing mud a. preparing polymer mud preparing was made based on table 2, the materials were mixed by multi mixer fann (9b) table 2. polymer mud composition composition unit blank mixing time distilled water cc 280.5 sodium chloride gm 61.35 10 min potassium chloride gm 11.66 12 min caustic soda gm 1.05 12 min soda ash gm 1.55 12 min starch gm 12.5 12 min pac lv gm 1.04 12 min xanthan gm 0.55 12 min limestone (50-75 μ) gm 87.65 12 min 1using five individual samples of blank polymer mud nano material were added in different concentration and mixed for 20 min. 2by using rotational viscometer model ofite 800, viscosity measured by at 120 ο f 3put arranged mud in hotroll for assessing rheological properties in downhole circumstance at 250 ο f amid 4 hrs. 4calculate the viscosity and gel strength at 120 ο f by rotational viscometer type (ofite 800) 5measure mud filtrate volume through api filter press type (fan 300series) at laboratory temperature and pressure of 100 psi. 6appraise lubricity factor by using (ep/ lubricity) tester b. prepare bentonite mud table 3. fwb mud composition composition unit blank sample mixing time distilled water cc 350.0 bentonite gm 22.50 25 min the mud prepared based on table 3 as follow: 1aging arranged mud in lab. temperature within 16 hrs. to ensure 2nano material added to mud sample cups in certain concentrations and mixed at 20 min. 3viscosity & gel strength measured at 120 ο f using rotational viscometer model (ofite 800). 4measure filtrate volume by api filter press model fan 300series at room temperature and 100 psi pressure work. 5determine lubricity factor (cof) by the use (ep/ lubricity) tester. c. preparation of nano material the following steps are concluding preparing of mwcnt nano material for all tests: 5results and discussion 5.1. polymer mud test with mwcnt additives table 4 is demonstrations the changes in mud rheology when we added mwcnt to 280.5 cc of polymer mud by various concentrations respectively. table 4. polymer mud rheology with mwcnt additives in two conditions rheology (120 °f) cup 1 cup 2 cup 3 cup 4 cup 5 bhr ahr bhr ahr bhr ahr bhr ahr bhr bhr av 25 21.5 31.5 20.5 30 23.5 35.5 26.5 45 32.5 rpm 600 50 43 63 41 60 47 71 53 90 65 rpm 300 30 26 42 28 39 31 47 33 59 40 pv cp 20 17 21 13 21 16 24 20 39 25 yp lb/100 ft 2 10 9 21 15 18 15 23 13 20 15 rpm 200 22 19 32 21 30 23 32 25 46 30 rpm 100 14 12.5 22 13 21 14 24 15 30 19 rpm 6 3 3.5 5 3 5 3 5 4 7 4 rpm 3 2 2.5 4 2.5 4 2.5 4 2.5 6 3.5 gel 10 s 3 3 6 2.5 4 3 5 3 7 4 gel 10 min 4 4 8 4 7 5 7 5 9 5 ph 12.46 12.21 12.80 10.34 12.73 10.52 12.79 10.41 12.77 10.61 api fl, cc 2.2 3.8 3.5 3.2 3 settlement no yes no no no no no no no no filter cake 1/32 1/32 1/32 1/32 1/32 foam no no no no no no no no no no water torque reading 33.7 36.0 36.1 33.9 36.2 mud torque reading 20.1 22.8 22.8 23 23.5 lubricity factor 0.2028 0.2153 0.215 4 0.2306 0.230 7 torque reduction mud cake friction (kf) 0.2046 0.1302 8 0.1302 8 0.1357 8 0.1396 0 s. y. alssafar and f.h. m. al-mahdawi / iraqi journal of chemical and petroleum engineering 20,3 (2019) 39 47 04 table 5. polymer mud rheology with mwcnt additives rheology (120 °f) blank 0.1 gm 0.2 gm 0.3 gm 0.4 gm av 21.5 20.5 23. 5 26.5 32.5 rpm 600 43 41 47 53 65 rpm 300 26 28 31 33 40 pv 17 13 16 20 25 yp 9 15 15 13 15 rpm 200 19 21 23 25 30 rpm 100 12.5 13 14 15 19 rpm 6 3.5 3 3 4 4 rpm 3 2.5 2.5 2.5 2.5 3.5 gel 10 s 3 2.5 3 3 4 gel 10 min 4 4 5 5 5 ph 12.21 10.34 10.5 2 10.4 1 10.61 api fl, cc 2.2 3.8 3.5 3.2 3 settlement yes no no no no filter cake 1/32 1/32 1/3 2 1/32 1/32 foam no no no no no water torque reading 33.7 36.0 36. 1 33.9 36.2 mud torque reading 20.1 22.8 22. 8 23 23.5 lubricity factor 0.202 8 0.2153 0.21 54 0.230 6 0.230 7 torque reduction mud cake friction (kf) 0.204 6 0.13028 0.130 28 0.135 78 0.1396 0 fig. 5. plymer mud parametes with mwcnt (lubricity factor & mudcake friction*10) in the graph 5 noticed that no big change in cof with increasing nano grams gradually per each test, with a little increase of cof to improve that mwcnt doesn’t enhance friction resistance when we add it to polymer mud and we have to try another nanomaterial. it’s also clear that mwcnt makes the problem of mud filtrate is bigger which leads to some other issues like formation damage or wall problems. we can find that mwcnt is optimized lifting cutting and hole cleaning by increasing yp and 10 min gel, so this type of nano material is valuable in fast drilling purpose especially in vertical wells, however we should avoid adding nwcnt to polymer mud if stickslip is the major expected problem. it’s also clear that mwcnt makes mud filtrate somewhat bigger than blank test which could leads to some other issues like formation contamination or wall problems. we can find that mwcnt is optimized lifting cutting and hole cleaning by increasing yp and 10 min gel, so this type of nano material is valuable in fast drilling purpose especially in vertical wells; however we may avoid adding mwcnt to polymer mud if stickslip is not the major expected problem. table 6. cof & torque and drag software reading with mwcnt rheology -------gm 0.1 gm 0.2 gm 0.3 gm 0.4 gm lubricity factor 0.2028 0.2153 0.2154 0.2306 0.2307 torque reading 2050.88 2201.79 2201.79 2303.02 2303.02 fig. 6. torque reading (polymer mud + mwcnt fig. 6 show that there is a little increase in torque reading occurs in the test sample since mwcnt was added and it proportionally sensed to that nanomaterial. fig. 7. (polymer mud + mwcnt) torque reading with trend line as shown in fig. 7, the relationship between torque reading and mwcnt additives in polymer has acceptable trend line with (r 2 =0.8579) within linear equation y= 605.51x +2091 as shown in fig. 7 that means using mwcnt as nano material is purely a proportional relationship toward torque increasing, so to reduce downhole friction is unsuccessful in case we used mud type “polymer”. s. y. alssafar and f.h. m. al-mahdawi / iraqi journal of chemical and petroleum engineering 20,3 (2019) 39 47 00 polymer mud has lower cof than fwb mud in wide range then polymer would certainly reduce friction positively, however in drilling high angle wells or horizontal well there is extra requirement of reducing torque as much as possible therefore we have to keep looking for another nanomaterial to cover drilling requirements. a. fresh water bentonite mud test with mwcnt additives in this job’s package, fwb mud was used with 350 ml. and adding mwcnt as (0.35, 0.70, 1.05, 1.75) gm. mwcnt per each test’s cup respectively, in ratio configuration: (o%, 0.1%, 0.2%, 0.3%, 0.5%) % wt. the mud parameters recorded in table (7) for each amount of mwcnt individually in. table 7. fwb mud rheology with mwcnt additives rheology (120 °f) ------0.35 0.70 1.05 1.75 av 18.5 26. 5 30 36.5 43. 5 rpm 600 37 53 60 73 8 7 rpm 300 34 49 56 69 8 5 pv 3 4 4 4 2 yp 31 45 52 65 8 3 rpm 200 32 47 54 63 8 4 rpm 100 31 43 51 62 8 1 rpm 6 24 38 46 57 7 7 rpm 3 24 37 45 54 7 6 gel 10 s 24 38 45 57 7 2 gel 10 min 25 43 48 63 7 6 ph 9.18 9.2 4 9.19 9.38 9.4 1 api fl, cc 14.2 10. 5 8.2 7.8 6. 8 settlement no no no no n o filter cake 5/32 ” 4/3 2” 4/32” 3/32 ” 3/3 2” foam no no no no n o water torque reading 35.5 32. 0 35.8 36.0 35. 4 mud torque reading 45.9 40. 1 43.8 39.8 36. 0 lubricity factor 0.424 2 0.42 60 0.415 9 0.375 8 0.34 47 torque reduction 12. 6 4.57 13.2 9 21. 36 mud lubricity cake (kf) 0.69 0.06 9 0.073 0.06 9 0.0 61 fig. 8. fwb + mwcnt rheology with mwcnt (cof & kf *10) table 8. cof & torque and drag software reading with mwcnt +fwb rheology ------- gm 0.35 gm 0.7 gm 1.05 gm 1.75 gm lubricity factor 0.4242 0.4260 0.4159 0.3758 0.3447 torque reading 4068.67 4068.67 4018.17 3764.55 3400 fig. 9. (fwb + mwcnt) torque reading with trend line by fig. 9 mwcnt concentration of 1.75 gm is the lowest torque reading but it combined with too much high (yp=83), where the growth of yield point is come from high surface areas to the volume unite this will surge the interaction of the nanoparticles with the medium of the base fluid. yp is sensitive to mwcnt more than other nano materials due to tubular structure of mwcnt, therefor the 0.105 gm has (yp=65) where it is acceptable. also in same concentration (1.75 gm) found high gel strength comes from the high intensity of electrostatic force between nanoparticles which leads to the linkage between nanoparticles and base fluids to arrange like a rigid structure. we can also see that in low nano concentration there is no change in torque until 0.6 gm, then there is dramatically drop in torque 0.6 -1 gm to be slightly lower dropping after1 gm, so adding mwcnt more than 1.05 gm to the test sample is cost effective with relatively a little torque reduction so high amount of nanoparticles economically failed to gain our goals. in this test good results of less filtration, where the amount of filtrate was decreases a touch with increasing the concentration on nanoparticles of mwcnt. figure 9 shows also that the best linear equation is: y = -406.46x + 4177 (1) this equation ensures that mwcnt fraction reading have inversely relationship with torque, however this mixture does not match the optimum required for other mud rheology. s. y. alssafar and f.h. m. al-mahdawi / iraqi journal of chemical and petroleum engineering 20,3 (2019) 39 47 04 6conclusion and recommendation the following conclusions are captured from the research results:  no big changes in cof when we added mwcnt to polymer but there was cof increasing from 0.2 to be 0.23 (which is bad indication) but without any side effect to other mud rheology.  at high mwcnt ratio in mud type fwb we got very low ff but we lost other important mud rheology like (yp= 74, gel 0 sec= 61).  using mwcnt with polymer mud gives negative effect on torque reduction, however mwcnt is enhanced lifting cutting and hole cleaning.  high mwcnt ratio in mud type fwb gives very low cof but lost other important mud rheology like (yp= 74, gel 0 sec= 61).  the best mwcnt ratio to be really used in drilling field was 0.3% (1.05 gm in the test)[ torque drop is (4068 – 3764) ft-lb ] because if we add more a high shear rate and shear stress is required, thus more drilling risk expected.  in general, nano materials is very important enhances in mud rheology, therefor the petroleum iraqi company need to ask all drilling contractors to use these technology to drill our wells with high performance and less problems. and some points are recommended for future research:  using mwcnt with polymer mud is not recommended with respect to torque reduction, however mwcnt is enhanced lifting cutting and hole cleaning where yp & gel10 min. are increased proportionally, thus this brand of nano material is valued in fast drilling purpose particularly in vertical wells.  economically and for shallow depth using fwb with this nano material is recommended.  re-assess the stability of the same nanomaterials that we used, in hpht circumstance, with taking in consideration keeping appropriate mud rheology.  start using nanoparticle in the mud of oil fields to inspect the outcomes of stick-slip performance in wellbore conditions, in conventional well plan to clearly find out the torque reduction, when we compare that with offset well data. although mwcnt is still expensive, we used very low ratio, whereas average of 2.5 kg of mwcnt is required to mix one cubic meter of mud, that’s mean nano is cheaper and safer even from using gas oil to increase lubrication, in additional of small amount is easy to handle and cheap transportation. acknowledgement i am grateful to all of those with whom i have had the pleasure to work during this and other related projects, starting from my parents, my wife, my children, my supervisor and pdf company staff, those people help me and guide me to get ideas, solution methods, resources and analyses aids. i appreciate all my friends and wellwishers. for their words of motivation and words of comfort that come in just in time. god bless you all. nomenclatures and abbreviations mwcnt: multiwall carbon nanotube av: apparent viscosity cp. cof: coefficient of friction ff: friction factor hrs.: hours hwdp: heavy wall drill pipe idc: iraqi drilling company (rig number) bha: bottom hole assembly np: nano particles pv: plastic viscosity, cp rop: rate of penetration m/hr. fw: fresh water bentonite yp: yield point, ib/100ft 2 cp: cent poise γ: shear rate, sec-1 τ: shear stress, ib/100ft2 μp: plastic viscosity, cp references [1] v. mortazavi, “modeling of instabilities and selforganization at the frictional interface,” proquest diss. theses, vol. ph.d., no. may, 2014. [2] m. baghbanzadeh, a. rashidi, d. rashtchian, r. lotfi, and a. amrollahi, “synthesis of spherical silica/multiwall carbon nanotubes hybrid nanostructures and investigation of thermal conductivity of related nanofluids,” thermochim. acta, vol. 549, pp. 87–94, 2012. [3] f. a. & k. saad, “effect of nano-additives materials on the properties of drilling fluid,” regional annual fundamental science symposium, at johor bahru, malaysia, december 2012 [4] o. a adewuya and s. v pham, “a robust torque and drag analysis approach for well planning and drillstring design,” iadc/spe drill. conf., no. iadc/spe 39321, pp. 1–16, 1998. [5] a. zakuan, p. carigali, a. junaida, o. oil, and b. subroto, “stick slip mitigation plan to improve drilling,” spe drill. eng., 2011. [6] j. friedheim, s. young, g. de stefano, j. lee, q. guo, and m. swaco, “spe 157032 nanotechnology for oilfield applications – hype or reality ?,” no. june, pp. 12–14, 2012. https://dc.uwm.edu/cgi/viewcontent.cgi?referer=https://scholar.google.com/&httpsredir=1&article=1539&context=etd https://dc.uwm.edu/cgi/viewcontent.cgi?referer=https://scholar.google.com/&httpsredir=1&article=1539&context=etd https://dc.uwm.edu/cgi/viewcontent.cgi?referer=https://scholar.google.com/&httpsredir=1&article=1539&context=etd https://www.sciencedirect.com/science/article/abs/pii/s0040603112004339 https://www.sciencedirect.com/science/article/abs/pii/s0040603112004339 https://www.sciencedirect.com/science/article/abs/pii/s0040603112004339 https://www.sciencedirect.com/science/article/abs/pii/s0040603112004339 https://www.sciencedirect.com/science/article/abs/pii/s0040603112004339 https://www.sciencedirect.com/science/article/abs/pii/s0040603112004339 https://www.researchgate.net/publication/316558920_the_effect_of_nano-material_to_the_properties_of_drilling_fluids https://www.researchgate.net/publication/316558920_the_effect_of_nano-material_to_the_properties_of_drilling_fluids https://www.researchgate.net/publication/316558920_the_effect_of_nano-material_to_the_properties_of_drilling_fluids https://www.researchgate.net/publication/316558920_the_effect_of_nano-material_to_the_properties_of_drilling_fluids https://www.onepetro.org/conference-paper/spe-39321-ms https://www.onepetro.org/conference-paper/spe-39321-ms https://www.onepetro.org/conference-paper/spe-39321-ms https://www.onepetro.org/conference-paper/spe-39321-ms https://www.onepetro.org/conference-paper/spe-141988-ms https://www.onepetro.org/conference-paper/spe-141988-ms https://www.onepetro.org/conference-paper/spe-141988-ms https://www.onepetro.org/conference-paper/spe-157032-ms https://www.onepetro.org/conference-paper/spe-157032-ms https://www.onepetro.org/conference-paper/spe-157032-ms https://www.onepetro.org/conference-paper/spe-157032-ms s. y. alssafar and f.h. m. al-mahdawi / iraqi journal of chemical and petroleum engineering 20,3 (2019) 39 47 04 [7] g. d. alshubbar, t. n. coryell, a. atashnezhad, s. akhtarmanesh, and g. hareland, “the effect of barite nanoparticles on the friction coefficient and rheology of water based mud,” 51st us rock mech. / geomech. symp. 2017, vol. 1, 2017. [8] n. m. farhan, “effect of nanoparticles and surfactant on phase inversion of two phases”, ijcpe, vol. 18, no. 1, pp. 121-128, mar. 2017. [9] b. abdulmajeed and n. majeed, “study and analysis of concentric shell and double tube heat exchanger using tio2 nanofluid”, ijcpe, vol. 18, no. 4, pp. 1523, dec. 2017. [10] m. baghbanzadeh, a. rashidi, a. h. soleimanisalim, and d. rashtchian, “investigating the rheological properties of nanofluids of water/hybrid nanostructure of spherical silica/mwcnt,” thermochim. acta, vol. 578, pp. 53–58, 2014. [11] ofite, “ep ( extreme pressure ) and lubricity tester instruction manual,” ofi test. equipment, inc, pp. 1–34, 2015. [12] g. t. caneba, c. dutta, v. agrawal, and m. rao, “novel ultrasonic dispersion of carbon nanotubes,” j. miner. mater. charact. eng., vol. 09, no. 03, pp. 165–181, 2010. [13] a. sesis et al., “in fl uence of acoustic cavitation on the controlled ultrasonic dispersion of carbon nanotubes,” 2013. [14] e. o. nos, “elmasonic e ultrasonic cleaning units economic cleaning for all purposes • top cleaning results.” https://www.onepetro.org/conference-paper/arma-2017-0147 https://www.onepetro.org/conference-paper/arma-2017-0147 https://www.onepetro.org/conference-paper/arma-2017-0147 https://www.onepetro.org/conference-paper/arma-2017-0147 https://www.onepetro.org/conference-paper/arma-2017-0147 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/198 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/198 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/198 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/68 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/68 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/68 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/68 https://www.sciencedirect.com/science/article/abs/pii/s0040603114000069 https://www.sciencedirect.com/science/article/abs/pii/s0040603114000069 https://www.sciencedirect.com/science/article/abs/pii/s0040603114000069 https://www.sciencedirect.com/science/article/abs/pii/s0040603114000069 https://www.sciencedirect.com/science/article/abs/pii/s0040603114000069 http://www.ofite.com/doc/112-00_instructions.pdf http://www.ofite.com/doc/112-00_instructions.pdf http://www.ofite.com/doc/112-00_instructions.pdf https://www.researchgate.net/profile/colina_dutta/publication/229043259_novel_ultrasonic_dispersion_of_carbon_nanotubes/links/5509edee0cf20ed529e230ea.pdf https://www.researchgate.net/profile/colina_dutta/publication/229043259_novel_ultrasonic_dispersion_of_carbon_nanotubes/links/5509edee0cf20ed529e230ea.pdf https://www.researchgate.net/profile/colina_dutta/publication/229043259_novel_ultrasonic_dispersion_of_carbon_nanotubes/links/5509edee0cf20ed529e230ea.pdf https://www.researchgate.net/profile/colina_dutta/publication/229043259_novel_ultrasonic_dispersion_of_carbon_nanotubes/links/5509edee0cf20ed529e230ea.pdf https://pubs.acs.org/doi/abs/10.1021/jp410041y https://pubs.acs.org/doi/abs/10.1021/jp410041y https://pubs.acs.org/doi/abs/10.1021/jp410041y https://www.elmaultrasonic.com/?kw&ad=0&matchtype&adposition=none&gclid=eaiaiqobchmilru3x9ef4aivd0ttch0ecal_eaayaiaaegjgwpd_bwe https://www.elmaultrasonic.com/?kw&ad=0&matchtype&adposition=none&gclid=eaiaiqobchmilru3x9ef4aivd0ttch0ecal_eaayaiaaegjgwpd_bwe https://www.elmaultrasonic.com/?kw&ad=0&matchtype&adposition=none&gclid=eaiaiqobchmilru3x9ef4aivd0ttch0ecal_eaayaiaaegjgwpd_bwe s. y. alssafar and f.h. m. al-mahdawi / iraqi journal of chemical and petroleum engineering 20,3 (2019) 39 47 04 الى سائل الحفر لغرض التخفيف من مشكمة mwcntتقييم خاص لتقنية اضافة االلتصاق واالنزالق التي تحدث اثناء عممية الحفر سيف الدين الصفار و فالح المهداوي قسم هندسة النفط, جامعة بغداد الخالصة توقف ثم انزالق متعاقبين يحدثان بشكل ترددي في منظومة قاع البئر ظاهرة االلتصاق واالنزالق تعرف بانها اثناء عمميةالحفر نتيجة لمتباين في قيمتي جهد االحتكاك الحاصل اثناء حفر القطع الصخرية وين الجهد المسمط في المنضدةالدوارة اورأس التدوير. العامل الرئيسي لتقميل او منع حدوث هذه تقميل معامل االحتكاك بين منظومة قعر لبئر وجدار البئر يمثل الظاهرة والتي تتم عمميا عن طريق توفير اضافات لسائل الحفر تزيد من انزالقية الطين. كال التقنيات النظرية والتطبيقية تعمل سوية لتقميل تمك االهتزازات وذلك الن تخطي الحد المسموح من , احد اهم مفاتيح الحمول هو تطوير طين الحفر وكما هومعموم االهتزازات سيؤدي الى العديد من مشكال الحفر فان استخدام المواد النانوية في اطيان الحفر تعد من التقنيات الحديثة حيث نجحت في تقديم نتائج مختبرية ( fwb & polymerفي نوعين من الطين ) mwcntالطيان ذات مواصفات عالية لذا تم استخدام مادة ومن ثم تحميل النتائج مختبريًا بعدها ادخمنا نتائجمعامل االحتكاك لكل عينة في برنامج ذكي بتراكيز مختمفة يعمل تمثيل لحفر بئر عمودي ليحتسب مقدار االحتكاك المتوقع في قاع البئر. مع طين 0044ft-lbالى ft-lb 0444قي تقميل مقدار االحتكاك من mwcntنجحت المادة النانوية ft-lb( 0044 – 0404, بينما سببت ارتفاع طفيف في االحتكاك ) fresh water bentoniteالحفر نوع في حالة الطين من نوع البوليمر. , سمسمة الحفريئات النانوية, سائل الجز الدالة: مشكمة النزالق, طين الحفرالكممات iraqi journal of chemical and petroleum engineering vol.17 no.4 (december 2016) 5769 issn: 1997-4884 experimental work to study the behavior of proppant inside the hydraulic fractures and the plugging time mohammed abdul ameer and samera hamed allah petroleum engineering department, college of engineering, baghdad university abstract experiments were conducted to study the behavior of the solid particles (proppant) inside the hydraulic fracture during the formation stimulation, and study the effect of the proppant concentration on the hydraulic fracturing process, which lead to bridge and screen-out conditions inside the fractures across the fracture width that restricts fracturing fluid to flow into the hydraulic fracture. the research also studies the effect of the ratio between the fracture size and the average particles diameter “proppant", on fracture bridging. in this study two ratios were considered β= 2 and 3 ,where β = d t / d p w h e r e: d t = h yd r a u l i c f r act u r e s i z e ( w i d t h ) an d dp=average particles diameter. this work presents experimental work to study the behavior of these particles (proppant) inside the hydraulic fractures by measuring the plugging time for different particles concentration for different conditions. the experimental data recorded for different particle concentration and one flowing forces (gravity) inside the hydraulic fracture. most recorded experimental data obtained were analyzed by using spss software. introduction hydraulic fracturing is a well stimulation method where a fluid is pumped into the rock to create fractures. these fractures are intended to function as high-conductivity fluid pathways enabling increased well productivity [1]. the main goal of the hydraulic fracture treatment is to create a highly conductive flow path for hydrocarbon production. hydraulic fracturing is a technique used to stimulate the productivity of a well [2]. thus the effective permeability of a reservoir remains unchanged by this process. that mean increasing the wellbore radius and increase its productivity, because a long contact surface between the well and the reservoir is created. hydraulic fracturing is a technique in petroleum sciences. first applied of hydraulic fracturing was at 1947 (hugoton gas field, kansas) as a new technique to overcome the skin damage. hydraulic fracturing is used mainly in reservoir stimulation, control of sand production, and other purposes. it has been used to extract gas and oil from shales and other tight reserves economically. the well treatment by hydraulic fracturing job states that the fracture is approximately perpendicular to the university of baghdad college of engineering iraqi journal of chemical and petroleum engineering experimental work to study the behavior of proppant inside the hydraulic fractures and the plugging time 58 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net axis of the least stress. deepest reservoirs, the minimum stress is horizontal [3 and 9]. "a screenout is a blockage caused by bridging, accumulation, clumping or lodging of the proppant across the fracture width that restricts fluid flow into the hydraulic fracture" [4]. the stimulation treatment (hydraulic fracturing job), ends when the engineers have completed their planned pumping schedule or when a sudden rise in pressure indicating that there is a screenout has taken place [4]. there is problems, that called screenout, can occur during the fracturing job. screen-outs as defined above happen when a continued injection of fluid into the fracture requires pressure above the safe limitations of the wellbore and surface equipment. this condition happened because of high fluid leakage, high concentration of proppants, and an insufficient pad size that blocks the flow of proppants. as a result of that, pressure rapidly builds up to high value. screen-out can cause stopping a fracturing job or operation and need to clean the wellbore before resuming fracturing job [5]. during hydraulic fracturing job, engineers need to keep a constant rate for fracture fluid injection during the job. the volume injected includes the additional volume created during stimulation (hydraulic fracturing), and the fluid loss to the formation because of leakoff into the permeable wall of the fracture [6]. however, the rate of leak off during the growing hydraulic fracture tip is extremely high. therefore, it is not possible to initiate a hydraulic fracture with proppant in the fracturing fluid because the high fluid loss would cause the solid particles (proppant), at the fracture tip to reach the consistency of a dry solid, that lead to bridge and screen-out conditions. for that, using some volume of clean fluid (a pad), must be pumped before any proppant is pumped [4]. by using the down hole microseismic to indicate and control possible hazard during hydraulic fracturing job, i.e. fracture breakthrough to the over and underlying formation, screenout risk during pumping, etc. [7]; the concentrated proppant slurry cause plugging of the hydraulic fracture, and preventing additional growth of the hydraulic fracture length. additional pumping of the proppant with the fluid slurry into the formation after the screenout happen causes the hydraulic fracture to balloon. for that the fracture going to grow in width rather than length, and large concentrations of proppant per surface area will be occur in the fracture [8]. experimental work set the apparatus to measure the plugging time by using gravity force for β= 3 set the apparatus as shown in figure 1, using viscose fluid (water + 1.0% xanthan) which prepare by mixing fresh water + xanthan for about 30 min and then used, to carry and suspend the particles uniformly inside the cylinder, the particles represent the solid particles (ceramic proppant) from different sources in oil and gas industry. gravity was used to force the viscose fluid with the particles, the carrier fluid with proppant through the tube figure 1 which represent the pore throat or hydraulic fracture were called without shift as a shape name need to study. filling the cylinder with the suspension about 450 cc + 27.6 solid% by volume, open the bottom valve of the cylinder to allow flow through the fracture. during the suspension flow through http://www.iasj.net/ mohammed abdul ameer and samera hamed allah -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 59 the fracture, digital camera recorded the cumulative weight “gm “in the graduate cylinder set above digital scale, recording the cumulative weight vs. time. this type of experiment is made for 27.6 solids % by volume, for β= 3 (the ratio between the pore throat pipe “fracture size” and the average particles diameter “proppant"). set the apparatus to measure the plugging time by using gravity force for β= 3 run no. 2 the second run of experimental is the same as the first one of experiment using gravity force to force the fluid to flow through the fracture, for same particles concentration and for same β= 3 again. during the run the experiment for the second time, there is no difference between the first and second run of experiments in experiment conditions, for the above two runs of experimental, were done at the same time for same concentration and same conditions, noticed that the plugging time “sec” was different and when the experiment was repeated for the third time, also was not similar to the previous two experiments. after that repeat the experiments for about more than 10 times for each concentration to get normal distribution for the plugging time frequency. for that it is decided to repeat the experiment for about 10 times to check the plugging time if it is the same or not for each run, but noticed that the plugging time is not the same for the same conditions for each run. figures 2, 3, 4 and 5 represent the relation between the plugging time (sec) and the cumulative weight (gm), for different concentration and β= 3, figures 6, 7, 8 and 9 illustrate the normal distribution for different concentration. fig. 1: the shape of the apparatus that used to represent inside the hydraulic fracture ,fracture shape without shift http://www.iasj.net/ experimental work to study the behavior of proppant inside the hydraulic fractures and the plugging time 60 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net fig. 2: relation between the cumulative weight “gm” and the plugging time “sec”, fluid flow by gravity force for β=3, concentration 27.6 % by volume fig. 3: relation between the cumulative weight “gm” and the plugging time “sec”, fluid flow by gravity force for β=3, concentration 33.3 % by volume fig. 4: relation between the cumulative weight “gm” and the plugging time “sec”, fluid flow by gravity force for β=3, concentration 38.9 % by volume http://www.iasj.net/ mohammed abdul ameer and samera hamed allah -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 61 fig. 5: relation between the cumulative weight “gm” and the plugging time “sec”, fluid flow by gravity force for β=3, concentration 44.12 % by volume fig. 6: normal distribution chart for plugging time “sec” vs. frequency of 27.6 % particles concentration by volume, β=3 fig. 7: normal distribution chart for plugging time “sec” vs. frequency of 33.3 % particles concentration by volume, β=3 http://www.iasj.net/ experimental work to study the behavior of proppant inside the hydraulic fractures and the plugging time 62 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net fig. 8: normal distribution chart for plugging time “sec” vs. frequency of 38.9 % particles concentration by volume, β=3 fig. 9: normal distribution chart for plugging time “sec” vs. frequency of 44.1 % particles concentration by volume, β=3 set the apparatus to measure the plugging time by using gravity force for β= 2 set the apparatus as shown in figure 1, using viscose fluid (water + 1.0% xanthan ) which prepare by mixing fresh water + xanthan for about 30 min and then used, to carry and suspend the particles uniformly inside the cylinder, the particles are represent the solid particles from different sources in oil and gas industry, effectively. to force the viscose fluid with the particles to flow, gravity was used to flow through the fracture, figure 1 which represent the pore throat or hydraulic fracture. fill the cylinder with the suspension about 450 cc + solid % by volume; open the bottom valve of the cylinder to allow flow through the fracture. during the suspension flow through the fracture, digital camera was recorded the cumulative weight “gm“ in the graduate cylinder, recording the cumulative weight "gm" vs. time "sec". this type of experiment is made for different particles concentration (16.8, 21.66, 24 and 29.6) solids % by http://www.iasj.net/ mohammed abdul ameer and samera hamed allah -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 63 volume, for β= 2, figures 10, 11, 12 and 13 represent the experiments, figures 14, 15, 16 and 17 represent the normal distribution for different concentration. fig. 10: relation between the cumulative weight “gm” and the plugging time “sec”, fluid flow by gravity force for β=2, concentration 16.8 % by volume fig. 11: relation between the cumulative weight “gm” and the plugging time “sec”, fluid flow by gravity force for β=2, concentration 21.66 % by volume fig. 12: relation between the cumulative weight “gm” and the plugging time “sec”, fluid flow by gravity force for β=2, concentration 24 % by volume http://www.iasj.net/ experimental work to study the behavior of proppant inside the hydraulic fractures and the plugging time 64 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net fig. 13: relation between the cumulative weight “gm” and the plugging time “sec”, fluid flow by gravity force for β=2, concentration 29.6 % by volume fig. 14: normal distribution chart for plugging time “sec” vs. frequency of 16.8 % particles concentration by volume, β=2 fig. 15: normal distribution chart for plugging time “sec” vs. frequency of 21.66 % particles concentration by volume, β=2 http://www.iasj.net/ mohammed abdul ameer and samera hamed allah -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 65 fig. 16: normal distribution chart for plugging time “sec” vs. frequency of 24 % particles concentration by volume, β=2 fig. 17: normal distribution chart for plugging time “sec” vs. frequency of 29.6 % particles concentration by volume, β=2 material used in this work the apparatus designed to meet the fracture or pore throat by using irregular tube representing the pore throat or hydraulic fracture, and the particles represent the solid particles from different sources including water flooding, drilling fluid, perforation, work over, and fracture fluid (viscose fluid) as shown in figure 1. material for measuring plugging time by gravity force carrier fluid used was prepared form fresh water 450 cc + xanthan (1.0 %) + carbo prop ( 20/40 ), ceramic proppant, specific gravity =2.76 gm/cm 3 , as solid particles. using 1.0 % xanthan to get suitable viscosity to carry the particles through the pipe and suspend the particles uniformly inside the cylinder , as shown in figure 1, and the force to let the viscose fluid to flow was gravity. the ratio between the fracture diameter to average particles diameter was β =3 and 2. http://www.iasj.net/ experimental work to study the behavior of proppant inside the hydraulic fractures and the plugging time 66 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net experimental results plugging time by gravity force repeated for about 10 times these experiments done for the same concentration and conditions for β=3, repeated for 10 time to get the plugging time (screen out). using the spss software to get the confidence interval for plugging time for each concentration, we can get normal distribution for plugging time. figure 2 illustrates the relation between the plugging time and the cumulative weight for solid concentration 27.6% by volume particles concentration, figure 3 for 33.3% by volume particles concentration, figure 4 for 38.9% by volume particles concentration, and figure 5 for 44.1% by volume particles concentration. we can notice from these figures that for the same condition and for the same concentration the plugging time was different for each run of the experiments. the force used to force the fluid to flow was by gravity. plugging time by gravity force after the experiments were done for about 10 times, for β=3 and the same condition but different concentration and for fracture shape (without shift) figure 1, to get the plugging time by taking the average value for plugging time for different concentration. figures 2, 3, 4 and 5 illustrate the results for the fracture shape without shift for β=3 for various particles concentration by volume percent, and figures 6, 7, 8 and 9 illustrate the normal distribution for the results for β=3 for various particles concentration % by volume. for β=2 for the same fracture shape for different particles concentration we can see the results in figures 10, 11, 12 and 13 without shift represent the results for the relation between the plugging time (sec) vs cumulative weight (gm), and figures 14, 15, 16 and 17 illustrate the normal distribution for different particles concentration solid % by volume. analysis of the data data results from plugging time measurement by using gravity force and β=3 we can see in figures 2 through 5 which represent the relation between the plugging time (sec) vs cumulative weight (gm), that the plugging time represented by the sharp deflection in the curve for each of the concentrations (27.6, 33.3,38.9 and 44.12) % by volume. these plugging time correlated with the concentration % by volume and get the correlation for different concentration % by volume, as shown before, using the gravity force to allow the suspension to flow through the fracture equation 1 and figure 18, and the r 2 =0.9808, exponential relation between the concentration and the plugging time for β=2 y= 2 0 3 . 3 5 e 0 . 0 7 5 x … ( 1 ) w h er e : y= p l u g g i n g t i m e “s e c” , x =co n c en t r at i o n o f t h e p ar t i c l e s i n t h e s u s p e n s i o n % b y v o l u m e . data results for plugging time measurement by using gravity force repeated for each concentration when β=2 using the spss software to analyze the results gotten for the different runs of experiments. the experiments were repeated because of the results of the plugging times were varied when the experiments were repeated for the same concentration and same conditions, because the plugging times http://www.iasj.net/ mohammed abdul ameer and samera hamed allah -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 67 depend on the probability of the particles to be in the same place at the same time. for that the experiments were repeated for about 10 times to get normal distribution for the frequency of the time vs. the plugging times "sec", figures 6, 7, 8 and 9 represents the normal distribution of 27.6, 33.3, 38.9 and 44.12% by volume particles concentration. analyzing these data by spss getting 95% the confidence interval of plugging times table 1, we can see from table 1 that the plugging time for 27.6% by volume of particles concentration, the plugging time between 24.95 – 28.29 sec, that what we call it confidence interval of the plugging times with 95% correct and 5% error. table 1 represent the results from analyzed data, for 33.3, 38.9 and 44.12 respectively, using the spss software to get the confidence interval and the mean value of plugging time for each concentration with 95% correct and 5% error. table 1: represent confidence interval for different β and concentration % by volume plugging time (sec) conditions 95% confidence interval for mean β concentration lower bound upper bound 3 27.6 24.9567 28.2933 3 33.3 13.2721 18.3643 3 38.9 9.5041 17.3848 3 44.12 5.0021 8.9979 t h e m e an v al u e o f t h e p l u g g i n g t i m es “s e c” f r o m t h e r e s u l t s i l l u s t r a t e d i n fi g u r e 1 0 r e p r es en t s t h e r el at i o n b et w e en t h e s o l i d s co n c en t r at i o n % b y v o l u m e a n d t h e p l u g gi n g t i m e f o r β =3 . fig. 18: the relation between the concentration % by volume and the plugging time “sec”, the flow by gravity, β=3 , without shift also using the spss software to analyze the results gotten for the different runs of experiments for β=2. the experiments were repeated because of the results of the plugging times were varied when the experiments were repeated for the same concentration and same conditions, the results with the set of conditions for β=2 because the plugging times depend on the probability of the particles to be in the same place at the same time. for that the experiments were repeated also for more than 10 times to get normal distribution for the frequency vs. the plugging times "sec", figures 10 through 13 represents the relation http://www.iasj.net/ experimental work to study the behavior of proppant inside the hydraulic fractures and the plugging time 68 ijcpe vol.17 no.4 (december 2016) -available online at: www.iasj.net between the plugging time "sec" and the cumulative weight "gm" each figure represent the same condition repeated more than 10 times to get the confidence interval for the plugging time sec. figures 14, 15, 16 and 17 represents the normal distribution of 16.8, 21.66, 24 and 29.5 solids % by volume particles concentration. analyzing these data by spss getting 95% the confidence interval of plugging times table 2, we can see from table 2 that the plugging time for 16.8% by volume of particles concentration is (15.61 21.46) sec, that what we call it confidence interval of the plugging times with 95% correct and 5% error. the mean value of the plugging times “sec” from the results illustrated in figure 19 represents the relation between the concentration % by volume and the plugging time for β=2. table 2 represent the results from analyzed data, for 16.8, 21.66 , 24 and 29.6% respectively, using the spss software to get the confidence interval and the mean value of plugging time for each concentration with 95% correct and 5% error. table 2: represents the confidence interval for different β and concentration % by volume plugging time (sec) conditions 95% confidence interval for mean β concentration lower bound upper bound 2 16.8 15.6130 21.4639 2 21.66 6.7128 10.6718 2 24 6.3129 10.1871 2 29.6 2.6488 5.3512 table 3 l i s t t h e v a l u es o f r – s q u ar e, an d t h e eq u at i o n s f o r d i f f e r en t co n d i t i o n s ( p r o p p an t co n c en t r at i o n , p l u g g i n g t i m e ( s ec ) an d β ) . fig. 19: the relation between the concentration % by volume and the plugging time “sec”, the flow by gravity, β=2 , without shift t a b l e 3 : r e p r e s e n t t h e v a l u e s o f r – s q u a r e a n d t h e e q u a t i o n e x p e r i m e n t s n o . f r a c t u r e s h a p e β v a l u e r 2 c o r r e l a t i o n f i g u r e n o . 1 w i t h o u t s h i f t 3 0 . 9 8 0 8 y = 2 0 3 . 3 5 e 0 . 0 7 5 x 1 8 2 w i t h o u t s h i f t 2 0 . 9 9 4 7 y = 1 6 3 . 3 8 e 0 . 1 2 4 x 1 9 http://www.iasj.net/ mohammed abdul ameer and samera hamed allah -available online at: www.iasj.net ijcpe vol.17 no.4 (december 2016) 69 c o n cl u s i o n the two figures 18 and 19 above, illustrates that the region below the curve line that indicate the conditions for non-screen out whereas the region above the curve indicate the screen out region, because of that fracture engineer need to avoid the conditions above the curves and make an optimization between the fracture width, proppant concentration and the proppant size for success fracture job. references 1. yongping li, yonghui wang, xingsheng cheng, mingguang che, langfang branch of riped, petrochina; fuxiang "propped fracturing in high temperature deep carbonate formation ", spe 118858 copy right 2009, society of petroleum engineers. 2. gidley, j.l., john l. gidley and assocs. inc "a method for correcting dimensionless fracture conductivity for non-darcy flow effects" spe production engineering, volume 6, number 4, november 1991. 3. shah, s. “pe – 5423 advanced stimulation class notes”. mpge, university of oklahoma, fall 2008, norman, ok. 4. richard nolen-hoeksema: oilfield review summer 2013: 25, no. 2. copyright © 2013 schlumberger. 5. kristian brekke, bellaire, tx (u s), system and method for detecting screen-out usinga fracturing valve for mitigation, united states, patent application publication, pub. date: mar. 27, 2014. 6. h. gu and e. siebrits. “effect of formation modulus contrast on hydraulic fracture height containment” spe paper prepared for presentation at the 2006 spe international oil and gas conference and exhibition in china, beijing, 5-7 december 2006. 7. a. konopelko, and v. sukovatyy, gazprom neft orenburg cjsc; a mitin and a rubtsova, weatherford llc, microseismic monitoring of multistage hydraulic fracturing in complex reservoir of the volgourals region of russia, spe – 176710 – ms 2015. 8. inventors: curtis l. boney, houston, tx (us); dean m. willberg, sugar land, tx, methods and fluid compositions designed to cause tip screenouts, pub. n0.2 us 2003/0062160 a1, date: apr. 3, 2003. 9. bryant w, hainey, richardson; xiaowei weng, plano, both of tex. "hydraulic fracturing from deviated wells", united states patent patent number: 5,497,831 date of patent: mar. 12, 1996. http://www.iasj.net/ available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.23 no.1 (march 2022) 9 – 14 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: abdullah a. hussain , email: abdullah.hussein@uobasrah.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. the conductivity of ac, loss tangent, and relative permittivity for composites of pvc paste/graphite electrode waste abdullah a. hussain a , forat yasir aljaberi b and feras n. hasoon c a department of material science, polymer research center, university of basrah, basrah, iraq b department of chemical engineering, college of engineering, al-muthanna university, al-muthanna, iraq c department of electrical and communication engineering, national university of science and technology, muscat oman. abstract the behavior of ac conductivity (σac), loss tangent (tan δ), and relative permittivity (ε′) for composites of pvc-p/graphite electrode waste (gew) was investigated, and a qualitative explanation was provided as a function of pvc-p weight fractions (0, 5, 10, 15, 20, and 25) wt. percent, temperature (30-90) °c, and frequency (100hz-2mhz). the behaviors of the composites' ac. conductivity and impedance as a frequency function and temperature have been examined. the permittivity was shown to rise with increasing temperature (tg). the relative permittivity increased as the gew filler concentration increased and was highest in the lowfrequency range; nevertheless decreased as the frequency increased. keywords: polyvinyl chloride paste, ac conductivity, graphite electrode waste, permittivity, composite. received on 01/02/2022, accepted on 10/03/2022, published on 30/03/2022 https://doi.org/10.31699/ijcpe.2022.1.2 1introduction polymer and organic filler composites have been effective in the electrical and electronic industries. the electrical properties of these heterogeneous systems are influenced by the size, volume fraction, conductivity of the filler, shape, the filler's adherence to the polymer, and the processing step. composites like this have the advantage of being ab le to be built to have improved and compatible qualities that separate materials might not have [1-4]. fillers, for instance, diamond, silicon carbide, alumina, boron nitride, aluminum nitride, beryllium oxide, and fused sio2, are utilized to make both electrically insulating and thermally conducting composites of polymer-matrix [5-8]. to increase electrical and thermal properties, carbon black, metallic fillers, and graphite are utilized [8-10]. the dielectric permittivity of non-conductive fillers is increased by polarization between the two surfaces (maxwell-wagner-sillars polarization). due to interfacial polarization, nonconductive fillers increase dielectric permittivity (maxwell-wagner-sillars polarization). to properly use composites, it is necessary to be able to evenly distribute fillers throughout the material [11]. exfoliating graphite intercalation compounds results in expanded graphite with a high aspect ratio and decent electrical conductivity by rapidly heating them in a microwave or furnace. graphite electrode waste from electric arc furnaces can be used in place of manufactured graphite to reinforce carbon composites. the industry has made extensive use of antistatic, electromagnetic shielding, and electronic technology materials [12, 13]. composite materials have been employed in electronic technology to create a device with superior energy storage systems and electromagnetic [14] or energy storage technologies based on electrochemistry [15]. in this work, the dielectric characteristics of (pvc-p as a matrix and gew powder as a filler) the properties of composites were investigated as a function of the filler weight percentage (5, 10, 15, 20, and 25 wt. percent), temperature (30-120 °c) and frequency (100 hz-2 mhz). impedance and ac conductivity were also investigated. 2experiment method and materials 2.1. materials as polymer matrix for the composites, commercial (lichide) pvc paste 717-21 heavy duty-clear was supplied by swan trading-c h i n a (l.l.c.) (as received from the market), with permittivity (ε'= 3.2), volume resistivity ~ 5.5×10 15 ohm/cm, and density=1.43 gm/cm 3 [15]. the iron and steel factory's gew powder, with a particle size of ~ 45nm, is utilized as an additive. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:abdullah.hussein@uobasrah.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2022.1.2 abdullah a. hussain et al./ iraqi journal of chemical and petroleum engineering 23,1 (2022) 9 14 10 2.2. preparation of samples the gew powders were incorporated into the pvc-p in varying % of weight (5, 10, 15, 20, and 25 wt. percent) and adequately mixed at approximately 65°c for 7 minutes to provide decent filler dispersion and a homogeneous composite. then, the mixture was decanted over clean al substrates as a thick layer. the primary curing occurred 24 hours at room temperature, after that a 2-hour post-cure at 120°c. on the casted composites' upper surface, thin-film aluminum electrodes in the shape of a circular disk with a diameter of 6 mm were vacuum deposited and 10 -6 torr. finally, an al/pvcp: gew/al sandwich was investigated as depicted in fig. 1 fig. 1. schematic diagram of the fabrication dielectric device 2.3. characterization and measurement at 120hz and 1 khz, the sample capacitance and loss tangent (tan δ) of composites were determined using a fluke pm6303a-kelvin. 3results and discussion dielectric relaxation strength, energy loss, and electric permittivity are essential factors in material science because to the fact that they are utilized to determine whether a material is suitable for a certain application. this experiment was aimed to investigate the pvcp/gew composite's behavior and dielectric characteristics. the frequency dependence of dielectric characteristics is shown in fig. 2, at room temperature, the fluctuation of tan of gew filled pvc-p composites is a function of the range's frequency (120 hz 2 mhz). fig. 2. the loss tangent of the composite pvc-p/gew as a function of frequency for all frequency ranges studied, tan δ rises as filler content increases. the increase in tan δ with increased filler content could be due to induced polarization caused by the applied electric field at the polar ends of the particle. the charge carriers are then transported efficiently around the interface and converted the conducting [16]. this will result in a permittivity greater than that of the particle. the presence of a relaxation peak at roughly 100 khz, indicating changes in the polymer molecular structure, is intriguing. the relaxing of the polymer happens when gew interrupts the original crystallization process of pvc-p, resulting in more free volume and more flaws due to the poor interface [17]. the fluctuation of tan δ as a function of temperature in the range 30-90 c for pure pvc-p and pvc-p/gew composites at a constant frequency (1khz) is illustrated in fig. 3 (with different filler concentrations). tan δ is known to rise in general, when the filler amount or temperature rises. increased filler content causes an increase in tan, which is connected to interfacial polarization, whereas increased temperature causes an increase in segmental mobility and ionic conductivity. due to the molecule's thermal dissociation, the degree of dipole orientation increases and ionic conduction increases, since temperature (and thus viscosity) affect the number of losses due to dipole friction [17-21]. the following formula was utilized to quantify the ac electrical characteristics of a composite material sample. ε*(ω) is the frequency dependence complex dielectric permittivity [19-21]. ε*(ω) = ε'(ω) ε"(ω) (1) where: ε'(ω) and ε"(ω) are the real and imaginary components of complex dielectric permittivity. fig. 3. the loss tangent of the pvc-p/gew composite as a function of temperature-dependent abdullah a. hussain et al./ iraqi journal of chemical and petroleum engineering 23,1 (2022) 9 14 11 fig. 4 shows pvc-p/gew at room temperature, as a function of frequency. electrical conductivity (σ) is inversely proportional to dielectric constant variation with frequency, as expected. the ε' has a value that is large at low frequencies and diminishes exponentially as the frequency increases. the interfacial polarization process and the polarization caused by segmental mobility in the polymer, which is more effective at low frequency and high temperature, respectively, are attributed to high values ε′ in the lowfrequency range [18-22]. at high frequencies, the dipoles that cause these two polarizations have less time to align themselves with the alternating field's direction. fig. 4. frequency-dependence of the dielectric permittivity of pvc-p/gew composite fig. 5 illustrates the dielectric permittivity (ε′) of the pvc-p/gew composite for varied filler concentrations as a function of temperature in the range of 30-90°c. for comparison, pure pvc-p was presented in the illustration. it is demonstrable that ε′ grows with rising temperature in all circumstances, up to a point where a further rise in temperature causes the ε′ value to decrease. because the filler permittivity does not change significantly with temperature, the composites' dielectric response may be attributed to two factors: first, the polymer's segmental mobility, which rises with temperature; this mechanism should enhance the dielectric constant at high temperatures due to the increased freedom of movement of the dipole molecular chains inside the polymer [23], and second, the dielectric response of the composites. second, the heat expansion of the polymer and filer causes the breakage of connections between filler particles; this mechanism should lower the dielectric constant [23-26]. the structure's orientation within the material also affects dielectric characteristics. from the measured loss tangent and capacitance, permittivity dielectric loss can be calculated as follows [20-23]: vθ =vt sin (π-φ) (2) tan δ=(vt 2 -vθ 2 ) 1/2 /vθ (3) fig. 5. the real dielectric permittivity of the pvc-p/gew composite as a function of temperature-dependent fig. 6 shows the fluctuation of ac conductivity (σac) at room temperature with a frequency from 120hz to 2mhz for pure pvc-p and pvc-p/gew of composites. at room temperature, it is clear that σac increases as the frequency increase. this is typical behavior for dielectric material, which may be attributed to the insulating phase of (pvcp), which forms the boundaries between the conductive particles of gew filler. these boundaries are more active to prevent hopping and tunneling conduction between the insulated conductive particles. temperature dependence of ac conductivity (σac) in the range (30 – 90 o c) at constant electric field frequency at 1khz of the pure pvcp and pvc-p/gew of composites shown in fig. 7. it was noticed that increase in ac conductivity with temperature is due to contributed by free charges available in the composite system. it was also found that, at a higher temperature, high mobility of free charges make them more frequency independent conductivity[18,19,26]. fig. 6. ac conductivity of pvc-p/gew composite as a function of frequency-dependent abdullah a. hussain et al./ iraqi journal of chemical and petroleum engineering 23,1 (2022) 9 14 12 fig. 7. ac conductivity of the pvc-p/gew composite as a function of temperature-dependent the ac conductivity (a.c) was computed using the following formula: ε'(ω) = c d / εo a (4) ε"(ω) = ε' tan δ (5) where: d is the distance between two electrodes when they are separated, a is the electrode's area, εo is the free space's permittivity, (εo=8.85×10 -12 f/m). σac = εo ω ε" (6) where: ω = 2πυ is the angular frequency. the following formula uses to calculate the complex impedance (z * ) z * =z+iz (7) where: z is the real and iz is the imaginary impedance portions, correspondingly. the fluctuation of impedance z with frequency for pvc-p: gew composites is shown in fig. 8. fig. 8. temperature dependence of the frequency for pvc-p/gew composite the phase angle was always negative, indicating that the composites were capacitive and could be modeled as a series of parallel rc networks (lumped circuits). with the rising frequency and gew concentration, impedance values drop. the process of protonic migration and contaminants contained in gew filler is responsible for the observed decrease in impedance as gew concentration increases. this movement results in increased electrical conductivity in filled composites [21]. the impedance decreases exponentially with increasing frequency for all filler volume fractions, but the decline is larger for composites with a high filler content [22]. the temperature dependence of impedance z of pvc-p: gew composites are shown in fig. 9. fig. 9. pvc-p/gew composite impedance frequency dependency as the filler volume fraction increases due to greater interfacial polarization and as the temperature rises, there is a noticeable drop in z. for all situations in which filler was added, the impedance z reduces as the temperature rises, with clear dips near (90 o c) temperature. as the temperature increased, the mobility of segmental molecules increased as well. could explain the drop in z. the dips could be related to the temperature zone of the glass transition where segmental mobility is higher. as a result, these dips may refer to the glass transition temperatures of all composite materials. 4conclusions electric permittivity, dielectric loss, and loss tangent all raise as the graphite electrode waste filler concentration or temperature is increased, which has been attributed to interfacial polarization and segmental mobility of the polymer molecules, respectively. electric permittivity decreases with increasing frequency due to the difficulty of interfacial and segmental mobility polarizations to retain orientation in the alternating field's direction. the composite's impedance z decreases as the frequency, volume of filler, and temperature increase. abdullah a. hussain et al./ iraqi journal of chemical and petroleum engineering 23,1 (2022) 9 14 13 acknowledgements the department of material science, polymer research centre, and the department of physics, college of education for pure science, university of basrah, basrah, iraq, supported this research. references [1] jan kruzelak, andrea kvasnicakova, klaudia hlozekova, and ivan hudec, “progress in polymers and polymer composites used as efficient materials for emi shielding”, nanoscale advances., 2021, 3, 123-172. [2] yulia perets, lyudmila aleksandrovych, mykola melnychenko, oleksandra lazarenko, lyudmila vovchenko, and lyudmila matzui,” the electrical properties of hybrid composites based on multiwall carbon nanotubes with graphite nanoplatelets”,nanoscale research letters, 2017, 12,1-10. [3] urszula szeluga, bogumiła kumanek, barbara trzebicka, synergy in hybrid polymer/nanocarbon composites. a review, composites part a: applied science and manufacturing, 2015,73, 204-231 [4] nitin mehra,. liwen mu, tuo ji and jiahua zhu, "thermal conduction in polymer composites." polymer-based multifunctional nanocomposites and their applications. elsevier, 2019. 77-110 [5] xingyi huang, pingkai jiang, toshikatsu tanaka, a review of dielectric polymer composites with high thermal conductivity, ieee electrical insulation magazine 2011, 27, 8-16. [6] chen pan, kaichang kou, yu zhang, ziyu li, “enhanced through-plane thermal conductivity of ptfe composites with hybrid fillers of hexagonal boron nitride platelets and aluminum nitride particles”, composites part b engineering, 2018, 153,1-8 [7] lee, henry and k. neville, handbook of epoxy resins. 1967, 5-13. [8] lona plesa, petru v. notingher, sandra schlögl, christof sumereder and michael muhr, properties of polymer composites used in high-voltage applications, review polymers, 2016, 8,173. [9] weidenfeller, bernd, michael höfer, and frank schilling. "thermal and electrical properties of magnetite filled polymers." composites part a: applied science and manufacturing, 2002, 33,1041-1053. [10] ye p. mamunya, v. v. davydenko, p. pissis, and e. v. lebedev. "electrical and thermal conductivity of polymers filled with metal powders." european polymer journal, 2002, 38, 1887-1897. [11] xiaodong xia , jiahao, yang wang, zheng zhong, george j weng "theory of electrical conductivity and dielectric permittivity of highly aligned graphene-based nanocomposites." journal of physics: condensed matter, ,2017,29, 205702. [12] waleed a. hussain, abdullah a. hussein, jabar m. khalaf, ali h. al-mowali, abdullwahab a. sultan, dielectric properties and a.c. conductivity of epoxy/alumina silicate ngk composites, advances in chemical engineering and science, 2015, 5, 282-289 [13] beata tryba, antoni w morawski, michio inagaki, preparation of exfoliated graphite by microwave irradiation, september, carbon, 2005, 43,2417-2419. [14] babaevsky, p.g., kozlov, n.a., churilo, i.v., and slagoda, v.v, influence of simulated and natural space environment factors on dielectric properties of epoxyamine polymers and polymer-based composite materials, cosmic research, 2005, 43, 25-33. [15] toshikatsu tanaka, dielectric nanocomposites with insulating properties, ieee transactions on dielectrics and electrical insulation, 2005, 12, 914-928. [16] singha, santanu and m. jeo thomas, m.j.permittivity and tan delta characteristics of epoxy nanocomposites in the frequency range of 1mhz1ghz, ieee transactionson dielectrics and electrical insulation, 2008,15,2-11. [17] vishal singh, a. r. kulkarni, and t. r. rama mohan, dielectric properties of aluminum-epoxy composites, journal of applied polymer science,2003, 90,3602-3608. [18] kim, chy-hyung, and jae-sup shin. "dielectric relaxation of siloxane-epoxy copolymers." bulletin of the korean chemical society,2002,23,413-416. [19] ramajo, l., miriam susana castro, and maria marta reboredo. "effect of silane as coupling agent on the dielectric properties of batio3-epoxy composites." composites part a: applied science and manufacturing, 2007, 38, 1852-1859. [20] hyun, j.g., lee, s. and paik, k.w, frequency and temperature dependence of dielectric constant of epoxy/ batio3 composite, electronic component and technology conference, 2005, 1241-1247. [21] muhammed, a., athar, j. and tasneem, z. r, dielectric properties of industrial polymer composite materials. turkish journal of physics, 2005, 29, 355-362. [22] hadik, n., a. outzourhit, a. elmansouri, a. abouelaoualim, a. oueriagli, and e. l. ameziane. "dielectric behavior of ceramic (bst)/epoxy thick films." active and passive electronic components, 2009. [23] saq’an, s.a., ayesh, a.s., zihlif, a.m., martuscelli, e. and ragosta, g., physical properties of polystyrene/alum composites. polymer testing,2004, 23,739-745. [24] cheng, k.c., lin, c.m., wang, s.f., lin, s.-t. and yang, c.f, dielectric properties of epoxy resin-barium titanate composites at high frequency. materials letters,2007, 61, 757-760. [25] medalia, a.i., electrical conductionin carbon black composites. rubber chemistry and technology, 1986, 59,432-454. [26] abdullah a . hussein, and hussain, w.a., dielectric properties of epoxy/batio 3 composites. journal of basrah researches, sciences, 2010, 36,1-7. https://pubs.rsc.org/en/content/articlehtml/2021/na/d0na00760a https://pubs.rsc.org/en/content/articlehtml/2021/na/d0na00760a https://pubs.rsc.org/en/content/articlehtml/2021/na/d0na00760a https://pubs.rsc.org/en/content/articlehtml/2021/na/d0na00760a https://link.springer.com/article/10.1186/s11671-017-2168-8 https://link.springer.com/article/10.1186/s11671-017-2168-8 https://link.springer.com/article/10.1186/s11671-017-2168-8 https://link.springer.com/article/10.1186/s11671-017-2168-8 https://link.springer.com/article/10.1186/s11671-017-2168-8 https://link.springer.com/article/10.1186/s11671-017-2168-8 https://www.sciencedirect.com/science/article/abs/pii/s1359835x15000731 https://www.sciencedirect.com/science/article/abs/pii/s1359835x15000731 https://www.sciencedirect.com/science/article/abs/pii/s1359835x15000731 https://www.sciencedirect.com/science/article/abs/pii/s1359835x15000731 https://www.sciencedirect.com/science/article/pii/b9780128150672000032 https://www.sciencedirect.com/science/article/pii/b9780128150672000032 https://www.sciencedirect.com/science/article/pii/b9780128150672000032 https://www.sciencedirect.com/science/article/pii/b9780128150672000032 https://www.sciencedirect.com/science/article/pii/b9780128150672000032 https://ieeexplore.ieee.org/abstract/document/5954064 https://ieeexplore.ieee.org/abstract/document/5954064 https://ieeexplore.ieee.org/abstract/document/5954064 https://ieeexplore.ieee.org/abstract/document/5954064 https://www.sciencedirect.com/science/article/abs/pii/s1359836818310953 https://www.sciencedirect.com/science/article/abs/pii/s1359836818310953 https://www.sciencedirect.com/science/article/abs/pii/s1359836818310953 https://www.sciencedirect.com/science/article/abs/pii/s1359836818310953 https://www.sciencedirect.com/science/article/abs/pii/s1359836818310953 https://www.mdpi.com/2073-4360/8/5/173 https://www.mdpi.com/2073-4360/8/5/173 https://www.mdpi.com/2073-4360/8/5/173 https://www.mdpi.com/2073-4360/8/5/173 https://www.sciencedirect.com/science/article/abs/pii/s1359835x02000854 https://www.sciencedirect.com/science/article/abs/pii/s1359835x02000854 https://www.sciencedirect.com/science/article/abs/pii/s1359835x02000854 https://www.sciencedirect.com/science/article/abs/pii/s1359835x02000854 https://www.sciencedirect.com/science/article/abs/pii/s0014305702000642 https://www.sciencedirect.com/science/article/abs/pii/s0014305702000642 https://www.sciencedirect.com/science/article/abs/pii/s0014305702000642 https://www.sciencedirect.com/science/article/abs/pii/s0014305702000642 https://iopscience.iop.org/article/10.1088/1361-648x/aa68ec/meta https://iopscience.iop.org/article/10.1088/1361-648x/aa68ec/meta https://iopscience.iop.org/article/10.1088/1361-648x/aa68ec/meta https://iopscience.iop.org/article/10.1088/1361-648x/aa68ec/meta https://iopscience.iop.org/article/10.1088/1361-648x/aa68ec/meta https://www.scirp.org/html/5-3700585_57578.htm?pagespeed=noscript https://www.scirp.org/html/5-3700585_57578.htm?pagespeed=noscript https://www.scirp.org/html/5-3700585_57578.htm?pagespeed=noscript https://www.scirp.org/html/5-3700585_57578.htm?pagespeed=noscript https://www.scirp.org/html/5-3700585_57578.htm?pagespeed=noscript https://www.researchgate.net/profile/beata-tryba/publication/244576589_studies_of_exfoliated_graphite_eg_for_heavy_oil_sorption/links/5536316d0cf20ea35f1127f5/studies-of-exfoliated-graphite-eg-for-heavy-oil-sorption.pdf https://www.researchgate.net/profile/beata-tryba/publication/244576589_studies_of_exfoliated_graphite_eg_for_heavy_oil_sorption/links/5536316d0cf20ea35f1127f5/studies-of-exfoliated-graphite-eg-for-heavy-oil-sorption.pdf https://www.researchgate.net/profile/beata-tryba/publication/244576589_studies_of_exfoliated_graphite_eg_for_heavy_oil_sorption/links/5536316d0cf20ea35f1127f5/studies-of-exfoliated-graphite-eg-for-heavy-oil-sorption.pdf https://link.springer.com/article/10.1007/s10604-005-0016-6 https://link.springer.com/article/10.1007/s10604-005-0016-6 https://link.springer.com/article/10.1007/s10604-005-0016-6 https://link.springer.com/article/10.1007/s10604-005-0016-6 https://link.springer.com/article/10.1007/s10604-005-0016-6 https://ieeexplore.ieee.org/abstract/document/1522186 https://ieeexplore.ieee.org/abstract/document/1522186 https://ieeexplore.ieee.org/abstract/document/1522186 https://ieeexplore.ieee.org/abstract/document/4446731/ https://ieeexplore.ieee.org/abstract/document/4446731/ https://ieeexplore.ieee.org/abstract/document/4446731/ https://ieeexplore.ieee.org/abstract/document/4446731/ https://ieeexplore.ieee.org/abstract/document/4446731/ https://onlinelibrary.wiley.com/doi/abs/10.1002/app.13085 https://onlinelibrary.wiley.com/doi/abs/10.1002/app.13085 https://onlinelibrary.wiley.com/doi/abs/10.1002/app.13085 https://onlinelibrary.wiley.com/doi/abs/10.1002/app.13085 https://www.koreascience.or.kr/article/jako200202727363513.page https://www.koreascience.or.kr/article/jako200202727363513.page https://www.koreascience.or.kr/article/jako200202727363513.page https://www.sciencedirect.com/science/article/abs/pii/s1359835x07000681 https://www.sciencedirect.com/science/article/abs/pii/s1359835x07000681 https://www.sciencedirect.com/science/article/abs/pii/s1359835x07000681 https://www.sciencedirect.com/science/article/abs/pii/s1359835x07000681 https://www.sciencedirect.com/science/article/abs/pii/s1359835x07000681 https://ieeexplore.ieee.org/abstract/document/1441429 https://ieeexplore.ieee.org/abstract/document/1441429 https://ieeexplore.ieee.org/abstract/document/1441429 https://ieeexplore.ieee.org/abstract/document/1441429 https://journals.tubitak.gov.tr/physics/abstract.htm?id=7956 https://journals.tubitak.gov.tr/physics/abstract.htm?id=7956 https://journals.tubitak.gov.tr/physics/abstract.htm?id=7956 https://www.hindawi.com/journals/apec/2009/437130/ https://www.hindawi.com/journals/apec/2009/437130/ https://www.hindawi.com/journals/apec/2009/437130/ https://www.hindawi.com/journals/apec/2009/437130/ https://www.sciencedirect.com/science/article/abs/pii/s0142941804000546 https://www.sciencedirect.com/science/article/abs/pii/s0142941804000546 https://www.sciencedirect.com/science/article/abs/pii/s0142941804000546 https://www.sciencedirect.com/science/article/abs/pii/s0142941804000546 https://www.sciencedirect.com/science/article/abs/pii/s0167577x06006641 https://www.sciencedirect.com/science/article/abs/pii/s0167577x06006641 https://www.sciencedirect.com/science/article/abs/pii/s0167577x06006641 https://www.sciencedirect.com/science/article/abs/pii/s0167577x06006641 https://meridian.allenpress.com/rct/article-abstract/59/3/432/91878/electrical-conduction-in-carbon-black-composites https://meridian.allenpress.com/rct/article-abstract/59/3/432/91878/electrical-conduction-in-carbon-black-composites https://meridian.allenpress.com/rct/article-abstract/59/3/432/91878/electrical-conduction-in-carbon-black-composites https://www.researchgate.net/profile/abdullah-hussein/publication/281639970_dielectric_properties_of_epoxy_batio_3_composites/links/55f1c86308aef559dc492e46/dielectric-properties-of-epoxy-batio-3-composites.pdf https://www.researchgate.net/profile/abdullah-hussein/publication/281639970_dielectric_properties_of_epoxy_batio_3_composites/links/55f1c86308aef559dc492e46/dielectric-properties-of-epoxy-batio-3-composites.pdf https://www.researchgate.net/profile/abdullah-hussein/publication/281639970_dielectric_properties_of_epoxy_batio_3_composites/links/55f1c86308aef559dc492e46/dielectric-properties-of-epoxy-batio-3-composites.pdf abdullah a. hussain et al./ iraqi journal of chemical and petroleum engineering 23,1 (2022) 9 14 14 دراسة التوصيلية الكهربائية المتناوبة وزاوية الفقد والسماحية الكهربائية لمتراكبات البولي الالصق / مخلفات اقطاب الكرافيتفينيل كلورايد 3فراس ناظم حسونو 2فرات ياسر الجابريو 1عبداهلل عباس حسين العراق-جامعة البصرة 1 العراق-جامعة المثنى 2 سلطنة عمان-الجامعة الوطنية للعلوم والتكنولوجيا 3 الخالصة ( لمتراكبات ′ε، والسماحية النسبية ) (tan δ( ، وزاوية الفقد )acتم فحص سلوك التوصيلية المتناوبة ) ( بحسب pvc-p( ، وتم تقديم تفسير نوعي كدالة لـ )gew/ مخلفات اقطاب الجرافيت ) pvc-pبوليمر 2-هرتز 100( درجة مئوية والتردد )90-30( ودرجة الحرارة )25 و 20, 15, 10, 5, 0النسب الوزنية ) يلية المتناوبة والمقاومة كدالة للتردد ودرجة الحرارة. لوحظ التوص acميجاهرتز(.تم فحص سلوك المركبات ' وكان أعلى gew(. زادت السماحية النسبية مع زيادة تركيز حشو tgازدياد السماحية مع زيادة درجة الحرارة ) في نطاق التردد المنخفض ؛ ومع ذلك انخفض مع زيادة التردد. ، بقايا قطب الجرافيت ، السماحية ، المركب acالكلمات الدالة: معجون بولي فينيل كلوريد ، موصلية available online at https://ijcpe.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.19 no.2 (june 2018) 15 – 20 issn: 1997-4884 corresponding authors: mohammed saleh aljawad, email: mohaljawad@yahoo.com, abdullah abdulhasan ali, email: spcbasrah@yahoo.com, marwah dhahir abdulkhadim, email: ma88_t@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial-noderivatives 4.0 international license comparison of petrophysical properties measurement methods in sandston rocks mohammed saleh aljawad a , abdullah abdulhasan ali b and marwah dhahir abdulkhadim c a petroleum technology department / university of technology b south oil company / geology department c petroleum technology department / university of technology abstract this paper displays a survey about the laboratory routine core analysis study on ten sandstone core samples taken from zubair reservoir/west quarna oil field. the petrophysical properties of rock as porosity, permeability, grain's size, roundness and sorting, type of mineral and volumes of shales inside the samples were tested by many apparatus in the petroleum technology department/ university of technology such as ofite blp-530 gas porosimeter, perg-200 tm gas permeameter and liquid permeameter, geospec2 apparatus (nmr method), scanning electron microscopy (sem) and ofite spectral gamma ray logger apparatus. by comparing all the results of porosity and permeability measured by these instruments, it is clear a significant variation in the values with the depth within same formation. the porosity by gas, liquid and nmr are varied (15.4 35.9) %, (4.6 22.3) % and (2.4 13.5) % respectively, while the permeability by gas, liquid and nmr were altered (0 512) md, (0-139.6) md and (1.577 x10 -6 – 492) md respectively. keywords: porosity, permeability, routine core analysis accepted on 27/2/2017 1introduction routine core analysis is essential in the petroleum industry. it determines the petrophysical properties of samples that improved from the surface of revelation by the geologic data. the core assessing involve lithology as carbonates, sandstones shales and coal etc. the samples usually are recovered in the vertical or horizontal direction with respect to the surface ‎[1]. the cores are necessary for identification the system of pores among the reservoir unit and that will improves the ability to predict the performance of reservoir and therefore this helps in selection the methods to increase the profit of hydrocarbon recovery to the maximum value. the core analysis in the early life was an art and from such initiation this art developed using the modern development in empirical methods of physical and chemical analyses. nowadays, different tools as nmr analysis (nuclear magnetic resonance), sem (scanning electron microscopy), mass spectrometry, high frequently phase analysis; gas chromatography, etc. are used in the core testing ‎ [2]. 2core preparation ten sandstone core samples were taken from well number (2) of zubair formation (west qurna oil field) at depths (3219-3266) meters ‎[3]. by using each of rock well (cutting device) and grinder apparatus, the plugs were cut in the horizontal direction which was parallel to the bedding plane in a special dimensions length about 2.54 cm (1 inch) and diameter about 3.8 cm (1.5 inch). 3core measurements 3.1. routine core analysis a. porosity measurement each of the ofite blp-530 gas porosimeter and geospec2 equipment were used to determine effective porosity for samples. all samples were evacuated from air by vacuum equipment and then the effective porosity was measured first by the porosimeter. the porosimeter measurement is based on boyle's law (p1v1 = p2v2) the second equipment that was used to measure the effective porosity (e) and (t) is geospec2 fig. 1. the principle of analyses the rock core is nmr (nuclear magnetic resonance). (nmr) is commonly applied in well logging measurements and for routine laboratory core analysis. the petrophysical properties of the rock core that can be evaluated by the nmr are porosity, permeability, pore size distribution, producible fluid type, free fluid index and oil viscosity. m. s. aljawad, a. a. ali and m. d. abdulkhadim / iraqi journal of chemical and petroleum engineering91,2 (2018) 15-20 61 the nmr information gained for rock reflects electrical signal distribution created by hydrogen protons found in the fluids that gratify the rock. another device used to measure effective porosity was the vacuum pump, by liquid saturation method. the fresh water was used to cool and clean cutting edge, then the fluids in the samples were extracted using soxhelt extractor. toluene (c7h8), benzene (c6h6) and methanol (ch3oh) were used to remove the residual fluids and salts. after that, the oven was used for drying the samples at temperature (230 c˚). fig. 1. geospec2 apparatus b. permeability measurement absolute permeability of the prepared samples was measured using core lab perg-200 tm gas permeameter apparatus before saturation the samples with the fresh water. then the permeability was calculated by using the liquid permeameter and geospec2 apparatuses for these samples after saturation process. the results of air permeability were corrected for gas slippage employing klinkenberg correction. darcy's law for gas and liquid was used to calculate permeability. 3.2. mineralogical analysis minerals inside the samples were specified by ofite spectral gamma ray logger fig. 2 and scanning electron microscopy. the device (figure 2) determines the radiation quantity that sends out from a core sample and then computes the quantity of each of the elements. the quantities of each of these elements are counted. ten thin sections ''slides'' fig. 3 from core samples were go run in the university of baghdad, department of geology and were checked by microscope to detect the mineral components, heavy minerals types, diagentic process and its influence on structure of rocks and mineral synthesis, in addition to study the changes in lithology to define formation depositional environment in order to form an obvious image about reservoir behavior through the enhanced recovery processes. according to the microscope examination for slides and wentworth classification ‎[4], the average grains' size, shape and roundness and sorting degree were determined. grain's roundness is a significant property for sample characteristic due to its represents a guide to the substantial geological standards (porosity and permeability) ‎[5]. degree of sorting reflects the nature of depositional environment. fig. 2. ofite spectral gamma ray logger fig. 3. thin sections for all core samples 4experimental work before beginning the experiments all pressure gauges, pumps, and all instruments were calibrated. the experiments were implemented as following: 4.1. measurement the gas porosity length and diameter of plugs were measured in order to calculate the bulk volume (vb) and then the pore volume (vp). m. s. aljawad, a. a. ali and m. d. abdulkhadim / iraqi journal of chemical and petroleum engineering91,2 (2018) 15-20 61 after that the plugs were placed into the core holder of gas porosimeter to calculate inlet and outlet pressure and volume of gas inside the core holder to be then applied first in boyle's law (p1v1 = p2v2) and after that in the porosity equation, we see that as follow: (1) 2 = (2) – (3)  (4) 4.2. measurement the liquid porosity by the saturation method weighting of dry sample before and after the saturation by water was determined to calculate the pore volume using (quation5) and then calculation the liquid porosity by the equation 4: (5) 4.3. measurement the gas permeability using several values of upstream pressures in the gas permeameter, gas flow rate was recorded and darcy's law for gas was used to calculate permeability as follow: (6) 4.4. measurement the liquid permeability the plugs were saturated 100% with the fresh water for a period of time about 24 hours. absolute permeability of the liquid was defined by using geospec2 and core lab liquid permeameter. the inlet pressure in the liquid permeameter was constant (range to 25 psig), the time of 10 cc of fresh water passed through samples was recorded to practice after that in darcy's law. 5results and discussion according to the classification of folk ‎[6], grain's size, roundness and sorting were detected. table 1 shows the grain range for each core sample. the average grains size of quartz ranging from medium to very fine. most of the grains are sub-angular with a few rounded grains according folk. the grains have a well sorting and in some cases very well to moderately sorting. all these indicate that the samples have a good porosity and permeability with the exception of some samples. the percentage of mineral for each core sample was determined, as given in table 2. table 1. size, roundness and sorting degree of grains for all plugs slide no. average grains size, µm type of grain roundness sorting degree 1 0.9-1 very coarse sand sub angularhigh& low sphericity well sorted 2 1.5 pebble sub angularlow sphericity very well sorted 3 0.25 medium sub angular high& low sphericity well sorted 4 0.4-0.5 medium coarse sand sub angular high sphericity well sorted 5 0.8-1 coarse to very coarse sand sub angular low sphericity well sorted 6 0.125 0.0625 fine to very fine sand sub angularlow sphericity well sorted 7 0.4-0.5 medium coarse sand sub angular high& low sphericity well sorted 8 0.25 medium sub angular high sphericity well sorted 9 1-2 very coarse sand to pebble sub angularlow sphericity moderate ly sorted 10 0.5 coarse sand sub angularlow sphericity well sorted table 2. percentage of mineral for all core sample slide no. quartz,% feldspar,% 1 50 25 2 65 25 3 60 30 4 10 10 5 70 25 6 90 5 7 70 25 8 20 20 9 30 25 10 60 30 the rates of potassium, thorium and uranium minerals were counted by the ofite spectral gamma ray logger as shown in fig. 4 for one sample (sample no.1). table 3 shows the results of all samples. fig. 4. rates of potassium, uranium & thorium minerals for core no. (1) m. s. aljawad, a. a. ali and m. d. abdulkhadim / iraqi journal of chemical and petroleum engineering91,2 (2018) 15-20 61 table 3. results of gamma ray analysis for all plugs core no. k (%) u (ppm) th(ppm) 1 1.9 1.23 13.05 2 1.58 3.6 12.54 3 1.8 2.63 12.3 4 1.96 1.17 13.08 5 1.75 2.16 13.62 6 1.71 2.21 13.56 7 1.83 0.45 15.49 8 1.63 1.87 15.63 9 1.89 1.18 13.89 10 1.83 1.61 13.52 using the ratio of thorium/ potassium (th/k) and another technique by plotting the values of thorium verses potassium ‎[7], the volume of shale and types of clays in the samples were detected. the results listed in table 4. table 4. final results of potassium, uranium, and thorium minerals core no. volume of shale (%) minerals according to potassium content minerals according to uranium content minerals according to thorium content 1 12 shales betonies biotite 2 12 shales granite grandiorite to biotite 3 57 andesite grandiorite grandiorite to biotite 4 42 feld spathic betonies biotite 5 12 carbonates& andesite biotite biotite 6 75 andesite granodioritr biotite 7 35 carbonate andesite & basalt biotite 8 35 shales basalt granite 9 35 andesite clays granite to granite 10 35 andesite carbonate and clays schist (biotite) both of diameter, length, bulk volume, grain volume, weight of dry and wet plugs were measured to be applied in equation (4) in order to calculate the gas and liquid porosity; as shown in table 5 and table 6. table 5. results of gas porosity for all samples core no. vb, cm 3 vg, cm 3 v3, cm 3 p1, psi p2, psi (∅g), % 1 19.2 14.4 139.2 77.6 29.6 25.1 2 19.2 12.8 140.8 77.7 29.3 33.4 3 19.2 13.9 139.7 77.6 29.5 27.5 4 19.2 13.7 139.9 77.7 29.5 28.4 5 19.2 12.3 141.3 77.7 29.2 35.9 6 19.2 16.2 137.4 77.6 30 15.4 7 19.2 15.3 138.3 77.6 29.8 20.2 8 19.2 14.8 138.8 77.6 29.7 22.6 9 19.2 12.9 140.7 77.6 29.3 32.5 10 19.2 15.8 137.8 77.6 29.9 17.8 table 6. results of liquid porosity for all samples core no. dry weight, gm wet weight, gm liquid porosity (∅) % 1 40.5 43.5 15.5 2 39.3 41.8 12.9 3 41.2 43.1 9.8 4 40.2 44.5 22.3 5 37.7 40.7 15.5 6 52.2 53.1 4.6 7 40.2 42.6 12.4 8 38.8 41.3 12.9 9 39.8 42.5 14 10 41 44.6 18.7 each of porosity and permeability rates are measured in geospec2 device as shown in fig. 5 for one sample (no. 1). fig. 5. porosity &permeability results by the geospec2 apparatus for core no. (1) the flow rates of gas at different pressures were measured by perg-200 tm permeameter apparatus of gas and then tabulated in table 7 for sample no (1). the values of flow rates were differed extremely from core sample to another because of existing fractures and cracks in some samples. results of reciprocal mean pressure were plotted versus permeability as shown in fig. 6 and then corrected to eliminate the gas slippage effect by using klinkenberg correction to be then applied in darcy's law. table 7. results of gas permeability for core no. (1) q (cc/sec) p1,atm mean press.(p-) 1/p ,(atm.) kg ,(md) 18 1.34 1.170 0.854 597.2 37 1.68 1.340 0.746 535.9 62 2.02 1.510 0.662 531.3 71 2.36 1.680 0.595 410.1 m. s. aljawad, a. a. ali and m. d. abdulkhadim / iraqi journal of chemical and petroleum engineering91,2 (2018) 15-20 61 0.0 0.2 0.4 0.6 0.8 (1/p-) 100 200 300 400 500 600 k g , m d fig. 6. permeability vs. (1/p-) for core no.(1) in this way the permeability of other samples were calculated and tabulated in table 8. table 8 shows permeability results by liquid permeameter when (10) cc of fresh water was passed through samples. final results of gas and liquid porosity and permeability measured by the gas and liquid permeameter, gas prosimeter, vacuum pump in addition to the geospec2 equipment are tabulated in table 9. table 8. results of liquid permeability measurments core no. time, sec press. ,atm. differential pressure ,atm flow rate, cc/sec 1 74.4 2.46 1.462 0.13 2 118 2.49 1.49 0.08 3 100 2.54 1.54 0.1 4 40 2.47 1.47 0.25 5 80 2.49 1.49 0.125 6 0 1 0 0 7 110 2.46 1.46 0.09 8 40 2.61 1.61 0.25 9 58 2.46 1.46 0.17 10 158 2.41 1.41 0.06 table 9. final results of porosity and permeabilty core no. ∅ gas ,% ∅ liquid, % ∅ geospec, % kgc, md kl, md k geospec, md 1 25.1 15.5 11.4 120 75.1 341 2 33.4 12.9 12.4 130 47.3 192 3 27.5 9.8 13.5 54 53.2 36 4 28.4 22.34 9 140 139.6 492 5 35.9 15.5 12 200 69.8 90 6 15.4 4.6 2.4 0 0 1.57×10 -6 7 20.2 12.4 7.5 140 50.7 49 8 22.6 12.9 6.5 180 139.6 19.9 9 32.5 14.02 7.1 512 96.3 21.9 10 17.8 18.7 11.4 42 35.3 28.7 6conclusions 1the tests results that have been presented in this paper show the petrophysical properties such as gas porosity and permeability values higher than results of liquid and less than results by geospec2, this refer to capability of leak of gas in the gas porosimeter and high content of hydrogen ions in most samples using geospec2 device, therfore the results of liquid are going to be certified. 2the gas and liquid permeability of core sample number (6) were zero. by return to the scanning electrical microscope, the sample contained very small grains in addition to exist grains of iron in addition to its structure where it seems a limestone. 3from the results it is clear that the samples have a high rate of shale and type of clay was illitemontmorillonite, this indicates to probability of swelling the shale if the water injection process employ in the future causing the damage in the formation. nomenclature kg permeability of gas, md : l :length of core samples, cm d diameter of core samples, cm: a cross sectional area, cm 2 : vg grain volume, cc: v1&v 3 :constants of prosimeter, cc v2 :volume of gas inside the core holder, cc eff. effective porosity,%: density of liquid (water), gm/cc: ws weight of saturated samples, gm: wd : weight of dry samples, gm c : conversion factor equal 2000 viscosity of fluids equal 0.0176, cp: p1 :upstream pressure, psi p2 :downstream pressure, psi t :total porosity,% (1/p-) adverse of mean pressure, psi -1 : references [1] stiles, j.h. jr., and hutfilz, j.m.,(1992).'' the use of routine and special core analysis in characterizing brent group reservoirs u.k. north sea'', spe18386-pa. [2] macini, p., and mesini, e. ''petrophysics and reservoir characteristics'', http://www.eolss.net/sample-chapters/c08/e6-19305.pdf. https://www.onepetro.org/journal-paper/spe-18386-pa https://www.onepetro.org/journal-paper/spe-18386-pa https://www.onepetro.org/journal-paper/spe-18386-pa https://www.onepetro.org/journal-paper/spe-18386-pa http://www.eolss.net/sample-chapters/c08/e6-193-05.pdf http://www.eolss.net/sample-chapters/c08/e6-193-05.pdf m. s. aljawad, a. a. ali and m. d. abdulkhadim / iraqi journal of chemical and petroleum engineering91,2 (2018) 15-20 02 [3] m. s. al-jawad, a. a. ali and m. d. abdulkadhim, (2017). ''permeability alteration du to water injection in zubair reservoir/ west qurna oilfield'', msc. thesis. [4] pettijohn, f. j., potter, p. e. and siever, r. (1973).''sand and sandstone'' .springer-verlag, new york. [5] ihab s. hasan, (2011).''a sedimentological study of the zubair formation in the luhais oil field southern iraq'', (msc. thesis in university of baghdad, department of geology). [6] folk r. l., (1980).''petrology of sedimentary rocks'', hemphill, texas. [7] chapter tengamma ray/texas a&m university.https://www.coursehero.com/file/1219242 9/gr-log/ https://books.google.iq/books?hl=en&lr=&id=zctgbwaaqbaj&oi=fnd&pg=pa1&dq=%27%27sand+and+sandstone&ots=u0ho3_hpuj&sig=rrav3v7nfxlx1001em_1jaoydk4&redir_esc=y#v=onepage&q=''sand%20and%20sandstone&f=false https://books.google.iq/books?hl=en&lr=&id=zctgbwaaqbaj&oi=fnd&pg=pa1&dq=%27%27sand+and+sandstone&ots=u0ho3_hpuj&sig=rrav3v7nfxlx1001em_1jaoydk4&redir_esc=y#v=onepage&q=''sand%20and%20sandstone&f=false https://books.google.iq/books?hl=en&lr=&id=zctgbwaaqbaj&oi=fnd&pg=pa1&dq=%27%27sand+and+sandstone&ots=u0ho3_hpuj&sig=rrav3v7nfxlx1001em_1jaoydk4&redir_esc=y#v=onepage&q=''sand%20and%20sandstone&f=false https://repositories.lib.utexas.edu/bitstream/handle/2152/22930/folkpetrology.pdf?sequence=3 https://repositories.lib.utexas.edu/bitstream/handle/2152/22930/folkpetrology.pdf?sequence=3 iraqi journal of chemical and petroleum engineering vol.14 no.2 (june 2013) 16 issn: 1997-4884 the effect of promoters on the activity of prepared zeolite catalyst in fcc process abdul halim a-k mohammed and nuha ali dahyool chemical engineering department, college of engineering, university of baghdad abstract faujasite type nay zeolite catalyst was prepared from locally available kaolin, then the prepared nay zeolite have been modified by exchanging of sodium ion with ammonium to produce nh4y zeolite. nh4y zeolite was converted to hy zeolite by ion exchanging with oxalic acid. zinc and nickel promoters have been added to the prepared hy zeolite catalyst, and the effect of these promoters on the catalytic activity of the prepared hy catalyst was studied in fluid catalytic cracking process using light gas oil as a feedstock. the experimental results show that the promoted catalyst gives higher gas oil conversion and gasoline yield than hy zeolite catalyst at the same reaction temperature and whsv. it was also found that the promoted catalyst gives gasoline with lesser olefin content and higher aromatics compared with the gasoline produced by hy catalyst. keyword: fcc catalyst promoters, zeolite preparation, zeolite promoters introduction fluid catalytic cracking (fcc) is the most important conversion process used in petroleum refineries. it is widely used to convert the highboiling, high-molecular weight hydrocarbon fractions of crude oils to more valuable gasoline, olefinic gases and other products [1]. the most popular catalyst used in petroleum refineries is zeolite. most zeolites used commercially are synthetically produced. zeolite y is the most important catalytic zeolite, and is generally synthesized in the na form. most of the catalysis of interest is acid catalysis, which requires replacing the na cations by protons, converting the sieve into the h-form [2]. zeolite catalyst can be activated by addition of promoters, promoter is a substance added to a solid catalyst to improve its performance in a chemical reaction. some promoters interact with active components of catalysts and thereby alter their chemical effect on the catalyzed substance [3]. rare earth mixtures is used in fluid cracking catalysts made for the petroleum refining industry. gong et al [4] studied the effect of addition of zinc and galium promoters to hzsm-5 zeolite catalyst on its activity using vaccum gas oil as a feedstock for catalytic cracking, a modified zeolite was prepared by impregnation of zinc and galium nitrates separately. the cracking reaction conditions were: reaction temperature 510 ◦ c and catalyst/ oil ratio was 6.5 6.7 g/g and residence time of reaction 2.5 3.5 minutes, these conditions gives iraqi journal of chemical and petroleum engineering university of baghdad college of engineering http://en.wikipedia.org/wiki/oil_refinery http://en.wikipedia.org/wiki/hydrocarbon http://en.wikipedia.org/wiki/crude_oil http://en.wikipedia.org/wiki/gasoline http://en.wikipedia.org/wiki/olefin http://www.britannica.com/ebchecked/topic/99128/catalyst the effect of promoters on the activity of prepared zeolite catalyst in fcc process 2 ijcpe vol.14 no.2 (june 2013) -available online at: www.iasj.net conversion between 50 – 56.33 weight% and gasoline octane number from 89.5 to 94. trigueirp et al [5] studied the influence of the introduction of different rare earth cations , including the light (la, ce, nd, sm, gd ) and heavy elements (tb, dy, ho, er, tm ), on the thermal stability of nay zeolite catalyst. the result of this study showed that all the studied elements have the ability of the increasing thermal stability of nay type zeolite. the main objective of this work is preparation of cracking catalyst from locally kaolin clay and study the effect of impregnated of zinc and nickel promoters on the catalyst activity using gas oil as a feedstock. experimental work feedstock light gas oil with boiling range of 190 to 340 ◦ c was supplied from aldura refinery; it was used as a feedstock for fluid catalytic cracking experiments. the properties of gas oil is shown in table 1. table 1, gas oil properties 38.4 api gravity, ◦ api 21.96 viscosity at 98.8 ◦ c ,mm²/s 210 molecular weight g/mole astm distillation 190 ibp, ◦ c 208 5% volume distilled, ◦ c 282 50% volume distilled, ◦ c 302 70% volume distilled, ◦ c 340 e.p, ◦ c catalyst preparation preparation of nay zeolite catalyst kaolin was mixed with 40% weight percent sodium hydroxide solution using kaolin / naoh = 1/1.5 g/g and fused at 850˚c for 3 h. 50 g of fused kaolin and 63 g of sodium silicate were placed in 500 ml of deionized water under constant stirring at 50˚c for 1 hour, then the slurry with ph 13.3 was placed in a glass jar and subjected to ageing at 50 ᵒ c for 24 h. the produced slurry was crystallized at 100 ᵒ c for 48 h. the crystalline mass repeatedly washed with water until ph arriving to 11.7, then the crystalline mass was dried at 100 ᵒ c for 16 h. preparation of hy zeolite catalyst 100 g of nay zeolite was mixed with 600 ml of saturated aqueous solution of 1 m nh4no3 at 80 °c for 4 h, followed by filtration and washing with deionized water and drying at 100 °c for 6 h. the resultant catalyst from this step is called nh4y zeolite. nh4y zeolite was treated with oxalic acid to produce hy zeolite. 40 g of nh4y zeolite was mixed with 800 ml of 0.5 n oxalic acid at room temperature for 8 h, then the slurry was filtered and washed with deionized water and dried in an oven at 100 °c for 6 h. the dried zeolite was calcinied at 550 °c for 5 hours. table 2 shows the chemical analysis of prepared hy zeolite catalyst. table 2, chemical analysis of prepared hy catalyst component weight % sio2 62.78 al2o3 19.83 fe2o3 1.68 k2o 0.63 na2o 0.134 cao 0.89 l.o.i 5.57 preparation of promoted zeolite catalyst 100 g of hy zeolite catalyst was mixed with 226 ml of 0.15 m zn(no3)2 aqueous solution, then the resultant product was slurried by rapidly stirring at 40 ◦ c for 2 h. the resulting slurry was filtered, and the resulting filter cake was dried at 110 ◦ c for 2 h, then calcinied at 550 ◦ c for 3 h. the resulting catalyst was impregnated with 44 ml of 0.6 m ni(no3)2.2h2o aqueous solution at 40 abdul halim a-k mohammed and nuha ali dahyool -available online at: www.iasj.net ijcpe vol.14 no.2 (june 2013) 3 ◦ c for 2 h, followed filtration , drying at 110 ◦ c for 2 h, then calcination at 550 ◦ c for 3 h. fluid catalytic cracking experiments fcc experiments were carried out in a laboratory fluidized bed unit. figure1 shows the schematic flow diagram of the unit. the unit includes: dosing pump, reactor, condensation system, separation flask, gas collector and power supply box. fig. 1, schematic flow diagram of the fluidized catalytic unit (1) burette gas oil feeding; (2) burette water feeding; (3) valve1; (4) valve2 (5) dosing pump (6) three way valve (7) preheated section (8) distributor (9) fluidized bed reaction section; (10) catalyst charge inlet (11) condenser (12) control panel; (13) chilled water in; (14) chilled water out; (15) internal tube ice water bath (16) separation and collection flask (17) ice water bath (18) gas collector (19) water tank. distillation unit distillation of fcc liquid product was achieved in laboratory distillation unit, separation of gasoline fraction from the heavier cracking liquid products was achieved at this unit shown in figure 2. fig. 2, the schematic diagram of the laboratory distillation unit (1) mental heater (2) distillation flask (3) thermometer (4) distillation column (5) glass connection (6) thermometer (7) condenser (8) chilled water out (9) chilled water in. conversion conversion may be defined as the volume or weight percent of feedstock converted to gasoline and other lighter products and coke, however, conversion is typically calculated by subtracting the volume percent or weight percent of liquid products heavier than gasoline from fresh feed and dividing by the volume or weight of fresh feed. conversion% cycle stock is the portion of catalyticcracker effluent not converted to gasoline, gases and coke, generally it is the material boiling above 430°f (220°c) [6]. test methods x – ray diffraction x-ray diffraction analysis was done in the state company of geological the effect of promoters on the activity of prepared zeolite catalyst in fcc process 4 ijcpe vol.14 no.2 (june 2013) -available online at: www.iasj.net survey and mining by using maxima xrd-7000 diffractometer. sodium content the sodium content of prepared faujasite type nay zeolite before and after ion exchange with ammonium ion was determined by flame photometer galen kamp in at state company for geological survey and mineral. sodium is commonly reported as the weight percent of sodium oxide (na2o). silica and alumina the percent of silica and alumina in prepared zeolite catalyst before and after dealumination was achieved in state company of geological and mineral. surface area and pore volume determination of prepared catalyst surface area was found by bet method. pona analysis pona analysis is the analysis of hydrocarbon mixtures by separation and quantization of fractions according to the carbon number or type of hydrocarbon. pona is an acronym for paraffins, olefins, naphthenes and aromatics. pona analysis by capillary gas chromatography utilizes a non-polar chemically bonded capillary column with a high theoretical plate number to separate constituent hydrocarbons into as many peaks as possible. pona analysis features quantitation of olefins at subpercentage levels, quantitation of individual components in addition to type identification,and calculation of mean density and mean molecular weight. results and discussion characterization of prepared catalyst x-ray diffraction pattern x-ray diffraction pattern was determined for prepared nay zeolite and compared with the standared nay zeolite. the comparison between the lattice spacing between the prepared and the standared nay zeolite show that the prepared nay zeolite is approximately comparable with the standard as shown in figure 3. fig. 3, x – ray diffraction spectrum for the prepared nay zeolite sodium content na2o content of prepared nay zeolite was analyzed and it was 12.5 wt%, while hy zeolite contains only 1.34 wt%, that means the percent exchange was 89.2 %. this result is in agreement with the result published by reza and jones et al. [7]. they recorded that a typical nay zeolite contains approximately 13 wt% na2o. surface area and pore volume the surface area of prepared catalyst was measured by bet method and it was equal to 148.73m 2 /g, and this value was in the range of fcc catalyst abdul halim a-k mohammed and nuha ali dahyool -available online at: www.iasj.net ijcpe vol.14 no.2 (june 2013) 5 surface area of 125 to192 m 2 /g [8], while the pore volume was equal to0.254 cm 3 / g. effect of promoters on the catalyst activity the effect of zinc and nickel promoters on the activity of the prepared catalyst (hy zeolite) was studied at whsv = 10 h -1 and different reaction temperatures (470 530 ᵒ c). figures 4 and 5 show the effect of promoters on gas oil conversion and the yield of gasoline at different reaction temperatures, respectively. these figures show that promoted catalyst, in general gives higher conversion and gasoline yield than hy catalyst at constant temperature and whsv. the chemical composition of the catalytic cracking gasoline was analyzed using pona analysis. table 3 shows the comparison between the chemical composition of cracked gasoline fraction that produced by hy and promoted hy zeolite catalysts. table 3, comparison between the chemical compositions of cracked gasoline fraction gasoline produced using promoted zeolite catalyst gasoline produced using hy zeolite catalyst chemical composition of cracked gasoline (vol. %) 24.29 24.06 paraffins 12.3 30.14 olefins 9.31 9.2 naphthenes 54.1 36.6 aromatics it can be seen from this table that the olefin content in the produced gasoline was decreased remarkably by addition of promoters to the cracking catalyst, and the aromatic content was increased, that means addition of promoters increased catalyst activity and increased gasoline research octane number (ron). baker and whittington [9] measured the chemical composition and research octane number of cracked gasoline produced from different feedstocks and found that the ron depended mainly on the aromatic content as shown in figure 6. octane number (ron) of the produced gasoline from this work was calculated from the equation of figure 6 (aromatics = 2.436ron – 191.9), and it was equal to 93.8 for the produced gasoline using hy zeolite catalyst, while the promoted catalyst gives gasoline with octane number above 100. fig. 4, effect of promoters on gas oil conversion at whsv of 10 h -1 and different reaction temperatures fig. 5, effect of promoters on gasoline yield at whsv = 10 h -1 and different reaction temperatures the effect of promoters on the activity of prepared zeolite catalyst in fcc process 6 ijcpe vol.14 no.2 (june 2013) -available online at: www.iasj.net fig. 6 relation between ron and aromatic content for cracked gasoline conclusions addition of zn and ni promoters to the prepared hy zeolite catalyst reduces olefin content and increases aromatics in the produced gasoline. references 1. james h. gary and glenn e. handwerk, "petroleum refining: technology and economics", 4 th ed., (2001). 2. james a. kaduk and john faber, "crystal structure of zeolite y as a function of ion exchange", the rig aku journal, vol 12/no.2, (1995). 3. darlene and dr. josiph, "additive handbook", june, (2011). 4. gong xuhui, hao daijun, liu danhe and wei xiabo, "catalytic promoters and preparation", united states patent, mar 24 (2006). 5. trigueiro f.e., monteiro d.f.j.and zotin f.m.z., "thermal stability of y zeolites containing different rare earth ions ", jornal of alloys and compounds, (2002). 6. wallenstein, d., seese, m., zhaob, x., "a novel selectivity test for the evaluation of fcc catalysts", applied catalysis a: general 231, (2002). 7. schwartz,j .g., "catalytic cracking unit with external cyclone and quench system", united states patent 5089235, (1992). 8. deunis l. salbilla and akarl kolmetz, "fluidized catalytic cracker catalyst selection: equilibrium catalyst quality and considerations for selections", (2002). 9. baker, r.w., "presentation at the davison – crosfield catalyst symposium", great british, april, (1972). available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.21 no.1 (march 2020) 1 – 7 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: enas ali anwer, email: enasali024@gmail.com, name: basma a. abdul majeed, email: basma1957@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. different electrodes connections in electrocoagulation of synthetic blow down water of cooling tower enas ali anwer and basma a. abdul majeed chemical engineering department-college of engineering-university of baghdad-iraq abstract in this research, the performance of electrocoagulation (ec) using aluminum (al) electrodes with monopolarparallel (mp-p), and bipolar series (bp-s) arrangement for simultaneous removal of dissolved silica, and hardness ions (calcium, and magnesium) from synthetic blowdown water of cooling tower were investigated. the effects of current density, initial ph and time of electrolysis on the removal efficiency were studied in a batch stirred unit to find out the best-operating conditions. the obtained results for each target species are evidence that bp-s approach is the best for both electrodes configuration operated at a current density of 1ma/cm 2 through 30 min of treatment and ph=10 with the removal of 60 %, 97% and 98% for calcium, magnesium and silica, respectively. this arrangement required an electrical energy consumption of1.8 kwh/m3 which is higher than observed in a parallel arrangement. keywords: cooling tower blow down water, silica, hardness ions, electrocoagulation, monopolar-parallel, bipolarseries. received on 04/11/2019, accepted on 11/01/2020, published on 30/03/0220 https://doi.org/10.31699/ijcpe.2020.1.1 1introduction it is recognized that a system that is in contact with the circulating water, for example, cooling tower, boilers, heat exchangers are subjected to the construction of deposition on the internal surfaces. normal operation of cooling tower, consequences in the consumption of sensibly large amounts of water as makeup water, which it consists of a quantity of contamination and the impurities which, if not treated, lead to a steady build-up of deposits on the operational surfaces of the unit and as water is lost from the system, generally during evaporation, levels of concentration of these pollutants and contaminates increase and causing scaling, which is sever problem in system for the reason that the scale layer works as a thermal insulation‎[1]. silica and hardness ions, especially calcium and magnesium, are the main causes of scaling problems in cooling towers ‎[2]. to prevent scaling in cooling towers a part of the water is discharged producing a stream called cooling tower blowdown (ctb) ‎[3]. various technologies have been used to remove silica and hardness ions some of these treatments required adding chemicals for water softening such as ion exchange and chemical precipitation, and other methods do not require to add chemicals, such as reverse osmosis, electrodialysis, nano-filtration, crystallization, distillation and evaporation ‎[4]. these technologies have a number of problems like the high cost of operation, increased sludge, fouling of membrane, which demands an effluent post-treatment and removal of remaining sludge ‎[5]. one of the talented methods for the treatment of ctb water is an electrochemical technique based on ec. electrocoagulation is a green technique. in this method, there are no chemicals added as in the chemical coagulation approach. therefore, there is no difficulty in neutralizing extra chemicals and no possibility of secondary pollution started via chemical matters that added at elevated concentration. ec process as well as many advantages comprises: generating effluent with a low content of total dissolved solids (tds), required simple equipment and it is effortless to work, generating an obvious, odorless and colorless effluent. in addition, formation low quantities of sludge which consists mostly of metallic oxides/hydroxides which be inclined to be quickly settable and easy to be distant‎[6]. a simple ec cell is fabricated from anode and cathode with mp-p or bp electrodes arrangements. monopolar electrodes in a parallel arrangement (mp-p), all anodes are connected together and to the positive pole of external dcpower supply and also the cathode electrodes connected together to the negative pole of dc supply. so the current is divided between each set of electrodes(anode or cathode)resulting in lower potential difference ‎[7]. bipolar electrodes (bp-s) configuration, in this form of connection, the sacrificial electrodes are sited between the two outermost parallel electrodes (anode and cathode) are not connected to dcpower supply. https://doi.org/10.31699/ijcpe.2020.1.1 e. a. anwer and b. a. abdul majeed / iraqi journal of chemical and petroleum engineering 21,1 (2020) 1 7 2 only the outermost electrodes are connected to the power supply, as the flow of an electrical current, the neutral sides of the conductive surface of electrodes will be changed to charged sides, which have reverse charge contrast to the parallel side beside it ‎[7] ec process uses a direct current between two pairs or more from metal electrodes such as aluminum iron coagulant material that destabilize pollutants‎[8]. the ec method is a combination of various processes comprising oxidation, coagulation, flocculation and flotation ‎[9]. as a current is applied, positive ionic coagulants possibly bent due to metal anodes oxidation. successively, hydroxyl ions (oh-) will form and some o2 and h2 gas bubbles would come to pass because of water reduction evolving at the cathode. then the pollutions and suspensions particles destabilization due to transported of formed ions to oppositely charged electrodes and gone in front to break down the emulsion. the interaction between the anode metal cations (al 3+ or fe 2+ ) and the hydroxyl ions (oh ), lead to generation of metallic hydroxides of good adsorption properties, which are able of destabilizing any dispersed particles presented in the solution. the main reactions at electrodes are given in the following eqs. (1-4): anode and cathode: al → al (aq) 3+ +3e – (1) cathode: 2h2o + 2e – → h2 + 2oh – (2) formation of al (oh)3: al (aq) 3+ + 3oh – → al(oh)3 (3) the neutral form of al(oh)3 is polymerized, as follows, to form flocs which have the high-flocking capacity to eliminate the pollutants from wastewater by the adsorption process via the electrocoagulation cell ‎[10]: n al(oh)3 → aln(oh)3n (4) after adsorption of contaminants into the hydroxide structures, bigger aggregates will form, and then these aggregates can be transmitted via flotation of hydrogen and oxygen bubbles which take upwards where it is able to be more simply concentrated, gathered and distant or can be precipitated if they have a fairly elevated density in contrast with the medium‎[6]. ec has the ability to eliminate an extensive range of contaminant containing suspended solids, heavy metals, dyes, organic material, and ions‎[8]. few investigates have considered for the treatment of scale-forming species, such as ca 2+, mg 2+, and silica ions in the ctb water by ec ‎[2], ‎[11]. however, the comparison between different electrodes arrangements for removing hardness and silica ions from ctb water was never studied previously. the objective of this study is to investigate the effect of ec process parameters like current density, initial ph and treatment time for remove silica, ca 2+ and mg +2 ions from ctb water using different electrodes arrangements (monopolar parallel and bipolar series) with ec process. in addition, calculate the energy consumption for each connection of electrodes. 2experimental work 2.1. wastewater sample preparation and analysis of synthetic ctbw were conducted in the laboratory of higher education in chemical engineering at the university of baghdad. in order to prepare ctbw with initial concentration for each ion, salts like sodium metasilicate nine-hydrate (na2 sio3.9h2o), mgcl2 and cacl2 weighted using an electrical balance (bl210s: sartorius -4 digits) dissolved in 2.8 l of distilled water. initial ph and electrical conductivity of simulated water were measured using a ph meter model (atc company) and digital conductivity, meter type (sensodirect oxi 200 lovibond, england) respectively. the characteristic of synthetic ctbw is summarized in table 1. table 1. properties of simulated ctb water value units parameters 10.5 ph 50 mg/l silica 508 mg/l calcium 292 mg/l magnesium 2500 s/cmµ electrical conductivity 2.2. experimental set-up the experimental set-up for both electrodes arrangements is conducted in a rectangular ec cell of 3l having dimensions of (16×16×12)cm made of glass material on a magnetic stirrer (type stuart, cb162). four aluminum electrodes of the same dimensions (130×130×1) mm with an active area of 260 cm 2 for single electrodes immersed vertically in the electrolytic solution. the distance between each electrode was maintained at 1.5 cm for mp-p and bp-p experiments. dc power supply (syadgong companymodel: ps-305d) was used to provide a constant current for ec cell. ec reactor with (mp-p) and (bp-s) electrodes configurations are illustrated in fig. 1 (a) and (b) respectively. e. a. anwer and b. a. abdul majeed / iraqi journal of chemical and petroleum engineering 21,1 (2020) 1 7 3 for bp-s configuration, the voltage connected between the electrodes via the power supply, leads to polarization of the middle bipolar electrodes, which at the point, show diverse polarities within the inverse face present different polarities in the opposite faces. fig. 2 explains the charge distribution for both configurations. the reactor was experienced with simulated ctbw samples of various ph values (5,9, 7, and 10) and three current densities ( 0.25,0.5, 1, and 2 ma/cm 2 ) below each experiment conditions, the treated samples (50ml) were with drown from the center of the cell through reaction durations and then were analyzed. experiments of both electrodes connections were carried out at laboratory temperature and at 250 rpm of stirring rate based on the previous study‎[6]. (a) (b) fig. 1 representation view of the ec cell and schematic diagram: ( a) mp-p (b) bp-s (a) (b) fig. 2. charge distribution on electrodes (a) mp-p (b) bps ‎[12]. 3analytical methods the final concentration of silica ion for each sample was determined using the ultraviolet spectrophotometer model (uvcecdil, england) with a wavelength of (815 nm) in al-duara thermal power plant, baghdad. iraq. calcium and magnesium concentrations were determined using atomic absorption spectroscopy (aastype – shimadzu -7000f) in central service laboratory / abnalhaithem collage. the removal efficiency (η %) of each species was calculated using the eq.5 ‎[2]: η % = 100 (5) where: ci and cf are the initial and final ions concentrations (mg/l) electrical energy consumption eec (kw h /m 3 ), is an essential economic factor in the electrocoagulation method. the eec was estimated using eq.6 ‎[3]. eec = (6) where: u is the voltage (volt), i is the current (a), t is the treatment time (h) and v is the volume of treated samples (m 3 ). 4results and discussion 4.1. effect of electrolysis time to deal with the effect of the treatment time, the experiments were conducted for ec with both electrodes arrangement at the time ranged from 15 to 60 minutes at current density 0.25ma/cm 2 . the calcium, magnesium and silica ions removal efficiencies depend straight on the amount of aluminum generation via the electrodes, which is related to time, while by multiplication of the electrolysis time, an increase occurs in the concentration of ions and their hydroxide flocs. for that reason, as revealed in fig. 3, for mp-p connections, an increase in the time of electrolysis from 15 min to 30 min yields an increase in the efficiency of calcium removal from 10.7 to 15.85%., magnesium from 80.63 % to 85.71%, and silica from 83% to 86.41%. also, for bp-s connections as shown in fig. 4, the removal scale-forming ions were increased at the time of 15 to 30 min to attain removal efficiencies 23.71% to 25.92% for ca, 85.73% to 88.62% for mg, and 91% to 98.24% for silica. for both electrodes configurations, the removal efficiency of ions was increased with time and reached its highest value at the time of 30 min and increased steadily until the end of the treatment time of 60 min, so the best time was taken as 30 min for both electrodes connection. e. a. anwer and b. a. abdul majeed / iraqi journal of chemical and petroleum engineering 21,1 (2020) 1 7 4 fig. 3. effect of the time of electrolysis on the removal efficiency of calcium, magnesium, and silica with mp-p connections of electrodes fig. 4. effect of the time of electrolysis on the removal efficiency of calcium, magnesium, and silica with bp-s connections of electrodes 4.2. effect of current density it is known that current density (cd) not simply finds out the coagulant dosage rate, other than also the bubble development rate, size and the flocs increment which can impact the treatment efficiency of the electrocoagulation‎[13]. the effect of cd on removal ions efficiency was studied at 0.25, 0.5, 1, and 2 ma/cm 2 and 30 min of ec time. it was seen from fig .5 for mp-p system, an increase of current density from 0.25 to 1 ma/cm 2 yields an improved in the removal efficiency from 25.3% to 35.21%, 88.06 to 95.21%, and 94 to 97.11% for ca, mg and silica ions, correspondingly. also, for the bp-s system, fig.6 explained the progressively increased of ions removal efficiencies with current density from 0.25 t0 1ma/cm 2 , and after that remind fairly stable until the end of the experiment. so for both systems, an increment in current density delivers the anodic oxidation to require put more readily, which in turn favors the arrangement of amorphous aluminum hydroxides species satisfactorily within the region of the anode as well as within the bulk ‎[14]. in the ec cell with bp-s, a higher surface area contrasted to that of mp-p preferential the adequate anodic oxidation. thus, with the same current density for both sort of connection, the intensity is higher in the bipolar connection, as a result, the removal efficiency of ions was obtained more than that was observed in mp-p arrangement ‎[15]. fig. 5. effect of the current density on the removal efficiency of scale-forming ions with mp-p cell at time=30min fig. 6. effect of the current density on the removal efficiency of scale-forming ions with bp-s cell at time=30min e. a. anwer and b. a. abdul majeed / iraqi journal of chemical and petroleum engineering 21,1 (2020) 1 7 5 4.3. effect of initial ph it has been recognized that ph is a significant factor that effect on the performance of the ec process‎[16]. to study its effects on the removal efficiency of ions for both systems, the model wastewater was adjusted to a preferred value for each experiment using a sodium hydroxide solution or sulfuric acid solution (0.1m). mpp and bp-p modes were studied to remove ions forming scaling from simulated ctbw in the initial ph of 5, 7, 9 and 10 at 1 ma/cm 2 and 30 min of reaction time. fig. 7 and fig. 8 established the efficiency of calcium, magnesium and silica removal as function of the initial ph solution for mp-p and bp-p connection modes respectively, with maximum removal efficiency were 40 %, 95%, and 96%, for mp-p and 60.18%, 97 % and 98% for bp-s at ph=10. the efficiency of ions removal increased with ph increasing, it has been observed that both configurations of electrodes are effective in silica removal at ph=5 and 7 while the removal of ca and mg species were less, but at initial ph=10 the removal of hardness ions enhanced, this fact has as well been recognized by liao in his study on the treatment of ctbw containing silica, magnesium and calcium ions via ec process with bp-s electrodes arrangement [11]. and also, with malakootian investigation on hardness ions removal using ec with mp-p electrodes connections ‎[17]. the reason of the increase of removal efficiency of silica can be attributed to chemical adsorption, while in case of the calcium and magnesium removal that for aluminum hydroxides, much higher ph values are needed to credited negatively charged precipitate, that means the mechanisms of ca +2 and mg +2 ions includes physical adsorption, which consequences from electrostatic attraction via ca +2 and mg +2 to negatively charged sites on the precipitates ‎[11]. fig. 7. removal percent efficiency of silica ca, and mg for mp-p of ec cell at different initial ph value, at time=30min and current density=1ma/cm 2 fig. 8. removal percent efficiency of silica ca, and mg for bp-s of ec cell at different initial ph value, at time=30min and current density=1ma/cm 2 4.5. electrical energy consumptions for both electrodes arrangement, it is clear that current and voltage values powerfully influence the choice of the type of electrode configuration for given wastewater treatment. fig.9 showed the change of eec values with time for scale shaping species removal at current density =1ma/cm 2 and ph=10 for mp-p and bp-s connections .it was observed that bp-s has the higher energy consumption than mp-p system for the same current density and this agreement with kobya investigation[7]. fig. 9. the difference of eec values with time for scaleforming ions removal for mp-p and bp-s connection at ph=10, (i = 1 ma/cm2) 5conclusion  electrocoagulation was assessed as a possible technique for the removal of ions causing scaling (silica, calcium, and magnesium) from synthetic cooling tower blowdown water using mp-p and bp-s.  the results for eec demonstrate that mp-p attained the lowest energy consumption in comparison with bp-s. e. a. anwer and b. a. abdul majeed / iraqi journal of chemical and petroleum engineering 21,1 (2020) 1 7 6  the experiments were showed that bp-s mode has higher removal efficiency for each ion from ctbw. therefore, this array generates more flocs than the mp-p mode. in addition, the growing al +3 ions are more efficient in the coagulation method and it is renowned that aluminum hydroxide flocs are relatively big and having low density, which can be simply floated and separated [13].  bp-s configuration is a simple system, only the outer electrodes are connected to the power supply and the inner electrodes without connections, which assist no difficulty of maintenance. nomenclature nomenclature meaning units ci initial ions concentrations mg/l cf final ions concentrations mg/l % η removal efficiency eec electrical energy consumption kwh/m 3 i current ampere u voltage volt t time of electrolysis hour v solution volume m 3 references [1] s.abdul rahman ahmed reshan, “zinc element traces to inhibit scale formation on cooling tower and air cooler systems,” ijcpe, vol. 14, n, pp. 41–48. [2] o. m. hafez, m. a. shoeib, m. a. el-khateeb, h. i. abdel-shafy, and a. o. youssef, “removal of scale forming species from cooling tower blowdown water by electrocoagulation using different electrodes,” chem. eng. res. des., vol. 136, pp. 347–357, 2018. [3] c. wang, “removal of silica from cooling water by electrocoagulation :,” asian j. chem., vol. 25, no. 16, pp. 9309–9314, 2013. [4] m. malakootian, h. j. mansoorian, and m. moosazadeh, “performance evaluation of electrocoagulation process using iron-rod electrodes for removing hardness from drinking water,” des, vol. 255, no. 1–3, pp. 67–71, 2010. [5] o. gorni-pinkesfeld, d. hasson, r. semiat, and h. shemer, “hybrid electrolysis – crystallization system for silica removal from aqueous solutions,” desalination, vol. 407, pp. 41–45, 2017. [6] r. h. salman, “removal of manganese ions (mn2+) from a simulated wastewater by electrocoagulation/ electroflotation technologies with stainless steel mesh electrodes: process optimization based on taguchi approach,” iraqi j. chem. pet. eng., vol. 20, no. 1, pp. 39–48, 2019. [7] y. demirci, l. c. pekel, and m. alpbaz, “investigation of different electrode connections in electrocoagulation of textile wastewater treatment,” int. j. electrochem. sci., vol. 10, pp. 2685–2693, 2015. [8] a. a-mohammed, “electrocoagulation of phenol for wastewater treatment”, ijcpe, vol. 9, no. 3, pp. 45-49, sep. 2008. [9] n. bouchaibgourich, m. youssefstiriba, c. patrick, and d. jamalnaja, “electrocoagulation process in water treatment : a review of electrocoagulation modeling approaches,” desalination, vol. 404, no. february, pp. 1–4, 2017. [10] f. yasir and w. t. mohammed, “analyzing the removal of lead from synthesis wastewater by electrocoagulation technique using experimental design,” desalination and water treatmen,t vol. 111, pp. 286–296, 2018. [11] z. liao, s. p. corporation, j. r. davis, and j. farrell, “treatment of cooling tower blowdown water containing silica , calcium and magnesium by electrocoagulation silica , calcium and magnesium by electrocoagulation,” water sci. technol., no. november, 2009. [12] n. fayad, “the application of electrocoagulation process for wastewater treatment and for the separation and purification of biological media,” grad. theses diss., pp. 5–226, 2018. [13] n. modirshahla, m. a. behnajady, and s. kooshaiian, “investigation of the effect of different electrode connections on the removal efficiency of tartrazine from aqueous solutions by electrocoagulation,” dye. pigment. 74, vol. 74, pp. 249–257, 2007. [14] d. ghosh, c. r. medhi, m. k. purkait, and a. al, “chemosphere treatment of fluoride containing drinking water by electrocoagulation using monopolar and bipolar electrode connections,” chemosphere, vol. 73, no. 9, pp. 1393–1400, 2008. [15] m. i. alali, “performance evaluation of electrocoagulation technique for removing groundwater hardness of tikrit university,” eng. tech. j., vol. 30, no. 18, 2012. [16] m. asselin, p. drogui, h. benmoussa, and j. blais, “ effectiveness of electrocoagulation process in removing organic compounds from slaughterhouse wastewater using monopolar and bipolar electrolytic cells,” chemosphere, vol. 72, pp. 1727–1733, 2008. [17] m. malakootian and n. yousefi, “the efficiency of electrocoagulation process using aluminum electrodes in removal of hardness from water,” environ. heal. sci. eng., no. january, 2009. http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/312 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/312 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/312 https://www.sciencedirect.com/science/article/abs/pii/s0263876218302843 https://www.sciencedirect.com/science/article/abs/pii/s0263876218302843 https://www.sciencedirect.com/science/article/abs/pii/s0263876218302843 https://www.sciencedirect.com/science/article/abs/pii/s0263876218302843 https://www.sciencedirect.com/science/article/abs/pii/s0263876218302843 https://www.sciencedirect.com/science/article/abs/pii/s0011916410000378 https://www.sciencedirect.com/science/article/abs/pii/s0011916410000378 https://www.sciencedirect.com/science/article/abs/pii/s0011916410000378 https://www.sciencedirect.com/science/article/abs/pii/s0011916410000378 https://www.sciencedirect.com/science/article/abs/pii/s0011916410000378 https://www.sciencedirect.com/science/article/abs/pii/s001191641631774x https://www.sciencedirect.com/science/article/abs/pii/s001191641631774x https://www.sciencedirect.com/science/article/abs/pii/s001191641631774x https://www.sciencedirect.com/science/article/abs/pii/s001191641631774x https://doi.org/10.31699/ijcpe.2019.1.6 https://doi.org/10.31699/ijcpe.2019.1.6 https://doi.org/10.31699/ijcpe.2019.1.6 https://doi.org/10.31699/ijcpe.2019.1.6 https://doi.org/10.31699/ijcpe.2019.1.6 https://doi.org/10.31699/ijcpe.2019.1.6 http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.670.466&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.670.466&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.670.466&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.670.466&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.670.466&rep=rep1&type=pdf http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/446 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/446 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/446 https://www.sciencedirect.com/science/article/abs/pii/s0011916416315971 https://www.sciencedirect.com/science/article/abs/pii/s0011916416315971 https://www.sciencedirect.com/science/article/abs/pii/s0011916416315971 https://www.sciencedirect.com/science/article/abs/pii/s0011916416315971 https://www.sciencedirect.com/science/article/abs/pii/s0011916416315971 https://www.deswater.com/dwt_abstracts/vol_111/111_2018_286.pdf https://www.deswater.com/dwt_abstracts/vol_111/111_2018_286.pdf https://www.deswater.com/dwt_abstracts/vol_111/111_2018_286.pdf https://www.deswater.com/dwt_abstracts/vol_111/111_2018_286.pdf https://www.deswater.com/dwt_abstracts/vol_111/111_2018_286.pdf https://iwaponline.com/wst/article-abstract/60/9/2345/14130 https://iwaponline.com/wst/article-abstract/60/9/2345/14130 https://iwaponline.com/wst/article-abstract/60/9/2345/14130 https://iwaponline.com/wst/article-abstract/60/9/2345/14130 https://iwaponline.com/wst/article-abstract/60/9/2345/14130 https://iwaponline.com/wst/article-abstract/60/9/2345/14130 https://www.sciencedirect.com/science/article/abs/pii/s0143720806000738 https://www.sciencedirect.com/science/article/abs/pii/s0143720806000738 https://www.sciencedirect.com/science/article/abs/pii/s0143720806000738 https://www.sciencedirect.com/science/article/abs/pii/s0143720806000738 https://www.sciencedirect.com/science/article/abs/pii/s0143720806000738 https://www.sciencedirect.com/science/article/abs/pii/s0143720806000738 https://www.sciencedirect.com/science/article/pii/s0045653508011193 https://www.sciencedirect.com/science/article/pii/s0045653508011193 https://www.sciencedirect.com/science/article/pii/s0045653508011193 https://www.sciencedirect.com/science/article/pii/s0045653508011193 https://www.sciencedirect.com/science/article/pii/s0045653508011193 https://www.iasj.net/iasj?func=fulltext&aid=66157 https://www.iasj.net/iasj?func=fulltext&aid=66157 https://www.iasj.net/iasj?func=fulltext&aid=66157 https://www.iasj.net/iasj?func=fulltext&aid=66157 https://www.sciencedirect.com/science/article/pii/s0045653508005821 https://www.sciencedirect.com/science/article/pii/s0045653508005821 https://www.sciencedirect.com/science/article/pii/s0045653508005821 https://www.sciencedirect.com/science/article/pii/s0045653508005821 https://www.sciencedirect.com/science/article/pii/s0045653508005821 https://www.sid.ir/en/journal/viewpaper.aspx?id=141263 https://www.sid.ir/en/journal/viewpaper.aspx?id=141263 https://www.sid.ir/en/journal/viewpaper.aspx?id=141263 https://www.sid.ir/en/journal/viewpaper.aspx?id=141263 e. a. anwer and b. a. abdul majeed / iraqi journal of chemical and petroleum engineering 21,1 (2020) 1 7 7 المحاكة لبرج التبريد التوصيالت المختمفة لألقطاب في التخثير الكهربائي لمياه التصريف ايناس عمي انور و بسمة عباس عبدالمجيد جامعة بغداد, كمية اليندسة, قسم اليندسة الكيمياوية الخالصة ( مع ترتيب al( باستخدام أقطاب األلمنيوم )ecأداء عمميو التخثير الكيربائي ) تم دراسة في ىذا البحث ، ( لإلزالة المتزامنة لمسيميكا الذائبة ، وأيونات bp-s( ، وسمسمة ثنائية القطب )mp-pأحادي القطب المتوازي ) تمت دراسة تأثيركثافة الصالبة )الكالسيوم ، والمغنيسيوم( من مياه التصريف المحاكاة من برج التبريد.وكذلك التيار ، ودرجة الحموضة األولية ووقت التحميل الكيربائي عمى كفاءة اإلزالة في وحدة دفعية لمتعرف عمى أفضل ىو bp-s نظام ظروف تشغيل. النتائج التي تم الحصول عمييا لكل األنواع المستيدفة ىي دليل عمى أن مع إزالة 10دقيقة وقيمو االس الييدروجيني = 30خالل 2امبير/سمممي 1األكثر فعالية بكثافة تيار مقدارىا ٪ لمكالسيوم والمغنيسيوم والسيميكا ، عمى التوالي ، يتطمب استيالك طاقة كيربائية 79٪ و ٪79 ، 00 كيمو واط ساعة / متر مكعب اعمى مما يالحظ في الربط المتوازي. 1,9بمقدار بريد, سيميكا, سمسمة ثنائية االقطابالكممات لدالة: مياه برج الت iraqi journal of chemical and petroleum engineering vol.15 no.4 (december 2014) 9-14 issn: 1997-4884 naphtha desulfurization by prepare cu-ni-zeolite adsorbent abdul-halim a. mohammed a and maha a. abdulwahhab b chemical engineering department-college of engineering-university of baghdad-iraq abstract for desulfurization of naphtha, nay zeolite was prepared from dewekhala kaolin clay (al-anbar region). for the prepared zeolite adsorbent, x-ray diffraction, sodium content, silica to alumina ratio, surface area, bulk density and crushing strength were determined. from the x-ray diffraction of the prepared nay zeolite and by a comparison with the standard nay zeolite, it was found that the prepared adsorbent in this work has approximately the same crystal structure as the standard. adsorption process was done in a laboratory unit at 25 ᵒ c and 4.1 h -1 lhsv. the experimental results show that the promoted adsorbent gives higher percentage of sulfur removal (82.15%) after 10 minute and reaching 40.15% after 120 minute. the adsorption capacity is equal 0.167 mmole "s"/ g after 10 minute while it reached up to 0.77 and 0.98 mmole "s"/g at 50 and 120 minute, respectively. keywords: zeolite nay, naphtha, desulfurization. introduction the presence of sulfur compounds in petroleum fractions is highly undesirable since they result in corrosion, environmental problems and reduction performance of engines. removal of sulfur compounds from naphtha solutions has been investigated by using adsorption methods. y-type zeolite with loading metal, activated carbon, zeolite 5a, and zeolite 13x were used for this purpose [1]. kikkinides and et al. (1995) studied the removal of h2s from pre-dried natural gas contains 1000 ppm h2s and 5% co2 by using zeolite 5a. the purified adsorption product contains 0.5 -1 ppm h2s [2]. herna´ndez-maldonado and yang (2004) studied the desulfurization of diesel, gasoline, and jet fuels by sorbents obtained by ion exchanging faujasite type zeolites with cu + , ni 2+ or zn 2+ cations using different techniques, including liquid phase ion exchange, and vapor phase ion exchange . they found that the adsorption amount in the vapor phase decreases at 300°c, rather than 450 °c, and they found that the adsorption capacity in liquid phase for cu-y decreases with decreasing the temperature from 450 °c to 350 °c with ultra high purity helium and decrease more by using dry air [3]. et al. and fradet,. (2004) studied adsorption process for natural gas treatment by zeolite and activated charcoal adsorbents. they found that tetra hydro thiophene adsorption capacity is about ten times higher for iraqi journal of chemical and petroleum engineering university of baghdad college of engineering naphtha desulfurization by prepare cu-ni-zeolite adsorbent 10 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net zeolite than for activated charcoal [4]. nanoti and dasgupta (2011) studied the effect of changing in parameter for the prepared zeolite on desulfurization process for naphtha. they changed the type of active components (cu-ni-y, zn-y, cu-mn-y, cu-me-y) on the adsorbent, and the number of metal in each sample. they found that the sulfur capacity reduced from 500 mg/g in naphtha at 45 °c to 55 mg 's' /g for cu-mn-y and zn-y, and reduced to 60 mg 's'/g for cu-ni-y, so they concluded that the adsorption capacities of ion exchange y-zeolite system gives the best results in terms of exhibiting adsorption capacities (greater than 55 mg/g) [5]. this work deals with the preparation of nay zeolite promoted with cu-ni and using it in desulfurization of naphtha experimental work materials feed stock naphtha with boiling range 30180 ◦ c was supplied from al-dura refinery; and used as a feedstock for desulfurization, the properties of naphtha are given in table 1. table 1: naphtha properties 0.678 specific gravity@ 15.6 ◦ c/15.6 ◦ c 14.09 reid vapor pressur @ 37.8 ◦ c ,(kg/cm 2 ) 31.0 initial boiling point , ◦ c 010 end boiling point , ◦ c 050 sulfur content , ppmw 0.89 aromatic , volume % 0.03 olefin , volume % 4.20 naphthenes , volume % 51.78 n-paraffins , volume % 43.1 isoparaffins , volume % 50 ron clear kaolin clay the kaolin clay was supplied from state company of geological surveying and mining, it available locally in al dewekhala quarry in al – enbar region. this kaolin was used as a raw material for the adsorbent preparation. the chemical analysis of kaolin given in table 2. catalyst preparation of nay zeolite kaolin was sieved to a particle size ≤ 75µm. the kaolin with particles of ≤ 75µm was mixed with 40% sodium hydroxide solution using kaolin / naoh = 1/1.5 and fused at 850˚c for 3 hours. 50 g of fused kaolin and 63 g of sodium silicate were added to 500 ml of deionized water under constant stirring at 50˚c for 1 hour by electrical magnetic stirrer . the slurry of previous step with ph 13.3 was placed in 1000 ml glass jar and subjected to ageing at 50 ᵒ c for 24 hr in a programmable electrical furnace. the product was crystallized at 100 ᵒ c for 48 hr in a programable electrical furnace. the crystalline mass was filtrated using buckner funnel with the aid of a vacuum pump and washed with deionized water until arriving ph to 11.7. the washed crystalline was dried at 100 ᵒ c for 16 hours by using programable electrical furnace. the chemical analysis of nay was done by wet chemical analysis and achieved in state company of geological surveying and mining, as given in table (2). table 2: chemical analysis of kaolin and nay nay kaolin component, wt% 41.50 49.64 sio2 1.09 1.72 fe2o3 20.85 34.05 al2o3 1.10 1.10 cao 20.30 12.28 l.o.i. 13.46 0.46 na2o 1.7 0.75 others 100.00 100.00 total preparation of promoted zeolite catalyst promoted zeolite was obtained by ion exchanging process of prepared nay zeolite with copper nitrate solution, abdul-halim a. mohammed and maha a. abdulwahhab -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 11 followed by nickel chloride solution. 100 g of nay zeolite was mixed with 283 ml of saturated aqueous solution of 0.5 m cu(no3)2 at a room temperature for 48 hours, followed by washing with de-ionized water . the resultant from previous step mixed with 346.7 ml of saturated solution of 0.5 m of nicl.6h2o at a room temperature for 48 hours, followed by washing with de-ionized water and drying at about 90 ᵒ c for 24 hours. during the ion exchange, ph was kept at 6 to avoid hydrolysis of nickel species in solution. the prepared dried promoted adsorbent contains 3.62 wt% of na2o, 3.80 wt% of ni and 5.34 wt% of cu. fixed bed adsorption experiments the desulfurization adsorption experiments were carried out in a laboratory fixed bed unit. the unit includes: dosing pump, absorber and separating flask. the adsorber loaded with the 50 cm 3 of adsorbent from the top of the adsorber. the experiment started with a constant lhsv 4.1 h -1 , and the samples were taken after each 10 minute. the last sample was taken after 120 minute. figures 1 shows the schematic diagram of the adsorption unit. 1dosing pump and volumetric flow rate. 2adsorber. 3separation flask. fig. 1 schematic diagram of the adsorption unit test methods the sulfur content for treated naphtha was done in al-dura refinery by using antek instrument 9000n-s (usa) according to astm d 5453. sodium contentand and silica to alumina of prepared nay determined by wet chemical analysis in at state company for geological survey and mining. x– ray diffraction analysis was done in the research center of chemistry and petrochemical – ministry of science and technology. surface area of adsorbent was determined using bet method by thermo finnegan type , apparatus located at petroleum development and research center , ministry of oil. bulk density is determined in the petroleum research and development center by a bulk density device autotap-quantchrom/us. crushing strength of the zeolite granules was obtained by using the testing device (crush bk – crush strength from ma materials technologies, usa). results and discussion the comparison between the lattice spacing obtained by x-ray diffreaction shows that the prepared nay zeolite is approximately comparable with the standard. table 3 shows the comparison between lattice spacing of prepared nay zeolite with standard synthesis faujasite, while figure 2 shows x-ray diffraction pattern of prepared zeolite. the value of relative crystallinities determined by equation 1 was 140%. … (1) naphtha desulfurization by prepare cu-ni-zeolite adsorbent 12 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net this result is agreed with published by n. ali [6]. fig. 2: x– ray diffraction spectrum for the prepared nay zeolite table 3: comparison of lattice spacing, between prepared catalyst and standard synthesis faujasite –na standard synthesis faujasitena prepared catalyst d, spacing(å) angle (2theta) deg. d, spacing(å) angle (2theta) deg. 7.02 12.59 7.06 12.51 4.36 18.65 4.77 18.57 4.07 21.80 4.09 21.70 3.30 26.64 3.78 26.85 3.15 28.27 3.31 28.14 3.01 29.27 3.16 29.41 2.76 30.64 2.92 30.5 2.70 32.04 2.77 32.20 2.66 33.56 2.67 33.42 2.53 35.90 2.50 35.79 2.4 37.72 2.37 37.88 2.23 40.3 2.24 40.20 the prepared adsorbent was modified by exchanging sodium ion with copper ion and nickel ion using copper nitrate and nickel chloride solution, respectively. na2o content of prepared nay zeolite before and after ion-exchange were 13.46 and 3.62 wt%, respectively, this means that the percent exchange was 73.1 %. this result is in agreement with the result published by reza and jones et al [7, 8]. the surface area of prepared adsorbent was measured by nitrogen physical adsorption at liquid nitrogen temperature using the bet (brunauer, emmett, and teller) method, and it equals to 210 m 2 /gm, while the bulk density is equal to 0.599 gm/cm 3 and the crushing strength is 0.203 n/mm. the most preferred surface area of adsorbent with gamma alumina support is higher than 100 (m 2 /gm) [9]. a high surface area is obvious due to the micro porosity of prepared powdered zeolite [10]. an increase in surface area generally increases the adsorbent capacity. the result of surface area agreed with olguin [11], yaseen muhammad, chunxi li [12], the results of bulk density is agreed with kareem nassrullah, who prepared zeolite 5a with the bulk density of 0.597 gm/cm 3 [13]. figure 3 shows the breakthrough curve of naphtha adsorption at 25 °c and atmospheric pressure. this figure shows that the value of the effluent total sulfur concentration (ppm) per the total sulfur concentration in the feed (ppm) [c/co] increases with increasing duration time reaching 0.59 after 120 minute. figure 4 shows the effect of adsorption duration time on sulfur removal of naphtha at 25 °c and atmospheric pressure. this figure shows that the promoted adsorbent gives higher percentage of sulfur removal (82.15%) after 10 minute then the sulfur removal becomes lower and lower until reaching 40.15% after 120 minute. this result is not far from those obtained by herna´ndezmaldonado and yang [3] . the dynamic adsorption capacity of promoted nay is calculated from summation of accumulative adsorption after a given time by equation 2. … (2) where, qi =the quantity of the sulfur adsorbed per unit mass of nay zeolite adsorbent abdul-halim a. mohammed and maha a. abdulwahhab -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 13 at any given time, milimole adsorbate/gram adsorbent. co =initial concentration of adsorbate (s), miligrams/mililiter. ci= effluent concentration of adsorbate at a given time, milligrams/mililiter. m.wt = molecular weight of sulfur, milligram/milimole m= mass of adsorbent, grams. q= volumetric flow rate, mililiter/minute. t = time of sampling, minutes. the adsorption capacity is equal 0.167 mmole "s"/ g after 10 minute while it reach up to 0.77 and 0.98 mmole "s"/ g after 50 and 120 minute, respectively. these results are in agreement with data published by welters and vorbeck [14] , ma and velu [15] and anshu and dasgupta [5]. fig. 3: breakthrough curve of naphtha adsorption with duration time fig. 4: the effect of adsorption duration time on sulfur removal of naphtha conclusions the comparison of x-ray diffraction pattern of prepared nay zeolite and the standard zeolite shows a good agreement with relative crystallinity of 140%. from the adsorption process at a room temperature and lhsv 4.1 h -1 , promoted nay adsorbent givers higher sulfur removal for naphtha after 10 min then it decreases with time. references 1s. h. salem (1994), "naphtha desulfurization by adsorption". king fahd university of petroleum & minerals, dhahran 31261, saudi arabia. 2e. kikkinides, v. sikavitsas, and r. yang, "natural gas desulfurization by adsorption: feasibility and multiplicity of cyclic steady states", ind. eng. chem. res., 34, 255-262, (1995). 3a. j. herna´ndez-maldonado, f. h. yang," desulfurization of transportation fuels by πcomplexation sorbents: cu(i), ni(ii), and zn(ii)-zeolites". university of michigan, ann arbor, mi 48109-2136, usa. received 12 march 2004. 4a. fradet, s. maestri, and s.maurel, "natural gas desulphurization by adsorption", gaz de france research and development division, france, (2004). 5a. nanoti, s. dasgupta, "a zeolite based vapor phase adsorptive desulfurization process for naphtha", indian institute of petroleum, dehradun 248005, india, sintef materials and chemistry, 0314 oslo, [2011]. 6n. a. dahyool, "the effect of promoters on the activity and life time of prepared zeolite catalyst in fcc process ", 2012. 7r. sadeghbeigi, "fluid catalytic cracking handbook design, operation and troubleshooting of fcc facilities", elsevier inc, (2000). 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0 50 100 150 c/co c /c o time , min breakthruogh curve 0 20 40 60 80 100 0 50 100 150 time , min s u lf u r re m o v a l % naphtha desulfurization by prepare cu-ni-zeolite adsorbent 14 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net 8j.g. schwartz, "catalytic cracking unit with external cyclone and quench system", united states patent 5089235, (1992). 9j. t. miller w. j. reagan, " selective hydrodesulfurization of fcc naphtha with supported mos2 catalysts: the role of cobalt ", march 15, 2000. 10s. m. auerbach, k. a. carrado, and p. k. dutta "handbook of zeolite science and technology", marceld ekkeirnc inc, (2003). 11e. olguin, m. vrinat, "the use of tio2-al2o3 binary oxides as support for mo-based catalyst in hydrodesulfurization of theophthene and dibenzotheophthene". institute de recherché sur la catalyse, 69626 villeurbannce. received 22 november 1996. 12y. muhammad, c. li, " dibenzothiophene hydrodesulfurization using in situ generated hydrogen over pd promoted alumina-based catalysts" college of chemical engineering, beijing university of chemical technology, beijing 100029, pr china received 1 august 2010 . 13z. k. nassrullah "preparation and formation of zeolite 5a from the kaolin clay for drying and desulfurization of liquefied petroleum gas", 2012. 14w.j.j. welters, g. vorbeck, "hds activity and characterization of zeolite-supported nickel sulfide catalysts", recived 15 –april – 1994. university of technology, rotterdamseweg 137, 2628 al delft. 15x. ma and s. velu, "deep desulfurization of gasoline by selective adsorption over solid adsorbents and impact of analytical methods on ppm-level sulfur quantification for fuel cell applications", received 3 february 2004. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.20 no.3 (september 2019) 59 – 66 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: jalal a. al-sudani, email: julsud@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. re-evaluation of petro physical properties in yammama formation at nasiriya field karrar hayder jassim and jalal a. al-sudani department of petroleum/ university of baghdad abstract nasiriya field is located about 38 km to the north – west of nasiriya city. yammama, a giant lower cretaceous reservoir in nasiriya field which is lithologically formed from limestone. yammama mainly was divided into three main reservoir units ya, yb1, yb2 and yb3 and it is separated by impermeable layers of variable thickness. an accurate petro physical evolution of the reservoir is of great importance perform an excellent geological model so that four petro physical properties which are shale volume, porosity, water saturation and permeability was re-evaluated. the volume of shale was calculated using the density and neutron logs (vshdn) rather than using gamma ray log because of presence a uranium content in the formation that makes overestimation of shale volume. cross plots of density neutron logs are used to determine porosity by using ip software, which is correcting automatically density neutron logs for the effect of shale. indonesian equation was used to estimate water saturation for five wells rather than archie equation in order to consider shale volume. fuzzy logic was adopted to predict permeability instead of regression analysis (cross plot) because of presence of errors in the results in this method. the results are shown that units yb2 and yb3 have best reservoir quality. keywords: shale volume, porosity, water saturation, permeability, fuzzy logic received on 09/12/2018, accepted on 14/04/2019, published on 30/09/1029 https://doi.org/10.31699/ijcpe.2019.3.8 1introduction to evaluate formation, the determination of shale volume, permeability, porosity and fluid saturation are very essential in the estimation of the hydrocarbon in place. these petro physical properties are important to know the nature of the reservoir, and lead to plan to develop the field. the accurate calculations of petro physical properties in carbonate reservoirs are the most critical point to interpret well log ‎[1]. shale is considered most radioactive than sand or limestone. in order to calculate shale volume in reservoir, gamma ray log can be used. the volume of shale is expressed as a percentage or decimal fraction. when radioactive materials are present in porous reservoir other than shale, for example where sand appears to be shale, overestimation of shale volume from gamma rays log is appear. in this case, shale volume estimation from other logs are highly recommended to avoid over or under estimation of shale volume ‎[2]. porosity is an essential property of rock due to measure potential storage volume of hydrocarbons. in carbonate reservoir, porosity ranges about 0.01-0.35 (schmoker et al. 1985). in addition, permeability is considered important property of rock because it is measure the ability of rocks to transmit the fluid through it. the permeability value ranges about 0.01 md – over 1 darcy. in general, the reservoir that has 0.1 md value of permeability is considered as minimum ability for oil production and when permeability values in the darcy range, the reservoir consider as highly productive reservoirs ‎[3]. water saturation value which is one of the most difficult aspects of log analysis should be estimated, in order to determine the saturation of hydrocarbons in the formations ‎[4]. yammama formation is the main lower cretaceous carbonate reservoir in southern iraq. it belongs to the late tethonian-aptian cycle. the formation consist of pure limestone, but some dolomitic limestone and shale may exist. yammama formation is the second important unit in the nasiriya field in terms of oil potential. the formation thickness approaches 231m ‎[5]. yammama formation is underlined conformably by sulaiy formation (the uppermost jurassic limestone), and overlained by ratawi formation, which comprises the cap rock for the yammama reservoir. where the ratawi pinches out, the zubair formation directly overlies the yammama. the zubair, ratawi, and yammama formations are periodically coinciding as they are all belonging to the lower cretaceous age ‎[6]. https://doi.org/10.31699/ijcpe.2019.3.8 k. h. jassim and j. a. al-sudani / iraqi journal of chemical and petroleum engineering 20,3 (2019) 59 66 06 yammama formation has been divided into four reservoir units, based on log characteristics and lithology, designated from top to bottom as (ya, yb1,yb2 and yb3), interbeded by three dense layers act as barriers namely (tgt1, tgt2 and tgt3) ‎[5] . the objective of this study is re-evaluation petro physical properties in previous studies. 2petro physical analysis all log curves were then depth-matched. the available deep resistivity log (ild) was taken as reference curve. by using ip software, the environmental corrections were made using the current schlumberger charts on the following logs: rhob, nphi, gr, ild, and msfl. 2.1. shale volume determination shale is fine grain rock consisting sizable fraction of silt & clay. there are many ways to determine the volume of shale in the formation such as from single measurement like gamma ray log or from neutron-density plots ‎[7]. one of the principal uses of gr log is to calculate the volume of shale where it is measuring the natural radiation generated by the formation. most isotopes present naturally in the rocks are stable which present in insignificant amount or generate small amount of radiation. these are the thorium series, the potassium isotope and the uranium-radium isotope. shales are derived from igneous rocks which have amount of radiant isotopes that emit gamma ray. igneous rocks are contained quartz, micas and feldspars and the last two contain adequate amount of potassium and occasionally thorium series and uranium-radium isotopes. the micas and feldspars alter to clay minerals which the last consider the principle component of shales[8]. in the pure carbonate, thorium will usually be not present because the common thorium ions are insoluble, also potassium will be negligible. the rock may involve uranium. uranium indicates material of organic origin as organism is extremely good at storing and concentrating uranium. uranium ions may be soluble or insoluble depending on ions oxidation state. in shaly carbonate rocks, high gamma ray readings aren't attributed to clay fraction may be related to existing of uranium-radium isotope of organically origin. so that thorium and potassium must present together for shale to be indicated. the existing of potassium without thorium (with or without uranium) is indicator of remaining algal mats in the formation. it's better to use computing gamma ray log (cgr), which is only the sum of thorium and potassium radiation, and not total gamma ray in order to estimate shale volume ‎[8]. in previous studies (al-fattal and aboud (2001) ‎[9], omer al-ismaily (2011) ‎[10] and anfal kareem (2013) ‎[11]), they used total gamma ray log for estimating shale volume without looking for spectral gamma ray log that available only for wells ns-3 and ns-5 and shows for these layers an uranium content not negligible, moreover, in some cases, the radioactivity increases in relatively porous layers, conceivably due to the presence of uranium as shown in the fig.1, since the sgr and cgr curves show a significant and not constant separation. thus, the use of the total gamma ray for the wells without sgr log may cause an overestimation of shaliness, and anyway a result not comparable with the others. for these reasons, the vsh was calculated using the density and neutron logs (vsh-dn). the volume of shale from cross plot between neutron-density logs was determined, once clean and clay points are indicated which is calculated as the distance of data lies between the clean line and clay point. fig. 1. well ns-3, yammama formation. sgr log ( )( ) ( )( ) ( )( ) ( )( ) (1) the equation (1) was used by ip software. where: dencl1 and neucl127 and dencl2 and neucl2 are the density and neutron values for the two ends of the clean line as shown in fig. 2 ‎[12]. k. h. jassim and j. a. al-sudani / iraqi journal of chemical and petroleum engineering 20,3 (2019) 59 66 06 cross plot was plotting for five wells in ip software as shown in fig.3 . clean points and clay point was determined for each well as follow: clean point 1 as rho-matrix ranges between 2.68-2.71 g/cm 3 and as nphi-matrix is 0 v/v. clean point 2 as rho-fluid and nphi-fluid are 1. clay point as rho-clay ranges between 2.5 to 2.56 g/cm 3 and as nphi-clay ranges between 0.43-0.45 v/v. the equation (1) was used by ip software. where: dencl1 and neucl127 and dencl2 and neucl2 are the density and neutron values for the two ends of the clean line as shown in fig. 2 ‎[12]. cross plot was plotting for five wells in ip software as shown in fig.3. clean points and clay point was determined for each well as follow: clean point 1 as rho-matrix ranges between 2.68-2.71 g/cm 3 and as nphi-matrix is 0 v/v. clean point 2 as rho-fluid and nphi-fluid are 1. clay point as rho-clay ranges between 2.5 to 2.56 g/cm 3 and as nphi-clay ranges between 0.43-0.45 v/v. fig. 2. neutron / density cross plot [12] fig. 3. density-neutron cross plot for five wells by ip software the results are shown in the fig. 5, 6, 7, 8 and 9 and table 2. 2.2. porosity determination cross plots of density neutron logs are used to determine porosity by using ip software which is correcting automatically density neutron logs for the effect of shale. ip software determines porosity by using the cross-plot or equation 2. the effective porosity is determined by equation .3. √ (2) ( ) (3) after porosity was calculated, it is necessary to calibrate it with core porosity. so for each well, log porosity was plotted against core porosity then the resulting relations were used to calibrate log porosity. the results are shown in the fig. 5, fig. 6, fig. 7, fig. 8, fig. 9 and table 2. 2.3. determination of water saturation water saturation is the fraction volume in a given pore space occupied by a water [4]. it's considering one of the important parameters for estimating oil initial in place. in formation evaluation (petro-physical), water saturation can be estimated from several saturation models depending on whether the reservoir is shaly or clean. in 1942, the first empirical model was building for estimating water saturation in clean, simple, uniform pore system with saline water was archie equation ‎[13] as shown in equation: ( ) (4) water saturation models in shaly formation are the expansion of equation of the archie with the more term which concerned to shale volume and their associated electrical properties. one of this expansion equation is indonesian equation. it was proposed by poupon and leveaux in 1971 which used for estimating effective water saturation in shaly formation that is independent of the shale distribution in the reservoir (bhatt, helle et al.2001). this model shows relationship between the resistivity of formation & the parameters of formation affected it which includes rw, rsh, sw, and vsh as shown by the following equation ‎[14]: (5) k. h. jassim and j. a. al-sudani / iraqi journal of chemical and petroleum engineering 20,3 (2019) 59 66 06 in previous studies, archie equation was used to calculate waster saturation.so, its evidence that overestimate of water saturation because of presence of shale. in these studies, indonesian equation was used to estimate water saturation for five wells. the parameters that used were as following: rsh was applying as 2.05 ohm/m which was derived from thick formation overlying yammama formation. rw was 0.015 ohm/m which was taking from water analysis report. rt was taking from ild log. & vsh was calculated previously. table 1. cementation factor and tortuosity coefficient ‎[9] a m units 1.52 1.44 a 1.48 1.5 b1 1 1.57 b2 1 2.1 b3 the results are shown in the fig. 5, 6, 7, 8 and 9 and table 2. 2.4. permeability estimation permeability is the property of a porous media which is an indication of the ability of porous media to allow fluid to pass through it. in other words, it's considered a measure of ease with that the porous media (rock) will allow the passage of fluids ‎[4]. permeability takes control the displacement of fluids through the pore space of rocks. it is one of the most essential, most spatially variable, most ambiguous & so it least predictable transport properties of reservoir ‎[15]. permeability is commonly calculated from well tests and/or core samples. however, these measurements are not available in all wells in a reservoir but well logs are available in the majority of wells.so that, accurate and credible calculation of permeability from well-log data involves a significant technical and economic advantages ‎[16]. laboratory studies have presented which permeability relies upon many parameters such us: pore size and shape, porosity, pore size distribution, clay content, fluid type, and saturation which is a nearly crushing complexity ‎[17]. permeability is evaluated via correlations among other petro physical properties of rocks. so, various empirical (statistical) models have been introduced to derive permeability from well-log data. the usual approach to estimating permeability is to cross plot core porosity versus log core permeability and obtain a regression line then this relationship is generated to calculate the permeability for each well of the field. unfortunately this assumes that the rock type doesn't change over the interval and permeability is function of porosity only. the method has significant errors but the technique is widely used anyway [7]. permeability determination in carbonate reservoir is a complex problem, due to their capability to be tight and heterogeneous, also core samples are usually only available for few wells therefore predicting permeability with low cost and reliable accuracy is an important issue ‎[18]. also, knowledge of permeability distribution is critical to effective reservoir description. carbonate reservoirs consist of limestone and dolomite; they are generally less homogeneous than clastic reservoirs and have a wide range of grain size distributions. typically carbonates have very low matrix permeability, as low as 0.1 to 1.0 md in some cases, but carbonates often have extensive natural fracture systems ‎[19]. in previous three studies, regression analysis (cross plot) was used to estimate permeability. because of presence of errors in the results in this method which explain above, it was decided to use other method to estimate permeability. fuzzy logic was adopted to predict permeability in this study. fuzzy logic is one of the ways that create predictions from logs. regression methods are fundamental tools of the petro physicist but are weak at predicting extremes. however regression method has the capability to predict and extrapolate values outside the range of the conditioning data-set while fuzzy techniques are confined to look only in the calibrating data-set [20]. in this study, cuddy method was implemented to estimate permeability for yammama reservoir. cuddy achieved fuzzy logic for permeability prediction from well log in ula field, norway. fuzzy probability theory (probability theory and fuzzy set) was used by cuddy to estimate permeability. the 'fuzzy logic curve prediction' module in interactive petro physics (ip) software was used to predict permeability. porosity (nphi, rhob) and volume of shale are best logs to use for permeability prediction. the 'fuzzy logic curve prediction' module uses the mathematics (way) of 'fuzzy logic' as following ‎[20]: the 'input' tab sets up the 'input curve' names to be used to build a 'prediction model'. core permeability, porosity (nphi, rhob) and shale volume curves for ns-2 were used to build model. the 'create model' tab is used to set up the model logic and to create. input curve data are divided into a number of data 'bins' for use in the model. k. h. jassim and j. a. al-sudani / iraqi journal of chemical and petroleum engineering 20,3 (2019) 59 66 06 the number of 'bins' must be between 2 and 100. two types of 'bin sorting' can be applied: 1variable size bins: this is generally used only for discrete input data such as facies numbers. 2equal sampled bins: the program will make a preliminary pass through the input data to calculate the data maxima and minima for all curves. ip will then set the bin spacing's so that an equal proportion of data will be placed in each bin. for each data 'bin' the program calculates the mean (µ) and the standard deviation for all the associated curves to be used in the prediction. to make the prediction, the program first calculates the 'fuzzy probability' that an input log is in a certain bin. the equation is used for this [20]: ( ) √ ( ) ( ) (6) where p(cb): the probability that curve c is in bin 'b'. nb: the number of samples in bin 'b'. c : the input value for curve c. µb : the mean value for curve c for bin 'b'. : the standard deviation for curve c for bin 'b'. the probabilities for all the input curves are then combined as follows: ( ) ( ) ( ) (7) where pb: the total probability for bin 'b'. p (c1b): the probability for curve c1 for bin 'b'. the 'output curves' generated by the model will depend on which 'output result' boxes are checked: 1most likely': the result with the highest probability. 22nd most likely': the result with second highest probability. 3wt. av. 2 most likely': a weighted average of the two most likely results. following equation is used: (8) where: rav: average weighted result rml: most likely result rsl : second most likely result pml: probability of most likely result psl: probability of the second most likely result the result of permeability estimation of ns-2 in yammama formation was shown in fig.4. the average weighted result was taken due of goodness matching between kcore and kav. fig. 4. result log plot from fuzzy logic the 'fuzzy logic curve prediction' module was created for other four wells and it was very good matching between calculated permeability and core permeability. the final results are shown in the fig. 5, fig. 6, fig. 7, fig. 8, fig. 9 and table 2. fig. 5. cpi for ns-1 k. h. jassim and j. a. al-sudani / iraqi journal of chemical and petroleum engineering 20,3 (2019) 59 66 06 fig. 6. cpi for ns-2 fig. 7. cpi for ns-3 fig. 8. cpi for ns-4 fig. 9. cpi for ns-5 k. h. jassim and j. a. al-sudani / iraqi journal of chemical and petroleum engineering 20,3 (2019) 59 66 06 table 2. the result of petro physical properties determination for each well k arith. avg avg. sw avg. ø depth m units wells 0.9 0.152 0.08 3178 3225 ya ns-1 2.06 0.212 0.12 3242 3270 yb1 6 0.24 0.15 3287 3329 yb2 32 0.34 0.16 3363 3415 yb3 1.15 0.12 0.072 3157 3204 ya ns-2 1.9 0.12 0.11 3220 3247 yb1 11 0.20 0.16 3266 3306 yb2 58.2 0.43 0.15 3341 3384 yb3 0.92 0.12 0.065 3177 3222 ya ns-3 1.1 0.25 0.11 3241 3267 yb1 5 0.23 0.14 3287 3327 yb2 3 0.30 0.17 3361 3403 yb3 0.65 0.10 0.071 3166 3213 ya ns-4 3.3 0.22 0.12 3228 – 3257 yb1 8.8 0.24 0.17 3275 – 3317 yb2 9 0.32 0.14 3355 3392 yb3 0.61 0.15 0.06 3168 3215 ya ns-5 3 0.23 0.10 3230 3258 yb1 15 0.21 0.135 3277 3318 yb2 12 0.35 0.16 3358 3389 yb3 3conclusions 1the study comprises log interpretation and petro physical properties calculations by using interactive petro physical software (ip). 2it's evidence that the volume of shale is low in yammama formation because the vsh was calculated by using the density and neutron logs (vsh-dn) due to presence organic material which causes overestimation of shale volume which calculated by gamma ray like in the other studies. 3the porosity for ya unit is considered poor while for yb1and yb2 are fair, but for yb3 is good. 4fuzzy logic was adopted to predict permeability in this study which gives best prediction than linear regression. 5the lower part yammama reservoir (yb2 & yb3) has best reservoir quality. references [1] djebbar tiab and erle c. donaldson, petro physics, book, elsevier, 2 nd edition, 2004. [2] dewhurst, d.n., siggins, a.f., kuila, u., clennell, m.b., elastic, geomechanical and petrophysical properties of shales, statoilhydro research centre, trondheim, norway, 2008. [3] ekwere j. peters, “petrophysics”, department of petroleum and geosystems engineering. the university of texas, austin, 2000. [4] tarek ahmed, reservoir engineering handbook, book, elsevier, fourth edition, 2010. [5] oec, "an integrated geological evaluation study of the nasiriyah field", (in arabic), baghdad, 1993. [6] repsol, “technical analysis – business development – upstream" madrid, october– 2008. [7] e. r. crain. the log analysis handbook, pennwell books, 1986. [8] hongqi liu, principles and applications of well logging, book, springer, 2017. [9] al-fattal and aboud, a comprehensive reservoir study of nasiriya field/ yammama formation, ministry of oil, reservoir and field development department, 2001. [10] omer al-ismaily, study of reservoir properties of yamama formation in nassirya field and its relation with oil production, thesis, the college of science, university of basra, 2011. [11] anfal kareem, reservoir study of yammama formation in nasiriya field by using modern software, thesis, petroleum engineering, baghdad university, 2013. [12] schlumberger, "interactive petrophysical fundamental, version 3.1", 2005. [13] archie, g. e., the electrical resistivity log as an aid in determining some reservoir characteristics. petroleum transactions of the aime, 1942. [14] poupon, a. and leveaux, j., evaluation of water saturation in shaly formations. the log analyst, 12, 1-2, 1971. [15] w. al-qattan and a. al mohammed, “permeability prediction by classical and flow zone indictor (fzi) methods for an iraqi gas field”, ijcpe, vol. 18, no. 3, pp. 59-65, sep. 2017. [16] s. ameri, d. molnar, s. mohaghegh, and k. aminian. permeability evaluation in heterogonous formations using geophysical well logs and geological interpretations. in spe western regional meeting, anchorage, alaska, 1993. [17] schlumberger. log interpretation principles/applications. houston, 1989. [18] d. alobaidi, “permeability prediction in one of iraqi carbonate reservoir using hydraulic flow units and neural networks”, ijcpe, vol. 17, no. 1, pp. 1-11, mar. 2016. [19] s. a. lazim, s. m. hamd-allah, and a. jawad, “permeability estimation for carbonate reservoir (case study/ south iraqi field)”, ijcpe, vol. 19, no. 3, pp. 41-45, sep. 2018. [20] cuddy, s. j. , the application of the mathematics of fuzzy logic to petro physics. paper s. 38th annual symposium of the spwla, 1997. https://www.onepetro.org/conference-paper/arma-08-208 https://www.onepetro.org/conference-paper/arma-08-208 https://www.onepetro.org/conference-paper/arma-08-208 https://www.onepetro.org/conference-paper/arma-08-208 https://www.elsevier.com/books/reservoir-engineering-handbook/ahmed/978-1-85617-803-7 https://www.elsevier.com/books/reservoir-engineering-handbook/ahmed/978-1-85617-803-7 https://www.osti.gov/biblio/5563453 https://www.osti.gov/biblio/5563453 https://link.springer.com/chapter/10.1007/978-3-662-54977-3_8 https://link.springer.com/chapter/10.1007/978-3-662-54977-3_8 https://www.onepetro.org/journal-paper/spwla-1971-vxiin4a1 https://www.onepetro.org/journal-paper/spwla-1971-vxiin4a1 https://www.onepetro.org/journal-paper/spwla-1971-vxiin4a1 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/66 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/66 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/66 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/66 https://www.onepetro.org/conference-paper/spe-26060-ms https://www.onepetro.org/conference-paper/spe-26060-ms https://www.onepetro.org/conference-paper/spe-26060-ms https://www.onepetro.org/conference-paper/spe-26060-ms https://www.onepetro.org/conference-paper/spe-26060-ms http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/85 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/85 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/85 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/85 https://doi.org/10.31699/ijcpe.2018.3.5 https://doi.org/10.31699/ijcpe.2018.3.5 https://doi.org/10.31699/ijcpe.2018.3.5 https://doi.org/10.31699/ijcpe.2018.3.5 https://www.onepetro.org/conference-paper/spwla-1997-s https://www.onepetro.org/conference-paper/spwla-1997-s https://www.onepetro.org/conference-paper/spwla-1997-s k. h. jassim and j. a. al-sudani / iraqi journal of chemical and petroleum engineering 20,3 (2019) 59 66 00 اعادة تقييم الخواص البتر وفيزيائية لتكوين اليمامة في حقل الناصرية كرار حيدر و جالل عبدالواحد قسم ىندسة النفط/جامعة بغداد الخالصة اليمامة تعد من التكوينات تكوينكم. ان 83غرب مدينة الناصرية بحوالي -يقع حقل الناصرية النفطي شمال الكربونية االساسية من العصر الطباشيري االسفل في جنوب العراق. قسم تكوين اليمامة الى اربع مكامن وىي ya,yb1,yb2,yb3 .وىذه المكامن تفصل بينيا طبقات عازلة مختمفة السمك تعتبر من ةيم الخواص البتر وفيزيائياليمامة في حقل الناصرية. ان دقة تقي تكوينعمى ال تثالثة دراسات اجري حجم الطفل والمسامية وتشبع المائي ) اىم االمور لبناء موديل جيولوجي لذلك تم اعادة تقييم الخواص األربعة كاما لحساب حجم الطفل بدون االخذ بنظر االعتبار اشعة . في الدراسات السابقة تم استخدام مجس (والنفاذية المتوفر لبئر ناصريو الثالث والخامس حيث تبين وجود طبقات تحمل بيعياشعة كاما الط تسجيل مجس . تم حساب المسامية من ipجبرنام ماليورانيوم لذلك تم حساب حجم الطفل من مجس الكثافة والنيوترون باستخدا مباستخدامجس الكثافة والنيوترون المصححة لتأثير الطفل. ايضا في الدراسات السابقة تم حساب التشبع المائي بدون االخذ بنظر االعتبار الزيادة الحاصمة في قيم التشبع نتيجة تأثير حجم الطفل. تم استخدام archieمعادلة ايضا تم استخدام منطق الضباب لحساب النفاذية عكس الدراسات لحساب تشبع المائي. امعادلة إندونيسي قميل الدقة. تحميل االنحدارالسابقة التي تم استخدام الكممات الدالة: حجم الطفل، المسامية، التشبع المائي، النفاذية، منطق الضباب. iraqi journal of chemical and petroleum engineering vol.16 no.1 (march 2015) 112 issn: 1997-4884 performance of corrosion inhibitors blend for simulated industrial cooling waters under dynamic conditions qasim j.m.slaiman and abeer a. al-khasab department of chemical engineering, college of engineering, al-nahrain university, iraq abstract the inhibitive action of a blend of sodium nitrite/sodium hexametaphosphate (sn+shmp) on corrosion of carbon steel in simulated cooling water systems (cws) has been investigated by weight loss and electrochemical polarization technique. the effect of temperature, velocity, and salts concentrations on corrosion of carbon steel were studied in the absence and presence of mixed inhibiting blend. also the effect of inhibitors blend concentrations (sn+shmp), temperatures, and rotational velocity, i.e., reynolds number (re) on corrosion rate of carbon steel were investigated using second-order rotatable design (box-wilson design) in performing weight loss and corrosion potential approach. electrochemical polarization measurements were used to study the behavior of carbon steel in different salts concentrations of (cws) with ph = 7.5 in absence and presence of the inhibiting blend. the results show that the regression model (box-wilson design) that has been developed using experimental data was used to verify that the interaction term of temperature with inhibitors blend and the square term of inhibitors blend are significant for corrosion rate in 0.05 n nacl solution while the main variables are not pronounced. also, it is found that the corrosion rate of carbon steel is increased with increasing temperature, rotational velocity, and nacl salts concentration in uninhibited and inhibited solutions. inhibition performance of nano2+ na(po3)6 was found to increase with its concentration up to 800 ppm inhibitors blend, and the corrosion potential is shifted to more positive direction with increasing rotational velocity, and inhibitor blend concentration. key words: corrosion inhibitors, cooling water systems, sodium hexametaphosphate, rotatable design (box-wilson design). introduction understanding the effect of environmental factors is necessary in determining the rate of a metal corrosion. each metal species will exhibit its own rate of corrosion. environmental factors such as oxygen concentration, ph, chloride ion concentration and temperature are also known to influence the rate of corrosion [1]. therefore, there is a need to protect these metals against corrosion. the best option available for the protection of metals against corrosion has been found to be using of inhibitors [2]. cooling water systems are integral part of most industries and their performance is seriously affected iraqi journal of chemical and petroleum engineering university of baghdad college of engineering performance of corrosion inhibitors blend for simulated industrial cooling waters under dynamic conditions 2 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net by corrosion of materials and scale deposits. use of inhibitors in controlling corrosion/scales in cooling water systems is an established technology. a number of inorganic/organic inhibitors have been used in the last sixty years [3]. corrosion inhibitors retard the destruction of metals by chemical or electrochemical reactions with their environment. most of the inhibitors used in cooling waters, are either alone or in combination with one or more corrosion inhibitors [4]. most of inorganic inhibitors are toxic e.g., chromate, mercuride nitrite, arsenate etc. [5]. as a result, the current trend for inhibitor usage towards more environmentally friendly ‘green’ chemicals [6]. the aim of this work is to study the performance of corrosion inhibitors blend action of sodium nitrite / sodium hexametaphosphate on carbon steel rotating cylinder in different salt concentrations of cooling water systems at different temperatures (30, 45,& 60 ◦c) under dynamic conditions of different velocities (200,600, & 1000 rpm). experimental method materials cylindrical carbon steel specimen was prepared to fit the specimen holder with a surface area of 19.6350 cm 2 having dimensions of 2.5 cm long (l), 1.9 cm inside diameter (di), and 2.5 cm outside diameter (do) that were measured using electronic digital caliper. its composition is given in table (1): table (1), the chemical composition of carbon steel cylinder (wt. %). mn v cr mo fe 0.06 0.93 0.05 3.51 0.35 balanc e solutions four different tested solutions (un inhibited solutions) were prepared by dissolving four different concentrations of nacl salt with 0.00736 n na2so4 in one litter of distilled water at ph of 7.5: a. 0.005 n nacl + 0.00736 n na2so4 b. 0.01 n nacl + 0.00736 n na2so4 c. 0.03 n nacl + 0.00736 n na2so4 d. 0.05 n nacl + 0.00736 n na2so4 inhibitors solutions were prepared by dissolving appropriate amounts of inhibitors as a blend of sn and shmp in each tested solutions based on total ppm made of the two inhibitors as shown below: e. 0.005 n nacl + 0.00736 n na2so4 + 600 ppm (500 sn+100 shmp). f. the same tested solution b with two different concentrations of each inhibitor [600 ppm (sn+ shmp)]. g. the same tested solution c with two different concentrations of each inhibitor [600 ppm (sn+ shmp)]. h. the same tested solution d with different amounts of inhibitors blend according to box-wilson method [7]. the ph of the solution was adjusted using dilute solutions of naoh or hcl. weight loss method the metal specimens were abraded with glass emery paper of grades, 120, 180, 220, 400 and 2000 respectively, washing continuously with running tap water followed by distilled water, dried with kleenex tissue, rinsed with acetone, followed by ethanol, dried with kleenex tissue and left in qasim j.m.slaiman and abeer a. al-khasab -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 3 desiccator for 20 hours, and then weighed accurately before using or introduced in the tested solutions. after test the specimens were visually observed, then washed with running tap water, cleaned with brush to remove the weakly adherent corrosion scale, washed with distilled water, swabbed with a piece of cotton soaked with inhibited hydrochloric acid to remove all adherent corrosion products, washed with running tap water, and then repeat the cleaning as in the beginning then left for 20 hour to dry in a desiccator over silica gel, and accurately weighed to the forth decimal of gram. polarization technique the electrochemical cell was composed of graphite counter electrode, prepared carbon steel specimen as working electrode and saturated calomel electrode (sce) as a reference electrode. corrosion potential (ecorr.) and polarized potential were measured against sce. corrosion cell parts (see fig. 1) were then connected to ammeter and voltmeter. cathodic polarization was performed until reaching the corrosion potential, then continuing with anodic polarization. the potential was changed (30-50 mv) for each step and after one minute period steady state current was recorded for each potential step. also, it is to be stated that the experimental runs were repeated twice to four times to ensure accuracy and repeatability. fig.1, corrosion-cell parts 1. graphite electrode (anode), 2.rotating shaft (holder), 3.working electrode (specimen), 4.beaker, 5.water bath, 6.reference saturated calomel electrode (sce), 7.stirrer, 8.power supply, 9.resistance box, 10.voltmeter, 11. ameter, 12. luggin capillary tip, 13.brush, 14.thermometer, 15.electrical wires results and discussion 1. weight loss method a. uninhibited solutions fig. 2, the relation between corrosion rate and reynolds no. at different temperatures for 4 h immersion time. 0 20 40 60 80 100 120 140 0 20000 40000 60000 c o r r o si o n r a te i n g m d re cr (gmd), t=30◦c cr (gmd),t=45◦c cr (gmd), t=60◦c 1 2 3 1 2 1 4 9 4 5 6 7 8 1 0 1 1 1 3 1 5 performance of corrosion inhibitors blend for simulated industrial cooling waters under dynamic conditions 4 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net fig. (2), shows the variation of corrosion rate of carbon steel in 0.05 n nacl for three different temperatures (30, 45, and 60 o c) with corresponding values of reynolds number (based on the outer diameter of the specimen) for an immersion period of 4 h and ph of 7.5. it is clear that from fig. (2) increasing the flow velocity leads to an increase in the corrosion rate for a given temperature. this can be attributed to the increase in the transport rate of oxygen to the metal surface by eddy transport. the rate of oxygen reduction reaction is generally limited by the rate at which oxygen can reach the surface of the metal. also, it is clear that corrosion rate increases with increasing temperature at a given velocity. the effect of temperature on corrosion rate for mass transfer controlled systems is dictated by two parameters which affect corrosion rate in conflicting ways that are decreased o2 solubility and increased o2 diffusivity. increasing the temperature will increase the rate of oxygen diffusion to the metal surface by decreasing the viscosity of water and enhancing the corrosion rate. fig. (3) shows the variation of corrosion rate of carbon steel with nacl concentration of (0.05, 0.03, 0.01, 0.005 n) at 60 o c, and 1000 rpm for immersion time of 4 h. fig. 3, the relation between corrosion rate and nacl concentration for immersion time of 4 hr. it is seen from fig. (3) that increased concentration of nacl salts leads to an increased corrosion rate of carbon steel. this is due to an increase in the conductivity of the solution. chlorides increase the electrical conductivity of water so that the flow of corrosion currents will be facilitated [8, 9]. b. inhibited solutions table (2) displays the low and high levels factor variation interval, the matrix of the central composite rotatable design (ccrd) executed in 0.05 n nacl (solution d) as given in table (3). table (2), factor variation interval of central composite rotatable design 0 50 100 150 0 0.05 0.1 c o r r o si o n r a te ( g m d ) nacl concentration (n) 60 ◦c, 1000 rpm factors variation levels var iation inte rval s 1.68 2 -1 0 1 1.6 82 ∆x x1, tempera -ture ( 0 c) 30 36 45 54 60 15 x2, velocity (rpm) 200 362 600 83 8 10 00 400 x3, inhibitor s blend concentr ation (sn+sh mp) (ppm) 600 640 700 76 0 80 0 100 500 + 100 520 + 120 550 + 150 58 0 + 18 0 60 0 + 20 0 50 50 qasim j.m.slaiman and abeer a. al-khasab -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 5 table (3), design matrix of the central composite rotatable design (ccrd) number of experim ents temperat ure,(◦c) veloc ity, (rpm) inhibitor blend concentr ation,(pp m) (sn+sh mp) x3 corrosio n rates x1 x2 (gmd) 1 1 1 1 1.222 2 1 1 -1 5.653 3 1 -1 1 2.597 4 1 -1 -1 2.903 5 -1 1 1 3.972 6 -1 1 -1 2.292 7 -1 -1 1 3.361 8 -1 -1 -1 1.069 9 -1.68 0 0 1.528 10 1.68 0 0 2.750 11 0 -1.68 0 2.139 12 0 1.68 0 2.445 13 0 0 -1.68 1.833 14 0 0 1.68 0.764 15 0 0 0 3.361 16 0 0 0 3.056 17 0 0 0 3.667 18 0 0 0 4.278 19 0 0 0 3.667 20 0 0 0 3.972 the results of corrosion rate have been analyzed as optimization criterion. the linear model obtained after the eight design points was inadequate. full fractional experimental (fufe) design has therefore been upgraded based on a second-order rotatable design. regression coefficients were determined from experimental data for the following regression equation of corrosion rates by minitab 16 computer program. carbon steel corrosion rate is analyzed as function of three variables: temperature, velocity, and inhibitors blend concentrations. all terms regardless of their significance are included in the following equation for 0.05 n nacl. ……….. (1) where y is the response, that is corrosion rate of carbon steel, and x1, x2, and x3 are the coded values of the test variables, i.e., temperature, rotational velocity, and (sn+shmp) inhibitors blend’s concentration respectively. according to equation (1): 1. the main factors are temperature, and rotational velocity which have positive effects on corrosion rate (i.e., increases corrosion rate). keeping in mind that temperature is a little more pronounced compared to rotational velocity in affecting carbon steel corrosion rate. 2. the other main factors are (sn+shmp) inhibitors blend concentration, showed a negative effect (i.e., decreases corrosion rate). fig. (4) displays corrosion rate of carbon steel in three different concentrations of nacl with and without the addition of 600 ppm inhibiting blend (500 ppm sn + 100 ppm shmp) at 60 o c and 1000 rpm for an immersion time of 4 h at ph of 7.5 using weight loss method. performance of corrosion inhibitors blend for simulated industrial cooling waters under dynamic conditions 6 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net fig 4, the relation between corrosion rate of carbon steel and nacl concentration of with and without addition of 600 ppm inhibitors blend for immersion time of 4 h. figure (4) shows that the corrosion rate at 60 o c and 1000 rpm for the three concentrations (0.005, 0.01, and 0.03 n nacl) decreases markedly with the addition of inhibitors blend, and this proves the highly inhibitive performance of this blend (sn+shmp) at higher temperature and velocity (i.e., under dynamic conditions). table (4) shows the efficiency of the inhibiting blend (600 ppm) in the three different concentrations of nacl. table (4), efficiencies of the inhibiting blend (600 ppm) in three concentrations of nacl at 60 o c and 1000 rpm concentration (n) cr (gmd) with inhibitor cr (gmd) without inhibitor efficiency % 0.005 1.5279 102.37 98.5 0.01 2.4446 109.7 97.8 0.03 3.9724 120.4 96.7 2. corrosion kinetic parameter (activation energy) in general, the rate of most chemical reactions increases with temperature following arrhenius equation [10]. temperature favors the kinetics of corrosion reactions and more specifically, the anodic dissolution of the metal. the activation energy of the corrosion process can be obtained from the plots of arrhenius according to the following equation: ……... (2) where ea is the activation energy of the process (j/mol), r is the universal gas constant (8.314 j/(mol.k)), t is the temperature (k) and a is a constant. taking the logarithm of the arrhenius equation yields: ( ) ………(3) the values of activation energy of corrosion in 0.05 n nacl can be determined from the slope of log (corrosion rate) versus 1/t plots. fig.5, arrhenius plots of carbon steel in 0.05 n nacl, uninhibited solution. actual values of activation energy for each case of carbon steel corrosion with different temperatures, 30, 45 & 60 ◦c and rotational velocities, i.e., static, 200, 600, and 1000 rpm were plotted according to eq.3 in fig. 5. from the gradient of the plotted curves, the calculated ea values are listed in table (5). 0 20 40 60 80 100 120 140 0 0.02 0.04 c o r r o si o n r a te ( g m d ) nacl concentration (n) cr without inhibitor cr with 600 ppm (sn+shmp) 0 0.5 1 1.5 2 2.5 0.0028 0.003 0.0032 0.0034 l o g ( c o r r o si o n r a te ) g m d 1/t (k-1) static 200 rpm qasim j.m.slaiman and abeer a. al-khasab -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 7 table (5), activation energy values at different rotational velocities i.e., re number. velocity (rpm) ea (kj/mol) log a static 8.152 2.462 200 24.37 5.581 600 37.59 7.926 1000 42.99 8.909 the activation energy of an electrochemical process refers to the energy level that must be overcome by one electron in the exchange through the interphase between electrode and electrolyte. results revealed the activation energy values of the reaction increased with increasing values of rotational velocity. however, rising of temperature acts in the reverse direction due to its duel influence on o2 dissolved concentration and diffusion coefficient as stated above. fig.6 presents arrhenius plots in absence & presence of 700 ppm inhibiting blends for 600 rpm (center condition of rotatable design, i.e., run 9, 10, and 15), which reveal that the activation energy decreases to a value of 16.84 kj/mol. fig.6, arrhenius plots for carbon steel corrosion in 0.05 n nacl, in absence and presence of 700 ppm (550 sn+150 shmp) inhibitors blend. 3. polarization technique electrochemical polarization cell was composed of graphite counter electrode, carbon steel specimen as working electrode and saturated calomel (sce) as a reference electrode. a. corrosion potential corrosion potential measurements were carried out for selected conditions of 0.05 n nacl solutions and also in the other three concentrations (salts concentrations) in absence and presence of corrosion inhibitors blend. figs. (7) and (8) show the corrosion potential curves vs. time in 0.05 n nacl salts solution at three different temperatures (30, 45, and 60 ◦c) and different velocities, i.e., (experiments 9-15) of rotatable design. fig. (8) presents the results for the three different concentrations (0.005, 0.01, 0.03 n nacl) in the absence and presence of inhibitors blend for 4 h immersion time. fig.7, the relation between corrosion potential and time of carbon steel rotating cylinder in 0.05 n nacl + 0.00736 n na2so4 at different temperatures and velocities in absence 0 0.5 1 1.5 2 2.5 0.0028 0.003 0.0032 0.0034 lo g ( c o r r o si o n r a te ) g m d 1/t (k-1) 600 rpm -600 -500 -400 -300 -200 -100 0 0 100 200 300 p o te n ti a l (m v ) time (min) 30 ◦c, 600 rpm 45 ◦c, 200 rpm 45 ◦c, 600 rpm 45 ◦c, 1000 rpm 60 ◦c, 600 rpm 30◦c, 600 rpm, 700 ppm (sn+shmp) 45 ◦c, 200 rpm, 700 ppm (sn+shmp) 45 ◦c, 600 rpm, 700 ppm (sn+shmp) 45◦c, 1000 rpm, 700 ppm (sn+shmp) performance of corrosion inhibitors blend for simulated industrial cooling waters under dynamic conditions 8 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net and presence of 700 ppm (550 sn+150 shmp) for 4 h immersion time, and ph of 7.5. fig.8. corrosion potential vs time of carbon steel rotating cylinder in 0.05 n nacl + 0.00736 n na2so4 at 45◦c, and 600 rpm with three concentrations of inhibiting blend (600,700, and 800 ppm) for 4 h immersion time at ph of 7.5. fig. 9, the relation between corrosion potential vs time of carbon steel rotating cylinder in three different concentrations of nacl salts solution at 60 0 c, and 1000 rpm, with and without the presence of 600 ppm inhibitors blend for 4 h immersion time, ph = 7.5. it is clearly seen from figs. (7) through (9) that the corrosion potential for all salts concentrations of nacl in absence of inhibitors blend (i.e., sn+shmp) decreases rapidly with time and finally reaches a steady state value. this variation of corrosion potential with time reveals the corrosivity of water on carbon steel. however, in presence of corrosion inhibitors blend (sn+shmp), the steady state potential is shifted more towards noble direction by increasing the concentration of inhibiting blend and temperature. such noble shift of corrosion potential in the range of about 100 to 300 mv would indicate possibly the mechanism of passivation to protect carbon steel in the present aqueous solutions of sodium salts. in addition, a more noble shift illustrates increased anodic polarization for the protection of the metal, i.e., the inhibitors blend is anodically and passively effecting the protection of carbon steel in the present temperature range under dynamic conditions. b. electrochemical polarization studies electrochemical polarization studies were performed for selected points of the rotatable design of 0.05 n nacl, (experiment 9 to 15). the polarization behavior of carbon steel in simulated cooling water in presence and absence of inhibitors blend in 0.05 n nacl are shown in fig. (10) through (12) respectively, according to the effect of velocity, temperature, and inhibitors blend concentration. fig. (13) shows the polarization curves for the other three concentrations of nacl salt (0.005, 0.01, and 0.03 n nacl): -600 -500 -400 -300 -200 -100 0 0 100 200 300 p o te n ti a l (m v ) time (min) 45 ◦c, 600 rpm 45 ◦c, 600 rpm, 600 ppm (sn+shmp ) -600 -500 -400 -300 -200 -100 0 0 100 200 300 p o te n ti a l (m v ) time (min) 0.005 n nacl 0.01 n nacl 0.03 n nacl 0.005 n nacl+ 600 ppm (sn+shmp ) qasim j.m.slaiman and abeer a. al-khasab -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 9 fig.10, polarization curves of carbon steel in absence and presence of 700 ppm (550 sn+150 shmp) inhibitor blend at 45 ◦c and different velocities (run 11, 12 and 15). fig. 11, polarization curves of carbon steel in absence and presence of 700 ppm (550 sn+150 shmp) inhibitor blend at 600 rpm and different temperatures (run 9, 10, and 15). fig. 12, polarization curves of carbon steel in absence and presence of different concentrations of inhibitors blends for the central temperature and velocity. fig. 13 polarization curves of carbon steel in different concentrations of nacl, in absence and presence of 600 ppm (500 sn+100 shmp) inhibitors blend at 60 0 c and 1000 rpm. the polarization curves of fig. (10) and (11) show that the limiting current density is increased with increasing temperature at a constant rpm. also at a constant bulk temperature the -1700 -1200 -700 -200 300 800 0.001 0.01 0.1 1 10 p o te n it a l (m v ) v s s c e log i (ma/cm2) 45 , 200 rpm 45 , 600 rpm 45 , 1000 rpm 45 , 200 rpm, 700 ppm (sn+shm p) 45 , 600 rpm, 700 ppm (sn+shm p) 45 , 1000 rpm, 700 ppm (sn+shm p) -1700 -1200 -700 -200 300 800 0.001 0.1 10 p o te n ti a l (m v ) v s s c e log i (ma/cm2) 30 , 600 rpm 45 , 600 rpm 60 , 600 rpm 30 , 600 rpm, 700 ppm (sn+shmp ) 45 , 600 rpm, 700 ppm (sn+shmp ) -1800 -1300 -800 -300 200 700 0.001 0.1 10 p o te n ti a l (m v ) v s. s c e log i (ma/cm2) 45 c, 600 rpm 45 c, 600 rpm, 600 ppm (sn+shmp) 45 c, 600 rpm, 700 ppm (sn+shmp) 45 c, 600 rpm, 800 ppm (sn+shmp) -1800 -1300 -800 -300 200 700 0.001 0.1 10 p o te n ti a l (m v ) v s s c e log i (ma/cm2) 0.005 n nacl 0.01 n nacl 0.03 n nacl 0.005 n nacl, 600 ppm (sn+shmp ) 0.01 n nacl, 600 ppm (sn+shmp ) 0.03 n nacl, 600 ppm (sn+shmp ) performance of corrosion inhibitors blend for simulated industrial cooling waters under dynamic conditions 10 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net limiting current density increases with increasing rpm in both inhibited and uninhibited solution. the increase in rpm may act to erode any formed layer, increase the metal ion transfer from the metal surface to the solution and the oxygen diffusion from the solution to the metal surface. in contrast, at a constant rpm, the limiting current density is increased with increasing bulk temperature that its effect causes stimulation of the anodic dissolution of iron. tables (6) and (7) illustrate the values of corrosion current (icorr.), limiting current densities of dissolved oxygen (il), and corrosion potentials (ecorr.) for 0.05 n nacl solution in absent and presence of the inhibiting blends (run 9 to 15 as selected from the rotatable design). tables (7) and (8) illustrate the values of (icorr.), (il) and (ecorr.) for the others three different concentration of nacl solutions at 60 o c and 1000 rpm (re of 69031). table (6), values of (icorr.), (il) and (ecorr.) for 0.05 n nacl solution table (7), values of (icorr.), and (ecorr.) for 0.05 n nacl solution with the addition of different concentrations of inhibitors blend according to ccrd run no. temp. rpm re icorr (ma/cm 2 ) il (ma/cm 2 ) ecorr. ( o c) (mv) 9 30 600 24499 0.1 0.17 -320 10 60 600 41419 0.3 0.43 -390 11 45 200 10799 0.198 0.29 -394 12 45 1000 53996 0.29 0.4 -340 15 45 600 32398 0.24 0.33 -350 run no. temp. rpm re inhibitors blend concentration (sn+shmp) (ppm) icorr (ma/cm 2 ) ecorr. ( o c) (mv) 9 30 600 24499 700 (550+150) 0.012 -120 10 60 600 41419 700 (550+150) 0.022 -150 11 45 200 10799 700 (550+150) 0.016 -224 12 45 1000 53996 700 (550+150) 0.02 -140 13 45 600 32398 600 (500+100) 0.039 -192 14 45 600 32398 800 (600+200) 0.018 -135 15 45 600 32398 700 (550+150) 0.023 -144 qasim j.m.slaiman and abeer a. al-khasab -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 11 table (8), values of (icorr.), (il) and (ecorr.) for the different concentrations of nacl at 60 o c and 1000 rpm (re = 69031) nacl concentration (n) icorr. il ecorr. (ma/cm 2 ) (ma/cm 2 ) (mv) 0.005 0.29 0.37 -320 0.01 0.36 0.47 -325 0.03 0.45 0.52 -340 table (9), values of (icorr.), and (ecorr.) for the different concentrations of nacl solutions with the addition of 600 ppm (500 sn+100 shmp) inhibitors blend at 60 o c and 1000 rpm (re = 69031) nacl concentration (n) icorr ecorr. (ma/cm 2 ) (mv) 0.005 0.03 -110 0.01 0.04 -100 0.03 0.05 -130 the formulated inhibitor blend contains sodium nitrite as an anodic inhibitor and sodium hexametaphosphate as a cathodic inhibitor. the corrosion potential values of carbon steel at the various flow rates and temperatures are shifted to more noble direction, due to the fact that nano2 is an anodic inhibitor [11]. furthermore, (napo3)6 acts as cathodic inhibitor [12] is expected to shift the potential strongly towards a negative value. thus, the net shift of corrosion potential using the present blend is to be in the more noble direction in order to reduce corrosion of carbon steel. conclusions 1. corrosion rate of carbon steel is increased with increasing the temperature range from 30 o c to 60 o c, rotational velocity from 200 to 1000 rpm, and nacl salts concentration in uninhibited and inhibited solution. 2. corrosion rate decreases with increases in inhibitors blend concentrations up to 800 ppm for 0.05 n nacl. while 600 ppm inhibitors blend concentration are very good concentration to give a high efficiency of 98.5%, 97.7%, and 96% for 0.005, 0.01 and 0.03 n nacl. 3. corrosion potentials are shifted to the more positive direction with increasing rotational velocity, and inhibitor concentration. 4. the presence of sodium nitrite is very important with sodium hexametaphosphate to protect inhibit carbon steel in the presence of oxygen. 5. the blend of (sn+shmp) shows excellent efficiencies for almost all concentrations of cooling water systems under a range of flow and temperature conditions. 6. references references 1. webster k. sue, “effects of nacl concentration and temperature on corrosion: understanding material interactions in aqueous environments”, boston university performance of corrosion inhibitors blend for simulated industrial cooling waters under dynamic conditions 12 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net school of medicine, m.sc. thesis, 2010. 2. eddy n.o., ekwumemgbo p.a., mamza p.p., “ethanol extract of terminalia catappa as green inhibitor for the corrosion of mild steel in sulfuric acid”, green chem. let. rev. 2(4), 223-231. 3. farooqi i.h., p.a.saini, and m. a. quraishi, “recent trends in cooling water lnhibitors”, corrosion, 2000. 4. eswaran m.s., mathar p.k.,“physico-chemical evaluation of corrosion inhibitor for carbon steel used in the cooling water system”, corrosion science, vol.38, pp.1783-1790, 1996. 5. hinton, brw, met. finish, vol.89, pp. 55, 1991. 6. lake d.l., “approaching environmental acceptability in cooling water corrosion inhibition, corrosion prevention and control, 1998, p.113. 7. ivorad z., r. lazic´, “design of experiments in chemical engineering”, wiley-vch verlag gmbh & co. kgaa, weinheim, usa, 2004. 8. revie r.w. and h.h. uhlig, “corrosion and corrosion control an introduction to corrosion science and engineering” fourth edition, john wiley &sons, inc., hoboken new jersey, 2008. 9. shreir l.l., r.a. jarman and g.t. burstein, “corrosion metal / environment reactions” third edition, butterworth-heinemann volume i, great britain, 2000. 10. astm g1-3, standard practice for preparing, cleaning, and evaluating corrosion test specimens. 11. joseph c.l., proc.third eur. symp. inhib., 1970, 19, 791. 12. rosenfield i.l., “ corrosion inhibitor “ , mcgraw hill , new york , 1981 . 13. marshall a., “corrosion inhibitor for use in natural water system “ london , oyez scientific and service ld,1983 . 14. cohan m., corrosion sci. , 1976, 4, 46. iraqi journal of chemical and petroleum engineering vol.18 no.1 (march 2017) 99 110 issn: 1997-4884 experimental study for commercial fertilizer npk (20:20:20+te n: p: k) in microalgae cultivation at different aeration periods mahmood k. h. al-mashhadani and entisar mohsin khudhair chemical engineering department, college of engineering, university of baghdad email: mkh_control@yahoo.com and entisar. mohsen@gmail.com abstract recently, microalgae have become a promising source in the production of biofuel. however, the cost of production is still the main obstacle to develop of this type of source. although there are many extensive studies on the requirements provided for the cultivation of the microalgae, the study of the process, via the variables that affect the cultivation of microalgae, being still one of the important tasks to improve the production of biofuel. the present article is a serious attempt to investigate of use commercial fertilizer npk (20:20:20+te n: p: k) as considered a cheap nutrient medium in growth chlorella vulgaris by comparison with traditional nutrient (chu.10 medium). in addition, the current study addresses effect of different sparging periods of filtered air on the microalgae production. the experimental data showed that the use of the npk fertilizer as cultivation medium in chlorella vulgaris culture gives more growth rate of microalgae than that produced if the cultivation process was operated with chu.10 medium. for example the maximum biomass concentration reaches to 0.3249 g l -1 when cultivated in npk fertilizer, whereas reached to 0.212 g l -1 for cells cultivated in chu.10 medium. in addition, the results proved that the aeration system in the cultivation can plays an important role in the activity of the microalgae with npk medium, since it creates a convenient environment with low concentration of oxygen in the medium. the study showed that increasing aeration period for such a type of microalgae increases the growth rate. key words: microalgae, chlorella vulgaris, npk, aeration. introduction environmental and economic challenges are still facing the world due to use of fossil fuels as a main source of energy. the fluctuating rates in the prices as well as reaching the global thermal gases concentration to critical levels, has push the researches to find alternatives to this source [1-6]. numerous attempts have been made to mitigate greenhouse gases, including physical and chemical substance reaction-based co2 mitigation, however; these methods are either consumer of energy dramatically or unconvincing economically [7, 8]. biological treatments for fixing the greenhouse gases may be the best solution so far, such as carbon dioxide consumption by microalgae as a source of carbon and to adjust ph value [9]. university of baghdad college of engineering iraqi journal of chemical and petroleum engineering mailto:mkh_control@yahoo.com mailto:entisar.%20mohsen@gmail.com experimental study for commercial fertilizer npk (20:20:20+te n: p: k) in microalgae cultivation at different aeration periods 100 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net this types of plants have ability for co2 biofixation efficiently by converting it (with light) into biomass and other secondary metabolites such as carbohydrates, lipids, chemicals, foods, feed , intracellular polysaccharides, proteins, pigments and other feed stock [10, 11]. also, the microalgal has a higher photosynthetic efficiency, higher biomass production, faster growth related to other energy crops and they can grow anywhere without competing food crop [12-14]. moreover, they need just few days to complete their growth cycle and their reproduction significantly [15]. there are an extensive attempts on the requirements provided for the cultivation of the microalgae, however; still needed to more studied by voice variables that affect directly or indirectly on the cultivation. the present study is one of these attempts to find the most favorable conditions to secure reasonable growth rate and biomass productivity for chlorella vulgaris via the suggested hypothesis that says that uses a commercial fertilizer 20:20:20+te npk, as low cost nutrient and available, under aeration at different sparging periods can play an important role growth rate and productivity of chlorella vulgaris. material and methods microorganism and culture medium chlorella vulgaris was suggested as a microalga for this investigation, which belongs to the chlorophyta group (freshwater green algae). this spece was originally isolated and purified at plant laboratory for graduate studies, department of biology, college of science, university of baghdad by using serial dilution then different plating techniques as spread and streak method were carried out to purify the culture [16]. as shown in figure 1 the snapshot of chlorella vulgaris used in the present study using microscope (cx21fs1, 40x, tokyo, japan) incorporated with a 20x canon camera. fig.1: microscopic photograph of the microalgae chlorella vulgaris used in the present study using microscope (cx21fs1, 40x) the suggested nutrient medium in this study was npk medium (20:20:20+te n:p:k) commercial fertilizer, which has the n as urea 2.1% and as ammonia 17.9%, p as phosphorus oxide 20%, k as potassium oxide 20% with trace element consist of mg 0.1%, zn 0.05%, mn 0.05%, fe 0.1%, cu 0.05%, b 0.02% and vitamin b 0.0005%. while the chu-10 consisted of 40 (mg/l) ca (no3)2, 25(mg/l) mgso4, 5(mg/l) k2hpo4, 20 (mg/l) na2co3, 25(mg/l) na2sio3, 8(mg/l) fecl3, both medium were prepared by dissolved these salts in ro water, while, the value of initial ph was adjusted to 6.23 using (0.1 n) of sodium hydroxide and hydrochloric acid. preparation of microalgae inoculum a stock solution of chlorella vulgaris was incubated in 500 ml conical flask in an environmental growth chamber at (25 ± 2 °c) http://www.iasj.net/ mahmood k. h. al-mashhadani and entisar mohsin khudhair -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 101 temperature and under continuous illumination by three cool-white fluorescent light tubes (10 watt and 10 inches length). agitation system was obtained by bubbling filtered atmospheric air in the bottom of the flask. the medium used in the cultivation of the microalgae was commercial available n: p: k 20:20:20+te fertilizer (provided from kule® inc.). advantages of this suggested nutrient are high water soluble and cheaper nutrients for biomass production. after seven days of inoculation, microalgae cells pre subculture by transferring it to fresh medium. figure 2 shows the starter culture of chlorella vulgaris microalgae in flasks at different times. fig. 2: photographic view of the batch cultivation for chlorella vulgaris with time experimental setup and measurements the experiments of cultivation chlorella vulgaris at different aeration periods were conducted in four conical flasks of 0.5 l capacity, operating in batch culture with a working volume of 350 ml. each flask enclosed by stopper with two pores one for aeration and other for air exhaust. air was supplied via air pump (hx-106a). the inlet air was dried by filtration through an in-line filter before entering the culture flasks to avoid contamination by condensation in the air tube airlines. this filter consists of cotton and activated charcoal that are arranged in layers. to minimize the contamination problems or infection that can be causes by potential pathogens and other microorganism, the flasks and nutrient media were sterilized. the procedure of sterilization was carried out corroding to ammar [17] using a water bath (julabo, model: eh (v.2), germany) with hot water at a temperature of (70-80 °c) for 20 minutes, as shown in figure 3. fig. 3: a sterilization of nutrients media by using water bath in each flask, 15 ml of culture was added and then completed to 350 ml working volume with fresh media solution for 14 days at room temperature (25 ± 2 °c) and under photoperiod artificial light (20 hr light/4 hr dark). agitation system was conducted by bubbling filtered air at bottom of the flask with different periods; 20hr, 6hr, 2hr and zero hour. all flasks were shaken manually thrice a day to meet their oxygen demands and keep the cell suspension for un-interrupted uniform multiplication of algal cell. samples of culture media were collected aseptically every 24hr intervals by taking a sample 5 ml of culture in 10 ml capacity vials to evaluate microalgae growth. the microalgae growth was determined by measuring the optical density (cell absorbance) with wavelength 680 nm [18, 19], using uv spectrophotometer http://www.iasj.net/ experimental study for commercial fertilizer npk (20:20:20+te n: p: k) in microalgae cultivation at different aeration periods 102 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net (genesys 10uv, usa) to ensure an exponential phase of growth and was maintained until it reached the stationary phase and correlated to the dry weight by a calibration curve. while the cell dry weight (biomass concentration, g l -1 ) was determined by using centrifuge (plc03, taiwan) at 3000 r/min for 20hr and drying by exposure to atmosphere for 24 hr, then at 60c 0 until constant weight. six culture samples were tested and calibration curve for relationship between optical density and cell dry weight was determined. for comparison study between n: p:k fertilizer and chu-10, two batch mode in 500ml conical flasks were used. value of ph was adjusted at 6.23 using (0.1 n) of sodium hydroxide and hydrochloric acid. ten mile of green chlorella vulgaris was added to each flask and completed to 450ml medium and were placed in environmental cultivation chamber. kinetic parameters the biomass concentrations (x, g l -1 ) that estimated via calibration curve were used to construct growth curve of biomass density versus time to determine the specific growth rates (μ, d -1 ), doubling time (td, d), maximum biomass concentration (xmax, g l -1 ) and volumetric biomass productivities (p, g l -1 d -1 ). the specific growth rate, µ (day -1 ) was estimated from equation 1 [20] … (1) where xt and x0 are the final and initial dry biomass concentrations (g l 1 ), respectively during the exponential logarithmic growth phase and δt is the cultivation time in day during the exponential logarithmic growth phase [21]. while, the doubling time (td, d) was calculated from equation 2 [9, 22]. … (2) biomass productivity, p (dry g l -1 day 1 ) in batch mode was calculated from the variation in biomass concentration within the cultivation time (day) according to equation 3 [23]. … (3) where xt is the dry biomass concentration (g l -1 ) at t (day) and x0 is the dry biomass concentrations at inoculation [9, 22]. result and discussion comparison study the growth of the microalgae cells was estimated by optical density (cell absorbance at 680 nm) every day. for counting, a 5 ml sample was aseptically removed from each culture using 10 ml capacity vials then correlated into dry weight by the liner regression y = 0.264 x. where’s y is the biomass concentration (g l -1 ) and x is the optical density (cell absorbance at 680 nm). cell dry weight (biomass conc.) was measuring by weighted the cells after filtering and dried it at 60 °c for one hour. then the growth curves of microalgae, specific growth rate (µ, d -1 ), doubling time (td, d) and biomass productivity (g l -1 d -1 ) were determined for each medium. figure 4 shows the characteristic of growth curves (lag, exponential, stationary and declining phases). it can be seen that the production of cell dry weight for the microalgae with npk medium was more than that produced if the chu-10 was used as a cultivation medium. in addition, with the n:p:k+te fertilizer medium, the rate http://www.iasj.net/ mahmood k. h. al-mashhadani and entisar mohsin khudhair -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 103 of growth reached the peak on the 11 th day, while in the chu.10 medium the rate of growth reached the peak on the 14 th day. the maximum biomass concentration reaches to 0.3249 g l -1 when cultivated in npk fertilizer, whereas reached to 0.212 g l -1 for cells cultivated in chu.10 medium. figure 5 shows the photographic view of the batch cultivation using npk and chu-10 medium. fig. 4: the growth curve of chlorella vulgaris cultivation in chu.10 and npk commercial fertilizer fig. 5: photographic view of the batch cultivation using n: p: k+te fertilizer media and chu-10 media maximum specific growth rate (µ, d -1 ) was also 0.375 d -1 and 0.249 d -1 for npk fertilizer and chu.10 medium respectively. biomass doubling time (td, d) was 1.8 day for npk fertilizer while 2.7 day for chu.10 medium as indicated in figure 6. while the productivity of chlorella vulgaris cells was 0.0328 g l -1 d -1 obtained in npk fertilizer and 0.019 g l -1 d -1 obtained in chu.10 medium. fig. 6: specific growth rate and doubling time for chlorella species in both medium from above results, it can be seen that npk fertilizer is preferred as cultivation media commercially and biologically. therefore; the current study used the npk medium in microalgae cultivation at different aeration periods. since, the results in this article agree with most of the literature concerning the use of commercial agricultural fertilizers, on the fact that the commercial fertilizer preparations can be as effective as analytical grade reagent for microalgae cultivation. it is well known, however, that the composition of culture media not only affects the cell productivity, but also affects yield of specific products and cell composition [24-26]. effect of aeration system on growth rate of microalgae the mathematical relationship between the optical density (with wavelength 680 nm) and the cell dry weight of chlorella vulgaris was determined by the linear regression, as shown in figure 7. … (4) where is the biomass concentration, which measured in (g l 1 ), and x is the optical density (od680 nm). the optical density was used to precisely predict the biomass concentration (r 2 ˃0.991; p <0.001). http://www.iasj.net/ experimental study for commercial fertilizer npk (20:20:20+te n: p: k) in microalgae cultivation at different aeration periods 104 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net therefore, the measured values of optical density were used to calculate the biomass of chlorella species in each experiment according the estimated equation in this study, to investigate the effect of aeration period by atmospheric air. fig. 7: calibration curve for relationship between optical density and cell dry weight in microalgae cultures, the growth curve has four growth phases. it starts with the lag or induction phase, which little increase in growth rate as cell density occurs. then the logarithmic phase in which the growth rate increases exponentially by depending on many factors such as algal species or type, medium temperature and light intensity. in addition, the stationery phase is the constant phase in which the cell density become relatively constant. and finally death phase in which occur declining in growth rate when the cell divisions decreases because some factors become influential to growth rate such factors as nutrients medium concentration, dissolved co2 and o2, ph, light and contamination risk. the present paper studied these phases through the growth curves as shown in figure 8. from this figure, it can be seen that the curves have a close biomass concentration during the first two day (lag phase). however, there is a significant increase in the rate of growth when increasing aeration time, as can be seen with 20 hr per day aeration compared with other periods aeration (i.e.6 and 2 hours). moreover the stationary phase at 9 th day comparable to other curves which have low growth and reach stationary phase at 11 th day ,11 th day and 8 th day when the culture aeration with 6 hr, 2hr and zero hr (control) per day respectively. as the cells grew up to plateau stage, the maximum biomass concentration (xmax, g l -1 ) observed 0.32 g l -1 for 20 hr aeration ,0.262 g l -1 for 6 hr aeration, 0.152 g l -1 for 2 hr aeration and 0.069 g l -1 for control but the last concentration obtained with longer time than the first one. fig. 8: effects of different aeration time on the growth of chlorella vulgaris from these results we note that it agrees with the requirements of algae growth it needs to be ventilated as a source of carbon dioxide with light, nutrients and water needed for photosynthesis and note that in case of increased ventilation increases the efficiency of the process of photosynthesis and so increasingly turning inorganic carbon to organic carbon help of sunlight in with metabolism cellular. the photosynthesis process in microalgae chloroplast can offer reasonable explanation about importance of http://www.iasj.net/ mahmood k. h. al-mashhadani and entisar mohsin khudhair -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 105 aeration system in such of current process, since the synthesis of glucose for microalgae carries out using carbon dioxide and water according to equation 5 → … (5) the gibbs free energy (∆g) of the above reaction is + 2823 kj mol -1 [27], thus this reaction is unspontaneous reaction thermodynamically. in fact the current process acts as chemical reaction which needs for enzymes as biocatalyst or external energy to occur. otherwise, it is difficult of occurrence of above reaction within thermodynamic concepts, since it is endogenic reaction. however, the scenario of this process can be changed when the kinetic energy is supplied by molecular through the conversion and storage the absorbed light into atp and nadph2 form as shown in figure 9 [28]. fig. 9: schematic mechanisms of photosynthesis in algae chloroplast the supplied energy has a sufficient ability to break existing bonds and formation new bonds. several enzyme catalyzed reactions may possibly progress in either the forward or opposite path way according to variation of light, temperature, concentration of reactant, and ph. therefore and to evaluate the directionality of the biological reaction, ∆g that consider as one of the most essential application in thermodynamic, can be used to do work in biochemistry reaction [29]. the previous studies have applied these principals by removal of the products to make spontaneous reaction and to produce more products such as production of biohydrogen and carbon dioxide from glucose via specific bacteria. park et al. [30] found that the overall h2 production increased here by 43% with chemical scavenging of the carbon dioxide concentration in the head space of the reactor due to reduction of partial pressure of h2 and co2. alshiyab et al. [31]; and tanisho et al. [32] demonstrated also that the removal of carbon dioxide by sparging the reactor with inert gas such as nitrogen leads to increase the h2 production. other researcher found similarity result such as mizuno et al. [33] investigate that sparging culture with n2 gas make h2 increased by 68%, and found that hydrogen yield 1.43 mole /mole glucose under n2sparging. kraemer and bagley [34] found the optimum n2 sparging at a rate 12ml (min. l-liquid) 1 maximised the yield of hydrogen at approximately (2 mole h2 / mole glucose), versus1mole h2/ mole glucose when no n2 sparging. liang et al.[35] also indicate increasing in h2 production at about 15% due to the reducing partial pressure of h2, when remove the dissolved gasses by using silicon rubber membrane. therefore, the directionality of a reaction is be estimated merely by the concentrations of the products and reactants that are existent, this applied for biochemical processes that happen at constant http://www.iasj.net/ experimental study for commercial fertilizer npk (20:20:20+te n: p: k) in microalgae cultivation at different aeration periods 106 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net temperature and pressure. the important spontaneous reaction in biological system is the hydrolysis of atp. the current results supported this principle; since decreasing the concentration of the product (e.g.o2) caused the reaction proceed to the forward direction as shown. hence the reaction comes to be more thermodynamically promising and move towards to the producing further products. the maximum specific growth rate (µmax, d -1 ) and biomass doubling time (td, d) at each different aeration time can be calculated and shown in figure 10 and figure 11 respectively. it is clear that the maximum value of growth rate (0.384 d -1 ) and shortest doubling time (1.8 day) where reported for the cells aerated at 20 hr per day. fig. 10: maximum specific growth rate for chlorella vulgaris at different sparging time fig. 11: doubling time for chlorella vulgaris at different sparging time a notable increase in maximum growth rate can be observed in these cultures with longer aeration time compared to that lowest aeration time, as shown from figure 10. the lowest maximum specific growth rate value (0.17 d -1 ) for culture no aeration (control), while the maximum specific growth rate increased to around (0.348 d -1 ) for culture aeration with 20hr. the maximum specific growth rate value for cultures aeration with 6hr and 2hr are (0.33 d -1 ) and (0.266 d -1 ) respectively. in addition, the shortest biomass doubling time (td, d) was 1.8 day at 20 hr aerated while the longest td was 4 days at control and at 6hr and 2hr aeration were 2.1 and 2.6 days respectively as notice in figure11. therefore, as maximum growth rate increased, biomass doubling time decreases, and cultivation becomes more economically sustainable. whereas microalgae can duplicate their biomass in less than 7 days, higher plants take many months or years [36]. in our study, the doubling time was equal to or less than 4 day. table 1 shows the main kinetic parameter (maximum specific growth rate µmax, biomass doubling time td, maximum biomass productivity pmax and maximum cell concentration x max) for culture chlorella species at different aeration time. table 1: kinetic parameters (µmax, td, pmax , xmax ) for chlorella vulgaris at different aeration time aeration time (hour) µmax (day -1 ) td (day) pmax (g l -1 . d 1 ) xmax (g l -1 ) 20hr 0.384 1.8 0.032 0.32 6hr 0.33 2.1 0.0234 0.262 2hr 0.266 2.6 0.0127 0.152 control 0.17 4 0.0058 0.069 the productivity of chlorella vulgaris (as a function of time) as http://www.iasj.net/ mahmood k. h. al-mashhadani and entisar mohsin khudhair -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 107 given in table 1, increases with aeration period increase. it can be seen that the best chlorella vulgaris obtained from the experiments that has a specific growth rate (µmax = 0.384 d 1 ), biomass doubling time (td = 1.8 day), maximum biomass productivity (pmax =0.0326 g l -1 d -1 ), and maximum cell concentration (xmax = 0.32 g l -1 ). all these results were obtained when the process was operated under 20 hr culture aeration. previous studies have reported similar values, for example blair et al. [37] and gonçalves [38].they obtained 0.369 d -1 and 393 d -1 as a maximum specific growth rate as well as 0.038 g l -1 d -1 and 0.07 g l -1 d -1 as a biomass productivity respectively, although, they have used carbon dioxide gas in the aeration system as a main source for carbon and as a regulator of the ph. from above it can be seen that the aeration system plays an important role in metabolic bioreactions via reduction the partial pressure of oxygen by removal of products gases (oxygen) to be more thermodynamically promising and move towards to the producing further products or as source of the carbon dioxide that found in air even with little percentage. conclusion the current article suggested utilization of npk fertilizer for bioprocess application (microalgae culture). in addition, different aeration periods were investigated in present study as well. the experimental data showed there is enhancement in growth rate of chlorella vulgaris in commercial fertilizer npk medium was more that with chu.10 medium. for example, with the rate of growth reached the peak on the 11 th day, while in the chu.10 medium the rate of growth reached the peak on the 14 th day. the maximum biomass concentration reaches also to 0.3249 g l -1 when cultivated in npk fertilizer, whereas reached to 0.212 g l -1 for cells cultivated in chu.10 medium. the present study proved that application of aeration system for the microalgae culture has a significant on growth rate, since the bioreactions become thermodynamically favorable and provide impetus for a higher level of production. moreover, this article demonstrated that the production of chlorella vulgaris increases when the sparging periods increase. acknowledgement the authors like to express sincere gratitude to prof. william university of sheffield, uk and dr. stephen j. wilkinson (chester university, uk) for their invaluable academic guidance. the authors are also grateful to ali muayad from baghdad university/ college of science / department of biology, for their scientific support for this research work. in addition, they also thankful to the department of chemical engineering in baghdad university. nomenclature x biomass concentration, (g l -1 ) xt biomass concentration at any time t, (g l -1 ) x0 biomass concentration at the inoculation, (g l -1 ) d time (day) od680 optical density at 680 nm wavelength td doubling time (day) δt cultivation time in day during the exponential growth phase xmax maximum biomass concentration, (g l -1 ) pmax maximum volumetric productivity, (g l -1 d -1 ) μ max maximum specific growth rate (day -1 ) http://www.iasj.net/ experimental study for commercial fertilizer npk (20:20:20+te n: p: k) in microalgae cultivation at different aeration periods 108 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net references 1. ramanathan, v., (1988), “the greenhouse theory of climate change: a test by an inadvertent global experiment”, journal of science, vol. 240, pp. 293–299. 2. song, c., (20060, “global challenges and strategies for control, conversion and utilization of co2 for sustainable development involving energy, catalysis, adsorption and chemical processing”, journal of catalysis today, vol. 115, pp. 2–32. 3. brown, l.m., and zeiler, k.g., (1993), “aquatic biomass and carbon dioxide trapping”, international journal of energy conversion and management, vol. 34, pp. 1005–1013. 4. chang, e. h., and yang, s. s., (2003), “some characteristics of microalgae isolated in taiwan for biofixation of carbon dioxide”, botanical bulletin academia sinica, vol.44, pp. 4552. 5. le treut, h., somerville, r., cubasch, u., ding, y., mauritzen, c., mokssit, a., peterson, t., and prather, m., (2007), “historical overview of climate change in: climate change 2007: the physical science basis”. contribution of working group i to the fourth assessment report of the intergovernmental panel on climate change, [solomon, s., qin, d., manning, m., chen, z., marquis, m., averyt, k. b., tignor, m., and miller, h. l., (eds.)], cambridge university press, cambridge, united kingdom. 6. hansen, j., sato, m., kharecha, p., beerling, d., berner, r., mansson, v., pagani, m., raymo, m., royer, d. l., and zachos, j. c., (2008), “target atmospheric co2 where should humanity aim”, open atmospheric science journal, vol. 2, pp. 217-231. 7. lin, c.c., liu, w.t., and tan, c.s., (2003), “removal of carbon dioxide by absorption in a rotating packed bed”, journal of industrial and engineering chemistry research, vol. 42, pp. 2381–2386. 8. ipcc (inter-governmental panel on climate change), (2001), “climate change 2001: mitigation”. cambridge university press, cambridge. 9. de morais, m.g. and costa, j.a.v., (2007). “biofixation of carbon dioxide by spirulina sp. and scenedesmus obliquus cultivated in a three stage serial tubular photo bioreactor”. journal of biotechnol, vol. 129, pp. 439–445. 10. sung, k.d., lee, j.s. , shin, c.s., park, s.c. and choi, m.j., (1999), “co2 fixation by chlorella sp. kr-1 and its cultural characteristics”, journal of bioresource technology, vol. 68, pp. 269273. 11. babcock, jr. r.w., malda, j., and radway, j.c., (2002), “hydrodynamics and mass transfer in a tubular airlift photobioreactor”, journal of applied phycology, vol. 14, pp. 169–184. 12. dote, y., (1994), “recovery of liquid fuel from hydrocarbon-rich microalgae by thermochemical liquefaction”, fuel, vol. 73, pp. 1855–1857. 13. miao, x.l., and wu, q.y., (2006), “biodiesel production from heterotrophic microalgal oil”, journal of bioresour technology, vol. 97, pp. 841–846. 14. minowa, t., (1995), “oil production from algal cells of dunaliella tertiolecta by direct thermochemical liquefaction”, fuel 74, 1735–1738. http://www.iasj.net/ mahmood k. h. al-mashhadani and entisar mohsin khudhair -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 109 15. sheehan, j., dunahay, t., benemann, j., and roessler, p., (1998), “a look back at the u.s. department of energy’s aquatic species program: biodiesel from algae”, national renewable energy laboratory, usa. 16. abed, i.j., al-hussieny, a.a., kamel, r.f., and jawad, a.m., (2014), “environmental and identification study of algae present in three drinking water plants located on tigris river in baghdad”. international journal of advanced research, vol. 2, pp.895-900. 17. ammar, s. h., (2016), “cultivation of microalgae chlorella vulgaris in airlift photo bioreactor for biomass production using commercial npk nutrients”. al-khwarizmi engineering journal, vol. 12, no.1, pp. 90-99. 18. mohd, y.a.y, hassan, j.m.b., ashikeen, n. m., sabuddin, r., muda, r. a., sulaiman, s., makpol, s. and wan, w.z.n., (2011), “fatty acids composition of microalgae chlorella vulgaris can be modulated by varying carbon dioxide concentration in outdoor culture”. african journal of biotechnology, vol. 10, no. 62, pp. 13536-13542. 19. jeong, m.l., gillise, j.m., and hwang, j.y., (2003), “carbon dioxide mitigation by microalgal photosynthesis”, bull. korean chem., vol. 24, no. 12. 20. chiu, s.y., kao, c.y., tsai, m.t., ong, s.c., chen, c.h., and lin, c.s., (2009), “lipid accumulation and co2 utilization of nannochloropsis oculta in response to co2 aeration”. journal of bioresour technology, vol. 100, pp. 833–838. 21. ketheesan, b. and nirmalakhandan, n., (2012), “feasibility of microalgal cultivation in a pilot-scale airlift driven raceway reactor”, journal of bioresource technology, vol. 108, pp. 196 202. 22. de morais, m.g. and costa, j.a.v., (2007). “carbon dioxide fixation by chlorella kessleri, chlorella vulgaris, scenedesmus obliquus and spirulina sp. cultivate in flasks and tubular photobioreactors”, biochemical lett. vol.29, pp. 1349-1352. 23. ryu, h.j., oh, k.k., and kim, y.s., (2009), “optimization of the influential factors for the improvement of co2 utilization efficiency and co2 mass transfer rate”, journal of industrial and engineering chemistry, vol. 15, pp. 471–475. 24. sánchez, s., martínez, m. e., and espinola, f., (2000), “biomass production and biochemical variability of the marine microalga isochrysis galbana in relation to culture medium”, biochemical engineering journal, vol. 6, pp. 1318. 25. lourenço, s.o., marquez, u. m. l., mancini, f. j., barbarino, e., and aidar, e., (1997), “changes in biochemical profile of tetraselmis gracilis i. comparision of two culture media”, aquacultural engineering journal, vol. 148, pp. 153-158. 26. imamoglu, e., sukan, e. f. v., and dalay, m. c., (2007), “effect of different culture media and light intensities on growth of haematococcus pluvialis”. international journal of engineering science, vol. 1, no. 3, pp. 5-9. 27. haynie, d.t., (2008), “biological thermodynamics”, cambridge university press, 2nd edition, p.137. 28. lodish h., berk a., zipursky s. l., matsudaira p., baltimore d., and darnell j., (2000), “molecular http://www.iasj.net/ experimental study for commercial fertilizer npk (20:20:20+te n: p: k) in microalgae cultivation at different aeration periods 110 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net cell biology”, 4th edition. w. h. freeman and company, new york. 29. gary r. k., (2004), “the concentration dependence of the δs term w in the gibbs free energy function: application to reversible reactions in biochemistry”, journal of chemical education, vol. 81, no.11, pp. 1599-1604. 30. park, w., hyun, s. h., oh, s. e., logan, b. e., and kim, i s., (2005), “removal of headspace co2 increases biological hydrogen production”, journal of environmental science and technology, vol. 39, pp. 4416–4420. 31. alshiyab, h., kalil, m. s., hamid, a. a., and yusoff, w. m. w., (2008), “removal of headspace co2 increases biological hydrogen production by c. acetobutylicu”, pakistan journal of biological sciences. vol.11, no.19, pp. 2336– 2340. 32. tanisho, s., kuromoto, m., and kadokura, n., (1998), “effect of co2 removal on hydrogen production by fermentation”, international journal of hydrogen energy, vol. 23 no.7, pp. 559–563. 33. mizuno, o., dinsdale, r., hawkes, f. r., hawkes, d. l., and noike, t., (2000), “enhancement of hydrogen production from glucose by nitrogen gas sparging”, journal of bioresour technology, vol. 73, pp. 59–65. 34. kraemer, j. t., and bagley, d. m., (2008), “optimization and design of nitrogen-sparged fermentative hydrogen production bioreactors”, international journal of hydrogen energy, vol. 33, pp. 6558–6565. 35. liang t., cheng, s., and wu, k., (2002), “behavioral study on hydrogen fermentation reactor installed with silicone rubber membrane”, international journal of hydrogen energy, vol.27, pp. 1157–1165. 36. vonshak, a., abeliovich, a., boussiba, a., arad, s, and richmond, a., (1982), “production of spirulina biomass: effects of environmental factors and population density”, biomass journal, vol. 2, pp.175–85. 37. blair, m. f., kokabian, b., and gude, v. g., (2013), “light and growth medium effect on chlorella vulgaris biomass production “, journal of environmental chemical engineering, pp.1-10. 38. gonçalves, a. l., (2012), “environmental benefits of chlorella vulgaris and pseudokirchneriella subcapitata co2 capture and bioenergy production”, msc thesis, do porto university. http://www.iasj.net/ http://www.whfreeman.com/ http://www.whfreeman.com/ http://scialert.net/jindex.php?issn=1028-8880 http://scialert.net/jindex.php?issn=1028-8880 1 ijcpe vol.11 no.1 (march 2010) iraqi journal of chemical and petroleum engineering vol.11 no.1 (march 2010) 1-9 issn: 1997-4884 separation of bovine serum albumin using chromatographical column: parameters and simulation cecilia khoshaba haweel * , ahmed j. ali and samar n. alias * chemical engineering department college of engineering university of baghdad – iraq abstract a liquid-solid chromatography of bovine serum albumin (bsa) on (diethylaminoethyl-cellulose) deae-cellulose adsorbent is worked experimentally, to study the effect of changing the influent concentration of (0.125, 0.25, 0.5, and 1 mg/ml) at constant volumetric flow rate q=1ml/min. and the effect of changing the volumetric flow rate (1, 3, 5, and 10 ml/min) at constant influent concentration of co=0.125mg/ml. by using a glass column of (1.5cm) i.d and (50cm) length, packed with adsorbent of deae-cellulose of height (7cm). the influent is introduced in to the column using peristaltic pump and the effluent concentration is investigated using uv-spectrophotometer at 30oc and 280nm wavelength. a spread (steeper) break-through curve is gained at lean feed concentration of 0.125mg/ml, while the flow rate greater than (3ml/min) is almost the same. so it is butter to work at low volumetric flow rate between (1-3) ml/min. the equilibrium-dispersion model of liquid-solid chromatography for a binary mixture, related with langmuir isotherm correlation is used in the modeling of this work. the resulting model is solved numerically by using matlab v.6.5 program. introduction chromatography is a very special separation process for a multitude of reasons! first of all, it can separate complex mixtures with great precision. even very similar components, such as proteins that may only vary by a single amino acid. second, chromatography can be used to separate delicate products since the conditions under which it is performed are not typically serving (hubble, 2004). a mixture of various components enters a chromatography process and is allowed to come into contact with two phases, the stationary phase is contained in a column where the mobile phase moves in a controlled manner relative to the stationary phase, carrying with it any material that may prefer to mix with it. to determine the differences in the concentration of mobile phase (solute), a detector is used which can give a curve of the separated substance. so, the name chromatography stems from this, where each separated substance has different color on the stationary phase and gives different curve from the detector (stock, 1974, encyclopedia, 1992 and hubble, 2004). frontal chromatography analysis has widely used for large scale separations of industry. it is made in which conditions are chosen that the desired component very quickly saturates the column and emerges from the column shortly after the feed is saturated. impurities, on the other hand, are strongly retained by the adsorbent and feeding is continued until the front of the adsorbed impurities approaches the column outlet (simpson, 2001). ion-exchange technique of chromatography is used to represent the frontal analysis. that was because of the simplicity of this technique where separation take place according to charge of both solid adsorbent and the separated molecules. there can be two types of functional groups of exchangers, covalently attached to the support beads. these are called anion exchangers (resin with positive functional groups) or cation university of baghdad college of engineering iraqi journal of chemical and petroleum engineering separation of bovine serum albumin using chromatographical column: parameters and simulation 2 ijcpe vol.11 no.1 (march 2010) exchangers (resin with negative functional groups) (raply and walker, 1998, and freifelder, 1998). representing the frontal analysis with ion-exchange chromatography by a mathematical model is an important feature not only for experimental data but, also for the process design and optimization. experiments need to be carried out to get the mass-transfer parameters for modeling and simulation and comparisons with experimental results indicated that the prediction was acceptable. experimental work a system of bovine serum albumin (bsa) protein adsorbed onto deae-cellulose was chosen to study the frontal analysis and compare it with the theoretical work (alias, 2007). bovine serum albumin protein of 66430 molecular weight from sigma chemical company dissolved in (5mg/ml) tris-hcl buffer of 98% purity mead by bbh company to produce the mobile phase of the chromatography system at (ph 7). deae-cellulose anion-exchanger from sigma chemical company was used as stationary phase of the chromatography system. five samples of different weights of deae-cellulose was prepared to evaluate the equilibrium isotherm, each one of them is put in a beaker with (30ml) of bsa solution of concentration (0.12mg/ml) and ph of 7. the samples were shaked at (30oc) for about (26 hours) then the concentrations were calculated using uvspectrophotometer. the amount of solute adsorbed into deae-cellulose q in (mg/g deae-cellulose) was found according to the equilibrium relation: a lo w vcc q )(   (1) the adsorption isotherm was obtained by plotting q vs. c a glass beaker of (250ml) capacity was prepared for batch experiment. a (50ml) of bsa-solution was added to the beaker containing (3.37mg) of deae-cellulose. at zero time, deae-cellulose of certain weight was added. samples were taken every 10 minutes during the experiment and concentration is measured using uvspectrophotometer. frontal chromatography experiments were carried out to find the breakthrough curve of bsa adsorbed to deaecellulose bed. to study the effect of changing the initial concentration (0.125, 0.25, 0.5, and 1 mg/ml) at constant volumetric flow rate of (1ml/min) and changing the volumetric flow rate (1, 3, 5, and 10 ml/min) at constant initial concentration of (0.125mg/ml). the procedures of all run experiments are as follows: deae-cellulose was poured into the column at (7cm) length. bsa-solution was prepared at the desired concentration for each run using tris-hcl buffer. the solution was introduced to the top of the column using peristaltic pump at a certain flow rate. samples were collected directly from the bottom of the column using tubes for every (1ml) and then the concentration was measured using uv-spectrophotometer at 280 nm wavelength as in (fig. 1). the resulting breakthrough curves were determined by plotting effluent concentration (c/co) against dimensionless time τ. (alias, 2007). fig.1 the experimental apparatus of bsa adsorbed in deae-cellulose bed. modeling and simulation batch adsorber batch adsorber analyses are important to calculate the external mass transfer coefficient kf (m/s) of batch experiment and pore diffusivity dp (m 2 /s). the formulation of batch adsorber based on (ahmed, 2006). for batch adsorber, the mathematical model with pore diffusion model is:  mass balance in fluid-bulk phase: 0)( 3 pr   prbif pp ai l cck r w dt dc v  (2) where: vl = volume of fluid in the batch adsorber wa = mass of adsorbent cecilia khoshaba haweel and ahmed j. ali and samar n. alias ijcpe vol.11 no.1 (march 2010) 3  mass balance inside particle phase: )( 1 2 2 r c r rr d dt dq t c p ppp p p         (3)  initial conditions and boundary conditions ][ 00:0 00:0 , 00 p p rrp bf rr p ppp rr p pob cck r c drr dr dq r c r qccct                                     in case of using langmuir isotherm correlation: bc bc qq p p m   1 (4) where cb and cp are the solute concentration in the fluidbulk and particle phase, respectively. the external mass transfer coefficient for the solute adsorbed at certain particle size and optimum agitation speed, can be obtained by the analytical solution for equation (2.29) where at t = 0, cp,r=rp = 0 and cb = co, hence:          o t a lpp f c c tw vr k ln 3  (5) where co, ct are the solute concentration at time zero and time (t) and obtained from the typical concentration decay curve. modeling of liquid-solid chromatographical column the formulation of chromatographical column is based on (volker, 1999, and eggers, 2003), the governing equations can be obtained from differential mass balances of the bulk-fluid phase and the particle phase, respectively, for component i.  continuity equation in the bulk-fluid phase: using cpi, the concentration in the stagnant fluid-phase (in the macropores), and writing the expression of interfacial flux leads to:   prrpibi p fii cc r k t q    , 3 (7)    013 ,2 2              prrpibi pb bfibibibi bi cc r k t c z c z c d    (8)  continuity equation inside the macropores: the particle phase continuity equation in spherical coordinates is:  initial and boundary conditions the initial and boundary conditions may be represented by the following equations: initial condition (t = 0): 0),0(  zcc bibi (10) 0),,0(  zrcc pipi (11) separation of bovine serum albumin using chromatographical column: parameters and simulation 4 ijcpe vol.11 no.1 (march 2010) boundary conditions: z = 0:  oibi bi bi cc dz c     (12) z =l: 0   z cbi (13) r = 0: 0   r c pi (14) r = rp:   prrpibi pip fipi cc d k r c    ,  (15) model parameters of fixed-bed chromatography column a) correlations to estimate (molecular diffusivity) dm: polson proposed the equation for high molecular weight solutes: ) . (104.9 3/1 15 w m m t d    (16) where: t is temperature (k), µ is the viscosity of the solution (pa·s) and mw is the molecular weight of the solute (polson, 1950). b) correlation to estimate mass transfer coefficient kf in fixed-bed adsorption: )100(rere45.10.2 5.03/1  scsh (17) where: sh=2rpkf/dm (sherwood number), sc = µ/(ρdm) (schmidt number), and re=2rpρν/µ (reynolds number). µ is the fluid (water) viscosity, and ρ is the fluid (water) density (jian, 2004, and montesinos, 2005). c) correlation to estimate db the axial dispersion coefficient can be estimated from the following correlation: )10(re re011.00.2 2 48.0    p b r d (18) where: ν is the interstitial velocity along the column = 4q/επd 2 (q is the volumetric flow rate) and re=2rpρν/µ (jian, 2004, and montesinos, 2005). simulation program the model equations must be solved numerically. the numerical method of lines (mol) is used in order to solve the coupled system of pde obtained ether from batch adsorber or chromatography column. the bulkfluid phase and the particle equations are first discretized using the fe (finite element) and the oc (orthogonal collocation) methods, respectively. the resulting ode system is solved using an existing ode solver provided by matlab v-6.5.the code of matlab m-files for both batch adsorber and chromatography column are presented in (ahmed, 2006). this program is used for both single and multicomponent systems after changing some parameters. the model parameters used in the simulation program are listed in tables 1 and 2. results and discussion isotherm determinations and constants the adsorption isotherm of bsa adsorbed onto deaecellulose of 0.35mm-particle size at (30 o c and 5mg/ml tris-hcl buffer ph 7) is shown in (fig. 2), were the initial concentration of bsa-solution was (0.12 mg/ml). by fitting the equilibrium data with langmuir isotherm correlation, the results were good (qm = 2.022 mg/g) and (b = 13.083 ml/mg). fig. 2: adsorption isotherm of bsa onto deaecellulose at (30 o c) intraparticle diffusivity coefficient dp estimations in order to find intraparticle diffusivity coefficient dp, it was needed to find the mass transfer coefficient kf in batch adsorption process and then the numerical solution of batch adsorber model is applied. the external mass transfer kf, coefficient in batch adsorber was computed from initial rate data, (i.e. from the concentration decay curve fig. 3) using equation (5):          o t a lpp f c c tw vr k ln 3  (19) cecilia khoshaba haweel and ahmed j. ali and samar n. alias ijcpe vol.11 no.1 (march 2010) 5 where co, ct are the solute concentration at time zero and time t. for accurate estimation of kf, samples were taken after 10, 20, and 30 minutes and analyzed immediately. the average calculated value of kf was 1.0683×10 -6 m/s. the pore diffusivity coefficient was derived from the typical concentration decay curve by iterative search technique predicted on the minimization of the difference between experimental and predicted data from pore diffusion model (ahmed, 2006). the results are shown in (fig. 3). the pore diffusivity coefficient for bsa solute according to (fig 3) is 0.078×10 -10 m 2 /s. fig. 3 comparison of the measured concentration-time data at (30 o c) with that predicted by pore diffusion model in batch adsorber. chromatography experiments  figures (4 to 7) were obtained from the adsorption of bsa solution on deae-cellulose adsorbent at different concentrations of influent co that at q = 1ml/min. as follows: fig. 4 break-through curve of bsa on deae-cellulose at co = 0.125mg/ml fig. 5 break-through curve of bsa on deae-cellulose at co = 0.25mg/ml fig. 6 break-through curve of bsa on deae-cellulose at co = 0.5mg/ml figure 8 represents the effect of changing the initial concentration at (0.125, 0.25, 0.5, and 1 mg/ml). from this figure, the change in inlet solute concentration markedly affects the shape and position of the breakthrough curve. the higher the solute concentration the faster the break-through. however, the quantity of solution to be supplied is large when the solute concentration is low to arrive the optimum value. fig. 7 break-through curve of bsa on deae-cellulose at co = 1mg/ml separation of bovine serum albumin using chromatographical column: parameters and simulation 6 ijcpe vol.11 no.1 (march 2010) fig. 8 break-through curve of bsa on deae-cellulose at different initial concentrations  figures (9 to 12) were obtained from the adsorption of bsa solution on deae-cellulose adsorbent at different volumetric flow rates q that at co = 0.125mg/ml initial concentration. as follows: fig. 9 break-through curve of bsa on deae-cellulose at q = 1ml/min fig. 10 break-through curve of bsa on deae-cellulose at q = 3ml/min fig. 11 break-through curve of bsa on deae-cellulose at q = 5ml/min fig. 12 break-through curve of bsa on deae-cellulose at q = 10ml/min figure 13 represents the effect of changing the volumetric flow rate of the mobile phase for (1, 3, 5, and 10 ml/min). flow rate affects the film mass transfer coefficient. if rp is unchanged, for correlation 17, kf is proportional to ν 0.5 . the flow rate also affects the axial dispersion coefficient according to correlation 18. for higher flow rates, break-through is faster and poor adsorption efficiencies will result. when the flow rate is low, an increase in the spreading of the break-through curve will occur and an increase in the time that the solute is in contact with the stationary phase, allowing more time for adsorption and permitting near-local equilibrium conditions. that the break point is unchanged which is about 0.6 of initial concentration. cecilia khoshaba haweel and ahmed j. ali and samar n. alias ijcpe vol.11 no.1 (march 2010) 7 fig. 13 break-through curve of bsa on deae-cellulose at different volumetric flow rates  all the resulting break-through curves obtained to the adsorption of bsa on deae-cellulose bed, are almost sharp and the break point occur about 0.557 from the initial concentration for high volumetric flow rates, and the adsorption process is faster at about (3040) minutes. from the observations of fig. 13, the break-through curves obtained for volumetric flow rates of (3-10 ml/min) are almost the same (i.e. the break-through curves are almost compatible).  table 1 batch adsorber of bsa on deaecellulose system at 30 o c. simulation data parameter value rp 0.3510 -3 m εp 0.6 b 13.083 m 3 /kg qm 0.002022 kg/kg dp 0.07810 -10 m 2 /s kf 1.068310 -6 m/s ρp 309.5 kg/m 3 vl 0.0510 -3 m 3 wa 3.3710 -3 kg co 0.12 kg/m 3 table 2 data used in the simulation program of chromatography column parameter value column length l 0.07 m column diameter d 0.015 m particle diameter rp 0.3510 -3 m column porosity ε 0.775 particle porosity εp 0.6 axial dispersion db correlation (18) pore diffusivity dp 0.07810 -10 m 2 /s molecular diffusivity dm correlation (16) external mass transfer coefficient kf correlation (17) maximum adsorption capacity qm 0.002022 kg/kg langmuir isotherm constant b 13.083 m 3 /kg bed density ρp 309.5 kg/m 3 conclusions 1. comparisons were made between the results obtained from the model program and that gained from experimental work data, the agreement was very good, because all the parameters used in the model program were evaluated ether experimentally or by empirical relations of grate accuracy. this program is applied in all cases of liquid-solid chromatography systems with a very good accuracy. 2. for the experimental work data or literature data, langmuir isotherm correlation gives good results. this correlation is a good assumption for the system of very low concentrations of influent. 3. from the experimental worked data it was concluded that it is preferable to work with lean feed and low volumetric flow rate. in those conditions, a steeper or spread break-through curve will be gained which lead to increase the solute recovery efficiency. also the effect of increasing the volumetric flow rat more than (3ml/min) is not efficient. 4. whenever the break-through curve is spread (steeper), the break-through time point will occur with less c/co ratio 5. axial dispersion coefficient db, which is affected by the flow rate of the system is more significant at lower flow rate and is less noticeable as the rate is increased, but the pore diffusivity dp and external mass transfer coefficient kf is not that influential parameter because it represent the diffusivity inside the pore of particle, which its size is very small. separation of bovine serum albumin using chromatographical column: parameters and simulation 8 ijcpe vol.11 no.1 (march 2010) nomenclature notation ai constant from langmuir correlation (qm . b) bi langmuir isotherm constant (m 3 /kg) bii biot number of mass transfer for component i, (kfrp/εpdpi). ( ) coi concentration used for nondimensionalization, max{cfi(t)}. ct concentration of solute at any time. (kg/m 3 ) cbi bulk-fluid phase concentration of component i, (kg/m 3 ) cfi feed concentration profile of component i a time dependant variable (kg/m 3 ) cpi concentration of component i in the stagnant fluid phase inside theparticle macropores (kg/m 3 ) c*pi concentration of component i in the solid phase of particle (kg/m 3 ) cbi = cbi /coi ( ) cpi = cpi/coi ( ) c*pi = c*pi / coi ( ) dbi axial dispersion coefficient of component i (m 2 /s) dpi pore diffusivity coefficient of component i (m 2 /s) dm molecular diffusivity (m 2 /s) d inner diameter of a column (m) kfi, external mass transfer coefficient of component i (m/s) l column length (m) mw molecular weight. peli peclet number of axial dispersion for component i, νl/dbi. q volumetric flow rate of mobile phase (m 3 /s) q concentration of solute in stationary phase bed (kg solute/kg sorbent) qm maximum adsorption capacity (kg solute/kg sorbent) r radial coordinates for particle re reynolds number for sphere, (2rpρν/μ). rp particle radios (m) r = r/rp sc schmidt number, (μ/ρdm). sh sherwood number for sphere, (2rpkf/dm). t time (s) t temperature (c) vl the final volume of the sample put in beaker (ml) z dimensionless axial coordinate z/l. greek εb column or bed porosity. εp particle porosity. ν interstitial velocity, (4q/εbπd 2 ). τ dimensionless time. μ fluid (water) viscosity (pa.s). ρ fluid (water) density (kg/m 3 ). ρp particle density (kg/m 3 ). subscripts and superscript p particle phase. m mono layer. i i-th component. j j-th component. * particle phase concentration abbreviations bsa bovine serum albumin. fdm finite difference method. fem finite element method. ocm orthogonal collocation method. ode ordinary differential equation. pde partial differential equation. references 1. alias s. n., 2007, "separation of biological materials using chromatographical column", m sc thesis submitted to baghdad university. 2. ahmed kawther w., 2006,”experimental and modeling for the removal of multi pollutants by adsorption”. a phd thesis submitted to baghdad university. 3. eggers r., 2003, “simulation of frontal adsorption”. report submitted to the technische universitat hamburg-harburg (tuhh). 4. “encyclopedia of chemical technology”, 1992. forth edition, volume 6, a wily-interscience publication. 5. freifelder david, 1998, “physical biochemistry”, second edition, w. h. freeman and company, new york. 6. jian-gang l. u., feb. 28, 2004, “mathematical modeling of salt-gradient ion-exchange simulated moving bed chromatography for protein separations”. journal of zhejiang university science (jzus). http://www.zju.edu.cn/jzus e-mail: jzus@zju.edu.cn 7. hubble john, 2004, “adsorption and chromatographic separations”. literature (lecture) http://people.bath.ac.uk/cesjh/adsorb.htm email: mailto:cesjh@bath.ac.uk http://www.zju.edu.cn/jzus mailto:jzus@zju.edu.cn http://people.bath.ac.uk/cesjh/adsorb.htm mailto:cesjh@bath.ac.uk cecilia khoshaba haweel and ahmed j. ali and samar n. alias ijcpe vol.11 no.1 (march 2010) 9 8. montesinos-cisneros r. m., guzmلn-zamudio r. ortega-lpَez j., tejeda-mansir y. a., marzo 2005, “frontal chromatography of plasmids: parameters estimation and simulation”. revista mexicana de ingenieria quimica vol. 4 (2005) 47-58 9. rapley ralph and walker john m., 1998, “molecular biomethods handbook”. humana press, totowa, nj.s 10. simpson john m., 2001, “protein purification process engineering, marcel dekker, inc. 11. stock r. and rice c. b. f., 1974, “chromatographic methods”, halsted press new york. 12. volker kasche, 1999, “simulation of liquid chromatography and simulated moving bed (smb) systems”. a phd thesis submitted to hamburg university. 13. polson, a. (1950). “some aspects of diffusion in solution and a definition of a colloidal particle”. j. phys. colloid chem., 54, 649-652. المعامالت والمحاكات: فصل مصل الذم الحيواني باستخذام عمود الكروماتوكراف طيظيهيا خٕشاتا ْأيم 1 حًذ خٕاد ػهيو, 2 طًزَداذ انياصٔ خايؼح , كهيح انُٓذطح. 3لظى ُْذطح انكيًياء انحياذيح , خايؼح تغذاد, كهيح انُٓذطح. 2لظى انُٓذطح انكيًيأيح , خايؼح تغذاد, كهيح انُٓذطح. 1 لظى ُْذطح انكيًياء انحياذيح, تغذاد الخالصة -diethyleaminoethiel) ػهٗ يادج (bovine serum albumin)انظائم نًصم انذو انحيٕاَي -كزٔياذٕكزاف انصهة cellulose)ٔا (deae-cellulose)0.5 ,0.25 ,0.125)نذراطح ذأثيز انرغيز انثرزكيش انذاخم انٗ انؼًٕد . لذ ذى اشرغانّ ػًهيا, and 1mg/ml) تثثٕخ يؼذل اندزياٌ انحدًي (1ml/min) 5 ,3 ,1) ثى دراطح ذأثيز انرغيز تًؼذل اندزياٌ انحدًي, and 10ml/min) ترثٕخ انرزكيش انذاخم (0.125mg/ml) . انؼًم انردزيثي لذ ذى تاطرخذاو ػًٕد سخاخي َصف عٕل لغزِ انذاخهي انظائم . ( طى7) تغٕل deae-cellulose (diethylaminoethyl-cellulose), يحشٕ تًادج ( طى50)ٔعٕنّ (طى1.5) , ٔذزكيش انظائم انخارج ذى لياطّ تاطرخذاو خٓاس األشؼح peristaltic pump انذاخم يذخم إنٗ انؼًٕد تاطرخذاو يضخح يٍ َٕع 30) تذرخح حزارج uv-spectrophotometer فٕق انثُفظديح o c) تغٕل يٕخي (280 nm) . كاٌ ذزكيش انظائم انذاخم (0.125mg/ml) األفضم الَّ يؼغيbreak-through point لهيهح يغ break-through curveْذا انرزكيش . يُثظظ (0.125mg/ml) ُْا, يؼذالخ اندزياٌ انحدًي انري ْي الم يٍ . اطرخذو في ذغثيك ذدارب أخزٖ نًؼذالخ خزياٌ يخرهفح (3ml/min) نٓذا يٍ األفضم نٓذا انُظاو أٌ يؼًم ػهٗ يؼذل خزياٌ حدًي لهيم . ذكٌٕ ذمزيثا يرغاتمح نُفض انظزٔف انرشغيهيح انصهة نخهيظ ثُائي انًزتٕط _يٕديالخ انرٕاسٌ انًرشرد نهكزٔياذٕغزاف انظائم. تُفض انظزٔف (3ml/min-1)يرزأذ تيٍ انًٕديم انُاذح لذ حم ػذديًا تاطرخذاو تزَايح . تؼاللح الَكًٕر ايشٔثيزو لذ اطرخذو في اشرماق انًٕديم انزياضي نٓذا انؼًم matlab v.6.5 . iraqi journal of chemical and petroleum engineering vol.16 no.3 (september 2015) 2333 issn: 1997-4884 enhancement of uniformity of solid particles in spouted bed using stochastic optimization ghanim.m. alwan chemical engineering dept., university of technology, baghdad, iraq abstract performance of gas-solid spouted bed benefit from solids uniformity structure (ui).therefore, the focus of this work is to maximize ui across the bed based on process variables. hence, ui is to be considered as the objective of the optimization process .three selected process variables are affecting the objective function. these decision variables are: gas velocity, particle density and particle diameter. steadystate solids concentration measurements were carried out in a narrow 3-inch cylindrical spouted bed made of plexiglas that used 60° conical shape base. radial concentration of particles (glass and steel beads) at various bed heights and different flow patterns were measured using sophisticated optical probes. stochastic genetic algorithm (ga) has been found better than deterministic search for study mutation of process variables of the non-linear bed. spouted bed behaved as hybrid system. global ga could provide confirmed data and selected best operating conditions. optimization technique would guide the experimental work and reduce the risk and cost of operation. optimum results could improve operating of the bed at highperformance and stable conditions. maximum uniformity has been found at highdensity, small size of solid beads and low gas velocity. density of solids has been effective variable on ui.velocity of gas and diameter of solid particles has been observed more sensitive decision variables with ui mutations. uniformity of solid particles would enhance hydrodynamic parameters, heat and mass transfer in the bed because of improving of hold-up and voids distributions of solids. the results of the optimization have been compared with the experimental data using sophisticated optical probe and computed tomography technique. key words: genetic algorithm; spouted bed; solids; stochastic optimization; uniformity. introduction gas-solid spouted beds are either cylindrical bed with cone base or the whole bed is in a cone shape where the gas enters as a jet. the gas forms a spout region that carries the solids upward in a diluted phase that forms a fountain at the top of the bed where the solids fall down and move downward in the annular region. among several configurations typical of gas-solids fluidization, spouted beds have demonstrated to be characterized by a number of advantages, namely a reduced pressure drop, a relatively lower gas flow rate, the possibility of handling particles coarser than the ones treated by bubbling fluidized beds. iraqi journal of chemical and petroleum engineering university of baghdad college of engineering enhancement of uniformity of solid particles in spouted bed using stochastic optimization 24 ijcpe vol.16 no.3 (sept. 2015) -available online at: www.iasj.net additionally, significant segregation is prevented by the peculiar hydraulic structure. spouted bed can be realized by replacing the perforated plate distributor typical of a standard fluidized bed with a sample orifice, whose profile helps the solids circulation and voids stagnant zones. when the gas flow rate is large enough, the spout reaches the bed surface and forms a "fountain" of particles in the free board (fig.1). after falling on the bed surface, the solids continue their downward travel in the "annulus" surrounding the spout and reach different depths before being recaptured into the spout [1] and [2]. a spouted bed is a special case of fluidization. it is an effective means of contacting gas with coarse solid particles. there is increasing a application of spouted such as; coating, desulfurization, co2 capture, combustion and gasification of coal and biomass [3].the spouted bed is a kind of high performance reactor for fluid-solid particles reaction, also it is a hybrid fluid-solid contacting system [4]. it is better to develop the design of the spouted bed to enhance uniformity of the products resulting from the chemical or physical treatment due to the elimination of the back mixing .uniformity of solid particles enhances the mass and heat transfer in addition improves the conversion of the reactants in the spouted bed [5]. many non-linear mathematical equations of chemical processes are either not differentiable or need a lot of difficult mathematical treatment for differentiating. therefore, stochastic sampling methods have been found better than deterministic algorithms for optimize such functions. genetic algorithm (ga) search from a population of points, not a single point. hence gas are said to be suitable global optimization techniques for hybrid non-linear systems. motivation and objective the present work is a part of scaleup methodology in the multiphase and multi-scale processes laboratory (mmpl) of chemical and biological engineering department, missouri university of science and technology, usa.uniformity index of solids (ui) could improve performance of the spouted bed. enhancement of ui is depending on process variables. the present work focuses on study of effect of the selected decision variables (gas velocity, solid's density and solid's diameter) on ui across the bed. steady-state measurements are carried out at different operating conditions. the objective is to maximize ui. stochastic ga is global search for non-linear hybrid bed .optimal results will guide the decision makers to select the best operating conditions. this will reduce the risk of experimental runs and cost for operating and design. optimum results will be confirmed by using sophistical optical probes and computed tomography technique (ct). material and methods 1experimental set-u the experimental set-up was designed and constructed in the best way to collect the data as explained in figs.(1and2) .the cylindrical spouted bed is made of plexiglas. the bed is (3 inches in diameter and 36 inches in height) on which 20 holes (0.5 inch in diameter) are perforated-vertically. at the bottom of the bed, there is a 60° cone-shaped base with height of 3inch.the plexiglas spouting nozzle has diameter of 0.25-inch locates in the center of the conical base. the spouted gas is air supplied from the air compressor and the airflow rate is controlled by pressure regulator and measured by flow-meter (fig. 1). the ghanim.m. alwan -available online at: www.iasj.net ijcpe vol.16 no.3 (sept. 2015) 25 solid particles used are steel and glass beads have good reflective properties (not black) with different sizes and properties as shown in table(1).holes are drilled at vertical intervals of (1.86 inch) along the column wall in which the optical probes are placed at different radiant locations: 1.5, 1.25, 1.0, 0.75, 0.5, and 0.25-inch. the spouted bed was divided to three positions: position 1 with head of 7.5inch, while positions 2 and 3 have heads of 5.5 and 3.5 inches respectively above the conical-base. fig.1, diagram of experimental setup fig.2, photograph of spouted bed system the newly optical probe (0.5x0.5mm) as shown in figs. (3 and 4) was used to measure both solids concentration and solids velocity and their fluctuation. the concentrations of solid particles were measured in the radial and axis directions by the pv6 particle analyzer (fig.5).pv6 was manufactured by the 'institute of chemical metallurgy, chinese, academy of science’. it consists of; photoelectric converter and amplifying circuits, signal pre-processing circuits, high-speed a/d interface card and its software pv6, is adapted to the optical probes. three decision variables were selected, which are affecting on ui of solid particles. these decision variables are; air velocity, particle's density and particle's diameter. table 1, properties of beads material dp (mm) s (kg/m 3 ) € ø steel beads 1.09 7400.0 0.42 1.0 glass beads 1.09 2450.0 0.42 1.0 glass beads 2.18 2400.0 0.41 1.0 fig.3, structure of optical probe enhancement of uniformity of solid particles in spouted bed using stochastic optimization 26 ijcpe vol.16 no.3 (sept. 2015) -available online at: www.iasj.net fig.4, photograph of optical probe fig.5, on-line pv6 system 2experimental procedures measuring of particles concentration the probe is inserted into the measuring port on the bed. the probe should be installed such that the direction mark on the middle part of the probe is in conformity with or opposite to the flow direction of material .the optical probe is calibrated for measuring the local particles concentration. for empty-bed state, the solids concentration is equal to zero correspond to zero voltage of probe signal. under the bulk concentration state (material concentration is equal to 1.0), the output signal from the probe is equal to 4.5 voltages. two or three bundles of optical fibers with diameter of 0.5 mm are arranged at certain interval according to different sizes of particles to be measured by the optical probe. the light source is introduced into the measuring area in front of the optical fibers (fig.3). the reflecting lights of particles at the end face of the optical fibers are transmitted into the photoelectric detector in the instrument through the same bundle of optical fibers, and are converted to voltage signals corresponding to the concentration of particles as shown in fig.(5). to choose the appropriate probe, the average particle diameter should not exceed the diameter of the optical fiber in the probe. the probe tips measure the number of particles in a measuring volume in front of them. in the actual experiments, the optical probes measure voltage and solids concentration is then obtained through the following calibration equation: ci= [(vi-vmin)/ (vmax-vmin)]... (1) where: ci: local relative concentration of solid particles, [-] vi: voltage for particular run, [-] vmin: minimum voltage for the particular run, [-] vmax: maximum voltage for the particular run, [-] measuring of uniformity index uniformity index (ui) is a measure of the homogeneity of solid particles across the bed. in this work, ui was evaluated by eq. (2), which was developed by [6],[7] and [8]. for steady state, and at different operating conditions, concentration of solids was measured for each location in radiant-direction and axial-direction of the bed. from collected data,ui ghanim.m. alwan -available online at: www.iasj.net ijcpe vol.16 no.3 (sept. 2015) 27 would be calculated for each position by the following equation: ui= (cav-cmin)/ (cmax-cmin)… (2) where; cav: average solid concentration,[-] cmin: minimum solid concentration[-] cmax: maximum solid concentration [-] ui: uniformity index of the solid particles, [-] the values of ui were confirmed by optical probe signals and computed tomography technique (ct) as shown in fig.(6).ct is radioactive technique based on gamma ray. the red color indicates to high concentration of solids (solid bulk), while the blue color indicates to very low concentration of particles (gas bulk). the calibration of the optical probe needed to about (30-40 minutes).the interval time of each measurement was within 3.0 minutes. the starting time of the experimental rig was 30.0 minutes. however, each experiment needed to about two hours and for reliability, each experiment was repeated twice. fig.6, image of solids distribution at radiant direction by using ct 3formulating of optimization problem the available experimental data have been used to correlate the objective (ui) with the decision variables to facilitate the optimization process. the advanced nonlinear regression (hookjeevs pattern moves) was implemented with aid of computer program (statistica version10).the non-linear objective function is: ui=0.184vg -0.214 ρs 0.12 dp -0.267 … (3) subject to inequality constraints: eq. (3) represents the global optimization problem equation of three positions in the spouted bed. optimization search depends on fitness function, which is first derived from the objective function and is used in successive genetic operations. the enhancement of uniformity of solid particles in spouted bed using stochastic optimization 28 ijcpe vol.16 no.3 (sept. 2015) -available online at: www.iasj.net fitness function is a blend of objective (eq.3) and constraint function (eq.4).optimization problem is solving by using matlab version r2012a. results and discussion 1effect of solids distributions figs. (7 and 8) explain samples of optical probe signals for non-uniform distribution of small glass beads and uniform distribution of large steel beads. figs.(9 and 10) illustrate the solid concentration distributions in the spouted bed for different positions and flow regimes.vg was ranged between 0.74 to 1.0 m/s for glass and steel beads .the solid concentration of steel beads (fig.10) is higher than that of glass beads (fig.9) because of high density of steel beads. position 1 indicates to fountain region at which the solid concentration profile has pulse shape. instability of fountain region is due to high vortex of flow and interaction of solid particles for different flow regimes compared to stable conditions appeared at annuals region (positions 2 and 3) as shown in fig.7, optical probe signals of nonuniform solids distributions fig.8, optical probe signals of uniform solids distributions fig.9, solids concentration distribution of glass beads figs.(9 and10). the solid concentration profiles have uniform exponential form at annulus region for the same flow regimes. the spoutedair bed behaves as hybrid gas-solid system. performance of the spouted bed is dropped at unstable conditions as explained by [9] and [10].a stable bed is observed when the particles fluidized homogenously as shown in figs. (8, 9 and 10). ghanim.m. alwan -available online at: www.iasj.net ijcpe vol.16 no.3 (sept. 2015) 29 fig.10, solids concentration distribution of steel beads the solid concentration is much less in the lean bed region at the center than in the dense bed region near the wall as shown in figs.( 9 and10). this reduces heat and mass transfer and reactants conversion. therefore, in case of spouted bed reactor, the unconverted concentration of material at the center is higher than that at the spouted wall. 2effect of decision variables on ui fig.(11) illustrates the effect of air velocities on ui for steel and glass beads. ui was decreased with increasing air velocity (vg) because of increasing of desperation of solid particles due to the kinetic energy of the solid particles is increased.in addition, two regions are appeared in these curves, which represent the transition region from packed bed flow regime at vg of 0.74 m/s to stable spouting flow regime at vg of 0.95 and 1.0 m/s.ui of steel beads is higher than that of glass beads as shown in figs. (9 and 10) because of high scattering was occurred with the particles of low density. low concentrations of solid particles were obtained for all positions with the glass beads system, which would affect on values of ui.density of solid particles has positive effect on ui across the spouted bed (fig. 12). fig.11, uniformity index versus gas velocity fig.12, uniformity index versus solid density and solid diameter increasing of the particles' density could provide the bed more strength and resistance against vortex of the fountain. therefore, it gives the solid particles more stability and uniformity. the denser material is continued to spout in the central region while the less dense particle formed vortex around the central spout. the solid enhancement of uniformity of solid particles in spouted bed using stochastic optimization 30 ijcpe vol.16 no.3 (sept. 2015) -available online at: www.iasj.net beads diameter has negative effect on ui of the solid particles as shown in fig.(12). the particles of small size are helpful to raise the mixing speed .this provides the smaller particles more uniformity in the radial distribution.this was concluded by [11]. however, the uniformity of particles will enhance heat and mass transfer, and conversion of reactants in the bed because of improving of holdup and voids distributions of solids. 3optimization search the spouted-gas bed is nonlinear hybrid system as explained in sections (3.2 and 4.1). hence, genetic algorithm (ga) is the suitable global stochastic search for solving optimization problem.ga is the most popular form of evolutionary algorithm. a population of chromosomes represents a set of possible solution. these solutions are classified by an evaluation function, giving better values, or fitness to better solutions as explained by [12]. the operators of genetic algorithm search were adapted to obtain best results. table (2) explains the best parameters of the genetic algorithms. fig. (13) illustrates the results of ga search. ga implemented with the pattern search by using the hybrid function as shown in table (2) to refine the decision variables as explained by [13]. table 2, adapted parameters of ga parameter type/value population type double vector population size 80 creation function feasible population scaling function rank selection function roulette crossover function scattered crossover fraction 0.8 mutation function adaptive feasible migration direction forward migration fraction 0.1 hybrid function pattern search number of generation 51 function tolerance 1.0e-6 the best fitness, best function and score histogram as shown in fig.13 illustrate that the optimal ui is (0.534).the results of the optimization search (table 3) have reasonable agreement because of values of decision variables (vg , ρs and dp) are within the limits of operating conditions (eq. 4). in addition, the maximum ui could be obtained by low gas velocity, high-density steel beads of low particle diameter as shown in table (3) and fig.(13). therefore, by staying close to this minimum flow condition, it is possible to perform a stable operation and to obtain energy savings. also [14] concluded this. the histogram of the variables in fig. (13) indicates that the density of solids (variable 2) is the effective variable on ui. due to the nonlinearity of the spouted process (eq. 3), the optimization equation of ui was solved by (51) generations as shown in fig.(13). ghanim.m. alwan -available online at: www.iasj.net ijcpe vol.16 no.3 (sept. 2015) 31 fig.13, stochastic results of ga search table 3, optimal values of decision variables decision variables optimum value gas velocity (m/s) 0.74 density of solid (kg/m 3 ) 6648 diameter particle (mm) 1.09 optimum results could guide the experimental work and enhance uniformity of solids across the bed as shown in fig.(14).performance of the bed would be improved. success of optimization search depends on formulation of objective function, selection of decision variables and selection of suitable searching technique. fig.14, improving of solids uniformity at optimum operating conditions 4stochastic mutation of decision variables the optimal sets of the three decision variables are illustrated in figs.(15a, 15b and 15c) are corresponding to ui mutations. the scattering and enhancement of uniformity of solid particles in spouted bed using stochastic optimization 32 ijcpe vol.16 no.3 (sept. 2015) -available online at: www.iasj.net stochastic results are appeared behaviors of variables because of natural selection by ga .it is found that the optimal values of solid density (ρs) are stay within its upper bound as shown in fig. (15b). gas velocity (vg) and solid diameter (dp) are changed within its lower bounds (figs. 15a and 15c).these behaviors are because of ρs has positive effect while vg and dp have negative effect on ui as shown in figs.(11 and 12). most optimal values of the three decision variables are stayed within optimum value of ui, which equal to (0.534) as shown in fig.(13).it is observed that vg and dp are more sensitive variables for ui mutations as shown in figs. (15a and 15c). conclusions uniformity of solid particles enhances performance of the spouted bed. hydrodynamic parameters, heat and mass transfer in the bed would be increased because of improving of hold-up and voids distributions of solids. optimization search could guide the experimental work and would select best operating conditions. ga has been found suitable global search for the hybrid nonlinear spouted bed. reliability of the search could be increased by adaptation of genetics' operators. success of optimization search depends on formulation of objective function, selection of decision variables and selection of suitable searching technique. reasonable results have been obtained when compared optimal values with experimental data. maximum uniformity has been observed with high-density steel beads of low particle's diameter at low gas velocity. density of solid particles is the effective variable on uniformity distributions of beads across the bed. optimal velocity of spouted gas and diameter of solid particles are the sensitive decision variables corresponding to ui mutations. (a) (b) (c) fig.15, stochastic mutations of decision variables with objective ui ghanim.m. alwan -available online at: www.iasj.net ijcpe vol.16 no.3 (sept. 2015) 33 nomenclatures c: relative concentration of solid particles,[-] dp: diameter of solid particle, [mm] v: optical signal,[volt] vg: superficial velocity of gas, [m/s] greek symbols ρs: density of solid particles,[kg/m3] €: porosity of bed, [-] ø: sphercity of solid particle,[-] acknowledgments we thank all the participants to chemical and biological department, missouri university of s & t, rolla, usa, for supporting this work. especial thanks to professor dr.muthanna al-dahhan, head of the department. references 1sahoo,p. and a.sahoo(2013);" fluidization and spouting of fine particles: a comparison", advances in materials science and engineering journal, article id 369380, 13. 2rovero,g.,massimo,c.,and c. giuliano(2012);"optimization of a spouted bed scale-up by square based multiple unit design",advances in chemical engineering,chapter16, published with intech, isbn: 987-953-510392-9. 3limtrakul, s., boonsrirat, a.and vatanathm, t (2004);"dem modeling and simulation of a catalytic gas solid fluidized bed reactor: a spouted bed as acase study", dept.of chem.engng.kasetsar ,university, bangkok, thailand, elsevier ltd. 4wang, z., chen, p., li, h., wu, c.andchen, y (2001);"study on the hydrodynamics of a spouting moving bed",ind.engng.chem.res, 40, pp.4983-4989 5prachayawrakorn, s., reuengnarong, s.and soponronnarit,s(2005);"characteris tics of heat transfer in twodimensional spouted bed", school of energy and materials, university of technology,bangkok, thailand. 6xu,j.,bao,x.wei,w.,bi,h.t.,grace, j.r.,and lim,c.j.(2009),"chaotic characteristics of pressurefluctuation in a gas spouted bed", the canadian journal of chemical engineering, vol.87, april. 7hao, h., guoxin, h.and fengchao, w.(2008);"experimental study on particles mixing in an annular spouted bed", energy and conversion management, 49,257266, elsevier. 8nedeltchev,s.,ookawara,s.,and ogawa,k.(2000);"time-dependent mixing behaviors in lower and upper zones of bubble column", j.chem.engng.of japan, vol.33, no.5, pp.761767. 9zhang, y., zhong, w.and jin, b(2011);"new method for the investigation of particle mixing dynamic in a spout-fluid bed", powder technology, 24, january. 10alwan,g.m.(2012);" experimental study of distribution and stability of solid particles in spouted bed", proceedings of international conference on engineering and information technology“iceit2012” sep. 1718, toronto, canada isbn: 978-177136-064-7. 11alwan, g. m., aradhya, s.b and al-dahhan,m.h (2014);" study of solids and gas distribution in spouted bed operated in stable and unstable conditions", international. journal of engineering research and applications, 4, issue 2, 01-06. iraqi journal of chemical and petroleum engineering vol.16 no.1 (march 2015) 4962 issn: 1997-4884 desulfurization of gas oil using a solar photocatalytic microreactor mohammad fadhil abid chemical engineering department, university of technology, baghdad, iraq abstract the present work is devoted to investigate the performance of a homemade y-shape catalytic microreactor for degradation of dibenzothiophene (dbt), as a model of sulphur compounds including in gas oil, utilizing solar incident energy. the microchannel was coated with tio2 nanoparticles which were used as a photocatalyst. performance of the microreactor was investigated using different conditions (e.g., dbt concentration, lhsv, operating temperature, and (h2o2/dbt) ratio). our experiments show that, in the absence of uv light, no reaction takes place. the results revealed that outlet concentration of dbt decreases as the mean residence time in the microreactor increases. also, it was noted that operating temperature showed a positive impact on the degradation rate of dbt while lhsv showed a different image. the results reported an optimum (h2o2/dbt) ratio which gave maximum conversion of dbt which vary with initial concentration. kinetic study was carried out which confirmed that desulfurization of dbt followed a pseudo-first order reaction at 30 and 50 o c, respectively. however deviation from linearity was observed at 60 o c. comparison between microreactor´s performance and performance of batch reactors from published literature were illustrated. the comparison confirmed the unique characteristics of the microreactor. key words: microreactor, solar energy, photocatalysis, desulfurization, dibenzothiophene introduction crude oil is the largest and most widely used source of energy in the world. major portions of the crude oils are used as transportation fuels such as gasoline, diesel and jet fuel. however, such crudes contain sulfur, typically in the form of organic sulfur compounds. the sulfur content and the api gravity are two properties which have a great influence on the value of the crude oil. the sulfur content is expressed as a percentage of sulfur by weight and varies from less than 0.1% to greater than 5% depending on the type and source of crude oils [1]. combustion of gasoil and diesel fuel has been identified as one of the major emission sources of polyaromatic hydrocarbons (pah) in urban areas. as environmental consciousness rises, all countries worldwide introduce more stringent legislation to limit the pah content of diesel fuels. in the foreseeable future, a sulfur content as low as 10 ppm and a pah content not greater than 2% may be proposed in most countries worldwide. iraqi journal of chemical and petroleum engineering university of baghdad college of engineering desulfurization of gas oil using a solar photocatalytic microreactor 50 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net furthermore, the sulfur compounds are taken into account as the components of pah. dibenzothiophene (dbt) and its derivatives are the major sulfur species in diesel and gas oil [2]. currently, hydroesulfuizaion (hds) is used to remove sulfur from hydrocarbons in petroleum refineries which require either increasing reactor residence time, or carrying out reactions in sever conditions [3]. the catalysts used in hds are not active in removing refractory sulfur compounds, such as dibenzothiophenes (dbts) and its derivatives, and these compounds require higher hydrogen consumption in the hds process [1]. in the past few years, microreactor technology is presented as a novel and breakthrough technology on which the new concept of production and research will be built upon. the chemical industry, biotechnology, pharmaceutical industry and medicine, life science, clinical and environmental diagnostic are just some of the small fields where this new concept in production, analysis and research could find its place of application [4]. by decreasing the equipment size by several magnitude levels, substantial economic benefits, improvement of intrinsic safety, and a reduction of environmental impact can be achieved [5]. the large surface area, per volume, gives high thermal conductivity to a micro-channel allowing quick and accurate temperature control of the chemicals inside [6]. recent reports have demonstrated that a vast range of organic reactions including the aldol reaction [7], the synthesis of esters [8], the hantzsch synthesis [9], and fluorinations [10], chlorination [11] and brominating [12] can be performed within microreactors. microreactors can be manufactured from metal, glass, and a range of polymeric materials [13]. a number of techniques may be used to create the required network of microchannel, including photolithographic, moulding, embossing and milling processes [14]. in the field of bio-catalysis, drott et al. [ 15 ] have investigated the use of porous silicon as a carrier matrix in microstructured enzyme reactors, increasing the surface area onto which enzymes could be coupled, using the microreactor fabricated at 50 ma/cm 2 current density, they found that the enzyme activity was increased 100fold compared with the reference reactor. chambers et al. [16] have reported the development of a microreactor in which elemental fluorine has been used to allow both the selective fluorination and per fluorination of organic compounds in a simple controllable manner. the synthesis of fluorine-containing organic compounds has many inherent safety issues such as safe handling and temperature control.( chambers et al. [16] outlined the potential benefits of the microreactor used as being ( i ) a small inventory of fluorine in the reaction zone, ( ii ) an opportunity for good mixing and temperature control and ( iii ) simple reaction scale-up. kelly et al. [17] developed a system of a microreactor in combination with a micro fuel cell as an alternative to conventional portable sources of electricity such as batteries due its ability to provide an uninterrupted supply of electricity as long as a supply of methanol and water can be provided. they proved that the energy storage density per unit volume/weight of this system was higher than that of batteries, which translates into less frequent recharging through the refilling of methanol fuel. the large surface area, per volume, gives high thermal conductivity to a microchannel allowing quick and accurate temperature control of the chemicals inside [6]. there are a lot of chemical mohammad fadhil abid -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 51 systems using micro-channels. many of them are made of transparent material, such as glass, plastics, or silicone rubber, so the researchers can visually observe the reactions [18, 19]. the desulfurization reaction is most often considered as a pseudo 1st order rate reaction [20]. the pseudo 1 st order approximation is associated with the overall degradation reaction of dibenzothiophene which may be assumed to consist of the following steps [20], activation of substrate: t + hv t* ……………(1) activation of oxidant: h2o2 + hv h2o2 * ……(2) substrate conversion with activated oxidant: t * + oh * products …. (3) where t and hv represent the organic substrate and uv photon energy, respectively. in the above degradation pathway, all the radicals formed by the collision of one photon and one molecule of h2o2 are included in the term h2o2*. h2o2 itself does not oxidize dbt in the absence of uv light; but it helps the excited dbt molecules to be oxidized [21]. the aim of the present work was to investigate the desulfurization of gas oil utilizing a solar photocatalysis microreaction process. influence of the operating variables such as initial sulfur content, inlet mixture flow rate, and h2o2 loadings on reactor performance was investigated. in addition, the kinetic parameters of the desulfurization process were estimated. materials and methods materials the chemicals which have been used in this work are: titanium dioxide ((tio2, 80% anatasa) of size (5-30nm) (specific surface area 60±15 m 2 /g (bet), was obtained from zhengzhou xinyue chemical co., china.). dibenzothiophene (purity 97%, from riedel-de haën ag, germany) was used as a model for the sulfur containing compounds in the fuel. nhexane (purity 85%) was used as a carrying medium inside the microreactor for dibenzothiophene. nhexane was obtained from merck millipore, malaysia. deionized water and acetonitrile from labscanpoland were used as a mobile phase in the hplc. the mobile phase prepared from (70% acetonitrile, 30% water). the hydrogen peroxide solution which is used as the oxidizing agent (purity35%) was obtained from merckgruppe, germany. all chemicals are hplc grade and were used as received without further purification. microreactor design and fabrication for the design of a micro reactor, it has to be considered that both heat and mass transport time-scales are strongly correlated with the characteristic dimensions of the microreactor according to diffusion theory [22, 23]: heat transport: t ~ l 2 /a ~ l/u ……..(4) mass transport: t ~ l 2 /d ~ l/u…….(5) l 2 / a. t = l 2 .u/ a.l ~ 1…………….(6) l 2 /d.t = l 2 .u/ d.l ~ 1………………(7) where l: travelling length, t: time-scale, l: diffusion length, a: thermal diffusivity of fluid, d: mass diffusivity, u: flow speed desulfurization of gas oil using a solar photocatalytic microreactor 52 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net the first step is diffusing to a reactive surface followed by the reaction. the diffusion time is one of the principal factors on how fast conversion can be accomplished. various approaches haven applied to simulate the flow in different types of microreactor and to estimate the optimum dimensions [24-26]. to estimate the main dimensions of the microreactor (i.e., width and length of the microchannel and the angle between the lateral channel and the central line of the main channel), the governing equations for the fluids (i.e., continuity, momentum, and concentrations) are solved using matlab version 7. the physical properties, operating parameters of the system (d, μ, ρ, a, and u), and equations (6) and (7) are inserted together with the required boundary conditions to obtain the optimum dimensions. y-shape microreactor was drawn using 2d autocad and fabricated using surfcam software on cnc milling machine type c-tek. the schematic diagram shown in fig. 1 displays the dimensions of the reactor pattern. this reactor design has the advantage of independent control and monitoring of the reactant and product streams. it also provides in situ mixing of reactants, thus avoiding some of the hazards associated with a premixed feed. the mixing efficiency of the yjunction depends on flow rates, nature of the reactant molecules and channel aspect ratio (width/height). fig. 2 shows the microreactor which was fabricated in the training and workshops centre-university of technology. the upper and lower parts of the reactor were made of transparent elastic polydimethylsiloxane (pdms) and aluminium alloy, respectively. a transparent flexible gasket was inserted between the two parts before bolted with each other. fig. 1, dimensional schematic of the microreactor pattern (all dimensions are in mm) mohammad fadhil abid -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 53 (a) (b) fig. 2, disassembly of the microreactor (a) upper part, (b) lower part catalyst deposition of nano-tio2 particles on microchannel of the aluminium plate, in the present research was performed as follows: 1. in a beaker, 1.5 ml of a dilute nitric acid solution (ph = 3.5) and 4.5 ml of 50% ethanol and 0.5 g nano-tio2 powder were added while stirring by a magnetic stirrer at 300 rpm. before deposition, the surface was washed in a basic solution of naoh in order to increase the number of oh groups. 2. after 15 minutes of stirring, a given volume suspension was carefully injected in the microchannel using a 5-ml syringe. the suspension filled the microchannel and allowed to dry at 80 ◦ c for six hours. 3. the coated sample was then annealed for 30 minutes at 350°c. during the heating, oh groups from the catalyst surface and the support can react and lose a molecule of water, creating an oxygen bridge, thus increasing the adherence of the catalyst to the support. 4. this deposition process could be carried several times in succession so as to increase the total thickness. microchannel was scanned using sem (model inspect s50, s/n 9922650, fei company, usa) to investigate the effect of successive coatings on microchannel as shown in figure 4. the first coat does not cover the entire surface but additional coats lead to a complete coverage. scanning procedure was carried out at the applied sciences department-university of technology. (a) (b) fig. 3, effect of successive coating of microchannel with nanotio2, after first coating (a) and after third coating (b) desulfurization of gas oil using a solar photocatalytic microreactor 54 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net experimental setup figure 4 presents a schematic diagram and a photographic view of the experimental setup is shown in fig.5 (a, and b). fig. 4, schematic of the experimental setup (a) (b) fig. 5, photographic view of the setup (a) and the microreactor (b) a solution of certain concentration of dibenzothiophene in hexane was prepared and contained in a 250 ml graduated glass serum container connected to a micropump via a regulating valve. another 250 ml graduated glass serum container filled with a 30% hydrogen peroxide solution was connected to a second micropump. the two containers were installed on a magnetic stirrer supplied with an electric heater to keep the homogeneity of the mixture in a steady form and heating the feeds to a desired initial temperature. valves were calibrated with the level in each container so different flow rates could be delivered to the microreactor separately in each run. each micropump manufactured by williamson company limited, model number 200.015.230.016 was used to deliver the feed (reactants) to the microreactor. effluent of the microreactor was collected in a graduated 250 ml container surrounded by a cold water bath. just at the exit of the microreactor the experimental setup was supplied with a valve for instantaneous sampling. the sample was centrifuged to separate the water contained in h2o2 and the upper solution was injected to the hplc (hplc–uv; agilent technologies 1100; a c-18, (25 cm x 4.6 mm i.d.) stainless steel column (packed with zorbax 8-μm, odsbound, spherical, silica particles) and was used with a mobile phase consisting of 70% acetonitrile and 30% water flowing at a rate of 1ml/min) to find out the unreacted dibenzothiophene concentration in hexane. all containers and tubing outside the microreactor were shielded from uv-exposure. flowrates of 0.75, 1, 1.5, 2 l/min were used which correlate to 8.1, 6.1, 4, 3min residence times. the fractional degradation (x) of dbt was calculated by eqn. 8: fractional degradation (x) = (coc(t))/co …(8) mohammad fadhil abid -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 55 procedure to analyze the dibenzothiopene concentration, an hplc was used in this study. a series of dibenzothiophene/hexane solutions at concentrations of 20, 50, 100, 200, 300, and 500 ppm are used to generate calibration curves. before analysis, each solution was diluted by a factor of 1:10; this dilution is done because of the limitations in the hplc. similar analytical methods used by others use a mobile phase of acetonitrile and water, acetonitrile, tetrahydrofuran, and water, or methyl hydroxide and water [27]. in the present work, the mobile phase used was 70:30 acetonitrile to water ratio with the c-18 column on hand. figure 6 shows a chromatograph of dibenzothiophene of 400 ppm concentration in hexane with a retention time of 9.93 min. the calibration curve of the dibenzothiophene/hexane solution for area vs. concentration (ppm) is shown in fig. 7 this curve correlate a given peak area with a known concentration. fig. 6, chromatograph of dibenzothiophene fig. 7, calibration curve of dibenzothiophene area = 2625.8c r² = 0.9967 0 200000 400000 600000 800000 1000000 1200000 1400000 0 100 200 300 400 500 600 a re a dbt concentration, [ppm] desulfurization of gas oil using a solar photocatalytic microreactor 56 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net results and discussion influence of solar incident energy on desulfurization process to investigate the influence of the incident solar energy on reaction mechanism of dbt, an amount of 500 ppm of dbt in hexane solution that was used as the feed to the microreactor was mixed with an equal amount of 30% hydrogen peroxide solution and placed in a serum bottle. the bottle is kept at a temperature of 5°c for three hours in a cold water bath. the concentration of dbt in hexane was followed with time as shown in fig.8. fig. 8 indicates no apparent change in the concentration of dbt and this revealed that the desulfurization reaction was taking place only inside the microreactor where the materials were illuminated by the uv light. this finding supports and proves that the suggested reaction mechanism that hydrogen peroxide itself does not directly oxidize dibnezothiophene for sulfur removal but it helps the photo excited dibenzothiophene to be oxidized. fig. 8, concentration of dbt in hexane vs. time for a sample of stoichiometric ratio of h2o2:dbt in a container at 10 o c and co=500 ppm dbt influence of concentration of dbt figure 9 represents the experimental results conducted for dbt desulfuraization at different space times. again, it is observed that the outlet concentration decreases as the mean space time inside the microreactor increases. this confirms the fact that if the dbt stays longer in the reactor, its conversion increases as the space time increases. the effect of initial concentration of dbt solution on dbt degradation efficiency has been investigated by varying the dbts concentration from (100 to 500 ppm). fig. 9 also plots the variation of dbts degradation against residence time in the presence of tio2 nanoparticles under solar light. as can be seen from fig. 9 that after 8.1 min of irradiation time the degradation was 65%, 58%, and 40% at dbt concentrations of (100, 300, and 500 ppm), respectively. dbt degradation rate was observed to decrease as initial concentration increased. fig. 9, variation of dbt conversion against residence time at different concentrations of dbt, initial temperature= 50 o c,(h2o2/dbt)=1 mohammad fadhil abid -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 57 influence of initial temperature and lhsv fig. (10), illustrates the effects of reaction temperature and space velocity of the influent stream on the reduction of dbt. an increase in the reaction temperature was observed to result in increased removal of dbt. the effect of temperature was to increase the specific rate constant which pronounced the conversion. as can be seen from fig. 10, the removal of dbt was shown to decrease markedly as lhsv of the influent stream increased this may be due to the retention time during the oxidation process which was reduced. fig. 10, effect of initial temperature and lhsv on dbt conversion (dbt concentration =100 ppm, (h2o2/dbt) =1) influence of molar ratio of h2o2/dbt fig. (11), shows the variation of normalized dbt concentration against h2o2/dbt ratio in solution, keeping all other parameters unchanged. different (h2o2 /dbt) ratio (1 to 6) was used to study the effect of h2o2 concentration on the desulfurization rate. as can be seen, the removal rate increased with increasing initial concentration of h2o2 at fixed concentration of dbt. the desulfurization rate was slow at low h2o2 concentration, as the formation of hydroxyl radicals was insufficient; this may be explained by the ability of h2o2 to trap the electrons, preventing the electron-hole recombination and hence increasing the chance of formation of oh* radicals on the surface of the catalyst [28]. however, at a dbt concentration of 100 ppm, as the h2o2/dbt ratio increased beyond a certain limit, (4), the increased decomposition rate became noticeably less. this trend was also observed for dbt concentration of 300 and 500 ppm but at a h2o2/dbt ratio of 5 and 6, respectively. this was because at higher h2o2 concentration, more oh* radicals were produced leading to a faster oxidation rate. however, these excess free radicals were more prone to react with the excess h2o2 rather than with the dbt [29]. one form of this effect can be seen through shortcirculating the semiconductor microelectrode [30], according to eqn. (9) and (10): h2o2 + oh * →h2o+ho2 * ….. (9) ho2 * + oh * →h2o+o2 …… (10) fig. 11, variation of normalized concentration against (h2o2/dbt) at different dbt concentrations desulfurization of gas oil using a solar photocatalytic microreactor 58 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net therefore, it is imperative to determine the stoichiometric amount of hydrogen peroxide sufficient for complete mineralization. this analysis was not presented in the present work. kinetics study kinetics studies were carried out under optimal reaction conditions. the rate constant for the apparent consumption of dbt was obtained from the pseudo first-order eqn. 11: r = −dc/dt = kc = k1 co (1-x) …..(11) r = cao dx/dt = k1co (1-x)……. (12) eqn. 12 can be integrated between t= 0 and t= t, yielding: ln (1-x)= -k1t…………………… (13) where x is the fractional degradation of dbt, t is the residence time (min), k1 is the first-order rate constant (s -1 ), co is the initial concentration of dbt, and r is the reaction rate (mg dbt/cm 3 cat. s). when (-ln (1-x)) was plotted against t, a straight line was fitted to the data of fig. 12 at 30 o c and 50 o c with correlation coefficient (r 2 ) of 0.99 and 0.98, respectively. this suggested that dbt photo degradation reaction followed pseudo first-order kinetics. the reaction rate constants were found to be 1.17x10 -3 s -1 and 1.76x10 -3 s -1 at 30 o c and 50 o c, respectively. however, it is worth to mention that as operating temperature increased above 50 o c, a deviation from linearity trend of reaction order is resulted as reported in table 1. table 2 lists data related to the results of present work and to the information extracted from published literature. fig.12, [–ln(1-x)] against residence time at different temperatures for kinetic study analysis, cdbt =100 ppm and (h2o2/dbt) =4 table (1), results of kinetic study at cdbt =100 ppm and (h2o2/dbt) =4 no. temperature reaction rate law (mg/g-cat.s) 1 30 1.17*10 -3 c 2 50 1.76* 10 -3 c 3 60 2.16*10 -3 c 1.15 table 2: data related to the results of present work and to the information extracted from published literature substrate desulfurization process rate constant, s -1 reactor type reference dbt oxidative (30%h2o2)+uv lamp 2.86x10 -5 (at 50 o c) batch reactor shiraishi et al. [31] dbt oxidative (30%h2o2)+uv lamp 1.61x10 -3 (at 25 o c (l. c. model sl-3) microreactor al-raie [24] dbt oxidative (30%h2o2)+uv lamp 3.5x10 -5 (at 50 o c) batch reactor hirai et al. [21] dbt solar photocatalysis 1.17x10 -3 (at 30 o c) y-shape microreactor present work mohammad fadhil abid -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 59 comparison with other researchers´ works fig. 13 illustrates the comparison of the results obtained by other researchers for desulfurization of dibenzothiophene with the performance results obtained in the microreactor of the present work, and table 3 summarizes the results obtained with different authors. curve of gemma [32] shows the profile of dibenzothiophene desulfurization by enzymatic effect of manganese peroxidase (mnp) on a 6 mg/l of dbt in a 100 ml batch reactor operated at 22 o c. the degradation profile shows a conversion of 39% achieved after 8 hours of bio-treatment. curve of shiraishi et al. [31] shows the concentration profile for dibenzothiophene desulfurization with 30% hydrogen peroxide and solar uv light at λ > 280 nm in a batch reactor. a conversion of 82% is achieved after 8 hours of irradiation. the curve of the present work shows a conversion of 65% achieved after 8.1 minutes of irradiation. it is evident from table 3 that the microreactor was much more efficient for the desulfurization of dibenzothiophene as was anticipated due to understanding the advantages of microreactors. fig. 13, comparison between microreactor´s performance and performance of batch reactors of shiraishi et al. [31] and gemma [32] table (3), comparison between microreactor´s performance and performance of batch reactors of shiraishi et al. [31] and gemma [32] substrate process type of reactor retention time conversion % reference dbt h2o2 +uv lamp batch 480 min 82 [31] dbt bioprocess batch 480 min 39 [32] dbt solar photocatalysis yshape micreacto 8.1 min 65 present work conclusion recently, microreactor technology is presented as a novel and breakthrough technology on which the new concept of production and research will be built upon. in the present study desulfurization of dibenzothiophene in a solar photocatalysis microreactor was investigated. results show that, in the absence of uv light, no reaction takes place. experiments confirmed that the outlet concentration of dbt decreases as the mean residence time in the microreactor increases. this is obvious because as dibenzothiophene remain longer in the reactor and thus their conversion increase with time. the reaction rate constant (k) was determined and found to be of the order of 10 -3 (s -1 ) for dibenzothiophene desulfurization. when this result is compared to reaction rate constants reported by other investigators we find that this reaction proceeds much desulfurization of gas oil using a solar photocatalytic microreactor 60 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net slower in a batch reactor than in the microreactor. the degradation reaction of dbt exhibited a first order behaviour at 30 and 50 o c, respectively. however the image was different at 60 o c. this revealed the effect of temperature on the reaction order of desulfurization reaction. the experimental results obtained from the microreactor study were compared with the work reported by other researchers in this field. it was found that the microreactor is much more efficient than batch reactors for the desulfurization process of dibenzothiophene. this is an anticipated outcome based on the understanding of the advantages of microreactors in performing reaction processes in which mass transfer components play important role. in this study the microreactor was capable of achieving a 65% conversion of dbt in approximately 8.1 (min) which compares to approximately 340-500 (min) for a macroscopic batch reactor operation. acknowledgement the author is thankful to the department of chemical engineeringuniversity of technology for providing facilities and space where the present work was carried out. the author acknowledged the support of technical staff of the training and workshops centreuniversity of technology. nomenclature a thermal diffusivity of fluid ( cm 2 /s) c instantaneous concentration of dbt (ppm) co initial concentration of dbt (ppm) d mass diffusivity (cm 2 /s) dbt dibenzothiophene hv uv photon energy (j) hds hydrosulfurization k1 reaction rate constant (s -1 ) l diffusion length (cm) l travelling length (cm) l.c. liquid cell pah polyaromatics r reaction rate of dbt (mg dbt reacted/ gm catalyst. s) sem scanning electron microscope t time-scale (s) t organic substrate of equation (1) t* organic substrate activated by uv photon u flow speed (cm/s) x fractional degradation of dbt references 1. fadhel z. s., desulfurization of light diesel fuel using chloramine t and polymer supported imidation agent, msc thesis, chemical engineering department, university of technology, baghdad (2010). 2. ting-mu c., chih-ming w., ikai w., tseng-chang t., promoter effect of vanadia on co/mo/al2o3 catalyst for deep hydrodesulfurization via the hydrogenation reaction pathway. journal of catalysis 272 (2010) 28–36. 3. al-malki a., desulfurization of gasoline and diesel fuels, using non-hydrogen consuming techniques, m.sc. thesis, king fahad university of petroleum and minerals, october, (2004) 4. anita š., ana t., bruno z., review: application of microreactors in medicine and biomedicine, journal of applied biomedicine. 10: 137–153, 2012. 5. rebrov e.v., duinkerke s.a., croon m.h.j.m., schouten j.c., optimization of heat transfer characteristics, flow distribution, and reaction processing for a microstructured reactor/heatexchanger for optimal performance mohammad fadhil abid -available online at: www.iasj.net ijcpe vol.16 no.1 (march 2015) 61 in platinum catalyzed ammonia oxidation. chem eng j. 93: 201– 216, 2003. 6. kusakabe k., j. of chem. eng. of jpn, vol. 35, no. 9, pp. 914-917, (2002) 7. wiles c., p. watts, s. j. haswell and e. pombo-villar, the aldol reaction of silyl enol ethers within a micro reactor, lab on a chip, 2001, 1, 100-101 8. wiles c., p. watts, s. j. haswell and e. pombo-villar, solution phase synthesis of esters within a micro reactor, tetrahedron, 2003, 59, 10173-10179. 9. garcia e. e., s. y. f. wong, b. h. warrington, a hantzsch synthesis of 2-aminothiazoles performed in a microreactor system, micro total analysis systems 2001, ,proceedings of the µtas 2001 symposium, held in monterey, ca, usa 21–25 october, 2001.p 517518,editors: j. michael ramsey, albert van den berg. 10. hideki a., aiichiro n. and jun-ichi y., flow microreactor synthesis in organo-fluorine chemistry, beilstein j. org. chem. (2013), 9, 2793–2802. 11. matsubara h., y. hino, m. tokizane, and i. ryu, microflow photo-radical chlorination of cyclohexane, chemical engineering journal, (2011), 167(2-3); 567-571, 12. löwe h., bromination of thiophene in micro reactors, letters in organic chemistry , 11/2005; 2(8):767-779, bentham science publishers. 13. wang y., editor, and holladay j. d., editor, microreactor technology and process intensification, acs symposium; 914, (2003), isbn 0-8412-3923-1 14. yuan-chien t., shung-jim y., hsun-tsing l., hsiu-ping j. and you-zung h., fabrication of a flexible and disposable microreactor using a dry film photoresist, journal of the chinese chemical society, (2006), 53, 683688 15. drott j., k. lindstrom, ,l. rosengrent, t. laurell, j. micromech. microeng. 7 (1997) 14-23, uk. 16. chambers, r. d., and spink, r. c. h., microreactors for elemental fluorine, chem. commun. (1999) 883. 17. kelly s., g. deluga, and w. smyrl, miniature fuel cells fabricated on silicon substrates, aiche., vol. 48, pp. 1071-1082, (2002) 18. fujinami m., m. tokeshi, t. odake, t. kitamori, sato k., t. sawada, k. matsumoto, m. nakao, t. ooi, and y. hatamura, microfabricated channels and fluid control systems for integrated flow injection analysis, micro total analysis systems 1998, pp. 339-342 (1998) 19. takeshi o., okabe y., m. nakao, and k. iwata, laminated electrodes chips for pulseimmunoassay, micro total analysis systems 2002, pp. 121123 (2002). 20. ] arantegui j., prado j., chamarro e., and esplugas s., kinetics of the uv degradation of atrazine in aqueous solution in the presence of hydrogen peroxide, j. photochem. photobiol. a: chemistyr, 88 (1995) 65-74. 21. hirai t., k. ogawa, y. shiraishi, and i. komasawa, effect of photosensitizer and hydrogen peroxide on desulfurization of light oil by photochemical reaction and liquid-liquid extraction, ind. eng. chem. res., (1997), 36, 530-533. 22. wegeng r.w., call c.j. and drost m.k., proc. 1996 spring national http://link.springer.com/search?facet-author=%22e.+garcia-egido%22 http://link.springer.com/search?facet-author=%22s.+y.+f.+wong%22 http://link.springer.com/search?facet-author=%22b.+h.+warrington%22 http://link.springer.com/search?facet-author=%22b.+h.+warrington%22 http://link.springer.com/search?facet-author=%22j.+michael+ramsey%22 http://link.springer.com/search?facet-author=%22albert+van+den+berg%22 http://www.researchgate.net/profile/loewe_holger http://www.researchgate.net/journal/1570-1786_letters_in_organic_chemistry desulfurization of gas oil using a solar photocatalytic microreactor 62 ijcpe vol.16 no.1 (march 2015) -available online at: www.iasj.net meeting, aiche, feb. 25–29 new orleans, seiten 1–13. 23. branebjerg j, gravesen p., krog j.p., and nielsen c.r., proc. ieee mems ‘96, san diego,usa (1996) 24. ali h. al-raie, desulfurization of thiophene and dibenzothiophene with hydrogen peroxide in a photochemical microreactor, msc thesis, oregon state university, 2005 25. wang x., hirano h, xie g., and ding x., vof modeling and analysis of the segmented flow in y-shaped microchannels for microreactor systems, advanced in high energy physics, vol. 2013, article id 732682,1-6 26. yong k. s., and sangmo k., a review on mixing in microfluidics, micromachines 2010, 1, 82-111 27. mezcua m., amadeo r. f., antonio r., karina b., pedro l., and eloy g. c., chromatographic methods applied in the monitoring of biodesulfurization processesstate of the art, talanta, 73 (2007): 103-114. 28. wang y., and hong c.s., "effect of hydrogen peroxide, periodate and persulfate on photocatalysis of 2-chlorobiphenyl in aqueous tio2 suspensions", water res., vol. 33, 9, (1999), 2031-2036. 29. dixit a., mungray a. k., and chakraborty m., photochemical oxidation of phenol and chlorophenol by uv/h2o2/tio2 process: a kinetic study. international journal of chemical engineering and applications, 1(3) 2010 30. akpan, u.g., and hameed b.h., parameters affecting the photocatalytic degradation of dyes using tio2-based photocatalysts: a review, j. hazard. mater., 170 (2009) 520–529 31. shiraishi y., h. hara, t. hirai, and i. komasawa, a deep desulfurization process for light oil by photosensitizer oxidation using a triplet photosensitizer and hydrogen peroxide in an oil/water two-phase liquid-liquid extraction system, ind. eng. chem. res., 1999, 38, 1589-1 595. 32. gemma e. g., enzymatic degradation of polycyclic aromatic hydrocarbons (pahs) by manganese peroxidase in reactors containing organic solvents, phd dissertation, chemical engineering department, university of santiago, spain, 2007. iraqi journal of chemical and petroleum engineering vol.15 no.4 (december 2014) 3745 issn: 1997-4884 performance evaluation of three phase spray direct contact heat exchanger najim a. jassim * and fatimah a. abdulkhaleq * mechanical engineering department, college of engineering, university of baghdad abstract the present investigation deals with experimental study of three-phase direct-contact heat exchanger, for water-freon r11 system, where water is the continuous phase (liquid) and freon r11 (liquid-gas) is the dispersed phase. the test section consisted of a cylindrical perspex column with inner diameter 8cm and 1.2m long, in which, water was to be confined. liquid freon r11 drops were injected into the hot water filled column, through a special design of distributors at the bottom of the column. the liquid freon r11 drops rose on their way up and evaporated into two-phase bubbles at atmospheric pressure. the study was devoted to express the effect of process variables such as column height, freon r11 mass flow rate and initial temperature of water on the average percentage holdup, heat transfer rate, volumetric heat transfer coefficient and effectiveness. the obtained experimental results showed that the average percentage holdup increased with increasing in the process variables. the heat transfer rate increased clearly with increasing in mass flow rate of freon r11 while it increased very little when column height and initial temperature of water increased, it increased two times when increase the mass flow rate from 1.8 to 5.4 kg/hr. the volumetric heat transfer coefficient was found to decrease with increasing in column height and initial temperature of water, while it was increased with increasing in mass flow rate of freon r11. the effectiveness was found to increase (maximum 90%) with increasing in column height and decreasing in the mass flow rate of freon r11 and initial temperature of water. a statistical analysis was performed to get general correlations for the average percentage holdup, heat transfer rate, volumetric heat transfer coefficient and effectiveness as a function of the studied parameters. keywords: direct-contact heat transfer, heat exchanger, freon r11. introduction direct contact heat transfer can occur whenever two substances at different temperatures touch each other physically. the implication is that there is no an intervening wall between the two substances. the energy transport between the two streams can take place across small thermal resistances. direct-contact heat transfer between two immiscible liquids has the advantages as follow: (a) eliminating metallic heat transfer surfaces, which are prone to corrosion and fouling. iraqi journal of chemical and petroleum engineering university of baghdad college of engineering performance evaluation of three phase spray direct contact heat exchanger 38 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net (b) relative simplicity of design, utilizes natural buoyancy to create a counter flow through a column. (c) higher heat transfer rates (relatively high performance). (d) ability to operate at relatively small temperature driving forces, (e) low capital cost, and (f) lower pressure drop. the practical applications are found in water desalination, production of electricity from low or moderate temperature heat sources in geothermal brines or solar pond power plants coupled with rankine cycle, ocean thermal energy conversion, thermal energy storage system, emergency cooling of chemical reactors, and production of steam generation for the rankine power cycle from the directcontact vaporization of water with lead-bismuth eutectic in pb-bi/ water reactor (pbwr). a solar pond power plant operated with a direct contact boiler was thermally analyzed by sonn and letan [1]. this study involved six working fluids: butane, pentane, hexane, and freon r113, r114, r12 with water. the results showed net electrical outputs of 7-9 percent of the heat inputs were obtained for the low pressure fluids, such as pentane, hexane, and r113. gravity flow of brine to boiler increased these values to 8-11 percent. battya et al. [2] dealt with experimental investigation of the direct contact evaporation of r-113 in a stagnant column of distilled water. they found the temperature difference required for the complete evaporation of the dispersed phase was depended considerably on the column height. goodwin et al. [3] studied flooding limits of a large spray column used as a three-phase direct contact heat exchanger (water/n-pentane system). they had given detailed studies of the vessel pressure effects on the flooding limit for the first time. it was found that the pressure at the flooding point varies with the inverse of the pentane flow rate at constant water flow rate and temperature. celata et al. [4] reported the results of an experimental investigation on direct contact boiling of immiscible liquids (freon 114 water system). they derived the direct contact boiling efficiency by the evaluation of the fraction of freon that did not undergo the boiling process during the transit in the test section. experiments on direct-contact heat exchange between molten metal and water for steam production were conducted by cho et al. [5]. these experiments involved the injection of water into molten lead bismuth eutectic for heat transfer measurements in 1-d geometry. the results showed the effect of temperature difference between molten metal and water on the heat transfer rate would be expected to depend on the system pressure. hanna et al. [6] investigated experimental and theoretical phenomenological study of three-phase direct-contact heat exchanger for n-pentane-water system. the n-pentane holdup percentage was found to depend mainly on the npentane volumetric flow rate and the nozzle diameter. he derived a theoretical model for the prediction of nusselt number (nuc) in term of pe. hyun et al. [7] examined the operation of a liquid-liquid type direct contact heat exchanger in harnessing the solar energy. two different kinds of working fluid were tested for their thermal characteristics that were immiscible with water. stability and thermal performance were appeared to improve when the heavier working fluid was dispersed from the top of a direct contact heat exchanger. thongwik et al. [8] studied the heat transfer characteristic during ice formation of a direct contact heat transfer between carbon dioxide and water mixture. from the experiments, it was found najim a. jassim and fatimah a. abdulkhaleq -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 39 that the effectiveness of the direct contact heat transfer between the carbon dioxide and the water was closed to 100%. experimental investigation that dealt with the phenomenological study of directcontact heat exchange for isopentane/water system was presented by zablouk et al. [9]. they found that isopentane yield a slightly higher volumetric heat transfer coefficient compared with n-pentane. nomura et al. [10] described the development and performance of a direct contact heat exchanger using erythritol (melting point: 391 k) as a phase change material (pcm) and a heat transfer oil (hto) for accelerating heat storage. they showed the latent heat can be rapidly stored under large hto flow rate and high inlet temperature in the direct contact heat exchanger. experimental work the experimental system is shown schematically in fig. 1. it consists of a test section, hot water supply system, and dispersed phase supply system. the test column consists of a cylindrical pyrex glass column of 80 mm diameter and 1m long , in which the test fluid, water is to be confined, and a cylindrical perspex-made water jacket(type julabo, model mpbrue/pu), with a working temperature range of (20 to 110) ˚c and a precision of ±0.5 ˚c. a rectangular perspex water jacket is made concentrically around the inner cylindrical column. the jacket is served as a constant temperature water bath and also contributed to minimizing the heat losses from the test column by circulating water around the test column and prevented the distortion of the images of the bubbles or drops inside the test column. the bottom cover is fitted with a teflon orifice distributor from which the dispersed phase is fed. the hot water supply system is an electrical heater. it consists of a 60 liters electrical heater, water pump and an open tank. pure water was heated in this system to the desired temperature in the range of 35-55 ˚c and pumped to the test column and circulated to the test jacket by a pump. the dispersed phase supply system is an open-loop. it consists of a dispersed fluid container, regulator valve and needle valve. a regulator valve is used to maintain a constant pressure in the range of 2 to 2.5 bar in the test column. a needle valve is used to control the rate of flow of the dispersed liquid in the range of 1.8 to 5.4 kg/hr. as the dispersed liquid phase (refrigerant r11) is injected to the test column, it is converted to vapor phase. this vapor phase is drawn from the top end of the test column. typical experiments are conducted as follows: 1. water is heated in the constant temperature heating unit to the desired temperature in the range of 35 to 55 ˚c. hot water from the constant temperature bath is circulated through the test column. when the water in the test column attains the desired temperature above the dispersed phase saturation temperature (23.7 ˚c for r11), the test column is filled with water to the desired level and the circulation is stopped. 2. the dispersed fluid is injected from bottom by teflon nozzle with a certain temperature. the pressure of this fluid is measured by gauge pressure. 3. the weight of dispersed phase container is measured before and after the test by digital balance to calculate the mass flow rate of dispersed phase with stop watch. the test is depicted by digital camera to measure the increasing in water level. performance evaluation of three phase spray direct contact heat exchanger 40 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net data analysis the experimental measurement of temperatures is an important part of this work because it illustrates the change in actual heat transfer rate and effectiveness of the heat exchanger. by assuming no heat losses from the test column, and knowing inlet and outlet temperatures of dispersed phase (freon r11), and initial and final temperature of continuous phase (water), one calculates the temperature difference, heat transfer rate, and volumetric heat transfer coefficient from the following heat balance: ̇ ( ) ̇ ( ) …(1) volumetric heat transfer coefficient is [5]: …(2) where: that's where lmtd cannot use to calculate volumetric heat transfer coefficient in stagnant column. but it must use ∆t instead of lmtd. the overall performance of the direct contact heat exchanger in the present work can be quantified by defining the heat exchanger effectiveness (e), in such a way that it gives the ratio of the actual heat gain (q) of the dispersed fluid to the maximum possible heat transfer from the continuous fluid. here, the maximum possible heat transfer refers to the case when there is no temperature difference between the two fluids in heat communication. this is only possible when the heat exchanger is infinitely long and maximum possible heat transfer can take place. the expression for the effectiveness (e) could be written as hyun [7] and thongwik [8]: …(3) the average holdup is defined as the ratio of the volume of the dispersed phase to that of the total fluid volume. if ho is the column height before the injection of the dispersed phase and h is the column height when the dispersed phase escapes as a vapor, the average holdup is given by the following equation [1] and [5]: …(4) discussion of results three variables are studied in directcontact heat exchanger: column height, initial temperature of water and dispersed phase mass flow rate for the ranges shown table 1. for this range, the distributor has 19 holes each 1 mm in diameter. figs. 1-3 show the average percentage holdup at different process variables. in general, average percentage holdup increases with increase each one of the variables. fig.1 shows the change of gas holdup with column height. average percentage holdup increases with increasing in column height of water due to increasing the bubbles growth. this is due to increasing in time contact which leads to increase in heat transfer and the size of bubbles will be increase. table 1: working range of corresponding real variables variable range column height (cm) 5 ≤ h ≤ 40 initial temperature of water (˚c) 35 ≤ tci ≤ 55 mass flow rate of freon 11 (kg/hr) 1.8 ≤ ̇ ≤ 5.4 fig. (2) illustrates the effect of mass flow rate of freon r11 on the average najim a. jassim and fatimah a. abdulkhaleq -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 41 percentage holdup. when the mass flow rate increases, the number of bubbles will be increased then the average percentage holdup increase. fig. 1: variation of ϕ versus h fig. 2: variation of ϕ versus ̇ fig. 3: variation of ϕ versus tci the influence of initial temperature of water on percentage gas holdup is shown in fig. 3. the increasing in initial temperature means increasing in the temperature difference between the continuous and dispersed phases. that leads to increase in heat transfer between the warm water and gas bubbles and increasing in the size of gas bubbles (increasing the bubbles growth). figs. 4-6 show the heat transfer rate at different process variables. fig. 4 shows the change of the heat transfer rate with column height. it increases very slightly with increasing in column height of water due to increasing in the time contact between the warm water and the dispersed gas bubbles. this increasing in time leads to increase in heat transfer. fig. 4: variation of q versus h fig. 5: variation of q versus ̇ fig. 5 illustrates the effect of mass flow rate of dispersed phase on the heat transfer rate. when the dispersed phase mass flow rate increases, the number of bubbles will be increased performance evaluation of three phase spray direct contact heat exchanger 42 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net then the surface area of contact between the water and bubbles is increased. that leads the heat transfer rate increases much. fig. 6: variation of q versus tci the influence of initial temperature of water on the heat transfer rate is shown in figs. 6. the increasing in initial temperature means increasing in the temperature difference between continues and dispersed phases. that leads to increase in heat transfer between the warm water and gas bubbles but this increasing is very little. the results shown in figs. 7-9 indicate the relation between the volumetric heat transfer coefficient with other variables. the effect of column height on the volumetric heat transfer coefficient is shown in fig. 7. the surface area of two phase bubble is increased rapidly with column height; this causes a rapid drop in the value of volumetric heat transfer coefficient which is in agreement with hanna [6] and vuong and sadhal [11]. fig. 7: variation of uv versus h the effect of dispersed phase mass flow rate on volumetric heat transfer coefficient has been demonstrated in the following fig. 8. volumetric heat transfer coefficient increases with increasing in mass flow rate of dispersed phase. this increase is attributed to the fact that in higher dispersed mass flow rate, which means higher liquid dispersed phase rate overcomes the increasing of surface area of the two phase bubbles leading to high volumetric heat transfer coefficient, this is reported by hanna [6]. fig. 8: variation of uv versus ̇ figs. 9 indicate the effect of initial temperature of water on volumetric heat transfer coefficient. volumetric heat transfer coefficient decreases with increasing initial temperature of water, due to increase in the temperature difference and that lead to increase in the growth rate of two phase bubbles as mentioned by by hanna [6]. figs. 10 show the effect of column height of water on exchanger efficiency. exchanger efficiency increases with increasing the column height due to the increase of the heat transfer rate between the warm water and bubbles with respect to the maximum heat transfer rate. najim a. jassim and fatimah a. abdulkhaleq -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 43 fig. 9: variation of uv versus tci fig. 10: variation of e versus h fig. 11: variation of e versus ̇ fig. 12: variation of e versus tci but exchanger efficiency decreases with increasing the mass flow rate of dispersed phase and initial temperature of water due to the increase of the maximum heat transfer rate, as shown in fig. 11 and fig. 12 respectively, this is reported by incropera amd dewitt [12]. correlations equations the correlation equations for the plotted experimental results are done to know the process variables effect on the average percentage holdup, heat transfer rate, volumetric heat transfer coefficient and exchanger efficiency. these equations are made by using the curve fitting method. this fitting is done by datafit program version 9. the form of these equations is: ̇ …(5) ∆t is the difference between initial temperate of water and the inlet temperature of dispersed phase ( ). where: α, β, γ and δ are tabulated in table 2. table 2: correlations factors π α β γ δ ϕ 32.34 0.03 0.034 0.037 q 144778.5 0.05 0.017 0.986 uv 2477754 -1.02 -0.935 0.854 e 0.456 -0.34 0.225 -0.128 *these equations can be used for (water-freon r11) system and for the following ranges: 5 ≤ h ≤ 40 cm, 20 ≤ ∆t ≤ 40 ˚c and 1.8 ≤ ̇ ≤ 5.4 kg/hr. conclusions from the analysis, the following conclusions are made: 1the average percentage holdup increases with increasing in the process variables and distributor geometry except with inlet performance evaluation of three phase spray direct contact heat exchanger 44 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net temperature of freon r11 it is decreased. its maximum increase is 85% when the column height increases from 5 to 40 cm. 2the heat transfer rate increase clearly two times when increase the mass flow rate of freon r11 from 1.8 to 5.4 kg/hr. 3the volumetric heat transfer coefficient is affected with change in the column height and mass flow rate of freon r11 and its maximum value will be at lower column height and higher mass flow rate. 4the effectiveness increases (maximum 90%) when the column height increase and the initial temperature of water decrease. nomenclature symbol notation cp specific heat at constant pressure j/kg.k. d the diameter of test column cm. e effectiveness (exchanger efficiency). h the height of the continuousdispersed phases (water-r11) cm. ho the height of the clear continuous phase (water) cm. hd1 enthalpy of dispersed phase (liquid) at inlet condition kj/kg. hd2 enthalpy of dispersed phase (gas) at outlet condition kj/kg. hmax enthalpy of dispersed phase (gas) at maximum temperature kj/kg. ̇ mass flow rate of dispersed phase kg/s. q heat transfer rate kw. qloss heat losses from the test column kw. t temperature ˚c. v operating column volume in the test column m 3 . greek symbols ɸ the average percentage holdup. δt temperature difference ˚c. α, β, γ and δ constants subscripts 1 inlet condition 2 outlet condition c continuous phase d dispersed phase f final condition i initial condition v volumetric references 1a. sonn and r. letan, 1981, "thermal analysis of a solar pond power plant operated with a direct contact boiler", asme, winter annual meeting, washington, dc. 2p. battya, v.r. raghavan and k.n. seetharamu, 1983, "an experimental investigation of direct contact latent heat transfer between two immiscible liquids", eighth australasian fluid mechanics conference. 3p. goodwin, m. coban and r. boehm, 1985, "evaluation of the flooding limits and heat transfer of a direct contact three phase spray column", the national heat transfer conference, the american society of mechanical engineering. 4g. p. celata, m. cumo and f. d'annibale, 1995, "direct contact evaporation of nearly saturated r 114 in water", international journal of heat and mass transfer, vol. 38, issue 8, pp. 1495-1504. 5d. h. cho, r. j. page, d. hurtault, s. abdulla, x. liu, m. h. anderson, r. bonazza and m. l. corradini, 2002, "direct contact heat exchange interfacial phenomena for liquid metal reactors: part iheat transfer", 10th international conference on nuclear engineering, arlington, va, usa. 6fadi zakariya hanna, 2003, "evaporation of n-pentane in threephase direct-contact heat exchanger", thesis chemical engineering department of university of technology. najim a. jassim and fatimah a. abdulkhaleq -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 45 7y.j. hyuna, j.h. hyuna, w.g. chuna and y.h. kang, 2005, "an experimental investigation into the operation of a direct contact heat exchanger for solar exploitation", international communications in heat and mass transfer, vol. 32, pp. 425-434. 8s. thongwik, n. vorayos, t. kiatsiriroat and a. nuntaphan, 2008, "thermal analysis of slurry ice production system using direct contact heat transfer of carbon dioxide and water mixture, international communications in heat and mass transfer, vol. 35, pp. 756-761. 9m. a. zablouk, f. z. hanna and m. hayek, 2012, "experimental investigation of direct-contact heat transfer in iso-pentane/water systems", sixth jordanian international chemical engineering conference, amman. 10takahiro nomura, masakatsu tsubota, teppei oya, noriyuki okinaka and tomohiro akiyama, 2013, "heat storage in directcontact heat exchanger with phase change material", applied thermal engineering, vol. 50, pp. 26-34. 11f. p. incropera and d. p. dewitt, 1981, "fundamentals of heat and mass transfer", john wiley and sons, new york, chap. 11, pp. 520. 12s.t. vuong and s.s. sadhal, 1989, "growth and translation of a liquid-vapour compound drop in a second liquid", j. fluid mech., vol. 209, pp. 639-660. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.22 no.1 (march 2021) 29 – 38 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name : ayat ragheb muhammad al-karbalai, email: ayaatragheb3@gmail.com , name: adel sharif hammadi, email: 80013@uotechnology.edu.iq, name: ghassan hamid abdul majeed, email: ghmajeed@gmail.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. treating wet oil in amara oil field using nanomaterial (sio2) with different types of de emulsifiers ayat ragheb muhammad al-karbalai a , adel sharif hammadi b and ghassan hamid abdul majeed c a department of petroleum technology / college of engineering / university of technology, b department of chemical engineering / college of engineering / university of technology, c research and development department / ministry of higher education and scientific research / baghdad, abstract one of the most important problems in the oil production process and when its continuous flow, is emulsified oil (w/o emulsion), which in turn causes many problems, from the production line to the extended pipelines that are then transported to the oil refining process. it was observed that the nanomaterial (sio2) supported the separation process by adding it to the emulsion sample and showed a high separation rate with the demulsifiers (rb6000) and (sebamax) where the percentage of separation was greater than (90 and 80 )% respectively, and less than that when dealing with (sodium dodecyl sulfate and diethylene glycol), the percentage of separation was (60% and 50%) respectively. the high proportion of (nacl + distilled water) raises the probability of the separation efficiency as the separation was (88.5,79)% and (65.5, 55) % for (rb6000, sebamax)respectively with (sio2) at 70 °c, while the results of separation were (77,85)% and (65,40) for (rb6000, seba max) respectively with (sio2) at 50 °c after 120 minutes, where the (w/o ratio) was (9:1) for the high separation results and (7:3) for the lower separation results, at a speed of (12000rpm), and with a salt concentration of (1500) ppm, and less of these results at lower volumetric and temporal conditions. the (nacl) salt deals with the wall films separating the droplets and reduces their viscosity [1]. as for the ph factor, it is at the value (2 and 3) represent a stable emulsion that is difficult to separate easily, but with the passage of raising the ph away from the acidic medium and near to the basic direction, a significant increase in the separation process was observed compared with the acidic medium at lower values, after 120 minutes the separation seemed to be good efficient, reaching (60 and 70) % respectively, while at the same time the emulsion reached a more efficient separation level with a ph of ( 8 and 7) equal to (80 and 87.3) %, at 50 °c with sebamax demulsifier in presence of (sio2), and with the same ph values, an increase was observed in the separation with the increase in temperature to (70 °c), then it returns to be a reverse emulsifier when the value exceeds (10) to (11, 12, 13). keywords: emulsion, demulsifiers, crude oil, saltwater, w/o emulsion, nanomaterial received on 18/08/2020, accepted on 12/12/2020, published on 30/03/2021 https://doi.org/10.31699/ijcpe.2021.1.4 1introduction in the oil production process, the formation of emulsions such as water in oil (w / o) is common due to the simultaneous continuous flow of the produced oil and water and high shear rates [2], which are mainly associated with the throttle valves, which leads to an increase in the area of the oil and water phases. in this case, inorganic colloids are accompanied by organic molecules and molecules with active interfaces (for example, asphalt and naphthenic acids) that increase the viscosity of the emulsion mechanically, resulting in a stable emulsion. this stability leads to a noticeable increase in the viscosity of the emulsion formed that can become greater than that of the oil itself, which leads to loss of system head, and thus reduces the productivity of wells and the capacity of the production system, mainly in deep waters, with a significant increase in production costs[3]. some iraqi oil fields, especially the amara field in maysan governorate (about 10 km southwest of the city of amara), suffer from the problem of wet oil (emulsion) [4]. the presence of this contamination in the oil is a big problem that leads to reducing the efficiency of the units that the oil passes through production processes [5]. the presence of salts will lead to precipitation in the heat exchanger tubes and furnaces in the form of solid blocks that reduce the diameters of these tubes and then increase the skin temperature and cause damage with them, and therefore these units are completely damaged, which leads to a large loss in production due to the suspension of these units from intentional maintenance [6]. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:ayaatragheb3@gmail.com mailto:80013@uotechnology.edu.iq mailto:ghmajeed@gmail.com http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2021.1.4 a. r. m. al-karbalai et al. / iraqi journal of chemical and petroleum engineering 22,1 (2021) 29 38 30 as a result of the presence of water in the oil and its containment of a large number of salts that are mainly available in the form of chlorides (cacl2), (mgcl), and (nacl), hydrochloric acid is formed as a result of the dissolution of calcium chloride during the distillation process, and this acid has a great corrosive effect, which causes corrosion of units and equipment. [7]. emulsions also cause an increase in energy consumption because the presence of water in the crude oil leads to an increase in energy consumption[8], all of these problems reduce the economic oil factor in the iraqi market and the factor of the low quality of these heavy oils, according to (a. saniere et al.,2004), options include improving quality to produce marketable crude oil, including carbon subtraction processes such as carbonization or hydrogen addition processes, the dilution process is one of the methods for improving heavy oils and the least costly, as higher quality oil is used to produce a product that can be further improved in another way[9]. the results showed that the (nano-sio2) should interact with asphalt and resin surfaces and reduce the stability of the membranes surrounding the emulsion droplets as the addition of nanomaterial accelerates the process of breaking the inner interfacial film and isolates water droplets faster and in the shortest time possible [10]. while (d.m. pinchao, and et al) found that the optimum separation efficiency (92%) was achieved at a concentration of 1000 ppm sio2 nanoparticles and (5:5 ratio), an increase of 15% compared to the amount of water separated using only the de-emulsifying agent. on the other hand, the concentrations of 4000ppm and 10,000ppm of sio2 nanoparticles reached much lower amounts than the water separation, 4%, respectively, due to the over-saturation in the mixture. [11]. in this research, water surfactants (that can be mixed with water) will be dealt with to tear the water droplet membrane and sediment it away from the oil drop, solid nanomaterials (powder) will be used where the action of the solid particles is to break the elastic membranes and thus drops coalesce with some of them and separated from the oil. 2experimental work 2.1. work method the method of work that was relied upon is (bottle testing), which includes adding crude oil samples after mixing it with a homogeneous mixer device for a period of (6 minutes) to a group of glass cylinders containing gradients per volume unit (milliliter) after which the demulsifier is added and the bottle shaken for (3 minutes) and then these samples are placed in a water bath with different temperatures (15, 50, 70, 100) c° for two hours, then reading the level of separation of water from oil and recording these readings within the time (120 minutes). 2.2. explanatory work tables table 1. brief the ratios and sizes adopted in the process of separating water from oil ph value mixing speed(rpm) nacl (ppm) temperature c° sedimentation time (min) nanomaterials concentration (ppm) dose injection (ppm) 2 3 4 5 6 7 8 9 10 11 12 6000 10000 12000 250 500 750 1000 1250 1500 1750 15 50 70 100 20 30 60 120 300 600 900 1200 1500 1800 2100 2400 2700 3000 500 1000 1500 2000 2500 3000 3500 table 2. crude oil test results (amara field) before treatment (al-dora refinery) result test 23.1 api gravity at 15.6 c 0.9153 sp.gravity at 15.6 c 0.9148 density at 15c 3.67 sulfur content % wt. 34.1 kin.viscosity cst. at 37.8c 0.7800 salt content% wt. 7139.34 salt content ppm 11.6 kuop characterization factor 7.0 water content vol.% a. r. m. al-karbalai et al. / iraqi journal of chemical and petroleum engineering 22,1 (2021) 29 38 31 3the properties of the demulsifies used& nanomaterial 3.1. the properties of the demulsifies table 3. characteristics of the demulsifies are used flash point c pour point viscosity 20 c° (cp) sp. gr at 20c° m.w. gm/mol density gm/ml hlb no. descript ion type of demulsifiers name of demulsifies 170 °c / / no info-rmation 288.372 1.01 40 white powder an ionic sodium dodecyl sulfate(sds) 154 °c -11 14.0 cs 1.12 106.12 1.118 6.0 colorles s liquid nonionic diethylene glycol (deg) 70 c < <-30 c <50 0.94 / / / brown liquid (ionic)an rb6000 / / / / no further relevant information / / brown liquid (ionic)an sebamax 3.2. the properties of the nanomaterial table 4 characteristics of the sio2 nanomaterial used surface activity color and appearance purity % densit g/cm3 mwt(g/mol) particle size(nm) ph nanomaterial negative charged white powder 99.5+ 2.643 60.08 15-20 3.7 sio2 (silicon oxide) 4experimental procedure to know the stability of emulsions in the amara oil field, it is necessary to note the figure below showing the amount of water droplets dispersed in one drop of oil, thus knowing exactly how to process and the amount of materials to be added during the test. fig. 1. a real picture for a drop of emulsified oil that is highly stable from the amara field under an electron microscope (ministry of science and technology environment and water laboratory) at the beginning of the work, the brine solution is prepared after adding different proportions of ( nacl salt) with the emulsified oil and the mixing time is for (6 minutes) at different speeds (12,000,6000,10000 rpm) and then the nanomaterial is added (sio2) at different concentrations each time the treatment process is repeated and mix it with the previous solution for (5 minutes) on (hotplate stirrer), then put the homogeneous solutions after mixing in the test bottle and add demulsifier and close the bottle, then shake it for (3 minutes) by hand, after that it is placed in the water bath at a reservoir temperature of 70 ° c, as shown in fig. 2. the samples are prepared as follows (oil emulsion with (saltwater) and demulsifiers/nanoparticle):-four different aqueous solutions were prepared (first mixture: 100g water, 1 wt. % nacl, and 1 wt. % sds, and 1 wt. % sio2 ), (second mixture: 100g water, 1 wt. % nacl, and 1 wt. % diethylene glycol, and 1 wt. % sio2), (third mixture: 100g water, 1 wt. % nacl, and 1 wt. % rb6000, and 1 wt. % sio2), (fourth mixture:100g water,1wt.% nacl, and 1 wt.% sebamax, and 1 wt. % sio2), the percentages of water added to the oil were as shown in the table (5). these models are re-equipped with the rest of the demulsifier types, temperatures, and speeds to observe and record the difference in the treatment process and separate the water from the oil. a. r. m. al-karbalai et al. / iraqi journal of chemical and petroleum engineering 22,1 (2021) 29 38 32 table 5. (water to oil ratio ) amarah crude oil was added to the aqueous solutions in the bottle test water to oil ratio 1:9 5:5 7:3 9:1 fig. 2. place test bottle samples in the water bath 5results and discussion sample (a) sample (b) sample (c) fig. 3. three samples of (w/o) emulsion after treatment over time (30min) (by adding different types of demulsifiers ) with concentration (500 ppm) for demulsifies and a temperature of (50 ° c) with mixing speed (10000 rpm) with (w/o) ratio is(1:9) from left to right (with demulsifiers) 1the results of the treatment for sample (a) with the demulsifiers type (sds) showed good separation within a short time when the separation ratio reached (10ml) 2the results of the treatment for sample (b) with the demulsifiers type (deg) showed slightly separation within the same time when the separation ratio reached (6ml) 3the results of treating the sample (c) with the type of demulsifiers (rb6000) showed a significant separation during the same time in which the level of separation was (15 ml). sample (a) sample (b) sample (c) fig. 4. three samples of (w/o) emulsion after treatment and a demulsifies (seba max) at the concentration (500 ppm), and a temperature of (15 ° c) and (5:5 w/o ratio) from right to left 1-a sample (c) showed the result of separation at a level of (2ml) after the passage of (20 min) time and at a mixing speed of (10000 rpm) without adding (sio2). 2-a sample (b) showed a separation result at a level of (5ml) after the passage of (30 min) time and at a mixing speed of (10000 rpm) without adding (sio2). 3-a sample (a) showed a better separation result than previous samples with a separation level (17ml) after a (30 min) time and at a lower mixing speed of (6000 rpm) in the presence of the nanomaterial (sio2=300 ppm). 5.1. temperature effect in fig. 5, the increase in the separation process is proportional to the increase in temperature over time, and the highest level of separation is at a temperature of (70)°c and after (120 minutes). the figure also shows that the wet oil was treated with a demulsifier (sibamax) with a concentration of (500 ppm), where we notice that the separation rate started at (30)% at the temperature (15)°c and the separation began to increase upward with the rise in temperature to (70)°c which equal to (85%), but when the temperature increased to the maximum at (100 °c), the emulsified oil starts the intensity and stability increases, and transforming into a reverse emulsion, after (120 minutes). a. r. m. al-karbalai et al. / iraqi journal of chemical and petroleum engineering 22,1 (2021) 29 38 33 it is observed that the heat in the process of separating the water from the oil has a basic effect; as it helps to reduce the viscosity of the oil, and the effect of heat in reducing viscosity helps to increase the separation speed by enhancing the fusion of the drops that will form large drops as a result of a collision with each other [12], despite the positive effects of heat on the entire process, there is some negative impact on oil containing light compounds, their evaporation may affect the total volume of oil, as approximately 1% of the total volume is lost, and also the release of these compounds or gases may cause a disruption that hinders the gathering water droplets and prevents their stability, and this problem is addressed by taking into account the design of the buffer in the field; in new designs, oil is kept above the bubble pressure by placing small insulators above the treatment vessels [13]. fig. 5. the effect of different temperatures on (water –oil) separation at (500ppm) sebamax, (10000rpm), (1:9 w/o ratio),nacl concentration(250ppm), at different temperature (15,50,70,100) °c 5.2. ph effect the ph of water has a strong influence on its emulsion stability (water/oil), the stable hard emulsion film contains organic acids and bases, asphalt, and solids with ionizing groups. the addition of inorganic acids and bases strongly influences their ionization in the interlayers and radically changes the physical properties of the films [14]. the ph of water affects the hardness of the interlayer membranes that need to be fused and precipitate into the bottom for the separation to succeed [15]. in fig. 6, in which the effect of the ph on the process of separating water from oil and in brine is shown as the ph (2 and 3) represent a stable emulsion that is difficult to separate easily, but with the passage of raising the ph away from the acidic medium and close to the basic direction, we notice the beginning of the separation process significantly compared to the acidic medium and the reason for this difference is due to the separation with the difference in the ph to the attractive forces and the repulsion provided by the salt medium by the presence of an (ionic demulsifiers), where the concentration of the brine solution increases as the ph rises [16]. the other reason for the high separation ratio whenever we exceed the ph value (7 and 8) to the imbalance of the stability of the emulsion and its disorder due to the loss of the surface tension force of the droplets heading towards coalescence, and the formation of larger drops, which leads to their sedimentation at the bottom and their separation from the oil droplets, and as a result of the difference in densities, the oil is up and the water settles down, which means a successful separation process and after 120 minutes have passed, but when the ph value increases more than necessary, we notice that a reverse emulsion is formed, and the separation value returns by dropping to a level lower at (ph = 11 and 12).[17] the amount of ph is variable from distilled water to brine; this difference is due to the effect of ionization (ionic bonding/reaction in brine with asphalt). for most brine systems, there is an ideal ph level at which the membrane surrounding the droplets will exhibit minimal emulsion stability or maximum emulsion fracturing properties, and the ph value (optimal value) depends on two important factors (properties of the crude oil and brine composition). the last factor appears to be the most important. [18] fig. 6. effect of ph on separation process at 50 c° with sebamax at (1500 ppm) in the presence (sio2=900 ppm),(1200 rpm), nacl concentration (750 ppm) 5.3. effect of injected dose of demulsifiers also, an important factor affecting the emulsion separation process is the amount or dose of demulsifiers added to the emulsified oil mixture. the amount of the added dose affects the success or failure of the separation process, as the large amount is harmful in the treatment process (excessive treatment state) which may cause an emulsion reverse, while very low doses may lead to treatment failure due to insufficient dose breakage and penetration of the membranes of the drops of saltwater in the emulsified oil. in fig. 7, the concentrations of the demulsifier (rb6000) ranged from (500ppm) to (2500ppm), where the separation ratio was at the lowest level at the concentration (500 ppm) was (29.7%), while the increase in the separation with the increase in the values of the demulsifier concentrations and reached the highest separation rate it is (75%) at the concentration (2500 ppm). a. r. m. al-karbalai et al. / iraqi journal of chemical and petroleum engineering 22,1 (2021) 29 38 34 fig. 7. effect of injected dose of demulsifier (rb6000) at (50°c),10000 rpm, (water/oil ratio= 7:3), at sio2 concentration (1800ppm),nacl concentration (1000ppm) 5.4. effect of demulsifies types in fig. 8 an illustration of the best separation when using a different group of demulsifiers where the separation ratio increases with (rb6000) and is slightly less than it with the use of the enhanced demulsifiers (sebamax) and less than with (sds) after the nanomaterial is mixed (sio2) with emulsion, the separation ratio increased and the treatment of wet oil was improved. this is due to the ionic surfaces of the demulsifiers, which can attract water droplets after penetration by the solid nanomaterial and thus collect and deposit them as a result of gravity and increase the weight of the droplet, so it is pushed back to the bottom of the bottle test is away from oil droplets and due to different densities, which requires oil to rise and water down. in the case of the (deg) demulsifiers with a positive (non-ionic) surface, its separation ratio is low compared to the rest of the aforementioned fractions, and it takes a longer time for the treatment result to appear. and for the demulsifier to be effective, it must be mixed well with the emulsion for the molecules of the active chemical to surface to penetrate the flexible membranes surrounding the saline water system drops. if the mixing process is insufficient and slow, then the treatment is futile. the emulsifier breaker should be injected into the crude oil (the continuous phase in the emulsified mixture) typically through (homogeneous mixer at a variable and suitable speed) to form a one-way stream that is sufficient to mix the refractory with the emulsion taking into account the time sufficient for complete mixing [19]. the difference in the separation efficiency of each type of demulsifies is due to the different molecular weights of the polymeric compounds involved in the structure of each type, and consequently the difference in the interaction efficiency with the surfaces of the membranes surrounding the emulsion drop and the reduction of the surface tensile strength as the commercial demulsifiers are more feasible and effective than the local demulsifiers manufactured for treatment purposes with less stable emulsions. the higher of molecular weight of the demulsifiers, the greater the separation efficiency. (rb6000 is the highest molecular weight) despite the lack of information on (rb6000 and sebamax). fig. 8. effect of demulsifies types with (sio2) at (2100 ppm) concentration of (sio2) with (2000ppm of demulsifiers) after (2hr),(7:3 water-oil ratio), (250 ppm nacl) with mixing speed at (12000rpm) in (70°c ). 5.5. effect of mixing speed speed is an important factor in the wet oil treatment process. increasing the mixing speed results in a more homogeneous mixture, thus increasing the collision of the mixture particles with the demulsifiers helps to separate faster. speed is also one of the factors that affect the temperature and increase the pressure on the membranes, as the high speed means the increase in the movement for emulsion droplets, that lead to a decrease in viscosity, so at the speed (12000 rpm) the separation process is faster and greater than the lowest speed (10,000 & 6000 rpm), but when the mixing is increased more than the required limit, we notice that the emulsified oil returns to a reverse emulsion at the speed (13000 rpm) as showing in fig. 9. fig. 9. effect of mixing speed in wet oil separation a. r. m. al-karbalai et al. / iraqi journal of chemical and petroleum engineering 22,1 (2021) 29 38 35 5.6. nanomaterial concentration effect nanoparticles are the best suggestion when treating hydrocarbons (separating saltwater from oil), and studies have shown that nanoparticle such as (sio2) can remove oil drops from the emulsion faster compared to conventional separations this is due to the ability of the solid nanomaterial surfaces of a substance (sio2) to penetrate the water droplet and tear the interstitial membrane that prevents the drops from coalescing and separating them from the oil. therefore, the solid nanomaterial possesses a high ability to reduce surface tension. it was observed that when using nanoparticles of (sio2) the separation process with the presence of demulsifies (rb6000, seba max) is much larger in the test bottle after (40 min) and (120 min), which is the case when separating without nanomaterial, (as shown in fig. 10. in the image in fig. 10, an emulsion (water/oil) before and after injection of the nanomaterial (sio2) where the nanomaterial contributed to tearing the membranes surrounding the water droplet, accumulating it and collecting it, thus depositing it on the bottom away from the oil drop, which made the emulsion less stable fig. 10. optical microscope photos of the w / o emulsion(a) 10 minutes, (b) after 40 minutes, (c) after injecting the nanomaterial, and collecting water droplets. in fig. 11, we notice that the greater concentration of the nanomaterial added to the emulsion sample resulting greater the separation process over time, at the lowest concentration of nanomaterial which is (300 ppm) the separation ratio was lowest and equal to (20%), while the separation percentage reached the highest (88%) at the concentration (2700 ppm) after 120 minutes, while when the concentration increased above the permissible limit to ( 3000 ppm), the wet oil returns a reverse emulsifier. fig. 11. nanomaterial concentration effect 5.7. salinity effect the salt concentration added to the emulsified oil has a major effect on the membrane droplet of saltwater in crude oil. the crude oil extracted from the reservoir is usually accompanied by water droplets in the form of a highly stable emulsion [20] . this salty water present in the oil contains asphalt, waxy materials, and other impurities, which are one of the factors that stabilize the emulsion. asphalt plays a major role in forming the film or the interlayer that increases the repulsion forces between the water droplets [21], so comes the role of (nacl) in tearing these membranes surrounded by water droplets and releasing them from repulsive forces to attract and integrate them and thus sediment them at the bottom of the test bottle and calculate the separation ratios, it has been observed that the higher tds factor increases the separation.[22] in other words, the results (bottle test) showed that the optimal concentration of the nano emulsification fraction increased its efficiency when increasing the concentration of salt (nacl), as the (distribution of the size of the droplet dsd) increased as a result of adding salt and this increase is accompanied by a decrease in the emulsion viscosity, which leads to reduced emulsion stability [23]. also, this increase is accompanied by an increase in the spread of small droplets and their precipitation over the larger droplets, thus increasing the drop's weight and fusion, which means its deposition at the bottom, which in turn increases the efficiency of the nanomaterials added to break the stable emulsion as in fig. 12. fig. 12. the effect of salinity ( from 250 to 1750 ppm) of nacl ) after 120 min at (2000 ppm concentration of sebamax demulsifier) at 70 c° and (1000rpm) with (5:5 water-oil ratio), with a fixed concentration of nanomaterial (sio2) equal (1800ppm) 5.8. effect of surfactant here it must be noted that the treatment method in the amara oil field is limited to the use of commercial demulsifiers (rb6000 & sebamax) without any chemical additives that support the separation and treatment process. a. r. m. al-karbalai et al. / iraqi journal of chemical and petroleum engineering 22,1 (2021) 29 38 36 in this paper, it had been focused on studying the effect of adding nanomaterial (sio2) and its support for demulsifiers in the wet oil treatment process, where it was observed that the relationship between surface stimuli (ionic –sio2) and demulsifiers is linear (23), which means that if we increase the surfactant twice, this corresponds to a doubling increase in the amount of demulsifiers needed to break down the emulsion, as shown in fig. 13 fig. 13. effect of surfactant (sio2) on demulsifier performance 6conclusions the asphaltic functional groups become charged, which enhances the repulsion of the droplets and increases the elasticity of the interlayer, and the surface tension increases, and here comes the role of factors (ph and nacl) in changing the charge of ions surrounding the water droplet membrane, so the electrostatic stability decreases, which helps the water droplets merge, which is a stage (coalescence ( heat and mixing speed have a major effect on reducing the viscosity of the oil and thus ease of processing and breaking emulsification, and the separation efficiency increases if the (sio2) nanomaterial is added with the emulsification breaker (rb600 and sebamax) and less than that with (sds and deg) as in fig. 8 the separation process is stabilized after two hours under precise laboratory conditions. all conditions and parameters, whether very few or very large, affect the wet oil treatment process (emulsion), as the emulsion is transformed into another type which is an emulsion (oil / in water). abbreviations acronym description bs&w basic sediment and water c° degree centigrade dsd droplet size distribution deg diethylene glycol mwt molecular weight ml milliliter ppm parts per million rpm rotation per minute nacl sodium chloride sio2 silicon dioxide v/v % (volume/volume) percentage w/o water-in-oil emulsion wt. % weight percentage references [1] a. al-alawy and m. al-ameri, “treatment of simulated oily wastewater by ultrafiltration and nanofiltration processes”, ijcpe, vol. 18, no. 1, pp. 71-85, mar. 2017. [2] ajay mandal, achinta bera, "modeling of flow of oil-in-water emulsions through porous media", journal of petroleum science and technology,vol.12no2(april 2015) [3] troner a.de souzaa , agnes de p.scheera , márciacristina khalilb, carlos i. yamamotoa, luiz fernando de l.luzjr.a , "emulsion inversion using solid particles" , journal of petroleum science and engineering ,v. 96–97, october 2012. pages 49-57 [4] kadhem hammoud manati ; (report about amara gas separation plant), maysan oil company (moc), operations authority (production and discharge authority), petroleum engineering department (2018). [5] bhardwaj, a. and hartland, s, "studies on build up of interfacial film at the crude oil/water interface", journal of dispersion science and technology, vol 19. no.4,pages 465-473, (1998). [6] selvarajan radhakrisnan, anantha-subramaniam sivakumar , robert a. m, " aqueous dispersion of an oil soluble demulsifier for breaking crude oil emulsions", us patent , no.6, pages 294,093,(2001). [7] swastic and das, s. ,"effect of different acids on the scale in pipelines of linz-donawitz (ld) plant (steel making process)" ,. advances in chemical engineering and science,no5, pages 192-196, (2015). [8] siew fan wong,j.s.lim , sharul sham dol," crude oil emulsion: a review on formation, classification and stability of water-in-oil emulsions", journal of petroleum science and engineering vol.135,nov.2015,pp 498-504. [9] a. saniere, i. hénaut, j.f. argillier," pipeline transportation of heavy oils a strategic, economic and technological challenge", oil & gas science and technology rev. ifp, vol. 59no.5 (2004), pp. 455-466 [10] f. h. wang, l. b. shen, h. zhu, k. f. han, " the preparation of a polyether demulsifier modified by nano-sio2 and the effect on asphaltenes and resins", petroleum science and technology, vol.29no24, (25-oct,2011), pp2521-2529 [11] d. m. pinchao, c. a. cedeño, f. b. cortés, c. a. franco, "water/oil emulsions separation using sio2 nanoparticles/surfactant-based nanofluids" , universidad nacional de colombia , acipet journal, 2015. [12] hemmingston, p.v., silset, a., hannisdal, a., sjöblom, j; " emulsions of heavy crude oils i: influence of viscosity, temperature and dilution"; . j. disp. sci. technol. 2005. 26, 615–627. https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/194 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/194 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/194 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/194 https://link.springer.com/content/pdf/10.1007/s12182-015-0025-x.pdf https://link.springer.com/content/pdf/10.1007/s12182-015-0025-x.pdf https://link.springer.com/content/pdf/10.1007/s12182-015-0025-x.pdf https://link.springer.com/content/pdf/10.1007/s12182-015-0025-x.pdf https://www.sciencedirect.com/science/article/abs/pii/s0920410512001969 https://www.sciencedirect.com/science/article/abs/pii/s0920410512001969 https://www.sciencedirect.com/science/article/abs/pii/s0920410512001969 https://www.sciencedirect.com/science/article/abs/pii/s0920410512001969 https://www.sciencedirect.com/science/article/abs/pii/s0920410512001969 https://www.tandfonline.com/doi/abs/10.1080/01932699808913189 https://www.tandfonline.com/doi/abs/10.1080/01932699808913189 https://www.tandfonline.com/doi/abs/10.1080/01932699808913189 https://www.tandfonline.com/doi/abs/10.1080/01932699808913189 https://patents.google.com/patent/us6294093b1/en https://patents.google.com/patent/us6294093b1/en https://patents.google.com/patent/us6294093b1/en https://patents.google.com/patent/us6294093b1/en https://patents.google.com/patent/us6294093b1/en https://www.scirp.org/html/10-3700531_55507.htm https://www.scirp.org/html/10-3700531_55507.htm https://www.scirp.org/html/10-3700531_55507.htm https://www.scirp.org/html/10-3700531_55507.htm https://www.scirp.org/html/10-3700531_55507.htm https://www.sciencedirect.com/science/article/abs/pii/s0920410515301315 https://www.sciencedirect.com/science/article/abs/pii/s0920410515301315 https://www.sciencedirect.com/science/article/abs/pii/s0920410515301315 https://www.sciencedirect.com/science/article/abs/pii/s0920410515301315 https://www.sciencedirect.com/science/article/abs/pii/s0920410515301315 https://ogst.ifpenergiesnouvelles.fr/articles/ogst/abs/2004/05/saniere_vol59n5 https://ogst.ifpenergiesnouvelles.fr/articles/ogst/abs/2004/05/saniere_vol59n5 https://ogst.ifpenergiesnouvelles.fr/articles/ogst/abs/2004/05/saniere_vol59n5 https://ogst.ifpenergiesnouvelles.fr/articles/ogst/abs/2004/05/saniere_vol59n5 https://ogst.ifpenergiesnouvelles.fr/articles/ogst/abs/2004/05/saniere_vol59n5 https://www.tandfonline.com/doi/abs/10.1080/10916460903393997 https://www.tandfonline.com/doi/abs/10.1080/10916460903393997 https://www.tandfonline.com/doi/abs/10.1080/10916460903393997 https://www.tandfonline.com/doi/abs/10.1080/10916460903393997 https://www.tandfonline.com/doi/abs/10.1080/10916460903393997 https://www.tandfonline.com/doi/abs/10.1081/dis-200057671 https://www.tandfonline.com/doi/abs/10.1081/dis-200057671 https://www.tandfonline.com/doi/abs/10.1081/dis-200057671 https://www.tandfonline.com/doi/abs/10.1081/dis-200057671 a. r. m. al-karbalai et al. / iraqi journal of chemical and petroleum engineering 22,1 (2021) 29 38 37 [13] jones, t.j., neustadter, e.l., and wittingham, k.p., “water-in-crude oil emulsion stability and emulsion destabilization by chemical demulsifiers”, j. petrol .can. technol., pp 100-108, april-june (1978). [14] sunil lalchand kokal, 'crude oil emulsions: a state-of-the-art review' ; spe journal, vol.20, 2005. [15] kokal, s.l. and sayegh, s.g., “asphaltenes: the cholesterol of petroleum”, spe journal, march ( 1995). [16] j.e. strassner, "effect of ph on interfacial films and stability of crude oil-water emulsions ", journal of petroleum technology, society of petroleum engineer,v.20,pp 308-309, march 1968. [17] strassner, j.e., "effect of ph on interfacial films and stability of crude oil-water emulsions", j. petrol. technol, march (1968) , pp 303-312 [18] salager, j.l., "the fundamental basis for the action of a chemical dehydrant: influence of physical and chemical formulation on the stability of an emulsion" ,int. chem. eng., vol 30no1, pages 103116 (1990). [19] a.m.alsabagha,m.e.hassanb , s.e.m.desoukya, n.m.nassera , e.a.elsharakya, m.m.abdelhamid, " demulsification of w/o emulsion at petroleum field and reservoir conditions using some demulsifiers based on polyethylene and propylene oxides" , egyptian journal of petroleum, volume 25,no.4, pages 585-595, december 2016 . [20] j.g. delgado-linares, j.c. pereira , m.rondón, j. bullón, j.-l. salager , " breaking of water-in-crude oil emulsions. estimating the demulsifier performance at optimum formulation from both the required dose and the attained instability"; energy fuels, vol.30 no6 ,pages 5483-5491,(2016). [21] j. czarnecki, p. tchoukov, t. dabros ; "possible role of asphaltenes in the stabilization of water-incrude oil emulsions" ; energy fuels, vol.26 (2012), pp. 5782-5786. [22] paul m. mcelfresh , david lee holcomb , daniel ector , "application of nanofluid technology to improve recovery in oil and gas", society of petroleum engineers, (june 2012). [23] m. fortuny, c.b.z. oliveira, r.l.f.v. melo, m. nele, r.c.c. coutinho, a.f. santos, "effect of salinity, temperature, water content, and ph on the microwave demulsification of crude oil emulsions" , energy fuels,vol. 21 ,pages 1358-1364,(2007). https://onepetro.org/jcpt/article-abstract/doi/10.2118/78-02-08/31046/water-in-crude-oil-emulsion-stability-and-emulsion?redirectedfrom=fulltext https://onepetro.org/jcpt/article-abstract/doi/10.2118/78-02-08/31046/water-in-crude-oil-emulsion-stability-and-emulsion?redirectedfrom=fulltext https://onepetro.org/jcpt/article-abstract/doi/10.2118/78-02-08/31046/water-in-crude-oil-emulsion-stability-and-emulsion?redirectedfrom=fulltext https://onepetro.org/jcpt/article-abstract/doi/10.2118/78-02-08/31046/water-in-crude-oil-emulsion-stability-and-emulsion?redirectedfrom=fulltext https://onepetro.org/jcpt/article-abstract/doi/10.2118/78-02-08/31046/water-in-crude-oil-emulsion-stability-and-emulsion?redirectedfrom=fulltext https://onepetro.org/po/article-abstract/20/01/5/112495 https://onepetro.org/po/article-abstract/20/01/5/112495 https://onepetro.org/po/article-abstract/20/01/5/112495 https://onepetro.org/spemeos/proceedings-abstract/95meos/all-95meos/spe-29787-ms/57277 https://onepetro.org/spemeos/proceedings-abstract/95meos/all-95meos/spe-29787-ms/57277 https://onepetro.org/spemeos/proceedings-abstract/95meos/all-95meos/spe-29787-ms/57277 https://onepetro.org/jpt/article/20/03/303/163776/effect-of-ph-on-interfacial-films-and-stability-of https://onepetro.org/jpt/article/20/03/303/163776/effect-of-ph-on-interfacial-films-and-stability-of https://onepetro.org/jpt/article/20/03/303/163776/effect-of-ph-on-interfacial-films-and-stability-of https://onepetro.org/jpt/article/20/03/303/163776/effect-of-ph-on-interfacial-films-and-stability-of https://onepetro.org/jpt/article/20/03/303/163776/effect-of-ph-on-interfacial-films-and-stability-of https://onepetro.org/jpt/article/20/03/303/163776/effect-of-ph-on-interfacial-films-and-stability-of https://onepetro.org/jpt/article/20/03/303/163776/effect-of-ph-on-interfacial-films-and-stability-of http://www.firp.ula.ve/cv_profesores/cv_salager/90_iche_salager.pdf http://www.firp.ula.ve/cv_profesores/cv_salager/90_iche_salager.pdf http://www.firp.ula.ve/cv_profesores/cv_salager/90_iche_salager.pdf http://www.firp.ula.ve/cv_profesores/cv_salager/90_iche_salager.pdf http://www.firp.ula.ve/cv_profesores/cv_salager/90_iche_salager.pdf https://www.sciencedirect.com/science/article/pii/s1110062116300010 https://www.sciencedirect.com/science/article/pii/s1110062116300010 https://www.sciencedirect.com/science/article/pii/s1110062116300010 https://www.sciencedirect.com/science/article/pii/s1110062116300010 https://www.sciencedirect.com/science/article/pii/s1110062116300010 https://www.sciencedirect.com/science/article/pii/s1110062116300010 https://www.sciencedirect.com/science/article/pii/s1110062116300010 https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.6b00666 https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.6b00666 https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.6b00666 https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.6b00666 https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.6b00666 https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.6b00666 https://pubs.acs.org/doi/abs/10.1021/ef300904a https://pubs.acs.org/doi/abs/10.1021/ef300904a https://pubs.acs.org/doi/abs/10.1021/ef300904a https://pubs.acs.org/doi/abs/10.1021/ef300904a https://onepetro.org/speionc/proceedings-abstract/12ionc/all-12ionc/spe-154827-ms/158129 https://onepetro.org/speionc/proceedings-abstract/12ionc/all-12ionc/spe-154827-ms/158129 https://onepetro.org/speionc/proceedings-abstract/12ionc/all-12ionc/spe-154827-ms/158129 https://onepetro.org/speionc/proceedings-abstract/12ionc/all-12ionc/spe-154827-ms/158129 https://pubs.acs.org/doi/abs/10.1021/ef0603885 https://pubs.acs.org/doi/abs/10.1021/ef0603885 https://pubs.acs.org/doi/abs/10.1021/ef0603885 https://pubs.acs.org/doi/abs/10.1021/ef0603885 https://pubs.acs.org/doi/abs/10.1021/ef0603885 a. r. m. al-karbalai et al. / iraqi journal of chemical and petroleum engineering 22,1 (2021) 29 38 38 ( مع انواع sio2معالجة النفط الرطب في حقل العمارة النفطي باستخدام المادة النانوية) من كواسر االستحالب غسان حميد عبدالمجيد3و عادل شريف حمادي2آيات راغب الكربالئي, 1 قسم تكنولوجيا النفط / كلية الهندسة / الجامعة التكنولوجية 1 قسم الهندسة الكيميائية / كلية الهندسة / الجامعة التكنولوجية 2 م العالي والبحث العلمي / بغداددائرة البحث والتطوير / وزارة التعلي 3 الخالصة تدفقه هو النفط المستحلب )الماء في النفط( والذي بدوره من أهم المشاكل في عملية إنتاج النفط وعند استمرار يسبب العديد من المشاكل ، من خط اإلنتاج إلى األنابيب الممتدة التي يتم نقلها بعد ذلك إلى مصفى النفط ( تدعم عملية الفصل بإضافتها إلى عينة المستحلب وأظهرت ارتفاًع sio2و لوحظ أن المادة النانوية ) للمعالجة. و 90( حيث كانت نسبة الفصل أكبر من )sebamax( و )rb6000دل الفصل مع كواسر االستحالب )مع sodium dodecyl sulfate and di ethylene (٪ على التوالي ، وأقل من ذلك عند التعامل مع )80 glycol ( كانت النسبة المئوية للفصل ، )ن )ترفع النسب العالية م ٪( على التوالي.50٪ و 60nacl الماء + ، rb6000(٪ لـ )55، 65.5(٪ و )88.5,79المقطر( من احتمال كفاءة الفصل حيث كان الفصل ) sebamax( على التوالي مع )sio2 ( لـ 65،40(٪ و )77،85درجة مئوية ، بينما كانت نتائج الفصل ) 70( عند (rb6000 ،seba max( على التوالي مع )sio2 عند )دقيقة ، حيث كانت )نسبة 120درجة مئوية بعد 50 دورة في الدقيقة( 12000( لنتائج الفصل األقل بسرعة )3: 7( لنتائج الفصل المرتفعة و )1: 9الماء / الى النفط( ) يتعامل ملح ( جزء في المليون وأقل من هذه النتائج في الظروف الحجمية والزمنية المنخفضة.1500وبتركيز ملح ) أما بالنسبة لعامل األس الهيدروجيني ، يد الصوديوم مع أغشية الجدار الذي يفصل القطرات ويقلل من لزوجتها.كلور ( يمثل مستحلًبا ثابًتا يصعب فصله بسهولة ، ولكن مع مرور ارتفاع الرقم الهيدروجيني بعيًدا 3و 2فهو عند القيمة ) ن زيادة واضحة في عملية الفصل لوحظت مقارنة مع الوسط عن الوسط الحمضي وقريًبا من االتجاه القاعدي ، فإ ( ٪ على التوالي ، بينما 70و 60دقيقة بدا الفصل جيد الكفاءة ، حيث وصل إلى ) 120الحمضي بقيم أقل ، بعد و 80( يساوي )7و 8يني )وصل المستحلب في نفس الوقت إلى مستوى فصل أكثر كفاءة مع الرقم الهيدروج وبنفس قيم األس الهيدروجيني ، (،sio2بوجود ) sebamaxدرجة مئوية مع كاسر استحالب 50، عند ( 87.3٪ .درجة مئوية( 70لوحظ زيادة في الفصل مع زيادة درجة الحرارة إلى ) : مستحلب, كاسر استحالب, نفط خام , مستحلب )الماء/في النفط(, مادة نانوية, ماء مالحالدالة الكلمات iraqi journal of chemical and petroleum engineering vol.14 no.1 (march 2013) 113 issn: 1997-4884 preparation and formation of zeolite 5a from local kaolin clay for drying and desuphurization of liquefied petroleum gas abdul-halim a. mohammed a and zeinab k. nassrullah b a chemical engineering department-college of engineering-university of baghdad-iraq b the state company of geological survey and mining abstract this work deals with preparation of zeolite 5a from dewekhala kaolin clay in alanbar region for drying and desulphurization of liquefied petroleum gas. the preparation of zeolite 5a includes treating kaolin clay with dilute hydrochloric acid 1n, treating metakaolin with naoh solution to prepare 4a zeolite, ion exchange, and formation. for preparation of zeolite 4a, metakaolin treated at different temperatures (40, 60, 80, 90, and 100 °c) with different concentrations of sodium hydroxide solution (1, 2, 3, and 4 n) for 2 hours. the zeolite samples give the best relative crystallinity of zeolite prepared at 80 °c with naoh concentration 3n (199%), and at 90 and 100°c with naoh concentration solution 2n (184% and 189%, respectively). zeolite 5a was prepared by ion exchange of zeolite 4a prepared at 90°c and 2n naoh concentration with 1.5 n calcium chloride solution at 90 °c and 5 hours, the ion exchange percentage was 66.6%. the formation experiments included mixing the prepared powder of 5a zeolite with different percentages of kaolin clay, citric acid and tartaric acid to form an irregular shape of zeolite granules. tartaric acid binder gives higher bulk crushing strength than that obtained by using citric acid binder with no significant difference in the surface area. 7.5 weight% tartaric acid binder has the higher bulk crushing strength 206 newton with surface area 267.4 m 2 /g. kaolin clay binder with 15 weight% gives the highest surface area 356 m 2 /g with bulk crushing strength 123 newton, it was chose as the best binder for zeolite 5a. the prepared granules of 5a zeolite were used for the adsorption experiments of h2o, and h2s contaminants from lpg. different flow rates of lpg (3, 4, and 5 liter/minute) were studied. it was found that h2o is the strongly adsorbed component and h2s is the weakly adsorbed component. the best flow rate in this work for h2o, and h2s adsorption is 5 liter/minute of lpg. the adsorption capacity for h2o was 7.547 g/g and for h2s was 1.734 g/g. keywords lpg, drying and sweetening, kaolin clay, zeolite 5a, formation, adsorption introduction liquefied petroleum gas (lpg) is the fuel of choice for inhabited areas and for leisure applications. lpg consists of a mixture of propane and butane in various ratios depending on country and season. natural gas and lpg contain sulfur components, either naturally occurring, or added deliberately as odorant to odorize the iraqi journal of chemical and petroleum engineering university of baghdad college of engineering preparation and formation of zeolite 5a from local kaolin clay for drying and desuphurization of liquefied petroleum gas 2 ijcpe vol.14 no.1 (march 2013) -available online at: www.iasj.net otherwise odorless gas. the sulfur removal task for lpg is more challenging than it is for natural gas. propane, butane and heavier hydrocarbons are potential competitors for the sulfur compounds for adsorption sites, decreasing the adsorption capacity. sulfur levels in lpg can be much higher when compared to natural gas [1] . impurities such as h2s in light hydrocarbons usually cause hazardous odors, corrosion problems and air pollution; therefore elimination of these impurities is very important [2] . zeolite adsorbents are used to dry the natural gas or liquefied petroleum gas to prevent freezing and corrosion in pipeline, remove sulfur compounds from the natural gas or liquefied petroleum gas to prevent corrosion in burners, remove compounds that are obnoxious or toxic such as the odoriferous hydrogen sulfide and mercaptans that form sulfur dioxide pollutants when burned for home cooking and heating [3] . zeolites are generally available in bound forms where the zeolite crystals (1–5μm) are formed in particle shapes (beads, pellets, extrudates) using a binder material (clay, alumina, polymers, etc.). the purpose of the bound forms (diameters of 0.5–6.0 mm are common) is to reduce the pressure drop in adsorbent columns [4] . fixed bed adsorption has been used widely in separation and purification of gases and liquids. the breakthrough curves are perhaps the most common basis for assessing the behavior of adsorbers [5] . an examination of the breakthrough curve gives an estimate of the adsorptive capacity of the bed [6] . the breakthrough curve for a particular component is obtained by measuring its concentration in the effluent streams as a function of time until equilibrium is obtained. the concentration of a component in the effluent streams at the beginning is zero until breakpoint, at which the concentration rises gradually to the initial value of the inlet stream [7] . inoue & tsunoi [8] produced shaped zeolite from a mixture of zeolite, poly carboxylic acid binders, kaolin clay binder, and water. the binder amount was about 1-10 wt. %. tartaric acid binder gives crushing strength 12n/mm 2 , while kaolin clay gives crushing strength 5 n/mm 2 . kikkinides, et al. [9] studied the removal of h2s from pre-dried natural gas contains 1000 ppm h2s and 5% co2 by zeolite 5a. the purified adsorption product contains one ppm h2s. chantawong & harvey [10] synthesized zeolite a from kaolin by hydrothermal treatment with various concentrations of naoh solutions (0.5 4n) crystallized at 100 °c for 1 to 5 hours. solid to liquid ratio was 1 gram metakaolin to 20 milliliter naoh solution. the best crystallinity of zeolite was obtained at 2n naoh solution with 4 hours. ugal, et al. [11] studied the preparation of zeolite 4a from iraqi kaolin. metakaolinite was treated with 8m sodium hydroxide solution with a solid: liquid ratio of 1: 5 at 90 °c for 4 h. the obtained zeolite powder was mixed with 15 % raw metakaolinite, and calcined for 4 h at 500° c. the crushing strength of the prepared zeolite was 16 newton and the adsorption capacity was 23 h2o/100g. the aim of this study was preparation of 5a zeolite from local kaolin clay by preparing 4a zeolite and study the effect of different temperatures and concentrations of sodium hydroxide solutions on the degree of relative crystallinity, studying the formation of the prepared 5a zeolite with different contents of abdul-halim a. mohammed and zeinab k. nassrullah -available online at: www.iasj.net ijcpe vol.14 no.1 (march 2013) 3 kaolin clay, citric acid, and tartaric acid, finally, studying the adsorption performance of the prepared 5a zeolite granules in the drying and desulfurization of liquefied petroleum gas. experimental work materials liquefied petroleum gas (lpg) lpg was supplied by midland refineries company/al-durra refinery. the analysis of the lpg was done by al-durra refinery and tabulated in table 1. table 1, lpg analysis test result chemical analysis (vol. %) ethane 0.14 propane 34.62 iso butane 19.96 n. butane 45.22 iso pentane 0.06 specific gravity 0.564 vapor pressure @ 37.8°c, kg/cm 2 7.36 95% of lpg volatized at, °c -1 kaolin clay kaolin clay was supplied by the state company of geological survey and mining. it is available in dewekhala quarry in al-anbar region. table 2 shows the chemical composition of kaolin clay. table 2, chemical composition of local kaolin clay component sio2 al2o3 fe2o3 cao na2o l.o.i wt% 49.7 34.1 1.8 1.1 0.5 12.3 chemicals the chemical compounds are tabulated in table 3. table 3, chemical compounds compound company purity hydrochloric acid gainland chemical company gcc, uk 35-36% sodium hydroxide riedel-de haën ag seelzehannover 98% calcium chloride weifang bell chemical co., ltd., china 98% silver nitrate tianjin yinlida chemicals co., ltd., china 99% citric acid anhydrous fluka ag, ch-9470 buchs, switzerland 99.5% tartaric acid crystals hopkin and williams, england 99.5% silica gel thomas baker chemicals , india water adsorption capacity 30% of its weight preparation of 5a zeolite 1local kaolin clay was crushed and sieved to the grain size -75 micron. the sieved kaolin mixed with hydrochloric acid solution 1n with a solid to liquid ratio (3 g: 10 ml), the mixture was agitated and heated at 100°c for 30 minutes [12] . 2the acid treated clay was washed with deionized water and filtered several times until the washing water was free from chloride ions. this was showed by adding several drops of 0.1n silver nitrate solution to the filtrate. 3the dried treated kaolin clay was calcined at 550°c for 2 hour to convert kaolin to metakaolin [13] . 4the metakaolin was grained, sieved to the particle size -75 micron, treated with different concentration of sodium hydroxide solutions (1, 2, preparation and formation of zeolite 5a from local kaolin clay for drying and desuphurization of liquefied petroleum gas 4 ijcpe vol.14 no.1 (march 2013) -available online at: www.iasj.net 3, and 4n). the metakaolin powder to sodium hydroxide solution ratio was (1 g: 5 ml) [14] . the mixture was aged for 24 hours at room temperature [15] . the reaction mixture was agitated and heated at different temperatures (40, 60, 80, 90, and 100 °c) for 2 hours [16] . the mixture was filtered and washed with deionized water to remove the excess of alkali, decanted and filtered several times till the ph reaches 10.5, then dried at 100°c for 4 hours and milled to the particle size -63 micron. 5sodium zeolite 4a was converted to calcium zeolite 5a by ion exchange with 1.5n calcium chloride solution by heating at 90°c for 5 hours then filtered and washed several times with deionized water until removing all the ions of chloride by adding drops of 0.1 n silver nitrate solution to the filtrate. the extent of exchange was determined using equation (1) by chemical analysis of zeolite before and after ion exchanging with calcium chloride solution [17] . …(1) pelletizing of zeolite 5a different types of binders were used in the formation of zeolite granules. these are tartaric acid, citric acid [8] , treated kaolin clay [18] as shown in table 4. table 4, the mixtures of zeolite 5a and binders binder treated kaolin clay -63 micron citric acid crystal tartaric acid crystal wt% 10 15 20 2.5 5 7.5 2.5 5 7.5 water is used in an amount 60% weight of the mixtures of zeolite and binder. the formation of the pastes of zeolite and binder was done by using the oedometer instrument. the paste after compression was left at room temperature to the next day to let the excess water in the paste be vaporized slowly then dried at 100°c for 24 hours. zeolite disks contained organic binder, citric and tartaric acid, were calcined at 350°c for 2 hours, while zeolite disks contained kaolin clay as a binder calcined at 550°c for 2 hours. the disks were crushed into small piece and sieved to the grain size -2.36 + 0.85 mm. the zeolite granules were tested for determining surface area, bulk crushing strength, and bulk density. the zeolite-binder mixture which gives the best properties was chosen for purification of liquefied petroleum gas. adsorption performance experiments the adsorption performance experiments were carried out in the laboratory unit consist flow gas control board, adsorption column, and hygrometer. the adsorption unit has adsorption column of 2.5 cm diameter and 37.5 cm height. figure (1) shows the flow diagram of adsorption unit. 1lpg cylinder, 2flowmeter and pressure gauge, 3water container, 4adsorption column, 5hygrometer, 6-h2s gas sampling balloon fig. 1, flow diagram of the adsorption process 1 2 3 4 5 6 v-3 v-3 1 abdul-halim a. mohammed and zeinab k. nassrullah -available online at: www.iasj.net ijcpe vol.14 no.1 (march 2013) 5 different flow rates of lpg (3, 4, 5 liter/minute) were studied. test methods chemical composition the chemical composition of prepared zeolite samples was done by the laboratories of the state company of geological survey and mining, ibn sina state company, and petroleum research and development center. x-ray diffraction x-ray diffraction analysis was done in the state company of geological survey and mining by using maxima xrd-7000 diffractometer/japan. bet surface area the surface area of zeolite granules was determined in the petroleum research and development center by using surface area analyzertherm/usa. bulk density bulk density is determined in the petroleum research and development center by using tap density. bulk crushing strength the bulk crushing strength of the zeolite granules was obtained by using the testing device crush bk – crush strength from ma materials technologies, usa) determined in the petroleum research and development center. this device is used for measuring the crush strength of solid materials, their size can be as small as 1 mm and up to about 20 mm. concentration of h2o and h2s the concentration of h2o in lpg was measured by hygrometer device shaw, alpha moisture system and h2s was measured by the tutwiler method (uop) 9-59. results and discussion preparation of zeolite 5a the chemical analysis of kaolin clay before and after the treating with the dilute hydrochloric acid and metakaolin calcined at 550°c is shown in table 5. table 5, the chemical composition of locally kaolin clay before and after treating with dilute hcl, and metakaolin na2o l.o.i fe2o3 al2o3 sio2 weight % 0.50 12.30 1.80 34.10 49.70 kaolin clay before washing 0.06 12.47 0.17 34.62 49.56 kaolin clay after washing 0.09 3.14 53.20 37.50 metakaolin the fe2o3 percentage was reduced by 90%. the iron contaminants occur in the kaolin as goethite, hydrogoethite, they may also enter into the kaolinite lattice, in which case the iron is uniformly distributed and firmly bound throughout its mass [19] , in this case it is difficult to remove iron from the clay. due to the dehydroxylation, sio2 and al2o3 percentages increased from 49.56% and 34.62% to 53.20% and 37.50% respectively, while l.o.i% was decreased from 12.47% to 3.14%. for evaluation the relative crystallinity of prepared 4a zeolite at different temperatures and naoh concentrations, x-ray diffraction analysis was done and compared with standard sodium zeolite 4a. the strongest relative intensities peaks for reference zeolite 4a and the prepared samples of zeolite 4a were determined at the values of 2θ = 7.18°, 10.17°, 12.46°, 16.11°, 21.6°, 23.99°, 27.11°, and 29.94°. the values of the strongest intensity peaks were used for determination the area under the peaks of the strongest intensities. the values of the area under the peaks were used for estimation of relative crystallinities% by equation (2) [20] . preparation and formation of zeolite 5a from local kaolin clay for drying and desuphurization of liquefied petroleum gas 6 ijcpe vol.14 no.1 (march 2013) -available online at: www.iasj.net …(2) where sx = sum of integral peak intensities for the sample 4a sr = sum of integral peak intensities for the reference 4a figure (2) shows the effect of temperatures and naoh concentrations on the relative crystillanity. fig. 2, the effect of temperatures and naoh solutions concentration on the relative crystallinities% of the prepared samples of zeolite 4a figure (2) shows that no relative crystillanity was observed at temperatures 40 and 60°c with all naoh concentrations. when the temperature was increased (80, 90, 100 °c) the crystallinity of 4a was appeared except with 1n naoh concentration. higher relative crystallinities were obtained at 80 °c and 3n naoh concentration (199%), at 90°c and 2n naoh concentration (184%), and at 100°c with 2n naoh concentration (189%). the crystallinity begin slightly to decrease at naoh concentration of 3n at higher temperatures (90 and 100°c) and 4n at 80°c. this decrease may be due to the increase in the concentration of oh which can cause as consequence a change in the resulting zeolite composition which may lead to the formation of sodalite in place of zeolite a [21] . sodalite structurally similar to zeolite a but it is more compact and has much less void space available to water molecules [22] . the negative effect of increasing the concentration of naoh also pointed out by haden, et al. [23] , wongwiwattana [24] , and chantawong, et al. [10] . it could be said that the best temperature of crystallization and naoh concentration for synthesis 4a was 90°c and 2n respectively. although 100°c gave slightly higher crystallinity than 90°c, temperature 90°c was preferred in order to reduce the observed bubbling and solution vaporization at temperature 100°c. temperature 80°c gives moderately higher degree of crystallinity but it was not the choice for the best operating temperature because it needs to high concentration of naoh solution (3n). table 6, the chemical composition of 4a zeolite prepared at 90°c and 2n component sio2 % al2o3% na2o% weight% 44.17 28.13 12.63 the chemical analysis of calcium ion exchange zeolite is shown in table 7, while figure (3) shows the x-ray diffraction of calcium-exchanged zeolite 5a. table 7, chemical composition of calcium zeolite 5a component sio2 al2o3 na2o cao weight % 42.70 25.32 4.23 11.20 sio2/al2o3 2.86 abdul-halim a. mohammed and zeinab k. nassrullah -available online at: www.iasj.net ijcpe vol.14 no.1 (march 2013) 7 fig. 3, x-ray diffraction pattern of zeolite 5a in the exchange operation of calcium for sodium at least about 25% of the sodium originally present in the zeolite 4a zeolite should be replaced by calcium to obtain effective pore size (approximately 5å). the percentage of ion exchange of this study estimated by equation (1) was 66.6%. this result is within the range of the prepared ion exchange 5a zeolite by pacaud, et al. [18] . in the formation of 5a zeolite the dried formed 5a zeolite with kaolin clay binder was calcined at 550 °c, while those formed with citric acid and tartaric acid were calcined at 350 °c. the selected calcination temperatures is compatible with temperature at which the zeolite 5a is thermally stable, the temperature at which the clay binder undergoes an irreversible phase change, the temperature which is sufficiently high to burn off the poly carboxylic acid, and the minimum temperature for calcination is that temperature at which the loss of the water of hydration of zeolite will be affected. zeolite 5a is thermally stable at 700°c but at 800°c converted to amorphous material. kaolin clay binder converts to an amorphous (metakaolin) binder at 550°c to improve the mechanical strength and reduce the infiltration of water and solution through the formed sample. the prepared shaped bodies with polycarboxylic acids binders are calcined at 350°c which is sufficiently high to burn off the organic acid. after drying, calcination, crushing, and sieving of the prepared bounded zeolite to the particle size (-2.36mm) – (+0.85 mm), the physical properties (surface area, bulk crushing strength, and bulk density) were determined and the results are shown in table 8. table 8, the result of binder types and quantity on the physical properties of 5a zeolite granules binder weight % surface area (m 2 /g) bulk crushing strength (newton) bulk density (g/cm 3 ) citric acid 2.5 5 0.619 citric acid 5 289.6 9 0.615 citric acid 7.5 258.2 97 0.623 tartaric acid 2.5 16 0.580 tartaric acid 5 270.5 120 0.549 tartaric acid 7.5 267.4 206 0.553 kaolin clay 10 81 0.612 kaolin clay 15 356 123 0.597 kaolin clay 20 284.6 181 0.592 preparation and formation of zeolite 5a from local kaolin clay for drying and desuphurization of liquefied petroleum gas 8 ijcpe vol.14 no.1 (march 2013) -available online at: www.iasj.net table 8 shows that citric acid binder gives low crushing strength with 2.5 weight% and 5 weight% (5 and 9 newton respectively). increasing the binder content to 7.5 weight% the bulk crushing strength highly increased (97 newton) resulting in surface area decreasing. tartaric acid gives low bulk crushing strength with 2.5 weight% (16 newton), and increasing the tartaric content up to 7.5 weight%, increases crushing strength up to 206 newton. samples with tartaric acid binder have higher bulk crushing strength than those obtained by using citric acid binder in the same percentages with no significant difference in the surface area. the good results of tartaric acid binder may be due to the hydroxyl groups in the organic binder. the organic binder with short chain (tartaric acid) adsorbed on the surface of particles and during the drying, water eliminated from hydroxyl group produces tridimensional hydrogen bonds (among the molecules of binder distributed on the surface of the particles). the development of the stronger tridimensional structure and mechanical strength improves proportionally to the amount of organic binder. tartaric acid has two hydroxyl groups, while citric acid has only one. citric acid has longer chain compared with tartaric acid, it may be during drying does not adsorbed at the surface of particles but they are able to form tridimensional hydrogen bonds [24] . samples with 10, 15, and 20 wt. % kaolin clay binder were prepared. sample with 10 wt. % gives the lowest bulk crushing strength 81 newton, while with 15 and 20 wt. % gives 123 and 181 newton respectively. increasing the bulk crushing strength for 15 and 20 wt. % was accompanied with a decreasing of the surface area from 356 to 284.6 m 2 /g. the addition of a clay binder may reinforce the mechanical properties of the adsorbent, resulting in significant reduction in the adsorbent properties as mentioned by pacaud, et al. [18] and shams & mirmohammadi [26] . the best result among the tested samples of zeolite with different percentages of binders was obtained with 15% kaolin clay and 7.5% tartaric acid. the using of 15% clay gives surface area 356m 2 /g and bulk crushing strength 123 n, while 7.5% tartaric acid binder gives lower surface area 267.4 m 2 /g and higher bulk crushing strength 206 n. this agreed with inoue, et al. [8] . since the adsorption processes depends mainly on surface area and the bulk crushing strength 123n was acceptable, it could be desired that 15% kaolin clay binder is the choice. furthermore kaolin is locally available and so cheap. the 15% kaolin clay percentage is less than that chosen by golovko, et al. [27] and ahmed [28] , they choose kaolin clay with 20-25weight% as the most suitable binder. this result agrees with the result obtained by mahdi [29] who choose 10-20% clay binder. adsorption performance of the prepared 5a zeolite granules the prepared granules of 5a zeolite were used for the adsorption of h2o, and h2s contaminants from lpg. the inlet concentration of h2o was 500 ppm, and h2s was 209 ppm. figures (4) to (6) show the effect of different flow rates (3, 4, 5 liter/minute) on the breakthrough curve of adsorbed h2s and h2o. figures (4) (6) show that the adsorption of h2o at any flow rates is stronger than the adsorption of h2s. the breakpoint time for h2o is higher than that for h2s, for example, at 5 liter/minute, the break point time increases for h2s and h2o from 15 minute to 130 minute respectively. abdul-halim a. mohammed and zeinab k. nassrullah -available online at: www.iasj.net ijcpe vol.14 no.1 (march 2013) 9 this may be due to the higher affinity and smaller diameter of h2o than h2s and hence enhancing the adsorption of the h2o [30] . since the h2o has stronger adsorption affinity than h2s, h2o displaced h2s from the surface of adsorbent and h2s concentration increased in the effluent stream and became higher than the inlet gas concentration (i.e. c/c0 > 1), see figure (4) and (5), this displacement of a relatively weakly adsorbed component by a more strongly adsorbed component is sometimes referred to as roll-up effects mentioned by chi & lee [31] . figures (4) and (6) also show that the breakpoint appears earlier by increasing the flow rate. this may be due to the reduction in thickness of the surface film which considers as a resistance for the mass transfer and consequently an increase the mass transfer rate and hence causes increasing of the adsorption rate as mentioned by nasir [32] , furthermore ali [33] mentioned that increasing flow rate will ease the penetration and the passage of the adsorbate molecules through the particles. dynamic adsorption capacity of zeolite 5a is calculated from summation of accumulative adsorption after a given time by equation (3). where, qi = the quantity of the h2o or h2s adsorbed per unit mass of 5a zeolite adsorbent at any given time, grams adsorbate/gram adsorbent. co = initial concentration of adsorbate (h2s or h2o), grams/liter. ci = effluent concentration of adsorbate at a given time, grams/liter. m = mass of adsorbent, grams. q = volumetric flow rate, liter/minute. t = time of sampling, minutes. figures (7) (9) show the accumulative adsorbed of h2s and h2o verse time at different flow rates. these figures indicate that the amount of h2o adsorbed is higher than that of h2s at any time and flow rate. the lower uptake of h2s in zeolite can be explained by hindrance of the water molecules strongly adhered to the adsorbent surface; even an extremely dilute amount of water can substantially decrease the adsorption capacity for other gases on zeolites and lower their intracrystalline diffusivity [34] . this result is agree with the work chi & lee [31] and kikkinides, et al. [9] . the capacity of zeolite 5a for h2o adsorption decreases with flow rate increasing from 20.61 to 7.54 g/g of zeolite because increasing in the flow rate decreases the contact time between the water vapor and adsorbent. this result agrees with zangana [35] . because of the decreasing the adsorption capacity of h2o the adsorption capacity of h2s increases with flow rate increasing, for example, increasing the flow rate from 3 to 5 liter/minute increases the capacity of h2s from 2.69 to 1.76 g/g of zeolite [36] . fig. 4, breakthrough curve for adsorption of h2s and h2o at 3 liter/minute preparation and formation of zeolite 5a from local kaolin clay for drying and desuphurization of liquefied petroleum gas 10 ijcpe vol.14 no.1 (march 2013) -available online at: www.iasj.net fig. 5, breakthrough curve for adsorption of h2s and h2o at 4 liter/minute fig. 6, breakthrough curve for adsorption of h2s and h2o at 5liter/minute fig. 7, the accumulative adsorbed of h2s and h2o verse time at flow rate 3 liter/minute fig. 8, the accumulative adsorbed of h2s and h2o verse time at flow rate 4 liter/minute fig. 9, the accumulative adsorbed of h2s and h2o verse time at flow rate 5 liter/minute conclusions 1x-ray diffraction analyses show that temperatures 40 °c and 60 °c did not show any relative crystallinity of zeolite 4a. at all other temperatures with 1n naoh concentration no crystallinity was observed. temperature 90 °c with 2n naoh concentration was selected to prepare zeolite 4a from kaolin. 2the percentage of ion exchange of zeolite 4a with calcium chloride solution was 66.6%. 3the formation experiments of 5a zeolite with organic binder showed that tartaric acid binder gave higher bulk crushing strength than that obtained by using citric acid binder in the same percentages with no significant difference in the surface area. 7.5% tartaric acid gives the higher bulk crushing strength 206 n with surface area 267.4m 2 /g. 4the prepared zeolite with 15wt. % kaolin clay binder gave the higher surface area 356 m 2 /g, and bulk crushing strength 123 n. 5the adsorption of h2o and h2s from lpg using the prepared granules of 5a zeolite showed that h2o is the strongly adsorbed component compared with h2s. this affinity toward h2o affected on the breakpoint time for h2o which appeared very late. abdul-halim a. mohammed and zeinab k. nassrullah -available online at: www.iasj.net ijcpe vol.14 no.1 (march 2013) 11 6the capacity of the prepared zeolite 5a for adsorption of h2s increases with flow rate increasing, while for h2o the capacity decreases with flow rate increasing. references 1de wild, p. j., nyqvist, r.g., de bruijn, f.a. and stobbe, e.r., removal of sulfur-containing odorants from fuel gases for fuel cell-based combined heat and power applications, journal of power sources, vol. 159, issue 2, 9951004 pp., (2006) 2ghanbari, k., razmkhah, k., and tajerian, m., design of caustic wash system for light hydrocarbons such as lpg, ngl and naphtha, petroleum and coal, vol. 45, 3-4, 131-134 pp., (2003) 3sherman, j. d. synthetic zeolite and other microporous oxide molecular sieves, proceedings of the national academy of the sciences of the united state of america pnas, vol. 96 (7), 3471 – 3478 pp., (1999) 4auerbach, s. m., carrad, k. a., dutta, p. k., (2003), hand book of zeolite science and technology, marcel dekker, inc., new york. 5park, i., and knaebel, k. s., adsorption breakthrough behavior: unusual effects and possible causes, aiche, vol. 38, no. 5, (1992) 6al-damkhi, a. m., al-ameeri, r. s., jeffreys, g.v. and mumford, c. j. , optimal separation of nparaffins from kuwait kerosene using a molecular sieve adsorbent, j. chem. tech. bioetechnol. 37, 215-228 pp., (1987) 7al-qassab, a. a., (1984), the adsorption of binary and ternary gaseous mixtures on molecular sieves, phd thesis, the university of bath. 8inoue, t., tsunoi, k., process for the production of bonded zeolite bodies, u.s. patent, no.4, 239, 655, (1980) 9kikkinides, e., sikavitsas, v., and yang, r., natural gas desulfurization by adsorption: feasibility and multiplicity of cyclic steady states, ind. eng. chem. res., 34, 255-262 pp., (1995) 10chantawong, n., and harvey, n.w., synthesis of zeolite from thai kaolin for wastewater treatment, proceeding of the 2 nd regional conference on energy technology towards a clean environmental 12-14 february, thailand, (2003) 11ugal, j. r., hassan, k. h., and ali, i. h., journal of the association of arab universities for basic and applied sciences, vol. 9, 1-8 pp., (2010) 12torro, l., marabini, a.m., paponetti, b., passariello, b., process for removing iron from kaolin, quartz and other mineral concentrates of industrial interest ,united state patent, no.5,190,900, (1993). 13breck, d.w., (1974), zeolite molecular sieves: structure, chemistry, and use, john wiley & sons, inc., usa. 14alkan, m., hopa, ç., yilmaz, z., and güler, h., the effect of alkali concentration and solid/liquid ratio on the hydrothermal synthesis of zeolite naa from natural kaolinite, microporous and mesoporous materials, volume 86, issues 1-3, 176-184 pp., (2005) 15miao, q., zhou, z., yang, j., lu, j., yan, s., and wang, j., synthesis of naa zeolite from kaolin source, frontiers of chemical engineering in china, vol.3, no.1, 8-11pp., (2009) 16warzywoda, j., thompson, r. w. zeolites11: 577, (1991), cited by: weitkamp, j., puppe, l., (1999), catalysis and zeolites: preparation and formation of zeolite 5a from local kaolin clay for drying and desuphurization of liquefied petroleum gas 12 ijcpe vol.14 no.1 (march 2013) -available online at: www.iasj.net fundamentals and applications, springer-verlag berlin heidelberg. 17taylor, a. m., roy, r., zeolite studies iv: na-p zeolite and the ion exchange derivatives of tetragonal na-p, the american mineralogist, vol. 49, 656-682 pp., (1964) 18pacaud, b., mercier, n., 5a zeolite/kaolinite adsorbent for gas purification, u.s. patent no.5, 292, 300, (1994) 19komskaya, m. s., yatsunova, s. e., raising kaolin quality by acid processing, glass and ceramics, vol. 26, no. 8, 494-495 pp., (1969) 20astm international, standard test method for determination of relative crystallinity of zeolite sodium a by x-ray diffraction d 5357-03, (2008) 21gualtieri, m., (2006), synthesis and characterization of zeolite films and membranes, phd. thesis, lulea university of technology, sweden. 22breck, d.w., eversole, w.g., milton, r.m., reed, t.b., and thomas, t.l., crystalline zeolite. i. the properties of a new synthetic zeolite type a, journal of the american chemical society, physical and inorganic chemistry, vol. 78, no. 23, 59663-5971 pp., (1956) 23haden, l. w., metuchen, j., and dzierzanowski, f. j. , base exchange zeolite and method for making the same, us patent, no., 3,112,176, (1963). 24wongwiwattana, j., (2002) synthesis and kinetic study of zeolite naa from thai kaolin, msc. thesis, university of suranaree. 25tozzi, n., binders for ceramic bodies, digital fire ceramics technical articles, (2008), http: //digitalfire.com/ 26shams, k., and mirmohammadi, s.j., preparation of 5a zeolite monolith granular extrudates using kaolin: investigation of the effect of binder on sieving/adsorption properties using a mixture of linear and branched paraffin hydrocarbons, microporus and mesoporous materials, volume 106, issues 1-3, 268-277 pp., (2007) 27golovko, g., a., lipkind, b., a., slepneva,a., t., leontiev, a., t., mazin, v., m., berezovskaya, e., n., burylov, v., a., zubkov, a., m., konakova, o., a. and judaev, i., a., process for the preparation of synthetic zeolite, u.s. patent no.3, 979, 335, (1976) 28ahmed, n.s., (2000), preparation of zeolite 3a and 5a from locally available raw materials and their extrusion with different binders, m.sc. thesis, university of baghdad. 29mahdi, a.s., (1997), preparation of zeolite – binder agglomerates from the locally available raw materials as spherical particles, msc. thesis, university of baghdad. 30thomas, w. j., and crittenden, b., (1998), adsorption technology and design, elsevier science & technology books. 31chi, c.w. and lee, h. (1973) aiche symp. series 69, 95, cited by: thomas, w. j., and crittenden, b., (1998), adsorption technology and design, elsevier science & technology books. 32nasir, m. j., (2010), competitive adsorption of multi-organic compounds onto organoclay from simulated wastewater, ph.d. thesis, university of baghdad. 33ali, a. h., (2011), a comparative adsorption/ biosorption for the removal of organic and inorganic pollutants onto granular abdul-halim a. mohammed and zeinab k. nassrullah -available online at: www.iasj.net ijcpe vol.14 no.1 (march 2013) 13 activated carbon, ph.d. thesis, university of baghdad. 34sircar, s., myers, a., gas separation by zeolite , cited in: auerbach, s.m., carrad, k. a., dutta, p.k., (2003), hand book of zeolite science and technology, marcel dekker, inc., new york. 35zangana, m. h., (2004), study the efficiency of molecular sieve type 4a as drying agent, msc. thesis, university of baghdad. 36nassrullah, z. k., (2012), preparation and formation of zeolite 5a from local kaolin clay for drying and desulphurization of liquefied petroleum gas, msc. thesis, university of baghdad. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.22 no.4 (december 2021) 1 – 10 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name : safa abdul salam kamel, email: safa.kamil1807m@coeng.uobaghdad.edu.iq , name: wadood taher mohammed, email: dr.wadood@coeng.uobaghdad.edu.iq, name: haider a. al-jendeel, email: haider.aljendeel@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. synthesis and characterization of ni-wo3/sulfated zirconia nano catalyst for isomerization of n-hexane and iraqi light naphtha safa abdul salam kamel, wadood taher mohammed, and haider a. al-jendeel chemical engineering department/university of baghdad/baghdad, iraq abstract this work deals with the preparation of sulfated zirconia catalyst (sz) for isomerization of n-hexane model and refinery light naphtha, as well as enhanced the role of promoters to get the target with the mild condition, stability, and to prevent the formation of coke precursors on strong acidic sites of the catalyst. the prepared ni-wo3/sulfated zirconia catalyst was characterized by fourier transform infrared spectroscopy (ftir), x-ray diffraction (xrd), brunauer –emmett-teller (bet) surface area analysis, thermogravimetric analysis (tga), and atomic force microscopy (afm) analyzer. the results illustrate that the maximum conversion and selectivity for n-hexane isomerization with ni-wsz at the operating temperature of 150 °c was 80.1% and 96 % respectively. while the experimental with light naphtha, the results show that the maximum conversion and selectivity with ni-wsz at the operating temperature of 150 °c was 53% and 74% respectively. keywords: light naphtha isomerization, n-hexane, nickel-tungsten, sulfated zirconia, super acidic catalyst, isomerization process received on 07/11/2021, accepted on 19/12/2021, published on 30/12/2021 https://doi.org/10.31699/ijcpe.2021.4.1 1introduction pollution and climate change have made the world more attentive and concerned about the environment in the last few decades. at the same time, the industrial processes in general and oil refinery, in particular, have touched the growing of fuel demand and quality for the combustion engine efficiency of fuel by the research octane number (ron). the distillation of petroleum fractions in the oil refinery industry cannot meet the required properties of gasoline with ron 92 to 100 as needed by modern engines [1]. in the past, as a result, to increase the octane number, many approaches were adopted like adding some addition, this was achieved using lead compounds, i.e., tetraethyl lead that became restricted and prohibited later due to environmental regulation as they are toxic and poison exhaust gas converters. another technique was adopted to enhance the ron is by mixing the fuel with benzene and/or other aromatics, also, the legislation of the acceptable degree of these aromatics in fuel is becoming stricter later, on the other hand, methyl tetra butyl ether (mtbe) has been related to groundwater pollution, although being less hazardous than lead. simultaneously, some of the high-octane components found in gasoline, such as benzene, aromatics, and olefins, must be decreased as well. it will be better to use a technique that will improve the octane of gasoline without adding hazardous or ecologically harmful chemicals [2]. so the oil industry has turned to the modern alternative processes that use catalysts to convert the straight chainalkanes to branched alkanes which have higher octane numbers sufficient to raise the octane rating of gasoline, this is called the isomerization process[3]. hydroisomerization processes frequently necessitate the use of dual-purpose catalysts. with the help of noble metals like platinum and palladium an acid site, a bifunctional catalyst performs two functions: hydrogenation/dehydrogenation and cracking[4]. because of the thermodynamics of isomerization, lower reaction temperatures favor the generation of isoparaffins, hence catalysts that operate at low temperatures are often more selective to isomers than those that operate at high temperatures [5,6]. because of their high acidity and low reaction temperature (about 180°c), platinum-loaded chlorinated alumina catalysts were initially used in industrial isomerization units. however, there are several disadvantages to using this type of catalyst. there are numerous corrosion and environmental issues associated with the use of chlorine in catalyst regeneration [7]. the long life of the pt/cl-al2o3 catalyst necessitates the use of feed and make-up gas driers for the removal of moisture. so there's a strong incentive to find a better, less harmful catalyst for n-alkane isomerization to increase the production of isomerate. zeolites and sz are examples of potential catalysts for n-alkane isomerization that have been proposed in the literature. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:safa.kamil1807m@coeng.uobaghdad.edu.iq mailto:dr.wadood@coeng.uobaghdad.edu.iq mailto:bhaider.aljendeel@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2021.4.1 s. a. kamel et al. / iraqi journal of chemical and petroleum engineering 22,4 (2021) 1 10 2 low reaction temperature favors n-alkane isomerization since it is a mildly exothermic process. catalysts that are active between (100-200) 0 c are thought to be the most appropriate for c4c6 isomerization. despite numerous tries, zeolite catalysts are no longer thermodynamically advantageous for n-alkane isomerization from this point on. zeolite catalysts must be run at a higher temperature, typically 200°c to 300°c. finally, compared to the pt/clal2o3 catalyst, the sz-based catalysts exhibit satisfactory catalytic performance in n-alkane isomerization [8]. because of their high activity, simplicity of handling, and absence of corrosiveness, these catalysts are considered promising industrial catalysts. [9]. the addition of several transition metals to sulfated zirconia, such as pt, pd [10], fe, and mn [8], has been shown to increase the catalytic activity and stability against rapid deactivation. however, ma et al. [11] demonstrated that ni impairs the catalytic efficiency of sulfated zirconia. ni significantly altered the total acidity and concentration of strong acid sites; ni was utilized in place of pt as the active metal phase of various acid solids, and the resulting catalysts were evaluated in hydrocarbon processes. ni is less expensive than noble metals such as pt or pd, thus its use would be costeffective [11]. additionally, modification of sz with additional anions, such as wo3 might result in the formation of strong acid sites on the zirconia surface that are extremely stable[12]. the investigation aims to develop more efficient catalysts consists sulfated zirconia as a based catalyst supported with wo3, ni to improve the isomerization of n-hexane and iraqi light naphtha and to examine in detail the effect of the reaction condition on catalytic activity. 2experimental work 2.1 feedstock midland refineries company/al-dura refinery terminal supplied light naphtha utilized as feed to isomerization unit for activity test. physical properties and composition of the light naphtha listed in table 1 table 1. physical properties and composition of. light.naphtha physical properties value density 0.664 g/cm 3 initial boiling point 36 ℃ end boiling point 84 ℃ sulfur content 1.6 ppm octane number 60 n-paraffin 56.33 wt.% i-paraffin 30 wt.% naphthene 6.78 wt.% aromatic 4 wt.% 2.2. chemicals used table 2 shows the chemicals used with its specifications: table 2. chemical compounds specifications chemicals formula density molecular weight (g /gmol) purity zirconum oxychloride octahydrate zrocl2.8h2o 1.910 g/ml 322.25 99 % ammonia solution nh3 aq. 0.91 g/ml 17.03 25% sulfuric acid h2so4 1.83 g/ml 98.08 98% nickel (ii) nitrate hexahydrate ni(no3)2.6h2 o 2.05 g/ml 290.81 98% ammonium meta tungsten (nh4)6h2w12o 40.xh2o 4.6 g/ml 2956.2 91% w nanoalumina al2o3 3.95 g/ml 101.96 99.99 % poly vinyl alcohol (ch2choh)n 1.19 g/ml 1750 99% n-hexane c6h14 0.655 g/ml 86.18 99% bentonite al2o3.4(sio2). h2o 2~3 g/cm 3 360.31 98% 2.3. preparation of catalyst 150 g of zirconium oxy-chloride salt (zrocl2.8h2o) was dissolved in 2000 ml of deionized water and ammonia solution of about 25% concentration added drop by drop above the solution above under vigorous stirring until the ph of the slurry reached (8), keeping the slurry for extra time of about 0.5 hr and aged it at room temperature for 16 hr to allow zirconium hydroxide zr(oh)4 enough time to precipitate. then, the precipitate of zirconium hydroxide was filtered under vacuum condition, washed with the access of deionized water to remove chlorine ions and get acidity of about 7, drying the sample at 100 °c for 15 hr. thereafter, hydrous zirconia was grounded to a fine powder and the sulfation process was carried out by wet-impregnating the sample with h2so4 of 1 mol/l at 2 ml/g for 1hr. , then, submit the sulfated zirconia produced to dried at 100 °c for 15 hr by the digital dryer and calcined at 600 °c for 3 hr [13]. the wet-impregnation method was adopted to add nickel and tungsten promoters. firstly, sz was impregnated with an aqueous solution of nickel nitrate (ni(no3)2.6h2o) as shown in fig. 1, to prepare 1% ni sz catalyst which was dried at 110° c and calcined at 450°c in the air for 3 hr. thereafter, an aqueous solution of ammonium metatungstate ((nh4)6(h2w12o40.nh2o) was used to impregnate ni/sz catalyst by dropwise mechanism to load 25% wo3 on it. then, the produced catalyst was left for 24 hr at room temperature and then dried overnight at 110 °c and calcined in air at 700 °c for 3 hr. finally was extruded the catalyst by mixed with 20% nano alumina, 10% bentonite, and 7% polyvinyl alcohol solution (pva) as binders with (0.65 cm length and 0.12 cm diameter) as shown in fig. 2, a by formulating machine of catalyst as shown in fig. 2, b. s. a. kamel et al. / iraqi journal of chemical and petroleum engineering 22,4 (2021) 1 10 3 fig. 1. scheme of impregnation apparatus (a) (b) fig. 2. a. catalyst formation extruded of powder ni-wo3/ sz, b. formulating machine of catalyst 2.4. catalytic activity test 7 g of (ni-wo3/sz) catalyst was used in a fixed bed reactor in its designated area of the reactor between two layers of inert ceramic balls material of about 5 mm diameter to ensure a uniform flow and an effective surface area for the catalysts. in the beginning, the nitrogen is passed into the reactor to release the air from the system. at the same time, the reactor is heated to the temperature required for that experiment. and at this moment, the nitrogen passage valve is closed and the reactor is feeding with n-hexane model fuel (or light naphtha) through dosing pump and hydrogen through the control valve, which they mixed in the zone ahead of the experimental reactor. the mixture will pass over the catalyst in the reactor and the reaction will occur. the product of the reactor will be cooled by a refrigerant system and the hydrogen will be separated by a highpressure separator. at the steady-state operation, the product of the reactor will be sent to the gas chromatography analyzer (gc). the isomerization unit is represented in fig 3 the reaction conditions for isomerization of n-hexane (or light naphtha) are shown in table 3 below: table 3. operating condition of n-hexane isomerization process feed n-hexane or light naphtha catalysts used are ni-wo3/sz or pd-wo3/sz reaction temperature 120 c – 250 c operating pressure 6 bar mole ratio of h2/hc 4 liquid hour space velocity ( lhsv) 1 hr. -1 (a) s. a. kamel et al. / iraqi journal of chemical and petroleum engineering 22,4 (2021) 1 10 4 (b) fig. 3. . isomerization process, a. schematic representation of isomerization unit, b. isomerization unit 3characterization of synthesized catalysts the first part of this study is represented by preparing ni/wo3-sz catalyst by two steps (precipitation impregnation method) and characterizing it for isomerization of iraqi light naphtha and n-hexane. this characterization includes; x-ray diffraction (xrd), fourier transform infrared ftir spectroscopic, atomic force microscope (afm). 3.1. x-ray diffraction (xrd) sulfated zirconia modified with wo3 and ni as promoters improve the catalytic activity of the isomerization process and support the catalyst stability against the rapid deactivation. the promotion of sulfated zirconia with promoters causes the change in the crystal structure accompanied by changes in the textural properties of the synthesized catalyst. figure 4 showed the xrd pattern of the ni-wo3/ sz catalyst. the results showed that the presence of wo3 stabilizes zirconia, i.e., supports the tetragonal modification even at low calcination temperature. according to the obtained results, the tetragonal zirconia was about 80% and monoclinic was about 20%. more stabilized tetragonal crystallite phase was obtained with ni loaded as promoters to modify wo3-sz. nickel oxide (nio) particle inhibited the transformation of tetragonal phase to monoclinic phase at calcination stage, also, it can be seen decreasing crystallite size due to dispersed nio along with modified sulfated zirconia can restrain the agglomeration of tetragonal sz grains, besides that, there is a strong interaction between nio partials and sulfated zirconia. on the other hand, no diffraction peaks assigned to nio can be detected, meaning the metal promoters are well dispersed in the base and have a very small crystal size [14, 15]. fig. 4. xrd patterns of ni-wo3 / sz catalyst 3.2 fourier – transform infrared spectroscopy (ftir) characterization fig. 5 illustrates the ftir analysis for prepared sulfated zirconia catalyst, ni-wsz catalyst. this technique measured the chemistry of the catalyst surface included the acidity of the active sites. ftir results of the study illustrated the absorption bands along the wavenumber 500-4000 cm -1 , in which, the wavenumber of 500-600 cm -1 corresponded to presence (zr─o─zr) bond, the wavenumber of (33003750) cm -1 was corresponded to the presence the vibration of (o-h) bond, while, the absorption bond of so4 -2 appears at wavenumber of 100-1500 cm -1 . this observation indicated the appearance of a covalent (s═o) double bond on the surface of sulfated groups at the catalyst which strongly affects the acidity and meets the requirement of the isomerization process. these results were in very good agreement with other authors. hauli et al., [16], had studied the preparation and characterization of the sulfated zirconia catalyst from zirconia nano-powder. their results confirm that the characterization of catalyst is highly dependent on sulfonation mechanism and calcination temperature, the results ensure that the so4 -2 peak would appear at a higher concentration of h2so4 in sulfonating step and gradually disappear as the calcination temperature increase. s. a. kamel et al. / iraqi journal of chemical and petroleum engineering 22,4 (2021) 1 10 5 fig. 5. ft-ir spectra of ni-wo3/ sz fig. 6. 3 -d and 2-d surface profiles of ni-wo3/modified sz 3.3. atomic force microscope (afm) characterization atomic force microscopy is a powerful technique that can image almost any type of surface, it is used to measure the particle size distribution of the catalyst. the average particle distribution after loaded metal on the catalyst, such as ni-wo3 /modified sz catalyst was 9.27nm with partial size dimeter range not exceeding 24.36 nm. 2 and 3 dimension of surface profiles of niwo3/ sz as shown in fig. 6. the preparation mechanism affects the partial size distribution of sulfated zirconia catalyst, in particular, the sulfonating mechanism. sulfate anions increase the surface area, support the stability of the tetragonal phase and minimize the crystallite size. seen decreasing crystallite size due to dispersed nio along with modified sulfated zirconia can restrain the agglomeration of tetragonal sz grains, besides that, there is a strong interaction between nio partials and sulfated zirconia. 4catalysts activity the experimental runs were carried out for isomerization of refinery light naphtha and n-hexane model to improve the octane number using prepared novel catalysts consisting of sulfated zirconia, as the base with its promoters ni/wo3sz. the effect of reaction temperature (130-250 °c) was studied, keeping other variable content, lhsv of 1 hr -1 , mole ration of h2/hc of 4, and constant operation pressure of 6 bar. 4.1. ni/wo3sz activity for isomerization of n-hexane model fuel table 4 shows the chemical composition of the isomerization product by using pona analysis to evaluate the catalyst performance. s. a. kamel et al. / iraqi journal of chemical and petroleum engineering 22,4 (2021) 1 10 6 table 4. pona analysis for isomerization of n-hexane at lhsv = 1 hr-1 and different temperature n-hexane 130°c 150°c 170°c 200°c 250°c n.paraffine 99 35 20 27 36.4 42 i-paraffine 1 62 77 68.7 59 53 naphthene 0 1.7 2 2.8 3 3 aromatic 0 1.3 1 1.5 1.6 2 a. n-paraffin conversion the results are illustrated in figure 7, which represents the n-paraffin conversion as a function of operating temperature. the conversion of n-paraffin to i-paraffin, naphthene, and aromatic compounds was started at 130 °c in many different proportions toward i-paraffin. thereafter, it keeps up from 65% to 80% at 150 °c, which represents the maximum conversion obtained in this set of research. then, it decreases to 73%, 63.6%, and 58% at 170°c, 200°c, and 250 °c respectively. the results of this research are good and encouraging start in the field of petroleum research that uses a significant acid-grade catalyst that matches the requirement of the process at mild conditions as discussed later with other accompanying conditions. the maximum conversion achieved was 80% that represents one of the highest degrees as compared with other researchers that used zirconia-based catalyst. m. busto et. al. [18] discovered new paraffin isomerization catalysts based on pt/sz, maximum conversion achieved of about 95% at 230 °c. torres et.al. [19], studied modification of wo3-zro2 catalyst by metal addition, maximum conversion achieved was about 70%. ma et.al.[11], studied pd-ni doped sulfated zirconia for isomerization of n-hexane, maximum conversion achieved was about 70%. fig. 7. effect of temperature on isomerize conversion of n-hexane over ni-wo3/ sz b. i-paraffins, naphthenes, and aromatic selectivity and yield operation temperature has a major impact on the isomerization process, in particular, on the conversion of the feed to isomer product and its accompanied naphthenes and aromatic and others when the temperature exceeds the limits of isomerization process. fig. 8 and fig. 9 illustrate the effect of temperature on isomer compounds, naphthenes, and aromatic selectivity and yields. the results indicate that the isomer's selectivity begins with a maximum degree of 96% at 150 °c and went on with a slight decrease to meet 90% at 250 °c. at the same time, naphthenes were detected at 130 °c with a 2.6% with a slight increase of only 5.1% at 250 °c. also, aromatic compounds were detected with 2% at 130 °c and a slight increase reaching 3.4% at 250 °c. also, the results indicate that the isomers yield begins with a maximum degree of 77% at 150 °c and went on with decreased to reach 53% at 250 °c. at the same time, naphthenes were detected at 130 °c with 1.7% with a slight increase of only 3% at 250 °c. also, aromatic compounds were detected with 1.3% at 130 °c and a slight increase reaching 2% at 250 °c. these results with mild conditions accompanied the operation refers to the suitable catalyst used and isomerization operation conditions. fig. 8. effect f temperature on the selectivity of iparaffins, naphthenes, and aromatic compounds over niwo3/ sz catalyst https://www.sciencedirect.com/science/article/pii/s0378382012001695#! s. a. kamel et al. / iraqi journal of chemical and petroleum engineering 22,4 (2021) 1 10 7 fig. 9. effect of temperature on yield of i-paraffins, naphthenes, and aromatic compounds over ni-wo3/ sz catalyst from n-hexane feed 4.2 ni-wo3/sz activity for isomerization of light naphtha table 5 shows the chemical composition of the isomerization product by using pona analysis to evaluate the catalyst performance. table 5. pona analysis for isomerization of iraqi light naphtha at lhsv = 1 hr-1 and constant pressure 6 bar l.n 130°c 150°c 170°c 200°c 250°c n.paraffine 56.33 43 26.4 37.7 40.7 42.5 i-paraffine 33 41 49.5 45.2 41.5 37.2 naphthene 6.78 9 13.9 11.4 9.6 10.8 aromatic 4 7 10.1 5.9 9 10 a. light naphtha (n-paraffin) conversions the results obtained here indicate that the conversion of n-paraffin started at 130 °c with 23.7% and reached its maximum value at 150 °c with 53%. hereafter, the conversion was slightly reduced to meet 24.5% at 250 °c as shown in fig. 10. these expected results are in agreement with other authors, due to all the conditions related to the preparation of the catalyst on one side, and to the operational conditions on the other side, as well as, the massive competition of the molecules included the light naphtha composition, i.e., i-paraffines, naphthenes, and aromatics, besides, the intermediate compounds formed during the reactions which largely affected the acidity active sites of the catalysts. fig. 10. effect of temperature on isomerization conversion of light naphtha over ni-wo3/ sz catalyst b. i-paraffins, naphthenes, and aromatic selectivity and yield in general, catalytic operations are so complex it depends on many variables, catalyst characterization, petroleum fractions, and their compositions, and the operating conditions the results of this set of experiments observed the presence of naphthenes, and aromatics compounds besides the isomers compounds. the selectivity to isomers started to increase at 130 °c with the value of 72% and reach the maximum at 150 c with 74%, hereafter; the selectivity began to reduce and had 72%, 68%, and 64% at 170 °c, 200 °c, and 250 °c respectively. this behavior was in agreement with other anthers due to the presence of many intermediate compounds that affect the acidic active sites of the catalyst. also, the results showed that the presence of naphthenes during the reaction, the selectivity 15%, 19%, 18%, 16 %, and 18% was at 130°c, 150°c, 170 °c, 200°c, 250°c respectively, and the aromatic compounds with the selectivity of 12 %, 14%, 9%, 15%, and 17% at the above operating temperature respectively. this appearance was due to the conversion of n-paraffin to i-paraffin, naphthene, aromatics besides the various behaviors expected by the specialist authors in this field. fig. 11 and fig. 12 illustrate the effect of temperature on isomer compounds, naphthenes, and aromatic selectivity and yields. fig. 11. effect of temperature on selectivity of i-paraffins, naphthenes, and aromatic compounds over niwo3/modified sz catalyst from light naphtha s. a. kamel et al. / iraqi journal of chemical and petroleum engineering 22,4 (2021) 1 10 8 fig. 12. effect of temperature on yield of i-paraffins, naphthenes, and aromatic compounds over niwo3/modified sz catalyst from light naphtha many studies have tried to determine the nature of the acidity active sites (bronsted and/or lewis) on the catalyst surface and the mechanism to obtain them. they found that this matter depends on water content, which depends strongly on the preparation method and its conditions [20]. on the other side, the presence of promoters was found to have a great effect in improving the performance of the catalyst. sulfated zirconia likes another solid acidic catalyst suffers rapid deactivation during hydrocarbon reactions due to the formation of other side reaction production, in particular, coke formation. the addition of some transition metals, i.e., ni to the sz catalyst resulted in a great improvement to the catalyst performance. this was observed from the results of the isomerization process to n-hexane and the refinery light naphtha under mild conditions, which have shown high activity towards isomer compounds. the addition of ni and wo3 to sulfated zirconia improved the performance of the catalyst towards high nparaffins conversion, isomer compound formation, and diminish coke appearance as a cracking reaction. many authors studied and discussed this behavior; they related the phenomena to the dependence of chemical reaction activation energy on the enthalpy of transition state complex formation on the catalyst surface, so the activity of such catalyst depends on the lower value of enthalpy [21]. the effect of hydrogen in the isomerization reaction over the sz catalyst depends on the mechanism of the nparaffin reactions. for the n-paraffins of light naphtha, the hydrocarbon reaction, i.e., isomerization reaction and/or cracking follow a monomolecular mechanism. so the effect of hydrogen will be positive[22]. 5conclusion it is found that sulfated zirconia is considered to be a very important base catalyst throughout its acidic actives that match the requirement of the isomerization process of n-hexane and light naphtha. isomerization of alkanes in the presence of sulfated zirconia catalysts needs mild conditions of operating temperature of about 150°c and pressure of about 6 bar. ni-wsz gives a high conversion at these conditions of about 80.1%, while the selectivity of isomers of about 96 %. references [1] aboul-gheit, a.k., el-desouki, d.s., abdel-hamid, s.m., ghoneim, s.a., ibrahim, a.h., gad, f.k., (2012). "sulfated zirconia catalysts for low temperature isomerization of n-pentane". egypt. j. chem. 55, 509–527. [2] mohamed, m. f., shehata, w. m., halim, a. a., and gad, f. k. (2017) "improving gasoline quality produced from midor light naphtha isomerization unit", egyptian journal of petroleum, 26(1), pp. 111124. [3] aljandeel h.a., hussein h.q.," kinetic study of hydroisomerization of n-decane using pt/sapo11 catalysts", iraqi journal of chemical and petroleum engineering 2018, 19(3), 11-17. [4] aljandeel h.a., hussein h.q.," advanced study of promoted pt /sapo-11 catalyst for hydroisomerization of the n-decane model and lube oil ", iraqi journal of chemical and petroleum engineering 2021, 22(2), 17-26. [5] vu, t. n. et al. (2005), "platinum-tungstated zirconia isomerization catalysts: part ii. effect of platinum and tungsten loading on the mechanism of isomerization of n-hexane: a kinetic study", journal of catalysis, 231(2), pp. 468–479. [6] fa ̌rcas ̧iu, d. and li, j. q. (1995) ‘preparation of sulfated zirconia catalysts with improved control of sulfur content’, applied catalysis a, general, 128(1), pp. 97–105. [7] abudawood, r. h. (2010),"hydroisomerization of alkane over metal-loaded zeolite catalysts" ,chemical engineering and analytical science", ph.d. thesis, university of manchester [8] wang, p., yue, y., wang, t., bao, x. (2020) "alkane isomerization over sulfated zirconia solid acid system", international journal of energy research, 44(5), pp. 3270–3294. [9] li, x. (2004) ,"butane skeletal isomerization on sulfated zirconia at low temperature". thesis, faculty of chemistry at the technical university of munich,german [10] liu, n. et al. (2020) ,"palladium-doped sulfated zirconia: deactivation behavior in isomerization of nhexane", fuel, 262, p. 116. [11] ma, z., meng, x., liu, n., shi, l., (2018). "ni doped sulfated zirconia: study of hydrogen spillover and isomerization of n-hexane". mol. catal. 449, 114–121. [12] shkurenok, v.a., smolikov, m.d., yablokova, s.s., kiryanov, d.i., belyi, a.s., paukshtis, e.a., leonteva, n.n., gulyaeva, t.i., shilova, a. v., drozdov, v.a., (2015)," pt/wo3/zro2 catalysts for nheptane isomerization". procedia eng. 113, 62–67. [13] kamel s.a. , al-jendeel , mohammed w.t., 2021, "preparation of solid-super acidic catalyst with improvement physical properties", materials science forum, vol. 1039, pp 313-325. [14] dzhikiya, o. v., smolikov, m.d., kazantsev, k. v., yablokova, s.s., podmareva, o.e., belyi, a.s., (2019). "the effect of palladium addition to sulfated zirconia catalysts on physicochemical and catalytic properties in the n-hexane isomerization reaction". aip conf. proc. 2141. [15] smolikov, m. d. et al. (2019) "active surface formation of tungstated zirconia catalysts for nheptane isomerization", catalysis today, 329(july 2018), pp. 63–70. https://doi.org/10.21608/ejchem.2012.1171 https://doi.org/10.21608/ejchem.2012.1171 https://doi.org/10.21608/ejchem.2012.1171 https://doi.org/10.21608/ejchem.2012.1171 https://doi.org/10.21608/ejchem.2012.1171 https://www.sciencedirect.com/science/article/pii/s1110062115300945 https://www.sciencedirect.com/science/article/pii/s1110062115300945 https://www.sciencedirect.com/science/article/pii/s1110062115300945 https://www.sciencedirect.com/science/article/pii/s1110062115300945 https://www.sciencedirect.com/science/article/pii/s1110062115300945 https://doi.org/10.31699/ijcpe.2018.3.2. https://doi.org/10.31699/ijcpe.2018.3.2. https://doi.org/10.31699/ijcpe.2018.3.2. https://doi.org/10.31699/ijcpe.2018.3.2. https://doi.org/10.31699/ijcpe.2021.2.3 https://doi.org/10.31699/ijcpe.2021.2.3 https://doi.org/10.31699/ijcpe.2021.2.3 https://doi.org/10.31699/ijcpe.2021.2.3 https://doi.org/10.31699/ijcpe.2021.2.3 doi:%2010.1016/j.jcat.2005.02.003 doi:%2010.1016/j.jcat.2005.02.003 doi:%2010.1016/j.jcat.2005.02.003 doi:%2010.1016/j.jcat.2005.02.003 doi:%2010.1016/j.jcat.2005.02.003 10.1016/0926-860x(95)00077-1 10.1016/0926-860x(95)00077-1 10.1016/0926-860x(95)00077-1 10.1016/0926-860x(95)00077-1 https://onlinelibrary.wiley.com/doi/10.1002/er.4995 https://onlinelibrary.wiley.com/doi/10.1002/er.4995 https://onlinelibrary.wiley.com/doi/10.1002/er.4995 https://onlinelibrary.wiley.com/doi/10.1002/er.4995 https://mediatum.ub.tum.de/601363 https://mediatum.ub.tum.de/601363 https://mediatum.ub.tum.de/601363 https://mediatum.ub.tum.de/601363 https://www.sciencedirect.com/science/article/abs/pii/s0016236119319209 https://www.sciencedirect.com/science/article/abs/pii/s0016236119319209 https://www.sciencedirect.com/science/article/abs/pii/s0016236119319209 https://doi.org/10.1016/j.mcat.2018.02.003 https://doi.org/10.1016/j.mcat.2018.02.003 https://doi.org/10.1016/j.mcat.2018.02.003 https://doi.org/10.1016/j.mcat.2018.02.003 https://doi.org/10.1016/j.proeng.2015.07.291 https://doi.org/10.1016/j.proeng.2015.07.291 https://doi.org/10.1016/j.proeng.2015.07.291 https://doi.org/10.1016/j.proeng.2015.07.291 https://doi.org/10.1016/j.proeng.2015.07.291 https://www.scientific.net/msf.1039.313 https://www.scientific.net/msf.1039.313 https://www.scientific.net/msf.1039.313 https://www.scientific.net/msf.1039.313 https://doi.org/10.1063/1.5122022 https://doi.org/10.1063/1.5122022 https://doi.org/10.1063/1.5122022 https://doi.org/10.1063/1.5122022 https://doi.org/10.1063/1.5122022 https://doi.org/10.1063/1.5122022 https://www.sciencedirect.com/science/article/abs/pii/s0920586118312197 https://www.sciencedirect.com/science/article/abs/pii/s0920586118312197 https://www.sciencedirect.com/science/article/abs/pii/s0920586118312197 https://www.sciencedirect.com/science/article/abs/pii/s0920586118312197 s. a. kamel et al. / iraqi journal of chemical and petroleum engineering 22,4 (2021) 1 10 9 [16] hauli, l., wijaya, k., armunanto, r., (2018). "preparation and characterization of sulfated zirconia from a commercial zirconia nanopowder". orient. j. chem. 34, 1559–1564. [17] aboul-gheit, a.k., el-desouki, d.s., abdelhamid, s.m., ghoneim, s.a., ibrahim, a.h., gad, f.k., 2012. sulfated zirconia catalysts for low temperature isomerization of n-pentane. egypt. j. chem. 55, 509–527. [18] m. bustol .a.dossoc.r.veraj.m.grau ,(2012) , composite catalysts of pt/so42−–zro2 and pt/wo3– zro2 for producing high octane isomerizate by isomerization-cracking of long paraffins, fuel processing technology volume 104, december 2012, pages 128-135. [19] torres, g.c., manuale, d.l., benítez, v.m., román, c., carlos, j., 2012. modification of the performance of wo3-zro2 catalysts by metal addition in hydrocarbon reactio artigo 35, 748–754. [20] hsu c.y., heimbuch c.r., armes c.t. , gates b.c., (1992)," a highly active solid superacid catalyst for n-butane isomerization: a sulfated oxide containing iron, manganese and zirconium", j. chem. soc. chem. commun, 22,p.p. 1645-1646. [21] sadoon ahmedzeki, n., & salah alddin mahdi, a. (2014). research octane number improvement of iraqi gasoline by adsorption of n-paraffins using zeolite molecular sieves. iraqi journal of chemical and petroleum engineering, 15(2), 27-37. [22] singhal, s., agarwal, s., kumar, a., 2019. isomerization of lighter alkanes by heteropoly acids : a review. j. catal. catal. 2, 1–14. https://doi.org/10.13005/ojc/340348 https://doi.org/10.13005/ojc/340348 https://doi.org/10.13005/ojc/340348 https://doi.org/10.13005/ojc/340348 https://doi.org/10.21608/ejchem.2012.1171 https://doi.org/10.21608/ejchem.2012.1171 https://doi.org/10.21608/ejchem.2012.1171 https://doi.org/10.21608/ejchem.2012.1171 https://doi.org/10.21608/ejchem.2012.1171 https://www.sciencedirect.com/science/article/pii/s0378382012001695 https://www.sciencedirect.com/science/article/pii/s0378382012001695 https://www.sciencedirect.com/science/article/pii/s0378382012001695 https://www.sciencedirect.com/science/article/pii/s0378382012001695 https://www.sciencedirect.com/science/article/pii/s0378382012001695 https://www.sciencedirect.com/science/article/pii/s0378382012001695 https://www.scielo.br/j/qn/a/gfhd3dlnrczfpfwlhwx6twl/?lang=en https://www.scielo.br/j/qn/a/gfhd3dlnrczfpfwlhwx6twl/?lang=en https://www.scielo.br/j/qn/a/gfhd3dlnrczfpfwlhwx6twl/?lang=en https://www.scielo.br/j/qn/a/gfhd3dlnrczfpfwlhwx6twl/?lang=en https://www.scielo.br/j/qn/a/gfhd3dlnrczfpfwlhwx6twl/?lang=en https://pubs.rsc.org/en/content/articlelanding/1992/c3/c39920001645/unauth https://pubs.rsc.org/en/content/articlelanding/1992/c3/c39920001645/unauth https://pubs.rsc.org/en/content/articlelanding/1992/c3/c39920001645/unauth https://pubs.rsc.org/en/content/articlelanding/1992/c3/c39920001645/unauth https://pubs.rsc.org/en/content/articlelanding/1992/c3/c39920001645/unauth https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/275 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/275 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/275 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/275 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/275 https://www.researchgate.net/profile/amit-kumar-291/publication/332171149_journal_of_catalyst_catalysis_isomerization_of_lighter_alkanes_by_heteropoly_acids_a_review/links/5ca45990a6fdcc12ee8eeee2/journal-of-catalyst-catalysis-isomerization-of-lighter-alkanes-by-heteropoly-acids-a-review.pdf https://www.researchgate.net/profile/amit-kumar-291/publication/332171149_journal_of_catalyst_catalysis_isomerization_of_lighter_alkanes_by_heteropoly_acids_a_review/links/5ca45990a6fdcc12ee8eeee2/journal-of-catalyst-catalysis-isomerization-of-lighter-alkanes-by-heteropoly-acids-a-review.pdf https://www.researchgate.net/profile/amit-kumar-291/publication/332171149_journal_of_catalyst_catalysis_isomerization_of_lighter_alkanes_by_heteropoly_acids_a_review/links/5ca45990a6fdcc12ee8eeee2/journal-of-catalyst-catalysis-isomerization-of-lighter-alkanes-by-heteropoly-acids-a-review.pdf s. a. kamel et al. / iraqi journal of chemical and petroleum engineering 22,4 (2021) 1 10 10 تصنيع وتشخيص العامل المساعد النانوي الزركونيا المكبرتة المحملة بالنيكل واوكسيد التنكستن الزمرة الهكسان والنفثا العراقية الخفيفة حيدر عبد الكريم رشيد و صفا عبد السالم كامل , ودود طاهر محمد جامعة بغداد/ كلية الهندسة الخالصة ( الزمرة الهكسان والنفثا الخفيفة و تطويرهما , باالضافة الى التدعيم szتم تحضيرمحفز الزركونيا المكبرتة ) ببعض المعادن للحصول على الظروف المعتدلة واالستقرارية ومنع تكون الفحم على المواقع الحامضية في تم توصيف جميع محفزات التقليدية والمعدلة بواسطة التحليل الطيفي لالشعة تحت الحمراء العامل المساعد. ftir االشعة السينية ,xrd ,brunauer -emmett-teller (bet) تحليل المساحة السطحية , ل . اظهرت النتائج أن الحد األقصى للتحوي afm, تحليل الذري المجهري tgaالتحلل الحراري الوزني % على التوالي. اما باقي 96% و 80,1م هي °150بدرجة حرارة ni-wszواإلنتاجية ألزمرة الهكسان على وفي ni-wszالتجارب مع النفثا الخفيفة فقد اظهرت ان اعلى نسبة تحول واالنتاجية على االلعامل المساعد % على التوالي.74% و 53م هي °150درجة حرارة تنكستن, االزمرة , الزركونيا المكبرتة-: النفثا الخفيفة, الهكسان, نيكل الدالةالكلمات iraqi journal of chemical and petroleum engineering vol.15 no.1 (march 2014) 5157 issn: 1997-4884 apparent viscosity direct from marsh funnel test faleh h. m. almahdawi, ahmed zarzor al-yaseri and nagham jasim petroleum engineering department – college of engineeringuniversity of baghdad-iraq abstract accurate and simple techniques for measurement of fluid rheological properties are important for field operations in the oil industry. marsh funnels are popular qualitycontrol tools used in the field for drilling fluids and they offer a simple, practical alternative to viscosity measurement. in the normal measurements, a single point (drainage time) is used to determine an average viscosity; little additional information is extracted regarding the non-newtonian behavior of the fluid. here, a new model is developed and used to determine the rheological properties of drilling muds and other non-newtonian fluids using data of fluid density and drainage time collected from a marsh funnel as a function of viscosity. the funnel results for viscosity compare favorably to the values obtained from a commonly-used fann 35 viscometer. different quantities of bentonite, barite and other additives which have been used to prepare many samples. empirical equations are obtained µapp. = ρ (t – 28) and µapp. = -0.0118t2 + 1.6175t 32.168, where apparent viscosity (µapp.) in (cp), marsh funnel time (t) in seconds and the density (ρ) in gm/cm3. introduction hydrocarbon production uses many fluids that are rheologically complex. among these is cement, drilling muds, aqueous solutions of water-soluble polymer and of course crude oil itself. drilling fluids can be air or water, but most commonly they are “muds” or suspensions of solids in an aqueous or oleic fluid. the solids are suspended with one or more surfactants. the solids are used to provide weight to the mud for pressure control, the main function of muds, but muds also lubricate the drill, carry drilling cuttings to the surface and cool the bit. most muds are water-based as is the type used in this study. when fresh water is the liquid base, bentonite is the clay used for its superior properties necessary to achieve the goals stated for drilling mud [1]. water-based fluids are suspensions of weight material in water, but also contain a number of additives to control fluid properties such as rheology, fluid loss, shale inhibition and lubricity. the standard weight material is api barite. there are also non-standard weight materials with considerably finer particle size, which generate low rheology and are used in some highdensity and/or slim-hole applications. the liquid phase of drilling fluids generally contains a number of additives to control the various required properties of fluids, including one or more rheology additives to iraqi journal of chemical and petroleum engineering university of baghdad college of engineering apparent viscosity direct from marsh funnel test 52 ijcpe vol.15 no.1 (march 2014) -available online at: www.iasj.net suspend the weight material. thus, fluid rheology is generated partly by the suspended solids and partly by the rheology additives [2, 3]. drilling mud exhibits several important rheological properties [4]. the viscosity or consistency index of a mud is a measure of flow resistance. therefore viscosity should be as small as possible to limit friction pressure. however a certain amount of viscosity is required to improve the solids carrying capacity of the mud. if viscosity is too small, the mud may be unable to suspend drilled solids at the desired pump rate. this requires the pumps to be run faster to continue to circulate drilled solids out of the well. if viscosity is too high, an excessive pump pressure will be required to circulate the mud at the desired rate. higher than necessary pump pressure is an added strain on the pumps and piping and an added pressure in the bore hole that can lead to well bore stability problems. nonnewtonian fluids (drilling muds and polymers) may also exhibit a yield stress (or gel strength). for drilling operations, the higher the yield stress the more pump pressure will be required to initiate circulation. the yield stress can also be a desirable property because it will suspend the drilled solids and prevent or slow them from slipping back to the bottom of the hole during periods when there is no circulation. fluid yield stress in fracturing fluids for example can help carry and suspend proppant, but can also make cleanup difficult [5]. below the yield stress the material is solidlike and has an infinite viscosity. the solid-like behavior is typically a result of a three-dimensional microstructure at low stresses [6]. above the yield stress the material deforms as a fluid and the viscosity is a function of shear rate. many pastes, foodstuffs, gels, and drilling muds have a yield stress. the simplest yield-stress model is the bingham model, in which the relationship between shear stress and shear rate is linear, with the yield stress defined as the extrapolated y-axis intercept [2]. marsh funnel the marsh funnel was invented by hallan n. marsh in 1931 [7]. it is used to measure the time in seconds required to fill a set volume of fluid. (in the united states the volume is one quart.) the flow through the small tip at the end of the funnel is related to the rheological properties of the fluid being measured. the marsh funnel “viscosity” is reported as seconds and used as an indicator of the relative consistency of fluids. the more viscous the fluid the longer the time to fill one quart. the calibration for marsh funnel time is 28 seconds per quart for fresh water. the standard marsh funnel is shown in fig. 1 . the marsh funnel provides a simple and effective tool to determine the relative viscosity of drilling mud. here, we also use the funnel for additional oilfield fluids. fig. 1, standard marsh funnel figure 1 shows that the height of coneportion of the funnel is 12 in. http://www.sciencedirect.com.tiger.sempertool.dk/science/article/pii/s092041051100088x#bb0060 http://www.sciencedirect.com.tiger.sempertool.dk/science/article/pii/s092041051100088x#bb0025 http://www.sciencedirect.com.tiger.sempertool.dk/science/article/pii/s092041051100088x#bb0055 http://www.sciencedirect.com.tiger.sempertool.dk/science/article/pii/s092041051100088x#f0005 faleh h. m. almahdawi, ahmed zarzor al-yaseri and nagham jasim -available online at: www.iasj.net ijcpe vol.15 no.1 (march 2014) 53 (30.5 cm) and the diameter is 6 in. (15.2 cm). the copper tubing is 2 in. (5.08 cm) in length and has a diameter of 3/ in. (0.48 cm). although rheological properties of these fluids can be measured by conventional rheometers, a simple method is often needed. the goal of this work is to develop such a method for determining rheological properties of non-newtonian fluids using a marsh funnel. an experiment consists of filling the funnel to a pre-specified height and measuring the rate at which the test fluid drains. the flow behaviour of a marsh funnels is simulated numerically [8]. as a result, his simulation provides a general picture of the meaning of the marsh funnel time and a correlation enabling this to be converted into a value for effective viscosity of nonnewtonian fluids. the final equation for m.j. pitt is: µeff. = ρ (t – 25) …(1) where: µeff. = effective viscosity (cp); ρ= density (gm/cc); t=time (sec.) the model presented in this work can estimate the apparent viscosity instead of effective viscosity depends on pitt’s equation in this study we used experimental data instead of numerical simulation. fluid preparation many of the fluids used in these experiments must be mixed before testing. the used fluids are waterbased fluids. before adding any solid particles or polymer to the water-based fluids used here, water was adjusted to approximately a ph of 9 by adding droplets of naoh (sodium hydroxide). for all tests, the fluid was at room temperature (~ 30 °c), the density was measured using a density balance, and the rheology measured using a fann v. g. 35 viscometer. fluid was then poured in the marsh funnel for the tests. different quantities of bentonite, barite and other additives which have been used to prepare samples and the measured values are listed in table 1. marsh funnel test after the fluid rheology is measured, the fluid is placed in the marsh funnel as shown in table 1. the marsh funnel is designed so that 1500 ml of fluid can be poured into the funnel. a small stopper is placed in the orifice at the bottom to prevent flow out while the fluid is poured into the funnel. once it reaches the bottom of the screen, this indicates that 1500 ml now rests in the funnel. the purpose of screening is to remove any unmixed solid particles from the rest fluid. results and discussion after measuring the fluid properties from lab., an experimental correlation between the apparent viscosity and marsh time is estimated as: µapp.=-0.0118t 2 +1.6175t -32.168 …(2) as shown in fig. 2. also, we investigated that the apparent viscosity is equal to µapp. = ρ (t – 28) …(3) depend on marsh time and density together as shown in fig. 3. table 2 shows the results of viscosity which show all calculations to determine the viscosity from observed equations. in addition, the accuracy of the present work compared to the true data. apparent viscosity direct from marsh funnel test 54 ijcpe vol.15 no.1 (march 2014) -available online at: www.iasj.net table 1, fluid properties from lab no. marsh time (second) density (gm/cm 3 ) app viscosity from lab. (true value); cp 1 40.15 1.025 11.5 2 36.8 1.032 10 3 35.14 1.045 10 4 34.58 1.05 10.25 5 34 1.053 10.75 6 44.6 1.03 15 7 44.4 1.04 15 8 43.21 1.05 15 9 42.03 1.05 15.25 10 40.9 1.051 15.75 11 55 1.03 20.5 12 55.6 1.035 20 13 49.88 1.04 20.5 14 49.13 1.047 21 15 49 1.049 21 16 45 1.02 14.5 17 40 1.035 11.5 18 39 1.04 10.5 19 38 1.053 11 20 36.2 1.06 11 21 36 1.1 10 22 36.2 1.1 10.5 23 45 1.035 22.5 24 46.76 1.043 17.5 25 42.08 1.06 15 26 39.63 1.079 13 27 38.53 1.098 11.5 28 38 1.15 10.5 29 59.11 1.03 19.5 30 43.78 1.035 15.5 31 41.67 1.055 15 32 40.79 1.08 13.5 33 39.78 1.09 13.5 34 38 1.11 12.5 fig. 2, the relationship between true app. viscosity (cp) vs. marsh funnel time(sec.) faleh h. m. almahdawi, ahmed zarzor al-yaseri and nagham jasim -available online at: www.iasj.net ijcpe vol.15 no.1 (march 2014) 55 fig. 3, the relationship between true app. viscosity (cp) vs.. µapp from equation (3) table 2, apparent viscosity calculations n marsh time density app viscosity from lab vis.= den. (t-28) app. viscosity from time only vis.= den. (t-25) 1 40.15 1.025 11.5 12.45375 12.96296666 15.52875 2 36.8 1.032 10 9.0816 11.20376633 12.1776 3 35.14 1.045 10 7.4613 10.37067288 10.5963 4 34.58 1.05 10.25 6.909 10.09549982 10.059 5 34 1.053 10.75 6.318 9.813648558 9.477 6 44.6 1.03 15 17.098 15.45686264 20.188 7 44.4 1.04 15 17.056 15.34100763 20.176 8 43.21 1.05 15 15.9705 14.65894974 19.1205 9 42.03 1.05 15.25 14.7315 13.99500999 17.8815 10 40.9 1.051 15.75 13.5579 13.37086832 16.7109 11 55 1.03 20.5 27.81 21.95340737 30.9 12 55.6 1.035 20 28.566 22.35578865 31.671 13 49.88 1.04 20.5 22.7552 18.64076205 25.8752 14 49.13 1.047 21 22.12311 18.17394784 25.26411 15 49 1.049 21 22.029 18.09351863 25.176 16 45 1.02 14.5 17.34 15.68962422 20.4 17 40 1.035 11.5 12.42 12.88199777 15.525 18 39 1.04 10.5 11.44 12.34744062 14.56 19 38 1.053 11 10.53 11.822043 13.689 20 36.2 1.06 11 8.692 10.89965975 11.872 21 36 1.1 10 8.8 10.79904076 12.1 22 36.2 1.1 10.5 9.02 10.89965975 12.32 23 45 1.035 22.5 17.595 15.68962422 20.7 24 46.76 1.043 17.5 19.56668 16.73033785 22.69568 25 42.08 1.06 15 14.9248 14.02289131 18.1048 26 39.63 1.079 13 12.54877 12.6831489 15.78577 27 38.53 1.098 11.5 11.56194 12.09935823 14.85594 28 38 1.15 10.5 11.5 11.822043 14.95 29 59.11 1.03 19.5 32.0433 24.76824529 35.1333 30 43.78 1.035 15.5 16.3323 14.98409134 19.4373 31 41.67 1.055 15 14.42185 13.79492469 17.58685 32 40.79 1.08 13.5 13.8132 13.31072456 17.0532 33 39.78 1.09 13.5 12.8402 12.76361318 16.1102 34 38 1.11 12.5 11.1 11.822043 14.43 apparent viscosity direct from marsh funnel test 56 ijcpe vol.15 no.1 (march 2014) -available online at: www.iasj.net fig. 4, app. viscosity from different methods conclusions: a clear relationship between the marsh funnel viscosity (t) and the apparent viscosity was obtained through this study, as well as, an equation correlating the apparent viscosity to both density and marsh funnel viscosity (t) is presented. the comparison between the obtained equation 3 and the equation given by m. j. pitt equation 1 show that constant (28) is more accurate and appropriate than constant (25) given by the same author. (see table 2) figure 4 shows that the relationship no. 2 is more accurate and it can be recommended for use as a relationship between the apparent viscosity measured from the device (multi speed viscometer) and the viscosity values measured as time from marsh funnel. (see table 2) references 1matthew t. balhoff and et. al. "rheological and yield stress measurements of nonnewtonian fluids using a marsh funnel", journal of petroleum science and engineering,june, 2011 v.77 pp.393-402. 2ahmadi tehrani, behaviour of suspensions and emulsions in drilling fluids. annual transactions http://www.sciencedirect.com.tiger.sempertool.dk/science/article/pii/s092041051100088x http://www.sciencedirect.com.tiger.sempertool.dk/science/journal/09204105 http://www.sciencedirect.com.tiger.sempertool.dk/science/journal/09204105 faleh h. m. almahdawi, ahmed zarzor al-yaseri and nagham jasim -available online at: www.iasj.net ijcpe vol.15 no.1 (march 2014) 57 of the nordic rheology society, vol. 15, 2007. 3power, d. and zamora, m. (2003), “drilling fluid yield stress: measurement techniques for improved understanding of critical drilling fluid parameters”, aade03-ntce-35, aade technical conference, houston, apr. 1-3. 4a.t. bourgoyne jr., m.e. chenevert, k.k. millheim, f.s. young jr. applied drilling engineering, spe textbook series, vol. 2society of petroleum engineers, richardson, tx (1991). 5e.a. may, l.k. britt, k.g. nolte,the effect of yield stress on fracture fluid cleanup spe 38619, presented at the 1997 society of petroleum engineers annual technical conference and exhibition in san antonio, texas (1997). 6p.j. carreau, d.c.r. de kee, r.p. chhabra,rheology of polymeric systems hanser/gardner publications, inc., cincinatti (1997). 7h. marsh, properties and treatment of rotary mud .petroleum development and technology, transactions of the aime (1931), pp. 234–251. 8m.j. pitt,the marsh funnel and drilling fluid viscosity: a new equation for field use.soc. petroleum eng., drilling completions, 15 (1) (2000), pp.3–6. iraqi journal of chemical and petroleum engineering vol.14 no.3 (september 2013) 5562 issn: 1997-4884 removal of phenolic compounds from aqueous solution by using agricultural waste (al-khriet) hayder a.k. al-jandeel chemical engineering department, college of engineering, university of baghdad abstract adsorption techniques are widely used to remove organics pollutants from waste water particularly, when using low cost adsorbent available in iraq. al-khriet powder which was found in legs of typha domingensis is used as bio sorbent for removing phenolic compounds from aqueous solution. the influence of adsorbent dosage and contact time on removal percentage and adsorb ate amount of phenol and 4nitro phenol onto al-khriet were studied. the highest adsorption capacity was for 4nitrophenol 91.5% than for phenol 82% with 50 mg/l concentration, 0.5 gm. dosage of adsorbent and ph 6 under a batch condition. the experimental data were tested using different isotherm models. the results show that freundlich model resulted in the best fit also the kinetic study make it clear that the adsorption process proceeded according to the pseudo second order model. key words: al-khriet, agricultural waste adsorbent, bio sorption, phenolic compound, isotherm kinetic model introduction phenols and their derivatives are known to be highly toxic for human beings and the aquatic life [1]. they result from different industrial processes such as, synthetic rubber, petrochemical industry, plastics, coking, paper, phenolic resin industries, and oil refineries [2, 3]. the use of water contained phenol can result in retardation of the central nervous system (cns), impairment of the liver, kidney and irritation of the eyes, skin and mucous membrane [4]. it had been concluded from earlier studies that the skin is a route of entrance of phenol [5]. a 32 years old man died soon after spilling strong solution of phenol above his shoulder and other part of his body. chronic phenol poisoning is diagnosed by the disfunction of different body system such as the nervous system. the human eyes is very sensitive to the chemical especially the phenol causing swelling and burns as well as the cornea may become white or even loosen sensation. loss of vision has happened in some case [6]. according to the world health organization (who), the recommended concentration of phenolic compound in drink water is 1 mg/l [7] and that is why it is strongly recommended to remove phenolic compounds from wastewater. for this reason different environment friendly process had been used. several physicochemical and biological treatment techniques such as chemical oxidation [8], ultrasonic iraqi journal of chemical and petroleum engineering university of baghdad college of engineering removal of phenolic compounds from aqueous solution by using agricultural waste (al-khriet) 56 ijcpe vol.14 no.3 (september 2013) -available online at: www.iasj.net degradation [9], photo catalytic degradation using son photo chemical [10], enzymatic polymerization [11], ion exchange by resin [2] and adsorption [12] but the most efficient process and economically feasible technology for removal phenol in adsorption, especially when using locally available adsorbent. many research have studied the feasibility of inexpensive adsorbents such as alkhriet, (a powder which has been found in the legs of typa domingensis) agricultural waste and it is easily available in the waste could be an alternative for cheaper raw materials that are used to treat waste water. according to the literature there is no present study on the biosorptive removal of phenolic compound from aqueous solution using al-khriet. , they were selected for this research because they represent commonly encountrated phenolic pollutants in waste water treatment. the aim of this study is to look closely into the adsorption of al-khriet for removing phenol and 4-nitrophenol from aqueous solution. the effect of various factors, such as time of contact, bio sorbent dosage and initial adsorbent concentration on the adsorption process is investigated under batch experiments. kinetic and equilibrium models were used to fit experimental data. material and adsorbent properties al-khriet, a powder was collected from the marshes in the south of iraq, first it was washed with dionized water several times to remove impurities and dried in air for two days before drying in oven at 100°cover night finally alkhriet powder was stored in dictator. experimental work different concentrations of phenol and 4-nitrophenol aqueous solution were prepared from stock of 500 mg/l by dissolving a proper amount of phenol and 4-nitrophenol in deionized water. the properties of phenol and 4nitrophenol are shown in table 1. another reason for choosing these compounds is their difference in molecular structure; phenol is two dimensional, flat structures, while 4nitrophenol is three dimensional. table 1, physical properties of adsorbents [13] adsorb ate phenol 4-nitrophenol molecular weight (g/mol.) 94.1 139.1 water solubility (g/ lh2o) 93 17 molecular dimensions, (a 0 ) 5.76*4.17 6.84*4.17 adsorption was performed in a batch mode. the equilibrium isotherm was determined by mixing 0.5 gm of alkhriet with 25 ml of phenol and 4nitrophenol solution with different initial concentration (50-200) mg/l in conical flask. the flask was shaken in shaker at room temperature of 25°c for 3 hrs. such a time is indeed to reach equilibrium according to series of experiments. the suspension of alkhriet was then filtered and the residual phenol concentration was measured by uv-visible (shimadzu uv160a) spectrophotometer. the latter was calibrated at a wavelength of 270 nm, 320 nm for phenol and 4nitrophenol respectively using a number of aqueous solutions of phenol and 4-nitrophenol at known concentration in order to calculate the calibration curve. the adsorbed amount at equilibrium, e q (mg/g) and removal percentage of phenol and 4-nitrophenol onto alkhriet were calculated according to the following equation [14]. w vcc q e e )( 0   … (1) 100*% 0 0 c cc r e   … (2) hayder a.k. al-jandeel -available online at: www.iasj.net ijcpe vol.14 no.3 (september 2013) 57 where r is the removal percentage, 0 c and e c are the initial and equilibrium concentrations of adsorb ate (mg/l) respectively, v is the volume of solution (l), w is the weight of adsorbent used (gm.). the adsorption kinetics was analyzed by adding 0.5gm of al-khriet to 25 ml of 50 mg/l of phenol and 4nitrophenol solutions. the sample was shaken and examined at different time intervals. the effect of adsorbent dosage and the initial concentration of feed solution were also studied by using different amount of adsorbent (0.2-1) gm for the 50 mg/l solution of phenol and 4-nitrophenol. results and discussion effect of contact time as shown in fig.1 the percent removal of phenol and 4-nitrophenol by adsorption onto al-khriet increases with contact time until attain equilibrium of about 3 hr. removal percent equal to 91.5% and 82% for 4nitrophenol and phenol respectively at ph 6 and of 50 ppm ions concentration for each adsorb ate and 0.5 gm. of adsorbents. the result indicates that the rate of sorption of 4-nitrophenol and phenol on al-khriet were fast because of a largest amount of two compounds attached to the adsorbent within 1 hr of adsorption. the similar results have been reported by khorsravi r. et al [15]. fig.1 effect of time on removal efficiency using al-khriet as adsorbent the effect of adsorbent dosage the adsorption of phenol and 4nitrophenol on al-khriet was carried out by various adsorbent dosages. the relationship between adsorbent dosage and percent of removal is presented in fig.2. it can be perceived the percent of removal increased with increasing of al-khriet dosage while the loading capacity e q (mg/g) decreased, this is due to increase surface area, more adsorption sites are available. the optimum weight of adsorbents was found (0.5) gm. for al-khriet. fig.2 effect of adsorbent dosage on percent removal for phenol and 4-nitrophenol by alkhriet, contact time 3 hr. initial concentration for both ions 50 ppm it is appears from this figure that the removal percent of 4-nitrophenol is higher than phenol that is due to its lower water solubility and larger molecular weight of 4-nitrophenol when compared to phenol according to table 1. in general, the adsorptive capacity was related to the electron with drawing or electrondonating functional groups, water solubility of the compound and the molecular structure of the adsorb ate. the less soluble compounds are easier to be adsorbed [2]. effect of phenol and 4-nitrophenol concentration the effect of phenol and 4nitorphenol concentration on percent of removal was studied. the 0 20 40 60 80 100 0 50 100 150 200 250 tim e(m in) r % 4-nitrophenol phenol 60 70 80 90 100 0.2 0.5 0.75 1 adsorbent dosage (gm) r e m o v a l p e r c e n t 0 1 2 3 4 5 l o a d in g c a p a c it y q e 4-nitrophenol phenol 4-nitrophenol phenol removal of phenolic compounds from aqueous solution by using agricultural waste (al-khriet) 58 ijcpe vol.14 no.3 (september 2013) -available online at: www.iasj.net concentration was varied from (50200) ppm on 0.5 gm. of al-khriet at room temperature. the result in fig. 3 shows that the percent removal decreased as the concentration of phenol and 4-nitorphenol increased, indicating the less favorable sites and available for adsorb ate with increasing concentration. removal percent equal to 85 % and 74% for 4-nitrophenol and phenol respectively at 200 ppm concentration, using 0.5gm of alkhriet and ph of 6. the ph value were 6 before and after mixing with adsorbent. 0.1m of naoh and hcl were used for ph adjustment to fix the ph value in all experiments. fig.3 removal of phenol and 4nitro phenol using different concentration of ions kinetic studies different kinetic models including the pseudo first order model (pfom) and pseudo second order model (psom) were examined for the experimental data to estimate the adsorption kinetics. the pfom and psom may be represented by the following equations respectively [16]. tkqqq ete 1 ln)ln(  … (3) eet q t qkq t  2 2 1 … (4) where e q , t q is the amount of adsorbed at equilibrium (mg.g -1 ), 1 k and 2 k is the rate constant for pfom and psom respectively. the slope and intercept of plots )ln( te qq  versus time were used to determine the 1 k while the slope and intercept of plot of t q t versus t were used to calculate 2 k . the pfom and psom plots are shown in fig. 4 and fig. 5 respectively. a comparison of kinetics model is included in table 2, based on their correlation coefficient (r 2 ). the adsorption of phenolic compounds onto al-khriet is suitable for psom, based on higher correlation coefficients. fig.4 pfom plots for phenol and 4nitrophenol fig.5 psom plots for phenol and 4nitrophenol 0 10 20 30 40 50 60 70 80 90 100 0 50 100 150 200 250 ppm r % 4-nitophenol phenol -4.5 -4 -3.5 -3 -2.5 -2 -1.5 -1 -0.5 0 0 50 100 150 200 tim e ln ( q e q t) 4-nitrophenol phenol 0 10 20 30 40 50 60 70 80 90 100 0 50 100 150 200 tim e(m in) t /q t 4-nitrophenol phenol hayder a.k. al-jandeel -available online at: www.iasj.net ijcpe vol.14 no.3 (september 2013) 59 table 2, the rate constant and correlation coefficient for pseudo first and second order for the kinetic models kinetic model parameters nitrophenol phenol pfom k1(min -1 ) 0.022 0.016 eq (mg/g) 0.733 0.613 r1 2 0.926 0.94 psom k2 (mg.g -1 . min -1 ) 0.055 0.048 eq (mg/g) 2.37 2.14 r1 2 0.999 0.998 equilibrium isotherms langmuir (lm), freundlich (fu) and dubinin-rodushkevich (d-ru) were chosen in this study to assess the relationship between the equilibrium concentration and the amount of phenol and 4-nitrophenol adsorbed on al-khriet. the lm assumes that the adsorption occurs at specific homogenous sites within the adsorbent and has found successful application in many studies of monolayer adsorption. the lm equation is given by the following equation [17]. maxmax 1 q c kqq c e le e  … (5) where e q is the solid phase adsorbate concentration in equilibrium (mg/g), max q the maximum adsorption capacity corresponding to complete monolayer coverage (mg/g), e c the concentration of adsorb ate at equilibrium (mg/l) and l k is the langmuir constant l/mg. the l k and max q can be evaluated from the slopes and intercept of linear plots ee qc / versus e c as shown in fig. 6, the parameter of these model were tabulated in table (3). fig.6, adsorption isotherm of phenol and 4nitrophenol at ph (6) by using langmuir table 3, parameter of isotherms for phenol and 4-nitrophenol and correlation coefficient for langmuir isotherm r 2 kinetic model parameters 4nitrophenol phenol langmuir max q (mg/g) 15.24 16.6 l k l/mg 0.0.039 0.015 r 2 0.979 0.99 freundlich model is present by following equation [18]. efe c n kq ln 1 lnln  … (6) freundlich describes the adsorption on an energetically heterogeneous surface on which the adsorbed molecules are interactive. this isotherm dose not predict any saturation of the sorbent by sorbate, indicating multilayer sorption where f k is the freundlich constant (mole/gm.) and n stands for the adsorption intensity. the value of f k and 1/n were calculated from slope and intercept of the plot between e qln and e cln as shown in fig. 7. the value of f k and n were tabulated in table (4). r 2 = 0.99 r 2 = 0.9787 0 1 2 3 4 5 6 7 8 0 10 20 30 40 50 60 ce c e / q e 4-nitrophenol phenol removal of phenolic compounds from aqueous solution by using agricultural waste (al-khriet) 60 ijcpe vol.14 no.3 (september 2013) -available online at: www.iasj.net fig.7 adsorption isotherm of phenol and 4nitrophenol at ph (6) by using freundlich table 4, parameter of isotherms for phenol and 4-nitrophenol and correlation coefficient for freundlich isotherm r2 kinetic model parameters 4nitrophenol phenol freundlich n f mg l g mg k 1 )( 0.886 0.414 n 1.50 1.36 r 2 0.998 0.999 the dubinin-rodushkevich model is an empirical equation employed to determine if the adsorption occurred by a physical or chemical process. the dubinin-rodushkevich[19] equation is more general than langmuir because it does not assume a homogenous surface or a constant sorption potential. the linear form of this model is represented by 2 lnln bqq me  … (7) b ( 22 .  kjmol ) is the constant related to sorption energy while  is the polanyi sorption potential. ) 1 1ln( e c rt  … (8) r is the gas constant 8.314 j.mol -1 k -1 , t is the temperature in kelvin. the value of b, m q were calculated from the slopes and intercept of the plots e qln versus 2  as shown in fig. 8 and 9 [19], the parameter of these models were tabulated in table (5). fig.8 adsorption isotherm of 4-nitrophenol at ph (6) by using dubinin-rodushkevich fig.9 adsorption isotherm of phenol at ph (6) by using dubinin-rodushkevich table (5) parameter of isotherms for phenol and 4-nitrophenol and correlation coefficient for dubinin-rodushkevich isotherm r 2 kinetic model parameters 4nitrophenol phenol dubininrodushkevich b* 4 10 0.04 3 m q m q 7 147.7 r 2 0.886 0.998 the experimental data yielded excellent fit within the following isotherm fu>lm> d-ru based on its 2 r value as it gave the maximum 2 r value among the conceded model. r 2 = 0.9982 r 2 = 0.9991 0 0.5 1 1.5 2 2.5 0 1 2 3 4 5 ln(ce) ln ( q e ) 4-nitrophenol phenol 0 0.5 1 1.5 2 2.5 0 50000 100000 150000 200000 250000 300000 ln ( q e ) 4-nitrophenol 0 0.5 1 1.5 2 2.5 0 5000 10000 15000 ln (q e ) phenol hayder a.k. al-jandeel -available online at: www.iasj.net ijcpe vol.14 no.3 (september 2013) 61 conclusion al-khriet can be used for first time as effective, locally available adsorbents for the removal of phenol and nitrophenol from waste water. the adsorption of phenol and nitrophenol on al-khriet is dependent on contact time, initial concentration and adsorbent dosage. it was observed that the removal process increase with contact time and attain equilibrium about 180 minute. in the study of kinetics of adsorption, the pseudo second order mode provides better correlation than pseudo first order model. also freundlich model was found to fit the present experimental data with high correlation factor. finally al-khriet under consideration is not only economical, but also an agriculture waste and locally available which would be useful for economical treatment of waste water containing phenol compounds. references 1mahamad m.ayad, ahmed abu elnasr, jaroslav stejskal, 2012, kinetics of methylene blue adsorption onto polyaniline nanotubes base/ silica composite, journal of industrial and engineering chemistry. http://dx.doi.org/101016/j.jiec.2012.05.012. 2nada vila, siva kumar and kim min, 2011, removal of phenolic compounds from aqueous solution biosorption onto acetic acid leucocephala bark powder; equilibrium and kinetic. j.chil. chem.soc. vol.56, no.1. 3gupta v.k., s., sharma i.s. yadav, d.mohn. 1998, utilization of bagasse fly ash generated in the sugar industry for the removal and recovery of phenol and pnitrophenol from waste water. j.chem.technol. biotechnol.,71,pp. 180-186. 4spandre r., dellonaco g-, 1996, polyphenol pollution by olive mill waste waters, tuscany, italy, j.environ.hydrol., 4, pp. 1-13. 5atsdr (agency for toxic substances and disease registry), 1998, toxicological profile for phenol, us department of health and human services, usa. 6hofman m. and pietrzak r., 2012, nitrogen-doped carbonaceous materials for removal of phenol from aqueous solutions. the scientific world journal, v.2012, article id 297654, 8 pages, doi: 10. 1100/2012/297654. 7anirudhan t.s.. sreekumari s.s., bringle c.d., 2009, removal of phenols from water and petroleum industry refinery effluents by activated carbon obtained from coconut coir pith adsorption. pp. 439-451. 8leyva e., moctezuma e., ruiz m.g., torresmatinez l. 1998, photo-degradation of phenol by bao.li2o-tio2 catalysts, catal,today, 40,pp.367-376. 9a.b. pandit, p.r, gogate, mujumdar s., 2001, ultrasonic degradation at 2:4:6 trichlorophenol in present of tio2 catalyst, ultrson, sonochem, 8, pp. 227-231. 10shirgonkar i.z., pandit a.b., 1998, sonophotochemical destruction of aqueous solution of 2, 4, 6 trichlorophenol, ultrason, sonochem. , 5, pp.53-61. 11buchanan i.d., micell j.a., 1997, peroxidase catalyzed removal of aqueous phenol, biotechnol.bioeng. , 54, pp.251261. 12burleigh m.c., markowitz m.a., spector m.s. gaber, 2002, porous poly-silsequioxanes for the adsorption of phenols. eniron.sci.technol.36, pp.25152518. removal of phenolic compounds from aqueous solution by using agricultural waste (al-khriet) 62 ijcpe vol.14 no.3 (september 2013) -available online at: www.iasj.net 13perry r.h., and chilton c.h., 1973, chemical engineers handbook, 5 th edition, mcgraw-hill kogakusha. 14daneshvar n.,aber s., khani a., khataee a.r., 2007. study of imidaciopride removal from aqueous by adsorption onto granular activated carbon using an on-line spectrophotomatric system,j.hazard. mater. 144, pp.4751. 15khosravi r., moussavi g.r., roudbar mohammed sh., 2011, removal of high concentration of phenol from synthetic solutions by fusarium culmorum granules. iran. j. health and environ. , vol.4, no.4. 16soheil aber, alireza khatee, mohsen sheydaei. 2009. optimization of activated carbon fiber preparation from kenaf using k2po4 as chemical activator for adsorption of phenolic compounds. bioresource technology, 100, pp. 6586-6591. 17pietrobelli, j.m.t., modenus m.r., fagundes-kten, f.r., espinoza, 2009, cadmium copper and zinc biosorption study of non living jensa biomass water air soil pollut. 202, 385-392. 18patricia uiretzky and garolina munoz, 2011, enhancement metal removal from aqueous solution by fenton activated macrophyta biomass, desalination, 271, 20-28. 19saraswat s., rai j.p.n., 2010, heavy metal adsorption from aqueous solution using eichhormia crassipes biomass, int j. miner process, 94, 203-206. iraqi journal of chemical and petroleum engineering vol.14 no.2 (june 2013) 2127 issn: 1997-4884 the application of microwave technology in demulsification of water-in-oil emulsion for missan oil fields sawsan a.m. mohammed* and mortatha s. mohammed * chemical engineering department, college of engineering, university of baghdad abstract a series of batch demulsification runs were carried out to evaluate the final emulsified water content of emulsion samples after the exposure to microwave. an experimental study was conducted to evaluate the effects of a set of operating variables on the demulsification performance. several microwave irradiation demulsification runs were carried out at different irradiation powers (700, 800, and 900 watt), using water-in-oil emulsion samples containing different water contents (20-80%, 30-70%, and 50-50%) and salt contents (10000, 20000, and 30000 ppm). it was found that the best separation efficiency was obtained at 900watt, 50% water content and 160 s of irradiation time. experimental results showed that microwave radiation method can enhance the demulsification of water -inoil emulsions in very short time compared to the conventional methods. keywords: demulsification, microwave radiation, water-in-oil emulsion, dielectric introduction water -inoil emulsions are commonly encountered in the petroleum industry, such as in petroleum refineries and transportation stations dealing with crude oil and natural gas through pipelines. emulsions can cause difficulties in crude oil storage and transportation as well as pipeline corrosion. emulsions are undesirable because the volume of dispersed water occupies space in the processing equipment and pipelines and increases operating and capital costs. moreover, the characteristics and physical properties of oil change significantly upon emulsification. the density of emulsion can increase from 800 kg/m 3 for the original oil to 1030 kg/m 3 for the emulsion. the most significant change is observed in viscosity, which typically increases from a few mpa.s or less to about 1000 mpa.s [1] (i. e., emulsion viscosity can be substantially greater than the viscosity of either the oil or the water because emulsions show nonnewtonian behavior. this behavior is a result of droplet crowding or structural viscosity. in order to maintain normal production, emulsions must be broken down for separating water from oil. after separation, the water content in the oil must be below 0.5% [2, 3]. moreover, the oil content must be less than 0.05% in the water separated from the emulsion for environmental reasons and to minimize the loss of oil. therefore, demulsification is very important for the petroleum industry[4]. iraqi journal of chemical and petroleum engineering university of baghdad college of engineering the application of microwave technology in demulsification of water-in-oil emulsion for missan oil fields 22 ijcpe vol.14 no.2 (june 2013) -available online at: www.iasj.net a lot of activities have been developed recently regarding the use of microwave irradiation for demulsification purposes. this is because the microwave irradiation offers a clean, inexpensive, and convenient method of heating, which often results in higher yields and shorter reaction times. however, the reports about the practical application of microwave demulsification are very limited up to now [5]. in microwave irradiation, energy is supplied by an electromagnetic field directly to the material [6]. this results in rapid heating throughout the material thickness with reduced thermal gradients. the microwave energy is volumetric heating, which can reduce processing time and save energy. when microwave is supplied, it attacks the polar molecules which are in this case molecules of water. therefore, molecules get energy and vibration occurs. the vibration will lower the interfacial tension or film around water molecules in the emulsions. this will result in film rapture and increase the degree of water molecules coalescence. the break-down of emulsions is a three step process. in the first step called flocculation, the dispersed droplets of internal phase flocculate into some large group but drops still exist without coalescence. in the next step called coalescence, the drops in group coalesce into a large drop with the result of the decrease of drop numbers. in the sink step, large internal drops sink by gravity to the interface between oil and water and coagulate into water phase resulting in the break-down of emulsion [7]. the main objectives of this study are to examine the performance of microwave application in demulsification of water-in-crude oil emulsions in comparison to the conventional methods and study the influence of the below parameters on demulsification efficiency by microwave: (water content, microwave application power, irradiation time, settling time and salt content). experimental work the demulsification tests applying microwave radiation were conducted using microwave oven (lg), which provide 900w with operation frequency at 2450 mhz. a 900 ml graduated cylindrical glass was used as sample container. three thermocouples type (k) were connected to data logger and then connected to microwave oven as shown in fig. 1. fig. 1, photograph of experimental apparatus materials heavy crude oil was used in this study is supplied by missan oil company. the characteristics of crude oil have given in table 1. table 1, crude oil characteristics characteristic missan crude oil density (20°c ⁄ ) 0.905 api 24 salt content(ppm) 42.92 water content 18% ds 16 viscosity(cp) 22.572 sodium hydroxide was used as an emulsifying agent for emulsion preparation. in the present study. sawsan a.m. mohammed and mortatha s. mohammed -available online at: www.iasj.net ijcpe vol.14 no.2 (june 2013) 23 emulsion preparation in this study, the microwave demulsification method was carried out using different emulsion of water in crude oil emulsions. to assure the stability of emulsion samples prepared in the laboratory, 1ml of 0.95 n naoh solution was added to distilled water used in preparation of samples. emulsions were agitated vigorously using a standard three blade propeller at constant speed of 1800 rpm for 8 minutes to facilitate the contact among the water droplets in the emulsion. the prepared samples were tested for their stability under gravity at room temperature. the amount of water resolved is a measure of the emulsion stability. the system should not be separated into bulk oil and water phases after 3 days of gravity settling. demulsification an experimental study was conducted to evaluate the effects of a set of operating variables on the demulsification performance. several microwave irradiation demulsification runs were carried out at different irradiation powers (700, 800, 900watt), using water –in-oil emulsion samples containing different water contents (20, 30, 50 %) and different salt content (10000, 20000, 30000ppm). after microwave irradiation, emulsion samples were put into graduated cylinders for settling measurements. the volumes of the separated water phase were recorded every 20 minutes for 3 hours. the separation efficiency (s) can be calculated from the following equation: where: s is the separation efficiency vs represents the volume of separated water. vo represents the original volumes of water. results and discussion 1. effect of water content on demulsification efficiency it is necessary to determine the relationship between dielectric properties and the water content in the emulsion, because the dielectric properties are influenced by the medium composition. this is especially important in demulsification processes, where water content variations are expected to occur. besides emulsion water content can also influence the coalescence efficiency during the demulsification process, leading to reduced distance between droplets in the sample. this distance can be severely narrowed with the increase of the volume of the aqueous phase in the emulsion, raising the probability of collision between the droplets [8]. from experimental results, it was observed that when the volume ratio of water is less, the emulsion is more stable. according to figure (2) improved emulsion resolution was obtained for emulsions with greater initial water content. fig. 2, effect of water volume ratio on demulsification efficiency the application of microwave technology in demulsification of water-in-oil emulsion for missan oil fields 24 ijcpe vol.14 no.2 (june 2013) -available online at: www.iasj.net 2. effect of irradiation power on demulsification efficiency separation efficiency and sample temperature continuously increased with microwave irradiation power until no further improvement in efficiency or increase of sample temperature occurred with increasing irradiation power. it can be seen from fig. (3) that an increase in microwave power resulted in higher percentage of water separation, because the wavelength and penetration depth increases along with microwave power [9,10]. fig. 3, effect of different irradiation power for 50-50% w/o 3. effect of microwave irradiation time on demulsification efficiency the separation efficiency continuously increases with irradiation time until 160 sec have passed after that the emulsion starts to boil. the separation efficiency at this irradiation time reaches 85% using 900 w of microwave irradiation for (50-50%) w/o emulsion. from fig. (4), it can be concluded that the microwave exposure time is of great importance for separation of emulsions. less exposure time is not sufficient for large crops of small droplets to coalesce and settle. fig. 4, effect of different irradiation time for 50-50% w/o emulsion 4. effect of salt content on demulsification efficiency the study of the salt content effect on the microwave demulsification can be helpful for breaking emulsions that generated during petroleum production and also during desalting process. the dielectric heating is influenced by the salt content in the aqueous phase. it is also well-known that existence of ionic species in the media enhances the heating efficiency of the mixture [11]. besides, the salt content may also play a role over the interfacial properties of the emulsion and over stability. specific ions present in the brine solution can influence interfacial film behavior. at the interface, these ions may react chemically with hydrophilic groups to form insoluble salts [12]. it can be observed from fig. (5) that water separation efficiency increases with increasing salt content, this could be due to the destroying of the double charge layers by the nacl, as well as the somewhat higher density of the aqueous phase, these results are in agreement with those of xia et. al[13]. to understand this observation, one may consider the characteristic changes in the oil water emulsion behavior as a result of salt (nacl) addition. from the diffuse ion theory, it is known that for the same water sawsan a.m. mohammed and mortatha s. mohammed -available online at: www.iasj.net ijcpe vol.14 no.2 (june 2013) 25 content, as the salt concentration increases, the internal energy of the system increases [14]. fig. 5, effect of different salt content for 5050% w/o emulsion 5. dielectric properties and heating rates of irradiated emulsions the rate of heat generation from microwave radiation depends upon physical and dielectric properties of emulsion. the dielectric constant of water and oil are given by the following equations [15]: where wr , , or , are the dielectric constant of water and oil respectively, t is the temperature increase in °c. the dielectric constant of the emulsion emulsionr , is calculated from wiener equation [16, 17]: where w and o are the volume fractions of water and oil respectively. the rate of temperature increase is calculated from the temperature increase divided by irradiation time. it is observed that the heating rate (dt/dt) is inversely proportional to the increase in temperature; this was an expected result since the dielectric loss of water is small. fig. (6) illustrates the heating rate for of 20 – 80% w/o, 50 – 50% w/o emulsions, and pure water. it could be concluded from the figure that, emulsion with smaller water volume fraction has a higher heating rate due to larger heat generation per unit volume. fig. 6, the relation between water volume ratio and heating rate the ability of sample to absorb and convert thermal heating within the samples is computed by measuring dielectric properties. as shown in fig. (7), it is clear that the dielectric constant depends strongly on the dispersed phase volume fraction. the dielectric constant increases with increasing water volume fraction in emulsion, which can be explained according to weiner equation knowing that the value of dielectric constant of water is much higher than that of oil. this result is in good agreement with that found by [18]. the application of microwave technology in demulsification of water-in-oil emulsion for missan oil fields 26 ijcpe vol.14 no.2 (june 2013) -available online at: www.iasj.net fig. 7, the relation between water volume ratio and dielectric constant conclusions 1. microwave radiation is effective in separating dispersed water from water – in – oil emulsions. the separation is much faster than conventional methods. 2. improved emulsion resolution was obtained for emulsions having higher water volume ratio due to the increase in electrical conductivity and energy dissipation per unit volume and therefore the heating effect. 3. an increase in microwave power resulted in higher percentage of water separation, because the wavelength and penetration depth increases along with microwave power. 4. the microwave exposure time is of great importance for separation of emulsions. the separation efficiency increases with irradiation time due to viscosity reduction which results in a faster film drainage rate and faster drop coalescence. 5. separation efficiency increases with increasing salt content of emulsions; this could be due to the destroying of the double charge layers by nacl that delay the coalescence of water droplets, and higher density of the aqueous phase. 6. emulsions with smaller water volume fraction have a higher heating rate due to larger heat generation per unit volume. 7. the dielectric constant increases with increasing water volume fraction in emulsion. references 1. fingas m. and fieldhouse b. (2003), "studies of formation process of water-in-oil emulsions", marine pollution bulletin 47, 9-12: 369-396. 2. jin qinghan, dai shushan, and huang kama (1999), "microwave chemistry", beijing: science publishing company: 17-22 3. bhardwaj, a. and hartland, s. (1994), "dynamics of emulsification and demulsification of water-in-crude oil emulsions", industrial and engineering chemistry research 33: 1271-1279 4. das p. k., and hartland s. (1990), "effect of demulsifiers on the separation of water-in-oil emulsions", chem. eng. commun. 92:169-181. 5. abdurahman h.n., yunus r.m., and azhary. h.n. (2012), "demulsification of water-in-oil (w/o) emulsion via microwave irradiation: an optimization", scientific research and essays, 7(2): 231-243. 6. thostenson, e.t., and chou, t.w. (1999), "microwave processing: fundamentals and applications", composite, part a, 30:1055-1071. 7. johnk, c.t. (1975), "engineering electromagnetics fields and waves", ed. new york: john wiley. 8. coutinho r.c., heredia m.f., de souza, m.n. and santos a.f. (2008), "method for the microwave treatment of water-in-oil emulsions", us patent 2008/0221226 a1. sawsan a.m. mohammed and mortatha s. mohammed -available online at: www.iasj.net ijcpe vol.14 no.2 (june 2013) 27 9. nuurul huda s. and abdurahman h.n. (2011), "microwave separation of water-in-crude oil emulsions", inter. j. of chemical and environmental eng., 2(1):6975. 10. khan r.m. and emad n. alshafei (2009), "use of advanced nonconventional technology to improve flow properties and upgrading/desulfurizing heavy and high sulfur crude", saudi aramco journal of technology. 11. fortuny m., oliveira c.b.z., melo r.l.f.v., nele m., coutinho r.c.c., and santo a.f. (2007), "effect of salinity, temperature, water content, and ph on the microwave demulsification of crude oil emulsion", energy fuels, 21 :1358–1364 12. mortatha s. mohammed, " the application of microwave technology in demulsification of water-in-oil emulsion for missan oil fields", msc. thesis, chemical engineering department, college of engineering, university of baghdad. 13. xia l.x., lu s.w., and cao g.y. (2004a), "salt-assisted microwave demulsification", chem. eng. comm., 191: 1053-1063. 14. mohamed a.m.o., gamala m, zekri a.y. (2003), "effect of salinity and temperature on water cut determination in oil reservoirs", j. petrol sci. eng. 40: 177-188. 15. fang c.s. and lai p.m.c. (1995), "microwave heating and separation of water-in-oil emulsions", j. microwave power and electromagnetic energy, 30 (1): 46–57. 16. erle u., re pegier m., persch c., and schubert h. (2000), "dielectric properties of emulsion and suspensions: mixture equations and measurement comparisons", inter. microwave power institute. 17. hippel a.r. (1954), "dielectric materials and applications", mit press, cambridge, ma. 18. hanai t., koizumi n., and gotoh r., 1962, "dielectric constants of emulsions", bull. inst. chem. res., kyoto univ., 40: 240. iraqi journal of chemical and petroleum engineering vol.15 no.1 (march 2014) 921 issn: 1997-4884 simulation of batch reactive distillation for biodiesel production from oleic acid esterification nada b. nakkash 1 and sarah r. al-karkhi 2 1 chemical engineering department, college of engineering, university of al-nahrain, baghdad – iraq 2 chemical engineering department, college of engineering, university of baghdad, baghdad – iraq abstract the present work concerns with simulating unsteady state equilibrium model for production of methyl oleate (biodiesel) from reaction of oleic acid with methanol using sulfuric acid as a catalyst in batch reactive distillation. meshr equations of equilibrium model were solved using matlab (r2010a). the validity of simulation model was tested by comparing the simulation results with a data available in literature. uniquac liquid phase activity coefficient model is the most appropriate model to describe the non-ideality of olac-meoh-meol-h2o system. the chemical reactions rates results from eq model indicating the rates are controlled by chemical kinetics. several variables was studied such as molar ratio of methanol to oleic acid 4:1, 6:1 and 8:1, amount of catalyst 0.6, 1.2 and 1.8 g sulfuric acid/g oleic acid, reaction time 36, 57 and 75 minutes, and reaction temperature 100, 120 and 130 o c. taguchi method based on signal to noise ratio was used to determine the best operating conditions for biodiesel production. keywords: equilibrium model, uniquac, biodiesel, oleic acid, rate of reaction introduction biodiesel is an environmental friendly biofuels that consists of alkyl esters derived from the transesterification of triglycerides, esterification of free fatty acids and two-stage process (transesterification and esterification) with low molecular weight alcohols [1,2]. biodiesel fuel has become more attractive because of its environmental benefits due to the fact that vegetable oils and animal fats are renewable biomass sources [3]. biodiesel is considered to be renewable, since the carbon in the oil or fat originated mostly from carbon dioxide in the air. tests show the use of biodiesel in diesel engines results in substantial reductions of unburned hydrocarbons, carbon monoxide and particular matter. the exhaust emissions of total hydrocarbons are on average 67% lower for biodiesel than diesel fuel, the exhaust emissions of carbon monoxide from biodiesel are on average 48% lower than carbon monoxide emissions from diesel and the exhaust emissions of particular matter from biodiesel are 47% lower than overall particulate matter emission iraqi journal of chemical and petroleum engineering university of baghdad college of engineering simulation of batch reactive distillation for biodiesel production from oleic acid esterification 10 ijcpe vol.15 no.1 (march 2014) -available online at: www.iasj.net from diesel. emissions of nitrogen oxides stay the same or are slightly increased. biodiesel emissions show decreased levels of polycyclic aromatic hydrocarbons (pah) and nitrated polycyclic aromatic hydrocarbons (npah), which have been identified as potential cancer causing compounds [4-6]. the higher cost of biodiesel is due to its production mostly from expensive raw materials like edible oils, therefore non-edible oils are suitable for biodiesel production, because edible oils are already in demand and too expensive than diesel fuel. non edible oil is considered to be the wonder biodiesel feed stock because of rapid in growth, higher seed productivity, suitable for tropical regions [7-10]. reactive distillation (rd) is an innovating process which combines both distillation and chemical reaction into a single unit, which saves energy (for heating) and materials. therefore, the rd technology offers many benefits as well as restrictions over the conventional process of reaction followed by distillation or other separation approaches. reducing capital cost, higher conversion, improving selectivity, lower energy consumption, the reduction or elimination of solvents in the process and voidance of azeotropes are a few of the potential advantages offered by rd. this technique is especially useful for equilibrium-limited reactions such as esterification and transesterification reactions [11-21]. in the present work a simulation of batch reactive distillation for biodiesel production from oleic acid and methanol using sulfuric acid as a catalyst is considered. theoretical model consider the batch packed reactive distillation column and the schematic model of j th stage shown in figure 1. fig. 1, schematic diagram of equilibrium stage the mathematical equilibrium model was formulated using the following assumptions: 1constant pressure drop across the column. 2hold-up per stage equal to liquid hold up on stage (i.e. vapor phase molar hold-up is neglected). 3the chemical reactions occur only in the liquid phase. 4vapor-liquid equilibrium is achieved on each stage. 5each stage is considered as a continuous stirred-tank reactor (cstr). 6there is heat transfer in the reboiler and in the condenser, but the interior stages of the column are adiabatic. equations that model the equilibrium stage are given as meshr equations: m: total and component material balances. jjjjj j rlvlv dt dm   11 …(1) jijijjijjijjij ijj rxlyvxlyv dt xdm ,,,1,11,1   …(2) e: equilibrium relation jijiji xky ,,,  …(3) s: summation equations nada b. nakkash and sarah r. al-karkhi -available online at: www.iasj.net ijcpe vol.15 no.1 (march 2014) 11 1 1 ,   c i ji x , 1 , 1   ji c i y …(4) h: enthalpy equation hrrhlhvhlhv dt hdm jjjjjjjjj jj   1111 …(5) r: reaction rate equations [22, 23]. catolacolac wk dt olacd r *][ ][ 1  …(6) where the kinetic constant k1 in equation 6 is given by the arrhenius equation [23]:         rt k 13300 exp27.1 1 …(7) the concentration of oleic acid is replaced by activity, equation 6 becomes: catolacolac wakr * 1  …(8) the activity of i th component was calculated using the following equation: iii ca  …(9) the derivative of the rate reaction is found in yadav, et. al. [24]. vapor-liquid equilibrium relation for non-ideal mixture additional variables such as i  (activity coefficient) and i  (fugacity coefficient) appears to represent the degree of deviation from ideality. i i ii i x k y    …(10) the results of vapor fugacity coefficient by redlich/kowng and peng-robinson cubic equations of state show that the vapor phase has ideal gas behavior and the fugacity coefficient  1. for the present work the activity coefficient i  has been calculated using nrtl, unifac and uniquac method. parameters of nrtl and uniquac are given in tables a-1 and a-2. enthalpy calculation enthalpy of component in vapor phase is estimated through the integration the sensible heat from reference temperature to desired temperature  t t v ii ref dtcph …(11) evaluation of integral in equation 11 requires knowledge of the temperature dependence of heat capacity. ]] )cosh( )( [] )sinh( )( [[ 22 t e t e t c t c bacp v i  …(12) the constants a, b, c, and d for all components in vapor are given in table a-3. the total enthalpy of vapor phase is:   t t v i n i i v ref dtcpyh 1 …(13) the enthalpy of component in liquid phase is estimated through the integral of heat capacity in vapor phase from reference temperature to desired temperature then substrate from heat of vaporization. simulation of batch reactive distillation for biodiesel production from oleic acid esterification 12 ijcpe vol.15 no.1 (march 2014) -available online at: www.iasj.net i t t v ii ref dtcph   …(14) the heats of vaporization at normal boiling point for each component is given in table a-4. the total enthalpy of liquid phase is given by equation 15: mixi n i t t v ii l hdtcpxh ref    )(1  …(15) the heat of reaction at 298.15 k is given by equation 16: )( 1 liqhvhr c i o fii    …(16) the sign of stoichiometric ratio v is positive for products and negative for reactants.  )()( 0 gashliqh f o f …(17) the heats of formation of vapor at 298.15k for each component are given in table a-4. the heat of reaction at any temperature is calculated by equation 18:   t t v i ref dtcphrhr …(18) vapor pressure calculation the vapor pressure of each component for the present system was calculated using antoine equation. ct b alnp o   …(19) where vapor pressure o p in pa and t in kelvin. parameters of antoine equation for each component are given in are given in table a-5. bubble point calculation temperatures of stages have been calculated using iterative procedure of bubble point until the summation in equation 20 equals to one. 1)( 1   m i ijij xk …(20) where k is the distribution coefficient and it can be calculated using: p p k o i ii  …(21) holdup in the present work the equilibrium model was considered for tray columns, to change packed columns to the concept of the equilibrium stage, the idea of the height equivalent to a theoretical stage (hets or hetp) was considered. hetp value represents a certain bed length of a packing equivalent to one theoretical stage, hetp for the random packing [25]. indfthetp p ,5.1,  …(22) molar holdups in condenser system and on the column stages based on constant volume holdups, j g :     n i wi j j i i mx g m 1  , where j=1 to n-1 …(23) the holdup in reboiler based on the initial charge to the reboiler (  m ) and it is given by [25]:      n j t tjnn dtdmmm 1 0 …(24) nada b. nakkash and sarah r. al-karkhi -available online at: www.iasj.net ijcpe vol.15 no.1 (march 2014) 13 stages numbered down from top, consider n=1 for condenser. solution of the equilibrium model theoretical model for an equilibrium stage is considered for batch unsteadystate distillation column consisting of a number of stages arranged in a counter current cascade, where the stages are numbered from top to the bottom. in this column, the reboiler and the condenser are assumed as an equilibrium stages. the determination of phase composition and its temperature can be done by solution of material balance equations. the solution of material balance equations are derived for the overhead condensing system, the column stages and reboiler as follow: 1. the overhead section olaci i i i rx m kv x m dt dm dl dt dx    2, 1 2,2 1, 1 1 1 1, ][ …(25) drl * 1  …(26) 2. the stage section olacji j jij ji j j jjij ji j jji rx m kv x m dt dm vkl x m l dt dx        1, 1,1 , , 1, 1, ][][][ …(27) 3. the reboiler section olacni n n nni ni n nni rx m dt dm vk x m l dt dx      , , 1, 1, ][][ …(28) the matrix balance equations are reduced to a tri-diagonal matrix form for batch reactive distillation:                                                               dt dx dt dx dt dx dt dx dt dx x x x x x ba cba cba cba cb a ni ji ji i i ni ji ji i i nn jjj jjj , 1, , 2, 1, , 1, , 2, 1, 111 222 11 000 00 00 00 000 …(29) the general solution of such system is as follow. 12122211 1221 vecvecvecx tλtλtλ  …(30) where 1 c to 12 c is constants of equation. 1  to 12  is eigenvalues of a matrix a . 1 v to 12 v is eigenvalues of a matrix a . this set of equations may be formally written as the following matrix equation: dt dx xa ji, .  …(31) where              1 0 1 1 1 1 m dt dm dl b a , j=1 …(32) olac i r m kv c        1 1,1 1 , j …(33)           j j j m l a 1 , 12  nj …(34) simulation of batch reactive distillation for biodiesel production from oleic acid esterification 14 ijcpe vol.15 no.1 (march 2014) -available online at: www.iasj.net           j jjij j m vkl b )( , , 12  nj …(35) olac j jji j r m vk c           1, , 12  nj …(36)         n n n m l a 1 , j=n …(37) olac n nin n r m kv b        , , j=n …(38) 0 n c after calculating dt dx ji, from algorithm matrix the mole fraction xi,j is calculated from eigen-value. the values of mole fraction xi,j are corrected to provide better values of the assumed iteration variables for the next trial, therefore, for each iteration the computed set xi,j values for each stage will normalized using the following relation:      c i ji ji normalizedji x x x 1 , , , …(39) the modified h equations are obtained first by calculating the vapor phase enthalpy, and then the liquid phase enthalpy is calculated which depends on vapor phase enthalpy. secondly calculate the vapor flow rate vj then the heat supplied to condenser.    c i iji r j x q v 1 ,  , at initial mole fraction …(40)               dt dh mhhlhhv hh v l j j l j l jj l j v jjl j v j j )()( )( 1 11 1 1 …(41) dt dh mhhvq l lv c 1 1122 )(  …(42) a computer program to solve the meshr equations has been developed using matlab (r2010a) to determine the composition of components, segments temperatures, condenser and reboiler duties, liquid and vapor flow rates along stages, and reaction rate profile. the program begins with specify all parameters that consist of number of stages, reflux ratio, total pressure, feed compositions, distillate rate, batch time, step time, and mass of catalyst, as well as all physical properties of components. time, and temperature loops were started, respectively over all stages. the temperature of each stage has been calculated by trial and error until the equilibrium relation applicable. the new segments temperatures have been used in calculation of reaction rate, enthalpies of vapor, liquid and mixing. then the liquid and vapor flow rates were calculated by total material and energy balances. a tridiagonal matrix was used to find the component compositions by solving the meshr equations, solving the matrices by eigen value, and normalizing the new compositions for each component. new sets of composition are obtained with the previous procedure for each step time of the batch time. when the compositions at different times are evaluated the program ended and the results plotted. selection of activity coefficient model to simulate the non-ideal batch reactive distillation column, a good nada b. nakkash and sarah r. al-karkhi -available online at: www.iasj.net ijcpe vol.15 no.1 (march 2014) 15 thermodynamic model is required to represent the vle for the system used. the liquid phase activity coefficient model should be selected carefully to represent the non-idealities of the liquid phase. nrtl, uniquac and unifac models have been used to calculate the activity coefficient to select the appropriate liquid phase activity coefficient model for olac-meohmeol-water system; different activity coefficient models were compared with the experimental results taken from oliveira, m.b., et. al. [26]. the experimental data was at atmospheric pressure. the experimental boiling point temperature of the system was compared with the predicted boiling point temperature from each of the activity coefficient models. figure 2 shows that the uniquac points nearly fall on the diagonal, indicating that the uniquac liquid phase activity coefficient model is the most appropriate model to describe the non ideality of olac-meoh-meolh2o system. fig. 2, comparison between experimental and predicted boiling points checking the validity of the unsteady state equilibrium model the proposed unsteady state equilibrium model was consider for producing methyl oleate as a biodiesel by esterification process in batch reactive distillation column, the results of theoretical part with the experimental from the literature [22] were compared with the results of the developed model. to the best of our knowledge, there is no information about the simulation of batch reactive distillation column for the production of biodiesel (methyl oleate) is available in literature, so the experimental results obtained from the literature [22] have been checked with the results obtained from the unsteady state equilibrium model to give the validity of the model. the comparison results give the ability of the model to predict the results of experiment performed with the same variables of experimental from the literature [22]. figure 3 shows the points are nearly fall on the diagonal indicating that the developed model is in good agreement with the experimental work. fig. 3, plot for the eq model validation also the developed model was checked with experimental work from literature kusmiyati et. al., [8] which provides the conversion of oleic acid in batch reactive distillation at molar ratio of methanol to oleic acid is 8:1, amount of catalyst is 1 g sulfuric acid/g oleic acid and time 90 min. even though the experimental temperature and time of reaction used by kusmiyati et. al., [8] is not within the parameter ranges of the model, but the model still gives a nearly quantitative accurate prediction of the conversions. 60 80 100 120 140 160 60 80 100 120 140 160 experimental boiling point temperature ( o c) p re d ic te d b o il in g p o in t t e m p e ra tu re ( o c ) uniquac unifac nrtl 0 0.2 0.4 0.6 0.8 1 0 0.2 0.4 0.6 0.8 1 x equilibrium model x e x p e ri m e n t olac meol simulation of batch reactive distillation for biodiesel production from oleic acid esterification 16 ijcpe vol.15 no.1 (march 2014) -available online at: www.iasj.net equilibrium model results the best conditions for the largest conversions of oleic acid were based on the s/n ratio [22] statistically analysis by taguchi method [27-29], the best variables were feed molar ratio meoh/olac 8:1, catalyst amount 1.2 g sulfuric acid/g oleic acid, time 57 min and reaction temperature130°c. the biodiesel production system details were found in [22]. figure 4 shows experimental and equilibrium model results for composition profile of oleic acid and methyl oleate in the still for the best conditions. fig. 4, experimental and theoretical equilibrium model results for composition profile in the still, molar ratio 8:1, catalyst amount 1.2, 57 min, 130 ˚c figure 4 shows that, at a first step time the composition of oleic acid increases due to the removal of methanol is removed by distillation, hence the oleic acid mole fraction increases (excess methanol), and the reaction temperature is higher than the boiling point of methanol. figure 5 shows the % conversion of oleic acid with time for experimental and theoretical equilibrium model. fig. 5, % conversion profile for equilibrium model for best conditions initial mole fractions and the operating conditions for different molar ratios, catalyst amounts, reaction time and reaction temperature for the equilibrium model are given in tables 1 and 2. table 1, initial mole fractions of equilibrium model feed molar ratio meoh/olac mol% olac mol% meoh mol% meol mol% water 4:1 0.1875 0.75 0.03125 0.03125 6:1 0.1333 0.7998 0.03345 0.03345 8:1 0.1 0.8 0.05 0.05 table 2, operating conditions for proposed eq program pressure (pa) 101325 hold up per each stage (ml) 11.2 d: feed molar ratio d (gmol) 0.66 reflux ratio (mol/mol) 0.001 total stages 4 boiler heat duty (w) 200 rate of reaction the chemical reaction of esterification is first order with respect to oleic acid and of zeroth order with respect to methanol due to the use of excess methanol. the reaction occurs in liquid phase, and because of the high boiling point of oleic acid the reaction takes place in the still, so the effect of reaction rate is studied in still. figure 6 shows that the average rate of esterification increases with increasing of catalyst amount, which gives an increase in conversion. from equation 8 the rate of esterification is proportional with amount of catalyst, which causes an increase in conversion, this indicate that the reaction is kinetically controlled [22]. 0 10 20 30 40 50 60 0 0.2 0.4 0.6 0.8 1 time ( min) m o le f r a c t io n s t il l olac eq meol eq olac experimental meol experimental 0 10 20 30 40 50 60 0 20 40 60 80 100 time ( min) % c o n v e r s io n equilibrium model experimental nada b. nakkash and sarah r. al-karkhi -available online at: www.iasj.net ijcpe vol.15 no.1 (march 2014) 17 fig. 6, effect of catalyst amount on average rate of esterification reaction figure 7 show that the increases of molar ratio of methanol to oleic acid the average rate of esterification is decreased. this is because of the increasing of conversion of oleic acid to biodiesel, so the concentration of oleic acid decreases, and the rate of esterification is proportional with the concentration of oleic acid, equation 8. fig. 7, effect of molar ratio on average rate of esterification reaction in general in all nine experiments the initial rate of esterification increases with increasing of time and then decreased, figure 8. this is because the composition of oleic acid increases by removing of methanol by distillation. figure 9 shows that the average rate of esterification increases with the increasing of time of reaction. this is because of the long contact time between reactants. figure 10 shows that the average rate of esterification increases with increasing of temperature of reaction. this is because of the temperature of reaction is higher than boiling point of methanol, so the amount of methanol in reaction mixture decreases and the oleic acid remains increases (rate of reaction equation). fig. 8, effect of time on rate of esterification reaction, best experiment fig. 9, effect of time on average rate of esterification reaction fig. 10, effect of reaction temperature on average rate of esterification reaction the effect of variables studied in the present on the rate of esterfication show that the reaction is kinetically controlled. conclusion in the present work, the esterfication of oleic acid to produce biodiesel in batch reactive distillation column was simulated using matlab (r2010a). 0 0.5 1 1.5 2 1 1.5 2 2.5 3 3.5 x 10 -3 catalyst amount (g sulfuric acid / g oleic acid) a v e ra g e r a te o f e s te rf ic a ti o n ( k g m o l/ h r) 4 5 6 7 8 0.5 1 1.5 2 2.5 3 x 10 -3 molar ratio (meoh/olac) a v e ra g e r a te o f e s te rf ic a ti o n ( k g m o l/ h r) 0 10 20 30 40 50 60 0 0.002 0.004 0.006 0.008 0.01 time (min) r a te o f e s te rf ic a ti o n ( k g m o l/ h r) 30 40 50 60 70 80 1.5 2 2.5 x 10 -3 time (min) a v e ra g e r a te o f e s te rf ic a ti o n ( k g m o l/ h r) 100 105 110 115 120 125 130 1.5 2 2.5 x 10 -3 temperature ( o c) a v e ra g e r a te o f e s te rf ic a ti o n ( k g m o l/ h r) simulation of batch reactive distillation for biodiesel production from oleic acid esterification 18 ijcpe vol.15 no.1 (march 2014) -available online at: www.iasj.net the model results show a good agreement with results available in literatures. uniquac liquid phase activity coefficient model is the most appropriate model to describe the nonideality of olac-meoh-meol-h2o system. the best operating conditions to produce biodiesel were feed molar ratio meoh/olac 8:1, catalyst amount 1.2 g sulfuric acid/g oleic acid, time 57 min and reaction temperature130 °c. the average rate of esterification increases with increasing of catalyst amount, time of reaction and temperature which gives an increase in conversion indicating that the reaction is kinetically controlled. nomenclature symbols notation ij a parameter for the interaction between components of the nrtl. a constant ij b parameter of the nrtl. b constant c constant l cp specific heat of liquid v cp specific heat of vapor p d outside diameter of packing d constant e constant ij g parameter of the nrtl equation. ih enthalpy of component i l h total enthalpy of liquid phase v h total enthalpy of vapor phase l h liquid hold up in packing. mix h heat of mixing o r h standard heats of reaction. r h heats of reaction ji k , equilibrium constant for component i in stage j hetp height equivalent to theoretical plate hets height equivalent to theoretical stage l liquid flow rate cat m mass of catalyst wi m molecular weight i m molar hold up t n number of stages c n number of components p pressure op vapor presure q heat duty i q area parameter of component i in uniqac and unifac models r gas constant = 8.314 ffa r reaction rate olac r reaction rate of olaic acid r 2 coefficient of multiple determination r linear correlation coefficient for sample i r volume parameter of component i in uniquac and unifac models t temperature ref t reference temperature ij u parameter of interaction between component i and j in uniquac model v vapor flow rate cat w weight of sulfuric acid i x liquid mole fraction i y vapor mol fraction greek letters  kinematic viscosity at 40°c i  fugacity coefficient of component i in mixture i  activity coefficient of component i in mixture ij  non randomness parameter (nrtl parameter) – empirical constant  liquid molar density nada b. nakkash and sarah r. al-karkhi -available online at: www.iasj.net ijcpe vol.15 no.1 (march 2014) 19 abbreviations fa fatty aacid ffa free fatty acid fame fatty acid methyl ester meoh methanol meol methyl oleate nrtl nonrandom, twoliquid theory olac oleic acid rd reactive distillation unifac uniquac functional group activity cofficients uniquac universal quasichemical theory references 1lotero, e.; liu, y.; lopez, d.e.; suwannakarn, k.; bruce, d.a.; goodwin, j.g. synthesis of biodiesel via acid catalysis. ind. eng. chem. res., 44(14), 53535363(2005) 2isyama, y.; saka, s. biodiesel production by supercritical process with crude bio-methanol prepared by wood gasification. bioresourse technology, 99, 4775-4779 (2008) 3cardoso, a.l.; neves, s.c.g;. da silv., m.j. esterification of oleic acid for biodiesel production catalyzed by sncl2: a kinetic investigation. energies, 1, 79-92 (2008) 4kiss, a.a.; dimian, a.c.; rothenberg, g. biodiesel by catalytic reactive distillation powered by metal oxides, energy and fuels, 22, 598-604 (2008) 5halek, f.; kavousi, a.; banifatemi, m. biodiesel as an alternative fuel for diesel engines. world academy of science, engineering and technology, 57 (2009) 6gerpen, j. biodiesel processing and production. fuel processing technology 86, 1097– 1107 (2005) 7aranda, d.a.g.; santo, r.p.t; tapanes, n.c.o.; ramos, a.l.d.; antunes, o.a.c. acid-catalyzed homogenous esterfication reaction for biodiesel production from palm fatty acids. springer, 122, 20–25 (2008) 8kusmiyati, sugiharto, a. “production of biodiesel from oleic acid and methanol by reactive distillation”, bulletin of chemical reaction engineering and catalysis (bcrec), (2010) 9marchetti, j.m.; miguel, v.u.; errazu, a.f. hetrogenous esterfication of oil with high amount of free fatty acids.fuel, 86, 906-910 (2010) 10marchetti, j.m.; pedernera, m.n.; schbib, n.s. production of biodiesel from acid oil using sulfuric acid as catalyst:kinetics study. international journal of lowcarbon technologies, october 15, 1-6 (2010) 11budiman, a.; kusumaningtyas, r.d.; sutijan; rochmadi; purwono, s. second generation of biodiesel production from indonesian jatropha oil by continous reactive distillation, aiche, vol 9, no. 2, 35-48 (2009) 12singh, a. p.; thompson, j. c.; he, b. b. a continuous-flow reactive distillation for biodiesel preparation from seed oil, asae/csae meeting presentation, 1-4 august (2004) 13he, b. a novel continuousflow reactor using reactive distillation technique for economical biodiesel production, national institute for advanced transportation technology university of idaho, (2006) 14kiss, a.a.; dimian, a.c.; rothenberg, g. solid acid catalysts for biodiesel production towards sustainable energy, adv. synth. catal., 348, 75 – 81 (2006) 15fortin, t.; thériault, p., design of a continuous flow biodiesel simulation of batch reactive distillation for biodiesel production from oleic acid esterification 20 ijcpe vol.15 no.1 (march 2014) -available online at: www.iasj.net production research unit in india. collaboration project between mcgill univesity bioresource engineering department and tamil nadu agriculture university, (2008) 16kiss, a.a., separative reactors for integrated production of bioethanol and biodiesel. computers and chemical engineering, (2009) 17n. de lima da siliva; santander, c.m.g.; et. al., biodiesel production from integration between reaction and separation system: reactive distillation process. app biochem biotechnol, springer science, 161, 245-254 (2010) 18n. de lima da siliva; santander, c.m.g.; et. al., biodiesel production from reactive distillation process: a comparative between experimental and the simulation. distillation absorption, 307-312 (2010) 19mueanmas, c.; prasertsit, k.; tongurai, c. feasibility study of reactive distillation column for transesterification of palm oils. international journal of chemical engineering and applications, vol. 1(2010) 20phuenduang, s.; siricharnsakunchai, p.; simasatitkul, l.; paengjuntuek, w.; arpornwichanop, a. optimization of biodiesel production from jatropha oil using reactive distillation. tiche international conference, november 10 – 11, at hatyai, songkhla thailand (2011) 21machado, g.d.; aranda, d.a.g.; castier, m.; cabral, v.f.; filho, l.c. computer simulation of fatty acid esterification in reactive distillation columns”, ind. eng. chem. res., 50, 10176– 10184(2011) 22al-karkhi, s.r. “simulation and experimental investigation for production biodiesel using batch reactive distillation”, m. sc. thesis, al-nahrain university, baghdad, iraq (2012). 23sendzikiene, e.; makareviciene, v.; janulis, p.; kitrys, s. “kinetics of free fatty acids esterification with methanol in the production of biodiesel fuel”, eur. j. lipid sci. technol, 106, 831–836(2004). 24yadav, p.k.s.; singh, o.; singh, r. p. palm fatty acid biodiesel: process optimization and study of reaction kinetics. journal of oil science, 59, 11,575-580 (2010) 25seader, j.d.; henley, e.j. separation process principles”, john wiley and sons, inc., new york (1998) 26oliveira, m.b.; miguel, s.i.; queimada, a.j.; and coutinho, j.a.p. phase equilibria of ester + alcohol systems and their description with the cubic-plusassociation equation of state. ind. eng. chem. res., 49, 3452-3458 (2010) 27mahamuni, n.n. and adewuyi, y.g.. “application of taguchi method to investigate the effects of process parameters on the transesterification of soybean oil using high frequency ultrasound”, energy fuels, 24, 2120-2126, (2010) 28roy, r.k. design of experiments using the taguchi approach: 16 steps to product and process improvement. new york: wiley, (2001), as sign in kim, s. et. al. (2010) 29taguchi, g. introduction to quality engineering; unipub/kraus international: white plains, (1986), as sign in mahamuni, n.n., et. al. (2010) nada b. nakkash and sarah r. al-karkhi -available online at: www.iasj.net ijcpe vol.15 no.1 (march 2014) 21 table a-1, nrtl parameters for the binary pairs of components in the reactive mixtures ji  ij b ji b ij  olacmeoh 199.884 479.688 1.1431 meohh2o -24.4933 307.166 0.3001 olacmeol 37.63835 36.76161 0.2907206 olach2o -44.8289 2497.61 0.2250879 meoh-meol 1388.564 -240.4565 0.399494 meolh2o 106.4762 2499.963 0.200312 table a-2, uniquac parameters for the oleic acid – methanol – methyl oleate – water mixture, cal/gmol ji  jjij uu  iiji uu  olacmeoh 952.028 -149.181 meoh h2o 95.259 -10.377 olacmeol 154.7875 -133.418 olac h2o 1123.794 403.7021 meohmeol -54.20368 1205.077 meol h2o 1573.999 481.5153 table a-3, heat capacity constants in vapor phase in j/kgmol.k component a b c d e range temperature k olac 3.2*10 5 9.362*10 5 -1.7431*10 3 6.754*10 5 7.825*10 2 298.15-1500 meoh 3.9252*10 4 8.79*10 4 1.9165*10 3 5.3654*10 4 8.967*10 2 200-1500 meol 3.2997*10 5 9.716*10 5 -1.6456*10 3 6.7448*10 5 7.48*10 2 300-1500 water 3.3359*10 4 2.6798*10 4 2.6093*10 3 8.888*10 3 1.1676*10 3 100-1500 table a-4, physical properties component normal boiling point, k ∆h o f (298.15k) [kj /g.mol] of vapor λ [kj / kg.mol at nbp olac 633 -646.02 68131 meoh 337.85 -201.3 35278 meol 617 -649.9 63625 water 373.15 -242 40683 table a-5, vapor pressure constants antonio coefficient component c b a -127.26 5884.49 23.1373 olac -34.29 3626.55 23.4803 meoh -96.15 5948.17743 22.8313 meol -46.13 3816.44 23.1964 water iraqi journal of chemical and petroleum engineering vol.14 no.3 (september 2013) 19 issn: 1997-4884 synthesis, characterization and evaluation of overbased magnesium fatty acids detergent for medium lubricating oil abdul halim a-k mohammed * , mohammed r. ahmad ** and zainab a. k. al-messri ** *chemical engineering department, college of engineering, university of baghdad ** department of chemistry, college of science, university of baghdad abstract a series of overbased magnesium fatty acids such as caprylate, caprate, laurate, myristate, palmitate, stearate and oleate) were synthesized by the reaction of the fatty acids with active – 60 magnesium oxide and carbon dioxide (co2) gas at 60 o c in the presence of ammonia solution as catalyst, toluene / ethanol solvent mixture (9:1vol/vol) was added. the prepared detergent additives were characterized by ftir, 1 hnmr and evaluated by blending each additive in various concentrations with medium lubricant oil fraction (60 stock) supplied by iraqi midland refineries company. the total base number (tbn, mg of koh/g) was determined, and the results of tbn were treated by using two-way analysis of variance (anova) test. it was found that the number of carbons in the fatty acid (c8-c18) used for overbased detergent preparation had slight effect on the tbn of the oil, while detergent concentrations (1-5% wt/wt) had a significant effect on the tbn of the blended oil. the oxidation stability of the oil blends with 2% of overbased magnesium palmitate and overbased magnesium stearate detergents was evaluated, and the results showed that these blends gave higher oxidation stability compared with the blends with standard antioxidant supplied by midland refineries company. keywords: overbased detergent, fatty acid, lubricant oil, tbn. introduction lubricants are an important family among products of the refining industry. a lubricant performs a number of critical functions, these include lubrication, cooling, cleaning and suspending, and protecting metal surfaces against corrosive damage [1]. lubricant comprises a base fluid and an additive package. additives can be defined as substances which improve the performance of lubricants, either by imparting new properties to a base oil (cleaning and suspending ability, antiwear performance, and corrosion control), or by enhancing properties already present (viscosity, viscosity index, pour point, and oxidation resistance). the use of additives began in the 1930’s and enormous growth has been seen since in both their production rates and the scope of their applications [2]. modern equipment must be lubricated in order to prolong its lifetime. one of the most critical properties of the automotive lubricants, especially engine oils, is their ability to iraqi journal of chemical and petroleum engineering university of baghdad college of engineering synthesis, characterization and evaluation of overbased magnesium fatty acids detergent for medium lubricating oil 2 ijcpe vol.14 no.3 (september 2013) -available online at: www.iasj.net suspend undesirable products from thermal and oxidative degradation of the lubricant. it has been found necessary to incorporate detergent additives in oils for such service in order to avoid the engine failure [3]. modern diesel engine lubricants derive most of their alkalinity from overbased detergents such as sulfonates/phenates/salicylates of calcium, or magnesium [4]. over-based detergents are salts of alkaline earth metals such as calcium and magnesium that contain more alkaline metal than that required for their manufacture. thus, they have both a good detergent property and an excellent ability to neutralize strong acids. detergent additives prevent or disperse an accumulation of sludge in the crankcase at high or low temperatures [5]. the term “overbased” refers to the fact that the quantity of base incorporated in the particle cores is greater than that needed to neutralize the acid surfactant. the neutralizing strength of an overbased detergent is measured by its total base number (tbn). tbn is defined as the quantity of acid, expressed in terms of the equivalent number of milligrams of potassium hydroxide that is required to neutralize all basic constituents present in 1 g of overbased detergent [6]. recently, the use of environmentally friendly lubricant base oils [7-9] increased, as did the necessity of studying their environmentally friendly additives. new environmentally friendly overbased detergents were synthesized [10-14]. this work deals with preparation of lubrication oil overbased detergents from different fatty acid and testing their efficiency. experimental work materials 1. chemicals table (1) shows the properties and manufacturers of the used chemicals. table 1, chemicals and their properties and manufactures no. chemicals molecular weight mp., ο c purity,% supplier 1. caprylic acid 144.22 15-17 98 bdh chemicals ltd. 2. capric acid 172.27 29-31 99 bdh chemicals ltd. 3. lauric acid 200.32 43-44 98 h and w ltd. 4. myristic acid 228.38 53-54 97 h and w ltd. 5. palmitic acid 256.43 61-63 99 bdh chemicals ltd. 6. stearic acid 284.48 67-69 95 merck 7. oleic acid 282.47 13-14 97 h and w ltd. 8. magnesium oxide 40.31 _ 99 bdh chemicals ltd. 9. toluene 92.14 (bp., ο c) 110-111 99 fluka ag 10. ethanol 46.07 (bp., ο c) 79-81 95 bdh chemicals ltd. 11. ammonium hydroxide 17.03+aq _ 20-25 in water fluka ag 12. co2 gas 44 _ high purity national gas manufacturing company 2. base oil base lubrication oil 40 stock and 60 stock supplied by midland refineries company, 40 stock was used as a diluents in preparation of overbased magnesium fatty acid detergents, while 60 stock was used for preparation of oil blends with the prepared detergents. abdul halim a-k mohammed, mohammed r. ahmad and zainab a. k. al-messri -available online at: www.iasj.net ijcpe vol.14 no.3 (september 2013) 3 the properties of these oils were listed in table (2). table 2, properties of base lubricating oil 40 stock and 60 stock no. specification 40 stock 60 stock standard test method 1. kinematic viscosity at 40 °c, cst (mm²/s) 13.16 62.71 astmd 445 2. kinematic viscosity at 100 °c, cst (mm²/s) 3.12 8.13 astmd 445 3. viscosity index 94 95 astm d2270 4. specific gravity at 60/60 οf 0.856 0.88 astm d-4052 5. pour point ,°c -12 -9 astm d-97 6. flash point (c.o.c),°c 198 240 astm d-92 7. color 1.0 (pale yellow) 2.5 (yellowish) astm d-1500 instrumentation fourier transform infrared (ftir) spectra were recorded on shimadzu ftir-8400s spectrophotometer, department of chemistry, college of science , baghdad university as kbr disc to detect the functional groups in the region 4000-400 cm -1 . 1 h-nmr spectra were recorded on a burker model ultra-shield dpx400mhz, cardiff university, u.k., using cdcl3 as solvent and tetramethylsilane si(ch3)4 as internal reference . all data are given as chemical shifts δ (ppm) downfield from tetramethylsilane. synthesis of overbased magnesium fatty acid detergents the synthetic procedure of overbased magnesium fatty acids detergent is similar to that described by yonglei wang, and wumanjiang eli [13], but the xylene and methanol solvent change to toluene and ethanol, respectively. different magnesium fatty acid detergents were prepared, using a three neck 500 ml round bottom flask fitted with a gas dispersion tube, condenser, and mechanical stirrer as a reactor shown in fig. (1). 0.05 mol of the desired fatty acid and 20 g of diluents oil were added to the flask and dissolved in 100 ml of mixture of toluene and ethanol (9:1), then 20.15 g of active-60 magnesium oxide (0.5 mol) was added to the diluted mixture. the resulted mixture was stirred for 1 h and then heated up to 65 ο c. 10ml of ammonia solution was added to the mixture and 60 ml/min of gaseous co2 for 3.5 h was then introduced into the reactor through gas dispersion tube via the gas flow meter. the desired overbased magnesium fatty acid detergent was obtained by filtration through fluted filter paper for residue removal, and filtrate evaporation to remove the solvents. fig. 1, schematic diagram of the reactor formulation of oil blends blends of different prepared overbased magnesium fatty acid detergents (c8 c18:0 and c18:1) were prepared by dissolving each detergent in a mixture of toluene and xylene synthesis, characterization and evaluation of overbased magnesium fatty acids detergent for medium lubricating oil 4 ijcpe vol.14 no.3 (september 2013) -available online at: www.iasj.net (1:1) at 60 ο c for 1 hour. the prepared 60 stock oil blends contain different dosages (1%, 2%, 3.5% and 5%) of each of synthesized detergent. test methods total base number (tbn, mg of koh/g) was determined according to american society of testing and materials astm d-4739, this standard method is based on the potentiometric titration of the basic constituents in an oil with standardized hydrochloric acid to a fixed endpoint. oxidation stability was determined according to ip 280, which measures the tendency for a lubricant to generate sludge and/or solid oxidation byproducts. total oxidation products (top) include products formed from decomposition of hydro peroxides regardless of their chemical form. thus, top is a good indicator of total conversion and overall extent of oxidation. results and discussion the chemical structure and total base number for the prepared magnesium overbased detergents are listed in table (3). table 3, nomenclature, structure, color and tbn of synthesized overbased detergents no. abbreviation common name systematic name chemical structure color tbnmg koh/g 1. c8:0 magnesium caprylate magnesium octoate (ch3(ch2)6coo)2mg. nmgco3 pale yellow 76 2. c10:0 magnesium caprate magnesium decanoate (ch3(ch2)8coo)2mg. nmgco3 white 103 3. c12:0 magnesium laurate magnesium dodecanoate (ch3(ch2)10coo)2mg. nmgco3 white 123 4. c14:0 magnesium myristate magnesium tetradecanoate (ch3(ch2)12coo)2mg. nmgco3 pale yellow 258 5. c16:0 magnesium palmitate magnesium hexadecanoate (ch3(ch2)14coo)2mg. nmgco3 pale yellow 346 6. c18:0 magnesium stearate magnesium octadecanoate (ch3(ch2)16coo)2mg. nmgco3 white 420 7. c18:1 magnesium oleate 9octadecenoic acid magnesium salt (ch3(ch2)7ch=ch (ch2)7coo)2mg. nmgco3 pale yellow 398 the structureof the synthesized compounds were confirmed by ftir, and 1 h nmr spectroscopy as shown in table (4). ftir spectra of the prepared compounds showed asymmetric 29182927 cm -1 for (ch2) group, while symmetric stretching band for (ch2) group appeared between 28502854 cm -1 . a band in the region 719-723 cm -1 refers to the methylene rocking vibration for straight chain [15]. the carboxylate ion gave a strong asymmetrical stretching band between 1578-1560 cm -1 [16]. 1 h nmr spectra of two of the prepared compounds (c16:0 and c18:0) showed the signals at  0.8 for ch3 and  1.2 1.3 for (ch2)n because the long chain r group have resonances that occur over a very narrow range. the two protons near to carboxylate (ch2coo) appeared at  1.9-2.0 [17]. abdul halim a-k mohammed, mohammed r. ahmad and zainab a. k. al-messri -available online at: www.iasj.net ijcpe vol.14 no.3 (september 2013) 5 table 4, ftir and 1 hnmr spectral data of synthesized overbased detergents no. abbreviation major ftir absorptions cm-1 1h-nmr ( ppm) ch3 ch2 (c=o) δch2 rocking ch3 (ch2)n ch2– co 1. c8:0 as.2956 as.2927 s.2854 1577 723 2. c10:0 as.2958 as.2923 s.2854 1560 721 3. c12:0 as.2955 as.2924 s.2854 1578 721 4. c14:0 as.2954 as.2920 s. 2850 1560 721 5. c16:0 as.2954 as.2918 s.2850 1568 719 0.8 1.3 2.0 6. c18:0 as.2956 as.2922 s.2850 1571.8 721 0.8 1.2 1.9 7. c18:1 as.2955 as.2924 s.2854 1570 723 (=ch) 3006.8 the surfactants that are used to prepare the overbased detergent contain a polar hydrophilic head and a long, non-polar organic chain. the polar head-group typically links to calcium, magnesium or barium cations. the colloidal particle consists of a core of basic metal carbonate or a mixture of metal carbonate and metal hydroxide depending on the cation species. the core of the colloidal particle is stabilized by a monolayer of surfactant and the core radius is in a size range of 1.5 — 10 nm. [18] the schematic diagram of prepared overbased magnesium fatty acid detergent particle may be present in fig. (2). total base number were determined for the 60 stock oil blends with different overbased magnesium fatty acid detergent in different dosages according to astm d-4739, and the results are shown in table (5). the results of tbn were treated by using two-way analysis of variance (anova) tests to measure the effects of two factors ,number of carbons in the synthesized overbased detergents (c8-c18) and their concentrations (15% wt/wt) in the blended oil simultaneously. fig. 2, schematic diagram of prepared overbased detergent particle table (6) shows the effect between subjects and summarized anova. this table show the sum of squares, degree of freedom, mean squares, fvalue and the significant test results .the significant level of using different carbon numbers in the detergent have a value of 0.620 which means that there is no significant difference because the significant level is greater than 0.05 (95% confidence), while the significant level obtained for synthesis, characterization and evaluation of overbased magnesium fatty acids detergent for medium lubricating oil 6 ijcpe vol.14 no.3 (september 2013) -available online at: www.iasj.net blends with different weight percentage of different additives have the value 0.00, and this means that there is a significant difference in the effect of adding different percentage of detergent. table 5, total base number (tbn, mg of koh/g) of blend oils no. w t% o f d e te rg e n t in t h e o il b la n k o il w it h o v e rb a se d m g c a p ry la te ( c 8 ) o il w it h o v e rb a se d m g c a p ra te (c 1 0 ) o il w it h o v e rb a se d m g la u ra te ( c 1 2 ) o il w it h o v e rb a se d m g m y ri st a te ( c 1 4 ) o il w it h o v e rb a se d m g p a lm it a te ( c 1 6 ) o il w it h o v e rb a se d m g o le a te ( c 1 8 :1 ) o il w it h o v e rb a se d m g st e a ra te ( c 1 8 :0 ) 1. 1 0.87 1.63 1.41 1.63 1.66 1.69 1.71 2.84 2. 2 0.87 1.28 2.34 2.7 2.74 2.9 4.93 4.85 3. 3.5 0.87 4.9 5.6 5.8 5.9 8.8 10.4 10.9 4. 5 0.87 6.8 7.55 10.38 12.8 15.9 24.5 20.6 table 6, the effect between subjects and summarized anova. source sum of squares degree of freedom mean square f-value significa nt corrected model 167.467 6 27.911 0.745 0.620 carbon compound 167.467 6 27.911 0.745 0.620 correlated model 641.647 3 213.882 16.396 0.000 weight added 641.647 3 213.882 16.396 0.000 fig.s (3) and (4) show the tbn and efficiency of oil blends with prepared overbased magnesium fatty acid (c8– c18) detergents respectivly. these figures show that the overbased magnesium palmitate (c16) , stearate (c18:0) and oleate (c18:1) detergents give the higher tbn and efficiency. since the cost of oleic acid is higher than palmitic and stearic acids, they can be recommended for lubricant oil detergent preparation. usually the excepted percentage of detergent used for engine crankcase lubricants is not less than 2% [19]. for further, evaluation of the selected overbased magnesium palmitate and overbased magnesium stearate, the base oil (60 stock) as well as its blends with 2% by weight of detergents were subjected to severe oxidation condition in the presence of a soluble iron and copper catalyst at 120 ο c for 164 hours while being subjected to a constant one-liter/hour flow of oxygen. fig. 3 the tbn of oil blends with prepared overbased magnesium fatty acid (c8–c18) detergents at different weight percentages results given in table (7) show that the blends with 2% by weight overbased mg-palmitate (c16) or overbased mg-stearate (c18:0) have higher oxidation stability compared with the blend of the same oil with abdul halim a-k mohammed, mohammed r. ahmad and zainab a. k. al-messri -available online at: www.iasj.net ijcpe vol.14 no.3 (september 2013) 7 standard antioxidant used by midland refineries company. overbased detergents, especially organo-alkaline earth salt compounds, are type of metal deactivators antioxidants, which act as film-forming agents in two ways. first, they coat the metal surface, thus preventing metal ions from entering the oil. second, they minimize corrosive attack of the metal surface by physically restricting access of the corrosive species to the metal surface [3]. thus, the overbased magnesium palmitate and overbased magnesium stearate, can show an antioxidant effect, because the carbonate in their structure performs acid neutralization, and the linear structure of the soap forms the protective surface film. fig. 4 the efficiency of oil blends with prepared overbased magnesium fatty acid (c8– c18) detergents table 7, oxidation stability results characterization blank oil with overbased mg-palmitate (c16) oil with overbased mg-stearate (c18:0) standard volatile acidity, mg of koh/g 0.0025 0.0037 0.0037 0.0060 soluble acidity, mg of koh/g 0.2571 0.04939 0.01234 0.1230 total acidity, mg of koh/g 0.259 0.05309 0.01604 0.1290 total sludge, wt% 0.280 0.01114 0.00 0.0880 total oxidation products (top %) 0.363 0.0281 0.05146 0.1298 conclusions 1. a series of overbased magnesium fatty acids (c8-c18:0 and c18:1) were synthesized and evaluated by blending each additive in various concentrations with 60 stock base oil, and the tbn was determined. 2. it was found that the number of carbons in the fatty acid (c8-c18) had slight effect on the tbn of the blended oil, while additive concentrations had a significant effect on the tbn of the blended oil. 3. blends of 2% of overbased magnesium palmitate and overbased magnesium stearate detergents showed better oxidation stability than the standard antioxidant supplied by midland refineries company. acknowledgment the authors acknowledge petroleum r and d center /ministry of oil for financial support. thanks are also due to midland refineries company/iraq for providing the base oils and the analyses of tbn and oxidation stability. we thank to prof. dr. issam m. a. shakir, department of chemistry, college of science, university of baghdad, for the (anova) tests, and to naeema j.lami, cardiff university, u.k., for nmr analysis. synthesis, characterization and evaluation of overbased magnesium fatty acids detergent for medium lubricating oil 8 ijcpe vol.14 no.3 (september 2013) -available online at: www.iasj.net references 1rundnick, l.r., "lubricant additives: chemistry and applications", 2 nd ed. new york, taylor and francis group, (2009). 2stepina, v., and vesely, v., "lubricants and special fluids", amsterdam: elsevier, (1992). 3rizvi, s., "a comprehensive review of lubricant chemistry, technology, selection, and design", baltimore, astm international, (2009). 4sharma, g.k. and chawla, o.p., "modeling of lubricant oil alkalinity in diesel engines," tribol. int. 21, 5, 269-274 (1988). 5 ahmed, n.s., nasser, a.m., and kamal, r.s., " influence of some compounds as antioxidants and detergents/dispersants for lube oil", journal of dispersion science and technology, 32:1067–1074, (2011) 6hudson, l.k., eastoe, j., and dowding, p.j., "nanotechnology in action: overbased nanodetergents as lubricant oil additives", advances in colloid and interface science, 123, 425–431, (2006). 7 doll, k., and erhan, s., "synthesis of carbonated fatty methyl esters using supercritical carbon dioxide", j. agric. food chem., 53, 9608-9614, (2005). 8tupotilvo, n., ostrikov, v., and kornev, a., "plant oil derivatives as additives for lubricants" chemistry and technology of fuels and oils, 42, 192-195, (2006). 9wang, m., morris, j., tonnis, b., pinnow, d., davis, j., raymer, p., and pederson, g.," screening of the entire usda castor germplasm collection for oil content and fatty acid composition for optimum biodiesel production", j. agric. food chem, 59, 9250–9256 (2011). 10wang, y.; eli, w., liu, y. and long, l. "synthesis of environmentally friendly calcium oleate detergent", ind. eng. chem. res., 47, 8561-8565, (2008). 11wang, y., eli, w., nueraimaiti, a., and liu, y." synthesis and characterization of polyol poly-12hydroxy stearic acid: applications in preparing environmentally friendly overbased calcium oleate detergent", ind. eng. chem. res., 48, 37. ( 2009). 12wang, y. and eli, w. "synthesis of biodegradable high-alkali magnesium oleate detergent", ind. eng. chem. res., 49, 2589, (2010) 13wang, y. and eli, w. "synthesis of environmentally friendly overbased magnesium oleate detergent and high alkaline dispersant/magnesium oleate mixed substrate detergent", ind. eng. chem. res., 49, 8902-8907, (2010). 14wang, y. , eli, w., zhang, l., and cai, g., "synthesis of environmentally friendly composite-metal (calcium andmagnesium) oleate detergent", ind. eng. chem. res., 50, 1530– 1535,( 2011). 15silverstein, r. m., websters, f.x., and kiemle, d.j, “spectrometic identification of organic compounds", 7 th ed., new york, john wiely and sons, (2005). 16lu, y., and miller, j.d., "carboxyl stretching vibrations of spontaneously adsorbed and lbtransferred calcium carboxylates as determined by ftir internal reflection", spectroscopy journal of colloid and interface science,256,1,41-52,( 2002). 17 crews, p., rodriguez, j. and jaspars, m., "organic structures analysis", new york, (1998). 18wang, y. and eli, w.," recent advances in colloidal lubricant detergents" china petroleum abdul halim a-k mohammed, mohammed r. ahmad and zainab a. k. al-messri -available online at: www.iasj.net ijcpe vol.14 no.3 (september 2013) 9 processing and petrochemical technology, 12, 7-12,(2010). 19eglin, m., (2003),"development of combinational approach to lubricant additive characterization", ph.d. thesis, swiss federal institute of technology, zurich. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol. 24 no.2 (june 2023) 113 – 122 eissn: 2618-0707, pissn: 1997-4884 *corresponding author: name: mohammed thamer jaafar, email: mohammed.thamer@uokerbala.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. synthesis of novel porphyrin derivatives and investigate their application in sensitized solar cells mohammed thamer jaafar a, b, *, luma majeed ahmed b, and rahman tama haiwal b a department of petroleum engineering, college of engineering, kerbala university, karbala, iraq b department of chemistry, college of science, kerbala university, karbala, iraq abstract solar energy has significant advantages compared to conventional sources such as coal and natural gas, including no emissions, no need for fuel, and the potential for installation in a wide range of locations with access to sunlight. in this investigation, heterocyclic derivatives were synthesized from several porphyrin derivatives (4,4',4",4"'-(porphyrin-5,10,15,20-tetrayl) tetra benzoic acid) compound (3), obtained by reaction pyrrole with 4-formyl benzoic acid. subsequently, porphyrin derivative-component amides 5a, 5b, and 5c were produced by reacting compound (3) with amine derivatives at a 1:4 molar ratio. these derivatives exhibited varying sensitivities for utilization in solar cells, with compound 5a displaying the highest power conversion efficiency (pce) at 1.37%, as determined by measuring the short circuit current (jsc), open-circuit voltage (voc), and fill factor (ff) (jsc = 2.24 ma cm-2, voc = 0.80 mv, ff = 76.5%). meanwhile, compound 5c exhibited the lowest pce at 0.94% (jsc = 1.55 ma cm-2, voc = 0.750 mv, ff = 76.4%). keywords: synthesis porphyrin, porphyrin derivatives, power conversion efficiency, solar cells. received on 28/02/2023, received in revised form on 05/04/2023, accepted on 06/04/2023, published on 30/06/2023 https://doi.org/10.31699/ijcpe.2023.2.13 1introduction greek porphyria, which means purple, is the source of the term porphyrin. they belong to a vast family of highly colored pigments with a substituted aromatic macrocycle ring that is either natural or synthetic in origin and are composed of four pyrrole rings connected by four methine bridges [1–6]. the study of porphyrins has recently attracted more and more attention. porphyrins are utilized in a wide range of devices and applications, including optoelectronic, luminescent, and molecular logic ones, photonic materials, solar energy harvesting systems, supramolecular self-assembly, and medicines. the porphyrins' various electrochemical and photophysical characteristics, as well as the exocyclic substituents on the macrocycle's capacity to fine-tune these properties, have an impact on these applications [7–11]. porphyrins have a wide variety of beneficial properties, some of which include high stability, strong photon absorption, a highly conjugated plane, and a little energy difference exists between the lowest unoccupied molecular orbital (lumo) and highest occupied molecule orbital (homo). these are just a few examples of the benefits that porphyrins offer. a porphyrin has an appropriate quantity of electrons due to its highly conjugated -electron skeleton and transitions often result in substantial absorption in the uv and visible range [12– 15]. despite the abundance of described procedures, it is still difficult to synthesize porphyrins with specified functional patterns. separations, purifications, and the scarcity of acceptable precursors all add to the challenges. despite reports of synthetic approaches to different porphyrins, there is currently no supply of porphyrin building blocks with certain peripheral substituents [16– 18]. the solar cell, a promising source of renewable energy that transforms sunlight into electricity, has great promise for helping to address humanity's ongoing energy crisis. due to its multiple benefits, including its capability to operate in an acoustically tranquil setting, and its absence of toxicity or greenhouse gas emissions, the field of solar energy technology is currently experiencing significant expansion. as opposed to other photovoltaic devices, dyesensitized solar cells (dsscs) stand out among other solar cells due to their tall efficiency, inexpensive, straightforward manufacturing processes, environmental friendliness, transparency, and excellent flexibility. although dsscs outperform conventional solar cells in the lab, their commercial applicability is determined by factors including efficiency, longevity, and cost. traditional dsscs are made up of a variety of important parts, the most essential of which are a nanocrystalline semiconductor oxide, a dye sensitizer, a redox electrolyte, and a counter electrode. traditional dsscs also include other elements. to lower manufacturing costs and achieve excellent cell performance, in-depth research on the http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:mohammed.thamer@uokerbala.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2023.2.13 m. t. jaafar et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 113 122 114 individual dssc components has recently been carried out. the performance of the cell is influenced by a variety of variables, including surface shape, particle size, tio2 photoelectrode thickness, and dye type. utilizing liquid electrolytes, a total solar conversion efficiency of more than 12% has been attained [19–22]. however, using liquid electrolytes in dsscs has many drawbacks, including restricted solubility of inorganic salts like ki, nai, and lii, electrode corrosion, and shortterm stability owing to organic solvent evaporation and leakage. in order to facilitate the reduction process (i-/i-3), the counter electrode, which receives its charge from the photo-oxidized dye, injects electrons into the electrolytes. conventional conductive glasses, such as indiumor fluorine-doped tin oxide, provide a poor rate of reduction for the counter electrode in the absence of a catalyst; as a result, the counter electrode must be coated with a catalytic substance to speed up the process. due to its better conductivity and strong electrocatalytic activity, platinum (pt) is favored in this respect. however, because of the corrosive i-/i-3 redox electrolyte and the slow dissolution of platinum, which reduces its long-term stability, platinum is a highly costly, rare noble metal. these limitations prevent pt electrodes from being used extensively in dsscs. therefore, it is crucial to create substitute noble-metal-free materials that can take the place of platinum as an electrocatalyst. it is feasible to achieve a high-power conversion efficiency with a very thin platinum film of 2 nm since the power conversion efficiency of dsscs does not grow proportionally to an increase in the thickness of the platinum film [23–26]. as novel compounds, they have demonstrated success as photovoltaic materials by exhibiting responsiveness to solar cells. the achieved results indicate favorable prospects for utilizing newly synthesized porphyrin-based compounds in conjunction with tio2 paste as an anode material. this work focused on the synthesis of some new substituted porphyrin derivative compounds (3) that start from pyrrole with 4-forms benzoic acid and preparing amides derivatives from compound (3). the characterization of all prepared compounds will do and then test them as solar cells. 2experimental part 2.1. material and instruments the chemicals employed in this investigation were procured from a variety of manufacturers, including sigma aldrich, and were utilized directly without any additional purification. to verify the identity of the resulting compounds, melting points were precisely determined utilizing a digital electro thermal stuart smp-30. fourier transform infrared spectroscopy (shimadzu ftir-8400s) was conducted and reported in cm-1 units. nuclear magnetic resonance spectra were obtained in dmso-d6 using a bruker spectrometer, operating at 500 mhz for 1h nmr and 125 mhz for 13c nmr. esi-mass spectra were obtained using an agilent technology (hp) instrument with electron ionization at 70 ev. 2.2. preparation and spectral characterization of porphyrin derivatives 2.2.1. synthesis of 4,4',4",4"'-(porphyrin-5,10,15,20tetrayl) tetra benzoic acid (3) pyrrole (4 mol) was added to a solution of substituted aldehyde (4-formyl benzoic acid) (4 mol) in propionic acid (20 ml), and the reaction mixture was refluxed for one hour in the dark after that. after that, the solution was filtered and washed with hot water. 2.2.2. preparation of porphyrin derivatives 5a-c (general procedure) 1 mmol of socl2 was added to 1 mmol of 4,4’,4’’,4’’’-(porphyrin-5,10,15,20-tetrayl) tetra benzoic acid (tcpp). the mixture was stirred at 70 rpm for 30 minutes at environmental temperature, then dmf (5ml) was added with continuous stirring at the same temperature. the final solution was transferred to a round bottom flask volume (25 ml), 4 mmol of amines (a-c) were added to the last solution with reflex at 120 oc for (2-3) hours, and then 8 mmol of triethylamine (et3n) was added with continuous reflex at 120 oc for 1huore. the black solution was added to ice crystal, filtration, and washed with ethanol. 2.3. fabrication of the working electrodes (we) isopropanol and acetone were applied to the fluorinedoped tin oxide (fto) glass slides for a total of 10 minutes to fully clean them. all cleaned substrates are then diw washed and dried using a hot air stream. tio2 was used as an electrode in the fabrication of dsscs, together with other photoanode materials. every time, the paste produced from the photoanode materials was applied to the fto substrates together with 0.2 g of tio2 with 0.4 ml of (0.1 m) hno3, and one drop of triton x100 (c34h62o11, m.wt. 646.67 g/ mol) in order to achieve the thin and symmetrical thickness indicated in fig. 1, the produced paste is applied to an fto-glass substrate using a glass rod. the sample is then dried for 10 minutes at 80 oc. in order to avoid dye photodegradation, the produced samples were then submerged in a porphyrin derivativecompensated amide solution for 2 hours in the dark after being annealed for 3 hours at 220 °c. the surface of the photoanode materials was cleaned with ethanol absolute to remove non-absorbed dye molecules [27]. finally, as demonstrated in fig. 2, the graphite electrode is created by employing a candle flame on a spotless fto glass surface [28]. 2.4. preparation of the counter electrode (ce) a drop of (0.1m) iodine solution was added between two prepared electrodes. a (0.1 m) iodine solution was m. t. jaafar et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 113 122 115 prepared by combining 3.175 g of iodine (i2) with 10 g of potassium iodide (ki) in 25 ml of absolute ethanol. the solution is then maintained in an opaque container after shaking the flask until the iodine has fully dissolved [29]. in order to prevent the solution from leaking beyond the designated cell region, the counter electrode is then put on the working electrode and the solution is retained in an opaque container [30]. the j-v curve was used to compute the open-circuit voltage (voc) and short-circuit current (jsc). the following equations were used to calculate the solar cells' efficiency and fill factor (ff) [31, 32]. 𝐹𝐹 = 𝐽𝑚𝑎𝑥 𝑉𝑚𝑎𝑥 𝐽𝑆𝐶 𝑉𝑜𝑐 (1) 𝜂 = 𝐽𝑠𝑐 𝑉𝑜𝑐 𝐹𝐹 𝐼𝑜 (2) where io is the total incident irradiance, vmax is the solar cell's maximum power point voltage, and jmax is the maximum power point current. fig. 1. fto glasses fixed with medical tape fig. 2. (a) fto glasses with dye and (b) graphite counter electrode 3results and discussion 3.1. synthesis and spectroscopic characterization of the porphyrin derivatives the product compound (3) as shown in fig. 3 was diagnosed using the infrared spectrum by the appearance of nh, oh, and co groups in carboxylic acid at radii of 3371, 3300, and 1674 cm-1, respectively. the 1h-nmr spectra of compound 3 showed a singlet signal at -2.29 (2h), which can be attributed to the n-h in the pyrrole group. the compound (3) was characterized by various techniques like ft-ir, 1h-nmr, and mass spectroscopy (fig. 4 – fig. 6). fig. 3. scheme of produced of compound (3) (3) 4,4',4",4"'-(porphyrin-5,10,15,20-tetrayl) tetra benzoic acid color: black powder: yield 21%, mp > 350°c rf =0.85 (n-hexane/ethyl acetate) ft-ir (kbr, cm1):3371(nh),3300-2400(oh),3043(c-h aromatic),1674(c=o), 1604 (c=n), 1573 (c=c),.1h nmr (500mhz, dmso-d6) 𝛿h (ppm): 12.91(s,4hcooh), 8.41-8.79(d, j = 7.6 hz pyrrole-8h),). 7.13-8.38 (m, 16 ph-h), -2.29 (s,2nh), 13c nmr (500mhz, dmso-d6) δ c 122.25,126.64,126.92,129.53,129.55, 130.57,130.57,130.61130.63,138.03,139.17,143.88,147.6 5,168.1 4., uv-vis. spectrum: (𝜆max), 419 nm.); ei–ms calcd exact mass (c48h30n4o8), 790.77; found, 790.6. the second step involved the reaction of compound (3) with a variety of amines to obtain (5a-c), as explained in fig. 7. these compounds were investigated using the infrared spectrum by disappearing the carbonyl group and appearing the amide group. the experimental part provides all of the porphyrin derivatives' complete spectrum information (ms, ft-ir, 1 h, and 13c nmr), as well as melting points. compound (3) was reacted with a variety of amines in the second step to produce compound (5a-c), as displayed in fig. 7. using an infrared spectrum, these compounds were identified by the disappearance of the oh in carboxylic acid (3300) cm-1 and the appearance of the amide group (3420) cm-1. the experimental section gives comprehensive spectral data (ms, ft-ir, 1h, and 13c nmr) and melting points for all porphyrin derivatives. all the new compounds were characterized by various techniques like ft-ir and 1h-nmr mass spectroscopy (fig. 8 – fig. 12). (5-a) 4,4',4'',4'''-(porphyrin-5,10,15,20-tetrayl) tetrakis(n(benzo[d]thiazol-2-yl) benzamide) color: black powder: yield 80%, mp > 350°c ft-ir (kbr, cm-1):3425(nh stretch),3055(c–h aromatic),1701(c=o), 1608 (c=n),1489(c=c), 636(cs)., 1hnmr (500mhz, dmso-d6): 𝛿h (ppm): 10,51 (s,4h-conh), 8.66-8.11 (m 8h pyrrole-h), 8.09-7.97 (m, 8 ar-h,),7.84-7.87(m, 8 ar-h), 7.71 (d, j = 8.1 hz, 4h ar-h), 7.45-7.16 (m 12h ar-h), -2.29 (s,2nhint)., 13c nmr (500 mhz, dmso-d6) δ c 120.03,120.93,122.2, 123.60,125.64,126.64,126.92,129.43,129.52,129.54,130.6 1,130.64,130.71,132.15,138.01,138.72,139.35,143.88,147 .65,150.32,156.83,159.77,166.95., uv-vis. spectrum: (𝜆max), 417nm.; anal.calcd for (c76h46n12o4s4): c, 69.18; h, 3.51; n, 12.74; o, 4.85; s, 9.72 found c, 69.01; (a) (b) m. t. jaafar et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 113 122 116 h, 3.32; n, 12.48 %.,ei–ms calcd exact mass 1319.52; found, 1319.5. (5-b) 4,4',4'',4'''-(porphyrin-5,10,15,20-tetrayl) tetrakis(n(1h-benzo[d]imidazol-2-yl) benzamide) color: black powder: yield 82%, mp > 350°c ft-ir (kbr, cm-1):3421(nh stretch),3036 (c–h aromatic),1705(c=o), 1624 (c=n),1485(c=c)., 1hnmr (500mhz, dmso-d6): 𝛿h (ppm): 11.37 (s,4nh), 10.69 (s,4h-conh), 8.86 -8.37 (m,8 pyrrole-h), 8.10-7.12 (m, 32h ar-h), -2.25 (s,2nh pyrrole), anal.calcd for (c76h50n16o4): c, 72.95; h, 4.03; n, 17.91; found c, 72.60; h, 4.21; n, 17.70 %., esi–ms calcd exact mass 1251.34; found, 1251.22. (5-c) 4,4',4'',4'''-(porphyrin-5,10,15,20-tetrayl) tetrakis(n(4-carbamoylphenyl) benzamide) color: black powder: yield 84%, mp > 350°c ft-ir (kbr, cm-1): 3420-3395-(nh2), 3290 (nh), 3059 (c–h aromatic), 1697(c=o), 1600 (c=n),1484c=c),.1hnmr (500mhz, dmso-d6): 𝛿h (ppm): 9.84 (s,4h-conh), 8.67-8.64 (m, 8 pyrrole-h), 8.15-7.31 (m, 32h ar-h), 0693 (s,8nh2), 1.99 (s,2nh)., anal.calcd for (c76h54n12o8): c, 72.26; h, 4.31; n, 13.30; o, 10.13; found c, 72.02; h, 4.15; n, 13.12%. fig. 4. ft-ir spectrum of compound (3) fig. 5. 1hnmr spectrum of compound (3) m. t. jaafar et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 113 122 117 fig. 6. mass spectrum of compound (3) fig. 7. scheme of prepared compounds 5a, 5b, and 5c fig. 8. ft-ir spectrum of compound (5a) m. t. jaafar et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 113 122 118 fig. 9. 1hnmr spectrum of compound (5a) fig. 10. ft-ir spectrum of compound (5b) fig. 11. 1hnmr spectrum of compound (5b) m. t. jaafar et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 113 122 119 fig. 12. 1hnmr spectrum of compound (5c) 3.2. dsscs test findings jsc, voc, ff, and pce are shown in fig. 13 together with the j-v curves for all produced compounds (table 1). based on the results in table 1, the increased efficiencies (𝜂) for using prepared compounds are sequenced 𝜂5𝑎 > 𝜂5𝑏 > 𝜂5𝑐 .the efficiency of using compound 5a is large due to have it thiazole group, which is rich in electrons (n-s) that will inject lone pair electrons to lumo of tio2. on the other hand, compound 5b has an imidazole group (n-h) that has fewer lone pair electrons compared with compound 5a. fig. 13. j-v curve of dsscs sensitized by 5a,5b and 5c table 1. photovoltaic characteristics for all colors in a typical environment dye )2-(ma.cm scj (mv) ocv ff (%) pce (%) 5a 2.24 0.806 76.5 1.3756 5b 2.01 0.775 76.6 1.2325 5c 1.55 0.750 76.4 0.9470 4conclusion this work is summarized: 1a series of porphyrin derivatives were used as sensitized in solar cells after adsorbed on the tio2 paste surface. this paste was poured on the fto surface using triton x-100 as linked material. all prepared derivatives were given the sensitivity to work as solar cells. 2 the maximum efficiency value was found for using derivative 5a which generates a power conversion efficiency (pce) of 1.37%. 3 the 5c compound has the lowest pce value 0.94% and that may be attributed to the smallest optical energy gap about (2.2ev) when compared to other prepared compounds. references: [1] h. lin et al., “preparation of single substituted phenyl porphyrins form meso-tetraphenyl porphyrin-synthetic example from symmetric porphyrin into asymmetric porphyrins,” open j inorg chem, vol. 08, no. 01, pp. 21–27, 2018, https://doi.org/10.4236/ojic.2018.81002 [2] w. lian, y. sun, b. wang, n. shan, and t. shi, “synthesis and properties of 5,10,15,20-tetrakis [4(3,5-dioctyloxybenzamido) phenyl] porphyrin and its metal complexes,” journal of the serbian chemical society, vol. 77, no. 3, pp. 335–348, 2012, https://doi.org/10.2298/jsc110516190l [3] p. i. premovi, i. r. tonsa, d. m., and m. s. pavlovi, “air oxidation of the kerogen/asphaltene vanadyl porphyrins: an electron spin resonance study,” journal of the serbian chemical society, volume 65, issue 2, pages: 113-121 2000. https://doi.org/10.2298/jsc0002113p https://doi.org/10.4236/ojic.2018.81002 https://doi.org/10.2298/jsc110516190l https://doi.org/10.2298/jsc0002113p m. t. jaafar et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 113 122 120 [4] r. k. lammi et al., “structural control of photoinduced energy transfer between adjacent and distant sites in multiporphyrin arrays,” j am chem soc, vol. 122, no. 31, pp. 7579–7591, aug. 2000, https://doi.org/10.1021/ja001031x [5] o. m. opeyemi, h. louis, c. i. opara, o. o. funmilayo, and t. o. magu, “porphyrin and phthalocyanines-based solar cells: fundamental mechanisms and recent advances,” advanced journal of chemistry-section a, 2(1), 21-44 2019. https://doi.org/10.29088/sami/ajca.2019.2.2144 [6] k. sakamoto and e. ohno-okumura, “syntheses and functional properties of phthalocyanines,” materials, vol. 2, no. 3, pp. 1127–1179, 2009, https://doi.org/10.3390/ma2031127 [7] j. l. suk, j. t. hupp, and s. b. t. nguyen, “growth of narrowly dispersed porphyrin nanowires and their hierarchical assembly into macroscopic columns,” j am chem soc, vol. 130, no. 30, pp. 9632–9633, jul. 2008, https://doi.org/10.1021/ja801733t [8] e. önal, “matériaux moléculaires magnétiques à base de porphyrines,” université claude bernard-lyon i, 2014. [9] h. kim, r. manivannan, g. heo, j. w. ryu, and y. a. son, “porphyrin dye/tio2 entrenched in pet to attain self-cleaning property through visible light photocatalytic activity,” research on chemical intermediates, vol. 45, no. 7, pp. 3655–3671, jul. 2019, https://doi.org/10.1007/s11164-019-03813-4 [10] a. m. shultz, o. k. farha, j. t. hupp, and s. b. t. nguyen, “synthesis of catalytically active porous organic polymers from metalloporphyrin building blocks,” chem sci, vol. 2, no. 4, pp. 686–689, 2011, https://doi.org/10.1039/c0sc00339e [11] k. zhang, y. yu, s. t. nguyen, j. t. hupp, l. j. broadbelt, and o. k. farha, “epoxidation of the commercially relevant divinylbenzene with [tetrakis(pentafluorophenyl)porphyrinato] iron(iii) chloride and its derivatives,” ind eng chem res, vol. 54, no. 3, pp. 922–927, jan. 2015, https://doi.org/10.1021/ie504550p [12] a. heydari-turkmani and s. zakavi, “the first solid state porphyrin-weak acid molecular complex: a novel metal free, nanosized and porous photocatalyst for large scale aerobic oxidations in water,” j catal, vol. 364, pp. 394–405, aug. 2018, https://doi.org/10.1016/j.jcat.2018.06.011 [13] y. ding, w. h. zhu, and y. xie, “development of ion chemosensors based on porphyrin analogues,” chem rev, vol. 117, no. 4, pp. 2203–2256, feb. 2017, https://doi.org/10.1021/acs.chemrev.6b00021 [14] m. jurow, a. e. schuckman, j. d. batteas, and c. m. drain, “porphyrins as molecular electronic components of functional devices,” coordination chemistry reviews, vol. 254, no. 19–20. pp. 2297– 2310, oct. 2010. https://doi.org/10.1016/j.ccr.2010.05.014 [15] w. j. cho, y. cho, s. k. min, w. y. kim, and k. s. kim, “chromium porphyrin arrays as spintronic devices,” j am chem soc, vol. 133, no. 24, pp. 9364–9369, jun. 2011, https://doi.org/10.1021/ja111565w [16] p. zhang, m. wang, c. li, x. li, j. dong, and l. sun, “photochemical h2 production with noblemetal-free molecular devices comprising a porphyrin photosensitizer and a cobaloxime catalyst,” chemical communications, vol. 46, no. 46, pp. 8806–8808, dec. 2010, https://doi.org/10.1039/c0cc03154b [17] m. noori et al., “tuning the electrical conductance of metalloporphyrin supramolecular wires,” sci rep, vol. 6, nov. 2016, https://doi.org/10.1038/srep37352 [18] m. adineh, p. tahay, m. ameri, n. safari, and e. mohajerani, “fabrication and analysis of dyesensitized solar cells (dsscs) using porphyrin dyes with catechol anchoring groups,” rsc adv, vol. 6, no. 18, pp. 14512–14521, 2016, https://doi.org/10.1039/c5ra23584g [19] n. santhanamoorthi, c. m. lo, and j. c. jiang, “molecular design of porphyrins for dye-sensitized solar cells: a dft/tddft study,” journal of physical chemistry letters, vol. 4, no. 3, pp. 524– 530, feb. 2013, https://doi.org/10.1021/jz302101j [20] m. r. samantaray et al., “synergetic effects of hybrid carbon nanostructured counter electrodes for dyesensitized solar cells: a review,” materials, vol. 13, no. 12. mdpi ag, pp. 1–34, jun. 02, 2020. https://doi.org/10.3390/ma13122779 [21] g. e. zervaki et al., “a propeller-shaped, triazinelinked porphyrin triad as efficient sensitizer for dyesensitized solar cells,” eur j inorg chem, no. 6, pp. 1020–1033, 2014, https://doi.org/10.1002/ejic.201301278 [22] xavier a. jeanbourquin, xiaoe li, chunhung law, piers r.f. barnes, robin humphry-baker, peter lund, muhammad i. asghar, and brian c. o’regan . rediscovering a key interface in dye-sensitized solar cells: guanidinium and iodine competition for binding sites at the dye/electrolyte surface. journal of the american chemical society 2014, 136 (20) , 7286-7294. https://doi.org/10.1021/ja411560s [23] h. gerischer, m.e. michel-beyerle, f. rebentrost, h. tributsch, sensitization of charge injection into semiconductors with large band gap, electrochimica acta, 13(6),1968, 1509-1515, https://doi.org/10.1016/0013-4686(68)80076-3 [24] s. sharma, bulkesh siwach, s. k. ghoshal, and d. mohan, “dye sensitized solar cells: from genesis to recent drifts,” renewable and sustainable energy reviews, vol. 70. elsevier ltd, pp. 529–537, apr. 01, 2017. https://doi.org/10.1016/j.rser.2016.11.136 [25] s. kannan balasingam, m. lee, m. gu kang, and y. jun, “improvement of dye-sensitized solar cells toward the broader light harvesting of the solar spectrum,” chemical communications, vol. 49, no. 15, pp. 1471–1487, jan. 2013, https://doi.org/10.1039/c2cc37616d https://doi.org/10.1021/ja001031x https://doi.org/10.29088/sami/ajca.2019.2.2144 https://doi.org/10.3390/ma2031127 https://doi.org/10.1021/ja801733t https://theses.hal.science/tel-01214515/ https://theses.hal.science/tel-01214515/ https://theses.hal.science/tel-01214515/ https://doi.org/10.1007/s11164-019-03813-4 https://doi.org/10.1039/c0sc00339e https://doi.org/10.1021/ie504550p https://doi.org/10.1016/j.jcat.2018.06.011 https://doi.org/10.1021/acs.chemrev.6b00021 https://doi.org/10.1016/j.ccr.2010.05.014 https://doi.org/10.1021/ja111565w https://doi.org/10.1039/c0cc03154b https://doi.org/10.1038/srep37352 https://doi.org/10.1039/c5ra23584g https://doi.org/10.1021/jz302101j https://doi.org/10.3390/ma13122779 https://doi.org/10.1002/ejic.201301278 https://doi.org/10.1021/ja411560s https://doi.org/10.1016/0013-4686(68)80076-3 https://doi.org/10.1016/j.rser.2016.11.136 https://doi.org/10.1039/c2cc37616d m. t. jaafar et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 113 122 121 [26] m. r. s. a. janjua et al., “theoretical and conceptual framework to design efficient dye-sensitized solar cells (dsscs): molecular engineering by dft method,” j clust sci, vol. 32, no. 2, pp. 243–253, mar. 2021, https://doi.org/10.1007/s10876-02001783-x [27] m. q. lokman et al., “enhancing photocurrent performance based on photoanode thickness and surface plasmon resonance using ag-tio2 nanocomposites in dye-sensitized solar cells,” materials, vol. 12, no. 13, jul. 2019, https://doi.org/10.3390/ma12132111 [28] u. i. ndeze, j. aidan, s. c. ezike, and j. f. wansah, “comparative performances of nature-based dyes extracted from baobab and shea leaves photosensitizers for dye-sensitized solar cells (dsscs),” current research in green and sustainable chemistry, vol. 4, jan. 2021, https://doi.org/10.1016/j.crgsc.2021.100105 [29] m. halka, s. smoleń, i. ledwożyw-smoleń, and w. sady, “comparison of effects of potassium iodide and iodosalicylates on the antioxidant potential and iodine accumulation in young tomato plants,” j plant growth regul, vol. 39, no. 1, pp. 282–295, mar. 2020, https://doi.org/10.1007/s00344-01909981-2 [30] c. longo and m.-a. de paoli, “dye-sensitized solar cells: a successful combination of materials,” 2003. https://doi.org/10.1590/s010350532003000600005 [31] s. umale, v. sudhakar, s. m. sontakke, k. krishnamoorthy, and a. b. pandit, “improved efficiency of dssc using combustion synthesized tio2,” mater res bull, vol. 109, pp. 222–226, jan. 2019, https://doi.org/10.1016/j.materresbull.2018.09.044 [32] n. kutlu, “investigation of electrical values of lowefficiency dye-sensitized solar cells (dsscs),” energy, vol. 199, may 2020, https://doi.org/10.1016/j.energy.2020.117222 https://doi.org/10.1007/s10876-020-01783-x https://doi.org/10.1007/s10876-020-01783-x https://doi.org/10.3390/ma12132111 https://doi.org/10.1016/j.crgsc.2021.100105 https://doi.org/10.1007/s00344-019-09981-2 https://doi.org/10.1007/s00344-019-09981-2 https://doi.org/10.1590/s0103-50532003000600005 https://doi.org/10.1590/s0103-50532003000600005 https://doi.org/10.1016/j.materresbull.2018.09.044 https://doi.org/10.1016/j.energy.2020.117222 m. t. jaafar et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 113 122 122 ةلحساستخليق مشتقات البورفيرين الجديدة والتحقق من تطبيقها في الخاليا الشمسية ا 2رحمن طعمه هيول و ، 2، لمى مجيد احمد *، 2، 1محمد ثامر جعفر ، كلية الهندسة ، جامعة كربالء ، كربالء ، العراق نفطقسم هندسة ال 1 قسم الكيمياء ـ كلية العلوم ـ جامعة كربالء ـ كربالء ـ العراق 2 الخالصة الفحم والغاز الطبيعي، بما في ذلك عدم تمتلك الطاقة الشمسية مزايا هامة مقارنة بالمصادر التقليدية مثل وجود انبعاثات وعدم الحاجة إلى وقود وإمكانية التركيب في مجموعة واسعة من المواقع التي تتوفر فيها أشعة " 4"، 4'،4،4الشمس. وفي هذه الدراسة، تم تحضير مشتقات حلقية غير متجانسة من عدة مشتقات بورفيرين ) ، التي تم الحصول عليها بتفاعل بيرول 3تترايل( تترا حمض البنزويك( مركب -5،10،15،20-)بورفيرين -' من خالل 5c، و 5a ،5bفورميل. وفيما بعد، تم إنتاج مشتقات بورفيرين الجزيئية -4-مع حمض البنزويك . وقد أظهرت هذه المشتقات حساسيات متفاوتة 4: 1مع مشتقات األمين بنسبة مولية 3تفاعل المركب ٪، 1.37بنسبة (pce) أعلى كفاءة تحويل الطاقة 5aخدام في الخاليا الشمسية، حيث عرض المركب لالست = jsc) ، وعامل الملء(voc) ، والجهد الدائري المفتوح(jsc) طريق قياس التيار القصير الدائر وذلك عن ) ff) (2.24 0.80 ، 2مللي أمبير / سمvoc = 76.5، فولتff = 5المركب ٪ بينما عرض c أدنى , .ff فولت = 0.750voc ، 2مللي أمبير / سم = pce 1.55jsc =0.94 ٪ كفاءة تحويل بنسبة = 76.4٪. ، الخاليا الشمسية.، كفاءة تحويل الطاقة، مشتقات البورفيرينتخليق البورفيرين :دالةالكلمات ال available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.23 no.2 (june 2022) 43 – 46 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: ghanim m. farman, email: ghanimzubaidy@uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. determining optimum oil separator size and optimum operating pressure ghanim m. farman university of baghdad, college of engineering, petroleum engineering department. abstract the optimum separators operating pressure is determined by using flash calculations and equilibrium ratios. in this study, the optimum separator size for jambur field is calculated by using equations introduced by arnold and stewart and api12j specific ation [1]. because jambur field has a high production rate two conditions are taken in the study to determine separator size, first based on production rate 80,000 bbl/day and second based on split the production between two banks a and b (40,000 bbl/day for each ba nk). the calculation resulted in optimum separator pressure for the first stage of 700 psi, and the second stage of 300 psi, and the third stage of 120 psi. the results show that as the number of stages increased above three-stage for jambur field less incremental liquid recovery achieved and this will not cover the cost of adding an extra stage. keywords: flash evaporation, insulators, chemical composition received on 24/02/2022, accepted on 02/05/2022, published on 30/06/2022 https://doi.org/10.31699/ijcpe.2022.2.6 1introduction when oil flows from a well with high pressure and temperature, it is subjected to a decrease in temperature and pressure. the gases are released from the fluids and the character of the well stream changes. the gas velocity carries liquid drops, and the liquid carries gas bubbles. separating materials to these stages is one of the essential processes in the treatment of oil and gas, processing and production. various studies have been managed to determine the volume of surface separators and to determine the optimal separation pressure [2]. oil separators are categorized as two-phase if they separate gas from the total liquid and three phase if they also separate the liquid stream into its water components and crude oil. jambur field is one of the producing fields in the north oil company. jambur field is located 20 km southeast of kirkuk governorate, with an area of (35 * 4.5 km). the field represents one of the structures intertwined with the fields of the kirkuk region, as it is located southeast of bay hassan and khabaz fields and along with them [3]. it is considered one of the important fields in the north oil company, but in the past few years, the field productivity has been reduced by half due to the worn-out and absence of periodic maintenance of separators which led to a significant loss in profit. in this study, the optimum separator size for the field will be calculated to take advantage of the maximum productivity of the field [4]. in the oil separator, oil and accompanied gas, because of the mixing of the accompanied water, therefore the level of oil must not be override a rang as not to be less than a proper level [5]. ken arnolds and maurice stewart [6] made a significant contribution to oil separation. they presented a set of equations obtained for application to separator size and select two phase and three phase separators types. their two researches were then appeared with other subjects in a book coverage all aspects of treatment and oil separation [6]. 2the calculation of the flash flash computations can be considered an essential part of reservoirs computation and the process engineering. they are needed whenever it’s significant to know the quantity of a liquid hydrocarbons and gas co-existing found in any reservoir or vessels at a certain pressure and temperature. it’s important to mention that such calculations are carried out to determine the structure of the current hydrocarbon phases [7]. when the general chemical composition of any hydrocarbon system at a certain pressure and temperature is given, the calculations of the flash will be used to measure: • number of moles of the vapor phase (nv). • number of moles of the liquid phase (nl). • mole fraction of the liquid phase (xi). • mole fraction of the gas phase (yi). http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:ghanimzubaidy@uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2022.2.6 tel:35.4 g. m. farman / iraqi journal of chemical and petroleum engineering 23,2 (2022) 43 46 44 3selecting optimum separator pressure one of the most critical in separation designing is determining the most favorable separator pressure. whenever the pressure of the separator is high, considerable quantities of light components will be found as a liquid and will be lost over with other important components to the gas phase at the stock tank. however, big quantities of sprightly components are separated from the liquid. therefore, they will attract considerable amounts of intermediate and heavier hydrocarbon components, if the pressure is too low [8]. the pressure, which is named the optimum separator pressure, must be selected to maximize the volume of oil buildup in the stock tank. such optimum separator pressure could also result in the followings [9]: • a maximum api gravity of the stock-tank oil. • a less oil shrinkage or minimum oil formation volume factor. • a minimum gas solubility. 4separator type selection since jambur field has a high gor ratio (1000-2000 scf/bbl) and high wellhead pressure (1000 psi) and the area are available, so two-phase horizontal separator is the best choice to deal with because it is less expensive and easy to shipping, install, and maintenance [10]. 5number of stages table 1 gives the result of flash calculations to determine the optimum number of stages for jambur field. table 1. effect of number of stages on liquid recovery number of stages* liquid recovery bbl/day total cost of equipment $ net income of selling incremental oil (after 10 years) $ 1 78700 12,456,000 2 79500 21,034,600 146,000,000 3 79932 45,700,550 78,850,000 4 80005 63,520,200 12,775,000 *excluding stock-tank table 1 shows that four stages give the highest stocktank liquid recovery but it will not cover the cost of adding an extra stage. so three-stage separation process is selected for jambur field. 6separator operating pressure by performing a flash calculation for the jambur field fluid composition that feds the first separator table 2 obtained. table 4 shows optimum separator pressure for each stage and the total gas-oil ratio, api gravity and oil formation volume factor of stock-tank oil. table 2. optimum separator pressure stage pressure , psi api gor scf/stb bo bbl/stb first 700 39.73997 986.0572 1.487687 second 300 third 120 optimum separator pressure is selected based on a maximum api gravity of stock-tank oil, minimum formation volume factor of the oil (less oil shrinkage), and minimum producing gas solubility ( producing gas oil ratio). 7separator sizing based on liquid capacity constraints and by using equations introduced by arnold and stewart separator size for each stage is obtained [11]. because jambur field has a high production rate (80,000 bbl/day), it may be better to split the production between two banks a and b. so two conditions will be taken to calculate separators size for jambur field. one minute retention time for oils has (api > 35) with no foaming tendencies proved to be sufficient (api for jambur field = 40). 1based on production rate 80,000 bbl/day: table 3 gives the result of optimum separator size calculations for each stage based on the slenderness ratio must be between 3-5 to prevent liquid re-entrainment into the vapor phase. table 3. optimum separators size for each stage stage internal diameter (inch) effective length for liquid (ft) seam-toseam length (ft) slenderness ratio first 68 19.92708848 26.56945131 4.688726702 second 66 20.34140102 27.12186803 4.931248733 third 66 19.84946871 26.46595828 4.811992415 2based on production rate 40,000 bbl/day: table 4 shows the result of separator size calculations for each stage based on slenderness ratio as mentioned previously. table 4. separators size for each stage stage internal diameter (inch) effective length for liquid (ft) seam-toseam length (ft) slenderness ratio first 60 12.79761905 17.06349206 3.412698413 second 54 15.19326867 20.25769155 4.501709234 third 54 14.82583774 19.76778366 4.392840813 g. m. farman / iraqi journal of chemical and petroleum engineering 23,2 (2022) 43 46 45 it is always better to determine the standard vessel size according to api12j specification, so: a. for the first stage separator size, api12j accepted 60-in diameter x 20-ft seam to seam length. b. for the second stage separator size, api12j accepted 54-in diameter x 20-ft seam to seam length. c. for the third stage separator size, api12j accepted 54-in diameter x 20-ft seam to seam length. 8conclusions 1for determining the separators' optimum pressure and identifying the number of stages for jambur field, different cases of pressures and the number of stages are taken. the calculations results showed that the four stage separation unit can produce 1,300 bbl/day more stabilized oil compared to the one stage separation unit. furthermore, the number of separation stages effects on the oil recovery was investigated. four cases with one, two, three, and four separators in the production unit were considered to reach the maximum oil recovery. then, economic evaluations are applied to these cases to indicate the most economic case. the results revealed that a three stage separation unit with separators operating pressure of 700 psi, 300 psi, 120 psi respectively would be more economical. 2for determining optimum separator size two cases are taken. the first case assumed that the 80,000 bbl/day fed a single bank and the second case based on that the production disturbed between two banks (40,000 bbl/day for each bank). the calculations results showed that the first case gives a separators diameter of 68in for the first stage and 66in for the second and third stage while the second case gives a smaller separators diameter (60in for the first stage and 54in for the second and third stage). engineering evaluations are applied to the two cases taking into account api 12j specification to indicate the better case. the evaluation showed that the second case more flexible and easy to operate and maintain. references [1] arnold, k. and stewart, m. surface production operations, design of oil handling systems and facilities. third edition (2008). [2] arnold, k. and stewart, m. design of oil-handling systems and facilities. gulf professional publishing, 1998. [3] raad mohammed jawad. alkhalissi, " single well coning problem andapplicable solutions”. iraqi journal of chemical and petroleum engineering. (2015). [4] kegang ling, (2013). new method to estimate surface separator optimum operating pressures. spe -163111ms. [5] a. . k. hamadi and .imad . . a.kheioon, “modeling of intelligent control system for liquid level in multistage separator arrangement in oil and natural gas industry”, utjes, vol. 9, no. 2, pp. 1–7, apr. 2019. [6] arnold, k. and stewart, m.. designing oil and gas production systems, how to size and select two phatwo-phasetors. spe reprint series (production facilities) 25: 1989, 91-96. [7] chilingarian, g.v. and beeson, c.m. ed. 1969. surface operation in petroleum production. new york: elsevier. [8] svercek, w. y. and monnery w. d. (1993). design two phase separators within the right limits. chemical engineering progress, 53-60. [9] bahadori, a., vuthaluru, h.b., and mokhatab, s.2008. optimizing separators pressures in the multistage crude oil production unit. asia-pac. j. chem. eng. 3(4): 380-386. [10] al-jawad, m.s. and hassan, o.f. 2010 a. correlating optimum stage pressure for sequential separator systems. spe proj fac & const 5 (1): 1316. spe-118225-pa. [11] ghanim m. farman, maha raouf abdulamir. "formulation of new equation to estimate productivity index of horizontal wells". iraqi journal of chemical and petroleum engineering. (2014). https://books.google.com.tr/books?hl=en&lr=&id=gvm34zk6fm8c&oi=fnd&pg=pp13&dq=%5b2%5d%09arnold,+k.+and+stewart,+m.+(2008).+surface+production+operations,+volume+2:,+third+edition%3b+design+of+gas-handling+systems+and+facilities+gulf+professional+publishing.&ots=o7sfyoig4v&sig=jz4gal2fgelfvpbrmzs8wg9fily&redir_esc=y#v=onepage&q&f=false https://books.google.com.tr/books?hl=en&lr=&id=gvm34zk6fm8c&oi=fnd&pg=pp13&dq=%5b2%5d%09arnold,+k.+and+stewart,+m.+(2008).+surface+production+operations,+volume+2:,+third+edition%3b+design+of+gas-handling+systems+and+facilities+gulf+professional+publishing.&ots=o7sfyoig4v&sig=jz4gal2fgelfvpbrmzs8wg9fily&redir_esc=y#v=onepage&q&f=false https://books.google.com.tr/books?hl=en&lr=&id=gvm34zk6fm8c&oi=fnd&pg=pp13&dq=%5b2%5d%09arnold,+k.+and+stewart,+m.+(2008).+surface+production+operations,+volume+2:,+third+edition%3b+design+of+gas-handling+systems+and+facilities+gulf+professional+publishing.&ots=o7sfyoig4v&sig=jz4gal2fgelfvpbrmzs8wg9fily&redir_esc=y#v=onepage&q&f=false https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/255 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/255 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/255 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/255 https://onepetro.org/ogf/article-abstract/2/03/65/204720/new-method-to-estimate-surface-separator-optimum https://onepetro.org/ogf/article-abstract/2/03/65/204720/new-method-to-estimate-surface-separator-optimum https://onepetro.org/ogf/article-abstract/2/03/65/204720/new-method-to-estimate-surface-separator-optimum https://jeng.utq.edu.iq/index.php/main/article/view/40 https://jeng.utq.edu.iq/index.php/main/article/view/40 https://jeng.utq.edu.iq/index.php/main/article/view/40 https://jeng.utq.edu.iq/index.php/main/article/view/40 https://pascal-francis.inist.fr/vibad/index.php?action=getrecorddetail&idt=9191692 https://pascal-francis.inist.fr/vibad/index.php?action=getrecorddetail&idt=9191692 https://pascal-francis.inist.fr/vibad/index.php?action=getrecorddetail&idt=9191692 https://pascal-francis.inist.fr/vibad/index.php?action=getrecorddetail&idt=9191692 https://pascal-francis.inist.fr/vibad/index.php?action=getrecorddetail&idt=6053626 https://pascal-francis.inist.fr/vibad/index.php?action=getrecorddetail&idt=6053626 https://pascal-francis.inist.fr/vibad/index.php?action=getrecorddetail&idt=6053626 https://onlinelibrary.wiley.com/doi/abs/10.1002/apj.159 https://onlinelibrary.wiley.com/doi/abs/10.1002/apj.159 https://onlinelibrary.wiley.com/doi/abs/10.1002/apj.159 https://onlinelibrary.wiley.com/doi/abs/10.1002/apj.159 https://onepetro.org/pfc/article-abstract/5/01/13/192130/correlating-optimum-stage-pressure-for-sequential?redirectedfrom=fulltext https://onepetro.org/pfc/article-abstract/5/01/13/192130/correlating-optimum-stage-pressure-for-sequential?redirectedfrom=fulltext https://onepetro.org/pfc/article-abstract/5/01/13/192130/correlating-optimum-stage-pressure-for-sequential?redirectedfrom=fulltext https://onepetro.org/pfc/article-abstract/5/01/13/192130/correlating-optimum-stage-pressure-for-sequential?redirectedfrom=fulltext https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/278 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/278 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/278 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/278 g. m. farman / iraqi journal of chemical and petroleum engineering 23,2 (2022) 43 46 46 تحديد الحجم وضغط التشغيل األمثل لعازالت النفط غانم مديح فرمان قسم هندسة النفط -كلية الهندسة -جامعة بغداد خالصة ال هذه في التوازن. ونسب الومضي التبخير حسابات باستخدام للعازالت األمثل التشغيل ضغط تحديد يتم ارنولد الباحثين قدمها التي المعادالت باستخدام جمبور لحقل األمثل العازلة حجم حساب يتم ، الدراسة رطين في الدراسة لتحديد حجم وستيوارت. نظًرا ألن حقل جمبور يحتوي على معدل إنتاج مرتفع ، فقد تم أخذ ش و aبرميل / يوم والثاني بناًء على تقسيم اإلنتاج بين حالتين 80،000الفاصل ، أواًل بناًء على معدل اإلنتاج b (40،000 األولى للمرحلة مثالي فاصل ضغط الحساب عن نتج حالة(. لكل يوم / / 700برميل رطل رطل / بوصة مربعة. تظهر 120بوصة مربعة ، والمرحلة الثالثة /رطل 300بوصة مربعة ، والمرحلة الثانية النتائج أنه مع زيادة عدد المراحل إلى ما يزيد عن ثالث مراحل لحقل جمبور، يتم تقليل استرداد السائل اإلضافي الذي تم تحقيقه وهذا لن يغطي تكلفة إضافة مرحلة إضافية. العازالت, التركيب الكيمياوي التبخير الومضي, :الدالة الكلمات iraqi journal of chemical and petroleum engineering vol.14 no.4 (december 2013) 1925 issn: 1997-4884 corrosion inhibition of galvanic couple copper alloy/mild steel in cooling water system aprael s. yaro and munaf a. idan chemical engineering department-college of engineering-university of baghdad-iraq abstract the driving idea for the present work was to combine the effect of polyvinyl alcohol (pva) as corrosion inhibitor with the distance between the anodic and cathodic elements of the galvanic cell, beside their area ratio, in scope of synergistic suppression of galvanic corrosion on cu/fe model couple, using weight loss method. the performance affecting galvanic corrosion process has been tested for three major factors affect the process: 1. four pva inhibitor concentrations were selected to be (0, 1000, 4000 and 7000 ppm) in simulated cooling water. 2. two cathode: anode area ratios as 1:1 and 2.4:1. 3. two distances apart cathode – anode as 3 and 7 cm. maximum corrosion inhibition achieved was 86% which indicates that increasing inhibitor concentration leads to decrease dissolution process followed hydrogen evaluation cu electrode as cathode element in galvanic cell. keywords: galvanic corrosion, mild steel, polarization, galvanic current introduction the study of inhibition mechanism, electrochemical, and kinetic behavior of water-soluble polymers such as poly vinyl alcohol as a corrosion inhibitor to protect cu-cs galvanic couple in aqueous media, contributes to the prevention of corrosion, particularly in industrial equipment which inevitably requires joining pieces of different metals for its construction [1–6]. cooling water systems are often constructed by dissimilar metals such as copper fins that cool the fluid by convection, internal copper tubes and mild steel shells. the conditions of the cleaning process during the manufacture of heavy duty heat exchangers promote the dissolution of the anodic metal in a galvanic couple especially with an unfavorable cathode-anode area ratio of 2.4 to 1.0. the use of polyvinyl alcohol as corrosion inhibitor is related to its outstanding properties. the film forming and adhesive qualities enable nearly all water-soluble polymers to find uses as binders [7, 8, 9]. galvanic corrosion, resulting from a metal contacting another conducting material in a corrosive medium, is one of the most common types of corrosion. in many cases, galvanic corrosion may result in quick deterioration, but in other cases, the galvanic corrosion of one metal may iraqi journal of chemical and petroleum engineering university of baghdad college of engineering corrosion inhibition of galvanic couple copper alloy/mild steel in cooling water system 20 ijcpe vol.14 no.4 (december 2013) -available online at: www.iasj.net result in the corrosion protection of an attacked metal, which is the basis of cathodic protection by sacrificial anode [10]. when two dissimilar conducting materials in electrical contact with each other are exposed to an electrolyte, a current, the galvanic current, flows from one to the other, galvanic corrosion is that part of the corrosion that occurs at the anodic member of such a couple and is directly related to the galvanic current by faraday’s law [11]. many factors play a role in galvanic corrosion in addition to the potential difference between the two coupled metals. depending on the circumstance. compared to normal corrosion, galvanic corrosion is generally more complex because, in addition to material and environmental factors, it involves geometrical factors [12]. experimental work 1. materials the materials of electrodes used in this investigation were 2 coupons from mild steel type sa 515 gr 60 having the following dimensions:  big coupon ( 4.9cm length ,3cm width and 0.3 cm thickness).  small coupon ( 2.83cm length , 3cm width and 0.3 cm thickness). these specimens having the following chemical compositions (% wt) (were supplied by al-dura refinery): table 1, the chemical composition of mild steel coupon (%wt) carbon manganese phosphorus sulfur silicon fe 0.24 0.9 0.035 0.035 0.15 -0.4 remainder the second electrode was copper type astm b-111-443 with 3.5 cm length, 4.43 cm width and 0.2 cm thickness having the chemical compositions as follows: table 2, the chemical composition of copper coupons (%wt) copper lead iron zinc arsenic 70 – 73 0.07 0.06 reminder 0.020.06 2. solution the chemical composition of water solution used throughout the experiments was actually same as the chemical composition of water used in the cooling system of al-dura refinery iraq as follows: table 3, chemical composition of tested solution component concentration, ppm na + 441 cl 303 so4 -2 352 hco3 123 co3 -2 37 the tested solution was prepared by dissolving 500 ppm nacl, 520 ppm na2so4, 170 ppm anhydrous nahco3, and 66 ppm na2co3 in one liter of distilled water. inhibitor solution was prepared by dissolving appropriate amount of polyvinyl alcohol (pva). 3. chemicals the table below lists the compounds and chemical used in this investigation: table 4, compound used in this investigation compounds formula purity% acetone c3h6o 99.5 benzene c6h6 hydrochloric acid hcl 98.9 poly vinyl alcohol c2h3or* sodium chloride nacl 95.5 sodium carbonate naco3 96 sodium bicarbonate nahco3 97.9 sodium sulfide na2so4 90 * where r : h or coch3 aprael s. yaro and munaf a. idan -available online at: www.iasj.net ijcpe vol.14 no.4 (december 2013) 21 4. weight loss method specimens were abraded in sequence under running tap water using emery papers of grade numbers; 220, 320, 400, and 600 respectively, washed with running tap water followed by distilled water, dried on a clean tissue, immersed in benzene for five seconds and dried with clean tissue, immersed in acetone for five seconds and dried with clean tissue, kept in a desiccator over silica gel for one hour before each run. procedure 1. the dimensions of each specimen were measured with vernire to the 2 nd decimal of millimeter and accurately weight to the 4 th decimal of gram before using. 2. before each test, the cell was washed with running tap water followed by distilled water and test solution. 3. specimens were completely immersed in 1000 cm 3 solution of corroding contained in the cell. they were exposed for period of 24 hours, desired concentration of inhibitor and the coupons were apart 3 and 7 cm from each other. 4. all the experiments were done with an area ratio of c/a (2.4:1 and 1:1), the working electrode was constructed joining metal coupons with above mentioned area ratio for mild steel, connected to an insulated copper wire. 5. after each test, the mild steel specimen was washed with running tap water, scrubbed with a brush to remove corrosion products, then washed with tap water followed by distilled water and dried on a clean tissue, immersed in benzene, dried, immersed in acetone, dried and left in a desiccators over silica gel for one hour before weighting then accurately weight to the 4 th decimal. results and discussion a total of 16 runs for weight loss measurements were made expressing rate of two area ratio of mild steel couple to copper in simulated cooling water system containing different concentration of pva as corrosion inhibitor. two levels for both the distance and area ratio of (ac/aa) for electrode were adopted, while four levels for inhibitor concentration as independent variables. corrosion rate calculations of mild steel (anode) coupled to copper (cathode) from weight loss data were performed using the following equation: ( ) ( ) ( ) ( ) …(1) table 5, corrosion rate of mild steel coupled to copper in simulated cooling water under different operating conditions corrosion rate (gmd) distance between fe-cu (3 cm) distance between fe-cu (7 cm) inhibitors concentrations (ppm) area ratio cu/fe(1:1) area ratio cu/fe(2.4:1) area ratio cu/fe(1:1) area ratio cu/fe(2.4:1) blank 11.77 20.95 7.698 15.47 1000 7.756(54) 11.32(46) 5.707(34.1) 9.987(35.5) 4000 3.541(70.7) 6.04(71.1) 2.254(51.5) 5.627(63.6) 7000 1.668(82.9) 4.15(80.2) 1.317(86) 3.306(78.6) ( ) indicates % inhibition in presence of pva as corrosion inhibitor. the quantitative description of the physical condition effect on corrosion rate of mild steel coupled to copper in simulated cooling water was performed. an empirical modeling technique called response surface corrosion inhibition of galvanic couple copper alloy/mild steel in cooling water system 22 ijcpe vol.14 no.4 (december 2013) -available online at: www.iasj.net methodology is used to evaluate the relationship between the controllable experimental variables and observed results. [13]. the results were analyzed using the analysis of variance (anova) as appropriate to experimental design used. the regression equations obtained gives the corrosion rate of mild steel coupled to copper as cathodic element in galvanic corrosion, as function of area ratio (x1) and distance between the electrodes (x2), in absence and presence of corrosion inhibitor (0,1000,4000and7000)ppm. regression analysis was utilized by using statistica program version 10.1 to generate four models for given inhibitor concentration with correlation coefficient of r2=1.0. crblank = 7.5 + 7.32 x10.765 x2 0.25 x1x2 …(2) cr1000 ppm = 7.13+ 2.16 x10.64 x2 + 0.13 x1x2 …(3) cr4000 ppm= 3.18 + 1.33 x1 0.48 x2 + 0.15 x1x2 …(4) cr7000 ppm= -0.11 + 2.04 x1+0.0003 x2 0.09 x1x2 …(5) where x1, x2 are the area ratio and distance between electrodes respectively and cr is the corrosion rate in (gmd). equations (2 through 5) showed suitable models to describe the response of the mild steel coupled to copper under investigation. a high values of r2 =1 justified excellent correlation between the independent variables. this indicates a good agreement between the predicted and experimental values of the corrosion rates of mild steel coupled to copper as shown in table (5). thus the effect of distance between the anodic and cathodic elements in galvanic couple and the area ratio of (c/a) on the response can be obtained at fixed levels of inhibitor concentrations (0,1000,4000and7000 ppm). the darker the red color means higher corrosion rate of mild steel coupled to copper, while the darker the green color means the lower the corrosion rate. figures (1 through 5) corroborate the fact that minimization of corrosion rate of mild steel coupled to copper as cathodic element is possible in simulated cooling water only at low c/a area ratio and large anode to cathode distance apart. the corresponding analysis of variance (anova) is represented in tables (6 through 9) in absence of inhibitor and at different inhibitor concentrations. the result obtained from this analysis indicate the significance of variables studied through the p-value (i.e., p-value is less than 0.05). fig. 1, three dimensional surface plot showing corrosion rate of carbon steel coupled to copper in scw in absence of pva as corrosion inhibitor at different area ratios and distance between anode and cathode aprael s. yaro and munaf a. idan -available online at: www.iasj.net ijcpe vol.14 no.4 (december 2013) 23 table 6, anova for corrosion of mild steel coupled to copper in simulated cooling water in absence of inhibitors, at different area ratios and distances between electrodes source of variation sum of squares degree of freedom ms effect fₒ p-value x1 72.0801 1 72.0801 147.102 0.000065 x2 22.9441 1 22.9441 46.825 0.00082 x1x2 0.5027 1 0.5027 1.0259 0.00825 error 1.96 4 0.4900 fig. 2, three dimensional surface plot showing corrosion rate of carbon steel coupled to copper in scw containing 1000 ppm pva as corrosion inhibitor at different area ratios and distance between anode and cathode table 7, anova for corrosion of mild steel coupled to copper in simulated cooling water in 1000 ppm pva, at different area ratios and distances between electrodes source of variation sum of squares degree of freedom ms effect fₒ p-value x1 15.3821 1 15.8321 114.725 0.000074 x2 2.8595 1 2.8595 20.721 0.00093 x1x2 3.3282 1 3.3282 24.1173 0.00221 error 0.552 4 0.138 fig. 3, three dimensional surface plot showing corrosion rate of carbon steel coupled to copper in scw containing 4000 ppm pva as corrosion inhibitor at different area ratios and distance between anode and cathode corrosion inhibition of galvanic couple copper alloy/mild steel in cooling water system 24 ijcpe vol.14 no.4 (december 2013) -available online at: www.iasj.net table 8, anova for corrosion of mild steel coupled to copper in simulated cooling water in 4000 ppm pva, at different area ratios and distances between electrodes source of variation sum of squares degree of freedom ms effect fₒ p-value x1 0.73017 1 0.73017 3.9035 0.000037 x2 8.64654 1 8.64654 46.2246 0.00078 x1x2 0.18076 1 0.37405 1.9997 0.00482 error 0.74822 4 0.187055 fig. 4, three dimensional surface plot showing corrosion rate of carbon steel coupled to copper in scw containing 7000 ppm pva as corrosion inhibitor at different area ratios and distance between anode and cathode table 9, anova for corrosion of mild steel coupled to copper in simulated cooling water in 7000 ppm pva, at different area ratios and distances between electrodes source of variation sum of squares degree of freedom ms effect fₒ p-value x1 4.99746 1 4.99746 82.3305 0.000013 x2 0.35701 1 0.35701 5.8757 0.00035 x1x2 0. 6076 1 0. 6076 10.0099 0.00591 error 0.2428 4 0.0607 conclusions on the basis of the results presented, the following conclusions can be drawn: 1. the inhibition action of (pva) increases with the increase of inhibitor concentration and distance between anode and cathode. 2. the methodology of three level factorial design was shown to be very useful for the process variables evaluation as main and combined effect on the response. 3. the multi-variable regression describes the behavior of the corrosion inhibition process with high accuracy (r 2 =1.0). 4. the importance of galvanic phenomenon is greater than as the ratio of cathode/anode increases, however the results show compatibility of both materials at both area ratios and (pva) concentrations except at 7000 ppm the couple not severing from galvanic corrosion. references 1c. m. mustafa and s. m. s. i. dulal, “molybdate and nitrite as corrosion iinhibitors for copper-coupled steel in simulated cooling water,” corrosion, vol. 52, no. 1, pp. 16–22, 1996. aprael s. yaro and munaf a. idan -available online at: www.iasj.net ijcpe vol.14 no.4 (december 2013) 25 2e. j. talbot and d. r. talbot, corrosion science and technology, crc press, new york, ny, usa, 2007. 3j. r. davis, “corrosion fundamentals, testing and protection,” asm international and the materials information society, ohio, ee.uu, 2000, http://www.asm.intl.org/. 4r. francis, “galvanic corrosion of high alloy stainless steels in sea water,” british corrosion journal, vol. 29, no. 1, pp. 53–57, 1994. 5p. r. roberge, corrosion engineering: principles and practice, mcgraw–hill, new york, ny, usa, 2008. 6i. carrillo, inhibition of the corrosion in galvanic couples coppe and carbon steel of heat exchangers for heavy machinery industry, m.s. thesis, instituto de ingenieria de la universidad autonoma de baja california for engineering master degree, 2009. 7k. e. johnson and j. s. abbott, “bimetallic corrosion effects on mild steel in ‘natural environments: british steel corporation report no. cel/cc/5/75, february 1975. 8v. kucera and e. mattsso~ “atmospheric corrosion of bimetallic structures,” atmospheric corrosio~ hollywood florid% 5-10 october 1980, john wdey and sons, inc., pp. 561-574, 1982. 9r. j. schmitt and e. h. phelps, “constructional steels in marine applications,” journal of metals, pp. 47-55, march 1970. 10uhlig h.h., “corrosion handbook”, john wiley and sons, inc., 2011. 11corrosion inspection and monitoring by pierre r.roberge .royal. military college of canada in (2007). 12corrosion science and technology by david talbot james talbot (1998). 13perry d.h “experimental design in biotechnology”, marcel dekker,inc. usa (1989). available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.22 no.2 (june 2021) 7 – 16 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: abimbola george olaremu , email: abimbolaremu@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. effect of temperature on gas and liquid products distribution in thermal cracking of nigerian bitumen abimbola george olaremu a , ezekiel oluyemi odebunmi b and jim a anderson c a department of chemical sciences, adekunle ajasin university, akungba akoko, nigeria b department of chemistry, university of ilorin, nigeria c surface chemistry and catalysis group, school of engineering, university of aberdeen, uk abstract the increasing population growth resulting in the tremendous increase in consumption of fuels, energy, and petrochemical products and coupled with the depletion in conventional crude oil reserves and production make it imperative for nigeria to explore her bitumen reserves so as to meet her energy and petrochemicals needs. samples of agbabu bitumen were subjected to thermal cracking in a tubular steel reactor operated at 10 bar pressure to investigate the effect of temperature on the cracking reaction. the gas produced was analyzed in a gas chromatograph while the liquid products were subjected to gas chromatography-mass spectrometry (gc-ms) analysis. heptane was the dominant gas produced in bitumen cracking at all temperatures and the reaction products show a distribution of lighter hydrocarbons most of which are in the gasoline range. the product distribution of bitumen conversion depends strongly on the cracking temperature and the oil produced contains the valuable liquid fractions. the products of thermal cracking of bitumen can be classified into the following groups; alkanes, alkenes, amines, aromatics, alkanoic acids, alkanols, esters, ethers, ketones, sulphur compounds, and nitrogen compounds. the activation energies of the products formed were determined. the lng produced all have unusually low values activation energy (hence easily converted) pointing to the high quality of agbabu crude the conversion process was affected by the reaction time and suggests that the transformation of bitumen into smaller fractions follows a definite reaction scheme in which the heavy oil transformed to lower fractions and was subsequently converted to smaller liquid fractions and gases. keywords: agbabu bitumen, petrochemicals, cracking, activation energy received on 04/04/2021, accepted on 19/06/2021, published on 30/06/2021 https://doi.org/10.31699/ijcpe.2021.2.2 1introduction the worldwide production of conventional crude oil is expected to reach its crest in the second decade and subsequently enter a phase of everlasting decline [1]. to meet the increasing need for light oil, interest has switched to unusual sources of which natural bitumen and heavy crude oil are the most readily accessible to meet-up with both the shortand long-term demand [2]. bituminous sands are made up of mineral matters, heavy oil, water, and are rich in minerals. the heavy oil in bituminous sands is regarded as bitumen while the sandy and clayey mineral contents are referred to as mineral matter [3]. bitumen is viscous with high density (1.0 g/cm 3 ) or low api gravities (< 22 o api). it has chemical properties comparable to conventional crude oils [4,5]. the nigerian bitumen reserve has been conventionally projected to be more than 50 million tons. based on average bitumen content of 15% by weight the nigerian rich bitumen deposits constitute a possible reserve of over 40 billion barrels of bitumen [6], which is about 40 % of canada’s deposit known to be one of the world’s richest deposits of bitumen [7]. at low temperature and pressure (673 k, 620 kpa) bitumen is broken down to gasoline high in aromatic hydrocarbon, coke, and gases [8, 9]. it has been reported that the decomposition of the utah bitumen to gases and oils occurred within 400 and 420 o c, and a further increases in the reaction temperature had little or no effect on product yield. [10]. hayashitani, [11, 12] studied the decomposition of athabasca bitumen using the thermal process at different reaction times at 360, 397, and 422 o c. the products' yield i.e coke, asphaltenes, heavy oils, gases, light oils, and middle oils as a function of time and temperature were employed in the determination of kinetic data for predicting the amount of combustion fuel obtainable in an in-situ operation and their composition. another study of the thermal decomposition of asphaltenes [13] showed that there was no induction stage for the formation of coke and that the molecular weight of asphaltenes did not change throughout the process. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:abimbolaremu@yahoo.com http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2021.2.2 a. g. olaremu et al. / iraqi journal of chemical and petroleum engineering 22,2 (2021) 7 16 8 speight investigated the mechanism of the thermal decomposition of asphaltenes sourced from athabasca bitumen and deasphaltenated oil using the distillation method (destructive) [14]. an evaluation of the data obtained indicated that significant changes took place during cracking. in other studies [15, 16, 17], the thermal reactions of athabasca bitumen and deasphated athabasca bitumen were investigated at high temperatures using a micro-autoclave. the analysis of reaction products showed that about 46 wt% of pentane soluble (maltenes) was formed and that the composition of the maltenes is; 3.5 wt % polar compounds, 5 wt% mono and diaromatics, 17 wt % saturates, and 20.5 polyaromatics. they also found that partial deasphalting of bitumen leads to the production of products with better quality such as reduced metals content, viscosity, and micro carbon residue. in another work, yasar and co, [18] studied the pyrolysis of maltenes, isolated asphaltenes, and resids from arabian light, arabian heavy, hondo, and maya oils. at 673 and 698 k, isolated asphaltenes reacted selectively to form maltenes. at higher temperatures (723k), asphaltenes reacted predominantly to form coke. detailed product analyses from the thermal cracking of athabasca bitumen vacuum bottom and sara fractions revealed that saturates and monoand diaromatics were relatively unreactive, whereas polyaromatics and resins were converted to smaller molecules including saturates. the product obtained included aromatic fractions and a small amount of coke. the results of the study by dawson et al. showed that side chain and dehydrogenation /hydrogenation reactions are major routes in the thermal cracking of heavy oils and bitumen [19]. liu et al.,[20] in correlation studies of the pyrolysis of feedstock obtained by supercritical extraction from some chinese light crude oils and oils from saudi arabia and oman compared the behavior of oil to their properties. eshraghian and husein in another study investigated athabasca vacuum residue and bitumen in a closed autoclave reactor system at 400-420 °c and produce gas yield below 10 wt% [21], a similar result was obtained by yunanto et al, 2019[22]. the evolution of mass losses and production of gases from oils during low –temperature oxidation (lto) was also reported and the products analyzed by ftir and sara [23-25] according to atkins [26], the large reservoir of bitumen and heavy crude oil deposits in angola, nigeria, egypt, and other african countries are yet to be exploited because of the limited or no studies on the upgrading technology. for example, the southwest nigerian bitumen reserve has been predictably estimated to be over 50 million tons. on average bitumen content of 15%, wt the regional rich tar sand deposits constitute a latent reserve of over 40 billion barrels of bitumen [6] approximately 40 % of canada’s deposits regarded as the richest deposits of tar sands globally [7]. thus, this work aims to carry out thermal cracking of nigerian bitumen, analyze the gaseous and liquid products to obtain relevant kinetic data and information on product distribution. 2experimentals 2.1. description of reactor a tubular batch steel reactor designed and constructed in-house was used for the cracking of bitumen. all pressure fittings were made of stainless steel 316 grade and purchased from swagelok uk. the reactor is 1cm diameter and 15cm length connected to a ¼ in the tube. the control line of the reactor was fitted with a pressure relief valve for safe operation, gas inlet and outlet manual valves, and a pressure gauge to monitor the system pressure. a type k thermocouple (rs components) was inserted from the top of the pressure line to measure the temperature in the centre of the reactor tube. the furnace can operate at a maximum operating temperature of 550 °c, which was measured with an external type k thermocouple placed at its centre, connected to a temperature controller. the furnace and reactor were located inside a fume cupboard for safety during operation. a schematic diagram of the apparatus including the reactor used for the cracking of the bitumen is presented in fig. 1. fig. 1. diagram of reactor used for cracking of bitumen 2.2. thermal cracking of agbabu bitumen the cracking process was carried out in the laboratory using the constructed steel reactor (figure 1). 10 g sample of bitumen was introduced into the reactor for each run. the reactor tube was then connected to the ¼ in. pressure line through a straight union and a pressure nitrogen (n2) cylinder was connected to the control line. the reactor was purged with nitrogen gas to remove air before the system was pressurized and checked for leakages. if any leakage was observed, the system was depressurized and the leaks fixed. subsequently, the reactor was pressurized to 10 bar with nitrogen gas. the cracking of bitumen was carried out at 400, 450, and 500 o c. the cracking reaction was initiated after the operating conditions have been attained. the products of cracking which included gases and light oil were collected. the gases were then flashed off, and either vented or sent to the refinery gas analyzer (rga) for concentration and compositional analysis. a. g. olaremu et al. / iraqi journal of chemical and petroleum engineering 22,2 (2021) 7 16 9 2.3. refinery gas analyser (rga) the compositional analysis of the gases was done using perkin elber auto system xl chromatographer fitted with flame ionization detector(fid). the gas chromatograph(gc) was equipped with porapak q as support, having mesh range 80/100, length of 6 ft o.d1/8” i.d 0.085”. the hydrocarbon components in the gaseous stream were determined by the fid channel column capable of separating hydrocarbons based on the calibrated table. the operating conditions of the fid channel were: hydrogen (45 ml.min -1 ), air (400 ml.min 1 ), reference (45 ml.min -1 ), and makeup flow n2 (25 ml.min -1 ); the oven temperature program was 40 °c for 2 min, and then a temperature program of 7.5 o c/min to 100 o c for 5min, 12.5 o c/min to 180 o c for 10 min and 15.0 °c/min up to 225 °c (20 minutes). 2.4. gc-ms analysis of the oil produced from bitumen cracking quantitative and qualitative data were obtained by gcms analysis of the raw bitumen and oil produced from all cracking processes. each sample was dissolved in 10 % tetrahydrofuran (thf) and then injected into an agilent tech 7820 a gas chromatograph hyphenated with an agilent 5977e mass selective detector (msd) operating in electron impact mode. products were analyzed in selected ion monitoring (sim) mode. an hp-5 30 m x 0.25 mm x 0.25 μm capillary column was used for the gc with helium as carrier gas at a constant flow rate of 1.0 ml/min. the oven temperature program was 40 °c for 5 min, and then a temperature program of 40 o c/min to 140 o c for 3min, and 8 °c/min up to 280 °c where it was held to 20 minutes. the samples were run using full scan, single ion monitoring (sim), and recorded using the hp chemstation data system [27] .the identification of the components was based on the comparison of retention times of the components and spectral with those data in the library. 3results and discussion 3.1. gaseous products of thermal cracking of bitumen the cracking of bitumen was carried out in the temperature range 400 to 500 o c at 10 bar reactor pressure and five hours' time-on-stream. the changes in gas composition as a function of time at different temperatures are presented in figures 2-4. the analysis of gas composition by refinery gas analysis showed that heptane, octane, decane, and dodecane are the major products obtained from the thermal cracking of bitumen at 400 o c, 450 o c, and 500 o c. other components include; methane, ethane, propane, butane, isobutane, pentane, methyl pentane, hexane, and nonane. the production of gases increased as the reaction temperature attained 400 o c with heptane and octane dominating. at an experimental run-time of 120 minutes, product generation drastically fell especially the higher components (heptane and octane) in the gas mixture. the amount of the different gases generated was not stable until about 240 min into the process and remained at a plateau. at 450 o c, due to the increase in temperature, the production of intermediate compounds was observed. heptane, dodecane, decane, hexane, pentane, and butane were produced more within the first one hour of reaction. the amount of the different gases generated was not stable until about 180 to 240 minutes into the experiment and maintained the gas generation till the end of the experiment as was observed during the thermal cracking at 400 o c. the generation of all the gaseous products reached their climax after 60 minutes of cracking time producing more hydrocarbons with higher concentration at 500 o c. the amount of the different gases generated was not stable until about 180 to 240 minutes into the experiment and maintained the gas generation till the end of the experiment as was observed during the cracking at 400 o c. the profiles in figures 2-4 give the details of the gases obtained as a function of reaction time. results showed that an increase in the reaction temperature enhanced the formation of gases. the formation of gas occurred at a higher rate within the first hours of reaction time and then declined. this phenomenon could be associated with the breaking down of the paraffinic chains present in asphaltenes and other large molecules present in the bitumen in the early stage of the reaction, and with the cracking of smaller ones in the latter stages of the reaction. the obtained result was similar to the one reported by martinz-grimaldo and co-workers [28]. thermal cracking generally takes place via a free radical mechanism which involves a series of reaction steps, including chain initiation, hydrogen abstraction reaction, radical decomposition reaction, radical addition reaction, and termination reaction [29, 30, 31]. from the results shown in figures 2-4, the gas formation was found to increase with an increase in the processing temperature. these observations are similar to what was reported for the coking of arabian mix vacuum residue [32].the reaction products of bitumen cracking show the distribution of lighter hydrocarbons most of which are in the gasoline range. it was observed that c5 to c12 components were present in the chromatogram with a peak of c7 for thermal cracking at 400 o c and 500 o c while a peak of c12, closely followed by c7 was obtained at 450 o c. the c1-c4 are used as fuel(burned), ethane can be pyrolyzed to produce ethylene, propane or a mixture of propane and butane can be utilized as liquefied petroleum gas (lpg), the c6-c15 fractions are used as jet fuel and kerosene, while c5-c8 which are hydrocarbons primarily suitable for gasoline and c4 may be added to achieve additional volatility [30]. a. g. olaremu et al. / iraqi journal of chemical and petroleum engineering 22,2 (2021) 7 16 10 as the reaction temperature increases, thermal cracking becomes significant prompting the breakingdown of heavy molecules into smaller ones. this was confirmed by the results of the investigation reported in the open literature, during hydrotreating/cracking of heavy oil in fixed and fluidized bed reactors under similar reaction conditions [33-35]. fig. 2. product distribution of thermal cracking at 400 o c fig. 3. the product distribution of thermal cracking at 450 o c fig. 4. the product distribution of thermal cracking at 500 o c fig. 5. barchart for product distribution of thermal cracking of bitumen at 450 o c after minutes 3.2. liquid products gc-ms spectra of the liquid products (oil) obtained during thermal cracking of nigerian bitumen at temperatures of 400,450 and 500 o c are presented in fig. 6 to fig. 8 and table 1 contains a summary of the classes of compounds identified at the various temperatures. as the results show, the product distribution of bitumen conversion strongly depends on the cracking temperature. numerous products were formed during the thermal cracking of the bitumen and they can be classified into the following groups; alkanes, alkenes, amines, aromatics, alkanoic acids, alkanols, esters, ethers, ketones, sulphur compounds, and nitrogen compounds. at all the cracking temperatures, alkanes, aromatics, and amines are the major products obtained from the cracking of bitumen. according to beaton and bertolacini [36], as the temperature was increased to 450 o c, the production of other chemicals such as alkenes, alkanoic acids, alkanols, and esters were enhanced at different rates. but at 500 o c, the conversion to alkanes was enhanced by the high heating temperature. at low temperatures, the molecules are not provided with sufficient energy to break down the bonds and consequently few radicals are produced resulting in reactions proceeding slowly. this then resulted in the production of lower amounts of products at low temperatures compared to high-temperature operations. free radicals are generated from the feed in the initiation step and these radicals can undergo further reactions and produce new and/or more stable radicals (propagation step). in the fragmentation step, however, a free radical forms an unsaturated molecule and a new radical. the alkene double bond is weak and its production is not well-favored due to its weak bonds. as such, the driving force for the fragmentation reactions was associated with the presence of a highly weak radical, which led to alkene [37]. 50 100 150 200 250 300 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 c o n c e n tr a ti o n ( p p m ) time-on-stream (minute) methane ethane propane butane ibutane pentane methylpentane hexane heptane octane nonane dodecane 50 100 150 200 250 300 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 c o n c e n tr a ti o n ( p p m ) time-on-stream (minute) methane ethane propane butane ibutane pentane methylpentane hexane heptane octane nonane decane dodecane 50 100 150 200 250 300 -0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 c o n c e n tr a ti o n ( p p m ) time-on-stream (minute) methane ethane propane butane ibutane pentane metylpentane hexane heptane octane nonane decane dodecane time (minute) 0 1000000 2000000 3000000 4000000 5000000 6000000 7000000 8000000 9000000 a re a methane ethane propane butane ibutane pentane mpentane hexane heptane octane nonane decane dodecane a. g. olaremu et al. / iraqi journal of chemical and petroleum engineering 22,2 (2021) 7 16 11 the results presented in fig. 9 showed that the production of aromatics was high at lower temperatures. this is because at relatively low temperatures, the aromatic rings are very hard to break down owing to their high bond dissociation energy. at the lower temperatures, the major conversions happened in the aliphatic bonds [37]. however, at 500 o c, the amount of aromatics was reduced from 37.71% to 32.83% as expected. thermal cracking of bitumen, even at low temperatures, resulted in desulphurization. according to fig. 10, the naphthalene present in the products obtained during the thermal cracking of bitumen increased with increase in temperature. fig. 6. gc-ms spectrum of products of thermal cracking of bitumen at 400 o c fig. 7. gc-ms spectrum of products of thermal cracking of bitumen at 450 o c fig. 8. gc-ms spectrum of products of thermal cracking of bitumen at 500 o c a. g. olaremu et al. / iraqi journal of chemical and petroleum engineering 22,2 (2021) 7 16 12 table 1. summary of the class of compounds identified by gc-ms class of compound amount produced ( %) 400 o c 450 o c 500 o c alkanes 22.1 16.71 39.34 alkenes 2.88 amines 27.12 27.63 20.05 aromatics 37.71 37.58 32.83 alkanoic acid 0.26 5.97 4.61 alkanols 1.6 1.18 1.4 esters 5.63 1.66 1.07 ethers 0.23 ketones 0.7 sulphur compounds 5.27 5.48 nitrogen compound 0.3 others 0.01 0.61 0.00 fig. 9. composition of liquid products during thermal cracking of bitumen at temperatures of 400, 450, and 500 o c fig. 10. naphthalenes in products of thermal cracking at 400, 450, and 500 o c gaseous products distribution: effect of temperature. methane yield as a function of temperature during thermal cracking of bitumen is presented in figure 11. at the lower temperature of 400 o c, moderate levels of bitumen cracking were observed with methane having a concentration of 0.01089 ppm after 60 minutes of cracking. bitumen cracking improved with increasing temperature as methane had a concentration of 0.02292 ppm and 0.04328 ppm at 450 and 500 o c respectively after 60 minutes-time-on stream. this shows that the cracking of molecules became important as the reaction temperature was increased, leading to the breaking down of heavy molecules into smaller ones. this is agreed with literature reports [33-35]. the same trend was maintained for all the other gaseous hydrocarbon products generated during the thermal cracking of bitumen. fig. 11. methane produced at 400 o c, 450 o c, and 500 o c during thermal cracking of bitumen 3.3. kinetic analysis of bitumen thermal cracking data many complex reactions occur during the bitumen decomposition process, and it is almost impossible to estimate the intrinsic kinetics of all reactions [38]. however, reactions of primary interest are those that crack macromolecular bitumen into volatile compounds that can be measured using the gas chromatograph with the injection port temperature of 400 0 c. the cracking reactions of bitumen and its fractions have been reported by previous researchers to be first order with respect to hydrocarbons [39] and zero with respect to hydrogen [40]. the first step in this kinetic assessment considers the translation of the bitumen into lighter products as an irreversible first-ordered reaction, represented by: bitumen fraction → lighter products the first-order rate constant, k, for the decrease in the bitumen concentration from its initial value, x0, to its value xt at time t was obtained from the equation [41]: k =l/t ln[xo/(xo xt)] (1) 380 400 420 440 460 480 500 520 0 5 10 15 20 25 30 35 40 p er ce n ta g e co m p o si ti o n temperature alkanes alkenes amines aromatics alkanoicacid alkanol ester ether ketone sulphurcompounds nitrogencompounds naphthalene 0 1 2 3 4 p e rc e n ta g e cracking temperatures 400 450 500 50 100 150 200 250 300 0.00 0.02 0.04 0.06 0.08 0.10 0.12 c o n c e n tr a ti o n ( p p m ) time-on-stream (minute) 400 450 500 a. g. olaremu et al. / iraqi journal of chemical and petroleum engineering 22,2 (2021) 7 16 13 the integrated form of the first-order rate equation was then used to analyze the data to determine first order rate constants for all the hydrocarbons produced during bitumen cracking. the linear first-order plots are presented in figures 12-14 for bitumen cracking at 400 o c, 450 o c, and 500 o c. the arrhenius equation was used to determine the activation energy for the products. the results are presented in table 2 table 2. rate constant sand activation energy for different hydrocarbon molecules k1, s -1 k2, s -1 k3s -1 ea(kjmol -1 ) methane 0.00223 0.003358 0.00593 16.0963 ethane 0.002235 0.004538 0.004258 11.1493 propane 0.001855 0.005324 0.001891 1.6096 butane 0.002004 0.005892 0.001612 2.1367 ibutane 0.002021 0.005701 0.002113 1.9921 pentane 0.007284 0.008173 0.006256 2.2831 methylpentane 0.002134 0.004811 0.001978 0.2049 hexane 0.006627 0.01834 0.00322 10.2431 heptane 0.006448 0.01029 0.009625 6.9640 octane 0.02013 0.005495 0.04093 9.7120 nonane 0.0004638 0.002157 0.00546 41.2050 decane 0.02054 0.0229 0.003454 28.2850 dodecane 0.01268 0.0199 16.8778 the linear form of the plots in figures 12-14 suggests that a first-order mechanism described the transformation of the nigerian bitumen thermally. a systematic change in rate constant was noticed as the reaction temperature was increased as expected. there was a slight decrease in the rate constants of lower hydrocarbons as the temperature was increased to 500 0 c because the cracking severity of bitumen increased leading to the production of more products which may increase the presence of light hydrocarbons. 0 1 0 0 2 0 0 3 0 0 4 0 0 1 5 1 0 5 0 t h e r m a l 4 0 0 t im e ( m in ) in b f m e t h a n e e t h a n e p r o p a n e b u t a n e ib u t a n e p e n t a n e m e -p e n t a n e h e x a n e h e p t a n e o c t a n e n o n a n e d o d e c a n e fig. 12. nigerian bitumen: thermal cracking at 400 0 c 0 1 0 0 2 0 0 3 0 0 4 0 0 1 0 8 6 4 2 0 t h e r m a l 4 5 0 t im e ( m in ) in b f m e t h a n e e t h a n e p r o p a n e b u t a n e ib u t a n e p e n t a n e m e -p e n t a n e h e x a n e h e p t a n e o c t a n e d e c a n e n o n a n e d o d e c a n e fig. 13. nigerian bitumen: thermal cracking at 450 0 c 1 0 0 2 0 0 3 0 0 4 0 0 1 5 1 0 5 0 5 t h e r m a l 5 0 0 t im e ( m in ) i n b f m e t h a n e e t h a n e p r o p a n e b u t a n e ib u t a n e p e n t a n e m e -p e n t a n e h e x a n e h e p t a n e o c t a n e d e c a n e n o n a n e d o d e c a n e fig. 14. nigerian bitumen: thermal cracking at 500 0 c according to the literature [42], the activation energy of the thermal cracking reactions lies between 174 and 268 kjmol -1 . the energies required to activate the decomposition of some light hydrocarbons majorly are between 24.3 (neo-c5h12) and 56.9 kj mol -1 (ch4). the value 102.5 kj mol -1 was the highest discovered for ch3cho. barbour et al.[37] reported that a first-order rate constant, k, was observed during the pyrolysis of bitumen with sand, and corresponding activation energy of138 kj mol -1 was observed. however, alsoufi et al. [43] during the cracking of atmospheric residue obtained a relatively low value of activation energy (99 kj/mol). from the obtained results, values of activation energies in this study are also in the range from 102 to 206 kjmol 1 [44]. most studies made use of solvent extractions in separating the different phases in the pyrolyzed-product. [42], however, the methods of separating products do not affect activation energies reported which are due to differences in the chemistry of pyrolysis, or the analytical procedures employed [45]. a. g. olaremu et al. / iraqi journal of chemical and petroleum engineering 22,2 (2021) 7 16 14 vyazovkin has described the interpretation of activation energy as a concession in a way as to analyze the reasons for variation in activation energies in terms of mechanistic steps. [46]. as predicted by nassar et. al.[47], we can obtain a variation in activation energy with conversion processes. strauszet and co-worker reported unusually low values of the activation energies measured for products formation during the pyrolysis of athabasca oil sand with values of 56.9kj mol -1 , 34.7kj mol -1 , 57.7kj mol -1 , 48.5kj mol -1 , 28.4kj mol -1 and 48.kj mol -1 for methane, ethane, propane, butane, ibutane and pentane respectively [48]. they ascribed the low activation energy to a catalytic effect of the mineral matter present in the crude. however, in this work, according to table 2, the activation energies for the production of different products were relatively lower than what was reported for athabasca bitumen. methyl pentane had the lowest activation energy of 0.204kjmol -1 , followed by propane, ibutane, butane, and pentane. the c1-c4 are used as fuel(burned), ethane can be pyrolized to produce ethylene, propane or a mixture of propane and butane can be utilized as liquefied petroleum gas (lpg), c6-c15 is used as jet fuel and kerosene, while c5-c8 which are hydrocarbons primarily suitable for gasoline and c4 may be added to achieve additional volatility. 4conclusion from this study, the following conclusions can be drawn: 1the transformation of agbabu bitumen into smaller fractions follows a definite reaction scheme in which higher molecular weight hydrocarbon’s converts to smaller ones and these fractions are subsequently converted to liquid fractions and gases. 2the gaseous hydrocarbons were produced from the higher fractions 3temperature and reaction time has a higher effect on the scheme 4products are lighter hydrocarbon’s mostly in the gasoline range c5 to c12 fractions were obtained with a peak at c7 for thermal cracking at 400 and 500 o c while a peak of c12 closely followed by c7 was obtained at 450 o c. 5the liquid phase contains the most valuable products; hence, it is the most important product from the process. the results showed that the temperature of the reactor affects the percentage fraction of each component with reaction time. numerous products were formed during the thermal cracking of the bitumen. these products can be classified into the following groups; alkanes, alkenes, amines, aromatics, alkanoic acids, alkanols, esters, ethers, ketones, sulphur compounds and nitrogen compounds. 6the decomposition of agbabu bitumen perfectly fit into first-order kinetics model and low energy of activation is required for the conversion of bitumen into valuable products references [1] stosur, g. j., waisley s. l., reid t. b., and marchant l. c. (1998) “tar sands – technology, economics and environmental issues for commercial production beyond the 2000”, paper no 1998-002 presented at the 7th. unitar international conference on heavy oil and tar sand, beijing, china, 27-30th october, 11-18. [2] chen, z. j. (2006) heavy oils part i. siam news, 39, 3. [3] adegoke, o.s., ako, b.s., enu, e.i., afonja, a.a., ajayi, t.r., enufurieta, w.o., jeje, l.k., dogoke – anthony, c.w., omatshola, m.e and rahaman, m.a (1989).“the tar sands of ondo state’’ a brochure was prepared for the state visit by the president and commander-in-chief of armed forces of the fed.rep. of nigeria. pp 6-26. [4] coker, s.j.l. (1988) “bitumen saturation and reserve: estimate of okitipupa oil sand”.nigeria journal of mining geology. 38: 1-2. [5] obiajunwa, e.i.,and nwachukwu,j.i.(2000). “simultaneous pixe and pigme analysis of a nigerian tar sand sample from a deep borehole”.j.radio anal.nucl.chem.245:659-661. [6] adegoke, o.s., and ibe, e.c. (1982): "the tar sand and heavy crude resources of nigeria", proceedings of 2 nd international conference on heavy crudes and tar sand.caracas, venezuela. pp. 280285. [7] bello, o.o., sonibare, j.a., ademodi, b.t., macaulay, s.r.a. and adebiyi, f.m. (2003) “environmental impact assessment of commercial tar sands development in nigeria”,nafta croatia, 54 (11), pp.417-423 [8] egloff. c. and morrell, j. c. (1926) “systematic refining of cracked distillates” trans. am. inst. chem. eng., 18, 347. [9] egloff, c. and morrell. j. c.(1927) “cracking of bitumen derived from alberta tar sands .” can. chem. metall. 11,33. [10] burger, j. w., cogswell, d. e. and oblad, a. g. (1977) “thermal processing of a utah tar sand bitumen”, the oil sands of canada-venezuela symposium, cim publication.17. 178 182. [11] hayashitani. m.. bennion, d. w.. donnelly, j. k. and moore, r. g. (1977). proc. oil sands of canada-venezuela symp. cim special publication. 17. 233 [12] hayashitani, m. (1978) ‘thermal cracking of athabasca bitumen’, phd thesis, university of calgary,calgary, canada. [13] magaril, r. z. and axenova e. i., (1970) oil gas j.5. 47. [14] speight, j.g. (1970) “thermal cracking of athabasca bitumen, athabasca asphaltenes, and athabasca deasphalted heavy oil”, fuel, 49, 134-145. http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.457.92&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.457.92&rep=rep1&type=pdf https://akjournals.com/view/journals/10967/245/3/article-p659.xml https://akjournals.com/view/journals/10967/245/3/article-p659.xml https://akjournals.com/view/journals/10967/245/3/article-p659.xml https://akjournals.com/view/journals/10967/245/3/article-p659.xml https://pascal-francis.inist.fr/vibad/index.php?action=getrecorddetail&idt=15336139 https://pascal-francis.inist.fr/vibad/index.php?action=getrecorddetail&idt=15336139 https://pascal-francis.inist.fr/vibad/index.php?action=getrecorddetail&idt=15336139 https://pascal-francis.inist.fr/vibad/index.php?action=getrecorddetail&idt=15336139 https://pascal-francis.inist.fr/vibad/index.php?action=getrecorddetail&idt=15336139 https://pubs.acs.org/doi/pdf/10.1021/ie50199a021 https://pubs.acs.org/doi/pdf/10.1021/ie50199a021 https://pubs.acs.org/doi/pdf/10.1021/ie50199a021 https://prism.ucalgary.ca/handle/1880/13806 https://prism.ucalgary.ca/handle/1880/13806 https://prism.ucalgary.ca/handle/1880/13806 https://www.sciencedirect.com/science/article/abs/pii/0016236170900347 https://www.sciencedirect.com/science/article/abs/pii/0016236170900347 https://www.sciencedirect.com/science/article/abs/pii/0016236170900347 a. g. olaremu et al. / iraqi journal of chemical and petroleum engineering 22,2 (2021) 7 16 15 [15] rahimi, p., dettman, h., gentzis, t., chung, k. and nowlan,v.(1997a).“upgrading chemistry of athabasca bitumen fractions derived by super critical fluid extraction”, presented at the 47 th csche conference, edmonton, alberta, canada, october 5-8. [16] rahimi, p., dettman, h., nowlan, v. and delbianco, a.(1997b). “molecular transformation during heavy oil upgrading”, prep. div. pet. chem., american chemical society, national meeting, san francisco, ca, april 13-17; 23-26. [17] rahimi, p.m., parker, r.j., hawkins, r., gentzis, t. and tsaprailis, h.(2001) “processability of partially deasphated athabasca bitumen”, prep. div. pet. chem., american chemical society, national meeting, san diego, ca., april 1-5, 74-77. [18] yasar, m., trauth, d.m. and klein, m.t.(1992). “asphaltene and resid pyrolysis 2: the effect of reaction environment on pathways and selectivities”, prep. div. fuel chem., american chemical society, national meeting, washington, d.c., august 23-2;pp. 1878-1885. [19] dawson, w.h., chornet, e., tiwari, p. and heitz, m. (1989). hydrocracking of individual components isolated from athabasca bitumen vacuum resid, prep. div. of pet.chem.,american chemical society, national meeting, dallas, tx, april 9-14; 34(2), 384394. [20] liu, c., zhu, c., jin, l., shen, r.and liang, w. (1999).step by step modeling for thermal reactivities and chemical compositions of vacuum residues and their sfef asphalts, fuel process. technol.,59, 51-67. [21] eshraghian a and husein m.m., (2017) “thermal cracking of athabasca vacuum residue and bitumen and their maltene fraction in a closed reactor system,” fuel, vol. 190, pp. 396-408. [22] isnandar yunanto, sri haryati and muhammad djoni bustan (2019) “pyrolysis of vacuum residue by thermal and catalytic cracking using active alumina catalyst” indones. j. fundam. appl. chem., 4(1), 2019, 29-34. doi: 10.24845/ijfac.v4.i1.29 [23] jin huo, shuai zhao, jingjun pan, wanfen pu, mikhail a.varfolomeev, dmitrii a. emelianov.(2021) “evolution of mass losses and evolved gases of crude oil and its sara components during low-temperature oxidation by isothermal tg–ftir analyses”. journal of thermal analysis and calorimetry, 667 https://doi.org/10.1007/s10973-021-10841-z [24] chengdong yuan, dmitrii a. emelianov, mikhail a. varfolomeev. (2018) “oxidation behavior and kinetics of light, medium, and heavy crude oils characterized by thermogravimetry coupled with fourier transform infrared spectroscopy”. energy & fuels, 32 (4) , 5571-5580. https://doi.org/10.1021/acs.energyfuels.8b00428 [25] shuai zhao, wanfen pu, mikhail a. varfolomeev, chengdong yuan, alexander a. rodionov. (2019) “integrative investigation of lowtemperature oxidation characteristics and mechanisms of heavy crude oil”. industrial & engineering chemistry research, 58 (31) , 1459514602. https://doi.org/10.1021/acs.iecr.9b03346 [26] atkins, l., (2011). heavy crude oil: a global analysis and outlook, available at www.heavyoilinfo.com/feature-items/heavy-crude-oila-global-analysis-and-outlook, accessed 23/08/2015. [27] islas-flores, c.a.,buenrostro-gonzalez,e. and lira-galeana,e.(2005).“comparison between open column chromatography and hplc sara fractionations in petroleum”.energy and fuels 19(5), 2080-2088. [28] martinez-grimaldo, h., ortiz-moreno, hugo., sanchez-minero, f., ramirez, jorge., cuevas-garcia, rogelio., and ancheyta-juarez, jorge.(2014) “hydrocracking of maya crude oil in a slurryphase reactor.1.effect of reaction temperature”. catalysis today. 220-222, 295300. [29] gates, c. b., james, r. katzer and g.c.a. schuit (1979) “chemistry of catalytic processes mc”. graw-hill series in chemical engineering. [30] satterfield, c.n (1980). “heterogeneous catalysis in practice”. mcgraw hill, pp. 238-242. [31] speight, j. g., (2011). “the refinery of the future”. gulf professional publishing london,pp 81 116 [32] sawarkar, a.n., pandit, a.b., and joshi, j.b.(2007)“studies in coking of arabian mix vacuum residue”. chemical engineering research and design,85(a4):481-491. [33] kim, j. –w., longstaff, c. d., hanson, v. f., (1998). “catalytic and thermal effects during hydrotreating of bitumen-derived heavy oil”, fuel, 77 (15), 1815. [34] kressmann, s., more, f., harle, v., kasztelan, s., (1998). “recent development in fixed-bed catalytic residue upgrading”, catalysis today, 43, 203-215. [35] lee, h. j., kang, s., kim, y. and park, s. (2011). “new approach for kinetic modeling of catalytic cracking of paraffinic naphtha”. industrial & engineering chemistry research, 50, 4264-4279. [36] beaton, w.i. and bertolacini, r.j., (1991) “resid hydroprocessing at amoco”, catalysis reviews science and engineering, 33 (3-4), 281-317. [37] parsons, a. f (2000) “an introduction to free radical chemistry’ blackwell science;york. [38] galarraga, carmen e. , carlos scott, herbert loria, and pedro pereira-almao.(2012) “kinetic models for upgrading athabasca bitumen using unsupported niwmo catalysts at low severity conditions”. ind. eng. chem. res. 51, 140–146 dx.doi.org/10.1021/ie201202b. [39] sanchez, s.; rodriguez, m. a.; ancheyta, j.(2005) “kinetic model for moderate hydrocracking of heavy oils”. ind. eng. chem. res. 44, 9409. https://pascal-francis.inist.fr/vibad/index.php?action=getrecorddetail&idt=2634353 https://pascal-francis.inist.fr/vibad/index.php?action=getrecorddetail&idt=2634353 https://pascal-francis.inist.fr/vibad/index.php?action=getrecorddetail&idt=2634353 https://pascal-francis.inist.fr/vibad/index.php?action=getrecorddetail&idt=2634353 https://pascal-francis.inist.fr/vibad/index.php?action=getrecorddetail&idt=2634353 https://pascal-francis.inist.fr/vibad/index.php?action=getrecorddetail&idt=954707 https://pascal-francis.inist.fr/vibad/index.php?action=getrecorddetail&idt=954707 https://pascal-francis.inist.fr/vibad/index.php?action=getrecorddetail&idt=954707 https://pascal-francis.inist.fr/vibad/index.php?action=getrecorddetail&idt=954707 https://pascal-francis.inist.fr/vibad/index.php?action=getrecorddetail&idt=954707 https://pubs.acs.org/doi/abs/10.1021/ef0000577 https://pubs.acs.org/doi/abs/10.1021/ef0000577 https://pubs.acs.org/doi/abs/10.1021/ef0000577 https://pubs.acs.org/doi/abs/10.1021/ef0000577 https://pubs.acs.org/doi/abs/10.1021/ef0000577 https://pubs.acs.org/doi/abs/10.1021/ef0000577 https://www.sciencedirect.com/science/article/pii/s0378382099000107 https://www.sciencedirect.com/science/article/pii/s0378382099000107 https://www.sciencedirect.com/science/article/pii/s0378382099000107 https://www.sciencedirect.com/science/article/pii/s0378382099000107 https://www.sciencedirect.com/science/article/abs/pii/s0016236116310705 https://www.sciencedirect.com/science/article/abs/pii/s0016236116310705 https://www.sciencedirect.com/science/article/abs/pii/s0016236116310705 https://www.sciencedirect.com/science/article/abs/pii/s0016236116310705 http://www.ijfac.unsri.ac.id/index.php/ijfac/article/view/121 http://www.ijfac.unsri.ac.id/index.php/ijfac/article/view/121 http://www.ijfac.unsri.ac.id/index.php/ijfac/article/view/121 http://www.ijfac.unsri.ac.id/index.php/ijfac/article/view/121 http://www.ijfac.unsri.ac.id/index.php/ijfac/article/view/121 https://link.springer.com/article/10.1007/s10973-021-10841-z https://link.springer.com/article/10.1007/s10973-021-10841-z https://link.springer.com/article/10.1007/s10973-021-10841-z https://link.springer.com/article/10.1007/s10973-021-10841-z https://link.springer.com/article/10.1007/s10973-021-10841-z https://link.springer.com/article/10.1007/s10973-021-10841-z https://doi.org/10.1007/s10973-021-10841-z https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.8b00428 https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.8b00428 https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.8b00428 https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.8b00428 https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.8b00428 https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.8b00428 https://doi.org/10.1021/acs.energyfuels.8b00428 https://pubs.acs.org/doi/abs/10.1021/acs.iecr.9b03346 https://pubs.acs.org/doi/abs/10.1021/acs.iecr.9b03346 https://pubs.acs.org/doi/abs/10.1021/acs.iecr.9b03346 https://pubs.acs.org/doi/abs/10.1021/acs.iecr.9b03346 https://pubs.acs.org/doi/abs/10.1021/acs.iecr.9b03346 https://pubs.acs.org/doi/abs/10.1021/acs.iecr.9b03346 https://pubs.acs.org/doi/abs/10.1021/acs.iecr.9b03346 https://doi.org/10.1021/acs.iecr.9b03346 http://www.heavyoilinfo.com/feature-items/heavy-crude-oil-a-global-analysis-and-outlook http://www.heavyoilinfo.com/feature-items/heavy-crude-oil-a-global-analysis-and-outlook https://pubs.acs.org/doi/abs/10.1021/ef050148+ https://pubs.acs.org/doi/abs/10.1021/ef050148+ https://pubs.acs.org/doi/abs/10.1021/ef050148+ https://pubs.acs.org/doi/abs/10.1021/ef050148+ https://pubs.acs.org/doi/abs/10.1021/ef050148+ https://www.sciencedirect.com/science/article/abs/pii/s0920586113003787 https://www.sciencedirect.com/science/article/abs/pii/s0920586113003787 https://www.sciencedirect.com/science/article/abs/pii/s0920586113003787 https://www.sciencedirect.com/science/article/abs/pii/s0920586113003787 https://www.sciencedirect.com/science/article/abs/pii/s0920586113003787 https://www.sciencedirect.com/science/article/abs/pii/s0920586113003787 https://www.sciencedirect.com/science/article/abs/pii/s026387620773071x https://www.sciencedirect.com/science/article/abs/pii/s026387620773071x https://www.sciencedirect.com/science/article/abs/pii/s026387620773071x https://www.sciencedirect.com/science/article/abs/pii/s026387620773071x https://www.sciencedirect.com/science/article/abs/pii/s0016236198000477 https://www.sciencedirect.com/science/article/abs/pii/s0016236198000477 https://www.sciencedirect.com/science/article/abs/pii/s0016236198000477 https://www.sciencedirect.com/science/article/abs/pii/s0016236198000477 https://www.sciencedirect.com/science/article/abs/pii/s0920586198001497 https://www.sciencedirect.com/science/article/abs/pii/s0920586198001497 https://www.sciencedirect.com/science/article/abs/pii/s0920586198001497 https://pubs.acs.org/doi/abs/10.1021/ie1014074 https://pubs.acs.org/doi/abs/10.1021/ie1014074 https://pubs.acs.org/doi/abs/10.1021/ie1014074 https://pubs.acs.org/doi/abs/10.1021/ie1014074 https://www.tandfonline.com/doi/abs/10.1080/01614949108020302 https://www.tandfonline.com/doi/abs/10.1080/01614949108020302 https://www.tandfonline.com/doi/abs/10.1080/01614949108020302 https://pubs.acs.org/doi/abs/10.1021/ie201202b https://pubs.acs.org/doi/abs/10.1021/ie201202b https://pubs.acs.org/doi/abs/10.1021/ie201202b https://pubs.acs.org/doi/abs/10.1021/ie201202b https://pubs.acs.org/doi/abs/10.1021/ie201202b https://pubs.acs.org/doi/abs/10.1021/ie201202b https://pubs.acs.org/doi/abs/10.1021/ie050202+ https://pubs.acs.org/doi/abs/10.1021/ie050202+ https://pubs.acs.org/doi/abs/10.1021/ie050202+ a. g. olaremu et al. / iraqi journal of chemical and petroleum engineering 22,2 (2021) 7 16 16 [40] fumoto, e.; matsumara, a.; sato, s.; takanohashi, (2010) “oxidative cracking of residual oil with iron oxide catalyst in a steam atmosphere”. prepr. am. chem. soc., div. pet. chem 50,50. [41] barbour, r. v., dorrence, s. m., vollmer, t. l. and harris, j. d. (1976) ‘pyrolysis of utah tar sands, products and kinetics’, presented at confab 1976. university of wyoming science, camp, usa. 19.-24 july. [42] ebrahimi, s., j.s. moghaddas , and m.k. razavi aghjeh(2008) ‘study on thermal cracking behavior of petroleum residue’fuel 87 : 1623–1627. [43] al soufi hh, savaya zf, moahummed hk, alazami ia.(1988) “thermal conversion (visbreaking) of heavy iraqi residue”. fuel 67:1714–5. [44] singh j, kumar mm, saxena ak, kumar s.(2004) “studies on thermal cracking behavior of residual feedstocks in a batch reactor”. chem eng sci.59:4505–15. [45] marsh h, martinez-escandell m, rodriguezreinoso f.(1999) “semicokes from pitch pyrolysis: mechanisms and kinetics”. carbon.37:363–90. [46] vyazovkin s. (2003) “reply to ‘what is meant by the term ‘variable activation energy’ when applied in the kinetics analyses of solid state decompositions (crystolysis reactions)?”.thermochim acta.397(12)269-71. [47] nashaat n.nassar, azfar hassan,german luna and pedro pereira-almao(2013) “comparative study on thermal cracking of athabasca bitumen” j therm anal calorim 114:465-472. [48] strausz. o.p., kamal n.jha and douglas s.montgomery(1977) “chemical composition of gases in athabasca bitumen and in low-temperature thermolysis of oil sand, asphaltene and maltene” fuel 56:114-120. https://www.sciencedirect.com/science/article/pii/s0009250909001973 https://www.sciencedirect.com/science/article/pii/s0009250909001973 https://www.sciencedirect.com/science/article/pii/s0009250909001973 https://www.sciencedirect.com/science/article/pii/s0009250909001973 https://www.sciencedirect.com/science/article/abs/pii/s0016236107003821 https://www.sciencedirect.com/science/article/abs/pii/s0016236107003821 https://www.sciencedirect.com/science/article/abs/pii/s0016236107003821 https://www.sciencedirect.com/science/article/abs/pii/0016236188902256 https://www.sciencedirect.com/science/article/abs/pii/0016236188902256 https://www.sciencedirect.com/science/article/abs/pii/0016236188902256 https://www.sciencedirect.com/science/article/pii/s0009250904004257 https://www.sciencedirect.com/science/article/pii/s0009250904004257 https://www.sciencedirect.com/science/article/pii/s0009250904004257 https://www.sciencedirect.com/science/article/pii/s0009250904004257 https://www.sciencedirect.com/science/article/abs/pii/s000862239800205x https://www.sciencedirect.com/science/article/abs/pii/s000862239800205x https://www.sciencedirect.com/science/article/abs/pii/s000862239800205x https://www.sciencedirect.com/science/article/abs/pii/s004060310200391x https://www.sciencedirect.com/science/article/abs/pii/s004060310200391x https://www.sciencedirect.com/science/article/abs/pii/s004060310200391x https://www.sciencedirect.com/science/article/abs/pii/s004060310200391x https://www.sciencedirect.com/science/article/abs/pii/s004060310200391x comparative%20study%20on%20thermal%20cracking%20of%20athabasca%20bitumen comparative%20study%20on%20thermal%20cracking%20of%20athabasca%20bitumen comparative%20study%20on%20thermal%20cracking%20of%20athabasca%20bitumen comparative%20study%20on%20thermal%20cracking%20of%20athabasca%20bitumen https://www.sciencedirect.com/science/article/abs/pii/0016236177901284 https://www.sciencedirect.com/science/article/abs/pii/0016236177901284 https://www.sciencedirect.com/science/article/abs/pii/0016236177901284 https://www.sciencedirect.com/science/article/abs/pii/0016236177901284 https://www.sciencedirect.com/science/article/abs/pii/0016236177901284 iraqi journal of chemical and petroleum engineering vol.18 no.1 (march 2017) 116 issn: 1997-4884 the effect of temperature on the synthesis of nano-gamma alumina using hydrothermal method abdul-halim a.k. mohammed 1 , hussein q. hussein 2 and mohammed sabah mohammed 3 1 gas and petroleum engineering department al-faraby university 2 chemical engineering department college of engineering baghdad university 3 office of assit. dean for scientific and student affairs al-nahrain university abstract nano gamma alumina was prepared by double hydrolysis process using aluminum nitrate nano hydrate and sodium aluminate as an aluminum source, hydroxyle poly acid and ctab (cetyltrimethylammonium bromide) as templates. different crystallization temperatures (120, 140, 160, and 180) 0 c and calcinations temperatures (500, 550, 600, and 650) 0 c were applied. all the batches were prepared at ph equals to 9. xrd diffraction technique and infrared fourier transform spectroscopy were used to investigate the phase formation and the optical properties of the nano gamma alumina. n2 adsorption-desorption (bet) was used to measure the surface area and pore volume of the prepared nano alumina, the particle size and the morphology of the surface of nano gamma alumina were estimated using afm and sem techniques ,respectively. all the samples represented pure nano gamma alumina with high crystalline and irregular hexagonal structure shape. the best results obtained were 456.5 m 2 /gm surface area, 0.49 cm 3 /gm pore volume, and 59.26 average particle size for the sample prepared at 180 0 c crystallization temperature, and 500 0 c calcinations temperature with nano spherical surface structure. key words: gamma alumina, nanoparticle, double hydrothermal, ctab. introduction aluminium oxide or alumina is the most cheap and effective oxide in the group of ceramic industry. alumina is used in ceramic and metal manufacturing due to its hardness, abrasion resistance, and heat resistance, used in synthesis of electronic circuits due to its electrical insulation and low thermal conductivity [1]. supported nano alumina with high surface area and pore volume is used extensively as catalyst, catalytic supports, and adsorbent for chemical processes. the surface of the nanoparticles plays an important role in their catalytic properties [2, 3, and 4]. different methods were used to prepare nano gamma alumina like; sol gel, hydrothermal treatment, precipitation, lazeroblation, solution composition, spraypyrolysis…etc [5, 6, 7 and 8]. the starting materials of synthesis nano gamma alumina are either university of baghdad college of engineering iraqi journal of chemical and petroleum engineering the effect of temperature on the synthesis of nano-gamma alumina using hydrothermal method 2 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net expensive and sensitive to moisture content like aluminium alkoxides or cheap and available materials like aluminium salts, clays, and pure aluminium powder [4]. to produce nanoparticle with optimum conditions of purity, high surface area, and pore volume different structure-direct-agent like surfactant and others were used in the synthesis using either room temperature (sol gel) method or high temperature over 100 0 c (hydrothermal treatment) by auto-clave reactors or microwave irradiation [9, 10]. using of surfactant-sol gel-technique is accompanied with some problems during process represented by the fast condensation of the mixtures causes cracks of prepared gel and phase transformation by the thermal treatment during eliminating of surfactant rather than hydrothermal treatment [11]. few reports were recognized using hydrothermal technique to prepare nano alumina like; ming bao et.al. 2010 prepared nano gamma alumina in the presence of two sources of alumina, ctab as surfactant, citria acid and different molar ratios of sodium citrate by double hydrothermal treatment using auto clave with temperature 170 0 c for 24 hrs, the optimum results acting in 0.2 molar ratio of sodium citrate with respect to aluminium salts with surface area 398 m 2 /gm, and pore volume 0.59 m 2 /gm [12]. xiang li et.al. 2011 [13] succeeded in the synthesis of nano gamma alumina using inorganic salt of alumina, ammonium carbonate, and 20000 molecular weight of peg by hydrothermal treatment with autoclave in the temperature 100 0 c for 24 hrs, and calcination temperature 500 0 c to produce nano gamma alumina with particle size between 10-38 nm, surface area 494 m 2 /gm, and pore volume 1.1 cm 3 . dahlan et.al. 2012 [14] prepared nano alumina adding urea as a fuel with molar ratio 29:153:1:2028 of aluminium salt, ctab, urea, and water using hydrothermal method producing 203 m 2 /gm, 0.14 cm 3 /gm of nano gamma alumina. faramawy et.al. 2014 [10] synthesis of nano gamma alumina by hydrothermal technique using microwave irradiation for the crystallization of aluminium salt and ctab surfactant and found that the increasing in the time and power of the reaction leads to increase the crystinallity and the texture properties of the prepared catalyst. hawraa 2016 [11] prepared nano gamma alumina with 56 nm, 256 m 2 /gm surface area, and 0.374 cm 3 /gm pore volume by sol gel method using aluminum chloride dissolved in ethanol and ammonia. the aim of this work is to prepare nano alumina by using double hydrothermal treatment method,and to study the effect of crystallization temperature and calcination temperature on the characterstics of prepared catalyst like; xrd, ftir, afm, surface area, pore volume, and sem. experimental work materials aluminum nitrate nonahydrate (al(no3)3.9h20, 100% purity), and sodium aluminate (naalo2, 100 % purity) were used as sources of aluminium. cetyltrimethylammonium bromide (ctab, 99% purity) was used as a surfactant, cirtic acid (ca, 100% purity) was used as a bridge between the aluminum source and the surfactant, and finally sodium hydroxide (naoh, 99% purity) was used to adjust the ph of the mixtures. preparation of nano alumina the nano gamma alumina was prepared by dissolving aluminium nitrate nonahydrate,citric acid and ctab surfactant in suitable amount of http://www.iasj.net/ abdul-halim a.k. mohammed, hussein q. hussein and mohammed sabah mohammed -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 3 dionized water, then sodium aluminate was dissolved in suitable amount of dionized water and added drop by drop to the first mixture under vigorous stirring (1000 rpm). the molar composition of the mixture al/ctab/citric acid/h2o is 1.0/0.1/0.2/125, a white gel formed immediately, after further stirring for 3 hrs, the mixtures adjusted at ph equal to 9. the produced gel was then placed in a teflon-lined stainless steel auto clave to start the crystallization at different crystallization temperatures 120-180 0 c for 12 hrs. the crystallization product was filtered using nano filter papers (slow), and washed by deionized water and ethanol for several times to eliminate the contaminants. alumina powders produced from various crystallization conditions were dried at temperature 100 0 c for 24 hrs, and calcined at 600 0 c, while nano alumina which is crystallized at 180 0 c calcined at different calcination temperatures 500650 0 c to study the effect of the calcination temperature besides the crystallization temperatures on the characteristics of the prepared nano alumina. characterization of nano the structure of the samples was obtained by x-ray diffraction analysis in the ministry of science and technology. analysis was carried out using x-ray diffract meter type shimadzu srd 6000, japan, with cu wave length radiation (1.54060) in the 2 theta range from 10-80 0 , and fixed power source (40kv, 30ma). to study the functional groups and the characteristics of the bonds of the prepared samples fourior –transform infrared spectroscopy (ftir) applied using (ir-affinity,s himazdo, japan) with wave range between 400-4000 cm -1 loacated at the university of baghdad /college of science / central environmental laboratory, the samples were made by pressing the to disk shape after added 1% nano alumina to 99% kbr. the texture properties surface area, and pore volume) of the samples were conducted at the petroleum research and development center in baghdad using brunauer emmett and teller (bet) method with thermo analyzer/usa. the average particle size and the morphology of surface of each sample were calculated at the university of baghdad /college of science /department of chemistry using atomic force microscope device (type angstrom, scanning probe microscope, advanced inc, aa 3000, usa). the morphology of the structure of nano gamma alumina was studied using fei nova nano sem device located at chemical engineering department / tehran university. the specimen of prepared nano gamma alumina was dispersed in ethanol and coated by gold using special cell. results and discussions x-ray diffraction (xrd) from the figures 1 to 7 it is clear that all the prepared samples represent gamma-alumina after comparison with international alumina card (jcpds) files no. (29. 0063) where they were accepted the three strong standard peaks of gamma alumina (311-65b intensity -2.39 d spacing), (400-80b intensity-1.98 d spacing), and (410-100 b intensity-1.4 d spacing) which represents the substantial crystallization. these figures represent the high crystalline gamma alumina because the ph of the operation condition is over 8 while using ph under 8 leads to produce beta alumina which very easy transform to alpha alumina after thermal treatment [16]. it is clear that the broading of the peaks http://www.iasj.net/ the effect of temperature on the synthesis of nano-gamma alumina using hydrothermal method 4 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net occurs due to the role of the ctab surfactant used in the process producing nano particle size while the surfactant is released after calcinations [17, 18]. the increasing in crystallization temperature from 120 0 c to 180 0 c in figures 1 to 4 leads to more matching of the (d) spacing and the intensity between the standard peaks and the peaks of the samples prepared, and any increasing in crystallization temperature leads to increase the intensity (crystinallity) and some of the particles were solubilized and grain growth occurred causes enlargement of the crystal size [19].the increasing in calcinations temperature figures 4 to 7 causes increasing in crystinallity of the prepared samples beginning from 500 0 c which represents width of the peaks due to low crystinallity to the high crystalline and sharp peaks in the calcinations temperatures 600, 650 0 c [19, 20]. fig. 1: xrd diffraction of nano gamma alumina prepared at 120 0 c crystallization temperature and 600 0 c calcination temperature fig. 2: xrd diffraction of nano gamma alumina prepared at 140 0 c crystallization temperature and 600 0 c calcination temperature http://www.iasj.net/ abdul-halim a.k. mohammed, hussein q. hussein and mohammed sabah mohammed -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 5 fig. 3: xrd diffraction of nano gamma alumina prepared at 160 0 c crystallization temperature and 600 0 c calcination temperature fig. 4: xrd diffraction of nano gamma alumina prepared at 180 0 c crystallization temperature and 600 0 c calcination temperature fig. 5: xrd diffraction of nano gamma alumina prepared at 180 0 c crystallization temperature and 500 0 c calcination temperature http://www.iasj.net/ the effect of temperature on the synthesis of nano-gamma alumina using hydrothermal method 6 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net fig. 6: xrd diffraction of nano gamma alumina prepared at 180 0 c crystallization temperature and 550 0 c calcination temperature fig. 7: xrd diffraction of nano gamma alumina prepared at 180 0 c crystallization temperature and 650 0 c calcination temperature fourier transport infrared (ftir) ftir-spectra of the prepared nano gamma alumina are shown in figures from 8 to 14 shows large bands in the region between 400-1000 cm -1 represent the stretching vibration of al-o-al bands, the broad bands between 500-750 cm -1 refers to gamma alumina with nanoparticle size [17, 21]. the absence of bands around 1371cm -1 refers to absence of surfactant after calcination in the prepared samples [17], while the absence of bands around 1380 cm -1 refers that the samples are free from no2 after calcination which is clear from its white colour [7]. the bands around 1640 cm -1 and 3500 cm -1 represent the bending bands of oh bands [22], so that these results of broad bending and stretching bands leads to prepare pure nano gamma alumina which are in agreed with the results obtained from xrd diffraction. http://www.iasj.net/ abdul-halim a.k. mohammed, hussein q. hussein and mohammed sabah mohammed -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 7 fig. 8: ftir-spectra of the nano gamma alumina prepared at 120 0 c crystallization temperature and calcination temperature 600 0 c fig. 9: ftir-spectra of the nano gamma alumina prepared at 140 0 c crystallization temperature and calcinations temperature 600 0 c fig. 10: ftir-spectra of the nano gamma alumina prepared at 160 0 c crystallization temperature and calcinations temperature 600 0 c 500750100012501500175020002500300035004000 1/cm 10 20 30 40 50 60 70 80 %t 3 4 7 9 .5 8 3 4 2 3 .6 5 1 6 4 1 .4 2 8 0 0 .4 6 5 8 0 .5 7 4 7 2 .5 6 4 2 0 .4 8 ft ir measurement 500750100012501500175020002500300035004000 1/cm 15 22.5 30 37.5 45 52.5 60 67.5 75 82.5 %t 34 62 .2 2 34 62 .2 2 29 45 .3 0 23 51 .2 3 16 43 .3 5 15 31 .4 8 74 0. 67 57 2. 86 43 2. 05 ft ir measurement 500750100012501500175020002500300035004000 1/cm 20 30 40 50 60 70 80 90 %t 34 56 .4 4 34 56 .4 4 29 31 .8 0 23 60 .8 7 16 41 .4 2 15 17 .9 8 78 5. 03 57 6. 72 ft ir measurement http://www.iasj.net/ the effect of temperature on the synthesis of nano-gamma alumina using hydrothermal method 8 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net fig. 11: ftir-spectra of the nano gamma alumina prepared at 180 0 c crystallization temperature and calcinations temperature 600 0 c fig. 12: ftir-spectra of the nano gamma alumina prepared at 180 0 c crystallization temperature and calcinations temperature 500 0 c fig. 13: ftir-spectra of the nano gamma alumina prepared at 180 0 c crystallization temperature and calcinations temperature 550 0 c 500750100012501500175020002500300035004000 1/cm 30 37.5 45 52.5 60 67.5 75 82.5 %t 37 32 .2 6 34 62 .2 2 34 60 .3 0 23 51 .2 3 16 51 .0 7 15 17 .9 8 73 6. 81 57 8. 64 44 1. 70 ft ir measurement 500750100012501500175020002500300035004000 1/cm 10 20 30 40 50 60 70 80 90 %t 3 4 5 6 .4 4 3 4 5 6 .4 4 2 3 5 8 .9 4 1 6 4 1 .4 2 1 5 1 7 .9 8 1 4 0 6 .1 1 7 8 5 .0 3 7 8 5 .0 3 5 8 6 .3 6 4 2 0 .4 8 ft ir measurement 500750100012501500175020002500300035004000 1/cm 20 30 40 50 60 70 80 %t 3 4 5 6 .4 4 3 4 5 6 .4 4 2 9 3 3 .7 3 2 3 6 2 .8 0 1 6 4 3 .3 5 1 5 1 6 .0 5 1 4 0 6 .1 1 7 6 3 .8 1 6 2 4 .9 4 5 8 6 .3 6 ft ir measurement http://www.iasj.net/ abdul-halim a.k. mohammed, hussein q. hussein and mohammed sabah mohammed -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 9 fig. 14: ftir-spectra of the nano gamma alumina prepared at 180 0 c crystallization temperature and calcinations temperature 650 0 c surface area and pore volume the surface area and pore volume of the nano catalyst play a very important role for the activity of the nano catalyst, because high surface area leads to high active sites causes increasing in activity. table 1 shows the results of surface area and pore volume of the samples for different conditions. table 1: the values of surface area and pore volume at different crystallization and calcinations temperatures crystallization temp. 0 c calcination temp. 0 c surface area (m 2 /gm) pore volume (cm 3 /gm) 120 0 c 600 0 c 352 0.47 140 0 c 600 0 c 356.37 0.4598 160 0 c 600 0 c 359.37 0.4548 180 0 c 600 0 c 383.01 0.43 180 0 c 500 0 c 456.5 0.49 180 0 c 550 0 c 401.02 0.53 180 0 c 650 0 c 338.93 0.43 in spite of that the increasing of the crystallization temperature leads to densification of some of the pores reducing the pore volume but the surface area still increased due to the dispersion role of the surfactant [23]. the increasing of calcinations temperature causes decreasing in the surface area and pore volume values because at low calcination temperature about 500 0 c the dehydroxelation begins and the bonds of h2 atoms eliminated causes increasing in surface area reached to 456 m 2 /gm which is higher than the results obtained by ming 2010 [13], while in the temperature of 600 0 c and above the particles become [close to each other’s causes agglomeration and reduce the open pores so that the surface area and pore volume of the samples decreased [24]. particle size and the morphology of the catalyst the atomic force microscopy (afm) method was used to find the average particle size, particle size distribution and the shape of the surface, and the results of the particle size are listed in table 2. the average particle size of the prepared nano alumina was in the nano scale catalyst for all crystallization temperatures. the increasing in crystallization temperature from 120 0 c to 180 0 c at constant calcinations temperature 600 0 c leads to increase the average particle size gradually from 90.56 nm to 92.72 nm with little effect in the temperature between 140 0 c to 160 0 c. this behavior causes gradual rising in surface area associated with drop in pore volume reaches to its high values at a temperature 180 0 c. 500750100012501500175020002500300035004000 1/cm 30 37.5 45 52.5 60 67.5 75 82.5 %t 38 76 .9 2 37 38 .0 5 34 56 .4 4 34 56 .4 4 28 68 .1 5 23 60 .8 7 17 76 .4 4 16 45 .2 8 15 46 .9 1 14 21 .5 4 78 5. 03 78 5. 03 64 0. 37 57 6. 72 47 4. 49 ft ir measurement http://www.iasj.net/ the effect of temperature on the synthesis of nano-gamma alumina using hydrothermal method 10 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net increasing the calcination temperature from 500 0 c to 650 0 c leads to very high enlargement from 59.26 nm to 93.84 nm causes increasing in surface area associated in decreasing in pore volume. in the calcination temperatures 500 0 c and 550 0 c the pores between the particles are opened cause high surface area and pore volume, while any increasing in calcinations temperature causes blockage in these pores reaching to the sentring. these results are near the results obtained by hawraa 2016 [11]. figure 15 represents the two dimension surface morphology of the prepared samples with non spherical structure, while figure 16 represents the three dimension surface morphology of the prepared samples with hexagonal layers. table 2: the values of particle size distribution and average particle size at different crystallization and calcinations temperatures crystallization temperature 0 c calcination temperature 0 c particle size distribution, nm average particle size, nm 120 0 c 600 0 c 30-145 90.56 140 0 c 600 0 c 45-125 92.15 160 0 c 600 0 c 20-155 92.57 180 0 c 600 0 c 75-160 92.72 180 0 c 500 0 c 50-110 59.26 180 0 c 550 0 c 30-85 59.53 180 0 c 650 0 c 93.84 75-125 (a) (b) (c) (d) (e) (f) (g) fig. 15: afm images for samples [a-d at t=120-180 °ccrystallization temperature, time=12 h,600 0 c calcination temperature,e-f at180 °ccrystallization temperature, time=12 h,500,550,650 0 c calcination temperature http://www.iasj.net/ abdul-halim a.k. mohammed, hussein q. hussein and mohammed sabah mohammed -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 11 (a) (b) (c) (d) (e) (f) (g) fig. 16: afm three – dimensional surface profile for samples [a-d at t=120-180 °c crystallization temperature, time=12 h,600 0 c calcination temperature, e-f at180 °c crystallization temperature, time=12 h, 500,550,650 0 c calcination temperature scanning electron microscopy (sem) the effect of crystallization and calcination temperatures is shown in figures 17 to 23. at 120 0 c non uniform shape of particles is observe .using crystallization temperature between 140-180 0 c leads to crystal growth with low agglomeration and uniform irregular hexagonal shape and size because of the active role of ctab surfactant in these temperatures as mentioned by kianinia 2014 and dahlan . 2012 [24, 25]. fig. 17: sem image of the nano gamma alumina prepared using citric acid at 120 0 c crystallization temperature, 12hrs crystallization time and calcination temperature 600 0 c http://www.iasj.net/ the effect of temperature on the synthesis of nano-gamma alumina using hydrothermal method 12 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net fig. 18: sem image of the nano gamma alumina prepared using citric acid at 140 0 c crystallization temperature, 12hrs crystallization time and calcination temperature 600 0 c fig. 19: sem image of the nano gamma alumina prepared using citric acid at 160 0 c crystallization temperature,12hrs crystallization time and calcination temperature 600 0 c fig. 20: sem image of the nano gamma alumina prepared using citric acid at 180 0 c crystallization temperature,12hrs crystallization time and calcination temperature 600 0 c http://www.iasj.net/ abdul-halim a.k. mohammed, hussein q. hussein and mohammed sabah mohammed -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 13 fig. 21: sem image of the nano gamma alumina prepared using citric acid at 180 0 c crystallization temperature, 12hrs crystallization time and calcination temperature 500 0 c fig. 22: sem image of the nano gamma alumina prepared using citric acid at 180 0 c crystallization temperature, 12hrs crystallization time and calcination temperature 550 0 c fig. 23: sem image of the nano gamma alumina prepared using citric acid at 180 0 c crystallization temperature, 12hrs crystallization time and calcination temperature 650 0 c http://www.iasj.net/ the effect of temperature on the synthesis of nano-gamma alumina using hydrothermal method 14 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net at 500 0 c fine nano particles with low agglomeration is observed. increasing the calcination temperature above 500 0 c makes the particles close to each others causes increasing in particle size and decreasing in surface area and pore volume as mentioned by amirsalari a. 2015 [26]. conclusions nano gamma alumina was successfully synthesized using double hydrothermal method in the presence of ctab surfactant and citric acid. different techniques were used to characterize the prepared samples with different crystallization and calcination temperature. xrd diffractions and ftir-spectra represent the crystalline nano gamma alumina pure from surfactant. the surface area increased during increasing of crystallization temperature and decreased during increasing calcinations temperature, while pore volume was increased with the rising of the crystallization and calcinations temperature. all the prepared samples were in the nano scale particle size with irregular hexagonal surface structure, and this morphology is the same with the morphology acting by hawraa 2016 [11]. references 1. amirsalari a.,and farjami shayesteh, 2015, "effect of ph and calcinations temperature on structure and optical properties of alumina nanparticle" , j. of superlattics and microstructure,department of physics, university of guilan, iran,vol.82,pp.507-524. 2. marino f.,descorme c.,and duprez d.,2005,"supported base metal catalysts for the preferential oxidation of carbon monoxide in the presence of excess hydrogen",j. of appl.cat. vol.58,pp.175-183. 3. carmo m.,paganin v.a.,roselen j.m.,2005,"alternative supports for the preparation of catalysts for low temperature fuel cells:the use of carbon nanotubes",j. of power sources,vol.142,pp.169-176. 4. parida, k.m., and amaresh c., 2009,"synthesis and characterization of nano-sized porous gamma –alumina by control precipitation method", institute of minerals and materials technologies, india, vol (113), 244248. 5. chengchao liu,jinlin li,kongyong liew,and junjiang zhu,2012,"an enviromental friendly method for the synthesis of nano-alumina with controllable morphologies",j. of rcs advances,vol.2,pp.8352-8358. 6. veeradate piriyawong,voranuch thongpool,and piyapong asanithi,2012,"praparation and characterization of alumina nanoparticles in deionized water using lazer ablation technique",j. of nanomaterials,article id 819403,6pages. 7. bustan afruz a.,and tafreshi m.j.,2014,"synthesis of gamma alumina nanoparticle by different combustion modes using ammonium carbonate",indian j. of pure and applied physics,vol.52,pp.378-385. 8. yousif jawad,2009,"synthesis and characterization of zeolite nanoparticles catalysis used for nhexane conversion.",phd thesis,university of baghdad,college of engineering,chemical engineering department. 9. mandana akia,sayad mahdi alavi,and zi feng yan,2010,"promoted platinum dehydrogenation catalyst on a nanosized gamma alumina support",j. of http://www.iasj.net/ abdul-halim a.k. mohammed, hussein q. hussein and mohammed sabah mohammed -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 15 petroleum and coal,vol.52,pp.280289. 10. faramawy s.,el-shall m. s.,and abd el wahed m.g.,2014"synthesis of high surface area gamma alumina by microwave irradiation process",j. of american science,vol.10,pp.9. 11. hawraa h.,2016," preparation of nano ni-mo/ϒ-al2o3 catalyst for hydrodesulphurization of iraqi gas oil", msc.thesis,chemical engineering department,college of engineering,university of baghdad. 12. mandana akia,sayad mahdi alavi,and zi feng yan,2011,"dehydrogenation catalysts of higher normal paraffins on a nanocrystalline gamma alumina:different impregnation sequences",j. of petroleum and gas eng.,vol.2,no.3pp.64-73. 13. ming bo yue,wen qian jiao,yi meng wang,and ming yuan he ,2010,"ctab-directed synthesis of mesopores gamma alumina promoted by hydroxyl polyacids",j.of micro.,and meso. mat., vol.132, pp.226-231. 14. xiang li,dezhi han,and zifeng yan,2011,"a simple hydrothermal route to bimodal mesoporous nanorod gamma alumina with high thermal stability",int. j. of mat. research,pp.1473-1476. 15. dahlan,i nyoman marsih,and joonjai panpranot,2012,"gamma alumina nanotubes prepared by hydrothermal method as support of iron,cobalt,and nickel for fischertropsch catalysts",j. of chemistry and materials research,vol.2,no.3,pp.31-38. 16. jian hong yi,son you yi,and gao jian feng,2009,"synthesis of crystalline gamma alumina with high purity",j.of nanoferrous matrials society ,china,vol.19,pp.1237-1242. 17. kianinia y.,darban a.k.,and rahnama b.,2014,"synthesis of nano sized mesoporous gamma alumina powder from domestic hamedan kaolin",iranian j. of materials and eng.,vol.12,no.1,pp.59-65. 18. aguado j.,escola j. m.,and castro m.c.,2005,"sol-gel synthesis of nanostructured gamma alumina templated by cationic surfactant",j. of micro. and meso. mater.,vol.82,pp.181-192. 19. marzieh jalilpour,and mohammad fathalilou,2012,"effect of aging time and calcination temperature on the cerium oxide nanoparticles synthesis via reverse co-precipitation method",int. j. of physics and science,vol.7,no.6,pp.944-948. 20. baichao an,guijun ji,and guanghuan li,2010,"azeotropic distillation assisted preparation of nanoscale gamma alumina powder from waste oil shale ash",j. of chem. eng. ,vol.157,pp.67-72. 21. parida k. m.,amaresh c. pardhan,2009,"synthesis and characterization of nano-sized porous alumina by control precipitation method",j. of mater. chem..and physic.,vol.113,pp.244248. 22. shuchismita dey, 2010,"synthesis and application of gamma alumina nanopowder",msc thesis,national institute of technology,rourkela. 23. hyun chul lee,hae jin kim,and chang houn rhee,2005,"synthesis of nanostructured gamma alumina with a cationic surfactant and controlled amounts of water",j. of meso. and micro. mater.,vol.79,pp.61-68. 24. padmaja p.,krishina pillai,2004,"adsorption isotherm and pore characteristics of nano alumina derived from sol-gel http://www.iasj.net/ the effect of temperature on the synthesis of nano-gamma alumina using hydrothermal method 16 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net boehmite",j. of porous mater.,vol.11,pp.147-155. 25. kianinia y.,darban a.k.,and rahnama b.,2014, "synthesis of nano sized mesoporous gamma alumina powder from domestic hamedan kaolin" ,iranian j. of materials and eng.,vol.12,no.1,pp.59-65. 26. dahlan,i nyoman marsih,and joonjai anpranot,2012,"gamma alumina nanotubes prepared by hydrothermal method as support of iron, cobalt, and nickel for fischertropsch catalysts" , j. of chemistry and materials research,vol.2,no.3,pp.31-38. 27. amirsalari a.,and farmaji s.,2015,"effect of ph and calcination temperature on structure and optical properties of alumina nanoparticles"j.of suprelattics and microstructures,vol.82,pp.507-524. http://www.iasj.net/ iraqi journal of chemical and petroleum engineering vol.16 no.4 (december 2015) 1119 issn: 1997-4884 esterification of free fatty acid with high chain alcohol for biodiesel production using semi-batch reactive distillation wadood t. mohammed and marwa f. abdul jabbar* chemical engineering department – college of engineering – university of baghdad *chemical engineering department-college of engineering-al-nahrain university abstract the esterification of oleic acid with 2-ethylhexanol in presence of sulfuric acid as homogeneous catalyst was investigated in this work to produce 2-ethylhexyl oleate (biodiesel) by using semi batch reactive distillation. the effect of reaction temperature (100 to 130°c), 2-ethylhexanol:oleic acid molar ratio (1:1 to 1:3) and catalysts concentration (0.2 to 1wt%) were studied. higher conversion of 97% was achieved with operating conditions of reaction temperature of 130°c, molar ratio of free fatty acid to alcohol of 1:2 and catalyst concentration of 1wt%. a simulation was adopted from basic principles of the reactive distillation using matlab to describe the process. good agreement was achieved. key words: biodiesel, reactive distillation, esterification, homogeneous catalyst introduction sustainable energy management is a major concern of the modern society. the increasing energy demand makes the implementation of sustainable fuels a crucial issue worldwide [1,2]. biodiesel has become increasingly attractive because it is made from renewable sources and combines high performance with environmental benefits [3–5]. unlike petroleum diesel that contains hydrocarbons, biodiesel consists of a mixture of monoalkyl esters of long-chain fatty acids. biodiesel has several advantages over petroleum diesel: it is safe, renewable, nontoxic and biodegradable; it contains no sulfur that effected lubricity prolongates the diesel engine life [2,5]. biodiesel not only has a higher cetane number than petroleum diesel but also has a higher flash point, meaning better and safer performance and it generates less hydrocarbons, fewer carbon dioxide and fewer particles than petroleum diesel. biodiesel can be blended with any amounts of petroleum diesel and defined by a “b” followed by the vol % of biodiesel [4]. the conventional biodiesel production process based on the use of alkaline catalyst, such as sodium hydroxide or sodium methoxide, for transesterification of triglyceride posed serious separation problem. the presence of water and/or free fatty acids (ffa) in the reaction system leads to saponification [6-8]. a homogeneous acid catalyst, such as sulfuric acid or hydrochloric acid can also be used [9,10], which does not produce soap and increase the fuel production. meher et.al. suggested an alternative way to solve the ffa iraqi journal of chemical and petroleum engineering university of baghdad college of engineering esterification of free fatty acid with high chain alcohol for biodiesel production using semi-batch reactive distillation 12 ijcpe vol.16 no.4 (dec. 2015) -available online at: www.iasj.net problem by using an acid catalyst. the esterification of ffa by methanol can be carried out before the transesterification of oil as shown in eq. 1 [11]. thus, valuable ffas can be completely converted to biodiesel without being wasted. rcooh + ch3oh = rcooch3 + h2o ... (1) there are five primary ways for making biodiesel: (i) direct use and blending of vegetable oil (ii) use of microemulsions with short-chain alcohols (iii) thermal cracking (pyrolysis) of vegetable oils (iv) transesterification of triglycerides catalyzed by bases, acids, or enzymes and (v) esterification of fatty acids with alcohols, using acid catalysts (h2so4) or solid acids. usually, an alcohol excess is used for driving the reaction equilibrium towards the product side. this alcohol excess must be recovered in order to reutilize it and furthermore purify the biodiesel. the alcohol recovery process is generally carried out by distillation process, thus, the energy consumption, operating costs, equipment number and the production time increase. reactive distillation (rd) is the process in which chemical reaction and separation are carried out simultaneously within a fractional distillation apparatus. it may be advantageous for liquid-phase reaction systems when the reaction must be carried out with a large excess of one or more of the reactants, when a reaction can be driven to completion by removal of one or more of the products as they are formed, or when the product recovery or by-product recycle scheme is complicated or made infeasible by azeotrope formation [12]. by continuous separation of products from reactants while the reaction is in progress, the reaction can proceed to a much higher level of conversion than without separation [13]. the aim of this work is the study of the production of biodiesel by esterification of oleic acid with 2ethylhexanol in a reactive distillation column. the esterification of oleic acid using sulfuric acid as a catalyst has been investigated at different process conditions: temperature, oleic acid: 2ethylhexanol ratio, sulfuric acid concentrations. experimental section materials oleic acid (98%) was supplied from thomas baker, india. this acid is unsaturated fatty acid that jatropa oil which is inedible oil contains 44.8% of it. 2-ethylhexanol alcohol (99% from gc analysis) was maintained from ministry of science and technology as industrial alcohol. since this alcohol is typically a waste alcohol from the manufacturing of butanol, this process makes sense from an economic viewpoint. sulfuric acid as catalyst, ethanol and phenolphthalein for titration. reaction procedure the reaction was carried out in a lab scale reactive distillation column that consists of a 250 ml flask equipped with oil bath to set up a constant reaction temperature, magnetic stirrer, condenser, and column distillation. the feed is charge into the flask in the bottom of the rectifying column that also used as a reactor and reboiler. esterification of fatty acid is a reversible reaction and water is formed. removal of water can drive the reaction equilibrium to the completion and therefore increase the conversion. the best solution is working at temperatures above 100°c, in a system with continuous water wadood t. mohammed and marwa f. abdul jabbar -available online at: www.iasj.net ijcpe vol.16 no.4 (dec. 2015) 13 removal. by removing water as byproduct, the equilibrium is shifted towards ester formation. the ester (biodiesel) will always be separated in the bottom of the reactive distillation column. water is present as side product and typically is removed as top product due to its lower boiling point. 5 ml of diluted solution was taken for the determination of unreacted acid. this was titrated against 0.1 koh solution using phenolphthalein as indicator and 2 ml ethanol for dilution. difference between the fresh acid reading and reading for reaction mixture was used for finding out the % yield of ester. acid value = ... (2) x%= (1 ) 100 ... (3) and the amount of catalyst used is normalized to the total amount of reactants: in these equations, v, n and m.wt is volume, concentration and molecular weight of koh, m is weigh of sample. x [%] is the conversion of the fatty acid, [acid]initial and [acid]final are the molar concentrations of fatty acid before and after reaction, wcat [%] is the weight percent of catalyst used in reaction and mcat, macid and malcohol are the amounts of catalyst, acid and alcohol, respectively. simulation process to develop a mathematical model of reactive distillation for biodiesel production, mass balance as well as the thermodynamic equilibrium equations on each tray is written. the stages are counted from top to bottom as shown in fig. (1). the model is valid under the following assumptions: i. all the plates are equilibrium stages. ii. vapor phase is an ideal gas mixture. iii. the reaction takes place only in the reboiler, therefore, rate of reaction just added for reboiler equation. iv. constant operating pressure v. vapor phase hold up is assumed to be negligible as compared to the liquid phase hold up on each stage. vi. the column was considered isothermal (temperature for all stages is the same) therefore energy balance not established. fig. 1, scheme of semi-batch distillation column the column was simulated assuming 4 stages including the reboiler. the feed was introduced at the reboiler and the reaction took place in reboiler. the simulation was carried out by solving the system simultaneously using matlab program. the determination of phase composition can be made by solution of material balance equations. the solution of material balance equations are derived for condenser, the column stages and reboiler as follow: esterification of free fatty acid with high chain alcohol for biodiesel production using semi-batch reactive distillation 14 ijcpe vol.16 no.4 (dec. 2015) -available online at: www.iasj.net • for condenser (k=1, i=1-4) = ... (5) • for column (k=2,3and i=1-4) = ( + ( ... (6) • for reboiler (k=n and i=1-4) = +rate... (7) where h is holdup, k is stage, i is component equilibrium ratio (k=2 to n) = ∑ … (8) where αi is the relative volatility x is composition of liquid phase y is composition of vapor phase the uniquac model was applied to consider the nonideal liquidphase behavior. the degree of deviation from ideality in liquid phase is represented by γi (activity coefficient). it was employed for the vapor–liquid equilibrium (vle) calculations in matlab. activity coefficient consists of two terms, residual and combinatorial lnγi= ln + ln ... (9) ln = 1ji +ln ji -5qi (1 + ln ) ... (10) ln = [ 1∑ ˗ ln )] ... (11) results and discussion 1effect of mixing speed fig. (2) illustrates the relationship between conversion of oleic acid with time at different mixing speeds (500900 rpm) using a homogeneous catalyst of concentration of 1wt%, reaction temperature of 130°c and oleic acid:2-ethylhexanol molar ratio of 1:1. the results obtained here, showed that the conversion increased from 91.78 to 96.55% for mixing speed of 500 to 650 rpm respectively, then decreasing to 93.97% for mixing speed of 900 rpm. when the speed is higher than the desired one which gave high conversion, there was a negative effect because of the formation of very small droplet that behave as rigid drop, causing the molecules inside the drop could not move and transferred from center of drop to surface to be converted, therefore the reaction and conversion took place only on the surface which gave lower value. fig. 2, effect of mixing speed on conversion of oleic acid [operating conditions:molar ratio of free fatty acid: alcohol was 1:1, reaction temperature 130°c and concentration of sulfuric acid 1wt%] wadood t. mohammed and marwa f. abdul jabbar -available online at: www.iasj.net ijcpe vol.16 no.4 (dec. 2015) 15 2effect of molar ratio of alcohol to free fatty acid the most important parameter effect biodiesel production is molar ratio of alcohol to oil. for batch studies of conventional process the alcohol to oil ratio of feed has considered as an important factor for determining equilibrium constant and excess of alcohol used to shift the reaction to equilibrium. on contrast, reactive distillation used to overcome this problem since it reduce the need of excess alcohol and reduce the time by continuous removing of water instead of adding excess reactant. for oleic acid and 2-ethylhexanol using homogeneous catalyst (h2so4), fig.(3) shows the effect of molar ratio of 2-ethylhexanol: oleic acid on the conversion of oleic acid at a constant temperature of 130°c, concentration of sulfuric acid of 1wt% and mixing speed of 650 rpm. lt can be clearly seen the activity profile, when the molar ratio increased from 1 to 2 the conversion was found to increase from 78% to 97% after 20 min reaction time while for further increase in 2ethylhexanol ratio to 3, the conversion decrease to reach 93.40% after 2 h reaction time. as the alcohol to acid molar ratio varies to reach three orders of magnitude, dehydration to ethers is a potentially unwanted side reactions, the formation of alkene which cause decrease in conversion were occured. also further increasing in alcohol led to disturbing the stoichiometric of alcohol to acid and accordingly decreases in reaction rate. as well as the molar ratio of alcohol to acid increased, the catalyst was diluted by excess of alcohols this also led to decreased conversion. fig. 3, effect of acid:alcohol molar ratio on oleic acid conversion [operating conditions: reaction temperature 130°c, concentration of homogeneous catalyst 1wt% (h2so4) and mixing speed 650 rpm] 3effect of reaction temperature fig. (4) illustrates the variation of conversion with time at different reaction temperatures of 100, 110 120 and 130°c to enhance the separation of water. it has been observed as the temperature increase, the conversion increase from 93.34% at 100°c to reach 96.55% at 130°c after 10 min reaction time with constant molar ratio of oleic acid:2-ethylhexanol of 1:2 and catalyst amount of 1wt%. since the esterification reaction is endothermic, increasing the reaction temperature led to increasing conversion. the high temperature cause increase in activity of molecules which mean more molecules have more energy, therefore the probability of molecules to react increased. esterification of free fatty acid with high chain alcohol for biodiesel production using semi-batch reactive distillation 16 ijcpe vol.16 no.4 (dec. 2015) -available online at: www.iasj.net fig. 4, effect of temperature on oleic acid conversion 4effect of catalyst concentration the amounts of catalyst also play a role on the conversion of the esterification reaction but less effect than temperature and molar ratio. the varying amount of catalysts was studied in this work at the following reaction conditions: ratio of alcohol to fatty acid 2:1 , temperature 130°c and mixing speed of 650 rpm during 120 min of reaction time. the results are displayed in fig.(5) and shows that reaction was highly depend on presence of catalyst which accelerate the reaction. it gave 59.13% after 120 min. conversely, in the presence of acid catalysts, a different results were observed. therefore the conversion increased to reach 86% and 97% when the reaction catalyzed by 0.2wt% and 1wt% sulfuric acid respectively after 60 min. the increase in catalyst concentration considerably shortened the time needed to reach the reaction equilibrium. this in agreement with kusmiyati and sugiharto a., 2010, who studied the effect of concentration of sulfuric acid on esterification of oleic acid with methanol and showed that further adding of catalyst amount above 1wt% did not lead the conversion to increase significantly [14]. since sulfuric acid absorbs some of the water formed by reacting with it to form solvated ions, thus reducing the amount of free water in the system therefore the best concentration achieved was 1wt%. fig. 5, effect of homogeneous catalyst concentration on oleic acid conversion [operating conditions: reaction temperature 130°c, molar ratio of 2ethylhexanol:oleic acid 2:1 and mixing speed 650 rpm] testing of biodiesel obtained from oleic acid biodiesel obtained from oleic acid was analyzed by astm (american standard for testing material). table (1) shows biodiesel from this experiment table 1, petroleum diesel vs. biodiesel recent work[16] diesel [15] biodiesel [15] fuel properties 100 60–80 100–170 flash point °c 9659.5 1.3–4.1 1.9–6.0 kinematic viscosity (mm/s)@40°c 0.859 56.9 56.. density g/ml @30°c -10 -35 to – 15 -15 to 10 pour point °c -7 -15 to 5 -3 to 12 cloud point °c 198 188343 182-338 boiling point °c 0.136 carbon residue% wadood t. mohammed and marwa f. abdul jabbar -available online at: www.iasj.net ijcpe vol.16 no.4 (dec. 2015) 17 simulation results the predicted results from the simulation model of batch reactive distillation could be utilized to speculate the composition of reactants and products to compare them with experimental work. figs. (6) to (8) displaying the composition change with time for oleic acid with homogeneous catalyst at various conditions of temperature and molar ratio of alcohol to ffa with constant concentration of catalyst (1wt %). there are simple differences between theoretical and experimental results. the main deviation due to non ideality of a system which ignored in the experiment but considered for theoretical study. fig. (6) shows a decrease in mole fraction of oleic acid with time, which approached nearly zero within 5 min, this is due to the fact that is converted to biodiesel after the reaction reached its suitable conditions. fig. 6, mole fraction of oleic acid and its biodiesel [operating conditions: molar ratio alcohol: acid was 2:1, reaction temperature 130°c and concentration of homogeneous catalyst wt 1% (h2so4)] fig. 7, mole fraction of oleic acid and its biodiesel [operating conditions: molar ratio of alcohol:acid was 2:1, reaction temperature 100°c and concentration of homogeneous catalyst 1wt% (h2so4)] this result was in a good agreement with experimental results as shown in the figure. while for biodiesel, the mole fraction in still increased for both experiment and simulation, but simulation gave lower fraction as a result of water presence. at temperature 100°c at the same ratio of alcohol: acid of (2:1) very good agreement shown in fig. (7). composition for theoretical and experimental reaches 0.45 and 0.48 biodiesel, respectively after 120 min. fig. 8, mole fraction of oleic acid and its biodiesel esterification of free fatty acid with high chain alcohol for biodiesel production using semi-batch reactive distillation 18 ijcpe vol.16 no.4 (dec. 2015) -available online at: www.iasj.net [operating conditions: molar ratio alcohol:acid was1:1, reaction temperature 130°c and concentration of homogeneous catalyst 1wt% (h2so4)] conclusions 1the influence of various parameters reaction was studied and shown that the best conditions for biodiesel production were molar ratio of 1:2, temperature 130°c and catalyst amount of 1wt% which give higher conversion 96.55% after very short time of 10 min reaction. 2reversible reaction not occurs because of continuous removal of water during reaction and shifts it to equilibrium. stochiometeric ratio is enough to give high conversion, since it reach 88.91% at time 2 h while reached 97.68% for ratio 1:2 at the same time and may be obtain higher conversion for low ratio if we use high temperature but cannot rise temperature because sulfuric acid is dangerous and cause crackling when added to mixture therefore we prefer high ratio and low temperature when using sulfuric acid as catalyst. 3the most parameter effect on esterification is molar ratio then temperature while amount of catalyst has very small effect on biodiesel production. nomenclature c: concentration of koh solution, mole/l. mwt.: molecular weight of koh, g/mole. v: volume of koh solution, ml. m: weight of sample, g. x: conversion, dimensionless. γ : combinational term for activity coefficient : residual term for activity coefficient references 1graedel, t. e., (2002), "in handbook of green chemistry & technology", clark, j. h., macquarrie, d. j., eds.; blackwell: oxford, pp. 56–61. 2thuijl, e. v. c.j. roos, and l.w.m. beurskens, (2003), "an overview of biofuel technologies", markets and policies in europe (energy research centre of the netherlands). 3sheehan j., v. camobreco, j. duffield, m. graboski, and h. shapouri, (1998), " an overview of biodiesel and petroleum diesel life cycles", national renewable energy laboratory. 4demirbas, a., (2003), " current advances in alternative moto fuel", energy exploration and exploitation, vol. 21, pp. 475–487. 5buczek, b. and l. czepirski, , (2004), "ad oil for production of biodiesel", inform, vol.15, pp. 186–188. 6kiss a.a., a.c. dimian, and g. rothenberg, (2006), "solid acid catalysts for biodiesel production towards sustainable energy", adv. synth. catal., vol. 348, pp. 75-81. 7yan s, s.o. salley, and k.y. simon, (2009), "simultaneous transesterification and esterification of unrefined or waste oils over zno and la2o3 catalysts", appl. catal. a, vol. 353, p. 203. 8shu q, b. yang, h. yuan, s. qing, and g. zhu, (2007), " synthesis of biodiesel from soybean oil and methanol catalyzed by zeolite beta modified with la3 ", catal. comm., vol. 8, pp. 2159-2165. 9jacobson k, r. gopinath, l.c. meher, and a.k. dalai, (2008), "solid acid catalyzed biodiesel production from waste cooking oil", appl catal b: env vol. 85, pp. 8691. wadood t. mohammed and marwa f. abdul jabbar -available online at: www.iasj.net ijcpe vol.16 no.4 (dec. 2015) 19 10furuta s, h. matsuhashi, and k. arata, (2004), "biodiesel fuel production with solid superacid catalysis in fixed bed reactor under atmospheric pressure". catal comm vol. 5, pp. 721-723. 11meher, l. c., d. v. sagar, and s. n. naik, (2006), "technical aspects of biodiesel production by transesterifications", a review. renewable sustainable energy rev., vol. 10, no. 3, p. 248. 12perry r.h. and d. w. green, (1997), "distillation, perry's chemical engineers handbook", 13, 13-83. 13alejski k. and f. duprat. “dynamic simulation of the multicomponent reactive distillation”, (1996), chemical engineering science, vol. 51, no.18, pp. 42374252. 14kusmiyati, and sugiharto a., production of biodiesel from oleic acid and methanol by reactive distillation", (2010), bulletin of chemical reaction engineering & catalysis, vol. 5 , no.1, pp. 1 – 6. 15lotero e, y.j. liu, d.e. lopez, k. suwannakarn, d.a. bruce and j.g. goodwin, (2005), "synthesis of biodiesel via acid catalysis", ind eng chem res, vol. 44, pp. 5353-5363. 16marwa f.a, “production of biodiesel in a reactive distillation catalyzed by different types of catalysts: simulation and experimental tests”, (2015), ph.d thesis, baghdad university. iraqi journal of chemical and petroleum engineering vol.14 no.2 (june 2013) 712 issn: 1997-4884 extraction of oil from eucalyptus camadulensis using water distillation method basma a. abdul-majeed, asrar a. hassan and badoor m. kurji chemical engineering department, college of engineering, university of baghdad-iraq abstract this work was conducted to study the extraction of eucalyptus oil from natural plants (eucalyptus camaldulensis leaves) using water distillation method by clevenger apparatus. the effects of main operating parameters were studied: time to reach equilibrium, temperature (70 to100 ° c), solvent to solid ratio (4:1 to 8:1 (v/w)), agitation speed (0 to 900 rpm), and particle size (0.5 to 2.5 cm) of the fresh leaves, to find the best processing conditions for achieving maximum oil yield. the results showed that the agitation speed of 900 rpm, temperature 100 ° c, with solvent to solid ratio 5:1 (v/w) of particle size 0.5 cm for 160 minute give the highest percentage of oil (46.25 wt.%). the extracted oil was examined by hplc. keyword extraction, water distillation, eucalyptus oil introduction eucalyptus oil c10h18o, is one of the most important essential oil. the oil is extracted from fresh and dried leaves, in addition to branch tips [1]. eucalyptus oil has biological effects, antibacterial, antiviral and antifungal components and long history of use against the effect of cold, influenza, other respiratory infection, rhinitis and sinusitis [2]. essential oils chemistry is very complex; in nature essential oils themselves have many chemical ingredients. some of them play a major part and others a minor part. the ingredients found in essential oils are organic due to their molecular structure which is based on carbon atoms held together by hydrogen atoms. oxygen atoms and sometimes nitrogen and sulphur atoms are also present [3]. they can be essentially classified into two groups: a. volatile fraction: essential oil constituting of 90–95% of the oil in weight. b. nonvolatile residue: this comprises 1–10% of the oil, containing, fatty acids, sterols, carotenoids, waxes, and flavonoids. the properties of eucalyptus oil is shown below [4]: description: colourless to pale yellow liquid with an aromatic and camphoraceous. odour and pungent, cooling, spicy taste. molecular formula: c10h18o. molecular weight: 154. specific gravity at 25℃: 0.920 0.925. refractive index at 20℃: 1.4550 1.4600. optial rotation at 20℃: -0.5° +0.5°. freezing point: 0℃ +1℃. iraqi journal of chemical and petroleum engineering university of baghdad college of engineering extraction of oil from eucalyptus camadulensis using water distillation method 8 ijcpe vol.14 no.2 (june 2013) -available online at: www.iasj.net boiling point at 760 mmhg: 176 177℃. flash point: 49℃. melting point at 760 mmhg: 1.5℃. solubility: slightly soluble in water, soluble in: ethanol, ether, chloroform, and hexane. extraction essential oils can be extracted using a variety of methods, although some are not commonly used today. currently, the most popular method of extraction is steam extraction, but as technological advances are made more efficient and economical methods are being developed. these include methods such as solvent extraction, supercritical fluid extraction, and microwave extraction. the suitability of extraction method varies from plant to plant and there are significant differences in the capital and operational costs associated [5]. principles of distillation it is imperative to note that a liquid always boils at the temperature at which its vapor pressure equals the atmospheric or surrounding pressure. for any two immiscible liquids, the total number of molecules present in the vapor phase is greater than the number which would be present if either pure liquid were present alone at the same temperature. hence, the pressure exerted by the vapor mixture will be greater than that exerted by either pure vapor alone [6]. consequently, the vapor pressure of the whole system increases, that cause to evaporate essential oil at temperature below its boiling point. thus, any essential oil having high boiling point can be evaporated with steam in a ratio such that their combined vapor pressures equal the atmospheric pressure [3]. water distillation in the manufacture of essential oils using the method of water distillation, the botanic material is completely immersed in water and the still is brought to the boil. the main characteristic of this process is that there is direct contact between boiling water and plant material [3]. distillation offers better conditions for the osmosis of oil, because the higher temperature and the movement of water, caused by temperature and pressure fluctuations within the still, accelerate the forces of diffusion to such a point that all the volatile oil contained within the plant tissue can be collected. a special case of water distillation it uses the practice of returning the distillate water to the still after the oil has been separated from it so that it can be re-boiled. the principal behind it is to minimize the losses of oxygenated components. practical advantages of water distillation are that the stills are inexpensive, easy to construct and suitable for field operation. these are still widely used with portable equipment in many countries. this method protects the oils so extracted to a certain degree since the surrounding water acts as a barrier to prevent it from overheating [6]. experimental work fresh leaves of eucalyptus camaldulensis was collected from the gardens of baghdad university, the leaves were taken to laboratory and cut out by a pair of scissors to small part. the schematic diagram of the equipment used is shown in figure 1. the clevenger consists of a main tube combined with condenser and graduated tube with glass stopcock. a return tube for the aqueous part of the distillate connects the bottom of the measuring tube and the main tube. eighty grams of fresh and clean basma a. abdul-majeed, asrar a. hassan and badoor m. kurji -available online at: www.iasj.net ijcpe vol.14 no.2 (june 2013) 9 eucalyptus leaves were placed into the three necked round extraction n flask and soaked with water. clevenger apparatus was linked to the flask as shown in figure 2. the flask was heated using heating mantel. water and leaves, were mixed and allowed to boil. water and extracted eucalyptus oil evaporate. the vapour mixture condensed using reflux condenser, from condenser distillate water and oil flow in to gradated tube; as the oil is not miscible with water it may be easily separated and started accumulating and distillate water returning to the flask, after the oil has been separated from it, so that can be re-boiled. the oil was allowed to stand for sufficient time, to be clear and then it was collected and stored in dark glass vial in a refrigerator until it has been tested. fig. 1, laboratory glassware clevenger fig. 2, photographic representation of water distillation unit results and discussion effect of extraction time the obtained results are plotted in figure 3. the effect of extraction time on oil extraction was studied until the equilibrium was reached, of particle size 0.5 cm at 100°c with solvent (distilled water) to solid ratio 5:1(ml/g) and agitation speed 300 rpm. fig. 3, effect of extraction time on oil extraction by water distillation operating conditions (p.s.=0.5 cm, s.r. =5/1(ml/g), a.s.=300 rpm, t=100°c) the results in figure 3 shows, that extraction of oil increased with time. it is also can be observed that the rate of extraction is fast at the beginning of the extraction but gets slow gradually. the reason is that when the meal is exposed to the fresh solvent, the free oil on the surface of particles gets extracted quickly inducing a fast increase in the extraction rate. furthermore, since the oil concentration is low in the solvent at the beginning of the extraction process, the oil diffuses quickly from the meal to the liquid phase due to the mass transfer effect. as the time passes by, the concentration of oil increases in the solvent resulting in a decrease in the diffusion rate. when the maximum amount of extractable oil is obtained, the oil yield level remains constant even by extending the extraction time; it reaches equilibrium [7]. this results are in agreement with the results which 0 5 10 15 20 25 30 35 40 0 100 200 300 % o il y ie ld time (min.) extraction of oil from eucalyptus camadulensis using water distillation method 10 ijcpe vol.14 no.2 (june 2013) -available online at: www.iasj.net obtained by cassel and vargas (2006) [8]. effect of temperature the obtained results are plotted in figure 4. the effect of extraction temperature was examined in the range of 70 to 100°c under condition of particle size 0.5 cm with solvent to solid ratio 5:1(ml/g) and agitation speed 300 rpm until the equilibrium was reached. at 100°c the liquid boils, as the vapour pressure of liquid equal atmospheric pressure, that cause to ascend the vapour mixture (steam and extractible oil) and yield essential oil .but at temperature below 100°c the vaporized of essential oil with steam cannot occur. fig. 4, effect of temperature on oil extraction by water distillation operating conditions: (p.s. =0.5 cm, s.r. =5/1(ml/g), a.s. =300 rpm) effect of agitation speed the obtained results are plotted in figure 5. the effect of agitation speed was examined in the range of 300 to 900 rpm and compared it with the yield without mixing, under condition of particle size 0.5 cm with solvent to solid ratio 5:1(ml/g) and temperature 100 ◦ c until the equilibrium was reached. fig. 5, effect of agitation speed on oil extraction by water distillation operating condition: (p.s. =0.5 cm, s.r. =5/1(ml/g), temp. =100ºc) as seen in figures 5, the oil yield is increased by increasing the stirring speed and there is obvious difference between the two. figure 3 shows the maximum oil yield without mixing was 27.75 wt.% after 90 minute, but stirring speed of 300 rpm gave yield 37 wt.% after 120 minute and it has reached 46.25 wt.% after 160 minute with stirring speed 900 rpm. from these result the maximum yield of oil by water distillation was 46.25 wt.% after 160 minute with stirring speed 900 rpm. agitation of the solvent is important because it increases the eddy diffusion and therefore increases the transfer of material from the surface of particle to the bulk of the solution [4] [9]. otherwise agglomerations of dense material will settle on the bottom and become thermally degraded [3]. effect of solvent to solid ratio the obtained results are plotted in figure 6. the effect of solvent to solid ratio was examined in the range of 4:1 to 8:1(ml/g), under condition of particle size 0.5 cm with agitation speed 900 rpm and temperature 100°c until the equilibrium was reached. 0 5 10 15 20 25 30 35 40 60 80 100 120 % o il y ie ld temperature,◦c basma a. abdul-majeed, asrar a. hassan and badoor m. kurji -available online at: www.iasj.net ijcpe vol.14 no.2 (june 2013) 11 fig. 6, effect of solvent to solid ratio on oil extraction by water distillation, operating conditions (p.s. = 0.5cm, a.s. = 900rpm, temp. = 100°c) as seen in figure 6, the yield of oil is decreased by increasing the ratio of solvent. the oil yield after 160 minute was 27.75 wt. % at s.r. (8:1), and it has reached 46.25 wt. % at s.r. (5:1). also observed at s.r. (4:1) the oil yield was 37 wt. % after 120 minute. from these result the maximum yield of oil by water distillation was 46.25 wt. % after 160 minute at s.r. (5:1(ml/g)). esters are constituents of essential oils and, in the presence of water, especially at high temperatures, they tend to react with water to form acids and alcohols. if the amount of water is large, the amounts of alcohol and acid will also be large, resulting in a decreased yield of essential oil. and if the amount of water is not enough, as in s.r. (4:1(ml/g)), the plant material may overheat and char [3]. effect of particle size the obtained results are plotted in figure 7. the effect of particle size was examined in three different size (0.5, 1.5, 2.5cm), under condition of solvent to solid ratio 5:1(ml/g) with agitation speed 900 rpm and temperature 100ºc until the equilibrium was reached. as seen in figure 7, less oil is extracted from the larger particles compared to the smaller size particles. the reason is that the smaller the size the greater is the interfacial area between the solid and liquid and therefore the higher is the rate of transfer of material; further, the smaller is the distance the solute must diffuse within the solid as already indicated [11]. therefore, less amount of oil will be transferred from inside the larger particles to the surrounding solution in comparison with the smaller ones [3]. fig. 7, effect of particle size on oil extraction by water distillation operating conditions: (s.r. =5:1, a.s. =900 rpm, temp. =100 ºc) conclusions according to the results obtained from this study, the following conclusions are obtained: 1. the best conditions to yield eucalyptus oil by water distillation method is at 100 ° c with stirring speed 900 rpm for particle size 0.5 cm and solvent to solid ratio 5:1(v/w) for 160 min. 2. the maximum yield of eucalyptus oil produced by water distillation, under best conditions, was about 46.25 wt. %. references 1. najem ali, (2010), "antagonistic activity evaluation of some plants extracts in control of algae and associated organisms" msc. thesis, 20 25 30 35 40 45 50 3 5 7 9 % o il y ie ld sr (ml/g) 0 5 10 15 20 25 30 35 40 45 50 0 100 200 300 % o il y ie ld time,(min.) 0.5 cm 1.5 cm 2.5 cm extraction of oil from eucalyptus camadulensis using water distillation method 12 ijcpe vol.14 no.2 (june 2013) -available online at: www.iasj.net biology department, of the college of science, university of baghdad. 2. a.e. sadlon and d.w.lamson, (2010), "immune-modifying and antimicrobical effects of eucalyptus oil and simple inhalation devices", alternative medicine review, vol.15 (1), pp. 33-47. 3. s. s.handa, s. p.khanuja, g. longo and d. d. rakesh, (2008), "extraction technologies for medicinal and aromatic plants", united nations industrial development organization and the international centre for science and high technology, 260 pages. 4. jiangxi province jishui county hongda natural perfume co.,(2010), " data sheet of eucalyptol". 5. j. kabuba and r. huberts, (2009), " steam extraction of essential oils: investigation of process parameters", the canadian journal of chemical engineering, vol. 87, pp. 915-920. 6. g. ernest, (1948), "the essential oils", dr.van nostrand publishing company, vol.(1), 4 th edition, 427 pages. 7. s.sayyar, z.z.abidin, r.yunus and a.muhammad, (2009), "extraction of oil from jatropha seeds-optimization and kinetics ", american journal of applied sciences, vol. 6(7), pp. 1390-1395. 8. e. cassel and r.vargas, (2006), "experiments and modeling of the cymbopogon winterianus essential oil extraction by steam distillation", j. mex. chem. soc., vol. 50(3), pp.126-129. 9. abdul-nabi mariam, (2011), "extraction of valuable metals from spent hydrodesulfurization catalyst by two stage leaching method", msc. thesis, chemical engineering department, of the college of engineering, university of baghdad. 10. a. mindaryani and s. rahayu, (2007), "essential oil from extraction and steam distillation ocimum basillicum", journal of wcecs, isbn:978-988-98671-6-4. 11. d.k.saxena, s.k.sharma and s.s.sambi, (2011), "comparative extraction of cottonseed oil by nhexane and ethanol", arpn journal of engineering and applied sciences, vol. 6(1), pp. 84-89. abbreviation notation description p.s. particle size. s.r. solvent to solid ratio. a.s. agitation speed. v/w volume / weight. rpm revolution per minute. hplc high pressure liquid chromatography. available online at https://ijcpe.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.19 no.2 (june 2018) 21 – 26 issn: 1997-4884 corresponding authors: faleh h. m. al-mahdawi, email: na, karrar saad, email: karrar.saad11@gmail.com ijcpe is licensed under a creative commons attribution-noncommercial-noderivatives 4.0 international license enhancement of drilling fluid properties using nanoparticles faleh h. m. al-mahdawi and karrar saad petroleum engineering department, unversity of baghdad abstract nanotechnology has shown a lot of promise in the oil and gas sectors, including nanoparticle-based drilling fluids. this paper aims to explore and assess the influence of various nanoparticles on the performance of drilling fluids to make the drilling operation smooth, cost effective and efficient. in order to achieve this aim, we exam the effect of multi wall carbon nanotube and silicon oxide nanoparticles as nanomaterial to prepare drilling fluids samples. anew method for mixing of drilling fluids samples using ultra sonic path principle will be explained. our result was drilling fluids with nano materials have high degree of stability. the results of using multiwall carbon nanotube and silicon oxide show that mwcnt have an effect on rheological properties more than sio2 and good thermal conductivity. also, both nano particles have potential effect on filter loss and stability of mud. the change in density was insignificant which is beneficial for many drilling operations. keywords: drilling fluids properties, multi carbon nanotube, silicon oxide nanoparticles. accepted on 27/2/2017 1introduction different fluids such as drilling, drill-in, and completion used in drilling and production operations. which consider complex systems that contains a multi phases such as fluid phase, a solid phase and a chemical phase. the solids, chemicals and polymers which are used in designing the fluids, will take a major role in functional behavior of the fluids. although there are diverse factors that control the select of fluid base and the mud additives, for a trouble free drilling and economical drilling and production operations, the selection of the additives should take into concern both environmental and technical challenges. the capability of nano technology to be custom made with certain properties will take a major role to defeat the environmental and technical challenges which may occur during drilling and production. it is more likely to encounter new technical challenges in the drilling and production process due to continuous change in the circumstances of drilling such as operational depth, with increasing depth comes subsurface geo-hazards, increasing of horizontal departure to provide maximum production, complication of the drilling operation, shape of wellbore profiles or number of laterals from a motherbore to maximize reservoir contact. also another material related challenge is because the considerable change in chemical, physical and thermal conditions of deeper horizons with more and rougher environmental rules legislates by different governing bodies. so the industry is in continuous searching for chemicals that are physically small, mechanically strong, with stability in the chemical and thermal composition, can be biologically degrade to some level. comparing to other materials, the nanos are the most likable materials of choice for smart fluid design for oil and gas application since it has wide range of variation and high enhanced mechanical, thermal, physio-chemical, electrical, hydrodynamic properties and the possibility to interact of nano materials compared to other materials. thus the nanos are most likely to be the best choice to be used in smart fluid design oil and gas field application. this development in the materials will provide a new class of fluids used in drilling, production and stimulation related applications defined as smart fluids. in oil and gas industry, nano fluids may be defined as any fluid that is used in drilling, drill-in, completion, stimulation processes, etc. that have at least one additive with nanoparticle size in the rangei of 1-100 nanometers. nano expression is given toi particles that havei a dimension that is thousand millionths of a meter. the fluids can be classified as simple and advanced nano-fluids based on the amount of nano-sized additives in the fluid. simple nano-fluids are the fluids with onei nano-sized additive while advanced nanofluids are the fluids with more than ione nano-sized additive. from functional points of view, nano materials could be classified as single functional and multifunctional. multifunctional nano-additives will perform a multi jobs in the fluid systems which will lead into completing the functional tasks of the fluid with high reduction in total solids and/or chemicals content used in the mud which will finally lead to reduction of total fluid cost. one of characteristic features of using nano-based smart fluids is the reduction of overall fluid cost although the individual additives are consider high cost but with remarkable higher functional ability. f. h. m. al-mahdawi and k. saad / iraqi journal of chemical and petroleum engineering91,2 (2018) 21-26 22 the laws that control the nano scale material behavior is totally different from the ones that control the micro and macro scale behavior, this is because of beyond colloidal sizes of nanos with their close proximity to the atomic scale compared to macros and micros. this difference in behavior can be highly noticed in the behavior of carbon nano tubes from those of graphite although both these materials were derived from the graphite mother source [1]. 2drilling fluid properties 2.1. density is one of importance properties in drilling fluids. it is used for controlling the pressure and all calculation of pressure control are done based on the density of the mud column in the hole. baroid mud balance as shown in fig. 1 is used to determine drilling fluid density. the instrument consists of a constant volume cup with a lever arm and rider calibrated to read directly the density of the drilling fluids [2]. fig. 1. mud balance 2.2. rehoelogical properties rheology refers to the deformation and flow behavior of all forms of matter. certain rheological measurements made on fluids, such as apparent viscosity (av), plastic viscosity (pv), gel strength, and yield point (yp) etc. help determine how this fluid will flow under a variety of different conditions. this information is necessary in the design of mud circulating systems required to achieve certain desired goals in drilling operations as its resistance to flow. the required viscosity for a particular drilling fluid operation is influenced by many factors, including mud weight, hole size, pumping rate, rate of drilling, pressure system and requirements, and hold problems. the indicated viscosity as obtained by a rotational viscometer instrument shown in fig. 2 is valid only for that irate of shear and will differ to some degree when measured at a different rate of shear [3]. fig. 2. rotational viscometer 2.3. mud filter loss is the calculation of filtrate passing from the drilling fluid into a porous permeable formation. low fluid losses are a characteristic of excellent drilling fluids and the key to borehole stability. the aim of a good drilling fluid is to create a thin mud cake on the wall of the borehole. this prevents the extra loss of fluids into the formation. the drill pipe may stick to the borehole of the well due to the formation of filter cake or a layer of wet mud solids on the wall of the hole in the formation. the filtrate loss at variety pressures is measured using the filter press tool as shown in fig. (3) [4]. fig. 3. filter press 2.4. thermal conductivity nano fluids are exhibited superior heat transfer properties compared with conventional drilling fluids heat transfer. also, it is known that thermal conductivity of nano fluid is dependent on the volume fraction dimensions and properties of nanoparticles used. by using nanoparticles in heat transfer, the performance of drilling fluid can be significantly improved due to increase surface area to volume ratio [5] . stability of mud is generally generated by its homogeneity after a long aging period. in water base mud, the phase separation is an indicator of mud stability. surface force are more important than gravity force in f. h. m. al-mahdawi and k. saad / iraqi journal of chemical and petroleum engineering91,2 (2018) 21-26 22 controlling colloidal behavior system, this is due to high surface area to volume ratio in nano fluids. zeta meter concept is used to measure the stability on nono fluids by measuring the effect of electrostatic charge between particles. the zeta meter instrument is shown in fig. 4 [6]. fig. 4. zeta meter system 3experimental work and samples preparation the type of drilling fluid that used in this research is ferro chrome lignosulphonate (fcl) which is used in south iraq oil fields. this mud can be preparation in easy way. prehydrated of bentonite fluid should be made first by adding 25 gm sodium bentonite with 400 ml fresh water and mix it at least for 20 min using mixer hamilton beach and let it for 24 hrs for hydration. after that adding 0.15 gm caustic soda to improve the performance of lignosulphonate and rise ph values. 0.15 soda ash is used to treat out calcium ion and to benefaction calcium bentonite. 30 gm of barite is adding to increase mud density. lignosulfonate is used to control rheology and provide filtration control through deflocculating the bentonite in weight of 0.5 gm. after that nano particles of mwcnt and sio2 is added to fluid at laboratory condition in concentration of 0.25, 0.5, 0.75, and 1 gm and mix them for 30 minutes using mixer hamilton beach. after that the fluid is exposed to ultrasonic bath for 30 minutes to ensure good dispersion for nono particles inside fluid as shown in fig. 5. the nanoparticles are added to fluid in small amount, with low concentration (less than 1%). the nanoparticles have the following properties: for multi wall carbon nanotube: a. purity: +95% b. outside diameter: 5-15 nm c. length: 10-20 nm d. form: powders e. color: black for silicon oxide nano particles: a. purity: 99% b. diameter: 10-30 nm c. form: powder d. color: white fig. 5. ultra sonic path 4results of the experimental work 4.1. density results due to importance of mud density, the effects of mwcnt and sio2 nanoparticles were investigated. increase in the mud density by adding nanoparticles is insignificant. by considering fig. 6, density of all nanofluids changes with concentration in the same way. the reason that mwcnt increase mud density more than sio2 is due to the tubular structure of mwcnt like hollow tubes, and their clusters inside mud have the ability of trapping the larger volume of fluid comparison with the cluster of silica nanospheres. thus, mwcnt clusters could reduce volume of the nano fluids, and finally increase its density more than others. fig. 6. effect of nanomaterials concentration on density of drilling mud f. h. m. al-mahdawi and k. saad / iraqi journal of chemical and petroleum engineering91,2 (2018) 21-26 22 4.2. rheological properties the presence of nanomaterials will increase apparent viscosity of the fluid as a result of the interactions between the particles and liquid molecules as shown in fig. 7. fig. 7. apparent viscosity changes with nanomaterials concentration it is obvious from the above figure that mwcnt high viscous than sio2. in some cases, mwcnt are highly entangled, and form a skein inside the fluid when they are dispersed, and it would result in highly viscous behavior in a nanofluid, while the spherical structure of nano silica causes easier movement inside the fluid layers. for the plastic viscosity, which is indicates the resistance to the flow produced be mechanical fraction, the results show no changes in values of pv. fig. 8 shows the change between plastic viscosity and concentration of nano fluid. fig. 8. plastic viscosity changes with nanomaterials concentration for yield point results, generally the yield point of nano fluids is higher than conventional mud. the increase in yield point will provide better suspension of drilling cuttings and efficient cleaning of the wellbore while drilling. the increment of yield point is due to high surface areas per volume and it will increase the interaction of the nanoparticles with the matrix and surrounding base fluid. fig. 9 shows yield point changes with nanoparticles concentration. fig. 9. yield point changes with nanoparticles concentration fig. 10. the effect of nanoparticles on gel strength at different concentrations at 10sec fig. 11. the effect of nanoparticles on gel strength at different concentrations at 10 min f. h. m. al-mahdawi and k. saad / iraqi journal of chemical and petroleum engineering91,2 (2018) 21-26 22 for gel strength, nanofluids show an increasing in gel strength with increasing concentration of nanoparticles. this occurs because of electrostatic force between nanoparticles which cases link together with base fluids to form a rigid structure. fig. 10 and fig. 11 show the effect of nanoparticles on gel strength at different concentrations at 10sec and 10 min respectively. 4.3. mud filter loss results the effect of nano particles on mud measured in terms of fluid loss has been shown in fig. 12. it can be say that the normal drilling fluid will lose its filtrate more than nanomud. this means that the amount of filtrate is decreases slightly with time by increasing the concentration on nanoparticles of mwcnt and sio2, which is result in decreasing of pipe sticking problem. fig. 12. fluid loss for nanomud and normal mud with increase in time from the laboratory observation, the filter cake of nanomud can form an effective lubricating film to reduce pipe sticking inside the wall; this can be shown in fig. 13. it can provide enough reduction of fraction between pipe and borehole also provide easy sliding of the drill string which is good solution for torque and drags problems of horizontal drilling wells. fig. 13. very fine and thin film of mwcnt mud cake 4.4. thermal conductivity results adding polymer materials to drilling fluids would lose their effectiveness at high temperature conditions, which result in operation problems such as barite sag. nanoparticles can be used to improve the ability of thermal conductivity. fig. 14, fig. 15 and fig. 16 show changes in apparent viscosity, plastic viscosity and yield point of the nano fluids with concentration at different temperatures. fig. 14. changes in apparent viscosity of drilling fluids with the temperature at concentration of 1 gm nanoparticles fig. 15. changes in plastic viscosity of drilling fluids with the temperature at concentration of 1 gm nanoparticles fig. 16. changes in yield point of drilling fluids with the temperature at concentration of 1 gm nanoparticles f. h. m. al-mahdawi and k. saad / iraqi journal of chemical and petroleum engineering91,2 (2018) 21-26 22 5conclusion 1due to the amount of nano-particles required for any application is too low (typically˂1%) which reduces the total cost to a great extent. 2increasing in density was too low, which means low horsepower to circulate the mud through the well circulation system. 3due to the strong particle-particle interaction, several nanomaterials can act as viscosifiers and filter loss agent because rheology and fluid loss control are two areas basic to drilling fluids that appear to be suited for the application of nanotechnology. 4from zeta potential calculation, we conclude that drilling fluids with nano particles have high degree of stability. 5the thickness of a filter cake is dependent on the fluid loss or leak off into the formation. when using nano fluids, virtually very thin filter cake forms in the wellbore because of permeability reduction at short time and quickly make up of filter cake. 6nano particles can work as toolbox to activate other properties of drilling fluids, such as viscosity, gel strength, filter loss control, and friction reduction. references [1] md. amanullah, and ashraf m. al-tahini, (2009), "nano-technologyits significance in smart fluid development for oil andi gas field application", society of petroleum engineers. [2] jamal nasser, anna jesil, tariq mohiuddini, majid al ruqeshi, geetha devi, shahjahani mohataram, (2013), " experimentali investigation of drilling fluid performance as nanoparticles", world journal of nano science and engineering. [3] max r. annis and martin v. smith, (1974), "drilling fluids technology", exxon copany, 1996. [4] "drilling fluids manual", amoco production company. [5] xuan, y. and li, q., 2000. heat transfer enhancement of nanofluids. international journal of heat and fluid flow, 21(1), pp.58-64. [6] (2010),"zeta meter manual", version 1.4 rev. 1. اص سائل الحفرتأثير مواد اإلضافة النانوية على خو و الزٍ رزوثل ثوىائغ السفش راد االسبط شد رمٌُخ الٌبًى هسزمجل واػذ فٍ لطبع طٌبػخ الٌفظ و الغبصهأظ ثُش هىاد ًبًىَخ هخزلفخ ػلً ادائُخ سىائل السفش لدؼل ػولُبد أذف لششذ و رىضُر رهزح الذساسخ رهالٌبًىٌ. لزظبدَخ. و لىٍ َزن اًدبص الذساسخ, رن اخزجبس ربثُش الىبسثىى األىلخ و هشًخ و هدذَخ هي الٌبزُخ هالسفش اوثش س .خىاطهب هزؼذد الدذساى الٌبًىَخ و اووسُذ السُلُىىى الٌبًىٌ لزسضش ًوبرج سىائل السفش و فسض زح الذساسخ و اَضب هطشَمخ لغشع خلظ ًوبرج السفش ثبسزخذام الوىخبد فىق الظىرُخ لذ لذهذ فٍ رن اسزخذام زح الذساسخ, الٌزبئح اػطذ اسزمشاسَخ ػبلُخ هب فٍ هذح لغشع اخزجبس اسزمشاسَخ الطُي لذ رن ششزطشَمخ خذَ لطُي السفش الزٌ َسزىٌ ػلً هىاد ًبًىَخ. لذساسخ ربثُش الوىاد الٌبًىَخ. الٌزبئح اظهشد ثبى الطُي ferro chrome lignosulfonateرن اسزخذام طُي . ربثُش الوىاد الٌبًىَخ ػلً الىثبفخ وبى للُل ًىػب هب power law and bingham modelsَسله الوىدَل cp 15. همذاس الزغُش ثبللضوخخ الظبهشَخ وبى ثومذاس mwcnt% لل6و sio2 % لل4زُث اسرفؼذ ثومذاس . الزغُش ثبللضوخخ الجالسُزُىُخ وبى للُل خذا او غُش هسسىط هغ sio2لل cp 6.5و ثومذاس mwcntلل ثسست الشىل الىشوٌ الزٌ َأدٌ الً رملُل االززىبن ثُي الدضَئبد. الضَبدح فٍ sio2ثبلٌسجخ لل ًمظبى للُل ib/100 ft 30ًمطخ الخضىع وبًذ ثومذاس 2 ib/100 ft 15و ثمذاس mwcntثبلٌسجخ لل 2 و السجت sio2لل ُي السفش وبى ػبلٍ ثسجت لىي َؼىد الً ًسجخ الؼبلُخ للشذ السطسٍ الً السدن للوىاد الٌبًىَخ. همذاس الزظلت لط الزوبسه الىجُشح للوىاد الٌبًىَخ. الزدبسة اظهشد همذاس رششُر للُل لالطُبى الزٍ رسزىٌ ػلً هىاد ًبًىَخ ثسجت زدوهب الظغُش هوب َؤدٌ الً غلك هسبهبد وسلخ الزششُر ثسشػخ وجُشح. اى وؼىخ الطُي الوزىىًخ ػلً وسلخ ىاص صَزُخ هوب َؼطٍ اًطجبع خُذ لسل هشىلخ اسزؼظبء االًبثُت. االطُبى الزششُر وبًذ سلُمخ خذا و راد خ الزٍ رسزىٌ ػلً هىاد ًبًىَخ اظهشد دسخخ ػبلُخ هي االسزمشاسَخ و السجت َؼىد الً ووُخ الشذ السطسٍ الؼبلُخ الً السدن. https://www.onepetro.org/conference-paper/spe-126102-ms https://www.onepetro.org/conference-paper/spe-126102-ms https://www.onepetro.org/conference-paper/spe-126102-ms https://www.onepetro.org/conference-paper/spe-126102-ms https://file.scirp.org/pdf/wjnse_2013090517240091.pdf https://file.scirp.org/pdf/wjnse_2013090517240091.pdf https://file.scirp.org/pdf/wjnse_2013090517240091.pdf https://file.scirp.org/pdf/wjnse_2013090517240091.pdf https://file.scirp.org/pdf/wjnse_2013090517240091.pdf https://www.sciencedirect.com/science/article/pii/s0142727x99000673 https://www.sciencedirect.com/science/article/pii/s0142727x99000673 https://www.sciencedirect.com/science/article/pii/s0142727x99000673 available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.23 no.2 (june 2022) 19 – 25 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: sama m. al-jubouri , email: sama.al-jubouri@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. a comparison study for the performance of polyethersulfone ultrafiltration mixed matrix membranes in the removal of heavy metal ions from aqueous solutions haider n. alfalahy and sama m. al-jubouri department of chemical engineering, college of engineering, university of baghdad, aljadria, baghdad, postcode: 10071, iraq, abstract polyethersulfone (pes) ultrafiltration membrane blending nax zeolite crystals as a hydrophilic additive was examined for zinc (ii) and lead ions pb (ii) removal from aqueous solutions. the effect of nax zeolite content on the permeation flux and removal efficiency was studied. the results showed that adding zeolite to the polymer matrix enhanced the permeation flux. the permeation flux of all the zeolite/pes matrix membranes was higher than the pristine membrane. no significant improvement was observed in the removal of zn (ii) ions using all prepared membranes as the removal percentage did not raise above 29.2%. however, the removal percentage of pb (ii) ions was enhanced to 97% using a membrane containing 0.9%wt. zeolite. also, it was found that this membrane has a higher ion exchange capacity than the other prepared membranes. two isotherm models (langmuir model, and freundlich model) were employed in the analysis of the ion exchange equilibrium data. the experimental data best fitted the langmuir model with r2 of 0.889 than the freundlich model. keywords: mixed matrix membranes; nax zeolite; lead ions; zinc ions; ultrafiltration; ion exchange capacity received on 22/03/2022, accepted on 03/05/2022, published on 30/06/2022 https://doi.org/10.31699/ijcpe.2022.2.3 1introduction water is one of the most important natural resources on the earth. it has been found that one of the main reasons for water pollution are human and industrial activities such as metal plating, mining activities, fertilizer industries, etc. which create potential sources of toxic heavy metal ions in the aquatic environment [1], [2]. zn (ii) and pb (ii) are among the toxic heavy metals found in industrial wastewater [3]. zn (ii) can cause irritability, muscle stiffness, loss of appetite, and nausea, while pb (ii) causes anemia, permanent brain damage, kidney dysfunction, and different symptoms related to the nervous system. therefore, it’s necessary to treat industrial wastewater from these toxic metals before discharging into ecosystems [4], [5]. chemical precipitation and coagulation–flocculation have been widely utilized to treat industrial wastewater. however, the main drawbacks associated with applying these techniques are sludge production, the unfeasibility of direct reusing heavy metals, and the consumption of excessive chemicals [6]. other treatment methods such as adsorption and ion exchange are inexpensive and effective for treating the contaminated effluents containing only low concentrations of contaminants [7], [8], [9]. using membrane techniques for environmental protection has several advantages, including eliminating the need for chemical materials, reducing energy consumption, continuous separation mode, separation at moderate environmental conditions, operating in hybrid processes (easily connected to other unit processes), and working as a modular system (possibility of rising the capacity) [10]. the main factors controlling the flow rate and the heavy metal removal efficiency across a membrane are the characteristics of the membrane, such as the porosity, pore size, pore size distribution, surface charge, membrane thickness, degree of membrane hydrophilicity, and presence of functional groups that assist the separation process and solution flow [11], [12]. polyethersulfone (pes) has beneficial properties, including high chemical, mechanical, thermal, and hydraulic stability, good processing, acceptable heat aging resistance, and film-forming characteristics make it an excellent polymer for the synthesis of uf membrane [13]. however, one of the main drawbacks of the pes ultrafiltration membrane in water treatment is membrane fouling, which can reduce the water flux either permanently or temporarily [14]. fouling occurs when pollutants deposite on the surface of a membrane or inside the pores of a membrane, resulting in decrease the efficiency of the membrane. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:sama.al-jubouri@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2022.2.3 h. n. alfalahy and s. m. al-jubouri / iraqi journal of chemical and petroleum engineering 23,2 (2022) 19 25 20 the pes ultrafiltration membrane is used in wastewater to eliminate prevalent and harmful water matters, such as colloids, pathogens, proteins, and viruses but it is less able to remove heavy metal ions [15], [16]. zeolites have demonstrated their ability to improve membranes' water flux, permeability, and antifouling properties, as reported in several studies [17]–[19]. this study identified the need to develop a pes ultrafiltration membrane through fabrication of mmm’s by adding zeolite fillers to the casting solution of a pes uf membrane. the resultant membrane holds the favorable properties of nanofiltration membranes in the removal of heavy metal ions such as providing higher separation efficiency and antifouling performance. besides, they hold some preferable properties of ultrafiltration membranes such as consuming less energy due to operation at low pressure, and thus low operation cost. the equations and models that were used to conduct this work consist of the equations that were used to collect the data including the permeate flux, ion exchange capacity, and the ions rejection; and the equations presenting the results of isotherms including the langmuir and freundlich isotherm models. the permeate flux (j) was calculated using equation 1 [20]: j = v a×t (1) where: j and v are the permeate flux (l/m2. h) and the volume of permeate (l), respectively. a and t are the effective area of membrane (m2) and the run time (h). the remaining concentration of heavy metal ions in permeate was determined by atomic absorption spectroscopy analysis. this analysis was conducted using atomic absorption spectrometer device (model: usa 5000). the metal ions rejection (%r) was calculated using equation 2 [21]: %r = (1 − cp cf ) × 100 (2) the ion exchange capacity results were calculated using equation 3 [22]: qe= (c° − ce) × v w (3) where: qe (mg/g) is the amount of pb (ii) ion removed per a unit mass of ion-exchange membrane, v (l) is the solution volume, w (g) is the weight of membrane, c° (mg/l) and ce (mg/l) are the concentrations of pb (ii) ions at t = 0 and t = equilibrium time (min), respectively. the langmuir and freundlich isotherm models were used to elucidate the ion-exchange behavior of the studied membranes. the correlation factor (r2) was used to assess the validity of the model with respect to the experimental data. the maximum value of r2 indicates a better fit of the model to the experimental data [22]. the langmuir isotherm model describes capturing of pb (ii) ions as by monolayer sites at a homogenous surface. this model is expressed using equation 4 [22], [23]: ce qe = 1 kl qmax + ce qmax (4) where: qe (mg/g) is the amount of pb (ii) ion removed per a unit mass of ion-exchanger membrane ce (mg/l) is the equilibrium concentration of pb (ii) ions, qmax (mg/g) is the langmuir constant and it is a maximum ion exchange capacity of pb (ii) ions, kl (l/mg) is a langmuir constant relating to the free energy of ion-exchange corresponds to the affinity among the pb (ii) ion and membrane surface [22]. the freundlich isothermal model describes capturing of pb (ii) as an ionic exchange by multilayer sites at a heterogeneous surface. this model is expressed in a linearized form using equation 5 [22], [24]: lnqe = ln kf + 1 n ln ce (5) where: kf (mg/g) represents the freundlich constant denoting the ion exchange capacity, and 1/n (unitless) represents the freundlich constant denoting the intensity of the reaction and energy heterogeneity. a larger value of kf indicates good ion exchange efficiency for the m3 membrane, whereas if the value of 1/n is less than 1, it represents a favorable ion exchange [22], [25]. 2experimental 2.1. experimental procedure of uf separation the compositions of the used membranes in this study are mentioned in table 1. the synthesis procedures of these membranes, characterization methods and their results were reported in [26]. table 1. the compositions of the used membranes membrane sample code n, n-dimethyl formamide (dmf) (%wt.) pes (%wt.) zeolite (%wt.) m0 80 20 0 m1 79.7 20 0.3 m2 79.7 20 0.6 m3 79.1 20 0.9 m4 78.8 20 1.2 the performance of the membranes was examined by a crossflow uf system in which the feed stream flow tangentially to the membrane surface. the effective area of each flat sheet membrane piece was 16.24 cm2. all uf experiments were conducted at an operating pressure of 1.6 bar and feed flow rate of 0.75 l/min. the efficiency of the prepared membranes to obtain high flux was studied using using zn (ii) and pb (ii) ions solutions. the results of permeate flux were compared with the flux of a pristine membrane (pes) and matrix membranes (zeolite/pes). the efficiency of the prepared membranes to obtain the highest rejection percentage of heavy metal ions with good flux was studied using zn (ii) and pb (ii) ions solutions. each membrane sample was precompacted for at least 45 min until the flux stabilized at 1.6 bar. h. n. alfalahy and s. m. al-jubouri / iraqi journal of chemical and petroleum engineering 23,2 (2022) 19 25 21 then, the filtration experiments were conducted at steady pressure of 1.6 bar and a feed flow rate of 0.75 l/min. the readings of permeate flux were taken at intervals of 15, 30, 45, 60, 90, and 120 min. the effect of changing nax zeolite concentrations on the ion exchange capacity of zeolite embedded in the prepared mmm’s to remove pb (ii) ions was studied at the equilibrium time. the ion exchange isotherms were examined using m3 membrane for the experiments performed at different initial pb (ii) concentrations of 50, 100, 150, and 200 ppm. 3results and discussion 3.1. effect of nax zeolite content on the permeation flux fig. 1 and fig. 2 show the results of permeate flux for a pristine pes membrane and mmm’s using 50 ppm of zn (ii) and pb (ii) solutions at different times. figure 1 shows that permeate flux of zn (ii) solution significantly improved by zeolite/pes membranes. it can be seen that the permeate flux of pristine pes membrane was 6 l/m2.h and increased to 180, 138, 44, and 61 l/m2.h for m1, m2, m3, and m4, respectively. however, the water flux of m3 and m4 was less than m1 and m2. as early mentioned, this can be attributed to the reduction in porosity of the membrane with increasing nax zeolite content. the same behavior of mmm’s was obtained when they were applied for pb (ii) ions in the uf (see fig. 2). also, fig. 1 and fig. 2 show that the permeate flux slightly decreased with increasing the operation time for mmm’s. this decline in the permeate flux can be attributed to increase the aggregations of heavy metals on the membrane surface (cake-layer) leading to blocking the membrane pores. this layer caused shrinkage in the pore size that leads to decreasing the permeate flux. the same behavior was obtained by abdullah, (2021), [13]. 0 20 40 60 80 100 120 0 50 100 150 200 p e rm e a te f lu x , l m h time (min) m0 m1 m2 m3 m4 fig. 1. the effect of nax zeolite loading on the permeate flux, (experimental conditions: zn (ii) ions concentration 50 ppm, transmembrane pressure of 1.6 bar) 0 20 40 60 80 100 120 0 100 200 300 400 500 p e rm e a te f lu x , l m h time (min) m0 m1 m2 m3 m4 fig. 2. the effect of nax zeolite loading on permeate flux, (experimental conditions: pb (ii) ions concentration 50 ppm, transmembrane pressure of 1.6 bar) 3.2. effect of nax zeolite content on the zinc (ii) and lead (ii) removal fig. 3 and fig. 4 show the effect of the nax zeolite loadings in the casting solution of pes-based membrane on the zn (ii) and pb (ii) ions rejection from solutions containing 50 ppm of zn (ii) and pb (ii) ions. figure 3 shows obtaining of low rejection of zn (ii) ions. the rejection did not exceed 30% for all the prepared membranes. on the contrary, figure 4 shows obtaining of higher rejection of pb (ii) ions. as it is known that the separation process is affected by the exchange with sodium ions at the active sites within the matrix membrane and by the sieving process which depends on the ionic radius relative to pore size. the ionic radius of pb (ii) ion (119 pm) is larger than the ionic radius of zn (ii) ion (74 pm). this means that zn (ii) ion has larger hydration radius than pb (ii) ion, therefore, zn (ii) cations possessed more tendency than pb (ii) cations to adhere with water molecules and pass through the membrane pores together with water molecules in the permeate. consequently, pb (ii) ions rejection was higher than zn (ii) ions rejection. similar behavior was obtained by hadi et. al, (2020) and yurekli, (2016), [12], [29]. fig. 4 shows that the highest rejection of pb (ii) ions was 97% by m3 membrane containing 0.9 %wt. zeolite and it was selected to conduct the next studies. this result can be attributed to the uniform distribution of nax zeolite crystals which provides selective voids (active sites) for capturing pb (ii) ions. however, increasing nax zeolite above 0.9 %wt. reduced the rejection of pb (ii). this is due to agglomeration of zeolite crystals which resulted in nonhomogenous distribution within the matrix membrane which in turn led to the generation of non-selective voids between nanoparticles and the polymer. therefore, the water flux increased but the rejection of pb (ii) ions decreased. this behavior is in agreement with sadiq et. al, (2020), [30]. h. n. alfalahy and s. m. al-jubouri / iraqi journal of chemical and petroleum engineering 23,2 (2022) 19 25 22 according to the uf results obtained using the prepared mmms’ above, the ion-exchange capacity of the zeolite incorporated in the prepared mmms’ will be examined by conducting ion-exchange experiments for pb (ii) ions solutions. m0 m1 m2 m3 m4 0 20 40 60 80 100 zn (i i) io ns re jrc tio n (% ) membrane code 19.6% 21% 28% 20% 29.2% fig. 3. effect of nax zeolite content on zn (ii) ions rejection, (experimental conditions: zn (ii) ions concentration of 50 ppm, transmembrane pressure of 1.6 bar) m0 m1 m2 m3 m4 0 20 40 60 80 100 97% 57.4% 45.2%46% p b (ii ) i on s re je ct io n (% ) membrane code 61.2% fig. 4. effect of nax zeolite content on pb (ii) ions rejection, (experimental conditions: pb (ii) ions concentration of 50 ppm, transmembrane pressure of 1.6 bar) 3.3. ion exchange capacity the ion exchange capacity of mmm’s increased with increase the number of active sites within the matrix membrane. figure 5 shows that the ion exchange capacity increased with increasing the content of nax zeolite added to the casting solution. the value of ion exchange capacity was 1380 mg/g for m1 and increased to 1937.1 mg/g for m2. while, the maximum value of ion exchange capacity (3637.5 mg/g) was obtained for m3. the ion exchange capacity increased due to increasing the concentration of nax zeolite added to the casting solution forming membranes with more available active sites for capturing of pb (ii) ions [31]. however, the ion exchange capacity decreased when the concentration of nax zeolite increased to 1.2 %wt. which is possibly due to agglomeration of crystals that reduced the active sites within a membrane. the same behavior was observed by zhang et. al, (2018), [32]. m1 m2 m3 m4 1000 1500 2000 2500 3000 3500 4000 q e ( m g /g ) membrane code fig. 5. the ion exchange capacity of the membranes used for pb (ii) ions removal, (experimental conditions: pb (ii) ions concentration of 50 ppm, ph of 6, feed temperature of 25 °c, transmembrane pressure of 1.6 bar) 3.4. ion exchange isotherm fig. 6 (a) and (b) show the plots of the langmuir isotherm model and freundlich isotherm model. the correlation factor (r2) of langmuir and freundlich isotherms are presented in table 2. it can be seen that the removal of pb (ii) ions by m3 is best fitted with the langmuir isotherm model (r2 value of 0.8809) in comparison with freundlich isotherm model with r2 = 0.4798. this result indicates occurring of homogeneous ion exchange (monolayer sites) on the zeolite crystals occupying the upper surface of the ion exchanger membrane. these results conflict with the results obtained by zeolite/carbon used for heavy metals removal [25]. referring to this previous study, the freundlich isotherm model successfully agreed with the experimental data of manganese (ii) ion removal by the ion-exchange process and was more fitted than the langmuir isotherm model. the obtained results can be attributed to as difference in the surface properties of the ion exchanger material. in the current study, pes support was incorporated with zeolite, whereas in the abovementioned previous work, the support was not used in the removal process. therefore, in the current study, pes has an effect in the removal process as a result of the electrostatic attraction force besides the zeolite which favors the monolayer sites uptake on the upper layer of the m3 membrane. the langmuir constant kl and the maximum ion exchange capacity qmax were calculated from the slope (see figure 6 .a) and presented in table 2. the langmuir monolayer ion exchange capacity (qmax) was 10000 mg/g, the langmuir equilibrium constant, (kl) was 0.0555 l/mg. regarding the magnitude of freundlich constants, kf (ion exchange capacity) and 1/n (reaction intensity) were estimated from the slop (see fig. 6 .b and table 2). kf and 1/n were 4451.961 mg/g and 0.0914 respectively. h. n. alfalahy and s. m. al-jubouri / iraqi journal of chemical and petroleum engineering 23,2 (2022) 19 25 23 table 2. isotherm parameters for the pb (ii) ions removal by m3 membrane langmuir l (mg/g) k maxmetal ion q 2(l/mg) r freundlich 2(mg/g) 1/n rf k pb (ii) 10000 0.0555 0.8809 4451.961 0.0914 0.4798 0 20 40 60 80 100 120 0.000 0.004 0.008 0.012 0.016 0 1 2 3 4 5 8.4 8.6 8.8 9.0 9.2 r 2 = 0.4798 (b) c e / q e , g ce, mg (a) r 2 = 0.8809 ln q e ln ce fig. 6. a) plots of the langmuir model b) plots of the freundlich isotherm model. (m3, ph of 6, and tmp of 1.6 bar) 4conclusions in conclusion, the permeation flux of all matrix membranes (i.e., m1, m2, m3, and m4) was higher than that of the pristine pes membrane (m0). the highest rejection of pb (ii) ions was 97% by adding 0.9 %wt. of nax zeolite for m3 membrane. however, the results showed all prepared membranes gave the same efficiency for zn (ii) ions removal. the maximum value of ion exchange capacity was of 3637.5 mg/g for the modifiedmembrane with 0.9 %wt. of nax zeolite. langmuir isotherm model is the best-fitted model compared with freundlich isotherm model for describing the data of pb (ii) ions removal by m3 membrane. references [1] fu, f. & wang, q. ‘removal of heavy metal ions from wastewaters: a review’, journal of environmental management, 92(3), pp. 407–418 (2011). [2] karadede, h. and ünlü, e. ‘concentrations of some heavy metals in water, sediment and fish species from the ataturk dam lake (euphrates), turkey’, chemosphere, 41(9), pp. 1371–1376 (2000). [3] rahman, m. l., wong, z. j., sarjadi, m. s., soloi, s., arshad, s. e., bidin, k. & musta, b. ‘heavy metals removal from electroplating wastewater by waste fiber-based poly(amidoxime) ligand’, water, 13(9), pp. 1–20 (2021). [4] lesmana, s.o., febriana, n., soetaredjo, f.e., sunarso, j. and ismadji, s. studies on potential applications of biomass for the separation of heavy metals from water and wastewater. biochemical engineering journal, 44(1), pp.19-41 (2009). [5] obasi, p. n. & akudinobi, b. b. ‘potential health risk and levels of heavy metals in water resources of lead– zinc mining communities of abakaliki, southeast nigeria’, applied water science, 10(7) (2020). [6] algureiri, a.h. and abdulmajeed, y.r. removal of ni (ii), pb (ii), and cu (ii) from industrial wastewater by using nf membrane. iraqi journal of chemical and petroleum engineering, 18(1), pp.87-98 (2017). [7] mohammed, a.a. biosorption of lead, cadmium, and zinc onto sunflower shell: equilibrium, kinetic, and thermodynamic studies. iraqi journal of chemical and petroleum engineering, 16(1), pp.91-105 (2015). [8] hussein, t.k. comparative study for removal of zn+2 ions from aqueous solutions by adsorption and forward osmosis. iraqi journal of chemical and petroleum engineering, 18(2), pp.125-138 (2017). [9] khalid, m.w. and salman, s.d. adsorption of chromium ions on activated carbon produced from cow bones. iraqi journal of chemical and petroleum engineering, 20(2), pp.23-32 (2019). [10] saljoughi, e. & mousavi, s. m. ‘preparation and characterization of novel polysulfone nanofiltration membranes for removal of cadmium from contaminated water’, separation and purification technology, 90, pp. 22–30 (2012). [11] abdullah, n., yusof, n., lau, w. j., jaafar, j. & ismail, a. f. ‘recent trends of heavy metal removal from water/wastewater by membrane technologies’, journal of industrial and engineering chemistry, 76, pp. 17–38 (2019). [12] hadi, s., mohammed, a. a., al-jubouri, s. m., abd, m. f., majdi, h. s., alsalhy, q. f., rashid, k. t., ibrahim, s. s., salih, i.k. & figoli, a. ‘experimental and theoretical analysis of lead pb2+ and cd2+ retention from a single salt using a hollow fiber pes membrane’, membranes, 10(7), p. 136 (2020). [13] abdullah, m. h. ‘implementation of hierarchically porous zeolite composites for chromium ions removal’, msc. thesis, college of engineering baghdad university (2021). [14] kadhim, r. j., al-ani, f. h., al-shaeli, m., alsalhy, q. f. & figoli, a. ‘removal of dyes using graphene oxide (go) mixed matrix membranes’, membranes, 10(12), pp. 1–24 (2020). [15] warsinger, d. m., chakraborty, s., tow, e. w., plumlee, m. h., bellona, c., loutatidou, s., karimi, l., mikelonis, a. m., achilli, a., ghassemi, a., padhye, l. p., snyder, s. a., curcio, s., vecitis, c. d., arafat, h. a. & lienhard v, j. h. ‘a review of polymeric membranes and processes for potable water reuse’, progress in polymer science, 81, pp. 209–237 (2018). [16] gao, j., qiu, y., hou, b., zhang, q. & zhang, x. ‘treatment of wastewater containing nickel by complexationultrafiltration using sodium polyacrylate and the stability of paa-ni complex in the shear field’, chemical engineering journal, 334(november 2017), pp. 1878–1885 (2018). https://www.sciencedirect.com/science/article/pii/s0301479710004147 https://www.sciencedirect.com/science/article/pii/s0301479710004147 https://www.sciencedirect.com/science/article/pii/s0301479710004147 https://www.sciencedirect.com/science/article/pii/s0301479710004147 https://www.sciencedirect.com/science/article/abs/pii/s0045653599005639 https://www.sciencedirect.com/science/article/abs/pii/s0045653599005639 https://www.sciencedirect.com/science/article/abs/pii/s0045653599005639 https://www.sciencedirect.com/science/article/abs/pii/s0045653599005639 https://www.mdpi.com/2073-4441/13/9/1260 https://www.mdpi.com/2073-4441/13/9/1260 https://www.mdpi.com/2073-4441/13/9/1260 https://www.mdpi.com/2073-4441/13/9/1260 https://www.mdpi.com/2073-4441/13/9/1260 https://www.sciencedirect.com/science/article/abs/pii/s1369703x08004075 https://www.sciencedirect.com/science/article/abs/pii/s1369703x08004075 https://www.sciencedirect.com/science/article/abs/pii/s1369703x08004075 https://www.sciencedirect.com/science/article/abs/pii/s1369703x08004075 https://www.sciencedirect.com/science/article/abs/pii/s1369703x08004075 https://link.springer.com/article/10.1007/s13201-020-01233-z??utm_source=other_website&error=cookies_not_supported&code=903c77a4-f6ff-4dd6-9af0-dc8d50fcc811 https://link.springer.com/article/10.1007/s13201-020-01233-z??utm_source=other_website&error=cookies_not_supported&code=903c77a4-f6ff-4dd6-9af0-dc8d50fcc811 https://link.springer.com/article/10.1007/s13201-020-01233-z??utm_source=other_website&error=cookies_not_supported&code=903c77a4-f6ff-4dd6-9af0-dc8d50fcc811 https://link.springer.com/article/10.1007/s13201-020-01233-z??utm_source=other_website&error=cookies_not_supported&code=903c77a4-f6ff-4dd6-9af0-dc8d50fcc811 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/195 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/195 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/195 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/195 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/248 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/248 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/248 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/248 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/208 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/208 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/208 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/208 https://doi.org/10.31699/ijcpe.2019.2.4 https://doi.org/10.31699/ijcpe.2019.2.4 https://doi.org/10.31699/ijcpe.2019.2.4 https://doi.org/10.31699/ijcpe.2019.2.4 https://www.sciencedirect.com/science/article/abs/pii/s1383586612000950 https://www.sciencedirect.com/science/article/abs/pii/s1383586612000950 https://www.sciencedirect.com/science/article/abs/pii/s1383586612000950 https://www.sciencedirect.com/science/article/abs/pii/s1383586612000950 https://www.sciencedirect.com/science/article/abs/pii/s1383586612000950 https://www.sciencedirect.com/science/article/abs/pii/s1226086x19301194 https://www.sciencedirect.com/science/article/abs/pii/s1226086x19301194 https://www.sciencedirect.com/science/article/abs/pii/s1226086x19301194 https://www.sciencedirect.com/science/article/abs/pii/s1226086x19301194 https://www.sciencedirect.com/science/article/abs/pii/s1226086x19301194 https://www.mdpi.com/2077-0375/10/7/136 https://www.mdpi.com/2077-0375/10/7/136 https://www.mdpi.com/2077-0375/10/7/136 https://www.mdpi.com/2077-0375/10/7/136 https://www.mdpi.com/2077-0375/10/7/136 https://www.mdpi.com/2077-0375/10/7/136 https://www.mdpi.com/2077-0375/10/7/136 https://www.mdpi.com/2077-0375/10/12/366 https://www.mdpi.com/2077-0375/10/12/366 https://www.mdpi.com/2077-0375/10/12/366 https://www.mdpi.com/2077-0375/10/12/366 https://www.sciencedirect.com/science/article/pii/s0079670017300102 https://www.sciencedirect.com/science/article/pii/s0079670017300102 https://www.sciencedirect.com/science/article/pii/s0079670017300102 https://www.sciencedirect.com/science/article/pii/s0079670017300102 https://www.sciencedirect.com/science/article/pii/s0079670017300102 https://www.sciencedirect.com/science/article/pii/s0079670017300102 https://www.sciencedirect.com/science/article/pii/s0079670017300102 https://www.sciencedirect.com/science/article/pii/s0079670017300102 https://www.sciencedirect.com/science/article/abs/pii/s1385894717320090 https://www.sciencedirect.com/science/article/abs/pii/s1385894717320090 https://www.sciencedirect.com/science/article/abs/pii/s1385894717320090 https://www.sciencedirect.com/science/article/abs/pii/s1385894717320090 https://www.sciencedirect.com/science/article/abs/pii/s1385894717320090 https://www.sciencedirect.com/science/article/abs/pii/s1385894717320090 h. n. alfalahy and s. m. al-jubouri / iraqi journal of chemical and petroleum engineering 23,2 (2022) 19 25 24 [17] chauke, n. m., moutloali, r. m. and ramontja, j. ‘development of zsm-22/polyethersulfone membrane for effective salt rejection’, polymers, 12(7), pp. 1–15 (2020). [18] wang, b., jackson, e. a., hoff, j. w. & dutta, p. k. ‘fabrication of zeolite/polymer composite membranes in a roller assembly’, microporous and mesoporous materials, 223, pp. 247–253 (2016). [19] liu, c., lee, j., ma, j. & elimelech, m. ‘antifouling thin-film composite membranes by controlled architecture of zwitterionic polymer brush layer’, environmental science and technology, 51(4), pp. 2161–2169 (2017). [20] yi, z., shao, f., yu, l., song, n., dong, h., pang, b., yu, j., feng, j. & dong, l. ‘chemical grafting n-goqd of polyamide reverse osmosis membrane with improved chlorine resistance, water flux and nacl rejection’, desalination, 479, p. 114341 (2020). [21] jun, b. m., cho, j., jang, a., chon, k., westerhoff, p., yoon, y. & rho, h. ‘charge characteristics (surface charge vs. zeta potential) of membrane surfaces to assess the salt rejection behavior of nanofiltration membranes’, separation and purification technology, 247(february), pp. 1-10 (2020). [22] al-jubouri, s. m. and holmes, s. m. ‘hierarchically porous zeolite x composites for manganese ion-exchange and solidification: equilibrium isotherms, kinetic and thermodynamic studies’, chemical engineering journal, 308, pp. 476–491 (2016). [23] kumar, m., shevate, r., hilke, r. & peinemann, k. v. ‘novel adsorptive ultrafiltration membranes derived from polyvinyltetrazole-co-polyacrylonitrile for cu(ii) ions removal’, chemical engineering journal, 301(ii), pp. 306–314 (2016). [24] lee, s. h. & shrestha, s. ‘application of micellar enhanced ultrafiltration (meuf) process for zinc (ii) removal in synthetic wastewater: kinetics and two-parameter isotherm models’, international biodeterioration and biodegradation, 95(pa), pp. 241–250 (2014). [25] almasi, a., omidi, m., khodadadian, m., khamutian, r. & gholivand, m. b. ‘lead(ii) and cadmium(ii) removal from aqueous solution using processed walnut shell: kinetic and equilibrium study’, toxicological and environmental chemistry, 94(4), pp. 660–671 (2012). [26] alfalahy, h. n. & al-jubouri, s. m. “preparation and application of polyethersulfone ultrafiltration membrane incorporating nax zeolite for lead ions removal from aqueous solutions,” desalin. water treat., vol. 248, pp. 149–162, (2022). [27] al-jubouri, s. m., rio, d. d. h. d., alfutimie, a., curry, n. a. & holmes, s. m. ‘understanding the seeding mechanism of hierarchically porous zeolite/carbon composites’, microporous and mesoporous materials, 268(april), pp. 109–116 (2018). [28] al-jubouri, s. m., al-batty, s. i., senthilnathan, s., sihanonth n., sanglura, l., shan, h. & holmes, s. m. ‘utilizing faujasite-type zeolites prepared from waste aluminum foil for competitive ion-exchange to remove heavy metals from simulated wastewater’, desalination and water treatment, 231, pp. 166–181 (2021). [29] yurekli, y. ‘removal of heavy metals in wastewater by using zeolite nano-particles impregnated polysulfone membranes’, journal of hazardous materials, 309, pp. 53–64 (2016). [30] sadiq, a. j., awad, e. s., shabeeb, k. m., khalil, b. i., al-jubouri, s. m., sabirova, t. m., tretyakova, n. a., majdi, h. s., alsalhy, q. f., braihi, a. j. ‘comparative study of embedded functionalised mwcnts and go in ultrafiltration (uf) pvc membrane: interaction mechanisms and performance’, international journal of environmental analytical chemistry, pp. 1–22 (2020). [31] shahrin, s., lau, w. j., goh, p. s., ismail, a. f. & jaafar, j. ‘adsorptive mixed matrix membrane incorporating graphene oxide-manganese ferrite (gmf) hybrid nanomaterial for efficient as (v) ions removal’, composites part b: engineering, 175, p. 107150 (2019). [32] zhang, x., fang, x., li, j., pan, s., sun, x., shen, j., han, w., wang, l. & zhao, s. ‘developing new adsorptive membrane by modification of support layer with iron oxide microspheres for arsenic removal’, journal of colloid and interface science, 514, pp. 760–768 (2018). https://www.mdpi.com/2073-4360/12/7/1446 https://www.mdpi.com/2073-4360/12/7/1446 https://www.mdpi.com/2073-4360/12/7/1446 https://www.mdpi.com/2073-4360/12/7/1446 https://www.sciencedirect.com/science/article/abs/pii/s1387181115006022 https://www.sciencedirect.com/science/article/abs/pii/s1387181115006022 https://www.sciencedirect.com/science/article/abs/pii/s1387181115006022 https://www.sciencedirect.com/science/article/abs/pii/s1387181115006022 https://pubs.acs.org/doi/abs/10.1021/acs.est.6b05992 https://pubs.acs.org/doi/abs/10.1021/acs.est.6b05992 https://pubs.acs.org/doi/abs/10.1021/acs.est.6b05992 https://pubs.acs.org/doi/abs/10.1021/acs.est.6b05992 https://pubs.acs.org/doi/abs/10.1021/acs.est.6b05992 https://www.sciencedirect.com/science/article/abs/pii/s0011916419322684 https://www.sciencedirect.com/science/article/abs/pii/s0011916419322684 https://www.sciencedirect.com/science/article/abs/pii/s0011916419322684 https://www.sciencedirect.com/science/article/abs/pii/s0011916419322684 https://www.sciencedirect.com/science/article/abs/pii/s0011916419322684 https://www.sciencedirect.com/science/article/abs/pii/s0011916419322684 https://www.sciencedirect.com/science/article/abs/pii/s1383586620315008 https://www.sciencedirect.com/science/article/abs/pii/s1383586620315008 https://www.sciencedirect.com/science/article/abs/pii/s1383586620315008 https://www.sciencedirect.com/science/article/abs/pii/s1383586620315008 https://www.sciencedirect.com/science/article/abs/pii/s1383586620315008 https://www.sciencedirect.com/science/article/abs/pii/s1383586620315008 https://www.sciencedirect.com/science/article/abs/pii/s1383586620315008 https://www.sciencedirect.com/science/article/abs/pii/s1385894716313250 https://www.sciencedirect.com/science/article/abs/pii/s1385894716313250 https://www.sciencedirect.com/science/article/abs/pii/s1385894716313250 https://www.sciencedirect.com/science/article/abs/pii/s1385894716313250 https://www.sciencedirect.com/science/article/abs/pii/s1385894716313250 https://www.sciencedirect.com/science/article/abs/pii/s1385894716313250 https://www.sciencedirect.com/science/article/abs/pii/s1385894716306192 https://www.sciencedirect.com/science/article/abs/pii/s1385894716306192 https://www.sciencedirect.com/science/article/abs/pii/s1385894716306192 https://www.sciencedirect.com/science/article/abs/pii/s1385894716306192 https://www.sciencedirect.com/science/article/abs/pii/s1385894716306192 https://www.sciencedirect.com/science/article/abs/pii/s0964830514000754 https://www.sciencedirect.com/science/article/abs/pii/s0964830514000754 https://www.sciencedirect.com/science/article/abs/pii/s0964830514000754 https://www.sciencedirect.com/science/article/abs/pii/s0964830514000754 https://www.sciencedirect.com/science/article/abs/pii/s0964830514000754 https://www.sciencedirect.com/science/article/abs/pii/s0964830514000754 https://www.tandfonline.com/doi/abs/10.1080/02772248.2012.671328 https://www.tandfonline.com/doi/abs/10.1080/02772248.2012.671328 https://www.tandfonline.com/doi/abs/10.1080/02772248.2012.671328 https://www.tandfonline.com/doi/abs/10.1080/02772248.2012.671328 https://www.tandfonline.com/doi/abs/10.1080/02772248.2012.671328 https://www.tandfonline.com/doi/abs/10.1080/02772248.2012.671328 https://www.sciencedirect.com/science/article/abs/pii/s1387181118302026 https://www.sciencedirect.com/science/article/abs/pii/s1387181118302026 https://www.sciencedirect.com/science/article/abs/pii/s1387181118302026 https://www.sciencedirect.com/science/article/abs/pii/s1387181118302026 https://www.sciencedirect.com/science/article/abs/pii/s1387181118302026 https://www.sciencedirect.com/science/article/abs/pii/s1387181118302026 https://www.sciencedirect.com/science/article/abs/pii/s0304389416300644 https://www.sciencedirect.com/science/article/abs/pii/s0304389416300644 https://www.sciencedirect.com/science/article/abs/pii/s0304389416300644 https://www.sciencedirect.com/science/article/abs/pii/s0304389416300644 https://www.tandfonline.com/doi/abs/10.1080/03067319.2020.1858073 https://www.tandfonline.com/doi/abs/10.1080/03067319.2020.1858073 https://www.tandfonline.com/doi/abs/10.1080/03067319.2020.1858073 https://www.tandfonline.com/doi/abs/10.1080/03067319.2020.1858073 https://www.tandfonline.com/doi/abs/10.1080/03067319.2020.1858073 https://www.tandfonline.com/doi/abs/10.1080/03067319.2020.1858073 https://www.tandfonline.com/doi/abs/10.1080/03067319.2020.1858073 https://www.tandfonline.com/doi/abs/10.1080/03067319.2020.1858073 https://www.sciencedirect.com/science/article/abs/pii/s1359836819307243 https://www.sciencedirect.com/science/article/abs/pii/s1359836819307243 https://www.sciencedirect.com/science/article/abs/pii/s1359836819307243 https://www.sciencedirect.com/science/article/abs/pii/s1359836819307243 https://www.sciencedirect.com/science/article/abs/pii/s1359836819307243 https://www.sciencedirect.com/science/article/abs/pii/s1359836819307243 https://www.sciencedirect.com/science/article/abs/pii/s002197971830002x https://www.sciencedirect.com/science/article/abs/pii/s002197971830002x https://www.sciencedirect.com/science/article/abs/pii/s002197971830002x https://www.sciencedirect.com/science/article/abs/pii/s002197971830002x https://www.sciencedirect.com/science/article/abs/pii/s002197971830002x https://www.sciencedirect.com/science/article/abs/pii/s002197971830002x h. n. alfalahy and s. m. al-jubouri / iraqi journal of chemical and petroleum engineering 23,2 (2022) 19 25 25 المصفوفة المختلطة للترشيح الفائق من البولي إيثير سلفون دراسة مقارنة إلداء أغشية في إزالة أيونات المعادن الثقيلة من المحاليل المائية حيدر نزار عبد االمير و سما محمد عبد للا جامعة بغداد, كلية الهندسة, قسم الهندسة الكيمياوية الخالصة الفائق الترشيح غشاء فحص زيواليت pesتم بلورات مع مزجه تم إلزالة naxالذي للماء محبة كمادة ( ) iiأيونات الزنك تأثير محتوى الزيواليت ii( والرصاص تدفق nax( من المحاليل المائية. تمت دراسة على ان تدفق النفاذية وكفاءة اإلزالة. أظهرت النتائج أن إضافة الزيواليت إلى مصفوفة البوليمر عزز تدفق النفاذية. ك زيواليت مصفوفة أغشية لجميع زيواليت pes -النفاذية من الخالي الغشاء من أي naxأعلى يالحظ لم . ( لم ترتف فوق ( بٳستخدام جميع األغشية المعدةiiتحسن كبير في إزالة أيونات الزنك حيث أن نسبة اإلزالة 29.2 ( الرصاص أيونات إزالة نسبة تحسين تم ذلك, مع . %ii إلى على 97 ( يحتوي غشاء بٳستخدام % األخرى 0.9 األغشية من أعلى أيوني تبادل قدرة لديه الغشاء هذا أن وجد كذلك، الزيواليت. من بالوزن % التبادل توازن بيانات تحليل في فروندليش( ونموذج النجمير )نموذج ايزوثيرم نموذجين استخدام تم المعدة. من نموذج فروندليش. 0.889عند 2rنموذج النجمير بشكل أفضل مع األيوني. تالئم البيانات التجريبية , أيونات الرصاص, أيونات الزنك, الترشيح الفائق, سعة التبادل االيوني. naxالكلمات الدالة: أغشية مصفوفة مختلطة, زيواليت available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.23 no.4 (december 2022) 17 – 24 eissn: 2618-0707, pissn: 1997-4884 corresponding author: name: ohood salman, email: ohoodthaar@gmail.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. permeability prediction in one of iraqi carbonate reservoir using statistical, hydraulic flow units, and ann methods ohood salmana, omar al-fatlawia,b, and sameer al-jawadc a department of petroleum engineering, college of engineering, university of baghdad, baghdad, iraq b wasm: energy and chemical engineering, curtin university, wa, australia c ministry of oil/rfd, baghdad, iraq abstract permeability is an essential parameter in reservoir characterization because it is determined hydrocarbon flow patterns and volume, for this reason, the need for accurate and inexpensive methods for predicting permeability is important. predictive models of permeability become more attractive as a result. a mishrif reservoir in iraq's southeast has been chosen, and the study is based on data from four wells that penetrate the mishrif formation. this study discusses some methods for predicting permeability. the conventional method of developing a link between permeability and porosity is one of the strategies. the second technique uses flow units and a flow zone indicator (fzi) to predict the permeability of a rock mass using data from cores and well logs. the approach is used to predict the permeability of some uncored wells/intervals. the flow zone indicator is an efficient metric for calculating hydraulic flow units since it is based on the geological properties of the material and varied geometries pore of rock mass (hfu) and artificial neural network (ann) analysis is another way for predicting permeability. the result shows the fzi method, gave acceptable results compared with the obtained from core analysis than the other methods. keywords: permeability, fzi, artificial neural network, mishrif formation. received on 06/06/2022, accepted on 10/09/2022, published on 30/12/2022 https://doi.org/10.31699/ijcpe.2022.4.3 1introduction reservoir characterization approaches are important to provide a better indication of the flow capabilities and storage of petroleum reservoirs [1], especially for heterogeneous carbonate reservoirs [2]. permeability which reflects the rock's capacity to transmit fluids (oil, gas, and water) through pore spaces, is one of the essential properties of reservoir rocks. laboratory core analysis can get permeability data on (1.5) in core plugs and sidewall core. however, permeability prediction in uncored sections is crucial because most wells do not core because of challenges during coring and more significant expenses [3]-[5]. one of the essential properties of a petroleum deposit is its permeability. permeability can be assessed in the laboratory or the field by using core samples or other well-test information [6]. you need to know how permeable the rock is to write an effective reservoir description [7]. because permeability is recognized as a fundamental quantity that influences reservoir management, well completion, and production methods, it's vital to get it right [8]. flow zone indicators (fzis), one of the most used approaches for permeability prediction, identify flow units (groups of rocks) whose elements have particular flow characteristics that are different from those of other units in the rock volume [9]. artificial neural network (ann) which is the most often used since it does not require any correlations between variables, and neural networks offers a flexible technique to generalize linear regression [10], [11]. three different methods are used in to estimate permeability flow zone indicator and classical approaches rely on relationship between porosity permeability, and an artificial neural network (ann) is using traditional well log and core data to predict permeability [12]. the approach is demonstrated by applying it to one of iraq's oil fields. four wells were chosen from field as located at east south of iraq (xx 1, xx 2, xx 3, xx 4) because they were evenly distributed across the mishrif formation to assess the reservoir's properties and rock type. the field is one of iraq's most important oil fields in the southeast. seismic tests undertaken between 1973 and 1988 discovered the field in the dhi qar city. the field is 34 kilometres long and 17 kilometres wide, implying the presence of unfaulted underlying fold structure with a general northwest – southeast trend [13]. the shallowest of iraq's x field's hydrocarbon-bearing formations is the mishrif reservoir. fine to coarse bioclastic limestones exhibit a shallow depositional domain, the average http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:ohoodthaar@gmail.com http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2022.4.3 o. salman et al. / iraqi journal of chemical and petroleum engineering 23,4 (2022) 17 24 18 thickness of this formation is about 170 m. mishrif formation consists of two parts: upper part (ma) unit and lower mishrif (mb) separated by shale. the lower part also subdivided into two reservoir subunits (mb1 and mb2) [14]. 2methodology 2.1. classical method the permeability-porosity relationship is found through core analysis and turned into well-log data. using the equation below, log-derived porosity in uncored wells or zones is used to figure out empirical permeability [15], [16]. 𝐾 = 𝑎 ∗ 𝑒𝑥𝑝(𝑏𝜙) (1) where: k: is the permeability (md), ϕ: is the porosity (fraction), and, a and b: are the constants to be fitted to the case study. the link between porosity and permeability was determined from core for mb1 and mb2 units from four of the wells studied; however, in some cases, the association between core analysis results and porosity and permeability is low because of the heterogeneity of rocks as shown in fig. 1 and fig. 2. in the same reservoir, can exits both high and low permeability zone with same porosity values. that requires accurate alternative methods to predict permeability in uncored intervals. fig. 1. permeability vs porosity cross plot for mb1 unit fig. 2. permeability vs porosity cross plot for mb2 unit the results of the correlation between permeability porosity of mishrif formation obtained from core analysis are shown in table 1. table 1. classical permeability formulas unit name formula number of core samples (n) (r2) mb1 for all wells k = 0.0129*exp(28.9996*ø) 201 0.368 mb2 for all wells k = 0.0799*exp(17.64*ø) 87 0.3062 2.2. flow zone indicator this technique is advised for determining the permeability of the reservoir. based on the hydraulic flow units, core data was categorised by the slope of the linear fitted line between porosity and permeability. this revealed that geological conditions corresponded to each other [16], [17]. the equation is simplified if permeability and porosity are measured in millidarcy and fraction, respectively [18]. 𝑅𝑄𝐼 = 0.0314 ∗ √𝐾 ∅e⁄ (2) it is possible to express the normalized porosity index (∅z) in terms of the porous volume to grain volume ratio (fraction). ø𝑧 = øe 1−øe (3) fzi is given by: 𝐹𝑍𝐼 = 𝑅𝑄𝐼 ∅e (4) rqi vs øz log-log plots show that the slope of a line connecting all samples with identical fzi values is one, and that the slopes of lines connecting samples with fzi values that are significantly different from the preceding one are all equal to one. it is possible to create a single hydraulic flow unit by aligning samples in a straight line that all have the same pore throat characteristics. for each hydraulic flow unit (hfu), the intercept of this line with øz = 1 reflects the mean fzi value [19]. mishrif formation was divided into four hfu or fzi, and four porosity-permeability relations are applied by different equations with powerful correlated factors for each one, as in in fig. 3 and fig. 4, the equation results of the regression analysis for the hydraulic flow units are given in table 2. table 2. permeability formulas for each hfu fzi formula r2 fzi_1 k= 710.23*øeff3.7475 0.8889 fzi_2 k= 1123.7*øeff 3.3357 0.9359 fzi_3 k = 2624.9øeff3.1939 0.8873 fzi_4 k= 64471*øeff3.6175 0.95 o. salman et al. / iraqi journal of chemical and petroleum engineering 23,4 (2022) 17 24 19 fig. 3. permeability vs. porosity cross plot for specific fzi fig. 4. rqi versus. øz cross plot 2.3. artificial neural network an artificial neural network (anns) is a computer model that tries to mimic the basic biological learning process and the specialized function of the human nervous system. an adaptive parallel information processing system, it is capable of developing associations and transformations between input and output data input and output the in an anns analysis [20]. artificial neural networks (anns) have proven to be an effective method for modeling generic relationships. they've been employed in remote sensing, biomedical engineering, and other fields [21]. anns are excellent predictors because they can learn a problem from a small number of samples and their generalizing ability allows them to make predictions based on data that was not included in their training set. anns are also stronger than typical prediction methods in dealing with incomplete or noisy data [22]. a training set is created using (water saturation sw, effective porosity phie, invasion depth di, shale volume vsh, variables as inputs and their related permeability values (known from core analysis) as desired outputs to predict permeability by using the anns algorithm which build in interactive petrophysical software v4.5. 3results and discussions 1. according to the classical technique and neural network, the permeability of the core data was much lower than the calculated permeability because it is challenging to establish a simple correlation between porosity and permeability in these formations, it is challenging to identify the permeability of heterogeneous formations using well log data. however, none of these methods can be applied to every case as shown in fig. 5 and fig. 6 a plot of prediction permeability versus core permeability of mb1and mb2, which were applied the formulas in table 1 and in fig. 7 and fig. 8 which is represented the permeability estimated by anns and permeability by core analysis. fig. 5. k-core and k –classic for xx_1 o. salman et al. / iraqi journal of chemical and petroleum engineering 23,4 (2022) 17 24 20 fig. 6. k-core and k –classic for xx _2 fig. 7. k-core and k-anns for xx _1 fig. 8. k-core and k-anns for xx _2 2. according to values of fzi four groups were identified in permeability– porosity plot and permeability formula generated for each group. each of them represent the different type of rock. the generated permeability formulas are applied in uncored wells and intervals depending on the porosity value from the logs. the produced permeability formulas in table 2 were used in the cored wells (xx-1, xx-2, xx3 and xx-4) to compare the estimated permeability values with the measured core values as illustrated in fig. 9 to fig. 12. o. salman et al. / iraqi journal of chemical and petroleum engineering 23,4 (2022) 17 24 21 fig. 9. k-core and k-fzi for xx_1 fig. 10. k-core and k-fzi for xx_2 fig. 11. k-core and k-fzi for xx_3 fig. 12. k-core and k-fzi for xx_4 o. salman et al. / iraqi journal of chemical and petroleum engineering 23,4 (2022) 17 24 22 4conclusion 1. anns and classical methods failed to give a good match between calculated permeability and core permeability because due to heterogeneity and variation in pores geometry. 2. the (fzi) gives the best results for permeability prediction because it gave good agreement between the predicted and cored values at most depth intervals of the two units in the wells, so this study has adopted the flow zone indicator (fzi) method to predict permeability in uncored wells/units. 3. using the fzi approach, mishrif reservoir is divided into s four hfus groups with high correlation coefficient (r2) for each (hfu) represents a different type of rock, which has a similar porosity and similar qualities. 4. a method based on hfus has been developed for better permeability assessment in uncored wells or uncored intervals of otherwise cored wells. the method produces good results when its limitations and applicability range are acknowledged and considered. nomenclature ann: artificial neural network fzi: flow zone indicator, μm hfu: hydraulic flow unit phie: effective porosity, fraction sw: water saturation di: invasion depth vsh: shale volume rqi: reservoir quality index, μm symbols k: permeability, md r2: correlation coefficient øz: normalized porosity, fraction øe: effective porosity, fraction references [1] d. a. alobaidi, “permeability prediction in one of iraqi carbonate reservoir using hydraulic flow units and neural networks,” iraqi journal of chemical and petroleum engineering, vol. 17, no. 1, pp. 1–11, 2016. [2] m. a. kargarpour, “carbonate reservoir characterization: an integrated approach,” j pet explor prod technol, vol. 10, no. 7, pp. 2655–2667, 2020. [3] v. t. ngo, v. d. lu, and v. m. le, “a comparison of permeability prediction methods using core analysis data for sandstone and carbonate reservoirs,” geomechanics and geophysics for geo-energy and geo-resources, vol. 4, no. 2, pp. 129–139, jun. 2018, doi: 10.1007/s40948-017-0078-y. [4] s. saffarzadeh and s. r. shadizadeh, “reservoir rock permeability prediction using support vector regression in an iranian oil field,” journal of geophysics and engineering, vol. 9, no. 3, pp. 336– 344, jun. 2012, doi: 10.1088/1742-2132/9/3/336. [5] m. m. hossain, o. al-fatlawi, d. brown, and m. ajeel, “numerical approach for the prediction of formation and hydraulic fracture properties considering elliptical flow regime in tight gas reservoirs,” 2018. [6] h. mahmood and o. al-fatlawi, “construction of comprehensive geological model for an iraqi oil reservoir,” iraqi geological journal, vol. 54, no. 2f, pp. 22–35, dec. 2021, doi: 10.46717/igj.54.2f.3ms2021-12-20. [7] b. rafik and b. kamel, “prediction of permeability and porosity from well log data using the nonparametric regression with multivariate analysis and neural network, hassi r’mel field, algeria,” egyptian journal of petroleum, vol. 26, no. 3, pp. 763–778, 2017, doi: 10.1016/j.ejpe.2016.10.013. [8] w. mustafa al-qattan and a. habeeb al mohammed, “permeability prediction by classical and flow zone indictor (fzi) methods for an iraqi gas field,” iraqi journal of chemical and petroleum engineering, vol. 18, no. 3, pp. 59–65, 2017. [9] h. abdulelah, s. mahmood, and g. hamada, “hydraulic flow units for reservoir characterization: a successful application on arab-d carbonate,” in iop conference series: materials science and engineering, jul. 2018, vol. 380, no. 1. doi: 10.1088/1757-899x/380/1/012020. [10] k. aminian, s. ameri, a. oyerokun, and b. thomas, “prediction of flow units and permeability using artificial neural networks,” 2003. [11] m. aljuboori, m. hossain, o. al-fatlawi, a. kabir, and a. radhi, “numerical simulation of gas lift optimization using genetic algorithm for a middle east oil field: feasibility study,” 2020. [12] a. a. ramadhan and a. j. mahmood, “petrophysical properties and well log interpretations of tertiary reservoir in khabaz oil field/northern iraq,” journal of engineering, vol. 26, no. 6, pp. 18–34, 2020. [13] g. jreou, “a preliminary study to evaluate mishrif carbonate reservoir of nasiriya oil field gas condensate reservoirs view project reservoir management view project,” 2013. [14] h. d. khalaf, “enhancement of oil production from mishrif reservoir in nasiriyah oil field of baghdad in partial fulfillment of the requirements for the degree of master of science in petroleum engineering,” 2009. [15] y. n. a. majeed, a. a. ramadhan, and a. j. mahmood, “comparing between permeability prediction by using classical and fzi methods/tertiary reservoir in khabaz oil field/northern iraq,” iraqi journal of oil & gas research, vol. 2, no. 1, 2022. https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/85 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/85 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/85 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/85 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/85 https://link.springer.com/article/10.1007/s13202-020-00946-w https://link.springer.com/article/10.1007/s13202-020-00946-w https://link.springer.com/article/10.1007/s13202-020-00946-w https://link.springer.com/article/10.1007/s13202-020-00946-w https://link.springer.com/article/10.1007/s40948-017-0078-y https://link.springer.com/article/10.1007/s40948-017-0078-y https://link.springer.com/article/10.1007/s40948-017-0078-y https://link.springer.com/article/10.1007/s40948-017-0078-y https://link.springer.com/article/10.1007/s40948-017-0078-y https://link.springer.com/article/10.1007/s40948-017-0078-y https://academic.oup.com/jge/article/9/3/336/5127392 https://academic.oup.com/jge/article/9/3/336/5127392 https://academic.oup.com/jge/article/9/3/336/5127392 https://academic.oup.com/jge/article/9/3/336/5127392 https://academic.oup.com/jge/article/9/3/336/5127392 https://onepetro.org/otcasia/proceedings-abstract/18otca/2-18otca/d021s007r004/179519 https://onepetro.org/otcasia/proceedings-abstract/18otca/2-18otca/d021s007r004/179519 https://onepetro.org/otcasia/proceedings-abstract/18otca/2-18otca/d021s007r004/179519 https://onepetro.org/otcasia/proceedings-abstract/18otca/2-18otca/d021s007r004/179519 https://onepetro.org/otcasia/proceedings-abstract/18otca/2-18otca/d021s007r004/179519 https://igj-iraq.org/igj/index.php/igj/article/view/594 https://igj-iraq.org/igj/index.php/igj/article/view/594 https://igj-iraq.org/igj/index.php/igj/article/view/594 https://igj-iraq.org/igj/index.php/igj/article/view/594 https://igj-iraq.org/igj/index.php/igj/article/view/594 https://www.sciencedirect.com/science/article/pii/s1110062116300290 https://www.sciencedirect.com/science/article/pii/s1110062116300290 https://www.sciencedirect.com/science/article/pii/s1110062116300290 https://www.sciencedirect.com/science/article/pii/s1110062116300290 https://www.sciencedirect.com/science/article/pii/s1110062116300290 https://www.sciencedirect.com/science/article/pii/s1110062116300290 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/66 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/66 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/66 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/66 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/66 https://iopscience.iop.org/article/10.1088/1757-899x/380/1/012020/meta https://iopscience.iop.org/article/10.1088/1757-899x/380/1/012020/meta https://iopscience.iop.org/article/10.1088/1757-899x/380/1/012020/meta https://iopscience.iop.org/article/10.1088/1757-899x/380/1/012020/meta https://iopscience.iop.org/article/10.1088/1757-899x/380/1/012020/meta https://iopscience.iop.org/article/10.1088/1757-899x/380/1/012020/meta https://onepetro.org/spewrm/proceedings-abstract/03wrm/all-03wrm/spe-83586-ms/137416 https://onepetro.org/spewrm/proceedings-abstract/03wrm/all-03wrm/spe-83586-ms/137416 https://onepetro.org/spewrm/proceedings-abstract/03wrm/all-03wrm/spe-83586-ms/137416 https://onepetro.org/iptconf/proceedings-abstract/20iptc/3-20iptc/d031s095r001/154786 https://onepetro.org/iptconf/proceedings-abstract/20iptc/3-20iptc/d031s095r001/154786 https://onepetro.org/iptconf/proceedings-abstract/20iptc/3-20iptc/d031s095r001/154786 https://onepetro.org/iptconf/proceedings-abstract/20iptc/3-20iptc/d031s095r001/154786 https://www.iasj.net/iasj/download/d557fdbeb53c9af7 https://www.iasj.net/iasj/download/d557fdbeb53c9af7 https://www.iasj.net/iasj/download/d557fdbeb53c9af7 https://www.iasj.net/iasj/download/d557fdbeb53c9af7 https://www.iasj.net/iasj/download/d557fdbeb53c9af7 https://www.researchgate.net/profile/yousif-abdul-majeed-2/publication/359823742_comparing_between_permeability_prediction_by_using_classical_and_fzi_methodstertiary_reservoir_in_khabaz_oil_field_northern_iraq_iraqi_journal_of_oil_gas_research/links/6250c74def013420666258ca/comparing-between-permeability-prediction-by-using-classical-and-fzi-methods-tertiary-reservoir-in-khabaz-oil-field-northern-iraq-iraqi-journal-of-oil-gas-research.pdf https://www.researchgate.net/profile/yousif-abdul-majeed-2/publication/359823742_comparing_between_permeability_prediction_by_using_classical_and_fzi_methodstertiary_reservoir_in_khabaz_oil_field_northern_iraq_iraqi_journal_of_oil_gas_research/links/6250c74def013420666258ca/comparing-between-permeability-prediction-by-using-classical-and-fzi-methods-tertiary-reservoir-in-khabaz-oil-field-northern-iraq-iraqi-journal-of-oil-gas-research.pdf https://www.researchgate.net/profile/yousif-abdul-majeed-2/publication/359823742_comparing_between_permeability_prediction_by_using_classical_and_fzi_methodstertiary_reservoir_in_khabaz_oil_field_northern_iraq_iraqi_journal_of_oil_gas_research/links/6250c74def013420666258ca/comparing-between-permeability-prediction-by-using-classical-and-fzi-methods-tertiary-reservoir-in-khabaz-oil-field-northern-iraq-iraqi-journal-of-oil-gas-research.pdf https://www.researchgate.net/profile/yousif-abdul-majeed-2/publication/359823742_comparing_between_permeability_prediction_by_using_classical_and_fzi_methodstertiary_reservoir_in_khabaz_oil_field_northern_iraq_iraqi_journal_of_oil_gas_research/links/6250c74def013420666258ca/comparing-between-permeability-prediction-by-using-classical-and-fzi-methods-tertiary-reservoir-in-khabaz-oil-field-northern-iraq-iraqi-journal-of-oil-gas-research.pdf https://www.researchgate.net/profile/yousif-abdul-majeed-2/publication/359823742_comparing_between_permeability_prediction_by_using_classical_and_fzi_methodstertiary_reservoir_in_khabaz_oil_field_northern_iraq_iraqi_journal_of_oil_gas_research/links/6250c74def013420666258ca/comparing-between-permeability-prediction-by-using-classical-and-fzi-methods-tertiary-reservoir-in-khabaz-oil-field-northern-iraq-iraqi-journal-of-oil-gas-research.pdf https://www.researchgate.net/profile/yousif-abdul-majeed-2/publication/359823742_comparing_between_permeability_prediction_by_using_classical_and_fzi_methodstertiary_reservoir_in_khabaz_oil_field_northern_iraq_iraqi_journal_of_oil_gas_research/links/6250c74def013420666258ca/comparing-between-permeability-prediction-by-using-classical-and-fzi-methods-tertiary-reservoir-in-khabaz-oil-field-northern-iraq-iraqi-journal-of-oil-gas-research.pdf o. salman et al. / iraqi journal of chemical and petroleum engineering 23,4 (2022) 17 24 23 [16] j. o. amaefule, m. altunbay, d. g. kersey, and d. k. keelan, “spe 26436 enhanced reservoir description: using core and log data to identify hydraulic (flow) units and predict permeability in uncored intervals/wells,” 1993. [17] a. a. bhatti et al., “permeability prediction using hydraulic flow units and electrofacies analysis,” energy geoscience, vol. 1, no. 1–2, pp. 81–91, 2020. [18] s. n. al-jawad and a. h. saleh, “flow units and rock type for reservoir characterization in carbonate reservoir: case study, south of iraq,” j pet explor prod technol, vol. 10, no. 1, pp. 1–20, jan. 2020, doi: 10.1007/s13202-019-0736-4. [19] h. ali baker, s. noori al-jawad, and z. imad murtadha, “permeability prediction in carbonate reservoir rock using fzi,” iraqi journal of chemical and petroleum engineering, vol. 14, no. 3, pp. 49–54, 2013. [20] s. mohaghegh, r. arefi, l. bilgesu, s. ameri, d. rose, and v. u. west, “design and development of an artificial neural network for estimation of formation permeability,” 1995. [21] o. isaac abiodun, a. jantan, a. esther omolara, k. victoria dada, n. abdelatif mohamed, and h. arshad, “state-of-the-art in artificial neural network applications: a survey,” heliyon, vol. 4, p. 938, 2018, doi: 10.1016/j.heliyon.2018. [22] z. huang, j. shimeld, m. williamson, and j. katsube, “permeability prediction with artificial neural network modeling in the venture gas field, offshore eastern canada,” geophysics, vol. 61, no. 2, pp. 422–436, mar. 1996, doi: 10.1190/1.1443970. https://onepetro.org/speatce/proceedings-abstract/93spe/all-93spe/spe-26436-ms/55155 https://onepetro.org/speatce/proceedings-abstract/93spe/all-93spe/spe-26436-ms/55155 https://onepetro.org/speatce/proceedings-abstract/93spe/all-93spe/spe-26436-ms/55155 https://onepetro.org/speatce/proceedings-abstract/93spe/all-93spe/spe-26436-ms/55155 https://onepetro.org/speatce/proceedings-abstract/93spe/all-93spe/spe-26436-ms/55155 https://www.sciencedirect.com/science/article/pii/s2666759220300056 https://www.sciencedirect.com/science/article/pii/s2666759220300056 https://www.sciencedirect.com/science/article/pii/s2666759220300056 https://link.springer.com/article/10.1007/s13202-019-0736-4 https://link.springer.com/article/10.1007/s13202-019-0736-4 https://link.springer.com/article/10.1007/s13202-019-0736-4 https://link.springer.com/article/10.1007/s13202-019-0736-4 https://link.springer.com/article/10.1007/s13202-019-0736-4 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/318 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/318 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/318 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/318 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/318 https://onepetro.org/ca/article-abstract/7/06/151/70238/design-and-development-of-an-artificial-neural https://onepetro.org/ca/article-abstract/7/06/151/70238/design-and-development-of-an-artificial-neural https://onepetro.org/ca/article-abstract/7/06/151/70238/design-and-development-of-an-artificial-neural https://onepetro.org/ca/article-abstract/7/06/151/70238/design-and-development-of-an-artificial-neural https://www.sciencedirect.com/science/article/pii/s2405844018332067 https://www.sciencedirect.com/science/article/pii/s2405844018332067 https://www.sciencedirect.com/science/article/pii/s2405844018332067 https://www.sciencedirect.com/science/article/pii/s2405844018332067 https://www.sciencedirect.com/science/article/pii/s2405844018332067 https://library.seg.org/doi/abs/10.1190/1.1443970 https://library.seg.org/doi/abs/10.1190/1.1443970 https://library.seg.org/doi/abs/10.1190/1.1443970 https://library.seg.org/doi/abs/10.1190/1.1443970 https://library.seg.org/doi/abs/10.1190/1.1443970 o. salman et al. / iraqi journal of chemical and petroleum engineering 23,4 (2022) 17 24 24 وحدات و يةالتنبؤ بالنفاذية في أحد مكامن الكاربونية العراقية باستخدام الطرق التقليد التدفق الهيدروليكي وطرق الشبكة العصبية االصطناعية 3سمير الجواد و 1,2عمر فالح حسن ,1عهود سلمان غدادبجامعة -كلية الهندسة -النفط قسم هندسة ١ جامعة كيرتن ٢ وزارة النفط العراقية ٣ الخالصة يةةةةحم ت ديةةةةد فق ةةةةا تةةةةدف فةةةة ت اةةةةي ال ن ةةةةن أل ةةةةن ر هةةةةا األساسةةةةية هةةةة مةةةةن ال عل مةةةةا النفاذيةةةةة م تة. مه ةة للغايةةمنلفةة للحن ةب بالنفاذيةة ، فةن ال اجةة ىلةر ةري دقي ةة و يةرالهيدروكرب وحج ه، ولهةاا السة اخحيار من ةن مرةرف فة جنة ق اةري العةراي هت ةال هةاة الدراسةة، واسةحند الدراسةة ىلةر بياقةا مةن فربعةة بةار ر الطر ةةة اهولةةر هةة الطر ةةة الح ليديةةة لحطةة ، تنةةاقه هةةاة الدراسةةة ةةدة ةةري للحن ةةب بالنفاذيةةة. تخحةةري ال ن ةةن خ ر والطر ةة الااقيةة هة باه ح ةاد لةر كحلةة الصة .اهسةحراتيجيا الصلة بين النفاذية وال سامية ه واحةدة مةن بنة و ر ةة فخةرل للحن ةب بالنفاذيةة هة بالرة .رال ياقا من اللباق وسجال اآلبةاومبار منط ة الحدف باسحخدال .العص ية اهاطناعية حدف الهيدرولين ألقهفظهر النحائج ف ر ة مبار منط ة الحدف ه مقياس فعال ل ساق وحدا ال قد و ل م ارقة بالطري األخر يعح د لر الخصائص الجي ل جية لل ادة وهندسة ال سال ال حن ة لكحلة الصخ ر .اظهر قحائج م لة ل ساق النفاذية م ارقة بالطري اهخرل .النفاذية، مبار منط ة الحدف ، الربنة العص ية اهاطناعية: الدالة الكل ا iraqi journal of chemical and petroleum engineering vol.18 no.1 (march 2017) 57 69 issn: 1997-4884 preparation activated carbon from scrap tires by microwave assisted koh activation for removal emulsified oil najwa saber majeed, huda adil sabbar and nawar o. a. al-musawi* chemical engineering department-college of engineering-university of baghdad-iraq *civil engineering department-college of engineering-university of baghdad-iraq abstract in this paper activated carbon adsorbents produced from waste tires by chemical activation methods and application of microwave assisted koh activation. the influence of radiation time, radiation power, and impregnation ratio on the yield and oil removal which is one of the major environmental issues nowadays and considered persistent environmental contaminants and many of them are suspected of being carcinogenic. based on box-wilson central composite design, polynomial models were developed to correlate the process variables to the two responses. from the analysis of variance the significant variables on each response were identified. optimum conditions of 4 min radiation time, 700 w radiation power and 0.5 g/g impregnation ratio gave 205.8749 mg/g oil removal and 35.19618 % yield. the characteristics of the ac were examined by pore structure analysis, and scanning electron microscopy (sem).the bet surface area and total pore volume were identified to be 374.594 m²/g and 0.2039 m³/g, respectively. key words: waste tires, activated carbon, activation, microwave, optimization, adsorption. introduction one of the major environmental issues nowadays is the vast and widespread occurrence of oil in industrial wastewater and ground water. oils (both mineral and synthetic) are considered persistent environmental contaminants and many of them are suspected of being carcinogenic [1], the removal of oily pollutants from wastewater poses a problem, particularly when they are present in low concentrations, such as in industrial water. reliability and its inexpensiveness, the adsorption technology is extensively used in oil removal. traditionally, activated carbon has been widely used as an adsorbent for removing [2]. activated carbon is a material that is produced from carbonaceous source materials, such as coal, coconuts, nutshells, peat, wood, and lignite. it has highly developed internal surface area and porosity, its pore volume typically ranges from 0.20 to 0.60 cm 3 /gm, and has been found to be as large as 1cm 3 /gm. its surface area ranges typically from 300 to 1500 m 2 /gm [3]. a large capacity for adsorbing chemicals from gases and liquids. university of baghdad college of engineering iraqi journal of chemical and petroleum engineering https://en.wikipedia.org/wiki/peat https://en.wikipedia.org/wiki/wood https://en.wikipedia.org/wiki/lignite preparation activated carbon from scrap tires by microwave assisted koh activation for removal emulsified oil 58 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net activated carbons are extremely versatile adsorbents of industrial significance and are used in a wide range of applications which are concerned principally with removal of undesired species by adsorption from liquids or gases, in order to effect purification or the recovery of chemical constituents [3], the forms and characteristics of activated carbon are highly dependent on the precursors and activation methods adopted for its production [5] it is used in many fields both in industry and daily life of every person. the usage of carbon adsorbents depend on their surface area, pore size distribution and chemical surface characteristics. the quality (surface area, pore size distribution and hence adsorptive properties) of it are directly related to the nature of starting material, the type of the production method and the temperature of production [6]. waste tires are good starting materials for activated carbon production because of it containing a high fixed carbon content and cheap and available in addition to maintaining the environment from the risks of throwing tires [7]. the preparation of ac involves of two stages, namely pyrolysis and activation [8]. single step pyrolysis usually applied in the preparation of activated carbon using chemical activation method, which has low energy consumption, cheap shorter process duration and modest surface area and porosity. however, the conventional preparation of activated carbon using physical activation method was based on two step pyrolysis where carbonization and activation process takes place separately which has high energy consumption, expensive, longer process duration and high surface area and porosity. the product quality of two step pyrolysis is better compared to the single step pyrolysis [9]. the thermal process may need several hours, even up to a week to make the desired level of activation another trouble related to the furnace is that the surface heating does not ensure a regular temperature for various shapes and sizes of samples [10]. therefore, it is necessary to find a rapid and easy route for the preparation of ac. although microwave heating is today a mature technique which finds wide applications in the area of material science, food processing and analytical chemistry [11], the major advantage of using microwave heating is: heat emitted from microwave be fast and uniform, direct using of big-sized feedstock, treatment of nonhomogeneous wastes, minimize waste and material recovery, best production quality, production of new materials and products .total cost effectiveness, savings, and reduce dangers to humans and the environment [12]. in addition to use microwave heating in the production of char was found to produce desirable changes in its textural and chemical properties comparing to the char produced by conventional met hods. for instance, a cleaner porous structure has been reported by miura et al., 2004 in the pyrolysis of wood, [13]. (rsm) approach. rsm has been found to be a useful tool to study the interaction of two or more factors [14]. a standard rsm design called boxwilson central composite design is suitable for fitting a quadratic surface and it helps to optimize the effective parameters with a minimum number of experiments, as well as to analyze the interaction between the parameter [15]. rsm has just recently been used for the optimization of activated carbon production from rattan sawdust [14]. the aim of this work is to optimize the preparation conditions of ac from http://www.iasj.net/ najwa saber majeed, huda adil sabbar and nawar o. a. al-musawi -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 59 scrape tires by chemical activation for the removal of emulsified oil from waste water. the effects of radiation time, radiation power and impregnation ratio are also studied simultaneously to obtain a high oil removal using the box-wilson central composite design. materials and method materials scrape tires were used as the precursor for the preparation of ac. waste tires were washed with water to get rid of impurities, then shredded using an electrical drill (bosch 305) adopted with crushing disk and sieved .fraction with particle size of (1.18-2.36) mm was selected for the preparation. potassium hydroxide (koh), (purchased from didactic company, espuma) mw=56.10 of purity 99.9% was used as a chemical activator. span 85 and tween-80 materials that increases the emulsifying. cyclohexane (c6h12) which used as the extraction solvent, other chemical used such as hydrochloric acid were from analytical grades. . preparation of activated carbon a weighed amount (2g) of dried waste tires was mixed with 10 ml of koh solution at various impregnation ratios (0.5 – 1.5 g/g) for 24 h at room temperature. the samples were next placed in an dryer (model ih – 100, england) at 110 °c until completely dried then the dry samples were activated by using a quartz glass reactor in microwave at different radiation powers (400–700w) for different radiation times (4_12min), samsung mode (lms23f301e), malaisie, it can reach a maximum power of (800 watt) the upper surface of microwave had a removable cover connected to a stainless steel pipe of 5mm inside diameter from which pyrolysis gases were exit ,with quartz glass reactor 2.5 cm diameter x 12.5 cm length as it is shown in figure 1. after activation, the sample was withdrawn from the oven and allowed to cool. the sample was mixed with 0.1m hcl solution at 10 mg/l solid to liquid ratio. the mixture was left overnight at room temperature, and then filtered and subsequently the sample was repeatedly washed with distilled water to remove residual organic matters and alkalis, until the ph of filtrate reached (6.5 – 7). after that, the sample was dried at 110cº for 24 h. and subsequently was weighed. finally the sample was stored in tightly closed bottles. fig. 1: photographic picture of microwave unit for preparation of activated carbon process performance the performance of chemical activation process was determined by the product yield, along with its removal oil. yield the yield is defined as the ratio of final weight of the obtained product after washing and drying to the weight of dried precursor initially used. the yield of ac was calculated based on the following equation: yield (%) = …(1) where wf and wo are the weight of final ac product (g) and the weight of scrape tires (g), respectively. http://www.iasj.net/ preparation activated carbon from scrap tires by microwave assisted koh activation for removal emulsified oil 60 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net removal of oil a solution of oily water prepared by mixing 0.225g of the motor oil and 0.025 of span85 and tween80 (which increase the stability of the emulsion) with 500 ml of water to prepared 500 ppm. the mixture was then stabilized in laboratory homogenizer disperser at 10000 rpm speed for 30 second. the resultant solution was milky white, which exhibited the character of chemically stabilized solution added 0.5gram of activated carbon to 200 ml of the resulting mixture(500 ppm) and then stirred with a magnetic stirrer (400 rpm) for 4 hour then the solution leaves a period of time and then be pulled 100 ml from the central region to avoid impurities. a sample of (100 ml) of solution was placed in conical flasks of (250 ml) and added drops of (1m)of hcl to neutralize the solution, and to extract the oil (10 ml) of cyclohexane, then it was shocked by hand for one minute and pulled a sample of the cyclohexane was added accumulated in the upper region for examination oil concentration by using td500dtm oil in water meter. the amount of adsorption at equilibrium, qe (mg/g), was found using equation 2: = …(2) where c0 and ce (mg/l) are the liquid-phase concentrations of oil at initial and equilibrium, respectively. v (l) is the volume of the solution and w (g) is the mass of activated carbon. adsorption isotherms that were carried out in a set of 700 ml emulsion oil in water at 500ppm with different weights of activated carbon (0.35, 1.75, 3.5, 5.25, and 7) gram were placed in these beakers, at 400rpm and ph equal 7. similarly the concentration of oil in water was calculated at different time (10 min, 30 min, 60 min, 90 min, 120 min, and 24 h) and by using equation 2 the amount of adsorption at equilibrium, qₑ (mg/g). experimental design in order to organize the experiments of ac preparation from scrap tires, a standard rsm design, known as box wilson central composite design was adopted. this design can reduce the number of experimental trails needed to evaluate multiple parameters and their interactions [16]. box-wilson design consists of 2n factorial points, 2n axial points, and one center point, where n is the numbers of variables. in order to design the experiments, the operating range of variables must be specified, thus: radiation power x1 (400-700 w), radiation and impregnation ratio x2 (0.5-1.5 g/g) radiation time x3 (4-12 min). the total number of experiments n is computed according to the following equation: n= +2n+1 …(3) the relationship between the coded variable and the corresponding real variable is as follows: …(4) characterization of activated carbon 1. total surface area surface area is one of the key indicators attributed to the adsorptive properties of porous materials [17], it generally calculated by the bet method (brunauer, emmett and teller 1). this method works at the lowpressure range of the adsorption isotherm of a molecule of known dimensions (commonly nitrogen). nitrogen adsorption experiments were done to compute the specific surface area of the test samples using a quantachrome nova-1200 instrument http://www.iasj.net/ najwa saber majeed, huda adil sabbar and nawar o. a. al-musawi -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 61 at 77k. the samples were out gassed overnight at 180 °c before the adsorption measurements. the bet model was used to be suitable for the nitrogen adsorption isotherms and estimate the specific surface area of the samples [18]. 2. pore size distribution pores in different sizes are important to the adsorbents overall capacity in adsorption processes. the presence of microand mesopores in activated carbons enhance the adsorption of large adsorbates [7]. 3. capacity capacity it is the amount which the adsorbent taken up from adsorbate by per adsorbent. it depends on the initial condition of the adsorbent, the fluid phase concentration and temperature. adsorption capacity data are gathered at various adsorbate concentrations and a fixed temperature, and the data are plotted as an isotherm (loading versus concentration at constant temperature). 4. bulk density bulk density is defined as the ratio of the mass of the material to the total volume occupied by material. the total volume corresponds to the pore and inter-particle volume. bulk density of the matter varies depending on it’s composition. results and discussion model fitting and statistical analysis for chemical activation sample the response of experiments conducted according to box – wilson method, which represented by oil removal and activated carbon yield, is fitted to a second and third order polynomial mathematical model and the optimum response is calculated from this model, it determined the effect of each parameter. at first the predictions equation (y=a+bx) used which represent first order equation for independent studied variables (power: x1, ratio: x2, time: x3, responsible variables: y and constant: a, so predictions equation become: y=const+b1*x1+b2*x2+b3*x …(5) then second order polynomial mathematical model applied which give had form for three variable more accurate. y= bₒ + b1 x1 + b2 x2 + b3 x3 + b4 x1 x2 + b5 x1 x3 + b6 x2 x3+ b7 x1 2 + b8 x2 2 + b9 x3 2 …(6) ʃ x1 / n = ʃ x2 / n = ʃ x3 / n = ʃ x1 x2 / n = ʃ x1 x3 / n = ʃ x2 x3 / n = 0, and: ʃ x1 2 / n = ʃ x2 2 / n = ʃ x3 2 / n = 0.933 the equation 6 become: y= y+ b1 x1 + b2 x2 + b3 x3 + b4 x1 x2 + b5 x1 x3 + b6 x2 x3 + b7 (x12 – 0.933) + b8 (x22 – 0.933) + b9 (x32 – 0.933) …(7) and third order y=const+b1*x1+b2*x2+b3*x3+b4 *x1*x2+b5*x1*x3+b6*x2*x3+b7 *(x1**2-0.933)+b8*(x2**2-0.933) +b9*(x3**2-0.933)+b10*(x1**3)+ b11*(x2**3)+b12*(x3**3)+b13*x1 *x2*x3 …(8) it used above equations which get to the correlation factor nearer to one. the final form becomes: …(9) http://www.iasj.net/ preparation activated carbon from scrap tires by microwave assisted koh activation for removal emulsified oil 62 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net …(10) the table 1 show values of the independent variables corresponding to the final form of the equation of yield and oil removal. table 1: values of the independent variables corresponding to the final form of the equation of yield and oil removal table 1a: values of the independent variables corresponding to the final form of the equation of yield and oil removal coded variables real variables yield (%) oil removal (mg ∕g ) y (coded variables) y (coded variables) no x1 x2 x3 x1 x2 x3 y residuals y residuals 1 1 1 -1 463.4 0.71 5.7 88 86.11463788 1.885362 194.92 195.5772812 -0.65728 2 -1 -1 1 636.6 0.71 5.7 52 50.11463588 1.885364 198.2 198.2947812 -0.09478 3 1 -1 1 463.4 1.3 5.7 62 60.11463988 1.88536 185.2 185.2947812 -0.09478 4 -1 1 1 636.6 1.3 5.7 48.7 46.81463788 1.885362 190.48 191.1372812 -0.65728 5 1 1 1 463.4 0.71 10.3 54.2 52.31463788 1.885362 191.96 192.0547812 -0.09478 6 -1.732 0 0 636.6 0.71 10.3 74 72.11463588 1.885364 187.56 188.2172812 -0.65728 7 1.732 0 0 463.4 1.3 10.3 93.16 91.27463988 1.88536 195.8 196.4572812 -0.65728 8 0 -1.732 0 636.6 1.3 10.3 31 29.11463788 1.885362 195.9 195.9947812 -0.09478 9 0 1.732 0 400 1 8 65.9 68.41395525 -2.51396 194.52 194.0185477 0.501452 10 0 0 -1.732 700 1 8 68 70.51395432 -2.51395 195.52 195.0185472 0.501453 11 0 0 1.732 550 0.5 8 42.2 44.7139608 -2.51396 196 195.498549 0.501451 12 0 0 0 550 1.5 8 55 57.51396396 -2.51396 192.52 192.0185472 0.501453 13 1 1 -1 550 1 4 80 82.51395366 -2.51395 187.44 186.9385458 0.501454 14 -1 -1 1 550 1 12 39.8 42.31395515 -2.51396 194.28 193.7785493 0.501451 15 1 -1 1 550 1 8 63.6 63.59910988 0.00089 193.16 193.1601552 -0.00016 r=.992415272 r=.99321325 y: observed value y: calculated value table 1b: values of the independent variables corresponding to the final form of the equation of yield and oil removal coded variables real variables yield (%) (real variables) oil removal (mg ∕g) ( real variables) no x1 x2 x3 x1 x2 x3 y residuals y residuals 1 1 1 -1 463.4 0.71 5.7 87.0284781 0.971521903 195.05277 0.1327663 2 -1 -1 1 636.6 0.71 5.7 52.44198703 -0.441987025 197.45902 -0.7409794 3 1 -1 1 463.4 1.3 5.7 60.86207183 1.13792817 184.41962 -0.7803832 4 -1 1 1 636.6 1.3 5.7 49.04515041 -0.345150407 190.08274 -0.3972646 5 1 1 1 463.4 0.71 10.3 53.5071943 0.692805702 192.97879 1.0187855 6 -1.732 0 0 636.6 0.71 10.3 74.81534444 -0.815344435 188.95471 1.3947126 7 1.732 0 0 463.4 1.3 10.3 92.39491428 0.76508572 197.10518 1.3051821 8 0 -1.732 0 636.6 1.3 10.3 31.71814296 -0.718142957 196.33797 0.4379737 9 0 1.732 0 400 1 8 69.08168428 -3.181684283 193.75079 -0.7692064 10 0 0 -1.732 700 1 8 73.81767748 -5.817677483 195.12248 -0.3975164 11 0 0 1.732 550 0.5 8 46.42729498 -4.227294983 195.05562 -0.9443824 12 0 0 0 550 1.5 8 59.25529498 -4.255294983 192.27897 -0.2410314 13 1 1 -1 550 1 4 83.92604498 -3.926044983 188.57718 1.1371786 14 -1 -1 1 550 1 12 44.41254498 -4.612544983 191.99552 -2.2844774 15 1 -1 1 550 1 8 64.98529498 -1.385294983 193.10464 -0.0553614 r=0.99204284 r=0.99321325 y: observed value y: calculated value process optimization at optimum conditions, the prepared ac should have a high yield and high removal oil. however, it is difficult to optimize both these responses under the same condition because the interest region of variables is different, when oil removal increases, carbon yield http://www.iasj.net/ najwa saber majeed, huda adil sabbar and nawar o. a. al-musawi -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 63 decrease and vice versa. therefore, the optimum conditions have been determined depending on achieving high removal oil. the optimum operating conditions has been determined by studying each independent variable alone [19]. thus, the optimum conditions corresponding to a maximum removal oil are 4 min radiation time, 700 w radiation power, and 0.5 g/g impregnation ratio which determined by study every parameter with changing two other parameter as show in table 2. at these conditions, 205.8749 mg/g oil removal with 35.19618 % yield were reported experimentally. effect of process variables effect of radiation time the effect of radiation time on yield and oil removal of prepared activated carbon at different radiation powers and different impregnation ratio is shown in figure 2. shows that the yield of ac decreases with increasing of radiation time at impregnation ratio (0.5, 0.75, 1, 1.25, and 1.5) g ∕g. at 400 w radiation power, the radiation time increasing from 4 to 12 min leads to decreases in yield from 88 to 70 % when impregnation ratio equal 0.5 g ∕g. this is probably due to rapid evolution of volatile materials to form stable compounds, and this situation corresponds to the explanation by foo and hameed [20]. they showed that a steep decrease in yield occurs for production of ac from coconut husk by microwave koh activation [3]. fig. 2: effect of radiation time on yield at different impregnation ratio (radiation power=400 w) the effects of radiation time on oil removal are demonstrated in figure 3 that show oil removal increase with increasing radiation time at higher impregnation ratio and it decrease with increase radiation time at low impregnation ratio. at radiation power 400 w, at impregnation ratio equal 1.5 g ∕g, oil removal is demonstrably increase from 170.28 to 205.144 mg∕ g while at impregnation ratio equal 0.5 g ∕g oil removal decrease from 199.5987 to 190.94 mg/g with increase radiation time 4-12 min .at higher impregnation ratio, prolonging radiation time promotes an acceleration of temperature or energy, which in turn increase the reaction rates , de volatilization and led to opening of micropores and mesopores which resulted in expansion of the average diameter thus developed the porosity and rudimentary of the pore structure. but in low impregnation ratios, oil removal decreased with increasing radiation time, probably due to turn mesopores to macropores and sintering effect, which hugely crashed the pore walls between relative pores (foo and hameed, 2012) [20]. fig. 3: effect of radiation time on oil removal at variable impregnation ratio (radiation power=400 w) effect of radiation power the effect of radiation power on yield and oil removal of prepared activated carbon at different radiation time is shown in figures 4 and 5. figure 4 shows that the yield of ac decreases with increasing of radiation power at radiation time 4-12 min. http://www.iasj.net/ preparation activated carbon from scrap tires by microwave assisted koh activation for removal emulsified oil 64 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net at impregnation ratio 0.5 g/g when radiation power change from 400 to 700 w, yield decrease from 86 to 55% at radiation time equal to 4 min, it illustrated that loss of the volatile materials with increasing power. then the lower rate of yield decrease was noticed where a stable structure is formed. however, at a high radiation power over-gasification might occur causing destruction of pore structures, thus the removal oil and carbon yield decreased gradually. the weight loss of carbon increased proportionally to the microwave power, mainly attributable to the robust reaction at higher thermal radiation which massive devolatilization, dehydration and putridity [20]. fig. 4: effect of radiation power on yield at variable radiation time (impregnation ratio =0.5) the effects of radiation power on oil removal are demonstrated in figure 5 that show oil removal increase with increasing radiation power at low radiation time. but in high radiation time, oil removal decrease with increasing radiation power. at impregnation ratio equal 0.5 g/g, oil removal increased from 199.5987 to 205.87 mg/g at 4 min radiation time while oil removal decrease from 190.949 to 177.8548 mg/g at 12 min radiation time with increases the radiation power from (400-700), at low radiation time, increasing the microwave power was to induced higher internal and volumetric heating leading to the development of new pores thereby enhancing the adsorption capacity and possibly ascribed to the joint effect of internal and volumetric heating responsible for the expansion of the carbon structure creation of raise porosity and a bigger surface area [20]. but in high radiation time increase in power might be due to the sintering effect at high power, followed by shrinkage of the char, and realignment of the carbon structure which resulted in reduced pore areas as well as volume this situation corresponds to the explanation by deng et al. [21] who reported for mb uptake on ac prepared from cotton stalk by microwave assisted koh activation. fig. 5: effect of radiation power on oil removal at different radiation time (impregnation ratio =0.5) effect of impregnation ratio the effect of impregnation ratio on yield and oil removal of prepared activated carbon at different radiation time and different radiation power is shown in figures 6 and 7. figure 6 shows that the yield of ac decreases with increasing of radiation ratio at radiation time 4 and 6 min at radiation power (400, 475, 550,636.6, and 700) watt. at 4 min radiation time yield decrease from 91.3 to 61.6% when impregnation ratio increase from 0.5 to 1.5 g/g at 400 watt power radiation this decrease is due to the continuous removal of tar material from the pores.. this behavior agrees with results obtained by sudaryanto [22] for ac production http://www.iasj.net/ najwa saber majeed, huda adil sabbar and nawar o. a. al-musawi -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 65 from cassava peel by chemical activation with potassium hydroxide. this is the same in the case at radiation time 6 min with decrease in yield with increase radiation time. fig. 6: effect impregnation ratio on yield at different radiation power (radiation time =4min) the effects of impregnation ratio on oil removal are demonstrated in figure 7 that show oil removal increase with increase impregnation ratio at height radiation time, but at low radiation time it decrease with increase impregnation ratio. figure 8, at 12 min radiation time and 400 w radiation power, removal oil increase from 190.95 to 205.149 mg/g while oil removal decrease from 199.59 to 170.2881 mg/g at 4 min radiation time. at height radiation time, the potassium compound created during the activation step would spread into the internal structure of tires matrix and expansion existing pores. therefore, by rising the ratio of koh to tires, the activation process would play a key role in pore modelling. the pore width was successively broadened and new micropores mesopores were formed in the off-center pore walls, giving a self-sustaining increase in bet surface area and pore volume. correspondingly, but in low radiation time, the oil removal was extra enhanced., increase koh and metallic potassium did not take enough time to gas left in the carbon surface caused blockage of the pores leading to carbon burn of and mutation of microporesmesopores into macropores lessening the oil removal [20]. fig. 7: effect impregnation ratio on oil removal at variable radiation power (radiation time =4min) fig. 8: effect impregnation ratio on oil removal at variable radiation power (radiation time =12min) table 2: studying best variable that achieve maximums oil removal constant variable best variables in constant certain variable maxim oil removal(mg/ g) effect of radiation time radiation power (watt) impregnation ratio(g/g) radiation time (min) maxim oil removal (mg/g) 400 1.5 12 205.144 475 1.5 12 203.26 550 1.5 12 202.04 625 0.5 4 203.068 700 0.5 4 205.87 effect of radiation power impregnati on ratio(g/g) impregnation time(min) radiation power (watt) maxim oil removal (mg/g) 0.5 4 700 205.87 0.75 4 700 200 1 12 400 197 1.25 12 400 201 1.5 12 400 205.14 effect of impregnation ratio impregnation time(min) radiation power (watt) impregnation ratio(g/g) maxim oil removal (mg/g) 4 700 0.5 205.87 6 700 0.5 200.98 8 400 0.5 198.09 10 700 1.5 199.854 12 400 1.5 205.144 http://www.iasj.net/ preparation activated carbon from scrap tires by microwave assisted koh activation for removal emulsified oil 66 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net adsorption isotherms of emulsified oil on activated carbon prepared at optimum condition the adsorption isotherm is the most extensively employed method for representing the equilibrium states of an adsorption system. the adsorption isotherm gives useful information regarding the adsorbate, the adsorbent, and the adsorption process, the results of this fitting, as summarized in table 3 show that sips isotherm has the highest r 2 value as compared to that of both langmuir and freundlich isotherms. the sips model correlates the equilibrium data with r 2 values. fig. 9: sips adsorption isotherm of oil on activated carbon at 25 table 3: isotherm parameters for oil adsorption onto activated carbon with the correlation coefficient model parameters values langmuir kl(l/mg) 0.003054 q,max(mg/g) 230.5 r 2 0.993 rl 0.395 freundlich ⁄ kf 0.571428 n 0.9639 r 2 0.99 sips ⁄ ⁄ qm(mg/g) 265 ks((l/mg) 1/m ) 0.002155 n 0.96445 r 2 0.997 fig. 10: adsorption isotherm for oil by activated carbon ( =500mg/l, temp=25 and dp= 1.18-2.36mm) characterization of activated carbon bet surface area and pore volume the bet surface area, total pore volume of ac prepared at optimum conditions are found to be 374.594 m²/g, 0.2039 m³/g these values higher than that reported by skodras et al [22] who show the bet surface area of activated carbon from tires by koh activation were 358.5 m 2 /g ac. table 4 shows the comparison on the application of microwave heating to the production of activated carbon from different material. table 4: summary of previous works on preparation of activated carbons produced by waste tires [5] references activating agent activation conditions bet surface area (m2 / g) this study koh power=625w, time=6min and ratio=0.75 g/g 374.59 skodras et al., (2007) steam temp=900 ,time= 2 358.5 helleur et al., (2001) steam co2 temp=900 ,time=3 temp=875 ,time= 7 272 270 sainz-diaz and griffiths, (2000) co2 temp=1000 ,time=5 temp=1000 ,time=7 431 284 cunliffe and williams, (1999) steam temp=935 time= 640 streat et al., (1995) steam temp=800 ,time= 24 temp=900 ,time= 18 346 155 belgacem et al., 2013 phosphoric acid temp=650 time= 2hand 30min 400 http://www.iasj.net/ najwa saber majeed, huda adil sabbar and nawar o. a. al-musawi -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 67 surface morphology figures 11a and b show sem images of scrap tires and ac production by two ways: physical and chemical activation methods. it can be found that the surface of tires is free of any pores, constricted and blocked by deposited tray substance. however, the microwave irradiation sample demonstrated a well-developed and uniform surface, forming an orderly pore structure. the development of porosity is associated with gasification according to the following reduction reactions [23]: 6koh + 2c → 2k + 3h2 +2k2co3 k2co3 was reduced by carbons to form k, k2o, co and co2 so that more pores were formed as follows: k2co3 +2c → 2k + 3co k2co3→ k2o + co2 it was assumed that metallic potassium k formed during the gasification process would diffuse into the internal structure of carbon matrix widening the existing pores and created new porosities. figure 11b also shows that the surface of prepared carbon contains some cavities which are resulted from the evaporation of impregnated koh derived compounds, leaving the space previously occupied by the reagent. theses cavities provide channels for the adsorbate molecules to access the micropores and mesopores inside a carbon particle. (a) (b) (c) fig. 11: sem micrographs (10 kx) of srape tires (a) and (50kx) ac by physcal method (b) ac method (c) by chemicl conclusion activated carbons were prepared from scrape tires by microwave assisted koh activation. 205.8749 mg/g removal oil with corresponding yield of 35.1961 % were obtained at optimum conditions of 4 min radiation time, 700 w radiation power, and 0.5 g/g impregnation ratio. also, the http://www.iasj.net/ preparation activated carbon from scrap tires by microwave assisted koh activation for removal emulsified oil 68 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net surface area, pore volume of ac were 374.59 m²/g, 0.2039 m³/g .box-wilson central composite design was adopted for arrangement of preparation experiment. two second order polynomial models were successfully used to correlate the process variables to the two responses. acknowledgement we gratefully acknowledge department of chemical engineering and university of baghdad for assist and support of this work. references 1. harvey, r. g. (1991). polycyclic aromatic hydrocarbons: chemistry and carcinogenicity. cambridge university press,cambridge, england. 2. simonović, b. r., aranđelović, d., jovanović, m., kovačević, b., pezo, l., & jovanović, a. (2009). removal of mineral oil and wastewater pollutants using hard coal. chemical industry and chemical engineering quarterly, 15(2), 57-62. 3. kareem r.a. (2014)" sustainable production of local adsorbent material from waste tires for removal of lead from aqueous solution". university of baghdad. college of engineering. m.sc. thesis. 4. manocha s. m. (2003). porous carbons. sadhana, 28(1-2), 335-348. 5. abbas a.f. 2014," preparation of activated carbon from date stones by k2co3 activation for methylene blue dye adsorption", m.sc. thesis ,college of engineering, baghdad university. 6. yagsi n. u. (2004). production and characterization of activated carbon from apricot stones (doctoral dissertation, middle east technical university). 7. mui, e. l., ko, d. c., & mckay, g. (2004). production of active carbons from waste tyres––a review. carbon 8. t.h. liou, (2010), development of mesoporous structure and high adsorption capacity of biomass based activated carbon by phosphoric acid and zinc chloride activation, chem. eng. j. 158(2), 129-142. 9. hameed, b. h., tan, i. a.w. and ahmed, a. l.( 2009) “preparation of oil palm empty fruit bunch. based activated carbon for removal of 2, 4, 6trichlorophenol:optimization using response surface. 10. chaied m. a.(2015)" microwave assisted preparation of activated carbon from phragmites (reed) for antibiotics adsorption" ,m.sc. thesis ,college of engineering, baghdad university. 11. m. komorowska, g.d. stefanidies, t. van gerven, a. l. stankiewicz, (2009), influence of microwave irradiation on a polyesterification reaction, chem. eng. j. 15 (3), 859-866. 12. fernández, y., arenillas, a., & menéndez, j. á. (2011). microwave heating applied to pyrolysis, advances in induction and microwave heating of mineral and organic materials, stanisław grundas (ed.), isbn: 978-953-307522-8, intech. 13. miura, m., kaga, h., sakurai, a., kakuchi, t. i. & takahashi, k. i. 2004. rapid pyrolysis of wood block by microwave heating. journal of analytical and applied pyrolysis ,71, 187-199. 14. a. a. ahmad, b. h. hameed, a. l. ahmed, (2009), removal of disperses dye from aqueous solution using waste derived activated carbon: optimization study, j. hazard. mater.170, 612-619. http://www.iasj.net/ najwa saber majeed, huda adil sabbar and nawar o. a. al-musawi -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 69 15. a. m. m. varagas , c. a. garcia , e. m. reis , e. lenzi , w.f. costa , v. c. almeida , (2010), naoh activated carbon from flamboyant (delonixregia) pods ; optimization of preparation condition using central composit rotatable design , chem. eng. j. 162,43-50. 16. tan i. a. w., ahmed a. l., hameed b. h., (2008) , preparation of activated carbon from coconut husk: optimization study on removal of 2, 4, 6-trichlorophenol using response surface methodology, j. hazard. mater, 153, 709-717. 17. mui, e. l., ko, d. c., & mckay, g. (2004). production of active carbons from waste tyres––a review. carbon. 18. cleiton a. nunes; mário c. guerreiro 2011"estimation of surface area and pore volume of activated carbons by methylene blue and iodine numbers", quím. nova vol.34 no.3 são paulo. 19. edger t. f., himmelblau d. m, (2001), optimization of chemical process, 2nd ed, mcgraw-hill chemical engineering series. 20. foo. k. y. & hameed b. h. (2012). microwave-assisted preparation and adsorption performance of activated carbon from biodiesel industry solid reside: influence of operational parameters. bioresource technology, 103 (1), 398-404. 21. deng, h., li, g., yang, h. and tang, j. 2010a, “preparation of activated carbon from cotton stalk by microwave assisted koh and k2co3 activation”, chem. eng. j., 163, 373-381. 22. sudarynto, y., hartono, s. b., irawaty, w. and ismadji, s. 2006, “high surface area activated carbon prepared from cassava peel by chemical activation”, bioresour. technol., 97, 734-739. 23. d.w. mckee, (1983), mechanisms of the alkali metal catalyzed gasification of carbon, fuel, 62, 170-175. http://www.iasj.net/ available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.20 no.3 (september 2019) 67 – 73 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: ali h. alfattal, email: ali_alfattal@yahoo.com , name: ammar s. abbas, email: ammarabbas@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. synthesized 2nd generation zeolite as an acid-catalyst for esterification reaction ali h. alfattal and ammar s. abbas chemical engineering department-college of engineering-university of baghdad abstract mcm-48 zeolites have unique properties from the surfaces and structure point of view as it’s shown in the results ,and unique and very sensitive to be prepared, have been experimentally prepared and utilized as a second-generation/ acid catalyst for esterification reactions of oleic acid as a model oil for a free fatty acid source with ethanol. the characterization of the catalyst used in the reaction has been identified by various methods indicating the prepared mcm-48 is highly matching the profile of common commercial mcm-48 zeolite. the xrf results show domination of sio2 on the chemical structure with 99.1% and agreeable with the expected from mcm-48 for it's of silica-based, and the sem results show the cubic crystallographic space group compatible with ia3d space group giving the hexagonal surface structure. the afm test gave an average particle diameter of 97.51 nm and an average catalyst roughness of 0.855 nm. esterification reaction of oleic acid with ethanol on mcm-48 has been carried in a batch reactor with 5% the prepared mcm-48 zeolite catalyst loading gives 81% of conversion after one hour at 353k keywords: biodiesel, renewable energy, esterification, mcm-48 2 nd generation zeolite received on 21/10/2018, accepted on 27/04/2019, published on 30/09/1029 https://doi.org/10.31699/ijcpe.2019.3.9 1introduction the renewable fuels are growing progressively with time due to the limitation of conventional fossil fuel resources, increasing crude oil prices as well as concerns over environmental pollution and global warming ‎[1]. the energy security is a very complicated standalone science and practice but can be rather over simplified by the energy resources diversification. the energy requirements tend to increase the dependency on the renewable resources of energy, to promote the environmental protection and reduce greenhouse gas emissions. therefore, the energy security adoption led to the utilization of natural resources to generated energy that is from non-fossil bases (renewable energy), such as wind, solar, tidal, geothermal, and biomass derivative fuels ‎[2]. the biodiesel is a promising fuel that competing the regular fossil diesel commercially. the biodiesel produced from biomass oils and fats. depending on the value of the feedstock acid number, biodiesel might produce either through transesterification or esterification reaction. both homogeneous and heterogeneous catalysts commonly used in biodiesel production [2]. heterogeneous catalysis provides a better activation energy path, and eliminates catalyst spent problem, plus it can be easily utilized for low quality feedstock with less concerns of catalyst deactivation or poisoning if undertaking proper process operation and pre-treatment of the reactants provided to contain sufficient amount of free fatty acid ‎[2]. in esterification reaction the free fatty acid provides the hydroxyl group while the ethyl alcohol is the source of proton without an intermediate process ‎[3]. heterogenous catalysis differs from homogenous catalysis to undergoes a carbonium ion mechanism ‎[4]. heterogeneous catalysts are important for the development of biodiesel and have huge effect on the production cost. over the years different type of solid base catalyst has been investigated such as metal complexes ‎[5], ‎[6], metal hydroxides ‎[7], metal oxides such as calcium oxide ‎[8], magnesium oxide ‎[9], zirconium oxide ‎[10] and supported catalysts ‎[11]. solid catalysts are favorable over other catalyst type because they can be reused, regenerated and easily separated from product mixture. zeolites and microporous are types of solids catalyst that have being widely applied in catalysis, their smaller pore dimension limits their application for larger molecules. one of the zeolite types are the mcm family materials, they have an ordered mesopores ‎[12]. these materials have a well-defined pore. pore diameter can be varied in the range of approximately 20-100 å. https://doi.org/10.31699/ijcpe.2019.3.9 a. h. alfattal and a. s. abbas / iraqi journal of chemical and petroleum engineering 20,3 (2019) 67 73 86 the main materials in the m41s family are hexagonal (mcm-41) and cubic (mcm-48). both mcm-41 and mcm-48 have the potential to be used as catalyst in the esterification process. however, when comparing between mcm-41 with mcm-48, the mcm-48 provides easier access to guest molecules due to its threedimensional pore network. the structure of mcm-48 is cubic and has the space group ia3d ‎[13]. also, mesoporous materials have very high surface areas with regular pore size dimensions which make them a good support as active phases. the functionalization of these mesoporous materials by active acidic or basic moiety several contributions were made by various researches [11-14]. the shorter diffusion distances in mcm-48 arising from the pore structure may influence the distribution of the tethered group over the surface during the functionalization process ‎[14]. the work focused of the synthesis and characterization of a challenging new generation of zeolite mcm-48. study the performance of the prepared catalyst in esterification of oleic acid. 2experimental work 2.1. material 1liquid colloidal silica, ludox hs40 (39.5% sio,0.4%na2o, and 60.1%h2o by mass) as silica source 2hexadecyltrimethylammonium bromide htabr (aldrich) as surfactant 3industrial alcohol 90% etoh . 41.0 molarity of caustic soda solution naoh. 5washing hcl solution of 10% concentration by volume . 6distilled water h2o. 2.2. mcm-48 catalyst preparation colloidal silica (ludox hs40) preheated to 343 k in an erlenmeyer conical flask, then, the 1 m of caustic soda solution added slowly to the heated colloidal silica accompanied by vigorous magnetic continuous stirring (300 rpm). then, waiting likewise till the solution reached clarity after approximately an hour of continuous stirring accompanied by heating to stay in the temperature range of 343-353 k htabr (aldrich) was added to be dissolved completely till the solution becomes one phase by magnetic stirring and heating at 70 o c (343 k) with 100 ml of diluted ethanol (60 wt.%). after that, combining both the surfactant solution with the sodium silicate solution. placing the sol-gel in the autoclave with continuous stirring for 4 days and heated to 373 k. the supernatant liquid in the reaction mixture is cooled to 340 k and separated by vacuum filtration, the creamy solids on filter paper is washed with hot distilled water then with hcl-etoh, sent to dryer set on 100 o c (373 k) after proper filtration and then calcinated on an electric oven on 823 k aerobically. 2.3. esterification experimental setup the esterification reaction of oleic acid in batch reactor was undertaken in a batch laboratory scale reactor as shown in fig. 1. the assembly apparatus used for the experiment consists of 500 ml three neck flat bottom glass flask operating as a batch reactor for the experiment reaction and an electrical heater with various temperatures regulator that was calibrated and set specifically for the reaction mixture in hand, with magnetic stirrer arrangement to achieve a perfect contact among the reactants. the flask (batch reactor) was set in a manner that one side neck of it is plugged with air-tight rubber stopper that holds the thermometer used to enable monitoring the reaction temperature with the planned range of temperatures (40 to 70 c). the other side neck is used for tacking samples of the oil and alcohol catalyst mixture. the water-cooled condenser was inserted throughout the main neck of the reactor for purposes of the recovery of escaping ethanol that vaporizes at the elevated temperature during the reaction. fig. 1. schematic diagram of the batch reactor for esterification the required amount of catalyst (mcm-48) to be utilized in the experiment before each one was dried at 373 k for a period 2 h to eliminate any possible hydrate traces left on the surface of particles in inside the mesopores. at the beginning, the reactor was loaded with 50 ml (44.75 g) of oleic acid which was mixed with 6:1 ethanol to oil molar ratio. then the reaction mixture was heated to 343 k and finally 5 wt. % of the prepared mcm-48 zeolite was added to the mixture to initiate esterification reaction. a. h. alfattal and a. s. abbas / iraqi journal of chemical and petroleum engineering 20,3 (2019) 67 73 86 the small samples of the mixture inside if the reactor which consist from the reactants, products and catalyst were piped out from the left neck of the reactor and tested after each time interval (15 minutes), approximately 5 ml from the reaction mixture was withdrawn and centrifuged for a period of 10 min to make sure of the separation of the phases specially the particles of catalyst, and then a certain amount from the top layer of product was taken and then added 2 drops of phenolphthalein as indicator for free fatty acid and titrate with 0.1 molarity of koh in order to evaluate the acid value (av) as it was given by ‎[15]. (1) (2) 2.4. catalyst test and performance the characterization of the prepared catalyst was carried through different method of analysis a. x-ray diffraction (xrd) weight of sample is 3g in powder state, put in plastic cup 30 mm diameters. test conducted in inert atmosphere. the xrd test was done in geology science department – university of baghdad. x-ray diffraction test instrument 1using cukα radiation nickel filter (λ=1.54α). 2data were collected within the 2θ range of 1 o to 5 o with a 0.02 o 2θstep and 0.5s per step. 330 kv and 10ma x-ray diffraction was implemented to check the required patterns. b. bet surface analyzer test method according to astm d1993 for bet surface area and pore volume. the test reported by petroleum researchs and development center – ministry of oil. c. x-ray fluorescence (xrf) weight of sample is 3g in powder state, put in plastic cup 30 mm diameters. test conducted in inert atmosphere. the xrf test was done in geology science department – university of baghdad. d. scanning electron microscope (sem): done in chemistry science department – university of baghdad. e. atomic force microscope (afm): done in physics science department – university of al-nahreen 3results and discussion 3.1. characterization of prepared mcm-48 catalyst various techniques were undertaken in order to characterize the prepared second-generation acid zeolite, such as: x-ray diffraction (xrd), x-ray fluorescent techniques (xrf), scanning electron microscopy (sem), and atomic force microscopy (afm). a. xray diffraction (xrd) test result the xrd uses the diffraction pattern to reveal the crystal structure of the prepared zeolite in order to undertake phase identification between the prepared zeolite and a reference diffraction of the same type (standard mcm-48). fig. 2 shows the diffraction pattern of the prepared zeolite alone to be compared with the standard. the measurement was taken at angle range from 1 to 5.the measurements were taken under atmospheric conditions and the diffractometer was set with cu kα radiation (λ = 1.5406 a°). fig. 2. xrd pattern for the prepared mcm-48 zeolite the mcm-48 has only one peak in the x ray diffraction profile. this is true due to the fact that it compresses of one material only. the diffraction pattern of the prepared mcm-48 is approximately matched with standard by comparing the peak position and the angle. the peak position of the standard mcm-48 is located at 2θ= 2.281 o with max intensity of 949 [16], since the highest peak of the was located at 2.316, which are very closed with the highest peak in the reported data of mcm-48 zeolite ‎[16]. b. surface area and pore volume calculation the surface area and the pore volume of the prepared mcm-48 was measures using nitrogen adsorption and desorption method (bet). the measured value of the surface areas was 669 m 2 /g and the pore volume was 0.33 cm 3 /g. a. h. alfattal and a. s. abbas / iraqi journal of chemical and petroleum engineering 20,3 (2019) 67 73 07 c. xray florescence (xrf) analysis results the chemical constituents of the prepared mcm-48 zeolites were analyzed using xrf technique, it was important for chemical phase identification and to have a better view of the chemical structure. the chemical composition in weight percent is listed in the table 1. table 1. the xrf analysis results of chemical constituents for the prepared and mcm-48 zeolites oxides, al2o3 sio2 fe2o3 tio2 mgo k2o cao p2o5 other wt. % 0.0038 99.1 0.0014 1.06 0.0034 0.0012 0.128 0.71 9.033 the silicon oxide (sio2) was the dominant chemical structure with 99.1%. this is true because the mcm-48 is mainly silicon only and the xrf result is comparable with the xrd result in identify the prepared zeolite d. scanning electron microscope (sem) results the morphology of a sample from the prepared catalyst has been explored by using scanning electron microscopy (sem) image. the sem image was taken for 10µm, and 100µm respectively, as shown in images of fig. 3. the pattern is more obvious in the 10µm image indicates great structural order for cubic crystallographic space group compatible with ia3d space group giving the hexagonal surface structure of an mcm-48 zeolite mesophase structure. (a) (b) fig. 3. sem results for the prepared acidic mcm-48 zeolite e. atomic force microscopy (afm) technique results the study of topography of the prepared catalyst is accomplished by using atomic force microscopy (afm) device. a high-resolution image for the surface of the catalyst has been carried. the afm images can provide further information concerning the nature of the catalyst surface than the sem. average particle diameter was 97.51nm with which indicate that the prepared catalyst with in the nano scale preparation ‎[16]. fig. 4 shows the histogram distribution of the particle size of the prepared mcm-48. the afm show the accurate result of the average particle size which indicates the prepared zeolite is within the nano range. the particle distribution started from 40 with an average diameter of 97.51 nm ,10% of the distribution was for particles of 50 nm or less ,50% of the particles where 100 nm in diameter or less, and 90% of the sample were of 130 nm or less. the whole distribution occurs from 40 170 nm. topography image of the prepared zeolite is shown in fig. 5, and fig. 6 were both the 2d and 3d image were taken from the afm analysis. the characterization of the catalyst was the average roughness as shown in figure 6 was 0.855 nm. fig. 4. granularity cumulative distribution chart for prepared mcm-48 zeolite a. h. alfattal and a. s. abbas / iraqi journal of chemical and petroleum engineering 20,3 (2019) 67 73 07 fig. 5. 2d topography images for the prepared mcm-48 zeolite fig. 6. 3d topography images for the prepared mcm-48 zeolite f. effect of esterification temperature on oleic acid conversion esterification reaction of the model oil (oleic acid) with ethanol occurs in the liquid phase, effect of temperature for the esterification reaction has been studied with time as shown in table 2. temperature from 313-353 k has been studied and the experiment were operating for 60 min. with mcm-48 catalyst the oleic acid conversation increases with increasing temperature have been calculated by equation 2. when temperature increases at each run, the oleic acid conversion will also increase for acid value range from 40 to 82. when the temperature increases to 353 k, the oleic acid conversion increases double the increment value that has increased in the previous range after 60 min for all acid value. at 353 k, 81% of oleic acid is converted after 60 min which it’s the highest conversion reached in the experiment. table 2. conversions of different temperatures of operation vs. time of reaction using acid number as an indicator of the amount of oleic acid reacted temperature [k] acid number of oleic acid* conversion% 313 119.42 40.58 323 106.53 47.00 333 82.41 59.00 343 38.19 81.00 *initial measured acid number value for oleic acid was 200 the study of temperature effect on the esterification reaction is important to determine the proper reaction condition. also, according to arrhenius’s law the rate of reaction is temperature dependent. it’s important to keep the reaction in the liquid phase and no vaporization occurs. so the selected temperature were 313, 323, 333 and 343 k and all the reaction material are liquid in this range indicates the oleic acid conversion with time at different temperatures as listed in the table 2. the conversion of oleic acid at the minimum temperature of the experiment 313 k is about 40%, while the conversion of oleic acid at 353 k is about 81%. one way to explain this temperature effect of that phenomena is, when temperature increases the viscosity of the reactants decreases, thusly, that will lead to improve the reactants penetration or the passage of the molecule through the pores of the catalyst due to bulk viscosity reduction and as a result the reaction would be taken place rapidly at the active site of the catalyst. another way to explain it, or in addition to the above, is by increasing the temperature providing more molecules with sufficient energy to cross the modified-by-catalyst energy barrier of the reaction and convert accordingly. 4conclusion the mcm-48 catalyst has been successfully prepared as second-generation acid-zeolite utilized for an esterification reaction catalyst. the characterizations of the catalyst used in the reaction has been identified by various methods indicating the prepared mcm-48 is highly matching the profile of common commercial mcm-48, the xrd gave the peak of standards mcm-48 located at 2θ= 2.281 o with max intensity of 949, since the highest peak of the was located at 2.316, which are very closed with the highest peak in the reported data of mcm-48 zeolite. the xrf results show the domination if sio2 on the chemical structure with 99.1% and that’s agreeable with the expected from mcm-48 for its of silica based, and the sem results shows the cubic crystallographic space group compatible with ia3d space group giving the hexagonal surface structure. the afm test gave an average particle diameter of 97.51 nm, 10% of 50 nm or less, and 50% 100nm or less, the 3d topography gave average catalyst roughness of 0.855 nm. the esterification reaction has been carried using the mcm-48. a. h. alfattal and a. s. abbas / iraqi journal of chemical and petroleum engineering 20,3 (2019) 67 73 07 the effect of acid value was investigated after 60 minutes of esterification at the apparatus that was utilized as a batch reactor, gave that at 353 k, the highest conversion of 81% has been gained. references [1] ayhan demirbas, (2008) “biodeisel , a realistic fuel alternative for diesel engines” ,springer-verlag london limitted. [2] a.h.scragg ,(2009)“ biofuels, production application and development”, cambridge university press. [3] ammar s. abbas and rowaida n. abbas.(june 2015),” preparation and characterization of nay zeolite for biodiesel production”, (june 2015) ,iraqi journal of chemical and petroleum engineering ,vol.16 no.2, 1929 [4] mat, r., samsudin r.a., mohamed m., johari a. (2012), “solid catalysts and their application in biodiesel production”, vol.7 (2), 142 – 149. [5] abreu, f., lima, d., hamú, e., einloft, s., rubim, j. and suarez, p. (2003). new metal catalysts for soybean oil transesterification. journal of the american oil chemists' society, 80(6), pp.601-604. [6] dalai, a., kulkarni,, m. and meher, l. (2006). biodiesel productions from vegetableoils using heterogeneous catalysts and their applications as lubricity additives. ieeeeic climate change technology conference, eicccc art 4057358. [7] granados, m., poves, m., alonso, d., mariscal, r., galisteo, f., moreno-tost, r., santamaría, j. and fierro, j. (2007). biodiesel from sunflower oil by using activated calcium oxide. applied catalysis b: environmental, 73(3-4), pp.317326. [8] wang, l. and yang, j. (2007).transesterification of soybean oil with nano-mgo or notin supercritical and subcritical methanol. fuel, 86(3), pp.328-333. [9] georgogianni, k.g., katsoulidis, a.k., pomonis, p.j., manos, g., kontominas, m.g(2009)., “transesterification of rapeseed oil for the production of biodiesel using homogeneous and heterogeneous catalysis”. fuel process. technol. 90, 1016–1022. [10] ye, b., qiu, f., sun, c., li, y. and yang, d. (2013).biodiesel production from soybeanoil using heterogeneous solid base catalyst. j. chem. technol. biotechnol., 89(7) ,pp.988-997. [11] wu, s., han, y., zou, y., song, j., zhao, l., di, y., liu, s. and xiao, f. (2004). synthesis of heteroatom substituted sba-15 by the “phadjusting” method. chemistry of materials, 16(3), pp.486-492. [12] anton petushkov,(2001),” synthesis and characterization of nanocrystalline and mesoporous zeolites”, university of iowa, iowa research online. [13] soler-illia, g., sanchez, c., lebeau, b. and patarin, j. (2002). chemical strategies to design textured materials: from microporous and mesoporous oxides to nanonetworks and hierarchical structures. chemical reviews, 102(11), pp.40934138. [14] a. s. abbas, t. m. albayati, z. t. alismaeel, and a. m. doyle, “kinetics and mass transfer study of oleic acid esterification over prepared nanoporous hy zeolite”, ijcpe, vol. 17, no. 1, pp. 4760, mar. 2016. [15] dmytryshyn, s., dalai, a., chaudhari, s., mishra, h. and reaney, m. (2004). synthesisand characterization of vegetable oil derived esters: evaluation for their diesel additive properties.bioresource technology, 92(1), pp.55-64 [16] kim, ji man, and ryong ryoo. "synthesis of mcm-48 single crystals." chemical communications 2 (1998): 259-260. https://books.google.iq/books?hl=en&lr=&id=e2olekgwg3ec&oi=fnd&pg=pr5&dq=%5b2%5d%09a.h.scragg+,(2009)#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=e2olekgwg3ec&oi=fnd&pg=pr5&dq=%5b2%5d%09a.h.scragg+,(2009)#v=onepage&q&f=false https://www.iasj.net/iasj?func=article&aid=102642 https://www.iasj.net/iasj?func=article&aid=102642 https://www.iasj.net/iasj?func=article&aid=102642 https://www.iasj.net/iasj?func=article&aid=102642 https://www.iasj.net/iasj?func=article&aid=102642 https://www.researchgate.net/profile/ramli_mat2/publication/271303254_solid_catalysts_and_their_application_in_biodiesel_production/links/55b700e108aec0e5f4380284.pdf https://www.researchgate.net/profile/ramli_mat2/publication/271303254_solid_catalysts_and_their_application_in_biodiesel_production/links/55b700e108aec0e5f4380284.pdf https://www.researchgate.net/profile/ramli_mat2/publication/271303254_solid_catalysts_and_their_application_in_biodiesel_production/links/55b700e108aec0e5f4380284.pdf https://link.springer.com/article/10.1007/s11746-003-0745-6 https://link.springer.com/article/10.1007/s11746-003-0745-6 https://link.springer.com/article/10.1007/s11746-003-0745-6 https://link.springer.com/article/10.1007/s11746-003-0745-6 https://ieeexplore.ieee.org/abstract/document/4057358/ https://ieeexplore.ieee.org/abstract/document/4057358/ https://ieeexplore.ieee.org/abstract/document/4057358/ https://ieeexplore.ieee.org/abstract/document/4057358/ https://ieeexplore.ieee.org/abstract/document/4057358/ https://www.sciencedirect.com/science/article/pii/s0926337307000045 https://www.sciencedirect.com/science/article/pii/s0926337307000045 https://www.sciencedirect.com/science/article/pii/s0926337307000045 https://www.sciencedirect.com/science/article/pii/s0926337307000045 https://www.sciencedirect.com/science/article/pii/s0926337307000045 https://www.sciencedirect.com/science/article/pii/s0016236106002997 https://www.sciencedirect.com/science/article/pii/s0016236106002997 https://www.sciencedirect.com/science/article/pii/s0016236106002997 https://www.sciencedirect.com/science/article/pii/s0378382009000538 https://www.sciencedirect.com/science/article/pii/s0378382009000538 https://www.sciencedirect.com/science/article/pii/s0378382009000538 https://www.sciencedirect.com/science/article/pii/s0378382009000538 https://www.sciencedirect.com/science/article/pii/s0378382009000538 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.4190 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.4190 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.4190 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.4190 https://pubs.acs.org/doi/abs/10.1021/cm0343857 https://pubs.acs.org/doi/abs/10.1021/cm0343857 https://pubs.acs.org/doi/abs/10.1021/cm0343857 https://pubs.acs.org/doi/abs/10.1021/cm0343857 https://pubs.acs.org/doi/abs/10.1021/cm0343857 https://ir.uiowa.edu/etd/1057/ https://ir.uiowa.edu/etd/1057/ https://ir.uiowa.edu/etd/1057/ https://pubs.acs.org/doi/abs/10.1021/cr0200062 https://pubs.acs.org/doi/abs/10.1021/cr0200062 https://pubs.acs.org/doi/abs/10.1021/cr0200062 https://pubs.acs.org/doi/abs/10.1021/cr0200062 https://pubs.acs.org/doi/abs/10.1021/cr0200062 https://pubs.acs.org/doi/abs/10.1021/cr0200062 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/89 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/89 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/89 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/89 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/89 https://www.sciencedirect.com/science/article/pii/s096085240300213x https://www.sciencedirect.com/science/article/pii/s096085240300213x https://www.sciencedirect.com/science/article/pii/s096085240300213x https://www.sciencedirect.com/science/article/pii/s096085240300213x https://www.sciencedirect.com/science/article/pii/s096085240300213x https://pubs.rsc.org/en/content/articlelanding/1998/cc/a707677k/unauth#!divabstract https://pubs.rsc.org/en/content/articlelanding/1998/cc/a707677k/unauth#!divabstract https://pubs.rsc.org/en/content/articlelanding/1998/cc/a707677k/unauth#!divabstract a. h. alfattal and a. s. abbas / iraqi journal of chemical and petroleum engineering 20,3 (2019) 67 73 07 تصنيع جيل ثاني من الزيواليت كعامل حامضي مساعد لتحفيز تفاعل االسترة عمي حسين فتال و عمار صالح عباس جامعة بغدادقسم الهندسة الكيمياوية, كمية الهندسة, الخالصة بخصائص فريدة من حيث تركيب السطوح و البنية الجزيئية كما اظهرت mcm-48 تتميز مركبات الزيوليت النتائج ، اذ تم تحضيرها بشكل فريد و استخدامها كجيل ثاني من العوامل المساعدة لتحفيز تفاعل االسترة المحفز المستخدم في التفاعل بواسطة طرق متنوعة، أشار لحامض األوليك مع اإليثانول. تم تحديد خصائص المحضر يتطابق بشكل كبير مع الزيوليت التجاري من نوع mcm-48 فحص حيود االشعة السينية إلى أن mcm-48 و أظهرت فحوص تظهر نتائج xrf هيمنة لمادةsio2 9...عمى التركيبة الكيميائية و بنسبة إ و التي تعطي سطح سداسية ia3dب بموري مكعب متوافق مع مجموعة تركي sem ٪. كما و بينت نتائج سطح العامل المساعد خشونة ومتوسط نانومتر 5.79. الجسيم قطرمتوسط afm بناء. أعطى اختبار ٪ من العامل المساعد المحضر 7نانومتر. تم عمل تفاعل أسترة حمض األوليك مع اإليثانول بأستخدام 5.877 كمفن 373٪ بعد ساعة واحدة عند 81و وصل تحول حامض األوليك الى في مفاعل دفعي الكممات الدالة: الوقود احيوي, طاقة متجددة, االسترة iraqi journal of chemical and petroleum engineering vol.18 no.1 (march 2017) 111 120 issn: 1997-4884 the influence of eggshell particle sizes on the adsorption of organic dye besma mohammed fahad, nisreen sabah ai and tamarah t. hameed material engineering department, university of mustansiriya, baghdad, iraq abstract this work aimed to use effective, low-cost, available, and natural adsorbents like eggshells for removal of hazardous organic dye result from widely number of industries and study the influence of different eggshell particle size (75, 150) mm. the adsorbent was characterized by sem, edx, bet and ftir . the initial ph of dye solutions varying from 4 to 10 , the initial concentrations of methyl violet (mv) 2b range (20-80) mg/l, dosage range (0.5-10) g, contact time (30-180) min, and particles size of the adsorbent (75, 150) mm were selected to be studied. two adsorption isotherms models have been used to fit the experimental data. langmuir and freunlich models were found to more represent the experiments with high correlation coefficient. the results showed that the variation in particle size of eggshells powder statistically has slight effect on the removal of (mv). the highly percentage of dye removal (97.27%) by using eggshells was observed with particle size of 75mm, ph 4, at room temperatures for 30 min, 10 g adsorbent dose and 20 mg/l initial dye concentration. key words: eggshell, methyl violet, isotherm model, particle size, adsorption. introduction water contamination around the world has become serious environmental problem and it is either naturally or of man mad source, is produced by the addition of chemical, physical, biological materials in certain concentrations [1]. the contamination of wastewater in some industries such as dyestuff, textiles which can be difficult to treat leather, plastics, printing, etc. contain various kinds of synthetic dyestuffs [2]. and the main sources of wastewater are the dyeing and finishing processes [3]. as a result of extensive application , production of large-scale and synthetic dyes can be source undesirable pollution and many health-risk. due to the cancer-causing and mutagenic effects of synthetic dyes the presence even minor quantity colored wastewater is not only destructive the aesthetic nature of streams, also it can affect aquatic life and food webs [4, 5]. dyes chemicals, which on binding with a material will give color to them [6], are primarily have complex aromatic structures, which makes them biochemically stable [7]. its removal from wastewater carried out by either (biological or physicochemical) techniques. (e.g., adsorption, oxidation reduction, university of baghdad college of engineering iraqi journal of chemical and petroleum engineering the influence of eggshell particle sizes on the adsorption of organic dye 112 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net chemical coagulation, ozone treatment, and membrane filtration) [8, 9, 10]. adsorption technique is one of the most effective, low cost methods which is used for dye removal from wastewaters to produce high quality water [11]. nevertheless the usage of high cost adsorbents can be take in account as a restrictive factor [12, 13]. a variety of inexpensive and effective adsorbents of raw materials from unused to remove dyes have been used [14, 15]. eggshell, (agricultural waste) material from domestic sources such as hatcheries, poultry farms, egg product factories, homes and restaurant, it is a novel substrate, robust, cost effective and easily available [16]. as a by product characterizes nearly 11% of the complete egg weight is can be get rid of it as waste [17]. for the reason the vesicular structures and low cost can be used as a suitable adsorbent for contaminant removal [18, 19]. in addition to that porous nature makes it an attractive material to work as an adsorbent agent [20]. each one eggshell has been assessed to include between 7000-17000 pores [21]. with chemical composition of (94% calcium carbonate, 1% magnesium carbonate, 1% calcium phosphate and 4% organic material), [22]. therefore the main aim of this study was to investigate the effectiveness of eggshells powder for use as adsorbent material for removal of methyl violet (mv) 2b from aqueous solution which is widely used in industry and to determine the influence of the adsorbents of varying particle sizes on the adsorption of organic dye at most important factors which contain ph of the solution, initial dye concentration, the adsorbent dose, and contact time. materials and methods 1. chemicals in this study organic dye was used (mv) 2b with (mw= 393.96g/mol), melting point (mp) 137 °c, chemical formula c24h28n3c it was purchased from sigma aldrich company. hydrochloric acid (hcl, 37%). sodium hydroxide (naoh, 99%) was purchased from chemical bureaus in iraq. 2. eggshells eggshells were chosen to be an adsorbent which were collected from house & fast food restaurant. eggshells were washed thoroughly with distilled water to remove undesirable matters exist on eggshells surface. they were dried in an oven for 120 min at 105 °c and then that may crushed by suitable mill to prepare eggshells powder with different particle size (p.z) ranges (75-150) mm were obtained after using standard sieves. 3. stock solution preparation stock solution of mv dye was prepared by dissolving 1 g of mv in 1 liter of distilled water in conical flask. varying experimental concentrations of mv (2080 mg/l) were prepared via diluting with distilled water. 4. properties of adsorbents surface morphology of eggshells was obtained by scanning electron microscopy (sem, vega3 lmu tescan), eds is an analytical technique used to detect the chemical composition which forms an elemental analysis of the adsorbents and it is used in combination with sem. the adsorbents specific surface areas were intended using the brunauer – emmett -teller (bet) method, quantachrome.com, usa. information about the chemical bonds between molecules and the functional groups grafted onto the eggshells powder samples that provide using fourier transform-infrared spectra (ftir) spectroscopy is a technique which http://www.iasj.net/ besma mohammed fahad, nisreen sabah ai and tamarah t. hameed -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 113 were recorded by using instrument (ft-ir-600 ftir ,co.ltd.(uk)) spectrometer, model=(wqf) with (ac:220/50hz), at room temperature in transmission mode in the range of 4,000 to 600 cm −1 at 4 cm −1 resolution regions. 5. batch adsorption the experiments were done in 300 ml erlenmeyer flasks where 10 g of the adsorbent and 50 ml of the mb solutions (20–80 mg/l) be annexed. the ph of each solutions in interaction with adsorbents was found to be in the range of 4–10, and then the prepared solution agitated by using ultrasonic wave device for a predetermined time intervals and at room temperature. after agitating the samples were withdrawn from the device, to get rid from the present suspended adsorbent, the mixtures were filtered through filters papers. by using uvvisible spectrophotometer (uv-160 a shimadzu). final concentrations of (mv) were obtained. the percentages of dye removal or the amount of dye adsorbed were calculated from the following equation: 100 …(1) ( ) …(2) where r is the efficiency of dye removal, co, ce represent the initial and final dye concentrations, v is the volume of the solution and m is the mass of adsorbent. 6. effect of ph on dye adsorption to determine the effect of initial ph on adsorption of mv was tested over a range of ph values of (4-10) modified by, using 0.5 n hcl or 0.5 n naoh through keep other conditions fixed, the best ph attained use in next experiments. 7. effect of dye concentration this effect was determined by adjusted mv solution with varying concentrations range of (20-80 mg/l), use the best ph 4 that obtained from prior experiment and keep other conditions fixed. 8. effect of adsorbent dose two particle sizes (p.z) adsorbent dose of (75, 150) mm were selected to determine dose effect adding different weights of eggshell (0.5, 1, 3, 5, 7, 10) g to the best concentration 20 mg/l, ph 4 obtained from prior experiments for 3 hr. 9. effect of contact time on dye adsorption to detect this effect varying contact time range was adjusted (30, 60, 90, 120, 180) min, use the best conditions obtained from prior experiments. 10. adsorption isotherm adsorption is usually described through an isotherm showing in what way the adsorbed particles hand out between the liquid phase and the solid phase at what time the process of adsorption reaches balance state [23]. several models describe the process of adsorption from which langmuir and freundlich isotherm models can be exemplified respectively as follows [24]. kl (langmuir constant) were found by linearizing equation: …(3) the langmuir adsorption isotherm model is valid for monolayer adsorption onto a surface with a limited number of identical sites. the langmuir isotherm equation is the first theoretically developed adsorption isotherm and it's stay keeps an important location in physisorption in http://www.iasj.net/ the influence of eggshell particle sizes on the adsorption of organic dye 114 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net addition to chemisorption theories. the equation has also been derived using thermodynamic and statistical approaches. the equation of freundlich isotherm in linear form is as follows : …(4) where: kf and n: freundlich constants, if n between 2 and 10 it shows good adsorption. if numerical value of 1/n is fewer than 1 it refers that adsorption capacity is only slightly suppressed at lower equilibrium concentrations. the freundlich isotherm is more broadly used on the other hand provides no data on the monolayer adsorption capacity, in compare to the langmuir model. this model is depend on adsorption on inhomogeneous surface. it can be prophesied if an adsorption system is favourable or unfavourable by the necessary characteristic of the langmuir isotherm represented by means of rl, a dimensionless fixed referred to like separation factor or equilibrium parameter defined by 5: rl …(5) where co is the highest initial concentration. this parameter proposes the kind of isotherm to be irreversible (rl = 0), favourable (0 < rl < 1) or unfavourable (rl > 1). results and discussion 1. characterization of adsorbents scanning electron microscope observations of eggshell powder can be seen in figure 1. sem micrograph magnification factor is 1.00 kx which was taken to locate the micron eggshells powder. it can be seen that eggshells particles were agglomerated and have irregular round shape. however, the shape of particles was uniformly distributed. eds used together with sem which forms an elemental analysis of adsorbents powder include (ca,o, al) elements of different weight% (66.4, 33.2, 0.4) respectively as shown in figure 2. the adsorbents surface area was obtained by the (bet), test method (iso-9277-2010). the result show that the surface area decreased with increased partical size for (75, 150) mm patical sizes the surface area are (5.485±0.2, 4.656±0.37) m 2 /g respectively. fig. 1: sem image of eggshells powder at a magnification magnification=1.0000e3 http://www.iasj.net/ besma mohammed fahad, nisreen sabah ai and tamarah t. hameed -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 115 fig. 2: eds spectrum of eggshells powder figure 3 shown ft-ir analysis to eggshells powder. the peaks at 877, 2871, 2979 and 3070 cm −1 are referred to aromatic groups c-h bands. as well, it appears that a prominent absorption peak of carbonate c-c bands was observed at 1429 cm -1 , attributed to aromatic group. the peaks at 1078 cm −1 is assigned to alcohols,carboxylic acids,esters,ethers groups c-o bands and finely the bandat 3286 cm -1 is because of the existence of strong hydrogen-bonding alcohols,phenols groups with surface oh groups interactions between them. fig. 3: ftir analysis for eggshells powder 2. adsorption results 2.1. effect of ph as shown in figure 4. the ph solution effects on the process of adsorption of (mv) dye was obtained, by using eggshell as adsorbent with two particle sizes (75, 150) mm. these results revealed as ph value increases the percentages of dye removal decreased slightly. greater percentages of mv removal were noticed (97.7%, 97.3%, 97.1%, 96.7%) for eggshell of 75 mm particle size and (97.8%, 97.8%, 97.1%, 97.1%, 96.7) for eggshell of http://www.iasj.net/ the influence of eggshell particle sizes on the adsorption of organic dye 116 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net 150 mm particle size respectively, at ph range of (4, 6, 8, 10). these attained results may be ascribed to the surface of adsorbent becomes negatively charged and does not prefer dye adsorption as a result of the electrostatic repulsion [25]. from these results found that maximum removal efficiency occurs at ph = 4 for both particle size. fig. 4: effect of ph solution on (mv) removal 2.2. effect of initial dye concentration the effects of dye concentration on removal efficiency of (mv) dye by eggshell powder is shown in figure 5. with ph fixed at 4. the results show that with increasing the initial dye concentration from 20 to 40 mg/l for 75 mm particle size, the removal efficiency was decreased slightly from 98.4% to 98.3% and then reached equilibrium, further increase in dye concentration have no effect. this slight effect associated with increase dye concentration is attributed to the vacant sites on the eggshell surface in higher dye concentrations become saturation [26], for 150 mm particle size the removal efficiency was increased from 91.9% to 98.3% as the dye concentration increased 20 to 60 mg/l and then reached equilibrium. fig. 5: effect of concentration on (mv) removal 2.3. effect adsorbents dose as shown in figure 6 (mv) dye removal via eggshell powder at different adsorbent weight (0.5-10 g), dye concentrations of 20 mg/l and ph 4. the results show for adsorbent of 75 96.6 96.8 97 97.2 97.4 97.6 97.8 98 0 5 10 15 r e m o v a l % ph p.z 75 μm p.z 150μm 50 55 60 65 70 75 80 85 90 95 100 0 20 40 60 80 100 r e m o v a l % concentration(mg/l) p.z75μm p.z150μm http://www.iasj.net/ besma mohammed fahad, nisreen sabah ai and tamarah t. hameed -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 117 mm particle size the increase in dose up to weight of 5 g lead to increase the percentages of dye removal efficiency in the range of (86%, 93.5%, 95.3%, 96.5%, 96.5%, 98.9%) and then reached equilibrium as a result of saturation available active site. for adsorbent of 150 mm particle size the removal efficiency increase gradually in the range of (78.9%, 85.6%, 92.1%, 93.9%, 95.6, 98.3%) as adsorbent dose increase at 0.5, 1, 3, 5, 7, 10 g respectively, this higher removal of (mv) is due to the increase in adsorbent surface and availability of more adsorption site area of the adsorbent. therefore the quantity of dye adsorbs increases and therefore leads to a well adsorption [25]. the results show that the best removal occur at 10 g is 98.9% for 75 mm particle size which will used in the following the experiments. fig. 6: effect of dose on (mv) removal 2.4. effect of contact time as shown in figure 7 contact time effects onto the removal efficiency of (mv) dye, which is taken in the range of 30-180 min. the results show that the removal percentage was rapid at initial time and reached the best efficiency (97.2%, 96.1%) with first 30 min and then increased slightly for particle size of 75 and 150 mm respectively. the equilibrium was attained at 120 min for both adsorbent particle size. from thesse results found different eggshells partical size has slit effect on dye removal [25]. fig. 7: effect of contact time on (mv) removal 50 55 60 65 70 75 80 85 90 95 100 0 2 4 6 8 10 12 r e m o v a l % dose(g) p.z 75μm p.z 150 μm 50 55 60 65 70 75 80 85 90 95 100 0 50 100 150 200 r e m o v a l % time (min) p.z 75μm p.z 150μm http://www.iasj.net/ the influence of eggshell particle sizes on the adsorption of organic dye 118 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net 2.5. adsorption isotherm as shown in figures 8 and 9 the exemplary schematic representations of the linearized plots for adsorption of methyl violet on eggshell. the results show that the adsorption isotherms experimental equilibrium data (table 1) were fitted to both the freundlich and langmuir isotherm equations and it show good fitting with the highest correlation coefficient values r 2 (0.93, 0.99) respectively for adsorbent with particle size of 75 mm. for adsorbent with particle size of 150 mm langmuir isotherm with r 2 0.86 a better representation of the experimental results than freundlich isotherm with lower r 2 0.45. as well langmuir model was found to provide a well fit in the adsorption of mv for both adsorbent particle sizes. this well fit of equilibrium information to the langmuir isotherm propose monolayer coverage of mv on the eggshell with 75, 150 mm particle size and the surface of egg shell is known to be homogenous [27]. it can be seen from table 1, the value of rl is less 1 in both in both particle sizes which suggests that the adsorption is favourable. table 1: isotherm constants for mv removal by eggshell freundlich isotherm langmuir isotherm p.z (μm) kf n r 2 rl r 2 kl al 75 0.69 0.54 0.93 0.032 0.992 0.373 0.405 150 0.95 1.46 0.405 0.0099 0.869 1.24 0.15 fig. 8: langmuir adsorption isotherm model fig. 9: freundlich adsorption isotherm model y = 1.0878x + 2.6743 r² = 0.992 y = 7.1321x 4.9153 r² = 0.869 -4 -2 0 2 4 6 8 10 12 14 0 0.5 1 1.5 2 2.5 c e /q ₑ( m g /l ) cₑ(mg/l) p.z 75μm p.z150μm y = 1.84x 0.1585 r² = 0.9371 y = -0.5949x 0.4528 r² = 0.4055 -1.2 -1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 -0.6 -0.4 -0.2 0 0.2 0.4 lo g q ₑ (m g /g ) log cₑ (mg/l) p.z 75 p.z150 http://www.iasj.net/ besma mohammed fahad, nisreen sabah ai and tamarah t. hameed -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 119 conclusions this study is concentrated on the using eggshells for removal of mv from aqueous solution as a cheap, alternative adsorbent, provide high removal efficiency with short time 30 min and environmental concerns. furthermore eggshells has superior efficiency to remove the organic dye by adsorption process as a function of many conditions such as (ph, initial dye concentration, adsorbent dosage, contact time and particle size). process of adsorption basically based on the adsorbent particle size of the, the small particle size the greater surface area, the capacity of adsorption rises. the high percentage of removal for 75 mm particle size is better than 150 mm particle size at ph 4, 10 g adsorbent dose, 30 min and 20 mg/l initial dye concentration. references 1. metcalf, e., tchobanolgou,g. franklin, b., and stensel, h. d. (2003). “wastewater engineering: treatment and reuse”, 4 th ed., mcgraw-hill, new york. 2. chiou, m.s., li, h.y., j. (2003), “adsorption behavior of reactive dye in aqueous solution on chemical cross-linked chitosan beads. chemosphere. 50 (8): 1095-1105. 3. amran, m.b. and zulfikar, m.a., (2010), “removal of congo red dye by adsorption onto phyrophyllit”, international journal of environmental studies, 67 (6), 911-921. 4. crini, g., (2006), ''nonconventional low-cost adsorbents for dye removal: a review'', bioresource technology, 97, 10611085. 5. chatterjee, s., lee, d.s., lee, m.w. and woo, s.h., (2009), “enhance adsorption of congo red from aqueous solutions by chitosan hydrogel beads impregnated with cetyl trimethyl ammonium bromide”, bioresource technology, 100, 2803-2809. 6. shaobin wang., boyjoo, y., choueib, a., zhu, z.h., (2009), “removal of dyes from aqueous solution using fly ash and red mud.” water research, 2005, 39 (1), 129138. 7. aksu, z., tezer, s., (2005)., “biosorption of reactive dyes on the green alga chlorella vulgaris”, process biochemistry 40 (3–4), 1347–1361. 8. mckay, g., (1996), “use of adsorbents for the removal of pollutants from wastewaters”, crc press, boca raton. 186 p. 9. zheng, y.-m., q.-b. zhao and h.q. yu., (2005), “adsorption of a cationic dye onto aerobic granules”, proc. biochem. 40: 3777-3782. 10. valix, m., w.h. cheung and g. mckay, (2004), “preparation of activated carbon using low temperature carbonisation and physical activation of high ash raw bagasse for acid dye adsorption”. chemosphere 56: 493 501. 11. sarioglu, m. and u.a. atay, (2006), “removal of methylene blue by using biosolid”. global nest j., 8: 113-120. 12. samarghandi mr, azizian s, samadi mt, shokoohi r, rahmani a, (2011), “using thomas model to evaluate dye removal from aqueous solutions in fixed-bed columns of activated carbon”. journal of water and wastewater; 22 (77): 23-34. [in persian]. 13. bazrafshan e, kord mostafapour f. evaluation of color removal of methylene blue from aqueous solutions using plant stem. 14. annadurai, g., juang, r.s., and lee d.j., (2002). "use of cellulosebased waste for adsorption of dyes from aqueous solutions". journal of hazardous materials b92: 263-274. http://www.iasj.net/ the influence of eggshell particle sizes on the adsorption of organic dye 120 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net 15. ozer d., dursun g.and ozer a., (2007). "methylene blue adsorption from aqueous solution by dehydrated peanut hull". journal of hazardous materials 144: 171-179. 16. amu, o.o., a.b. fajobi and b.o. oke, (2005), “effect of eggshell powder on the stabilization potential of lime on an expansive clay soil”, res. j. agric and biol. sci., 1: 80-84. 17. pramanpol, n. and n. nitayapat, (2006), “adsorption of reactive dye by eggshell and its membrane”. kasetsat j.: nat. sci., 40: 192-197. 18. abramian l, el-rassy h, (2009), “adsorption kinetics and thermodynamics of azo-dye orange ii onto highly porous titania aerogel”. chemical engineering journal; 150 (2-3): 403-10. 19. ghaneian m, ehrampoush m, ghanizadeh g, momtaz m, (2011), “study of eggshell performance as a natural sorbent for the removal of reactive red 198 dye from aqueous solution”. j toloo e behdasht; 10 (1): 70-81. [in persian]. 20. ghanizadeh gh, asgari gh.,(2009), “removal of methylene blue dye from synthetic wastewater with bone char”, iranian journal of health and environment; 2 (2): 10413. [in persian]. 21. william, j.s. and j.c. owen, (1995), “egg science and technology. 4 th edn. food product press”, new york, pp: 950. 22. tsai wt, et al., (2006), “characterization and adsorption properties of eggshells and eggshell membrane”, bioresource technology; 79: 488 493. 23. nwabanne, j. t. and p.k. igbokwe, (2008), “kinetics and equilibrium modeling of nickel adsorption by cassava peel.” j. of engineering and applied sciences, 3 (11): 829-834. 24. farah, j.y., el-gendy, n.s., farahat, l.a., (2007),. “biosorption of astrazone blue basic dye from an aqueous solution using dried biomass of baker’s yeast”. j. hazard mater, 148 (1-2): 402-408. 25. muhammad ali zulfikar and henry setiyanto, (2013), “adsorption of congo red from aqueous solution using powdered eggshell”, international journal of chemtech research, vol.5, no.4, pp 532-1540. 26. aravindhan, r., fathima, n.n., rao, j.r. and nair, b.u., (2007), “equilibrium and thermodynamic studies on the removal of basic black dye using calcium alginate beads”, colloids and surface a, 299, 232-238. 27. uddin, m.t., m.s. islam and m.z. abedin, (2007), “adsorption of phenol from aqueous solution by water hyacinth ash.” arpn j of engineering and applied sciences, 2 (2): 121-128. http://www.iasj.net/ available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.23 no.1 (march 2022) 43 – 50 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: tariq m. naife, email: tariq.mohammed@coeng.uobaghdad.edu.iq, name: sarmad a. rashid, email: sermed.rashid@coeng.uobaghdad.edu.iq , name: marwa f. abdul jabbar, email: marwa84_2007@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. treatment of used lubricant oil by solvent extraction tariq m. naife a , sarmad a. rashid a and marwa f. abdul jabbar b a university of baghdad, chemical engineering department, baghdad, iraq b al-nahrain university, chemical engineering department, baghdad, iraq abstract this study investigates the treatment of used lubricating oils from al-mussaib gas power station company-iraq, which was treated with different extractive solvents (heptane and 2-propanol). the performance activity of these solvents in the extraction process was examined and evaluated experimentally. operating parameters were solvent to oil ratios of (1:2, 1:4, 1:6, and 1:8), mixing time (20, 35, 50, and 65 min), temperatures (30, 40, 50, and 60 ºc), and mixing speed (500 rpm). these parameters were studied and analyzed. the quality is determined by the measuring and assessment of important characteristics specially viscosity, viscosity index, specific gravity, pour point, flash point, and ash content. the results confirm that the solvent 2-propanol gave great proficiency with the most elevated percent of sludge removal compared with heptane. the greatest percentage of waste removal is enhanced when the solvent/oil ratio increases with optimal economic aspects. the significant characteristics of the reused lubricating oil were estimated. the outcome of the results indicates that the adjustment of the characteristics of reused oil has great effectiveness and the best working conditions for 2-propanol (35 min, 1:6 s/o ratio, 40 ºc), and heptane (50 min, 1:6 s/o ratio, 50 ºc). keywords: used lubricating oil, characteristics of lubricating oil, and solvent extraction. received on 07/03/2022, accepted on 28/03/2022, published on 30/03/2022 https://doi.org/10.31699/ijcpe.2022.1.6 1introduction the principal functions of lubricants are to work on the perfection of the smoothness of contact and movement parts from one surface to another and thus reduce the friction between these surfaces, as well as decrease the contact friction of the various parts of machine or engine, retain heat, deny corrosion, and deter contamination. as a result, a thin lubricant film between the contact surfaces prevents wear and reduces power loss [1, 2]. in working, the lubricant oil loses its efficiency gradually and degrades with time. the percent of this degradation depends on several factors, such as the environment, the quality of the lubricant, and operating conditions. however, the engine oil has reached a point that will no longer time to be able for performing its functions with good performance [3,4], so, at this point, this oil must be changed and replaced from the engine because of losses in efficiency and stress from real deterioration in service [5]. one of the public's most used methods of disposal is used in many sectors such as vehicles, industries, and the production of electricity for different functions such as minimizing friction between moving parts that contact each other, heat dispersion, the transmission of power [6,7]. used lubricating oils, which are hard to handle anthropogenic poisons or pollutants because of their poisonousness and have become unwanted for use. the reusing of waste oil might be a fitting and modest option in contrast to incineration [8]. for economic reasons, the convenient substitutional to incinerate used oil by recycling. the necessity for the recycling of utilized lubricant oil for conceivable reuse has appeared because of attention to the environment, industrial lubricant stability, as well as a growing reliance on this product for industrial purposes [9,10]. the amount measured of used lubricating oil in iraq that is used annually is exceptionally enormous. this enormous amount of utilized engine and power generation oil fundamentally affects both economic and environmental aspects, in many cases the cost a lot of money/birr to make and are a rising toxin and pollution substance when rejected. whenever released these pollutants are into the land, ecosystem, water, or even consumed as poor quality oil [11]. there are several reuse methods have been proposed for the treatment of used lubricant oils. a suggested solution to this study is the recapture functionating of the lubricant base oil depending on the used oil [12]. treating methods for using lubricating oil with solvents that are nonpoisonous and cost-effective is the ideal solution [13]. various methods have been created and developed that can be used for the processing of used mobile and total lubricant oil samples to enhance their specifications and quality for reuse, like that waste oils, have also been rerefined to base oil utilizing a process known as hydrotreating or hydro finishing [14]. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:tariq.mohammed@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2022.1.6 t. m. naife et al. / iraqi journal of chemical and petroleum engineering 23,1 (2022) 43 50 44 reusing used lubricant oil can either reestablish the base use of the lubricant oil or eliminate the pollutants to the extent that it can be turned into a convenient medium for subsequent use. solvent extraction is one of the most compelling processes for the recycling of waste lubricant oil [15-20]. there are plans to recover the lubricating oil to conserve natural local resources. these are the most appealing recycling technologies in general. the solvents choices ought to have the greatest solubility for virgin oil and the least amount of additive carbonaceous. the solvents then can be recovered by refining for recycling purposes [9]. solvent refining by extraction is dependent on the properties of the original stock. furthermore, because of different service periods, the chemical composition of used lubricating oil fluctuates and is complicated to characterize, besides the solvent type and concentration employed [21]. this study's main commitment is to minimize the percentage of oil misfortunes by using suitable solvent extraction. various variables, such as solvent/oil ratio, extraction conditions, and kinds of solvents, are also examined. refine the used lubricating oil and recycle using a solvent extraction treatment procedure, as well as compare the solvent efficiency for reused or mixed into lubricating products, reducing the use of virgin oil. this study is exceptionally huge for our country since it settles and solves environmental problems due to using lubricating oil from gas power stations in all countries. 2experimental work 2.1. materials a. lubricating oils, both fresh and used fresh and utilized lubricating oil (mobil jet oil) was obtained and collected from al-mussaib gas power station company (ministry of electricity-iraq) and applied to an electrical power generator of 400 kva type by perkin company for about 72 hours. the lubricating oils were emptied of gathered from the generator of electric power for treatment and examination, analyzing the properties of both fresh and used table 1. table 1. specifications for both fresh and used lubricating oil characteristics fresh generator oil used generator oil specific gravity at 15°c/15°c 1.0035 1.1052 viscosity at 40°c ,cst 27.6 48.7 viscosity at 100°c ,cst 5.1 9.1 viscosity index 107.43 111 flash point , °c 292 268 pour point ,°c -43 -54 ash content ,wt% 0.00 1.174 water content, ppm 31 52 carbon residue, wt% 1.56 0.02 b. solvents there are two types of solvents used in this study 2propanol (sigma-aldrich) and heptane (hopkin & willams ind.), all with a purity of 99% were analytical grade. 2.2. extraction experiments a. pre-treatment this step is very important and is required at the beginning of the process. the first treatment involves removing suspended solids from used lubricant oil, which are separated after mixing by a homogenizer and allowed to settle down. after that, the sample was collected and filtered under vacuum pressure (5 mm hg) for the disposal of suspended solids. b. dehydration the dehydration step is very necessary for removing a little bit of water which is restricted to working out under normal engine operating conditions, mainly because of air entry. for dehydration step, put a suitable amount of the used lubricating oil in the lower part of the flask, the used oil was permitted to settle down for 24 hours, as a result, simple decantation of the thick aqueous phase with its associated contaminants is possible. this step was carried out with an atmospheric distillation system to a temperature of 125 °c, this temperature was chosen to be confident that all water be evaporated for the reason that. this process continues till no distillate was received. the unit of distillation consists of a heating source with a 500 ml capacity, 220v 50/60hz, 320w, and a 500 ml pyrex flask joined to a condenser. the condenser has two holes for water flow that is supplied for cooling from a water tap, joined to the inclined neck, and the second neck is joined to the thermometer at a maximum range of 250 o c. put the flask below the condenser as a reservoir, with a 250 ml flask as the volumetric flask [22]. c. removal of light cuts the conceivable elimination of light ends in feedstock energy is conceivable with the utilization of a basic batch vacuum distillation setup that worked at a temperature of 220 °c and a vacuum pressure of 5 mm hg. the vacuum distillation step was done for about 60 min, this time is enough to remove light cuts. d. solvent extraction a laboratory batch extraction unit was used for the contacting step. varying the solvent-to-oil ratios (1:2, 1:4, 1:6, and 1:8), temperatures (30, 40, 50, and 60 °c), mixing times (20, 35, 50, and 65 minutes), and mixing speeds (500 rpm) the mixture is left for 3 hours to separate as mentioned in literature [21,22]. t. m. naife et al. / iraqi journal of chemical and petroleum engineering 23,1 (2022) 43 50 45 after a steady-state is demonstrated by a steady level, the two phases are separated by utilizing a separating funnel. when the blended mixture separates into two layers (raffinate and separate), so, used an effective solvent. the virgin oil is extracted from the used oil using a solvent, while contaminants are separated, settled down, and withdrawn. the bottom layer represents impurities and precipitates, while the upper layer is filtered and then the solvent is vaporized. the effects of these solvents on properties were examined and evaluated. e. solvent recovery the solvent was stripped from the raffinate solution by distillation under a vacuum of about 5 mm hg to avoid decomposition, and from the extract solution by atmospheric distillation. the raffinate and extract solutions were heated in the flask using a heating mantle with a regulator to control the heat supply as shown in fig. 1. the stripped raffinate was weighted and the raffinate yield was obtained. fig. 1. laboratory distillation unit 2.3. test methods a. specific gravity the specific gravity was estimated by the astm d94155 method by the hydrometer device which was used for density measurement of the material to the density of the equal volume of water. the density was measured and recorded at standard conditions (15 ºc). b. viscosity the viscosity of lubricating oil was estimated by the astm-d445 method. c. viscosity index the viscosity indexes of lube oil distillate fraction and raffinate oil were determined by the astm-d2270 method. d. ash content ash content has been tested (astm d482-03). after a cooling step, they used sulphuric acid to process the ash content (sulphated ash), and then the ash was warmed to 780 o c. at this degree, a constant mass was obtained. ash remained weighted in the final stage. e. flash point for flash point measurement by the astmd92 method, 5 cm 3 of lubricant oil was transported into a 50 ml measuring flask, and then a temperature measurement by thermometer was embedded. the heating source, an abunsen burner, was placed beneath the flask. at specific times, to set the temperature, a flame was operated. then a flash will appear on the face of the oil being tested at a specific temperature while the sample of oil is being heated in the flask. f. pour point the pour point was measured by the astm d97 method. 25 cm 3 of the lubricant oil was placed in a vessel. the lubricating oil was placed in a cooling bath medium, and a specific paraffin wax crystal was formed. if the oil sample does not flow when inclined, it is held horizontally in the container for 4–5 seconds to witness the movement of the surface sample. continuous chilling was done till the sample stopped flowing. at this point, the temperature had reached a "pour point temperature." 3results and discussion 3.1. specific gravity specific gravity is very impacted by the chemical constituent of the lubricating oil. the value of the specific gravity of used lubricating oil is much more than that of the virgin oil and the treated oil, this may be due to an increase in the quantity of the aromatic compound in the oil sample or high solids content present in the used engine oil, which led to the specific gravity is increased, while when saturated compounds increased, a decrease in the specific gravity was observed [23]. as shown in table 2, the values of specific gravity for virgin oil are 1.0035, and this value is low compared with the value of used lubricating oil which is 1.1052. the rising value of specific gravity for utilized lubricating oil is because of the existence of contaminations such as solids, metals, or oxidation products. the efficiency for both solvents is closed to the specific gravity. the specific gravity of 2-propanol solvent is more efficient than heptane on oil’s specific gravity, resulting from treatment by the ratio (1:6) (1.063), which is very acceptable as closed to the specific gravity of virgin oil (1.0035), which means low contaminations and metals. t. m. naife et al. / iraqi journal of chemical and petroleum engineering 23,1 (2022) 43 50 46 table 2. physical characteristics of treated lubricating oil no. solvent type solvent / utilized oil viscosity @40 ºc (cst) viscosity @100 ºc (cst) viscosity indexvi specific gravity 1 heptane 1:2 42.8 8.7 110.163 1.101 2 heptane 1:4 39.7 7.9 109.843 1.081 3 heptane 1:6 37.3 6.3 107.779 1.069 4 heptane 1:8 33.9 5.8 107.599 1.095 5 2-propanol 1:2 40.9 9.5 109.573 1.102 6 2-propanol 1:4 37.6 9.2 108.564 1.087 7 2-propanol 1:6 34.4 7.9 107.496 1.063 8 2-propanol 1:8 33.3 7.1 107.501 1.091 3.2 viscosity viscosity is a very important consideration in the characteristics of fluids and lubricating oils. it’s classified as a state function and depended on temperature, pressure, and density. the relationship between viscosity and temperature is an inverse connection, so, when the temperature of the lubricating oil decreases, the viscosity increases, and vice versa. the friction between layers, or the oil film strength, is just about congruous to its viscosity. so, when rising the value of the viscosity, means the stronger the lubricating oil film. raising or lowering in values of viscosity can happen because of the presence of contamination compounds, oxidation, or insoluble fuel [24]. commonly, the higher viscosity of diesel engine oil compared with the gasoline engine is due to the light compound in gasoline engine oil, several problems might arise in working, like that heat generation from inner liquid friction, and definitely, the heat is influenced to the life of oil [25]. the results of viscosity show that the increases in values of used lubricating oil, because of polymerized compound oxidized products which dissolved and suspended in the oil, the high value in viscosity indicates the presence of pollutants. the oxidation of working oils is increased dramatically and generates produce deposits of corrosive oxidized products leading to increased viscosity [26]. for different solvents, the viscosity with four s/o ratios is shown in table 2. viscosity at 40 °c was affected by heptane, and there was an improvement in viscosity characteristics, with the best value at a (1:8) ratio (33.9 cst). a similar outcome was predicted at 100 °c (5.8 cst). however, while the viscosity of the treated oil was more significantly impacted by the 2-propanol solvent at 40 °c (33.3 cst), and also at 100 °c the value was (7.1 cst). this is a result of pollutants and degraded materials. at the point when the treated oil is seen, there is a contrast between the utilized, treated, and virgin oil. the viscosity of lubricating treated oil, for example at the ratio 1:2 in table 2, the viscosity is 42.8 cst with heptane and 40.9 cst with 2-propanol at 40 °c. this means the two methods are degraded materials and impurities are removed and effective in eliminating or eliminating the oxidized products and deposits from the utilized oil [27]. this may likewise mean eliminating the added substances that have been added to upgrade viscosity. 3.3. viscosity index the viscosity index is an experimental value, and it is the most important property of lubricating oil that reflects the range of the effect of the viscosity of lubricating oil upon the temperature change. a high viscosity index lubricating oil is preferred because it has excellent lubrication efficiency and low consumption when in use, as opposed to low viscosity index oil [28]. a rise in viscosity index demonstrates a little variation in viscosity with temperature, which additionally implies a good assurance of an engine that works with tremendous temperature varieties. improvers in viscosity index are between the normally added substances that enhance oil efficiency. a high value in viscosity index is because of a shortfall of volatile and aromatic compounds. it additionally implies and low-temperature flow behavior and great thermal stability [29]. both solvents in table 2 have fundamentally the same effectiveness when added to the used oil for both solvents on the viscosity index. table 2 indicates that for the treated utilized oil, the viscosity index with heptane 107.599 at the ratio of 1:8 veered off marginally from that of the utilized oil, 107.43. this shows the least negative impact 2-propanol has on the viscosity index enhancing added substances. it likewise appears to be that the two solvents added to a decrease in the viscosity index that was measured. 3.4. the flash point the flash point is characterized by engine oil and it indicates the most minimal temperature of the oil which should be warmed to give off adequate vapor, forming a mixture with air that ignites immediately by a particular flame under indicated conditions. the purity of the engine oil and the percent of oil contamination indicate the flash point. a considerably, so, the lowest value of flash point in engine oil is a credible point that the contaminated oil has become volatile with products such as gasoline. due to the increased molecular mass of the oil, this is led to an increase in flash point. the arrangement of volatile components as a result of oxidation would prompt a decay in the flash point [30]. fig. 2, shows the flash point values of two solvents at a law solvent/oil ratio, shows a diminishing in flash point values in comparison with the fresh or at high ratios. t. m. naife et al. / iraqi journal of chemical and petroleum engineering 23,1 (2022) 43 50 47 different additives show improving its flash point 292 °c, which contribute with fresh oil to enhance the flash point. surprisingly, the flash point measured on the oil sample is 268 °c. this flash point reduction is a consequence of contamination with oxidizing products. on the other, the flash point of the fresh oil clearly shows that is exceptionally impacted by 2-propanol as shown in the figure. then again, it is somewhat less impacted by adding heptane and 2-propanol, which elucidate the negative and complex impact of 2-propanol even on base oil. the flash point of the fresh oil is raised by utilizing heptane treatment [31]. that implies there is fuel contamination in the oil. also, at the high temperature, it very well may be because of the existence of light cuts in oil while going through burning and oxidation in the burning engine. during that process, the oil is destructive into ingredient parts, which incorporate several light ends [32]. fig. 2. the effect of the solvent to oil ratio on each solvent's flash point 3.5. pouring point the most important characteristic of lubricating oil is pour point of engine oil, which is indicated to stay in a streaming state at the lowest temperature, in generality engine, virgin oils contain paraffin and waxes that thicken at low temperatures. high paraffin and wax content in engine oils led to an elevated pour point. the oil’s viscosity is very affected on pour point, and at high viscosity. the engine oil pour points are described by their high pour points. it was identified as a significant variable, particularly when cold weather turns over the engine. even at low temperatures, the oil should stream through the pump of oil and then be pushed out to the other engine parts [33, 34]. fig. 3 shows the pour point values of two solvents. base oil pour point was not significantly affected by the addition of heptane. at first, the pour point changed by about 1.2 degrees celsius, when 2-propanol was added, the temperature rose to 3.5 °c, the result of heptane additives to the oil solvent is necessary before the oil. fig. 3 shows the high effect of the (s/o) solvent to oil ratio on the pour point of solvents for used generator oil. this is a result of the declination of additives in lubricant oil. pour point, specifically, is significant when oil should be put away in generally cool conditions [35]. the point changes broadly depending on the base oil and its sources, and the refining technique, particularly if at the end or finishing dewaxing [14]. when working lubricant oils are used with time, the aliphatic chains attached to the aromatic compound's ring are cracked and separated as a result of oxidation [36]. as shown in fig. 3, the pour point of treated oils decreases as the solvent to oil ratio increases. fig. 3. the effect of the solvent to oil ratio on each solvent's pour point 3.6. ash content from figure 4, it was found that 2-propanol was the most suitable for solvent extraction. ash content is the content of the material non-organic mineralization in oil. the ash content of utilized oil is high (1,174) as a result of the presence of minerals. its sources are different, such as pollution, rust, and rust metals, which are produced by friction or corrosion of the engine conductors during operation, such as pistons, cushions, etc., or may result from dirt leaks or additive residues. with this deduction, the ash value decreased to 0.029% at a high ratio of 1:8 for 2-propanol, while for heptane the minimum value was 0.043% due to the disposal of existing metals, which is very close to the ash percentage of fresh oil (0.00), and the maximum value was 0.097% for 2-propanol, while the maximum value for heptane was 0.11% at a ratio of 1:2. the highest ratios are 1: 8, as ash content has minimum values. this was due to the fact that an excessive amount of work had been done to dissolve some existing pollutants [37]. t. m. naife et al. / iraqi journal of chemical and petroleum engineering 23,1 (2022) 43 50 48 fig. 4. the effect of the solvent to oil ratio on each solvent's ash content 3.7. the effect of extraction temperature fig. 5 shows the effect of the temperature on a raffinate yield at a range from 30 °c to 60 °c (lubricating oil yield), temperature parameter represents the important factors influencing the overall efficiency and performance of the extraction process, the experimental test of the sample was tested at solvent/oil ratio (1:6). the maximum percentage yield of 2-propanol is approximately 92% at 40 °c, while heptane is 84% at 50 °c. at these temperatures, the aromatic compounds' solubility in the solvent results in a drop in extraction efficiency, so good solvent power is another essential advantage that a solvent contains aromatic compounds and their related pollutants [38]. solvent power is probably going to indicate the solvent’s efficiency in extraction process relatively at a low volume. power solubility in many cases increases with temperature at almost, this is may be damage of the selectivity, so, at elevated temperature, when the temperature rises, the development of aromatic compounds necessitates a higher solubility with the lubricant oil, and this is important target [39]. likewise, the dissolving of the target undesirable composition is very low at low temperatures in any of the three solvents because the contaminants and heavy residual aromatics do not completely separate, and the ability to extract chemical contaminants becomes higher due to an increase in solubility and affinity [40]. fig. 5. the effect of the temperature on each solvent's raffinate yield percent 4conclusions in this research, the capacity of the solvent extraction method to refine the utilized lubricating oil was shown to be improved by this research. two types of solvents are employed (heptane and 2-propanol). from the outcomes acquired, the solvent/oil ratio and temperature were very affected on the characteristics and quality. there should be a compromise to be made in operating the process of extraction at the best lower solvent to oil ratio and temperature to minimize cost if the results from this study were scaled-up to an industrial scope for a wider range of applications. this normally needs particular enhancement and optimizing the results of studies. 2-propanol efficiency is better compared to heptane according to the values of characteristics. although 2-propanol further enhanced the viscosity index of the utilized lubricant oil, the extraction method is powerful in eliminating pollutants as they improve the properties of the treated oil: viscosity, specific gravity, pour point, flash point, and ash content. besides, the results show also that when the temperature increases, according to the raffinate yield the quality of the oil is improved at up to 40 °c for 2propanol and 50 °c for heptane. references [1] munirah abdul zali, wan kamaruzaman wan ahmed, ananthy retnam, ngcatina,"concentration of heavy metals in virgin, used, recovered and waste oil: a spectroscopic study", proc. environ. sci. 30, 2015,pp.201-204. [2] c.y. foo, m.y. rosli, s.s. tea, "modeling and simulation of used lubricant oil re– refining process", second world engineering congress sarawak, malaysia, 2002. [3] r. abu-elella, m.e.ossman, r.farouq, m.abd-elfatah, "used motor oil treatment: turning waste oil into valuable products", int. j. chem. biochem. sci. 7, 2015, p.p. 57-67. [4] f. danane, a.ahmia, a. bakiri, n. lalaoui, "experimental regeneration process of used motor oils", rev. des. energies renouvables 17 (2), 2014, p.p. 345351. [5] i. hamawand, t. yusaf and s. rafat, "recycling of waste engine oils anew washing agent", energies ,vol. 6,no.2,.2013. p.p.1023-1049. [6] m. k. jha, "re-refining of used lube oils: an intelligent and ecofriendly option", indian chemical engineering, vol. 473, 2005. pp. 209211. [7] f. o. cotton, "waste lubricating oil: an annotated review". revision deb3001439 of annotated review 1997 betc/ic 79/4, corp; sourcedepartment of energy, bartlesville, okla, usa, 1997. [8] t. bhaskar, m.a. uddin, a. muto, y. sakata, y. omura, k. kimura, y. kawakami,"recycling of waste lubricant oil into chemical feedstock or fuel oil over supported iron oxide catalysts". fuel 83 (1), 2004, p.p.9-15. [9] a.hamad, e. al-zubaidy, and m. e. fayed, "used lubricating oil recycling using hydrocarbon solvents", journal of environmental management, vol. 74, no. 2, 2005pp. 153–159. https://www.sciencedirect.com/science/article/pii/s1878029615006301 https://www.sciencedirect.com/science/article/pii/s1878029615006301 https://www.sciencedirect.com/science/article/pii/s1878029615006301 https://www.sciencedirect.com/science/article/pii/s1878029615006301 https://www.sciencedirect.com/science/article/pii/s1878029615006301 http://www.iscientific.org/wp-content/uploads/2020/05/10-ijcbs-15-07-16.pdf http://www.iscientific.org/wp-content/uploads/2020/05/10-ijcbs-15-07-16.pdf http://www.iscientific.org/wp-content/uploads/2020/05/10-ijcbs-15-07-16.pdf http://www.iscientific.org/wp-content/uploads/2020/05/10-ijcbs-15-07-16.pdf https://revue.cder.dz/index.php/rer/article/view/448 https://revue.cder.dz/index.php/rer/article/view/448 https://revue.cder.dz/index.php/rer/article/view/448 https://revue.cder.dz/index.php/rer/article/view/448 https://www.mdpi.com/1996-1073/6/2/1023 https://www.mdpi.com/1996-1073/6/2/1023 https://www.mdpi.com/1996-1073/6/2/1023 https://www.sciencedirect.com/science/article/abs/pii/s0016236103002163 https://www.sciencedirect.com/science/article/abs/pii/s0016236103002163 https://www.sciencedirect.com/science/article/abs/pii/s0016236103002163 https://www.sciencedirect.com/science/article/abs/pii/s0016236103002163 https://www.sciencedirect.com/science/article/pii/s0301479704001914 https://www.sciencedirect.com/science/article/pii/s0301479704001914 https://www.sciencedirect.com/science/article/pii/s0301479704001914 https://www.sciencedirect.com/science/article/pii/s0301479704001914 t. m. naife et al. / iraqi journal of chemical and petroleum engineering 23,1 (2022) 43 50 49 [10] nancy zgheib and hosni takache " recycling of used lubricating oil by solvent extraction: experimental results, aspen plus simulation and feasibility study" clean technologies and environmental policy, 2020 | original paper | issue 1/2021,p.p 1-12. [11] a. kamal, f. khan, "effect of extraction and adsorption on refining of used lubricating oil", oil gas sci. technol. 64 (2), 2009, p.p.191–197. [12] k. o. boadu , o. f. joel1, d. k. essumang2 and b. o. evbuomwan," a review of methods for removal of contaminants in used lubricating oil" 26(4): 1-11, 2019; article no.csij.48620,p.p.1-11. [13] khudhair, m.m.; abas k.f.; hameed, t.m.," recycling of used generator oils by different treatment methods ", j. petro. eng. techn. 2(3), 2012, p.p. 29-41. [14] j. d. udonne, "a comparative study of recycling of used lubrication oils using distillation, acid and activated charcoal with clay methods", journal of petroleum and gas engineering, vol. 2, no. 2, 2011, pp. 12–19. [15] a. hamad, e. al-zubaidy, m.e. fayed, "used lubricating oil recycling using hydrocarbon solvent", junviron. manage. 74 , 2005,p.p. 153-159. [16] j. sauners, "used oil refining revolution", lubricants world 6 (9), 1996, p.p. 20-24. [17] n.o. elbasshir, "the effect of design parameters on the solvent extraction performance for recycling of used oil ", m.eng. thesis, thesis university of technology malaysia, 1998. [18] j.h. sherman, "removal transition metals from motor oil using ion exchange resins", environ. technol. 14 (11), 1993, p.p. 1097-1100. [19] m.i. abdul_mutalib, n.o. elbashir, m. sahrif, r. adnan, "practical use of the solubility parameters in determining effective solvent extraction parameters for recycling used lubricating oil", proceedings of rsce98, manila, philippines, 1998, pp. 110-117. [20] j.l. assuncao filho, i.g.m. mora, a.c.s. ramos, "liquid –liquid extraction and adsorption on solid surfaces applied to used lubricant oils recovery", braz. j. chem. eng. 27, 2010, p.p. 687-697. [21] h.a. durrani, m.i. panhwar, r.a. kazi, "rerefining of waste lubricating oil by solvent extraction", mehran univ. res. j. eng. teach. 30 (2), 2011, p.p. 237246. [22] shri, k.c.; mohan, k.s.;sakeer, h.m.;deepa ,p.n.; sara, v.k.,"studies on reuse of re-refined used automotive lubricating oil", j. eng. sci.3(6) , 2014, p.p. 8-14. [23] forsthoffer, w.e. "lube, seal and control oil system best practices". in forsthoffer’s best practice handbook for rotating machinery, 1st ed.; elsevier: oxford, uk, 2011; pp. 347–468. [24] tran t. n. and roman m. b. "determination of metals in lubricating oil by icp-aes", instruments work, vol. 2, 1991, p.p. 1-5. [25] jose c. velasco-calderon, josé luis lopez cervantes, arturo a. garcia-figueroa, and jesús graciafadrique " regeneration of used lubricating oil by solvent extraction and phase diagram analysis" current research in green and sustainable chemistry 3 ,2020, p.p. 1-6. [26] scapin ma,"recycling of used lubricating oils by ionizing radiation process", radiation physics and chemistry, vol.76, issues 11–12, november–december 2007,p.p. 1899-1902. [27] doaa i.osman, sayed k.attia and afaf r.taman, " recycling of used engine oil by different solvent", volume 27, issue 2, june 2018, p.p. 221-225. [28] c.j.a. roelands, "correlational aspects of the viscoity-temperature-pressure relationship of lubricating oils", 1966. [29] r.m. mortier, m.f. fox, s.t. orszulik, eds., "chemistry and technology of lubricants", springer netherlands, dordrecht, 2010. [30] j. rincon, "regeneration of used lubricant oil by polar solvent extraction", industrial & engineering chemistry research, vol. 44, no. 12, 2005, pp. 43734379. [31] firas a, dumitru p "design aspects of used lubricating oil rerefining", 1st edition april 12, 2006. p.p. 114. [32] friday o.n., bamidele i.o., kayode o, a., luter l; "comparative investigation of wear metals in virgin and used lubricant oils", terrestrial aquatic environmental toxicology, 2(1), 2008.p.p.38-43. [33] riazi, m.r.; daubert, t.e. "predicting flash and pour points". hydrocarb. process. 1987, 66, p.p. 81-83. [34] burrows j. a. , heerdt j. c. , willis j. b. ; "determination of wear metals in used lubricating oils by atomic absorption spectrometry". anal. chem., 37 (4), i965, p.p. 579-582. [35] speight, j. g., and exall, d. i., "refining used lubricating oils. crc press, taylor & francis group, boca raton, florida. 2014,ch. 1,2,4 and 7. [36] mahmood, s. m., msc. thesis, "study the effect of different working variables on the re-refining used lubricating oil and reduced the environmental conditions". university of al-nahrain, chemical engineering dep. 2015. [37] j.p. wauquier, p. trambouze, j.p. favennec, "petroleum refining". editions technip, 1995. [38] a.-h. a. mohammed and m. j. yass kheder, “the effect of extraction temperature and solvent to oil ratio on viscosity index of mixed-medium lubricating oil fraction by using solvents extraction”, ijcpe, vol. 10, no. 2, pp. 13–18, jun. 2009. [39] s. al-zahrani, et al., "used lubricating oil regeneration by various solvent extraction techniques", j. ind. eng. chem. 19 (2013) 536–539. [40] r. f. abdul-saheb and m. a. mohammed, “a comparative study of the influence of different types of polymers on viscosity index and pour point of iraqi base oils”, ijcpe, vol. 20, no. 3, pp. 7–13, sep. 2019. https://link.springer.com/article/10.1007/s10098-020-01893-0 https://link.springer.com/article/10.1007/s10098-020-01893-0 https://link.springer.com/article/10.1007/s10098-020-01893-0 https://link.springer.com/article/10.1007/s10098-020-01893-0 https://link.springer.com/article/10.1007/s10098-020-01893-0 https://link.springer.com/article/10.1007/s10098-020-01893-0 https://ogst.ifpenergiesnouvelles.fr/articles/ogst/abs/2009/02/ogst08046 https://ogst.ifpenergiesnouvelles.fr/articles/ogst/abs/2009/02/ogst08046 https://ogst.ifpenergiesnouvelles.fr/articles/ogst/abs/2009/02/ogst08046 https://ir.ucc.edu.gh/xmlui/handle/123456789/5821 https://ir.ucc.edu.gh/xmlui/handle/123456789/5821 https://ir.ucc.edu.gh/xmlui/handle/123456789/5821 https://ir.ucc.edu.gh/xmlui/handle/123456789/5821 https://academicjournals.org/journal/jpge/article-abstract/f9f2dd03170 https://academicjournals.org/journal/jpge/article-abstract/f9f2dd03170 https://academicjournals.org/journal/jpge/article-abstract/f9f2dd03170 https://academicjournals.org/journal/jpge/article-abstract/f9f2dd03170 https://academicjournals.org/journal/jpge/article-abstract/f9f2dd03170 https://www.sciencedirect.com/science/article/pii/s0301479704001914 https://www.sciencedirect.com/science/article/pii/s0301479704001914 https://www.sciencedirect.com/science/article/pii/s0301479704001914 https://www.tandfonline.com/doi/abs/10.1080/09593339309385387 https://www.tandfonline.com/doi/abs/10.1080/09593339309385387 https://www.tandfonline.com/doi/abs/10.1080/09593339309385387 https://www.scielo.br/j/bjce/a/wmjbgjrpbrk8wx6j4srkn5j/?format=pdf&lang=en https://www.scielo.br/j/bjce/a/wmjbgjrpbrk8wx6j4srkn5j/?format=pdf&lang=en https://www.scielo.br/j/bjce/a/wmjbgjrpbrk8wx6j4srkn5j/?format=pdf&lang=en https://www.scielo.br/j/bjce/a/wmjbgjrpbrk8wx6j4srkn5j/?format=pdf&lang=en http://www.publications.muet.edu.pk/research_papers/pdf/pdf88.pdf http://www.publications.muet.edu.pk/research_papers/pdf/pdf88.pdf http://www.publications.muet.edu.pk/research_papers/pdf/pdf88.pdf http://www.publications.muet.edu.pk/research_papers/pdf/pdf88.pdf https://www.researchgate.net/profile/deepa-priya-natarajan/publication/346900634_studies_on_reuse_of_re-refined_used_automotive_lubricating_oil/links/5fdae6b8a6fdccdcb8d1c336/studies-on-reuse-of-re-refined-used-automotive-lubricating-oil.pdf https://www.researchgate.net/profile/deepa-priya-natarajan/publication/346900634_studies_on_reuse_of_re-refined_used_automotive_lubricating_oil/links/5fdae6b8a6fdccdcb8d1c336/studies-on-reuse-of-re-refined-used-automotive-lubricating-oil.pdf https://www.researchgate.net/profile/deepa-priya-natarajan/publication/346900634_studies_on_reuse_of_re-refined_used_automotive_lubricating_oil/links/5fdae6b8a6fdccdcb8d1c336/studies-on-reuse-of-re-refined-used-automotive-lubricating-oil.pdf https://www.researchgate.net/profile/deepa-priya-natarajan/publication/346900634_studies_on_reuse_of_re-refined_used_automotive_lubricating_oil/links/5fdae6b8a6fdccdcb8d1c336/studies-on-reuse-of-re-refined-used-automotive-lubricating-oil.pdf https://www.researchgate.net/profile/tran-nham/publication/238101380_determination_of_metals_in_lubricating_oil_by_icp-aes/links/58527b6808aef7d030a4e9b7/determination-of-metals-in-lubricating-oil-by-icp-aes.pdf https://www.researchgate.net/profile/tran-nham/publication/238101380_determination_of_metals_in_lubricating_oil_by_icp-aes/links/58527b6808aef7d030a4e9b7/determination-of-metals-in-lubricating-oil-by-icp-aes.pdf https://www.researchgate.net/profile/tran-nham/publication/238101380_determination_of_metals_in_lubricating_oil_by_icp-aes/links/58527b6808aef7d030a4e9b7/determination-of-metals-in-lubricating-oil-by-icp-aes.pdf https://www.sciencedirect.com/science/article/pii/s2666086520300138 https://www.sciencedirect.com/science/article/pii/s2666086520300138 https://www.sciencedirect.com/science/article/pii/s2666086520300138 https://www.sciencedirect.com/science/article/pii/s2666086520300138 https://www.sciencedirect.com/science/article/pii/s2666086520300138 https://www.sciencedirect.com/science/article/pii/s2666086520300138 https://www.sciencedirect.com/journal/radiation-physics-and-chemistry https://www.sciencedirect.com/journal/radiation-physics-and-chemistry https://www.sciencedirect.com/journal/radiation-physics-and-chemistry/vol/76/issue/11 https://www.sciencedirect.com/science/article/pii/s1110062116302161 https://www.sciencedirect.com/science/article/pii/s1110062116302161 https://www.sciencedirect.com/science/article/pii/s1110062116302161 https://asmedigitalcollection.asme.org/tribology/article/93/1/209/419010/correlational-aspects-of-the-viscosity-temperature https://asmedigitalcollection.asme.org/tribology/article/93/1/209/419010/correlational-aspects-of-the-viscosity-temperature https://asmedigitalcollection.asme.org/tribology/article/93/1/209/419010/correlational-aspects-of-the-viscosity-temperature https://link.springer.com/book/10.1007/978-1-4020-8662-5?noaccess=true https://link.springer.com/book/10.1007/978-1-4020-8662-5?noaccess=true https://link.springer.com/book/10.1007/978-1-4020-8662-5?noaccess=true https://pubs.acs.org/doi/abs/10.1021/ie040254j https://pubs.acs.org/doi/abs/10.1021/ie040254j https://pubs.acs.org/doi/abs/10.1021/ie040254j https://pubs.acs.org/doi/abs/10.1021/ie040254j https://books.google.iq/books?hl=en&lr=&id=qnqnvykyevac&oi=fnd&pg=pp1&dq=%5b31%5d%09firas+a,+dumitru+p+%22design+aspects+of+used+lubricating+oil+rerefining%22,+1st+edition+-+april+12,+2006.+p.p.+114.&ots=ulnezevuyo&sig=s3orlgwow9hrbwcuzyuoma5jzym&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=qnqnvykyevac&oi=fnd&pg=pp1&dq=%5b31%5d%09firas+a,+dumitru+p+%22design+aspects+of+used+lubricating+oil+rerefining%22,+1st+edition+-+april+12,+2006.+p.p.+114.&ots=ulnezevuyo&sig=s3orlgwow9hrbwcuzyuoma5jzym&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=qnqnvykyevac&oi=fnd&pg=pp1&dq=%5b31%5d%09firas+a,+dumitru+p+%22design+aspects+of+used+lubricating+oil+rerefining%22,+1st+edition+-+april+12,+2006.+p.p.+114.&ots=ulnezevuyo&sig=s3orlgwow9hrbwcuzyuoma5jzym&redir_esc=y#v=onepage&q&f=false http://www.globalsciencebooks.info/online/gsbonline/images/0812/taet_2(1)/taet_2(1)38-43o.pdf http://www.globalsciencebooks.info/online/gsbonline/images/0812/taet_2(1)/taet_2(1)38-43o.pdf http://www.globalsciencebooks.info/online/gsbonline/images/0812/taet_2(1)/taet_2(1)38-43o.pdf http://www.globalsciencebooks.info/online/gsbonline/images/0812/taet_2(1)/taet_2(1)38-43o.pdf https://www.osti.gov/biblio/5920149 https://www.osti.gov/biblio/5920149 https://pubs.acs.org/doi/pdf/10.1021/ac60223a035 https://pubs.acs.org/doi/pdf/10.1021/ac60223a035 https://pubs.acs.org/doi/pdf/10.1021/ac60223a035 https://pubs.acs.org/doi/pdf/10.1021/ac60223a035 https://api.taylorfrancis.com/content/books/mono/download?identifiername=doi&identifiervalue=10.1201/b16745&type=googlepdf https://api.taylorfrancis.com/content/books/mono/download?identifiername=doi&identifiervalue=10.1201/b16745&type=googlepdf https://api.taylorfrancis.com/content/books/mono/download?identifiername=doi&identifiervalue=10.1201/b16745&type=googlepdf https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/402 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/402 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/402 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/402 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/402 https://www.sciencedirect.com/science/article/abs/pii/s1226086x12003012 https://www.sciencedirect.com/science/article/abs/pii/s1226086x12003012 https://www.sciencedirect.com/science/article/abs/pii/s1226086x12003012 https://doi.org/10.31699/ijcpe.2019.3.2 https://doi.org/10.31699/ijcpe.2019.3.2 https://doi.org/10.31699/ijcpe.2019.3.2 https://doi.org/10.31699/ijcpe.2019.3.2 t. m. naife et al. / iraqi journal of chemical and petroleum engineering 23,1 (2022) 43 50 50 المذيباتلفصل ببا خدمالمست وقودمعالجة زيت ال 3و مروة فائق عبدالجبار 1سرمد عبدالرزاق رشيد و 1طارق محمد نايف قسم الهندسة الكيمياوية -جامعة بغداد 1 قسم الهندسة الكيمياوية -جامعة النهرين 2 الخالصة العراق والذي -الغازيةتبحث هذه الدراسة في معالجة زيت الوقود المستخدم من شركة محطة كهرباء المسيب بروبانول(. تم فحص وتقييم نشاط أداء هذه المذيبات في -2تم معالجته بمذيبات استخالصية مختلفة )هيبتان و : 1، و 6: 1، 4: 1، 2: 1عملية االستخالص تجريبيًا. متغيرات التشغيل كانت نسبة المذيبات إلى الزيت ) درجة مئوية( ، 60، و 50، 40، 30قة( ، درجات الحرارة )دقي 65، 50، 35، 20( ، زمن الخلط )8 دورة في الدقيقة(. تم دراسة وتحليل هذه المتغيرات. تم تحديد الجودة من خالل قياس وتقييم 500وسرعة الخلط ) الخصائص الهامة وخاصة اللزوجة ، مؤشر اللزوجة ، الكثافة النوعي ، نقطة االنسكاب ، نقطة الوميض ، .الرماد ومحتوى بروبانول( أعطى كفاءة عالية مع أعلى نسبة من إزالة الحمأة مقارنة بالهبتان. -2اكدت النتائج أن المذيب ) مع االخذ بالجوانب وجد ان تحسين أكبر نسبة إلزالة الحمأة كانت عندما تزداد نسبة المذيبات / الزيت االقتصادية للنسبة المثلى. يت الوقود المعاد استخدامه. تشير النتائج إلى أن تحسين خصائص الزيت المعاد تم دراسة الخصائص الهامة لز : 1الزيت /دقيقة ، نسبة المذيب 35بروبانول كانت عند ) -2استخدامه له فعالية كبيرة وأفضل ظروف عمل لـ .درجة مئوية( 50و 6: 1الزيت /دقيقة ، نسبة المذيب 50درجة مئوية( ، وللهبتان ) 40، 6 الكلمات الدالة: زيت الوقود المستخدم، خصائص زيت الوقود و استخراج المذيبات. iraqi journal of chemical and petroleum engineering vol.17 no.1 (march 2016) 7182 issn: 1997-4884 synthesis and characterization of nanocrystalline micromesoporous zsm-5/mcm-41 composite zeolite najwa saber majeed and asir abduljabbar saleh* chemical engineering department, college of engineering, university of baghdad * department of student affairs and authentication, university of baghdad abstract nanocrystalline micro-mesoporous zsm/mcm-41 composite was synthesized using alkaline treatment method and two step of crystallization in poly tetraflouroethylene (ptfe) lined autoclave. the synthesized zeolites was characterized by x-ray diffraction (xrd), scanning electron microscopy (sem), transmission electron microscopy (tem), atomic force microscopy (afm), fourier transport infrared (ftir), and n2 adsorption-desorption (bet). it was approved that the best results for alkaline leaching can be got with 1.5m naoh solution. high surface (bet) area of 630 m 2 /g with pore volume of 0.55 cm 3 /g has been got. afm reports showed a nano-level size for average particle size of 50nm. key words: zsm-5/mcm-41, micro-mesoporos, nanocrystalline, alkaline leaching, composite molecular sieves. introduction the need of eco-friendly and more profitable and efficient technology for renewable sources of energy and fuel has encouraged and enhanced the potential to use and develop porous materials and especially micromesoporous composite molecular sieves.the goal of mesopore-modified zeolite is to create mesopores in zeolite to increase the accessibility to the internal surface. [1]. micro-mesoporous composite zeolites have high specific surface area (bet) and pore volume. the most disadvantage of zeolite is the small size of apertures (less than 0.8nm) and cavities less than 2nm, which imposes mass transfer problems because of diffusional limitations for molecules and consequently on reactions which can cause back pressure on flow. overcoming these problems created by zeolite structure, several methodologies were adopted; among them are the synthesis of zeolite with larger pores and decreasing the zeolite down to nano-level size. comparing the dimensions of the zeolite micropores (< 2nm), mesopores (2-50nm) allow quicker transfer of reacting and produced molecules in the zeolite framework, and gives faster mass transfer of the reactants and products to and from the active sites. the basic methodology to improve diffusion is to shorten the length of the micropore channels or/and to widen the pore diameter [2]. iraqi journal of chemical and petroleum engineering university of baghdad college of engineering synthesis and characterization of nanocrystalline micro-mesoporous zsm-5/mcm-41 composite zeolite 72 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net mcm-41 is one kind of mesoporous zeolite (molecular sieve) and exhibits a hexagonal arrangement, it has pore diameter ranging from 1.5 to 10nm, which gives much less transfer resistance comparing with zsm-5. but the disadvantages of mcm-41 has nearly no acidity and poor hyderothermal stability. a combination of zsm-5/mcm-41 could have a dual distribution of pore size, which would utilize the channel advantage of mesoporosity structure of mcm-41 with the thermal stability and several dual templating methods for preparation of mesoporous zeolite materials have been suggested like macrotemplating by using carbon black particles for synthesis of zsm-5 having wide pore size distribution (10100 nm), or using a nanocasting by colloid-imprinted carbons as templates for synthesis of zsm-5 small particles [2] . jacobsen, et al. [4] synthesized 1230 nm mesoporous zsm-5 by inserting the gel components with multiwall carbon nanotubes (mwcnt). leaching zsm-5 with alkaline solution, sodium hydroxide (naoh) was recently used to develop mesopores in mfi zeolite [5,6,7].as it is well established that acid treatment eliminates framework al atoms, alkali treatment was preferred to selectively eliminate framework si atoms. it is also established and shown that mesopore formation is provoked at boundaries or defect sites of the zeolite crystals. groen, et al. [7] and groen, et al. [8] studied the role of aluminum on the desilication process and gave a description for the mechanism of pore formation in mfi zeolites. in mole ratio si/al < 20, the presence of high al concentrations inhibits si from being eliminated, leading to limit pore formation. high si/al of >> 50, show excessive and unselective si dissolution, and leads to create large pores. a ratio of si/al of 25-50 was established to be the optimum for development of mesoporosity with keeping al atoms. the influence of the zeolite framework si/al ratio on si extraction and the mechanism of porosity development are shown in fig.1. fig. 1, schematic representation of the effect of content of al on the alkaline leaching of mfi zeolites [7] the explanation of that was, for negatively charged alo4tetrahedron, hydrolysis of the si-o-al bond in the presence of ohis prevented compared to the relatively easy breakage of the si-o-si bond in the absence of neighbouring al tetrahedral. su, et,al.[9] by nuclear magnetic resonance (nmr) elucidated that the dissolution of the zeolite framework at si-o-si linkages. the inactivity of the si-o-al bond in alkali processing keeps the bronsted acid sites (bridging oh species on si-o-al linkages. najwa saber majeed and asir abduljabbar saleh -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 73 many different methodologies have been adopted to increase the accessibility in zeolites, one of them is to synthesis micro-mesoporous composite materials i e to synthesize materials which have larger pore and still have the catalytic ability of zeolites [3]. nam, et al. [10] investigated the synthesis of multiporous composite (mc-zsm-5/mcm-41) by two steps, the first step was to prepare the zsm-5 seeds by using si-containing solution, al(so4).18h2o, template agent tetrapropylammonium bromide (tpabr) and sulfuric acid the mixture was stirred for 2h to get homogenous gel , then transferred into an autoclave at 150 o c for 10-15h to form zsm-5 seeds. the second step, is to add cetyltrimethyl ammonium bromide (ctabr) to zsm-5 zeolite seed with vigorous stirring at room temperature for 1h. the gel was transferred into autoclave at temperature 150 o c for 10-15h. song, et al.[3] investigated the synthesis of mcm-41 composite from zsm-5 zeolite, they used leaching by alkaline method, preparing first zsm-5 zeolite (sio2/al2o3 ratio is 54) then 5 g of zsm-5 zeolite was added to 150 ml of a solution of sodium hydroxide (1m) and stirred for 1 h at 353 k. (2) prepare 10 wt.% cetyltrimethylammonium bromide (ctab) . the (ctab) solution was added to zsm-5 alkalined suspended solution with stirring. the ph value was adjusted to 10.5 by drop wise addition of 2m h2so4 solution with vigorous solution. the solution mixture was then transferred into an autoclave and heated at 383 k for 48h at autoclave. the results of xrd show that the samples synthesized have the ordered hexagonal mesoporous structure of mcm-41-type molecular sieves. also it shows that diffraction peak due to mfi-type framework of 8~10⁰ , 23~25⁰ and 45 ⁰.the bet specific surface area was 960 m2/g with pore volume of 0.96 and 0.24 cm3/g for mesopores and micropores respectively. tang, et al. [11] investigated the synthesis of micro–mesoporous zsm5/mcm-41 composite also used alkaline leaching method , by using different concentration of alkaline solution from 0.5 mol/l to3.5 mol/l and 2.0 g zsm-5 zeolite were alkalined with10 ml naoh at 40 ◦c for 1 h. zsm-5 zeolite solution consisting of silicon aluminum fragments was formed. then 25ml of 10wt% of (ctab) solution was added into the alkaline solution of zsm-5 and stirred for 1h. the resulting solution was transferred in an autoclave with crystallization under 110 ◦c for 24 h. a second crystallization step under same temperature and carried out after cooling the autoclave and adjusting the ph of the crystallization liquid to 8.5. experimental 1materials the materials used in preparation of zsm-5 and composite zsm-5/mcm41 samples are shown in table 1 below: 2procedure for sample preparation zsm-5 was prepared first [13], the template tpaoh (2.9g) and teos (36 g) were stirred (300 rpm) with (40 ml) deionized water in magnetic stirrer for 1h. trien (1m) then was added, naoh (2.05 g) dissolved in (40ml) deionized water was added also to make solution 1. aluminum isopropoxide (aip) 0.82 g was added to 40 ml deionized water and stirred for 1h to make solution 2. synthesis and characterization of nanocrystalline micro-mesoporous zsm-5/mcm-41 composite zeolite 74 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net the resulting mixture (solution 2) was added dropwise to solution 1 with vigorous stirring (500rpm) in mechanical stirrer for 2h. the resulting gel was poured into the autoclave, the inside volume of teflon insert is 200ml and were filled to about 65% of its volume. a stir bar was placed inside the teflon insert for stirring purpose. the autoclave then operated at 170 o c and 72h. the zeolite produced then washed by distilled water and filtered, then dried in oven at 100 o c for 24h. calcination was done in electrical furnace at 550 o c and 8h, the temperature ramp was 1 o c/min the zeolite composition is as following (stoichiometric calculation): al2o3:68sio2:5.4tpa:10na2o:2.6trie n:2626h2o table 1, materials used in preparation of samples companysupplier formula function material no. sigma aldrich c8h20o4si silica source tertaethylorthosilicate (teos) 1. wuhan kemiworks,chemical co.ltd. c19h42brn surfactant (template) cetyl trimethyl ammonium bromide (ctab) 2. sigma aldrich c9h21alo3 alumina source aluminum isopropoxide(aip) 3. wuhan kemiworks chemical co.,ltd. c12h28noh template (osda) tetrapropyl ammonium hydroxide( tpaoh) 4. sigma aldrich naoh mineralizer (alkaline agent) sodium hydroxide 5. fluke ag nh2ch2ch2(nhch2ch2)2nh2 chelating agent triethylenetetramine (trien) 6. fig. 2, twin autoclave lined with ptfe najwa saber majeed and asir abduljabbar saleh -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 75 fig. 3, design of the autoclave lined with ptfe zsm-5/mcm-41 samples were prepared as following: 12g of zsm-5 prepared above was dispersed in 15 ml of a solution of sodium hydroxide (naoh) and stirred for 1h at 40 o c, different molarity for sodium hydroxide aqueous solution were used (1.5m, 2.0m, 2.5m). 23.75g of cetyltrimethyl ammonium bromideto be dissolved in deionized water to get 10 wt. % aqueous solutions and stirred for 30min. 3the obtained slurry solution in (1) was added to (ctab) solution in (2) and adjust the ph value of reaction mixture to 10.5 by adding drop wise of 1m h2so4 solution with vigorous stirring for 1h. 4the reaction mixture in (3) was transferred into the autoclave lined with ptfe as shown in figure 1 and operates at 110 o c for 24h. 5cool the autoclave and adjust the ph of mixture to 8.5 by drop wise adding of 1m h2so4 with vigorous stirring. 6close and operate the autoclave again for second step of crystallization at 110 o c and 24h. 7the zeolite product then washed, filtered, and dried in oven at 100 o c for 24h, then calcined at 550 o c and 8h. 8bi-metal loading for the synthesized zeolite was done by wet incipient impregnation method; the percentage of loading was 6 wt. % for copper and 6 wt. % for cobalt. the samples of zsm-5/mcm-41 prepared are shown in table 1. table 2, samples conditions for composite zsm-5/mcm-41 no. sample code weight of zeolite,g volume of ctab solution (10wt %) ml molarity of alkaline solution , m volume of alkaline solution,ml crystallization (2 step) temperature o c/time,h 1. cz-01 2 37.5 1.5 m 15 110c/24h 2. cz-02 2 37.5 1.5 m 15 110c/24h 3. cz-03 2 37.5 1.5 m 15 110c/24h 4. cz-04 2 37.5 1.5 m 15 110c/24h 5. cz-05 2 37.5 2.0 m 15 110c/24h 6. cz-06 2 37.5 2.5 m 15 110c/24h 7. cz-07 5 62.5 1.5 m 25 110c/24h synthesis and characterization of nanocrystalline micro-mesoporous zsm-5/mcm-41 composite zeolite 76 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net characterization the xrd patterns of zsm-5 and zsm-5/mcm-41 zeolites were determined using instrument d2 phaser/bruker (germany 2010) using cukα radiation nickel filter (λ= 1.54a o ).data were collected within 2θ 41, with a 0.02 o 2θ-step and 0.5s per step, 30kv and 10ma x-ray was transform infrared (ftir) by schimazdu-ira, affinity-1, using kbr wafer 1wt. % zeolite and 99wt.% kbr to check and record the peaks at specified wave lengths corresponding to zsm-5/mcm-41 and in the range of 400-4000 cm -1 . the morphology of composite zsm-5/mcm-41 was studied by scanning electron microscopy using te scan, vega lm, czech. the particle size and topoghraphy on nano-level size, were determined by atomic force microscopy using an aa3000/angstrom advance inc, usa. adsorption-desorption n2 bet surface was measured by surface analyzer/q surf series/italy and asap 2020/usa. the structure of synthesized nanocrystalline samples were investigated by transmission electron miroscopy by carl ziess-em10c100kv-germany instrument. fig.4, xrd pattern for prepared sample of zsm-5 zeolite results and discussion 1x-ray diffraction the xrd-pattern of prepared sample of zsm-5 was examined, and showed that the only phase obtained was for zsm-5, the peaks at 2θ ranges of 7-9o and 22.5-24.5 are identical to the theory and typical [14]. figure 3 show the pattern for prepared zsm-5 zeolite, the typical peaks are well appeared in the pattern. the results of xrd patterns of nanocrystalline micromesoporous zsm-5/mcm-41 are shown in figure 4 for samples cz01, cz05, and cz06. the molarity of alkaline (naoh) solution were 1.5m, 2.0m, and 2.5m respectively. the difference in crystallinity is clearly shown because of the effect of increasing alkalinity which cause the dissolution and desilication of silica by alkaline leaching led to increased loss in zsm-5 phase. the results also showed that samples prepared have the ordered hexagonal mesopores structure of mcm-41 zeolite, and was observed najwa saber majeed and asir abduljabbar saleh -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 77 in the peaks at 2θ = 2-10o, and they are typical, figure 4 showed these.facts. fig. 5, xrd patterns for samples cz01, cz05, and cz06 alkaline leached 1.5, 2, 2.5m respectively 2atomic force microscopy (afm) the particle size distribution and topography was investigated by atomic force microscopy, with different topography pixels (536-528). afm images for 2 and 3-dimensional surface profiles showed the detailed observation of nanometer size events and the layer growth of crystals of zeolite, and as shown in figures.5and.6. granulatory cumulation distribution reports showed that a nano-size level has been got for zsm-5/mcm-41 zeolite down to 56.7 nm, as shown in figure 7 below: fig. 6, afm 3-dimensional image for sample cz01 fig. 7, afm 2-dimensional image for sample.cz01 fig. 8, granularity cumulation distribution chart for sample cz01 synthesis and characterization of nanocrystalline micro-mesoporous zsm-5/mcm-41 composite zeolite 78 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net in table 3 showed the particle size and distribution range for all samples of zsm-5/mcm-41. table 3, particle size and distribution range for prepared samples range of particles distribution,nm ave. particle diam., nm sample 30-110 n.m 40-80 35-80 60-100 55-105 40-100 66.8 n.m 62.8 58.5 72.7 77.1 56.7 cz-01 cz-02 cz-03 cz-04 cz-05 cz-06 cz-07 3surface area and pore volume the micro-mesoporous zsm5/mcm-41 showed an increase in bet surface and pore volume, and the best results were given by samples cz01, cz03, cz04, cz07, which they were alklined leached by 1.5m (naoh solution). the results as mentioned in table 4 below, the average bet surface and pore volume of above mentioned samples are 612 m 2 /g and 0.5421 cm 3 /g respectively. from figure 8 for n2 adsorption-desorption isotherm, it is clearly shown that the material has mesopore and micropore characteristics. at a relative pressure < 0.3 the increase in the amount adsorbed corresponds to the filling of micropores and little bit of mesopores in zsm-5. at relativepressure range from 0.3-0.5 a rise of sorption which indicates the presence of mesopores. it showed a type ɪ hysteresis loop at relative pressure range 0.85-1.00. this finding is well matched with previous works [3, 12, and 18]. table 4, parameters results for prepared samples of zsm-5/mcm-41 crystallinity % pore volume,cm 3 /g s.surface(bet), m 2 /g ave.particle diam, nm sample 76.2 0.5449 630 66.8 cz-01 64.7 0.4338 490 n.m.(not measured) cz-02 107.5 0.5414 537 62.8 cz-03 101.7 0.6482 707.7 58.5 cz-04 85.2 0.8362 1030.9 72.7 cz-05 50.8 0.7769 923.2 77.1 cz-06 94.2 0.434 575.9 56.77 cz-07 4fourier transport infrared (ftir) the figure 9 for prepared samples of micro-mesoporous zsm-5/mcm-41, showed that there are small shift in band near 1100 cm -1 to slightly decreased as the treatment of alkaline solution increased from 1.5m (naoh) for cz01 (black line), cz03 (red line), cz04 (green line to 2.0m (naoh) for cz05 (blue line), then to 2.5m for cz06 (gey line). the gradual shifting of the band at 1100 cm -1 towards slightly lower wave number, accompanied with a decrease of the band near 440-450 cm -1 . this show and indicate formation of amorphous silica on the surface of zsm-5 [15, 16], and coincided with previous work [17]. najwa saber majeed and asir abduljabbar saleh -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 79 fig .9, isotherm plot for zsm5/mcm-41, sample cz03 fig. 10, ftir spectra (merge) for samples cz01, cz03, cz04, cz05, and cz06 5scanning electron microscopy sem images for composite zsm5/mcm-41 are shown in fig.10. it is clearly revealed that some of zsm-5 crystals are subjected to some faults and cracks on the surface of zsm-5 particles because of de-agglomeration of crystals, which is a consequence of alkali treatment and cleavage of intracrystalline si-o-si bonds. these cracks increase with the increase of the duration and molarity of alkali treatment. this finding is well matched with the previous works [11, 17]. fig. 11, scanning electron microstructure image for zsm5/mcm-41, sample cz01 6transmission electron microscopy the structure of synthesized nanocrystalline samples of zsm5/mcm-41 were investigated by transmission electron microscopy. tem images are shown in fig.11 and fig.12, for composite zeolite loaded with copper and cobalt.it can be indicated the well-ordered hexagonal arrays of mesopores structure of mcm-41 which are interconnected with framework of zsm-5. the small circular shape and dark spots are for the loaded copper and cobalt oxides and have mean diameter 3.346nm as shown in histogram size distribution. these images are well agreed with previous works [3, 10]. synthesis and characterization of nanocrystalline micro-mesoporous zsm-5/mcm-41 composite zeolite 80 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net fig. 12, tem image for cu-co-zsm5/mcm-41 with histogram size distribution fig. 13, tem image for cu-co-zsm5/mcm-41 7alkaline treatment alkaline treatment method for getting mesoporosity proved to be a successful method to combine two types of zeolite in which their physical and catalytic properties are complementary for each other, in other words it combines the mesoporosity of mcm-41 and acidity of zsm-5. the best concentration of alkaline solution of 1.5m in which best characteristics got concerning bet surface, pore volume, crystallinity, as mentioned in table 4, and nano-size level. surfactant or second template, ctab gave promising results in two step crystallization process to get composite zeolite, and when comparing typical isotherms shown by na et al.,[18] with synthesized sample cz01 reveal that the sample cz01 synthesized with c19 (cetyl trimethyl ammonium bromidectab-c19h42brn), showing that pores in this system can be controlled by varying the chain length of alkyl methyl ammonium surfactant. ph control during the preparation procedure play a vital role in getting best result. conclusions 1nanocrystalline micro-mesoporous zsm-5/mcm-41 composite zeolite can be synthesized successfully by alkaline treatment of zsm-5 followed by thermal treatmentconventional method using two step crystallization and ctab as second template. 2xrd-patterns, of prepared samples of composite zsm-5/mcm-41 zeolite showed excellent agreement with typical pattern and theory. 3the optimum concentration of alkaline (naoh) solution is 1.5m , giving best characteristics results. 4atomic force microscopy reports revealed nano-level size for average particle size. najwa saber majeed and asir abduljabbar saleh -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 81 5bi-metal loading of copper and cobalt were conducted on zsm5/mcm-41 by wet incipient impregnation method. tem images revealed good distribution of metal with average diameter of 3.346 nm. acknowledgements the authors express their grateful appreciation to the ministry of oilpetroleum r & d center for conducting bet surface area, the ministry of science and technology (previously)-nano-lab. for sem test, college of science for xrd, afm, and ftir tests. references 1ooi,y.s.;zakaria,r.;mohamed,a.;b hatia,s.(2004),” composite mcm41/zsm-5 as a cracking catalyst for the production of liquid fuel from palm oil”, the 4 th seminar of national science fellowship. 2tao,y.;kanoh,h;abrams,l.;kaneko ,k.(2006)”mesopores-modified zeolites:preparation,characterizatio n,and application”,j.of chemical revision,vol.106,p.896-910. 3song,c.m.;jiang,j.;yan,z.f.(2008)” synthesis and characterization of mcm-41-type composite materials prepared from zsm5”,j.of porous materials,vol.15,p.2o5-211. 4jacobsen,c.j.h.;madsen,c.;jansen, t.v.w.;jakobsen,h.j.;skibsted,j.(2 000)”zeolites by confined space synthesischaracterization of the acid sites in nanosized zsm-5 by ammonia desorption and al/simas nmr spectroscopy”,j.of microporous and mesoporous materials,issue 1-2,vol.39,p.393401. 5suzuki,t:okuhara,t.(2001)”change in pore structure of mfi zeolite by treatment with naoh aqueous solution”,j.of microporous and mesoporous materials,issue 2, vol. ,p.153-161. 6groen,j.c.;peffer,l.a.a.;perezramirez,j.p.(2003)”pore size determination in modified microand mesoporous materials pitfalls and limitation in gas adsorption data analysis”,j.of microporous and mesoporous materials,issue 13,vol.60,p.1-17 7groen,j.;jansen,j.;moulijn,j;perezramirez,j.(2004”optimal aluminum-assisted mesoporosity development in mfi zeolites”,j.of physical chemistry materials,vol.108,p.13062. 8groen,j.c.;moulijn,j.;perezramirez,j.(2005) “decoupling mesoporosity formation and acidity modification in zsm-5 zeolites by sequential desilicationdealumination”,j.of microporous and mesoporous materials,vol. ,issue 2,p.153-161. 9su,l.;liu,l.,zhuang,j.;wang,h.;li, y.;shen,w.;xu,y;bao,x.(2003)”cr eating mesopores in zsm-5 by alkali treatment:a new way to enhance the catalytic performance of methane dehydroaromatization on mo/hzsm-5 catalysts”,j.of catalysis letters,no.34,vol.91,p.155-167. 10nam,l.t.h.;vinh,t.q.;loan,n.t. t.;tho,v.d.s.;yang,x.y.;su,b.l.( 2011)”preparation of bio-fuel by catalytic cracking reaction of vegetable oil sludge”,j.of fuel,vol.90,p.1069-1075 11tang,q.;hang,x.;zheng,y.;wang, j.;li,h.;zhang,j.(2012)”catalytic dehydration of methanol to dimethyl ether over micromesoporous zsm-5/mcm-41 composite molecular sieves”,j.of applied catalysis a:general,vol.413-414,p.36-42. 12huiyong,c.;hongxia,x.;xianying, c.;yu,q.(2009)”experimental and molecular simulation studies of synthesis and characterization of nanocrystalline micro-mesoporous zsm-5/mcm-41 composite zeolite 82 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net zsm-5-mcm-41 micromesoporous molecular sieve”,j.of microporous and mesoporous materials,vol.118,p.396-402. 13alnaama,a.a.s.(2015)”synthesis of nanocrystalline zeolite and its application in biodiesel production”,ph.d.thesis submitted to department of chemical engineering,college of engineering,university of baghdad. 14treacy,c.;higgins,j.(2001)”collec tion of simulated xrd powder patterns for zeolites”,elsevier,4 th edition,new york. 15camblor,h.;corma,a;valencia,s(1 998)”characterization of nanocrystalline zeolite beta”,j.of microporous and mesoporous materials,vol.25,issue (1-3),p.5974. 16cimek,a.;komunjer,l.;subotic,b.; aiello,r.;crea,f.;nastro,a(1994)” kinetics of zeolite dissolution:part 4.influence of the concentration of silicone in the liquid phase on the kinetics of zsm-5 dissolution”,j.of zeolites,issue 3,vol. 14,p.182-189. 17kalita,h.;talukdar,a.(2011)”studi es on stability of nanocrystalline mfi zeolite synthesized by a novel method agaist oh attack”,j.of mateials chemistry and physics,vol.129,p.371-379. 18na,j.;liu,g.;zhou,t.(2013)”synth esis and catalytic performance of zsm-5/mcm-41 zeolites with varying mesopores size by surfactant-directed recrystallization”,j.of catalysis letters,vol.143,p.267-275 available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.22 no.2 (june 2021) 17 – 26 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: haider a. al-jendeel , email: haider.aljendeel@coeng.uobaghdad.edu.iq, name: hussein qasim hussein, email: husseinqassab@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. advanced study of promoted pt /sapo-11 catalyst for hydroisomerization of the n-decane model and lube oil haider a. al-jendeel and hussein qasim hussein chemical engineering department, university of baghdad, baghdad, iraq abstract sapo-11 is synthesized from silicoaluminophosphate in the presence of di-n-propylamine as a template. the results show that the sample obtained has good crystallinity, 396m 2 /g bet surface area, and 0.35 cm 3 /g pore volume. the hydroisomerization activity of (0.25)pt (1)zr (0.5)w/sapo-11 catalyst was determined using n-decane and base oil. all hydroisomerization experiments of ndecane were achieved at a fixed bed plug flow reactor at a temperature range of 200-275°c and lhsv 0.5-2h -1 . the results show that the n-decane conversion increases with increasing temperature and decreasing lhsv, the maximum conversion of 66.7 % was achieved at temperature 275°c and lhsv of 0.5 h -1 . meanwhile, the same catalyst was used to improve base oil specification by increasing viscosity index and decreasing pour point. the isomerization reaction conditions, employed are temperature (200-300)ºc, the liquid hourly space velocity of 0.5-2h -1, and the pressure kept atmospheric. the present study shows that pt zr w/sapo-11 minimizes the pour point of lubricating oil to -16°c at isomerization temperature of 300°c and lhsv of 0.5 h -1 and viscosity index 134.8. keywords: sapo-11; isomerization; n-decane; bifunctional catalysts; lube oil; pour point; viscosity index. received on 06/01/2021, accepted on 16/04/2021, published on 30/06/2021 https://doi.org/10.31699/ijcpe.2021.2.3 1introduction many processes have been proposed to improve the properties of base oil by upgrading the ordinary base oil which would be converted into other products [1]. base oil hydroprocessing includes hydrocracking and catalytic dewaxing processes that have been used. the hydrocracking process is converted the low viscosity index of long-chain alkanes with a high viscosity index of lower chain alkanes. [2-4]. isodewaxing is a new technology for improving the hydroisomerization process. in this process isomerization of long-chain alkanes gives higher amounts of base oil yield, higher viscosity index, and low pour point with respect to other processes like; solvent dewaxing, and catalytic dewaxing. also, this process improves other properties of base oil such as viscosity index and pour point (highest vi component and lower pour point) and this is due to the isomerization of waxes [5]. producing low pour point and high viscosity index base oil by isomerization of long-chain n-alkanes is important in petrochemical industries and petro refining, also to get the required identification of converting n-alkanes into their monobrached isomers [6]. isomerization is a fundamental molecular transformation without altering the number of atoms present in the molecules. this reaction has both scientific and commercial importance in petroleum, lubricants, and various industries [7,8]. catalysts with 12 mr (member ring) pores channels can give mono-branched, di-branched, and tri-branched hydrocarbons, so the isomerization process using these catalysts tend to give a significant amount of diand tri branched. on the other hand catalysts with 10 mr pores which tend to give mono-branched hydrocarbons will be more suitable choice for the isodewaxing process than catalysts with 12 mr [9, 10]. for good performance, suitable catalysts are used for the conversion of hydrocarbons. many catalysts were used for isomerization of long-chain n-alkanes, but sapo-11 was one of the most active for isomerization of long-chain alkanes and this is due to its medium acidities and appropriate pore structure (one-dimensional 10membered-ring channel of 0.39 nm x 0.63 nm) and ael pore structure [11]. the microporous structure of sapo11 prevents producing multi-branched isomers. so, sapo-11 showed excellent conversion of hydrocarbons into isomers [12]. however, it is observed that the active sites for isomerization are found near the pore mouths of the zeolite. consequently, the realization of sapo-11 with a suitable pore structure is important to produce the mono-branched isomers from long-chain n-paraffins [13]. the acidity and pore structure of support is the important factors influencing the hydroisomerization performance of the bifunctional catalyst [14]. for the catalyst activity and isomerization selectivity, the acid site density and the acid strength distribution are both important [15]. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:haider.aljendeel@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2021.2.3 h. a. al-jendeel and h. q. hussein / iraqi journal of chemical and petroleum engineering 22,2 (2021) 17 26 18 strong acidity promotes hydrocracking, whereas medium-strength acidity is favorable to high isomerization selectivity [16, 17]. the present study aimed to synthesis the sapo-11 catalyst with improved characteristics for isomerization of the long-chain n-alkanes. characterization of the prepared catalyst by detection of the x-ray configuration, ftir analysis, particle size, surface area, pore volume, and adsorption isotherm.
 deposition of platinum, zirconium, and tungsten on the sapo-11 to produce pt zr w/ sapo-11 catalysts and study the isomerization of a simulated model (n-decane) and base oil (after furfural extraction) to detect the generation of the relevant isomers in a fixed bed reactor unit. 2experimental work 2.1. chemicals n-decane 99% ( bdh, england) and 3ss (base oil after the furfural extraction process from al-dura refinery) are used as feedstock in this study. ortho phosphorous acid (85 wt% h3po4) (panreac, spain); aluminum isopropoxide (bdh, england); di-npropylamine, m.wt. 101.19 (bdh, england) as template. silica sol. 99.9% (qingdaw jiyida, china); deionized water; poly vinyl alcohol (pva) 99% (sigma) and ɤnano-alumina. 99.99% (hwnano, china) as a binder; are used to synthesized sapo-11. 2.2. synthesis of sapo-11 sapo-11 was synthesized at 190°c crystallization temperature, 550°c calcination temperature with aging and double water contents according to hussein and aljandeel [18]. 2.3. synthesized of pt/ sapo-11 and pt zr w/ sapo-11 for preparing 0.25wt.% of pt on 50 g of sapo-11 by impregnation method. the carrier catalyst sapo-11 was dried at 110 º c with air for two hours. the impregnation requires an appropriate solution of hexchlorplatinic acid containing 0.368 g of h2ptcl6 and deionized water till the volume of solution equal to the pore volume of 50 g under vacuum. the impregnated catalyst was then dried at 110 º c, overnight and calcinated at 300 º c for 3 hours in a furnace with dry air [19]. while preparing pt zr w/sapo-11 the mole ratio of w/zr used in this work was 2. the selected ratio was based on the work of chang et al. [20] who suggested the ratio of w/zr was from 1 to 5. for the preparation of 50g catalyst, the impregnation solution was prepared by dissolving 1.27 g ammonium meta tungsten and 1.065 g zirconium tetrachloride and deionized water till the volume of solution equal to the pore volume of 50 g (i.e. 16 ml). the co-impregnation process was carried out under a vacuum. the impregnation solution was added as drop wise with mixing for homogenous distribution at a fixed temperature of 80 º c. the impregnated extrudates were then dried at 110 º c, overnight and calcinated at 500 º c for 2 hours in a furnace with air and then stored in a desicator. the concentrations of w and zr were measured by atomic absorption spectrometer (pye unicam sp9) and found to be 1 and 0.5 wt% respectively. the next step is to prepare 0.25wt.% of pt on 50g of zr w/sapo-11 by the impregnation method. the carrier catalyst zr w/sapo-11 was dried at 110 º c with air for two hours then the same steps used for preparing zr w/sapo-11 catalyst were adopted apart from the fact that the temperature of the operation was decreased to 40 º c instead of 80 º c. the impregnation requires a proper solution of hexchlorplatinic acid containing 0.368 g of h2ptcl6 and 16 ml of deionized water for a 50 g catalyst. the impregnated extrudates were then dried at 110 º c overnight and calcinated at 300 º c for 3 hours in a furnace with dry air. 2.4. sapo-11 characterization a. x-ray diffraction (xrd) the prepared sample was tested using x-ray diffractometer shimadzu srd 6000, japan, with cu wavelength radiation 1.54060 cm -1 in the 2 theta range from 5-60°, and fixed power source 40kv, 30ma. xrd for prepared samples was performed at the ministry of science and technology. b. x-ray florescence (xrf) the percentage of oxides was tested using x-ray fluorescence (spectro xeros, ametek, germany) germany. xrf sample was performed at university of baghdad/college of science/ department of geology. c. afm average particle size was tested at the department of chemistry/ college of science/ university of baghdad using atomic force microscope device (type angstrom, scanning probe microscope, advanced inc, aa 3000, usa). d. bet surface area and pore volume the specific surface area was determined by the brunauer-emmett-teller method using 0.01 as the value of maximum relative and pore volume was performed using a micrometric asap 2020. h. a. al-jendeel and h. q. hussein / iraqi journal of chemical and petroleum engineering 22,2 (2021) 17 26 19 the samples were disarmament of gas for 2 hr under vacuum at 250°c. surface area and pore volume samples were performed at prdc laboratory, ministry of oil /iraq. e. fourier –transform infrared spectroscopy (ftir) this test was applied using (ir-affinity, shimazdo, japan) with a wave range between (400-4000)cm -1 at ibnsina state company / university of baghdad. 2.5. reactor the reactor is a stainless-steel tube with 2cm inside diameter, 2mm wall thickness, and 62 cm length. it was packed with 44.4 cm 3 of the catalyst between two layers of the inert glass ball. the reactor is heated and controlled automatically by four steel-jacket heaters (sotelem, rueil, france, 250 watt). for measuring the temperature of the catalyst and heaters, chromal alumel thermocouples (type k) fixed inside the reactor at three different locations were used to measure the temperature in the reactor. 2.6. isomerization process 44.4 cm 3 of fresh catalyst was charged to the reactor between two layers of inert materials (glass balls). the catalyst was then reduced with hydrogen at 350 º c for 3hours in the reactor [20]. after that, the charged reactor was flushed with nitrogen to purge the air from the system. meanwhile, the reactor is heated to the desired temperature. after reaching the reaction temperature, the nitrogen valve was closed. a pre-specified flow rate of n-decane was set on, vaporization of the feed occurs in the evaporator, and the vapor of n-decane mixed with the hydrogen in the mixing section at specified flow rates. the mixture entered the reactor from the top, distributed uniformly, and reacted on the catalyst charged inside the reactor. the product gases passed through the condenser and the final condensates were collected only after steady state operation was established and initial products were discarded. pt zr w/sapo-11 catalysts were used for kinetic study, the isomerization reaction conditions employed are temperatures of (200-275)ºc, the liquid hourly space velocity of 0.5-2h -1 , hydrogen to n-decane mole ratio of 2.1-8.2 and finally, the pressure was kept atmospheric. while the isomerization reaction conditions for base oil were employed at temperature (200-300)ºc, the liquid hourly space velocity of 0.5-2h -1 and the pressure kept atmospheric. fig. 1 shows the process flow diagram fig. 1. the catalytic hydro-conversion unit process flow diagram a. gas chromotograph (gc)) the reaction product analysis was obtained at ibn-sina state company/ university of baghdad using a chromatographic analysis on packed model 438aa-vsa. b. kinematic viscosity test according to astm d, 446 [21] method kinematic viscosity of base oil was measured by using canonfenske (routine viscometer) of size number 300 for transparent liquid. c. pour point test according to astm d97, the standard method of testing the pour point, the pour point of base oils samples was measured. 3result and discussion 3.1. sapo-11 characterization a. x-ray diffraction fig. 2 shows the x-ray diffraction patterns of sapo-11 sample. the sample was hydrothermally crystallized at 190 °c. h. a. al-jendeel and h. q. hussein / iraqi journal of chemical and petroleum engineering 22,2 (2021) 17 26 20 fig. 2. x-ray diffraction of sapo-11 the purity of the prepared sapo-11 was tested after a comparison between 2ɵ and d-spacing of the prepared samples with 2ɵ and d-spacing which are synthesized by zhang et al., [22]. the comparisons indicate that the preparation method results are compatible with the crystal structure of sapo-11 zeolite with an average crystallinity of 114.2%. this concludes that the preparation method gives good synthesized originality of sapo-11. b. x-ray florescence the molar composition of sapo-11 molecular sieve after calcination is 1al2o3:0.93p2o5:0.414sio2 c. particle size of sapo-11 catalyst the atomic force microscopy (afm) method was used to find the average particle size of sapo-11 samples. the effects of aging and doubling the water content on the size of sapo-11 were studied. the results show that the average particle diameter was fallen from 132.65nm (without aging with double water content) to 57.39nm (24 h aging time with double water content), this means that using the aging process (double water contents for both sample) decrease the particle diameter 75.26 nm, while the average particle diameter was fallen from 149.35 nm (conventional method) to 132.65 nm (without aging with double water content), this means that increasing the water contents double (without aging for both samples) decrease the particle diameter 16.7 nm. it can conclude that the aging process has more effect on average particle size diameter than water contents, this is due to the increasing of nucleation rate and crystals growth during the aging process [23]. d. surface area and pore volume sapo-11 displays a larger surface area and pore volume (396.17 m 2 g -1 and 0.3159 cm 3 g -1 respectively) with double water at a temperature of 190°c with aging for 24 hr. these values (surface area and pore volume) in this research are higher than previous work which indicated that the surface area was 242.2 m 2 g -1 and pore volume 0.196 cm 3 g -1 [22]. the decline in particle size of zeolite crystals from the micro-level to nano-level resulted in a considerable rise in surface area, thus yielding more active sites. e. fourier infrared spectroscopy ftir ft-ir spectroscopy analysis of sapo-11 was executed to study the structure of the chemical bonds between molecules. ftir was used to investigate the nature and quantum of hydroxyl groups produced by si. the ft-ir spectra of pt zr w/sapo-11 is shown in fig. 3. sapo-11 sample has three bands at 3743, 3677, and 3625 cm -1 , the former two bands refer to si-oh, p-oh groups respectively. the third one represents the spectra of the prepared brønsted acid site and the bridge si-oh-al that describes the acid properties of the sample [26]. the band 1100 cm 1 attributed to the asymmetric stretch of o–p–o; 730 cm -1 arising from the symmetric stretch of o–p–o; 640 cm -1 due to the bend of double 6-ring; 575 cm -1 , 530 cm -1, and 480 cm -1 ascribed to the bend of po4, alo4, and sio4, respectively [26]. fig. 3. ft-ir of synthesized pt zr w/sapo-11 f. pyridine ftir ft-ir spectroscopy is a technique that is used for the sharpness of brønsted and lewis acid sites by adsorption of pyridine on the catalysts [24]. the ft-ir spectra of pyridine adsorbed on pt zr w/sapo-11 is shown in fig. 4. the intensity of the bands at 1550 and 1450 cm -1 was thought to be proportional to brønsted and lewis acid site concentrations, respectively. it is interesting to understand that the number of acid sites is not only affected by the amount of si incorporated into the framework, but also by the large external surface of the superfine particles which allow the acid sites to be bonded with pyridine molecules. 0 200 400 600 800 1000 1200 0 10 20 30 40 50 60 702 theta i n t e n s i t y 190°c h. a. al-jendeel and h. q. hussein / iraqi journal of chemical and petroleum engineering 22,2 (2021) 17 26 21 it is clear from this figure that the sample gave broad vibrational bands at 1455 cm ‒1 and 1545 cm ‒1 , from pyridine molecules, adsorbed on lewis (l) and brönsted (b) acid sites, respectively [21]. the band at 1490 cm ‒1 corresponds to pyridine molecules adsorbed on both l and b acid sites [21]. the absorbance peaks for pyridine molecules adsorbed on the l or b acid sites changed after the introduction of platinum and zirconium-tungsten because zirconium has a combined effect on the degree of hydration and increases the active acid sites (bronsted and lewis ) [25]. fig. 4. ft-ir of synthesized pt zr w/sapo-11 after pyridine adsorption 3.2. isomerization of n-decane model the activity of pt zr w/sapo-11 was tested for isomerization of n-decane at different temperatures (200275°) and lhsv (0.5-2 hr -1 ). a. effect of temperature in order to maximize the production of isomerization products and, simultaneously, minimize cracking, the isomerization of n-decane should be at a temperature below 300°c [26]. fig. 5 shows that the increase of the temperature of the isomerization process from 200°c to 275°c at a constant lhsv increases the rate of the conversion of n-decane because the isomerization reaction is an exothermic reaction. therefore, increasing the temperature leads to an increase in the forwarding reaction toward isomerization. this is in agreement with alhassani for which who found that increasing temperature to 300°c leads to increase in the isomers of light naphtha [15]. as an example, the conversion of n-decane using lhsv of 0.5 hr -1 on pt zr w/sapo-11 increase from 48.52% at 200°c to 66.73% at 275°c. however, zirconium has a combined effect of the degree of hydration and increases the active acid sites (bronsted and lewis), while tungsten increases the degree of hydration. fig. 5. conversion of n-decane at different temperature and lhsv on pt zr w/sapo-11 b. effect of lhsv fig. 6 depicts the changes of n-decane conversion as a function of contact time which is expressed by lhsv. as lhsv decreases the conversion increases. this means that increasing the residence time leads to plenty of contact time in the feedstock with the catalyst inside the reactor. all results indicate that low lhsv is favored for an isomerization process as long as higher space velocities conversions are lower unless the temperature is raised [9]. fig. 6. conversion of n-decane at different contact time on pt zr w/sapo-11 c. effect of zr-w promoters on the catalyst activity the effect of the mixture of zirconium and tungsten promoters on the activity of the prepared sapo-11 catalyst was studied at different lhsv and temperature ranges 200 – 275°c. fig. 7 shows a comparison in n-decane conversion, using two types of promoters on sapo-11, the first one pt/sapo-11 and the second using pt/zr/w/sapo-11. it can be seen that the presence of platinum together with an acid component raises the mechanism for paraffin isomerization [18]. 0 10 20 30 40 50 60 70 80 150 170 190 210 230 250 270 290 temperature °c c o n v e r s io n % lhsv=0.5 lhsv=1 lhsv=1.5 lhsv=2 0 10 20 30 40 50 60 70 80 0 0.5 1 1.5 2 2.5 lhsv (hr -1 ) % c o n v e r s io n 200°c 225°c 250°c 275°c h. a. al-jendeel and h. q. hussein / iraqi journal of chemical and petroleum engineering 22,2 (2021) 17 26 22 this figure shows that pt zr w/sapo-11 gives higher conversion rate which means that the addition of these promoters (0.51% zr and 1.1% w, which are measured by xrf), can enhance the catalyst activity. the increase in the transformation on pt zr w/sapo-11 may be due to enhancement of the acid sites due to the presence of promoters [27]. tungstate species also appeared to be more resistant to the loss of active sites during the catalytic cycle, therefore they are more stable and give strong catalysts [28], while the presence of platinum increases the hydrationdehydration reaction. on the other hand, zirconium is a combined effect of the degree of hydration and increases the active acid sites (bronsted and lewis) [27]. lee et al [30] found the maximum conversion using pt w/sapo-11 was 42% in comparison with our research; it can be seen that the conversion was higher. fig. 7. conversion of n-decane with different promoters at lhsv 1.5 hr -1 d. the reaction order with respect to n-decane due to the linear relationship between -raand ca, it can be found that the order of the reaction is a first-order reaction as shown in fig. 8. no significant change in the reaction order was detected when the temperature increases from 200-275ºc. fig. 8. relation between ra and ca for pt zr w/sapo11 the reaction rate constants (k) were calculated at different reaction temperatures according to the linear relation between –ra and ca. while table 1 shows the values of rate constants that were obtained at different reaction temperatures. table 1. values of rate constant at different reaction temperatures reaction temperature (°c) k (liters /hr.kg catalyst) pt/zr/w/sapo-11 200 23.858 225 47.967 250 91.163 275 147.36 e. the apparent activation energy measurements the activation energy of isomerization reaction was calculated using arrhenius equation, which satisfies the relationship between rate constant and the reaction temperature. rt ea aek   (1) the plot of (ln k) vs. (1/t) was used for the calculation of the activation energy for the isomerization reaction and it was equal to 52.727 kj/mol. f. isodewaxing process for iraqi base oil isodewaxing is a process for making a base oil of a low pour point, high viscosity index, and improved oxidation stability. it is important to find the benefits of this invention in dewaxing process to study the effect of temperature before the cracking becomes excessive. f.1. effect of operating conditions on pour point temperature and lhsv have an obvious influence on the pour point of base oil (side stream comes from furfural extraction). as shown in fig. 9 and fig. 10 by increasing the space velocity (less contact time), the pour point increases at a constant temperature which means that an increase in the residence time, leads to plenty of contact time of the feedstock with the catalyst inside the reactor [10]. it can be concluded that when the temperature increases the pour point decreases however at moderate temperatures there is a chance for a hydroisomerization reaction to occur, resulting in an isoparaffin formation which has a low pour point (-16 °c at isomerization temperature of 300°c and lhsv 0.5 h -1 ) . this conclusion was supported by thomas et al., [30] . 0 10 20 30 40 50 60 150 170 190 210 230 250 270 290 te mpe rature °c c o n v e rs io n % pt/sapo-11 zr/w/pt/sapo-11 0 75 150 225 300 375 450 525 1.5 2 2.5 3 3.5 4ca(mol/liter) r a ( m o l/ h r .k g c a t 200°c 225°c 250°c 275°c h. a. al-jendeel and h. q. hussein / iraqi journal of chemical and petroleum engineering 22,2 (2021) 17 26 23 fig. 9. effect of temperature on pour point at various lhsv for pt/sapo-11 fig. 10. effect of temperature on pour point at various lhsv for pt zr w/sapo-11 f.2. effect of zr-w promoters on pour point the effect of the mixture of zirconium and tungsten promoters on pour point at different lhsv and temperature range 200 – 300°c were studied. a comparison for hydroisomerization of lubricating oil using two types of promoters on sapo-11, the first one pt/sapo-11 and the second using pt zr w/sapo-11 shows that pt zr w/sapo-11 gives a lower point (reducing pour point from -13°c by using pt/sapo-11 to -16°c when using pt zr w/sapo-11) which means that the addition of these promoters (0.51% zr and 1.1% w, which measured by xrf) can enhance the catalyst activity[31]. f.3. effect of operating conditions on viscosity index viscosity index is one of the most common properties of lube oil fractions. this property reflects the ability of the lube oil viscosity to vary with temperature. fig. 11 and fig. 12 investigates the variation of vi with operating conditions (catalyst bed temperature and lhsv) and the effect of zr/w promoters. it is obvious that the viscosity index increases with the catalyst bed temperature increasing and lhsv decreasing, for a given catalyst. the effect of the feed quality (aromatic and saturated content) also affects vi, and it has a strong relationship with the aromatics and saturates. the temperature increasing will encourage the saturation of aromatic species or even decomposition resulting in the conversion of aromatics to paraffinic or the conversion of alkanes to isoalkanes. this influence was in agreement with thomas et al [28] which indicates that the increase of a reaction temperature leads to an increase in the rate of isomerization while the lhsv decreasing leads to an increase in the time of contact and gives the same results. gortesema et al [29] and miller [3] obtained that the catalyst impregnated by platinum gives the best result for both viscosity index and pour point. it can be observed that using zirconium and tungsten promoters has the highest effect on vi and pouring point when compared with platinum alone. fig. 11. effect of temperature on vi at various lhsv for pt/sapo-11 fig. 12. effect of temperature on vi at various lhsv for pt zr w/sapo-11 -15 -10 -5 0 5 10 15 20 25 30 175 195 215 235 255 275 295 315 temperature,° c p o u r p o in t ,° c lhsv 0.5 lhsv 1 lhsv 1.5 lhsv 2 -20 -15 -10 -5 0 5 10 15 20 175 195 215 235 255 275 295 315 temperature , °c p o u r p o in t , ° c lhsv 0.5 lhsv 1 lhsv 1.5 lhsv 2 80 90 100 110 120 130 150 200 250 300 350 temperature °c v is c o s it y i n d e x lhsv 0.5 lhsv 1 lhsv 1.5 lhsv 2 80 90 100 110 120 130 140 150 200 250 300 350 temperature °c v is c o s it y i n d e x lhsv 0.5 lhsv 1 lhsv 1.5 lhsv 2 h. a. al-jendeel and h. q. hussein / iraqi journal of chemical and petroleum engineering 22,2 (2021) 17 26 24 4conclusion n-decane conversion increases as the temperature is increasing from 200 to 275°c and decreases as the lhsv is increasing from 0.5 to 2 hr -1 . the highest n-decane conversion was56.77% which was achieved at 275°c and 0.5 hr -1 lhsv, while the reaction order was first order. while isodewaxing of 3ss base oil was achieved and the flow properties of the base oil were improved. the best isodewaxing conditions were a temperature of 300°c and lhsv 0.5 h -1 . the pour point of base oil was reduced to -16°c, while the viscosity index was improved to 134.8 by using pt zr w/sapo-11. acknowledgment the authors wish to extend their gratitude to the chemical engineering department, university of bagdad "iraq" for their solid support which made this work realized. symbols symbol definition unit a pre-exponential factor for 1 st order reaction :min -1 ca the concentration of decane at any time mol/liter ea activation energy kj/mol k reaction rate constant liters/h.kg catalyst references [1] tian s. and chan j. "hydroisomerization of ndodecane on an new kind of bifunctional catalyst:nickel phosphide supported on sapo-11 molecular sieve", fuel processing technology 122,2014,120-128. [2] wang z, tian z, teng f, wen g, xu y, xu z, lin l, "hydro isomerization of long-chain alkane over pt/sapo-11 catalysts synthesized from nonaqueous media". catal lett 103, 2005, 109–116. [3] miller s.j., " studies on wax isomerization for lubes and fuels" . studies in surface science and catlylsts, 84, 1994, 2319–2326. [4] song h.,liu z ., xing w., ma z., yan z. zhao l., zhang z., gao x., "preparation of hierarchical sapo-11 molecular sieve and its application for ndodecane isomerization", appl petrochem res, 2014, 4:401–407 [5] krishna k.r., rainis, a., marcantonio,p.j., mayer p.j., chevron l., biscardi j.a., "next generation isodewaxing and hydrofinshing technology for prodection of high quality base oils", 2002 npra lubricants and waxes meeting ,november 14-15, 2002,omni hotel houston, texas. [6] h.deldari, stud"suitable catalysts for hydroisomerization of long-chain normal paraffins",. applied catalysis a, 239,2005, 1-10. [7] robert j. taylor, randall h. petty," selective hydroisomerization of long chain normal paraffins", applied catalysis a , 119, 1994, 121-138. [8] nieminen v., kumar n., heikkila t., laine e., villegas j., salmi t., and murzin d.y.,"isomerization of 1-butene over sapo-11 catalysts synthesized by varying synthesis time and silica sources", applied catalysis a, 259,2004,227-234. [9] abdul halim a.k. m.,,rahman a.m., and al-hassani m.," kinetic study of catalytic hexane isomerization", , ijcpe vol.10 ,no.1 ,2009,17-22. [10] lok b.m., messina c.a. ,patton r.l. , gajek r.t., cannan t.r. and flanigen e.m.. "crystalline silicoaluminophosphates" us.patent, 4440871, 1984. [11] shengzhen zhang, sheng-li chen peng dong, zhiyong ji, junying zhao, and keqi xu , "synthesis, characterization and hydroisomerization catalytic performance of nanosize sapo-11 molecular sieves" , catalysis letters, vol. 118,2007, p. 109-117. [12] sastre g., chica a., and corma a. "on the mechanism of alkane isomerization (isodewaxing) with unidirectional 10member ring zeolites. a molecular dynamics and catalytic study", journal of catalysis 195, 2000, 227-236. [13] zhipeng ma, zhen liu,hao song,peng bai,wei xing, zifeng yan, lianhog zhao, zhongdong zhang and xionghou gao, " synthesis of hierarchical sapo11 for hydroisomerization reaction in refinery processes, appl petrochem.res ,vol 4 (2014),351-358. [14] cui x., liu y., and liu x., "controlling acidic sites to improve hydroisomerization performance of pt/sapo-11 catalysts", catal lett, 145(2015), 14641473. [15] sinha a. k. , sivasanker s. , and ratnasamy p., " hydroisomerization of n-alkanes over pt-sapo-11 and pt-sapo-31 synthesized from aqueous and nonaqueous media", ind. eng. chem. res. 37,1998, 2208-2214. [16] al-hassany m., " effect zro2 , wo3 additives on catalytic performance of pt/hy zeolite compared with pt/γ-al2o3 for iraqi naphtha transformation", journal of enginnering, vol. 15, number 4,2009,43784394. [17] zheming wang, zhijian tian, fei teng, guodong wen, yunpeng xu, zhusheng xu and liwu lin," hydroisomerization of long-chain alkane over pt/sapo-11 catalysts synthesized from nonaqueous media",catalysis letters, vol.103 (2005), 109-116. [18] hussein q. h. and aljandeel h.a.," studying influence of aging and crystallization temperature on characteristics of sapo-11 catalyst using hydrothermal method", 1 st international conference on recent trends of engineering sciences and sustainability, 2017. [19] masologites., george, "method of treating a used pt group alumina catalyst with a metal promoter", us patent, 4070306, 1978. [20] chang c.d. , princeton n.j., jose g., sontiesteban, david l., stern, "isomerization process", us patent, 6080904, 2000. https://www.sciencedirect.com/science/article/pii/s0378382014000411 https://www.sciencedirect.com/science/article/pii/s0378382014000411 https://www.sciencedirect.com/science/article/pii/s0378382014000411 https://www.sciencedirect.com/science/article/pii/s0378382014000411 https://www.sciencedirect.com/science/article/pii/s0378382014000411 https://link.springer.com/article/10.1007/s10562-005-6510-x https://link.springer.com/article/10.1007/s10562-005-6510-x https://link.springer.com/article/10.1007/s10562-005-6510-x https://link.springer.com/article/10.1007/s10562-005-6510-x https://www.sciencedirect.com/science/article/abs/pii/s0167299108637969 https://www.sciencedirect.com/science/article/abs/pii/s0167299108637969 https://www.sciencedirect.com/science/article/abs/pii/s0167299108637969 https://link.springer.com/article/10.1007/s13203-014-0081-y https://link.springer.com/article/10.1007/s13203-014-0081-y https://link.springer.com/article/10.1007/s13203-014-0081-y https://link.springer.com/article/10.1007/s13203-014-0081-y https://link.springer.com/article/10.1007/s13203-014-0081-y http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.550.2885 http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.550.2885 http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.550.2885 http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.550.2885 http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.550.2885 http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.550.2885 https://www.sciencedirect.com/science/article/abs/pii/s0926860x05004953 https://www.sciencedirect.com/science/article/abs/pii/s0926860x05004953 https://www.sciencedirect.com/science/article/abs/pii/s0926860x05004953 https://www.sciencedirect.com/science/article/abs/pii/0926860x94850291 https://www.sciencedirect.com/science/article/abs/pii/0926860x94850291 https://www.sciencedirect.com/science/article/abs/pii/0926860x94850291 https://www.sciencedirect.com/science/article/abs/pii/s0926860x03008391 https://www.sciencedirect.com/science/article/abs/pii/s0926860x03008391 https://www.sciencedirect.com/science/article/abs/pii/s0926860x03008391 https://www.sciencedirect.com/science/article/abs/pii/s0926860x03008391 https://www.sciencedirect.com/science/article/abs/pii/s0926860x03008391 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/393 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/393 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/393 https://pubs.acs.org/doi/pdf/10.1021/ja00332a063 https://pubs.acs.org/doi/pdf/10.1021/ja00332a063 https://pubs.acs.org/doi/pdf/10.1021/ja00332a063 https://link.springer.com/article/10.1007/s10562-007-9138-1 https://link.springer.com/article/10.1007/s10562-007-9138-1 https://link.springer.com/article/10.1007/s10562-007-9138-1 https://link.springer.com/article/10.1007/s10562-007-9138-1 https://link.springer.com/article/10.1007/s10562-007-9138-1 https://www.sciencedirect.com/science/article/abs/pii/s0021951700930021 https://www.sciencedirect.com/science/article/abs/pii/s0021951700930021 https://www.sciencedirect.com/science/article/abs/pii/s0021951700930021 https://www.sciencedirect.com/science/article/abs/pii/s0021951700930021 https://www.sciencedirect.com/science/article/abs/pii/s0021951700930021 https://link.springer.com/article/10.1007/s13203-014-0071-0 https://link.springer.com/article/10.1007/s13203-014-0071-0 https://link.springer.com/article/10.1007/s13203-014-0071-0 https://link.springer.com/article/10.1007/s13203-014-0071-0 https://link.springer.com/article/10.1007/s13203-014-0071-0 https://link.springer.com/article/10.1007/s10562-015-1554-z https://link.springer.com/article/10.1007/s10562-015-1554-z https://link.springer.com/article/10.1007/s10562-015-1554-z https://link.springer.com/article/10.1007/s10562-015-1554-z https://pubs.acs.org/doi/abs/10.1021/ie9707228 https://pubs.acs.org/doi/abs/10.1021/ie9707228 https://pubs.acs.org/doi/abs/10.1021/ie9707228 https://pubs.acs.org/doi/abs/10.1021/ie9707228 https://pubs.acs.org/doi/abs/10.1021/ie9707228 https://www.iasj.net/iasj/download/2d5b8ac791de845f https://www.iasj.net/iasj/download/2d5b8ac791de845f https://www.iasj.net/iasj/download/2d5b8ac791de845f https://www.iasj.net/iasj/download/2d5b8ac791de845f https://www.iasj.net/iasj/download/2d5b8ac791de845f https://link.springer.com/article/10.1007/s10562-005-6510-x https://link.springer.com/article/10.1007/s10562-005-6510-x https://link.springer.com/article/10.1007/s10562-005-6510-x https://link.springer.com/article/10.1007/s10562-005-6510-x https://link.springer.com/article/10.1007/s10562-005-6510-x https://patents.google.com/patent/us4070306a/en https://patents.google.com/patent/us4070306a/en https://patents.google.com/patent/us4070306a/en h. a. al-jendeel and h. q. hussein / iraqi journal of chemical and petroleum engineering 22,2 (2021) 17 26 25 [21] american, n. s., 1979. standard specifications and operating instructions for glass capillary kinematic viscomrters. d446-74, deutsche norm din 366 und 51372 [22] zhang s., chen s., dong p.,ji z.,zhao j. and xu k., "synthesis, characterization and hydroisomerization catalytic performance of nanosize sapo-11 molecular sieves" , catalysis letters, vol. 118, p. 109-117, 2007. [23] zhang f., liu y., shu x., wang w. and qin f. , " sapo-11 molecular sieve, its synthetic method and a catalyst containing the molecular sieve", us patent, 6596156, 2003. [24] marjan r., rouein h., and sima a., " recent advances in silicoaluminophosphate nanocatalysts synthesis techniques and their effects on particle size distribution", rev.adv.mater.sci. 29, 83-99, 2011. [25] liu y.,guan y.,li c., juan l.,geok j., eng chew, fethi k.,"effect of zno additives and acid treatment on catalytic performance of pt/w/zr for heptane isomerization,"j. of cat.244, 2006,17-23. [26] aljandeel h.a., hussein h.q.," kinetic study of hydroisomerization of n-decane using pt/sapo11 catalysts", iraqi journal of chemical and petroleum engineering 2018, 19(3), 11-17. https://doi.org/10.31699/ijcpe.2018.3.2 [27] risch m.,wolf e., "effect of the preparation of a mesoporous sulfated zirconia catalyst in n-butane isomerization activity", applied catalysis a: general 206 (2001) 283–293. [28] thommes m., "physical adsorption characterization of nanoporous materials", chemie ingenieur technik , 82, no. 7, 2010. [29] gortsema,f.p.,pellet,r.j., springer, a.r., rabo,j.a., armonk, long,g.n., " hydrocracking catalysts and processes employing non zeolitic molecular sieves", u.s.patent no. 4818739,1989. [30] lee e., yun s. , park y.k. , jeong s.y. , han j., jeon j.k., "selective hydroisomerization of ndodecane over platinum supported on sapo-11", journal of industrial and engineering chemistry, 20, 2014, 775-780. [31] oliveira, l., nunes, r., ribeiro, y., coutinho, d., azevedo, d., dias, j., & lucas, e. ,"wax behavior in crude oils by pour point analyses". journal of the brazilian chemical society.2018, 29(10),21582168. doi:10.21577/0103-5053.20180092 https://link.springer.com/article/10.1007/s10562-007-9138-1 https://link.springer.com/article/10.1007/s10562-007-9138-1 https://link.springer.com/article/10.1007/s10562-007-9138-1 https://link.springer.com/article/10.1007/s10562-007-9138-1 https://link.springer.com/article/10.1007/s10562-007-9138-1 https://patents.google.com/patent/us6596156b1/en https://patents.google.com/patent/us6596156b1/en https://patents.google.com/patent/us6596156b1/en https://patents.google.com/patent/us6596156b1/en https://www.sciencedirect.com/science/article/abs/pii/s0021951706002995 https://www.sciencedirect.com/science/article/abs/pii/s0021951706002995 https://www.sciencedirect.com/science/article/abs/pii/s0021951706002995 https://www.sciencedirect.com/science/article/abs/pii/s0021951706002995 https://doi.org/10.31699/ijcpe.2018.3.2 https://doi.org/10.31699/ijcpe.2018.3.2 https://doi.org/10.31699/ijcpe.2018.3.2 https://doi.org/10.31699/ijcpe.2018.3.2 https://doi.org/10.31699/ijcpe.2018.3.2 https://www.sciencedirect.com/science/article/abs/pii/s0926860x00006074 https://www.sciencedirect.com/science/article/abs/pii/s0926860x00006074 https://www.sciencedirect.com/science/article/abs/pii/s0926860x00006074 https://www.sciencedirect.com/science/article/abs/pii/s0926860x00006074 https://onlinelibrary.wiley.com/doi/abs/10.1002/cite.201000064 https://onlinelibrary.wiley.com/doi/abs/10.1002/cite.201000064 https://onlinelibrary.wiley.com/doi/abs/10.1002/cite.201000064 https://patents.google.com/patent/us4913799a/en https://patents.google.com/patent/us4913799a/en https://patents.google.com/patent/us4913799a/en https://patents.google.com/patent/us4913799a/en https://www.sciencedirect.com/science/article/abs/pii/s1226086x13002505 https://www.sciencedirect.com/science/article/abs/pii/s1226086x13002505 https://www.sciencedirect.com/science/article/abs/pii/s1226086x13002505 https://www.sciencedirect.com/science/article/abs/pii/s1226086x13002505 https://www.sciencedirect.com/science/article/abs/pii/s1226086x13002505 https://www.scielo.br/j/jbchs/a/txrm8ndj5d45r5lt3fz77jd/?lang=en https://www.scielo.br/j/jbchs/a/txrm8ndj5d45r5lt3fz77jd/?lang=en https://www.scielo.br/j/jbchs/a/txrm8ndj5d45r5lt3fz77jd/?lang=en https://www.scielo.br/j/jbchs/a/txrm8ndj5d45r5lt3fz77jd/?lang=en https://www.scielo.br/j/jbchs/a/txrm8ndj5d45r5lt3fz77jd/?lang=en h. a. al-jendeel and h. q. hussein / iraqi journal of chemical and petroleum engineering 22,2 (2021) 17 26 26 الى لعمليات االزمرة pt/sapo-11دراسة متقدمة للعامل المساعد المحفز الهيدروجينية للديكان الطبيعي و زيت التشحيم رشيد و حسين قاسم حسين حيدر عبد الكريم جامعة بغداد/ كلية الهندسة الخالصة . من السليكا , وااللومينا والفوسفيت بوجود البروبايل اماين كقالب sapo-11تم تصنيع العامل المساعد /غم , حجم 2م 396اظهرت النتائج ان النموذج الذي تم تصنيعه لديه درجة تبلور جيدة, مساحة سطحية لقد تم pt (1)zr (0.5)w/sapo-11(0.25)/غم . ان فعالية االزمرة للعامل المساعد 3سم 0.35المسامات م ومعدل °275-°200ايجادها بوجود الديكان وزيت االساس في مفاعل ذو الحشوة الثابتة في درجات حرارة . لقد اظهرت النتائج ان نسبة التحول تزداد بزيادة درجة الحرارة ونقصان معدل الجريان. ان 1-سا2-0,5جريان . في حين تم استعمال 1-سا0,5م و معدل جريان °275% وجدت عند درجة حرارة 66,7اعلى نسبة تحول هي ادة معامل اللزوجة وتقليل نقطة االنسكاب , حيث تمت نفس العامل المساعد لتحسين مواصفات زيت االساس بزي ان هذه الدراسة بينت ودون تغيير الضغط. 1-سا2-0,5ومعدل جريان م °300-200العملية في درجات حرارة م في °16-قد خفضت نقطة االنسكاب الى sapo-11ان البالتين ,الزركونيوم والتنكستن المحملة على . 134,8ومؤشر لزوجة 1-سا0,5ريان م ومعدل ج°300درجة حرارة , ازمرة , ديكان , محفزات ثنائية, زيت التشحيم, نقطة االنسكاب, مؤشر اللزوجة 11-: سابوالدالةالكلمات available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.23 no.1 (march 2022) 15 – 22 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: miqat hasan salih, email: mekat.hassan@coeng.uobaghdad.edu.iq, name: ahmed faiq al-alawy, email: drahmed@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. crystallization process as a final part of zero liquid discharge system for treatment of east baghdad oilfield produced water miqat hasan salih and ahmed faiq al-alawy chemical engineering department, college of engineering, university of baghdad, baghdad, iraq. abstract this study investigated the application of the crystallization process for oilfield produced water from the east baghdad oilfield affiliated to the midland oil company (iraq). zero liquid discharge system (zld) consists of several parts such as oil skimming, coagulation/flocculation, forward osmosis, and crystallization, the crystallization process is a final part of a zero liquid discharge system. the laboratory-scale simple evaporation system was used to evaluate the performance of the crystallization process. in this work, sodium chloride solution and east baghdad oilfield produced water were used as a feed solution with a concentration of 177 and 220 g/l. the impact of temperature (70, 80, and 90 °c), mixing speed (300, 400, and 500 rpm), feed concentration (177 and 220 g/l), and time (0.5-9.5 h) on the crystallization performance for oilfield produced water treatment were investigated on evaporation rate and recovery. the recovery increased with increasing temperature and mixing speed while decreasing with an increase in feed concentration. pure water and salts were recovered from the concentrated produced water, the recovery of pure water at 80 °c, 400 rpm, and 220 g/l feed concentration was 82.22 and 81.35% after 5.5 h for nacl solution (i.e., simulated oilfield produced water) and oilfield produced water, respectively. keywords: crystallization, evaporation, zero liquid discharge system, iraqi oilfield produced water. received on 03/02/2022, accepted on 22/02/2022, published on 30/03/2022 https://doi.org/10.31699/ijcpe.2022.1.3 1introduction the public and industrial sectors consume a large amount of freshwater while producing a large amount of wastewater [1]. various desalination technologies have been developed in recent decades to alleviate water scarcity [2]. the oil industry is a major source of pollutants that pollute the environment, having the ability to affect it at all levels: air, water, soil, and, as a result, all living beings on earth [3, 4]. iraq's oilfields are dispersed over vast areas. water-to-oil ratios in oil fields, particularly in southern and northern iraq, may reach 20%. in the near future, this ratio may reach the global average [5]. iraq is one of the world's most important oilproducing countries, with the third largest proven oil reserves and the world's second largest oil exporter [6]. produced water may contain various compounds including suspended solids [7], volatile organic compounds, dissolved solids [8], heavy metals, chemical additives like coagulants [6], scale inhibitors [9], free and dispersed oil and grease, microorganisms [10]. to produce high-quality treated water, a series of different technologies must be combined [11]. hence, novel strategies for reusing produced water must be developed to address the problem of water scarcity [12]. treated water has the potential to be a valuable product rather than a waste [10]. zero liquid discharge (zld) is an ambitious wastewater management strategy that uses cost-effective methods to concentrate brine to near or complete dryness, with the majority of water recovered for reuse [13]. zero liquid discharge desalination is regarded as a solution to the brine disposal problem because it produces only solid salts byproducts and clean water from the source water [14]. zld eliminates the risk of pollution associated with wastewater discharge and maximizes water usage efficiency, achieving a balance between freshwater resource exploitation and aquatic environment preservation [15]. due to stringent discharge standards, zld is sometimes the only way to ensure regulatory compliance [16]. mechanical vapor compression (mvc)-based brine concentrators and crystallizers are the most widely used technologies in zld. brine concentrators based on membrane processes such as forward osmosis and membrane distillation have recently received a lot of attention due to their ability to use low-grade heat as an energy source [17]. a pretreatment step is required to improve membrane performance in zld. coagulation, chemical precipitation, adsorption, flotation, advanced oxidation, and electrocoagulation are the most common pre-treatment processes in the industry today [16]. fig. 1 shows some processes in a zero liquid discharge system. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:mekat.hassan@coeng.uobaghdad.edu.iq mailto:drahmed@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2022.1.3 m. h. salih and a. f. al-alawy / iraqi journal of chemical and petroleum engineering 23,1 (2022) 15 22 16 fig. 1. the processes of a zld system with membrane and thermal treatment [16] crystallization is an important mass transfer operation that is frequently used in the manufacture of a pure product. during the process, a crystal usually is separated as a substance of definite composition from a solution of varying composition. a state of imbalance including a mass driving force, particularly a decrease in chemical potential (or concentration) between the bulk of the liquid solution and the crystal interface is required for the separation of a solid from a solution onto a crystal. as a result, the solution must be supersaturated. although crystallization is commonly defined as the formation of a solid crystalline phase from a liquid phase via cooling, evaporation, or both [18]. crystals have been produced throughout the history of the chemical industry using crystallization methods ranging from as simple as allowing vats of hot concentrated solution to cool to as complex as continuous, precisely controlled, multi-step processes that result in a crystal product with a specific size or size distribution, moisture content, shape, and purity [19, 20]. crystallization can be done at high or low temperatures, and it generally requires less energy to separate pure materials than other commonly used purification methods [21]. evaporation is a common process used in both water desalination and other feed stream treatment. it can be used to treat a wide range of feeds, including liquids, slurries, sludges, organic and inorganic streams, suspended or dissolved solids, and nonvolatile dissolved liquids [19]. evaporation is used to concentrate a solution that contains a nonvolatile solute and a volatile solvent. the solvent in the vast majority of evaporations is water. evaporation is accomplished by vaporizing a portion of the solvent, resulting in a concentrated solution of thick liquor. in a saturated mother liquor, evaporation can result in a slurry of crystals [22]. the primary goal of evaporation in some cases is concentrating the solution so that when it cools, salt crystals form and are separated. this type of evaporation is known as crystallization [20]. evaporation is one of the simplest methods for crystallizing organic, inorganic, and organometallic small molecule compounds [23]. in an evaporative crystallizer, crystallization takes place by evaporating the solvent from feed, which can be either a weak unsaturated solution or a hot concentrated mixture. when the temperature-solubility curve of a solute has a low slope, these crystallizers are used [19]. when the solution or mother liquor is saturated, equilibrium is reached in crystallization and this could be represented by a solubility curve. the temperature has the greatest influence on solubility. the effect of pressure on solubility is negligible [20, 24]. the solubilities of common salts in water as a function of temperature are depicted in fig. 2. in most cases, the solubility of the salt increases with temperature. this means that when a hot concentrated solution from an evaporator is cooled to room temperature, crystallization may occur [20]. nacl's solubility is characterized by a small temperature change. this means that the nacl solution was evaporated at a constant temperature until crystals formed [19, 20]. the most common brine treatment technologies in a zld system are brine concentrators and brine crystallizers [25, 26]. in our previous work salih et al. [27] and salih and al-alawy [28], the treatment of oilfield produced water from the east baghdad oilfield with tds = 86 g/l using three stages of the zld system namely oil skimming, coagulation/flocculation, and forward osmosis processes were studied. the best temperature and time for oil skimming were 40 °c and 2.5 h. which gave 95.8% removal for oil content. in the coagulation/flocculation process, the optimum pac dosage and ph were 55 mg/l and 6.4 which gave 99.9% and 97.7% removal for oil content and tss, respectively. after the coagulation and flocculation process, the tds of produced water reduced to 76 g/l. in the fo process, sodium chloride solution was used as a feed solution (fs) with a concentration of 76 g/l, while the draw solution (ds) was magnesium chloride. the produced water feed solution was concentrated to 220 g/l at ds concentration of 400 g/l mgcl2 in batch mode with a constant ds concentration after 16.5 h at which the recovery was 65.67%. this concentrated solution is considered waste and needs to be disposed of, which violates environmental regulations. if this concentrated solution is considered as waste, this does not achieve the zero liquid discharge system, which is known to end without waste. therefore, to complete the process of the zero s liquid discharge system and recover all pure water and salts, we need to a final stage, which is crystallization. this research aims to apply a crystallization process by simple evaporation to generate clean water and solid salts with no waste to attain zero liquid discharge system. the efficiency of the crystallization process will be estimated with different temperatures, mixing speeds, time, and concentrations of nacl solution and oilfield produced water from the east baghdad oilfield. the possibility of using an evaporation process to generate pure water and solid salts will be investigated with regard to evaporation rate and recovery. m. h. salih and a. f. al-alawy / iraqi journal of chemical and petroleum engineering 23,1 (2022) 15 22 17 fig. 2. solubility curves for some typical salts in water [20] 2experimental work two types of feed were used: the first was nacl solution (i.e., simulated oilfield produced water), and the second was oilfield produced water based on the concentrated feed from the forward osmosis process. nacl (99%, india) was used to prepare a feed solution that has the same tds as the east baghdad oilfield produced water, the distilled water of conductivity 1.7 µs/cm was used to prepare the nacl solution. the properties of oilfield produced water are listed in table 1. table 1. properties of oilfield produced water from the east baghdad oilfield after forwarding osmosis process characteristics value tds, mg/l 220000 ca+2, mg/l 11700 mg+2, mg/l 7475.045 so4 −2, mg/l 654.661 cl−1, mg/l 119464.21 na+1, mg/l 76500 the crystallization process was performed in a beaker of a capacity of 100 ml. each beaker was filled with 100 ml of the produced water. all experiments were carried out under magnetic stirring at different mixing speeds (300, 400, and 500 rpm), different temperatures (70, 80, and 90 °c) measured by a thermometer, and time (0.5-9.5 h). different concentrations (177 and 220 g/l) of the concentrated produced water from the fo process were examined. all experiments continue until most of the water evaporates leaving only salt as solid crystals and weighted by a balance. the rate of evaporation can be calculated as follows [29]: 𝑅𝑎𝑡𝑒 𝑜𝑓 𝐸𝑣𝑎𝑝𝑜𝑟𝑎𝑡𝑖𝑜𝑛 = ∆𝑊 ∆𝑡 (1) where: ∆w is the water evaporated over time ∆t. the recovery of pure water measures how much of the feed water is recovered. recovery was determined by using equation 2 [30]: %𝑅𝑒𝑐𝑜𝑣𝑒𝑟𝑦 = ( 𝑉𝑃 𝑉𝐹 ) ∗ 100 (2) where: vp is the volume of water evaporated and vf is the volume of water in the feed vessel. table 2 represents the range of the operating conditions and variables examined in the evaporation and crystallization processes. table 2. operating condition for crystallization process operating conditions crystallization tests feed solution, fs simulated and real east baghdad oilfield produced water mixing speed 300, 400, and 500 rpm temperature of feed solution, t 70, 80, and 90 °c feed solution concentration, cf 177 and 220 g/l time, t 0.5-9.5 h 3results and discussions the evaporation rate and recovery were measured in the crystallization process with three evaporation temperatures (70, 80, and 90 °c). as shown in fig. 3, the evaporation rate increased with temperature rise and decreased with time. for t=90 °c, the evaporation rate reached 16.56 g/h after 2.75 h of operation, for t= 80 °c the evaporation rate reached 12.64 g/h after 5.5 h of operation while reached to 8.2 g/h after 9.5 h of operation for t= 70 °c. fig. 4 shows the recovery of pure water raised with temperature and time. the recovery reached 77.33% after 2.5 h of operation for t=90 °c, for the same time (t= 2.5 h) the recovery of t=80 and 70 °c were lower than that of 90 °c by 44.65%, and 69.48% respectively. heating the liquids causes more molecules of the liquid to gain enough kinetic energy to move faster and change to vapor. because a molecule's kinetic energy is proportional to its temperature, evaporation occurs more quickly at higher temperatures. the higher the temperature, allowing molecules to escape from the surface of a liquid, this means the molecules near the surface have higher chemical potential (escape tendency) than other molecules in the liquid. when the liquid molecules collide, they transfer energy to each other based on how they collide. when a molecule near the surface absorbs enough energy to overcome the vapor pressure, it escapes and becomes vapor in the surrounding air. this increases the rate of evaporation and recovery. these findings are supported by those obtained by misyura [24]. m. h. salih and a. f. al-alawy / iraqi journal of chemical and petroleum engineering 23,1 (2022) 15 22 18 fig. 3. evaporation rate as a function of time for simulated pw as fs (cfs,i=220 g/l, mixing speed=400 rpm) fig. 4. recovery of pure water as a function of time for simulated pw as fs (cfs,i=220 g/l, mixing speed=400 rpm) the evaporation rate and recovery were measured in the crystallization process with three mixing speeds (300, 400, and 500 rpm). as shown in fig. 5, the evaporation rate increased with rising mixing speed and decreased with time. for mixing speed=500 rpm, the evaporation rate reached 13.36 g/h after 5 h of operation, for mixing speed=400 rpm the evaporation rate reached 12.64 g/h after 5.5 h of operation while reached 12.52 g/h after 6 h of operation for mixing speed=300 rpm. fig. 6 shows the recovery of pure water raised with mixing speed and time. the recovery of pure water reached 81.63% after 5 h of operation for mixing speed=500 rpm, for mixing speed=400 rpm, the recovery reached 82.22% after 5.5 h of operation, while it reached 80.79% after 6 h of operation for mixing speed=300 rpm. the influence of mixing involves adding mechanical energy to a stable system. this mechanical energy is absorbed by the liquid being mixed as a result of billions of collisions between the stirrer and the liquid colliding with it, as well as other liquids. this energy is equivalent to heat, so the entire system is heating up. the molecules will break free from the liquid's bonds and fly away as vapor, i.e., vaporize, the higher the mixing speed, the greater the particle breakage which prevents particles from aggregating. therefore, an average mixing speed of 400 rpm was chosen. these findings are supported by those obtained by choi [21]. fig. 5. evaporation rate as a function of time for simulated pw as fs (cfs,i=220 g/l, t=80 °c) fig. 6. recovery of pure water as a function of time for simulated pw as fs (cfs,i=220 g/l, t=80 °c) the evaporation rate and recovery were measured in the crystallization process with two feed concentrations (177 and 220 g/l). as shown in fig. 7, the evaporation rate increased with decreasing feed concentration and time. for feed concentration=177 and 220 g/l, the evaporation rate reached 12.8 and 12.64 g/h, respectively after 5.5 h of operation. fig. 8 shows the recovery of pure water raised with time and decreased with increasing feed concentration. for the same time of 5.5 h, the recovery of the feed concentration=220 g/l was lower than that of 177 g/l by 3.16%. water activity decreases as the ion mass fraction (feed concentration) increases. this is due to a decrease in the chemical potential of the water. these findings are agreed with naillon et. al. [31]. 0 1 2 3 4 5 6 7 8 9 10 5 10 15 20 25 30 35 40 time, h e v a p o ra ti o n r a te , g /h t=70 °c t=80 °c t=90 °c 0 1 2 3 4 5 6 7 8 9 10 0 10 20 30 40 50 60 70 80 90 time, h r e c o v e ry , % t=70 °c t=80 °c t=90 °c 0 1 2 3 4 5 6 12 14 16 18 20 22 24 time, h e v a p o ra ti o n r a te , g /h mixing speed=300 rpm mixing speed=400 rpm mixing speed=500 rpm 0 1 2 3 4 5 6 0 10 20 30 40 50 60 70 80 90 time, h r e c o v e ry , % mixing speed=300 rpm mixing speed=400 rpm mixing speed=500 rpm m. h. salih and a. f. al-alawy / iraqi journal of chemical and petroleum engineering 23,1 (2022) 15 22 19 fig. 7. evaporation rate as a function of time for simulated pw as fs (t=80 °c, mixing speed=400 rpm) fig. 8. recovery of pure water as a function of time for simulated pw as fs (t=80 °c, mixing speed=400 rpm) the evaporation rate and recovery were measured in the crystallization process with three evaporation temperatures (70, 80, and 90 °c) for east baghdad oilfield produced water. as shown in fig. 9, the evaporation rate increased with temperature rise and decreased with time. the evaporation rate reached 16 g/h after 2.75 h of operation for t=90 °c, t, for t= 80 °c the evaporation rate reached 12.58 g/h after 5.5 h of operation while reached to 7.8 g/h after 9.5 h of operation for t= 70 °c. fig. 10 shows the recovery of pure water raised with temperature and time. for t=90 °c, the recovery reached 80.28% after 2.75 h of operation; for t= 80 °c, the recovery reached 80.95% after 5.5 h of operation, while it reached 80.49% after 9.5 h of operation for t= 70 °c. the recovery reached 76.28% after 2.5 h of operation for t=90 °c, for the same time, the recovery of the t=80 and 70 °c were lower than that of 90 °c by 44.4%, and 69.59% respectively. fig. 9. evaporation rate as a function of time for oilfield produced water as fs (cfs,i=220 g/l, mixing speed=400 rpm) fig. 10. recovery of pure water as a function of time for oilfield produced water as fs (cfs,i=220 g/l, mixing speed=400 rpm) fig. 11. recovery of pure water for pw (cf,i= 220 g/l, mixing speed=400 rpm) for crystallization process 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 12 13 14 15 16 17 18 19 20 21 time, h e v a p o ra ti o n r a te , g /h cf=177 g/l cf=220 g/l 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 10 20 30 40 50 60 70 80 90 time, h r e c o v e ry , % cf=177 g/l cf=220 g/l 0 1 2 3 4 5 6 7 8 9 10 5 10 15 20 25 30 35 40 time, h e v a p o ra ti o n r a te , g /h t=70 °c t=80 °c t=90 °c 0 1 2 3 4 5 6 7 8 9 10 0 10 20 30 40 50 60 70 80 90 time, h r e c o v e ry , % t=70 °c t=80 °c t=90 °c m. h. salih and a. f. al-alawy / iraqi journal of chemical and petroleum engineering 23,1 (2022) 15 22 20 fig. 11 shows a comparison between the oilfields produced water and nacl solution. at the end of each experiment the recovery at t=70, 80, and 90 °c for oilfield produced water is lower than that of nacl solution by 2.26, 1.55, and 1.46%, respectively. this simple difference in results is because the oilfield produced water contains a mixture of salts, not only nacl, but the largest proportion of the salts is nacl. 4conclusion this work shows that a crystallization process is an effective and viable option as a final part of a zero liquid discharge system for the treatment of high salinity oilfield produced water. the recovery for a temperature of 80 °c was 82.22 and 80.95% after 5.5 h for nacl solution and oilfield produced water, respectively. while for 90 °c the recovery was 81.47 and 80.28% for nacl solution and oilfield produced water after 2.75 h. the best mixing speed was moderate at 400 rpm. there is a small difference in the pure water recovery between nacl solution and oilfield produced water. acknowledgment the authors are grateful for the support of thabit abbas ahmed and the petroleum research and development center staff during the experimental work. references [1] a. f. al-alawy and m. h. salih, “experimental study and mathematical modelling of zinc removal by reverse osmosis membranes,” iraqi j. chem. pet. eng., vol. 17, no. 3, pp. 57–73, 2016. [2] k. j. lu, z. l. cheng, j. chang, l. luo, and t. s. chung, “design of zero liquid discharge desalination (zldd) systems consisting of freeze desalination, membrane distillation, and crystallization powered by green energies,” desalination, vol. 458, pp. 66–75, 2019, doi: 10.1016/j.desal.2019.02.001. [3] t. tong and m. elimelech, “the global rise of zero liquid discharge for wastewater management: drivers, technologies, and future directions,” environ. sci. technol., vol. 50, no. 13, pp. 6846–6855, 2016, doi: 10.1021/acs.est.6b01000. [4] a. f. al-alawy, t. r. abbas, and h. k. mohammed, “osmostic membrane bioreactor for oily wastewater treatment using external & internal configurations,” iraqi j. chem. pet. eng., vol. 17, no. 4, pp. 71–82, 2016. [5] m. s. al-rubaie, m. a. dixon, and t. r. abbas, “use of flocculated magnetic separation technology to treat iraqi oilfield co-produced water for injection purpose,” desalin. water treat., vol. 53, no. 8, pp. 2086–2091, 2015, doi: 10.1080/19443994.2013.860400. [6] b. i. h. waisi, u. f. a. karim, d. c. m. augustijn, m. h. o. al-furaiji, and s. j. m. h. hulscher, “a study on the quantities and potential use of produced water in southern iraq,” water sci. technol. water supply, vol. 15, no. 2, pp. 370–376, 2015, doi: 10.2166/ws.2014.122. [7] j. zhai et al., “comparison of coagulation pretreatment of produced water from natural gas well by polyaluminium chloride and polyferric sulphate coagulants,” environ. technol., vol. 38, no. 10, pp. 1200–1210, 2017, doi: 10.1080/09593330.2016.1217937. [8] a. a. al-haleem, h. h.abdulah, and e. a.-j. saeed, “components and treatments of oilfield produced water,” al-khawarizmi eng. j., vol. 6, no. 1, pp. 24–30, 2010. [9] a. a. a.-h. a.al-razaq, “oilfield produced water management: treatment, reuse and disposal,” baghdad sci. j., vol. 9, no. 1, pp. 124–132, 2012, doi: 10.21123/bsj.9.1.124-132. [10] f. i. el-hosiny, k. a. selim, m. a. a. khalek, and i. osama, “produced water treatment using a new designed electroflotation cell,” int. j. res. ind. eng., vol. 6, no. 4, pp. 328–338, 2017, doi: 10.22105/riej.2017.100959.1022. [11] a. fakhru’l-razi, a. pendashteh, z. z. abidin, l. c. abdullah, d. r. a. biak, and s. s. madaeni, “application of membrane-coupled sequencing batch reactor for oilfield produced water recycle and beneficial re-use,” bioresour. technol., vol. 101, no. 18, pp. 6942– 6949, 2010, doi: 10.1016/j.biortech.2010.04.005. [12] a. davarpanah, “feasible analysis of reusing flowback produced water in the operational performances of oil reservoirs,” environ. sci. pollut. res., vol. 25, no. 35, pp. 35387–35395, 2018, doi: 10.1007/s11356-0183506-9. [13] y. oren et al., “pilot studies on high recovery bwro-edr for near zero liquid discharge approach,” desalination, vol. 261, no. 3, pp. 321–330, 2010, doi: 10.1016/j.desal.2010.06.010. [14] y. shi et al., “solar evaporator with controlled salt precipitation for zero liquid discharge desalination,” environ. sci. technol., vol. 52, pp. 11822–11830, 2018, doi: 10.1021/acs.est.8b03300. [15] j. grönwall and a. c. jonsson, “the impact of ‘zero’ coming into fashion: zero liquid discharge uptake and socio-technical transitions in tirupur,” water altern., vol. 10, no. 2, pp. 602–624, 2017. [16] g. u. semblante, j. z. lee, l. y. lee, s. l. ong, and h. y. ng, “brine pre-treatment technologies for zero liquid discharge systems,” desalination, vol. 441, pp. 96–111, 2018, doi: 10.1016/j.desal.2018.04.006. [17] c. finnerty, l. zhang, d. l. sedlak, k. l. nelson, and b. mi, “synthetic graphene oxide leaf for solar desalination with zero liquid discharge,” environ. sci. technol., vol. 51, no. 20, pp. 11701–11709, 2017, doi: 10.1021/acs.est.7b03040. [18] r. d. braatz, m. fujiwara, d. l. ma, t. togkalidou, and d. k. tafti, “simulation and new sensor technologies for industrial crystallization: a review,” int. j. mod. phys. b, vol. 16, no. 1–2, pp. 346–353, 2002, doi: 10.1142/s0217979202009858. [19] l. theodore and f. ricci, mass transfer operations for the practicing engineer. john wiley & sons, inc., 2010. [20] c. j. geankoplis, transport processes and unit operations, third edit., vol. 20, no. 1. prentice-hall international, inc., 1993. https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/213 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/213 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/213 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/213 https://www.sciencedirect.com/science/article/abs/pii/s0011916418320861 https://www.sciencedirect.com/science/article/abs/pii/s0011916418320861 https://www.sciencedirect.com/science/article/abs/pii/s0011916418320861 https://www.sciencedirect.com/science/article/abs/pii/s0011916418320861 https://www.sciencedirect.com/science/article/abs/pii/s0011916418320861 https://www.sciencedirect.com/science/article/abs/pii/s0011916418320861 https://pubs.acs.org/doi/abs/10.1021/acs.est.6b01000 https://pubs.acs.org/doi/abs/10.1021/acs.est.6b01000 https://pubs.acs.org/doi/abs/10.1021/acs.est.6b01000 https://pubs.acs.org/doi/abs/10.1021/acs.est.6b01000 https://pubs.acs.org/doi/abs/10.1021/acs.est.6b01000 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/234 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/234 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/234 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/234 https://www.tandfonline.com/doi/abs/10.1080/19443994.2013.860400 https://www.tandfonline.com/doi/abs/10.1080/19443994.2013.860400 https://www.tandfonline.com/doi/abs/10.1080/19443994.2013.860400 https://www.tandfonline.com/doi/abs/10.1080/19443994.2013.860400 https://www.tandfonline.com/doi/abs/10.1080/19443994.2013.860400 https://iwaponline.com/ws/article-abstract/15/2/370/27466/a-study-on-the-quantities-and-potential-use-of https://iwaponline.com/ws/article-abstract/15/2/370/27466/a-study-on-the-quantities-and-potential-use-of https://iwaponline.com/ws/article-abstract/15/2/370/27466/a-study-on-the-quantities-and-potential-use-of https://iwaponline.com/ws/article-abstract/15/2/370/27466/a-study-on-the-quantities-and-potential-use-of https://iwaponline.com/ws/article-abstract/15/2/370/27466/a-study-on-the-quantities-and-potential-use-of https://www.tandfonline.com/doi/abs/10.1080/09593330.2016.1217937 https://www.tandfonline.com/doi/abs/10.1080/09593330.2016.1217937 https://www.tandfonline.com/doi/abs/10.1080/09593330.2016.1217937 https://www.tandfonline.com/doi/abs/10.1080/09593330.2016.1217937 https://www.tandfonline.com/doi/abs/10.1080/09593330.2016.1217937 https://alkej.uobaghdad.edu.iq/index.php/alkej/article/view/476 https://alkej.uobaghdad.edu.iq/index.php/alkej/article/view/476 https://alkej.uobaghdad.edu.iq/index.php/alkej/article/view/476 https://alkej.uobaghdad.edu.iq/index.php/alkej/article/view/476 https://www.iasj.net/iasj/article/24275 https://www.iasj.net/iasj/article/24275 https://www.iasj.net/iasj/article/24275 https://www.iasj.net/iasj/article/24275 https://www.sciencedirect.com/science/article/abs/pii/s0960852410006656 https://www.sciencedirect.com/science/article/abs/pii/s0960852410006656 https://www.sciencedirect.com/science/article/abs/pii/s0960852410006656 https://www.sciencedirect.com/science/article/abs/pii/s0960852410006656 https://www.sciencedirect.com/science/article/abs/pii/s0960852410006656 https://www.sciencedirect.com/science/article/abs/pii/s0960852410006656 https://link.springer.com/article/10.1007/s11356-018-3506-9 https://link.springer.com/article/10.1007/s11356-018-3506-9 https://link.springer.com/article/10.1007/s11356-018-3506-9 https://link.springer.com/article/10.1007/s11356-018-3506-9 https://link.springer.com/article/10.1007/s11356-018-3506-9 https://www.sciencedirect.com/science/article/abs/pii/s0011916410004029 https://www.sciencedirect.com/science/article/abs/pii/s0011916410004029 https://www.sciencedirect.com/science/article/abs/pii/s0011916410004029 https://www.sciencedirect.com/science/article/abs/pii/s0011916410004029 https://pubs.acs.org/doi/abs/10.1021/acs.est.8b03300 https://pubs.acs.org/doi/abs/10.1021/acs.est.8b03300 https://pubs.acs.org/doi/abs/10.1021/acs.est.8b03300 https://pubs.acs.org/doi/abs/10.1021/acs.est.8b03300 https://www.water-alternatives.org/index.php/alldoc/articles/vol10/v10issue2/372-a10-2-22/file https://www.water-alternatives.org/index.php/alldoc/articles/vol10/v10issue2/372-a10-2-22/file https://www.water-alternatives.org/index.php/alldoc/articles/vol10/v10issue2/372-a10-2-22/file https://www.water-alternatives.org/index.php/alldoc/articles/vol10/v10issue2/372-a10-2-22/file https://www.sciencedirect.com/science/article/abs/pii/s001191641830119x https://www.sciencedirect.com/science/article/abs/pii/s001191641830119x https://www.sciencedirect.com/science/article/abs/pii/s001191641830119x https://www.sciencedirect.com/science/article/abs/pii/s001191641830119x https://pubs.acs.org/doi/abs/10.1021/acs.est.7b03040 https://pubs.acs.org/doi/abs/10.1021/acs.est.7b03040 https://pubs.acs.org/doi/abs/10.1021/acs.est.7b03040 https://pubs.acs.org/doi/abs/10.1021/acs.est.7b03040 https://pubs.acs.org/doi/abs/10.1021/acs.est.7b03040 https://www.worldscientific.com/doi/abs/10.1142/s0217979202009858 https://www.worldscientific.com/doi/abs/10.1142/s0217979202009858 https://www.worldscientific.com/doi/abs/10.1142/s0217979202009858 https://www.worldscientific.com/doi/abs/10.1142/s0217979202009858 https://www.worldscientific.com/doi/abs/10.1142/s0217979202009858 https://books.google.iq/books?hl=en&lr=&id=5k2qtvs-f8kc&oi=fnd&pg=pt14&dq=%5b19%5d%09l.+theodore+and+f.+ricci,+mass+transfer+operations+for+the+practicing+engineer.+john+wiley+%26+sons,+inc.,+2010.&ots=gno0asqu6n&sig=lokgbw2l3cofnb5frvhrlgjjhlw&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=5k2qtvs-f8kc&oi=fnd&pg=pt14&dq=%5b19%5d%09l.+theodore+and+f.+ricci,+mass+transfer+operations+for+the+practicing+engineer.+john+wiley+%26+sons,+inc.,+2010.&ots=gno0asqu6n&sig=lokgbw2l3cofnb5frvhrlgjjhlw&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=5k2qtvs-f8kc&oi=fnd&pg=pt14&dq=%5b19%5d%09l.+theodore+and+f.+ricci,+mass+transfer+operations+for+the+practicing+engineer.+john+wiley+%26+sons,+inc.,+2010.&ots=gno0asqu6n&sig=lokgbw2l3cofnb5frvhrlgjjhlw&redir_esc=y#v=onepage&q&f=false m. h. salih and a. f. al-alawy / iraqi journal of chemical and petroleum engineering 23,1 (2022) 15 22 21 [21] b. s. choi, "crystallization of sodium chloride from a concentrated calcium chloride-potassium chloride-sodium chloride solution in a cmsmpr crystallizer: observation of crystal size distribution and model validation." phd diss., the university of utah, 2005. [22] w. l. mccabe, j. c. smith, and p. harriott, unit operation of chemical engineering, fifth edit. mcgrawhill, inc., 1993. [23] j. shanti and s. r. vijayalakshmi, “microcontroller based rotary evaporator for solution growth,” asian j. adv. basic sci., vol. 3, no. 1, pp. 89–93, 2014. [24] s. y. misyura, “different modes of heat transfer and crystallization in a drop of nacl solution: the influence of key factors on the crystallization rate and the heat transfer coefficient,” int. j. therm. sci., vol. 159, p. 106602, 2021, [online]. [25] a. panagopoulos, k. j. haralambous, and m. loizidou, “desalination brine disposal methods and treatment technologies a review,” sci. total environ., vol. 693, p. 133545, 2019, doi: 10.1016/j.scitotenv.2019.07.351. [26] e. t. igunnu and g. z. chen, “produced water treatment technologies,” int. j. low-carbon technol., vol. 9, pp. 157–177, 2014, doi: 10.2118/27177-ms. [27] m. h. salih, a. f. al-alawy, and t. a. ahmed, “oil skimming followed by coagulation/flocculation processes for oilfield produced water treatment and zero liquid discharge system application,” aip conf. proc., vol. 2372, pp. 1–11, 2021. [28] m. h. salih and a. f. al-alawy, “a novel forward osmosis for treatment of high-salinity east baghdad oilfield produced water as a part of a zero liquid discharge system,” desalin. water treat., vol. 248, pp. 18–27, 2022, doi: 10.5004/dwt.2022.28070. [29] x. chen, q. zheng, and y. dong, “theoretical estimation of evaporation heat in paper drying process based on drying curve,” processes, vol. 9, no. 7, pp. 1– 11, 2021, doi: 10.3390/pr9071117. [30] a. f. al-alawy, “forward and reverse osmosis process for recovery and re-use of water from polluted water by phenol,” j. eng., vol. 17, no. 4, pp. 912–928, 2011. [31] a. naillon, p. duru, m. marcoux, and m. prat, “evaporation with sodium chloride crystallization in a capillary tube,” j. cryst. growth, vol. 422, pp. 52–61, 2015, doi: 10.1016/j.jcrysgro.2015.04.010. https://www.proquest.com/openview/c0f87f5a5bcfb82ef72c02f07a45de62/1?pq-origsite=gscholar&cbl=18750&diss=y https://www.proquest.com/openview/c0f87f5a5bcfb82ef72c02f07a45de62/1?pq-origsite=gscholar&cbl=18750&diss=y https://www.proquest.com/openview/c0f87f5a5bcfb82ef72c02f07a45de62/1?pq-origsite=gscholar&cbl=18750&diss=y https://www.proquest.com/openview/c0f87f5a5bcfb82ef72c02f07a45de62/1?pq-origsite=gscholar&cbl=18750&diss=y https://www.proquest.com/openview/c0f87f5a5bcfb82ef72c02f07a45de62/1?pq-origsite=gscholar&cbl=18750&diss=y https://www.proquest.com/openview/c0f87f5a5bcfb82ef72c02f07a45de62/1?pq-origsite=gscholar&cbl=18750&diss=y https://www.researchgate.net/profile/vijayalakshmi-sr/publication/304216366_microcontroller_based_rotary_evaporator_for_solution_growth/links/5769d46308ae1a43d23a3a49/microcontroller-based-rotary-evaporator-for-solution-growth.pdf https://www.researchgate.net/profile/vijayalakshmi-sr/publication/304216366_microcontroller_based_rotary_evaporator_for_solution_growth/links/5769d46308ae1a43d23a3a49/microcontroller-based-rotary-evaporator-for-solution-growth.pdf https://www.researchgate.net/profile/vijayalakshmi-sr/publication/304216366_microcontroller_based_rotary_evaporator_for_solution_growth/links/5769d46308ae1a43d23a3a49/microcontroller-based-rotary-evaporator-for-solution-growth.pdf https://www.sciencedirect.com/science/article/abs/pii/s1290072920310528 https://www.sciencedirect.com/science/article/abs/pii/s1290072920310528 https://www.sciencedirect.com/science/article/abs/pii/s1290072920310528 https://www.sciencedirect.com/science/article/abs/pii/s1290072920310528 https://www.sciencedirect.com/science/article/abs/pii/s1290072920310528 https://www.sciencedirect.com/science/article/abs/pii/s0048969719334655 https://www.sciencedirect.com/science/article/abs/pii/s0048969719334655 https://www.sciencedirect.com/science/article/abs/pii/s0048969719334655 https://www.sciencedirect.com/science/article/abs/pii/s0048969719334655 https://www.sciencedirect.com/science/article/abs/pii/s0048969719334655 https://academic.oup.com/ijlct/article/9/3/157/807670?login=true https://academic.oup.com/ijlct/article/9/3/157/807670?login=true https://academic.oup.com/ijlct/article/9/3/157/807670?login=true https://aip.scitation.org/doi/abs/10.1063/5.0065365 https://aip.scitation.org/doi/abs/10.1063/5.0065365 https://aip.scitation.org/doi/abs/10.1063/5.0065365 https://aip.scitation.org/doi/abs/10.1063/5.0065365 https://aip.scitation.org/doi/abs/10.1063/5.0065365 https://www.deswater.com/dwt_abstracts/vol_248/248_2022_18.pdf https://www.deswater.com/dwt_abstracts/vol_248/248_2022_18.pdf https://www.deswater.com/dwt_abstracts/vol_248/248_2022_18.pdf https://www.deswater.com/dwt_abstracts/vol_248/248_2022_18.pdf https://www.deswater.com/dwt_abstracts/vol_248/248_2022_18.pdf https://www.mdpi.com/2227-9717/9/7/1117 https://www.mdpi.com/2227-9717/9/7/1117 https://www.mdpi.com/2227-9717/9/7/1117 https://www.mdpi.com/2227-9717/9/7/1117 https://www.iasj.net/iasj/download/9b878d64b7bfad62 https://www.iasj.net/iasj/download/9b878d64b7bfad62 https://www.iasj.net/iasj/download/9b878d64b7bfad62 https://www.iasj.net/iasj/download/9b878d64b7bfad62 https://www.sciencedirect.com/science/article/pii/s0022024815002936 https://www.sciencedirect.com/science/article/pii/s0022024815002936 https://www.sciencedirect.com/science/article/pii/s0022024815002936 https://www.sciencedirect.com/science/article/pii/s0022024815002936 m. h. salih and a. f. al-alawy / iraqi journal of chemical and petroleum engineering 23,1 (2022) 15 22 22 نظام التصريف السائل الصفري لمعالجة المياه المصاحبة عملية البلورة كجزء نهائي من لحقل شرق بغداد النفطي ميقات حسن صالح و أحمد فائق العلوي قسم الهندسة الكيمياوية, كلية الهندسة, جامعة بغداد, بغداد, العراق. الخالصة هذه الدراسة تطبيق عملية التبلور للمياه المصاحبة لحقول النفط من حقل شرق بغداد النفطي التابع م فيت من عدة أجزاء مثل قشط الزيت (zld) لشركة نفط الوسط )العراق(. يتكون نظام التصريف السائل الصفري يًرا من نظام التصريف السائل والتخثر / التلبد والتناضح األمامي والتبلور ، وتعد عملية التبلور جزًءا أخ الصفري. تم استخدام نظام التبخر البسيط على نطاق المختبر لتقييم أداء عملية التبلور. في هذا العمل تم استخدام محلول كلوريد الصوديوم والمياه المصاحبة لحقول النفط من حقل شرق بغداد كمحلول داخل بتركيز و 300درجة مئوية( وسرعة الخلط ) 90و 80و 70رجة الحرارة )غم/ لتر. تم دراسة تأثير د 220و 177 ساعة( على أداء 9.5-0.5غم / لتر( والوقت ) 220و 177دورة في الدقيقة( وتركيز الداخل ) 500و 400 التبلور بالنسبة لمعالجة المياه المصاحبة لحقول النفط، تم فحص معدل التبخر واالسترداد. يزداد االسترداد مع . تم استعادة المياه النقية واألمالح من داخلدة درجة الحرارة وسرعة الخلط بينما يتناقص مع زيادة تركيز الزيا غم 220دورة في الدقيقة و 400درجة مئوية و 80الماء المصاحب المركز. كان استخالص الماء النقي عند الصوديوم )أي المياه الممصاحبة ساعة لمحلول كلوريد 5.5٪ بعد 81.35و 82.22/ لتر تركيز الداخل .لحقل النفط المحاكاة( والمياه المصاحبة لحقل النفط ، على التوالي الكلمات الدالة: التبلور, التبخير, نظام التصريف السائل الصفري, المياه المصاحبة لحقول النفط العراقية. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol. 24 no.2 (june 2023) 19 – 30 eissn: 2618-0707, pissn: 1997-4884 *corresponding author: name: mohammed mahdi, email: mohammed.suhaib1607m@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. influence of nanofluid flooding on oil displacement in porous media mohammed mahdi a, *, sarmad al-anssari a, b, and zain-ul-abedin arain c a chemical engineering department, college of engineering, university of baghdad, baghdad, iraq b school of engineering, edith cowan university, 270 joondalup drive, joondalup, wa, 6027, australia c department of petroleum engineering, wa school of mines: minerals, energy and chemical engineering, curtin university, 26 dick perry avenue, 6151, kensington, australia abstract hydrocarbon displacement at the pore scale is mainly controlled by the wetness properties of the porous media. consequently, several techniques including nanofluid flooding were implemented to manipulate the wetting behavior of the pore space in oil reservoirs. this study thus focuses on monitoring the displacement of oil from artificial glass porous media, as a representative for sandstone reservoirs, before and after nanofluid flooding. experiments were conducted at various temperatures (25 – 50° c), nanoparticles concentrations (0.001 – 0.05 wt% sio2 nps), salinity (0.1 – 2 wt% nacl), and flooding time. images were taken via a high-resolution microscopic camera and analyzed to investigate the displacement of the oil at different conditions. in addition, contact angle measurements on quartz surfaces were also conducted at similar conditions to understand the flow behavior in the porous media. further, zeta potential and particle size distribution measurements were conducted to examine the stability of the injected nanofluids. results revealed that the injection of nanofluids into oil-wet pore space can significantly enhance the recovery rate of hydrocarbon by altering the wettability of the porous media. however, salinity, particularly at high nanoparticles concentration (≥ 0.005) can dramatically reduce the efficiency of nanofluid. further, increased aging time can improve the ability of nanofluid to alter the wettability of the surface, and thus more oil can be displaced. thus, nanofluid can efficiently enhance oil recovery if correctly formulated. keywords: nanofluid, silica, nanoparticles, porous media, wettability, eor. received on 10/12/2022, received in revised form on 24/04/2023, accepted on 28/04/2023, published on 30/06/2023 https://doi.org/10.31699/ijcpe.2023.2.3 1introduction the continuous growth of energy demand along with the decline of oil production from mature oil reservoirs has drawn attention to applying new technologies including nanotechnology in enhanced oil recovery (eor, which is also called tertiary oil recovery) applications. dispersions of nanoparticles (nps) in a liquid phase are called nanofluids. such liquid phases can be surfactant micelles, polymer, di water, brine, or oil [1, 2]. many underground applications such as geothermal extraction [3, 4], soil purification [5], wellbore drilling [6], carbon capture and storage (ccs) [7, 8], and eor [9-11], which this study focused on, have shown great potentials for nanofluids. typically, primary oil recovery can produce no more than 15-20% of the original oil in place (ooip) [12]. eor techniques are costly procedures used to increase oil production from depleted oil reservoirs through various thermal and/or chemical methods. thus, when no more oil is produced, eor is implemented to resumption oil production via the modification of the interfacial properties of the formations [13]. to facilitate the displacement of oil by water from the porous media, chemically enhanced oil recovery (ceor) methods are utilized to shift the wettability of the subsurface formations towards a more water-wet status and reduce the interfacial tension [14, 15]. the efficiency of oil production from depleted oil reservoirs mainly depends on the wettability of surfaces in the pore space [16]. in this situation, extremely oil-saturated rocks have a strongly oil-wet state under reservoir conditions. the most challenging process in oil recovery is to change the wettability of such oil-saturated porous media to waterwet [17]. strongly oil-wet formations may become waterwet with the flooding of surface-active chemicals including surfactants and polymers into oil reservoirs. however, in addition to the high-cost issues, there are environmental challenges associated with injecting such chemicals into the subsurface formations [18]. dispersion of nps in a liquid phase is an elegant alternative for that costly and harmful chemical [19]. recently, inorganic fillers, particularly silica (silicon dioxide; sio2) nps, showed a wide range of potential in science and industries, including food, cosmetics, medicine delivery, and geological applications like aquifer cleansing, ccs, and eor [20]. silica nps are environment-friendly materials with no harmful effects on the ecosystem. in http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:mohammed.suhaib1607m@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2023.2.3 m. mahdi et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 19 30 20 most cases, silica nps can increase hydrocarbon recovery by turning oil-wet surfaces into wet surfaces [21]. in the last decade, many studies have been conducted to understand the role of nps in eor. most of these studies have concentrated on the effect of nps on interfacial properties including wettability and interfacial tension (ift). in this context, nps with their unique small size can detach oil components from the oil-wet surfaces via structural disjoining pressure (sdp) of nps at the edge point of the solid-oil-water system [17, 20, 22]. wettability and wettability alteration are typically investigated via contact angle measurements [23]. studies showed that compare to several nps types, silica nps can drastically decrease the contact water-contact angle referring to a significant shift of wettability in water-wet conditions [24] at ambient conditions. other studies revealed that silica nps are efficient wettability modifier agents even in reservoirs’ harsh conditions including high pressure and temperature [25]. later studies have investigated the potential of surface-modified silica nps on oil recovery [26]. recently, researchers have investigated the synergistic effects of nps and other surface materials including surfactants and/or polymers on the wettability of oil-wet surfaces [2]. on the other hand, a limited number of studies have investigated the effect of nps on oil recovery via the amount of recovered oil using a core-flooding setup [27]. in such studies, the efficiency of nps is examined according to the access amount of recovered oil. in this study, a glass porous media was used to monitor the fluid distribution and flow behavior in pore space and investigate the influence of silica nanofluid as a wettability modifier on the displacement of oil from oilwet pore space. to the best of our knowledge, this work gives the first insight into the effect of nps on oil displacement in a porous media via monitoring the altering of wettability and displacing of oil along the treatment time. 2experimental 2.1. materials silicon dioxide (sio2 purity 99.5%) nps from sigma aldrich were dispersed in di water (from david grey, conductivity 0.02 ms/cm) or brine to formulate various nanofluids. nacl (purity 99.5 mol%, from rowe scientific) was used to formulate various concentrations of brine. crude oil (from amarah oil field, density 0.893 g/ml, api gravity 26.8, salt content 28 ppm, water content 0.065 %wt.) was used to fill the porous media. the model porous media was made out of a glass with a specific pattern and dimensions (30x30x1 mm, fig. 1) where the pore throat size of the glass model is (1 mm), which can be utilized to systematically carry out many tests to study the displacement of oil by a nanofluid. the glass porous model served as a representative for a sandstone reservoir. according to an xrd analysis of a rock core taken from a sandstone oil reserve [28], the sandstone formation is typically composed primarily of quartz (84 wt% quartz). therefore, all initial assessments of surface wettability in this investigation were made on smooth quartz crystal surfaces before and after treatments with crude oil and/or nanofluids. the sample employed in this study was extremely smooth, according to afm measurements. around 55 nm was the root mean square (rms) roughness [29]. fig. 1. glass porous media a magnetic stirrer (table 1) and ultrasonic homogenizer (300 vt ultrasonic homogenizer/biologics) were used to formulate different fluids. further, a digital plastic syringe pump with injection speeds ranging from 0.1 to 99.9 ml/h was used to feed different fluids (di water, brine, crude oil, nanofluid, and cleaning agents) into the porous media. table 1. specifications of magnetic stirrer item description model 1.613.01.001, digital stirrer/ hotplate, metal plate, 630 w heated area, mm diameter =130 temp plate. °c 0-280 stirrer speed, rpm 0-1500 rpm overall dimensions (w x d x h), mm 140 x 240 x50 electrical supply 200-240v, 50/60hz 2.2. formulation of nanofluid nanofluids with various silica nps concentrations (0.01 to 0.05 wt% sio2) were studied to determine their stability, flow behavior, and oil displacement efficiency. nanofluids were formulated via sonicating sio2 nps in the base fluid. in this study, all the prepared dispersions were sonicated using the same sonication time (5 min) and power (240 v) to ensure identical formulation conditions [30, 31]. the time and power of the sonication process mostly depend on a load of dispersed nps. to evaluate any substantial unstable behaviors of the nps during the injection period, the nanodispersions were visually inspected. m. mahdi et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 19 30 21 2.3. zeta potential, particle size distribution, and sem measurements the physicochemical properties of silica nps and their interactions with the solid substrate were investigated utilizing different approaches. a zeta sizer (zs, malvern instrument, uk) was used to measure the zeta potential of silica nps in the nanofluid at various salinity and acidity. zeta potential is a direct scale of the surface electric charge of the surface charge of solid particles in the liquid phase [32]. typically, the value of zeta potential determines the stability behavior of the particles in the suspension (table 2) [33, 34]. dynamic light scattering (dls, malvern instrument, uk) was used to measure the particle size and particle size distribution of nps in the dispersions [35-37]. in addition, the adsorption behavior of nps on the surfaces was probed via a scanning electron microscope (sem, zeiss neon). table 2. zeta potential and stability zeta potential range (mv) stability status (0) (±10) extremely unstable (±11) – (±24) unstable (±25) – (±35) critically stable (±36) – (± 59) stable ≤ (±60) thermodynamically stable 2.4. contact angle measurements contact angle measurement is an international standard method for assessing the wetness behavior of a specific surface in a solid/fluid/fluid system [38]. in this study, the tilted plate technique (at 14 ° inclination, fig. 2) was used for direct measurements of advancing (θa) and receding (θr) contact angles simultaneously [23, 39]. this contact angle measurement will give preliminary advice about the optimum conditions (i.e. nps concentration, temperature, and time of nano-treatment) that are used during flooding the porose media with nanofluid. fig. 2. advancing and receding contact angle measured via tilted plate technique typically, sandstone including quartz and glass substrates are strongly water-wet surfaces that are desired for oil recovery. however, in real conditions, rocks in oil reservoirs tend to have an oil-wet and strongly oil-wet state due to immersing in crude oil for years. such oil-wet status holds tightly to the oleic phase in the pore space which dramatically reduces the displacement of oil. altering the wettability of such oil-wet surfaces into water-wet is the key to feasible oil recovery. thus, to mimic the potential scenarios in sandstone oil reservoirs, pure quartz samples that are originally strongly water-wet will be immersed in crude oil to shift their wettability to an oil-wet status similar to the real condition in oil reservoirs [40, 41]. subsequently, such oil-wet quartz samples will be treated with nanofluid to render their wettability into water-wet conditions that are favorable in eor processes [42]. 2.5. flooding processes and oil recovery in the artificial porous media, several flooding procedures were conducted to simulate scenarios in subsurface formations and oil recovery procedures from the oil reservoir. first, di water was used to efficiently clean the porous media from any contaminants including dust and glass off-cuts. after that, the porous media was dried with pure nitrogen. it is well agreed that the subsurface formation is a high-salinity environment. thus, brine (0.1 wt% nacl) was pumped into the model with a very low rate of injection (0.5 ml/h) to provide a salty condition in the place. such a relatively low concentration of brine was used to avoid the extremely high salinity and the subsequent instability of the lately injected nanofluid [33]. typically, a surfactant is added to the nanofluid to improve the stability of the dispersion in a high-salinity environment. however, in this work, no surfactant was added to ensure the accurate investigation of nps role in oil recovery without the synergistic effects of other surfaceactive materials. consequently, all wettability changes will be related to the influence of nps and thus accomplish the study's goal of figuring out how nps act as a wettability modifier in the porous medium. all fluids including brine, crude oil, and nanofluids were injected into the porous media at the same rate of injection (0.5 ml/h) via the syringe pump. further, all these fluids were collected from the outlet of the porous media using small transparent collectors. 2.6. monitoring of fluids the distribution of fluids in the porous media was monitored using a microscopic video camera (basler sca 640-70 fm, pixel size = 7.4 lm; frame rate = 71 fps; fujinon cctv lens: hf35ha-1b; 1:1.6/35 mm). directly and attentively the fluid flow was watched on the monitor while it was flowing in the porous media. images were also taken from the movie files for fluid flow behavior and oil recovery investigation. the retrieved images have a spatial magnification of 0.04 mm per pixel and a very high resolution. the crude oil's dark color makes it possible to starkly observe the displacement processes and wettability changes. three gray shades representing solid, nanofluid, and oil showed in the extracted photos. the color code in image-j was subsequently changed to convert the images to color. m. mahdi et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 19 30 22 3result and discussion 3.1. zeta potential measurements the surface charge of the nps in the liquid phase is indicated by the zeta potential [34]. the sign and value of zeta potential are typically determined by the type of nps, salinity, and acidity of the base fluid. as a result, nanofluids containing 0.01 wt% of silica nps were formulated at various salinity (0 to 2 wt.% nacl) and acidity (ph range from 2 to 9) to measure the zeta potentials of the suspensions using the zeta sizer, fig. 3. fig. 3. zeta potential of silica nps (0.01 wt%) in diwater at various ph the results demonstrate the negatively charged nature of silica nps, and they also demonstrate that the absolute value of the potential rose with ph until it reached a plateau (31 mv) at about ph = 6.25. although these findings are slightly different from earlier studies, it has nevertheless shown that such nanofluids are only marginally stable [36, 37]. zeta potential in this situation must be large enough to provide adequate repulsive forces between nps in the liquid phase. these repelling forces are necessary to keep each np separately floating in the liquid phase by preventing any adjusted nps from colliding and coalescing [43, 44]. the dispersion is categorized as unstable when the zeta potential value is lower or equal to 25 mv. above 35 mv, the suspension will be stable, while it will be critically stable between (25 35) mv [33]. typically, salinity of oil reservoir typically exhibits significant variance within the same formation [16]. thus, using various nacl concentrations, the impact of salinity on the zeta potential was studied. fig. 4 shows that, with a salt concentration of 2 wt% nacl in the liquid phase, zeta potential reaches very low values, around 0 mv. at such a status, the isoelectric point (iep) is reached leading to accelerated attraction process between adjusted particles due to losses of repulsive forces that present between similarly charged particles. this phenomenon is connected to how nacl ions balance the surface charge of nps [35]. consequently, the collision and coalescence processes between particles would accelerated and the size of the liquid phase particles will significantly rise [33]. therefore, it is crucial to gauge the size of the np particles in the salt-containing mixture. fig. 4. the effect of salt concentration on zeta potential of nanofluid (0.01 wt%) silica nps at different ph 3.2. particle size and particle size distribution the nano-size of the nps in the suspension has a major role on the function of nanofluids in surface treatment applications. therefore, it is important to maintain the nps' diameters in the base fluid within the nanoscale range (100 nm). this section of the study focused on nps load, fluid salinity, and nps size growth with time. fig. 5 depicts the particle size distribution of the nps in the fluid measured after 5 minutes from the sonication process. it’s clear that most nps at this time at size ranged between (35 – 55) nm which indicates a limited aggregation process. such aggregation phenomenon is mainly related to the high surface energy of nps and the screening impact of base fluid ions on the surface charge of nps [32]. fig. 5. particle size distribution of silica nps (0.01 wt% sio2) dispersed in di-water measured 5 minutes after formulation the effect of time on the particle size distribution of nps is depicted in fig. 6. it is obvious that the average size of nps grows with time to eventually reaches 150 nm after 90 minutes. such size growth is principally caused by the high surface energy of nps and the brownian motion that causes the adjusted nps to collide [33, 35, 36]. some particle collisions resulted in coalescence, which produced larger particles. such coalescence is highly predominant when the particle's zeta potential is low (≤ ±30 mv), and it can rapidly increase with time in the presence of an electrolyte [35, 37]. particle size and m. mahdi et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 19 30 23 particle size distribution measurement using the dynamic light scattering (dls) technique was used to examine such growing behavior of the particle size. note that the dls technique is a laser-based technique that only works accurately with transparent media [2, 45]. thus, all systematically tested nanofluid samples were diluted samples (low nps concentration) to avoid the opaque status of the sample. fig. 6. particle size distribution of silica nps (0.01 wt% sio2) dispersed in di-water measured 90 minutes after formulation salt has a considerable impact on particle size in the liquid phase, as shown in fig. 7. despite using a very low concentration of salt (0.1 wt% nacl), the particle size distribution was drastically shifted to bigger values, indicating an accelerated rate of particle aggregation. as previously mentioned, the main reason for such an increase in nps size is the impact of electrolyte ions on the surface charge of the particles [37, 45]. such screening effect of salt on the surface charges will consequently eliminate the repelling forces between solid particles [32, 33]. although it is anticipated that the salinity may reach very high concentrations (> 20 wt% nacl) at reservoir conditions [26], this study only used a small amount of salt due to device limitations. further, fluid injection into underground formations and the subsequent mobility of such fluids in the subsurface formations is a very low and time-consuming process. thus, the stability and size-growing behaviors of nps are necessary to be investigated over longer periods. fig. 7. particle size distribution of silica nps (0.01 wt% sio2) dispersed in di-water and 0.1 wt% nacl brine measured 90 minutes after formulation fig. 8 shows how particle size changed over the first day of the formulation. according to the findings, the presence of salt ions will cause the particle size to rise above 100 nm within the first hour of the formulation. fig. 8. the effect of time and base-fluid salinity on particle size typically, due to the relatively low zeta potential (-31 mv) which places the dispersion in the critically sable zone (25 -35 mv), nps dispersed in di-water can expand in size greater than 100 nm after 30 minutes even without the presence of salt ions. it’s thus necessary to add some chemicals which can supercharge the surfaces of particles and consequently stabilize nps in the liquid phase [17]. these chemicals are mainly surfactants [46], polymers [2], and surfactant-polymer combinations [47]. such a combination of surface active materials and nps can synergistically produce very stable colloid dispersions for eor applications [2, 33]. this study, however, focuses on nps' roles in the eor process. thus, all measurements will be made at zero or very low salinity (0.1 wt% nacl) and directly after the formulation of the nanofluid to prevent the need to add further additives. that’s how the sole effect of nps on the eor is investigated. 3.3. scanning electron microscope (sem) measurements using a scanning electron microscope (sem, zeiss neon 40esb fibsem), the surface characteristics and modifications were examined. the sem image in fig. 9 demonstrates that the surface of pure quartz is smooth and flat and thus suitable for contact angle measurements which quantify the wettability of the surface and different treatment stages [23, 28, 29]. this picture was taken after being cleaned with acetone and di water and then dried with nitrogen. even after cleaning, certain pollutants are still visible on the surface. such imperfections might be caused by contamination from the researcher's hand or by quartz fragments that were left on the surface. such impurities can dramatically impact the accurate measurements of contact angle [38]. as previously mentioned, submerging solid samples in crude oil will produce surfaces that are oil-wet or strongly oil-wet [41]. fig. 10, on the other hand, gives an image of the oil-wet substrate after nano-treatment for 30 minutes. the term nano-treatment refers to the immersing process of the oilwet quartz sample vertically in the nanofluid. it’s obvious m. mahdi et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 19 30 24 that significant nps clusters are distributed over the surface non-uniformly. such relatively large silica clusters indicate the instability of nanofluid even when formulated with di water [26]. fig. 9. sem image of pure quartz surface fig. 10. sem image of nano-treated oil-wet quartz surface with 0.01 wt.% sio2 nps in di water for 30 minutes even though the surfaces are similarly charged, the placement of silica nps on quartz surfaces can drastically modify the wetness characteristics of oil-wet surfaces into water-wet surfaces [11, 41]. only contact angle measurements can accurately quantify such a change in wettability. 3.4. effect of nps concentration on the contact angle the effect of nps load in the nanofluid (wt% of nps in the base fluid) was systematically investigated (fig. 11). in this section, a wide range of nps concentrations, ranging from (0.001 wt%) to (0.05 wt%), at two temperatures (25 and 50° c) were examined. further, the immersing time of quartz samples (the nano-treatment) was 60 minutes for all experiments. fig. 11. the effect of nps concentration (wt% silica nps in di water) at two different temperatures (25, and 50°c) for one hour of treatment this figure shows that the contact angle of the oil-wet surfaces decreases as nps concentration increases at both tested temperatures. typically, the number of nps per unit area in the nanofluid increase with nps concentration leading to larger numbers of nps that are available to be attached to the treated surface. this is consonant with previous studies conducted on different surfaces including limestone [12, 42, 48, 49] and sandstone [50]. it is apparent from the results that during the first hour of treatment, treating with dilute nanofluid (0.005 wt% nps) shows no obvious influence on contact angle reduction at both tested temperatures. however, increasing nps concentrations (0.02, and 0.018 wt%) results in a significant reduction of contact angle (≤ 75°, which refers to the alteration of wettability into water-wet). such reduction in contact angle refers to the gradual removal of oil components from the treated surface. mechanistically, the removal of oil component from the treated surface is mainly related to the structural disjoining pressure of nps of the edge of the oil-solid-liquid system [17, 20, 22]. another interesting observation in the figure is that a further increase in nanofluid concentration (≥ 0.04 wt% nps) has less influence on contact angle reduction. this is mainly due to reaching the adsorption capacity of the surface where the number of attached nps into the surface is the same as the number of detached ones. such phenomenon slightly depends on the temperature of treatment [25]. thus it is obvious that the efficiency of nps as a wettability modifier is slightly higher at higher temperatures (50°c). wherefore, all the next flooding tests in this study will be at low nps concentrations (≤0.1 wt% nps). such low concentrations are more reliable and feasible to be conducted in real oilfields. 3.5. crude oil flooding the wettability of the artificial porous media is strongly water-wet since it's made out of glass. consequently, to mimic the scenario in oil reservoirs, the wettability of the model should be switched to strongly oil-wet via aging with crude oil [42, 51, 52]. to achieve this, crude oil was injected into the artificial glass porous media and the inlet and outlet points of the model were sealed directly to avoid the penetration of air into the sample. after that, the m. mahdi et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 19 30 25 model's temperature was raised to 50°c for the desired time of aging (2 or 7 hours, fig. 12). after that, the two ends are opened, and the porous sample is carefully monitored to note changes in the distribution of oil via the microscopic camera. fig. 12. a specific spot of the artificial porous media after aging with crude oil for 2 (a) and 7 (b) hours at 50°c images show that the injected oil filled all the pore spaces. however, after 2 hours of aging, limited drops of oil were drained out of the sample resulting in a large air bubble in the sample (fig. 12 a). such phenomenon is related to the low capillary forces in the case of aging for 2 hours. in contrast, a very small air bubble was noticed at the same place of the sample after aging for 7 hours indicating stronger capillary force which tightly holds the oil phase in the pore space (fig. 12 b). further, no oil drop where drained out of the sample after 7 hours aging referring to strongly oil-wet status (contact angle ≥ 150°) [50]. thus, after aging with crude oil for 6 hours, the glass artificial porous media can typically stimulate the condition in oil reservoirs.  water flooding water flooding, also known as secondary oil recovery, is typically used when oil reservoirs stop producing oil spontaneously [13, 53]. in this section, the porous media, after aging with crude oil for 7 hours (fig. 13 a), was flooded with an excessive amount of water to extract as much oil as possible from the porous media (fig. 13 b). the water flooding process was conducted via a syringe pump at a very low rate of flow to mimic the scenario of water flooding in subsurface formations. in this context, water may typically displace oil from larger pore spaces and wide channels, leaving a considerable amount of oil trapped in the pore space (fig. 13 b). despite how much water is injected at this point; no further oil is recovered from the porous media. mechanistically, to produce more oil, the oil film must be separated from the oil-wet surface by significantly altering the wettability of the porous media [54]. such wettability alteration can be achieved via nanofluid flooding with an accurately formulated nanofluid. fig. 13. specific spot of the artificial porous media after aging with crude oil for 7 hours (a), and after water flooding (b) with an excess amount of water at 50°c  nanofluid flooding nanofluid flooding into glass artificial porous media will help to monitor the alteration of interfacial properties of the pore space via nano-priming (fig. 14). at the end of water flooding, a considerable amount of oil can be seen trapped in the pore space (fig. 14 a). results show that the use of nanofluid can significantly m. mahdi et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 19 30 26 increase oil recovery by displacing more oil from porous media (fig. 14 b). mechanistically, the adsorption of nps into the porous media can gradually detach oil droplets that move into the larger pores and bigger channels finding a way out of the porous media. as stated before, the structural disjoining pressure of nps controls the detachment of the oil phase from the pore space [22]. fig. 14. specific spot of the artificial porous media after flooding with an excess amount of water (a), and after nanofluid flooding (b) with 0.1 wt% silica nps for 3 hours at 50°c 4conclusion in this study, the fluid flow behavior of oil and water was explored before and after nanofluid flooding using a transparent glass porous media. before conducting flooding tests, the stability and particle size distribution of nps in the liquid phase were investigated. the results declared that the zeta potential dramatically decrease and particle size drastically increase with the presence of salt ions. contact angle measurement of pure, oil-wet, and nano-treated quartz surfaces was conducted to find the best nanofluid composition and operating condition for nanofluid flooding. the results showed that while immersing with crude oil can switch the wettability of pure quartz into oil-wet, treatment with nanofluids can efficiently render the wettability of oil-wet surfaces water-wet and strongly water-wet. and thus enhance oil recovery. flooding tests revealed that silica nps can efficiently improve water flooding and a significant amount of additional oil can be recovered by injection of nanofluid into the porous media. the nano-flooding scenario including the nano-treatment period, temperature, the salinity of the porous media, and most importantly nps concentrations in the nanofluid are the main factors that affect the recovery of additional oil from the pore spaces. acknowledgment the authors would like to thank associate professor alireza keshavarz of edith cowan university (ecu australia) for providing the artificial glass porous media. references [1] t. a. salih, s. h. sahi, and a. n. g. al-dujaili, "using different surfactants to increase oil recovery of rumaila field (experimental work)," iraqi journal of chemical and petroleum engineering, vol. 17, no. 3, pp. 11-31, 2016. [2] s. al-anssari et al., "synergistic effect of nanoparticles and polymers on the rheological properties of injection fluids: implications for enhanced oil recovery," energy & fuels, vol. 35, no. 7, pp. 6125-6135, 2021. https://doi.org/10.1016/j.ptlrs.2021.08.004 [3] z. ziabakhsh-ganji, h. m. nick, m. e. donselaar, and d. f. bruhn, "synergy potential for oil and geothermal energy exploitation," applied energy, vol. 212, pp. 1433-1447, 2018. https://doi.org/10.1016/j.apenergy.2017.12.113 [4] s. m. obyed, "study the effect of residence time parameters on thermal cracking extract phase lubricating oil," al-khwarizmi engineering journal, vol. 15, no. 3, pp. 51-59, 2019. [5] m. raad and b. abdulmajeed, "effect of modified hybrid nanoparticles on the properties of base oil," iraqi journal of chemical and petroleum engineering, vol. 23, no. 1, pp. 1-7, 2022. https://doi.org/10.31699/ijcpe.2022.1.1 [6] g. cheraghian, m. hemmati, m. masihi, and s. bazgir, "an experimental investigation of the enhanced oil recovery and improved performance of drilling fluids using titanium dioxide and fumed silica nanoparticles," journal of nanostructure in chemistry, vol. 3, pp. 1-9, 2013. https://doi.org/10.1186/2193-8865-3-78 [7] s. m. benson and f. m. orr, "carbon dioxide capture and storage," mrs bulletin, vol. 33, no. 4, pp. 303305, 2008. https://doi.org/10.1557/mrs2008.63 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/210 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/210 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/210 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/210 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/210 https://doi.org/10.1016/j.ptlrs.2021.08.004 https://doi.org/10.1016/j.apenergy.2017.12.113 https://alkej.uobaghdad.edu.iq/index.php/alkej/article/view/648 https://alkej.uobaghdad.edu.iq/index.php/alkej/article/view/648 https://alkej.uobaghdad.edu.iq/index.php/alkej/article/view/648 https://alkej.uobaghdad.edu.iq/index.php/alkej/article/view/648 https://doi.org/10.31699/ijcpe.2022.1.1 m. mahdi et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 19 30 27 [8] s. al-anssari, m. arif, s. wang, a. barifcani, m. lebedev, and s. iglauer, "co2 geo-storage capacity enhancement via nanofluid priming," international journal of greenhouse gas control, vol. 63, pp. 2025, 2017. https://doi.org/10.1016/j.ijggc.2017.04.015 [9] n. ogolo, o. olafuyi, and m. onyekonwu, "enhanced oil recovery using nanoparticles," in spe saudi arabia section technical symposium and exhibition, 2012: onepetro. https://doi.org/10.1016/j.ptlrs.2021.08.004 [10] s. al-anssari, z.-u.-a. arain, h. a. shanshool, a. keshavarz, and m. sarmadivaleh, "synergistic effect of hydrophilic nanoparticles and anionic surfactant on the stability and viscoelastic properties of oil in water (o/w) emulations; application for enhanced oil recovery (eor)," 2020. https://doi.org/10.52716/jprs.v10i4.366 [11] m. zargartalebi, r. kharrat, and n. barati, "enhancement of surfactant flooding performance by the use of silica nanoparticles," fuel, vol. 143, no. 0, pp. 21-27, 3/1/ 2015. https://doi.org/10.1016/j.fuel.2014.11.040 [12] s. al-anssari, a. barifcani, s. wang, m. lebedev, and s. iglauer, "wettability alteration of oil-wet carbonate by silica nanofluid," journal of colloid and interface science, vol. 461, pp. 435-442, 1/1/ 2016. https://doi.org/10.1016/j.jcis.2015.09.051 [13] y. li, "oil recovery by low salinity water injection into a reservoir: a new study of tertiary oil recovery mechanism," transport in porous media, journal article vol. 90, no. 2, pp. 333-362, 2011. https://doi.org/10.1007/s11242-011-9788-8 [14] g. rassoul and o. m. waheeb, "producing oil from dead oil wells using injected lpg," iraqi journal of chemical and petroleum engineering, vol. 11, no. 2, pp. 29-33, 2010. [15] m. s. kamal, a. s. sultan, and i. a. hussein, "screening of amphoteric and anionic surfactants for ceor applications using a novel approach," colloids and surfaces a: physicochemical and engineering aspects, vol. 476, pp. 17-23, 2015. https://doi.org/10.1016/j.colsurfa.2015.03.023 [16] c. h. arns et al., "pore scale characterization of carbonates using x-ray microtomography," spe journal, vol. 10, no. 4, pp. 475-484, 2005/12/1/ 2005. https://doi.org/10.2118/90368-pa [17] s. al-anssari et al., "wettability alteration of carbonate rocks via nanoparticle-anionic surfactant flooding at reservoirs conditions," presented at the spe symposium: production enhancement and cost optimisation, 7-8 november, kuala lumpur, malaysia, 2017/11/7/, 2017. https://doi.org/10.2118/189203-ms [18] m. t. al-shamkhani, "managing, controlling and improving the treatment of produced water using the six sigma methodology for the iraqi oil fields," 2013. [19] i. s. al-bayati, s. a. m. mohammed, and s. alanssari, "recovery of methyl orange from aqueous solutions by bulk liquid membrane process facilitated with anionic carrier," in aip conference proceedings, 2023, vol. 2414, no. 1, p. 060010: aip publishing llc. https://doi.org/10.1063/5.0114631 [20] s. f. j. al-anssari, "application of nanotechnology in chemical enhanced oil recovery and carbon storage," curtin university, 2018. [21] l. n. nwidee, "nanoparticles for enhanced oil recovery processes," curtin university, 2017. [22] h. zhang, t. s. ramakrishnan, a. nikolov, and d. wasan, "enhanced oil recovery driven by nanofilm structural disjoining pressure: flooding experiments and microvisualization," energy & fuels, vol. 30, no. 4, pp. 2771-2779, 2016/04/21 2016. https://doi.org/10.1021/acs.energyfuels.6b00035 [23] l. m. lander, l. m. siewierski, w. j. brittain, and e. a. vogler, "a systematic comparison of contact angle methods," langmuir, vol. 9, no. 8, pp. 22372239, 1993/08/01 1993. https://doi.org/10.1021/la00032a055 [24] n. moghaddam, rasoul, a. bahramian, z. fakhroueian, a. karimi, and s. arya, "comparative study of using nanoparticles for enhanced oil recovery: wettability alteration of carbonate rocks," energy & fuels, vol. 29, no. 4, pp. 21112119, 2015/04/16 2015. https://doi.org/10.1021/ef5024719 [25] s. al-anssari, m. arif, s. wang, a. barifcani, m. lebedev, and s. iglauer, "wettability of nanofluidmodified oil-wet calcite at reservoir conditions," fuel, vol. 211, pp. 405-414, 1/1/ 2018. https://doi.org/10.1016/j.fuel.2017.08.111 [26] z.-u. l. a. arain et al., "reversible and irreversible adsorption of bare and hybrid silica nanoparticles onto carbonate surface at reservoir condition," petroleum, vol. 6, no. 3, pp. 277-285, 2020/09/01/ 2020. https://doi.org/10.1016/j.petlm.2019.09.001 [27] l. hendraningrat, s. li, and o. torsæter, "a coreflood investigation of nanofluid enhanced oil recovery," journal of petroleum science and engineering, vol. 111, no. 0, pp. 128-138, 11/ 2013. https://doi.org/10.1016/j.petrol.2013.07.003 [28] s. hillier, "accurate quantitative analysis of clay and other minerals in sandstones by xrd: comparison of a rietveld and a reference intensity ratio (rir) method and the importance of sample preparation," clay minerals, vol. 35, no. 1, pp. 291-302, 2000. https://doi.org/10.1180/000985500546666 [29] p. k. gupta, d. inniss, c. r. kurkjian, and q. zhong, "nanoscale roughness of oxide glass surfaces," journal of non-crystalline solids, vol. 262, no. 1-3, pp. 200-206, 2000. https://doi.org/10.1016/s00223093(99)00662-6 https://doi.org/10.1016/j.ijggc.2017.04.015 https://doi.org/10.1016/j.ptlrs.2021.08.004 https://doi.org/10.52716/jprs.v10i4.366 https://doi.org/10.1016/j.fuel.2014.11.040 https://doi.org/10.1016/j.jcis.2015.09.051 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/374 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/374 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/374 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/374 https://doi.org/10.1016/j.colsurfa.2015.03.023 https://doi.org/10.2118/90368-pa https://doi.org/10.2118/189203-ms https://stars.library.ucf.edu/etd/2508/ https://stars.library.ucf.edu/etd/2508/ https://stars.library.ucf.edu/etd/2508/ https://stars.library.ucf.edu/etd/2508/ https://doi.org/10.1063/5.0114631 https://espace.curtin.edu.au/handle/20.500.11937/68331 https://espace.curtin.edu.au/handle/20.500.11937/68331 https://espace.curtin.edu.au/handle/20.500.11937/68331 https://espace.curtin.edu.au/handle/20.500.11937/59634 https://espace.curtin.edu.au/handle/20.500.11937/59634 https://doi.org/10.1021/acs.energyfuels.6b00035 https://doi.org/10.1021/la00032a055 https://doi.org/10.1021/ef5024719 https://doi.org/10.1016/j.fuel.2017.08.111 https://doi.org/10.1016/j.petlm.2019.09.001 https://doi.org/10.1016/j.petrol.2013.07.003 https://doi.org/10.1016/s0022-3093(99)00662-6 https://doi.org/10.1016/s0022-3093(99)00662-6 m. mahdi et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 19 30 28 [30] a. afzal, i. nawfal, i. mahbubul, and s. s. kumbar, "an overview on the effect of ultrasonication duration on different properties of nanofluids," journal of thermal analysis and calorimetry, vol. 135, no. 1, pp. 393-418, 2019. https://doi.org/10.1007/s10973-018-7144-8 [31] a. asadi et al., "effect of sonication characteristics on stability, thermophysical properties, and heat transfer of nanofluids: a comprehensive review," ultrasonics sonochemistry, vol. 58, p. 104701, 2019. https://doi.org/10.1016/j.ultsonch.2019.104701 [32] f. u. rahman awan et al., "stable dispersion of coal fines during hydraulic fracturing flowback in coal seam gas reservoirs an experimental study," arxiv e-prints, p. arxiv: 2011.06177, 2020. https://doi.org/10.1021/acs.energyfuels.0c00045 [33] s. al-anssari, m. arif, s. wang, a. barifcani, and s. iglauer, "stabilising nanofluids in saline environments," journal of colloid and interface science, vol. 508, pp. 222-229, 2017. https://doi.org/10.1016/j.jcis.2017.08.043 [34] y. t. he, j. wan, and t. tokunaga, "kinetic stability of hematite nanoparticles: the effect of particle sizes," journal of nanoparticle research, journal article vol. 10, no. 2, pp. 321-332, 2008. https://doi.org/10.1007/s11051-007-9255-1 [35] c. metin, l. lake, c. miranda, and q. nguyen, "stability of aqueous silica nanoparticle dispersions," (in english), journal of nanoparticle research, vol. 13, no. 2, pp. 839-850, 2011/02/01 2011. https://doi.org/10.1007/s11051-010-0085-1 [36] r. mondragon, j. e. julia, a. barba, and j. c. jarque, "characterization of silica–water nanofluids dispersed with an ultrasound probe: a study of their physical properties and stability," powder technology, vol. 224, pp. 138-146, 7// 2012. https://doi.org/10.1016/j.powtec.2012.02.043 [37] c. o. metin, r. t. bonnecaze, l. w. lake, c. r. miranda, and q. p. nguyen, "aggregation kinetics and shear rheology of aqueous silica suspensions," applied nanoscience, journal article vol. 4, no. 2, pp. 169-178, 2012. https://doi.org/10.1007/s13204-0120185-6 [38] s. iglauer, a. salamah, m. sarmadivaleh, k. liu, and c. phan, "contamination of silica surfaces: impact on water–co2–quartz and glass contact angle measurements," international journal of greenhouse gas control, vol. 22, no. 0, pp. 325-328, 3// 2014. https://doi.org/10.1016/j.ijggc.2014.01.006 [39] a. krishnan, y.-h. liu, p. cha, r. woodward, d. allara, and e. a. vogler, "an evaluation of methods for contact angle measurement," colloids and surfaces b: biointerfaces, vol. 43, no. 2, pp. 95-98, 2005. https://doi.org/10.1016/j.colsurfb.2005.04.003 [40] m. ali et al., "corrigendum to" organic acid concentration thresholds for ageing of carbonate minerals: implications for co 2 trapping/storage"[j. colloid interface sci. 534 (2019) 88-94]," journal of colloid and interface science, vol. 562, p. 615, 2020. https://doi.org/10.1016/j.jcis.2019.10.115 [41] m. ali et al., "assessment of wettability and rockfluid interfacial tension of caprock: implications for hydrogen and carbon dioxide geo-storage," international journal of hydrogen energy, vol. 47, no. 30, pp. 14104-14120, 2022. https://doi.org/10.1016/j.ijhydene.2022.02.149 [42] a. roustaei and h. bagherzadeh, "experimental investigation of sio2 nanoparticles on enhanced oil recovery of carbonate reservoirs,", journal of petroleum exploration and production technology, pp. 1-7, 2014/08/17 2014. https://doi.org/10.1007/s13202-014-0120-3 [43] r. mondragon, j. e. julia, a. barba, and j. c. jarque, "determination of the packing fraction of silica nanoparticles from the rheological and viscoelastic measurements of nanofluids," chemical engineering science, vol. 80, pp. 119-127, 2012. https://doi.org/10.1016/j.ces.2012.06.009 [44] k.-m. kim et al., "surface treatment of silica nanoparticles for stable and charge-controlled colloidal silica," international journal of nanomedicine, vol. 9, no. sup2, pp. 29-40, 2014. https://doi.org/10.2147/ijn.s57922 [45] a. soames, s. al-anssari, s. iglauer, a. barifcani, and r. gubner, "effect of wettability on particle settlement behavior within mono-ethylene glycol regeneration pre-treatment systems," journal of petroleum science and engineering, vol. 179, pp. 831-840, 2019. https://doi.org/10.1016/j.petrol.2019.04.108 [46] m. zargartalebi, n. barati, and r. kharrat, "influences of hydrophilic and hydrophobic silica nanoparticles on anionic surfactant properties: interfacial and adsorption behaviors," journal of petroleum science and engineering, vol. 119, no. 0, pp. 36-43, 7// 2014. https://doi.org/10.1016/j.petrol.2014.04.010 [47] t. sharma, g. suresh kumar, and j. s. sangwai, "enhanced oil recovery using oil-in-water (o/w) emulsion stabilized by nanoparticle, surfactant and polymer in the presence of nacl," geosystem engineering, vol. 17, no. 3, pp. 195-205, 2014/05/04 2014. https://doi.org/10.1080/12269328.2014.959622 [48] a. bayat, r. junin, r. mohsin, m. hokmabadi, and s. shamshirband, "influence of clay particles on al2o3 and tio2 nanoparticles transport and retention through limestone porous media: measurements and mechanisms," , journal of nanoparticle research, vol. 17, no. 5, pp. 1-14, 2015/05/15 2015, art. no. 219. https://doi.org/10.1007/s11051-015-3031-4 [49] p. rostami, m. sharifi, b. aminshahidy, and j. fahimpour, "enhanced oil recovery using silica nanoparticles in the presence of salts for wettability alteration," journal of dispersion science and technology, 2019. https://doi.org/10.1080/01932691.2019.1583575 https://doi.org/10.1016/j.ultsonch.2019.104701 https://doi.org/10.1021/acs.energyfuels.0c00045 https://doi.org/10.1016/j.jcis.2017.08.043 https://doi.org/10.1016/j.powtec.2012.02.043 https://doi.org/10.1016/j.ijggc.2014.01.006 https://doi.org/10.1016/j.colsurfb.2005.04.003 https://doi.org/10.1016/j.jcis.2019.10.115 https://doi.org/10.1016/j.ijhydene.2022.02.149 https://doi.org/10.1016/j.ces.2012.06.009 https://doi.org/10.2147/ijn.s57922 https://doi.org/10.1016/j.petrol.2019.04.108 https://doi.org/10.1016/j.petrol.2014.04.010 https://doi.org/10.1080/12269328.2014.959622 https://doi.org/10.1080/01932691.2019.1583575 m. mahdi et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 19 30 29 [50] b. m. huibers et al., "wettability alteration of sandstones by silica nanoparticle dispersions in light and heavy crude oil," journal of nanoparticle research, vol. 19, pp. 1-18, 2017. https://doi.org/10.1007/s11051-017-4011-7 [51] p. rostami, m. sharifi, b. aminshahidy, and j. fahimpour, "enhanced oil recovery using silica nanoparticles in the presence of salts for wettability alteration," journal of dispersion science and technology, pp. 1-12, 2019. https://doi.org/10.1080/01932691.2019.1583575 [52] j. s. buckley, y. liu, and s. monsterleet, "mechanisms of wetting alteration by crude oils," spe journal, vol. 3, no. 01, pp. 54-61, 1998/3/1/ 1998. https://doi.org/10.2118/37230-pa [53] s. kokal and a. al-kaabi, "enhanced oil recovery: challenges & opportunities," world petroleum council: official publication, vol. 64, pp. 64-69, 2010. [54] a. i. el-diasty and a. m. aly, "understanding the mechanism of nanoparticles applications in enhanced oil recovery," in spe north africa technical conference and exhibition, 2015: onepetro. https://doi.org/10.2118/175806-ms https://doi.org/10.1080/01932691.2019.1583575 https://doi.org/10.2118/37230-pa https://firstforum.org/wp-content/uploads/2021/05/publication_00466.pdf https://firstforum.org/wp-content/uploads/2021/05/publication_00466.pdf https://firstforum.org/wp-content/uploads/2021/05/publication_00466.pdf https://firstforum.org/wp-content/uploads/2021/05/publication_00466.pdf https://doi.org/10.2118/175806-ms m. mahdi et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 19 30 30 إزاحة النفط من الوسط المساميتأثير الغمر بمحلول النانو على 3 زين العابدين أريانو ،2، 1 سرمد فؤاد جابر االنصاري ،، *1 محمد مهدي الحيدري العراق ،بغداد ،جامعة بغداد ،كلية الهندسة ،قسم الهندسة الكيمياوية 1 استراليا ،جندلوب ،جامعة ادث كوان )اي سي يو( ،قسم هندسة النفط 2 استراليا ،بيرث ،جامعة كيرتن ،قسم هندسة النفط 3 الخالصة يتم التحكم في إزاحة الهيدروكربونات على نطاق المسام بشكل أساسي من خالل خصائص التبلل للوسط لوسط تبلل لالمسامي، وبالتالي تم تنفيذ العديد من التقنيات بما في ذلك غمر السوائل النانوية للتحكم بسلوك ال ع المصن ة إزاحة الزيت من الوسط المساميالمسامي في المكامن النفطية. وبالتالي تركز هذه الدراسة على مراقب رارة حمن الزجاج، كنموذج لمكامن الساندستون، مع وبدون الغمر بالمحلول النانوي. أجريت التجارب في درجات (، الملوحة nps 2sioبالوزن٪ 0.05 0.001درجة مئوية(، تراكيز الجسيمات النانوية ) 05-25مختلفة ) لمعالجة. تم التقاط الصور عبر كاميرا مجهرية عالية الدقة صوديوم(، وزمن ا٪ بالوزن كلوريد ال2 0.1) تماس وتحليل الصور للتحقق من إزاحة النفط في ظروف مختلفة. باإلضافة إلى ذلك، تم إجراء قياسات زاوية ال قياساتعلى أسطح الكوارتز أيًضا في ظروف مماثلة لفهم سلوك الوسط المسامي. باإلضافة الى ذلك، أجريت شحنة السطح وحجم الجسيمات لفحص ثبات واستقراريه السوائل النانوية المحقونة. كشفت النتائج أن حقن ى. ومعالسوائل النانوية في الوسط المسامي المتبلل بالزيت يمكن أن يعزز بشكل كبير إزاحة النفط بمعدل أعل ي عن ر يمكن ان تقلل من ثبات المحلول النانو ذلك، فإن زيادة تركيز الجسيمات النانوية والملوحة بشكل كبي سين طريق التكتل المتسارع للجسيمات النانوية. عالوة على ذلك، يمكن أن تؤدي زيادة وقت المعالجة إلى تح للمحلول ، يمكنقدرة الموائع النانوية في تغيير قابلية السطح للتبلل، وبالتالي يمكن إزاحة المزيد من النفط. لذلك عزيز استخالص النفط بكفاءة إذا تم تركيبه بشكل صحيح.النانوي ت المحاليل النانوية، السيليكا، الوسط المسامي، التبللية، تحسين انتاج النفط. :دالةالكلمات ال iraqi journal of chemical and petroleum engineering vol.14 no.1 (march 2013) 1524 issn: 1997-4884 reinforcement steel corrosion reduction by using fly ash from south baghdad power plant amel s. merzah, huda n. kalifa, taha h. abood and ishraq abdulkarim abstract corrosioninduced damage in reinforced concrete structure such as bridges, parking garages, and buildings, and the related cost for maintaining them in a serviceable condition, is a source of major concern for the owners of these structures. fly ash produced from south baghdad power plant with different concentrations (20, 25 and 30) % by weight from the cement ratio were used as a corrosion inhibitor as a weight ratio from the cement content. the concrete batch ratio under study was (1:1.5:3) cement, sand and gravel respectively which is used in iraq. all the raw materials used were locally manufactured. concrete slabs (250x250x70) mm dimensions were casted, using poly-wood molds. two steel bars were embedded in the central position of each slab at the midheight (about 35 mm), with a space of 100 mm between each other. a 16 concrete slabs were prepared (0, 20, 25 and 30) wt. % of fly ash. the specimens were partially immersed in 3.5 wt. % nacl solution in order to predict the corrosion. half-cell potential test technique was used to estimate the corrosion rate which is occurred in the steel bar due to the migration of chloride ions through the concrete, depending on the astm c876-08. the result shows that the potential values of steel in concrete were shifts to the positive direction with increasing the percentage of fly ash, because the reduction of porosity by the addition of fly ash which fill the pores and inhibit the chloride ions to reach to steel. the results also show that the further increase of fly ash (30%) the possibility of carbonation is increased which result in reduction its alkalinity, thereby permitting corrosion of embedded steel. introduction reinforced concrete is a versatile, economical and successful construction material. it can be molded to a variety of shapes and finishes. usually it is durable, performing well throughout its service life. however, sometimes it does not perform adequately as a result of poor design, poor construction, inadequate materials selection, a more severe environment than anticipated or a combination of these factors. the corrosion of reinforcing steel in concrete is a major problem facing civil engineers and surveyors today as they maintain an ageing infrastructure. potentially corrosion rehabilitation is a very large market for those who iraqi journal of chemical and petroleum engineering university of baghdad college of engineering reinforcement steel corrosion reduction by using fly ash from south baghdad power plant 16 ijcpe vol.14 no.1 (march 2013) -available online at: www.iasj.net develop the expertise to deal with the problem. it is also a major headache for those who are responsible for dealing with structures suffering from corrosion [1]. the deterioration of reinforcement concrete structure is major problem. the cost of repairing or replacing deterioration structures has become a major liability for highway, agencies. the primary cause of this deterioration (cracking, delamination, and spilling) is the corrosion of steel reinforcing bars due to chlorides. the two main sources of chlorides are deicing chemical and seawater. the most common chemical used has been sodium chloride. many bridges have also been built in coastal areas and are exposed to seawater. bridges built with black reinforcing steel are showing progressive concrete deterioration as the concentration of chloride ions increases. the average bridge deck located in a snow -belt state with black reinforcing steel and 40 mm (1.5 in) of concrete cover has shown spalling in about 7 to 10 years after construction and has required rehabilitation in about 20 years after construction. for most corrosion–protection measures, the basic principle is to prevent the chloride ions from reacting with the steel surface and also to increase the time needed for the chloride ions to penetrate through the concrete cover. while these measures generally do not stop corrosion from eventually initiating, they do increase the service life of reinforced concrete structures by slowing the corrosion process. cathode protection, however, has proven to be a successful corrosion –protection measure for conventionally reinforced and pretension, pre-stress concrete bridge members [2]. when corrosion occurs as shown in fig.(1), the steel reinforcement basically “dissolves” in the pore water, giving up electrons and forming cations (positively charged ions). the process of losing electrons is known as oxidation. the following chemical reaction represents the fundamental oxidation of steel reinforcement at the anode (the location that releases electrons). the anodic reaction: fe→fe +2 +2e ¯ …(1) where: fe is iron, fe +2 is ferrous-ion, and 2e ¯ are two free electrons. in the presence of water molecules and the free electrons, oxygen is transformed from a neutral molecule to an anion, which has become more negatively charged by gaining released electrons. this process is called reduction. the gain of electrons comes from a loss of electrons from two substances that react with each other. the following chemical equation illustrates the cathodic reaction (the reaction at the location that gains electrons) [3]. the cathodic reaction: o2+2h2o+2e¯→2oh¯ …(2) where: o2 is oxygen, h2o is water, and oh¯ is a hydroxyl ion. fig. 1, schematic of the corrosion process amel s. merzah, huda n. kalifa, taha h. abood and ishraq abdulkarim -available online at: www.iasj.net ijcpe vol.14 no.1 (march 2013) 17 the surface of the iron, at which oxidation occurs, serves as an anode. the two free electrons, 2e¯, created in the anodic reaction must be consumed elsewhere on the steel surface to preserve electrical neutrality in the system. in other words, it is not possible for a large amount of electrical charge to build up at one location. another chemical reaction must consume the electrons. oxidation and reduction are coupled together as electrons are transferred between them. this reaction consumes both water and oxygen. several more “downstream” reactions must occur for corrosion products to form. this process can be expressed through the following steps. first, as shown in eq.(3), the products of the anodic reaction, fe +2 , and the cathodic reaction, oh¯, react, producing ferrous hydroxide, fe(oh) 2 [3]. fe +2 +2oh¯→fe(oh)2 ...(3) in eq. (4), ferrous hydroxide, fe(oh)2, is further oxidized to form ferric hydroxide, fe (oh) 3. 4fe (oh) 2+o2+2h2o→4fe (oh)3 …(4) as a result of dehydration (from exposure to the environment), eq. (5) shows how ferric hydroxide becomes ferric oxide, fe2o3, commonly referred to as rust. 2fe(oh)3→fe2o3.h2o+2h2o …(5) the electrical current flow resulting from the above process and the generation and consumption of electrons in the anode and cathodereactions are used in macrocell and half-cell potential measurements to assess corrosion activity. interestingly, the fact that the anodic and cathodic reactions must balance each other for corrosion to proceed is the reason that epoxy coating are believed to protect steel reinforcement [3]. deterioration of concrete due to ingress of chloride ions is considered the major cause of premature corrosion of steel reinforcement, which may be internationally added most often as a constituent of accelerating admixtures. dissolved chloride ions also may penetrate unprotected hardened concrete in structures exposed to marine environments or to deicing salts. the reactions involved on the anodic and cathodic areas are: fe +2 +2cl¯→fecl2 … (6) fecl2+2h2o→fe(oh)2+2hcl …(7) fly ash blended cements are more suitable as binders for marine concrete structures than portland cements. the use of fly ash blended cement in marine concrete will lead to higher resistance to chloride attack and good resistance to seawater damage. the overall results are longer service life in marine exposure [8]. fly ash react with the cement hydration products, notably calcium hydroxide; hydraulic materials, such as granulated blast furnace slag, undergo direct hydration reactions for this reason it can improve the strength and durability of concrete [4]. thilgavathi et .al [2010] presents the laboratory investigations conducted to study the chloride permeability characteristics of admixed concrete specifically with fly ash (fa). rapid chloride permeability test (rcpt) was used to study the chloride permeability characteristics of concrete. the result suggests an optimized percentage of fa suitable for concrete in an aggressive environment and to develop correlation between various parameters, which are responsible for chloride permeability [5]. reinforcement steel corrosion reduction by using fly ash from south baghdad power plant 18 ijcpe vol.14 no.1 (march 2013) -available online at: www.iasj.net reddy d.v., et.al [2011] studied the durability characteristics of low calcium fly ash-based geopolymer concretes subjected to the marine environment, compared to ordinary portland cement concrete with similar exposure. to achieve this goal, 8 molar geopolymer, 14 molar geopolymer and ordinary portland cement concrete (opc) mixes were prepared and tested for exposure in seawater. the results show that the geopolymer concretes (gpc) excellent resistance to chlorideattack, with longer time to corrosion cracking, compared to ordinary portland cement concrete [6]. experimental work materials cement resisting portland cement produced by iraqi state company at al-gesser plant was used in this work. the chemical and physical properties of cement are listed in table (1) and (2) respectively. results confirmed to the iraqi standard specification (i.o.s) no. 5/1984[24].chemical and physical tests were carried out by specification institute for engineering industry (s.i.e.i) from table (1) to (6). table 1, chemical composition and main compounds of the cement used item chemical formula oxides content % limits of (i.o.s.) no.5/1984 iron oxide fe2o3 5 sulfate so3 2.5 < 2.5 silica sio2 26.2772 alumina al2o3 4.5 magnesia mgo 2.2084 < 5 insoluble ----0.3578 < 1.5 c3a ----3.475 < 3.5 cao ----rem rem table 2, physical properties of the cement used physical properties test results limits of (i.o.s.) no.5/1984 specific surface area m 2 /kg 330.2 ≥ 250 setting time initial setting, h: min final setting, h: min 1:45 4:05 ≥00:45 ≤10:00 compressive strength, n/mm 2 3days 7days 26.5 38.4 ≥ 15.0 ≥ 23.0 fine aggregate normal weight natural sand from alekhaider region was used as fine aggregate. table ( 3) and fig.(2) shows the sieve analysis of the fine aggregate used throughout this work. results show that the sand grading was within the requirements of the iraqi specification (i.o.s) no.45/1984. table (4) illustrates the chemical properties of the used sand. table 3, grading of fine aggregate sieve size (mm) % passing limits of (i.o.s.) no.45/1984 % retained 10 100 100 0 4.75 94.5 90-100 5.5 2.36 83.1 75-100 16.9 1.18 72.6 55-90 27.6 0.60 58.8 35-59 41.2 0.3 20.7 8-30 79.3 0.15 3.9 0-10 96.1 fineness modulus = ∑ % retained/100=2.666mm table 4, chemical properties of fine aggregate properties test results limit of specification sulfate content as so3 % 0.08 ≤1 (i.o.s.) no.45/1984 amel s. merzah, huda n. kalifa, taha h. abood and ishraq abdulkarim -available online at: www.iasj.net ijcpe vol.14 no.1 (march 2013) 19 fig. 2, grading curve for fine aggregate with (i.o.s.) limits coarse aggregate gravel of 37.5 mm maximum size was used as coarse aggregate. table (5) with fig. (3) shows the grading of coarse aggregate conforms to the iraqi specification no.45/1984. table (6) illustrates the chemical properties of the coarse aggregate in the present work. table 5, grading of coarse aggregate sieve size (mm) passing % passing % limits of (i.o.s.) no.45/1984 (5-40 mm) 75 100 100 37.5 100 95-100 20 68.6 35-70 10 11.9 10-40 5 1 0-5 table 6, chemical properties of coarse aggregate chemical properties test results limit of specification sulfate content % 0.088% ≤ 0.1% (i.o.s.) no.45/1984 fig. 3, grading curve for coarse aggregate with (i.o.s.) limits mixing water tap water was used for all batches. table (7) shows the chemical analysis of tap water. chemical and physical tests were carried out by ministry of science and technology /research center and laboratories water. table 7, chemical and physical analysis of tap water test value ppm so4 -2 81 cl -1 80 ca +2 128 mg +2 44 hco3 -2 122 co3 -2 0.0 na +1 50 k +1 2.5 phvalue 8 steel reinforcement deformed steel bars of diameter 10 mm were used as reinforcement in concrete. the steel bars were cleaned with degreasing agent followed with acetone. the end of each steel bar was coated with cement grout followed with epoxy paint to avoid unexpected crevice corrosion. fig. (4) shows the main reinforcement details. fig. 4, illustration of concrete specimens with two embedded steel bars corrosion inhibitors fly ash (fa) fly ash produced from south baghdad power plant was used as a corrosion inhibitor with a different 0 20 40 60 80 100 120 0 2 4 6 8 10 12 sieve size (mm) p e r c e n t a g e p a s s i n g % grading of fine aggregate specification specification 0 20 40 60 80 100 120 0 20 40 60 80 sieve size (mm) p e r c e n t a g e p a s s i n g % grading of aggregate specification specification reinforcement steel corrosion reduction by using fly ash from south baghdad power plant 20 ijcpe vol.14 no.1 (march 2013) -available online at: www.iasj.net concentration (20, 25 and 30) % by weight of cement. table (8) shows the chemical and physical analysis of fly ash. the tests were carried out at state company of geological survey and mining. concrete mixes locally resistance portland cement, sand and gravel were used to prepare concrete batch with mixing ratio 1:1.5:3 which are used in iraq. the three components with the above fixed ratios were mixed for (4 minutes); the standard consistency was done to estimate the true w/c ratio, which differs in the range (0.48 – 0.53), and slump ≈2. table 8, chemical analysis of fly ash item composition chemical composition % iron oxide fe2o3 6.7 sulfate so3 0.6 silica sio2 34.76 alumina al2o3 16.341 magnesia mgo 0.437 cao ----1.216 organic compounds co2 ≈ 42 mixing of concrete a mixer of about 0.1 m3 capacity was used to mix concrete ingredient. dry materials of reference concrete( without fly ash) were placed in mixers pan after it was cleaned from any remaining materials, and they were initially mixed before adding the required quantity of water to get uniform mixture. then the mixing water was added and the whole constituents were mixed for (4) minutes. the fly ash dried in electrical furnace at 40˚c for (24) hours and then sieved then the required quantity of fly ash was measured as a percentage from the binder (cement). preparations, casting and curing of the test specimens with dimension (250x250x70) mm the poly-wood molds were used for casting the specimens used in the corrosion test. two steel bars were embedded in parallel in the center portion of each slab at the mid-height (about 35 mm), with a space of 100 mm between each other, before casting the molds were cleaned and oiled by gas oil, the steel bars were cleaned with degreasing agent followed with acetone. the ends of each steel bar were coated with cement grout followed with epoxy paint to avoid unexpected crevice corrosion compaction was performed by means of vibrating table for about (2) minutes to remove any entrapped air; the concrete surfaces were leveled and smoothed by means of trowel and covered with nylon sheets to assure humid air for about (24) hours, the specimens were demolded and immersed in 3.5 wt % nacl of solution. measuring the density of hardened concrete using a buoyancy balance device the device as shown in fig. (5) consists of rigid support frame, incorporating a water tank mounted on a platform. a mechanical lifting device is used to raise the water tank through the frame height immersing the specimen suspended below the balance. the balance supplied may also be used as a standard weighing device. fig. 5, the illustration of buoyancy balance device amel s. merzah, huda n. kalifa, taha h. abood and ishraq abdulkarim -available online at: www.iasj.net ijcpe vol.14 no.1 (march 2013) 21 the weight of the specimen were measured, and the density computed using the following formulas. volume density=m/v (kg/m 3 ) …(8) where: m:the weight of specimen, v:the volume of specimen preparation of curing solution pure salt was used to prepare salt solution 3.5% nacl in tap water analyzed in table(7) two tanks are provided with pump to circulate the saltwater is used to immerse the slabs of concrete partially(3/4 of each specimen). twice daily, the water is circulated for one hour to ensure uniform chloride content within the tanks, and full aeration of the water. water depth and salt content were adjusted weekly. halfcell potential measurement it is an electrochemical technique commonly used by engineers to assess the severity of corrosion in reinforced concrete structure. the electrochemical potential of the reinforcing steel was measured against potassium chloride (kcl) electrode (sce), fig (6). the reference electrode accordance with the astm c876-91 standard, consists of the rigid tube or container shall have an inside diameter of not less than 1 in. (25 mm); the diameter of the porous plug shall not be less than 1⁄2 in. (13 mm); the diameter of the immersed copper rod shall not be less than 1⁄4 in. (6 mm), and the length shall not be less than (50) mm [7]. instrumentation the measuring setup fig (7) consists of: 1. reference electrode (re); a potassium chloride (kcl) electrode (sce) half –cell was used, consists of the rigid tube an inside diameter (10 mm); the diameter of the porous plug (4 mm); the diameter of the immersed rod (6 mm), and the length (110 mm). 2. digital voltmeter, aswar digital model dt830d was used for this purpose. the d.c voltage measurement was 2000 m v. test procedure 1. the reference electrode (re) was held vertically with the sponge folded around and attached to the tip of the half cell so that it provides electrical continuity between the porous plug and the concrete member. fig. (6). 2. electrically connect one end of the lead wire to the half cell and the other end of the same lead wire to the negative (ground) terminal of the voltmeter, the working electrode (steel reinforcement) was electrically connected to the positive terminal of d.c voltmeter fig. (6) 3. the half-cell potential can be read directly on the display of the voltmeter. 4. the results of half-cell potential measurements are interpreted as allows[27]: a. if potentials over an area are more positive than −0.20 v sce, there is a greater than 90 % probability that no reinforcing steel corrosion is occurring in that area at the time of measurement b. if potentials over an area are in the range of −0.20 to −0.35 v sce, corrosion activity of the reinforcing steel in that area is uncertain. c. if potentials over an area are more negative than −0.35 v sce, there is a greater than 90 % probability that reinforcing steel corrosion is occurring in that area at the time of measurement. reinforcement steel corrosion reduction by using fly ash from south baghdad power plant 22 ijcpe vol.14 no.1 (march 2013) -available online at: www.iasj.net fig. 6, the reference electrode results and discussion corrosion-induced deterioration of reinforced concrete structures occurs when the environmental loading on the structure is greater than ability of the structure to resist the environmental loading (environmental resistance). slump and standard consistency the slump and the standard consistancy of the prepared slubs, were tested, table (9) shows the result for concrete with and without fly ash. it is appeared that the w/c ratio and the slump increased due to addition of fly ash which contains mainly sio2 and al2o3 as shown in table (8). table 9, the slump and standard consistency w/(cement + fly ash) slump (mm) without fly ash 0.33 1 with 20% fly ash 0.37 2 with 25% fly ash 0.38 2 with 30% fly ash 0.38 2 density computation the density of the prepared slubs was measured using the formulas (8). table (10) shows the result which gives values with increasing fly ash; this is due to the reduction of the permability by adding the fly ash which lies in the pores formed through the concrete. table 10, the density computation of specimens specimens density ( kg/m 3 ) without fly ash 2340 20% fly ash 2372 25 % fly ash 2400 30% fly ash 2409 corrosion rate prediction figs. (7) to (10) illustrate the results of corrosion potential measurements of reinforcement steel reference to potassium chloride electrode, when partially immersed in salt solution for a period of about 60 days. results indicate that the half cell potential of steel was divided in two different ranges of values. the first (e >-250 mv) was observed during the first few days which is a characteristic of passive state. the second range (-250, -550 mv) was observed after 30 days and the passive film has been destroyed by the aggressive ions[7]. so the potential of steel after 60 days of immersion in nacl solution was (550,-500 and -175) mv for (20, 25 and 30) % fa concrete respectively, while the potential of steel in concrete specimen without fa was ( -400) mv. results show that the potentials value of steel in concrete were shifts to the positive direction(noble direction) with increasing the percentage of fly ash, but the values were oscillated due to the short periods of immersion in salt solution, were the periods may be reached to 480 days as in some researches. furthermore, the use of fly ash has a beneficial effect on corrosion resistance of steel in concrete due to the decreased permeability of chloride ions, through the concrete, which is clear from the values of the potential difference in figures. amel s. merzah, huda n. kalifa, taha h. abood and ishraq abdulkarim -available online at: www.iasj.net ijcpe vol.14 no.1 (march 2013) 23 the addition of fly ash increase the time required to initiate corrosion of reinforcement steel in concrete due to the inhibition of chloride ions to penetrate through the concrete, reaching to the steel bars. this is in good agreement with other literatures which present that the addition of fly ash reduce the corrosion rate[8]. the corrosion of steel in concrete happened due to the chlorides and carbonates ions[28], from the results shown in figures below it is cleared that the largest ratio of fly ash give more resistance to corrosion of steel in concrete ,this is may be due to the high ratio of carbon in fly ash as appeared in table (8) fig. 7, half-cell potentials of reinforcing bars in concrete with and without fly ash exposed in a 3.5% nacl solution fig. 8, half-cell potentials of reinforcing bars in concrete with 20% fly ash from the binder and without exposed in a 3.5% nacl solution fig. 9, half-cell potentials of reinforcing bars in concrete with 25% fly ash from the binder and without exposed in a 3.5% nacl solution fig. 10, half-cell potentials of reinforcing bars in concrete with 30% fly ash from the binder and without exposed in a 3.5% nacl solution conclusions 1. the addition of fly ash to the concrete batch increases the water cement ratio from 33% to 38% as shown in table (3.11). 2. the increasing in water ratio leads to increase the time required for solidification. 3. the density also increased. 4. the half-cell corrosion rate data shows detectable values for potential difference which give estimation for the migration of chloride ions within the concrete. 5. the potential value shifts to the positive direction (noble direction) with increasing of fly ash ratios. 6. the limited values for the potential difference ensure that the corrosion -650 -550 -450 -350 -250 -150 -50 exposure time (days) h a lf c e ll p o t e n t ia l ( m v , s c e ) 0% fly ash 20% fly ash 25% fly ash 30% fly ash 0% fly ash -100.46154 -210.2 -250.75 -300.75 -400.4 20% fly ash -120.53846 -226.2 -241.875 -290 -550.4 25% fly ash -140.92308 -231.2 -220.25 -350.75 -500.6 30% fly ash -150.30769 -170.6 -180.75 -200.7 -175.6 14 days 26 days 30 days 50 days 60 days -650 -550 -450 -350 -250 -150 -50 exposure time (days) h a lf c e ll p o t e n t ia l ( m v , s c e ) 0% fly ash 20% fly ash 0% fly ash -100.46154 -210.2 -250.75 -300.75 -400.4 20% fly ash -120.53846 -226.2 -241.875 -290 -550.4 14 days 26 days 30 days 50 days 60 days -650 -550 -450 -350 -250 -150 -50 exposure time (days) h a lf c e ll p o t e n t ia l ( m v , s c e ) 0% fly ash 25% fly ash 0% fly ash -100.46154 -210.2 -250.75 -300.75 -400.4 25% fly ash -140.92308 -231.2 -220.25 -350.75 -500.6 14 days 26 days 30 days 50 days 60 days -650 -550 -450 -350 -250 -150 -50 exposure time (days) h a lf c e ll p o t e n t ia l ( m v , s c e ) 0% fly ash 30% fly ash 0% fly ash -100.46154 -210.2 -250.75 -300.75 -400.4 30% fly ash -150.30769 -170.6 -180.75 -200.7 -175.6 14 days 26 days 30 days 50 days 60 days reinforcement steel corrosion reduction by using fly ash from south baghdad power plant 24 ijcpe vol.14 no.1 (march 2013) -available online at: www.iasj.net of the steel bars initiate after long time period (may be 3 months) but it can be increased steeply after that. 7. the corrosion of steel affected by the composition of fly ash, this is clear from the reduction of corrosion resistance by increasing the fly ash ratio because the effect of corrosion by carbonate. references 1) john p. broomfield " corrosion of steel in concrete : understanding, investigation and repair"(2003) 2) j.l.smith and y.p.virmani. "materials and methods for corrosion control of reinforcement and prestressed concrete structure in new construction" (publication no. 00-081). (2000). 3) brent m. phares, fouad s. fanous, terry j. wipf, yoon-si lee, milan j. jolley " evaluation of corrosion resistance of different steel reinforcement types" report no.ctre project 02-103. (2006) 4) pierre r. roberge." handbook of corrosion engineering".(1999) 5) thilgavathi s, dhinakaran g and venkataramana j "durability of fly ash concrete to chloride ingress" july, the iup journal of structural engineering, 2010. 6) d.v. reddy, j-b edouard, k. sobhan ,and a. tipnis " experimental evaluation of the durability of fly ash-based geopolymercncrete in the marine environmental" ninth laccei , engineering for a smart planet, innovation, information technology and computational tools for sustainable development, august 3-5, 2011, medellín, colombia. 7) astm c876-91(1999) standard test method for halfcell potentials of uncoated reinforcing steel in concrete. 8) fajarado. g., valdez.p., j. pacheco (2008)”corrosion of steel rebar embedded in natural pozzolan based mortars exposed to chlorides” construction and building materials pp.768774,(february). available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.23 no.4 (december 2022) 25 – 32 eissn: 2618-0707, pissn: 1997-4884 corresponding author: name: hasan ali abbood , email: hasan.abbood1607m@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. enhance the properties of lignosulfonate mud by adding nanoparticles of aluminum oxide and iron oxide hasan ali abbood and ibtehal kareem shakir chemical engineering department/college of engineering/university of baghdad/baghdad, iraq abstract oil well drilling fluid rheology, lubricity, swelling, and fluid loss control are all critical factors to take into account before beginning the hole's construction. drilling fluids can be made smoother, more cost-effective, and more efficient by investigating and evaluating the effects of various nanoparticles including aluminum oxide (al2o3) and iron oxide (fe2o3) on their performance. a drilling fluid's performance can be assessed by comparing its baseline characteristics to those of nanoparticle (nps) enhanced fluids. it was found that the drilling mud contained nps in concentrations of 0,0.25, 0. 5, 0.75 and 1 g. according to the results, when drilling fluid was used without nps, the coefficient of fraction (cof) was 44%, when added al2o3 np and fe2o3 np at 0.75g reduced cof by 31% and 33% respectively. when al2o3 and fe2o3 nps were used, particularly at a concentration of 1g, the amount of mud filtration decreased from 13.5ml to 9.3 ml and 8.5 ml respectively. additional improvements rheological properties as well as swelling when fe2o3nps and al2o3 nps were added at 1g. overall, it was found that adding nps to the lignosulfonate-wbm at a concentration of 1g can improve rheological, swelling, and filtration properties as well as lubrication at 0.75g. keywords: drilling mud; nanoparticles; lubrication; rheological; swelling. received on 20/05/2022, accepted on 19/07/2022, published on 30/12/2022 https://doi.org/10.31699/ijcpe.2022.4.4 1introduction extracting oil and gas from the ground begins with drilling. developing this operation to its full potential will help boost output. drilling mud is essential to achieving this goal. water, oil, synthetic, and pneumatic (air-based) drilling fluids are just a few of the many types of drilling fluids available. the most widely used fluid is water. about 80% of all wells are drilled with them because they are less expensive than oil or synthetic-based fluids [1]. to maximize oil recovery and shorten the time it takes to reach first oil, drilling fluids are an absolute necessity. drilling fluids can be likened to blood in the human body because they are used in the drilling process to remove rock. similarly, to how the kidneys and lungs remove waste from the body via the blood, the mud pump removes drilling cuttings from the bottom and transports them through drilling fluid to clean the mud before it is used again [2]. drilling muds are used to prevent reservoir fluids from entering the wellbore by providing hydrostatic pressure [3], reduce contact forces and torque between the drill string and wellbore [4], reduce the filtration rate [5], and transport drilling waste to the surface for cooling purposes [6]. when it comes to the construction and completion of a well, drilling mud is an essential consideration. any drilling operation's success is directly related to the quality and efficiency of its fluid mix, as well as its cost and environmental impact. pipe sticking and mud loss are two problems that can arise as a result of poor drilling fluid design. poor mud design can lead to other problems, such as bit balling and borehole collapse [7]. in recent years, nanotechnology has been used to improve the properties of nps. this is because nanomaterials' ability to improve fluid performance depends on their size and shape, which is determined by their ability to interact with mud components. some of the functions of drilling fluid, such as preventing drill cuttings and minimizing formation damage and stabilizing the wellbore. nanomaterials can be added to drilling fluids to perform any of these functions [8]. drilling fluid problems can be solved by utilizing nps with unusual characteristics, such as high thermal conductivity and a large surface area. a few of the most important advantages of using nanoparticles in drilling fluids are their reduced fluid loss and mud cake, as well as their ability to remove hazardous materials and enhance heat transfer, lubrication, and rheological properties such as viscosity [9]. the use of nano sized particles as an additive agent in drilling fluid formulations has been the subject of several experimental studies. table 1 reports a summary of np behaviors on drilling fluids. the goal of this experiment is to examine the performance of water-based nano muds containing al2o3 nps and fe2o3 nps and compare them to lignosulfonate water-based muds (wbm). a series of lab tests were used to conduct this evaluation. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2022.4.4 h. a. abbood and i. k. shakir / iraqi journal of chemical and petroleum engineering 23,4 (2022) 25 32 26 table 1. summary of nanoparticle behaviors on drilling fluids nanoparticle types outcomes references sio2 proved the rheological and fluid loss properties. improved the shale inhibition. significant reduction in filtration . [10] [11] [12] laponite enhancement of thermal stability. [13] tio2 improves the thermal stability and rheological properties. [14] α-mno2 minimizing the filtration loss. [15] zno improved the rheological behaviors and provided better filtration control. [16] al2o3 improved the effective thermal conductivity. improve the rheological properties. [17] [18] fe2o3 developments rheological and fluid loss properties. improved filter cake and fluid loss. [19] [20] 2experimental work 2.1. characterization of the materials al2o3 and fe2o3 are two of the most widely used nps because of their heat transfer properties and low cost. for this study, fe2o3 and al2o3 nps were chosen as a result. nanjing nano technology and sky spring nps, respectively, served as the suppliers of al2o3 and fe2o3. nanoparticle properties are listed in table 2 and table 3. al2o3 and fe2o3 np morphology is shown in fig. 1 and fig. 2 tem and sem images, respectively. table 2. physical properties of fe2o3 nps properties typical value purity 99.9% appearance black powder size 20-30 nm ash >0.2 wt.% table 3. physical properties of al2o3 nps fig. 1. tem images of al2o3nps fig. 2. sem images of fe2o3nps 2.2. methodology the drilling fluid utilized in this study is ferro chrome lignosulphonate (fcl), which is commonly employed in southern iraqi oil fields. this mud is simple and quick to prepare. according to api standards, bentonite fluid should be prehydrated by mixing 20 grams of sodium bentonite with 350 milliliters of fresh water for at least 20 minutes using a hamilton beach mixer and letting it sit for 16 hours. then, add 0.5 g of caustic soda to improve the performance of lignosulphonate and raise the ph values. also 1g of soda ash is used to remove the calcium ion and improve the properties of calcium bentonite. lignosulfonate is used to deflocculate and control the rheology of 1g of bentonite. the mixture is then mixed for 20 minutes using a hamilton beach mixer under laboratory conditions, where the concentrations of al2o3 and fe2o3 nps range from 0 to 1g. the fluid is then placed in an ultrasonic bath for 15 minutes to ensure that the nano particles are evenly distributed throughout the fluid and experimental work flowchart as showing in fig. 3. fig. 3. experimental work flowchart properties typical value purity 99.9% appearance white powder size 20 nm ash >0.2 wt.% h. a. abbood and i. k. shakir / iraqi journal of chemical and petroleum engineering 23,4 (2022) 25 32 27 2.3. rheological testing plastic viscosity, gel strength, filter cake thickness and filtrate loss were some of the rheological properties studied for the prepared muds. mud viscosity and gel strength (10 sec and 10 min) were measured using a vang meter. the api standard was used to measure the parameters of plastic viscosity (pv) and yield point (yp). the van-g meter was used to determine the pv and yield point values at both 300rpm and 600rpm motor speeds. the filter cake was evaluated, and the filtration loss was calculated in a filter press with the help of this tool. filter press pressurized cells contain a pressurized filter medium. to a nitrogen gas cylinder was connected to the filter press equipment in order to raise the cell pressure to 100 psi. it took about 30 minutes for each of the tests, and there were two of them. afterwards, the cell was disassembled and the mud thrown away. to avoid damaging the mud cake, be sure to take your time and be cautious when removing the components from the cake. the cake was gently scrubbed to remove any remaining mud before serving. as a final step, the filter cake thickness was measured and recorded in 1/32-inch increments. to be clear, all tests were performed at 27 °c. equations are used to calculate (pv) and (yp) [29]: pv= 𝜃600 − 𝜃300 (1) yp=𝜃300 − 𝑃𝑉 (2) whereas φ600 = dial reading at 600 rpm, and φ300 = dial reading at 300 rpm. 2.4. lubricity extreme pressure/lubricity testers were used to measure cof for the lubricity test. drill string and wellbore are analogous in that they are made of metal to metal. it was possible to calculate lubricity with this formula [23]: cof = torque reading 100 (3) 100= 150 inch−ibs torque wrench reading 1.5 inch torque shaft lever arm (4) cf = meter reading for water (standerd) meter reading obtained in water calbration (5) cof = (meter reading for water )(cf) 100 (6) whereas, cof = coefficient of fraction, and cf= coefficient factor. 2.5. shale swelling testing drilling mud compatibility with the wellbore should be determined before operations begin. the interaction of the shale with the drilling muds is the method to test the shale's compatibility with the swelling process. in this studies, we used a compactor cell to create shale plugs for a swelling analysis. swelling test procedure for shale is provided [11]. 3results and discussion 3.1. properties of rheology a. plastic viscosity due to the difficulty of pumping drilling fluid with a high pv, drillers avoid using it for drilling operations. drilling fluid density, on the other hand, is directly related to mud viscosity and should be considered when designing a drilling fluid. for this reason, lower mud viscosity results in less dense water due to a reduction in hydrostatic pressure, which isn't always a good thing [22]. the pv of lignosulfonate-wbm was found to be only 7 cp. as shown in fig. 4, the addition of nps to lignosulfonate wbm generally increased the pv. however, the pv amounts at various concentrations of each np type vary (from 0 to 1 g) was different. in addition, 1 g of al2o3 nps was added to increase the amount of pv to 8 cp. the al2o3 nps are dispersed throughout the fluid uniformly; the mud's viscosity may rise due to an increase in interlayer friction [19]. we were able to achieve 8 cp of pv by mixing in 0. 5 g fe2o3 nps with the base mud. when the concentration was increased to 0.5 g, the pv remained constant at 8 cp before increasing to 9 cp at the 1 g concentration point. fig. 4. nps concentration affects by plastic viscosity (cp) b. yield point mud-cutting capacity can be determined by taking into account the yp value, which is an important factor make it easier to transport heavier cutting [8]. we found that based lignosulfonate -wbm had a yield point of 9 lb/100ft2. it is shown in that nps affect the yield point of linosulfonate -wbms in fig. 5, at different np concentrations, the yp of wbm with linosulfonate wbm shows different results. the yp of al2o3 np lignosulfonate -wbm increases at all concentrations. at h. a. abbood and i. k. shakir / iraqi journal of chemical and petroleum engineering 23,4 (2022) 25 32 28 a concentration of 1 g of al2o3 np lignosulfonate-wbm, the maximum yp was 55 lb/100 ft2. yield point values risen sharply for fe2o3 nps, reaching 38 lb/100 ft 2 at 1g. since al2o3 nps have a higher surface-to-volume ratio at 1 g, they will interact more strongly with the base fluid around them, leading to a higher yp [25]. fig. 5. nps concentration affects the yield point c. gel strength the gel strength of the drilling fluids must be maintained at a relatively high level in order to suspend and transport cuttings in horizontal wells. reduced wbm circulation circulating pressure loss also contributes to improved drilling efficiency [26]. it is a standard. under static conditions, the electrochemical forces in the fluid determine the gel strength. fig. 6 and fig. 7, the influence of nps at various concentrations on gs is demonstrated at 10 s and 10 min, respectively. base mud gel strength was determined to be 7 and 12 lb/100 ft2 for 10 sec and 10 min, respectively, in the initial test. the addition of al2o3 nps ranging from 0.25 to 1 g increased the lignosulfonate wbm gel strength values in both tests (10 sec and 10 min). a concentration of 1 g al2o3 nps produced a lignosulfonate-wbm 10 sec gel strength of 53 lb/100 ft2 and a 10 min gel strength of 58 lb/100 ft2. in the presence of fe2o3 nps, the 10 sec and 10-min gel strength values increased by addition nps from 0.25 to 1g. fe2o3 nps, on the other hand, increased the 10 sec and 10 min gel strength values to 40 and 50 lb/100 ft2 respectively. the high gelling characteristics of the fluid may necessitate a high starting torque, which must be justified by investigating the fluid's shear thinning behavior. the absence of numerous and serious drilling issues can only be ensured by using a high-strength gel [27]. finally, the gelling properties of al2o3 nps at 1g concentration are superior to those of fe2o3 nps, due to the electrostatic force between al2o3nps, which links their cases with base fluids to create a rigid structure, this happens [18]. fig. 6. nps concentration effects on gel strength over a 10-sec fig. 7. nps concentration effects on gel strength over a 10-min 3.2. loss of filtering wellbore plugging, formation expansion, and wellbore instability and collapse can all be caused by fluid outflow into the formation. differential pressure adhesion, caused by cake buildup on the wellbore wall, increases the risk of drilling tool damage [28]. in order to prevent drilling fluid from escaping and entering a formation, nps can be used to obstruct the pore space [7]. fig. 8, shows the fluid loss behavior of lignosulfonete-wbm with varying np concentrations. the lignosulfonete-wbm lost 13.5 ml of fluid after 30 minutes. the fluid loss volume was reduced to 9.3 ml after incorporating al2o3 nps into the wbm at a concentration of 1 g. in general, al2o3 nps are a good additive for lowering the filter loss of lignosulfonete-wbm. the addition of 1g of fe2o3 nps reduced the lignosulfonete-wbm filter losses to 8.6 ml. base mud fluid loss can be reduced by using 1g of fe2o3nps. however, fe2o3 nps are a better choice for reducing fluid loss, this finding concur well with [9]. h. a. abbood and i. k. shakir / iraqi journal of chemical and petroleum engineering 23,4 (2022) 25 32 29 fig. 8. nps concentration affects the filtrate (ml) 3.3. lubricity and nps concentration a lot of heat and friction is generated during drilling operations at the bit and the drill string/wellbore interface. in addition, when the drill string is rotating, the friction that occurs between the wellbore and the drill string can generate a significant amount of torque and drag [29]. it is one of the primary functions of drilling fluid to lubricate the drill string as it progresses through the well. to determine a surface's coefficient of friction, you must first determine how much traction there is between the two objects [23]. fig. 9, a small amount of nanoparticles in the drilling fluid reduced cof slightly, according to the results of this study. using base mud, we were able to increase torque by about 44%. in contrast, the addition of fe2o3 and al2o3 nps led to a torque reduction of 33% and 31%, respectively, at a concentration of 0.75 g. similar to fe2o3 nps, al2o3 nps above 0.75 g caused 35% and 37% increase in cof, respectively. wbm lignosulfonete crushes under rotation and forms angulated forms, resulting in higher cof values than fe2o3 and al2o3 nps. nps reduce the cof by creating a slippery layer between the drill string and the borehole. fig. 9. friction of coefficient (cof) depends on the concentration of nps in the fluid 3.4. swelling behavior and nanoparticle effects by far and away the most common result of freshwater intrusion is the alteration of clay minerals. when clays in the rock matrix are hydrated and swelled by water, they can become dispersed and cause particle plugging. the clay mineral smectite or montmorillonite is the most important one for swelling. interlayer adsorption of water has the capability of expanding this clay up to a 10-fold range. this depends on the cation in the interlayer [30]. wbm with the nps. because of the synergetic properties of nps, to expand, it means that the bentonite in the nps system absorbed less water, resulting in less clay swelling and increased shale strength [24]. fig. 10, show the expansion quantity meter results for the sodium bentonite shale, using four different drilling fluids, including fresh water, al2o3 nps, fe2o3 nps, and lignosulfonete-wbm. after 15 hours in fresh water, the bentonite had grown by 15% and the lignosulfonete-wbm had grown by 13%. al2o3-np-treated lignosulfonete-wbm grew by less than 7% after 16 hours of exposure to these systems. finally, the addition of fe2o3 nps reduces swelling to 8% due to nps' ability to plug nano pores in clay, preventing shale swelling. as a result, al2o3 nps are the most effective additive for reducing lignosulfonete-wbm swelling [11]. fig. 10. shale interacted with liginosulfonate-wbm /al2o3, fe2o3 nps and compared with basic muds 4conclusion shale plug immersed in al2o3 nps mud shows less erosion and cracking along the boundary and at the center of the shale plug compared to basic mud, however, al2o3 nps mud system shows good shale inhibition compared to fe2o3 nps mud system. overall, the results showed that the addition of al2o3and fe2o3 nps to the basic mud system improved shale inhibition and rheological properties. api and lplt filtrate volumes were minimized by using al2o3and fe2o3 nps. minimizing cof with al2o3and fe2o3 nps. however, further studies are required to investigate the effect of al2o3and fe2o3 nps at higher concentrations over shale swelling and rheological behavior of the muds. h. a. abbood and i. k. shakir / iraqi journal of chemical and petroleum engineering 23,4 (2022) 25 32 30 references [1] m. s al ruqeishi, y. al salmi and t. mohiuddi, (2018). “nanoparticles as drilling fluids rheological properties modifiers”, progress petrochem science, vol.1 issue – 5. [2] m. s.al-yasiri and w.t. al-sallami, (2015). “how the drilling fluids can be made more efficient by using nanomaterials”, american journal of nano research and applications, vol. 3, no. 3, pp. 41-45. [3] s. livescu, (2012).” mathematical modeling of thixotropic drilling mud and crude oil flow in wells and pipelines—a review”, journal of petroleum science and engineering, vol.98-99, pp.174-184. [4] ayad a.alhaleem a.alrazzaq, h. a. neamah,(2018). “torque and drag forces problems in highly deviated oil well”, iraqi journal of chemical and petroleum engineering, vol.19 no.3, 19 – 31. [5] amel habeeb assi, (2018). “potato starch for enhancing the properties of the drilling fluids”, iraqi journal of chemical and petroleum engineering, vol.19 no.3, 33 –40. [6] f. h. m. almahdawi, a. zarzor al-yaseri and n. jasi, (2014).” apparent viscosity direct from marsh funnel test”, iraqi journal of chemical and petroleum engineering, vol.15 no.1, pp.5157. [7] ahmed r. albajalan and hunar k. haias, (2021). “evaluation of the performance of conventional water-based mud characteristics by applying zinc oxide and silica dioxide nanoparticle materials for a selected well in the kurdistan/iraq oil field”, advances in materials science and engineering, id 4376366, pp. 10. [8] v. srivastava, (2021). “application of manganese oxide nanoparticles synthesized via green route for improved performance of water based drilling fluids”, applied nanoscience, vol. 11, pp.2247– 2260. [9] g. cheraghian, (2021). “nanoparticles in drilling fluid: a review of the state-of-the-art”, journal of materials research and technology, vol.13, 737-753. [10] g. cheraghian, q. wu, m. mostofi, m. c. li, m. afrand, and j. s. sangwai, “effect of a novel clay/silica nanocomposite on water-based drilling fluids: improvements in rheological and filtration properties,” colloids surfaces a physicochem. eng. asp., vol. 555, pp. 339–350, oct. 2018. [11] a. aftab, a. r. ismail, and z. h. ibupoto, “enhancing the rheological properties and shale inhibition behavior of water-based mud using nanosilica, multi-walled carbon nanotube, and graphene nanoplatelet,” egypt. j. pet., vol. 26, no. 2, pp. 291–299, jun. 2017, doi: 10.1016/j.ejpe.2016.05.004. [12] a. v. minakov, e. i. mikhienkova, y. o. voronenkova, a. l. neverov, g. m. zeer, and s. m. zharkov, “systematic experimental investigation of filtration losses of drilling fluids containing silicon oxide nanoparticles,” j. nat. gas sci. eng., vol. 71, nov. 2019, doi: 10.1016/j.jngse.2019.102984. [13] x. huang et al., “enhancement of thermal stability of drilling fluid using laponite nanoparticles under extreme temperature conditions,” mater. lett., vol. 248, pp. 146–149, aug. 2019. [14] m. beg, p. kumar, p. choudhary, and s. sharma, “effect of high temperature ageing on tio2 nanoparticles enhanced drilling fluids: a rheological and filtration study,” upstream oil gas technol., vol. 5, oct. 2020, doi: 10.1016/j.upstre.2020.100019. [15] v. srivastava, m. beg, s. sharma, and a. k. choubey, “application of manganese oxide nanoparticles synthesized via green route for improved performance of water-based drilling fluids,” appl. nanosci., vol. 11, no. 8, pp. 2247– 2260, aug. 2021, doi: 10.1007/s13204-021-01956-8. [16] a. r. albajalan and h. k. haias, “evaluation of the performance of conventional water-based mud characteristics by applying zinc oxide and silica dioxide nanoparticle materials for a selected well in the kurdistan/iraq oil field,” adv. mater. sci. eng., vol. 2021, 2021, doi: 10.1155/2021/4376366. [17] m. al-yasiri and d. wen, “gr-al2o3 nanoparticlesbased multifunctional drilling fluid,” ind. eng. chem. res., vol. 58, no. 23, pp. 10084–10091, jun. 2019, doi: 10.1021/acs.iecr.9b00896. [18] m. t. al-saba, ; a al fadhli, ; a marafi, ; a hussain, ; f bander, and ; m f al dushaishi, “application of nanoparticles in improving rheological properties of water based drilling fluids,” 2018. [19] z. vryzas, “a comprehensive approach for the development of new magnetite nanoparticles giving smart drilling fluids with superior properties for hp/ ht applications,” 2016. [20] z. wang, y. wu, p. luo, y. tian, y. lin, and q. guo, “poly (sodium p-styrene sulfonate) modified fe3o4 nanoparticles as effective additives in waterbased drilling fluids,” j. pet. sci. eng., vol. 165, pp. 786–797, jun. 2018, doi: 10.1016/j.petrol.2018.03.001. [21] z.vryzas, et al.(2015). “development and testing of novel drilling fluids using fe2o3 and sio2 nanoparticles for enhanced drilling operations”, spe international oilfield nanotechnology conference, vol. 13, pp. 737-753. [22] a. e. bayat, et al. (2018). “experimental investigation of rheological and filtration properties of water-based drilling fluids in presence of various nanoparticles”, colloids and surfaces a 555, 256– 263. [23] a. r. ismail, et al. (2016). “the novel approach for the enhancement of rheological properties of waterbased drilling fluids by using multi-walled carbon nanotube, nano silica and glass beads”, journal of petroleum science and engineering, vol.139, pp.264–275. [24] al-yasiri, m., awad, a., pervaiz, s., wen, d., influence of silica nanoparticles on the functionality of water-based drilling fluids, journal of petroleum science and engineering (2019). https://d1wqtxts1xzle7.cloudfront.net/56523471/pps.000521-libre.pdf?1525874261=&response-content-disposition=inline%3b+filename%3dnanoparticles_as_drilling_fluids_rheolog.pdf&expires=1671010831&signature=gtc5qardenoazxhmpn-cicxbrnmdcsv1b~zh6auve6wmzi5jjwfiiyfoljrqd21p9eoh-nhcvx-f-uipywz6prfzbkc0xiltgbhtrjpkuzpkmt5ssvyluhyfxzp~g~twomizlsnedrkgsozn9gga8gma~veyu0ynohor-w581kujd6wv0zzjtlvq0wftgi-cxegv5bfelxbjgg1txuhkatdvaox3unszbijuu8cttzhaklbqs-iqtjha6ne8gipk1uwytbtzmdcn7lthnq3imkelznevgiv-bn5gjpkbj48ddgs03ss4y5vd2eh-mzrcnhqwecbnufqicr6mv7nypa__&key-pair-id=apkajlohf5ggslrbv4za https://d1wqtxts1xzle7.cloudfront.net/56523471/pps.000521-libre.pdf?1525874261=&response-content-disposition=inline%3b+filename%3dnanoparticles_as_drilling_fluids_rheolog.pdf&expires=1671010831&signature=gtc5qardenoazxhmpn-cicxbrnmdcsv1b~zh6auve6wmzi5jjwfiiyfoljrqd21p9eoh-nhcvx-f-uipywz6prfzbkc0xiltgbhtrjpkuzpkmt5ssvyluhyfxzp~g~twomizlsnedrkgsozn9gga8gma~veyu0ynohor-w581kujd6wv0zzjtlvq0wftgi-cxegv5bfelxbjgg1txuhkatdvaox3unszbijuu8cttzhaklbqs-iqtjha6ne8gipk1uwytbtzmdcn7lthnq3imkelznevgiv-bn5gjpkbj48ddgs03ss4y5vd2eh-mzrcnhqwecbnufqicr6mv7nypa__&key-pair-id=apkajlohf5ggslrbv4za https://d1wqtxts1xzle7.cloudfront.net/56523471/pps.000521-libre.pdf?1525874261=&response-content-disposition=inline%3b+filename%3dnanoparticles_as_drilling_fluids_rheolog.pdf&expires=1671010831&signature=gtc5qardenoazxhmpn-cicxbrnmdcsv1b~zh6auve6wmzi5jjwfiiyfoljrqd21p9eoh-nhcvx-f-uipywz6prfzbkc0xiltgbhtrjpkuzpkmt5ssvyluhyfxzp~g~twomizlsnedrkgsozn9gga8gma~veyu0ynohor-w581kujd6wv0zzjtlvq0wftgi-cxegv5bfelxbjgg1txuhkatdvaox3unszbijuu8cttzhaklbqs-iqtjha6ne8gipk1uwytbtzmdcn7lthnq3imkelznevgiv-bn5gjpkbj48ddgs03ss4y5vd2eh-mzrcnhqwecbnufqicr6mv7nypa__&key-pair-id=apkajlohf5ggslrbv4za https://d1wqtxts1xzle7.cloudfront.net/56523471/pps.000521-libre.pdf?1525874261=&response-content-disposition=inline%3b+filename%3dnanoparticles_as_drilling_fluids_rheolog.pdf&expires=1671010831&signature=gtc5qardenoazxhmpn-cicxbrnmdcsv1b~zh6auve6wmzi5jjwfiiyfoljrqd21p9eoh-nhcvx-f-uipywz6prfzbkc0xiltgbhtrjpkuzpkmt5ssvyluhyfxzp~g~twomizlsnedrkgsozn9gga8gma~veyu0ynohor-w581kujd6wv0zzjtlvq0wftgi-cxegv5bfelxbjgg1txuhkatdvaox3unszbijuu8cttzhaklbqs-iqtjha6ne8gipk1uwytbtzmdcn7lthnq3imkelznevgiv-bn5gjpkbj48ddgs03ss4y5vd2eh-mzrcnhqwecbnufqicr6mv7nypa__&key-pair-id=apkajlohf5ggslrbv4za https://scholar.google.com/scholar?hl=en&as_sdt=0%2c5&q=%5b2%5d%09m.+s.al-yasiri+and+w.t.+al-sallami%2c+%282015%29.+%e2%80%9chow+the+drilling+fluids+can+be+made+more+efficient+by+using+nanomaterials%e2%80%9d%2c+american+journal+of+nano+research+and+applications%2c+vol.+3%2c+no.+3%2c+pp.+41-45.&btng= https://scholar.google.com/scholar?hl=en&as_sdt=0%2c5&q=%5b2%5d%09m.+s.al-yasiri+and+w.t.+al-sallami%2c+%282015%29.+%e2%80%9chow+the+drilling+fluids+can+be+made+more+efficient+by+using+nanomaterials%e2%80%9d%2c+american+journal+of+nano+research+and+applications%2c+vol.+3%2c+no.+3%2c+pp.+41-45.&btng= https://scholar.google.com/scholar?hl=en&as_sdt=0%2c5&q=%5b2%5d%09m.+s.al-yasiri+and+w.t.+al-sallami%2c+%282015%29.+%e2%80%9chow+the+drilling+fluids+can+be+made+more+efficient+by+using+nanomaterials%e2%80%9d%2c+american+journal+of+nano+research+and+applications%2c+vol.+3%2c+no.+3%2c+pp.+41-45.&btng= https://scholar.google.com/scholar?hl=en&as_sdt=0%2c5&q=%5b2%5d%09m.+s.al-yasiri+and+w.t.+al-sallami%2c+%282015%29.+%e2%80%9chow+the+drilling+fluids+can+be+made+more+efficient+by+using+nanomaterials%e2%80%9d%2c+american+journal+of+nano+research+and+applications%2c+vol.+3%2c+no.+3%2c+pp.+41-45.&btng= https://www.sciencedirect.com/science/article/abs/pii/s0920410512001179 https://www.sciencedirect.com/science/article/abs/pii/s0920410512001179 https://www.sciencedirect.com/science/article/abs/pii/s0920410512001179 https://www.sciencedirect.com/science/article/abs/pii/s0920410512001179 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/7 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/7 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/7 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/7 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/8 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/8 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/8 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/8 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/268 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/268 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/268 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/268 https://www.hindawi.com/journals/amse/2021/4376366/ https://www.hindawi.com/journals/amse/2021/4376366/ https://www.hindawi.com/journals/amse/2021/4376366/ https://www.hindawi.com/journals/amse/2021/4376366/ https://www.hindawi.com/journals/amse/2021/4376366/ https://www.hindawi.com/journals/amse/2021/4376366/ https://www.hindawi.com/journals/amse/2021/4376366/ https://link.springer.com/article/10.1007/s13204-021-01956-8 https://link.springer.com/article/10.1007/s13204-021-01956-8 https://link.springer.com/article/10.1007/s13204-021-01956-8 https://link.springer.com/article/10.1007/s13204-021-01956-8 https://link.springer.com/article/10.1007/s13204-021-01956-8 https://www.sciencedirect.com/science/article/pii/s2238785421004336 https://www.sciencedirect.com/science/article/pii/s2238785421004336 https://www.sciencedirect.com/science/article/pii/s2238785421004336 https://www.sciencedirect.com/science/article/abs/pii/s0927775718305879 https://www.sciencedirect.com/science/article/abs/pii/s0927775718305879 https://www.sciencedirect.com/science/article/abs/pii/s0927775718305879 https://www.sciencedirect.com/science/article/abs/pii/s0927775718305879 https://www.sciencedirect.com/science/article/abs/pii/s0927775718305879 https://www.sciencedirect.com/science/article/abs/pii/s0927775718305879 https://www.sciencedirect.com/science/article/pii/s1110062116300137 https://www.sciencedirect.com/science/article/pii/s1110062116300137 https://www.sciencedirect.com/science/article/pii/s1110062116300137 https://www.sciencedirect.com/science/article/pii/s1110062116300137 https://www.sciencedirect.com/science/article/pii/s1110062116300137 https://www.sciencedirect.com/science/article/pii/s1110062116300137 https://www.sciencedirect.com/science/article/pii/s1110062116300137 https://www.sciencedirect.com/science/article/abs/pii/s1875510019302367 https://www.sciencedirect.com/science/article/abs/pii/s1875510019302367 https://www.sciencedirect.com/science/article/abs/pii/s1875510019302367 https://www.sciencedirect.com/science/article/abs/pii/s1875510019302367 https://www.sciencedirect.com/science/article/abs/pii/s1875510019302367 https://www.sciencedirect.com/science/article/abs/pii/s1875510019302367 https://www.sciencedirect.com/science/article/abs/pii/s0167577x19305543 https://www.sciencedirect.com/science/article/abs/pii/s0167577x19305543 https://www.sciencedirect.com/science/article/abs/pii/s0167577x19305543 https://www.sciencedirect.com/science/article/abs/pii/s0167577x19305543 https://www.sciencedirect.com/science/article/abs/pii/s2666260420300190 https://www.sciencedirect.com/science/article/abs/pii/s2666260420300190 https://www.sciencedirect.com/science/article/abs/pii/s2666260420300190 https://www.sciencedirect.com/science/article/abs/pii/s2666260420300190 https://www.sciencedirect.com/science/article/abs/pii/s2666260420300190 https://link.springer.com/article/10.1007/s13204-021-01956-8 https://link.springer.com/article/10.1007/s13204-021-01956-8 https://link.springer.com/article/10.1007/s13204-021-01956-8 https://link.springer.com/article/10.1007/s13204-021-01956-8 https://link.springer.com/article/10.1007/s13204-021-01956-8 https://link.springer.com/article/10.1007/s13204-021-01956-8 https://www.hindawi.com/journals/amse/2021/4376366/ https://www.hindawi.com/journals/amse/2021/4376366/ https://www.hindawi.com/journals/amse/2021/4376366/ https://www.hindawi.com/journals/amse/2021/4376366/ https://www.hindawi.com/journals/amse/2021/4376366/ https://www.hindawi.com/journals/amse/2021/4376366/ https://pubs.acs.org/doi/abs/10.1021/acs.iecr.9b00896 https://pubs.acs.org/doi/abs/10.1021/acs.iecr.9b00896 https://pubs.acs.org/doi/abs/10.1021/acs.iecr.9b00896 https://pubs.acs.org/doi/abs/10.1021/acs.iecr.9b00896 https://onepetro.org/spesats/proceedings-abstract/18sats/all-18sats/spe-192239-ms/215529 https://onepetro.org/spesats/proceedings-abstract/18sats/all-18sats/spe-192239-ms/215529 https://onepetro.org/spesats/proceedings-abstract/18sats/all-18sats/spe-192239-ms/215529 https://onepetro.org/spesats/proceedings-abstract/18sats/all-18sats/spe-192239-ms/215529 https://onepetro.org/spesats/proceedings-abstract/18sats/all-18sats/spe-192239-ms/215529 https://onepetro.org/iptconf/proceedings-abstract/16iptc/3-16iptc/d031s053r001/153940 https://onepetro.org/iptconf/proceedings-abstract/16iptc/3-16iptc/d031s053r001/153940 https://onepetro.org/iptconf/proceedings-abstract/16iptc/3-16iptc/d031s053r001/153940 https://onepetro.org/iptconf/proceedings-abstract/16iptc/3-16iptc/d031s053r001/153940 https://www.sciencedirect.com/science/article/abs/pii/s0920410518301852 https://www.sciencedirect.com/science/article/abs/pii/s0920410518301852 https://www.sciencedirect.com/science/article/abs/pii/s0920410518301852 https://www.sciencedirect.com/science/article/abs/pii/s0920410518301852 https://www.sciencedirect.com/science/article/abs/pii/s0920410518301852 https://www.sciencedirect.com/science/article/abs/pii/s0920410518301852 https://onepetro.org/iptconf/proceedings-abstract/15iptc/4-15iptc/d041s044r002/153630 https://onepetro.org/iptconf/proceedings-abstract/15iptc/4-15iptc/d041s044r002/153630 https://onepetro.org/iptconf/proceedings-abstract/15iptc/4-15iptc/d041s044r002/153630 https://onepetro.org/iptconf/proceedings-abstract/15iptc/4-15iptc/d041s044r002/153630 https://onepetro.org/iptconf/proceedings-abstract/15iptc/4-15iptc/d041s044r002/153630 https://www.sciencedirect.com/science/article/abs/pii/s0927775718306046 https://www.sciencedirect.com/science/article/abs/pii/s0927775718306046 https://www.sciencedirect.com/science/article/abs/pii/s0927775718306046 https://www.sciencedirect.com/science/article/abs/pii/s0927775718306046 https://www.sciencedirect.com/science/article/abs/pii/s0927775718306046 https://www.sciencedirect.com/science/article/abs/pii/s0920410516300365 https://www.sciencedirect.com/science/article/abs/pii/s0920410516300365 https://www.sciencedirect.com/science/article/abs/pii/s0920410516300365 https://www.sciencedirect.com/science/article/abs/pii/s0920410516300365 https://www.sciencedirect.com/science/article/abs/pii/s0920410516300365 https://www.sciencedirect.com/science/article/abs/pii/s0920410516300365 https://www.sciencedirect.com/science/article/abs/pii/s0920410519304188 https://www.sciencedirect.com/science/article/abs/pii/s0920410519304188 https://www.sciencedirect.com/science/article/abs/pii/s0920410519304188 https://www.sciencedirect.com/science/article/abs/pii/s0920410519304188 h. a. abbood and i. k. shakir / iraqi journal of chemical and petroleum engineering 23,4 (2022) 25 32 31 [25] f. h. m. al-mahdawi and k. saad, (2018). “enhancement of drilling fluid properties using nanoparticles”, iraqi journal of chemical and petroleum engineering, vol.19 no.2, 21 – 26. [26] k. wang et al. (2018). “magnesium aluminum silicate nanoparticles as a high-performance rheological modifier in water-based drilling fluids”, applied clay science, vol.161, no.1, pp. 427-435. [27] r.ghosn, et al. (2017). “silica nanoparticles for the stabilization of w/o emulsions at hthp conditions for unconventional reserves drilling operations”, oil gas sci. technol , vol. 72, no.4 ,pp.13-21. [28] j. sun, et al. (2020). “salt-responsive zwitterm ionic polymer brush based on modified silica nanoparticles as a fluid-loss additive in waterbased drilling fluids”, energy & fuels, vol.34, no.2, pp.1669-1679. [29] "drilling fluids manual", amoco production company. [30] “drilling fluids reference manual”, buker hughes. https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/162 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/162 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/162 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/162 https://www.sciencedirect.com/science/article/abs/pii/s0169131718302254 https://www.sciencedirect.com/science/article/abs/pii/s0169131718302254 https://www.sciencedirect.com/science/article/abs/pii/s0169131718302254 https://www.sciencedirect.com/science/article/abs/pii/s0169131718302254 https://ogst.ifpenergiesnouvelles.fr/articles/ogst/abs/2017/04/ogst160178/ogst160178.html https://ogst.ifpenergiesnouvelles.fr/articles/ogst/abs/2017/04/ogst160178/ogst160178.html https://ogst.ifpenergiesnouvelles.fr/articles/ogst/abs/2017/04/ogst160178/ogst160178.html https://ogst.ifpenergiesnouvelles.fr/articles/ogst/abs/2017/04/ogst160178/ogst160178.html https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.9b04109 https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.9b04109 https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.9b04109 https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.9b04109 https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.9b04109 h. a. abbood and i. k. shakir / iraqi journal of chemical and petroleum engineering 23,4 (2022) 25 32 32 بإضافة نانو أوكسيد االلمنيوم lignosulfonete mud)تحسين خواص طين الحفر ) واوكسيد الحديد حسن علي عبود و ابتهال كريم شاكر قسم الهندسة الكيمياوية/كلية الهندسة/جامعة بغداد الخالصة لها النفطية ك لجدار البئر، والتحكم في الترشيح لسائل حفر االباران الخواص االنسيابية، والتزييت، واالنتفاخ ، خواص مهمة يجب مراعاتها قبل البدء بعملية حفر البئر النفطي. حيث يمكن جعل تلك السوائل أكثر سالسة ك يمكنفعالية واقل كلفة من خالل إضافات مواد نانوية والتي تعرف بأوكسيد االلمنيوم واوكسيد الحديد. وكذل ة، تقييم أداء تلك السائل من خالل مقارنة خصائصه األساسية مع تلك الخصائص المحسنة باإلضافات النانوي دون سائل الحفر بغم(. وفقًا للنتائج، وجد ان 1.و0.25,0.5,0.75حيث تكون تلك اإلضافات بتراكيز مختلفة ) غم 0.75ز كسيد الحديد( وبتركياللمنيوم واو ، بينما مع النانو )اوكسيد ا%44النانو يمتلك معامل احتكاك بنسبة على التوالي. وكذلك استطاع النانو )اوكسيد االلمنيوم واوكسيد %33و %31معامل االحتكاك بنسبة قل تفاخ على التوالي. وكذلك تم تحسين الخواص االنسيابية وتقليل االن %37و %30الحديد( تقليل الراشح بنسبة غم استطاع تحسين1ك النانو. الخالصة، ان استخدام النانو وخاصة عن تركيز غم من تل1وخاصة عند تركيز غم. 0.75الخواص االنسيابية والترشيح واالنتفاخ باإلضافة الى التزييت عند تركيز ، التزييت، الترشيح، االنتفاخ.حبيبات نانوية، طين الحفر :ةلادالكلمات ال iraqi journal of chemical and petroleum engineering vol.17 no.1 (march 2016) 111 issn: 1997-4884 permeability prediction in one of iraqi carbonate reservoir using hydraulic flow units and neural networks dahlia abdulhadi alobaidi university of baghdad, petroleum engineering department abstract permeability determination in carbonate reservoir is a complex problem, due to their capability to be tight and heterogeneous, also core samples are usually only available for few wells therefore predicting permeability with low cost and reliable accuracy is an important issue, for this reason permeability predictive models become very desirable. this paper will try to develop the permeability predictive model for one of iraqi carbonate reservoir from core and well log data using the principle of hydraulic flow units (hfus). hfu is a function of flow zone indicator (fzi) which is a good parameter to determine (hfus). histogram analysis, probability analysis and log-log plot of reservoir quality index (rqi) versus normalized porosity (øz) are presented to identify optimal hydraulic flow units. four hfus were distinguished in this study area with good correlation coefficient for each hfu (r 2 =0.99), therefore permeability can be predicted from porosity accurately if rock type is known. conventional core analysis and well log data were obtained in well 1 and 2 in one of carbonate iraqi oil field. the relationship between core and well log data was determined by artificial neural network (ann) in cored wells to develop the predictive model and then was used to develop the flow units prediction to un-cored wells. finally permeability can be calculated in each hfu using effective porosity and mean fzi in these hfus. validation of the models evaluated in a separate cored well (blind-test) which exists in the same formation. the results showed that permeability prediction from ann and hfu matched well with the measured permeability from core data with r 2 =0.94 and are= 1.04%. key words: permeability prediction, flow zone indicator, hydraulic flow unit, artificial neural network. introduction reservoir characterization methods are very important to provide a better attributive of the flow capacities and storage of petroleum reservoir. carbonate reservoirs show challenges in characterization because of their heterogeneity and tendency to be tight due to depositional and digenetic processes [1]. permeability estimation in a logged but uncored wells/intervals is a generic problem to all reservoirs. models based on hfu which is a iraqi journal of chemical and petroleum engineering university of baghdad college of engineering permeability prediction in one of iraqi carbonate reservoir using hydraulic flow units and neural networks 2 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net function of fzi are more recommended to predict permeability than traditional regression because they provide more reliable accuracy and precise models for entire reservoir by dividing the reservoir into various flow units different from the other by means of characters controlling fluid flow in reservoir[2]. fzi is depending on geological description of the material and various pore geometry of rock mass (reservoir quality index (rqi) and normalized porosity (øz)). fzi is a useful value that offers a relationship between petrophysical properties at the macroscopic scale like core plugs with mega scale which is represented by the wireline-log measurement scale. rqi and øz can be determined from core permeability and effective porosity. recently, intelligent techniques like artificial neural network (ann) have achieved considerable attention in several areas of geosciences. the oil and gas industry has shown an interest to use these techniques to solve difficult problems and enhance the accuracy of reservoir properties prediction. the main goal of this study is finding the best accurate model for characterization the reservoir. values of fzi for uncored well can be calculated using ann and well log data as input variables. determination of hydraulic flow unit (hfu) hydraulic flow unit concept proposed by amaefule et al [2] to be used as a principle for subdividing reservoir in different rock types. hfu represent volume of reservoir rock when the petrophysical and geological properties within it are different from properties of other rock volumes [3]. each distinct reservoir flow unit has a unique fzi which represents the relationship between reservoir quality index (rqi) which represent geometric distribution of pore space and the normalized porosity (øz). √ … (1) where k is the permeability in md rqi is reservoir quality index in μm øe is effective porosity in fraction ( ) ... (2) where øz is the pore volume to grain volume ratio or normalized porosity the fzi is defined by … (3) where fzi is flow zone indicator in μm take the logarithm of both sides of equation (3) log rqi=log øz+log fzi ... (4) on a log –log plot of rqi versus øz all samples that have similar fzi values will lie on a straight line with unit slope. samples with different fzi values will lie on other parallel lines. the intercept of the unit slope straight line at øz =1 represents the mean value of fzi. samples that lie on the same straight line have similar pore throat attributes and constitute a flow unit [2]. the number of hydraulic flow units determination in carbonate reservoirs or heterogeneous reservoirs, the data is more scattered and recognizing the straight lines and the boundaries of flow units through these scattered data and is more difficult. to determine the exact boundary of each hydraulic flow unit, three different ways were applied dahlia abdulhadi alobaidi -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 3 and compared the results that was obtained [3,4, 5, 6 and 7]. 1-histogram analysis the data of fzi plotted in the form of histogram, “n” number of normal distribution for “n” number of hfus will be obtained because fzi distribution is a superposition of multiple log-normal distribution, therefore a histogram of log fzi should show “n” number of normal distribution [8]. it is often difficult to separate the overlapped individual distribution from histogram plot. fig.1 shows log fzi histogram for well1 2-probability plot the probability plot or cumulative distribution function (cdf) is the integral of probability density function (pdf) or histogram. this plot is more useful to determine hfus because it is smoother than the histogram and identification the number of hfus becomes easier. the number of straight lines in the probability plot is an indication of hfu in the reservoir. fig.2 shows the logarithm of fzi probability plot for well 1, four hfus were distinguish. fig. 1, log fzi histogram for well1 fig.2, the logarithm of fzi probability plot for well 1 permeability prediction in one of iraqi carbonate reservoir using hydraulic flow units and neural networks 4 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net 3-loglog plot of rqi versus øz this method is a simple analysis but in this method the number of hfus and their boundaries is clearly not sufficient to distinguish. the loglog plot of rqi versus øz will produce a number of parallel straight lines with a unit slope for each one. samples that lie on the same straight line have the same pore throat attributes and thereby constitute a hydraulic unit [2]. the mean value of fzi for each hfu can be distinguished from the intercept of the unit slope straight line with øz =1. fig.3 shows the plot of rqi versus øz in logarithmic scale, four hfus were identified which means there are four rock types exist in the studied reservoir. hfu1 with fzi mean equals 0.11, hfu2 with fzi mean equals 0.28, hfu3 with fzi mean equals 0.6 and hfu4 with fzi mean equals 3. these intercept values (fzi mean ) are used to calculated permeability from the following equation. k=1014(fzimean) 2 (øe 3 /(1-øe) 2 ) …(5) the calculated permeability then plotted against the core permeability as shown in the fig.4 with average relative error (are) equals 0.55% are can be calculated from equation 6 below. ∑ | | … (6) fig. 3, the plot of rqi versus øz for well 1 0.01 0.1 1 10 0.01 0.1 1 hfu1 hfu2 hfu3 hfu4 rqi dahlia abdulhadi alobaidi -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 5 fig. 4, permeability calculated after final hfu determination vs. core permeability for well 1. fig. 5, permeability vs. porosity for well 1 0.01 0.1 1 10 100 0.01 0.1 1 10 100 p e rm e a b il it y ca lc u la te d f ro m h f u (m d ) core permeability (md) hfu1 hfu2 hfu3 hfu4 y = 43.46x3.499 r² = 0.999 y = 239.1x3.393 r² = 0.999 y = 1128x3.406 r² = 0.999 y = 128.6x1.903 r² = 0.979 0.01 0.1 1 10 100 0 0.05 0.1 0.15 0.2 0.25 0.3 p e rm e a b il it y d ri ve d f ro m h f u ( m d ) core porosity(fraction) hfu1 hfu2 hfu3 hfu4 permeability prediction in one of iraqi carbonate reservoir using hydraulic flow units and neural networks 6 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net table 1, reservoir rock classification by hfu method layer correlation coefficient(r 2 ) relation between k and ø hfu1 0.999 k=43.46 ø 3.499 hfu2 0.999 k=239.1 ø 3.393 hfu3 0.999 k=1128 ø 3.406 hfu3 0.979 k=128.6 ø 1.903 fig.5 shows the relations between permeability and porosity for each hfu and table (1) summarized these relations and given an idea about the high accuracy of hfu approach in permeability correlating with porosity. artificial neural network (ann) artificial neural network (ann) which is the most popular neural networks provides a flexible way to generalize linear regression because it does not require any relationships between variables [9]. ann is arranged in multiple layers with one input layer, one output layer and one or more hidden layers. each layer contains a number of nodes called neuron which are connected to each node in the preceding layer by simple weighted links [10]. except for nodes in the input layer, each node multiplies its specific input value by the corresponding weight and then sums all the weighted inputs [11]. flow zone indicator determination in uncored wells using artificial neural network (ann) conventional core analysis and well log data were obtained in well 1 and 2 in one of carbonate iraqi oil field, data of well 1 used for building the model then the model generalized to well 2 as uncored well for determining hfus. the artificial neural network is utilized to find the most reliable approach for hfu prediction. different models of neural networks are available and they are used for a specific purpose. in this paper feed forward back propagation neural networks technique was used. one of the major problems with this type of network is training the network using the mean square error in order to minimize the overall error. another important issue is to find the optimal number of neurons and hidden layer and select the best appropriate function [10]. for building the model in this paper, well log data including rhob, nphi, phie, ild, sfl and dt are required as input data for the (ann). to make the data uniform and prevent scattering of variables the log values must be lie between 0 and 1 to become dimensionless therefore each of these data set are normalized using equation 7 below. … (7) where: is any log value. is the minimum reading of log is the maximum reading of log is the normalized log the data set with 101 points from well 1 was divided into three sets 70% for training, 15% for testing and 15% for validation the model. each set of training data, testing and validation should be included in all wells and all the sections and subsections, also the three sets of data, including permeability data of all intervals [12]. after trial and error to obtain the best performance of the ann network, the first layer of the network (a hidden layer) consists of 20 neurons. the second layer of the network is the output layer consists of one neuron which is the logarithm of the fzi. table (2) gives the structure of the dahlia abdulhadi alobaidi -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 7 neural network to obtain the best performances of the ann model. fig.6 shows the simplified schematic of the ann used for fzi model, fig.7 shows the number of epochs with mse during the training period (best training performance). fzi determined from ann model was matched to fzi that was calculated from core permeability and effective porosity with correlation coefficient (r 2 ) of 0.96 for training, 0.99 for validation and 0.98 for testing as shown in fig.8 then the ann method was generalized to well 2 as uncored well to obtain fzi from only log data. table 2, the training networks structure for the fzi model. element fzi model the input variables 6 (rhob, nphi, phie, ild, sfl,dt) the output variable 1 (fzi) the hidden layer 1 number of neuron in hidden layer 20 performance goal (mse) 0.0000001 max. number of epoches to train 10000 transfer functions tansig, purelin training function trainlm fig. 6, schematic diagram of ann used for fzi model. nphi rhob phie sfl ild dt 1 fzi 2 3 4 5 : : 18 19 20 permeability prediction in one of iraqi carbonate reservoir using hydraulic flow units and neural networks 8 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net fig. 7, ann training performance for well 1 fig. 8, training, validation and testing the ann model for fzi values in well 1. permeability determination in uncored wells with ann model after calculating fzi in uncored well having effective porosity from well logs and using ann method, permeability can be determined for each hfu using equation 5. fig.(9) shows the results of calculated permeability and core permeability with depth. the correlation between core permeability versus the permeability values predicted from ann for the selected model was shown in fig.(10). good matching and good correlation were observed with correlation coefficient (r 2 ) equals 0.94 and average relative error (are) equals 1.04%. the predicted permeability profile for well 2 determined from ann model by assuming that well logged only then this well was used as a blind well for validation the model. dahlia abdulhadi alobaidi -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 9 fig. 9, permeability predicted from ann versus core permeability for well 2. fig. 10, permeability predicted from ann versus permeability measured from core well 2. permeability prediction in one of iraqi carbonate reservoir using hydraulic flow units and neural networks 10 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net conclusions 1flow zone indicator (fzi) is an effective and suitable parameter in correlating rock properties and for determining hydraulic flow units (hfus). these hfus represent the different rock types in the studied formation. 2using probability plot and log-log plot of rqi versus φz methods to determine the number of hfus and their boundaries is more reliable than histogram analysis. 3four hfus was obtained with high correlation coefficient r 2 for each hfu when relate the permeability that was derived from hfu with core porosity. 4good average relative error (are) equals 0.55% was obtained between core permeability and permeability calculated from hfu. 5good correlation coefficient r 2 = 0.96 was obtained between fzi derived from ann and fzi that was calculated from hfu which is an indication for accuracy of this method. 6artificial neural network model provides a good and accurate results for predicting permeability in uncored well with r 2 =0.94 and are= 1.04%. 7permeability profile predicted by ann model using well log data and hfus agree well with core permeability which clarify the applicability of this method. nomenclature ann: artificial neural network are: average relative error dt: sonic transient time, µsec/ft fzi: flow zone indicator, µm hfu: hydraulic flow unit hfus: hydraulic flow units ild: deep lateral log, ωm nphi: neutron log derived porosity, fraction phie: effective porosity, fraction rhob: density log, gm/cc rqi: reservoir quality index, µm sfl: spherically focused log, ωm symbols k: permeability, md n: number of variables r 2 : correlation coefficient øz : normalized porosity, fraction øe: effective porosity, fraction ø: porosity, fraction : any log value : normalized log references 1mehdi bagheripour haghighi and mehdi shabaninejad, 2011, a permeability predictive model based on hydraulic flow unit for one of iranian carbonate tight gas reservoir , spe middle east unconventional gas conference and exhibition held in muscat, oman ,january-february 2011. 2jude o. amaefule, mehmet altunbay and djebbar tiab, 1993, enhanced reservoir description: using core and log data to identify hydraulic flow units and predict permeability in uncored intervals/wells, paper spe 26436 spe annual technical conference and exhibition held in houston, texas, october 1993. 3tiab, d. advances in petrophysics, vol. 1-flow units. lecture notes manual, university of oklahoma, 2000 4mohamed s. el sharawy, 2013, petrophysical characteristics of the nubia sandstone along the b – trend, southern gulf of suez, egypt, based on the hydraulic flow units concept, journal of applied sciences research, 9(7): 4271-4287, 2013. 5taslimi m., kazemzadeh e. and kamali m.r." determining rock mass permeability in a carbonate reservoir, southern iran using dahlia abdulhadi alobaidi -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 11 hydraulic flow units and intelligent systems" , tehran, iran, wseas international conference on geology and seismology (ges '08), cambridge, uk, february 23-25, 2008. 6adnan a. abed, 2014, hydraulic flow units and permeability prediction in a carbonate reservoir, southern iraq from well log data using non-parametric correlation, international journal of enhanced research in science technology & engineering, issn: 2319-7463,vol. 3 issue 1, january-2014, pp: (480486). 7tohid nejad ghaffar borhani and seyed hossein emadi, 2011, application of hydraulic flow units and intelligent systems for permeability prediction in a carbonate reservoir, the 3rd (2011) cutse international conference, miri, sarawak, malaysia, 8-9 november, 2011. 8al-ajmi a.fahad, holditch a. stephen, 2000, permeability estimation using hydraulic flow units in a central arabia reservoir ,spe 63254, spe annual technical conference and exhibition held in dallas, texas, 1–4 october 2000. 9abdideh, mohammad, 2012, estimation of permeability using artificial neural networks and regression analysis in an iran oil field, international journal of the physical sciences vol. 7(34), pp. 5308-5313, 6 september, 2012. 10c.i. uguru, u.o. onyeagoro, j. lin, j. okkerman and i.o. sikiru, 2005, permeability prediction using genetic unit averages of flow zone indicators (fzis) and neural networks, spe 98828, 29th annual spe international technicalm conference and exhibition in abuja, nigeria, august 1-3, 2005. 11bishnu kumar & mahendra kishore, 2006, electrofacies classification – a critical approach, 6th international conference & exposition on petroleum geophysics , kolkata 2006. 12mohaghegh, s., ameri, s., and aminian, k. , 1996, a methodological approach for reservoir heterogeneity characterization using artificial neural networks, jornal of petroleum science and engineering, 16, pp.263-274, 1996. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.21 no.3 (september 2020) 19 – 27 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: khalid h.r. algharrawi , email: khalid.hussein@coeng.uobaghdad.edu.iq, name: mani subramanian, email: mani-subramanian@uiowa.edu ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. production of 7-methylxanthine from theobromine by metabolically engineered e. coli khalid h.r. algharrawi a,b and mani subramanian b a department of chemical engineering, university of baghdad, baghdad, iraq b department of chemical and biochemical engineering, the university of iowa, iowa city, ia 52242, usa abstract in this work, a novel biocatalytic process for the production of 7-methylxanthines from theobromine, an economic feedstock has been developed. bench scale production of 7-methlxanthine has been demonstrated. the biocatalytic process used in this work operates at 30 o c and atmospheric pressure, and is environmentally friendly. the biocatalyst was e. coli bl21(de3) engineered with ndmb/d genes combinations. these modifications enabled specific n7demethylation of theobromine to 7-methylxanthine. this production process consists of uniform fermentation conditions with a specific metabolically engineered strain, uniform induction of specific enzymes for 7-methylxanthine production, uniform recovery and preparation of biocatalyst for reaction and uniform recovery of pure 7-methylxanthine. many e. coli bl21(de3) strains metabolically engineered with single and/or multiple ndmb/d genes were tested for catalytic activity, and the best strains which had the higher activity were chosen to carry out the n-demethylation reaction of theobromine. strain pbd2ddb had the highest activity for the production of 7-methylxanthine from theobromine. that strain was used to find the optimum amount of cells required to achieve complete conversion of theobromine to 7-methylxanthine within two hours. it was found that the optimum concentration of pbd2ddb strain to achieve 100% conversion of 0.5 mm theobromine to 7-methylxanthine was 5 mg/ml. the cell growth of pbd2ddb strain was studied using two different growth media, (luria-bertani broth and super broth). super broth was found to be the best medium to produce the highest amount of cell paste (1.5 g). subsequently, the process was scaled up in which 2 l reaction volume was used to produce 7-methylxanthine (100% conversion) from 0.5 mm theobromine catalyzed by pbd2ddb strain. the reactions was carried out at 30 o c and 250 rpm shaker speed, and the reaction medium was 50 mm potassium phosphate buffer (ph=7). 7-methylxanthines was separated by preparative chromatography with high recovery, and the product solution was collected, purified by drying at 120-140 o c for 4 hours and, recovered (127 mg). purity of the isolated 7methylxanthine was comparable to authentic standards with no contaminant peaks, as observed by hplc, lc-ms, and nmr. keywords: 7-methylxanthine, theobromine, biocatalyst, e. coli, chromatographic separations received on 28/08/2020, accepted on 15/09/2020, published on 30/09/2020 https://doi.org/10.31699/ijcpe.2020.3.3 1introduction fig. 1. molecular structure of 7-methylxanthine 7-methylxanthine (7mx) is one of caffeine derivatives. it, in addition to other methylated xanthines, belongs to group of compounds known as purine alkaloids. methylxanthines are natural and synthetic compounds found in many foods, drinks, pharmaceuticals, and cosmetics [1, 2]. 7-methylxanthine (7mx), which has a methyl group attached to n7 of the xanthine ring (figure 1), has been proven to have a therapeutic effect on the development of form-deprivation myopia in pigmented rabbits [3]. trier et. al., studied the biochemical and ultrastructural changes in rabbit sclera after treatment with 7-mx [4]. similar study was also conducted on guinea pigs [5]. in another study, trier et. al., found that 7-methylxanthine reduces eye elongation and myopia progression in childhood myopia [6]. aside from caffeine, production of many methylxanthines is currently performed by chemical synthesis [7, 8]. 7-methylxanthine is currently produced only as ‘retail sample’ by chemical synthesis. however, no detailed information is available about the exact procedure used in the synthesis. chemical synthesis of 7mx might follow traube synthesis [7] or purine synthesis by fischer [9]. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:khalid.hussein@coeng.uobaghdad.edu.iq mailto:mani-subramanian@uiowa.edu http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2020.3.3 k. h.r. algharrawi and m. subramanian / iraqi journal of chemical and petroleum engineering 21,3 (2020) 19 27 20 chemical synthesis of 7mx, as the other methylxanthine, utilizes many chemicals, multiple reactions, and different reaction conditions, making it complicated, environmentally dissatisfactory, and expensive. additionally, there is no recorded research on the biocatalytic production of 7mx using any kind of bacterium. due to the high price of 7mx, there was no recorded market-size for 7mx; however, developing a new economical method for the production of 7mx has a potential for making this fine chemical. recently we developed a common bioprocess for the production of 3methylxanthine from theophylline [10] and theobromine from caffeine [11]. this work aims to use e. coli engineered with ndmb and ndmd genes to directly produce 7-methylxanthine from theobromine in one single reaction (figure 2). these genes were found in pseudomonas putida cbb5 that was able to degrade caffeine and its derivatives [12]. the n3demethylation reaction (which removes the methyl group on attached to the nitrogen atom at location 3 on the xanthine ring) is catalyzed by the enzyme ndmb. this enzyme is a rieske [2fe-2s] non-heme iron monooxygenase that requires a partner reductase, ndmd, to transfer electrons from nadh. the reaction requires one molecule of o2 per methyl group removed, resulting in the production of formaldehyde and water [10]. this work is the first report on the biocatalytic production of 7-methylxanthine from theobromine by metabolically engineered e. coli that includes separation and purification of the product. the n-demethylases genes ndmb and ndmd were introduced into e. coli at different gene dosages, and the resultant strains were screened for 7-mx production. the optimum strain with the highest 7mx production was chosen for further study. the biocatalytic approach used here operates at ambient temperature and pressure and is environmentally friendly. fig. 2. schematic representation for the biocatalytic ndemethylation of theobromine to 7-methylxanthine by e. coli bl21(de3) genetically engineered with ndemethylation genes of pseudomonas putida cbb5 ndmb and ndmd 2materials and methods 2.1. chemicals and reagents theobromine and 7-methylxanthne were purchased from sigma-aldrich (st. louis, mo, usa). luriabertani lennox (lb) and difco select aps tm super broth (sb) dehydrated media were obtained from becton dickinson and company (sparks, md, usa). hplcgrade methanol (j.t. baker, phillipsberg, nj, usa) was used in all chromatographic studies. 2.2. strain construction e. coli bl21(de3) was used to construct all strains required as it was explained in a previous research [10, 14]. these metabolically engineered e. coli strains are shown in table 1. 2.3. cell growth and protein expression e. coli strains were grown in super broth (sb) or lauria broth (lb) medium with appropriate antibiotic at 37 o c with shaking speed at 250 rpm. concentrations of antibiotic used were 34, 30 and 100 µg/ml for chloramphenicol, kanamycin and ampicillin respectively. cell density was monitored by measuring the optical density at 600 nm (od600). upon reaching an od600 of ~ 0.5, ferric chloride (fecl3·6h2o) was added (0.02 mm final concentration) and temperature was lowered to 18 o c. when the od reached (0.8-1), iptg was added (0.2 mm final concentration) to induce expression of ndmb and ndmd. the iptg concentration of 0.2 mm was previously determined to give optimum protein expression [12]. cells were harvested after (14-16) hours of induction by centrifugation at 10,000 x g for 20 min at 4 o c and washed twice in 50 mm cold potassium phosphate (kpi) buffer (ph 7.5). pelleted cells (wet cells) were weighed and resuspended in 50 mm kpi buffer prior to activity assays. 2.4. reactions for 7mx production all reactions (unless mentioned otherwise) were carried out in 2 ml microcentrifuge tubes with 1 ml total reaction volume containing theobromine. a vwr® symphony™ incubating microplate shaker was used to carry out the reaction at 30 °c and 400 rpm. 100 µl samples were taken periodically for hplc analysis, and concentrations of theobromine and 7-methylxanthine were calculated using appropriate standards. reactions for product isolation were carried out in 1.96 l total volume with 5 mg/ml cells concentration and theobromine concentration of 0.5 mm. these large-scale reactions were carried out in an excella e24 incubator shaker (eppendorf, hamburg, germany) shaker at 30 °c and 250 rpm. after all theobromine was consumed, the post-reaction mixture was centrifuged at 10,000 x g to separate the supernatant (7mx) from the cells. k. h.r. algharrawi and m. subramanian / iraqi journal of chemical and petroleum engineering 21,3 (2020) 19 27 21 2.5. preparatory hplc methods and product isolation purification of 7mx was carried out with preparatoryscale hplc using a shimadzu lc-10ad hplc system equipped with a photodiode array detector. a hypersil bds c18 column of 21.2 mm diameter and 25 cm length was used as the stationary phase. methanol-water-acetic acid (5:95:0.5, vol/vol/vol) was used as the mobile phase with an optimized flow rate of 2.5 ml/min. the molecules resolved by the c18 column passed through the photodiode array detector, in which uvvisible absorption spectra were recorded. this hplc is equipped with two pumps, a and b. the isocratic method was developed to be programmed so that pump b provided the mobile phase and pump a injected 25 ml of post-reaction mixture in 10 minute periods. at the end of the preparative chromatography 750 ml 7mx solution was collected in a bottle. the solution was concentrated by vacuum drying using buchi rotovap r114. the bath temperature was 60-70 °c. finally, the concentrated solution was dried at ~140 o c for four hours to ensure removal all impurities. the left 7mx powder in the tray was collected, weighed and stored in a vial. 2.6. analytical procedures identification and quantification of 7mx as conducted on the same hplc system described above. a hypersil bds c18 column (4.6 by 125 mm) was used as the stationary phase. the same mobile phase was used with a flow rate of 0.5 ml/min. purity of 3mx was confirmed by high resolution lc-ms facility at the university of iowa, department of chemistry using a waters q-tof premier interfaced with an acquity uplc system. the nmr results were obtained from the nmr facility at the chemistry department of the university of iowa. the spectrum was recorded in dmso-d6 with a bruker drx 500 nmr spectrometer at 300 k. the chemical shifts were relative to dmso-d6 using the standard δ notation in parts per million. 3results and discussion 3.1. screening of 7-methylxanthine production from theobromine by metabolically engineered e. coli five metabolically engineered e. coli strains were tested for activity to produce 7-methylxanthine from theobromine. these are single plasmid strains, pbd, ddb and two plasmid strains, pbdddb, pbdddd, and pbdddb. table 1 shows the number and type of genes carried on each vector in each strain. these strains have been constructed to be incorporated with single or multiple copies of ndmb and ndmd on both pet-32a(+) and pacycduet-1 expression compatible vectors [2]. 7-mx screening of the above strains were carried out in 1 ml reactions at 30 o c and atmospheric pressure and started with initial theobromine concentration of 0.5 mm and 5 mg/ml wet cell. analysis for 7-mx after two hours of reaction showed that strains pbd and ddb consumed 62% and 64% of theobromine fig. 3, this relatively same conversion indicates that the activity of the two strains is similar when a single copy of each of ndmb and ndmd are carried by any of the two compatible vectors (pbd and ddb). therefore, three duet vectors carrying two ndmd genes (ddd), two ndmb genes (ddd), and one gene of each of ndmd and ndmb (ddb) were transformed into e. coli carrying pbd resulting in three more strains (pbdddd, pbddbb, and pbdddb). in this case, the effect of adding additional copies of ndmb and ndmd genes on the activity was observed fig. 3. each of the above three strains were tested for ndemethylation of theobromine to 7-methylxantine under the same previous reaction conditions. after two hours of the reaction time, pbddbb strain consumed 90% of theobromine while pbdddd completely consumed all the 0.5 mm theobromine present in the reaction. however, pbdddb strain was able to convert all theobromine (100% conversion) to 7mx within ninety minutes fig. 3. this means pbdddb strain, which has an approximate copy number of 50 for each of ndmb and ndmd has a higher activity than pbdddd strain which has an approximate copy number of 40 and 60 for ndmb and ndmd respectively. table 1. estimated copy number of ndma and ndmd genes in strains used in this study strain approximate gene copy number* ndmd:ndmb ratio ndmb ndmd pbd 40 40 1.0 pbdddb 50 50 1.0 pbddbb 60 40 0.67 pbdddd 40 60 1.5 ddb 10 10 1.0 *approximate gene copy number was estimated based on approximate copy number of the plasmid (40 for pbd, 10 for ddb, dbb, and ddd) and number of genes in each plasmid. this value was calculated as ci=nijpij, where c i = gene copy number, n ij = number of genes i on plasmid j, p j = copy number of plasmid j backbone, i = gene (ndmb or ndmd), and j = plasmid backbone (pet or pacycduet-1) k. h.r. algharrawi and m. subramanian / iraqi journal of chemical and petroleum engineering 21,3 (2020) 19 27 22 fig. 3. (a) consumption of theobromine and (b) formation of 7-methylxanthine by metabolically engineered e. coli resting cells (, strain pbd ; , strain ddb; , strain pbddbb; , pbdddd; , strain pbdddd) [ initial theobromine concentration 0.5 mm, wet cells weight 5 mg/ml, temperature 30 o c, microplate shaking 400 rpm] 3.2. complete conversion of theobromine to 7-mx by strain pbdddb strain pbdddb was used to study theobromine consumption during the course of the n-demethylation reaction and achieving complete conversion to 7-mx. three different wet cells concentrations were used (5, 10, and 15 mg wet cells/ml). during the two hours’ reaction time, it was observed that the activity was high during the first hour of the reaction. after that, a reduction in the activity was noticed. during the first hour of the reaction, conversion of 86%, 94%, and 100% of the 0.5 mm theobromine present initially was achieved by biocatalyst concentrations of 5,10, and 15 mg/ml respectively. the rate of the reaction, as expected, was the highest with 15 mg wet cells/ml. the rate of the n-demethylation reaction became slower after one hour with 5 and 10 mg/ml cells and hence it took 30 and 60 minutes respectively for theobromine to be completely consumed. the reaction times for complete conversion were 60, 90, and 120 minutes for wet cells concentrations of 15,10, and 5 mg/ml respectively. also, based on the corresponding concentrations of 7mx produced and the time required for complete conversion for each case, the cells activities (mmole 7mx/mg cells.min) were determined. fig. 4 depicts theobromine consumption and 7methylxanthine formation by the three different concentrations of pbdddb strain. the activity for 5, 10, and 15 mg/ml resting cells concentrations were 8.3*10 -7 , 5.6*10 -7 , and 5.6*10 -7 mmole 7mx / (mg wet cells.min) respectively table 2. therefore, the highest activity was achieved by a wet cells concentration of 5 mg/ml. this is because of the lower quantity of cells was used to produce 7mx by a complete conversion of tb within two hours. as a result, 5 mg resting cells/ml was used for further work. fig. 4. theobromine consumption and 7-methylxanthine formation by different concentrations of metabolically engineered e. coli pbdddb strain (, 5 mg/ml; , 10 mg/ml; , 15 mg/ml) [ initial theobromine concentration 0.5 mm, temperature 30 c, microplate shaking 400 rpm] table 2. cell activities at different cells concentrations (pbdddb strain) wet cell concentration (mg/ml) time (min) 7-methylxanthine (mmole/ml) cells activity (mmole 7mx/mg cells.min) * 107 5 120 0.0005 8.3 10 90 0.0005 5.6 15 60 0.0005 5.6 k. h.r. algharrawi and m. subramanian / iraqi journal of chemical and petroleum engineering 21,3 (2020) 19 27 23 3.3. cell growth and theobromine to 7-mx conversion in luria broth and super broth the growth media has an important role in cells growth since it provides the required nutrients the cells need to grow and maintain their activities. all previous reactions used to produce 7mx were using cells grown in luria broth (lb) medium. luria broth medium is considered one of the basic medium for cell growth. the purpose here is to use super broth (sb), a richer and more complex medium than luria broth, and compare the amount of cells harvested from each medium. in addition to that, activity for the cells grown in each medium was also determined. each media (100 ml) was inoculated with pbdddb strain and left to grow overnight (14-16 hr). during that period, the cells grew to an optical cell density (od600) of 5.75 and 11.61 in lb and sb respectively. after harvesting, 0.62 and 1.5 g wet cells were produced from lb and sb respectively. the wet cells produced from sb were about 2.5 times larger the amount of cells produced from lb. this is a significant increase of the amount of wet cells harvested because sb is a richer nutrient medium and there is not much difference in cost of the media. the activity of the cells harvested from each medium was also tested. fig. 5. theobromine consumption and 7-methylxanthine formation by coli pbdddb strain grown in lauria broth () and super broth () [initial theobromine concentration 0.5 mm, temperature 30 o c, microplate shaking 400 rpm] fig. 5 shows tb consumption and 7mx production by the cells grown in lb and sb. theobromine consumption and 7mx formation were a little higher by the cells grown in sb than those grown in lb. this may be due to ‘healther cells’ in the rich sb, thus, super broth medium (sb) was considered as the growth medium for further work. fig. 6 shows the n-demethylation reaction of 0.5 mm theobromine to 7-mx. the 1 ml reaction was catalyzed by 5 mg/ml strain pbdddb grown in super broth. the reaction conditions were 30 c and 400 rpm micro-plate shaker speed. these conditions were used for scale up of 7-mx production. fig. 6. theobromine consumption () and 7methylxanthine production () by 5 mg/ml e. coli pbdddb strain grown in super broth [initial theobromine concentration 0.5 mm, temperature 30 c, microplate shaking 400 rpm] 3.4. scale up cell growth and 7-methylxanthine production the purpose of scale-up was to produce 100 mg 7mx pure powder for validation of the technology at the bench scale. to produce this amount of 7mx from theobromine, cell growth had to be scaled-up first. then, based on the amount of cells harvested, the reaction mixture was also scaled-up to produce, separate and characterize the purity of 7-mx super broth (1000 ml) in 2.5 l flask was used to grow the strain pdbddb overnight (14-16 hr). when the cells were harvested the optical density were at 600 nm (od600) 9.26. the wet cells were stored at 4 oc until use. the amount of cells harvested was 9.8 g. for resting cell concentration of 5 mg/ml in the reaction mixture, the amount of cell harvested was adequate to carry out a reaction of 1.96 l. the reaction conditions were 0.5 mm theobromine concentration, 5 mg/ml resting cells, temperature 30 oc, and shaker speed of 250 rpm. after two hours of reaction, all theobromine was converted to 7-mx (100% conversion). k. h.r. algharrawi and m. subramanian / iraqi journal of chemical and petroleum engineering 21,3 (2020) 19 27 24 fig. 7 shows the hplc chromatograms at the beginning and end of reaction in which all theobromine presented initially was consumed in two hours. thus, 0.5 mm (83 mg/ml) 7mx was produced. accordingly, the theoretical amount of 7mx produced in the total reaction mixture was 163 mg. fig. 7. hplc chromatograms for the 1.96 reaction at (a) 0 hour and (b) 2 hours 3.5. separation and purification of biocatalytically produced 7-methylxanthine after removing the solids from the reaction mixture by centrifugation, the post reaction supernatant volume collected was 1.9 l. this supernatant was filtered using 0.2 µm filter to completely remove any microparticles. this was done to avoid any potential contamination in the hplc separation column. this 1.9 l of supernatant, which contained 7mx solution, was concentrated by evaporation under vacuum to 750 ml. after that, that amount of product solution was introduced to the chromatographic separation column to separate the product. 7mx eluted at a retention time of 104 minute as it is shown in fig. 8. 7mx solution was collected in a bottle after each injection and the total volume of 7mx solution collected was 750 ml. the pooled solution was dried at ~140 oc for four hours to ensure removal of methanol (b.p. 65 oc), water (b.p. 100 oc), and acetic acid (b.p. 118 oc). the resultant 7mx powder in the tray was collected, weighed (127 mg) and stored in a vial fig. 9. the total recovery of 7-methylxanthine after chromatographic separation and purification was 78% (127 mg/163 mg), and the overall yield of 7mx based on the amount of theobromine fed to the reaction (0.5 mm in 1.96 l reaction) was 0.72 mg 7mx / mg theobromine. the yield could be much higher with use of a larger prep scale column (and avoid repeated injections and pooling of the product). this is the first report describing in detail, the biological production and separation of 7mx from theobromine by e. coli. engineered with the n-demethylation genes. fig. 8. separation of 7-methylxanthine (7mx) by preparative chromatography retention time of 7mx is 102 minutes fig. 9. 127 mg biologically produced 7-methylxanthine powder from theobromine k. h.r. algharrawi and m. subramanian / iraqi journal of chemical and petroleum engineering 21,3 (2020) 19 27 25 4analytical characterization of-methylxanthine the purity of 7mx was initially confirmed by analytical hplc using appropriate authentic standards. the retention time of the biologically produced product fig. 10 and authentic standards were identical. the high resolution lc-ms spectrum of biologically produced and standard 7mx was identical fig. 11. lc/ms was recorded on esi positive mode; distinct m+1 ion peak at 168.0591 and 168.0575 m/z were observed in the biologically produced and standard 7-methylxanthine respectively. fig. 10. hplc chromatograms for 0.5 mm 7methylxanthine (7mx) (a) biologically produced in this work (b) standard from sigma aldrich fig. 11. lc-ms spectrum of 7-methylxanthine (7mx). (a) lc-ms of biologically produced and purified 7methylxanthine sample produced in this work. (b) lc-ms of 7-methylxanthine standard obtained from sigma aldrich. the 1 h nmr spectrum of biologically produced and standard 7-methyl xanthine also matched very well fig. 12. 1 h nmr was recorded on a bruker 500 mhz spectrophotomer using dmso-d6 as solvent. standard 7methylxantine showed presence of peaks at δ 11.46 (s, 1h) and 10.82 (s, 1h) corresponding to –nh proton, and peaks at δ 7.87 and 3.81 corresponding to –c=h (s, 1h) and –ch3 group (s, 3h). the biologically produced 7-methylxanthine also showed peaks at δ 11.46 (s, 1h) and 10.82 (s, 1h) corresponding to –nh proton, and peaks at δ 7.87 and 3.81 corresponding to –c=h (s, 1h) and –ch3 group (s, 3h). in conclusion, the biologically produced 7methylxanthine in this work was highly pure and similar to the authentic standard by all analytical comparisons. k. h.r. algharrawi and m. subramanian / iraqi journal of chemical and petroleum engineering 21,3 (2020) 19 27 26 fig. 12. nmr of 7-methylxanthine (7mx) (a) nmr of biologically produced and purified 7-methylxanthine produced in this work. (b) nmr of 7-methylxanthine standard obtained from sigma aldrich. 5conclusion in this research, a novel biocatalytic process for the production of 7-methylxanthines from theobromine, an economic feedstock has been developed. the biocatalytic process used in this work operates at 30 oc and atmospheric pressure, and is environmentally friendly. the biocatalyst was e. coli bl21(de3) engineered with ndmb/d genes combinations. bench scale production of 7-methlxanthines has been demonstrated, and 127 mg higly pure 7mx was produced. this is the first report for the biological production of 7-methylxanthine. references [1] anaya, a.l., r. cruz-ortega, and g.r. waller, metabolism and ecology of purine alkaloids. front biosci, 2006. 11: p. 2354-2370. [2] khalid h. r. algharrawi, ryan m. summers, sridhar gopishetty & mani subramanian. "direct conversion of theophylline to 3-methylxanthine by metabolically engineered e. coli." microbial cell factories 14, no. 1 (2015): 203. [3] nie, h.-h., et al., effects of 7-methylxanthine on formdeprivation myopia in pigmented rabbits. international journal of ophthalmology, 2012. 5(2): p. 133. [4] trier, k., et al., biochemical and ultrastructural changes in rabbit sclera after treatment with 7methylxanthine, theobromine, acetazolamide, orlornithine. british journal of ophthalmology, 1999. 83(12): p. 1370-1375. [5] cui, d., et al., effects of 7‐methylxanthine on the sclera in form deprivation myopia in guinea pigs. acta ophthalmologica, 2011. 89(4): p. 328-334. [6] trier, k., et al., systemic 7-methylxanthine in retarding axial eye growth and myopia progression: a 36-month pilot study. journal of ocular biology, diseases, and informatics, 2008. 1(2-4): p. 85-93. [7] traube, w., der synthetische aufbau der harnsäure, des xanthins, theobromins, theophyllins und caffeïns aus der cyanessigsäure. berichte der deutschen chemischen gesellschaft, 1900. 33(3): p. 3035-3056. [8] yoneda, f., et al., synthesis of xanthines by dehydrogenative cyclization of 6-amino-5benzylideneaminouracils with diethyl azodicarboxylate. chemical & pharmaceutical bulletin, 1978. 26(9): p. 2905-2910. [9] fischer, e., umwandlung des xanthins in theobromin und coffeïn, in untersuchungen aus verschiedenen gebieten. 1924, springer. p. 50-52. [10] algharrawi, k.h., r.m. summers, and m. subramanian, production of theobromine by ndemethylation of caffeine using metabolically engineered e. coli. biocatalysis and agricultural biotechnology, 2017. [11] summers, r.m., et al., novel, highly specific ndemethylases enable bacteria to live on caffeine and related purine alkaloids. journal of bacteriology, 2012. 194(8): p. 2041-2049. [12] summers, r.m., et al., genetic characterization of caffeine degradation by bacteria and its potential applications. microbial biotechnology, 2015. \ https://www.researchgate.net/profile/ana_luisa_anaya/publication/7062943_metabolism_and_ecology_of_purine_alkaloids/links/09e41506c65fe0b491000000.pdf https://www.researchgate.net/profile/ana_luisa_anaya/publication/7062943_metabolism_and_ecology_of_purine_alkaloids/links/09e41506c65fe0b491000000.pdf https://www.researchgate.net/profile/ana_luisa_anaya/publication/7062943_metabolism_and_ecology_of_purine_alkaloids/links/09e41506c65fe0b491000000.pdf https://link.springer.com/article/10.1186/s12934-015-0395-1 https://link.springer.com/article/10.1186/s12934-015-0395-1 https://link.springer.com/article/10.1186/s12934-015-0395-1 https://link.springer.com/article/10.1186/s12934-015-0395-1 https://link.springer.com/article/10.1186/s12934-015-0395-1 https://www.ncbi.nlm.nih.gov/pmc/articles/pmc3359024/ https://www.ncbi.nlm.nih.gov/pmc/articles/pmc3359024/ https://www.ncbi.nlm.nih.gov/pmc/articles/pmc3359024/ https://www.ncbi.nlm.nih.gov/pmc/articles/pmc3359024/ https://www.ncbi.nlm.nih.gov/pmc/articles/pmc3359024/ https://www.ncbi.nlm.nih.gov/pmc/articles/pmc3359024/ https://www.ncbi.nlm.nih.gov/pmc/articles/pmc3359024/ https://www.ncbi.nlm.nih.gov/pmc/articles/pmc3359024/ https://onlinelibrary.wiley.com/doi/full/10.1111/j.1755-3768.2009.01688.x https://onlinelibrary.wiley.com/doi/full/10.1111/j.1755-3768.2009.01688.x https://onlinelibrary.wiley.com/doi/full/10.1111/j.1755-3768.2009.01688.x file:///c:/users/zaid/downloads/trier2008_article_systemic7-methylxanthineinreta.pdf file:///c:/users/zaid/downloads/trier2008_article_systemic7-methylxanthineinreta.pdf file:///c:/users/zaid/downloads/trier2008_article_systemic7-methylxanthineinreta.pdf file:///c:/users/zaid/downloads/trier2008_article_systemic7-methylxanthineinreta.pdf https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/cber.19000330352 https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/cber.19000330352 https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/cber.19000330352 https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/cber.19000330352 https://www.jstage.jst.go.jp/article/cpb1958/26/9/26_9_2905/_article/-char/ja/ https://www.jstage.jst.go.jp/article/cpb1958/26/9/26_9_2905/_article/-char/ja/ https://www.jstage.jst.go.jp/article/cpb1958/26/9/26_9_2905/_article/-char/ja/ https://www.jstage.jst.go.jp/article/cpb1958/26/9/26_9_2905/_article/-char/ja/ https://www.jstage.jst.go.jp/article/cpb1958/26/9/26_9_2905/_article/-char/ja/ https://link.springer.com/chapter/10.1007/978-3-642-51364-0_9 https://link.springer.com/chapter/10.1007/978-3-642-51364-0_9 https://link.springer.com/chapter/10.1007/978-3-642-51364-0_9 https://www.sciencedirect.com/science/article/abs/pii/s1878818116304765 https://www.sciencedirect.com/science/article/abs/pii/s1878818116304765 https://www.sciencedirect.com/science/article/abs/pii/s1878818116304765 https://www.sciencedirect.com/science/article/abs/pii/s1878818116304765 https://www.sciencedirect.com/science/article/abs/pii/s1878818116304765 https://jb.asm.org/content/194/8/2041.short https://jb.asm.org/content/194/8/2041.short https://jb.asm.org/content/194/8/2041.short https://jb.asm.org/content/194/8/2041.short https://sfamjournals.onlinelibrary.wiley.com/doi/full/10.1111/1751-7915.12262 https://sfamjournals.onlinelibrary.wiley.com/doi/full/10.1111/1751-7915.12262 https://sfamjournals.onlinelibrary.wiley.com/doi/full/10.1111/1751-7915.12262 k. h.r. algharrawi and m. subramanian / iraqi journal of chemical and petroleum engineering 21,3 (2020) 19 27 27 مثيل زانثين من الثيوبرومين بواسطة بكتريا القولون المعدلة وراثيا-7انتاج 2و ماني سوبرامانيان 1الغراويخالد حسين رحيمة قسم الهندسة الكيمياوية , جامعة بغداد , بغداد , العراق1 قسم الهندسة الكيمياوية والبايوكيمياوية , جامعة ايوا , ايوا, الواليات المتحدة2 الخالصة مثيل زانثين من الثيوبرومين باستخدام بكتريا القولون -7تناولت هذه الدراسة تطويرعملية جديدية ألنتاج bl21(de3) ( المعدلة وراثيا بمورثاتndmb/d) كعامل مساعد للتفاعل. الظروف التي استخدمت في سالالت من العامل المساعد 5درجة مئوية عند الضغط الجوي. في البدء تم استخدام 30عملية االنتاج هي 5هي افضل عامل مساعد بتركيز ) e. coli bl21(de3) pbd2ddbوبينت النتائج ان الساللة mg/ml ( في زمن حوالي ساعتين. ايضا تم 100ل زانثين بنسبة تحول )مثي-7( النتاج اكبر كمية من% ( lauria brothو ) (super broth( هما ) mediaال ) دراسة نمو العامل المساعد في نوعين من . (g 1.5)( حيث وصلت كميتها الى super brothتنمو اكثر في ال ) pbd2ddbووجد ان ساللة البكتريا مثيب زانثين. 7ملغرام من ال 100لعامل المساعد في عملية اكبر لغرض انتاج اكثر من بعد ذلك تم استخدام ا محلول فوسفات mm 50من الثيوبرومين في وسط mm 0.5لتر من سائل التفاعل يحتوي 2استخدم سرعة اهتزاز الهزاز. rpm 250درجة حرارة و 30(. التفاعل تم عند ph=7البوتاسيوم ) مثيل زانثين( بواسطة -7مرور حوالي ساعتين علة التفاعل تم عزل السائل الذي يحتوي على الناتج ) بعد حيث تم الحصول على نسبة فصل عالية. preparative chromatographyالترشيح, ثم تم فصله بواسطة ساعات. في النهاية تم 4لمدة oc 140-120بغد ذلك تم فصل وتنقية الناتج بالتجفيف عند درجة حرارة و lc-msو hplcمثيل زانثين عالي النقاوة كما اثبتته فحوص ال -7ملغرام من 127الحصول على nmr. الفصل الكروماتوغرافي مثيل زانثين , فيوبرومين , عامل مساعد , بكتريا القولون ,عمليات-7الكلمات الدالة: available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.22 no.4 (december 2021) 11 – 17 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: haider abbas, email: haider_abbas3000@yahoo.com, name: ammar s. abbas, email: ammarabbas@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. adsorption of flagyl on prepared ash from rice husk haider abbas and ammar s. abbas chemical engineering department, college of engineering university of baghdad, baghdad, iraq. abstract in recent years, it has been evident that searching for alternative methods with low-price and eco-friendly features that produce high-quality adsorbents is in high demand. in the present work, rice husk from iraqi rice named (amber) had been used as the primary source to produce rice husk ash (rha) for the removal of the antibiotic metronidazole (flagyl) from water. after good drying of rice husk, rha was obtained at 600 °c using an electric oven. rha has been investigated using x-ray diffraction (xrd), porosity, and surface area. the adsorption data of the experimental work were optimized to assess langmuir and freundlich's constants. the thermodynamic parameters is likely a change in (gipp’s energy (δg°), enthalpy (δh°), and entropy (δs°)). the impacts of increasing temperature on adsorption capacity were investigated using variant temperatures (25, 30, 45,65), and the results revealed that the dynamic adsorption data could be represented by the pseudo-second-order kinetics model. the observed values for the heat of adsorption as well as the free energy were revealed that the adsorption process of flagyl on rha favors high temperatures. keywords: amber rice, flagyl, rice husk, adsorption received on 08/12/2021, accepted on 29/12/2021, published on 30/12/2021 https://doi.org/10.31699/ijcpe.2021.4.2 1introduction data obtained from recent studies have recognized that drug manufacturing discharges and hospital effluents into the environment bypass the toxic concentrations [1, 2]. numerous methods have been attempted to specify the types of active pharmaceutical ingredients (apis) that constitute the highest levels of environmental hazards [3, 4]. one of the essential medications with daily uses during hospitalization is antibiotics [5]. studies have shown that the release of antibiotics into the waterier ambiance could contribute to the origination of bacteria with antibiotic-resistant genes [6, 7]. metronidazole is a well-known antibiotic related to the metronidazole class, used to treat infections caused by anaerobic bacteria, and protozoa are among the highest use antibiotics [8]. metronidazole is accused of resulting in phytotoxicity [9, 10]. recently, several methods have been applied to aid in removing or at least minimizing the hazardous effects of such drugs using more economical materials [11, 12]. rha has gained noticeable attention due to its effectiveness and being economically acceptable. [13, 14] as a byproduct, rha has plentiful uses, such as reinforcing materials, fertilizers, fillers, covering and protecting materials, building material constituents, and as a source of silica owing to its high silica content after combustion (approximately 95% silica), as shown in table 1 [15]. table 1. uses of rha [15] the form commercial uses as ash fertilizer, filler, oil absorbent, covering agent in steel production, adsorbent as a source of silica refractory, cement production as silica chemicals soap, catalysts, silicon, semi-conductor, etc the thermal yield of rice husk combustion activated carbon, xylose the draining and rivers of vast quantities of impurities wastes (such as plastics, textile, pharmaceutical industries, etc.) into water has been considered the most critical worldwide problem [16]. globally, adsorption is one of the different methods experimented with to eliminate medical from wastewater and found to be very effective in terms of simplicity and economically low cost [17, 18]. adsorption is physicochemical processing in which variant types of molecules will depose on a surface [19, 20]. variant carbons have been obtained from different agricultural and wood wastes, which are widely available and considered environmentally friendly [21-28]. the current study was designed to inspect the preparation and characterization of rha from amber rice waste in addition to evaluating the ability of rha to adsorbed flagyl (metronidazole) from wastewater. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:haider_abbas3000@yahoo.com mailto:ammarabbas@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2021.4.2 h. a. and a. s. abbas / iraqi journal of chemical and petroleum engineering 22,4 (2021) 11 17 12 2experimental work 2.1. preparation and investigation of rha characterization the raw materials, the iraqi rice husk named (amber) at the beginning were washed several times with (deionized water) distilled water for removing dust, dirt, and other impurities then it all have been removed, but before that, it will be weighted and then drying process had been applied for 6 hours using the dryer at 100 °c to ensure that any humidity has been removed, dried rice husk was separated to take the weight and placed in diluted acid for 24 hours, after that the drying process was returned to ensure that any humidity has been removed, the resultant had been applied in a furnace at 600 °c for 6 hours to convert a solid rha. the rha properties have been checked by xrd, porosity, and bet surface area. the prepared rha was investigated using xrd in the ministry of industry, and minerals, the chemical and petrochemical center. crystallinity was examined while the pores volume of the rha, as well as the surface area, were determined using brunauer–emmett–teller (bet) method. the later method was performed using surface area apparatus analyzer-q surf series. 2.2. adsorption of flagyl a 500 mg/l (ppm) stock solution of flagyl was made by dissolving the calculated quantities of flagyl in deionized water. the study was established using 500 ml conical flasks by mixing a previously weighed amount of flagyl with the 1-gram of rha. an agitation has been applied to the solution at 300 rpm with a stirrer at a prespecified temperature for every run (25, 30, 40, and 50 °c). after shaking, the mixtures were centrifuged and filtrated. the time interval for reading was (5, 15,25,35,45,60,75,90, and 420 minutes). the flagyl concentration was measured at 336 nm as the absorbance wavelength by uv-vis apparatus recording spectrophotometer (uv-160a) presented in the chemical engineering department, college of engineering, university of baghdad. the adsorption capacity, which refers to the quantity of the adsorbed flagyl per weight of the adsorbent (rice ash) at equilibrium (qe, mg/g) was computed using equation (1). the flagyl removal trend was determined by equation (2).  e o e v q c c m    (1) flagyl removal, %= 100%o t o c c c   (2) where 𝑞𝑒 refers to the capacity of equilibrium adsorption of the adsorbent (in mg/g) while 𝐶𝑜 , 𝐶𝑡and 𝐶𝑒 in (mg/l) represent the initial, at any time, and the final concentrations of flagyl, respectively. v represents the volume of adsorption, which has the unit of l, and m that has the unit (g) refers to the weight of rha consumed. 2.3. kinetics models and adsorption isotherms the concept of adsorption isotherms demonstrates the tendency of interaction that occurs between the adsorbates and adsorbents. the currently used method of twoparameter isotherms was chosen to illustrate the precise amount of the adsorbed flagyl on the prepared rha. the adsorption models that were used were langmuir (equation (3)) [29] and freundlich (equation (4)) [30]. max 1 l e e l e q k c q k c   (3) 1 n e f e q k c (4) where 𝑞𝑒 refers to the adsorption capacity (in mg) of the adsorbate per each gram of adsorbent, 𝐶𝑒 is the concentration of flagyl at equilibrium in (mg/l), 𝑞𝑚𝑎𝑥 is the maximum capacity of adsorption to produce a superficial monolayer on the rice ash surface in (mg/g). 𝐾𝐿 presents langmuir coefficient associated with the degree of affinity between the adsorbate and adsorbent in (l/mg), while 𝐾𝐹 refers to the freundlich coefficient, and n refers to the total numbers of multilayers produced. two models [31], which are pseudo-first-order (equation 5), and pseudo-second-order (equation 6) were performed to show the variation in the capacity of adsorption with time.   1e t eln q q lnq k t   (1) 2 1 t e e t t q k q q   (2) where 𝑞𝑒 , and 𝑞𝑡 (in mg/g) refer to the capacity of adsorption at equilibrium and at any time (t), respectively. the adsorption rates constant 𝑘1 in (1/min) is used for pseudo-first-order, while the adsorption rate constants 𝑘2 in (g/mg. min), and 𝑘3 in (mg/(g.min 0.5 )) are used for pseudo-second order reaction. by maximizing the correlation coefficient (r 2 ), all the observational values of the isothermal and kinetics models were calculated numerically. (equation (7)) [32].       2 exp 2 1 2 2 exp exp 1 1 n cal i n n cal cal i i q q r q q q q            (3) in equation (7), 𝑞𝑒𝑥𝑝 and 𝑞𝑐𝑎𝑙 (in mg/g) refer to the experimental value and computed value (from the model) of the adsorption capacity, respectively. (i) refers to the current number of the experiment, and n refers to the overall numbers of the performed experiments. h. a. and a. s. abbas / iraqi journal of chemical and petroleum engineering 22,4 (2021) 11 17 13 2.4. characterization of thermodynamic analysis the thermodynamic trend of flagyl adsorption on the prepared rice husk surface was inspected to calculate thermodynamic parameters during adsorption. the alterations in gibbs free energy (∆𝐺°enthalpy (∆𝐻°) and entropy (∆𝑆°) had been computed by conventional thermodynamic equations (equation (8) and equation (9)) using the distribution coefficient (k𝑑) for determination of adsorption of flagyl on the surface of the rha (equation 10) [23, 33]. g h t s     (4)  ln dg rt k   (5) d k = e e q m c v       (6) in equation (9), r implies the gas constant (which is equal to 8.314 j/mol k), while t (k) refers to the absolute temperature used during the process of adsorption. 3results and discussion 3.1. characterization of rha analysis of the rha using x-ray diffractograms was presented in figure 1. the main peak at angles (2θ = 22° refers mainly to silica. however, the measured surface area and pore volume were equal to 148.53 m 2 /g and 0.2540 cm 3 /g, respectively. fig. 1. x-ray diffractogram model of the rha 3.2. the pattern of adsorption of flagyl on the rha a. equilibrium and adsorption isotherms the flagyl removal versus different initial concentrations of flagyl was represented in table 2. the flagyl (organics) removal increased with the decreasing of initial concentration. the increase in the removal values of flagyl molecules accompanied by the decrease in the initial concentration could be explained by the presence of competition of flagyl molecules on the most predominant sites of adsorption, which are the pores and the surface of the prepared adsorbents, and this competition decreases when lower flagyl concentrations were used [34]. table 2. flagyl removal versus initial concentrations co, ppm 503 389 308 207 72 51 removal% 57.85 60.67 66.23 69.57 73.61 76.47 fig. 2 showed the equilibrium adsorption capacity of rha increased from 39 to 291 mg/g with an increment in the equilibrium concentrations from 12 ppm (obtained at a lower initial concentration of flagyl) to 212 ppm. these data were used to solve and obtain via the nonlinear regression analysis, the langmuir and freundlich isotherms, and solution results were summarized in table 3. the resultant data revealed that the manufactured rice husk possesses a maximum capacity of adsorption with the amount of flagyl equal to 588.24 mg for each one gram of the produced rice husk. the elevated value of r 2, which was (0.9940), indicated that the langmuir model best suits the data of the adsorption equilibrium and the flagyl adsorbed on the rh surface as a monolayer. fig. 2. flagyl concentration equilibrium effect on the equilibrium capacity of the prepared rice husk table 3. adsorption models constants and the correlation coefficients (r 2 ) for the flagyl removal pattern on the papered rice husk isotherm model parameters value of parameter r 2 langmuir 𝑞𝑚𝑎𝑥, mg/g 588.24 0.9940 𝐾𝐿, l/mg 0.0060 freundlich 𝐾𝐹, mg 1-n l n /g 1.59 0.9577 n, 8.88 h. a. and a. s. abbas / iraqi journal of chemical and petroleum engineering 22,4 (2021) 11 17 14 as shown in figure 3, the removal of flagyl was raised obviously in the first hour of the experiment because the pores of the prepared rice husk were empty at the beginning. the significant difference in concentrations led to the rapid transfer of flagyl molecules from liquid bulk to the rice husk surface. in the second period (up to 180 minutes), the removal increased gradually because of the decreasing of flagyl concentration that caused a decrease in the transfer driving force, and the pores were filled with more flagyl that adsorbed on the rha surface, and then competition increasing between flagyl molecules to find an empty site. fig. 3. relationship between time and the pattern of flagyl removal via adsorption process on rha the kinetic analysis obtained from the adsorption of the flagyl on the rice husk was summarized in table 4. the resulted values of the r 2 indicated that the pseudosecond-order model (equation 6) was well expressed in the data of the experiment. the r 2 data for the pseudo-second-order model ranged from 0.9533 to 0.9658, which demonstrated a significant and precise description of the resultant data of the experiment with the pseudo-second-order model. table 4. adsorption constants and correlation coefficients (r 2 ) for the reduction of cod on the papered rice husk adsorption kinetic model model rate constant model parameter value at temperature 25 °c 30 °c 40 °c 50 °c pseudo-first order 𝑘1, (1/min) 0.0205 0.0168 0.0143 0.0122 𝑞𝑒, (mg/g) 208.0961016 193.0791098 191.464038 185.6754023 r² 0.9397 0.8999 0.878 0.8344 pseudosecond order 𝑘2, (g/mg.min) 0.025431426 0.02417962 0.022988506 0.023144453 𝑞𝑒, (mg/g) 357.1428571 357.1428571 357.1428571 344.8275862 r² 0.9658 0.9614 0.9596 0.9533 table 5 showed that the thermodynamic process of flagyl removal had a positive value of ∆h (equal 1827.3 j/mol) which means that the flagyl adsorption increases as the temperature of the experiment decrease. additionally, the increasing values of ∆g with the temperatures imply that the adsorption favored a reduction in temperatures. furthermore, the resultant observations of negative values ∆g with the positive value of ∆s (which is equal to 8.70 j/ mol k) refer to the spontaneous adsorption of flagyl molecules on the prepared rha. table 5. adsorption thermodynamic parameters and correlation coefficients (r 2 ) for the reduction of cod on the papered rice husk temperature, °c (k) kd thermodynamic parameters r 2 ∆𝐺, j/mol ∆𝐻, j/mol ∆𝑆, j/mol k 25 1.358 -759.1 1827.3 8.70 0.9944 30 1.381 -813.1 40 1.415 -904.2 50 1.439 -977.4 4conclusion in the recent few decades, there has been a big deal of attention to produce adsorbents characterized by high adsorption capacity while minimizing the cost of the production and impurities associated with the production process. the present work inspected the efficiency of rha as an adsorbent to remove metronidazole (flagyl) molecules. the current study results revealed that the percent of removal of flagyl was inversely proportional to their initial concentrations, i.e., the percent of removal of flagyl increased as the initial concentration was decreased. additionally, rha equilibrium adsorption capacity was directly proportional to the equilibrium concentration. moreover, the removal of flagyl molecules was significantly rapid in the first hour of the adsorption process. the adsorption process occurred due to the emptiness of the rha surface, leading to a less competition effect than the second period of the process when the concentration of flagyl was gradually increased. furthermore, the thermodynamic analysis results indicated the inverse relationship between the temperature of the process and the adsorption capacity, with the positive value of ∆h (1827.3 j/mol). references [1] escher bi, baumgartner r, koller m, treyer k, lienert j, mcardell cs. environmental toxicology and risk assessment of pharmaceuticals from hospital wastewater. water research. 2011 jan 1;45(1):75-92. [2] larsson dj. pollution from drug manufacturing: review and perspectives. phil. trans. r. soc. b. 2014 nov 19;369(1656):20130571. [3] boxall a. b. new and emerging water pollutants arising from agriculture: 2012. [4] sorell tl. approaches to the development of human health toxicity values for active pharmaceutical ingredients in the environment. the aaps journal. 2016 jan 1;18(1):92-101. https://www.sciencedirect.com/science/article/abs/pii/s004313541000583x https://www.sciencedirect.com/science/article/abs/pii/s004313541000583x https://www.sciencedirect.com/science/article/abs/pii/s004313541000583x https://www.sciencedirect.com/science/article/abs/pii/s004313541000583x https://royalsocietypublishing.org/doi/full/10.1098/rstb.2013.0571 https://royalsocietypublishing.org/doi/full/10.1098/rstb.2013.0571 https://royalsocietypublishing.org/doi/full/10.1098/rstb.2013.0571 https://eprints.whiterose.ac.uk/75319/1/oecdreport.pdf https://eprints.whiterose.ac.uk/75319/1/oecdreport.pdf https://link.springer.com/article/10.1208/s12248-015-9818-5 https://link.springer.com/article/10.1208/s12248-015-9818-5 https://link.springer.com/article/10.1208/s12248-015-9818-5 https://link.springer.com/article/10.1208/s12248-015-9818-5 h. a. and a. s. abbas / iraqi journal of chemical and petroleum engineering 22,4 (2021) 11 17 15 [5] lien lt, hoa nq, chuc nt, et al. antibiotics in wastewater of a rural and an urban hospital before and after wastewater treatment, and the relationship with antibiotic use-a one year study from vietnam. int j environ res public health. 2016;13(6):588. published 2016 jun 14. doi:10.3390/ijerph13060588. [6] shakti rath, bydute kumar dispersal of antibiotic resistant bacteria into aquatic environment an overview. imedpub journals. 2018. published:february 07, 2018. vol.1 no.1:2. [7] rodriguez-mozaz s, chamorro s, marti e, huerta b, gros m, sànchez-melsió a, borrego cm, barceló d, balcázar jl. occurrence of antibiotics and antibiotic resistance genes in hospital and urban wastewaters and their impact on the receiving river. water research. 2015 feb 1;69:234-42. [8] metronidazole: medlineplus drug information. available at https://medlineplus.gov › drugs, herbs and supplements [9] pharmaceutical wastewater effluent-source of contaminants of emerging concern: phytotoxicity of metronidazole to soybean (glycine max). toxics. 2017;5(2):10. published 2017 apr 2. doi:10.3390/toxics5020010. [10] metronidazole:topics by science.gov retrieved from https://www.science.gov/topicpages/m/metronidazole [11] shraim a, diab a, alsuhaimi a, niazy e, metwally m, amad m, sioud s, dawoud a. analysis of some pharmaceuticals in municipal wastewater of almadinah almunawarah. arabian journal of chemistry. 2017 feb 1;10:s719-29. [12] nasseh i, khodadadi m, khosravi r, beirami a, nasseh n. metronidazole removal methods from aquatic media: a systematic review. annals of military and health sciences research. 2016;14(4). [13] ahmaruzzaman m, gupta vk. rice husk and its ash as low-cost adsorbents in water and wastewater treatment. industrial & engineering chemistry research. 2011 nov 23;50(24):13589-613. [14] foo ky, hameed bh. utilization of rice husk ash as novel adsorbent: a judicious recycling of the colloidal agricultural waste. advances in colloid and interface science. 2009 nov 30;152(1-2):39-47. [15] production of high quality rice husk ash greenwich academic literature archive (gala). retrieved from http://gala.gre.ac.uk/12130 [16] mulugeta m, lelisa b. removal of methylene blue (mb) dye from aqueous solution by bioadsorption onto untreated parthenium hystrophorous weed. modern chemistry & applications. 2014 dec 30. [17] s. mondal, “methods of dye removal from dye house effluent—an overview,” environmental engineering science, vol. 25, no. 3, pp. 383–396, 2008. [18] mohammed ma, shitu a, ibrahim a. removal of methylene blue using low cost adsorbent: a review. research journal of chemical sciences issn. 2014;2231:606x. [19] ghorai s, sarkar a, raoufi m, panda ab, schönherr h, pal s. enhanced removal of methylene blue and methyl violet dyes from aqueous solution using a nanocomposite of hydrolyzed polyacrylamide grafted xanthan gum and incorporated nanosilica. acs applied materials & interfaces. 2014 mar 21;6(7):4766-77. [20] g. crini, “non-conventional low-cost adsorbents for dye removal: a review,” bioresource technology, vol. 97, no. 9, pp. 1061–1085, 2006. [21] khamparia s, jaspal d, malviya a. optimization of adsorption process for removal of sulphonated di azo textile dye. green chemistry & technology letters. 2015 nov 19;1(01):61-6. [22] barno, suondos ka, and ammar s. abbas. "reduction of organics in dairy wastewater by adsorption on a prepared charcoal from iraqi sugarcane." in iop conference series: materials science and engineering, vol. 736, no. 2, p. 022096. iop publishing, 2020. [23] a. r. tehrani-bagha, h. nikkar, n. m. mahmoodi, m. markazi, and f. m. menger, “the sorption of cationic dyes onto kaolin: kinetic, isotherm and thermodynamic studies,” desalination, vol. 266, no. 1–3, pp. 274–280, 2011. [24] barno, suondos ka, haider j. mohamed, siham m. saeed, mohammed j. al-ani, and ammar s. abbas. "prepared 13x zeolite as a promising adsorbent for the removal of brilliant blue dye from wastewater." iraqi journal of chemical and petroleum engineering 22, no. 2 (2021): 1-6. [25] a. s. abbas and s. a. hussien, “equilibrium, kinetic and thermodynamic study of aniline adsorption over prepared zsm-5 zeolite,” iraqi j. chem. pet. eng., vol. 18, no. 1, pp. 47–56, 2017. [26] r. k. abid and a. s. abbas, “adsorption of organic pollutants from real refinery wastewater on prepared cross-linked starch by epichlorohydrin,” data br., vol. 19, pp. 1318–1326, 2018, doi: 10.1016/j.dib.2018.05.060. [27] f. k. al-jubory, i. m. mujtaba, and a. s. abbas, “preparation and characterization of biodegradable crosslinked starch ester as adsorbent,” in 2nd international conference on materials engineering & science (iconmeas 2019), 2020, pp. 20165–20169, doi: https://doi.org/10.1063/5.0000170. [28] al-jubory, f. k., i. m. mujtaba, and a. s. abbas. "removal of ciprofloxacin from aqueous solution using prepared biodegradable potato crosslinked starch ester." in iop conference series: materials science and engineering, vol. 1076, no. 1, p. 012031. iop publishing, 2021. [29] i. langmuir, “the constitution and fundamental properties of solids and liquids. part i. solids.,” j. am. chem. soc., vol. 38, no. 11, pp. 2221–2295, nov. 1916. [30] h. m. f. freundlich, “uber die adsorption in losungen,” zeitschrift fur phys. chemie-leipzig, vol. 57a, pp. 385–470, 1906. https://www.mdpi.com/1660-4601/13/6/588 https://www.mdpi.com/1660-4601/13/6/588 https://www.mdpi.com/1660-4601/13/6/588 https://www.mdpi.com/1660-4601/13/6/588 https://www.mdpi.com/1660-4601/13/6/588 https://www.mdpi.com/1660-4601/13/6/588 https://www.researchgate.net/profile/shakti_rath4/publication/329240218_dispersal_of_antibiotic_resistant_bacteria_into_aquatic_environment_-_an_overview/links/5bfe778992851c63caae572c/dispersal-of-antibiotic-resistant-bacteria-into-aquatic-environment-an-overview.pdf https://www.researchgate.net/profile/shakti_rath4/publication/329240218_dispersal_of_antibiotic_resistant_bacteria_into_aquatic_environment_-_an_overview/links/5bfe778992851c63caae572c/dispersal-of-antibiotic-resistant-bacteria-into-aquatic-environment-an-overview.pdf https://www.researchgate.net/profile/shakti_rath4/publication/329240218_dispersal_of_antibiotic_resistant_bacteria_into_aquatic_environment_-_an_overview/links/5bfe778992851c63caae572c/dispersal-of-antibiotic-resistant-bacteria-into-aquatic-environment-an-overview.pdf https://www.researchgate.net/profile/shakti_rath4/publication/329240218_dispersal_of_antibiotic_resistant_bacteria_into_aquatic_environment_-_an_overview/links/5bfe778992851c63caae572c/dispersal-of-antibiotic-resistant-bacteria-into-aquatic-environment-an-overview.pdf https://www.sciencedirect.com/science/article/abs/pii/s004313541400791x https://www.sciencedirect.com/science/article/abs/pii/s004313541400791x https://www.sciencedirect.com/science/article/abs/pii/s004313541400791x https://www.sciencedirect.com/science/article/abs/pii/s004313541400791x https://www.sciencedirect.com/science/article/abs/pii/s004313541400791x https://www.sciencedirect.com/science/article/abs/pii/s004313541400791x https://medlineplus.gov/ https://www.mdpi.com/2305-6304/5/2/10 https://www.mdpi.com/2305-6304/5/2/10 https://www.mdpi.com/2305-6304/5/2/10 https://www.mdpi.com/2305-6304/5/2/10 https://www.mdpi.com/2305-6304/5/2/10 https://www.science.gov/topicpages/m/metronidazole https://www.sciencedirect.com/science/article/pii/s1878535212002705 https://www.sciencedirect.com/science/article/pii/s1878535212002705 https://www.sciencedirect.com/science/article/pii/s1878535212002705 https://www.sciencedirect.com/science/article/pii/s1878535212002705 https://www.sciencedirect.com/science/article/pii/s1878535212002705 https://health.bums.ac.ir/dorsapax/filemanager/userfiles/sub_32/m333262.pdf https://health.bums.ac.ir/dorsapax/filemanager/userfiles/sub_32/m333262.pdf https://health.bums.ac.ir/dorsapax/filemanager/userfiles/sub_32/m333262.pdf https://health.bums.ac.ir/dorsapax/filemanager/userfiles/sub_32/m333262.pdf https://pubs.acs.org/doi/abs/10.1021/ie201477c https://pubs.acs.org/doi/abs/10.1021/ie201477c https://pubs.acs.org/doi/abs/10.1021/ie201477c https://pubs.acs.org/doi/abs/10.1021/ie201477c https://www.sciencedirect.com/science/article/abs/pii/s0001868609000906 https://www.sciencedirect.com/science/article/abs/pii/s0001868609000906 https://www.sciencedirect.com/science/article/abs/pii/s0001868609000906 https://www.sciencedirect.com/science/article/abs/pii/s0001868609000906 http://gala.gre.ac.uk/12130 https://www.researchgate.net/profile/million-habtegebrel/publication/325398169_removal_of_methylene_blue_mb_dye_from_aqueous_solution_by_bioadsorption_onto_untreated_parthenium_hystrophorous_weed/links/5b0bd4cc4585157f871b490e/removal-of-methylene-blue-mb-dye-from-aqueous-solution-by-bioadsorption-onto-untreated-parthenium-hystrophorous-weed.pdf https://www.researchgate.net/profile/million-habtegebrel/publication/325398169_removal_of_methylene_blue_mb_dye_from_aqueous_solution_by_bioadsorption_onto_untreated_parthenium_hystrophorous_weed/links/5b0bd4cc4585157f871b490e/removal-of-methylene-blue-mb-dye-from-aqueous-solution-by-bioadsorption-onto-untreated-parthenium-hystrophorous-weed.pdf https://www.researchgate.net/profile/million-habtegebrel/publication/325398169_removal_of_methylene_blue_mb_dye_from_aqueous_solution_by_bioadsorption_onto_untreated_parthenium_hystrophorous_weed/links/5b0bd4cc4585157f871b490e/removal-of-methylene-blue-mb-dye-from-aqueous-solution-by-bioadsorption-onto-untreated-parthenium-hystrophorous-weed.pdf https://www.researchgate.net/profile/million-habtegebrel/publication/325398169_removal_of_methylene_blue_mb_dye_from_aqueous_solution_by_bioadsorption_onto_untreated_parthenium_hystrophorous_weed/links/5b0bd4cc4585157f871b490e/removal-of-methylene-blue-mb-dye-from-aqueous-solution-by-bioadsorption-onto-untreated-parthenium-hystrophorous-weed.pdf https://www.liebertpub.com/doi/abs/10.1089/ees.2007.0049 https://www.liebertpub.com/doi/abs/10.1089/ees.2007.0049 https://www.liebertpub.com/doi/abs/10.1089/ees.2007.0049 https://www.liebertpub.com/doi/abs/10.1089/ees.2007.0049 https://www.researchgate.net/profile/abubakar-shitu-2/publication/285818165_removal_of_methylene_blue_using_low_cost_adsorbent_a_review/links/59198cd8aca2722d7cfe151b/removal-of-methylene-blue-using-low-cost-adsorbent-a-review.pdf https://www.researchgate.net/profile/abubakar-shitu-2/publication/285818165_removal_of_methylene_blue_using_low_cost_adsorbent_a_review/links/59198cd8aca2722d7cfe151b/removal-of-methylene-blue-using-low-cost-adsorbent-a-review.pdf https://www.researchgate.net/profile/abubakar-shitu-2/publication/285818165_removal_of_methylene_blue_using_low_cost_adsorbent_a_review/links/59198cd8aca2722d7cfe151b/removal-of-methylene-blue-using-low-cost-adsorbent-a-review.pdf https://www.researchgate.net/profile/abubakar-shitu-2/publication/285818165_removal_of_methylene_blue_using_low_cost_adsorbent_a_review/links/59198cd8aca2722d7cfe151b/removal-of-methylene-blue-using-low-cost-adsorbent-a-review.pdf https://pubs.acs.org/doi/abs/10.1021/am4055657 https://pubs.acs.org/doi/abs/10.1021/am4055657 https://pubs.acs.org/doi/abs/10.1021/am4055657 https://pubs.acs.org/doi/abs/10.1021/am4055657 https://pubs.acs.org/doi/abs/10.1021/am4055657 https://pubs.acs.org/doi/abs/10.1021/am4055657 https://pubs.acs.org/doi/abs/10.1021/am4055657 https://www.sciencedirect.com/science/article/abs/pii/s0960852405002452 https://www.sciencedirect.com/science/article/abs/pii/s0960852405002452 https://www.sciencedirect.com/science/article/abs/pii/s0960852405002452 https://core.ac.uk/download/pdf/268007184.pdf https://core.ac.uk/download/pdf/268007184.pdf https://core.ac.uk/download/pdf/268007184.pdf https://core.ac.uk/download/pdf/268007184.pdf https://iopscience.iop.org/article/10.1088/1757-899x/736/2/022096/meta https://iopscience.iop.org/article/10.1088/1757-899x/736/2/022096/meta https://iopscience.iop.org/article/10.1088/1757-899x/736/2/022096/meta https://iopscience.iop.org/article/10.1088/1757-899x/736/2/022096/meta https://iopscience.iop.org/article/10.1088/1757-899x/736/2/022096/meta https://iopscience.iop.org/article/10.1088/1757-899x/736/2/022096/meta https://www.sciencedirect.com/science/article/abs/pii/s0011916410006302 https://www.sciencedirect.com/science/article/abs/pii/s0011916410006302 https://www.sciencedirect.com/science/article/abs/pii/s0011916410006302 https://www.sciencedirect.com/science/article/abs/pii/s0011916410006302 https://www.sciencedirect.com/science/article/abs/pii/s0011916410006302 https://doi.org/10.31699/ijcpe.2021.2.1 https://doi.org/10.31699/ijcpe.2021.2.1 https://doi.org/10.31699/ijcpe.2021.2.1 https://doi.org/10.31699/ijcpe.2021.2.1 https://doi.org/10.31699/ijcpe.2021.2.1 https://doi.org/10.31699/ijcpe.2021.2.1 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/192 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/192 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/192 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/192 https://www.sciencedirect.com/science/article/pii/s2352340918305663 https://www.sciencedirect.com/science/article/pii/s2352340918305663 https://www.sciencedirect.com/science/article/pii/s2352340918305663 https://www.sciencedirect.com/science/article/pii/s2352340918305663 https://www.sciencedirect.com/science/article/pii/s2352340918305663 https://aip.scitation.org/doi/abs/10.1063/5.0000170 https://aip.scitation.org/doi/abs/10.1063/5.0000170 https://aip.scitation.org/doi/abs/10.1063/5.0000170 https://aip.scitation.org/doi/abs/10.1063/5.0000170 https://aip.scitation.org/doi/abs/10.1063/5.0000170 https://doi.org/10.1063/5.0000170 https://iopscience.iop.org/article/10.1088/1757-899x/1076/1/012031/meta https://iopscience.iop.org/article/10.1088/1757-899x/1076/1/012031/meta https://iopscience.iop.org/article/10.1088/1757-899x/1076/1/012031/meta https://iopscience.iop.org/article/10.1088/1757-899x/1076/1/012031/meta https://iopscience.iop.org/article/10.1088/1757-899x/1076/1/012031/meta https://iopscience.iop.org/article/10.1088/1757-899x/1076/1/012031/meta https://pubs.acs.org/doi/pdf/10.1021/ja02268a002 https://pubs.acs.org/doi/pdf/10.1021/ja02268a002 https://pubs.acs.org/doi/pdf/10.1021/ja02268a002 https://pubs.acs.org/doi/pdf/10.1021/ja02268a002 https://www.degruyter.com/document/doi/10.1515/zpch-1907-5723/html https://www.degruyter.com/document/doi/10.1515/zpch-1907-5723/html https://www.degruyter.com/document/doi/10.1515/zpch-1907-5723/html h. a. and a. s. abbas / iraqi journal of chemical and petroleum engineering 22,4 (2021) 11 17 16 [31] k. l. tan and b. h. hameed, “insight into the adsorption kinetics models for the removal of contaminants from aqueous solutions,” j. taiwan inst. chem. eng., vol. 74, pp. 25–48, 2017. [32] d. c. montgomery, e. a. peck, and g. g. vining, introduction to linear regression analysis. wiley, 2012. [33] b. samiey and s. farhadi, “kinetics and thermodynamics of adsorption of fuchsin acid on nickel oxide nanoparticles.,” acta chim. slov., vol. 60, no. 4, pp. 763–73, 2013. [34] l. khenniche and f. benissad-aissani, “adsorptive removal of phenol by coffee residue activated carbon and commercial activated carbon: equilibrium, kinetics, and thermodynamics,” j. chem. eng. data, vol. 55, no. 11, pp. 4677–4686, nov. 2010. https://www.sciencedirect.com/science/article/abs/pii/s1876107017300378 https://www.sciencedirect.com/science/article/abs/pii/s1876107017300378 https://www.sciencedirect.com/science/article/abs/pii/s1876107017300378 https://www.sciencedirect.com/science/article/abs/pii/s1876107017300378 https://journals.matheo.si/index.php/acsi/article/view/154 https://journals.matheo.si/index.php/acsi/article/view/154 https://journals.matheo.si/index.php/acsi/article/view/154 https://journals.matheo.si/index.php/acsi/article/view/154 https://pubs.acs.org/doi/abs/10.1021/je100302e https://pubs.acs.org/doi/abs/10.1021/je100302e https://pubs.acs.org/doi/abs/10.1021/je100302e https://pubs.acs.org/doi/abs/10.1021/je100302e https://pubs.acs.org/doi/abs/10.1021/je100302e https://pubs.acs.org/doi/abs/10.1021/je100302e h. a. and a. s. abbas / iraqi journal of chemical and petroleum engineering 22,4 (2021) 11 17 17 امتزاز الفالجيل على سطح الرماد المحضر من قشور الرز عباس صالححيدر عباس و عمار /كلية الهندسةبغدادامعة ج الخالصة للحصول والسعيللبيئة في عمل البحوث والصديقةمن الواضح البحث عن الطرق الرخيصة أصبحمؤخرا البحث تم هذاالنتائج ومن ضمن المهمة االمتصاص باستخدام مواد متوفرة و رخيصة. في أحسنعلى صناعة رماد قشور الرز بمواصفات عالية المتصاص المادة الفالجيل بعد تجفيف قشور الرز فياستخدام قشور . بعد الحصول على الرماد تم اجراء مئويةدرجة 600الفرن بدرجة حرارة مباستخداالرز يتم عملية الحرق ومعرفةفكرة عن خواصها مثل فحص حيود االشعة السينية وتكوينفحوص لمعرفة قابلية المادة لالمتصاص وفراندلجالسطحية للعينات. وتم استخدام طرق المعايرة للنتائج لمنحنيات لونكماير والمساحةالفراغات البينية عاليةة و عندما تكون درجات الحرارة معادالت الدرجة الثاني مباستخدااالفضل حيث كانت جالنتائاحسن ومعرفة ( و تم حساب االنثالبية و االنتروبية و طاقة كبس ورسم 25,30,45,65حيث استخدمت درجات الحرارة ) العالقات لتوضيح فعالية المادة في االمتصاص. االمتزازرز العنبر، فالجيل، قشر الرز، : لدالةاالكلمات available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.23 no.2 (june 2022) 9 – 17 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: osamah al-hashimi , email: o.a.alhashimi@2020.ljmu.ac.uk ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. constructed wetland units filled with waterworks sludge for remediating of wastewater contaminated with congo red dye ayad a. h. faisala, basim j. bedaha, osamah al-hashimib a department of environmental engineering, college of engineering, university of baghdad, iraq. b school of civil engineering and built environment, liverpool john moores university, liverpool l3 3af, uk. abstract the disposal of textile effluents to the surface water bodies represents the critical issue especially these effluents can have negative impacts on such bodies due to the presence of dyes in their composition. biological remediation methods like constructed wetl ands are more cost-effective and environmental friendly technique in comparison with traditional methods. the ability of vertical subsurface flow constructed wetlands units for treating of simulated wastewater polluted with congo red dye has been studied in this work. the units were packed with waterworks sludge bed that either be unplanted or planted with phragmites australis and typha domingensis. the efficacy of present units was evaluated by monitoring of do, temperature, cod and dye concentration in the effluents under the variation of detention time (1-5 day) and dye concentration (10-40 mg/l). the maximum removal of dye and cod were 98 and 82% respectively for 10 mg/l of congo red dye after five-day hydraulic retention time (hrt). the results have shown that the removal of cod and dye concentration significantly increased with higher contact time and lower dye concentration. the values of monitored parameters adopted to evaluate the wastewater quality (i.e. do, cod and congo red dye) are satisfied the requirements of irrigation water. the dye concentration variation in the effluent with contact time was formulated efficiently by grau kinetic model. functional groups (specified by ft-ir analysis) have a remarkable role in the entrapment of dye on the waterworks sludge bed. keywords: constructed wetland, phragmites australis, typha domingensis, and congo red dye. received on 19/04/2022, accepted on 05/06/2022, published on 30/06/2022 https://doi.org/10.31699/ijcpe.2022.2.2 1introduction “water pollution” represents the familiar threat to the global environment in the last decades. it means that there is deterioration in the quality of water resources (like surface water and groundwater) due to development adopted by human to improve all living aspects. for example, the disposal of wastewater resulted from domestic, commercial and industrial uses without applied proper treatment can cause severe pollution for receiving water bodies. the influences of this pollution are fatal for entire ecosystem not only for human life [1–6]. a dye is a colouring substance and it mostly applies as solution in water. pigments and dyes appear to be coloured due to absorption of specific wavelengths of light more than others especially in the visible spectrum (400–720 nm). moreover, the structure of dyes contains alternate single and double bonds; so, they show resonance property which considers the stabilization factor for organic compounds. for industrial and domestic requirements, the formation of dye (or colouration) and its favourable compounds in water are not acceptable according to many environmental regulations. colour can be imparted due to the presence of different dyeing substances such as tanning, dyes, lignin, inorganic pigments. the industries like pharmacological manufacturing, dye and dye intermediates [7], paper and pulp [8], kraft bleaching [9], tannery [10], fabric [11], cosmetics, paper, and rubber are different sectors that employ the dyes. congo red dye is the first synthetic dyestuffs of the direct type which previously utilized to dye cotton but then substituted by dyes more resistant to washing and light. at ph>5, the aqueous phase will have a red colour in the presence of this dye; however, the colour become blue at more acidic conditions. red dye is classified as an acidic anionic dye with chemical formula of c32h22n6na2o6s2. the molecular weight of this dye is 696.66 g/mol and the absorbance can be spectro-photometrically monitored at the maximum wavelength (λmax) equal to 497 nm. dye treatment is associated with many problems because most dyes are stable and non-biodegradable. several methods have investigated to treat dye-polluted wastewater, by physical and chemical processes, like flocculation with lime, coagulation, adsorption, ultrafiltration and reverse osmosis. these methods are limited in use due to the low efficiency, high cost and lack of applicability to avoid a variety of dyes in addition to the forming of toxic pollution resulted from excessive use of chemicals. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:o.a.alhashimi@2020.ljmu.ac.uk http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2022.2.2 faisal et al. / iraqi journal of chemical and petroleum engineering 23,2 (2022) 9 17 10 the adsorption method is implemented using bark, rice husk, activated carbon, peanut shell, charcoal, cotton waste, clay, banana waste, coconut shell and clay gas residue [12–14]. this technique is not useful because it only depends on transferring the dye from the liquid to solid phase. therefore, sorbent regeneration and subsequent treatment of solid waste must apply and these processes are costly. alternatively, biological approach is applied to treat dye wastewater because of its low cost, high efficacy and acceptable environmentally. constructed wetlands (cws) are engineering systems commonly utilized due to their simplicity, appropriateness, low operating cost and low energy requirements. these systems have been implemented to treat the wastewater through benefit from natural processes that cause an evidence reduction in the requirements for mechanical devices and energy. previous publications revealed the efficiency of cws in treating different types of wastewater like; urban runoff, animal wastewater and mine disposal [15,16], petroleum wastewater [17,18], textile wastewater [19] and domestic sewage [20,21]. treatment by cws mainly depends on the application of different aqueous species such as phragmites australis, eichhornia crapssipes, typhonium flagelliform, typha, azolla caroliniana, and lemnaetc for removing of dye and other pollutants from wastewater [22,23]. survey related with sludge of waterworks signified that the europe alone can generate several million tons every year of this byproduct and it is expected to increase drastically in the future. this sludge can dispose either to the sanitary landfills or to the river. accordingly, cheaper options have been proposed by water companies to minimize the problems associated with sludge disposal [24]. in this regard, the usage of this sludge as substrate in cws is one of these options which investigated in this work. hence, the main objective is achieved the experimental investigation supported with kinetic model for vertical flow cws filled with waterworks sludge to treat water polluted with congo red dye in the presence of typha domingensis and p. australis compared with units free from plants. 2materials and scheme of operation simulated wastewater was prepared with four different concentrations of congo red dye in the range from 10 to 40 mg/l. the characteristics of tap water utilized in the preparation of such wastewater were; ph=7.3, do=7.26 mg/l, temp.=17 °c, tds=523 mg/l and ec=1046 ds/cm. waterworks sludge fig. 1 was collected from groundwater reservoir in al-amin water supply treatment plant / baghdad/ iraq. this plant uses alum salt to purify raw water. the sludge was dried in the air for three days, crushed and grinded to be in size from 63 µm to 1 mm. coefficient of hydraulic conductivity, bulk density and porosity for this sludge were 2.93x10-4 m/s, 1.06 g/cm3 and 0.42 respectively. the pilot-scale units of cws were established during september of 2019 and, then, the planting stage has begun on 1 october 2019; however, the operation and monitoring processes were implemented in 1 december of the same year and extended to 31 march 2020. the operation process consists of two phases: a) the first phase (or acclimation period): this phase was continued about two months from 1 october to 30 november to enhance the acclimation of the plants (height ≈ 0.5 m). the plants were trimmed to a certain height and the removed parts can be returned to the experimental units. b) second phase: this phase requires to operate the cws units in batch mode for duration from 1 december 2019 until 31 march 2020 for different concentrations of influent congo red dye as mentioned previously. the batch tests were conducted with detention time equal to 5 days and the parameters like ph, temp., do, tds, ec, colour, cod, nh4-n, no3-n and dye concentration were chosen to evaluate the performance of treatment process. cod can be determined by “closed reflux 5220 c method” in “standard methods for the examination of water and wastewater and environmental chemistry”. the water temperature (oc) and do (mg/l) were measured by “hand-held mi 605 portable dissolved oxygen, martini (italy)”. the removal efficiency (r) of any measured parameter was calculated by the following equation: 𝑅 = 𝐶𝑒−𝐶𝑖 𝐶𝑖 × 100 (1) where: ce and ci are the effluent and influent values respectively. to determine the dye concentration (x) based on the absorbance (y) of uv-vis spectrophotometer, the calibration curve was constructed and the following fitted equation can be applied in the determination of concentration: y = 0.0414x − 0.0017, r² = 0.9958 (2) fig. 1. waterworks sludge from groundwater reservoir and complexes in al-amin/ baghdad/ iraq. faisal et al. / iraqi journal of chemical and petroleum engineering 23,2 (2022) 9 17 11 3description of cws units four identical plastic containers fig. 2 were utilized to represent the units of vssf cws with dimensions of; total height=60 cm, top diameter= 50 cm and bottom diameter= 40 cm. each unit was packed with coarse gravel (>10 mm) at the bottom to prevent the outlet clogging and; then, another layer of gravel (<10 mm) must situate on the previous layer. the outlet valve was located at the bottom of each unit somewhere above the base with 5 cm. this valve is utilized for sampling and to empty of treated water. it is connected with pvc pipe (12.5 mm in diameter) to specify the elevation of water in cw unit. perforated pvc tube (50 mm in diameter, 75 cm in length) was embedded in substrate of each unit to increase the aeration of bed [25]. the main bed is the waterworks sludge (ws) with the depth of 150 mm that packed above the gravel layers. one unit vegetates with phragmites australis while typha domingensis was inserted in the other unit. the remaining two units in each group were not vegetated and they can be used as control units. the planted units can be recognized from unplanted by subscript “p” with the first letter of the adopted plant. the first unit will be unplanted and operated with tap water only; so, the subscript “c” can be used to recognize it as a control unit. the water contaminated with soluble dye will be fed to the remaining three units. table 1 presents the adopted designations for describing the cws units to facilitate the discussion of obtained measured results. fig. 2. unplanted and planted units of cw installed in this work table 1. designations and details of cws units implemented in this work unit designation plant type influent cwwsc -----tap water cwws -----congo red-water cwwspp p. australis congo red-water cwwspt typha domingensis congo red-water 4operation of the system the polluted water was injected to the cw unit from top side and remained within this unit for 5 days which represents the “contact time”. this means that the wastewater poured for the first day of the operation cycle with closing the outlet valve and keeping the water for 5 days. the sample must be taken 30 ml of treated water after the end of each day by opening the “outlet valve” mentioned previously. between two successive tests, the unit must be free from the wastewater and this duration (= 2 weeks) named the “resting time” which required to obtain partially saturated conditions. after finishing the operation cycle, the outlet valve was opened and treated water can leave the cw along the day. as bed drains, the air is drawn into the bed and re-aerating the microbial. for the unplanted vertical subsurface flow cw units, the same previous working plan was achieved. 5kinetic modeling the biological and transport processes occurred within the cw unit can describe by the kinetic model [26]. the constants of such model are identified as the growth or bio-kinetic coefficients. several kinetic models are available in the previous studies to formulate the mentioned processes like “first-order model” and “grau second-order model” [27–29]. second-order model of grau (eq. 3) was applied in the current investigation for simulating the dye removal in terms of its concentrations with different values of hrt [30,31]: 𝑆𝑒 = 𝑆𝑖 (1 − 1 𝑏+ 𝑎 𝐻𝑅𝑇 ) (3) where: 𝑆𝑖 is the inlet concentration (mg/l), 𝑆𝑒 is solute concentration in effluent (mg/l). kinetic constants (𝑎 and b) have calculated through fitting eq. 3 with measured data by “solver” option in excel 2016. 6results and discussion 6.1. experimental measurements the density and height of plant increased dramatically with the age from 5 and 0.15 to be 41 plants/unit and 1.70 m respectively after 136 days for p. australis; however, these indicators were 32 plants/unit and 1.15 m beyond same duration for typha. the ph, temperature, do, tds, ec, cod, and red dye concentration monitored. regardless the hrt and dye concentration, the ph of treated water resulted from cwws, cwwspp, and cwwspt units lie in between 6.5 and 8.5 which represent who limits [32]. although the values of tds were increased beyond the treatment process; however, the measured maximum value of is equal to 748 mg/l which satisfies the prescribed value by who (2004) < 1000 mg/l. faisal et al. / iraqi journal of chemical and petroleum engineering 23,2 (2022) 9 17 12 in addition, the concentration of nitrates in simulated wastewater prior to the treatment by vssh cw packed with waterworks sludge was varied from 4.3 to 12.8 mg/l as dye concentration changed from 10 to 40 mg/l. however, these values of nitrates are satisfied the acceptable limit specified by who (< 50 mg/l) but unfortunately, they exceeded the prescribed standard of epa (< 0.05). results revealed that the removals of nitrate are improved with increase of hrt and decrease of influent concentration especially with presence of plant. for hrt of 5 days, when the influent concentration of nitrate equal to 4.3 mg/l the removal efficiencies have values of 61, 66 and 68% for treated water resulted from cwws, cwwspp and cwwspt units respectively. these removals will be equal to 53, 61 and 63% for same units and hrt when influent concentration of nitrate increased to become 12.8 mg/l; however, the decrease of hrt to be 1-day can reduce the removal percentages to become 45, 50 and 52% respectively. table 2 lists the inlet and outlet concentrations of do versus the detention time for adopted units of cw versus different dye concentrations. measurements certified that the influent concentrations of do in simulated wastewater are ranged from 7.45 to 7.9 mg/l and they decrease with increase of hrt because of consumption the oxygen in the degradation of organic contaminants which measured by cod and dye concentration. it is obvious that the minimum value for effluent concentrations of do reached to 3.98 mg/l which approximately consistent with epa standards (4-5 mg/l) as cited in usepa (2006) to ensure aerobic oxidation. table 3 and table 4 are signified that there is evident reduction in the concentrations of dye and cod; however, this reduction can be justified by reduction in do values. it seems that the presence of plant with increase of hrt can cause significant reduction in the organic contaminants for treated wastewater. table 2. concentrations of do versus contact time in the planted and unplanted units of cw filled with waterworks sludge as function of dye concentrations do (mg/l) hrt (day) cwws cwwspp cwwspt 10 20 30 40 10 20 30 40 10 20 30 40 influent 0 7.45 7.7 7.85 7.9 7.45 7.7 7.85 7.9 7.45 7.7 7.85 7.9 effluent 1 6.71 7.02 7.14 7.22 5.82 5.9 6.06 6.13 5.98 6.1 6.29 6.35 2 6.31 6.61 6.83 6.89 5.37 5.55 5.74 5.82 5.67 5.73 5.91 5.99 3 6.00 6.2 6.38 6.44 4.80 5.1 5.27 5.37 5.26 5.35 5.51 5.6 4 5.54 5.91 6.08 6.15 4.29 4.68 4.86 4.93 4.83 5.04 5.34 5.44 5 4.9 5.6 5.81 5.89 3.98 4.23 4.38 4.47 4.40 4.68 4.75 4.83 table 3. concentrations of cod versus contact time in the planted and unplanted units of cw filled with waterworks sludge as function of dye concentrations cod (mg/l) hrt (day) cwws cwwspp cwwspt 10 20 30 40 10 20 30 40 10 20 30 40 influent 0 30.51 70.34 102.33 126.2 30.51 70.34 102.33 126.2 30.51 70.34 102.33 126.2 effluent 1 16.59 39.98 62 78.5 9.44 22.4 35.5 47.32 9.31 20.9 35.3 46.43 2 16.02 38.54 59.65 76.22 8.11 19 33.25 43.16 7.86 18.66 32.33 41.89 3 14.7 36.02 57.07 72.69 6.88 18.14 30.9 41.26 6.37 17.86 29.78 39.75 4 14.15 35.45 53.51 69.25 6.53 16.74 26.81 37.97 6.05 15.96 25.78 35.91 5 13.78 34.22 51.57 65.35 6.21 15.34 24.96 33.81 5.5 13.71 24.04 32.35 min. removal (%) 46 43 39 38 69 68 65 63 69 70 66 63 max. removal (%) 55 51 50 48 80 78 76 73 82 80 77 74 table 4. concentrations with removal efficiencies of red dye versus the contact time in the planted and unplanted units of cw filled with waterworks sludge conc. of dye (mg/l) hrt (day) cwws cwwspp cwwspt influent 0 10 20 30 40 10 20 30 40 10 20 30 40 effluent 1 0.717 1.836 3.06 4.88 0.596 1.594 2.982 4.32 0.572 1.546 2.913 4.28 2 0.62 1.442 2.76 4.484 0.5 1.4 2.7 4 0.5 1.4 2.7 3.99 3 0.476 1.352 2.631 4.296 0.451 1.302 2.547 4.16 0.403 1.208 2.409 4 4 0.403 1.008 2.121 3.616 0.282 0.702 1.767 3.16 0.258 0.718 1.707 3.16 5 0.379 0.96 2.046 3.44 0.282 0.766 1.767 2.88 0.234 0.67 1.635 2.832 min. removal (%) 93 90 90 88 94 92 90 89 94 92 90 89 max. removal (%) 96 95 93 91 97 96 94 93 98 97 95 93 faisal et al. / iraqi journal of chemical and petroleum engineering 23,2 (2022) 9 17 13 additional unplanted cw unit filled with waterworks sludge (designated as cwwsc) was irrigated with tap water to be a “control” unit to evaluate performance of previous units. this unit can be specified the influence of dye presence on the tap water characteristics. measurements proved that the ph of tap water was 7.3 which reduced with elapsed time until reached to 7 beyond five days due to the co2 dissolution. the ph values were increased after one-day detention time and then began to decrease for units fed with contaminated water. this difference in behavior of ph between units fed with tap water only and that irrigated with contaminated water may be resulted from interaction between substrate and biofilm which caused initial increase in the ph for unit contained wastewater. other observations certified that the influent values of tds, ec, nh4-n and no3-n for tap water are equal to 523 mg/l, 1046 μs/cm, 0.33 mg/l, and 8.1 mg/l; however, these values are slightly different from that of wastewater entering to the cwws, cwwspp and cwwspt units. this difference may be related to the quality of water especially the tests on the control unit are conducted in the middle of march while on the units fed with wastewater in the january and february. this means that the addition of congo red dye will not have significant effects on the values of tds, ec, nh4-n and no3-n. results revealed that the tds and ec values were increased in the effluent from control units with percentage reached to 10% and also the values of nh4-n and no3-n have been decreased with maximum percentage of 40%. this behavior may be resulted from the activity of biomass due to the availability of cod (i.e. dye organic compound) and, in addition, the role of used vegetation. the monitoring process elucidates that the quantity of dissolved oxygen in the influent tap water for cwwsc unit conducted in march is 7.26 mg/l which slightly different from dye-water. this difference can be resulted from the change in the quality of tap water during testing months (i.e. january, february and march). high difference in the cod of influent according to dye concentration can be recognized; it has values of 30.51, 70.34, 102.33 and 126.2 mg/l for 10, 20, 30 and 40 mg/l dye concentrations respectively. the cod is equal to 7.21 mg/l for control unit. the big difference in the values of cod between simulated wastewater and tap water can be resulted from the presence of red dye. measurements for treated wastewater certified that the dissolved oxygen was reduced with detention time due to the consumption of do in the dye oxidation. the do and cod in the effluents for this unit at 5 days were 5.82 and 3.05 mg/l respectively. finally, the temperatures of influent and effluent for control unit were identical to values of other units irrigated with wastewater. 6.2. grau second-order kinetic model dye concentrations in effluent treated by planted and unplanted units (cws, cwspp, cwspt) are formulated by 2nd kinetic model of grau using “solver” in excel 2016. the constants of this model (𝑎 and b) plus determination coefficient (r2) and sum of squared error (sse) are major outcomes of fitting process. fig. 3. measurements with grau predictions for effluent dye concentrations versus detention time in the planted and unplanted units filled with waterworks sludge -5 0 5 10 15 20 25 30 35 40 0 1 2 3 4 5 e ff lu e n t d y e c o n c e n tr a ti o n ( m g /l ) hrt (day) a) cwws 10 mg/l grau model 20 mg/l grau model 30 mg/l grau model 40 mg/l grau model 10 mg/l experiment 20 mg/l experiment 30 mg/l experiment 40 mg/l experiment -5 0 5 10 15 20 25 30 35 40 0 1 2 3 4 5 e ff lu e n t d y e c o n c e n tr a ti o n ( m g /l ) hrt (day) b) cwwspp 10 mg/l grau model 20 mg/l grau model 30 mg/l grau model 40 mg/l grau model 10 mg/l experiment 20 mg/l experiment 30 mg/l experiment 40 mg/l experiment -5 0 5 10 15 20 25 30 35 40 0 1 2 3 4 5 e ff lu e n t d y e c o n c e n tr a ti o n ( m g /l ) hrt (day) c) cwwspt 10 mg/l grau model 20 mg/l grau model 30 mg/l grau model 40 mg/l grau model 10 mg/l experiment 20 mg/l experiment 30 mg/l experiment 40 mg/l experiment faisal et al. / iraqi journal of chemical and petroleum engineering 23,2 (2022) 9 17 14 the sse and r2 are suitable statistical indictors to find the concurrence between the predicted and measured concentrations. fig. 3 plotted the grau relationship between effluent dye concentrations versus hrt for adopted influent dye concentration in the cw units packed with waterworks sludge; however, constants resulted from fitting with r2 and sse have been inserted in table 5. fig. 3 with this table revealed that the model describes the experimental outcomes in acceptable manner. table 5. parameters of grau model for effluent dye concentrations versus time in the present units influent dye conc. (mg/l) cwws cwwspp cwwspt 𝑎 b r2 sse 𝑎 b r2 sse 𝑎 b r2 sse 10 0.0478 1.0331 0.8899 0.0093 0.0420 1.0250 0.7937 0.0158 0.0446 1.0208 0.7891 0.0184 20 0.0612 1.0430 0.9028 0.0495 0.0585 1.0347 0.6866 0.1977 0.0592 1.0319 0.7096 0.1833 30 0.0477 1.0702 0.7847 0.1605 0.0579 1.0588 0.7076 0.3627 0.0602 1.0547 0.7144 0.3822 40 0.0519 1.0921 0.7746 0.3280 0.04545 1.0814 0.5510 0.7408 0.0461 1.0796 0.6077 0.6058 6.3. overall performance of cw units results signified that the planted and unplanted cws packed with waterworks sludge have a satisfactory ability in the reclamation of red dye-wastewater. several parameters influenced on the performance of adopted units and, consequently, on the quality of treated wastewater such as influent concentration, hrt, and type of plant (phragmites australis and typha domingensis) under natural environmental conditions. in spite of these units operated under influent concentrations ≤ 40 mg/l, two additional tests with concentrations of 250 and 1000 mg/l are conducted for monitoring their ability in reduction of dye concentration. table 6 proves that the removal efficiencies of dye with influent concentration of 250 mg/l lie within the range (86.3-88.4%) for all units under consideration after retention time equal to 5 days; however, the increase of influent concentration to be 1000 mg/l will cause a decrease in these efficiencies to be ranged from 81.6 to 83.6%. the results proved that the plants have positive effect on the treatment process; however, p. australis and typha domingensis have approximately the same effect on the treated wastewater. ultimately, the treated effluents consider acceptable for irrigation according to standards of who (2004) and usepa (2006). another indicator that can be used to evaluate the current treatment feasibility is the difference in the degree of colour between effluent and influent. fig. 4 lists a set of photos for appearance of effluent and influent after detention time of 5 days for 40 mg/l influent dye concentration. it seems that the colour of the wastewater entering to all units is red which can remove with various percentages depended on the kind of cws units. table 6. overall performance of cw units at hrt 5 days for different influent dye concentrations conc. (mg/l) removal efficiency (%) cwws cwwspp cwwspt r e d d y e 10 96.2 97.2 97.7 20 95.2 96.2 96.7 30 93.2 94.1 94.6 40 91.4 92.8 92.9 250 86.3 87.6 88.4 1000 81.6 83.2 83.6 c o d 30.51 54.8 79.6 82.0 70.34 51.4 78.2 80.5 102.33 49.6 75.6 76.5 126.20 48.2 73.2 74.4 582 37.9 65.3 65.9 1422 37.9 65.3 65.9 fig. 4. appearance of wastewater after 5 days for dye concentration in influent of 40 mg/l 7functional groups for virgin waterworks sludge, the spectrum of ir fig. 5 elucidates that the existence of o-h peak intensity in the broader range from 3400 to 3700 cm-1. this indicates the presence of hydrated aluminum silicates or an amorphous silicate material. the bending mode of h2o molecules can result from the band at 1626 cm-1. also, asymmetric stretching vibrations of silica (si–o–si) is recognized due to band at 1000–1085 cm-1. however, silica and quartz can be identified in the range of bands 460–500 and 770– 796 cm-1 respectively [33]. faisal et al. / iraqi journal of chemical and petroleum engineering 23,2 (2022) 9 17 15 on the other hand, the change in the intensity of waterworks sludge may be due to the interaction with the functional group of organic matter (residual of the root in sample) such as nh, c=c and c-c. while the test of ftir after and before dye sorption signifies the existence of peaks at 1431.2 and 2873.9 cm-1 (i.e. c=c in the dye aromatic ring). also, shifts in other peaks reveal the sorption of dye on the silanol group. fig. 5. spectrums of ft-ir outputs for waterworks sludge of planted and unplanted beds before and after dye removal 8conclusions the outputs of this work demonstrated the ability of cultivated and uncultivated wetland unit with a vertical subsurface flow in the treatment of textile wastewater in terms of congo red dye concentration, dissolved oxygen, cod. concentrations of red dye have been selected with range from 10 to 40 mg/l with removal efficiency exceeded 88% for 1-day detention period, and this value increased with increasing detention time and decreasing dye concentration. observations showed that the phragmites australis and typha domingensis used in the experimental units had roughly the same effect on the monitoring parameters adopted to assess the quality of the treated wastewater. also, there is a slight difference in the performance of the cultivated and non-cultivated units on the effluent quality of cw. an apparent decrease in cod values (at least 38%) was identified for the current units at a dye concentration of 10 mg/l for the lowest value of contact time; however, this decrease is associated with a depletion in the dissolved oxygen values that are consumed in the decomposition process. according to several agency guidelines, effluents based on ph, cod, and dye concentration values are suitable for irrigation purposes. grau second-order kinetic model was well described the variation of effluent dye concentration with hrt for present units. ft-ir analysis demonstrated that several functional groups enhanced dye uptake specifically identical to sio2. acknowledgments we are sincerely grateful to the environmental engineering department, university of baghdad for technical support. references [1] sulaymon, a.h., faisal, a.a.h., and khaliefa, q.m. (2015) cement kiln dust (ckd)-filter sand permeable reactive barrier for the removal of cu(ii) and zn(ii) from simulated acidic groundwater. journal of hazardous materials. 297 160–172. [2] rahi, m.a. and faisal, a.a.h. (2019) performance of subsurface flow constructed wetland systems in the treatment of al-rustumia municipal wastewater using continuous loading feed. iraqi journal of chemical and petroleum engineering. 20 (2), 33 – 40. [3] rahi, m.a. and faisal, a.a.h. (2019) using horizontal subsurface flow constructed wetland system in the treatment of municipal wastewater for agriculture purposes. iraqi journal of agricultural sciences. 50 (4),. [4] rahi, m.a., faisal, a.a.h., naji, l.a., almuktar, s.a., abed, s.n., and scholz, m. (2020) biochemical performance modelling of non-vegetated and vegetated vertical subsurface-flow constructed wetlands treating municipal wastewater in hot and dry climate. journal of water process engineering. 33. [5] al-hashimi, o., hashim, k., loffill, e., marolt čebašek, t., nakouti, i., faisal, a.a.h., et al. (2021) a comprehensive review for groundwater contamination and remediation: occurrence, migration and adsorption modelling. molecules. 26 (19), 5913. [6] hassan, w., faisal, a., abed, e., al-ansari, n., and saleh, b. (2021) new composite sorbent for removal of sulfate ions from simulated and real groundwater in the batch and continuous tests. molecules. 26 (14), 4356. [7] bedah, b.j. and faisal, a.a.h. (2020) use of vertical subsurface flow constructed wetland for reclamation of wastewater contaminated with congo red dye. plant archives. 20 (2), 8784–8792. [8] kolpin, d.w., furlong, e.t., meyer, m.t., thurman, e.m., zaugg, s.d., barber, l.b., et al. (2002) pharmaceuticals, hormones, and other organic wastewater contaminants in u.s. streams, 1999−2000: a national reconnaissance. environmental science & technology. 36 (6), 1202– 1211. [9] ali, m. and sreekrishnan, t.. (2001) aquatic toxicity from pulp and paper mill effluents: a review. advances in environmental research. 5 (2), 175–196. [10] routh, t. (2000) anaerobic treatment of vegetable tannery wastewater by uasb process. j. environ prot. 20 (2), 115–123. [11] zhang, q. and chuang, k.t. (2001) adsorption of organic pollutants from effluents of a kraft pulp mill on activated carbon and polymer resin. advances in environmental research. 5 (3), 251–258. 0 50 100 150 200 400 800 1200 1600 2000 2400 2800 3200 3600 4000 % t r a n sm it ta n c e wavenumber (cm-1) virgin waterworks sludge cwws cwwspp cwwspt https://www.sciencedirect.com/science/article/abs/pii/s0304389415003593 https://www.sciencedirect.com/science/article/abs/pii/s0304389415003593 https://www.sciencedirect.com/science/article/abs/pii/s0304389415003593 https://www.sciencedirect.com/science/article/abs/pii/s0304389415003593 https://www.sciencedirect.com/science/article/abs/pii/s0304389415003593 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/548 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/548 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/548 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/548 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/548 https://www.iasj.net/iasj/download/8846d9786d359bc4 https://www.iasj.net/iasj/download/8846d9786d359bc4 https://www.iasj.net/iasj/download/8846d9786d359bc4 https://www.iasj.net/iasj/download/8846d9786d359bc4 https://www.iasj.net/iasj/download/8846d9786d359bc4 https://www.sciencedirect.com/science/article/abs/pii/s2214714419309079 https://www.sciencedirect.com/science/article/abs/pii/s2214714419309079 https://www.sciencedirect.com/science/article/abs/pii/s2214714419309079 https://www.sciencedirect.com/science/article/abs/pii/s2214714419309079 https://www.sciencedirect.com/science/article/abs/pii/s2214714419309079 https://www.sciencedirect.com/science/article/abs/pii/s2214714419309079 https://www.mdpi.com/1420-3049/26/19/5913 https://www.mdpi.com/1420-3049/26/19/5913 https://www.mdpi.com/1420-3049/26/19/5913 https://www.mdpi.com/1420-3049/26/19/5913 https://www.mdpi.com/1420-3049/26/19/5913 https://www.mdpi.com/1420-3049/26/14/4356 https://www.mdpi.com/1420-3049/26/14/4356 https://www.mdpi.com/1420-3049/26/14/4356 https://www.mdpi.com/1420-3049/26/14/4356 https://www.mdpi.com/1420-3049/26/14/4356 http://www.plantarchives.org/20-2/8784-8792%20(6943).pdf http://www.plantarchives.org/20-2/8784-8792%20(6943).pdf http://www.plantarchives.org/20-2/8784-8792%20(6943).pdf http://www.plantarchives.org/20-2/8784-8792%20(6943).pdf https://pubs.acs.org/doi/abs/10.1021/es011055j https://pubs.acs.org/doi/abs/10.1021/es011055j https://pubs.acs.org/doi/abs/10.1021/es011055j https://pubs.acs.org/doi/abs/10.1021/es011055j https://pubs.acs.org/doi/abs/10.1021/es011055j https://pubs.acs.org/doi/abs/10.1021/es011055j https://pubs.acs.org/doi/abs/10.1021/es011055j https://www.sciencedirect.com/science/article/abs/pii/s1093019100000551 https://www.sciencedirect.com/science/article/abs/pii/s1093019100000551 https://www.sciencedirect.com/science/article/abs/pii/s1093019100000551 https://www.sciencedirect.com/science/article/abs/pii/s1093019100000599 https://www.sciencedirect.com/science/article/abs/pii/s1093019100000599 https://www.sciencedirect.com/science/article/abs/pii/s1093019100000599 https://www.sciencedirect.com/science/article/abs/pii/s1093019100000599 faisal et al. / iraqi journal of chemical and petroleum engineering 23,2 (2022) 9 17 16 [12] lorimer, j.p., mason, t.j., plattes, m., phull, s.s., and walton, d.j. (2001) degradation of dye effluent. pure and applied chemistry. 73 (12), 1957– 1968. [13] velmurugan, p., rathinakumar, v., and dhinakaran, g. (2011) dye removal from aqueous solution using low cost adsorbent. international journal of environmental sciences. 1 (7), 1492–1503. [14] yaneva, z.l. and georgieva, n.v. (2012) insights into congo red adsorption on agro-industrial materialsspectral, equilibrium, kinetic, thermodynamic, dynamic and desorption studies. a review. international review of chemical engineering. 4 (2), 127–146. [15] mays, p. and edwards, g. (2001) comparison of heavy metal accumulation in a natural wetland and constructed wetlands receiving acid mine drainage. ecological engineering. 16 (4), 487–500. [16] rozema, e.r., vanderzaag, a.c., wood, j.d., drizo, a., zheng, y., madani, a., et al. (2016) constructed wetlands for agricultural wastewater treatment in northeastern north america: a review. water. 8 (5), 1–14. [17] al-isawi, r., scholz, m., wang, y., and a. sani (2015) clogging of vertical-flow constructed wetlands treating urban wastewater contaminated with a diesel spill. environmental science and pollution research. 22 (17), 12779–12803. [18] al-isawi, r., sani, a., almuktar, s., and m. scholz (2015) vertical-flow constructed wetlands treating domestic wastewater contaminated by hydrocarbons. water science and technology. 71 (6), 938–946. [19] davies, l.c., cabrita, g., ferreira, r., carias, c., novais, j., martins-, s., et al. (2009) integrated study of the role of phragmites australis in azo-dye treatment in a constructed wetland: from pilot to molecular scale. ecological engineering. 35 (6), 961– 970. [20] sani, a., scholz, m., and bouillon, l. (2013) seasonal assessment of experimental vertical-flow constructed wetlands treating domestic wastewater. bioresource technology. 147 585–596. [21] paing, j., guilbert, a., gagnon, v., and chazarenc, f. (2015) effect of climate, wastewater composition, loading rates, system age and design on performances of french vertical flow constructed wetlands: a survey based on 169 full scale systems. ecological engineering. 80 46–52. [22] rai, p.k. (2008) heavy metal pollution in aquatic ecosystems and its phytoremediation using wetland plants: an ecosustainable approach. international journal of phytoremediation. 10 (2), 133–160. [23] azeez, n.m. and sabbar, a.a. (2012) the efficiency of duckweed (lemna minor l.) in phytotreatment of wastewater pollutants from basrah oil refinery. journal of applied phytotechnology in environmental sanitation. 1 (4), 163–172. [24] basibuyuk, m. and kalat, d.g. (2004) the use of waterworks sludge for the treatment of vegetable oil refinery industry wastewater. environmental technology. 25 (3), 373–380. [25] stefanakis, a.i. and tsihrintzis, v.a. (2012) effects of loading, resting period, temperature, porous media, vegetation and aeration on performance of pilot-scale vertical flow constructed wetlands. chemical engineering journal. 181–182 416–430. [26] acharya, b.k., pathak, h., mohana, s., shouche, y., singh, v., and madamwar, d. (2011) kinetic modelling and microbial community assessment of anaerobic biphasic fixed film bioreactor treating distillery spent wash. water research. 45 (14), 4248– 4259. [27] büyükkamaci, n. and filibeli, a. (2002) determination of kinetic constants of an anaerobic hybrid reactor. process biochemistry. 38 (1), 73–79. [28] sandhya, s. and swaminathan, k. (2006) kinetic analysis of treatment of textile wastewater in hybridcolumn upflow anaerobic fixed bed reactor. chem. eng. j. 122 87–92. [29] jafarzadeh, m.t., mehrdad, n., and hashemian, s.j. (2009) kinetic constants of anaerobic hybrid reactor treating petrochemical waste. asian j. chem. 21 (3), 1672–1684. [30] ni, s.-q., sung, s., yue, q.-y., and gao, b.-y. (2012) substrate removal evaluation of granular anammox process in a pilot-scale upflow anaerobic sludge blanket reactor. ecological engineering. 38 (1), 30–36. [31] nor faekah, i., fatihah, s., and mohamed, z.s. (2020) kinetic evaluation of a partially packed upflow anaerobic fixed film reactor treating low-strength synthetic rubber wastewater. heliyon. 6 (3), e03594. [32] world health organization (2004) guidelines for drinking-water quality. volume 1. recommendations. who. 1. [33] alshammari, m., al juboury, m.f., naji, l.a., faisal, a.a.h., zhu, h., al-ansari, n., et al. (2020) synthesis of a novel composite sorbent coated with siderite nanoparticles and its application for remediation of water contaminated with congo red dye. international journal of environmental research. 14 (2), 177–191. https://www.degruyter.com/document/doi/10.1351/pac200173121957/html https://www.degruyter.com/document/doi/10.1351/pac200173121957/html https://www.degruyter.com/document/doi/10.1351/pac200173121957/html https://www.degruyter.com/document/doi/10.1351/pac200173121957/html http://hristov.com/jordan/pdfs/insights%20into%20congo%20red%20adsorption%20on%20agro-industrial%20materials.pdf http://hristov.com/jordan/pdfs/insights%20into%20congo%20red%20adsorption%20on%20agro-industrial%20materials.pdf http://hristov.com/jordan/pdfs/insights%20into%20congo%20red%20adsorption%20on%20agro-industrial%20materials.pdf http://hristov.com/jordan/pdfs/insights%20into%20congo%20red%20adsorption%20on%20agro-industrial%20materials.pdf http://hristov.com/jordan/pdfs/insights%20into%20congo%20red%20adsorption%20on%20agro-industrial%20materials.pdf http://hristov.com/jordan/pdfs/insights%20into%20congo%20red%20adsorption%20on%20agro-industrial%20materials.pdf https://www.sciencedirect.com/science/article/abs/pii/s0925857400001129 https://www.sciencedirect.com/science/article/abs/pii/s0925857400001129 https://www.sciencedirect.com/science/article/abs/pii/s0925857400001129 https://www.sciencedirect.com/science/article/abs/pii/s0925857400001129 https://www.mdpi.com/2073-4441/8/5/173 https://www.mdpi.com/2073-4441/8/5/173 https://www.mdpi.com/2073-4441/8/5/173 https://www.mdpi.com/2073-4441/8/5/173 https://www.mdpi.com/2073-4441/8/5/173 https://link.springer.com/article/10.1007/s11356-014-3732-8 https://link.springer.com/article/10.1007/s11356-014-3732-8 https://link.springer.com/article/10.1007/s11356-014-3732-8 https://link.springer.com/article/10.1007/s11356-014-3732-8 https://link.springer.com/article/10.1007/s11356-014-3732-8 https://iwaponline.com/wst/article-abstract/71/6/938/18853/vertical-flow-constructed-wetlands-treating https://iwaponline.com/wst/article-abstract/71/6/938/18853/vertical-flow-constructed-wetlands-treating https://iwaponline.com/wst/article-abstract/71/6/938/18853/vertical-flow-constructed-wetlands-treating https://iwaponline.com/wst/article-abstract/71/6/938/18853/vertical-flow-constructed-wetlands-treating https://iwaponline.com/wst/article-abstract/71/6/938/18853/vertical-flow-constructed-wetlands-treating https://www.sciencedirect.com/science/article/abs/pii/s0925857408001687 https://www.sciencedirect.com/science/article/abs/pii/s0925857408001687 https://www.sciencedirect.com/science/article/abs/pii/s0925857408001687 https://www.sciencedirect.com/science/article/abs/pii/s0925857408001687 https://www.sciencedirect.com/science/article/abs/pii/s0925857408001687 https://www.sciencedirect.com/science/article/abs/pii/s0925857408001687 https://www.sciencedirect.com/science/article/abs/pii/s0960852413013060 https://www.sciencedirect.com/science/article/abs/pii/s0960852413013060 https://www.sciencedirect.com/science/article/abs/pii/s0960852413013060 https://www.sciencedirect.com/science/article/abs/pii/s0960852413013060 https://www.sciencedirect.com/science/article/abs/pii/s0925857414005655 https://www.sciencedirect.com/science/article/abs/pii/s0925857414005655 https://www.sciencedirect.com/science/article/abs/pii/s0925857414005655 https://www.sciencedirect.com/science/article/abs/pii/s0925857414005655 https://www.sciencedirect.com/science/article/abs/pii/s0925857414005655 https://www.sciencedirect.com/science/article/abs/pii/s0925857414005655 https://www.tandfonline.com/doi/abs/10.1080/15226510801913918 https://www.tandfonline.com/doi/abs/10.1080/15226510801913918 https://www.tandfonline.com/doi/abs/10.1080/15226510801913918 https://www.tandfonline.com/doi/abs/10.1080/15226510801913918 https://www.tandfonline.com/doi/abs/10.1080/15226510801913918 https://www.researchgate.net/profile/nayyef-azeez/publication/332539934_efficiency_of_duckweed_lemna_minor_l_in_phytotreatment_of_wastewater_pollutants_from_basrah_oil_refinery/links/5cbb01284585156cd7a4efdb/efficiency-of-duckweed-lemna-minor-l-in-phytotreatment-of-wastewater-pollutants-from-basrah-oil-refinery.pdf https://www.researchgate.net/profile/nayyef-azeez/publication/332539934_efficiency_of_duckweed_lemna_minor_l_in_phytotreatment_of_wastewater_pollutants_from_basrah_oil_refinery/links/5cbb01284585156cd7a4efdb/efficiency-of-duckweed-lemna-minor-l-in-phytotreatment-of-wastewater-pollutants-from-basrah-oil-refinery.pdf https://www.researchgate.net/profile/nayyef-azeez/publication/332539934_efficiency_of_duckweed_lemna_minor_l_in_phytotreatment_of_wastewater_pollutants_from_basrah_oil_refinery/links/5cbb01284585156cd7a4efdb/efficiency-of-duckweed-lemna-minor-l-in-phytotreatment-of-wastewater-pollutants-from-basrah-oil-refinery.pdf https://www.researchgate.net/profile/nayyef-azeez/publication/332539934_efficiency_of_duckweed_lemna_minor_l_in_phytotreatment_of_wastewater_pollutants_from_basrah_oil_refinery/links/5cbb01284585156cd7a4efdb/efficiency-of-duckweed-lemna-minor-l-in-phytotreatment-of-wastewater-pollutants-from-basrah-oil-refinery.pdf https://www.researchgate.net/profile/nayyef-azeez/publication/332539934_efficiency_of_duckweed_lemna_minor_l_in_phytotreatment_of_wastewater_pollutants_from_basrah_oil_refinery/links/5cbb01284585156cd7a4efdb/efficiency-of-duckweed-lemna-minor-l-in-phytotreatment-of-wastewater-pollutants-from-basrah-oil-refinery.pdf https://www.tandfonline.com/doi/abs/10.1080/09593330409355471 https://www.tandfonline.com/doi/abs/10.1080/09593330409355471 https://www.tandfonline.com/doi/abs/10.1080/09593330409355471 https://www.tandfonline.com/doi/abs/10.1080/09593330409355471 https://www.sciencedirect.com/science/article/abs/pii/s1385894711015105 https://www.sciencedirect.com/science/article/abs/pii/s1385894711015105 https://www.sciencedirect.com/science/article/abs/pii/s1385894711015105 https://www.sciencedirect.com/science/article/abs/pii/s1385894711015105 https://www.sciencedirect.com/science/article/abs/pii/s1385894711015105 https://www.sciencedirect.com/science/article/abs/pii/s0043135411003228 https://www.sciencedirect.com/science/article/abs/pii/s0043135411003228 https://www.sciencedirect.com/science/article/abs/pii/s0043135411003228 https://www.sciencedirect.com/science/article/abs/pii/s0043135411003228 https://www.sciencedirect.com/science/article/abs/pii/s0043135411003228 https://www.sciencedirect.com/science/article/abs/pii/s0043135411003228 https://www.sciencedirect.com/science/article/abs/pii/s003295920200047x https://www.sciencedirect.com/science/article/abs/pii/s003295920200047x https://www.sciencedirect.com/science/article/abs/pii/s003295920200047x https://www.sciencedirect.com/science/article/abs/pii/s1385894706001641 https://www.sciencedirect.com/science/article/abs/pii/s1385894706001641 https://www.sciencedirect.com/science/article/abs/pii/s1385894706001641 https://www.sciencedirect.com/science/article/abs/pii/s1385894706001641 https://www.sciencedirect.com/science/article/abs/pii/s0925857411003326 https://www.sciencedirect.com/science/article/abs/pii/s0925857411003326 https://www.sciencedirect.com/science/article/abs/pii/s0925857411003326 https://www.sciencedirect.com/science/article/abs/pii/s0925857411003326 https://www.sciencedirect.com/science/article/abs/pii/s0925857411003326 https://www.sciencedirect.com/science/article/pii/s2405844020304394 https://www.sciencedirect.com/science/article/pii/s2405844020304394 https://www.sciencedirect.com/science/article/pii/s2405844020304394 https://www.sciencedirect.com/science/article/pii/s2405844020304394 https://books.google.com.tr/books?hl=en&lr=&id=sj76cotm-nqc&oi=fnd&pg=pr15&dq=%5b32%5d%09world+health+organization+(2004)+guidelines+for+drinking-water+quality.+volume+1.+recommendations.+who.+1.+&ots=v9t_net7z8&sig=wwpeehdouks5otkwkuowwm8hwjs&redir_esc=y#v=onepage&q&f=false https://books.google.com.tr/books?hl=en&lr=&id=sj76cotm-nqc&oi=fnd&pg=pr15&dq=%5b32%5d%09world+health+organization+(2004)+guidelines+for+drinking-water+quality.+volume+1.+recommendations.+who.+1.+&ots=v9t_net7z8&sig=wwpeehdouks5otkwkuowwm8hwjs&redir_esc=y#v=onepage&q&f=false https://books.google.com.tr/books?hl=en&lr=&id=sj76cotm-nqc&oi=fnd&pg=pr15&dq=%5b32%5d%09world+health+organization+(2004)+guidelines+for+drinking-water+quality.+volume+1.+recommendations.+who.+1.+&ots=v9t_net7z8&sig=wwpeehdouks5otkwkuowwm8hwjs&redir_esc=y#v=onepage&q&f=false https://link.springer.com/article/10.1007/s41742-020-00245-6 https://link.springer.com/article/10.1007/s41742-020-00245-6 https://link.springer.com/article/10.1007/s41742-020-00245-6 https://link.springer.com/article/10.1007/s41742-020-00245-6 https://link.springer.com/article/10.1007/s41742-020-00245-6 https://link.springer.com/article/10.1007/s41742-020-00245-6 https://link.springer.com/article/10.1007/s41742-020-00245-6 faisal et al. / iraqi journal of chemical and petroleum engineering 23,2 (2022) 9 17 17 وحدات األراضي الرطبة المعبأة بخبث محطات معالجة المياه لمعالجة مياه الصرف الملوثة بصبغة الكونغو الحمراء اياد عبد الحمزة فيصل1 و باسم جابر بدح1 و أسامة الهاشمي2 1 قسم الهندسة البيئية/كلية الهندسة/ جامعة بغداد 2 جامعة جون مور، ليفربول الخالصة يمثل التخلص من النفايات السائلة النسيجية في االجسام المائية السطحية قضية حرجة ألن لها تأثيرات سلبية على تلك االجسام الحتواء تلك النفايات على االصباغ. تعتبر طرق المعالجة البيولوجية مثل األراضي الرطبة الطرق التقليدية. تمت دراسة قدرة وحدات األراضي المشيدة أكثر فعالية من حيث التكلفة وصديقة للبيئة مقارنة ب الرطبة الُمنشأة ذات التدفق تحت السطحي العمودي على معالجة المياه العادمة المحاكاة الملوثة بصبغة الكونغو أو مزروعة غير تكون أن إما التي الصحي الصرف مياه أحواض بمخلفات معبأة الوحدات كانت الحمراء. والتي تعتبر مألوفة في بيئة العراق. تم تقييم typha domingensisو phragmites australisمزروعة مع في والصبغة العضوية والمادة الحرارة ودرجة المذاب األكسجين تركيز مراقبة خالل من الوحدات هذه فعالية تر(. كان الحد مجم / ل 40-10أيام( وتركيز الصبغة ) 5-1النفايات السائلة في ظل اختالف وقت االحتجاز ) العضوية والمادة الصبغة في للتخفيضات لـ 82و 98األقصى التوالي على صبغة ٪10 من لتر / ملجم وتركيز الصبغة زاد codالكونغو الحمراء بعد خمسة أيام وقت التالمس هيدروليكي. أظهرت النتائج أن إزالة ت الصبغة. تركيز وانخفاض التالمس وقت ارتفاع مع ملحوظ لتقييم بشكل المعتمدة المراقبة المعلمات قيم لبي )أي الصحي الصرف مياه صياغة do ،codجودة تمت الري. مياه متطلبات الحمراء( الكونغو وصبغة بكفاءة بواسطة نموذج الحركي. grauاختالف تركيز الصبغة في التدفق مع وقت التالمس للوحدات الحالية لها دور ملحوظ في احتجاز الصبغة على طبقة الحمأة ft-irاختبار المجموعات الوظيفية المحددة بواسطة الخاصة بالمحطات المائية. الكلمات الدالة: األراضي الرطبة، القصب، البردي، صبغة الكونغو الحمراء. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.23 no.4 (december 2022) 1 – 6 eissn: 2618-0707, pissn: 1997-4884 corresponding author: name: kasi njeudjang , email: kasinj2006@yahoo.fr ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. remediation of oil production by matrix acidizing method on an oil well kasi njeudjanga, justine yandjimainb, madeleine nitcheuc, and théophile ndougsambargab a department of quality industrial safety and environment. national advanced school of mines and petroleum industries. university of maroua. po. box: 46,maroua, cameroon b department of physics, advanced teacher’s training college, university of yaoundé i, po. box 47, yaoundé, cameroon c department of basic scientific teaching, school of geology and mining engineering, university of ngaoundere, p.o. box 115 meiganga, cameroon abstract the remediation oil production by matrix acidizing method on the well named "x" (for confidential reasons) is scrutinized in this paper. initial production of 1150 bpd, production index of 2.8 stb/psi/d and permeability of 150md, in 2018 two years down the lane this dropped to 450 bpd, production index 0.7 stb/psi/d. the declined observed on the production index is trouble shouted and after elimination of (no completion damage/perforation damage), the skin is calculated by carrying out a well test (build-up test) whose extrapolation in excel over times gave us a skin of 40.the reservoir heterogeneity, containing >20% of feldspar, carbonates and paraffin’s guided thematrix acidizing design and treatment proposition to remedy this problem. a positive displacement pump (ht400), boosted by a centrifugal pump were used to pump the acid treatment through high pressure treating line downhole. halliburton insite for stimulation the (ifs) software monitored treating pressure and surface flow rate, keeping injection rate below fracturing pressure. pipesim software is used to run the nodal analysis before and after treatment this helped to forecast optimal production rates and pressure after treatments. matrix acidizing method applied on the well x increased the production to 850 bpd with production index of 2 std/psi/d, skin 1.5. the economic benefit to the company stood at (profit oil 21,699,500 usd.) over a two years period of production. meanwhile uncertainties in demand and supply of crude oil at the international market cause constant fluctuation in oil prices, this should be strongly considered upon execution of this project. overall applications of this acidizing treatment can be carried out on reservoirs with similar mineralogy. hcl/hf blend dissolves sandstone, mud stone and calcite minerals thus reservoir porosity and permeability can be enhanced in regions extending several meters around the injection well. keywords: flow rate, matrix acidizing method, skin, productivity index, well, fluid dynamics. received on 25/07/2022, accepted on 03/12/2022, published on 30/12/2022 https://doi.org/10.31699/ijcpe.2022.4.1 1introduction the world energy demand increases by 1, 4% per year (iea; 2008) with over 60% constituted of hydrocarbons [1-3]. decline experienced in the oil and gas production coupled, (little/no oil field development in contemporary era, formation damages. according to the international energy agency, the world energy demand will continue to increase from 0,7 to 1,4% per year between 2008 to 2035 following different scenarios envisaged, however this will be dominated by fossil energy, notably hydrocarbons, though with a decline envisage [4-6]. with the continue increase in world demand for hydrocarbon coupled with an annual decline in exploration and drilling of new wells. stakeholders have developed technologies/methods to sustain oil production in a more economic and profitable way, one of which is matrix acidizing [7-10]. an acidizing treatment is called a “matrix” treatment because the acid is injected at pressures below the parting pressure of the formation so that fractures are not created. matrix acidizing can significantly enhance the productivity of a well when near-wellbore formation damage is present and, conversely, is of little benefit in an undamaged well [11-15]. the main goal of matrix acidizing is to restore and improve the formation’s productivity by removing the near-wellbore damage and creating flow channels (wormholes) in carbonate formations [16]. several factors must be considered in the process of choosing an adequate acid, for instance, temperature, pressure, crude composition, formation permeability, acid/crude compatibility, acid/additive compatibility, and compatibility between additives [17]. in matrix acidizing, the production of single and dominant wormholes is preferred. previous experimental studies in the literature have shown the existence of an optimal acid injection rate at which maximum wormholing efficiency is produced [18-22]. hence, the purpose of many laboratories’ research focuses on finding this optimal injection rate, which could be defined as the injection rate that would produce the best wormhole with the lowest volume of acid. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:kasinj2006@yahoo.fr http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2022.4.1 k. njeudjang et al. / iraqi journal of chemical and petroleum engineering 23,4 (2022) 1 6 2 matrix acidizing method is applied in field named "y" (for confidential reasons and its location not given) to enhance productivity and maximise recovery in its mature fields thus generating extra production capacity and restore original productivity in damage wells. the aim of this paper is therefore to remedy oil production by matrix acidizing method on the well x which belongs to the field y and in an efficient manner. the objectives of this paper are as follows: perform the nodal analysis to affirm the present state of this well (current permeability and production index); justify the choice of matrix acidizing by (13.5: 1.5% hcl:hf blend); perform the acid stimulation design (acid volumes and strengths); execute the acid stimulation job; perform well testing (build –up test) and run the nodal analysis to ascertain treated well ameliorated parameters (permeability and production index) and perform an economic evaluation. to successfully achieve the set goals, this paper is divided into three sections: the first section deals with the introduction, the second section presents the data, tools and the obtained results. the paper ends by general conclusion. 2data, methods and result the well x was worked over in 2018 and has never been stimulated, after completion the well-produced, with water production trend decreasing while oil production increasing. before the production got stabilized, choke was opened, water production increased while we witnessed a drop in oil percentage. the well x is an oil producer well. before the production got stabilized, choke was opened and then water production started increasing and oil decreasing. this suggests a possible water coning and water flow suggests presence of scales and suspected damage mechanism could be fines migration. thus a drop in draw down at the level of the perforations which is choked due to drop in pressure and temperatures experienced at this node. oil sample provided was an emulsion made of 40% water and 60% of oil. no incompatibility was observed when mixed to different fluids. however moderate sludge was observed with 10%hcl, with no rust added. based on the lab testing, solvent preflush (xylene + diesel) and an emulsifier is added to the injectivity test fluid and in the non-acidic preflush, as they will be the first aqueous fluids to interact with the formation. main treatment proposed for lra007 is 13.5:1.5% hcl: hf blend. this blend helps to remove damage from fines and clays as they might have accumulated near wellbore and reducing production on this formation. it contains acetic acid used to control aluminum scaling and iron precipitation, surfactant, clay and fines control additive. table 1 presents the well x data. the excel software, ifs software, pipesim software, matrix acidizing method and economic evaluation are used to attain the aims of this paper. this is made possible through the presentation of the injection path from surface lines to downhole, description and interpretation of the different graph’s obtained before and after acidification and at the end present the economic evaluation. table 1. well x data well data well name x field y well type oil producer well treatment type matrix acidizing completion data xmas tree fmc 3 1/8” 5k tubing 3 1/2" l80 9.2# vam tubing volume 60 bbl perforated interval data height 10,000 ft md/sv top 10,500fttvd/sv total length 14.4m reservoir data permeability(k) before treatment 150md permeability(k) after treatment 50 md porosity 29% bht 200 degf skin before treatment 40 skin after treatment -1.5 ks1 0.04k height (h) 48ft rw 0.5ft rs 2ft re 2000 ft oil formation volume factor 1.2 gas oil ratio 500 viscosity of oil 1.2cp viscosity of acid 1.7cp bhtp 1171.6 psi frac gradient 0.33 psi/ft frac pressure 3500 psi hydrostatic pressure (with pad acid) 2078 psi friction pressure @ 4bpm 210psi maximum surface pressure 1632psi 80% safety factor 1305psi production data oil flow rate 457 bpd bsw 50.3% production index 0.7 stb/d/psi tos na matrix acidizing design data 𝑋𝐻𝐹 0.08 𝛽𝐻𝐹 0.21 𝑋15% 𝐻𝐶𝐿 0.35 𝛽𝐻𝐶𝐿 0.12 economic evaluation capex opex net profit value 2 years royalty 10% oil price 70 usd per barrel 2.1. description and interpretation of the different graph’s obtained before and after acidification the well profile is illustrated in fig. 1. the well production condition over the years are concerned with the pressure transient over times was recorded and a nodal analysis performed to corroborate the drop in production rate, with pi 0.75 stb/psi/d as shown in fig. 2. k. njeudjang et al. / iraqi journal of chemical and petroleum engineering 23,4 (2022) 1 6 3 fig. 1. well schematic fig. 2. nodal analysis before treatment in fig. 2, the rate is way below the economic objectives of this well set after completion which stood at 1150 bpd and bottom hole pressure 3500 psi. the inflow performance relationship (ipr) represents the oil flowing from reservoir drainage into the well bore area meanwhile vertical lift performance (vlp) represents the oil flowing to surface and the point of intersection stands for the optimal flowing condition of the well with reservoir damage. based on the well log obtained during drilling well x is a high permeability well with more than 20 % feldspar mineral, the heterogeneous nature of our reservoir allows us to envisage the presence of clay and carbonates in small quantities. the acid treatment is scheduled to be a 30:70 % coupled with a diverter to increase downhole treating surface area. a formation opening test is initially performed to ascertain opening pressures and maximum surface pressures, tubing cleaning is performed with 15% hcl acid. the main job treatments: 15% hcl –acidic preflush, vol of hcl =2327 gal; main treatment 13.5:1.5% hcl/hf acid, vol of hf = 6330gal; over flush 5% hcl, vol of 5% = 3554 gal; pumping rate = 4 bpm; and well surface pressure = 1632psi. nevertheless, haven carried out laboratory analysis and simulation, once on the field. the formation is said to be tide, since we could only execute this job at an average 2.2 bpm and pumping intermittently as shown in fig. 3. however, all treatment volumes are successfully injected. the pumping schedule obtained from ifs (30:70 %) sequence of every fluid was respected. though with longer treatment hours due to the formation tideness. fluid volume are pumped accordingly and at the end of this treatment a tubing volume is considered to spot all treatment fluids into the formation as shown in fig. 4. fig. 3. live well parameters k. njeudjang et al. / iraqi journal of chemical and petroleum engineering 23,4 (2022) 1 6 4 fig. 4. pumping stages this is the pressure transient test performed after the treatment. the bottom hole pressure here is given by the reservoir pressure minus the draw down pressure given by horner’s formula (see table 2 and fig. 5). table 2. build–up test data recorded after treatment reservoir pressure (pwf)(psi) bottom hole pressure (pi-pwf)(psi) horner’s time (dt+tp)/tp 3075 425 0.00597314 3125 375 0.01091003 3150 350 0.01474476 3175 325 0.01992734 3200 300 0.02693152 3225 275 0.03639758 3250 250 0.04919082 3275 225 0.06648071 3300 200 0.08984776 3325 175 0.12142801 3350 150 0.16410827 3400 100 0.29974617 3450 50 0.54749079 3500 0 1 fig. 5. build – up test graph after treatment this analysis carried out after stimulation, optimal production rate of oil at our point of intersection stands at 850 bpd, bottom hole pressure 3076 psi as shown in fig. 6. this rate approaches us closer to the initial reservoir production condition just after drilling thus keeping us not to far from the well initial objectives. fig. 6. nodal analysis after treatment 2.2. economical evaluation the matrix acid method execution and production profile of the well x is obtained by simulation with the help of ifsand pipesim software which constituted the first parts and the second consisted of carrying out an economic evaluation and to estimate gains to be generated by the company should this project be executed with this degree of success. to this effect consideration are made on the capital expenditures (capex), operating expenditures (opex) and the discount rate as shown in k. njeudjang et al. / iraqi journal of chemical and petroleum engineering 23,4 (2022) 1 6 5 table 3. the simulated results are 2 years for the return on investment. table 3. equipment well data: capex, opex and profit capex opex oil market equipment rentals, chemicals used 720,000 usd platform intergrity, pump hours, accommodation 250,000usd selling price for a barrel of crude oil : 70 usd cost of producing a barrel of oil :10$ oil daily price taxes is 10% discount rate : 20% the revenue generated is based solely on oil produced from the well, the oil production rate per day for this well stands at 850 bpd, the company is said to pay taxes representing 10% of the revenue generated per year, with oil price at 70usd per barrel. table 4 shows profit generated without taxes deducted. table 4. oil production profit well type stb/d stb/year per year ($) oil production 850 310,250 21.717.500 haven subtracted the expenses from our income generated; we deduced how much profit was generated by the company during this period. let’s note that matrix acid stimulation is successful and oil production following our nodal analysis is said to be stable for a period of 2 years. the net present value (npv) which represents the company return on investment given by npv = gross oil – (total cost+ discount rate). the results of its operation are highlighted in table 5. table 5. company npv for the next two years total cost= (capex + opex + taxes ) usd profit oil (usd) npv (usd) 5,313,500 43.435.000 29,434,500 cost of oil = 10usd * 850bpd * 365 * 2 = 6, 205,000 usd; profit oil (gross oil) = 850bpd * 70 usd/b * 365 * 2 = 43,435,000 usd; taxes = 10% * profit oil = 4,343,500 usd; total cost = capex + opex + taxes = 5,313,500 usd; discount rate = 20% * gross oil = 8,687.000 usd; npv = gross oil – (total cost + discount rate) = 43,435,000 usd – (5, 313,500 usd + 8,687.000 usd) = 21,699,500 usd. the return on investment is the ratio between net income and investment, it’s equally another economic criteria used to determine the profitability of the project: roi = npv / total cost (without taxes) = 29,434,500/ 970,000usd = 30.3. the economic results show a strong positive npv and a good roi though with oil price fixed at 70usd/barrel. the choice of production enhance is said to yield profit because it increases the percentage of oil recuperated with minimal cost on investment. coupled with a possible increase in oil prices this methods remains the best alternative. the payback period (pbp) refers to the amount of time it takes to recover the cost of an investment, that’s the length of time an investment reaches a break-even point. the data and procedure necessary to accomplish this calculation is given by: the total cost to carry out a matrix acid stimulation job; the cost of a barrel of oil per day (taxes inclusive = 10%) of total oil production; and oil price standing at 70 usd/stb. this is therefore given by: pbp = total cost (usd) / daily oil price (usd/d) as shown in table 6. table 6. company payback period total cost= (capex + opex + taxes ) usd oil prices (usd/stb) daily oil sales pbp days 5,313,500 70 59,500 90 days thus, after 90 days of production we start making profit from the investment, however let’s not that, this matrix acidizing treatment is said to sustain the permeability of 50 md and a skin of -1.5 for a period of two years, with this in mind we remain even more profitable should oil prices increase. 3conclusion sandstone-acidizing treatments were successfully performed in the field y and encouraging results were obtained on well x. this study aimed to show case to matrix acidizing candidate selection; acid stimulation execution; and economic evaluation for a successful stimulation jobs. considering the data obtained during mud logging, the different assumptions about the fluid and rock compositions, can be ascertain. the injection of 13.5:1.5% hcl/hf acid solution results in dissolution of calcite, clays and feldspar minerals. however, reservoir porosity and permeability can be enhanced in a region extending several meters around the injection well (further studies can be carried out to ascertain this). nevertheless, the high reactivity of the acid coupled with downhole temperatures of 200°f and a weak flow prevented the penetration of acid. this high reactivity also involves the risk of creating wormholes, able to increase the porosity but not always the permeability of the fractured reservoir, reasons why an over flush was performed. this technique is considered risky, due to the secondary and tertiary reactions between the spent acid and the rock. precipitates form resulting from these reactions can be deposit in the pores and fractures of the rock and eventually negate the positive impact of the primary reaction. surface pressure drops on the graph revealed that the treatment has touch the perforation. consequently, being able to assess the extent of the secondary and tertiary reactions under reservoir conditions is therefore critical for the acid treatment success, during this job the acid reaction time was reduce to bear minimal (time to recommence the gas lift system of the well). horner’s equation was used on the plot of reservoir pressure over time, the slope of (m) was used to obtain the new skin and verify the permeability, and with these new set of reservoir properties a simulation performed in pipesim software could gave the following: production index = 2; production rate = 845bpd; skin = 1.5; and permeability = 50. the reservoir heterogeneity did not facilitate the smooth modelling of the treatment k. njeudjang et al. / iraqi journal of chemical and petroleum engineering 23,4 (2022) 1 6 6 proposed, because we lack accurate data on the initial reservoir petrophysical properties, however the economic evaluation carried out showed the following: discount rate = 20% * gross oil = 8,687.000 usd; net present value = gross oil – (total cost + discount rate) = 21,699,500 usd; return on investment = 30.3; and payback period = 90 days. references [1] r. john and l. richard, introduction to petroleum engineering. wiley, new jersey (2017). [2] m. economides and d. hill, petroleum production systems, 2nd ed. westford: prentice-hall (2013). [3] l. dake, fundamentals of reservoir engineering, elsevier, amsterdam (1978). [4] r, s. schechter, oil well stimulation, prentice hall, englewood cliffs-nj (1992). [5] r.s. schechter and j.l. gidley, the change in pore size distributions from surface reactions in porous media. aiche j, 339 (1969). [6] m. davorin, sand control in well construction and operation, springer (2012). [7] h. fogler and c. mccune, predicting the flow and reaction of hci / hf mixtures in porous sandstone cores. spej, 248 (1976). [8] s.l. bryant, an improved model of mud acid / sandstone chemistry, spe paper, 22855 (1991). [9] i. bergman, the long-term dissolution of silica powders in dilute hydrofluoric acid, appl. chem. 3, 356 (1963). [10] s. l. bryant, an improved model of mud acid / sandstone chemistry, spe paper, 22855 (1991). [11] m.j. economides, petroleum production system ch13 and 14, prentice hall ptr, new jersey (2002). [12] m. p. d. aurianto, d. t. maulana and s. chandra, evaluation of successful matrix acidizing method in a geothermal well with comparative sensitivity of acid fluid models, volume, and concentration: a case study on well “x”, iop conf. ser.: earth environ. sci. 1014, 012015 (2022). [13] c. w. crowe and s. s. minor, effect of corrosion inhibitors on matrix stimulation results, jpt, 1853 (1985). [14] e. p. motta, matrix acidizing of horizontal wells. published ph.d, dissertation, university of texas at austin (1993). [15] d. brannon and p. grimmer, matrix acidizing design and quality-control techniques prove successful in main pass area sandstone, jpt, 931 (1987). [16] c.n. fredd and h.s. fogler, alternative stimulation fluids and their impact on carbonate acidizing, in proceedings of the spe formation damage control symposium, lafayette, la, usa (1996). [17] o. gomez chacon and m. pournik, matrix acidizing in carbonate formations, processes 10, 174 (2022). [18] s. pal, m. mushtaq, f. banat, a.m. al sumaiti, review of surfactant-assisted chemical enhanced oil recovery for carbonate reservoirs: challenges and future perspectives. pet. sci. 15, 77 (2018). [19] m. prasetya dwi aurianto, d. taha maulana and s. chandra, evaluation of successful matrix acidizing method in a geothermal well with comparative sensitivity of acid fluid models, volume, and concentration: a case study on well “x”, iop conf. ser.: earth environ. sci. 1014, 012015 (2022). [20] z. rahim, h. al-anazi, mahbub ahmed, a. alkanaan and w. el-mofty, matrix acidizing innovation surpasses competing methods in saudi carbonate, j. pet. technol. 66, 32 (2014). [21] g. zimmermann, g. blöcher, a. reinicke and w. brandt, rock specific hydraulic fracturing and matrix acidizing to enhance a geothermal system – concepts and field results, tectonophysics 503, 146 (2011). [22] t.w. teklu, h.h. abass, r. hanashmooni, j.c. carratu and m. ermila, experimental investigation of acid imbibition on matrix and fractured carbonate rich shales, j. natural gas sci. eng. 45, 706 (2017). https://books.google.iq/books?hl=en&lr=&id=dbipdqaaqbaj&oi=fnd&pg=pp13&dq=%5b1%5d%09r.+john+and+l.+richard,+introduction+to+petroleum+engineering.+wiley,+new+jersey+(2017).&ots=ahagjjzkjl&sig=pvhbpezshtmu_6axuv2_lxxr8fk&redir_esc=y#v=onepage&q=%5b1%5d%09r.%20john%20and%20l.%20richard%2c%20introduction%20to%20petroleum%20engineering.%20wiley%2c%20new%20jersey%20(2017).&f=false https://books.google.iq/books?hl=en&lr=&id=dbipdqaaqbaj&oi=fnd&pg=pp13&dq=%5b1%5d%09r.+john+and+l.+richard,+introduction+to+petroleum+engineering.+wiley,+new+jersey+(2017).&ots=ahagjjzkjl&sig=pvhbpezshtmu_6axuv2_lxxr8fk&redir_esc=y#v=onepage&q=%5b1%5d%09r.%20john%20and%20l.%20richard%2c%20introduction%20to%20petroleum%20engineering.%20wiley%2c%20new%20jersey%20(2017).&f=false https://aiche.onlinelibrary.wiley.com/doi/abs/10.1002/aic.690150309 https://aiche.onlinelibrary.wiley.com/doi/abs/10.1002/aic.690150309 https://aiche.onlinelibrary.wiley.com/doi/abs/10.1002/aic.690150309 https://books.google.iq/books?hl=en&lr=&id=oojd8vlzxnmc&oi=fnd&pg=pr5&dq=%5b6%5d%09m.+davorin,+sand+control+in+well+construction+and+operation,+springer+(2012).+&ots=sazmunyjvc&sig=n3zazfzbbxiq2pgw0kigwpvy9r8&redir_esc=y#v=onepage&q=%5b6%5d%09m.%20davorin%2c%20sand%20control%20in%20well%20construction%20and%20operation%2c%20springer%20(2012).&f=false https://books.google.iq/books?hl=en&lr=&id=oojd8vlzxnmc&oi=fnd&pg=pr5&dq=%5b6%5d%09m.+davorin,+sand+control+in+well+construction+and+operation,+springer+(2012).+&ots=sazmunyjvc&sig=n3zazfzbbxiq2pgw0kigwpvy9r8&redir_esc=y#v=onepage&q=%5b6%5d%09m.%20davorin%2c%20sand%20control%20in%20well%20construction%20and%20operation%2c%20springer%20(2012).&f=false 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https://www.sciencedirect.com/science/article/abs/pii/s1875510017302470 https://www.sciencedirect.com/science/article/abs/pii/s1875510017302470 iraqi journal of chemical and petroleum engineering vol.14 no.2 (june 2013) 2939 issn: 1997-4884 studying the factors affecting the drag coefficient in nonnewtonian fluids muhannad a. r. mohammed and dina adil elia halagy chemical engineering department, college of engineering, university of nahrain abstract the aim of this research is to study the factors affecting drag coefficient (c d ) in non-newtonian fluids which are the rheological properties ,concentrations of nonnewtonian fluids, particle shape, size and the density difference between particle and fluid .also this study shows drag coefficient (c d ) and particle reynolds' number (re p ) relationship and the effect of rheological properties on this relationship. an experimental apparatus was designed and built, which consists of perspex pipe of length of 160 cm. and inside diameter of 7.8 cm. to calculate the settling velocity, also electronic circuit was designed to calculate the falling time of particles through fluid. two types of solid particles were used; glass spheres and crushed rocks as irregularly shaped particles with different diameters and compared with each other. the concept of equivalent spherical diameter (d s ) was used to calculate the diameters of irregularly shaped particles. the flow behavior for non-newtonian fluids was represented by power-law model. two types of polymers were used, carboxy methyl cellulose cmc with concentrations of (3.71, 5, 15 and 17.5) g/l and polyacrylamide with concentrations of (2, 4 and 6) g/l. the results showed that the drag coefficient decreased with increasing settling velocity and particle diameters and sizes; and increased as fluid become far from newtonian behavior and concentrations and the density difference between particle and fluid. the results also showed that the rheological properties of non-newtonian fluids have a great effect on the drag coefficient and particle reynolds number relationship, especially in laminar-slip regime and decreases or vanishes at transition and turbulentslip regimes. new correlations were obtained which relates drag coefficient with concentrations of polymers and with flow behavior indices for spherical and irregular shaped particles in carboxy methyl cellulose cmc and polyacrylamide solutions. keywords: fluid flow, drag, settling. introduction it has been shown theoretically and experimentally that the resisting force acting on a body moving in a fluid depends on particle’s shape, size, projected area, the relative velocity of iraqi journal of chemical and petroleum engineering university of baghdad college of engineering studying the factors affecting the drag coefficient in non-newtonian fluids 30 ijcpe vol.14 no.2 (june 2013) -available online at: www.iasj.net the body, and on the density and viscosity of the fluid [1]. the terminal settling velocity is the most important factor, which affecting relationship between the drag coefficient and particle reynolds’ number, since it is involving in the evaluation of these two quantities [2]. in 1959, becker [3] stated that the drag on oriented bodies (or particles) in motion through an infinite fluid is composed of a viscous drag and an inertial drag, in which a quadratic drag formula was adopted. this drag is related to the fluid velocity and to properties of the fluid and the particle. according to that drag is related to particle reynolds' number. the first attempt is made by slattery and bird in 1961 [4], to understand the behavior of non-newtonian fluid around particles. they used ellis rheological model in their study, and they measured the drag coefficient of spheres moving through cmc solutions. two dimensionless correlations for drag coefficient in terms of a modified particle reynolds’ number based on ellis parameters, have been adopted. the first study on a modified c d -re p relationship for sphere in bingham plastic non-newtonian fluid is conducted by valentick and whitmore [5] in 1965. they used a flocculated aqueous clay suspension of six densities with different flow parameters. these suspensions follow bingham plastic model. they stated that the drag forces of a particle moving in bingham fluid are composed of force of falling in newtonian fluid and a force to overcome the yield stress of bingham plastic. particle dynamics the movement of a particle through a fluid requires external force acting on a particle. this force may come from a density difference between the particle and the fluid or may be the result of electric or magnetic fields. three forces act on a particle moving through a stagnant fluid: the gravitational (f g ), the buoyant force (f b ) which acts parallel with the external force but in opposite direction and the drag force (f d ) which appears whenever there is relative motion between the particle and the fluid. the drag force acts to oppose the motion and acts parallel with direction of movement but in opposite direction, as shown in figure 1 [6, 7]. drag coefficient may be calculated from: c d = 3 4 2 )( sf fps v d    g ... (1) fig. 1 a free falling particle under the action of gravity [3] particle reynolds’ number, re p particle reynolds’ number is used to indicate whether the boundary layer around a particle is turbulent or laminar, and the drag exerted will depended on this. it is a measure of the relative important of inertial to viscous forces of flow [8], and is given by their ratio by following formula: re p =   psf dv ... (2) muhannad a. r. mohammed and dina adil elia halagy -available online at: www.iasj.net ijcpe vol.14 no.2 (june 2013) 31 for newtonian fluid, viscosity μ is constant independent of shear rate and the concept settling shear rate is not used [2]. for non-newtonian fluid the viscosity varies with the shear rate. therefore, an expression of equivalent viscosity eq can be used, which represent the viscosity of fluid around the particle during its movement. the equivalent viscosity is defined as the ratio of shear stress on particle surface to average shear rate of the particle [2]. p p eq .    8478 ... (3) there are several equations that relate shear stress to shear rate for nonnewtonian fluids. according to that, there are several forms of equivalent viscosities depending on the type of the nonnewtonian model. in this study powerlaw model's equation is only used and the equivalent viscosity of this model as follows [2]: …(4) experimental apparatus and materials an experimental apparatus has been designed and built to measure the terminal settling velocity for solid particles so drag coefficient and particle reynolds’ number can be calculated. the test apparatus is consisting of vertical and transparent perspex pipe, with length of 160 cm, outside diameter of 8 cm and inside diameter of 7.8 cm to avoid wall effects as shown in figure (2) below. for careful determination of terminal settling velocity the pipe was divided into four sections as follows; 1. first section is inlet section l1. it is used for acceleration which defined as the distance that particle should travel before reaching an equilibrium of forces to get constant velocity (settling velocity). the first section must have sufficient settling length for accurate timing, so the inlet length used in this work was 85 cm. 2. second section is test section l2. it is used for calculating the terminal settling velocity. the length was 50 cm, this section divided into two sections each of them 25 cm. 3. the third section is drainage section l3. it is used for draining the fluid and avoids end effects fig. 2, schematic diagram for experimental apparatus electrical circuit the precision of measurement of the velocity is directly related to the time taken by the particle to travel a known distance (after travel l1). aiming to assure the precision of the time measurement and to eliminate the human error, a digital electronic circuit was designed with three photo-sensor nets; these three nets are measured the time of particle falling in test section through fluid. the transmitter transmits an infera-red ray to five receivers, when particle fell down through the column and reaches studying the factors affecting the drag coefficient in non-newtonian fluids 32 ijcpe vol.14 no.2 (june 2013) -available online at: www.iasj.net distance of 85 cm the ray will disconnect. the designs of the counter’s circuit, transmitters and receivers are shown in figs. 3a, 3b and 4. fig. 3a, design of counter’s circuit fig. 3b, design of counter’s circuit fig. 4, the design of the transmitter test fluids in order to get different rheological properties two polymers were used, carboxy methyl cellulose cmc and polyacrylamide (water soluble polymers) with different concentrations as non-newtonian fluids and water as newtonian fluid. seven different concentrations were prepared, four for cmc and three for polyacrylamide, these values are given in table (1). the densities of each test fluids used in this experimental work have been measured by pyknometer of volume 25 ml. the density of all polymer solutions prepared found to be 1 gm. /cc. power-law model was used to represent the flow behavior of nonnewtonian fluids. the rheological properties (n, k) of each nonnewtonian fluid used for settling velocity determinations were measured by fann vg meter model 35a rotational coaxial cylinder type the parameters n and k can be determined approximately using a fann-vg reading as follow; n=3.32log 300 600 θ θ k=   n1022 600 where; 600θ =dial reading at 600 rpm, and; 300θ = dial reading at 300 rpm particle diameter's measurements a. sphere particles spherical particles are made of glass with different diameters; the diameters were measured by a vernier with an accuracy of 0.01 mm. the weight of particles was measured by a digital balance and the volume was calculated using vol. = 3 6 s d , while the area = 2 4 s d muhannad a. r. mohammed and dina adil elia halagy -available online at: www.iasj.net ijcpe vol.14 no.2 (june 2013) 33 then, the density of the particle is the ratio of its weight to its volume; the physical characteristics of spherical particles are given in table 2. b. irregular shaped particles the irregular shaped particles are formed from crushed rocks. the problem with these particles that they do not have standard diameters, so the concept of the equivalent spherical diameter d s was used, which represented the diameter has a volume of sphere. the volume of irregular shaped particles had been measured by displacement method using kerosene; physical characteristics of irregular particles are given in table 3. table 1, concentrations of polymers and power-law constants no. polymer concentration, g./l power-law constants 1 cmc 3.71 n=0.73,k=0.015 2 cmc 5 n=0.71,k=0.091 3 cmc 15 n=0.63,k=0.287 4 cmc 17.5 n=0.61,k=0.566 5 polyacr. 2 n=0.58,k=1.016 6 polyacr. 4 n=0.51,k=1.135 7 polyacr. 6 n=0.39,k=3.320 table 2, physical characteristics of spherical particles d s ,cm. mass, g. v p , cm 3 p  , g./cm 3 a p , cm 2 0.22 0.014 0.0055 2.545 0.038 0.3 0.034 0.0141 2.411 0.071 0.4 0.082 0.033 2.484 0.126 0.6 0.299 0.113 2.646 0.283 0.8 0.675 0.268 2.518 0.503 1 1.338 0.524 2.553 0.785 1.43 3.825 1.531 2.498 1.606 2 10.841 4.189 2.588 3.141 table 3, physical characteristics of irregular shaped particles d s ,cm. mass, g. v p , cm 3 p  , gr./cm 3 a p , cm 2 0.984 0.970 0.5 1.940 0.762 1.102 1.554 0.7 2.220 0.954 1.152 1.862 0.8 2.327 1.042 1.198 1.936 0.9 2.151 1.127 1.241 2.735 1 2.735 1.209 1.388 3.042 1.4 2.173 1.513 1.420 2.719 1.5 1.813 1.584 1.563 4.791 2 2.395 1.919 1.789 8.391 3 2.797 2.514 1.823 7.104 3.2 2.220 2.610 1.847 8.358 3.3 2.533 2.679 2.121 10.640 5 2.128 3.536 procedure of experimental work the shape of the particles has not been measured in this study. in order to get accurate results, great attention must be paid to each of the followings: 1. firstly, all the used particles were washed in water and dried in oven, in order to avoid the error reading from dirty particles. 2. the temperature of the fluid was recorded of each run by a thermometer. the temperature remained at a room temperature (27-28 c) therefore the fluid properties remained constant throughout the experiment. 3. the pipe was set exactly vertical by using a balance with a bubble, when the bubble in the center of the balance, that means, the pipe is in a vertical position. 4. 7 liters of each fluid was prepared in batches by shaker or mixer adding the necessary amounts of polymer in water. 5. after the test fluid prepared and the pipe was filled with a test fluid, a single particle was introduced into the top of the pipe. the particle should place in the center of the pipe just below the surface of the test fluid and leave it to settle freely. studying the factors affecting the drag coefficient in non-newtonian fluids 34 ijcpe vol.14 no.2 (june 2013) -available online at: www.iasj.net 6. the first inlet section l1 was neglected in order to ensure that the acceleration of particle is ended. when the particle crossed the test sections of l2, l3 the variation in signal will produce in each photosensor net as explained previously and the number of counts will appear in 7-segments displays in the board for each net, then the number of counts changed to time by multiplying with counters’ factor, so the time required for falling particle in each sections l2, l3 will be known. 7. all particles dropped in same way and number of counts recorded. the falling times for each particle in test section (l2 and l3) were measured. 8. the terminal settling velocity of the particle is the measure of the total times along l2 and l3 that the particle required to settle through a known distance of 50 cm, which represented the total test section. v s =50 /t 9. the time of falling of small spherical particles (0.2, 0.3) cm. was recorded manually by digital stop watch with accuracy of 0.01 sec. along test section of 50 cm, because the photo sensor nets were not sufficiently sensitive to record the passing of these particles. 10. the orientation of each falling particles were observed, to show the difference between the falling of spherical particles and irregular shaped particles. 11. then the test fluid was drained by the valve in iron base and particles were released by the second valve at the end of cone, in order to pump another solution and repeat the measurements, and so on. 12. to minimize the error, each experiment repeated 3-4 times. an average time was used, thus average settling velocity was taken. 13. the effect of pipe wall on settling velocity was avoided by taking the ratio of particle diameter to pipe diameter less than or equals to 0.25. results and discussion the values of drag coefficient are high at low values of reynolds' number, and as reynolds' number increased the drag coefficient will decrease, due to fact that the viscous forces are dominated in laminar-slip regime. when this region is ended the transition-slip regime is started, the effect of reynolds’ number on drag coefficient is decreased, until the turbulent-slip regime is started and the drag coefficient will be constant value due to the fact that the inertial forces are dominate in this region and viscous forces will have a small effect. for this reason, the increase in reynolds’ number will not decrease the drag coefficient. it is obvious from figure (5) that as flow behavior index (n) decreased from unity the drag coefficient will increase for the same particle reynolds’ number re p , because the particle will settle at lower velocity; and this effect is greatly realized at low values of reynolds’ number. factors affect drag coefficient 1. settling velocity as the settling velocity of the particles increased the drag coefficient will decrease, because as the velocity increased the drag force exerted by fluid on the particle will be decreased so the drag coefficient will decrease, for spherical and irregular particles, as shown in figure (6). 2. particle diameter the concept of equivalent sphere diameter has been used to calculate the diameter of irregular shaped particles. as the particle diameter increased the muhannad a. r. mohammed and dina adil elia halagy -available online at: www.iasj.net ijcpe vol.14 no.2 (june 2013) 35 drag coefficient will be decreased. due to that as the particle diameter increases the velocity of particle will increase, since the drag force exerted on particle will be decreased, so the drag coefficient decreases. this is shown in figures (7). 3. difference between particle and fluid densities as the difference between particle and fluid density (ρ p ρ f ) increased the drag coefficient will increase. this is shown in figure 8. 4. concentration to show the effect of concentration of polymers (carboxy methyl cellulose cmc, polyacrylamide) on drag coefficient, graphs are plotted for particles settling in carboxy methyl cellulose cmc solution with concentrations of (3.71, 5, 15, 17.5) g./l and polyacrylamide solution with concentrations of (2, 4, 6) g./l for spheres and irregular shaped particles. as concentration increased, the viscosity of fluid will increase and settling velocity will decrease, so the drag coefficient increases for all diameters of particles used, as shown in figure 9. 5. rheological properties the relationships between flow behaviour indices and drag coefficient with particle diameters for both spherical and irregular shaped particles had been studied. it is clear that as the flow behaviour index increased and approached to unity the drag coefficient decreased, due to the increase in the settling velocity of particles, for all diameters of particles which have been used. this is shown in figure 10. empirical equations for drag coefficient 1. a general formula was obtained for drag coefficient (y) versus carboxy methyl cellulose cmc and polyacrylamide concentrations (x) from our experimental work for spherical particles and irregular shaped particles log y= b log x+a 2. a general formula was obtained for drag coefficient (y) versus flow behavior index (x) from our experimental work for spherical particles and irregular shaped particles log y= b log x+a where a, b are the constants of equation depends on the shape, diameters of particles and flow behavior indices. conclusions 1. as particle reynolds number increased the drag coefficient will decrease especially in laminar-slip regime until the drag coefficient reaches a constant value in turbulent-slip regime. 2. the particle size has a great effect on the drag coefficient, as the particle diameter or volume increased the drag coefficient will decrease since the settling velocity will increase. 3. the rheological properties of nonnewtonian fluids have a great effect on drag coefficient, because as the fluid became far from newtonian behavior, (flow index n far from unity), the drag coefficient will be increased. 4. the difference in density between the particle and fluid affect the drag coefficient, as the difference increases the drag coefficient will increase. the concentrations of polymer fluids have effect on c, it was shown that as the concentration of fluid increased the drag coefficient will increase. studying the factors affecting the drag coefficient in non-newtonian fluids 36 ijcpe vol.14 no.2 (june 2013) -available online at: www.iasj.net nomenclature symbol meaning unit a p projected area of the particle in a plane perpendicular to the direction of the flow. cm 2 c d particle drag coefficient dimensionless d inside pipe diameter cm d p particle diameter cm d s diameter of particle has the same volume as a sphere cm f force dyne f b bouncy force dyne f d drag force dyne f g gravity force dyne g acceleration due to gravity cm/s 2 k power-law consistency index g.s n /100 cm 2 l length cm n power-law flow behavior index dimensionless re p particle reynolds’ number dimensionless v p solid particle volume cm 3 v s settling velocity cm/s greek symbols symbol meaning unit θ 300 , θ 600 dial reading of fann-vg meter rpm, at 300 and 600 rpm respectively degrees μ newtonian fluid viscosity cp μ eq equivalent viscosity cp ρ f density of fluid g/cm 3 ρ p density of particle g/cm 3 references 1. pettyjhon e.s. and cheristiansen e.b. “effect of particle shape on free settling rates of isometric particles”; chem. eng. progress, 44(1948), 2. 2. muhannad a.r. “the effect of particles shape and size and the rheological properties of nonnewtonian fluids on drag coefficient and particle reynold’s number relationship”, ph.d. thesis, (1998). 3. becker h.a. “the effects of shape and reynolds' number on drag in the motion of a freely oriented body in an infinite fluid”, the cand. j. of chem. eng., april, (1959). 4. slattery j.c. and bird r.b. “nonnewtonian flow past a sphere”, chem. eng. science vol.16 (1961). 5. valentik l. and whitmore r.l. “the terminal velocity of spheres in bingham plastic”, brit. j. appl. phys. vol.16 (1965). 6. flemmer r.l.c. and banks c.l “on the drag coefficient of a sphere”, powder tech. 48 (1986). muhannad a. r. mohammed and dina adil elia halagy -available online at: www.iasj.net ijcpe vol.14 no.2 (june 2013) 37 7. michell s. j., “fluid and particle mechanics”, pergamon press ltd., (1970) p. 288301. 8. given on internet by courtney k.harris, “sediment transport processes in coastal environments”, (2003), at a. http://www.vims.edu/~ckharris/ms6 98-03/lecture-2pdf 9. chhabra, r.p. and richardson, " non-newtonian flow in the process industries", elsevier publishing ltd. (1999). 10. fann viscometer, model 35a manual. http://www.expotechusa.com/manu als/fann/35496.pdf 11. flinn scientific inc., "preparation of polyvinyl alcohol" (2003). http://www.flinnsci.com 12. taugbol, k. , fimreite, g. , o.i. , svanes, k., omland, t. h., svela, p. e., and breivik, d .h., "development and field testing of a unique high-temperature/high pressure (hthp) oil-based drilling fluid with minimum rheology and maximum sag stability'', spe 96285, 2005. 13. carbajal, d., burress, c.,shumway, b., and zhang, y., "combining proven anti-sag technologies for hthp north sea applications: clay-free oil-based fluid and synthetic, sub-micron weight material", spe/iadc 119378, 2009 fig. 5, c d -re p relationship at different flow behavior (n) fig. 6, the effect of terminal settling on drag coefficient http://www.expotechusa.com/manuals/fann/35496.pdf http://www.expotechusa.com/manuals/fann/35496.pdf http://www.flinnsci.com/ studying the factors affecting the drag coefficient in non-newtonian fluids 38 ijcpe vol.14 no.2 (june 2013) -available online at: www.iasj.net fig. 7, the effect of particle diameter on drag coefficient fig. 8, the effect of difference in density between the particle and fluid on drag coefficient muhannad a. r. mohammed and dina adil elia halagy -available online at: www.iasj.net ijcpe vol.14 no.2 (june 2013) 39 fig. 9, the effect of cmc and polyacrylamide concentrations on c d for different diameters of spherical and irregular shaped particles fig. 10, the effect of flow index on c d for different diameters of spherical and irregular shaped particles 1.00 10.00 concentration, gr/lit. 0.10 1.00 10.00 100.00 1000.00 c d spheres in polyacrylamide dp=0.8 cm dp=1 cm dp=1.43 cm dp=2 cm 1.00 10.00 100.00 concentration, gr/lit. 0.10 1.00 c d spheres in cmc solutions dp=0.8 cm dp=1 cm dp=1.43 cm dp=2 cm 1.00 10.00 concentration, gr/lit 1.00 10.00 100.00 1000.00 c d irregular shaped in polyacrylamide dp=0.984 cm dp=1.101 cm dp=1.152 cm dp=1.199 cm dp=1.42 cm 1.00 10.00 100.00 concentration, gr/lit. 0.10 1.00 10.00 c d irregular shaped in cmc solutions dp=0.984 cm dp=1.101 cm dp=1.152 cm dp=1.199 cm dp=1.42 cm 0.10 1.00 n 0.10 1.00 10.00 100.00 1000.00 c d spheres dp=0.8 cm dp=1 cm dp=1.43 cm dp=2 cm 0.10 1.00 n 0.10 1.00 10.00 100.00 1000.00 c d irregular shaped dp=0.981 cm dp=1.101 cm dp=1.152 cm dp=1.199 cm dp=1.42 cm available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.23 no.4 (december 2022) 7 – 16 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: usama alameedy, email: usama.sahib@coeng.uobaghdad.edu.iq, name: ayad a. al-haleem, email: dr.ayad.a.h@coeng.uobaghdad.edu.iq, name: abdulameer almalichy, email: almalichy.abdulameer.mohsin.kadhim@student.uni-miskolc.hu ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. well performance following matrix acidizing treatment: case study of the mi4 unit in ahdeb oil field usama alameedya, ayad a. al-haleema , and abdulameer almalichyb a petroleum engineering department-college of engineering-university of baghdad. b petroleum engineering departmentcollege of earth science and engineeringuniversity of miskolc. abstract the productivity of oil wells may be improved by determining the value of enhancing well productivity and the likely reasons or sources of formation damage after the well has been recognized as underperforming. oil well productivity may be improved, but the economics of this gradual improvement may be compromised. it is important to analyze the influence of the skin effect on the recovery of the reserve. the acid treatment evaluated for the well ad-12, primarily for the zone mi4; using a license of stimpro stimulation software to validate the experimental work to the field scale, this software is considered the most comprehensive instrument for planning and monitoring matrix acid treatments and utilizing actual data to provide a far better knowledge of the well's reaction, with methods that represent the reality of what is happening in the reservoir before, during, and after matrix acid treatments, through the post-treatment skin factor, which is the most frequently utilized statistic for analyzing stimulation treatments and relies on the geometry of the wormholed zone. referring to the previous buildup tests for ad-12, the skin value of -3.97 is approximately identical to or slightly larger than the skin value estimated by the acid treatment simulation using stimpro. moreover, when the simulator was performed, the invading fluid revealed two distinct depths of investigation inside the treated zone. while the fluid invasion in the bottom area has invaded deeply at a distance of 95 inches despite the top layer wormhole penetrating to a depth of 32 inches. keywords: mishrif reservoir, skin factor, acid treatment, matrix acidizing, and stimpro. received on 12/06/2022, accepted on 03/08/2022, published on 30/12/2022 https://doi.org/10.31699/ijcpe.2022.4.2 1introduction the term "formation damage" refers to a reduction in the permeability of the original rock as a consequence of some alteration, such as clay swelling, fines migration, particle clogging, or changes in wettability. due to scale precipitation, asphaltene deposition, and other causes, formation damage may also occur throughout the productive or injective life of the well. matrix acidizing treatments restore damage to the formation caused by earlier well operations. the ultimate objective of these treatments is often to restore the original formation's permeability. on the other hand, a matrix acidifying treatment may significantly enhance the formation process in sandstones and shales [1]. the permeability may be considerably improved to values much larger than the initial permeability, up to a distance of possibly tens of feet from the wellbore. consequently, while hydraulic fracturing is usually projected to provide better results in sandstones or shales than matrix acidizing in carbonate rocks, both procedures are competitive [2]. more work is required to determine the most effective option. as described as a technique of well stimulation, matrix acidizing involves introducing an acid solution into the formation to dissolve a few minerals present and, as a result, restore or increase permeability around the wellbore, among other things [1]. due to the low velocity of the acid injection, the pressure is maintained below the formation breakdown pressure, and as a result, the reservoir rock does not fracture. candidate selection and stimulation methods are aided by a decision tree (fig. 1). the productivity achievement determines the stimulation approach [3]. to meet the productivity objective, matrix stimulation should provide a skin effect of 10 % of the initial damage skin effect for sandstones and 2 to 3 % for carbonates. aside from hydraulic fracturing, there is no other stimulation method for sandstone reservoirs. acid fracturing may be cost-effective to boost productivity in carbonate reservoirs (limestones or dolomites). in both circumstances, the reservoir experiences a hydraulic fracture [2]. 2design of the stimulation treatment sequence if the well has been recognized as underperforming, then the monetary value of increasing well productivity and the likely formation damage sources have been evaluated [4]–[7]. the engineer must next identify the corrective action. two nonfracture procedures are utilized to increase oil and gas well productivity. the wellbore is cleaned using chemical and/or mechanical techniques. in http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:usama.sahib@coeng.uobaghdad.edu.iq mailto:dr.ayad.a.h@coeng.uobaghdad.edu.iq mailto:almalichy.abdulameer.mohsin.kadhim@student.uni-miskolc.hu http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2022.4.2 u. alameedy et al. / iraqi journal of chemical and petroleum engineering 23,4 (2022) 7 16 8 order to stimulate the matrix, fluids are pumped into the formation near the wellbore [2]. typically, matrix stimulation treatments administered below fracture pressure via tubing, drillpipe, or coiled tubing consist of a series of fluids, known as stages. a minimum treatment includes a preflush stage with a nondamaging, nonreactive fluid to set an injection rate, a stage of the main treating fluid, and an overflush stage to remove the main treating fluid from the tubing and displace it into the vicinity of the wellbore. other auxiliary steps are used in the majority of therapies to improve their efficacy. the next sections examine the selection of chemicals for the stages and the design of the treatment sequence (pumping schedule). [8]. fig. 1. candidate selection and stimulation methods [2] a) preflush preflushes of hydrochloric acid are used to prepare or condition the formation that will be stimulated so that the acid will be accepted in the most favorable parts. the primary goal of the preflush is to displace the brine from the wellbore to prevent contact between the hydrofluoric acid and the brine of formation, which contains potassium, sodium, and calcium, which causes precipitation [9]. b) main (acid) treatment this stage's goal is to repair the well's damage. the appropriate injection rate is determined by the acidizing task matrix's acidizing or acid fracturing type. in carbonates, wormhole propagation speed increases with injection rate, so a high injection rate is required for rapid wormhole propagation. when acidizing in areas of highwater saturation, low pump rates are also advised. the maximum permitted pressure for the tubing, the surface equipment, and the pump must be considered to determine whether the formation can withstand larger forces [2]. c) postflush (overflush) the overflush moves the primary acid flush at least four feet away from the wellbore. since retarded acid's reaction time on creation is longer than its injection period, it might aid in acid penetration. instead of using potassium chloride as a post flush in acidizing sandstone formations with hydrofluoric acid, ammonium chloride, nh4cl, is advised [1]. 3monitoring the performance of acidizing treatment the post-treatment skin factor is the most often utilized statistic for analyzing stimulation treatments. in matrix acidizing processes in carbonates, the skin factor relies on the geometry of the wormholed zone. analyzing the injection rate and pressure during injection is recommended for monitoring a matrix acidizing treatment in a carbonate reservoir, in the same way as monitoring a sandstone acidizing treatment is advised [1]. in carbonates, the pressure loss across the wormhole zone is assumed to be insignificant, which means that the wormhole impact on the wellbore skin effect is equivalent to extending the wellbore [10]. the skin's evolution after a carbonate matrix acidizing treatment may be anticipated using wormhole propagation models under this assumption. as the wormhole penetration radius increases in a damaged well with a permeability k, the skin effect is proportional to the wormhole penetration radius as follow: 𝑠 = 𝑘 𝑘𝑠 𝑙𝑛⁡ 𝑟𝑠 𝑟𝑤ℎ − 𝑙𝑛⁡ 𝑟𝑠 𝑟𝑤 (1) as long as the radius of wormhole penetration is greater than the radius of damage, eq. (1) remains valid. alternatively, if the well was initially undamaged or if the wormhole radius was higher than the original damage radius, the skin effect during acidification is assumed to be infinite, and the following eq. (1) is used to represent this: 𝑠 = −𝑙𝑛⁡ 𝑟𝑤ℎ 𝑟𝑤 (2) eqs. (1) and (2), which assume that the injection rate is kept constant during the treatment for the damaged zone, are used to determine the skin impact expected by the volumetric model during the injection, 𝑠 = − 𝑘 2𝑘𝑠 𝑙𝑛⁡[( 𝑟𝑤 𝑟𝑠 ) 2 + 𝑉 𝑃𝑉𝑏𝑡𝜋𝑟𝑠 2𝜙ℎ ] − 𝑙𝑛⁡ 𝑟𝑠 𝑟𝑤 (3) furthermore, since wormholes that penetrate beyond the affected zone or there is no damage, 𝑠 = − 1 2 𝑙𝑛⁡[1 + 𝑉 𝑃𝑉𝑏𝑡𝜋𝑟𝑠 2𝜙ℎ ] (4) both buijse-glasbergen and furui models are used to calculate the radius of the wormhole region for discrete u. alameedy et al. / iraqi journal of chemical and petroleum engineering 23,4 (2022) 7 16 9 injection times. the skin factor is calculated using equation 1or eq. (2) for each rwh obtained using these models. 4max. δp, max.-rate-procedure by paccaloni the [11] approach estimates a steady-state skin effect in accordance with darcy's law to keep track of the development of stimulation treatments. the two most important components of paccaloni's maximum δp, maximum-rate technique is: 1. the largest pwf achievable without breaking the formation should be achieved by injecting the acid at the maximum pace possible. 2. treatments should be evaluated in real-time to ensure the maximum rate aim is fulfilled and detect when enough acid is injected into the formation. 𝑠 = 0.00708𝑘ℎ𝛥𝑝 𝜇𝑞𝑖 − 𝑙𝑛⁡ 𝑟𝑠 𝑟𝑤 (5) where k denotes the formation's permeability, h indicates the thickness of the pay zone, rw represents the wellbore radius, and rs defines the radius impacted by acid injection. typical oilfield units for all of the variables. fig. 2 depicts the treatment of the matrix stimulation design chart. acid injection rate (qi) and pressure drop δp are linked to skin variables in eq. (5). wang et. al. [12] builds a pti vs. qi graph using skin factor as a parameter to track a stimulation treatment. a series of parallel lines with varying skin factor values can be seen on the chart, as long as the skin factor is assumed to be the only variable under consideration. the wellhead pressure and injection rate indicate the treatment, and the skin effect may be seen on the chart. this chart also shows the relationship between fracture pressure and injection rate, keeping the rate as high as feasible without breaking the formation. fig. 2. treatment of the matrix stimulation design chart [13] according to prouvost and economides [14] and validated by paccaloni and tambini [13], it is possible to overstate the skin impact using the paccaloni approach since it neglects transient flow effects. when the pace of change is sudden, this miscalculation might be catastrophic. however, it's not a big problem for most treatments since the inaccuracy is pretty constant, and the development of the skin impact is more essential than its absolute value itself. prouvost and economides [14] developed a method for precisely calculating the changing skin effect during matrix acidization. a thorough posttreatment analysis might benefit from using this method if a defined injection schedule is available. this approach is considered to be among the most helpful design strategies because of the following advantages: • it is possible to evaluate the degree of formation damage using an injection test. • it is likely to estimate the pumping parameters at starting an acidizing matrix process. • can determine if acid amounts utilized are insufficient, appropriate, or excessive. • at the well site, it is possible to make an informed and timely choice, increasing the likelihood of success. 5stimpro stimulation software the stimpro system is intended to give the most complete tools for the planning and analysis of matrix acid treatment. stimpro's matrix acid simulator, on the other hand, focuses on the practical use of real treatment data. the utilization of actual data provides a far better knowledge of the well's reaction, with methods that represent the reality of what is happening in the reservoir before, during, and after matrix acid treatments (fig. 3). operation modes on the main screen include design and analysis of matrix acid treatment, as well as reservoir modelling. acidizing design mode, acidizing analysis mode, and production analysis mode are the three options available to users[15]. fig. 3. stimpro's capabilities [15] a. acidizing design mode using the acidizing design option, a treatment schedule can be generated rapidly and effectively. stimpro will develop a pumping schedule after assisting in the selection of the proper fluids and acids for the u. alameedy et al. / iraqi journal of chemical and petroleum engineering 23,4 (2022) 7 16 10 reservoir's damage. the reservoir penetration may also be specified in this mode. b. acidizing analysis mode pre-treatment design and real-time data analysis are the main priorities of the acidizing analysis mode. the realdata analysis may be done in real-time or post-job, using treatment data that has already been gathered before the project started. c. production analysis mode wells with or without matrix acid treatments may have their production behavior predicted or matched using the production analysis option. using this method, stimpro feeds a reservoir simulator with the acid concentration profile it generated using its hydraulic fracture propagation and acid transport models. this is a critical step in establishing the efficacy of previous treatments and the related economics of future ones. 6results and discussion in stimpro software's acidization model, sandstones and carbonates respond differently to acidizing, which is taken into account. as a result of acidizing, new channels (wormholes) are formed in carbonates, bypassing damage to the wellbore and allowing water to flow into the well. as an alternative to developing new pore channels, acidizing sandstone displaces the particles that block the existing channels. acid tends to migrate in a front around the wellbore in sandstone reservoirs. the kinetics of dissolution in sandstones is surface-reaction restricted, which accounts for a major part of the variance in behavior. carbonates, on the other hand, have a considerably more unstable process. hcl and hf acid are often used in sandstone treatment to reopen and expand pore channels obstructed by clays and siliceous fines. in order to prevent the clays from extracting protons from hf, hcl dissolves any carbonates in the matrix, and hf dissolves slow and fastreacting silicates and carbonates. the ability to calculate the optimal acid treatment volumes and concentrations is typically a determining factor in treatment efficacy. the precipitation of amorphous silica may occur as a consequence of secondary reactions from spent acid rather than decreasing the skin's appearance. there are times when excessively powerful acids might weaken and destabilize formation faces. engineers may use the acidizing design mode to rapidly and effectively develop a treatment program depending on the requirements of the reservoir. stimpro will build a pumping schedule after selecting the proper fluids and acids for the reservoir damage type. it will then be able to indicate the desired reservoir penetration. the order in which the fluid patches are administered and their exact time of application are essential factors for designing a stimulation treatment. after the technique of major acid injection, the pre-and post-flushing phases are the most prevalent components of a treatment sequence. it was decided to do the acidizing job on dec. 2nd, 2011, for the well ad-12 targeting the mishrif reservoir, particularly the mi4 unit, to remove drilling and completion mud damage to the pay zone and improve the performance of the formation by enhancing the permeability; consequently, boost oil production. the whole matrix acidizing job, including the data necessary for operation and the outcomes in a summary report, is clearly shown in fig. 4. the acid job began with a preinjection of water. pump pressure: 12.35-16.90 mpa (1791-2451 psi); pump flow rate: 0.35 m3/min (2.94 bbl/min); total pre-injected water volume: 2 m3 (16.78 bbl). followed by the first injection of acid fluid with pump pressure was 14.48-17.40 mpa (2100-2523 psi), pump rate was 0.38-0.42 m3/min (3.19-3.522 bbl/min), and total acid pumped was 20 m3. the last step was flushed with new water thereafter, by pump pressure: 12.00-13.00 mpa (1740-1885 psi); pump flow rate: 0.570.59 m3/min (4.78-4.95 bbl/min); total volume pumped: 17 m3 (142.5 bbl). in the following scenario, an acidizing carbonate treatment is investigated with stimpro to illustrate pressure matching of measured and simulated data, skin evolution assessment, and a general analysis of an acidizing carbonate treatment. to begin, create a new file to enter the details such as the well survey, fluid type and specifications, and treatment schedule. examine all inputs by clicking the next button to go through the various options. a vertical well ad-12 with perforated casing completion has a total depth of 3169.37 m from where the acid operation was pumped into the perforation depths (2798.0-2808.0) m and (2808.0-2813.0) m. the reservoir (mi4) was composed of limestone mainly divided into two sections with a porosity of 0.17-0.19, a pore fluid viscosity of 1.5-1.7 cp, a pore pressure gradient of 0.51 psi/ft, and a fracture pressure gradient of 0.751-0.76 psi/ft respectively. there was a preflush of 2 percent potassium chloride brine, followed by the pumping of 20 percent hydrochloric acid. before shutting down, the same brine injected to perform an overflush. the total amount of acid used in the job was 34.5 m3. surface pressure and pumping rate were recorded during the job. all the entered data is shown in considerable detail in table 1 to table 10. table 1. acidizing summary reservoir temperature (°f) 200 average reservoir pressure (psi) 4,694 pore fluid permeability (md) 15-60 porosity 0.190 reservoir viscosity (cp) 1.637 frac pressure (psi) 6,995 tvd to top of open section (m) 2,798 tvd to bott. of open section (m) 2,813 acidizing type carbonate acid volume (bbls) 103.9 avg. surface pressure (psi) 2,534 max. surface pressure (psi) 2,627 initial skin 0 final skin -3.97 u. alameedy et al. / iraqi journal of chemical and petroleum engineering 23,4 (2022) 7 16 11 fig. 4. daily acidizing report for well ad-12 table 2. fluid parameters fluid name 2% kcl brine fresh water 15% hcl gelled acid description preflush/overflush fluid fresh water gelled acid hcl conc. (% mass) 0.0 0.0 20.0 fluid density 1.000 1.000 1.080 diffusivity (ft²/min) 4.30e-06 4.30e-06 4.30e-06 retardation factor 1.00 1.00 1.00 filtercake porosity 0.01 0.01 0.01 filtercake permeability (md) 1.00e-04 1.00e-04 1.00e-04 initial viscosity (cp) 1.00 1.00 initial n' 1.000 initial k' (lbf·s^n/ft²) 2.10e-05 wellbore friction multiplier 1.00 1.00 1.00 table 3. formation layer parameters layer # top of zone md (m) lithology pore fluid permeability (md) reservoir viscosity (cp) compressibility (1/psi) porosity pore pressure (psi) frac pressure (psi) 1 0.0 shale 0.00e+00 2.000 5.00e-06 0.000 3,045 5,000 2 2,798.0 limestone 15 1.500 5.00e-06 0.170 4,686 6,900 3 2,802.7 limestone 60 1.700 5.00e-06 0.190 4,698 7,001 4 2,813.0 shale 0.00e+00 0.030 2.49e-04 0.000 4,015 7,383 u. alameedy et al. / iraqi journal of chemical and petroleum engineering 23,4 (2022) 7 16 12 table 4. damage profile int md (m) damage severity original skin damage penetration damage depth(ft) damage composition 1 0 light 0.0 shallow 0.00 shale 2 2,800 light 3.0 shallow 0.20 limestone 3 2,807 light 3.0 medium 0.30 limestone 4 2,813 light 0.0 shallow 0.00 shale table 5. drilled hole configuration length (m) segment type eff diam (in) bit diam (in) 2,814 open hole 8.500 8.500 table 6. casing configuration length (m) segment type casing id (in) casing od (in) weight (lb/ft) grade 2,814 cemented casing 6.520 7.000 17.000 n-80 table 7. surface line and tubing configuration length (m) segment type tubing id (in) tubing od (in) weight (lb/ft) grade 2,700 tubing 2.362 2.875 4.600 n-80 2 packer 2.370 6.500 0.000 table 8. path summary segment type length (m) md (m) tvd (m) dev (deg) pipe id (in) tubing 2,700 2,700 2,700 0.0 2.362 casing 113 2,813 2,813 0.0 6.520 table 9: rock thermal properties rock type sandstone limestone shale specific gravity (sg) 2.71 2.72 2.71 specific heat* 0.260 0.210 0.200 thermal conductivity** 2.57 0.910 1.01 table 10. fluid thermal properties fluid name 2% kcl brine fresh water 15% hcl gelled acid specific gravity (sg) 1.000 1.000 1.08 parameters for heat transfer model surface fluid temperature 70.00 (°f) surface rock temperature 70.00 (°f) reservoir temperature 200 (°f) wellbore heat transfer multiplier 1.00 the stimpro acidizing model considers the intrinsic variances in matrix acid for carbonates and sandstones. as wormholes grow in carbonates, matrix stimulation is more effective because it allows the formation to be penetrating farther than the damaged near-wellbore area allows. wormhole development in carbonate acidizing may be calculated using two different models in this new edition of stimpro: a semi-empirical method by [16] is used as the default model, whereas péclet number theory is used for the alternate model [17]. carbonate matrix acidizing treatment is optimized by considering both the wormhole skin and the transient radial flow pressure.  pressure matching once all the necessary data and parameters have been input, we begin the simulation using the semi-empirical model with 𝑃𝑉bt−opt= 0.55 and 𝑉𝑖−opt=0.0322 ft/min stored in the software database [16]. afterward, a comparison of the pressure match plot between calculated and measured wellhead pressure is performed and a comparison between calculated and measured bottomhole pressure. treatment data with bottom hole and fracture pressures may be shown in fig. 5, which displays the results of our studies; fluctuating fluid diverting effects cause bottomhole pressure to vary. for matrix acid treatments, jobs were typically pumping below the hydraulic fracture pressure of the formation pressure. the model's reaction to its experimental work data built-in software is overstated since the modeled pressure values are substantially lower than the actual data. therefore, the simulated pressure data does not very well match the observed pressure data. utilizing our experimental [9] data 𝑃𝑉bt−opt=2.5 and 𝑉𝑖−opt=0.0206 ft/min as input data to enhance the pressure match. thus, a more accurate match between estimated and observed surface pressures is achieved (fig. 6). once sufficient pressure data has been obtained, the changing skin may be anticipated. figure 5.33 demonstrates that the treatment reduced the wellbore skin from around 3 at the start of the operation to approximately -3.6 at the end of job. most likely, deeppenetrated wormholes were generated in the carbonate formation, ensuring the effectiveness of this acid treatment. the fig. 7 illustrates the estimated skin, injection rate, and acid concentration of fluid for three phases of treatment, all of which are proportional to the time spent acidifying the matrix. referring to the buildup analysis for ad-12 [9], the skin value of -3.97 is approximately identical to or slightly larger than the skin value estimated by the acid treatment simulation using stimpro software. the depth profile is shown in fig. 8 summarizes the reservoir parameters, formation damage, and the model computation of fluid invasion via the flushed formation in three phases. as can be discriminated, the treated zones are divided into two layers based on the formation layer parameters (table 5 to table 9); the first layer is 4.7 m thick with a permeability of 15 md and a porosity of 0.17; the second layer is 10.3 m thickness with a permeability of 65 md and a porosity of 0.19. when the simulator was performed, the invading fluid revealed two distinct depths of investigation inside the treated zone. the fluid invasion in the bottom area has remained steady at a distance of 95 inches (7.91 ft) despite the top layer wormhole penetrating to a depth of 32 inches (2.67 ft). the effective permeability of two layers is 15-60 md; accordingly, utilizing eq. (5) to compute wellhead or bottom hole injection pressure for various skin factor (s) values since assuming acid injection rates. as a result, the computation is shown in the fig. 9, which plots many curves of injection rate vs. wellhead pressure, one for each skin component (s). it is found that most predicted wellhead pressures are less than the fracture pressure, indicating that the acid job treatment may be conducted u. alameedy et al. / iraqi journal of chemical and petroleum engineering 23,4 (2022) 7 16 13 safely without breaking the formation. the only problem is that if there is formation damage to the skin of 5, and the injection rate exceeds 5 bpm, the bed will frack, indicating that the treatment job will fail. fig. 5. the pressure match between actual and calculated for surface and bottom hole of stimulated well ad-12 fig. 6. the pressure match between actual and calculated for surface and bottom hole of stimulated well ad-12, using our data set u. alameedy et al. / iraqi journal of chemical and petroleum engineering 23,4 (2022) 7 16 14 fig. 7. skin factor computation for well ad-12 fig. 8. invasion profile, layer properties and model treatments schedule for well ad-12 fig. 9. treatment of the matrix stimulation design chart for well ad-12 u. alameedy et al. / iraqi journal of chemical and petroleum engineering 23,4 (2022) 7 16 15 7conclusions in stimpro software, the model's response to its experimental work data has been overestimated since the predicted pressure levels are far lower than the real data. as a result, the simulated data on pressure does not match the actual data on pressure very well. experiment with a pressure match of pvbt =2.5 and vi= 0.206 ft/min, using our experimental data as input data. as a result, the predicted and measured surface pressures are more closely matched. the changing skin may be predicted if enough pressure data is collected. wellbore skin was decreased from around 3 at the commencement of the operation down to about -3.6 at the completion of the project. the acid treatment's success was presumably ensured by creating deep-penetration wormholes in the carbonate deposit. stimpro's acid treatment simulation predicted a skin value of -3.97 for ad-12, which is close to or slightly bigger than the skin value predicted by the buildup analysis. references [1] m. j. economides, a. d. hill, c. ehlig-and economides, and d. zhu, petroleum production systems, secodn edi. pentice hall, 2013. [2] m. j. economides and k. g. nolte, rerservoir stimulation, 3rd ed. wiley, 2000. [3] m. j. economides, a. d. hill, and c. ehlig-and economides, petroleum production systems. 1994. [4] u. s. alameedy, “evaluation of hydrocarbon saturation using carbon oxygen (co) ratio and sigma tool,” iraqi j. chem. pet. eng., vol. 15, no. 3 se-articles, pp. 61–69, sep. 2014. [5] j. a. al-sudani and k. m. husain, “evaluation of acid and hydraulic fracturing treatment in halfaya oil field-sadi formation,” iraqi j. chem. pet. eng., vol. 18, no. 4 se-articles, pp. 25–33, dec. 2017. [6] m. najeeb, f. s. kadhim, and g. n. saed, “using different methods to predict oil in place in mishrif formation / amara oil field,” iraqi j. chem. pet. eng., vol. 21, no. 1 se-articles, pp. 33–38, mar. 2020, doi: 10.31699/ijcpe.2020.1.5. [7] u. alameedy, “experimental study and analysis of matrix acidizing for mishrif formation-ahdeb oil field,” phd, dissertation, university of baghdad, 2022, doi:10.13140/rg.2.2.25412.91525. [8] t. o. allen and a. p. roberts, production operations, 3rd printi. tulsa, oklahoma: vol.2., 1978. [9] u. alameedy and a. al-haleem, “the impact of matrix acidizing on the petrophysical properties of the mishrif formation: experimental investigation,” iraqi geol. j., vol. 55, no. 1e, pp. 41–53, may 2022, doi: 10.46717/igj.55.1e.4ms-2022-05-20. [10] u. alameedy, a. a. alhaleem, a. isah, a. al-yaseri, m. mahmoud, and i. s. salih, “effect of acid treatment on the geomechanical properties of rocks: an experimental investigation in ahdeb oil field,” j. pet. explor. prod. technol., jul. 2022, doi: 10.1007/s13202-022-01533-x. [11] g. paccaloni, m. tambini, and m. galoppini, “key factors for enhanced results of matrix stimulation treatments,” feb. 1988, doi: 10.2118/17154-ms. [12] y. wang, a. d. hill, and r. s. schechter, “the optimum injection rate for matrix acidizing of carbonate formations,” spe annual technical conference and exhibition. p. spe-26578-ms, oct. 03, 1993, doi: 10.2118/26578-ms. [13] g. paccaloni and m. tambini, “advances in matrix stimulation technology,” j. pet. technol., vol. 45, no. 03, pp. 256–263, mar. 1993, doi: 10.2118/20623pa. [14] l. p. prouvost and m. j. economides, “applications of real-time matrix-acidizing evaluation method,” spe prod. eng., vol. 4, no. 04, pp. 401–407, nov. 1989, doi: 10.2118/17156-pa. [15] carbo, “tutorial manual.” 2021. [16] m. buijse and g. glasbergen, “a semi-empirical model to calculate wormhole growth in carbonate acidizing,” oct. 2005, doi: 10.2118/96892-ms. [17] g. daccord, e. touboul, and r. lenormand, “carbonate acidizing: toward a quantitative model of the wormholing phenomenon,” spe prod. eng., vol. 4, no. 01, pp. 63–68, feb. 1989, doi: 10.2118/16887-pa. https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/289 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/289 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/289 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/289 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/69 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/69 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/69 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/69 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/541 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/541 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/541 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/541 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/541 http://dx.doi.org/10.13140/rg.2.2.25412.91525 https://igj-iraq.org/igj/index.php/igj/article/view/942 https://igj-iraq.org/igj/index.php/igj/article/view/942 https://igj-iraq.org/igj/index.php/igj/article/view/942 https://igj-iraq.org/igj/index.php/igj/article/view/942 https://igj-iraq.org/igj/index.php/igj/article/view/942 https://link.springer.com/article/10.1007/s13202-022-01533-x https://link.springer.com/article/10.1007/s13202-022-01533-x https://link.springer.com/article/10.1007/s13202-022-01533-x https://link.springer.com/article/10.1007/s13202-022-01533-x https://link.springer.com/article/10.1007/s13202-022-01533-x https://link.springer.com/article/10.1007/s13202-022-01533-x https://onepetro.org/spefd/proceedings-abstract/88fd/all-88fd/spe-17154-ms/67691 https://onepetro.org/spefd/proceedings-abstract/88fd/all-88fd/spe-17154-ms/67691 https://onepetro.org/spefd/proceedings-abstract/88fd/all-88fd/spe-17154-ms/67691 https://onepetro.org/speatce/proceedings-abstract/93spe/all-93spe/spe-26578-ms/55234 https://onepetro.org/speatce/proceedings-abstract/93spe/all-93spe/spe-26578-ms/55234 https://onepetro.org/speatce/proceedings-abstract/93spe/all-93spe/spe-26578-ms/55234 https://onepetro.org/speatce/proceedings-abstract/93spe/all-93spe/spe-26578-ms/55234 https://onepetro.org/speatce/proceedings-abstract/93spe/all-93spe/spe-26578-ms/55234 https://onepetro.org/jpt/article-abstract/45/03/256/70458/advances-in-matrix-stimulation-technology https://onepetro.org/jpt/article-abstract/45/03/256/70458/advances-in-matrix-stimulation-technology https://onepetro.org/jpt/article-abstract/45/03/256/70458/advances-in-matrix-stimulation-technology https://onepetro.org/jpt/article-abstract/45/03/256/70458/advances-in-matrix-stimulation-technology https://onepetro.org/po/article-abstract/4/04/401/76597/applications-of-real-time-matrix-acidizing?redirectedfrom=fulltext https://onepetro.org/po/article-abstract/4/04/401/76597/applications-of-real-time-matrix-acidizing?redirectedfrom=fulltext https://onepetro.org/po/article-abstract/4/04/401/76597/applications-of-real-time-matrix-acidizing?redirectedfrom=fulltext https://onepetro.org/po/article-abstract/4/04/401/76597/applications-of-real-time-matrix-acidizing?redirectedfrom=fulltext https://onepetro.org/speatce/proceedings-abstract/05atce/all-05atce/spe-96892-ms/89467 https://onepetro.org/speatce/proceedings-abstract/05atce/all-05atce/spe-96892-ms/89467 https://onepetro.org/speatce/proceedings-abstract/05atce/all-05atce/spe-96892-ms/89467 https://onepetro.org/po/article-abstract/4/01/63/76503/carbonate-acidizing-toward-a-quantitative-model-of?redirectedfrom=fulltext https://onepetro.org/po/article-abstract/4/01/63/76503/carbonate-acidizing-toward-a-quantitative-model-of?redirectedfrom=fulltext https://onepetro.org/po/article-abstract/4/01/63/76503/carbonate-acidizing-toward-a-quantitative-model-of?redirectedfrom=fulltext https://onepetro.org/po/article-abstract/4/01/63/76503/carbonate-acidizing-toward-a-quantitative-model-of?redirectedfrom=fulltext https://onepetro.org/po/article-abstract/4/01/63/76503/carbonate-acidizing-toward-a-quantitative-model-of?redirectedfrom=fulltext u. alameedy et al. / iraqi journal of chemical and petroleum engineering 23,4 (2022) 7 16 16 في حقل نفط mi4 : دراسة حالة لوحدةحشو الصخري ض التحميأداء البئر بعد معالجة األحدب 2عبد االمير المالكي و 1, اياد عبد الحليم1أسامة العميدي جامعة بغداد –كلية الهندسة -قسم هندسة النفط 1 جامعة ميسكولك –كلية علوم وهندسة االرض –قسم هندسة النفط 2 الخالصة صادر ميمكن تحسين إنتاجية آبار النفط من خالل تحديد قيمة تحسين إنتاجية البئر واألسباب المحتملة أو الضرر الناتج عن التكوين بعد التعرف على أن أداء البئر ضعيف. قد تتحسن إنتاجية آبار النفط، لكن صادي على الحد االقت skinللخطر. من المهم تحليل تأثير تأثير اقتصاديات هذا التحسن التدريجي قد تتعرض .للخطر skinواستعادة االحتياطي. قد تتعرض اقتصاديات التحسن التدريجي لتأثير التي ر، متجاوزة األضرايةالكربونالصخور ، تتشكل قنوات جديدة )ثقوب دودية( في معالجة بالحامضلانتيجة بعدزمنيا ضخ ال يتم جدولة stimpro باستخدام برنامج. ربتدفق المياه إلى البئبئر وتسمح لحقت بجوف ال 2011ديسمبر 2. تقرر القيام بمهمة التحميض في الطبقي التضرراختيار السوائل واألحماض المناسبة لنوع من النتهاء ، إلزالة أضرار طين الحفر وا mi4مشرف، وال سيما وحدة مكمنالذي يستهدف ad-12 للبئر stimpro يستخدم .منطقة الدفع وتحسين أداء التكوين من خالل تعزيز النفاذية، وبالتالي زيادة إنتاج النفط محمضة وإظهار كيف تتوافق بيانات الضغط المقاسة والمحاكاة. للبدء، الصخور الكربونيةلتحليل معالجة .ستحتاج إلى جمع بيانات عن حالة البئر ونوع السوائل وخطة العالج .المعالجة بالحامضمشرف, مكمن الكلمات الدالة: iraqi journal of chemical and petroleum engineering vol.17 no.2 (june 2016) 69-77 issn: 1997-4884 cfd simulation of air flow patterns in a spray dryer fitted with a rotary disk saad nahi saleh and laith amjad hameed tikrit university, college of engineering, chemical engineering department tikrit, salah el-din, iraq abstract the air flow pattern in a co-current pilot plant spray dryer fitted with a rotary disk atomizer was determined experimentally and modelled numerically using computational fluid dynamics (cfd) (ansys fluent ) software. the cfd simulation used a three dimensions system, reynolds-average navier-stokes equations (rans), closed via the rng k −ε turbulence model. measurements were carried out at a rotation of the atomizer (3000 rpm) and when there is no rotation using a drying air at 25 o c and air velocity at the inlet of 5 m/s without swirl. the air flow pattern was predicted experimentally using cotton tufts and digital anemometer. the cfd simulation predicted a downward central flowing air core surrounded by a slow recirculation zones near the walls for both conditions. analysis of cfd simulation revealed that rotation of atomizer resulted in a swirling motion of the central air core. simulations results were in good agreement with experimental data. key words: cfd, spray, rotary, dryer, simulation. introduction spray drying is a transformation process of a solution into a dried form by spraying it into a hot drying medium. this drying technique is common to many industries for the production of chemical, foodstuffs, detergents, pharmaceuticals and cosmetics [1]. the dried product can be in the form of powders, granules or agglomerates depending upon the chemical and physical properties of the feed, design of the dryer and final desired properties for product [2]. one of the most important phenomena which influences on the operation of the spray dryer is air flow pattern within the dryer. air flow has effects on droplets trajectories, residence time distribution of droplets and deposition of the droplets on the wall [3, 4]. therefore an accurate knowledge of the air flow pattern inside the spray dryer will help to operate the dryer at conditions that produce powders with desired equality. numerous numerical studies have been published for analysis of the air flow pattern in the spray dryer[5-7]. the computational fluid dynamics (cfd) simulation has proven to be a valuable tool in understanding and analyzing of the air flow patterns within spray dryers [8]. iraqi journal of chemical and petroleum engineering university of baghdad college of engineering cfd simulation of air flow patterns in a spray dryer fitted with a rotary disk 70 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net the steady state air flow pattern was investigated numerically by solving navier-stockes equations to predict the motion of air in a spray dryer [9, 10] a central flowing jet with a recirculation zone near the wall have been captured in a co-current spray dryer using cfd simulations [11, 12]. it was found that the simulation of the spray dryer fitted with a rotating atomizer yielded a relatively symmetrical air flow pattern [13]. the aim of this work is to predict air flow pattern experimentally and investigate numerically the behavior of air flow inside the spray dryer fitted with a rotary atomizer at a case of no solution was sprayed. experimental work the tests were conducted in a pilot plant spray dryer with total product discharge which is shown in fig. (1). it is a co-current dryer with an internal diameter of 0.80 m, a cylindrical fig. 1, pilot plant spray dryer. section height of 1.0 m and a conical section height of 0.69m [14]. at the top of the dryer, a rotary disk atomizer of 6 cm diameter is fitted and air enters the dryer via an annulus inlet opening (fig. 2). the dryer main air inlet has a zero swirl condition with the flow direction normal to the inlet. a schematic diagram of the spray dryer chamber is shown in fig. (3). visualization of the air flow field in the dryer was performed experimentally by two methods: 1quantitative flow prediction digital anemometer (0-10 m/s measuring range, 0.1 m/s accuracy, 0.01 m/s resolution) was utilized at various height and radial to give an indication of the air flow inside the dryer. 2qualitative flow prediction grid of cotton tufts was utilized to assess the flow characteristics inside the spray dryer at conditions that are with and without rotation of the disc atomizer. the cotton tufts were suspended in circles (r1, r2 and r3) locating about the axis and along three levels of lengths (c1, c2 and c3) within the dryer chamber as shown in fig. (4). fig.2, rotary disk saad nahi saleh and laith amjad hameed -available online at: www.iasj.net ijcpe vol.17 no.2 (june 2016) 71 fig. 3, schematic diagram of dryer chamber (the dimensions in cm) fig. 4, the grid of cotton tufts used in the dryer chamber. the computational model in order to determine accurately the air flow features inside the spray dryer, cfd simulation was used with the software ansys fluent version 15 [15] in which a three dimensional model was adapted for air flow modeling. for modeling the air flow, the equations of continuity, momentum, turbulent kinetic energy, and dissipation rate of turbulent kinetic energy are applied. following are the reynolds averaged navier-stokes equations (rans) and the rng k-ɛ model as a turbulence model:   0u t     … (1)     uu t u      t eff uup    … (2)         keffk gkuk t k  ... (3)     u t    k cg k c 2 2k1eff      ... (4) where    2 tteff k c and the rng k-ɛ model’s constants c1, c2, cμ are 1.42, 1.68 and 0.0845 respectively [15]. mesh generation geometry of the dryer chamber was created using the software gambit where a three-dimensional unstructured mesh was constructed using 78216 hexahedral cells. the surface mesh of the spray dryer chamber is shown in fig. (5). cfd simulation of air flow patterns in a spray dryer fitted with a rotary disk 72 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net fig. 5, surface mesh for the dryer chamber boundary conditions the simulation was isothermal, using a drying air at 25 o c with the flow direction normal to the inlet, and no droplets were injected. the air velocity at the inlet was set to 5 m/s without swirl and the average static pressure set to zero at the outlet. the turbulent kinetic energy (k) = 0.027 m 2 /s 2 , rate of dissipation (ε) = 0.37 m 2 /s 3 . the no slip boundary condition with standard log-law wall functions were used to solve the turbulence and air velocity near the walls. numerical solution the simulations were performed for steady state operation using ansys fluent software, which uses a finite volume discretization method to solve the fluid flow equations in the computational domain. for the convective terms, the secondorder upwind discretization scheme was used and for the pressure-velocity coupling the simple scheme was used. the convergence criteria for the continuity, momentum, turbulent kinetic energy and rate of dissipation were specified as 1× 10 -5 . results and discussion 1experimental results by observing the motion of the cotton tufts (through the sight glass mounted on the dryer chamber) at a case of atomizer stopped, it was possible to distinguish a zone of a recirculation movement of the tufts at the (r3, c2) region and an upwards motion at the tufts at the (r3, c3) region. the velocities magnitude measured using the digital anemometer are illustrated in fig. (6) at different vertical distance from the ceiling of the dryer. it is shown that the velocity decrease with increasing of radial distance from the center to the wall for all vertical levels and the velocity is decreased as the air goes into the dryer further due to expanding area. the measurements reveal that the velocity profiles near the center of the dryer are quite different at the vertical levels where a low velocity region at 10 cm level (just under the atomizer on the ceiling) is occurred because the ceiling plate blocks air flow. by these predictions, it is clear that air flow consists of a central air core with radius about 10 cm and a slow recirculation zones around that core. saad nahi saleh and laith amjad hameed -available online at: www.iasj.net ijcpe vol.17 no.2 (june 2016) 73 fig. 6, radial distribution of measured air velocity for no rotational case at different vertical levels for atomizer running case (3000 rpm), observation of the cotton tufts revealed a downward movement of air flow near the central region towards the exit in a strong clockwise swirling motion, due to the atomizer rotating in that direction. the cotton tufts at the region (c3, r3) were moved to upward and this indicates presenting an upward recirculation zone at this region. this motion continued to the region (c2, r3) at which a recirculation zone around the central air core was appeared. fig (7) shows the air velocity magnitude measured using the digital anemometer at 3000 rpm rotation of atomizer. by comparing it with measured velocity of no rotation of atomizer (fig. (6)), the main features of air flow pattern for two cases (no rotation and 3000 rpm rotation of atomizer) are almost similar where the air core of about 10 cm radius surrounding by a low velocity region is a distinct behavior in both cases. fig. 7, radial distribution of measured air velocity magnitude for rotational case at different vertical levels 2simulations results in this section, the analysis of air flow pattern simulated in the pilot plant spray dryer was presented. as shown in fig. (8) for the no rotation atomizer case, the air flow pattern inside the dryer chamber consists of the air core and low velocity zones around that core. fig. 8, predicted air velocity magnitude (m/s) contour at without rotation of atomizer. -1 0 1 2 3 4 5 6 0 10 20 30 40 v e lo ci ty m a g n it u d e m /s radial distance cm at 10 cm at 30 cm at 60 cm -1 0 1 2 3 4 5 0 10 20 30 40 v e lo ci ty m a g n it u d e m /s radial distance cm at 10 cm at 30 cm at 60 cm cfd simulation of air flow patterns in a spray dryer fitted with a rotary disk 74 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net fig.(9) shows the air velocity magnitude at different vertical levels where the air core broadens as it moves further downstream into the chamber. fig. 9, predicted air velocity magnitude (m/s) contours for no rotation case at different vertical levels. the simulation results revealed that an air recirculation region was predicted at the cylindrical-conical interface of the dryer chamber as shown in fig (10). fig. 10, predicted air velocity magnitude (m/s) contour at conical part of dryer chamber for no rotational case figure (11) shows the air velocity magnitude profiles with radial distance from the center at different vertical levels (10, 30 and 60 cm from the ceiling). there is a good agreement with the experimental results with a deviation of about (8%) from experimental data. (fig. (6)). it is noted that the predicted air core radius was about 10 cm and this is very close to that estimated from experiments. fig. 11, radial distribution of predicted air velocity magnitude for no rotation case at different vertical levels simulation results for rotational case show a swirling motion of air core where this motion continues til the conical part of the chamber as shown in fig. (12). thus the tangential component of velocity governs the main flow whereas the radial and axial velocities are almost negligible. due to the swirling motion of the air core, it is noted that the center had a lower velocities than that were at near the center of the core as shown clearly in fig. (13) and especially at 10 cm vertical level. in comparison with no rotation atomizer, the air core have a higher velocities as it moves downward ,although the air flow structure for both cases is the same saad nahi saleh and laith amjad hameed -available online at: www.iasj.net ijcpe vol.17 no.2 (june 2016) 75 fig. 12, predicted air velocity magnitude (m/s) contour for rotational case fig. 13, radial distribution of predicted air velocity profile for rotational case at different vertical levels another comparison of predicted tangential velocities for the two cases is shown in fig. (14) in which air flow structure is asymmetrical for no rotation case (a) whereas for rotation case, the central air core is surrounded by an alternative regions of clockwise and anticlockwise flow motion and this is an acceptable agreement to what observed qualitatively by the experimental tests. therefore, the air flow pattern for rotational case can be described as a structure of symmetrical nature which was also captured by another model [12]. the predicted axial velocity for rotational case is shown in fig. (15). it is seen that there is a slightly reverse flow at 10 cm level because of the rotating atomizer which pulls the air flow below the atomizer upwards. this phenomenon was called as air pumping and predicted numerically [16]. near the wall, a revers flow is also shown and this is belonging to appearance of the air recirculation zones. fig. 14, comparison of predicted tangential air velocity (m/s) contours for no rotation (a) and rotation (b) cases at different vertical levels. cfd simulation of air flow patterns in a spray dryer fitted with a rotary disk 76 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net fig. 15, radial distribution of predicted axial velocity profile for rotation case at different vertical levels conclusions the cfd simulation captured the main features of air flow structure for no rotation and rotation of atomizers cases. the air flow in both cases consists of a central air core surrounded by a low recirculation zones. in the rotation case, the rotation of atomizer resulted in a swirling motion of the central core moving downward to the chamber outlet. this rotation created an anticlockwise motion surrounding the central core. generally the rotation of the atomizer increased the central air core velocity and caused an occurrence of the air pumping below the atomizer. the agreement between experimental observations and simulations revealed a deviation of about (8%) from experimental data. nomenclature c1, c2, cμ constants c1, c2, c3 axial position (cm) gk generation of turbulent kinetic energy, kg/m.s 3 k turbulent kinetic energy,m 2 /s 2 p air pressure, pa r1, r2, r3 radial position (cm) u air velocity, m/s t time, s greek symbols ɛ turbulent kinetic energy dissipation rate, m 2 /s 3 μ viscosity, pa.s μeff effective viscosity, pa.s μt turbulent viscosity, pa.s ρ density, kg/m 3 αk,αɛ turbulent prandtl numbers references 1masters, k., (1991), “spray drying handbook”, longman scientific and technical: harlow, uk. 2michael, j.k., (1993), “spray drying and spray congealing of pharmaceuticals”. in: encyclopedia of pharmaceutical technology, marcel dekker inc, ny, vol. 14, pp. 207. 3kota, k.; langrish, t., (2007) “prediction of deposition patterns in a pilot scale spray dryer using computational fluid dynamics (cfd) simmulations”, chemical product and process modeling, no.3, vol. 2, article 26. 4sadripour, m.; rahimi, a.; hatamipour, m.s., (2012), “ experimental study and cfd modeling of wall deposition in a spray dryer “, drying technology, no.6, vol.30, pp.574. 5roustapour, o.r. ; hosseinalipour, m.h. ; ghobadian, b.; mohaghegh, f. ; neda, n.m., (2009), “a proposed numerical–experimental method for drying kinetics in a spray dryer”, journal of food engineering, vol. 90, pp. 20. saad nahi saleh and laith amjad hameed -available online at: www.iasj.net ijcpe vol.17 no.2 (june 2016) 77 6southwell, d.b.; langrish, t.a.g, (2000), “observations of flow patterns in a spray dryer”, drying technology, vol. 18,pp. 661. 7fletcher, d.f.; langrish,t.a.g., (2009), “scale-adaptive simulation (sas) modelling of a pilot-scale spray dryer, chemical engineering research and design, vol.87, pp.1371. 8oakley, d.e., (1994), “scale-up of spray dryers with the aid of computational fluid dynamics”, drying technology, vol.12, no. 1, pp.217. 9kieviet, f.g, (1997), “modelling quality in spray drying”, ph.d. thesis, t.u. eindhoven, the netherlands. 10huang, l.x.; kumar, k.; mujumdar, a.s., (2003), “a parametric study of the gas flow patterns and drying performance of co-current spray dryer: results of a computational fluid dynamics study”, drying technolgy, no. 6, vol. 21, pp. 975. 11saleh, s.n., “prediction of air flow, temperature and humidity patterns in a pilot plant spray dryer”, (2010), nahrain university, college of engineering journal (nucej), no.1, vol. 13, pp.55. 12woo, m.w.;che , l.m.; daud , w.r.w.; mujumdar , a.s. ; chen, x.d., (2012), “highly swirling transient flows in spray dryers and consequent effect on modeling of particle deposition”, chemical engineering research and design, vol. 90, pp. 336. 13ullum, t.,”simulation of a spray dryer with rotary atomizer: the appearance of vortex breakdown”, (2006), proceedings of the 15 th international drying symposium, pp.251. 14laith amjad hameed, (2014), “simulation and experimental work of air flow pattern in a spray dryer by using cfd”, m.sc. thesis, tikrit university, iraq. 15ansys fluent 15 , (2014), theory guide, ansys inc. 16haung, l.x.; kumar, k.; mujumdar, a.s., (2006), “ a comparative study of a spray dryer with rotary disc atomizer and pressure nozzle using computational fluid dynamics simulations”, chemical engineering and processing, vol. 45, pp.461. iraqi journal of chemical and petroleum engineering vol.14 no.3 (september 2013) 1121 issn: 1997-4884 effect of additives on the properties of different types of greases muhannad a.r. mohammed chemical engineering department, college of engineering, al-nahrain university abstract the aim of this research is to study the influence of additives on the properties of soap greases, such as lithium, calcium, sodium, lithium-calcium grease, by adding varies additives, such as graphite, molybdenum disulfide, carbon black, corrosion inhibitor, and extreme pressure. these additives have been added to grease to obtain the best percentages that improve the properties of grease such as load carrying, wear resistance, corrosion resistance, drop point, and penetration. the results showed the best weight percentages to all types of grease which give good properties are 1.5% extreme pressure additive, 3% graphite, 1% molybdenum disulfide, 2.5% carbon black. the other hand, the best weight percentage for corrosion inhibitor is 1% to lithiumcalcium grease, 2% to lithium grease, and 3% to sodium grease. it was concluded that there is no need to add corrosion inhibitor to calcium grease. key words: greases, lubrication, lubricating oil introduction grease is a complex multi-phase material whose way of functioning needs to be clarified because of its growing use in modern machines [1]. true grease consists of oil and or other fluid lubricant that is mixed with another thickener substance such as a soap to form a solid. greases generally cannot satisfy the requirements of high performance lubricants without using the benefits of modern additive technology. additives are natural or synthetic chemical substances that can improve lots of different parameters of lubricants [2]. anti-wear and extreme pressure (ep) additives improve, in general the load carrying ability in most rolling contact bearings and greases. fillers are sometimes used as fine solids in grease formulations to improve grease performance. typical fillers are graphite, molybdenum disulfide, carbon black and others [3]. the important properties which affect the characteristics of grease are amount and type of thickener, oil viscosity, additives and low or high temperature performance. additives enhance performance and protect the grease [4]. the grease is a mixture of a fluid lubricant, a thickener, and additives. common thickeners are the fatty acid soaps of lithium, calcium, sodium, aluminum, and barium or in organic non soap thickeners [5]. lederer in 1933 introduced first greases which are aluminum soap – iraqi journal of chemical and petroleum engineering university of baghdad college of engineering effect of additives on the properties of different types of greases 12 ijcpe vol.14 no.3 (september 2013) -available online at: www.iasj.net based, used the aluminum soap represented by aluminum stearate [20]. calhoun in 1962, reported that the tendency of molybdenum disulfide to decrease the wear of grease. however, the extreme pressure properties of greases were increased by the addition of this agent [21]. tarunendr singh in 2000, showed that the blends of bis (1,5-diaryl-2,4dithiomalonamido) dioxomolybdenum complexes in lithium base grease are evaluated for their extreme pressure activity. the greases fortified with additives, prevent rusting and corrosion of bearings, and also have better oxidation protection as compared to the grease have no additive [22]. edward in 2003 showed that greases composed of mineral oil blended with a soap thickener, additives enhance performance and protect the grease and lubricant surfaces [4]. theo et.al in 2007 stated that the greases cannot satisfy the requirements of high performance lubricants without using the benefit of modern additive, such as corrosion inhibitor, antiwear, and extreme pressure additives [2]. the aim of this work is to study the influence of some additives on properties of (lithium, calcium, sodium, and lithium – calcium) soap greases by adding; additives which include graphite, molybdenum disulfide, carbon black, corrosion inhibitor, and extreme pressure additives additives can play several roles in lubricating grease. these primarily include enhancing the existing desirable properties, suppressing the existing undesirable properties, and imparting new properties [8]. the most common additives are oxidation inhibitors, corrosion inhibitors, extreme pressure, antiwear, viscosity index improver and friction modifiers such molybdenum disulfide or graphite. 1. antioxidants greases are apparently oxidized in different ways statically as in storing and dynamically as in service because of the different temperature involved [6]. oxidation inhibitor is natural antioxidants among the most important additives used in greases. the steps involving in the oxidation are initiation, propagation and termination. oxidation inhibitors function by preferentially combining with peroxides or radical species, there by terminating the free radical chain reaction. chemical compounds typically used to inhibit oxidation include hindered phenols, aromatic amines, heterocyclic nitrogen compounds, and zinc di-alkyl dithiophosphate and di-thiocarbonates [7]. 2. corrosion and rust inhibitor corrosion and rust inhibitor completely coat the metal, in order to protect these surfaces from rusting, since rusting is an electrochemical process and proceeds in the presence of air-providing oxygen and water. two types of corrosion inhibitors are used commercially: oil soluble material, such as lead soaps, molybdenum disulfide, and water soluble compounds protect by strong adsorption on the metal. sodium nitrite is corporate as dispersion of very small crystals to avoid roughness in bearing [8]. 3. extreme pressure (anti wear agents) the addition of this additive to lubricate grease increases mechanical efficiency and diminishes wear and destructive heating reducing friction muhannad a.r. mohammed -available online at: www.iasj.net ijcpe vol.14 no.3 (september 2013) 13 and avoiding surface damage of sliding surfaces whilst increasing the load carrying capacity [9]. molybdenum disulfide has the advantage of durability under severe operating conditions such as temperature up to 400 °c [10]. 4. viscosity modifiers viscosity modifiers are generally oil soluble organic polymers. many types of viscosity modifiers are available, such as polyisobutylene, volatilized paraffin wax, unsaturated polymerized esters of fatty acids and monohydric alcohols, and condensation products of olefin and diolefin hydrocarbons [11]. these modifiers consist of aliphatic carbon to carbon backbones. the major structural differences are in the side groups, which differ chemically and in size. these variations in chemical structure are responsible for various properties of viscosity modifiers such as, oil-thickening ability, viscosity temperature dependency, and oxidation stability [8]. types of greases 1. calcium soap grease it is one of the earliest known greases and is water resistant and mechanically stable. calcium soap grease usually has a low dropping point; typically 95 °c. high temperatures cause a loss of water and a consequent weaking of soap structure, and therefore the use of this grease is limited to a maximum temperature of about 60 °c [12]. 2. sodium soap grease it is fibrous in structure and is resistant to moderately high temperature but not to water. sodium soap grease has a high dropping point (175 °c) than calcium grease [12]. 3. aluminum soap grease it is smooth, transparent grease with poor shear stability but excellent oxidation and water resistance, but tends to have poor mechanical stability and so is not suitable for rolling bearings [12]. 4. lithium soap grease it is normally smooth in appearance but may exhibit a grain structure. lithium soap grease offers both the water resistance of calcium soap grease and high-temperature properties of sodium soap grease [12]. 5. mixed soap grease it is generally manufactured by saponifying the fatty material with mixed alkalis derived from metals. one of the soaps usually predominates and determines the general character of the greases while the other modifies the structure in some way. this results, for example, in changes in texture and improved mechanical stability [13]. 6. complex soap grease it is formed when two dissimilar acids are attached to the same metal molecules, thus restricting complexes to only polyvalent metals [14]. there are several types of complex grease, such as, calcium complex grease, aluminum complex grease, and lithium complex grease. 7. non soap grease two non-soap greases are present. one is organic, the other inorganic. a. polyurea it is the most important organic non soap thickener. it is a low-molecular weight organic polymer produced by reacting amines with isocyanates, which results in an oil soluble chemical thickener. b. organo – clay it is the most commonly used inorganic thickener. its thickener is modified clay, insoluble in oil in its effect of additives on the properties of different types of greases 14 ijcpe vol.14 no.3 (september 2013) -available online at: www.iasj.net normal form, but through complex chemical processes, converts to platelets that attract and hold oil. organo – clay thickener structures are amorphous and gel-like rather than the fibrous, crystalline structures of soap thickeners. this grease has excellent heat resistance since clay does not melt. experimental wok the greases used in the experimental work are produced in al-daura refinery, which are; lithium soap grease, calcium soap grease, and sodium soap grease. table (1) shows the main characteristics of these greases used in the experimental work according to astm methods. additives which were used in the experimental work, extreme pressure additive, graphite, molybdenum disulfide mos2, carbon black, and corrosion inhibitor. all these additives were from al-daura refinery have the properties shown in tables (2), (3), and (4). oil-base stocks have been selected on the basis that they are widely used in commercial production of lubricating oil and greases. experimental procedure a. four ball welding test this test aimed, to find the force required to cause metal surfaces to weld after subjected to friction under high pressure, using lubricating grease to be tested. astm d-2596 method was used, with the apparatus four-ball extreme pressure lubricant tester. the ball pot was filled completely with the grease to be tested. the three steel test balls were embedded in the grease. the lock ring was carefully placed over the three balls. the weight tray and weights were placed on the horizontal arm in the correct notch for a base test load of 80 kgf. b. four-ball wear test the aim of this test is to find the ability of metal surfaces to wear after rubbing one another, using lubricating grease in certain temperature and specific load. astm d-2266 method was used, with the apparatus four-ball wear tester. a small amount of the grease was placed in the ball cup sufficient to the fill the void between the three balls tobe inserted in the ball cup and the balls were locked in position into the ball cup. the diameter of the affected areas caused by friction was measured using the provided microscope c. copper corrosion test the aim of this test was to cover the detection of the corrosiveness to copper of lubricating grease. astm d4048 method was used, with instrument for copper strip corrosion measurement. the surface of the sample was pressed into contact with copper strip and leveled with the spatula. the corrosiveness was reported in accordance with one of the special classifications. d. dropping point test this test covers the determination of the dropping point of lubricating grease; this point is being the temperature at which the first drop of material falls from the cup. so the dropping point is the temperature, at which the grease passes from a semi solid to a liquid state, under the conditions of the test. astm d-2265 method was used. dropping point assembly manufactured by koehler instrument used as a tester. e. work penetration test this test measured the consistency of lubricating grease by penetration of the standard cone. astm d-217 method was used, with the apparatus of penetration tester manufactured by the muhannad a.r. mohammed -available online at: www.iasj.net ijcpe vol.14 no.3 (september 2013) 15 nomalanalis company, france. a penetrometer shall be capable of indicating depth in tenths of a millimeter, since cone shaft rapidly released, and allowed to drop for 5.0 0.1 sec. the penetration was read and recorded from the indicator results and discussion the effect of concentration of additives on the bearing pressure, wear resistance, drop point, and worked penetration were discussed. 1effect of extreme pressure (ep) additive: extreme pressure additive was added to achieve good properties of load carrying to the lubricating grease. fig.(1) shows the effect of wt.% of extreme pressure additive on four-ball welding test at different types of grease. it is clear from this figure, that the addition of 1 % of ep, the lithiumcalcium has 800 kgf extreme pressures which are higher than the other and equal to the extreme pressure of lithium grease, since less frictional heat is generated and the potential for severe welding is reduced. the addition of 1.5% wt. of extreme pressure additive shows a remarkable change in characteristics, after this percentage of addition, the load remained almost constant. fig. (2) shows the effect of extreme pressure additive on wear test for different types of grease. the addition of 1% of ep to each type of grease shows that the wear reduction using lithium grease is better than using the other greases. also, the calcium, sodium grease were less effected by ep. extreme pressure additive react with the surface to form protective films which prevent metal to metal contact and the consequent scoring or welding of the surfaces. fig. (3) shows that the drop point temperature remained constant despite the increase in additive in lithium grease. this is a good indicator that the other characteristics remained unchanged in this type and the other types of grease, except for calcium grease where drop point decreased slightly because of soap fiber length that holds the structure of the grease [11]. fig.(4) shows that the addition of ep has a slight increase in worked penetration for all types of greases means that the basic texture of greases do not change significantly, shear stability is maintained. 2effect of graphite additive: graphite is physical additive. it is one of the most widely used fillers and that found applications in numerous types of lubricating greases [11]. figure (5) clarifies that the addition of graphite will increase the bearing load for all types of greases. since the load increased from 400 kgf to 800 kgf in lithium grease, from 160 kgf to 400 kgf in calcium grease, from 250 kgf to 800 kgf in sodium grease and from 620 kgf to 800 kgf in lithiumcalcium grease. the best additive percentage ranges was between 3.0 – 5.0 %. the addition of graphite will decrease the wear in all kinds of greases as shown in fig. (6), the response of lithium grease to wear resistance additive is higher than that in calcium grease and lithium-calcium, thus there is no need to mix these greases for wear resistance purposes. the best percentage of added graphite was 5 % for lithium grease, 15 % for calcium, sodium, and lithium – calcium grease the lithium grease has a higher drop point from other types of other greases as shown in fig. (7), and till the percentage of added graphite reached 15 %, and so did the other greases, which means that adding graphite does not change the structure of grease. the work penetration has shown in fig. (8), a little change when graphite is effect of additives on the properties of different types of greases 16 ijcpe vol.14 no.3 (september 2013) -available online at: www.iasj.net added, since the filler has a little influence upon the consistency of the product. as the amount of filler is increased, the effect becomes evident [11]. 3effect of molybdenum disulfide additive: it is noted from fig. (9) that when adding different percentages of molybdenum disulfide (1 – 15 %) to lithium, calcium, sodium, and lithiumcalcium grease to become suitable to prevent seizures under conditions of high temperatures, heavy loading or extended periods of operation, fourball welding reading will increase. the load carrying using molybdenum disulfide is higher due to their structure, since this additive has a "layer lattice'' structure in which the atoms in each layer or "basal plane'' are located at the corners of regular hexagons the addition of mos2 will decrease the wear in all types of greases used as shown in fig. (10), this makes the molybdenum disulfide more economical than graphite, since it is more efficient in wear test, as shown in fig. (11). there is no change in drop point for all types of grease with the addition of molybdenum disulfide as shown in fig. (12), while the work penetration was increased which clarified clearly in fig. (13). 4carbon black additive: carbon black can be classified as a physical type of additive which is selected as alternative for molybdenum disulfide and graphite on the basis of availability and low cost as factors contributing in the extensive use of this additive. the best addition percentage ranges of carbon black is between (2.5 – 10 %) as shown in figures (14), (15), (16), and (17) for four-ball welding, wear, drop point, and worked penetration test. it was noted from this additive in the selected range the followings: 1maximizing the heavy load carrying, i.e. welding. 2minimizing the wear effect. 3increasing the dropping point. 4a little effect upon consistency, thus it is safe to be used. 5effect of corrosion inhibitor additive: one of the most important additives is the corrosion inhibitor. it can be classified as a chemical additive type. its effect is measured by observing a cupper strip using a methodology set by astm. there are three cases to recognize the corrosion on this strip according to the blackening of the strip. this additive is added to prevent corrosion in a grease medium. the effect of this additive is clearly shown in figure (18). the effect of addition of this additive starts after adding 1 % to lithium-calcium grease where the strip becomes bright, while calcium grease is basically, without additive, shows a bright strip since calcium base lubricating grease is water repellant it has been supposed that they do started after adding 2 %. in the case of sodium grease, the effect appears at 3 %. to insure that this additive does not have any negative effect on grease, the drop point and worked penetration is measured for each addition as shown in figures (19), and (20). lithium, sodium, and lithium-calcium greases proved that the drop point does not change at any percent of addition, while calcium showed a slight transition because its fiber length is short [11]. muhannad a.r. mohammed -available online at: www.iasj.net ijcpe vol.14 no.3 (september 2013) 17 table 1, characteristics of used lubricating greases specifications lithium soap calcium soap sodium soap worked penetration (mm -1 ) 270 273.8 334.2 drop point (°c) 202 100 150 copper corrosion test (24 h at 100°c) 2a 1a 2a four-ball weld load (kgf) 400 160 250 four-ball wear test (wear scar diameter mm) 0.31 0.65 0.566 texture soft soft fibrous color brown yellow green table 2, properties of hitec 343 extreme pressure additive [19] property specification appearance bright clear and amber liquid viscosity @ 100 °c. mm 2 /s 9.0 density @ 15.6°. g/ml 1.082 phosphorus. %wt 1.17 sulfur. %wt 36.1 table 3, properties of graphite additive [18] property specification formula c color black crystalline form hexagonal melting point (°c) 4200 table 4, properties of molybdenum disulfide additive [18] property specification formula mos2 color black crystalline form hexagonal melting point (°c) 1185 fig. 1, effect of ep additive on four ball welding test at various types of greases fig. 2, effect of ep additive on four ball wear test for various types of greases fig. 3, effect of ep additive on drop point test at various types of greases effect of additives on the properties of different types of greases 18 ijcpe vol.14 no.3 (september 2013) -available online at: www.iasj.net fig. 4 effect of ep additive on work penetration test at various types of greases fig. 5, effect of graphite on four ball welding test fig. 6, effect of graphite additive on four ball wear test fig. 7, effect of graphite percent of additive on drop point test fig. 8, effect of graphite additive on work penetration test fig. 9, effect of molybdenum disulfide percent additive on four ball welding test muhannad a.r. mohammed -available online at: www.iasj.net ijcpe vol.14 no.3 (september 2013) 19 fig. 10, effect of molybdenum disulfide percent additive on wear test fig. 11, effect of graphite and molybdenum disulfide percent additive on wear test in lithium grease fig. 12, effect of molybdenum disulfide on drop point test fig. 13, effect of molybdenum disulfide on work penetration test fig. 14, effect carbon black additive on four ball welding test fig. 15, effect carbon black additive on four ball wear test effect of additives on the properties of different types of greases 20 ijcpe vol.14 no.3 (september 2013) -available online at: www.iasj.net fig. 16, effect carbon black additive on drop point test fig. 17, effect carbon black additive on work penetration test figure (18) effect of corrosion inhibiter additive on copper strip corrosion test fig. 19, effect of corrosion inhibiter additive on drop point test fig. 20 effect of corrosion inhibiter additive on work penetration test conclusions the following conclusions are drawn from this research: 1improvement of grease to withstand high pressure and having less wear is much affected by the type and percentage of additive used. the addition of extreme pressure, graphite, molybdenum disulfide, and carbon black additive are 1.5, 3, 1, and 2.5 % respectively in all types of greases used in this study. 2when adding corrosion inhibitor to calcium grease, the test strip did not show any sign of corrosion. this is an indicator that calcium grease is muhannad a.r. mohammed -available online at: www.iasj.net ijcpe vol.14 no.3 (september 2013) 21 water repellant and does not need the addition of corrosion inhibitor. the effect of adding corrosion inhibitor to lithium-calcium grease started to be noticed at 1 %, 2 % at lithium grease and 3 % at sodium grease. 3lithium grease has many good properties such as load carrying, high temperature performance and shear stability, thus it is considered valuable grease and very commonly used in most parts of the world. 4when mixing lithium grease with calcium grease and comparing it with lithium grease, it is found that it has slightly better properties than lithium grease. this does not justify leaving the use of lithium grease. that is true for economic reasons due to the need for mixing equipment and electrical power and consequently a higher cost is incurred. references 1i. couronne, d. mazuyer, p. vergne, n. truong-dinh and d. girodin, 2003, “effect of grease composition and structure on film thickness in rolling contact”, lmc, i.e.t., umr cnrs/insa 5514, 20 avenue einstein, 69621 villeurbanne cedex france. 2theo mang and wilfried dresel, 2007, ''lubricants and lubrication'', wiley-vch, second edition p.88. 3gwidon w. stachowiak and andrew w.batchelor, 2007,” engineering tribology”, butterworth heineman. 4edward brunet, jr., p.e., pdh engineer.com, course no. ma2003, lubrication-grease. 5mccarthy, p.r., january 1972, nasa symposium, cleveland. 6g.d.hobson, 1975, “modern petroleum technology”. 7f.t. comphell, 1990,”ulmann’s encyclopedia of industrial chemistry”, a3. 8j.f. hulton, 1996, “the principle of lubricant”. 9t.singh, 1990, tribology international, 23. 10c.j. klenke, 1990, tribology international, 42. 11c.j. boner, 1954,”manufacture application of lubricating greases”, reinhold publishing corp. 12handbook of petroleum products analysis, chapter 13, grease. 13j. denis, j. briant, and j.c. hipeaux, 1998, “lubricant properties analysis and testing”. 14mcbai, j.w. and bolduam, 1943, j. am. chem. soc., 56. 15www.lubrizol.com. 16hurguth laboratories, inc., tribology studies lubrication and materials. 17e.r. brithwaite, 1967 “lubrication and lubricants”, elsevier publishing company, amsterdam. 18robert h.perry, “chemical engineer’s hand book “, 7 th edition, 1997. 19enthy1 petroleum additives limited , london road , bracknell, berkshire , england .report no.442/1,1998. 20x. lederer, us patent 1936623, 28 november, 1993.21calhoun, s. fred, report no. 62 – 2752 rock island arsenal, aug. 15, 1962: ad 291052. 21calhoun, s. fred, report no. 62 – 2752 rock island arsenal, aug. 15, 1962: ad 291052. 22tarunendr singh, ''tribochemistry ep activity assessment of mos complexes in lithium base greases'', bharat petroleum corporation limited, r & d center, india, 2000 iraqi journal of chemical and petroleum engineering vol.15 no.4 (december 2014) 18-18 issn: 1997-4884 preparation of pvc hollow fiber membrane using (dmac/acetone) dr,fawziea m. hussein a , dr,amel s. merzah b and zaid w. rashad c a air conditioning engineering dept., technical college-baghdad, foundation of technical education b material engineering dept., technical college-baghdad, foundation of technical education c chemical engineering dept., college of engineering, university of baghdad abstract membrane manufacturing system was operated using dry/wet phase inversion process. a sample of hollow fiber membrane was prepared using (17% wt pvc) polyvinyl chloride as membrane material and n, n dimethylacetamide (dmac) as solvent in the first run and the second run was made using (dmac/acetone) of ratio 3.4 w/w. scanning electron microscope (sem) was used to predict the structure and dimensions of hollow fiber membranes prepared. the ultrafiltration experiments were performed using soluble polymeric solute poly ethylene glycol (peg) of molecular weight (20000 dalton) 800 ppm solution 25 °c temperature and 1 bar pressure. the experimental results show that pure water permeation increased from 25.7 to 32.2 (l/m 2 .h.bar) by adding acetone to the dope solution, while rejection decreased from 91.8 to 63.2%. keywords: polyvinyl chloride, (dmac/acetone) of ratio 3.4, ultrafiltration introduction membrane technology is presently an established part of several industrial processes. well known is its relevance in the food industry, in the manufacture of dairy products as well as in the automotive industry for the recovery of electro-painting baths and wastewater treatment. membranes make possible the water supply for millions of people in the world and care for the survival of the unnumerable people suffering from kidney disease. the chemical industry is a growing field in the application of membranes, which, however, often requires membrane materials with exceptional stability [1]. ultrafiltration (uf) membranes are porous membranes with pore size ranging from 5 to 50 nm. the term ultrafiltration has been introduced to discriminate the process whose nature lies between nanofiltration and microfiltration [2]. three modules of ultrafiltration can be obtained flat sheet, tubular and hollow fiber. for the hollow module the membrane is essentially a fiber with a hollow space (cavity) inside. a bundle of hollow fibers are assembled to gather in a module, with the free ends potted into a head plate the hollow fiber configuration is the favorite choice for modules in membrane separation because of the hollow fiber membranes having three major advantages over flat sheet membranes; hollow fibers have much larger ratio of membrane area to unit volume and hence higher productivity per unit volume of membrane module. iraqi journal of chemical and petroleum engineering university of baghdad college of engineering preparation of pvc hollow fiber membrane using (dmac/acetone) 82 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net there is self supporting that can be back-flushed for liquid separation. they have good flexibility in operation. therefore, the key properties determining membrane performance are high selectivity and fluxes, good mechanical strength, good chemical resistance, thermal stability under operating conditions, low fouling tendency, good compatibility with the operation environment, cost effective and defect free production [3]. reverse osmosis and ultrafiltration membranes have been employed for the treatment of a variety of liquids ranging from seawater, to wastewater, to milk and yeast suspensions. each liquid varies in composition and in the type and fraction of the solute(s) to be retained by the membrane. complicating factors include the presence of substances such as, for example, oil in seawater and waste water. the presence of the oil normally necessitates an additional pretreatment step as well as further complicating the fouling process. the presence of humic acids in surface water and waste water also needs special attention. the fouling phenomena, the preventive means (i.e. pretreatment), and the frequency and type of membrane cleaning cycle are all dependent on the type of liquid being treated [4]. these two processes, ultrafiltration (filtration to 10 angstroms for dissolved organic removal) and reverse osmosis (filtration to 5 angstroms for dissolved organic and inorganic removal) are relatively new to the soft drink industry. several reverse osmosis systems have been installed over the last five years and a few ultrafiltration units have been installed where only filtration and organic removal have been necessary [5]. objective study the effect of using double solvent on performance and structure of hollow fiber membranes by using membrane performance system and scanning electron microscope (sem). membrane performance the performance of a membrane is defined in terms of two simple factors, flux and retention or selectivity. flux or permeation rate is the volumetric (mass or molar) flow rate of fluid passing through the membrane per unit area of membrane per unit time [5]. … (1) where q is the volumetric permeate flow rate (lh -1 ), a is the surface area of hollow fiber membranes (m 2 ) and δp is the transmembrane pressure (bar). selectivity is a measure of the relative permeation rates of different components through the membrane while retention is the fraction of solute in the feed retained by the membrane. ideally a membrane with a high selectivity or retention and with a high flux or permeability is required although typically attempts to maximize one factor are compromised by reduction in the other. the simplest way to express the solute rejection characteristic of hollow fiber membrane is through observed/apparent rejection defined as the following relation [5]. ( ) ( – ) … (2) where cp and cf denote concentration of permeate and concentration of feed/bulk solution respectively and both can be measured. porosity measurements the membrane porosity, εm, can be defined as the volume of the pores divided by the total volume of the membrane. briefly, hollow fibers, not previously treated with the glycerol solution, were dried and weighed with fawziea m. hussein, dr,amel s. merzah and zaid w. rashad -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 83 a precision balance. the overall porosity was calculated as shown in table (2) according to the following formula [6]: ( ) ( ) … (3) where is the fiber density, is the pvc density. the fiber density was calculated from the mass and volume ratio: ( ) … (4) where l is the fiber length, m its mass, id and od the inner and the outer diameter, respectively. experimental work the polymeric membranes production is a complicated process since it involves many steps namely; material selection, drying process, dope solution preparation, casting or hollow fiber spinning, phase inversion process, and post treatment. materials 1. polyvinyl chloride (pvc) powder as a membrane material, with k value 67, supplied by gerhard buchmann kg tuttlingen/germany. n, n dimethylacetamide (dmac) supplied by seelze 2. hannover/germany was used as a single solvent. n, n dimethylacetamide and acetone of purity 99.8% were used as double solvent to prepare polymer solution. 3. poly ethylene glycol of molecular weight (mw 20000 dalton) supplied by merck was used as a reference solution for characterizing the hollow fiber membranes performance. 4. distilled water was used as internal coagulation fluid (bore fluid) and tap water as external coagulation one. dope solution dope solution of 100g was prepared for both experiments, pvc powder which dried in an oven for 6 h at 70 °c to remove moisture content then dissolved in single solvent n, n dimethylacetamide (dmac) (17/83 wt/wt pvc/dmac), for the second experiment pvc powder dissolved in a mixture of two solvents dmac and acetone at a ratio of 3.4 w/w keeping the ratio of(pvc/dmac and acetone) 17/83 wt/wt. spinning process spinning process is a physical process, which involves the extrusion of a polymer solution through an annular spinneret (inner diameter 1mm, outer diameter 2mm) to form a hollow fiber. the dope solution entered the side opening of the spinneret no. 5 as shown in fig. (1) under an extrusion pressure of 0.1 bar of nitrogen, distilled water was used as an internal coagulant which pumped to the tube of the spinneret at a water flow rate (0.15 ml/s).the nascent hollow fiber membranes passed through a certain air gap 5 cm distance before entering the external coagulant bath (tap water at 25 °c). preparation of pvc hollow fiber membrane using (dmac/acetone) 84 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net fig. 1: schematic diagram and manufacturing unit of the spinning system: 1nitrogen tube. 2-pressure valve. 3-pressure gauge. 4-dope solution column. 5dope solution valve. 6-spinneret. 7-bore fluid container. 8-bore fluid pump. 9-air gap length. 10-movable wheel. 11-coagulation tank. 12-take-up unit. 13-hollow fiber membranes. 14hollow fibers reservoir container (fill with water) post treatment after the spinning of hollow fiber, the prepared membranes were put in a water bath at room temperature for at least one day to remove the residual solvent completely without further drying. after that they were kept in an aqueous solution of 25% glycerol (by volume) for 48 hour to avoid collapse of its porous structure and dried in air at room temperature. equipments the cross sections and dimensions (inner diameter, outer diameter, and thickness) were determined using scanning electron microscope (tescan performance in nano space version 3.5.12.0). the feed and permeate solute concentrations were determined by using uv spectrometer (thermo electric/genesys 10uv). results one of the important goals in membrane technology is to control membrane structure and thus membrane performance (flux and rejection). membrane with higher flux leads to higher productivity and lower capital costs whereas membrane with higher rejection leads to higher recovery and lower power costs. [5] membrane dimensions inner diameter, outer diameter and thickness were measured using sem for the two system membranes single solvent (ss) and double solvent (ds) as shown in table (1). table 1: membrane dimensions membrane system inner diameter (mm) outer diameter (mm) average thickness (mm) (ss)system membrane 0.80 1.10 0.15 (ds)system membrane 0.68 0.97 0.14 table 2: porosity of hollow fiber membranes prepared according to equation (3). membrane system porosity % (ss)system membrane 21.6 (ds)system membrane 44.6 porosity % doubled by adding small amount of acetone to the dope solution which can be observed from fig. (2). fawziea m. hussein, dr,amel s. merzah and zaid w. rashad -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 85 fig. 2 sem surface images (a) single solvent (ss) (b) double solvent (ds) effect of using double solvent on morphology and flux of hollow fiber membrane solutions using low solubilityparameter solvents, such as acetone are generally not appropriate. such casting solutions precipitate slowly and give relatively nonporous membranes. small amounts of these solvents may be added as casting solution modifiers [7]. however, pvc is insoluble in pure acetone [8]. acetone acts as a non-solvent additive. it has been reported that the properties of polymer membranes could be improved by introducing non-solvent additives in the polymer solution [9]. fig. 2 shows the structures of crosssectional sem pictures of hollow fiber pvc membranes. in fig. (2) a-fiber without additives has a wide finger-like structure while fig. (3) bfiber with acetone additive show that the fingerlike structure became thinner. several authors reported that appropriate amount of non-solvent additives enhanced the formation of macro voids [9]. fig. 3 sem observations (a) single solvent (ss) (b) double solvent (ds) as the macro-porous of the membrane increase the pure water permeation flow (pwpf) increase and rejection decrease as shown in table (3), pure water permeation fluxes (pwpf) were obtained from equation (1). preparation of pvc hollow fiber membrane using (dmac/acetone) 86 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net table (3): pure water permeation flow and rejection of peg (20000 d) for pvc hollow fiber membrane at feed flow rate 10 l/h. membrane system polymer concentration (wt. %) pwpf jpwpf rejection r% (ss) system 17 25.7 91.8 (ds) system 17 32.2 63.2 a feed solution of 800 ppm peg (20000 d) was used to measure permeability and rejection of the prepared hollow fiber membranes. the feed flow rate was 10 l/h fig. 3 and fig. 4 shows the permeation flux decreased with time at operating temperature 25 °c and 1 bar pressure for horizontal hollow fiber module. flux decreased according to accumulated solute (peg). fig. 4 permeation flux of solution 800 ppm peg (20000 da) for single solvent (ss) system. fig. 5 permeation flux of solution 800 ppm peg (20000 da) for double solvent (ds) system. conclusions hollow fiber ultrafiltration membranes were prepared using two solvents system, single solvent (ss) and double solvent (ds). according to the results, the following facts can be obtained: high polymer concentration (17 wt. %) might result in a hollow fiber membrane with a dense skin layer in single solvent system. sem pictures illustrated that pvc membrane morphology changed from wide finger-like structure through a thin finger-like structure with some voids. macro-porous membranes were obtained in double solvent system. according to the macro-porous, permeability was increased and rejection decreased. nomenclature symbol definition unit ρ fiber fiber density g/ cm 3 εm membrane porosity -- j pure water flux l/(m 2 ·h·bar) ρ pvc pvc density g/ cm 3 r rejection -- a surface area of hollow fiber m ² ∆p transmembrane pressure bar q volumetric flow rate l/h 0 10 20 30 0 100 200 p e rm a e ti o n f lu x l/ m 2 .h .b a r time (min.) 10 l/h 0 10 20 30 40 0 100 200 p e rm a e ti o n f lu x l/ m 2 .h .b a r time (min.) 10 l/h fawziea m. hussein, dr,amel s. merzah and zaid w. rashad -available online at: www.iasj.net ijcpe vol.15 no.4 (december 2014) 87 references 1s. p. nunes and k.-v. peinemann (eds.), (2001),"membrane technology in the chemical industry," wiley-vch, , 2-7. 2seeram ramakrishna, zuwei ma, and takeshi matsuura (2011), "polymer membranes in biotechnology," imperial college press,3-5. 3 m. i. mustaffa et al, (2002), " study on the effect of polymer concentration on hollow fiber ultrafiltration membrane performance and morphology," membrane research unit, faculty of chemical & natural resources engineering, universiti teknologi malaysia, locked bag 791, 80990 johor bahru, malaysia 4m. f. a. goosen et al,(2004), "fouling of reverse osmosis and ultrafiltration membranes: a critical review", marcel dekker, vol. 39, pp 2261-2298. 5mohd idham bin mustaffar, (2004), " development of asymmetric polyethersulfone hollow fiber ultrafiltration membrane for cyclodextrin separation", universiti teknologi malaysia. 6wang k. y., chung t. s.,(2008), “hydrophobic pvdf hollow fiber membrane with narrow pore size distribution and ultra-thin skin for the fresh water production through membrane distillation” chemical engineering science, 63, p 2587-2594. 7nabil k.t.,(2010), "preparation and characterization of pvc hollow fiber membrane for ultra filtration application," m. tech. in material engineering technology, technical collage baghdad, december. 8ari l. horvath, (2006) "solubility of structurally complicated materials," j. phys. chem. ref. data, vol. 35, no. 1, 77-92. 9zhen-liang xu and f. alsalhy qusay, (2004), " polyethersulfone (pes) hollow fiber ultrafiltration membranes prepared by pes/non-solvent/nmp solution," journal of membrane science 233, , 101–111 10zaid w. rashad, (2012), "operating system for preparation hollow fiber membranes using for water treatment" h.d. tech in material engineering technology, technical collage baghdad. preparation of pvc hollow fiber membrane using (dmac/acetone) 88 ijcpe vol.15 no.4 (december 2014) -available online at: www.iasj.net available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.23 no.4 (december 2022) 33 – 41 eissn: 2618-0707, pissn: 1997-4884 corresponding author: name: ammar s. abbas, email: ammarabbas@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. textural properties characterization for nax and fex zeolites by nitrogen adsorption-desorption technique sanarya k. kamal and ammar s. abbas chemical engineering department, college of engineering, university of baghdad, baghdad, iraq abstract the zeolite's textural properties have a significant effect on zeolite's effectiveness in the different industrial processes. this research aimed to study the textual properties of the nax and fex zeolites using the nitrogen adsorption-desorption technique at a constant low temperature. according to the international union of pure and applied chemistry, the adsorption-desorption isotherm showed that the studied materials were mixed kinds i/ii isotherms and h3 type hysteresis. the brunauer-emmett-teller isotherm was the best model to describe the nitrogen adsorption-desorption better than the langmuir and freundlich isotherms. the obtained adsorption capacity and brunauer-emmett-teller surface area values for nax were greater than fex. according to the kelvin equation, barrett, joyner, and halenda model was used to determine pore size distribution, diameter, and average pore volume for the selected zeolites. the pore size distribution for nax was wider than fex zeolites, the pore diameter for nax was less than fex, and the average pore volume for fex was greater than the value of nax average pore volume. the comparative study was carried out with the previous studies, and the comparison showed that the textual properties of the modified zeolites agreed with other studies. keywords: ion-exchange; mesoporous; pore size distribution; surface area; pore diameter; isotherms; average pore volume. received on 15/06/2022, accepted on 10/09/2022, published on 30/12/2022 https://doi.org/10.31699/ijcpe.2022.4.5 1introduction a zeolite mineral is a crystalline substance made of interconnected tetrahedra, each of which has four o atoms around a cation. zeolite system has open voids in the shape of channels and cages [1]. zeolite type x are microporous crystalline minerals composed of oxygenbonded sio4 and alo4 tetrahedra. the negative charge in the zeolite framework is balanced by exchangeable cations [2]. using zeolites is expanded by modifying them. ionexchange reactions can dramatically alter the surface characteristics of zeolites when using cationic surfactants [3], and it is essential to adjust ion-exchange materials' chemical structure and content using proper pretreatment. to enhance ion-exchange capabilities and obtain a porous substance with a high absorption capacity, it must also have a significant specific area, displaying a porous structure with micropores. water and exchangeable cations may fill zeolite's crystal and porous form, which has a particular pore size [4]. zeolites are widely employed in a wide range of applications; they can be used as adsorbents [5-7], sorbents for dyes [8,9], heavy metals [10], and other contaminants in wastewater and natural water [11], molecular filter [12], ion-exchange compounds [13,14], catalyst [15-17]. the textural properties of zeolites significantly affect their effectiveness in industrial processes. thus, studying the porous materials' textual properties by the nitrogen adsorption-desorption technique is essential. the textural properties include the pore size distribution, surface area (sbet), pore diameter (dbjh), and average pore volume (vp). the gas adsorption process is a typical process for describing porous solids. the nitrogen adsorptiondesorption method measures materials' sbet and pore size distribution [18,19]. adsorption is a surface process that defines the interaction between two distinct phases that results in the formation of an interface layer by transferring a molecule from a fluid bulk (liquid or gas) (adsorbate) to a solid surface (adsorbent) [20,21]. the gas adsorbed in a solid depends upon the surface area where the larger surface area of the adsorbent will be active site, so the rate of adsorption increases, temperature, the pressure of the gas, and the gas nature. the adsorption isotherm is the relationship between the adsorbate in the liquid phase and the adsorbent's surface at equilibrium at a specific temperature [22,23]. the international union of pure and applied chemistry (iupac) divides adsorption isotherms into six types depending on the shape of the isotherm of relative pressure and the gas adsorbed onto a solid surface [24]. the first category i isotherms shows monolayer adsorption. pore size is not significantly more significant than the molecular diameter of the adsorbate molecules. the adsorption increases with pressure until it reaches saturation. hence, no further adsorption occurs regarding the second category ii, often known as macro-porous http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:ammarabbas@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2022.4.5 s. k. kamal and a. s. abbas / iraqi journal of chemical and petroleum engineering 23,4 (2022) 3341 34 adsorbents, which have a wide variety of pore diameters, obtained when the bilayer is created after the monolayer is complete. the tri-layer is generated after the bilayer is full. the third category (iii), the adsorption isotherm, is obtained when the monolayer formation is followed by multilayer the adsorption quantity increases virtually exponentially. in the fourth category (iv), the lower pressure region is like the category ii isotherm, which clarifies the formation of monolayer followed by multilayer on the pore wall much more comprehensive than the sorbate molecular diameter (mesoporous). the fifth category (v) adsorption isotherm is like category iv when intermolecular attraction effects are strong, and adsorption occurs in pores. finally, the sixth category (vi) isotherm signifies layer-by-layer adsorption on a nonporous surface with substantial uniformity. the capacity of each adsorbed layer is represented by the step height, while the step sharpness depends on the system and temperature [22,25]. carbon dioxide, argon, and nitrogen are gases that may be used for adsorptiondesorption (n2). n2 (measured at 77.35 k) has remained extensively familiar and regarded as friendly commercial apparatus between these many gases and vapors existing and might be employed as adsorbate [24]. various adsorption models are used to describe adsorption isotherms experimental data for different porous materials [18, 26-30]. this research investigated the textural properties of nax zeolite, and its modified version by fe (ii) exchanged (fex) using n2 adsorption-desorption technique. the obtained data would be fitted with different adsorption isotherms. the brunauer-emmettteller (bet) would obtain the sbet. finally, the barrett– joyner–halenda (bjh) will get pore size distribution, dbjh, and vp. the obtained results will be compared with the previous studies. 2experimental 2.1. preparation of fe (ii) ion-exchanged zeolite (fex) nax zeolite (commercial grain) was crushed and then sieved with 200 mesh strainers to homogenize the size. nax zeolite containing a high sodium weight percentage (14.719%) was exposed to an ion-exchange procedure with ferrous sulfate heptahydrate (feso4∙7h2o, india) to replace the sodium from nax zeolite. 5 g of dried nax zeolite was added to 100 ml of a 0.319 m solution and maintained at controlled temperatures of 80°c with constant stirring (300 rpm) for 8 hours. then exchanged nax zeolite samples were taken from the ion-exchanged solution and filtered, washed several times with distilled water to remove the fe (ii), which had not been exchanged, and taken to an oven for drying overnight at 60 °c overnight. the sample was calcined in a furnace at 550 °c for 3 hours; then, it was left to cool inside in a desiccator until it reached room temperature. the concentration of fe (ii) in the exchange solution was measured using atomic absorption spectrophotometry (varianaa240fs, australia), and the amount of exchange fe (ii) was determined. the atomic absorption spectrophotometry was tested at north gas company (ministry of oil, iraq). 2.2. adsorption-desorption tests n2 adsorption-desorption occurred over samples of nax zeolite (0.0779 g), and fex zeolite (0.2047 g) were measured using the micromeritics asap 2020 instrument. all tests were accomplished at the petroleum research and development center, ministry of oil (iraq). after performing each measurement three times, the average values of the obtained data were calculated, recorded, and afterward utilized in the investigation of the isotherm models. after that, measurements were taken to determine the sbet, particle size distribution, pore diameter, and vp values. 2.3. langmuir isotherm model langmuir explained the isotherm model, primarily designed to describe gases adsorbed to solid and obtained in 1916 [31]. langmuir model assumes that the adsorption consists of a monolayer at the surface, and no further adsorption occurs. the adsorbent's surface is homogenous [20,32]. the langmuir isotherm is expressed as in eq. (1). 1 m m l p p q q q k   (1) kl can be associated with the difference in the adsorbent's porosity and suitable area, indicating that a higher pore volume and surface area will result in a higher adsorption capacity [33]. a plot of p/q against p should give a straight line with slope 1 m q and intercept 1 m l q k and find the langmuir constant and the monolayer maximum sorption capacity [31]. 2.4. freundlich isotherm model freundlich isotherm is an empirical equation published in 1906 and extensively applied to model the multilayer adsorbed on heterogeneous surfaces at a specific temperature [34]. freundlich model equation represents in eq. (2) [35]. 1 f logq logk logp n   (2) 2.5. bet isotherm model a significant application of the bet isotherm is the surface area measurement for solid materials. the surface area can be approximated by utilizing the bet equation derived from a specific region of a gas adsorption isotherm. after the bet theory's publication, this area on s. k. kamal and a. s. abbas / iraqi journal of chemical and petroleum engineering 23,4 (2022) 3341 35 the isotherm is where gas monolayers are thought to develop [36]. the bet theory relies significantly on the concept that the surface of a substance can play presenter to the adsorption of gases. the bet study is predicated on the adsorption isotherms of nonreactive gas molecules, such as nitrogen or argon, at a pressure range that encompasses the monolayer coverage of molecules [37]. an example of a theoretical equation that can compute the surface area of gas-solid equilibrium systems is the bet isotherm, which can be found [38]. 1 1 1 o o m m o p c pp q c p q cp q p                       (3) where c relates to the difference between the heat of adsorption in the first layer(e1) and the heat of vaporization (el)= 1exp( )l e e rt  [25], the nitrogen adsorption data obtained in the current investigation could be used only using a limited range of relative pressures (0.05-0.3) or, in many cases, up to 0.4 [39]. in that state, the linear plot between the term 1 o o p p p p q                    and relative pressure o p p       allows determining qm and c from intercept and slop. after calculating these values, the total surface area (st), may be computed using the value of qm [39]. 2.6. determination of the total surface area the total surface area of samples was verified using eq. (4) [40]. m m t q na s v  (4) in the adsorption, the n2 molecule cross-sectional area equals 0.1620 nm2, nitrogen absorbed molar volume (22.414 l/mole). 2.7. bjh pore diameter and volume (bjh) is a method used for measuring pore size distribution and pore volume from experimental data. using the data from the n2 adsorption-desorption isotherm at 77.35 k, it is possible to determine both the dbjh and the vp of the adsorbent. bjh improved in 1951 [41] by imagining that all pore shapes are cylindrical with nonintersecting and open ends. bjh model presumed that the pore radius was equal to the combination of the kelvin radius and the thickness of the adsorbed layer, as found in the eq. (5) [42]. cos ln ( ) o p c p rt r t         (5) the halsey equation may calculate the thickness of the adsorbed layer remain on the pore walls as shown in eq. (6) [43]. 0.333 5 3.54 ln o t p p                (6) 3results and discussion the findings on n2 adsorption-desorption were utilized to determine the kind of the isotherm and the nature of the adsorption process for chosen zeolites. fig. 1 showed the n2 adsorption-desorption isotherms on the nax and fex zeolites surfaces. the curves displayed that the micropore filling was noticed at a proportionally low pressure owing to the narrow pore width and the excellent adsorption potential, the phenomenon refers to the category i isotherm for the microporous materials. the adsorption increases with pressure until it reaches saturation. whereas at p/po ≥ 0.8 suggests pore expansion; mesopore adsorption played a role in the adsorption process, the phenomenon refers to category ii isotherm characteristics. the nax had micropores and mesopores, but following the ion-exchange, the volume of n2 adsorbed at low p/p° values dropped, implying a reduction in available microporosity. the findings indicated that the adsorption isotherms combined the kinds i/ii. in fig. 1 (a), the quantity of n2 absorbed by nax zeolite was 230.11 cm3/g, while the fex only absorbed 184.84 cm3/g, as displayed in fig. 1 (b). according to the iupac category, the nax and fex zeolites, mesoporous materials, could be categorized as mixed kinds i/ii isotherms and h3 type hysteresis based on the adsorption-desorption data forms at 77.35 k [25,44]. the microporous adsorption contribution in fex zeolite was lower than in nax zeolite due to fe exchange on zeolite, so the surface of the zeolite became more porous and rougher. demonstrating this the fact that the slope of the region in the middle of the desorption isotherm curves of the nax zeolites increased after fe (ii) exchanges were placed. fig. 1 (b) showed nitrogen adsorption/desorption on fex at 77.35 k; the hysteresis loop for nitrogen adsorption on the sample closed at a relative pressure of 4.0–4.5 [25], indicating small mesopores, as shown in the figure. the hysteresis stayed open longer, but the nitrogen meniscus failed due to tensile strength failure; hysteresis (type h3) demonstrates capillary condensation in mesopores by the iupac [25]. the initial steep slope indicates where monolayer formation was most likely to occur. the first few multilayers can be seen in the middle of the isotherm's low slope zone. s. k. kamal and a. s. abbas / iraqi journal of chemical and petroleum engineering 23,4 (2022) 3341 36 the langmuir, freundlich, and bet isotherm models were employed to explain the experimental results of n2 adsorption on the surface of nax and fex zeolites. fig. 2 to fig. 4 illustrate the nax zeolite and fex isotherm models. langmuir isotherm model shown as eq. 1 in fig. 2 was displayed for nax and fex zeolites. the isotherm model was a better fit for the n2 adsorption data for the nax zeolite (fig. 2, a) with a correlation value (r2) of 0.9999, while the correlation coefficient (r2) for the fex zeolite was 0.9978 (fig. 2, b). both the nax and fex adsorption data were well represented by the freundlich isotherm model (eq. 2), as shown in fig. 3, with correlation coefficients r2 equal to 0.9961 for nax zeolite and 0.9929 for fex. the bet isotherm model (eq. 3) correctly fitted the n2 adsorption data for both mesoporous, with correlation coefficient (r2) equal to 0.9914 and 0.9996, for nax zeolite and fex, respectively. table 1 shows the regression coefficients and fitted constants for nax zeolite and fex isotherm models. according to the bet isotherm model, nax zeolite had an adsorption capacity of 188.39 cm3/g, while fex had an adsorption capacity of 68.05cm3/g. the surface area of nax zeolite and fex was calculated using the bet model (eq. 4), and found after the ion-exchange process, the surface area decreased from 569.14 m2/g and 213.31 m2/g, respectively. fig. 5 the pore size distribution for the examined mesoporous adsorbents was calculated using the bjh model and n2 adsorption data at 77.35 k nax and fex zeolites. nax had a wider pore size distribution (fig. 5, a) than fex (fig. 5, b). the peaks of the two materials' pore size distribution (mode pore size diameter) were 2.45 nm for nax and 5.19 nm for fex. nax had a total pore volume of 0.349 cm3/g, while fex had a total pore volume of 5.190 cm3/g. the ion-exchange process appears to impact characteristics such as surface area and pore volume significantly. (a) (b) fig. 1. n2 adsorption-desorption isotherm (a) nax zeolite (b) fex. (a) (b) fig. 2. n2 adsorption isotherm by langmuir model (a) nax zeolite (b) fex. s. k. kamal and a. s. abbas / iraqi journal of chemical and petroleum engineering 23,4 (2022) 3341 37 (a) (b) fig. 3. n2 adsorption isotherm via freundlich model (a) nax zeolite (b) fex table 1. the parameters and r2 for the isotherm models isotherm model nax zeolite fex langmuir qm (cm 3/g) 188.39 68.05 kl (1/mm hg) 47.4369 2.9932 r2 0.9999 0.9978 freundlich kf 167.5328 25.9059 n 70.9219 5.5862 r2 0.9961 0.9929 bet qm(cm 3/g) 130.6585 48.9753 c -45.97 762.33 r2 0.9914 0.9996 (a) (b) fig. 4. n2 adsorption isotherm via bet (a) nax zeolite (b) fex. textural parameters were compared and summarized in table 2 for zeolite and fex, as well as various properties for mesoporous with the same porous structure described in earlier studies [30,44-46]. the surface area of the current nax was 569.14 m2/g, which was comparable to nax [30,44-46]. however, the surface area of the present fex was 213.31 m2/g, which was similar to the surface area of the fe-zeolite obtained [44] and lower than the stated surface area of fe2o3-13x [46]. the present nax has a vp value of 0.34901 cm 3/g, greater than the previous work for the nax [30] and zeolite y [44]. the current fex vp (0.2768 cm3/g) was in the same range as the obtained fe exchange [44-46]. s. k. kamal and a. s. abbas / iraqi journal of chemical and petroleum engineering 23,4 (2022) 3341 38 (a) (b) fig. 5. bjh particle size distribution for (a) nax zeolite (b) fex table 2. the textural characterization for various zeolite found from n2 adsorption at 77.35 k zeolite s bet, m 2/g vp, cm 3/g dbjh, nm reference nax 569.141 0.3490 2.4529 current study nax 556 0.3270 --[30] nax 573 0.36 2.3 [46] zeolite y 432 0.24 --[44] fex 213.31 0.2768 5.1902 current study fe2o3-13x 541 0.21 2.6 [46] fe-zeolite 259 0.10 --[44] 4conclusions mixed kinds of i/ii isotherms and h3 type hysteresis were noticed in the nitrogen adsorption isotherms on nax and fex zeolites according to iupac. a more precise pore size may be obtained from the evaluation of an adsorption branch since both micropore and mesopore adsorptions contribute to the adsorption process. the bet isotherm model best represented the experimental results for nax and fex zeolites, which had high regression coefficients of r2 = 0.9914 and 0.9996, respectively. the bet isotherm model estimated the adsorption capacities of nax and fex to be 188.39 cm3/g and 68.05 cm3/g, respectively; the sbet values for nax and fex were 569.14 m2/g and 213.31 m2/g. according to the bjh model, nax pore size distribution was wider than fex pore size distribution. the dbjh for nax was 2.4529 nm and 5.1902 nm for fex, and vp was 0.3490 cm 3/g for nax and for fex 0.2768 cm3/g. the comparative research findings between the characteristics and those published suggested that the surface area of nax and vp had converged. the comparison findings between the sbet and vp of fex equaled and were less than those of fex. nomenclature nomenclature meaning unit am adsorption crosssectional area of the adsorbing species nm2 cbet bet constant c constant which depends on a curvature equal to 2, in cylindrical shapes dbjh pore diameter by bjh nm fex fe exchange on nax zeolite kf freundlich isotherm constant kl langmuir isotherm constant 1/mm hg n avogadro's number (6.02*1023) mol-1 n adsorption intensity p pressure mm hg p/po relative pressure q nitrogen adsorbed volume at standard pressure and temperature (stp) cm3/g qm the maximum amount of nitrogen that can be adsorbate to form a monolayer on a solid surface completely cm3/g r the liquid's radius of curvature cm r the gas constant l.mm hg/mol k s. k. kamal and a. s. abbas / iraqi journal of chemical and petroleum engineering 23,4 (2022) 3341 39 sbet bet surface area m 2/g st total surface area m 2/g stp standard temperature (273 k) and pressure (1 atm) t temperature k t adsorption layer thickness still present on the pores' walls v nitrogen absorbed molar volume (22.414) l/mole v the condensed adsorptive molar volume vp pore volume cm 3/g γ liquid surface tension dyne/cm θ the contact angle between the solid and condensed phase references [1] a. mhemeed, "a general overview on the adsorption," indian j. nat. sci., vol. 9, no. 51, pp. 16127–16131, 2018. [2] p. panneerselvam, n. thinakaran, k. v. thiruvenkataravi, m. palanichamy, and s. sivanesan, "phosphoric acid modified-y zeolites: a novel, efficient and versatile ion exchanger," j. hazard. mater., vol. 159, no. 2–3, pp. 427–434, nov. 2008, doi: 10.1016/j.jhazmat.2008.02.033. [3] d. w. astuti, mudasir, and n. h. aprilita, "preparation and characterization adsorbent based on zeolite from klaten, central java, indonesia," j. phys. conf. ser., vol. 1156, no. 1, p. 012002, jan. 2019, doi: 10.1088/1742-6596/1156/1/012002. [4] i. w. nah, k.-y. hwang, and y.-g. shul, "a simple synthesis of magnetically modified zeolite," powder technol., vol. 177, no. 2, pp. 99–101, aug. 2007. [5] a. a. mohammed and m. k. baki, "separation benzene and toluene from btx using zeolite 13x," iraqi j. chem. pet. eng., vol. 9, no. 3, pp. 17–22, 2008. [6] a. h. a. k. mohammed. and m. m. abdul-raheem, "adsorption of btx aromatic from reformate by 13x molecular sieve," iraqi j. chem. pet. eng., vol. 9, no. 4, pp. 13–20, 2008. [7] h. mousavi, j. towfighi darian, and b. mokhtarani, "enhanced nitrogen adsorption capacity on ca2+ ionexchanged hierarchical x zeolite," sep. purif. technol., vol. 264, no. september 2020, p. 118442, jun. 2021, doi: 10.1016/j.seppur.2021.118442. [8] z. a. hammood, t. f. chyad, and r. al-saedi, "adsorption performance of dyes over zeolite for textile wastewater treatment," ecol. chem. eng. s, vol. 28, no. 3, pp. 329–337, sep. 2021. [9] s. k. a. barno, h. j. mohamed, s. m. saeed, m. j. al-ani, and a. s. abbas, "prepared 13x zeolite as a promising adsorbent for the removal of brilliant blue dye from wastewater," iraqi j. chem. pet. eng., vol. 22, no. 2, pp. 1–6, jun. 2021. [10] t. p. belova, "adsorption of heavy metal ions (cu2+, ni2+, co2+ and fe2+) from aqueous solutions by natural zeolite," heliyon, vol. 5, no. 9, p. e02320, sep. 2019, doi: 10.1016/j.heliyon.2019.e02320. [11] l. f. de magalhães, g. r. da silva, and a. e. c. peres, "zeolite application in wastewater treatment," adsorpt. sci. technol., vol. 2022, pp. 1– 26, feb. 2022, doi: 10.1155/2022/4544104. [12] e. erdem, n. karapinar, and r. donat, "the removal of heavy metal cations by natural zeolites," j. colloid interface sci., vol. 280, no. 2, pp. 309–314, dec. 2004, doi: 10.1016/j.jcis.2004.08.028. [13] h. l. tran, m. s. kuo, w. d. yang, and y. c. huang, "study on modification of nax zeolites: the cobalt (ii)-exchange kinetics and surface property changes under thermal treatment," j. chem., vol. 2016, no. ii, 2016, doi: 10.1155/2016/1789680. [14] e. asedegbega-nieto, e. díaz, a. vega, and s. ordóñez, “transition metal-exchanged lta zeolites as novel catalysts for methane combustion,” catal. today, vol. 157, no. 1–4, pp. 425–431, nov. 2010, doi: 10.1016/j.cattod.2010.05.032. [15] e. v. kuznetsova, e. n. savinov, l. a. vostrikova, and v. n. parmon, "heterogeneous catalysis in the fenton-type system fezsm-5/h2o2," appl. catal. b environ., vol. 51, no. 3, pp. 165–170, aug. 2004, doi: 10.1016/j.apcatb.2004.03.002. [16] b. a. alshahidy and a. s. abbas, "comparative study on the catalytic performance of a 13x zeolite and its dealuminated derivative for biodiesel production," bull. chem. react. eng. catal., vol. 16, no. 4, pp. 763–772, dec. 2021, doi: 10.9767/bcrec.16.4.11436.763-772. [17] b. a. alshahidy and a. s. abbas, "preparation and modification of 13x zeolite as a heterogeneous catalyst for esterification of oleic acid," aip conf. proc., vol. 2213, no. march, 2020. [18] a. gęsikiewicz-puchalska et al., "changes in porous parameters of the ion exchanged x zeolite and their effect on co2 adsorption," molecules, vol. 26, no. 24, 2021, doi: 10.3390/molecules26247520. [19] y. zeng, "fundamental study of adsorption and desorption process in porous materials with functional groups," p. 122, 2016. [20] m. alaqarbeh, "adsorption phenomena : definition , mechanisms , and adsorption types : rhazes : green and applied chemistry adsorption phenomena : definition , mechanisms , and adsorption types : short review," no. september, 2021, doi: 10.48419/imist.prsm/rhazesv13.28283. [21] r. t. yang, "adsorbents: fundamentals and applications," wiley-interscience, 2003. [22] s. m. gawande, n. s. belwalkar, and a. a. mane, "adsorption and its isotherm – theory," int. j. eng. res., vol. 6, no. 6, p. 312, 2017, doi: 10.5958/23196890.2017.00026.5. [23] g. f. bennett, partition and adsorption of organic contaminants in environmental systems, vol. 98, no. 1–3. 2003. https://www.researchgate.net/profile/amal-mhemeed/publication/329964251_a_general_overview_on_the_adsorption/links/5c2609d0a6fdccfc706d4d01/a-general-overview-on-the-adsorption.pdf https://www.researchgate.net/profile/amal-mhemeed/publication/329964251_a_general_overview_on_the_adsorption/links/5c2609d0a6fdccfc706d4d01/a-general-overview-on-the-adsorption.pdf https://www.researchgate.net/profile/amal-mhemeed/publication/329964251_a_general_overview_on_the_adsorption/links/5c2609d0a6fdccfc706d4d01/a-general-overview-on-the-adsorption.pdf https://www.sciencedirect.com/science/article/abs/pii/s0304389408002689 https://www.sciencedirect.com/science/article/abs/pii/s0304389408002689 https://www.sciencedirect.com/science/article/abs/pii/s0304389408002689 https://www.sciencedirect.com/science/article/abs/pii/s0304389408002689 https://www.sciencedirect.com/science/article/abs/pii/s0304389408002689 https://www.sciencedirect.com/science/article/abs/pii/s0304389408002689 https://iopscience.iop.org/article/10.1088/1742-6596/1156/1/012002/meta https://iopscience.iop.org/article/10.1088/1742-6596/1156/1/012002/meta https://iopscience.iop.org/article/10.1088/1742-6596/1156/1/012002/meta https://iopscience.iop.org/article/10.1088/1742-6596/1156/1/012002/meta https://iopscience.iop.org/article/10.1088/1742-6596/1156/1/012002/meta https://www.sciencedirect.com/science/article/abs/pii/s0032591007001118 https://www.sciencedirect.com/science/article/abs/pii/s0032591007001118 https://www.sciencedirect.com/science/article/abs/pii/s0032591007001118 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/442 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/442 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/442 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/442 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/450 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/450 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/450 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/450 https://www.sciencedirect.com/science/article/abs/pii/s1383586621001441 https://www.sciencedirect.com/science/article/abs/pii/s1383586621001441 https://www.sciencedirect.com/science/article/abs/pii/s1383586621001441 https://www.sciencedirect.com/science/article/abs/pii/s1383586621001441 https://www.sciencedirect.com/science/article/abs/pii/s1383586621001441 https://www.researchgate.net/profile/tasnim-chyad/publication/355181574_adsorption_performance_of_dyes_over_zeolite_for_textile_wastewater_treatment/links/616ad1b8951b3574c64c5936/adsorption-performance-of-dyes-over-zeolite-for-textile-wastewater-treatment.pdf https://www.researchgate.net/profile/tasnim-chyad/publication/355181574_adsorption_performance_of_dyes_over_zeolite_for_textile_wastewater_treatment/links/616ad1b8951b3574c64c5936/adsorption-performance-of-dyes-over-zeolite-for-textile-wastewater-treatment.pdf https://www.researchgate.net/profile/tasnim-chyad/publication/355181574_adsorption_performance_of_dyes_over_zeolite_for_textile_wastewater_treatment/links/616ad1b8951b3574c64c5936/adsorption-performance-of-dyes-over-zeolite-for-textile-wastewater-treatment.pdf https://www.researchgate.net/profile/tasnim-chyad/publication/355181574_adsorption_performance_of_dyes_over_zeolite_for_textile_wastewater_treatment/links/616ad1b8951b3574c64c5936/adsorption-performance-of-dyes-over-zeolite-for-textile-wastewater-treatment.pdf https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/836 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/836 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/836 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/836 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/836 https://www.sciencedirect.com/science/article/pii/s2405844019359808 https://www.sciencedirect.com/science/article/pii/s2405844019359808 https://www.sciencedirect.com/science/article/pii/s2405844019359808 https://www.sciencedirect.com/science/article/pii/s2405844019359808 https://www.hindawi.com/journals/ast/2022/4544104/ https://www.hindawi.com/journals/ast/2022/4544104/ https://www.hindawi.com/journals/ast/2022/4544104/ https://www.hindawi.com/journals/ast/2022/4544104/ https://www.sciencedirect.com/science/article/abs/pii/s0021979704007416 https://www.sciencedirect.com/science/article/abs/pii/s0021979704007416 https://www.sciencedirect.com/science/article/abs/pii/s0021979704007416 https://www.sciencedirect.com/science/article/abs/pii/s0021979704007416 https://www.hindawi.com/journals/jchem/2016/1789680/ https://www.hindawi.com/journals/jchem/2016/1789680/ https://www.hindawi.com/journals/jchem/2016/1789680/ https://www.hindawi.com/journals/jchem/2016/1789680/ https://www.hindawi.com/journals/jchem/2016/1789680/ https://www.sciencedirect.com/science/article/abs/pii/s0920586110003688 https://www.sciencedirect.com/science/article/abs/pii/s0920586110003688 https://www.sciencedirect.com/science/article/abs/pii/s0920586110003688 https://www.sciencedirect.com/science/article/abs/pii/s0920586110003688 https://www.sciencedirect.com/science/article/abs/pii/s0920586110003688 https://www.sciencedirect.com/science/article/abs/pii/s0926337304001183 https://www.sciencedirect.com/science/article/abs/pii/s0926337304001183 https://www.sciencedirect.com/science/article/abs/pii/s0926337304001183 https://www.sciencedirect.com/science/article/abs/pii/s0926337304001183 https://www.sciencedirect.com/science/article/abs/pii/s0926337304001183 https://ejournal2.undip.ac.id/index.php/bcrec/article/view/11436 https://ejournal2.undip.ac.id/index.php/bcrec/article/view/11436 https://ejournal2.undip.ac.id/index.php/bcrec/article/view/11436 https://ejournal2.undip.ac.id/index.php/bcrec/article/view/11436 https://ejournal2.undip.ac.id/index.php/bcrec/article/view/11436 https://ejournal2.undip.ac.id/index.php/bcrec/article/view/11436 https://aip.scitation.org/doi/abs/10.1063/5.0000171 https://aip.scitation.org/doi/abs/10.1063/5.0000171 https://aip.scitation.org/doi/abs/10.1063/5.0000171 https://aip.scitation.org/doi/abs/10.1063/5.0000171 https://www.mdpi.com/1420-3049/26/24/7520 https://www.mdpi.com/1420-3049/26/24/7520 https://www.mdpi.com/1420-3049/26/24/7520 https://www.mdpi.com/1420-3049/26/24/7520 https://core.ac.uk/download/pdf/83972167.pdf https://core.ac.uk/download/pdf/83972167.pdf https://core.ac.uk/download/pdf/83972167.pdf https://revues.imist.ma/index.php/rhazes/article/view/28283 https://revues.imist.ma/index.php/rhazes/article/view/28283 https://revues.imist.ma/index.php/rhazes/article/view/28283 https://revues.imist.ma/index.php/rhazes/article/view/28283 https://revues.imist.ma/index.php/rhazes/article/view/28283 https://revues.imist.ma/index.php/rhazes/article/view/28283 https://revues.imist.ma/index.php/rhazes/article/view/28283 https://books.google.iq/books?hl=en&lr=&id=7m3ukqqiaiec&oi=fnd&pg=pr5&dq=%5b21%5d%09r.+t.+yang,+%22adsorbents:+fundamentals+and+applications,%22+wiley-interscience,+2003.&ots=5xgj9kh1ar&sig=v2axee2vlx9oxxgix1d--ep3b6o&redir_esc=y#v=onepage&q=%5b21%5d%09r.%20t.%20yang%2c%20%22adsorbents%3a%20fundamentals%20and%20applications%2c%22%20wiley-interscience%2c%202003.&f=false https://books.google.iq/books?hl=en&lr=&id=7m3ukqqiaiec&oi=fnd&pg=pr5&dq=%5b21%5d%09r.+t.+yang,+%22adsorbents:+fundamentals+and+applications,%22+wiley-interscience,+2003.&ots=5xgj9kh1ar&sig=v2axee2vlx9oxxgix1d--ep3b6o&redir_esc=y#v=onepage&q=%5b21%5d%09r.%20t.%20yang%2c%20%22adsorbents%3a%20fundamentals%20and%20applications%2c%22%20wiley-interscience%2c%202003.&f=false https://d1wqtxts1xzle7.cloudfront.net/53381819/70_312-316_ijer_2017_612_sagar_gawande-libre.pdf?1496556804=&response-content-disposition=inline%3b+filename%3dadsorption_and_its_isotherm_theory.pdf&expires=1671052067&signature=e5ht7kdkilafinrb1tdeaeslq-gduo4o3thba3vpzuhwszk8vs-bluovwmhopvd7ak2iee~ybwl7ugdf-nwmkrn7umsmn3dtede5tpxdghpnqziul7vsg4p9d5brmjyhpazfqjhkiwgaym~f3kxvpx1glzxqvdcg5rnv9o5uereddchmcpjbfu9edfeuo9vmdgduotgqfqolk-rcy9xcc0kd9vff7jyj2mttwrtmo-aj1slp4bo1kd0knfbhqqhaznriiuodmqkl9dnx~cx4xp2r4u7scqu5f7djjtzwfmafe90jwtdia96udwrr6p5izvt7wfud0i0qr2duze5a7a__&key-pair-id=apkajlohf5ggslrbv4za 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https://d1wqtxts1xzle7.cloudfront.net/53381819/70_312-316_ijer_2017_612_sagar_gawande-libre.pdf?1496556804=&response-content-disposition=inline%3b+filename%3dadsorption_and_its_isotherm_theory.pdf&expires=1671052067&signature=e5ht7kdkilafinrb1tdeaeslq-gduo4o3thba3vpzuhwszk8vs-bluovwmhopvd7ak2iee~ybwl7ugdf-nwmkrn7umsmn3dtede5tpxdghpnqziul7vsg4p9d5brmjyhpazfqjhkiwgaym~f3kxvpx1glzxqvdcg5rnv9o5uereddchmcpjbfu9edfeuo9vmdgduotgqfqolk-rcy9xcc0kd9vff7jyj2mttwrtmo-aj1slp4bo1kd0knfbhqqhaznriiuodmqkl9dnx~cx4xp2r4u7scqu5f7djjtzwfmafe90jwtdia96udwrr6p5izvt7wfud0i0qr2duze5a7a__&key-pair-id=apkajlohf5ggslrbv4za https://books.google.iq/books?hl=en&lr=&id=mtkaj-naiqsc&oi=fnd&pg=pr5&dq=%5b23%5d%09g.+f.+bennett,+partition+and+adsorption+of+organic+contaminants+in+environmental+systems,+vol.+98,+no.+1%e2%80%933.+2003.&ots=a3hkgkz_cg&sig=i3v2hb3cye0-5qql-mtl8jgff34&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=mtkaj-naiqsc&oi=fnd&pg=pr5&dq=%5b23%5d%09g.+f.+bennett,+partition+and+adsorption+of+organic+contaminants+in+environmental+systems,+vol.+98,+no.+1%e2%80%933.+2003.&ots=a3hkgkz_cg&sig=i3v2hb3cye0-5qql-mtl8jgff34&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=mtkaj-naiqsc&oi=fnd&pg=pr5&dq=%5b23%5d%09g.+f.+bennett,+partition+and+adsorption+of+organic+contaminants+in+environmental+systems,+vol.+98,+no.+1%e2%80%933.+2003.&ots=a3hkgkz_cg&sig=i3v2hb3cye0-5qql-mtl8jgff34&redir_esc=y#v=onepage&q&f=false s. k. kamal and a. s. abbas / iraqi journal of chemical and petroleum engineering 23,4 (2022) 3341 40 [24] m. a. al-ghouti and d. a. da'ana, "guidelines for the use and interpretation of adsorption isotherm models: a review," j. hazard. mater., vol. 393, no. february, p. 122383, jul. 2020, doi: 10.1016/j.jhazmat.2020.122383. [25] m. thommes et al., "physisorption of gases, with special reference to the evaluation of surface area and pore size distribution (iupac technical report)," pure appl. chem., vol. 87, no. 9–10, pp. 1051–1069, 2015, doi: 10.1515/pac-2014-1117. [26] k. sing, "the use of nitrogen adsorption for the characterisation of porous materials," colloids surfaces a physicochem. eng. asp., vol. 187–188, pp. 3–9, aug. 2001, doi: 10.1016/s09277757(01)00612-4. [27] b. kurji, a. abbas, and i. marshes research center, "comparative study of textural properties for various silica by nitrogen adsorption-desorption technique," egypt. j. chem., 2022, doi: https://dx.doi.org/10.21608/ejchem.2022.125169.556 8. [28] a. i. moral-rodríguez et al., "tailoring the textural properties of an activated carbon for enhancing its adsorption capacity towards diclofenac from aqueous solution.," environ. sci. pollut. res. int., vol. 26, no. 6, pp. 6141–6152, feb. 2019, doi: 10.1007/s11356018-3991-x. [29] m. n. alaya, a m. youssef, m. karman, and h. e. a. el-aal, "textural properties of activated carbons from wild cherry stones as determined by nitrogen and carbon dioxide adsorption," vol. 7, no. 1, pp. 9– 18, 2006. [30] h. hammoudi, s. bendenia, k. marouf-khelifa, r. marouf, j. schott, and a. khelifa, "effect of the binary and ternary exchanges on crystallinity and textural properties of x zeolites," microporous mesoporous mater., vol. 113, no. 1–3, pp. 343–351, aug. 2008, doi: 10.1016/j.micromeso.2007.11.032. [31] i. langmuir, "the constitution and fundamental properties of solids and liquids. part ii.-liquids," j. franklin inst., vol. 184, no. 5, p. 721, 1917, doi: 10.1016/s0016-0032(17)90088-2. [32] j. h. de boer, "adsorption phenomena," in physical chemistry of solid-gas interfaces, london, uk: iste, 1956, pp. 1–27. [33] h. zhang, a. goeppert, s. kar, and g. k. s. prakash, "structural parameters to consider in selecting silica supports for polyethylenimine based co2 solid adsorbents. importance of pore size," j. co2 util., vol. 26, pp. 246–253, jul. 2018, doi: 10.1016/j.jcou.2018.05.004. [34] b. h. hameed, d. k. mahmoud, and a. l. ahmad, "equilibrium modeling and kinetic studies on the adsorption of basic dye by a low-cost adsorbent: coconut (cocos nucifera) bunch waste," j. hazard. mater., vol. 158, no. 1, pp. 65–72, oct. 2008, doi: 10.1016/j.jhazmat.2008.01.034. [35] k. y. foo and b. h. hameed, "insights into the modeling of adsorption isotherm systems," chem. eng. j., vol. 156, no. 1, pp. 2–10, jan. 2010. [36] p. m. v. raja and a. r. barron, "bet surface area analysis of nanoparticles," phys. methods chem. nano sci., vol. i, pp. 1–7, 2019. [37] e. sugawara and h. nikaido, "properties of adeabc and adeijk efflux systems of acinetobacter baumannii compared with those of the acrab-tolc system of escherichia coli.," antimicrob. agents chemother., vol. 58, no. 12, pp. 7250–7, dec. 2014, doi: 10.1128/aac.03728-14. [38] m. thommes, "physical adsorption characterization of nanoporous materials," chemie-ingenieurtechnik, vol. 82, no. 7, pp. 1059–1073, 2010, doi: 10.1002/cite.201000064. [39] a. marcilla, a. gomez-siurana, m. m. josé, and f. j. valdés, "comments on the methods of characterization of textural properties of solids from gas adsorption data," adsorpt. sci. technol., vol. 27, no. 1, pp. 69–84, feb. 2009, doi: 10.1260/026361709788921579. [40] b. x. medina-rodriguez and v. alvarado, "use of gas adsorption and inversion methods for shale pore structure characterization," energies, vol. 14, no. 10, p. 2880, may 2021, doi: 10.3390/en14102880. [41] e. p. barrett, l. g. joyner, and p. p. halenda, "the determination of pore volume and area distributions in porous substances. i. computations from nitrogen isotherms," j. am. chem. soc., vol. 73, no. 1, pp. 373–380, 1951, doi: 10.1021/ja01145a126. [42] d. dollimore and g. r. heal, "pore-size distribution in typical adsorbent systems," j. colloid interface sci., vol. 33, no. 4, pp. 508–519, 1970, doi: 10.1016/0021-9797(70)90002-0. [43] s. geraedts, "pore size distribution and surface group analysis a study of two electrical grade carbon blacks," eindhoven univ. technol., 2002. [44] m. l. rache, a. r. garcía, h. r. zea, a. m. t. silva, l. m. madeira, and j. h. ramírez, "azo-dye orange ii degradation by the heterogeneous fenton-like process using a zeolite y-fe catalyst—kinetics with a model based on the fermi's equation," appl. catal. b environ., vol. 146, pp. 192–200, mar. 2014, doi: 10.1016/j.apcatb.2013.04.028. [45] s. k. kamal, a. s. abbas “langmuir-hinshelwoodhougen-watson heterogeneous kinetics model for the description of fe ( ii ) ion exchange on na-x zeolite,” eng. technol. appl. sci. res., vol. 12, no. 5, pp. 9265–9269, 2022. [46] a. a. abdulrazak and s. rohani, "sodium dodecyl sulfate-modified fe 2 o 3 /molecular sieves for removal of rhodamine b dyes," adv. mater. sci. eng., vol. 2018, pp. 1–10, 2018, doi: 10.1155/2018/3849867. https://www.sciencedirect.com/science/article/abs/pii/s030438942030371x https://www.sciencedirect.com/science/article/abs/pii/s030438942030371x https://www.sciencedirect.com/science/article/abs/pii/s030438942030371x https://www.sciencedirect.com/science/article/abs/pii/s030438942030371x https://www.sciencedirect.com/science/article/abs/pii/s030438942030371x https://www.degruyter.com/document/doi/10.1515/pac-2014-1117/html?lang=de https://www.degruyter.com/document/doi/10.1515/pac-2014-1117/html?lang=de https://www.degruyter.com/document/doi/10.1515/pac-2014-1117/html?lang=de https://www.degruyter.com/document/doi/10.1515/pac-2014-1117/html?lang=de https://www.degruyter.com/document/doi/10.1515/pac-2014-1117/html?lang=de https://www.sciencedirect.com/science/article/abs/pii/s0927775701006124 https://www.sciencedirect.com/science/article/abs/pii/s0927775701006124 https://www.sciencedirect.com/science/article/abs/pii/s0927775701006124 https://www.sciencedirect.com/science/article/abs/pii/s0927775701006124 https://www.sciencedirect.com/science/article/abs/pii/s0927775701006124 https://link.springer.com/article/10.1007/s11356-018-3991-x https://link.springer.com/article/10.1007/s11356-018-3991-x https://link.springer.com/article/10.1007/s11356-018-3991-x https://link.springer.com/article/10.1007/s11356-018-3991-x https://link.springer.com/article/10.1007/s11356-018-3991-x https://link.springer.com/article/10.1007/s11356-018-3991-x https://koreascience.kr/article/jako200622463506009.page https://koreascience.kr/article/jako200622463506009.page https://koreascience.kr/article/jako200622463506009.page https://koreascience.kr/article/jako200622463506009.page https://koreascience.kr/article/jako200622463506009.page https://www.sciencedirect.com/science/article/abs/pii/s1387181107006993 https://www.sciencedirect.com/science/article/abs/pii/s1387181107006993 https://www.sciencedirect.com/science/article/abs/pii/s1387181107006993 https://www.sciencedirect.com/science/article/abs/pii/s1387181107006993 https://www.sciencedirect.com/science/article/abs/pii/s1387181107006993 https://www.sciencedirect.com/science/article/abs/pii/s1387181107006993 https://pubs.acs.org/doi/pdf/10.1021/ja02254a006 https://pubs.acs.org/doi/pdf/10.1021/ja02254a006 https://pubs.acs.org/doi/pdf/10.1021/ja02254a006 https://pubs.acs.org/doi/pdf/10.1021/ja02254a006 https://www.sciencedirect.com/science/article/abs/pii/s2212982018302385 https://www.sciencedirect.com/science/article/abs/pii/s2212982018302385 https://www.sciencedirect.com/science/article/abs/pii/s2212982018302385 https://www.sciencedirect.com/science/article/abs/pii/s2212982018302385 https://www.sciencedirect.com/science/article/abs/pii/s2212982018302385 https://www.sciencedirect.com/science/article/abs/pii/s2212982018302385 https://www.sciencedirect.com/science/article/abs/pii/s0304389408000988 https://www.sciencedirect.com/science/article/abs/pii/s0304389408000988 https://www.sciencedirect.com/science/article/abs/pii/s0304389408000988 https://www.sciencedirect.com/science/article/abs/pii/s0304389408000988 https://www.sciencedirect.com/science/article/abs/pii/s0304389408000988 https://www.sciencedirect.com/science/article/abs/pii/s0304389408000988 https://www.sciencedirect.com/science/article/abs/pii/s1385894709006147 https://www.sciencedirect.com/science/article/abs/pii/s1385894709006147 https://www.sciencedirect.com/science/article/abs/pii/s1385894709006147 https://journals.asm.org/doi/full/10.1128/aac.03728-14 https://journals.asm.org/doi/full/10.1128/aac.03728-14 https://journals.asm.org/doi/full/10.1128/aac.03728-14 https://journals.asm.org/doi/full/10.1128/aac.03728-14 https://journals.asm.org/doi/full/10.1128/aac.03728-14 https://journals.asm.org/doi/full/10.1128/aac.03728-14 https://onlinelibrary.wiley.com/doi/abs/10.1002/cite.201000064 https://onlinelibrary.wiley.com/doi/abs/10.1002/cite.201000064 https://onlinelibrary.wiley.com/doi/abs/10.1002/cite.201000064 https://onlinelibrary.wiley.com/doi/abs/10.1002/cite.201000064 https://journals.sagepub.com/doi/abs/10.1260/026361709788921579 https://journals.sagepub.com/doi/abs/10.1260/026361709788921579 https://journals.sagepub.com/doi/abs/10.1260/026361709788921579 https://journals.sagepub.com/doi/abs/10.1260/026361709788921579 https://journals.sagepub.com/doi/abs/10.1260/026361709788921579 https://journals.sagepub.com/doi/abs/10.1260/026361709788921579 https://www.mdpi.com/1996-1073/14/10/2880 https://www.mdpi.com/1996-1073/14/10/2880 https://www.mdpi.com/1996-1073/14/10/2880 https://www.mdpi.com/1996-1073/14/10/2880 https://www.mdpi.com/1996-1073/14/10/2880 https://pubs.acs.org/doi/pdf/10.1021/ja01145a126 https://pubs.acs.org/doi/pdf/10.1021/ja01145a126 https://pubs.acs.org/doi/pdf/10.1021/ja01145a126 https://pubs.acs.org/doi/pdf/10.1021/ja01145a126 https://pubs.acs.org/doi/pdf/10.1021/ja01145a126 https://pubs.acs.org/doi/pdf/10.1021/ja01145a126 https://www.sciencedirect.com/science/article/abs/pii/0021979770900020 https://www.sciencedirect.com/science/article/abs/pii/0021979770900020 https://www.sciencedirect.com/science/article/abs/pii/0021979770900020 https://www.sciencedirect.com/science/article/abs/pii/0021979770900020 https://pure.tue.nl/ws/files/47047061/597384-1.pdf https://pure.tue.nl/ws/files/47047061/597384-1.pdf https://pure.tue.nl/ws/files/47047061/597384-1.pdf https://www.sciencedirect.com/science/article/abs/pii/s0926337313002373 https://www.sciencedirect.com/science/article/abs/pii/s0926337313002373 https://www.sciencedirect.com/science/article/abs/pii/s0926337313002373 https://www.sciencedirect.com/science/article/abs/pii/s0926337313002373 https://www.sciencedirect.com/science/article/abs/pii/s0926337313002373 https://www.sciencedirect.com/science/article/abs/pii/s0926337313002373 https://www.sciencedirect.com/science/article/abs/pii/s0926337313002373 https://etasr.com/index.php/etasr/article/view/5161 https://etasr.com/index.php/etasr/article/view/5161 https://etasr.com/index.php/etasr/article/view/5161 https://etasr.com/index.php/etasr/article/view/5161 https://etasr.com/index.php/etasr/article/view/5161 https://www.hindawi.com/journals/amse/2018/3849867/ https://www.hindawi.com/journals/amse/2018/3849867/ https://www.hindawi.com/journals/amse/2018/3849867/ https://www.hindawi.com/journals/amse/2018/3849867/ https://www.hindawi.com/journals/amse/2018/3849867/ s. k. kamal and a. s. abbas / iraqi journal of chemical and petroleum engineering 23,4 (2022) 3341 41 متزاز ا-اصبواسطة تقنية امتص fe-x و nax توصيف الخصائص التركيبية لزيوليت النيتروجين سناريا كامل كمال و عمار صالح عباس جامعة بغداد /كلية الهندسة /قسم الهندسة الكيمياوية الخالصة ا هدف هذللخصائص التركيبية للزيوليت تأثير كبير على فعالية الزيوليت في العمليات الصناعية المختلفة. ي االمتصاص -باستخدام تقنية امتصاص النيتروجين fexو naxالبحث إلى دراسة الخصائص النصية لزيوليت متصاصالتطبيقية ، أظهر متساوي االعند درجة حرارة منخفضة ثابتة. وفًقا لالتحاد الدولي للكيمياء البحتة و ي . كانت متساو h3متساوي الحرارة ونوع i / iiواالمتصاص أن المواد المدروسة كانت مختلطة من النوعين أفضل نموذج لوصف امتزاز وامتصاص النيتروجين بشكل أفضل من brunauer-emmett-tellerالحرارة سعة االمتزاز التي تم الحصول عليها وقيم مساحة سطح . كانتfreundlichو langmuirمتساوي الحرارة brunauer-emmett-teller لـnax أكبر من تلك الخاصة بـfex وفًقا لمعادلة كلفن، تم استخدام نموذج . barrett وjoyner وhalenda رة. حجم المسام للزيوليت المختالتحديد توزيع حجم المسام والقطر ومتوسط ، وكان fexأقل من nax، وكان قطر المسام لـ fexأوسع من زيوليت naxلمسام لـ كان توزيع حجم ا سات . أجريت الدراسة المقارنة مع الدراnaxحجم مسام أكبر من قيمة متوسط fexحجم المسام لـ متوسط السابقة، وأظهرت المقارنة أن الخصائص النصية للزيوليت المعدلة تتفق مع الدراسات األخرى. ط حجم متوس متساوي الحرارة، مساحة السطح، توزيع حجم المسام، قطر المسام،ميزوبوروس، ، التبادل األيوني الكلمات الدالة: المسام. iraqi journal of chemical and petroleum engineering vol.14 no.4 (december 2013) 3543 issn: 1997-4884 kinetic study and simulation of oleic acid esterification over prepared nay zeolite catalyst ammar s. abbas and rowaida n. abbas chemical engineering department – college of engineering – university of baghdad abstract esterification considers the most important reaction in biodiesel production. in this study, oleic acid was used as a suggested feedstock in order to study and simulate production of biodiesel. the batch esterification reaction of oleic acid was carried out at various operating conditions; temperature from 40 to 70 °c, ethanol to oleic acid molar ratio from 3/1 and 6/1 and a reaction time up to 180 min. the catalyst used was prepared nay zeolite, which is added to the reaction mixture as 2, 5 and 10 wt.% of oleic acid. the results show that the optimum conditions, gives 0.81 conversion of oleic acid, were 6/1 molar ratio of ethanol/oleic acid, 5 wt.% nay relative to initial oleic acid, 70°c and 60 minutes. the activation energy of the suggested model was 42692 j/mole for forward reaction and 17218 j/mole for backward reaction. key word: oleic acid, esterification, kinetic study, simulation, heterogeneous catalyst, zeolite. introduction one of the most promising sources is biodiesel, an alternative diesel fuel derived from renewable sources with high quality, which allows the substitution of fossil diesel oil without engine modifications [1-3]. biodiesel shows a favorable combustion emission profile, producing much less carbon monoxide, sulfur dioxide and unburned hydrocarbons than petroleum-based diesel fuel [4, 5]. biodiesel can be chemically defined as a fuel composed of monoalkyl esters of long chain fatty acids derived from renewable sources, such as vegetable oils and animal fats [6]. several vegetable oil varieties such as canola, palm, palm kernel, sunflower and coconut oil have been studied as feedstock for biodiesel production [7]. most of the commercial production of biodiesel worldwide uses homogeneous catalysts, which are corrosive and non-reusable and produces waste that needs to be neutralized, hence, increasing the overall costs and leads to an environmental concerns [8]. the choice of the fats or oils to be used in producing biodiesel depends on the process and raw material cost and impurities. low quality oil contains high levels of free fatty acid (ffa) and water. when ffa is present in the feedstock, it reacts with the homogeneous base catalysts and may deactivate the catalyst and form unwanted soap by-products. in iraqi journal of chemical and petroleum engineering university of baghdad college of engineering kinetic study and simulation of oleic acid esterification over prepared nay zeolite catalyst 36 ijcpe vol.14 no.4 (december 2013) -available online at: www.iasj.net addition, the present of water in the reaction mixture also leads to the deactivation of homogeneous catalysts. ma and hanna [9], reported that water should be kept below 0.06 % and ffa should be kept below 0.5 wt. % to get the best conversions. the removal of homogeneous catalysts is technically difficult and large amount of wastewater is produced during the process and needs to be treated via neutralization process [10, 11]. abbas and abbas [12] studied the esterification reaction of oleic acid with ethanol at present of water. the best conditions for the esterification reaction were 6/1 molar ratio of ethanol/oleic acid, 5 wt. % h2so4 relative to oleic acid, 70 °c, 90 min and conversion of oleic 0.92 the activation energy for suggested model were 26625 j/mole for forward reaction and 42189 j/mole for equilibrium constant. in order to reduce the production cost of biodiesel, some researchers conducted research by using a solid catalyst [13]. biodiesel production using solid catalysts has an economic benefit in terms of cheaper production costs because of the reusable nature of the catalyst and the possibility to be used in low quality feedstock [14], and offer the possibility of carrying out both trans-esterification and esterification simultaneously [15]. another advantage of a heterogeneous catalyst is that the catalyst is easily separated from the reactants and products. reduction of the biodiesel production cost can be achieved if a heterogeneous catalyst is used. heterogeneous catalyst offers easier production process, improve product quality and also reduce corrosion and toxicity problems. furthermore, it can be used for low quality feedstock, which contains high ffa [16]. additional benefit with solid based catalyst is the lesser consumption of catalyst. as per studies, for production of 8000 tons of biodiesel, 88 tons of sodium hydroxide may be required [17], while only 5.7 tons of solid supported mgo are sufficient for production of 100,000 tons of biodiesel [18]. the present work, will intend to produce an ethyl ester (biodiesel) from the oleic acid by the esterification process by using nay zeolite as a catalyst. the effects of reaction temperature, catalyst load, and the molar ratio alcohol/oil were considered. also, the kinetics of oleic acid esterification were studied and the results were simulated, using reactop simulation package. experimental work materials 1. oleic acid, obtained from local markets. the specific gravity of the oleic acid is 0.895, bdh chemicals ltd. 2. ethyl alcohol obtained from local markets with specific gravity is 0.7692 (88 to 90 wt. %). 3. the kaolin clay is available locally in al-dewekhala quarry in alenbar region, it was supplied from state company of geological surveying and mining. 4. sodium hydroxide (riedeldehaen ag seelzehannover chem. rian, plozchen, dab7, b.p.1968 m.wt. 40). 5. sodium silicate (na4sio4) was supplied by (bdh limited pool england). 6. phenolphthalein (as indicator), fluka. catalyst preparation kaolin was mixed with 40 wt. % of sodium hydroxide solution using kaolin / naoh = 1/1.5 g/g and fused at ammar s. abbas and rowaida n. abbas -available online at: www.iasj.net ijcpe vol.14 no.4 (december 2013) 37 850˚c for 3 h. 50 g of fused kaolin and 63 g of sodium silicate were placed in 500 ml of deionized water under constant stirring at 50˚c for 1 hour, then the slurry with ph 13.3 was placed in a glass jar and subjected to ageing at 50ᵒc for 24 h. the produced slurry was crystallized at 100 ᵒc for 48 h. the crystalline mass repeatedly washed with water until the ph arriving 11.7, then the crystalline mass was dried at 100 ᵒc for 16 h. all prepared nay zeolite catalyst characterization was done in the state company of geological survey and mining – iraqi ministry of industry and minerals. apparatus the apparatus used in this study for esterification reaction is shown in figure 1. the batch scale system consists of the followings: 1. 3 necks flask (500 ml). 2. heat flat magnetic stirrer (stuart (cb302) /usa. 3. reflux condenser (germany). 4. mercury thermometer from zero to 250 °c. fig. 1, schematic diagram of the reactor esterification of oleic acid the esterification reaction was carried out between acid and free fatty acid (ffa) to produce ester (biodiesel) and water. the system was maintained at atmospheric pressure and experiments were carried out at a constant temperature. the agitation was kept constant at 300 rpm. this process was studied at different percent of ethanol/oil mole ratio of 3/1 and6/1. prepared nay zeolite as a catalyst of 2, 5 and 10 wt. % relative to oleic acid, reaction time up to 150 minutes and at different temperatures 40 to 70 ° c. the esterification reactor was loaded with 15 ml (13.43 g) of oleic acid, and the desired amount of ethanol. the mixture was agitated and preheated to the desired temperature and then nay zeolite was added. at each period of time, 5 ml from the mixture reaction was taken and centrifuged (by griffin and george lough borough/britain centrifuge) for 10 min to improve the separation of the phases and 2 drops of phenolphthalein was added as indicator and titrated with 1 molarity of naoh in order to obtain oleic acid conversion. results and discussion catalyst characterization by x-ray diffraction the comparison between lattice spacing by x-ray diffraction (via xrd-7000 diffractometer) shows that the prepared nay zeolite is approximately comparable with the standard. as shown in figure 2. fig. 2, x-ray diffraction of the prepared nay zeolite kinetic study and simulation of oleic acid esterification over prepared nay zeolite catalyst 38 ijcpe vol.14 no.4 (december 2013) -available online at: www.iasj.net the na2o content of prepared nay zeolite was analyzed and it was 11.8 wt. %. the surface area, measured by bet method, of prepared catalyst was equal to 156.3 m 2 /g. while, the pore volume was equal to 0.255 cm 3 /g. effect of operating temperature and time on the oleic acid conversion figure 3 shows the oleic acid conversion with reaction time at various temperatures and ethanol/oleic acid molar ratio 6/1 with 5 wt.% of nay zeolite. time, min 0 20 40 60 80 100 120 140 160 o le ic a c id c o n ve rs io n 0.0 0.2 0.4 0.6 0.8 1.0 t=40° c t=50° c t=60° c t=70° c etoh/oil = 6/1 cat = 5% wt fig. 3, effect of the reaction time on oleic acid conversion by the esterification reaction at different temperature, 6/1: ethanol/oil molar ratio and 5 wt. % nay as shown in the figure 3, the conversion of oleic acid at 6/1 ethanol/oleic molar ratio and 5wt. % nay was 0.8 after 60 minutes and was 0.72 after 150 minutes with the same condition. at the beginning of the reaction the oleic acid conversion increased with temperature. according to the collusion theory [19], which is the famous theory described the chemical reaction, increasing in reaction temperature may causes an increase in molecule activity, which means that more molecules have more energy to react, and reduction in viscosity of reaction mixture (i.e. remarkable increasing of diffusivity). thus, increasing of temperature increases the possibility of the molecule to diffuse through the catalyst pores, reach to the active site of catalyst and react. but after 60 minutes the oleic acid conversion decreased because the water molecules may be clump in the pores of catalyst, due to the hydrophilic property of the zeolite [20], and that will increase the backward reaction. effect of ethyl alcohol/oil molar ratio on the oleic acid conversion the molar ratio of ethanol to oleic acid is one of the most important variables that affects the conversion of oleic acid. the experiments of esterification reaction of oleic acid with ethanol were carried out under various ethanol/oil molar ratios (3/1 and 6/1). figure 4 shows the conversion of oleic acid with reaction time at various ethanol/oleic acid molar ratio using 5 wt. % nay (as catalyst) at 70°c. time (min) 0 20 40 60 80 100 120 140 160 o le ic a c id c o n ve rs io n 0.0 0.2 0.4 0.6 0.8 1.0 etoh/oleic=3/1 etoh/oleic=6/1 temp=70 o c cat=5% wt fig. 4, effect of reaction time on oleic acid conversion by esterification reaction at different ethyl alcohol/oleic molar ratio, at the temperature 70 ° c and 5 wt.% nay it can be observed that the oleic acid conversion increased from 0.45 at molar ratio of 3/1 to 0.81 at a molar ratio of 6/1 after 60 min using 5 wt. % of nay at 70°c (fig. 4). the mechanism of an esterification reaction between a triglyceride and alcohol involves one mole of triglyceride for one mole of alcohol. the stoichiometric ratio is not used and an excess of alcohol is mandatory ammar s. abbas and rowaida n. abbas -available online at: www.iasj.net ijcpe vol.14 no.4 (december 2013) 39 to reach good conversion. usually, the molar ratio 6:1 is allowed to shift the equilibrium towards the formation of the product and enable to reach better conversion [21, 22]. increasing in ethanol/oleic mol. ratio in the range up to 6/1 causes increased in the conversion in oleic acid, because the esterification of oleic acid with ethanol is an equilibrium-limited chemical reaction and the position of equilibrium controls the amount of ester formed [23]. also, the increasing can be explained by the emulsion system changes from the dispersion of ethanol into oleic acid towards the dispersion of oleic acid into ethanol. this transformation results cause an increase in the interfacial area up to a point above which the interfacial area starts to decrease as the cavitations in ethanol phase is much easier than in oleic acid phase due to viscosity difference [24]. effect of catalyst amount on the oleic acid conversion the catalyst load effect on the oleic acid conversion is given in figure 5. the oleic acid conversion increased with increasing the catalyst load (from 2 to 5 wt. %). the reaction rate of esterification is directly proportional to the amount of a catalyst, due to the increase of active site numbers, so the catalyst is used to enhance the reaction rate and conversion. time (min) 0 20 40 60 80 100 120 140 160 o le ic a c id c o n ve rs io n 0.0 0.2 0.4 0.6 0.8 1.0 2% wt cat 5% wt cat 10% wt cat temp=70 o c etoh/oleic=6/1 fig. 5, effect of the reaction time on oleic acid conversion by esterification reaction at different catalyst load (nay), temperature 70 ° c and 6/1: ethanol /oleic molar ratio at catalyst weight present more than 5 wt. % the effect of catalyst load did not show any remarkable effect on oleic acid conversion, may be due to increasing the surface area of zeolite catalyst that causes more accumulation of water in the pores as a result of the hydrophilic action of the zeolite [25]. this accumulation of water increasing backward reaction (eq. 1). catalyst reuse the solid catalyst needs to be regenerated when they have been used for a period of time in order to have good performance. stopping the reaction and regeneration the catalyst is an expensive non-conventional operation [26]. the nay catalyst was reused after drying it at 100 o c for 24 hours (without regeneration). the conversion decreased from 0.81 (for fresh catalyst) to 0.56 (for reused catalyst), as shown in fig.6. time (min) 0 20 40 60 80 100 120 140 160 o le ic a c id c o n ve rs io n 0.0 0.2 0.4 0.6 0.8 1.0 normal use reuse cat temp=70 o c etoh/oleic=6/1 fig. 6, effect of the reaction time on oleic acid conversion by the esterification reaction using fresh and reuse nay at the temperature 70 ° c and 6/1: ethanol /oleic molar ratio kinetic of oleic acid esterification kinetic obtained from laboratory unit are usually played an important role in modeling and scale up designs for new biodiesel production units. the data obtained by differential method of analysis has been used to find a favorable kinetic model for oleic acid esterification. kinetic study and simulation of oleic acid esterification over prepared nay zeolite catalyst 40 ijcpe vol.14 no.4 (december 2013) -available online at: www.iasj.net the differential method of analysis deals directly with the differential rate equation to be tested, evaluating all terms in the equation including the derivative -ra, and testing the goodness of fit of the equation with experiment. the conversion of oleic acid (x) fitted by the third order polynomial degree formula according to the time at certain temperature, and then finding the rate coefficients (k1 and k2) as well as the orders of the reactants and products materials (n1, m1, n2 and m2) using least squares method for the suggested reaction kinetics equation (eqs. 1 to 5). ↔ …(1) ...(2) …(3) ...(4) ...(5) the arrhenius law [19]: ( ) …(6) a plot of ln k vs. 1/t of eq. 6 gives a straight line, with slope for -e/r to find activation energy for forward reaction and backward reaction (figs. 7 and 8). the values of constants in the esterification reaction of oleic acid are summarized in table 1. the obtained values of rate coefficients, equilibrium constant, orders of reactants and products materials, heat of reactions and activation energy were used to simulate the results. predicted values calculated from empirical model and experimental data are shown in figure 9. statistical analysis of the experimental data shows that the solution of the model (eq. 5) is proportional with the experimental results. the statistical analyses are summarized in table 2. ln k 1 = -5135.3/t+11.19 1/t 0.0029 0.0030 0.0031 0.0032 ln k 1 -5.4 -5.2 -5.0 -4.8 -4.6 -4.4 -4.2 -4.0 -3.8 -3.6 fig. 7, plot of ln k1 vs. 1/t resulting from the esterification of oleic acid for forward reaction ln k 2 = -2071/t+1.497 1/t 0.0029 0.0030 0.0031 0.0032 ln k 2 -5.2 -5.0 -4.8 -4.6 fig. 8, plot of ln k2 vs. 1/t resulting from the esterification of oleic acid for backward reaction table 1, constant values of the esterification reaction kinetic model constant value 72402 (j/mole) 42692 4.5 (j/mole) 17218 1 1 1.2 1 16089.3 (j/mole) 25474 ammar s. abbas and rowaida n. abbas -available online at: www.iasj.net ijcpe vol.14 no.4 (december 2013) 41 real production rate, .mol/min 0.000 0.001 0.002 0.003 0.004 0.005 p re d ic te d p ro d u c ti o n r a te , m o l/ m in 0.000 0.001 0.002 0.003 0.004 0.005 fig. 9, experimental and predicted values of apparent rate constant by using suggested model of esterification of oleic acid with 6/1: ethanol/oleic molar ratio, 5% nay as catalyst and temperature range from 40 to 70 ° c table 2, statistical analysis of the model statistical analysis value standard error 7.6*10 -4 average relative error, % 1.53 standard deviation (s) 6.5*10 -4 variance 4.3*10 -7 confidence level 0.95 simulation results simulation for the behavior of batch and plug flow reactors in different operating modes (adiabatic and isothermal) was carried out at the best conditions. these selected conditions were 70°c (high temperature gives higher conversion), 60 minutes reaction time 6/1 ethanol/oleic molar ratio, 5 wt. % of nay as catalyst. the simulation results are reported in table 3. as reported, simulated results of the isothermal operating mode are approximately identical to the experimental results. the simulated results of the adiabatic operating mode show decreasing in oleic acid conversion, this lowering is due to the temperature decreasing of the reaction mixture through the endothermic reaction of esterification (∆hr =145.19 kj/mol). table 3, highest conversion results at the best conditions from experimental and simulated results of isothermal and adiabatic operation at 60 minutes reaction time reactor/operating mode conversion c18h34o2, kmol/m 3 c2h6o, kmol/m 3 c20h38o2, kmol/m 3 h2o, kmol/m 3 initial values 0 1.00 4.44 0.00 1.25 plug or batch/ isothermal 0.80 0.20 3.64 0.79 2.05 experimental batch/ isothermal 0.81 0.19 3.63 0.81 1.96 plug or batch/ adiabatic 0.76 0.24 3.68 0.76 1.91 conclusion 1. the maximum conversion of oleic acid was 0.81 at 6/1 of ethanol/oleic acid molar ratio after 60 minutes, 70° c and 5% nay. 2. increasing the ethanol/oleic acid molar ratio from 3 to 6 increases the conversion of oleic acid. 3. the activation energies for the suggested kinetic model were 42692j/mole for the forward reaction and 17218 j/mole for the backward reaction. 4. the simulation results for isothermal batch and plug flow reactors show no remarkable differences from the experimental results. 5. adiabatic operating mode results show lower conversion by 5% than isothermal operating mode results. nomenclatures -ra = dx/dt reaction rate of oleic acid a = oleic acid, b= ethanol, c= ester, d= water k = rate coefficient of reaction. 1= forward reaction, 2= backward reaction, n and m are the reaction orders. n1 for oleic , m1 for ethanol, n2 for ester, m2 for water. kinetic study and simulation of oleic acid esterification over prepared nay zeolite catalyst 42 ijcpe vol.14 no.4 (december 2013) -available online at: www.iasj.net ca, cb, cc, cd = reactants and products moles at any time. cae, cbe, cce, cde = reactants and products moles at equilibrium time. e1 = activation energy for forward reaction (j/mole) e2 = activation energy for backward reaction (j/mole) ko1=frequency factor ((mol) -2.2 /minute) for forward reaction ko2 = frequency factor for backward reaction ((mol) -2.0 /minute) references 1amigun b., sigamoney r., blottnitzh.v.,“commercialization of biofuel industry in africa: a review.”renew. sustain. energy rev., vol.12, pp.690-711, (2008). 2enweremadu cc, mbarawa mm, “technical aspects of production and analysis ofbiodiesel from used cooking oil – a review.” renewable and sustainable energy reviews, vol.13, pp.2205–24, (2009). 3leung dyc, wu x, leung mkh. ”a review on biodiesel production using catalyzed transesterification”. applied energy, vol. 87, pp.1083–95, (2010). 4chen y., xiao b., chang j., fu y., lv p, wang x., “synthesis of biodiesel from waste cooking oil using immobilized lipase in fixed bed reactor.”, energy conversion and management, vol. 50, pp.668– 73,(2009). 5guerreiro l, pereira pm, fonseca im, martin-aranda rm, ramos am, dias jml,et al., “pva embedded hydrotalcite membranes as basic catalysts for biodiesel synthesis by soybean oil methanolysis.” catalysis today, vol.156, pp.191–7, (2010).technology,90:770–7, 2009. 6math m.c., kumar s.p., chetty sv, “technologies for biodiesel production from used cooking oil – a review.” energy for sustainable development, vol.14, pp.339–45, (2010). 7zabeti m, daud wmaw, aroua mk, “activity of solid catalysts for biodiesel production: a review”, fuel processing, vol.90, pp.770–7, (2009). 8hoydonckx, h.e., de vos, d.e., chavan, s.a. and jacobs, p.a.,“esterification and transesterification of renewable chemicals: catalytic conversion of renewables”. guest editors: herman van bekkum and pierre gallezot. topics in catalysis, vol.27, pp. 83-96,(2004). 9ma, f. and hanna, m.a., “biodiesel production: a review.” bioresource technology, vol. 70(1), pp. 1-15, (1999). 10hattori, h. “solid base catalysts: generation of basic sites and application to organic synthesis”. applied catalysis a: general. vol. 222(1-2), pp.247-259, (2001). 11ono, y. and baba, t. “selective reactions over solid base catalysts”. catalysis today. vol. 38(3), pp. 321-337(1997). 12abbas a.s. and abbas s.m., “kinetic study and simulation of oleic acid esterification in different type of reactors”, iraqi journal of chemical and petroleum engineering, vol.14 no.2, pp. 13 20, (2013). 13mat r., ling o.s., johari a., mohamed, m., “in situ biodiesel production from residual oil recovered from spent bleaching earth”. bulletin of chemical reaction engineering and catalysis, vol. 6(1), pp. 53-57, (2011). 14lópez, d.e., goodwin, j.j.g., bruce, d.a. and lotero, e. “transesterification of triacetin with methanol on solid acid and base catalysts”, applied catalysis ammar s. abbas and rowaida n. abbas -available online at: www.iasj.net ijcpe vol.14 no.4 (december 2013) 43 a: general, vol.295 (2), pp.97-105. (2005). 15furuta, s., matsuhashi h., arata, k.,” biodiesel fuel production with solid super acid catalysis in fixed bed reactor under atmospheric pressure”. catal. commun., vol. 5, pp.721–723, (20040. 16mat, r.,samsudin r.a., mohamed m.,joharia.,“solid catalysts and their application in biodiesel production”, vol.7 (2), 142 – 149,(2012). 17mbaraka, i.k., shanks, b.h.,“conversion of oils and fats using advanced mesoporous heterogeneous catalysts”. j. am. oil chem. soc. 83, pp.79–91, (2006). 18dossin, t.f., reyniers, m.f., berger, r.j., marin, g.b. “simulation of heterogeneously mgo-catalyzed transesterification for fine-chemical and biodiesel industrial production”. appl. catal. b: gen., vol.67, pp.136–148, (2006). 19hill, c. g. jr., “an introduction to chemical engineering kinetics and reactor design”, john willy and sons, 1977. 20flanigen, e. m., broach, r. w. and steph, “zeolites in industrial separation and catalysis”, edited by santi kulprathipanja, wileyvch verlag gmbh and co. kgaa, weinheim, (2010). 21freedman, b., pryde, e. and mounts, t., "variables affecting the yields of fatty esters from transesterified vegetable oils", journal of the american oil chemists' society, vol. 61, pp. 1638-1643, (1984). 22freedman, b., butterfield, r. o. and pryde, e. h., "transesterification kinetics of soybean oil", journal of the american oil chemists' society, vol. 63, pp. 1375-1380, (1986). 23zubir m.i., chin s.y., “kinetic of modified zirconiz-catalyzed heterogeneous esterification reaction for biodiesel production”, journal of applied sciences, vol.10 (21), pp.2584-2589, (2010). 24mahamuni, n. n and adewuyi, y. g., “application of tanguchi method to investigate the effect of process parameters on the transesterification of soybean oil using high frequency ultrasound”, energy fuels, vol.24, pp.21202126, (2010). 25zubir m.i., chin s.y., "kinetic of modified zirconiz-catalyzed heterogeneous esterification reaction for biodiesel production", journal of applied sciences, vol.10 (21), pp.2584-2589, 2010. 26marchetti j.m., miguel a.u., errazu a.f., “heterogeneous esterification of oil with high amount of free fatty acids”, fuel, vol.86, pp.906-910, (2007). available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol. 24 no.2 (june 2023) 97 – 105 eissn: 2618-0707, pissn: 1997-4884 *corresponding author: name: ghanim m. farman, email: ghanimzubaidy@uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. comparative study between different oil production enhancement scenarios in an iraqi tight oil reservoir ghanim m. farman a, *, ali khaleel farouk b, and ayad a. alhaleem a a petroleum engineering department, college of engineering, university of baghdad, iraq b north oil company, kirkuk, iraq abstract this paper presents a comparative study between different oil production enhancement scenarios in the saadi tight oil reservoir located in the halfaya iraqi oil field. the reservoir exhibits poor petrophysical characteristics, including medium pore size, low permeability (reaching zero in some areas), and high porosity of up to 25%. previous stimulation techniques such as acid fracturing and matrix acidizing have yielded low oil production in this reservoir. therefore, the feasibility of hydraulic fracturing stimulation and/or horizontal well drilling scenarios was assessed to increase the production rate. while horizontal drilling and hydraulic fracturing can improve well performance, they come with high costs, often accounting for up to 100% of the total well cost. to ensure economically viable flow rates and achieve maximum ultimate oil recovery, a technical and economic comparative study was conducted. the results indicate that hydraulic fracturing offers promising outcomes, with a total oil production of 153,816 mbbl over 30 years from 25 fractured wells, resulting in a final net present value (npv) of 3,583.32 mm$. in contrast, the planned two horizontal wells exhibit lower eventual production and npv compared to the majority of fractured wells. however, the 2000 m lateral section of well hf00y-s00yh shows a slightly higher npv. considering the operational benefits and profitability, hydraulic fracturing should be seriously considered for the further development of the saadi reservoir. this comparative study provides valuable insights into the most effective approach for enhancing oil production in tight reservoirs like saadi, balancing the technical feasibility and economic viability of different stimulation scenarios. the findings can guide decision-making processes and contribute to maximizing oil recovery in similar challenging reservoirs. keywords: hydraulic fracturing; horizontal wells; stimulation; oil recovery; saadi reservoir. received on 05/04/2023, received in revised form on 28/04/2023, accepted on 06/05/2023, published on 30/06/2023 https://doi.org/10.31699/ijcpe.2023.2.11 1introduction the oil industry is constantly evaluating and creating new oil and gas reservoirs to meet the increasing claim for oil components. unconventional reservoirs, which span a large area and utilize special techniques or extensive stimulation treatments to extract significant amounts of hydrocarbons, are now the primary focus for resource development [1]. there are various techniques and treatments to enhance the oil recovery from tight oil reservoirs including: acid fracturing, hydraulic fracturing, fishbone wells, horizontal wells, deviated wells and matrix acidizing. acid fracturing of vertical wells was less effective in stimulating production in tight oil reservoirs since this method results in shorter fracture height and length [2, 3]. although, fishbone wells outperforms horizontal and deviated wells in saadi reservoir as it gives higher oil production rates for extended period. the complexity of drilling fishbone wells makes it difficult to be achieved [4]. also, deviated wells need high kickoff points and it is usually being drilled instead of vertical wells in areas where there is difficulty to drill vertical wells [5]. in addition, the production of hydrocarbons from unconventional reservoirs is not primarily influenced by the properties of the rock matrix, but rather by the presence of secondary fractures and, in some cases, an enhanced permeability zone created through stimulation techniques [6]. the initial performance of the wells that penetrates saadi reservoir was high after the treatments, suggesting a favorable effect of the implemented treatments. the performance of the wells decreased quickly by 65% after 3 months. during this time, there was intermittent oil production and some of the wells were shut-in. as a result, and because of the poor petrophysical characteristics of saadi reservoir, matrix acidizing failed in enhancing production from such tight oil reservoirs [7]. therefore, to bypass the complexity of fishbone and deviated wells and the underwhelmed production of acid fracturing and matrix acidizing treatments, hydraulic fracturing of vertical wells and drilling horizontal wells scenarios are proposed for developing saadi reservoir. there are several advantages and restrictions associated with each option. thus, hydraulic fracturing and horizontal wells methods must be closely examined to choose the better scenario, since they have a big impact on how the reservoir will perform. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:ghanimzubaidy@uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2023.2.11 g. m. farman et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 97 105 98 the focus of this study is the saadi formation, located in the halfaya oil field, which is the thickest and most widespread formation within the late turonian-early campanian sequence. it consists of two units, the nonreservoir saadi a and the reservoir saadi b, which is the primary tight oil reservoir in the field with a thickness of 77 meters. the saadi formation is deposited over the tanuma formation and below the hartha formation, and is predominantly composed of limestone [8]. although it is a carbonate oil reservoir with medium-sized pores and narrow pore throats, it has poor petrophysical characteristics. the saadi formation forms an anticline structure (fig. 1). it is clear that top of the reservoir is approximately at 2775 m. the permeability (k) of saadi reservoir is (0.02-5) md, while the porosity is (0.08-0.25). the original oil in place (ooip) is estimated to be 4585 mmbbl, which represents 22.5% of halfaya field’s ooip. however, only 412 mmbbl of this ooip is stored in the reservoir where k > 2 md; and 187 mmbbl when k > 5 md, which represents only 3% of halfaya field ooip. the remaining 3986 mmbbl of the ooip is accumulated in saadi reservoir where k < 1.3 md and represents 19.5% of halfaya field’s ooip. the average oil recovery factor of saadi reservoir is 1.3% [9]. fig. 1. 3d surface map for top of saadi b [7] 2materials and methods 2.1. hydraulic fracturing the standard hydraulic fracture treatment is designed to maximize well stimulation by providing optimal fracture length and conductivity. the process of hydraulic fracturing involves carefully considering various design parameters such as the type and size of fracturing fluid, the type and concentration of proppant, and the pumping rate [9]. when designing a hydraulic fracturing treatment, it is important to prioritize the contact with the reservoir's capacity over the generated fracture half-length or conductivity. the length of the fracture produced has an impact on the effective fracture length and due to the complexity of the porosity-permeability and fracturing system, accurate flow modeling is critical for efficient treatment [6, 10]. a. selection of fracturing fluids the selection of the fracturing fluid utilized is dependent on the brittleness and permeability of the formation. formations with high permeability are typically stimulated with viscous fracturing fluids to create wider fractures. on the other hand, lowpermeability formations can impede fluid flow, leading to unfractured rocks. in addition, increased rock ductility or reduced brittleness require larger fracture openings to maintain the fractures' permeability once pressure is removed. brittle reservoirs with poor permeability require more aggressive fracturing. it is important to note that any deposition in the reservoir will reduce permeability [11], necessitating the injection of greater fluid volume with lower viscosity, such as slick-water or guar fluid [12]. increasing the amount of fracturing fluid used causes an increase in fracture length [13]. the viscosity and temperature of the saadi formation are compatible with gel fracturing fluid like guar_200 f° and slickwater_180 f° (where guar and slickwater are types of fracturing fluid operating at different reservoir temperature). b. selection of proppants to keep the fracture open and provide a pathway for reservoir fluids to reach the wellbore, sand (proppant) is injected with fluid. the size of the proppant has a significant impact on the fracture's permeability, and a homogeneous and larger proppant size achieves higher permeability [13, 14]. g. m. farman et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 97 105 99 the proppant's transportability and strength also influence the fracture permeability, as higher transportability allows for deeper proppant distribution, while proppant strength is critical to avoid smashing under fracture closure stress. ceramic proppants with varying densities, compressive strengths, and size and shape control are used to create extremely homogeneous grains [15]. the viscosity of the fluid and friction against the pipe walls also affect energy loss in fluid and proppant transmission in pipelines, leading to more pumping power consumption [16]. a typical trend in fracture fluid types, volumes, and complexity based on rock characteristics is shown in fig. 2. when rock brittleness increases, permeability decreases, and the rock is highly fractured, low viscosity, high-volume, and pumping rate fracturing fluids are recommended, with lower proppant volume and concentration [17]. asymmetrical fractures with smaller openings tend to be more complex, and the chosen lowdensity and high-density ceramic proppants provide the highest conductivity for stresses over 6000 psi. fig. 2. rock characteristics, fracturing treatment, and fracture response [17] c. selection of fracturing fluids pumping rates fracturing fluid pumping rates from 18 to 44 bpm were employed. fig. 3 illustrates the optimal pumping rate utilizing the guar fracturing fluid. it can be noticed that the longest fracture is generated at pumping rate equal to 31.5 bmp. as the pumping rate goes above 31.5 bpm, the fracture is shortened enabling additional vertical propagation. therefore, pumping rate of 31.5 is the optimal rate. fig. 3. optimized pumping rate d. hydraulic fracturing designs the study employs two hydraulic fracturing designs to evaluate hydrocarbon production in 25 wells within the study region.  design a uses guar_200 f° fracturing fluid with high-density ceramic proppants at a pumping rate of 31.5 bpm.  design b utilizes slickwater_180 f° fracturing fluid with low-density ceramic proppants at the same pumping rate. e. productivity of fractured wells the steady-state flow oil rate for fractured wells is found as per eq. 1 [5]. g. m. farman et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 97 105 100 (1) where q is flow rate, k is permeability, h is height of fracture, pe is reservoir pressure at re, pwf is bottom hole flowing pressure, bo is oil formation volume factor, μo is oil viscosity, re is drainage radius, rw is well-bore radius and sf is skin factor. 2.2. horizontal wells increasingly, horizontal wells have been employed in low-permeability reservoirs due to the advancement of drilling technology as well as the decrease in drilling costs [18]. each horizontal well drains a large portion of the reservoir, resulting in higher output from pay zones. the well’s orientation, lateral section length, pay zone thickness, petrophysical characteristics, compressibility and boundary conditions all influence the output of a horizontal well. however, the length of the horizontal wellbore is the most important factor in determining horizontal well performance [19]. the horizontal well's lateral length may enable contact with numerous fractures, significantly increasing production [20]. two horizontal wells namely hf00x-s00xh and hf00ys00yh are proposed to be drilled in halfaya oil field with target in saadi formation. to evaluate the production performance and economics outcomes of various lateral unfractured horizontal wells, the oil rate is fixed at the same plateau oil rate of the fractured wells to compare the outcomes of the fractured vertical wells and horizontal wells more precisely. the supposed lateral lengths are 500, 750, 1000, 1500 and 2000 m for each well.  productivity of horizontal wells many equations to estimate the productivity of horizontal wells were presented in the literature. the modified joshi equation is used to evaluate the production rate of horizontal wells [21, 22]. (2) where h is pay zone thickness, kh is horizontal permeability, kv is vertical permeability, l is lateral length, a is modified joshi factor, s is skin factor and fo is frictional pressure correction factor. 2.3. economic comparison when making a choice on a project, the economic analysis is critical. net cash flow (ncf, mm$) is a function of cumulative hydrocarbon production over the entire project period, capital expenditure (capex, mm$) and operational expenditure (opex, mm$). in the context of a particular capex composed of drilling cost plus the fracturing treatment cost and opex which is the monthly well cost over the entire production period, the ncf may be seen as a function of the cumulative hydrocarbon production. also, cumulative hydrocarbon production is a function of the fracture length, the fracture height and lateral section length. hence, ncf of the fractured wells is a function of the fracture geometry whereas ncf of horizontal wells is a function of lateral section length [23]. the entire cost in this study is made up of drilling costs, including completion costs, and stimulation costs. the cost of vertical wells is constant for each well, however the cost of lateral drilling varies according to the lateral length specified for the horizontal well section. it is composed of a fixed cost component and a variable cost component. due to small variation in total depth of all other wells in the project, vertical wells drilling and completion costs are fixed to 5 mm$. fracturing fluid unit and proppant unit costs are 1 $/gal and 0.4 $/lb, respectively. fixed fracturing job cost is assumed to be 400000 $. cost of horizontal well with lateral length of 500 m is 6.5 mm$ and increasing 0.35 mm$ every 500 m of extra lateral length. monthly well cost is assumed at 1500 $/month. oil price and gas price are 60 $/bbl and 4$/mscf, respectively. production forecasting for 10950 days (30 years) is estimated. the npv for each well and design in the project is estimated assuming the discount rate at 15%. the two scenarios are compared based on cumulative production and npv results. the greater the cumulative production, and hence the greater the npv, the more favorable the potential scenario. the net present value (npv) of fractured vertical wells for n years is calculated using eqs. 3 through 11. for horizontal wells, these equations are used realizing that the capex is the well drilling cost including all associated operations cost [23]. (3) ncf = gross revenue total cost, (4) gross revenue = cumulative production × price, (5) total cost = opex + capex, (6) opex = monthy well cost × no. of months, (7) capex = drilling cost + fracturing cost, (8) fracturing cost = fracturing fluid cost + proppant cost + fixed job cost, (9) fracturing fluid cost = fracturing fluid volume × price per fracturing fluid volume unit, (10) proppant cost = proppant mass × price per proppant mass unit, (11) 𝑞 = 𝑘𝐻ℎ 𝑝𝑒 − 𝑝𝑤𝑓 141.2𝐵𝑜𝜇𝑜 𝑙𝑛⁡ 𝑎 + 𝑎2 − (𝐿/2)2 𝐿/2 + 𝑘𝐻 𝑘𝑉 ℎ 𝐿 𝑙𝑛⁡ 𝑘𝐻 𝑘𝑉 ℎ 𝑟𝑤 𝑘𝐻 𝑘𝑉 + 1 + 𝑆 . 𝐹𝑜 𝑁𝑃𝑉 =   𝑁 𝑖=1 𝑁𝐶𝐹 (1 − 𝐷𝑖𝑠𝑐𝑜𝑢𝑛𝑡 𝑅𝑎𝑡𝑒)𝑖 𝑖 g. m. farman et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 97 105 101 3results design a involved pumping a total of 53,475.9 gallons of clean fluid, 55,870.5 gallons of slurry, and 72,013 pounds of proppant through the perforations. the resulting fracture had a half-length of 220 meters, a height of 178 meters, an average width of 0.054 inches, and a maximum width of 0.129 inches. design b required pumping a total of 53,354.4 gallons of clean fluid, 56,404.5 gallons of slurry, and 72,013 pounds of proppant through the perforations, resulting in a fracture with a half-length of 208.8 meters, a height of 98 meters, an average width of 0.047 inches, and a maximum width of 0.113 inches. fig. 4 and fig. 5 illustrate the proppant concentration for designs a and b, respectively, for well hf-55. fig. 4. proppant concentration (lb/ft2) for design a of well hf-55 fig. 5. proppant concentration (lb/ft2) for design b of well hf-55 3.1. production forecast for fractured wells and horizontal wells the oil rates for each fractured vertical wells in the project over 30 years are illustrated in fig. 6 and fig. 7 for designs a and b, respectively. also, the oil rates for horizontal wells are presented in fig. 8. according to the findings of the fracturing models, the plateau oil rate for the majority of the wells was 1239 bbl/day. as a result, the horizontal wells are compelled to produce largely at this rate. when compared to fractured wells, the horizontal wells will only be able to produce at the plateau rate for a short period of time which not exceeds 2 years at the longest lateral section. even with all tested lateral lengths of hf00y-s00yh and hf00xs00xh, the total oil volume is less than 1000 mbbl at an average daily rate less than 60 bbl/day. since the oil produced is less than the majority of fractured wells, it follows that the gas produced is less, too. fig. 6. oil rates for fractured vertical wells design a fig. 7. oil rates for fractured vertical wells design b fig. 8. oil rate for horizontal wells the stacked histogram in fig. 9 depicts the project's cumulative oil volumes and npv for all wells analyzed at various treatment configurations. 4discussion the results of design (a) for well hf-55 indicate that the fracture height propagated upward towards the hartha formation and downward towards the tanuma formation and yields the highest rates and cumulative volumes of oil and gas over the entire 10950 days (30 years) of the production forecasting. the design's final oil was 7858.360 mbbl, with a plateau peak oil rate of 1239 bbl/day over 4044 days and an average oil rate of 718 bbl/day. furthermore, the npv analysis reveals that design (a) yields 170.356 mm$. the design (b) for well hf-55, in which better fracture height confinement has been gained; results in final oil volume of 2171.720 mbbl, g. m. farman et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 97 105 102 with a plateau peak oil rate of 1239 bbl/day over 593 days and an average oil rate of 198 bbl/day. likewise, the npv analysis reveals that design (b) yields 82.032 mm$. the hydrocarbon production and npvs for 25 wells show promising results since utilizing the design (a) gives 153816 mbbl total oil production over 30 years from 25 wells with a final npv of 3583.32 mm$. on the other hand, a total of 79957.7 mbbl of oil with a final npv of 2373.772 mm$ is achieved when the design (b) is being used. the planned horizontal wells have a lower eventual production and npv than the majority of fractured wells, with the exception of the 2000 m lateral section of well hf00y-s00yh, which has a slightly higher npv. the results of fractured vertical wells show accepted oil production and npv in view of previous researches and actual well production data of saadi reservoir. these findings assist in circumventing the intricacy of fishbone and deviated wells, as well as the disappointing output of acid fracturing and matrix acidizing treatments. therefore, hydraulically fractured wells outperform horizontal wells and should be considered for further development of saadi reservoir keeping the operational benefits and profitability in balance. recognizing the significance of extended horizontal wells and hydraulic fracturing of vertical wells in enhancing production of halfaya oil field, acid and hydraulic fracturing of horizontal wells will be the emphasis of the future phases for optimizing output from the field, particularly from the saadi reservoir. fig. 9. horizontal wells and fractured vertical wells final cumulative oil production and npv comparison 5conclusions investigation for treatments and solutions are necessary in order to obtain and maintain commercial production in a tight oil reservoir like saadi reservoir which was this study scope. optimal treatment designs created for horizontal wells and fractured vertical wells. the following are concluded:  production forecast for fractured wells show dramatic increase in hydrocarbon rates and cumulative production in comparison with unfractured wells.  longer plateau could be conserved with higher cumulative hydrocarbon output for majority of the fractured vertical wells.  also, the economic analysis gives promising results of high npv for majority of the fractured vertical wells in the project area.  the proposed unfractured horizontal wells at various lateral section lengths show that hydrocarbon rate and plateau periods are much smaller than fractured vertical wells. hence the wells reach very low production rates very fast.  the npv of the horizontal wells show that for 2000 m lateral sections the well could be economical. otherwise, these wells are abounded fast and the npv are not accepted economically.  comparing the two scenarios, the majority of the fractured vertical wells shows higher plateau rate, period and npv’s than all proposed horizontal wells.  therefore, the optimal strategy for developing such a low permeability reservoir is to employ fractured vertical wells rather than drilling horizontal wells. abbreviations and nomenclatures ooip, original oil in place, mmbbl; k, permeability, md; kh, horizontal permeability, md; kv, vertical permeability, md; q, production rate, bpm; h, height of fracture, m; pe, reservoir pressure, psi; pwf, bottom hole flowing pressure, psi; bo, oil formation volume factor, reservoir bbl/ standard bbl; μo, oil viscosity, cp; re, drainage radius, m; rw, well-bore radius, inches; sf, skin factor, dimensionless; l, lateral length, m; fo, frictional pressure correction factor; a, modified joshi factor; ncf, net cash flow, mm$; npv, net present value, mm$; scf, standard cubic feet; gal, gallons; lb, pounds; hf, halfaya wells prefix; capex, capital expenditure, mm$; opex, operational expenditure, mm$. g. m. farman et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 97 105 103 references [1] holditch, s. a. (2006). tight gas sands. journal of petroleum technology, 58, 86-93. https://doi.org/10.2118/103356-jpt [2] al-sudani, j. a., and husain, k. m. (2017). evaluation of acid and hydraulic fracturing treatment in halfaya oil field-sadi formation. iraqi journal of chemical and petroleum engineering, 18, 25-33. [3] alameedy, u., alhaleem, a.a., isah, a. et al. (2022). effect of acid treatment on the geomechanical properties of rocks: an experimental investigation in ahdeb oil field. j petrol explor prod technol 12, 3425-3441. https://doi.org/10.1007/s13202-02201533-x [4] manshad, a.k., dastgerdi, m.e., ali, j.a. et al. (2019). economic and productivity evaluation of different horizontal drilling scenarios: middle east oil fields as case study. j petrol explor prod technol 9, 2449-2460. https://doi.org/10.1007/s13202-0190687-9 [5] joshi, s. d (1988). augmentation of well productivity with slant and horizontal wells (includes associated papers 24547 and 25308). journal of petroleum technology, 40, 729-739. https://doi.org/10.2118/15375-pa [6] barree, r. d., cox, s. a., miskimins, j. l., gilbert, j. v., and conway, m. w. (2015). economic optimization of horizontal-well completions in unconventional reservoirs. spe production & operations, 30, 293-311. https://doi.org/10.2118/168612-pa [7] jassam, s. a., and al-fatlawi, o. (2023). development of 3d geological model and analysis of the uncertainty in a tight oil reservoir in the halfaya oil field. the iraqi geological journal, 56(1b), 128-142. https://doi.org/10.46717/igj.56.1b.10ms-2023-2-18 [8] noori, a. k., lazim, s. a., and ramadhan, a. a. (2019). geological model of the tight reservoir (sadi reservoir-southern of iraq). journal of engineering, 25(6), 30-43. https://doi.org/10.31026/j.eng.2019.06.03 [9] shaoul, j. r., ross, m. j., spitzer, w. j., wheaton, s. r., mayland, p. j., & singh, a. p. (2007). massive hydraulic fracturing unlocks deep tight gas reserves in india. european formation damage conference. https://doi.org/10.2118/107337-ms [10] farouk, a. k., and al-haleem, a. a. (2022). integrating petrophysical and geomechanical rock properties for determination of fracability of an iraqi tight oil reservoir. the iraqi geological journal, 55(1f), 81-94. https://doi.org/10.46717/igj.55.1f.7ms-2022-06-22 [11] farhan, l. w., almahdawi, f. h., and hammadi, a. s. (2020). dissolving precipitated asphaltenes inside oil reservoirs using local solvents. iraqi journal of chemical and petroleum engineering, 21(1), 45-52. https://doi.org/10.31699/ijcpe.2020.1.7 [12] cipolla, c. l., warpinski, n. r., mayerhofer, m. j., lolon, e., & vincent, m. c. (2008). the relationship between fracture complexity, reservoir properties, and fracture treatment design. spe annual technical conference and exhibition. https://doi.org/10.2118/115769-ms [13] xu, s., guo, j., feng, q., ren, g., li, y., and wang, s. (2022). optimization of hydraulic fracturing treatment parameters to maximize economic benefit in tight oil. fuel, 329, 125329. https://doi.org/10.1016/j.fuel.2022.125329 [14] kolawole, o., esmaeilpour, s., hunky, r., saleh, l., ali-alhaj, h. k., and marghani, m. (2019). optimization of hydraulic fracturing design in unconventional formations: impact of treatment parameters. in spe kuwait oil & gas show and conference. onepetro. https://doi.org/10.2118/198031-ms [15] blyton, c. a., gala, d. p., and sharma, m. m. (2015). a comprehensive study of proppant transport in a hydraulic fracture. in spe annual technical conference and exhibition. onepetro. https://doi.org/10.2118/174973-ms [16] abdulrazak, a. a., al-khatieb, m., and faris, h. a. (2015). problems of heavy oil transportation in pipelines and reduction of high viscosity. iraqi journal of chemical and petroleum engineering, 16(3), 1-9. [17] rickman, r., mullen, m., petre, j., grieser, w., & kundert, d. (2008). a practical use of shale petrophysics for stimulation design optimization: all shale plays are not clones of the barnett shale. 2008 spe annual technical conference & exhibition. https://doi.org/10.2118/115258-ms [18] khudhair, s., and al-mahdawi, f. h. (2022). optimization of drilling well design: a review. iraqi journal of chemical and petroleum engineering, 23(4), 91-99. https://doi.org/10.31699/ijcpe.2022.4.11 [19] guo, b., zhou j. , liu y., and ghalambor .a. (2007). a rigorous analytical model for fluid flow in drainholes of finite conductivity applied to horizontal and multilateral wells. production and operations symposium. https://doi.org/10.2118/106947-ms [20] yuan, g., dwivedi, p., kwok, c. k., and malpani, r. (2017). the impact of increase in lateral length on production performance of horizontal shale wells. in spe europec featured at 79th eage conference and exhibition. onepetro. https://doi.org/10.2118/185768-ms https://doi.org/10.2118/103356-jpt https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/69 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/69 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/69 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/69 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/69 https://doi.org/10.1007/s13202-022-01533-x https://doi.org/10.1007/s13202-022-01533-x https://doi.org/10.1007/s13202-019-0687-9 https://doi.org/10.1007/s13202-019-0687-9 https://doi.org/10.2118/15375-pa https://doi.org/10.2118/168612-pa https://doi.org/10.46717/igj.56.1b.10ms-2023-2-18 https://doi.org/10.31026/j.eng.2019.06.03 https://doi.org/10.2118/107337-ms https://doi.org/10.46717/igj.55.1f.7ms-2022-06-22 https://doi.org/10.31699/ijcpe.2020.1.7 https://doi.org/10.2118/115769-ms https://doi.org/10.1016/j.fuel.2022.125329 https://doi.org/10.2118/198031-ms https://doi.org/10.2118/174973-ms https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/257 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/257 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/257 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/257 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/257 https://onepetro.org/conference-paper/spe-115258-ms https://doi.org/10.31699/ijcpe.2022.4.11 https://doi.org/10.2118/106947-ms https://doi.org/10.2118/185768-ms g. m. farman et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 97 105 104 [21] joshi, s. d. (1986). augmentation of well productivity using slant and horizontal wells. in spe annual technical conference and exhibition. onepetro. https://doi.org/10.2118/15375-ms [22] farman, g. m., and abdulamir, m. r. (2014). formulation of new equation to estimate productivity index of horizontal wells. iraqi journal of chemical and petroleum engineering, 15(2), 6173. [23] jahn, f., cook, m., and graham, m. (2008). chapter 14 petroleum economics. developments in petroleum science, 55, 337-364. https://doi.org/10.1016/s03767361(07)00014-3 https://doi.org/10.2118/15375-ms https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/278 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/278 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/278 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/278 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/278 https://doi.org/10.1016/s0376-7361(07)00014-3 https://doi.org/10.1016/s0376-7361(07)00014-3 g. m. farman et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 97 105 105 يقض عراقي نفطي حقل في المختلفة النفط إنتاج تعزيز سيناريوهات بين مقارنة دراسة 1 الرزاق عبد الحليم عبد اياد و ،2فاروق خليل علي ،، *1 فرمان مديح غانم العراق، جامعة بغدادقسم هندسة النفط، كلية الهندسة، 1 العراق كركوك، الشمال، نفط شركة 2 الخالصة ذات لمكامنا في اآلبار أداء لتحسين المتاحة الخيارات من األفقية اآلبار وحفر النفط آبار تشقيق خيار يعتبر تياراخ تم الدراسة، هذه في. الصغير الهيدروكربوني العمود ذات والمكامن الضعيفة البتروفيزيائية الخصائص السعدي تكوين يصنف. جيدة غير مواصفات ذو نفطي كمكمن العراقي الحلفاية حقل في النفطي السعدي مكمن بتروفيزيائية خصائص مع صغيرة فجوات وحلقات النفاذية ومنخفض الحجم متوسطة فجوات ذو كاربوني كمكمن تم التي بالتحميض، واالنعاش بالحامض التشقيق مثل المكمن، إلنعاش السابقة االختيارات أدىت. ضعيفة أدت قدل. األفقية اآلبار حفر أو الهيروليكي التكسير سيناريو تنفيذ باتجاه الدفع إلى المكمن، لهذا إجراؤها إجمالي من٪ 1 من أقل إلى اإلنتاج في السعدي مكمن مساهمة تقليل إلى الضعيفة البتروفيزيائية الخصائص في األصلي النفط إجمالي من٪ 22.5 يشكل السعدي مكمن في األصلي النفط أن من الرغم على الحقل إنتاج بعض يف ويصل مكلف أيًضا هو الهيدروليكي والتكسير مرتفعة، األفقية اآلبار حفر تكلفة تعتبر. الحلفاية حقل لجعل ةواالقتصادي التقنية المقارنة الدراسة هذه إجراء تم لذلك،. البئر تكلفة إجمالي من٪ 100 إلى الحاالت متت التي اآلبار أداء يكون المقارنة، أجل من. للنفط استرداد أقصى وتحقيق اقتصادي بمعدل تتدفق اآلبار رالتطوي من لمزيد فيها النظر ويجب األفقية، اآلبار من عام بشكل أفضل الهيدروليكي بالتشقيق معالجتها .والربحية التشغيلية المزايا بين التوازن على والحفاظ السعدي لتكوين .السعدي مكمن النفط؛ استخالص ،اآلبار إنعاش األفقية؛ اآلبار ،الهيدروليكي التشقيق الكلمات الدالة: iraqi journal of chemical and petroleum engineering vol.17 no.1 (march 2016) 1319 issn: 1997-4884 load effect on wall attachment fluidics amplifier performance ali abdalmohsin al-asadi university of baghdad abstract an experimental work has been conducted on wall attachment fluidics amplifiers, one of them to study the effect of output pressure or load on the amplifier performance. the output load has been simulated as a piston connected to the device output and the piston can be loaded accordingly. the results shows that the output volume flow rate increases as the supply pressure increases under different load and the output pressure remains constant as the supply pressure increases under constant load. key words: wall attachment, amplifier performance. introduction for many years engineers have used fluids for transmitting force and energy in mechanical systems. for example, the flexibility and great power offered by hydraulic actuators and motors make them attractive for use in many control systems, even when the systems are essentially electrical or electronic. the predominance of electronic techniques in computations and in control systems may give the impression that such systems can function only electronically. in fact babbage’s calculating ‘engine’ which was perhaps the earliest digital computers, with essential conceptual features of present day machines, was purely mechanical [1], and various simple, completely pneumatic control systems, such as automatic pressure control, have been in commercial use for many years. it is only comparatively recently, however, that techniques have been developed for using fluid as a medium for computation and for carrying significant information in control systems. hydraulic and pneumatic circuits which use valves have been developed for many automatic processes for examples those requiring a controlled sequence of events. the conventional valves used in such circuits have mechanical moving parts and may be classed as static device. the term arises because forces are developed by the static pressure of the fluid, power being expended only intermittently when the fluid is in motion. a new class of fluid circuit element has now been added which may be referred to as dynamic. this elements called fluidic element, one of them is the wall attachment amplifier. in dynamic elements the kinetic energy of the flowing fluid is all-important and in them power is expended continuously, (1). an important aspect iraqi journal of chemical and petroleum engineering university of baghdad college of engineering load effect on wall attachment fluidics amplifier performance 14 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net of such elements is that, they need not depend on moving parts for their operation, another advantage can be claimed for fluidics elements, simplicity loading to high reliability to operate in extreme conditions of temperature, resistance to shock and vibration, safe operation in explosive atmospheres, freedom from interference from radiation, and so on. additionally, the cost of the elements is potentially low. all these feature makes them attractive to use in control system than the others. thee wall attachment principle when a turbulent of fluid emerges from a nozzle, as shown in fig (1-a), it continues to move downstream and is not deflected in one direction or the other. it is found that the turbulent motion of the jet entrains particles from the surrounding fluid causing it spread out as it moves downstream. if the entertainment flow on one side of the jet is reduced due, say the existence of an adjacent wall, the pressure on that side of the jet is reduced due to the differential entertainment, causing the jet to be drawn toward the lowpressure region. if the wall is positioned correctly, as in fig (1-b), the jet is deflected until it touches the wall. between the jet and the wall is low-pressure vortex bubble known as the separation bubble or reattachment bubble. stable condition occur in the bubble when the amount of fluid entertained into the bubble from the jet, at the point at which the jet attaches to the wall, is equal to the amount of fluid reround to the jet by the vortex flow inside the bubble. two important parameters in the design of any wall attachment device. these are the set back and the wall angle. for wall attachment to take place the set back should be small; a large set back results in the jet detaching from the wall at low values of flow. the wall angle also affects wall attachment since, with very large wall angles, attachment may not be possible, or may only be achieved with difficulty. the effects of wall angle and set back are discussed more fully in experimental work [1]. if an additional source of fluid can be admitted to the separation bubble, by the port shown by the broken lines in fig. (1-b), the steady-state operating conditions can be controlled. the net result of increasing the quantity of entertained fluid on the wall side of the jet, is that the jet attachment point moves further downstream. if the fluid flow through the additional port becomes sufficiently great, the jet can be forced to detach from the wall. this is the most commonly used technique of controlling the jet in wall attachment devices. a good example of this method of control is found in the wall attachment s-r flip-flop type. the simplest form of wall attachment device is the diode, atypical profile being shown in fig(2). when an input signal is applied to port 1, the jet attachment to the curved wall due to its gentle gradient, and the pressure recovery at port 2 is approximately 95 percent of the input pressure. if the signal is applied to port 2, most of the input fluid escapes through the vent opposite of port 2, since the inclination of the wall angle to port 1 is too great to permit wall attachment. when used in this mode the pressure recovery at port 1 is approximately 5 percent of the pressure applied to port 2[2]. literature review the first projects on fluidics in britain were those started at the universities of birmingham and nottingham and at the college of aeronautics at cranfield in 1962, the cranfield project used kearffot type hall valve in a circuit designed by charnley and bidgood (2), while the first work at ali abdalmohsin al-asadi -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 15 birmingham and nottingham was another turbulent reattachment amplifier (3), (4). after that a lot of research has been done on fluidics logic element. madellan mitchell and turabull (5), gave experimental results for a jet attaching to the piston face of hydraulic spool valve at small control ports openings and examined the effect of cavitation on the bubble formation while herman viets (6), working on new nozzle development program was under taken to produce a time. dependent flow at nozzle exit, the oscillatory character of the flow was achieved without the use of moving parts by incorporating a fluidic feed back loop in to the nozzle design. description of apparatus 1construction of wall attachment device wall attachment device is often small in size but in the present work a mid-size one has been designed. the device consists of the following parts, see fig. (3): i. device base the device base is design in a way allowing to fixed all the parts of device on it by using glue and bolts as shown in fig.(4). where the base have (235 mm) length, (165 mm) width and (5 mm) thickness. ii. power jet (main jet) this is essential part of an amplifier have rectangular cross section area (8 mm) width and (16 mm) depth. the supply pressure should be generally maintained constant and steady. when the supply pressure and ambient pressure ratio is less than a bout (2), the jet is sub-sonic [7]. this is usually the situation for most bistable amplifiers. iii. control jets one or two control jets are required to control the direction of the main jet. the control jets generally are located at the exit plane of the power jet, which have rectangle cross sectional area. the width of the control jet can be changed from (2.5 mm) to (5 mm) and have (1 mm) depth. iv. splitter the splitter is very important part of an amplifier. its function to separate the two receiving parts. the splitter is generally wedge shaped. the end of the wedge can be rounding, pointed, and blunt or cusp shaped. a sharp splitter (used in present work) tends to have a higher gain and fast responding but it can cause edge tone type oscillation as shown in fig. (5). v. side walls the side walls are also important parts of wall attachment amplifier type s-r flip flop because depend the attach of the fluid flow on the angle of side wall and setback distance. the shape of side walls are shown in fig.(5). vi. receiving ducts the size and shape of the receiving ducts can influence greatly the power output. where the width of receiving ducts (13 mm) and the depth (16 mm). 2construction of loading system (pneumatic piston) the load system consists of a pneumatic cylinder have inside diameter of (46 mm), outside diameter of (50 mm) and length of (125 mm). there is a piston inside the cylinder connected to a shaft with a diameter of (46 mm) as shown in fig.(6). the shaft of piston connected to plate form for loading. the cylinder have two holes one at the bottom of the cylinder where the output of device connection, while the second hole near the top of the cylinder as shown in fig.(7). the circular which is imposed at the load effect on wall attachment fluidics amplifier performance 16 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net bottom of the cylinder to give uniform distribution of pressure on the piston seal to reduce the leakage between the piston and cylinder as shown in fig.(7). 3compressor a compressor is used to provide the rig with air at pressure in the range [0 1000kpa]. a burdon type pressure gauge is used to read the pressure in cylindrical of compressor. the volume flow rate and pressure that at the rig input are regulated by a suitable valve. 4valves and flexible hose the valves used in this experimental work are of type (gate valve). this type is used because there ability to change the pressure and volume flow rate. flexible hoses are used to join the parts of the rig. results and discussion the experimental work has been done to study the effect of load changing on wall attachment fluidics amplifier performance. in the work the experimental data recorded represent the supply pressure, output pressure and output volume flow rate, the device tested under variable load by using pneumatic piston connected to output of wall attachment amplifier. the relation between the output volume flow rate and the supply pressure for different load are shown in fig.(8). where the relation between the output pressure and supply pressure for different load are shown in fig.(9). from the results it is shown that the output volume flow rate (i.e. the input volume flow rate), increases gradually as the supply pressure increases for different constant load, see fig. (8). in the case of output pressure and supply pressure, see fig.(9). in this case it is shown that the output pressure increases until it reaches a specific value, after that the output pressure remains constant under different constant load, that means the load has no effect on the device function, the effect is only on the time response of the device. fig. 1, (a) an unbounded turbulent jet entrains fluid particles on all sides (b) a side wall causes the jet to deflect towards it ali abdalmohsin al-asadi -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 17 fig. 2, a profile of a wall attachment diode fig. 3, main parts of wall attachment device fig. 4, the base of wall attachment device fig. 5, wall attachment device control unit load effect on wall attachment fluidics amplifier performance 18 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net fig. 6, load system pneumatic piston fig. 7, pneumatic piston fig. 8, the relation between supply pressure and output volume flow rate ali abdalmohsin al-asadi -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 19 fig. 9, the relation between supply pressure and output pressure references 1arther conway, aguide to fluidics, macoonaid, london,1971. 2morris, n.m.,(introduction to fluid logic) mc graw – hill,united kingdom, london, 1973. 3charnley,c.j., and biggood, r.e.(fluid logic units and their potential for machine tool application) september 1964.proc. 5 th int. machine tool design and research conference, university of birmingham pergamon presspp.471-498. 4foster,k.,jones,n.s. and mitcheil, d.g., (improvements to a pure fluid sequence control for machine tool application), september 1965. proc.6 th int. machine tool design and research conference, college of since and technology, manchester, pergamon press.393-403. 5faster, k. and jones, n.s. (a simple logic circuit using fluid jet devices), j. vol.5,pergamon press.pp.35-42. 6macleillan.g.d.s, mitcheil.a.e and turnubull.d.e (flow characteristics sump. on automatic control. inst, mech. engrs. london. 7hermann, viets (flip-flop jet nozzle), aiaa journal, vol.13 no 10, october, 1975, pp.1375-1379. 8j.p.holman (experimental methods for engineers), second edition, mc graw-hill kogakuah ltd, 1971. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.21 no.4 (december 2020) 21 – 32 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: hamza qassim ali, email: hamzaashter@gmail.com, name: ahmed a. mohammed, email: ahmed.abd@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. elimination of congo red dyes from aqueous solution using eichhornia crassipes hamza qassim ali and ahmed a. mohammed environmental engineering department, college of engineering, university of baghdad abstract water hyacinth (eichhornia crassipes) is a free-floating plant, growing plentifully in the tropical water bodies. it is being speculated that the large biomass can be used in wastewater treatment, heavy steel and dye remediation, as a substrate for bioethanol and biogas production, electrical energy generation, industrial uses, human food and antioxidants, medicines, feed, agriculture, and sustainable improvement. in this work, the adsorption of congo red (cr) from aqueous solution onto ec biomass was investigated through a series of batch experiments. the effects of operating parameters such as ph (3-9), dosage (0.1-0.9 g. /100 ml), agitated velocity (100300), size particle (88-353μm), temperature (10-50˚c), initial dye concentration (50-500) mg/l, and sorption–desorption were investigated to assess the efficiency of ec-elimination from aqueous solution. different pre-treatments, alkali, and acid were achieved to increase the adsorption uptake. the optimum conditions for maximum removal of cr from an aqueous solution of 50 mg/l were as follows: ph (6), particle size (88 μm), stirring speed (200 rpm), and dose (0.3 g). the experimental isotherms data were analyzed using langmuir, freundlich, and temkin isotherm equations and the results indicated that the langmuir isotherm showed a better fit for cr adsorption with a higher adsorption uptake of 92.263mg/g, and the kinetic data were fitted well with pseudo-secondorder kinetic model. thermodynamic parameters were calculated from van’t hoff plot, confirming that the adsorption process was spontaneous and endothermic. data show that the adsorption-desorption process lasts for four cycles before losing its efficiency and the recovery efficiency increased up to 76.63%. keywords: anionic dye, adsorption, desorption, eichhornia crassipes, endothermic received on 22/11/2019, accepted on 05/09/2020, published on 30/12/2020 https://doi.org/10.31699/ijcpe.2020.4.3 1introduction organic pollution is the term used when large amounts of organic compounds consist of wastewater. it originates from domestic sewage, city run-off, industrial effluents, and agricultural wastewater. sewage cure plant life and industry which includes meals processing, pulp and paper making, agriculture and aquaculture organic pollution include pesticides, fertilizers, hydrocarbons, phenols, plasticizers, biphenyls, detergents, oils, greases, pharmaceuticals, proteins, carbohydrates and dye [1]. in brief, over 100 000 types of dyes have been used for industrial applications in textile, pulp, and paper, pharmaceuticals, tannery [2]. dye wastewater from textile dyeing and dye manufacturing industries cause serious pollution problems. the dye effluents discharged into water bodies like lakes, rivers, etc. [3]. consequently, the removal of dyes from such wastewaters is an important environmental problem and complete dye removal is needed because dyes are visible even at low concentrations [4]. generally, dyes are classified into three categories: (a) anionic: direct, acid, and reactive dyes; (b) cationic: basic dyes; and (c) nonionic: disperse dyes [5]. congo red is an anionic acidic dye, used in the analysis of amyloidosis and medicine as a biological stain. congo pink acts as an indicator with the aid of changing to redbrown coloration in alkaline medium and to blue color in acidic medium. it is additionally used as a gamma-ray congo red is an anionic acidic dye, used in the analysis of amyloidosis and two as a biological stain in medicine. congo red acts as an indicator by using changing to redbrown color in alkaline medium and to blue color in acidic medium. congo purple was used as a gamma-ray dosimeter because its coloration decays with the intensity of irradiation. the congo red poses enormous poisoning in the direction of and animals human beings. both, short time or extended contacts of the cr with and pores and skin eyes cause sharp irritation. on ingestion, it produces gastrointestinal irritation with vomiting, nausea, and diarrhea. it is carcinogenic and prolongs use of the congo red dye outcomes into tumor formation amongsthumans [6]. congo red one of important dye that found in the wastewater have higher solubility in the water about 1 g/30 ml. in general physical, chemical and biological remedy techniques can be used for the elimination of dyes from water. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:hamzaashter@gmail.com mailto:ahmed.abd@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2020.4.3 h. q. ali and a. a. mohammed / iraqi journal of chemical and petroleum engineering 21,4 (2020) 21 32 22 the individual methods vary in their effectivity to eliminate or degrade the dyes and additionally in the cost required for the remedy of the related volumes of polluted water [7]. dyes can't be easily eliminated through traditional cure due to their complex structure and artificial origin. at present, several methods have been employed for the elimination of dye contaminants from wastewater, which encompass ultrasound irradiation, photocatalytic technology, coagulation-flocculation, oxidation, ozonation, membrane separation, biological remedies [8], adsorption, reverse osmosis, ion-exchange, electrochemical destruction[9,10]. at present, adsorption among the numerous techniques reported for the treatment of dye-containing wastewater is considered as one of the most promising methods due to its simplicity, effectiveness, and low cost [11]. hence, in the latest years interests are increasing in the use of alternative non-classical waste materials [12]. so many researchers have proved the capability of agricultural solid wastes as adsorbents to remove many types of pollutants including dyes [13]. this work aims to study the process of purification wastewater through the removal of selective toxic contaminants using water hyacinth (eichhornia crassipes) because it is available in abundance, inexpensive, easy manipulation, non-polluting, relatively simple recovery of metal contaminant for recycling, and are not a source of secondary waste. 2experimental work 2.1. preparation of biomass and adsorbate water hyacinth (eichhornia crassipes) was collected from tiger river in the aldora district of baghdad. step one collected the water hyacinth from the site thoroughly washed it to take the sludge off and dirt and other unwanted materials by tap water from the surfaces of ec. step two, water hyacinths were separated into stems, leaves, and roots. step three, washed several times with distilled water to make its clean then the biomass were dried in the sun for five days ground into, and then washed several times with distilled water before drying in an oven at 105°c for two hoursto ensure that the sample dried completely. step four, the samples are crushed by the electric grinder. the dried pulverized biomass adsorbent material was sieved through standard sieves to obtain particle sizes between (63-125 𝛍m;125-250 𝛍m; 250-500 𝛍m) and storied in a desiccator at room temperature under dry conditions untilused[14,15,16]. a congo red dye (1.0 g) was dissolved per one liter of distilled water to prepare (1000) mg/l of cr stock solution, and the concentration of cr used to experiment (5,10,15,20,30,40,50,100,200,300,400 and 500 mg/l) were obtain by dilution of the stock solution. . 0.1 m of hydrochloric acid or sodium hydroxide base was added to regulate the solution ph to the desired value. congo red dye was the sodium salt of 3,.3´{[1,1’biiphenyl]-4,4´-diylbis(azo)}bis(4-amino-1-naphthalene sulfonic acid disodium salt) with a formula (c32h22n6na2o6s2), has a molecular weight of 696.66 was obtained from sigmae aldrich with, 99.99% purity and its chemical structure is showin in fig. 1.[17,18]. fig. 1. the chemical formula of congo red 2.2. batch experiments the study of batch experiments was limited to six steps to identify the circumstances for the maximum dye removal efficiency. the influence of ph, dosage of adsorbent, rpm, and particle size, initial concentration with time, and temperature on the removal of cr were also examined using eichhornia crassipes. the effect of ph on the congo red adsorption by ec was investigated at ph range from 3 to 9, dosage (0.1-0.9g/100ml), 50 ppm, 200 rpm. agitation speed effects were investigated by using different agitation speeds (100,150, 200,250, and 300 rpm) with 50 mg/l dye solution and the optimum values of dosage and ph. to investigate whether particle size (88, 176, and 353 μm) affected the removal efficiency of congo red, the experiment was applied using 50 mg/l of congo red solution with the optimum values of dosage, ph, and agitation speed. the variance initial concentration of contaminant (50, 100, 200,300,400, and 500 mg/l) with the optimum values of dosage, ph, particle size, and agitation speed to study the effect of initial concentration on removal efficiency. the impact of temperature on the adsorption of congo red dye was studied within the range of temperatures (10, 20, 30, 40, and 50 °c) and the best condition value of previous tests. the associated thermodynamic parameters were calculated from the results of temperature experiments. the studies of desorption help to explain the mechanism of adsorption and recovery of the adsorbate and adsorbent so that makes the treatment process economical, the adsorption-desorption experiments were carried for (0.05 and 0.1 m naoh) discretely up to four cycles. the time of a single cycle system is composed of adsorption phase (120 min) followed by desorption phase (60 min) and the conditions (ph=6, dosage 0.3g/100 ml; speed, 200 rpm; cr concentration, 50 mg/l; temperature, 25˚c), calculated the uptake removal efficiency and eluting efficiencies of the desorbent ed was from the equations below [19]: h. q. ali and a. a. mohammed / iraqi journal of chemical and petroleum engineering 21,4 (2020) 21 32 23 qe = (𝐶𝑖−𝐶𝑒)𝑉 𝑚 (1) removal efficiency % = (𝐶𝑖 −𝐶𝑒) 𝐶𝑖 *100 (2) where: ci –– initial conc. of cr (mg/l) ce ––conc. of cr at time t (mg/l) m –– mass of the ec (g). e (%) = 𝑚𝑑 𝑚𝑎𝑑 * 100 (3) where: md –– the mass desorbed of cr, mg/l mad ––the total adsorbed quantity of cr (mg/l) 3results and discussion 3.1. ft-ir analysis fourier transform infrared spectroscopy (ftir) was used to examine the difference in the functional group of water hyacinth (eichhornia crassipes) and acid treated adsorbents before and after sorption of congo red. analysis of (ftir) was performed using perkin-elmer ftir, (ftir spectrum rx1) [20]. the functional groups are important in the adsorption process and act on the control of the adsorption mechanism. the study was carried out within the range of wave-number of (400– 4000, cm -1 ) [21]. fig. 2, shows the ftir spectrum of water hyacinth (eichhornia crassipes) biomass before and after sorption of congo red dye. the peak around free water hyacinth (eichhornia crassipes) at 3379.28,2922.18, 1649.13 and 1039.22 cm -1 are due to –oh,–ch, c=o, and c-o stretching vibration respectively[20]. reduce the intensity of acute peaks concluded that congo red has been functionalized by the adsorbent. but the peak around modified water hyacinth ( eichhornia crassipes) at 3383.25, 2910.14, 1651.06, and 1050.41 are due to –oh, -ch, c=o, and alcoholic hydroxyl stretching vibration respectively[22]. fig. 2. before adsorption (free ec) and after adsorption of cr 3.2. effect of ph the removal of pollutants from water and wastewater by adsorption is greatly influenced by the ph of the solution which affects the nature of the surface charge of the adsorbent as-well-as the extent of ionization and speciation of the aqueous adsorbate species and consequently the rate of adsorption [23]. a change of ph affects the adsorptive process during the charge on the surface of the adsorbent, the degree of ionization of the adsorptive molecule, and the extent of dissociation of the functional groups on the active sites of the adsorbent [24, 25]. the main red color of cr was found over the ph range of (6–10), and the solution relatively changed its color from red to dark blue when the ph ranges of (3–5). also, the red color of the solution for ph values more than ten used to be various from its major red color. also, congo red was a little soluble in water when the ph value below 2 [26, 27]. the impact of ph on congo red adsorption was studied at 25 c o with 50 mg/l of congo red solution, 0.3 g/l dose of adsorbent, 180 min of contact time, 200 rpm agitation speed, and 88μm particle size adsorbent, when the ph value has increased the adsorption of the dye on the surface of the adsorbent increased until the ph reaches 6 and then the adsorption decreases with increasing ph as shown in fig. 3. the amplify in the extent of adsorption with increase in ph is due to the neutralization of the charges at the surface of the adsorbents. it can be safely assumed that through increasing the ph of the solution desire of the poor facilities (so3) of the dye for the active websites of the adsorbents increases, which in turn facilitates the adsorption procedure as the ph value of the system rise, the quantity of negatively charged sites increases and the range of positively charged web sites decreases. at higher ph, the highly negatively charged adsorbent floor sites do not choose the adsorption of deprotonated cr due to electro-static repulsion. also, minimize adsorption of cr at alkaline ph is because of the presence of extra [oh -1 ] ions competing with the dye anions for the adsorption sites. similar data have been stated for the adsorption of cr on activated carbon and waste orange peels [28]. therefore, the best ph value should be set to 6, when using nile flower to remove the congo red dye, because the electrical interaction between negative charge of cr and positive charge of positive absorption surface is enhanced [8]. h. q. ali and a. a. mohammed / iraqi journal of chemical and petroleum engineering 21,4 (2020) 21 32 24 fig. 3. effect of ph solution on the removal efficiency (m = 0.3 g / 100 ml, 25˚c, ci = 50 mg / l for cr, speed = 200 rpm, 88 μm, and time = 120 min). 3.3. effect of biomass dosage the dose of water hyacinth (eichornia crassipes) is an important parameter to determine the capacity of the sorbent–sorbate equilibrium in the system for a given the best amount of the adsorbent and predict the cost of adsorbent per unit of dye solution [29]. fig. 4 presents that the percentage removal efficiency of congo red increases from 86% to 93.95% with an increase in the dose from 0.1 to 0.3 g/100ml while increasing adsorbent dosage more than 0.3g/100ml resulted in a decrease in the removal efficiency. the initial increase in the adsorbent dosage is related to an increased in the surface area and the higher number of available adsorption sites so that increases removal efficiency. however, the higher dosage will cause the agglomeration of adsorbent particles that can also lead to a decrease in the surface place and increasing the diffusional path length and therefore so that the unsaturation of adsorption sites can also lead to a drop in dye removal percentage. hence, the adsorption sites remain unsaturated during the process as they are not accessible [30, 31, and 32]. fig. 4. effect of adsorbents dosage on the removal of cr dye (co=50 mg/l, ph=6, agitation speed =200 rpm, d=88µm, time=120 min) 3.4 effect of agitated speed agitation rate carries out an important position in the adsorption technique and affecting the distribution of the solute in bulk media and the formation of the externalboundary layer. increasing shaking speed decreases the thickness of the boundary film surrounding adsorbent particles and constrict the resistance offered by film diffusion, finally effect on the adsorption capacity [33, 34, and 35]. the effect of agitation speed on the adsorption capacity of water hyacinth (eichornia crassipes) was studied by varying the shaking speeds range five value (100, 150, 200, 250, and 300 rpm) using an orbital shaker maintained at 25 c 0 . as shown in fig. 5, were kept constant. the removal efficiency percent of congo red increased from 88.39 to 95.03% as the agitation velocity increased from 100 to 300 rpm. the increase in removal efficiency with the increase of rate is due to the proper distribution of adsorbent throughout the bulk solution [36]. fig. 5. effect of agitation speed on removal of congo red dye by adsorbents (co=50 mg/l, ph=6, dosage= 0.3g/100ml, d=88µm, time=120 min) 3.5. effect of biomass particle size the adsorbent particle size adsorbent plays an important parameter in adsorption. the increase in removal efficiency is because that the smaller adsorbent particles have shortened diffusion paths and increased total surface area, and therefore, the capability to penetrate all internal pore structures of adsorbent is very high[37,38,39]. the process of adsorption was carried out using three different ranges of particle size as fine, medium, and coarse (88, 176, and 353) µm, while other parameters were constant. fig. 6 shows that the percentage removal of congo red decreased from 92.91% to 82.39% as the particle size increased. h. q. ali and a. a. mohammed / iraqi journal of chemical and petroleum engineering 21,4 (2020) 21 32 25 fig. 6. effect of particle size on removal of cr (co=50 mg/l, ph=6, dosage=0.3g/100ml, time=120min, agitation speed=200 rpm) 3.6. effect of initial concentration with time initial congo red concentration is a significant role in the sorption process. the effect of the concentration on the removal of congo red dye was carried out at various initial dye concentration (50, 100, 200, 300, 400, and 500) mg/l shown in fig. 7, while other parameters were constant (contact time 120 min, ph 6, dose 0.3 g / l and temperature 25 c 0 ). the efficiency value decreased from 91.87 to 35.45%, when increasing the initial concentration from 50 to 500 mg/l. the initial dye concentration supplies the needful driving force to outdo the resistance to the mass transfer of congo red between the solid phase and aqueous phase [40]. the lowering of removal efficiency of congo red dye with the increase of its initial concentration can be explained as follows: because the mass of water hyacinth (eichornia crassipes) is constant for all six concentrations, while the congo red molecules must compete for sites onto which they can adsorb and the relative number of function group cites decreases with increasing dye concentration on the surface of the adsorbent. [41]. the higher initial concentration of congo red in solution leads to saturation of the available, sites much earlier which results in a higher congo red content in the solution at equilibrium [42]. on the other side, the increase in initial congo red dye concentration will cause an increase in the uptake of the adsorbent because of the high driving force for mass transfer at a high initial dye concentration [43]. it is shown in fig. 8 that the congo red adsorption capacity of adsorbent increased from 15.49 to 65.76 mg/g when the concentration of dye increased from 50 to 500 mg/ l. the effect of contact time on the percentage removal of the congo red dyes was investigated at initial dye concentration ranging from 50 to 500 mg/l as shown in fig. 9. the contact time is one of the significant parameters for the adsorption operation and the optimization of contact time in the adsorption operation is necessary to improve cost effectiveness [44]. the removal efficiency of congo red onto water hyacinth (eichornia crassipes) by adsorption was rapid in the first 25 min due to the larger surface area of water hyacinth (eichornia crassipes) available, then slowly arrive equilibrium after 40 min and hold constant until 120 min. fig. 7. effect of agitation speed on removal of congo red dye by adsorbents (co=50 mg/l, ph=6, dosage= 0.3g/100ml, d=88µm, time=120 min) fig. 8. effect of initial concentration on adsorption uptake of biosorbent (ph 6, m= 0.3 g, 25˚c, speed= 200 rpm, 88 μm and time=120 min) fig. 9. effect of initial concentration with time on the removal efficiency of cr (ph 6, m= 0.3 g, 25˚c, speed= 200 rpm, 88 μm, and time=120 min) h. q. ali and a. a. mohammed / iraqi journal of chemical and petroleum engineering 21,4 (2020) 21 32 26 3.7. effect of temperature and thermodynamic study it is well known that temperature plays an important role in the adsorption process. the result of this effect of temperature range from 10 c 0 to 50 c 0 on the adsorption efficiency is shown in fig. 10 while other parameters were kept constant. with increasing temperature, the results show that the removal efficiency was increased from 81.71% to 93.24%. fig. 10. effect of temperature on the removal efficiency of cr (ph 6, m= 0.3 g, ci= 50 mg/l, speed= 200 rpm, 88 μm, and time =120 min) the sorption thermodynamics is beneficial to look into whether the method is spontaneous or not and additionally to acquire an insight into the sorption conduct. the values of enthalpy and entropy were achieved from the slope and intercept of ln kc versus 1/t. calculate parameters including the gibbs free energy change of adsorption (δg o ), enthalpy (δh o ), and entropy (δs o ) these parameters and the values describing are calculated according to eqs (4-7) and tabulated in table 1. the values of the change in enthalpy indicated that the adsorption process is physical in nature. also the positive value of δh◦ further confirms the endothermic nature of the adsorption process. the negative value of δg o indicates the feasibility and spontaneity of the adsorption process. the positive value of ∆s° indicates the perfect affinity of cr towards adsorbent and increased randomness at the water hyacinth (eichornia crassipes) solution surface [45]. the parameter s* indicates the measure of the potential of an adsorbate to remain on the adsorbent [46]. the activation energy (ea) indicates the type of adsorption which is mainly physical or chemical, so that the activation energy shown in table 1, has a value corresponding to chemisorption[12]. lnkc = ( ∆𝑆 𝑅 ) ( ∆𝐻 𝑅 𝑇 ) (4) δg o = δh o – δs o t (5) kc = ( 𝐶𝑎𝑑 𝐶𝑒 ) (6) s ٭ = (1 ө) exp – ( 𝐸𝑎 𝑅𝑇 ) (7) where: kc the equilibrium constant, cad the adsorbed concentration of rc on the adsorbent per liter of the solution at equilibrium (mg/l), ce is the equilibrium concentration of rc in the solution (mg/l), δh° change of enthalpy (kj/mole), r the universal gas constant (8.314 j/mole. k), δs° change of entropy (j/k. mole), δg o change of the gibbs free energy of ( kj/mole ), t temperature of the solution (k), θ is surface coverage, s* is sticking probability and ea is the activation energy. table 1. the thermodynamic parameters for the sorption of congo red on eichornia crassipes t (k) δg (kj/mol) δs (j/mol.k) δh (kj/mol) ea (kj/mol) s* 273 -3.544 120 30.283 43.771 1.52e-09 293 -4.744 303 -5.945 313 -7.146 323 -8.346 3.8. desorption the desirable reusability is essentially important for practical application therapy due to the fact it will decrease the overall fee. the congo red adsorbed onto adsorbent was recovered by different concentrations of naoh. from the de-sorption study, it used to be determined that for increasing in molarity of naoh, de-sorption increased and greater than (76.63 %) of cr was once desorbed from ec the usage of (0.1 m) naoh solution. desorption of congo red was increased to 81.63% with an increase in the concentration to (0.1 m) naoh solution. the results show that the biomass can be repeated four times under the same condition. equation (3) was used to calculate the recovery percentage of 0.05 and 0.1m naoh concentration. the strong base inability to completely desorb the congo red is because the portion of sorbate can be complex formation between the congo red molecules and the active sites on ec. fig. 11 shows the results of the desorption process this desorption is found to be a better solution as it decreases the process cost and also the dependency of the process on a continuous supply of the biosorbent. h. q. ali and a. a. mohammed / iraqi journal of chemical and petroleum engineering 21,4 (2020) 21 32 27 fig. 11. regeneration efficiency at various concentration of naoh 3.9. pretreatment of biomass pretreatment of ec was done using naoh and /or hcl to raise its efficiency in the removal of dyes from aqueous solution. the water hyacinth (ec) biomass was modify with (0.05, 0.1, and 0.5) m naoh and (0.05, 0.1, and 0.5) m hcl the results plotted in fig. 12, showed ec treated by hcl has high efficiency compared with that treated by naoh. fig. 12. modification of algae biomass using different concentrations of naoh and hcl to remove dyes from solution (ph 6, m= 0.3 g, ci= 50 mg/l, 88 μm, speed= 200 rpm, and time=120 min) 4biosorption isotherm and kinetics models adsorption isotherms learn about are essential for the description of how molecules or ions of adsorbate interact with adsorbent surface sites and additionally are indispensable in optimizing the use of adsorbent. the correlation of equilibrium data the usage of either a theoretical or empirical equation is essential for the adsorption interpretation and prediction of the extent of adsorption. various theoretical and empirical models were established and studied to characterize the different types of adsorption isotherms. the langmuir, freundlich, and temkin isotherms were among the most frequently used [47, 48]. table 2. models to the kinetics and isotherm reference equation model [19] qe = 𝑞𝑚 𝑏 𝐶𝑒 1+𝑏 𝐶𝑒 langmuir isotherm [18] qe = k ce 1/n freundlich isotherm [19] qe =bt ln kt ce bt = 𝑅 𝑇 𝑏𝑡 temkin isotherm [53] ln (qe-qt) = ln qe – k1 t pseudo-first-order [54] 𝑡 𝑞𝑡 = 1 𝐾2 𝑞𝑒2 + 𝑡 𝑞𝑒 pseudo-second-order [53] qt = kp t 1/2 + c intraparticle diffusion [19] qt = 1 𝛽 ln(αβ) + 1 𝛽 ln(t) elovich model [19] ʃ(qe,calc-qe,meas) 2 sum square error (sse) [19] ʃ (𝑞𝑒,𝑐𝑎𝑙𝑐−𝑞𝑒,𝑚𝑒𝑎𝑠)2 𝑞𝑒,𝑚𝑒𝑎𝑠 nonlinear chi-square test (x2) the freundlich model is to describe heterogeneous surface adsorption and multilayer adsorption beneath different non-ideal conditions. temkin isotherm assumes the heat of adsorption of all molecules in the layer decreases linearly with coverage and uniform distribution of binding energies [49]. the langmuir isotherm is prevalently applied to describe the monolayer adsorption befell on the homogeneous surface of adsorbent [50]. fig. 13. isotherm model for sorption of cr dye on ec biomass the microsoft excel solver software was used to analyze of non-linear isotherm model tabulated in table 2. the results of these models were obtained by drawing by congo red uptake (qe) versus congo red concentration (ce) as showed in fig. 13, and values of the parameters were tabulated in table 3. h. q. ali and a. a. mohammed / iraqi journal of chemical and petroleum engineering 21,4 (2020) 21 32 28 the langmuir adsorption model was found to fit the experimental data sufficiently in corresponding with the non-linear correlation coefficients (r 2 ) and the value decrease of the chi-square test statistic (χ 2 ) and sum square error (sse) was favorable. the value of rl shows that the isotherm is favorable. freundlich's value of adsorption intensity (n >1) suggests that the isotherm sorption is favorable [51]. the pseudo-second-order kinetic is greater fitted for this study which is evident with nearly similar values of experimental and calculated values of qe with the high range degree of correlation r2 from (0.99 1) as shown in table 4. so that the pseudo 2nd order model is assumed the ratelimiting step can also be chemical phenomena [52]. the values of the kinetic models are tabulated table 4. table 3. parameters of isotherms for sorption of congo red type of isotherm parameters values langmuir qmax (mg/g) 92.263 b (l/mg) 0.021 r 2 0.983 rl 0.432 sum square error sse 10.990 x 2 1.394 freundlich kf (mg/g) 3.195 n 1.467 r 2 0.811 sum square error sse 17.713 x 2 4.111 temkin kt (l/mg) 0.383 bt 15.939 bt 155.439 r 2 0.978 sum square error sse 14.187 x 2 1.651 table 4. parameters of kinetic models for the sorption of cr kinetics models parameters 50 ppm 100 ppm 300 ppm 400 ppm 500 ppm experimental qe 15.499 29.059 58.295 61.525 70.435 pseudo first order qe 8.399 15.016 33.151 41.048 50.522 k1 0.048 0.028 0.010 0.0062 0.001 r 2 0.761 0.659 0.863 0.713 0.825 pseudo second order qe 15.760 29.981 58.987 62.026 71.798 k2 0.533 0.453 0.261 0.164 0.064 r 2 1 1 1 0.988 0.979 intra-particle diffusion c 13.463 25.299 51.062 55.041 63.339 kp 0.260 0.609 0.676 0.688 0.765 r 2 0.609 0.722 0.883 0.812 0.751 elovich model α 3.64e+15 1.56e+13 3.86e+12 1.64e+08 2.07e+04 β 2.639 1.166 0.579 0.358 0.171 r 2 0.829 0.884 0.966 0.936 0.925 5conclusions the results show that water hyacinth (eichornia crassipes) biomass could be used as an efficient biosorbent material for the removal of congo red dye from aqueous solution. the maximum value of removal efficiency approximately (93%) at ph 6, 0.3 g /100ml dosage, 200 rpm agitation speed, 88 μm particle size, 50 ppm initial cr concentration, and 25˚c temperature for 120 min. langmuir model fitted well the experimental data compared to freundlich and temkin models. the kinetic study showed that the pseudo-second-order model was very well simulated experimental data. the values of (δg°, δh°, and δs°) for the thermodynamic study indicated that the biosorption of cr was the feasibility, spontaneity and endothermic at the ranges (293-323 k) of temperature. the value of adsorption-desorption process showed that the ec can be used for four cycles with nearly the same efficiency. modify the ec with hcl show the highest removal efficiency compared to naoh in all its concentrations. h. q. ali and a. a. mohammed / iraqi journal of chemical and petroleum engineering 21,4 (2020) 21 32 29 nomenclature ec: eichornia crassipes cr: congo red b: affinity of the binding site, l/ mg, bt & bt: temkin constants c: value of intercept that offers an notion about the boundary layer thickness, mg/g cad: adsorbed concentration, mg/l ce: concentration at equilibrium, mg/l ci: initial concentration, mg/ ea: activation energy, kj/ mole δg o : gibbs free energy, kj/mole δh o : enthalpy change, kj/mole k1: pseudo-first-order rate constant, min -1 k2: pseudo-second-order rate constant, g/mg. min kc: equilibrium constant kf: constant indicative of the relative adsorption capacity of the adsorbent, mg/g kp: intra-particle diffusion rate constant, mg/g min0.5 kt: temkin sorption potential, l/ mg m: mass of adsorbent, g 1/n: constant indicative of the intensity of the adsorption qe: sorbed dyes molecules on the adsorbent, mg/ g qm: the maximum sorption capacity for monolayer coverage, mg/ g qt: cr uptake capacity, mg/g at any time t r: universal gas constant s*: sticking probability δs o : entropy change, j/k. mole t: temperature, k v: volume, l ө: surface coverage references [1] m. n. rashed. "adsorption technique for the removal of organic pollutants from water and wastewater". organic pollutants monitoring, risk and treatment, 2013. [2] n. buvaneswari, and c. kannan. "plant toxic and nontoxic nature of organic dyes through adsorption mechanism on cellulose surface". journal of hazardous materials, 189, 294–300, 2011. [3] o¨. go¨k, a. s. o¨zcan, a. o¨zcan. "adsorption behavior of a textile dye of reactive blue 19 from aqueous solutions onto modified bentonite'. applied surface science, 256, 5439–5443, 2010. [4] x. he, k. b. male, p. n. nesterenko, d. brabazon, b. paull, and j. h.t. luong. "adsorption and desorption of methylene blue on porous carbon monoliths and nanocrystalline cellulose". american chemical society, 5, 8796−8804, 2013. [5] m. foroughi-dahr, h. abolghasemi, m. esmaili, a. shojamoradi, and h. fatoorehchi. "adsorption characteristics of congo red from aqueous solution onto tea waste". chemical engineering communications, 202, 181–193, 2015. [6] a. mittal, v. thakur, j. mittal, and h. vardhan. "process development for the removal of hazardous anionic azo dye congo red from wastewater by using hen feather as potential adsorbent". desalination and water treatment, 1944-3986, 2013. [7] n. rajamohan. "equilibrium studies on sorption of an anionic dye onto acid activated water hyacinth roots". african journal of environmental science and technology, vol. 3 (11), 399-404, 2009. [8] v. s. munagapati, and d. kim. "adsorption of anionic azo dye congo red from aqueous solution by cationic modified orange peel powder". journal of molecular liquids, 220, 540–548, 2016. [9] j. m. salman1, a. r. amrin, f. m. hassan, and s. a. jouda. "removal of congo red dye from aqueous solution by using natural materials". mesopotamia environmental journal, vol.1, 82-89, 2015. [10] a. srinivasan, t. viraraghavan. "decolorization of dye wastewaters by biosorbents: a review". journal of environmental management, 91, 1915-1929, 2010. [11] x. li, z. wang, j. ning, m. gao, w. jiang, z. zhou, and g. li. "preparation and characterization of a novel polyethyleneimine cationmodified persimmon tannin bioadsorbent for anionic dye adsorption". journal of environmental management, 217, 305314, 2018. [12] m. arulkumar, p. sathishkumar, and t. palvannan. "optimization of orange g dye adsorption by activated carbon of thespesia populnea pods using response surface methodology". journal of hazardous materials, 186, 827–834, 2011. [13] m. a. mohd salleh, d. k. mahmoud, w. a. wan abdul karim, a. idris. "cationic and anionic dye adsorption by agricultural solid wastes: a comprehensive review". desalination, 280, 1–13, 2011. [14] w. c. wanyonyi, j. m. onyari, and p. m. shiundu. "adsorption of methylene blue dye from aqueous solutions using eichhornia crassipes". bull environ contam toxicol, 2013. [15] i. wauton, and s. e. ogbeide. "characterization of pyrolytic bio-oil from water hyacinth (eichhornia crassipes) pyrolysis in a fixed bed reactor'. biofuels, 2019. [16] q. li, b. chen, p. lin, j. zhou, j. zhan, q. shen, and x. pan. "adsorption of heavy metal from aqueous solution by dehydrated root powder of long-root eichhornia crassipes". international journal of phytoremediation, 2014. [17] a. mittal, j. mittal, a. malviya, and v.k. gupta. "adsorptive removal of hazardous anionic dye ‘‘congo red” from wastewater using waste materials and recovery by desorption". journal of colloid and interface science, 340, 16–26, 2009. [18] a. h. sulaymon, a. a. mohammed, and t. j. al-musawi. "comparative study of removal of cadmium (ii) and chromium (iii) ions from aqueous solution using low-cost biosorbent". international journal of chemical reactor engineering, vol. 12, pp. 477-486, 2014. https://books.google.iq/books?hl=en&lr=&id=p3wfdwaaqbaj&oi=fnd&pg=pa167&dq=%5b1%5d%09m.+n.+rashed.+%22adsorption+technique+for+the+removal+of+organic+pollutants+from+water+and+wastewater%22.+organic+pollutants+-+monitoring,+risk+and+treatment,+2013.&ots=rs8j02aatm&sig=z74wftrbm5l0mrfm8t43qrtf32s&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=p3wfdwaaqbaj&oi=fnd&pg=pa167&dq=%5b1%5d%09m.+n.+rashed.+%22adsorption+technique+for+the+removal+of+organic+pollutants+from+water+and+wastewater%22.+organic+pollutants+-+monitoring,+risk+and+treatment,+2013.&ots=rs8j02aatm&sig=z74wftrbm5l0mrfm8t43qrtf32s&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=p3wfdwaaqbaj&oi=fnd&pg=pa167&dq=%5b1%5d%09m.+n.+rashed.+%22adsorption+technique+for+the+removal+of+organic+pollutants+from+water+and+wastewater%22.+organic+pollutants+-+monitoring,+risk+and+treatment,+2013.&ots=rs8j02aatm&sig=z74wftrbm5l0mrfm8t43qrtf32s&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=p3wfdwaaqbaj&oi=fnd&pg=pa167&dq=%5b1%5d%09m.+n.+rashed.+%22adsorption+technique+for+the+removal+of+organic+pollutants+from+water+and+wastewater%22.+organic+pollutants+-+monitoring,+risk+and+treatment,+2013.&ots=rs8j02aatm&sig=z74wftrbm5l0mrfm8t43qrtf32s&redir_esc=y#v=onepage&q&f=false https://www.sciencedirect.com/science/article/abs/pii/s0304389411002378 https://www.sciencedirect.com/science/article/abs/pii/s0304389411002378 https://www.sciencedirect.com/science/article/abs/pii/s0304389411002378 https://www.sciencedirect.com/science/article/abs/pii/s0304389411002378 https://www.sciencedirect.com/science/article/abs/pii/s016943320901856x https://www.sciencedirect.com/science/article/abs/pii/s016943320901856x https://www.sciencedirect.com/science/article/abs/pii/s016943320901856x https://www.sciencedirect.com/science/article/abs/pii/s016943320901856x https://pubs.acs.org/doi/abs/10.1021/am403222u https://pubs.acs.org/doi/abs/10.1021/am403222u https://pubs.acs.org/doi/abs/10.1021/am403222u https://pubs.acs.org/doi/abs/10.1021/am403222u https://pubs.acs.org/doi/abs/10.1021/am403222u https://www.tandfonline.com/doi/abs/10.1080/00986445.2013.836633 https://www.tandfonline.com/doi/abs/10.1080/00986445.2013.836633 https://www.tandfonline.com/doi/abs/10.1080/00986445.2013.836633 https://www.tandfonline.com/doi/abs/10.1080/00986445.2013.836633 https://www.tandfonline.com/doi/abs/10.1080/00986445.2013.836633 https://www.tandfonline.com/doi/abs/10.1080/19443994.2013.785030 https://www.tandfonline.com/doi/abs/10.1080/19443994.2013.785030 https://www.tandfonline.com/doi/abs/10.1080/19443994.2013.785030 https://www.tandfonline.com/doi/abs/10.1080/19443994.2013.785030 https://www.tandfonline.com/doi/abs/10.1080/19443994.2013.785030 https://www.ajol.info/index.php/ajest/article/view/56269 https://www.ajol.info/index.php/ajest/article/view/56269 https://www.ajol.info/index.php/ajest/article/view/56269 https://www.ajol.info/index.php/ajest/article/view/56269 https://www.sciencedirect.com/science/article/abs/pii/s0167732216307693 https://www.sciencedirect.com/science/article/abs/pii/s0167732216307693 https://www.sciencedirect.com/science/article/abs/pii/s0167732216307693 https://www.sciencedirect.com/science/article/abs/pii/s0167732216307693 https://www.sciencedirect.com/science/article/abs/pii/s0304389406006716 https://www.sciencedirect.com/science/article/abs/pii/s0304389406006716 https://www.sciencedirect.com/science/article/abs/pii/s0304389406006716 https://www.sciencedirect.com/science/article/abs/pii/s0304389406006716 https://www.sciencedirect.com/science/article/pii/s0301479710001209 https://www.sciencedirect.com/science/article/pii/s0301479710001209 https://www.sciencedirect.com/science/article/pii/s0301479710001209 https://www.sciencedirect.com/science/article/pii/s0301479718303402 https://www.sciencedirect.com/science/article/pii/s0301479718303402 https://www.sciencedirect.com/science/article/pii/s0301479718303402 https://www.sciencedirect.com/science/article/pii/s0301479718303402 https://www.sciencedirect.com/science/article/pii/s0301479718303402 https://www.sciencedirect.com/science/article/pii/s0301479718303402 https://www.sciencedirect.com/science/article/abs/pii/s0304389410014937 https://www.sciencedirect.com/science/article/abs/pii/s0304389410014937 https://www.sciencedirect.com/science/article/abs/pii/s0304389410014937 https://www.sciencedirect.com/science/article/abs/pii/s0304389410014937 https://www.sciencedirect.com/science/article/abs/pii/s0304389410014937 https://www.sciencedirect.com/science/article/abs/pii/s0011916411006333 https://www.sciencedirect.com/science/article/abs/pii/s0011916411006333 https://www.sciencedirect.com/science/article/abs/pii/s0011916411006333 https://www.sciencedirect.com/science/article/abs/pii/s0011916411006333 https://www.sciencedirect.com/science/article/abs/pii/s0011916411006333 https://link.springer.com/article/10.1007/s00128-013-1053-0 https://link.springer.com/article/10.1007/s00128-013-1053-0 https://link.springer.com/article/10.1007/s00128-013-1053-0 https://link.springer.com/article/10.1007/s00128-013-1053-0 https://www.tandfonline.com/doi/abs/10.1080/17597269.2018.1558838 https://www.tandfonline.com/doi/abs/10.1080/17597269.2018.1558838 https://www.tandfonline.com/doi/abs/10.1080/17597269.2018.1558838 https://www.tandfonline.com/doi/abs/10.1080/17597269.2018.1558838 https://www.tandfonline.com/doi/abs/10.1080/15226514.2014.898017 https://www.tandfonline.com/doi/abs/10.1080/15226514.2014.898017 https://www.tandfonline.com/doi/abs/10.1080/15226514.2014.898017 https://www.tandfonline.com/doi/abs/10.1080/15226514.2014.898017 https://www.tandfonline.com/doi/abs/10.1080/15226514.2014.898017 https://www.sciencedirect.com/science/article/abs/pii/s0021979709010881 https://www.sciencedirect.com/science/article/abs/pii/s0021979709010881 https://www.sciencedirect.com/science/article/abs/pii/s0021979709010881 https://www.sciencedirect.com/science/article/abs/pii/s0021979709010881 https://www.sciencedirect.com/science/article/abs/pii/s0021979709010881 https://www.researchgate.net/profile/tariq_al-musawi/publication/265556943_comparative_study_of_removal_of_cadmium_ii_and_chromium_iii_ions_from_aqueous_solution_using_low-cost_biosorbent/links/54ff39510cf2741b69f56866/comparative-study-of-removal-of-cadmium-ii-and-chromium-iii-ions-from-aqueous-solution-using-low-cost-biosorbent.pdf https://www.researchgate.net/profile/tariq_al-musawi/publication/265556943_comparative_study_of_removal_of_cadmium_ii_and_chromium_iii_ions_from_aqueous_solution_using_low-cost_biosorbent/links/54ff39510cf2741b69f56866/comparative-study-of-removal-of-cadmium-ii-and-chromium-iii-ions-from-aqueous-solution-using-low-cost-biosorbent.pdf https://www.researchgate.net/profile/tariq_al-musawi/publication/265556943_comparative_study_of_removal_of_cadmium_ii_and_chromium_iii_ions_from_aqueous_solution_using_low-cost_biosorbent/links/54ff39510cf2741b69f56866/comparative-study-of-removal-of-cadmium-ii-and-chromium-iii-ions-from-aqueous-solution-using-low-cost-biosorbent.pdf https://www.researchgate.net/profile/tariq_al-musawi/publication/265556943_comparative_study_of_removal_of_cadmium_ii_and_chromium_iii_ions_from_aqueous_solution_using_low-cost_biosorbent/links/54ff39510cf2741b69f56866/comparative-study-of-removal-of-cadmium-ii-and-chromium-iii-ions-from-aqueous-solution-using-low-cost-biosorbent.pdf https://www.researchgate.net/profile/tariq_al-musawi/publication/265556943_comparative_study_of_removal_of_cadmium_ii_and_chromium_iii_ions_from_aqueous_solution_using_low-cost_biosorbent/links/54ff39510cf2741b69f56866/comparative-study-of-removal-of-cadmium-ii-and-chromium-iii-ions-from-aqueous-solution-using-low-cost-biosorbent.pdf https://www.researchgate.net/profile/tariq_al-musawi/publication/265556943_comparative_study_of_removal_of_cadmium_ii_and_chromium_iii_ions_from_aqueous_solution_using_low-cost_biosorbent/links/54ff39510cf2741b69f56866/comparative-study-of-removal-of-cadmium-ii-and-chromium-iii-ions-from-aqueous-solution-using-low-cost-biosorbent.pdf h. q. ali and a. a. mohammed / iraqi journal of chemical and petroleum engineering 21,4 (2020) 21 32 30 [19] a. a. najim, and a.a. mohammed. " biosorption of methylene blue from aqueous solution using mixed algae". iraqi journal of chemical and petroleum engineering, vol.19 no.4, 1 – 11, 2018. [20] t. k. roy, and n. k. mondal. "biosorption of congo red from aqueous solution onto burned root of eichhornia crassipes biomass". appl water sci, 2017. [21] m. arulkumar, p. sathishkumar, and t. palvannan. "optimization of orange g dye adsorption by activated carbon of thespesia populnea pods using response surface methodology". journal of hazardous materials, 186, 827–834, 2011. [22] sumanjit, seema, r. k. mahajan, and v. k. gupta. "modification of surface behaviour of eichhornia crassipes using surface active agent: an adsorption study". journal of industrial and engineering chemistry, 2014. [23] a. a. mohammed. "biosorption of lead , cadmium and zinc onto sunflower shell equilibrium, kinetic and thermodynamic studies". iraqi journal of chemical and petroleum engineering, 16, 1, 2015. [24] s.d. khattria, and m.k. singhb. "removal of malachite green from dye wastewater using neem sawdust by adsorption". journal of hazardous materials, 167, 1089–1094, 2009. [25] b.k. nandi, a. goswami, and m. k. purkait. "removal of cationic dyes from aqueous solutions by kaolin: kinetic and equilibrium studies". applied clay science, 42, 583–590, 2009. [26] m. foroughi-dahr, h. abolghasemi, m. esmaili, a. shojamoradi, and h. fatoorehchi. "adsorption characteristics of congo red from aqueous solution onto tea waste". chemical engineering communications, 202:2, 181-193, 2015. [27] v. s.munagapati, and d. kim. "adsorption of anionic azo dye congo red from aqueous solution by cationic modified orange peel powder". journal of molecular liquids, 220, 540–548, 2016. [28] a. mittal, j. mittal, a. malviya, and v.k. gupta. "adsorptive removal of hazardous anionic dye ‘‘congo red” from wastewater using waste materials and recovery by desorption". journal of colloid and interface science, 340, 16–26, 2009. [29] m. t. yagub, t. k. sen, s. afroze, and h.m. ang. "dye and its removal from aqueous solution by adsorption: a review". advances in colloid and interface science, 209, 172–184, 2014. [30] n. p. de moraes, f. n. silva, m. l. c. p. da silva, t. m. b. campos, g. p. thim, and l. a. rodrigues. "methylene blue photodegradation employing hexagonal prismshaped niobium oxide as heterogeneous catalyst: effect of catalyst dosage, dye concentration, and radiation source". materials chemistry and physics, 214, 95-106, 2018. [31] r. araga, s. soni, and c. s. sharma. "fluoride adsorption from aqueous solution using activated carbon obtained from koh-treated jamun (syzygium cumini) seed". journal of environmental chemical engineering, 2017. [32] j. abdi, m. vossoughi, n. m. mahmoodi, and i. alemzadeh. "synthesis of metal-organic framework hybrid nanocomposites based on go and cnt with high adsorption capacity for dye removal". chemical engineering journal, 2017. [33] a. alahabadi, a. hosseini-bandegharaei, g. moussavi, b. amin, a. rastegar, h. karimisani, m. fattahi, and m. miri. "comparing adsorption properties of nh4cl-modified activated carbon towards chlortetracycline antibiotic with those of commercial activated carbon". journal of molecular liquids, 2017. [34] a. kumar, and h. m. jena. "adsorption of cr(vi) from aqueous solution by prepared high surface area activated carbon from fox nutshell by chemical activation with h3po4". journal of environmental chemical engineering, 2017. [35] a. a. oladipo, m. gazi, and s. sabersamandari. "adsorption of anthraquinone dye onto eco-friendly semi-ipn biocomposite hydrogel: equilibrium isotherms, kinetic studies and optimization". journal of the taiwan institute of chemical engineers, 2013. [36] p. kumar, and m.s. chauhan. "adsorption of chromium (vi) from the synthetic aqueous solution using chemically modified dried water hyacinth roots". journal of environmental chemical engineering, 7, 103218, 2019. [37] v. k. gupta, a. mittal, a. malviya, and j. mittal. "adsorption of carmoisine a from wastewater using waste materials—bottom ash and deoiled soya". journal of colloid and interface science, 335, 24–33, 2009. [38] m. c. menkitil, c. o. aniagor, c. m. agu, and v. i. ugonabo. "effective adsorption of crystal violet dye from an aqueous solution using ligninrich isolate from elephant grass". water conservation science and engineering, 3, 33–46, 2018. [39] s. shakoor, and a. nasar. "adsorptive decontamination of synthetic wastewater containing crystal violet dye by employing terminalia arjuna sawdust waste". groundwater for sustainable development, 2018. [40] p. s. kumar, s. ramalingam, c. senthamarai, m. niranjanaa, p. vijayalakshmi, and s. sivanesan. "adsorption of dye from aqueous solution by cashew nut shell: studies on equilibrium isotherm, kinetics and thermodynamics of interactions". desalination, 261, 52–60, 2010. [41] g. moussavi, and r. khosravi. "the removal of cationic dyes from aqueous solutions by adsorption onto pistachio hull waste". chemical engineering research and design, 89, 2182–2189, 2011. https://doi.org/10.31699/ijcpe.2018.4.1 https://doi.org/10.31699/ijcpe.2018.4.1 https://doi.org/10.31699/ijcpe.2018.4.1 https://doi.org/10.31699/ijcpe.2018.4.1 https://doi.org/10.31699/ijcpe.2018.4.1 https://link.springer.com/article/10.1007/s13201-015-0358-z https://link.springer.com/article/10.1007/s13201-015-0358-z https://link.springer.com/article/10.1007/s13201-015-0358-z https://www.sciencedirect.com/science/article/abs/pii/s0304389410014937 https://www.sciencedirect.com/science/article/abs/pii/s0304389410014937 https://www.sciencedirect.com/science/article/abs/pii/s0304389410014937 https://www.sciencedirect.com/science/article/abs/pii/s0304389410014937 https://www.sciencedirect.com/science/article/abs/pii/s0304389410014937 https://www.sciencedirect.com/science/article/abs/pii/s1226086x14001099 https://www.sciencedirect.com/science/article/abs/pii/s1226086x14001099 https://www.sciencedirect.com/science/article/abs/pii/s1226086x14001099 https://www.sciencedirect.com/science/article/abs/pii/s1226086x14001099 https://www.sciencedirect.com/science/article/abs/pii/s1226086x14001099 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/248 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/248 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/248 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/248 https://www.sciencedirect.com/science/article/abs/pii/s030438940900140x https://www.sciencedirect.com/science/article/abs/pii/s030438940900140x https://www.sciencedirect.com/science/article/abs/pii/s030438940900140x https://www.sciencedirect.com/science/article/abs/pii/s030438940900140x https://www.sciencedirect.com/science/article/abs/pii/s0169131708000884 https://www.sciencedirect.com/science/article/abs/pii/s0169131708000884 https://www.sciencedirect.com/science/article/abs/pii/s0169131708000884 https://www.sciencedirect.com/science/article/abs/pii/s0169131708000884 https://www.tandfonline.com/doi/abs/10.1080/00986445.2013.836633 https://www.tandfonline.com/doi/abs/10.1080/00986445.2013.836633 https://www.tandfonline.com/doi/abs/10.1080/00986445.2013.836633 https://www.tandfonline.com/doi/abs/10.1080/00986445.2013.836633 https://www.tandfonline.com/doi/abs/10.1080/00986445.2013.836633 https://www.sciencedirect.com/science/article/abs/pii/s0167732216307693 https://www.sciencedirect.com/science/article/abs/pii/s0167732216307693 https://www.sciencedirect.com/science/article/abs/pii/s0167732216307693 https://www.sciencedirect.com/science/article/abs/pii/s0167732216307693 https://www.sciencedirect.com/science/article/abs/pii/s0021979709010881 https://www.sciencedirect.com/science/article/abs/pii/s0021979709010881 https://www.sciencedirect.com/science/article/abs/pii/s0021979709010881 https://www.sciencedirect.com/science/article/abs/pii/s0021979709010881 https://www.sciencedirect.com/science/article/abs/pii/s0021979709010881 https://www.sciencedirect.com/science/article/abs/pii/s0001868614001389 https://www.sciencedirect.com/science/article/abs/pii/s0001868614001389 https://www.sciencedirect.com/science/article/abs/pii/s0001868614001389 https://www.sciencedirect.com/science/article/abs/pii/s0001868614001389 https://www.sciencedirect.com/science/article/abs/pii/s0254058418303328 https://www.sciencedirect.com/science/article/abs/pii/s0254058418303328 https://www.sciencedirect.com/science/article/abs/pii/s0254058418303328 https://www.sciencedirect.com/science/article/abs/pii/s0254058418303328 https://www.sciencedirect.com/science/article/abs/pii/s0254058418303328 https://www.sciencedirect.com/science/article/abs/pii/s0254058418303328 https://www.sciencedirect.com/science/article/abs/pii/s0254058418303328 https://www.sciencedirect.com/science/article/abs/pii/s2213343717305249 https://www.sciencedirect.com/science/article/abs/pii/s2213343717305249 https://www.sciencedirect.com/science/article/abs/pii/s2213343717305249 https://www.sciencedirect.com/science/article/abs/pii/s2213343717305249 https://www.sciencedirect.com/science/article/abs/pii/s2213343717305249 https://www.sciencedirect.com/science/article/abs/pii/s1385894717310069 https://www.sciencedirect.com/science/article/abs/pii/s1385894717310069 https://www.sciencedirect.com/science/article/abs/pii/s1385894717310069 https://www.sciencedirect.com/science/article/abs/pii/s1385894717310069 https://www.sciencedirect.com/science/article/abs/pii/s1385894717310069 https://www.sciencedirect.com/science/article/abs/pii/s0167732216326873 https://www.sciencedirect.com/science/article/abs/pii/s0167732216326873 https://www.sciencedirect.com/science/article/abs/pii/s0167732216326873 https://www.sciencedirect.com/science/article/abs/pii/s0167732216326873 https://www.sciencedirect.com/science/article/abs/pii/s0167732216326873 https://www.sciencedirect.com/science/article/abs/pii/s0167732216326873 https://www.sciencedirect.com/science/article/abs/pii/s0167732216326873 https://www.sciencedirect.com/science/article/abs/pii/s2213343717301276 https://www.sciencedirect.com/science/article/abs/pii/s2213343717301276 https://www.sciencedirect.com/science/article/abs/pii/s2213343717301276 https://www.sciencedirect.com/science/article/abs/pii/s2213343717301276 https://www.sciencedirect.com/science/article/abs/pii/s2213343717301276 https://www.sciencedirect.com/science/article/abs/pii/s187610701300206x https://www.sciencedirect.com/science/article/abs/pii/s187610701300206x https://www.sciencedirect.com/science/article/abs/pii/s187610701300206x https://www.sciencedirect.com/science/article/abs/pii/s187610701300206x https://www.sciencedirect.com/science/article/abs/pii/s187610701300206x https://www.sciencedirect.com/science/article/abs/pii/s187610701300206x https://www.sciencedirect.com/science/article/abs/pii/s2213343719303410 https://www.sciencedirect.com/science/article/abs/pii/s2213343719303410 https://www.sciencedirect.com/science/article/abs/pii/s2213343719303410 https://www.sciencedirect.com/science/article/abs/pii/s2213343719303410 https://www.sciencedirect.com/science/article/abs/pii/s2213343719303410 https://www.sciencedirect.com/science/article/abs/pii/s0021979709003518 https://www.sciencedirect.com/science/article/abs/pii/s0021979709003518 https://www.sciencedirect.com/science/article/abs/pii/s0021979709003518 https://www.sciencedirect.com/science/article/abs/pii/s0021979709003518 https://www.sciencedirect.com/science/article/abs/pii/s0021979709003518 https://link.springer.com/article/10.1007/s41101-017-0040-4 https://link.springer.com/article/10.1007/s41101-017-0040-4 https://link.springer.com/article/10.1007/s41101-017-0040-4 https://link.springer.com/article/10.1007/s41101-017-0040-4 https://link.springer.com/article/10.1007/s41101-017-0040-4 https://link.springer.com/article/10.1007/s41101-017-0040-4 https://www.sciencedirect.com/science/article/abs/pii/s2352801x17301662 https://www.sciencedirect.com/science/article/abs/pii/s2352801x17301662 https://www.sciencedirect.com/science/article/abs/pii/s2352801x17301662 https://www.sciencedirect.com/science/article/abs/pii/s2352801x17301662 https://www.sciencedirect.com/science/article/abs/pii/s2352801x17301662 https://www.sciencedirect.com/science/article/abs/pii/s0011916410003474 https://www.sciencedirect.com/science/article/abs/pii/s0011916410003474 https://www.sciencedirect.com/science/article/abs/pii/s0011916410003474 https://www.sciencedirect.com/science/article/abs/pii/s0011916410003474 https://www.sciencedirect.com/science/article/abs/pii/s0011916410003474 https://www.sciencedirect.com/science/article/abs/pii/s0011916410003474 https://www.sciencedirect.com/science/article/abs/pii/s0263876211000116 https://www.sciencedirect.com/science/article/abs/pii/s0263876211000116 https://www.sciencedirect.com/science/article/abs/pii/s0263876211000116 https://www.sciencedirect.com/science/article/abs/pii/s0263876211000116 h. q. ali and a. a. mohammed / iraqi journal of chemical and petroleum engineering 21,4 (2020) 21 32 31 [42] r. maurya, t. ghosh, c. paliwal, a. shrivast, k. chokshi, i. pancha, a. ghosh, and s.mishra. "biosorption of methylene blue by de-oiled algal biomass: equilibrium, kinetics and artificial neural network modelling". kinetic study of cationic dye biosorption by de-oiled algal biomass, volume 9, 2014. [43] m. a. m. salleh, d. k. mahmoud, w. a. w. abdul karim, and a. idris. "cationic and anionic dye adsorption by agricultural solid wastes:a comprehensive review". desalination, 280, 1–13, 2011. [44] t. maneerung, j. liew, y. dai, s. kawi, c. chong, and c. wang. "activated carbon derived from carbon residue from biomass gasification and its application for dye adsorption: kinetics, isotherms and thermodynamic studies". bioresource technology, 2015. [45] p. s. kumar, s. ramalingam, c. senthamarai, m. niranjanaa, p. vijayalakshmi, and s. sivanesan. "adsorption of dye from aqueous solution by cashew nut shell: studies on equilibrium isotherm, kinetics and thermodynamics of interactions". desalination, 261, 52–60, 2010. [46] g. moussavi, and r. khosravi. "the removal of cationic dyes from aqueous solutions by adsorption onto pistachio hull waste". chemical engineering research and design, 89, 2182–2189, 2011. [47] t. maneerung, j. liew, y. dai, s. kawi, c. chong, and c. wang. "activated carbon derived from carbon residue from biomass gasification and its application for dye adsorption: kinetics, isotherms and thermodynamic studies". bioresource technology, 2015. [48] f. zhang, b.ma, x. jianga, and y. ji. "dual function magnetic hydroxyapatite nanopowder for removal of malachite green and congo red from aqueous solution". powder technology, 302, 207– 214, 2016. [49] e. s. priya,and p. s. selvan. "water hyacinth (eichhornia crassipes) – an efficient and economic adsorbent for textile effluent treatment – a review". arabian journal of chemistry, 2014. [50] h. demiral, and c. güng. "adsorption of copper(ii) from aqueous solutions on activated carbon prepared from grape bagasse". journal of cleaner production, 124, 103e113, 2016. [51] v. v. gedam1, p. raut, a. chahande, and p. pathak. "kinetic, thermodynamics and equilibrium studies on the removal of congo red dye using activated teak leaf powder". applied water science, 2019. [52] f. zhang, j. lan, y. yang, t. wei, r. tan, w.j. song, adsorption behavior and mechanism of methyl blue on zinc oxide nanoparticles, j. nanopart. res. 15, 1–10, 2013. [53] d.p. li, y.r. zhang, x.x. zhao, b.x. zhao, magnetic nanoparticles coated byaminoguanidine for selective adsorption of acid dyes from aqueous solution, chem. eng. j. 232, 425–433, 2013. [54] n. ertugay, and e. malkoc. "adsorption isotherm, kinetic, and thermodynamic studies for methylene blue from aqueous solution by needles of pinus sylvestris l". pol. j. environ. stud, vol. 23, no. 6, 2014. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0109545 https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0109545 https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0109545 https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0109545 https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0109545 https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0109545 https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0109545 https://www.sciencedirect.com/science/article/abs/pii/s0011916411006333 https://www.sciencedirect.com/science/article/abs/pii/s0011916411006333 https://www.sciencedirect.com/science/article/abs/pii/s0011916411006333 https://www.sciencedirect.com/science/article/abs/pii/s0011916411006333 https://www.sciencedirect.com/science/article/abs/pii/s0011916411006333 https://www.sciencedirect.com/science/article/abs/pii/s0960852415014509 https://www.sciencedirect.com/science/article/abs/pii/s0960852415014509 https://www.sciencedirect.com/science/article/abs/pii/s0960852415014509 https://www.sciencedirect.com/science/article/abs/pii/s0960852415014509 https://www.sciencedirect.com/science/article/abs/pii/s0960852415014509 https://www.sciencedirect.com/science/article/abs/pii/s0960852415014509 https://www.sciencedirect.com/science/article/abs/pii/s0011916410003474 https://www.sciencedirect.com/science/article/abs/pii/s0011916410003474 https://www.sciencedirect.com/science/article/abs/pii/s0011916410003474 https://www.sciencedirect.com/science/article/abs/pii/s0011916410003474 https://www.sciencedirect.com/science/article/abs/pii/s0011916410003474 https://www.sciencedirect.com/science/article/abs/pii/s0011916410003474 https://www.sciencedirect.com/science/article/abs/pii/s0263876211000116 https://www.sciencedirect.com/science/article/abs/pii/s0263876211000116 https://www.sciencedirect.com/science/article/abs/pii/s0263876211000116 https://www.sciencedirect.com/science/article/abs/pii/s0263876211000116 https://www.sciencedirect.com/science/article/abs/pii/s0960852415014509 https://www.sciencedirect.com/science/article/abs/pii/s0960852415014509 https://www.sciencedirect.com/science/article/abs/pii/s0960852415014509 https://www.sciencedirect.com/science/article/abs/pii/s0960852415014509 https://www.sciencedirect.com/science/article/abs/pii/s0960852415014509 https://www.sciencedirect.com/science/article/abs/pii/s0960852415014509 https://www.sciencedirect.com/science/article/abs/pii/s0032591016305253 https://www.sciencedirect.com/science/article/abs/pii/s0032591016305253 https://www.sciencedirect.com/science/article/abs/pii/s0032591016305253 https://www.sciencedirect.com/science/article/abs/pii/s0032591016305253 https://www.sciencedirect.com/science/article/abs/pii/s0032591016305253 https://www.sciencedirect.com/science/article/abs/pii/s0032591016305253 https://www.sciencedirect.com/science/article/pii/s1878535214000562 https://www.sciencedirect.com/science/article/pii/s1878535214000562 https://www.sciencedirect.com/science/article/pii/s1878535214000562 https://www.sciencedirect.com/science/article/pii/s1878535214000562 https://www.sciencedirect.com/science/article/abs/pii/s0959652616002651 https://www.sciencedirect.com/science/article/abs/pii/s0959652616002651 https://www.sciencedirect.com/science/article/abs/pii/s0959652616002651 https://www.sciencedirect.com/science/article/abs/pii/s0959652616002651 https://link.springer.com/article/10.1007/s13201-019-0933-9 https://link.springer.com/article/10.1007/s13201-019-0933-9 https://link.springer.com/article/10.1007/s13201-019-0933-9 https://link.springer.com/article/10.1007/s13201-019-0933-9 https://link.springer.com/article/10.1007/s13201-019-0933-9 https://link.springer.com/article/10.1007/s11051-013-2034-2 https://link.springer.com/article/10.1007/s11051-013-2034-2 https://link.springer.com/article/10.1007/s11051-013-2034-2 https://link.springer.com/article/10.1007/s11051-013-2034-2 https://www.sciencedirect.com/science/article/abs/pii/s1385894713010462 https://www.sciencedirect.com/science/article/abs/pii/s1385894713010462 https://www.sciencedirect.com/science/article/abs/pii/s1385894713010462 https://www.sciencedirect.com/science/article/abs/pii/s1385894713010462 https://www.semanticscholar.org/paper/adsorption-isotherm%2c-kinetic%2c-and-thermodynamic-for-ertugay-malko%c3%a7/66c8316cc5811b8565243573c111f35d3210cfde?p2df https://www.semanticscholar.org/paper/adsorption-isotherm%2c-kinetic%2c-and-thermodynamic-for-ertugay-malko%c3%a7/66c8316cc5811b8565243573c111f35d3210cfde?p2df https://www.semanticscholar.org/paper/adsorption-isotherm%2c-kinetic%2c-and-thermodynamic-for-ertugay-malko%c3%a7/66c8316cc5811b8565243573c111f35d3210cfde?p2df https://www.semanticscholar.org/paper/adsorption-isotherm%2c-kinetic%2c-and-thermodynamic-for-ertugay-malko%c3%a7/66c8316cc5811b8565243573c111f35d3210cfde?p2df https://www.semanticscholar.org/paper/adsorption-isotherm%2c-kinetic%2c-and-thermodynamic-for-ertugay-malko%c3%a7/66c8316cc5811b8565243573c111f35d3210cfde?p2df h. q. ali and a. a. mohammed / iraqi journal of chemical and petroleum engineering 21,4 (2020) 21 32 32 زالة صبغة الكونغو الحمراء من المحلول المائي بأستخدام زهرة النيلأ قاسم علي و احمد عبد محمدحمزة سة البيئيةلهندد/كلية الهندسة/قسم ابغداامعة ج صةالخال ( نبات عائم ينمو بكثافة في المسطحات المائية االستوائية. يتم eichhornia crassipesصفير الماء ) التكهن بأن الكتلة الحيوية يمكن استخدامها في معالجة مياه الصرف الصحي ,المعادن الثقيلة واالصباغ , ركيزة ة, االدوية, النتاج االيثانول والغاز الحيوي, توليد الكهرباء, استخدامات صناعية, الغذاء البشري ومضادات االكسد االعالف, الزراعة والتنمية المستدامة. في هذه الدراسة تم تجربة ازالة صبغة الكنغو الحمراء بأستخدام نبات زهرة (, 3-9النيل) صفير الماء( من خالل سلسلة من التجارب الدفعية. تم دراسة تأثير مدى االس الهيدروجيني ) 88-353مل(, حجم الجيسمات)100غم/ 0.1-0.9) (, كمية المادة المازة100-300سرعة التحريك ) سيليزية(, امتصاص 10-50ملغم/لتر(, درجة الحرارة) 50-500ميكرومتر(, التركيز االولي للصبغة) مختلفة بواسطة وقد تم تجربة معالجاتاالمتصاص لتقييم كفائة ازالة صبغة زهرة لنيل من المحلول المائي. الظروف كانت .لزهرة النيلة الحيوية لمتزاز وكذلك استقرار الكتمن أجل تعزيز قدرة ااال االحماضو وياتالقل حجم ،( 6) الحموضة درجة: يلي كما لتر/ مجم 50 قدره مائي محلول من cr للـ القصوى لإلزالة المثلى تم تحليل بيانات (.جم 0.3) والجرعة( الدقيقة في دورة 200) التحريك سرعة ،( ميكرون 88) الجسيمات temkin. و langmuir ,freundlichااليزوثيرم التجريبية بواسطة استخدام نماذج غم عند /مغلم 92.263على امتصاصية لصبغة الكونغو الحمراء (اكثر مالئمة بأlangmuir)كان نموذج درجة مئوية 30 غم, 0.3كمية المادة المازة ميكرو متر ، 88دورة في الدقيقة ، 200، = 6الرقم الهيدروجيني ( الذي تم pseudo-second order kinetic modelكذلك اظهر النموذج ) لتر كتركيز أولي./ملغم 50و ( اكثر مالئمة وان عملية االمتزاز تحدث بصورة تقائية ون التفاعل ماص van’t hoff plotحسابه من ) دورات قبل أن تفقد كفاءتها وزيادة كفاءة الربعستمر سترجاع تااال -متزازية اااللتظهر النتائج أن عمللحرارة. ٪.76.63االسترداد إلى للحرارة ماص, امتصاص ، امتزاز ، أنيونية صبغةالدالة: كلمت لا available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.23 no.4 (december 2022) 49 – 58 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: jassim m. al said naji, email: 150100@uotechnology.edu.iq, name: ghassan h. abdul-majeed, email: ghassan@uob.edu.iq, name: ali k. alhuraishawy, email: ali19_82@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. comparison of estimation sonic shear wave time using empirical correlations and artificial neural network jassim m. al said najia, ghassan h. abdul-majeedb, and ali k. alhuraishawyc a petroleum engineering department, college of engineering, university of baghdad, baghdad, iraq. b department of scientific affairs, university of baghdad, baghdad, iraq. c reservoir and field development directorate, ministry of oil, baghdad, iraq. abstract wellbore instability and sand production onset modeling are very affected by sonic shear wave time (ssw). in any field, ssw is not available for all wells due to the high cost of measuring. many authors developed empirical correlations using information from selected worldwide fields for ssw prediction. recently, researchers have used different artificial intelligence methods for estimating ssw. three existing empirical correlations of carroll, freund, and brocher are used to estimate ssw in this paper, while a fourth new empirical correlation is established. for comparing with the empirical correlation results, another study's artificial neural network (ann) was used. the same data that was adopted by the ann study was used here where it is comprised of 1922 measured points of ssw and the other nine parameters of gamma ray, compressional sonic, caliper, neutron log, density log, deep resistivity, azimuth angle, inclination angle, and true vertical depth from one iraqi directional well. three existing empirical correlations are based only on compressional sonic wave time (csw) for predicting ssw. in the same way of developing previous correlations, a fourth empirical correlation was developed by using all measured data points of ssw and csw. a comparison demonstrated that utilizing ann was better for ssw predicting with a higher r2 equal to 0.966 and lower other statistical coefficients than utilizing four empirical correlations, where correlations of carroll, freund, brocher, and developed fourth had r2 equal to 0.7826, 0.7636, 0.6764, and 0.8016, respectively, with other statistical parameters that show the new developed correlation best than the other three existing. the use of ann or new developed correlation in future ssw calculations is relevant to decision makers due to a number of limitations and target ssw accuracy. keywords: empirical correlations, artificial neural network, sonic shear wave, wellbore deviation, azimuth and inclination. received on 25/06/2022, accepted on 19/07/2022, published on 30/12/2022 https://doi.org/10.31699/ijcpe.2022.4.7 1introduction generally, sonic logs are classified alongside density logs (dl) and neutron logs (nl) as porosity logs where two types of sonic waves exist: compressional sonic wave time (csw) and sonic shear wave time (ssw) [1]. csw and ssw are measured either by dipole sonic log (dsi) on site or by experiments in the laboratory by utilizing core plug samples [2] but computing ssw from core plug tests is an expensive and time-consuming method, and dsi is not running for all wells [3]. sonic waves with density are key parameters for calculating some elastic rock mechanic properties such as biot's coefficient, poisson ratio, shear modulus, rock compressibility factor, and young modulus [4]. elastic rock mechanic properties are important in geomechanical studies for prediction of wellbore instability and sand production onset [5]. formation lithology and its properties, type of fluids that filled rocks and their properties, reservoir temperature, and hydrostatic pressure of the rock column are all parameters that affect sonic wave velocities or transmitted time. laminated clay and structural shale content are making sonic wave transmitting time increase [6] while decreasing in water saturated rocks rather than dry rocks, where at 10% water saturated, sonic waves have a strong decrease in intensity that means an increase in wave transmitting time [7]. from the sixties of last century till now, many empirical correlations have been developed based on logs and core test data of selected worldwide reservoirs as summarized in table 1 [8-15]. all these empirical correlations in table 1. are developed to calculate ssw in terms of shear sonic velocity (ssv) and compressional sonic velocity (csv) with velocity units of kilometer per second (km/sec), where ssv and csv are reciprocals of ssw and csw respectively. recently, at the beginning of the present century, authors have gone to work on artificial intelligent (ai) methods for estimating ssw because of past simple regression correlations shown in table 1. were for special reservoir cases and did not take into account all effective ssw parameters. rezaee et al. (2007) [16] applied three ai methods: fuzzy logic, neurofuzzy, and artificial neural network (ann) to data from two wells in the carnarvon basin, nw shelf of australia's sandstone reservoir, with a third well used for validation. the http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:150100@uotechnology.edu.iq mailto:ghassan@uob.edu.iq mailto:ali19_82@yahoo.com http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2022.4.7 j. m. al said naji et al. / iraqi journal of chemical and petroleum engineering 23,4 (2022) 49 58 50 datasets used were gamma ray (gr), csv, nl, deep resistivity log (drl), and dl. tabari et al. (2012) [17] utilized the ann method for predicting ssv by using a dataset of gr, nl, dl, and csv of one well, while data from two wells was used for ann validation. hadi and nygaard (2018) [18] used ann for prediction of ssv by utilizing data from the production section in the south of iraq where csv and dl are used as input parameters of the input layer. al ghaithi and prasad (2020) [19] adopted feedforward neural network (fnn) for predicting ssv by using field data from the norwegian north sea where the dataset comprised gr, dl, csw, drl, nl, and measured depth (md). al said naji et al (2022) [20] on their submitted paper to the iraqi geological journal are working on ann for predicting ssw based on one iraqi directional well and 1922 measured points of ssw that were used as the output of the proposed ann, beside nine parameters of csw, gr, nl, dl, drl, caliper (cal), true vertical depth (tvd), azimuth angle (azi), and inclination angle (inc) that utilized as inputs. they obtained the following mathematical model for ssw prediction for any directional well: 𝑆𝑆𝑊 = ∑ 𝑊2𝑗 12 𝑗=1 ( 2 1+𝑒 −2(𝑊1𝑗,1 𝑇𝑉𝐷 + 𝑊1𝑗,2 𝐶𝑆𝑊 + 𝑊1𝑗.3 𝐺𝑅 + 𝑊1𝑗,4 𝐶𝐴𝐿 + 𝑊1𝑗.5 𝑁𝐿 + 𝑊1𝑗,6 𝐷𝑅𝐿 + 𝑊1𝑗,7 𝐷𝐿 + 𝑊1𝑗,8 𝐼𝑁𝐶 + 𝑊1𝑗,9 𝐴𝑍𝐼 + 𝑏1𝑗) − 1) + 𝑏2 (1) where w2j is an output-hidden layers weight, w1ji is an input-hidden layers weights, j is the hidden layer neurons, b1j is a hidden layer biases and b2 represents bias of output layer. the present study is aimed at making a comparison between utilizing three existing empirical correlations of carroll (1969), freund (1992) and brocher (2005) and developing a fourth with the results of constructed ann by al said naji et al. (2022) for ssw estimation. table 1. summary of developed empirical correlation for ssv estimation references year correlation of ssv relation with csv (km/sec) eq. number lithology type pickett 1963 𝑆𝑆𝑉 = 0.526. 𝐶𝑆𝑉 (2) limestone pickett 1963 𝑆𝑆𝑉 = 0.556. 𝐶𝑆𝑉 (3) dolomite carroll 1969 𝑆𝑆𝑉 = 0.75609. 𝐶𝑆𝑉 0.81846 (4) various rock types castsgna, et. al 1985 𝑆𝑆𝑉 = −0.05509. 𝐶𝑆𝑉 2 + 1.0168. 𝐶𝑆𝑉 − 1.305 (5) limestone freund 1992 𝑆𝑆𝑉 = 0.763. 𝐶𝑆𝑉 − 0.603 (6) various rock types eskandari, et.al 2004 𝑆𝑆𝑉 = −0.1236. 𝐶𝑆𝑉 2 + 1.6126. 𝐶𝑆𝑉 − 2.3057 (7) carbonate rocks brocher 2005 𝑆𝑆𝑉 = 0.7858 − 0.1244. 𝐶𝑆𝑉 + 0.7949. 𝐶𝑆𝑉 2 − 0.21238. 𝐶𝑆𝑉 3 + 0.006. 𝐶𝑆𝑉 4 (8) various rock types ameen et al 2009 𝑆𝑆𝑉 = 0.52. 𝐶𝑆𝑉 + 0.25251 (9) carbonate rocks al-kattan 2015 𝑆𝑆𝑉 = 0.699. 𝐶𝑆𝑉 0.969 (10) carbonate rocks  field of study and reservoir description the fauqi oil field is located in the missan governorate in the south of iraq. it is 50 km to the north–east of ammara city and 175 km north of basrah city, as shown in fig. 1. it has two domes with north-west, south-east anticlines in the north and south, respectively, and some of its northern dome stretch is in iran. the field length is approximately 23 km and the width is approximately 7 km. the fauqi oil field has two reservoirs: asmari and mishrif. asmari is an iranian name, and it corresponds to three iraqi names for the reservoir, which are: jeribeeuphrates formation, upper kirkuk formation, and middle-lower kirkuk formation. the jeribe-euphrates formation is the upper part of the asmari reservoir that was deposited during the neogene geological period. it is represented as an a unit with sub divisions of (a1, a2, and a3) and an average thickness of 40 m. it has a lithology that consists mainly of 85% dolomite alternated with moderately thin shale. the upper kirkuk formation is a middle sub-reservoir of the asmari formation, deposited during the paleogene geological period. it is denoted as the b unit with its classifications (b1, b2, b3 and b4) and consists basically of thick shale, alternated with thin sandstone, argillaceous limestone, calcareous shale and limestone. the sandstone portion is gray, poorly consolidated, fine to medium grained, subangular to subrounded, moderately sorted, predominantly quartz, and argillaceous. it has an average interval of 120 m. the middle-lower kirkuk formation is a lower sub-reservoir of the asmari formation. during the paleogene geological epoch, the oligocene series and stage of aquitanian to lower oligocene, this reservoir was deposited. it is represented as c and d units in past studies and c unit in modern studies where they are water submerged zones. its lithology is composed mainly of thick shale and argillaceous siltstone alternated with moderately thick argillaceous limestone and sandstone with an average thickness of 200 m [21, 22]. fig. 1. iraqi fauqi oil field location on iraq map [23] 2materials and methods the same dataset utilized by al said naji et al (2022) [20] is used for the present paper. the selected dataset is from one directional well that penetrated the asmari reservoir in the iraqi fauqi oil field. the data of the j. m. al said naji et al. / iraqi journal of chemical and petroleum engineering 23,4 (2022) 49 58 51 mentioned directional well is comprised of 1922 measured points of ssw, beside nine parameters, csw, gr, nl, dl, drl, cal, tvd, azi, and inc, as illustrated in fig. 2. as mentioned above, al said naji et al. (2022) [20] used these data to construct an ann for ssw prediction while considering the effects of well deviation parameters (inc and azi). eq. 1 resulted as a mathematical model of two loops to predict ssw for directional wells. table 2 summarizes the used dataset of selected directional well. fig. 2. used data of directional well logs track [20] table 2. ranges summary of used dataset parameter minimum maximum mean ssw, (us/ft) 89.05 156.94 112.032 tvd, (m) 2993 3185.1 3089.05 csw, (us/ft) 48.58 114.3 64.09 gr, (gapi) 6.56 132.011 44.94 cal, (in) 8.43 14.698 8.77 nl, (dimensionless) 0.301 44.6 16.097 drl, (ohm.m) 0.311 461.54 7.064 dl, (gm/cc) 2.15 2.94 2.569 inc, (deg) 44.55 48.29 47.19 azi, (deg) 321.14 323.44 322.318 2.1. existing empirical correlations selection of an appropriate ssw prediction correlation for a given field is a very big challenge where any mistake in ssw estimation leads to poor prediction of rock elastic properties, making decisions on investments and losses very difficult [24]. asmari reservoir, as described above, consists of different rock types, so any developed empirical correlation from literature based on one rock type cannot be used to calculate ssw. three empirical correlations suitable for various lithology types were used to calculate ssw based on csw data. these existing empirical correlations are carroll (1969), freund (1992), and brocher (2005), illustrated in table 1. as eq. 4, eq. 6, and eq. 8 respectively. carroll in 1969 developed an empirical correlation for ssv determination by using data obtained from the volcanic region of nevada where 62 dry core samples were collected with the same measured log data from different intervals. this correlation was established for all rock types by studying and testing the effects of lithology kinds and hydrostatical loads on ssv estimation [9]. freund in 1992 established an empirical correlation based on 57, 25 and 5 samples of sandstone, siltstone, and claystone, respectively, for the well penetrated rotliegendes reservoir in germany. samples had porosity ranges of 0.01–0.5 and clay content of 0.01–0.88 while measurements were made at pressure ranges between 10–300 mpa. [11]. brocher (2005) introduced a global empirical correlation for ssv determination. he used ssv and csv datasets from various fields in california: (1) fine-grained holocene deposits in san francisco bay; (2) wells with a depth of more than 410 m at santa clara; (3) miocene sedimentary rocks from the central of california; (4) granodiorite and salinan terrane granites from a pilot hole at park-field; and (5) other logs and core plugs from various fields and previous studies [13]. in this paper, the use of these three global correlations in ssw calculating is based on the mentioned measured data, 1922 points of csw, by using excel 2022 in the following sequence: (1) invert csw to csv; (2) multiply the 304.8 conversion factor to convert units from ft/us to km/sec; (3) use correlations to calculate ssv in units of km/sec; and (4) invert ssv to ssw and use the conversion factor to make it in units of us/ft. 2.2. development of new empirical correlation a new polynomial second order empirical correlation was developed by using the same data of csw and ssw that consisted of 1922 measured points which used by al said naji et al. (2022) [20]. this correlation is established in the same way of developing past empirical correlations mentioned in table 1. where its development was based on the plot in fig. 3 below, which has the following formula with a correlation coefficient (r2) equal to 0.8293: 𝑆𝑆𝑊 = −0.0143. 𝐶𝑆𝑊 2 + 3.1521. 𝐶𝑆𝑊 − 29.73 (11) fig. 3. plot of development polynomial second order empirical correlation j. m. al said naji et al. / iraqi journal of chemical and petroleum engineering 23,4 (2022) 49 58 52 2.3. artificial neural network (ann) the ann, constructed by al said naji et al. (2022) [20] in their submitted paper to the iraqi geological journal, is used in this study to compare with the results of utilizing three existing empirical correlations and a developed fourth. they built ann by a dataset of one directional well from iraqi fauqi oil field with measured 1922 points of ssw and nine parameters of tvd, csw, gr, cal, nl, drl, dl, inc, and azi using matlab r2012b. using multi parameters for ann construction to was based on their effects on ssw values where some of the past literatures [2, 3, 25, 26] explained ssw response against different log measurements of csw, gr, cal, nl, drl, and dl while al said naji et al 2022 [20] on their paper demonstrated the positive impact of hole deviation parameters inc and azi and the negative effect of tvd on ssw as summarized in table 3. table 3. multi logs parameters impact on ssw prediction parameter impact on ssw estimation tvd negative csw positive gr dual cal dual nl positive drl negative dl negative inc positive azi positive measured ssw was used as a neuron of output layer while others nine parameters were entered as input layer neurons. tangent function was adopted as hidden layer activation function as appearing in eq. 13 while linear function showed below in eq. 14 used for activating of output layer [27]. 1922 measured points are classified to three parts 70%, 15%, and 15% for ann three processing sequences of training, validation and testing. constructed ann had optimum structure of (ann 9-12-1) based on obtained maximum r2 and minimum mean square error (mse) as appear in fig. 4 in shape of multiple layer perceptron (mpl) with single hidden layer. mpl is the popular structured of networks for functions regression that consisting from three layers input, hidden and output. any layer contains number of neurons that connected with others of next layers with factor called weight (w) while another factor works on adding freedom degree in neurons connection called bias (bi) [28]. each neuron of layers before hidden layer are combining and modifying by acting of hidden and output layers neurons in term of collection junction by following function [29]: 𝑆𝑗 = ∑ 𝑋𝑖 𝑊1𝑗𝑖 + 𝑏1𝑗 𝑛 𝑖=1 (12) 𝑓(𝑆𝑗 ) = 2 1+𝑒 −2 𝑆𝑗 − 1 (13) 𝑍𝑃 = ∑ 𝑊2𝑗 𝑘 𝑗=1 𝑓(𝑆𝑗 ) + 𝑏2𝑗 (14) where n is the neurons number of input layer, xi is the input vector, w1ji is the weight of connection between xi and j, sj is the summation of input weights and biases, b1j. outputs are resulting from passing of sj though an appropriate activation function, zp represents estimated (ssw) value, w2j is an output hidden layer weight, b2j represents bias of output layer, while k is the neurons of hidden layer. ann mathematical model was obtained in eq. 1 was by combining eq. 12, eq. 13 and eq. 14 with substituting of inputs and output variables to simplify ssw calculations. fig. 4. ann structure for ssw prediction 3results and discussion comparison between empirical correlations and ann results was based on statistical parameters of average percent error (ape), absolute average percent error (aapp), standard deviation (sd), mean square error (mse), and correlation coefficient r-square (r2) as shown in the following equations respectively: 𝐴𝑃𝐸 = 1 𝑛 ∑ ( 𝑍𝑚𝑖−𝑍𝑝𝑖 𝑍𝑚𝑖 ) 𝑛 𝑖=1 (15) 𝐴𝐴𝑃𝐸 = 1 𝑛 ∑ |𝑍𝑚𝑖 − 𝑍𝑝𝑖|𝑛𝑖=1 (16) 𝑆𝐷 = ( ∑ (𝑍𝑝,𝑖−𝑍𝑝𝑎𝑣𝑔) 2𝑛 𝑖=1 𝑛 ) 0.5 (17) 𝑀𝑆𝐸 = 1 𝑛 ∑ (𝑍𝑚,𝑖 − 𝑍𝑃,𝑖 ) 2𝑛 𝑖=1 (18) 𝑅2 = 1 − ∑ (𝑍𝑚,𝑖−𝑍𝑃𝑖) 2𝑛 𝑖=1 ∑ (𝑍𝑚,𝑖−𝑍𝑝𝑎𝑣𝑔) 2𝑛 𝑖=1 (19) where zmi, zpi and zpavg are measured, predicted and averaged predicted ssw. fig. 5 and fig. 6 is explaining the performance of both ann and empirical correlations. as note from first looking on these two figures, ann performance is better than four empirical correlations that j. m. al said naji et al. / iraqi journal of chemical and petroleum engineering 23,4 (2022) 49 58 53 mean applying eq. 1 for any directional well for ssw calculation is better than using eq. 4, eq. 6, eq. 8 and eq. 11. fig. 5. ann performance evaluation [20] fig. 6. empirical correlations performance evaluation statistical coefficients for four empirical correlations and ann methods are summarized in table 4. as can be seen, the ann approach is superior than the rest of the empirical models where it had higher r2 and lower ape, aape, mse, and sd. a new developed empirical correlation eq. 11 is better than other existing correlations of carroll (1969), freund (1992), and brcocher (2005) eq. 4, eq. 6, and eq. 8 respectively. table 4. statistical parameters of ssw prediction methods model ape aape mse sd 2r carroll, 1969 0.29345 5.353119 50.93531 15.27 0.7826 freund, 1992 10.03937 13.77396 239.4537 21.22 0.7636 brocher, 2005 6.0883475 9.436357 228.8576 22.19 0.6764 polynomial second order, 2022 0.16461 4.794007 38.65837 12.52 0.8016 ann, 2022 0.006 2.168 9.62 2.69 0.966 to support the above results in table 4., and reinforce what has been reached in the above sentences, we created the following illustrated plots. these plots: fig. 7 presents a plot of measured and predicted ssw by carroll (1969) on the x-axis with tvd on the y-axis. the statistical parameters in table 4 with this figure demonstrated that the carroll correlation outperformed the freund (1992) and brocher (2005) correlations. fig. 8 and fig. 9 state measured ssw against that predicted by freund and brocher with tvd, respectively. brocher was a bad correlation for ssw prediction of asmari reservoir. fig. 10 is applying measured and predicated ssw by a new developed polynomial second order correlation with tvd. the results show that the new developed correlation is better than the other three utilized empirical correlations, and that is expected where the new correlation was established based on measured data related to the target ssw of the asmari reservoir, while others were developed by adopting data from different worldwide reservoirs that had properties different than asmari. fig. 11 shows the ssw of ann with measured. results obtained from ann are much more accurate than results of other empirical methods according to account as much as possible the high number of influencing parameters on ssw in addition to consider wellbore deviation parameters inc and azi. using the ann mathematical model eq. 1 or the developed empirical correlation eq. 11 is related to decision makers, so using the ann resulted model will obtain high accuracy results of ssw but requires data availability and people with programming software knowledge due to the need to make two loops code for ssw estimation, whereas utilizing a new developed equation is easier than the ann model and only requires csw data but will give low accurate ssw prediction. fig. 7. plot of measured and estimated ssw by carroll correlation with tvd j. m. al said naji et al. / iraqi journal of chemical and petroleum engineering 23,4 (2022) 49 58 54 fig. 8. plot of measured and estimated ssw by freund correlation with tvd fig. 9. plot of measured and estimated ssw by brocher correlation with tvd fig. 10. plot of measured and estimated ssw by polynomial second order correlation with tvd j. m. al said naji et al. / iraqi journal of chemical and petroleum engineering 23,4 (2022) 49 58 55 fig. 11. plot of measured and estimated ssw by ann with tvd to apply eq. 1 to any directional well, use the ann matrix parameters obtained by al said naji et al. (2022) study in table 5. constructed ann was (9-12-1) in that each neuron in the hidden layer had twelve weights connected to it for each parameter in the input layer. also, twelve weights were connected between the hidden layer neurons and the output layer neuron. twelve biases add some degree of freedom to each neuron at the hidden layer, while a single bias supports the output layer neuron. applying eq. 1 using table 5. parameters, you need to write code for two loops to calculate ssw. the lack of sufficient data prevented the validation of established models. we recommend validating the developed models by using data from other fields. table 5. constructed ann matrix [20] w1j, tvd w1j, csw w1j, gr w1j, cal w1j, nl w1j, drl w1j, dl w1j, inc w1j, azi jb1 jw2 b2 1.547 -6.385 3.107 4.66 -0.938 5.056 -4.332 1.003 1.133 3.488 -0.157 0.223 0.603 -0.567 0.591 0.455 0.497 2.959 -0.013 0.598 -0.978 -3.935 0.583 1.117 -1.055 2.383 19.42 -3.598 -8.034 -4.075 1.5398 -7.747 15.158 0.382 3.7 3.088 -2.798 -1.775 3.655 -16.18 -3.027 4.316 -2.073 -19.72 0.109 -0.709 0.2396 -0.84 -1.375 -0.565 9.056 -0.346 -0.348 0.787 7.869 -0.741 -5.465 -9.212 -5.083 7.27 3.058 6.371 -15.55 -11.23 0.752 12.453 0.0763 -2.326 -0.749 0.991 1.715 -1.051 -3.229 -1.42 16.492 -10.83 -4.423 0.584 -19.58 7.553 -7.6296 4.557 1.941 19.58 3.476 0.821 17.756 21.856 -0.133 1.805 -3.608 1.336 1.612 1.311 -6.774 -1.252 -6.347 2.704 -1.796 -0.226 1.808 3.937 -0.914 1.473 -1.629 3.678 -2.646 1.773 -8.731 0.778 0.1651 7.043 0.634 0.949 -1.104 -1.802 -3.921 -1.334 5.821 -8.471 -4.005 0.645 2.589 -0.912 0.643 1.908 -0.162 -1.138 -0.412 3.676 -5.105 -0.39 -1.477 4conclusions this work is presenting comparison between empirical correlations and ann results for ssw estimation. same dataset adopted by al said naji et al 2022 is used in present study and it comprised of 1922 measured points of ssw with other nine parameters tvd, csw, gr, cal, nl, drl, dl, inc and azi. three global existing empirical correlations of carroll 1969, freund 1992, and brocher 2005 used for ssw predicting by utilizing all measured points of csw from dataset. a polynomial second order empirical correlation developed by using all measured points of ssw and csw. ann constructed by al said naji et al 2022 results is used to compare with empirical correlations results. statistical parameters demonstrated that ann was very superior than others empirical correlations where it had higher r2 and lower ape, aape, mse and sd. developed second order empirical correlation was best than other correlations of carroll (1969), freund (1992), and brocher (2005) because the last were established based on worldwide fields data different than used dataset of asmari reservoir. using either ann mathematical model equation or new developed second order empirical equation by any consequent authors will depend on data availability, persons knowledge in programming softwares and target ssw accuracy. acknowledgments the authors are grateful for supporting universities of baghdad, and technology, ministry of oil: petroleum j. m. al said naji et al. / iraqi journal of chemical and petroleum engineering 23,4 (2022) 49 58 56 research develop center and reservoir and development directorate. nomenclature aape absolute average percent error ann artificial neural network ape average percent error azi azimuth angle (dego) b1j input hidden layers biases cal caliper log (in) csv compressional sonic velocity (ft/us) or (km/sec) csw compressional sonic wave time (us/ft) dl density log (gm/cc) drl deep resistivity log (ohm.m) dsi dipole sonic imager tool fnn feedforward neural network gr gamma ray log (gapi) inc inclination angle (dego) j hidden layer neurons md measured depth (length unit) mse mean square error n neurons number of input layer nl neutron log (%) r2 correlation coefficient sd standard deviation sj summation of input weights and biases ssv shear sonic velocity (ft/us) or (km/sec) ssw sonic shear wave time (us/ft) sw water saturation (%) tvd true vertical depth (m) w1ji input – hidden layer neurons connection weights w2j output hidden layer connection weights xi input vector zmi measured shear sonic wave time (us/ft) zp predicted sonic shear wave time (us/ft) zpavg average predicted sonic shear wave time (us/ft) references [1] h. h. alkinani, a. t. al-hameedi, s. dunn-norman, r. e. flori and m. a. al-alwani, "intelligent datadriven analytics to predict shear wave velocity in carbonate formations: comparison between recurrent and conventional neural networks," paper presented at the 53rd us rock mechanics/geomechanics symposium held in new york, ny, usa, 2019. [2] m. asoodeh and p. bagheripour, "prediction of compressional, shear, and stoneley wave velocities from conventional well log data using a committee machine with intelligent systems," vol. 45, rock mechanics and rock engineering, 2012, pp. 45-63. doi 10.1007/s00603-011-0181-2. [3] r. k. abdul majeed and a. a. alhaleem, "estimation of shear wave velocity from wireline logs data for amara oilfield, mishrif formation," vol. 53, no.1a, iraqi geological journal, 2020. https://doi.org/10.46717/igj.53.1a.r3.2020.01.30. [4] r. k. abdul majeed and a. a. alhaleem, "an accurate estimation of shear wave velocity using well logging data for khasib carbonate reservoir amara oil field," vol. 26, no.6, journal of engineering, 2022. [5] r. h. allawi and m. s. al-jawad, "an empirical correlations to predict shear wave velocity at southern iraq oilfield," no. 34 part 1, journal of petroleum research and studies, 2022, pp. 1-14. [6] m. a. kassab and a. weller, "study on p-wave and s-wave velocity in dry and wet sandstones of tushka region, egypt," vol. 24, egyptian journal of petroleum, 2015, pp. 1-11. [7] q. a. abdul-aziz and h. a. abdul-hussein, "development a statistical relationship between compressional wave velocity and petrophysical properties from logs data for jeribe formation asmari reservoir in fauqi oil field," vol. 22, no. 3, iraqi journal of chemical and petroleum engineering, 2022, pp. 1-9. [8] g. r. pickett, "acoustic character logs and their applications in formation evaluation," vol. 15, no. 6, j pet technol, spe-452-pa, 1963, pp. 659-667. [9] r. d. carroll, "the determination of the acoustic parameters of volcanic rocks from compressional velocity measurements," vol. 6, int. j. rock mech, 1969, pp. 557-579. [10] j. p. castagna, m. l. batzle, and r. l. eastwood, "relationships between compressional-wave and shear-wave velocities in clastic silicate rocks," vol. 50, no.4, geophysics, 1985. [11] d. freund, "ultrasonic compressional and shear velocities in dry clastic rocks as a function of porosity, clay content, and confining pressure," vol. 108, geophys. j. inr. 1992. pp. 125-135. [12] h. eskandari, m. r. rezaee and m. mohammadina, "application of multiple regression and artificial neural network techniques to predict shear wave velocity from wireline log data for carbonate reservoir, south-west iran," vol. 42, cseg recorder, 2004, pp. 4048. [13] t. m. brocher, "empirical relations between elastic wave speeds and density in the earth’s crust," vol. 95, no. 6, bulletin of the seismological society of america, 2005, pp. 2081–2092. [14] m. s. ameen, b. g. d. smart, j. m. somerville, s. hammilton and n. a. naji, "predicting rock mechanical properties of carbonates from wireline logs (a case study: arab-d reservoir, ghawar field, saudi arabia)," vol. 26, marine and petroleum geology, 2009, pp. 430–444. [15] w. m. al-kattan, "prediction of shear wave velocity for carbonate rocks," vol. 16, no. 4, iraqi journal of chemical and petroleum engineering. 2015. pp. 4549. https://onepetro.org/armausrms/proceedings-abstract/arma19/all-arma19/arma-2019-0511/124881 https://onepetro.org/armausrms/proceedings-abstract/arma19/all-arma19/arma-2019-0511/124881 https://onepetro.org/armausrms/proceedings-abstract/arma19/all-arma19/arma-2019-0511/124881 https://onepetro.org/armausrms/proceedings-abstract/arma19/all-arma19/arma-2019-0511/124881 https://onepetro.org/armausrms/proceedings-abstract/arma19/all-arma19/arma-2019-0511/124881 https://onepetro.org/armausrms/proceedings-abstract/arma19/all-arma19/arma-2019-0511/124881 https://onepetro.org/armausrms/proceedings-abstract/arma19/all-arma19/arma-2019-0511/124881 https://onepetro.org/armausrms/proceedings-abstract/arma19/all-arma19/arma-2019-0511/124881 https://link.springer.com/article/10.1007/s00603-011-0181-2 https://link.springer.com/article/10.1007/s00603-011-0181-2 https://link.springer.com/article/10.1007/s00603-011-0181-2 https://link.springer.com/article/10.1007/s00603-011-0181-2 https://link.springer.com/article/10.1007/s00603-011-0181-2 https://link.springer.com/article/10.1007/s00603-011-0181-2 https://igj-iraq.org/igj/index.php/igj/article/view/135 https://igj-iraq.org/igj/index.php/igj/article/view/135 https://igj-iraq.org/igj/index.php/igj/article/view/135 https://igj-iraq.org/igj/index.php/igj/article/view/135 https://doi.org/10.46717/igj.53.1a.r3.2020.01.30 https://www.joe.uobaghdad.edu.iq/index.php/main/article/view/j.eng.2020.06.09 https://www.joe.uobaghdad.edu.iq/index.php/main/article/view/j.eng.2020.06.09 https://www.joe.uobaghdad.edu.iq/index.php/main/article/view/j.eng.2020.06.09 https://www.joe.uobaghdad.edu.iq/index.php/main/article/view/j.eng.2020.06.09 https://www.joe.uobaghdad.edu.iq/index.php/main/article/view/j.eng.2020.06.09 https://jprs.gov.iq/index.php/jprs/article/view/586 https://jprs.gov.iq/index.php/jprs/article/view/586 https://jprs.gov.iq/index.php/jprs/article/view/586 https://jprs.gov.iq/index.php/jprs/article/view/586 https://www.sciencedirect.com/science/article/pii/s1110062115000033 https://www.sciencedirect.com/science/article/pii/s1110062115000033 https://www.sciencedirect.com/science/article/pii/s1110062115000033 https://www.sciencedirect.com/science/article/pii/s1110062115000033 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/840 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/840 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/840 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/840 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/840 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/840 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/840 https://onepetro.org/jpt/article/15/06/659/160509/acoustic-character-logs-and-their-applications-in https://onepetro.org/jpt/article/15/06/659/160509/acoustic-character-logs-and-their-applications-in https://onepetro.org/jpt/article/15/06/659/160509/acoustic-character-logs-and-their-applications-in https://www.sciencedirect.com/science/article/abs/pii/0148906269900229 https://www.sciencedirect.com/science/article/abs/pii/0148906269900229 https://www.sciencedirect.com/science/article/abs/pii/0148906269900229 https://www.sciencedirect.com/science/article/abs/pii/0148906269900229 https://library.seg.org/doi/abs/10.1190/1.1441933 https://library.seg.org/doi/abs/10.1190/1.1441933 https://library.seg.org/doi/abs/10.1190/1.1441933 https://library.seg.org/doi/abs/10.1190/1.1441933 https://academic.oup.com/gji/article/108/1/125/660527 https://academic.oup.com/gji/article/108/1/125/660527 https://academic.oup.com/gji/article/108/1/125/660527 https://academic.oup.com/gji/article/108/1/125/660527 https://scholar.google.com/scholar?hl=en&as_sdt=0%2c5&q=application+of+multiple+regression+and+artificial+neural+network+techniques+to+predict+shear+wave+velocity+from+wireline+log+data+for+carbonate+reservoir%2c+south-west+iran%2c%22&btng= https://scholar.google.com/scholar?hl=en&as_sdt=0%2c5&q=application+of+multiple+regression+and+artificial+neural+network+techniques+to+predict+shear+wave+velocity+from+wireline+log+data+for+carbonate+reservoir%2c+south-west+iran%2c%22&btng= https://scholar.google.com/scholar?hl=en&as_sdt=0%2c5&q=application+of+multiple+regression+and+artificial+neural+network+techniques+to+predict+shear+wave+velocity+from+wireline+log+data+for+carbonate+reservoir%2c+south-west+iran%2c%22&btng= https://scholar.google.com/scholar?hl=en&as_sdt=0%2c5&q=application+of+multiple+regression+and+artificial+neural+network+techniques+to+predict+shear+wave+velocity+from+wireline+log+data+for+carbonate+reservoir%2c+south-west+iran%2c%22&btng= https://scholar.google.com/scholar?hl=en&as_sdt=0%2c5&q=application+of+multiple+regression+and+artificial+neural+network+techniques+to+predict+shear+wave+velocity+from+wireline+log+data+for+carbonate+reservoir%2c+south-west+iran%2c%22&btng= https://scholar.google.com/scholar?hl=en&as_sdt=0%2c5&q=application+of+multiple+regression+and+artificial+neural+network+techniques+to+predict+shear+wave+velocity+from+wireline+log+data+for+carbonate+reservoir%2c+south-west+iran%2c%22&btng= https://pubs.geoscienceworld.org/ssa/bssa/article-abstract/95/6/2081/146858/empirical-relations-between-elastic-wavespeeds-and https://pubs.geoscienceworld.org/ssa/bssa/article-abstract/95/6/2081/146858/empirical-relations-between-elastic-wavespeeds-and https://pubs.geoscienceworld.org/ssa/bssa/article-abstract/95/6/2081/146858/empirical-relations-between-elastic-wavespeeds-and https://pubs.geoscienceworld.org/ssa/bssa/article-abstract/95/6/2081/146858/empirical-relations-between-elastic-wavespeeds-and https://www.sciencedirect.com/science/article/abs/pii/s0264817209000269 https://www.sciencedirect.com/science/article/abs/pii/s0264817209000269 https://www.sciencedirect.com/science/article/abs/pii/s0264817209000269 https://www.sciencedirect.com/science/article/abs/pii/s0264817209000269 https://www.sciencedirect.com/science/article/abs/pii/s0264817209000269 https://www.sciencedirect.com/science/article/abs/pii/s0264817209000269 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/32 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/32 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/32 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/32 j. m. al said naji et al. / iraqi journal of chemical and petroleum engineering 23,4 (2022) 49 58 57 [16] m. r. rezaee, a, k. ilkhchi and a. barabadi, "prediction of shear wave velocity from petrophysical data utilizing intelligent systems: an example from a sandstone reservoir of carnarvon basin, australia," vol. 55, journal of petroleum science and engineering, 2007, pp. 201-212. [17] k. tabari, o. tabari and m. tabari, "a fast method for estimating shear wave velocity by using neural network," vol. 5, no. 11, australian journal of basic and applied sciences, 2011. pp. 1429-1434. [18] f. a. hadi and r. nygaard, "shear wave prediction in carbonate reservoirs: can artificial neural network outperform regression analysis," paper presented at the 52nd us rock mechanics / geomechanics symposium held in seattle, washington, usa, 2018. [19] a. al ghaithi and m. prasad, "machine learning with artificial neural networks for shear log predictions in the volve field norwegian north sea," society of exploration geophysicists. seg international exposition and 90th annual meeting, 2020. [20] j. m. al said naji, g. h. abdul-majeed, and a. k. alhuraishawy, " prediction sonic shear wave by artificial neural network," vol.55 (2e), pp.152-164, iraqi geological journal, 2022. [21] q. a. abdul-aziz and h. a. abdul-hussein, "integration of geomechanical and petrophysical properties for estimating rate of penetration in fauqi oil field southern iraqi," doctorate dissertation, university of baghdad, collage of engineering, iraq, 2021. [22] w. i. taher, m. s. al jawad and c. w. v. kirk, "reservoir study for asmari reservoir/fauqi field," master thesis, university of baghdad, collage of engineering, iraq, 2011. [23] j. e. fox and t. s. ahlbrandt, "petroleum geology and total petroleum systems of the widyan basin and interior platform of saudi arabia and iraq. u.s," geological survey bulletin, 2002. [24] z. tariq, s. elkatatny, m. mahmoud and a. abdulraheem, "a new artificial intelligence based empirical correlation to predict sonic travel time," paper presented at the international petroleum technology conference, iptc-19005-ms, 2016. [25] s. maleki, a. moradzadeh,r. g. riabi, r. gholami and f. sadeghzadeh, "prediction of shear wave velocity using empirical correlations and artificial intelligence methods," vol. 3, nriag journal of astronomy and geophysics, 2014, pp. 70-81. [26] h. akhundi, m. ghafoori and g. r. lashkaripour, "prediction of shear wave velocity using artificial neural network technique, multiple regression and petrophysical data: a case study in asmari reservoir (sw iran)," vol. 4, open journal of geology, 2014, pp. 303-313. [27] e. jorjani, c. s. chehreh and s. h. mesroghli, "application of artificial neural networks to predict chemical desulfurization of tabas coal," vol. 87, fuel, 2008, pp. 2727–3273. [28] g. h. abdul-majeed, f.s. kadhim, f. h. almahdawi, y. al-dunainawi, a. arabi and w. k. al-azzawi, "application of artificial neural network to predict slug liquid holdup," vol. 150. international journal of multiphase flow, 2022. [29] m. a. razavi, a. mortazavi and m.mousavi, "dynamic modeling of milk ultrafiltration by artificial neural network," vol. 120, j. membrane. 2003, pp. 47-58. https://www.sciencedirect.com/science/article/abs/pii/s0920410506001720 https://www.sciencedirect.com/science/article/abs/pii/s0920410506001720 https://www.sciencedirect.com/science/article/abs/pii/s0920410506001720 https://www.sciencedirect.com/science/article/abs/pii/s0920410506001720 https://www.sciencedirect.com/science/article/abs/pii/s0920410506001720 https://www.sciencedirect.com/science/article/abs/pii/s0920410506001720 https://onepetro.org/armausrms/proceedings-abstract/arma18/all-arma18/arma-2018-905/122672 https://onepetro.org/armausrms/proceedings-abstract/arma18/all-arma18/arma-2018-905/122672 https://onepetro.org/armausrms/proceedings-abstract/arma18/all-arma18/arma-2018-905/122672 https://onepetro.org/armausrms/proceedings-abstract/arma18/all-arma18/arma-2018-905/122672 https://onepetro.org/armausrms/proceedings-abstract/arma18/all-arma18/arma-2018-905/122672 https://onepetro.org/armausrms/proceedings-abstract/arma18/all-arma18/arma-2018-905/122672 https://library.seg.org/doi/abs/10.1190/segam2020-3427540.1 https://library.seg.org/doi/abs/10.1190/segam2020-3427540.1 https://library.seg.org/doi/abs/10.1190/segam2020-3427540.1 https://library.seg.org/doi/abs/10.1190/segam2020-3427540.1 https://library.seg.org/doi/abs/10.1190/segam2020-3427540.1 https://igj-iraq.org/igj/index.php/igj/article/view/1200 https://igj-iraq.org/igj/index.php/igj/article/view/1200 https://igj-iraq.org/igj/index.php/igj/article/view/1200 https://igj-iraq.org/igj/index.php/igj/article/view/1200 https://pubs.usgs.gov/bul/b2202-e/b2202-e.pdf https://pubs.usgs.gov/bul/b2202-e/b2202-e.pdf https://pubs.usgs.gov/bul/b2202-e/b2202-e.pdf https://pubs.usgs.gov/bul/b2202-e/b2202-e.pdf https://onepetro.org/iptconf/proceedings-abstract/16iptc/1-16iptc/d012s057r001/153966 https://onepetro.org/iptconf/proceedings-abstract/16iptc/1-16iptc/d012s057r001/153966 https://onepetro.org/iptconf/proceedings-abstract/16iptc/1-16iptc/d012s057r001/153966 https://onepetro.org/iptconf/proceedings-abstract/16iptc/1-16iptc/d012s057r001/153966 https://onepetro.org/iptconf/proceedings-abstract/16iptc/1-16iptc/d012s057r001/153966 https://www.tandfonline.com/doi/full/10.1016/j.nrjag.2014.05.001 https://www.tandfonline.com/doi/full/10.1016/j.nrjag.2014.05.001 https://www.tandfonline.com/doi/full/10.1016/j.nrjag.2014.05.001 https://www.tandfonline.com/doi/full/10.1016/j.nrjag.2014.05.001 https://www.tandfonline.com/doi/full/10.1016/j.nrjag.2014.05.001 https://www.scirp.org/html/2-1210209_47965.htm https://www.scirp.org/html/2-1210209_47965.htm https://www.scirp.org/html/2-1210209_47965.htm https://www.scirp.org/html/2-1210209_47965.htm https://www.scirp.org/html/2-1210209_47965.htm https://www.scirp.org/html/2-1210209_47965.htm https://www.sciencedirect.com/science/article/abs/pii/s0016236108000409 https://www.sciencedirect.com/science/article/abs/pii/s0016236108000409 https://www.sciencedirect.com/science/article/abs/pii/s0016236108000409 https://www.sciencedirect.com/science/article/abs/pii/s0016236108000409 https://www.sciencedirect.com/science/article/abs/pii/s0301932222000295 https://www.sciencedirect.com/science/article/abs/pii/s0301932222000295 https://www.sciencedirect.com/science/article/abs/pii/s0301932222000295 https://www.sciencedirect.com/science/article/abs/pii/s0301932222000295 https://www.sciencedirect.com/science/article/abs/pii/s0301932222000295 https://www.sciencedirect.com/science/article/abs/pii/s0376738803002114 https://www.sciencedirect.com/science/article/abs/pii/s0376738803002114 https://www.sciencedirect.com/science/article/abs/pii/s0376738803002114 https://www.sciencedirect.com/science/article/abs/pii/s0376738803002114 j. m. al said naji et al. / iraqi journal of chemical and petroleum engineering 23,4 (2022) 49 58 58 كة مقارنة في تخمين زمن موجة القص الصوتية بأستخدام المعادالت التجريبية والشب العصبية االصطناعية 3 الحريشاوي علي خيون و , 2, غسان حميد عبد المجيد1 جاسم محمد السيد ناجي جامعة بغداد, كلية الهندسة, قسم هندسة النفط, بغداد, العراق. 1 جامعة بغداد, بغداد, العراق. 2 وزارة النفط, دائرة المكامن وتطوير الحقول, بغداد, العراق. 3 الخالصة ر زمن حقل ال يتوفنمذجة ثبوتية البئر والتنبأ بأنتاج الرمل تتأثر جدا بزمن موجة القص الصوتية. في اي ة موجة القص الصوتية لكل اآلبار نسبة لكلف قياسه العالية. العديد من الباحثين طوروا معادالت تجريبي ذكاء بأستخدام بيانات بعض الحقول العالمية لحساب زمن موجة القص الصوتية. مؤخرا استخدم الباحثون طرق ال ق تجريبية موجودة لكل من كارول وفريوند وبرونشر االصطناعي لحساب زمن موجة القص الصوتية. ثالث طر تائج نتم استخدامها لحساب زمن موجة القص الصوتية في هذا البحث, بينما الرابعة تم تطويرها. للمقارنة مع ن ساب زمالمعادالت التجريبية المستخدمة تم استخدام نتائج دراسة استخدمت فيها الشبكة العصبية االصناعية لح ل الصوتية. نفس البيانات المستخدمة في دراسة الشبكة االصطناعية تم اعتمادها هنا حيث تشتمموجة القص نقطة مقاسة من عمليات الجس لزمن موجة القص الصوتية مع قياسات تسعة 1922هذه البيانات على ترون مجسات تشمل مجس اشعة كاما ومجس زمن الموجة الصوتية االنضغاطية ومجس قطر البئر ومجس النيو العمق ومجس الكثافة ومجس المقاومية العميقة باالضافة لقراءات زاوية ميل البئر وزاوية الميل عن الشمال و الشاقولي لبئر اتجاهي عراقي. المعادالت التجريبية الثالث الموجودة تستند في حساب زمن موجة القص ها معادلة التجريبية الرابعة تم تطوير الصوتية على نقاط قياسات ازمان الموجات الصوتية االنضغاطية. ال باستخدام كل النقاط المقاسة الزمان موجات القص واالنضغاط الصوتيتان. المقارنة بين الطرق وضحت ان واقل عوامل 0,966طريقة الشبكة العصبية االصطناعية كانت االفضل بأعلى معامل ترابط مساوي ل ل ن كارو مة االربع حيث ان معامل ترابط المعادالت التجريبية لكل احصائية اخرى بالمقارنة مع الطرق التجريبي على التوالي 0,8016و 0,6764و 0,7636و 0,7826وفريوند وبرونشر والمعادلة المطورة الرابعة كان باالضافة الى بقية المعامالت االحصائية التي اثبتت ان المعادلة التجريبية المطورة افضل من الثالث جة . استخدام طريقة الشبكة االصطناعية او المعادلة التجريبية المطورة مستقبال لحساب زمن مو الموجودات .القص الصوتية متعلق بصانعي القرار نسبة لعدد من المحددات ودقة نتائج موجة القص الصوتية المستهدفة بئر ة ميل الالقص الصوتية, انحراف حفرة البئر, زاويالكلمات الدالة: المعادالت التجريبية, الشبكة العصبية االصطناعية, موجة وزاية االنحراف عن الشمال. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol. 24 no.2 (june 2023) 107 – 112 eissn: 2618-0707, pissn: 1997-4884 *corresponding author: name: fatima h. abbas, email: fatma.abbas1607m@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. the effect of variable parameters on carbon residue of iraqi vacuum gas oil using ultrasound techniques fatima h. abbas a, *, tariq m. naife a, and hind barghash b a chemical engineering department, college of engineering, university of baghdad, baghdad, iraq b german university of technology, sultanate of oman abstract an ultrasonic treatment was applied to the vacuum gas oil at intervals of 5 to 30 minutes, at 70°c. in this work, the improvement of the important properties of iraqi vacuum gas oil, such as carbon residue, was studied with several parameter conditions that affect vacuum efficiency, such as sonication time (5, 10, 15, 20, 25, and 30) min, power amplitude (10–50%). after ultrasonic treatment, the carbon residue of vacuum gas oil was evaluated using a conradson carbon residue meter (astm d189). the experiment revealed that the oil's carbon residue had decreased by 16%. as a consequence of the experiment it was discovered that ultrasonic treatment might reduce the carbon residual and density of oil samples being studied. it also noticed that the carbon residue reduced with increased ultrasonic treatment duration and power. the mechanical mixing and cavitation brought about by ultrasonic processing led to a number of modifications in the gas oil molecules. the properties of a typical molecular structure were altered on a microscale. keywords: vacuum gas oil processing, ultrasonic cavitation, heavy oil, oil upgrading, petroleum, power amplitude. received on 06/08/2022, received in revised form on 20/09/2022, accepted on 21/09/2022, published on 30/06/2023 https://doi.org/10.31699/ijcpe.2023.2.12 1introduction the oil industry is currently facing huge challenges as a result of increased demand for gasoline and diesel fuel, as well as stronger environmental regulations and the commitment to achieve the related sdgs. refiners are now compelled to treat leftover oil as traditional petroleum resources gradually diminish [1]. the usage of leftover oil, however, results in additional severe issues, such as catalyst deactivation caused by coke production. the structural properties of vacuum gas oil must be clarified in order to give the best processing conditions for their efficient conversion. the blend of different chemicals that make up gas oil is exceedingly complex [2]. therefore, ultrasonic treatment is seen to be a successful method of transforming leftover oil to assist secondary processing in oil refineries [3]. additionally, it uses less energy to amplify the effects of physicochemical processing ultrasonic treatment results in the thermal scission of heavy oil bonds and the formation of hydrogen atoms, which are used to upgrade heavy molecules [4]. furthermore, the relationship between carbon residue and volatile hydrocarbons, condensed aromatic hydrocarbons, non-hydrocarbons in oils, and notably asphaltenes and resins, reveals the proclivity for coke generation during residual oil processing. carbon residue, an important control indicator for feedstock, can have an influence on product distribution in catalytic cracking: the greater the carbon residue, the higher the coke deposition and the lower the liquid yields[5]. however , ultrasonic treatment can reduce asphaltene and resin concentrations, lowering carbon residue [6]. this action has the potential to change the resin and asphaltene content, structure, and performance of oil processing, which are mostly composed of compounds with condensed rings and heterocyclic structures in resins and asphaltenes [7] . resins and asphaltene include these chemicals. to some extent, ultrasonic treatment can increase the stability of the colloidal system of asphaltenes [8]. ultrasonic therapy's effects on vacuum gas oil are being studied. ultrasound is a developing technology that can be employed in oil production. at this point in the oil chain, achieving a considerable reduction in viscosity is critical since it will minimize costs and operational challenges in pipeline transportation and refineries [9]. there are encouraging laboratory results, but no industrial application thus far, due in part to scaling issues and since all research is exploratory, none hints to the systematic development of the technology [10]. among developing technologies, ultrasound is utilized to induce the acoustic cavitation phenomena. acoustic cavitations allow for the release of high energy within a liquid, which causes catalytic chemical processes and changes in fluid characteristics [11]. ultrasound is a mechanical wave with pressure oscillation, may flow through solid, liquid, and gaseous media. power ultrasound in particular may cause serious sonic cavitation and transport large specific energy http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:fatma.abbas1607m@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2023.2.12 f. h. abbas et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 107 112 108 density into the medium, leading to high temperatures and pressures as well as mechanical impacts (shock waves, micro-jets, and shear force) [12]. the improvement of cavitation bubbles is shown to be fundamental to these effects. when the medium is subjected to ultrasonic irradiation, a cycle of pressure expansion and compression occurs. when negative pressure overcomes the cohesive force between fluid particles, cavitation bubbles appear as medium nuclei. three different ways for cavitation bubbles to form include: (1) a single bubble, (2) a chain of bubbles, and (3) small bubbles that separate from bigger bubbles [13]. when the acoustic intensity approaches the cavitation threshold, which has a certain value, a phenomenon known as acoustic cavitation can occur. as acoustic cavitation often happens at low frequencies, raising the frequency might result in a higher acoustic cavitation threshold [14]. viscosity, interfacial tension, and vapor pressure are moderately active factors that have a significant impact on the cavitation threshold. the quantity of dissolved gas in the medium also has an impact on the cavitation threshold. the cavitation threshold is significantly lowered as a result of fluid microbubbles' assistance in cavitation bubble generation [15]. the carbon residues of petroleum and petroleum products indicate the sample's proclivity to develop carbonaceous deposits (thermal coke) under the effect of heat. the carbon residue is typically proportional to the crude's asphalt concentration and the amount of recoverable lubricating oil fraction. in most circumstances, the lower the carbon residual, the more valuable the oil. the ramsbottom (rcr) or conradson (ccr) astm test techniques represent this in terms of weight percent carbon residue (d-524 and d-189) [16]. the aim of the research is to improve the quality of vacuum gas oil achieved by ultrasound technology. improvement in the physical and chemical characteristics of vacuum gas oil such as density and carbon residue by using ultrasound technology by evaluate the optimum parameters such as power, ultrasonic time, and temperature in order to improve the properties of vacuum gas oil. 2experimental work 2.1. feedstock vacuum gas oil used in this study was obtained from al-dora refinery. some important properties of the vacuum oil are shown in table 1. 2.2. experimental procedure by ultrasound device in this series of studies, vacuum gas oil was treated with an ultrasonic horn reactor at 70 °c and directly subjected to ultrasonic waves for varied time intervals (5-30) minutes at a frequency of (20) khz and a total given power input of (10-50) %. following ultrasonic radiation, the oil samples were cooled to a temperature of 25 °c. the carbon residue of vacuum oil was tested using a the conradson carbon residue (astm d189) after all programs were completed. and the equipment devices used are as follows: a. sonicator as indicated in fig. 1, the first major instrument used in these studies is a sonicator. it is a powerful ultrasonic wave processor with configurable action and a numerical display of operating parameters. the sonicator has a frequency of more than 20 khz and a maximum amplitude of power ultrasound of (100–1200) watts; temperature range: 30~90 °c. table 2 show that sonicator specifications. materials and sonics, inc. created and manufactured the gadget (vx 1200, newton, united states). table 1. properties of vacuum gas oil properties gas oil density (g/cm3) viscosity at (40) ºc sulfur (wt.%) carbon residue (wt.%) aromatic content (%) api, specific gravity at (60/60 °f( pour point ºc boiling range ºc 0.896 8.4 c.st 4.1 12.5 42.0 30.0 42.5 299-538 fig. 1. experimental setup of the ultrasound reactor system table 2. sonicator specifications technical specifications 1-power rating : 100-1200 watts 2frequency : 20-80 khz 3programmable timer : 10 hours 4adjustable pulse on/off : 1 second to 1 minute 5voltage : 110v,50/60hz adaptable off and on pulse times can be set up from 1 second to 60 seconds. total program has a greatest setting up to 10 hours. different types of probes are available to treat any application. b. magnetic stirrer hot plate magnetics stirrer with sensor for temperature degree measurements and of maximum 1100rpm, manufactured by pce americas inc., usa. f. h. abbas et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 107 112 109 3results and discussions 3.1. the effect of ultrasonic radiation temperature on carbon residue content the effect of ultrasonic radiation temperature on the amount of carbon residue in a vacuum gas oil sample was investigated by using 30% of ultrasonic power and a 20minute treatment time. the carbon residue content in the vacuum residue decreased as the radiation temperature climbed from 30 °c to 70 °c. when the temperature was elevated to 70 °c, the carbon residue tended to level out. the results showed that a radiation temperature of 70 °c was adequate for ultrasonic radiation of vacuum gas oil. increasing the temperature can enhance carbon residue while decreasing the cavitation threshold of vacuum gas oil. a certain temperature is required to obtain the highest cavitation effect. however, if the temperature is excessively high, the steam pressure rises, reducing the cavitation action. as a result, the optimum temperature is 70°c. fig. 2 depicts the percentage variation of carbon residue concentration in vacuum residue with increasing ultrasonic radiation temperature at (30%) of power amplitude. fig. 2. effect of ultrasonic radiation temperature on carbon residue at 20 min and 30% power 3.2. the effect of ultrasonic radiation time on carbon residue carbon residue is an important indicator of carbon deposits from petroleum processing, which is mostly obtained from chemicals found in resins, condensed ring asphalt, and heterogeneous ring structures. the experiment showed that, after ultrasonic processing and increasing time, the changes in resin and asphaltene content, as well as oil structure, will affect the carbon residue content and oil processing performance. as seen in fig. 3 the carbon residue concentration decreased with increasing radiation time. the decrease occurred significantly at the beginning of ultrasound and became stable after 20 min. under experimental conditions, the optimal time for carbon residue reduction was set at 20 min. fig. 3. effect of ultrasonic radiation time on carbon residue content 3.3. the effect of ultrasonic radiation power on carbon residue content the carbon residue reduction effect of ultrasonic waves on oil samples increases gradually and tends to be stable with the increase in ultrasonic power. this is because of the fact that the higher the ultrasonic power, the more energy is transferred to the sample, and the cavitation phenomenon is more intense, which makes the carbon residue reduction effect of vacuum oil more significant. when the ultrasonic power reaches a certain value, the cavitation phenomenon tends to be saturated, making the effect of the ultrasonic wave on reducing the carbon residue of vacuum gas oil stable. fig. 4 depicts the change in carbon residue content after increasing the ultrasonic radiation power to 30% for 20 minutes. the results indicated that as ultrasonic power increased, the amount of carbon residue in the sample decreased significantly. the best power for maximum carbon residue reduction under experimental conditions was determined to be 30% and remained stable after 30 minutes. therefore, 20 minutes of radiation time and 30% of power were determined to be the optimal ultrasonic radiation processing parameters. fig. 4. effect of ultrasonic radiation power on carbon residue content at 20 min f. h. abbas et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 107 112 110 3.4. the influence of ultrasonic on the properties of vacuum gas oil the influence of ultrasonography on vacuum oil properties the experiment was carried out across a range of time intervals (5–30 minutes) at 20 khz and power (1050) to assess the effects of ultrasonic radiation on the characteristics of vacuum gas oil such as (density, carbon residue). the result showed when increase in time and power the carbon residue value of the vacuum gas oil reduces by 16 %, from 12.5% to 10.5%. and the radiation temperature of 70 °c was adequate for ultrasonic radiation of vacuum gas oil and the density of the vacuum gas oil also decreased from 0.8984 to 0.8919 g/cm3. this finding demonstrated the effectiveness of ultrasound in reducing density and carbon residue levels. the properties of vacuum gas oil before and after ultrasound radiation is seen in table 3. table 3. properties of vacuum gas oil before and after ultrasound radiation 4conclusions ultrasound treatment can be used to improve the properties of iraqi vacuum gas oil to reduce carbon residue as a crucial step in decarbonizing local oil industries to contribute in achieving sdg 13, knowing that it has been proven through tests that there is a drop in carbon residue percentage of 16%. through experiments, the results have proven that carbon residue decreases from 12.5 to 10.5 % with an increase in time, and the optimal time has been 20 minutes. therefore, carbon residue also decreased with an increase in power, and the optimal power for greatest carbon residue reduction was estimated to be 50%. the process satisfies the carbon residue reduction of vacuum gas oil at ambient pressure without the use of a costly or toxic catalyst. it is considered a useful method for oil refineries as it's a safe, inexpensive, economical, and successful method that can be used directly without the use of equipment. references [1] s. bezergianni, a. dimitriadis, o. kikhtyanin, and d. kubička, “refinery co-processing of renewable feeds,” prog. energy combust. sci., vol. 68, pp. 29– 64, 2018. https://doi.org/10.1016/j.pecs.2018.04.002 [2] á. ibarra, e. rodríguez, u. sedran, j. m. arandes, and j. bilbao, “synergy in the cracking of a blend of bio-oil and vacuum gasoil under fluid catalytic cracking conditions,” ind. eng. chem. res., vol. 55, no. 7, pp. 1872–1880, 2016. https://doi.org/10.1016/j.fuel.2022.124973 [3] b. avvaru, n. venkateswaran, p. uppara, s. b. iyengar, and s. s. katti, “current knowledge and potential applications of cavitation technologies for the petroleum industry,” ultrason. sonochem., vol. 42, pp. 493–507, 2018. https://doi.org/10.1016/j.ultsonch.2017.12.010 [4] e. struhs et al., “ultrasonic-assisted catalytic transfer hydrogenation for upgrading pyrolysis-oil,” ultrason. sonochem., vol. 73, p. 105502, 2021. https://doi.org/10.1016/j.ultsonch.2021.105502 [5] a. k. coker, petroleum refining design and applications handbook, volume 1. john wiley & sons, 2018. [6] a. n. sawarkar, a. b. pandit, s. d. samant, and j. b. joshi, “use of ultrasound in petroleum residue upgradation,” can. j. chem. eng., vol. 87, no. 3, pp. 329–342, 2009. https://doi.org/10.1016/j.ultsonch.2019.104690 [7] m. r. yakubov, g. r. abilova, s. g. yakubova, and n. a. mironov, “composition and properties of heavy oil resins,” pet. chem., vol. 60, no. 6, pp. 637– 647, 2020. http://doi.org/10.1134/s0965544120060109 [8] mohammed, a.-h. a.-k., & hussain, h. k. (2001). deasphaltening and hydrodesulfurization of basrah vacuum residue. iraqi journal of chemical and petroleum engineering, 2(4), 12–18. https://doi.org/10.31699/ijcpe.2001.4.d.-r [9] d.-r. olaya-escobar, l.-a. quintana-jiménez, e.-e. gonzález-jiménez; erika-sofia olaya-escobar, “ultrasound applied in the reduction of viscosity of heavy crude oil,” revista facultad de ingeniería, vol. 29 (54), e11528, 2020. https://doi.org/10.19053/01211129.v29.n54.2020.115 28 [10] a. r. artino jr, j. s. la rochelle, k. j. dezee, and h. gehlbach, “developing questionnaires for educational research: amee guide no. 87,” med. teach., vol. 36, no. 6, pp. 463–474, 2014. https://doi.org/10.3109/0142159x.2014.889814 [11] b. savun-hekimoğlu, “a review on sonochemistry and its environmental applications,” in acoustics, 2020, vol. 2, no. 4, pp. 766–775. https://doi.org/10.3390/acoustics2040042 [12] x. luo, h. gong, z. he, p. zhang, and l. he, “recent advances in applications of power ultrasound for petroleum industry,” ultrason. sonochem., vol. 70, p. 105337, 2021. https://doi.org/10.1016/j.ultsonch.2020.105337 [13] s. s. rashwan, i. dincer, and a. mohany, “a review on the importance of operating conditions and process parameters in sonic hydrogen production,” int. j. hydrogen energy, vol. 46, no. 56, pp. 28418– 28434, 2021. https://doi.org/10.1016/j.ijhydene.2021.06.086 [14] s. hong and g. son, “numerical modelling of acoustic cavitation threshold in water with noncondensable bubble nuclei,” ultrason. sonochem., vol. 83, p. 105932, 2022. https://doi.org/10.1016/j.ultsonch.2022.105932 item before the ultrasonic radiation after the ultrasonic radiation density (40oc). g/cm3 0.8984 0.8919 carbon residue, % 12.5 10.5 https://doi.org/10.1016/j.pecs.2018.04.002 https://doi.org/10.1016/j.fuel.2022.124973 https://doi.org/10.1016/j.ultsonch.2017.12.010 https://doi.org/10.1016/j.ultsonch.2021.105502 https://books.google.iq/books?hl=en&lr=&id=ogutdwaaqbaj&oi=fnd&pg=pr19&dq=%5b5%5d%09a.+k.+coker,+petroleum+refining+design+and+applications+handbook,+volume+1.+john+wiley+%26+sons,+2018.&ots=scbhatybam&sig=1hvyzhl_zkxmdx87zyosx8chlmk&redir_esc=y#v=onepage&q=%5b5%5d%09a.%20k.%20coker%2c%20petroleum%20refining%20design%20and%20applications%20handbook%2c%20volume%201.%20john%20wiley%20%26%20sons%2c%202018.&f=false https://books.google.iq/books?hl=en&lr=&id=ogutdwaaqbaj&oi=fnd&pg=pr19&dq=%5b5%5d%09a.+k.+coker,+petroleum+refining+design+and+applications+handbook,+volume+1.+john+wiley+%26+sons,+2018.&ots=scbhatybam&sig=1hvyzhl_zkxmdx87zyosx8chlmk&redir_esc=y#v=onepage&q=%5b5%5d%09a.%20k.%20coker%2c%20petroleum%20refining%20design%20and%20applications%20handbook%2c%20volume%201.%20john%20wiley%20%26%20sons%2c%202018.&f=false https://books.google.iq/books?hl=en&lr=&id=ogutdwaaqbaj&oi=fnd&pg=pr19&dq=%5b5%5d%09a.+k.+coker,+petroleum+refining+design+and+applications+handbook,+volume+1.+john+wiley+%26+sons,+2018.&ots=scbhatybam&sig=1hvyzhl_zkxmdx87zyosx8chlmk&redir_esc=y#v=onepage&q=%5b5%5d%09a.%20k.%20coker%2c%20petroleum%20refining%20design%20and%20applications%20handbook%2c%20volume%201.%20john%20wiley%20%26%20sons%2c%202018.&f=false https://doi.org/10.1016/j.ultsonch.2019.104690 http://dx.doi.org/10.1134/s0965544120060109 https://doi.org/10.31699/ijcpe.2001.4.d.-r https://doi.org/10.3109/0142159x.2014.889814 https://doi.org/10.3390/acoustics2040042 https://doi.org/10.1016/j.ultsonch.2020.105337 https://doi.org/10.1016/j.ijhydene.2021.06.086 https://doi.org/10.1016/j.ultsonch.2022.105932 f. h. abbas et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 107 112 111 [15] l. a. yusuf, “optimising acoustic cavitation for industrial application.” university of glasgow, 2022. [16] c. yang et al., “characterization of naphthenic acids in crude oils and refined petroleum products,” fuel, vol. 255, p. 115849, 2019. https://doi.org/10.3390/catal12050495 https://theses.gla.ac.uk/82763/ https://theses.gla.ac.uk/82763/ https://doi.org/10.3390/catal12050495 f. h. abbas et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 107 112 112 لموجات ايات تأثير العوامل المتغيرة على بقايا الكربون لزيت الغاز العراقي باستخدام تقن فوق الصوتية 2 ، و هند برغش1 ، طارق محمد نايف، *1 فاطمه حامد عباس بغداد، العراق، جامعة بغدادقسم الهندسة الكيمياوية، كلية الهندسة، 1 سلطنة عمان، الجامعة االلمانية للتكنولوجيا 2 الخالصة 30إلى 5فرغ على فترات من ٪ على زيت الغاز الم50تم تطبيق معالجة بالموجات فوق الصوتية بنسبة لكربون ا، كشفت التجربة أن بقايا دقيقة 30موجات فوق الصوتية لمدة درجة مئوية. بعد عالج بال 70، عند دقيقة ل ٪. نتيجة للتجربة تم اكتشاف أن المعالجة بالموجات فوق الصوتية قد تقل16في الزيت قد انخفضت بنسبة سين ، تمت دراسة تحكما تقلل الكثافة. في هذا العمل ،الكربون التي يتم دراستهاعينة الزيت المتبقية من مثل لفراغ،متغيرة تؤثر على كفاءة ا ، بعدة عوامل، مثل بقايا الكربون لعراقيالخصائص المهمة لزيت غاز الفراغ ا ، حيث وجدوا أن بقايا الكربون ٪(50-10( دقيقة، سعة الطاقة )30، 25، 20، 15، 10، 5زمن الصوتنة ) ة لمعالجاتقل مع زيادة مدة وقوة المعالجة بالموجات فوق الصوتية. أدى الخلط الميكانيكي والتجويف الناتج عن بالموجات فوق الصوتية إلى عدد من التعديالت في جزيئات زيت الغاز. تم تغيير خصائص التركيب الجزيئي غاز ، تم تقييم بقايا الكربون من زيت اللجة بالموجات فوق الصوتيةالنموذجي على مقياس مجهري. بعد المعا .conradson (astm d189) الفراغي باستخدام مقياس بقايا الكربون لطاقة.ا، سعة ولالزيت، البتر حسين، ت، التجويف بالموجات فوق الصوتية، الزيت الثقيلمعالجة زيت الغاز الفراغي ة:دالالكلمات ال available online at https://ijcpe.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.19 no.2 (june 2018) 27 – 31 issn: 1997-4884 corresponding authors: najwa saber majeed, email: dr.najwa_saber@yahoo.com, duaa mahammed naji, email: duaa_mohammed92@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial-noderivatives 4.0 international license synthesis and characterization of iron oxide nanoparticles by open vessel ageing process najwa saber majeed and duaa mahammed naji chemical engineering department, college of engineering, university of baghdad abstract nano-crystalline iron oxide nanoparticles (magnetite) was synthesized by open vessel ageing process. the iron chloride solution was prepared by mixing deionized water and iron chloride tetrahydrate. the product was characterized by x-ray, surface area and pore volume by brunauer-emmet-teller, atomic force microscope (afm) and fourier transform infrared spectroscopy(ftir) . the results showed that the xrd in compatibility of the prepared iron oxide (magnetite) with the general structure of standard iron oxide, and in fourier transform infrared spectroscopy, it is strong crests in 586 bands, because of the expansion vibration manner related to the metal oxygen absorption band (fe–o bonds in the crystals of iron oxide). the results show that the prepared nano iron oxide is with average crystal size 75.92 nm, surface area was 85.97 m 2 /g and the pore volume was found equal to 0.1566 cm 3 /g. keywords: nanomaterial; magnetite; iron oxide; (characterization; iron (ii) chloride) tetrahydrate. accepted on 12/3/2018 1introduction nano-technology has been considered as one of the most important recent advancements in science and technology. nano-particles are one of the important building blocks in the fabrication and development of nano-materials ‎[1]. as a consequence, the nanoparticle has drawn a huge interest from researchers globally due to specific characteristics such as shape, size, and distribution, which could be utilized in a distinct field of applications. nanoparticles iron oxide has an essential role in many chemical, physical and materials science ‎[2]. among nanoparticles, iron magnetic nanoparticles have gained more interest due to their abundance, rapid reaction, superparamagnetic , high competence , nontoxic, enhanced stability and efficiency in chemical and physical adsorption of organic and inorganic pollutants including heavy metals from polluted waters ‎[3]. these unique properties allow fe3o4-nps to be widely used in different areas of applications, such as catalysis ‎[4], magnetic storage media ‎[5], environmental treatment ‎[6], magnetic resonance imaging (mri)‎[7] , and targeted drug delivery ‎[8]. magnetic properties of nanoparticles magnetic can be fitted by their size distributions and particle sizes. the particle sizes and size distributions of nanoparticles magnetic are successively, affected by the synthesis path. for these points, different synthesis methods have been advanced to make iron oxide nanoparticles in order to obtain desired properties ‎[9],which have been reported in other papers, gas-phase deposition and mechanical techniques (physical methods ) ‎[10] ,green synthesis (biological method) ‎[11], co-precipitation method ‎[12], microwave assisted synthesis ‎[13], (chemical methods). the chemical method is the most common for preparing fe3o4 nanoparticles. chemical preparation methods, relatively less energy were consumed compared with that of physical methods. the size and morphology of the nanoparticles can be controlled by selectively choosing the reaction media, the physical parameters of the reaction, such as precursors, reactant concentration, base (naoh and ammonium hydroxide), temperature, ph . biological method represents an advantageous manufacturing technology with respect to high yield, good, as well as low costs and low energy input, but the fermentation process is rather time-consuming ‎[14]. in other work presents the synthesis of multi shapes of fe3o4 nanoparticles like spherical , plate, and nano flowers by chemical method by solve thermal method assisted by microwave radiation, by using feso4⋅(nh4)2so4⋅6h2o as iron precursor, , ethanol and naoh ‎[15]. this work presents the synthesis and characterization of fe3o4 nanoparticles from raw materials, cheap and available by iron (ii) chloride tetrahydrate and sodium hydroxide by open vessel ageing process. 2experimental work 2.1. materials every component used for the preparation of fe3o4 were analytical grade and used without further purification. iron (ii) chloride tetrahydrate(98%), sodium hydroxide [naoh](98%) were purchased from sigma, germany. n. s. majeed and d. m. naji / iraqi journal of chemical and petroleum engineering91,2 (2018) 27-31 82 2.2. the procedure of fe3o4 synthesis the preparation process of fe3o4 including the following steps: a. 1l of a 30 mm solution of fecl2 was prepared from deionized water and fecl2.4h2o. b. the solution was then titrated with sodium hydroxide solution at a rate about 1ml/min. the solution kept on constant mixing to attain a well-mixed blend. c. then the fe(oh)x was put in the teflon container and heated in a programmable electrical furnace with maximum temperature. d. the particles were heated at constant temperature of 100ºc for 60 min and consequently cooled to room temperature. e. the product obtained was filtered using buckner funnel with the aid of a vacuum pump and washed twice with deionized water and then dried in an electrical oven for 24 hours at 100 °c. fecl2+2naoh fe(oh)2+2nacl 3fe(oh)2 fe3o4+2h2o+h2 fig. 1 shows schematic diagram of preparation procedure of magnetite. on the other hand fig. 1. the schematic diagram of preparation method fig. 2. photographs of a solution in the absence and presence of a magnet fig. 2 the magnetic response of fe3o4 mnps was test by placing a magnet near the glass bottle. the particles were attracted toward the magnet; so, the fe3o4 mnps can be separated under an external magnetic field. 2.3. characterization many characterization techniques were used to measure specification and properties of nanofe3o4. xrd analyses were carried out at room temperature using a shimadzu 6000 (japan) using cukα radiation nickel filter (λ= 1.5418a). ata ere o e ted ithin the 2 range of 2 and 50 ith a 2θ step size of 0.02 and a step time of 0.24s per step (40kv and 30ma). the surface area of prepared catalyst was measured by nitrogen adsorption at liquid nitrogen temperature at -196 c using the bet method, pore volume is a measure the void space in the catalyst. the chemical composition of the prepared fe3o4 was analyzed using xrf technique. conducted the test for a device of the type spectro xeros, germany by weight of sample is 3g in powder state, put in plastic cup 30mm diameter. test conducted in inert atmosphere (helium). atomic force microscope (afm) is a powerful technique for surface investigation by providing material topology in high resolution. the test was performed by device (type angstrom, scanning probe microscope, advanced inc, aa 3000, usa), performed for samples by ethanol dispersion to conducted the surface morphology and the particles size. and ft-ir spectroscopy analysis of fe3o4 was carried out to study the features their structural by the chemical bonds (functional group) between molecules. this test was determined using a shimadzu ftir 8400s (japan) with wave number range (400-4000 cm -1 ). 3results and discussion 3.1. x-ray diffraction (xrd) x-ray diffraction was implemented to check the required pattern of fe3o4 and its crystalline. from fig. 3 x-ray diffraction pattern of the prepared nanofe3o4 is approximately comparable with the standard and table1 comparison of lattice spacing and angle, between prepared nanofe3o4 and standard. fig. 3. xrd pattern of prepared nano fe3o4 n. s. majeed and d. m. naji / iraqi journal of chemical and petroleum engineering91,2 (2018) 27-31 82 table 1. comparison of lattice spacing and angle, between prepared fe3o4 and standard prepared catalyst standard of catalyst angle(2theta)deg d, spacing(å) angle(2theta)deg d, spacing(å) 30.22 2.954 30.094 2.967 35.601 2.519 35.422 2.532 43.246 2.09 43.051 2.099 53.59 1.708 53.390 1.714 57.225 1.608 56.942 1.615 62.873 1.476 62.514 1.484 71.310 1.321 70.923 1.327 3.2. surface area and pore volume the surface area of magnetite range from 4-100m 2 /g .the obtained value of surface area of prepared nanomagnetite =85.97m 2 /g, this value is in agreement with standard ‎[16]. the pore volume for nanomagnetite (fe3o4) was found equal to 0.1566cm 3 /g. 3.3. atomic force microscope (afm) the surface uniformity of the prepared nanofe3o4 was studied using atomic force microscope with 408 pixel density. fig. 4 shows afm on two-dimensional surface profile while fig. 5 shows afm for two dimensional surface profiles. the two dimensional image showed hexagonal structure and three dimensional image of the fe3o4 crystal obtained by afm indicated hexagonal layers. the particle size distribution for prepared nano fe3o4 was obtained as shown in fig. 6 from fig. 6 show that the most volume percentage 12.98% of particle size distribution was at 90 nm and the lowest volume percentage 0.38 % was at 35nm and also show the prepared nano fe3o4 consisted of particles with diameters ranged between 35 100 nm this means that the particles of prepared nanofe3o4 are nanometer-sizes and the average particles diameter of nanofe3o4was 75.92nm. fig. 4. afm two-dimensional surface profiles for fe3o4 fig. 5. afm three-dimensional surface profiles for fe3o4 fig. 6. granularity cumulation distribution for prepared fe3o4 3.4. xray florescence (xrf) the chemical composition of the prepared fe3o4 was analyzed using xrf technique. table 2 represents the chemical composition of the prepared nano fe3o4 expressing in weight percent. fe and o elemental composition 69% and 28.24% respectively this value is not far from the value 71.58% for fe and 28.4% for o. table 2. the chemical composition for the prepared fe3o4 oxides, wt. % fe2o3 p2o5 cao tio2 mgo fe3o4 77.8 0.5 0.25 0.45 0.37 n. s. majeed and d. m. naji / iraqi journal of chemical and petroleum engineering91,2 (2018) 27-31 03 3.5. fourier transform infrared spectroscopy (ftir) fig. 7 illustrates the ftir spectra of prepared nano fe3o4. from this figure it can be observed that, the bands 586 is assigned to characteristic fe–o vibrations of fe3o4.the band o–h vibrations occur from 3160 to 3430 cm -1 . slight differences occur in the peaks at 3414 cm -1 representing–oh functions .the band at 1616 cm -1 is due to bending modes of the water molecules adsorbed on magnetite surfaces ‎[17]. fig. 7. ftir of synthesized nano fe3o4 4conclusion according to the results obtained from this study, nanomagnetite can be synthesized successfully by using iron (ii) chloride tetrahydrate and sodium hydroxide by open vessel ageing process. the x-ray diffraction patterns of synthesized nanomagnetite show very good agreements with standard magnetite. the value of surface area of prepared nanomagnetite was 85.97m 2 /g and the pore volume was find equal to 0.1566 cm3/g. fe and o elemental composition 69% and 28.24% respectively the average particles diameter of prepared magnetite was determine by afm analysis and it was find equal to75.92nm. references [1] begum, k. m. s., & anantharaman, n., 2009. "removal of chromium (vi) ions from aqueous solutions and industrial effluents using magnetic fe3o4 nano-particles". adsorption science & technology, 27, pp.701-722. [2] yew, y. p., shameli, k., miyake, m., kuwano, n., khairudin, n. b. b. a., mohamad, s. e. b., & lee, k. x. , 2016." green synthesis of magnetite (fe3o4) nanoparticles using seaweed (kappaphycus alvarezii) extract". nanoscale research letters, 11, pp.1-7. [3] malakootian, m., askarpuor, a., amirmahani, n., nasiri, z., & nasiri, a. ,2015, "removal of hexavalent chromium from aqueous solutions using magnetic nanoparticles coated with alumina and modified by cetyl trimethyl ammonium bromide", journals of community health research, 4, pp.177-193.‏ [4] campos, e. a., pinto, d. v. b. s., oliveira, j. i. s. d., mattos, e. d. c., & dutra, r. d. c. l. ,2015. "synthesis, characterization and applications of iron oxide nanoparticles-a short review". journal of aerospace technology and management, 7, pp.267276. [5] ríos-hurtado, j. c., múzquiz-ramos, e. m., zugasticruz, a., & cortés-hernández, d. a. ,2016. "mechanosynthesis as a simple method to obtain a magnetic composite (activated carbon/ fe3o4) for http://journals.sagepub.com/doi/abs/10.1260/0263-6174.27.7.701 http://journals.sagepub.com/doi/abs/10.1260/0263-6174.27.7.701 http://journals.sagepub.com/doi/abs/10.1260/0263-6174.27.7.701 http://journals.sagepub.com/doi/abs/10.1260/0263-6174.27.7.701 http://journals.sagepub.com/doi/abs/10.1260/0263-6174.27.7.701 https://nanoscalereslett.springeropen.com/articles/10.1186/s11671-016-1498-2 https://nanoscalereslett.springeropen.com/articles/10.1186/s11671-016-1498-2 https://nanoscalereslett.springeropen.com/articles/10.1186/s11671-016-1498-2 https://nanoscalereslett.springeropen.com/articles/10.1186/s11671-016-1498-2 https://nanoscalereslett.springeropen.com/articles/10.1186/s11671-016-1498-2 http://jhr.ssu.ac.ir/browse.php?a_id=269&sid=1&slc_lang=en http://jhr.ssu.ac.ir/browse.php?a_id=269&sid=1&slc_lang=en http://jhr.ssu.ac.ir/browse.php?a_id=269&sid=1&slc_lang=en http://jhr.ssu.ac.ir/browse.php?a_id=269&sid=1&slc_lang=en http://jhr.ssu.ac.ir/browse.php?a_id=269&sid=1&slc_lang=en http://jhr.ssu.ac.ir/browse.php?a_id=269&sid=1&slc_lang=en http://jhr.ssu.ac.ir/browse.php?a_id=269&sid=1&slc_lang=en http://www.scielo.br/scielo.php?pid=s2175-91462015000300267&script=sci_arttext http://www.scielo.br/scielo.php?pid=s2175-91462015000300267&script=sci_arttext http://www.scielo.br/scielo.php?pid=s2175-91462015000300267&script=sci_arttext http://www.scielo.br/scielo.php?pid=s2175-91462015000300267&script=sci_arttext http://www.scielo.br/scielo.php?pid=s2175-91462015000300267&script=sci_arttext http://www.scielo.br/scielo.php?pid=s2175-91462015000300267&script=sci_arttext http://www.scirp.org/journal/paperinformation.aspx?paperid=62568 http://www.scirp.org/journal/paperinformation.aspx?paperid=62568 http://www.scirp.org/journal/paperinformation.aspx?paperid=62568 http://www.scirp.org/journal/paperinformation.aspx?paperid=62568 n. s. majeed and d. m. naji / iraqi journal of chemical and petroleum engineering91,2 (2018) 27-31 03 hyperthermia treatment". journal of biomaterials and nanobiotechnology, 7, pp.19-28 [6] xu, p., zeng, g. m., huang, d. l., feng, c. l., hu, s., zhao, m. h., & liu, z. f. ,2012." use of iron oxide nanomaterials in wastewater treatment: a review". science of the total environment, 424, pp. 1-10. [7] zhang, y., liu, j. y., ma, s., zhang, y. j., zhao, x., zhang, x. d., & zhang, z. d. ,2010. "synthesis of pvp-coated ultra-small fe3o4 nanoparticles as a mri contrast agent". journal of materials science: materials in medicine, 21(4), pp.1205-1210.‏ [8] chomoucka, j., drbohlavova, j., huska, d., adam, v., kizek, r., & hubalek, j. ,2010. "magnetic nanoparticles and targeted drug delivering". pharmacological research, 62(2), pp. 144-149. [9] chin,s., pang,s.& tan,c., 2016. "green synthesis of magnetite nanoparticles (via thermal decomposition method) with controllable size and shape" . environ. sci. 2 , pp.299-302. [10] reddy, l. h., arias, j. l., nicolas, j., & couvreur, p. ,2012."magnetic nanoparticles: design and characterization, toxicity and biocompatibility, pharmaceutical and biomedical application". chemical reviews, 112, pp. 5818-5878. [11] pranita , l.& preeti,j., 2015. "preparation and characterization of magnetite nanoparticle using green synthesis". int. j. res. chem. environ., 5 ,pp.38-43. [12] khalighyan, n., hooshmand, n., razzaghi-asl, n., zare, k., & miri, r. ,2014. "response surface strategy in the synthesis of fe3o4 nanoparticles" . international journal of nano dimension , 5,pp. 421430. [13] herlekar ,m. & barve1,s., 2015. "optimization of microwave assisted green synthesis protocol for iron oxide nanoparticles and its application for simultaneous removal of multiple pollutants from domestic sewage". international journal of advanced research , 3, pp.331-345. [14] xu, j. k., zhang, f. f., sun, j. j., sheng, j., wang, f., & sun, m. 2014. "bio and nanomaterials based on fe3o4". molecules, 19, pp.21506-21528. [15] abdulghani, a. j., & al-ogedy, w. m. "synthesis and characterization of multishapes of fe3o4 nanoparticle by solve-hydrothermal method using microwave radiation". baghdad science journal,13,pp.331-339.‏ [16] mohapatra, m., & anand, s. ,2010. "synthesis and applications of nano-structured iron oxides/hydroxides–a review". international journal of engineering, science and technology, pp. 127-146. [17] lopez, j.a., gonzález, f., bonilla, f.a., zambrano, g. and gómez, m.e., 2010. "synthesis and characterization of fe3o4 magnetic nanofluid ". revista latinoamericana de metalurgia y materiales, pp.60-66. http://www.scirp.org/journal/paperinformation.aspx?paperid=62568 http://www.scirp.org/journal/paperinformation.aspx?paperid=62568 https://www.sciencedirect.com/science/article/pii/s0048969712001982 https://www.sciencedirect.com/science/article/pii/s0048969712001982 https://www.sciencedirect.com/science/article/pii/s0048969712001982 https://www.sciencedirect.com/science/article/pii/s0048969712001982 https://www.sciencedirect.com/science/article/pii/s0048969712001982 https://link.springer.com/article/10.1007/s10856-009-3881-3 https://link.springer.com/article/10.1007/s10856-009-3881-3 https://link.springer.com/article/10.1007/s10856-009-3881-3 https://link.springer.com/article/10.1007/s10856-009-3881-3 https://link.springer.com/article/10.1007/s10856-009-3881-3 https://www.sciencedirect.com/science/article/abs/pii/s1043661810000289 https://www.sciencedirect.com/science/article/abs/pii/s1043661810000289 https://www.sciencedirect.com/science/article/abs/pii/s1043661810000289 https://www.sciencedirect.com/science/article/abs/pii/s1043661810000289 https://www.sciencedirect.com/science/article/abs/pii/s1043661810000289 https://spiral.imperial.ac.uk/handle/10044/1/18318 https://spiral.imperial.ac.uk/handle/10044/1/18318 https://spiral.imperial.ac.uk/handle/10044/1/18318 https://spiral.imperial.ac.uk/handle/10044/1/18318 https://pubs.acs.org/doi/abs/10.1021/cr300068p https://pubs.acs.org/doi/abs/10.1021/cr300068p https://pubs.acs.org/doi/abs/10.1021/cr300068p https://pubs.acs.org/doi/abs/10.1021/cr300068p https://pubs.acs.org/doi/abs/10.1021/cr300068p http://www.ijnd.ir/article_5704_773.html http://www.ijnd.ir/article_5704_773.html http://www.ijnd.ir/article_5704_773.html http://www.ijnd.ir/article_5704_773.html http://www.ijnd.ir/article_5704_773.html http://www.journalijar.com/uploads/885_ijar-5387.pdf http://www.journalijar.com/uploads/885_ijar-5387.pdf http://www.journalijar.com/uploads/885_ijar-5387.pdf http://www.journalijar.com/uploads/885_ijar-5387.pdf http://www.journalijar.com/uploads/885_ijar-5387.pdf http://www.journalijar.com/uploads/885_ijar-5387.pdf http://www.mdpi.com/1420-3049/19/12/21506 http://www.mdpi.com/1420-3049/19/12/21506 http://www.mdpi.com/1420-3049/19/12/21506 https://www.iasj.net/iasj?func=article&aid=110250 https://www.iasj.net/iasj?func=article&aid=110250 https://www.iasj.net/iasj?func=article&aid=110250 https://www.iasj.net/iasj?func=article&aid=110250 https://www.iasj.net/iasj?func=article&aid=110250 https://www.ajol.info/index.php/ijest/article/view/63846 https://www.ajol.info/index.php/ijest/article/view/63846 https://www.ajol.info/index.php/ijest/article/view/63846 https://www.ajol.info/index.php/ijest/article/view/63846 http://www.scielo.org.ve/scielo.php?script=sci_arttext&pid=s0255-69522010000100007 http://www.scielo.org.ve/scielo.php?script=sci_arttext&pid=s0255-69522010000100007 http://www.scielo.org.ve/scielo.php?script=sci_arttext&pid=s0255-69522010000100007 http://www.scielo.org.ve/scielo.php?script=sci_arttext&pid=s0255-69522010000100007 http://www.scielo.org.ve/scielo.php?script=sci_arttext&pid=s0255-69522010000100007 iraqi journal of chemical and petroleum engineering vol.16 no.4 (december 2015) 3143 issn: 1997-4884 electrolytic removal of zinc from simulated chloride wastewaters using a novel flow-by fixed bed electrochemical reactor sawsan a. m. mohammed 1 , abbas hamid sulaymon 2 , ali hussein abbar 3 1 chemical engineering department, university of baghdad, iraq 2 environmental engineering department, university of baghdad, iraq 3 chemical engineering department, al-qadissya university, iraq abstract the cathodic deposition of zinc from simulated chloride wastewater was used to characterize the mass transport properties of a flow-by fixed bed electrochemical reactor composed of vertical stack of stainless steel nets, operated in batch-recycle mode. the electrochemical reactor employed potential value in such a way that the zinc reduction occurred under mass transport control. this potential was determined by hydrodynamic voltammetry using a borate/chloride solution as supporting electrolyte on stainless steel rotating disc electrode. the results indicate that mass transfer coefficient (km) increases with increasing of flow rate (q) where .the electrochemical reactor proved to be efficient in removing zinc and was able to reduce the levels of this metal to lower than 0.7 ppm starting from initial concentration of 48.4 mg dm -3 ppm in 120 minutes using ratio of cathode volume/catholyte volume equal to 0.0075. sherwood and reynolds numbers were correlated to characterize the mass transport properties of the reactor as follows: key words: heavy metals, electrochemical reactor, zinc, flow-by electrode, mass transfer introduction preventing of pollution and environmental damage by industrial waste causes governments to implement stricter environmental legislation. industrial wastewater containing toxic ions represents a challenging case owing to the difficulty of removing these ions by biodegradation [1]. pollution by toxic metals including cu, cd, cr, pb, hg and zn is generated by a wide range of manufacturing industries such as mining, metal finishing, electroplating, photographic development, printed circuit board production and battery [2]. several methods have been used to remove toxic metals from wastewater effluents; including chemical precipitation [3], electrodialysis [4], ion exchange process [5,6], adsorption onto activated carbon [7, 8], low cost adsorbents such as kaolin, bentonite, blast furnace slag and fly ash [9 ], ion imprinted polymer [10], organic-based ligand precipitation [11], membrane and reverse osmosis processes [12]. the industrial utilization of these methods has been found to be limited, because of the high capital and iraqi journal of chemical and petroleum engineering university of baghdad college of engineering electrolytic removal of zinc from simulated chloride wastewaters using a novel flow-by fixed bed electrochemical reactor 32 ijcpe vol.16 no.4 (dec. 2015) -available online at: www.iasj.net operating costs and/or the ineffectiveness in meeting stringent effluent standards [13]. electrochemical removal technology by cathodic deposition gives an efficient mean of controlling pollution through the removal of transition and heavy metals by redox reactions, without the shortcomings of conventional treatments. the main advantage of this technology is its environmental compatibility due to the fact that the main reagent, the electron, is a ‗clean reagent‘ [14]. the using of porous materials as three dimensional electrodes in the design of electrochemical reactors led to increase the use of electrochemical technologies in the environmental treatment [15]. the main advantages of this kind of electrode are having high specific surface area as well as high mass transfer rate. two principal configurations for the three dimensional electrodes have been developed: the flow-through configuration in which the fluid flows parallel to the current; and the flow-by configuration, where the fluid flows perpendicularly to the current[16]. unfortunately the flowthrough porous electrode does not prove its efficiency on the industrial scale because of the non-uniform current and potential distribution, poor selectivity and low conversion per pass [17]. to avoid these shortcomings attention has been directed to the flow-by electrode [18-20]. several types of flow-by electrode have been used industrially in removing of heavy metals, for example, carbon or metal particles [21,22], metallic or metal plated foams and felts [23,24] ,and reticulated vitreous carbon (rvc) [25]. however, these electrodes suffer from many problems like the clogging of the pores due to the continuous metal deposition and high pressure drop. besides, metal felt and metal foam fixed bed electrodes may entrap gas bubbles (h2) which are likely to evolve simultaneously with the main reaction from dilute solutions with a consequent increase in cell resistance and electrical energy consumption [26]. the use of screens as three dimensional electrodes offers many advantages, such as high specific area, high turbulencepromoting ability, high porosity and relatively low pressure drop, ease of coating with a catalyst, and ready availability at modest cost [27-31]. in addition, they present a rigid structure and are relatively easy to construct. most of electrochemical reactors are operated via two modes of operation, namely batch recirculation and oncethrough flow. in the former mode product from cell is mixed with the feed and the liquor concentration gradually decreases in value during operation until the required terminal concentration is achieved. in the latter the inlet and outlet cell concentration remain constant with time and process is ended when all the liquor is passed through the cell [32].to maintain a high recovery or removal efficiency in once through systems, the electrolyte has to pumped very slowly through the electrode. sioda [33] gave an equation for calculation of this critical velocity corresponding to complete reaction controlled by diffusion. too low flow rate, however, is also not practical when thousands of gallons of effluents have to be treated. a recirculation operation is thus more adapted for industrial application and its behavior has been investigated theoretically by considering the porous electrode as the analog of a chemical reactor [34-36]. most of previous works on the removal of heavy metals using a flowby electrochemical cell composed of stack of nets were carried out using once through or single –pass flow mode of operation where mass transfer sawsan a. m. mohammed, abbas hamid sulaymon, ali hussein abbar -available online at: www.iasj.net ijcpe vol.16 no.4 (dec. 2015) 33 correlations that describe this system have been determined [37-40]. however no previous work was conducted to removal of zinc using screens as a flow-by fixed bed electrochemical reactor operated at either single–pass flow or batch recirculation mode. the purpose of this work was to develop an improved reactor design that is easy to fabricated and operated at batch recycle model where the mass transfer correlation was determined and compared with previous works. the choice of stainless steel as cathode material in this study is based on the observation of previous works that stainless steel has been proved to be very effective as a cathode for metal removal from wastewaters [41-43]. this material showed a good stability as cathode and could also be anodically polarized during its regeneration process without damage. furthermore, stainless steel is an inexpensive material when compared with graphite felt or reticulated vitreous carbon which has been extensively used in wastewaters treatment. experimental work the development of the electrolytic cell for zinc removal was carried out in two stages. initially, a voltammetric study of the zn(ii) reduction on a stainless steel rotating disc electrode was performed in order to determine the potential over which this reaction is controlled by mass-transfer. subsequently, the selected potential was applied to a flow-by electrolytic cell containing a stack of stainless steel screens cathode. all reagents were of analytical grade and did not undergo further purification. distilled water was used to prepare all solutions. metallic ion solutions were prepared in such a way that the metallic concentration was around 50 mg/l. zinc solution was prepared from zncl2 plus 0.5m nacl and 0.1 m h3bo3 with a final ph of 5. solution viscosity and density were determined by an ostwald viscometer and density bottle, respectively [44].table 1 represents the physical properties of electrolytic solution. table 1, physical properties of the solution at 25°c property value concentration(ppm) 50 density(g/cm 3 ) 1.0471 kinematic viscosity(cm 2 /s) 0.00915 electrochemical experiments were controlled with an electric circuit consisting of power supply (model uni-t: utp3315tf-l), resistance boxes, ammeter and voltmeter. all experiment were performed at 25±1ºc.the hydrodynamic voltammetric experiments were carried out in a conventional three-electrode cell with separated compartments for each electrode. a stainless steel (316aisl) rotating disc electrode as a working electrode with an active cross sectional area of 0.0314 cm 2 , a largesurface platinum counter-electrode, and a saturated calomel reference electrode (sce) within a luggin capillary, were used. the stainless steel electrode was polished to a mirror-like surface, using emery paper of grade 600 (3m). the current-voltage curves were obtained for several rotation speeds (400, 800, 1200, 1600, and 2000 rpm) by linear sweep of the working electrode potential starting from open circuit potential to the more cathodic potential up to -1600 mv vs. sce. the dual continuous-flow cell design is shown schematically in fig.(1).it consists of an electrochemical cell, two 5-l capacity perspex reservoirs for the catholyte and the anolyte, two magnetic recirculation pumps(eheim electrolytic removal of zinc from simulated chloride wastewaters using a novel flow-by fixed bed electrochemical reactor 34 ijcpe vol.16 no.4 (dec. 2015) -available online at: www.iasj.net kerisel), and two sets of flowmeters, with a flow range from 60 to 480 l/h, for controlling the catholyte and anolyte flow rates. these components were connected together by polyvinylchloride tubes. the flow-by reactor design in this study was based on the criteria established by risch and newman [45]. according to risch and newman criteria, a flow-by reactor with an aspect ratio of the electrode length to thickness, l/t > 5, will produce a higher maximum processing rate than a flow-through configuration. the aspect ratio of present cell is 33.33. the electrolysis cell, which is shown in fig.(2), was basically a rectangular flow channel constructed from two machined blocks of poly tetrafluoroethylene(ptfe).the first is the cathodic chamber having external dimensions(30x14x2.5cm) while the second is the anodic chamber with dimensions (30 x14 x 3.5 cm).the anodic chamber has two cavities; internal (10 x10 x2.2 cm)in which graphite block (10 x10 x2 cm) working as anode was fixed ,and external (24 x10 x0.5 cm)in which the anolyte is flowing over anode upward. the anode was grooved lengthwise to increase its surface area. the cathode chamber has also two cavities; internal (10x10x0.6cm) in which copper plate (10x10x0.5cm) working as current feeder was fixed, and external (24x10x0.3cm) in which the catholyte passes through two stacks of screens: the first consisted seven polypropylene meshes with mesh number (30wire/inch) working as calming zone. the second consisted five stainless steel screens (316-aisi) of mesh number (30 wire/inch) working as flow-by. the current feed to the electrodes was provided by screw connectors through the walls of the cell. a saturated calomel reference electrode within a teflon luggin capillary entered the cathode chamber through a 3mm-hole drilled from the back near the copper plate. the anodic and cathodic chambers were separated from each other by a cationic membrane (ionic-64lmr) which was supported on both sides with 2mm thickness ptfe perforated plates. the cell was held vertically and the electrolytes were circulated upwards. the flow system was loaded with 4.0 liters of catholyte and anolyte, each in a separate reservoir. fig.1, schematic view of the batch recirculation electrochemical system the catholyte was composed of 0.5m nacl and 0.1 m h3bo3 with zinc concentration of 50 ppm at final ph of 5. the anolyte composition was the same as the catholyte, with the exception of the metal ions, and the flow rates of both electrolytes were adjusted to the same value. sawsan a. m. mohammed, abbas hamid sulaymon, ali hussein abbar -available online at: www.iasj.net ijcpe vol.16 no.4 (dec. 2015) 35 fig. 2, the flow-by electrochemical cell the catholyte was purged with high purity nitrogen (99.999%) for 30 min to prevent contamination with oxygen. a constant potential (determined from voltammetry experiment) for reduction of zinc at the limiting conditions was applied to the cell from the power supply, in the controlled-potential mode, for two hours. at predetermined intervals, the solution leaving the cathodic compartment was sampled, and the remaining metal concentration was quantified by atomic absorption spectrometry (varian spectraa 200 spectrometer), in order to monitor the effectiveness of electrolysis. the properties of this screen{ opening size of screen(d) cm , porosity(ε) and specific surface area(a) cm -1 } were calculated using equations of armour and cannon[46].the properties of this screen are shown in table 2. table 2, screen parameters mesh number wire/inch 30 woven type plain square wire diameter(cm),d 0.03 opening size(cm),d 0.0547 screen porosity, ε 0.7048 specific area (cm -1 ),a 39.366 discussion 1hydrodynamic voltammetric experiments fig.(3)shows polarization curves corresponding to zinc electrodeposited on stainless steel rotating disc electrode for several rotation speeds (400, 800, 1200, 1600, and 2000 rpm). the voltammograms show a limiting current zone in the potential range from -1160 to -1350 mv vs. sce. under such conditions, the reaction rate is limited by the mass transport rate and the limiting current at the smooth rotating disc in laminar flow can be predicted by the levich equation [47]: ... (1) where il is the limiting current ma, a is the area of electrode cm 2 , d is the diffusion coefficient cm 2 /s, ω is the rotation rate rad/ s, ν is the kinematic viscosity of the electrolyte cm 2 /s and cb is the bulk concentration(mol/ cm 3 ). fig. 3, linear voltammetric curves for reduction of zinc on stainless steel rotating disc electrode at different rotation speeds: [zn] =50 ppm supporting electrolyte (0.5 m nacl +0.1 m h3bo3), ph=5 electrolytic removal of zinc from simulated chloride wastewaters using a novel flow-by fixed bed electrochemical reactor 36 ijcpe vol.16 no.4 (dec. 2015) -available online at: www.iasj.net to investigate whether the reduction of zinc occurred under mass transfer condition, the limiting currents were calculated from the polarization curves and plotted against ω 1/2 as shown in fig.(4-a) .the limiting current is found at the middle point of a straight line that follows the plateau region and is limited by emax and emin [48]. (a) (b) fig. 4, (a) levich plots for the limiting currents taken at potentials of -1260 mv for total reduction (zinc and hydrogen) and zinc reduction (b) linear voltammetric curves without zinc on stainless steel rotating disc electrode at different rotation speeds these values are the points at which the straight line departs from the i vs. e curve. the results indicate that the reduction of zinc is under mass transfer control. during the zinc metals electrodeposition, hydrogen evolution is always a competitive parallel process.in this case hydrogen evolution amplifiers the response without apparently changing its shape. thus, in order to correctly determine the zn +2 diffusion coefficients in the supporting electrolyte, it was necessary to bubble n2 in the solution to eliminate dissolved o2 and to discount the hydrogen contributions to the total current density. fig.(4-b) shows the voltammogrames recorded using the supporting electrolyte(0.5 m nacl + 0.1m h3bo3) and ph=5 without zinc under the same rotations as those employed to obtain the data shown in figure (3), so that the current densities recorded under the potentials of mass transfer of this metal resulted exclusively from the reduction of hydrogen. data of the best fit of the limiting current of zinc only from fig. (4-a) were used to estimate the diffusion coefficient of zinc at 50 ppm, using the levich equation. taking the value of the electrolyte kinematic viscosity from table (1),the value of diffusion coefficient of zinc in the present work was estimated to be 17.7 x 10 -6 cm 2 /s which is slightly higher than those obtained at the previous works [49, 50].the reason may be the effect of boric acid used in the present work. 2cell performance for electrolytic copper removal the use of the batch recirculation (or batch recycle) mode is a versatile strategy that allows the operator to adjust the volume of the system, monitoring and controlling the concentration of ions and ph [51]. modelling of the batch recirculation sawsan a. m. mohammed, abbas hamid sulaymon, ali hussein abbar -available online at: www.iasj.net ijcpe vol.16 no.4 (dec. 2015) 37 plug flow reactor is more complex than that of the single pass plug flow reactor as both the reactor and reservoir have time dependent concentrations associated with them. a rigorous model of concentration-time relationships in recirculating electrochemical reactor system has been proposed by walker and wragg[35], however, it is possible to simplify this model by manipulating the setup such that pseudo-steady state, isothermal conditions are achieved. a pseudo-steady state system is approached by the use of a reservoir with a far greater volume than that of the reactor, such that the change in concentration with time at any given point in the reactor is insignificant in comparison to the change in concentration with distance through the reactor. consequently the change in concentration as a function of time can be described by the following equation [52]: ( ) ( ) , * ( )+ ... (2) where c(t) is the concentration at time t (mole/cm 3 ), c(0) is the initial concentration(mole/cm 3 ), q is catholyte flow rate (cm 3 /s), vr is catholyte volume (cm 3 ), km is mass transfer coefficient(cm/s), a is specific surface area (cm -1 ),l is cathode length(cm) and u is superficial velocity (cm/s). eq. (2) can be written as follows: ( ) ( ) ... (3) where s is the slope of logarithmic concentration against time, from which mass transfer coefficient can be calculated as follows: ( ) ... (4) where vc is the cathode volume (cm 3 ). (a) (b) fig. 5, (a) normalized concentration [c(t) /c(0)] against time curves for zinc removal experiments at different flow rate, (b) plots of ln[c(t) /c(0)] against time. walker and wragg[35] found that this approximated model can be applied for a reactor: reservoir volume ratio of higher than1:100.in the present work the ratio is 30cm 3 :4000cm 3 (1:133.333) which is in agreement with the assumption of the approximated model. fig. (5-a and b) shows the plot electrolytic removal of zinc from simulated chloride wastewaters using a novel flow-by fixed bed electrochemical reactor 38 ijcpe vol.16 no.4 (dec. 2015) -available online at: www.iasj.net of normalized concentration (c(t) /c(0)) as a function of time and the linearized concentration profile for different flow rates. the data show that as the flow rate increases, the removal of zinc become more effective, this behavior was attributed to a greater rate of mass transport of zinc ions due to an increase in the electrolyte flow rate. although the plots of c(t) /c(0) as a function of electrolysis time were apparently exponential. table (3) shows values of initial concentrations, c (0), the times for 90% and 99% removal, and values of km as a function of flow rate. also fig. (6) depicted the relation between of km and q. it is clear that km increases with q raised to the power of 0.402. table 3, effect of the flow rate on the removal rate of zinc from chloride medium, ph 5.0, five screens, mesh no.30 (wire/inch) q (l/h) c(0) (ppm) t90% (s) t99% † (s) km(cm/s) x10 -3 c ‡ (ppm) 120 48.6 6000 9600 1.2819 3.3 180 50.6 4800 8280 1.5284 1.8 240 47.9 4560 8160 1.6741 1.3 300 49.3 3600 6960 1.8319 < 1.4 360 49.7 3390 6780 2.0234 < 1.4 420 48.4 2940 5940 2.6619 < 0.7 †these values were calculated based on linear extrapolation ‡electrolysis time =120 min table (4) represents values of re, km, and sh for zinc deposition reaction and fig. (7) shows plots of the log ( shsc -1/3 ) against log(re). a best fit line was used to correlate the data of the power relation as follows: in terms of sherwood number ... (4) in terms of jd ... (5) where re=ρudw/μ, sh=kmd/d, sc=μ/ρd, jd=sh/ (resc 1/3 ). the linear correlation coefficient is 99.394%. this correlation was established for reynolds number 52 ≤ re ≤ 180 and schmidt number (sc)=2362.5 fig. 6, the relation between mass transfer coefficient and flow rate in zinc removal. table, 4, values of re and sh and their respective logarithmic values for the removal rate of zinc, ph 5.0, five screens, mesh no.30 (wire/inch) re sh sh/sc 1/3 log( re) log(sh /sc 1/3 ) 51.6915 2.1728 0.2707 1.7134 -0.5675 77.5372 2.5905 0.3228 1.8895 -0.4911 103.3829 2.8375 0.3536 2.0145 -0.4515 129.2287 3.1049 0.3869 2.1114 -0.4124 155.0744 3.4295 0.4273 2.1905 -0.3693 180.9202 4.5116 0.5621 2.5749 -0.2501 sawsan a. m. mohammed, abbas hamid sulaymon, ali hussein abbar -available online at: www.iasj.net ijcpe vol.16 no.4 (dec. 2015) 39 no previous work on removal of zinc using screens electrode has been conducted, only sabri [53] studied the removal of zinc using flow through electrode operated on batch recycle model. the obtained correlation was as follows: ... (6) table 5, comparison of sabri results with present work author electrolyte q l/h c(0) ppm c t=100min (ppm) re (%) sabri [53] 0.1mkcl ,0.1mh3bo3 120 44.16 10.56 76.087 240 43.2 7.2 83.333 this work 0.5m nacl , 0.1m h3bo3 120 48.6 4.9 89.918 240 47.9 2.4 94.989 fig. 7, log (sh/sc 1/3 ) verses log (re) the exponent of re in the present work is somewhat higher than sabri, however the correlation constant in eq.(6) is higher than obtained in the present work leading to a higher mass transfer. this behavior was expected because the system in sabri work was flow through in which jetting effect is occurred which leads to higher mass transfer as approved by sedahem [54]. the removal efficiency of present work is much higher than sabri work as shown in table (5).this is an indication that hydrogen evolution in sabri work is higher than the present work. lanza and bertazzoli[55] investigated removal of zinc using rvc electrode and chloride solution at batch recycle mode ,in spite of no mass transfer correlation was determined ,they studied the effect of different variables on mass transfer coefficient. table (6) shows the comparison between the present work and results of lanza and bertazzoli for rvc having specific surface area 37.4cm -1 which is closer to the surface area of screens used in this work. table 6, comparison of lanza and bertazzoli results with present work q q l/h c(0) ppm t90% (s) t99% (s) km(cm/s) x10 -3 lanza and bertazzoli [55] 120 54.4 1500 1680 1.83 this work 120 48.6 6000 9600 1.2819 it is clear that t90% and t99% is lower in lanza and bertazzoli work, this is because the ratio(vr/vc) is 37 while in the present work is 133.33 therefore they modeled their system as a simple batch not as batch recycle mode in spite of their working at batch recycle mode. with (vr/vc) equal to 133, it was expected that electrolysis time is higher than lanza and bertazzoli system if the system operated at higher current efficiency as the case of present work. the increasing of mass transfer in lanza and bertazzoli work may be resulted from evolution of hydrogen gas due to decreasing the concentration during the electrolysis which is expected since (vr/vc) is lower than 100. conclusions a flow-by vertical stack of nets electrode has been used effectively for the removal of zinc ions from diluted electrolytic removal of zinc from simulated chloride wastewaters using a novel flow-by fixed bed electrochemical reactor 40 ijcpe vol.16 no.4 (dec. 2015) -available online at: www.iasj.net solutions. hydrodynamic voltammetry proved to be adequate for studying the zinc reduction under mass transport control. the concentration of zinc was reduced from 48.4 ppm to less than 0.7 ppm in batch recirculation mode at flow rate of (420l/h) with electrolysis time 120 minutes operated under constant cathode potential. this behavior cannot be achieved in single pass-flow mode at this initial concentration and flow rate. the ratio between the time of electrolysis for concentration reduction of 99% and that for concentration reduction 90% is about two for most of the experiments. this is an evidence of a mass transport controlled process. most of previous works on removal of zinc using other electrode materials operated on batch recycle mode used a ratio of catholye volume to cathode volume ≤100, this ratio in the present work higher than (130) leading to less than 2% error in adapting the approximated model eq. (2) according to walker and wragg observations [35].therefor the present results are more accurate and compatible with the batch –recycle model assumptions. acknowledgment the authors express their gratitude to engineering consulting bureau/ alqadissya university for financial support of this work under the contract no.28-2.special thanks are also due to the technical staff of chemical engineering department, university of baghdad for their support and assistance. references 1w. bourgeois, j.e. burgess, r.m. stuets (2001),‖on-line monitoring of wastewater quality: a review‖, j. chem. tech. biotech.76, 337–348. 2d. pletcher, f.c. walsh (1990), industrial electrochemistry, chapman and hall. 3j.p. chen, x. wang (2000), ―removing copper, zinc, and lead ion by granular activated carbon in pretreated fixed-bed columns‖, sep. purif.technol.19, 157-167. 4i.m. ismail, m.r. el-sourougy, n. abdel moneim, h. f. aly (1999), ―equilibrium and kinetic studies of the sorption of cesium by potassium nickel hexacyanoferrate complex‖,j radioanal. nucl. chem. 240, 59-67. 5j.a.s. tenorio, d.c.r. espinosa (2001), ―treatment of chromium plating process effluents with ion exchange resins‖, waste management 21, 637-642. 6s. kocaoba, g. akcin (2005), ―removal of chromium (iii) and cadmium (ii) from aqueous solutions‖, desalination180, 151156. 7j. patterson (1985), industrial wastewater treatment technology. 2nd ed. boston: butterworth publisher. 8m. kazemipour, m. ansari, s.h. tajrobehkar (2008), ―removal of lead, cadmium, zinc, and copper from industrial wastewater by carbon developed from walnut, hazelnut, almond, pistachio shell, and apricot stone‖, j hazard. mater.150, 322–327. 9p.c. mishraa, r. k. patel (2009),‖removal of lead and zinc ions from water by low cost adsorbents‖, j hazard. mater.168, 319–325. 10t. alizadeh, s. amjadi (2011), ―preparation of nano-sized pb 2+ imprinted polymer and its application as the chemical interface of an electrochemical sensor for toxic lead determination in different real samples‖, jhazard.mater.190, 451-459. 11m. khajeha, z.s. heidarib, e. sanchoolia (2011), ―synthesis, characterization and removal of lead from water samples using lead-ion sawsan a. m. mohammed, abbas hamid sulaymon, ali hussein abbar -available online at: www.iasj.net ijcpe vol.16 no.4 (dec. 2015) 41 imprinted polymer‖, chem. eng. j.166, 1158-1163. 12m. mohsen-nia, p. montazeri, h. modarress (2007), ―removal of cu 2+ and ni 2+ from wastewater with a chelating agent and reverse osmosis processes‖, desalination 217, 276-281. 13g. chen (2004), ―electrochemical technologies in wastewater treatment‖, sep. purif.technol.38, 11-41. 14k. juttner, u. galla, h. schmieder (2000), ―electrochemical approaches to environmental problems in the process industry‖, electrochim.acta45,2575–2594. 15i.m. ismail, o.e. abdel-salam, t.s. ahmed (2013), ―investigation of the anodic dissolution of zinc in sodium chloride electrolyte – a green process‖ ,port electrochim.acta31,207-219. 16p. s. fedkiw (1981),‖ohmic potential drop in flow-through and flow-by porouselectrodes‖,j.electrochem.s oc.128, 831. 17f.c. walsh (1993), a first course in electrochemical engineering, (the electrochemicalconsultancy,hamps hire, uk. 18a. storck, p.m. robertson ,n. ibl (1979), ―mass transfer study of three-dimensional electrodes composed of stacks of nets‖, electrochim. acta24, 373-380. 19l. lipp, d. pletcher (1997), ―extended area electrodes based on stacked expandedtitanium meshes‖,electrochim. acta42, 1101-1111. 20m.m. letord-quemere, f. coeuret, j. legrand (1988), ―forced flow of a two-phase electrolyte through a porous electrode of expanded metal: mass transfer at the electrode— application to the reduction of nitrobenzene‖, electrochim.acta33, 881-890. 21o. e. abdel-salam,i. m. ismail, a. soliman, a. a. afify, h.m. aly(2014), ―removal of lead from industrial wastewater using flowby-porous electrode‖,portugaliae electrochimica acta, 32(1), 65-75. 22d. simonsson (1984), ―a flow-by packed-bed electrode for removal of metal ions from waste water‖, j. appl. electrochem.14, 595-604. 23a. tentorio, u. casolo-ginelli (1978), ―characterization of reticulate three dimensionalelectrodes‖,j.appl.elect rochem.8 ,195-205. 24a. montillet, j. comiti, j. legrand (1993), ―application of metallic foams in electrochemical reactors of filter-press type part i: flow characterization‖, j. appl. electrochem.23, 1045-1052. 25j. wang (1981), ―reticulated vitreous carbon—a new versatile electrode material‖,electrochim.acta26,17211726. 26a. a. shah, h. al-fetlawi, f. c. walsh (2010), ―dynamic modelling of hydrogen evolution effects in the all-vanadium redox flow battery‖, electrochim.acta55, 1125−1139. 27b. k. ferreira (2008), ―threedimensional electrodes for the removal of metals from dilute solutions: a review‖, mineral processing and extractive metallurgy review: an international journal 29:4,330-371. 28m.m. zaki, i. nirodosh, and g.h. sedahmed (2013),‖removal of hexavalent chromium from effluents by indirect reduction in a redox flow galvanic cell with mesh electrodes‖, inter. j environmental protection 3, 14-19. 29m.h. abdel aziz, i. nirodosh, ,g.h. sedahmed (2012) , ―mass transfer at vertical oscillating screen electrolytic removal of zinc from simulated chloride wastewaters using a novel flow-by fixed bed electrochemical reactor 42 ijcpe vol.16 no.4 (dec. 2015) -available online at: www.iasj.net stack in relation to catalytic and electrochemical reactor design‖, ind. eng. chem. res.51,1163611642. 30m.m. zaki, i. nirodosh, g.h. sedahmed (2007), ―mass transfer characteristics of reciprocating screen stack electrochemical reactor in relation to heavy metal removal from dilute solutions‖, chem. eng. j 126,67-77. 31r. alkire , p.k. ng (1977), “studies on flow-by porous electrodes having perpendicular directions of current and electrolyteflow‖,j.electrochem.soc. 124, 1220-1227. 32f.goodridge,k.scott(1995),‖electr ochemical process engineering, a guide to the design of electrolysis plant‖ 33r.e. sioda (1978), ―criterion of completeness of electrolysis at flow porous electrodes‖, j. appl. electrochem.8, 297-304. 34j.l. nava, e. sosa, g. carreno, c. ponce-de-leon, m.t. oropeza (2006), ―modelling of the concentration–time relationship based on global diffusion-charge transfer parameters in a flow-by reactor with a 3d electrode‖, electrochim.acta51 ,4210-4217. 35a.t.s. walker, a.a. wragg (1977), “the modelling of concentration–time relationships in recirculating electrochemical reactor systems‖, electroehim.acta22, 1129-1134. 36l.h. mustoe and a. a. wragg (1983), ―effect of flow rate and constant operating current on the behavior of a recirculating electrochemical reactor system‖, j. appl. electrochem.13, 507-517. 37a.a. mobarak, m.s.e. abdo, m.s.m. hassan , g.h. sedahmed (2000), “mass transfer behavior of a flow-by fixed bed electrochemical reactor composed of a vertical stack of screens under single and upward two phase flow‖, j. appl. electrochem.30, 1269-1276. 38j. cano, u. bohm (1977), “mass transfer in packed beds of screens‖, chem. eng. sci.32, 213-219. 39r. e. sioda (1977), ―flow-through electrodes composed of parallel screens‖, electrochim.acta22, 439443. 40r.e. sioda (1976), ―mass transfer problems in electrolysis with flowing solution on single and stacked screens‖, j.electroanal.chem.70, 49-54. 41d. barnes (1991), t.r. raponi, miner. metall. process. 8, 128. 42 m. paidar, k. bouzek, m. laurich , j. thonstad (2000), ―application of a three-dimensional electrode to the electrochemical removal of copper and zinc ions from diluted solutions‖, water environ. res.72, 618-625. 43c. p. de leon, d. pletcher (1996), ―the removal of pb(ii) from aqueous solutions using a reticulated vitreous carbon cathode cell-the influence of the electrolyte medium‖, electrochim.acta41533541. 44a. findlay, j.k. kiitchener (1965), practical physical chemistry, longmans, london. 45t. risch, j. newman (1984), ―a theoretical comparison of flowthrough and flow-by porous electrodes at the limiting current‖, j. electrochem.soc.131, 2551-2565. 46j.c. armour , j.n. cannon (1968), “fluid flow through woven screens‖, aiche j.14 ,415-420. 47a.j. bard, l.r. faulkner (2001), electrochemical methods: fundamentals and applications, wiley, new york. 48d.r .gabe, p.a .makanjuola (1986), in: electrochemical engineering. icheme symposium series, 98,309. sawsan a. m. mohammed, abbas hamid sulaymon, ali hussein abbar -available online at: www.iasj.net ijcpe vol.16 no.4 (dec. 2015) 43 49hsie w.c., gopikanth m.l., selman j.r. (1985),‖mass transport in supported zinc halide solutions-i. effective diffusivities of zinc ―,electrochim. acta, vol. 30, pp.1371-1380. 50i. zouari and f. lapicque(1992),‖an electrochemical study of zinc deposition ina sulfate medium‖,electrochim.acta37 ,439446. 51w.p.j. ford, f. walsh, i. whyte (1992), i. chem. e. symp. ser.127, 111. 52v.d. stankovic, a.a. wragg (1995), ―modelling of timedependent performance criteria in a three-dimensional cell system during batch recirculation copper recovery‖, j. appl. electrochem.25,565-573. 53sabri, a. a. (2008), ―mass transport properties of a flowthrough electrolytic reactor using zinc reduction system‖, phd thesis, department of chemical engineering, university of technology. 54sedahmed g.h. (1996),”mass transfer behavior of a fixed bed electrochemical reactor with a gas evolving upstream counter electrode”, the canadian journal of chemical engineering, vol74, pp.487-492. 55lanza m.r.v. and bertazzoli r. (2000)‖removal of zn (ii) from chloride medium using a porous electrode: current penetration within the cathode“,j. appl. electrochem., vol.30, pp. 61-70. iraqi journal of chemical and petroleum engineering vol.17 no.1 (march 2016) 8397 issn: 1997-4884 extraction of phenol from aqueous solutions using bulk ionic liquid membranes sawsan a.m. mohammed* and mohammed saadi hameed *university of baghdad, college of engineering, chemical engineering department abstract room temperature ionic liquids show potential as an alternative to conventional organic membrane solvents mainly due to their properties of low vapour pressure, low volatility and they are often stable. in the present work, the technical feasibilities of room temperature ionic liquids as bulk liquid membranes for phenol removal were investigated experimentally. in this research several hydrophobic ionic liquids were synthesized at laboratory. these ionic liquids include (1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide[bmim][ntf2], 1-hexyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide[hmim][ntf2], 1-octyl-3-methylimidazolium bis (trifluoromethylsulfonyl)imide[omim][ntf2],1‐butyl‐1‐methylimidazoliumhexafluor ophosphate[bmim][pf6], 1‐hexyl‐1‐methylimidazoliumhexafluorophosphate[hmim][pf6], 1-butyl-1methylpyrrolidinium bis (trifluoromethylsulfonyl) imide[bmpyr][ntf2], and 1-octyl3-methyl imidazolium tetra fluoroborate[omim][bf4]. the distribution coefficients for phenol in these ionic liquids were measured at different ph values and found to be much larger than those in conventional solvents. through the values of the distribution coefficients and the experiments that were conducted on bulk liquid membrane applying various types of prepared ionic liquids, 1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide was selected as the best ionic liquid which gave the highest extraction and stripping efficiencies. the effect of several parameters, namely, feed phase ph(2-12), feed concentration(100-1000 ppm), naoh concentration(0-0.5m), temperature (20-50 o c), feed to membrane volume ratio (200-400ml/80ml ionic liquid) and stirring speeds(75125 rpm) on the performance of the choosen ionic liquid membrane were also studied. the preliminary study showed that high phenol extraction and stripping efficiencies of 97% and 95% respectively were achieved by ionic liquid membrane with a minimum membrane loss which offers a better choice to organic membrane solvents. key words: liquid membrane, phenol, pollutants, ionic liquids, cation, anion, extraction efficiency, stripping efficiency, distribution coefficient. introduction phenol and its compounds are known to be quite poisonous pollutants. phenols are frequently produced as wastes from various industries, such as refineries, petrochemical manufacturing, coking operations, coal processing, coal gasification iraqi journal of chemical and petroleum engineering university of baghdad college of engineering extraction of phenol from aqueous solutions using bulk ionic liquid membranes 84 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net liquefaction processes, pharmaceutical plastics, wood products, paint, and pulp and paper industries. consequently, phenols must be separated from waste water before discharge to the environment. among the accessible treatment techniques, liquid membrane has been evidenced to be one of the most fascinating and efficient method for the extraction of pollutants. liquid membrane is selective permeability barrier which is separating the feed phase and stripping phase allowing the passage of the target material between those phases. this process merges those transporting processes which are extraction and stripping processes in a single stage, so supplying lower total cost, simple technically, and without relying on the transport equilibrium restriction [1]. ionic liquids are defined as a set of low melting point salts that comprise of organic cations and organic/inorganic anions. as a result of their negligible volatility, high thermal stability, high electrical conductivity, they perform as “green solvents” and their characteristics can be controlled in accordance with the purpose of design. these brilliant properties aid them as an option to substitute the volatile organic solvents [2]. the choice of a correct solvent is the major problem in all types of liquid membrane-based separation procedures. the selected solvent should possess a high distribution coefficient and at the same time it should have the following properties: insoluble in the aqueous solution, nonviscous and non-volatile. the performance of different solvents must be inspected by evaluation of distribution coefficients (kd) of the solute in required solvents [3]. the main purpose of this study was to investigate the removal of phenol from aqueous solution using bulk ionic liquid membrane as a separation method. the effect of various process parameters on the extraction process, including: ionic liquid type, ph of feed phase, feed concentration, sodium hydroxide concentration in stripping phase, agitation speeds and temperature were also studied. experimental work the phenol was provided from sigma aldrich, naoh pellets type sigma aldrich, hcl type sigma aldrich (conc. =37%w, density=1.2g/ml and formula weight=36.46 g/mole) and the materials that were used in the synthetizing of ionic liquids are given in the table 1. table 1, names of chemicals used in synthesis of ionic liquids name of materials formula weight source 1 1-methylimidazole 82.10 sigma aldrich 2 n-methylpyrrolidine 85.15 sigma aldrich 3 1-bromobutane 137.02 sigma aldrich 4 1-bromohexane 165.07 sigma aldrich 5 1-bromooctane 193.12 sigma aldrich 6 bis(trifluoromethane) sulfoni-mide lithium salt 287.09 sigma aldrich 7 sodium hexafluorophosphate 167.95 sigma aldrich 8 sodium tetrafluoroborate 109.79 sigma aldrich 9 acetonitrile 41.05 sigma aldrich 10 diethyl ether 74.12 sigma aldrich 1preparation of ionic liquids [bmim][ntf2], [hmim][ntf2], [omim][ntf2], [bmim][pf6], [hmim][pf6], [bmpyr][ntf2] and [omim][bf4] were synthesized sawsan a.m. mohammed and mohammed saadi hameed -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 85 according to the procedure described in literature [4]. a. alkylation the alkylation of 1-methylimidazole and n-methylpyrrolidine was performed as follows: a 1-liter, two-necked, roundbottomed flask provided with a heating oil bath (heated by magnetic stirrer and hot plate), an internal thermocouple adapter, and a reflux condenser were utilized for the synthesizing of ionic liquid as shown in figure 1. the flask was charged with 81.0 g (≈1mole, formula weight =82.10 g/mole) of 1methylimidazole, 100 ml of acetonitrile (ch3cn) and 164.424 g (1.20 mole, 20%excess, formula weight =137.02 g/mole) of 1bromobutane, and brought to a gentle reflux (7580°c internal temperature). the solution was heated under reflux for 72 hr and then cooled to room temperature. the following reaction took place: the volatile material was separated from the produced yellow solution under reduced pressure, and the drying step was carried out by: 1drying by rotary vacuum evaporator (figure 2): rotary evaporator is used to remove the large volumes of organic solvents. this procedure is usually used in removing organic solvents from ionic liquid products. 2high vacuum lines: vacuum lines are used in laboratory, most often for the removal of residual solvents from previously prepared ionic liquids. there are two types of vacuum lines available, the double manifold vacuum line (shown in figure 3), and the single manifold vacuum line which operates by the same general principle. the product, [bmim][br], is slightly yellow and may crystallize at room temperature, depending on the amount of water present in that phase. the same procedure was used as indicated for [bmim][br] with the use of 1-bromohexane(formula weight =166.06 g/mole) instead of 1bromobutane. 1-bromoctane (formula weight =193.12 g/mole) was used instead of 1-bromobutane to prepare [omim][br] and the produced [omim][br] was washed with diethyl ether (a volume approximately equal to half of [omim][br]). the diethyl ether was decanted followed by adding fresh diethyl ether and this step was repeated two times. washing with diethyl ether should serve to separate any unreacted material from produced [omim][br]. after the third decanting of diethyl ether, any residual diethyl ether was separated by heating the bottom phase to 70 °c and agitating while on a vacuum line. the product, [omim][br], is slightly yellow and could crystallize at room temperature, depending on the quantity of water existing in that phase. for the synthesis of 1-butyl-1-methyl pyrrolidinium bromide [bmpyr][br], n-methylpyrrolidine (formula weight =85.15 g/mole) was used instead of 1methylimidazol as indicated in the following reaction: extraction of phenol from aqueous solutions using bulk ionic liquid membranes 86 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net fig. 1, synthesis arrangement for alkylation process of 1-metylimidozole fig. 2, rotary vacuum dryer fig. 3, high vacuum line.a, b, c, d and e are valves. b. anion exchange the anion of the bromide containing ionic liquids was exchanged according to literature [5] [bmim][ntf2] was synthesised from 0.5 mole(109.56g) of [bmim][br] which was dissolved in 200 ml of distilled water followed by the slow adding of bis(trifluoromethane) sulfonimide lithium salt( lintf2) solution [0.55mole(10%excess mole), 157.89 g in 150 ml distilled water] with stirring at room temperature. after adding of lintf2 solution in [bmim][br] solution, the colour of solution was altered to milky white and two layers were separated ,then the reaction mixture was agitated for 6 hrs. after mixing, two phases were formed; the bottom phase was [bmim][ntf2] and the top phase was aqueous lithium bromide (libr). the reaction mixture was then transported into a separation funnel and [bmim][ ntf2] was separated with distilled water. after decanting the top phase, 200 ml of fresh distilled water was thoroughly mixed with the solution. this was repeated two times. the following reaction took place: for the synthesis of [hmim][ ntf2, [omim][ ntf2], and [bpyr][ ntf2] the same procedure was used as for [bmim][ ntf2]. the above procedure reported for synthesis of [bmim][ntf2] was followed for synthesizing [bmim][pf6] also. here instead of lintf2, napf6 was added to [bmim][br]solution. the following reaction took place: sawsan a.m. mohammed and mohammed saadi hameed -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 87 for synthesizing [omim][bf4] nabf4 was added to [omim][br] solution instead of lintf2. the following reaction took place: 2determination of distribution coefficient the experiment was carried out at (21±1 ◦c). a 1000 ppm of phenol solution was prepared by dissolving theoretical amount of crystal phenol in distilled water. the mixture of extraction consists 2.0 ml of such a solution and 1.0 gm of pure ionic liquid. the stoppered glass was used as a container of contacting materials .the mixture of extraction was vigoursly stirred for 30 min. an uv spectrophotometer (perkin elmer lambda 950) was used to measure the concentrations of phenol at 269.6nm. the concentration of phenol in organic phases can be determined by material balance. the distribution ratio (kd) of the phenol between an organic phase and aqueous solutions was defined by equation1: w il d c c k  … (1) where: cil and cw refer to equilibrium concentration of the solute in organic phase and in aqueous phase, respectively. 3bulk ionic liquid membrane experiment a borosilicate glass cell with dimensions of 12cm length, 6 cm width and 12 cm height was used to perform the experiments. the cell consisted of two equal compartments; the partition wall was 0.2 cm thickness at the middle of cell. this wall rises from the bottom by a distance of 8 cm in order to allow for the transfer of phenol from one section to another. a volume of 80 ml of ionic liquid was weighed and transported into the cell above the bottom clearance. the phenol solution of 300 ppm concentration, represents feed phase, whilst, the naoh solution of 0.5m concentration represents stripping phase. the volume of each phase was 200 ml. figure 4 shows the arrangement of the cell and solutions. the feed and stripping phases were agitated by mechanical stirrers with stainless steel propeller stirrer; 4bladed of 3.5 cm diameter at 200 rpm .whereas magnetic stirrer with a magnetic bar was used to agitate the membrane phase. two samples of (1 ml) were taken from feed and stripping phase every 30 minutes for 5 h. a micropipette type gilson, was used to take the samples. the obtained samples were scanned by uv-vis spectrometer in order to compute the extraction and stripping efficiencies compounds. extraction of phenol from aqueous solutions using bulk ionic liquid membranes 88 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net fig. 4, extraction unit of phenol the performance of bulk liquid membrane was evaluated by computing both the extraction and stripping efficiencies. the concentration of phenolic compound in each phase were measured for this purpose .the calculation of extraction and stripping efficiencies were achieved by using equations 2 and 3,respectively. 100%    o fo c cc e ... (2) 100% 0    f s cc c s ... (3) where: e &s are extraction and stripping efficiency respectively c0 is the initial concentration of phenol in the feed in ppm ,cf is concentration of feed samples after extraction and cs is phenol concentration in stripping samples after extraction. the amount of sodium phenolate in the stripping phase was converted to phenol according to mole balance: c6h5oh + naoh → c6h5ona + h2o phenol sodium phenolate results and discussion 1distribution coefficient of synthesized ionic liquids experimental data of distribution coefficients for phenol is listed in table 2 as a function of ph of feed phase. as can be seen from this table, kd values of the phenol are extremely high under the condition of ph smaller than 7, and then these values drops sharply for ph greater than 7. the characteristic of phenol charge in different ph medium may cause this behaviour. the value of (pka) of phenol in water is 10.0. analytical chemistry calculations indicated that in acidic medium, phenol occurred in molecular form [6].whereas, the anionic portion increases with the increasing of ph of aqueous phase and reaches the half at ph equals the value of pka. for that reason, in acidic conditions it is suitable to consider the interactions among ionic liquid and molecules of the phenol to be in charge of the high distribution coefficients. the molecular dynamic simulations confirmed that ionic liquids are powerfully dissolved by solvents which can form the hydrogen bonding. basically the mechanism of dissolving including the formation of hydrogen bonds with the anions [7].according to this result, the interactions of hydroxyl hydrogen of the phenols with hydrogen bonding of [pf6] − or [bf4] − will be predictable. a portion of these interactions diminished in the case of basic solution as result of the reduction of molecules of phenol. finally a low distribution coefficients observed in the medium of basic solution. as it can be seen from table 2, the distribution coefficients of phenol in the acidic medium obey the following sawsan a.m. mohammed and mohammed saadi hameed -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 89 order: [bf4] − > [ntf2] − > [pf6] − , and this arrangement is caused by the difference in strength of hydrogen bonding between [bf4] − , [ntf2] − or [pf6] − and the phenol. the calculation of chemical quantum [8] showed that effective negative charge of [bf4] − is much stronger than both [ntf2] – and [pf6] − . the hydrogen bonding among [bf4] − and phenols is so stronger that these phenols possess an elevated distribution coefficient. table 2 displays a comparison for the distribution coefficients of the phenols and conventional solvents such as benzene, cyclohexane and dichloromethane .in neutral medium, the distribution coefficients of the conventional solvent are much lower than those of phenol. so, the ionic liquids possess many applications in separation processes of the phenols from wastewater. table 2, distribution coefficients of the phenol between ionic liquids and aqueous solution as a function of ph of aqueous phase (22±1 0 c) ionic liquid distribution coefficient ( kd ) ph= 2.93 ph= 6.04 ph= 8.35 1 [bmim][ntf2] 35.3 35.1 0.47 2 [hmim][ntf2] 33.4 33.1 0.39 3 [omim][ntf2] 30.2 30 0.35 4 [bmim][pf6] 33.4 33 0.34 5 [hmim][pf6] 32.2 31.9 0.45 6 [bmpyr][ntf2] 29.5 29.1 0.43 7 [omim][bf4] 158 _ _ 8 benzene _ 6.2 _ 9 cyclohexane _ 3.5 _ 10 dichloromethane _ 8.1 _ tables 2 displays a comparison for the distribution coefficients of the 4nitrophenol and conventional solvents such as benzene, cyclohexane and dichloromethane .in neutral medium, the distribution coefficients of the conventional solvent are much lower than those of ionic liquids. so, the ionic liquids possess many applications in separation processes of the phenols from waste water. depending on the results that have been obtained by measuring the distribution coefficient of different ionic liquids, the following ionic liquids were chosen as membrane solvents in this study: [bmim][ntf2],[hmim][ntf2],[omim][ ntf2],[bmim][pf6],[hmim][pf6], [bmpyr][ntf2]and [omim][bf4]. these ionic liquids exhibit a powerful solvation and possess a high distribution coefficient. [omim][bf4] has the highest value of distribution coefficient: 29 at ph≈2.9 for phenol. unfortunately, [omim][bf4] was found to be unsuitable solvent in liquid membrane extraction, because it has a density close to the density of water(1.12 g/cm 3 ), which makes [omim][bf4] mixed with aqueous solution at a slow rotation speed not exceeding 50 rpm. figure 5 shows that [bmim][ntf2] was the best ionic liquid because of its high extraction efficiency, this can be attributed to the high distribution coefficient compared with other ionic liquids as indicated in table 2 as it can be seen from figure 5, extraction efficiency of the ionic liquids follows the order:[bmim][ntf2] > [hmim][ntf2] > [omim][ntf2]]; [bmim][pf6] > [hmim][pf6] .it can concluded from these results that, the increasing of the length of alkyl chain on the cation of the ionic liquids, leads to decrease the extraction efficiency. in addition to this, the efficiency values are elevated in the case of using [ntf2] − anion compared with that of [pf6] − anion. extraction of phenol from aqueous solutions using bulk ionic liquid membranes 90 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net the current work is in agreement with the work done by y.s.ng [8], in that the hydrophobic behaviour of ionic liquids was not effective in t deciding the phenol extraction efficiency. the work of fan[9] confirmed that phenol extraction efficiency increased with the increasing of hydrophobic part in ionic liquid as a result of increasing strength of hydrogen bond. the results of present work can be clarified according to the einsteinstokes equation: : rc kt d   ... (4) where d is the diffusion coefficient, k is the boltzmann’s constant, t is absolute temperature, c is a constant (4 to 6), η is viscosity of liquid and r is effective hydrodynamic or stokes radius. according to this equation, the diffusion coefficient (d) is inversely proportional to the viscosity of the liquid, while the viscosity of ionic liquid increases with increasing chain length. for instance, the viscosity of [bmim][ntf2] , [hmim][ntf2] and [omim][ntf2] are: 0.03144, 0.05964 and 0.09104 pa.s at 20.2 ºc respectively. the decreasing of diffusion coefficient caused a drop in the extraction efficiency which is mainly dependent on diffusion process. on the other side of apparatus where stripping processes took place, figure 6 indicated that the stripping process is done effectively by applying naoh solution. although different values of stripping efficiencies were obtained, [bmim][ntf2] possessed the greater efficiency compared with other ionic liquids. this result was due to its lower viscosity compared with other ionic liquids. the viscosity of ionic liquid play a vital role in overriding stripping rate because of the viscosity membrane diminishes the membrane thickness. fig.5, extraction efficiency of phenol by bulk ionic liquid membrane (feed phase ph: ≈ 4.6; feed concentration: 300 ppm; naoh concentration: 0.5 m; aqueous and membrane stirring speed=100 rpm; temperature=22 o c). fig. 6, stripping efficiency of phenol by bulk ionic liquid membrane (feed phase ph: ≈ 4.6; feed concentration: 300 ppm; naoh concentration: 0.5 m; aqueous and membrane stirring speed=100 rpm; temperature=22 o c) 2factors affecting the performance of the best ionic liquid membrane ([bmim][ntf2]) a. aqueous stirring speed of feed phase and stripping phase figures 7 and 8 confirm that the increase of aqueous stirring speed from 75 to 125 rpm increases the extraction and stripping efficiency. higher aqueous stirring speed results in increasing of extraction and stripping rate through supplying a better mixing and reducing the boundary layer sawsan a.m. mohammed and mohammed saadi hameed -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 91 thickness between the membrane phase and aqueous phase. in the present work, the value of aqueous stirring speed (75-125 rpm) was lower than that used in other previous studies (100-300 rpm) such as [8,10]. in spite of this difference in rotation speed, the obtained extraction efficiencies were satisfactory. b. membrane stirring speed through figure 9 and 10, it can be concluded that the speed of rotation of membrane affected the extraction and stripping efficiency of the membrane, but to a lesser extent compared with the effect of variation of aqueous stirring speed. the existence of membrane stirring enhanced the performance of liquid membrane, while in the case of the absence of membrane agitation; it was found that the extraction and stripping efficiencies were affected significantly. fig. 7, effect of aqueous stirring speed on the extraction efficiency of phenol by bulk ionic liquid membrane (feed phase ph: ≈ 4.6; feed concentration: 300 ppm; naoh concentration: 0.5 m; membrane stirring speed=100 rpm; temperature=22 o c however, this enhancement became lower as the membrane stirring speed was increased from 100 to 130 rpm, where the extraction and stripping efficiencies were very close. fig. 8, effect of aqueous stirring speed on the stripping efficiency of phenol by bulk ionic liquid membrane (feed phase ph: ≈ 4.6; feed concentration: 300 ppm; naoh concentration: 0.5 m; membrane stirring speed=100 rpm; temperature=22 o c). fig. 9, effect of membrane stirring speed on the extraction efficiency of phenol by bulk ionic liquid membrane (feed phase ph: ≈ 4.6; feed concentration: 300 ppm; naoh concentration: 0.5 m; aqueous stirring speed=100 rpm; temperature=22 o c). extraction of phenol from aqueous solutions using bulk ionic liquid membranes 92 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net fig. 10, effect of membrane stirring speed on the stripping efficiency of phenol by bulk ionic liquid membrane (feed phase ph: ≈ 4.6; feed concentration: 300 ppm; naoh concentration: 0.5 m; aqueous stirring speed=100 rpm; temperature=22 o c). c. feed concentration figure 11 and 12 indicate that the feed concentration has less influence on the extraction efficiency. the final extraction efficiency remained approximately constant for all phenols as the feed concentration was increased from 100 to 1000 ppm. this may be resulted from the high dissolving capacity or high distribution coefficient of phenol in the ionic liquids. furthermore, the simultaneous stripping process in liquid membrane system also prolonged the time required for membrane saturation. a similar trend was observed for the stripping efficiency as the feed concentration was increased from100 to 1000 ppm, and as shown in figure 12. this manner can be attributed to that the stripping rate was fast enough at low feed concentrations(100-1000) to avoid the built-up of phenol concentration in the membranestripping interface due to the low available amount of phenol in the membrane phase. in the work of lakshmi, et al., 2013, higher feed concentration (2000-6000 ppm) was used. they observed higher stripping efficiency due to accumulation of phenol in membrane. with the aid of magnetic stirring in the membrane phase, significant amount of accumulated phenol in the membrane phase was distributed to a further distance in the stripping compartment. fig. 11, extraction efficiency of phenol by bulk ionic liquid membrane at different feed concentrations (feed phase ph: ≈4.6; naoh concentration: 0.5 m; aqueous and membrane stirring speed=100 rpm; temperature=22 0 c). fig. 12, stripping efficiency of phenol by bulk ionic liquid membrane at different feed concentrations (feed phase ph: ≈4.6; naoh concentration: 0.5 m; aqueous and membrane stirring speed=100 rpm; temperature=22 0 c). sawsan a.m. mohammed and mohammed saadi hameed -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 93 this eventually increased the effective contact area between membrane-stripping interface. thus, the stripping rate and efficiency were increased within increasing the feed concentration from 2000 to 6000 ppm. fig. 13, extraction efficiency of phenol by bulk ionic liquid membrane at different naoh concentrations (feed phase ph: ≈4.6; feed concentration: 300 ppm; aqueous and membrane stirring speed=100 rpm; temperature=22 0 c). d. naoh concentration figure 13 clarifies that the concentration of naoh has small effect on the extraction efficiency of bulk ionic liquid membrane. final extraction efficiency remained approximately unchanged for naoh concentration range of 0 0.5 m. figure 14 confirms that the variation of naoh concentration had significant influence on the stripping efficiency of the system. when the concentration exceeded the value of 0.05, the extraction efficiency approximately remained the same. hypothetically, after the diffusion process, phenol reacts with naoh in the stripping phase to procedure sodium phenolate, and the activity of molecular phenol in the stripping phase is repressed. in other words, the activity of unreacted molecular phenol delayed the stripping process by reducing the concentration gradient between the membrane and stripping phase under low naoh concentration, thus dropping the stripping rate and efficiency. this is supported by the works of lakshmi , ng[8,10] and li[11]. fig. 14, stripping efficiency of phenol by bulk ionic liquid membrane at different naoh concentrations (feed phase ph: ≈4.6; feed concentration: 300 ppm; aqueous and membrane stirring speed=100 rpm; temperature=22 0 c). e. feed phase ph figure 15 shows that the extraction efficiency of phenol by [bmim][ntf2] based liquid membrane remains approximately constant when the feed phase ph is held below the value of pka. however, there was a drastic reduction in the extraction efficiency when ph of feed solution approached the value of pka or became greater than the value of pka. for example, the extraction efficiency of phenol remains approximately constant at 90% when the feed phase ph is held below 6.5 and becomes 79.69 and 4.30 % at ph equals 9.25 and 11.32 respectively. the results of the current study appear to be consistent with the work of fan[1] and khachatryan[12]. extraction of phenol from aqueous solutions using bulk ionic liquid membranes 94 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net the reduction in the efficiency of extraction of phenol is a consequence of the formation of hydrogen bonding between the molecular phenols with the anion of the ionic liquid. the weak bonding results in lowering the value of distribution coefficient (kd), furthermore all phenols that were used in the present work are weak acids, and ionized as phenolate ions under high ph condition (≥ pka value).this fact of possessing phenols a lower distribution coefficient at high value ph leads to reduce the extraction efficiency of phenols. besides that, figure 15 shows that the stripping efficiency is less affected by the feed phase ph, for example the stripping efficiency of phenol is recorded in the range of 75.74– 72.43 % for ph range of 4.05– 11.32. the low extraction efficiency for phenolate ion by [bmim][ntf2] guaranteed a stable one way transport process was achieved in high ph stripping phase , so that the stripping efficiency was not affected by increasing of ph value. fig. 15, effect of feed phase ph on the performance of bulk ionic liquid membrane of phenol (feed concentration: 300 ppm; aqueous and membrane stirring speed=100 rpm; temperature=22 0 c) f. the ratio of feed solution to ionic liquid in this study two ratios of feed solution to [bmim][ntf2] ionic liquid were used (200 ml feed: 80 ml ionic liquid and 400 ml feed: 80 ml ionic liquid). figure 16 and 17 display the effect of phase volume ratios on values of extraction and stripping efficiency. it can be seen that values of extraction and stripping efficiency decrease slightly with increasing phase volume ratio from 200 ml feed: 80 ml ionic liquid to 400 ml feed: 80 ml ionic liquid. this low reduction in both extraction and stripping efficiency due to the powerful solvation ability of ionic liquid when used as a solvent in liquid membrane. the same behaviour was observed by fan, et al., 2008, who extracted phenol from the aqueous solution by [bmim][pf6] and found that the distribution coefficient of phenol changed slightly when the ratio of aqueous solution to ionic liquid increased from 1: 1 to 5: 1. therefore, the extraction and stripping efficiency will not be affected because it mainly depends on the distribution coefficient. g. extraction temperature to examine the effect of temperature on the extraction and stripping efficiency of the phenol, the extraction experiments of phenol by [bmim][ntf2] were carried out at 22, 30, 40 and 50 ºc. figures18 and 19 show the temperature dependence of the extraction and stripping efficiency of the phenols and these efficiencies are enhanced by the increase in temperature. this enhancement in efficiencies can be interpreted by the improving of the diffusion of species which transported through liquid membrane, due to the reduction of the membrane viscosity. sawsan a.m. mohammed and mohammed saadi hameed -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 95 it was previously demonstrated that diffusion coefficient (d) is inversely proportional to the viscosity of the liquid and the increase of diffusion coefficient lead to rising of both extraction and stripping efficiencies which are mainly dependent on diffusion process. fig. 16, extraction efficiency of phenol by bulk ionic liquid membrane at different phase volume ratios (feed phase ph: ≈6.5; feed concentration: 300 ppm; naoh concentration: 0.5 m; aqueous and membrane stirring speed=100 rpm; temperature=22 0 c). fig. 17, stripping efficiency of phenol by bulk ionic liquid membrane at different phase volume ratios (feed phase ph: ≈6.5; feed concentration: 300 ppm; naoh concentration: 0.5 m; aqueous and membrane stirring speed=100 rpm; temperature=22 0 c). fig. 18, extraction efficiency of phenol by bulk ionic liquid membrane at different temperatures (feed phase ph: ≈4.6; feed concentration: 300 ppm; naoh concentration: 0.5 m; aqueous and membrane stirring speed=100 rpm). fig. 19, stripping efficiency of phenol by bulk ionic liquid membrane at different temperatures (feed phase ph: ≈4.6 ; feed concentration: 300 ppm; naoh concentration: 0.5 m; aqueous and membrane stirring speed=100 rpm) conclusions 1through studying of the distribution ratios of phenol between ionic liquids and aqueous solution at different ph values, the results indicated that distribution ratios of phenol were highly affected by ph extraction of phenol from aqueous solutions using bulk ionic liquid membranes 96 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net of aqueous phase and nature of ionic liquids. the results confirmed that ionic liquids have potential application in practical liquid–liquid extraction process of phenol from aqueous solution due to having higher distribution ratios compared with organic solvents. 2through experiments that were conducted to choose the best ionic liquid, the results showed that [bmim][ntf2] gave the greatest phenol extraction and stripping efficiencies compared to other used ionic liquid. also, it was found that the hydrophobicity of the ionic liquids did not have significant effect on the results of extraction and stripping efficiencies. 3the performance of the best ionic liquid ([bmim][ntf2] ) as bulk liquid membrane was improved by increasing both aqueous and membrane stirring speeds. extraction and stripping efficiencies remained unaffected when feed concentration was increased from 100 to 1000 ppm. 4the variation of naoh concentration had no effect on the extraction efficiency of bulk ionic liquid membrane and on the contrary it had significant influence on the stripping efficiency. 5the feed ph did not affect the extraction efficiency of phenols for ph less than pka. however, the extraction efficiency was reduced strongly when ph of feed solution ≥ pka. in contrast, the stripping efficiency was not affected by increasing the ph value. 6both extraction and stripping efficiencies decreased slightly with increasing phase volume ratio from 200 ml feed: 80 ml ionic liquid to 400 ml feed: 80 ml ionic liquid. acknowledgment the authors express their gratitude to ministry of oil-middle company –aldora refinery for financial support of this work.special thanks are also due to the technical staff of chemical engineering department, university of baghdad for this support and assistance. references 1san rom´an, m., bringas, e. & ortiz, i., 2009. liquid membrane technology: fundamentals and review of its applications. j chem technol biotechnol, volume 85, p. 2-10. 2petkovic, m., seddon, k. r., rebelo, l. p. n. & pereira, c. s., 2011. ionic liquids: a pathway to environmental acceptability. chem. soc. rev., volume 40, p. 1383– 1403. 3noble, r. d. & stern, s. a., 1995. membrane separation technology principles and applications. amsterdam,: elsevier. 4huddleston, j. g. et al., 2001. characterization and comparison of hydrophilic and hydrophobic room temperature ionic liquids incorporating the imidazolium cation. green chemistry, volume 3, p. 156–164. 5shukla, m., srivastava, n. & saha, s., 2011. interactions and transitions in imidazolium cation based ionic liquids. in: s. t. handy, ed. ionic liquids – classes and properties. janeza trdine 9, 51000 rijeka, croatia: intech, p. 153-170. 6laitimen, h. & harris, w., 1975. chemical analysis. 2nd ed. new york: mcgraw-hill. 7hanke, c., atamas, n. & lyndenbell, r., 2002. solvation of small molecules in imidazolium ionic liquids: a simulation study. green. chem., volume 4, p. 107–111. sawsan a.m. mohammed and mohammed saadi hameed -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 97 8ng, y. s., jayakumar, n. & hashim, m., 2011. behavior of hydrophobic ionic liquids as liquid membranes on phenol removal:experimental study and optimization. desalination, volume 278, p. 250– 258. 9fan, j. et al., 2008. solvent extraction of selected endocrinedisrupting phenols using ionic liquids. separation and purification technology , volume 61, p. 324– 331. 10lakshmi, a., s.sindhu & s.venkatesan, 2013. performance of ionic liquid as bulk liquid membrane for chlorophenol removal. int.j.chemtech res., 5(3), p. 1129-1137. 11li, n. n., fane, a. g., ho, w. s. w. & matsuura, t., 2008. advanced membrane technology and applications. new jersey: john wiley & sons, inc.. 12tsunekawa, h. et al., 2003. solvation and ion association studies of libf4propylenecarbonate and libf4propylenecarbonate-trimethyl phosphate solutions. j. phys. chem., volume b 107 , p. 10962– 10966 available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol. 24 no.1 (march 2023) 27 – 31 eissn: 2618-0707, pissn: 1997-4884 *corresponding author: name: ammar s. abbas, email: ammarabbas@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. measurement and analysis of bubble size distribution in the electrochemical stirred tank reactor raghad s. mahmood a, alanood a. alsarayreh b, and ammar s. abbas a, * a chemical engineering department, college of engineering, university of baghdad, iraq b chemical engineering department, faculty of engineering, mutah university, p.o. box 7, karak 61710, jordan abstract the dimensions of bubbles were measured in a stirrer tank electrochemical reactor, where the analysis of the bubble size distribution has a substantial impact on the flow dynamics. the high-speed camera and image processing methods were used to obtain a reliable photo. the influence of varied air flow rates (0.3; 0.5; 1 l/min) on bsd was thoroughly investigated. two types of distributors (cubic and circular) were examined, and the impact of various airflow rates on bsd was investigated in detail. the results showed that the bubbles for the two distributors were between 0.5 and 4.5 mm. for both distributors at each airflow, the sauter mean diameter for the bubbles was calculated. according to the results, as the flow rate raised, the bubble size for cubic distributors increased from 2.35 to 2.41 mm and for circular distributors from 2.76 to 2.88 mm. keywords: electrochemical, bubble size distribution, reactor, mean diameter. received on 01/07/2022, received in revised form on 26/08/2022, accepted on 27/08/2022, published on 30/03/2023 https://doi.org/10.31699/ijcpe.2023.1.4 1introduction many industrial processes generate toxic and polluted wastewater that is difficult to degrade and requires costly physical or physic-chemical treatments [1]. one of the most essential and efficient treatment methods is electrooxidation, which has become a viable alternative for wastewater treatment via redox reactions. as a result, the electrochemical reactor (ecr) systems have great interest daily [2, 3]. the continuous stirred tank electrochemical reactor with gas-liquid flow is commonly used in wastewater treatment plants as multiphase reactors. bubble reactors are employed in several process industries because of their simple structure and ease of use [4]. the dispersed aeration is the dominant parameter that enhances oxygen transmission in several applications. the aeration involves the diffusion of air into the liquid in the form of bubbles through small holes of a distributor [5]. the performance of gas-liquid systems is affected by the dispersion of the gas into the reactor. tiny bubbles with a uniform distribution over the equipment's cross section are preferred to increase the interfacial area and enhance transport phenomena [6]. one of the most critical parameters impacting the efficiency of this form of operation is the contact time of air bubbles with the liquid. the contact time depends on the size of the bubble, its terminal velocity, diffuser submergence, and water velocity [7]. the speed of a bubble in a continuous fluid is affected by many physical properties, such as the density, viscosity, and surface tension of both gas and liquid, as well as by outside factors, such as mixing conditions [8]. the bubble size distribution (bsd) is a significant parameter in reactor design and the performance of gasliquid contact [9]. large bubbles prefer to escape quickly at the top surface, whereas tiny bubbles are more likely to reach the side wall and mold depth. also, tiny bubbles increase the gas-liquid interface area, the contact time between the air bubble and the water rises, and the mass transfer process and flow behavior change [10,11]. for optimizing bubble reactor processes, knowing the bsd in the specific system under various operating conditions is crucial. however, the bsd in an industrial bubble reactor is extremely challenging to quantify. in order to analyse the bubble size, various types of laboratory-scale bubble reactors have been used [12]. intrusive and non-intrusive techniques can be used to measure bsd. non-intrusive techniques, such as image analysis of bubble photos, are often favored since they do not impact the reactor's hydrodynamics [13-15]. the high-speed camera captures the bubble images directly, retrieving image features through digital image processing to determine bubble sizes and their distribution [16,17]. the goal of this work is to figure out the bubble size distribution for two types of distributors in a continuous stirred tank electrochemical reactor and figure out the sauter mean diameter for each distributor at different air flow rates. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:ammarabbas@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2023.1.4 r. s. mahmood et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 27 31 28 2experimental work using a camera (nikon d750, 1/20000s), 24 megapixels, and an objective lens (nikon 40x), connected to a high-speed flash source (nicefoto n4). the camera was also connected to the pc (laptop type lenovo legion y530) to analyze the images by computer programming. all parts of the camera were selfassembled and designed. the dimensions of the bubbles were photographed in a glass box with dimensions of (15 cm × 22 cm × 17cm) in length, width, and height, respectively. air bubbles were introduced through the distributor in the test region of the box at the required flow rate. the camera and the flash were operated. images were taken of the bubbles while they were rising throughout the water. these images appeared on the laptop screen and were recorded. images were captured near the box wall nearest the camera, pointing at the reactor's centerline to reduce image distortion. in this situation, the bubbles along the wall are assumed to be typical of those within the box. two types of distributors were tested, cubic (sands and stone; 12 x 25 mm) and circular (sands and stone, plastic; 10.1 x 6.9 x 1.2 cm; hole diameter: 3 mm). each air distributor was photographed at (0.3, 0.5, 1 l/min) air flow rates. several images were captured while the bubbles were rising in the liquid, and then the photos were processed by imagej software [18] to calculate the size of the bubbles. a reference scale was used for calibration, and after that, an 'analysis tool' was used to measure the effective bubble diameter. fig. 1 shows the schematic diagram of the labscale system. the bubble size distribution was characterized by sauter mean diameter (ds). its expression is given by eq. 1 [19]: 3 2 i i s i i n d d n d    (1) where di is the bubble diameter (mm) and ni is the number of bubbles of diameter di. the relative frequency can be determined as the ratio between the number of bubbles in each range and the total number of bubbles. fig. 1. schematic diagram of the lab-scale system 3results and discussion the photographic method was used to determine the size of the bubbles at different air flow rates (0.3; 0.5; 1 l/min). fig. 2, and fig. 3 show the photographed bubbles at 0.3; 0.5; 1 l/min for cubic and circular distributors, respectively. the only clear images in all the photographs are of bubbles near the vessel wall. some bubbles do not have a perfect sphere shape, but an oblate spheroid can be used to approximate it. it can also be observed that the bubble size is not uniform in all images. the imagej program processed the photos, and the sauter mean diameter of the bubble for each distributor was calculated. fig. 4 shows the cubic distributor's bsd. it can be observed from figure 4 at a flow rate of 0.3 l/min that bubbles with diameters ranging from 2 to 2.5 mm have a greater relative frequency when compared to other ranges. furthermore, with approximately 40%, the 2-2.5 mm range was the most dominating. at an airflow rate of 0.5 l/min, bubbles with diameters ranging from 1.5 to 2 mm have a higher relative frequency of 0.37. as a result, the size range between 1.5-2 mm was the most dominating range. figure 4 presents bsd at a flow rate of 1 l/min. bubbles with sizes between 1 and 1.5 mm have a relative frequency of 0.37. the lowest relative frequency was observed between the bubble diameters of 0.5-1, 3-3.5, and 3.5-4 mm. (a) (b) (c) fig. 2. cubic distributor bubbles (a: 0.3l/min; b: 0.5 l/min; c: 1 l/min) r. s. mahmood et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 27 31 29 (a) (b) (c) fig. 3. circular distributor bubbles (a: 0.3 l/min; b: 0.5 l/min; c: l/min) fig. 5 shows bsd for a circular distributor at 0.3, 0.5, and 1 l/min. at air flow rate of 0.3 l/min, fig. 4 indicates that the higher relative frequency was at bubble size from 1.5 to 2 mm range which reached 0.47; thus, the size range between 1.5-2 was the most dominating range. at 0.5 l/min, the same dominant range was observed with a relative frequency of 0.3. in comparison, the lowest relative frequency was in the size range between 4-4.5 mm. figure 4 noted that at 1 l/min, the lowest relative frequency was observed between the bubble diameters of 3.5-4 mm. the most dominant range (approximately 35%) was clearly between 0.5-1 mm. fig. 4. bsd for cubic distributor (0.3 l/min; 0.5 l/min; 1 l/min) table 1 represents the sauter mean diameter (ds) value for the bubbles of cubic and circular distributors calculated from eq. 1. at 0.3 l/min, the cubic distributor bubbles' size was equal to 2.35 mm, which is smaller than the size of the bubbles for the circular distributor (2.76 mm). as the airflow increases, the bubble size of both distributors increases from 2.35 mm to 2.41 mm for the cubic distributor and from 2.76 mm to 3.88 mm for the circular distributor, but the bubble size of the cubic distributor remains smaller than the bubble size of the circular distributor. this increase in the size of the bubbles occurred because the airflow rate directly contributes to the bubble expansion process during bubble formation. the higher the flow rate, the faster the bubble forms, resulting in a larger bubble size. since it is known that the smallest bubble size is the best air distributor thus, the cubic distributor has been selected. fig. 5. bsd for circular distributor (0.3 l/min; 0.5 l/min; 1l/min) table 1. the value of sauter mean diameter for the bubbles of cubic and circular distributor air flow rate (l/min) ds (mm) cubic distributor circular distributor 0.3 2.35 2.76 0.5 2.38 2.98 1 2.41 3.88 4conclusion bsd and the sauter mean diameter for the two-phase continuous stirred tank electrochemical reactor were r. s. mahmood et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 27 31 30 measured photographically. two types of distributors were studied at different air flow rates (0.3; 0.5; 1 l/min). the results show that the highest relative frequency for a cubic distributor at 0.3 l/min was at bubble diameters ranging between 2 to 2.5 mm. in comparison, at 0.5 l/min the bubbles with diameters ranging from 1.5 to 2 mm have a higher relative frequency. the bubble size range between 1-1.5 mm has a higher relative frequency at 1 l/min. for circular distributor, the highest relative frequency ranged between 1.5-2 mm at 0.3 l/min and 0.5 l/min, 0.5-1 mm at 1 l/min. the sauter mean diameter of the bubbles was increased with an increase in the airflow rate for each distributor. still, the cubic distributor has a smaller bubble size than the circular distributor under all conditions. references [1] b. k. körbahti and a. tanyolaç, "modeling of a continuous electrochemical tubular reactor for phenol removal," chem. eng. commun., vol. 190, no. 5–8, pp. 749–762, 2003, https://doi.org/10.1080/00986440302129. [2] f. c. walsh, "electrochemical technology for environmental treatment and clean energy conversion," pure appl. chem., vol. 73, no. 12, pp. 1819–1837, 2001, https://doi.org/10.1351/pac200173121819. [3] r. s. mahmood and a. s. abbas, "validation of a three-parameters hydrodynamic model to describe the non-ideal flow in a continuous stirred tank reactor of the electro-fenton oxidation of organic pollutants in wastewater," j. phys. conf. ser., vol. 1973, no. 1, p. 012092, 2021, http://doi.org/10.1088/17426596/1973/1/012092. [4] h. wang, x. jia, x. wang, z. zhou, j. wen, and j. zhang, "cfd modeling of hydrodynamic characteristics of a gas-liquid two-phase stirred tank," appl. math. model., vol. 38, no. 1, pp. 63–92, 2014, https://doi.org/10.1016/j.apm.2013.05.032. [5] w. h. zhang, x. jiang, and y. m. liu, "a method for recognizing overlapping elliptical bubbles in bubble image," pattern recognit. lett., vol. 33, no. 12, pp. 1543–1548, 2012, https://doi.org/10.1016/j.patrec.2012.03.027. [6] m. polli, m. di stanislao, r. bagatin, e. a. bakr, and m. masi, "bubble size distribution in the sparger region of bubble columns," chem. eng. sci., vol. 57, no. 1, pp. 197–205, 2002, https://doi.org/10.1016/s0009-2509(01)00301-3. [7] d. s. mavinic and j. k. bewtra, "bubble size and contact time in diffused aeration systems," j. water pollut. control fed., vol. 46, no. 9, pp. 2129–2137, 1974. [8] m. s. n. oliveira, a. w. fitch, and x. ni, "a study of bubble velocity and bubble residence time in a gassed oscillatory baffled column effect of oscillation frequency," engineering, vol. 81, no. february, 2003, https://doi.org/10.1205/026387603762878692. [9] s. capela, m. roustan, and a. héduit, "transfer number in fine bubble diffused aeration systems," water sci. technol., vol. 43, no. 11, pp. 145–152, 2001, https://doi.org/10.2166/wst.2001.0677. [10] w. yang, z. luo, n. zhao, and z. zou, "numerical analysis of effect of initial bubble size on captured bubble distribution in steel continuous casting using euler-lagrange approach considering bubble coalescence and breakup weidong," 2020, https://doi.org/10.3390/met10091160. [11] h. j. b. couto, d. g. nunes, r. neumann, and s. c. a. frança, “micro-bubble size distribution measurements by laser diffraction technique,” miner. eng., vol. 22, no. 4, pp. 330–335, 2009, https://doi.org/10.1016/j.mineng.2008.09.006. [12] y. m. lau, k. t. sujatha, m. gaeini, n. g. deen, and j. a. m. kuipers, "experimental study of the bubble size distribution in a pseudo-2d bubble column," chem. eng. sci., vol. 98, pp. 203–211, 2013, https://doi.org/10.1016/j.ces.2013.05.024. [13] d. mesa and p. r. brito-parada, "bubble size distribution in aerated stirred tanks: quantifying the effect of impeller-stator design," chem. eng. res. des., vol. 160, no. 1, pp. 356–369, 2020, https://doi.org/10.1016/j.cherd.2020.05.029. [14] g. g. bellido, m. g. scanlon, j. h. page, and b. hallgrimsson, "the bubble size distribution in wheat flour dough," food res. int., vol. 39, no. 10, pp. 1058–1066, 2006, https://doi.org/10.1016/j.foodres.2006.07.020. [15] t. wang, z. xia, and c. chen, "computational study of bubble coalescence/break-up behaviors and bubble size distribution in a 3-d pressurized bubbling gassolid fluidized bed of geldart a particles," chinese j. chem. eng., vol. 44, pp. 485–496, 2022, https://doi.org/10.1016/j.cjche.2021.03.040. [16] t. xue, x. w. liu, y. x. jin, and b. wu, "bubbles image processing and parameters measurement based on the high-speed photography," seventh int. symp. precis. eng. meas. instrum., vol. 8321, p. 83210t, 2011, https://doi.org/10.1117/12.903860. [17] r. s. mahmood, a. s. abbas, and international scientific conference marshes research center, "internals design of continuous stirred tank electrochemical reactor based on the residence time distribution approach," egypt. j. chem., 2022, http://doi.org/10.21608/ejchem.2022.122976.5502. [18] c. a. schneider, w. s. rasband, and k. w. eliceiri, "nih image to imagej: 25 years of image analysis," nat. methods, vol. 9, no. 7, pp. 671–675, 2012, http://doi.org/10.1038/nmeth.2089. [19] m. senouci-bereksi, f. k. kies, and f. bentahar, "hydrodynamics and bubble size distribution in a stirred reactor," arab. j. sci. eng., vol. 43, no. 11, pp. 5905–5917, 2018, https://doi.org/10.1080/00986440302129. https://www.jstor.org/stable/25038244 https://www.jstor.org/stable/25038244 https://www.jstor.org/stable/25038244 https://www.jstor.org/stable/25038244 r. s. mahmood et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 27 31 31 يع حجم الفقاعات في مفاعل الخزان الكهروكيميائيقياس و تحليل توز ، *1عمار صالح عباس و ، 2، العنود الصرايرة 1رغد ساجد محمود قسم الهندسة الكيمياوية، كلية الهندسة، جامعة بغداد، بغداد، العراق 1 قسم الهندسة الكيمياوية، جامعة موته، االردن 2 الخالصة كبير ي مفاعل كهروكيميائ مستمر، حيث يكون لتحليل توزيع حجم الفقاعة تأثيريتم قياس أبعاد الفقاعات ف على ديناميكيات التدفق. تم استخدام كاميرا عالية السرعة و تقنيات معالجة الصور للحصول على صورة ، 0.3) موثوقة. تم اختبار نوعين من الموزعات )مكعب و دائري(، و ُدرست تأثير معدالت تدفق الهواء المختلفة 4.5لى إ 0.5لتر / دقيقة( على توزيع حجم الفقاعة بالتفصيل. تظهر النتائج أن حجم الفقاعات يتراوح بين 1، يادة ز الموزعين عند كل تدفق هواء. أشارت النتائج إلى ملم للموزعين. تم حساب متوسط قطر الفقاعات لكال ة مم للموزع الدائري عند زياد 2.88إلى 2.76مم للموزع المكعب ومن 2.41إلى 2.35حجم الفقاعة من معدل التدفق. .: الكهروكيميائية، توزيع حجم الفقاعات، المفاعل، متوسط القطردالةالالكلمات available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.23 no.3 (september 2022) 11 – 16 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: ehab borhan yasseen , email: i.yasin1207@coeng.uobaghdad.edu.iq , name: haider a. al-jendeel, email: haider.aljendeel@coeng.uobaghdad.edu.iq, name: mohammed j. al-ani, email: mjav2c@umsystem.edu ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. kinetic study of transesterification reaction of edible oil using heterogenous catalyst ehab borhan yasseen a , haider a. al-jendeel a and mohammed j. al-ani b a chemical engineering department/university of baghdad/baghdad, iraq b chemical and biochemical engineering department, missouri university of science and technology, rolla, mo 65409, usa abstract alpo4 solid acid catalyst was prepared in order to use it in transesterification reaction of edible oil after supporting it with tungsten oxide. the maximum conversion of edible oil was obtained 78.78% at catalyst concentration (5gm.), temperature 70°ϲ, 30/1 methanol/edible oil molar ratio, and time 5hr. the study of kinetics of the transesterification reaction of edible oil indicates that the reaction has an order of 3/2, while the value of activation energy for transesterification reaction is 51.367 kj/mole and frequency factor equal 26219.13(l/ mol.minute). keywords: alpo4, transesterification, edible oil, heterogeneous catalyzed reaction received on 25/02/2022, accepted on 10/05/2022, published on 30/09/2022 https://doi.org/10.31699/ijcpe.2022.3.2 1introduction because of the rising price and depletion of plant energy sources, the energy organization made several studies to find alternative energy production sources [1]. biodiesel is an excellent product of clean, renewable energy produced from renewable biological sources like vegetable oil and fat of animals. biodiesel is defined as fatty acid ester-based on the american standard test of materials (astm) [2]. biodiesel is less dangerous than diesel and friendly to the environment because the less emission of carbon dioxide, sulfur dioxide and outlet combustion does not contain the aromatic compound. it could be used in compression-ignition (diesel) engines [3,4]. biodiesel contains alkyl esters generated from the esterification of free fatty acid (ffas) or the transesterification of triglycerides (tgs), with the low molecular weight of alcohols [5]. biodiesel has the same influx and burning characteristics as petroleum-based diesel. therefore it may be used as a substitute for diesel or, more typically, in fuel blends [6]. pure biodiesel produces around 90% of the energy released by natural fuel. thus the reassembles of engine torsion, and horsepower are the approximate projected engine completion [7]. low-cost feedstocks, predictably, should undergo considerable pre-treatment prior they could be used to make biodiesel [8]. feedstocks made from edible oil and grease waste have been suggested to reduce biodiesel synthesis expenses [9]. amorphous aluminum phosphate can be used as support and catalysts because it is a bifunctional acidbase. it can be used in several processes as catalysis like condensation, cracking, rearrangement, alkylation, isomerization, dehydration and esterification [10, 11, and 12]. studying the kinetics of transesterification reaction were very important in the selection of the most favorable transeterification conditions for maximizing the production of biodiesel , kinetic models may offer different levels of detail and predictive capabilities, as they can take into account mass and heat transfer phenomena, as well as thermodynamic equilibrium. in this research wo3/alpo4 was used for transesterification of edible oil to produced biodiesel and studied the kinetic for transesterification reaction. 2material most materials were obtained from local markets. alpo4: the aluminum phosphate is manufactured locally from [al (no3)3.9h2o and (nh4)2hpo4). table 1 details the chemicals used, along with their characteristics. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:i.yasin1207@coeng.uobaghdad.edu.iq mailto:haider.aljendeel@coeng.uobaghdad.edu.iq mailto:mjav2c@umsystem.edu http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2022.3.2 e. b. yasseen and h. a. al-jendeel / iraqi journal of chemical and petroleum engineering 23,3 (2022) 11 16 12 table 1. chemical compounds and their properties chemicals phase formula density (g/ml) molecularweight (g/gmol) purity (wt%) supplier ammonium meta tungsten solid (nh4)6h2w12o40–x h2o 4.6 2956.2 99.5% china nitric acid liquid hno3 1.51 63.01 72% cdh, india ammonia liquid nh4.xh2o 0.91 17.03 25 % belgium methanol liquid ch3oh 0.792 32.04 99.5% india ethanol liquid c2h5oh 0.789 46.07 99.9 india sodium hydroxide solid naoh 2.13 40 98% india phenolphthalein solid 1.28 318.33 99% france edible oil (sunflower oil) liquid 0.92 876.16 from restaurant 3experimental work alpo4 was synthesized according to xie and yang [13] , the amorphous catalyst was prepared by mixing 30.01 gm of al (no3)3 .9h2o and 9.24 gm of (nh4)2hpo4 with 300 ml deionized water utilizing a stirrer magnetic for thirty minutes to have homogenous mixture, then nitric acid was added drop wise until the mixture reached ph 1.7. ammonia 25wt% solution added dropwise until reach ph 8 to have super saturation mixture and continue stirring for 60 min. these materials stayed on a magnetic stirrer for one hour. then the solution was washed with a double volume of deionized water and filtered under vacuum using filter paper. the catalyst was further dried at 100°c for 24 hours before being calcined at 500°c for three hours. the synthesis of an aluminum phosphate sulfated catalyst involves the inclusion of promoters like tungsten, which would significantly improve edible oil’s esterification process, resulting in increased biodiesel stability and selectivity. the wet-impregnation method added tungsten promoters, first, alpo4 was impregnated with an aqueous sol of ammonium metatungstate ((nh4)6(h2w12o40.nh2o). a dropwise impregnation process was utilized to vary preload percentages of wo3 on it. the generated catalyst was later dried over the night at 100°c and calcinated in air for three hours at 500°c. after preparation of the catalyst different analysis made on the samples 4result and discussion 4.1. characterization of the catalyst fig. 1 shows x-ray diffraction (xrd) of the prepared catalyst , it can be found that the synthesized catalyst has an amorphous phase and this is corresponding to xie and yang [13] , while the prepared catalyst have a surface area of 185.83 m 2 /g and pore volume of 0.645 cm 3 /g fig. 1. x-ray diffraction of alpo4 on the other hand the atomic force microscopy (afm) method was used to find the average particle size. the result showed that the catalyst had an average particle size of 5.865 nm. fig. 2 show the histogram of particle distribution. fig. 2. histogrsm of particle distribution 4.2. effect of reaction time on conversion the effects of reaction time on the conversion of edible oil were studied at different reaction time (0-6 hr) with 35% tungsten promoter at different temperature, 350 rpm, methanol/edible oil ratio (30/1) and 5 wt% of catalyst. e. b. yasseen and h. a. al-jendeel / iraqi journal of chemical and petroleum engineering 23,3 (2022) 11 16 13 it can be shown from fig. 3 that low activity of catalyst at time 1 hr and temperature of 50°c (6.7 % ), while increasing time leads to increase the conversion of edible oil until it reaches equilibrium at time 5 hr (47.32%) , on the other hand the conversion at time 1 hr and temperature 70°c was 37.5% and it reaches equilibrium also at time 5 hr and the conversion in this time was 78.79%. however, increasing the reaction time to 6 hr gives the same conversion at all temperature and this is agreement with the studies of abbas and abbas [14] who pointed to esterification reaction of oleic acid with h2so4 as catalysts, the results of this research found that the best time of esterification reaction was 3 hr. fig. 3. effect of reaction time on edible oil conversion 4.3. effect of methanol/edible oil ratio on conversion one of the most important factors that effect on transesteridication reactions to produced biodiesel was methanol/edible oil ratio. in biodiesel reaction one mole triglyceride (tg) react with three mole of methanol to produce biodiesel as shown in equation 1 [15] . glycerolestersmethanoltgdetriglyceri catalyst  3)( (1) so to increase the conversion of biodiesel produced excess amount of methanol was needed. fig. 4 shows the effect of methanol/edible oil ratio where four amount of ratio were used ( 15/1,20/1,30/1 and 35/1) while other conditions were fixed (temperature 70°c , catalyst amount 5 gram, percentage of wo3 promoters 35% and time of 5 hours). it can be shown from the figure that increasing methanol /oil ratio leads to increase the conversion of edible oil and this is due to increasing the amount of edible oil reacts to produced biodiesel [16]. fig. 4. effect of methanol/oil molar ratio 4.4. kinetic study of transesterification the transesteriication reaction of edible oil consist of three reaction in each reaction one mole of methanol react as shown in equation 2,3 and 4 rcordgediglyceridmethanoltgdetriglyceri 2 ')()(  (2) rcormgidemonoglycermethanoldgediglycerid 2 ')()(  (3) rcorglycerolmethanolmgidemonoglycer 2 ')(  (4) by ignoring the intermediate reaction of monoglyceride and diglyceride the overall reaction can be shown in equation 5 )('33)( 2 glglycerolrcormethanoltgdetriglyceri  (5) the reaction of transesterification carried in a batch reactor and to study the kinetics of the reaction it's important to make an assumption to simplify the mathematical modeling of transesterification 1the reaction of transesterification is not effected from free acid and so no soap present. 2 the reaction do not affect form water (alpo do not affect in the presence of water) so saponification can be negligible. 3the tranesterification reaction is a reversible reaction so using excess amount of methanol make the reaction to go forward (no reverse reaction happen). to find the order of the reaction nth order equation was used as shown in equation 5 [17] tnkcaca nn )1( 1 0 1   (5) by trial and error the most significant order was 1.5 which gave value of r 2 between 0.9728 at temperature 80°c and 0.9927 at temperature 70°c as shown in fig. 5 0 10 20 30 40 50 60 70 80 90 0 1 2 3 4 5 6 7 reaction tim e (hr) c o n v e rs io n [ % ] temp 50°c temp 60°c temp 70°c temp 80°c 0 20 40 60 80 100 10 15 20 25 30 35 m ethanol/edible oil c o n v e rs io n % e. b. yasseen and h. a. al-jendeel / iraqi journal of chemical and petroleum engineering 23,3 (2022) 11 16 14 fig. 5. ca -0.5 vs time at different temperature (50,60,70 and 80°c) with methanol/edible oil (30/1), 35% wo3 and 5gram of alpo4 equilibrium constant can be found from figure 5 by drawing ca -0.5 versus time, and then a straight line will be produce with slope of 0.5. table 2 shows the value of equilibrium constant for forward reaction at different temperature. table 2. equilibrium constant of transesterification reaction temperature (°c) k 50 0.1438 60 0.184 70 0.4416 80 0.1814 to find the activation energy of the reaction arrhenius law will be applied. from arrhenius law (k=k0ee/rt ) by plotting ln k versus 1/t a straight line will be formed with a slope of (-e/r) and intercept k0 , where e is the activation energy , k0 frequency factor and r gas constant as shown in figure 6. fig. 6. ln (k) versus (1/t) it can be concluded figure 6 that the value of activation energy (e) = 51.367 kj/mole while the frequency factor equal 26219.13. the activation energy found in the present work is compared with those reported in the literature by brahmkhatri et al.[18] (44.6 kj/ mol), aranda et al.[19] (42 kj/ mol), sarkara et al.[20] (39.5 kj mol-1) and patel and brahmkhatri .[21] (52.4 kj /mol) 5conclusion alpo4 catalyst was synthesized successfully with amorphous phase and high surface of 185.83 m 2 /g and pore volume of 0.645 cm 3 /gm. the conversion of edible oil obtained was 78.78 % after 5 hr of reaction with 5 gram of catalyst and 30/1 methanol/edible oil molar ratio. the results show that transesterification reaction follow the order of 3/2 and this indicate that the reaction was external diffusion control with activation energy of 5.136 kj/mol. references [1] bohlouli , ali; mahdavian , leila. catalysts used in biodiesel production: a review. biofuels, 2019, 1-14.‏ [2] abbas a.s. and r.n. abbas , "kinetic study and simulation of oleic acid esterification in different type of reactors",2013, iraqi journal of chemical and petroleum engineering, 14(3),35-43. [3] hussain h.k. , h.a.al jendeel , and t.m. naife , production of biodiesel fuel from used vegetable oil, journal of engineering, 17(5), 1371-1377 (2011). [4] ahmedzeki n.s. , alhassani m.h. and al-jandeel h.a. ," heterogeneously catalyzed esterification reaction: experimental and modeling using langmuirhinshelwood approach" ,2013, iraqi journal of chemical and petroleum engineering, 14(4),45-52. [5] freedman, b. e. h. p., e. h. pryde, and t. l. mounts. "variables affecting the yields of fatty esters from transesterified vegetable oils." journal of the american oil chemists society 61.10 (1984): 1638 ‏.1643 [6] sharma, y. c.; singh, b.; upadhyay, s. n. advancements in development and characterization of biodiesel: a review. fuel, 2008, 87.12: 2355-2373.‏ [7] vicente, gemma; martinez, mercedes; aracil, jose. integrated biodiesel production: a comparison of different homogeneous catalysts systems. bioresource technology, 2004, 92.3: 297 ‏.305 [8] bournay, l., casanave, d., delfort, b., hillion, g., & chodorge, j. a. (2005). new heterogeneous process for biodiesel production: a way to improve the quality and the value of the crude glycerin produced by biodiesel plants. catalysis today, 106(1-4), 190-192.‏ [9] gryglewicz, s. (1999). rapeseed oil methyl esters preparation using heterogeneous catalysts. bioresource technology, 70(3), 249-253.‏ [10] grace, w. r.; davison, co grace. sylobead adsorbents for process applications. columbia, md, 2002. [11] chen, h., peng, b., wang, d., & wang, j. (2007). biodiesel production by the transesterification of cottonseed oil by solid acid catalysts. frontiers of chemical engineering in china, 1(1), 11-15. y = 0.2208x + 1.0132 r 2 = 0.9907 y = 0.0907x + 1.0479 r 2 = 0.9728 y = 0.0719x + 1.0274 r 2 = 0.9864 y = 0.092x + 1.0407 r 2 = 0.9774 0 0.5 1 1.5 2 2.5 0 1 2 3 4 5 6 time (hr) c a -0 .5 temp 50°c temp 60°c temp 70°c temp 80°c y = -6178.4x + 17.082 -2.5 -2 -1.5 -1 -0.5 0 0.00288 0.00292 0.00296 0.003 0.00304 0.00308 0.00312 1/t ln k https://www.tandfonline.com/doi/abs/10.1080/17597269.2018.1558836 https://www.tandfonline.com/doi/abs/10.1080/17597269.2018.1558836 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/309 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/309 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/309 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/309 https://www.researchgate.net/profile/hussein-hussein-29/publication/325069968_production_of_biodiesel_fuel_from_used_vegetable_oil_production_of_biodiesel_fuel_from_used_vegetable_oil/links/5af4a4f0a6fdcc0c030af6fd/production-of-biodiesel-fuel-from-used-vegetable-oil-production-of-biodiesel-fuel-from-used-vegetable-oil.pdf https://www.researchgate.net/profile/hussein-hussein-29/publication/325069968_production_of_biodiesel_fuel_from_used_vegetable_oil_production_of_biodiesel_fuel_from_used_vegetable_oil/links/5af4a4f0a6fdcc0c030af6fd/production-of-biodiesel-fuel-from-used-vegetable-oil-production-of-biodiesel-fuel-from-used-vegetable-oil.pdf https://www.researchgate.net/profile/hussein-hussein-29/publication/325069968_production_of_biodiesel_fuel_from_used_vegetable_oil_production_of_biodiesel_fuel_from_used_vegetable_oil/links/5af4a4f0a6fdcc0c030af6fd/production-of-biodiesel-fuel-from-used-vegetable-oil-production-of-biodiesel-fuel-from-used-vegetable-oil.pdf https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/325 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/325 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/325 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/325 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/325 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/325 https://link.springer.com/article/10.1007/bf02541649 https://link.springer.com/article/10.1007/bf02541649 https://link.springer.com/article/10.1007/bf02541649 https://link.springer.com/article/10.1007/bf02541649 https://link.springer.com/article/10.1007/bf02541649 https://www.sciencedirect.com/science/article/pii/s001623610800029x https://www.sciencedirect.com/science/article/pii/s001623610800029x https://www.sciencedirect.com/science/article/pii/s001623610800029x https://www.sciencedirect.com/science/article/pii/s096085240300230x https://www.sciencedirect.com/science/article/pii/s096085240300230x https://www.sciencedirect.com/science/article/pii/s096085240300230x https://www.sciencedirect.com/science/article/pii/s096085240300230x https://www.sciencedirect.com/science/article/pii/s096085240300230x https://www.sciencedirect.com/science/article/pii/s0920586105005043 https://www.sciencedirect.com/science/article/pii/s0920586105005043 https://www.sciencedirect.com/science/article/pii/s0920586105005043 https://www.sciencedirect.com/science/article/pii/s0920586105005043 https://www.sciencedirect.com/science/article/pii/s0920586105005043 https://www.sciencedirect.com/science/article/pii/s0960852499000425 https://www.sciencedirect.com/science/article/pii/s0960852499000425 https://www.sciencedirect.com/science/article/pii/s0960852499000425 https://link.springer.com/article/10.1007/s11705-007-0003-y https://link.springer.com/article/10.1007/s11705-007-0003-y https://link.springer.com/article/10.1007/s11705-007-0003-y https://link.springer.com/article/10.1007/s11705-007-0003-y e. b. yasseen and h. a. al-jendeel / iraqi journal of chemical and petroleum engineering 23,3 (2022) 11 16 15 [12] jitputti, j., kitiyanan, b., rangsunvigit, p., bunyakiat, k., attanatho, l., & jenvanitpanjakul, p. (2006). transesterification of crude palm kernel oil and crude coconut oil by different solid catalysts. chemical engineering journal, 116(1), 61 ‏.66 [13] xie w. and yang d. (2012) . transesterification of soybean oil over wo3 supported on alpo4 as a solid acid catalyst. bioresource technology 119 , 60– 65 [14] abbas a.s. and abbas s. m., (2013), kinetic study and simulation of oleic acid esterification in different type of reactors, iraqi journal of chemical and petroleum engineering vol.14 no.2 , 1320. [15] sreeprasanth, p. s., srivastava, r., srinivas, d., & ratnasamy, p. (2006). hydrophobic, solid acid catalysts for production of biofuels and lubricants. applied catalysis a: general, 314(2), 148 ‏.159 [16] s. r kirumakki, n. nagaraju, k.v. chary,s. narayanan , kinetics of esterification of aromatic carboxylic acids over zeolites hβ and hzsm5 using dimethyl carbonate applied catalysis a: general, ‏.(2003) 248,161-167 ,2003 [17] levenspiel o.,"chemical reaction engineering",3 rd edition, john wiley and sons, 1999. [18] brahmkhatri, v.; patel, a.; tungstophosphoric acid anchored to sba15: an efficient, environmentally benign reusable catalysts for biodiesel production by esterification of free fatty acids, appl. catal., a 2011, 403, 161 [19] aranda, d. a. g.; santos, r. t. p.; neyda, c. o.; tapanes, a. l. d.; ramos, o. a. c.; acid-catalyzed homogeneous esterification reaction for biodiesel production from palm fatty acids catal. lett. 2008, 122, 20. [20] sarkar a., ghosh s.k., pramanik p., 2010. investigation of the catalytic efficiency of a new mesoporous catalyst sno2/wo3 towards oleic acid esterification. j. mol. catal. a: chem., 327, 73–79. doi: 10.1016/j.molcata.2010.05.015. [21] patel, a.; brahmkhatri, v.; kinetic study of oleic acid esterification over 12-tungstophosphoric acid catalyst anchored to different mesoporous silica supportsfuel process. tecnhol. 2013, 113, 141. https://www.sciencedirect.com/science/article/pii/s1385894705004122 https://www.sciencedirect.com/science/article/pii/s1385894705004122 https://www.sciencedirect.com/science/article/pii/s1385894705004122 https://www.sciencedirect.com/science/article/pii/s1385894705004122 https://www.sciencedirect.com/science/article/pii/s1385894705004122 https://www.sciencedirect.com/science/article/pii/s1385894705004122 https://www.sciencedirect.com/science/article/pii/s096085241200867x https://www.sciencedirect.com/science/article/pii/s096085241200867x https://www.sciencedirect.com/science/article/pii/s096085241200867x https://www.sciencedirect.com/science/article/pii/s096085241200867x https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/309 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/309 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/309 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/309 https://www.sciencedirect.com/science/article/pii/s0926860x06006089 https://www.sciencedirect.com/science/article/pii/s0926860x06006089 https://www.sciencedirect.com/science/article/pii/s0926860x06006089 https://www.sciencedirect.com/science/article/pii/s0926860x06006089 https://www.sciencedirect.com/science/article/pii/s0926860x06006089 https://www.sciencedirect.com/science/article/pii/s0926860x03001522 https://www.sciencedirect.com/science/article/pii/s0926860x03001522 https://www.sciencedirect.com/science/article/pii/s0926860x03001522 https://www.sciencedirect.com/science/article/pii/s0926860x03001522 https://www.sciencedirect.com/science/article/pii/s0926860x03001522 https://books.google.com/books?hl=en&lr=&id=vw48eaaaqbaj&oi=fnd&pg=pp1&dq=%5b17%5d%09levenspiel+o.,%22chemical+reaction+engineering%22,3rd+edition,+john+wiley+and+sons,+1999.&ots=5x10iq8r2y&sig=v_lk1czvxye2ol3leup7e3uzbj8 https://books.google.com/books?hl=en&lr=&id=vw48eaaaqbaj&oi=fnd&pg=pp1&dq=%5b17%5d%09levenspiel+o.,%22chemical+reaction+engineering%22,3rd+edition,+john+wiley+and+sons,+1999.&ots=5x10iq8r2y&sig=v_lk1czvxye2ol3leup7e3uzbj8 https://www.sciencedirect.com/science/article/pii/s0926860x11003747 https://www.sciencedirect.com/science/article/pii/s0926860x11003747 https://www.sciencedirect.com/science/article/pii/s0926860x11003747 https://www.sciencedirect.com/science/article/pii/s0926860x11003747 https://www.sciencedirect.com/science/article/pii/s0926860x11003747 https://link.springer.com/article/10.1007/s10562-007-9318-z https://link.springer.com/article/10.1007/s10562-007-9318-z https://link.springer.com/article/10.1007/s10562-007-9318-z https://link.springer.com/article/10.1007/s10562-007-9318-z https://link.springer.com/article/10.1007/s10562-007-9318-z https://www.sciencedirect.com/science/article/pii/s138111691000230x https://www.sciencedirect.com/science/article/pii/s138111691000230x https://www.sciencedirect.com/science/article/pii/s138111691000230x https://www.sciencedirect.com/science/article/pii/s138111691000230x https://www.sciencedirect.com/science/article/pii/s138111691000230x https://www.sciencedirect.com/science/article/pii/s0378382013001264 https://www.sciencedirect.com/science/article/pii/s0378382013001264 https://www.sciencedirect.com/science/article/pii/s0378382013001264 https://www.sciencedirect.com/science/article/pii/s0378382013001264 e. b. yasseen and h. a. al-jendeel / iraqi journal of chemical and petroleum engineering 23,3 (2022) 11 16 16 غير متجانسدراسة حركية تفاعل االسترة للزيوت المستخدمة باستعمال عامل مساعد 2و محمد جابر العاني 1 و حيدر عبد الكريم رشيد 1 ايهاب برهان ياسين جامعة بغداد/كلية الهندسة 1 االمريكية المتحدة الواليات ، mo 65409 ، روال ، والتكنولوجيا للعلوم ميسوري جامعة ، ةاالحيائية والكيميائية الكيميائية الهندسة قسم 2 الخالصة مي اجيل تعياعات االسيترة لل ييوت المسيتعدمة بعيدة alpo4تم تحضير العامل المساعد الحامضي الليل % عنيد تركيي 78,78عملية تحميل العامل المساعد باوكسيد التنكست . ا اعلى تحول تم الحلول عليه هيو سيييا. ا دراسييية 5و مييي 30/1م , نسيييبة الميويييانول/ ال ييييت المسيييتعمل °70غيييم , درجييية حيييرارة 5عاميييل مسييياعد كيليو 51,367و طاقية التنيييط هي 3/2حركية تعاعل االسيترة لل ييوت المسيتعدمة تبيي ا درجية التعاعيل هي .لتر/مول. دقيقة 26219,13د يساوي جول/مول ومعامل ترد الكلمات الدالة : استرة , يت مستعدم, تعاعات العوامل المساعدة الغير متجانسة available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.23 no.2 (june 2022) 35 – 42 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: amel habeeb assi, email: amel@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. geological considerations related to casing setting depth selection and design of iraqi oil wells (case study) amel habeeb assi petroleum engineering department, college of engineering, university of baghdad, baghdad, iraq abstract well integrity is a vital feature that should be upheld into the lifespan of the well, and one constituent of which casing, n ecessity to be capable to endure all the interior and outside loads. the casing, through its two basic essentials: casing design and casing depth adjustment, are fundamental to a unique wellbore that plays an important role in well integrity. casing set depths are determ ined based on fracturing pressure and pore pressure in the well and can usually be obtained from well-specific information. based on the analyzes using the improved techniques in this study, the following special proposition can be projected: the selection of the first class and materials must be done correctly and accurately in accordance with the depth of casing preparation and the strategy in the considered field that must be taken into account definitely in the drilling and completion period, nevertheless corresponding ly in production and upkeep, conversion to an injection well or the opposite, the plug in addition to the closing stage. features that control the depth of the casing seat have been studied, which consist of fracture gradient, pore pressure with other issues are the s urviving lithology's of rocks. subsequently defining the casing seat can be sustained with an investigation of the determination of the suitable drilling fluid. according to the consequences of the fracture pressure and pore pressure investigation and the findings of casing setting depth by means of the bottom-up technique, the consequences are gotten to each casing for the 4 studied wells. reference point designed from the rotating table rt. for well a, the conductor casing depth is 47m, the casing surface depth is 533m , the intermediate casing setting depth is 1882 m. finally, for the production casing depth is 3441 m. compared to the collapse pressure method, it was found that the bottom-up method gave results that are close and similar to the real results. the results of other wells are included in the search consequences keywords: casing, formation, design oil well, setting depth, formation pressure received on 08/03/2022, accepted on 30/04/2022, published on 30/06/2022 https://doi.org/10.31699/ijcpe.2022.2.5 1introduction the first strategic duty in developing a well plan is to choose the depths to which the casing is to be installed and fixed. the drilling engineer must take into account geological conditions for example, fracture gradients, formation pressures, and other well problems, as well as the company's plan [1]. the results of the program should allow the well to be drilled safely without the need to build a "steel monument" to the casing chains. inappropriately, numerous well strategies provide significant thoughts to the real pipe project, with that, just give a quick attention to the depth of tube adjustment [2]. it cannot be exaggerated if it is said and emphasized the importance of choosing the appropriate depths to adjust the casing. a basic detailed drilling application with initial information of the geological conditions in a part can help in organizing where to set the casing strings to ensure that drilling can proceed with minimal effort, as will be explained in detail in this research [3]. the choice of casing string depth of adjustment depends on the fracture gradient values of the well as well as pore formation pressure and geological factors [4]. well integrity is a vital feature that should be upheld into the lifespan of the well, and one constituent of which casing, necessity to be capable to endure all the interior and outside loads. casing program design includes assembling depth settings, casing ranks, and sizes that allow for secure drilling, and well completion in order to prepare for required production [5]. a variety of casing string and their respective location depths are constructed according to geologic conditions and the fresh aquifers they contain. casing setting depth means founded from the seat sector casing depending on the fractures gradient and pore pressure information commencing to the offset wells [6]. assortment of the casing string sizes is usually well-ordered by three main issues which are: (1) production tubing string size, (2) the number of casing strings essential for reaching the ultimate depth, and (3) the other drilling circumstances and geological aspects [7]. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:amel@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2022.2.5 a. h. assi / iraqi journal of chemical and petroleum engineering 23,2 (2022) 35 42 36 then the number of casing strings necessary to include the hole is released, their particular setting depths and its outside diameters, steel grade, the nominal weight, and couplings of each of these strings necessity to be designated. the existing casing installed in some wells depends only on the formation of the drill weight statement mainly without reference to fracture pressure and pore pressure. then, during production, the casing disappointment was revealed. [8]. this research aims to find the fastest and most accurate ways to determine the depth of fixing casings and compare them with what is available through the study of four wells in one of the fields in southern iraq. 2methodology 2.1. bottom up method aimed at the casing setting depth purpose, the fracture gradient and pore pressure are typically termed in pound per gallon(ppg) as shown in fig. 1. [9] fig. 1. fracture pressure with pore pressure values apposite depth [9] the eaton equation, equation 1is used for estimating the fracture gradient: f= s/d* α+(1α) * p/d (1) where: f = fracture gradient, psi/ft. d = depth, m s = overburden stress, psi p = bottom hole static pressure, psi α = v / (1-v), α that diverges between 0.3 and 0.6. v = poisson’s ratio, dimensionless .the thick lines in fig. 1 are not a safety aspect; thus, the first stage of casing preparation depth design, the safety factor should be acceptable. 0.3 ppg. is added as a safety factor for fracture gradient and pore pressure as in fig. 2. the safety factor should be complementary to the formation pressure to maintaining the wellbore pressure between the supreme value which does not principal to fracture of the formation and the pressure of the fluid within the formations, since the pressure of the wellbore surpasses the pressure of the fracture, damage to the formation happens, that subsequently leads to the loss of circulation difficulties [9]. fig. 2. safety limits for fracture pressure and pore pressure [9] two methods are used for determining the casing setting depths which are: top-down method and bottomup. in this paper the bottom up casing design is used. this strategy will flinch on or after the bottom of the well up to superficial on the other hand, the setting depths are calculated surrounded by the safety feature restrictions (scattered lines). the techniques are as follow: preliminary at the bottom or formation pressure intermittent line at point a), then make a perpendicular line rising to fracture pressure intermittent line at point b as shown in fig. 3. thus, the casing must be adjusted from 4,500 ft. total vertical depth (tvd)to 12,000 ft. total vertical depth to cause 12,000 ft. total vertical depth to be reached with a maximum equivalent mud density. in other words, we will not be broken down the formation at shallow depth (4,500 tvd), and the same concept to another string will be applied [9]. fig. 3. the first step of the bottom design [9] a. h. assi / iraqi journal of chemical and petroleum engineering 23,2 (2022) 35 42 37 the subsequent casing string is founded by sketch a straight line from point b for intersecting the pore pressure intermittent line through point c. at that point make a perpendicular line from the point c until the fracture gradient intermittent line by the side of point d as shown in fig. 4. by conclusion casing should be established from 1,800 ft. tvd to 4,500 ft. tvd [9]. fig. 4. the second stage of the bottom design [9] using the above steps, determine the next casing chain by sketch a straight line from point d to point e and an orthogonal line from point e to point f as shown in fig. 5. so the casing should be adjusted from the surface to 1800 tvd[9]. fig. 5. the third stage of the bottom design [9] depending on the aforementioned bottom-up design principles, 3 series of casing will be required at 1800 ft. tvd, 4500 ft. tvd and finally 12000 ft. tvd as shown in fig. 6 [16]. fig. 6. the final step of the bottom design [9] 2.2. top down method this method of design starts from the surface of the well downwards, where the depths are designed, including the limits of the safety factor, as shown in fig. 7. fig. 7. top down method final design (all steps) [9] method pressure collapse 2.3. in order to determine the depth of installation in a section other than the lower section, the effect of axial tension on the buckling pressure must be taken into consideration, and this involves the use of either a trial and error solution or schematic solutions [10]. at some point from the upper end of the well, the buckling resistance control stops as a major and controlling factor in the design from this point to the surface and begins to control the durability of the joint and the longitudinal compliance, [11] as they are the first consideration in the design, so the lining pipes must achieve the equation 2: 𝐋𝐬 = 𝐏𝐜 𝟎.𝟎𝟓𝟐∗𝛒∗𝐍𝐬 (2) where: ls= setting depth (ft.). ρ=mud weight (ppg). pc= collapse pressure (psi) ns= design factor (dimension less), from the steps bellow, it can be seen that several stages must be calculated as an iterative process in order to calculate the depth of installation, i.e., trial and error [12]. 1data collection, drilling lithology, pressure and geologic 2data identification and verification 3evaluation based on practices and standard 4analysis: actual casing setting depth and design, and casing failure 5recalculation casing setting depth and design by using equation 1 tension load is created from the load of casing and power that formed axially. established on the maximum force idea, the supreme tension force happens in order to its individual load minus the buoyancy next to casing running then in advance the cementing process [13] and as in equation 3 a. h. assi / iraqi journal of chemical and petroleum engineering 23,2 (2022) 35 42 38 bf=1(mw /7848.6) (3) where: bf=buoyancy feature, mw=mud density (kg/m3) the extreme burst weight happens as soon as the cement is pushed through the well. the interior pressure is designed by using equation 4 bearing in mind the hydrostatic pressure related to the cement slurry [14]: pi =psur +gce ×d (4) where: pi = the internal pressure (mpa), psur = pumping surface pressure (mpa) gce = pressure gradient of cement slurry (mpa/m) d= casing shoe depth (m) 3data collection getting data is one of the basics and implementing to get the necessary data is from the south oil company soc / rumelia oil field, where it helped to prepare this research. the basic data consists of:4 wells in rumelia oil field, depth (vertical and measured) lithology, casing program, leak of test lof, pore pressure and fracture pressure, mud density, formation tops, fig. 8 shows the lithological columns for well 4 for rumelia oil field, table 1 represent casing information. table 1 signify top, bottom of formation with pore and fracture pressure. fig. 8. lithological columns for well 4 for rumelia oil field [15] table 1. casing information for surface, intermediate and production [15] tubulars and casing hardware surface casing property md od joint weight id grade collapse burst thread m in m lb./ft. in psi psi prev .casing 42 20 12.5 94 19.124 k-55 520 2110 btc casing 583 13 3/8 12.2 54.5 12.688 j-55 1130 2730 btc tubulars and casing hardware intermediate casing property md od joint weight id grade collapse burst thread m in m lb./ft. in psi psi prev. casing 583 13 3/8 12.2 54.5 12.688 j-55 1130 2730 btc tubulars and casing hardware surface casing property md od joint weight id grade collapse burst thread m in m lb./ft. in psi psi prev .casing 42 20 12.5 94 19.124 k-55 520 2110 btc casing 583 13 3/8 12.2 54.5 12.688 j-55 1130 2730 btc tubulars and casing hardware intermediate casing property md od joint weight id grade collapse burst thread m in m lb./ft. in psi psi prev. casing 583 13 3/8 12.2 54.5 12.688 j-55 1130 2730 btc casing 2036 9 5/8 12.2 47 8 37/50 l-80 4750 6870 vam top tubulars and casing hardware production casing property md od joint weight id grade collapse burst thread m in m lb./ft. in psi psi prev. casing 2036 9 5/8 12.2 47 8 37/50 l-80 4750 6870 vam top casing 2557 7 12.2 29 6.185 0 7030 8160 vam top a. h. assi / iraqi journal of chemical and petroleum engineering 23,2 (2022) 35 42 39 table 2. top, bottom of formation with pore and fracture pressure. formation top md m bottom md m bottom tvd m top ed sg frac bottom ed frac sg top ed pore sg bottom ed sg pore formation 0.0 412.0 412.0 1.34 1.34 1.11 1.11 sandstone 412.0 694.0 694.0 1.26 1.72 1.11 1.08 limestone 694.0 794.0 794.0 1.72 1.71 1.08 1.08 sandstone 794.0 1050.0 1050.0 1.70 1.63 1.08 1.06 sandstone dolostone 1.06ذ 1.06 1.73 1.58 1088.0 1088.0 1050.0 1088.0 1530.0 1530.0 1.73 1.72 1.06 1.06 dolostone 1530.0 1690.0 1690.0 1.72 1.70 1.06 1.07 dolostone 1690.0 1840.0 1840.0 1.70 1.70 1.07 1.08 shale 1840.0 2034.0 2034.0 1.71 1.72 1.08 1.11 dolostone 2034.0 2182.0 2182.0 1.72 1.70 1.11 1.13 limestone 2182.0 2227.0 2227.0 1.70 1.76 1.13 1.12 shale 2227.0 2557.0 25570 1.80 1.80 1.12 1.11 limestone 2557 3440 3440 1.81 1.8 1.13 1.12 limestone 4results and discussion many methods are used for determining the casing setting depth for instant the bottom-up technique and the collapse pressure method, which were used in this study. in general, the bottom-up technique used in development wells. in some circumstances, the exploration wells also use the down top method when facing complex lithology circumstances and nonstandard pressure. this effort included two methods for choosing the depth of installation, as it was found that both methods gave results that are close to the truth, but the bottom-up method was more accurate and closer to reality than the design factors method as in table 3. in hydrocarbon wells it collapses, bursts, in addition to the axial tension demands that must be taken into account when choosing a casing adjusting depth. geological interpretation during the design of the casings is a very important factor, especially knowing the location of the top layer, while sitting the casing and this was proven by boniface and marcus,2015. table 3. formations with facture, pore pressures and lithology for the studied wells well casing setting depth (m) from down up casing type hole size in casing size in casing setting depth (m) from collapse pressure actual casing setting depth (m) a-1 47 conductor 26 20 44 46.5 583(10m in top of dammam) surface 17.5 13 3/8 530 582 1882 (15m into top of sadi) intermediate 12.25 9 5/8 1881 1882 3441 ( 50m above upp er shale) production 8.5 7 3440 3442 a-2 53 conductor 26 20 51 52 544(12m in top of dammam) surface 17.5 13 3/8 542 543 1892 (10m into top of sadi) intermediate 12.25 9 5/8 1891 1892 3431 ( 40m above upp er shale) production 8.5 7 3430 3431 a-3 45 conductor 26 20 44 44 533(11m in top of dammam) surface 17.5 13 3/8 532 532.5 1882 (20m into top of sadi) intermediate 12.25 9 5/8 1882 1881 3440( 33m above upp er shale) production 8.5 7 3439 3440 a-4 56 conductor 26 20 555 55 543(9m in top of dammam) surface 17.5 13 3/8 541 542 1889 (2m into top of sadi) intermediate 12.25 9 5/8 1887 1888 3441 ( 40m above upp er shale) production 8.5 7 3449 3440 for table 4, it represents the frac. and pore pressures for the studied formations, where the highest value for frac. was. 1.8 for limestone formation at a depth of 2256 m, the lowest value for frac. it was 1.26 for limestone formation at a depth of 694 meters. as for the pore pressure, the lowest value was 1.06 for the formation of dolomite at a depth of 1088 meters and the highest value for clay at a depth of 2227 by 1.13. this indicates that the density of the mud used should be less than 1.26 and higher than 1.06 to ensure a safe drilling process without losses or kick. well security is responsible for indicating casing design principles and superior practices to ensure good casings, and as in table 3 and table 5 which represent well security for well a-1 as a sample by using cemcade software. (certainly, cemcade is specific to cement, but in this research, it was used to find the security of the well, which is one of the results given by the aforementioned program table 4. well security for well a-1 for production section security of well station explanation minimum differential pressure depth m time hr:mn accomplishment fracture 657 2036 06:00 accomplishment production 352 2182 06:50 accomplishment burst 7247 zero 08:00 accomplishment collapse 6505 2557 08:40 table 5. the designing of casings for well a-1 casing type md m od in joint m weight lb./ft. id in grade collapse psi burst psi thread conductor 42.0 20 12.5 94.0 19.124 k-55 520 2110 btc surface 583.0 13 3/8 12.2 54.5 12.688 j-55 1130 2730 btc intermediate 2036.0 9 5/8 12.2 47.0 8 37/50 l-80 4750 6870 vamp production 3440 7 12.2 29.0 6.185 l-80 7030 8160 btc a. h. assi / iraqi journal of chemical and petroleum engineering 23,2 (2022) 35 42 40 fracture pressure is a serious factor for drilling fluid weight designing in the oil wells manufacturing. leak-off test information for the used drilling fluid for well a-1 are investigated, and fracture pressure expectation technique for the studied well (drilling can continue drilling under protective casing towards the ahead next casing point, in other words just double checking for the mud density for the next hole). if the drilling fluid pressure surpasses the native tensile failure pressure for the studied formation, in other words, fracture pressure times versus vertical depth, a fracture is founded. for such these cases, the pore pressures frequently are uncharacteristically high and may be surpass what otherwise are innocuous drilling fluids pressures. for the well-studied, the drilling fluid used is considered safe as in fig. 9 and fig. 10. the red line in fig. 9 is designed for safety issue; thus, the first stage of casing design is the safety factor, considering the test limits of borehole drilling. the goal is to avoid drilling difficulties anytime drilling fluid is circulated and this has been proven by syazwan et.al.2016 [16]. as for the blue line, it was designed without relying on safe limits, and thus leads to damage to the casings during the rotation of the drilling mud and during later production processes, and this was confirmed by zhang and yin,2017 [17] about the importance of taking into consideration the impact of fracturing pressure and fluid pressure in the formation. fig. 9. fracture and pore pressure limits by leak-off tests fig. 10. fracture and pore pressure values with depth for well a-1 5conclusions 1this effort presents bottom down method to select casing setting depth for 4 wells. the bottom-up technique is in general used for conventional drilling, nevertheless, not wholly development wells depends on the bottom-up technique. 2casing evaluation and substantial collection should be directed correctly and exactly as stated by the formation type of the studied field because of their important at choosing setting depth processes. 3depending on casing set depth investigation by using the bottom down method. the subsequent specific suggestion may be projected: the mud density should be selected 0.41 to 0.25 pounds/gallon above the value needed to create a hydrostatic pressure that balances the pressure of the fluids in the penetrating layers. 4decision-creation process and is predominantly beneficial for which method is give the exact setting depth is important issues. it was found that the downup method is possible and successful to be used and applied in the fields of southern iraq, such as the rumaila field in southern iraq, which was studied in this research. recommendations for future works, the use of the bottom-up technique for directional and horizontal drilling can be tried as it was used for vertical drilling and proved successful. it is also possible to recommend the use of the top-down method and compare its results with the results of the top-down method. references [1] american petroleum institute (api), "american petroleum institute (api)", api rp 7g: recommended practice for drill stem design and operating limits, sixteenth ed. american petroleum institute (api), washington, d.c. 1998 [2] american petroleum institute (api), "api spec 10 a: specification for cements and materials for well cementing", twenty-third ed. american petroleum institute (api), washington, d.c. 2005. [3] american petroleum institute (api)," api spec 5ct: specification for casing and tubing", ninth ed. american petroleum institute, washington, d.c. 2011 [4] assi, a.h , "the effect of some materials on funnel viscosity reading in water base mud". iraqi geological journal, 53(1e): 32-43,2020. [5] assi, a.h, haiwi.a.a., " enhancing the rheological properties of water -based drilling fluid by utilizing of environmentally -friendly materials". journal of petroleum research and studies", no.32, september 2021, pp. 66-81. https://igj-iraq.org/igj/index.php/igj/article/view/190 https://igj-iraq.org/igj/index.php/igj/article/view/190 https://igj-iraq.org/igj/index.php/igj/article/view/190 https://www.iasj.net/iasj/article/213690 https://www.iasj.net/iasj/article/213690 https://www.iasj.net/iasj/article/213690 https://www.iasj.net/iasj/article/213690 https://www.iasj.net/iasj/article/213690 a. h. assi / iraqi journal of chemical and petroleum engineering 23,2 (2022) 35 42 41 [6] ekasari, n., marbun, b.,"integrated analysis of optimizing casing materials selection of geothermal well by using a model for calculating corrosion rates". in: world geothermal congress, melbourne, australia. 2015 [7] hole, h.," geothermal well design – casing and wellhead", in: petroleum engineering summer school, dubrovnik, croatia,2008. [8] dong, g., chen, p.," a review of the evaluation methods and control technologies for trapped annular pressure in deepwater oil and gas wells". j. natural gas sci. eng. 37, 85–105. 2017 [9] drilling formulas. "casing seat selection –how to select casing setting depth", | june 2, 5:24 am, retrieved from https://www.drillingformulas.com/casing-sizeselection-how-to-select-casing-size-to-match-thedrilling-and-completion-goal/ 2014 [10] lage, a. c. f. m, edson y., nakagawa., rocha l. a. s.,"description and application of new criteria for casing setting depth", offshore technology conference, otc 8464,1997 [11] santos, o., adasani, i., azar, j. j., escorihuela, f., (1995): determination of casing setting depth using kick tolerance concept, petroleum computer conference, spe – 30220 [12] schub, f. j., "conductor and surface casing depth requirement for deep water", annual fall technology conference and exhibition, spe8316,1979. [13] a. h. assi, “potato starch for enhancing the properties of the drilling fluids”, ijcpe, vol. 19, no. 3, pp. 33–40, sep. 2018. [14] zhang, j., and yin, s.x., "fracture gradient prediction: an overview and improved method", pet. sci. doi 10.1007/s12182-017-0182-1 ,2017. [15] data from ministry of oil, rumelia oil field, "drilling program", r-731 (np_ey39_mp) drilling program_dq37, 2022 [16] syazwan, m., shafei, a., paimin, m. r., su’if, m. z., abidin, h. z., ismail, y., natarajan, s., "enhancement of structural conductor design and execution of jetting operation for ultra deepwater wells in brunei", asia pasific oil and gas conference and exhibition, spe – 182427 – ms, 1 – 17,2016. [17] zhang, j., and yin, s.x., "fracture gradient prediction: an overview and improved method", pet. sci. doi 10.1007/s12182-017-0182-1 ,2017. http://www.geothermal-energy.org/pdf/igastandard/iss/2008croatia/hole02.pdf http://www.geothermal-energy.org/pdf/igastandard/iss/2008croatia/hole02.pdf http://www.geothermal-energy.org/pdf/igastandard/iss/2008croatia/hole02.pdf https://www.sciencedirect.com/science/article/abs/pii/s1875510016308447 https://www.sciencedirect.com/science/article/abs/pii/s1875510016308447 https://www.sciencedirect.com/science/article/abs/pii/s1875510016308447 https://www.sciencedirect.com/science/article/abs/pii/s1875510016308447 https://www.drillingformulas.com/casing-size-selection-how-to-select-casing-size-to-match-the-drilling-and-completion-goal/ https://www.drillingformulas.com/casing-size-selection-how-to-select-casing-size-to-match-the-drilling-and-completion-goal/ https://www.drillingformulas.com/casing-size-selection-how-to-select-casing-size-to-match-the-drilling-and-completion-goal/ https://onepetro.org/otconf/proceedings-abstract/97otc/all-97otc/otc-8464-ms/45282 https://onepetro.org/otconf/proceedings-abstract/97otc/all-97otc/otc-8464-ms/45282 https://onepetro.org/otconf/proceedings-abstract/97otc/all-97otc/otc-8464-ms/45282 https://onepetro.org/otconf/proceedings-abstract/97otc/all-97otc/otc-8464-ms/45282 https://onepetro.org/spepcc/proceedings-abstract/95pcc/all-95pcc/spe-30220-ms/57503 https://onepetro.org/spepcc/proceedings-abstract/95pcc/all-95pcc/spe-30220-ms/57503 https://onepetro.org/spepcc/proceedings-abstract/95pcc/all-95pcc/spe-30220-ms/57503 https://onepetro.org/spepcc/proceedings-abstract/95pcc/all-95pcc/spe-30220-ms/57503 https://onepetro.org/speatce/proceedings-abstract/79spe/all-79spe/spe-8316-ms/134852 https://onepetro.org/speatce/proceedings-abstract/79spe/all-79spe/spe-8316-ms/134852 https://onepetro.org/speatce/proceedings-abstract/79spe/all-79spe/spe-8316-ms/134852 https://onepetro.org/speatce/proceedings-abstract/79spe/all-79spe/spe-8316-ms/134852 https://doi.org/10.31699/ijcpe.2018.3.4 https://doi.org/10.31699/ijcpe.2018.3.4 https://doi.org/10.31699/ijcpe.2018.3.4 https://onepetro.org/speapog/proceedings-abstract/16apog/all-16apog/spe-182427-ms/185407 https://onepetro.org/speapog/proceedings-abstract/16apog/all-16apog/spe-182427-ms/185407 https://onepetro.org/speapog/proceedings-abstract/16apog/all-16apog/spe-182427-ms/185407 https://onepetro.org/speapog/proceedings-abstract/16apog/all-16apog/spe-182427-ms/185407 https://onepetro.org/speapog/proceedings-abstract/16apog/all-16apog/spe-182427-ms/185407 https://onepetro.org/speapog/proceedings-abstract/16apog/all-16apog/spe-182427-ms/185407 a. h. assi / iraqi journal of chemical and petroleum engineering 23,2 (2022) 35 42 42 االعتبارات الجيولوجية المتعلقة بتحديد عمق الغالف واختيار عمق آبار النفط العراقية )دراسة حالة( امل حبيب عاصي العراق ,بغداد ,جامعة بغداد,قسم هندسة النفط الخالصة حيوية يجب الحفاظ عليها في العمر االفتراضي للبئر ، ومن أحد مكونات الغالف ، سالمة البئر هي ميزة أساسيتين: خالل من ، الغالف يعتبر والخارجية. الداخلية األحمال جميع تحمل على قادًرا يكون أن يجب المة البئر. تصميم الغالف وتعديل عمق الغالف ، وهو أساسًيا اثناء ثقب البئر حيث يلعب دوًرا مهًما في س عليها الحصول ويمكن البئر في المسام وضغط التكسير ضغط على بناًء الغالف مجموعة أعماق تحديد يتم عادًة من معلومات محددة جيًدا. بناًء على التحليالت باستخدام التقنيات المحّسنة في هذه الدراسة ، يمكن توقع الدرجة اختيار يتم أن يجب التالي: الخاص إعداد االقتراح لعمق وفًقا ودقيق صحيح بشكل والمواد األولى الغالف واالستراتيجية في المجال المدروس الذي يجب أن يؤخذ في االعتبار بشكل قاطع في فترة الحفر و بعد االنتهاء منها ، مع ذلك في المقابل في اإلنتاج والصيانة ، والتحويل إلى بئر الحقن أو العكس ، باإلضافة إلى ا ، مرحلة الكسر تدرج من تتكون والتي ، الغالف مقعد عمق في تتحكم التي الميزات دراسة تمت إلغالق. وضغط المسام مع مشكالت أخرى هي القطع المتبقية من الصخور. يمكن الحفاظ على تحديد مقعد الغالف من تحديد سائل الحفر المناسب. وفًقا لنتائج فحص ضغط الكسر وضغط الم عمق خالل التحقيق في سام ونتائج ضبط الغالف عن طريق تقنية من أسفل إلى أعلى ، تم الحصول على النتائج على كل غالف لآلبار األربعة 47، يبلغ عمق غالف االعلى a.بالنسبة للبئر المدروسة. من النقطة المرجعية المصممة من المنضدة الدوارة متًرا. أخيًرا ، لعمق غالف 1882متًرا ، وعمق إعداد الغالف المتوسط 533متًرا ، وعمق الغالف السطحي هو اعلى 3441اإلنتاج اسفل التصاعدية الطريقة أن وجد فقد ، االنهيار ضغط طريقة مع بالمقارنة متر. حقيقية. تم تضمين نتائج اآلبار األخرى في نتائج البحث أعطت نتائج قريبة ومماثلة للنتائج ال الغالف ، التكوين ، تصميم بئرالنفط ، ضبط العمق ، ضغط التكوين الكلمات الدالة: available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.23 no.2 (june 2022) 47 – 53 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: zaid waadulla rashad , email: zaid@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. studying and analyzing operating conditions of hollow fiber membrane preparation process: a review paper zaid waadulla rashad university of baghdad/college of engineering/chemical eng. dept. abstract polymeric hollow fiber membrane is produced by a physical process called wet or dry/wet phase inversion; a technique includes many steps and depends on different factors (starting from selecting materials, end with post-treatment of hollow fiber membrane locally manufactured). this review highlights the most significant factors that affect and control the characterization and structure of ultrafiltration hollow fiber membranes used in different applications. three different types of polymers (polysulfone psf, polyethersulfone pes or polyvinyl chloride pvc) were considered to study morphology change and structure of hollow fiber membranes in this review. these hollow fiber membranes were manufactured with different process conditions and a reasonable starting point for factors remained constant to study the changing effect of specific factors. keywords: hollow fiber membranes, phase inversion, ultrafiltration, polymers received on 26/05/2022, accepted on 19/06/2022, published on 30/06/2022 https://doi.org/10.31699/ijcpe.2022.2.7 1introduction membrane separation is the most flexible reliable and promising technology over the past decades. membrane technology offers high performance among other processes adsorption, extraction, distillation, and leaching in terms of environment friendly and cost effect [1], [2]. a membrane is described as a barrier separating two phases [3] made of high chemical stability materials. membranes are often linked to their application to choose the right process and membrane module [4]. from the food industry to desalination (providing drinking water for millions around the world), dialysis (saving the life of kidney disease patients), automotive industry (electroplating bath recovery), and gas separation, membrane processes can be applied to a wide range of applications [4]. fig. 1 describes membranes classification according to their morphology into dense, porous, and composite. asymmetric porous membranes invented by loeb and sourirjan, [5] are the most commercially available membranes in the present day. the structure of asymmetric membranes is a defect-free skin layer based on a porous layer [4]. this structure can be achieved by simple principles but is quite tricky with a process called phase inversion. the process starts with polymer solution thermodynamically unstable by one of four methods; immersion precipitation, vapor induced phase separation, thermally induced phase separation, and dry casting, which leads to polymer separation to polymer lean create pores and voids and polymer-rich phases the porous structure of membrane [4-6]. fig. 1. membrane classification according to structure morphology [4] hollow fiber ultrafiltration membrane was first stated in1966, this type of membrane is not suitable for ro or nf process which applied high pressure because of poor mechanical properties [7], however, it is one of the most interesting membranes modules as it has many advantages among other modules such as high productivity per unit volume [8], self-supporting and easy operation [4]. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:zaid@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2022.2.7 z. w. rashad / iraqi journal of chemical and petroleum engineering 23,2 (2022) 47 53 48 the importance of hollow fiber membranes as lowpressure membranes (lphf) is their ultrafiltration performance, ultrafiltration together with microfiltration gives good separation performance for drinking water. recent studies suggest that mf and uf can remove all particles and colloids as well as viruses completely when used with suitable pre-treatment or post-treatment which gives this technology advantage to be the new technology generation for drinking water of the 21st century [9]. fabrication of hollow fiber membranes is not an easy operation especially when specific structure morphology is required [10]. this review demonstrates literature from some researchers to simplify the process steps and give start point for researchers to study the change in hollow fiber membranes structure by changing one or two factors of the preparation process. however, many researchers reported different and conflicting results for the same operating conditions but different polymers, in terms of permeation and rejection (membranes performance). 2preparation main steps and factors the purpose of studying membranes technology is to improve its performance (flux and rejection) via structure control as mentioned before [1]. the structure is usually sponge-like or finger-like with a selective skin layer on the surface as shown in fig. 2, sponge-like is the favored as finger-like leads to a lack in the mechanical stability of hollow fiber membranes [4]. preparation steps are the dope solution, spinning process, and post-treatment of hollow fiber membranes, these steps are discussed in the next section, and all operating conditions remain constant except for the factor to be changed and studied. fig. 2. (a) finger-like structure, (b) sponge-like structure, (c) uniform sponge-like structure [11] 2.1. dope solution preparation the first step to prepare dope or polymer solution is to select a suitable polymer powder and good polymer solvent. after materials selection, a magnetic stirrer is required to homogenize the polymer solution as shown in fig. 3. fig. 3. polymer solution preparation [12] firstly, polymer powder should be dried to remove moisture. for psf polymer drying, 60 °c for at least 12 h is required then polymer powder added to nmp solvent of 22/88 psf/nmp weight percent and mixed until homogenized at room temperature (25-27 °c) [13]. pvc polymer is a good inexpensive choice for hollow fiber manufacturing[n]. pvc powder was dissolved in dimethyl acetamide dmac chemically and thermally stable solvent [14] after dried for 24 hr. at 70 °c under continuous mixing period (5 days) at room temperature (25 °c). pvc/dmac ratio was 14/88 w/w, [10]. mustaffar et al. [1] chose pes polymer with three different concentrations and polyethylene glycol peg as polymer additive, 18/72/10, 20/70/10, and 28/62/10, pes/nmp/peg weight percent of 100-gram polymer samples were stirred at 30 °c. wang et al. [15] followed the system psf/nmp/h2o ( water as a non-solvent additive) and also use three concentrations of psf polymer 26/70/4, 28/68/4, and 30/66/4, psf polymer powder was dried at 100 °c for 10 hr. adding peg to polymer solution in the system of mustaffar et al. [1] is to enhance porosity on the membrane skin layer. polymer concentration together with the solvent ratio is the most significant parameter that directly affects membrane properties. increasing concentration leads to an increase in dope solution viscosity, dense skin layer becomes thicker, and reduction in macro voids, [1] as well as transferring membrane structure from finger-like to sponge-like [7]. on the other hand, adding a specific amount of non-solvent (water, ethanol, acetone) to the polymer solution well provides a good membrane porous structure [13-16]. 2.2. spinning process the spinning process includes several stages as shown in fig. 4, starting with dope solution located in a spinning container fig. 4 no.4 and leaving for 24 hr. to de-bubble or de-gas polymer solution [10], [16] [17]. z. w. rashad / iraqi journal of chemical and petroleum engineering 23,2 (2022) 47 53 49 the dope solution was pressed to a spinneret with a specific inner and outer diameter by nitrogen pressure, 0.5, 0.6, 0.75, or 0.8 bar are recommended pressure as the morphology of the hollow fiber membrane was not affected by changing dope solution pressure in this range [12]. fig. 4. spinning process stages, (1) nitrogen cylinder, (2) pressure valve regulator, (3) nitrogen pressure gauge, (4) dope solution container, (5) dope solution control valve, (6) bore fluid container, (7) dosing pump, (8) spinneret, (9) air gap, (10) coagulants bath, (11) take-up unit, (12) hollow fiber collecting vessel, (13) distilled water for extra wash [12] a. air gap airgap is defined as the distance between the spinneret and the external coagulants surface, this distance switches the phase inversion process from wet phase inversion to dry/wet phase inversion [10]. many researchers study the effect of air gap length on the hollow fiber membrane's structure and came back with confusing results about how the air gap increase or decrease membrane performance in terms of permeation and rejection, table 1 illustrates some of the researcher's conclusion about air gap length outcome for polysulfone psf, polyvinyl chloride pvc, and polyether sulfone pes. table 1. effect of air gap on membrane performance reported by different researchers polymer air gap length permeation separation factor reference psf increased decreased increased aptel et al. [18] psf increased no-effect no-effect east et al. [19] psf increased increased then decreased with further increase of airgap length kim et al. [20] psf increased not significantly affected increased tsai et al. [21] pes 15-120 cm decreased increased et al. [22] pes 0-14.4 cm significant decrease chung and hu [23] pvc 5-25 cm increased decreased khayet et al. [10] for psf polymer tsai et al. [21] explained the increase in the separation factor is due to the increase in the skin layer of the hollow fiber membranes structure. chung and hu [23] describe the change in permeation as related to the high elongation stress of hollow fiber membrane in the presence of an air gap. khayet et al. [10] indicated an increase in the mean pores of outer hollow fiber membranes surface while the inner pore size almost remained the same with increasing air gap and also linked this change to elongation force. b. bore fluid and coagulants bore fluid or internal coagulant is maintained in a container fig. 4 no. 6 and pumped with a dosing pump to the inner tube of spinneret together with a dope solution which inter the external spinneret tube, bore fluid fed with a very low flow rate (2, 3 or 4 ml/min), distilled water at room temperature is a good choice [10], [12]. polymer falls from spinneret with a speed rate the same as gravity speed [10]. bore fluid or internal coagulant also a key role to control membrane structure, distilled water is a good non-solvent for psf while alcohol (ethanol) is weak, choosing the optimized ratio of water/alcohol mixture may reduce the big macro-voids in membrane structure [15]. once the nascent hollow fiber membranes touch the external coagulation fluid (usually tap water), solvent non-solvent exchange occurred and form the asymmetric structure, generally the fast the coagulation rate the more finger-like macro voids formed while the slow coagulation rate gives the favored sponge-like structure [13]. to slow down the coagulation rate, a small amount of solvent additive to bore fluid or coagulant bath well reduces the coagulation and induces the formation of a sponge-like structure [15]. appropriate additives should be environmentally friendly, low toxicity, and commercially available. the best coagulant to be used is water, the nmp and dmac are the best as solvent additives [15]. the temperature of coagulants is considered an important factor to control membrane structure, wang et al. reported that reducing coagulation bath temperature from 27 c to 20 °c increases the membrane permeation and decreases the selectivity, while further temperature reduction to 10-15 °c leads to a significant reduction in membrane selectivity performance due to the formation of macro voids on the membrane surface [15]. 2.3. post treatment the final step of fabrication of hollow fiber membrane is post-treatment, the importance of post-treatment is to avoid membrane collapse and get rid of residual solvent [10], [15], [16]. many researchers reported a different kind of post-treatment to protect the membrane from damage. z. w. rashad / iraqi journal of chemical and petroleum engineering 23,2 (2022) 47 53 50 wang et al. [15] suggest keeping hollow fiber psf membranes in water for 72 hr. followed by a drying step at conditions of 25 °c and (60-65%) relative humidity. khayet et al. [10] made it three steps, first, wash hollow fiber pvc membranes with water for 48 hr. to remove the solvent, and second immerse hollow fiber membranes in glycerol aqueous solution of 40% volume ratio to avoid collapse, and third dry at room temperature. another method is to treat hollow fiber membranes with non-solvent with low surface tension such as ethanol [13], mansourizadeh & ismail [13] submerged psf hollow fiber membranes in ethanol for half an hour and then let the non-solvent evaporate by air exposure at room temperature to prevent pores breakdown. for pes hollow fiber membranes, mustaffar et al. recommended two days of water washing, two days of methanol immersion, and a drying period by hanging hollow fiber membranes for 7 days before use. 3hollow fiber membranes characterization and performance the characterization of hollow fiber membranes was evaluated by scanning electron microscope sem as this device gives a clear image of membrane structure in terms of skin layer thickness; porosity distribution and pores shape also give a good indicator of inner and outer diameter measurements [16]. the inner and outer diameter also can be measured by a linear vernier microscope with ±1µm. accuracy [10]. permeation and selectivity performance required a specially designed lab-made unit as shown in fig. 6 which was suggested by some researchers. before explaining the performance system the hollow fiber must be cut to more than 20 cm (depending on tube design) and secured in a special tube usually made of stainless steel with an inlet and outlet open on the side as shown in fig. 5 and get a free end of membranes by sealing the two end of the tube with epoxy resins and let it cure for 24 hr. [12], [24]. fig. 5. hollow fiber membrane special tube [24] fig. 6. schematic diagram of hollow fiber membrane performance system, (1) feed tank, (2) pump, (3) control valve, (4) flow meter, (5) gauge pressure, (6) hollow fiber tube, (7) gauge pressure, (8) retentate, (9) permeate, (10) collecting tank [12] performance system for pure water permeation pwp includes forcing distilled water to the inlet tube with specific pressure and flow rate and passes through hollow fiber membranes from outer to the inner surface and by collecting permeates for a specific time, pwp can be calculated by the following equation: 𝑃𝑊𝑃𝐹 = q a δp (1) where: q: volumetric flow rate, l/h a: membrane surface area, m2 δp: pressure drop, bar [25] for rejection calculation, a solution with a specific amount of peg (800, 1000 ppm) [12], [16] is pumped instead of distilled water and the equation used was as follows: 𝑅(%) = ( 1 − 𝐶𝑝 𝐶𝑓 ) × 100 (2) where: cp: concentration of peg of permeation, ppm cf: concentration of peg of the feed solution, ppm [25] note: uv spectrometer is used to find concentration by knowing peg wavelength and create a calibration curve 4conclusion there are many factors to be controlled in the fabrication of hollow fiber membranes. some of these factors direly affect the structure of the membrane and eventually, the overall performance and even slight change give a different morphology. it is important to keep operating conditions constant when studying the change of specific factor. z. w. rashad / iraqi journal of chemical and petroleum engineering 23,2 (2022) 47 53 51 1polymer concentration is remarked as the most effective on the morphology of hollow fiber membranes, the high the concentration the thick the skin layer, and a more sponge-like structure is produced. from researcher reports, 14% of polymer concentration and above is a good start, not to forget the effect of suitable additives to the dope solution on the performance of the membranes. dmac is a suitable solvent for a different type of polymers as it is miscible with water and have good thermal and chemical stability 2the air gap was the most conflicting factor, however, 5-10 cm of air gap was expected to enhance membranes selectivity, especially for psf and pes while decreasing it for pvc 3water is fantastic for bore fluid and coagulants with appropriate additives, alcohol in a coagulant bath gives a reduction in macro-voids formation. a small amount of solvent like dmac to bore fluid or coagulation bath raises the sponge-like structure of membranes 4post-treatment of hollow fiber membranes has two main reasons, wash residual solvent, and prevent membrane collapse. 5finally, the favorite performance (increasing permeation or selectivity) of hollow fiber membranes depends on its application, gas separation, or drinking water production abbreviation psf: poly sulfone pes poly ether sulfone pvc poly vinyl chloride ro reverse osmosis nf nano filtration lphf low pressure hollow fiber uf ultra-filtration nmp n-methyl-2-pyrrolidone dmac n,ndimethyl acetamide sem scanning electron microscope pwpf pure water permeation uv ultraviolet references [1] m. i. mustaffar, a. f. ismail, and r. m. illias. "study on the effect of polymer concentration on hollow fiber ultrafiltration membrane performance and morphology." in regional symposium on membrane science and technology, malaysia. 2004. [2] m. s. m. ali, "development of integrally skinned polysulfone ultrafiltration membrane: effect of casting parameter." phd diss., msc. thesis, university sains malaysia, 2005. [3] van vught, f. a., willem franciscus catherina kools, and belgië te hoogstraten. "membrane formation by phase inversion in multicomponent polymer system." phd diss., university of twente, 1998. [4] nunes, suzana pereira, and klaus-viktor peinemann. "membrane technology in the chemical industry second." environmental engineering and management journal 6, no. 1, 75-76, 2007. [5] s. a altınkaya, "modeling of asymmetric membrane formation by a combination of dry/wet phase inversion processes." desalination 2006. [6] w. chinpa,. "preparation and characterization of an asymmetric porous poly (vinyl chloride)/poly (methyl methacrylate-comethacrylic acid) membrane." scienceasia 34 385-389, 2008. [7] a. nazif, h. karkhanechi, e. saljoughi, s. mahmoud mousavi and h. matsuyama, "effective parameters on fabrication and modification of braid hollow fiber membranes: a review." membranes 11, no. 11, 884, 2021. [8] ali behboudi, sanaz ghiasi, toraj mohammadi, mathias ulbricht "preparation and characterization of asymmetric hollow fiber polyvinyl chloride (pvc) membrane for forward osmosis application." separation and purification technology 270 2021: 118801. [9] j. tian, z. chen, y. yang, h. liang, j. nan, and g. li, "consecutive chemical cleaning of fouled pvc membrane using naoh and ethanol during ultrafiltration of river water." water research 44, no. 1, pp. 59-68, 2010. [10] m. khayet, m.c. garcía-payoa, f.a. qusayb, and m.a. zubaidy, "structural and performance studies of poly (vinyl chloride) hollow fiber membranes prepared at different air gap lengths." journal of membrane science 330, no. 1-2, pp.30-39, 2009. [11] ullmann's encyclopedia of industrial chemistry, 6th edition, wiley inter science, weinheim, 2002. [12] n. k. taieh, "preparation and characterization of pvc hollow fiber membranes for ultrafiltration application", msc. thesis, technical college-baghdad, iraq, 2010. [13] a. mansourizadeh1 & a. fauzi ismail, "effects of fabrication parameters on the morphology of porous polysulfone hollow fiber membranes.", jurnal teknologi, 49(f), pp. 81– 89, dis. 2008. [14] tamino people and molecules, "dimethylacetamide technical data sheet", retrieved from https://www.eastman.com/pages/taminco.aspx march, 2011 [15] d. wang, w.k. teo a, and k. li, "preparation and characterization of high-flux polysulfone hollow fibre gas separation membranes." journal of membrane science 204, no. 1-2, pp.247-256, 2002. https://www.researchgate.net/profile/ahmad-ismail-18/publication/242413936_study_on_the_effect_of_polymer_concentration_on_hollow_fiber_ultrafiltration_membrane_performance_and_morphology/links/0046352df074675218000000/study-on-the-effect-of-polymer-concentration-on-hollow-fiber-ultrafiltration-membrane-performance-and-morphology.pdf https://www.researchgate.net/profile/ahmad-ismail-18/publication/242413936_study_on_the_effect_of_polymer_concentration_on_hollow_fiber_ultrafiltration_membrane_performance_and_morphology/links/0046352df074675218000000/study-on-the-effect-of-polymer-concentration-on-hollow-fiber-ultrafiltration-membrane-performance-and-morphology.pdf https://www.researchgate.net/profile/ahmad-ismail-18/publication/242413936_study_on_the_effect_of_polymer_concentration_on_hollow_fiber_ultrafiltration_membrane_performance_and_morphology/links/0046352df074675218000000/study-on-the-effect-of-polymer-concentration-on-hollow-fiber-ultrafiltration-membrane-performance-and-morphology.pdf https://www.researchgate.net/profile/ahmad-ismail-18/publication/242413936_study_on_the_effect_of_polymer_concentration_on_hollow_fiber_ultrafiltration_membrane_performance_and_morphology/links/0046352df074675218000000/study-on-the-effect-of-polymer-concentration-on-hollow-fiber-ultrafiltration-membrane-performance-and-morphology.pdf https://www.researchgate.net/profile/ahmad-ismail-18/publication/242413936_study_on_the_effect_of_polymer_concentration_on_hollow_fiber_ultrafiltration_membrane_performance_and_morphology/links/0046352df074675218000000/study-on-the-effect-of-polymer-concentration-on-hollow-fiber-ultrafiltration-membrane-performance-and-morphology.pdf https://www.researchgate.net/profile/ahmad-ismail-18/publication/242413936_study_on_the_effect_of_polymer_concentration_on_hollow_fiber_ultrafiltration_membrane_performance_and_morphology/links/0046352df074675218000000/study-on-the-effect-of-polymer-concentration-on-hollow-fiber-ultrafiltration-membrane-performance-and-morphology.pdf https://ris.utwente.nl/ws/files/6077441/t0000005.pdf https://ris.utwente.nl/ws/files/6077441/t0000005.pdf https://ris.utwente.nl/ws/files/6077441/t0000005.pdf https://ris.utwente.nl/ws/files/6077441/t0000005.pdf https://ris.utwente.nl/ws/files/6077441/t0000005.pdf http://www.eemj.eu/index.php/eemj/article/view/321 http://www.eemj.eu/index.php/eemj/article/view/321 http://www.eemj.eu/index.php/eemj/article/view/321 http://www.eemj.eu/index.php/eemj/article/view/321 https://gcris.iyte.edu.tr/handle/11147/2170 https://gcris.iyte.edu.tr/handle/11147/2170 https://gcris.iyte.edu.tr/handle/11147/2170 https://www.thaiscience.info/journals/article/scas/10460458.pdf https://www.thaiscience.info/journals/article/scas/10460458.pdf https://www.thaiscience.info/journals/article/scas/10460458.pdf https://www.thaiscience.info/journals/article/scas/10460458.pdf https://www.mdpi.com/2077-0375/11/11/884 https://www.mdpi.com/2077-0375/11/11/884 https://www.mdpi.com/2077-0375/11/11/884 https://www.mdpi.com/2077-0375/11/11/884 https://www.mdpi.com/2077-0375/11/11/884 https://www.sciencedirect.com/science/article/abs/pii/s138358662100513x https://www.sciencedirect.com/science/article/abs/pii/s138358662100513x https://www.sciencedirect.com/science/article/abs/pii/s138358662100513x https://www.sciencedirect.com/science/article/abs/pii/s138358662100513x https://www.sciencedirect.com/science/article/abs/pii/s138358662100513x https://www.sciencedirect.com/science/article/abs/pii/s138358662100513x https://www.sciencedirect.com/science/article/abs/pii/s0043135409005673 https://www.sciencedirect.com/science/article/abs/pii/s0043135409005673 https://www.sciencedirect.com/science/article/abs/pii/s0043135409005673 https://www.sciencedirect.com/science/article/abs/pii/s0043135409005673 https://www.sciencedirect.com/science/article/abs/pii/s0043135409005673 https://www.sciencedirect.com/science/article/abs/pii/s037673880801048x https://www.sciencedirect.com/science/article/abs/pii/s037673880801048x https://www.sciencedirect.com/science/article/abs/pii/s037673880801048x https://www.sciencedirect.com/science/article/abs/pii/s037673880801048x https://www.sciencedirect.com/science/article/abs/pii/s037673880801048x https://onlinelibrary.wiley.com/doi/book/10.1002/14356007 https://onlinelibrary.wiley.com/doi/book/10.1002/14356007 https://www.researchgate.net/profile/amir-mansourizadeh/publication/237535436_effects_of_fabrication_parameters_on_the_morphology_of_porous_polysulfone_hollow_fiber_membranes/links/0046352cf43ba8d5a2000000/effects-of-fabrication-parameters-on-the-morphology-of-porous-polysulfone-hollow-fiber-membranes.pdf https://www.researchgate.net/profile/amir-mansourizadeh/publication/237535436_effects_of_fabrication_parameters_on_the_morphology_of_porous_polysulfone_hollow_fiber_membranes/links/0046352cf43ba8d5a2000000/effects-of-fabrication-parameters-on-the-morphology-of-porous-polysulfone-hollow-fiber-membranes.pdf https://www.researchgate.net/profile/amir-mansourizadeh/publication/237535436_effects_of_fabrication_parameters_on_the_morphology_of_porous_polysulfone_hollow_fiber_membranes/links/0046352cf43ba8d5a2000000/effects-of-fabrication-parameters-on-the-morphology-of-porous-polysulfone-hollow-fiber-membranes.pdf https://www.researchgate.net/profile/amir-mansourizadeh/publication/237535436_effects_of_fabrication_parameters_on_the_morphology_of_porous_polysulfone_hollow_fiber_membranes/links/0046352cf43ba8d5a2000000/effects-of-fabrication-parameters-on-the-morphology-of-porous-polysulfone-hollow-fiber-membranes.pdf https://www.researchgate.net/profile/amir-mansourizadeh/publication/237535436_effects_of_fabrication_parameters_on_the_morphology_of_porous_polysulfone_hollow_fiber_membranes/links/0046352cf43ba8d5a2000000/effects-of-fabrication-parameters-on-the-morphology-of-porous-polysulfone-hollow-fiber-membranes.pdf https://www.researchgate.net/profile/amir-mansourizadeh/publication/237535436_effects_of_fabrication_parameters_on_the_morphology_of_porous_polysulfone_hollow_fiber_membranes/links/0046352cf43ba8d5a2000000/effects-of-fabrication-parameters-on-the-morphology-of-porous-polysulfone-hollow-fiber-membranes.pdf https://www.eastman.com/pages/taminco.aspx https://www.sciencedirect.com/science/article/abs/pii/s0376738802000479 https://www.sciencedirect.com/science/article/abs/pii/s0376738802000479 https://www.sciencedirect.com/science/article/abs/pii/s0376738802000479 https://www.sciencedirect.com/science/article/abs/pii/s0376738802000479 z. w. rashad / iraqi journal of chemical and petroleum engineering 23,2 (2022) 47 53 52 [16] f. m. hussein, a. s. merzah, and z. w. rashad, “preparation of pvc hollow fiber membrane using (dmac/acetone)”, ijcpe, vol. 15, no. 4, pp. 81–87, dec. 2014. [17] a. al-obaidy, “a morphological study of alumina hollow fiber membrane”, ijcpe, vol. 17, no. 3, pp. 117–123, sep. 2016. [18] p. aptel, n. abidine, f. ivaldi, j.p. lafaille, "polysulfone hollowfibres-effect of spinning conditions on ultrafiltration properties", j. membr. sci. 22, pp. 199–215, 1985. [19] g.c. east, j.e. mcintyre, v. rogers, s.c. senn, "production of porous hollow polysulfone fibers for gas separation, in: proceedings of the fourth boc" priestly conference, 62., royal society of chemistry, london, 1986. [20] h. kim, y.i. park, j. jagel, k.h. lee, "the effects of spinning conditions on the structure formation and the dimension of the hollow-fiber membranes and their relationship with the permeability in dry–wet spinning technology", j. appl. polymer sci. 57 (1995) 1637–1645. [21] n.h.a. tsai, d.h. huang, s.c. fan, y.c. yang, c.l. li, k.r. lee, j.y. lai, investigation of surfactant addition effect on the vapor permeation of aqueous ethanol mixtures through polysulfone hollow fiber membranes, j. membr. sci. 198 (2002) 245–258. [22] x. miao, s. sourirajan, h. zhang,w.w.y. lau, "production of polyethersulfone hollow fiber ultrafiltration membranes. part i. effects of water (internal coagulant) flow rate and length of air gap", sep. sci. technol. 31 (1996) 141–156. [23] t.s. chung, x. hu, effect of air gap distance on the morphology and thermal properties or polyethersulfone hollow fibers, j. appl. polymer sci. 66 (1997) 1067–1077. [24] z. w. rashad, "operating system for preparation hollow fiber membranes using for water treatment" project research h.d., technical collage baghdad, 2012. [25] y. yang, d.yang, s. zhang, j. wang, and x. jian, "preparation and characterization of poly (phthalazinone ether sulfone ketone) hollow fiber ultrafiltration membranes with excellent thermal stability." journal of membrane science 280, no. 1-2 (2006): 957-968. https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/300 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/300 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/300 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/300 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/219 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/219 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/219 https://www.sciencedirect.com/science/article/abs/pii/s0376738800812806 https://www.sciencedirect.com/science/article/abs/pii/s0376738800812806 https://www.sciencedirect.com/science/article/abs/pii/s0376738800812806 https://www.sciencedirect.com/science/article/abs/pii/s0376738800812806 https://onlinelibrary.wiley.com/doi/abs/10.1002/app.1995.070571310 https://onlinelibrary.wiley.com/doi/abs/10.1002/app.1995.070571310 https://onlinelibrary.wiley.com/doi/abs/10.1002/app.1995.070571310 https://onlinelibrary.wiley.com/doi/abs/10.1002/app.1995.070571310 https://onlinelibrary.wiley.com/doi/abs/10.1002/app.1995.070571310 https://onlinelibrary.wiley.com/doi/abs/10.1002/app.1995.070571310 https://www.sciencedirect.com/science/article/abs/pii/s0376738801006615 https://www.sciencedirect.com/science/article/abs/pii/s0376738801006615 https://www.sciencedirect.com/science/article/abs/pii/s0376738801006615 https://www.sciencedirect.com/science/article/abs/pii/s0376738801006615 https://www.sciencedirect.com/science/article/abs/pii/s0376738801006615 https://www.sciencedirect.com/science/article/abs/pii/s0376738801006615 https://www.tandfonline.com/doi/abs/10.1080/01496399608000687 https://www.tandfonline.com/doi/abs/10.1080/01496399608000687 https://www.tandfonline.com/doi/abs/10.1080/01496399608000687 https://www.tandfonline.com/doi/abs/10.1080/01496399608000687 https://www.tandfonline.com/doi/abs/10.1080/01496399608000687 https://onlinelibrary.wiley.com/doi/abs/10.1002/(sici)1097-4628(19971107)66:6%3c1067::aid-app7%3e3.0.co;2-g https://onlinelibrary.wiley.com/doi/abs/10.1002/(sici)1097-4628(19971107)66:6%3c1067::aid-app7%3e3.0.co;2-g https://onlinelibrary.wiley.com/doi/abs/10.1002/(sici)1097-4628(19971107)66:6%3c1067::aid-app7%3e3.0.co;2-g https://onlinelibrary.wiley.com/doi/abs/10.1002/(sici)1097-4628(19971107)66:6%3c1067::aid-app7%3e3.0.co;2-g https://www.researchgate.net/profile/zaid-rashad/publication/328726011_operating_system_for_preparation_hollow_fiber_membranes_using_for_water_treatment/links/5bde195fa6fdcc3a8dbcb75d/operating-system-for-preparation-hollow-fiber-membranes-using-for-water-treatment.pdf https://www.researchgate.net/profile/zaid-rashad/publication/328726011_operating_system_for_preparation_hollow_fiber_membranes_using_for_water_treatment/links/5bde195fa6fdcc3a8dbcb75d/operating-system-for-preparation-hollow-fiber-membranes-using-for-water-treatment.pdf https://www.researchgate.net/profile/zaid-rashad/publication/328726011_operating_system_for_preparation_hollow_fiber_membranes_using_for_water_treatment/links/5bde195fa6fdcc3a8dbcb75d/operating-system-for-preparation-hollow-fiber-membranes-using-for-water-treatment.pdf https://www.researchgate.net/profile/zaid-rashad/publication/328726011_operating_system_for_preparation_hollow_fiber_membranes_using_for_water_treatment/links/5bde195fa6fdcc3a8dbcb75d/operating-system-for-preparation-hollow-fiber-membranes-using-for-water-treatment.pdf https://www.sciencedirect.com/science/article/abs/pii/s0376738806001906 https://www.sciencedirect.com/science/article/abs/pii/s0376738806001906 https://www.sciencedirect.com/science/article/abs/pii/s0376738806001906 https://www.sciencedirect.com/science/article/abs/pii/s0376738806001906 https://www.sciencedirect.com/science/article/abs/pii/s0376738806001906 https://www.sciencedirect.com/science/article/abs/pii/s0376738806001906 z. w. rashad / iraqi journal of chemical and petroleum engineering 23,2 (2022) 47 53 53 تحضير االغشية النفاذية المجوفة ورقة مراجعة في دراسة وتحليل ظروف التشغيل لعملية زيد وعدهللا رشاد جامعة بغداد/كلية الهندسة الخالصة تنتج االغشية النفاذية المجوفة عن طريق عملية فيزيائية تسمى انقالب الطور الرطب أو الجاف / الرطب. وانتهاًء التصنيع، مواد اختيار من )بدًءا مختلفة عوامل على وتعتمد الخطوات من العديد التقنية تتضمن ت محلًيا(. المصنوعة المجوفة النفاذية لالغشية الالحقة أهم بالمعالجة على الضوء هذه المراجعة دراسة سلط الداخلي التركيب توصيف في وتتحكم تؤثر التي الفائق ألالعوامل الترشيح ذات المجوفة األلياف غشية المستخدمة في التطبيقات المختلفة. سلفون )بولي البوليمرات من مختلفة أنواع ثالثة على باالعتماد الدراسة سلف psfتمت إيثر بولي ون ، pes و بولي فينيل كلوريدpvc لدراسة تغير مورفولوجيا االغشية الليفية المجوفة مع عوامل تصنيع مختلفة ) تاثير دراسة المراد العامل وتغيير التشغيل عند تثبيتها يجب والتي المؤثرة للعوامل معقولة بداية نقطة وإعطاء تغييره على االغشية. النفاذية المجوفة, انقالب الطور, عملية الترشيح, البوليمر الكلمات الدالة: االغشية available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.23 no.4 (december 2022) 81 – 90 eissn: 2618-0707, pissn: 1997-4884 corresponding author: name: ameen k. salih, email: ameen.salih2008m@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. artificial intelligent models for detection and prediction of lost circulation events: a review ameen k. saliha, b and hassan a. abdul husseina a petroleum engineering department, college of engineering, university of baghdad, baghdad, iraq b petroleum technology department, university of technology, baghdad, iraq abstract lost circulation or losses in drilling fluid is one of the most important problems in the oil and gas industry, and it appeared at the beginning of this industry, which caused many problems during the drilling process, which may lead to closing the well and stopping the drilling process. the drilling muds are relatively expensive, especially the muds that contain oil-based mud or that contain special additives, so it is not economically beneficial to waste and lose these muds. the treatment of drilling fluid losses is also somewhat expensive as a result of the wasted time that it caused, as well as the high cost of materials used in the treatment such as heavy materials, cement, and others. the best way to deal with drilling fluid losses is to prevent them. drilling fluid loss is a complex problem that is difficult to predict using simple and traditional methods. artificial intelligence represents a modern and accurate technology for solving complex problems such as drilling fluid loss. artificial intelligence through supervised machine learning provides the possibility of predicting these losses before they occur based on field data such as drilling fluid properties, drilling parameters, rock properties, and geomechanical parameters that are related to the loss of circulation of the wells suffered from losses problem located in the same area. in this paper, several supervised machine learning models have been reviewed that were used for detecting and predicting of loss of drilling fluids during the drilling process. the paper provides an inclusive review of drilling fluid prediction and detection from simplest to more complected intelligent models. keywords: artificial intelligence, machine learning, lost circulation prediction, intelligent models, loss of circulation. received on 11/06/2022, accepted on 27/07/2022, published on 30/12/2022 https://doi.org/10.31699/ijcpe.2022.4.10 1introduction drilling fluid loss is a common problem in the petroleum industry. loss of drilling mud totally or partially within a formation during the drilling process or the return mud from the well is not equivalent to the mud injected into the well is called drilling fluid loss or return loss [1]. loss of circulation usually happens in highly permeable, depleted reservoirs, natural fissures, cavernous, and fracture formations as shown in fig. 1 [2]. the loss of drilling fluid leads to an increase in the lost time, which is known as nonproductive time npt, which is the time needed to treat this problem [3]. during this time, the drilling process stops, which causes a loss of time and an increase in the cost of drilling. fig. 2 represents causes of delays in drilling time at five sets offshore wells in the gulf of mexico. this problem is one of the costliest problems in the oil industry, as it costs 2$ billion annually to treat it also, represents (12% of npt) according to worldwide oil industry estimation and (46% of npt) in the rumaila oil field [3]. failure to treat the loss of drilling fluid and restore the drilling process normally can lead to stuck pipe or in the worst case to closing the well [4]. there are several methods used to control the loss of circulation. the first one is done by minimizing the density of the drilling mud [5]. the second method is done by using lost circulation materials (lcm) such as peanut shells, mica, cellophane, calcium carbonate, and polymeric materials to bridge over and seal loss zones [5]. these methods are too expensive and time consumption. many factors that affecting the loss of drilling fluid, including the petrophysical properties of the rocks (porosity, permeability, etc.) and the properties of the drilling fluid itself (mw, ecd, yp, pv, etc.), as well as the drilling parameters (rop, wob, rpm, spm, ssp, tfa, etc.) in addition to (pore pressure gradient, fracture pressure, etc.) these are some of the well-known factors and there are other unknown factors [6]. controlling these factors to prevent the loss of drilling fluid is a very difficult task, so it is necessary to have a smart model to predict the occurrence of losses or not, as well as to predict the type of those losses depending on these factors, and therefore some of these factors that can be controlled to prevent or reduce the loss of drilling fluid [7]. artificial intelligence is one of the most important techniques used in solving complex problems by revealing patterns and complex relationships between the http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:ameen.salih2008m@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2022.4.10 a. k. salih and h. a. abdul hussein / iraqi journal of chemical and petroleum engineering 23,4 (2022) 81 90 82 causes of the problem and the outcome [8]. several intelligent models to predict loss of circulation were developed because of the high treatment cost of the losses. prior to the development of these smart models, the prediction did not provide additional benefits as compared to detection [8, 9]. fig. 1. various lost circulation zone types [2] fig. 2. days required to treat drilling problems for five sets of offshore wells [10] a. k. salih and h. a. abdul hussein / iraqi journal of chemical and petroleum engineering 23,4 (2022) 81 90 83 2overview of prevention of lost circulation problem the process of compiling the papers related to this topic was divided into three parts, a section that included the compilation of all the papers related to this title represents the first part, and the other part included dividing the papers into prediction and detection, and the last part was to enter deeply into building the models, the data used, and the accuracy of these models as shown in fig. 3. fig. 3. scheme showing the methodology of preparing the research 3loss of circulation prediction review preventing lost circulation with good planning is a very useful way to stop lost circulation before it happens. lost recycling prevents lower costs than any other procedure for addressing losses after the fact. especially with expensive mud like oil-base mud, where it is not economically wise to lose such mud [11]. in this section, models that are used to predict drilling fluid losses will be discussed. moazzenii et al. (2010) multilayer feed_forward network learned by backpropagation was developed to predict loss circulation events in maroun oil field, asmari formation based on drilling reports (d.d.r) of 32 drilled wells fig. 4. the structure of the network consisted input layer with a dimension of 18, a hidden layer with 30 neurons, and a target with a dimension of 1. the result of this network with respect to linear correlation coefficient (r) for training, testing, and validation respectively 0.95, 0.76, and 0.82. the result of the network was good in low mud loss but it is bad in severe losses fig. 5 [6]. jahanbakhshi et al. (2014) a multilayer perceptron model developed to predict drilling fluid losses and show the effect of geomechanical parameters such as (minimum horizontal stress, uniaxial compressive strength, young module, tensile strength, etc.) on the losses. they built two models for these goals, the first one was developed depending on nongeomechanical parameters such as (drilling fluid properties, drilling parameters, pressures, etc.) only and the other one was created depending on both geomechanical and nongeomechanical parameters. the result shows that the model included geomechanical parameters and was able to predict the losses better than the other one at high accuracy and low error fig. 6. the linear correlation coefficient (r) for the first and second models respectively was 0.75 and 0.94 [12]. toreifi et al. (2014) two modular neural network (mnn) models were built to predict the loss of circulation and a particle swarm optimization (pso) algorithm was used to optimize different parameters of drilling to reduce the losses. the accuracy of the prediction of the modular neural network models was 94% and 98% respectively. fig. 7 and fig. 8 show the two mnn models performance in the prediction loss of circulation [7]. aljubran et al. (2017) developed several ml and dl models to predict loss of circulation such as (rf, ann, cnn, and lstm). the data was drilling parameters gathered from 200 wells suffering from severe or total losses. these data are spilt into 80%,10%, and 10% to train, test and validation the models. the result showed that the cnn model was the best one and this model was able to detect signs leading to seepage and partial losses correctly table 1 [13]. sabah et al. (2019) developed several smart systems (mlp, rbf, ga-mlp, dt, anfis) to predict loss of circulation in the maroun oil field. the data was gathered from 61 recently drilled wells for training, testing, and implementing these models. the results show that dt is the best model used for prediction with (r) of 0.9034 and (rmse) of 0.091 table 2 [14]. fig. 4. maroun oilfield, south west of iran [6] a. k. salih and h. a. abdul hussein / iraqi journal of chemical and petroleum engineering 23,4 (2022) 81 90 84 fig. 5. predicted and real mud losses in maroun oil field [6] table 1. model’s results algorithm test accuracy (%) validation accuracy (%) rf (standard normalization) 80.96 78.50 ann (standard normalization) 89.15 78.17 rf (window normalization) 88.40 80.67 ann (window normalization) 90.74 79.39 cnn (window normalization) 92.55 82.33 lstm (window normalization) 92.45 87.64 table 2. performance indices model data set r2 rmse decision tree train test 0.97 0.93 0.052 0.091 mlp train test 0.92 0.90 0.094 0.099 anfis train test 0.90 0.88 0.1163 0.1087 rbf train test 0.85 0.84 0.1172 0.1315 ga-mlp train test 0.83 0.84 0.132 0.137 abbas et al. (2019) two intelligent models were developed to predict loss of circulation in southern iraqi oil fields. the data used to train, test, and implement these two models were collected from wells well in the southern oil fields of iraq. the first model was a support vector machine (svm) show good results than the second one which was ann. the accuracy of svm was 92% & 91% of training and testing respectively [8]. geng et al. (2019) applied machine learning algorithms to correlate the losses risk with the seismic data. support vector machine, logistic regression, and random forest were used to predict loss of circulation events by using seismic data. predictive results showed the crossvalidation accuracy of 0.8 which was a satisfactory outcome [9]. alkinani et al. (2019) artificial neural networks (anns) were developed to estimate losses in induced fracture formations. the data used to build this model was drilling operation parameters and drilling fluid properties collected from 1500 wells and divided into 60%, 20%, and 20% to train, test, and implement the model. the result showed that the best algorithm to train the ann was levenberg-marquardt (lm) which gives better accuracy with r2 equal to 0.92 [15]. agin et al. (2019) developed adaptive neuro fuzzy inference system (anfis) to predict the losses of drilling fluid in the maroun oilfield based on drilling data such as drilling operation parameters, drilling fluid properties, and amount of lost circulation. the result shows the root mean square error of anfis of training, testing, and validation equal to 0.08, 0.09, and 0.15 respectively. the results suggest that the anfis method can be successfully applied to establish a lost circulation prediction model fig. 9 [16]. hou et al. (2020) ann model was built to predict the loss of circulation in yingqiong basin one of the offshore hthp regions in the world. the data used for training and testing the model were drilling parameters, drilling fluid properties, and formation properties. the model was created to predict six types of losses (micro, small, middle, large, severe, and no losses). the accuracy after the 50-epoch iterative process was 93% and 92% for the training and testing respectively. the performance of the ann to predict six lost circulation types is good. the proposed model satisfies the need for drilling engineering and can provide guidance for the estimation of lost circulation risks prior to drilling [17]. ahmed et al. (2020) three artificial intelligence techniques developed (artificial neural network ann, fuzzy logic fl, and functional network fn) to predict the losses in high-pressure, high-temperature (hpht) wells. they used three wells in this work well a to train and test the models and well b and c to implement these models. drilling parameters are used to build these models. ann was the better model with a correlation coefficient of 0.99 and rmse 0.05 and was able to predict the lost circulation zones in the unseen wells [18]. a. k. salih and h. a. abdul hussein / iraqi journal of chemical and petroleum engineering 23,4 (2022) 81 90 85 fig. 6. comparative plot of ann performance [12] fig. 7. comparison of the estimated values of the first model and the real losses [7] fig. 8. comparison of the estimated values of the second model and the real losses [7] a. k. salih and h. a. abdul hussein / iraqi journal of chemical and petroleum engineering 23,4 (2022) 81 90 86 fig. 9. comparison of real and anfis outputs in checking data [16] 4loss of circulation detection review the methods or technology used for loss circulation detection are divided into two types the first one is called conventional and the second called intelligent methods. conventional methods include (pit volume monitoring, delta flow, etc.). there are other tools used for this target like (survey tools, pwd tools, and geostatistics-based). in this section, we will focus on the intelligent method which is most useful and has fewer errors than humans. yamaliev et al. (2009) developed deep drilling equipment technical condition recognition system is based on the images classification acting to the neural network that helped to understand and identify bit technological conditions based on pressure and bit weight which can help to improve drilling efficiency and solve any problems that can happen in the future fig. 10 [19]. lian z. et al. (2010) developed a fuzzy reasoning method to estimate the downhole conditions and monitor the control parameters which subsequently assisted in improving the drilling efficiency [20]. zhao j. et al. (2017) developed an unsupervised ml method such as (sax, hierarchical clustering, dynamic time warping, pattern recognition, and classification) for detecting various drilling anomalies depending on drilling data. this method can automatically inform the driller or remote center of the changes of operational parameters when unusual drilling events occur using drilling data to build the model such as bottom hole parameters, rheological properties, and geometric data of the well to predict various drilling anomalies (pipe stuck, change in ecd, fluid losses, etc.) [21]. unrau and torrione (2017) developed supervised ml models such as (support vector machines, regression models, etc.) these models help in checking for the false alarm and that’s will help incorrect detection of fluid losses or gain during the drilling process [22]. fig. 10. the neural network variant of the deep drilling equipment table 3. summary of detection studies no. the author objective of the study model inputs model structure outputs performance 1 yamaliev et al. (2009) understanding and identifying bit conditions neural networks dispersion, entropy, jinny coefficient, and spectrum 4-4-1 describe bit status 2 lian et al. (2010) estimating the downhole conditions fuzzy reasoning logging data such as: total hc, total pit volume, temperature, conduction, density, hook load - detecting of various drilling problems the application results of some cases showed accurate and reliable result 3 zhao j. et al. (2017) detecting of several drilling anomalies un-supervised ml hole parameters, rheological properties, and geometric properties of the well - pipe stuck, change in ecd, fluid losses, etc. this method used to inform the driller any change of drilling operational parameters when drilling events occur. 4 unrau and torrione (2017) checking for false alarm supervised ml models such as (support vector machine, regression models, etc.) pit volume, flowing in, flowing out accurate alarm of fluid losses the result was satisfactory a. k. salih and h. a. abdul hussein / iraqi journal of chemical and petroleum engineering 23,4 (2022) 81 90 87 table 4. summary of prediction studies no. the author objective of the study model inputs model structure outputs performance 1 moazzani et al. (2010) prediction of lost circulation ann well depth, pump flow rate, pump pressure, bit size, mud weight, solids content, phi600, phi300, drilling time, volume loss, physical properties of the rocks 18-30-1 losses r2 of ann model 0.95, 0.82, 0.76 for training, testing and validation respectively 2 jahanbekhshi et al. (2014) prediction of lost circulation ann non-geomechanical: hole deepness, ϕ, permeability, ssp, ecd, pv, gel strength, viscosity, solids content, temperature. geomechanical: tensile strength, uniaxial strength, horizontal stress, e-modulus 11-15-1 16-1-9-1 losses r2 are 0.75 and 0.94 for models 1 and 2 3 toreifi et al. (2014) prediction of lost circulation mnnpso depth, top of the formation, ssp, type of the formation, pump flow rate, rop, pump pressure, solids content, plastic viscosity, gel strength, annuls volume, ϒp / losses r2 is 0.944 and mse is 0.0047 4 aljubran et al. (2017) prediction of lost circulation rf, cnn, ann, lstm surface drilling parameters: wob, hkht, hkl, tq, spp, flwin, flwout, rop, rpm, pvt. cnn 16-4 losses cnn was the best model with an accuracy of 92.55% 5 sabah et al. ( 2019 ) prediction of loss circulation anfis, dt, mlpnn, rbf-nn and ga-mlp hole diameter and depth, pp, ffp, mud pressure, rop, cp, solid content, wob, pv, rpm, ϒp, mud viscosity, gel 10 min, gel strength, md, hole diameter, ssp, phi600, phi300, mud rate anfis: 28 -measurable functions -normalization defuzzification final outputs mlpnn: single layer input and output rbfnn: one layer for input, output, and hidden. mlp-ga: input-1010-1 losses dt was the best with (r2) of 0.935and (rmse) of 0.091 6 abbas a. et al.(2019) prediction of lost circulation svm and ann lithology, mud weight, pump rate, rop, cp, solid content, wob, pv, rpm, ϒp, mud viscosity, gel 10 min, gel strength, md, hole diameter ann: 18-40-40-1 losses ann training and testing accuracy are 0.87 and 0.83 7 geng z. et al. (2019) prediction of loss circulation using seismics data lrc, rfc, and svc variance, sweetness, attenuation, and rms amplitude detecting fluid loss hazard cross-validation accuracy 0.8 8 alkinani et al. (2019) prediction of lost circulation ann mw, wob, ϒp, pv, tfa, ecd, pump flow rate 1-10-1 volume of losses r2 equal 0.925 9 agin et al. (2019) prediction of lost circulation anfis drilling footage, hole size, wob, rpm, pump rate, pump pressure, pv, θ600, θ300, solid percent, mud velocity, pore pressure, gel strength, drilling time, ssp, losses anfis: -17 inputs -measurable functions 12 if-then fuzzy -output of 12 clusters -final outputs losses rmse of anfis 0.08,0.09 and 0.15 of training, testing, and validation respectively 10 hou et al. (2020) prediction of lost circulation ann drilling fluid properties: mw, yp, pv, solid content drilling operation parameters: pump rate, rpm, rop, wob, spp, tfa, md geology parameters: lithology 15-(6-15)6 six lost circulation types ann accuracy 93% and 92% of training and testing 11 ahmed et al. (2020) loss circulation prediction binary classification fn, fl, and ann depth, hkht, hkl, fpwpmp, rop, rpm, spp, torque, wob ann: 6-5-2 losses ann is the best model with r 0.99 and rmse 0.05 a. k. salih and h. a. abdul hussein / iraqi journal of chemical and petroleum engineering 23,4 (2022) 81 90 88 5conclusion the problem of losing drilling fluid is a difficult and complex problem that is difficult to detect easily and costs the oil industry a lot of money, and it is difficult to predict using traditional techniques until after it occurs. modern technologies such as artificial intelligence have provided a great service to the oil industry in predicting cases of drilling fluid loss, thus this problem can be avoided using these techniques, and that lead to reduce npt, costs incurred to treat this problem, and increased drilling efficiency. it is clear by reviewing these techniques that there is no specific technique to solve this problem. if we assume that one of the techniques works perfectly in a certain area, it works horribly in another area. several smart models have been reviewed, most of the models are built based on the properties of the drilling fluid (mud weight, plastic viscosity, yield point, etc.), and drilling parameters (pressure, weight on bit, rate of penetration, etc.) without the petrophysical properties of the rocks (porosity, permeability, etc.) due to the difficulty of obtaining them in the area where the drilling fluid losses occur. the accuracy of the model depends on the accuracy of the obtained data and its relevance to the problem, and the selection of data depends on experience to the greatest extent. the models in which rock properties are used showed higher accuracy than other models. depending on the study, the most important parameter influencing the drilling fluid loss process which was drilling fluid properties such as equivalent circulating density (ecd) that means the possibility of preventing or reducing the possibility of this problem occurring by controlling the value of the most important factors causing this problem. moreover, these techniques require a lot of time and data for the purpose of developing them, as most of these techniques discover all kinds of problems during the drilling process, which makes determining the main cause of these problems difficult. nomenclature acronym definition ai artificial intelligence anfis adaptive neuro fuzzy interface system ann artificial neural networks cnn convolutional neural networks fn functional networks fl functional language mlp multi-layer perceptron hkht hook height ga-mlp genetic algorithm multilayer perceptron lrc logistic regression classifier lstm long short-term memory mlp multilayer perceptron mlp-nn multilayer perceptron neural network mse mean-square error md measure depth mnn modular-neural network npt non-production time pv plastic viscosity pso particle swarm optimization r linear correlation coefficient r2 square linear correlation coefficient rbf radial basis function rf random forest rfc random forest classification rps round per seconds rmse root mean square error svc support vector machine classification svm support vector machine references [1] c. r. miranda, et al. "materials for controlling severe lost circulation-laboratory evaluation," spe latin america and caribbean petroleum engineering conference, onepetro, 2017. [2] s. krishna, s. ridha, p. vasant, s. ilyas and a. sophian, "conventional and intelligent models for detection and prediction of fluid loss events during drilling operations: a comprehensive review", journal of petroleum science and engineering, vol. 195, p. 107818, 2020. [3] u. arshad et al., "engineered solution to reduce the impact of lost circulation during drilling and cementing in rumaila field, iraq", day 4 wed, december 09, 2015, 2015. [4] n. said amin and a. a.alhaleem, "analysis of stuck pipe incidents in khabaz field", iraqi journal of chemical and petroleum engineering, vol. 19, no. 4, pp. 47-53, 2018. [5] d. e. caughron, d. k. renfrow and j. r. bruton et al., "unique crosslinking pill in tandem with fracture prediction model cures circulation losses in deepwater gulf of mexico." iadc/spe drilling conference, 2002. [6] a. moazzeni, m. nabaei, k. shahbazi and a. shadravan, "mechanical earth modeling improves drilling efficiency and reduces non-productive time (npt)." spe deep gas conference and exhibition, manama, bahrain, january 2010. [7] h. toreifi, h. rostami and a. manshad, "new method for prediction and solving the problem of drilling fluid loss using modular neural network and particle swarm optimization algorithm", journal of petroleum exploration and production technology, vol. 4, no. 4, pp. 371-379, 2014. [8] a. abbas, a. bashikh, h. abbas and h. mohammed, "intelligent decisions to stop or mitigate lost circulation based on machine learning", energy, vol. 183, pp. 1104-1113, 2019. [9] z. geng et al., "predicting seismic-based risk of lost circulation using machine learning", journal of petroleum science and engineering, vol. 176, pp. 679-688, 2019. https://onepetro.org/spelacp/proceedings-abstract/17lacp/2-17lacp/d021s010r004/194703 https://onepetro.org/spelacp/proceedings-abstract/17lacp/2-17lacp/d021s010r004/194703 https://onepetro.org/spelacp/proceedings-abstract/17lacp/2-17lacp/d021s010r004/194703 https://onepetro.org/spelacp/proceedings-abstract/17lacp/2-17lacp/d021s010r004/194703 https://www.sciencedirect.com/science/article/abs/pii/s0920410520308792 https://www.sciencedirect.com/science/article/abs/pii/s0920410520308792 https://www.sciencedirect.com/science/article/abs/pii/s0920410520308792 https://www.sciencedirect.com/science/article/abs/pii/s0920410520308792 https://www.sciencedirect.com/science/article/abs/pii/s0920410520308792 https://www.sciencedirect.com/science/article/abs/pii/s0920410520308792 https://onepetro.org/iptconf/proceedings-abstract/15iptc/4-15iptc/d041s038r001/153565 https://onepetro.org/iptconf/proceedings-abstract/15iptc/4-15iptc/d041s038r001/153565 https://onepetro.org/iptconf/proceedings-abstract/15iptc/4-15iptc/d041s038r001/153565 https://onepetro.org/iptconf/proceedings-abstract/15iptc/4-15iptc/d041s038r001/153565 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/508 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/508 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/508 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/508 https://onepetro.org/spedc/proceedings-abstract/02dc/all-02dc/spe-74518-ms/136928 https://onepetro.org/spedc/proceedings-abstract/02dc/all-02dc/spe-74518-ms/136928 https://onepetro.org/spedc/proceedings-abstract/02dc/all-02dc/spe-74518-ms/136928 https://onepetro.org/spedc/proceedings-abstract/02dc/all-02dc/spe-74518-ms/136928 https://onepetro.org/spedc/proceedings-abstract/02dc/all-02dc/spe-74518-ms/136928 https://onepetro.org/spedgas/proceedings-abstract/10dgas/all-10dgas/spe-131718-ms/106195 https://onepetro.org/spedgas/proceedings-abstract/10dgas/all-10dgas/spe-131718-ms/106195 https://onepetro.org/spedgas/proceedings-abstract/10dgas/all-10dgas/spe-131718-ms/106195 https://onepetro.org/spedgas/proceedings-abstract/10dgas/all-10dgas/spe-131718-ms/106195 https://onepetro.org/spedgas/proceedings-abstract/10dgas/all-10dgas/spe-131718-ms/106195 https://link.springer.com/article/10.1007/s13202-014-0102-5 https://link.springer.com/article/10.1007/s13202-014-0102-5 https://link.springer.com/article/10.1007/s13202-014-0102-5 https://link.springer.com/article/10.1007/s13202-014-0102-5 https://link.springer.com/article/10.1007/s13202-014-0102-5 https://link.springer.com/article/10.1007/s13202-014-0102-5 https://www.sciencedirect.com/science/article/abs/pii/s0360544219313477 https://www.sciencedirect.com/science/article/abs/pii/s0360544219313477 https://www.sciencedirect.com/science/article/abs/pii/s0360544219313477 https://www.sciencedirect.com/science/article/abs/pii/s0360544219313477 https://www.sciencedirect.com/science/article/abs/pii/s0920410519301032 https://www.sciencedirect.com/science/article/abs/pii/s0920410519301032 https://www.sciencedirect.com/science/article/abs/pii/s0920410519301032 https://www.sciencedirect.com/science/article/abs/pii/s0920410519301032 a. k. salih and h. a. abdul hussein / iraqi journal of chemical and petroleum engineering 23,4 (2022) 81 90 89 [10] w. white, causes of delays in drilling time with use of wbms at five offshore wells representing 871 drilling days. technical report, marathon oil, lafayette, la, usa. 1994. [11] g. fuh, n. morita, p. boyd and s. mcgoffin, "a new approach to preventing lost circulation while drilling." spe annual technical conference and exhibition, washington, d.c., 1992. [12] r. jahanbakhshi, r. keshavarzi and s. jalili, "artificial neural network-based prediction and geomechanical analysis of lost circulation in naturally fractured reservoirs: a case study", european journal of environmental and civil engineering, vol. 18, no. 3, pp. 320335, 2013. [13] m. aljubran, j. ramasamy, m. albassam and a. magana-mora, "deep learning and time-series analysis for the early detection of lost circulation incidents during drilling operations", ieee access, vol. 9, pp. 76833-76846, 2021. [14] m. sabah, m. talebkeikhah, f. agin, f. talebkeikhah and e. hasheminasab, "application of decision tree, artificial neural networks, and adaptive neuro-fuzzy inference system on predicting lost circulation: a case study from marun oil field", journal of petroleum science and engineering, vol. 177, pp. 236-249, 2019. [15] alkinani, husam h., al-hameedi, abo taleb, dunnnorman, shari, alkhamis, mohammed m., and rusul a. mutar, "prediction of lost circulation prior to drilling for induced fractures formations using artificial neural networks." paper presented at the spe oklahoma city oil and gas symposium, oklahoma city, oklahoma, usa, april 2019. [16] f. agin, r. khosravanian, m. karimifard and a. jahanshahi, "application of adaptive neuro-fuzzy inference system and data mining approach to predict lost circulation using doe technique (case study: maroon oilfield)", petroleum, vol. 6, no. 4, pp. 423437, 2020. [17] x. hou et al. "lost circulation prediction in south china sea using machine learning and big data technology," offshore technology conference, houston, texas, usa, may 2020. [18] a. ahmed, s. elkatatny, a. ali, m. abughaban and a. abdulraheem, "application of artificial intelligence techniques in predicting the lost circulation zones using drilling sensors", journal of sensors, vol. 2020, pp. 1-18, 2020. [19] v. yamaliev, e. imaeva and t. salakhov, "about the deep drilling equipment technical condition recognition method", ufa state pet. technol. univ., 2009. [20] z. lian, y. zhou, q. zhau and z. huo, "a study on drilling risk real time recognition technology based on fuzzy reasoning." in int. oil gas conf. exhib, china, 2010. [21] zhao, jie, shen, yuelin, chen, wei, zhang, zhengxin, and sonny johnston,"machine learning– based trigger detection of drilling events based on drilling data." spe eastern regional meeting, lexington, kentucky, usa, october 2017. [22] s. unrau, and p. torrione, "adaptive real-time machine learning-based alarm system for influx and loss detection." spe annual technical conference and exhibition, san antonio, texas, usa, october 2017. https://onepetro.org/speatce/proceedings-abstract/92spe/all-92spe/spe-24599-ms/53880 https://onepetro.org/speatce/proceedings-abstract/92spe/all-92spe/spe-24599-ms/53880 https://onepetro.org/speatce/proceedings-abstract/92spe/all-92spe/spe-24599-ms/53880 https://onepetro.org/speatce/proceedings-abstract/92spe/all-92spe/spe-24599-ms/53880 https://www.tandfonline.com/doi/abs/10.1080/19648189.2013.860924 https://www.tandfonline.com/doi/abs/10.1080/19648189.2013.860924 https://www.tandfonline.com/doi/abs/10.1080/19648189.2013.860924 https://www.tandfonline.com/doi/abs/10.1080/19648189.2013.860924 https://www.tandfonline.com/doi/abs/10.1080/19648189.2013.860924 https://www.tandfonline.com/doi/abs/10.1080/19648189.2013.860924 https://ieeexplore.ieee.org/abstract/document/9438672/ https://ieeexplore.ieee.org/abstract/document/9438672/ https://ieeexplore.ieee.org/abstract/document/9438672/ https://ieeexplore.ieee.org/abstract/document/9438672/ https://ieeexplore.ieee.org/abstract/document/9438672/ https://www.sciencedirect.com/science/article/abs/pii/s0920410519301822 https://www.sciencedirect.com/science/article/abs/pii/s0920410519301822 https://www.sciencedirect.com/science/article/abs/pii/s0920410519301822 https://www.sciencedirect.com/science/article/abs/pii/s0920410519301822 https://www.sciencedirect.com/science/article/abs/pii/s0920410519301822 https://www.sciencedirect.com/science/article/abs/pii/s0920410519301822 https://www.sciencedirect.com/science/article/abs/pii/s0920410519301822 https://onepetro.org/speokog/proceedings-abstract/19okog/2-19okog/d021s008r001/219854 https://onepetro.org/speokog/proceedings-abstract/19okog/2-19okog/d021s008r001/219854 https://onepetro.org/speokog/proceedings-abstract/19okog/2-19okog/d021s008r001/219854 https://onepetro.org/speokog/proceedings-abstract/19okog/2-19okog/d021s008r001/219854 https://onepetro.org/speokog/proceedings-abstract/19okog/2-19okog/d021s008r001/219854 https://onepetro.org/speokog/proceedings-abstract/19okog/2-19okog/d021s008r001/219854 https://onepetro.org/speokog/proceedings-abstract/19okog/2-19okog/d021s008r001/219854 https://www.sciencedirect.com/science/article/pii/s2405656118300531 https://www.sciencedirect.com/science/article/pii/s2405656118300531 https://www.sciencedirect.com/science/article/pii/s2405656118300531 https://www.sciencedirect.com/science/article/pii/s2405656118300531 https://www.sciencedirect.com/science/article/pii/s2405656118300531 https://www.sciencedirect.com/science/article/pii/s2405656118300531 https://onepetro.org/otconf/proceedings-abstract/20otc/4-20otc/d041s053r005/107333 https://onepetro.org/otconf/proceedings-abstract/20otc/4-20otc/d041s053r005/107333 https://onepetro.org/otconf/proceedings-abstract/20otc/4-20otc/d041s053r005/107333 https://onepetro.org/otconf/proceedings-abstract/20otc/4-20otc/d041s053r005/107333 https://www.hindawi.com/journals/js/2020/8851065/ https://www.hindawi.com/journals/js/2020/8851065/ https://www.hindawi.com/journals/js/2020/8851065/ https://www.hindawi.com/journals/js/2020/8851065/ https://www.hindawi.com/journals/js/2020/8851065/ https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=75dca019357c4c6da3e93cd7c450ea04856014f8 https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=75dca019357c4c6da3e93cd7c450ea04856014f8 https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=75dca019357c4c6da3e93cd7c450ea04856014f8 https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=75dca019357c4c6da3e93cd7c450ea04856014f8 https://onepetro.org/speiogcec/proceedings-abstract/10iogcec/all-10iogcec/spe-131886-ms/107021 https://onepetro.org/speiogcec/proceedings-abstract/10iogcec/all-10iogcec/spe-131886-ms/107021 https://onepetro.org/speiogcec/proceedings-abstract/10iogcec/all-10iogcec/spe-131886-ms/107021 https://onepetro.org/speiogcec/proceedings-abstract/10iogcec/all-10iogcec/spe-131886-ms/107021 https://onepetro.org/speerm/proceedings-abstract/17erm/2-17erm/d023s001r005/194913 https://onepetro.org/speerm/proceedings-abstract/17erm/2-17erm/d023s001r005/194913 https://onepetro.org/speerm/proceedings-abstract/17erm/2-17erm/d023s001r005/194913 https://onepetro.org/speerm/proceedings-abstract/17erm/2-17erm/d023s001r005/194913 https://onepetro.org/speerm/proceedings-abstract/17erm/2-17erm/d023s001r005/194913 https://onepetro.org/speatce/proceedings-abstract/17atce/3-17atce/d031s033r005/193185 https://onepetro.org/speatce/proceedings-abstract/17atce/3-17atce/d031s033r005/193185 https://onepetro.org/speatce/proceedings-abstract/17atce/3-17atce/d031s033r005/193185 https://onepetro.org/speatce/proceedings-abstract/17atce/3-17atce/d031s033r005/193185 https://onepetro.org/speatce/proceedings-abstract/17atce/3-17atce/d031s033r005/193185 https://onepetro.org/speatce/proceedings-abstract/17atce/3-17atce/d031s033r005/193185 a. k. salih and h. a. abdul hussein / iraqi journal of chemical and petroleum engineering 23,4 (2022) 81 90 90 : مراجعةسائل الحفر نماذج ذكية للكشف والتنبؤ بأحداث فقدان حسن عبد الهادي عبد الحسين 1 و امين كريم صالح 2، 1 جامعة بغداد، بغداد، العراقكلية الهندسة، ، نفطقسم هندسة ال 1 العراق ،بغداد ،الجامعة التكنولوجية ،قسم تكنولوجيا النفط 2 الخالصة ه ، وظهر في بداية هذزهم المشاكل في صناعة النفط والغافي سائل الحفر من أ الفقدان اوالنقصانيعد ملية عالصناعة، مما تسبب في العديد من المشاكل أثناء عملية الحفر، والتي قد تؤدي إلى إغالق البئر ووقف ت أو الذي يحتوي على إضافا نفطالحفر. إن طين الحفر غالي الثمن نسبًيا، خاصًة الطين الذي يحتوي على باهظة وفقدانها. كما أن معالجة خسائر سوائل الحفر طيانه األخاصة، لذلك فهو غير مفيد اقتصادًيا إهدار هذ الجة ي المعالثمن إلى حد ما نتيجة للوقت الضائع الذي تسبب فيه، فضاًل عن التكلفة العالية للمواد المستخدمة ف لذكاء . يوفر احدوثها هو منع طريقة للتعامل مع فقد سائل الحفرواألسمنت وغيرها. أفضل المثقلةمثل المواد ى االصطناعي من خالل التعلم اآللي الخاضع لإلشراف إمكانية التنبؤ بهذه الخسائر قبل حدوثها بناًء عل ية البيانات الميدانية مثل خصائص سائل الحفر، ومعايير الحفر، وخصائص الصخور، والمعايير الجيوميكانيك المنطقة. اآلبار التي عانت من مشكلة الخسائر الموجودة في نفسبالمتعلقة لكشف في هذا البحث، تمت مراجعة العديد من نماذج التعلم اآللي الخاضعة لإلشراف والتي تم استخدامها ل شافه من ر واكتعن فقدان سوائل الحفر والتنبؤ به أثناء عملية الحفر. تقدم الورقة مراجعة شاملة للتنبؤ بسائل الحف النماذج الذكية األبسط إلى األكثر تجميًعا. ., مشاكل عملية الحفر, نموذج ذكي, اطيان الحفرصطناعي, خسارة سائل الحفر, التنبؤالكلمات الدالة: الذكاء اال available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.23 no.1 (march 2022) 23 – 29 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: amenah s. al-nuaimi, email: am.sa91@yahoo.com , name: muthanna j. ahmed, email: muthanna@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. catalytic conversion of glucose into 5-hydroxymethyl furfural over spent dry batteries as catalysts amenah s. al-nuaimi and muthanna j. ahmed chemical engineering department/university of baghdad/baghdad, iraq abstract biomass is a popular renewable carbon source because it has a lot of potential as a substitute for scarce fossil fuels and has been used to make essential compounds like 5-hydroxymethylfurfural (hmf). one of the main components of biomass, glucose, has been extensively studied as a precursor for the production of hmf. several efforts have been made to find efficient and repeatable procedures for the synthesis of hmf, a chemical platform used in the manufacturing of fuels and other high-value compounds. sulfonated graphite (sg) was produced from spent dry batteries and utilized as a catalyst to convert glucose to 5hydroxymethylfurfural (hmf). temperature, reaction time, and catalyst loading were the variables studied. when dimethyl sulfoxide was utilized as the solvent at 180°c after 3 hours of reaction time, the greatest hmf yield, glucose conversion, and selectivity were attained, with 56.53 %, 97.5 %, and 57.979 %, respectively. this study demonstrates how to manufacture sulfonated graphite with increased catalytic activity for converting glucose to key biobased platform chemicals in a long-term sustainable manner. keywords: biomass, 5-hydroxymethylfurfural (hmf), glucose conversion. received on 03/02/2022, accepted on 13/03/2022, published on 30/03/2022 https://doi.org/10.31699/ijcpe.2022.1.4 1introduction without a doubt, one of civilization's most basic requirements, energy, must be readily available. energy underpins pillars of modern society such as technical advancement, scientific achievement, and cultural advancement. conventional fossil fuels such as petroleum, coal, and natural gas are currently the primary sources of energy and chemicals. fossil fuel is made up of organic materials that have been chemically changed over thousands of years by extreme heat and pressure. petroleum is used to make nearly 95 % of chemicals, in addition to being a source of energy and fuel [1]. as the world's population grows and living standards rise, the need for energy and chemicals rises as well. however, fossil fuels, such as petroleum, have a finite supply and will not be able to provide the world's energy needs indefinitely [2]. instead of refining petroleum to generate hydrocarbons derivatives like liberates, fuels, and chemicals, we may refine renewable (wood, municipal and industrial wastewater, agriculture, and paper wastes) into fuel. sugars are raw materials for a variety of products, including bioplastics, ethanol, citric acid, and other compounds. the need for energy has surged in recent years, resulting in increased oil prices. as costs rise, biomass-derived products become more cost-effective and environmentally friendly than fossil-fuel-derived products [3]. as a result, alternative energy, fuel, and chemical production sources and technologies must be developed to at least supplement current petroleum-based sources. biomass offers a possible alternative to petroleum as a renewable energy source. organic materials generated from live or recently living creatures are classified as biomass. solar, wind, geothermal, nuclear, and hydropower are examples of renewable alternative energy sources. even though none of the above resources can cover all of our future energy needs, the potential contribution of lignocellulosic biomass is enormous due to its widespread availability [4]. the annual global biomass production is predicted to be 170 billion metric tons. furthermore, biomass plays an important part in carbon balancing since co2 produced during usage can be offset by co2 fixation by plants during photosynthesis [5]. among the several methods for valorizing lignocellulosic biomass, catalytic dehydration of glucose to create 5-hydroxymethylfurfural (hmf) is a promising one. hmf (5-hydroxymethyl-2-furaldehyde, 5hydroxymethyl-2-furancarboxaldehyde) is a frequent chemical produced by heat treatment of carbohydratecontaining foods in the presence of amino acids [6]. dried fruits, coffees, cereals, and baking items all contain it naturally. 5-hydroxymethylfurfural (hmf), a five-member aromatic ring molecule with hydroxymethyl and aldehydefunctional groups, is widely used in the synthesis of medicines, polymers, fine chemicals, and other organic derivatives. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:am.sa91@yahoo.com mailto:muthanna@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2022.1.4 a. s. al-nuaimi and m. j. ahmed / iraqi journal of chemical and petroleum engineering 23,1 (2022) 23 29 24 hmf is made by dehydrating monosaccharides, disaccharides, and polysaccharides with an acid catalyst [7]. acid-catalyzed dehydration of c6 carbohydrates, such as fructose and glucose, is the preferred method for obtaining hmf. due to their availability and abundance in agricultural side streams and other wastes, glucosebased polymers, particularly those generated from lignocellulosic sources, are preferred feedstocks. the development of catalytic methods that can efficiently combine the complicated multi-step transformation processes involved in using biorenewable feedstock for the sustainable synthesis of hmf is of special interest [8]. hmf is a platform chemical made by removing triple water molecules from c6 carbohydrate in the presence of an acid catalyst [9]. the impact of acid treatments such as hcl, hf, and hno3 on the characteristics of a supported ac catalyst was discovered that acid treatment greatly affected the surface chemical characteristics of the ac and increased its surface area. it was thought that hno3 may oxidize certain complexes and produce acidic groups. surface acidity rises, resulting in a more homogeneous distribution on ac [10]. metal chlorides [11], mineral acids [12], carbon solid acids [13], ion exchange resin [14], zeolites [15], solid metal phosphates [16] and sulfated zirconias [17] have all been used as heterogeneous or homogeneous acid catalysts in this reaction. heterogeneous catalysts, in comparison to dissolving homogeneous acid catalysts, have various advantages, including the ability to be simply separated or recycled and the lack of equipment corrosion. solid acid catalysts also enable surface acidity adjustment and operation in harsh reaction conditions. for diverse carbohydrate conversions, various kinds of acid sites such as bronsted acid, lewis acid, and bifunctional acid were added onto solid catalyst [18]. using bronsted acid catalysts, fructose can be transformed to hmf in a step process. because the reaction is frequently a two-step process requiring the catalysts to have two types of active sites, the conversion of glucose to hmf is substantially more complex than the transformation of fructose to hmf [9]. catalytic reaction glucose isomerization to fructose in the presence of lewis acids, enzymes, or bases is the initial step. the second stage of fructose dehydration to hmf is driven by bronsted acids. fig. 1 shows the glucose conversion to 5-hydroxymethylfurfural. fig. 1. glucose conversion to 5-hydroxymethylfurfural (hmf) recent research reveals that under sufficient bronsted acidity, glucose can also be directly dehydrated to hmf, bypassing the glucose-fructose isomerization [19]. some solid acids treated with lewis acid sites or bronsted acid, on the other hand, release only small amounts of hmf [18]. strong bronsted acids produce significant hmf yields, but they also cause unwanted hmf degradation to humins [20] and levulinic acid [21]. dimethylsulfoxide (dmso) [22], water [23], tetrahydrofuran (thf) [17], methyl isobutyl ketone (mibk) [24], ionic liquids (ils) [25] and γ-valerolactone (gvl) [26], have all been studied as solvents to decrease the development of potential byproducts. many domestic items, such as wireless mice, digital cameras, toys, flashlights, clocks, and so on, use alkaline batteries as power sources [27]. aside from the batteries gathered from customers, factory-produced wasted batteries are a significant waste source that must not be overlooked. because each factory's annual production volume is typically over a hundred million pieces, the quantities of co-produced wasted batteries in the manufacturing lines are just too vast to be ignored [28]. alkaline batteries account for 68% of all battery sales in switzerland [29], 60% in the uk [30], and 47% in the eu [31], hence recycling spent batteries is critical for environmental safety, human health, and resource efficiency [27]. this work aims to convert glucose into 5hydroxymethyl furfural, preparation of catalyst from used dry batteries, and study the parameters that are effective on the glucose conversion, hmf yield and selectivity, the studied parameter are: temperature, time and catalytic loading were examined to get the optimum results. 2experimental work 2.1. materials without additional purification, all of the reagents were employed. dry batteries, d-glucose (99.5%), was provided by himedia laboratories pvt. ltd. (mumbai, india), 5-hydroxymethyl-2-furaldehyde (hmf, 98%, shanghai macklin biochemical co., ltd), sulfuric acid (h2so4, 98 wt%), dimethylsulphoxide (dmso, mumbai, 99%), hydrochloric acid (hcl, 36.5%), glycerine bath, throughout the studies, deionized water was used. 2.2. catalysts preparation the catalyst preparation procedure included two steps: graphite preparation and sulfonation of the graphite obtained. utilized dry batteries were used to make the graphite. we began by gathering the spent batteries and separating the cathode electrode (graphite rod) from the anode electrode. a. s. al-nuaimi and m. j. ahmed / iraqi journal of chemical and petroleum engineering 23,1 (2022) 23 29 25 the cathode electrode (graphite rod) was next grounded by a high-speed rotating having to cut machine, and finally through mesh sieve to yield tests to the desired particle size, before being rinsed with distilled water at ambient temperature and dried for 2 hours at 100 °c. sulfonation of graphite: 5 g of graphite samples (to get 5 grams of graphite, we need about 5 batteries because the weight of the graphite electrode for each battery is about =1.03) were placed in a three-necked round bottomed flask with a concentrated sulfuric acid solution (50 ml), the flask has been heated to 160 °c for 5 hours by a glycerine bath with magnetic stirring under reflux, as shown in fig. 2. the solids fraction were recovered by filtration and cleaned with deionized water to eliminate any impurities from the solid material after preserving a sulfonation reaction. the sulfonated samples were cleaned with distilled water many times until the ph of the filtrate was normal, then dried at 100°c for 2 hours. the resulting solid was labeled sg and stored in a desiccator until it was needed. fig. 2. photograph of the experimental system (1)magnetic stirrer (2)glycerine bath (3)thermometer (4)condenser (5)stand (6) three-necked round bottomed flask 2.3. characterization of catalyst surface area and pore volume measurements, brunsuer emmettteller (bet) and pore volume, according to 92772010 iso method was performed to measure the surface area and pore volume, country usa, thermo finnigan, device range (0.12000 m 2 /g), at petroleum r and d center (prdc) laboratory, ministry of oil/ iraq. 2.4. conversion of glucose to hmf 5 grams of glucose were combined with 50 ml dmso in a 100 ml three-necked round bottomed flask, then the appropriate amount of sg was added as a catalyst. after that, the reactor was immersed in a glycerine bath. the reaction conditions were as follows: the magnetic stirrer speed was 550 rpm, the temperature range was 120 to 200 °c, the time was 0.5 to 4 hours, the catalyst loading was 0.025 to 2.5 grams, and dmso as a solvent was utilized. after the reactions, the reactor was immersed in cold water to cool to room temperature, and the liquid phases were removed using filtering. 2.5. product analysis the amount of hmf and glucose in the reaction solutions was determined using high-performance liquid chromatography (hplc) as analytical method. a separation module lc-2030, a column ods (250 × 4.6) mm, and a detector type pda were used in the hplc study (photodiode array detector). the mobile phase for the shimadzu (3d) type of hplc was 80% methanol and 20% h2o; flow rate was 1 ml/min; volume was 20 µl; particle size was 5 µm). the uv detection for hmf was performed at 285 nm, with the column temperature kept constant at room temperature. the concentrations of substrate and product were obtained using a standard calibration curve, and the glucose conversion, hmf yield, and hmf selectivity were computed using the equations below: conversion (%) = 𝑚𝑜𝑙𝑒 𝑜𝑓 𝑠𝑡𝑎𝑟𝑡𝑖𝑛𝑔 𝑔𝑙𝑢𝑐𝑜𝑠𝑒 – 𝑚𝑜𝑙𝑒 𝑜𝑓 𝑔𝑙𝑢𝑐𝑜𝑠𝑒 𝑟𝑒𝑚𝑎𝑖𝑛𝑖𝑛𝑔 𝑚𝑜𝑙𝑒 𝑜𝑓 𝑠𝑡𝑎𝑟𝑡𝑖𝑛𝑔 𝑓𝑟𝑢𝑐𝑡𝑜𝑠𝑒 × 100 (1) hmf yield (%) = 𝑚𝑜𝑙𝑒𝑠 𝑜𝑓 𝐻𝑀𝐹 𝑝𝑟𝑜𝑑𝑢𝑐𝑒𝑑 𝑚𝑜𝑙𝑒 𝑜𝑓 𝑠𝑡𝑎𝑟𝑡𝑖𝑛𝑔 𝑔𝑙𝑢𝑐𝑜𝑠𝑒 × 100 (2) hmf selectivity (%) = 𝑚𝑜𝑙𝑒𝑠 𝑜𝑓 𝐻𝑀𝐹 𝑝𝑟𝑜𝑑𝑢𝑐𝑒𝑑 𝑚𝑜𝑙𝑒 𝑜𝑓 𝑠𝑡𝑎𝑟𝑡𝑖𝑛𝑔 𝑔𝑙𝑢𝑐𝑜𝑠𝑒 – 𝑚𝑜𝑙𝑒 𝑜𝑓 𝑔𝑙𝑢𝑐𝑜𝑠𝑒 𝑟𝑒𝑚𝑎𝑖𝑛𝑖𝑛𝑔 × 100 (3) 3results and discussion 3.1. catalyst characterization the results of bet analysis for graphite and sulfonated graphite are reported in table 1. an approximately large change was observed in the surface area of sulfonated graphite as compared to graphite. maximum pore volume (0.0449 cm 3 /g) was observed for sulfonated graphite as compared to graphite 0.0022 cm 3 /g showing an increase in the porous structure of the catalyst. hence, chemical modification has a significant role to increase the surface area of the catalyst. table 1. physical structure characterization of graphite and sulfonated graphite properties graphite sulfonated graphite total surface area (b.e.t) m 2 /g 0.579 79.972 total pore volume, cm 3 /g 0.0022 0.0449 a. s. al-nuaimi and m. j. ahmed / iraqi journal of chemical and petroleum engineering 23,1 (2022) 23 29 26 3.2. effects of operating parameters a. temperature effect on glucose dehydration the reaction temperature has a significant impact on the yield of 5-hmf formed from glucose using sulfonated graphite (sg) as a catalyst. as shown in fig. 3, when the reaction temperature was raised from 120 to 180 °c, the peak 5-hmf yield increased from 26.4% to 46.25%, while glucose conversion and selectivity increased (64.8– 87.5% and 40.74–52.85%, respectively), indicating that the higher temperature resulted in a faster peak value and higher hmf yield, when the temperature hit 200°c, the yield of hmf reduced by 43.84 %. mostly because of unexplained soluble polymers and humins that resulted from side reactions. fig. 3. the influence of temperature on glucose dehydration to 5-hmf in dmso over sg catalyst (mcata = 1g, time = 2 hr) b. time effect on glucose dehydration the results of the influence of time on the dehydration reaction of glucose are shown in fig. 4. the yield of hmf increased dramatically with increasing reaction time, rising from 23.3% to 51.76% when the reaction period was increased from 0.5 to 3 hours. the hmf yield was then reduced to 44.18% after a four-hour dip. as reported previously [10], the lower hmf production after 4 hr could be due to additional converting to by-products. as a result, the reaction using sulfonated graphite (sg) as a catalyst was chosen to be examined at 160°c for 3 hours. fig. 4. the influence of time on glucose dehydration to 5hmf in dmso over sg catalyst (mcata=1g, temperature = 160°c) c. catalyst loading effect on glucose dehydration the effect of varying catalyst amounts in the range of 0.25 to 2.5 g was investigated. the best yield of hmf (53.2%) was obtained with a catalyst loading of 2 g, according to the results given in fig. 5. the hmf yield fell when the amount of catalyst was increased; for example when the catalyst loading was 2.5 g, the hmf yield dropped to 51.8 %, likely because the system's high acidity was susceptible to the development of sidereactions. at 160°c for 2 hours, the effect of h2so4 loading on the dehydration of glucose to hmf with dmso as the solvent. due to the additional conversion of hmf to la, increasing the h2so4 level resulted in a drop in hmf production. fig. 5. the influence of catalyst loading on the glucose dehydration to 5-hmf in dmso over sg catalyst (time = 2hr, temperature = 160°c) d. optimum operating condition all of the experiments were studied, and the best operating parameters for dealing were established based on temperature, time, and catalyst loading. the best conditions for producing 5-hmf from glucose were found to be at 180°c for 3 hr, with a catalyst loading of 2g and dmso as the solvent. the glucose conversion rate was 97.5%, and the yield of hmf was 56.53%. for these conditions fig. 6 shows dehydration of glucose to 5hmf. fig. 6. the glucose dehydration to 5-hmf in dmso over sg catalyst (time = 3hr, temperature = 180°c, mcat = 2g) 4conclusions a. s. al-nuaimi and m. j. ahmed / iraqi journal of chemical and petroleum engineering 23,1 (2022) 23 29 27 this research proposes a more environment friendly and intensive approach for effective conversion of biomass into valuable products. both catalysts and solvents are required for the conversion of glucose to 5-hmf. the use of sulfonated graphite (sg) as a catalyst, which is generated from spent dry batteries, has been shown to be promising method, yielding a maximum of 56.53 % of 5hmf at 180°c for 3 hours with a catalyst loading of 2g and dmso as the solvent. the dmso solvent helps to increase product yield while also shortening reaction times. this technique of converting glucose to 5-hmf is environment friendly and energy efficient. references [1] christensen, c. h.; rass‐hansen, j.; marsden, c. c.; taarning, e.; egeblad, k. “ the renewable chemicals industry”. chemsuschem 2008, 1, 283-289. [2] normile, d., round and round: a guide to the carbon cycle. science 2009, 325, 16421643. [3] alaa k. m., safa a. al -rassul. and mohammed b., bio-production of ethanol in packed bioreactor, lraqi journal of chemical and petroleum engineering 2009, 10(4), 45-48 [4] zhou, c.-h.; xia, x.; lin, c.-x.; tong, d.-s.; beltramini, j. “ catalytic conversion of lignocellulosic biomass to fine chemicals and fuels”. chem. soc. rev. 2011, 40, 55885617. [5] hessel, v. “ catalytic process development for renewable materials”. green processing and synthesis 2013, 2, 375-376. [6] qiao, y., n. theyssen, and hou, z. “acid-catalyzed dehydration of fructose to 5(hydroxymethyl)furfural”. recyclable catalysis, 2015. 2(1). [7] zhang, m.f., qin,y.h., ma,j.y., yang, l., wu, z.k., wang, t.l., wang, w.g., wang, c.w. “depolymerization of microcrystalline cellulose by the combination of ultrasound and fenton reagent”, ultrason. sonochem. 31 (2016) 404–408. [8] bhaumik, p. and dhepe, p. l. “influence of properties of sapo's on the one-pot conversion of mono-, di and poly-saccharides into 5-hydroxymethylfurfural”. rsc advances, 2013. 3(38): p. 17156-17165. [9] wang, t.f., nolte, m.w., shanks, b.h. “catalytic dehydration of c-6 carbohydrates for the production of hydroxymethylfurfural (hmf) as a versatile platform chemical”, green chem. 16 (2014) 548–572. [10] neran k. i., shahrazad r. r., zainab a. n., “removal of so2 over modified activated carbon in fixed bed reactor: i, effect of metal oxide loadings and acid treatment”, lraqi journal of chemical and petroleum engineering, 2014, 15(4), 25-35. [11] tong, x.l., yu, l.h., nie,g.x., li, z.m., liu, j.b. xue, s. “antimony-meditated efficient conversion of carbohydrates to 5hydroxymethylfurfural in a simple thf-h2o binary solvent”, environ. prog. sustain. energy 34 (2015) 1136–1141. [12] li, m.h., li, w.z., lu, y.j., jameel, h., chang, h.m., ma, l.l. “high conversion of glucose to 5hydroxymethylfurfural using hydrochloric acid as a catalyst and sodium chloride as a promoter in a water/gamma-valerolactone system”, rsc adv. 7 (2017) 14330–14336. [13] karimi, b., mirzaei, h.m., behzadnia,h., vali, h. “novel ordered mesoporous carbon based sulfonic acid as an efficient catalyst in the selective dehydration of fructose into 5-hmf: the role of solvent and surface chemistry”, acs appl. mater. interfaces 7 (2015) 19050–19059. [14] ordomsky, v.v., van der schaaf, j., schouten, j.c., nijhuis, t.a. “fructose dehydration to 5hydroxymethylfurfural over solid acid catalysts in a biphasic system”, chemsuschem 5 (2012) 1812– 1819. [15] ennaert, t., van aelst, j., dijkmans, j., de clercq, r., schutyser, w., dusselier, m., verboekend, d., sels, b.f. “potential and challenges of zeolite chemistry in the catalytic conversion of biomass”, chem. soc. rev. 45 (2016) 584–611. [16] catrinck, m.n., ribeiro, e.s., monteiro, r.s., ribas, barbosa, r.m. m.h.p., teofilo, r.f. “direct conversion of glucose to 5-hydroxymethylfurfural using a mixture of niobic acid and niobium phosphate as a solid acid catalyst”, fuel 210 (2017) 67–74. [17] osatiashtiani, a., lee, a.f., granollers, m., brown, d.r., olivi, l., morales, g. j., melero, a., wilson, k. “hydrothermally stable, conformal, sulfated zirconia mono layer catalysts for glucose conversion to 5-hmf”, acs catal. 5 (2015) 4345– 4352. [18] yu,i.k.m., tsang, d.c.w. “conversion of biomass to hydroxymethylfurfural: a review of catalytic systems and underlying mechanisms”, bioresour. technol. 238 (2017) 716–732. [19] yang, l., tsilomelekis, g., caratzoulas, s., vlachos, d.g. “mechanism of brønsted acidcatalyzed glucose dehydration”, chemsuschem 8 (2015) 1334– 1341. [20] pedersen, a.t., ringborg, r., grotkjaer, t., pedersen, s., woodley, j.m. “synthesis of 5 hydroxymethylfurfural (hmf) by acid catalyzed dehydration of glucose-fructose mixtures”, chem. eng. j. 273 (2015) 455–464. [21] tsilomelekis, g., orella, m.j., lin, z.x., cheng, z.w., zheng, w.q. nikolakis, v., vlachos, d.g. “molecular structure, morphology and growth mechanisms and rates of 5-hydroxymethyl furfural (hmf) derived humins”, green chem. 18 (2016) 1983–1993. [22] ren, l.k., zhu, l.f., qi, t., tang, j.q., yang, h.q. hu, c.w. “performance of dimethyl sulfoxide and bronsted acid catalysts in fructose conversion to https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/cssc.200700168 https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/cssc.200700168 https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/cssc.200700168 https://www.science.org/doi/full/10.1126/science.325_1642 https://www.science.org/doi/full/10.1126/science.325_1642 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/420 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/420 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/420 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/420 https://pubs.rsc.org/en/content/articlelanding/2011/cs/c1cs15124j/unauth https://pubs.rsc.org/en/content/articlelanding/2011/cs/c1cs15124j/unauth https://pubs.rsc.org/en/content/articlelanding/2011/cs/c1cs15124j/unauth https://pubs.rsc.org/en/content/articlelanding/2011/cs/c1cs15124j/unauth https://www.degruyter.com/document/doi/10.1515/gps-2013-0057/html https://www.degruyter.com/document/doi/10.1515/gps-2013-0057/html https://www.degruyter.com/document/doi/10.1515/gps-2013-0057/html http://psjd.icm.edu.pl/psjd/element/bwmeta1.element.-psjd-doi-10_1515_recat-2015-0006;jsessionid=54eb9fdb297335f3018aa06e81b01650 http://psjd.icm.edu.pl/psjd/element/bwmeta1.element.-psjd-doi-10_1515_recat-2015-0006;jsessionid=54eb9fdb297335f3018aa06e81b01650 http://psjd.icm.edu.pl/psjd/element/bwmeta1.element.-psjd-doi-10_1515_recat-2015-0006;jsessionid=54eb9fdb297335f3018aa06e81b01650 http://psjd.icm.edu.pl/psjd/element/bwmeta1.element.-psjd-doi-10_1515_recat-2015-0006;jsessionid=54eb9fdb297335f3018aa06e81b01650 https://www.sciencedirect.com/science/article/abs/pii/s135041771630027x https://www.sciencedirect.com/science/article/abs/pii/s135041771630027x https://www.sciencedirect.com/science/article/abs/pii/s135041771630027x https://www.sciencedirect.com/science/article/abs/pii/s135041771630027x https://www.sciencedirect.com/science/article/abs/pii/s135041771630027x https://pubs.rsc.org/en/content/articlelanding/2013/ra/c3ra43197e/unauth https://pubs.rsc.org/en/content/articlelanding/2013/ra/c3ra43197e/unauth https://pubs.rsc.org/en/content/articlelanding/2013/ra/c3ra43197e/unauth https://pubs.rsc.org/en/content/articlelanding/2013/ra/c3ra43197e/unauth https://pubs.rsc.org/en/content/articlelanding/2014/gc/c3gc41365a/unauth https://pubs.rsc.org/en/content/articlelanding/2014/gc/c3gc41365a/unauth https://pubs.rsc.org/en/content/articlelanding/2014/gc/c3gc41365a/unauth https://pubs.rsc.org/en/content/articlelanding/2014/gc/c3gc41365a/unauth https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/295 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/295 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/295 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/295 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/295 https://aiche.onlinelibrary.wiley.com/doi/abs/10.1002/ep.12103 https://aiche.onlinelibrary.wiley.com/doi/abs/10.1002/ep.12103 https://aiche.onlinelibrary.wiley.com/doi/abs/10.1002/ep.12103 https://aiche.onlinelibrary.wiley.com/doi/abs/10.1002/ep.12103 https://aiche.onlinelibrary.wiley.com/doi/abs/10.1002/ep.12103 https://aiche.onlinelibrary.wiley.com/doi/abs/10.1002/ep.12103 https://pubs.rsc.org/en/content/articlehtml/2017/ra/c7ra00701a https://pubs.rsc.org/en/content/articlehtml/2017/ra/c7ra00701a https://pubs.rsc.org/en/content/articlehtml/2017/ra/c7ra00701a https://pubs.rsc.org/en/content/articlehtml/2017/ra/c7ra00701a https://pubs.rsc.org/en/content/articlehtml/2017/ra/c7ra00701a https://pubs.rsc.org/en/content/articlehtml/2017/ra/c7ra00701a https://pubs.acs.org/doi/abs/10.1021/acsami.5b03985 https://pubs.acs.org/doi/abs/10.1021/acsami.5b03985 https://pubs.acs.org/doi/abs/10.1021/acsami.5b03985 https://pubs.acs.org/doi/abs/10.1021/acsami.5b03985 https://pubs.acs.org/doi/abs/10.1021/acsami.5b03985 https://pubs.acs.org/doi/abs/10.1021/acsami.5b03985 https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/cssc.201200072 https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/cssc.201200072 https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/cssc.201200072 https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/cssc.201200072 https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/cssc.201200072 https://pubs.rsc.org/en/content/articlehtml/2016/cs/c5cs00859j https://pubs.rsc.org/en/content/articlehtml/2016/cs/c5cs00859j https://pubs.rsc.org/en/content/articlehtml/2016/cs/c5cs00859j https://pubs.rsc.org/en/content/articlehtml/2016/cs/c5cs00859j https://pubs.rsc.org/en/content/articlehtml/2016/cs/c5cs00859j https://www.sciencedirect.com/science/article/abs/pii/s0016236117310207 https://www.sciencedirect.com/science/article/abs/pii/s0016236117310207 https://www.sciencedirect.com/science/article/abs/pii/s0016236117310207 https://www.sciencedirect.com/science/article/abs/pii/s0016236117310207 https://www.sciencedirect.com/science/article/abs/pii/s0016236117310207 https://pubs.acs.org/doi/abs/10.1021/acscatal.5b00965 https://pubs.acs.org/doi/abs/10.1021/acscatal.5b00965 https://pubs.acs.org/doi/abs/10.1021/acscatal.5b00965 https://pubs.acs.org/doi/abs/10.1021/acscatal.5b00965 https://pubs.acs.org/doi/abs/10.1021/acscatal.5b00965 https://pubs.acs.org/doi/abs/10.1021/acscatal.5b00965 https://www.sciencedirect.com/science/article/abs/pii/s0960852417305072 https://www.sciencedirect.com/science/article/abs/pii/s0960852417305072 https://www.sciencedirect.com/science/article/abs/pii/s0960852417305072 https://www.sciencedirect.com/science/article/abs/pii/s0960852417305072 https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/cssc.201403264 https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/cssc.201403264 https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/cssc.201403264 https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/cssc.201403264 https://www.sciencedirect.com/science/article/abs/pii/s1385894715004106 https://www.sciencedirect.com/science/article/abs/pii/s1385894715004106 https://www.sciencedirect.com/science/article/abs/pii/s1385894715004106 https://www.sciencedirect.com/science/article/abs/pii/s1385894715004106 https://www.sciencedirect.com/science/article/abs/pii/s1385894715004106 https://pubs.rsc.org/en/content/articlehtml/2016/gc/c5gc01938a https://pubs.rsc.org/en/content/articlehtml/2016/gc/c5gc01938a https://pubs.rsc.org/en/content/articlehtml/2016/gc/c5gc01938a https://pubs.rsc.org/en/content/articlehtml/2016/gc/c5gc01938a https://pubs.rsc.org/en/content/articlehtml/2016/gc/c5gc01938a https://pubs.rsc.org/en/content/articlehtml/2016/gc/c5gc01938a https://pubs.acs.org/doi/abs/10.1021/acscatal.6b01802 https://pubs.acs.org/doi/abs/10.1021/acscatal.6b01802 https://pubs.acs.org/doi/abs/10.1021/acscatal.6b01802 a. s. al-nuaimi and m. j. ahmed / iraqi journal of chemical and petroleum engineering 23,1 (2022) 23 29 28 5-hydroxymethylfurfural”, acs catal. 7 (2017) 2199– 2212. [23] aida, t.m., sato, y., watanabe, m., tajima, k., nonaka,t., hattori, h., arai, k. “dehydration of dglucose in high temperature water at pressures up to 80 mpa”, j. supercrit. fluids 40 (2007) 381–388. [24] mirzaei, h.m., karimi, b. “sulphanilic acid as a recyclable bifunctional organocatalyst in the selective conversion of lignocellulosic biomass to 5-hmf”, green chem. 18 (2016) 2282–2286. [25] stahlberg, t., fu, w.j., woodley, j.m., riisager,a. “synthesis of 5-(hydroxymethyl) furfural in ionic liquids: paving the way to renewable chemicals”, chemsuschem 4 (2011) 451–458. [26] alonso, d.m., wettstein, s.g., dumesic, j.a. “gamma-valerolactone, a sustainable platform molecule derived from lignocellulosic biomass”, green chem. 15 (2013) 584–595. [27] feng,y., qu,j., zhang,q., cong, q., luo, c.q., yuan,x. “a new insight of recycling of spent zn–mn alkaline batteries: synthesis of znxmn1−xo nanoparticles and solar light driven photocatalytic degradation of bisphenol a using them”, j. alloys compd. 622 (2015) 703–707. [28] han, d.m., nan, j.m., 2005. “advances on the recycling and reusing of spent batteries”, chin. j. power sources 29, 128–131. [29] olivetti, e.; jeremy g.; randolph k. (february 2011). "life cycle impacts of alkaline batteries with a focus on end-of-life ebpa-eu" (pdf). massachusetts institute of technology, materials systems lab. p. 110. archived from the original (pdf) on 2011-10-07. retrieved 29 july 2014. [30] absatzzahlen 2008 (pdf) (in german). interessenorganisation batterieentsorgung. archived from the original (pdf) on march 25, 2012. retrieved 29 july 2014. [31] fisher, k.; wallén, e.; laenen, p. p.; collins, m., "battery waste management life cycle assessment." environmental resources management erm, ltd (2006). . https://pubs.acs.org/doi/abs/10.1021/acscatal.6b01802 https://pubs.acs.org/doi/abs/10.1021/acscatal.6b01802 https://www.sciencedirect.com/science/article/abs/pii/s0896844606002117 https://www.sciencedirect.com/science/article/abs/pii/s0896844606002117 https://www.sciencedirect.com/science/article/abs/pii/s0896844606002117 https://www.sciencedirect.com/science/article/abs/pii/s0896844606002117 https://pubs.rsc.org/en/content/articlelanding/2016/gc/c5gc02440d/unauth https://pubs.rsc.org/en/content/articlelanding/2016/gc/c5gc02440d/unauth https://pubs.rsc.org/en/content/articlelanding/2016/gc/c5gc02440d/unauth https://pubs.rsc.org/en/content/articlelanding/2016/gc/c5gc02440d/unauth https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/cssc.201000374 https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/cssc.201000374 https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/cssc.201000374 https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/cssc.201000374 https://pubs.rsc.org/en/content/articlelanding/2013/gc/c3gc37065h/unauth https://pubs.rsc.org/en/content/articlelanding/2013/gc/c3gc37065h/unauth https://pubs.rsc.org/en/content/articlelanding/2013/gc/c3gc37065h/unauth https://pubs.rsc.org/en/content/articlelanding/2013/gc/c3gc37065h/unauth https://www.sciencedirect.com/science/article/abs/pii/s0925838814026048 https://www.sciencedirect.com/science/article/abs/pii/s0925838814026048 https://www.sciencedirect.com/science/article/abs/pii/s0925838814026048 https://www.sciencedirect.com/science/article/abs/pii/s0925838814026048 https://www.sciencedirect.com/science/article/abs/pii/s0925838814026048 https://www.sciencedirect.com/science/article/abs/pii/s0925838814026048 https://www.epbaeurope.net/assets/resources/nema_alkalinelca2011.pdf https://www.epbaeurope.net/assets/resources/nema_alkalinelca2011.pdf https://www.epbaeurope.net/assets/resources/nema_alkalinelca2011.pdf https://www.epbaeurope.net/assets/resources/nema_alkalinelca2011.pdf https://www.epbaeurope.net/assets/resources/nema_alkalinelca2011.pdf https://www.epbaeurope.net/assets/resources/nema_alkalinelca2011.pdf http://www.lcm2007.ethz.ch/paper/424.pdf http://www.lcm2007.ethz.ch/paper/424.pdf http://www.lcm2007.ethz.ch/paper/424.pdf http://www.lcm2007.ethz.ch/paper/424.pdf a. s. al-nuaimi and m. j. ahmed / iraqi journal of chemical and petroleum engineering 23,1 (2022) 23 29 29 فوق البطاريات الجافة فيرفرال هيدروكسي ميثيل -5التحويل التحفيزي للجلوكوز إلى المستعملة كعامل مساعد امنة سامي النعيمي، مثنى جبار احمد العراق-قسم الهندسة الكيمياوية/ جامعة بغداد/ بغداد الخالصة تعتبر الكتلة الحيوية مصدًرا شائًعا للكربون المتجدد ألنها تتمتع بإمكانيات كبيرة كبديل للوقود األحفوري (. تمت دراسة hmf)فيرفرال هيدروكسي ميثيل -5الشحيح ، وقد تم استخدامها لصنع مركبات أساسية مثل . تم بذل hmfالجلوكوز ، وهو أحد المكونات الرئيسية للكتلة الحيوية ، على نطاق واسع باعتباره مقدمة إلنتاج ، وهي منصة كيميائية تستخدم في تصنيع hmfالعديد من الجهود إليجاد إجراءات فعالة وقابلة للتكرار لتركيب ( من البطاريات الجافة المستهلكة sgالمسلفن )الكرافيت تصنيع الوقود والمركبات األخرى عالية القيمة. تم رجة الحرارة (. كانت دhmf)فيرفرال هيدروكسي ميثيل -5لتحويل الجلوكوز إلى كعامل مساعد واستخدامه من بين المتغيرات التي تمت دراستها. عندما تم استخدام ثنائي ميثيل العامل المساعد ووقت التفاعل وتحميل وتحويل hmfساعات من وقت التفاعل ، تم تحقيق أكبر ناتج 3درجة مئوية بعد 180د كمذيب عند سلفوكسي ٪ على التوالي. توضح هذه الدراسة كيفية تصنيع 57.979٪ و 97.5٪ و 56.53الجلوكوز واالنتقائية بنسبة ئية أساسية قائمة على أساس لتحويل الجلوكوز إلى مواد كيميانشاط العامل المساعد الجرافيت المسلفن مع زيادة حيوي بطريقة مستدامة طويلة األجل. .( ، تحويل الجلوكوزhmf)فيرفرال هيدروكسي ميثيل-5الكتلة الحيوية ، الكلمات الدالة: iraqi journal of chemical and petroleum engineering vol.18 no.4 (december 2017) 1 13 issn: 1997-4884 study the effect of using microwave radiation and h-donors on improving heavy oil hussein qasim hussein and zeina abbas khedheer chemical engineering department, college of engineering, university of baghdad abstract the present research has investigated the effect of microwave energy on improving the flow properties of heavy crude oil. the fragmentation of crude oil molecules was carried out with and without using 1 and 10 wt. % concentration of various types of h-donors like tetralin, cyclohexane, and naphtha. microwave power of 320, 385, and 540 w and radiation time 1-9 min, and temperature were studied. the kinematic viscosity and asphaltene content were measured for evaluation the improving of heavy crude oil. results show that viscosity of crude oil decreased with increase h-donor concentration, a maximum percentage of viscosity reduction was10.63 % for tetralin at 6 min radiation time, while 8.67%, and 7.34% for cyclohexane and naphtha at 4 min respectively. the high h-donor polarity is the high viscosity reduction. the asphaltenes content of crude oil was decreased during microwave treatment process, a maximum percentage of reduction was 39.73% for tetralin at 6 min radiation time, while 34.40% and 46.29 % for cyclohexane and naphtha at 4 min respectively. the viscosity of crude oil was decreased with asphaltenes content decrease. the temperature of a crude oil was varied during the microwave treatment and it was depended on radiation time and radiation power and h-donor type. the best reduction of crude oil viscosity and asphaltenes content was achieved at a moderate radiation power385 w. key words: microwave heating, heavy crude oil, h-donors. introduction the continuous depletion of conventional light crude oil led to increasing interest in the upgrading of heavy crude oil and residue, which considered a huge resource of energy [1, 2]. on the other hand, heavy oils and bitumens contain a number of high molecular weight components and an aggregate that was require more processing steps in order to be converted into useful finished products. the characterization of these components is high viscosity values, high asphaltenes content, high metals (e.g., ni, v, and fe), high hetroatom (e.g., s, n, and o) and low api gravity [3]. university of baghdad college of engineering iraqi journal of chemical and petroleum engineering study the effect of using microwave radiation and h-donors on improving heavy oil 2 ijcpe vol.18 no.4 (dec. 2017) -available online at: www.iasj.net the us department of energy classified: heavy oil as whose api gravity between 10° and 20°. bitumen and extra heavy oil with api less than 10° [4, 5] , which make them difficult to process compared with light crude oil , and that cause challenges for upgrading such oil. these challenges impact producing, transporting and refining heavy oil [6, 2]. heavy crude oil can be upgrade to lighter oil using several techniques. however, current methods (conventional) usually require high temperature, long reaction duration, high costs, and cause serious environmental pollution, with and without using catalysts. these techniques include thermal processes, hydroprocesses, separation processes etc. therefore, many new technologies (unconventional) used for upgrading heavy oil involve the use of electric field, ultrasonic energy, magnetic field, and biological processing [7, 8, 9]. the technology used is microwave energy, and is represents an alternative to the conventional methods which it has many benefits. these benefits include are fast, clean eco-friendly, economic and selective heating [10, 11]. this technique based on electromagnetic waves which that pass through the material cause its molecules to oscillate, molecules try to orient themselves with the field and generating heat [11]. however, materials exposure to electromagnetic waves dependent on dielectric properties that interact strongly with polar materials and weakly with others [12, 13]. it is preferred to use h-donor in the upgrading process assisted by microwave oven because of the hydrogen formed from dehydrogenation of hydrogen donors helps to stabilize generated free radical that are formed during cracking reaction, to narrow the molecular weight distribution of the product [14, 3]. several researches worked on sharky baghdad heavy crude oil to upgrading as hussain et al., 2011[15], used distillation and solvent extraction to get the deasphaltened oil (dao), they were observed that api of dao increased twice the api of reduced crude oil while sulfur and metals content decreased 20% and 50% respectively. mohammed, 2013[6], used different types of hydrocarbon and oxygenated polar solvents such as toluene, methanol, mix xylenes, and reformate, and different types of dispersants to reduce its viscosity from break down asphaltene agglomerates, results show that the high solvent polarity is high viscosity reduction and high asphaltenes content reduction. also, many attempts used microwave heating with and absence h-donors in crude oil treatment such as, britten et al., 2005[12], used heavy petroleum samples with or without hydrogen donor addition using microwave energy process. they were observed with longer radiation time asphaltenes increased due to recombination reaction which is associated with high temperature. the maximum reduction percentage of asphaltenes content was 18.60% for kerrbert heavy crude oil, while the reduction percentage of asphaltenes content was 28.57% when using 55wt. % naphtha at the same radiation time 2 min. miadonye a. & macdonald b., 2014[10], studied the performance of microwave irradiation for upgrading heavy crude oil and bitumen by inducing petroleum visbreaking, and used di-ethanolamine dea as hydrogen donor with different sensitizer (activated charcoal, serpentine). hussein qasim hussein and zeina abbas khedheer -available online at: www.iasj.net ijcpe vol.18 no.4 (dec. 2017) 3 the results indicate that the reductions of viscosity crude oil at the same radiation time were 73.10% for 10 wt. % dea with crude oil and 77.93 wt. % for 10 wt. % dea and activated charcoal with crude oil. mohammed et al., 2011[16], used microwave oven and atmospheric distillation to upgrading heavy petroleum without any addition of chemicals or additives, and studied different of power and exposure time for irradiation microwave and from distillation results show that low power rates was very effective and gave a higher products yield due to fragmentation reaction. the objective of present research is improving properties of iraqi heavy oil by hydrogen donor assisted by microwave heating. this technology is based on the reduction of viscosity and asphaltenes content of heavy oil due to maximum break-up in asphaltene molecules. the upgrading of heavy oil by microwave is come out at different conditions as follows: crude oil (without addition), different types of hydrogen donors (tetralin, cyclohexane, light naphtha), and concentration (1 and 10 wt. %), and studying the influence of different power level, radiation period, and reaction temperature. experimental work materials 1the feed stock of heavy crude oil in this study was supplied from east baghdad oil fields, well number 14, with physical properties in table 1. table 1, physical properties of iraqi heavy crude oil test value kinematic viscosity (cst.) 163 api at 60 f° 18.5 density at 15 c° 0.9428 asphaltenes content wt.% 7.27 sulfur content wt.% 4.81 2hydrogen donors used for treatment crude oil in this study were: a. tetralin with 0.97 specific gravity and (206-208) °c boiling point supplied by kunshan yolong trading company (china). b. cyclohexane with 0.78 specific gravity and 81°c boiling point supplied by ridel-dehaen agseelze company (germany). c. light naphtha, with 0.77 specific gravity and (30-90) °c boiling point supplied from al-doura refinery. microwave treatment unit for crude oil 1microwave set up this consists from the followings: microwave oven supplied by china with (mm717cpj) model, and power range (17l 700) watt. thermocouple with (m4012) model manufactured by (bbc-universal) germany guard read temperature from (-30 – 700) °c. q.v.f crucible tube with 2.5 inch diameter and 14 cm length. teflon tube, rubber stopper, teflon stopper, thermal isolator shield, dielectromagnetic flange as shown in figure1. fig.1, microwave treatment unit for crude oil study the effect of using microwave radiation and h-donors on improving heavy oil 4 ijcpe vol.18 no.4 (dec. 2017) -available online at: www.iasj.net 2microwave treatment procedure in case without addition: 40 gram of crude oil was used directed to run. in other hand, in case adding of h-donor was 40 gram crude oil and h-donor (1&10 wt. % base of crude oil) mixed using mechanical mixer for 10 min and 400 rpm. then, the prepared feed was put in q.v.f crucible tube. rubber stopper used to prevent escape of hydrocarbon vapor during microwave heating, and subsequently losses of the lighter molecules could be reduced. then, the sample was placed at the center of the microwave oven, then the microwave was switched on a certain power level (320, 385, and 540 watts), the radiation time for heating sample at different radiation period (19 min), the reaction temperature of sample was measured through thermocouple. then the sample was removed from microwave oven and it was left to cool to ambient temperature in sealed container for 1 day to allow all volatiles to condense and reconstitute a liquid phase. test of feed stock and products 1kinematic viscosity the kinematic viscosity of crude oil was measured by astm d 446 at 40 °c using canon-fenske, routine viscometer, (300 and 350) size number. 2asphaltenes content wt. % asphaltenes content of crude oil samples were measured as following procedure: taken 1 gram of crude oil. then, 30 ml of n-heptane was added to crude oil in a 250 ml conical flask and mixed well using magnetic stirrer with 500 rpm for 15 min at ambient temperature. then, the flask was covered and left for 48 hr. the mixture was then filtered using vacuum filtration unit and medium size of filter paper (no. 105). the precipitate asphaltene on filter paper was washed (2-4) times with 20 ml of n-heptane each time and filtration was continued at steady rate until washing are colorless. then, the precipitate (asphaltene) was dried in an oven over night at 100 °c. finally, the asphaltenes weighted to find the asphaltene content. results and discussions effect of microwave radiation time on properties of crude oil 1kinematic viscosity figure 2 shows comparison of kinematic viscosity of crude oil between heavy crude oil with and without using different types of hdonors at 10 wt. % concentration at 385 w. it is obvious that the kinematic viscosity response is unstable with radiation time, and there is a transference behavior. the viscosity heavy crude oil of thermally microwave was increased at radiation time from 1 to 2 min in spite of molecules fragmentation is occurred, due to the generation of light hydrocarbon molecules less than c5 at short radiation time [12], which could not retain in crude oil. then, viscosity began decreasing at 3 min radiation time and continued until 4 min. the percentages of viscosity reduction were 1.22% and 2.45% at time 3 and 4 min respectively. this decreasing in viscosity was due to the fragmentation of high molecular weight hydrocarbon molecules and especially the asphaltenes to a condensable hydrocarbon (c5-c20) [12]. then, the viscosity increased dramatically with increasing of radiation time from 5 to 9 min, due to increase of temperature led to the initiation of recombination reaction for fragmented molecules [13]. hussein qasim hussein and zeina abbas khedheer -available online at: www.iasj.net ijcpe vol.18 no.4 (dec. 2017) 5 while, it is clear that the viscosity change behavior affected by radiation time is relevant to the type of h-donor. in general, the kinematic viscosity at 1 min radiation time was increased for all types of h-donors. then, viscosity began to decrease until 3min radiation time where zero-time viscosity was approximately reached. beyond, a sharp decline in the viscosity was observed, and the maximum viscosity reduction was obtained 8.67% and 7.34% for cyclohexane and light naphtha respectively at 4min radiation time, but except the tetralin, where the maximum viscosity reduction 10.63% was obtained at 6min radiation time. the results indicated that tetralin gave the higher percentage of viscosity reduction compared with cyclohexane and light naphtha, and this occurred due to the disparity in the solvents polarity (tetralin ˃ cyclohexane ˃ light naphtha). also, tetralin give a better microwave absorption characteristic for the crude oil at low temperature, and this in agreement with miadonye, 2014 [10]. after that time, the kinematic viscosity increased gradually with radiation time due to increase of temperature led to the initiation of recombination reaction for fragmented molecules [13]. fig. 2, effect of radiation time on kinematic viscosity of crude oil with and without various types of h-donors addition at 10 wt. % concentration and 385w figure 3 shows comparison of kinematic viscosity of crude oil between heavy crude oil with and without using different types of hdonors at 1 wt. % concentration. it could be recognized that viscosity increased during first two minutes radiation time. it is worth mentioning that the viscosity response was approximately similar for all h-donors and crude oil without addition at 1wt. %, while a diverse in behavior between the h-donors types and crude oil without addition was clear at 10wt. %. after that, the viscosity decreased until maximum reduction 3.58% and 2.70% for cyclohexane and light naphtha was achieved respectively at 4min radiation time. on other hand, the maximum viscosity reduction 3.44% for tetralin was achieved at 6min radiation time. cyclohexane gave the maximum viscosity reduction at 1wt. % among the other h-donors, and this situation agree well to the explanation by hart, 2015 [3] dehydrogenation of cyclohexane (ch) could liberate hydrogen for hydrocracking and hydrogenation reactions, if the partial pressure of hydrogen is high enough. after that time, viscosity increased gradually with increasing radiation time, and this back to recombination reaction. study the effect of using microwave radiation and h-donors on improving heavy oil 6 ijcpe vol.18 no.4 (dec. 2017) -available online at: www.iasj.net fig. 3, effect of radiation time on kinematic viscosity of crude oil with and without various types of h-donors addition at 1 wt. % concentration and 385w for comparison between figures 2 and 3, observed that the viscosity for 10wt. % h-donors gave higher percentages of reduction and response a diverse in behavior between the hdonors types different than 1wt. % in viscosity and this reasons beyond to the presence h-donors material and ability of hydrogen atoms transferring to the heavy hydrocarbon in the oil led to restrict and minimizing the polymerization of the molecules (heavy oil) via free radicals, and improving quality of the crude oil [17, 10]. also, observed that the same behavior of effected radiation time on kinematic viscosity of crude oil ,where decreasing of kinematic viscosity due to the presence of light fractions at shorter radiation time and the strong possibility of the abundance of higher molecular weight hydrogen carbon due to increase the temperature at prolonged radiation time. figure 4 shows comparison of viscosity reduction percentage between crude oil without addition and hdonors types' addition, at 10wt. % and 1wt. % concentrations. at high concentration 10wt. %, observed that the maximum kinematic viscosity reduction percentage for tetralin at 6 min, while both cyclohexane and light naphtha at 4min, and this situation agree well to the explanation by vazquez, 2012 [17] described the importance of tetralin as hydrogen donor due to highly activated hydrogen atoms in the saturated ring adjacent to the aromatic ring. (a) (b) fig. 4, comparison between kinematic viscosity reduction percentages with and without various types of h-donors addition: (a) at 10 wt. concentration, and (b) at 1wt. % concentration hussein qasim hussein and zeina abbas khedheer -available online at: www.iasj.net ijcpe vol.18 no.4 (dec. 2017) 7 while, at low concentration 1wt. %, it is obvious that the kinematic viscosity reduction was convergent in values between tetralin and cyclohexane at different radiation time 6min and 4min respectively, but light naphtha gave lower reduction percent in kinematic viscosity, and this occurred due to the disparity in the solvents polarity (tetralin ˃ cyclohexane ˃ light naphtha). also, observed that the percentage of viscosity reduction of crude oil without addition is 2.45% at 4min lower than when using h-donors. 2asphaltene content figures 5 and 6 show the effect of radiation time on asphaltene content of crude oil at 385w with and without using different h-donors type at 10 wt. % and 1wt. % concentration respectively. figure 5 shows the comparison of asphaltenes content of heavy crude oil between heavy crude oil without addition and using different types of h-donors at 10 wt. % concentration. the asphaltenes content has diverse respond with radiation time during microwave treatment. where, asphaltenes content increased slightly from start to 1 min radiation time, caused by losing the light hydrocarbons (less than c5) produced by fragmentation which occur at short radiation time and led to concentrate the high molecular weight hydrocarbons (asphaltenes). beyond the 1 min radiation time, the asphaltenes content began to decline until 4 min where a maximum percentage of asphaltenes reduction 8.243% is achieved. while, the maximum percentage of asphaltene content reduction was 34.30% and 46.29% for cyclohexane and light naphtha respectively at 4 min radiation time, while 39.73% for tetralin at 6 min. this sharp decline is an evidence of asphaltenes molecules fragmentation to condensable distillates [12]. after that, the asphaltene content of heavy crude oil was increased due to increase of temperature at longer radiation period lead to recombination reaction [12]. fig. 5, effect of radiation time on asphaltene content of crude oil with and without various types of h-donors addition at 10 wt. % concentration and 385w figure 6 shows the comparison of asphaltenes content of heavy crude oil between heavy crude oil without addition and using different types of h-donors at 1 wt. % concentration. the asphaltene content at 1 and 2 min radiation time was increased slightly and convergent curves for all types of h-donors addition. then, the maximum percentages of asphaltene content reduction at the same radiation time when 10 wt. % were: 23.96% for tetralin, and 21.94% for cyclohexane, while 19.83% for light naphtha. after that, the asphaltene content of heavy crude oil was increased with increasing radiation time, back to recombination reaction [12]. study the effect of using microwave radiation and h-donors on improving heavy oil 8 ijcpe vol.18 no.4 (dec. 2017) -available online at: www.iasj.net fig. 6, effect of radiation time on asphaltene content of crude oil with and without various types of h-donors addition at 1 wt. % concentration and 385w figure 7 shows comparison of asphaltene content percentage between crude oil without addition and hdonors types' addition, at 10 wt. % and 1wt. % concentrations. the asphaltenes content reduction of crude oil without addition is lower than when using different h-donors addition due to hydrogen transfer from solvent to the heavy hydrocarbons in oil [3]. the asphaltenes content reduction increase with increasing h-donor concentration in their reaction mixture. this situation agrees well to the explanation by mohammed, 2012 [18] who reported for different concentration of h-donor with different type in reaction mixture. at 10 wt. % of h-donor, observed that light naphtha gave the higher reduction in asphaltene content compared with tetralin and cyclohexane, due to low aromaticity of solvent and temperature effects leading to micellation, agglomeration and precipitation of heavy molecules as asphaltenes, then these molecules step down of q.v.f crucible tube, and when exposure to microwave radiation leading to possible breakup or reorientation of asphaltene molecules [12]. but, at 1 wt. % of h-donor observed that tetralin give the higher reduction in asphaltene content from both light naphtha and cyclohexane. (a) (b) fig. 7, comparison between asphaltene content reduction percentages with and without various types of h-donors addition: (a) at 10 wt. concentration, and (b) at 1wt. % concentration 3the temperature profile figures 8 and 9 show the effect of radiation time on the temperature measured during the microwave heating of crude oil at 385w with and without using for different h-donors type at 10 wt. % and 1wt. % concentration respectively. it is clear that the temperature measured is proportional to radiation time, and increased gradually with hussein qasim hussein and zeina abbas khedheer -available online at: www.iasj.net ijcpe vol.18 no.4 (dec. 2017) 9 increasing of radiation time based on types of addition. also, it is clear that the temperature measured of crude oil without addition is lower than when using for different h-donors type at both concentration due to the poor microwave absorption characteristics of heavy crude oil which distinguished by several of researcher as [13, 14], and the measured temperature at 1 min radiation time was 35°c, and then continued increase until reached the 72°c at 9min. the results of measured temperature against microwave radiation time agreed with results of section 1.1 and 1.2 of microwave treatment, the reaction of cracking is strong dependent on the radiation time and observed that only heavy oil given the lower temperature, lower viscosity reduction percent, and the viscosity proportional to asphaltenes content due to the lower degree of fragmentation and hydrogenation saturation of the fragments to produce lower boiling fractions [10, 20]. figure 8 shows the effect of radiation time on temperature measured at 10 wt. % concentration of hdonors, at the beginning of microwave radiation, all hdonors had nearly values of temperature. but it rose very rapidly to around 60 °c in just 4 min, and then within the radiation time from 5 min to 7 min each type had taken different trend. thus, the curve of the 10 wt. % light naphtha and 10wt. % cyclohexane have had almost similar trends in such a way that their gradual temperature increase as function of radiation time had almost similar numerical values, within this period (4-7 min). then, the temperature increased with range from around 80 to more or less 90 °c for within 7 and 8 min respectively. fig. 8, effect of radiation time on temperature of crude oil with and without various h-donors addition types of h-donors addition at 10 wt. % concentration at 385 w radiation power figure 9 shows the effect of radiation time on temperature measured at 1 wt. % concentration of hdonors, at 1 min radiation time all hdonors had nearly values of temperature around 36 °c. it rose at radiation time between 1min to 6min where each type had taken different trend. then, temperatures were 83, 82, and 79 for tetralin, cyclohexane, and light naphtha to achieve a maximum at 9 min. as mentioned in the scope of these results indicated that increasing concentration led to increasing temperature , and specially 10 wt. % tetralin lead to increase degree of temperature due to polar nature of solvent that make it good absorption characteristics to microwave radiation[10]. these results for temperature agree with results of section 1 and 1 where increased the degree of fragmentation and hydrogenation saturation of the fragments to produce lowers boiling fractions increased when using hdonors. study the effect of using microwave radiation and h-donors on improving heavy oil 10 ijcpe vol.18 no.4 (dec. 2017) -available online at: www.iasj.net fig. 9, effect of radiation time on temperature of crude oil with and without various h-donors addition types of h-donors addition at 1 wt. % concentration at 385 w radiation power effect of microwave radiation power on properties of crude oil figures 10 and 11 shows the effect of radiation power on kinematic viscosity and asphaltenes content respectively with and without using 10 wt. % concentrations of h-donors and different radiation time according to the best result in section 1. figure 10 shows the effect of radiation power on the kinematic viscosity of crude oil with and without using 10wt. % of h-donors. it is obvious that the kinematic viscosity has diverse respond with the variation in radiation power. the change in the microwave power at the same of radiation time led to change in temperature, degree of fragmentation, and recombination, and subsequently the variation in crude oil characteristics. the percentage reduction of kinematic viscosity heavy crude oil without addition at 320 w and 385 w radiations power was increased from 1.226% to 2.453% respectively. the percentages of viscosity reduction of crude oil for tetralin, cyclohexane, and light naphtha were 5.57%, 5.02%, and 3.95% respectively at 320 w radiation power. while, at 385 w were 10.63%, 8.675%, and 6.21% for tetralin, cyclohexane, and light naphtha respectively. but, the kinematic viscosity of crude oil increased at 540 w radiation powers due to recombination is the predominant at high microwave power capacities. thus, the optimum heating in microwave were at low power rates due to fragment of higher molecular weight and formation of free radicals, which seem to recombined at zero energy activation, producing smaller normal and branched carbon chains ,this is similar to results obtained by mohammed,2011 and mohammed,2012[16, 18]. also, observed that 385 w radiation power giving higher reduction in kinematic viscosity than 320 w, also from figure 10 observed that tetralin gave higher reduction in kinematic viscosity than both cyclohexane, and light naphtha. fig. 10, effect of radiation power on kinematic viscosity of crude oil with and without 10wt. % h-donors hussein qasim hussein and zeina abbas khedheer -available online at: www.iasj.net ijcpe vol.18 no.4 (dec. 2017) 11 figure 11 shows the effect of radiation power on asphaltene content of heavy crude oil with and without using 10wt. % of h-donors. it is obvious that asphaltene content increased at 540w and decreased at both 320wand 385w radiation powers. thus, the percentage of asphaltenes content reduction of heavy crude oil without addition was 4.729% and 8.243% at 320w and 385w radiation power respectively. but, the percentages of asphaltene content reduction of heavy crude oil with using 10wt. % of h-donors at 320w were 20.36%, 25.87%, and 26.14% for tetralin, cyclohexane, and light naphtha respectively. at 385w, it mentioned earlier were 39.37%, 34.30%, and46.29% for tetralin, cyclohexane, and light naphtha respectively. at these powers, the asphaltenes content was reduced affected by fragmentation reaction due to the action of polar molecules and temperature caused permanent changes in petroleum reheology [19]. but, asphaltenes content increased at higher radiation power 540w. hence, increasing of asphaltenes content is due to the circumstances of the microwave associated with high radiation power which encourage the recombination reactions, of light hydrocarbon molecules [9]. fig. 11, effect of radiation power on asphaltene content of crude oil with and without 10wt. % h-donor conclusion in general, the effect of radiation power, radiation time, and type of addition with concentration promotes two reactions (fragmentation and recombination) during upgrading heavy crude oil. crude oil viscosity was decreasing with increasing polar solvent concentration except light naphtha represented special case could arguably be attributed to either poor solvent system or a combination of solvent and temperature effects. it was observed that the maximum viscosity reduction at 10 wt. % of hdonors was obtained 8.67% and 7.34% for cyclohexane and light naphtha respectively at 4min radiation time, but 10.63% for tetralin at 6min. while the maximum percentage of asphaltene content reduction was 34.30% and 46.29% for cyclohexane and light naphtha respectively at 4 min, while 39.73% for tetralin at 6 min. study the effect of using microwave radiation and h-donors on improving heavy oil 12 ijcpe vol.18 no.4 (dec. 2017) -available online at: www.iasj.net references 1santos, r.g., loh, w. & et al., 2014. an overview of heavy oil properties and its recovery and transportation methods. brazilian journal of chemical engineering vol., 31(3), pp.571–590. available at: www.abeq.org.br/bjche. 2zhang, z., 2011. experimental study of in-situ upgrading for heavy oil using hydrogen donors and catalyst under steam injection conditions. texas a&m university. 3hart, a., lewis, c. & et al., 2015. effect of cyclohexane as hydrogendonor in ultradispersed catalytic upgrading of heavy oil. fuel processing technology, 138, pp.724–733. available at: http://dx.doi.org/10.1016/j.fuproc.2 015.07.016. 4bjornseth, f., 2013. heavy oil production technology challenges and the effect of nano sized metals on the viscosity of heavy oil. thesis, norwegian university of science and technology. 5clark, b., 2007. heavy oil, extraheavy oil and bitumen unconventional oil. npc global oil and gas study, c(july 18 2007), pp.1–56. available at: http://www.npc.org/. 6mohammed, s. ,2013. viscosity reduction of sharqi baghdad heavy crude oil using different polar hydrocarbons, oxygenated solvents and dispersants. thesis, baghdad university. 7hmood, g.r., 2011. upgrading of basrah-kirkuk blend crude oil using mechanical-acoustical effect. thesis, university of technology. 8gupta, r.k. & gera, p., 2015. process for the up gradation of petroleum residue : review, report, india. 9lin, l., hong, l. & al., e., 2010. progress in the technology for desulfurization of crude oil. china petroleum processing and petrochemical technology, 12(2010, no. 4), pp.1–6. 10miadonye, a. & macdonald, b., 2014. microwave radiation induced visbreaking of heavy crude oil. journal of petroleum science research (jpsr), 3(3), pp.130–135. 11gaba, m. & dhingra, n., 2011. microwave chemistry: general features and applications. indian journal of pharmaceutical education and research, 45(2), pp.175–183. 12britten, a.j., whiffen, v. & et al., 2005. heavy petroleum upgrading by microwave irradiation. journel of wit transactions on modelling and simulation, 41, pp.103–112. 13mamoun, m., 2015. impact of american petroleum institute standards variation on crude distillation unit khartoum. thesis, sudan university of science and technology. 14merckel, r., 2014. fast and microwave-induced pyrolysis biooil from eucalyptus grandis: possibilities for upgrading. thesis, university of pretoria. 15hussain, h.k., ali, s.m. & ali, y.m., 2011. upgrading sharky baghdad heavy crude oil. alkhwarizmi engineering journal, 7(3), pp.19–29. 16mohammed, i.a. & et al., 2011. upgrading heavy crude oil potentials through microwave assisted distillation. journel of engineering and science, 2(3), pp.137–147. http://www.abeq.org.br/bjche http://www.npc.org/ hussein qasim hussein and zeina abbas khedheer -available online at: www.iasj.net ijcpe vol.18 no.4 (dec. 2017) 13 17vazquez, l.o.a., domínguez, j.l.c. & et al., 2012. effect of tetralin, decalin and naphthalene as hydrogen donors in the upgrading of heavy oils. journel of elsevier ltd, 42(august), pp.532–539. 18mohammed, a.d., isah, a.g. & et al., 2012. comparative study on sulphur reduction from heavy petroleum solvent extraction and microwave irradiation approach. international journal of energy and environment (ijee), 3(6), pp.949– 960. 19ammouri,q.m., 2010.the improvement of rheological properties of al – dura refinery asphaltic bindersusing diffrent addatives.thesis, baghdad university. 20miadonye, a., snow, s. & et al., 2009. desulfurization of heavy crude oil by microwave irradiation. journel of transactions on engineering sciences, 63, pp.455– 465. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol. 24 no.1 (march 2023) 1 – 4 eissn: 2618-0707, pissn: 1997-4884 *corresponding author: name: jules metsebo, email: jmetsebo@gmail.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. improving the recovery of hydrocarbons in a well in the gullfaks field by injecting sequestrated co2 andré cheage chamgoué a, colins leprince kombou b, merline tchouate ngankap c, jules metsebo d, *, and ateh armstrong akoteh e a school of geology and mining engineering, university of ngaoundere, p.o. box 115, meiganga, cameroon b far north court of appeal, ministry of justice, keepers of the seals, po. box 60, kaéle, cameroon c african higher institute of managerial and technological education, p.o. box 1743, bonanjo, douala, cameroon d department of hydraulics and water management, national advanced school of engineering, university of maroua, p.o box 46 maroua, cameroon e department of mechanical, petroleum and gas engineering, national advanced school of mines and petroleum industries, university of maroua, p.o. box 46 maroua, cameroon abstract the gullfaks field was discovered in 1978 in the tampen area of the north sea and it is one of the largest norwegian oil fields located in block 34/10 along the western flank of the viking graben in the northern north sea. the gullfaks field came on stream in 1986 and reached a peak of production in 2001. after some years, a decrease in production was noticed due to the decrease in pressure in the well. the goal of this paper is to improve the production of a well located in gullfaks field by injecting co2 through coiled tubing. the use of the co2 injection method is due to the fact that it is a greenhouse gas, and its production in the atmosphere contributes to global warming. it is important to reduce its emission into the atmosphere and to boost the production of oil in the well. the co2 is injected through the coil tubing to lighten the hydrostatic column and allow the fluid to move from the tubing to the surface. the completion and pvt data are processed in pipesim and prosper softwares. by integrating a number of calculations by using the nodal analysis methods and gas injection methods, the results obtained show that the well is not producing and by injecting sequestrated co2 at the flow rate of 1.482 mmscft/d with an injection pressure of 2500 psig, the oil flow rate provided by the coiled tubing gas injection is 900 stb/d. the profitability of the project is achieved over a period of 20 years with a net present value (npv) of $11948858.5 and a return on investment after 5 years 2 weeks. keywords: gullfaks field, coiled tubing, injecting sequestrated co2, pipsim software, prosper software, economic analysis. received on 12/12/2022, received in revised form on 06/02/2023, accepted on 07/02/2023, published on 30/03/2023 https://doi.org/10.31699/ijcpe.2023.1.1 1introduction the gullfaks field is one of norway's largest oil fields located in block 34/10 along the western flank of the viking graben in the northern north sea [1-3]. it is a structural complex with reservoirs in several strata, fragmented by numerous faults [4-6]. it was discovered in 1978 in the tampen region of the north sea; it was put into production in 1986 and reached peak production in 2001 [7-9]. however, the improvement of the production forecasts of an oil field constitutes one of the concerns of the production engineer within the oil companies. it is also one of the lines of action envisaged by oil companies [10-12]. as soon as the gullfaks field began production in 1986, a drop in production was noticed due to the depletion of the reservoir. after primary and secondary recovery carried out, it was observed that the reservoir still contained a considerable amount of hydrocarbons that could be exploited [5-7]. this made it possible to use assisted recovery techniques. among assisted recovery techniques: heat injection accounts for 39%, gas injection accounts for (60%), and chemical injection accounts for (1%) [14-16]. although these techniques make it possible to recover hydrocarbons efficiently and profitably, they are very expensive and the scarcity of products to be injected into the wells must be taken into account. some work in the literature has used a new approach based on enhanced hydrocarbon recovery by injection of sequestrated co2 to boost production while reducing co2 emission into the atmosphere [17-24]. the recovery of hydrocarbons from co2 sequestration is a modern technique still very little used in the oil industry. this technique of enhanced hydrocarbon recovery is in the news since it demonstrates that it is possible to capture a good part of the co2 generated by oil exploitation and reinjection it into the well in order to reduce the carbon footprint carbon from these operations. in november 2022 during the cop (conference of the parties) 27 in sharm el scheik in egypt, there was a lot of talk about climate change and the harmful effect of the exploitation of fossil fuels on the climate. this study proposes to http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:jmetsebo@gmail.com http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2023.1.1 a. c. chamgoué et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 1 4 2 improve the recovery of hydrocarbons in a well of the gullfacks field using the injection of co2 sequestrated in the atmosphere. to achieve this, several objectives have been set: perform a nodal analysis to predict the performance of the well, justify the choice of the method, design gas injection by coil tubing in order to see the maximum depth of co2 injection and the flow injected and to make an economic analysis to predict the performance of the project. this paper consists of three sections. the first section covers the introduction. the second section describes the data, tools, methods used and results obtained. the third section is the conclusion. 2materials, methods and results completion data appears in table 1. table 1. completion data type of casing type of casingcasing type measure depth od (in) id (in) grade conductor 500ft 30 28 b surface 4000ft 22 20 x52 intermediate 8000ft 13.625 12.375 l80 production 9000ft 7 6.094 c95 tubing 8000ft 4.5 3.5 d95 the pvt data in table 2 are used for the nodal analysis which makes it possible to determine the differentiability of the reservoir, to materialize the flow model of the reservoir and the head losses in the well. table 2. pvt data settings values reservoir pressure 2500psi reservoir temperature 150°f water-cut 50% reservoir permeability 80 md drainage radius 800ft skin 2 reservoir height 300ft volume factor 1.3 oil viscosity 1.2 cp total compressibility 0.00009 psi-1 production decline rate 0.08 yr-1 oil density 35° api gas oil ratio 500 scft/stb gas density 0.65 the nodal analysis method, the coiled tubing gas injection method, the economic analysis method, pipesim software and prosper software are used to obtain the results in this paper from the data in table 1 and table 2. the design of the well in the initial state is presented in fig. 1. fig. 1 indicates that the hole layer connection is at 8500 ft which allows communication between the reservoir and the bottom of the well. the nodal analysis of the well in the initial state is shown in fig. 2. fig. 2 reveals that the ipr (inflow performance relationship) in red and the vlp (vertical flow performance) in blue do not intersect, which means that the well is not producing and not eruptive. to make the well eruptive, the gas injection method by coiled tubing is used because there is the presence of coiled tubing and separation gas in the site. this method is flexible at low maintenance cost and is used to produce acceptable oil flow usable for deep wells at high temperature with a vertical or horizontal profile. fig. 3 presents the design of co2 injection by coiled tubing. fig. 1. design of the well in the initial state fig. 2. initial state well performance curve fig. 3. pressure and temperature gradient curve fig. 3 shows the maximum depth of gas injection which is 7999.9 ft at this level we observe a drop in pressure at the bottom of the well due to the gas which lightens the hydrostatic column of table 3. the oil flow and the water flow rate are the same in table 3 because the water cut is 50%. after injecting co2 a. c. chamgoué et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 1 4 3 into the well, it is necessary to do a second nodal analysis to see the new performance of the well as shown in fig. 4. table 3. results of the co2 injection design by coiled tubing parameters values liquid flowrate 916.9 stb/d gas flowrate at co2 injection 1.482 mmscft/d co2 injection pressure 2500 psig oil flowrate 458.45 stb/d water flowrate 458.45 stb/d fig. 4. well performance curve after co2 injection according to fig. 4, the curves of ipr and vlp meet which shows that the well-produced thanks to the injection of co2 which decreased bottom pressure to below reservoir pressure (as shown table 4). this meeting point is called the operating point, which is the net flow produced by the well. table 4. results of the nodal analysis of the well after co2 injection parameters values liquid flowrate 1800 stb/d oil flowrate 900 stb/d water flowrate 900 stb/d reservoir pressure 2500 psi the oil flow and the water flow rate are the same in table 4 because the water cut is 50%. the operator's objective is to produce at a rate greater than or equal to 200 stb/d because below this rate, the well is no longer economically profitable. the exponential model predicted the decline in production over time as shown in fig. 5. fig. 5. production decline curve from fig. 5, the flowrate produced at year 19 is less than 200 stb/d. so, the economic balance sheet is made in 20 years. expenses consist mainly of capex and opex according to table 5. table 5. capex and opex expenditure parameters values purchase of the compressor $15000 purchase of coiled tubing $80,000 water treatment cost $20000 cost to produce a barrel of oil $17050242.9 total tax 83812045.1$ total energy cost $182,500 maintenance cost 25000$ in table 5, the purchase of the compressor and the coiled tubing are approximate values. the cost of water treatment is estimated based on the price of water treatment used by oil company perenco. we used the number of barrels produced per day, multiplied by 15$ which is the price we spend to produce a barrel of oil and multiplied by 365 days to have the cost we spend to produce a barrel of oil/year. the cost of energy/day is estimated at 20 to 35$/day so to have the total cost in energy we made 20$ *365*20 since we produce in 20 years. the maintenance costs are estimated based on the maintenance costs of oil companies as haliburton and schlumberger. we first calculate the cash flow=cross revenue – expense and then the net cash flow = cash flow – tax. expenses during the 20 years of production are estimated to be worth $17,300,742.9. revenues are essentially based on hydrocarbon sales, with a barrel price estimated at $87. during this 20-year period, revenues are estimated at $296,674,226. the npv is estimated to be $11948858.4. the project is profitable because npv is positive. the return on investment is 5 years 2 weeks. 3conclusion this paper focuses on improving the recovery of hydrocarbons in a well in the gullfaks field by injecting co2 sequestrated by the coiled tubing. the nodal analysis of the well at the initial state showed that the well is noneruptive. after injecting co2 into the well at a rate of 1.482 mmscft/d with a pressure of 2500 psi, the oil flowrate obtained is 900 stb/d. the economic analysis gives a gross profit of $11948858.4 after 5 years and two weeks. however, as one produces the viscosity of the fluid increases in the reservoir and the capillary force increases. which can be due to the fact that, the wettability tends to load pushing the oil to become residual. in this case the oil no longer comes near the well while this method of injection into the well becomes inappropriate so the solution is to inject carbon dioxide rather in the oil zone to reduce the viscosity of the oil and allow it to be swept. in order to make carbon dioxide injection recovery even more efficient and profitable, the following recommendations will be perfect: use nitrogen in case of corrosion caused by co2, reduce the carbon footprint of the industry by storing more co2, redo the sensitivity analysis if there is a change in a parameter and have a stable energy source. a. c. chamgoué et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 1 4 4 references [1] fossen, h., hesthammer, j. structural geology of the gullfaks field, departement of geology, university of bergen, 231-261 (1998), https://doi.org/10.1144/gsl.sp.1998.127.01.16. [2] hesthammer, j., and fossen, h. structural core analysis from the gullfaks area, northern north sea, marine and petroleum geology, v. 18, p. 411-439 (2001), https://doi.org/10.1016/s02648172(00)00068-4. [3] petterson, o., storli, a., ljosland, e., nygaard, o., massie, i., carlsen, h. the gullfaks field, giant oil and gas fields ofthedecade 1978-1988, p. 429-446 (1992), https://doi.org/10.1306/m54555c26. [4] agostini, s. a study of the grid orientation effect in the gullfaks brent reservoir simulation model, a report of the department of earth science and engineering center for petroleum studies, imperial college london, p. 8 (2011). [5] tollefsen, s., graue, e., and svinddal, s. the gullfaks field development challenges and perspectives, european petroleum conference, society of petroleum engineers, 48p (1992), https://doi.org/10.2118/25054-ms. [6] fossen, h. indication of transpressional tectonic in the gullfaks oilfield, marine petroleum geol. 6, 2230 (1989), https://doi.org/10.1016/02648172(89)90073-1. [7] aduomahor, o, b., umeagu, e., ogundusi, o., equere, i. (2017). investigating the impact of different reservoir property modeling algorithms and their associated uncertainties on volume estimation, gullfaks field, north sea, p. 23. [8] fossen, h., & and rørnes, a. properties of fault populations in the gullfaks field, northern north sea: journal of structural geology 18, p. 179-190 (1996), https://doi.org/10.1016/s01918141(96)80043-5. [9] graue, e., helland-hansen, w., johnsen, j., lømo, l., nøttvedt, a., rønning, k., & ryseth, ar advance and retreat of brent delta system, norwegian north sea: in: brooks, j & gibbis. ad (eds) petroleum geology of north west europe, p. 915-937 (1987). [10] ncib, o. the different methods of oil recovery, p. 319 (2021). [11] lyons, wc, and plisga, gj standard handbook of petroleum and natural gas engineering (2004). [12] s. john, forecasting oil and gas producing for unconventional wells, 2nd ed., petro. denver (2018). [13] cs hsu and pr robinson, petroleum science and technology, springer, cham, first edition (2019). [14] gozalpour, f., ren, sr, and tohidi, b. (2005). co2 eor and storage in oil reservoirs. oil & gas science and technology rev. ifp 60(3), 537-546, https://doi.org/10.2516/ogst:2005036. [15] r. john and l. richard, introduction to petroleum engineering. wiley, new jersey (2017). [16] f. jahn, m. cook, & m. graham. hydrocarbon exploration and production. (d. i. 46, ed.) amsterdam, the nertherlands: elsavier (2003). [17] actu, e. sequestering co2, a transition solution pending large-scale development, 5-15 (2004). [18] bachu, s. evaluation of co2 sequestration capacity in oil and gas reservoirs in the western canada sedimentary basin, alberta geological survey. 852863 (2004). [19] metz, b., davidson, o., de coninck, h., loos, m., meyer, l. special report on carbon dioxide capture storage, cambridge university press, 443 p (2005). [20] de visser, e., hendriks, c., barrio, m., mølnvik, mj, de koeijer, g., liljemark, s. and le gallo, y. dynamis co2 quality recommendations. international journal of greenhouse gas control 2, 478-484 (2008), https://doi.org/10.1016/j.ijggc.2008.04.006. [21] attavitkamthorn, v., vilcáez, j. and sato, k. integrated ccs aspect into co2 eor project under wide range of reservoir properties and operating conditions, 601-602 (2013), https://doi.org/10.1016/j.egypro.2013.06.622. [22] portman, l., the science and economics behind coiled-tubing-string design and optimization, spe/icota coiled tubing roundtable, houston, 2526 may (1999), https://doi.org/10.2118/54456-ms. [23] mcclelland, g. and global tubing, innovative coiled tubing technology to improve performance in horizontal completions, spe/icota coiled tubing & well intervention conference & exhibition, the woodlands, texas, usa, march (2013), https://doi.org/10.2118/163892-ms. [24] livescu, s., craig, s.; watkins, t., smaller coiled tubing diameter achievable by the use of lubricants, international petroleum technology conference, kuala lumpur, malaysia, paper number: iptc-17815-ms december (2014), https://doi.org/10.2523/iptc-17815-ms. https://doi.org/10.1144/gsl.sp.1998.127.01.16 https://doi.org/10.1016/s0264-8172(00)00068-4 https://doi.org/10.1016/s0264-8172(00)00068-4 https://doi.org/10.1306/m54555c26 https://core.ac.uk/download/pdf/77002474.pdf https://core.ac.uk/download/pdf/77002474.pdf https://core.ac.uk/download/pdf/77002474.pdf https://core.ac.uk/download/pdf/77002474.pdf https://core.ac.uk/download/pdf/77002474.pdf https://doi.org/10.2118/25054-ms https://doi.org/10.1016/0264-8172(89)90073-1 https://doi.org/10.1016/0264-8172(89)90073-1 https://doi.org/10.1016/s0191-8141(96)80043-5 https://doi.org/10.1016/s0191-8141(96)80043-5 https://pascal-francis.inist.fr/vibad/index.php?action=getrecorddetail&idt=7744018 https://pascal-francis.inist.fr/vibad/index.php?action=getrecorddetail&idt=7744018 https://pascal-francis.inist.fr/vibad/index.php?action=getrecorddetail&idt=7744018 https://pascal-francis.inist.fr/vibad/index.php?action=getrecorddetail&idt=7744018 https://pascal-francis.inist.fr/vibad/index.php?action=getrecorddetail&idt=7744018 https://pascal-francis.inist.fr/vibad/index.php?action=getrecorddetail&idt=7744018 https://books.google.iq/books?hl=en&lr=&id=h-drjbci08qc&oi=fnd&pg=pa1&dq=standard+handbook+of+petroleum+and+natural+gas+engineering+(2004).&ots=5k3_9fyyhf&sig=y6-tgvw05ujf-w4gfhrat3xknaw&redir_esc=y#v=onepage&q=standard%20handbook%20of%20petroleum%20and%20natural%20gas%20engineering%20(2004).&f=false https://books.google.iq/books?hl=en&lr=&id=h-drjbci08qc&oi=fnd&pg=pa1&dq=standard+handbook+of+petroleum+and+natural+gas+engineering+(2004).&ots=5k3_9fyyhf&sig=y6-tgvw05ujf-w4gfhrat3xknaw&redir_esc=y#v=onepage&q=standard%20handbook%20of%20petroleum%20and%20natural%20gas%20engineering%20(2004).&f=false https://books.google.iq/books?hl=en&lr=&id=mj2gdwaaqbaj&oi=fnd&pg=pr5&dq=%5b13%5d%09cs+hsu+and+pr+robinson,+petroleum+science+and+technology,+springer,+cham,+first+edition+(2019).&ots=b54a0h9-k8&sig=ze-vg5kskrkup8a_ci_mxlevyts&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=mj2gdwaaqbaj&oi=fnd&pg=pr5&dq=%5b13%5d%09cs+hsu+and+pr+robinson,+petroleum+science+and+technology,+springer,+cham,+first+edition+(2019).&ots=b54a0h9-k8&sig=ze-vg5kskrkup8a_ci_mxlevyts&redir_esc=y#v=onepage&q&f=false https://doi.org/10.2516/ogst:2005036 https://books.google.iq/books?hl=en&lr=&id=dbipdqaaqbaj&oi=fnd&pg=pp13&dq=%5b15%5d%09r.+john+and+l.+richard,+introduction+to+petroleum+engineering.+wiley,+new+jersey+(2017).&ots=ahanjjtjkp&sig=anihpkftfz4r3na2_fr-bvxy0ka&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=dbipdqaaqbaj&oi=fnd&pg=pp13&dq=%5b15%5d%09r.+john+and+l.+richard,+introduction+to+petroleum+engineering.+wiley,+new+jersey+(2017).&ots=ahanjjtjkp&sig=anihpkftfz4r3na2_fr-bvxy0ka&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=ocut8hedu1ac&oi=fnd&pg=pp1&dq=hydrocarbon+exploration+and+production&ots=xrgxd0l2pg&sig=zi42jbyfhlnc98spe6xy3ypcslm&redir_esc=y#v=onepage&q=hydrocarbon%20exploration%20and%20production&f=false https://books.google.iq/books?hl=en&lr=&id=ocut8hedu1ac&oi=fnd&pg=pp1&dq=hydrocarbon+exploration+and+production&ots=xrgxd0l2pg&sig=zi42jbyfhlnc98spe6xy3ypcslm&redir_esc=y#v=onepage&q=hydrocarbon%20exploration%20and%20production&f=false https://books.google.iq/books?hl=en&lr=&id=ocut8hedu1ac&oi=fnd&pg=pp1&dq=hydrocarbon+exploration+and+production&ots=xrgxd0l2pg&sig=zi42jbyfhlnc98spe6xy3ypcslm&redir_esc=y#v=onepage&q=hydrocarbon%20exploration%20and%20production&f=false https://repository.ubn.ru.nl/bitstream/handle/2066/230961/230961.pdf?sequence=1 https://repository.ubn.ru.nl/bitstream/handle/2066/230961/230961.pdf?sequence=1 https://repository.ubn.ru.nl/bitstream/handle/2066/230961/230961.pdf?sequence=1 https://doi.org/10.1016/j.ijggc.2008.04.006 https://doi.org/10.1016/j.egypro.2013.06.622 https://doi.org/10.2118/54456-ms https://doi.org/10.2118/163892-ms https://doi.org/10.2523/iptc-17815-ms iraqi journal of chemical and petroleum engineering vol.18 no.1 (march 2017) 17 36 issn: 1997-4884 preparations of organoclay using cationic surfactant and characterization of pvc/ (bentonite and organoclay) composite prepared via melt blending method basma a. abdul majeed and dhilal amer sabar chemical engineering department -college of engineering -university of baghdad-iraq abstract calcium-montmorillonite (bentonite) [ca-mmt] has been prepared via cation exchange reaction using benzalkonium chloride [quaternary ammonium] as a surfactant to produce organoclay which is used to prepare polymer composites. functionalization of this filler surface is very important factor for achieving good interaction between filler and polymer matrix. basal spacing and functional groups identification of this organoclay were characterized using x-ray diffraction (xrd) and fourier transform infrared (ftir) spectroscopy respectively. the (xrd) results showed that the basal spacing of the treated clay (organoclay) with the benzalkonium chloride increased to 15.17213 0 a, this represents an increment of about 77.9% in the basal spacing. ftir spectra illustrate that benzalkonium chloride compound was successfully intercalated in to clay layers. the results confirm the effectiveness of the synthesis of organoclay with similar characteristics compared to those ones observed in the bentonite. the features were obtained by a simple process and enable interaction with organic compounds (polymers and plastic). pvc/bentonite composite and pvc/organoclay composite were prepared by the melt intercalation method .the results have been analyzed and compared for pvc samples with (3wt%, 7wt% and 12wt %) bentonite and organoclay micro filler .mechanical properties, thermal properties, flammability and water absorption percentage of prepared samples were tested. mechanical characteristic such as tensile strength, elongation at break, hardness and impact strength (charpy type) were measured for all samples, where the tensile strength and elongation at break of pvc composites increased with increasing organoclay loading compared with unmodified bentonite. also, the hardness and impact strength of the composites increase with increase in filler content. thermal properties of pvc/ (bentonite, organoclay) composites were characterized using differential scanning calorimeter (dsc) and thermal conductivity analyzer. the results showed tg shifted toward higher temperature for all type of filler compared to neat pvc. also, thermal conductivity measurement values illustrated that pvc/bentonite composites have a good thermal insulation at 12wt%, thermal conductivity was decreased from 0.222 w/m.k for neat pvc to 0.11 w/m.k at 12wt% pvc/bentonite composites. organoclay give the best possible water absorbability of the pvc, with other word making it moisture resistant .the higher the filler content the higher burning time, the lower rate of burning and the lower height of the flame which are evident at 12wt% for all fillers. university of baghdad college of engineering iraqi journal of chemical and petroleum engineering preparations of organoclay using cationic surfactant and characterization of pvc/ (bentonite and organoclay) composite prepared via melt blending method 18 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net key words: pvc composites, bentonite, organoclay, benzalkonium chloride, cationic surfactant , cation exchange capacity and melt blending method. introduction the polymer is a word of a greek origin where “poly” is a synonym of ”many”, while “meres” stands for “parts”, so a polymer is a large molecules consisting of repeated smaller size chemical units. they can be made into types of final products as it is the case with the pure (new) form. nonetheless, to make an effectively useful polymer, it is indispensable to modify it, particularly when the major limitations in the unmodified polymer are taken into account. among those restrictions may be the low stiffness, low strength and the lack of stability when exposed to light rays, heat and radiation that can ionize. to make them vastly usable in different industrial fields nowadays, improved polymer composite productions are the right pathway to overcome the evident restrictions on one hand, and to insure the production of high quality polymers on the other. a composite is defined as the combination at microscopic level between a couple (and more) of particular materials with a specific interference to link them together. the material could be of a metal, ceramic or polymer nature [1]. nowadays, poly vinyl chloride occupies the third position in the list of the most commonly produced plastics, where the polyethylene comes at the top followed by polypropylene, by virtue of its valuable characteristics, wide applications, barrier properties, low cost and high chemical resistance. pvc is in the form of powders, slurries, liquids, and tablets. it has a wide range of properties of colors, solid , rigid, and stiff materials (with high viscosity) at room temperature, light weight with a good resistance to bases & acids, alcohol, oils, compound hydrocarbon aliphatic. pvc has relatively low cost, biological and chemical resistance and workability and can be formed easily. for these reasons it is used for a wide range of applications, such as insulation on electrical cables, solid pipe manufacturing, window frames and doors, bottles, containers, furniture industry, etc. [2]. the thermal stability and processing of poly vinyl chloride, on the other hand, are unimportant in comparison with familiar polymers .these properties can be improved by making the poly vinyl chloride compound with some additives. the most commonly used additives in pvc are lubricants, heat stabilizers, plasticizers, fillers and pigments. either polymerization or melt blending processes are used [3, 4]. bentonite, which is predominantly montmorillonite clay, montmorillonite is of a 2:1 layered structure pattern, a monoaluminumlayer of octahedral plate inserted between two layers of silicon tetrahedral plates. the primary unit in the outer tetrahedral plates is the silicon oxide tetrahedron sio4 where the silicon atom is bonded to four oxygen atoms [5]. the isomorphous replacement of al +3 for si +4 in the tetrahedral layer and mg +2 for al +3 in the octahedral layer causes the charge of the clay surface to be a negative one. this lack of balance in the charge is caused by exchangeable cations, usually the clay surface na + and ca +2 [2]. the layered structure of the clay contributes to the expansion following hydration. na + and ca +2 ions with the existence of http://www.iasj.net/ basma a. abdul majeed and dhilal amer sabar -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 19 water cause the clay surface to become hydrophilic medium [5, 6]. that is why, natural bentonite is considered to be a hydrophilic material. so, it is not compatible with organic materials such as polymers and plastics. by converting it to organoclay, it will, actually, be transformed into a hydrophobic material whichin this caseis more compatible with organic materials [7, 8]. it is the most familiar layered silicate in use because of its abundance in nature and useful properties (high surface area, high cation exchange capacity and large aspect ratio). it finds usage, as filler, for composites [9]. due to the existence of the –oh groups at the clay surface, it is important to modify it using the organic surfactant so as to make it compatible with polymer matrix [10]. the surface properties of natural bentonite can be greatly modified by simply ion-exchange reactions. organoclay is normally made by replacing the alkali cations with alkylammonium [11]. this cation exchange widens the inter-gallery distance in addition to changing the surface polarity of the clay. the latter is extremely important for the wanted intercalation phenomena, as it becomes easier for the polymer chain to access the space of the organoclay inter-layers [12]. quaternary ammonium salts are the most commonly used organic compounds to modify clays. they represent a form of an organic nitrogen compound, where a central nitrogen atom joined to four organic groups together with an acid radical included in the molecular structure [11, 13 and 14]. also, they are all considered to be surface-active coordination compounds and tend to be adsorbed on surfaces; this is where their name (surfactants) comes from. by exchanging ions, the surface properties variation from hydrophilic to hydrophobic [6]. this cation replacement alters not only the surface polarity of the bentonite but also widens the intergallery space. the latter is of paramount importance for the targeted intercalation phenomena, as the space between the layers of organoclay becomes more accessible for the polymer chain [12, 15]. the most widely used kinds of quaternary ammonium compounds to modify clays are dimethyl ammonium, methyl benzyl ammonium, and benzyl dimethyl ammonium and di benzyl methyl ammonium quaternary [16]. the nature of organoclay (ommt) was affirmed by x-ray diffraction (xrd), x-ray fluorosis (xrf) and fourier transform infrared (ftir) spectroscopy. it can be used in the composite materials as the filler for pvc. dibasic lead stearates (dbls), dibasic lead phosphate (dblp) are used as the stabilizer; stearic acid is used as a lubricant. dioctyl phthalate (dop) is used as a plasticizer for compounding. it is noticed that raising the pvc temperature to more than 70 °c imposes some absurd changes on its properties. in practice, when temperatures of (150-200 0 c) are used, sufficient degradation may occur upon normal processing operation which makes the product useless [17, 18]. xu et al. [19] gives a dioctyl phthalate (dop) as intercalator for organoclay and poly vinyl chloride because they discovered alkylammonium salts in between the interlayers of organoclay, could trigger pvc degradation. dop can impede the degradation of poly vinyl chloride. on the other hand yalcin & cakmak [5] searched the influence of dioctyl phthalate on the penetration of organoclay in a poly vinyl chloride matrix. it was noticed that dop http://www.iasj.net/ preparations of organoclay using cationic surfactant and characterization of pvc/ (bentonite and organoclay) composite prepared via melt blending method 20 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net increases the penetration of organoclay in a polymer matrix. the objective of this paper is to prepare a sample of organoclay by purifying bentonite and modifying it by quaternary ammonium salt and the produced bentonite was compared with the unmodified bentonite as filler for pvc. the effects of different modified bentonite (organoclay) (ommt) and unmodified bentonite loading on the mechanical and thermal properties; flammability and water absorption of poly vinyl chloride (pvc)/ ommt composites and poly vinyl chloride (pvc)/ unmodified bentonite composites respectively, were investigated. experimental work 1. materials the pvc powder, a suspension polymer, supplied by saudi basic industries corporation and kingdom of saudi arabia; the pvc used in this research has been analyzed by ftir. iraqi bentonite powder ((na, ca)(al ,mg)6(si4o10)3(oh)6nh2o) was brought from an iraqi quarry around the area suffra / the ministry of industry/the state company of geological survey and mining. the specifications of the bentonite are given in table 1 surfactant: benzalkonium chloride (c6h5ch2n (ch3)2r]cl )(r: n -c12h25) (quaternary ammonium chloride) was used to modify bentonite from hydrophilic nature to organophilic. benzalkonium chloride is produced by indian company/ sigma ultra. a solution of 50% concentration was prepared. additives such as dibasic lead stearates (dbls) (2pbo.pb (c17h35coo) 2), dibasic lead phosphate (dblp) (o8p2pb3) are used as the stabilizer; stearic acid (c18h36o2) is used as lubricant. these materials are from the ministry of industry/the state company of plastic industries/ baghdad plastic plant. dioctyl phthalate (dop) (c6h4-1, 2[co2 ch2 ch (c2h5) (ch2)3ch3]2) used in this study was used as a plasticizer by indian company/ sigma ultra. table 1: the characteristics of the bentonite 2. methods  bentonite washing (rinsing) bentonite has been washed and used for the preparation of organoclay as follows [20]: 500 g of bentonite were weighted by using sensitive electric balance, to separate the insoluble salts, an amount of 500 g bentonite was dispersed in 10 liters of tap water using electrical mixer, for 10 min. the mixture was left for 30 min to stagnate. the precipitate was rinsed with distilled water for several times to remove as much of the insoluble salts as possible using the same method. the mixture is filtered, dried in electrical oven at 80 o c, milled and sieved.  preparation of organoclay organoclay was prepared by adding the required quantity of quaternary characteristics value partical size 0.075 m cation exchange capacity(cec) meq/ 100g 80 chemical composition (wt% dry basis) silica(sio2) alumina(al2o3) ferric oxide(fe2o3) magnesium oxide(mgo) calcium oxide(cao) sodium oxide(na2o) potassium oxide(k2o) loss on ignition(l.o.i) p2o5 so3 56.77 26.2 8.12 3.42 4.48 1.11 0.6 0.49 0.65 0.59 http://www.iasj.net/ basma a. abdul majeed and dhilal amer sabar -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 21 ammonium chloride solution (benzalkonium chloride 50% solution) (alkyl benzyl dimethyl ammonium chloride) to the desired quantity of rinsed bentonite thoroughly by hand .the amount of consumed quaternary ammonium versus cec% of mineral clay are given in table 2. cation dosages varied in range from 0 to 150% cec. the suitable equation for brevity is: a=0.30 b, where b is cec% and a is (g benzalkonium chloride/100g bentonite) [7, 21]. the produced paste was then introduced into the electrical mixer for (1hr) and collected in a container. all organoclay products were washed three times with deionized water to remove excess surfactants, filtered and dried at room temperature or in the electrical oven at 60-80 0 c for two days, ground in agate mortar followed by screening to particle size 0.075m [22]. table 2: amounts of quaternary ammonium used for preparation of organoclay cec % 100 g (benzalkonium chloride)/100g bentonite 30  sample preparation the following couple of steps summarize the production of poly vinyl chloride composite [23]: in the first one, 1% by weight of the stabilizer (dibasic lead stearate, dbls and dibasic lead phosphate, dblp) were added to the pvc powder. 1% by weight of the stearic acid as a lubricant was also added. in addition to that, a mounts of 3%, 7% and 12% by weight of the filler were added. the filler used were bentonite and organoclay. the blend was mixed in a high_ speed mixer for 20min forming a dry mixture. in the second step, the dry blend was blended with 20% by weight dioctyl phthalate (dop). the details of additives percentage are given in table 3. the blending took place in the plastograph internal mixer (plasticcorder), (bra bender .gmbh & co. kg, duisburg, germany, 0-1000 0 c) at (65-80 0 c) for 20 min and a 64rpm mixing speed. table 3: pvc composite formulation with filler composition (%) material 1 2 3 4 pvc 100 100 100 100 stabilizer :dbls 1 1 1 1 stabilizer :dblp 1 1 1 1 lubricant: stearic acid 1 1 1 1 plasticizer :dop 20 20 20 20 bentonite 0 3 7 12 organoclay 0 3 7 12  compression molding (hot press) a hydraulic press (made in englan, noore, birmingham and serial number /d369) was used to mold the sheets to be tested in this study. it consisted of lower and upper moving platens. a sample of the above mentioned mold was wrapped by an aluminum thin sheet [1]. using the controlled hydraulic ram, the lower platen was pushed toward the upper platen causing the mold to close and putting it under pressure. the compression of the resulting film took place under the following conditions; a temperature of (170-185 0 c), and a pressure of (10 bars) for (7 min). when the seven minutes passed, the pressure was removed letting the lower platen to fall down under the effect of gravity. the mold was dismantled rapidly and running water was used to cool it down. the aluminum foil paper was neatly un-wrapped to clear the produced film sample out of it. the compression-molded sheets of 90gm weight and 180 * 180 mm size with 5mm thickness were fabricated [24]. measurements 1. clay measurements the natural bentonite and prepared organoclay were analyzed by: http://www.iasj.net/ preparations of organoclay using cationic surfactant and characterization of pvc/ (bentonite and organoclay) composite prepared via melt blending method 22 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net  x-ray diffraction (xrd) x-ray diffraction analysis was carried out to confirm the interspacing of the used bentonite and also to confirm whether the organoclay was formed or not. xrd performed by the powder method using a shimadzu xrd-6000 diffractometer (with cu-kα radiation, 40 k – 40 ma, the scan speed of 0.05 2ө/s and 5 seconds per step).  infrared spectroscopy (ftir) fourier transformation infrared spectrophotometer (ftir) was performed by the kbr method with a shimadzu ftir-8400 s spectrophotometer.  x-ray fluorosis (xrf) the xrf performed by spector, analytical instruments, boschstra be 10, d_47533 kleve /model: xepos /type: 76004814, s/n: 4l0058. 2. mechanical properties  tensile strength and elongation at break mechanical properties of the polymer blends films were measured on a shimadzu autograph in air at room temperature. tensile strength and elongation at break point were measured using a universal testing machine (tension_ compression to 5kn; manufactured by tinius olsen (uk).the compressed sheets were cut into dumbbell-shaped specimens according to astm d647-68.  hardness the hardness of all specimens was read and recorded; using a vickers diamond indenter (digital micro hardness tester), hvs– 1000.vickers indentation is a valid tool for evaluating the hardness of polymers. with a load of 0.4403 n. the load is applied for 20s (astm standard “test method for vickers hardness”, 1997). for every specimen, three readings were taken in accordance with polymeric matrix composite (pvc) astm-02240-97 for hardness test. the hardness value was determined by the penetration of the durometer indenter foot into the specimen. the sample was placed on a flat surface on the pressure foot of the instrument. a calibrated spring in the durometer applies a specific pressure to an indenter foot parallel to the surface of the specimen.  impact strength impact test sample specimens where fabricated by the standard specification [astm-e23] and which are appropriate for testing by the impact device type charpy (produced by (tokyo koki seizosho, ltd) company). the depth of the groove in the samples is 5mm with the groove base radius of 25mm and a groove angle 45 0 .for the purpose of identifying the extent of impact strength which the composite material is capable of withstanding; equation 1 is used: …(1)  water absorption of the composites samples water absorption test was performed according to astm d570-99 (standard test method for water absorption of plastics, 1998) by conditioning and weighing the sample. each sample was immersed in distilled water in a transparent thermoplastic container and covered with the lid for 24 hr at 27 0 c. excess water on the sample surface was wiped off with a filter paper before reweighing [1]. from equation 2 it was seen the percentage increase in mass during immersion was calculated using the equation: http://www.iasj.net/ basma a. abdul majeed and dhilal amer sabar -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 23 % water absorption = [(wet weight dry weight)/ dry weight] * 100 …(2) wet weight: is the weight of sample after immersing in water for 24 h (g). dry weight: is the initial weight of sample (g). 3. thermal properties  differential scanning calorimeter (dsc) the thermal properties of the composites were determined by differential scanning calorimeter dsc measurements performed using a shimadzu dsc-50, japan, at a heating rate of 10 o c/min in the temperature range 25-250 0 c under nitrogen purge. the glass transition temperature was taken as the midpoint of the transition.  conductivity measurement (k, and cp) thermal conductivity measurements were done using setaram, instrumentation, kep technologiestherm tci tm , and thermal conductivity analyzer/made in france. the mathis tc i is based on the modified transient plane source technique. it uses a one-sided, interfacial, heat reflectance sensor that applies a momentary, constant heat source to the sample. both thermal conductivity and effusivity are measured directly and rapidly, providing a detailed overview of the thermal characteristics of the sample material. sample material can be a solid, liquid, paste or powder [25, 26]. from equation 3 the heat capacity values of polymer composite [27] can be determined from the effusivity value equation by: =√ …(3) flammability  burning speed measurement test [to measure the time required for burning until a full self-extinguish take place using 164 (astm: d_635)] this method is considered as an internationally adopted one and is used to measure the flame dispersing speed in the different polymer material and to calculate the time duration needed for the burning. it is vastly used in polymer material convertible into plates, sheets or bars. polymers testable in this method are categorized to be flammable and selfextinguishable after a certain time of burning according to astm: d_635.  flame height measuring using the test 165 (astm: d-3014) this test is one of the lab methods used to measure the flame height a burning polymer can make. it is vastly used in polymer material convertible in to plates, sheets or bar. results and discussion 1. clay measurement  x-ray diffraction (xrd) figures 1 and 2 shows the xrd analysis of natural iraqi bentonite and prepared organoclay, respectively. from the xrd, the interlayer spacing of the pristine of natural bentonite and prepared organoclay, as shown in figures 1 and 2. the peak data lists of these figures are given in table 4 and 5 respectively. the organoclay and natural bentonite were previously dried at 60-80 0 c. the properties of organoclays were investigated by basal x-ray diffraction analysis. considering there figures, it can be shown that the benzalkonium salt is introduced in the spaces of the silicate; and this is done via a reaction of an exchange of cations [9, 21 and 28]. the basal http://www.iasj.net/ preparations of organoclay using cationic surfactant and characterization of pvc/ (bentonite and organoclay) composite prepared via melt blending method 24 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net spacing increased from 3.34264 to 15.17213 å, with 77.9% increase [29]. the interlayer spaces are greater in the case of the organoclay, showing the formation of intercalated structure. this behavior was confirmed by valenzuela diaz fr. [30] and caroline et al. [31]. to increase these spaces, two factors are considered: (i) large hydrophobic groups are present; (ii) the bentonite surface energy is decreased [32]. fig. 1: xrd of natural iraqi bentonite fig. 2: xrd of prepared of organoclay table 4: peak data list of natural iraqi bentonite no. 2theta (deg) d ( o a) i/i1 fwhm (deg) intensity (counts) integrated int(counts) 1 26.6467 3.34264 100 0.15960 602 2138 2 11.6813 7.56961 38 0.15240 231 821 3 29.4167 3.03388 29 0.17870 174 763 table 5: peak data list of organoclay no. 2theta (deg) d ( o a) i/i1 fwhm (deg) intensity (counts) integrated int(counts) 1 5.8204 15.17213 100 1.32500 454 13015 2 26.6421 3.34321 46 0.75450 207 2978 3 20.8105 4.26501 22 1.18000 101 2691  fourier transformation infrared spectrophotometer (ftir) of bentonite and organoclay the range of 4000 to 400 cm -1 shows the absorption of infrared radiation. the fourier transformation infrared spectrophotometer (ftir) of natural iraqi bentonite is shown in figure 3. iraqi natural bentonite has vibration peaks at 470.60 and 1114 cm -1 . this clay has a stretching and bending structure of si-o-si and si-o-al. si-o stretching peak at 1037.63 cm -1 and sihttp://www.iasj.net/ basma a. abdul majeed and dhilal amer sabar -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 25 o bending peak at 518.82 cm-1 are also presented. this is shown by gonzaga et al., [28]. the h-o-h bending region which corresponding to absorbed water is 1600-1700 cm -1 , while the stretching region of 3100-3700 cm -1 represents the o-h symmetric and asymmetric, this is shown by the results of bertagnolli & silva [33]. fig. 3: infrared curve of natural iraqi bentonite figure 4 shows the fourier transformation infrared spectrophotometer (ftir) of organoclay. ft-ir spectra of organoclay shows the peaks at 2854.45 and 2925.8 cm-1 which correspond to the organic matter .it also shows the presence of the additional band at 1434.94, 1456.16 and 1469.66 cm -1 compared to bentonite. the stretching vibrations of the c_h bonds occurred in the 2800-2900 cm -1 region. the symmetric and asymmetric stretching _ch [_ch2 and _ch3 stretching respectively] are shown by the absorption bands of 2854.45 and 2925.81 cm -1 [32, 34]. the asymmetric angular deformation of the ch3 groups occurs at about 1434.94 and 1379.01 cm -1 and of the ch2 groups occurs at about 1456.16 cm -1 [33]. fig. 4: infrared curve of prepared of organoclay it was found by [35] that the absorption bands at 1359.72 cm -1 correspond to aromatic tert. amines (cn) vibration and at 1633.59 and 1643.24 cm -1 correspond to n-h deformation. also, it can be shown the indication of vibrational bond and the presence of a http://www.iasj.net/ preparations of organoclay using cationic surfactant and characterization of pvc/ (bentonite and organoclay) composite prepared via melt blending method 26 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net modifying organic matter, with no distortion of the clay structure. this is evident also from the results of sulayman and kshash [21], bhattacharya and aadhar [32]. the ch3, ch2, ch, n-h and c-n vibration bonds in the infrared spectra of organoclay are good evidence. also, the intercalation of alkyl ammonium in the interlayer galleries of the clay is very clear [21, 28, and 36].  fourier transformation infrared spectrophotometer (ftir) of poly vinyl chloride the ftir spectra for poly vinyl chloride are shown in figure 5; poly vinyl chloride can be confirmed from the peak near 600 cm -1 , due to c-cl stretching vibrations [37] .the characteristic vibration peak of poly vinyl chloride between 570-760 cm -1 [35], so 599.82, 632.61, 684.88 and 692.40 cm -1 corresponding to the c-cl stretching vibrations. fig. 5: infrared curve of poly vinyl chloride  x-ray fluorosis analysis of bentonite and organoclay an xrf test was performed for bentonite, rinsed bentonite and organoclay. it was found that the cl content is getting smaller (from 0.2740 to 0.1364) for the rinsed bentonite (compared to) raw bentonite (nonrinsed).it was also found that the cl content increased in the organoclay (as compared to) the rinsed bentonite (from 0.1364 to 0.3084). this indicates that a reaction has taken place. 2. mechanical properties  tensile strength and elongation at break the effect of filler loading on mechanical properties of pvc composites is shown in figures 6, 7 and table 6. the tensile strength and elongation at break of pvc composites based on organoclay as compared with unmodified bentonite were found to be increased with increasing organoclay loading. the enhancement in the tensile and elongation at break of pvc composites is very clear using organoclay compared to bentonite. this may be due to the functionality of the organoclay which activated the pvc matrix and the organoclay to be intercalated and it was due to the good distribution of organic filler in (pvc) polymer matrix [3]. likewise, the increment in strength can also be attributed to the increasing in the ability of adhesion between the filler and the matrix leading to decrease the sliding between composite layers when applying stress in the composites [38, 39]. http://www.iasj.net/ basma a. abdul majeed and dhilal amer sabar -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 27 fig. 6: tensile strength curve of pvc/bentonite composite, pvc/organoclay composite fig. 7: elongation curve of pvc/bentonite composite, pvc/organoclay composite  hardness the test results for the hardness values for the basic pvc material reinforced with bentonite and organoclay as shown in figure 8, and given in table 6. the results show a significant improvement in the values of hardness for the different content of reinforcement. the 12% content showed the best hardness values. the difference in the result of hardness values for the reinforcing materials [bentonite, organoclay], is caused by the granular size of each of the materials. the lowest hardness value shown was found belonging to the case of bentonite content. the reason is due to the semi globular shape of its grains. similarly, the non-globular grain shape of the organoclay caused the hardness to be at the highest value [3]. this improvement in hardness was found to be more effective with organoclay as compared with bentonite and this is because the hardness of composite depends on the distribution of filler particles in the matrix [40]. fig. 8: hardness (shore a) of unfilled pvc, pvc/ (bentonite and organoclay composite) http://www.iasj.net/ preparations of organoclay using cationic surfactant and characterization of pvc/ (bentonite and organoclay) composite prepared via melt blending method 28 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net  impact strength from figure 9 and table 6, it can be seen that the impact strength value changes with the change of the content added to (bentonite and organoclay). it is noticed that the impact strength value increased for all types of fillers when compared with the neat pvc for which the value of the impact strength is 4.57 kj/m 2 . the larger the filler content added, the higher the impact strength value. the reason is attributed to the fact that the filler particles would bear the major part of the impact energy which the composite material is subjected to. thus the strength in question is improved. the increase in the reinforcement and toughness of pvc is due to the high dispersion and interface interaction [41]. the dispersion and interfacial properties of the organoclay are improved when the organoclay surfaces graft long organic chains. with the small amount of organoclay, it can disperse uniformly in the pvc matrix and have a good interface interaction with pvc matrix [38]. it was found that the best content of the organoclay is 12%wt added to the pvc. fig. 9: impact strength curve of unfilled pvc and pvc/ (bentonite and organoclay) composites  water absorption of the composites samples from figure 10 and table 6 it is noted that the organoclay was the best kind of fillers as it produced (for all its different content used; 3%, 7% and 12%wt) the best possible absorbability of the pvc .with other word making it moisture resistant. owing to its organic nature the organoclay is the best kind of clays as it is more compatible with the polymers which are already organic materials .in addition to the fact that the existence of the groups in question made the bentonite hydrophobic [1]. fig. 10: plots water content against percentage increase in filler http://www.iasj.net/ basma a. abdul majeed and dhilal amer sabar -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 29 table 6: mechanical properties of unfilled pvc, pvc-bentonite composites and pvc-organoclay composites sample designation tensile strength (mpa) elongation % shore a hardness impact strength (kj/m 2 ) % water uptake (after 24 h of immersion at 25 c 0 ) pvc neat 2.615 45.6 8.7 4.57 0.722 pvc-3% betonite 0.683 4.613 18.3 5.877 2.50 pvc-7% bentonite 0.3904 2.533 20.4 7.7 4.57 pvc-12% bentonite 0.2137 0.567 33.2 8.27 1.49 pvc-3% organoclay 0.728 0.995 19.4 8.47 0.66 pvc-7% organoclay 1.23 3.385 22.6 12.1 0.5 pvc-12% organoclay 1.879 14.35 40.3 15.7 0.4 3. thermal properties  differential scanning calorimeter (dsc) based on the data collected from the dsc thermo-gram as shown in figure 11 and given in table 7 the glass transition temperature was found out. whereas the fillers do fill and (patch) the gaps or spaces between the polymers chains, those restricting the chains movement to improve their plastic properties. the results showed t3%, t7%, t12% shifted toward higher temperatures for all type of filler compared to neat pvc. this improvement in thermal stability was found to be more effective with organoclay as compared with bentonite because of the dispersed organoclay can restrict the segmental mobility of pvc molecules. as a consequence, the increase of long organic chains contents is proportional to the increase of organoclay content. so the long organic chains improve the interface adhesion of bentonite and pvc matrix [10, 38]. fig. 11: plots glass transition temperature against percentage increase in filler  conductivity measurement (k, and cp) as the content of the organoclay filler increases so does the thermal conductivity as shown in figure 12, accompanied by the increase of thermal effusivity as shown in figure 13 and a decrease in heat capacity as http://www.iasj.net/ preparations of organoclay using cationic surfactant and characterization of pvc/ (bentonite and organoclay) composite prepared via melt blending method 30 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net shown in figure 14 and given in table 7. this is in agreement with the results of [27]. as for the bentonite, it is notice that with the increase in its content down the thermal conductivity decreases and the minimum value of thermal conductivity 0.11 w/m. k corresponds at the highest value (12% of bentonite content). when compared with 0.222 w/m.k value of the thermal conductivity of neat pvc, the thermal insulation of the product is improved with a ratio of 50.4% [2, 42]. so the higher the bentonite contents the lower the thermal effusivity and the greater heat capacity. fig. 12: thermal conductivity against filler content fig. 13: effusivity against filler content fig. 14: heat capacity against filler content http://www.iasj.net/ basma a. abdul majeed and dhilal amer sabar -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 31 table 7: thermal properties of unfilled pvc, pvc-bentonite composites and pvc-organoclay composites sample designation glass transition temp. (tg) ( 0 c) thermal conductivity value (k) (w/m. k) effusivity () (ws ½ / m 2 .k) heat capacity results cp (j/g.k) pvc neat 89.09 0.222 580.4 1083 pvc-3% bentonite 101.68 0.127 469.1 1203 pvc-7% bentonite 133.73 0.12 467.1 1212 pvc-12% bentonite 137.34 0.10 463.9 1388 pvc-3% organoclay 224.86 0.266 629.2 1294 pvc-7% organoclay 229.95 0.291 657.5 1246 pvc-12% organoclay 240.98 0.355 726.1 1038 4. flammability  burning speed measurement the results of the measurement showed a large increase in the burning time. it also showed a large decrease in the rate of burning for pvc/filler composite, with other words the higher the filler content, the higher burning time and the lower rate of burning which are evident in figures 15 and 16 and given in table 8. the best filler content was found to be 12% for all filler types where as the best filler among then found to be the 12% organoclay. this is agreement with the results of faris, a.h. [43]. fig. 15: the burning time against filler content fig. 16: rate of burning against filler content  flame height measuring the results of the measurement showed decrease in the flame height (h) for pvc/filler composite. this decrease in the flame height (h) is inversely proportional with the filler content in the neat pvc .with other words the higher the filler content, the lower rate of the flame height (h) which is evident in figure 17 and http://www.iasj.net/ preparations of organoclay using cationic surfactant and characterization of pvc/ (bentonite and organoclay) composite prepared via melt blending method 32 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net given in table 8. the best filler content was found to be 12% for all filler types where as the best filler among them was found to be the 12% organoclay [44]. fig. 17: flame height against filler content table 8: flammability properties of unfilled pvc, pvc-bentonite composites and pvc-organoclay composites sample designation burning time (min) rate of burning (cm/s) height of flame (mm) pvc neat 6 0.027 50 pvc-3% bentonite 7.5 0.022 45 pvc-7% bentonite 9 0.018 40 pvc-12% bentonite 12 0.013 35 pvc-3% organoclay 12 0.013 25 pvc-7% organoclay 15 0.011 22 pvc-12% organoclay 18 0.009 20 conclusion by analyzing the results obtained in this work, the following conclusions can be drawn: 1. the benzalkonium chloride was used to modify bentonite in an attempt to create susceptible clay to polymers and it was successfully incorporated in the montmorillonite clay. 2. from xrd results, it could be concluded that the organoclay (modified bentonite) presented larger basal distance than unmodified bentonite, because of intercalation of the ammonium quaternary salt in the inter-lamellar spaces of the clay. 3. the basal spacing of the montmorillonite clay was increased as a result of incorporating benzalkonium chloride and it was increased to 15.17213 0 a by the incorporating of quaternary ammonium. 4. from infrared spectroscopy results, the presence of ch2, ch3, n-h and aromatic tert. amines (c-n) vibration (groups) could be detected in the samples that modified the efficiency of the organophilization process. 5. considerable differences are noticed considering the xrd and ftir diagram of the prepared organoclay and natural bentonite. this is because of the exchange of quaternary ammonium with ca ++ ions at the surface of bentonite. http://www.iasj.net/ basma a. abdul majeed and dhilal amer sabar -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 33 6. increasing the organoclay loading increased the tensile strength and elongation at break of pvc composites compared with unmodified bentonite, which is attributed to the increasing in the ability of adhesion between the filler and pvc matrix. 7. the results showed a significant improvement on the values of hardness for the different content of reinforcements. the highest hardness value was found in the case of organoclay content. 8. increase in impact strength was noticed in all fillers, when compared with the neat pvc for which the value of the impact strength is 4.57 kj/m 2 . this may be due to the bearing the major part of the impact energy by the filler. the 12% content of the organoclay showed the best impact strength value. 9. the results showed tg shifted toward higher temperature for all type of filler compared to neat pvc. also, thermal conductivity measured values illustrated that pvc/bentonite composites have a good thermal insulation at 12wt%. thermal conductivity was decreased from 0.222 w/m. k for neat pvc to 0.11 w/m. k at 12wt% pvc/bentonite composites. the thermal insulation of the product is improved with a ratio of 50.4%. 10. the higher the filler content the higher burning time, the lower rate of burning and the lower height of the flame which are evident at 12wt% for all fillers. it was found that the best content of the organoclay is 12wt% added to the pvc. 11. there are general increases in absorption rate with increase in bentonite content. this behavior might be due to the presence of void spaces in the matrix which could have been formed during compounding of composites. the void space in the matrix accommodates the water absorbed, so the organoclay give the best possible absorbability of the pvc. with other word making it moisture resistant. abbreviations impact strength kj fraction energy cross-sectional area j/g. k specific heat capacity g / cm 3 density of sample references 1. turu, e.m., kolawole, e. g., gimba, c. e., dallatu, y.a. and yerima y., "effect of fired clay on the physical and mechanical properties of un-plasticized poly (vinyl chloride) composite", the international journal of engineering and science (ijes), vol. 3, pp. 2028, (2014). 2. hashim, f.s., "enhancement of mechanical properties for reinforced iraqi bentonite clay polyvinyl chloride composite using ultrasonic technique", chemistry and materials research, no. 6, vol. 2, pp. 24–32, (2012). 3. a.m. motawie, a.a.khalil, a.i.a. eid, k.m. el-ashry, e.m.s., "some studies on poly (vinyl chloride)/layered silicate nanocomposites part 1, morphology, physico-mechanical, and thermal properties", journal of applied sciences research,no. 12, vol. 9, pp. 6355–6364, (2014). 4. savrik, s. a., b. c. erdogan, d. balkose and s.ulku, "statistical thermal stability of pvc", journal of applied polymer science, no. 3, vol. 116, pp. 1811-1822, (2010). 5. yalcin, b. & cakmak, m., " the role of plasticizer on the exfoliation and dispersion and fracture behavior of http://www.iasj.net/ preparations of organoclay using cationic surfactant and characterization of pvc/ (bentonite and organoclay) composite prepared via melt blending method 34 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net clay particles in pvc matrix: a comprehensive morphological study", polymer, no. 19, vol. 45, pp. 6623–6638, (2004). 6. yun-hwei, s., "preparations of organobentonite using nonionic surfactants, journal of chemosphere, vol. 44, pp. 989-995, (2001). 7. mousavi, s. m., alemzadeh, i. and vossoughi, m., "use of modified bentonite for phenolic adsorption in treatment of olive oil mill waste water", iranian journal of science & technology, transaction b, engineering, vol. 30, b5, (2006). 8. zhou, q., he, h., frost, r. l. and xi, y., "organoclays prepared from montmorillonites with different cation exchange capacity and surfactant configuration", j. phys. chem., vol. 111, pp. 7487-7493, (2007). 9. ismail, h. & munusamy, y., "polyvinyl chloride/organoclay nanocomposites: effects of filler loading and maleic anhydride", journal of reinforced plastics and composites, no. 16, vol. 26, pp.1681–1694, (2007). 10. karakus, s., budinski-simendic, j., korugic-karasz, l. and z. aroguz, a., " characterization of poly ( vinyl chloride)/ bentonite nanocomposite prepared via melt blending method", in: ljiljana korugic-karasz. ed. contemporary science of polymeric materials. washington, dc: american chemical society .chapter 8, pp 103-113, (2010). 11. wang, s., hu, y., wang, z., yong, t., chen, z. and fan, w., "synthesis and characterization of polycarbonate/abs/montmorillonite nanocomposites", polymer degradation and stability, no. 1, vol. 80, pp.157–161, (2003). 12. shelley, j.s., mather, p.t. & devries, k.l., "reinforcement and environmental degradation of nylon-6 / clay nanocomposites", polymer, vol. 42, pp. 5849–5858, (2001). 13. lagaly, g., "clay organic reactions", interactions. philosophical transactions .royal soc., london, england, (1984). 14. alther, g. r. , "removing oils from water with organoclays", american water works association journal, no. 7, vol. 94, pp. 115 121, (2002). 15. ko, m. b., "effects of acrylonitrile content on the properties of clay-dispersed poly (styreneco-acrylonitrile) copolymer nanocomposite", polymer. bull., vol. 45, pp. 183–90, (2000). 16. alther, g. r., evans, j. c. and pancoski, s. e., "organically modified clays for stabilization of organic hazardous waste", hmcir’s 9th national conference, superfund 88, silver spring, pp.440445, (1988). 17. wilkes, c.e., summers, j.w., daniels, c.a. and bernard, m.t., "pvc handbook", hanser verlag, pp. 176-181, (2005). 18. pasdar, m.d. and h., "the influence of a variety of plasticisers on properties of poly ( vinyl chloride )", pelagia research library advances in applied science research, no. 4, vol. 3, pp.1900–1904, (2012). 19. xu, w., ge, m. & pan, w., "glass poly vinyl chloride/ montmorillonite nanocomposites transition temperature and mechanical properties", journal of thermal analysis and calorimetry, vol. 78, pp. 1–9, (2004). 20. zadeh, a. j., sarrafi, a., rahimi, m. z. and soltaninejad, s., "processing polyethylene/clay http://www.iasj.net/ basma a. abdul majeed and dhilal amer sabar -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 35 nanocomposites from bentonite prepared from persian clay", chemical engineering, pp. 1–5, (2011). 21. sulaymon, p.a.h. & kshash, j.m., "removal of oil from wastewater by organoclay prepared from iraqi bentonite", journal of engineering, no. 4, vol. 16, pp. 5778–5798, (2010). 22. frost, r., carmody, o., xi, y. and kokot, s., "adsorption of hydrocarbons on organo-clays implications for oil spill remediation", journal of colloid and interface science, no. 1, vol. 305, pp. 17-24, (2007). 23. bonadies, i., avella, m., avolio, r., carfagna, c., errico, m. and gentile, g., "poly (vinyl chloride)/caco3 nanocomposites: influence of surface treatments on the properties", journal of applied polymer science, no. 6, vol. 122, pp.3590-3598, (2011). 24. deshmukh, s.p. & rao, a c., "mica filled pvc composites : performance enhancement in dielectric and mechanical properties with treated / untreated mica of different particle size and different concentration", no. 2, vol. 11, pp.169–181, (2012). 25. mateusz b., "carbon nan tube networks in epoxy composites and aero gels", phd. thesis, university of pennsylvania, (2007). 26. selvaraj, d. edison, "partial discharge characteristics of enamel filled with micro and no composite of sio2 and tio2", international journal of science and engineering applications 1.2, pp. 95-101, (2012). 27. fadhil, k. f., "empirical and simulation investigations of tribological and thermal characteristics of polymer nano composites", phd. thesis, science of college, al-mustansiriyah university, (2015). 28. gonzaga, a. c., sousa, b. v., santana, l.n.l., neves, g. a. and rodrigues,m.g.f., "study of different methods in the preparation of organoclays from the bentonite with application in the petroleum industry", brazilian journal of petroleum and gas, no. 1, vol. 1, pp.16-25, (2007). 29. wisam h. hoidy, mansor b. ahmad, emad a. jaffar al mulla and norazowa bt ibrahim, "synthesis and characterization of organoclay from sodium montmorillonite and fatty hydroxamic acids", american journal of applied sciences, no. 8, vol. 6, pp. 1567-1572, (2009). 30. valenzuela diaz fr., "preparation of organophilic clays from a brazilian smectitic clay", key engineering materials, no. 191, vol. 189, pp. 203-7, (2001). 31. caroline, b., ana lucia, p. d. a. and sirlei, j. k., "evaluation of brazilian organoclay synthesized in the laboratory and commercial", chemical engineering transactions, vol. 24, pp. 1537-1542, (2011). 32. bhattacharya, s.s. & aadhar, m., "studies on preparation and analysis of organoclay nano particles", research journal of engineering science, no. 3, vol. 3, pp.10–16, (2014). 33. bertagnolli, c., silva, m.g.c.d., "characterization of brazilian bentonite organoclays as sorbents of petroleum-derived fuels", materials research, no. 2, vol. 15, pp. 253-259, (2012). 34. bala, p., samantary, b. k. and sirvastava, s. k., "synthesis and characterization of namontmorillonite alkylammonium intercalation compounds", http://www.iasj.net/ preparations of organoclay using cationic surfactant and characterization of pvc/ (bentonite and organoclay) composite prepared via melt blending method 36 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net materials research bulletin, vol. 35, pp. 1717-1724, (2000). 35. charles j, pouchert, "the aldrich library of infrared spectra", third edition, new york, (1983). 36. pereira, k.r.d.o.p., hanna, r.a., vianna, m.m.g.r., pinto, c.a., rodrigues, m.g.f. and valenzuela-diaz, f.r., "brazilian organoclays as, nanostructured sorbents of petroleum-derived hydrocarbons", materials research, no. 1, vol. 8, (2005). 37. nahida, j. h., & ali, z. m., "astudy of the effect of silica particles addition on some physical properties of pvc as a packaging material, iraqi journal of physics, no.26, vol. 13, pp. 76-91, (2015). 38. hai liu, lijie dong, haian xie and chuanxi xiong, "novelmodified kaolin for enhancing the mechanical and thermal properties of poly (vinyl chloride), polymer engineering and science, no. 10, vol. 52, (2012). 39. n. jon, i. abdullah, and r. othaman, sains malaysiana, no. 4, vol. 24, pp. 469-474, (2013). 40. shimpi, n.g. and s. mishra, "studies on effect of improved dspacing of montmorillonite on properties of poly (vinyl chloride) nanocomposites", journal of applied polymer science, no. 1, vol. 119, pp. 148, (2011). 41. mcnally t., halley p., murphy m. and martin d., polymer, vol. 46, pp. 8222, (2005). 42. khalil, m.r., "enhancement of mechanical and thermal properties for iraqi bentonite clay polyring", m. sc. thesis, babil university, (2013). 43. faris a.h., "study the effect of using some inorganic and halogenated additives for the flame retardant additives and increase the fire resistance of epoxy resin", m.sc. thesis, alrashed college, technology university, (2003). 44. beyer g., "organoclays as flame retardants for pvc", polymers for advanced technologies, vol. 19, pp. 485–488, (2008). http://www.iasj.net/ iraqi journal of chemical and petroleum engineering vol.17 no.2 (june 2016) 7986 issn: 1997-4884 determination of the optimum conditions for the production of gamma alumina (ɤ-al2o3) by the precipitation method of the sodium aluminate solution alaa d. jawad al-bayati * , habaib a. majeed al-taee * and ibtehaj faisal abdulraheem ** * department of chemical industries, institute of technology baghdad, middle technology university, iraq ** department of chemical engineering, college of engineering, university of baghdad, iraq abstract design of experiments (doe) was made by minitab software for the study of three factors used in the precipitation process of the sodium aluminate solution prepared from digestion of α-al2o3 to determine the optimum conditions to a produce boehmite which is used in production of ɤ-al2o3 during drying and calcination processes, the factors are; the temperature of the sodium aluminate solution, concentration of hcl acid added for the precipitation and the ph of the solution at which the precipitation was ended. the design of the experiments leads to 18 experiments. the results show that the optimum conditions for the precipitation of the sodium aluminate solution which leads to the production of gamma alumina are 6.5 ph, temperature of solution is 90 c and the concentration of the hydrochloric acid (hcl) is 21%. while all other conditions lead mainly to other phases of alumina which is mainly epsilonalumina (ε-al2o3). key words: gamma alumina, precipitation, xrd introduction boehmite is the starting material for the production of gamma alumina by precipitation method [1]. precipitation is one of the important steps used in the production of alumina by bayer process. in the precipitation process the kinetics of the precipitation is very slow which need huge tanks for precipitation the liquor of diluted alumina. large flow rate means the need of large residence time in the precipitation tanks i.e. large volume tanks [2, 3]. precipitation of boehmite (al2o3.h2o) instead of gibbsite (al2o3.3h2o) in the process of alumina production is an energy saving [4]. . gamma alumina is one of the important materials used in industry as adsorbents, catalyst supports and catalysts in the form of nano powder or as thin film coatings and in because it has large specific area, low cost, good thermal properties, surface acidity and interaction with deposed transition metals [5-11]. ɤ-al2o3 is used in the production of boehmite by either the precipitation or iraqi journal of chemical and petroleum engineering university of baghdad college of engineering determination of the optimum conditions for the production of gamma alumina (ɤ-al2o3) by the precipitation method of the sodium aluminate solution 80 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net hydrothermal methods needs to control the aluminum source, ph, temperature of the precipitation from the alumina liquor, aging, and the drying conditions and others affect the crystalline shape and size of the boehmite product [12]. the precipitation step in bayer process needs 48-72 h and it is he limiting step in the production of alumina by bayer process and precipitation method [13]. the method of precipitation, drying and calcination is one of the important methods of producing alumina from aluminium oxy-hydroxides [14]. all the stages used in the synthesis of aluminium hydroxides such as the solution ph, the concentration of the aluminium hydroxide in the liquor, temperature and many others has important effect on the properties of alumina produced [15]. aluminium hydroxide is normally produced by the hydrolysis of the aluminium salts, alcoholates and from metallic aluminium. there are methods of precipitation the alumina from the salts by using ammonia treatment [16-18] and by precipitation with acid treatment [19]. experimental procedure sodium aluminate solution was prepared by digestion of 80 grams αal2o3 powder with one liter 3.5 m sodium hydroxide solution in 2 liter volume autoclave, the temperature for digestion is 190 c , absolute pressure 11.5 bar and the time for digestion is 3 hours. design of experiments (doe) was made by mini tab statistical software to study 3 factors affecting the precipitation of alumina from sodium aluminate solution by acid addition which is; ph at which ending the addition of the acid, temperature of precipitation solution and concentration of the hcl acid added. the range of each factor is as shown in table (1). table (2) shows the conditions of the 18 experiments obtained in the doe. 50 ml of sodium aluminate solution is taken as a base for executing the acid precipitation for each experiment in the above doe, the ph is tested by ts 625 ph meter, the temperature was regulated by magnetic stirrer heater and measured by mercury thermometer. the precipitate was filtered by 5 micron filter paper to separate the precipitate from the mother liquid and then washed several times with distilled water to remove all the contaminates and nacl salt. table 1, range of the factors studied serial factor minimum maximum 1 ph 6 9 2 temperature o c 80 100 3 hcl% 5 37 table 2, conditions of the experiments of doe run name of precipitate sample ph temp. o c hcl% 1 pdf-1 7 80 21 2 pdf-2 7 90 21 3 pdf-3 8 84 11.5 4 pdf-4 7 90 21 5 pdf-5 6.5 96 11.5 6 pdf-6 7 90 37 7 pdf-7 8 96 11.5 8 pdf-8 8 96 30.5 9 pdf-9 6 84 30.5 10 pdf-10 6 96 30.5 11 pdf-11 7 90 21 12 pdf-12 8 84 30.5 13 pdf-13 6.5 90 21 14 pdf-14 7 100 21 15 pdf-15 7 90 5 16 pdf-16 8 90 21 17 pdf-17 7 90 21 18 pdf-18 7 90 21 alaa d. jawad al-bayati, habaib a. majeed al-taee and ibtehaj faisal abdulraheem -available online at: www.iasj.net ijcpe vol.17 no.2 (june 2016) 81 the precipitate was dried at 120 c for 4 hours in memmert oven, and then calcined at 550 c in a furnace with a calcination program as shown in table (3). the calcination program was chosen according to our experience and literature [20-21] xrd tests were made to all the calcined precipitates by xrd instrument using cukα at 40 kv and 30 ma. table 3, calcination program for alumina production from sodium alumina acid precipitation serial temperature 0 c time minutes 1 200 60 2 280 45 3 300 5 4 325 5 5 350 5 6 375 5 7 400 5 8 425 5 9 450 5 10 475 5 11 500 5 12 525 5 13 550 150 total time for calcination 5 hr. +5 min. table (4) show the maximum three peaks for each of the alumina and the phase obtained from the doe we made. table (5) show the maximum three peaks of the alumina phases [22]. table 4, the strongest 3 xrd peaks (2θ) and type of alumina phase obtained in each experiment of the doe. no. precipit ate name 2θ for the strongest 3 xrd peaks alumina phase 1 pdf-1 45.937,46.51,36.95 epsilon ε 2 pdf-2 45.937,46.51,36.95 epsilon ε 3 pdf-3 45.937,46.51,36.95 epsilon ε 4 pdf-4 45.937,46.51,36.95 epsilon ε 5 pdf-5 45.937,46.51,36.95 epsilon ε 6 pdf-6 45.937,46.51,36.95 epsilon ε 7 pdf-7 45.937,46.51,36.95 epsilon ε 8 pdf-8 45.937,46.51,36.95 epsilon ε 9 pdf-9 45.937,46.51,36.95 epsilon ε 10 pdf-10 45.937,46.51,36.95 epsilon ε 11 pdf-11 45.937,46.51,36.95 epsilon ε 12 pdf-12 45.937,46.51,36.95 epsilon ε 13 pdf-13 pdfg13-d 66.76,23.44,37.68 48.87,28.03,38.40 ϫ-alumina boehmite 14 pdf-14 45.937,46.51,36.95 epsilon ε 15 pdf-15 45.937,46.51,36.95 epsilon ε 16 pdf-16 45.937,46.51,36.95 epsilon ε 17 pdf-17 45.937,46.51,36.95 epsilon ε 18 pdf-18 45.937,46.51,36.95 epsilon ε table 5, 2θ for the strongest 3 xrd peaks of some standard alumina phases [22] alumina phase d-spacing for the strongest 3 xrd peaks 2θ epsilon ε 1.979,1.947,2.451 45.81,46.61,36.63 gamma 1.4,1.98,2.39 66.76,45.78,37.60 alpha 2.08,2.55,3.479 43.36,35.13,25.58 results and discussions figures 1-19 show the xrd peaks for the calcined samples obtained in our acid precipitation study of the sodium aluminate solution to produce ɤ-al2o3. it is noticed that the conditions of 6.5 ph, 90 0 c temperature and 21% hcl acid concentration leaded to production of boehmite after drying (4 hours @ 110 0c and 1 hr. @200 0 c and 45 minutes @ 280 0 c) determination of the optimum conditions for the production of gamma alumina (ɤ-al2o3) by the precipitation method of the sodium aluminate solution 82 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net fig. 1, xrd for pdf-1 fig. 2, xrd for pdf-2 fig. 3, xrd for pdf-3 fig. 4, xrd for pdf-4 fig. 5, xrd for pdf-5 fig. 6, xrd for pdf-6 alaa d. jawad al-bayati, habaib a. majeed al-taee and ibtehaj faisal abdulraheem -available online at: www.iasj.net ijcpe vol.17 no.2 (june 2016) 83 fig. 7, xrd for pdf-7 fig. 8, xrd for pdf-8 fig. 9, xrd for pdf-9 fig. 10, xrd for pdf-10 fig. 11, xrd for pdf-11 fig. 12, xrd for pdf-12 determination of the optimum conditions for the production of gamma alumina (ɤ-al2o3) by the precipitation method of the sodium aluminate solution 84 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net fig. 13, xrd for pdf-13 fig. 14, xrd for pdf-14 fig. 15, xrd for pdf-15 fig. 16, xrd for pdf-16 fig. 17, xrd for pdf-17 fig. 18, xrd for pdf-18 alaa d. jawad al-bayati, habaib a. majeed al-taee and ibtehaj faisal abdulraheem -available online at: www.iasj.net ijcpe vol.17 no.2 (june 2016) 85 fig. 19, xrd for boehmite obtained from pdf-13 precipitation conditions and drying (4 hours @ 110 0 c and 1 hr. @200 0 c and 45 minutes @ 280 0 c) conclusion 1this work confirmed that the optimum conditions which lead to gamma alumina is very critical and need to be precise to precipitate boehmite and then to produce gamma alumina. 2as shown in figure 13, the optimum conditions of ph 6.5, temperature 90 0 c and the hcl concentration is 21%. leads to boehmite during precipitation 3the digestion of α-al2o3 with 3.5 m sodium hydroxide solution in autoclave at temperature of 190 0 c, 11.5 bar absolute pressure and 3 hours the time for digestion was succeeded in conversion α-al2o3 to ɤ-al2o3 and it is compatible with the well-known literature of chemistry of bayer process. 4the doe results shows that the interaction effects between the factors studied during precipitation is very important, and even any one or two factors are the same, the type of the alumina precipitated is different. 5the use of α-al2o3 as a source for producing ɤ-al2o3 is promising in the production of boehmite and gamma alumina. acknowledgments the research was funded by the chemical industries department in institute of technology baghdad. additional support for this study was received from the central laboratories of the iraq geological survey committee. references 1r. tipakontitikul, a. niyompan, k. srisurat, n. kanchanarat, t. tunkasiri, journal of micros copy society of thailand 22 , 20-22 (2008). 2barsha dash, b.c.tripathy, i.n.bhattacharya and b.k.mishra, the royal society of chemistry, daltontrans., 39, 9108–9111(2010). 3parida, k.m, pradhan, a. maresh c., das, j and sahu nrup,"synthesis and characterization of nano-sized porous gamma alumina by controlled precipitation method", materials chemistry and physics, 113(2009)244-248. 4http://www.alteoalumina.com/en/cal cined-aluminas. 5kotanigawa, t, yamamoto, m.,utiyama,m., hattori, h. tanabe, k., j. applied catalysis , ,1(7), 185200 (1981). 6beguin b., garbowski e., primet m., j. of catalysis, ,127(2), 595-604 (1991). 7peng x s. zhang l.d, meng g. w., j. phys chem b, 106(43), 1116311167 (2006). 8lee h. c. ,kim h. j. ,chung s. h., j. am chem soc, 125(10), 28822883 (2003). 9k.a. de friend, m.r. wiesner, a.r. baron, j. membr sci. vol. 224, 11-28 (2003). http://www.alteoalumina.com/en/calcined-aluminas http://www.alteoalumina.com/en/calcined-aluminas determination of the optimum conditions for the production of gamma alumina (ɤ-al2o3) by the precipitation method of the sodium aluminate solution 86 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net 10y. cho, k. han, k. lee, ,j. membr sci. 104, 219 (1995). 11x. changrong, w. feng, m. zhaojing, l. fanqing , p. dingkun, m. guangyao, j. membr sci. 116, 9-16 (1996). 12petrovice, r., miynlonjic, s., jokanovic, v., kosticgvozdenovic, lj., petrovicprelevic, i., and janackovic, dj. , powder technology, 133, 185-189 (2003). 13chen, g.h., chen, q.y., yin, zl. zhang,b., human metallurgy ,31(1), 3-6 2003. 14bokhimi x., sanchez-valente j., pedraza f., journal of solid state chemistry, 166(1), 182-190 (2002). 15v.a. dzisko, a.s. ivanova, and g.l. vishnyakova, kinetika i kataliz,11, 483 (1970) 16s. music, d. dragcevic, s. popovic, and n. vdovic, mater. chem. phys., 59, 12 (1999) 17v.k. singh and r.k. shina, mater. lett., 18, 201(1994) 18n. idrissi-kandri, a. ayral , ch. guizard, et al., mater. lett, 400, 52 (1999) 19g.l. vishnyakova, v.a. dzisko, l.m. kefeli et al., kinetika i kataliz, 11, 1541 (1970) 20al-bayati, alaa d. j, phd thesis,"manufacturing and description of platinum alumina used in reforming units of petroleum refineries' 2011, syria. al-baath university. 21hlavac, j. ' the technology of glass and ceramics an introduction', 4 th edition, elsevier scientific publishing company, new york, 1983. 222015 international center for diffraction data. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol. 24 no.1 (march 2023) 33 – 39 eissn: 2618-0707, pissn: 1997-4884 *corresponding author: name: herish bibani, email: hairash.nadhum1308d@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. cold cracking technology for crude oil upgrading in qaiyarah heavy oil field; technical and economical evaluation herish bibani a, *, ayad a. alhaleem a, and mohammad sharifi b a petroleum engineering department, college of engineering, university of baghdad, baghdad, iraq b amirkabir university of technology, petroleum engineering department, iran abstract heavy oil is classified as unconventional oil resource because of its difficulty to recover in its natural state, difficulties in transport and difficulties in marketing it. upgrading solution to the heavy oil has positive impact technically and economically specially when it will be a competitive with conventional oils from the marketing prospective. developing qaiyarah heavy oil field was neglected in the last five decades, the main reason was due to the low quality of the crude oil resulted in the high viscosity and density of the crude oil in the field which was and still a major challenge putting them on the major stream line of production in iraq. the low quality of the crude properties led to lower oil prices in the global markets as well as the high operation cost of production and transportation. the purpose of this paper is testing new technology applications on an iraqi heavy oil field and specifically (qaiyarah oil field) by applying the cold cracking technique to upgrade qaiyarah heavy oil properties through using series of electrical/ mechanical activities applied on the heavy crude that generates special kind of vibrations to re-structure the (h-c) bonds in the heavy oil to convert it to lighter crude with lower viscosity/ density which was the outcome of the distillation by reducing the unsaturated components and isolating the minerals and sulfur as sold components. the results were very optimistic, where the density has improved from 16 to 30.5 api degree, sulfur content has reduced from 6.4 to 1.507 weight percent and selling price per barrel would increase by 53% compare to 2.31% cost increment due to the upgrading operation. therefore, applying the cold cracking technology is convenience for improving qaiyarah oil properties as the main production stream line will be increased in iraq. keywords: cold cracking; qaiyarah heavy oil field; heavy crude upgrading; synthetic oil; oil production cost. received on 26/07/2022, received in revised form on 27/08/2022, accepted on 31/08/2022, published on 30/03/2023 https://doi.org/10.31699/ijcpe.2023.1.5 1introduction it is crucial to study the heavy crude properties which is influenced by its heavy components [1]. most of the major oil companies started looking for developing and resolving challenges of heavy oil fields in the world through studying subsurface, production operations and transportation to marketing, more specifically to develop the heavy oil industry globally, especially when considering that the unconventional crudes are making around 70% of the world hydrocarbon reserves [2]. as, the production from of high quality (light) crude oil is approaching its peak, more attention is has shifted in the petroleum industry is directed toward the development of a large quantity of heavy oil and bitumen to ensure sustainable supply to the growing demand for energy. these low quality hydrocarbons (heavy oil and bitumen) are usually known by high viscosity, low api gravity and high density [3]. there are great unconventional oil beds in canada, venezuela and middle east that reach a total amount around 5 to 7 trillion barrels, with recovery potential in the order of 800 billion barrels, which could assist, satisfactorily, the future derivate needs for world consumption. however, the athabasca oils (canada) and the bosman oils (venezuela) contain a high sulfur content 4.27 and 5.27% in mass [4]. by increasing the cost of producing the heavy crudes compare with the conventional oil, developing and getting the conventional crudes started to reduce due to the extra production for compensating the global markets, especially when oil prices reached more than $100 per barrel. at that time the oil companies started to focus on heavy oil production again in a try to satisfy the demand markets for crude oil [5]. this action, put the initiation steps to be one of the major sources of blending crudes in the early future. additives like naphtha is reducing the high viscosity while is blended with heavy oil [6], but usually there will be some sort of instability after the mixing process resulted in different kinds of undesired residuals. the viscosity of heavy oil is diminishing with increasing solvent concentration [7]. heavy and extra heavy crude production and treatment issues started to be one of the most cortical matter in the oil industry of iraq, since this type of crudes have a noticeable portion of iraq oil reserves and the expectations that the conventional crude production will eventually drop and at that time to maintain the production plateau needs to develop the heavy crude fields which have a major challenge that is http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:hairash.nadhum1308d@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2023.1.5 h. bibani et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 33 39 34 the transportation to the export points since heavy oil transportation has become a complex and highly technical operation especially when it contains sulphur [8]. qaiyarah oil field have been discovered by the german in 1918 by the appearance of the seepages at the surface, where the major portion of the field is located to the west of tigress river about 65 km southern of the city of mosul, fig. 1 [9]. the field dimension is about 15 km length and 3.5 km width. qaiyarah field is an anticline trap forming part of a bigger structure composed of 4 anticlines: qaiyarah, najmah, jawan, and qasab. the three first structures are successive individual, culminations on a single fold axis, which trends approximately northwest from the western bank of the tigris at qaiyarah. qasab is a parallel anticline, with two domes, which is offset to the northeast, and separated from jawan by a broad, shallow synclinal saddle, fig. 2 [9]. s fig. 1. qaiyarah field location [9] fig. 2. qaiyarah field reservoir structure [9] because of the low quality properties of qaiyarah crude oil, the production was limited only to a local refinery since 1970s. the main aim of this paper is having technical and economical evaluation of this field using the latest techniques for heavy crude upgrading in a tray to upgrade the heavy crude of qaiyarah oil field. result of this study can be considered as an initiation step to continue developing other four fields in the region which have almost the same crude oil properties as shown in table 1 mentioning the volume of available crude in the region in order to produce a synthetic crude that can compete the conventional crudes in north of iraq. fig. 3 shows a group of fields on the same trend line having the same properties. table 1. available crude in qaiyarah and other field in the same region [9] field qaiyarah najmah qasab jawan stiiop (mmstb) 6,856 5,718 2,318 6,716 reserve (mmstb) 813 858 347 1007 api 16 17 17 17 sulfur content (wt.%) 7.3 7.6 6.7 6 fig. 3. group of heavy oil fields in north of iraq [10] 2methodology there is an important point related to producing unconventional crudes indicating besides the cost of production, there will be another issue of transportation cost, this is all because of its high viscosity/density so, its prices will be much lower than the conventional crudes. by applying new technology of upgrading the properties of qaiyarah heavy oil through applications of cold cracking technology to upgrade the crude properties to be a competitive for the conventional crudes and making a technical comparison analysis of the crude properties as well as economical evaluation of the crude prices before and after the upgrading that is going to be an encouragement push to develop many other fields in the region. this paper will evaluate results of crude analysis taken from qaiyarah oil field in north of iraq before upgrading and after applying the upgrading to enhance the crude properties specifically density, viscosity and sulfur content which are considered as a major property that are effecting on the quality of crudes and eventually its prices. after completing the production operations, the major challenge facing qaiyarah crude is the transportation to the refineries or the export points and since there is no independent flow lines to transport the heavy crude h. bibani et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 33 39 35 separately, the only options was available is to mix the heavy crude with conventional crudes of the northern fields in north of iraq which have average api of 32, but this was causing a depositions in the flow lines leading to block the flow in the pipe lines and on the other hand reducing the quality of the selling crudes and this was unfeasible and not acceptable by iraqi oil ministry. there is a possibility to take advantage from previous experiences of heavy crude upgrading that are used in canada and venezuela since there are consider top pioneer countries in producing and upgrading heavy and extra heavy crudes. a feasibility study has been done showing a comparative of operating expenditure (opex) and barrel price before and after the upgrading using eqs. 1 and 2 [3]. price of qaiyarah heavy crude without upgrading = brent mixture − $32 (1) synthetic crude with upgrading = brent mixture + $5 (2) 2.1. possibility of upgrading qaiyarah heavy crude qaiyarah field stiiop is around 6.856 mmm stb and the reserve is estimated to be 813 mmstb by primary production mechanism. due to the high sulfur content and hydrogen sulfide reduced the options of selecting an optimum technique to upgrade the heavy crude properties without considering the huge volumes of produce sulfur. table 2 and table 3 represents qaiyarah heavy crude oil composition and properties for the treated and untreated oil, respectively. table 2. qaiyara crude /reservoir fluid analysis (treated)1 [9] composition weight percentage (wt.%) c1 0.22 c2 0.70 co2 0.07 2h2s 0.91 c3 0.89 ic4 0.24 nc4 0.92 ic5 0.78 nc5 0.63 c6+ 94.64 sp.gr. for c6+ measured at 60/60 °f 0.9830 sp. gr. of the reservoir fluid measured at 60/60 °f 0.9444 measured gor (scf/stb) 104 1 average analysis from two key wells. 2 this value is relatively low, could be due to observing the hydrogen sulfide by the minerals of the container. table 3. qaiyara crude /reservoir fluid analysis (untreated)1 [9] property measured value api gravity 15.6 kinematic viscosity at 80°f (c st) 489 h2s (ppm) 1200 sulfur (wt %) 7.6 asphaltine (wt %) 12.2 wax (wt %) 2.0 1 average analysis from two key wells. based on the field development plan, there will a possibility to increase the production plateau to reach 130,000 bbl/day and this is considering a huge step in developing the field and based on that, upgrading the crude oil properties to be comparative to the conventional iraqi crudes using latest upgrading processes to make qaiyarah synthetic crude. the next section will be the use of new technology in upgrading, which is improving qaiyarah crude properties and make an optimum technical/ feasible evaluation. 2.2. cold cracking technology cracking disrupts hydrocarbons into simpler molecules for upgrading the heavy crude oil quality [11]. fig. 4 is showing a schematic diagram of the upgrading of heavy oil through the bond breakage in the asphaltene [12, 13]. fig. 4. schematic diagram of upgrading of heavy oil through bond breakage [12] heavy crude oil eventually will be used to meet the growing demand for fuels since most if not all of the world's refineries are not suitable for processing these types crude, so upgrading processes are required to make synthetic crude oils from those resources compatible with the equipment installed [16]. the cold cracking technique consider a huge jump in the upgrading process by avoiding using chemical or thermal materials, also proving synthetic crudes with very high quality properties compare to the other traditional methods as shown in fig. 5. fig. 5. cold cracking unit and hydrogen extractor unit [12] h. bibani et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 33 39 36 in general, the conversion process is proposed to reduce the production of heavier components [13]. the idea behind this technique is a series of electrical/mechanical activities applied on the heavy crude that generates special type of vibrations to re-structure the (h-c) bonds in the heavy oil to convert it to lighter crude with lower viscosity and density [12,15]. this technique will apply a vibration electron that cause rearrange the electrons of hydrogen – carbon and cause changing the physical and chemical properties for the atoms and this could be summarized below: • unstable the hydrogen electrons. • break down the (c c) single and double bonds at the same time the (h – c) bonds to convert the heavy component to medium distillation products. • reconstruct the treated (h – c) bonds which was the outcome of the distillation by reducing the unsaturated components. • isolate the minerals and sulfur as sold components. this technique worked efficiently on qaiyarah crude by separating the hydrogen sulfide which is one of the major challenges in producing the heavy oil in the area, and took the hydrogen atoms to separate the sulfur as solid material. fig. 6 is representing mechanism how the system can be working in qaiyarah, since there is a refinery next to the field. fig. 6. flow chart showing how the system will be working in qaiyarah 3results and discussion sample of crude oil has been taken from qaiyarah field / south degassing station to the central laboratories at north oil company in kirkuk/iraq for complete analysis and normal inspection data (nid). similarly, another sample from same mentioned source was analyzed after apply the cold cracking technology on it. the results of crude oil analysis before and after the upgrading process is shown in table 4. it can be notice clearly that most the crude oil properties which is evolve to make the crude oil being heavy are upgraded positively and be competitive to the conventional crude oils. at the same time and as it can be seen from fig. 7, the analysis results, there is a noticeable increment in the api of the synthetic crude with huge decreasing in the viscosity and the sulphur content. table 5 shows the cost per barrel of qaiyarah crude before and after applying any upgrading and price of selling crude as it was announced by iraqi government through the selling oil marketing company (somo), ministry of oil (moo/iraq) on jul./2022, where the selling price for qaiyarah oil was 50.4 $/bbl of and average selling price for the conventional oil from other oil fields of iraq was 92.6 $/bbl at the export point in jihan perl in turkey, while brent price was 118 $/bbl. table 4. crude oil analysis before and after the treatment parameter crude analysis before treatment crude analysis after treatment source qaiyarah / north degassing station cold cracking unit outlet sampling date feb.-2019 mar.-2019 sp.gr ( 60/60 f° ) 0.959 0.876 api 15.9 30.5 water content (%vol.) 5.4 6 h2s (ppm) 659 110 bs & w% vol. by centrifuge 6 6 salt (ppm) 7.25 7.25 acid number (mg koh/g) 1.63 1.63 organic chloride (ppm) 4.6 4.55 sulphur ,%wt 7.6 1.507 kinematic viscosity at (80 f° ) (cst) 489 15.679 table 5. qaiyarah crude activity cost/ bbl before and after upgrading analyzing the results of the treatment technically and comparing the prices over all showed encouraging results to go further with this technology through applying it on the heavy oil field in iraq. after upgrading the crude to reach 31 in api gravity which is almost close to the selling mixture of north of iraq crudes that was around 32 api gravity. by that, the profit percentage from single barrel will increase around 53% in a comparative of opex increment by almost 2.31 $/bbl. the feasible study can be summarized through as a comparison between the synthetic crude which is upgraded and actual qaiyarah heavy crude that was with api gravity ranging 16 – 20 taking into account the two equations that mentioned earlier as average of selling price of heavy crude and synthetic crude as it is also shown in fig. 8. although there are some uncertainties in oil price and other practical issues in cold cracking technology but looking at fig. 8, it can be seen that using this technology can lead to huge economic benefit. more detailed feasibility analysis can be conducted to consider all practical issues and reduce the uncertainties. gas treatment sulfur removal heavy crude s y n t h e t i c c r u d e 90% of c-s bonds are cracked and seperated h-c and c-c cracking converted to lighter sulfur export or refinary cold cracking unit activity/ bbl before upgrading after upgrading production cost 7.2 7.2 contractor cost 5 5 crude transportation by trucks 1 operating cost using the upgrading units 3 unit maintenance cost 0.31 total 13.2 15.51 h. bibani et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 33 39 37 fig. 7. results comparisons in qaiyarah properties before and after upgrading fig. 8. price comparison between qaiyarah heavy crude and synthetic (upgraded) crude, somo/ moo/iraq 4conclusions changing in physical and chemical composition of the heavy crude by applying cold cracking technology has a noticeable positive impact in making a synthetic crude and can be considered a competitor to the conventional crudes. qaiyarah crude oil have been upgraded from 16 to 30.5 api degree by taking advantage of increasing the hydrogen bonds to upgrade the crude quality by reducing the density and viscosity as well as the sulfur content and this will upgrade the crude quality and eventually the crude price as well as reducing the transportation problems. most important is, the possibility of mixing the synthetic crude with conventional crude from the other fields in the same region to be exported because of the convergence of the properties for the mixed crudes. based on that; it is highly recommended to go further with this technology’s application in the iraqi heavy oil field through installing a primary test unit for further future strategy to develop these fields and particularly qaiyara field. references [1] d. wang, l. jin, y. li. hu. upgrading of heavy oil with chemical looping partial oxidation. energy fuel, 2019, pp. 256 – 270. [2] li, d., the history and future of india oil and gas, 2005, https://doi.org/10.2523/iptc-10121-ms. [3] zhao, f. et al., a review on upgrading and viscosity reduction of heavy oil and bitumen by underground catalytic cracking 2021. energy reports, volume 7, pp. 4249—4272, https://doi.org/10.1016/j.egyr.2021.06.094. https://doi.org/10.2523/iptc-10121-ms https://doi.org/10.1016/j.egyr.2021.06.094 h. bibani et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 33 39 38 [4] rahnema, h., barrufet, m. & mamora, d. d., combustion assisted gravity drainage--experimental and simulation results of a promising in-situ combustion technology to recover extra-heavy oil., 2017. journal of petroleum science and engineering, volume 154, pp. 513—520, https://doi.org/10.1016/j.petrol.2017.01.044. [5] ibatullin, r., ibragimov,. n., khisamov, r. & zaripov, a. t., problems and solutions for shallow heavy oil production, 2012, https://doi.org/10.2118/161998-ms. [6] a. a. abdulrazak, m. al-khatieb, and h. a. faris, “problems of heavy oil transportation in pipelines and reduction of high viscosity”, ijcpe, vol. 16, no. 3, pp. 1–9, sep. 2015. [7] h. q. hussein and z. a. khedheer, “study the effect of using microwave radiation and h-donors on improving heavy oil”, ijcpe, vol. 18, no. 4, pp. 1– 13, dec. 2017. [8] h. qasim hussein and s. abdul-wahhab mohammad, “viscosity reduction of sharqi baghdad heavy crude oil using different polar hydrocarbons, oxygenated solvents”, ijcpe, vol. 15, no. 2, pp. 39– 48, jun. 2014. [9] ministry of oil – iraq. annual statistical report,2017. [10] a.a.m. aqrawi, j.c. goff, a.d. horbury and f.n. sadooni “the petroleum geology of iraq”, 2017. [11] john dwyer and david rawlence, “fluid catalytic cracking catalyst with heavy residual feedstocks”. volume 18, issue4, pages 487-507, december (1993), https://doi.org/10.1016/0920-5861(93)800659. [12] prestic company presentation., 2018., presented at ministry of oil/iraq. [13] ado, m. r., simulation study on the effect of reservoir bottom water on the performance of the thai in-situ combustion technology for heavy oil/tar sand upgrading and recovery., 2020., sn applied sciences, volume 2, pp. 1—16, https://doi.org/10.1007/s42452-019-1833-1. [14] m. ghashghaee, s. shirvani, s. kegnaes. steam catalytic cracking of fuel oil over a novel composite nano catalyst. j. anal. appl. pyrol. 138, 2019, pp. 280 – 294, https://doi.org/10.1016/j.jaap.2019.01.010. [15] jun long and deguang. zu., heavy oil upgrading with minimal investment cost research institute of petroleum processing, sinopec., 2020. [16] carrillo j.a., corredor l.m. upgrading of heavy crude oils: castilla. fuel process. technol., 109 (2013), pp. 156-162, https://doi.org/10.1016/j.fuproc.2012.09.059. https://doi.org/10.1016/j.petrol.2017.01.044 https://doi.org/10.2118/161998-ms https://www.iasj.net/iasj/download/bf1ee68094d58476 https://www.iasj.net/iasj/download/bf1ee68094d58476 https://www.iasj.net/iasj/download/bf1ee68094d58476 https://www.iasj.net/iasj/download/bf1ee68094d58476 https://www.iasj.net/iasj/download/47a343ee010eeecf https://www.iasj.net/iasj/download/47a343ee010eeecf https://www.iasj.net/iasj/download/47a343ee010eeecf https://www.iasj.net/iasj/download/47a343ee010eeecf https://www.iasj.net/iasj/download/60be931af6d05746 https://www.iasj.net/iasj/download/60be931af6d05746 https://www.iasj.net/iasj/download/60be931af6d05746 https://www.iasj.net/iasj/download/60be931af6d05746 https://www.iasj.net/iasj/download/60be931af6d05746 https://doi.org/10.1016/0920-5861(93)80065-9 https://doi.org/10.1016/0920-5861(93)80065-9 https://doi.org/10.1016/j.jaap.2019.01.010 https://doi.org/10.1016/j.fuproc.2012.09.059 h. bibani et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 33 39 39 نية فاسة تقنية التكسير البارد لتحسين مواصفات النفط الخام في حقل القيارة النفطي در وإقتصادية 2 ، ومحمد شريفي1 أياد عبد الحليم ،، *1 رش بيبانيهيرش ناظم حمه قسم هندسة النفط، كلية الهندسة، جامعة بغداد، بغداد، العراق 1 جامعة اميركبير للتكنولوجيا، قسم هندسة النفط، ايران 2 الخالصة يعية يصنف النفط الثقيل على انه مصدر نفطي غير تقليدي بسبب صعوبة استخراجه وانتاجه في حاالته الطب ية وصعوبة نقله وتسويقه. ان حلول تحسين مواصفات النفوط الثقيلة لها تأثيرات إيجابية من الناحية الفن . اهملباألخص من الناحية التسويقيةواإلقتصادية وباألخص عند وصولها الى مستوى تنافسي للنفوط التقليدية و ت هذا تطوير حقل القيارة النفطي في العقود الخمسة الماضية ويعود السبب الرئيسي في ذلك الى رداءة مواصفا من لحقل ضاالنفط من ناحية الكثافة واللزوجة العاليتين والتي كانت والزالت تمثل تحديًا كبيرًا في وضع انتاج لى ضافة اي العراق حيث ان أسعار النفط الثقيل تعتبر منخفضة جدا في األسواق العالمية إالمنظومة اإلنتاجية ف الكلف التشغيلية العالية من ناحية اإلنتاج والنقل. حديد حقل إن الهدف من هذه الدراسة هو اختبار تقنية جديدة على الحقول العراقية ذات النفوط الثقيلة وبالت سلسلة تطبيق تقنية التكسير البارد لتحسين مواصفات النفط الثقيل من خالل استخدام القيارة النفطي من خالل واصر كلية أمن الفعاليات كهربائية/ ميكانيكية تسلط على النفط الثقيل بتوليد نوع خاص من اإلهتزازات إلعادة هي ث ذات كثافة ولزوجة اقل، حييدروجين( في النفوط الثقيلة لتحويلها الى نفوط خفيفة او متوسطة ه-الـ )كاربون لـ درجة بمقياس معهد البترول األمريكي ا 30.5الى 16أظهرت نتائج جيدة من خالل تحسين قيم الكثافة من (api وانخفاض انتاج الكبريت من )40وزنًا وزيادة في سعر البيع للبرميل الواحد بنسبة 1.507الى 6.4% .البرميل الواحد من جراء فعاليات تحسين المواصفاتزيادة في كلفة انتاج %2.31مقارنة بـ .البارد، حقل القيارة النفطي الثقيل، تحسين الخام الثقيل، نفط صناعي، كلفة إنتاج النفط الكلمات الدالة: التكسير iraqi journal of chemical and petroleum engineering vol.18 no.1 (march 2017) 71 85 issn: 1997-4884 treatment of simulated oily wastewater by ultrafiltration and nanofiltration processes ahmed faiq al-alawy * and mohammed kamil al-ameri** chemical engineering department, college of engineering, university of baghdad *ahmedalalawy@yahoo.com , **mohammed.k.alameri@gmail.com abstract a study in the treatment and reuse of oily wastewater generated from the process of fuel oil treatment of gas turbine power plant was performed. the feasibility of using hollow fiber ultrafiltration (uf) membrane and nanofiltration (nf) membrane type polyamide thin-film composite in a pilot plant was investigated. three different variables: pressure (0.5, 1, 1.5 and 2 bars), oil content (10, 20, 30 and 40 ppm), and temperature (15, 20, 30 and 40 ᵒc) were employed in the uf process while tds was kept constant at 150 ppm. four different variables: pressure (2, 3, 4 and 5 bar), oil content (2.5, 5, 7.5 and 10 ppm), total dissolved solids (tds) (100, 200,300 and 400 ppm), and temperature (15, 20, 30 and 40 ᵒc) were manipulated with the help of statistical method of taguchi in the ro process. analysis of variable (anova) and optimum condition was investigated. the study shows that pressure has the greatest impact on the flux of uf process, while temperature and pressure have similar contribution on flux of nf process. the temperature seems to have the greatest effect on tds rejection. it was noticed that more than 96% oil removal can be achieved with flux of 624 l/m 2 .hr by uf process and that the fouling mechanism of uf process follows the cake/gel layer filtration model. it was observed that 100% removal of oil content can be achieved along with 79% for the tds rejection and flux of 65 l/m 2 .hr by nf process. the result shows fouling in nf process follows the cake filtration model. it was concluded that the observed values are within ±5% of that the predicted which reflects a strong representative model. the treated wastewater has the characteristics that it can be reused in the process to reduce the operating cost. key words: taguchi, uf, nf, membrane, oily wastewater, reuse. introduction a variety of industrial sources generates large amounts of wastewaters daily. important fractions of these are the oil in water (o/w) emulsions for which current treatment technologies are often costly and ineffective [1]. oily wastewaters are produced by various processes and plants such as oil refineries, petrochemical plants and metalworking plants. these wastewaters create a major ecological problem throughout the world [2]. another source of oily wastewater is the effluent of gas turbine power plants running by crude oil at which the main source of oily university of baghdad college of engineering iraqi journal of chemical and petroleum engineering mailto:ahmedalalawy@yahoo.com mailto:mohammed.k.alameri@gmail.com treatment of simulated oily wastewater by ultrafiltration and nanofiltration processes 72 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net wastewater is the fuel treatment process [3]. oil in water can exist as free, dispersed, emulsified and dissolved oil. the first two forms can be separated from wastewater by simple physical processes. however, emulsified or dissolved oil is more difficult to remove [4]. conventional oily wastewater treatment methods include gravity separation and skimming, dissolved air flotation, deemulsification, coagulation, and flocculation. these methods have several disadvantages such as low efficiency, high operation costs, corrosion and recontamination problems [5]. with the remarkable development in membrane filtration technology these processes now exist as an efficient aid that may have all the features required by the industrial standards and environmental regulations. hence, it is increasingly being applied for treating wastewater from different sources. membranes have several advantages that made it applicable across a wide range of industries, such advantage like the quality of treated water (permeate) is more uniform regardless of influent variations, no chemicals are needed and the possibility for in-process recycling [6]. membrane filtration has been proven effective in treating oily water in different industries including municipal wastewater [7], [8], engine rooms [2] and industrial wastewater [9], [10]. it was also studied in many oily wastewater treatment types of research [11], [12]. ultrafiltration (uf) processes have been introduced as solution for oily wastewater treatment in many studies [1], [2], [9], [13], [14], however, it was noticed that uf processes fail when it comes to meet the removal of ionic contaminations, i.e., the salt ions. reverse osmosis processes (ro) and nanofiltration processes (nf) has found to have higher ability to remove total dissolved solids than that of uf processes [6], [10, 11], [15-17]. therefore, the integration of membrane processes may open the doors for efficient oily wastewater treatment and water reuse [18-20]. taguchi method the conventional technique of studying the effect of multiple factors on the membrane-integrated processes may alter high cost due to a large number of runs and time besides the difficulties of interpretation of these results [21]. in such case, taguchi approach can be applied with confined knowledge of statistics to reduce the number of runs. hence, it was highly adopted and gained wide popularity in engineering application [22] and used in many studies related to wastewater treatment, [13], [15], [23]. taguchi approach can be applied with confined knowledge of statistics hence, got high adaptability and gained wide popularity in engineering application [22], and used in many studies related to wastewater treatment, [13], [15], [23]. the main steps for the experimental design in taguchi method are (1) determination the objective function, (2) identifying the control factors, (3) selection the orthogonal array (oa), (4) running the experiment, (5) analysis of the data and (6) model confirmation, [21]. taguchi method utilizes a statistical measurement of performance known as signal-to-noise (s/n) ratio, in which signal represents the desirable value while noise represents the undesirable value. there are many different possible s/n ratios, however, two of them are applicable in the present experiments: larger is better (ltb) and small is better (stb) [22]. in this study, the larger is better (equation 1) is the flux and tds rejection while the smaller is better for the fouling resistant (equation 2). http://www.iasj.net/ ahmed faiq al-alawy and mohammed kamil al-ameri -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 73 ( ) [ ∑ ] …(1) ( ) [ ∑ ] …(2) where s is the signal, n is the noise, n is the repetition number of each experiment with the same conditions, yi is the response of experiment. fouling resistance and filtration model permeate flux and fouling resistance are key factors for uf and nf process evaluation. flux shows the amount of permeate rate. fouling resistance shows the significance of cake/gel layer on the membrane surface and its effect on flux decline. fouling resistance (rf) was calculated as following [29]: …(3) where: tmp: is the trans membrane pressure, µ is the water viscosity, jwi is the initial water flux, jww is the water flux after fouling. membrane physical structure has an important influence on flux. if the pores are larger than the size of oil droplets, these droplets may enter the pores causing irreversible fouling. when the membrane pores are smaller than the droplets in the feed, these particles/oil droplets accumulate over the membrane surface causing the formation of a cake/gel layer. during membrane filtration, the degree of fouling depends on three main factors: 1) operation factors 2) feed properties and 3) membrane properties. the operational parameters are such an important factors in deciding the rate of membrane fouling, in particular, increasing pressure enhances formation of the cake/gel layer of higher density and finally leads to complete pore blocking [30]. most models of membrane fouling correlate the permeate flux with time in terms of a quadratic and/or exponential relationship by assuming pore blockage, adsorption, gelpolarization, and bio-fouling [10]. the filtration models are listed in table 1. the standard blocking mechanism occurs when the oil droplets are smaller than that of the membrane pores which leads to an internal pore blocking. the complete blocking mechanism occurs when the oil droplets size is greater than that of the membrane pores. as results, particles/oil droplets do not enter into the membrane pores and do not permeate through the membrane. the intermediate blocking mechanism occurs when the size of oil droplets is similar to that of membrane pores leading to the membrane pores to be blocked near their entrances on the feed side. the cake formation mechanism occurs when the size of oil droplets is much greater than the pore size; hence they are unable to enter the membrane pores. factors affecting this type of mechanism are oil droplets deformation, cake compression, and cake/gel layer thickness. table 1: equations of filtration models filtration model fouling mechanism ref. complete pore blocking [31] ⁄ ⁄ standard pore blocking [32] ⁄ ⁄ intermediate pore blocking [33] ⁄ ⁄ cake filtration [27] http://www.iasj.net/ treatment of simulated oily wastewater by ultrafiltration and nanofiltration processes 74 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net experimental work wastewater feed oily wastewater feed used in this experiment was prepared using untreated crude and reverse osmosis permeates water. the mixture was then agitated for one minute using 10,000 rpm homogenizer type ultra turrax t46/6 by janke and kunkel kg. an emulsifier with hypophilic-lipophilic balance (hlb) value of 7 was added as a 1% as weight percentage of the untreated crude to ensure emulsion stabilization, the emulsifier is a proper quantities mix of tween 85 and span 80 both by thomas baker, the selection of desired hlb value and the weight percentage was based on some experiments done to evaluate the emulsion stability. it was noticed that with the above-selected conditions the emulsion can still stable for more than two weeks of observation. tds value was controlled using lab grade nacl by sigma-aldrich. membrane system figure 1 shows a schematic view of the experiment setup. the system consists of one pvc type hollow fiber uf membrane with molecular weight cutoff of 50k dalton and surface area of 2 m 2 . the uf membrane model bn90 and was supplied by guangzhou chunke environmental technology co. ltd. from china. the system consists also of polyamide thin-film composite nf membrane type nf32540 by axeon usa with an active area of 2.69 m 2 . a 100 liter glass tank and nsf brass 140 gph rotary vane pump by procon usa is driven by procon's 1/2 hp motor where used as feed tank and ro feed pump respectively. a centrifugal pump type pkm 90 by pedrollo co. was used as uf feed pump. pressure gauges are installed at the module inlet and rejection stream, flow meters used to measure permeate and rejection flow rate, throttle valve used at the rejection stream to control the pressure. four control factors were chosen in this work: temperature, pressure, total dissolved solids, and oil concentration, while the time was kept constant at 30 minutes, the factors and their levels are shown in table 2. the chosen of the above operation condition was based on real wastewater collected from gas turbine power plant's wastewater treatment facility where its oil contents are 39 ppm, tds is 150 ppm. the taguchi design of experiment (doe) was used and an orthogonal array of 16 runs (l16) was selected as the least number of experiments can be performed to evaluate the effects of above different factors in the uf and nf process. flux and removal efficiency were evaluated as in equation 4 (flux calculations) and equation 5 (removal efficiency): …(4) …(5) where, j = flux, (l/hr.m2), qp = permeate flow rate (l/hr) and am = surface area of membrane (m 2 ), ci and cp are initial and permeate concentration of the property respectively. press flowpress flow temp heater cool temp heater cool flow flow tank 2 pump 2 high pressure pump pump 1 low pressure pump tank 1 circulation line circulation line ufnf press press temperature control heating/cooling temperature control heating/cooling uf product to nf/ro feed line press fig. 1: experiment setup http://www.iasj.net/ ahmed faiq al-alawy and mohammed kamil al-ameri -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 75 table 2: factors used with their levels uf process nf process 1 2 3 4 1 2 3 4 temp (ᵒc) 15 20 30 40 15 20 30 40 p (bar) 0.5 1 1.5 2 2 3 4 5 tds (ppm) 150 150 150 150 100 200 300 400 oil (ppm) 10 20 30 40 2.5 5 7.5 10 results and discussion uf process table 3 represents the experimental results for uf process. it was found that oil removal for uf process exceeds the 96% for all the experimental runs, hence it was not considered as a response and was not included in the optimization process. figure 2 represents the main effect plot for s/n ratio using the "larger is better". the figure indicates that maximizing pressure and temperature will increase the s/n ratio. table 3: results of uf process experiments t ᵒc oil ppm p bar flux lmh oil % turb.% 15 10 0.5 118.3 99.8 95.1 15 20 1.0 224.3 99.6 95.0 15 30 1.5 272.8 99.5 95.4 15 40 2.0 345.9 99.6 95.9 20 20 0.5 124.9 99.7 95.4 20 10 1.0 254.8 99.6 95.1 20 40 1.5 298.4 99.4 96.7 20 30 2.0 383.8 99.0 94.7 30 30 0.5 136.3 99.7 96.6 30 40 1.0 249.1 99.2 97.5 30 10 1.5 422.7 98.5 95.0 30 20 2.0 541.3 97.3 94.2 40 40 0.5 153.1 99.5 98.3 40 30 1.0 284.9 98.4 96.0 40 20 1.5 431.1 97.6 94.5 40 10 2.0 618.3 96.0 95.0 figure 3 represents the effect of temperature and pressure on oil removal. it was found that higher pressure will lead to lower oil removal; this may be attributed to the fact that the increase in pressure may deform the oil droplet and push it through the pores. the temperature effect on oil removal is increasing at elevated pressure. for example, the increase in temperature from 20 to 30 ᵒc will decrease the oil removal by 0.2% and 2% at pressure of 0.5 and 2 bars respectively. the negative effect of temperature on the oil removal is due to the pore opening and reduction in oil viscosity. fig. 2: s/n ratio for flux of uf process fig. 3: effect of temperature and pressure on oil removal figure 4 represents the flux at different temperature and oil values. the figure indicates that the oil content decreases the flux linearly. the figure also indicates that the increase in oil concentration will decrease the percentage increase of flux with temperature. for example, the increase in temperature from 20 to 30 ᵒc will http://www.iasj.net/ treatment of simulated oily wastewater by ultrafiltration and nanofiltration processes 76 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net increase the flux by 7% when the oil contents are 10 ppm, however, the increase will only be 1.7% when the oil concentration is 30 ppm. this is a result of the cake layer formation which is higher when the oil concentration is high. fig. 4: effect of temperature on flux of uf process at different oil content (p=2 bar) analysis of variables was conducted for the flux data. the results are represented in table a.1. the adequacy of the suggested model can be predicted from the residual plots of figure 5. the anova analysis suggests that the greatest contribution to the flux comes from the pressure and that p-value assumes that all the model parameters are significant. the model presented has an r 2 of 99.9%. fig. 5: residual plots for flux of uf process the flux from experimental runs of temperature equal to 30 ᵒc, pressure of 1 bar and oil of 20 ppm were used to evaluate the fouling mechanism. figure 6 shows the flux decline with time. figure 7 shows different forms of flux with time. the figure indicates that the cake filtration model is the best fits the experimental runs. fig. 6: flux of uf process vs time an optimization process was utilized using minitab 17 software on uf process results. the aim of this process was to increase flux and reduce the fouling resistance. the optimum operation conditions are listed in table 4. a confirmation experiment was conducted and the observed vs. the predicted values are shown in table 5. the table shows that the deviation from the prediction is around 1% which reflects a strong proposed model. fig. 7: different forms of flux for uf process vs. time table 4: optimmum operation conditions for uf process variable setting temp (ᵒc) 40 p (bar) 1.97 oil (ppm) 10 predicted flux (l/hr.m 2 ) 618.3 table 5 predicted vs observed results for uf process confirmation test parameters observed value deviation flux (l/hr.m 2 ) 6.426 1.2% oil removal% 96.6 250200150100500 275 270 265 260 255 250 time (min) f lu x ( l m h ) scatterplot of flux (lmh) vs time (min) http://www.iasj.net/ ahmed faiq al-alawy and mohammed kamil al-ameri -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 77 nf process table 6 shows the l16 orthogonal array results for nf process. it was found that oil removal is 100% for all the experimental runs. hence, it will not be considered as a response and not included in the optimization process due to the high error that may be encounter in model. figure 8 and figure 9 represents the main effect plots for s/n of flux and tds rejection respectively. figure 8 show that both pressure and temperature have positive effect on flux s/n ratio increase while both oil and tds have a negative effect. this is as the pressure increases the driving force, temperature reduces the resistance to transfer, tds increases the osmotic pressure and oil increases the fouling and resistance of mass transfer. figure 9 shows negative effect of temperature and tds on tds rejection s/n ratio while the effect of pressure is positive. the figures also indicate that the presence of oil in feed increases the tds rejection and the steepest slope can be noticed at oil concentration of 7.5 to 10 ppm. this may be due to the blocking of membrane pore and reducing the salt passage. table 6: experimental results for nf process t ᵒc oil ppm tds ppm p bar flux lmh tds rejection% 15 2.5 100 2 12.2 81 15 5.0 200 3 18.6 82 15 7.5 300 4 21.0 85 15 10.0 400 5 29.5 89 20 2.5 200 4 33.2 80 20 5.0 100 5 42.5 83 20 7.5 400 2 9.5 75 20 10.0 300 3 22.0 82 30 2.5 300 5 61.0 74 30 5.0 400 4 47.1 75 30 7.5 100 3 34.0 80 30 10.0 200 2 21.0 77 40 2.5 400 3 45.5 66 40 5.0 300 2 29.7 68 40 7.5 200 5 77.0 74 40 10.0 100 4 63.5 75 the results of anova for nf process are listed in table a.2 and table a.3 for flux and tds rejection respectively. the analysis suggests flux modeling and tds rejection modeling with r2 of 99.67% and 99.65% respectively. fig. 8: s/n ratio for flux of nf process fig. 9: s/n ratio for tds rejection of nf process residuals versus order plot indicate that there are systematic effects in the data that may be related to the time or data collection order. normal probability and histogram plots http://www.iasj.net/ treatment of simulated oily wastewater by ultrafiltration and nanofiltration processes 78 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net showing that outlier's data do not exist. both figures summarize that there is no obvious pattern and unusual structure. the residual analysis does not indicate model inadequacy. figure 12 shows the flux decline of nf process vs time at operation condition of temperature equal to 25 ᵒc, pressure of 6 bars, oil contents of 5 ppm and tds of 200 ppm. the flux data were represented in different forms as ln (j), 1/j0.5, 1/j and 1/j 2 vs time in figure 13 which indicates that the fouling in nf process follow the cake filtration model. fig. 10: residual plots for flux modeling of nf process fig. 11: residual plots for tds rejection modeling of nf process fig. 12: flux decline with time for nf process at operation condition of t= 25 c, p= 6 bar, oil = 5 ppm and tds =200 ppm fig. 13: different forms of flux (j) with time for nf process at operation condition of t= 25 ᵒc, p= 6 bar ,tds= 200 ppm and oil = 5 ppm an optimization process was conducted using minitab software package to increase both flux, tds rejection and reduce the fouling resistance. the optimum operation conditions are listed in table 7. a confirmation experiment was conducted and the observed vs. the predicted values are shown in table 8. the table shows that the deviation from the prediction is less than 5% which reflects a strong proposed model. table 7: optimmum operation conditions for nf process variable setting temp (ᵒc) 31 p (bar) 5 oil (ppm) 7 tds (ppm) 100 predicted flux (l/hr.m 2 ) 62.7 predicted tds rej.% 78 table 8: predicted vs observed results for nf process confirmation test parameters observed value deviation flux (l/hr.m 2 ) 65.9 4.7% tds rejection% 79 1.2% oil removal% 100 figure 14 represents the scatter plot of the nf process flux as a response to temperature and pressure with a constant oil concentration of 5 ppm and tds of 200 ppm. the figure shows that both temperature and pressure have a positive effect on the 250200150100500 53.25 53.00 52.75 52.50 52.25 52.00 51.75 51.50 time (min) f lu x ( l m h ) scatterplot of flux (lmh) vs time (min) http://www.iasj.net/ ahmed faiq al-alawy and mohammed kamil al-ameri -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 79 flux and the effect of one parameter decreases slightly with the other parameter increase. for example, the increase of pressure from 3 to 4 bars increases the flux by 40% and 34.5% at a temperature of 20 and 40 ᵒc respectively. similarly, the increase in temperature from 20 to 40 ᵒc increases the flux by 101.3% and 93% at a pressure of 3 and 4 bars respectively. these findings indicate limited effect of oil. the increase of pressure will increase the driving force, the increase in temperature increases the pore size and reduce the viscosity hence it will reduce the resistance for transfer through membrane walls. fig. 14: flux of nf process vs temperature and pressure (tds=200 ppm, oil =5 ppm) figure 15 represents the scatter plot of the nf process flux as a response for tds and pressure with constant temperature of 30 ᵒc and oil concentration of 5 ppm. the figure shows a negative effect on the flux when tds increases as a result of increasing the osmotic pressure. the effect of increasing the tds on flux decline seems to be limited when compared with pressure. however, the decline is less at higher pressure. for example, the increase of tds from 100 ppm to 400 ppm leads to 8.3% and 6% decrease in flux at a pressure of 3 and 4 bars respectively. another example is that increasing the pressure from 3 to 4 bars results in 35.5% and 38.4% increase of flux at tds equal to 100 and 400 ppm respectively. fig. 15: flux of nf process vs tds and pressure (temperature =30 ᵒc, oil =5 ppm) figure 16 represents the scatter plot of the flux of nf process as a response to temperature and tds at a constant pressure of 3 bars and oil of 5 ppm. as it is the case with the tds-pressure effect, the tds seems to have a lower effect on flux decline than that of temperature and this effect is decrease as the temperature increase. for example, increasing the tds from 100 ppm to 400 ppm leads to 9% and 8.3% decrease in flux at a temperature of 20 ᵒc and 30ᵒc respectively. the tds seems to have limited effect on flux increase when increasing the temperature. for example, increasing the temperature from 20 ᵒc to 30 ᵒc increases the flux by 48.1% and 50% at feed tds value of 100 ppm and 400 ppm respectively. fig. 16: flux of nf process vs tds and temperature (pressure= 3 bars, oil =5 ppm) figure 17 represents the scatter plot of the flux of nf process as a response to pressure and oil at a constant temperature of 30 ᵒc and tds of 200 ppm. the figure shows the negative http://www.iasj.net/ treatment of simulated oily wastewater by ultrafiltration and nanofiltration processes 80 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net effect of oil on flux decline. the figure also indicates that the effect of oil is less at higher pressure. for example, the increase of oil concentration from 2.5 to 10 ppm leads to 9.1 and 4.2% decrease in pressure of 2 and 5 bars respectively. fig. 17: flux of nf process vs oil and pressure (temperature =30 ᵒc, tds =200 ppm) figure 18 represents the scatter plot of the flux of nf process as a response to temperature and oil at a constant pressure of 3 bars and tds of 200 ppm. the figure shows the negative effect of oil on flux decline. the figure also indicates that the effect of oil is less at a higher temperature. for example, the increase of oil concentration from 5 to 10 ppm leads to 6.3% and 3.4% decreases in temperature of 20 and 40 ᵒc respectively. fig. 18: flux of nf process vs oil and temperature (tds =200 ppm, pressure =3 bar) figure 19 represents the scatter plot of the flux of nf process as a response to tds and oil at a constant pressure of 3 bars and temperature of 30 ᵒc. the figure shows that both oil and tds have a negative effect on flux decline due to the increase of gel/cake layer and the concentration polarization. the increase of oil concentration from 5 to 10 ppm decreases the flux by 5%. the increase of tds from 100 to 400 ppm decreases the flux by 8.5%. fig. 19: flux of nf process vs tds and oil (temperature =30 ᵒc, pressure =3 bar) figure 20 represents the scatter plot of tds rejection percentage of nf process as a response to temperature and pressure at constant oil and tds concentration of 5 and 200 ppm respectively. the figure shows that increasing the pressure increases the tds rejection while increasing the temperature will decrease the tds rejection. the figure indicates that the higher the pressure the higher effect of temperature on tds rejection decrease and the lower the temperature the higher effect of pressure on tds rejection increase. for example, increasing the temperature from 20 to 40 ᵒc decreases the tds rejection by 10.5 and 20% at pressure 3 and 4 bars respectively. oppositely, the increase of pressure from 3 to 4 bars will increase the tds rejection by 6 and 2.5% at a temperature of 20 and 40 ᵒc respectively. increasing the pressure increases the driving force of the water leading to more quantity of water to pass the membrane pore and hence more diluted permeate. the increase in temperature leads to wider membrane pore opening, an increase of solubility http://www.iasj.net/ ahmed faiq al-alawy and mohammed kamil al-ameri -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 81 of nacl in water and decrease in water viscosity resulting in less friction with membrane walls. these can lead to salt passage and hence decrease the removal efficiency. fig. 20: tds rejection vs pressure and temperature (tds =200 ppm, oil =5 ppm) figure 21 represents the scatter plot for the tds rejection% of nf process as a response to pressure and tds at constant temperature value feed of 30 ᵒc and oil of 5 ppm. the figure shows that the effect of increasing tds is neglected at higher pressure. for example increasing tds from 100 to 400 ppm decreases the tds rejection by 9% at a pressure of 2 bars while it will not have any impact at a pressure of 5 bars. these findings are differing from that of oil-free feed where the tds have a negative effect at all pressure values. fig. 21: tds rejection vs tds and pressure (temperature= 30ᵒc, oil =5 ppm) figure 22 represents scatter plot for the tds rejection% of nf process as a response to temperature and tds at a constant pressure value of 3 bars and oil of 5 ppm. the figure shows a negative effect of temperature and tds concentration on the tds rejection. it also shows that as the tds increase, the temperature should be decreed more to maintain the tds rejection at a specific zone. fig. 22: tds rejection vs tds and temperature (pressure= 3 bars, oil =5 ppm) figure 23 represents scatter plot for the tds rejection% of nf process as a response to pressure and oil at a constant temperature of 30 ᵒc and oil concentration of 5 ppm. the figures show that increasing the oil and pressure increases the tds rejection. this may be attributed to the fact that oil droplet will build the gel/cake layer that acts as additional resistance to the salt transfer. fig. 23: tds rejection vs pressure and oil (temperature= 30ᵒc, tds =5 ppm) figure 24 represents scatter plot for the tds rejection% of nf process as a response to temperature and oil at a constant pressure of 3 bars and tds concentration of 200 ppm. the figure shows that increasing the temperature decreases the tds rejection while increasing the oil concentration will http://www.iasj.net/ treatment of simulated oily wastewater by ultrafiltration and nanofiltration processes 82 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net shift the tds rejection to a higher zone. fig. 24: tds rejection vs oil and temperature (pressure= 3 bars, tds =200 ppm) figure 25 represents scatter plot for the tds rejection% of nf process as a response for tds and oil at a constant pressure of 3 bars and temperature of 30 ᵒc. the figure shows that increasing the tds decreases the tds rejection while increasing the oil concentration increases the tds rejection. fig. 25: tds rejection of nf process vs oil and tds (pressure= 3 bars, temperature=30 ᵒc) conclusions in this study, taguchi design of experiments (l16) was employed to analyze the different parameters contribution on the simulated oily wastewater treatment using a hollow fibers uf membrane and polysulfone nf membrane. according to the anova analysis, the most important parameter for maximum permeate flux was the pressure for uf process, while the temperature and pressure had equal effect on flux of nf process. however, the anova analysis shows that the temperature had the greatest contribution on tds rejection. process optimization was conducted using statistical software. optimum conditions for uf were pressure= 2 bar, temperature= 40 ᵒc, and oil =10 ppm. the results showed that an oil removal of 96% reached with a flux of 624.6 l/m2.hr. the optimum conditions for the nf membrane to provide the highest flux and tds rejection with the lowest resistance was found at pressure = 5 bars, tds=100 ppm, oil =7 ppm, and temperature = 31 ᵒc. the results showed that the treated wastewater contains no oil with low tds value. the study suggests that the produced permeate can be reused in the process of fuel oil washing to reduce the operating cost. nomenclature symbol definition units am membrane surface area m 2 anova analysis of variance cf feed concentration g/l cp permeate concentration g/l c concentration of solute g/l dof degree of freedom hlb hypophiliclipophilic balance value jww flux after fouling l/m 2 .hr jwi initial flux l/m 2 .hr j0 flux of distilled water l/m 2 .hr ms mean of squares p pressure bar μ viscosity kg/(s·m) rf resistances of the foulants 1/m ss sum of square sst total sum of square http://www.iasj.net/ ahmed faiq al-alawy and mohammed kamil al-ameri -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 83 t temperature ᵒc tds total dissolved solids ppm tmp trans-membrane pressure bar s/n signal to noise ratio appendix table a. 1: anova of uf experiment and prediction model for flux source df seq ss contribution adj ss adj ms f-value p-value temp (ᵒc) 1 17723 1.19% 849.6 849.6 48.76 0.000 p (bar) 1 1465218 98.27% 34784.8 34784.8 1996.42 0.000 oil (ppm) 1 3839 0.26% 911.5 911.5 52.32 0.000 temp (ᵒc)*temp (ᵒc) 1 112 0.01% 111.5 111.5 6.40 0.014 p (bar)*p (bar) 1 76 0.01% 75.7 75.7 4.34 0.042 temp (ᵒc)*p (bar) 1 645 0.04% 644.9 644.9 37.01 0.000 temp (ᵒc)*oil (ppm) 1 1774 0.12% 1774.4 1774.4 101.84 0.000 p (bar)*oil (ppm) 1 664 0.04% 664.1 664.1 38.11 0.000 error 55 958 0.06% 958.3 17.4 total 63 1491009 100.00% flux ( l/m 2 .hr ) = -82.71 + 3.342 temp (ᵒc) + 278.90 p (bar) + 1.239 oil (ppm) 0.02033 temp (ᵒc)*temp (ᵒc) 4.35 p (bar)*p (bar) + 0.5914 temp (ᵒc)*p (bar) 0.04905 temp (ᵒc)*oil (ppm) 0.5154 p (bar)*oil (ppm) table a. 2: anova of nf experiment and prediction model for flux source df seq ss contribution adj ss adj ms f-value p-value regression 5 5606.01 99.67% 5606.01 1121.20 607.61 0.000 temp (ᵒc) 1 2692.58 47.87% 2.95 2.95 1.60 0.235 oil (ppm) 1 24.31 0.43% 14.21 14.21 7.70 0.020 tds (ppm) 1 75.86 1.35% 18.58 18.58 10.07 0.010 p (bar) 1 2616.33 46.52% 13.09 13.09 7.09 0.024 temp (ᵒc)*p (bar) 1 196.94 3.50% 196.94 196.94 106.73 0.000 error 10 18.45 0.33% 18.45 1.85 total 15 5624.46 100.00% flux (lmh) = -3.97 + 0.153 temp (ᵒc) 0.338 oil (ppm) 0.01006 tds (ppm) + 2.453 p (bar)+ 0.3423 temp (ᵒc)*p (bar) table a. 3: anova of nf experiment and prediction model for tds rejection source df seq ss contribution adj ss adj ms f-value p-value regression 6 534.993 99.65% 534.993 89.1656 430.51 0.000 temp (ᵒc) 1 381.610 71.08% 11.257 11.2572 54.35 0.000 oil (ppm) 1 56.785 10.58% 53.870 53.8699 260.10 0.000 tds (ppm) 1 22.684 4.23% 26.480 26.4799 127.85 0.000 p (bar) 1 55.445 10.33% 1.501 1.5014 7.25 0.025 temp (ᵒc)*p (bar) 1 4.391 0.82% 4.391 4.3914 21.20 0.001 tds (ppm)*p (bar) 1 14.078 2.62% 14.078 14.0783 67.97 0.000 error 9 1.864 0.35% 1.864 0.2071 total 15 536.858 100.00% tds rejection% = 85.73 0.3006 temp (ᵒc) + 0.6587 oil (ppm) 0.03947 tds (ppm) + 1.048 p (bar) 0.0511 temp (ᵒc)*p (bar) + 0.007832 tds (ppm)*p (bar) references 1. j. marchese, n. a. ochoa, c. pagliero, and c. almandoz, “pilotscale ultrafiltration of an emulsified oil wastewater,” environ. sci. technol., vol. 34, no. 14, pp. 2990– 2996, 2000. http://www.iasj.net/ treatment of simulated oily wastewater by ultrafiltration and nanofiltration processes 84 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net 2. k. karakulski, a. kozlowski, and a. w. morawski, “purification of oily wastewater by ultrafiltration,” sep. technol., vol. 5, no. 4, pp. 197–205, 1995. 3. h. kaplan and k. e. majchrzak, “liquid fuel treatment systems,” ger-3481, general electric. 1996. 4. g. r. alther, “oils found in wastewater, what are they?, how to separate and eliminate them from wastewater, a layman’s guide to emulsion breaking,” no. 248, 2014. 5. y. s. li, l. yan, c. b. xiang, and l. j. hong, “treatment of oily wastewater by organic–inorganic composite tubular ultrafiltration (uf) membranes,” desalination, vol. 196, no. 1, pp. 76–83, 2006. 6. s. mondal and s. r. wickramasinghe, “produced water treatment by nanofiltration and reverse osmosis membranes,” j. memb. sci., vol. 322, no. 1, pp. 162–170, 2008. 7. k. c. channabasappa, “membrane technology for water reuse application,” desalination, vol. 23, no. 1, pp. 495–514, 1977. 8. b. nicolaisen, “developments in membrane technology for water treatment,” desalination, vol. 153, no. 1, pp. 355–360, 2003. 9. j.-j. qin, m. h. oo, h. lee, and r. kolkman, “dead-end ultrafiltration for pretreatment of ro in reclamation of municipal wastewater effluent,” j. memb. sci., vol. 243, no. 1, pp. 107–113, 2004. 10. a. salahi, t. mohammadi, and f. rekabdar, “reverse osmosis of refinery oily wastewater effluents,” iranian j. environ. health sci. eng., vol. 7, no. 5, pp. 413–422, 2010. 11. a. orecki and m. tomaszewska, “the oily wastewater treatment using the nanofiltration process,” polish j. chem. technol., vol. 9, no. 4, pp. 40–42, 2007. 12. a. rahimpour, b. rajaeian, a. hosienzadeh, s. s. madaeni, and f. ghoreishi, “treatment of oily wastewater produced by washing of gasoline reserving tanks using selfmade and commercial nanofiltration membranes,” desalination, vol. 265, no. 1, pp. 190–198, 2011. 13. j. k. milić, i. petrinić, a. goršek, and m. simonič, “ultrafiltration of oil-in-water emulsion by using ceramic membrane: taguchi experimental design approach,” cent. eur. j. chem., vol. 12, no. 2, pp. 242–249, 2014. 14. s. santos and m. wiesner, “ultrafiltration of water generated in oil and gas production ”,7991 . 15. s. s. madaeni and s. koocheki, “application of taguchi method in the optimization of wastewater treatment using spiral-wound reverse osmosis element,” chem. eng. j., vol. 119, no. 1, pp. 37–44, 2006. 16. e. park and s. m. barnett, “oil/water separation using nanofiltration membrane technology,” sep. sci. technol., vol. 36, no. 7, pp. 1527–1542, 2001. 17. m. s. h. bader, “nanofiltration for oil-fields water injection operations: analysis of concentration polarization,” desalination, vol. 201, no. 1, pp. 106–113, 2006. 18. m. tomaszewska, a. orecki, and k. karakulski, “treatment of bilge water using a combination of ultrafiltration and reverse osmosis,” desalination, vol. 185, no. 1–3, pp. 203–212, nov. 2005. 19. x. yu, z. zhong, and w. xing, “treatment of vegetable oily wastewater using an integrated microfiltration-reverse osmosis system,” in water science and http://www.iasj.net/ ahmed faiq al-alawy and mohammed kamil al-ameri -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 85 technology, 2010, vol. 61, no. 2, pp. 455–462. 20. a. salahi and t. mohammadi, “experimental investigation of oily wastewater treatment using combined membrane systems,” water sci. technol., vol. 62, no. 2, pp. 245–255, 2010. 21. r. k. roy, a primer on the taguchi method. society of manufacturing engineers, 2010. 22. e. r. ziegel, “taguchi techniques for quality engineering,” technometrics, vol. 39, no. 1, pp. 109–110, 1997. 23. a. salahi, t. mohammadi, r. m. behbahani, and m. hemmati, “experimental investigation and modeling of industrial oily wastewater treatment using modified polyethersulfone ultrafiltration hollow fiber membranes,” korean j. chem. eng., pp. 1–18, 2015. 24. n. eliaz, g. shemesh, and r. m. latanision, “hot corrosion in gas turbine components,” eng. fail. anal., vol. 9, no. 1, pp. 31–43, 2002. 25. l. yu, m. han, and f. he, “a review of treating oily wastewater,” arab. j. chem., 2013. 26. i. w. cumming, r. g. holdich, and i. d. smith, “the rejection of oil by microfiltration of a stabilised kerosene/water emulsion,” j. memb. sci., vol. 169, no. 1, pp. 147–155, 2000. 27. a. b. koltuniewicz, r. w. field, and t. c. arnot, “cross-flow and dead-end microfiltration of oilywater emulsion. part i: experimental study and analysis of flux decline,” j. memb. sci., vol. 102, pp. 193–207, 1995. 28. a. salahi, t. mohammadi, f. rekabdar, and h. mahdavi, “reverse osmosis of refinery oily wastewater effluents,” iranian j. environ. health sci. eng., vol. 7, no. 5, p. 413, 2010. 29. m. kazemimoghadam and t. mohammadi, “chemical cleaning of ultrafiltration membranes in the milk industry,” desalination, vol. 204, no. 1, pp. 213–218, 2007. 30. s. m. kumar and s. roy, “recovery of water from sewage effluents using alumina ceramic microfiltration membranes,” sep. sci. technol., vol. 43, no. 5, pp. 1034–1064, 2008. 31. h. susanto, y. feng, and m. ulbricht, “fouling behavior of aqueous solutions of polyphenolic compounds during ultrafiltration,” j. food eng., vol. 91, no. 2, pp. 333–340, 2009. 32. m. c. v. vela, s. á. blanco, j. l. garcía, and e. b. rodríguez, “analysis of membrane pore blocking models applied to the ultrafiltration of peg,” sep. purif. technol., vol. 62, no. 3, pp. 489– 498, 2008. 33. j. kim, a. chinen, and h. ohya, “membrane microfiltration of oily water,” in macromolecular symposia, 1997, vol. 118, no. 1, pp. 413–418. http://www.iasj.net/ available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.21 no.2 (june 2020) 25 – 35 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: ola a. nashmi, email: olawissam86@gmail.com, name: ahmed a. mohammed, email: ahmed.abedm@yahoo.com, name: nada n. abdulrazzaq, email: nnabdulrazzaq@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. investigation of ozone microbubbles for the degradation of methylene orange contaminated wastewater ola a. nashmi a , ahmed a. mohammed a and nada n. abdulrazzaq b a environmental engineering department, college of engineering, university of baghdad b chemical engineering department, college of engineering, university of baghdad abstract in the present study, semi – batch experiments were conducted to investigate the efficiency of ozone microbubbles (ombs) in the treatment of aqueous dye solutions methylene orange under different reaction conditions such as effect of initial solution ph , ozone generation rate and initial mo-concentration. the results showed that the removal of mo by ombs were very high at the acidic and alkaline media and upon increasing the generation rate of ozone from 0.498 to 0.83 mg/s, the removal efficiency dramatically increased from 75to 100% within 15 min. the rate of oxidation reaction followed a pseudo firstorder kinetic model. the results demonstrated that ombs is efficient in terms of the decline of methylene orange concentration and its total mineralization. keywords: methylene orange, ozone microbubble, ozone generation rate, removal efficiency received on 13/10/2019, accepted on 23/02/2020, published on 30/06/2020 https://doi.org/10.31699/ijcpe.2020.2.4 1introduction organics contamination has long been a serious environmental issue and has drawn much attention .organic contaminants, such as, petrochemicals, dyes, and agrochemicals are major pollutant in wastewater, and can be extremely harmful to the environment and the human body [1]. dyes are toxic contaminants in water and wastewater which causes remarkable threat to the environment if their concentration exceeds the acceptable limits [2]. they can remain in the environment for a long period of time if they are not addressed with an adequate treatment [3, 4]. in fact, the direct dye discharge that containing effluents into water is unfavorable, and that’s not related to their color only, but also because various of these released dyes and their breakdown products be toxic, mutagenic or carcinogenic to life forms mainly owing to carcinogens, for instance benzidine , naphthalene and other aromatic compounds [5, 6]. several technologies had been designed to remove such pollutants, as well as these technologies include chemical oxidation, physical adsorption, and biological processes [7]. nevertheless, physical adsorption removal efficiency is extremely restricted for wastewater that contains complicated components [8]. biological treatment techniques are ineffective for fairly persistent contaminants and typically required more time in comparison with chemical processes [9]. in addition, in the biological methods the microbial activities are extensively affected by the environmental conditions that around it, consequently, it was inappropriate for several cases like the therapy of wastewater with high salinity [10]. chemical oxidation is the commonly used method for the treatment of organics contaminated wastewater [11, 12]. it is better than biological procedures and can be utilized for treating some consistent contaminants [9]. in chemical oxidation method, the oxidants that are used can competently break down organic contaminants and change it into less significant compounds or even convert them into water and carbon dioxide [13]. the best oxidant was chosen as a especially good agent for wastewater treatment is ozone for the reason that its strong oxidation ability [14]. it is commonly used to treat the pharmaceuticals present in water [15], and it may be used as a primary treatment to alter persistent contaminants into further more biodegradable compounds [16]. the rate of ozone mass transfer can be greatly enhanced by microbubble dispersal [17]. micro bubble technology (mbs) were used extensively to get better based –advanced ozone oxidation processes for the treatment of water and wastewater because of their important physicochemical properties, mbs have a lower rising velocity in comparison with normal bubbles, and the negative charge of their shell, prevent them from coalescence, as a result, they are remain in water for a longer period of time [18]. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:olawissam86@gmail.com mailto:ahmed.abedm@yahoo.com mailto:nnabdulrazzaq@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2020.2.4 o. a. nashmi et al. / iraqi journal of chemical and petroleum engineering 21,2 (2020) 25 35 26 moreover, mbs possess large specific surface area and high internal pressure, and that is can be able to improve the rate of mass transfer from bubbles into the aqueous phase significantly, so as a result, more dissolved gas concentration in the liquid phase [19, 20]. mbs can be combined with ozone effectively for their appliance in wastewater treatment. mbs can extend the reactivity and furthermore increases the dissolved ozone concentration [21], thereby increasing the treatment efficiency of ozone. these properties are of great significance and effective in the term of enhancing the transfer of ozone into water and production of hydroxyl radicals, the hydroxyl radical (·oh) is a strong oxidant with a standard redox potential of 2.8 v [22]. consequently, the application of ozonation micro bubbles possibly an efficient alternative option for complete mineralization of mo from water. this study investigated the possibility and efficiency of utilization of the ozone micro bubbles in the simulated waste water treatment. methylene orange (an important /panionic dye), was selected as the target contaminant to facilitate the influence of initial ph, initial mo concentration, ozonation rate and determination of mass transfer coefficient. the results proved that the use of ozonation micro bubbles was a promising technology for total removal of mo from water with the bubble diameter size determined by (imagej free software) on average was (32) micrometer. 2mechanism of ozonation oxidation of dye particles in general, includes the oxidant assault on the sulfonic group or assault on the binary bond between n molecules (azo dyes). despite the fact that the break of dye atoms is adequate to wipe out undesirable shading, different mixes are delivered during oxidation, which is once in a while hard to change over [23]. ozonation might be a promising process for color degradation that is providing advantages such as its be able to degrade in cooperation color and organic pollutant in the one step, with no chemical sludge remaining after the process, and have less danger for the reason that residual ozone can be decomposed easily to oxygen in water [24] and no stock of any chemical (like hydrogen peroxide) is critical. depending on the media ph, ozone reactions were divided in to two reactions that are direct or indirect reaction. at acidic solution ph, the rate of ozone decomposition was very slow and negligible; therefore, as indicated by the responses given below [25], atomic ozone responds straightforwardly with organics or inorganics and oxidizes them: 𝑂3 + 𝑂𝑟𝑔𝑎𝑛𝑖𝑐𝑠 → 𝐵𝑦 − 𝑝𝑟𝑜𝑑𝑢𝑐𝑡𝑠 + 𝐻2𝑂 + 𝐶𝑂2 (1) 𝑂3 + 𝑂𝑟𝑔𝑎𝑛𝑖𝑐𝑠 → 𝐻𝑂 · + 𝐵𝑦 − 𝑝𝑟𝑜𝑑𝑢𝑐𝑡𝑠 + 𝐻2𝑂 + 𝐶𝑂2 (2) when the dye molecules were oxidized by ozone, first of all it assaults the dye chromophore group as well as break down its construction [26, 27]. in accordance with the literature, molecular ozone reacts with organics such as phenols, aromatic compounds and amines easily; however, alternatively, the reaction of aldehydes, carboxylic acids and alcohols occurs more slowly with ozone [28]. observably, it is able to conclude that the direct and indirect ozone reactions are selective and depends on the target compound. when ph exceeds 7, ozone decomposition starts to occur by the reaction of hydroxyl ions (oh ) with o3. ozone decomposition provides the formation of hydroxyl radicals and enhances the hydroxyl radical reactions with organics [29]. chu et al. [24] and oyama et al. [30] had been mentioned that at acidic ph, molecular ozone reacts with organics and at ph values more than 7, the high rate of ozone decomposition causes the indirect reactions between hydroxyl radicals and organics to take place. staehelin et al. [31] proposed the possible decomposition reaction of ozone as follows: 𝑂3 + 𝑂𝐻−→ 𝐻𝑂2 · + − 𝑂2 ∙ (3) initially, starting with the self-decomposition reaction of ozone, indirect oxidation reactions improved with ho proceed to occur generally in alkaline medium. after ozone decomposition, the following reactions in aqueous phase occur: 𝑂2 − · + 𝑂3 → 𝑂3 − · + 𝑂2 (4) 𝑂3 − · + 𝐻+ → 𝐻𝑂 · + 3𝐻𝑂 · + 𝑂2 (5) 𝑂3 + 𝐻𝑂 · → 𝐻𝑂2 · + 𝑂 (6) 𝑂𝑟𝑔𝑎𝑛𝑖𝑐𝑠 + (𝐻𝑂 · , 𝑂2 − · , 𝑂3 − · ) → 𝐵𝑦 − 𝑝𝑟𝑜𝑑𝑢𝑐𝑡𝑠 + 𝐶𝑂2 + 𝐻2𝑂 (7) therefore, in the ozonation method, both direct and indirect oxidations by ozone and hydroxyl radicals were of great importance for the dye and cod removals 3experimental work 3.1. equipment the chemicals have been used in the present work were methylene orange (mo), sodium hydroxide (0.1m), hydrochloric acid (0.1m). the aqueous solutions were prepared by using distilled water. stock solution was prepared, which were diluted as per the requirements. the structure and properties of mo is shown in fig. 1. o. a. nashmi et al. / iraqi journal of chemical and petroleum engineering 21,2 (2020) 25 35 27 fig. 1. methylene orange structure and properties [41] the schematic diagram for the semibatch reactor of ozone micro bubble unit is shown in fig.2.the setup comprises a column reactor, an oxygen source, an ozone generator (shanghai enaly m&e; model: ozx05k) , and a gas distribution system(i.e. diffuser) to generate micro bubbles . as illustrated in the figure, oxygen with high-purity (> 98% by volume), was supplied to the ozone generator which was used to convert oxygen gas to ozone gas via the corona-discharge technique. the generation rates of ozone that applied in this work were dominated in the range of 0.498–0.83 mg/s depending on the recommendation of the manufacturer. the gas combination (i.e. oxygen and ozone) that released from the ozone generator was then entered to a flow meter in order to evaluate its flow rate before entering the microbubbles diffuser (point for tm diffuser) (riverforest corporation, usa, as mk –iii) in the semi-batch column reactor where the micro bubbles be generated. in the micro bubble generator, the dissolution of gas in water was reached by applying an oxygen flow rate of 1 l/min, so micro bubbles are continuously produced by the discharge of pressure. the experiments were made in an air-conditioned room where the temperature was maintained at 298 ±1 k. the initial concentration of mo in the aqueous solutions was 5ppm and the initial ph was 5.6, the ph of the solution be maintained by the use of 0.1m hcl and 0.1m naoh solutions. the samples from the reactor were collected initially every 1min and then after 7 min they were taken every 5min to measure their concentrations. nearly all of the experiments were carried out with an ozonation rate of 0.83 mg/s. (a) (b) fig. 2. schematic diagram and actual photo of the experimental set-up (a) schematic diagram of the experimental set-up, (b) actual photo of the experimental set-up 3.2. analytical method all aqueous solutions ph was measured by the use of a ph meter (isolab.). quantitative analysis of the mo dye concentration was made by an ultraviolet uv–visible spectrophotometer (model: cary-100 conc., varian, usa). the wavelength of mo dye was detected at 552 nm. 4results and discussion 4.1. effect of mo initial concentration dyes concentration in wastewater changed in a wide range. thus, it is essential to study the influence of mo initial concentration on its removal efficiency by ozone micro bubbles. the experiments were carried out using different concentration of mo (5, 10, 15, 20, and 25ppm) at room temperature. solution ph and the ozone generation rate were kept constant during these experiments at 5.6 and 0.83mg/s respectively and the results are presented in fig. 3. it can be seen from the results that the concentration profiles followed the same trend for all concentrations of mo applied in the current study. upon increasing the initial concentration of mo from 5ppm to 25ppm, the removal efficiency decreased from about 100% to 85% within 15 min of ozonation time, indicating that more mo is oxidized by ozone at lower initial concentration. this can be understood by considering that the reaction follows pseudofirst order kinetics. therefore, the reaction rate decreased when mo concentration increased and that was accepted with the earlier work of ayana et al. [32]. o. a. nashmi et al. / iraqi journal of chemical and petroleum engineering 21,2 (2020) 25 35 28 fig. 3. effect of the initial concentration mo on the removal efficiency (ph=5.6, ozone generation rate =0.83mg/sec) 4.2. effect of the initial ph of feed solution it is important to investigate the effect of the solution ph on the oxidation of methylene orange (mo) since ph of the aqueous medium controls both the mechanism and the rate of the ozonation process. the ions that present in the ozonation system (i.e. h + or oh ) possibly will enhance the free radicals production. hence, the ph of the aqueous medium plays a vital role in the decomposition of ozone into oh [33]. numerous literatures [34, 35, 36, and 37] have been proposed the mechanism of ozone decomposition in acidic and alkaline solutions and the recapitulated in the work of khuntia et al. [38]. for mo an ionic dye its removal efficiency was showed slight dependence on ph similar results were as well reported in the literature, for instance, the ozonation of 𝐶𝑁 − ions was studied by rice [39] and it was pointed out that ph had slight effect on cyanide ozonation to cyanate. in accordance with the mechanism predicted by staehelin and hoigne [31], 𝑂𝐻− ions act in response with dissolved ozone to generate · 𝑂2 − free radicals, and 𝐻 + ions promote · 𝑂2 − free radicals to convert into ho3· free radicals, which are in turn decomposed to ·oh free radicals [48]. both 𝐻+ and 𝑂𝐻− ions are needed for the production of 𝑂𝐻 free radicals. additionally, the mo dissociation constant (𝑝𝐾𝑎) was 3.4[40], and as a result mo will be in an ionic state when the ph state is higher or lower than this rate. an ionic structure of mo is more hydrophilic in solution and be able to degrade via dissolved ozone and ·oh free radicals [41]. the dealing by ozone mbs involves direct oxidation via ozone molecules and oxidation by ·oh radicals which were produced throughout ozone decomposition. mechanism of oxidation involves hydroxyl replacement on the benzene rings and cavity of the aromatic rings [42]. through the oxidation process, mo degradation proceeds throughout the cleavage of the azo group that attached the two aromatic rings [43], and by-products such as, p-xylene, toluene, 2,3,5-trimethyl hexane, and 4aminoazobenzene are consequently produced [41, 44]. the by-products can be more oxidized to smaller molecules such as carbon dioxide, water, and sulfates. as mo can also be oxidized by ozone directly, ozonation mbs illustrated efficient treatment in a variety of ph ranges, the ph range was taken as (5.6, 8.2, 9.3, 10.3, 11.2) to examine the effect of the media on the removal rate, the highest removal efficiency was observed at ph of 5.6. similar to these results were also reported by sevimli et al. [45], in which the solution ph showed an insignificant influence on ozone utilization. thus, in the current study, ph 5.6 was found to be the best possible condition for the treatment of methyl orange as shown in fig. 4. the solution ph profile with different initial ph was investigated and the results are plotted in fig.5. from this figure it can be seen that the extent of ph of the solution decreased with time for all initial ph solutions considered in this study, which is to be expected owing to the formation of organic acid intermediates during the oxidation of mo which is responsible for the lowering of the medium ph [40] fig. 4. the effect of ph with time on the removal efficiency of mo (25˚c, mo concentration =5mg/l, ozone generation rate= 0.83 mg/sec) fig. 5. change of ph with time of mo (25˚c, mo concentration =5mg/l, o3 rate= 0.83mg/sec) 4.3. effect of ozone generation rate in the liquid phase, the ozonation rate has a major effect on the mo dye oxidation rate. in the current work, the ozonation experiments were made with a range of ozone generation rates starting from 0.498 to 0.83 mg/s to examine the influence of ozonation rate in the micro bubbles on the removal rate of mo dye. o. a. nashmi et al. / iraqi journal of chemical and petroleum engineering 21,2 (2020) 25 35 29 results of the experimental work are shown in fig. 6 which shows that the rate of removal efficiency of mo increased with increasing the generation rate of ozone. the effect of the ozonation rate on the decolorization rate of mo is significant [41]. from fig. 6, it was obviously show when the generation rate of ozone increased from 0.498mg/sec to 0.83 mg/sec, the removal efficiency for mo increases from 69% to 100% through 20 min as seen in fig. 6. because this ionic (mo) dye removal can be occurred by direct reaction when the ozonation rate was high and by indirect reaction when the free oh radical was dominated. in addition, increasing the ozone generation rate causes an increase in the partial pressure of ozone in the gas mixture out come from the ozonator and this results in an augmentation in the ozonation rate in the aqueous phase, as predict by the henry’s law, so even at low ozonation rate the removal efficiency was 74% when the reaction still for 25 min. fig. 6. effect of ozonation rate on mo removal efficiency (ph=5.6, mo conc. =10mg/l) the change in the ph solution at different ozonation rates with time was also studied and the results are plotted in fig. 7. from the results presented in this figure, it is evident that with increasing ozonation rate, the drop in the solution ph increased with time and this is due to the increase in the ozone transfer from the gas phase to the liquid phase [24] which leads, in turn, to increase the decolorization rate and decrease the ph solution through time as observed in fig. 7. a similar result was reported by constap el et al. [46], and the main reason for that is related to the formation of organic acids and aldehyde. fig. 7. change of ph with ozonation rate at different time intervals (ph=5.6, mo conc.=5mg/l) fig. 8. change of ph with ozonation rate at different time intervals (ph =8.2, mo conc.=5mg/l) fig. 9. change of ph with ozonation rate at different time intervals ( ph= 9.3, mo conc.=5mg/l) fig. 10. change of ph with ozonation rate at different time intervals (ph =10.3, mo conc.=5mg/l) from fig. 7-fig. 10, its clearly observed that when the ozonation rate decrease the drop off ph of the dyes solution also decreased until the lowest ozonation rate its nearly remain constant ,and that because when the ozone concentration is low that enhancing the indirect reaction when hydroxyl radical is produced in addition to strong acids that resulting from ozonation process so that the ph of the solution remain approximately constant or un change [41, 46]. the rapid de-colorization of mo was also visible within 10 min for all the applied mo concentration which range between 5–25 mg/l. o. a. nashmi et al. / iraqi journal of chemical and petroleum engineering 21,2 (2020) 25 35 30 the spectral band changed (after ∼5 min) due to the destruction of the structure of mo by ozone as shown in fig. 11. fig. 11. mo samples before and after 20 min of ozonation by microbubbles (mo concentration =25mg/l, o3=0.83mg/s, ph =5.6 at room temperature) 4.4. estimation of ozone self-decomposition rate constant ozone mass transfer in the aqueous phase for nonreacting systems by micro bubbles had been reported previously in the literature by khuntia et al; (2013)[47]. in current study, the ozone self-decomposition rate constant is determined through kinetic studies on our semi batch reactor. the dissolved ozone concentration in water has been calculated as a function of time and continue until it was reached saturation, which referred to the ozone concentration steady state, [𝐶𝐴𝐿 ]ss. after that, the generation of ozone was stopped and the reduction in the ozone concentration in the reactor was determined during the experiment time as shown in fig.12. the time taken to achieve steady state ozone concentration decreased when the ph of the medium increased. ozone decomposition in water depends on the aqueous solution ph and it was followed a pseudo firstorder kinetics and that reported as well in [47-49]. the self-decomposition reaction rate of ozone equation can be written as follows [50, 51] − 𝑑[𝐶𝐴𝐿] 𝑑𝑡 = 𝑘𝑑[𝐶𝐴𝐿 ] (8) where: [𝐶𝐴𝐿 ] is the ozone concentration in the aqueous solution and kd is the rate constant of ozone selfdecomposition. equation (8) integrated with the boundary condition that at t = 0, [𝐶𝐴𝐿 ] = [𝐶𝐴𝐿 ]ss and this gives the following equation: 𝑙𝑛 [𝐶𝐴𝐿]𝑠𝑠 [𝐶𝐴𝐿] = 𝑘𝑑𝑡 (9) equation (9) predicts that kd would be the slope of a straight line passing through the origin and this line is a plot of ln [𝐶𝐴𝐿 ] ss/ [𝐶𝐴𝐿 ] versus time t, table 1 summarizes the experimental values of kd at various ph. table 1. the experimental values of kd at different ph. ph 5 7 9 𝒌𝒅 (𝐬 −𝟏) × 𝟏𝟎 2.5 3 3.9 fig. 12. concentration profiles of ozone during its selfdecomposition one of the parameters that have a significant effect on ozone decay is ph. therefore as to be aware of the influence of ph on ozone decay, a number of experiments were conducted at various ph values of 5, 7, and 9. fig. 13 illustrated the ph effect on the decay rate of ozone when the experiments were carried out in the absence of any dye. it was observed that at low ph the decay rate of is slow and it was increases when the ph increased. moreover, that’s means; the half-life time t1/2 of ozone was ph dependent, for that reason, any increase in the ph leads to a decrease in the t1/2. fig. 13. dissolved ozone concentration in water at different ph 4.5. estimation of volumetric mass transfer coefficient 𝑘𝐿𝑎 (s −1) the absorption of ozone start to increase gradually with time until it reaches to the saturation value 𝐶𝐴𝐿 ∗ . the results reveal that after 30 min at any ph value, the saturated concentration of ozone was reached. the saturated concentration of the ozone was (0.04, 0.025 and 0.018) mol/m 3 at ph of 9, 7 and 5 respectively as shown in fig. 13. o. a. nashmi et al. / iraqi journal of chemical and petroleum engineering 21,2 (2020) 25 35 31 the kinetic calculation will be performed at various ph values to investigate the influence of ph on the volumetric mass transfer coefficient for absorption processes. for ph= 9: k= 6.015 × 102s−1 and 𝑘𝐿𝑎=5.6259 × 102s−1 and figure.14 show the experimental and the theoretical data that obtained from the following equation [53]: 𝐶𝐴𝐿 = 𝑘𝑙𝑎 𝐾 𝐶𝐴𝐿 ∗ (1 −℮xp (−𝐾𝑡)) (10) where: (k = 𝑘𝐿𝑎 + 𝑘𝑑 ), 𝑘𝑑 was determined from a separate experimental study as shown in fig. 12 ; 𝐶𝐴𝐿 ∗ was determined from the fig. 13. fig. 14. the experimental and theoretical data at ph=9 for ph = 7, k=5.336 × 102s−1 and the value of 𝑘𝐿𝑎=5.0366 × 10 2s−1 and fig. 15 shows the experimental and theoretical data. fig. 15. the experimental and theoretical data at ph=7 for ph = 5 k =5.47 × 102s−1 and 𝑘𝐿𝑎=5.22 × 10 2s−1 and fig. 16 shows the experimental and theoretical data. fig. 16. the experimental theoretical data at ph=5 the result above shows the effect of ph value on the constant rate of absorption and decomposition of the ozone at different ph value. when the ph value increases to 9 the constant rate of absorption also increases. ph was take place as a vital parameter in ozone reaction pathway. molecular ozone oxidation have a tendency to dominate in an acidic conditions whereas, free-radical oxidation is dominated at higher ph. this owes to the generation of hydroxyl radicals (oh°) is improved in an alkaline condition. so, these radicals have an oxidation potential further more than ozone molecular [28], as shown from table 2 the kinetic and mass transfer parameters at various ph (at ozonation rate of 0.83 mg/s). table 2. values of the volumetric mass transfer at various ph and ozonation rate of 0.83mg/s ph 5 7 9 𝐤𝐋𝐚,( 𝐬 −𝟏) × 𝟏𝟎𝟐 5.22 5.0366 5.6259 the solubility and decomposition rate of ozone in water is affected by factors such as ph. the ph of the water is important because hydroxide ions effect ozone decomposition. the concentration of ozone in the solutions increases as alkalinity increases. 4.6. removal of chemical oxygen demand (cod) from mo aqueous solution results of the experiments were made and discussion of these results were obtained using methylene orange dye so as to evaluate ozonation process effect on the removal rate of cod as shown in fig. 16. o. a. nashmi et al. / iraqi journal of chemical and petroleum engineering 21,2 (2020) 25 35 32 fig. 17. removal of cod in mo aqueous solution (mo=100 mg/l, ph =5.6, at room temperature) in general, several organic chemicals such as dyes, biocides, ionic and non-ionic surfactants, carriers, sizing agents are contained in industrial wastewaters. as a result, it was difficult to establish the degradation rate for each organic compound present in wastewater individually. hence, some worldwide waste water parameters such as cod were used as an indication for the degradation kinetics of organic compounds by ozonation. for this purpose, experiments were carried out in order to assess the effect of ozonation process on the cod removal efficiency. fig. 17 shows the values of cod in solution after the ozonation process. as can be seen from figure .17 the removal rate of color was 5% within the first 10 min whereas, for the duration of the initial 30 min, the removal of color was relatively fast and its decolorization rate has increased with time. between 30th and 60th minutes these removal rates continue to increase rapidly and after 60th minutes a slowdown has been noticed. it is expected that the changes in the cod value for mo aqueous solution may be as a reason of the breakdown of azo bond (n=n-) in mo and construction of nitric acid via ozonation process, because the degradation of mo dye by ozone mbs was occurred as a result of two following steps. firstly, the decomposition of chromophore groups (-n=n-, -n-(ch3)2) step of mo by ozonation and the subsequent step is the breakdown of aromatic rings [32]. 5conclusion this study was paying attention on investigating the efficiency of using ozone micro bubbles for the oxidation of methylene orange dye (mo) from aqueous solutions. the data obtained from this work showed that this technique was very effective in removing mo from liquid medium. from the experimental work, it was found that acidic and alkaline condition enhances the separation efficiency of mo. removal efficiencies of 100% was obtained under conditions of ph 5.6 and ozone generation rate of 0.83mg/s the direct and indirect reaction of ozonation process was dominant during the separation of mo process. it was found also when generation rate of ozone increases, the concentration of dissolved ozone in the aqueous phase increased,which in turn improved mo oxidation rate. complete mineralization was achieved at ph value of 5.6 and ozonation rate of 0.83 mg/s. also, the oxidation of mo with ozone followed pseudo first-order kinetics which means that increasing the concentration of mo negatively affect its removal efficiency of the liquid solution. abbreviation mo: methylene orange ombs: ozone micro bubbles references [1] ali, i.; asim, m.; khan, t.a. low cost adsorbents for the removal of organic pollutants from wastewater. j. environ. manag. 2012, 113, 170–183. [2] ramakrishna, k. r., & viraraghavan, t. (1997). dye removal using low cost adsorbents. water science and technology, 36(2-3), 189–196. [3] oliver j. hao , hyunook kim & pen-chi chiang (2000) decolorization of wastewater, critical reviews in environmental science and technology, 30:4, 449-505. [4] m. a. hanoon and m. j. ahmed(2019). adsorption of methyl orange from wastewater by using biochar. iraqi journal of chemical and petroleum engineering, vol.20 no.3 (september 2019). [5] carmen, z., & daniel, s. (2012). textile organic dyes – characteristics, polluting effects and separation/elimination procedures from industrial effluents – a critical overview. organic pollutants ten years after the stockholm convention environmental and analytical update. [6] a. abbas najim and a. a. mohammed, “biosorption of methylene blue from aqueous solution using mixed algae”, ijcpe, vol. 19, no. 4, pp. 1-11, dec. 2018. [7] jones, k.c.; de voogt, p. persistent organic pollutants (pops): state of the science. environ. pollut. 1999, 100, 209–221. [8] liu, z.; kanjo, y.; mizutani, s. removal mechanisms for endocrine disrupting compounds (edcs) in wastewater treatmentphysical means, biodegradation, and chemical advanced oxidation: a review. sci. total environ. 2009, 407, 731–748. [9] ikehata, k.; gamal ei-din, m.; snyder, s.a. ozonation and advanced oxidation treatment of emerging organic pollutants in water and wastewater. ozone-sci. eng. 2008, 30, 21–26. [10] lefebvre, o.; moletta, r. treatment of organic pollution in industrial saline wastewater: a literature review. water res. 2006, 40, 3671–3682. [11] sun, l.; li, y.; li, a.m. treatment of actual chemical wastewater by a heterogeneous fenton process using natural pyrite. int. j. environ. res. public health 2015, 12, 13762–13778. https://www.sciencedirect.com/science/article/pii/s0301479712004367 https://www.sciencedirect.com/science/article/pii/s0301479712004367 https://www.sciencedirect.com/science/article/pii/s0301479712004367 https://www.ircwash.org/sites/default/files/341.0-97dy-15639.pdf https://www.ircwash.org/sites/default/files/341.0-97dy-15639.pdf https://www.ircwash.org/sites/default/files/341.0-97dy-15639.pdf https://www.tandfonline.com/doi/abs/10.1080/10643380091184237 https://www.tandfonline.com/doi/abs/10.1080/10643380091184237 https://www.tandfonline.com/doi/abs/10.1080/10643380091184237 https://www.tandfonline.com/doi/abs/10.1080/10643380091184237 https://doi.org/10.31699/ijcpe.2019.3.4 https://doi.org/10.31699/ijcpe.2019.3.4 https://doi.org/10.31699/ijcpe.2019.3.4 https://doi.org/10.31699/ijcpe.2019.3.4 http://www.flagshipdhaka.com/water-waste-water/ecr/pdf/22.pdf http://www.flagshipdhaka.com/water-waste-water/ecr/pdf/22.pdf http://www.flagshipdhaka.com/water-waste-water/ecr/pdf/22.pdf http://www.flagshipdhaka.com/water-waste-water/ecr/pdf/22.pdf http://www.flagshipdhaka.com/water-waste-water/ecr/pdf/22.pdf http://www.flagshipdhaka.com/water-waste-water/ecr/pdf/22.pdf https://doi.org/10.31699/ijcpe.2018.4.1 https://doi.org/10.31699/ijcpe.2018.4.1 https://doi.org/10.31699/ijcpe.2018.4.1 https://doi.org/10.31699/ijcpe.2018.4.1 https://www.sciencedirect.com/science/article/abs/pii/s0269749199000986 https://www.sciencedirect.com/science/article/abs/pii/s0269749199000986 https://www.sciencedirect.com/science/article/abs/pii/s0269749199000986 https://www.sciencedirect.com/science/article/pii/s0048969708008942 https://www.sciencedirect.com/science/article/pii/s0048969708008942 https://www.sciencedirect.com/science/article/pii/s0048969708008942 https://www.sciencedirect.com/science/article/pii/s0048969708008942 https://www.sciencedirect.com/science/article/pii/s0048969708008942 https://www.tandfonline.com/doi/abs/10.1080/01919510701728970 https://www.tandfonline.com/doi/abs/10.1080/01919510701728970 https://www.tandfonline.com/doi/abs/10.1080/01919510701728970 https://www.tandfonline.com/doi/abs/10.1080/01919510701728970 https://www.sciencedirect.com/science/article/abs/pii/s0043135406005082 https://www.sciencedirect.com/science/article/abs/pii/s0043135406005082 https://www.sciencedirect.com/science/article/abs/pii/s0043135406005082 https://www.mdpi.com/1660-4601/12/11/13762 https://www.mdpi.com/1660-4601/12/11/13762 https://www.mdpi.com/1660-4601/12/11/13762 https://www.mdpi.com/1660-4601/12/11/13762 o. a. nashmi et al. / iraqi journal of chemical and petroleum engineering 21,2 (2020) 25 35 33 [12] asghar, a.; raman, a.a.a.; daud, w.m.a.w. advanced oxidation processes for in-sit production of hydrogen peroxide/hydroxyl radicals for textile wastewater treatment: a review. j. clean. prod. 2015, 87, 826–838. [13] oturan, m.a.; aaron, j.j. advanced oxidation processes in water/wastewater treatment: principles and applications. a review. crit. rev. env. sci. technol. 2014, 44, 2577–2641. [14] llyas, h.; masih, l.; van der hoek, j.p. disinfection methods for swimming pool water: byproduct formation and control. water 2018, 10, 797. [15] gomes, j.; costa, r.; quinta-ferreira, r.m.; martins, r.c. application of ozonation for pharmaceuticals and personal care products removal from water. sci. total environ. 2017, 586, 265–283. [16] oller, i.; malato, s.; sánchez-pérez, j.a. combination of advanced oxidation processes and biological treatments for wastewater decontamination—a review. sci. total environ. 2011, 409, 4141–4166. [17] zhang, f., xi, j., huang, j.-j., hu, h.-y., 2013. effect of inlet ozone concentration on the performance of a micro-bubble ozonation system for inactivation of bacillus subtilis spores. sep. purif. technol. 114, 126e133. [18] seddon, j.r.t.; lohse, d.; ducker, w.a.; craig, v.s.j. a deliberation on nanobubbles at surfaces and in bulk. chemphyschem 2012, 13, 2179–2187. [19] li, h.; hu, l.; song, d.; lin, f. characteristics of micro-nano bubbles and potential application in groundwater bioremediation. water environ. res. 2014, 86, 844–851. [20] agarwal, a.; ng, w.j.; liu, y. principle and applications of microbubble and nanobubble technology for water treatment. chemosphere 2011, 84, 1175–1180. [21] hu, l.m.; xia, z.r. application of ozone micronano-bubbles to groundwater remediation. j. hazard. mater. 2018, 342, 446–453. [22] jabesa, a., & ghosh, p. (2016). removal of diethyl phthalate from water by ozone microbubbles in a pilot plant. journal of environmental management, 180, 476–484. [23] f.banat, s. al.-asheh, m. al.-rawashdeh, m. nusair, “photodegradation of methylene blue dye by uv/h2o2 and uv/acetone oxidation processes”, desalination, 181(2005)225. [24] chu w. and chi-wai m. (1999). quantitative prediction of direct and indirect dye ozonation kinetics. water res. 34 (12), 3153-3160. [25] yurteri, c., and gürol, m.d. (1988). ozone consumption in natural waters: effects of background organic matter, ph and carbonate species. ozone sci. eng., 10, 272282. [26] lopez-lopez, a., pic, j.s., debellefontaine, h. (2007). ozonation of azo dye in a semi-batch reactor: a determination of the molecular and radical contributions, chemosphere, 66(11), 2120-2126. [27] soares g.p., saloma o., orfao j.j.m., portela d., vieira a., pereira m.r., (2006), ozonation of textile effluents and dye solutions under continuous operation: influence of operating parameters. j. hazard. mater. b137, 16641673. [28] hoigne, j., bader, h., 1983. rate constants of reactions of ozone with organic and inorganic compounds in waterei: non-dissociating organic compounds. water res. 17 (2), 173-183. [29] park j.s., choi h., cho j. (2004). kinetic decomposition of ozone and parachlorobenzoic acid (p-cba) during catalytic ozonation. water res. 38(9), 2285-2292. [30] oyama, s.t. (2000). chemical and catalytic properties of ozone. catal. today, 42(3), 279-322. [31] staehelin, j. and hoigne, j. (1985). decomposition of ozone in water in the presence of organic solutes acting as promoters and inhibitors of radical chain reactions. environ. sci. technol., 19(12), 1206-1213. [32] ayana shimizu , yasuhiko takuma , shigeru kato , akihiro yamasaki, toshinori kojima , kohei urasaki , shigeo satokawa. degradation kinetics of azo dye by ozonation in water, j. fac. sci.tech., seikei univ. vol.50 no.2 (2013)pp.1-4. [33] beltran, f.j., 2004. ozone reaction kinetics for water and wastewater systems. lewis publishers, boca raton. [34] staehelin, j., buehler, r.e., hoigne, j., ozone decomposition in water studied by pulse radiolysis. 2. hydroxyl and hydrogen tetroxide (ho4) as chain intermediates. j. phys. chem. 88 (24), 5999-6004, 1984. [35] tomiyasu, h., fukutomi, h., gordon, g., kinetics and mechanism of ozone decomposition in basic aqueous solution. inorg. chem. 24 (19), 29622966, 1985. [36] gardoni, d., vailati, a., canziani, r., 2012. decay of ozone in water: a review. ozone sci. eng. 34 (4), 233-242. [37] sehested, k., corfitzen, h., holcman, j., fischer, c.h., hart, e.j., 1991. the primary reaction in the decomposition of ozone in acidic aqueous solutions. environ. sci. technol. 25 (9), 1589-1596. [38] khuntia, s., majumder, s.k., ghosh, p., quantitative prediction of generation of hydroxyl radicals from ozone microbubbles. chem. eng. res. des. 98, 231-239, 2015. [39] rice r. g., "applications of ozone for industrial wastewater treatment": a review. ozone sci. & eng. 18, 477-515, 1996. [40] grabowski, l. r., veldhuizen, e. m. van, pemen, a. j. m., & rutgers, w. r. "breakdown of methylene blue and methyl orange by pulsed corona discharge". plasma sources science and technology, 16(2), 226–232, 2007. https://www.sciencedirect.com/science/article/abs/pii/s0959652614009408 https://www.sciencedirect.com/science/article/abs/pii/s0959652614009408 https://www.sciencedirect.com/science/article/abs/pii/s0959652614009408 https://www.sciencedirect.com/science/article/abs/pii/s0959652614009408 https://www.sciencedirect.com/science/article/abs/pii/s0959652614009408 https://www.tandfonline.com/doi/abs/10.1080/10643389.2013.829765 https://www.tandfonline.com/doi/abs/10.1080/10643389.2013.829765 https://www.tandfonline.com/doi/abs/10.1080/10643389.2013.829765 https://www.tandfonline.com/doi/abs/10.1080/10643389.2013.829765 https://www.mdpi.com/2073-4441/10/6/797 https://www.mdpi.com/2073-4441/10/6/797 https://www.mdpi.com/2073-4441/10/6/797 https://www.mdpi.com/2073-4441/10/6/797 https://www.sciencedirect.com/science/article/pii/s0048969717302334 https://www.sciencedirect.com/science/article/pii/s0048969717302334 https://www.sciencedirect.com/science/article/pii/s0048969717302334 https://www.sciencedirect.com/science/article/pii/s0048969717302334 https://www.sciencedirect.com/science/article/pii/s0048969710009344 https://www.sciencedirect.com/science/article/pii/s0048969710009344 https://www.sciencedirect.com/science/article/pii/s0048969710009344 https://www.sciencedirect.com/science/article/pii/s0048969710009344 https://www.sciencedirect.com/science/article/pii/s0048969710009344 https://www.sciencedirect.com/science/article/pii/s138358661300258x https://www.sciencedirect.com/science/article/pii/s138358661300258x https://www.sciencedirect.com/science/article/pii/s138358661300258x https://www.sciencedirect.com/science/article/pii/s138358661300258x https://www.sciencedirect.com/science/article/pii/s138358661300258x https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/cphc.201100900 https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/cphc.201100900 https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/cphc.201100900 https://onlinelibrary.wiley.com/doi/abs/10.2175/106143014x14062131177953 https://onlinelibrary.wiley.com/doi/abs/10.2175/106143014x14062131177953 https://onlinelibrary.wiley.com/doi/abs/10.2175/106143014x14062131177953 https://onlinelibrary.wiley.com/doi/abs/10.2175/106143014x14062131177953 https://www.sciencedirect.com/science/article/abs/pii/s0045653511006242 https://www.sciencedirect.com/science/article/abs/pii/s0045653511006242 https://www.sciencedirect.com/science/article/abs/pii/s0045653511006242 https://www.sciencedirect.com/science/article/abs/pii/s0045653511006242 https://www.sciencedirect.com/science/article/pii/s0304389417306222 https://www.sciencedirect.com/science/article/pii/s0304389417306222 https://www.sciencedirect.com/science/article/pii/s0304389417306222 https://www.sciencedirect.com/science/article/pii/s0301479716303279 https://www.sciencedirect.com/science/article/pii/s0301479716303279 https://www.sciencedirect.com/science/article/pii/s0301479716303279 https://www.sciencedirect.com/science/article/pii/s0301479716303279 https://www.sciencedirect.com/science/article/abs/pii/s0011916405003930 https://www.sciencedirect.com/science/article/abs/pii/s0011916405003930 https://www.sciencedirect.com/science/article/abs/pii/s0011916405003930 https://www.sciencedirect.com/science/article/abs/pii/s0011916405003930 https://www.sciencedirect.com/science/article/abs/pii/s0043135400000439 https://www.sciencedirect.com/science/article/abs/pii/s0043135400000439 https://www.sciencedirect.com/science/article/abs/pii/s0043135400000439 https://www.tandfonline.com/doi/abs/10.1080/01919518808552258 https://www.tandfonline.com/doi/abs/10.1080/01919518808552258 https://www.tandfonline.com/doi/abs/10.1080/01919518808552258 https://www.tandfonline.com/doi/abs/10.1080/01919518808552258 https://www.sciencedirect.com/science/article/abs/pii/s0045653506012355 https://www.sciencedirect.com/science/article/abs/pii/s0045653506012355 https://www.sciencedirect.com/science/article/abs/pii/s0045653506012355 https://www.sciencedirect.com/science/article/abs/pii/s0045653506012355 https://www.sciencedirect.com/science/article/abs/pii/s0304389406004511 https://www.sciencedirect.com/science/article/abs/pii/s0304389406004511 https://www.sciencedirect.com/science/article/abs/pii/s0304389406004511 https://www.sciencedirect.com/science/article/abs/pii/s0304389406004511 https://www.sciencedirect.com/science/article/abs/pii/s0304389406004511 https://www.sciencedirect.com/science/article/abs/pii/0043135483900982 https://www.sciencedirect.com/science/article/abs/pii/0043135483900982 https://www.sciencedirect.com/science/article/abs/pii/0043135483900982 https://www.sciencedirect.com/science/article/abs/pii/0043135483900982 https://www.sciencedirect.com/science/article/abs/pii/s0043135404000181 https://www.sciencedirect.com/science/article/abs/pii/s0043135404000181 https://www.sciencedirect.com/science/article/abs/pii/s0043135404000181 https://www.sciencedirect.com/science/article/abs/pii/s0043135404000181 https://www.tandfonline.com/doi/abs/10.1081/cr-100100263?journalcode=lctr20 https://www.tandfonline.com/doi/abs/10.1081/cr-100100263?journalcode=lctr20 https://pubs.acs.org/doi/pdf/10.1021/es00142a012 https://pubs.acs.org/doi/pdf/10.1021/es00142a012 https://pubs.acs.org/doi/pdf/10.1021/es00142a012 https://pubs.acs.org/doi/pdf/10.1021/es00142a012 https://pubs.acs.org/doi/pdf/10.1021/es00142a012 http://54.64.109.41/dspace/handle/10928/447 http://54.64.109.41/dspace/handle/10928/447 http://54.64.109.41/dspace/handle/10928/447 http://54.64.109.41/dspace/handle/10928/447 http://54.64.109.41/dspace/handle/10928/447 http://54.64.109.41/dspace/handle/10928/447 https://books.google.iq/books?hl=en&lr=&id=i9igszemey0c&oi=fnd&pg=pp1&dq=%5b33%5d%09beltran,+f.j.,+2004.+ozone+reaction+kinetics+for+water+and+wastewater+systems.+lewis+publishers,+boca+raton.+&ots=r-q6aqhes9&sig=c1ogwavsicfgtb1peb9zgyeg0ci&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=i9igszemey0c&oi=fnd&pg=pp1&dq=%5b33%5d%09beltran,+f.j.,+2004.+ozone+reaction+kinetics+for+water+and+wastewater+systems.+lewis+publishers,+boca+raton.+&ots=r-q6aqhes9&sig=c1ogwavsicfgtb1peb9zgyeg0ci&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=i9igszemey0c&oi=fnd&pg=pp1&dq=%5b33%5d%09beltran,+f.j.,+2004.+ozone+reaction+kinetics+for+water+and+wastewater+systems.+lewis+publishers,+boca+raton.+&ots=r-q6aqhes9&sig=c1ogwavsicfgtb1peb9zgyeg0ci&redir_esc=y#v=onepage&q&f=false https://pubs.acs.org/doi/pdf/10.1021/j150668a051 https://pubs.acs.org/doi/pdf/10.1021/j150668a051 https://pubs.acs.org/doi/pdf/10.1021/j150668a051 https://pubs.acs.org/doi/pdf/10.1021/j150668a051 https://pubs.acs.org/doi/pdf/10.1021/j150668a051 https://pubs.acs.org/doi/pdf/10.1021/ic00213a018 https://pubs.acs.org/doi/pdf/10.1021/ic00213a018 https://pubs.acs.org/doi/pdf/10.1021/ic00213a018 https://pubs.acs.org/doi/pdf/10.1021/ic00213a018 https://www.tandfonline.com/doi/abs/10.1080/01919512.2012.686354 https://www.tandfonline.com/doi/abs/10.1080/01919512.2012.686354 https://www.tandfonline.com/doi/abs/10.1080/01919512.2012.686354 https://pubs.acs.org/doi/pdf/10.1021/es00021a010 https://pubs.acs.org/doi/pdf/10.1021/es00021a010 https://pubs.acs.org/doi/pdf/10.1021/es00021a010 https://pubs.acs.org/doi/pdf/10.1021/es00021a010 https://www.sciencedirect.com/science/article/abs/pii/s0263876215001070 https://www.sciencedirect.com/science/article/abs/pii/s0263876215001070 https://www.sciencedirect.com/science/article/abs/pii/s0263876215001070 https://www.sciencedirect.com/science/article/abs/pii/s0263876215001070 https://www.tandfonline.com/doi/abs/10.1080/01919512.1997.10382859 https://www.tandfonline.com/doi/abs/10.1080/01919512.1997.10382859 https://www.tandfonline.com/doi/abs/10.1080/01919512.1997.10382859 https://iopscience.iop.org/article/10.1088/0963-0252/16/2/003/meta https://iopscience.iop.org/article/10.1088/0963-0252/16/2/003/meta https://iopscience.iop.org/article/10.1088/0963-0252/16/2/003/meta https://iopscience.iop.org/article/10.1088/0963-0252/16/2/003/meta https://iopscience.iop.org/article/10.1088/0963-0252/16/2/003/meta o. a. nashmi et al. / iraqi journal of chemical and petroleum engineering 21,2 (2020) 25 35 34 [41] chen, l.c. effects of factors and interacted factors on the optimal decolorization process of methyl orange by ozone. water res. 2000, 34, 974– 982. [42] petrella, a.; mascolo, g.; murgolo, s.; petruzzelli, v.; ranieri, e.; spasiano, d.; petruzzelli, d. photocatalytic oxidation of organic micropollutants: pilot plant investigation and mechanistic aspects of the degradation reaction. chem. eng. commun. 2016, 203, 1298–1307. [43] devi, l.g.; kumar, s.g.; reddy, k.m.; munikrishnappa, c. photo degradation of methyl orange an azo dye by advanced fenton process using zero valent metallic iron: influence of various reaction parameters and its degradation mechanism. j. hazard. mater. 2009, 164, 459–467. [44] ge, d.m.; zeng, z.q.; arowo, m.; zou, h.k.; chen, j.f.; shao, l. degradation of methyl orange by ozone in the presence of ferrous and persulfate ions in a rotating packed bed. chemosphere 2016, 146, 413– 418. [45] sevimli, m.f.; sarikaya, h.z. ozone treatment of textile effluents and dyes: effect of applied ozone dose, ph and dye concentration. j. chem. technol. biotechnol. 2002, 77, 842–850. [46] constapel, m.; schellenträger, m.; marzinkowski, j.m.; gäb, s. degradation of reactive dyes in wastewater from the textile industry by ozone: analysis of the products by accurate masses. water. res. 2009, 43, 733–743. [47] khuntia s, majumder sk, ghosh p. removal of ammonia from water by ozone microbubbles. ind eng chem res. 2013;52:318–326. [48] sotelo jl, beltrán fj, benitez fj, et al. henry’s law constant for the ozone–water system. water res. 1989;23:1239– 1246. [49] sotelo jl, beltran fj, benitez fj, et al. ozone decomposition in water: kinetic study. ind eng chem res. 1987;26:39–43. [50] gao m-t, hirata m, takanashi h, et al. ozone mass transfer in a new gas–liquid contactor – karman contactor. sep purif technol. 2005;42:145–149. [51] kukuzaki m, fujimoto k, kai s, et al. ozone mass transfer in an ozone–water contacting process with shirasu porous glass (spg) membranes – a comparative study of hydrophilic and hydrophobic membranes. sep purif technol. 2010;72:347–356. [52] yc hsu, ty chen, jh chen and c. w. lay, ozone transfer into water in a gas-inducing reactor. ind eng chem res. 2002; 41:120–127. [53] grima, n. m. m. kinetic and mass transfer studies of ozone degradation of organics in liquid/gasozone and liquid/solid-ozone systems. diss. university of bradford, 2009. https://www.sciencedirect.com/science/article/abs/pii/s0043135499001888 https://www.sciencedirect.com/science/article/abs/pii/s0043135499001888 https://www.sciencedirect.com/science/article/abs/pii/s0043135499001888 https://www.sciencedirect.com/science/article/abs/pii/s0043135499001888 https://www.tandfonline.com/doi/abs/10.1080/00986445.2016.1188292 https://www.tandfonline.com/doi/abs/10.1080/00986445.2016.1188292 https://www.tandfonline.com/doi/abs/10.1080/00986445.2016.1188292 https://www.tandfonline.com/doi/abs/10.1080/00986445.2016.1188292 https://www.tandfonline.com/doi/abs/10.1080/00986445.2016.1188292 https://www.tandfonline.com/doi/abs/10.1080/00986445.2016.1188292 https://www.sciencedirect.com/science/article/abs/pii/s0304389408012211 https://www.sciencedirect.com/science/article/abs/pii/s0304389408012211 https://www.sciencedirect.com/science/article/abs/pii/s0304389408012211 https://www.sciencedirect.com/science/article/abs/pii/s0304389408012211 https://www.sciencedirect.com/science/article/abs/pii/s0304389408012211 https://www.sciencedirect.com/science/article/abs/pii/s0304389408012211 https://www.sciencedirect.com/science/article/abs/pii/s0045653515305129 https://www.sciencedirect.com/science/article/abs/pii/s0045653515305129 https://www.sciencedirect.com/science/article/abs/pii/s0045653515305129 https://www.sciencedirect.com/science/article/abs/pii/s0045653515305129 https://www.sciencedirect.com/science/article/abs/pii/s0045653515305129 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.644 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.644 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.644 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.644 https://www.sciencedirect.com/science/article/abs/pii/s0043135408005368 https://www.sciencedirect.com/science/article/abs/pii/s0043135408005368 https://www.sciencedirect.com/science/article/abs/pii/s0043135408005368 https://www.sciencedirect.com/science/article/abs/pii/s0043135408005368 https://www.sciencedirect.com/science/article/abs/pii/s0043135408005368 https://pubs.acs.org/doi/abs/10.1021/ie302212p https://pubs.acs.org/doi/abs/10.1021/ie302212p https://pubs.acs.org/doi/abs/10.1021/ie302212p https://www.sciencedirect.com/science/article/abs/pii/0043135489901863 https://www.sciencedirect.com/science/article/abs/pii/0043135489901863 https://www.sciencedirect.com/science/article/abs/pii/0043135489901863 https://pubs.acs.org/doi/pdf/10.1021/ie00061a008 https://pubs.acs.org/doi/pdf/10.1021/ie00061a008 https://pubs.acs.org/doi/pdf/10.1021/ie00061a008 https://www.sciencedirect.com/science/article/pii/s138358660400187x https://www.sciencedirect.com/science/article/pii/s138358660400187x https://www.sciencedirect.com/science/article/pii/s138358660400187x https://www.sciencedirect.com/science/article/pii/s1383586610001024 https://www.sciencedirect.com/science/article/pii/s1383586610001024 https://www.sciencedirect.com/science/article/pii/s1383586610001024 https://www.sciencedirect.com/science/article/pii/s1383586610001024 https://www.sciencedirect.com/science/article/pii/s1383586610001024 https://pubs.acs.org/doi/abs/10.1021/ie0101341 https://pubs.acs.org/doi/abs/10.1021/ie0101341 https://pubs.acs.org/doi/abs/10.1021/ie0101341 https://bradscholars.brad.ac.uk/handle/10454/3351 https://bradscholars.brad.ac.uk/handle/10454/3351 https://bradscholars.brad.ac.uk/handle/10454/3351 https://bradscholars.brad.ac.uk/handle/10454/3351 o. a. nashmi et al. / iraqi journal of chemical and petroleum engineering 21,2 (2020) 25 35 35 دراسة تأثير استخدام فقاعات االوزون الصغيرة في معالجة المياه الملوثة بصبغة المثيلين البرتقالي 2و ندى نعوم عبدالرزاق 1احمد عبد محمد, 1عال عبد الكاظم نشمي جامعة بغداد/ كلية الهندسة / قسم هندسة البيئة1 جامعة بغداد/ كلية الهندسة / قسم الهندسة الكيمياوية2 الصةالخ يبحث هذا العمل في إزالة صبغة الميثيلين البرتقالي من الماء باستخدام فقاعات األوزون الصغيرة. تم إجراء تجارب في ظل ظروف تفاعل مختلفة لفحص آثار التركيز األولي لصبغة المثيلين البرتقالي ، ودرجة الحموضة برتقالي بشكل فعال بواسطة فقاعات األوزون. أظهرت في الوسط ومعدل توليد األوزون. تمت إزالة المثيلين ال النتائج أن إزالة بواسطة فقاعات األوزون كانت عالية جًدا في الوسط الحمضي والقلوي وعند زيادة معدل توليد 15٪ خالل 100إلى 75ملغم / ثانية ، زادت كفاءة اإلزالة بشكل كبير من 0.83إلى 0.498األوزون من ل تفاعل األكسدة نموذًجا حركًيا من الدرجة األولى. أظهرت النتائج أن فقاعات األوزون تكون دقيقة. يتبع معد فعالة من حيث انخفاض تركيز الصبغة وازالتها الكلية. المثيلين البرتقالي, فقاعات االوزون الصغيرة, معدل تولد االوزون, كفاءة االزالة الكلمات الدالة: iraqi journal of chemical and petroleum engineering vol.14 no.4 (december 2013) 7179 issn: 1997-4884 concentration of orange juice using forward osmosis membrane process khalid w. hameed biochemical engineering departmental-khwarizmi college of engineeringuniversity of baghdad abstract forward osmosis (fo) process was applied to concentrate the orange juice. fo relies on the driving force generating from osmotic pressure difference that result from concentration difference between the draw solution (ds) and orange juice as feed solution (fs). this driving force makes the water to transport from orange juice across a semi-permeable membrane to the ds without any energy applied. thermal and pressure-driven dewatering methods are widely used, but they are prohibitively energy intensive and hence, expensive. effects of various operating conditions on flux have been investigated. four types of salts were used in the ds, (nacl, cacl2, kcl, and mgso4) as osmotic agent and the experiments were performed at the concentration of the salts in the ds ranged (3.5 – 20% by wt), the temperature of ds ranged (20 – 50 o c), and the flow rate of the fs and ds ranged (1 – 4 lit/min). it was observed that the optimum operating conditions are: concentration of salt = 20% by wt for cacl2, temperature of ds = 50 o c, and the flow rate of fs = 4 lit/min where at these conditions the maximum flux was obtained equal to 13.2 lit/m 2 .h or the total volume of the water transferred from the juice (during 3 hours and membrane area of 0.0135 m 2 ) was 0.535 lit. nacl performed much higher efficiency as osmotic agent than the others salts up to the concentration of 15.2%, but after 15.2% the cacl2 was the best. key words: forward osmosis, reverse osmosis, fruit juice, osmotic pressure, draw solution. introduction membrane separation processes have become one of the emerging technologies in the last few decades especially in the separation technology field. they offer a number of advantages over conventional separation methods in a wide variety of applications such as distillation and evaporation. membrane processes can be easily scaled up due to their compact and modular design; they are able to transfer specific components selectively; they are energy efficient systems operating under moderate temperature conditions ensuring gentle product treatment [1]. osmosis is the transport of water across a selectively permeable membrane from a region of higher water chemical potential to a region of lower water chemical potential. it is driven by a difference in solute concentrations across the membrane iraqi journal of chemical and petroleum engineering university of baghdad college of engineering concentration of orange juice using forward osmosis membrane process 72 ijcpe vol.14 no.4 (december 2013) -available online at: www.iasj.net that allows passage of water, but rejects most solute molecules or ions [2]. water molecules will therefore move from one solution to another to achieve maximum mixing, i.e. equilibrium. thermodynamically, the strength of this mixing tendency is measured by the solution’s “osmotic potential,” or “osmotic pressure.” the osmotic potential is high for concentrated solutions and low for dilute solutions, and is roughly proportional to the molar concentration of dissolved species. osmotic pressure is the pressure that must be applied to a solution to prevent a net transfer of water into the solution across a semipermeable membrane [3]. by applying a pressure in excess of the osmotic pressure, pure water flows from the high solute concentration side through a membrane to the low solute concentration side and thus, the separation of water from the solution is achieved. this is the reverse of the normal osmosis process and termed as reverse osmosis (ro) [4, 5]. in wastewater treatment applications where the solvent is usually water and the solutes are the contaminants, the semi-permeable membrane allows the flux of water across the membrane but rejects contaminates. in such a system the wastewater, or feed, is passed on one side of the membrane and an osmotic agent (oa), such as salt water, is passed on the other. the oa can use any solute as long as it can produce an osmotic pressure that is higher than that of the feed and the solute used is well rejected by the membrane [6]. forward osmosis (fo) is emerging membrane separations technologies that have the potential to be innovative, sustainable, and affordable alternatives to reverse osmosis (ro) and electrodialysis reversal (edr) because of its ability to utilize the green energy available in natural systems [7]. the term forward osmosis is used to refer to normal osmotic processes is that will occur on its own, without any form of external pressure or push. our system adapts the fo theory and the advantages include:  elimination of external pressure  reduce cost by eliminating large pressure pumps and pressure exchanger systems  pressure generated in draw solution can be utilized in place of external pressure  supports the objective of smallscale power generation  availability of fo membranes that can be used to develop pro situations [8]. compared to ro, fo systems and the principle of osmotic pressure have a wide range of applications in the areas of wastewater treatment and water purification systems; seawater desalination and brackish water processes; concentration of solutions of food products, pharmaceutical solutions and chemical streams; and power generation [9, 10, 11]. traditionally, orange juice has been concentrated using a thermal process. such a process results in a loss of flavor top notes, color degradation, and a cooked taste. the citrus industry compensates for the product degradation through essence recovery, careful process control and blending to produce a good quality concentrate which, although readily distinguishable from fresh juice, has received broad consumer acceptance. the membrane process was designed to produce a concentrate juice with fresh juice flavor and commercial levels of stability [12]. eq. (1) shows the relationship between water flux across the membrane and both the hydrostatic and osmotic pressure differentials across the same membrane [13]. this equation is stated in the form most relevant to ro as follows: khalid w. hameed -available online at: www.iasj.net ijcpe vol.14 no.4 (december 2013) 73 fw = ac (∆p ∆π) …(1) where: fw = total water flux across the membrane (lit/m 2 .h) ac = membrane flux resistance constant (lit/m 2 . h.kpa) ∆p = hydrostatic pressure (kpa) ∆π = opposing osmotic pressure potential (kpa) which is equal to the difference between osmotic pressure of the draw solution and the feed solution in fo, the hydrostatic pressure supplied is zero and the same governing equation can be rearranged to eq. (2): fw = ac ∆π …(2) as a result of eq. (2) it can be seen that the membrane can be configured such that no hydrostatic pressure exists across the membrane and thus no pressure housing and/or support is required. this allows the membranes to operate in soft bags packed within water walls. in most cases some hydrostatic pressure is still present as a result of the act of supplying the membrane with a flow of liquid. this flow is required for both sides of the membrane and should be near to balanced (i.e. δp still zero across the membrane). in this situation the hydrostatic pressure could be in either the forward or opposing direction relative to the intended water flux direction, but in either case will be negligible in comparison to the osmotic pressures [14]. ac dependent on such membrane characteristics as membrane thickness, partition (sorption) coefficient of water into the membrane, and diffusivity of water within the polymer membrane phase [15]. the aim of the present work is to concentrate the orange juice by low cost method and retain the juice with its properties compared with the other methods such as reverse osmosis (high pressure required) or evaporation (caused loss of some properties of the juice such as its vitamins, flavor, color degradation …etc). in this research cellulose triacetate membrane was proposed for forward osmosis, fresh orange juice as feed solution (fs), and salt solution (sodium chloride, potassium chloride, calcium chloride, or magnesium sulfate) as draw solution (ds). the parameters studied were: concentration of salt in ds in the range of (3.5 – 20% by weight), temperature of ds in the range of (20 – 50 o c), and volumetric flow rate of ds and fs in the range of (1 – 4 lit/min) were studied on the effect of flux of water from fs to ds. experimental work 1. materials orange juice: the orange juice (feed solution) was obtained from fresh natural orange of local market, then the juice was filtered using filter paper to remove suspended solids, fiber, coarse pulp and pieces of orange. draw solution: the concentrated solution on the permeate side of the membrane is the source of the driving force in the fo process. the draw solution was prepared by smelting one of the following salts in the distilled water: sodium chloride (nacl), calcium chloride (cacl2), potassium chloride (kcl), or magnesium sulfate (mgso4). pumps: two pumps were used. each of 150720 gal/h, 11.4-54.6 lit/min. one used to the draw solution and the other used to the feed solution. membrane: cellulose triacetate (cta) sheet membrane (hydration technology inc. albany, or) have been used in the forward osmosis (fo) process. concentration of orange juice using forward osmosis membrane process 74 ijcpe vol.14 no.4 (december 2013) -available online at: www.iasj.net refractometer: digital refractometer was used to measure the sucrose content in the orange juice. it is calibrated by depending on the literature given by randle [16]. conductivity meter: digital conductivity meter was used to measure the conductivity of permeate solution. 2. experimental procedure the experiments were run on a bench-scale laboratory system. a schematic diagram is presented in fig. (1). the separation cell of membrane unit was built of two rectangular channels with the dimensions 15 cm long×9 cm wide×2 cm deep (the area of membrane = 0.0135 m 2 ) on both sides of the membrane. the volume of draw solution (ds) is 51 lit (in order to its osmotic pressure does not affected significantly with water transferred and then the change in flux with time will be small) and the volume of feed solution (fs) is 1 lit and they were run in a closed loop. the fs flows on the active layer of the membrane. in order to increase the mass transport on both sides of the membrane, mesh spacers made of polypropylene were inserted within both channels; also these mesh support the membrane and protect it from deformation. the temperature of both solutions was controlled using heating coil holding thermostat, and the volumetric flow rate of both solutions was controlled using rotameter. the pressures have kept on the fs side about 1.1 bar and on the ds side about 1.05 bar using gauge pressures mounted on above the box which contain the membrane as shown in fig. (1). 1 orange juice vessel 6 draw solution vessel 2 valve 7 by-pass flow 3 pump 8 recycle flow 4 rotameter 9 heating coil with thermostat 5 box contained the membrane 10 gauge pressure fig. 1, schematic diagram of the laboratory scale forward osmosis membrane unit system the time of experiment was three hours. water flux (permeate) into the ds was measured by the elevation in the ds volume during a selected period of time and compare with the reduction in the fs volume for checking where the vessels of the ds and fs are graduated and calibrated accurately with volume. dividing the water transferred by the area of membrane per time gives the flux in (l/m 2 .h). after each experiment, fs return to its original volume by adding the distilled water 4 3 8 6 8 7 2 1 5 9 10 khalid w. hameed -available online at: www.iasj.net ijcpe vol.14 no.4 (december 2013) 75 instead of the water lost and then reused again for three another experiment, after that fs (orange juice) is eliminated and new juice is used. ds also is return to its original concentration by adding a suitable amount of salt and checking its concentration using conductivity meter. also the fouled membrane is backwashed using salt solution in the juice circuit and fresh water in the ds circuit and operate for 15 min then washed for 30 min by circulating using ro water in each side. results and discussion 1. effect of draw solution concentration fig. (2) shows the effect of draw solution (ds) concentration on the flux of water through the membrane for four types of salts (nacl, cacl2, kcl, and mgso4). the experiments were conducted at the same conditions (temperature of feed and draw solution are 20 o c, and volumetric flow rate of feed and draw solution are 1 lit/min). as shown in fig. (2) the flux of water increases with increasing of salt concentration and the sodium chloride salt (nacl) has the more osmotic pressure than the other salts up to 15.2% by wt, after this concentration the calcium chloride salt (cacl2) exhibits more osmotic pressure and then more flux than the other salts. also magnesium sulfate (mgso4) has less osmotic pressure than the other salts, where before concentration of 7.4% gave negative flux (from draw solution to feed solution). the high osmotic pressure is obtained when the osmotic agent is highly soluble in water and has low molecular weight [5], and since nacl has lower molecular weight (58.5) and higher solubility (357 g/lit at 20 o c) than the other salts [17] it gave more osmotic pressure and then more flux than the others salts. nevertheless cacl2 (its molecular weight = 111 and its maximum solubility at 20 o c = 294g/lit [17]) gave osmotic pressure greater than nacl after concentration of 15.2%. based on eq. (2), the increase in flux should be linear with the osmotic pressure difference. fig. (2) however, shows a non-linear phenomenon, especially at higher driving forces. this phenomenon is attributed to internal concentration polarization, most likely due to microporosity at the membrane permeate side. fig. 2, effect of ds concentration on the flux of water at temp of fs and ds = 20 o c, flowrate of fs and ds = 1 lit/min 2. temperature effect fig. (3) shows the effect of temperature of draw solution (ds) on the osmotic pressure difference between the fs and ds and then on the flux of water. the experiments of the fig. (3) are achieved at the concentration of ds is 10% by wt, temperature of fs is 20 o c, and flow rate of fs and ds are 1 lit/min. the results in fig. (3) indicate that with increasing temperature of ds leads to increase the flux of water from fs to ds through membrane because of the viscosity decreases with increasing temperature which increases the diffusion rate of water through the membrane and thus, its water permeability coefficient and lead to concentration wt% f lu x ( li t/ m 2 h ) -1 1 3 5 7 9 11 13 2 6 10 14 18 22 nacl cacl 2 kcl mgso 4 concentration of orange juice using forward osmosis membrane process 76 ijcpe vol.14 no.4 (december 2013) -available online at: www.iasj.net increase of the osmotic pressure of the ds and then increase the flux of the water. an increased diffusion coefficient for the ds will increase the mass transfer coefficient, reducing the impact of the external concentration polarization (ecp) modulus. the effect is similar for the internal concentration polarization (icp) modulus, where an increased diffusion coefficient reduces solute resistivity. however, since both the ecp and icp moduli are exponential functions of the permeate water flux as well, the temperature effect on these phenomena will be lessened, as an increase in the water permeability coefficient of the membrane will increase flux. the viscosity of a solution is a measure of the fluid's resistance to flow or deformation [18]. also the osmotic pressure of the solution increased with increasing temperature according to the van’t hoff equation [5, 19]: π = irct …(3) where: π = osmotic pressure (kpa) i = dissociation factor (van't hoff factor) r = gas constant (8.314 kj/kmol.k) c = molar concentration (kmol/m 3 ) t = absolute temperature (k) for three salts (nacl, cacl2, and kcl) with increasing the temperature of ds gave slight increasing in water flux, while for mgso4 salt with increasing the temperature of ds gave slight decreasing in water flux. fig. (4) and (5) show the effect of concentration of nacl and cacl2 respectively as osmotic agent (oa) on the flux of water through membrane at different temperatures. again, by increasing the concentration of oa the flux of water increases and also increases with increasing the temperature of ds as shown in fig. (3). from fig. (3), (4), and (5) it can be seen that the temperature plays a minor role in osmosis driven processes compared with the concentration of the ds. fig. 3, effect of temperature of ds on the flux of water at concentration of salt in ds = 10%, flow rate of fs and ds = 1 lit/min and at temperature of fs = 20 o c fig. 4, effect of concentration of nacl on the flux of water at different temperature of ds and at temp of feed = 20 o c, flow rate of feed and ds = 1 lit/min fig.5 effect of concentration of cacl2 on the flux of water at different temperature of ds, temp of fs = 20 o c, flow rate of feed and ds = 1 lit/min temperature of ds o c f lu x , li t/ m 2 h -0.5 0.5 1.5 2.5 3.5 4.5 15 20 25 30 35 40 45 50 55 nacl kcl cacl 2 mgso 4 concentration wt% f lu x ( li t/ m 2 h ) -1 1 3 5 7 9 11 13 2 6 10 14 18 22 t =20 o c t = 30 o c t = 40 o c t = 50 o c concentration wt% f lu x ( li t/ m 2 h ) 0 2 4 6 8 10 12 14 2 6 10 14 18 22 t = 20 o c t = 30 o c t = 40 o c t = 50 o c khalid w. hameed -available online at: www.iasj.net ijcpe vol.14 no.4 (december 2013) 77 3. flow rate effect fig. (6) and (7) show the effect of flow rate of fs and ds on the flux of water respectively. fig. (6) explains that the flux of water increases by increasing the flow rate of fs while from fig. (7) the flux decreases by increasing the flow rate of ds for all four salts. increasing the flow rate of fs prevents the concentration buildup in the solution at the vicinity of the membrane surface, thus reducing the accumulated solute on the surface of the membrane and lead to increase the water flux. this behavior contradicts the case of increasing the ds flow rate. fig. (6) and (7) illustrate that the flow rate has slight effect on the flux compare with the effect of concentration of the ds. fig. 6, effect of flow rate of fs on the flux of water at concentration of ds = 10% by wt, flow rate of ds = 1 lit/min and temperatures of fs and ds = 20 o c fig. 7, effect of flow rate of ds on the flux of water at concentration of ds = 10% by wt , flow rate of fs = 1 lit/min and temperature of fs and ds = 20 o c 4. membrane flux resistance constant fig. (8) shows the osmotic pressure against concentration of sucrose [20]. after calibration of refractometer by depending on the literature given by randle [16] the sucrose content in the orange juice was measured where the refractive index was equaled to 1.3539 that gives the sucrose content in the juice = 13.9% by wt [16], then from fig. (8) the osmotic pressure of orange juice = 1180 kpa. fig. (9) shows the osmotic pressure against concentration of nacl solution [20]. at concentration of nacl = 10% by wt, from fig. (9) the osmotic pressure is evaluated to be 8700 kpa. from fig. (3) or (4), at 10% nacl by wt, temp = 20 o c for fs and ds , and flow rate = 1 lit/min for fs and ds, the flux of water = 3.605 lit/m 2 h. the membrane flux resistance constant ac is calculated at 20 o c from eq. (2): fw = ac ∆π 3.605 = ac (8700 – 1180) → ac = 4.8×10 -4 lit/m 2 h.kpa fig. 8, osmotic pressure of the sucrose against concentration flow rate of fs, lit/min f lu x , lit /m 2 h 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 nacl cacl 2 kcl mgso 4 flow rate of ds lit/min f lu x l it /m 2 h 0 1 2 3 4 5 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 nacl cacl 2 kcl mgso 4 %sucrose by wt o s m o ti c p re s s u re , k p a 200 600 1000 1400 1800 2200 2 6 10 14 18 22 26 concentration of orange juice using forward osmosis membrane process 78 ijcpe vol.14 no.4 (december 2013) -available online at: www.iasj.net fig. 9, osmotic pressure of the sodium chloride against concentration conclusion the obtained results in this research demonstrate the applying of forward osmosis (fo) process for the concentration of orange juice. the draw solution concentration is a serious parameter that influences water flux in the fo process where it has the biggest effect on the water flux compared with the others variables. temperature and flow rate were found to have a minor effect on the permeate water flux, where as increased the temperature leads to little increase in water flux for salts (nacl, cacl2, and kcl) and little decrease in water flux for mgso4 salt. also increasing of flow rate of fs or ds leads to little change in the flux, so it can be execute the fo membrane process at ambient temperature and with small scale pump. nacl salt gave higher osmotic pressure up to concentration of 15.2% by wt than the other salts (kcl, cacl2, mgso4) that used in the draw solution, but cacl2 gave higher osmotic pressure than nacl when the concentration exceed 15.2%. this technology can be applied for other fruit juices. nomenclature fs feed solution ds draw solution fo forward osmosis ro reverse osmosis ds draw solution oa osmotic agent edr electrodialysis reversal ac membrane flux resistance constant (lit/m 2 . h.kpa) c molar concentration (kmol/m 3 ) fw total water flux across the membrane (lit/m 2 .h) i dissociation factor (van't hoff factor) r gas constant (8.314 kj/kmol.k) t absolute temperature (k) ∆p hydrostatic pressure (kpa) π osmotic pressure (kpa) references 1pelin onsekizoglu, 2011, “membrane distillation: principle, advances, limitation and future prospects in food industry”, trakya university department of food engineering, edirne turkey, www.intechopen.com , p.1. 2george moise, vasile jascanu, 2008, “forward osmosis: theoretical background”, university of craiova, p.2. 3andy senecal, owen rehrauer, jack herron, danielle anderson, nicole favreau , and keith lampi, 2003, “self hydrating ration”, paper, held in boston, united states, 10-11 december and published in rto-mp-hfm-086, p.3. 4lawrence k. wang, jiaping paul chen, yung-tse hung, nazih k. shammas, 2011, “handbook of environmental engineering, membrane and desalination technology volume 13” © springer science and business media, llc, p.7. 5anthony jacob, 2006, “a critical review of the history, development and future prospects for forward osmosis”, elsevier 28th november, p. 1-3. concentration of nacl% by wt o s m o ti c p re s s u re , k p a 0 4000 8000 12000 16000 20000 0 4 8 12 16 20 http://www.intechopen.com/ khalid w. hameed -available online at: www.iasj.net ijcpe vol.14 no.4 (december 2013) 79 6michael t. flynn, monica soler, sara shull, james broyan, joe chambliss, a. scott howe, sherwin gormly, mona hammoudeh, hali shaw, and kevin howard, 2012, “forward osmosis cargo transfer bag” , 42nd international conference on environmental systems 15 19 july, san diego, california. p.3. 7steven j. duranceau, 2012, “emergence of forward osmosis and pressure-retarded osmotic processes for drinking water treatment” , florida water resources journal, july, p.1 8olawoyin richard, york jason, madu christian, li hang, ahn chong hyun, enab khalid, 2011, “optimization of well stimulation fluids in the marcellus shale gas development using integrated technologies” final report, p.5-8 9youn-kook kim and soo-young lee, 2008, “forward osmosis water treatment” techupdate, december, p.1. 10george moise, vasile jascanu, 2008, “forward osmosis: recent developments”, university of craiova, p.1 11ngai yin yip, alberto tiraferri, william a. phillip, jessica d. schiffman, and menachem elimelech, 2010, “high performance thin-film composite forward osmosis membrane”, environmental and science technology, vol. 44, no. 10, 38123818. 12stephen cross, 1989, “membrane concentration of orange juice”, proc. fla. hort. soc. 102: 146-152. 13corbitt, r., 1990, “standard handbook of environmental engineering”, mcgraw-hill, inc. ny, pp.5.147-5.148. 14sherwin gormly, michael flynn, and alex polonsky, 2010, “membrane based habitat wall architectures for life support and evolving structures” copyright © by the american institute of aeronautics and astronautics, p.4. 15jeffrey r. mccutcheon, robert l. mcginnisb, menachem elimelech, 2005, “a novel ammonia-carbon dioxide forward (direct) osmosis desalination process”, elsevier desalination 174, 1–11. 16randle a. macon, 2011, technical procedure manual, 2000, “brix measurement”, august, p.4-7. 17sigma-aldrich 2000. 18robert h. perry, don w. green, 1999, perry’s chemical engineering handbook, mcgraw hill, vol.2, p.276. 19hoffman a.m., 2008, ms.c. thesis “desing guidelines for a reverse osmosis desalination plant”, p. 41. 20thomas t. cochrane and thomas a. cochrane, 2005, “osmotic potential properties of solutes common in the soil-plant solution continuum” copyright © by lippincott williams, inc. printed in usa june, vol.170, no.6, p. 3-5. iraqi journal of chemical and petroleum engineering vol.14 no.1 (march 2013) 2537 issn: 1997-4884 simulation of cathodic protection system using matlab naseer a. al habobi and shahad f. abed al-nahrain university, college of engineering, chemical engineering department , baghdad, iraq abstract iraq has a huge network of pipelines, transport crude oil and final hydrocarbon products as well as portable water. these networks are exposed to extensive damage due to the underground corrosion processes unless suitable protection techniques are used. in this paper we collect the information of cathodic protection for pipeline in practical fields (oil group in al doura), to obtain data base to understand and optimize the design which is made by simulation for the environmental factors and cathodic protection variables also soil resistivity using wenner four terminal methods for survey sites; and soil ph investigations were recorded for these selected fields were within 7-8, and recording the anodes voltage and its related currents for the protection of underground pipelines. modeling enables the designer to build cathodic protection for buried structure and predicting the places of anodes sites and its operating voltages and currents under various operational conditions, and comparing it with those in practices. in this work we compared between the field and simulation results which include, anode numbers, rectifier voltage, rectifier current and anode resistance. the most economical design for the first pipeline was at station no. 2 which need 2.5 a for protection of the pipeline for that specific length and for second pipeline station no. 4 which need 12 a for protection of the pipeline for that specific length. keywords cathodic protection, pipelines, corrosion, impressed current cathodic protection, cathodic protection system design introduction cathodic protection (cp) is a method to reduce corrosion by minimizing the difference in potential between anode and cathode [1]. it is unique amongst all the methods of corrosion control in that if required it is able to stop corrosion completely, but it remains within the choice of the operator to accept a lesser, but quantifiable, level of protection [2]. this work presents a series of studies that examine the design and optimization of cathodic protection systems applied for the protection of buried pipelines. in this work, a general method for predicting the performance of cathodic protection systems and determining the best impressed cathodic protection system design has been presented. in this system, power is drawn from the national grid and converted into a dc iraqi journal of chemical and petroleum engineering university of baghdad college of engineering simulation of cathodic protection system using matlab 26 ijcpe vol.14 no.1 (march 2013) -available online at: www.iasj.net current by means of a transformerrectifier. from the basic electrochemical theory for absolute protection (zero corrosion rates) is achieved if the structure is polarized to the reversible electrode potential of the anodic reaction. field experience has shown that in aerated soils mild steel was fully protected at a potential of -850 mv vs. cu/cuso4 (800 mv vs. ag/agcl/seawater, +250 mv vs. zn/seawater and -780 mv vs. sce). it is important to note that the values quoted for the protection potential refer to the potential difference between the structure and the reference electrode without extraneous effects such as ir drop or field interference. potentials can vary seasonally as a result of variation in the soil moisture content. some pipeline companies perform annual surveys at the same time each year, so that trends in the behavior of a pipeline can be properly interpreted [3]. system description 1. pipelines the study of two pipelines made of carbon steel (carbon 0.1649 wt%, manganese 0.5027 wt% , phosphor 0.002 wt%, sulfur 0.0068 wt%, fe rest)and covered with coal tar coating; the first pipe 52km 0.254in diameter while the second 28km 0.406in diameter. the depth of each pipe is 1.20m. 2. ground bed ground beds are shallow type installed approximately from (100 150) m away from and horizontal to the pipe line in order to obtain suitable spread of current to the line according to the environment conditions. anode type were used are high silicon cast iron. ground beds were designed for locations remote from the cathode, allowing low current density transmission across long distances with moderate soil to pipe voltage at the line .in the data based from practices found that the optimum distance of the anode from the pipe is between 100 to 250 m. the depth of ground bed was between (2.5-3) m, their resistance varying from (1.6-0.464) ohm for the first pipe, while the second pipe from (0.9290.48) ohm. fifty anodes were used for the 52 km pipeline and twenty five anodes for the 28 km pipeline. in some installations where interference problems are severed, anode beds are sometimes installed deep below the surface. this causes the current flow to become more vertical and reduces interference between horizontally displaced structures. deep anodes are also used where the resistivity of the soil near the surface is high. identified the following desirable properties of an “ideal” impressed current anode material are [4]:  low consumption rate, irrespective of environment and reaction products  low polarization levels, irrespective of the different anode reactions high electrical conductivity and low resistance at the anodeelectrolyte interface. the lowest grounding resistance practically possible should be designed for in order to keep down the electric power and therefore the operating costs [5].  high reliability  high mechanical integrity to minimize mechanical damage during installation, maintenance, and service use  high resistance to abrasion and erosion  ease of fabrication into different forms  low cost, relative to the overall corrosion protection scheme 3. soil a characteristic feature of these desert soils is their lack of naseer a. al habobi and shahad f. abed -available online at: www.iasj.net ijcpe vol.14 no.1 (march 2013) 27 homogeneity. a multiplicity of low resistivity salty patches lie scattered throughout a matrix of high resistivity ground. the typical desert soil receives insufficient annual rainfall to carry soluble salts deep into the earth. a great number of salty patches are typical features of desert country, wherever the soil is of clayey nature with some powers of water retention; where the surface consists, however, of loose sandy particles with small waterholding power. the winter rainfalls do not penetrate deeply into the ground in these desert soils afforded by search for water-bearing formations [6]. the major soil or environmental factors that shall be considered for cathodic protection design are: soil resistivity, soil resistivity, the resistivity essentially represents the electrical resistance of a standardized cube of material [4]. ph of soil simulation to design an effective cathodic protection system we should be able to set up test programs, analyzes information acquired from different sources, construct profiles of corrosion problems, suggest operating or maintenance schemes, create test programs for selecting new materials or altering operating conditions, and devise remedial action plans for corrosion problems. for the cathodic protection of the pipeline, the number of the anodes is a very important design factor and playing a very important role, so this factor was optimized to observe the effect on the electric power necessary to keep the metal surface protected. designing and optimization by utilizing computer programs have been applied primarily to cathodic protection systems in soil. fig. (1) shows the simulation using matlab software version 7, 2010. 1. variables used for the simulation physical properties of the structure to be protected, anode used, soil resistivity, coating type, etc. where used in simulation. specification used in simulation: [7] 1. average soil resistivity in ohm.cm. 2. effective coating resistance at 15 years is estimated at 2500 ohms per square foot. 3. pipe outside diameter. 4. pipe length for the specified station. 5. design life. 6. design for 2 milliamperes per square foot of bare pipe. 7. design for 80 to 90 percent coating efficiency based on experience. 8. the pipeline must be isolated from the pump house with an insulating joint on the main line inside the pump house. 9. high silicon cast iron anodes must be used with carbonaceous backfill. specification about these anodes tabulated in tables 1 through 3. 10. anode bed must not exceed 2 ohms. 11. electric power is available at 240 volts ac single phase 50 hz or three phases from a nearby overhead distribution system. 12. current requirement test indicates that 2.36 amperes are needed for adequate cathodic protection. table 1, shape functions (k) for impressed current cathodic protection anodes where l is the effective anode length, d is anode/backfill diameter. [1] l/d k l/d k 5 0.014 28 0.0207 6 0.015 20 0.0213 7 0.0158 25 0.0224 8 0.0165 30 0.0234 9 0.0171 35 0.0242 10 0.0177 40 0.0249 12 0.0186 45 0.0255 14 0.0194 50 0.0261 16 0.0201 55 0.0266 simulation of cathodic protection system using matlab 28 ijcpe vol.14 no.1 (march 2013) -available online at: www.iasj.net table 2, weights and dimensions of high silicon chromium-bearing cast iron anodes [1] anode weight (lb.) anode dimensions (in) anode surface size (in) package area (sq. ft.) 12 1*60 1.4 10*84 44 2*60 2.6 10*84 60 2*60 2.8 10*84 110 3*60 4.0 10*84 table 3, anode paralleling factors (p) for various numbers of anodes (n) installed in parallel. [1] n p n p 2 0.00261 14 0.00168 3 0.00289 16 0.00155 4 0.00283 18 0.00145 5 0.00268 20 0.00135 6 0.00252 22 0.00128 7 0.00237 24 0.00121 8 0.0024 26 0.00114 9 0.00212 28 0.00109 10 0.00201 30 0.00104 12 0.00182 simulation inputs and outputs tabulated in tables 4 through 13 results a comparison between simulation results and the field (data based) tabulated below. for the first pipeline 4 stations (rectifiers) are used while the second pipeline 3 stations (rectifiers) are used. comparison between the simulation and data based (field) has been achieved, tables and figures below shows these results for these stations. pipe area=pi×d×l current requirement= a×i× (1-ce) total resistance (rt) =rc+rw+ra rectifier voltage= (i) × (rt) × (150%) deep anode groundbed rc (structure to electrolyte resistance)= rw(the groundbed header cable)= (ohms/ft)(l) ra(anode ground bed resistance)= where l length of protected structure at specified zone in m d pipe diameter in m ce coating efficiency i required current density ma/m 2 a total structure surface area m 2 a1 corrosion current densitym 2 /anode i1 recommended maximum current density output in ma n number of anodes l life in year w weight of anode in kg la length of anode backfill column in m k anode shape factor s center to center spacing between anode backfill column in m ra anode resistance in ohm rw the ground bed header cable resistance in ohm d anode /backfill diameter in m leff effective anode length in m naseer a. al habobi and shahad f. abed -available online at: www.iasj.net ijcpe vol.14 no.1 (march 2013) 29 rc resistance of cable header in ohm ldeep anode length in deep anodes ground bed in m ddeep anode diameter in deep anode ground bed in m v voltage r coating resistance in ohm fig. 1, simulation using mat lab software fig.s (2) and (3) show the pipelines description. simulation inputs and outputs tabulated in tables 8 through 15. curent requirement no. of anodes to meet the anode supplier current density no. of anodes tomeet the design life requirements maximam no. of anodes required to meet the groundbed requirements ra anode resistance rc structure to electrolyte resistance total resistance rt rw(the groundbed resistance to header cable) pipelength in ft pipe (od) in (in) design current density (ma/ft2) coating effieciency at (ft2/anode) it (ma/ft2) effective anode length in (ft) weight of one anode (lb) soil resistivity in (ohm.cm) anode shape factor (k) anode resistance in (ohm) p paralleling factor s (ft) coating resistance (ohm) resistance of cable in (ohm/100ft) header cable in ft constant constant constant 2100 0.0159 pi pi ohm4 ohm3 ohm2 ohm 7 1000 1.20 100 1 constant1 1000 constant anode2 anode1 anode 25 volt subtract4 subtract3 subtract2 subtract1 subtract 10 2 49200 10 0.00283 number of anodes needed 0.0165 1000 500 divide9 divide8 divide7 divide6 divide5 divide4 divide3 divide2 divide11 divide10 divide1 divide 1 constant 2500 0.8 12 convert in to ft 2.8 2 current ma simulation of cathodic protection system using matlab 30 ijcpe vol.14 no.1 (march 2013) -available online at: www.iasj.net fig. 2, first pipeline description fig. 3, second pipeline description + _ + + rectifier junction box anode zone 1 zone 2 zone 3 zone 4 _ + _ _ 100m from pipeline 20 anodes were used 100m from pipeline 10 anodes were used 150m from pipeline 10 anodes were used 120m from pipeline 10 anodes were used + _ + + rectifier junction box anode zone 1 zone 2 zone 3 zone 4 _ 5 anodes chain 50 m depth 50 m from pipeline 5 anodes chain 50 m depth 50 m from pipeline 10 anodes 100 m from pipeline 10 anodes 150 m from pipeline _ _ + naseer a. al habobi and shahad f. abed -available online at: www.iasj.net ijcpe vol.14 no.1 (march 2013) 31 table 4, the first pipe stations current requirement, voltage; number of anodes station no. soil resistivity (ohm.cm) real (field) simulation results ra (ohm) station 4 1500 12.5a 1.59a 1.6 7.5v 4.3v 10anodes 3anodes station3 1200 4v 12.9v 0.622 5a 11.9a 10anodes 10anodes station2 1000 2.5a 15.9a 0.464 7v 10.6v 10anodes 13anodes station 1 1500 59a 11.9a 1.13 48v 17.6v 10anodes 5anodes table 5, the second pipe stations current requirement, voltage; number of anodes used and need station no. soil resistivity (ω.cm) real (field) simulation results ra(ω) station 4 3000 5v 13v 0.68 (deep anode) 12a 8.9 a 5anodes 4 anodes station3 1000 14v 17.2v 0.754 24a 13.4a 10anodes 5anodes station2 1500 13a 17a 0.929 25v 22.2v 10anodes 11anodes station 1 1200 19a 16a 0.48 (deep anode) 14v 14v 5anodes 6anodes as given in tables (6) and (7) the anodes used in each station and the length of pipe that protected by these anodes. table 6, first pipeline stations station number anodes number distance between anode and pipeline m zone length km station 1 20 100 15 station 2 10 100 20 station 3 10 150 15 station 4 10 120 2 table 7, second pipeline stations station number anodes number distance between anode and pipeline m zone length km station 1 5 chain 55m depth 50 deep 7 station 2 10 150 7 station 3 10 100 7 station 4 5 chain 55 m depth 50 deep 7 table 8, simulation results for zone 1 of the second pipeline simulation output simulation input 8939.48 pipe area m 2 2500 coating resistance ohm 16091.1 current requirement ma 7000 pipe length m 5.74682 no. of anodes to meet the anode supplier current density 0.406 pipe od m 1.519 no. of anodes need to meet the design life requirement 17.99 current density ma/m 2 0.9937 maximum no. of anodes required to meet the ground bed requirements 0.9 coating effecincy 0.48 resistance for deep anode 0.260 at m 2 /anode 0.0795 rw 10758 it ma/m 2 0.02599 rc 11.36 w kg 0.5832 rt 25 life in yaer 14.077 rectifier voltage v 1200 soil resistivity ohm.cm 2.36 amp. needs for adequate cp 2.13 l effective anode length m simulation of cathodic protection system using matlab 32 ijcpe vol.14 no.1 (march 2013) -available online at: www.iasj.net table 9, simulation results for zone 2 of the second pipeline simulation output simulation input 8939.5 pipe area m 2 2500 coating resistance ohm 17879 current requirement ma 7000 pipe length ft 6.3854 no. of anodes to meet the anode supplier current density 0.406 pipe od in 10.727 no. of anodes need to meet the design life requirement 19.99 current density ma/sqft 2.244 maximum no. of anodes required to meet the ground bed requirements 0.9 coating effecincy 0.7459 ra 0.2602 at sqft/anode 0.0795 rw 10758.4 it ma/sqft 0.026 rc 11.363 w lb 0.8514 rt 15 life in yaer 18.267 rectifier voltage 1200 soil resistivity ohm.cm 2.36 amp. needs for adequate cp 2.13 l effective anode length m table 10, simulation results for zone 3 of the second pipeline simulation output simulation input 8939.48 pipe area m 2 2500 coating resistance ohm 13409 current requirement ma 7000 pipe length m 4.789 no. of anodes to meet the anode supplier current density 0.406 pipe od m 1.2658 no. of anodes need to meet the design life requirement 14.999 current density ma/m 2 1.3728 maximum no. of anodes required to meet the ground bed requirements 0.9 coating effecincy 0.7544 ra 0.2602 at m 2 /anode 0.0795 rw 10758 it ma/m 2 0.026 rc 11.36 w kg 0.8599 rt 25 life in yaer 17.296 rectifier voltage v 1000 soil resistivity ohm.cm 2.36 amp. needs for adequate cp 2.13 l effective anode length m table 11, simulation results for zone 4 of the second pipeline simulation output simulation input 8939.48 pipe area m 2 2500 coating resistance ohm 8939.49 current requirement ma 7000 pipe length m 3.1926 no. of anodes to meet the anode supplier current density 0.406 pipe od m 0.84389 no. of anodes need to meet the design life requirement 9.999 current density ma/m 2 1.3728 maximum no. of anodes required to meet the ground bed requirements 0.9 coating effecincy 0.68 ra 0.260 at m 2 /anode 0.0795 rw 10758.4 it ma/m 2 0.21186 rc 11.36 w kg 0.97387 rt 25 life in yaer 13.0588 rectifier voltage v 3000 soil resistivity ohm.cm 2.36 amp. needs for adequate cp 2.13 l effective anode length m naseer a. al habobi and shahad f. abed -available online at: www.iasj.net ijcpe vol.14 no.1 (march 2013) 33 table 12, simulation results for zone 1 for the first pipeline simulation output simulation input 11972.5 pipe area m 2 2500 coating resistance ohm 11973 current requirement ma 15000 pipe length m 4.2759 no. of anodes to meet the anode supplier current density 0.254 pipe od m 3.3523 no. of anodes need to meet the design life requirement 9.999 current density ma/ m 2 2.2442 maximum no. of anodes required to meet the ground bed requirements 0.9 coating effecincy 1.1316 ra 0.2602 at m 2 /anode 0.0795 rw 10758 it ma/ m 2 0.0194 rc 11.36 w kg 1.2306 rt 20 life in yaer 17.679 rectifier voltage v 1500 soil resistivity ohm.cm 2.36 amp. needs for adequate cp 2.13 l effective anode length m table 13, simulation results for zone 2 of the first pipeline simulation output simulation input 15963.34 pipe area m 2 2500 coating resistance ohm 7981.7 current requirement ma 20000 pipe length m 2.8506 no. of anodes to meet the anode supplier current density 0.254 pipe od m 6.3854 no. of anodes need to meet the design life requirement 4.999 current density ma/m 2 2.2442 maximum no. of anodes required to meet the ground bed requirements 0.9 coating effecincy 0.9296 ra 0.2602 at m 2 /anode 0.0795 rw 10758 it ma/ m 2 0.0146 rc 11.36 w kg 01.0237 rt 20 life in yaer 9.8046 rectifier voltage v 1500 soil resistivity ohm.cm 2.36 amp. needs for adequate cp 2.13 l effective anode length m table 14, simulation results for zone 3 of the first pipeline simulation output simulation input 11972.50 pipe area m 2 2500 coating resistance ohm 11973 current requirement ma 15000 pipe length m 4.2759 no. of anodes to meet the anode supplier current density 0.254 pipe od m 9.578 no. of anodes need to meet the design life requirement 9.999 current density ma/ m 2 1.7035 maximum no. of anodes required to meet the ground bed requirements 0.9 coating effecincy 0.6225 ra 0.2602 at m 2 /anode 0.0795 rw 10758 it ma/ m 2 0.0194 rc 11.36 w kg 0.7214 rt 20 life in yaer 12.955 rectifier voltage v 1200 soil resistivity ohm.cm 2.36 amp. needs for adequate cp 2.13 l effective anode length m simulation of cathodic protection system using matlab 34 ijcpe vol.14 no.1 (march 2013) -available online at: www.iasj.net table 15, simulation results for zone 4 of the first pipeline simulation output simulation input 1596.33 pipe area m 2 2500 coating resistance ohm 1596.3 current requirement ma 2000 pipe length m 0.5701 no. of anodes to meet the anode supplier current density 0.254 pipe od m 0.1507 no. of anodes need to meet the design life requirement 9.999 current density ma/ m 2 2.2442 maximum no. of anodes required to meet the ground bed requirements 0.9 coating effecincy 1.6031 ra 0.2602 at m 2 /anode 0.0795 rw 10758 it ma/ m 2 0.1456 rc 11.36 w kg 1.8281 rt 20 life in yaer 4.3775 rectifier voltage v 1500 soil resistivity ohm.cm 2.36 amp. needs for adequate cp 2.13 l effective anode length m fig. 4, the difference between field and simulation work for applied voltage for the 28 km pipeline fig. 5, the difference between field and simulation work for applied voltage for the 52 km pipeline fig. 6, the anode resistance variation between the simulation work and field for each station for the 28km pipeline fig. 7, the relation between the anode resistance and applied voltage for the 28km pipeline 10 12 14 16 18 20 22 24 26 0 10 20 30 a p p lie d v o lt a g e a t re ct if ie r. (v o lt ) pipe length in km simulation field 0 5 10 15 20 0 20 40 60 a p p lie d v o lt a g e ( vo lt ) pipe length in km simulat… field 0 0.5 1 1.5 2 0 10 20 30 a n o d e r e si st a n ce ( o h m ) pipe length in km field simulation 10 12 14 16 18 20 22 24 26 0 1 2 a p p lie d v o lt a g e a t re ct if ie r (v o lt ) anode resistance (ohm) field simulation naseer a. al habobi and shahad f. abed -available online at: www.iasj.net ijcpe vol.14 no.1 (march 2013) 35 fig. 8, the relation between the anode numbers versus anode resistance for the 52 km pipeline fig. (4) through fig. (8) show the comparison of between the simulation and field results. discussion  the design of cathodic protection voltage and current is mostly depend on the potential of the pipe, if it is protected this mean that the work is efficient.  in fully coated pipe near the pipe or remote it would not make any difference as the coating resistance makes up most of the resistance between the pipe and the soil [7].  both the operating cost (power consumption) and installation cost are influenced by the resistance of the anode bed. it is, rather, the one whose resistance is such as to fit into an overall system whose total annual cost is the least, this accomplish with low soil resistivity enhances cp by lowering the anode to earth resistance, thus allowing higher current output for a given voltage [8] high silicon cast iron hsci anodes rely on the formation of a protective oxide film (mainly hydrated sio2) for corrosion resistance. the chromium alloying additions are made for use in chloride containing environments to reduce the risk of pitting damage [9]. casing must be electrically isolated from the carrier pipe; wires on both the pipeline and the casing, the vent can be used instead, there should be difference of anywhere from about 0.25v to 1.0v or more between the pipe to soil potential of the casing has anodes connected to it, the difference may be smaller in that case current pick up or resistance tests between the casing and the pipeline may be required [8].  the soil ph measured in the field areas was within a range of 7-8 which is slightly alkaline and within those values, soil ph did not indicate soil acidity to be a corrosion factor. from the results of the laboratory and field measurements, it was apparent that any underground metallic piping or structures on the selected sites would be subjected to various resistivity's' environments. soil varies over short distance of depth, and from season to season. this is often a problem in desert conditions, where the surface can be of extremely high resistivity soil resistivity survey results must always be used with the wenner method measures average and apparent values. rectifier types used depends on the current demand. the current consumption is the lowest when it is uniformly distributed over the pipeline, however. such a distribution requires too much drainage sites; near the drainage sites the local current densities are several times higher than at the end of protected zone. it's also depends on the pipeline geometry, wall thickness, depth of lying. when this maximum current is drained from a point, the pipe to soil potential is a maximum current at the drain point, the resistance of the structure causes the current to decrease nonlinearly as a 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 0 5 10 15 a n o d e r e si st a n ce ( o h m ) no. of anodes simulation of cathodic protection system using matlab 36 ijcpe vol.14 no.1 (marcch 2013) -available online at: www.iasj.net function of distance from a drain point. a drain point refers to the point on the structure where its electrical connection to the anode is made [9]. the variations and the differences between the total current required for the protection which calculated by the derived equations and those measured during field designing procedure are referred to the high accuracy of the software calculations. the total current calculated from the software was higher than the current applied and measured in the field in some stations, i.e. the total current required for the second pipeline stations 2, 3 and stations 2, 3 for the first pipeline. there was an exception case, where the total current calculated by the model equation was more than the value measured in the field. this exception was recorded when the soil resistivity, the anode resistance, anode numbers values change these three factors change and here is some explanation: 1. as the number of anodes increase the total resistance of anodes decrease 2. the arrangement of anodes is parallel so the current of more than one anode is greater than for one anode for the same rectifier (applied) voltage. this is appear in figure 3. as the anode distance between anode and the pipeline increase the region of pipe to be protected will increase. 4. current density should be kept low to prevent undue drying out of the soil around the anode as a result of chlorine the localized current density increases and chlorine gas generation also increases in the absence of proper venting this too can lead to premature failure [10].  conductivity (resistivity) of the soil is playing two important roles in the design criteria of cathodic protection systems. the first role is occurring when placing the anode in a high conductivity environment; more uniform current and potential distribution will take place. in case of current distribution, the higher soil conductivity the higher current passing through the soil and as a consequence the lower in power consumption. moreover, for the potential distribution, the lower in soil conductivity, the higher in potential needed to drive the current, and as a consequence the higher in power consumption. second role is where the hydrogen evolution may occur in the surface of the cathode facing the anode due to the high value of the potential. conclusion  in conclusion, it is believed that in design of an efficient anode system, the proper configuration should be selected, with in the limitations of space and materials available. it is realized that there are no set rules for establishing cathodic protection because there are so many variables and each case must be individually considered. in this light, the foregoing discussion has been presented with hope that it may add to the sum total of previous statements of experiences and recommendations for establishing more efficient systems of cathodic protection.  this paper shows that the best anode positions was from 50-150 m away from pipeline to give a better protection for the pipeline, and the anode grounded resistance decrease as the no. of anodes increases.  additional anodes can be used to achieve a more homogeneous ionic current flow, where an optimum anode-to-cathode separation distance cannot be achieved. resistivity variations in the naseer a. al habobi and shahad f. abed -available online at: www.iasj.net ijcpe vol.14 no.1 (march 2013) 37 electrolyte between the anode and cathode also have a strong influence on the current distribution. areas of low resistivity will “attract” a higher current density, with current flowing preferentially along the path of least resistance. references 1. us army, "cathodic protection" technical manual, ufc 3-570-02a, 2005, pp. 1-1: f-4. 2. shrier l.l, r.a. jarman and g. t. burstein, "corrosion and corrosion control", volume 2, 3 rd edition, 1993. 3. a. w. peabody, "control of pipeline corrosion", 2 nd edition, 2001. 4. pierre r. roberge, and mcgraw, "handbook of corrosion engineering” 2000. 5. w.von baeckmann, w.schwenk, and w. prinz, "handbook of cathodic corrosion protection", 3 rd edition 1997. 6. w.c.r. whalley, “cathodic protection in desert soils”, corrosion, no.11, vol. 17, 1961, pp559t_565t. 7. ahmed z., "principle of corrosion engineering and corrosion control", 2006. 8. 8. nace international, "cathodic protection tester course manual". 2007. 9. roberge p. r., "handbook of corrosion engineering", mcgraw – hill, 1999. 10. matcor, “deep well anode system design” technical bulletin, dw-01, tah v1.0, 2008, pp.1_9. iraqi journal of chemical and petroleum engineering vol.13 no.2 (june 2012) 3745 issn: 1997-4884 thickening time and compressive strength correlations for bentoniticclass "g" cement slurries riyadh hazim fawzi baghdad university, college of engineering, department of petroleum engineering, baghdad, iraq abstract empirical equations for estimating thickening time and compressive strength of bentonitic class "g" cement slurries were derived as a function of water to cement ratio and apparent viscosity (for any ratios). how the presence of such an equations easily extract the thickening time and compressive strength values of the oil field saves time without reference to the untreated control laboratory tests such as pressurized consistometer for thickening time test and hydraulic cement mortars including water bath ( 24 hours ) for compressive strength test those may have more than one day. الخالصة لسمنت نوع "ج" المحضر بالبنتونايت والذ ي يمثل ةللتنبؤ بقيم زمن التثخن وقوه الصالب ةالمعادالت التجريبي )لمختلف النسب(. ان استعمال معادالت للتنبؤ بقيم زمن ةالظاهري ةالماء الى السمنت واللزوج ةلنسب ةكدال الحقل النفطي يوفر الوقت دون الرجوع الى الفحص المختبري واستعمال ة في التثخن وقوه الصالب ة( لقياس قوة صالبةساع 42) ةوالحمام المائي لمدة السمنت واعمدلقياس زمن التثخن ةالخاص ةاالجهز السمنت وكلها قد تحتاج الى اكثر من يوم. keywords correlations, thickening time, compressive strength, drilling, cementing materials. introduction physical and rheological properties of cement slurries with additives are important tools in cementing jobs. many investigation were made by researchers, manufactures and service companies to evaluate each addition in both the laboratory and the field. ibrahim [1] performed laboratory tests on class "g" cement slurries containing different bentonite to cement ratios (dry bentonite), his results were 28 different plots and two correlation equations for thickening time and free water content. data all cement slurries data from ibrahim [1] (experimental work) , the range of data and data used are shown in tables (1) and (2) respectively and the (m) values were calculated from this study. iraqi journal of chemical and petroleum engineering university of baghdad college of engineering thickening time and compressive strength correlations for bentoniticclass "g" cement slurries 38 ijcpe vol.13 no.2 (june 2012) -available online at: www.iasj.net correlations 1. thickening time correlations 1.1. thickening time correlation(this study) the following general relation of thickening time of cement slurries with its rheological properties was assumed. thickening time = f (ú, m ) …(1) thickening time  ( 1/ú,m ) …(2) table (2) shows 30 experimental points that were used to develop the following correlation equation ( this study ) , non linear model was used to develop the following relation: t.t = a1 +exp ( a2 + a3/ú + a4*m + a5/ú 2 + a6*m 2 + a7/ú 3 + a8*m 3 + a9/ú 4 + a10*m 4 + a11/ú 5 + a12*m 5 ) …(3) where a1 = 9150.24 a2 = 9.360349 a3 = 4.384563 a4 = -1.60827 a5 = 239.746 a6 = 3.909896 a7 = 6054.842 a8 = 4.61193 a9 = 68215.6 a10 = 2.641999 a11 = 285946.6 a12 = 0.588621 1.2. thickening time correlation (ibrahim[1]) ibrahim [1] wrote the following equation using apparent viscosity range of 35 to 95 c.p . but in this study and for comparative purposes , the following equation was used for all data. t.t = 134.1 0.427 * ú …(4) he assumed thickening time = f (ú ) …(5) thickening time  (ú ) …(6) 2. compressive strength correlation (this study) compressive strength = f (ú, m) …(7) compressive strength (ú,1/m) …(8) also table (2) shows the 32 experimentally points that were used to write the following correlation equation(this study),also non linear model was used to write the following relation. c.s. = a1 + a2/m + a3*ú + a4/m2 + a5*ú 2 + a6/m3 + a7*ú 3 + a8/ m4 + a9*ú 4 …(9) where a1 =16934.070004 a2 = 53758.83433 a3 = 7.52898677 a4 = 62273.823273 a5 = 0.1502096603 a6 =29671.46878 a7 = 0.0022956086 a8 = 5139.7132478 a9 = 0.0000077643 statistical analysis the statistical parameter used for comparison equations for those parameters are given below: 1. average percent relative error it is the measure of the relative deviation in percent from the experimental data and defined by:    n i ei n er 1 1 …(10) where ei is the relative deviation in percent of an estimated value from the experimental value ,,...2,1100 exp exp ni x xxest ei         ...(11) riyadh hazim fawzi -available online at: www.iasj.net ijcpe vol.13 no.2 (june 2012) 39 where x est and x exp represent the estimated and experimental values, respectively. 2. average absolute percent relative error it can be represented by the following formula    n i ei n ea 1 1 …(12) 3. minimum and maximum absolute percent relative error calculation of both minimum and maximum values are scanned to know the range of error for each correlation. ei n i e min 1min   …(13) ei n i e max 1max   …(14) 4. standard deviation (sx) standard deviation, sx , is the measures of the data dispersion around zero deviation.    n i ie n sx 1 2 2 1 1 …(15) 5. correlation coefficient (r) the correlation coefficient, r , represents the degree of success in reducing the standard deviation by regression analysis.                      n i i n i i xx xestx r 1 2 1 2 2 )exp( exp )( 1 …(16) where    n i i x n x 1 exp)( 1 …(17) results and analysis 1. results and discussion tables (3, 4 and 5) show a the comparison between errors experimentally thickening time of 30 estimated data points and the experimentally compressive strength of 32 data points from two correlations of the thickening time and one correlation of the compressive strength. the correlation for thickening time of this study eq.(3) achieved the lowest errors and standard deviation, with the highest correlation coefficient accuracy ( this study ) of 0.9957 comparison with the correlation coefficient accuracy ( ibrahim[1] ) of 0.4335. the correlation for compressive strength eq.(9) achieved the high correlation coefficient of 0.9904. 2. cross plots the cross plots of estimated vs. experimental values for thickening time correlations are shown in figs. (1) and (2) most of the plotted points of this study's fig. (1) correlation fall very close to the perfect correlation of 45 o line ( 0.79 rad ). the correlation of ibrahim[1] fig.(2 ) reveal more overestimation than this study. also the cross plot of estimated vs. experimental values compressive strength correlation are presented in fig.(3) of the plotted data points of this study's. thickening time and compressive strength correlations for bentoniticclass "g" cement slurries 40 ijcpe vol.13 no.2 (june 2012) -available online at: www.iasj.net riyadh hazim fawzi -available online at: www.iasj.net ijcpe vol.13 no.2 (june 2012) 41 3. error distribution the statistical histograms with normal distribution curve for the thickening time correlation of this study and ibrahim[1] are presented in fig.( 4) and ( 5) . the error ranges of (± 20 ) and (+60 to -80 ) are used for this study's and ibrahim[1]. correlations respectively. fig. (6) shows the distribution for this study's correlation for compressive strength is (+30) and ( -40). 4. conclusion 1. thickening time and compressive strength correlations for bentonitic – class "g" cement slurries have been estimated using equations (3) and (9) respectively. 2. equations (3) and (9) can be used for estimating all water/cement ratios and apparent viscosity without using any devices . 3. deviations from experimentally data, indicated as average percent relative error , average absolute percent relative error, minimum and maximum absolute percent relative error and standard deviation were lower for this study than for estimation based on the correlation of ibrahim[1]. 4. the correlation coefficients of the correlations of this study that are excellent and near one. nomenclature. apre = average percent relative error, (%) ,eq. (10) c.s. = compressive strength,(psi) eq.(9) c.s.est = estimated compressive strength, (psi) ea = average absolute percent relative error, (%), eq.(12) ei = percent relative error, (%), eq.(11) max e = maximum absolute percent relative error, (%), eq.(14) min e = minimum absolute percent relative error, (%), eq. (13) er = average percent relative error, (%) , eq.(10) f = function f.w = free water content, (%) m = water to cement ratio (by weight), dimensionless mo = bentonite to cement ratio (by weight), dimensionless ms = water to solid ratio (by weight), dimensionless n = number of variables r = correlation coefficient, eq.(16) = standard deviation, eq. (15) t.t. = thickening time,(minutes),eq.(3,4) t.t.est = estimated thickening time, (minutes) t.t.exp = experimental thickening time, (minutes) ú = apparent viscosity = ø600/2 ,c.p [pa.s] x = average value of x exp, eq.(17) x est = estimated value of x, x exp = experimental value of x ρ = slurry density, gm/cc subscriptes est estimated from correlation exp experimental max maximum min minimum si metric conversion factors atm  1.013 250* e + 05 = pa cp  1.0 * e 03 = pa·s o f ( o f + 459.67)/1.8 = k psi 6.894 757 e + 00 = kp references 1. ibrahim , m.i. , (1989). establishment of graphical relationships between ingredients of bentonitic –cement slurry and its main physical and sx thickening time and compressive strength correlations for bentoniticclass "g" cement slurries 42 ijcpe vol.13 no.2 (june 2012) -available online at: www.iasj.net rheological properties. m.sc thesis baghdad university , college of engineering , department of petroleum engineering, iraq. 2. london: w.h. aleen and co., ltd. (1973). hayslett , h.t.,statistics made simple 3. naji tawfik. and rashid al – salihi, (1989). engineering statistics. . baghdad university , college of engineering. iraq : higher education publication. table 2 , slurry and set class "g" cement properties at variable bentonite and water proportions (ibrahim[1]) table 1, range of data bentonite/cement ratio, dimensionless 2/98 to 12/88 water/solid ratio, dimensionless 0.4 to 1.05 water/cement ratio, dimensionless 0.408 to 1.136 apparent viscosity, c.p 9.5 to 138 slurry density, gm/cc 1.49 to 1.94 thickening time, minutes 51 to 430 compressive strength, psi 420 to 2530 free water content, % nil to 19 mo=2/98 sample no. ms m ú (at 80 o f) c.p ρ gm/cc thickening time (at 125 o f, 5200psi) minutes compressive strength (at 140 o f and 24-hures) psi f.w % a1 ! a2 * " a3*" a4 *" a5 *" a6 *" a7 " 0.40 0.50 0.60 0.70 0.80 0.90 1.00 0.408 0.510 0.612 0.714 0.816 0.918 1.02 120.5 80.0 56.0 36.0 21.5 12.0 9.50 1.94 1.83 1.74 1.67 1.61 1.56 1.51 --- 94 109 123 184 430 --- --- 2530 2187 1600 1480 1093 812 nil 0.6 1.8 2.3 5.4 12.0 19.0 mo=4/96 sample no. ms m ú (at 80 o f) c.p ρ gm/cc thickening time (at 125 o f , 5200 psi) minutes compressive strength (at 140 o f and 24-hures) psi f.w % b1*" b2*" b3*" b4*" b5*" b6*" 0.50 0.60 0.70 0.80 0.90 1.00 0.521 0.625 0.729 0.833 0.938 1.042 99.0 72.0 48.0 32.0 22.0 19.0 1.83 1.73 1.66 1.60 1.55 1.51 63 96 111 130 165 220 2380 1683 1553 1120 800 678 nil 1.3 1.8 3.7 5.7 7.2 riyadh hazim fawzi -available online at: www.iasj.net ijcpe vol.13 no.2 (june 2012) 43 (*) used in the thickening time correlation equation. (") used in the compressive strength correlation equation. (!) not used. the (m) values were calculated from this study. table 2 , slurry and set class "g" cement properties at variable bentonite and water proportions (ibrahim[1]) (continued) mo=6/94 sample no. ms m ú (at 80 o f) c.p ρ gm/cc thickening time (at 125 o f , 5200 psi) minutes compressive strength (at 140 o f and 24-hures) psi f.w % c1" c2*" c3*" c4*" c5*" c6*" c7 ! 0.50 0.60 0.70 0.80 0.90 1.00 1.05 0.532 0.638 0.745 0.851 0.957 1.064 1.117 138.0 97.0 71.0 48.0 28.5 19.5 17.0 1.83 1.73 1.66 1.60 1.55 1.51 1.49 --- 79 97 111 135 211 --- 2330 1650 1180 1000 650 533 --- nil nil 0.95 1.70 3.80 5.40 7.40 mo=8/92 sample no. ms m ú cp at 80 o f ρ gm/cc thickening time (at 125 o f,5200 psi) minutes compressive strength psi (at 140 o f and 24-hures) f.w % d1 ! d2" d3*" d4*" d5*" d6*" d7*" 0.50 0.60 0.65 0.70 0.80 0.90 1.00 0.543 0.652 0.707 0.761 0.870 0.978 1.087 --- 128.0 109.0 91.0 62.0 39.0 25.0 1.83 1.73 1.69 1.66 1.60 1.55 1.51 --- --- 51 95 104 116 151 2212 1620 1381 1150 543 533 450 nil nil nil 0.20 0.60 1.45 4.00 mo=10/90 sample no. ms m ú (at 80 o f) c.p ρ gm/cc thickening time (at 125 o f, 5200 psi) minutes compressive strength psi (at 140 o f and 24-hures) f.w % e1 ! e2 ! e3*" e4*" e5*" e6*" e7*" 0.50 0.60 0.70 0.75 0.80 0.90 1.00 0.556 0.667 0.778 0.833 0.889 1.00 1.111 --- --- 111.5 94.5 75.5 46.0 26.5 1.83 1.73 1.66 1.63 1.60 1.55 1.51 --- --- 53 94 98 113 140 2190 1590 1140 622 530 515 428 nil nil nil nil 0.3 0.8 3.5 mo=12/88 sample no. ms m ú (at 80 o f) c.p ρ gm/cc thickening time (at 125 o f , 5200 psi) minutes compressive strength psi (at 140 o f and 24-hures) f.w % f1 ! f2 ! f3*" f4* f5*" f6*" 0.50 0.70 0.80 0.85 0.90 1.00 0.568 0.795 0.909 0.966 1.023 1.136 --- --- 101.5 78.0 60.0 33.0 1.83 1.66 1.60 1.57 1.55 1.51 --- --- 55 94 101 127 2175 1087 516 --- 431 420 nil nil nil 0.3 0.6 2.3 thickening time and compressive strength correlations for bentoniticclass "g" cement slurries 44 ijcpe vol.13 no.2 (june 2012) -available online at: www.iasj.net table 3, comparision of thickening time estimated by correlations from this study and ibrahim[1] t.t.est tt.exp ibrahim minutes t.t.est tt.exp (this study) minutes deviation in percent of estimated thickening time (apre) estimated thickening time (t.t.est) minutes experimental thickening time (t.t.exp) minutes no. ibrahim this study ibrahim this study 2.340 -3.842 2.490 -4.088 96.340 90.158 94 1 -1.332 -0.116 -1.222 -0.106 107.668 108.884 109 2 -5.892 -1.921 -4.790 -1.562 117.108 121.079 123 3 -60.048 0.690 -32.635 0.375 123.952 184.690 184 4 -301.56 0.059 -70.131 0.014 128.436 430.059 430 5 24.37 5.360 38.686 8.508 87.372 68.360 63 6 4.116 0.317 4.288 0.330 100.116 96.317 96 7 0.444 6.914 0.400 6.229 111.444 117.914 111 8 -11.004 -5.178 -8.465 -3.983 118.996 124.822 130 9 -41.284 9.184 -25.021 5.566 123.716 174.184 165 10 -94.868 -3.013 -43.122 -1.370 125.132 216.987 220 11 9.316 -8.436 11.792 -10.679 88.316 70.564 79 12 3.588 5.247 3.700 5.409 100.588 102.247 97 13 0.444 5.522 0.400 4.975 111.444 116.522 111 14 -14.352 -6.189 -10.631 -4.584 120.648 128.811 135 15 -86.104 -1.208 -40.808 -0.572 124.896 209.792 211 16 31.652 10.343 62.063 20.279 82.652 61.343 51 17 -3.852 -13.598 -4.055 -14.314 91.148 81.402 95 18 0.836 3.817 0.804 3.670 104.836 107.817 104 19 -0.308 -1.383 -0.266 -1.192 115.692 114.617 116 20 -28.700 -1.397 -19.007 -0.925 122.300 149.603 151 21 28.472 6.849 53.721 12.923 81.472 59.849 53 22 -4.504 -17.541 -4.791 -18.660 89.496 76.459 94 23 0.464 -3.455 0.473 -3.525 98.464 94.545 98 24 -0.612 -0.116 -0.542 -0.103 112.388 112.884 113 25 -18.408 2.588 -13.149 1.848 121.592 142.588 140 26 31.192 11.048 56.713 20.087 86.192 66.048 55 27 3.284 -4.525 3.494 -4.813 97.284 89.475 94 28 4.780 5.202 4.733 5.150 105.780 106.202 101 29 -8.476 -0.418 -6.674 -0.329 118.524 126.582 127 30 riyadh hazim fawzi -available online at: www.iasj.net ijcpe vol.13 no.2 (june 2012) 45 table 4, compressive strength estimated by correlation from this study c.s.est c.s.exp (this study) psi deviation in percent of estimated compressive strength (apre) estimated compressive strength (c.s.est) psi experimental compressive strength c.s.exp) psi no. 2.983 0.118 2532.983 2530 1 -201.077 -9.194 1985.923 2187 2 84.385 5.274 1684.385 1600 3 -129.561 -8.754 1350.439 1480 4 -48.924 -4.476 1044.076 1093 5 -21.979 -2.707 790.021 812 6 0.695 0.029 2380.695 2380 7 134.612 7.998 1817.612 1683 8 -66.849 -4.305 1486.151 1553 9 36.986 3.302 1156.986 1120 10 71.182 8.898 871.182 800 11 -30.019 -4.428 647.981 678 12 2.903 0.125 2332.903 2330 13 61.682 3.738 1711.682 1650 14 53.688 4.550 1233.688 1180 15 -87.448 -8.745 912.552 1000 16 91.044 14.010 741.044 650 17 72.800 13.660 605.800 533 18 46.823 2.890 1666.823 1620 19 -18.372 -1.330 1362.628 1381 20 -59.576 -5.181 1090.424 1150 21 174.781 32.190 717.781 543 22 34.872 6.543 567.872 533 23 62.419 13.870 512.419 450 24 -125.727 -11.030 1014.273 1140 25 127.834 20.550 749.834 622 26 37.029 6.987 567.029 530 27 -73.193 -14.210 441.807 515 28 40.579 9.481 468.579 428 29 -67.969 -13.170 448.031 516 30 -161.247 37.412 269.753 431 31 -45.354 -10.800 374.646 420 32 table 5, statistical accuracy ot thickening time and compressive strength correlations compressive strength thickening time this study 0.5771 9.0610 0.0292 37.4122 12.2285 0.9904 ibrahim[1] this study 0.8186 -1.3851 5.5389 17.6353 0.0136 0.2655 20.2794 70.1312 8.1341 27.3976 0.9957 0.4335 average relative error , % average absolute relative error , % minimum absolute relative error , % maximum absolute relative error, % standard deviation , % correlation coefficient available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.22 no.2 (june 2021) 27 – 35 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: khalid khazzal hummadi , email: dr.khalid.hummadi@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. optimal operating conditions for adsorption of heavy metals from an aqueous solution by an agriculture waste khalid khazzal hummadi university of baghdad, college of engineering, baghdad, iraq abstract the aim of this work is to detect the best operating conditions that effect on the removal of cu 2+ , zn 2+ , and ni 2+ ions from aqueous solution using date pits in the batch adsorption experiments. the results have shown that the al-zahdi iraqi date pits demonstrated more efficient at certain values of operating conditions of adsorbent doses of 0.12 g/ml of aqueous solution, adsorption time 72 h, ph solution 5.5 ±0.2, shaking speed 300 rpm, and smallest adsorbent particle size needed for removal of metals. at the same time the particle size of date pits has a little effect on the adsorption at low initial concentration of heavy metals. the adsorption of metals increases with increasing the initial of metal concentration while above the 85 ppm, the removal efficiency was decreased. the phenomenon of adsorption of heavy metals on to al-zahdi iraqi date pits is exothermic process. the maximum adsorption capacity according to the langmuir equation was 0.21, 0.149, and 0.132 mmol/g for cu 2+ , zn 2+ , and ni 2+ respectively. the adsorption equilibrium was well described by the freundlich model. the results of freundlich constants indicated that the adsorption capacity and adsorption intensity of copper is larger than the zinc and nickel. the intraparticle diffusion was involved is this process but it is not the controlling step. the results of this study may inspire to find the optimal operating conditions for adsorption and develop that with large-scale production to clean the polluted water with heavy metals. keywords: adsorption, heavy metals. al-zahdi iraqi date pits, wastewater, freundlich. received on 24/01/2021, accepted on 14/04/2021, published on 30/06/2021 https://doi.org/10.31699/ijcpe.2021.2.4 1introduction the contamination of water with heavy metals is the biggest problem in the environmental pollution because of their tending to accumulate in the living organisms and cannot be degraded, therefore cause various diseases [1, 2, 3]. the world health organization (who) stated that the permissible of cu 2+, zn 2+ , and ni 2+ for drinking water are 1, 3, and 5 ppm respectively [4]. there are many physical and chemical processes are available for the removal of heavy metals from wastewater, such as electrochemical precipitation, ultrafiltration, solvent extraction, sedimentation, membrane technologic, ion exchange, and reverse osmosis. for low heavy metal concentrations, these techniques inefficient in certain cases and have high capital and operational cost [5]. the adsorption process can be an attractive alternative method for the removal of heavy metals [6]. some adsorbents can adsorb a wide range of heavy metals, whereas others are specific for certain types of metals [7]. the application of adsorption in environmental treatment has become a significant research area in recent years [8, 9, and 10]. many researchers used agricultural wastes for removal of heavy metal ions such as raw orange peel[11], modified sugarcane bagasse [12], modified oak sawdust [13],modified lignin[14],wood and bark residues[15], peanut hull [16,17] , dehydrated wheat bran[18],maize leaf [19], bean pee [20], tobacco leaves [21], banana and orange peels [22], coconut husk[23], charcoal [24], modified sugar beet pulp[25],modified cellulosic materials[26], modified corncob[27]. although, the date pits have been demonstrated as an adsorbent for heavy metal ions, the calibration of the best operating conditions for the adsorption of cu 2+ , ni 2+ , and zn 2+ from aqueous solution using al-zahid date pits were not fully investigated. saad et al [28] stated that the date pits adsorbent offers a unique advantage in rapid preconcentration and recovery of uo2 2+ from dilute aqueous solution at ph 6–7.5 by flow mode of separation. also, al-ghouti et al [29] demonstrated the potential of date pits for adsorbing methylene blue, cu 2+ , and cd 2+ to provide fundamental information for studying equilibrium adsorption isotherms and adsorption mechanism. bouhamed et al [30] indicated that the prepared activated carbon from date stones for removal of cu 2+ , zn 2+ , and ni 2+ ions from an aqueous mixture was suitable for the removal of metal ions present in a multicomponent system in contaminated wastewater. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:dr.khalid.hummadi@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2021.2.4 k. k. hummadi / iraqi journal of chemical and petroleum engineering 22,2 (2021) 27 35 28 zainab mahdi, et al. [31] used the date seed biochar for removal of pb 2+ , cu 2+ , and ni 2+ ions from binary and ternary systems. in this work, al-zahdi date pits, an agricultural waste generated from food processing and jams production, were used as adsorbent material to remove cu 2+ , ni 2+ , and zn 2+ from an aqueous solution. the influence of operating conditions on the removal of heavy metals was studied to predict the best conditions which help us to improve and develop the efficiency of this process. 2experimental work. 2.1. raw materials an agricultural solid waste (al-zahdi iraqi date pits), de-ionized distill water, cuso4. 5h2o, ni (no3)2.6h2o, znso4. 7h2o, hcl, and naoh, with high purity of more than 99 percent, were purchased from sigma aldrich and used in this work. 2.2. prepare the adsorbent and aqueous solutions the date pits were washed several times with deionized water and left in the open air for several days and then they were transferred to the oven at 80 o c until dryness. the adsorbent was crushed, milled, and sieving into a different particle size of, 1500, 1000, 500, and 200 µm. the standard stock of heavy metals aqueous solutions of cu 2+ , zn 2+ , and ni 2+ (1000 ppm) were prepared by dissolve cuso4. 5h2o, ni (no3)2.6h2o, and znso4. 7h2o salt in a certain amount of deionized distilled water. the standard solution of heavy metals was diluted to achieve standard concentrations of 10, 35, 60, 85, and 110 ppm of heavy metals. 3experimental work 3.1. effect of the adsorbent dosage date pits of 200µm mixed heavy metals (cu 2+ , zn 2+ , and ni 2+ ) solution with dose of 0.04, 0.08, 0.1, 0.12, 0.16, 0.2, and 0.3 g /ml were put in the bottles of 250ml. the ph (6 ±0.2) was adjusted by 1m hcl or 1m naoh. the samples were agitated by a shaker (kottermann, germen) at 250 rpm at room temperature (25± 2 o c) until equilibrium. then the adsorbent was separated by filtration through 0.45µm of cellulose nitrate membrane. the heavy metal concentrations in the remaining solution were analyzed by using an absorption spectrophotometer (spectro aa 10). the uptake capacity (qe) (mg/g) of heavy metals was calculated by using the eq. (1): qe = (cai caeq) vsol/ wd ) (1) where cai and caeq represent the initial heavy metal and equilibrium concentration respectively. vsol is the volume of solution and wd is the weight of date pits used. 3.2. effect of particle size the different particle sizes of date pits (1500, 1000, 500, and 200 µm) were mixed with heavy metals solution (60ppm) with an adsorbent dose of 0.12g/ml and ph 6 ±0.2. the mixtures were agitated (250 rpm) at room temperature (25 ± 2 o c) until equilibrium, and then the adsorbent was separated and analyzed for the remaining concentration. 3.3. effect of shaking speed date pits of a particle size of 200µm were added to the heavy metal solution (60 ppm) to adsorbent dose of 0.12 g/ml and ph 6 ±0.2. the mixtures were agitated for different speeds (150, 200, 250, 300, 350, and 400 rpm) at room temperature (25±2 o c) until equilibrium then the adsorbent was separated and analyzed for the remaining concentration. 3.4. effect of ph of solution heavy metals solution of 60 ppm with different ph ranges from 2 to 12 was prepared. the adjustment of ph solutions to the appropriate value was conducted by adding either 1m hcl or 1m naoh. the date pits of 200 µm were added to these solutions with an adsorbent dose of 0.12 g/ml. the samples were agitated (300 rpm) at room temperature (25 ± 2 o c) until equilibrium. the adsorbent was separated from samples and the remaining solution was analyzed. 3.5. effect of temperature. heavy metal solutions of different initial concentrations range from 10 to 110 ppm were mixed with date pits of 200µm with an adsorbent dose of 0.12 g/ml at ph 5.5 ±0.2. then the mixtures were agitated (300 rpm) at different temperatures (25, 35, 45, and 55 ±2 o c) until equilibrium. the remainder solutions were analyzed. 3.6. kinetic experiments a certain amount of adsorbent of 200µm was added to the heavy metal solution of different concentrations (10, 35, 60, 85, and 110 ppm) and ph 5.5 ±0.2 with an adsorbent dose of 0.12 g /ml. the mixtures were agitated by shaker at 300 rpm at room temperature (25 ± 2 o c). then the samples were taken periodically for analysis to study the dynamic of adsorption of heavy metals by date pits process. 4result and discussion 4.1. effect of the adsorbent concentration fig. 1 presents the effect of date pits dose on the heavy metals uptake capacity at constant other conditions until equilibrium. k. k. hummadi / iraqi journal of chemical and petroleum engineering 22,2 (2021) 27 35 29 the heavy metals uptake increases with increasing the adsorbent dose to 0.12g/ml of heavy metals solution value and then decreases with increasing the adsorbent dose. this is due to increase the contact surface area and the active adsorption sites with increasing the adsorbent dose [13]. further increase in the adsorbent dose may cause agglomeration of particles which affects reducing the adsorption efficiency of heavy metals [18]. 4.2. effect of the particle size the effect of particle size of date pits on the uptake capacity of heavy metals from aqueous solution is shown in fig. 2. while fig. 3 shows the copper uptake capacity against the initial concentration of heavy metal in the solution for different particle sizes of date pits at constant operating conditions(adsorbent dose 0.12g/ml, ph=6,250 rpm, and 25 o c) until equilibrium. as shown in figs 2 and 3, the heavy metals uptake capacity increases with decreasing the particle size of the adsorbent. fig. 4 presents the sem micrographs for the raw date pits before (4a) and after (4b) adsorption of heavy metals respectively. the raw date pit has numerous pores and channels on the surface. this is a positive for the ability of date pits to be a good surface for adsorption of heavy metals from aqueous solution as shown in fig4b. the raw date pit has porosity on the surface and many channels between the particles of date pit material. when decreasing the particle size during the crushing and grinding process, the sealed channels were opened in the adsorbent, and that increase in the surface area and the active sits of the adsorbent which then becomes available for adsorption, therefore the increase of heavy metals uptake capacity. fig. 1. heavy metals adsorption capacity vs. adsorbent dose fig. 2. heavy metals adsorption capacity vs. particle size of date pits fig. 3. heavy metals adsorption capacity vs. initial concentration of copper in the solution for different particle size of date pits (a) (b) fig. 4. sem micrographs for the raw date pits of date pits (a) and after adsorption of heavy metals (b) k. k. hummadi / iraqi journal of chemical and petroleum engineering 22,2 (2021) 27 35 30 4.3. effect of shaking speed fig. 5 shows the effect of shaking speed on the removal of heavy metals aqueous solution of 60 ppm with constant operating conditions (adsorbent dose 0.12 g/ml, ph 6 at room temperature, and adsorbent particle size of 200µm) until equilibrium. the results show that the heavy metals uptake capacity increased with increasing the speed of shaking up to 300 rpm and then decreased when the shaking speed increased above 300 rpm. at high shaking speed, the mass transfer resistance was decreased. further increase in shaking rate may desorb the heavy metal ions from the adsorbent. therefore it could conclude that a shaking rate of 300 rpm of agitated speed was sufficient to obtain better adsorption. fig. 5. heavy metals adsorption capacity vs. shaking speed 4.4. effect of initial ph of solution fig. 6 shows the uptake capacity of the heavy metals onto date pits with constant operating conditions (adsorbent dose 0.12g/ml, initial heavy metal solution of 60 ppm, adsorbent particle size of 200 µm at room temperature and shaking speed of 300 rpm) for different ph solution. the results show that adsorption capacity of heavy metals increased with increasing the ph of solution up to 5.5 and then decreased with increasing the ph above this value. this is attributed to that the high concentration of h + ions in acidic solution and they make a competition with heavy metals on the active sits onto the surface of the adsorbent. özer et al [18] stated that at low ph values, the surface of adsorbent would be surrounded by hydronium ions (h3o + ), which decrease the copper interaction with binding sites of the adsorbent. this is hindering the access of metal ions by greater repulsive forces. while above ph of 5.5, maybe occurring the precipitated components as a result of reacted the oh ions with the heavy metal ions [12, 32]. özer a. et al [18] and quek et al [33] demonstrated that the critical ph value was 5 for removal of copper onto dehydrated wheat bran and sago waste respectively. fig. 6. heavy metals adsorption capacity vs. ph of the solution 4.5. effect of initial concentration and adsorption time the effect of initial concentration of heavy metals and time of adsorption on the uptake capacity of cu 2+ , zn 2+ , and ni 2+ is shown in fig. 7, fig. 8, and 9 respectively, at constant operating conditions(adsorbent dose 0.12g, adsorbent particle size of 200 μm, ph 5.5, 300 rpm of shaking speed). these figures show that the adsorption capacity of heavy metals increased with increasing the initial metal concentration of heavy metals as a result of increase the driving force of mass transfer. above initial concentration of 85 ppm of heavy metals, increasing the removal efficiency of metals was insignificant as a result of saturated active sits on the date pits. it could be seen that the larger uptake capacity of cu 2+ , zn 2+ , and ni 2+ occurred at 72 h of adsorption time, and then the efficiency of metal adsorption becomes constant with increasing the adsorption time. this is attributed to that the adsorbent reached to saturate with heavy metals. increasing the shaking speed to the optimum value of 300 rpm is sufficient to assure the reduction in the boundary layer around the surface of the particles, then the effect of external film diffusion assumed not significant as mentioned previously in sec. (4.3). eq. (2) was used to state the role of intraparticle diffusion. qt = kd t 1/2 + c (2) [34] where qt is the adsorption capacity of metal (mg/g), kd is the initial rate of diffusion (mg l −1 min −1/2 ), and c is constant of intercept. figs 10, 11, and 12 show the cu 2+ , zn 2+ and ni 2+ uptake capacity versus the square root of the adsorption time respectively for different initial concentrations of heavy metals in the solution. most of data represented by straight lines but these data did not pass through the origin point. therefore according to weber and marries [35], intracore diffusion was involved in the adsorption process but is not the controlling step. k. k. hummadi / iraqi journal of chemical and petroleum engineering 22,2 (2021) 27 35 31 fig. 7. copper adsorption capacity vs. time of adsorption with several of copper concentration fig. 8. zinc adsorption capacity vs. time of adsorption with several of zinc concentration fig. 9. nickle adsorption capacity vs. time of adsorption with several of nickle concentration fig. 10. copper adsorption capacity vs. time square of adsorption fig. 11. zinc adsorption capacity vs. time square of adsorption fig. 12. nickle adsorption capacity vs. time square of adsorption k. k. hummadi / iraqi journal of chemical and petroleum engineering 22,2 (2021) 27 35 32 4.6. adsorption isotherm equilibrium studies gave the capacity of the adsorbent for adsorption [36]. many researchers have shown that the concentration of the adsorbent is usually proportional exponentially to the concentration that remains unabsorbed. the langmuir equation 3 [37] and freundlich equation 4 [38] are given by. qe=qm k ce/(1+kce) (3) qe =kf ce 1/n (4) where qm is the maximum adsorption capacity (mg/g), k is the fitting parameter, ce is the concentration of the heavy metal in solution at equilibrium (mg/l), qe is the uptake capacity (mg/g), while kf and n are the freundlich constants which are empirical constants depending on several environmental factors and. kf and n indicate how favorable the adsorption process. the maximum adsorption capacity according to the langmuir equation was 0.21, 0.149, 0.132 mmol/g for cu 2+ , zn 2+ , and ni 2+ respectively. these results are in agreement with the previous study for the removal of heavy metals onto raw date pits and prepared activated carbon from date pits. bouhamed et al.[30]stated that the maximum adsorption capacity was 0.29, 0.18,and 0.27 mmol/g for cu 2+ , zn 2+ , and ni 2+ using prepared activated carbon from date pits in ternary mixture and them was 0.49, 0.33,and 0.27mmol/g[39,40] in single metal system respectively. banat et al. [41] found that the adsorption capacity for non-activated date pits towards cu and zn was 0.15 and 0.09 mmol/g respectively. therefore, the date pits without any pretreatment could be used as an effective adsorbent for adsorption of heavy metals from an aqueous solution. the isotherm experimental data follow the freundlich model very well with the values of r 2 (0.866-0.921) as shown in table 1. the freundlich constants for the removal of metals in comparison with other results using different adsorbent for the same metals are given in table 1. from table 1 it could be seen that the kf and 1/n values of cu 2+ are higher than that of zn 2+ and that of ni 2+ . this is indicated to that the adsorption capacity and adsorption intensity for copper removal was the highest as shown in figures 7, 8, and 9. the adsorption capacity of cu +2 is higher than for zn +2 and ni +2 . this result is in agreement with the results of al-ghuoti et al [29] and banat et al [42]. banat et al explained that this behavior is based on ionic radii. 4.6. effect of temperature fig. 13 shows the heavy metal adsorption capacity versus different adsorption temperatures for various initial concentrations of heavy metal with ph 5.5 by using 0.12g of date pits (200 µm) /ml of solution for 72 h of mixing time. the adsorption capacity of heavy metal ions decreased with increasing temperatures, thereby demonstrating the exothermic nature of the bioadsorption process. this is in agreement with the finding of al-asheh and duvnjak [43]. table (1) freundlich constants for adsorption of cu 2+ , zn 2+ and ni 2+ for different adsorbents. reference sorbent r 2 1/n kf metal viraraghavan and dronamraju[44] mullen et al [45] de rome and gadd [46] banat et al.[41] bouhamed et al[30] this work peat a. niger c. resinae data pits ac date pits * ac date pits * date pits 0.898 0.956 --- 0.9939 0.999 0.96 0.866 0.895 0.894 0.6 1.2979 1.377 0.69 0.606 0.0002 1.035 3.467 2.5653 1.769 0.6 0.529 cu 2+ viraraghavan and dronamnyu[44] banat et al.[41] bouhamed et al[30] this work peat data pits ac date pits * ac date pits * date pits 0.885 0.9973 0.9921 0.95 0.912 0.771 0.3268 0.412 0.74 0.711 0.0001 0.0781 0.069 0.32 0.2374 zn 2+ viraragha van and dronamrajn[44] bouhamed et al[30] this work peat ac date pits * date pits 0.907 0.98 0.846 0.565 0.7 0.608 0.0001 0.46 0.1739 ni 2+ *(ac) prepared activated carbone. fig. 13. heavy metals adsorption capacity vs. temperature of adsorption 5conclusion the results clearly showed that the study of the operating parameters is essential for finding the best conditions and all of these parameters affected the removal efficiency of heavy metals from an aqueous solution. from this work, it could be concluded that the best adsorbent dose was 0.12g of date pits/ml of solution. the adsorption capacity of heavy metals increases with decreasing the adsorbent particle size while the reduction of particle size has a little effect on the removal of heavy metals at a low initial concentration of heavy metals in the solution. k. k. hummadi / iraqi journal of chemical and petroleum engineering 22,2 (2021) 27 35 33 while at a higher concentration of heavy metals an effect was observed. the experimental work indicated that the increases in the shaking speed results increase in the efficiency of heavy metals removal until up to 300 rpm of shaking speed for 72 h and then decreases with an increase above that. the critical ph of the solution was 5±0.2 and below or above this value of ph, the adsorption capacity of heavy metal ions is decreased. the efficiency of removal of heavy metals decreased when the concentration of the initial metals became greater than 85 ppm. the maximum adsorption capacity according to the langmuir equation was 0.21, 0.149, 0.132 mmol/g for cu 2+ , zn 2+ , and ni 2+ respectively. the adsorption of heavy metals onto al-zahdi iraqi date pits was an exothermic process and the adsorption equilibrium was well described by the freundlich model. reference . [1] demirbas,a.,heavy metal adsorption onto agro-based waste materials: a review, j. hazard. mater. 157(2008) 220–229. [2] al-degs, y.s. ; el-barghouthi, m.i. ; issa, a.a. ; khraisheh, m.a. ; walker, g.m. ,sorption of zn(ii), pb(ii), and co(ii) using natural sorbents: equilibrium and kinetic studies, water res. 40 (2006) 2645–2658. [3] an, h.k. ; park, b.y. ; kim, d.s. , crab shell for the removal of heavy metals from aqueous solution, water res. 35 (2001) 3551–3556. [4] van der leeden m.c., troise , f.l. and todd , dik , the water encyclopedia , second edition , lewis publishers , michigan (1990). [5] chaiyasith, s.; chaiyasith, p.; septhu, c., removal of cadmium and nickel from aqueous solution by adsorption onto treated fly ash from thailand, thammasat. int. j. sci. technol., 1l (2006) 13–20. [6] hasan, sh. ; ghosh, t.k. ; viswanath, d.s. ; boddu, v.m. ,dispersion of chitosan on perlite for enhancement of copper(ii) adsorption capacity, j. hazard. mater. 152 (2008) 826–837. [7] vieira,r.h.s.f.;volesky,b., biosorption:asolution to pollution , internatl microbiol,3(2000) 17-24. [8] hakan çelebi, güldengök , oğuzhangök, adsorption capability of brewed tea waste in waters containing toxic lead(ii), cadmium (ii), nickel (ii), and zinc(ii) heavy metal ions, environmental engineering, 10:17570 (2020) 1-12. [9] eman a.assirey, shadia m. sirry , hayfaa. burkani , medhata. ibrahim, modifed ziziphus spina christi stones as green route for the removal of heavy metals, scientifc reports,10:20557 (2020) 1-10. [10] chiranjit bhattacharjee∗ , suman dutta, vinod k. saxena, a review on biosorptive removal of dyes and heavy metals from wastewater using watermelon rind as biosorbent, environmental advances 2, 100007 (2020) 1-13. [11] liang,s.; guo, x.; feng, n.; tian, q, , isotherms, kinetics and thermodynamic studies of adsorption of cu2+ from aqueous solutions by mg2+/k+ type orange peel adsorbents, j hazard mater., 174(2010) 756-762. [12] homagai p.l., ghimire k.n.; inoue k., adsorption behavior of heavy metals onto chemically modified sugarcane bagasse, bioresource tech.101 (2010) 2067-2069. [13] argun,m.e.; dursun,s.; ozdemir,c.; karatas,m., heavy metal adsorption by modified oak sawdust: thermodynamics and kinetics, j. hazard. mater. 141(2007) 77-85. [14] demirbas, a.,adsorption of co(ii) and hg(ii) from water and wastewater onto modified lignin, energy sour. part a 29 (2007) 117–123. [15] kmiecik, p., lyons, a.s. ; whıte, i.; brown, l.k. ; rowell, r.m. , use of wood and bark residues to remove copper ions from water, biuletyn informacyjny no. 1–2 (2005) 75–78. [16] hashem, a., abdel-halim, e.s. ; el-tahlawy, kh.f. ; hebeish, a., enhancement of adsorption of co (ii) and ni (ii) ions onto peanut hulls though esterification using citric acid, adsorp. sci. technol. 23 (2005) 367–380. [17] johnson, p.d. ; watson, m.a. ; brown, j.; jefcoat, i.a. ,peanut hull pellets as a single use sorbent for the capture of cu(ii) from wastewater, waste manage. 22 (2002) 471–480. [18] özer,a.; özer,d.; özer,ay., the adsorption of copper(ii) ions on to dehydrated wheat bran (dwb):determination of the equilibrium and thermodynamic parameters,proc.bioch.,93(2004) 2183-2191. [19] ahalya, n.; ramachandra, t.v. ; kanamadi, r.d. , biosorption of heavy metals, res. j. chem. environ. 7 (2003) 71–79. [20] jenan a. al-najar, removal of dyes from synthetic wastewater by agricultural waste, iraqi journal of chemical and petroleum engineering, vol.18no.3(september2017) 31-48. [21] tamara kawther hussein, comparative study for removal of zn+2 ions from aqueous solutions by adsorption and forward osmosis, iraqi journal of chemical and petroleum engineering, vol.18 no.2 (june 2017) 125 – 138. [22] annadurai, g.; juang, r.s. ; lee, d.l. ,adsorption of heavy metals from water using banana and orange peels, water sci. technol. 47 (2002) 185– 190. [23] babarinde,n.a.a.,adsorption of zinc(ii) and cadimium(ii) by coconut husk and goat hair,j.pure appl.sci.,5(2002) 81-85. [24] dakiky, m.; khamis, m.; manassra, a.; mer’eb, m., selective adsorption of chromium(vi) in industrial wastewater using low-cost abundantly available adsorbents, adv. environ. res. 6 (2002) 533–561. https://www.sciencedirect.com/science/article/abs/pii/s0304389408000629 https://www.sciencedirect.com/science/article/abs/pii/s0304389408000629 https://www.sciencedirect.com/science/article/abs/pii/s0304389408000629 https://www.sciencedirect.com/science/article/abs/pii/s0043135406003022 https://www.sciencedirect.com/science/article/abs/pii/s0043135406003022 https://www.sciencedirect.com/science/article/abs/pii/s0043135406003022 https://www.sciencedirect.com/science/article/abs/pii/s0043135406003022 https://www.sciencedirect.com/science/article/abs/pii/s0043135401000999 https://www.sciencedirect.com/science/article/abs/pii/s0043135401000999 https://www.sciencedirect.com/science/article/abs/pii/s0043135401000999 https://books.google.iq/books?hl=en&lr=&id=byie-6bei1oc&oi=fnd&pg=pa2&dq=the+water+encyclopedia&ots=nudvdmr-_m&sig=oed-fdhoy1auxboninwnkbryxt4&redir_esc=y#v=onepage&q=the%20water%20encyclopedia&f=false https://books.google.iq/books?hl=en&lr=&id=byie-6bei1oc&oi=fnd&pg=pa2&dq=the+water+encyclopedia&ots=nudvdmr-_m&sig=oed-fdhoy1auxboninwnkbryxt4&redir_esc=y#v=onepage&q=the%20water%20encyclopedia&f=false https://books.google.iq/books?hl=en&lr=&id=byie-6bei1oc&oi=fnd&pg=pa2&dq=the+water+encyclopedia&ots=nudvdmr-_m&sig=oed-fdhoy1auxboninwnkbryxt4&redir_esc=y#v=onepage&q=the%20water%20encyclopedia&f=false https://ph02.tci-thaijo.org/index.php/scitechasia/article/download/41548/34335 https://ph02.tci-thaijo.org/index.php/scitechasia/article/download/41548/34335 https://ph02.tci-thaijo.org/index.php/scitechasia/article/download/41548/34335 https://ph02.tci-thaijo.org/index.php/scitechasia/article/download/41548/34335 https://www.sciencedirect.com/science/article/abs/pii/s0304389407010813 https://www.sciencedirect.com/science/article/abs/pii/s0304389407010813 https://www.sciencedirect.com/science/article/abs/pii/s0304389407010813 https://www.sciencedirect.com/science/article/abs/pii/s0304389407010813 https://www.nature.com/articles/s41598-020-74553-4 https://www.nature.com/articles/s41598-020-74553-4 https://www.nature.com/articles/s41598-020-74553-4 https://www.nature.com/articles/s41598-020-74553-4 https://www.nature.com/articles/s41598-020-74553-4 https://www.nature.com/articles/s41598-020-76810-y https://www.nature.com/articles/s41598-020-76810-y https://www.nature.com/articles/s41598-020-76810-y https://www.nature.com/articles/s41598-020-76810-y https://www.sciencedirect.com/science/article/pii/s2666765720300077 https://www.sciencedirect.com/science/article/pii/s2666765720300077 https://www.sciencedirect.com/science/article/pii/s2666765720300077 https://www.sciencedirect.com/science/article/pii/s2666765720300077 https://www.sciencedirect.com/science/article/pii/s2666765720300077 https://www.sciencedirect.com/science/article/abs/pii/s0304389409015775 https://www.sciencedirect.com/science/article/abs/pii/s0304389409015775 https://www.sciencedirect.com/science/article/abs/pii/s0304389409015775 https://www.sciencedirect.com/science/article/abs/pii/s0304389409015775 https://www.sciencedirect.com/science/article/abs/pii/s0304389409015775 https://www.sciencedirect.com/science/article/abs/pii/s0960852409015788 https://www.sciencedirect.com/science/article/abs/pii/s0960852409015788 https://www.sciencedirect.com/science/article/abs/pii/s0960852409015788 https://www.sciencedirect.com/science/article/abs/pii/s0960852409015788 https://www.sciencedirect.com/science/article/abs/pii/s030438940600762x https://www.sciencedirect.com/science/article/abs/pii/s030438940600762x https://www.sciencedirect.com/science/article/abs/pii/s030438940600762x https://www.sciencedirect.com/science/article/abs/pii/s030438940600762x https://www.tandfonline.com/doi/abs/10.1080/009083190948720 https://www.tandfonline.com/doi/abs/10.1080/009083190948720 https://www.tandfonline.com/doi/abs/10.1080/009083190948720 https://journals.sagepub.com/doi/abs/10.1260/026361705774355478 https://journals.sagepub.com/doi/abs/10.1260/026361705774355478 https://journals.sagepub.com/doi/abs/10.1260/026361705774355478 https://journals.sagepub.com/doi/abs/10.1260/026361705774355478 https://journals.sagepub.com/doi/abs/10.1260/026361705774355478 https://www.sciencedirect.com/science/article/abs/pii/s0956053x01000368 https://www.sciencedirect.com/science/article/abs/pii/s0956053x01000368 https://www.sciencedirect.com/science/article/abs/pii/s0956053x01000368 https://www.sciencedirect.com/science/article/abs/pii/s0956053x01000368 https://www.sciencedirect.com/science/article/pii/s0032959203004308 https://www.sciencedirect.com/science/article/pii/s0032959203004308 https://www.sciencedirect.com/science/article/pii/s0032959203004308 https://www.sciencedirect.com/science/article/pii/s0032959203004308 https://www.sciencedirect.com/science/article/pii/s0032959203004308 https://www.researchgate.net/publication/257029311_biosorption_of_heavy_metals https://www.researchgate.net/publication/257029311_biosorption_of_heavy_metals https://www.researchgate.net/publication/257029311_biosorption_of_heavy_metals https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/64 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/64 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/64 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/64 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/208 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/208 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/208 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/208 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/208 https://iwaponline.com/wst/article-abstract/47/1/185/10681/adsorption-of-heavy-metals-from-water-using-banana https://iwaponline.com/wst/article-abstract/47/1/185/10681/adsorption-of-heavy-metals-from-water-using-banana https://iwaponline.com/wst/article-abstract/47/1/185/10681/adsorption-of-heavy-metals-from-water-using-banana https://iwaponline.com/wst/article-abstract/47/1/185/10681/adsorption-of-heavy-metals-from-water-using-banana https://www.sid.ir/en/journal/viewpaper.aspx?id=328416 https://www.sid.ir/en/journal/viewpaper.aspx?id=328416 https://www.sid.ir/en/journal/viewpaper.aspx?id=328416 https://www.sciencedirect.com/science/article/abs/pii/s109301910100079x https://www.sciencedirect.com/science/article/abs/pii/s109301910100079x https://www.sciencedirect.com/science/article/abs/pii/s109301910100079x https://www.sciencedirect.com/science/article/abs/pii/s109301910100079x https://www.sciencedirect.com/science/article/abs/pii/s109301910100079x k. k. hummadi / iraqi journal of chemical and petroleum engineering 22,2 (2021) 27 35 34 [25] reddad, z.; gerente, c.; andres, y. ; ralet, m.c. ;. thibault, j.-f; cloirec, p.l. ,ni(ii) and cu(ii) binding properties of native and modified sugar beet pulp, carbohyd. polym. 49 (2002) 23–31. [26] acemıoglu, b.; alma, m.h., equilibrium studies on the adsorption of cu(ii) from aqueous solution onto cellulose, j. colloid interface sci. 243 (2001) 81-83. [27] vaughan, t.; seo, c.w.; marshall, w.e, removal of selected metal ions from aqueous solution using modified corncobs, biores. technol. 78 (2001) 133–139. [28] saad, e.m. ; mansour, r.a. ; el-asmy, a. , elshahawi, m.s. ,sorption profile and chromatographic separation of uranium (vi) ions from aqueous solutions onto date pits solid sorbent, talanta 76 (2008) 1041–1046. [29] al-ghoutia m.a.;li j.,salamh y.; al-laqtah n.; walker g.; ahmad m. n. m., adsorption mechanisms of removing heavy metals and dyes from aqueous solution using date pits solid adsorbent, j. hazard. mater. 176(2010) 510-520. [30] bouhamed,f.; z. elouear; j. bouzid;b. ouddane, multi-component adsorption of copper, nickel and zinc from aqueous solutions onto activated carbon prepared from date stones, environ sci pollut res,april(2015)1-6. [31] zainab mahdi; qiming jimmy yu ;ali el hanandeh, competitive adsorption of heavy metal ions (pb2+ , cu2+, and ni2+) onto date seed biochar: batch and fixed bed experiments, separation science and technology,(2018) [32] oconnell,d.w.;birkinshaw,c.;o,dwyer,t.f.,he avy metal adsorbents prepared from the modificationof cellulose:a review,bioreso.tech.,99(2008) 6709-6724. [33] quek sy, wase daj, foster cf, the use of sago waste for the sorption of lead and copper. water s a. 24(3) (1998) 251 – 256. [34] mckay, g.,the adsorption of basic dye onto silica from aqueous solution—solid diffusion model, chem. eng. sci. 39 (1984) 129–138. [35] weber, w.j, jr. and morris, j.c.,kinetics of adsorption on carbon from solution, j.sanit. eng. div. am. soc. civ. eng., 89 (1963) 31 -39. [36] ho,y.s., "adsorption of heavy metals from waste streams by natural materials" ,phd thesis, the university of birmingham ,uk. (1995). [37] futalan cm, kan cc, dalida ml, hsien kj, pascua c, wan mw ,comparative and competitive adsorption of copper, lead, and nickel using chitosan immobilized on entonite. carbohydr polym 83((2011) 528–536 [38] freundlich ,h. “adsorption in solution,” physical chemistry, 57, (1906) 384–410. [39] bouhamed f, elouear z, bouzid j, adsorptive removal of copper (ii) from aqueous solutions on activated carbon prepared from tunisian date stones: equilibrium kinetics and thermodynamics. j taiwan inst chem eng 43(2012) 741–749 [40] bouhamed f, elouear z, bouzid j, ouddane b ,application of activated carbon based on a tunisian date stons for the ni(ii) and zn(ii) adsoption in single and binary systems. fresenius environ bull 22(2013) 3490–3500. [41] banat, f.; al-asheh, s ,al-rousan,d.,a comparative study of copper and zinc ion adsorption on to activated an non activated date pite,adsorption since and technology,vol 20,no 4(2002) 319-335. [42] banat, f.; al-asheh, s.; al-makhadmeh, l., utilization of raw and activated date pits for the removal of phenol from aqueous solutions, chem. eng. technol. 27 (2004) 80–86. [43] al-asheh , s. ;duvnjak. z, adsorption of copper and chromium by aspergillus-carbonarius , biotechnol. prog. , 11(1995) 638643. [44] viraraghavan, t. and dronamraju, m. m., removal of copper, nickel and zinc from wastewater by adsorption using feat , journal of environmental science and health.part a: environmental science and engineering and toxicology: toxic/hazardous substances and environmental engineering, 28:6(1993) 1261-1276. [45] mullen, m.d.; d.c.wolf; t.j.beveridge; g.w.bailey., sorption of heavy metals by the soil fungi aspergillus niger and mucor rouxii, soil biology and biochemistry, vol. 24, issue 2, february( 1992) 129-135. [46] louise de rome and geoffrey m. gadd, copper adsorption by rhizopus arrhizus, cladosporium resinae and penicillium italicum, applied microbiology and biotechnology, vol 26 (1987) 84– 90. https://www.sciencedirect.com/science/article/abs/pii/s0144861701003010 https://www.sciencedirect.com/science/article/abs/pii/s0144861701003010 https://www.sciencedirect.com/science/article/abs/pii/s0144861701003010 https://www.sciencedirect.com/science/article/abs/pii/s0144861701003010 https://www.sciencedirect.com/science/article/abs/pii/s0021979701978737 https://www.sciencedirect.com/science/article/abs/pii/s0021979701978737 https://www.sciencedirect.com/science/article/abs/pii/s0021979701978737 https://www.sciencedirect.com/science/article/abs/pii/s0021979701978737 https://www.sciencedirect.com/science/article/abs/pii/s0960852401000074 https://www.sciencedirect.com/science/article/abs/pii/s0960852401000074 https://www.sciencedirect.com/science/article/abs/pii/s0960852401000074 https://www.sciencedirect.com/science/article/abs/pii/s0960852401000074 https://www.sciencedirect.com/science/article/abs/pii/s0039914008003500 https://www.sciencedirect.com/science/article/abs/pii/s0039914008003500 https://www.sciencedirect.com/science/article/abs/pii/s0039914008003500 https://www.sciencedirect.com/science/article/abs/pii/s0039914008003500 https://www.sciencedirect.com/science/article/abs/pii/s0039914008003500 https://www.sciencedirect.com/science/article/abs/pii/s0304389409018433 https://www.sciencedirect.com/science/article/abs/pii/s0304389409018433 https://www.sciencedirect.com/science/article/abs/pii/s0304389409018433 https://www.sciencedirect.com/science/article/abs/pii/s0304389409018433 https://www.sciencedirect.com/science/article/abs/pii/s0304389409018433 https://link.springer.com/article/10.1007/s11356-015-4400-3 https://link.springer.com/article/10.1007/s11356-015-4400-3 https://link.springer.com/article/10.1007/s11356-015-4400-3 https://link.springer.com/article/10.1007/s11356-015-4400-3 https://link.springer.com/article/10.1007/s11356-015-4400-3 https://www.tandfonline.com/doi/abs/10.1080/01496395.2018.1523192 https://www.tandfonline.com/doi/abs/10.1080/01496395.2018.1523192 https://www.tandfonline.com/doi/abs/10.1080/01496395.2018.1523192 https://www.tandfonline.com/doi/abs/10.1080/01496395.2018.1523192 https://www.tandfonline.com/doi/abs/10.1080/01496395.2018.1523192 https://www.tandfonline.com/doi/abs/10.1080/01496395.2018.1523192 https://www.sciencedirect.com/science/article/abs/pii/s0960852408000710 https://www.sciencedirect.com/science/article/abs/pii/s0960852408000710 https://www.sciencedirect.com/science/article/abs/pii/s0960852408000710 https://www.sciencedirect.com/science/article/abs/pii/s0960852408000710 http://www.wrc.org.za/wp-content/uploads/mdocs/watersa_1998_03_jul98_p251.pdf http://www.wrc.org.za/wp-content/uploads/mdocs/watersa_1998_03_jul98_p251.pdf http://www.wrc.org.za/wp-content/uploads/mdocs/watersa_1998_03_jul98_p251.pdf https://www.sciencedirect.com/science/article/pii/0009250984801384 https://www.sciencedirect.com/science/article/pii/0009250984801384 https://www.sciencedirect.com/science/article/pii/0009250984801384 https://ascelibrary.org/doi/abs/10.1061/jsedai.0000430 https://ascelibrary.org/doi/abs/10.1061/jsedai.0000430 https://ascelibrary.org/doi/abs/10.1061/jsedai.0000430 https://www.sciencedirect.com/science/article/abs/pii/s0144861710006338 https://www.sciencedirect.com/science/article/abs/pii/s0144861710006338 https://www.sciencedirect.com/science/article/abs/pii/s0144861710006338 https://www.sciencedirect.com/science/article/abs/pii/s0144861710006338 https://www.sciencedirect.com/science/article/abs/pii/s0144861710006338 https://www.sciencedirect.com/science/article/abs/pii/s1876107012000387 https://www.sciencedirect.com/science/article/abs/pii/s1876107012000387 https://www.sciencedirect.com/science/article/abs/pii/s1876107012000387 https://www.sciencedirect.com/science/article/abs/pii/s1876107012000387 https://www.sciencedirect.com/science/article/abs/pii/s1876107012000387 https://www.researchgate.net/profile/zouheir-elouaer/publication/258994782_application_of_activated_carbon_based_on_a_tunisian_date_stones_for_the_ni_ii_and_zn_ii_adsorption_in_single_and_binary_systems/links/00b7d52aafca37948d000000/application-of-activated-carbon-based-on-a-tunisian-date-stones-for-the-ni-ii-and-zn-ii-adsorption-in-single-and-binary-systems.pdf https://www.researchgate.net/profile/zouheir-elouaer/publication/258994782_application_of_activated_carbon_based_on_a_tunisian_date_stones_for_the_ni_ii_and_zn_ii_adsorption_in_single_and_binary_systems/links/00b7d52aafca37948d000000/application-of-activated-carbon-based-on-a-tunisian-date-stones-for-the-ni-ii-and-zn-ii-adsorption-in-single-and-binary-systems.pdf https://www.researchgate.net/profile/zouheir-elouaer/publication/258994782_application_of_activated_carbon_based_on_a_tunisian_date_stones_for_the_ni_ii_and_zn_ii_adsorption_in_single_and_binary_systems/links/00b7d52aafca37948d000000/application-of-activated-carbon-based-on-a-tunisian-date-stones-for-the-ni-ii-and-zn-ii-adsorption-in-single-and-binary-systems.pdf https://www.researchgate.net/profile/zouheir-elouaer/publication/258994782_application_of_activated_carbon_based_on_a_tunisian_date_stones_for_the_ni_ii_and_zn_ii_adsorption_in_single_and_binary_systems/links/00b7d52aafca37948d000000/application-of-activated-carbon-based-on-a-tunisian-date-stones-for-the-ni-ii-and-zn-ii-adsorption-in-single-and-binary-systems.pdf https://www.researchgate.net/profile/zouheir-elouaer/publication/258994782_application_of_activated_carbon_based_on_a_tunisian_date_stones_for_the_ni_ii_and_zn_ii_adsorption_in_single_and_binary_systems/links/00b7d52aafca37948d000000/application-of-activated-carbon-based-on-a-tunisian-date-stones-for-the-ni-ii-and-zn-ii-adsorption-in-single-and-binary-systems.pdf https://journals.sagepub.com/doi/abs/10.1260/02636170260295515 https://journals.sagepub.com/doi/abs/10.1260/02636170260295515 https://journals.sagepub.com/doi/abs/10.1260/02636170260295515 https://journals.sagepub.com/doi/abs/10.1260/02636170260295515 https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.200401868 https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.200401868 https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.200401868 https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.200401868 https://aiche.onlinelibrary.wiley.com/doi/abs/10.1021/bp00036a006 https://aiche.onlinelibrary.wiley.com/doi/abs/10.1021/bp00036a006 https://aiche.onlinelibrary.wiley.com/doi/abs/10.1021/bp00036a006 https://www.tandfonline.com/doi/abs/10.1080/10934529309375941 https://www.tandfonline.com/doi/abs/10.1080/10934529309375941 https://www.tandfonline.com/doi/abs/10.1080/10934529309375941 https://www.tandfonline.com/doi/abs/10.1080/10934529309375941 https://www.tandfonline.com/doi/abs/10.1080/10934529309375941 https://www.tandfonline.com/doi/abs/10.1080/10934529309375941 https://www.tandfonline.com/doi/abs/10.1080/10934529309375941 https://www.sciencedirect.com/science/article/abs/pii/0038071792902683 https://www.sciencedirect.com/science/article/abs/pii/0038071792902683 https://www.sciencedirect.com/science/article/abs/pii/0038071792902683 https://www.sciencedirect.com/science/article/abs/pii/0038071792902683 https://www.sciencedirect.com/science/article/abs/pii/0038071792902683 https://link.springer.com/article/10.1007/bf00282153 https://link.springer.com/article/10.1007/bf00282153 https://link.springer.com/article/10.1007/bf00282153 https://link.springer.com/article/10.1007/bf00282153 https://link.springer.com/article/10.1007/bf00282153 k. k. hummadi / iraqi journal of chemical and petroleum engineering 22,2 (2021) 27 35 35 ألمتزاز المعادن الثقيلة من المحلول المائي باستخدام النفايات الظروف التشغيلية المثلى الزراعية خالد خزعل حمادي جامعة بغداد–كلية الهندسة الخالصة يهدف البحث الى دراسة الظروف التشغيلية المثلى والتي تؤثر على ازالة ايونات النحاس والزنك والنيكل من المحلول المائي باستخدام نوى التمر في تجارب االمتزاز بالدفعات . اشارت النتائج الى ان نوى التمر الزهدي في المحلول ,وزمن امتزاز 0.12g/mlفعال في امتزاز المعادن الثقيلة عند ظروف محددة من الجرعة 72h 300 وسرعة اهتزاز 5.5وحامضيةrpm وصغر الحجم الحبيبي وفي نفس الوقت لوحظ ان الحجم الحبيبي له تاثير قليل على االمتزاز عند التراكيزالواطئة للمعادن الثقيلة . وان االمتزاز يزداد بزيادة التركيز . واكدت النتائج ان امتزاز ppm 85 االمتزاز عند تركيز اعلى من االبتدائي للمعادن بينما تقل كفاءة المعادن القيلة باستخدام نوى التمر الزهدي هي عملية باعثة للحرارة .وان اعلى سعة امتزاز طبقا لمعادلة للنحاس والزنك والنيكل على التوالي.ان معادلة فريدلخ mmol/g 0.132 و 0.149و 0.21النكميور كانت كانت افضل من يمثل امتزاز التوازن وان نتائج ثوابت فريدلخ اشارت الى ان سعة االمتزاز وشدة امتزاز النحاس كانت اكبر من الزنك والنيكل . وان االنتشار داخل الحبيبة كان تاثيره موجود ولكن ليس المسطر على العملية . ن نتائج هذه الدراسة ربما تساعد في ايجاد الظروف المثلى لالمتزاز وتطويرها للعمليات االنتاجية الصناعية وا . المياه الملوثة بالمعادن الثقيلةلتنظيف فرندلخ ,النكميور المياه الملوثة, ,نوى التمر الزهدي : االمتزاز, المعادن الثقيلة,الدالةالكلمات iraqi journal of chemical and petroleum engineering vol.17 no.1 (march 2016) 2136 issn: 1997-4884 corrosion inhibition of low carbon steel in sulfuric acid using polyvinyl alcohol majid i. abdulwahab*, ayad b. ahmed** and aprael s. yaro* *chemical eng. department university of baghdad **medical tech. inst. /al-mansour middle technical university abstract the inhibitive power of polyvinyl alcohol (pva) was investigated toward the corrosion of carbon steel in 0.2n h2so4 solution in the temperature range of 30-60˚c and pva concentration range of 150-2000 ppm. the corrosion rate was measured using both the weight loss and the electrochemical techniques. the weight loss results showed that pva could serve as a corrosion inhibitor but its inhibition power was found to be low for the corrosion of carbon steel in the acidic media. electrochemical analysis of the corrosion process of carbon steel in an electrochemical corrosion cell was investigated using 3-electrode corrosion cell. polarization technique was used for carbon steel corrosion in 0.2n h2so4 solutions in presence and absence of the inhibitor investigated. electrochemical runs were done in the pva concentrations of 150, 1000, and 2000 ppm and temperatures of 30, 40, 50, and 60˚c. it was shown that the inhibition efficiency for pva decreased with increasing temperature at a given pva concentration. on the other hand it was shown that at given temperature the inhibition efficiency of pva was increased with increasing of pva concentration in the corrosive acid until a pva concentration of 2000 ppm was reached. the maximum inhibition efficiency reached was about 71 % at 30ºc and 2000 ppm concentration, calculated by the weight loss technique. it was indicated also that the corrosion of carbon steel in 0.2n h2so4 is highly activation controlled and inhibition action is occurring at both anodic and cathodic sites on the metal surface. key words: carbon steel, corrosion inhibition, sulfuric acid, pva, weight loss, polarization. introduction carbon steel alloys are widely used in most industries for its low cost and availability in case for fabrication of various reaction vessels such as heat exchangers, cooling towers, and pipes [1]. corrosion of metals in contact with acids as in acid cleaning of metal surfaces indicates that the use of inhibitors is necessary [2]. many reports on using organic compounds as potential corrosion inhibitors for metals in acidic media are available [3, 4]. inhibitors especially the organic iraqi journal of chemical and petroleum engineering university of baghdad college of engineering corrosion inhibition of low carbon steel in sulfuric acid using polyvinyl alcohol 22 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net ones work by an adsorption mechanism. the resultant film of inhibitor protects metal by blocking the metal surface from the environment so retarding the electrochemical processes. a number of reviews on the organic inhibitors for metals in different media are available [5, 6]. polymers are used as corrosion inhibitors because; through their functional groups can form complexes with metal ions and on the metal surface, these complexes occupy a large surface area, protecting the metal from corrosive attack. the applications of water-soluble polymers are related to their outstanding properties. the film forming and adhesive qualities enable nearly all water-soluble polymers to find uses as binders, thickeners and adhesives. the use of water-soluble polymers as corrosion inhibitors has attracted considerable attention in recent times due to the fact that they have been shown to be low cost and stable for metallic materials in acidic environment [7,8,9].the application of polyacrylic acid and polyacryl amide as corrosion inhibitors for iron and steel in h2so4 and hcl has been reported [10,11]. other polymers studied to date include poly vinyl imidazoles [9], poly vinyl pyrrolidone, poly ethyl enimine, aliphatic polyamines, and poly vinyl pyridines, poly anilines [12, 13, and 14]. water soluble polymers as promising corrosion inhibitors are low cost and essentially stable for metallic materials in acidic environment [15, 16, and 17]. most organic inhibitors act by adsorption on the metal surface [18]. the inhibitive power of these polymers is related structurally to the cyclic rings and heteroatoms (oxygen and nitrogen) that are the active centers of adsorption. the polymers form complexes with metal ions on the metal surface which occupy a large surface area and protect the metal from corrosive attack by agents present in the solution [17]. attempts were made to study polyvinyl alcohol (pva) as corrosion inhibitor for carbon steel in acidic media. [19, 20]. the present study is aimed at investigating inhibitive and adsorption properties of a water soluble polymer (pva) for the corrosion of mild steel in 0.2n h2so4. an aim also was to find the effects of inhibitor concentration and temperature on the inhibition efficiency. the concentration range of polyvinyl alcohol was 0.15 – 2.0 g/l, while the temperature range was 3060 o c. experimental work 1materials and equipment throughout this study carbon steel with the following composition was employed in all tests. the analysis of the carbon steel specimens in wt. % was mn 1.4, p 0.045, c 0.15, s 0.04 and the rest is fe analyzed at the state company of geological survey and mining. rectangular shaped coupons with dimensions 1cmx3cmx0.1cm were used in the weight loss experiments. thermodynamically controlled water baths was used to maintain the metal coupons in experimental designed temperatures. the temperature variations was no more than ± one degree celsius all the time and this was done by carefully monitoring the temperature in corrosion cells through thermometers immersed in the corrosive media. analar sulfuric acid was used in preparing solutions to simulate the corrosive media. double distilled water was used in all acid dilution preparation steps to ensure the desired solution concentrations. the desired majid i. abdulwahab, ayad b. ahmed and aprael s. yaro -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 23 acidinhibitor concentration was obtained for each run. water soluble polymer polyvinyl alcohol (pva) was used as inhibitor in this study. different grades are available in practical use depending mostly on the polymer molecular weight. the molecular mass and of pva used in the present investigation is 15000 g/mole and the molecular formula is shown in fig. 1: fig. 1, chemical formula of polyvinyl alcohol 2specimen preparation the rectangular test specimens with dimensions (1x3x0.1) cm were cut and a hole for suspension of 0.1 cm in diameter were made in the upper suspension area so that it can be hanged by an inert teflon thread used to hold the coupons in position during experiments. thermal stresses are released by annealing the coupons in a vacuum furnace at 600 for 1 hour; the coupons were left in furnace to cool gradually to room temperature. the coupons then are kept in a desiccator over silica gel bed until future use. prior to weight loss experiments each coupon was abraded under running tap water using silicon carbide emery papers of different grades beginning with number 200,300,400 and 600 then washed by distilled water ,dried with clean tissue, then immersed in absolute ethanol, dried, immersed in annular acetone then dried again. the cleaned coupons were then kept in a desiccator over silica gel bed ready for use. 3experimental procedure experiments were conducted under total immersion conditions of the pre cleaned carbon steel coupons in aerated and unstirred 400 ml of the respective inhibitor/blank solutions maintained at the desired temperatures of 30 o c, 40 o c, 50 o c, and 60 o c in a thermostatic water bath (± 1 °c). the immersion period was 3 hours for each experiment at the desired temperature, acid concentration and inhibitor concentration. at the end of the exposure time the metal coupons were withdrawn, cleaned, washed with running tap water followed by distilled water, then dried with clean tissue, followed by immersion in absolute ethanol, dried, immersed in analar acetone, dried then saved in a moisture free desiccator ready to be weighed. the dimensions of each coupon were measured with a vernier to the second decimal of millimeter and the analytical balance weigh accuracy was to the 0.0001 gram. 4polarization experiments the potentiostat type used in this study was weking m-lab 200 supplied from the bank electronic company originated in germany. this potentiostat has two data channels and two corrosion cells could be connected at the same time. a one liter spherical shaped glass vessel, with five necks to insert three electrodes, a thermometer, and a gas inlet opening. the vessel has a heat exchanging jacket with openings for inlet and outlet heat regulating water imported from a nearby thermostatic water thermostatic bath. figure 2 shows a schematic diagram for the electrodes arrangement in the corrosion cell. corrosion inhibition of low carbon steel in sulfuric acid using polyvinyl alcohol 24 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net fig. 2, schematic diagram of the corrosion cell the cell holds three electrodes; the working electrode was mild steel cut in circular shape, 1cm 2 surface area fitted in the electrode holder. the reference electrode (saturated calomel electrode) was used throughout this work which is calibrated with standard calomel electrode. this electrode consists from a paste of mercury and mercury chloride (hg2cl2) which are in contact and equilibrium with chloride ions in potassium chloride solution (kcl). the reference electrode was hosted in the luggin capillary which is made of glass or plastic and is generally filled with the test solution. the third electrode was the counter electrode or auxiliary electrode. this was made from platinum metal and it is fixed in the electrode holder in a similar way to working electrode. it was saved in de-ionized water to be ready for use. the auxiliary electrode is distinct from the reference electrode, which establishes the electrical potential against which other potentials may be measured, and the working electrode, at which the cell reaction takes place. the corrosion cell heat jacket is connected to efficient water thermostatic bath equipped with circulating water pump (fig. 3). the observed efficiency of temperature control was . fig. 3, picture of the thermostatic water circulating bath the potentiostat was interfaced with a pc for intercepting results obtained. the pc has a software named m-lab installed in advance .the potentiostat input and output menus is digitized by the pc and readings were available to be read on a monitor. both potentiostat modes, i.e. the open circle mode, and the polarization mode, were controlled by commands designed through the software. steady state duration times, operation modes, scan rates, types and potential sweep magnitude in addition to many functions and commands were controlled through software commands and adjustments. figure 4 shows a picture of tafel plot of the m-lab software. fig. 4, picture of tafel plot of the mlab software http://en.wikipedia.org/wiki/reference_electrode http://en.wikipedia.org/wiki/working_electrode majid i. abdulwahab, ayad b. ahmed and aprael s. yaro -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 25 5polarization procedure polarization methods involve changing the potential of the working electrode and monitoring the current which is produced as a function of time or potential. polarization mode is used to perturb the equilibrium corrosion process. the response is used to develop a model of the sample's corrosion behaviour. the potentiostat has two tasks: to measure the potential difference between working electrode and reference electrode without polarizing the reference electrode, and to compare the potential difference to a preset voltage and force a current through the counter electrode towards the working electrode in order to counter act the difference between preset voltage and existing working electrode potential. prior to each test the working electrode was cleaned and abraded with emery paper in the recommended sequence and the reference electrode, counter electrode held in position in the cell with taking care that the capillary login tip is located near the working electrode. figure 5 shows a picture of combined of the experimental arrangement including corrosion cell, potentiostat, circulating thermostatic water bath, and pc assembly. fig. 5 combined corrosion tests assembly before starting the polarization, the rest potential (ocp) should be allowed to achieve a stable value. then the working electrode is polarized 200 mv from the rest potential in the anodic and cathodic directions. tafel plots were established and corrosion currents were calculated. results and discussion 1weight loss data the corrosion rates of carbon steel in 0.2 n h2so4 solutions as function of temperature in absence and presence of different concentrations of polyvinyl alcohol (pva) are summarized in table 1 the following two equations were used to calculate weight loss corrosion rate and inhibition efficiency respectively. cr (gmd) = weight loss (g)/area (m 2 ) × time (day) … (1) ie% = (crun.-crin.) / crun. … (2) where; crun. and crin represents the corrosion rates (gmd) in absence and presence of inhibitor, respectively. in table 1, the values of the corrosion rate are calculated as grams per square meter per day which is denoted (gmd) here after. corrosion inhibition of low carbon steel in sulfuric acid using polyvinyl alcohol 26 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net table 1, corrosion rate data (gm -2 d -1 ) as a function of temperature and inhibitor concentrations for carbon steel ie % corrosion rate (gmd) c(g/l) 60 50 40 30 60 50 40 30 temp. 392.7 242.2 135.2 97.6 0 40.7 52.9 55.6 63.8 232.8 114.0 59.97 35.2 0.15 42.5 56.3 58.3 68.7 225.7 105.8 56.45 30.5 0.5 45.5 58.7 60.9 71.1 214.0 99.96 52.92 28.2 1.0 48.8 61.2 66.9 73.5 201.0 94.08 44.69 25.8 1.5 57.2 67.4 69.6 77.1 168.1 87.79 41.16 22.3 2.0 2corrosion rate evaluation a. uninhibited acid it was found that the corrosion rate of carbon steel in 0.2n h2so4 acid increased from 97.6 g/m 2 .day to 392.78(gmd) as the temperature increased from 30 to 60 ºc. figure 6 shows the variation in corrosion rate with temperature. fig. 6, variation of corrosion rate of carbon steel in uninhibited 0.2 n h2so4 at different temperatures at exposure time 3h it is obvious that the corrosion rate is highly dependent on the temperature of the uninhibited acid; this dependence is more sharp at higher temperatures, it was found that the corrosion rate nearly increased four folds in the temperature range 30-60 ºc with big jumps happening in the temperature range 40-60 ºc while less effect was noticed at lower temperatures, i.e. from 30-40 ºc. this behavior might be attributed primary to higher acid dissociation and hence more hydrogen ions available for the cathodic reaction to proceed. b. inhibited acid generally the addition of (pva) reduces the corrosion rate; the reduction depends on the amount of inhibitor added. table 1 and fig. 7 show the variation of corrosion rate with (pva) concentration at various temperature levels fig. 7, effect of pva concentration on the corrosion rate of carbon steel exposed to 0.2 n h2so4 at different temperatures, immersion period 3 hr. majid i. abdulwahab, ayad b. ahmed and aprael s. yaro -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 27 as the concentration of pva increases from 0.15 to 2.0 g/l, the corrosion rate decreases from 35.28 to 22.34 gmd at 30ºc, from 59.97 to 41.16 gmd at 40ºc, from 114.07 to 78.79 gmd at 50ºc, and from 232.84 to 168.17gmd at 60ºc, as shown in fig. 8. it is clear that the inhibitor efficiency decreases with increasing the temperature. the maximum value of inhibitor efficiency was 77.1% at 2 g/l pva concentration and 30 ºc. fig. 8, variation of pva inhibiting efficiency with pva concentration for low carbon steel in 0.2n h2so4 at various temperatures, immersion time 3 hr. 3effect of temperature as observed from table 1 and the preceding discussions the corrosion rate increases with increasing temperature for all concentrations of inhibitors used. to get more information on the role of temperature on the inhibitor performance some thermodynamic properties were calculated. applying arrhenius equations to the experimental data in table 1, plotting the logarithm of corrosion rates versus the reciprocal of absolute temperatures should give straight lines with slopes equal to – 2.303 e/r. from best line fitting to the experimental points the activation energy for corrosion at each temperature was calculated. figure 9 shows arrhenius plots used to calculate the activation energy for pva inhibitor. the results of this plot are listed in table 2. table 2, activation energies for the corrosion reaction of carbon steel in presence and absence of pva for temperature range 30-60°c activation energy (kj/mol) pva inhibitor concentration(g/l) 39.88 0.00 52.82 0.15 55.58 0.50 54.45 1.00 57.73 1.50 56.22 2.00 fig. 9, arrhenius plots for log corrosion rates versus reciprocals of temperature in presence and absence of different concentrations of pva corrosion inhibition of low carbon steel in sulfuric acid using polyvinyl alcohol 28 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net fig. 10, transition state plot for carbon steel in 0.2 n h2so4 in absence and presence of different concentrations of pva 4thermodynamic parameters of the corrosion process experimental corrosion rates from weight loss technique for carbon steel in 0.2 n h2so4 in absence and presence of pva was used to determine the enthalpy of activation and (δh*) and apparent energy of activation (δs*) for the formation of the activation complex in the transition state equation. an alternative formula for the arrhenius equation is the transition state equation [21]. cr = (rt/n.h) exp (δs*/r).exp (δh*/rt) … (3) where: h is the planck's constant, n is the avogadro's number, δs* the apparent entropy of activation and δh* the enthalpy of activation. a plot of log cr/t versus 1/t is shown in fig.10. straight lines are obtained with slopes -2.303(δh*/r) and intercepts of {log(r/nh) + 2.303(δs*/r)}, from which δh* and δs* were calculated and listed in table 3. table 3 activation parameters of pva in 0.2 n h2so4 δg* (kj/mol) δs* (j/mol.k) δh* (kj/mol) inh. conc. (g/l) pva 333 323 313 303 t, k 65.45 64.93 63.75 62.91 -84.78 37.22 blank acid 66.95 66.45 65.95 65.44 -50.38 50.18 0.15 67.04 66.61 66.19 65.76 -42.58 52.86 0.50 67.18 66.77 66.37 65.96 -40.63 53.65 1.0 67.38 67.01 66.64 66.27 -36.93 55.08 1.5 67.84 67.42 66.99 66.56 -42.93 53.55 2.0 the positive sign of ∆h * indicates that the adsorption of the inhibitor molecules is an endothermic process. in exothermic process, physic-sorption is distinguished from chemi-sorption by considering the absolute value of ∆h * . for physic-sorption process, the enthalpy of adsorption is lower than 40 kj / mol while that for chemisorption approaches 100 kj/ mol [22]. 5adsorption isotherms adsorption isotherms: inspection of table 1 suggests that pva is a moderate corrosion inhibitor for carbon steel corrosion in h2so4 media. the adsorption of the inhibitor is an essential step of the inhibition mechanism and it can provide information about the nature of metalinhibitor interaction. majid i. abdulwahab, ayad b. ahmed and aprael s. yaro -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 29 the surface coverage (θ) is an important parameter in discussing the adsorption characteristics and it is calculated by, θ = [cr (blank acid) – cr (inhibited acid)]/cr (blank acid) … (4) where: cr denotes to the corrosion rates as calculated in table 1 by using surface coverage θ values at different inhibitor concentrations, several adsorption isotherms like langmuir, temkin and freundlich etc., were assessed. langmuir equation can be written as rt q clogaloglog    1 … (5) the plot of log θ/(1θ) vs. log c according to langmuir gave straight lines with slope values close to unity suggesting that the adsorption of pva on mild steel correlates well with langmuir isotherm, fig. 11. fig. 11, adsorption isotherms for pva on carbon steel according to langmuir isotherm at various temperatures 6linear polarization results the inhibition power of a water soluble polymer (pva) was examined in the corrosion cell employing tafel extrapolation as a corrosion current measuring criteria. corrosion rates were estimated from corrosion currents and converted to weight loss in (gmd) and penetration depth in (mm/y). tables 4 through 7 lists the results of runs carried out in the corrosion cell in three inhibitor concentrations ranging from 150 ppm , 1000 ppm, 2000 ppm and in the temperature range 30-60ᵒc. table 4, polarization results for carbon steel in blank acid (0.2n h2so4) pen. loss (mm/y) wt. loss (gmd) ba bc icorr. (µa/cm 2 ) ecorr (mv) t ºc 4.7 101.0 67.0 -173.5 404.54 -434.4 30 6.67 144.0 92.2 -186.5 575.08 -435.0 |40 9.39 202.0 97.2 -215.9 809.18 -436.0 50 10.38 297.0 129.5 -239.4 1190 -441.0 60 table 5 polarization results for carbon steel in 150 ppm pva pen. loss (mm/y) wt. loss (gmd) ba bc icorr. (µa/cm 2 ) ecorr (mv) tºc 3.11 55.0 37.0 -110.5 220.26 -437.0 30 3.8 81.8 87.6 -160.5 327.1 -438.8 40 5.81 125.0 84.6 -133.6 500.2 -443.8 50 9.4 224.0 148 -134.5 897.5 -452.2 60 corrosion inhibition of low carbon steel in sulfuric acid using polyvinyl alcohol 30 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net table 6 polarization results for carbon steel in 1000 ppm pva pen. loss (mm/y) wt. loss (gmd) ba bc icorr. (µa/cm 2 ) ecorr (mv) tºc 1.98 42.7 51.4 -132.9 170.83 -438.0 30 3.04 65.4 52.1 -138.2 261.74 -440.0 |40 4.58 98.5 60.8 -133.6 394.2 -440.0 50 8.51 183.0 97.5 -116.6 733.2 -455.0 60 table 7 polarization results for carbon steel in 2000 ppm pva pen. loss (mm/y) wt. loss (gmd) ba bc icorr. (µa/cm 2 ) ecorr (mv) tºc 1.52 32.7 53.9 -116.0 130.81 -445.0 30 2.77 59.7 62.8 -128.9 238.8 -451.3 |40 4.43 95.4 77.4 -124.5 381.0 -452.0 50 6.97 150.0 76.0 -118.0 600.87 -450.0 60 figures 11 through 14 show plots of the polarization data obtained from the corrosion cell using the potentiostat. these plots represent scattered data type drawings of the logarithm of current density in (µa/cm 2 ) against the working electrode potential in mv. a. blank acid figure 11 represents data obtained for the working electrode polarization in a solution of 0.2n h2so4 in the absence of any added inhibitor (blank acid). four curves were observed each one represent polarization at certain temperature. the temperature range considered was 30, 40, 50 and 60˚c. fig. 11, experimental polarization curves for carbon steel in blank 0.2n h2so4 at various temperatures in absence of any additive. figure 11, together with table 8, show that the polarization of the mild steel coupon in the acid under consideration is influenced by the temperature variation of the corrosive media. in the temperature range 30-40 ˚c the influence on the corrosion potential was only moderate although the corrosion current calculated was influenced more pronouncedly, which may be attributed the adsorption behavior at the adsorption film. as the temperature was raised from 50˚c to 6o˚c the corrosion potential showed a pronounced jump, it is largely known that high temperatures promote metals polarization and the corrosion current obtained was clearly much higher at 60˚c. comparison of these results with the results obtained in the weight loss technique indicates that they are in the same trend. b. effects of 150 ppm pva polymer figure 12, along with table 5 gives the results of polarization of carbon steel coupon in 0.2n h2so4 in which 150 ppm of the polymer poly vinyl alcohol (pva) was dissolved. experiments were carried out in the temperature range 30-60˚c. majid i. abdulwahab, ayad b. ahmed and aprael s. yaro -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 31 fig. 12, polarization curves for carbon steel in 0.2n h2so4 in presence of 150 ppm of pva at various temperatures. the inhibition power of the polymer (pva) could be deduced from tables 4 and 5, at 40˚c the corrosion rate dropped from 144 gmd for the blank acid to 81.8 gmd for the 150 ppm pva inhibited acid giving an inhibition efficiency of about 43.2%. c. effects of 1000 ppm pva polymer figure 13 shows results of a series of experiments carried out in electrochemical corrosion cell for carbon steel corrosion in 0.2n h2so4 in the presence of 1000 ppm of the water soluble polymer (pva) dissolved in temperature range (3060˚c). table 6 and fig. 13 shows the effect of inhibitor concentration on the corrosion current and corrosion rate. the increase in pva concentration from 150 ppm to 1000 ppm caused the corrosion current to decrease in all temperature range studied. fig. 13, polarization curves for carbon steel in 0.2n h2so4 in presence of 1000 ppm of pva at various temperatures. the corrosion rate at 40˚c dropped from 81.8 gmd for 150 ppm pva to 58.3 gmd in the case of 1000 ppm pva added (a 22.7 % increase in inhibition power). same result was observed at other temperatures but in different proportions which demonstrate that increasing the polymer concentration in this range increases the inhibition power of the polymer in the acid for mild steel corrosion inhibition. the effect of temperature is also shown. increasing the temperature led to a decrease in the inhibition power of the polymer. an increase in temperature from 30˚c to 60˚c led to corrosion rate increase from 55.2 gmd and 183.0 gmd with corresponding corrosion current increase. d. effects of 2000 ppm of pva polymer figure 14 represent a series of curves obtained for the polarization results of the mild steel in acid environment consisting from 0.2n h2so4 with 2000 ppm of the water soluble polymer (pva) dissolved in at a temperature ranging from 3060˚c. corrosion inhibition of low carbon steel in sulfuric acid using polyvinyl alcohol 32 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net fig. 14, polarization curves for carbon steel in 0.2n h2so4 in presence of 2000 ppm of pva at various temperatures. examining table 7 and fig. 14 again shows the improved inhibition power gained by increasing the inhibitor concentration. the corrosion rate decreased in all temperature range studied, with increasing the polymer concentration, for instance, at 40˚, the corrosion current dropped from 327.11 to 289.70 and 238.81 µa using 150 ppm, 1000 ppm, and 2000 ppm of pva respectively. the same observation is true for the other series of tests conducted in this study. the effect of corrosive media temperature variation in this series was similar to the proceeding series. temperature increase increased the corrosion rate significantly, the corrosion current calculated increased from 150 µa to 530.6 µa as the temperature increased from 30 to 60˚c at the same pva concentration of 2000 ppm. table 8 shows the corrosion rates in gmd and inhibition efficiencies as calculated from polarization data. table 8 (a) corrosion rates and (b) corrosion efficiencies (a) inhibitor conc. ppm corrosion rate (gmd) 30˚c 40˚c 50˚c 60˚c nil nil 101 144 202 297 pva 150 55.0 81.8 125 224 1000 42.7 65.4 98.5 183 2000 32.7 59.7 95.4 150 (b) inhibitor conc. ppm inhibition efficiency (ie %) 30˚c 40˚c 50˚c 60˚c nil nil 0 0 0 0 pva 150 45.5 43.1 38.1 24.5 1000 57.7 54.5 51.2 38.4 2000 67.6 58.5 52.8 49.5 7discussion of the polarization data a. effect of pva concentration on polarization curves polarization measurements were carried out in order to gain knowledge concerning the kinetics of the cathodic and anodic reactions. figure 15 shows the effect of addition of pva on the cathodic and anodic polarization curves of mild steel in 0.2n h2so4 at 60˚c. both the cathodic and anodic reactions were affected with the addition of the polymer pva, which suggests that pva reduced anodic metal dissolution and also retarded the hydrogen evolution reaction electrochemical corrosion kinetics parameters, such as corrosion current density, tafel slopes obtained from the extrapolation of the polarization curves for fig. 15 were given in tables 4, 5, 6, and 7, respectively. it followed that the values of bc is changed with increasing inhibitor concentration, indicating the influence of the polymer compounds on the kinetics of hydrogen evolution. the pva molecule is believed to be majid i. abdulwahab, ayad b. ahmed and aprael s. yaro -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 33 adsorbed at the active metal sites of the mild steel which are amenable for corrosion reaction and block these sites most probably by its negatively charged hetroatoms thus blocking these anodic and cathodic corrosion reactions, similar results were found by oz can et al. [23, 24]. being adsorbed on the metal surface pva controlled the anodic and cathodic reactions occurring in the corrosion reaction, and then its inhibition efficiency is directly proportional to its amount adsorbed with increasing concentration. as it was seen the above tables the corrosion current is reduced corrosion potential shifting not exceeding 85mv which suggests that pva is a mixed type inhibitor in agreement with other findings in previous studies [25, 26]. fig. 15, polarization curves for carbon steel in 0.2n h2so4 in absence and presence of different concentrations of pva at 60˚c. similar conclusions could be withdrawn from the polarization kinetic data at the other temperatures, i.e., 30, 40, and 50˚c. the kinetic parameters obtained from polarization, such as corrosion current, tafel slopes were showing to follow the same trend with respect to the concentration of the pva inhibitor. b. inhibition efficiency discussions tables 8 tabulate the results obtained from polarization runs analysis. corrosion currents calculated from tafel slopes interceptions in the vicinity of the corrosion potentials was calculated and converted to the corresponding weight losses which was used to estimate the corrosion rates in presence and absence of inhibitors. figure 16 represents these data graphically. the corrosion retarding effect of pva is obvious. corrosion rates are increasing with temperature and decreasing with increasing pva concentration. this is in agreement with former results recorded in weight loss method. fig. 16, effect of inhibitor concentration on corrosion rate of carbon steel in 0.2n h2so4 in presence and absence of inhibitor (pva) to further understand the corrosion behavior of mild steel in such circumstances the effect of temperature and inhibitor concentration and type on the penetration depth for carbon steel in 0.2n h2so4 in presence and absence of inhibitor is represented in bar corrosion inhibition of low carbon steel in sulfuric acid using polyvinyl alcohol 34 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net diagrams, fig. 17 utilizing data from table 8. fig. 17 effect of inhibitor concentration and temperature on penetration depth for carbon steel inhibited by pva only conclusions the findings of this research suggest the following conclusions: 1 the corrosion rate of mild steel in 0.2 n h2so4 solution is highly temperature dependent especially at higher temperatures. 2 polyvinyl alcohol is one of those polymers which are water soluble and eco -friendly, however its inhibition power in acidic media is only moderate especially at higher temperatures and low pva concentrations. 3 corrosion inhibition power of pva increases with increasing pva concentration in the acid solution and reaches a maximum at about 2000 ppm at all temperatures investigated. 4 corrosion inhibition power of pva decreases with increasing temperature showing maximum dissolution rates at 60ᵒc. 5 kinetic study shows that the temperature dependence of the corrosion rate correlates well with the arrhenius equation in presence and absence of all inhibitor modes investigated. 6 thermodynamic parameters showed that following the addition of inhibitor the activation energy values are larger confirming that these inhibitor combinations retards the corrosion of mild steel in h2so4 by adding an extra energy barrier to the corrosion reaction. 7 linear polarization method findings show that the corrosion reaction in the acid media is activation controlled and oxygen diffusion plays only a minor role. 8 tafel extrapolation method to estimate corrosion currents and corrosion rates shows results with similar trends with corrosion rates calculated by the weight loss techniques. 9 the overall corrosion process is a function of the metal, corrodent, inhibitor structure, temperature as well as concentration. references 1 ramesh, bs. rajeswari, s., maruthamuthu, s., (2003), “effect of inhibitors and biocide on corrosion control of mild steel in natural aqueous environment”, materials letters, 57, 4547. 2 abdallah, m., (2004), “guar gum as corrosion inhibitor for carbon steel in sulfuric acid solutions”, portug. electrochica acta, 22, 16. 3 yaldirim, a., cetin, a.m., (2008), “synthesis and evaluation of new long alkyl side chain acetamide, isoxazolidine and isoxazoline derivatives as corrosion inhibitors”, corrosion sci., 50, 155-165. 4 anees a. khadom, aprael, s. yaro, abdul amir h. kadum, (2010), “corrosion inhibition by naphthylamine and phenylenediamine for the corrosion of copper–nickel alloy in hydrochloric acid”, j. of tiwan majid i. abdulwahab, ayad b. ahmed and aprael s. yaro -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 35 institute of chem. engineers, 41, 122-125. 5 sanyal b., (1981), “organic compounds as corrosion inhibitors in different environments-a review”, prog. org. coating, 9, 165-236. 6 abd-el-maksoud s. a., (2008), ” effect of organic compounds on the electrochemical behavior of steel in acidic mediaa review”. int. j. electrochem. sci. 3, 528. 7 ayman m. a., gamal a. e., husein s. i., hamad a. a., (2012), “effects of water soluble rosin on the corrosion inhibition of carbon steel‟, int. j. electrochem. sci., 7, 11834 – 11846. 8 grchev, t., cvetkovska, m. and schutze, j. w. (1991), “the electrochemical testing of polyacrylic acid and its derivatives as inhibitors of corrosion”, corr. sci., 32,103-9. 9 karthikaiselvi r., subhashini s., rajalakshmi r., (2012), “poly (vinyl alcohol – aniline) water soluble composite as corrosion inhibitor for mild steel in 1 m hcl”, arabian journal of chemistry, 5, 4, 517–522. 10schweinsberg, d. p., hope, g. a., trueman, a., otienoalego, v., (1996), “an electrochemical and sers study of the action of polyvinylpyrrolidone and polyethylenimine as inhibitor for copper in aerated h2so4”, corr. sci., 38, 587-99. 11rajendran, s., apparao, b. v., palaniswamy, n., (1998), “synergistic effect of ethyl phosphate and zn2+ in low chloride media”, anti-corr. methods and mater. 45, 5, 338-43. 12kralijie, m., mandie, z. and duie, l. j., (2003), “inhibition of steel corrosion by polyaniline coating”, corr. sci., 45, 181-98. 13desai, m. n., talati, j. d., shah, n. k., (2003), “orthosubstituted aniline-n-salicylidenes as corrosion inhibitors for zinc in h2so4”, indian j. of chem., 42a, 12, 101-6. 14shoeib, m. a., mokhtar, s. m. and abd el-ghaffar, m. a., (1998), “mechanical and corrosion protection properties of electroless nickel-polymer composite coatings”, j. metal finishing, 96, 11, 58-9. 15david ebuka arthur, achika jonathan, paul ocheje ameh and crystal anya, (2013), “a review on the assessment of polymeric materials used as corrosion inhibitor of metals and alloys”, international journal of industrial chemistry, 4, 2, 2-9. 16grchev, t., cverkovska, m. and schutze, j.w., (1991), “the electrochemical testing of polyacrylic acid and its derivatives as inhibitors of corrosion”, corr.sci, 32,103-112. 17rajendran, s., sridevi, s., anthony, n., john amalraj. a., (2005), “corrosion behaviour of carbon steel in polyvinyl alcohol”, anti-corr. methods and mater. 52, 2,102-107. 18bentiss, f., traisnel, m., lagrenee, m., (2000), “the inhibition action of 3, 6-bis(2-methoxyphenyl)-1, 2dihydro-1, 2, 4, 5-tetrazine on the corrosion of mild steel in acidic media”, corr. sci., 42,127-146. 19umoren, s.a., and solomon m.m., (2014), “recent developments on the use of polymers as corrosion inhibitors a review, the open materials science journal, 8, 39-54. 20srimathi, m., rajalakshmi, r., subhashini, s., (2014), “polyvinyl alcohol–sulphanilic acid water soluble composite as corrosion inhibitor for mild steel in corrosion inhibition of low carbon steel in sulfuric acid using polyvinyl alcohol 36 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net hydrochloric acid medium”, arabian j. of chem., 7, 5, 647-656. 21bank electronic intelegent controls-gmbh „an introduction to the principle of potentiostatic control, including basic potentiostatic circuits‟, freiberger strasse 1, d-38678-zeller feld. 22zarrok, h., zarrouk, a., salghi, r., assouag, m., hammouti, b., oudda, h., boukhris, s., al deyab, s. s., warad, i., (2013), “inhibitive properties and thermodynamic characterization of quinoxaline derivative on carbon steel corrosion in acidic medium”, der pharmacia lettre, 5 (2)), 43-53. 23badiea, a. m., mohana, k. n., (2009), "effect of temperature and fluid velocity on corrosion mechanism of low carbon steel in presence of 2 – hydrazine–4,7– dimethyl benzothiazole in industrial water", corrosion science 51, 2231 – 2241. 24ozcan, m., dehri, i., erbil, m., (2004), “organic sulphur containing compounds as corrosion inhibitors for mild steel in acidic media: correlation between inhibition efficiency and chemical structure”, appl. surf. sci., 236,155-164. 25fouda, a., moussa, m., taha, f. i., elneanaa, a. i., (1986), “the role of some thiosemicarbazide derivatives in the corrosion inhibition of aluminum in hydrochloric acid”, corr. sci., 26, 719-726. 26mccafferty, e., hackerman, n., (1972), “double layer capacitance of iron and corrosion inhibition with polymethylene diamines,” j. electrochem. soc. 119, 146-154. available online at https://ijcpe.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.19 no.2 (june 2018) 1 –7 issn: 1997-4884 corresponding authors: sameera m. hamdulla, email: na, aboosh h. hassan, email: na, yahya jarjees tawfiq, email: yahyapetroleum@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial-noderivatives 4.0 international license building geological model for tertiary reservoir of exploration ismail oil field, north iraq sameera m. hamdulla a , aboosh h. hassan b and yahya jarjees tawfiq c a university of baghdad/college of engineering/ petroleum department b north oil company/kirkuk c university of kirkuk/college of engineering/ petroleum department abstract geologic modeling is the art of constructing a structural and stratigraphic model of a reservoir from analyses and interpretations of seismic data, log data, core data, etc. ‎[1]. a static reservoir model typically involves four main stages, these stages are structural modeling, stratigraphic modeling, lithological modeling and petrophysical modeling ‎[2]. ismail field is exploration structure, located in the north iraq, about 55 km north-west of kirkuk city, to the north-west of the bai hassan field, the distance between the bai hassan field and ismael field is about one kilometer ‎[3]. tertiary period reservoir sequences (main limestone), which comprise many economically important units particularly reservoir pay zone, in ismail field are belong to middle miocene age and oligocene age, which includes six formations, jeribe, bajwan, baba, baba/palani and palani formation. the information of ismail field such as final well report, drill stem test, completion test and well logs data also previous studies and results of core data, indicated that hydrocarbons are accumulated in the baba formation. the main purpose of this study is to make use of all the available sets of data acquired from ismail field to build a static geological model for baba formation in ismail field to get full description for this reservoir. keywords: geologic modeling, ismail field accepted on 12/3/2018 1introduction the most important phase of a reservoir study is probably the definition of a static model of the reservoir rock, given both the large number of activities involved, and its impact on the end results. as we know, the production capacity of a reservoir depends on its geometrical/structural and petrophysical characteristics. the availability of a representative static model is therefore an essential condition for the subsequent dynamic modeling phase. a static reservoir study typically involves four main stages, carried out by experts in the various disciplines, these stages are structural modeling, stratigraphic modeling, lithological modeling and petrophysical modeling ‎[2]. 2model design petrel 2009 software was chosen to build geological model for exploration ismail field. petrel is a software application package for subsurface interpretation and modeling, allowing building and updating reliable subsurface models. it is a latest reservoirs modeling software recently deployed by schlumberger information solutions inc. for the purpose of this study, a data base was created within petrel, clearly delineating the different information and data needed to complete the study. the geological, and petrophysical data were imported to petrel within the main data base. this made it possible to generate and visualize the imported data in 2d as well as 3d. the work flow design used for the study and wide range of functional tools in the petrel software include: 3d visualization, well correlation, 3d mapping, and 3d grid design for geology simulation, well log up scaling, petrophysical modeling, data analysis, and volume calculation. 3data preparation data preparation is the basis for geologic model. this geologic model building chiefly applies software of petrel. on the basis of software demand and research area characteristic, the data prepare for this 3d-geological model are well heads, well tops, well logs (raw data and cpi), and core analysis. s. m. hamdulla, et al./ iraqi journal of chemical and petroleum engineering11,1 (2018) 1-7 2 4import data import data describes the data import procedure, various data formats supported and organize the imported wells in sub folders. well data are imported in three steps: 4.1. well head a well head include the top position of the well path, the measured depth along the path, the well name and optionally a well symbol. 4.2. well tops well tops are used to marker representing significant points along the well path when there is a change in stratigraphy between reservoir units of well is-1. 4.3. well logs data well logs included; gamma ray, neutron, sonic, density and resistivity as well as the cpi (porosity, and water saturation). well logs imported log values along the well path and attached to the path. 5structural modeling structural modeling was used for building geological model. it was subdivided into three processes as follows: fault modeling, pillar gridding, and vertical layering. all the three operations were performed one after the other to form one single data model ‎[4]. structural maps were built depending on the depth structural map for top of jerebi formation. fig. 1 show structural contour maps for top of baba formation in exploration ismail field. 6stratigraphic modeling in this study, the stratigraphy description will be focused on the tertiary period reservoir sequences (main limestone), which comprise many economically important units particularly reservoir pay zone (oligocene and miocene) ages. it is worth mentioning that the division of formations in ismail field is similar to the division in the bai hassan field completely. tertiary period formation in this field consists of a series of sedimentology that had been deposited in the period between the end of upper cretaceous (end of shiranish formation) and early middle miocene. the main divisions were adopted as contained in the study of stratification and porosity units study of the tertiary rock in bai hassan field, issued by the north oil company, department of fields/department of geology, 1980 ‎[5]. fig. 1. 3d structural depth map for top of baba formation in this study, we focus on the main limestone reservoir which represented by baba formation. baba formation includes the most coral reefs in the upper parts while includes the reef facies in the lower parts. most rocks of this formation consist of dolomite. the upper part of this formation contains greatly coral reefs while presence of these coral reefs in the lower part of the formation is rarely ‎[5]. based on this, baba formation can be divided into two sections: a. the upper part, which consists mostly of coral reefs. b. bottom part, which contains mainly limestone. the stratigraphy of baba formation in ismail field was prepared by using petrel (2009) software, as shown in fig. 2, by depending on the graphical well log stratigraphy and lithology description for well is-1. fig. 2 shows the stratigraphy of baba formation in well is-1. s. m. hamdulla, et al./ iraqi journal of chemical and petroleum engineering11,1 (2018) 1-7 3 7scale up well logs when modeling petrophysical properties, a 3d grid cell structure is used to represent the volume of the zone. the cell thickness will normally be larger than the sample density for well logs. as a result, the well logs must be scaled up to the resolution of the 3d grid before any modeling based on well logs can be done. this process is also called blocking of well logs ‎[4]. many statistical methods were used to scale up such as (arithmetic average, harmonic, and geometric method). the porosity and water saturation have been scaled up using above averaging methods. fig. 2. stratigraphic model of baba formation s. m. hamdulla, et al./ iraqi journal of chemical and petroleum engineering11,1 (2018) 1-7 4 8facies modeling facies modeling is a means of distributing discrete facies throughout the model grid. definition of certain number of lithological types (basic facies) for the reservoir in question, which are characterized on the basis of lithology proper, sedimentology and petrophysics ‎[2]. facies model was built depending on the graphical well log stratigraphy and lithology description for well is-1. statistical sequential gaussian simulation algorithm was used as a statistical method to build facies model. data analysis was first performed to calculate normal score transforms and experimental variogram ranges. variogram ranges were set to1000 m in the major direction, 1000 m in the minor direction, and variable values in the vertical direction, using an exponential variogram model with a variable nugget and a major direction azimuth of -45°. we observed from fig. 3 which represents the facies distribution through baba formation that: this formation represents a four-reef facies and highly dolomitized limestone, porous, vugy crystalline with streaks of anhydrite beds and marel. fig. 3. facies distribution of baba formation 9petrophysical modeling petrophysical property modeling is the process of assigning petrophysical property values (porosity and water saturation) to each cell of the 3d grid. petrophysics model was built using geostatistical methods. the geostatistical algorithm (statistical sequential gaussian simulation algorithm) represents a statistical method, which fits with the amount of available data. the petrophysics models include: 9.1. porosity model porosity model was built depending on the results of porosity logs which have been corrected and interpreted by ip software. statistical sequential gaussian simulation algorithm was used as a statistical method to build porosity model. data analysis was first performed to calculate normal score transforms and experimental variogram ranges. variogram ranges were set to 5000m in the major direction, 5000m in the minor direction, and variable values in the vertical direction, using an exponential variogram model with a variable nugget and a major direction azimuth of -45°. fig. 4 represents the porosity distribution through baba formation in well is-1. from the previous figure it is clear that baba formation is homogeneous and has a very good value of porosity. the porosity in general in this unit is good and ranged between (0.17-0.19), due to the effect of the high dolomitization. porosity increasing toward north western direction of the field which has good porosities in that sector which is greater than 19%. s. m. hamdulla, et al./ iraqi journal of chemical and petroleum engineering11,1 (2018) 1-7 5 9.2. water saturation model water saturation model was built depending on the results of logs. the same geostatistical method was used in the porosity model (statisticaln sequential gaussian simulation algorithm), according to available data that deduced from interpreted logs. data analysis was first performed to calculate normal score transforms and experimental variogram ranges. variogram ranges were set to 5000m in the major direction, 5000m in the minor direction, and variable values in the vertical direction, using an exponential variogram model with a variable nugget and a major direction azimuth of -45°. from fig. 5 which is represent the water saturation distribution through baba formation, it is clear that this formation has very low values of water saturation which are ranged from less than 5% to the less than 65%. the hydrocarbons are concentrated in the south, south eastern, north western, east and west parts in the ismail field through this formation. this formation may be considered as reservoir due to its economical hydrocarbons amounts. fig. 4. porosity distribution in baba formation fig. 5. water saturation distribution in baba formation s. m. hamdulla, et al./ iraqi journal of chemical and petroleum engineering11,1 (2018) 1-7 6 10oil water contact model oil/water contact is the depth where water saturation first reaches close to100%. this sometimes called the free water level (fwl). perforations below this point will produce 100% water. oil water contact can usually be picked on the resistivity log where resistivity reaches its lowest values in a clean, porous reservoir. sometimes it is difficult to recognize porous high water statured zone from logs data due to present of shale or in high heterogeneity carbonate rock where porosity was too low, then in this case oil water contact is located where water saturation become 100%. the contact of oil/water in the well ismail-1 is determined from resistivity log. it was fixed on depth 1496 m rtkb (1200 m msl) within baba formation, by depending on comparison between the resistivity log and dst (drill stem test) results for interval (1510-1541) which indicate productive water existence with salinity 70000 ppm and density 1.04 gm/cc. 11conclusions in this study, the following conclusions may be drawn; and a number of recommendations are suggested which could enhance our understanding and evaluation of the reservoir characteristics of baba formation in ismail oil field under study. 1the tertiary main limestone reservoir in well is-1 is baba formation (unit b), upper oligocene as interval section from (1466 m. rtkb) to the owc level. 2calculations of the porosity from porosity logs indicated that the primary porosity is the main controller porosity in the porous media, where the secondary values are very scarce and ranged between (0.2-3.4) percent. 3the clay volume calculations from gr log, pointed out the clay in well is-1 is distributed in varied ratio, where the minimum clay volume (3.3–10.3%) was recorded in the bajwan and baba formations. the clay volume was concentrated in the other formations (jeribi, baba/palani, palani) and it was relatively high (41.7 – 44.5) %. 4the oil water contact level in the ismail field within tertiary period was found to be located in 1496 m rtkb (1200 m. msl). 5the cut off results indicated that the best reservoir characteristics are associated with unit (b), while other units and formations have poor reservoir characteristics, especially with water saturation cut off value. 6the porosity and water saturation model showed that the good petrophysical properties direction to the west and north-west direction of the field. 7oil initially in place (oiip) is calculated for main limestone reservoir in ismail field and it is found equal (15.687*10 6 ) stb, where the last study about ismail field estimated ooip equal to 14.21*10 6 stb. 12recommendations 1making three-dimensional seismic survey to illustrate and clarify the structural geometry of the ismail field and determine the levels of fluid contact and field extensions, especially the field extension toward north east and reconsider the location of exploratory and evaluating wells by depending on the results of the mentioned seismic interpretations. 2using modern techniques such as (instantaneous frequency analysis) and (seismic inversion analysis) in determining the dimensions of ismail field. the use of traditional methods in determining the dimensions of stratigraphic traps do not give accurate results in calculation of oil reserves accurately. 3drill more wells in ismail structure with using advanced and modern logging tools such as ept log, nmr log, etc. to get more accurate results and new data. 4develop an integrated reservoir study for this field using the geological modeling data to establish reservoir management strategies and provide a basis for more developing plans. 5give more focus on (unit b) by making more production test and taking more core data as it has good reservoir production properties. 6make a study to build accurate geological model for cretaceous age formations in ismail field, after drilling some wells. references [1] ezekwe, nnaemeka, 2011:” petroleum reservoir engineering practice”. [2] luca cosentino, 2001: “integrated reservoir study”, institute françois petroleum publication. [3] eoc (oil exploration company), 2011: “geological and evaluative study for ismail field”, unpublished study. [4] schlumberger, 2008: “petrel online help”, petrel 2008 version 2008. [5] eoc (oil exploration company), 2005: “reevaluation study of ismail field”, unpublished study. http://cds.cern.ch/record/1512557 http://cds.cern.ch/record/1512557 https://books.google.iq/books?hl=en&lr=&id=vgwecgaaqbaj&oi=fnd&pg=pr7&dq=integrated+reservoir+study&ots=ubtapzcqhy&sig=y-ohabx4cdce24vb-itl-1dikfy&redir_esc=y#v=onepage&q=integrated%20reservoir%20study&f=false https://books.google.iq/books?hl=en&lr=&id=vgwecgaaqbaj&oi=fnd&pg=pr7&dq=integrated+reservoir+study&ots=ubtapzcqhy&sig=y-ohabx4cdce24vb-itl-1dikfy&redir_esc=y#v=onepage&q=integrated%20reservoir%20study&f=false s. m. hamdulla, et al./ iraqi journal of chemical and petroleum engineering11,1 (2018) 1-7 7 بناء موديم جيونوجي نهمكمن انثالثي في حقم اسماعيم االستكشافي، شمال انعراق انخالصة ِىدًٌ رشوٍجً وطجبلً ٌٍّىّٓ ِٓ خالي رحًٍٍ ورفسٍش اٌّعٍىِبد اٌزٌزاٌٍخ اٌّىدًٌ اٌجٍىٌىجً هى ثٕبء اٌّىدًٌ اٌجٍىٌىجً االسزبرٍىً ّٔىرجٍب ٌزضّٓ اسثعخ وِعٍىِبد جس االثبس وِعٍىِبد رحبًٌٍ اٌٍجبة.. اٌخ. حمً زٌبئً.ِشاحً، وهزٖ اٌّشاحً هً اٌّىدًٌ اٌزشوٍجً واٌّىدًٌ اٌطجبلً واٌّىدًٌ اٌسحًٕ واٌّىدًٌ اٌجزشوفٍ اٌغشثً ِٓ ِذٌٕخ وٍُ ِٓ شّبي 55اسّبعًٍ عجبسح عٓ رشوٍت اسزىشبفً، ٌمع فً شّبي اٌعشاق، حىاًٌ وشوىن، واٌى اٌشّبي اٌغشثً ِٓ حمً ثبي حسٓ، واٌّسبفخ ثٍٓ حمً اسّبعًٍ وحمً ثبي حسٓ حىاًٌ واحذ رىىٌٕبد ِهّخ الزصبدٌب خصىصب طجبلٍخ عصش اٌّىّٓ اٌثالثً )ِىّٓ اٌىٍس اٌشئٍسً(، واٌزً رشًّ وٍُ. ِٕبطك اٌعطبء اٌّىًّٕ, فً حمً اسّبعًٍ رعىد اٌى عصش االوٌٍجىسٍٓ وعصش اٌٍّىسٍٓ االوسظ ورزضّٓ اٌّعٍىِبد حىي حمً سزخ رىىٌٕبد هً جشٌجً , ثبجىاْ اٌصٍذ , ثبجىاْ اٌّسبًِ , ثبثب , ثبثب/ثبالًٔ , ثبالًٔ. اٌذساسبد اٌسبثمخ واٌفحىصبد االوّبٌٍخ وِعٍىِبد جس االثبس ووزٌهاسّبعًٍ ِثً اٌزمبسٌش إٌهبئٍخ ٌٍجئش اٌهذف اٌشئٍسً ِٓ وِعٍىِبد رحبًٌٍ اٌٍجبة، وٍهب رشٍش اٌى اْ اٌهٍذسووبسثىٔبد رجّعذ فً رىىٌٓ )ثبثب(. ٌٓ هزٖ اٌذساسخ هً اسزخذاَ وً اٌّعٍىِبد اٌّزىفشح واٌّسزحصٍخ ِٓ حمً اسّبعًٍ ٌجٕبء ِىدًٌ جٍىٌىجً ٌزىى )ثبثب( فً حمً اسّبعًٍ ٌحصىي عٍى اٌىصف اٌىبًِ ٌهزٖ اٌّىّٓ. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.22 no.3 (september 2021) 1 – 9 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: qahtan a. abdul-aziz , email: qahtan.aziz@coeng.uobaghdad.edu.iq, name: hassan a. abdul-hussein, email: hassanaltee@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. development a statistical relationship between compressional wave velocity and petrophysical properties from logs data for jeribe formation asmari reservoir in fauqi oil field qahtan a. abdul-aziz and hassan a. abdul-hussein petroleum engineering department, college of engineering, university of baghdad, baghdad, iraq abstract the compressional-wave (vp) data are useful for reservoir exploration, drilling operations, stimulation, hydraulic fracturing employment, and development plans for a specific reservoir. due to the different nature and behavior of the influencing parameters, more complex nonlinearity exists for vp modeling purposes. in this study, a statistical relationship between compressional wave velocity and petrophysical parameters was developed from wireline log data for jeribe formation in fauqi oil field south est iraq, which is studied using single and multiple linear regressions. the model concentrated on predicting compressional wave velocity from petrophysical parameters and any pair of shear waves velocity, porosity, density, and fluid saturation in carbonate rocks. a strong linear correlation between p-wave velocity and s-wave velocity and between p-wave velocity and density rock was found. the resulting linear equations can be used to estimate p-wave velocity from the s-wave velocity in the case of both. the results of multiple regression analysis indicated that the density, porosity, water-saturated, and shear wave velocity (vs) are strongly related to vp. keywords: porosity, water saturation, multiple regression, compressional wave received on 18/04/2021, accepted on 04/07/2021, published on 30/09/2021 https://doi.org/10.31699/ijcpe.2021.3.1 1introduction since carbonate rocks are essential components of the world's oil and gas reservoirs, further research into their physical characteristics is required. when combined with shear wave velocity (vs), compressional wave velocity becomes a useful parameter for seismic analysis, lithologic identification [1,2], and pore fluid and pore pressure information [3,4,5]. a logical relationship between inputs (well log data) and outputs (vp) is required for selecting input data. many factors influence compressional wave velocity; four of the most significant in carbonate rocks are neutron porosity (nphi) and bulk density (rhob), s-wave, and pour water. in addition, weathering, alteration zones, bedding planes, and joint properties (filling materials, roughness, water, dip, and strike, and so on) all affect the sound velocity [6, 7,8,9,10,11]. velocity is determined by the ratio of rock moduli to density. the elastic moduli by density term, dependent on rock properties such as fluid saturation and rock texture, produce velocity variations. the theory of elasticity in rocks demonstrates that seismic waves propagate in two mechanisms, each propagating independently [12]. the work of rock moduli over density can estimate the seismic velocities, vp and vs., of isotropic rock material. when the rock is saturated with water, compressional waves move faster than when it is dry or gas-saturated. shear waves have the opposite behavior, with shear velocities higher in dry or gas-saturated cases than in water-saturated cases [13,14]. at 10% saturation, the strongest decrease in intensity was observed. the volumetric pressure of the cracks and the sample decreased as the water saturation decreased, owing to water easing crack initiation and propagation [14]. the compressional wave (vp) can estimate the water absorption characteristic as an objective parameter. however, water absorption, which is an effective rock index, is dependent on the mineralogy and porosity of the rock [15, 16]. several researchers [18, 19, 20, 21, and 22] established empirical correlations to estimate compressional wave velocities. the amount of data collected has a big impact on empirical predictions. predictions of this kind can also be used for effective planning. table 1 shows a range of relationships for predicting compressional waves from petrophysical parameters that have been published. as a result, using petrophysical properties to predict compressional waves is more accurate, particularly in carbonates rocks. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:qahtan.aziz@coeng.uobaghdad.edu.iq mailto:hassanaltee@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2021.3.1 q. a. abdul-aziz and h. a. abdul-hussein / iraqi journal of chemical and petroleum engineering 22,3 (2021) 1 9 2 table 1. previous empirical relationships for compressional wave prediction year. relationshiof vp (km/sec) reference 1963 vp/vs=1.8 or vp=1.8vs (pickett, 1963) 1993 vp= 5.45-−6.17∅ gist et al 1993 2003 𝑉𝑝 = 2.8𝜌 − 1.5752 christensen and stanly 2012 𝑉𝑝 = 0.09𝑉𝑠 + 1.95 morteza karam et al. 2019 𝑉𝑝 = 2.7037𝜌 − 2.3668 siddharth garia 2019 𝑉𝑝 = 6.12 − 0.444𝑊𝑎 siddharth garia,et,al. however, there are some studies in existence that use multiple regressions and come up with encouraging results. this research focus is developing a single and multiple regression vp prediction in carbonates by utilization of conventional well logs. this study presents a regression analysis (statistical method) used to create a correlation to predict compressional waves and among effective petrophysical properties in dolomite formation (carbonate reservoirs) using jmp software. the development of empirical models in which the measurable well logs can estimate vp will also be outlined multiple regression for accurate prediction of vp in the investigated reservoir. 2material and methods missan oilfield is located in southeastern iraq and close to the iraq-iran border. the field consists of three producing oilfields, namely abu ghirab, buzurgan, fauqi oilfields. structurally fauqi oilfield ranges about 30km × 7 km with two domes in the north and south, respectively; nw-se long axis anticline has two sets of reservoirs, tertiary asmari and cretaceous mishrif. asmari reservoir is divided into three pay zones.a,b,and c . the pay zone, a of asmari consists of the main dolomite (jeribe formation). the interval of jeribe is from depth 2996 to 3044 m; this interval is the area of the present study. there is no depth on the compressional waves (vp), but the (vp) is affected by the petrophysical properties. the pay zone b is dolomite intercalated with sandstone, limestone, and thin shale. the pay zone c is mainly the sandstone, intercalated with a few dolomite, mudstone, and limestone. the study presents multivariate regression analysis using the jmp software to develop a new correlation to predict compressional waves and among effective petrophysical properties of a productive carbonate (dolomite) section of southeast iraq (fauqi a field – jeribe formation). the jeribe formation is considered one of the important reservoirs in the misan oilfields. it will also be discussed how to construct empirical models that use observable well logs to estimate vp. the relationship between the input data and the outcomes was verified using data analysis. logs and core plugs can also calculate sonic wave data, but logs provide more data and a better representation of a reservoir [23]. because of the complexity of the relationship between (vp) values and all rock and fluid properties, only the most essential and observable rock and fluid properties (as determined by well logging data) were chosen as the model's key input parameters. as a result, the parameters chosen should have a significant impact on vp. to determine which variables have the most significant impact on (vp), as well as to compare the relationship between compressional wave velocity and other parameters and petrophysical logs (vs., nphi, rhob, sw), it was discovered that there is a close relationship between compressional and shear wave velocity, especially in carbonate rocks. 3calculations and analysis to model the output function, a collection of observations from the reservoir, such as well logs or core measurements, can be linked to the regression analysis result. simple regression analysis or a multiple regression analysis may be used to accomplish this. the relationship between two variables is often modeled using simple regression analysis. on the other hand, multiple regression analysis uses more than one predictor variable and can be more reliable when analyzing p-wave data [ 24]. table (2) represents log data of physical rock properties and elastic waves (p and s-waves) velocity for jeribe formation. the data in table 2 is the sample data used in the program (jmp) software to obtain the relationships between (vp) and the physical properties. 3.1. single linear regression analysis it can be seen in many engineering problems that specific data varies in an ascending or descending pattern. many studies have shown, for example, that as vp rises, the number of rock samples rises as well. therefore, it is worthwhile to investigate whether there is a link between -p-wave velocity and petrophysical parameters when estimating carbonate rocks using single linear regression. a. relation between p-wave and s-wave velocity the compressional wave velocity is linearly related to the shear wave velocity as shown in fig. 2 the high regression r 2 = 0.946. the scatter of even the mean values around the regression lines is due to complex depositional environments and digenetic processes. reveals a strong correlation between the two velocities which enables estimation of one velocity having another one; the equation defines this relationship shown below: 𝑉𝑝 = 2.122𝑉𝑠 − 1.195 (1) javascript:; javascript:; q. a. abdul-aziz and h. a. abdul-hussein / iraqi journal of chemical and petroleum engineering 22,3 (2021) 1 9 3 b. relation between p-wave velocity and porosity a similar trend is presented between compressional wave velocity (vp) and porosity (ø), plotted in fig. 3 the p-wave velocity is declining as the porosity decreases. an important point can be concluded from this figure there is a scattering around the curve which can be attributed to the heterogeneity of carbonate in which the void proportions and pore size distributions within the rock fabric are complex; the relationship between p-wave and porosity gives r 2 = 0.759, and equations of the relation are; 𝑉𝑝 = 6.947 − 0.1542𝑁𝑃𝐻𝐼 (2) fig. 1. flowchart of the computer software to estimate vp fig. 2. compressional wave velocity versus shear wave fig. 3. compressional wave velocity versus nphi c. relation between the p-wave velocity and bulk density the relationships between the p-wave velocity and rock density have been extensively investigated. p-wave velocity increases linearly with a bulk density, as shown in fig. 4. the results revealed that there is scattering around the bulk density –velocity curves. this can be attributed to the heterogeneity of carbonates formation, mixed with dolomite intercalated with argillaceous dolomite. good relation between pwave velocity and bulk density with r2 =0.833 according to equation (3) of the relation is; 𝑉𝑝 = 4.284𝜌 − 6.22 (3) https://www.sciencedirect.com/science/article/pii/s2096249520300351#fig3 https://www.sciencedirect.com/science/article/pii/s2096249520300351#fig3 q. a. abdul-aziz and h. a. abdul-hussein / iraqi journal of chemical and petroleum engineering 22,3 (2021) 1 9 4 table 2. results of elastic waves (p-and s-wave velocity) with physical properties for jeribe formation depth m vp km/sec vs km/sec density gm/cc nphi٪ sw٪ 2996 5.25 3.04 2.65 0.3 56 2297 5.25 3.04 2.6 11.6 42 2998 5.89 3.34 2.76 10.6 68 2999 5.88 3.33 2.78 10.6 82 3000 5.97 3.37 2.77 9 92 3001 5.9 3.34 2.82 7.4 100 3002 6.07 3.42 2.87 4.9 100 3003 6.12 3.44 2.85 4.2 100 3004 6.01 3.39 2.85 5.1 100 3005 6.2 3.48 2.85 4.6 100 3006 6.09 3.43 2.81 5.4 100 3007 5.74 3.27 2.83 6.6 100 3008 5.74 3.34 2.74 12.7 85 3009 5.7 3.25 2.77 11.5 67 3010 5.81 3.29 2.73 12 65 3011 6.09 3.43 2.84 7.3 100 3012 5.87 3.34 2.84 9.3 94 3013 5.78 3.29 2.84 8.3 56 3014 6.17 3.47 2.83 5.7 100 3015 6.08 3.42 2.79 8.9 56 3016 6.03 3.4 2.85 4.7 100 3017 6.06 2.41 2.92 1.3 100 3018 6 3.39 2.86 4.2 100 3019 6.02 3.4 2.82 6.8 100 3020 6.02 3.4 2.83 6.3 100 3021 5.94 3.36 2.79 9.5 100 3022 6.03 3.4 2.83 6.2 100 3023 5.75 3.27 2.76 11.2 65 3024 5.15 2.99 2.64 18.1 45 3025 5.34 3.08 2.65 9.6 45 3026 4.64 2.75 1.95 12.9 19 3027 3.95 2.43 2.3 16 22 3028 5.32 3.07 2.97 5.8 64 3029 5.6 3.2 2.81 7.4 67 3030 5.64 3.22 2.73 9.6 82 3031 3.56 2.25 1.71 18.8 20 3032 4.78 2.82 2.54 12.2 32 3033 5.37 3.09 2.65 10.8 71 3034 4.15 2.52 2.37 14.3 34 3035 5.82 3.3 2.79 7.5 68 3036 5.58 3.19 2.7 12.6 74 3037 5.53 3.17 2.7 13.2 45 3038 5.58 3.19 2.86 13 54 3039 5.98 3.38 2.82 6.1 73 3040 5.77 3.28 2.77 9.3 78 3041 5.46 3.13 2.75 7.7 41 3042 5.53 3.17 2.8 4.2 43 3043 4.57 2.72 2.56 11.8 37 3044 3.52 2.23 2.38 21.1 33 d. relation between p-wave velocity and water saturation the compressional wave (vp) of rocks is influenced when exposed to fluids. the plot below showing in the relation between pwave velocity and water saturation values figure. five, the water saturation increases, and pwave velocity increase with r 2 =0.703 for dolomite. according to equation (4), p-wave velocity increase linearly with increasing water saturation. the equation of the relation is: 𝑉𝑝 = 4.063 + 0.02043 ∗ 𝑆𝑊 (4) fig. 4. compressional wave velocity versus bulk density fig. 5. compressional wave velocity versus water saturation e. comparison between new correlations with the previous empirical correlations in this section, the developed correlations have been compared with some previous correlations in table. 1. the reason is to check whether this study has improved the literature. table 1 for validation purposes as shown in fig. 6 fig. 6. comparison between equations (2, 3) and other empirical relations to predict vp. for dolomite rock formation from log data q. a. abdul-aziz and h. a. abdul-hussein / iraqi journal of chemical and petroleum engineering 22,3 (2021) 1 9 5 fig. 7. measured and predicted vp using multivariate regression. (eq. 2,3) and other empirical relations 3.2. multiple regressions instead of equations (1, 2, 3, and 4), density (rhob) and s-wave velocity vs. were used to add to the vp model to improve the accuracy of the regression (prediction). the predictive capability of multiple regressions is greatly improved when different variables are used to predict the p-wave velocity. multiple variables are used to obtain a more accurate prediction of a variable. using nphi (the calculation of neutron porosity), rhob (the bulk density), and vs. (shear wave velocity) as separate variables, this program uses multiple regression to estimate compressional wave velocity in jmp. it would help if you started by investigating the relation between compression wave velocity and the parameters you will be controlling (nphi, rhob, sw, and vs), then look for coefficients (a, b, c, d, e, and f) in the equation above to discover that: 𝑉𝑝 = 𝑎 + 𝑏 ∗ 𝑉𝑠 + 𝑐 ∗ 𝑁𝑃𝐻𝐼 + 𝑑 ∗ 𝑅𝐻𝑂𝐵 + 𝑒 ∗ 𝑆𝑊 (5) nphi is neutron porosity expressed as a fraction, rhob is bulk density in gm/cc, vp is compressional wave velocity in km/s, and vs. is shear wave velocity in km/s, and sw is a fraction. it should be pointed out that using the complete set of input data as parameters in multiple regression models also leads to the use of all of the data available wells. a new model was retimed, and the resulted equation was: 𝑉𝑝 = 0.1565 + 1.6087 ∗ 𝑉𝑠 − 0.0350 ∗ 𝑁𝑃𝐻𝐼 + 0.20409 ∗ 𝑅𝐻𝑂𝐵 + 0.0000403 ∗ 𝑆𝑊 (6) the suggested equation could be as follow: 𝑉𝑝 = 𝑎 + 𝑏 ∗ 𝑉𝑠 + 𝑐 ∗ (𝑉𝑠 + 𝑑)2 + 𝑒 ∗ 𝑁𝑃𝐻𝐼 + 𝑓(𝑁𝑃𝐻𝐼 + 𝑔)2 + ℎ ∗ 𝑅𝐻𝑂𝐵 + 𝐽 ∗ 𝑆𝑊 and the eq. 6 using the jmp software can be written as: 𝑉𝑝 = 1.362 + 1.395𝑉𝑠 − 0.647(𝑉𝑠 − 3.179)2 − 0.034 ∗ 𝑁𝑃𝐻𝐼 + 0.002(𝑁𝑃𝐻𝐼 − 9.348)2 − 0.018 ∗ 𝑅𝐻𝑂𝐵 + 0.0014 ∗ 𝑆𝑊 (7) the estimated vp using the equation (7) provides a suitable match measured vp as shown in fig. 8 with r 2 of about 0.93, while fig. 9 presents the computed vp using equation (7) and log compressional wave velocity from the real field data versus depth for well 28 in fauqi oil field. fig. 9 shows the continuous profiles of the actual and predicted compressional wave velocities, in which developed equation (7) has shown a reasonably accurate vp prediction along the whole section. multiple regressions presented a robust correlation to predict compressional wave velocity from well log data. the multiple linear regressions of the presented variables show a strong correlation among vp values predicted from well logging data. all two methods, empirical and multiple regressions were applied log data to predict compressional wave velocity for the carbonate reservoir (dolomite). the results show that the statistical method performs better than empirical models, which can be used only to obtain an order of magnitude for compressional wave velocity, as shown in fig. 8, the excellent agreement between filed data and new correlation. for more validation, we compare the new correlation with field data and other mentioned correlations as shown in fig. 10. fig. 8. plots of predicted vp using multivariate regression equation versus measured vp from the log for well fauqi-27 (equation 7) q. a. abdul-aziz and h. a. abdul-hussein / iraqi journal of chemical and petroleum engineering 22,3 (2021) 1 9 6 fig. 9. measured and predicted vp using multivariate regression equation (equation 7) fig. 10. comparison between new correlation (eq. 7) and other correlation with the actual data for fauqi-27 3.3. error analysis to further analyze the errors between calculated p-wave and actual p-wave, the following formula was adopted to calculate the absolute errors: two criteria were used to evaluate the accuracy of this correlation, eq 7 compared to three correlations. these criteria are [25]; a. the average absolute relative error, eq. 𝐴𝐴𝑅𝐸 = 1 𝑁 ∑ [| 𝑋𝑚𝑒𝑎𝑠𝑢𝑟𝑒𝑑(𝑖)−𝑋𝑐𝑎𝑙𝑐𝑢𝑙𝑎𝑡𝑒𝑑(𝑖) 𝑋𝑚𝑒𝑎𝑠𝑢𝑟𝑒𝑑(𝑖) |] 𝑁𝑖=1 ∗ 100% (8) b. the standard deviation error is given by eq. 𝑆𝐷 = √( 1 𝑁−1 ∑ [| 𝑋𝑚𝑒𝑎𝑠𝑢𝑟𝑒𝑑(𝑖)−𝑋𝑐𝑎𝑙𝑐𝑢𝑙𝑎𝑡𝑒𝑑(𝑖) 𝑋𝑚𝑒𝑎𝑒𝑜𝑟𝑒𝑑(𝑖) |] − 𝐴𝐴𝑅𝐸𝑁𝑖−1 ) 2 (9) fig. 11 shows that the new correlation provides the most accurate results than the other correlations. it gives (0.000451) standard deviation error compared with the other correlations, which give at least double standard deviation error, the new correlation also gives a lower average absolute relative error than the other correlations, as shown in fig. 12. fig. 11. sd% for the new and the other three correlations for fauqi-28 fig. 12. aare % for the new and the other three correlations for fauqi-28 4conclusions this study presents a set of relationships to estimate the p-wave velocity and petrophysical properties based on well log data using the multiple regression analysis techniques. in addition, a field case (fauqi oil field, jeribe formation), located in southeast iraq, was conducted to correlate the compressional wave velocity with petrophysical properties. q. a. abdul-aziz and h. a. abdul-hussein / iraqi journal of chemical and petroleum engineering 22,3 (2021) 1 9 7 the most significant difference between this study and previous studies is that the new model to predict (vp) depend on four-parameter (mr), including porosity, density, water saturation, and shear wave velocity but previous study, the relationship between the two variables are the essential parameters to influence p-wave prediction. the conclusion of this study can be summarized in the following points: 1it presents a more accurate correlation to estimate compressional wave velocity in jeribe formation eastern south of iraq fauqi oil field using conventional well log data. 2the analysis revealed that vp could be estimated by correlation with vs. and nphi and sw density. pwave shows a very strong correlation with this parameter, with a coefficient of 0.93 avoiding the dipole substitution; if dipole substitution is not available as the learned in the abovementioned regression, the predictors include vp, which was developed to improve the accuracy of vp prediction in the studied field. 3therefore, this model can be applied accurately, given the observed consistency between the results of the model and data. predict carbonate concentration in the reservoir 4the comparison of the results of three correlation (siddharth, gist, and pickett) with new model illustrate that the multiple regression model-new equation (7) is the most accurate model for vp prediction it was able to estimate the vp for the validation data of well-27 with an aare of 0.019 compared with an aare of more than 0.033 for all available correlations nomenclature vp: compressional wave vs.: shear wave velocity uv: ultrasonic velocities sw: water saturation wa: water absorption mr: multiple regressions references [1] r h tatham, t scotellaro and g mavko, "the effect of chemical and physical processes on the acoustic properties of carbonate rocks," leading edge 271982, 2008, pp 10–18. [2] r wilkens, g simmons, and l caruso, "the ratio vp/vs. as a discriminant of composition for siliceous limestones geophysics" 49 1850–60, 1984. [3] k duffaut and m landrø, "vp/vs. ratio versus differential stress and rock consolidation—a comparison between rock models and time-lapse avo data geophysics" 72 c81–94, 2007. [4] e rojas, "vp-vs ratio sensitivity to pressure, fluid, and lithology changes in tight gas sandstones first break" 26 83–86, 2005. [5] yj tawfeeq, ja al-sudani, "digital rock samples porosity analysis by otsu thresholding technique using matlab," iraqi journal of chemical and petroleum engineering, 21 (3), 2020, pp 57-66 [6] m r wyllie, a r gregory, and l w gardner l w, "an experimental investigation of factors affecting elastic wave velocities in porous media geophysics" 23, 1958, pp 459–93. [7] d s raymer, e r hunt and j s gardner, "an improved sonic transit time-to-porosity transform," 21 st annual. meeting of the society of professional well log. 1980. [8] f s anselmetti and g p eberli, “pure appl. geophys. controls on sonic velocity in carbonates," 141, 1993, pp 287–323. [9] eberli g p, baechle g t, anselmetti fs and incze m l 2003 factors controlling elastic properties in carbonate sediments and rocks leading edge 22 654– 60. [10] t vanorio, c scotellaro, and scotellaro g scotellaro, "the effect of chemical and physical processes on the acoustic properties of carbonate rocks leading edge" 27 1040–8, 2008. [11] m. fener, "the effect of rock sample dimension on the p-wave velocity, journal of nondestructive evaluation, 30 (2) (2011), pp. 99-105. [12] m.z.a. duranni, k. willson, j. chen, b. tapp, j. akram "rational rock physics for improved velocity prediction and reservoir properties estimation for granite wash (tight sands) in anadarko basin," texas international journal of geophysics (23) (2014), pp. 1-15. [13] m.n. toksoz, c.h. cheng, a. timur, "velocity of seismic waves in porous rock," geophysics, 41 (1976), pp. 621-645. [14] n sie, "experimental study of water saturation effect on the acoustic velocity of sandstone j. nat. gas sci. eng., 33 (2016), pp. 37-43. [15] l zhang, "engineering properties of rocks" butterworth-heinemann, 2016. [16] w, me t, "evaluation of rock properties using ultrasonic pulse technique and correlating static to dynamic elastic constants." in: 2nd south asian geoscience conference and exhibition, geo india 2011, greater noida, new delhi, india. [17] c kurtulus, s cakir, ac yogurtcuoglu, "ultrasound study of limestone rock physical and mechanical properties." soil mech found eng vol 52, no 6, 2016, pp27–31. [18] pickett g.r., 1963, acoustic character logs and their application in formation evaluation ,j. pet. tech. june, 15 no.6. [19] gist g a, thompson a u, berry "wave velocities in sandstones from elastic network simulations." geophysics 58, no. 3 (1993): 334-343. [20] karami, m., dayani, s., faramarzi, l. "empirical correlations between static and dynamic properties of intact rock." in isrm regional symposium-7th asian rock mechanics symposium. onepetro, 2012. https://library.seg.org/doi/abs/10.1190/1.2967558 https://library.seg.org/doi/abs/10.1190/1.2967558 https://library.seg.org/doi/abs/10.1190/1.2967558 https://library.seg.org/doi/abs/10.1190/1.2967558 https://library.seg.org/doi/abs/10.1190/1.1441598 https://library.seg.org/doi/abs/10.1190/1.1441598 https://library.seg.org/doi/abs/10.1190/1.1441598 https://library.seg.org/doi/abs/10.1190/1.2752175 https://library.seg.org/doi/abs/10.1190/1.2752175 https://library.seg.org/doi/abs/10.1190/1.2752175 https://library.seg.org/doi/abs/10.1190/1.2752175 https://library.seg.org/doi/abs/10.1190/1.2147950 https://library.seg.org/doi/abs/10.1190/1.2147950 https://library.seg.org/doi/abs/10.1190/1.2147950 https://doi.org/10.31699/ijcpe.2020.3.8 https://doi.org/10.31699/ijcpe.2020.3.8 https://doi.org/10.31699/ijcpe.2020.3.8 https://doi.org/10.31699/ijcpe.2020.3.8 https://library.seg.org/doi/abs/10.1190/1.1438493 https://library.seg.org/doi/abs/10.1190/1.1438493 https://library.seg.org/doi/abs/10.1190/1.1438493 https://library.seg.org/doi/abs/10.1190/1.1438493 https://onepetro.org/spwlaals/proceedings-abstract/spwla-1980/all-spwla-1980/spwla-1980-p/19448 https://onepetro.org/spwlaals/proceedings-abstract/spwla-1980/all-spwla-1980/spwla-1980-p/19448 https://onepetro.org/spwlaals/proceedings-abstract/spwla-1980/all-spwla-1980/spwla-1980-p/19448 https://onepetro.org/spwlaals/proceedings-abstract/spwla-1980/all-spwla-1980/spwla-1980-p/19448 https://link.springer.com/article/10.1007/bf00998333 https://link.springer.com/article/10.1007/bf00998333 https://link.springer.com/article/10.1007/bf00998333 https://library.seg.org/doi/abs/10.1190/1.1599691 https://library.seg.org/doi/abs/10.1190/1.1599691 https://library.seg.org/doi/abs/10.1190/1.1599691 https://library.seg.org/doi/abs/10.1190/1.1599691 https://library.seg.org/doi/abs/10.1190/1.2967558 https://library.seg.org/doi/abs/10.1190/1.2967558 https://library.seg.org/doi/abs/10.1190/1.2967558 https://library.seg.org/doi/abs/10.1190/1.2967558 https://link.springer.com/article/10.1007%2fs10921-011-0095-7 https://link.springer.com/article/10.1007%2fs10921-011-0095-7 https://link.springer.com/article/10.1007%2fs10921-011-0095-7 https://www.hindawi.com/journals/ijge/2014/209351/ https://www.hindawi.com/journals/ijge/2014/209351/ https://www.hindawi.com/journals/ijge/2014/209351/ https://www.hindawi.com/journals/ijge/2014/209351/ https://www.hindawi.com/journals/ijge/2014/209351/ https://www.hindawi.com/journals/ijge/2014/209351/ https://library.seg.org/doi/abs/10.1190/1.1440639 https://library.seg.org/doi/abs/10.1190/1.1440639 https://library.seg.org/doi/abs/10.1190/1.1440639 https://www.sciencedirect.com/science/article/abs/pii/s1875510016303018 https://www.sciencedirect.com/science/article/abs/pii/s1875510016303018 https://www.sciencedirect.com/science/article/abs/pii/s1875510016303018 https://books.google.iq/books?hl=en&lr=&id=6ruocgaaqbaj&oi=fnd&pg=pp1&dq=engineering+properties+of+rocks&ots=svxwymhwy6&sig=rgjpbvnjwxu5ncjm-xigydb6y4y&redir_esc=y#v=onepage&q=engineering%20properties%20of%20rocks&f=false https://books.google.iq/books?hl=en&lr=&id=6ruocgaaqbaj&oi=fnd&pg=pp1&dq=engineering+properties+of+rocks&ots=svxwymhwy6&sig=rgjpbvnjwxu5ncjm-xigydb6y4y&redir_esc=y#v=onepage&q=engineering%20properties%20of%20rocks&f=false https://www.searchanddiscovery.com/abstracts/pdf/2011/geo-india/abstracts/ndx_soroush.pdf https://www.searchanddiscovery.com/abstracts/pdf/2011/geo-india/abstracts/ndx_soroush.pdf https://www.searchanddiscovery.com/abstracts/pdf/2011/geo-india/abstracts/ndx_soroush.pdf https://www.searchanddiscovery.com/abstracts/pdf/2011/geo-india/abstracts/ndx_soroush.pdf https://www.searchanddiscovery.com/abstracts/pdf/2011/geo-india/abstracts/ndx_soroush.pdf https://link.springer.com/article/10.1007%2fs11204-016-9352-1 https://link.springer.com/article/10.1007%2fs11204-016-9352-1 https://link.springer.com/article/10.1007%2fs11204-016-9352-1 https://link.springer.com/article/10.1007%2fs11204-016-9352-1 https://onepetro.org/jpt/article/15/06/659/160509/acoustic-character-logs-and-their-applications-in https://onepetro.org/jpt/article/15/06/659/160509/acoustic-character-logs-and-their-applications-in https://onepetro.org/jpt/article/15/06/659/160509/acoustic-character-logs-and-their-applications-in https://library.seg.org/doi/abs/10.1190/1.1443417 https://library.seg.org/doi/abs/10.1190/1.1443417 https://library.seg.org/doi/abs/10.1190/1.1443417 https://onepetro.org/isrmarms/proceedings-abstract/arms712/all-arms712/isrm-arms7-2012-052/39606 https://onepetro.org/isrmarms/proceedings-abstract/arms712/all-arms712/isrm-arms7-2012-052/39606 https://onepetro.org/isrmarms/proceedings-abstract/arms712/all-arms712/isrm-arms7-2012-052/39606 https://onepetro.org/isrmarms/proceedings-abstract/arms712/all-arms712/isrm-arms7-2012-052/39606 q. a. abdul-aziz and h. a. abdul-hussein / iraqi journal of chemical and petroleum engineering 22,3 (2021) 1 9 8 [21] christensen, n.i., stanley, d. seismic velocities and densities of rocks. international handbook of earthquake and engineering seismology 818, 2003, pp 1587–159. [22] s garia. a comprehensive analysis on the relationships between elastic wave velocities and petrophysical properties of sedimentary rocks based on laboratory measurements, 2019. [23] m zoveidavianpoor, a samsuri, and s shadizadeh,. prediction of compressional wave velocity by an artificial neural network using some] well logs in a carbonate reservoir. journal of geophysics and engineering, 2013. [24] hadi,f.a. and nygaard,r .shear wave prediction in carbonate reservoirs can artificial neural network outperform regression analysis, 2018. [25] abdul majeed, r. k., and a.alhaleem, a. a., an accurate estimation of shear wave velocity using well logging data for khasib carbonate reservoir amara oil field, 2020. https://link.springer.com/article/10.1007/s13202-019-0675-0 https://link.springer.com/article/10.1007/s13202-019-0675-0 https://link.springer.com/article/10.1007/s13202-019-0675-0 https://link.springer.com/article/10.1007/s13202-019-0675-0 https://academic.oup.com/jge/article/10/4/045014/5110345?login=true https://academic.oup.com/jge/article/10/4/045014/5110345?login=true https://academic.oup.com/jge/article/10/4/045014/5110345?login=true https://academic.oup.com/jge/article/10/4/045014/5110345?login=true https://academic.oup.com/jge/article/10/4/045014/5110345?login=true https://onepetro.org/armausrms/proceedings-abstract/arma18/all-arma18/arma-2018-905/122672 https://onepetro.org/armausrms/proceedings-abstract/arma18/all-arma18/arma-2018-905/122672 https://onepetro.org/armausrms/proceedings-abstract/arma18/all-arma18/arma-2018-905/122672 https://doi.org/10.31026/j.eng.2020.06.09 https://doi.org/10.31026/j.eng.2020.06.09 https://doi.org/10.31026/j.eng.2020.06.09 https://doi.org/10.31026/j.eng.2020.06.09 q. a. abdul-aziz and h. a. abdul-hussein / iraqi journal of chemical and petroleum engineering 22,3 (2021) 1 9 9 االحصائية بين سرعة الموجة االنضغاطية والخصائص البتروفيزيائية ةتطوير العالق باستخدام بيانات تسجيل االبار لتكوين، الجريبي مكمن االسمري في حقل الفكة قحطان عدنان عبدالعزيز و حسن عبدالهادي عبد الحسين راققسم هندسة النفط، كلية الهندسة، جامعة بغداد، بغداد، الع الخالصة نعاشوعمليات المكمن،تعد بيانات الموجة االنضغاطية مفيدة الستكشاف وتوظيف التكسير المكمن، الحفر وا اليجاد سرعة الموجة أكثرالهيدروليكي، وخطط التطوير لمكمن معين. توجد بعض العالقات الالخطية المعقدة تطور هذه الدراسة العالقات اإلحصائية االنضغاطية وذلك بسبب الطبيعة والسلوك المختلف للمعايير المختلفة. بين سرعة الموجة االنضغاطية والخواص البتروفيزيائية من بيانات تسجيل االبار لنكوين الجريبي في حقل الفكة النفطي في الجنوب الشرقي من العراق باستخدام طريقة انحدار احصائية متعددة المتغيرات للتنبؤ بسرعة الموجة واص البتروفيزيائية وبين أي خاصيتين سرعة موجات القص والمسامية والكثافة وتشبع االنضغاطية من الخ وجود ارتباط خطي قوي بين سرعة الموجة االنضغاطية الدراسةية. وفد استنتجت نالسوائل في ألصخور الكاربو ت الخطية وبين سرعة الموجة االنضغاطية وكثافة الصخور. يمكن استخدام المعادال القصية وسرعة الموجة . أضهرت نتائج أحدهما بداللة االخرىالناتجة لتقدير سرعة الموجة االنضغاطية من سرعة الموجة القصية تحليل االنحدار المتعدد إلى أن الكثافة، المسامية والتشبع بالماء وسرعة موجة القص ترتبط ارتباًطا وثيًقا بالسرعة للموجةاالنضغاطية. الموجة االنضغاطية المتعدد،االنحدار الماء،تشبع المسامية،الكلمات الدالة: available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.21 no.4 (december 2020) 11 – 20 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: maha m. a. alhussaini, , email: maha.alwan@coeng.uobaghdad.edu.iq, name: hassanain a. hassan, email: hassanian.abbas@coeng.uobaghdad.edu.iq, name: nada s. ahmedzeki, email: saadoon @mustaqbal-college.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. experimental investigation of moisture sorption isotherms for mefenamic acid tablets maha m. a. alhussaini a , hassanain a. hassan a , nada s. ahmedzeki b a chemical engineering department / university of baghdad b chemical engineering and petroleum industry department/ al-mustaqbal university college abstract the moisture sorption isotherms of mefenamic acid tablets were investigated by measuring the experimental equilibrium moisture content (emc) using the static method of saturated salt solutions at three temperatures (25, 35, and 45°c) and water activity range from 0.056 to 0.8434. the results showed that emc increased when relative humidity increased and the sorption capacity decreased, the tablets became less hygroscopic and more stable when the temperature increased at constant water activity. the sorption curves had a sigmoid shape, type ii according to brunauer’s classification. the hysteresis effect was significant along with the whole sorption process. the results were fitted to three models: oswin, smith, and guggenhein anderson and de boer. according to the fitting results, the gab model was the most appropriate model to describe the sorption behavior of mefenamic acid; it had a regression coefficient range (0.9803-0.994), %e (0.69-4.06), and low values of see (0.85-2.2). the monolayer moisture content was calculated using the gab model and it was concluded that the tablets should be stored at moisture content equal or slightly higher than (0.2046, 0.1843, and 0.1437 %) for desorption and (0.2073, 0.1269, and 0.1452 %) for adsorption for the three temperatures. keywords: sorption isotherms, equilibrium moisture content, relative humidity, water activity, mathematical modeling, mefenamic acid. received on 08/10/2020, accepted on 17/11/2020, published on 30/12/2020 https://doi.org/10.31699/ijcpe.2020.4.2 1introduction 1.1. sorption isotherms sorption isotherms are known as a classical approach technique to describe the relationship between the relative humidity and equilibrium moisture content (emc) at constant temperature and pressure. it is an important characteristic to describe the interaction between components and water; it gives information in the modeling of the drying process, predicting the product shelf life, selection of the material packaging and storage conditions [1]. adsorption isotherm has many benefits in wastewater treatment i.e. removal of fluoroquinolones antibiotic by adsorption using activated carbon [2, 3]. if a sample comes into equilibrium with the surrounding atmosphere, the water activity of a sample becomes equal to the relative humidity of the surrounding or in which it is stored. when this equilibrium is reached, the material neither loses nor gains moisture over time. the product moisture loss or gain to/from depends on the environment relative humidity, temperature, and time [4]. moisture sorption isotherms curves can be divided into sections that describe the material behavior and help to understand the changes that taking place in the product, these sections are not static, they change according to the experimental conditions and material kind. desorption data is used for drying analysis and adsorption data for choosing the storage conditions [5, 6]. the moisture content reached equilibrium when the partial pressure of water vapor in the material became equal to the partial pressure of water vapor of surrounding air; it is the limiting moisture content after the exposure of a product to a fixed condition for a very long time. emc is useful for determining water gain or loss under certain conditions of relative humidity and temperature, it is directly related to storage and drying ventilation. there are two equilibrium moisture contents at constant air relative humidity and temperature depending on the experimental conditions, whether the moisture content of the material is higher or lower than the equilibrium for environmental conditions (desorption or adsorption) [6, 7]. the water activity (aw) concept has been used as a reliable practical indication of the quality of a material. it is a thermodynamic property and defined as the ratio of the equilibrated vapor pressure to the saturation vapor pressure of pure water at the same temperature. its value ranges 0˂ aw <1and can be expressed as: 𝑎𝑤 = 𝑃 𝑝° (1) 𝑎𝑤 = 𝐸𝑅𝐻 100 (2) http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:maha.alwan@coeng.uobaghdad.edu.iq mailto:a.alnaama53@gmail.com http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2020.4.2 m. m. a. alhussaini et al. / iraqi journal of chemical and petroleum engineering 21,4 (2020) 11 20 12 the water activity changes with temperature and the products are exposed to a wide range of humidity and temperatures during transporting and storage. temperature affects the water molecule's mobility and the dynamic equilibrium between water vapor and adsorbents phases, thus both relative humidity and temperature must be specified for the sorption process. for certain water activity, the values of equilibrium moisture content, in desorption isotherm is higher than in adsorption [5, 6, 8]. moisture sorption hysteresis is defined as the phenomena where two different paths are noticed between adsorption and desorption isotherms [9]. the hysteresis occurrence indicates that either the desorption or adsorption curve was not a true equilibrium or a composition in the material was in a changed state during the process [10]. the main factors affecting hysteresis are isotherm temperature, the composition of the material, storage time before measurement, drying temperature, pretreatments, and the number of successive desorption cycles [11]. the width and shape of sorption hysteresis loops were dependent on material type and temperature [12]. the reduction in the hysteresis loop area indicates a decrease in the sorption process of free energy and an improvement in stability [13]. the hysteresis occurs due to non-reversible changes in the structure and non-equilibrium effects, during adsorption, the porous began to swell up because of the increase in relative humidity and when partial pressure of the water vapor became higher than the vapor pressure of the capillaries, the water moved toward the interior of the pore. during desorption, the pores were saturated at the beginning then water diffusion occurred from the periphery to the surface and that when the partial pressure of the water vapor in the surrounding air became lower than the vapor pressure inside the capillary. the value of hysteresis is the difference of equilibrium moisture content between desorption and adsorption [14, 15, 16]. the isotherm curves are important to determine the stability criteria and prevent degradation for moisturesensitive products i.e. pharmaceuticals. manufacturers must specify not only the amount of moisture that exists in the products but also the moisture desorptionadsorption behavior as their products are exposed to humidity during manufacturing, storage, and in end-use. [17]. the water in pharmaceutical products comes either from the exposure to high relative humidity or as the residual water from processing, it may affect the physical and chemical stability of products. for pharmaceutical products, stability is a critical quality and it varies with time under the effect of a variety of environmental factors such as; humidity, light, and temperature. so, the isotherm curves can be considered as a key factor to control the moisture sorption by the packages of products during shelf life, the container permeability and can be used to predict the product's stability over time in drying processes [18, 19]. many authors have studied and modeled the emc of food but few for pharmaceuticals [13]. the experimental emc data of the tablets were determined using the static method. it is based on generating a fixed relative humidity environment using saturated salt solutions, where the samples are brought to equilibrium in a closed system of known relative humidity [16]. the relative humidity value depends on the salt kind. the method requires temperature stability and uniformity. it has many advantages: low cost of salts, the ease of handling, and maintenance of the humidity conditions but the main disadvantages are time and laborconsuming [17, 20]. the desiccator method with the loss on drying measurement can be considered a convenient technique for studying the emc of tablets [18]. tablet is the most preferred oral dosage form, due to many advantages offered to formulators as well as physicians and patients. mefenamic acid tablets belong to a group of medicines named, non-steroidal anti -inflammatory drugs (or nsaids), these medicines used for pain-relieving and inflammation*. 1.2. mathematical models of sorption isotherms the fitting of sorption results can be used as a tool in optimization and processing design, to solve packaging problems, an instance in drying, predicting shelf life stability, modeling moisture changes which might occur during drying, and ingredient mixing predictions. the models should meet the following requirements [4, 21]: 1for functional applications, especially, drying and storing. 2 the relation should describe the experimental curves mathematically. 3the simplicity of the model that describes the process must be obtained along with parameters limitation, as much as possible. 4the parameters of the model should have a physical background. the models used in this study were: oswin, smith and guggenhein anderson and de boer (gab), their equations are shown in table 1 [5, 6, 7, 22, and 23]. table 1. sorption isotherms models model name model equation model parameters oswin 𝑀 = 𝑚 [ 𝑎𝑤 1− 𝑎𝑤 ] 𝑛 𝑚, 𝑛: constants smith 𝑀 = 𝐾2 − 𝐾1 ln(1 − 𝑎𝑤 ) 𝐾1, 𝐾2: constants gab m = 𝑀𝑚 𝐶 𝐾 𝑎𝑤 (1 − 𝐾 𝑎𝑤 )(1 + (𝐶 − 1))𝐾 𝑎𝑤 mm monolayer moisture content c guggenheim constant k constant m. m. a. alhussaini et al. / iraqi journal of chemical and petroleum engineering 21,4 (2020) 11 20 13 three statistical parameters were used to evaluate the ability of a model to fit the experimental results, namely: the coefficient of regression (r 2 ), generally the values ≥ 0.98 is acceptable. the mean relative percent error (%e), eq.(3), values lower than 5 indicate a good fit, values between 5 and 10, indicate a reasonable adjustment, and values higher than 10 indicate a poor fit. the standard error of estimate (see), eq.(4), the model´s ability to describe a certain physical process has an inverse proportional to see, low values of see indicate a good fit of the model to the data [15, 23, 24]. % e = 100 𝑁 ∑ | 𝑀𝑖−𝑀𝑖 ^ 𝑀𝑖 | 𝑁 𝑖=1 (3) 𝑆𝐸𝐸 = √ ∑ (𝑀𝑖−𝑀𝑖 ^)2𝑁𝑖=1 𝑑𝑓 (4) where: 𝑀𝑖 : experimental equilibrium moisture content at i-th observation (g water/g dry solid). 𝑀𝑖 ^: predicted equilibrium moisture content at the same observation (g water/g dry solid). 𝑁 : number of data points. 𝑑𝑓 : degree of freedom. the aim of this study was to 1determine the characteristics of sorption isotherms of mefenamic acid at 25, 35, and 45°c and water activity range of (0.056 to 0.8434). 2select a suitable model that describes the sorption processes. 3calculate the monolayer moisture content and choose the suitable storing conditions of moisture content and relative humidity. 2materials and method 2.1. materials and chemicals the moisture sorption isotherms of mefenamic acid were studied by measuring the equilibrium moisture content at three temperatures ( 25, 35, and 45ْc) using nine saturated salt solutions with water activity ranges from 0.056 to 0.8434 for both sorption processes leading to a total number of experiments of 54. mefenamic acid tablets were used in this study. there is a caution that the tablets should be kept in a cool dry place where the temperature is below 30°c because heat and humidity destroy the drug*. temperatures choice was according to the local weather conditions and they were suitable because they offered true ones. for the desorption process, the material was hydrated well with distilled water at room temperature and the initial moisture content was calculated and recorded as 30% on a dry basis. for the adsorption process, the material was dried in a circulating air oven for 24 hours at 25 ْْc until the final moisture content of 0.8 % on a dry basis was reached [19]. saturated salt solutions were used to generate the desired relative humidity. they were prepared at ambient temperature by dissolving pure salt in boiling water, stirred continuously for two hours using a magnetic stirrer with the addition of excess salt to ensure the saturation, then left to cool. the solutions were placed in desiccators at the desired temperature for seven days before the sorption experiment [5]. the proportions are shown in table 2 [25]. it has been noted that temperature affects the relative humidity [27, 28]. the relative humidity values at the three temperatures for the different kinds of salt solutions are shown in table 3 [25]. table 2. proportions for saturated salt solutions preparation salt kind salt (g.) distilled water (ml) naoh 36 100 licl 42.5 75 mgcl2 12.5 100 k2co3 45.0 100 mg(no3)2 15.0 100 nabr 40.0 100 ki 25.0 100 nacl 30.0 100 kcl 40 100 table 3. relative humidity at different temperatures salt solution temperature ºc 25 35 45 naoh % relative humidity 8.24 6.92 5.6 licl 11.3 11.25 11.16 ch3cook 0.225 0.209 0.193 mgcl2 32.78 32.05 31.10 k2co3 44.30 43.60 43.2 mg(no3)2 52.89 49.91 46.93 ki 68.86 66.96 65.26 nacl 75.29 74.87 74.52 kcl 84.34 82.95 81.74 2.2. method the sample weight had a considerable effect on the time required to reach equilibrium because of the time needed for molecular diffusion through the sample interior structure, so samples of 3g each were weighted using a balance of ± 0.0001g sensitivity model (startuos) and placed in crucibles over the support inside desiccators [4]. desiccators were placed in an oven at the controlled and desired temperature, allowed to reach equilibrium. the samples were weighted periodically every 24 hours until the change between three successive readings was less than 0.001 g. the emc of samples was determined by loss on drying method (lod) at 105 ºc for 24hr [1]. this procedure was repeated for adsorption-desorption processes for the nine kinds of salts and the three temperatures. [5, 24, 26] . m. m. a. alhussaini et al. / iraqi journal of chemical and petroleum engineering 21,4 (2020) 11 20 14 3results and discussion 3.1. experimental equilibrium moisture content results, emc, (on dry basis) were plotted against water activity for desorption-adsorption processes at 25, 35, and 45 ºc and presented in fig. 1fig. 5. fig. 1. sorption isotherms of mefenamic acid at 25c fig. 2. sorption isotherms of mefenamic acid at 35c fig. 3. sorption isotherms of mefenamic acid at 45ْc fig. 4. desorption isotherm of mefenamic acid at different temperatures fig. 5. adsorption isotherm of mefenamic acid at different temperatures fig. 1, fig. 2 & fig. 3 showed that the emc increased with the increase of water activity at a constant temperature for both sorption processes that agreed with [4, 5, 17, and 24]. fig. 4 & fig. 5, showed that the increase in temperature at constant aw caused to decrease the emc, which means the sorption capacity decreased and the material became less hygroscopic because when temperature raised, the degree of disorder of water molecules present at the adsorbent surface increased, they became more active leading to instability and breakage of intermolecular connections between sorption sites and water molecules, that increased the intermolecular distances, decreased the attractive forces, the water easily break away from binding sites allowing water vaporization consequently decreasing emc and the degree of water sorption at a given water activity. this behavior is typical for pharmaceuticals and agreed with [6, 15, 20, 22, and 24]. at constant m, the increase in temperature caused to lower the isotherm curves, for a higher temperature the product had a higher value of relative humidity thereby making it more susceptible to degradation and that agreed with [30].[33] concluded that for each product, there is an optimum range of water activity values for the best storage conditions. the values of emc for desorption were higher than those for adsorption at constant water activity, this behavior was an indication of the appearance of hysteresis phenomenon and it was noticed for other pharmaceuticals [13, 16, 18, 28]. fig. 1-fig. 3 showed that the hysteresis magnitudes increased as temperature increased, the hysteresis effect was noticed during the entire water activity range for the three temperatures, at t=25ْc it decreased nearly at aw= 0.7529, at t=35 ْc, it was in increasing form for the whole range of water activity then decreased at aw= 0.7452 and at t=45 ْc it was in increasing form. according to [12] the large hysteresis is associated with tightly bound water and the large magnitude of hysteresis loops is due to the difference in the distribution of pore size. [15] explained this phenomenon occurrence by capillary condensation theory: the material porous is formed by narrow capillaries of small diameters, they control capillary emptying during desorption process, causing the relative humidity reduction, while during m. m. a. alhussaini et al. / iraqi journal of chemical and petroleum engineering 21,4 (2020) 11 20 15 adsorption process, moisture gained, capillaries were not filled as before desorption, lead to a lower value of moisture content as before. the isotherm curves were of type ii according to brunauer`s classification, they had the s-shape, sigmoidal, this shape is common for hygroscopic products, and indicated the formation of a well-defined monolayer [13, 14]. it is caused by synergistic effects of the capillarity, raoult’s law, and moisture interactions at the surface of the material [15]. there was a slight increase in emc at a low and intermediate range of aw. two bending regions can be noticed that agreed with [5, 6], the first at aw equals to (0.113, 0.1125, 0.1116) for the three temperatures, where water sorption was in the monolayer region, the second at aw of (0.5289, 0.4991, 0.4693) where the isotherm curve had up-ward slope which represented the sorption of bound water, this emc is called the critical equilibrium moisture content, it can be chosen to guarantee well product preservation because water activity value is suitable to prevent degradation, the values were: for desorption (20.8, 19.3, 17.2 %), for adsorption (18.6, 15.6,13.1 %). as aw increased, the emc increased more sharply due to capillarity and physicochemical changes, such as multilayers creation and the filling of pores then followed by filling of larger pores and solutes dissolution. this behavior was the identification of type ii isotherm according to brunauer's classification [15, 23]. [31] concluded that the shape of sorption isotherms curves is characterized by the states of system constituents. 3.2. fitting of experimental sorption isotherms to the models the experimental results of sorption isotherms of mefenamic acid at 25, 35and 45 °c have been fitted to three models (oswin, smith, and gab) using microsoft excel 2010, to select the best model that describes the processes. the results are shown in table 4 and fig. 6fig. 14 a. oswin model fitting results were obtained by linear regression of ln m versus ln [aw/1-aw]. the results are shown in figs.6, 7 &8. fig. 6. fitting of oswin model to sorption isotherms at 25ْc fig. 7. fitting of oswin model to sorption isotherms at 35ْc fig. 8. fitting of oswin model to sorption isotherms at 45ْc b. smith model fitting results were obtained by linear regression of ln m versus ln (1-aw). the results are shown in figs.9,10 & 11. fig. 9. fitting of the smith model to sorption isotherms at 25ْc fig. 10. fitting of the smith model to sorption isotherms at 35ْc m. m. a. alhussaini et al. / iraqi journal of chemical and petroleum engineering 21,4 (2020) 11 20 16 fig. 11. fitting of the smith model to sorption isotherms at 45ْc c. guggenheim , anderson and de -boer model (gab ) the gab model was transformed to quadratic form, eq. (5) the constants 𝛼, β 𝑎𝑛𝑑 𝛾, and the regression coefficients were obtained by non-linear regression of the second degree polynomial from the plot of ( 𝑎𝑤 𝑀𝑤 vs aw). the model constants were calculated using eq. 6, eq. 7, eq. 8, and eq.9 [5, 7, 28, 30]. the results are shown in table 4 and fig. 13, fig. 14. 𝑎𝑤 𝑀𝑤 = 𝛼 𝑎2 𝑤 + β 𝑎𝑤 + 𝛾 (5) α = k mw ( 1 c − 1) (6) β = 1 mw [1 − 2 c ] (7) γ = 1 mw. c. k (8) mm = √ 1 β2−4αγ (9) fig. 12. fitting of gab model to sorption isotherms at 25  c fig. 13. fitting of gab model to sorption isotherms at 35  c fig. 14. fitting of gab model to sorption isotherms at 45  c table 4. fitting results and statistical parameters model temperature 25  c 35  c 45  c oswin desorption n 0.3668 0.4318 0.4847 m 2.9035 2.814 2.7154 r 2 0.9579 0.9568 0.9768 %e 0.59 0.76 0.23 see 1.7 2.2 2.2 adsorption n 0.4612 0.501 0.4908 m 2.7567 2.6606 2.505 r 2 0.9484 0.9784 0.9914 %e 3.8 0.08 0.35 see 1.8 1.8 1.7 smith desorption k1 -12.853 -13.659 -14.074 k2 8.5735 6.7349 5.1709 r 2 0.9339 0.94 0.9457 %e 4.3 7.4 8.8 see 2.1 1.4 1.9 adsorption k1 -13.958 -14.286 -12.599 k2 5.7933 4.3175 3.4634 r 2 0.955 0.9756 0.9843 %e 6.4 0.40 5.0 see 1.9 2.1 0.85 gab desorption mm 20.46 18.43 14.37 c 9.24 6.97 7.69 k 0.48 0.55 0.63 r 2 0.994 0.9833 0.9858 %e 0.7 0.69 1.9 see 0.52 0.65 0.44 adsorption mm 20.73 12.69 14.52 c 4.12 5.86 7.93 k 0.58 0.72 0.54 r 2 0.9843 0.9823 0.9803 %e 4.06 2.1 3.6 see 0.69 0.44 0.57 from the results shown in table 4, it can be noted that the fitting results of oswin and gab models were better than that of smith. the regression coefficients for gab and oswin models ranges (0.98030.994) and (0.94840.9914) for both sorption processes, for gab they were higher than 0.98 and better than oswin. the mean relative percent deviation values for both of them were less than 5% and that was an indication of the well-fitting of the two models. for the smith model, the regression coefficients were less than 0.98, and %e was less than 10 indicate a reasonable adjustment. m. m. a. alhussaini et al. / iraqi journal of chemical and petroleum engineering 21,4 (2020) 11 20 17 the see values for gab were lower than the other two models and ranges (0.85-2.2). so the gab is better for describing sorption isotherms of mefenamic acid tablets. the gab model can be used over a wide range of water activity up to 0.9; its application is more advantageous than other models since its parameters have physical meanings allowing a detailed study of mass and heat transfer that occur during desorption-adsorption processes [4, 5, 16 and 25]. from the results shown in table .4, the gab constants were temperature dependent that agreed with [22, 28]. the first constant of the gab model is the monolayer moisture content (mm), it is a critical point of the sorption isotherm curve that represents the water content when the entire surface is covered with moisture, bears significant consequences for storage conditions of products. it is the moisture content for the maximum shelf stability used to control the quality and to extend the self-life of products by storing at or slightly above mm value [3, 4, 5, 29]. at mm, the physical changes, oxidation, and degradation are slow down. changes occur when the moisture content value of a product is lower than mw [1, 22]. it is generally decreased with temperature and that agreed with [7, 23, 27]. the estimated values of %mm on a dry basis using the gab model are presented in table 5. table 5. monolayer moisture content (% d. b.) at different temperatures temperature (ْc) desorption adsorption 25 20.46 20.73 35 18.43 12.69 45 14.37 14.52 from table 5, as the temperature increased from 25 to 45 ◦ c, mw values decreased from (20.46 to 14.37 % d.b.) for desorption and (20.73 to 14.52 % d.b.) for adsorption and that explained due to the gained kinetic energy by the molecules which caused to loosen the attractive forces, allowing some molecules of the water to break away from their sorption sites, also a reduction in the number of active sites and decrease in the available specific surface area that caused to decrease the mm that agreed with [4, 5, 22, 23]. the tablets should be stored at moisture content slightly higher than (0.2046, 0.1843, and 0.1437 %) for desorption and (0.2073, 0.1269, and 0.1452 %) for adsorption for the three temperatures. it can be noted that the monolayer moisture content values were close to the concluded values of critical emc from figs 1-5 that discussed previously in section 3.1. [32] confirmed this conclusion that the mm and critical emc are important for maintaining shelf stability. the second constant, the guggenheim constant (c), represents the enthalpy change, it is related to the different chemical potentials between the monolayer and the upper layers and should be higher than zero. when c ≥ 2, the sorption curves had a sigmoid shape, type ii of brunauer`s classification. as shown in table 4, the c values were greater than 2 and that ensures the sorption curves were of type ii [5,13, 21, 23]. there was an increase in c values with increasing temperature, for adsorption from (4.12 7.93), and for desorption ( 6.97 to7.69) that ensures the constant is temperature dependent [28]. the increase was a result of the strong binding of water monolayer with the primary sorption sites; the temperature increase caused a gain in kinetic energy which increase enthalpy and more moisture loss at a higher temperature. the values of c for desorption were higher than that for adsorption, which means the water monolayer removal from the structure of the material required more heat [22, 27]. the third constant, k is the degree of freedom of water molecules, it is related to multilayer properties, between the upper layers and free water, k values are always less than 1.0, values greater than one indicate infinite sorption which is physically unsuitable. as shown in table 4.the range of k values was less than unity and that in agreement with the assumption of the gab model that the multilayer properties were between the monolayer and bulk liquid[28]. k values increased with temperature from (0.48 to 0.63) for desorption and (0.58 to 0.72) for adsorption, this increase was an indication that the molecules in the multilayer became more entropic which agreed with its physical meaning [9, 21 23, 24, 27]. 4conclusions the sorption isotherms of mefenamic acid were determined at three temperatures (25, 35, and 45ºc) using the standard static method. equilibrium moisture content was directly proportional to relative humidity (water activity) at a constant temperature. the sorption capacity decreased with an increase in temperature at constant water activity, the tablets became less hygroscopic and more stable with the rise of sorption temperatures at constant water activity. the sorption isotherms had a sigmoid shape, with type ii according to brunauer’s classification. the hysteresis phenomena were significant at the three temperatures for both sorption processes. the monolayer moisture content decreased with the temperature increase of sorption processes. the tablets should be stored at moisture content slightly higher than (0.2046, 0.1843, and 0.1437 %) for desorption and (0.2073, 0.1269, and 0.1452 %) for adsorption for the three temperatures. the gab model was the best model to describe the sorption processes, and its constants were temperature dependent. acknowledgment the experimental study was conducted in the laboratories of the chemical engineering department/engineering college/baghdad university. m. m. a. alhussaini et al. / iraqi journal of chemical and petroleum engineering 21,4 (2020) 11 20 18 nomenclature a w water activity dimensionless d.b. on a dry basis emc equilibrium moisture content,% g h2o /g dry solid erh equilibrium relative humidity e mean relative deviation,% k1, k2 smith model constants. lod loss on drying. m equilibrium moisture content, % g h2o /g dry solid m ^ predicted moisture content, % g h2o /g dry solid mm monolayer moisture content, % g h2o /g dry solid mm, c, k gab model constants m, n oswin model constants p vapor pressure of water in a solid material at t. n/m 2 pْ vapor pressure of pure water at t. n/m 2 r 2 coefficient of regression see the standard error of estimate greek letters α, β, γ constants of gab model (in quadric form). references [1] toshkov n., simitchiev a., nenov v. , panchev i. ,"effect of the quantity of cocoa shells and moisture content on sorption characteristics of extrudates from corn semolina", scientific works of university of food technologies , vol. 66, no.1, 2020. [2] z. abdulrazak n., “sorption of nitrate salts from wastewater without and with modification orange peel”, ijcpe, vol. 17, no. 3, pp. 109-116, sep. 2016. [3] ammar s. a., muthana j.a.,teeba m.d.," adsorption of fluoroquinolones antibiotics on activated carbon by k2co3 with microwave assisted activation", ijcpe, vol.17,no.2,15-23,2016. [4] singh a.k., kumari n., "moisture sorption isotherm characteristics of ground flaxseed". j. food process technology, vol. 5, no. 4, 2014. [5] tontul s.a. ," moisture sorption isotherm, is-steric heat and adsorption surface area of whole chia seeds", lwt food science and technology, november, 2020. [6] lodredd y.a., hernandez a.r., velazquez1 g., "modeling the effect of temperature on the water sorption isotherms of chitosan films rocio , food science and technology, vol.37,no.1, 112-118, , 2017. [7] ahmed w., aziz m.g. , and islam n. ,"modeling of moisture adsorption isotherm of selected commercial flours of bangladesh", the agriculturists ,vol. 16,no.2, 35-42 ,2018. [8] nakagawa h., oyama t. ," molecular basis of water activity in glycerol-water mixtures ,physical chemistry and chemical physics, vol.7 ,article 731,nov.,2019. [9] gálvez a., lópez j., kong ah-hen k., "thermodynamic properties, sorption isotherms and glass transition temperature of cape gooseberry", food technol. biotechnol , vol.52 , no.1 83–92 , 2014. [10] rahman m., shyams s., labuza t.p., ”measurement of water activity using isopiestic method “,current protocols in food analytical chemistry, 2000 . [11] esquijarosa j.a., haza u.j. and leroux g.c. ,"behavior and modeling of humidity isotherm of mangifera indica l(vimang) powder",world applied sciences journal,vol.11, no.12, pp 1504-1509,2010. [12] lagoudaki m.,demertzis p.g. ,"equilibrium moisture characteristics of food-hysteris effect and isotherm models",lebensmittel technologie ,vol.26,no.4,1993. [13] alwan m.m., "equilibrium moisture sorption isotherms of aspirin", journal of engineering, vol.19, no.4, 2013. [14] ethmane c.s., kane e., kouhila m., lamharrar a., a. idlimam and lamharrar a.," moisture sorption isotherms and thermodynamic properties of tow mints: mentha pulegium and mentha rotundifolia", revue des energies renouvelables vol. 11 no.2 ,pp. 181 – 195,2008. [15] zeymer j.s., corrêa p.c. , oliveira g.h. , baptestini f.m. , campos r.c.,"mathematical modeling and hysteresis of sorption isotherms for paddy rice grains", eng. agríc., vol.39, no.4, july/aug, 2019. [16] hawa l.c., aini k.n., maharani d. m. and susilob., "moisture sorption isotherm and isosteric heat of dried cabya ( piper retrofractum vahl) powder", international conference of sustainability agriculture and biosystem,2020. [17] bell l. n., labuza t. p.," determination of moisture sorption isotherms. moisture sorption: practical aspects of isotherm measurement and use, the american association of cereal chemists, “2 nd edition, aacc egan press., 33-56, 2000. [18] yanxia l., yeshwant d. and yisheng c. , "a study on moisture isotherms of formulations: the use of polynomial equations to predict the moisture isotherms of tablet products, pharm science tech. vol. 4 ,no. 59, 2003. https://www.researchgate.net/profile/nesho_toshkov/publication/341343311_effect_of_the_quantity_of_cocoa_shells_and_moisture_content_on_sorption_characteristics_of_extrudates_of_corn_semolina/links/5ebb9e81299bf1c09ab94097/effect-of-the-quantity-of-cocoa-shells-and-moisture-content-on-sorption-characteristics-of-extrudates-of-corn-semolina.pdf https://www.researchgate.net/profile/nesho_toshkov/publication/341343311_effect_of_the_quantity_of_cocoa_shells_and_moisture_content_on_sorption_characteristics_of_extrudates_of_corn_semolina/links/5ebb9e81299bf1c09ab94097/effect-of-the-quantity-of-cocoa-shells-and-moisture-content-on-sorption-characteristics-of-extrudates-of-corn-semolina.pdf https://www.researchgate.net/profile/nesho_toshkov/publication/341343311_effect_of_the_quantity_of_cocoa_shells_and_moisture_content_on_sorption_characteristics_of_extrudates_of_corn_semolina/links/5ebb9e81299bf1c09ab94097/effect-of-the-quantity-of-cocoa-shells-and-moisture-content-on-sorption-characteristics-of-extrudates-of-corn-semolina.pdf https://www.researchgate.net/profile/nesho_toshkov/publication/341343311_effect_of_the_quantity_of_cocoa_shells_and_moisture_content_on_sorption_characteristics_of_extrudates_of_corn_semolina/links/5ebb9e81299bf1c09ab94097/effect-of-the-quantity-of-cocoa-shells-and-moisture-content-on-sorption-characteristics-of-extrudates-of-corn-semolina.pdf https://www.researchgate.net/profile/nesho_toshkov/publication/341343311_effect_of_the_quantity_of_cocoa_shells_and_moisture_content_on_sorption_characteristics_of_extrudates_of_corn_semolina/links/5ebb9e81299bf1c09ab94097/effect-of-the-quantity-of-cocoa-shells-and-moisture-content-on-sorption-characteristics-of-extrudates-of-corn-semolina.pdf http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/218 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/218 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/218 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/78 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/78 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/78 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/78 https://d1wqtxts1xzle7.cloudfront.net/43917194/moisture_sorption_isotherm_characteristi20160320-27508-cfdwqe.pdf?1458475604=&response-content-disposition=inline%3b+filename%3dmoisture_sorption_isotherm_characteristi.pdf&expires=1608028869&signature=ut7ji7u70r~5ekxxf2eibdonh9yozwohrmlb3ehi-fy-pob3f7jj7bgnk9mm5jbw5eyjqoseaip42rgov7w8fvtv3mmqgihrtd3namtdqthmwqozi-errdpxy8ycw2sd36jcyhsgnyzqqt1ol66wzen~mphrlc1plnauflz-eq6vwyhu~xm0imoc7cvrpxcckc0yxpwvhr30katpq6rlsncemjigdqmtd~thwy~qc3uprqt4bog3xqnhvqefmb~v8ifii8do-1beifihcwh~6dfgcfzikqkdxosubdvjnesycbnacvz5itgwkgz5t8tw8mt9yy6eg6jkluu0gkf75a__&key-pair-id=apkajlohf5ggslrbv4za 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https://d1wqtxts1xzle7.cloudfront.net/43917194/moisture_sorption_isotherm_characteristi20160320-27508-cfdwqe.pdf?1458475604=&response-content-disposition=inline%3b+filename%3dmoisture_sorption_isotherm_characteristi.pdf&expires=1608028869&signature=ut7ji7u70r~5ekxxf2eibdonh9yozwohrmlb3ehi-fy-pob3f7jj7bgnk9mm5jbw5eyjqoseaip42rgov7w8fvtv3mmqgihrtd3namtdqthmwqozi-errdpxy8ycw2sd36jcyhsgnyzqqt1ol66wzen~mphrlc1plnauflz-eq6vwyhu~xm0imoc7cvrpxcckc0yxpwvhr30katpq6rlsncemjigdqmtd~thwy~qc3uprqt4bog3xqnhvqefmb~v8ifii8do-1beifihcwh~6dfgcfzikqkdxosubdvjnesycbnacvz5itgwkgz5t8tw8mt9yy6eg6jkluu0gkf75a__&key-pair-id=apkajlohf5ggslrbv4za https://www.sciencedirect.com/science/article/abs/pii/s0023643819312010 https://www.sciencedirect.com/science/article/abs/pii/s0023643819312010 https://www.sciencedirect.com/science/article/abs/pii/s0023643819312010 https://www.sciencedirect.com/science/article/abs/pii/s0023643819312010 https://www.scielo.br/scielo.php?pid=s0101-20612017000100112&script=sci_arttext https://www.scielo.br/scielo.php?pid=s0101-20612017000100112&script=sci_arttext https://www.scielo.br/scielo.php?pid=s0101-20612017000100112&script=sci_arttext https://www.scielo.br/scielo.php?pid=s0101-20612017000100112&script=sci_arttext https://www.scielo.br/scielo.php?pid=s0101-20612017000100112&script=sci_arttext https://www.banglajol.info/index.php/agric/article/view/40341 https://www.banglajol.info/index.php/agric/article/view/40341 https://www.banglajol.info/index.php/agric/article/view/40341 https://www.banglajol.info/index.php/agric/article/view/40341 https://www.frontiersin.org/articles/10.3389/fchem.2019.00731/full https://www.frontiersin.org/articles/10.3389/fchem.2019.00731/full https://www.frontiersin.org/articles/10.3389/fchem.2019.00731/full https://www.frontiersin.org/articles/10.3389/fchem.2019.00731/full https://hrcak.srce.hr/index.php?show=clanak&id_clanak_jezik=175257 https://hrcak.srce.hr/index.php?show=clanak&id_clanak_jezik=175257 https://hrcak.srce.hr/index.php?show=clanak&id_clanak_jezik=175257 https://hrcak.srce.hr/index.php?show=clanak&id_clanak_jezik=175257 https://hrcak.srce.hr/index.php?show=clanak&id_clanak_jezik=175257 https://currentprotocols.onlinelibrary.wiley.com/doi/abs/10.1002/0471142913.faa0203s00 https://currentprotocols.onlinelibrary.wiley.com/doi/abs/10.1002/0471142913.faa0203s00 https://currentprotocols.onlinelibrary.wiley.com/doi/abs/10.1002/0471142913.faa0203s00 https://www.cabdirect.org/cabdirect/abstract/20113133897 https://www.cabdirect.org/cabdirect/abstract/20113133897 https://www.cabdirect.org/cabdirect/abstract/20113133897 https://www.cabdirect.org/cabdirect/abstract/20113133897 https://www.iasj.net/iasj?func=article&aid=70795 https://www.iasj.net/iasj?func=article&aid=70795 https://www.iasj.net/iasj?func=article&aid=70795 https://www.cder.dz/vlib/revue/pdf/v011_n2_texte_2.pdf https://www.cder.dz/vlib/revue/pdf/v011_n2_texte_2.pdf https://www.cder.dz/vlib/revue/pdf/v011_n2_texte_2.pdf https://www.cder.dz/vlib/revue/pdf/v011_n2_texte_2.pdf https://www.cder.dz/vlib/revue/pdf/v011_n2_texte_2.pdf https://www.cder.dz/vlib/revue/pdf/v011_n2_texte_2.pdf https://www.scielo.br/scielo.php?pid=s0100-69162019000400524&script=sci_arttext https://www.scielo.br/scielo.php?pid=s0100-69162019000400524&script=sci_arttext https://www.scielo.br/scielo.php?pid=s0100-69162019000400524&script=sci_arttext https://www.scielo.br/scielo.php?pid=s0100-69162019000400524&script=sci_arttext https://iopscience.iop.org/article/10.1088/1755-1315/515/1/012029/meta https://iopscience.iop.org/article/10.1088/1755-1315/515/1/012029/meta https://iopscience.iop.org/article/10.1088/1755-1315/515/1/012029/meta https://iopscience.iop.org/article/10.1088/1755-1315/515/1/012029/meta https://iopscience.iop.org/article/10.1088/1755-1315/515/1/012029/meta https://www.bcin.ca/bcin/detail.app?id=243338 https://www.bcin.ca/bcin/detail.app?id=243338 https://www.bcin.ca/bcin/detail.app?id=243338 https://www.bcin.ca/bcin/detail.app?id=243338 https://www.bcin.ca/bcin/detail.app?id=243338 https://link.springer.com/article/10.1208/pt040459 https://link.springer.com/article/10.1208/pt040459 https://link.springer.com/article/10.1208/pt040459 https://link.springer.com/article/10.1208/pt040459 https://link.springer.com/article/10.1208/pt040459 m. m. a. alhussaini et al. / iraqi journal of chemical and petroleum engineering 21,4 (2020) 11 20 19 [19] robert l. hassel, moisture sorption analysis of pharmaceuticals, ta instruments usa, 2016. [20] bennamoun l., tagne m.s. and ndukwu m.c.," simulation of storage conditions of mixed biomass pellets for bioenergy generation: study of the thermodynamic properties, energies, vol.13, 2544, 14 pages, 2020. [21] mania p., majka j., zborowska m., "the effect of thermo-mechanical treatment of moso bamboo phyllostachys pubescens) on its sorption and physicomechanical properties" , drvna industrija vol.3, no.70, 265-272 ,2019. [22] baptestini f. m. , corrêa3 p.c. , ramos a.m. , junqueira m.s. and zaidan i.r., "gab model and the thermodynamic properties of moisture sorption in soursop fruit powder, rev. ciênc. agron., v. 51, no. 1, 2020. [23] vasilea f.e., judisa m. , mazzobre m.f," moisture sorption properties and glass transition temperature of a nonconventional exudate gum ( prosopis alba) from northeast argentine", food research international, vol.,no.131, 2020. [24] durakova a. , bogoeva a., krasteva r. , "sorption characteristics of subtropical fruit – lucuma powder", materials science and engineering, conference, 2019. [25] greenspan l.” humidity fixed points of saturated aqueous solutions” , journal of research of the national bureau of standards, vol.81, no.1, pp.89-96, 1977. [26] zeymer j.s. , corrêa1 p.c. , horta g.h. , viana m.e. , magalhães d.s.," thermodynamic properties of moisture desorption isotherms of ryegrass (lolium multiflorum l.) seeds, ciência e agrotecnologia, 44:e027619, 2020. [27] hawa l. c., lastriyanto a., tambunan t. n. ," sorption characteristics of banana slices (musa paradisiaca l.) var. raja nangka by gravity method", advances in food science, sustainable agriculture and agroindustrial engineering,vol.1 ,no.1,pp. 19 – 24,2018. [28] oluwamukomi m. o. , "adsorption isotherm modeling of soy-melon-enriched and un-enriched ‘gari’ using gab equation", african journal of food science, vol. 3no.5, pp. 117-124, may, 2009. [29] alakali j., irtwange s.v. and satimehin a. ,"moisture adsorption characteristics of ginger slices",cienc tecnol. aliment.,vol.29,no.1, 2009. [30] blahovec j. & yanniotis s.," gab generalized equation for sorption phenomena", food bioprocess technol. , vol.1,pp.82–90,2008. [31] gustavo v. b., anthony j. f., schmidt j.s. , labuza t.p.," water activity in foods: fundamentals and applications, second edition, john wiley & sons, inc,2020. [32] arogba s.s.," effect of temperature on the moisture sorption isotherm of a biscuit containing mango kernel flour", journal of food engineering ,vol.,no.48 pp.121-125,2001. [33] zammouri, a. , ben z. m. , kechaou, n. , mihoubi b., "thermodynamic properties and moisture sorption isotherms of two pharmaceutical compounds ", 21st international drying symposium, spain, 11-14 september, conference paper, 2018. [34] parmar j. & rane m. ,"tablet formulation design and manufacture: oral immediate release application", pharma times, vol. 41 , no. 4 , april ,2009. http://www.tainstruments.com/pdf/literature/ta329a%20moisture%20sorption%20analysis%20of%20pharmaceuticals.pdf http://www.tainstruments.com/pdf/literature/ta329a%20moisture%20sorption%20analysis%20of%20pharmaceuticals.pdf https://www.mdpi.com/1996-1073/13/10/2544 https://www.mdpi.com/1996-1073/13/10/2544 https://www.mdpi.com/1996-1073/13/10/2544 https://www.mdpi.com/1996-1073/13/10/2544 https://www.mdpi.com/1996-1073/13/10/2544 https://hrcak.srce.hr/225634 https://hrcak.srce.hr/225634 https://hrcak.srce.hr/225634 https://hrcak.srce.hr/225634 https://hrcak.srce.hr/225634 https://www.scielo.br/scielo.php?pid=s1806-66902020000100401&script=sci_arttext https://www.scielo.br/scielo.php?pid=s1806-66902020000100401&script=sci_arttext https://www.scielo.br/scielo.php?pid=s1806-66902020000100401&script=sci_arttext https://www.scielo.br/scielo.php?pid=s1806-66902020000100401&script=sci_arttext https://www.scielo.br/scielo.php?pid=s1806-66902020000100401&script=sci_arttext https://www.sciencedirect.com/science/article/abs/pii/s0963996920300582 https://www.sciencedirect.com/science/article/abs/pii/s0963996920300582 https://www.sciencedirect.com/science/article/abs/pii/s0963996920300582 https://www.sciencedirect.com/science/article/abs/pii/s0963996920300582 https://www.sciencedirect.com/science/article/abs/pii/s0963996920300582 https://iopscience.iop.org/article/10.1088/1757-899x/595/1/012058/meta https://iopscience.iop.org/article/10.1088/1757-899x/595/1/012058/meta https://iopscience.iop.org/article/10.1088/1757-899x/595/1/012058/meta https://nvlpubs.nist.gov/nistpubs/jres/81a/jresv81an1p89_a1b.pdf https://nvlpubs.nist.gov/nistpubs/jres/81a/jresv81an1p89_a1b.pdf https://nvlpubs.nist.gov/nistpubs/jres/81a/jresv81an1p89_a1b.pdf https://nvlpubs.nist.gov/nistpubs/jres/81a/jresv81an1p89_a1b.pdf https://www.scielo.br/scielo.php?pid=s1413-70542020000100202&script=sci_abstract&tlng=pt https://www.scielo.br/scielo.php?pid=s1413-70542020000100202&script=sci_abstract&tlng=pt https://www.scielo.br/scielo.php?pid=s1413-70542020000100202&script=sci_abstract&tlng=pt https://www.scielo.br/scielo.php?pid=s1413-70542020000100202&script=sci_abstract&tlng=pt https://www.scielo.br/scielo.php?pid=s1413-70542020000100202&script=sci_abstract&tlng=pt https://afssaae.ub.ac.id/index.php/afssaae/article/view/4 https://afssaae.ub.ac.id/index.php/afssaae/article/view/4 https://afssaae.ub.ac.id/index.php/afssaae/article/view/4 https://afssaae.ub.ac.id/index.php/afssaae/article/view/4 https://afssaae.ub.ac.id/index.php/afssaae/article/view/4 https://afssaae.ub.ac.id/index.php/afssaae/article/view/4 https://academicjournals.org/journal/ajfs/article-abstract/c51ff2120266 https://academicjournals.org/journal/ajfs/article-abstract/c51ff2120266 https://academicjournals.org/journal/ajfs/article-abstract/c51ff2120266 https://academicjournals.org/journal/ajfs/article-abstract/c51ff2120266 https://www.scielo.br/scielo.php?pid=s0101-20612009000100024&script=sci_arttext https://www.scielo.br/scielo.php?pid=s0101-20612009000100024&script=sci_arttext https://www.scielo.br/scielo.php?pid=s0101-20612009000100024&script=sci_arttext https://link.springer.com/article/10.1007%2fs11947-007-0012-3 https://link.springer.com/article/10.1007%2fs11947-007-0012-3 https://link.springer.com/article/10.1007%2fs11947-007-0012-3 https://books.google.iq/books?hl=en&lr=&id=wivgdwaaqbaj&oi=fnd&pg=pr5&dq=water+activity+in+foods:+fundamentals+and+applications&ots=deo8x-bqlx&sig=qnohrq3w2wzowgc-i6glejmvzso&redir_esc=y#v=onepage&q=water%20activity%20in%20foods%3a%20fundamentals%20and%20applications&f=false https://books.google.iq/books?hl=en&lr=&id=wivgdwaaqbaj&oi=fnd&pg=pr5&dq=water+activity+in+foods:+fundamentals+and+applications&ots=deo8x-bqlx&sig=qnohrq3w2wzowgc-i6glejmvzso&redir_esc=y#v=onepage&q=water%20activity%20in%20foods%3a%20fundamentals%20and%20applications&f=false https://books.google.iq/books?hl=en&lr=&id=wivgdwaaqbaj&oi=fnd&pg=pr5&dq=water+activity+in+foods:+fundamentals+and+applications&ots=deo8x-bqlx&sig=qnohrq3w2wzowgc-i6glejmvzso&redir_esc=y#v=onepage&q=water%20activity%20in%20foods%3a%20fundamentals%20and%20applications&f=false https://books.google.iq/books?hl=en&lr=&id=wivgdwaaqbaj&oi=fnd&pg=pr5&dq=water+activity+in+foods:+fundamentals+and+applications&ots=deo8x-bqlx&sig=qnohrq3w2wzowgc-i6glejmvzso&redir_esc=y#v=onepage&q=water%20activity%20in%20foods%3a%20fundamentals%20and%20applications&f=false https://www.sciencedirect.com/science/article/abs/pii/s0260877400001448 https://www.sciencedirect.com/science/article/abs/pii/s0260877400001448 https://www.sciencedirect.com/science/article/abs/pii/s0260877400001448 https://www.sciencedirect.com/science/article/abs/pii/s0260877400001448 https://riunet.upv.es/handle/10251/117937 https://riunet.upv.es/handle/10251/117937 https://riunet.upv.es/handle/10251/117937 https://riunet.upv.es/handle/10251/117937 https://riunet.upv.es/handle/10251/117937 m. m. a. alhussaini et al. / iraqi journal of chemical and petroleum engineering 21,4 (2020) 11 20 20 دراسة عملية أليزوثيرم امتزاز الرطوبة ألقراص ميفانميك أسيد 2 , ندى سعدون أحمدزكي1, حسنين عباس حسن 1مها محي الحسيني قسم الهندسة الكيمياوية \كلية الهندسة\جامعة بغداد 1 قسم الهندسة الكيمياوية والصناعات النفطية \كلية المستقبل الجامعة 2 الخالصة تعتبر دراسة االيزوثيرم من الطرق التقليدية لوصف العالقة مابين محتوى الرطوبة عند االتزان والرطوبة النسبية بثبوت درجة الحرارة والضغط. تم قياس محتوى الرطوبة باستعمال طريقة المحاليل الملحية المشبعة عند %(. النتائج 0,8434 0,065يتراوح بين) درجة مئوية و محتوى رطوبة45و 35,25ثالث درجات حرارية اوضحت ان محتوى الرطوبة عند االتزان يزداد مع زيادة الرطوبة النسبية بثبوت درجة الحرارة ويقل مع زيادة درجة الحرارة بثبوت الرطوبة النسبية اي ان استقرارية المادة ازدادت.من المنحنيات اتضح ان المادة من النوع ف برونير وان ظاهرة الهسترة واضحة عند الدرجات الحرارية الثالث.تم مطابقة النتائج العملية الثاني حسب تصني بور. وكان االخير هو االفضل -اندرسون و دي -مع ثالث موديالت رياضية هي سميث, اوسون و كوكنهام م حساب محتوى في وصف االيزوثيرم القراص ميفانميك اسيد . لتحديد محتوى الرطوبة عند خزن المنتج ,ت الرطوبة للطبقة الواحدة باستعمال الموديل واتضح انه يجب ان تخزن عند او أعلى قليال من: لالمتزاز %(. 0,1452, 2073,0,1269%( انتزاز),0,1843,0,143, 0,2046) اقراص ميفانميك اسيد.الكلمات الدالة: ايزوثيرم ,االمتزاز, محتوى الرطوبة عند االتزان,الرطوبة النسبية, نمذجة رياضية, available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol. 24 no.2 (june 2023) 11 – 18 eissn: 2618-0707, pissn: 1997-4884 *corresponding author: name: ekhlas a. salman, email: ekhlas.a.salman@nahrainuniv.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. effect of black carbon and alumina nanofluid on thermal and dynamic efficiency in upward spraying cooling tower ekhlas a. salman a, b, *, hasan f. makki b, and adel sharif c a chemical engineering department, college of engineering, al-nahrain university, baghdad, iraq b chemical engineering department, college of engineering, university of baghdad, baghdad, iraq c department of chemical and process engineering, university of surrey, surrey, uk abstract in cooling water systems, cooling towers play a critical role in removing heat from the water. cooling water systems are commonly used in industry to dispose the waste heat. an upward spray cooling water systems was especially designed and investigated in this work. the effect of two nanofluids (al2o3/ water, black carbon /water) on velocity and temperature distributions along reverse spray cooling tower at various concentrations (0.02, 0.08, 0.1, 0.15, and 0.2 wt.%) were investigated, beside the effect of the inlet water temperature (35 ,40, and 45 ͦ c) and water to air flow ratio (l/g) of 0.5, 0.75, and 1. the best thermal performance was found when the working solution contained 0.1 wt.% for each of al2o3 and black carbon nanoparticles, with a maximum drop in temperature drops (i, e. range) of (16 ͦ c) and (20 ͦ c), respectively. the temperature of the tower's outlet water was decreased as the inlet working fluid increased, and the thermal efficiency declined with the increasing of the l/g by about 5%. however, the drop in the outlet temperature caused by the nanofluid is more than that of pure water at every point by about 6 ͦ c. keywords: cooling tower, nanofluid black carbon, thermal efficiency. received on 08/10/2022, received in revised form on 30/11/2022, accepted on 01/12/2022, published on 30/06/2023 https://doi.org/10.31699/ijcpe.2023.2.2 1introduction reducing water temperature is accomplished through the employment of a device that removes heat from the water and releases it into the atmosphere. power generation and refrigeration are only a few examples of their many applications. in industrial facilities, cooling towers are designed in many types and sizes in order to produce cold water. water is typically used to cool a condenser in a power plant [1, 2]. "nanofluids" are industrial fluids with solid particles smaller than a nanometer. it has been demonstrated that the heat transfer characteristics of base fluids may be significantly improved by nanoparticles. it lessens the pressure drop and sedimentation issues that bigger particles and microparticles often experience [3]. the heat from hot water is dissipated by direct contact with cool and dry air in cooling towers. direct contact cooling is used by the majority of plants, whereas indirect contact cooling is used by a minority [4]. it has been discovered that adding nano-sized (100 nm) solid nanoparticles to base fluids results in nanofluids, which boost thermal performance in heat transfer systems by increasing thermal conductivity. the properties of both the nanoparticles and the base fluid alter their transport and thermal characteristics, making nanofluid a colloidal mixture. any settling motion brought on by gravity is resisted by brownian agitation, which is the essential characteristic of nanofluids. a stable nanofluid should be achievable as long as the particles remain small (usually about 100 nm) [5]. however, nanofluids are produced by stabilizing and suspending nanometer-size particle in standard heat transfer fluids (ethanol, water, etc.) nanofluids, including multi-wall graphene and carbon nanotube, increased heat transmission when used to replace nano fluorocarbon in an experiment cooling towers [6]. additionally, utilizing a unique method of balancing ambient factors, the impact of various nanofluids on the thermal effectiveness of a wet cooling towers was explored [7]. the mixes of alumina/water, silica/water, zinc oxide/water, and graphene/water were all studied in a wet cooling tower with crossflow. based on their results, the fluid of the graphene/water produced maximum efficiency and increased the tower's characteristics efficiency [8, 9]. the type of the cooling tower plays an essential rule in the performance, and the especially the direction of movement of the two fluids [10]. the type of the fills or the direction of flow is very effective on the cooling range [11]. the spray cooling tower is one of the used towers in which the water and the air is in direct counter current contact [12]. the effect of working fluid type on reverse spray cooling tower performance and the problems of operation has only been the subject of so few researches [13, 14]. also, the shape of the tower plays a crucial rule in the http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:ekhlas.a.salman@nahrainuniv.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2023.2.2 e. a. salman et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 11 18 12 performance [15]. as a result of the cooling tower's importance and applicability in various industries, as well as the particular properties of nanofluids, additional research on this type of reverse spray cooling tower is required. in this study the performance of reverse upward spray cooling tower especially designed will be investigated to examine the usage of two type of nanofluid at various concentration (which are (al2o3/ water, black carbon /water)) (0.02, 0.08, 0.1, 0.15, and 0.2 wt.%) on velocity and temperature distributions along the height of the tower at different inlet temperature of the nanofluid (35,40, and45 ͦ c) and different water to air flow ratio l/g (0.5, 0.75, and 1). 2experimental work 2.1. reverse spray cooling tower a schematic diagram of the reverse spray cooling tower specifically designed and used in our experiments are shown in fig. 1. the length is (2 m) and have a diameter of (0.7 m). air is drawn into the cooling tower through a fan, where it passes through two holes, the diameter of the hole is 20 cm. at the point of entry, it passes through a channel of silica gel made of acrylic material, which is placed on a perforated plate to give constant air humidity during the operation process [14, 16]. functional segment, a number of nozzles are placed and coordinated vertically at the bottom of the tower, so that when the water is in the ascendant motion it will flow co-currently with the air, but when it in the descendant movement it will flow counter-currently with the up-word air. large water droplets in the air stream of a cooling tower can be collected using a section called a “drift eliminator.” the eliminators keep the mist and water droplets inside the cooling tower [17]. 2.2. air system two layers of silica gel are sandwiched between two punctured acrylic plate screens to maintain a constant level of humidity in the operating area of the tower from the outside air. the air is supplied by a variable-speed fan. for the cooling tower's incoming and output air, temperature and humidity sensors are used. 2.3. water system as depicted in fig. 1, this experiment utilized a water supply system. pump, high-pressure piping, and spray nozzle are all included in the system's construction. there is only one water tank in the entire setup. pumping water from the main tank to the spray nozzles will use a variable speed, a high-pressure water pump that can produce up to 8 l/min of flow throughout the experiment. the flow rate to the spray nozzle is controlled by a bypass valve, with excess water being routed to the auxiliary water tank upstream of the nozzle. 2.4. spray nozzle system in the studies, various spray nozzles were used. the choice of nozzle is a critical part of the experiment. when selecting a spray nozzle, the following are the most important considerations: size distribution, flow velocity, and spray cone angle are all things to keep in mind while deciding on a droplet size distribution [18]. the spray cooling tower's thermal performance dictates the droplet size, liquid flow rate, and spray angle. this experiment used hollow cone nozzles only. humidification systems frequently employ this design. for adequate saturation of the inlet air, spray nozzles with the highest water flow rate, lowest droplet size dispersion, and widest spray cone angles were selected. fig. 1. schematic diagram of experimented cooling tower e. a. salman et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 11 18 13 2.5. preparation of the nanofluids compared to other nanoscale items, alumina nanoparticles are highly stable and can be easily distributed in water to generate colloidal nanofluids. in this study, and based on the required weight concentration of the nanofluid, a precise amount of al2o3 and black carbon nanoparticles manufactured by “ireej al-fourt co.” were chosen for the spray cooling investigation and their specification are illustrated in table 1. the nano fluid solution had been prepared by adding the specific weight of the nanoparticles to pure water inside and ultrasonic bath (working frequency: 28 khz) for 1.5 hr, this had been done to obtain suspended particles in stable situation. gum arabic (ga) had been added also to improve the stability of the suspension of the nano particles in water. it had been noted at the end of each run that there is no participation which guarantee the stability of the nanofluid. table 1. general characteristics of the al2o3 and black carbon nanoparticles utilized in the research nanoparticle aluminum oxide black carbon average diameter (nm) 20-40 10-20 chemistry formula al2o3 c special area (m2 /g) 90-220 90–160 color white black morphology sphere spherical purity > 99.99% 99.7% density (g/cm3) 3.65 0.07-0.32 3results and discussions fig. 2 to fig. 10, show the effects of various water/al2o3 nanofluid concentrations (0.05, 0.08, 0.1, 0.15, 0.2 wt. %) on the droplet velocities and temperatures distributions along the tower for various inlet working fluid temperatures (35,40, and45 ͦ c). more specifically, fig. 2, draws attention to the droplet velocities of the water and nanofluid, when the nano concentration is 0.05 wt. %, there is no noticeable difference, especially in the descent stage (except 0.05). the spray with the highest droplet velocity is water, whereas the spray with the lowest droplet velocity is 0.1wt.% nanofluid. the droplet velocities of the remaining mass concentrations (0.08, 0.05, 0.15 and 0.2 wt%) of the nanofluids are intermediate, and there are no significant differences between them. at an inlet working temperature of 35°c, fig. 3, shows that the temperature drops increase as the nanofluid concentration increases. the water solutions with nano al2o3 of 0.05, 0.08, 0.1, 0.15, and 0.2 wt% concentrations, their outlet temperatures had been decreased to 24.8, 24.4, 24, 23.5, 24.5, and 24.6 °c, respectively. as shown in this figure, increasing nanofluid concentration increases energy absorption and release it to the air. this behavior is also confirmed by another study [7, 19]. three mechanisms were accomplished, convective mass transfer, heat transfer, and convective heat transfer. therefore, increasing the nanofluid concentration increases heat transmission through conduction and convection. also, the increase in the concentration of the nano particles in the water will increase the solution viscosity, and this will slow down the motion of the solution which will lead to increase the contact time between the two fluids, but after a certain concentration, this decrease in the velocity will have a negative effect on the heat transfer. fig. 3, illustrates that the outlet working fluid has increased to greater than 0.1 wt% as concentration has increased. the primary challenge associated with applying nanofluids is the aggregation of particles, which can reduce their heat transmission capabilities. the probability of agglomeration increases as the nanofluid concentration rises. the cooling range decrease may be due to this phenomenon. although with the reduced range. utilizing pure water and 0.1 wt% al2o3/water nanofluid at inlet operating fluid temp of 35, 40, and 45°c, the impacts of inlet operating fluid temp on exit operating fluid temperature were examined. fig. 3, fig. 5, and fig. 7 display the impact of nanofluid (al2o3/water) on droplet temperature distribution at an inlet water temperature of 35°c. the nanofluid exit temperature is lowest than that of pure water. alternatively, the cooling tower rejects more heat when a nanofluid is utilized. fig. 2. effect of nanofluid (al2o3/ water) concentration on droplet velocity distribution at inlet water temperature 35 ͦ c fig. 3. effect of nanofluid (al2o3/ water) on droplet temperature distribution at inlet water temperature 35 ͦ c in addition, when the working fluid’s inlet temperature is increased, the nanofluid’s temperature decrease is significantly more significant than that of water. for instance, for discharge droplet velocity of 8 m/s with inlet operating fluid temps of 35, 40, and 45c, the output operating fluid temperatures for pure water and nanofluid, respectively, are 24.8, 28.6, and 31 °c. these figures also e. a. salman et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 11 18 14 show that the cooling range is improved by raising the working fluid’s inlet temperature. in particular, the cooling range increases as the nanofluid’s inlet temperature increases, while the working fluid’s output temp essentially remains unchanged. the cooling range was expanded by 2.21 °c for water and by 2.80 °c for nanofluid by rising the operating fluid inlet temperature 40 45c. fig. 4. effect of nanofluid (al2o3 /water) concentration on droplet velocity distribution at inlet water temperature 40 ͦ c fig. 5. the effect of nanofluid (al2o3 /water) concentration on droplet temperature distribution at inlet water temperature 40 ͦ c fig. 6. effect of nanofluid (al2o3/ water) concentration on droplet velocity distribution at inlet water temperature 45 ͦ c fig. 8 to fig. 13, show the effects of various black carbon/ water nanofluid concentrations (0.05, 0.08, and 0.1,0.15, and 0.2 wt. %) on droplet velocity and temperature distributions along tower height for various inlet working fluid temperatures (35, 40, and 45 ͦ c). fig. 7. effect of nanofluid (al2o3/ water) concentration on droplet temperatures distribution at inlet water temperature 45 ͦ c fig. 8 displays the droplet velocities of water and nanofluid (blackcarbon/water) concentration. there were no apparent variations, particularly in the spray downstream of blackcarbon/ water. droplet velocity was lowest in black carbon with 0.05 wt%, then by 0.08 wt% and 0.1wt%. these results showed that higher concentration nanofluids formed droplets with lower droplet velocity. this means that the effect of black carbon/ water concentration on discharge droplet velocity is not significantly different from that of al2o3 /water. regarding these results, as the temperature of the entering water increases, the temperature drops increases, particularly at (45 ͦ c). it is generally known that water would be cooled to the wet-bulb temperature before entering the air for optimal cooling tower operation. when using nanofluids in a cooling tower, the cooling range is more significant than when using water. this is because the presence of carbon nanoparticles enhances the base fluid’s properties for heat transfer. by improving thermal conductivity, the convection heat transfer coefficient, and surface area, nanofluids improve heat transfer between air and liquid flows. the temperature differences increase from 10.2 ͦ c, 11.4 ͦ c, and 14 c for water to 12 ͦ c, 13 c, and 19.4 c for black carbon nanofluid at 35, 40, and 45c. fig. 8. effect of nanofluid (black carbon/ water) concentration on droplet velocity distribution at inlet water temperature 35 ͦ c e. a. salman et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 11 18 15 fig. 9. effect of nanofluid (black carbon/water) on droplet temperature distribution at inlet water temperature 35 ͦ c fig. 10. effect of nanofluid (black carbon/ water) concentration on droplet velocity distribution at inlet water temperature 40 ͦ c fig. 11. effect of nanofluid (black carbon/ water) concentration on droplet temperature distribution at inlet water temperature 40 ͦ c fig. 12. effect of nanofluid (black carbon/ water) concentration on droplet velocity distribution at inlet water temperature 45 ͦ c fig. 13. effect of nanofluid (black carbon/ water) concentration on droplet temperature distribution at inlet water temperature 45 ͦ c the finding in fig. 14 demonstrates that the cooling tower thermal efficiency is influenced by the mass flow ratios of the flowing fluid/air (l/g). raising the ratio often results in a decline in the cooling tower’s thermal effectiveness and water temp drop, and this is in agree with other studies [4, 11]. the tower’s efficiency decreased from 46% to 41% when using al2o3/water nanofluid at 45 °c with an l/g ratio of 0.5-1, also for thermal efficiency for black carbon as shown in fig. 15. the use of nanofluids enhances the cooling tower’s effectiveness. when nanoparticles are dispersed in water, the surface area available for heat transfer increases, the thermal conductivity rises which will improve heat transfer. also, the increase in the nano concentration to a certain limit will increase the solution viscosity, and this will slow down the motion of the solution which will lead to increase the contact time between the two fluids and this will also be decreasing the temperature difference between fluid layers. consequently, the cooling tower conditions improve, and the heat transfer is enhanced. greater efficiency may be attained at lower l/g and higher inlet water temperatures because nanofluids have better available thermal characteristics, these results are in agreement with another study [11, 19]. fig. 14. effects of discharge droplet velocity (8m/s) at (45 ͦ c) on efficiency of various al2o3/water to mass flow rate of air e. a. salman et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 11 18 16 fig. 15. effects of discharge droplet velocity (8m/s) at (45 ͦ c) on nanofluid (black carbon/water) droplet temperature and efficiency for different (l/g) ratios 4conclusions effect of two nanofluids (al2o3/ water, black carbon /water) on velocity and temperature distributions through the height of reverse spray cooling tower at various concentrations (0.02, 0.08, 0.1, 0.15, and 0.2 wt.%) had been investigated for different inlet solution temperature. the best thermal performance is seen in the solution that contains 0.1 wt.% of both al2o3 or black carbon, with temperature drops of about (16 ͦ c) and (20 ͦ c) from the inlet temperature of the water, respectively. the use of nanofluids has greatly increased the cooling tower thermal performance. this performance improvement changes according to the nanoparticle type (both black carbon and al2o3), nanofluid concentration, inlet working fluid temperature (35,40,45 ͦ c), and working fluid mass flow ratio to air. for example, at 45 °c, utilizing black carbon /water nanofluid (0.1 wt%) increases efficiency by 44.3% to 63.2% over pure water in the same temperature and circumstances. the effect of using nano carbon was more pronounced in comparison to al2o3 the temperature of the tower's outlet water decreases as the inlet working fluid increases and the thermal efficiency declines with the increase in the l/g. however, the drop in the outlet temperature caused by the nanofluid is more than that of pure water. references [1] xia, l., gurgenci, h., liu, d., guan, z., zhou, l., and wang, p. (2016). cfd analysis of pre-cooling water spray system in natural draft dry cooling towers. applied thermal engineering, 105, 10511060. https://doi.org/10.1016/j.applthermaleng.2016.03.096 [2] xiao, l., ge, z., yang, l., and du, x. (2018). numerical study on performance improvement of aircooled condenser by water spray cooling. international journal of heat and mass transfer, 125, 1028-1042. https://doi.org/10.1016/j.ijheatmasstransfer.2018.05.0 06 [3] bianco, v., manca, o., and nardini, s. (2014a). performance analysis of turbulent convection heat transfer of al2o3 water-nanofluid in circular tubes at constant wall temperature. energy, 77(1), 403-413. https://doi.org/10.1016/j.energy.2014.09.025 [4] shaymaa a. ahmed, forat yasir aljaberi , hasan f. makki. (2022). experimental investigation of the thermal performance of wet cooling tower with splash fills packing. thermal science, vol. 26, (2) part b, 1603-1613, https://doi.org/10.2298/tsci210621004a [5] amini, m., zareh, m., and maleki, s. (2020). thermal performance analysis of mechanical draft cooling tower filled with rotational splash type packing by using nanofluids. applied thermal engineering, 175, 115268. https://doi.org/10.1016/j.applthermaleng.2020.11526 8 [6] askari, s., lotfi, r., seifkordi, a., rashidi, a. m., and koolivand, h. (2016). a novel approach for energy and water conservation in wet cooling towers by using mwnts and nanoporous graphene nanofluids. energy conversion and management, 109, 10-18. https://doi.org/10.1016/j.enconman.2015.11.053 [7] yajima, s., and givoni, b. (1997). experimental performance of the shower cooling tower in japan. renewable energy, 10(2), 179-183. https://doi.org/10.1016/0960-1481(96)00060-2 [8] zaichik, l. i., and pershukov, v. a. (1990). influence of particles on the initial stage of homogeneous turbulence degeneration. journal of engineering physics, 58(4), 408-412. https://doi.org/10.1007/bf00877345 [9] yang, l. j., chen, l., du, x. z., and yang, y. p. (2013). effects of ambient winds on the thermo-flow performances of indirect dry cooling system in a power plant. international journal of thermal sciences, 64, 178-187. https://doi.org/10.1016/j.ijthermalsci.2012.08.010 [10] shaymaa a. ahmed. zinc element traces to inhibit scale formation on cooling tower and air cooler systems. (2013). iraqi journal of chemical and petroleum engineering. vol.14 no.2 4148. [11] yang, l. j., wu, x. p., du, x. z., and yang, y. p. (2013). dimensional characteristics of wind effects on the performance of indirect dry cooling system with vertically arranged heat exchanger bundles. international journal of heat and mass transfer, 67, 853-866. https://doi.org/10.1016/j.ijheatmasstransfer.2013.08.0 85 [12] s. yaro, a., a.k.rasheed, h., & a.k. rasheed, h. (2008). cathodic protection of copper pipes carrying saline water in the presence of aerobic bacteria. iraqi journal of chemical and petroleum engineering, 9(4), 35–40. https://doi.org/10.31699/ijcpe.2008.4.6 https://doi.org/10.1016/j.applthermaleng.2016.03.096 https://doi.org/10.1016/j.ijheatmasstransfer.2018.05.006 https://doi.org/10.1016/j.ijheatmasstransfer.2018.05.006 https://doi.org/10.1016/j.energy.2014.09.025 https://doi.org/10.2298/tsci210621004a https://doi.org/10.1016/j.applthermaleng.2020.115268 https://doi.org/10.1016/j.applthermaleng.2020.115268 https://doi.org/10.1016/j.enconman.2015.11.053 https://doi.org/10.1016/0960-1481(96)00060-2 https://doi.org/10.1007/bf00877345 https://doi.org/10.1016/j.ijthermalsci.2012.08.010 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/312 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/312 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/312 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/312 https://doi.org/10.1016/j.ijheatmasstransfer.2013.08.085 https://doi.org/10.1016/j.ijheatmasstransfer.2013.08.085 https://doi.org/10.31699/ijcpe.2008.4.6 e. a. salman et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 11 18 17 [13] zou, z., guan, z., and gurgenci, h. (2013). optimization design of solar enhanced natural draft dry cooling tower. energy conversion and management, 76, 945-955. https://doi.org/10.1016/j.enconman.2013.08.053 [14] zheng, w.-y., zhu, d.-s., zhou, g.-y., wu, j.-f., and shi, y.-y. (2012). thermal performance analysis of closed wet cooling towers under both unsaturated and supersaturated conditions. international journal of heat and mass transfer, 55(25), 7803-7811. https://doi.org/10.1016/j.ijheatmasstransfer.2012.08.0 06 [15] ahmed, s. a.-r. and makki, h. f. (2019) “corrosion rate optimization of mild-steel under different cooling tower working parameters using taguchi design”, journal of engineering, 26(1), pp. 174–185. https://doi.org/10.31026/j.eng.2020.01.13 [16] zhao, y., sun, f., li, y., long, g., and yang, z. (2015). numerical study on the cooling performance of natural draft dry cooling tower with vertical delta radiators under constant heat load. applied energy, 149, 225-237. https://doi.org/10.1016/j.apenergy.2015.03.119 [17] a.s. yaroو a.a. khadom, m. a. idan, electrochemical approaches of evaluating galvanic corrosion kinetics of copper alloy – steel alloy couple in inhibited cooling water system , j. mater. environ. sci. 6 (4) (2015) 1101-1104. [18] zhao, y. b., long, g., sun, f., li, y., and zhang, c. (2015). numerical study on the cooling performance of dry cooling tower with vertical two-pass column radiators under crosswind. applied thermal engineering, 75, 1106-1117. https://doi.org/10.1016/j.applthermaleng.2014.10.061 [19] zhu, h.-h., wang, k., and he, y.-l. (2017). thermodynamic analysis and comparison for different direct-heated supercritical co2 brayton cycles integrated into a solar thermal power tower system. energy, 140, 144-157. https://doi.org/10.1016/j.energy.2017.08.067 [20] shaymaa a. ahmed and hasan f. makki.(2020). corrosion behavior of mild-steel in cooling towers using high salinity solution. aip conference proceedings 2213, 020178; https://doi.org/10.1063/5.0000274 https://doi.org/10.1016/j.enconman.2013.08.053 https://doi.org/10.1016/j.ijheatmasstransfer.2012.08.006 https://doi.org/10.1016/j.ijheatmasstransfer.2012.08.006 https://doi.org/10.31026/j.eng.2020.01.13 https://doi.org/10.1016/j.apenergy.2015.03.119 https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=1174417f8b14de19a08a3cd723a4d49cbe367779 https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=1174417f8b14de19a08a3cd723a4d49cbe367779 https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=1174417f8b14de19a08a3cd723a4d49cbe367779 https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=1174417f8b14de19a08a3cd723a4d49cbe367779 https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=1174417f8b14de19a08a3cd723a4d49cbe367779 https://doi.org/10.1016/j.applthermaleng.2014.10.061 https://doi.org/10.1016/j.energy.2017.08.067 https://doi.org/10.1063/5.0000274 e. a. salman et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 11 18 18 في برج ناميكيةالكربون األسود واأللومينا( على الكفاءة الحرارية والديالنانو فلود ) تأثير التبريد باستخدام الرش باالعلى 3و عادل شريف ، 2 مكي حسن فرهود ،، *2، 1 اخالص عبدالرحمن العراق ،بغداد النهرين،جامعة ،كلية الهندسة ،قسم الهندسة الكيمياوية 1 العراق ،بغداد بغداد،جامعة ،كلية الهندسة ،قسم الهندسة الكيمياوية 2 قسم هندسة العمليات والهندسة الكيمياوية، جامعة سري، سري، المملكة المتحدة 3 الخالصة ريد م برج التبتبريد المياه, برج التبريد يلعب دور مهم في العملية لتبديد الحرارة من المياه. يستخدفي انظمة . تم ىلتبريد من نوع الرذاذ نحو االعلبكثرة في العمليات الصناعية. تم تصميم ودراسة نوع خاص من ابراج ا , 0,08, 0.02و الكاربون( و بتراكيز مختلفة )دراسة تاثير تركيز المواد النانوية من نوعين ) اوكسيد االلمنيوم باالضافة الى ،( علي توزيع السرعة و الحرارة على طول البرج الرذاذ نحو االعلى% 0,2, و 0,15, 0,1 ائل الى درجة مئوية( ونسبة جريان الس 45, و 40, 35دراسة تاثيركل من درجة حرارة المحلول النانوي الداخل ) ي (. لقد وجد ان افضل كفاءة حرارية تم الحصول عليها عندما كان المحلول يحتو 1و ,0,75, 0,5الهواء ) لى الكن من اوكسيد االلمنيوم او الكاربون حيث وصل اعلى هبوط لدرجة الحرارة %0,1مواد نانوية بتركيز ع لمائادرجة حراة درجة مئوية على الترتيب. درجة حرارة المحلول النانوي الخارج تقل ايضا مع زيادة 20و 16 فأن عموما ،%5( حوالي l/gبينما الكفاءة الحرارية تقل مع زيادة نسبة جريان السائل الى الهواء ) ،الداخل عند درجات 6الهبوط في درجة الحرارة ب استخدام مواد نانوية كان اكثر من استخدام الماء الصافي ب حوالي كل نقطة من نقاط البرج. ابراج التبريد، نانو الكاربون االسود، الكفاءة الحرارية البراج التبريد. الكلمات الدالة: 43 vol.12 no.1 (march 2011) iraqi journal of chemical and petroleum engineering vol.12 no.1 (march 2011) 43 52 issn: 1997-4884 reuse of domestic wastewater for irrigation: conceptual and basic design elements abdul-fattah mohamed ali environmental eng.dept., college of eng., baghdad university abstract in iraq, water shortages and drought, especially during the hot summer months, necessitates that municipal authorities adopt water reuse projects like reusing treated domestic wastewater for crop irrigation. this work gives the conceptual and basic design elements for the necessary steps of filtration, uv irradiation and chlorination to make such a wastewater fit for agricultural use. a typical rural community of 50,000 people is considered as an example case for which functionality and relative simplicity of the proposed designs are prime factors. the objectives are 1) to show what is required and 2) that the presented information may be utilized to embark on the following phases of detailed design and execution of such projects. keywords: wastewater reuse; crop irrigation; wastewater filtration; uv irradiation of wastewater ; wastewater chlorination. introduction historically, iraq enjoyed an abundance of fresh surface water resources (euphrates, tigris rivers and their tributaries). however, in recent decades this situation has changed dramatically and irreversibly due to water impoundment projects in river-source neighboring countries and erratic rainfall probably caused by climate change. consequently, the country now faces water shortages especially during the hot summer months of june, july and august. additionally, many rural communities have been provided with potable water supply units but lack domestic wastewater treatment facilities creating an ongoing potential environmental problem. it is, therefore, highly relevant that such planned facilities should incorporate means to render treated domestic wastewater suitable for irrigation. iraqi journal of chemical and petroleum engineering university of baghdad college of engineering reuse of domestic wastewater for irrigation: conceptual and basic design elements 44 vol.12 no.1 (march 2011) this work provides the conceptual and basic design elements necessary to embark on the detailed design and execution phases for the achievement of the aforementioned goal. a rural community of 50,000 people with an assumed domestic wastewater flow rate of 12,600 m 3 /d is considered as an example case for illustration purposes. the presented design elements include sufficient margins to ensure functionality and could serve as a general guideline for other capacities. they are based on information available in the literature and author's experience in water/wastewater treatment. pre-requisites it is assumed that a conventional medium-rate activated sludge process (0.2 < f m < 0.5 d -1 ) is adopted for the domestic wastewater treatment facility resulting in a standard secondary effluent (bod5 ≅ 25, s.s ≅ 35, fog ≅ 10, all mg/l) which is 10 to 20 % nitrified (vernick and walker [1]). for the community size under consideration, this process should include a properly sized equalization basin to dampen out diurnal and seasonal wastewater flow and concentration variations. treatment requirements the secondary effluent with the said specifications requires the following to make it suitable for crop irrigation (abdulraheem [2]; el-wakeel et al. [3]) the count of pathogenic microorganisms in the ww must be reduced to the level commensurate with this reuse category. additionally, a means of maintaining the ww quality should be provided to ensure its suitability until it reaches the agricultural fields. reduction of pathogenic microorganisms count is achieved by disinfection, the extent of which is based on indicator microorganisms; namely faecal/total coliforms. however, the efficacy of disinfection is negatively affected by the s.s/turbidity of the ww (due to its masking effect shielding some microorganisms from disinfection [4]). therefore, proper filtration of the ww is a necessary preliminary stage whenever disinfection is o be carried out. following filtration and disinfection, maintenance of the ww quality until it is used is related to the type of disinfection process chosen as will be made clear in due course. filtration the adopted design approach for this operation is based on the assumption that it should be similar to that used in potable water supply units, since considerable design and operational experience exist in this respect in municipalities all over the country. filtration system general specifications (metcalf and eddy [5]; abdul-fattah [9]; crites and tchobanoglous [10]; degremont [11]; tebbutt [13]) type: rapid gravity flow, deep-bed, mono-medium filter. medium : sand with an effective size of 2 to 3 mm and a uniformity coefficient of 1.2 to 1.6. medium depth: 0.9 to 1.8 m. abdul-fattah mohamed ali 45 vol.12 no.1 (march 2011) filtration rate : 100 l/min m 2 ( 6.0 m 3 /h m 2 ) filtration runs duration: 8 to 24 h. mode of operation: constant level with constant flow rate. water level above sand during filtration run : to be maintained at 1.2 m. underdrain system : false-floor equipped with long-stem plastic nozzles. backwash mode : air scour followed by air plus water then only water. remarks concerning filtration of secondary effluent 1. a properly designed and operated filtration system should remove 65 to 80% of the suspended solids in the wastewater. 2. the specified filtration rate of 100 l/min m 2 would ensure that more than 90% of the 10 µm size particles are removed ; which is of particular relevance to the following disinfection process by uv irradiation. 3. filters should be backwashed at least once every 24 h to avoid formation of mudballs (i.e. agglomeration of biological floc, dirt and sand) as well as buildup of grease. 4. the specified mode of operation and filtration run duration would ensure that loss of filtration medium is minimized / prevented. filtration conceptual and basic design elements are given in appendix a. disinfection the relevant indicator microorganism for disinfection is faecal coliform whose count should be around 100 mpn/100 ml for crop irrigation (abdulraheem [2] ; el-wakeel et al. [3]) the two widely-used disinfection methods for this purpose are chlorination and uv irradiation. each method has its merits and drawbacks. to appreciate the adopted design approach in this work, some relevant characteristics of filtered secondary effluent are in order. this kind of water contains nh3 ranging from 18 to 30 mg/l, so that when it is chlorinated, two outcomes are possible depending on the amount of cl2 added (metcalf and eddy [6] ; qasim [15]) : a) formation of chloroamines (combined chlorine) with partial or total removal of nh3 but before the breakpoint is reached. b) the breakpoint is passed with an amount of free cl2 present. combined chorine requires 100 times the contact time of free cl2 to achieve the same microorganism kill level (tebbutt [14]). therefore, if a relatively small amount of cl2 is added (outcome (a)) , the required contact time will be excessive (of the order of days). conversely, to limit the contact time to the range of 30 to 90 min. with free cl2, an excessive amount of cl2 must be added (outcome (b)). this is uneconomical and may result in unacceptable levels of dbp’s. therefore, chlorination on its own is not a costeffective option to disinfect wastewater that has not been nitrified/ denitrified. an alternative approach, adopted in this work, would be to irradiate the wastewater using uv light and then to chlorinate it to a limited extent to utilize chloroamines as combined chlorine residual to maintain the water suitability until it reaches the agricultural fields. in this case only a fraction of the nh3 present is converted to chloroamines, the reuse of domestic wastewater for irrigation: conceptual and basic design elements 46 vol.12 no.1 (march 2011) predominant species of which is monochloroamine (nh2cl) due to the water ph and the cl2 to nh3 molar ratio. the necessary concentration of nh2cl is a function of the distance/time required for the water to reach its destination. stoichiometrically four weights of cl2 are required to convert one weight of nh3 to nh2cl. it is also noteworthy that combined chlorine does not form dbp’s (metcalf and eddy [7]; degremont [12]). uv irradiation (metcalf and eddy [8] ; suntec environmental [17] ; tchobanogolous et al. [18]) this system is based on the widely-used low-pressure low-intensity uv lamp with a useful life of about one year. the system shall constitute three parallel channels to match the filtered water exiting the three aforementioned parallel filters. the basic design elements of each uv channel are as follows: wetted dimensions : 0.6×0.6 m no. of uv banks : one lamp configuration (placement) : horizontal no. of lamp modules per bank : 8 no. of lamps per module : 8 no. of lamps per bank : 64 effective arc length of lamp : 1.47 m diameter of lamp’s quartz sleeve : 23 mm lamp spacing : 75 mm (center to center) power consumption per bank : 5 kw lamp current & voltage : 0.34 amp at 220 volt diffuser no. and type : two ; perforated plate. one upstream and one downstream of bank. each perforated plate has 256 (16×16) 13-mm holes; hole spacing 37.5 mm (center to center). head loss across uv-bank including diffusers: 32 cm wc; this may be overcome by two 16-cm steps one upstream and on downstream of bank. all the aforementioned elements specifications are typical. however, they are collectively consistent and match the given wetted dimensions of the uv channel. this matching, plus the employed of diffusers (to ensure plug-flow condition) is necessary to ascertain that an acceptable average uv intensity value is achieved within the bank as the ww passes through it. details of uv irradiation system basic design elements are given in appendix b. chlorination as pointed out earlier, the aim of this process is to produce the necessary concentration of nh2cl in the filtered, disinfected secondary effluent to maintain its suitability until it is utilized for irrigation. the three wastewater streams exiting the uv irradiation system should transfer the water to a buffer basin of suitable size. typically an effective volume equivalent to about three-hour flow is used. for the capacity under consideration this would result in a 1500 m 3 size basin which could be constructed of three parallel basins, each with dimensions of 4×5×25 m (d×w×l). therefore, each uv channel shall be connected to one 500 m 3 basin. it is envisaged that three separate chlorination systems, one per basin, should be employed. each system consists of a pump, an educator and a nozzl arrangement plus the necessary piping connecting them. the centrifugal pump withdraws water from the upstream end of the basin , pumps it through abdul-fattah mohamed ali 47 vol.12 no.1 (march 2011) the educator whose gas side is connected to the cl2 supply line from the cl2 cylinder, then returns the chlorinated water back to the downstream end of the basin through a hanging – nozzle type multiple diffuser mixer placed across the width of the channel as illustrated in fig .( 1 ) (qasim [16]). figure 1 schematic diagram of chlorination system arrangement. cl2 reacts readily with nh3 to form chloroamines and in order to utilize all the supplied cl2 for this purpose (i.e to minimize undesirable side reactions) the chlorinated water should have an excess of nh3. this point is illustrated in appendix c which gives the basic design elements of a chlorination system for an example case. final note the presented design has a turn down ratio of 3:1 ; i.e it can be operated at 33%, 67% or 100% of its design capacity because it is based on three parallel trains. such flexibility is important due to seasonal variation in irrigation needs. additionally, it serves to facilitate maintenance requirements. 1 m 0.5 m 1 m 5 m nozzle eductor cl2 gas pump by-pass line filtered disinfection ww (from upstream end of buffer basin) pump buffer basin (downstream end) 4 m chlorinated ww reuse of domestic wastewater for irrigation: conceptual and basic design elements 48 vol.12 no.1 (march 2011) conclusions secondary effluent from a conventional medium–rate activated sludge process may be filtered, uv irradiated and partially chlorinated (chloraminated) to render it suitable for crop irrigation. the necessary conceptual and basic design elements for these steps have been given to enable local municipal authorities to appreciate the requirements as well as to serve as a basis for the subsequent phases of detailed design and execution of such projects. references [1] vernick, a.s. and e.c. walker, editors (1981) “handbook of wastewater treatment processes”, marcel dekker, new york, p's. 30,32,40. [2] abdulraheem, m.y. (2008) “public health aspects of wastewater treatment and reuse in kuwait”, in “wastewater reclamation and reuse”, al-sulaimi and asano, editors, arab school on science and technology, kuwait, new age int., new delhi, pp.135-180. [3] el-wakeel, a.f, el-nashar, b.m. and o.a. al-hamad (2008) “reuse of sewage effluents for irrigation”, in “wastewater reclamation and reuse”, ibid.pp. 244259. [4] metcalf & eddy,inc. (2003) “wastewater engineering treatment and reuse”, 4 th edition, revised by tchobanoglous,g. , burton,f.l. and h.david stensel, mcgraw-hill , newyork, p.’s.1080,1328. [5] ibid. pp.1044-1096. [6] ibid. pp. 1231-1239. [7] ibid. p. 1257. [8] ibid. pp. 1298-1329. [9] abdul-fattah, a.m.a(2002) ”conceptual treatment scheme for one stream of intended rasafa potable water works”, report no.am-r3-02-rp-r4,revised issue, al-magd general co.,baghdad. pp. 25-28. [10] crites,r. and g. tchobanoglous (1998) “small and decentralized wastewater management systems”, mcgraw-hill , new york, pp. 813-820. [11] degremont (2007) “water treatment handbook”,7 th edition, lavoisier publishing , paris, chapter 13 sec.’s 3,5. [12] ibid. chapter 17 sec. 6.5. [13] tebbutt , t. h. y. (1998) “principle of water quality control”, 5 th edition , butterworth-heinemann , oxford, pp.169174. [14] ibid. p.206. [15] qasim,s.r. (1985) “wastewater treatment plants planning, design and operation”, cbs college publishing , new york, p.384. [16] ibid. p.388. [17] suntec environmental, inc .(2003) “uv disinfection of secondary effluent , lpx200 system, nsf international/usepa” , etv report 03/09/wqpc-swp. [18] tchobanoglous,g., loge,f., darby,j. and m. devries (1995) “design of uv disinfection system”, usepa 4 th national wastewater treatment technology transfer workshop , kansas city. [19] kiely,g.(1997) “environmental engineering”, irwin/ mcgraw-hill, united kingdom, p. 556. abdul-fattah mohamed ali 49 vol.12 no.1 (march 2011) [20] wilson, f. (1981) “design calculations in wastewater treatment”, e. & f.n. spon, london, p.124. abbreviations bod5: five-day biochemical oxygen demand dbp: disinfection by-products f m : food to microorganism ratio fog: fat, oil and grease mpn: most probable number s.s: suspended solids uv: ultraviolet ray wc: water column ww: wastewater appendix a flirtation system conceptual and basic design elements filtration area = 12600 (m 3 /d)/24(h /d) 6( m 3 /h m 2 ) = 87.5m2. no. of filters and arrangement : three parallel filters, each having a filtration area of 30 m 2 . 1) each filter shall be constituted of two side-by-side compartments with a common in-between channel. each compartment shall be 5×3 m. the intermediate channel between any two compartments shall be divided into two parts. the lower part serves as the filtered water outlet during a filtration run or as the backwash water inlet during a backwash run. the upper part remains empty during a filtration run or serves as the backwash water outlet during a backwash run. filtering medium, i.e. sand, specifications : 1) effective size d10 =2.38 mm (u.s. sieve no.8) 60% size d60 = 3.36 mm (u.s. sieve no.6) coefficient of uniformity cu = d60 d10 =1.41. 2) amount of sand : sand depth = 1.2 m sand volume = (1.2 m) (15 m 2 compart . ) = 18 m 3 /compartment average relative density of sand = 2.6 (range 2.55 to 2.65) mass of sand = (18) (2.6) =46.8 ≈ 47 tonne per compartment total amount of sand = (47) (6) = 282 tonne. 3) sand size breakdown, basis: one compartment (47000) (0.1) = 4700 kg passing through sieve no.8. (47000)(0.5) = 23500 kg passing through sieve no.6 but blocked by sieve no.8. (47000)(0.4) = 18800 kg passing through sieve no.4 (4.76 mm) but blocked by sieve no.6. reuse of domestic wastewater for irrigation: conceptual and basic design elements 50 vol.12 no.1 (march 2011) sieve no. size range (mm) mass % mass (kg) 4-6 4.76 to 3.36 40 18 800 6-8 3.36 to 2.38 50 23 500 <8 < 2.38 10 4 700 ∑= 47 000 no. of long stem-plastic nozzles on false-floor on the false-floor of each compartment whose dimensions are 5×3 m, there shall be 24×14 = 336 nozzles with a nozzle spacing of 20 cm (center to center). therefore, total number of nozzles for the filtration system shall be (336) (6) = 2016. backwash run sequence and flow rates per filter 1) air scour at a rate of 60 to 70 m 3 /min for couple of minutes. 2) air scour plus 12 to 18 m 3 /min of backwash water for five to ten minutes. 3) stopping air scour and doubling the backwash water rate for three minutes during the backwash run, lasting 10 to 15 minutes, the filter influent is maintained ; acting as a cross-wash flow to sweep particles from the top of the filter bed in the two compartments (i.e. surface sweep) to the intermediate channel. the backwash plus surface sweep water should be recycled to the primary clarification system of the activated sludge process appendix b uv irradiation system conceptual and basic design elements determination of required uv dose : in uv irradiation system design, the indicator microorganism is total coliform. faecal coliform count may constitute one-sixth to one-third of total coliform count (kiely [19] ; wilson [20]). for a total coliform count of 500 mpn/100 ml in a filtered secondary effluent, a uv dose of 20 mj/cm 2 is required. this dose would result in a faecal coliform count of around 100 mpn/100 ml. determination of exposure time required in uv bank : the uv dose (d) is related to the exposure time (t) by: d = (i) (t) , where i is the average uv intensity in the uv bank. abdul-fattah mohamed ali 51 vol.12 no.1 (march 2011) in the uv irradiation system considered, i may range from 4 to 14 mw/cm 2 . taking the minimum i value of 4 mw/cm 2 , t = d i = 20 (mj /cm 2 ) 4 (mw /cm 2 ) = 5 s determination of flow rate in uv channel : average water velocity in uv bank u = l t , wher l is the effective arc length of lamp. u = 1.47 (m)/5 (s) = 0.294 m/s. considering aging and fouling of uv lamps during one-year operation, design average velocity is taken as one-half u. therefore, udesign = 0.294 2 = 0.147 m/s free cross-sectional flow area in bank = 0.33 m 2 design flow rate per channel = (0.147)(0.33) = 0.0485 m 3 /s ≡4191 m 3 /d (≅ 4200 m 3 /d). design flow rate per uv lamp = 0.0485 m 3 /s 1000 l m 3 (60 s/min ) (64 lamp /bank ) = 45.5 l/min lamp which is a reasonable design figure. determination of head loss across diffusers and bank: the flow area of the perforated plate diffuser is 5 to 10% of the channel flow area. hence, a 0.6×0.6 m plate with 16×16, 13-mm holes, would result in a diffuser area which is 9.4 % of the channel flow area. the head loss per diffuser is calculated as follows: hl= k uhole 2 2g , where k = 1.56 the headloss coefficient and uhole= qchannel /(16×16) ( π×0.0132 4 ) , qchannel = 0.0485 m 3 /s the channel flow rate. therefore hl per diffuser = 0.16 m wc. the head loss per uv bank is calculated as follows: hl= k ubank 2 2g , k = 1.8 , the bank head loss coefficient, ubank = 0.147 m/s. hence, hl = 1.98×10 -3 m or 2 mm wc which is negligible. appendix c chlorination system conceptual and basic design elements per buffer basin for example case nh3 in filtered ww : 20 mg/l (assumed) nh3 to be converted to nh2cl : 4 mg/l (assumed ; i.e. one-fifth of nh3 present) cl2 amount required : 4×4 = 16 mg/l chlorinated water flow = (0.25)(4200) = 1050 m 3 /d = 43.75 m 3 /h (12.15 lps) (cf. note (1) below) pipe size (pump, eductor) : 3" (velocity~ 2.5 m/s) nozzle size * : 1" (velocity ~ 22 m/s) cl2 flow from cylinder to eductor : about 200 mg/s (16 mg/l×12.15 l/s) reuse of domestic wastewater for irrigation: conceptual and basic design elements 52 vol.12 no.1 (march 2011) concentration of nh2cl in chlorinated ww : (4/17)(51.45) ≅ 12 mg/l concentration of nh2cl in irrigation ww : (12)(0.25) = 3 mg/l at the aforementioned cl2 consumption, a oneton (907 kg) cl2 cylinder will last more than two weeks for the three basins (~600 mg cl2/s) * in this example case, the nozzle is simply a 3" to 1" reducer. notes: 1) fraction of chlorinated water flow from total water flow should be more than fraction of nh3 converted to nh2cl to total nh3 present to ensure excess nh3 in chlorinated water (e.g. one-fourth vs. one-fifth in the above example) 2) pump head to be determined following detailed piping design. مفاهيم و عناصر التصميم االساس لمراحل جعل مياه الصرف الصحي المعالجة صالحة لسقي المزروعات : الخالصة تجعم مه انضزَري عهى انسهطاث , خصُصًا اثىاء اشٍز انصٍف انذارة, ان شذت انمٍاي َانجفاف انذي ٌشٍدُي انعزاق ٌبٍه ٌذا انعمم مفاٌٍم َعىاصز انتصمٍم . انبهدٌت اعتماد مشارٌع اعادة استعمال انمٍاي انمصزفت انمعانجت كمٍاي انصزف انصذً دٍث تشتمم ٌذي انمزادم عهى انتزشٍخ َانمعانجت باالشعت فُق انبىفسجٍت . االساس نمزادم جعم ٌكذا مٍاي صانذت نسقً انمزرَعاث كمثال نتُضٍخ انتصامٍم انمقتزدت انمتسمت بانبساطت انىسبٍت 50000 تم اعتماد تجمع سكاوً رٌفً عدد وفُسً .َمه ثم انكهُرة األفادة مه انمعهُماث انمقدمت نهشزَع بطُري انتصامٍم انتفصٍهٍت َانتىفٍذ نٍذي (2اٌضاح انمتطهباث َ (1ٌٍدف انعمم انى . َانفاعهٍت .انمشارٌع iraqi journal of chemical and petroleum engineering vol.13 no.3 (september 2012) 3545 issn: 1997-4884 the control of non isothermal cstr using different controller strategies zahra'a f. zuhwar university of technology, chemical engineering department abstract in all process industries, the process variables like flow, pressure, level, concentration and temperature are the main parameters that need to be controlled in both set point and load changes. a control system of propylene glycol production in a non isothermal (cstr) was developed in this work where the dynamic and control system based on basic mass and energy balance were carried out. inlet concentration and temperature are the two disturbances, while the inlet volumetric flow rate and the coolant temperature are the two manipulations. the objective is to maintain constant temperature and concentration within the cstr. a dynamic model for non isothermal cstr is described by a first order plus dead time (fopdt). the conventional pi and pid control were studied and the tuning of control parameters was found by ziegler-nichols reaction curve tuning method to find the best values of proportional gain (kc), integral time ( i) and derivative time ( d). the conventional controller tuning is compared with imc techniques in this work and it was found that the ziegler –nichols controller provides the best control for the disturbance and the worst for the set-point change, while the imc controller results show satisfactory set-point responses but sluggish disturbance responses because the approximate foptd model has relatively small time delay. feedforward and feedforward combined with feedback control systems were used as another strategy to compare with above strategies. feedforward control provides a better response to disturbance rejection than feedback control with a steady state deviation (offset). thus, a combined feedforward-feedback control system is preferred in practice where feedforward control is used to reduce the effects of measurable disturbances, while feedback trim compensates for inaccuracies in the process model, measurement error, and unmeasured disturbances. also the deviation (offset) in feedforward control was eliminated. keywords: non isothermal cstr, ziegler –nichols reaction curve, imc control and feed forward control. introduction the non-isothermal cstr is an important industrial process that introduces the opportunity for a diverse range of process dynamics. this work involves the control of the production of propylene glycol by the hydrolysis of propylene oxide. iraqi journal of chemical and petroleum engineering university of baghdad college of engineering the control of non isothermal cstr using different controller strategies 36 ijcpe vol.13 no.3 (september 2012) -available online at: www.iasj.net feedback controller settings were calculated using the ziegler-nichols and imc tuning. different control strategies were studies; these strategies are feedback, feedforward and feedforward with feedback control. the selection of good control algorithm depends upon the performance comparison of different possible control techniques and selecting the best for the desired condition. a control system designed for a particular process should provide fast and accurate changes for both the set point changes as well for load changes. model based controllers are now popular because of their ability to handle a process with dead time. one type of model based control is internal model control (imc) which has both an open loop and a closed loop system. imc tuning is referred to as a set of tuning procedures based on the internal model principle. the underlying idea behind internal model methodologies is to compute a controller and/or to set its values relative to a prescribed response formulated as a prescribed (internal) model. in this way, imc designs belong to the class of model based control settings, whose origin can be traced back to the proportional integral-derivative (pid) tuning method proposed by dahlin [1]. feedforward control strategies was studied in this work. feedforward uses the measurement of an input disturbance to the plant as additional information for enhancing single loop pid control performance. this measurement provides an "early warning" that the controlled variable will be upset some time in the future. with this warning, the feedforward controller has the opportunity to adjust the manipulated variable before the controlled variable deviates from its set point. note that the feedforward controller that does not use an output of the process. this is the first example of a controller that does not use feedback control. feedforward is usually combined with feedback so that the important features of feedback are retained in the overall strategy [2]. feedforward control was not widely used in the process industries until the 1960s [3]. since then, it has been applied to a wide variety of processes that include boilers, evaporators, solids dryers, direct fired heaters, and waste neutralization plants [4]. however, the basic concept is much older and was applied as early as 1925 in the three element level -control system for boiler drums. process description the non-isothermal continuous stirred tank reactor (cstr) where desired propylene glycol is produced by the hydrolysis propylene oxide is shown in fig (1) fig.1, continuous stirred tank reactor the feed stream consists of: (1) an equivalent mixture of propylene oxide and methanol. (2) water. a cooling coil has been located for use in the hydration of propylene oxide; the reaction equation is: the reaction is exothermic and takes place readily at room temperature when catalyzed by sulfuric acid [5]. propylen e methanol water t , ca cooling coil oh oh ch3 ch ch2 h2so4 + h2o ch3 o ch ch2 zahra'a f. zuhwar -available online at: www.iasj.net ijcpe vol.13 no.3 (september 2012) 37 the operating conditions used are given in table (1). table 1-a, operating conditions [11] volumetric flow rate inlet 326.3 ft 3 /h (9.24m 3 /h) volume of liquid in reactor 40.1ft 3 (1.136m 3 ) temperature of feed inlet 535 r (297 k) temperature in reactor 564 r (313.35 k) coolant temperature 545 r (302.7 k) concentration of propylene oxide inlet 0.132 lbmol/ft 3 (2.11kmol/m 3 ) concentration of propylene oxide in reactor 0.08316 lbmol/ft 3 (1.33 kmol/m 3 ) table 1-b,properties [11] ideal gas constant 1.987btu/ibmol.r (8.314 kj/kmol.k) heat of reaction -36652btu/ibmol (85278.6 kj/kmol) activation energy 32400btu/ibmol (75385.43 kj/kmol) overall heat transfer coefficient 100btu/h.ft 2 .f (1.36 kj/h.m 2 .k) area for heat exchange 40 ft 2 (3.715 m 2 ) density* heat capacity 52.857 btu/ft 3 .f (2.36 kj/m 3 .k) pre exponential factor (ko) 16.96*10 12 (h -1 ) mathmatical model mathematical models of chemical systems were developed for many reasons. thus, they may be constructed to assist in the interpretation of experimental data for predicting the consequence of changes of system input or operating conditions, for deducing optimal system or operating conditions and for control purposes. usually there is an interest for dynamic model made to design and/or test the proposed control system. the dynamic and steady state simulation model for non isothermal (cstr) consists of a system of equations based on mass and energy balances on the continuous stirred tank reactor (cstr). 1. overall material balance dt dv outin in    ...(1) assuming a constant amount of material in the reactor dt dv =0, we find that:  outin in  if we also assume that the density remains constant, then:   out in and dt dv =0 2. balance on component a the balance on component a, assuming a constant volume reactor, is: rv a c ai c dt a dc v   ...(2) where r is the rate of reaction per unit volume 3. energy balance around tank the energy balance, assuming a constant volume, heat capacity and density, is: )()()( c ttuarvht i t p c dt dt p cv   ...(3) )()()( ref ttpcref thth  …(4) where (-δ h)r v is the rate of energy contributed by the exothermic reaction. the reaction rate per unit volume (arrhenius expression) is: the control of non isothermal cstr using different controller strategies 38 ijcpe vol.13 no.3 (september 2012) -available online at: www.iasj.net a c rt e o kr )exp(   ...(5) where the reaction is first order in propylene oxide concentration. linearization of dynamic equations the stability of the nonlinear equations can be determined by finding the following state space form: buaxx  and determining the eigen values of the a (state space) matrix. the nonlinear dynamic equations are: a c rt e o k a c v aic vdt a dc t a cf )exp(),( 1    ...(6) c t p cv ua t p cv ua a c rt e o k p c h t v i t vdt dt t a cf       )exp()(),( 2 ...(7) the state and input variables can be defined in deviation variable form:          stt ascac x          csttc s u  the state space a matrix is: [ ( ) ( ) ] where )exp( rts e o kks   ) 2 )(exp(' rts e rts e o ksk   the state space b matrix is: [ ] model identification the imc tuning is based on an assumed process model and leads to analytical expressions for the controller settings [6]. in this work, the process model is described by first order plus dead time (fopdt) model. the fopdt model parameters are found from the dynamic step response. for this foptd model, sundaresanand krishnaswamy’s method is used. this method avoids the use of the point of inflection construction entirely to estimate the time delay. they proposed that two times, (t1) and (t2) be estimated from a step response curve in figs (3,4,5 and 6) corresponding to the 35.3% and 85.3% response times, respectively. the time delay (td) and time constant (τ) are then estimated from the following equations: td = 1.3 t1 0.29 t2 …(8) τ = 0.67 (t2-t1) ...(9) these values of td and τ approximately minimize the difference between the measured response and the model, based on a correlation for many data sets [6]. the transfer functions for step change in manipulated variables and disturbances are given by these equations: gp1 = )( ca(s) s = 14251.0 0006324.0 s e – 0.0211 s zahra'a f. zuhwar -available online at: www.iasj.net ijcpe vol.13 no.3 (september 2012) 39 gd1 = )( ca(s) scai = 14605.0 057.2   s e – 0.3425s gp2 = )( t(s) stc = 14644.0 565.1 s e – 0.0552 s gd2 = )( t(s) sti = 146.0 746.6 s e – 0.0591 s control strategies 1. internal model control (imc) a more comprehensive model-based design method, internal model control (imc), was developed by garcia and morari [7] and rivera et al., [8]. the imc method is based on the simplified block diagram as shown in fig (2). fig.2, imc control a process model ğ and the controller output p are used to calculate the model response, ỹ. the model response is subtracted from the actual response y and the difference y ỹ is used as the input signal to the imc controller gc * . in general, y ≠ ỹ due to modeling errors (g ≠ ğ) and unknown disturbances d≠ 0 that are not accounted for in the model. the imc controller is designed in two steps: step 1.the process model is factored as ğ=ğ+ğ ...(10) where ğ+ contains any time delays and right-half plane zeros. in addition, ğ+ is required to have a steady-state gain equal to one in order to ensure that the two factors in the equation are unique. step 2.the controller is specified as gc * = ~ g f ...(11) where f is a low-pass filter with a steady-state gain of one. it typically has the form [8]: n c f )1( 1    τc is the desired closed-loop time constant. parameter n is a positive integer. the usual choice is n= 1. note that the imc controller in eq. (11) is based on the invertible part of the process model, ğ-, rather than the entire process model, ğ [6]. the choice of design parameter τc is a key decision in imc design method. several imc guidelines for τc have been published for the foptd model. 1. τc /td > 0.8 and τc >0.1 τ [8] 2. τ > τc > td [9] 3. τc =td [10] 2. feedforward control feedforward control is a powerful strategy for control problems where important disturbance variable can be measured on-line. by measuring disturbances and taking corrective action before the controlled variable is upset, feedforward control can provide dramatic improvements for regulatory control. the chief disadvantage of feedforward control is that the disturbance variable must be measured (or estimated) on-line, which is not always possible. the control of non isothermal cstr using different controller strategies 40 ijcpe vol.13 no.3 (september 2012) -available online at: www.iasj.net feedforward controllers tend to be custom-designed for specific applications, although a lead-lag unit is often used as a generic feedforward controller. the design of a feedforward controller requires knowledge of how the controlled variable responds to changes in the manipulated variable and the disturbance variable. this knowledge is usually represented as a process model. steady-state models can be used for controller design; however, it may then be necessary to add a lead-lag unit to provide dynamic compensation. feedforward controllers can also be designed by using dynamic models [6]. the design equation for feedforward control is: )( )( )( sgp sgd sg ff  ...(12) this equation demonstrate that feedforward control depend heavily on a good knowledge of the process model (gp, gd). perfect control necessitates perfect knowledge of gp and gd, which is not practically possible and this is considered the main drawback of feedforward control [11]. in practical applications, feedforward control is normally used in combination with feedback control. feedforward control is used to reduce the effects of measurable disturbances, while feedback trim compensates for inaccuracies in the process model, measurement error, and unmeasured disturbances. in a typical control configuration, the outputs of the feedforward and feedback controllers are added together, and the sum is sent as the signal to the final control element. another useful configuration for feedforward-feedback control is to have the feedback controller output serve as the set point for the feedforward controller [6]. results and discussions the dynamic and model responses are studied for step change in the manipulated variables (υ and tc) and in the disturbance variables (cai and ti) in order to study these effect on the controlled variables (ca and t). figs. (3) and (4) show dynamic and model responses for the concentration of propylene oxide in reactor (ca) with time by step change in the volumetric flow rate for inlet (υ) and the concentration of propylene oxide in feed stream (cai), respectively. in figs. (3) and (4), it can be seen that the increase in the input flow rate is directly proportional to the concentration of propylene which led to a decrease in it. fig.3, concentration versus time at step change in input flow rate fig.4, concentration versus time at step change in input concentration 0 0.5 1 1.5 2 2.5 -2.5 -2 -1.5 -1 -0.5 0 0.5 t(hr) c a step response curve: dynamic step response model step response 0 0.5 1 1.5 2 2.5 0 1 2 3 4 5 6 7 8 x 10 -4 t(hr) c a step response curve: dynamic step response model step response ∆ c a zahra'a f. zuhwar -available online at: www.iasj.net ijcpe vol.13 no.3 (september 2012) 41 figs. (5) and (6) show dynamic and model responses for temperature of reactor with time by step change in the temperature of coolant (tc) and the temperature in feed stream (ti), respectively. from figs. (5) and (6), it can be seen that the increase in the temperature of coolant is directly proportional to the temperature of the reactor; also the increase in the input temperature was found to lead to increase in it. in this work, the unit step change is taken in the set point and disturbance of concentration and temperature within reactor using feedback, feedforward and feedforward with feedback controllers. fig.5, temperature versus time at step change in coolant temperature fig.6, temperature versus time at step change in input temperature figs (7) and (8) indicate the comparison among set point response of all used controllers for control on concentration and temperature, respectively. these figures show that the imc controller provides an excellent set point response, while the ziegler – nichols controller provides the worst for the set point change because significant overshoots and longer settling times, and feedforward control provides sluggish for the set point change when reaching the steady state in a long time. fig.7, the comparison among set point response of all used controllers for control on concentration fig.8, the comparison among set point response of all used controllers for control on temperature table (2) shows that the value of itae for unit step change in set point of the imc controller is less than the other controllers. 0 0.5 1 1.5 2 2.5 -1 0 1 2 3 4 5 6 7 t(hr) t step response curve: dynamic step response model step response 0 0.5 1 1.5 2 2.5 -0.2 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 t(hr) t step response curve: dynamic step response model step response ∆ t 0 0.5 1 1.5 2 2.5 3 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 t c a pi pid imc ff ff-fb ∆ c a 0 0.5 1 1.5 2 2.5 3 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 t t pi pid imc ff ff-fb ∆ t the control of non isothermal cstr using different controller strategies 42 ijcpe vol.13 no.3 (september 2012) -available online at: www.iasj.net table 2-a, itae values for control of concentration within reactor (set point change) table 2-b, itae values for control of temperature within reactor (set point change) controllers itae pi controller 0.052 pid controller 0.0166 imc controller 0.0108 feedforward controller 0.0747 feedforward with feedback controller 0.0161 figs (9,10,11and12) indicate to the comparison among disturbance response of all used controllers. these figures show that the ziegler – nichols controller provides the best control for the disturbance, while the imc controller produces an unacceptably slow disturbance response because the value of τi is very large. feedforward controller provides a better response to disturbance than feedback controller with the remaining deviation (offset). thus a combined feedforward-feedback control system is preferred in practice where deviation (offset) in feedforward controller has disappeared and feedforward controller is used to reduce the effects of measurable disturbances, while feedback trim compensates for inaccuracies in the process model, measurement error, and unmeasured disturbances. fig.9, the comparison among load response of pi, pid and imc controllers for control on concentration fig.10, the comparison between load response of ff and ff-fb controllers for control on concentration fig.11, the comparison among load response of pi, pid and imc controllers for control on temperature 0 0.5 1 1.5 2 2.5 3 -0.2 -0.15 -0.1 -0.05 0 0.05 t(hr) c a pi pid imc 0 0.5 1 1.5 2 2.5 3 -0.04 -0.02 0 0.02 0.04 0.06 0.08 t(hr) c a ff ff-fb 0 0.5 1 1.5 2 2.5 3 -0.2 0 0.2 0.4 0.6 0.8 1 1.2 t(hr) t pi pid imc controllers itae pi controller 0.0105 pid controller 0.0038 imc controller 0.0026 feedforward controller 0.0755 feedforward with feedback controller 0.0036 zahra'a f. zuhwar -available online at: www.iasj.net ijcpe vol.13 no.3 (september 2012) 43 fig.12, the comparison between load response of ff and ff-fb controllers for control on temperature table (3) shows that the value of itae for unit step change in disturbance of the feedforward-feedback controller is less than the other controllers. table 3-a, itae values for control of concentration within reactor (disturbance change) table 3-b, itae values for control of temperature within reactor (disturbance change) conclusions in this work, the mathematical model of the dynamic behavior of non isothermal process in a continuous stirred tank reactor (cstr) was studied and developed. the unit step change is taken in the set point and disturbance of concentration and temperature within the reactor using pi, pid, imc, feedforward and feedforward with feedback controllers. a control system designed for process should provide fast and accurate changes for both the set point changes as well for a load changes. the following conclusions can be drawn: 1. feedback controller settings were calculated using the ziegler-nichols and imc tuning and it was found that the ziegler-nichols controller provides the best control for the disturbance with a small maximum deviation and the worst for the set point change where it has significant overshoot, while the imc controller produces satisfactory set-point responses and reaches the steady state in less time with lower overshoot, but an unacceptably slow disturbance responses because the approximate foptd model has relatively small time delay. 2. feedforward and feedforward combined with feedback control systems were used as another strategy to be compared with the above strategy. feedforward controller provides slow responses for the set point change when reaching the steady state in a long time but it produces excellent responses to disturbance change than feedback controller with the remaining deviation (offset). thus, a combined feedforward-feedback control system is preferred in practice where deviation has disappeared. in practical applications, feedforward control is normally used in combination with feedback control. 0 0.5 1 1.5 2 2.5 3 -5 -4 -3 -2 -1 0 1 x 10 -3 t(hr) t ff ff-fb controllers itae pi controller 0.0055 pid controller 0.0025 imc controller 0.0717 feedforward controller 0.0076 feedforward with feedback controller 0.0014 controllers itae pi controller 0.0428 pid controller 0.0250 imc controller 0.4460 feedforward controller 8.0943e004 feedforward with feedback controller 5.7434e004 the control of non isothermal cstr using different controller strategies 44 ijcpe vol.13 no.3 (september 2012) -available online at: www.iasj.net feedforward control is used to reduce the effects of measurable disturbances, while feedback trim compensates for inaccuracies in the process model, measurement error and unmeasured disturbances. nomenclature kc proportional gain (pressure/error) τi integral time (hr) τd derivative time (hr) a area for heat exchange (m2) ca concentration of propylene oxide in reactor (kmol/m3) cas concentration of propylene oxide in reactor at steady state (kmol/m3) cai concentration of propylene oxide in feed stream( kmol/m3) cp heat capacity (kj/kg*k) υ volumetric flow rate for inlet (m3/hr) υs volumetric flow rate at steady state (m3/hr) ko pre exponential factor (hr-1) r ideal gas constant (kj/kmol*k) r rate of reaction per unit volume (kmol/m3*hr) t time (hr) tref temperature of reference (k) tc temperature of coolant (k) tcs temperature of coolant at steady state (k) ti temperature of feed inlet ( k ) t temperature of reactor ( k ) ts temperature of reactor at steady state (k) v volume (m3) u overall heat transfer coefficient (kj/hr*m2* k) δe activation energy (kj/kmol) (-δh) heat of reaction (kj/kmol) ρ density (kg/m3) td time delay (hr) ʈ time constant (hr) ʈc desired closed loop time constant (hr) abbreviation cstr continues stirred tank reactor fopdt first order plus dead time pi proportional integral controller pid proportional integral derivative imc internal model control ğ process model ğ+ non invertible part of the process model ğinvertible part of the process model gc* transfer function for imc controller p controller output ỹ model response y actual response f low pass filter gp transfer function for process gd transfer function for disturbance gff transfer function for feedforward ff feedforward controller ff-fb feedforward feedback controller itae integral time absolute error references 1. dahlin, e. g., (1968), " designing and tuning digital controllers", inst. control syst., 41, pp. 77-81. 2. thomas e. marlin, (2000), "process control", 2 nd ed, mcgraw hill, chapter 15. 3. shinskey, f. g., (1996), " process control systems: application, design, and tuning", 4 th ed. mcgrawhill, new york, chapter 7. 4. shinskey, f. g., hordeski, m. f. and liptak, b. g., (1995), " feedback and feedforward control", in instrument enginner , s handbook: vol. 2, process control, 3d ed., b. g. liptak (ed.), chilton book co., randor, pa, section 1.8. 5. fogler, h. scott, (1992), "elements of chemical reaction engineering" 2 nd ed, chapter 8, pp 405. zahra'a f. zuhwar -available online at: www.iasj.net ijcpe vol.13 no.3 (september 2012) 45 6. dale e. seborg, thomas f. edgar and duncan a. mellichamp, (2004), "process dynamics and control", 2 nd ed, john wiley &sons, inc. ,chapter 12. 7. garcia, c. e., and morari, m., (1982), "internal model control i. a unifying review and some new results", ind. eng. chem. process des. dev., pp. 21, 308. 8. rivera, d. e., morari, m., and skogestad, s., (1986), internal model control.4. pid controller design", ind. eng. process design dev.,pp. 25, 252. 9. chien, i. l., fruehauf, p. s., (1990), "consider imc tuning to improve controller performance", j. chem. eng. prog , pp. 33-41. 10. skogestad, s., (2003),"simple analytic rules for model reduction and pid controller tuning", j. process control 13, 291. 11. stephanopoulos, g., (1984), "chemical process control", an introduction to theory and practice, prentice-hall india. iraqi journal of chemical and petroleum engineering vol.13 no.4 (december 2012) 3545 issn: 1997-4884 hydrodynamic pressure gradient correlation of some iraqi oil wells riyadh hazim fawzi university of baghdad, college of engineering, petroleum engineering department, baghdad, iraq abstract empirical equation has been presented to predict the optimum hydrodynamic pressure gradient with optimum mud flow rate (one equation) of five iraqi oil wells to obtain the optimum carrying capacity of the drilling fluid ( optimum transport cuttings from the hole to the surface through the annulus). this equation is a function of mud flow rate, mud density and penetration rate without using any charts or graphs. the correlation coefficient accuracy is more than 0.9999. keywords correlation, drilling, pressure gradient, mud flow rate, penetration rate and mud density introduction saleh [1] has taken the actual data from iraqi oil fields (five wells) in order to determine the optimum flow rate using graphical solution. four of the wells are production wells (no.1, 2, 3, 4) and the fifth one is observation well (no.5). the hydrodynamic pressure gradient of the wells can be expressed by saleh [4] using the following equation: d li l pt d pbh i j i .)( 1     ...(1) and:    j i lid 1 …(2) saleh [1] draws five graphs of five wells by using the relation between the hydrodynamic pressure gradient and mud flow rate to choose the optimum mud flow rate. in the previous studies of iraqi fields, the empirical equations were not used to find the hydrodynamic pressure gradient, but rather the derivation equations only. in this study, the empirical equation (one equation) has been performed to predict the hydrodynamic pressure gradient of five wells .then the optimum mud flow rate can be calculated. tables (1) and (2) show the range of data ( only important data were chosen ) and the special information of wells used for this study respectively also table (3) shows the data used for this study.all data are from saleh[1] . iraqi journal of chemical and petroleum engineering university of baghdad college of engineering hydrodynamic pressure gradient correlation of some iraqi oil wells 36 ijcpe vol.13 no.4 (december 2012) -available online at: www.iasj.net previous investigation chien [2] expressed the below equation of pressure gradient: )()/(1[ )pr( 052.0052.0 2 vsvmdhdp c d pt       d p  …(3) differentiate equation (1) with respect to vm, setting the differential from equal to zero, and then solving it for the optimum annular fluid velocity (vm)opt.chien[2] used four models such as bingham, power-law, casson and robertsonstiff to find the optimum fluid velocity. most of researchers focused upon the relation of rheological models and optimum annular flow rate. h.n. hall and howard thompson [3] show the drilled cuttings velocities computed through estimates of cuttings circulation time from bottom. the observed discontinuity in transport at the transition from laminar to turbulent flow was significant. sifferman, t,r. el.[4].concluded that the cutting transport efficiency increases as fluid velocity increases. also, they found that variables such as particle size, drill pipe rotation, drill pipe eccentricity and drilling rate, at most, only moderate effects on carrying capacity in their experiments. thomas, r.p. el.[5]. there experimental results shows that although increasing rotary speed generally improves particle transport, it more pronounced at lower annular fluid velocities and appears to be negligible at high velocities. newitt, d.m. richarrdson,j.f. and gleddon, b.j. [6] and toda, m. et al [7].concluded that pressure losses due to solids –wall friction, pressure losses due to solids – solids collision and pressure losses due to solids – fluid friction can be neglected compared to the total pressure drop. lummus j. l. [8]. resulted in a better understanding of the effect of drilling variables and their interactions. he defined the optimized drilling as the "mathematical treatment of the most important controllable drilling variables to develop a comprehensive minimum cost drilling program". the variables involved in rotary drilling are classified as alterable or unalterable and the variables selected for mathematical optimization are herein described. the alterable variables: 1. fluid properties such as: fluid density's solid content, viscosity, fluid loss and fluid type. 2. hydraulic fluid system such as: pump pressure, jet velocity, circulating rate and annular velocity 3. weight on bit. 4. rotary speed 5. bit type and bit size. the unalterable variables (uncontrolled) such as: weather, location, rig conditions, corrosive gas, bottom hole temperature, depth, round trip time formation characteristics, hole problems, water availability and crew efficiency. correlation (this study) the following general relation of hydrod-dynamic pressure gradient is assumed: hydrodynamic pressure gradient = f( ρ , pr , qm ) …(4) the chaos of these important parameters is due to their direct effect on hydrodynamic pressure gradient, and these parameters are designed at the beginning of drilling. hydrodynamic pressure gradient  (ρ, pr, 1/qm ) …(5) riyadh hazim fawzi -available online at: www.iasj.net ijcpe vol.13 no.4 (december 2012) 37 table (3) shows data of sixty nine points used to write the following correlation equation in this study by using statistical program. non-linear model will be chosen to develop the following equation: d pbh = a1 + a2*ρ + a3*pr + a4/qm + a5*ρ 2 + a6*pr 2 + a7/qm 2 … (6) where: a1= 1.833331 a2= 0.299532 a3= 0.063143 a4= 0.825984 a5= 0.020372 a6= 0.002062 a7 =187.782992 statistical analysis naji tawfik. and rashid al – salihi, [9] and w.h. aleen, [10]. the relative deviation error in percent from the data:    n i ei n apre 1 1 …(7) where: ei is the relative deviation in percent of an estimated value from the compute value: ,,...2,1100 ni xcal xcalxest pre         …(8) the average absolute percent relative error is given as:    n i pre n aapre 1 1 …(9) the minimum and maximum values to know the range of error for this correlation are given as: pree n i min 1 min   …(10) pree n i max 1 max   …(11) standard deviation (sx) is the measure of the data dispersion around zero deviation as follows: 2 11 1    n i pre n sx …(12) correlation coefficient (r) is the degree of success in reducing the standard deviation as follows:                      n i i n i i xcalx calxestx r 1 2 1 2 2 )( )( 1 …(13) where    n i i calx n x 1 )( 1 …(14) results and discussions fig(1) presents the relation between the calculated hydrodynamic pressure gradient saleh [1] and the estimated hydrodynamic pressure gradient of this study by using eq(6). most of the data points are close to the perfect line 45 o (0.79 rad.). table (4) shows the comparison of average percent relative error between the saleh [1] calculations and this study correlation for the hydrodynamic pressure gradient with very small different between them for all data. the correlation coefficient for this study of eq (6) presents high value of 0.9999 with the lowest value of hydrodynamic pressure gradient correlation of some iraqi oil wells 38 ijcpe vol.13 no.4 (december 2012) -available online at: www.iasj.net standard deviation of 0.9380 as shown in table (5). fig (2) shows the histogram distribution of calculated (saleh [1]) and the correlation value of hydrodynamic pressure gradient. it also shows the behavior similarity of this study and saleh [1]. fig(3)presents the average percent relative error ( apre ) for this study from  3%. it is possible to use a simple computer program to extract the optimum mud flow rate ( optimum qm) . the program can calculate the hydrodynamic pressure gradient (eq(6)) by increasing the mud flow rate (qm) as the input data (suggest data such as 100,150,200,...etc) in the computer program. it is known if mud flow rate is increased, the hydrodynamic pressure gradient decreases. when the hydrodynamic pressure gradient reaches a point which starts to increase or the previous value equal or increase with the present value ( with accuracy such as 1e-4 ), the point that precedes the previous value represents the optimum mud flow rate. conclusions 1. hydrodynamic pressure gradient of five iraqi drilling wells have been estimated from equation (6). this equation has high correlation coefficient of 0.9999. 2. equation (6) can be used for all mud flow rate, mud density and penetration rate instead of using many charts. 3. the importance of equation (6) is to estimate the hydrodynamic pressure gradient by the directly using of the practical field factors. nomenclatures aapre = average absolute percent relative error, (%), eq.(9) apre = average percent relative error, (%), eq. (7) d = total depth of the well, (ft) max e = maximum absolute percent relative error, (%), eq.(11) min e = minimum absolute percent relative f = function j = number of sections along the annulus. l = length, (ft) li = length of the i th section of annulus, (ft) n = number of variables pbh/d = hydrodynamic pressure gradient, (psi/ft) pr = penetration rate, (ft/hr) pre = percent relative error, (%) eq.(8) qm = mud flow rate, gal/min. r = correlation coefficient, eq.(13) sx = standard deviation, eq. (12) vm = average fluid velocity,ft/min. (vm)opt = optimum fluid velocity, ft/min. vs = particle slip velocity, ft/min. x = average value of x exp, eq.(14) x cal = calculated value of x (pbh/d) x est = estimated value of x (pbh/d) ρ = mud density, (ib/gal). ρc = drilled cutting density, (ib/gal).  pt = total pressure drop, (psi). subscripts cal calculated from saleh [1] est estimated from correlation (this study) max maximum min minimum si metric conversion factors atm  1.013 250* e + 05 = pa psi 6.894 757 e + 00 = kp references 1. mohammad midhat saleh (1989). carrying capacity design for riyadh hazim fawzi -available online at: www.iasj.net ijcpe vol.13 no.4 (december 2012) 39 rotary drilling operations.m.sc thesis baghdad university, college of engineering, department of petroleum engineering, iraq. 2. chien, s. (1972). annular velocity for rotary drilling operations.intl. j. rock mech. min. sci. 9, 403-16. 3. h.n. hall, howard thompson, and frank nuss (february 1950). journal of petroleum technology.spe.vol.2.n.2. pages 35-46. 4. sifferman, thomas r., myers, george m., haden, elard l., wahl, harry a.(november 1974). drill cutting transport in full scale vertical annuli. spejournal of petroleum technology. vol.26. n.11. pages1295-1302. 5. thomas, r.p., azar, j.j. and becker, t.e.(september 1982). drillpipe eccentricity effect on drilled cuttings behavior in vertical wellbores .spejournal of petroleum technology. vol.34.n.9. pages 1929-1937. 6. newitt, d.m. richarrdson,j.f. and gleddon, b.j. (1961). hydraulic conveying of solids in vertical pipes.trans. iche.vol.39.pages 93100. 7. toda, m. et al. (july 1969). hydraulic conveying of solids through horizontal and vertical pipes. int1. chem. eng. vol.9.pages 553-560. 8. lummus j. l.(oct-dec 1969). factors to be considered in drilling optimization. spe. journal of canadian petroleum technology. vol.8. n.4. pages 138-146. 9. naji tawfik. and rashid al – salihi, (1989). engineering statistics. baghdad university, college of engineering. iraq: higher education publication. 10. w.h. aleen and co., ltd. (1973). hayslett, h.t., statistics made simple. london. table 1, range of data depth, ft 1325 to 3027 mud density , ib/gal 9.66 to 10.41 penetration rate, ft/hr 6.56 to 24.6 pbh/d , psi/ft 0.45986 to 0.577299 qm (suggestion) , gal/min 100 to 2000 table 2, selected information of wells. saleh[1] well no. 1 2 3 4 5 formation type limestone anhydrite marle &siltstone anhydrite limestone depth, ft 1896 1407 3027 1906 1325 mud density , ib/gal 10.41 9.58 10.41 8.75 9.66 penetration rate, ft/hr 6.56 7.87 24.60 6.56 9.84 applied mud flow rate, gal/min 385 400 570 460 265 hydrodynamic pressure gradient correlation of some iraqi oil wells 40 ijcpe vol.13 no.4 (december 2012) -available online at: www.iasj.net table 3, data used for this study (five drilling wells). saleh[1] case no. qm, gal/min pbh/d, psi/ft ρ, ib/gal pr, ft/hr 1 111.111 0.5553330 11.110 ..5.1 2 111.111 0.5248800 0.5.1 ....1 3 111.111 0.5735020 11.111 21..1 1 111.111 0.4853680 ...51 ..5.1 5 111.111 0.5276230 3...1 0..11 . 151.111 0.5526360 11.110 ..5.1 . 151.111 0.5138320 0.5.1 ....1 . 151.111 0.5690950 11.111 21..1 0 151.111 0.4665940 ...51 ..5.1 11 211.111 0.5513890 11.110 ..5.1 11 211.111 0.5098780 0.5.1 ....1 12 211.111 0.5676160 11.111 21..1 13 211.111 0.4633030 ...51 ..5.1 11 211.111 0.5330560 3...1 0..11 15 251.111 0.5505350 11.111 ..5.1 1. 251.111 0.5078590 0.5.1 ....1 1. 251.111 0.5665440 11.111 21..1 1. 251.111 0.4619740 ...51 ..5.1 10 311.111 0.5500250 11.110 ..5.1 21 311.111 0.5066380 0.5.1 ....1 21 311.111 0.5664550 11.111 21..1 22 311.111 0.4612680 ...51 ..5.1 23 311.111 0.5375840 3...1 0..11 21 111.111 0.5496300 11.110 ..5.1 25 111.111 0.5052400 0.5.1 ....1 2. 111.111 0.5658740 11.111 21..1 2. 111.111 0.4605550 ...51 ..5.1 2. 111.111 0.5469220 3...1 0..11 20 511.111 0.5491470 11.111 ..5.1 31 511.111 0.5044690 0.5.1 ....1 31 511.111 0.5660530 11.111 21..1 32 511.111 0.4602170 ...51 ..5.1 33 511.111 0.5609960 3...1 0..11 31 .11.111 0.5491380 11.110 ..5.1 35 .11.111 0.5039850 0.5.1 ....1 3. .11.111 0.5672710 11.111 21..1 3. .11.111 0.4600370 ...51 ..5.1 3. .11.111 0.5491150 11.111 ..5.1 30 .11.111 0.5036570 0.5.1 ....1 11 .11.111 0.5687570 11.111 21..1 11 .11.111 0.4599380 ...51 ..5.1 12 .11.111 0.5489590 11.111 ..5.1 13 .11.111 0.5034220 0.5.1 ....1 11 .11.111 0.5686420 11.111 21..1 15 .11.111 0.4598860 ...51 ..5.1 riyadh hazim fawzi -available online at: www.iasj.net ijcpe vol.13 no.4 (december 2012) 41 table 3, data use for this study (five drilling wells) (continue). saleh[1] case no. qm, gal/min pbh/d, psi/ft ρ, ib/gal pr, ft/hr 64 099.999 0.5489660 09.609 4.549 64 099.999 0.5032480 0.599 4.949 69 099.999 0.5710700 09.609 06.49 60 099.999 0.4598630 9.459 4.549 59 0999.999 0.5489250 09.609 4.549 50 0999.999 0.5031160 0.599 4.949 50 0999.999 0.5729180 09.609 06.49 53 0999.999 0.4598600 9.459 4.549 56 0059.999 0.5487720 09.609 4.549 55 0059.999 0.5028960 0.599 4.949 54 0059.999 0.5753300 09.609 06.49 54 0059.999 0.4599700 9.459 4.549 59 0599.999 0.5494640 09.600 4.549 50 0599.999 0.5027710 0.599 4.949 49 0599.999 0.5737500 09.609 06.49 40 0599.999 0.4600830 9.459 4.549 40 0459.999 0.5492910 09.609 4.549 43 0459.999 0.5026980 0.599 4.949 46 0459.999 0.5743210 09.609 06.49 45 0459.999 0.4603990 9.459 4.549 44 0999.999 0.5496250 09.609 4.549 44 0999.999 0.5026550 0.599 4.949 68 0999.999 0.5772990 10.410 24.60 69 0999.999 0.4611720 8.750 6.560 hydrodynamic pressure gradient correlation of some iraqi oil wells 42 ijcpe vol.13 no.4 (december 2012) -available online at: www.iasj.net table 4, hydrodynamic pressure gradient estimated correlation for this study case no. calculated hydrodynamic pressure gradient(psi/ft), (saleh,[1]) estimated hydrodynamic pressure gradient(psi/ft), (this study) deviation % estimated hydrodynamic pressure gradient (apre) pbh/d(estimated) pbh/d(calculated) (psi/ft) 0 0.555333 0.557735 0.432453 0.002402 0 0.524880 0.514002 2.072468 0.010878 3 0.573502 0.578067 0.796000 0.004565 6 0.485368 0.470196 3.125784 0.015172 5 0.527623 0.547815 3.826934 0.020192 4 0.552636 0.552088 0.099111 0.000548 4 0.513832 0.508356 1.065765 0.005476 9 0.569095 0.572421 0.584402 0.003326 0 0.466594 0.464550 0.438031 0.002044 09 0.551389 0.550379 0.183233 0.001010 00 0.509878 0.506646 0.633847 0.003232 00 0.567616 0.570711 0.545298 0.003095 03 0.463303 0.462841 0.099812 0.000462 06 0.533056 0.540459 1.388767 0.007403 05 0.550535 0.549709 0.149992 0.000826 04 0.507859 0.505977 0.370630 0.001882 04 0.566544 0.570042 0.617386 0.003498 09 0.461974 0.462171 0.042672 0.000197 00 0.550025 0.549411 0.111554 0.000614 09 0.506638 0.505679 0.189306 0.000959 00 0.566455 0.569744 0.580620 0.003289 00 0.461268 0.461873 0.131229 0.000605 03 0.537584 0.539492 0.354857 0.001908 06 0.549630 0.549206 0.077109 0.000424 05 0.505240 0.505474 0.046247 0.000234 04 0.565874 0.569539 0.647619 0.003665 04 0.460555 0.461668 0.241681 0.001113 09 0.546922 0.539286 1.396101 0.007636 00 0.549147 0.549172 0.004575 0.000025 39 0.504469 0.505440 0.192400 0.000971 30 0.566053 0.569505 0.609774 0.003452 30 0.460217 0.461634 0.307901 0.001417 33 0.560996 0.539252 3.875901 0.021744 36 0.549138 0.549187 0.008838 0.000049 35 0.503985 0.505454 0.291478 0.001469 34 0.567271 0.569519 0.396293 0.002248 34 0.460037 0.461648 0.350281 0.001611 39 0.549115 0.549215 0.018212 0.000100 30 0.503657 0.505482 0.362445 0.001825 69 0.568757 0.569548 0.138992 0.000791 60 0.459938 0.461677 0.378072 0.001739 riyadh hazim fawzi -available online at: www.iasj.net ijcpe vol.13 no.4 (december 2012) 43 table 5, statistical accuracy of the hydrodynamic pressure gradient of this study table (5) statistical accuracy of the hydrodynamic pressure gradient of this study. average relative error , % 0.0210 average absolute relative error , % 0.5579 minimum absolute relative error , % 0.0046 maximum absolute relative error, % 3.8759 standard deviation, % 0.9380 correlation coefficient (r) 0.9999 table 4, hydrodynamic pressure gradient estimated correlation for this study (continue) case no. calculated hydrodynamic pressure gradient(psi/ft) from saleh, [1] estimated hydrodynamic pressure gradient(psi/ft) (this study deviation % estimated hydrodynamic pressure gradient (apre) pbh/d(estimated) pbh/d(calculated) psi/ft 12 0.548959 0.549246 0.052335 0.000287 13 0.503422 0.505514 0.415512 0.002092 11 0.568642 0.569579 0.164747 0.000937 15 0.459886 0.461708 0.396227 0.001822 1. 0.548966 0.549277 0.056567 0.000311 1. 0.503248 0.505544 0.456238 0.002296 1. 0.571070 0.569609 0.255826 0.001461 10 0.459863 0.461738 0.407823 0.001875 51 0.548925 0.549304 0.069123 0.000379 51 0.503116 0.505572 0.488140 0.002456 52 0.572918 0.569637 0.572690 0.003281 53 0.459860 0.461766 0.414544 0.001906 51 0.548772 0.549363 0.107688 0.000591 55 0.502896 0.505630 0.543739 0.002734 5. 0.575330 0.569695 0.979353 0.005635 5. 0.459970 0.461825 0.403256 0.001855 5. 0.549464 0.549408 0.010206 0.000056 50 0.502771 0.505675 0.577679 0.002904 .1 0.573750 0.569740 0.698833 0.004010 .1 0.460083 0.461870 0.388368 0.001787 .2 0.549291 0.549443 0.027662 0.000152 .3 0.502698 0.505710 0.599251 0.003012 .1 0.574321 0.569775 0.791462 0.004546 .5 0.460399 0.461905 0.327073 0.001506 .. 0.549625 0.549471 0.028055 0.000154 .. 0.502655 0.505738 0.613399 0.003083 68 0.577299 0.569803 -1.298404 0.007496 69 0.461172 0.461933 0.164949 0.000761 hydrodynamic pressure gradient correlation of some iraqi oil wells 44 ijcpe vol.13 no.4 (december 2012) -available online at: www.iasj.net fig. 1, cross plot of hydrodynamic pressure gradient, (psi/ft) saleh[1] saleh[1] riyadh 0.44 0.46 0.48 0.50 0.52 0.54 0.56 0.58 hydrodynami c pre ssure gradi e nt (psi /ft) fig(2):histogram distribution of calculated and correlation values of hydrodynamic pressure gradient. 0 2 4 6 8 10 12 14 16 n o o f o b s hi stogram .x 6v*69c)fig(2): histogram distribution of calculated and correlation values of hydrodynamic pressure gradient(محمد مدحت النهائي تعديل) fig(1):cross plot of hydrodynamic pressure gradient, (psi/ft) 0.45 0.48 0.51 0.54 0.57 0.60 0.45 0.48 0.51 0.54 0.57 0.6 calculate d hydrodynamic pre s s ure gradie nt, (ps i/ft) sale h[1] e st im at ed h yd ro dy na m ic pr es su re g ra di en t, (p si /ft ) (t hi s st ud y) fig. 2, histogram distribution of calculated and correlation values of hydrodynamic pressure gradient riyadh hazim fawzi -available online at: www.iasj.net ijcpe vol.13 no.4 (december 2012) 45 average relative error % fi g(3):error di s tri bu ti on of h ydrodyn am i c pre s s u re gradi e n t corre l ati on (th i s s tu dy) f r e q u e n c y <= -4 (-4,-3] (-3,-2] (-2,-1] (-1,0] (0,1] (1,2] (2,3] (3,4] > 4 0% 5% 10% 15% 20% 25% 30% 35% 40% 45% 50% 55% 60% 65% fig. 3, error distribution of hydrodynamic pressure gradient correlation (this study) available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.23 no.3 (september 2022) 75 – 83 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: ali k. al-delfi, email: ali.hashim2008m@coeng.uobaghdad.edu.iq, name: faleh h. m. al-mahdawi, email: dr.f.h.m.almahdawi@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. polyacrylamide polymer gel systems for conformance control technology: a review ali k. al-delfi and faleh h. m. al-mahdawi petroleum engineering department, university of baghdad abstract low oil extraction and early high water production are caused in part by reservoir heterogeneity. huge quantities of water production are prevalent issues that happen in older reservoirs. polyacrylamide polymer gel systems have been frequently employed as plugging agents in heterogeneous reservoirs to regulate water output and increase sweep efficiency. polyacrylamide polymer gel systems are classified into three classes depending on their composition and application conditions, which are in-situ monomer gel, in-situ polymer gel, and preformed particle gel (ppg). this paper gives a comprehensive review of ppg’s status, preparation, and mechanisms. many sorts of ppgs are categorized, for example, millimeter-sized preformed particle gels, microgels, ph-sensitive cross-linked polymers, swelling polymer grains, and bright water®. in addition to this, the most important factors to consider while assessing gel performance, such as swelling capacity, ppg injectivity, and plugging efficiency, are studied carefully. not only are the design considerations and field application of ppg mentioned, but also the advantages of ppg are demonstrated. gels have been used in around 10,000 wells worldwide to reduce the fractures permeability or super-high permeability channels during water and polymer floods. keywords: polyacrylamide, in-situ gel, preformed particle gel, conformance control received on 15/06/2022, accepted on 06/07/2022, published on 30/09/2022 https://doi.org/10.31699/ijcpe.2022.3.10 1introduction as the rate of new reservoir discoveries slows, enhanced oil recovery (eor) methods for older oilfields become more important. eor techniques often include the injection of substances not found inside the reservoir, like foams, surfactants, polymers, solvents, etc. the reservoir's heterogeneity is a significant factor in determining poor oil recovery and rapid extra water cut. a lot of mature reservoirs have cracks or high-permeability pathways that were caused by flooding. these are called thief zones [1]. waterflooding has been used as a secondary recovery strategy for many decades. however, owing to long-term waterflooding operations throughout numerous fields, a huge permeability difference, fractures presence, injected water be apt to inflow along the slightest resistive channels, resulting in low sweep efficiency and the loss of significant oil amounts. the effects of this issue contain a quick drop in oil production, the requirement for separation of water and oil, more money spent on pumping, treating, and disposing of water, and early well abandonment[2]. the yearly cost of separating, handling, and disposing of undesirable water production is over $50 billion[3]. conformance control is described as the use of techniques within reservoirs and wellbores which minimize unexpected water production and maximize hydrocarbon oil recovery. it accomplishes these objectives by decreasing or sealing the water generated by high permeability formations, fractures, and fracture-like structures. to solve excess water production issues, three primary conformance control techniques are available: mechanical, completion, and chemical solutions[4]. numerous solutions have been used to address the issues of excessive water production and eor methods. they include flooding with polymers, flooding with alkaline surfactants, foam flooding, etc. polyacrylamide (pam) polymer gel therapy is a popular and cost-effective approach among them. gels have found widespread usage as fluid-flow blocking agents in the oilfield because they are often a very cost-effective blocking and/or permeability-reducing solution for conformance control applications. a more traditional simplification of gel is as "a jelly-like material generated when a colloidal solution coagulates into a semisolid form." gel is a word used in the current oil industry and technical literature to refer to the elasticity and semisolid substance formed by chemically crosslinking water soluble polymers in an aqueous solution. gels are often manufactured using cheap commodity polymers[5]. gel treatment is a popular eor technique that is useful for enhancing the recovery of oil in mature reservoirs having fractures or fracture-like structures. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:ali.hashim2008m@coeng.uobaghdad.edu.iq mailto:dr.f.h.m.almahdawi@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2022.3.10 a. k. al-delfi and f. h. m. al-mahdawi / iraqi journal of chemical and petroleum engineering 23,3 (2022) 75 83 76 the basic function behind gel treatment is that it can plug or significantly reduce the permeability of the fractures and the permeability contrast within the zones, which reduces the water flow preference through the fractures and water channelling. the performances of the water sweep and oil recovery are therefore improved. there are three types of polymer gel technology, which are in-situ monomer gel, in-situ polymer gel, and preformed particle gels. studies reveal that ppg is environmentally friendly, strong and small-controllable, stable over longer durations, and also very likely able to overcome several limitations inherent in in-situ gelling. reservoir minerals and salinity of the formation water have no effect on its thermostabilization. 2types of polymer gel treatment gels are often categorised according to their formulation, properties, and intended use. there are three types of polymer gel technology, which are in-situ monomer gel, in-situ polymer gel, and preformed particle gels. 2.1. in-situ monomer gel for conformance control, several older applications employed an acrylamide monomer system which polymerized in-situ. the monomer plus crosslinker mixture exhibited an initial viscosity equivalent to water when brought into formation with 4 percent to 10 percent total dissolved particles (i.e., 1–1.3 cp). it might penetrate all regions in the formation's in-depth regions because of its initial low viscosity. however, controlling monomer gelation at high temperature operation conditions was challenging, since monomer gelation is a free-radical started fast process. to avoid early gelation, a retardant was frequently used[1]. 2.2. in-situ polymer gel in-situ gel operation is a widely utilized technique of conformity control in the oil industry. in the 1970s, phillips co. (now conocophillips) used partly hydrolyzed polyacrylamides (hpam) and aluminum citrate to create the first in-situ polymer gels[6]. since then, interest in insitu polymer gel solutions has increased. in-situ gel treatments are crosslinked polymers made up of polymers, crosslinkers, as well as additives. the crosslinking agent attaches itself to two neighbouring polymer molecules, chemically or physically, connecting them together. a gelant is the liquid form of this compound. the gallant is injected into the zone through an in-situ mechanism, and the gel is formed under reservoir conditions. under different circumstances, including rising temperature and changing ph, the gelant may crosslink and create a gel. gel strength may be controlled by both the composition of the gelant and the surrounding environment[7]. the researchers noted that although the strength factor of injected gelant is often significantly greater than that of injected polymer, in-situ gel field testing revealed that this approach may sometimes result in increased damage to small permeability un-swept oil regions. while in-situ gel system is cost-effective and thus appealing, they do have some inherent disadvantages, including restricted control over time of gelation, challenges dominant the stabilization and resistance of the composed gel, adsorption of materials on the surface of rock, reactions with water of formation, and mitigation and dissolution of polymer throughout reservoir[8]. polymer gels are divided into bulk and weak gels based on their variety of gel strengths, which is indicated by viscosity. the viscosity of bulk gels is often more than 30000 cp, but the viscosity of weak gels is between 100 and 10000 cp[9]. 2.3. preformed particle gel preformed particle gel (ppg) was introduced in 1996 by the research institute of petroleum exploration and development (riped) of petrochina as a novel sort of conformance control technology. for conformance control reasons, many different types of ppgs have already been established recently. typically, preformed particle gels are prepared using a monomer like acrylamide, a crosslinker, an initiator, and other ingredients. the gel is manufactured in ground facilities, dried, crushed into tiny particles, and then sieved to pick up the particles of the desired size. ppgs vary in size from micrometres to centimetres[10]. preformed gels are created on the surface prior to injection and are injected into the reservoir as particulates; no gelation happens in the reservoir. ppg is capable of absorbing a considerable amount of an aqueous mixture; the polymers should be just weakly cross linked to allow the polymer chains to grow in a vast area. ppgs may expand to hundreds of times their volume in liquids, making it difficult to discharge the absorbed liquids under pressure. after swell, the ppg is pumped into the formation to plug or minimize the permeability of fractures, fracture-like channels, or large permeability zones[11]. all prepared particle gels utilized for conformance control are members of the superabsorbent polymer family (sap). sap is a three-dimensional network of cross-linked polymer series which have the capability to absorb or ingest more than ten times their mass in water or aqueous solutions[1]. the first effective field use of ppg occurred in 1999 at the zhongyuan oilfield. ppg has been employed successfully in china for over 5,000 wells to minimize water cut or polymer output in mature waterflood zones[11]. a. k. al-delfi and f. h. m. al-mahdawi / iraqi journal of chemical and petroleum engineering 23,3 (2022) 75 83 77 apreparation of preformed particle gel the processes for synthesizing ppg in the laboratory are described by bai. et al. [10] as below:  make an aqueous mixture that has acrylamide, a crosslinker, an initiator, with other ingredients based on a specific formula.  at a certain temperature, crosslink the solution to create a bulk gel.  divide the bulk gel to tiny pieces and dry at 70°c  depending on the field application requirements, mechanically grind the dried gel fragments into micrometer-sized or millimeter-sized particles.  sieve the particles until the required size is achieved. bmechanisms of ppg treatment gel treatment is a common eor method that is useful for enhancing the recovery of oil in mature reservoirs having fractures or fracture-like structures. the principle of gel treatment is that it may plug or greatly decrease the fracture permeability and minimize the permeability contrast inside the zones; consequently, the water flow preference via the fractures is lessened and water channeling is minimized. as a consequence, the water sweep performance and recovery of oil are enhanced. the use of particle gel improves sweep performance in heterogeneous reservoirs. while typical polymer flooding may also increase sweep competence, the difference between polymer flooding and gel therapy and is significant. polymer solutions are designed to perforate deeply into unswept zones or inadequately swept zones with low-permeability, whilst gelants inject into areas with high-permeability and avoided in low-permeability zones[12]. by way of explanation, the polymer acts like as an agent for mobility control while the ppg acts as a blocking agent. ppg is synthesized at the surface facility and pumped into forms as a single component. these swelling particles vary significantly from rigid particulates in that they are flexible and deformable, allowing them to access via throats of formation pore which are far minimal than themselves. as a result, they may deform and enter through huge channels or cracks located deep inside the zone of high permeability. if a small quantity of ppg is applied near the wellbore, the following water will skip the pumped gel and revert to earlier water routes in the zones with high permeability, indicating that the curing has no influence on production of water and hydrocarbon. a large quantity of ppg, particularly if it can be deployed among wells, is far more efficient in sweeping up more oil [13]. the upper part of fig. 1 illustrates the effect of pumping a small quantity of ppg gel which will be located near wellbore and lead to block the beginning of a high permeability zone which result the following water will skip the pumped gel and revert to earlier water routes in the zones with high permeability. on the other hand, the lower part of fig. 1 explains that a big quantity of injected ppg gel has a more efficient in sweeping up more oil since the waterflooding will flow through the low permeability zones which have an unswept oil. fig. 1. mechanism of ppg treatment [13] ctypes of ppg various kinds of ppgs have diverse particulate sizes based on their application, swelling time, and swelling ratio. there are micro to millimeter-sized ppg[10], microgels[14], ph-sensitive cross-linked polymers[15], swelling polymer grains[16] , and bright water®[17]. microgels, ph-sensitive crosslinked polymers, swelling polymers, and bright water are examples of small particle gels which they have sizes ranging from nano to micrometer that can be utilised to decrese production of water and control profiles in heterogeneous reservoir which have permeability less than a darcy. the techniques contain altering relative permeability, and blocking big pores[18]. millimeter-sized particle gels are often used in fractures or channels resembling fractures with permeability greater than a few darcies. in ppg treatment, the principal strategy of conformance control is to partly or completely block the high permeability zone. extensive laboratory testing has shown that millimeter-sized particles cannot be transported via porous media under typical reservoir pressure gradients due to the particle size being too big relative to the matrix pore throat. as a result, the trapped particles agglomerate and create a form of gel cake at the surface of rock, increasing the pressure gradient significantly. this pressure gradient will surpass threshold pressure necessary for particulate extrusion via the open[18]. dproperties of ppg when exposed to water, ppg often swells dozens to hundreds of times its initial size. particles become flexible and deformable upon swelling. the swollen particles are injected into the desired medium at concentrations ranging from 1000 to 20,000 parts per million (ppm) and either block or decrease the permeability of highly permeable media such as fractures and channels[19]. a. k. al-delfi and f. h. m. al-mahdawi / iraqi journal of chemical and petroleum engineering 23,3 (2022) 75 83 78 according to researchers' laboratory experiments, the primary factors for assessing gel performance swelling capacity, injectivity of ppg, and plugging efficiency  swelling capacity of ppg swelling capacity refers to the amount of water or brine that a certain quantity of dry ppg can absorb. the following two techniques for determining swelling capacity have been published in the literature:  volumetric method preformed particle gel with the required concentration is mixed in the proper brine which made with a 100 ml gradient colorimetric tube. after that, the ppg suspension is placed in bath of water that has been preheated to the proper temperature. at uniform time periods, the volume of swollen ppg is measured until its alteration is minimal. the swelling proportion during any point in time can be computed using the equation below[20]: sr = vs vd x 100 (1) where: sr: swelling ratio (cc/cc) vs: the ppg volume after swelling (cc) vd: the initial dry volume of ppg (cc)  gravimetric method for the specified time period, a weighed amount of dry ppg is immersed in the specified amount of water. following that, a paper filter is used to separate the residual water from the swollen ppg. then, the ppg net weight is calculated. the below equation is used to measure the ration of swelling[21]: 𝑆𝑅 = 𝑀𝑠 − 𝑀𝑑 𝑀𝑑 𝑥 100 (2) where: ms: the weight after swelling md: the weight of dried ppg the volumetric method technique isn't a trustworthy measurement method. because of the water amount placed between the gels particulates are comprised in the total volume, the gravimetric method technique eliminates this inaccuracy, resulting in a more efficient method than the volumetric method.  injectivity of ppg the injectivity of a ppg is utilised to determine if ppg can pass via the core or sandpack or to determine the complexity of injected ppg. ppg injectivity equals the steady flow rate divided by the steady injection pressure in the laboratory[22]. coste et al. explained that particles might pass through pore constraints in three ways: deforming and passing, shrinking and passing, or breaking and passing[23]. in addition to this, bai et al. was found that when ppg moved across porous surfaces, there were three different transport patterns: pass, broken and pass, and plug[24]. when pressure gradient is larger than threshold pressure, ppg may move via a narrower pore throat size. the threshold pressure wanted to move a particle throughout a porous media is governed by the particulate and pore throat diameter proportion, the stiffness of the swelling ppg, and the porous medium structure[24].  plugging efficiency of ppg the performance of gel therapy focuses greatly on the capacity of the gel to minimize the formations permeability or fractures[25]. plugging efficiency and water residual resistance factor are typically employed to assess ppg implementation in single core or sandpack blocking competence trials. the plugging efficiency is known as the proportional decrease in permeability after ppg treatment. water residual resistance factor is a ratio of water permeability before and after ppg treatment. frrw is calculated in the experiment by dividing the pressure drop of the water injection after ppg treatment and pressure of the injected water before gel therapy. 𝐹𝑟𝑟𝑤 = 𝑃𝑟𝑒𝑠𝑠𝑢𝑟𝑒 𝑑𝑟𝑜𝑝 𝑎𝑓𝑡𝑒𝑟 𝑡𝑟𝑒𝑎𝑡𝑚𝑒𝑛𝑡 𝑃𝑟𝑒𝑠𝑠𝑢𝑟𝑒 𝑑𝑟𝑜𝑝 𝑏𝑒𝑓𝑜𝑟𝑒 𝑡𝑟𝑒𝑎𝑡𝑚𝑒𝑛𝑡 (4) frrw = kb ka (5) where: frrw is water residual resistance factor kb is permeability of water before treatment ka is the permeability of water after treatment the relationship between frrw and plugging efficiency is 𝐸 = [1 − 1 𝐹𝑟𝑟𝑤 ] ∗ 100 (6) it is preferable to use frrw to indicate the decrease in water permeability caused by gel[22]. plugging efficiency rises with increasing ppg strength, size, and concentration in the sandpack model[26]. e. environmental parameters effect’s on ppg properties the status of the reservoir into which ppg will be injected has an important effect on the properties of the ppg. the environmental parameters such as temperature of the reservoir, salinity of the formation brine, and ph of the formation brine are the main parameters that affect the pumped ppg.  temperature when temperature increases by more than 80 c, the swelling capacity of the preformed particle gel grows[10]. temperature may have an effect on a ppg treatment's thermostability. ppgs are normally thermally stable for more than a year in field applications when used under reservoir conditions[22]. a. k. al-delfi and f. h. m. al-mahdawi / iraqi journal of chemical and petroleum engineering 23,3 (2022) 75 83 79  salinity ppg mixed with brine with low salinity exhibited a lower strength and a higher ratio of swelling than gel prepared brine with high salinity [10]. ppgs have great salt resistance and are hence suitable for usage in highsalinity reservoirs. ppgs are more thermostable in high salinity water because of increased crosslinker density, which results in a decreased swelling ratio, which strengthens the particles. furthermore, increasing gel strength has another benefit: it improves the efficiency of plugging[27].  ph at low ph values (less than 7), the release of proton ions protects negatively charged groups from the electrostatic repulsive force. as a result, raising the ph to almost neutral circumstances, results in a rise in the capacity of ppg swelling. additionally, elevating the ph to an alkaline environment has no discernible effect on swelling capacity[10]. f. ppg treatment design consideration considerations for the design of the ppg treatment process include injection equipment, injection procedure, and injection parameters. ppg treatments need simple injection facilities since these gels typically contain just one ingredient throughout the process of injection, and bullhead is often employed to achieve selective permeation of gel particulates. ppg pumping is a multistage procedure that includes a gradual growth or reduction in the ppg size particle and a ppg concentration. the size of particle and concentration of ppg suspension determined in the initial step are significant because they serve as a baseline for curing planning. ppg particulate size, volume of injection, and concentration of ppg suspension are all injection parameters.  particle size suitable particle size selection is critical for ppg therapy efficacy. the particle size of ppg must be tiny sufficient to penetrate and pass through the zone, but large adequate to fill the channels with high permeability zones. field operators frequently depend on ppgs' stiffness for granted and use particulate sizes up to 1/3 the size of the pore throat. indeed, ppgs vary significantly from stiff particles in that they expand when exposed to water or brine, and the swelled gel particles are flexible, allowing them to flow smoothly down a pore throat[22]. according to one experimental study, ppgs can permeate through pore throats 0.175 times the diameter of the swollen ppg[24]. in the field operations, there are now two basic kinds of injection processes that are widely used in terms of particle size. the first form involves initially injecting big particles, followed by many stages progressively rising from tiny to large particles according to the reaction of injection pressure. the purpose of the first injection of big particulates is to build gel cakes on the faces of zones with low-permeability, preventing subsequent tiny particles from accessing and harming un-swept oil regions[10]. anyway, if the starting particulate size is selected incorrectly, the injection pressure may quickly rise to reach formation fracture pressure, which could cause fractures inside the formation. the second method of injecting ppg is to use numerous stages to inject particles straight from tiny to big sizes. because this approach allows the front of the ppg slug to enter deeply and avoids the need to inject gel breaker after therapy, over 90% of injection operations use the latter technique[11].  injection volume a significant volume of gel injection is critical for increasing treatment efficiency on both a technical and economic level, most notably in terms of incremental oil recovery. numerous approaches were explored to determine the appropriate volume of ppgs to inject. depending on the treatment radius, some operators like to calculate the volume of injection[28]. it is also thought that fracture-like channels with high permeability are found in most of the wells that are treated. this means that the flow geometry may be linear rather than radial[12].  ppg suspension concentration when the quantity of gel is constant, it may be pumped through a huge slug volume with a low ppg concentration or a little slug volume with a big ppg concentration. usually, it is preferable because it permits particles to proceed freely and penetrate greater into the zone, while high ppg concentration tend to constrict particulates around the wellbore[22]. g. advantages of ppg ppgs have gained widespread acceptance and increased operator usage because of their distinct benefits over traditional bulk gel systems, which include the following:  they are synthesized before formation contact, which eliminates many disadvantages associated with in-situ gelation systems, including uncontrolled gelation periods, fluctuations in gelation owing to shear degradation, and gelant changes produced by interaction with reservoir materials and fluids.  they have a regulated strength and size, are environmentally acceptable, and are stable in nearly all reservoir elements as well as formation water salinity. a. k. al-delfi and f. h. m. al-mahdawi / iraqi journal of chemical and petroleum engineering 23,3 (2022) 75 83 80  they have a preference for entering fractures or fracture-feature channels whilst reducing gel penetration in un-swept regions.  they typically contain just one component upon injection, simplifying the procedure of treating ppgs compared to regular in situ gels.  unlike typical in situ gels, which are readily impacted by the salinity of the produced water, ppgs may be created using produced water without affecting the gel's stability, therefore conserving freshwater and safeguarding the environment[29].  when ppg is exposed to water, it can expand several times its original size, but when swelled particle gels are submerged in oil, the size of the gel may decrease to less than half of its initial volume. this feature is extremely advantageous for reservoirs with remaining oil production potential since the shrinking of the particle volume enables the oil to more easily breakthrough[30]. h. field applications of ppgs petrochina started using ppgs for conformity control in 1997. between 1997 and 2013, approximately 4,000 wells in most of china's oilfields were injected with ppgs or ppgs in combination with other gels, involving sandstone reservoirs and carbonate reservoirs with a temperature range and formation salinities[18] ppgs were used at the zhongyuan oilfield in a highsalinity, high temperature reservoir since in-situ gel was not practicable under these difficult circumstances. for many years, the sandstone reservoirs had been flooded, and the issues they faced were quick connection between injection and production wells as well as severe vertical heterogeneity. the ppg application was successful, and it became the principal means of compliance improvement in this oilfield[18]. the shengli oilfield, which is located in china, produces an enormous amount of sand, which was treated with ppg. in 1999, two wells in the shangdian reservoir were treated using ppgs. the shangdian reservoir is a sandstone reservoir with faulted blocks, unconsolidated sand, and a lot of salinity, making it an unsuitable option for traditional gel treatments. following the treatment, profile surveys showed that both vertical fluid distribution and extra oil production had gotten better[18]. ppgs have been used in the usa since the early 1990s, although only a few outcomes are publicly available. ppgs have been employed at west texas's anton irish field. this carbonate reservoir deposit was subjected to a co2 flooding operation beginning in 1997. however, fast leakage of co2 and water via conduits prompted the operators to investigate other conformity control techniques. following numerous fruitless efforts, ppgs were employed to cover the conduits and inhibit co2 and water cycling, resulting in lower co2 and water generation and increased incremental production of oil. this demonstrates that the gels were successful in filling the reservoir's voids[31]. a case study was done on the ppgs utilised in the kelly-snyder field in scurry county, texas, where preformed particle gels up to 6 mm were effectively injected into numerous wells to address their short circuits and regulate co2 production. this application made the injection pattern better, which led to less co2 being released and more oil being produced[32]. 3conclusion polyacrylamide polymer gel had a considerable influence on water shut-off and profile control operations, the plugging of open wellbores, zone or well abandonment, and other applications. there are three types of gel treatments that are classified in this paper. the most dominant type is ppg since it has distinct benefits over traditional bulk gel systems, such as controlling gelation time, taking place at the surface before injection, containing just one component upon injection, and being environmentally friendly. according to the following process, ppg is made by: creating bulk gel, separating the gel's particles, drying the sliced materials. the dry particles are ground, then the particles are sieved to the required size. mechanisms of ppg treatment include the deforming and entering of ppg through huge channels or cracks located deep inside the zone of high permeability to block these regions and allow water to sweep the oil in the low permeability zones. the swilling capacity of ppg is calculated based on two methods, which are the volumetric technique and the gravimetric method. the gravimetric method is a more efficient method than the volumetric method. the residual resistance factor is calculated in order to determine the plugging efficiency of the used gel. in most situations, swelling ration of gel grows with rising temperature (below 100°c), lowering salinity, and growing ph. in addition, when sr rises, the gel strength reduces. the findings of ppg treatment experiments reveal that there is an optimal ppg size for efficiently plugging the high-permeable area while causing the least amount of harm to the low-permeable area. this ideal size varies from one type of ppg to the next. finally, around 10,000 wells have employed gels successfully to decrease super-high permeability channels or fracture permeability during water and polymer floods. nomenclature e plugging efficiency eor enhanced oil recovery frrw water residual resistance factor hpam partly hydrolyzed polyacrylamide ka permeability of water after treatment kb permeability of water before treatment md weight of dried ppg ms ppg weight after swelling pam polyacrylamide sr swelling ratio vd initial dry volume of ppg vs ppg volume after swelling a. k. al-delfi and f. h. m. al-mahdawi / iraqi journal of chemical and petroleum engineering 23,3 (2022) 75 83 81 references [1] b. bai, j. zhou, and m. yin, “a comprehensive review of polyacrylamide polymer gels for conformance control,” pet. explor. dev., vol. 42, no. 4, pp. 525–532, 2015, doi: 10.1016/s18763804(15)30045-8. [2] j. leng, m. wei, and b. bai, “review of transport mechanisms and numerical simulation studies of preformed particle gel for conformance control,” j. pet. sci. eng., vol. 206, no. june, p. 109051, 2021, doi: 10.1016/j.petrol.2021.109051. [3] f. hill, s. monroe, and r. mohanan, “water management an increasing trend in the oil and gas industry,” spe/eage eur. unconv. resour. conf. exhib., pp. 918–922, 2012, doi: 10.2118/154720-ms. [4] y. liu, b. bai, and p. j. shuler, “application and development of chemical-based conformance control treatments in china oil fields,” spe/doe symp. improv. oil recover., vol. 1, pp. 434–443, 2006, doi: 10.2523/99641-ms. [5] r. d. sydansk and g. p. southwell, “more than 12 years of experience with a successful conformancecontrol polymer gel technology,” spe west. reg. meet. proc., 2000, doi: 10.2118/62561-ms. [6] j. w. g. r. b. needham, c. b. threlkeld, “control of water mobility using polymers and multivalent cations,” spe offshore technol. conf., 1974. [7] a. imqam, “particle gel propagation and blocking behavior through high permeability streaks and fractures,” missouri university of science and technology, 2015. [8] l. yu, q. sang, and m. dong, “enhanced oil recovery ability of branched preformed particle gel in heterogeneous reservoirs,” oil gas sci. technol., vol. 73, 2018, doi: 10.2516/ogst/2018062. [9] d. zhu, b. bai, and j. hou, “polymer gel systems for water management in high-temperature petroleum reservoirs: a chemical review,” energy and fuels, vol. 31, no. 12, pp. 13063–13087, 2017, doi: 10.1021/acs.energyfuels.7b02897. [10] b. bai, l. li, y. liu, z. wang, and h. liu, “preformed particle gel for conformance control: factors affecting its properties and applications,” spe/doe symp. improv. oil recover., no. june 2006, pp. 17–21, 2004, doi: 10.2118/89389-ms. [11] b. bai, f. huang, y. liu, r. s. seright, and y. wang, “case study on preformed particle gel for indepth fluid diversion,” proc. spe symp. improv. oil recover., vol. 3, pp. 1438–1455, 2008, doi: 10.2118/113997-ms. [12] r. s. seright and j. lang, “a survey of field applications of gel treatments for water shutoff,” proc. permian basin oil gas recover. conf., pp. 221–231, 1994, doi: 10.2523/26991-ms. [13] y. liu, b. bai, and y. wang, “applied technologies and prospects of conformance control treatments in china,” oil gas sci. technol., vol. 65, no. 6, pp. 859–878, 2010, doi: 10.2516/ogst/2009057. [14] a. zaitoun et al., “using microgels to shut off water in a gas storage well,” spe int. symp. oilf. chem., no. 1, pp. 221–228, 2007, doi: 10.2118/106042-ms. [15] c. huh, s. k. choi, and m. m. sharma, “a rheological model for ph-sensitive ionic polymer solutions for optimal mobility-control applications,” spe annu. tech. conf. exhib., pp. 1–13, 2005, doi: 10.2523/96914-ms. [16] i. abbasy, j. vasquez, l. eoff, and d. dalrymple, “laboratory evaluation of water-swellable materials for fracture shutoff,” spe symp. improv. oil recover., vol. 1, no. hall 1963, pp. 324–337, 2008, doi: 10.2118/111492-ms. [17] h. frampton, j. c. morgan, s. k. cheung, l. munson, k. t. chang, and d. williams, “development of a novel waterflood conformance control system,” spe symp. improv. oil recover., vol. 2004-april, 2004, doi: 10.2118/89391-ms. [18] b. bai, m. wei, and y. liu, “field and lab experience with a successful preformed particle gel conformance control technology,” spe prod. oper. symp., pp. 506–522, 2013, doi: 10.2118/164511-ms. [19] a. imqam, a. goudarzi, m. delshad, and b. bai, “development of a mechanistic numerical simulator for preformed particle gel applications in noncrossflow heterogeneous reservoirs,” spe annu. tech. conf. exhib., vol. 2015-janua, pp. 4828–4847, 2015, doi: 10.2118/175058-ms. [20] w. kang et al., “the effect of stepwise increasing of water injection rates on enhanced oil recovery after preformed particle gel treatment,” j. pet. sci. eng., vol. 182, no. june, p. 106239, 2019, doi: 10.1016/j.petrol.2019.106239. [21] h. r. saghafi, m. a. emadi, a. farasat, m. arabloo, and a. naderifar, “performance evaluation of optimized preformed particle gel (ppg) in porous media,” chem. eng. res. des., vol. 112, pp. 175–189, 2016, doi: 10.1016/j.cherd.2016.06.004. [22] y. qiu, “data analysis and application guidelines of particle gel treatments,” missouri university of science and technology, 2017. [23] j.-p. coste et al., “in-depth fluid diversion by pre-gelled particles. laboratory study and pilot testing.,” spe/doe improv. oil recover. symp., 2007, doi: 10.2523/59362-ms. [24] b. bai, y. liu, j. p. coste, and l. li, “preformed particle gel for conformance control: transport mechanism through porous media,” spe symp. improv. oil recover., vol. 2004-april, 2004, doi: 10.2523/89468-ms. [25] r. s. seright, “gel treatments for reducing channeling in naturally fractured reservoirs,” spe prod. facil., vol. 14, no. 4, pp. 269–276, 1999, doi: 10.2118/59095-pa. [26] a. imqam, b. bai, and m. delshad, “preformed particle gel propagation through super-k permeability sand,” spe/iatmi asia pacific oil gas conf. exhib., 2015. https://www.sciencedirect.com/science/article/pii/s1876380415300458 https://www.sciencedirect.com/science/article/pii/s1876380415300458 https://www.sciencedirect.com/science/article/pii/s1876380415300458 https://www.sciencedirect.com/science/article/pii/s1876380415300458 https://www.sciencedirect.com/science/article/pii/s1876380415300458 https://www.sciencedirect.com/science/article/pii/s0920410521007087 https://www.sciencedirect.com/science/article/pii/s0920410521007087 https://www.sciencedirect.com/science/article/pii/s0920410521007087 https://www.sciencedirect.com/science/article/pii/s0920410521007087 https://www.sciencedirect.com/science/article/pii/s0920410521007087 https://onepetro.org/speuncv/proceedings-abstract/12uncv/all-12uncv/spe-154720-ms/158075 https://onepetro.org/speuncv/proceedings-abstract/12uncv/all-12uncv/spe-154720-ms/158075 https://onepetro.org/speuncv/proceedings-abstract/12uncv/all-12uncv/spe-154720-ms/158075 https://onepetro.org/speuncv/proceedings-abstract/12uncv/all-12uncv/spe-154720-ms/158075 https://onepetro.org/speior/proceedings-abstract/06ior/all-06ior/spe-99641-ms/141203 https://onepetro.org/speior/proceedings-abstract/06ior/all-06ior/spe-99641-ms/141203 https://onepetro.org/speior/proceedings-abstract/06ior/all-06ior/spe-99641-ms/141203 https://onepetro.org/speior/proceedings-abstract/06ior/all-06ior/spe-99641-ms/141203 https://onepetro.org/speior/proceedings-abstract/06ior/all-06ior/spe-99641-ms/141203 https://onepetro.org/po/article-abstract/15/04/270/74270 https://onepetro.org/po/article-abstract/15/04/270/74270 https://onepetro.org/po/article-abstract/15/04/270/74270 https://onepetro.org/po/article-abstract/15/04/270/74270 https://onepetro.org/speior/proceedings-abstract/74ior/all-74ior/spe-4747-ms/139447 https://onepetro.org/speior/proceedings-abstract/74ior/all-74ior/spe-4747-ms/139447 https://onepetro.org/speior/proceedings-abstract/74ior/all-74ior/spe-4747-ms/139447 https://search.proquest.com/openview/3c210248dbd82871fba94294b573d2b8/1?pq-origsite=gscholar&cbl=18750 https://search.proquest.com/openview/3c210248dbd82871fba94294b573d2b8/1?pq-origsite=gscholar&cbl=18750 https://search.proquest.com/openview/3c210248dbd82871fba94294b573d2b8/1?pq-origsite=gscholar&cbl=18750 https://search.proquest.com/openview/3c210248dbd82871fba94294b573d2b8/1?pq-origsite=gscholar&cbl=18750 https://ogst.ifpenergiesnouvelles.fr/articles/ogst/abs/2018/01/ogst180100/ogst180100.html https://ogst.ifpenergiesnouvelles.fr/articles/ogst/abs/2018/01/ogst180100/ogst180100.html https://ogst.ifpenergiesnouvelles.fr/articles/ogst/abs/2018/01/ogst180100/ogst180100.html https://ogst.ifpenergiesnouvelles.fr/articles/ogst/abs/2018/01/ogst180100/ogst180100.html https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.7b02897 https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.7b02897 https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.7b02897 https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.7b02897 https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.7b02897 https://onepetro.org/ree/article/10/04/415/197313 https://onepetro.org/ree/article/10/04/415/197313 https://onepetro.org/ree/article/10/04/415/197313 https://onepetro.org/ree/article/10/04/415/197313 https://onepetro.org/ree/article/10/04/415/197313 https://onepetro.org/speior/proceedings-abstract/08ior/all-08ior/spe-113997-ms/144280 https://onepetro.org/speior/proceedings-abstract/08ior/all-08ior/spe-113997-ms/144280 https://onepetro.org/speior/proceedings-abstract/08ior/all-08ior/spe-113997-ms/144280 https://onepetro.org/speior/proceedings-abstract/08ior/all-08ior/spe-113997-ms/144280 https://onepetro.org/speior/proceedings-abstract/08ior/all-08ior/spe-113997-ms/144280 https://onepetro.org/spelacp/proceedings-abstract/94lacpec/all-94lacpec/spe-26991-ms/55858 https://onepetro.org/spelacp/proceedings-abstract/94lacpec/all-94lacpec/spe-26991-ms/55858 https://onepetro.org/spelacp/proceedings-abstract/94lacpec/all-94lacpec/spe-26991-ms/55858 https://onepetro.org/spelacp/proceedings-abstract/94lacpec/all-94lacpec/spe-26991-ms/55858 https://ogst.ifpenergiesnouvelles.fr/articles/ogst/abs/2010/06/ogst09046/ogst09046.html https://ogst.ifpenergiesnouvelles.fr/articles/ogst/abs/2010/06/ogst09046/ogst09046.html https://ogst.ifpenergiesnouvelles.fr/articles/ogst/abs/2010/06/ogst09046/ogst09046.html https://ogst.ifpenergiesnouvelles.fr/articles/ogst/abs/2010/06/ogst09046/ogst09046.html https://onepetro.org/speocc/proceedings-abstract/07ocs/all-07ocs/spe-106042-ms/143568 https://onepetro.org/speocc/proceedings-abstract/07ocs/all-07ocs/spe-106042-ms/143568 https://onepetro.org/speocc/proceedings-abstract/07ocs/all-07ocs/spe-106042-ms/143568 https://onepetro.org/speocc/proceedings-abstract/07ocs/all-07ocs/spe-106042-ms/143568 https://onepetro.org/speatce/proceedings/05atce/spe-96914-ms/89420 https://onepetro.org/speatce/proceedings/05atce/spe-96914-ms/89420 https://onepetro.org/speatce/proceedings/05atce/spe-96914-ms/89420 https://onepetro.org/speatce/proceedings/05atce/spe-96914-ms/89420 https://onepetro.org/speatce/proceedings/05atce/spe-96914-ms/89420 https://onepetro.org/speior/proceedings-abstract/08ior/all-08ior/spe-113193-ms/143956 https://onepetro.org/speior/proceedings-abstract/08ior/all-08ior/spe-113193-ms/143956 https://onepetro.org/speior/proceedings-abstract/08ior/all-08ior/spe-113193-ms/143956 https://onepetro.org/speior/proceedings-abstract/08ior/all-08ior/spe-113193-ms/143956 https://onepetro.org/speior/proceedings-abstract/08ior/all-08ior/spe-113193-ms/143956 https://onepetro.org/speior/proceedings-abstract/04ior/all-04ior/spe-89391-ms/71292 https://onepetro.org/speior/proceedings-abstract/04ior/all-04ior/spe-89391-ms/71292 https://onepetro.org/speior/proceedings-abstract/04ior/all-04ior/spe-89391-ms/71292 https://onepetro.org/speior/proceedings-abstract/04ior/all-04ior/spe-89391-ms/71292 https://onepetro.org/speior/proceedings-abstract/04ior/all-04ior/spe-89391-ms/71292 https://onepetro.org/speokog/proceedings-abstract/13pos/all-13pos/spe-164511-ms/177703 https://onepetro.org/speokog/proceedings-abstract/13pos/all-13pos/spe-164511-ms/177703 https://onepetro.org/speokog/proceedings-abstract/13pos/all-13pos/spe-164511-ms/177703 https://onepetro.org/speokog/proceedings-abstract/13pos/all-13pos/spe-164511-ms/177703 https://onepetro.org/speatce/proceedings-abstract/15atce/3-15atce/d031s031r009/180468 https://onepetro.org/speatce/proceedings-abstract/15atce/3-15atce/d031s031r009/180468 https://onepetro.org/speatce/proceedings-abstract/15atce/3-15atce/d031s031r009/180468 https://onepetro.org/speatce/proceedings-abstract/15atce/3-15atce/d031s031r009/180468 https://onepetro.org/speatce/proceedings-abstract/15atce/3-15atce/d031s031r009/180468 https://onepetro.org/speatce/proceedings-abstract/15atce/3-15atce/d031s031r009/180468 https://www.sciencedirect.com/science/article/pii/s0920410519306515 https://www.sciencedirect.com/science/article/pii/s0920410519306515 https://www.sciencedirect.com/science/article/pii/s0920410519306515 https://www.sciencedirect.com/science/article/pii/s0920410519306515 https://www.sciencedirect.com/science/article/pii/s0920410519306515 https://www.sciencedirect.com/science/article/pii/s0263876216301332 https://www.sciencedirect.com/science/article/pii/s0263876216301332 https://www.sciencedirect.com/science/article/pii/s0263876216301332 https://www.sciencedirect.com/science/article/pii/s0263876216301332 https://www.sciencedirect.com/science/article/pii/s0263876216301332 https://search.proquest.com/openview/96ba20cd932defcce83c1c10b8bc7ab7/1?pq-origsite=gscholar&cbl=18750&diss=y https://search.proquest.com/openview/96ba20cd932defcce83c1c10b8bc7ab7/1?pq-origsite=gscholar&cbl=18750&diss=y https://search.proquest.com/openview/96ba20cd932defcce83c1c10b8bc7ab7/1?pq-origsite=gscholar&cbl=18750&diss=y https://onepetro.org/speior/proceedings/00ior/spe-59362-ms/132948 https://onepetro.org/speior/proceedings/00ior/spe-59362-ms/132948 https://onepetro.org/speior/proceedings/00ior/spe-59362-ms/132948 https://onepetro.org/speior/proceedings/00ior/spe-59362-ms/132948 https://onepetro.org/ree/article/10/02/176/197306 https://onepetro.org/ree/article/10/02/176/197306 https://onepetro.org/ree/article/10/02/176/197306 https://onepetro.org/ree/article/10/02/176/197306 https://onepetro.org/ree/article/10/02/176/197306 https://onepetro.org/po/article/14/04/269/108963 https://onepetro.org/po/article/14/04/269/108963 https://onepetro.org/po/article/14/04/269/108963 https://onepetro.org/po/article/14/04/269/108963 https://onepetro.org/speapog/proceedings-abstract/15apog/all-15apog/spe-176429-ms/181262 https://onepetro.org/speapog/proceedings-abstract/15apog/all-15apog/spe-176429-ms/181262 https://onepetro.org/speapog/proceedings-abstract/15apog/all-15apog/spe-176429-ms/181262 https://onepetro.org/speapog/proceedings-abstract/15apog/all-15apog/spe-176429-ms/181262 a. k. al-delfi and f. h. m. al-mahdawi / iraqi journal of chemical and petroleum engineering 23,3 (2022) 75 83 82 [27] h. zhang and b. bai, “preformed-particle-gel transport through open fractures and its effect on water flow,” spe j., vol. 16, no. 2, pp. 388–400, 2011, doi: 10.2118/129908-pa. [28] l. q. zhou daiyu, zhao ji, wang jin, “application of deep profile control technology in lunnan oilfield, tarim basin,” xinjiang pet. geol., vol. 35, 2014. [29] f. a. muhammed, “study and pilot test on a novel eor method coupling ppg conformance control and surfactant flooding,” missouri university of science and technology, 2014. [30] a. imqam, b. bai, c. xiong, m. wei, m. delshad, and k. sepehrnoori, “characterizations of disproportionate permeability reduction of particle gels through fractures,” spe asia pacific oil gas conf. exhib., vol. 2, pp. 1228–1241, 2014, doi: 10.2118/171531-ms. [31] d. d. smith et al., “the successful evolution of anton irish conformance efforts,” spe annu. tech. conf. exhib., vol. 6, pp. 3719–3727, 2006, doi: 10.2523/103044-ms. [32] r. j. larkin and p. g. creel, “methodologies and solutions to remediate inner-well communication problems on the sacroc co2 eor project: a case study,” spe/doe improv. oil recover. symp., 2008, doi: 10.2118/113305-ms. https://onepetro.org/sj/article-abstract/16/02/388/204355 https://onepetro.org/sj/article-abstract/16/02/388/204355 https://onepetro.org/sj/article-abstract/16/02/388/204355 https://onepetro.org/sj/article-abstract/16/02/388/204355 http://www.zgxjpg.com/en/abstract/abstract839.shtml http://www.zgxjpg.com/en/abstract/abstract839.shtml http://www.zgxjpg.com/en/abstract/abstract839.shtml http://www.zgxjpg.com/en/abstract/abstract839.shtml https://search.proquest.com/openview/cd7fdad60ab18b4db614a94eb799866f/1?pq-origsite=gscholar&cbl=18750 https://search.proquest.com/openview/cd7fdad60ab18b4db614a94eb799866f/1?pq-origsite=gscholar&cbl=18750 https://search.proquest.com/openview/cd7fdad60ab18b4db614a94eb799866f/1?pq-origsite=gscholar&cbl=18750 https://search.proquest.com/openview/cd7fdad60ab18b4db614a94eb799866f/1?pq-origsite=gscholar&cbl=18750 https://search.proquest.com/openview/cd7fdad60ab18b4db614a94eb799866f/1?pq-origsite=gscholar&cbl=18750 https://onepetro.org/speapog/proceedings-abstract/14apog/all-14apog/spe-171531-ms/212314 https://onepetro.org/speapog/proceedings-abstract/14apog/all-14apog/spe-171531-ms/212314 https://onepetro.org/speapog/proceedings-abstract/14apog/all-14apog/spe-171531-ms/212314 https://onepetro.org/speapog/proceedings-abstract/14apog/all-14apog/spe-171531-ms/212314 https://onepetro.org/speapog/proceedings-abstract/14apog/all-14apog/spe-171531-ms/212314 https://onepetro.org/speapog/proceedings-abstract/14apog/all-14apog/spe-171531-ms/212314 https://onepetro.org/speatce/proceedings-abstract/06atce/all-06atce/spe-103044-ms/140154 https://onepetro.org/speatce/proceedings-abstract/06atce/all-06atce/spe-103044-ms/140154 https://onepetro.org/speatce/proceedings-abstract/06atce/all-06atce/spe-103044-ms/140154 https://onepetro.org/speatce/proceedings-abstract/06atce/all-06atce/spe-103044-ms/140154 https://onepetro.org/speior/proceedings-abstract/08ior/all-08ior/spe-113305-ms/144035 https://onepetro.org/speior/proceedings-abstract/08ior/all-08ior/spe-113305-ms/144035 https://onepetro.org/speior/proceedings-abstract/08ior/all-08ior/spe-113305-ms/144035 https://onepetro.org/speior/proceedings-abstract/08ior/all-08ior/spe-113305-ms/144035 https://onepetro.org/speior/proceedings-abstract/08ior/all-08ior/spe-113305-ms/144035 a. k. al-delfi and f. h. m. al-mahdawi / iraqi journal of chemical and petroleum engineering 23,3 (2022) 75 83 83 أنظمة جل البولي اكريالميد للتحكم بالمطابقة : مراجعة فالح حسن محمد المهداوي و علي كريم الدلفي جامعة بغداد, كلية الهندسة, قسم هندسة النفط الخالصة من بدء االنتاجفي وقت مبكر المصاحبة للنفط اإلنتاج المرتفع للمياه يعود سبب انخفاض استخراج النفط و القديمة. تم المكامن. تعتبر الكميات الهائلة من إنتاج المياه مشكلة منتشرة تحدث في المكمنإلى عدم تجانس مياه وزيادة غير المتجانسة لتنظيم إنتاج ال للمكامن كعامل اغالقاستخدام نظام البولي أكريالميد بشكل متكرر . يتم تصنيف أنظمة البولي أكريالميد إلى ثالث فئات وفًقا لتكوينها وظروف التطبيق: هالم انتاج النفطكفاءة (.ppgمونومر في الموقع ، وهالم بوليمر في الموقع ، وهالم جسيمات ُمشكل مسبًقا ) عدادها وآلياتها. يتم تصني ppgتقدم هذه الورقة مراجعة شاملة لحالة ، على ppgsف العديد من أنواع وا سبيل المثال ، المواد الهالمية مسبقة التشكيل بحجم مليمتر ، والميكروجيالت ، والبوليمرات المتقاطعة الحساسة باإلضافة إلى ذلك ، تمت دراسة أهم ®. bright waterلدرجة الحموضة ، وحبيبات البوليمر المتضخمة ، و كفاءة التوصيل ، ، و ppgحقن ، و االنتفاخاء تقييم أداء الجل ، مثل سعة العوامل التي يجب مراعاتها أثن تتمو كذلك . ppgالعوامل المؤثرة على تصميم برنامج الحقن و االستخدامات الحقلية للـ بعناية. كما تم ذكر .ppgبعض الدراسات التجريبية على االشارة الى الموقع ، هالم الجسيمات مسبقة التشكيل ، التحكم في المطابقةبولي أكريالميد ، هالم في الكلمات الدالة: 18 vol.12 no.2 (june 2011) (short communications) iraqi journal of chemical and petroleum engineering vol.12 no.2 (june 2011) 18 – 20 issn: 1997-4884 a particular solution of the two and three dimensional transient diffusion equations adel al-hemiri chemical engineering department – university of baghdad abstract a particular solution of the two and three dimensional unsteady state thermal or mass diffusion equation is obtained by introducing a combination of variables of the form, η = (x+y) / √ct , and η = (x+y+z) / √ct, for two and three dimensional equations respectively. and the corresponding solutions are, θ t, x, y = θ0 erfc x +y √8ct and θ t, x, y, z = θ0 erfc x +y +z √12ct keywords: two and three dimensional equations, particular solution. introduction the unsteady state two and three dimensional diffusion equations may be solved by the method of fourier transform (separation of variables) or by numerical methods to obtain a general solution. however both these methods leads to a double or triple series of the characteristic function and two or three separate expansion problemsdepending, of course, on whether the equation is two or three dimensionalwhich is a difficult task that requires rigorous calculations[1,2,3]. thus in this work we present a solution easily obtained using the method of combination of variables in the same manner it was used to solve the one dimensional equation: ∂θ/∂t = c (∂2θ/∂x 2 ), where, the parameter η= x/√ct, giving the solution, θ = θ0 erf (x/√4ct). mathematical treatment consider the two dimensional transient equation, ∂θ ∂t = c ∂2θ ∂x 2 + ∂2θ ∂y 2 (1) iraqi journal of chemical and petroleum engineering university of baghdad college of engineering will be solved for an initial value of the function θ equal to zero, i.e. θ (0,x,y) = 0 (2) introducing the combined variable, η = x+y √ct (3) differentiating η with respect to t, x and y to find the equivalent forms of ∂θ ∂t , ∂2θ ∂x 2 and ∂2θ ∂y 2 in terms of η, thus: d η dt = − 1 2 x +y √ct = −η/2t (4) ∴ ∂θ ∂t = dθ dη . dη dt = − η 2t dθ dη (5) and dη dx = 1 √ct ; dη dy = 1 √ct (6) therefore, ∂2θ ∂x2 = ∂ ∂x ∂θ ∂x = d dη . dη dx dθ dη . dη dx = 1 ct d 2θ dη 2 (7) similarly, ∂2θ ∂y 2 = 1 ct d 2θ dη 2 (8) substituting equations 5, 7 and 8 into equation 1 gives, d 2θ dη 2 + 𝜂 4 dθ dη = 0 (9) by putting p = dθ dη and hence dp dη = d 2θ dη 2 this yields, dp dη + η p = 0 (10) therefore, p = a exp ( −η 2 8 ) = d θ d η (11) where a is constant of integration. integrating equation (11) gives, θ = a erf η √8 + b (12) applying the initial conditions, [equation (2)] leads to, 0 = a erf (∞) + b but, erf (∞) = 1 therefore, a = -b. then the solution becomes, θ = b [1 − erf η √8 ] θ = b erfc η √8 (13) the constant b may be found for a specified boundary condition. but, for convenience it is assigned a value of constant distribution, θ0 . then the final solution after substituting for η is, θ t, x, y = θ0 erfc x +y √8ct (14) similar procedure is applied to the three dimensional equation, ∂θ ∂t = c ∂2θ ∂x2 + ∂2θ ∂y 2 + ∂2θ ∂z 2 (15) with, η = x +y +z √ct (16) to give the solution, θ t, x, y, z = θ0 erfc x+y +z √12ct (17) aparticular solution of the two and three dimensional transient diffusion equations 20 vol.12 no.2 (june 2011) conclusions the particular solution obtained, here, is useful for in problems of transient heat and mass transfer in multi-dimensions. the solution may be used for problems of heat and mass diffusion in a flowing fluid through a conduit, described by the equation, νz ∂θ ∂t = c ∂2θ ∂x2 + ∂2θ ∂y 2 where νz is the average velocity along the length of the conduit. the solution is also useful for statistical equations and in problems of stochastic nature such as brownian motion. in applying the suggested solution the dimensions x, y and z should be normalized to vary between zero and unity and where the second derivative exist. nomenclature a, b: constant of integration. c: diffusion parameter. erf : error function. erfc: complimentary error function. p: dθ dη t: independent variable (time). νz: velocity in z-direction. x,y,z: independent variables (linear dimensions). η: combined variable, defined by eq. 3. θ: dependant variable. references 1wylie, c.r. and l.c. barrett, (1995), "advanced engineering mathematics", 6 th edition, mcgraw-hill. 2jenson, v.g. and g.v. jeffreys, (2001), "mathematical methods in chemical engineering", 4 th edition, academic press. 3bird, r.b.; w.e. stewart and e.n. lightfoot, (2002), "transport phenomena", 2 nd edition, john wiley. 4kreyszig, e., (1998), "advanced engineering mathematics", 8 th edition, john wiley. 5dennis, g.z. and m.r. cullen, (1999), "advanced engineering mathematics", 3 rd edition, jones and bartlett available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.23 no.4 (december 2022) 91 – 99 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: saif k. al-hlaichi, email: saif.abbas2008m@coeng.uobaghdad.edu.iq, name: faleh h. m. al-mahdawi, email: dr.f.h.m.almahdawi@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. optimization of drilling well design: a review saif k. al-hlaichi and faleh h. m. al-mahdawi petroleum engineering department, university of baghdad abstract drilling well design optimization reduces total authorization for expenditures (afe) by decreasing well constructing time and expense. well design is not a constant pattern during the life cycle of the field. it should be optimized by continuous improvements for all aspects of redesigning the well depending on the actual field conditions and problems. the core objective of this study is to deliver a general review of the well design optimization processes and the available studies and applications to employ the well design optimization to solve problems encountered with well design so that cost effectiveness and perfect drilling well performance are achievable. well design optimization processes include unconventional design(slimhole) compared with fat design, in addition to optimizing casing setting depth selection and casing string loads. finally, we demonstrate well trajectory design considerations and optimization. the optimization process that mentioned above is significantly reduce drilling cost and time since, slimhole design with smaller casing and hole size reduce mud volume cost, steel cost and pump fuel cost. optimum casing seat selection can ovoid serious problem such as kick and losses that increase nonproductive time (npt) if kick tolerance and downhole pressure profile is not considered. anticipating optimum stress loads in casing design is most effective way to reduce casing strings cost avoiding additional cost for designing with useless worst conditions. wellbore trajectory optimization with geomechnic consideration is major concern to reduce the problem encountered with high torque, drag, formation collapse that result stuck pipe and non-productive time (npt). keywords: optimization of well design, casing seat, casing design, wellbore trajectory. received on 17/06/2022, accepted on 22/07/2022, published on 30/12/2022 https://doi.org/10.31699/ijcpe.2022.4.11 1introduction as firms continue to expand their drilling operations in existing oil and gas areas across the globe, the time has come to optimize profits by improving drilling design to reduce associated costs [1]. the focal point of the optimization process is to reduce drilling time and associated cost per each well. horizontal drilling is a preferred technique for exploiting non-commercial reserves. unlike normal directional drilling, horizontal wells require extensive engineering work [2]. when drilling oil and gas wells, it is not possible to reach the well target in a single section due to formation pressure uncertainty. this presents difficulties and risks when drilling. consequently, the engineering team gets the opportunity to undertake a comprehensive field analysis. as a result of studying offset well data, geological and geomechanical investigations, a new well design is presented that is optimized for best drilling performance and decreased costs [3]. 2optimization of well design the focal point of the optimization process is to reduce drilling time and associated cost per each well [4]. engineers apply drilling optimization in order to drill wells more successfully and efficiently. directional drilling's specific objectives include good hole quality, robust directional control, high angle-build capacity, maximum durability, optimal penetration rate (rop), and minimal non-productive time. this may be achieved through optimum design. including hole and casing size optimization, casing seat selection, casing loads design, horizontal well trajectory and applications of new and high techniques [5]. alternative solutions to meet well plan goals and objectives are needed to optimize casing design. these options include the quantity of casing strings, casing seats, and cement top that can be used within the constraints of available resources [6]. casing setting depths are determined in accordance with the well's pore pressure and fracture pressure, which are frequently acquired through an offset well. other design considerations, such kick tolerance and differential sticking constraints, are also considered [7]. planned wellbore trajectory is required for directional and horizontal drilling. it's especially critical for multiwell platforms, where a number of considerations must be taken into account prior to determining the ultimate well path. to improve well trajectory, essential mathematical formulations must be created to reflect changes in directional well planning and profile [8]. drilling expenses will be minimized by collaborating with the team from the beginning of the well design stage to ensure that the well reaches its intended destination in a regulated and safe way [9]. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:saif.abbas2008m@coeng.uobaghdad.edu.iq mailto:dr.f.h.m.almahdawi@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2022.4.11 s. k. al-hlaichi and f. h. m. al-mahdawi / iraqi journal of chemical and petroleum engineering 23,4 (2022) 91 99 92 lummuas defined the philosophy of optimized drilling that is, use the first well's record as a basis for computations and apply optimal design and methods to the second and third wells, negotiating a $6.00/ft. field price much sooner. by using optimal design and methods, an operator can drill more wells each year or develop wells that might otherwise be uneconomical [10]. 2.1. typical (fat) and unconventional (slimhole) well design a well that was drilled using standard casing and bit sizes is known as a "fat design". in general, the most of wells drilled in the majority of fields across the world follow a three-section hole size structure. the surface hole is 17 1/2" in diameter (13 3/8" casing), the intermediate hole is 12 14" in diameter (9 5/8" casing), and the production hole is 8 12" in diameter (7" casing). as indicated in the fig. 1 [11]. “slimhole design” unconventional design reduces hole sections and casing strings to the smallest functional size. risk-based design may be employed to match the well's purpose. initial cost savings were anticipated by comparing hole size, steel/casing, disposal, and fluid needs [12]. slimhole industry was a 1950s cost-effective option. oil corporations didn't focus slimhole drilling throughout the 1960s and 1970s. in the 1980s, sweden developed a slimhole technique that reduced shallow reservoir drilling expenses by 75%. late 1980s thinking changed because flat oil prices and the necessity to expand exploration results in a cost-effective manner. since then, slimhole drilling has become an alternative to traditional oil and gas drilling. in the early 1990s, slimhole uses developed, allowing advancements in well completion to permit widespread slimhole use [13]. fig. 1. design decision tree [11] 2.2. casing seat selection the key design phase for constructing the well plan is identifying the depths to which the casing will be driven and sealed. the designer must evaluate geological variables such as formation and fracture gradients, as well as hole difficulties, internal business standards, and, in many situations, a variety of regulatory requirements [14]. 2.2.1. casing setting depth (csd) selection method the top-down technique begins with the selection of the conductor depth and then uses pore and fracture gradient data to compute the subsequent casing point, whereas the bottom-up technique relies on pore and fracture pressure data to establish the casing setting depth. for drilling wells, the casing point is established at total depth by determining a needed casing diameter at full depth for drilling wells. when it comes to drilling for exploration, the top-down approach is preferred over bottom-up, as seen in fig. 2. however, the top-down approach can be utilized in difficult subsurface geological circumstances; therefore, not all drilling wells use the bottom-up approach [15]. fig. 2. idealized casing seat selection [16] 2.2.2. landmark® casingseat software one of the main applications of this software is specifying the best shoe placements based on downhole s. k. al-hlaichi and f. h. m. al-mahdawi / iraqi journal of chemical and petroleum engineering 23,4 (2022) 91 99 93 pressure variation, and the engineer design parameters such kick tolerance and differential pipe sticking. in addition, other important applications can be provided by this software are the creation and maintenance of mud schedules and the determination of casing and hole diameters [17]. 2.3. casing loads design casing design consists of identifying characteristics that impact casing fail and selecting the safest and most costeffective casing types and weight for a particular application. there are three basic forces acting on the casing: rupture, stress, and collapse. these are the forces that exist inside the wellbore. they must be predetermined and kept below the criterion for casing strength [18]. 2.3.1. collapse load (pc) casing collapses if outer radial stress exceeds internal. empty casing maximizes collapse load. estimating casing collapse load can be calculated by using the formula below [18]. pc = pe – pi (1) 2.3.2. burst load (pb) the event that the internal radial load is higher than the exterior radial load, the casing will be subjected to a burst load, also known as a net burst load. utilizing the formula, determine the burst load, denoted by pb, at any location along the casing can be calculated by formula mentioned below [18]. pb = pi – pe (2) where: pi is internal pressure (psi), pe is exterior pressure (psi). it is important to take into consideration the pressure capacity of the wellhead and bop for burst design. the loads depicted in fig. 3 that are utilized to calculate the burst and collapse loads on the casing are determined from an operating scenario study [18]. fig. 3. radial load of casing [18] 2.3.3. axial load the loads on the casing may be tension or compression, as shown in fig. 4. casing axial stress varies with length. during installation, drilling, and production, the casing is stressed axially. the axial loads from each operation must be evaluated and added to yield the overall casing load [18]. 2.3.4. triaxial loading they are a total of three loads, and they are categorized as radial, axial, and tangential are depicted in fig. 5 [18]. fig. 4. axial load of casing [18] fig. 5. tri-axial loads on casing [18] 2.3.5. design factors in order to achieve the design loads, the actual loading data are multiplied by a design factor. design elements are mostly decided by experience and are impacted by casing failure implications [18]. s. k. al-hlaichi and f. h. m. al-mahdawi / iraqi journal of chemical and petroleum engineering 23,4 (2022) 91 99 94 2.3.6. landmark® stresschecktm software casing strings are created and analysed by this tool. stresscheck can construct casing strings at desired specifications. stresscheck reduces total casing costs by automating the specification of real burst, collapse, and axial loads, by optimizing the quantity and casing length sections, not cruellest load capacity profiles. compared to typical enclosure designs, 40% can be saved. fig. 6 demonstrates casing design procedures, elements, and conditions [19]. fig. 6. casing design process [18] 2.4. horizontal well profile design horizontal wells are drilled at an angle of up to ninety degrees via curved sections and then horizontally into the reservoir. horizontally into the rock, then. in practical situations, the inclination angle of horizontal wells ranges from 80 to 100 degrees. in a horizontal well with perfect slope, the angle is 90 degrees. there are three types of horizontal well patterns: short (30 to 200 feet radius of curvature), medium (200 to 1,000 feet), and long (1,000 to 3,000 feet) turn radius [8]. 2.4.1. well profile design considerations a. single curve design hole angle design rises from 0 to 90 degrees as shown in fig. 7. if this design is used, formation and drilling bha build-up tendencies must be known to avoid losing the target resulting from high or insufficient build rate. if the build rate is lower, the well route falls underneath the target. if it is too great, it goes over. both cases need excellent repair [20]. b. double curve design if build up is too rapid, the well path would be above the target, necessitating re-drilling. the well path will be below the reservoir if the build rate is reduced, prohibiting drilling. fig. 8 shows how a tangent portion below the initial build-up curve might solve the above problems. some reservoirs tilt internally [20]. fig. 7. single curve design [20] fig. 8. double curve design [20] s. k. al-hlaichi and f. h. m. al-mahdawi / iraqi journal of chemical and petroleum engineering 23,4 (2022) 91 99 95 2.4.2. the landmark® compasstm software the well trajectory is created utilizing, a tool compasstm software that enables speedy and exact design of wells and early identification of possible problems. on the list of capabilities are survey and planning techniques, torque-drag optimization, anticollision plotting with moving cylinder, and ellipse of uncertainty. it aims to enhance the effectiveness and costeffectiveness of directed well planning and wellbore monitoring [21]. 2.4.3. well bore trajectory optimization wellbore design involves optimizing trajectory. optimizing wellbore trajectory reduces geostress loads and extends wellbore service life. fixing a reservoir's surface increases the need for trajectory optimization. several methods are used to compare wellbore trajectory options. as a wellbore stability indicator, mechanical insitu stresses are significant. optimal well orientation for wellbore stability lowers normal stress difference. in-situ tensions dictate well direction. rock mechanics help determine wellbore trajectory. the amount and position of the max. horizontal loads can be determined from wellbore failures such as breakouts, washes, and drillinginduced fractures [8]. 3literature review many researchers studied different aspects of well design optimization related with fat and slimhole well design casing setting depth selection, casing loads design and wellbore trajectory optimization. 3.1. slimhole well design compared with conventional (fat) design studies using the slim hole optimization design is an application that got the attention of several researchers who studied and applied possible casing and hole size reduction in different aspects and applications of drilling wells. kroell and spoerker. in this study, the impacts of drilling on well productivity were reviewed, and contemporary completion techniques were emphasized. comparison of conventional drilling and slimhole formation-damaging potential. throughout the well's life cycle, the economic arguments for adopting slimhole technology during drilling are assessed against predicted low productivity. numerous studies and simulations of the influence of slimhole well configuration on inflow performance revealed that a wellbore diameter reduction has a little direct impact on inflow performance. by definition, high-productivity wells are unsuitable for slimhole completions. slimhole completion is possible for low to medium production reservoirs. economic benefits must be carefully weighed against any downsides, and a design strategy must be based on life-cycle well economics [22]. worrall et al. they showed that since 1987, 46 wells have utilized slim hole drilling. since daily progress no significantly reduces with reduced hole diameters, the design of the well may be streamlined. reduced expenses by one-fourth activity reduction reduces environmental effect. using complementary assessment and completing techniques, oil companies may reduce the size of their wells, hence decreasing field development expenses. they also illustrated the possibilities of slim hole drilling for the oil industry. wells account for an average of sixty percent of the entire cost of a project. this drilling technique seems to have the ability to drastically reduce these expenditures, and consequently the costs associated with field development [23]. david and vogelsberg. demonstrated that by decreasing the horizontal hole diameter from 8.75" to 6.7”, well construction expenses are reduced by 25%. they analysed the expense of decreasing the lateral hole size from 8.5"/5.5" to 6.75"/4.2". downhole equipment, drill strings, rig capabilities, and drilling fluid formulation have all been enhanced to increase rop. to maintain stimulation efficacy and well value, completions with smaller holes were constructed. in many geological plays, well building costs decreased by approximately 25 percent, making unconventional assets a more appealing investment [12]. 3.2. casing seat selection studies several researchers worked on casing setting depth optimization based on well conditions and kick tolerance. azi. designing casing setting depth for development well furak was obtained with 442 feet of seawater depth. the depth of each casing is determined via downhole pressure variation studies as well as bottom-up estimations of casing setting depth. the rotary table must produce zero. conductor casing is 1010 feet deep with an equal mud of 8.5 ppg, casing surface depth is 2495 feet with 9.4 ppg, intermediate casing is 6470 feet with 10 ppg, and production casing is 9810ft. with 11.3 ppg [7]. santos. a method for planning the set depths of surface and intermediate casing was presented using the concept of kick tolerance. the method was implemented in microcomputer software written in fortran. using the kick tolerance concept, the proposed method adopts an innovative way to discover the casing set depth that is the shallow [24]. assi. determined the casing seat depth. the setting elements that should be considered are fracture gradient, pore pressure, and remaining rock lithologies. the casing seat is better defined when the drilling fluid is specified. each well's casing is evaluated based on fracture and pore pressure and bottom-up technique. the case study shows that well a has a conductor casing that is 47 meters long, a casing surface that is 533 meters long, and an intermediate casing setting that is 1882 meters long. the depth of the production casing is 3441 m. both the bottom-up approach as well as the collapse pressure method produced comparable results [25]. s. k. al-hlaichi and f. h. m. al-mahdawi / iraqi journal of chemical and petroleum engineering 23,4 (2022) 91 99 96 othman. examined the relationship between casing depth and kick tolerance and well stability by doing sensitivity analyses on selected theoretical well data. the depth of the well casing shoe was calculated and deemed acceptable by the well integrity criteria [26]. holasek. determined using seismic, leak-proof capacity analysis, shallow pore and fracture pressure prediction deepens 20" casings. 20 " casing accurate analysis will enable the casing string to be placed deeper after the conductor is established in the flexible clay [15]. 3.3. casing design studies several researchers made casing to meet the goals of casing for different well conditions. they did this by taking into account the following optimization understandings through casing grading properties and cost. samuel and gonzale. the design of multistring casing was optimized for complicated loads, annulus gas growth, and well head expansion. casings for drilling stages are selected to save design expenses. casing strength, drift diameter, casing section length, quantity of sections, wellhead growth, and casing inventory are accounted for during optimization. the branch-and-bound heuristic provides casing design with structure information. this decreases the optimization effect of annular gas expansion and wellhead rise. it is cost-effective to optimize annuli fluid expansion-wellhead development. effectiveness will be determined by the annulus gas expansion-wellhead growing issue [6]. panagiotis. deviated, deep well casing (type slanted at target depth of 13000 ft), after constructing the pore and fracture pressure profile, the number of casing threads is decided. then, each section's outer diameters (od) and equivalent mud density (emd) must be supplied. a well survey must convert tvd to measured depth (md). the enclosure was designed for maximum force. burst, collapse, and stress must be calculated to determine casing thickness and grade [27]. maitham. studied drilling risk evaluation and management of deformation in a 9 5/8-inch casing at abu-ghirab and halfaya oilfields by designing a new casing using landmark software. the new casing design enhances the bulk and quality of the casing. in halfaya oilfield, the best 9 5/8-inch casing characteristics are (grade l80, weight 53.5 lb/ft and grade t95, weight 53.5 lb/ft) while in abu-ghirab oilfield, they are (grade l80, weight 47 lb/ft and grade t95, weight 58.4 lb/ft). change the kind of casing thread and increase the casing design's collapse and burst load safety factors in order to counteract the influence of external deformation caused by salt creeping and other extra pressure [28]. 3.4. wellbore trajectory optimization studies researchers have done a lot of work on well bore stability for wellbore trajectory optimization. manshid et al, mohiudin et al, and yi et al. provided horizontal and deviated wellbore stability models [29-31]. chabook et al. presented rock strength requirements affect wellbore stability and trajectory [32]. there are many other studies available on applying trajectory optimization to meet the optimum horizontal well design mentioned below. azar and samuel, mitchell, bourgoyn, and rabia. presented changes in the vertical and horizontal planes, directional well planning and well profile [33,34,35,20]. nie zhen. the wellbore trajectory and drilling schedule for the jeribeekirkuk reservoir in the halfaya oilfield were optimised. the trajectory optimization technique involves relocating the kick-off of the lower fars jeribee kirkuk directional well to upper fars. to lessen drill pipe sticking, the angle of inclination and deviated section length in lower fars are shortened. in addition, geomechanic properties of the anhydrite salty layer in lower fars were examined. using a mathematical model and criterion rules for wellbore deformation and stability in lower fars formation with various stratigraphy, the wellbore deformation during well drilling was simulated. so far, it has been used in 22 wells, proving that the intricacy of drilling a 311.2 mm hole has been handled [36]. al-jawad et al. they demonstrated horizontal well design features in ajeel field to increase productivity. elements of design include bit select and casing diameter, determination of setting depths and mud density, hydraulic systems, well geometry, and drill string simulation development. lastly, the recommended shortradius horizontal well with a build rate of 90 degrees per 100 feet can be done without exceeding the drill string's strength limits [37]. carden and grace. calculated torque and drag for various profiles. the influence of construction pace and ultimate inclination on predicted drag was evaluated in 16 situations. 1°, 2°, and 4° /100 ft were used in the computations. at each construction rate, four computations yielded 35°, 40°, 50°, and 60° inclinations. in each case, a 0.25 friction coefficient was assumed throughout the well. all variables were held constant except build rate, launch point, and ultimate incline. lowering the build rate to 1°/100 feet and building to 60° reduces trip out drag by 29.90%. to achieve the same goal, the hole must be 1,348 feet longer and drill pipe delivered logging may be needed. the 29.90% drag reduction may not be worth the additional drilling and logging expenditures. the start line would move from 3,970 to 7,111 feet. building to 60 at 1/100' instead of 40 at 2/100' would cut directional drilling expenditures. building at slower rates and steeper angles reduces drag. higher speeds and lower inclinations provide more drag. extended reach wells require greater torque and drag to reach ultimate depth and be cased [38]. 4future research in this study, we investigated that no one has tried to just look at how advanced drilling technologies effect on optimization of the drilling well design therefore, it is proposed to review down hole enlargement technology s. k. al-hlaichi and f. h. m. al-mahdawi / iraqi journal of chemical and petroleum engineering 23,4 (2022) 91 99 97 such as bi-centre bit and hydraulic reamer for optimizing drilling well design. moreover, managed pressure drill technique capability for eliminating casing string. not only that, special well design structure such as multilateral well with directional coiled tubing drilling (ctd) and lean well profile design with technological solution of straight hole drilling device (ssd) should be reviewed extensively. 5conclusion after reviewing a lot of studies and papers regarding the optimal method for designing a well, we can conclude that well design should be optimized in different stages of well planning to achieve drilling performance and reduce drilling cost without drop in well productivity. slim hole design is one of the optimization process which is cost effective and less risky than conventional (fat) design. slim hole drilling offers new oil industry options and field development costs can be lowered significantly. in addition, casing seat selection process should be optimized in such a way so that safe well control requirements and well integrity can be achieved. good practical directional profile and planning helps overcoming the associated challenges. casing design base that takes into consideration all of the expected loads confirm that mechanical integrity of the well is maintained. nomenclature csd casing setting depth ft. foot in. inch npt non-productive time pc collapse pressure pb burst pressure pe external pressure pi internal pressure ppg pound per gallon rop rate of penetration references [1] d. hankins, s. salehi, and f. karbalaei saleh, “an integrated approach for drilling optimization using advanced drilling optimizer,” j. pet. eng., vol. 2015, pp. 1–12, 2015, doi: 10.1155/2015/281276. [2] a. a. hashem and f. khalaf, “casing design considerations for horizontal wells,” j. king saud univ. eng. sci., vol. 6, no. 2, pp. 265–278, 1994, doi: 10.1016/s1018-3639(18)30611-1. [3] z. a. al kalbani, c. a. moreno, a. e. agguirre, m. aljahwari, a. sutherland, and m. elyas, “design optimization for drilling development wells,” soc. pet. eng. spe gas oil technol. showc. conf. 2019, gots 2019, no. november 1978, pp. 1–11, 2019, doi: 10.2118/198562-ms. [4] m. m. majeed and a. a. alhaleem, “enhancing drilling parameters in majnoon oilfield,” iraqi j. chem. pet. eng., vol. 20, no. 2, pp. 71–75, 2019, doi: 10.31699/ijcpe.2019.2.9. [5] e. wiktorski, a. kuznetcov, and d. sui, “rop optimization and modeling in directional drilling process,” soc. pet. eng. spe bergen one day semin. 2017, no. april, 2017, doi: 10.2118/185909ms. [6] g. r. samuel and a. gonzales, “optimization of multistring casing design with wellhead growth,” proc. spe annu. tech. conf. exhib., vol. delta, pp. 771–775, 1999, doi: 10.2118/56762-ms. [7] a. s. azi, “casing setting depth using bottom-up method for development well in the offshore,” j. eng. scince, vol. 1, no. 1, pp. 36–41, 2020. [8] m. halafawi and l. avram, “wellbore trajectory optimization for horizontal wells: the plan versus the reality,” j. oil, gas petrochemical sci., vol. 2, no. 1, pp. 49–54, 2019, doi: 10.30881/jogps.00024. [9] k. boonsri and j. natepracha, “potentiality for prewell planning in development field the next step to reducing time and enhancing well planning by collaboration drilling’s and geoscience’s workflow case study: development field in gulf of thailand,” soc. pet. eng. iadc/spe asia pacific drill. technol. conf. 2014 driv. sustain. growth through technol. innov., pp. 448–458, 2014, doi: 10.2118/170516-ms. [10] j. l. lummus, “drilling optimization,” j. pet. technol., vol. 22, no. 11, pp. 1379–1388, 1970, doi: 10.2118/2744-pa. [11] a. shokry and a. elgibaly, “well design optimization through the elimination of intermediate casing string,” j. king saud univ. eng. sci., no. xxxx, 2021, doi: 10.1016/j.jksues.2021.01.002. [12] e. david and p. vogelsberg, “reducing horizontal hole size from 8.5 to 6.75 reduces unconventional well construction cost by 25%,” soc. pet. eng. abu dhabi int. pet. exhib. conf. 2018, adipec 2018, 2019, doi: 10.2118/192953-ms. [13] k. k. millheim, m. prohaska, and b. thompson, “slim hole drilling technology past, present, future,” soc. pet. eng. petrovietnam 1995, ptv 1995, 1995, doi: 10.2118/30151-ms. [14] n. adams j, drilling engineering a complete well planning approach “, penwell publishing company, tulsa, oklahoma,1985. 1985. [15] f. r. holasek, r. k. singh, and s. shanker, “determination of 20-in. conductor setting depth in deepwater wells in the krishna-godavari basin offshore india,” spe/iadc indian drill. technol. conf. exhib. 2006 drill. india challenges oppor., vol. 2006, pp. 265–272, 2006, doi: 10.2523/103667ms. [16] “well engineering and production operations management system casing design manual,” no. november, 2001. https://downloads.hindawi.com/archive/2015/281276.pdf https://downloads.hindawi.com/archive/2015/281276.pdf https://downloads.hindawi.com/archive/2015/281276.pdf https://downloads.hindawi.com/archive/2015/281276.pdf https://downloads.hindawi.com/archive/2015/281276.pdf https://www.sciencedirect.com/science/article/pii/s1018363918306111 https://www.sciencedirect.com/science/article/pii/s1018363918306111 https://www.sciencedirect.com/science/article/pii/s1018363918306111 https://www.sciencedirect.com/science/article/pii/s1018363918306111 https://onepetro.org/spegots/proceedings-abstract/19gots/1-19gots/d012s024r001/219901 https://onepetro.org/spegots/proceedings-abstract/19gots/1-19gots/d012s024r001/219901 https://onepetro.org/spegots/proceedings-abstract/19gots/1-19gots/d012s024r001/219901 https://onepetro.org/spegots/proceedings-abstract/19gots/1-19gots/d012s024r001/219901 https://onepetro.org/spegots/proceedings-abstract/19gots/1-19gots/d012s024r001/219901 https://onepetro.org/spegots/proceedings-abstract/19gots/1-19gots/d012s024r001/219901 https://www.iasj.net/iasj/download/5e9b7b9b4d5b2c04 https://www.iasj.net/iasj/download/5e9b7b9b4d5b2c04 https://www.iasj.net/iasj/download/5e9b7b9b4d5b2c04 https://www.iasj.net/iasj/download/5e9b7b9b4d5b2c04 https://onepetro.org/speberg/proceedings-abstract/17berg/1-17berg/d011s003r002/193729 https://onepetro.org/speberg/proceedings-abstract/17berg/1-17berg/d011s003r002/193729 https://onepetro.org/speberg/proceedings-abstract/17berg/1-17berg/d011s003r002/193729 https://onepetro.org/speberg/proceedings-abstract/17berg/1-17berg/d011s003r002/193729 https://onepetro.org/speberg/proceedings-abstract/17berg/1-17berg/d011s003r002/193729 https://onepetro.org/speatce/proceedings-abstract/99atce/all-99atce/spe-56762-ms/60543 https://onepetro.org/speatce/proceedings-abstract/99atce/all-99atce/spe-56762-ms/60543 https://onepetro.org/speatce/proceedings-abstract/99atce/all-99atce/spe-56762-ms/60543 https://onepetro.org/speatce/proceedings-abstract/99atce/all-99atce/spe-56762-ms/60543 https://tljes.org/index.php/tljes/article/view/3 https://tljes.org/index.php/tljes/article/view/3 https://tljes.org/index.php/tljes/article/view/3 https://www.researchgate.net/profile/mohamed-halafawi/publication/331603155_wellbore_trajectory_optimization_for_horizontal_wells_the_plan_versus_the_reality_journal_of_oil_gas_and_petrochemical_sciences/links/5cf9d58a299bf13a38432cc2/wellbore-trajectory-optimization-for-horizontal-wells-the-plan-versus-the-reality-journal-of-oil-gas-and-petrochemical-sciences.pdf https://www.researchgate.net/profile/mohamed-halafawi/publication/331603155_wellbore_trajectory_optimization_for_horizontal_wells_the_plan_versus_the_reality_journal_of_oil_gas_and_petrochemical_sciences/links/5cf9d58a299bf13a38432cc2/wellbore-trajectory-optimization-for-horizontal-wells-the-plan-versus-the-reality-journal-of-oil-gas-and-petrochemical-sciences.pdf https://www.researchgate.net/profile/mohamed-halafawi/publication/331603155_wellbore_trajectory_optimization_for_horizontal_wells_the_plan_versus_the_reality_journal_of_oil_gas_and_petrochemical_sciences/links/5cf9d58a299bf13a38432cc2/wellbore-trajectory-optimization-for-horizontal-wells-the-plan-versus-the-reality-journal-of-oil-gas-and-petrochemical-sciences.pdf https://www.researchgate.net/profile/mohamed-halafawi/publication/331603155_wellbore_trajectory_optimization_for_horizontal_wells_the_plan_versus_the_reality_journal_of_oil_gas_and_petrochemical_sciences/links/5cf9d58a299bf13a38432cc2/wellbore-trajectory-optimization-for-horizontal-wells-the-plan-versus-the-reality-journal-of-oil-gas-and-petrochemical-sciences.pdf https://onepetro.org/speapdt/proceedings-abstract/14apdt/all-14apdt/spe-170516-ms/210530 https://onepetro.org/speapdt/proceedings-abstract/14apdt/all-14apdt/spe-170516-ms/210530 https://onepetro.org/speapdt/proceedings-abstract/14apdt/all-14apdt/spe-170516-ms/210530 https://onepetro.org/speapdt/proceedings-abstract/14apdt/all-14apdt/spe-170516-ms/210530 https://onepetro.org/speapdt/proceedings-abstract/14apdt/all-14apdt/spe-170516-ms/210530 https://onepetro.org/speapdt/proceedings-abstract/14apdt/all-14apdt/spe-170516-ms/210530 https://onepetro.org/speapdt/proceedings-abstract/14apdt/all-14apdt/spe-170516-ms/210530 https://onepetro.org/speapdt/proceedings-abstract/14apdt/all-14apdt/spe-170516-ms/210530 https://onepetro.org/speapdt/proceedings-abstract/14apdt/all-14apdt/spe-170516-ms/210530 https://onepetro.org/jpt/article/22/11/1379/163428/drilling-optimization https://onepetro.org/jpt/article/22/11/1379/163428/drilling-optimization https://onepetro.org/jpt/article/22/11/1379/163428/drilling-optimization https://www.sciencedirect.com/science/article/pii/s1018363921000027 https://www.sciencedirect.com/science/article/pii/s1018363921000027 https://www.sciencedirect.com/science/article/pii/s1018363921000027 https://www.sciencedirect.com/science/article/pii/s1018363921000027 https://onepetro.org/speadip/proceedings-abstract/18adip/2-18adip/d021s038r002/213371 https://onepetro.org/speadip/proceedings-abstract/18adip/2-18adip/d021s038r002/213371 https://onepetro.org/speadip/proceedings-abstract/18adip/2-18adip/d021s038r002/213371 https://onepetro.org/speadip/proceedings-abstract/18adip/2-18adip/d021s038r002/213371 https://onepetro.org/speadip/proceedings-abstract/18adip/2-18adip/d021s038r002/213371 https://onepetro.org/speptv/proceedings-abstract/95ptv/all-95ptv/spe-30151-ms/57408 https://onepetro.org/speptv/proceedings-abstract/95ptv/all-95ptv/spe-30151-ms/57408 https://onepetro.org/speptv/proceedings-abstract/95ptv/all-95ptv/spe-30151-ms/57408 https://onepetro.org/speptv/proceedings-abstract/95ptv/all-95ptv/spe-30151-ms/57408 https://onepetro.org/speidtc/proceedings-abstract/06idtc/all-06idtc/spe-103667-ms/140317 https://onepetro.org/speidtc/proceedings-abstract/06idtc/all-06idtc/spe-103667-ms/140317 https://onepetro.org/speidtc/proceedings-abstract/06idtc/all-06idtc/spe-103667-ms/140317 https://onepetro.org/speidtc/proceedings-abstract/06idtc/all-06idtc/spe-103667-ms/140317 https://onepetro.org/speidtc/proceedings-abstract/06idtc/all-06idtc/spe-103667-ms/140317 https://onepetro.org/speidtc/proceedings-abstract/06idtc/all-06idtc/spe-103667-ms/140317 https://onepetro.org/speidtc/proceedings-abstract/06idtc/all-06idtc/spe-103667-ms/140317 s. k. al-hlaichi and f. h. m. al-mahdawi / iraqi journal of chemical and petroleum engineering 23,4 (2022) 91 99 98 [17] casingseat; release 5000.1.7 training manual. 2010 by landmark graphics corporation. [18] heriot watt university, ''drilling engineering manual, ''petroleum engineering department, uk,2015. [19] stresscheck; release 5000.1.7 training manual. 2011 by landmark graphics corporation. [20] h. rabia, “well engineering & construction hussain rabia,” p. 1 to 789, 2002. [21] t. manual, “compass software release 5000.1.12,” no. 157605, 2014. [22] e. kroell and h. f. spoerker, “slimhole completion & production what to do after we drilled the well?” proc. drill. conf., pp. 705–712, 1996, doi: 10.2118/35129-ms. [23] r.n., worrall et al.: "an evolutionary approach to slim-hole drilling evaluations and completion", spe 24965, europec 1992, cannes, france. [24] o. santos, i. adasani, j. azar, and f. escorihuela, “determination of casing setting depth using kick tolerance concept,” 2007, doi: 10.2523/30220-ms. [25] a. h. assi, “geological considerations related to casing setting depth selection and design of iraqi oil wells (case study),” vol. 23, no. 2, pp. 35–42, 2022. 10.31699/ijcpe. [26] a. y. othman, “investigation of casing shoe depth determination taking into consideration the kick tolerance and well integrity,” no. may, 2014. [27] a. panagiotis, “design of the full casing program in a deviated well,” 2018. [28] i. maitham, “drilling risk management and economic evaluation in missan oil fields,” 2021. [29] a. k. manshad, h. jalalifar, and m. aslannejad, “analysis of vertical, horizontal and deviated wellbores stability by analytical and numerical methods,” 2014, doi: 10.1007/s13202-014-0100-7. [30] m. a. mohiuddin, k. khan, a. abdulraheem, and m. r. awal, “analysis of wellbore instability in vertical, directional, and horizontal wells using field data,” vol. 55, pp. 83–92, 2007, doi: 10.1016/j.petrol.2006.04.021. [31] x. yi, h. e. goodman, r. s. williams, w. k. hilarides, and c. corp, “building a geomechanical model for kotabatak field with applications to sanding onset and wellbore stability predictions,” 2008. [32] m. chabook, a. al-ajmi, and v. isaev, “international journal of rock mechanics & mining sciences the role of rock strength criteria in wellbore stability and trajectory optimization,” int. j. rock mech. min. sci., vol. 80, pp. 373–378, 2015, doi: 10.1016/j.ijrmms.2015.10.003. [33] azar jj, samuel gr. drilling engineering. pennwell books; 2007. [34] wi. mitchell, “advanced oilwell drilling engineering handbook & computer programs,” p. 605, 1995. [35] bourgoyn at, millheim kk, chenevert me, young fs. applied drilling engineering. spe textbook series. 1991;2. [36] z. nie, z. zhang, h. luo, and k. zou, “key technologies for directional well drilling in highpressure anhydrite salt layers,” nat. gas ind. b, vol. 5, no. 6, pp. 598–605, 2018, doi: 10.1016/j.ngib.2018.11.008. [37] m. s. al-jawad, h. abdul, and h. abdul, “design of horizontal well program for ajeel field,” vol. 15, no. 1, pp. 59–63, 2014. [38] r. s. carden and r. d. grace, “h orizontal and d irectional presented by,” 2007. https://d1wqtxts1xzle7.cloudfront.net/54674981/hussain_rabia_well_engineering___construction-libre.pdf?1507627983=&response-content-disposition=inline%3b+filename%3dhussain_rabia_index.pdf&expires=1671301399&signature=ygrtbokxglge0acrgwqaehlgtw~nz1xosycq3y0zpg6ynb2jyjxzq3jrufhpswnu-frmhsdg2dvmoqi-kdw24jal-k6krv4tlappekgr3q3irrbjft0-j8zmchk-klm9aa61dpjhqybqkby4gi-eq~fa4t6nv9hs~ywuslbtzsibne470leosn1h0j9etopuq-rldt0gtmlnqhnnbm7dvv~jum7-k1v2wlodvwmiz8bzepdsyjin~hvlovzgwp-plyryl0y0iuosopjdiat5wne6ndurxg4bbmd5txsxbbe5xi8xdku5j02qwsqf32rh8br4~cuv8ucyv2-tlr45ja__&key-pair-id=apkajlohf5ggslrbv4za https://d1wqtxts1xzle7.cloudfront.net/54674981/hussain_rabia_well_engineering___construction-libre.pdf?1507627983=&response-content-disposition=inline%3b+filename%3dhussain_rabia_index.pdf&expires=1671301399&signature=ygrtbokxglge0acrgwqaehlgtw~nz1xosycq3y0zpg6ynb2jyjxzq3jrufhpswnu-frmhsdg2dvmoqi-kdw24jal-k6krv4tlappekgr3q3irrbjft0-j8zmchk-klm9aa61dpjhqybqkby4gi-eq~fa4t6nv9hs~ywuslbtzsibne470leosn1h0j9etopuq-rldt0gtmlnqhnnbm7dvv~jum7-k1v2wlodvwmiz8bzepdsyjin~hvlovzgwp-plyryl0y0iuosopjdiat5wne6ndurxg4bbmd5txsxbbe5xi8xdku5j02qwsqf32rh8br4~cuv8ucyv2-tlr45ja__&key-pair-id=apkajlohf5ggslrbv4za https://onepetro.org/spedc/proceedings-abstract/96dc/all-96dc/spe-35129-ms/59381 https://onepetro.org/spedc/proceedings-abstract/96dc/all-96dc/spe-35129-ms/59381 https://onepetro.org/spedc/proceedings-abstract/96dc/all-96dc/spe-35129-ms/59381 https://onepetro.org/spedc/proceedings-abstract/96dc/all-96dc/spe-35129-ms/59381 https://onepetro.org/speeuro/proceedings-abstract/92eur/all-92eur/spe-24965-ms/54133 https://onepetro.org/speeuro/proceedings-abstract/92eur/all-92eur/spe-24965-ms/54133 https://onepetro.org/speeuro/proceedings-abstract/92eur/all-92eur/spe-24965-ms/54133 https://www.iasj.net/iasj/download/5e0790c612cfc5b8 https://www.iasj.net/iasj/download/5e0790c612cfc5b8 https://www.iasj.net/iasj/download/5e0790c612cfc5b8 https://www.iasj.net/iasj/download/5e0790c612cfc5b8 https://scholar.google.com/scholar?hl=en&as_sdt=0%2c5&q=%5b26%5d%09a.+y.+othman%2c+%e2%80%9cinvestigation+of+casing+shoe+depth+determination+taking+into+consideration+the+kick+tolerance+and+well+integrity%2c%e2%80%9d+no.+may%2c+2014.&btng= https://scholar.google.com/scholar?hl=en&as_sdt=0%2c5&q=%5b26%5d%09a.+y.+othman%2c+%e2%80%9cinvestigation+of+casing+shoe+depth+determination+taking+into+consideration+the+kick+tolerance+and+well+integrity%2c%e2%80%9d+no.+may%2c+2014.&btng= https://scholar.google.com/scholar?hl=en&as_sdt=0%2c5&q=%5b26%5d%09a.+y.+othman%2c+%e2%80%9cinvestigation+of+casing+shoe+depth+determination+taking+into+consideration+the+kick+tolerance+and+well+integrity%2c%e2%80%9d+no.+may%2c+2014.&btng= https://link.springer.com/article/10.1007/s13202-014-0100-7 https://link.springer.com/article/10.1007/s13202-014-0100-7 https://link.springer.com/article/10.1007/s13202-014-0100-7 https://link.springer.com/article/10.1007/s13202-014-0100-7 https://www.sciencedirect.com/science/article/abs/pii/s0920410506001264 https://www.sciencedirect.com/science/article/abs/pii/s0920410506001264 https://www.sciencedirect.com/science/article/abs/pii/s0920410506001264 https://www.sciencedirect.com/science/article/abs/pii/s0920410506001264 https://www.sciencedirect.com/science/article/abs/pii/s0920410506001264 https://onepetro.org/speapdt/proceedings-abstract/08apdt/all-08apdt/spe-114697-ms/144495 https://onepetro.org/speapdt/proceedings-abstract/08apdt/all-08apdt/spe-114697-ms/144495 https://onepetro.org/speapdt/proceedings-abstract/08apdt/all-08apdt/spe-114697-ms/144495 https://onepetro.org/speapdt/proceedings-abstract/08apdt/all-08apdt/spe-114697-ms/144495 https://onepetro.org/speapdt/proceedings-abstract/08apdt/all-08apdt/spe-114697-ms/144495 https://www.sciencedirect.com/science/article/pii/s2352854018301219 https://www.sciencedirect.com/science/article/pii/s2352854018301219 https://www.sciencedirect.com/science/article/pii/s2352854018301219 https://www.sciencedirect.com/science/article/pii/s2352854018301219 https://www.sciencedirect.com/science/article/pii/s2352854018301219 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/269 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/269 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/269 s. k. al-hlaichi and f. h. m. al-mahdawi / iraqi journal of chemical and petroleum engineering 23,4 (2022) 91 99 99 تصميم بئر الحفر امثلية سيف خضير عباس و فالح حسن محمد المهداوي جامعة بغداد, كلية الهندسة, قسم هندسة النفط الخالصة . تصميم من خالل تقليل وقت إنشاء البئر ونفقاته يقلل من إجمالي النفقات الكليةتحسين تصميم حفر اآلبار ب إعادة يجب تحسينه من خالل التحسينات المستمرة لجميع جوانلذلك الحقل. وجودالبئر ليس نمًطا ثابًتا خالل و هلدراسة ا. الهدف األساسي من هذه المرافقة لها لية والمشكالتالفع الحقليةتصميم البئر اعتماًدا على الظروف لبئر تقديم مراجعة عامة لعمليات تحسين تصميم البئر والدراسات والتطبيقات المتاحة لتوظيف تحسين تصميم ا ةدائيتحسين االتكلفة و من خالل تقليل فعاليةاكثر لحل المشكالت التي تواجه تصميم البئر بحيث يمكن تحقيق بئر نحيف( مقارنًة . تشمل عمليات تحسين تصميم اآلبار تصميًما غير تقليدي )بصورة مثاليةبئر الحفر حسين عرض اعتبارات تأخيًرا، .البطانة وأحمال تثبيتعمق ، باإلضافة إلى تحسين اختيار بالتصميم التقليدي .اإلنتاجياألنابيب والوقت غير استعصاء من أجل تقليل مسار البئرتصميم .مسار الحفرة، تصميم البطانة، تحديد مواضع البطانة، الحفرامثلية تصميم بئر الكلمات الدالة: iraqi journal of chemical and petroleum engineering vol.13 no.1 (march 2012) 1931 issn: 1997-4884 enhancement of biogas production and organic reduction of sludge by different pre-treatment processes riyadh s. almukhtar * , asawer a. alwasiti ** , mohammed t. naser * * university of technology, chemical engineering departement,baghdad, ** university of technology, petroleum technology depatement, baghdad, abstract anaerobic digestion (ad) is the most common process for dealing with primary and secondary wastewater sludge. in the present work, four pre-treatment methods (ultrasonic, chemical, thermal, and thermo-chemical) are investigated in al-rustumya wastewater treatment plant in order to find their effect on biogas production and volatile solid removal efficiency during anaerobic digestion. two frequencies of ultrasonic wave were used 30 khz and 50 khz during the pretreatment. sodium hydroxide was added in different amounts to give three ph values of 9, 10 and 11 in chemical pre-treating processes. the sludge was heated at 60 o c and 80 o c through thermal pre-treatment experiment. also, the sludge was treated thermochemically at 80 o c and ph 11 prior to anaerobic digestion. maximum biogas production (6009 ml) was obtained at ultrasonic pre-treatment method with 30 khz. the volumetric ratio of produced biogas to the initial volume of sludge is about 4:1. keywords: anaerobic digestion, pre-treatment methods, biogas production, volatile solid removal. 1. introduction sludge originated from wastewater treatment processes tends to have concentrated heavy metals and refractory organic compounds as well as potentially pathogenic organisms (viruses, bacteria and etc.). the disposal of sewage sludge has become a critical problem because of the increased cost of sludge disposal. in order to solve this problem, the recycling of sewage sludge has become necessary. anaerobic is the most common process for dealing with wastewater sludge containing primary and secondary sludge. anaerobic digestion (ad) is preferred to be used to reduce the high organic loading of sludge because of the rapid growth of the biomass that would ensue if the sludge were treated aerobically [1]. fraser [2] suggested that ad consists of three stages hydrolysis, acidogenesis and methanogenesis. the biological hydrolysis step represents the rate limiting step of the ad process [3]. many pre-treatment methods were studied to accelerate the rate limiting step and increase the biogas production. for example, neis et al, [4] studied the enhancement of anaerobic sludge digestion by ultrasonic disintegration. they found that higher removal rates with shorter sludge residence times was established and the university of baghdad college of engineering iraqi journal of chemical and petroleum engineering enhancement of biogas production and organic reduction of sludge by different pre-treatment processes 20 ijcpe vol.13 no.1 (march 2012) -available online at: www.iasj.net decrease in sludge residence time from 16 to 4 days showed no loss in degradation efficiency. sae eun oh [5] investigated the effects of ultrasonic frequency and power on disruption of biosolids in waste activated sludge and examined its effects on methane production of waste activated sludge treated by ultrasonic. his most important conclusions were: first, biosolids disruption in waste activated sludge on ultrasonic treatment was the most effective process at ultrasonic frequency of 40 khz and power of 0.3watt/ml, second, the ultrasonic exposure of 10 minutes at the 40 khz and 0.3watt/ml was expected to make a contribution to a higher disruption efficiency of biosolids in waste activated sludge and third, ultrasonic treatment enhanced the subsequence anaerobic digestion of volatile solids and caused an increase of biogas generation. the literature review of ultrasonic pre-treatment is presented in table (1). solubilization of sludge with alkaline pre-treatment was studied by kim et al [7]. the ph values of sludge were set at 9, 10 and 11 by the addition of 10n sodium hydroxide (naoh). in the alkaline treatment, the suspended solid concentration continuously decreased with the increase of ph from 9-11. the suspended solid removal efficiency of 20.9% for ph 11 was obtained and was in consistent with the finding of chen and coworkers [8]. table 1, literature review of ultrasonic pre-treatment (carrere et al, [6]) reference condition results tiehm et al, 1997 31khz, 3.6 w,64s, 22d increase in vs removal from 45.8% to 50.3% tiehm et al, 2001 41khz, 150min,8d increase of vs removal from 21.5%to 33.7% chu et al, 2002 20khz, 0.33w ,20 min, 100d increase of production from 143 to 292 g ts bien et al,2004 20khz , 180w, 60s, 28d 138% increase of biogas production salsabil et al, 2009 20khz,50d,batch 108000kj 84% increase of biogas production erden and filibeli, 2009 20khz, 35d, 9690 44% increase of biogas production elvira et al, 2009 30kw ,20d 37% increase in biogas production zhang et al [9] show that during the two-phase sludge anaerobic digestion, the sludge was hydrolyzed and acidified in the first phase, and then methane was produced in the second stage. pre-treating sludge at ph 10 for 8 days was reported, by which both sludge hydrolysis and acidification were increased, and the methane production was significantly improved. the effect of different sludge pretreatment methods on methane yield was compared. the ph 10 pre-treated sludge showed the highest accumulative methane yield (398 ml /gram of volatile suspended solids), which was 4.4 and 3.5 fold of the blank (untreated) and ultrasonic pre-treated sludge, respectively. an overview of chemical pre-treatment studies are shown in table (2). thermal pre-treatment of sludge was introduced to increase the biogas production. in the study of wang et al [11] the effectiveness of lower temperature pre-treatment (60-100 ) on mesophilic 37 anaerobic digestion of activated sludge was investigated. they concluded that thermal pretreatment resulted in a significant riyadh s. almukhtar, asawer a. alwasiti and mohammed t. naser -available online at: www.iasj.net ijcpe vol.13 no.1 (march 2012) 21 increase (30-50 %) in the methane yield. the effect of pre-treatment at 70 on mesophilic and thermophilic anaerobic digestion of primary and secondary sludge was studied by hariklia et al [12]. the pre-treatment step showed very positive effect on methane potential and production rate upon subsequent thermophilic digestion of primary sludge. the literature review of thermal pre-treating process is represented in table (3). table 2, overview of chemical hydrolysis pretreatment studies (appels et al, [10]) kim et al [14] studied the thermochemical pre-treatments of sludge by using naoh as alkali at a temperature of 121 and pressure of 1.5 atm. the study showed that the impact of the rate limiting step reduced by pretreatment and digestion efficiency of the sludge was consequently improved. the main scope of this work is to improve the digestion of anaerobic process under different pre-treatment processes of sludge, ultrasonic, chemical, thermal and thermochemical. table 3, literature review of impacts of thermal treatments on waste activated sludge mesophilic anaerobic digestion (bougrier et al. [13]) references conditions results haug et al, 1978 175 c, 30 min cstr, hrt=15 d increase of production from 115186 ml/g (62%) stuckey and mccarty, 1978 175c, 30min batch, 25d increase of convertibility of cod to from 48 to 68% tanaka et al, 1997 180 c,60min batch,8 d increasing of methane production (90%) fjordside et al, 2001 160 c cstr, 15 d increase of biogas production (60%) gavala et al, 2003 70 c , 7 d batch increase of production from 8.3 to 10.45 mmol/g vs input barjenbruch and kopplow, 2003 121 c, 60 min cstr, 20d increase of biogas production from 350 to 420 ml/g vss (20%) 2materials and methods: 2-1 materials: the sludge sample used in our experimental work was taken from thickeners that are found in alrustumya waste water treatment plant (wwtp) located in the north of baghdad-iraq, which processes 300m 3 /day of waste water. this sample is basically a mixture of primary and secondary waste activated sludge (was). the thickened sample is pretreated by one of the suggested methods and each 1liter of pre-treated sludge is then mixed with 500 ml of inoculums at the ratio of 2:1(v/v) prior to final digestion as shown in reference reagent results knezevic et al 1995 naoh *no significant improvement in vss reduction and improved gas production with increased naoh dosage inagaki et al 1997 naoh *improvement of digestion by 60% tanaka and kamyaba, 2002 naoh *60% increase of overall ss reduction carballa et al 2006 cao *no significant improvement in anaerobic digestion enhancement of biogas production and organic reduction of sludge by different pre-treatment processes 22 ijcpe vol.13 no.1 (march 2012) -available online at: www.iasj.net fig.1.this mixing of thickened sludge with inoculums is very helpful to accelerate hydrolysis step and increase anaerobic bacteria (i.e to shorten digestion time) [10]. the inoculums used is a digested sludge for 14 days at 37 operating temperature and ph 7. the general characteristics of raw and inoculums of each pre-treatment are shown in table (4). fig. 1, final sludge preparing steps table 4, main sludge sample characteristics. parameter raw sludge inoculum minimum value maximum value mean value minimum value maximum value mean value ts (g/ml) 0.128 0.161 0.152 0.106 0.146 0.132 vs (g/ml) 0.049 0.062 0.056 0.039 0.052 0.0462 nvs (g/ml) 0.096 0.112 0.0956 0.066 0.107 0.0862 tss (g/ml) 0.102 0.139 0.1248 0.084 0.138 0.112 vss (g/ml) 0.04 0.055 0.0482 0.031 0.045 0.0372 nvss(g/ml) 0.058 0.095 0.0766 0.051 0.106 0.0748 scod(g/l) 2.0 3.45 2.52 3.4 5.6 4.05 ph 6.8 8.2 7.46 6.9 7.4 7.26 2-2 blank test (control): in order to study the enhancement of digestion, the blank test (control) was done. it is anaerobic sludge digestion of 1.5 liter sludge (1liter raw sludge + 0.5 liter of inoculums) at the condition of 37 , ph 7 and sludge retention time of 14 days. 2-3 pre-treatment of sludge: 2-3.1 ultrasonic two 1liter of sludge samples were filled in stainless steel bath. one of them was exposed to 30 khz and the other to 50 khz frequency for 120 minutes. this was then mixed with inoculums sample in the ratio of 2:1 (v/v) to a final volume of 1.5 liters. riyadh s. almukhtar, asawer a. alwasiti and mohammed t. naser -available online at: www.iasj.net ijcpe vol.13 no.1 (march 2012) 23 2-3.2 chemical for alkaline pre-treatment a 3liters sludge sample was filled into three beakers of 1 liter capacity each and ph values of samples were set at 9, 10 and 11, respectively, by the addition of 10n sodium hydroxide. the beakers were mechanically stirred at 250rpm for 2hr. after alkaline pre-treatment, the hydrochloric acid (hcl) solution of 10n was added to set the ph at the required value (ph 7). the pre-treated sludge was then mixed with inoculums sludge in the ratio of 2:1(v/v) to 1.5liter. 2-3.3 thermal the low temperature pre-treatment was carried out at 60◦c and 80◦c in order to enhance thermal solubilization of particulate material. 1liter of sludge was heated by magnetic stirrer-heater for 60 min and the beaker was covered with plastic film (to avoid water evaporation) and gently stirred (10 rpm) to ensure temperature homogeneity. after a 60 min heating period, this sludge was cooled down to ambient temperature (25 ) and mixed with inoculums sludge at the ratio of 2:1(v/v) to accelerate the digestion rate; then the final volume of 1.5 liter was digested. 2-3.4 thermo-chemical the sludge sample was chemically pretreated by the addition of naoh to set the ph to 11 and then thermally heated up to 80 . this sample was then cooled down to ambient temperature and buffered by the addition of hcl to normal ph 7. 1liter of this sample was then inoculated at the ratio 2:1 (v/v) to a final 1.5 liter sludge sample. 2-4 experimental procedure sludge mixture is digested through 14 days in 2 liter jacketed bioreactors. organic matter was continuously mixed at a rate of 10 rpm to get uniform temperature and ph distribution. produced gas mixture was then washed by concentrated basic solution of naoh (10n). the acid gases ( ) are trapped by naoh and the remaining gas (methane) flows up to gas collector. the produced pressure through digestion, displace the equivalent volume of water to calibrated cylinder. the collected water volume indicates the produced methane gas volume. fig.2 shows the schematic experimental apparatus. each experiment was repeated three times, and they gave results with error of about ±8%. three reactors were used to accomplish anaerobic digestion. each reactor was made of clear plastic with 11.5 cm in diameter and 20 cm height. the reactor top cover contained six holes for gas outlet, ph sensor, temperature sensor, mixer road, acid and/or base feeding and sludge inlet or outlet. the sample was drained from bottom sampling hole as shown in fig. 2. the plastic top cover can be easily opened and closed after each run to clean the reactor. the jacket is made of clear plastic with 13cm diameter. cooling / heating water circulated continuously by water bath. fig. 3 shows the schematic reactor apparatus. 2-5 analysis volatile solid (vs) amount is the amount of combustible material in a sample. it is determined by an analytical method called “loss on ignition” which is the amount of matter that is volatilized and burned from a sample exposed to air at 550 ºc for 2 hours. the organic (carbon containing matter) is lost and the remaining matter is the mineral or ash component of the original sample. vs amount is usually reported as percent of total solids (ts), where ts are the sum of the vs and ash components [15]. enhancement of biogas production and organic reduction of sludge by different pre-treatment processes 24 ijcpe vol.13 no.1 (march 2012) -available online at: www.iasj.net after drying, total solids were incinerated in the same furnace at 550 for 2 hours. the solid remaining represents ash content (non volatile solid (nvs)). the difference between total solids and ash content called volatile solid. each analysis was done three times a week according to standard methods of 2540g (apha, awwa, wef [16]). 1anaerobic jacketed reactor 5sampling hole 9temperature sensor 2acid gas scrubber 6inlet hole 10ph probe 3gas collector 7water outlet hole 11acid/base inlet hole 4calibrated cylinder 8water inlet hole 12plastic tube connection fig.2, the schematic experimental apparatus fig.3, the schematic reactor apparatus 3results and discussions: 3-1 blank test: fig.4 displays the accumulated biogas through blank digestion test. it showed that accumulated biogas was gradually increased with digestion time. according to this figure the biogas production was started from the 1 st day and increased continuously at slow rate to reach the value of 295ml at the final day. this increase is compatible with the volatile removal fraction. the collected biogas at the end of digestion was 3309 ml. also it led to low vs reduction through 14 days of digestion. fig.5 illustrate that the first value of vs starts at 0.053 gm/ml and then roughly riyadh s. almukhtar, asawer a. alwasiti and mohammed t. naser -available online at: www.iasj.net ijcpe vol.13 no.1 (march 2012) 25 drops to a final value of 0.045 gm/ml after a long time of digestion. since the vs was the basic food of anaerobic bacteria;, therefore its amount continuously decreased during digestion process. this decrease can also be explained if we remember that the anaerobic digestion was carried out through three general steps of hydrolysis, acidogenesis and methanogenesis. through the hydrolysis step the particulate insoluble organic matter was converted to soluble organics by enzymatic reactions. during acidogenesis step, the dissolved organic materials were converted to amino acids, hydrogen and carbon dioxide and finally the methanogenesis bacteria consume the organic acid to produce methane gas. the continuation of the previous three steps within 14 days of the digestion process leads to a conversion of a large amount of volatile organic compounds to methane gas. the total vs removal efficiency of sludge, when exposed to biological treating (i.e. ad) reached a value of 15.09% after conventional digestion at 37 and ph 7.this value is possibly improved and maximized by using one of the suggested pre-treatment methods. 0 2 4 6 8 10 12 14 16 time, (day) 0 500 1000 1500 2000 2500 3000 3500 4000 a c c u m il a te d b io g a s p ro d u c ti o n ( m l) fig.4, accumulated biogas during blank test 0 2 4 6 8 10 12 14 16 time (day) 0.040 0.042 0.044 0.046 0.048 0.050 0.052 0.054 0.056 0.058 0.060 v o la ti le s o li d , v s ( g m /m l) fig.5, volatile solid concentration variation through blank test 3-2 ultrasonic pretreatment: fig.6 represents the accumulated biogas after digestion of sonicated sludge, during 14 days. according to this figure the biogas production was increased continuously for both studied frequencies. for example, the digestion of 30 khz pre-treated sludge yielded 6009 ml of biogas at the end of fermentation period while the digestion of 50 khz pre-treated sludge yielded lower volume of biogas which was 4397 ml for the mass sludge sample. by giving attention to accumulated biogas from untreated sludge digestion 3309ml, it could be observed that the significant enhancement was reached after sludge pre-treating. hence, an increase of 81.6% of biogas production was achieved at lower ultrasonic frequency. similar results were obtained by the work of salsabil et al [17] and those obtained in the work of elvira [18], were much higher while higher quantity of biogas was produced by the work of bien [19]. this difference may be due to the variation in the operating condition. the primary aim of ultrasonication pre-treatment process is to increase the sludge biodegradability to enhance the biogas production at lower srt in anaerobic digester. this is done by the ability of ultrasonication to induce cavitations, which lysis the cell walls of microbes and releases the enhancement of biogas production and organic reduction of sludge by different pre-treatment processes 26 ijcpe vol.13 no.1 (march 2012) -available online at: www.iasj.net intracellular components into the aqueous phase. the intracellular biopolymers solubilisation and conversion to the lower molecular weight compounds of sludge through hydrolysis; is a rate limiting step. therefore, the sonication parameters affect cavitations and accelerate the rate limiting step which effects on the sludge digestion. the volatile solid variation along the digestion period is shown in fig.6. the performance of anaerobic reactors was mainly evaluated in terms of increase in vs reduction and biogas [20]. the higher vs solid removal efficiency resulted from the 30 khz of pre-treated sludge (57.7%) and next resulted from 50 khz of pre-treated sludge (33.4%) as shown in fig.6. in other words, the process of cracking (as is evident in above figure) at 30 khz is much better than 50 khz and this is due to the phenomenon of the formation of bubbles as they grow up with the decrease in frequency, and the larger the bubbles, the more powerful and disruptive to the bacteria, organic materials particularly high molecular weight polymers, carbohydrates and lipids. the obtained results from processing by the waves are in compatible with other researchers such as tiehm et al [21] who found that the degree of disintegration was decreased when the frequency increased from 41 to 3217 khz. farooq et al [22] also found that the use of low power ultrasound was more effective than higher sound frequency in stimulating ad. 0 2 4 6 8 10 12 14 16 time, (day) -1000 0 1000 2000 3000 4000 5000 6000 7000 a c c u m il a te d b io g a s p ro d u c ti o n ( m l) 30 khz 50 khz fig.5, accumulated biogas after ultrasonic pretreatment 0 2 4 6 8 10 12 14 16 time (day) 0.015 0.020 0.025 0.030 0.035 0.040 0.045 0.050 0.055 0.060 v o la ti le s o li d , v s ( g m /m l) 30 khz 50 khz fig.6, effect of ultrasonic wave on volatile solid content 3-3 chemical pretreatment: the biogas production for different pre-treating ph values is shown in fig. 7. it illustrates that the biogas accumulation was affected by ph value of alkaline pre-treatment during fermentation process in the range of ph 9-11. the biogas production was increased with the increase of ph value. according to katsiris et al [23], the naoh used over pre-treating process was converted to na + and oh and when the ph of sludge samples increased, the bacterial surfaces become increasingly negatively charged. this creates high electrostatic repulsion which causes desorption of some part of extracellular polymers. increasing soluble organic compounds concentration means acceleration of hydrolysis step. riyadh s. almukhtar, asawer a. alwasiti and mohammed t. naser -available online at: www.iasj.net ijcpe vol.13 no.1 (march 2012) 27 acceleration of hydrolysis step by alkaline pre-treatment has a benefit of maximizing biogas production as an example. moreover, the addition of chemical agent through alkaline pretreatment acts as another technique too. the addition of naoh to sludge sample saponificated the present lipids and led to increase its lysis. so, alkaline pre-treatment is active when the sludge has a high concentration of lipids. similar results were obtained by the work of zhang et al [9].they showed that alkaline pre-treating caused significant increase in biogas production. much higher biogas yields were observed at ph (11) compared to other conditions. by comparing the chemically pretreated sludge with each others, it was found that lower vs removal efficiency was achieved at ph 9 and ph 10 (23.7% and 26.2% respectively) as shown in fig .8. significant improvement was done by ph 11 pretreated digester, which reached 44.1% after 14 days srt. generally, chemical pre-treatment can enhance the subsequent anaerobic digestion by the effect of alkali on microorganism and on the complex organic compounds of high molecular weight. regarding low vs removal improvement from chemical pretreatment digester, it does not mean that the pre-treatment could not break down the compounds but it is due to the addition of naoh. additional na+ into the raw sludge resulted in increasing ts content while sludge solubilization was taking place. therefore, the final ts amount of digested sludge was found to be relatively high. this result differs from that obtained by kenzevice [24] and carballa [25] who found that there was no significant improvement in the value of vs removal efficiency with increasing naoh dosage.this study agrees well with the work of tannaka[26]. 0 2 4 6 8 10 12 14 16 time, (day) -1000 0 1000 2000 3000 4000 5000 6000 a c c u m il a te d b io g a s p ro d u c ti o n ( m l) ph=9 ph=10 ph=11 fig.7, accumulated biogas after chemical pre-treating 0 2 4 6 8 10 12 14 16 tim e , (da y ) 0.020 0.025 0.030 0.035 0.040 0.045 0.050 v o la ti le s o li d v s , (g /m l) ph=9 ph=10 ph=11 fig.8, effect of alkaline pre-treatment on volatile solid content 3-4 thermal pretreatment: accumulated biogas of both thermal pre-treating conditions is shown in fig. 9. according to this figure, there is no significant increase in total accumulated biogas at the end of digestion period. depending on fig. 9, the pre-treatment of sludge by 60 temperature has resulted in lower biogas accumulation 3643ml as compared to 3749ml at 80 pretreating temperature. however, thermal pre-treatment methods improved the organic solubilization (acceleration of hydrolysis step through digestion) in addition to enhancement of sludge dewaterablity. the increasing of biogas production after thermal pretreatment was about 10-13% than that of blank enhancement of biogas production and organic reduction of sludge by different pre-treatment processes 28 ijcpe vol.13 no.1 (march 2012) -available online at: www.iasj.net test. similar results were obtained by the work of gavala et al [27]. while higher increase of biogas production was produced by the work of wang et al [11] of about (30-50)% when sludge was pretreated thermally at about (60100) 0 c. fig. 10 illustrates the modification of vs concentration through 14 days of digestion after both 60 and 80 pretreated sludge. according to that figure, the vs concentration of 60 pre-treated sludge decreased from 0.04 gm/ml to 0.031 gm/ml after long period of fermentation process. while vs concentration in 80 pre-treated sludge passed a wide range of variation starting at the point of 0.044 gm/ml and reached the point of 0.03 gm/ml after the same fermentation period. this difference in vs variations indicates that 80 of pre-treated sludge were digested better than 60 pre-treated sludge. this is due to the higher consumption of vs by present anaerobic microorganism. 0 2 4 6 8 10 12 14 16 time, (day) 0 1000 2000 3000 4000 5000 a c c u m il a te d b io g a s p ro d u c ti o n ( m l) 60 o c 80 o c fig. 9, accumulated biogas after thermal pre-treating 0 2 4 6 8 10 12 14 16 time (day) 0.028 0.030 0.032 0.034 0.036 0.038 0.040 0.042 0.044 0.046 0.048 0.050 v o la ti le s o li d , v s ( g m /m l) 60 o c 80 o c fig. 10, effect of thermal pretreatment on volatile solid content 3-5 thermo-chemical pretreatment: thermo-chemical pre-treating process is one of suggested techniques led to higher biogas production at the end of experiment. fig.11 shows the accumulated biogas after sludge pretreating process which led to accumulation of 5098 ml after 14 days of digestion. about 55.1% of total biogas was accumulated during the second week, so higher srt was required to increase biogas production as much as possible. dogan and dilek sanin [28] showed that thermochemical pre-treating process affected the final biogas production during 47 days of solid retention time. the higher biogas was achieved by mw+ ph 12 and mw + ph 11 and for both cases they were 18.9% more than the blank test. on the other hand, fig. 12 shows vs concentration drops from 0.055 gm/ml to 0.026 gm/ml continuously through disintegration period. the interesting value of total volatile solid removal efficiency of 52.73% was achieved after two weeks of sludge disintegration and only during the second week of digestion. 34.8% of total vs content was removed because of high bacterial activity. this amount of removal was reflected on the final biogas production. this result is in consistent with the work of kim, et al [14]. riyadh s. almukhtar, asawer a. alwasiti and mohammed t. naser -available online at: www.iasj.net ijcpe vol.13 no.1 (march 2012) 29 0 2 4 6 8 10 12 14 16 time, (day) 0 1000 2000 3000 4000 5000 6000 a c c u m il a te d b io g a s p ro d u c ti o n ( m l) fig. 11, accumulated biogas after thermo-chemical pre-treatment 0 2 4 6 8 10 12 14 16 time (day) 0.010 0.015 0.020 0.025 0.030 0.035 0.040 0.045 0.050 0.055 0.060 v o la ti le s o li d , v s ( g m /m l) fig.12, effect of thermo-chemical pretreatment on volatile solid content 4-conclusion: the following are the main conclusions drawn from this study: 1all the method, which have been suggested in this paper of pre-treatment acted successfully on different levels to enhance the digestion efficiencies, compared to control (blank test). these methods reduce the digestion time so the volume of the digesters may be reduced and hence less capital cost is required. 2arrangements of improving efficiencies of digestion processes depending on percentage increasing of biogas production which has been achieved in this study are described as follows: ultrasonic 30 khz (81.6%) > thermochemical ph (11) + 80 (54.06%) > chemical ph (11) (45.91%) > ultrasonic 50 khz (32.9%) > chemical ph (10) (28.41%) > thermal 80 (13.3%) > thermal 60 (10.10%) > chemical ph (9) (6.38%) 3the increasing of organic waste removal efficiency after pre-treating (without pre-treatment) is arranged as follow: processes, compared to blank test ultrasonic 30 khz (42.9%) > thermochemical ph (11) + 80 (37.63%) > chemical ph (11) (29%) > ultrasonic 50 khz (18.24%) > thermal 80 (16.72%) > chemical ph (10) (11.09%) > chemical ph (9) (8.58%) > thermal 60 (7.4%) acknowledgment: my special thanks are to al-rustumiya wastewater treatment plant staff for their help, encouragement and friendship. nomenclature: scod: soluble chemical oxygen demand [ppm]; vs: volatile solid [gm/ml]; wwtp: wastewater treatment plant; hrt: hydraulic retention time [day]; srt: solid retention time [day]; rpm: revolution per minute; ts: total solid [gm/ml] vs: volatile solid [gm/ml] nvs: non volatile solid [gm/ml] tss: total suspended solid [gm/ml] vss:volatile suspended solid [gm/ml] nvss: non volatile suspended solid [gm/ml] references: 1. clisso, m., (2010),“the anaerobic digestion process” [cited in http://water.me.vccs.edu/courses/en v108/anaerobic.htm] 2. fraser, k.d, (2010),“increased anaerobic digestion efficiencies via the use of thermal hydrolysis”, msc thesis submitted to the faculty of the virginia polytechnic institute and state university, blacksburg. enhancement of biogas production and organic reduction of sludge by different pre-treatment processes 30 ijcpe vol.13 no.1 (march 2012) -available online at: www.iasj.net 3. nies, u., nickel, k., and tiehm, a., (2000),“enhancement of anaerobic sludge digestion by ultrasonic disintegration”, water science and technology vol 42 no(9) pp 73-80. 4. sae eun oh, (2006),”improvement of anaerobic digestion rate of biosolids in waste activated sludge by ultrasonic pretreatment”, environ.eng.res, vol 11, no (3). 5. carrere.h, dumas.c, battimelli.a, batstone.d.j, delgenes.d.j, steyer.j.p, ferrer.i,(2010), “ pretreatment methods to improve sludge anaerobic degradability: areview” journal of hazardous materials 183 pp1-15. 6. kim, t-h., kim, t-h., yu, s., nam, y.k, choi, d.k, lee, s.r and lee, m.j, (2007),“soluilization of waste activated sludge with alkaline pretreatment and gamma ray irradiation”, journl. ind. eng. chem., vol (13), no(7). 7. chen .y, jiang. s, yuan. h, zhou. q, and gu. g, water. res., 41, 683 (2007)[cited in kim et al, 2007]. 8. zhang, d., chen, y., zhao, y., and zhu, v., (2010), “new sludge pretreatment method to improve methane production in waste activated sludge digestion“. environ.sci technol, 44, 48024808. 9. appels, l., baeyens, j., degre`ve, j. and dewil, r., (2008),“principles and potential of the anaerobic digestion of waste-activated sludge”, progress in energy and combustion science vol (34). 10. wang q, noguchi c, hara y, sharon c, kakimoto k and kato y, (1997),“studies on anaerobic digestion mechanism: influence of pretreatment temperature on biodegradation of waste activated sludge”, environ technol , vol 18 (cited in hariklia et al, 2003 ). 11. hariklia n.g, umur yenal, ioannis v. skiadas, peter westermann and birgitte k. ahring , (2003),”mesophilic and thermophilic anaerobic digestion of primary and secondary sludge. effect of pre-treatment at elevated temperature”, water research vol (37). 12. bougrier, c., albasi, c., delgen`es, j.p. and carr`ere, h., (2006) “effect of ultrasonic, thermal and ozone pre-treatments on waste activated sludge solubilisation and anaerobic biodegradability”, chemical engineering and processing vol (45). 13. kim, k., park, ch., kim, t., lee, m., kim, s., kim, s., and lee, j., (2003),“effect of various pretreatments for enhanced anaerobic digestion with waste activated sledge”, journal of bioscience and bioengineering vol 95 , no 3. 14. http://www.calrecycle.ca.gov/organi cs/glossary/conversion.htm, 2011. 15. apha, awwa, wef, 2005, standard methods for examination of water and wastewater, 21ed. american public association (apah), american water work association (awwa), water environmental federation (wef), washington dc 16. salsabil, m.r., prorot, a., casellas, m. and dagot, c., (2009),“pretreatment of activated sludge: effect of sonication on aerobic and anaerobic digestibility”, chemical engineering journal 148. 17. elvira p., m fdz-polanco, f i plaza, g garralón, f fdz-polanco,” (2009), ultrasound pre-treatment for anaerobic digestion improvement” water science and technology, 60( 6), pages: 15251532 18. bien jb, malina g, bien jd, wolny l.(2004),” enhancing anaerobic fermentation of sewage sludge for http://www.ncbi.nlm.nih.gov/pubmed?term=%22bien%20jb%22%5bauthor%5d http://www.ncbi.nlm.nih.gov/pubmed?term=%22malina%20g%22%5bauthor%5d http://www.ncbi.nlm.nih.gov/pubmed?term=%22bien%20jd%22%5bauthor%5d http://www.ncbi.nlm.nih.gov/pubmed?term=%22wolny%20l%22%5bauthor%5d http://www.ncbi.nlm.nih.gov/pubmed?term=%22wolny%20l%22%5bauthor%5d riyadh s. almukhtar, asawer a. alwasiti and mohammed t. naser -available online at: www.iasj.net ijcpe vol.13 no.1 (march 2012) 31 increasing biogas generation” j environ sci health , 39(4):939-49. 19. apul, o.g. and dilek sanin, f., (2010),“ultrasonic pretreatment and subsequent anaerobic digestion under different operational conditions”, bioresource technology vol (101). 20. tiehml, a., nickel, k., zellhorn, m., and neis, u., (2001), “ultrasonic waste activated sludge disintegration for improving anaerobic stabilization”, wat. res. vol. 35, no (8). 21. farooq, r., rehman, f., baig, f., sadique, m., khan, s., farooq, u., abdur rehman, farooq, a., pervez, a., mukhtar-ul-hassan and shaukat, s.f., (2009),“the effect of ultrasonic irradiation on the anaerobic digestion of activated sludge”, world applied sciences journal vol (6) no (2). 22. katsiris, n. and kouzeli-katsiri, a., (1987),”bound water content of biological sludges in relation to filtration and dewatering”, water res. 21 (11) (cited in neyens and baeyens, 2003). 23. knezevic, z., mavinic, d.s., anderson, b.c., (1995) pilot scale evaluation of anaerobic codigestion of primary and pretreated waste activated sludge. water environ. res. 67,835-841. 24. carballa, m., omil, f., alder, a.c., and lema, j.m, (2006) “comparison between the conventional anaerobic digestion of sewage sludge and its combination with a chemical or thermal pre-treatment concerning the removal of pharmaceuticals and personal care products” water science & technology vol 53 no (8). 25. tanaka s, kamiyama k. 2002 “thermochemical pre-treatment in the anaerobicdigestion of waste activated sludge”. water sci technol;46:173–9. 26. gavala, h.n., yenal, u., skiadas,i.v., westermann, p., ahring, b.k., (2003) “mesophilic and thermophilic digestion of primary and secondary sludge. effect of pretreatment at elevated temperature. water research 37(19), 4561-4572. 27. dogan, i., and dilek sanin, f., (2009),“alkaline solubilization and microwave irradiation as combined sludge disintegration and minimization method”, water research vol (43). http://www.ncbi.nlm.nih.gov/pubmed/15137710 http://www.ncbi.nlm.nih.gov/pubmed/15137710 available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.23 no.2 (june 2022) 1 – 8 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: rowaida n. abbas , email: rowida.abbas1307d@coeng.uobaghdad.edu.iq, name: ammar s. abbas, email: ammarabbas@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. kinetics and energetic parameters study of phenol removal from aqueous solution by electro-fenton advanced oxidation using modified electrodes with pbo2 and graphene rowaida n. abbas and ammar s. abbas chemical engineering department, college of engineering, university of baghdad, baghdad, iraq abstract the electro-fenton oxidation process is one of the essential advanced electrochemical oxidation processes used to treat phenol and its derivatives in wastewater. the electro-fenton oxidation process was carried out at an ambient temperature at different current density (2, 4, 6, 8 ma/cm2) for up to 6 h. sodium sulfate at a concentration of 0.05m was used as a supporting electrolyte, and 0.4 mm of ferrous ion concentration (fe2+) was used as a catalyst. the electrolyte cell consists of graphite modified by an electrodepositing layer of pbo2 on its surface as anode and carbon fiber modified with graphene as a cathode. the results indicated that phenol concentration decreases with an increase in current density, and the minimum phenol concentration obtained aft er 6 h of electrolysis at 8 ma/cm2 is equal to 7.82 ppm starting from an initial concentration about 155 ppm. the results obtained from the kinetic study of phenol oxidation at different current density showed that the reaction followed pseudo first -order kinetics regarding current density. energetic parameters like specific power consumption and current efficiency were also estimated at different current density. the results showed that an increase in current density caused an increase in the specific power consumption of the process and decreased current efficiency. keywords: wastewater, phenolic pollutants, electro-fenton oxidation, graphene, carbon fiber received on 03/04/2022, accepted on 22/05/2022, published on 30/06/2022 https://doi.org/10.31699/ijcpe.2022.2.1 1introduction hydrocarbon pollutants are spilling and leaking during exploration, manufacture, refining, transportation, and storing of products in several industries, causing pollution by these hydrocarbons [1]. among these hydrocarbon pollutants, monoaromatic hydrocarbons are strong environmental pollutants, persistent, and priority organic contaminants due to their high stability in the environment [2]. wastewater containing aromatic hydrocarbon is recalcitrant, more harmful than aliphatic components, and toxic to biological treatment [3, 4]. the most dangerous aromatic components in refinery wastewater are phenol and phenolic derivatives [5]. phenols are aromatic compounds enclosing one or more hydroxyl groups attached to the aromatic ring, and they are barely degraded by nature and remain a danger to the environment. phenol has been placed on the list of essential pollutants according to environmental protection agency (epa) and european agency (eu) that causes extreme toxicity for human and aquatic life [6]. phenolic compounds can accumulate in human and animal tissue and inhibit the synthesis and copying of deoxyribonucleic acid (dna) in a cell, and it prevents the reparation of dna in diploid human fibroblast [7, 8]. in some cases, high concentration phenol becomes mortal and causes burns and hurtful influence on the lung and liver, and hurt the central nervous system [9]. the rules by epa to lower phenol content in wastewaters to less than 1 mg/l, and according to the world health organization (who) recommendation, the permissible concentration of phenolic contents in potable waters is 0.001 mg/l [10], while the eu assigned that a maximum permitted limit of less than 0.0005 mg/l for phenol in all of its forms [11]. great interest has been raised today to reduce these pollutants from industrial wastewater before discharge into aqueous environments to ensure harmless removal to the ecosystem and avoid legal problems [12]. generally, there are two primary stages of wastewater treatment; the first is the pre-treatment step that consists of mechanical and physicochemical treatments. this pretreated effluent goes into advanced treatment. primary treatment is important because it prevents the purification equipment from damaging and lowering its efficiency by particulate matter pollutants and can be achieved by mechanical, physical, and chemical methods [13]. the next treatment step is advanced wastewater treatment which aims to remove and mineralize organic pollutants or reduce the contaminants in wastewater to the allowable limit before discharging. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:rowida.abbas1307d@coeng.uobaghdad.edu.iq mailto:ammarabbas@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2022.2.1 r. n. abbas and a. s. abbas / iraqi journal of chemical and petroleum engineering 23,2 (2022) 1 8 2 these processes are bioremediation [14], adsorption [15], membrane separation [16], microwave catalytic wet air oxidation [17], photocatalytic degradation [18], chemical oxidation [19], electrochemical oxidation process [20]. three ways could treat wastewater containing organic contaminants: complete oxidation of these organic compounds to form carbon dioxide and water, converting its chemical structures to another structure that is degraded easily, and the final way is the partial oxidation of these organic pollutants to form less toxic substance and biodegradable substance [21]. electrochemical treatment is one of the cleaner methods and eco-friendly environmental protection strategies and promising technologies for treating organic pollutants, especially phenol from aqueous solutions [22]. electrochemical technologies have many advantages that make them preferred in treating petroleum refinery wastewater, such as compatibility with the environment, adaptability, energy efficiency, selectivity, safety, flexibility to automation, and cost-effectiveness [23, 24]. whenever the conventional oxidation processes become inadequate in treating wastewater, advanced oxidation processes (aops) are used. aops replace conventional oxidation because the oxidation rate is prolonged, and the pollutants resist chemical oxidation or oxidize partially, forming contaminants of high toxicity [25]. in these processes, oxidation is attainted by hydroxyl radicals (•oh) generated electrochemically, which have a robust ability to oxidize. •oh, is strongest than other chemical oxidants and the strongest inorganic oxidant after fluorine [26]. the reaction rate velocity of these processes is high, and •oh is oxidized organics faster than ozone. so, the advanced electrochemical oxidation process is commonly used in treating the poisoning of organic pollutants such as phenol in industrial wastewater like coking wastewater, papermaking wastewater, and refinery wastewater [23, 27]. the electro-fenton oxidation process is one of the most critical aops as it reduces the cost and the risk of transportation of hydrogen peroxide in the traditional fenton process. the electro-fenton oxidation process involves the combination of addition ferrous ion and electro-generated of h2o2 in-situ. also, the electro-fenton is environmentally friendly and does not produce secondary pollutants due to that the electricity used is clean and pollution-free [28, 29]. hydrogen peroxide is produced by a two-electron reduction of oxygen at the appropriate cathodic potential on particular electrodes (eq. 1) [30]. 2 2 2 2 2 o h e h o + − + + → (1) •oh and •ooh are generated in the solution with the addition of fe2+ as catalyst (eqs. (2) and (3)). then, •oh and •ooh can attack and initiate the oxidation of pollutants (rh), as shown in eq. (4) [30]. 2 3 • 2 2 2 fe h o h fe oh h o + + + + + → + + (2) 3 2 • 2 2 fe h o fe ooh h + + + + → + + (3) • • 2 oh rh r h o+ → + (4) fe2+ ions are regenerated electro-catalytically through the fenton process by one-electron reduction of fe3+ eq. (5). 3 2 fe e fe + − + + → (5) the electrodes used in the oxidation processes are one of the most critical factors that determine the efficiency and selectivity of the removal efficiency and affect mechanisms and products [31]. the electrode material's performance variance is different in its ability to generate hydroxyl radicals and is affected by the side reaction at the electrode surface and in the bulk solution [32]. carbonous electrodes are commonly utilized as anodes in wastewater treatment because they provide high surface area per unit volume. carbonous electrodes such as graphite have porous substrates and corrosion resistance and can be easily covered by electrodeposition of active materials on their surface, such as pbo2 [29, 33]. the cathode material is also an important factor in the electrochemical oxidation processes of organic pollutants, especially in the electro-fenton processes, because hydrogen peroxide is produced by cathodic reduction of dissolved oxygen or air. the essential cathodes that using to increase the rate of hydrogen peroxide production in these processes are graphite (g), carbon fiber (cf), carbon felt, carbon black [34-36], carbon nanotube [37], graphene (gn) [38]. the present work investigates electrochemical oxidation techniques for phenol in an aqueous solution by using an electrochemical cell consisting of graphite modified by electrodeposition of pbo2 on its surface as anode and cf modified by gn as a cathode. the electro-fenton oxidation technique was used in the treatment process at a different current density (cd). also, reaction kinetics and energetic parameters were calculated and discussed. 2experimental work all chemicals used in experiments were of the reagent grade, and there was no need for further purification, and distilled water was used to prepare all aqueous solutions. cf (purchased from oem with 0.2 mm thickness and 3k yarn size) modified by gn was used as a cathode, and pbo2 on g (imported from graphite india limited (gil)) was used as anode in the electro-fenton oxidation process. the electrolytic solution of phenol removal experiments consisted of 400 ml of 150 ppm phenol solution. the process was carried out in an open, undivided perspex cell of 400 ml volume. the two electrodes' dimensions are (3*10 cm), and the distance between them was 3 cm. r. n. abbas and a. s. abbas / iraqi journal of chemical and petroleum engineering 23,2 (2022) 1 8 3 the mixing of 200 rpm was achieved by using an electrical gearbox stirrer (heidolph). sodium sulfates was used as supporting electrolyte with a concentration of 0.05 m to improve the electrolyte conductivity. a catalytic amount of feso4.7h2o was added before electrolysis started with a concentration of 0.4 mm. the current remained constant during each experiment, and different cd was used (2, 5, 8 ma/cm2) and supplied by a direct current (dc) power supply (korad ka3005d). compressed air (resun aco-001 electromagnetic air pump) was bubbled in the treated solution with a flow rate of 1 l/min for 20 minutes and remained for the electrolysis time until the experiment was completed. a schematic drawing of the electro-fenton oxidation system is shown in fig. 1. fig. 1. the electro-fenton oxidation system the experiments were carried out at ambient temperature, and the ph of the solution was adjusted initially at 3 by using concentrated sulfuric acid to optimize the production of hydrogen peroxide in acidic media that is saturated with dissolved oxygen. samples were withdrawn before and after electrolysis for up to 6 hours, and the phenol concentration was measured using an ultraviolet-visible spectrophotometer (thermo genesys 10 uv electron corporation madison w153711). the cod of the final treating solution after 6 h of electrolysis is also determined. 3results and discussions 3.1. effect of the cd of phenol concentration the electro-fenton oxidation process was carried out at different cd (2, 4, 6, 8) ma/cm2, and ferrous ion concentration (fe2+ = 0.4 mm), supporting electrolyte consisted of sodium sulfate (na2so3 = 50 mm) and at ambient temperature. the results of phenol concentration were recorded for up to 6 hours, plotted in figures (2). the phenol concentrations were 20.49, 16.27, 12.05, and 7.83 ppm after 6 hours of electrolysis at 2, 4, 6, and 8 ma/cm2 of cd, respectively, as shown in fig. 2. it is clear that increases in cd lead to decreasing phenol concentration. the reason is that increasing cd from 2 to 8 ma/cm2 leads to improving the rate of organic pollutants degradation. increasing organic degradation with cd is due to an increase in the amount of hydrogen peroxide generated electrochemically through the electrolysis. when the amount of hydrogen peroxide increases, the hydroxyl radical (•oh) increases to enough amount to react with the organic pollutants that existed in the treated solution, leading to minimize the phenol concentration [39, 40]. our results agree with the results of other researchers [41, 42]. fig. 2. the effect of applied cd on phenol concentration, fe2+ = 0.4 mm, na2so3 = 50 mm, and initial ph = 3 3.2. kinetic study of phenol removal by the electrofenton process the deterioration kinetics of phenol in simulated wastewater was estimated at different cd (2, 4, 6, 8 ma/cm2), and 0.4 mm of fe2+. the electro-fenton oxidation reaction can be represented generally by eq. (6). 2 2 ph oh co h o+ → + (6) assuming that the •oh concentration was constant with the experimental time because it is generated simultaneously by eq. (2), the reaction rate kinetics model can be written as eq. (7). [ ] [ ]t obs n t d cph k cph dt − = (7) where cph is phenol concentration and kobs is the observe rate constant. the oxidation reaction on the pbo2 anode and modified cf cathode was determined as the pseudo first-order rate expression and was estimated by non-linear regression for the kinetics data. the regression results and the obtained correlation coefficients (r2) indicated that the phenol removal reaction followed first-order kinetics for different cd. the obtained reaction rate constants were tabulated in table 1. as cd increasing, the reaction rate constant (k) increases due to increasing of •oh generation, which controls the oxidation reaction speed, and the reaction happens in bulk away from the anode [43]. time, h 0 1 2 3 4 5 6 7 p h e n o l c o n c e n tr a ti o n , p p m 0 20 40 60 80 100 120 140 160 cd=2 ma/cm 2 cd=4 ma/cm 2 cd=6 ma/cm 2 cd=8 ma/cm 2 r. n. abbas and a. s. abbas / iraqi journal of chemical and petroleum engineering 23,2 (2022) 1 8 4 table 1. rate constants of phenol degradation by electrofenton oxidation process at ambient temperature 0.4 mm fe2+, and different cd cd, ma/cm2 k, 1/h r 2, 2 0.3390 0.9922 4 0.3690 0.9931 6 0.4092 0.9931 8 0.4674 0.9912 3.3. energetic parameters: current efficiency (ce) and specific power consumption (spc) energetic parameters such as ce and spc also calculated for electro-fenton oxidation process at different current density. spc as a function of the consumed electrical charge q (ah/l) calculated and the results shown in figure (3). ce at each cd calculated based on cod removal after 6 h of electrolysis and the results shown in (table 2). these energetic parameters are commonly used to compare and assess electrochemical treatment techniques [44]. the ce donates to the interpretation of the change in the oxidative capacity of the process of electrochemical treatment with the applied current used (i), cell potential (v), and the removed amount of the pollutant (δcod) during the electrolysis time (t), as shown in eq. (8) [45]. ( ) 8 v cod f ce it  = (8) where f is the faraday constant (96485.33 c/mol) the amount of energy consumption in the system driven by electric energy is estimated via spc for electrolysis of a specific volume of treated solution (vs) by eq. (9) [45]. . s vit spc v conc =  (9) at the lowest value of cd (2 ma/cm2), the ce (%) is the highest value, and it is equal to 17.59. increasing cd promotes the removal efficiency of the electro-fenton oxidation process and decreases ce (%). the least value of ce (%) is achieved at a higher value of cd and it is equal to 4.78 after 6 h of electrolysis. our results agree with the previous study [46]. spc in (kw h/kg) increased proportionally as q increased with time (figure 3). the highest value of spc was obtained when q is equal to 3.6 ah/l after 6 h of electrolysis. the reason is that the gradual formation of intermediate is more difficult to oxidize and needs more time [47]. high cd increases the cell voltage, which means high power will be consumed. our results confirm with other researchers [46, 48] as they found the spc for electro-fenton oxidation processes in the same range. table 2, ce for cod removal via electro-fenton oxidation over of pbo2 on g as anode and gn on cf as cathode at different current density after 6 h of electrolysis cd, ma/cm2 cod removal ce % 2 82.2725 17.59 4 84.6425 9.05 6 87.0125 6.20 8 89.3825 4.78 fig. 3. the effect of the consumed specific charges on the spc at 0.4mm fe2+, and different cd for phenol removal by the electro-fenton oxidation process 4conclusion electro-fenton oxidation technique utilized to treated phenol and phenolic derivatives in diluted aqueous solution with a concentration of 155 ppm. the experiments carried out in a cell consist of pbo2 on g as anode and gn on cf as cathode. different current densities were applied to the system in the range between 2 to 8 ma/cm2 and the results recorded up to 6 hours of electrolysis. the results showed that increasing in cd leads to decrease phenol concentration because high cd improves the generation of hydrogen peroxide, thereby increasing the •oh that attacks and degrades the organic species. kinetic study of the oxidation reaction showed that the reaction is pseudo first order kinetic at different cd. energetic parameter results present that increasing in cd leads to increase in spc and the highest spc obtained is about 134.2 (kw h/kg) at 8 ma/cm2 after 6 h of treatment. increasing in cd cause to decrease in ce, and the reason is the formation of persistent intermediates and the highest ce was obtained at the lowest cd. q, ah/l 0 1 2 3 4 s p c , k w h /k g 0 20 40 60 80 100 120 140 160 cd=2 ma/cm 2 cd=4 ma/cm 2 cd=6 ma/cm 2 cd=8 ma/cm 2 r. n. abbas and a. s. abbas / iraqi journal of chemical and petroleum engineering 23,2 (2022) 1 8 5 references [1] s. j. varjani, e. gnansounou, and a. pandey, “comprehensive review on toxicity of persistent organic pollutants from petroleum refinery waste and their degradation by microorganisms,” chemosphere, vol. 188, pp. 280–291, 2017, doi: 10.1016/j.chemosphere.2017.09.005. [2] s. j. varjani and v. n. upasani, “a new look on factors affecting microbial degradation of petroleum hydrocarbon pollutants,” int. biodeterior. biodegrad., vol. 120, pp. 71–83, 2017, doi: 10.1016/j.ibiod.2017.02.006. [3] x. y. li, y. h. cui, y. j. feng, z. m. xie, and j. d. gu, “reaction pathways and mechanisms of the electrochemical degradation of phenol on different electrodes,” water res., vol. 39, no. 10, pp. 1972– 1981, 2005, doi: 10.1016/j.watres.2005.02.021. [4] s. randazzo, o. scialdone, e. brillas, and i. sirés, “comparative electrochemical treatments of two chlorinated aliphatic hydrocarbons. time course of the main reaction by-products,” j. hazard. mater., vol. 192, no. 3, pp. 1555–1564, 2011, doi: 10.1016/j.jhazmat.2011.06.075. [5] a. s. abbas, m. h. hafiz, and r. h. salman, “indirect electrochemical oxidation of phenol using rotating cylinder reactor,” iraqi j. chem. pet. eng., vol. 17, no. 4, pp. 43–55, 2016. [6] a. medel, e. bustos, k. esquivel, l. a. godínez, and y. meas, “electrochemical incineration of phenolic compounds from the hydrocarbon industry using boron-doped diamond electrodes,” int. j. photoenergy, vol. 2012, 2012, doi: 10.1155/2012/681875. [7] n. v. pradeep et al., “treatment of sugar industry wastewater in anaerobic downflow stationary fixed film (dsff) reactor,” sugar tech, vol. 16, no. 1, pp. 9–14, 2014, doi: 10.1007/s12355-013-0227-8. [8] p. praveen and k. c. loh, “simultaneous extraction and biodegradation of phenol in a hollow fiber supported liquid membrane bioreactor,” j. memb. sci., vol. 430, pp. 242–251, 2013, doi: 10.1016/j.memsci.2012.12.021. [9] f. karim and a. n. m. fakhruddin, “recent advances in the development of biosensor for phenol: a review,” rev. environ. sci. biotechnol., vol. 11, no. 3, pp. 261–274, 2012, doi: 10.1007/s11157-012-9268-9. [10] h. b. senturk, d. ozdes, a. gundogdu, c. duran, and m. soylak, “removal of phenol from aqueous solutions by adsorption onto organomodified tirebolu bentonite: equilibrium, kinetic and thermodynamic study,” j. hazard. mater., vol. 172, no. 1, pp. 353–362, 2009, doi: 10.1016/j.jhazmat.2009.07.019. [11] h. jiang, y. fang, y. fu, and q. x. guo, “studies on the extraction of phenol in wastewater,” j. hazard. mater., vol. 101, no. 2, pp. 179–190, 2003, doi: 10.1016/s0304-3894(03)00176-6. [12] a. olusegun et al., “we are intechopen , the world ’ s leading publisher of open access books built by scientists , for scientists top 1 %,” intech, vol. i, no. tourism, p. 38, 2012, doi: 10.1016/j.colsurfa.2011.12.014. [13] f. renault, b. sancey, p. m. badot, and g. crini, “chitosan for coagulation/flocculation processes an eco-friendly approach,” eur. polym. j., vol. 45, no. 5, pp. 1337–1348, 2009, doi: 10.1016/j.eurpolymj.2008.12.027. [14] a. chavan and s. mukherji, “treatment of hydrocarbon-rich wastewater using oil degrading bacteria and phototrophic microorganisms in rotating biological contactor: effect of n:p ratio,” j. hazard. mater., vol. 154, no. 1–3, pp. 63–72, 2008, doi: 10.1016/j.jhazmat.2007.09.106. [15] m. h. el-naas, s. al-zuhair, and m. a. alhaija, “removal of phenol from petroleum refinery wastewater through adsorption on date-pit activated carbon,” chem. eng. j., vol. 162, no. 3, pp. 997–1005, 2010, doi: 10.1016/j.cej.2010.07.007. [16] w. raza, j. lee, n. raza, y. luo, k. h. kim, and j. yang, “removal of phenolic compounds from industrial waste water based on membrane-based technologies,” j. ind. eng. chem., vol. 71, pp. 1–18, 2019, doi: 10.1016/j.jiec.2018.11.024. [17] y. sun, y. zhang, and x. quan, “treatment of petroleum refinery wastewater by microwave-assisted catalytic wet air oxidation under low temperature and low pressure,” sep. purif. technol., vol. 62, no. 3, pp. 565–570, 2008, doi: 10.1016/j.seppur.2008.02.027. [18] y. hou, j. qu, x. zhao, p. lei, d. wan, and c. p. huang, “electro-photocatalytic degradation of acid orange ii using a novel tio2/acf photoanode,” sci. total environ., vol. 407, no. 7, pp. 2431–2439, 2009, doi: 10.1016/j.scitotenv.2008.12.055. [19] y. yavuz, a. s. koparal, and ü. b. ögütveren, “phenol removal through chemical oxidation using fenton reagent,” chem. eng. technol., vol. 30, no. 5, pp. 583–586, 2007, doi: 10.1002/ceat.200600377. [20] x. duan, f. ma, z. yuan, x. jin, and l. chang, “electrochemical degradation of phenol in aqueous solution using pbo2 anode,” j. taiwan inst. chem. eng., vol. 44, no. 1, pp. 95–102, 2013, doi: 10.1016/j.jtice.2012.08.009. [21] r. g. saratale, k. j. hwang, j. y. song, g. d. saratale, and d. s. kim, “electrochemical oxidation of phenol for wastewater treatment using ti/pbo2 electrode,” j. environ. eng. (united states), vol. 142, no. 2, pp. 1–9, 2016, doi: 10.1061/(asce)ee.19437870.0001007. [22] a. ali, m. hewehy, x. chen, g. huang, and j. wang, “electrochemical reduction / oxidation in the treatment of heavy metal wastewater" "electrochemical reduction/oxidation in the treatment of heavy metal wastewater." journal of metallurgical engineering (me) volume 2, no. 4 (2013). https://www.sciencedirect.com/science/article/abs/pii/s0045653517314182 https://www.sciencedirect.com/science/article/abs/pii/s0045653517314182 https://www.sciencedirect.com/science/article/abs/pii/s0045653517314182 https://www.sciencedirect.com/science/article/abs/pii/s0045653517314182 https://www.sciencedirect.com/science/article/abs/pii/s0045653517314182 https://www.sciencedirect.com/science/article/abs/pii/s0045653517314182 https://www.sciencedirect.com/science/article/abs/pii/s0964830516308113 https://www.sciencedirect.com/science/article/abs/pii/s0964830516308113 https://www.sciencedirect.com/science/article/abs/pii/s0964830516308113 https://www.sciencedirect.com/science/article/abs/pii/s0964830516308113 https://www.sciencedirect.com/science/article/abs/pii/s0964830516308113 https://www.sciencedirect.com/science/article/abs/pii/s0043135405001120 https://www.sciencedirect.com/science/article/abs/pii/s0043135405001120 https://www.sciencedirect.com/science/article/abs/pii/s0043135405001120 https://www.sciencedirect.com/science/article/abs/pii/s0043135405001120 https://www.sciencedirect.com/science/article/abs/pii/s0043135405001120 https://www.sciencedirect.com/science/article/abs/pii/s0304389411008508 https://www.sciencedirect.com/science/article/abs/pii/s0304389411008508 https://www.sciencedirect.com/science/article/abs/pii/s0304389411008508 https://www.sciencedirect.com/science/article/abs/pii/s0304389411008508 https://www.sciencedirect.com/science/article/abs/pii/s0304389411008508 https://www.sciencedirect.com/science/article/abs/pii/s0304389411008508 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/232 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/232 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/232 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/232 https://www.hindawi.com/journals/ijp/2012/681875/ https://www.hindawi.com/journals/ijp/2012/681875/ https://www.hindawi.com/journals/ijp/2012/681875/ https://www.hindawi.com/journals/ijp/2012/681875/ https://www.hindawi.com/journals/ijp/2012/681875/ https://www.hindawi.com/journals/ijp/2012/681875/ https://link.springer.com/article/10.1007/s12355-013-0227-8 https://link.springer.com/article/10.1007/s12355-013-0227-8 https://link.springer.com/article/10.1007/s12355-013-0227-8 https://link.springer.com/article/10.1007/s12355-013-0227-8 https://www.sciencedirect.com/science/article/abs/pii/s0376738812009325 https://www.sciencedirect.com/science/article/abs/pii/s0376738812009325 https://www.sciencedirect.com/science/article/abs/pii/s0376738812009325 https://www.sciencedirect.com/science/article/abs/pii/s0376738812009325 https://www.sciencedirect.com/science/article/abs/pii/s0376738812009325 https://link.springer.com/article/10.1007/s11157-012-9268-9 https://link.springer.com/article/10.1007/s11157-012-9268-9 https://link.springer.com/article/10.1007/s11157-012-9268-9 https://link.springer.com/article/10.1007/s11157-012-9268-9 https://www.sciencedirect.com/science/article/abs/pii/s0304389409011303 https://www.sciencedirect.com/science/article/abs/pii/s0304389409011303 https://www.sciencedirect.com/science/article/abs/pii/s0304389409011303 https://www.sciencedirect.com/science/article/abs/pii/s0304389409011303 https://www.sciencedirect.com/science/article/abs/pii/s0304389409011303 https://www.sciencedirect.com/science/article/abs/pii/s0304389409011303 https://www.sciencedirect.com/science/article/abs/pii/s0304389409011303 https://www.sciencedirect.com/science/article/abs/pii/s0304389403001766 https://www.sciencedirect.com/science/article/abs/pii/s0304389403001766 https://www.sciencedirect.com/science/article/abs/pii/s0304389403001766 https://www.sciencedirect.com/science/article/abs/pii/s0304389403001766 https://www.sciencedirect.com/science/article/abs/pii/s0014305708007222 https://www.sciencedirect.com/science/article/abs/pii/s0014305708007222 https://www.sciencedirect.com/science/article/abs/pii/s0014305708007222 https://www.sciencedirect.com/science/article/abs/pii/s0014305708007222 https://www.sciencedirect.com/science/article/abs/pii/s0014305708007222 https://www.sciencedirect.com/science/article/abs/pii/s0304389407013982 https://www.sciencedirect.com/science/article/abs/pii/s0304389407013982 https://www.sciencedirect.com/science/article/abs/pii/s0304389407013982 https://www.sciencedirect.com/science/article/abs/pii/s0304389407013982 https://www.sciencedirect.com/science/article/abs/pii/s0304389407013982 https://www.sciencedirect.com/science/article/abs/pii/s0304389407013982 https://www.sciencedirect.com/science/article/abs/pii/s1385894710006066 https://www.sciencedirect.com/science/article/abs/pii/s1385894710006066 https://www.sciencedirect.com/science/article/abs/pii/s1385894710006066 https://www.sciencedirect.com/science/article/abs/pii/s1385894710006066 https://www.sciencedirect.com/science/article/abs/pii/s1385894710006066 https://www.sciencedirect.com/science/article/abs/pii/s1226086x1831400x https://www.sciencedirect.com/science/article/abs/pii/s1226086x1831400x https://www.sciencedirect.com/science/article/abs/pii/s1226086x1831400x https://www.sciencedirect.com/science/article/abs/pii/s1226086x1831400x https://www.sciencedirect.com/science/article/abs/pii/s1226086x1831400x https://www.sciencedirect.com/science/article/abs/pii/s1383586608001019 https://www.sciencedirect.com/science/article/abs/pii/s1383586608001019 https://www.sciencedirect.com/science/article/abs/pii/s1383586608001019 https://www.sciencedirect.com/science/article/abs/pii/s1383586608001019 https://www.sciencedirect.com/science/article/abs/pii/s1383586608001019 https://www.sciencedirect.com/science/article/abs/pii/s0048969708012758 https://www.sciencedirect.com/science/article/abs/pii/s0048969708012758 https://www.sciencedirect.com/science/article/abs/pii/s0048969708012758 https://www.sciencedirect.com/science/article/abs/pii/s0048969708012758 https://www.sciencedirect.com/science/article/abs/pii/s0048969708012758 https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.200600377 https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.200600377 https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.200600377 https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.200600377 https://www.sciencedirect.com/science/article/abs/pii/s1876107012001447 https://www.sciencedirect.com/science/article/abs/pii/s1876107012001447 https://www.sciencedirect.com/science/article/abs/pii/s1876107012001447 https://www.sciencedirect.com/science/article/abs/pii/s1876107012001447 https://www.sciencedirect.com/science/article/abs/pii/s1876107012001447 https://ascelibrary.org/doi/abs/10.1061/(asce)ee.1943-7870.0001007 https://ascelibrary.org/doi/abs/10.1061/(asce)ee.1943-7870.0001007 https://ascelibrary.org/doi/abs/10.1061/(asce)ee.1943-7870.0001007 https://ascelibrary.org/doi/abs/10.1061/(asce)ee.1943-7870.0001007 https://ascelibrary.org/doi/abs/10.1061/(asce)ee.1943-7870.0001007 https://ascelibrary.org/doi/abs/10.1061/(asce)ee.1943-7870.0001007 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abbas and a. s. abbas / iraqi journal of chemical and petroleum engineering 23,2 (2022) 1 8 6 [23] z. tasic, v. k. gupta, and m. m. antonijevic, “the mechanism and kinetics of degradation of phenolics in wastewaters using electrochemical oxidation,” int. j. electrochem. sci., vol. 9, no. 7, pp. 3473–3490, 2014. [24] s. ben abdelmelek, j. greaves, k. p. ishida, w. j. cooper, and w. song, “removal of pharmaceutical and personal care products from reverse osmosis retentate using advanced oxidation processes,” environ. sci. technol., vol. 45, no. 8, pp. 3665–3671, 2011, doi: 10.1021/es104287n. [25] e. brillas, i. sire, and m. a. oturan, “electrofenton process and related electrochemical technologies based on fenton ’ s reaction chemistry,” pp. 6570–6631, 2009. [26] j. krýsa, d. mantzavinos, p. pichat, and i. poulios, “advanced oxidation processes for water/wastewater treatment,” environ. sci. pollut. res., vol. 25, no. 35, pp. 34799–34800, 2018, doi: 10.1007/s11356-018-3411-2. [27] p. jin, r. chang, d. liu, k. zhao, l. zhang, and y. ouyang, “phenol degradation in an electrochemical system with tio 2/activated carbon fiber as electrode,” j. environ. chem. eng., vol. 2, no. 2, pp. 1040–1047, 2014, doi: 10.1016/j.jece.2014.03.023. [28] s. parsons, “advanced oxidation processes for water and wastewater treatment,” iwa publ., 2004. [29] e. rosales, m. pazos, m. a. longo, and m. a. sanromán, “electro-fenton decoloration of dyes in a continuous reactor : a promising technology in colored wastewater treatment,” vol. 155, pp. 62–67, 2009, doi: 10.1016/j.cej.2009.06.028. [30] m. zhou, q. yu, l. lei, and g. barton, “electrofenton method for the removal of methyl red in an efficient electrochemical system,” sep. purif. technol., vol. 57, pp. 380–387, 2007, doi: 10.1016/j.seppur.2007.04.021. [31] r. a. torres, w. torres, p. peringer, and c. pulgarin, “electrochemical degradation of psubstituted phenols of industrial interest on pt electrodes. attempt of a structure-reactivity relationship assessment,” chemosphere, vol. 50, no. 1, pp. 97–104, 2003, doi: 10.1016/s00456535(02)00487-3. [32] a. urtiaga, i. ortiz, á. anglada, a. urtiaga, and i. ortiz, “contributions of electrochemical oxidation to waste-water treatment: fundamentals and review of applications,” j. chem. technol. biotechnol., vol. 84, no. 12, pp. 1747–1755, 2009, doi: 10.1002/jctb.2214. [33] r. m. farinos, r. l. zornitta, and l. a. m. m. ruotolo, “development of three-dimensional electrodes of pbo2 electrodeposited on reticulated vitreous carbon for organic eletrooxidation,” j. braz. chem. soc., vol. 28, no. 1, pp. 187–196, 2017, doi: 10.5935/0103-5053.20160162. [34] m. pimentel, n. oturan, m. dezotti, and m. a. oturan, “phenol degradation by advanced electrochemical oxidation process electro-fenton using a carbon felt cathode,” appl. catal. b environ. 83, vol. 83, pp. 140–149, 2008. [35] a. özcan, y. şahin, a. s. koparal, and m. a. oturan, “degradation of picloram by the electrofenton process,” j. hazard. mater., vol. 153, no. 1–2, pp. 718–727, 2008, doi: 10.1016/j.jhazmat.2007.09.015. [36] j. liu, x. sun, p. song, y. zhang, w. xing, and w. xu, “high-performance oxygen reduction electrocatalysts based on cheap carbon black, nitrogen, and trace iron,” adv. mater., vol. 25, no. 47, pp. 6879–6883, 2013, doi: 10.1002/adma.201302786. [37] a. thiam, m. zhou, e. brillas, and i. sirés, “two-step mineralization of tartrazine solutions: study of parameters and by-products during the coupling of electrocoagulation with electrochemical advanced oxidation processes,” appl. catal. b environ., vol. 150–151, pp. 116–125, 2014, doi: 10.1016/j.apcatb.2013.12.011. [38] t. liu, k. wang, s. song, a. brouzgou, p. tsiakaras, and y. wang, “new electro-fenton gas diffusion cathode based on nitrogen-doped graphene@carbon nanotube composite materials,” electrochim. acta, vol. 194, pp. 228–238, 2016, doi: 10.1016/j.electacta.2015.12.185. [39] n. beqqal, m. s. yahya, m. el karbane, a. guessous, and k. el kacemi, “kinetic study of the degradation/mineralization of aqueous solutions contaminated with rosuvastatin drug by electrofenton: influence of experimental parameters,” j. mater. environ. sci., vol. 8, no. 12, pp. 4399–4407, 2017, doi: 10.26872/jmes.2017.8.12.464. [40] gökkuş, n. yıldız, a. s. koparal, and y. yıldız, “evaluation of the effect of oxygen on electro-fenton treatment performance for real textile wastewater using the taguchi approach,” int. j. environ. sci. technol., vol. 15, no. 2, pp. 449–460, 2018, doi: 10.1007/s13762-017-1404-1. [41] z. i. abbas and a. s. abbas, “optimization of the electro-fenton process for cod reduction from refinery wastewater,” environ. eng. manag. j., vol. 19, no. 11, pp. 2029–2037, 2021, doi: 10.30638/eemj.2020.192. [42] y. yavuz, a. s. koparal, and ü. b. öǧütveren, “treatment of petroleum refinery wastewater by electrochemical methods,” desalination, vol. 258, no. 1–3, pp. 201–205, 2010, doi: 10.1016/j.desal.2010.03.013. [43] s. li, d. bejan, m. s. mcdowell, and n. j. bunce, “mixed first and zero order kinetics in the electrooxidation of sulfamethoxazole at a boron-doped diamond (bdd) anode,” j. appl. electrochem., vol. 38, no. 2, pp. 151–159, 2008, doi: 10.1007/s10800007-9413-2. [44] j. r. bolton, k. g. bircher, w. tumas, and c. a. tolman, “figures-of-merit for the technical development and application of advanced oxidation technologies for both electricand solar-driven systems,” pure appl. chem., vol. 73, no. 4, pp. 627– 637, 2001, doi: 10.1351/pac200173040627. https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.654.9505&rep=rep1&type=pdf https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.654.9505&rep=rep1&type=pdf https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.654.9505&rep=rep1&type=pdf https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.654.9505&rep=rep1&type=pdf https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.654.9505&rep=rep1&type=pdf https://pubs.acs.org/doi/abs/10.1021/es104287n https://pubs.acs.org/doi/abs/10.1021/es104287n https://pubs.acs.org/doi/abs/10.1021/es104287n https://pubs.acs.org/doi/abs/10.1021/es104287n https://pubs.acs.org/doi/abs/10.1021/es104287n https://pubs.acs.org/doi/abs/10.1021/es104287n https://pubs.acs.org/doi/full/10.1021/cr900136g https://pubs.acs.org/doi/full/10.1021/cr900136g https://pubs.acs.org/doi/full/10.1021/cr900136g https://pubs.acs.org/doi/full/10.1021/cr900136g https://link.springer.com/article/10.1007/s11356-018-3411-2 https://link.springer.com/article/10.1007/s11356-018-3411-2 https://link.springer.com/article/10.1007/s11356-018-3411-2 https://link.springer.com/article/10.1007/s11356-018-3411-2 https://link.springer.com/article/10.1007/s11356-018-3411-2 https://www.sciencedirect.com/science/article/abs/pii/s2213343714000712 https://www.sciencedirect.com/science/article/abs/pii/s2213343714000712 https://www.sciencedirect.com/science/article/abs/pii/s2213343714000712 https://www.sciencedirect.com/science/article/abs/pii/s2213343714000712 https://www.sciencedirect.com/science/article/abs/pii/s2213343714000712 https://books.google.com.tr/books?hl=en&lr=&id=7nengjwaavgc&oi=fnd&pg=pr5&dq=%5b28%5d%09s.+parsons,+%e2%80%9cadvanced+oxidation+processes+for+water+and+wastewater+treatment,%e2%80%9d+iwa+publ.,+2004.&ots=zf37jhrsgz&sig=w9qggo3e-g07lafy5pvhnlgulbu&redir_esc=y#v=onepage&q=%5b28%5d%09s.%20parsons%2c%20%e2%80%9cadvanced%20oxidation%20processes%20for%20water%20and%20wastewater%20treatment%2c%e2%80%9d%20iwa%20publ.%2c%202004.&f=false https://books.google.com.tr/books?hl=en&lr=&id=7nengjwaavgc&oi=fnd&pg=pr5&dq=%5b28%5d%09s.+parsons,+%e2%80%9cadvanced+oxidation+processes+for+water+and+wastewater+treatment,%e2%80%9d+iwa+publ.,+2004.&ots=zf37jhrsgz&sig=w9qggo3e-g07lafy5pvhnlgulbu&redir_esc=y#v=onepage&q=%5b28%5d%09s.%20parsons%2c%20%e2%80%9cadvanced%20oxidation%20processes%20for%20water%20and%20wastewater%20treatment%2c%e2%80%9d%20iwa%20publ.%2c%202004.&f=false https://www.sciencedirect.com/science/article/abs/pii/s138589470900463x https://www.sciencedirect.com/science/article/abs/pii/s138589470900463x https://www.sciencedirect.com/science/article/abs/pii/s138589470900463x https://www.sciencedirect.com/science/article/abs/pii/s138589470900463x https://www.sciencedirect.com/science/article/abs/pii/s138589470900463x https://www.sciencedirect.com/science/article/abs/pii/s1383586607001967 https://www.sciencedirect.com/science/article/abs/pii/s1383586607001967 https://www.sciencedirect.com/science/article/abs/pii/s1383586607001967 https://www.sciencedirect.com/science/article/abs/pii/s1383586607001967 https://www.sciencedirect.com/science/article/abs/pii/s1383586607001967 https://www.sciencedirect.com/science/article/abs/pii/s0045653502004873 https://www.sciencedirect.com/science/article/abs/pii/s0045653502004873 https://www.sciencedirect.com/science/article/abs/pii/s0045653502004873 https://www.sciencedirect.com/science/article/abs/pii/s0045653502004873 https://www.sciencedirect.com/science/article/abs/pii/s0045653502004873 https://www.sciencedirect.com/science/article/abs/pii/s0045653502004873 https://www.sciencedirect.com/science/article/abs/pii/s0045653502004873 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.2214 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.2214 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.2214 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.2214 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.2214 https://www.scielo.br/j/jbchs/a/vggyqyjpzslnvkl6w7xqwsh/?lang=en&format=html https://www.scielo.br/j/jbchs/a/vggyqyjpzslnvkl6w7xqwsh/?lang=en&format=html https://www.scielo.br/j/jbchs/a/vggyqyjpzslnvkl6w7xqwsh/?lang=en&format=html https://www.scielo.br/j/jbchs/a/vggyqyjpzslnvkl6w7xqwsh/?lang=en&format=html https://www.scielo.br/j/jbchs/a/vggyqyjpzslnvkl6w7xqwsh/?lang=en&format=html https://www.scielo.br/j/jbchs/a/vggyqyjpzslnvkl6w7xqwsh/?lang=en&format=html https://www.sciencedirect.com/science/article/abs/pii/s0926337308000660 https://www.sciencedirect.com/science/article/abs/pii/s0926337308000660 https://www.sciencedirect.com/science/article/abs/pii/s0926337308000660 https://www.sciencedirect.com/science/article/abs/pii/s0926337308000660 https://www.sciencedirect.com/science/article/abs/pii/s0926337308000660 https://www.sciencedirect.com/science/article/abs/pii/s0304389407013027 https://www.sciencedirect.com/science/article/abs/pii/s0304389407013027 https://www.sciencedirect.com/science/article/abs/pii/s0304389407013027 https://www.sciencedirect.com/science/article/abs/pii/s0304389407013027 https://www.sciencedirect.com/science/article/abs/pii/s0304389407013027 https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.201302786 https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.201302786 https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.201302786 https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.201302786 https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.201302786 https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.201302786 https://www.sciencedirect.com/science/article/abs/pii/s092633731300756x https://www.sciencedirect.com/science/article/abs/pii/s092633731300756x https://www.sciencedirect.com/science/article/abs/pii/s092633731300756x https://www.sciencedirect.com/science/article/abs/pii/s092633731300756x https://www.sciencedirect.com/science/article/abs/pii/s092633731300756x https://www.sciencedirect.com/science/article/abs/pii/s092633731300756x https://www.sciencedirect.com/science/article/abs/pii/s092633731300756x https://www.sciencedirect.com/science/article/abs/pii/s0013468615311087 https://www.sciencedirect.com/science/article/abs/pii/s0013468615311087 https://www.sciencedirect.com/science/article/abs/pii/s0013468615311087 https://www.sciencedirect.com/science/article/abs/pii/s0013468615311087 https://www.sciencedirect.com/science/article/abs/pii/s0013468615311087 https://www.sciencedirect.com/science/article/abs/pii/s0013468615311087 http://www.jmaterenvironsci.com/document/vol8/vol8_n12/464-jmes-3183-beqqal.pdf http://www.jmaterenvironsci.com/document/vol8/vol8_n12/464-jmes-3183-beqqal.pdf http://www.jmaterenvironsci.com/document/vol8/vol8_n12/464-jmes-3183-beqqal.pdf http://www.jmaterenvironsci.com/document/vol8/vol8_n12/464-jmes-3183-beqqal.pdf http://www.jmaterenvironsci.com/document/vol8/vol8_n12/464-jmes-3183-beqqal.pdf http://www.jmaterenvironsci.com/document/vol8/vol8_n12/464-jmes-3183-beqqal.pdf http://www.jmaterenvironsci.com/document/vol8/vol8_n12/464-jmes-3183-beqqal.pdf https://link.springer.com/article/10.1007/s13762-017-1404-1 https://link.springer.com/article/10.1007/s13762-017-1404-1 https://link.springer.com/article/10.1007/s13762-017-1404-1 https://link.springer.com/article/10.1007/s13762-017-1404-1 https://link.springer.com/article/10.1007/s13762-017-1404-1 https://link.springer.com/article/10.1007/s13762-017-1404-1 https://www.researchgate.net/profile/ammar-abbas-10/publication/348365364_optimization_of_the_electro-fenton_process_for_cod_reduction_from_refinery_wastewater/links/5ffade0b299bf1408885fc38/optimization-of-the-electro-fenton-process-for-cod-reduction-from-refinery-wastewater.pdf https://www.researchgate.net/profile/ammar-abbas-10/publication/348365364_optimization_of_the_electro-fenton_process_for_cod_reduction_from_refinery_wastewater/links/5ffade0b299bf1408885fc38/optimization-of-the-electro-fenton-process-for-cod-reduction-from-refinery-wastewater.pdf https://www.researchgate.net/profile/ammar-abbas-10/publication/348365364_optimization_of_the_electro-fenton_process_for_cod_reduction_from_refinery_wastewater/links/5ffade0b299bf1408885fc38/optimization-of-the-electro-fenton-process-for-cod-reduction-from-refinery-wastewater.pdf https://www.researchgate.net/profile/ammar-abbas-10/publication/348365364_optimization_of_the_electro-fenton_process_for_cod_reduction_from_refinery_wastewater/links/5ffade0b299bf1408885fc38/optimization-of-the-electro-fenton-process-for-cod-reduction-from-refinery-wastewater.pdf https://www.researchgate.net/profile/ammar-abbas-10/publication/348365364_optimization_of_the_electro-fenton_process_for_cod_reduction_from_refinery_wastewater/links/5ffade0b299bf1408885fc38/optimization-of-the-electro-fenton-process-for-cod-reduction-from-refinery-wastewater.pdf https://www.sciencedirect.com/science/article/abs/pii/s0011916410001487 https://www.sciencedirect.com/science/article/abs/pii/s0011916410001487 https://www.sciencedirect.com/science/article/abs/pii/s0011916410001487 https://www.sciencedirect.com/science/article/abs/pii/s0011916410001487 https://www.sciencedirect.com/science/article/abs/pii/s0011916410001487 https://link.springer.com/article/10.1007/s10800-007-9413-2 https://link.springer.com/article/10.1007/s10800-007-9413-2 https://link.springer.com/article/10.1007/s10800-007-9413-2 https://link.springer.com/article/10.1007/s10800-007-9413-2 https://link.springer.com/article/10.1007/s10800-007-9413-2 https://link.springer.com/article/10.1007/s10800-007-9413-2 https://www.degruyter.com/document/doi/10.1351/pac200173040627/html https://www.degruyter.com/document/doi/10.1351/pac200173040627/html https://www.degruyter.com/document/doi/10.1351/pac200173040627/html https://www.degruyter.com/document/doi/10.1351/pac200173040627/html https://www.degruyter.com/document/doi/10.1351/pac200173040627/html https://www.degruyter.com/document/doi/10.1351/pac200173040627/html r. n. abbas and a. s. abbas / iraqi journal of chemical and petroleum engineering 23,2 (2022) 1 8 7 [45] z. i. abbas and a. s. abbas, “oxidative degradation of phenolic wastewater by electro-fenton process using mno2-graphite electrode,” j. environ. chem. eng., vol. 7, no. 3, p. 103108, 2019, doi: 10.1016/j.jece.2019.103108. [46] d. s. ibrahim, “electrochemical oxidation treatment of petroleum refinery effluent,” int. j. sci. &engineering res., vol. 4, no. 8, pp. 0–5, 2013, doi: 10.14299/00000. [47] b. boye, m. m. dieng, and e. brillas, “anodic oxidation, electro-fenton and photoelectro-fenton treatments of 2,4,5-trichlorophenoxyacetic acid,” j. electroanal. chem., vol. 557, pp. 135–146, 2003, doi: 10.1016/s0022-0728(03)00366-8. [48] c. a. martínez-huitle, s. ferro, and a. de battisti, “electrochemical incineration in the presence of halides,” electrochem. solid-state lett., vol. 8, no. 11, pp. 35–39, 2005, doi: 10.1149/1.2042628. https://www.sciencedirect.com/science/article/abs/pii/s2213343719302313 https://www.sciencedirect.com/science/article/abs/pii/s2213343719302313 https://www.sciencedirect.com/science/article/abs/pii/s2213343719302313 https://www.sciencedirect.com/science/article/abs/pii/s2213343719302313 https://www.sciencedirect.com/science/article/abs/pii/s2213343719302313 https://www.researchgate.net/profile/dhorgham-ibrahim/publication/267142453_electrochemical_oxidation_treatment_of_petroleum_refinery_effluent/links/561d621a08aecade1acb3bbd/electrochemical-oxidation-treatment-of-petroleum-refinery-effluent.pdf https://www.researchgate.net/profile/dhorgham-ibrahim/publication/267142453_electrochemical_oxidation_treatment_of_petroleum_refinery_effluent/links/561d621a08aecade1acb3bbd/electrochemical-oxidation-treatment-of-petroleum-refinery-effluent.pdf https://www.researchgate.net/profile/dhorgham-ibrahim/publication/267142453_electrochemical_oxidation_treatment_of_petroleum_refinery_effluent/links/561d621a08aecade1acb3bbd/electrochemical-oxidation-treatment-of-petroleum-refinery-effluent.pdf https://www.researchgate.net/profile/dhorgham-ibrahim/publication/267142453_electrochemical_oxidation_treatment_of_petroleum_refinery_effluent/links/561d621a08aecade1acb3bbd/electrochemical-oxidation-treatment-of-petroleum-refinery-effluent.pdf https://www.sciencedirect.com/science/article/abs/pii/s0022072803003668 https://www.sciencedirect.com/science/article/abs/pii/s0022072803003668 https://www.sciencedirect.com/science/article/abs/pii/s0022072803003668 https://www.sciencedirect.com/science/article/abs/pii/s0022072803003668 https://www.sciencedirect.com/science/article/abs/pii/s0022072803003668 https://iopscience.iop.org/article/10.1149/1.2042628/meta https://iopscience.iop.org/article/10.1149/1.2042628/meta https://iopscience.iop.org/article/10.1149/1.2042628/meta https://iopscience.iop.org/article/10.1149/1.2042628/meta r. n. abbas and a. s. abbas / iraqi journal of chemical and petroleum engineering 23,2 (2022) 1 8 8 دراسة الحركية والمعلمات النشطة إلزالة الفينول من محلول مائي مخفف بواسطة أكسدة والجرافين 2pboفنتون المتقدمة باستخدام األقطاب الكهربائية المعدلة بـ -الكترو رويدة نزيه عباس وعمار صالح عباس العراق. قسم الهندسة الكيمياوية, كلية الهندسة, جامعة بغداد, بغداد, الخالصة الكترو أكسدة في -عملية المستخدمة المتقدمة األساسية الكهروكيميائية األكسدة عمليات إحدى هي فنتون الكترو أكسدة عملية إجراء تم الصحي. الصرف مياه في ومشتقاته الفينول حرارة -معالجة درجة في فنتون ساعات. تم 6( لمدة تصل إلى 2مللي أمبير / سم 8، 6، 4، 2المختبر و بأستخدام كثافات تيار مختلفة ) ملي موالر من تركيز 0.4موالر كمحلول كهربائي داعم ، و استخدم 0.05استخدام كبريتات الصوديوم بتركيز ( الحديدية ترسيب fe2األيونات بواسطة المعدل الجرافيت من الكهربائية المعالجة خلية تتكون كمحفز. )+ أشارت النتائج إلى أن ع pbo2طبقة من لى سطحها كأنود وألياف كربون معدلة باستخدام الجرافين ككاثود. ساعات من 6تركيز الفينول يتناقص مع زيادة كثافة التيار ، والحد األدنى لتركيز الفينول المتحصل عليه بعد ن التركيز االولي للفينول بدءا م جزء في المليون 7.82يساوي 2مللي أمبير / سم 8التحليل الكهربائي عند تقريبا يساوي عند ppm 155الذي الفينول ألكسدة الحركية الدراسة من عليها المتحصل النتائج أظهرت . كثافات تيار مختلفة أن التفاعل يتبع حركية من الدرجة األولى. كما تم تقدير المعلمات النشطة مثل استهالك ت تيار مختلفة. أظهرت النتائج أن الزيادة في كثافة التيار أدت إلى زيادة الطاقة المحدد و الكفاءة الحالية بكثافا في استهالك الطاقة المحدد للعملية و انخفاض كفاءة التيار. .فينتون ، الجرافيت ، ألياف الكربون -مياه الصرف الصحي ، ملوثات الفينول ، أكسدة إلكترو :الدالة الكلمات available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol. 24 no.1 (march 2023) 97 – 103 eissn: 2618-0707, pissn: 1997-4884 *corresponding author: name: rwaida kaiser abdulmajeed, email: rwaida@gmail.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. different development scenarios to increase the production rates for fauqi oil field southeastern iraq rwaida kaiser abdulmajeed * petroleum engineering department, college of engineering, university of baghdad, iraq abstract the fauqi field is located about 50km north-east amara town in missan providence in iraq. fauqi field has 1,640 mmbbl stoiip, which lies partly in iran. oil is produced from both mishrif and asmari zones. geologically, the fauqi anticline straddles the iraqi/iranian border and is most probably segmented by several faults. there are several reasons leading to drilling horizontal wells rather than vertical wells. the most important parameter is increasing oil recovery, particularly from thin or tight reservoir permeability. the fauqi oil field is regarded as a giant field with approximately more than 1 billion barrels of proven reserves, but it has recently experienced low production rate problems in many of its existing wells. this study will concentrate on analyzing the asmari reservoir as the main production reservoir in this field for an oil gravity of 18 api. while, well (fq-8) has been selected as a pilot well to verify different development scenarios that could be taken to increase the reservoir production rate. the results show that both drilling lateral sections and performing the stimulation process in some reservoir intervals yield positive results to increase good productivity with different percentages. the lateral sections occasionally gave higher productivity than the stimulation process by (2-3) times. keywords: productivity, vertical well, multilateral, horizontal well, fauqi oilfield. received on 26/07/2022, received in revised form on 06/09/2022, accepted on 08/09/2022, published on 30/03/2023 https://doi.org/10.31699/ijcpe.2023.1.11 1introduction horizontal wells may be more productive than vertical wells drilled in the same formation because of the extensive exposure to the reservoir. therefore, it is anticipated that longer horizontal wells will produce more than shorter wells. that might not always be the case, though. the main uncertainty is whether a horizontal well's productivity will rise according to the well's length and horizontal section perforation rate [1]. due to the many benefits presented, horizontal well drilling has achieved widespread acceptance over the last decade. horizontal wells are primarily used to increase well productivity by increasing contact with reservoir rocks. from an economic perspective, increasing the area of contact with the reservoir will result in an increase in the well's productivity index. these findings suggest that longer horizontal wells are more productive, and that horizontal wells should be drilled as long as practicable [2]. an excellent and shining example of innovative technology applied to meet modern economic needs is the multilateral concept. actually, the idea of a multilateral well is not new. the first multilateral well was actually sunk in 1953 at a field in russia, and in 1997, over 35 multilaterals of various descriptions being drilled in the middle east [2]. due to two reason, including improved formation production and reduced rig operations and mobilization costs as a result of drilling multiple wells on the same piece of land or platform, horizontal drilling is a method to lower drilling operations costs of an oil field [3]. in other meaning, the petroleum industry is particularly interested in horizontal wells since they offer a convenient way to increase both production rate and recovery efficiency [4]. the parameters (well length, permeability ratio, reservoir thickness, skin factor, drainage radius, and well radius) were discovered to have an impact on the pressure drop between the well bore and the reservoir, which in turn effects the productivity index in horizontal wells [5]. the analytical method can be applied to provide the position of owc in all direction in horizontal wells [6]. fractures play an important role for fluid flow and well productivity in the asmari carbonates. currently the field is producing oil under primary recovery from two reservoirs: (i) the tertiary asmari carbonates and siliciclastics (151 mmbbl stoiip) and (ii) the cretaceous mishrif limestones (585 mmbbl stoiip). advanced software computer programs have been used to analyze the production history of 2005 for the well (fq-8) using rate time analysis software and to verify different development scenarios to increase the production rates using the advance well test analysis software. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:rwaida@gmail.com http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2023.1.11 r. k. abdulmajeed / iraqi journal of chemical and petroleum engineering 24,1 (2023) 97 103 98 2asmari formation characteristics [7] from top to bottom the asmari consists of a dolomitedominated subunit, a limestone subunit with intercalated several meter-thick sandstone complexes, a siliclastic subunit, and the carbonates of the middle/lower kirkuk. these subunits were deposited in different environments as reflected by their highly variable reservoir characteristics. 3development scenarios the productivity of the asmari wells varies greatly with a productivity index (pi) between 3 and 56. this large range is interpreted to be due to the combined heterogeneity in matrix and fracture properties. the causes for the reservoir heterogeneity are very poorly understood, results in severely limiting uncertainty management during the future field development [8]. the current production and perforation policy concerning the asmari and the mishrif reservoir is not evident. possibly, the production from the fauqi field could be significantly increased by optimizing the field development strategy. this reservoir consists also from unconsolidated sandstone, since the hydraulic fracturing may have excluded from the development scenarios. then only acid stimulation and drilling horizontal well sections are taken into consideration. the productivity provided by the lateral horizontal sections have been verified while penetrating some of the productive intervals to select the best section that has potential to provide more productivity. 4result and discussion 4.1. results of stimulating the productive intervals of the vertical well fig. 1 show the stimulation results for different interval lengths of the vertical well; this shows that thicker section provides higher sensitivity to stimulation and provide higher flow capacity than thin intervals. fig. 1. production increment in well fq – 8 using stimulation operations within its intervals fig. 2 and fig. 3 show the increment in the productivity index and the production rates respectively versus lateral section lengths in various expected vertical to horizontal permeability ratios. this indicates the high sensitivity of the thin beds to response with the lateral sections, but no effect for the vertical to horizontal permeability ratios to increase the productivity in such thin beds. hence, fig. 4 show the high response for the stimulation process with the lateral sections. fig. 2. productivity index vs. lateral section length drilled in (10 ft interval) for different 𝐾𝑅 values , skin =0 r. k. abdulmajeed / iraqi journal of chemical and petroleum engineering 24,1 (2023) 97 103 99 fig. 3. well production vs. lateral section length drilled in (10 ft interval) for different 𝐾𝑅 values , skin =0 fig. 4. well production vs. lateral section length drilled in (10 ft interval) for different 𝐾𝑅 values , skin =4 4.2. results of drilling horizontal section penetrating interval (b-b1) fig. 5 and fig. 6 show the increment in the productivity index and the production rates respectively versus lateral section lengths in various expected vertical to horizontal permeability ratios. the results indicate low sensitivity of the thicker beds to response with the lateral sections (approximately 0.26 stb/d/meter), in spite of it is still yields higher flow rate capacity than thin beds. moreover, the results show no considerable effect for the vertical to horizontal permeability ratios to increase the productivity in such thin beds. 4.3. results of drilling horizontal section penetrating interval (b2-c) fig. 7 and fig. 8 show the increment in the productivity index and the production rates respectively versus lateral section lengths in various expected vertical to horizontal permeability ratios. the results also indicate the low sensitivity of the thicker beds to response with the lateral sections, in spite of it is still yields higher flow rate capacity than thin beds. moreover, the results show small effect for the vertical to horizontal permeability ratios to increase the productivity in such thin beds especially in small lateral section lengths. fig. 1 show different response for the percentage productivity increment while drilling horizontal lateral sections that is ranging between (30-150 %) for the lateral section length of (3000 ft); hence, it could also be noticed that the thicker intervals provides the most increment in the productivity than thin intervals. fig. 9 show weak response in percentage productivity increment while stimulation activities for the various bed sections that is ranging between (10-40 %) for the stimulation value reach to (skin= 6); however, larger values of stimulation in sandstone formation could not be reached and so it is just stated theoretically between (-1 to -8). hence, it could also be noticed that the thicker intervals provide the most increment in the productivity than thin intervals. the results show that penetrating thicker formations yield for higher production rates than that of thin formations. moreover, it seems that the thicker formation is more sensitive to vertical to horizontal permeability ratios that thin interval sections. however, this sensitivity r. k. abdulmajeed / iraqi journal of chemical and petroleum engineering 24,1 (2023) 97 103 100 stills not considerable even while penetrating the section (b2-c) of 9m thickness. in fact, this results conform the primary results of weak communication may exist between the reservoir productive intervals. fig. 1 and fig. 9 shows that drilling lateral sections usually provides higher productivity increments than stimulation process, these results indicates that lateral sections provides productivity increments (2-3) times higher than stimulation activities may made in any of the reservoir interval sections. hence, it could be useful to mention that the theoretical results show in higher stimulation values greater than (skin = -8), the productivity of the stimulated sections reached that of the lateral sections greater than 2500 ft, but practically this could be difficult to be reached in weak sandstone formation to prevent quick sand production [9, 10]. this point could be extended to the damage may accompanying the drilling length lateral sections, because the horizontal wells are much more susceptible to damage than their vertical counterparts due to several number of reasons. fig. 5. productivity index vs. lateral section length drilled in (26 ft interval) for different 𝐾𝑅 values , skin =0 fig. 6. production rate vs. lateral section length drilled in (26 ft layer thick) for different 𝐾𝑅 values , skin =0 fig. 7. productivity index vs. lateral section length drilled in (29.5 ft interval) for different 𝐾𝑅 values , skin =0 r. k. abdulmajeed / iraqi journal of chemical and petroleum engineering 24,1 (2023) 97 103 101 fig. 8. production rate vs. lateral section length drilled in (29.5 ft interval) for different 𝐾𝑅 values , skin =0 fig. 9. the percentage production increments vs. stimulation value by the vertical well interval hence, fig. 10 show the percent increment of the productivity for well fauqi (8) against lateral section extensions within the main productive intervals of asmari reservoir. fig. 10. percentage productivity increment vs. lateral section length in different interval r. k. abdulmajeed / iraqi journal of chemical and petroleum engineering 24,1 (2023) 97 103 102 5conclusion 1due to uncertainty in the reservoir architecture and the presence of fractures in addition to un availability formation for the production history from iranian side, a detailed reservoir simulation study will be useful for accurate reservoir performance. 2it could be easily concluded a multilateral horizontal wells could be performed in formation intervals (bb1) and (b2-c) to achieve higher production capacity for this well using lateral sections of (2000-3000 ft). while increasing the horizontal section in the thin intervals like (a) has very low sensitivity to lateral section incremental as shown in fig. 10. nomenclature kr: vertical to horizontal permeability ratio, dimensionless. le: lateral section length of horizontal well, ft. owc: oil water contact. pi: productivity index, stb/d/psi. a, b-b1, b2-c: formation intervals. references [1] abdullah m. al-qahtani, and habib menouar" new correlations for optimizing horizontal wells completions", paper presented at the middle east oil show and conference, bahrain, march 1997, spe 37768-1997, http://doi.org/10.2118/37768-ms. [2] r.w. taylor, spe and rick russell "drilling and completing multilateral horizontal wells in the middle east", paper presented at the spe annual technical conference and exhibition, san antonio, texas, october 1997. spe 38759 – 1997, http://doi.org/10.2118/38759-ms. [3] hasan ali n., ayad a. alhaleem, “torque and drag forces problems in highly deviated oil well”, iraqi journal of chemical and petroleum engineering, vol. 9, no.3, sept. 2018, pp. 19-31, https://doi.org/10.31699/ijcpe.2018.3.3. [4] mohammed s.a., a. a. al-dabaj, and hassan a.h., “design of horizontal well program for ajeel field”, iraqi journal of chemical and petroleum engineering, vol. 15, no.1, mar. 2014, pp. 59-63. [5] ghanim m.f., maha r. abdulamir, “formulation of new equation to estimate productivity index of horizontal wells”, iraqi journal of chemical and petroleum engineering, vol. 15, no.2, jun. 2014, pp. 61-73. [6] jalal abdulwahid alsudani, “analytical model for detection the tilt in originally oil water contacts”, iraqi journal of chemical and petroleum engineering, vol. 15, no. 3, sept. 2014, pp. 51-60. [7] reservoir and fields development directorate ministry of oil, iraq. 2010. [8] jalal a. al-sudani, rwaida k. abdulmajeed, “analytical and numerical analysis for estimation hydrocarbon in place for fauqi oil field”, journal of petroleum research & studies, vol. 212, issue 6th, 2012. pp. 186-212, https://doi.org/10.52716/jprs.v3i2.85. [9] bert b. williams, john l. gidley, robert s. schechter "acidizing fundamentals" spe of aime, new york, 1979. [10] syed zeeshan jilani "experimental study of formation damage in horizontal wells", a thesis presented to the deanship of graduate studies king fahd university of petroleum and minerals, march 2000. https://doi.org/10.2118/37768-ms https://doi.org/10.2118/38759-ms https://doi.org/10.31699/ijcpe.2018.3.3 https://www.iasj.net/iasj/download/1a4da1cb1e07c67d https://www.iasj.net/iasj/download/1a4da1cb1e07c67d https://www.iasj.net/iasj/download/1a4da1cb1e07c67d https://www.iasj.net/iasj/download/1a4da1cb1e07c67d https://www.iasj.net/iasj/download/9f0ce25dc6a50423 https://www.iasj.net/iasj/download/9f0ce25dc6a50423 https://www.iasj.net/iasj/download/9f0ce25dc6a50423 https://www.iasj.net/iasj/download/9f0ce25dc6a50423 https://www.iasj.net/iasj/download/9f0ce25dc6a50423 https://www.iasj.net/iasj/download/740d4dea717483ff https://www.iasj.net/iasj/download/740d4dea717483ff https://www.iasj.net/iasj/download/740d4dea717483ff https://www.iasj.net/iasj/download/740d4dea717483ff https://www.iasj.net/iasj/issue/4206 https://doi.org/10.52716/jprs.v3i2.85 https://www.proquest.com/openview/f8d5c6b3c439e8216ac5fc3735d9aa3f/1?pq-origsite=gscholar&cbl=18750&diss=y https://www.proquest.com/openview/f8d5c6b3c439e8216ac5fc3735d9aa3f/1?pq-origsite=gscholar&cbl=18750&diss=y https://www.proquest.com/openview/f8d5c6b3c439e8216ac5fc3735d9aa3f/1?pq-origsite=gscholar&cbl=18750&diss=y https://www.proquest.com/openview/f8d5c6b3c439e8216ac5fc3735d9aa3f/1?pq-origsite=gscholar&cbl=18750&diss=y https://www.proquest.com/openview/f8d5c6b3c439e8216ac5fc3735d9aa3f/1?pq-origsite=gscholar&cbl=18750&diss=y r. k. abdulmajeed / iraqi journal of chemical and petroleum engineering 24,1 (2023) 97 103 103 شرق العراقتطوير تحليالت مختلفة لزيادة معدالت انتاج حقل فكة النفطي جنوب * عبدالمجيد رويدة قيصر ، العراقجامعة بغداد، كلية الهندسةقسم هندسة النفط، الخالصة كم شمال شرق مدينة العمارة في محافظة ميسان في العراق. هذا الحقل له 50يقع حقل الفكة حوالي من و من طبقة المشرف واالسمري. مليار برميل خزين نفطي والذي يمتد جزئيا داخل ايران. ينتج النفط 1640 يها واجد فالناحية الجيولوجية فأن حقل الفكة يتكون من قبة تقع على الحدود العراقية االيرانية والتي يحتمل ت لعامل هناك عدة أسباب تؤدي إلى حفر اآلبار األفقية بداًل من اآلبار العمودية. ا بعض التشققات والفواصل. ال فطي حق، ال سيما من نفاذية مكمن رقيقة أو ضيقة. يعتبر حقل ًفكة النتخالص النفطثر أهمية هو زيادة اساألك اض ، لكنه شهد مؤخًرا مشاكل انخفار برميل من االحتياطيات المؤكدةملي 1عمالًقا يحتوي على ما يقرب من رئيسي كمكمن أنتاجيهذه الدراسة ستركز على تحليل مكمن االسمري .معدل اإلنتاج في العديد من آباره الحالية ضحت أن النتائج أو ( لمالحظة طريقتين لزيادة االنتاجية.8ا.ب.أ(. كما أختير البئر )فكة 18لنفط ذو كثافة ) تاجية عملية حفر مقاطع أفقية وكذلك أجراء عمليات التنشيط في بعض المقاطع التكوينية تؤدي الى زيادة االن ( 3-2االفقية أعطى أعلى أنتاجية من عمليات التنشيط بحوالي ) وبنسب مختلفة. وبالطبع فأن حفر المقاطع مرة. .النفطي ةافقي، حقل فك عمودي، متعدد األطراف، بئر ، بئرةاالنتاجي الكلمات الدالة: available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol. 24 no.1 (march 2023) 41 – 50 eissn: 2618-0707, pissn: 1997-4884 *corresponding author: name: mohammed a. ahmed, email: 150093@uotechnology.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. asphaltene precipitation investigation using a screening techniques for crude oil sample from the nahr-umr formation/halfaya oil field mohammed a. ahmed a, b, *, ghassan h. abdul-majeed a, and ali k. alhuraishawy c a petroleum engineering department, college of engineering, university of baghdad, baghdad, iraq b petroleum technology department, university of technology, iraq c ministry of oil, iraq abstract many oil and gas processes, including oil recovery, oil transportation, and petroleum processing, are negatively impacted by the precipitation and deposition of asphaltene. screening methods for determining the stability of asphaltenes in crude oil have been developed due to the high cost of remediating asphaltene deposition in crude oil production and processing. the colloidal instability index, the asphaltene-resin ratio, the de boer plot, and the modified colloidal instability index were used to predict the stability of asphaltene in crude oil in this study. the screening approaches were investigated in detail, as done for the experimental results obtained from them. the factors regulating the asphaltene precipitation are different from one well to another, from the highpressure-temperature reservoir to surface conditions. all these factors must be investigated on a case-by-case basis. because the halfaya oil field is still developing its petroleum sector, modelling, and forecasting the phase behavior and asphaltene precipitation is crucial. this work used crude oil bottom hole samples with an api of equal to 27 from a well in the halfaya oil field/nahr-umr formation to create a thermodynamic model using multiflash software. the data included the compositional analysis, the pvt data, and reservoir conditions. the thermodynamic model of asphaltene phase behavior was proposed using the cubic-plus association equation of state. all the screening techniques' results revealed the presence of an asphaltene precipitation issue (asphaltene unstable), which was confirmed by a thermodynamic fluid model. the aim of this paper is to predict the problem of asphaltene precipitation so that future proactive remedial methods can be developed to decrease the time and expense associated with it. keywords: asphaltene, precipitation, screening methods, cii, multiflash software. received on 15/07/2022, received in revised form on 10/09/2022, accepted on 12/09/2022, published on 30/03/2023 https://doi.org/10.31699/ijcpe.2023.1.6 1introduction fossil fuels, such as oil and gas, cover a significant portion of global energy needs. according to the us energy information administration, global energy consumption would increase by 56% between 2010 and 2040. because we've ran out of easy oil, the oil and gas industry now has to produce oil and gas in unusual and challenging environments, such as deep waters and difficult-to-reach reservoirs. implementing a comprehensive flow assurance program, that is, ensuring continuous and cost-effective production and flow of oil and gas to refinery, is one of primary difficulties in the petroleum production [1]. asphaltene has been a major topic in study over the last few decades; yet, oil corporations continue to have issues with asphaltene deposition, prompting both academics and industry to work together to solve the problem. asphaltenes are a polydisperse blend of crude oil's heaviest and greatest polarizable fractions [2]. bitumen, crude oil, asphalts, and tar-mat all include asphaltenes. asphaltenes are characterized in current operations by their solubility, being entirely soluble in the aromatic solvents like toluene, benzene, but insoluble in light paraffinic solvent like n-pentane (normal-c5) or nheptane (n-c7). the molecular weight, structure, and other features of the asphaltenes formed vary significantly depending on the normal alkane employed to precipitate them. the polydisperse nature of asphaltenes accounts for this variation. from the literature survey, fig. 1-a and b illustrate the separation of asphaltenes from the identical crude oil sample using two distinct precipitants: normal pentane and normal heptane [3]. these figures, on the other hand, show pure asphaltenes extracted from an oil sample in the lab. separated asphaltenes are not pure during oil production and appear as a second liquid phase, as depicted in fig. 2. precipitation is defined by zendehboudi et al [4], as the production of the solid state from the liquid phase, whereas deposition is definite as the adhesion of the solid phase to the reservoirs or wall of wellbores, which normally happens after precipitation. asphaltene may also form flocculation, which are dense clusters of asphaltene [5, 6]. because the flocculation has a high density, they http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:150093@uotechnology.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2023.1.6 m. a. ahmed et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 41 50 42 tend to deposit and fill the reservoir's pore throat [7-9]. several parameters/variables impact asphaltene destabilization (asphaltene precipitation and asphaltene deposition), including temperature, pressure, mixture characteristics, the quantity of precipitation. as a result of the changes in thermodynamic parameters, solid aggregation may emerge. in compared to other thermodynamic and process factors/characteristics, it has been experimentally established that pressure has the greatest impact on asphaltene precipitation [10]. fig. 1. asphaltenes separate from the same crude oil sample in the laboratory, using n-c5 (a) and (b) n-c7 [3] fig. 2. asphaltene sample was extracted from a different source without any treatment [3] because of its capacity to precipitate, deposit, and so impede the continual production of oil from subsurface reserves, asphaltene is described as the cholesterol of crude oil [11]. asphaltene precipitation and deposition may negatively affect industrial systems' efficiency (and/or profitability), both upstream and downstream. asphaltene precipitation and deposition can have negative impacts such as pore throat blockage, altered reservoir wettability, and decreased reservoir permeability. aside from clogging flow facilities, solids growth in storage tanks, and fouling of safety valves, asphaltene precipitation or deposition in the downstream portion also causes these issues. additionally, asphaltene may reduce catalyst conversion and activity, which may cause coke to build up in refineries [12]. numerous methods for detecting asphaltene deposition in conventional oil reservoirs have been proposed, including the de boer plot [13], the asphaltene/resin (a/r) ratio method [14], the colloidal instability index (cii) [15], the modification colloidal instability index (mcii) [16], the acoustic resonance technique, the filtration method, and the light scattering technique. to control asphaltene deposition, two types of strategies have been devised and applied: inhibition and treatment. adjustment of oil production conditions and parameters, as well as the use of chemical inhibitors, are examples of inhibitor strategies. the treatment procedures include biological, chemical, thermal, mechanical, and external strategies [12]. the halfaya oilfield is located in the southern mesopotamian basin of iraq. the basin is also known as the near platform flank of the mesopotamian foredeep. similar to most fields in iraq, the halfaya oilfield is a nw-se trending anticline, about 30km long and 10km wide. warm, shallow water carbonates from the oligocene to early miocene and early to late cretaceous, with sporadic clastic influence, particularly from the early cretaceous and late miocene, make up the majority of the petroleum system. to date, 9 oil-bearing carbonate and sandstone reservoirs and 14 oil systems have been discovered in the tertiary and cretaceous and the burial depth is 1900m–4400m. according to the development plan, halfaya oil field is divided into 7 development reservoir strata. the issue of asphaltene precipitation and deposition in the halfaya oilfields/nahr-umr formation has received a lot of attention in the past years because much field evidence during logging jobs indicated the existence of an asphaltene issue in this formation's crude oil by detecting the asphaltene suspensions on the bottom hole tools. the main goal of this research was to forecast the precipitation of asphaltene in the hf-oil field using crude oil composition analysis, "screening techniques," which rely on sample analysis and reservoir data, and validation of these techniques using multiflash software at reservoir and surface conditions. 2experimental work 2.1. materials a. reservoir data experimental and reservoir data were used in this study to simulate asphaltene precipitation. the simulation program for modeling uses the experimental data from compositional analysis and fluid behavior as input. for this investigation, a well in the maysan governorate/halfaya oil field was chosen, and oil samples were collected from there. the name and specific location of this well are not published in this paper for reasons of secrecy. the well is referred to as hf-x in this study. m. a. ahmed et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 41 50 43 table 1 shows the reservoir data collected from the ministry of oil-iraq. table 1. reservoir data parameters it's value formation nahr-umr reservoir fluid oil reservoir pressure , psi 5114 psig reservoir temperature, fº 243 fº saturation pressure @ 243 fº 1863 psig wellhead pressure 893 psig wellhead temperature 91 °f choke size 32/64 sample bhs (live oil) sampling depth 3500 m b. sara analysis saturates hydrocarbon-aromatic-resin-asphaltene (sara) crude oil analysis is a physical fractionation method which is based on the hydrocarbon components' solubility and polarity in different solvents and adsorbent materials. it is the most often used method for determining the composition of crude oil [17]. it divides the crude oil into four components. each of these sub fractions is made up of chemicals with comparable properties [18-19]. n-paraffins, iso-paraffins, and cycloparaffins are saturates. aromatic hydrocarbons are benzene derivatives. resins and asphaltenes are aromatic ring and polycyclic compounds with certain aliphatic side chains that have a relatively high molecular weight. sara analysis by high-performance liquid chromatography (hplc) separates, identifies, and quantifies these fractions. fig. 3 shows a procedure of the sara analysis technique for distinguishing between crude oil's components. 1 cm3 of the crude oil is dissolved in n-heptane to make up the sample. the insoluble fraction is retained on the filter after vacuum. the filtered material is weighed and classified as asphaltene. the filtrated maltenes are then sealed in chromatographic vials and repeatedly injected into the hplc. at this stage, the separation between saturated and aromatic fractions occurs. following that, after separation in the column, the sample travels to the uv-vis and refractive index detectors, which give the analytical response. due to their high polarity, the resins are trapped inside the hplc column. to elute that fraction, the columns are back in using a dichloromethane/n-heptane mobile phase. the solution is collected in vials, and the solvent is evaporated under inert gas flow. the resin weight is then calculated by the weight difference. the final results are given the weight percentage of each fraction and the ratios between fractions (table 2). c. compositional analysis of reservoir fluid (bhs) the measurement of the distribution of hydrocarbons and other components contained in samples of oil and gas is known as compositional analysis. to assess the breakdown of the sample's components, samples are studied using current chromatography methods. gas compositions are determined by gas chromatography (gc) conforming to a modified gpa standard 2286-95 method. this standard allows separation and quantification of hydrocarbons from c1 through c15 + as well as h2, n2, co2 and h2s. atmospheric liquid compositions are determined by gas chromatography (gc) conforming to an 'in-house' core laboratories method. this methodology allows separation and quantification of hydrocarbons from c1 through c36 + (core laboratories). table 3 shows the compositional analysis of reservoir fluid sample as c36 + and plusfraction properties. the impact of increasing or decreasing the mole fraction of each component in the crude oil mixture is explored using asphaltene definition and depending on its solubility approach. asphaltene becomes unstable (precipitation occurs) when the mole fractions of light components are high (such as: c1, c2, co2, n2, etc.), but the opposite occurs with heavy components (such as: pseudo-component). the colloidal theory supports the idea that increasing the amount of resin in the mixture improves the stability of the asphaltene and minimizes the risks of precipitation. fig. 3. sara fractionation flowchart [19] table 2. sara fraction fractions wt % saturate hydrocarbon 63.23 wt % aromatic 24.36 wt % resin 5.11 wt % asphaltene 7.3 wt % hydrocarbons ratio (saturates / aromatics) 2.6 non hydrocarbons ratio (resins /asphaltenes) 0.7 hydrocarbons / non hydrocarbons ratio 7.06 2.2. theory and literature survey a. de-boer plot de boer et al. [13] devised a screening approach for determining the asphaltene precipitation tendency. the primary factors are the hildabrand solubility variables and molar volume, and the model is based on the floryhuggins theory. according to de boer et al., the oil's parameters/properties may be correlated to its in-situ density. they were discovered that lowering pressure reduces the solubility up to the bubble point, whereas lowering the pressure below the bubble point improves the solubility of asphaltene [13]. as a consequence, they m. a. ahmed et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 41 50 44 proposed three zones inside the differential pressure of initial & bubble point conditions vs solubility at the initial density of the oil to demonstrate where the precipitation possibility is highest [13]. the three zones, namely: (a) severe problems, (b) possible problems, and (c) no problems. table 3. the compositional analysis of the reservoir fluid sample to c36 + component recombined fluid mole % 2h 0 s2h 0 2co 1.01 2n 0.23 1c 26.84 2c 7.24 3c 6.01 4c-i 1.25 4c-n 3.6 )entanep-( neo5c 0.01 5c -i 1.82 5c -n 2.48 6c 3.81 )pentane-c-( m 7c 0.55 (benzene)7 c 0.1 (cyclohexane) 7c 0.31 (heptanes) 7c 3.08 )hexane-c-(m 8c 0.53 (toluene) 8c 0.33 (octanes) 8c 3.22 )zeneben-(e 9c 0.23 )ylenex-(m/p 9c 0.51 )exylen-(o 9c 0.2 (nonanes) 9c 2.7 )tmb-(1,2,4 10c 0.24 (decanes) 10c 2.95 11c 2.82 12c 2.41 13c 2.22 14c 1.85 15c 1.77 16c 1.56 17c 1.32 18c 1.24 19c 1.2 20c 1.04 21c 0.92 22c 0.83 23c 0.75 24c 0.68 25c 0.61 26c 0.56 27c 0.51 28c 0.49 29c 0.46 30c 0.44 31c 0.43 32c 0.38 33c 0.35 34c 0.35 35c 0.29 + 36c 5.27 total 100% +36molecular weight of c (g mol-1) 988.1 )3-at 60°f (g cm +36density of c 1.0673 b. asphaltene resin (a/r) ratio approach jamaluddin et al [14] were the first to suggest the asphaltene-resin ratio technique. the model was then modified to identify two separate zones: stable and unstable, with the unstable zone being more prone to asphaltene precipitation due to the asphaltene to resin weight ratio [4]. c. colloidal instability index (cii) the crude oil is treated as a colloidal solution including the pseudo-components saturates, aromatics, resins, and asphaltenes, according to the colloidal instability index. the cii is defined as the mass ratio of asphaltenes and their flocculants (saturates) to their peptizes (resins and aromatics) in crude oil, and it indicates the stability of asphaltenes in terms of these pseudo-components [20]: cii = asphaltene wt%+saturate wt% aromatic wt%+resin wt% (1) the weight percentages derived from sara analysis are used in the colloidal instability index just as they are in the asphaltene–resin ratio. the cii has been used to evaluate the stability of asphaltenes in crude oil-solvent mixtures. it has been demonstrated that indices related to the cii, such as the saturates-peptizers ratio (saturates/aromatics resins), or the asphaltene-peptizers ratio (asphaltenes/aromatics resins), may be used to correlate the stability of asphaltenes in crude oils and their mixture. based on the vast database of crude oils, empirical evidence shows that values of 0.9 and higher suggest an oil with unstable asphaltenes, while values below 0.7 indicate an oil with stable asphaltenes; values between 0.7 and 0.9 indicate an oil with questionable asphaltene stability [20]. d. modified colloidal instability index (mcii) in order to reduce the cost of conducting sara analysis on the one hand and rely on data with reservoir conditions on the other, akram hamoudi et al [16] modified the cii equation by using pvt data (compositional analysis by chromatograph) instead of sara analysis. the new equation named as the modified cii (mcii) as shown in eq. 2. they employed three wells from iraq's kurdistan region in their research. after comparing the results to the original cii equation and using the de boer plot, they decided that this modification was acceptable. mcii = 𝐿𝑐+𝑀𝑐 𝐻𝑐+𝑁𝑐 (2) where: mc = mole % of medium hydrocarbons, lc is a mole % of light hydrocarbons, nc is a mole % of nonhydrocarbons, hc is a mole % of heavy hydrocarbons.  if mcii < 0.7, no asphaltene problem.  if mcii > 0.9, asphaltene problem.  if 0.7 < mcii< 0.9, may be a problem with asphaltene. the reservoir fluid components identified by pvt analysis can replace sara fractions. since the components are expressed as mole percentages and add up to 100, the inputs to the equation agree with the original one, but we still need to assign each component m. a. ahmed et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 41 50 45 to one of the sara elements. the equivalent sara percentages for each component are shown in table 4. the definition of each constituent in the sara analysis served as the basis for the classification, which is based on molecular weight. for instance, aromatics have the lowest molecular weight, but asphaltenes have the most. the phrase "non-hydrocarbons" has been used to make up for the lost resin weight % because there are no resins. this equation may be changed to produce outcomes that are similar to the test data since the sum of the experimental data and the sum of the cii inputs both equal 100 [16]. table 4. sara fractions related to hydrocarbon components the name component group sara corresponding light component c1-c5 aromatices medium component c6-c8 saturates heavy component c9 + asphaltene non-hydrocarbon co2, h2, n2,h2s resins raad and ayad al-haleem [21] used the mcii model to investigate the asphaltene stability of crude oil samples from buzurgan oil field. after comparing the mcii value to the previous study of this oil field, they found that it confirms the problem of asphaltene deposition in this oil field, demonstrating the accuracy of this equation in predicting asphaltene precipitation and providing more reliability to be used in subsequent studies. 2.3. asphaltene phase envelope (ape) determination a software called multiflash was used to forecast the asphaltene phase envelope for the nahr-umr crude oil samples. the precipitation of asphaltene during the depletion of a reservoir is using a phase behavior that integrates an advanced solid thermodynamic model. this program enables modeling of up to three fluid phases that are in equilibrium with the solid. multiflash employs the cubic-plus association cpa-eos, which is the most widely used method for predicting oil and gas phase states. eos is widely used by multiflash to determine the phase behavior of reservoir fluids. it also calculates and predicts the interaction coefficients that are used to account for interactions between molecules that are not related. fig. 4 depicts the basic processes involved in modeling an asphaltene precipitation model with multiflash. fig. 4. the flow chart of asphaltene precipitation modeling 3results and discussion a. investigation of asphaltene stability using de boer plot de boer et al [13] worked on a variety of samples, both experimental and theoretical, all over the world. they were able to create a plot that is currently adopted by the majority of experts. first, since the samples in de boers' plot are versatile, and second, because the plot considers reservoir conditions. after projecting this data onto the plot (fig. 5) with reservoir pressure = 5114 psig, bubble point pressure = 1863 psig, and fluid density in the halfaya oil field/nahrumr formation = 0.738 g/cm3, the result indicated that there was a chance of asphaltene precipitation (possible problem) in the hf-x well. b. investigation of asphaltene stability using asphaltene -resin (a/r) ratio sara fractionation, which is an analytical technique of dividing oil into four parts according to their polarity: saturates, aromatics, resins, and asphaltenes. it is one of the finest ways to describe an oil mixture. the sara fraction values from an oil sample recovered from well hf-x are shown in table 2. the weight percentage of asphaltene is 7.3 wt%, whereas the weight percentage of resin is 5.11 wt%. the results indicate that the asphaltene is unstable as well as the possibility of asphaltene precipitation, as shown in fig. 6. m. a. ahmed et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 41 50 46 c. investigation of asphaltene stability using modified colloidal instability index (mcii) to use eq. 2, we must first compute the mole percentage of each group (lc, mc, nc, & hc) for well hf-x, as given in table 3 and table 4. table 3 was divided into four groups, as indicated in table 5. mcii = 𝐿𝑐+𝑀𝑐 𝐻𝑐+𝑁𝑐 = 49.25 +11.93 37.58 +1.24 = 1.576 since mcii = 1.576 (i.e. ˃ 0.9), then the asphaltene is unstable (asphaltene problem). table 5. classification of components corresponding to sara analysis component recombined fluid mole % the group mole% summation for each group h2 0 nc (non-hydrocarbons) nc = 1.24 h2s 0 co2 1.01 n2 0.23 1c 26.84 lc (light hydrocarbons) lc = 49.25 2c 7.24 3c 6.01 4c-i 1.25 4c-n 3.6 )ntanepe-( neo5c 0.01 5c -i 1.82 5c -n 2.48 6c 3.81 mc (medium hydrocarbons) )pentane-c-( m 7c (benzene)7 c (cyclohexane) 7c (heptanes) 7c 0.55 0.1 0.31 mc = 11.93 3.08 )hexane-c-(m 8c (touene) 8c (octanes) 8c 0.53 0.33 3.22 )enebenz-( e 9c )lenexy-( m/p 9c xylene)-( o9 c ( nonanes) 9c 0.23 hc ( heavy hydrocarbons) hc = 37.58 0.51 0.2 2.7 tmb)-(1,2,4 10c ( decanes) 10c 0.24 2.95 11c 2.82 12c 2.41 13c 2.22 14c 1.85 15c 1.77 16c 1.56 17c 1.32 18c 1.24 19c 1.2 20c 1.04 21c 0.92 22c 0.83 23c 0.75 24c 0.68 25c 0.61 26c 0.56 27c 0.51 28c 0.49 29c 0.46 30c 0.44 31c 0.43 32c 0.38 33c 0.35 34c 0.35 35c 0.29 + 36c 5.27 100% 100% m. a. ahmed et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 41 50 47 fig. 5. hf-x well examination by de boers plot for predicting asphaltene precipitation, de boer plot from [13] fig. 6. hf-x well examination by asphaltene/resin relationship for predicting asphaltene precipitation, a/r plot from [4] d. investigation of asphaltene stability using colloidal instability index (cii) this approach uses eq. 1 with a saturated weight percent of 63.23 wt percent, an aromatic weight percent of 24.36 wt percent, a resin weight percent of 5.11 wt percent, and an asphaltene weight percent of 7.3 (as given in table 2). because the value of cii is 2.39, and it is greater than 0.9, the findings indicate that there is a possibility of asphaltene precipitation (unstable asphaltene). this can be illustrated by fig. 7. cii = asphaltene wt%+saturate wt% aromatic wt%+resin wt% = 7.3+ 63.23 24.36+5.11 = 2.39 because cii= 2.93 (i.e. ˃ 0.9) again there is an asphaltene problem. e. validation of screening techniques with a thermodynamic model we plot the asphaltene phase envelope (ape) and project the reservoir and wellhead conditions on it after completing the steps indicated in fig. 4. then, from the point of reservoir conditions to the point of wellhead conditions, we construct a line. we can see that the line passes through the three-phase region (ape), which indicates that once the pressure decreases below the aop threshold, there is a probability of asphaltene precipitation (see fig. 8). fig. 7. hf-x well examination by cii for predicting asphaltene precipitation, cii plot from [20] fig. 8. phase diagram of fluid and asphaltene as mentioned in table 6, the results of the four screening methods may now be compared to the thermodynamic fluid model. because these approaches indicate that asphaltene is unstable, there is a high probability that the problem of asphaltene precipitation will occur as production time and pressure drop. as a result, we require treatments to mitigate the risks posed by asphaltene deposition, whether in the reservoir or in the wellbore. table 6. summary of results the well / formation / field hf-x / nahr-umr / halfaya oil field de boer technique possible problem (asphaltene precipitation) asphaltene -resin (a/r) ratio the asphaltene is unstable colloidal instability index (cii) unstable asphaltene (asphaltene problem) modified colloidal instability index (mcii) unstable asphaltene (asphaltene problem) thermodynamic model using cpaeos by multiflash high probability of asphaltene precipitation m. a. ahmed et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 41 50 48 4conclusions the following conclusions could be drawn from this study:  asphaltene stability in dead oil and live oil was predicted using investigation techniques. data from real-world production systems and simulations of thermodynamic fluid models back up the indicators' efficacy. the need of accurate sara data was underlined since it allows for more accurate calculation of asphaltene stability.  using multiflash software, which employs eos, the study demonstrated critical stages and methods necessary to complete a phase behavior model for asphaltene in wells in the maysan governorate. to model asphaltene, the model employed data from chromatograph and pvt analysis.  all techniques demonstrated that asphaltene deposition is a real issue in the halfaya oil field. nomenclature a/r = asphaltene/resin ratio aop = asphaltene onset pressure ape = asphaltene phase envelope cii = colloidal instability index cpa = cubic-plus association eos= equation of state hc = mole % of heavy hydrocarbons hf = halfaya oil field lc = mole % of light hydrocarbons mc = mole % of medium hydrocarbons mcii = modified colloidal instability index nc = mole % of non-hydrocarbons sara= saturates aromatic resin asphaltene references [1] a. sieminski & administrator," energy information administration," international energy outlook, 2016. [2] m. tavakkoli, s. panuganti, v. taghikhani, m. pishvaie and w. chapman, "understanding the polydisperse behavior of asphaltenes during precipitation", fuel, vol. 117, pp. 206-217, 2014. https://doi.org/10.1016/j.fuel.2013.09.069. [3] j.s. buckley, and j.x. wang, personal communication, 2006. [4] s. zendehboudi, a. shafiei, a. bahadori, l. james, a. elkamel and a. lohi, "asphaltene precipitation and deposition in oil reservoirs – technical aspects, experimental and hybrid neural network predictive tools", chemical engineering research and design, vol. 92, no. 5, pp. 857-875, 2014. https://doi.org/10.1016/j.cherd.2013.08.001. [5] l. boucheron et al., "stress relaxation in quasi-twodimensional self-assembled nanoparticle monolayers", physical review e, vol. 97, no. 5, 2018. https://doi.org/10.1103/physreve.97.052803. [6] s. fakher, m. ahdaya, m. elturki and a. imqam, "an experimental investigation of asphaltene stability in heavy crude oil during carbon dioxide injection", journal of petroleum exploration and production technology, vol. 10, no. 3, pp. 919-931, 2020. https://doi.org/10.1007/s13202-019-00782-7. [7] h. rassamdana, b. dabir, m. nematy, m. farhani and m. sahimi, "asphalt flocculation and deposition: i. the onset of precipitation", aiche journal, vol. 42, no. 1, pp. 10-22, 1996. https://doi.org/10.1002/aic.690420104. [8] e. khamehchi, m. shakiba and m. ardakani, "a novel approach to oil production optimization considering asphaltene precipitation: a case study on one of the iranian south oil wells", journal of petroleum exploration and production technology, vol. 8, no. 4, pp. 1303-1317, 2018. https://doi.org/10.1007/s13202-017-0409-0. [9] m. ihtsham hashmi and b. ghosh, "dynamic asphaltene deposition control in pipe flow through the application of dc potential", journal of petroleum exploration and production technology, vol. 5, no. 1, pp. 99-108, 2015. https://doi.org/10.1007/s13202-014-0113-2. [10] j. sayyad amin, s. alimohammadi and s. zendehboudi, "systematic investigation of asphaltene precipitation by experimental and reliable deterministic tools", the canadian journal of chemical engineering, vol. 95, no. 7, pp. 1388-1398, 2017. https://doi.org/10.1002/cjce.22820. [11] s. kokal and s. sayegh, "asphaltenes: the cholesterol of petroleum", in middle east oil show, all days, 1995. https://doi.org/10.2118/29787-ms. [12] s. alimohammadi, s. zendehboudi and l. james, "a comprehensive review of asphaltene deposition in petroleum reservoirs: theory, challenges, and tips", fuel, vol. 252, pp. 753-791, 2019. https://doi.org/10.1016/j.fuel.2019.03.016. [13] r. de boer, k. leerlooyer, m. eigner and a. van bergen, "screening of crude oils for asphalt precipitation: theory, practice, and the selection of inhibitors", spe production &amp; facilities, vol. 10, no. 01, pp. 55-61, 1995. https://doi.org/10.2118/24987-pa. [14] a. jamaluddin, j. nighswander, b. kohse, a. el mahdi, m. binbrek and p. hogg, "experimental and theoretical assessment of the asphaltene precipitation characteristics of the sahil field under a proposed miscible gas injection scheme", spe 87292 presented at the spe conf. and exh., 2000. https://doi.org/10.2118/87292-ms. [15] a. yen, y. yin and s. asomaning, "evaluating asphaltene inhibitors: laboratory tests and field studies", spe -65376-ms presented at the spe international symposium on oil field chemistry, houston, texas, 2001. https://doi.org/10.2118/65376ms. https://www.eia.gov/pressroom/presentations/sieminski_09282016.pdf https://www.eia.gov/pressroom/presentations/sieminski_09282016.pdf https://www.eia.gov/pressroom/presentations/sieminski_09282016.pdf https://doi.org/10.1016/j.fuel.2013.09.069 https://doi.org/10.1016/j.cherd.2013.08.001 https://doi.org/10.1103/physreve.97.052803 https://doi.org/10.1007/s13202-019-00782-7 https://doi.org/10.1002/aic.690420104 https://doi.org/10.1007/s13202-017-0409-0 https://doi.org/10.1007/s13202-014-0113-2 https://doi.org/10.1002/cjce.22820 https://doi.org/10.2118/29787-ms https://doi.org/10.1016/j.fuel.2019.03.016 https://doi.org/10.2118/24987-pa https://doi.org/10.2118/87292-ms https://doi.org/10.2118/65376-ms https://doi.org/10.2118/65376-ms m. a. ahmed et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 41 50 49 [16] a. humoodi abdulwahab, b. aziz and d. khidhir, "a study of asphaltene precipitation problem in some wells in kurdistan region", issue six, vol. 4, no. 6, pp. 27-36, 2020. https://doi.org/10.25079/ukhjse.v4n1y2020.pp27-36. [17] d. powers, "characterization and asphaltene precipitation modeling of native and reacted crude oils", university of calgary, 2014. http://dx.doi.org/10.11575/prism/25258. [18] h.yingshi, y. hongqing, z. xiaoping, j. guitarte, x. chenggang, l. weimin, c. xiang, and g. hongzhi, "cased hole formation testing in challenging operational conditions reveals reservoir fluids distribution: south china sea case study", european association of geoscientists & engineers, iptc international petroleum technology conference, 2012. https://doi.org/10.3997/22144609-pdb.280.iptc14841_nopw. [19] v. sieben et al., "optical measurement of saturates, aromatics, resins, and asphaltenes in crude oil", energy &amp; fuels, vol. 31, no. 4, pp. 36843697, 2017. https://doi.org/10.1021/acs.energyfuels.6b03274. [20] s. asomaning, "test methods for determining asphaltene stability in crude oils", petroleum science and technology, vol. 21, no. 3-4, pp. 581590, 2003. https://doi.org/10.1081/lft-120018540. [21] r. hasan and a. a. al-haleem, "modifying an equation to predict the asphaltene deposition in the buzurgan oil field", iraqi journal of chemical and petroleum engineering, vol. 21, no. 4, pp. 49-55, 2020. https://doi.org/10.31699/ijcpe.2020.4.6. https://doi.org/10.25079/ukhjse.v4n1y2020.pp27-36 http://dx.doi.org/10.11575/prism/25258 https://doi.org/10.3997/2214-4609-pdb.280.iptc14841_nopw https://doi.org/10.3997/2214-4609-pdb.280.iptc14841_nopw https://doi.org/10.1021/acs.energyfuels.6b03274 https://doi.org/10.1081/lft-120018540 https://doi.org/10.31699/ijcpe.2020.4.6 m. a. ahmed et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 41 50 50 باستخدام طرق الغربلة لعينة نفط من تكوين نهر عمر نالتحقق من ترسب األسفلتي /حقل الحلفاية النفطي 3 وعلي خيون الحريشاوي ،1 غسان حميد عبدالمجيد ،، *2، 1 محمد عبد هللا احمد قسم هندسة النفط، كلية الهندسة، جامعة بغداد، العراق 1 التكنولوجية، العراققسم تكنولوجيا النفط، الجامعة 2 وزارة النفط العراقية، العراق 3 الخالصة ، لنفطانقل له تأثير ضار على عدد من عمليات النفط والغاز، بما في ذلك استخراج النفط، و ينترسب األسفلت ات ير تقنيتطو ، فقد تم األسفلتين في إنتاج النفط الخام ا للتكلفة الكبيرة لمعالجة ترسبومعالجة البترول. نظر لى إإلسفلت ادام مؤشر عدم االستقرار الغرواني، ونسبة لتقييم استقرار األسفلت في النفط الخام. تم استخلغربلة ا الخام في ، ومؤشر عدم االستقرار الغرواني المعدل للتنبؤ باستقرار األسفلتين في النفطde boerرسم ، و الراتنج تختلف تفصيل باإلضافة إلى النتائج التجريبية التي تم الحصول عليها.بال غربلةطرق ال شرحهذه الدراسة. تم روف ظغط ودرجة الحرارة إلى ، ومن الخزانات عالية الضترسيب األسفلتين من بئر إلى بئر العوامل التي تنظم في طور النفطي ال يزال ةعلى أساس كل حالة على حدة. نظر ا ألن حقل حلفاي دراستها، ويجب السطح لعمل اهذا في األسفلتين أمر بالغ األهمية. استخدم ترسب الطور و، فإن وضع النماذج والتنبؤ بسلوك ويرالتط ي ألنشاء نموذج ديناميك طبقة نهر عمر/النفطي ةبئر في حقل حلفاي قاع من (api =27) لنفط الخاملعينات م ظروف المكمن. ت، و pvt، تحليل لتركيبيبيانات التحليل اال. تضمنت multiflashحراري باستخدام برنامج لغربلة اتقنيات . تشير جميع نتائج cpaباستخدام معادلة الحالة التكعيبية األسفلتين راقتراح نموذج لسلوك طو ع ، والتي تم تأكيدها باستخدام نموذج المائسفلتين )األسفلتين غير المستقر(إلى وجود مشكلة ترسيب األ جةمعال ر طرق تطوي بحيث يمكنالديناميكي الحراري. تهدف هذه الورقة إلى التنبؤ بمشكلة ترسيب األسفلتين وتقليل الوقت والتكلفة المرتبطة بها. لةة للمشكاستباقي .multiflash، برنامج االستقرار الغروانيعدم ، مؤشرالغربلة، طرق األسفلتين، الترسيبالكلمات الدالة: available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol. 24 no.1 (march 2023) 79 – 88 eissn: 2618-0707, pissn: 1997-4884 *corresponding author: name: ali k. al-delfi, email: ali.hashim2008m@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. experimental study to investigate the effect of polyacrylamide gel to reduce the lost circulation ali k. al-delfi a, *, faleh h. m. al-mahdawi a, yasir mukhtar b, and yousif eltahir bagadi c a petroleum engineering department, college of engineering, university of baghdad, iraq b university of petroleum, beijing, china c university of science and technology, sudan abstract one of the challenging issues encountered during drilling operations is the lost circulation. numerous issues might arise because of losses, such as wasting of time and higher drilling cost. several types of lost circulation materials have been developed and are being used to limit mud losses and avoid associated issues. each solution has benefits and drawbacks. in this study, a core flooding test was performed to study the effectiveness of polyacrylamide (pam) granular gel on the reduction of the circulation lost. one common type of fracture characteristic is fractures with tips, commonly known as partially open fracture (pof). however, pam gel therapy in pofs received little attention in prior research. models of partly open fractures were built using a cylindrical core. a series of processes are performed on a core to get a pof model. overall, the pam gel can decrease plug permeability, making it a useful material for lost circulation. the results indicate that the polyacrylamide granular gel can decrease the permeability up to 193 times. keywords: lost circulation, lost circulation materials (lcm), polyacrylamide, pam. received on 16/08/2022, received in revised form on 11/09/2022, accepted on 12/09/2022, published on 30/03/2023 https://doi.org/10.31699/ijcpe.2023.1.9 1introduction lost circulation is one of the most frequently discussed issues that has attracted industry-wide attention. it happens when drilling mud that is pumped through the drill string doesn't come back up to the surface. instead, it goes into the formation that is being drilled. the cost of losses on well construction is estimated to be between two and four billion dollars per year in wasted drilling mud, missed productive time, and preventive lost materials [1]. when losses occur, non-productive time (npt) rises. due to a loss of circulation, npt is wasted attempting to re-establish circulation. the expenditures of the lost drilling mud, as well as the treatment necessary to correct the problem, are included in the economic effect of losses. the yearly cost of lost circulation difficulties, including material costs and rig time, is estimated to be over one billion dollars [2]. it was reported based on a statistical survey over ten years period showed that the consequences of drilling losses in the mexico gulf were losing more than 12% of production time. similarly, studies have shown that losses can rise drilling costs by $70 to $100 for a foot on average [3]. the formations where losses occur are classified as follows:  losses in high permeability formation lost circulation into a matrix porous takes place during the drilling of high-permeability zones. majdi et al. explained that losses via pores begin slowly and steadily grow [4]. the filter cake on the wall of the wellbore activates progressively, which leads to a decline in the loss rate. losses finish when the drill bit passes through the high-permeability formation. to access the pore space, the pore size of the matrix should be greater than 3 times the diameter of the drilling mud's solid particles, as explained by g.beda et al. [5].  losses in vugular or cavernous zones vugular or cavernous formations are found in the rocks that have been dissolving throughout time. limestone, dolomite, and rock salt are examples of such rocks. when the drilling bit strikes these zones, the losses begin quickly. in such structures, total losses are possible [6].  losses happen in natural fracture the natural fractures, which occur prior drilling the well, may serve as conduits for drilling mud. natural fractures accounted for 76 percent of losses at one large operator [7]. the fracture should be broad adequate and http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:ali.hashim2008m@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2023.1.9 a. k. al-delfi et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 79 88 80 have sufficient permeability to let drilling mud to induce losses. when fractures are unlocked and linked, the ability of the fracture to soak up drilling mud might be nearly eternal, which result to occur severe or complete losses [8]. majdi et al. explained that losses into fractures begin quickly and gradually drop over time [4].  losses caused by induced fracture even if there are no substantial natural fractures, fractures are produced during drilling, and this leads to fluid losses. induced fracture occurs when the equivalent circulation density exceeds the fracture pressure of the formation. losses into induced fractures account for more than 90% of a large operator's losses costs [9].  losses in depleted reservoir producing zones in the same field may result in subnormal formation pressure as a result of formation fluid extraction. the formation pore pressure drops happen in the depleted reservoir. using the same mud density in these zones as in the remainder of the well will result in an increased overbalance. lost circulation into the depleted reservoir will increase as the overbalance rises [10]. the circulation losses in some wells, which are drilled in depleted reservoirs, are about thousands of barrels [11]. drilling fluid losses can be categorized based on the fluid volume lost in the drilled formation as follows:  seepage losses (when losses rate less than 1.6 m3/h)  partial losses (when losses rate between 1.6 16 m3/h)  severe losses (when losses more than 16 m3/h)  total losses (when no fluid returns to well surface) [12] to reduce mud losses and prevent related difficulties, many kinds of lost circulation materials (lcms) have been created and are being employed. each solution has advantages and disadvantages. as a result, no universal lost circulation material therapy has yet been developed which would be efficient in all zones and operational environments. the idea of using lcm has been around since the beginning of drilling operations. mt chapman's patent from 1890 described how to put a sealant substance into the drilling fluid. since that time, lcm has been routinely employed to prevent or reduce drilling fluid loss into the formation [13]. the categorization of lcms is a key aspect in making decisions about how to avoid and/or treat lost circulation situations. conventional lcms may be categorized as fibrous, flaky, granular, or a mix of these types [14]. howard et al. divided lcms into four categories regardless of physical properties: fibrous, granular, lamellated, and dehydratable [15]. robert white replaced the dehydratable class with a blend of lcm categories in the previous classification. because of the enormous number of existing accessible lcms and their various implementations, it is important to reclassify lcms into distinct groups [13]. a new classification was presented by alsaba et al. based on physical, chemical, and applications of lcm. granular, flaky, fibrous, lcm's combination, acid-soluble/water-soluble, and nanoparticles are the kinds of lcms [16]. savari et al assessed the effectiveness of lcm in sealing bigger gaps. an adapter with just a 31,700 micron hole was employed. when evaluated using a permeability plugging device (ppa), the mixture of high fluid loss squeeze (hfls) with various reticulated foam effectively sealed the aperture [17]. faleh al-mahdawi and karrar saad used the ltlp filter press to assess the effectiveness of silicon oxide nanoparticles. they discovered that increasing the concentration of nanoparticles causes the amount of filtrate to decrease [18]. amanullah and arfaj, used the waste of a deceased date tree as fibrous lcm. when compared to the commonly used commercial lcm product, the arc eco-fiber apparatus displayed improved sealing and plugging performance with little or no loss of total drilling mud [19]. noor amory and faleh almahdawi added the powder of pomegranate peel and grape seed to drilling mud and investigated their ability to promote the mud properties. their results indicated that the increased concentrations of the local materials powder reduced the fluid loss which it is good indicator to mitigate lost circulation [20]. alsaba et al. performed lab tests and concluded that lcm’s with particle size distribution (psd) implement preferable than particles of the same size. small particulates fill the gaps between bigger particles, resulting in a tighter plug [7]. savari et al. proved that, in most cases, combining lcms is more beneficial than using just one kind [21]. broussard et al. developed a unique engineered lcm chemically activated crosslinked pills (cacp). they used a mix of cross-linked polymer and fibrous cellulose to cure loss of circulation in deep water wells in the gulf of mexico. after the pill was set, circulation was entirely restored [22]. the main goal of this paper is to present the effect of polyacrylamide granular gel to reduce the lost circulation. polyacrylamide polymer gel (pam) systems have been frequently employed as plugging agents in heterogeneous reservoirs to regulate water output and increase sweep efficiency. polyacrylamide polymer gel systems are classified into three classes depending on their composition and application conditions, which are in-situ monomer gel, in-situ polymer gel, and preformed particle gel (ppg). 2experimental work 2.1. core preparation the utilised core in our experiments is a partially open fracture core. a partially open fracture mimics a natural fracture, which has an open fracture and ends in a porous formation. this core represents a natural core which is extracted from a well. a plug sample with a diameter of 1.5" and a length of 7 cm was extracted from a core by a. k. al-delfi et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 79 88 81 using a core driller. then this plug was cleaned by utilisation of a soxhlet extractor apparatus. toluene and alcohol were used as cleaning agents [23]. after that, an oven and a desiccator vessel were used to dry the plug. next, the plug sample is fully saturated with 1% nacl brine by using a vacuum desiccator. to generate a partially open fracture (pof), a plug was cut, by using a band saw, throughout the length of the cylinder core to a certain length, and the residual portion of the plug sample was left intact. the sliced part was divided into equal sized halves. by cutting through the designated region, one of the parts was extracted from the core. following the cutting, the surface of the plug sample was softly cleaned with a brine to prevent rock grains from reducing permeability. to preserve fracture geometry, two rectangular stainless steel plates of varying diameters were attached to the taller sides of the created fracture with epoxy. the width of the fracture is the plate thickness. the fracture's shorter edge was left exposed as a fluid intake. fig. 1 illustrates the manufacture of the pof model fracture construction. next, the plates were covered with the cut part of the plug. the fractured sample was reassembled and epoxy was used to stabilise it. the fluid entry dimension was a rectangle. fig. 2 shows the manufacture of the pof model reassembling the fractured plug, while fig. 3 shows the final front face of the plug sample. after that, the plug was coated with tin paper to prevent leakage of fluid from the body of the fractured samples, as shown in fig. 4 then the plug is placed inside a rubber sleeve, as illustrated in fig. 5 to ensure full control of fluid leakage before inserting it inside the core holder. fig. 1. manufacture of pof model fracture construction fig. 2. manufacture of pof model reassemble fractured plug fig. 3. final form of the plug sample fig. 4. plug sample coated with tin paper a. k. al-delfi et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 79 88 82 fig. 5. plug sample inside a rubber sleeve 2.2. experimental materials a. polyacrylamide (pam) a commercial polyacrylamide polymer gel was chosen as the specimen for tests. this product has low cost. acrylamide, or the mixture of acrylamide and acrylic acid, is the basis of polyacrylamide, which is water soluble. polyacrylamide (shortened as pam) is a polymer with the chemical formula (c3h5no). it is a white granular product and it has a linear-chain structure. the average particle size of the used polyacrylamide in our experiments is a millimetre. pam is extremely waterabsorbent and, when hydrated, forms a soft gel. fig. 6 illustrates a sample of polyacrylamide. fig. 6. sample of polyacrylamide b. sodium chloride (nacl) nacl is frequently called salt. it has the chemical formulation nacl and is an ionic substance. salt is a natural sodium chloride (nacl) and is used to formulate brines with specific gravity up to 1.20 and drilling muds. c. potassium chloride (kcl) kcl is a soluble salt which is an extremely effective shale stabiliser during drilling in hydrosensitive clay zones and shale formations. ion exchange provides inhibition; the potassium ion penetrates between the individual clay platelets in the shale to hold them together, preventing water from the drilling fluid from entering. kcl is used to make brines with a specific gravity of up to 1.15 and drilling muds. d. brine two types of brine are used in our experiments. the first one is a solution of 1% nacl brine, which is used for both brine flooding tests, and the other one is a solution of 2% kcl brine, which was utilised as a base fluid for all pam gel samples. e. pam gel solution the samples were prepared using the subsequent methods: the brine, a solution of 2% kcl, was first put into a beaker and placed on the magnetic stirrer. to avoid flocculation, the pam gel particulates were then gently introduced to the brine. after that, the mixture was left to blend until the pam gel particles had absorbed all of the brine. fig. 7 shows a pam gel solution immediately after mixing and after 1 hour of mixing. fig. 7. pam gel solution (a) immediately after mixing, (b) after 1 hour of mixing 2.3. core flooding system a core flooding system is used in our experiments and the schematic system is shown in fig. 8. to perform the tests, the brine and pam gel are placed in the accumulators before being pumped over the specimens in the core holder; this is accomplished via the test technique and the specific conditions. a hydraulic hand pump confines the core sample inward to the core holder with a rubber sleeve. a data logger device is used to collect and transmit electrical signals from transducers and other (a) (b) a. k. al-delfi et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 79 88 83 sensor devices to a computer. after that, ordel software is used to monitor the transducer (pressure sensor), which records both analogue and digital pressure data, to determine the response curve by measuring the pressure differential across a rock sample at various points during this process [24]. fig. 8. schematic of core flooding system 2.4. experimental procedure in our experiments, a core flooding system is used to evaluate the breakthrough pressure, which is the maximum pressure a material can withstand before cracking or forming internal channels, and plugging efficiency, which is calculated using the residual resistance factor (frr). frr represents the permeability reduction caused by using the pam gel. the plug sample was prepared as explained previously. firstly, the plug samples are extracted from a homogenous core, and then the samples are cleaned by using a soxhlet extractor apparatus. next, an oven and a desiccator vessel are used to dry the plug samples. the plugs are then weighted to calculate the dry weight of the samples. after that, the plugs are saturated with 1% brine, and then the plugs' wet weight is calculated in order to measure the porosity of the samples. finally, a partially open fracture is created and steel plates are put on to keep the opening of the fracture width. the plug was put into a core holder after being assembled once again as a whole cylinder. after preparing all the materials and equipment that are required to perform the test, the core flooding system is connected as illustrated in fig.8. the isco pump was filled with ro water and the hand pump was filled with hydraulic fluid. the brine and pam gel solution were poured into the upper parts of both accumulators. the plug sample was placed into the core holder. and then a confining pressure of 1000 psi was immobilized. finally, the test is performed and the data collected and analyzed. brine and pam gel were injected under pressure into the core holder, which contains a plug sample inside it, from the accumulators using a syringe pump. at a steady pumping rate of 1.0 ml/min, all experimental injection operations were completed. the flooding process includes three phases as below: a. first brine flooding 1% nacl brine was pumped into the fracture entrance at a flow rate of 1 ml/min until the pressure became stable. this stable pressure is used to calculate the permeability of the plug sample by using the darcy equation: k = q ϻ l a δp (1) where: k is the plug permeability (md). q is the flow rate (cm3/s). ϻ is the viscosity (cp). l is the plug sample length (cm). a is the cross section’s area of plug (cm2). δp is the differential pressure (stable pressure) (atm). b. pam gel placement the fully swollen pam gel was then pumped into the fracture using an accumulator from the opening inlet. the gel placement procedure was ended whenever the injection pressure stabilized or reached the desired value. the placement pressure, which was selected as the indication for pam gel injection completion, is defined as the highest injection pressure of gel [25]. 500, 1000, and 2000 psi were selected as amounts for placing pressures in partly open fracture models based on the injection pressure behavior of numerous gel therapy applications [26]. the fractured plug, with the pam gel sample inside it, remained in the core holder at room temperature for 1 hour to recrosslink the pam gel. a. k. al-delfi et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 79 88 84 c. second brine flooding any pam gel that remained in the connecting pipes was washed with water and air prior to the second brine flooding. the pam gel filter cake was extracted from the plug's front surface. the first accumulator was refilled with 1% nacl brine again prior to the next step starting. in the second brine flooding, 1% nacl brine was pumped with a flow rate of 1 ml/min till a stabilized pressure was reached. pressure measurements were taken during each phase in order to study how the pam gel spread and how the brine flowed. utilizing the pump's injection time, the injection volume was computed. after finishing the test and collecting the data, the residual resistance factor, which is referred to as the permeability reduction, and plugging efficiency are calculated based on the following equations: frr = kb ka (2) where: frr is the residual resistance factor. kb is the permeability of brine before gel treatment. ka is the permeability of brine after gel treatment. the relationship between residual resistance factor and plugging efficiency is: e = [1 − 1 frr ] ∗ 100 (3) where: e is the plugging efficiency %. 3discussion a core flooding test including first brine flooding, pam gel placement, and second brine flooding procedures was carried out in order to examine the overall behavior of pam gel treatment in a partially open fractured core (pof). the pof measured length is 3.5 cm, approximately half the length of the entire plug sample, which equals 7 cm. the stainless steel plate thickness regulated the width of the fracture, which was set at 0.3 cm. moreover, the height of the fracture is 2 cm. the fracture volume of the partially open fractured plug is calculated based on the volume of the rectangular equation. fv = wf ∗ hf ∗ lf (4) where: fv is the volume of the fracture (pof) (cm3). wf is the width of the fracture (cm). hf is the height of the fracture (cm). lf is the length of the fracture (cm). the plug sample with dimensions of 0.3 cm (wf), 2 cm (hf), and 3.5 cm (lf) has a fracture volume of 2.1 cm 3. after the plug sample is prepared as explained previously, it is put inside a rubber sleeve. a confining pressure of 1000 psi is applied to the rubber sleeve, which is inserted inside the core holder. 1% nacl brine is poured inside the first accumulator. after that, the isco pump is operated at a 1 ml/min flow rate. after getting a fixed pressure, the pump is powered off and all data is recorded. fig. 9 illustrates the first brine flooding injection pressure. it is obvious that the injection pressure rose to around 3.5 psi at the beginning of the 18th fv and dropped to approximately 1 psi at 50 fv. the two-phase flow in pof, which included both air, that was already present in the fracture, and brine, that was injected, was what created this pressure behavior. in the final phase of the first brine flooding, the pressure was fixed at around 1 psi. the partially open fracture had a remarkable permeability. as a result, the brine flow throughout the unbroken plug part behind the fracture section contributed the majority of the 1 psi, or pressure decrease, over the whole fractured core. eq. 1 is used to calculate the permeability prior to gel treatment and using a suitable convertor factor to be compatible with darcy's equation units. where: q = 1 ml/min, ϻ = 1 cp, l = 7 cm, a = 11.4 cm2, δp = 1 psi. the calculated permeability of the plug before gel treatment equals 150.38 md. fig. 9. injection pressure of the first brine flooding after finishing the first brine injection and getting a stable pressure, a 3% pam gel concentration is mixed with 2% kcl brine. then the gel suspension is poured into the second accumulator. after that, the isco pump is operated at a 1 ml/min flow rate. injection placement pressure for pam gel in all experiments was 1000 psi. as illustrated in fig. 10, the injection pressure gradually rose throughout the pam gel injection at first, notably between 0 and 3 fv. after that, the pressure rose more quickly, finally reaching 1000 psi. early on, particularly when pam gel did not arrive at the fracture end, it was pushing the brine within the fracture. when the gel had completely filled the pof area, the fracture tip prevented the injection from pushing the pam gel ahead. it is assumed that the pam gel was dehydrated due to the difference in pressure between the injection pressure and the matrix pressure [27]. the process of pam gel dehydration in the fracture is shown in fig. 11. depending on where the gel particle is, the direction of the pressure differential may change. because of the very small pressure difference between the a. k. al-delfi et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 79 88 85 fracture and the plug matrix, the pam gel suffered less from dehydration during the initial stages of injection. due to its comparatively lower elastic modulus, the less dehydrated gel was more flexible when pressure was applied to it [28]. consequently, the early gel injection pressure slope was low. throughout the whole injection operation, the pam gel was dehydrated progressively because of the pressure differential. because gel elastic modulus increased and it produced a stiffer resistance to water flow when it was applied, the slope of flooding pressure rose quickly from 3 to 6 pv. it is thought that three factors contributed to the increased resistance: (1) more pam gel being placed in the same volume, which could restrict the brine flow track; (2) a pam gel filter cake forming on the fracture's surfaces; and (3) a decrease in permeability brought on by gel invasion into the matrix's core. no pam gel particles were found in the effluent for the whole ppg injection, which lasted 6 fv. fig. 10. injection pressure of the pam gel flooding fig. 11. pam gel dehydrating under pressure difference after finishing the gel injection, the fractured plug remained in the core holder at room temperature for 1 hour for recrosslinking the pam gel. any pam gel that remained in the connecting pipes was washed with water and air prior to the second brine flooding. the pam gel filter cake was extracted from the plug's front surface. the first accumulator was refilled with 1% brine again prior to the next step starting. in the second brine flooding, 1% nacl brine was pumped with a flow rate of 1 ml/min till a stabilised pressure was reached. fig. 12 explains the second brine flooding pressure. the injection pressure enhanced slowly from the start of flooding to 20 fv. during this time, no effluent was seen, indicating that the pam gel in place completely prevented the flow of fluid through the fracture. after that, the pressure rose quickly and peaked at approximately 230 psi at 35 fv. this pressure is a breakthrough pressure. a considerable drop in pressure was then seen, going from 230 psi to 185 psi in 5 fv. the pressure drop showed that the packed gel was broken by the injected brine. when the injection pressure exceeded the breakthrough pressure, the layed pam gel particulates became capable of moving and moved aside by means of the pumped brine. the gel that had been put in moved, creating wormholes with extremely high permeabilities. the water injection pressure stabilised at roughly 193 psi from 42 to 50 fv. in comparison to the first brine flooding, the second brine flooding's steady pressure was significantly greater. the additional pressure drop created by the placement of gel, the cake of gel filter on the surface of the fracture, and the invasion of gel into the fracture surface area were the causes. fig. 12. injection pressure of the second brine flooding the plug sample permeability prior to gel treatment is calculated by utilizing the darcy eq. 1 by using the same variables used in the first brine flooding except using 193 psi as differential pressure. the calculated permeability equals 0.78 md. the residual resistance factor frr, which is referred to as the permeability reduction, of pam gel was computed based on the permeability of both two brine flooding in order to more accurately describe the plugging performance of the used gel. eq. 2 is used to compute the residual resistance factor. where: kb = 150.38 md and ka = 0.78 md. the calculated residual resistance factor, frr, equals 192.99. in other words, the permeability reduction after using pam gel as treatment for lost circulation is approximately 193 times. the plugging efficiency of gel treatment is calculated based on eq. 3. the calculated plugging efficiency e of the used pam gel is 99.48%. fig. 13 illustrates the plug sample before pam gel treatment, while fig. 14 shows the same plug sample after gel treatment. a. k. al-delfi et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 79 88 86 fig. 13. plug sample before pam gel treatment fig. 14. plug sample after pam gel treatment 4conclusions  the pam gel demonstrated encouraging results for fluid control losses while drilling.  overall, the pam gel can reduce the plug permeability, which means it is an effective material to mitigate the losses.  the permeability reduction caused by pam gel treatment reaches to two hundred.  the capacity of polyacrylamide granular gel to control lost circulation was investigated in great detail. according to this study, the polyacrylamide granular gel is a good option to be used as a lost circulation material (lcm) during drilling operations. nomenclature a plug cross section area, cm2 e plugging efficiency, % frr residual resistance factor, fraction fv fracture volume, cm3 hf fracture height, cm k absolute permeability, md ka absolute permeability before treatment, md kb absolute permeability after treatment, md l plug length, cm lf fracture length, cm q flow rate, ml/min wf fracture width, cm δp differential pressure, psi references [1] j. cook, f. growcock, q. guo, m. hodder, and e. van oort, “stabilizing the wellbore to prevent lost circulation,” oilf. rev., vol. 23, no. 4, pp. 26–35, 2011. [2] s. b al maskary, a. a. halim, and s. al menhali, “curing losses while drilling & cementing,” spe abu dhabi int. pet. exhib. conf., pp. 2492–2497, 2014, https://doi.org/10.2118/171910-ms. [3] m. i. magzoub, s. salehi, i. a. hussein, and m. s. nasser, “loss circulation in drilling and well construction: the significance of applications of crosslinked polymers in wellbore strengthening: a review,” j. pet. sci. eng., vol. 185, 2020, https://doi.org/10.1016/j.petrol.2019.106653. [4] r. majidl, s. z. miska, m. yu, l. g. thompson, and j. zhang, “quantitative analysis of mud losses in naturally fractured reservoirs: the effect of rheology,” spe drill. complet., vol. 25, no. 4, pp. 509–517, 2010, https://doi.org/10.2118/114130-pa. [5] g. beda and c. carugo, “use of mud microloss analysis while drilling to improve the formation evaluation in fractured reservoir,” spe annu. tech. conf. exhib., pp. 3687–3699, 2001, https://doi.org/10.2118/71737-ms. [6] a. lavrov, lost circulation mechanisms and solutions. 2016. [7] m. alsaba, r. nygaard, a. saasen, and o. m. nes, “lost circulation materials capability of sealing wide fractures,” spe deep. drill. complet. conf., pp. 270– 281, 2014, https://doi.org/10.2118/170285-ms. [8] a. kumar, s. savari, d. whitfill, and d. jamison, “application of fiber laden pill for controlling lost circulation in natural fractures,” aade natl. tech. conf. exhib., 2011. [9] f. e. dupriest, “fracture closure stress (fcs) and lost returns practices,” spe/iadc drill. conf., pp. 173–183, 2005, https://doi.org/10.2118/92192-ms. [10] j. gradishar, g. ugueto, and e. van oort, “setting free the bear: the challenges and lessons of the ursa a-10 deepwater extended-reach well,” spe drill. complet., vol. 29, no. 2, pp. 182–193, 2014, https://doi.org/10.2118/163525-pa. [11] s. m. willson et al., “wellbore stability challenges in the deep water, gulf of mexico: case history examples from the pompano field,” spe annu. tech. conf. exhib., pp. 1833–1842, 2003, https://doi.org/10.2118/84266-ms. [12] d. (chevron) ferron and b. (chevron) smiley, lost circulation guide, , drilling specialties company. 2014. [13] r. j. white, “lost-circulation materials and their evaluation,” drill. prod. pract., 1956. [14] b. e. canson, “lost circulation treatments for naturally fractured, vugular, or cavernous formations,” spe/iadc drill. conf., pp. 155–166, 1985, https://doi.org/10.2118/13440-ms. https://www.researchgate.net/profile/frederick-growcock/publication/290592459_stabilizing_the_wellbore_to_prevent_lost_circulation/links/590e1b0f458515978185c5f3/stabilizing-the-wellbore-to-prevent-lost-circulation.pdf https://www.researchgate.net/profile/frederick-growcock/publication/290592459_stabilizing_the_wellbore_to_prevent_lost_circulation/links/590e1b0f458515978185c5f3/stabilizing-the-wellbore-to-prevent-lost-circulation.pdf https://www.researchgate.net/profile/frederick-growcock/publication/290592459_stabilizing_the_wellbore_to_prevent_lost_circulation/links/590e1b0f458515978185c5f3/stabilizing-the-wellbore-to-prevent-lost-circulation.pdf https://www.researchgate.net/profile/frederick-growcock/publication/290592459_stabilizing_the_wellbore_to_prevent_lost_circulation/links/590e1b0f458515978185c5f3/stabilizing-the-wellbore-to-prevent-lost-circulation.pdf https://doi.org/10.2118/171910-ms https://doi.org/10.1016/j.petrol.2019.106653 https://doi.org/10.2118/114130-pa https://doi.org/10.2118/71737-ms https://books.google.iq/books?hl=en&lr=&id=z0_pcaaaqbaj&oi=fnd&pg=pp1&dq=%5b1%5d%09a.+lavrov,+lost+circulation+mechanisms+and+solutions.+2016.&ots=dnbujbogl6&sig=3vo5dqp1gklzlitsftagqgpcwuw&redir_esc=y#v=onepage&q=%5b1%5d%09a.%20lavrov%2c%20lost%20circulation%20mechanisms%20and%20solutions.%202016.&f=false https://books.google.iq/books?hl=en&lr=&id=z0_pcaaaqbaj&oi=fnd&pg=pp1&dq=%5b1%5d%09a.+lavrov,+lost+circulation+mechanisms+and+solutions.+2016.&ots=dnbujbogl6&sig=3vo5dqp1gklzlitsftagqgpcwuw&redir_esc=y#v=onepage&q=%5b1%5d%09a.%20lavrov%2c%20lost%20circulation%20mechanisms%20and%20solutions.%202016.&f=false https://doi.org/10.2118/170285-ms https://doi.org/10.2118/92192-ms https://doi.org/10.2118/163525-pa https://doi.org/10.2118/84266-ms https://doi.org/10.2118/13440-ms a. k. al-delfi et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 79 88 87 [15] g. c. howard and p. p. scott, “an analysis and the control of lost circulation,” j. pet. technol., vol. 192, no. 06, pp. 171–182, 1951, https://doi.org/10.2118/951171-g. [16] m. t. alsaba, r. nygaard, and g. hareland, “review of lost circulation materials and treatments with an updated classification lost circulation view project drilling optimization view project,” am. assoc. drill. eng., 2014. [17] s. savari, j. butcher, and m. al-hulail, “managing lost circulation in highly fractured, vugular formations: engineered usage of high fluid loss squeeze and reticulated foam lost circulation materials,” spe/iadc drill. conf., 2020, https://doi.org/10.2118/199635-ms. [18] al-mahdawi f and saad k., “enhancement of drilling fluid properties using nanoparticles,” iraqi j. chem. pet. eng., vol. 19, no. 2, pp. 21–26, 2018. [19] m. amanullah and m. k. arfaj, “date palm treebased fibrous lcm ‘arc eco-fiber’ -a better alternative to equivalent imported products,” spe kingdom saudi arab. annu. tech. symp. exhib., 2018, https://doi.org/10.2118/192160-ms. [20] n. s. amory and f. h. m. almahdawi, “experimental investigation of pomegranate peel and grape seed powder additives on the rheological and filtration properties of un-weighted wbm,” iraqi j. chem. pet. eng., vol. 21, no. 4, pp. 33–40, 2020, https://doi.org/10.31699/ijcpe.2020.4.4. [21] s. savari, d. l. whitfill, d. e. jamison, and a. kumar, “a method to evaluate lost-circulation materials investigation of effective wellborestrengthening applications,” spe drill. complet., vol. 29, no. 3, pp. 329–333, 2014, https://doi.org/10.2118/167977-pa. [22] d. e. caughron et al., “unique crosslinking pill in tandem with fracture prediction model cures circulation losses in deepwater gulf of mexico,” iadc/spe drill. conf., pp. 483–490, 2002, https://doi.org/10.2118/74518-ms. [23] u. alameedy, a. a. alhaleem, a. isah, a. al-yaseri, m. mahmoud, and i. s. salih, “effect of acid treatment on the geomechanical properties of rocks: an experimental investigation in ahdeb oil field,” j. pet. explor. prod. technol. accept. publ., no. 0123456789, 2022, https://doi.org/10.1007/s13202-022-01533-x. [24] u. alameedy and a. al-haleem, “the impact of matrix acidizing on the petrophysical properties of the mishrif formation: experimental investigation,” iraqi geol. j., vol. 55, no. 1e, pp. 41–53, 2022, https://doi.org/10.46717/igj.55.1e.4ms-2022-05-20. [25] a. k. alhuraishawy, a. imqam, m. wei, and b. bai, “experimental study of combining low salinity water flooding and preformed particle gel to enhance oil recovery for fractured carbonate reservoirs,” fuel, 2018, https://doi.org/10.1016/j.fuel.2017.10.060. [26] g. p. hild and r. k. wackowski, “reservoir polymer gel treatments to improve miscible co2 flood,” spe reserv. eval. eng., vol. 2, no. 2, pp. 196–204, 1999, https://doi.org/10.2118/56008-pa. [27] r. s. seright, “polymer gel dehydration during extrusion through fractures,” spe prod. facil., vol. 14, no. 2, pp. 110–116, 1999, https://doi.org/10.2118/56126-pa. [28] p. j. flory and j. rehner, “statistical mechanics of cross-linked polymer networks i. rubberlike elasticity,” the journal of chemical physics, vol. 11, no. 11. pp. 512–520, 1943, https://doi.org/10.1063/1.1723791. https://doi.org/10.2118/951171-g https://tarjomefa.com/wp-content/uploads/2019/01/f1180-tarjomefa-english.pdf https://tarjomefa.com/wp-content/uploads/2019/01/f1180-tarjomefa-english.pdf https://tarjomefa.com/wp-content/uploads/2019/01/f1180-tarjomefa-english.pdf https://tarjomefa.com/wp-content/uploads/2019/01/f1180-tarjomefa-english.pdf https://tarjomefa.com/wp-content/uploads/2019/01/f1180-tarjomefa-english.pdf https://doi.org/10.2118/199635-ms https://www.iasj.net/iasj/download/597ec46d4786816a https://www.iasj.net/iasj/download/597ec46d4786816a https://www.iasj.net/iasj/download/597ec46d4786816a https://doi.org/10.2118/192160-ms https://doi.org/10.31699/ijcpe.2020.4.4 https://doi.org/10.2118/167977-pa https://doi.org/10.2118/74518-ms https://doi.org/10.46717/igj.55.1e.4ms-2022-05-20 https://doi.org/10.1016/j.fuel.2017.10.060 https://doi.org/10.2118/56008-pa https://doi.org/10.2118/56126-pa https://doi.org/10.1063/1.1723791 a. k. al-delfi et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 79 88 88 دراسة تجريبية لتقصي تأثير جل بولي أكريالميد لتقليل فقدان دورة سائل الحفر 3، ويوسف الطاهر بغادي 2 ياسر مختار، 1 فالح حسن محمد المهداوي ،* ،1علي كريم الدلفي قسم هندسة النفط، كلية الهندسة، جامعة بغداد، العراق 1 النفط، بكين، الصين جامعة 2 جامعة العلوم والتكنولوجيا، السودان 3 الخالصة أ العديد إحدى المشكالت الصعبة التي تتم مواجهتها أثناء عمليات الحفر هي فقدان دورة سائل الحفر. قد تنش نواع أمن المشكالت بسبب هذه المشكلة، مثل المزيد من الوقت الضائع ونفقات الحفر المرتفعة. تم تطوير عدة رتبطة تجنب المشكالت المن خسائر الطين و للحد ميتم استخدامها المواد المانعة لفقدان السوائل و مختلفة من بها. كل حل له فوائد و عيوب. تقليل ( لpam، تم إجراء اختبار الغمر األساسي لدراسة فعالية هالم حبيبات بولي أكريالميد )في هذه الدراسة م باس لمعروفا ، وصائص الكسر هو الكسور ذات الرؤوسالمفقودة. أحد األنواع الشائعة لخ دورة سائل الحفر القليل من االهتمام في pofsفي pam، تلقى العالج الهالمي (. ومع ذلكpofالكسر المفتوح جزئًيا ) سلسلة أسطواني. يتم تنفيذ لباب صخري . تم بناء نماذج من الكسور المفتوحة جزئًيا باستخدام ةث السابقو البح من pamشكل عام ، يمكن أن يقلل هالم . بpofللحصول على نموذج اللباب الصخري من العمليات على ريالميد بولي أكالمفقود. تشير النتائج إلى أن هالم ال للحد من سائل الحفر، مما يجعلها مادة مفيدة نفاذية السدادة مرة. 193الحبيبي يمكن أن يقلل من النفاذية حتى .pam ،بولي أكريالميد ،lcm ،المفقودةدورة سائل الحفر الكلمات الدالة: available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol. 24 no.2 (june 2023) 89 – 95 eissn: 2618-0707, pissn: 1997-4884 *corresponding author: name: alyaa m. ali, email: alyaa.mahmood.eng@gmail.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. determination of reservoir hydraulic flow units and permeability estimation using flow zone indicator method alyaa m. ali a, b, * and ayad a. alhaleem a a petroleum engineering department, college of engineering, university of baghdad, iraq b oil and gas engineering department, university of technology, iraq abstract reservoir characterization plays a crucial role in comprehending the distribution of formation properties and fluids within heterogeneous reservoirs. this knowledge is instrumental in constructing an accurate three-dimensional model of the reservoir, facilitating predictions regarding porosity, permeability, and fluid flow distribution. among the various methods employed for reservoir characterization, the hydraulic flow unit stands out as a widely adopted approach. by effectively subdividing the reservoir into distinct zones, each characterized by unique petrophysical and geological properties, hydraulic flow units enable comprehensive reservoir analysis. the concept of the flow unit is closely tied to the flow zone indicator, a critical parameter that defines the porosity-permeability relationships of each hydraulic flow unit. additionally, the flow zone indicator method proves valuable in estimating permeability accurately. in this study, we demonstrate the application of the flow zone indicator method to determine hydraulic flow units within the khasib formation. by analyzing core data and calculating the rock quality index (rqi) and flow zone indicator (∅z), we differentiate the formation into four hydraulic flow units based on fzi values. specifically, hfu 1 represents a rock of poor quality, corresponding to compact and chalky limestone. hfu 2 represents intermediate quality, corresponding to argillaceous limestone, while hfu 3 represents good quality, corresponding to porous limestone. lastly, hfu 4 signifies an excellent reservoir rock quality characterized by vuggy limestone. by establishing a permeability equation that correlates with effective porosity for each rock type, we successfully estimate permeability. comparing these estimated permeability values with core permeability reveals a strong agreement with a high correlation coefficient of 0.96%. consequently, the flow zone indicator method effectively classifies the khasib formation into four distinct hydraulic flow units and provides an accurate and reliable means of determining permeability in the reservoir. the resulting permeability equations can be applied to wells and depth intervals lacking core measurements, further emphasizing the practical utility of the fzi method. keywords: reservoir characterization, hydraulic flow unit, flow zone indicator, permeability estimation, khasib formation. received on 03/07/2022, received in revised form on 03/08/2022, accepted on 04/08/2022, published on 30/06/2023 https://doi.org/10.31699/ijcpe.2023.2.10 1introduction reservoir characterization is a very difficult assignment due to the fact that there is always some degree of heterogeneity in the reservoir properties, making them change in spatial at all levels from pore to reservoir level, particularly in carbonate formation, which shows a high level of properties variation due to the environment in which it is deposited and the processes of digenetic exposure [1]. effective reservoir characterization and utilization require a clear distinction in pore geometry among different lithofacies. these distinctions have resulted in a new subdivision described as flow units [2]. the idea of a flow unit was presented by hearn et al. [3] in order to systematically characterize how different types of rock are distributed throughout the formation and how they effectively control the flow of fluids. a flow unit was defined as a portion of the subsurface formation that shows analogous petrophysical and bedding properties in both vertical and lateral directions. furthermore, ebanks [4] described the flow unit as a portion of the entire reservoir rock where the flow of fluid is affected by the geological and petrophysical properties that appear to be stable and certainly dissimilar to the properties of other reservoir rocks. rock typing can be defined as the process of associating a formation rock's characteristics with its geological facies. the geology and reservoir characteristics of the ideal rock type are the same. geology, reservoir (static characteristics), and petrophysics are the three types of this procedure [5]. the main goal of rock typing is to describe the relation between petrophysics and geology. rock type can be thought of as a petrophysically and geologically homogeneous set of rocks with distinct porosity, water saturation, and permeability relationship [6]. when using the hydraulic unit approach, the rock types can be described as parts of the rock that have specific relation between permeability and porosity, relative permeability curves, and capillary pressure profiles. it's useful for characterization and simulation studies of reservoirs. correct rock typing leads to accurate http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:alyaa.mahmood.eng@gmail.com http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2023.2.10 a. m. ali and a. a. alhaleem / iraqi journal of chemical and petroleum engineering 24,2 (2023) 89 95 90 initial water saturation profiles and, as a result, credible reservoir modeling studies as well as a reliable calculation of permeability in un-cored wells. [7, 8]. characterizing the reservoir and identifying the type of rock are important tools for forecasting reservoir performance and comprehending reservoir design [9]. integrated rock characterization can be carried out in detail using the flow zone indicator method to describe the formation in terms of hydraulic flow unit; winland correlation to classify the pore size; lucia classification to classify the types of rock depending on fabric rock number, and clustering analysis to recognize rock type with the data of well logs [10]. the core data for three wells (x-1, x-2, and x-3) provided information about porosity and permeability measurements [11]. these data were used to characterize the reservoir into discrete hydraulic flow units by using the flow zone indicator method. these flow units describe the formation and subdivide it into different rock types characterized by different porosity-permeability relationships. after that, for permeability estimation, we use the porosity-permeability equations that have been created for each hydraulic flow unit. 2area of case study the target field is x oilfield, which is located in southeastern iraq in the missan governorate, about 10 km to the southwest of amara city fig. 1. the field was discovered in 1957 and put into production in 2000. the field is operated by missan oil company and currently has 18 drilled wells. the field's structure is a single semisymmetrical anticline with a northwest to south east axis. its length and width are approximately 18 km and 4.5 km, respectively [11]. the field is produced through three main reservoirs: mishrif, khasaib, and nahr-umr formations. the reservoir under study is the khasib carbonate formation, which is considered one of the significant petroleum reserves in the south of iraq. the khasib formation in this field is roughly between 75 and 80 meters thick. fig. 1. the location map of iraq and the red circle referred to the location of the x oilfield [12] 3geological setting of khasib formation petroleum accumulation primarily occurs in the southern and central regions of iraq and is confined to a mesopotamian basin anticline subsurface structure [13]. the zubair (south), euphrates (west), and tigris (east) subzones make up the mesopotamian basin. tigris subzone contains the x oilfield. the mesopotamian basin's turonian-campanian sedimentary cycle is fully represented by the formations khasib, tanuma, and sa'di [14]. in some oilfields, these porous and fractured carbonate layers serve as particularly productive formations, alternating with numerous shale/marl units in this carbonate sequence. the entire sequence's microfacies and lithostratigraphic investigations, disregarding the diversity of the fauna and the sorts of fossils, show nearly identical depositional settings [15]. in a number of oil fields, including those in tikrit, balad, samarra, east baghdad, ahdab, amarah, halfaya, jerishan, and majnoon, the khasib formation is considered one of the main oil-potential rocks [16]. nearly 14% of iraq's cretaceous hydrocarbon reserves and roughly 10% of the country's total proven oil reserves are included in this formation [17]. khasib formation lies below the tanuma formation and above the kifl formation in the central and western regions of iraq, while the mishrif formation is in the southern region's equivalent of the kifl formation fig. 2. the majority of the khasib formation is made up of late cretaceous limestone and marlstones that are heavily bioturbated and contain planktonic foraminifera and calcispheres [18]. fig. 2. south iraq stratigraphic column [9] a. m. ali and a. a. alhaleem / iraqi journal of chemical and petroleum engineering 24,2 (2023) 89 95 91 4methodology hydraulic flow unit theory the hydraulic flow unit (hfu) method was established by amaefule et al. [19] and it is based on the concept of the bundle of capillary tubes presented by kozeny [20] and carmen [21]. amaefule et al. [19] use the hydraulic unit (hu) to recognize the various rock types in the reservoir as a result of permeability changing even in the rock type that is well defined. hfu is used to represent that part of the reservoir when the petrophysical and geological features within it differ from those of other rock parts [7]. the kozeny-carmen equation in its generalized form is represented by the eq. 1: 𝐾 = ∅𝑒3 (1−∅𝑒)2 ( 1 𝐹𝑠 𝜏2𝑆𝑔𝑣2 ) (1) here, k represents the permeability in μm2, ∅e is effective porosity in fraction units, sgv2 represents specific surface area per unit grain in μm-1, fs is shape factor, and 𝜏 is the tortuosity, both fs and 𝜏 in the dimensionless unit, amaefule et al. [19] re-arranged eq. 1 and separated the parameters that are constant for a hydraulic unit to reach the eq. 2: 0.0314√ 𝐾 ∅𝑒 = ∅𝑒 (1−∅𝑒) ( 1 √𝐹𝑠 𝜏 𝑆𝑔𝑣 ) (2) the equation is presented in field units with permeability in md unit. the above equation can be expressed by introducing new parameters defined in eqs. 3, 4, and 5: rqi (μm) = 0.0314 √ k ∅e (3) ∅z = ∅e 1−∅e (4) fzi = 1 √fs τ sgv = rqi ∅z (5) rqi is the reservoir quality index, ∅𝑧 is the ratio of pore volume-to-grain volume, and fzi is the flow zone indicator, which is a unique parameter that combines texture and mineralogy in the division of distinct hydraulic flow units. each flow unit has a different fzi value that describes the distribution of pore space geometry by correlating the rqi and ∅𝑧. by taking the logarithm for each side of the eq. 5, log 𝑅𝑄𝐼 = log 𝐹𝑍𝐼 + log ∅𝑧 (6) the log-log plot of rqi vs. ∅𝑧, will generate a straight line with a slop value that is equal to one. on the other hand, the data with different fzi values will be placed on a distinct parallel liner site [19]. the fzi mean value can be calculated from the interception of each straight line with ∅𝑧 =1. all points located on the same line are distinguished to have similar pore throat structures, forming a hydraulic unit. the permeability in a cored well can be calculated for each hydraulic flow unit by using the mean values for fzi and the effective porosity. 𝐾 = 1014 × 𝐹𝑍𝐼𝑚𝑒𝑎𝑛 2 × ∅𝑒2 (1−∅𝑒)2 (7) the principle of hydraulic flow unit can be generalized to un-cored wells using artificial intelligence (ai), especially artificial neural networks. a permeability predictive model can be developed using artificial neural networks (ann) to predict the hydraulic flow unit and estimate the permeability in wells with unavailable core measurements. this is done by building a model that correlates the available core and well-log data [22]. 5results and discussion the hydraulic flow unit was identified by applying the flow zone indicator method to core measurements of three wells (x1, x2, and x3). this method offers a fairly adequate classification for the data under consideration. the results clarify that the examined reservoir consists of four hydraulic flow units. each hfu has consistent ranges of fzi and represents a specific rock type with different porosity and permeability properties fig. 3. the highest fzi values for the best quality rocks are represented by (fzi 3) while the lowest fzi values for the worst quality rocks are (fzi 0). fig. 3. reservoir quality index (rqi) versus the normalized porosity for three wells a semi-logarithmic plot of core-derived permeability with effective porosity is applied to demonstrate the relation between these two important petrophysical properties for each distinct hydraulic flow unit. based on the values of fzi, which represent different hfus, four groups were recognized in the permeability–porosity plot fig. 4. one correlation equation is determined for each hfu that correlates the core permeability and core porosity with the correlation coefficient values. it is evident that the accuracy of the hfu technique in correlating permeability with porosity is demonstrated by the r2 of each correlation equation as represented in table 1. a. m. ali and a. a. alhaleem / iraqi journal of chemical and petroleum engineering 24,2 (2023) 89 95 92 fig. 4. core permeability versus core effective porosity for three wells table 1. characterizing reservoir rock using the hfu method hfu k∅ relationships r² description hfu 1 hfu 2 hfu 3 hfu 4 y = 220.4x3.539 y= 11252x4.573 y=29011x4.0533 y=77153x3.8513 0.71 0.86 0.78 0.96 poor rock properties moderate rock properties good rock properties best rock properties for the hfu 1, the permeability values ranged from (0.01 to 7). for the hfu 2, the permeability values ranged from (0.32 to 60). for the hfu 3, the permeability values ranged from (43 to 104). for the hfu 4, the permeability values ranged from (2.9 to 773). the porosity of the formation was ranging from 0.06 to 0.28. each hfu can be described as a different rock type. relating the hfus with their signified petrophysical properties to the geological description from the final geological reports will result in the final characterization of the rock types that make up the khasib formation as represented in table 2. table 2. rock types of khasib formation hfu final geological reports description rock type hfu 1 hfu 2 hfu 3 hfu 4 compact limestone and chalky argillaceous limestone porous limestone vuggy limestone rt1 rt2 rt3 rt4 in order to verify the reliability of the permeability value from the above equations, we compared the resulted permeability with the core permeability as shown in fig. 5. the correlation coefficient was 0.96, which describes how the calculated permeability is close to the core permeability, and this high value of the correlation coefficient gives an idea about how accurate it is to estimate permeability using the hydraulic flow units from fzi methods. the results were plotted and described for one well using techlog software as shown in fig. 6. the estimated permeability from the fzi method and the core permeability are represented in the first column, the corresponding fzi groups in the second column, and hfus in the third column are described by a different color for each zone. khasib formation was characterized by five electrofacies using cluster analysis. these facies consist of vuggy, porous, argillaceous, chalky, and compacted marl limestone [23]. these electrofacies from cluster analysis can be compared to the rock types characterized using the fzi method, which shows the similarity between the results of the two methods in characterizing khasib formation. fig. 5. comparison between estimated permeability and core permeability fig. 6. estimated permeability versus core permeability with the values of fzi with hfu for well x2 6conclusions  the flow zone indicator method is such an effective tool for characterizing the reservoir into distinct hydraulic flow units that reflect different types of rock.  four hydraulic flow units are characterized in the khasib reservoir (hfu 1 represents poor reservoir rock quality, hfu 2 represents intermediate reservoir rock quality, hfu 3 represents good reservoir rock a. m. ali and a. a. alhaleem / iraqi journal of chemical and petroleum engineering 24,2 (2023) 89 95 93 quality, and hfu4 represents excellent reservoir rock quality).  four rock types were identified by the fzi method. rt1 represents the poor rock with bad porositypermeability values, which correspond to the compacted limestone and chalky limestone. rt2 with moderate properties corresponds to argillaceous limestone, rt3 corresponds to porous limestone with good porosity-permeability values, and rt4 with the best petrophysical properties corresponds to the vuggy limestone rock.  the permeability equations resulting from using the fzi method show a good correlation coefficient r2 for each hfu, and when comparing the permeability that was calculated from the hfu with core permeability, the correlation coefficient shows high agreement. the resultant empirical equations can be generalized and used for estimating permeability in wells or intervals that are with unavailable core data based on the value of porosity from the log. acknowledgments the authors would like to express sincere thanks and gratitude to missan oil company (m.o.c) for providing the data used. nomenclature ai artificial intelligence ann artificial neural network fzi flow zone indicator hfu hydraulic flow unit hfus hydraulic flow units r2 correlation coefficient rqi reservoir quality index rt rock type ∅𝑧 normalized porosity references [1] v. singh, "key factors affecting 3d reservoir interpretation and modelling outcomes: industry perspectives", british journal of applied science and technology, vol. 3, no. 3, pp. 376-405, 2013. https://doi.org/10.9734/bjast/2014/3089 [2] e. enaworu, l. o. ajana and o. d. orodu, "permeability prediction in wells using flow zone indicator (fzi)", petroleum and coal, vol. 58, no. 6, pp. 640-645, 2016. [3] c. hearn, w. ebanks, r. tye and v. ranganathan, "geological factors influencing reservoir performance of the hartzog draw field, wyoming", journal of petroleum technology, vol. 36, no. 08, pp. 1335-1344, 1984. https://doi.org/10.2118/12016-pa [4] o. d. orodu, z. tang, and q. fei, “hydraulic (flow) unit determination and permeability prediction: a case study of block shen-95, liaohe oilfield, northeast china,” journal of applied sciences, vol. 9, no. 10, pp. 1801–1816, 2009.: https://doi.org/10.3923/jas.2009.1801.1816 [5] v. tavakoli, "geological core analysisapplication to reservoir characterization", gewerbestrasse 11, 6330 cham, switzerland: springer briefs in petroleum geoscience & engineering, 2018. https://doi.org/10.1007/978-3-319-78027 -6 [6] m. rebelle and b. lalanne, "rock-typing in carbonates: a critical review of clustering methods", 2014. https://doi.org/10.2118/171759-ms [7] d. davies and r. vessell, "identification and distribution of hydraulic flow units in a heterogeneous carbonate reservoir: north robertson unit, west texas", all days, 1996. https://doi.org/10.2118/35183-ms [8] s. shenawi, j. white, e. elrafie and k. el-kilany, "permeability and water saturation distribution by lithologic facies and hydraulic units: a reservoir simulation case study", all days, 2007. https://doi.org/10.2118/105273-ms [9] a. m. ali and a. a. alrazzaq, “applying facies characterization to build 3d rock-type model for khasib formation, amara oil field,” iraqi journal of oil and gas research (ijogr), vol. 3, no. 1, pp. 94– 105, 2023. https://doi.org/10.55699/ijogr.2023.0301.1040 [10] s. al-jawad, m. ahmed and a. saleh, "integrated reservoir characterization and quality analysis of the carbonate rock types, case study, southern iraq", journal of petroleum exploration and production technology, vol. 10, no. 8, pp. 31573177, 2020. https://doi.org/10.1007/s13202-02000982-6 [11] inoc iraq," special core analysis reports for wells am-1, am-2, and am-3", missan oil company, iraq, 1985. [12] a. a. m. aqrawi, j. c.goff, a. d. horbury and f. n. sadooni, "the petroleum geology of iraq", 1st edition. scientific press, p. 424, 2010. [13] t. al-ameri and r. al-obaydi, "cretaceous petroleum system of the khasib and tannuma oil reservoir, east baghdad oil field, iraq", arabian journal of geosciences, vol. 4, no. 5-6, pp. 915-932, 2010. https://doi.org/10.1007/s12517-009-0115-4 [14] s. jassim, j. goff, "geology of iraq", 1st edition, dolin, prague, and moravian museum, brno, p. 353, 2006. [15] a. a. m. aqrawi, "carbonate-siliciclastic sediments of the upper cretaceous (khasib, tanuma and sa'di formations) of the mesopotamian basin", marine and petroleum geology, vol. 13, no. 7, pp. 781-790, 1996. https://doi.org/10.1016/0264-8172(96)00022-0 [16] b. al-qayim, "sequence stratigraphy and reservoir characteristics of the turonian-coniacian the khasib formation in central iraq ", journal of petroleum geology, vol. 33, no. 4, pp. 387-403, 2010. https://doi.org/10.1111/j.1747-5457.2010.00486.x [17] j. a. al-sakini, "summary of petroleum geology of iraq and middle east", northern oil company press, kirkuk, pp. 186 (in arabic), 1992. https://doi.org/10.9734/bjast/2014/3089 https://doi.org/10.2118/12016-pa https://doi.org/10.3923/jas.2009.1801.1816 https://doi.org/10.1007/978-3-319-78027%20-6 https://doi.org/10.2118/171759-ms https://doi.org/10.2118/35183-ms https://doi.org/10.2118/105273-ms https://doi.org/10.55699/ijogr.2023.0301.1040 https://doi.org/10.1007/s13202-020-00982-6 https://doi.org/10.1007/s13202-020-00982-6 https://books.google.iq/books?hl=en&lr=&id=llh8aygmjfwc&oi=fnd&pg=pa15&dq=geology+of+iraq&ots=rz-i5yjkyg&sig=_ucoaqr3xhfl8garna8getraewg&redir_esc=y#v=onepage&q=geology%20of%20iraq&f=false https://books.google.iq/books?hl=en&lr=&id=llh8aygmjfwc&oi=fnd&pg=pa15&dq=geology+of+iraq&ots=rz-i5yjkyg&sig=_ucoaqr3xhfl8garna8getraewg&redir_esc=y#v=onepage&q=geology%20of%20iraq&f=false https://books.google.iq/books?hl=en&lr=&id=llh8aygmjfwc&oi=fnd&pg=pa15&dq=geology+of+iraq&ots=rz-i5yjkyg&sig=_ucoaqr3xhfl8garna8getraewg&redir_esc=y#v=onepage&q=geology%20of%20iraq&f=false https://doi.org/10.1016/0264-8172(96)00022-0 https://doi.org/10.1111/j.1747-5457.2010.00486.x a. m. ali and a. a. alhaleem / iraqi journal of chemical and petroleum engineering 24,2 (2023) 89 95 94 [18] f. sadooni, "stratigraphy, depositional setting and reservoir characteristics of turonian campanian carbonates in central iraq", journal of petroleum geology, vol. 27, no. 4, pp. 357-371, 2004. https://doi.org/10.1111/j.1747-5457.2004.tb00063.x [19] j. amaefule, m. altunbay, d. tiab, d. kersey and d. keelan, "enhanced reservoir description: using core and log data to identify hydraulic (flow) units and predict permeability in uncored intervals/wells", all days, 1993. https://doi.org/10.2118/26436-ms [20] a. sokhal, z. benaissa, s. a. ouadfeul, and a. boudella, “dynamic rock type characterization using artificial neural networks in hamra quartzites reservoir: a multidisciplinary approach,” engineering, technology &amp;amp; applied science research, vol. 9, no. 4, pp. 4397–4404, 2019. https://doi.org/10.48084/etasr.2861 [21] p. c. carman, “fluid flow through granular beds,” chemical engineering research and design, vol. 75, 1997. https://doi.org/10.1016/s0263-8762(97)800032 [22] d. abdulhadi alobaidi, "permeability prediction in one of iraqi carbonate reservoir using hydraulic flow units and neural networks", iraqi journal of chemical and petroleum engineering, vol. 17, no. 1, pp. 1-11, 2016. [23] a. mohammed, m. dhaidan, s. al-hazaa, s. farouk and k. al-kahtany, "reservoir characterization of the upper turonian – lower coniacian khasib formation, south iraq: implications from electrofacies analysis and a sequence stratigraphic framework", journal of african earth sciences, vol. 186, pp. 104431, 2022. https://doi.org/10.1016/j.jafrearsci.2021.104431 https://doi.org/10.1111/j.1747-5457.2004.tb00063.x https://doi.org/10.2118/26436-ms https://doi.org/10.48084/etasr.2861 https://doi.org/10.1016/s0263-8762(97)80003-2 https://doi.org/10.1016/s0263-8762(97)80003-2 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/85 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/85 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/85 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/85 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/85 https://doi.org/10.1016/j.jafrearsci.2021.104431 a. m. ali and a. a. alhaleem / iraqi journal of chemical and petroleum engineering 24,2 (2023) 89 95 95 نطقة ممؤشر تحديد وحدات التدفق الهيدروليكي للمكمن وحساب النفادية باستخدام طريقة التدفق 1 و اياد عبد الحليم عبد الرزاق ، *2، 1علياء محمود علي العراق، جامعة بغدادقسم هندسة النفط، كلية الهندسة، 1 العراق لوجية، الجامعة التكنو قسم هندسة النفط والغاز، 2 الخالصة ي ظل فيعد توصيف الخزان جانًبا مهًما لفهم كيفية توزيع خواص التكوين والسوائل في جميع أنحاء المكمن يع ثالثي األبعاد يستخدم للتنبؤ بتوز مكمني ستساعد هذه المعرفة في بناء نموذج. وجود تغايرات التكوين تدفق إحدى الطرق التي تم استخدامها بنجاح لتوصيف المكمن هي وحدة ال. المسامية والنفاذية وتدفق السوائل منطقة تتميز كل. تعتبر وحدة التدفق الهيدروليكي أداة فعالة لتقسيم الخزان إلى مناطق مختلفة. الهيدروليكي ي فهوم الذيرتبط الم. التي تميزها عن المناطق المجاورة األخرى ( روفيزيائية والجيولوجيةالبت)بخصائصها الخاصة وليكي بكل وحدة تدفق هيدر يتميز هذا المعامل الخاص .تم إنشاؤه لوحدة التدفق بما يسمى مؤشر منطقة التدفق . فققة التدخدام طريقة مؤشر منطعالوة على ذلك ، يمكن تقدير النفاذية بنجاح باست. بعالقات المسامية والنفاذية خل يوضح عمل هذا البحث أنه وفًقا لطريقة مؤشر منطقة التدفق ، تم تمييز أربع وحدات تدفق هيدروليكي دا والتي تقابل نوع الصخورالجيرية ( الصخور ذات الجودة الرديئةhfu 1حيث تمثل )، ن الخصيبتكوي الصخورذات الجودة المتوسطة والتي تقابل نوع الصخور الحيرية ( تمثل hfu 2المضغوطة والطباشيرية، ) خر ( تمثل الصخور ذات جودة جيدة والتي تقابل نوع الصخور الجيرية المسامية، وتعتبر آ hfu 3الحجرية، ) ( هي صخور المكمن ذات الجودة الممتازة والتي تقابل نوع الصخور الجيريةhfu 4وحدة تدفق هيدروليكي ) ،روليكيلنفاذية لكل وحدة تدفق هيدتم تقدير النفاذية باستخدام المعادلة الناتجة عن المسامية وا .المتشققة ، تعتبر خيًراأ .٪0.96وبمقارنة قيم النفاذية المقدرة مع نفاذية اللباب، كانت قيمة معامل االرتباط عالية وتساوي ها بقدرة ية المهيدروليكي للمكمن، وتعتبر النفاذطريقة مؤشر منطقة التدفق طريقة فعالة لتحديد وحدة التدفق ال ت قياسا ، لذلك يمكن تطبيق معادالت النفاذية الناتجة على اآلبار واالعماق غير المتاح بهادقيقة وموثوق بها .لباب الخصيب. تكوين ،تقدير النفاذية ،مؤشر منطقة التدفق، وحدة التدفق الهيدروليكي ،توصيف المكمن الكلمات الدالة: available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.20 no.4 (december 2019) 21 – 25 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: marwan hussien, email: marwanhussien294@gmail.com , name: hayder abdul hameed, email: hayderabdulhameed@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. biodiesel production from used vegetable oil (sunflower cooking oil) using eggshell as bio catalyst marwan hussien and hayder abdul hameed college of engineering-university of baghdad abstract bio-diesel is an attractive fuel fordiesel engines. the feedstock for bio-diesel production is usually vegetable oil, waste cooking oil, or animal fats. this work provides an overview concerning bio-diesel production. also, this work focuses on the commercial production of biodiesel. the objective is to study the influence of these parameters on the yield of produced. the biodiesel production affecting by many parameters such s alcohol ratio (5%, 10%,15 %, 20%,25%,30%35% vol.), catalyst loading (5,10,15,20,25) g,temperature (45,50,55,60,65,70,75)°c,reaction time (0-6) h, mixing rate (400-1000) rpm. the maximum bio-diesel production yield (95%) was obtained using 20% methanol ratio and 15g biocatalyst at 60°c. keywords: biodiesel, waste cooking oil, transesterification, methyl esters; renewable energy, diesel, waste vegetable oil received on 12/03/2019, accepted on 21/05/2019, published on 30/12/1029 https://doi.org/10.31699/ijcpe.2019.4.4 1introduction bio-diesel has become an integral part of the discussion of renewable energy sources. it was produced or refined from used vegetable oil, though each with different degrees of difficulty and involvement [1]. bio-diesel can be used in diesel-fueled vehicles without any changesinto engines. moreover, bio-diesel can be mixed with petroleum’s diesel to create different grade off fuel that arelabeled based on percentage of bio-diesel in the blends; for example, b10 is 10% bio-diesel, 90% petroleumdiesel. this means that in times of bio-diesel inadequacy, vehicless can use amix of fuel and still function the same way[2]. bio-diesel has advantage in terms of its flexibility and applicability. it holds great potential as an alternatives fuel. bio-diesel is created from aniemal or vegetables oil that is modiafied through a proacess called transesterification, during which triglycerides in the oil are coniverted to meethyl and fethyl esters and g-glycerin [3]. bio-diesel effected on co2 emissions and reduced it. biodiesel is studied because we need to reduce consumption of nonrenewable fossil fuels [4][1]. biodiesel can be defined as fatty acid methyl esters (fame) derived from the transesterificationof triglycerides (vegetable oils or animal fats) with alcohol and suitable catalyst. biodieselcan be produced from different triglyceride sources such as vegetable oils (that can be edible, non-edible or wasteoils) and animal fats (mostly edible fats or waste fats) [11]. the idea of using alternative fuels has been widely spreading for many years now as a replacement for fossil fuels. the importanceof this idea came from the large scale of utilization of fossil fuels in mechanical power generation various sectors, like agriculture,commercial, domestic and transport, also the fact of the continuousrise in fuels cost and their eventual vanish [12]. the advantage of biodiesel is a renewable resource, biodegradable, nontoxic fuel,a high cetane number, good lubricity, less gas emissions, sulphur free, carbon neutral and carbon dioxide (co2) is very small amount emission in the atmosphere. on the other hand, wastecooking oils are potential alternatives for diesel engines due to their nature [6][3]. the work of this research worked with many experiments to producing biodiesel from sunflower oil [5].methanol is used as alcohols and eggshell is selected as catalyst. 2materials and methods 2.1. feedstock waste vegetable oil (wvo) ways collected from the staff restaurant, in al-hilla. it was pre-treatment process by using two steps (filtration) and (dehydration) then it was filtered using filter paper (20µm) in order to remove impurity. after that it was dehydrated using a low pressure, in order to remove trace of water content present in oil. the characteristics of waste vegetable oil were conducted by using tlc &gc (baghdad university). https://doi.org/10.31699/ijcpe.2019.4.4 m. h. and h. abdul hameed / iraqi journal of chemical and petroleum engineering 20,4 (2019) 21 25 22 2.2. transesterification process experiments were conducted by using a reflux fitted system (fig. 1 a, b) the mixture of wastevegetable oil, methanol and catalyst were added to a 2000ml necked flask and submerged in a water bath at seven different temperatures (45, 50, 55 ,60 ,65 ,70 75)°c. the catalyst loading for this project were taken as (5, 10,15, 20, 25) g with constant volume of oil of 1000 ml. and methanol ratioswere taken as (5,10,15,20,25,30,35) %.the rate speed of agitation is 700 rpm remained constant. (a) (b) fig. 1. a reflux fitted system, b reflux fitted system 2.3. experimental procedure methyl ester was synthesized in a 2000ml boiling flask, four boiling flasks each flask having a different molar ratio and catalyst concentration while maintaining a constant temperature and agitation speed. the first experiment was kept at 60°c flasks with 15 g catalyst loading, and 20 % methanol and 1000 ml of waste vegetable oil, adding 1000 ml of waste vegetable oil in flask. the reaction time was 6h. after collection of the mixture, the sample was left to cool down for 10-15min, after which the two-phase (glycerin and bio diesel) system was carefully separated. the bottom layer of the system consisted of glycerin, while the top layer was made up of a mixture of methyl esters, unreactive methanol and intermediates see fig. 2. fig. 2. two phase glycerin and biodiesel produced 2.4 product estimation the yield and conversion were calculated as follows: ( ) (1) 3results and discussion 3.1. biocatalyst loading effecting on yield fig. 3 shows the effect of bio-catalyst loading on biodiesel yield, the figure shows low yield (70%) was obtained with high catalyst loading (25g of biocatalyst), which was insufficient catalyst to completion in the formation of methyl ester. higher bio-diesel yield (96%) was observed at an optimum concentration of (15g) catalyst loading. while at (10&20) g catalyst the biodiesel yield was lower. reaction rates increased as reactants occupied more catalytic sites until saturation was reached. 3.2. effect of temperature fig. 4 shows the effect of temperature on bio diesel yield, the figure shows that the best bio-diesel yield was founded at 60°c with a yield 95% under optimal conditions (catalyst loading 15 g, 20% methanol). in this current research, when temperature of the reaction increased to 60°cwas obtained optimum biodiesel yield. m. h. and h. abdul hameed / iraqi journal of chemical and petroleum engineering 20,4 (2019) 21 25 22 increasing the temperature beyond 60°c resulted in a decrease in the production because the reaction occurring beyond boiling point of methanol (64.7 °c) resulted in its continuous vaporization. hence it remained in the gas phase in the reflux, causing a decreasein methanol in the reaction media [9]. 3.3. effect methanol molar ratio fig. 5 shows the effect of different methanol ratio on bio diesel yield, the figure shows that the best bio-diesel yield was observed at (20%) of methanol that is 95%. the yield decreased significantly to70%, at a methanol ratio of 5%. this is due to the dilution effect of methanol and the interference between the high methanol ratio and the catalyst. there a subsequent increase in solubility and a decrease in the separation of glycerin and methyl ester [10]. fig. 3. effect of catalyst loading (bio) on bio-diesel yield fig. 4. temperature effecting on bio-diesel yield fig. 5. effect of methanol ratio on bio-diesel yield 3.4. effected of reaction time onbio-diesel yield. fig. 6 shows how the reaction time affected on biodieselyield when using biocatalyst (15 g), temperature 60°c and 20% methanol. the best yield 95%was obtained at 4 hours at catalyst (15 g) and methanol (20% vol.) as can be seen in figure 5. the bio-diesel yield was increased by increasing reaction from 1 to 4 hours. reaction time for the transesterification increases with increases the conversion rate of bio-diesel had observed with the increasing of time up to 4 h, after 4h there was decreasing in the bio-diesel yield. therefore, optimum reaction time was 4h. 3.5. effect of mixing on bio-diesel yield fig.6 shows the effect of differentmixing on yield(4001000) rpm , it can be see figure 6. the bio-diesel yield produced increased from 65% to 95% whenrate of mixing increasing from 400 to700 rpm and then decrease below 700 rpm. fig. 6. effect of reaction time on bio-diesel yield m. h. and h. abdul hameed / iraqi journal of chemical and petroleum engineering 20,4 (2019) 21 25 22 fig. 7. effected rate of mixing on bio-diesel yield 4conclusions the aim of this project was to assess biodiesel production from cooking used oil in the presence bio catalyst (eggshell). five factors were investigated oil/methanol ratio, catalyst, reaction time, mixing rate and temperature in order to optimize the process. the best reaction conditions obtained were methanol/oil r ratio (20% vol.), catalyst amount (15g of egg shell), time of reaction (4hr), rate of mixing (700 rpm) and temperature (60°c). it was assumed that the catalyst was used in sufficient amount with respect to oil in order to shift the reaction toward the formation of methyl ester. references [1] atadashi, i.m., aroua, m.k., abdul aziz, a.r. &sulaiman, n.m.n.,2011, “refining technologies for purification of crude biodiesel.” applied energy, vol.88, pp. 4239-4251. [2] kouzu m., hidaba j.s. ,2012, “transesterification of vegetable oil into biodiesel catalysed by cao: a review.” fuel, vol.93, pp.1-12. [3] zhang, y., dube, m.a, mclean, d.d. & kates, m., 2003,“biodiesel production from waste cooking oil: 1.” process design and technological assessment.” bioresource technology, vol.89, pp.1-16. [4] yaakob, z., mahammad, m., alherbawi, m. &alam, z. ,2013, “overview of the production of biodiesel from waste cooking oil.” renewable and sustainable energy review, vol.18, pp. 184-193. [5] glisic, s.b. &orlovic, a.m. ,2014, “review of biodiesel synthesis from waste oil under elevated pressure and temperature: phase equilibrium, reaction kinetics, process design and techno-economic study.” renewable and sustainable energy reviews, vol.31, pp.708-725. [6] elizer ahmed melo-espinosa, roman piloto rodriguez, roger sierens& sebastian verhelst, 2016,“emulsification of waste cooking oils and fatty acid distillates as diesel engine fuels: an attractive alternative.” international journal of sustainable energy planning and management, vol.09. [7] kotwal, m.s., niphadkar, p.s., deshpande, s.s., bokade, v.v. & joshi, p.n. ,2009, “transesterification of sunflower oil catalyzed by flash-based solid catalysts.” fuel, vol. 88, pp. 17731778. [8] lee, d.w., park, y.m. & lee, k.y., 2009, “heterogeneous based catalysts form transesterification in biodiesel synthesis.” springer science and business media, vol.13, pp. 6377. [9] birla, a., singh, b., upadhyay, s.n. & sharma, y.c. ,2012, “kinetics studies of synthesis of biodiesel from waste frying oil using heterogeneous catalyst derived from snail shell.” bioresource technology, vol.106, pp.95-100. [10] meher, l.c., vidya sugar, d. &naik, s.n., 2006, “technical aspects of biodiesel production by transesterification.” renewable and sustainable energy review, vol.10, pp. 248268. [11] mohammed abdul raqeeb and bhargavi r.,2015, “biodiesel production from waste cooking oil.” journal of chemical and pharmaceutical research, vol.12, pp.670-681. [12] elkady mf, ahmed zaatout& ola balbaa,2015,”production of biodiesel from waste vegetable oil via km micro-mixer.”petroleum & environmental biotechnology, vol.3. https://www.sciencedirect.com/science/article/abs/pii/s0306261911003242 https://www.sciencedirect.com/science/article/abs/pii/s0306261911003242 https://www.sciencedirect.com/science/article/abs/pii/s0306261911003242 https://www.sciencedirect.com/science/article/abs/pii/s0306261911003242 https://www.sciencedirect.com/science/article/pii/s0016236111005552 https://www.sciencedirect.com/science/article/pii/s0016236111005552 https://www.sciencedirect.com/science/article/pii/s0016236111005552 https://www.sciencedirect.com/science/article/pii/s0960852403000403 https://www.sciencedirect.com/science/article/pii/s0960852403000403 https://www.sciencedirect.com/science/article/pii/s0960852403000403 https://www.sciencedirect.com/science/article/pii/s0960852403000403 https://www.sciencedirect.com/science/article/abs/pii/s1364032112005588 https://www.sciencedirect.com/science/article/abs/pii/s1364032112005588 https://www.sciencedirect.com/science/article/abs/pii/s1364032112005588 https://www.sciencedirect.com/science/article/abs/pii/s1364032112005588 https://www.sciencedirect.com/science/article/abs/pii/s1364032113008174 https://www.sciencedirect.com/science/article/abs/pii/s1364032113008174 https://www.sciencedirect.com/science/article/abs/pii/s1364032113008174 https://www.sciencedirect.com/science/article/abs/pii/s1364032113008174 https://www.sciencedirect.com/science/article/abs/pii/s1364032113008174 https://www.sciencedirect.com/science/article/abs/pii/s1364032113008174 https://journals.aau.dk/index.php/sepm/article/view/1171 https://journals.aau.dk/index.php/sepm/article/view/1171 https://journals.aau.dk/index.php/sepm/article/view/1171 https://journals.aau.dk/index.php/sepm/article/view/1171 https://journals.aau.dk/index.php/sepm/article/view/1171 https://journals.aau.dk/index.php/sepm/article/view/1171 https://www.sciencedirect.com/science/article/pii/s0016236109001719 https://www.sciencedirect.com/science/article/pii/s0016236109001719 https://www.sciencedirect.com/science/article/pii/s0016236109001719 https://www.sciencedirect.com/science/article/pii/s0016236109001719 https://www.sciencedirect.com/science/article/pii/s0016236109001719 https://link.springer.com/article/10.1007/s10563-009-9068-6 https://link.springer.com/article/10.1007/s10563-009-9068-6 https://link.springer.com/article/10.1007/s10563-009-9068-6 https://link.springer.com/article/10.1007/s10563-009-9068-6 https://www.sciencedirect.com/science/article/pii/s0960852411016762 https://www.sciencedirect.com/science/article/pii/s0960852411016762 https://www.sciencedirect.com/science/article/pii/s0960852411016762 https://www.sciencedirect.com/science/article/pii/s0960852411016762 https://www.sciencedirect.com/science/article/pii/s0960852411016762 https://www.sciencedirect.com/science/article/abs/pii/s1364032104001236 https://www.sciencedirect.com/science/article/abs/pii/s1364032104001236 https://www.sciencedirect.com/science/article/abs/pii/s1364032104001236 https://www.sciencedirect.com/science/article/abs/pii/s1364032104001236 https://www.hindawi.com/journals/jchem/2015/630168/abs/ https://www.hindawi.com/journals/jchem/2015/630168/abs/ https://www.hindawi.com/journals/jchem/2015/630168/abs/ https://www.hindawi.com/journals/jchem/2015/630168/abs/ m. h. and h. abdul hameed / iraqi journal of chemical and petroleum engineering 20,4 (2019) 21 25 22 انتاج الوقود الحيوي باستخدام زيوت الطبخ النباتية المستعملة مروان حسين و حيدر عبدالحميد جامعة بغداد-كمية اليندسة الخالصة ونستطيع انتاجو من الزيت النباتي المستخدم باستخدام عوامل مساعده الوقود الحيوي ميم لحل مشاكل الطاقة قشور البيض كعامل مساعد وكذالك استخدم ثالثة نسب من كحول الميثانول حيويو وفي ىذا البحث تم استخدام ي (% واستخدم ايضا في ىذا البحث عدة اوزان من العامل المساعد وى3553052552051551055وىي ) .( غم من قشور البيض2552051551055) 5كمية (%3553052552051551055)ان انتاج الوقود الحيوي يتأثر بعدة عوامل ميمة وىي نسبة الكحول ( درجة سيميزية 5 وقت التفاعل 75570565560555550545( غم 5الحرارة )2552051551055العامل المساعد ) (دورة/دقيقة . وفي ىذا البحث تم الحصول عمى اعمى كمية من 1000-400و معدل الخمط ) ( ساعة0-6) العامل المساعد الحيوي ودرجة حرارة غم من 15% ميثانول و 20% تحت ظروف 55الوقود الحيوي وىي درجة سيميزية. 60 الكممات الدالة: وقود حيوي5 زيت طبخ مستخدم5 الطاقة المتجددة iraqi journal of chemical and petroleum engineering vol.17 no.1 (march 2016) 3746 issn: 1997-4884 rheological evaluation of polymer (sav 10) for polymer flooding applications talib a. salih, safaa hussain sahi and omar k. hameed university of baghdad, petroleum engineering department abstract half of the oil production of the worldwide is a result of the water flooding project. but the main concern of this process is mobility control of the injected fluid, because the unfavorable mobility ratio leads to fingering effect. adding polymer to the injection water increase the water viscosity, therefore, the displacement will be more stable and have a greater sweep efficiency. using of polymer flooding has received more attention these days. polymer has great potential in the middle east region, especially in reservoir with high temperature and salinity. the main objective of this work is to show the effect of shear rate, salinity, temperature, polymer concentration on polymer viscosity and determine the target viscosity to further displacement experiments. polymer solution was prepared with two types of water (fresh water, brine). the reason of using two types of water is the ability of polymer to prepare by fresh water or brine. results from this study show that as the shear rate increases, polymer viscosity decreases. also, the results show that in spite of polymer viscosity decreased with increase in temperature and salinity, polymer (sav 10) shows that high temperatures have less effect on its viscosity at the same shear rate and has a salinity resistant up 200000 ppm. as polymer concentration increase, polymer viscosity increase until reach the target concentration which can be used for displacement experiments. it was found that the target concentration with viscosity 6.99 cp is 2000 ppm, which is closest to reservoir viscosity. key words: polymer solution, rheology, polymer flooding. introduction oil recovery stages can classify into three stages; primary, secondary and tertiary stage. in the primary stage, reservoir natural energy such as gas drive, water drive, or gravity drainage will displace oil into production well and up to the surface. during primary stage, the reservoir pressure will fall and will not be enough to recover more oil from the formation. water or gas is injected as a secondary stage to maintain the pressure of the reservoir and displace hydrocarbons toward the production well. the most common secondary recovery method is water flooding. however, the secondary recovery method still leaves behind a iraqi journal of chemical and petroleum engineering university of baghdad college of engineering rheological evaluation of polymer (sav 10) for polymer flooding applications 38 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net substantial amount of oil due to both incomplete sweep in heterogeneous reservoirs and residual oil saturation in the pores of the rock [1]. so, it became necessary to find other technologies to extract the remaining oil after secondary recovery processes. enhanced oil recovery (eor) was developed for this purpose. in the tertiary recovery method (eor), almost 30-60% of the original oil in place can be recovered which is high compared with primary and secondary recovery stages where the recovery factor is equal to 20-40% [2]. chemical eor processes which consider as a method of enhanced oil recovery play a key role to recover the remaining oil after the secondary recovery processes. there are different types of chemical eor depending on the type of fluid used such as: polymer, alkaline and surfactant. in this thesis, polymer flooding was used as chemical eor processes. polymer flooding is characterized by its possibility to use as secondary or tertiary recovery. when a polymer is added to water, solution viscosity increases due to high molecular weight of the polymer. adding polymer to the injected water leads to reduce the mobility ratio between water/oil, get favourable flood and improve oil displacement. also, polymer flooding is characterized by reducing the porous media permeability which leads to an increase in the areal and vertical sweep efficiency of the injected water and consequently, increases the oil recovery [3] when a polymer solution is injected into a reservoir, the flow velocity, which is related to shear rate, will alter from well bore to reservoir indepth; therefore, the polymer viscosity will also change from the near wellbore to reservoir in-depth correspondingly. polymer rheology in a porous media is also affected by polymer type, molecular weight, concentration, water salinity of the reservoir, and reservoir permeability. flow polymer solutions through a porous media is a complex topic, controlled by polymer rheology and retention behaviour, and is still not understood very well [1]. moawad et al., (2007) [4] studied the main factors that can be affected on the polymer viscosity such as shear rate, salinity, polymer concentration, temperature. the type of polymer which is used in their lab was biopolymer (polymer). their results show as follows: 1as shear rate increases, polymer viscosity decreases. 2the polymer viscosity decreases as the temperature increases at the same shear rate . 3no salinity effect on polymer viscosity. 4as polymer concentration increases, polymer viscosity increases. point 1, 2 and 3 can be seen in fig. (1). finally, they indicated that with this type of polymer can be used in reservoirs with high salinity and high temperature. zhu, et al., (2015) [5] in recent years, the need of re-injection produced water of oil field in chemical flooding incremented and it was necessary to develop polymer solutions to resistant high salinities. the development of salt tolerance polymer has been improved in china recently. through modification in molecular structure, improving backbone strength, enhancing the regularity of bulk molecule structure. talib a. salih, safaa hussain sahi and omar k. hameed -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 39 fig. 1, factors impact on polymer viscosity [1] by this way new types of polymer can be produced and have a better salt tolerance performance. the chemical and physical properties of these polymers could meet the requirements of polymer products in re-injection the produced water of oil field with high salinity. types of polymers polymers are long chain organic molecules made from joining together small molecules called monomers. they are flexible with high molecular weight ranging from 2 x10 6 to 21x10 6 g/mole [6]. two types of polymers mostly used in polymer flooding process are polyacrylamide (pam), in its partially hydrolyzed form (hpam) and xanthan. fig. (2) shows the polymer types and structures for xanthan, pam & hpam commonly used. fig. 2, polymers for enhanced oil recovery (eor) [6] hydrolyzed polyacrylamide (hapm) polyacrylamides are water soluble polymers used in polymer flood applications in its hydrolyzed form. hpam is a straight chain polymer that has acrylamide molecules as monomers as shown in fig. (3) polyacrylamides are the co-polymers of acrylic acid and acrylamide. rheological evaluation of polymer (sav 10) for polymer flooding applications 40 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net fig. 3, chemical structure of polyacrylamide not (hydrolyzed) [7] polyacrylamides used in flooding undergo partial hydrolysis, which causes the negatively charged carboxylic group (-coo-) to be scattered along the backbone of the chain. typical degrees of hydrolysis are 25 – 35% of the acrylamide monomers; that are chosen to optimize the specific properties of polymer solutions such as viscosity, solubility and retention. if the degree of hydrolysis is too large, its properties are very sensitive to salinity and hardness. if it is too small, the polymer will not be water soluble. the typical molecular weight of hpam used in polymer food is within the range of 2 – 20x10 6 g/mole. molecular structure of partially hydrolyzed polyacrylamide is shown in fig. (4) [8]. fig. 4, molecular structure of partially hydrolyzed polyacrylamide [8] the viscosity-increasing feature of hpam polymers is derived from the repulsive forces between polymer molecules and between the segments of the same molecule. this repulsion causes the molecules to lengthen and snag on other molecules, thus causing the viscosity to increase [9]. xanthan gum another widely used polymer, a biopolymer (polysaccharides), is xanthan gum (corn sugar gum). these polymers are formed from the polymerization of saccharide molecules, a bacterial fermentation process. the structure of a xanthan biopolymer is shown in fig. (5). xanthan gum has a more rigid structure and is quite resistant to mechanical degradation. these properties make it relatively insensitive to salinity and hardness. it is susceptible to bacterial attack after it has been injected into the reservoir. the polymer is relatively nonionic and, therefore, free of ionic shielding effects of hpam. molecular weights of xanthan biopolymer used in eor processes are in the range of 1 million to 15 million. xanthan is supplied as a dry powder or as a concentrated broth. it is often chosen for a field application when no fresh water is available for flooding. some permanent shear loss of viscosity could occur for polyacrylamide, but not for polysaccharide at the wellbore. however, the residual permeability reduction factor of polysaccharide polymers is low. other potential eor biopolymers are scleroglucan, simusan, alginate, etc. [10] and [11] talib a. salih, safaa hussain sahi and omar k. hameed -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 41 fig. 5, molecular structure of xanthan [10] experimental materials the following materials were used in the experimental work; polymer a commercial polymer (superpusher sav 10) was used in this study. superpusher sav10 is partially hydrolyzed polyacrylamide (hpam) supplied by snf floerger in a white powder. fig. (6) shows a polymer sample beaker. the main characteristics of (superpusher sav 10) are :  molecular weights range from 3 to 8 million daltons (g/mol .  wide range of anionicity (quantify).  nontoxic and nonbioaccumulative.  powder is safe and easy to handle excellent solubility.  stable up to 140°c, 200g/l of temperature and salinity respectively, (fig. (7)) [14]. brine sodium chloride (nacl) was used for preparing synthetic brine. brine solution was used for preparing polymer solutions. fig. 6, polymer sample beaker fig. 7, types of polymer according to salinity and temperature experimental procedure polymer preparation the polymer solution was prepared with two types of water:  fresh water, which consider as river water.  brine with concentration (160000 ppm) which consider as formation water. the purpose of using two types of water (brine, fresh water) is as follows: 1if the sources of fresh water are available, reservoir preconditioning with fresh water and no formation mineralogy problem, fresh water rheological evaluation of polymer (sav 10) for polymer flooding applications 42 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net can be used to prepare the polymer solution. 2if the sources of fresh water not available, reservoir not preconditioning with fresh water or formation mineralogy problem. therefore, brine can be used to prepare polymer solution. in many cases formation water preferred to prepare a polymer solution to avoid the treatment cost of fresh water. to prepare polymer solution, brine solution should be prepared first by dissolving required amount of sodium chloride (nacl) in the beaker fill with 1000ml demineralised water and then stirred by a magnetic stirrer for 20 minutes. in order to add polymer to the brine solution, the stirrer has to be set up at a speed approximately 500600 rpm to build a very strong vortex. then, the weighted polymer is added slowly by sprinkling it into the wall of the vortex to avoid agglomeration of polymer particles. after 3-6 min of mixing, the magnetic stirrer speed reduced to 300 400 rpm. finally, the solution is stirred for 3 hours. the mouth of the beaker was covered with an aluminium foil to prevent contact with air. magnetic stirrer come with a thermal plate used to heat the solution to improve the dissolution process. the same procedure was repeated for different polymer concentrations and salinities used for experimental work. fig. (8) shows the magnetic stirrer which used in polymer preparation. it should be pointed out that the same procedures were used to prepare polymer solution in fresh water without needing to procedure of preparing the brine solution. fig. 8, magnetic stirrers used in polymer preparation viscosity measurement most of polymers that used for enhanced oil recovery are characterized by their high viscosity yield. the purpose of using polymer is to increase the water injection viscosity which improves the sweep efficiency and increasing the oil recovery factor. factors impacting on the polymer viscosity such as shear rate, polymer concentrations, salinity and temperature should be studied to clarify the behaviour of the polymer viscosity in porous media. therefore, the effect of these factors on the polymer viscosity was measured as a function of shear rate by using a kinexus rheometer as shown in fig. (9). fig. 9, kinexus rheometer talib a. salih, safaa hussain sahi and omar k. hameed -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 43 results and discussions impact of different shear rates on polymer viscosity polymer solutions are classified as (pseudo plastic fluids) which exhibits a smaller resistance to flow as the shearing rate increases. the effect of different shear rates on the polymer viscosity was measured at 90oc. polymer concentration with 1500 ppm was used. fig. (10) shows the relationship between polymer viscosity and shear rate. from the fig. 10 its observed that at low shear rates polymer viscosity shows newtonian behaviour. from some critical rate (γc) as the shear rate increases the polymer viscosity decreases. this decreases in polymer viscosity is attributed to the structural characteristics of polymer chains, which are aligned along the flow streamlines with respect to the increase in shear rate (non-newtonian behaviour). fig. 10, impact of shear rate on viscosity [14] impact of different salinity on polymer viscosity usually oil reservoirs have brine as formation waters. one of the most common flaws of the polymer solution, to be applied for enhanced oil recovery, is its sensitivity to salinity. the salinity of water has a major impact on polymer viscosity. any change in the water salinity has a direct effect on polymer viscosity. when a polymer solution, as hpam, is tested under different salinity water, its anionic and cationic in the water cause an attraction/repulsion to polymer chain, which make it compressed or stretched. when it's exposed to the distilled or low salinity water, the electrostatic repulsion between anionic groups along the polymer chains would be unshielded and cause an extensive expansion of polymer molecules. the expansions of polymer molecules give the polymer a relative high viscosity and make it hard to pass through a porous medium. when it encounters the high salinity water, a double layer of electrolytes shield electrostatic repulsion which decreases the stretch between the polymer chain and the molecules and a low viscosity is produced at a high salt concentration. fig. (11) shows that polymer viscosity as a function of different shear rates, decreases as salt concentrations increase. fig. 11, effect of salt concentrations on polymer viscosity [14] rheological evaluation of polymer (sav 10) for polymer flooding applications 44 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net fig. (12) illustrates the stability of polymer viscosity under different salinity conditions and it was observed that polymer viscosity (sav 10) shows a resistance against salinity up to 200000 ppm. hence, sva 10 could be a suitable candidate for polymer flooding processes of reservoirs with high salinity concentration. fig. 12, stability of polymer viscosity [14] impact of different temperatures on polymer viscosity as mentioned previously, there are many parameters that effect on polymer viscosity. therefore, one of these parameters is reservoirs temperature. petroleum reservoirs are characterized by their high temperatures. most of the polymers viscosity, which are used in polymer flooding application decreases as temperature increase. in order to start with a polymer flooding project, reservoir temperature should be measured and choose a polymer product withstand the reservoir temperature to avoid thermal degradation. in this study, the effect of the temperature on the polymer viscosity was investigated at different shear rates. fig. (13) and (14) shows the effect of the temperature from 50 o c to 90°c on the polymer viscosity at concentration 1500 ppm. these figures show that as the temperature increases, polymer viscosity decreases at the same shear rate. the results in table (1) shows that the polymer (sva 10) can be used in reservoir with high temperature without missing its property and it will be stable up 120 o c. but the measurement was done up 90 o c because kinexus rheometer has a temperature range up 90 o c. fig. 13, effect of different temperatures on the polymer viscosity prepared in fresh water [14] fig. 14, effect of different temperatures on the polymer viscosity in brine [14] talib a. salih, safaa hussain sahi and omar k. hameed -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 45 table 1, polymer viscosity at different temperature [14] temperature o c polymer viscosity in fresh water cp @ 39 s-1 polymer viscosity in brine cp @ 39 s-1 50 20.62 5.44 60 15.6 5.4 70 14.61 4.5 80 14.5 4.01 90 14.4 3.75 effect of polymer concentration on polymer viscosity five polymer concentrations were investigated which are 500, 1000, 1500, 2000 and 2500 ppm to show the effect of polymer concentrations on polymer viscosity with different shear rates. for each experiment, the temperature was remained constant at 90oc. the results in fig. (15) and (16) show that the polymer viscosity increases as polymer concentration increases because the number of polymer chains increase in a given volume, which strongly interact with each other resulting in more friction affects which increases the viscosity. fig. 15, effect of polymer concentrations on polymer viscosity in fresh water [14] fig. 16, effect of polymer concentrations on polymer viscosity in brine [14] based on fig. (15) and (16), in order to determine the target polymer concentration for displacement tests, polymer concentration with viscosity closest to oil viscosity should be selected. oil with viscosity of 7 cp was used. therefore, polymer concentration with viscosity of 8.4 cp of 500 ppm was selected in case of the polymer solution prepared in fresh water. but in case of polymer solution prepared in brine, 6.985 cp polymer viscosity of 2000 ppm polymer concentration should be selected [12]. the tow viscosities are selected at shear rate of 8 s -1 . the reason of choosing 8 s -1 is that the displacement in the reservoir is considered to be 1-2 ft/day, which around 8 s -1 of shear rate [13] conclusion 1the polymer viscosity (sva 10) has been tested for different salinity and it was observed that, it's viscosity decreases as salinity concentration increases. 2the polymer viscosity (sva 10) shows a resistance against salinity up to 200000 ppm. hence, sva 10 could be a suitable candidate for polymer flooding processes of rheological evaluation of polymer (sav 10) for polymer flooding applications 46 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net reservoirs with high salinity concentration. 3the effect of the different temperatures on the polymer viscosity was investigated and as the temperature increases, polymer viscosity decreases at the same shear rate. 4results in table (1) show that polymer (sva 10) can be used in reservoir with high temperature without missing its property. 5as polymer concentration increase, polymer viscosity increase. nomenclature hpam: hydrolyzed poly acryl amide pam: polyacrylamide ppm: part per million eor: enhanced oil recovery tds: total dissolved solids nacl: sodium chloride rpm: revolutions per minute references 1sun, yongpeng, baojun bai, and laila saleh., (2012), "measurement and impact factors of polymer rheology in porous media". intech open access publisher. 2enhanced oil recovery/co2 injection. united states department of energy. [online] 2011. www.energy.gov. 3algharaib, meshal kh, abdullah fahad faleh alajmi, and ridha gharbi., (2011) "enhancing recovery in high salinity oil reservoirs through optimized polymer flood,"international petroleum technology conference, international petroleum technology conference. 4moawad, taha, emad elhomadhi, and ahmed gawish., (2007), "novel promising, high viscosifier, cheap, available and environmental friendly biopolymer (polymtea) for different applications at reservoir conditions under investigation part a: polymer properties", the seventh egyptian syrian conference in chemical and petroleum engineering, petroleum engineering volume, faculty of petroleum and mining engineering, suez, egypt, pp. 29-31. 5zhu, youyi, ming lei, and zhuoyan zhu., (2015) "development and performance of salt-resistant polymers for chemical flooding", spe middle east oil & gas show and conference, society of petroleum engineers. 6kasimbazi, gloria., (2014), "polymer flooding". 7shupe, russell d., (1981),"chemical stability of polyacrylamide polymers", journal of petroleum technology, vol. 33, pp.1-513. 8littmann, j., (1988), "polymer flooding", developments in petroleum science, vol 24, amsterdam, elsevier inc. 9pancharoen, monrawee., (2009), "physical properties of associative polymer solutions", diss. stanford university. 10sheng, james., (2010), "modern chemical enhanced oil recovery: theory and practice", gulf professional publishing. 11lake, l., (1989) "enhanced oil recovery", nj: prentical hall. 12lopes, l. f.; silveira, b. m. o.; moreno, r. b. z. l., (2014), " rheological evaluation of hpam fluids for eor applications", international journal of engineering & technology vol. 14 issue 3, pp.40. 13de melo, m.; lucas, e., (2008), "characterization and selection of polymers for future research on enhanced oil recovery", chemistry & chemical technology. 2, pp.295– 303. 14omar, k. h., “chemical flooding to increase oil recovery”, msc dissertation, university of baghdad, 2015. http://www.energy.gov/ available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.23 no.2 (june 2022) 27 – 33 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: baseem h. al-sabbagh, email: b.al-sabbagh@coeng.uobaghdad.udu.iq, name: nada n. abdulrazzaq, email: nnabdulrazzaq@coeng.uobaghdad.udu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. measuring dyes concentration using a low-cost visible-light spectrophotometer baseem h. al-sabbagh and nada n. abdulrazzaq university of baghdad, college of engineering, chemical engineering department, baghdad -iraq. abstract a low-cost, rgb led-based visible-light spectrophotometer was designed to measure dyes concentration. dyes are widely used as indicators or coloring agents in different applications and knowing their concentration is an essential part for many studies . the proposed spectrophotometer provides many functionalities that clones the traditional expensive spectrophotometers for a budged price under $50. it was aimed to provide a versatile tool for instructors and educators to teach their students the fundamental concepts behind spectrophotometry. malachite green, methyl red, and methyl orange dyes were chosen to be good samples to show the integrity of the proposed spectrophotometer in terms of accuracy, repeatability, and sensitivity as compared to a conventional measurement. keywords: 3d printing, arduino, color sensor, dyes, rgb led, visible-light spectrophotometer. received on 05/03/2022, accepted on 04/06/2022, published on 30/06/2022 https://doi.org/10.31699/ijcpe.2022.2.4 1introduction a spectrophotometer is a device that measures the intensity of light passing through a specified medium (usually a liquid) at a given wavelength. it was found that the intensity of the incident light depends on the distance being traveled by the light and the concentration of the absorbing medium. this fact was correlated clearly by beer-lambert law [1]. visible-light spectrophotometer uses the visible spectrum of electromagnetic radiation which has a wavelength approximately ranging from 380 up to 750 nm. spectrophotometers can also be made to cover the ultraviolet (190-380 nm) or near-infrared (7502500 nm) non-visible regions of the electromagnetic spectrum. in fact, many commercial spectrophotometers were designed to cover all the mentioned zones, tagged as uv-vis-nir spectrophotometers.[2–5] a typical spectrophotometer would be composed basically from four parts: (1) light source – covering the required wavelength of measurements; (2) monochromator – to decompose the light source into its basic components via a prism or a grating material after being collected by the collimator (lens assembly to concentrate the light); (3) slit – allowing the passage of the selected decomposed beam; (4) photocell to sense the intensity of the light beam after being passed through the absorbing medium. a rectangular container usually made of plastic or glass called a cuvette were used to hold the sample to be measured. the cuvette has two parallel transparent sides allowing the passage of the light through. the length between the sides affects the value of the measured absorbance (e.g. 10 mm in case of standard cuvettes). the cuvette should be placed into a dedicated holder in the measuring chamber in such a way that the transparent sides always face the light source. cuvettes must always be clean, free from fingerprints or any dirt to prevent any interference that can be a source of error (refer to fig. 1). all the parts were adjusted and calibrated carefully by the manufacturers to ensure measurement accuracy. off course, additional mechanical and electronic components were also included in their designs to achieve the target requirements [6–8]. fig. 1. components of a typical spectrophotometer to make a measurement, the intensity of light passing through solute free medium (called the blank) should be measured first. the ratio of the intensity in the presence (i) and absence of the chemical solute (i0) is called the transmittance (t). the amount of light being absorbed by the solute is called the absorbance (a) and it is related to the transmittance by the relation: http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:b.al-sabbagh@coeng.uobaghdad.udu.iq mailto:nnabdulrazzaq@coeng.uobaghdad.udu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2022.2.4 b. h. al-sabbagh and n. n. abdulrazzaq / iraqi journal of chemical and petroleum engineering 23,2 (2022) 27 33 28 a = log(1/𝑇) (1) multiplying both the nominator and denominator inside the logarithmic expression in equation 1 by 100, gives: a = 2  −  log(%𝑇) (2) spectrophotometers usually gives the operator the option to display the measurements results either by %t or by a. according to beer-lambert law, at low concentrations, the amount of light being absorbed by the absorbing medium is proportional linearly with its concentration according to some thresholds:[9] a =  b c (3) in which  is the molar attenuation coefficient (l/mol.cm) that reflects how far the medium species can attenuate the light, also known as absorptivity, b is the path length (cm), and c is the concentration of the absorbing species (mol/l). absorbance measurements can either be used to qualify or quantify chemical species. to qualify a given sample, absorption spectrum curve must be established. absorption spectrum is a plot that shows the relationship between the absorbance and the wavelengths scanned over the tested sample. the curve represents a characteristic feature for the absorbing species and the wavelength in which maximum absorbance (𝑚𝑎𝑥 ) occur is a key feature to identify the species. to quantify the concentration of the unknown samples, calibration curve should be constructed between sample already known concentrations and their absorbance. measurements should be carried out at a maximum absorbance wavelength (𝑚𝑎𝑥 ). a linear relationship should be established according to equation 3. unknown concentration can be obtained then by projecting a line from absorbance over the calibration curve and reads the corresponding concentration value from the other axis. the slope of the line represents the molar absorptivity times the path length, b. the path length value is determined from the cuvette light path which can range from 1 mm up to 100 mm depending on the application area of study. standard cuvettes have a light path length equal to 10 mm. spectrophotometers are extensively used devices and have broad applications in analytical chemistry, biochemistry, clinical chemistry, physics, food engineering, and water analysis.[10–13] however, these instruments are expensive, requires well trained and qualified operators, and they are generally large due to the size and arrangement of the optical filters and mechanical parts. so, they are not always authorized for students to carry out their measurements and calculations directly even in developed countries. if so, then they might do that after training or under supervision of authorized key person. manufacturers always try to enhance their spectrophotometers by reducing the sources of errors to the lowest possible, ensures the repeatability and accuracy of the measurements, and minimize the test cost. in the following section, a demonstration for a successful method applied widely for some species that can reduce the cost sharply and make the spectrophotometer-like device available for virtually every interested person. 2led based spectrophotometers light emitting diodes or leds are semiconductor devices that produces light when a voltage applied over their terminals. they are designed to work at different wavelengths so that variant light colors can be obtained. bi and tri color leds are also available in which two or three semiconductor substrates were installed in one single package (e.g. rgb leds usually produces red, green, and blue colors). leds have many advantages since they are cheap, small, efficient, reliable, have low power consumption, and highly stable long life light sources. leds are practically designed to produce light at a constant and narrow wavelength of approximately 25 nm wide. since the absorbance bands for a particular medium were found to be typically in the 100 nm range, it is possible find a corresponding led that falls within the molecular absorption range for a given medium.[14] this means that leds can be used as light sources instead of the expensive lamps used in conventional spectrophotometers for some particular wavelengths. under such possibility many spectrophotometers based on leds as light sources were developed[15–21] and the first reported one was stated by flaschka h., et al [22]. led-based spectrophotometers makes the education of spectroscopy much easier since many of the components required to build it were available either on the shelf or can be afforded for inexpensive prices [23,24]. 3d printers, emerged with the broad capabilities of smart phones also have their impact on making simple and inexpensive spectrophotometers [25–30]. from the practical view, many inexpensive led spectrophotometers can tackle money barriers in some specific purposes such as water analysis and monitoring[31–33], determination of metal ions[34,35], flow injection analysis (fia)[36], and kinetics [37]. 3experimental work 3.1. electronics and 3d printed parts like many conventional spectrophotometers, the proposed spectrophotometer has a dedicated lcd screen display, keypad to enter values and to select options, and a measuring chamber. the measuring chamber contains light source (rgb led), cuvette holder, and the color/light intensity sensor. all the required parts were shown in fig. 2 and the fully assembled device was shown in fig. 3. b. h. al-sabbagh and n. n. abdulrazzaq / iraqi journal of chemical and petroleum engineering 23,2 (2022) 27 33 29 fig. 2. electronics and 3d printed parts fig. 3. fully assembled spectrophotometer the rgb led model ysl-r1047cr4g3bw-f8 by yun sun led technology co., ltd. can source three different light colors of different wavelengths. according to the manufacturer, the led can source red, green, and blue colors at peak wavelengths of 625, 520, and 468 nm. the led have 10 mm diameter and a diffused domed top to ensure that light will propagate in all proposed directions with the same intensity. a current limiting resistor of 330 ohm was connected in series with each led so that approximately 8 ma will be consumed by the red color led and about 5 ma for both the green and blue leds. current measurements were taken by connecting lutron dm-9983g smart multimeter in series with each led. color sensor tcs34725 by adafruits was used as a photometer. it provides digital measurements for red, green, and blue color components and clear light as well. it also contains an ir blocking filter to overcome the interference of the uv light components in the incoming light. it can be supplied from 1.8-3.3 v and communicate with microcontrollers through the i2c bus protocol. the tcs34725 will measure the incident light components and measure its illuminance by: i = 0.2126𝑅 + 0.7152𝐺 + 0.0722𝐵 (4) the clear light component was cancelled since the designed spectrophotometer uses three color sources only (red, green, and blue). then, the absorbance can be then measured via: a = 𝑙𝑜𝑔 ( 𝐼0 𝐼 ) (5) in which i0 and i are the light intensity values for the blank and test sample respectively. 3d printed parts were designed using designspark mechanical free software and printed with anycubic i3 mega 3d printer. black pla filament (torwell technologies co., ltd) were used to print the bottom cover, main body, measuring chamber, lid, and electronics compartment to avoid any interference with external light sources. 4x4 matrix membrane keypad (uruktech electronics) and 2x16 lcd display module (uruktech electronics) were attached over the electronics compartment cover, printed in white color to add some cosmetics to the device. arduino uno development board was used to control the operation of the spectrophotometer. data received from the color sensor (through the i2c bus) will be represented in 16-bit for each component. this means that each color will have 216 (65536) different values! make the sensor so sensitive to any change in the color’s intensity. fig. 4 shows a schematic diagram for the circuit implemented in the design. fig. 4. circuit schematic diagram the design was aimed to be like conventional spectrophotometers but of course with a smaller size. the operator will be asked to select the color that its peak wavelength is close to the absorbance wavelength of the material to be measured. thus, the operator will select one wavelength at a time depending to the chosen led. according to the calibration samples supplied, the device will calculate the best line that fits the calibration carve and uses its parameters to calculate the concentration of the unknown samples. the flow-chart and operation of the device was shown in fig. 5. to the best available led-based spectrophotometers, the operator will have the opportunity to really simulate the work with real spectrophotometer with an easy-to-follow steps. b. h. al-sabbagh and n. n. abdulrazzaq / iraqi journal of chemical and petroleum engineering 23,2 (2022) 27 33 30 fig. 5. operation flowchart of the designed led-based spectrophotometer 3.2. preparation of dye solutions a microscopy grade malachite green, methyl red and methyl orange (thomas baker, mumbai, india) were used as test dye samples. malachite green and methyl orange have peak absorbance at 617 and 464 nm respectively. methyl red gives a peak absorbance at 520 nm in acidic media of ph 2.0. methyl red solution were acidified using few drops hydrochloric acid. five samples were prepared for each dye from stock solutions ranging from 0.5 up to 20 mg/l. 4results and discussion the led based spectrophotometer was tested to measure the concentration of three different dyes. generally, the led color (i.e. either red of green, or blue) that its wavelength is close to the wavelength of maximum absorbance for the dye will be selected. the measured value will be compared with that obtained by the biotech engineering uv-9200 spectrophotometer at maximum absorbance wavelength. since standard cuvette were used in the measurements which have a 1 cm path length, this would make the measurements to be compared directly. fig. 6 shows the calibration curve for the measuring of malachite green dye. there is about 32% loss in sensitivity as compared to the measured value at absorbance peak of 617 nm by uv-9002 spectrophotometer. fig. 6. calibration curve for malachite green dye less sensitivity loss (about 7.5%) were obtained in the case of methyl red calibration measurements as seen in fig. 7. this should be expected since the maximum absorbance for the methyl red matches the peak’s emission band of the green led. finally, the sensitivity loss was found to be approximately 15% in the case of methyl orange dye calibration curve as shown in fig. 8. fig. 7. calibration curve for methyl red dye b. h. al-sabbagh and n. n. abdulrazzaq / iraqi journal of chemical and petroleum engineering 23,2 (2022) 27 33 31 fig. 8. calibration curve for methyl orange dye the general trend as can be seen from fig. 6-8 is that there is always sensitivity loss in all measurements as compared to the conventional spectrophotometer measurements. sensitivity loss could be minimized once the led emission band is close to the maximum absorbance wavelength of the dyes. however, even in case of losing sensitivity, the accuracy of the measurement would not be affected. the r-squared values of the measurements were found to be mor than 0.99 in all over the measuring range for all dyes. linearities in fig. 6-8 were further examined with the aid of residual plots that is embedded inside each figure. these plots reveal that the observed measurements fall with 0.02 absorbance unit for methyl orange and within 0.08 absorbance unit for both malachite green and methyl red. this confirms the high linearity of the relationship between the concentration and the absorbance as measured for both the led based spectrophotometer and the uv-9200 spectrophotometer. the typical error[38], given by: typical error =  𝑁1/2 (6) where:  is the standard deviation and n is the number of repeated measurements, based on repeating each measurement three times was found to be 0.0026, 0.0007, and 0.0023 absorbance unit for malachite green, methyl red, and methyl orange, respectively. this typical error falls within the precision 0.001 absorbance unit stated by the uv-9002 spectrophotometer or even butter. so, the precision of the led based spectrophotometer is quite close to the conventional spectrophotometer standards. 5conclusions a low-cost spectrophotometer was developed to tackle the commercial high-cost spectrophotometers. the developed spectrophotometer uses a simple rgb led as source of light and color sensor as a photometer. it can be used to measure the concentration of some widely used dyes confirming that their maximum absorbance wavelength should be close enough to the emission band width of the led. the device shows less sensitivity than the commercial spectrophotometer, but this should not affect the reliability of the measurements in all cases studied. references [1] d.f. swinehart, the beer-lambert law, j. chem. educ. 39 (1962) 333–335. [2] j. zwinkels, light, electromagnetic spectrum, in: r. luo (ed.), encycl. color sci. technol., springer berlin heidelberg, berlin, heidelberg, 2015: pp. 1–8. [3] d. gonzález-morales, a. valencia, a. díaz-nuñez, m. fuentes-estrada, o. lópez-santos, o. garcíabeltrán, development of a low-cost uv-vis spectrophotometer and its application for the detection of mercuric ions assisted by chemosensors, sensors (switzerland). 20 (2020). [4] f.b. gonzaga, c. pasquini, a low cost short wave near infrared spectrophotometer: application for determination of quality parameters of diesel fuel, anal. chim. acta. 670 (2010) 92–97. [5] l. noui, j. hill, p.j. keay, r.y. wang, t. smith, k. yeung, g. habib, m. hoare, development of a high resolution uv spectrophotometer for at-line monitoring of bioprocesses, chem. eng. process. 41 (2002) 107–114. doi: 10.1016/s0255-2701(01)001222. [6] a.w.s. tarrant, optical measurements, 4th ed., elsevier, 2003. doi: 10.1016/b978-0-7506-83081.00028-0. [7] e. v. kvittingen, l. kvittingen, b.j. sjursnes, r. verley, simple and inexpensive uv-photometer using leds as both light source and detector, j. chem. educ. 93 (2016) 1814–1817. doi: 10.1021/acs.jchemed.6b00156. [8] c. burgess, the basis for good spectrophotometric uv&visible measurements, elsevier b.v., 2017. doi: 10.1016/b978-0-444-63897-7.00001-9. [9] a.y. tolbin, v.e. pushkarev, l.g. tomilova, n.s. zefirov, threshold concentration in the nonlinear absorbance law, phys. chem. chem. phys. 19 (2017) 12953–12958. doi: 10.1039/c7cp01514c. [10] e.s.p.b. v, m. blanco, h. iturriaga, s. maspoch, l.d.q. analitica, simultaneous determination of metal ions spectrophotometric determination of binary, ternary and quaternary mixtures of aluminium, iron, copper, titanium and nickel by extraction with 8-hydroxyquinoline, 226 (1989) 271–279. doi: 10.1016/s0003-2670(89)80009-1. [11] t.a. trumbo, e. schultz, m.g. borland, m.e. pugh, applied spectrophotometry: analysis of a biochemical mixture, biochem. mol. biol. educ. 41 (2013) 242–250. doi: 10.1002/bmb.20694. [12] t. atomssa, a.v. gholap, characterization of caffeine and determination of caffeine in tea leaves using uv-visible spectrometer, african j. pure appl. chem. 5 (2011) 1–8. https://pubs.acs.org/doi/pdf/10.1021/ed039p333 https://pubs.acs.org/doi/pdf/10.1021/ed039p333 https://link.springer.com/referenceworkentry/10.1007/978-3-642-27851-8_204-1?noaccess=true https://link.springer.com/referenceworkentry/10.1007/978-3-642-27851-8_204-1?noaccess=true https://link.springer.com/referenceworkentry/10.1007/978-3-642-27851-8_204-1?noaccess=true https://www.mdpi.com/1424-8220/20/3/906 https://www.mdpi.com/1424-8220/20/3/906 https://www.mdpi.com/1424-8220/20/3/906 https://www.mdpi.com/1424-8220/20/3/906 https://www.mdpi.com/1424-8220/20/3/906 https://www.mdpi.com/1424-8220/20/3/906 https://www.sciencedirect.com/science/article/abs/pii/s0003267010005507 https://www.sciencedirect.com/science/article/abs/pii/s0003267010005507 https://www.sciencedirect.com/science/article/abs/pii/s0003267010005507 https://www.sciencedirect.com/science/article/abs/pii/s0003267010005507 https://www.sciencedirect.com/science/article/abs/pii/s0255270101001222 https://www.sciencedirect.com/science/article/abs/pii/s0255270101001222 https://www.sciencedirect.com/science/article/abs/pii/s0255270101001222 https://www.sciencedirect.com/science/article/abs/pii/s0255270101001222 https://www.sciencedirect.com/science/article/abs/pii/s0255270101001222 https://www.sciencedirect.com/science/article/abs/pii/s0255270101001222 https://www.sciencedirect.com/science/article/pii/b9780750671231500259 https://www.sciencedirect.com/science/article/pii/b9780750671231500259 https://www.sciencedirect.com/science/article/pii/b9780750671231500259 https://pubs.acs.org/doi/abs/10.1021/acs.jchemed.6b00156 https://pubs.acs.org/doi/abs/10.1021/acs.jchemed.6b00156 https://pubs.acs.org/doi/abs/10.1021/acs.jchemed.6b00156 https://pubs.acs.org/doi/abs/10.1021/acs.jchemed.6b00156 https://pubs.acs.org/doi/abs/10.1021/acs.jchemed.6b00156 https://www.sciencedirect.com/science/article/pii/b9780323909945000149 https://www.sciencedirect.com/science/article/pii/b9780323909945000149 https://www.sciencedirect.com/science/article/pii/b9780323909945000149 https://pubs.rsc.org/en/content/articlelanding/2017/cp/c7cp01514c/unauth https://pubs.rsc.org/en/content/articlelanding/2017/cp/c7cp01514c/unauth https://pubs.rsc.org/en/content/articlelanding/2017/cp/c7cp01514c/unauth https://pubs.rsc.org/en/content/articlelanding/2017/cp/c7cp01514c/unauth https://www.sciencedirect.com/science/article/abs/pii/s0003267089800091 https://www.sciencedirect.com/science/article/abs/pii/s0003267089800091 https://www.sciencedirect.com/science/article/abs/pii/s0003267089800091 https://www.sciencedirect.com/science/article/abs/pii/s0003267089800091 https://www.sciencedirect.com/science/article/abs/pii/s0003267089800091 https://www.sciencedirect.com/science/article/abs/pii/s0003267089800091 https://www.sciencedirect.com/science/article/abs/pii/s0003267089800091 https://iubmb.onlinelibrary.wiley.com/doi/full/10.1002/bmb.20694 https://iubmb.onlinelibrary.wiley.com/doi/full/10.1002/bmb.20694 https://iubmb.onlinelibrary.wiley.com/doi/full/10.1002/bmb.20694 https://iubmb.onlinelibrary.wiley.com/doi/full/10.1002/bmb.20694 https://academicjournals.org/journal/ajpac/article-full-text-pdf/fe3679f2409 https://academicjournals.org/journal/ajpac/article-full-text-pdf/fe3679f2409 https://academicjournals.org/journal/ajpac/article-full-text-pdf/fe3679f2409 https://academicjournals.org/journal/ajpac/article-full-text-pdf/fe3679f2409 b. h. al-sabbagh and n. n. abdulrazzaq / iraqi journal of chemical and petroleum engineering 23,2 (2022) 27 33 32 [13] y. coque, e. touraud, o. thomas, on line spectrophotometric method for the monitoring of colour removal processes, dye. pigment. 54 (2002) 17–23. doi: 10.1016/s0143-7208(02)00026-8. [14] p.c. hauser, t.w.t. rupasinghe, n.e. cates, a multi-wavelength photometer based on light-emitting diodes, talanta. 42 (1995) 605–612. doi: 10.1016/0039-9140(95)01455-k. [15] k.a. mohammad, a. zekry, m. abouelatta, led based spectrophotometer can compete with conventional one, int. j. eng. technol. 4 (2015) 399. doi: 10.14419/ijet.v4i2.4504. [16] t.s. yeh, s.s. tseng, a low cost led based spectrometer, j. chinese chem. soc. 53 (2006) 1067– 1072. doi: 10.1002/jccs.200600142. [17] j. kim, a. kim, h. oh, b. goh, e. lee, j. kim, simple led spectrophotometer for analysis of color information, 26 (2015) 1773–1780. doi: 10.3233/bme-151478. [18] d. treichel, m.a. thal, m.j. samide, topics in chemical instrumentation applied electronics : construction of a simple spectrophotometer, j. chem. educ. 78 (2001) 1510–1512. doi: 10.1021/ed078p1510. [19] p. hauser, r. tan, a simple photometer based on a new tri-colour light-emitting diode, chim. int. j. chem. 49 (1995) 492–494. [20] j.r. hamilton, j.s. white, m.b. nakhleh, development of a low-cost four-color led photometer, 73 (1996) 1052–1054. [21] g. veras, e. cirino, w. silva, s. figueredo, c. soares, t. brito, s. ricardo, b. santos, talanta a portable , inexpensive and microcontrolled spectrophotometer based on white led as light source and cd media as diffraction grid, 77 (2009) 1155– 1159. doi: 10.1016/j.talanta.2008.08.014. [22] h. flaschka, c. mckeithan, r. barnes, light emitting diodes and phototransistors in photometric modules, anal. lett. 6 (1973) 585–594. doi: 10.1080/00032717308058708. [23] j.j. wang, j.r. rodríguez núñez, e.j. maxwell, w.r. algar, build your own photometer: a guidedinquiry experiment to introduce analytical instrumentation, j. chem. educ. 93 (2016) 166–171. doi: 10.1021/acs.jchemed.5b00426. [24] e.c. navarre, extensible interface for a compact spectrophotometer for teaching molecular absorption in the undergraduate laboratory, j. chem. educ. 97 (2020) 1500–1503. doi: 10.1021/acs.jchemed.9b01023. [25] b.s. hosker, demonstrating principles of spectrophotometry by constructing a simple, lowcost, functional spectrophotometer utilizing the light sensor on a smartphone, j. chem. educ. 95 (2018) 178–181. doi: 10.1021/acs.jchemed.7b00548. [26] e.k. grasse, m.h. torcasio, a.w. smith, teaching uv-vis spectroscopy with a 3d-printable smartphone spectrophotometer, j. chem. educ. 93 (2016) 146–151. doi: 10.1021/acs.jchemed.5b00654. [27] r. bogucki, m. greggila, p. mallory, j. feng, k. siman, b. khakipoor, h. king, a.w. smith, a 3dprintable dual beam spectrophotometer with multiplatform smartphone adaptor, j. chem. educ. 96 (2019) 1527–1531. doi: 10.1021/acs.jchemed.8b00870. [28] k. laganovska, a. zolotarjovs, m. vázquez, k. mc, j. liepins, h. ben-yoav, v. karitans, k. smits, hardware x portable low-cost open-source wireless spectrophotometer for fast and reliable measurements, hardwarex. 7 (2020) e00108. doi: 10.1016/j.ohx.2020.e00108. [29] g.c. anzalone, a.g. glover, j.m. pearce, opensource colorimeter, sensors (switzerland). 13 (2013) 5338–5346. doi: 10.3390/s130405338. [30] m.l. kovarik, j.r. clapis, k.a. romanopringle, review of student-built spectroscopy instrumentation projects, j. chem. educ. 97 (2020) 2185–2195. doi: 10.1021/acs.jchemed.0c00404. [31] b.j. place, activity analysis of iron in water using a simple led spectrophotometer, j. chem. educ. 96 (2019) 714–719. doi: 10.1021/acs.jchemed.8b00515. [32] d. carreres-prieto, j.t. garcía, f. cerdáncartagena, j. suardiaz-muro, performing calibration of transmittance by single rgb-led within the visible spectrum, sensors (switzerland). 20 (2020) 1–26. doi: 10.3390/s20123492. [33] d. carreres-prieto, j.t. garcía, f. cerdáncartagena, j. suardiaz-muro, spectroscopy transmittance by led calibration, sensors (switzerland). 19 (2019). doi: 10.3390/s19132951. [34] p.c. hauser, t.w.t. rupasinghe, simultaneous determination of metal ion concentrations in binary mixtures with a multi-led photometer, fresenius. j. anal. chem. 357 (1997) 1056–1060. doi: 10.1007/s002160050304. [35] p. gonzález, n. pérez, m. knochen, low cost analyzer for the determination of phosphorus based on open-source hardware and pulsed flows, quim. nova. 39 (2016) 305–309. doi: 10.5935/01004042.20160020. [36] n. gros, a novel type of tri-colour lightemitting-diode-based spectrometric detector for lowbudget flow-injection analysis, sensors. 7 (2007) 166– 184. doi: 10.3390/s7020166. [37] m. calcabrini, d. onna, exploring the gel state: optical determination of gelation times and transport properties of gels with an inexpensive 3dprinted spectrophotometer, j. chem. educ. 96 (2019) 116–123. doi: 10.1021/acs.jchemed.8b00529. [38] s.w. smith, the scientist & engineer’s guide to digital signal processing, second edi, california technical publishing, 1999. https://www.sciencedirect.com/science/article/abs/pii/s0143720802000268 https://www.sciencedirect.com/science/article/abs/pii/s0143720802000268 https://www.sciencedirect.com/science/article/abs/pii/s0143720802000268 https://www.sciencedirect.com/science/article/abs/pii/s0143720802000268 https://www.sciencedirect.com/science/article/abs/pii/003991409501455k https://www.sciencedirect.com/science/article/abs/pii/003991409501455k https://www.sciencedirect.com/science/article/abs/pii/003991409501455k https://www.sciencedirect.com/science/article/abs/pii/003991409501455k https://www.researchgate.net/profile/abdelhalim-zekry/publication/277450444_led_based_spectrophotometer_can_compete_with_conventional_one/links/60240a8992851c4ed562f518/led-based-spectrophotometer-can-compete-with-conventional-one.pdf https://www.researchgate.net/profile/abdelhalim-zekry/publication/277450444_led_based_spectrophotometer_can_compete_with_conventional_one/links/60240a8992851c4ed562f518/led-based-spectrophotometer-can-compete-with-conventional-one.pdf https://www.researchgate.net/profile/abdelhalim-zekry/publication/277450444_led_based_spectrophotometer_can_compete_with_conventional_one/links/60240a8992851c4ed562f518/led-based-spectrophotometer-can-compete-with-conventional-one.pdf https://www.researchgate.net/profile/abdelhalim-zekry/publication/277450444_led_based_spectrophotometer_can_compete_with_conventional_one/links/60240a8992851c4ed562f518/led-based-spectrophotometer-can-compete-with-conventional-one.pdf https://onlinelibrary.wiley.com/doi/abs/10.1002/jccs.200600142 https://onlinelibrary.wiley.com/doi/abs/10.1002/jccs.200600142 https://onlinelibrary.wiley.com/doi/abs/10.1002/jccs.200600142 https://content.iospress.com/articles/bio-medical-materials-and-engineering/bme1478 https://content.iospress.com/articles/bio-medical-materials-and-engineering/bme1478 https://content.iospress.com/articles/bio-medical-materials-and-engineering/bme1478 https://content.iospress.com/articles/bio-medical-materials-and-engineering/bme1478 https://pubs.acs.org/doi/abs/10.1021/ed078p1510 https://pubs.acs.org/doi/abs/10.1021/ed078p1510 https://pubs.acs.org/doi/abs/10.1021/ed078p1510 https://pubs.acs.org/doi/abs/10.1021/ed078p1510 https://pubs.acs.org/doi/abs/10.1021/ed078p1510 https://ojs.chimia.ch/chimia/article/view/1995_492 https://ojs.chimia.ch/chimia/article/view/1995_492 https://ojs.chimia.ch/chimia/article/view/1995_492 https://pubs.acs.org/doi/abs/10.1021/ed073p1052 https://pubs.acs.org/doi/abs/10.1021/ed073p1052 https://pubs.acs.org/doi/abs/10.1021/ed073p1052 https://www.sciencedirect.com/science/article/abs/pii/s0039914008006218 https://www.sciencedirect.com/science/article/abs/pii/s0039914008006218 https://www.sciencedirect.com/science/article/abs/pii/s0039914008006218 https://www.sciencedirect.com/science/article/abs/pii/s0039914008006218 https://www.sciencedirect.com/science/article/abs/pii/s0039914008006218 https://www.sciencedirect.com/science/article/abs/pii/s0039914008006218 https://www.tandfonline.com/doi/abs/10.1080/00032717308058708 https://www.tandfonline.com/doi/abs/10.1080/00032717308058708 https://www.tandfonline.com/doi/abs/10.1080/00032717308058708 https://www.tandfonline.com/doi/abs/10.1080/00032717308058708 https://pubs.acs.org/doi/abs/10.1021/acs.jchemed.5b00426 https://pubs.acs.org/doi/abs/10.1021/acs.jchemed.5b00426 https://pubs.acs.org/doi/abs/10.1021/acs.jchemed.5b00426 https://pubs.acs.org/doi/abs/10.1021/acs.jchemed.5b00426 https://pubs.acs.org/doi/abs/10.1021/acs.jchemed.5b00426 https://pubs.acs.org/doi/full/10.1021/acs.jchemed.9b01023 https://pubs.acs.org/doi/full/10.1021/acs.jchemed.9b01023 https://pubs.acs.org/doi/full/10.1021/acs.jchemed.9b01023 https://pubs.acs.org/doi/full/10.1021/acs.jchemed.9b01023 https://pubs.acs.org/doi/full/10.1021/acs.jchemed.9b01023 https://pubs.acs.org/doi/abs/10.1021/acs.jchemed.7b00548 https://pubs.acs.org/doi/abs/10.1021/acs.jchemed.7b00548 https://pubs.acs.org/doi/abs/10.1021/acs.jchemed.7b00548 https://pubs.acs.org/doi/abs/10.1021/acs.jchemed.7b00548 https://pubs.acs.org/doi/abs/10.1021/acs.jchemed.7b00548 https://pubs.acs.org/doi/abs/10.1021/acs.jchemed.5b00654 https://pubs.acs.org/doi/abs/10.1021/acs.jchemed.5b00654 https://pubs.acs.org/doi/abs/10.1021/acs.jchemed.5b00654 https://pubs.acs.org/doi/abs/10.1021/acs.jchemed.5b00654 https://pubs.acs.org/doi/abs/10.1021/acs.jchemed.8b00870 https://pubs.acs.org/doi/abs/10.1021/acs.jchemed.8b00870 https://pubs.acs.org/doi/abs/10.1021/acs.jchemed.8b00870 https://pubs.acs.org/doi/abs/10.1021/acs.jchemed.8b00870 https://pubs.acs.org/doi/abs/10.1021/acs.jchemed.8b00870 https://pubs.acs.org/doi/abs/10.1021/acs.jchemed.8b00870 https://www.sciencedirect.com/science/article/pii/s246806722030016x https://www.sciencedirect.com/science/article/pii/s246806722030016x https://www.sciencedirect.com/science/article/pii/s246806722030016x https://www.sciencedirect.com/science/article/pii/s246806722030016x https://www.sciencedirect.com/science/article/pii/s246806722030016x https://www.sciencedirect.com/science/article/pii/s246806722030016x https://www.mdpi.com/1424-8220/13/4/5338?tb_iframe=true&width=370.8&height=658.8 https://www.mdpi.com/1424-8220/13/4/5338?tb_iframe=true&width=370.8&height=658.8 https://www.mdpi.com/1424-8220/13/4/5338?tb_iframe=true&width=370.8&height=658.8 https://pubs.acs.org/doi/full/10.1021/acs.jchemed.0c00404 https://pubs.acs.org/doi/full/10.1021/acs.jchemed.0c00404 https://pubs.acs.org/doi/full/10.1021/acs.jchemed.0c00404 https://pubs.acs.org/doi/full/10.1021/acs.jchemed.0c00404 https://pubs.acs.org/doi/abs/10.1021/acs.jchemed.8b00515 https://pubs.acs.org/doi/abs/10.1021/acs.jchemed.8b00515 https://pubs.acs.org/doi/abs/10.1021/acs.jchemed.8b00515 https://pubs.acs.org/doi/abs/10.1021/acs.jchemed.8b00515 https://www.mdpi.com/1424-8220/20/12/3492 https://www.mdpi.com/1424-8220/20/12/3492 https://www.mdpi.com/1424-8220/20/12/3492 https://www.mdpi.com/1424-8220/20/12/3492 https://www.mdpi.com/1424-8220/20/12/3492 https://www.mdpi.com/1424-8220/19/13/2951 https://www.mdpi.com/1424-8220/19/13/2951 https://www.mdpi.com/1424-8220/19/13/2951 https://www.mdpi.com/1424-8220/19/13/2951 https://link.springer.com/article/10.1007/s002160050304 https://link.springer.com/article/10.1007/s002160050304 https://link.springer.com/article/10.1007/s002160050304 https://link.springer.com/article/10.1007/s002160050304 https://link.springer.com/article/10.1007/s002160050304 https://www.scielo.br/j/qn/a/gmw7gmvr9vy58nx3jyxyjxn/abstract/?lang=en https://www.scielo.br/j/qn/a/gmw7gmvr9vy58nx3jyxyjxn/abstract/?lang=en https://www.scielo.br/j/qn/a/gmw7gmvr9vy58nx3jyxyjxn/abstract/?lang=en https://www.scielo.br/j/qn/a/gmw7gmvr9vy58nx3jyxyjxn/abstract/?lang=en https://www.scielo.br/j/qn/a/gmw7gmvr9vy58nx3jyxyjxn/abstract/?lang=en https://www.mdpi.com/1424-8220/7/2/166 https://www.mdpi.com/1424-8220/7/2/166 https://www.mdpi.com/1424-8220/7/2/166 https://www.mdpi.com/1424-8220/7/2/166 https://pubs.acs.org/doi/abs/10.1021/acs.jchemed.8b00529 https://pubs.acs.org/doi/abs/10.1021/acs.jchemed.8b00529 https://pubs.acs.org/doi/abs/10.1021/acs.jchemed.8b00529 https://pubs.acs.org/doi/abs/10.1021/acs.jchemed.8b00529 https://pubs.acs.org/doi/abs/10.1021/acs.jchemed.8b00529 b. h. al-sabbagh and n. n. abdulrazzaq / iraqi journal of chemical and petroleum engineering 23,2 (2022) 27 33 33 قياس تراكيز االصباغ باستخدام مطياف ضوئي واطئ الكلفة ندى نعوم عبد الرزاق و بسيم حفيظ فاضل جامعة بغداد. –كلية الهندسة –قسم الهندسة الكيمياوية الخالصة تم تصميم مطياف ضوئي واطئ الكلفة لقياس تراكيز االصباغ. تستعمل االصباغ في تطبيقات مختلفة، لذا فان معرفة تراكيزها يكون امرا حيويًا لمختلف أنواع الدراسات. المطياف المقترح يستعمل العديد من المزايا التي ًا. الهدف من بناء المطياف هو توفير أداة يوفرها المطياف التجاري لكن بكلفة تصل الى اقل من خمسون دوالر أخضر الطيفية. العلوم خصائص بعض فهم على تساعد والباحثين الطلبة قبل من االستعمال سهلة تعليمية الملكات، أحمر المثيل، وبرتقالي المثيل هي اصباغ انتخبت كنماذج لفحص جودة المطياف المقترح من ناحية ياس لغرض مقارنتها مع قياسات المطياف تجاري.ساسية القوحالدقة، والتكرار، طباعة ثالثية األبعاد ، أردوينو ، مستشعر ألوان ، أصباغ ، مقياس طيف الضوء المرئي الدالة: تالكلما iraqi journal of chemical and petroleum engineering vol.18 no.1 (march 2017) 37 46 issn: 1997-4884 investigation desulfurization method using air and zinc oxide/activated carbon composite nada s.ahmedzeki a , salah m. ali b and sarah r. al-karkhi a a chemical engineering department, college of engineering, university of baghdad, baghdad – iraq b petroleum research and development center, baghdad – iraq abstract in present work examined the oxidation desulfurization in batch system for model fuels with 2250 ppm sulfur content using air as the oxidant and zno/ac composite prepared by thermal co-precipitation method. different factors were studied such as composite loading 1, 1.5 and 2.5 g, temperature 25 o c, 30 o c and 40 o c and reaction time 30, 45 and 60 minutes. the optimum condition is obtained by using tauguchi experiential design for oxidation desulfurization of model fuel. the highest percent sulfur removal is about 33 at optimum conditions. the kinetic and effect of internal mass transfer were studied for oxidation desulfurization of model fuel, also an empirical kinetic model was calculated for model fuels at optimum condition, the apparent activation energy was found to be 16.724 kj/mol. key words: oxidation desulfurization; model fuel; kerosene; taguchi method; zno/ac composite; air oxidation. introduction petroleum refining industry has problems in production of low sulfur fuel as the new specification in the world [1]. the present records of the sulfur containing compounds in the fuel products available for use are as high as 3000 ppm while the past universal regulation is about 500 ppm [2] and current regulation is about 50 ppm [3] and for future new limit is less than 15 ppm [4]. the oxidation desulfurization is expected to solve great environmental problems occurring wherever different petroleum fractions are used. odor and toxic emissions due to the combustion of these fuels producing gases are expected to be reduced to low levels. hydrodesulfurization (hds) processes are used for removing aliphatic sulfur (rsr) and acyclic sulfur compounds such as dimethylsulfide, diethylsulfide, dibutylsulfide, diphenyl sulfide, thianisole, dibenzyl sulfide…etc. and less effective for the removal of cyclic sulfide such as thiophene, benzothiophene, dibenzothiophene, and 4, 6-methyl diabenzothiophene. in addition to hds process cannot exceed the 100 ppm of sulfur content although with severe conditions [5]. university of baghdad college of engineering iraqi journal of chemical and petroleum engineering investigation desulfurization method using air and zinc oxide/activated carbon composite 38 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net technologies that do not used hydrogen for catalytic decomposition of organosulfur compounds are discussed as a non-hds based desulfurization technologies, also these processes may be adopted as ultra-fine deep desulfurization for many petroleum fractions. direct selective oxidation of organosulfur compounds to sulfone, using oxygen or air rather than hydrogen to remove sulfur from refinery streams is attractive due to the availability of the reacting gas and its low price[5]. mild conditions of ods process, the temperature is ranged 40-100 o c and pressure is ranged is 12 bar [1] and also sometimes using room temperature and atmospheric pressure, made this process economic and novel, since the refractory sulfur compounds which are not removed in hds process can be oxidized to sulfones that removed by adsorption and extraction [6]. the main objective of the oxidant is to oxidize sulfur compounds from a fuel sample to corresponding sulfides or sulfones by adding electrophilic oxygen atom that converts sulfur compounds to polar form[7]. murata, s. et al., (2004) examined ods model diesel (dbt and benzene) fuel with sulfur content 3300 ppm and commercial diesel fuel with sulfur content 193 ppm by using aldehydes (n-octanol, n-hexanol, ndecanol and benzaldehyde) with molecular oxygen was examined in the presence of transition metal salts (cobalt, manganese, and nickel salts), the aldehydes oxidize by metal oxide to produce peracids and then dbt oxidize to sulfones by using peracids generated as a catalyst, sulfones can removed by extraction with polar solvents (acetonitrile), adsorption (silica or alumina) or/and extraction, with extraction by acetonitrile reduce sulfur content is 36 ppm ,adsorption over 20 g silica the sulfur reduction is 19 ppm and adsorption over 60 g alumina the sulfur reduction content to <5 ppm [8]. ma et al., (2007) studied ods of a model jet fuel (bt, 2-mbt, 5-mbt and dbt dissolved in n-decane) with sulfur content 412 ppm reduce to 2 ppm and a real jet fuel (jp-8) with sulfur content 717 ppm reduce to 126 ppm with molecular oxygen at ambient condition and an adsorption using fe (iii) nitrate and fe (iii) bromide with and without carbon support and also over an activated carbon [5]. sundaraman, et al., (2010) studied the of ods of commercial jet fuel (jp-8-520) with 520 ppm and commercial diesel fuel (lsd-41) with 41 ppm by using air as an oxidant for generating hydroperoxides with cuo as catalyst, and it was used to oxidize the sulfur compounds to sulfones around 99% and 80% of sulfur compound is oxidize in jet and diesel fuel respectively with moo3/sio2, then the sulfone formed is adsorbed by beta zeolite to ultra-low sulfur jet and diesel fuel [4]. imtiaz, et al., (2013) studied ods of model oil (thiophene, dbt, and 4-mdbt dissolved in n-heptane) with sulfur content 1275 ppm reduced to 57 ppm, and commercial oil (untreated naphtha, light gas oil, heavy gas oil and athabasca) using an airassisted performic acid oxidation with phase transfer catalyst (emulsion catalyst). sulfur removal rate for commercial oil including untreated naphtha was 83%, light gas oil 85%, heavy gas oil 68% and athabasca 64% [9]. nawaf, et al., (2015) studied ods of dbt in light gas oil (lgo) initial sulfur content 1000 ppm, in trickle bed reactor with homemade manganese oxide (mno2/γ-al2o3), the http://www.iasj.net/ nada s.ahmedzeki, salah m. ali and sarah r. al-karkhi -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 39 highest removal was 81.2% (188 ppm) at 200 o c [10]. this study can be applied as complementary process to hydrodesulfurization which can have an important role in producing fine or ultrafine fuel like gasoline or kerosene. in a cost point of view, this study is focusing on the use of local available materials or the conversion of these materials into new ones which are more effective. in present work zinc oxide loaded on activated carbon was studied with oxidation desulfurization of model fuel in presence of air as an oxidant in batch system. the design of experiments by the taguchi method was considered to find the optimum conditions, these optimum conditions examined with the iraqi kerosene in the same systems. experimental 1. materials kerosene with sulfur content 2850 ppm was supplied by the midland refineries company/al-dura refinery, and the model fuels dibenzothiophene c12h8s with purity 99% was supplied by himedia, india, dissolved in n-nonane with purity 99% was supplied by bdh chemicals, england. activated carbon was supplied by thomas baker/india, zinc nitrate hexahydrated zn(no3)2.6h20 with purity 98% was supplied by thomas baker, india and sodium hydroxide with purity 99% pellets was supplied by hopkin and williams, england. 2. zno/ac composite preparation zinc oxide loaded on activated carbon composite is prepared in thermal co-precipitation method. activated carbon is dried in oven for 1 h at 200 o c; to remove moisture. weighted 5 g of activated carbon powder and dispersed in 125 ml deionized water. this solution consisting of ac with deionized water was mixed by magnetic stirrer plate for one day for best dispersion. 0.9325 g of zinc nitrate hexahydrate was dissolved in 13 ml deionized water to obtain approximately 10 wt. % loading of zno. then add zinc nitrate solution slowly with mixing. the ph adjustment of the mixture was done by adding 1m of naoh solution until the ph reaches 8-9. the mixture was heated for 6 h at 90 o c by reflux with stirring. the product was cooled then filtrated by vacuum pump, washed, dried at 110 o c overnight and calcined the product for 3h at 250 o c. 3. experimental procedure the model fuel in present work is n-nonane with sulfur content of 2250 ppm made by dissolving appropriate amount of dbt. the ods experiments were carried out in 250 ml flask; air was bubbled at constant flow rate. uv-spectrophotometer instrument (genesys 10 uv) was used to calculate the concentration of dbt in n-nonane at 325 nm wave length. figure 1 shows the uvcalibration curve for concentration of dbt. the sulfur content of kerosene filtered was determined according to astm d7039 in the petroleum research and development center / ministry of oil by using the testing device (sulfur analyzer, sindie otg, usa). fig. 1: uv-calibration curve http://www.iasj.net/ investigation desulfurization method using air and zinc oxide/activated carbon composite 40 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net 4. characterization the crystalline phase of zinc oxide on the surface of activated carbon were examined by x-ray using cukα radiation (λ=1.54056α). data were collected within the 2θ range of 20 o and 80 o . the phase identification was achieved by comparing with reference data from the international center for diffraction data (icdd). xrd analysis was performed on bruker, d2 phaser (german 2010) and achieved in iraqi-german lab. the amount in weight percent of zinc oxide in prepared composite was determined by xray florescence using spectro xepos (german 2010). xrf analysis was achieved in iraqigerman lab. determination of prepared composite surface area and pore volume was achieved at petroleum research and development center / ministry of oil using bet method by thermo finnegan type, apparatus. bet surface area measurements were made by measuring n2 adsorption, the degasing temperature 200 o c for 1 h. atomic force microscopy gives the topography with high resolution by determining the interaction forces between the surface and a sharp tip mounted on a cantilever atomic force microscopy was achieved in chemistry science department / collage of science / university of baghdad. (spm-at 3000 / atomic force microscopy / angstromadvance inc., usa 2008 / contact model). results and discussion 1. characterization of zno/ac composite the xrd patterns of the raw activated carbon, showed the peaks of 2θ between 20-30 and 40-50, which is noisy disorderly indicates to amorphous carbon as shown in figure 2. also, found in literature [11]. fig. 2: xrd pattern of activated carbon for ac/zno, the clear peaks at 2θ of 34.438, 36.249 and 47.539 shown in figure 3 indicates a crystalline zno, and noisy background patterns refer to amorphous carbon. fig. 3: xrd pattern of ac/zno the xrf analysis shows the metal oxide composition for zinc oxide loading on the surface of the activated carbon. a measured zinc oxide was approximately 10 wt. %. the loading ratio was chosen 10 wt.% because the increasing in loading ratio causes the block of pore, and leads to decrease of surface area [12]. the surface area of prepared zno/ac composite was measured by bet method; the resulted values of surfaces area and pore volume are listed in table 1. 2 (degree) in te n s it y ( c o u n ts ) 20 24 28 32 36 40 44 48 52 56 60 64 68 72 76 80 0 400 800 1200 2 (degeree) in te n s it y ( c o u n ts ) 20 24 28 32 36 40 44 48 52 56 60 64 68 72 76 80 0 400 800 1200 1600 2000 2400 2800 http://www.iasj.net/ nada s.ahmedzeki, salah m. ali and sarah r. al-karkhi -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 41 table 1: surface area and pore volume property ac zno/ac surface area, m 2 /g 1005.5045 972.72 pore volume, cm 3 /g 0.6203 0.6114 a slight decrease in surface area of activated carbon was observed after loading of approximately 10 wt. % zinc oxide as listed in table 1. since the surface area is still high and near to the values of the original source, and sometimes the surface area and pore volume increase or be the same or near from original source in case of loading ratio less or equal 10 wt % , this is due to good dispersion of the metals oxides[13]. the average particle size was determined by afm. table 2 list the particles size distribution of activated carbon and zno/ac composite. figure 4 shows topographical surface images of activated carbon and zno/ac in two dimensional (2d) and three dimensional (3d) were obtained from afm analysis. table 2: particle size distribution composite avg. diameter (nm) ≤ 10vol % (nm) ≤ 50vol % (nm) ≤ 90vol % (nm) ac 93.84 50 90 140 ac/zno 104.72 60 90 150 a) 2d ac surface b) 3d ac surface c) 2d zno/ac surface d) 3d zno/ac surface fig. 4: afm test 2. analysis by taguchi method the taguchi method used to analysis the result by using mintab 17, the results are statistically using signal to noise ratio (s/n). different factors such as composite amount, temperature http://www.iasj.net/ investigation desulfurization method using air and zinc oxide/activated carbon composite 42 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net and time have been studied in order to find the optimum conditions for ods by air using zno/ac. table 3 lists the nine runs experiments with its results. s/n ratio is calculated using minitab 17. in the present work, s/n ratio the larger is better is considered. a larger s/n ratio corresponds to the best level condition. figure 5 shows effects of s/n ratio for all levels. table 3: results of taguchi experiment design for removal of sulfur compounds composite amount, g in 100 ml n-nonane temperature, o c time, min concentration, ppm % removal s/n ratio 1 25 30 1834.692366 18.45811707 25.3237 1 30 45 1660.432628 26.20299429 28.3670 1 40 60 1774.630416 21.12753707 26.4970 1.5 25 45 1702.956489 24.31304493 27.7168 1.5 30 60 1648.340156 26.74043752 28.5434 1.5 40 30 1797.85437 20.09536133 26.0619 2.5 25 60 1527.976008 32.0899552 30.1274 2.5 30 30 1621.592567 27.92921923 28.9212 2.5 40 45 1613.263977 28.29993788 29.0355 fig. 5: main effect plot of s/n ratios according to figure 5, the best levels can be determined depending on the lager value of s/n ratio, so that, the optimum conditions are composite loading 2.5g, 30 o c and 60 min. the order of effect of the factors is composite amount>time (min) temperature ( o c). figure 6 illustrates the percentage contribution of individual variables on variation in % sulfur removal. the amount of zinc oxide/ activated carbon have the highest effect compare to other, this because of increase of active surface area that adsorption the sulfur compounds as shown in figure 7. fig. 6: percentage contributions of individual variables http://www.iasj.net/ nada s.ahmedzeki, salah m. ali and sarah r. al-karkhi -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 43 fig. 7: effect of composite amount on dbt removal the temperature has the lowest effect compare to the effects of other factors, since the increasing temperature in present systems leads to loss of solvent as shown in figure 8. fig. 8: effect of temperature on dbt removal as the time increase the dbt removal increase due to increase amount of sulfur compounds remove, above 45 min, the sulfur removal slow decreases, which can be explained by reaching the maximum capacity as shown in figure 8. the sulfur compounds converts to corresponding sulfones that is more adsorbed than sulfides. the hydroperoxides that convert sulfide to sulfone increases as the time of process increase. the regression equation 1 that describes the general linear model for the present system obtained from analysis results by mintab 17 is: %dbt removal= 25.028 +xi1+ xi2+ xi3 …(1) the values of xi1, xi2 and xi3 for each factor and level are listed in table 4. xi1 represent the amount of composite for level i, xi2 represent the temperature for level i and xi3 represent time for level i. the r2 value for l9 run is 0.9648 which confirms a high quality agreement between the experimental and predicted values. the confirmation of model by comparison between dbt removal at best conditions of experiment and model equation, the experimental sulfur removal is 33% and the predicted is 33.115% gives the percent error is 0.3473%. figure 9 shows the relationship between experimental responses versus predicted. table 4: coefficient values of regression equation factors levels 1 2 3 xi1 -3.099 -1.312 4.411 xi2 -0.075 2.052 -1.98 xi3 -2.744 1.120 1.624 fig. 9: experimental versus predicted response 3. ods of kerosene fuel the kerosene fuel in present work with sulfur content 2850 ppm conducted ods experiments in same batch system at optimum conditions from tauguchi method analysis of model fuels (2.5g zno/ac, 30 o c and 60 min, the samples was test after filtered from composite. the total sulfur content determined is 2200 ppm, the sulfur removal percent 21% is less than model fuels at the same conditions because of the kerosene fuel contains in addition to sulfur compounds other aromatic compounds that have the same skeleton of sulfur compounds, http://www.iasj.net/ investigation desulfurization method using air and zinc oxide/activated carbon composite 44 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net this leads to decreased the selectivity to sulfur compounds [5]. 4. kinetic model for model fuel in present work, the kinetic model of ods by using air and zinc oxide/activated carbon was examined by pseudo-first order and pseudo second order kinetic rate equation to find the best kinetic model by comparison between correlation coefficient r 2 . equations ) represent the pseudo first order kinetic and equation 3 represents pseudo second order kinetic. … (2) … (3) figure 8 shows the effect of time on dbt removal at different temperature. the reaction rate constant was estimated through 30 min. table 5 list the comparison between two kinetic models, since pseudo second order kinetic show the good fit than the pseudo first order kinetics. table 5: the comparison between kinetics models temp. order 25 o c k r 2 n=1 0.011 0.9653 n=2 5e-6 0.9931 30 o c n=1 0.0122 0.9119 n=2 6e-6 0.9771 40 o c n=1 0.0158 0.7218 n=2 7e-6 0.8935 the activation energy determined from arrhenius equation 4, the slope gives the value activation energy 16.724 kj/mol and the intercept gives the value of pre-exponential factor 4.3678 g/mg. min. … (4) fig. 10: rate constant versus 1/t 5. pore diffusion the effect of internal mass transfer for the ods of dbt using air and zno/ac by calculating the thiele modulus (mt) as equation (5) [14]. √ … (5) for a second order equation the equation 5 reduced to equation 6: √ … (6) where the effective diffusivity can be evaluated from equation 7: … (7) in this work, zno/ac can be assumed sphere particles, for sphere , for zno/ac, the porosity εp are determined as 0.89, while, the tortuosity 𝝉p for activated carbon process range 1-12 the value of the tortuosity τp can be chosen as 3.5, since many researchers in the literature were chosen this value [15]. the molecular diffusion coefficient of the air in n-nonane is 0.0495 cm 2 /s at 67 o c was measured by cummings 1955 and by extrapolated the value was equal to 0.5789 cm 2 /s at 25 o c [16]. the diffusivity change with temperature as shown in equation 6 [17]. dab/dab0 = (t/t0) 3/2 … (8) http://www.iasj.net/ nada s.ahmedzeki, salah m. ali and sarah r. al-karkhi -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 45 the calculated thiele modulus values at different reaction temperature are listed in table 6. from the results list in table 6, it can be shown that, all values of thiele modulus (mt) are less than 0.4, and this indication that the effect of internal mass transfer on the overall reaction rate can be neglected and these results could be attributed to the small particle size that made pore diffusion resistance very small. table 6: thiele modulus calculation t k k g/mg.s dab cm 2 /s deff. cm 3 /cm solid.s mt 298.15 8.33e-08 0.05789 0.014721 1.50715e-07 303.15 1.00e-07 0.05936 0.015094 1.55455e-07 313.15 1.17e-07 0.06389 0.016246 1.56958e-07 conclusion the oxidation desulfurization can be achieved by using zno/ac and air as the oxidant. the optimum conditions for present system by using tauguchi method are composite loading 2.5 g, 30 o c and 60 min. percentage contribution for composite amount is 43.905%, time 34.927% and 21.167% for temperature. second order kinetics equation can be used to represent the system. the effect of internal mass transfer can be neglected. nomenclature symbol definition units a pre-exponential factor min -1 c0 initial dibenzothiophene concentration ppm ct dibenzothiophene concentration at any time ppm deff effective diffusivity coefficient cm 3 /cm solid.s dab molecular diffusion coefficient cm 2 /s e activation energy of the reaction kj/mol k rate constant of the reaction j/mol keff effective rate constant g/mg.s l characteristic length of the catalyst particles cm n order of the reaction greek letters εp porosity of the catalyst particles θ scattering or bragg angle τp tortuosity of the catalyst pores dimensionless numbers mt thiele modulus abbreviations references 1. d. liu, “catalytic oxidative desulfurization of a model diesel,” louisiana state university, 2010. 2. h. rang, j. kann, and v. oja, “advances in desulfurization research of liquid fuel,” oil shale, 2006. 3. h. x. zhang, j. j. gao, h. meng, y. z. lu, and c. x. li, “catalytic oxidative desulfurization of fuel ac activated carbon zno/ac zinc oxide /activated carbon afm atomic force microscope astm american standard test method dbt dibenzothiophene bet beunauer, emmett and teller ods oxidation desulfurization hds hydrodisulfurization icdd international center for diffraction data mbt methylbenzothiophene lgo light gas oil rsr mercaptan (rsr) xrf xray florescence xrd x-ray diffraction http://www.iasj.net/ investigation desulfurization method using air and zinc oxide/activated carbon composite 46 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net by h2o2 in situ produced via oxidation of 2-propanol,” ind. eng. chem. res., vol. 51, pp. 4868– 4874, 2012. 4. r. sundararaman, x. ma, and c. song, “oxidative desulfurization of jet and diesel fuels using hydroperoxide generated in situ by catalytic air oxidation,” ind. eng. chem. res., vol. 49, no. 12, pp. 5561–5568, 2010. 5. x. ma, a. zhou, and c. song, “a novel method for oxidative desulfurization of liquid hydrocarbon fuels based on catalytic oxidation using molecular oxygen coupled with selective adsorption,” catal. today, 2007. 6. t. v. rao, b. sain, s. kafola, b. r. nautiyal, k. sharma, s. m. nanoti, m. o. garg, and y. k. sharma, “oxidative desulfurization of hds diesel using the aldehyde / molecular oxygen oxidation system oxidative desulfurization of hds diesel using the aldehyde / molecular oxygen oxidation system,” vol. 50, no. 13, pp. 3420– 3424, 2007. 7. a. chica, a. corma, and m. e. domine, “catalytic oxidative desulfurization (ods) of diesel fuel on a continuous fixed-bed reactor,” j. catal., 2006. 8. s. murata, k. murata, k. kidena, and m. nomura, “a novel oxidative desulfurization system for diesel fuels with molecular oxygen in the presence of cobalt catalysts and aldehydes,” energy and fuels, 2004. 9. imtiaz, a. waqas, and i. muhammad, “desulfurization of liquid fuels using air assisted performic acid oxidation and emulsion catalyst,” chinese j. catal., vol. 34, no. 2, pp. 1839– 1847, 2013. 10. a. t. nawaf, s. a. gheni, a. t. jarullah, and i. m. mujtaba, “optimal design of a trickle bed reactor for light fuel oxidative desulfurization based on experiments and modeling,” energy & fuels, vol. 29, no. 5, pp. 3366–3376, 2015. 11. e. s. moosavi, s. a. dastgheib, and r. karimzadeh, “adsorption of thiophenic compounds from model diesel fuel using copper and nickel impregnated activated carbons,” energies, vol. 5, no. 10, pp. 4233– 4250, 2012. 12. j. chaichanawong, t. yamamoto, t. ohmori, and a. endo, “adsorptive desulfurization of bioethanol using activated carbon loaded with zinc oxide,” chem. eng. j., vol. 165, no. 1, pp. 218– 224, 2010. 13. s. p. hernandez, m. chiappero, n. russo, and d. fino, “a novel zno-based adsorbent for biogas purification in h2 production systems,” chem. eng. j., vol. 176– 177, pp. 272–279, 2011. 14. o. levenspiel, chemical reaction engineering, third edit. john wiley & sons, inc., 1999. 15. r. leyva-ramos and c. j. geankoplis, “diffusion in liquidfilled pores of activated carbon. i. pore volume diffusion,” can. j. chem. eng., vol. 72, pp. 262–271, 1994. 16. m. j. tang and m. kalberer, “supplement of compilation and evaluation of gas phase diffusion coefficients of reactive trace gases in the atmosphere : volume 2. diffusivities of organic compounds , pressure-normalised mean free paths , and average knudsen numbers for gas uptake calcu,” atmos. chem. phys., vol. 15, pp. 5585–5598, 2015. 17. r. b. bird and w. e. stewart, transport phenomena, second edi. john wiley & sons, inc., 2002. http://www.iasj.net/ iraqi journal of chemical and petroleum engineering vol.13 no.3 (september 2012) 17 issn: 1997-4884 polyvinyl alcohol – sodium nitrite water soluble composite as a corrosion inhibitor for mild steel in simulated cooling water aprael s. yaro and teeba m. darweesh department of chemical engineering, college of engineering, university of baghdad, iraq abstract the inhibitive action of polyvinyl alcohol –sodium nitrite (pvasn) composite on the corrosion of mild steel in simulated cooling water (scw) has been investigated by weight loss and potentiodynamic polarization. the effect of composite concentration (pva/sn) , ph, and exposure time on corrosion rate of mild steel were verified using 2 levels factorial design and surface response analysis through weight loss approach, while the electrochemical measurements were used to study the behavior of mild steel in (scw) with ph between 6 and 8 and in absence and presence of (pva) in solution containing different concentration of nano2. it was verified that all three main variables studied were statistically significant while their interaction is less pronounced. key words corrosion, polyvinyl alcohol, electrochemical measurements, weight loss method, polarization resistance, factorial design introduction valuable metals, such as mild steel, aluminum, copper and zinc are prone to corrosion when they are exposed to aggressive media (such as acids, bases ,and salt) [1]. therefore, there is a need to protect these metals against corrosion. the best option available for the protection of metals against corrosion has been found to be using of inhibitors [2]. the control of corrosion in recirculating cooling system is achieved by maintaining relatively small quantities of corrosion inhibitors in the cooling water. corrosion inhibitors retard the destruction of metals by chemical or electrochemical reactions with their environment. most of the inhibitors used in cooling water, are either alone or in combination with one or more other corrosion inhibitors [3]. the open recirculating system, with longer holding times at higher temperatures in the presence of higher dissolved solids concentrations, produces more sever corrosion, scaling, microbiological growth [4]. many inhibitors have been used in cooling water systems to solve these problems [5]. particularly, chromates and many other metals. however, the popularity of inhibitors containing heavy metals are diminishing, because of the concern over their toxic effects on aquatic and possibly animal life [6]. as a result, the current trend for inhibitor usage towards more environmentally friendly ‘green’ chemicals. the objective of this study iraqi journal of chemical and petroleum engineering university of baghdad college of engineering polyvinyl alcohol – sodium nitrite water soluble composite as a corrosion inhibitor for mild steel in simulated cooling water 2 ijcpe vol.13 no.3 (september 2012) -available online at: www.iasj.net was to develop environmentally acceptable multi-component inhibitors that inhibit corrosion. experimental method 1. material the working electrodes (1.99 x 0.99cm) used were made from carbon steel of 2 mm thickness. its composition was: (c= 0.06-0.18, mn= 0.27-0.63, p= 0.035, s= 0.035, si= 0.025). 2. solution the chemical composition of water solution used throughout the experiment was as given in table (1): table1, component and concentration ions of cooling water component concentration, ppm na + 441 cl 303 so4 -2 352 hco3 123 co3 -2 37 the test solution was prepared by dissolving 500 ppm nacl, 520 ppm na2so4, 170 ppm anhydrous nahco3, and 66 ppm na2co3 in one liter of distilled water. inhibitor solution was prepared by dissolving appropriate amount of(pvasn) in the scw. the ph of the solution was adjusted by using dilute solutions of naoh or hcl. 3. weight loss method the coupons were smoothened by emery paper, rinsed, dried with benzene, acetone and weighed on an digital scale. each of the coupon was designated and its initial weight was recorded. after each test, the specimen was washed with running tap water, scrubbed with a brush to remove corrosion products, then washed with tap water followed by distilled water and dried on clean tissue, immersed in benzene, dried, immersed in acetone, dried and left in a disicator over silica gel for one hour before weighting to the 4th decimal. 4. polarization technique the electrochemical cell was composed of platinum counter electrode, prepared mild steel specimen as working electrode and saturated calomel electrode (sce) as a reference electrode. the corrosion potential (ecorr) was measured against sce. the corrosion cell parts were joined to each other, then connected to potentiostat, ammeter and voltmeter. statring with cathodic polarization until reaching the corrosion potentials, then continuing with anodic polarization. the potential was changed (20-25mv) for each step after one minute period the current was recorded. results and discussion 1. weight loss method table (2) represents the low and high levels factor, the matrix of the factorial design and results are shown in tables (3 and 5) representing the three types of synthetic cooling water with increasing concentration factor respectively. table 2, original variable main variable original variable low level -1 high level +1 ph x1 6 8 pvasn, ppm x2 1000/250 2000/500 exposure time, hr x3 24 48 aprael s. yaro and teeba m. darweesh -available online at: www.iasj.net ijcpe vol.13 no.3 (september 2012) 3 table 3, 2 3 factorial design experiments with 2 levels for first concentration factor cooling water (scw1) no. ph pvasn time corrosion rate(gmd) 1 -1 -1 -1 6.7253 2 -1 +1 -1 3.3657 3 +1 -1 -1 4.3555 4 +1 +1 -1 1.7429 5 -1 -1 +1 9.7533 6 -1 +1 +1 5.4087 7 +1 -1 +1 7.2655 8 +1 +1 +1 2.9987 table 4, 2 3 factorial design experiments with 2 levels for second concentration factor cooling water (scw2) no. ph pvasn time corrosion rate(gmd) 1 -1 -1 -1 6.2379 2 -1 +1 -1 2.9363 3 +1 -1 -1 4.096 4 +1 +1 -1 1.5081 5 -1 -1 +1 9.3688 6 -1 +1 +1 4.7723 7 +1 -1 +1 6.5961 8 +1 +1 +1 2.7599 gmd=gm/m 2 .day table 5, 2 3 factorial design experiments with 2 levels for third concentration factor cooling water (scw3) no. ph pvasn time corrosion rate(gmd) 1 -1 -1 -1 5.8354 2 -1 +1 -1 2.6618 3 +1 -1 -1 3.8912 4 +1 +1 -1 1.064 5 -1 -1 +1 8.7308 6 -1 +1 +1 4.5734 7 +1 -1 +1 6.1797 8 +1 +1 +1 2.3656 the results were analyzed using the analysis of variance (anova) as appropriate to experimental design used. the regression equations obtained for the three types mentioned after analysis of variance gives the levels of corrosion rates of mild steel as function of different variables: ph, pva/nano2 ratio, and time of exposure. all terms regardless of their significance are included in the following equations for scw1, scw2, and scw3 respectively: y1=5.2–1.11x1–1.82x2 +1.15x3 +0.1x1x2 -0.115x1x3–0.33x2x3 …(1) y2=4.78–1.045x1–1.79x2+1.09x3 +0.185x1x2-0.15x1x3–0.31x2x3 …(2) y3=4.41–1.04x1–1.97x2+1.05x3 +0.087x1x2–0.153x1x3–0.245x2x3 …(3) where yi is the response, that is corrosion rate of mild steel, and x1, x2, and x3 are the coded values of the test variables, ph, pva/nano2 ratio, and exposure time respectively. according to equations 1, 2, and 3: 1. the main factors, ph, and the ratio of pva/nano2 have negative effects in all types of synthetic cooling water (i.e., decreases the corrosion rate) regardless of increasing the concentration factor from 1 to 3. keeping in mind that the ratio of pva/nano2 to be more pronounced in decreasing the corrosion rate than the ph. 2. the main factor, exposure time, have positive effect in all types of synthetic cooling water (i.e., increasing the corrosion rate), and its effect is almost the same regardless increasing the concentration factor. 2. polarization technique electrochemical cell was composed of platinum counter electrode, prepared mild steel specimen as working electrode and saturated calomel (sce) as a reference electrode. 2.1. open circute potential open circuit potential measurements were carried out for different types of synthetic cooling waters in absence and presence of nano2 as corrosion polyvinyl alcohol – sodium nitrite water soluble composite as a corrosion inhibitor for mild steel in simulated cooling water 4 ijcpe vol.13 no.3 (september 2012) -available online at: www.iasj.net inhibitor. it is apparent from fig. 1 through 3 that the open circuit potential of pure (blank) cooling water in the absence of inhibitor (i.e., nano2) decreases rapidly with time and finally reaches a steady state value. this variation of open circuit potential with time reveals the corrosivity of water on mild steel. however, in presence of nano2 corrosion inhibitor, the steady state potential is shifted more towards the noble direction by increasing the concentration of inhibitor. the effect of mixtures of constant concentration of nano2 and different concentration of pva on the steady state potential was investigated as shown in figures 1 through 3. it is quite obvious that these mixtures exhibit a pronounce effect on the steady state towards the noble potential compared to pure nano2 solution which shows a significant effect on the steady state potential shifted to more positive potential. this shifting explains the anodic nature of inhibitor and reveals the inhibiting of anodic reaction more than the cathodic one. fig.1, the relation between potential and time for mild steel in scw1 in theabsence and presence of different concentrations of nano2and with polyvinyl alcohol fig.2, the relation between potential and time for mild steel in scw2 in the absence and presence of different concentrations of nano2and with polyvinyl alcohol fig.3, the relation between potential and time for mild steel in scw3 in the absence and presence of different concentrations of nano2and with polyvinyl alcohol 2.2. electrochemical polarization studies the corrosion of steel in water is an electrochemical process, and therefore dose not obey ohm’s low v = i r. however, stern and geary showed theoretically that ohm’s low holds approximately if the polarization of the corrosion interface is constrained to be within -30, +30 mv of the rest potential. this investigation studies the extent to which the techniques “linear polarization resistance”, lpr, and “tafel extrapolation method” can be applied in order to obtain representative values of the corrosion rate in synthetic cooling water environment. aprael s. yaro and teeba m. darweesh -available online at: www.iasj.net ijcpe vol.13 no.3 (september 2012) 5 the polarization behavior of mild steel in synthetic cooling water scw1, scw2, and scw3 in presence and absence of inhibitor are shown in fig. 4 through 9 respectively. the electrochemical behavior of mild steel in simulated cooling water using polarization technique through monitoring the corrosion rates by linear polarization resistance technique and tafel extrapolation method are shown in fig. 10 and 11 respectively. fig.4, polarization curves of low carbon steel in scw1 in presence of nano2 only fig.5, polarization curves of low carbon steel in scw1 in presence of composite fig.6, polarization curves of low carbon steel in scw2 in presence of nano2 only fig.7, polarization curves of low carbon steel in scw2 in presence of composite fig.8, polarization curves of low carbon steel in scw3 in presence of nano2 only polyvinyl alcohol – sodium nitrite water soluble composite as a corrosion inhibitor for mild steel in simulated cooling water 6 ijcpe vol.13 no.3 (september 2012) -available online at: www.iasj.net fig.9, polarization curves of low carbon steel in scw2 in presence of composite fig.10, the relation between pva/sn ratio and icorr in different synthetic cooling water as calculated by resistance polarization approach fig.11, the relation between pva/sn ratio and icorr in different synthetic cooling water as calculated by tafel approach also, it is evident from fig. 12 and 13 that the inhibition efficiency increases with increase in inhibitor concentration in all scw’s under investigation. fig.12, the relation between inhibitor efficiency and pva/sn ratio in different synthetic cooling water using resistance polarization method fig.13, the relation between inhibitor efficiency and pva/sn ratio in different synthetic cooling water using tafel method 2.3. adsorption studies the fractional dependence of the surface covered, θ, at the concentration, c, of the inhibitor, was tested graphically by fitting it to langmuirs isotherm, which assumes that the solid surface contains a fixed number of adsorption sites and each site holds one adsorbed species. fig. 14 and 15 show linear plots for c/θ versus c. with r2= 0.993 for nano2 alone and r2= 0.996 for different concentration of pva in aprael s. yaro and teeba m. darweesh -available online at: www.iasj.net ijcpe vol.13 no.3 (september 2012) 7 synthetic cooling waters under investigation. fig.14, the relation between c/θ and c, inhibitor concentration of nano2 in synthetic cooling waters fig.15, the relation between c/θ and c, blend of inhibitor pvasn ratio in synthetic cooling waters conclusions 1. the inhibition action of pvasn ratio increase with increase of inhibitor concentration and the ph. 2. increasing the blend inhibitor concentration (pvasn) leads the open circuit potential to increase to more noble value, indicating the anodic nature of the blend used. 3. statistically, the interaction effect of the variables in multi-variable regression was found to be insignificant. 4. on the basis of gibbs free energy experimentally observed, physiosorption mechanism has been proposed for the inhibition action of the inhibitor blend through langmuir isotherm. references 1. ebenso e.e., eddy n.o., oldiongenyi a.o., 2009, “corrosion inhibition and adsorption properties of methocarbomal on mild steel in acidic media”, port. electrochemical acta 27(1),13-22. 2. eddy n.o., ekwumemgbo p.a., mamza p.p., “ethanol extract of terminalia catappa as green inhibitor for the corrosion of mild steel in sulfuric acid”, green chem. let. rev. 2(4), 223-231. 3. eswaran m.s., mathar p.k., “physico-chemical evaluation of corrosion inhibitor for carbon steel used in the cooling water system”, corrosion science,38, (1996),pp.1783-1790. 4. puckorius p.r., cunningham b., “cooling water technology advanced course”, international water conference, pittsburgh, 1997. 5. gehan k., locky a., rao m., “chemical treatment to control corrosion in open cooling water systems”. conf-ausralas. corros.assoc., corrosion /91, paper gi, nacb, houston, 1991.p15. 6. lake d.l., “approaching environmental acceptability in cooling water corrosion inhibition, corrosion prevention and control, 1998, p.113. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.23 no.1 (march 2022) 1 – 7 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: mustafa raad fahad, email: mustafa.r.fahad@gmail.com , name: basma abbas abdulmajeed, email: basma1957@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. effect of modified hybrid nanoparticles on the properties of base oil mustafa raad fahad a and basma abbas abdulmajeed b a petroleum research and development center prdc, ministry of oil, baghdad, iraq b chemical engineering department, university of baghdad, baghdad, iraq abstract nanomaterials have an excellent potential for improving the rheological and tribological properties of lubricating oil. in this study, oleic acid was used to surface-modify nanoparticles to enhance the dispersion and stability of nanofluid. the surface modification was conducted for inorganic nanoparticles (nps) tio₂ and cuo with oleic acid (oa) surfactant, where oleic acid could render the surface of tio2-cuo hydrophobic. fourier transform infrared spectroscopy (ftir), and scanning electron microscopy (sem) were used to characterize the surface modification of nps. the main objective of this study was to investigate the influence of adding modified tio₂ -cuo nps with weight ratio 1:1 on thermal-physical properties such as kinematic viscosity, viscosity index (vi), pour point, and flash point of iraqi base oil (40 stock) and nano-lubricating oil. the kinematic viscosity of base oil at 40 °c and 100°c increased with high concentrations of modified tio₂ -cuo nps. the highest value of vi of base oil 40 stock at 0.8 wt. % of modified tio₂ -cuo nps was 108.5. the results showed that the flashpoint value increased with the increased concentration of modified tio₂ -cuo nps of base oil 40, where the highest value was 220 °c. the pour point of nano lubricating oil base with 0.8 wt. % of modified tio₂ -cuo nps showed decreasing from -12 °c to -15 °c of base oil 40. keywords: oil 40 stock, lubricating oil, nanoparticles, oleic acid, viscosity index, flash point received on 30/01/2022, accepted on 05/03/2022, published on 30/03/2022 https://doi.org/10.31699/ijcpe.2022.1.1 1introduction the word (lubricating oil) relates to various products of hundreds of specific chemicals and additives and can be either mineral or synthetically. lubricating oil contains 80-90% of hydrocarbon petroleum distillates and 10-20% additives. mineral oil is more commonly used than synthetic oil [1]. improving environmental protection, durability, and fuel efficiency is a major focus in the automotive industry. new techniques are being developed, such as introducing new, less harmful materials and the controlled combustion of fuels. which manages the environmental harms caused by vehicles. the lubricant plays a crucial role in friction and wear reduction and is sometimes needed to perform other functions. it is useful as a heat-transfer medium in many applications. it eliminates heat from "hot spots" in sliding parts, thereby avoiding overheating losses such as cooling engine pistons, power-transmission systems, and metalworking operations [2]. several different forms of lubricants are used in machinery. these lubricants are used in gasoline and diesel engines containing various forms of chemical materials known as "additives", which are used to enhance the properties of these lubricants to give the best-operating conditions instance, the efficiency of lubricating oil in engines. in a lubricating device, where total isolation between two surfaces is achieved, the lubricant's viscosity becomes the parameter that governs the adhesion, abrasion, corrosion, and fatigue that cause various processes [3]. the base oil (natural and synthetic) typically cannot reach the required high-performance specifications without the use of advanced additives cannot reach the properties of high-performance lubricating oil without the aid of advanced additive technology [4]. the additives are the chemical component used to gain desirable base stocks that enhance existing properties. the properties that are deemed important are: viscosity, viscosity change with temperature (viscosity index), pour point, oxidation resistance, flash point, and boiling temperature [5], [6]. organo-molybdenum compounds and organo-zinc phosphate compounds are examples of such additives. whereas these additives are useful as modifiers of friction and wear, they may also have several drawbacks such as poor oil solubility, copper, lead to corrosion of the finished lubricant, increased sulfur, and phosphorus components level in the final lubricating oil. as a result, new types of additives can be used as replacements for traditional lubricant additives and improve the overall lubricant performance while being more environmentally friendly and compatible with pollution control devices used in automotive and diesel engines must be developed [7], [8]. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:mustafa.r.fahad@gmail.com mailto:basma1957@yahoo.com http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2022.1.1 m. r.fahad and b. a. abdulmajeed / iraqi journal of chemical and petroleum engineering 23,1 (2022) 1 7 2 in recent years, the use of nanoparticles as lubricant additives has grown steadily. many researchers showed that a nanoparticle-containing lubricant formulation, also known as a nano lubricant, reduced friction and wear. nano lubricants have the potential to solve many of the problems of traditional lubricants. the main benefits of using nano lubricants are that they are insensitive to temperature and have as there are fewer tribo-chemical reactions than traditional additives [8]–[11]. suspended nps make nanofluids (nfs) with average sizes of less than 100 nm in standard fluids like water, oil, and ethylene glycol. when dispersed homogenously and stably in fluids, a very small amount of nanoparticles will provide important changes in the thermal properties of the base fluid [12], [13]. nanomaterials (nms) are typically scattered in liquids at low concentrations to produce nfs. higher concentrations of nanoparticles in liquid can cause sedimentation because of their poor stability in fluids. nms are typically scattered in liquids at low concentrations to create nanofluids. higher concentrations of nps in the fluid can produce sedimentation because of their low stability in fluids. metal oxides like cuo, tio2, al2o3, zno, mgo, and sic are highly thermal conductivity nanoparticles.[14], [15]. in comparison to mono nanofluids, hybrid nfs are expected to replace basic nanofluids for various reasons, such as a larger absorption range, lower extinction, high thermal conductivity, and low frictional losses[16]. the potential for more progress in thermal conductivity and thermophysical properties of hybrid nanofluids compared to traditional nanofluids is one of several reasons why researchers were led to the use and analysis of these types of nanofluids [17]. several study results have shown that lubricating oil formulations containing nanoparticles, also known as nano-lubricants, decrease friction and wear. nano lubricants have always had the potential to solve many of the issues associated with traditional lubricants [9], [10]. in the current study, surface modification of inorganic nanoparticles work as an additive in organic liquid using an oleic acid surfactant to enhance the stability of nanolubricating oil and improve the rheology and tribology properties of two types of iraqi base oil (40 stock) by using modified hybrid tio2-cuo nps 2experimental work 2.1. materials in this work, nano copper oxide cuo and nano titanium (iv) oxide tio2 were purchased from (sky spring nanomaterials, inc. houston, usa) and (hongwu international group ltd., guangdong, china), respectively. oleic acid surfactant was purchased from (alpha chemika, india). the base oil (40-stock) was collected from (al-dura refinery, middle refineries company, baghdad, iraq). the nps properties are presented in table 1, and the base oil (40-stock) specifications are shown in table 2. table 1. specifications of tio2 and cuo nps specification tio cuo average diameter(nm) 71.14 73.09 colour white black purity (%) >99.9 99 surface area (m 2 /g) 119.9 50 pore volume (cm³/g) 0.237 0.1606 table 2. properties of base oil 60 stocks specification oil (40 stock) kinematic viscosity @ 40 c (cst) 61.163 kinematic viscosity @ 100 c (cst) 8.2209 viscosity index 102.6 density @15 (g/cm³) 0.8617 flash point (c) 226 pour point (c) -6 2.2. experimental procedures a. preparation of surface modification of nps preparation of surface modification of nps was completed by adding (1gm) oleic acid to 100ml of ethanol solvent. two grams of nps were added to the solution after homogenizing the solution with mixing using a magnetic stirrer. the solution was heated to 75 °c for two hours. after the reaction was over, the oven was used for 4 hours less than 80 °c to ensure all the ethanol was vaporized. then, it was washed with methanol to remove unreacted oleic acid. the sample was dried at 80 °c for 6 hours to produce modified nps oa/tio2 and oa/cuo. b. preparation of nano-lubricating oil modified nps were added to two base oil (40 stocks), for preparing nano lubricating oil. the modified tio2 and cuo nps were added directly as hybrid additives with a weight ratio of 1:1 to both base oil at different concentrations of (0.2, 0.5, 0.8, and 1% wt.). stable nano-lubricant is an essential need in this study. according to this, different methods were used, like a magnetic stirrer, ultrasonic probe, and surface modification. nano-lubricating oil was prepared by dispersing surface-modified nanoparticles into the base oil. the required amount of nps was weighed carefully using an accurate electronic balance. a magnetic stirrer was used to mix the nps with base oil for 2 hours. then an ultrasonic probe-type vcx 750 (sonics and materials inc., usa fitted out with a 13 mm diameter ti6al-4v alloy tip) was used at the operating conditions shown in table 3 to obtain high dispersion and prevent agglomeration of nps. sonication was carried out for each pulsed irradiation, alternating 5 s of t/on and 5 s of t/off. a water bath jacket was used to avoid overheating of the sample during ultrasonic dispersion. m. r.fahad and b. a. abdulmajeed / iraqi journal of chemical and petroleum engineering 23,1 (2022) 1 7 3 fig. 1 shows the photo of nano-lubricating oil by the ultrasonic probe. the general steps of the experimental work are represented in fig. 2. table 3. ultrasonic probe specifications the condition value power 60 %, 750w time 1 hr. temperature 40 °c frequency 20 khz sample quantity 100 ml fig. 1. dispersion of nps into lubricating oil by an ultrasonic probe fig. 2. flow diagram of the experimental work 3results and discussion 3.1. ft-ir characterization of modified tio2 and cuo nanoparticles. the ft-ir characterized oleic acid (oa) and nps in the range of 4000-500 cm -1 . fig. 3 shows the ft-ir of oleic acid. the peak at 1707cm -1 represents c=o stretching, and peaks around 2920 -2850 cm -1 are attributed to the long alkyl chain[18]–[21]. the ft-ir spectrum of tio2 fig. 4 and fig. 5 shows two curves. in curve (a) of figure (4), peaks around 450 and 750cm ˉ1 in the range of 400–800 cmˉ1 are contributed to anatase titania for pure tio2. the vibration absorption of the ti-o-ti links in tio2 nanoparticles is attributed to a large absorption band between 450 and 800 cm ˉ 1 (praveen et al., 2014). the observed peak at 3415 and 1633 cm⁻ ¹ refer to hydroxyl group –oh and water ti-oh [22]. in both curves (b) of fig. 4 and fig. 5, the adsorption peaks of 2924.09 and 2852.72 cm⁻ ¹ are attributed to oa's long alkyl groups and the absorption bands around 1710.8 attributed to carbonyl group c=o from oleic acid [23]. the absorption band around 542 cm⁻ ¹ as shown in curve (a) of fig. 5, refers to the cu–o functional group's vibrations, and the peak at 3448.7 and 3452 cm⁻ ¹ relate to the –oh group[24], [25]. in curves (b) of fig. 4, and fig. 5, the peaks around 2854 and 2924 cm–1 are attributed to ch2 and ch3 groups formed on the surface of nps. the carbonyl group at the peak of around 1710 cm -1 in oleic acid form is decreased sharply in these curves. the presence of carboxylate (-coo-) at peaks of around 14281550 cm-1 indicates the reaction of oleic acid and bonded on the surface of nps. and also the −oh groups on the surface of tio2, and cuo nps decreased in modified tio₂ and cuo nanoparticles. meanwhile, oa groups of carboxyl (cooh) reacted with hydroxyl (oh) groups to produce carboxylate in modified nps [20], [26]–[28]. fig. 3. ftir spectrum of pure oleic acid m. r.fahad and b. a. abdulmajeed / iraqi journal of chemical and petroleum engineering 23,1 (2022) 1 7 4 fig. 4. ftir spectrum of tio2 (a) and oa/ tio₂ (b) fig. 5. ftir spectrum of cuo (a) and oa/ cuo (b) 3.2. scanning electron microscopy (sem) of oleic acid / nps scanning electron microscopy (sem) is used to characterize the morphology of nanoparticles before and after modification. in fig. 6 (a) and (b), the images illustrate the morphology of unmodified tio2, cuo, and al2o3 nps, and they were fairly spherical. according to the images in fig. 6 (b) and (c), it can be seen that the dispersibility of modified nps was improved, and the pattern of modified nps appear a little hazy in the pictures, which indicates to coated of oa on the surface of nps[27], [29], [30]. fig. 6. fe-sem of unmodified nps (a) tio2, and (b) cuo, and modified nps (d) oa/ tio2, and (d) oa/ cuo 3.3. effect of addition modified tio2-cuo nps on the kinematic viscosity and viscosity index of nanolubricating oil viscosity is one of the essential properties of any lubricant, which is one of the most significant considerations when selecting oil for equipment. fig. 7 (a) and (b) demonstrate the influence of modified tio2 and cuo nps on the kinematic viscosity of base oil 40 stock at temperatures 40 °c and 100 °c, respectively. the viscosity increased slightly on increasing modified nps concentration at both temperatures. at high concentrations, the presence of larger, spherical particles within oil layers, which prevents movement, might explain increased viscosity [31]. the highest increase of viscosity was 2.9 %, 3.31 %, and 3.7 %, related to tio2 and cuo nps concentration 0.5 wt. %, 0.8 wt.%, and 1 wt.% at 40 °c, respectively. increasing the viscosity of light base oil 40 stock after adding nanomaterials figure (8) shows the viscosity index changes with adding modified tio2cuo nps. the viscosity index increased by 4.5%, 8.4%, 9.92%, and 7.7% relative to the different nps concentrations at 0.2 wt.%, 0.5 wt.%, 0.8 wt.%, and 1 wt.%, respectively. the maximum increase was observed at 8 wt. % concentration. the higher viscosity index indicates a more stable kinematic viscosity with variable temperatures, thus giving more resistance to oil film thinning [32]. (a) (b) fig. 7. effect of tio₂cuo on the kinematic viscosity of base oil 40 stock at (a) 40 °c, and at (b) 100°c m. r.fahad and b. a. abdulmajeed / iraqi journal of chemical and petroleum engineering 23,1 (2022) 1 7 5 fig. 8. effect of tio₂cuo nps on the viscosity index of base oil 40 stock 3.4. flashpoint and pour point of nano-lubricating oil the flashpoint (f.p) can be defined as the less temperature that a flammable mixture in the air can be formed. in an instant, the oil follows the ignition line and then suddenly switches off. fig. 9 and fig. 10 demonstrate the effect of modified tio2 – cuo nps on the flashpoint and pour point property of base oil 40 stock, respectively. it can be seen that the flashpoint increased with adding the nps to base oil 40 stock attributed to the high thermal conductivity of nanoparticles, and it can be said that it allows the oil to resist ignition better [33]. the rate of improvement in f.p is 14 °c at 0.2 wt% concentration of nps and the greater improvement was 32 ̊c at 1 wt.% concentration. while the pour point of base oil improved by 3 °c at 0.2 wt.%, 0.5 wt%, and 0.8 wt.% compared with base oil. the higher improvement was at 1wt % by 6 °c. fig. 9. effect of nano additive modified tio₂-cuo wt. % on flash point of base oil 40 stocks fig. 10. effect of nano additive modified tio₂-cuo wt. % on pour point of base oil 40 stocks 4conclusions  using oleic acid surfactant in surface modification of tio₂, and cuo nps improved the stability of lubricating oil  the kinematic viscosity of modified tio2-cuo / base oil 40 stock at 40°c and 100 °c increased slightly with the addition of modified nanoparticles.  the viscosity index increased by 4.5% for 40 stock base oil when 0.2% of modified tio₂cuo nanolubricating oil was used. and the highest increase in vi was 9.92 % at 0.8 wt.% of modified tio₂-cuo.  adding tio₂ cuo nps to base oil 40 at varying concentrations improved nano-lubricant oil's flash point compared to parent oil. the highest flash point value was 220 °c references [1] i. mangas, m. a. sogorb, and e. vilanova, lubricating oils, third edit., vol. 3. elsevier, 2014. [2] h. leffmann, the petroleum handbook, vol. 189, no. 1. 1920. [3] m. esso, lubrication in practice. london, uk: the macmillan press limited, 1972. [4] w. dresel, lubricants and lubrication, 2nd ed. ludwigshafen, grmany: deutsche nationalbibliothek, 2007. [5] a. çelik et al., lubricant blending and quality assurance, vol. 1, no. 1. 2018. [6] s. hisham et al., “hybrid nanocellulose-copper (ii) oxide as engine oil additives for tribological behaviour improvement,” molecules, vol. 25, no. 13, 2020, doi: 10.3390/molecules25132975. [7] deepika, “nanotechnology implications for high performance lubricants,” sn appl. sci., vol. 2, no. 6, 2020, doi: 10.1007/s42452-020-2916-8. [8] f. ilie and c. covaliu, “tribological properties of the lubricant containing titanium dioxide nanoparticles as an additive,” lubricants, vol. 4, no. 2, pp. 12–14, 2016, doi: 10.3390/lubricants4020012. [9] m. i. h. c. abdullah et al., “improving engine oil properties by dispersion of hbn/al2o3 nanoparticles,” appl. mech. mater., vol. 607, pp. 70– 73, 2014, doi: 10.4028/www.scientific.net/amm.607.70. [10] n. f. azman and s. samion, “dispersion stability and lubrication mechanism of nanolubricants: a review,” int. j. precis. eng. manuf. green technol., vol. 6, no. 2, pp. 393–414, 2019, doi: 10.1007/s40684-019-00080-x. [11] s. b. mousavi, s. z. heris, and p. estellé, “experimental comparison between zno and mos2 nanoparticles as additives on performance of diesel oil-based nano lubricant,” sci. rep., vol. 10, no. 1, pp. 1–17, 2020, doi: 10.1038/s41598-020-62830-1. [12] w. y. p. das, sarit k, stephen u. s. choi, nanofluid science and technology. canada: a john wiley & sons, inc, 2008. https://books.google.iq/books?hl=en&lr=&id=rykpldzz_aoc&oi=fnd&pg=pr5&dq=%5b4%5d%09w.+dresel,+lubricants+and+lubrication,+2nd+ed.+ludwigshafen,+grmany:+deutsche+nationalbibliothek,+2007.&ots=cloac__yvk&sig=snfvyekvzl3uig1hq_yg8mf5qnq&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=rykpldzz_aoc&oi=fnd&pg=pr5&dq=%5b4%5d%09w.+dresel,+lubricants+and+lubrication,+2nd+ed.+ludwigshafen,+grmany:+deutsche+nationalbibliothek,+2007.&ots=cloac__yvk&sig=snfvyekvzl3uig1hq_yg8mf5qnq&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=rykpldzz_aoc&oi=fnd&pg=pr5&dq=%5b4%5d%09w.+dresel,+lubricants+and+lubrication,+2nd+ed.+ludwigshafen,+grmany:+deutsche+nationalbibliothek,+2007.&ots=cloac__yvk&sig=snfvyekvzl3uig1hq_yg8mf5qnq&redir_esc=y#v=onepage&q&f=false https://www.mdpi.com/1420-3049/25/13/2975 https://www.mdpi.com/1420-3049/25/13/2975 https://www.mdpi.com/1420-3049/25/13/2975 https://www.mdpi.com/1420-3049/25/13/2975 https://www.mdpi.com/2075-4442/4/2/12 https://www.mdpi.com/2075-4442/4/2/12 https://www.mdpi.com/2075-4442/4/2/12 https://www.mdpi.com/2075-4442/4/2/12 https://www.scientific.net/amm.607.70 https://www.scientific.net/amm.607.70 https://www.scientific.net/amm.607.70 https://www.scientific.net/amm.607.70 https://www.scientific.net/amm.607.70 https://link.springer.com/article/10.1007/s40684-019-00080-x https://link.springer.com/article/10.1007/s40684-019-00080-x https://link.springer.com/article/10.1007/s40684-019-00080-x https://link.springer.com/article/10.1007/s40684-019-00080-x https://link.springer.com/article/10.1007/s40684-019-00080-x https://www.nature.com/articles/s41598-020-62830-1 https://www.nature.com/articles/s41598-020-62830-1 https://www.nature.com/articles/s41598-020-62830-1 https://www.nature.com/articles/s41598-020-62830-1 https://www.nature.com/articles/s41598-020-62830-1 https://books.google.iq/books?hl=en&lr=&id=qpbopmspxpyc&oi=fnd&pg=pr7&dq=nanofluid+science+and+technology.&ots=fma3jh-9ys&sig=elqphokdnhslwiuhxcjpskx9yq8&redir_esc=y#v=onepage&q=nanofluid%20science%20and%20technology.&f=false https://books.google.iq/books?hl=en&lr=&id=qpbopmspxpyc&oi=fnd&pg=pr7&dq=nanofluid+science+and+technology.&ots=fma3jh-9ys&sig=elqphokdnhslwiuhxcjpskx9yq8&redir_esc=y#v=onepage&q=nanofluid%20science%20and%20technology.&f=false https://books.google.iq/books?hl=en&lr=&id=qpbopmspxpyc&oi=fnd&pg=pr7&dq=nanofluid+science+and+technology.&ots=fma3jh-9ys&sig=elqphokdnhslwiuhxcjpskx9yq8&redir_esc=y#v=onepage&q=nanofluid%20science%20and%20technology.&f=false m. r.fahad and b. a. abdulmajeed / iraqi journal of chemical and petroleum engineering 23,1 (2022) 1 7 6 [13] x. q. wang and a. s. mujumdar, “a review on nanofluids part ii: experiments and applications,” brazilian j. chem. eng., vol. 25, no. 4, pp. 631–648, 2008, doi: 10.1590/s0104-66322008000400002. [14] v. s.korada, & n. h. b.hamid, engineering applications of nanotechnology, no. april. 2017. [15] a. r. i. ali and b. salam, “a review on nanofluid: preparation, stability, thermophysical properties, heat transfer characteristics and application,” sn appl. sci., vol. 2, no. 10, 2020, doi: 10.1007/s42452-020-03427-1. [16] t. shah, h. koten, and h. ali, “performance effecting parameters of hybrid nanofluids,” in hybrid nanofluids for convection heat transfer, istanbul, turkey: inc, 2020, pp. 179–213. [17] h. m. ali, ed., hybrid nanofluids for convection heat transfer, 1st ed. dhahran: elsevier, academic press, 2020. [18] z. li and y. zhu, “surface-modification of sio2 nanoparticles with oleic acid,” appl. surf. sci., pp. 315–320, 2003. [19] m. kumar, a. afzal, and m. k. ramis, “investigation of physicochemical and tribological properties of tio2 nano-lubricant oil of different concentrations,” tribologia, vol. 35, no. 3, pp. 6–15, 2017. [20] n. baek, y. t. kim, j. e. marcy, s. e. duncan, and s. f. o’keefe, “physical properties of nanocomposite polylactic acid films prepared with oleic acid modified titanium dioxide,” food packag. shelf life, vol. 17, no. may, pp. 30–38, 2018, doi: 10.1016/j.fpsl.2018.05.004. [21] sigma-aldrich, “ir spectrum table,” sigmaaldrich. p. 1, 2019, retrieved from https://www.sigmaaldrich.com/technicaldocuments/articles/biology/ir-spectrum-table.html#irtable-by-compound%0a. [22] y. zhen lv, c. li, q. sun, m. huang, c. rong li, and b. qi, “effect of dispersion method on stability and dielectric strength of transformer oil-based tio2 nanofluids,” nanoscale res. lett., vol. 11, no. 1, pp. 4–9, 2016, doi: 10.1186/s11671-016-1738-5. [23] f. parvizian, f. ansari, and s. bandehali, “oleic acid-functionalized tio 2 nanoparticles for fabrication of pes-based nanofiltration membranes,” chemical engineering research and design vol. 6, pp. 433–441, 2020. [24] a. el-trass, h. elshamy, i. el-mehasseb, and m. el-kemary, “cuo nanoparticles: synthesis, characterization, optical properties and interaction with amino acids,” appl. surf. sci., vol. 258, no. 7, pp. 2997–3001, 2012, doi: 10.1016/j.apsusc.2011.11.025. [25] s. ashokan, v. ponnuswamy, p. jayamurugan, and y. v. s. rao, “fabrication and characterization of cuo nanoparticles : its humidity sensor application,” vol. 1, no. 1, pp. 11–23, 2015. [26] y. gao, g. chen, y. oli, z. zhang, and q. xue, “study on tribological properties of oleic acidmodified tio2 nanoparticle in water,” wear, vol. 252, no. 5–6, pp. 454–458, 2002, doi: 10.1016/s00431648(01)00891-2. [27] k. gu, b. chen, and y. chen, “preparation and tribological properties of lanthanum-doped tio2 nanoparticles in rapeseed oil,” j. rare earths, vol. 31, no. 6, pp. 589–594, 2013, doi: 10.1016/s10020721(12)60325-1. [28] m. jafarpour, m. ghahramaninezhad, and a. rezaeifard, “synthesis, characterization and catalytic activity of oleic acid-coated tio2 nanoparticles carrying moo2 (acac)2 in the oxidation of olefins and sulfides using economical peroxides,” new j. chem., vol. 38, no. 7, pp. 2917–2926, 2014, doi: 10.1039/c4nj00267a. [29] x. song, s. zheng, j. zhang, w. li, q. chen, and b. cao, “synthesis of monodispersed znal 2o 4 nanoparticles and their tribology properties as lubricant additives,” mater. res. bull., vol. 47, no. 12, pp. 4305–4310, 2012, doi: 10.1016/j.materresbull.2012.09.013. [30] c. p. koshy, p. k. rajendrakumar, and m. v. thottackkad, evaluation of the tribological and thermo-physical properties of coconut oil added with mos2 nanoparticles at elevated temperatures, vol. 330–331. elsevier, 2015. [31] m. r. fahad and b. a. abdulmajeed, “experimental investigation of base oil properties containing modified tio2/cuo nanoparticles additives,” j. phys. conf. ser., vol. 1973, no. 1, pp. 0– 12, 2021, doi: 10.1088/1742-6596/1973/1/012089. [32] m. k. a. ali, h. xianjun, l. mai, c. qingping, r. f. turkson, and c. bicheng, “improving the tribological characteristics of piston ring assembly in automotive engines using al2o3 and tio2 nanomaterials as nano-lubricant additives,” tribol. int., vol. 103, pp. 540–554, 2016, doi: 10.1016/j.triboint.2016.08.011. [33] c. pownraj and a. valan arasu, effect of dispersing single and hybrid nanoparticles on tribological, thermo-physical, and stability characteristics of lubricants: a review, vol. 143, no. 2. springer international publishing, 2021. https://link.springer.com/book/10.1007/978-3-319-29761-3?noaccess=true https://link.springer.com/book/10.1007/978-3-319-29761-3?noaccess=true https://link.springer.com/article/10.1007/s42452-020-03427-1 https://link.springer.com/article/10.1007/s42452-020-03427-1 https://link.springer.com/article/10.1007/s42452-020-03427-1 https://link.springer.com/article/10.1007/s42452-020-03427-1 https://link.springer.com/article/10.1007/s42452-020-03427-1 https://www.sciencedirect.com/science/article/pii/b9780128192801000057 https://www.sciencedirect.com/science/article/pii/b9780128192801000057 https://www.sciencedirect.com/science/article/pii/b9780128192801000057 https://www.sciencedirect.com/science/article/pii/b9780128192801000057 https://books.google.iq/books?hl=en&lr=&id=uwxrdwaaqbaj&oi=fnd&pg=pp1&dq=%5b17%5d%09h.+m.+ali,+ed.,+hybrid+nanofluids+for+convection+heat+transfer,+1st+ed.+dhahran:+elsevier,+academic+press,+2020.&ots=wcpqjd90t0&sig=9bsw6ag0eqlfgkgilxl6hrii1q8&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=uwxrdwaaqbaj&oi=fnd&pg=pp1&dq=%5b17%5d%09h.+m.+ali,+ed.,+hybrid+nanofluids+for+convection+heat+transfer,+1st+ed.+dhahran:+elsevier,+academic+press,+2020.&ots=wcpqjd90t0&sig=9bsw6ag0eqlfgkgilxl6hrii1q8&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=uwxrdwaaqbaj&oi=fnd&pg=pp1&dq=%5b17%5d%09h.+m.+ali,+ed.,+hybrid+nanofluids+for+convection+heat+transfer,+1st+ed.+dhahran:+elsevier,+academic+press,+2020.&ots=wcpqjd90t0&sig=9bsw6ag0eqlfgkgilxl6hrii1q8&redir_esc=y#v=onepage&q&f=false https://www.sciencedirect.com/science/article/abs/pii/s0169433203002599 https://www.sciencedirect.com/science/article/abs/pii/s0169433203002599 https://www.sciencedirect.com/science/article/abs/pii/s0169433203002599 https://journal.fi/tribologia/article/view/60703 https://journal.fi/tribologia/article/view/60703 https://journal.fi/tribologia/article/view/60703 https://journal.fi/tribologia/article/view/60703 https://journal.fi/tribologia/article/view/60703 https://www.sciencedirect.com/science/article/abs/pii/s2214289417303848 https://www.sciencedirect.com/science/article/abs/pii/s2214289417303848 https://www.sciencedirect.com/science/article/abs/pii/s2214289417303848 https://www.sciencedirect.com/science/article/abs/pii/s2214289417303848 https://www.sciencedirect.com/science/article/abs/pii/s2214289417303848 https://www.sciencedirect.com/science/article/abs/pii/s2214289417303848 sigma-aldrich,%20 sigma-aldrich,%20 sigma-aldrich,%20 sigma-aldrich,%20 sigma-aldrich,%20 https://link.springer.com/article/10.1186/s11671-016-1738-5 https://link.springer.com/article/10.1186/s11671-016-1738-5 https://link.springer.com/article/10.1186/s11671-016-1738-5 https://link.springer.com/article/10.1186/s11671-016-1738-5 https://link.springer.com/article/10.1186/s11671-016-1738-5 https://www.sciencedirect.com/science/article/abs/pii/s0263876220300800 https://www.sciencedirect.com/science/article/abs/pii/s0263876220300800 https://www.sciencedirect.com/science/article/abs/pii/s0263876220300800 https://www.sciencedirect.com/science/article/abs/pii/s0263876220300800 https://www.sciencedirect.com/science/article/abs/pii/s0263876220300800 https://www.sciencedirect.com/science/article/abs/pii/s0169433211017764 https://www.sciencedirect.com/science/article/abs/pii/s0169433211017764 https://www.sciencedirect.com/science/article/abs/pii/s0169433211017764 https://www.sciencedirect.com/science/article/abs/pii/s0169433211017764 https://www.sciencedirect.com/science/article/abs/pii/s0169433211017764 http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.695.3315&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.695.3315&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.695.3315&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.695.3315&rep=rep1&type=pdf https://www.sciencedirect.com/science/article/abs/pii/s1002072112603251 https://www.sciencedirect.com/science/article/abs/pii/s1002072112603251 https://www.sciencedirect.com/science/article/abs/pii/s1002072112603251 https://www.sciencedirect.com/science/article/abs/pii/s1002072112603251 https://www.sciencedirect.com/science/article/abs/pii/s1002072112603251 https://pubs.rsc.org/en/content/articlelanding/2014/nj/c4nj00267a/unauth https://pubs.rsc.org/en/content/articlelanding/2014/nj/c4nj00267a/unauth https://pubs.rsc.org/en/content/articlelanding/2014/nj/c4nj00267a/unauth https://pubs.rsc.org/en/content/articlelanding/2014/nj/c4nj00267a/unauth https://pubs.rsc.org/en/content/articlelanding/2014/nj/c4nj00267a/unauth https://pubs.rsc.org/en/content/articlelanding/2014/nj/c4nj00267a/unauth https://pubs.rsc.org/en/content/articlelanding/2014/nj/c4nj00267a/unauth https://www.sciencedirect.com/science/article/abs/pii/s0025540812006782 https://www.sciencedirect.com/science/article/abs/pii/s0025540812006782 https://www.sciencedirect.com/science/article/abs/pii/s0025540812006782 https://www.sciencedirect.com/science/article/abs/pii/s0025540812006782 https://www.sciencedirect.com/science/article/abs/pii/s0025540812006782 https://www.sciencedirect.com/science/article/abs/pii/s0025540812006782 https://www.sciencedirect.com/science/article/abs/pii/s0043164814004244 https://www.sciencedirect.com/science/article/abs/pii/s0043164814004244 https://www.sciencedirect.com/science/article/abs/pii/s0043164814004244 https://www.sciencedirect.com/science/article/abs/pii/s0043164814004244 https://www.sciencedirect.com/science/article/abs/pii/s0043164814004244 https://iopscience.iop.org/article/10.1088/1742-6596/1973/1/012089/meta https://iopscience.iop.org/article/10.1088/1742-6596/1973/1/012089/meta https://iopscience.iop.org/article/10.1088/1742-6596/1973/1/012089/meta https://iopscience.iop.org/article/10.1088/1742-6596/1973/1/012089/meta https://iopscience.iop.org/article/10.1088/1742-6596/1973/1/012089/meta https://www.sciencedirect.com/science/article/abs/pii/s0301679x16302535 https://www.sciencedirect.com/science/article/abs/pii/s0301679x16302535 https://www.sciencedirect.com/science/article/abs/pii/s0301679x16302535 https://www.sciencedirect.com/science/article/abs/pii/s0301679x16302535 https://www.sciencedirect.com/science/article/abs/pii/s0301679x16302535 https://www.sciencedirect.com/science/article/abs/pii/s0301679x16302535 https://www.sciencedirect.com/science/article/abs/pii/s0301679x16302535 https://link.springer.com/article/10.1007/s10973-020-09837-y https://link.springer.com/article/10.1007/s10973-020-09837-y https://link.springer.com/article/10.1007/s10973-020-09837-y https://link.springer.com/article/10.1007/s10973-020-09837-y https://link.springer.com/article/10.1007/s10973-020-09837-y m. r.fahad and b. a. abdulmajeed / iraqi journal of chemical and petroleum engineering 23,1 (2022) 1 7 7 تأثير الجسيمات النانوية الهجينة المعدلة على خصائص الزيت األساسي بسمة عباس عبد المجيد 2و مصطفى رعد فهد 1 فطي، وزارة النفط، بغداد، العراقمركز البحث والتطوير الن 1 قسم الهندسة الكيمياوية ، جامعة بغداد، بغداد، العراق 2 الخالصة مض األوليك افي هذه الدراسة ، تم استخدام ح التزييتلتحسين الخصائص االنسيابية والترايبولوجية لزيت لتعديل سطح الجسيمات النانوية لتعزيز تشتت واستقرار الموائع النانوية. تم إجراء تعديل السطح للجسيمات ، حيث oaض األوليكامخافض التوتر السطحي بحمع cuo، و tio2 (nps)النانوية غير العضوية ورييه لتحويل األشعة مطيافية ف كارًها للماء. تم استخدام tio2-cuoض األوليك سطح اميمكن أن يجعل ح كان الهدف الرئيسي من .npsلوصف تعديل سطح sem، والمسح المجهري اإللكتروني ftirتحت الحمراء على الخواص 1:1المعدلة مع نسبة وزن tio2-cuo npsهذه الدراسة هو التحقق من تأثير إضافة نقطة االنسكاب ونقطة الوميض من و viاللزوجة مل اللزوجةمعا و الكاينماتيكية الحرارية الفيزيائية مثل اللزوجة نانو. تم الحصول على أن اللزوجة الحركية للزيت التزييت ال( وزيت زيت االساس 40الزيت األساسي العراقي ) المعدلة. tio2-cuo npsدرجة مئوية تزداد بتركيزات عالية من 100درجة مئوية و 40األساسي عند . 108.5المعدلة tio2-cuo npsوزن. كانت ٪ من 0.8عند 40الزيت األساسي viأعلى قيمة لـ المعدلة من الزيت األساسي tio2-cuo npsأظهرت النتائج أن قيمة نقطة الوميض تزداد مع زيادة تركيز بالوزن. أظهرت % 0.8 عندالنانوي التزييتدرجة مئوية. نقطة صب زيت 220، حيث كانت أعلى قيمة 40 درجة مئوية من الزيت 15-درجة مئوية إلى 12-المعدلة تناقًصا من tio2-cuo npsلنسبة المئوية من ا 40األساسي ، معامل اللزوجة، نقطة الوميضالجسيمات النانويةالتزييت النانوي، زيت ، 40 االساس الزيت الكلمات الدالة: available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.23 no.3 (september 2022) 17 – 24 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: ahmed habib shallal , email: ahmed.alfahd79@gmail.com, name: ibtehal kareem shakir, email: ibtehal.kareem@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. investigating the performance of rechargeable zinc-air fuel cell ahmed habib shallal and ibtehal kareem shakir chemical engineering department, college of engineering, university of baghdad, baghdad, iraq abstract zinc-air fuel cells (zafcs) are a promising energy source that could compete with lithium-ion batteries and perhaps protonexchange membrane fuel cells (pemfcs) for next-generation electrified transportation and energy storage applications. in the present work, a flow-type zafc with mechanical rechargeable was adopted, combined with an auxiliary cell (electrolyzer) for zinc renewal and electrolyte recharge to the main cell. in this work a practical study was performed to calculate the cell capacity (ah), as well as study the electrolysis cell efficiency by current efficiency, and study the effective parameters that have an influence on cell performance such as space velocity and current density. the best parameters were selected to obtain the best performance for cell operation. the obtained cell capacity was 2.4ah. the best performance of the electrolyzer was obtained with 0.6min -1 space velocity. at the same time, the best performance of the electrolyzer was when the value of the current density was 200a/m 2 keywords: fuel cell, zinc-air fuel cell. received on 20/03/2022, accepted on 06/06/2022, published on 30/09/2022 https://doi.org/10.31699/ijcpe.2022.3.3 1introduction zinc air fuel cell (zafc) could be a promising alternative energy source for secondary batteries, proton exchange membrane fuel cell (pemfc), or direct methanol fuel cell (dmfc) due to its high specific energy, low cost of zinc metal and air fuels, and environmentally friendly by-products [1,2]. furthermore, it may employ low-cost metal oxides as catalysts and avoids the problems of storing and compressing explosive or volatile fuels.[3] the zafc is based on simple chemistry, with zinc (zn) serving as a fuel and ambient air serving as an oxidant, respectively, and an aqueous alkaline solution serving as an electrolyte[4,5]. zinc is converted to a zn 2+ cation after losing electrons to an anode current collector[6]. the electrons created on the anode go through an external circuit to an air cathode, where oxygen is reduced and hydroxyl ions (oh ) are formed. the hydroxyl ions migrate through the electrolyte to the anode side, where they react with zinc cations to generate zinc oxides. the following is a summary of the chemical reactions that occur in a zinc air system [7]. anode reactions: zn + 4oh ↔ zn (oh) 4 2 + 2e (e0 = -1.25v) (1) zn(oh)4 2↔ zno + 2 oh + h2o (2) cathode reactions: 1 2 o2 + h2o + 2e ↔ 2oh (e0 = 0.4v) (3) therefore, the overall reaction can be expresses as: 2zn + o2↔ 2zno (e0 = 1.65v) (4) a zinc-air fuel cell (zafc) can be recharged in two ways, mechanical and electrical recharge [8]. an electrically rechargeable zn-air cell is recharged by supplying electricity directly to the cell [9]. during recharge, oxygen is generated at the air electrode whilst zn metal is electrochemically regenerated at the zn electrode. the production of dendritic zn during recharge is a key issue with the zn electrode. this is a severe problem in the zn electrode because it causes direct contact between the cathode and the anode, stopping the cell. moreover, it is hard to find necessary bifunctional catalysts for air cathode to support both oxygen reduction reaction (orr) and oxygen evolution reaction (oer). furthermore, during recharging, the cathode rapidly deteriorates due to the development of oxygen bubbles and air electrode corrosion [10,11]. there are two basic types of mechanically rechargeable zinc-air fuel cells (zafcs): (1) zafcs that can be refueled. (2) reconstructable zafcs. after the discharge process, the zn plates are replaced with new ones in the reconstructable type. in refuelable types, a flowing electrolyte system is used to regenerate or precipitate zinc particles through a co-cell (electrolyzer) and is returned to the main cell again as well as regeneration of the electrolyte [12]. in a zafc, the anode type (fuel) is a major component, and instead of zn plates, zn particles can be used as a fuel source in a flow mode. in recent decades, porous zn plates have been used commercially as anodes for zafcs. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:ahmed.alfahd79@gmail.com mailto:ibtehal.kareem@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2022.3.3 a. h. shallal and i. k. shakir / iraqi journal of chemical and petroleum engineering 23,3 (2022) 17 24 18 the porous structure has a high active surface ratio, which improves reaction efficiency by increasing electrolyte molecule encounters [13]. the zn particles have a greater surface area than a zn plate, allowing for improved contact between the active metal and the electrolyte [14]. as a result, compared to zn plates, zn particles have the following advantages: (i) zn particles have a larger surface area for reaction, which is desired; (ii) the particle anode with flowing electrolyte is very important because it may prevent the hydrogen evolution process (her) and so improve cell performance and power output [15].to keep the electrochemical processes running and create electricity, fuel cells require a constant supply of fuel. the wasted zn anodes will be removed using a circulating flow type electrolyte system, while zn fuel may be delivered to the reaction tank on a regular basis. as a result, without mechanical exchange, the reactant discharge can still be successfully re-supplied [1]. the rechargeable system of zinc-air fuel cell contains two separate electro-chemical systems, the first subsystem is zinc-air fuel cell conventional electricity generation system. the second subsystem is a zinc regeneration electrolytic cell or electrodeposition cell as shown in fig. 1 [16]. fig. 1. schematic view of zinc electrodeposition [16]. zinc can be re-generated by several methods. however, electrolysis or electrodeposition are the best procedures to utilize with zn-air flow cells. the discharge products of the zinc-air fuel cell could be utilized directly in the electrolysis cell or electrolyzer as a reactant. an electrolyzer regenerates zinc from the discharge stream of zn-air flow cells that contain zincate and zinc oxide. the fuel cell is then re-charged with the regenerated zinc [11]. the charging current is provided to the zinc electrolysis cell (electrolyzer) incitement the inverse reactions of zafc. at the negative electrode of the electrolysis cell, as shown in equations (5),(6) zinc is regenerated from the zincate solution resulting from the electrochemical processes that occurred during the discharge in the zincair fuel cell, whereas oxygen (o2) will be formed at the positive electrode (anode) as shown in equation (7) [10]. the following are general electrolysis reactions: at the cathode (negative electrode): zno + 2 oh + h2o↔ zn(oh)4 2 (5) zn (oh)4 2 + 2e ↔zn + 4oh (6) at the anode (positive electrode): 2oh ↔ 1 2 o2 + h2o + 2e (7) general reaction zno ↔ zn+ 1 2 o2 (8) in this work, the zafc of a mechanical refuelling flow type was adopted, combined with a co-cell or electrolyzer for zinc regeneration and electrolyte recharge to the main cell. the operational conditions for zinc-air fuel cells were by choosing the best parameters obtained from our previous study, 40%wt. electrolyte concentration of koh, 6 l/min airflow rate, 100 ml/min electrolyte circulation rate and 50°c electrolyte temperature [17]. a practical study was performed to study the electrolysis cell efficiency, and study some parameters that have an influence on cell performance such as space velocity and current intensity, the best parameters were selected to obtain the best performance for cell operation. after selecting the best parameters that improved the cell's performance, it is necessary to know the amount of energy produced by the cell. 2experimental section 2.1. system design the configuration of a single zinc-air fuel cell (zafc) is shown in fig. 2, it consists of three plates of perspex material as the mainframe because displays efficient chemical resistance against the corrosive electrolyte and oxidation and also facilitates frequent disassembling. apertures were made on the back and front ends of the cell structure, respectively, and are used as electrolyte and air inlet and exhaust gates. each perspex plate had the following dimensions: 15*15*1cm (length, breadth, and thickness). a. h. shallal and i. k. shakir / iraqi journal of chemical and petroleum engineering 23,3 (2022) 17 24 19 fig. 2. photograph of the zinc-air fuel cell (a) left side, (b) right side. one of these plates opened from the inside with a size of (10*10 cm) to be electrolyte storage. the area (active area) of the air cathode was (100 cm 2 ), which was fixed to the left side of the perspex plate. a non-woven fabric separator is placed between the anode and cathode to purpose as a separator to separate the cathode and anode. the air electrode was fixed to the left plate by an epoxy resin material. however, a rubber gasket has been positioned between the acrylic plates to prevent the electrolyte from leakage. seven bolts secure all sides of the perspex plates, holding the cell together. 100 g zinc particles with a diameter of about 0.5mm were placed within a 100-mesh stainless steel pouch that functioned as a current collector for the zn anode. the current collector has a 100 cm 2 surface area. fig. 3. photograph of the air cathode plate fixed to the perspex plates the electrolyte is potassium hydroxide (koh). it was prepared (electrolyte concentration of 40%wt.) by dissolving potassium hydroxide (powder) in distilled water with continuous stirring for (5) minutes. the cathode (air cathode) plate as shown in fig. 3 contained three layers: a catalyst layer, a gas diffusion layer and cathode current collector. 100-mesh stainless steel was working as a current collector of the cathode. a slurry combination of 7 g carbon black and 7 g polytetrafluoroethylene (ptfe) was cast in binder dissolved solvent to create the gas diffusion layer. the solvent was prepared by dissolving 3 g poly-styrene cobutadiene as a binder in 50 ml toluene and leaving it to dissolve completely for 24 hours. the slurry mixture coated mesh stainless steel was then heat-pressed at 110 ◦c for 15min using a manual press tool (employing two steel layers as a press means) in an oven. on the other side of the mesh stainless steel, the catalyst layer was created by dissolving 3 g mno2 and 7 g carbon black in the binder dissolved solvent. the solvent was prepared by dissolving 3 g poly styrene-co-butadiene as a binder in 50ml toluene and leaving it to dissolve completely for 24 hours. the catalyst layered cathode was heat-pressed at 110 º c for 15min using a manual press tool in an oven. the body structure of the electrolyzer is similar to a zinc-air fuel cell in the design. as shown in fig.4 it consists of 4 plates of perspex plate with dimensions 15*15*1cm for each perspex plate, 2 of these plates opened from the inside with a size of (10*10 cm) to be electrolyte storage. also, apertures were formed on one side of the cell, these apertures are considered as gates to inlet spent electrolyte and outlet the fresh electrolyte. the electrolyzer included a stack arrangement with a cathode plate, and anode. the anode plate is made from stainless steel 100-mesh (0.149 mm) with an active area of 100 cm2. the cathode was made of a zinc plate with an area of 100 cm 2 . seven bolts secure all sides of the perspex plates, holding the cell together. the zinc-air fuel cell (zafc) is integrated with the electrolyzer as a complete system as a rechargeable zinc-air fuel cell (zafc). a regenerative fuel cell system requires on-site zinc fuel regeneration following the discharge cycle, which sets it apart from other systems that do not. fig. 4. photograph of the zinc regeneration electrolytic cell (electrolyzer) a. h. shallal and i. k. shakir / iraqi journal of chemical and petroleum engineering 23,3 (2022) 17 24 20 as shown in fig.5, mechanically rechargeable zinc-air fuel cell this system contains a zinc-air fuel cell that is hydraulically connected to the zinc regeneration cell. where the spent electrolyte comes out of the fuel cell and enters the regeneration cell. the electrolyzer precipitates zinc and reactivates the spent electrolyte. the fresh electrolyte leaves the regeneration cell and again it enters the zinc-air fuel cell to continue the cell's reactions and the transfer of electrons, thus generating electricity. a pump circulates the electrolyte between the cell and the additional electrolytic cell (electrolyzer), while flow meters monitor and control the flow. fig. 5. schematic diagram of zinc-air fuel cell combined with zinc electrolysis cell (electrolyzer) air compressor was used to provide the cell with air. airflow meters were used to monitor and control the air entering the cell. the system is also equipped with two digital multimeters, one of which is connected to the zincair fuel cell electrodes to monitoring and record the voltage readings of the cell, and the second is connected between the load and one of the cell electrodes to monitor and record the current. the system is also equipped with a dc power supply to supply the electrolysis cell with the energy needed to regenerate zinc and electrolyte. 2.2. testing methods a. fuel cell capacity measurement the purpose of this test is to check the capacity of the zinc-air fuel cell to produce power. the capacity of the battery is defined as the ability of the battery to store electrical energy, or it can be defined as the amount of electric current that the battery can deliver in a certain period of time, and it is expressed in units of ampere hours (ah), for example, a battery with a 2ah theoretically gives a current of 1 ampere for 2 hours or a current of 2 amperes for one hour. battery capacity can also be defined as the amount of electricity a battery gives off until its voltage drops rapidly. the operational conditions for this experiment were by choosing the best parameters obtained from our previous study [17], 40%wt. electrolyte concentration of koh, 6 l/min airflow rate, 150 ml/min electrolyte circulation rate and the electrolyte temperature at 26°c. the method of the test was by connecting the cell electrodes to the battery tester. the test device contains a constant load (electrical resistance) with a value of 5ω, after adjusting the minimum voltage then pressing the "ok " button to start testing, the device automatically discharges the cell and after the test is started, the tester will display on the device screen the cell data, current, voltage, and fuel cell capacity, ampere-hours (ah), until it reaches the minimum set voltage. after reaching the minimum voltage of the cell, the cell discharge will stop and the capacity of the cell will appear on the screen in units of (ah), which now displays the actual capacity of the zinc-air fuel cell is discharging capacity. b. the space velocity effect on current efficiency for zinc regeneration one of these parameters that are expected to have an impact on the performance of the zinc electrolysis cell (electrolyzer) is the space velocity. in chemical engineering, space velocity is defined as the ratio of the reactant's entering volumetric flow rate to the reactor volume, which shows how many reactor volumes of feed may be handled in a given length of time. the space velocity of the electrolyte inside the electrolysis cell was examined. six different electrolyte flow rates (0, 0.2, 0.4, 0.6, 0.8 and 1 min -1 ) were tested to study their effect on current efficiency (ce) for zinc regeneration. at each flow rate, the cell will be discharged for two hours and then charged for one hour using a charging current of 500ma. the weight of the plate was measured before discharge a zinc plate was used as the anode in the zincair fuel cell. the plate was measured again to determine the amount of reactive or dissolved zinc inside the electrolyte. a laboratory digital dc power supply was used to supply the electrolysis cell with the necessary current. operational conditions for this experiment where the operating temperature was at room temperature, electrolyte concentration 40%wt. of koh. the current efficiency was calculated by the equation (9) [8]: current efficiency of electrolyzer = 𝑛𝐹(𝑁𝑍𝑛,𝑓 − 𝑁𝑍𝑛,0) 𝑖cell 𝐴𝑒𝑙𝑒𝑐.𝑍𝑛 𝑡𝑓 (9) where: n is zinc valence which is 2, f is faraday constant (96،485.3365 c/mol.), 𝑡𝑓 is the total operating time in s, nzn,0 is initial mole of zn and nzn,f is final mole of zn, 𝑖 cell current density, a/cm 2 , a elec. zn is active surface area of zn electrode, cm 2 . space velocity can be expressed mathematically by the equation (10) [18]: space velocity (sv) = v0 v (10) where: vo represents the volumetric flow rate of the electrolyte entering the electrolyzer and v represents the volume of the electrolyzer. a. h. shallal and i. k. shakir / iraqi journal of chemical and petroleum engineering 23,3 (2022) 17 24 21 c. effect of the current density on current efficiency for zinc regeneration the current density (cd) has a significant impact on the performance of the electrolysis cell, so it is necessary to study this parameter and study the best conditions that give the best performance of the cell. in this experiment, seven different values of current density (50, 100, 150, 200, 250, 300 and 350 a/m 2 ) were studied and examined the effect of each value on the current efficiency. the cell was discharged for two hours and then charged for one hour according to the charge current density. the operation conditions for this experiment were (t=28°c) at room temperature, the electrolyte concentration was 40%wt. of koh and the space velocity 0.6 min -1 . a zinc plate electrode was used in the zinc-air fuel cell during discharge; it is weighed before and after the discharge to know the amount of zinc decomposed. in the regeneration cell, a zinc plate was used as the negative electrode and a stainless-steel mesh as the positive electrode. a laboratory digital dc power supply was used to supply the electrolysis cell with the necessary current. 3results and discussions a. zinc-air fuel cell capacity measurement a battery tester device was used to automatically discharge the cell; the fuel cell was operated at room temperature (26 °c), and 40% wt. koh concentration, 6 l/min airflow rate and 150 ml/min electrolyte circulation rate. the cell examination continued for 26 hours. the cell voltage reading was taken every hour and the voltage readings were as shown in fig. 6. after the cell reached the minimum voltage set in the device, the examination process was stopped and the device gave a reading of the cell capacity, which was 2.4 ah. fig. 6. output voltage curve of zafc under test device at temperature (26 °c), and 40% wt. koh concentration, 6 l/min airflow rate and 150 ml/min electrolyte circulation rate 3.2. effect of the space velocity on current efficiency for zinc regeneration after examining the parameters that have an impact on the performance of the zinc-air fuel cell, the parameters that have an effect on the performance of the electrolyzer must be examined. one of these parameters that is expected to have an impact on the performance of the electrolyzer is the space velocity. in chemical engineering, space velocity is defined as the ratio of the reactants' entering volumetric flow rate to the reactor volume, which determines how many reactor volumes of feed can be handled in a given length of time. the space velocity of the electrolyte inside the electrolysis cell was examined. six different space velocity values (0, 0.2, 0.4, 0.6, 0.8 and 1 min -1) were tested to examine their effect on the performance of the electrolytic cell by calculating the current efficiency (ce). the operation conditions for this experiment were at room temperature (t=28°c) and the electrolyte concentration 40%wt. of koh. at each value of space velocity, the cell will be discharged for two hours and then charged for one hour using a charging current of 500ma. the test results are shown in fig.7. there was an increase in current efficiency from no flow state (stagnant) to flowing state at 0.2 min -1 velocity; the performance of the electrolyzer with flowing electrolyte was better than that of the electrolyzer with non-flowing electrolyte. fig. 7. space velocity vs. current efficiency the other parameters t=28°c and 40%wt. electrolyte concentration of koh when the space velocity was increased from 0.2 min -1 till 0.6 min -1 the current efficiency increased, after that, continuing to increase the space velocity from 0.6 min -1 to 1 min -1 did not lead to a significant increase in the performance of the electrolyze. electrolyte hydrodynamics helps to increase ion diffusion and gas bubbles removed in electrolyze. the high flow rate was favored because it lowered the thickness of the zincate ion's diffusion layer. as a result, zn reduction was encouraged [8,19]. a. h. shallal and i. k. shakir / iraqi journal of chemical and petroleum engineering 23,3 (2022) 17 24 22 3.3. effect of the current density on current efficiency for the zinc regeneration process the current density is an important parameter that has an impact on the zinc regeneration process. in this experiment, several values of current density were examined to find out its effect on the regeneration efficiency, which was expressed through current efficiency as shown in equation (9). seven different values of current density (50, 100, 150, 200, 250, 300 and 350 a/m 2 ) were tested to examine the changes in current efficiency. the operation conditions for this experiment were at room temperature (t=28°c), the electrolyte concentration was 40%wt. of koh and the space velocity 0.6 min -1 . the cell will be discharged for two hours and then charged for one hour according to the charge current density; the current efficiency was calculated as in equation (9) was used to evaluate the zn electrolyzer performance. fig. 8 shows the significant increase in the current efficiency, when the current density is increased from 50 to 200a/m 2 , the current efficiency increased from 79% to 94.4%. after that, the increase in the current density did not lead to a significant improvement in the efficiency of the current, and the increase became useless, as when the current density was increased from 200 to 350 a/m 2 , the efficiency of the current increased from 94.4 % to 96.1%, this increase is considered relatively slight for the amount of current applied. the internal resistance of the electrolyte leads to a decrease in the density of the current flowing through it and therefore the voltage decreases, this is referred to as the ir drop. these results agreed with [20]. fig. 8. current density vs. current efficiency the other parameters t=28°c and 40%wt. electrolyte concentration of koh, space velocity 0.6 min -1 4conclusions the cell capacity test, as well as the parameters that affect the zinc regeneration process, were studied. the results and conclusions of this study were as follows: 1after testing the capacity of the zinc-air fuel cell by a battery tester, the cell performance was good relatively to the test period of 26 hours, and the cell capacity can be determined by 2.4ah. 2there was an increase in current efficiency from state no flow conditions (stagnant) to flow state. the best performance of the electrolyzer was when the space velocity was 0.6 min -1 . 3when the current density is increased from 50 to 200a/m 2 , the current efficiency increased from 79% to 94.4%. the best performance of the electrolyzer when the current density value was 200a/m 2 . references [1] p. sapkota and h. kim, “zinc-air fuel cell, a potential candidate for alternative energy,” journal of industrial and engineering chemistry, vol. 15, no. 4, pp. 445450, 2009, doi: 10.1016/j.jiec.2009.01.002. [2] f. c. handbook, “fuel fuel cell handbook fuel,” system, pp. 1_3-1_5, 1998. [3] p. t. chen et al., “improved performance of a zn-air fuel cell by coupling zn particle fuel and flowing electrolyte,” chemical physics letters, vol. 728, no. february, pp. 160–166, 2019, doi: 10.1016/j.cplett.2019.04.085. [4] p. sapkota and h. kim, “an experimental study on the performance of a zinc air fuel cell with inexpensive metal oxide catalysts and porous organic polymer separators,” journal of industrial and engineering chemistry, vol. 16, no. 1, pp. 39-44, 2010, doi: 10.1016/j.jiec.2010.01.024. [5] v. neburchilov, h. wang, j. j. martin, and w. qu, “a review on air cathodes for zinc-air fuel cells,” journal of power sources, vol. 195, no. 5, pp. 1271-1291, 2010, doi: 10.1016/j.jpowsour.2009.08.100. [6] t. sangeetha, p. t. chen, w. m. yan, and k. d. huang, “enhancement of air-flow management in znair fuel cells by the optimization of air-flow parameters,” energy, vol. 197, 2020, doi: 10.1016/j.energy.2020.117181. [7] a. l. zhu, d. p. wilkinson, x. zhang, y. xing, a. g. rozhin, and s. a. kulinich, “zinc regeneration in rechargeable zinc-air fuel cells-a review,” journal of energy storage, vol. 8, no. september, pp. 35-50, 2016, doi: 10.1016/j.est.2016.09.007. [8] w. lao-atiman, k. bumroongsil, a. arpornwichanop, p. bumroongsakulsawat, s. olaru, and s. kheawhom, “model-based analysis of an integrated zinc-air flow battery/zinc electrolyzer system,” frontiers in energy research, vol. 7, no. feb, pp. 1–15, 2019, doi: 10.3389/fenrg.2019.00015. [9] x. g. zhang, “secondary batteries – zinc systems contents,” encyclopedia of electrochemical power sources, pp. 454–468, 2009 [10] p. pei, k. wang, and z. ma, “technologies for extending zinc-air battery’s cyclelife: a review,” applied energy, vol. 128, pp. 315–324, 2014, doi: 10.1016/j.apenergy.2014.04.095. https://www.sciencedirect.com/science/article/pii/s1226086x09001324 https://www.sciencedirect.com/science/article/pii/s1226086x09001324 https://www.sciencedirect.com/science/article/pii/s1226086x09001324 https://www.sciencedirect.com/science/article/pii/s1226086x09001324 https://www.sciencedirect.com/science/article/pii/s000926141930380x https://www.sciencedirect.com/science/article/pii/s000926141930380x https://www.sciencedirect.com/science/article/pii/s000926141930380x https://www.sciencedirect.com/science/article/pii/s000926141930380x https://www.sciencedirect.com/science/article/pii/s000926141930380x https://www.sciencedirect.com/science/article/pii/s1226086x10000250 https://www.sciencedirect.com/science/article/pii/s1226086x10000250 https://www.sciencedirect.com/science/article/pii/s1226086x10000250 https://www.sciencedirect.com/science/article/pii/s1226086x10000250 https://www.sciencedirect.com/science/article/pii/s1226086x10000250 https://www.sciencedirect.com/science/article/pii/s1226086x10000250 https://www.sciencedirect.com/science/article/pii/s0360544220302887 https://www.sciencedirect.com/science/article/pii/s0360544220302887 https://www.sciencedirect.com/science/article/pii/s0360544220302887 https://www.sciencedirect.com/science/article/pii/s0360544220302887 https://www.sciencedirect.com/science/article/pii/s0360544220302887 https://www.sciencedirect.com/science/article/pii/s2352152x16301591 https://www.sciencedirect.com/science/article/pii/s2352152x16301591 https://www.sciencedirect.com/science/article/pii/s2352152x16301591 https://www.sciencedirect.com/science/article/pii/s2352152x16301591 https://www.sciencedirect.com/science/article/pii/s2352152x16301591 https://www.frontiersin.org/articles/10.3389/fenrg.2019.00015/full https://www.frontiersin.org/articles/10.3389/fenrg.2019.00015/full https://www.frontiersin.org/articles/10.3389/fenrg.2019.00015/full https://www.frontiersin.org/articles/10.3389/fenrg.2019.00015/full https://www.frontiersin.org/articles/10.3389/fenrg.2019.00015/full https://www.frontiersin.org/articles/10.3389/fenrg.2019.00015/full https://www.sciencedirect.com/science/article/pii/s0306261914004589 https://www.sciencedirect.com/science/article/pii/s0306261914004589 https://www.sciencedirect.com/science/article/pii/s0306261914004589 https://www.sciencedirect.com/science/article/pii/s0306261914004589 a. h. shallal and i. k. shakir / iraqi journal of chemical and petroleum engineering 23,3 (2022) 17 24 23 [11] h. f. wang and q. xu, “materials design for rechargeable metal-air batteries,” matter, vol. 1, no. 3, pp. 565–595, 2019, doi: 10.1016/j.matt.2019.05.008. [12] t. sangeetha, p. t. chen, w. f. cheng, w. m. yan, and k. d. huang, “optimization of the electrolyte parameters and components in zinc particle fuel cells,” energies, vol. 12, no. 6, 2019, doi: 10.3390/en12061090. [13] l. f. arenas, a. loh, d. p. trudgeon, x. li, c. ponce de león, and f. c. walsh, “the characteristics and performance of hybrid redox flow batteries with zinc negative electrodes for energy storage,” renewable and sustainable energy reviews, vol. 90, no. january, pp. 992–1016, 2018, doi: 10.1016/j.rser.2018.03.016. [14] t. sangeetha, c. j. yang, p. t. chen, w. m. yan, and k. d. huang, “discharge performance of zn-air fuel cells under the influence of carbopol 940 thickener,” international journal of energy research, vol. 44, no. 6, pp. 4543–4555, 2020, doi: 10.1002/er.5230. [15] g. li, k. zhang, m. a. mezaal, r. zhang, and l. lei, “effect of electrolyte concentration and depth of discharge for zinc-air fuel cell,” international journal of electrochemical science, vol. 10, no. 8, pp. 6672– 6683, 2015. [16] k. wang, p. pei, z. ma, h. xu, p. li, and x. wang, “morphology control of zinc regeneration for zinc-air fuel cell and battery,” journal of power sources, vol. 271, pp. 65–75, 2014, doi: 10.1016/j.jpowsour.2014.07.182. [17] a. h. shallal and i. k. shakir, “effects of operating parameters on the performance of a zinc-air fuel cell,” journal of physics: conference series, vol. 1973, no. 1, 2021, doi: 10.1088/17426596/1973/1/012122. [18] j. r. couper, w. r. penney, j. r. fair, and s. m. walas, “17 chemical reactors,” pp. 591–653, 2012, [online]. [19] p. pei, z. ma, k. wang, x. wang, m. song, and h. xu, “high performance zinc air fuel cell stack,” journal of power sources, vol. 249, pp. 13–20, 2014, doi: 10.1016/j.jpowsour.2013.10.073. [20] b. sharifi, m. mojtahedi, m. goodarzi, and j. vahdati khaki, “effect of alkaline electrolysis conditions on current efficiency and morphology of zinc powder,” hydrometallurgy, vol. 99, no. 1-2, pp. 72-76, 2009, doi: 10.1016/j.hydromet.2009.07.003. https://www.sciencedirect.com/science/article/pii/s2590238519300335 https://www.sciencedirect.com/science/article/pii/s2590238519300335 https://www.sciencedirect.com/science/article/pii/s2590238519300335 https://www.sciencedirect.com/science/article/pii/s2590238519300335 https://www.mdpi.com/431870 https://www.mdpi.com/431870 https://www.mdpi.com/431870 https://www.mdpi.com/431870 https://www.mdpi.com/431870 https://www.sciencedirect.com/science/article/pii/s1364032118301242 https://www.sciencedirect.com/science/article/pii/s1364032118301242 https://www.sciencedirect.com/science/article/pii/s1364032118301242 https://www.sciencedirect.com/science/article/pii/s1364032118301242 https://www.sciencedirect.com/science/article/pii/s1364032118301242 https://www.sciencedirect.com/science/article/pii/s1364032118301242 https://www.sciencedirect.com/science/article/pii/s1364032118301242 https://onlinelibrary.wiley.com/doi/abs/10.1002/er.5230 https://onlinelibrary.wiley.com/doi/abs/10.1002/er.5230 https://onlinelibrary.wiley.com/doi/abs/10.1002/er.5230 https://onlinelibrary.wiley.com/doi/abs/10.1002/er.5230 https://onlinelibrary.wiley.com/doi/abs/10.1002/er.5230 https://onlinelibrary.wiley.com/doi/abs/10.1002/er.5230 http://www.electrochemsci.org/papers/vol10/100806672.pdf http://www.electrochemsci.org/papers/vol10/100806672.pdf http://www.electrochemsci.org/papers/vol10/100806672.pdf http://www.electrochemsci.org/papers/vol10/100806672.pdf http://www.electrochemsci.org/papers/vol10/100806672.pdf https://www.sciencedirect.com/science/article/pii/s0378775314012385 https://www.sciencedirect.com/science/article/pii/s0378775314012385 https://www.sciencedirect.com/science/article/pii/s0378775314012385 https://www.sciencedirect.com/science/article/pii/s0378775314012385 https://www.sciencedirect.com/science/article/pii/s0378775314012385 https://iopscience.iop.org/article/10.1088/1742-6596/1973/1/012122/meta https://iopscience.iop.org/article/10.1088/1742-6596/1973/1/012122/meta https://iopscience.iop.org/article/10.1088/1742-6596/1973/1/012122/meta https://iopscience.iop.org/article/10.1088/1742-6596/1973/1/012122/meta https://iopscience.iop.org/article/10.1088/1742-6596/1973/1/012122/meta https://www.sciencedirect.com/science/article/pii/s0378775313017394 https://www.sciencedirect.com/science/article/pii/s0378775313017394 https://www.sciencedirect.com/science/article/pii/s0378775313017394 https://www.sciencedirect.com/science/article/pii/s0378775313017394 https://www.sciencedirect.com/science/article/pii/s0304386x09001789 https://www.sciencedirect.com/science/article/pii/s0304386x09001789 https://www.sciencedirect.com/science/article/pii/s0304386x09001789 https://www.sciencedirect.com/science/article/pii/s0304386x09001789 https://www.sciencedirect.com/science/article/pii/s0304386x09001789 a. h. shallal and i. k. shakir / iraqi journal of chemical and petroleum engineering 23,3 (2022) 17 24 24 هواء القابلة العادة الشحن -دراسة كفاءة االداء لخلية وقود الزنك ابتهال كريم شاكر و احمد حبيب قسم الهندسة الكيمياوية -كلية الهندسة -جامعة بغداد الخالصة ( مصدر طاقة واعًدا يمكن أن ينافس بطاريات الليثيوم أيون وربما خاليا وقود غشاء zafcsتعتبر خاليا وقود الزنك والهواء ) من النوع zafc( للجيل التالي من تطبيقات النقل وتخزين الطاقة. في هذا العمل ، تم اعتماد pemfcsتبادل البروتون ) عادة تجديد المتدفق مع إمكانية إعادة الشحن ميكانيكًيا ، باستخدام خلية مشتركة )خلية التحلل الكهربائي( لتجديد الزنك وا ( ، وكذلك دراسة كفاءة ahل تم اجراء دراسة عملية لحساب سعة الخلية )االلكترواليت واعادته إلى الخلية الرئيسية. في هذا العم ( space velocityخلية التحلل الكهربائي من حيث كفائة التيار، ودراسة بعض المتغيرات التي لها تأثير على أداء الخلية مثل ال) ة. كانت سعة الخلية التي تم الحصول عليها وكثافة التيار ، و اختيار افضل العوامل للحصول على أفضل أداء لتشغيل الخلي . أفضل أداء لخلية 1-دقيقة 0.6 (space velocity)ساعة. كان أفضل أداء لخلية التحلل الكهربائي عندما كانت ال -امبير2.4 2امبير/م200التحلل الكهربائي هو عندما تكون قيمة كثافة التيار هواء-الزنكالكلمات الدالة: خاليا الوقود, خاليا وقود iraqi journal of chemical and petroleum engineering vol.13 no.1 (march 2012) 19 issn: 1997-4884 extraction of pelletierine from punica granatum l.by liquid membrane technique and modelling adel a. al-hemiri * , khalid m. abed ** , ayaad w. al-shahwany† * environmental engineering department-college of engineering-university of baghdad-iraq ** chemical engineering department-college of engineering-university of baghdad-iraq † biology department-college of sciences -university of baghdad-iraq abstract this work was conducted to study the extraction of pelletierine sulphate from punica granatum l. roots by liquid membrane techniques. pelletierine sulphate is used widely in medicine. the general behavior of extraction process indicates that pelletierine conversion increased with increasing the number of stages and the discs rotation speed but high rotation speed was not favored because of the increased risk of droplet formation during the operation. the ph of feed and acceptor solution was also important. the results exhibit that the highest pelletierine conversion was obtained when using two stages, (10 rpm) discs speed of stainless steel discs, (ph=9.5) of feed solution and (ph=2) of acceptor solution in n-decane. assuming the existence of two thin reaction layers in the feed and stripping solutions, mathematical model was developed to describe the pelletierine transport. on the basic of the experimental data obtained under various conditions and the model proposed, it was found that the solute transfer into the liquid membrane is mainly diffusion-controlled. keywords: liquid membrane, extraction, pelletierine, punica granatum l., modelling. ةلخالصا لترين سلفيت من جذور نبات الرمان بأستخدام تقنيات السائل ݒيهدف هذا البحث الى دراسة استخالص دواء ال لترين يستخدم بصوره واسعه في الطب ,حيث يستخدم للقضاء على الديدان الشريطيه والديدان ݒالغشائي. ال المعويه وكعالج لالسهال و الدازنتري ,وكمضاد بكتيري. وبينت الدراسات الحديثه بأنه يستعمل كمضاد فطري على نمو فيروس االيدز.عندما يمزج مع االمالح الحديديه , وهذه المجموعه نفسها استعملت الختبار تأثيره لترين يزداد عند زيادة عدد المراحل وسرعة دوران ݒالسلوك العام لعملية االستخالص يشير الى ان تحول ال االقراص لكن السرع العاليه كانت غير مفضله بسبب تكون قطرات على االقراص وبالتالي نقصان بالمساحه للمحلول الداخل والمستلم كانت محكومه ضمن حد معين.السطحيه للطبقات المتجدده. ولكن درجة الحامضيه 01لترين تم الحصول عليه عند استخدام مرحلتين , سرعة دوران األقراص )ݒاظهرت النتائج ان اعلى تحول لل وبأستخدام 2, درجة الحامضيه للمحلول المستلم = 5.9للمحلول الداخل = ةدرجة الحامضي ( وقةدوره / دقي الديكان كسائل غشائي . لترين على افتراض وجود طبقتي تفاعل رقيقه في المحلول ݒلوصف عملية انتقال ال تم تطوير موديل رياضي وذج الرياضي المقترح وجد ان الداخل والمستلم . على اساس البيانات التجريبيه التي تم الحصول عليها والنم انتقال المذيب الى الغشاء السائل مسيطر عليه بشكل اساسي من قبل االنتشار. iraqi journal of chemical and petroleum engineering university of baghdad college of engineering extraction of pelletierine from punica granatum l.by liquid membrane technique and modelling 2 ijcpe vol.13 no.1 (march 2012) -available online at: www.iasj.net introduction pelletierine c8h15no is a liquid alkaloid obtained from the root bark of punica granatum linn. it is anthelmintic and amoeboid. pelletierine triggers, like strychnine, a raised stimulant reflex, which can escalate to tetanus and is effective against diverse tapeworms, ring worms and nematodes [1] . more recent studies showed that the simple extract have efficacy against the virulent intestinal bacteria salmonella typhi [2] and vibrio cholera, and most recently, viruses including herpes simplex [3] and human immunodeficiency virus (hiv) and tumors [4] . because of the structural diversity of alkaloids, there is no single method of their extraction from natural raw materials [5] . most methods exploit the property of most alkaloids to be soluble in organic solvents but not in water, and the opposite tendency of their salts. most plants contain several alkaloids. their mixture is extracted first and then individual alkaloids are separated. plants are thoroughly grounded before extraction. most alkaloids are present in the raw plants in the form of salts of organic acids. liquid membrane extraction was introduced as an alternative separation technique to the liquid-liquid extraction and to the separation by means of solid polymeric membrane. this property of membranes makes them useful in the textile and food industries, in hydrometallurgy, medicine, biotechnology, environmental protection, in the separation of hydrocarbons and gases, and in the concentration and separation of amino acids, metal ions and other mixtures and suspensions [6, 7] . liquid membranes have also been used extensively in the extraction of both organic molecules such as pesticides and herbicides in waters and wastewaters and metals in water and wastewater matrices as well as other organic pollutants [8] . the use of liquid membranes presents an attractive approach to produce valuable products of high quality at reduced costs, giving the opportunity to use as liquid membranes less powerful but more selective, less toxic and less expensive solvents than in the case of classical solvent extraction [9] [10] [11][12] . membrane-based extraction methods have now gained popularity as methods of choice in the extraction of both ionisable and non-ionisable molecules from different samples. the main attractive features for these techniques include the use of minimal organic solvents, high selectivity and clean-up efficiency, with high enrichment factors. in most cases the overall cost involved is low due to the simplicity of the techniques which normally involve relatively fewer steps and handling procedures as compared to many other sample-preparation techniques [8] . a bulk liquid membrane process for recovery of medicinal compounds from dilute ammoniacal leach solutions was used in this work. applying pertraction in a rotating film contactor (rfc) the alkaloid was successfully recovered from model solution of pelletierine, as well as from native aqueous extracts obtained from the punica granatum l. roots. the aim of this work was to study the process of pelletierine recovery from its solution using a liquid membrane technique and to apply this procedure for selective recovery of alkaloids from native aqueous extraction of punica granatum l. roots to produce pelletierine sulphate medicine. adel a. al-hemiri, khalid m. abed, ayaad w. al-shahwany -available online at: www.iasj.net ijcpe vol.13 no.1 (march2012) 3 experimental work reagent and analytical methods used various reagents were used in this work as liquid membrane, n-decane and n-nonane (99% bdh), n-hexane (95% aldrich) and methyl cyclohexane (95% hopkin & williams). ammonia (25% chemsupply) and sulfuric acid (98% gcc) were used to adjust the acidity of the aqueous solutions. the concentration of pelletierine in the strip solution was measured by uvspectrophotometer sp-3000 (optima inc) at wave length λ=254 nm. the ph values of the aqueous solutions were measured by means of the laboratory ph meter (crison, mm40). experimental equipment the studies of pelletierine pertraction were carried out in a laboratory rotating film contactor (rfc) made from perspex (poly methyl methacrylate). the lower part of contactor is divided, as shown in fig.1, into four compartments: two for the feed and two for the acceptor solution. compartments containing the same aqueous solution are interconnected. the organic membrane liquid occupies the common upper part of the contactor. fig.1, experimental apparatus contactor: (1) body of rotating film contactor, (2) stage wall, (3) feed/stripping solution separating walls, (4) rotating disks, and (5) common shaft. four discs, 1 mm thick and 18 cm in diameter, mounted vertically on a common shaft, rotated in each compartment, providing continuous renewal of the aqueous films, covering the discs, as well as the stirring of all three liquids. the lower part of each disc (up to one-third of the disc diameter) is immersed in the corresponding aqueous solution and the larger, upper part is immersed in the organic membrane liquid, as shown in fig.1. the aqueous solutions from mobile liquid films on the corresponding disc surfaces, which contact with the organic membrane .the two stages could be connected in a way permitting co-, counter or batch operation modes. to homogenise the aqueous solutions and to provide samples from each solution, both liquids were re-circulated by means of two peristaltic pumps watson-marlow limited (falmouth cornwall england). for constant shaft rotating in small rpms: dc-motor (50 rpm) and variable dc power supply (smart power system, ema series). for the pertraction studies, the following three-liquid-phase system was used:  feed (donor) solution (f): 250 ml aqueous solution of ammonia, containing 1.13 mmol/liter of pelletierine c8h15no;  membrane solution (m): 500 ml : ndecane, n-nonane, n-hexane and methyl cyclohexane;  stripping solution (s): 250 ml aqueous solution of sulfuric acid. experimental procedure 5.0 grams of punica granatum l. roots were milled to fine powder and leached by 250 ml of buffer solution of (nh3-(nh4)2so4) adjusted to appropriate ph. this solution was shaken for half an hour and filtered to obtain the feed solution. extraction of pelletierine from punica granatum l.by liquid membrane technique and modelling 4 ijcpe vol.13 no.1 (march 2012) -available online at: www.iasj.net the solution from the above step was poured into the rfc using glass funnel, the acceptor solution was adjusted to appropriate ph using few drops of sulfuric acid and placed into the second compartment, and the remainder volume was filled with the liquid membrane. mathematical model overall mass transfer the overall mass transfer under steady-state condition consists of three mass transfer processes: the mass transfer in feed phase, in the membrane phase and in strip phase. this analysis starts with the basic mass transfer equation: j=k (c‒c*) ………….. (1) where j is the mass flux (mole/m 2 .s), k is the mass transfer coefficient (m/s), c and c* is concentration and equilibrium concentration (mole/m 3 ) respectively. assuming a batch process and according to the model accepted, it is assumed that pelletierine is transported from the bulk of feed solution (f) to the reaction zone, representing a thin film of the feed solution adjacent to the f/m interface (fig. 2). in general, the reaction zones are thinner than the diffusional layers [13] . the diffusional flux of pelletierine from the bulk of the donor phase to the organic membrane is given by the expression: j= kfm. (cf-cf*), or j= kfm. (cf-m1cm) ……….….. (2) where kfm is the individual mass transfer coefficient between the feed and membrane solution, cf and cf* are the concentration and equilibrium concentration of the feed solution respectively, m1 is the equilibrium constant and cm is the concentration in the organic membrane. fig.2, mechanism of pelletierine transport across liquid membrane (lm) by analogy the diffusional flux from membrane to the strip solution is given by the expression: j= kms. (cm –cm*), or j= kms. (cm-m2cs) …….….… (3) where kms is the individual mass transfer coefficient between the membrane and stripping solution, m2 is equilibrium constant; cs is the concentration in the stripping solution. the overall diffusional flux from feed to strip solution is given by the following expression: j= kfs. (cf-cs) ….………. (4) rewriting eq. (2) & (3): cm= . …….….. (2)* cm= . c ...….…. (3)* by equating (2)*& (3)* . = . c . c = j ( . ) . c = j ( ) …...….. (5) where kfs is the overall mass transfer coefficient. total resistance to mass transfer = sum of individual resistances; i.e., = ……….……. (6) adel a. al-hemiri, khalid m. abed, ayaad w. al-shahwany -available online at: www.iasj.net ijcpe vol.13 no.1 (march2012) 5 by substituting eq. (2), (3) and (4) in to eq. (6) and rearranging of equation (6) we get: c = c ( ) ……..……. (7) material balance on solute vf c ο f=vf cf +vm cm+vs c….…. (8) where vf, vm and vs are the feed, membrane and striping solution volume; c ο f is the initial concentration of feed solution. by substituting eq. (7), into eq. (8) and rearranging it we get: cf= c ο f c ( ) …… (9) mass balance equations with the stagnant feed and strip phase, the mass balance equation in the feed and strip phase using eq. (5) is: = = kfs. a ( c ) ……………….(10) where a is the interfacial area (represented by the face of the liquid membrane body facing the disc). the equations are subjected to the following initial conditions: cf=c ο f cs=0 …….……..(11) cm=0 at vf=vs=250 ml =250 cm 3 , vm=500 ml =500 cm 3 , a= 160 cm 2 c ο f= 1.13 mmol/liter m1= 300, m2= 0.003 where m1 and m2 is measured experimentally. the mathematical model, based on the rate equation (eq. (10) and (11), mass balance eq. (9) and the earlier mentioned initial conditions describes the batch process of pelletierine pertraction in a rotating film contactor. by substitute the boundary conditions and integrating the general eq. (10) ∫ . = .4 6k ∫ ..... …(12) . . = .4 6 k . … (13) a plot of . . against time (t) gives gradient of (0.416 kfs), from which kfs is calculated. results and discussion selection of organic membrane four organic non-polar solvent were used as liquid membrane. low molecular weight solvents failed to give reasonable extraction efficiency while n-decane (with the highest molecular weight, 142.29) gave a good extracting ability and mass transfer coefficient as shown in table 1and fig. 3. the increase in molecular weight of the organic compounds results in the increase of its organic properties, and since pelletierine is an organic compounds thus its solubility increases with the increase of the molecular weight of the solvent (likes dissolve like). these results are in agreement with the results which were obtained by dimitrov et al [14] . fig. 3,plotting equation (13) showing effect of type of solvent 0 0.5 1 1.5 2 2.5 3 3.5 4 0 50 100 150 time(min) n-decane n-nonane n-hexane m.c.h. extraction of pelletierine from punica granatum l.by liquid membrane technique and modelling 6 ijcpe vol.13 no.1 (march 2012) -available online at: www.iasj.net table 1, values of mass transfer coefficient evaluated from fig. (3), showing the effect of type of solvent no. run kfs value (m/s) 1. n-decane 1.4* 2. n-nonane 2.1* 3. n-hexane 4.0* 4. m.c.h 1.5* effect of ph of feed (donor) solution on the extraction percentage and mass transfer coefficient in order to study the effect of ph in the feed phase(phf) on the mass transfer performance of blm process, ph in the feed phase is adjusted with ammonia buffer solution. experimental studies were carried out at various ph values (7-11). the overall mass transfer coefficient increases with increasing ph; and maximum mass transfer coefficient is observed at ph of 9.5; then it decreases as shown in fig. 4 and table 2. it is to be concluded that the best ph for the feed solution that gave good extraction percentage is around 9.5. such results are in agreement with that obtained by dimitrov et al (2005 and 2006) [15] [16] . fig. 4, plotting equation (13) showing the effect of ph of feed solution table 2, values of mass transfer coefficient evaluated from fig. (4), showing the effect of ph of feed solution no. run kfs value (m/s) 1. phf=7.0 2.8* 2. phf=8.0 4.7* 3. phf=9.0 1.3* 4. phf=9.5 1.4* 5. phf=10 2.8* 6. phf=11 2.8* effect of ph of stripping (acceptor) solution on the extraction percentage and mass transfer coefficient in order to study the effect of ph in the stripping phase(phs) on the mass transfer performance of blm process, ph in the feed phase is adjusted with few drops of sulfuric acid. experimental studies were carried out at various ph values (1.5-3). the overall mass transfer coefficient increases with increasing ph; and maximum mass transfer coefficient is observed at ph of 2; then it decreases as shown in fig. 5 and table 3. fig. 5, plotting equation (13) showing the effect of ph of stripping solution it is observed that the ph of the aqueous acceptor phase played an important role on the extraction of pelletierine values when all the experimental conditions were kept constant except for the ph value of acceptor solution. 0 0.5 1 1.5 2 2.5 3 3.5 4 0 50 100 150 time(min) ph=7 ph=8 ph=9 ph=10 ph=11 ph=9.5 0 1 2 3 4 0 50 100 150 time(min) ph=1.5 ph=2 ph=2.5 pha=3 adel a. al-hemiri, khalid m. abed, ayaad w. al-shahwany -available online at: www.iasj.net ijcpe vol.13 no.1 (march2012) 7 these results are in agreement with dimitrov et al (2005 and 2004) [15, 17] . table 3, values of mass transfer coefficient evaluated from fig. 5, showing the effect of ph of acceptor solution no. run kfs value (m/s) 1. phs=1.5 1.2* 2. phs=2.0 1.4* 3. phs=2.5 3.9* 4. phs=3.0 7.9* effect of discs rotation speed pertraction efficiency grows with the increase of discs rotation speed, due to the better agitation of all three phases and the faster renewal of the aqueous films. the overall mass transfer coefficient increases with increasing discs rotation speed as shown in fig. 6 and table 4. this is similar to the results obtained by dimitrov et al (2002) [13] . fig. 6, plotting equation (13) showing the effect of discs speed on the other hand when higher rotation speed (higher than 10 rpm) is used also gives smaller amount of pelletierine sulphate and small value of mass transfer coefficient. higher rotation speed was not favored because of the increased risk of droplet formation and process deterioration, where these agree with the results obtained by dimitrov et al(2005) [18] and (2008) [14] . table 4, values of mass transfer coefficient evaluated from fig. 6, showing the effect of disk speed no. run kfs value (m/s) 1. 5 rpm 5.0* 2. 10 rpm 1.4* 3. 15 rpm 3.7* effect of number of stages increasing number of stages in rfc design play an important role to increase the yield or extraction efficiency and overall mass transfer coefficient. if two stages are used, this mean four hydrophilic disks that lead to an increase in surface area which will be in contact with the feed solution; therefore, pelletierine exhausting from roots increase and the same increase occurs in membrane. the overall mass transfer coefficient increases with increasing the number of stages as shown in fig. 7 and table 5 [19] . fig. 7, plotting equation (13) showing the effect of number of stages [19] table 5, values of mass transfer coefficient evaluated from fig. (6), showing the effect number of stages [19] no. run kfs value (m/s) 1. one stage 5.0* 2. two stage 1.4* on the other hand increasing the number of stages leads to an increase in surface area which is in contact with the acceptor solution, thus increasing h2so4 molecules in contact with the 0 1 2 3 4 0 50 100 150 time(min) 5 rpm 10 rpm 15 rpm 0 1 2 3 4 0 50 100 150 time(min) one stage two stage extraction of pelletierine from punica granatum l.by liquid membrane technique and modelling 8 ijcpe vol.13 no.1 (march 2012) -available online at: www.iasj.net membrane. these results are in higher conversion than those from one stage. conclusions a bulk liquid membrane technique for simultaneous extraction and stripping process based on surface renewal theory is presented. the pertraction in rotating film contactor is a suitable technique for pelletierine extraction from its solutions. the following results are found from blm pertraction of pelletierine from punica granatum l. roots:  the non-polar n-decane was found to be the most suitable for pelletierine recovery by pertraction process.  the best stripper (accepter) solution was h2so4 with ph=2.  the best ph value of feed (donor) solution was ph=9.5  three speeds were used, viz, 5, 10 and 15 rpm. the best speed was 10 rpm where high rotation speed was not favored because of the increased risk of droplet formation during the operation.  increasing the number of stages caused increased pelletierine extraction.  assuming the existence of two boundary layer reactions zones in the aqueous solution mathematical model of the process was proposed. on the basis of the experimental results and the model the overall mass transfer coefficients were evaluated. references 1. el-sakka m. a. (2010)," phytochemistry alkaloids", 3rd edition, pp.7-22. 2. pѐrez c. and anesini a. (1994),"in vitro antibacterial activity of argentinian folk medicinal plants against salmonella typhi", journal of ethnopharmacol, vol. 44, pp.4146. 3. zhang j. (1995), "antiviral activity of tannin from pericarp of punica granatum against genital herpes simplex virus in vitro",china journal of chinese materia medica, vol. 20, pp.556558. 4. mavlyanov s. m., islambekov s. y., karimdzhanov a. k. and ismailov a. i. (1997), "polyphenols of pomegranate peels show marked anti-tumor and anti-viral action", chem. nat. compounds vol. 33, pp.98-99. 5. http://en.wikipedia.org/wiki/alkaloi d , (30 march 2011 at 20:22) 6. al-hemiri a. a., mohammed s. a., alsaadi r. b. (2009), "extraction of medicinal compounds from botanicals using bulk liquid membrane in rotating film contactor: recovery of vinblastine from catharanthus roseus", iraqi journal of chemical and petroleum engineering, vol. 10 (3), p.p. 25-30. 7. al-hemiri a. a. and noori w. o. (2009), "extraction of atropine from datura innoxia using liquid membrane technique", iraqi journal of chemical petroleum engineering, vol. 10(1), pp. 23-27. 8. titus msagati, luke chimuka and ewa cukrowska (2008), "sample preparation using liquid membrane extraction techniques", water sa vol. 34(3), pp. 421-427. 9. dimitrov k., gancel f., montastruca l. and nikov i. (2008), "liquid membrane extraction of bio-active amphiphilic substances: recovery of surfactin", biochemical engineering journal, vol. 42, pp. 248–253. 10. raizada p., vyas v. and sharma u. (2010), "liquid membrane http://en.wikipedia.org/wiki/alkaloid http://en.wikipedia.org/wiki/alkaloid adel a. al-hemiri, khalid m. abed, ayaad w. al-shahwany -available online at: www.iasj.net ijcpe vol.13 no.1 (march2012) 9 extraction and transport of amino acids using calix [6]arene", indian jornal of chemical technology, vol. 17, pp. 267-273. 11. mohammadi s., kaghazchi t. and kargari a. (2008), "a model for metal ion pertraction through supported liquid membranes", j. desalination, vol. 219, pp.324-334. 12. manzak a. and melek s. (2010), "extraction of acetic acid from aqueous solution by emulsion type liquid membrane using alamine 300 as a carrier", indian journal of chemical technology vol. 17, pp. 441-445. 13. dimitrov k., alexandrova s., saboni a., debray e. and boyadzhiev l. (2002), "recovery of zinc from chloride media by batch pertraction in rotating film contactor", journal of membrane science, vol. 207, pp.119-127. 14. dimitrov k., gancel f., montastruca l. and nikov i. (2008), "liquid membrane extraction of bio-active amphiphilic substances: recovery of surfactin", biochemical engineering journal, vol. 42, pp. 248–253. 15. dimitrov k., metcheva d. and boyadzhiev l. (2005), "integrated processes of extraction and liquid membrane isolation of atropine from atropa belladonna roots", journal of separation and purification technology, vol.46, pp.41-45. 16. boyadzhiev l., dimitrov k.and metcheva d. (2006), "integration of solvent extraction and liquid membrane separation: an efficient tool for recovery of bioactive substances from botanicals", chemical engineering science, vol. 61, pp. 4126-4128. 17. zhivkova s., dimitrove k., kyuchoukov g.and boyahzhiev l. (2006), "separation of zinc and iron by pertraction in rotating film contactor with kelex 100 as carrier", journal of separation and purification technology, vol. 37, pp.9-16. 18. dimitrov k., alexandrova s., boyadzhiev l., ruellan s. and burgard m. (1997), "recovery of copper from solution by rotating film pertraction", journal of separation and purification technology, vol.12, pp.165-173. 19. al-zobaiy khalid, (2011), "extraction of alkaloids form punica granatum l. roots using liquid membrane technique ", msc. thesis, chemical engineering department, college of engineering, university of baghdad. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol. 24 no.2 (june 2023) 123 – 135 eissn: 2618-0707, pissn: 1997-4884 *corresponding author: name: mohammed a. al-hejjaj, email: mohammed.mezher2008m@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. a review of the electrical submersible pump development chronology mohammed a. al-hejjaj a, *, dhifaf j. sadeq a, and omar al-fatlawi a, b a petroleum engineering department, college of engineering, university of baghdad, baghdad, iraq b wasm: energy and chemical engineering, curtin university, wa, australia abstract the electric submersible pump, also known as esp, is a highly effective artificial lift method widely used in the oil industry due to its ability to deliver higher production rates compared to other artificial lift methods. in principle, esp is a multistage centrifugal pump that converts kinetic energy into dynamic hydraulic pressure necessary to lift fluids at a higher rate with lower bottomhole pressure, especially in oil wells under certain bottomhole condition fluid, and reservoir characteristics. however, several factors and challenges can complicate the completion and optimum development of esp deployed wells, which need to be addressed to optimize its performance by maximizing efficiency and minimizing costs and uncertainties. to analyze the performance of esp deployed wells, the objective function must include various factors associated with fluids, reservoir inflow and outflow characteristics, and pump parameters. in particular, the inflow and outflow parameters include well configuration, and types of completion string (e.g. tubing sizes, and download completion hardware) while reservoir and fluid parameters include pressure, temperature, and pvt properties. pump parameters include gas vacuum fraction, electrical and mechanical constraints, power requirements, cable requirements, downhole conditions, etc. despite these challenges, esps' importance and efficiency necessitate an in-depth understanding of its origins and evolution over time, as well as the difficulties encountered in the oil industry. this paper aims to provide a comprehensive review of esp's origin and development, including all prior studies that have influenced optimum development. the literature review is divided into four main sections: experimental investigations, numerical simulation studies, mechanical modeling, and in-depth studies on production optimization. by providing an in-depth analysis of previous work in each area, this paper aims to contribute to ongoing efforts to enhance esps' performance and efficiency in the oil industry. keywords: electrical submersible pump; artificial lift; production optimization. received on 26/06/2022, received in revised form on 01/09/2022, accepted on 02/09/2022, published on 30/06/2023 https://doi.org/10.31699/ijcpe.2023.2.14 1introduction in the oil production industry, initial production from a well often occurs naturally, with the bottom hole pressure being sufficient to overcome pressure losses along the flow path to the separator [1, 2]. however, as the reservoir's energy is depleted, the well's productivity may decline to the point where it is no longer profitable or even becomes non-productive. this situation arises when there is insufficient energy to lift the oil to the surface or when the surface pressure exceeds the bottom hole pressure due to various factors. in such cases, artificial lift methods are employed to restore or optimize productivity [3]. among the different types of artificial lift systems used in the oil well industry, such as gas lift (gl), sucker rod pump (srp), progressive cavity pump (pcp), and hydraulic jet type pump, the electric submersible pump (esp) stands out due to its numerous advantages [4]. esps offer a high working rate ranging from 200 to 60,000 barrels per day (bpd) and can operate at depths of up to 15,000 feet (4,570 meters) [5]. furthermore, esp equipment is relatively cost-effective and can be easily operated both onshore and offshore. as a result, esps have gained significant attention and have been widely adopted in the oil industry. throughout the history of artificial lift, there have been continuous efforts to develop and enhance esp equipment and operational systems. numerous researchers have conducted investigations to address challenges and improve the performance of esps over time [6, 7]. these investigations have focused on advancing the technology, mitigating operational issues, and optimizing the design and efficiency of esp systems. in this paper, we aim to provide a comprehensive review of the development chronology of electrical submersible pumps. by examining the key milestones, technological advancements, and research findings in the field, we seek to contribute to the understanding of esps and their evolution. a better understanding of the historical context and improvements made in esp technology can inform future advancements and aid in optimizing the selection, installation, and operation of esp systems for efficient oil production. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:mohammed.mezher2008m@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2023.2.14 m. a. al-hejjaj et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 123 135 124 2historical overview a key milestone in the oil industry was the development of electrical submersible pumps (esps), which revolutionized artificial lift techniques. unlike other artificial lift methods like gas-lift or rod pumping, the creation of esp cannot be attributed to a single person or time period. in the late 1910s, a russian engineer named armais arutunoff played a significant role in the development of esp technology. in 1911, he established the russian electrical dynamo of arutunoff company (reda) and invented the submersible electric motor. recognizing the potential of his ideas, arutunoff embarked on a journey to germany in 1919 and subsequently moved to the united states in 1923 to seek support for further development [6]. in 1926, arutunoff was granted a us patent for the electrical submersible pump, covering the fundamental aspects of this innovative artificial lift method. the first successful esp installation took place in the el dorado field in kansas during the same year [8]. the complete esp unit comprises a motor, seal, and pump, which are run into the well at the bottom of the tubing string. a specialized three-conductor cable connects the motor to the surface, supplying power to the system. these components remain critical in modern esp systems [9]. reda, with over 90 years of experience, continues to be one of the world's leading producers of esp equipment for the oil industry. the company has obtained more than 90 patents related to submersible equipment. numerous other manufacturing firms in the us have connections to the initial reda company. esps have proven to be highly efficient in lifting large quantities of liquid, particularly in high-rate onshore and offshore applications. it is estimated that submersible pumping facilities now contribute to more than 10% of global oil production. over the course of its history, esp technology has undergone continuous improvement and innovation [10]. significant advancements occurred in the 1950s with the introduction of "seal units" or protectors featuring mechanical seals. these improved esp run times by providing better protection against well fluid leaking into the motor. addressing the challenge of gassy wells, the industry saw further progress in the early 1970s with the introduction of the first rotary gas separator, which enhanced gas separation capabilities [11]. another pivotal moment came in august 1977 when the initial variable speed esp device was installed. the variable speed drive (vsd) allowed for the adjustment of the electric current frequency driving the esp motor, enabling significant changes in the submersible pump's head performance [12]. by understanding the historical development of esps, researchers can appreciate the advancements made in the field and gain insights into the challenges that have been overcome. this knowledge serves as a foundation for ongoing research, development, and optimization of esp systems to ensure efficient and reliable oil production (fig. 1). fig. 1. esp components 3evolution of electric submersible pump studies over the past few years, the esp technique has gained significant attention from researchers worldwide [13]. this can be attributed to the availability of data and advancements in computer capabilities, which allow for efficient handling of multi-constraint tasks. as seen in fig. 2, the number of published papers on esp has steadily increased over the past two decades. this growth in research is due to the continued development of esp pumps and new technologies applied to different parts of esp equipment. these advancements have increased the lifespan and overall benefit of esp, making it a more attractive topic for researchers to explore. 4review of esp studies the optimization of electric submersible pumps (esps) is a complex process with many variables, and each piece of equipment requires optimization to achieve the best m. a. al-hejjaj et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 123 135 125 possible results and reach the optimal production level [6, 14]. this section highlights some notable researchers who have focused their research on various areas of esp operations and optimization tasks. previous research has shown that gas accumulation can cause the hydraulic head of the esp to deteriorate, and handling gas-liquid mixtures has become increasingly common over time. however, the actual mechanism of two-phase flow that affects esp performance remains unclear due to the complex geometry of multistage esps and the unknown gas bubble breakup mechanism and coalescence that create two-phase flow [15]. this literature review focuses on studies related to the optimization of electric submersible pumps (esps). it is divided into four sections: experimental studies, computational fluid dynamics (cfd) simulations, mechanistic modeling, and optimization studies. fig. 2. the number of esp publications against time (curtin university – library database) the experimental studies section discusses research that investigates various hydraulic elements affecting the boost pressure of esps. it covers topics such as the impacts of gas entrainment, fluid viscosity, and multiphase flow. the studies involve performance tests, correlation factors, adjustment factors, and empirical correlations to understand the behavior and performance of esps under different conditions. some of the challenges identified include the unknown gas bubble breakup mechanism, gas-liquid flow behavior, and the effect of fluid properties on friction losses. the numerical simulations studies section highlights the use of cfd techniques to study esp performance in single-phase and multiphase flow conditions. cfd provides a way to simulate the complex internal flow configurations of esps, which are challenging to explore through experiments. the studies discuss different modeling approaches, including the frozen-rotor interface model, transient simulations, and the sliding-mesh approach. they investigate factors such as impeller-volute interaction, unsteady flow, pressure fluctuations, and the effect of viscosity and gas presence on pump performance. the mechanistic modeling section focuses on developing models based on physical principles to understand esp performance. it discusses the concept of the ideal pump head (euler head) and deducting head losses caused by various mechanical elements. the section mentions friction losses, shock losses, leakage losses, recirculation losses, and diffuser losses as factors affecting pump efficiency. overall, the literature review highlights the complexity of esp optimization and the need for a multidisciplinary approach combining experimental research, numerical simulations, and mechanistic modeling. it identifies challenges such as understanding gas-liquid flow behavior, gas bubble dynamics, and the impact of fluid properties on esp performance. the studies provide insights into the factors influencing esp efficiency and suggest areas for further improvement. some suggestions include improving the understanding of gas bubble breakup mechanisms, developing more accurate models for friction losses, and considering the effects of surfactants and viscosity on pump performance. 4.1. experimental studies there are a number of hydraulic elements that affect the esp's boost pressure, including fluid characteristics, downhole environmental conditions, and multiphase flow. in recent years, the use of esps in oil production systems has expanded, which has led to an increase in research into the impacts of gas entrainment and fluid viscosity. ippen [16] performed over 200 performance tests on four centrifugal pump versions for oil viscosities up to 10,000 ssu (saybolt second universal). comparing oilhead to water-head, braking horsepower, and effectiveness against a reynolds-type. the dimensionless number was used to display the experimental findings. pump boosting pressure was correlated with generic correction factors as a result of this. hydraulic institute [17] for viscous liquid flow estimation using a conventional centrifugal pump with defined water performance, gave a usual experimental approach with adjustment factors. since the hydraulic institute's experiments focused on a small range of pump particular speeds, gülich (1999a, 1999b) [18, 19] and li [20] questioned the correctness of this approach. it was discovered that extrapolation was causing unreasonable errors if the range was widened. stepanoff [21] used one adjustment factor adjusted hq curves when water performance was known and proposed a reynolds-type number. gülich created a model that evaluates viscous and hydraulic frictions to calculate centrifugal pump boosting pressure. friction losses on the disk and along the flow channel hinder centrifugal pumps' capacity to handle high-viscosity fluids. gülich also noted that pump shape, fluid properties, and heat conditions affect friction losses. further experimental experiments were done by amaral [22] and solano [23] found there were insufficient correction factors to forecast the esp boosting pressure from the graphs from the hydraulic institute and empirical studies in the literature. barrios [24], banjar [25] and others have reported inconsistent results between experimental measurement and projections based on known correlations or charts. solano [23] tested fluid viscosities of a seven-stage mixed-type esp were altered by testing it with oils flowing at various temperatures. it was determined what the esp stage-by-stage pressures would be at three m. a. al-hejjaj et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 123 135 126 different precise speed levels. verification of the experimental results was carried out using the conservation equations of momentum and he found esp's hydraulic head can be linked to three dimensionless variables. murakami [26, 27] performed the first experimental investigation on the performance of centrifugal pumps with gas entrainment. in order to observe the activity of bubbles in real-time, a transparent impeller pump was used. the pump’s total head decreased as a result of the additional work required to supply air. researchers have now carried out more experiments and numerical modeling of pump performance in case of gas flow conditions. experiments on the performance of esp in gas-liquid flow circumstances have been conducted by cirilo [28], pessoa and prado [29], beltur [30], duran [31], zapata [32], gamboa [33], and salehi [34], among other, for assessing esp performance at tualp, cirilo built flow loops for testing purposes. he used the tap water and air as the acting fluids to examine the water and air-water performance of 3 various forms of esps in relation to gvf, intake pressure, and rotational speeds. according to the findings of the study, mixed-type pumps may. pessoa investigated the two-phase esp performance with an experimental 22-stage gc-6100 pump. in his research, he discovered that the average esp behavior diverged significantly from the pressure rise measured at each level. additionally, the borders of the surging and gas locking phenomena were observed. after the initial surge in pressure, there was a second period where the slope of pressure increments against the flow rate changed once again in test curves. duran, beltur, zapata, and salehi used the same investigational flow loop as pessoa to undertake large experimental evaluations of esp work in mutually liquid and gas-liquid flow regimes. beltur looked examined how esp running degraded in the presence of gas at various input gvfs and pressures. the input gvf is the most critical factor in esp increasing pressure under gassy flow, according to data analysis. with gvfs above 6%, the pumping head deteriorates more quickly. duran and zapata created empirical correlations to forecast pressure increments through the stage and flow regimes boundaries. zapata as well conducted further tests with a comprehensive range of rotational speeds to investigate the implications on esp's average efficiency. salehi conducted similar tests using a 14-stage te-2700 esp, looking into the effects of stage number, intake pressure, and fluid characteristics. the gvf was observed to vary stage by stage only when the esp two-phase boosting pressure exceeded a particular threshold, under which the decline was minor plus irrespective of stage number. in summary, as gvf approached the point where downstream pump boosting pressure is better than upstream, degradation of the head pump became more apparent and stage number was impacted. barrios [35], barrios and prado [36] observed that as input gvfs rose and pump speeds fell, bubbles proliferated. esp's ability to manage gas-liquid mixtures was negatively influenced by bubble behaviors, as seen in fig. 3 by the association between increased bubble size and decreased pump performance. researchers found that esp channels with larger gvfs exhibited distinct flow patterns. fig. 3. flow via the impeller channel [35] estevam [37] and [38] classified esp impeller flow patterns as bubbly, transition, and elongated bubble. gamboa [33, 13] did more complete experimental research on two-phase flow in esp impellers. fig. 4 shows their characteristic flow pattern map under a particular flow state. curves denote the transition boundaries between homogeneous, bubbly, gas-pocket, and segregated flow. fig. 4. flow patterns map [33] verde, [39] used high-speed and high-resolution imagery to conduct flow pattern recognition studies inside a revolving esp impeller. they found that the flow pattern in the impeller has a direct impact on the degree of pump performance decline. as pump performance deteriorates and operational instabilities become more prevalent, gas pocket flow patterns occur more frequently. several technologies were suggested schäfer [40]; neumann [41] to understand the inner flows within a centrifugal pump; however, the researchers needed adjustments to the geometry of the pump, and their implementation was challenging. as a result, the internal m. a. al-hejjaj et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 123 135 127 flow structures had to be mounted hirect (highresolution gamma-ray computed tomography) in order to see through the opaque pump casing or volute. to further complicate the analysis of the given experimental results data processing using time-averaged, rotationsynchronized ct scans. the working fluid in the esp gas-liquid research was tap water, but the gas form was compressed air or nitrogen. trevisan [42, 43], banjar [25], and paternost [44] conducted numerous recent experimental experiments concentrating on esp gas-management capability under viscous fluid flow. trevisan, trevisan and prado examined the influence of viscosity on liquid/gas 2-phase flow through esp with a visualization prototype constructed from original esp components with minimum geometric modifications. inside the impeller channels, they discovered four liquid/air flow patterns: agglomerated bubble, segregated gas, gas pocket and intermittent gas flows. the agglomerated bubble flow was shown to be the cause of the pressure-surging trend, which is the start of pump head deterioration owing to gas entrainment. additionally, the scientists noticed that the rise in viscosity triggered surging at significantly smaller inlet gvfs. banjar [25] made similar findings in their experiments. paternost [44] studied the performance and impacts of free gas entrainment on a centrifugal pump handling single-phase viscous liquid. as liquid viscosity rose, they found that pump head degradation was being driven by the stagnation of huge gas-pocket growth. surfactants are hydrophobic and hydrophilic molecules that adsorb more readily at the boundary between continuous and dispersed liquids. they lower the surface tension of the continuous phase in the process [45]. however, there were few investigations on the effects of surfactants on pump performance in two-phase flow situations. ogata [46] experimentally measured pump head and hydraulic efficiency curves to investigate the effect of surfactant additives on centrifugal pump performance in single-phase operation. they found that when the concentration of surfactant rose, so did the pump's total head and efficiency. chandel [47] investigated the drag-reducing additive effect on centrifugal slurry pump performance in experimental research. the results reveal that by adding the drag-reducing additive, the pump head and efficiency improve at a rotating speed. 4.2. numerical simulations studies computational fluid dynamics (cfd) is becoming an increasingly powerful technique for studying the performance of the pump unit in single-phase and multiphase flow settings as computer technology progresses. due to the overly complex geometries of esp, it is challenging to explore the inner speed and pressure through an experiment. cfd, on the other hand, provides an alternative method of simulating complex interior flow configurations[48]. a centrifugal pump has a stationary volute and an impeller revolving at a predetermined angular velocity. the revolving and stationary sections of an esp are located in the spinning and stationary computational domains in cfd, respectively. the inner flow inside pumps, including velocity and pressure fields, can be modeled utilizing a 3d modal by cfd with the frozen-rotor interface model asuaje, [49]; maitelli [50]; rajendran [51] in addition to flow recirculation and separation cheah [52]; zhu [53]. the frozen-rotor model is deemed a steady-state simulation because it maintains two different reference frames for the rotational and stationary components. centrifugal pumps' dynamic flow topologies were studied using transient simulations and the sliding-mesh approach by gonza´ lez,[54, 55] and huang [56, 57]. the flow of an unsteady single-phase centrifugal pump was investigated by gonzalez et al. using numerical models that included impeller-volute contact. the impeller-volute interaction-induced unstable flow actions inside a centrifugal pump were captured by employing the sliding mesh approach to solve viscous, incompressible navier-stokes (n-s) equations. numerical calculations were used to establish a relationship between global factors such as torque and impeller relative position, as well as secondary flow in the volute. the dynamic interaction between the impeller and the spiral may be accurately predicted using this method. using the sliding mesh technique, huang investigated the effects of impeller and diffuser vanes on unsteady flow and pressure fluctuations. the impeller blade passing frequency was found to have a significant impact on the global variables, as validated by this investigation. engineers can use cfd to analyze how viscosity affects centrifugal pump performance in addition to building turbomachinery. it was found that centrifugal pumps with viscous fluids can be studied by conducting both experimental research and numerical simulation [58, 59]. sirino [60] and stel, [61]investigated viscosity's effect upon single-stage and 3-stage esps with the same pump design. in their work, they used similar computational methodologies, such as the sst turbulence model with transient rotor-stator systems. both simulation and experiment results matched well throughout a wideranging of fluid viscosity. cfd has also been used to emulate pump performance in case of gas presence, such as cavitation and free-gas entrainment flow. barrios [35, 62] performed multiphase cfd simulations on a single-stage esp impeller using unique models of bubble size and drag coefficient predictions. their theories matched experimentally observed streamlines and gas-accumulation zones. qi [63] developed esps with the high-level-temperature gas-liquid 2-phase flow for geothermal applications. the planned mix-type centrifugal impeller and diffuser were adjusted for better gas handling and higher efficiency m. a. al-hejjaj et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 123 135 128 across a wide range of production rates using cfd simulations. zhu and zhang [64] conducted 3-stage esp simulations with an impeller and a diffuser in each step using multiphase cfd. comparing their findings to experimental observations, it was clear that bubble size played a significant role in esp performance under gaseous conditions. changes in local pressure, variations in gas void percentages, and bubble breakup or coalescence are examples of transient multiphase flow events in esp. to more accurately simulate the hydrodynamics of gas-liquid two-phase flow in a rotating centrifugal pump, unstable cfd simulation code should be combined with a multiphase flow model and transient rotor-stator approach to account for impeller and diffuser interactions. on the other hand, transient cfd simulations have a much larger computational cost than steady-state simulations. 4.3. mechanistic modeling after deducting head losses owing to several mechanical losses elements such as (friction, shock, leakage, recirculation, diffuser, and disk), the efficient and ideal pump head can be defined as euler head (h e), as indicated in equation: 𝐇 = 𝐇𝐄 − 𝐇𝐟𝐫𝐢𝐜𝐭𝐢𝐨𝐧 − 𝐇𝐬𝐡𝐨𝐜𝐤 − 𝐇𝐥𝐞𝐚𝐤𝐚𝐠𝐞 − 𝐇𝐫𝐞𝐜𝐢𝐫𝐜𝐮𝐥𝐚𝐭𝐢𝐨𝐧 − 𝐇𝐝𝐢𝐟𝐟𝐮𝐬𝐞𝐫 − 𝐇𝐝𝐢𝐬𝐤 (1) where: hfriction : losses because of fluid friction in the impeller, hshock : losses when changing the flowrate from the design rate, hleakage : losses between rotating and stationary parts, hrecirculation : losses from the shaft due to pressure gradient, hdiffuser : losses due to the friction on diffuser walls, hdisk : losses due to rotating disk and fluid. where each factor was discussed and researched by several researchers as will be summarized in tables. the friction losses in the interior pump impeller are summarized in table 1. according to takacs (2009), friction losses rise with liquid rate and are caused by fluid friction in the impeller. table 1. models of friction loss in the literature references models m a c a l u s o [ 6 5 ] ( s u n a n d p r a d o [ 6 6 ] t h i n [ 6 7 ] ℎ𝑓𝑟𝑖𝑐𝑡𝑖𝑜𝑛 = 𝑏2 (𝐷2 − 𝐷1)(𝑊1 + 𝑊2) 2 8𝑔𝑠𝑖𝑛𝛽2𝑟𝐻 it o [ 6 8 ] c h u r c h i l l [ 6 9 ] ( s u n a n d p r a d o [ 6 6 ] ℎ𝑓𝑟𝑖𝑐𝑡𝑖𝑜𝑛 = 𝑓𝛾𝛽𝜔 𝑄 2 8𝑔𝐷𝐻 𝜋 2𝑏𝑚 2 𝑠𝑖𝑛3𝛽𝑚 it o ¯ a n d n a n b u [ 7 0 ] b i n g , ta n [ 7 1 ] ℎ𝑓𝑟𝑖𝑐𝑡𝑖𝑜𝑛 = 𝑁𝑎 𝑓𝛾𝛽𝜔 𝑠 𝐷𝐻 𝑊1 2 + 𝑊2 2 4𝑔 zh u [ 1 5 ] ℎ𝑓𝑟𝑖𝑐𝑡𝑖𝑜𝑛 = 𝑓𝐹𝐼 𝑉1 2𝐿1 2𝑔𝐷1 shock losses in centrifugal pumps have not been widely studied in the past since they are insignificant at the best efficiency point bep. as seen in table 2, there are just a few empirical relationships available. table 2. models of shock losses in the literature references models s t e p a n o f f [ 2 1 ] a m a r a l [ 7 2 ] th i n [ 6 7 ] ℎ𝑠ℎ𝑜𝑐𝑘 = 𝑘𝑠ℎ𝑜𝑐𝑘 (𝑄 − 𝑄𝐵𝐸𝑃 ) 2 s u n a n d p r a d o [ 6 6 ] m a c a l u s o [ 6 5 ] th i n [ 6 7 ] ℎ𝑠ℎ𝑜𝑐𝑘 = 𝑘𝑠ℎ𝑜𝑐𝑘 2𝑔 ( 𝑄 − 𝑄𝐵𝐸𝑃 𝑄𝐵𝐸𝑃 𝑢1) 2 zh u [ 1 5 ] ℎ𝑇𝐼 = 𝑓𝑇𝐼 𝑉1 2 2𝑔 according to tackas (2009), leakage losses, which are losses caused by clearances between spinning and immobile sections of the pump stage (at the impeller eye, through balance holes, and so on), decrease as liquid rates rise. similar empirical equations for calculating leakage loss were proposed by aungier [73] and bing [71]: ℎ𝑙𝑒𝑎𝑘𝑎𝑔𝑒 = 𝑄𝑐1 𝑄𝑐1𝑢𝑐1𝑢2 2𝑄𝑔 (2) where qc1 is the leaking fluid volume, uc1 is the leakage fluid velocity, and q is the pump's optimum flow rate. loss of recirculation occurs in a rotating centrifugal pump due to squandered fluid energy that continuously emerges from the shaft due to an unfavourable pressure slope from the impeller input to output. the unfavourable pressure gradient grows as the liquid flow rate declines, resulting in more severe head loss due to fluid recirculation (table 3). m. a. al-hejjaj et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 123 135 129 table 3. models of recirculation loss in literature references models tuzson [75] gülich [18] the researches [66, 76] asserted that diffuser loss is primarily driven by friction on the diffuser walls. table 4 shows the diffuser loss calculation methods that were used in the prediction models. the majority of the equations are the same as the friction loss formulas in table 1. table 4. models diffuser loss in the literature references models ito [68, 70] churchill [69] shah [77] sun and prado [78] bing [71] shah [77] amaral [22] ladouani and nemdili [79] stepanoff [21] identified disk friction losses as the result of contact between a rotating disk and fluid. as a result of the viscous shear forces acting on the disk surfaces, more power is spent to keep the disk moving (table 5). table 5. models disk friction losses in the literature references models s u n a n d p r a d o [ 6 6 ] amaral [22] th i n [ 6 7 ] van esch [80] cm is an empirical constant 4.4. production optimization studies the main takeaway from the provided information is that optimizing the performance of a large oilfield with numerous esp-boosted wells in a complex production network is a challenging task. production engineers need to make decisions regarding the adjustment of individual esp frequencies and the shut-in of high water-producing wells to optimize the production system. the use of historical and real-time data, along with modeling and mathematical optimization techniques, plays a crucial role in diagnosing and optimizing the functioning of esplifted wells. controlling and optimizing the performance of a huge oilfield with hundreds of esp (electric submersible pump)-boosted wells placed in a wide production network can be a very tough task. on a daily/ weekly basis, production engineers have to make decisions on (1) the update of individual esp frequencies and (2) the shut-in of high water-producing wells. the optimization of production systems in the oil and gas industry with practical operating constraints has gotten a lot of attention, as evidenced by various publications. bates [81] highlight the use of historical and real-time data during startup, operation, and shutdown to diagnose and optimize the functioning of esp-lifted wells, as well as modeling. castro [82] and takacs [83] explain the advantages of revising pump design to enhance esp performance stanko and golan [84] and stanko [85] designed and deployed a model-based advice system to support the production management of the rubiales field. the method involves applying mathematical optimization techniques to a "canned" commercial software-based numerical model of a production network. the network model accurately replicates the actual production system in its current condition (e.g., tuned to and containing field data). the model computes the rates, pressures, and temperatures along the system, assuming pseudo-steady state inflow deliverability. the optimization is designed to increase oil production or economic revenue by altering esp frequencies while concurrently meeting several operational constraints. generally, esp optimization algorithms (table 6) are procedures designed to use many parameters from producing well (completion dimension, esp equipment dimension, real-time operating parameters dimension) to m. a. al-hejjaj et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 123 135 130 get a new set of operating conditions that will be the best fits and the desired target function whether it is maximum production, maximum pump efficiency, or others. depending on the specific case. to achieve successful optimization, it is critical to consider factors such as historical and real-time data analysis, modeling, diagnostic procedures, and the application of mathematical optimization techniques. furthermore, leveraging ai, machine learning, and digital monitoring systems can greatly enhance the efficiency and effectiveness of esp optimization. for further improvement, it could be beneficial to explore the integration of advanced technologies such as advanced data analytics, real-time optimization algorithms, and automation. additionally, researching and implementing predictive maintenance solutions can help reduce downtime and improve the overall reliability of esp systems. continuous research and development in the field of esp optimization, incorporating the latest advancements in technology, can lead to further improvements in oilfield production efficiency and performance. table 6. production optimization in literature references application al-jasmi [86] study esp smart flow combines quality and control data in real time for diagnostics and optimization adesanwo [87] investigate intelligent surveillance of electrical submersible pump systems using smart alarming shuwaikhat [88] they created an improved approach and monitoring system that combines all esp parameters and factors onto a single platform. a diagnostic procedure, production optimization, esp track and trip prediction alarm, esp dashboard with production rates, and field overview are all capabilities of the system that can be used to determine quick remedial action. this method operates as a quality assurance system, employing computational models to forecast esp trips or failures in advance. jansen van rensburg [89] they talked about how ai could be used to develop a predictive maintenance system for esps. also presented is how to deploy an autonomous surveillance solution for esp systems utilizing the predictive maintenance solution, and how to do so using artificial intelligence ai technology in conjunction with a cloud-based internet of things iot platform. jansen van rensburg and kamin [90] predictive models based on machine learning to enable preventative maintenance and prevent esp downtime. sanusi [91] they use machine learning to build models that can be used to forecast pump intake pressure pip when it is not available or to confirm gauge readings when they are suspicious. using rsm and ann, an empirical equation for predicting pip was established and then optimized. diker [92] based on data from the mittelplate oil field, wintershall dea is creating a digital system with partners to monitor and optimize electrical submersible pump (esp) performance. this technology uses machine learning (ml) models that are fed by historical data to alert engineers and operators when operating conditions are drifting outside of the operating envelope, allowing them to avoid potential performance issues. bermudez [93] by using intelligent maximum production (imp) algorithm the could maximize production from tight oil wells during the first high-output stage, as well as prevention of gas-locking as gas production increases later. 5conclusions the main objective of this study is to deliver a general review of the development of the esp optimization problem and the available studies and applications to solve the problem at hand. after reviewing a fair number of studies and papers on the problem of esp optimization the following conclusions were made: 1the solutions available for the esp optimization problem were evolved rationally with the rising computational power and the computer abilities that were available to be utilized to the solution of the problem. 2the availability of the esp data and their amount plays a major part in the selection of the optimization technique that will be used for the task and the degree of accuracy that will be a result of this technique. 3in the literature, there are studies of centrifugal pump performance under gassy flow. however, the gas bubble behavior and its impact on two-phase flow hydrodynamics in rotating esps are still a mystery. 4the surfactant effect was not taken into account in the majority of esp pressure-boosting experiments. under gassy flow conditions with different amounts of surfactants, extensive experimental evaluations of esp stage pressure increment should be done. 5it is highly challenging to see esp interior flow structures and bubble movement when the impeller is rotating because of the small and complex geometry. 6cfd simulations can provide detailed information of flow structures inside the impeller. 7more attention was made to forecasting pump performance in two-phase systems rather than flow structures inside esps in previous numerical simulation studies. 8mechanistic modeling of esp two-phase performance is still preliminary in the literature. experimental investigations are insufficient on esp two-phase flow behaviors including flow patterns and transition boundaries. the development and m. a. al-hejjaj et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 123 135 131 validations are also critical for the accuracy of mechanistic model predictions. nomenclature ai artificial-intelligence als artificial lift selection bep best efficiency point on the pump curve bfpd barrels of fluid per day dht downhole tool/ gauge fvf/bo formation volume factor gvf gas volumetric fraction gor gas to oil ratio kva kilo-volt ampere (power capacity/ requirement) nlap net lift above pump pi productivity index pi intake/ annulus pressure pd discharge pressure qc quality control re reynolds number tualp tulsa university artificial lift projects ti intake/ annulus temperature tm motor temperature ror recommended operating range whp well head pressure/ tubing pressure ga genetic-algorithm ipr inflow performance relationship minlp mixed-integer-non-linear-programing stb stock tank barrel vsd variable speed drive references [1] brown, k., the technology of artificial methods. 1980, pennwell books. [2] odah, hussain amar, mohammad jawad hamed, mohammad salim reshk, and dhifaf jaafar sadeq. "optimization of gas lift production of oil wells." in aip conference proceedings, vol. 2651, no. 1. aip publishing, 2023. https://doi.org/10.1063/5.0111682 [3] aljuboori, mustafa, mofazzal hossain, omar al-fatlawi, akim kabir, and abbas radhi. "numerical simulation of gas lift optimization using genetic algorithm for a middle east oil field: feasibility study." in international petroleum technology conference. onepetro, 2020. https://doi.org/10.2523/iptc-20254-ms [4] al-janabi, m.a., et al. numerical simulation of gas lift optimization using artificial intelligence for a middle eastern oil field. in abu dhabi international petroleum exhibition & conference. 2021. https://doi.org/10.2118/207341-ms [5] n.jreou, g., increasing of oil field productivity by implementation of re-entry horizontal injection well, case study. iraqi journal of chemical and petroleum engineering, 2012. 13(3): p. 17-34. [6] takacs, g., electrical submersible pumps manual: design, operations, and maintenance. 2017: gulf professional publishing. [7] worth, d., al-safran, e., choudhuri, a., & aljasmi, a. (2019). assessment of artificial lift methods for a heavy oil field in kuwait. journal of petroleum science and engineering, 180, 835843. https://doi.org/10.1016/j.petrol.2019.06.012 [8] armais, a., electrically-driven pump. 1926, google patents. [9] nguyen, t., artificial lift methods: design, practices, and applications. 2020: springer nature. https://doi.org/10.1007/978-3-03040720-9 [10] saputra, m. n. w., ciptaningsih, r., & febryana, n. e. (2021, october). unlocking esp potential in high gas/liquid ratio wells using gas lock prevention control in west java field, indonesia. in spe/iatmi asia pacific oil & gas conference and exhibition. onepetro. https://doi.org/10.2118/205643-ms [11] bunnelle, p.r., liquid-gas separator unit. 1975, google patents. [12] divine, d.l. a variable speed submersible pumping system. in spe annual technical conference and exhibition. 1979. onepetro. https://doi.org/10.2118/8241-ms [13] gamboa, j. and m. prado, review of electricalsubmersible-pump surging correlation and models. spe production & operations, 2011. 26(04): p. 314-324. https://doi.org/10.2118/140937-pa [14] al-janabi, m.a.m. and o. al-fatlawi, gas lift optimization: a review. aip conference proceedings, 2022. 2443(1): p. 030013. https://doi.org/10.1063/5.0091901 [15] zhu, j., experiments, cfd simulation and modeling of esp performance under gassy conditions. 2017: the university of tulsa. [16] ippen, a., the influence of viscosity on centrifugal pump performance. issue 199 of fritz engineering laboratory report, asme paper no. 1945, a-45-57. [17] institute, h., tentative standards of hydraulic institute: charts for the determination of pump performance when handling viscous liquids. 1948. [18] gülich, j., pumping highly viscous fluids with centrifugal pumps—part 1. world pumps, 1999. 1999(395): p. 30-34. https://doi.org/10.1016/s0262-1762(00)87528-8 [19] gülich, j., pumping highly viscous fluids with centrifugal pumps—part 2. world pumps, 1999. 1999(396): p. 39-42. https://doi.org/10.1016/s0262-1762(00)87492-1 [20] li, w.g., experimental investigation of performance of commercial centrifugal oil pump. 2002. https://doi.org/10.1115/1.1458581 [21] stepanoff, a.j.j.t., design, and application, centrifugal and axial flow pumps. 1957. https://doi.org/10.2523/iptc-20254-ms https://doi.org/10.2118/207341-ms https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/338 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/338 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/338 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/338 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/338 https://books.google.iq/books?hl=en&lr=&id=isupdwaaqbaj&oi=fnd&pg=pp1&dq=%5b6%5d%09takacs,+g.,+electrical+submersible+pumps+manual:+design,+operations,+and+maintenance.+2017:+gulf+professional+publishing.&ots=jvabmejvx3&sig=yji2lnspqrygrgh9knp712szqgq&redir_esc=y#v=onepage&q=%5b6%5d%09takacs%2c%20g.%2c%20electrical%20submersible%20pumps%20manual%3a%20design%2c%20operations%2c%20and%20maintenance.%202017%3a%20gulf%20professional%20publishing.&f=false https://books.google.iq/books?hl=en&lr=&id=isupdwaaqbaj&oi=fnd&pg=pp1&dq=%5b6%5d%09takacs,+g.,+electrical+submersible+pumps+manual:+design,+operations,+and+maintenance.+2017:+gulf+professional+publishing.&ots=jvabmejvx3&sig=yji2lnspqrygrgh9knp712szqgq&redir_esc=y#v=onepage&q=%5b6%5d%09takacs%2c%20g.%2c%20electrical%20submersible%20pumps%20manual%3a%20design%2c%20operations%2c%20and%20maintenance.%202017%3a%20gulf%20professional%20publishing.&f=false https://books.google.iq/books?hl=en&lr=&id=isupdwaaqbaj&oi=fnd&pg=pp1&dq=%5b6%5d%09takacs,+g.,+electrical+submersible+pumps+manual:+design,+operations,+and+maintenance.+2017:+gulf+professional+publishing.&ots=jvabmejvx3&sig=yji2lnspqrygrgh9knp712szqgq&redir_esc=y#v=onepage&q=%5b6%5d%09takacs%2c%20g.%2c%20electrical%20submersible%20pumps%20manual%3a%20design%2c%20operations%2c%20and%20maintenance.%202017%3a%20gulf%20professional%20publishing.&f=false https://patents.google.com/patent/us1610726a/en https://patents.google.com/patent/us1610726a/en https://doi.org/10.2118/205643-ms https://patents.google.com/patent/us3887342a/en https://patents.google.com/patent/us3887342a/en https://doi.org/10.2118/8241-ms https://doi.org/10.2118/140937-pa https://doi.org/10.1063/5.0091901 https://www.proquest.com/openview/49f85051f9d1ea6fbcd59af2c65427d9/1?pq-origsite=gscholar&cbl=18750 https://www.proquest.com/openview/49f85051f9d1ea6fbcd59af2c65427d9/1?pq-origsite=gscholar&cbl=18750 https://www.proquest.com/openview/49f85051f9d1ea6fbcd59af2c65427d9/1?pq-origsite=gscholar&cbl=18750 https://doi.org/10.1016/s0262-1762(00)87528-8 https://doi.org/10.1016/s0262-1762(00)87492-1 https://doi.org/10.1115/1.1458581 m. a. al-hejjaj et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 123 135 132 [22] amaral, g., v. estevam, and f.a. franca, on the influence of viscosity on esp performance. spe production & operations, 2009. 24(02): p. 303311. https://doi.org/10.2118/110661-pa [23] solano, e.a., viscous effects on the performance of electro submersible pumps (esp's). 2009, university of tulsa. [24] barrios, l., et al. esp technology maturation: subsea boosting system with high gor and viscous fluids. in spe annual technical conference and exhibition. 2012. onepetro. https://doi.org/10.2118/159186-ms [25] banjar, h., j. gamboa, and h.-q. zhang. experimental study of liquid viscosity effect on two-phase stage performance of electrical submersible pumps. in spe annual technical conference and exhibition. 2013. onepetro. https://doi.org/10.2118/166374-ms [26] murakami, m. and k. minemura, effects of entrained air on the performance of a centrifugal pump: 1st report, performance and flow conditions. bulletin of jsme, 1974. 17(110): p. 1047-1055. https://doi.org/10.1299/jsme1958.17.1047 [27] murakami, m. and k. minemura, effects of entrained air on the performance of centrifugal pumps: 2nd report, effects of number of blades. bulletin of jsme, 1974. 17(112): p. 12861295. https://doi.org/10.1299/jsme1958.17.1286 [28] cirilo, r., air-water flow through electric submersible pumps. 1998, university of tulsa, department of petroleum engineering. [29] pessoa, r. and m. prado. experimental investigation of two-phase flow performance of electrical submersible pump stages. in spe annual technical conference and exhibition. 2001. onepetro. https://doi.org/10.2118/71552ms [30] beltur, r., et al. analysis of experimental data of esp performance under two-phase flow conditions. in spe production and operations symposium. 2003. onepetro. https://doi.org/10.2118/80921-ms [31] duran, j., pressure effects on esp stages airwater performance. 2003, university of tulsa. [32] zapata, l.c., rotational speed effects on esp two-phase performance. 2003, university of tulsa. [33] gamboa, j., prediction of the transition in twophase performance of an electrical submersible pump. 2009: proquest. [34] salehi, e., esp performance in two-phase flow through mapping and surging tests at various rotational speeds and intake pressures. 2012, the university of tulsa tulsa, ok, usa. [35] barrios, l. j. (2007). visualization and modeling of multiphase performance inside an electrical submersible pump. proquest. [36] barrios, l. and m.g. prado, experimental visualization of two-phase flow inside an electrical submersible pump stage. journal of energy resources technology, 2011. 133(4). https://doi.org/10.1115/1.4004966 [37] estevam, v., a phenomenological analysis about centrifugal pump in two-phase flow operation. a phd thesis at faculdade de engenharia mecânica, universidade estadual de campinas, brazil, 2002. [38] estevam, v., f. frança, and f. alhanati. mapping the performance of centrifugal pumps under two-phase conditions. in proceedings of the 17th international congress of mechanical engineering, sao paulo, brazil. 2003. [39] verde, w.m., et al., experimental study of gasliquid two-phase flow patterns within centrifugal pumps impellers. experimental thermal and fluid science, 2017. 85: p. 37-51. https://doi.org/10.1016/j.expthermflusci.2017.02. 019 [40] schäfer, t., et al., application of gamma-ray computed tomography for the analysis of gas holdup distributions in centrifugal pumps. flow measurement and instrumentation, 2015. 46: p. 262-267. https://doi.org/10.1016/j.flowmeasinst.2015.06.0 01 [41] neumann, m., et al., an experimental study on the gas entrainment in horizontally and vertically installed centrifugal pumps. journal of fluids engineering, 2016. 138(9). https://doi.org/10.1115/1.4033029 [42] trevisan, f.e., modeling and visualization of air and viscous liquid in electrical submersible pump. 2009, university of tulsa. [43] trevisan, f.e. and m. prado, experimental investigation of the viscous effect on two-phaseflow patterns and hydraulic performance of electrical submersible pumps. journal of canadian petroleum technology, 2011. 50(04): p. 45-52. https://doi.org/10.2118/134089-pa [44] paternost, g.m., a.c. bannwart, and v. estevam, experimental study of a centrifugal pump handling viscous fluid and two-phase flow. spe production & operations, 2015. 30(02): p. 146-155. https://doi.org/10.2118/165028-pa [45] de gennes, p.-g., f. brochard-wyart, and d. quéré, capillarity and wetting phenomena: drops, bubbles, pearls, waves. vol. 315. 2004: springer. https://doi.org/10.1007/978-0-38721656-0 https://doi.org/10.2118/110661-pa https://doi.org/10.2118/159186-ms https://doi.org/10.2118/166374-ms https://doi.org/10.1299/jsme1958.17.1047 https://doi.org/10.1299/jsme1958.17.1286 https://doi.org/10.2118/71552-ms https://doi.org/10.2118/71552-ms https://doi.org/10.1115/1.4004966 https://doi.org/10.1115/1.4033029 https://doi.org/10.2118/134089-pa https://doi.org/10.2118/165028-pa m. a. al-hejjaj et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 123 135 133 [46] ogata, s., a. kimura, and k. watanabe, effect of surfactant additives on centrifugal pump performance. 2006. https://doi.org/10.1115/1.2201643 [47] chandel, s., s. singh, and v. seshadri, effect of additive on the performance characteristics of centrifugal and progressive cavity slurry pumps with high concentration fly ash slurries. coal combustion and gasification products, 2011. 3(4): p. 67-74. https://doi.org/10.4177/001c.12372 [48] mahmood, h. and o. al-fatlawi, construction of comprehensive geological model for an iraqi oil reservoir. iraqi geological journal, 2021. 54: p. 22-35. https://doi.org/10.46717/igj.54.2f.3ms-2021-1220 [49] asuaje, m., et al., numerical modelization of the flow in centrifugal pump: volute influence in velocity and pressure fields. international journal of rotating machinery, 2005. 2005(3): p. 244255. https://doi.org/10.1155/ijrm.2005.244 [50] maitelli, c.d.p., f. bezerra, and w. mata, simulation of flow in a centrifugal pump of esp systems using computational fluid dynamics. brazilian journal of petroleum and gas, 2010. 4(1). [51] rajendran, s. and k. purushothaman, analysis of a centrifugal pump impeller using ansyscfx. international journal of engineering research & technology, 2012. 1(3): p. 1-6. [52] cheah, k., et al., numerical flow simulation in a centrifugal pump at design and off-design conditions. international journal of rotating machinery, 2007. 2007. https://doi.org/10.1155/2007/83641 [53] zhu, j. and h.-q. zhang, mechanistic modeling and numerical simulation of in-situ gas void fraction inside esp impeller. journal of natural gas science and engineering, 2016. 36: p. 144154. https://doi.org/10.1016/j.jngse.2016.10.020 [54] gonza´ lez, j., et al., numerical simulation of the dynamic effects due to impeller-volute interaction in a centrifugal pump. j. fluids eng., 2002. 124(2): p. 348-355. https://doi.org/10.1115/1.1457452 [55] gonzález, j. and c. santolaria, unsteady flow structure and global variables in a centrifugal pump. 2006. https://doi.org/10.1115/1.2234782 [56] huang, s., et al., numerical simulation of unsteady flow in a multistage centrifugal pump using sliding mesh technique. progress in computational fluid dynamics, an international journal, 2010. 10(4): p. 239-245. https://doi.org/10.1504/pcfd.2010.034454 [57] huang, s., et al., unsteady numerical simulation for gas–liquid two-phase flow in self-priming process of centrifugal pump. energy conversion and management, 2014. 85: p. 694-700. https://doi.org/10.1016/j.enconman.2014.03.023 [58] shojaeefard, m., et al., numerical study of the effects of some geometric characteristics of a centrifugal pump impeller that pumps a viscous fluid. computers & fluids, 2012. 60: p. 61-70. https://doi.org/10.1016/j.compfluid.2012.02.028 [59] shojaeifard, m., f. boyaghchi, and m. ehghaghi, experimental study and threedimensional numerical flow simulation in a centrifugal pump when handling viscous fluids. 2006. [60] sirino, t., h. stel, and r.e. morales. numerical study of the influence of viscosity on the performance of an electrical submersible pump. in fluids engineering division summer meeting. 2013. american society of mechanical engineers. https://doi.org/10.1115/fedsm201316374 [61] stel, h., et al. cfd investigation of the effect of viscosity on a three-stage electric submersible pump. in fluids engineering division summer meeting. 2014. american society of mechanical engineers. https://doi.org/10.1115/fedsm201421538 [62] barrios, l., m.g. prado, and f. kenyery. cfd modeling inside an electrical submersible pump in two-phase flow condition. in fluids engineering division summer meeting. 2009. https://doi.org/10.1115/fedsm2009-78492 [63] qi, x., n. turnquist, and f. ghasripoor, advanced electric submersible pump design tool for geothermal applications. 2012, ge global research. [64] zhu, j. and h.-q. zhang. cfd simulation of esp performance and bubble size estimation under gassy conditions. in spe annual technical conference and exhibition. 2014. onepetro. https://doi.org/10.2118/170727-ms [65] macaluso, c., discussion:“a review of slip factors for centrifugal impellers”(wiesner, fj, 1967, asme j. eng. power, 89, pp. 558–566). 1967. https://doi.org/10.1115/1.3616734 [66] sun, d. and m.j.j.p.v.t. prado, modeling gasliquid head performance of electrical submersible pumps. 2005. 127(1): p. 31-38. https://doi.org/10.1115/1.1845473 [67] thin, k.c., et al., design and performance analysis of centrifugal pump. 2008. 46(1): p. 422-429. [68] itō, h.j.j.o.b.e., friction factors for turbulent flow in curved pipes. 1959. 81(2): p. 123-132. https://doi.org/10.1115/1.4008390 [69] churchill, s.w. and c. sw, friction-factor equation spans all fluid-flow regimes. 1977. [70] ito¯, h. and k. nanbu, flow in rotating straight pipes of circular cross section. 1971. https://doi.org/10.1115/1.3425260 [71] bing, h., et al., prediction method of impeller performance and analysis of loss mechanism for mixed-flow pump. 2012. 55(7): p. 1988-1998. https://doi.org/10.1007/s11431-012-4867-9 https://doi.org/10.4177/001c.12372 http://www.portalabpg.org.br/bjpg/index.php/bjpg/article/view/107 http://www.portalabpg.org.br/bjpg/index.php/bjpg/article/view/107 http://www.portalabpg.org.br/bjpg/index.php/bjpg/article/view/107 http://www.portalabpg.org.br/bjpg/index.php/bjpg/article/view/107 http://www.portalabpg.org.br/bjpg/index.php/bjpg/article/view/107 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https://scholar.google.com/scholar?hl=en&as_sdt=0%2c5&q=%5b59%5d%09shojaeifard%2c+m.%2c+f.+boyaghchi%2c+and+m.+ehghaghi%2c+experimental+study+and+three-dimensional+numerical+flow+simulation+in+a+centrifugal+pump+when+handling+viscous+fluids.+2006.&btng= https://scholar.google.com/scholar?hl=en&as_sdt=0%2c5&q=%5b63%5d%09qi%2c+x.%2c+n.+turnquist%2c+and+f.+ghasripoor%2c+advanced+electric+submersible+pump+design+tool+for+geothermal+applications.+2012%2c+ge+global+research.&btng= https://scholar.google.com/scholar?hl=en&as_sdt=0%2c5&q=%5b63%5d%09qi%2c+x.%2c+n.+turnquist%2c+and+f.+ghasripoor%2c+advanced+electric+submersible+pump+design+tool+for+geothermal+applications.+2012%2c+ge+global+research.&btng= https://scholar.google.com/scholar?hl=en&as_sdt=0%2c5&q=%5b63%5d%09qi%2c+x.%2c+n.+turnquist%2c+and+f.+ghasripoor%2c+advanced+electric+submersible+pump+design+tool+for+geothermal+applications.+2012%2c+ge+global+research.&btng= https://scholar.google.com/scholar?hl=en&as_sdt=0%2c5&q=%5b63%5d%09qi%2c+x.%2c+n.+turnquist%2c+and+f.+ghasripoor%2c+advanced+electric+submersible+pump+design+tool+for+geothermal+applications.+2012%2c+ge+global+research.&btng= https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=e3510bae5253c090888ac43368b1a136c4b1d2b4 https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=e3510bae5253c090888ac43368b1a136c4b1d2b4 https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=e3510bae5253c090888ac43368b1a136c4b1d2b4 https://doi.org/10.1115/1.4008390 https://pascal-francis.inist.fr/vibad/index.php?action=getrecorddetail&idt=pascal7860099142 https://pascal-francis.inist.fr/vibad/index.php?action=getrecorddetail&idt=pascal7860099142 m. a. al-hejjaj et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 123 135 134 [72] amaral, g.d., single-phase flow modeling of an esp operating with viscous fluids. 2007, m. sc. thesis, state university of campinas, campinas, são paulo, brazil. [73] aungier, r.h., mean streamline aerodynamic performance analysis of centrifugal compressors. 1995. https://doi.org/10.1115/1.2835669 [74] tuzson, j., centrifugal pump design. 2000: john wiley & sons. [75] sun, d., & prado, m. (2006). single-phase model for electric submersible pump (esp) head performance. spe journal, 11(01), 80-88. 11(01): p. 80-88. https://doi.org/10.2118/80925pa [76] jones jr, o., an improvement in the calculation of turbulent friction in rectangular ducts. 1976. https://doi.org/10.1115/1.3448250 [77] shah, r., a correlation for laminar hydrodynamic entry length solutions for circular and noncircular ducts. 1978. https://doi.org/10.1115/1.3448626 [78] sun, d. and m. prado, modeling gas-liquid head performance of electrical submersible pumps. j. pressure vessel technol., 2005. 127(1): p. 3138. https://doi.org/10.1115/1.1845473 [79] ladouani, a. and a.j.f.i.i. nemdili, influence of reynolds number on net positive suction head of centrifugal pumps in relation to disc friction losses. 2009. 73(3): p. 173. https://doi.org/10.1007/s10010-009-0102-7 [80] van esch, b.p.m., simulation of threedimensional unsteady flow in hydraulic pumps. enschede, netherlands, 1997. [81] bates, r., et al., taking the pulse of producing wells—esp surveillance.". oilfield review, 2004. 16: p. 16-25. [82] castro, v., et al. esp application on heavy oil in peregrino field. in spe artificial lift conference—latin america and caribbean. 2015. onepetro. https://doi.org/10.2118/173948ms [83] takacs, g., how to improve poor system efficiencies of esp installations controlled by surface chokes. journal of petroleum exploration and production technology, 2011. 1(2): p. 8997. https://doi.org/10.1007/s13202-011-0011-9 [84] stanko, m. and m. golan. exploring the potential of model-based optimization in oil production gathering networks with espproduced, high water cut wells. in 17th international conference on multiphase production technology. 2015. onepetro. [85] stanko, m., et al. model-based production optimization of the rubiales field, colombia. in spe annual technical conference and exhibition. 2015. onepetro. https://doi.org/10.2118/174843-ms [86] al-jasmi, a., et al. esp "smart flow" integrates quality and control data for diagnostics and optimization in real time. in spe digital energy conference. 2013. https://doi.org/10.2118/163809-ms [87] adesanwo, m., et al. smart alarming for intelligent surveillance of electrical submersible pump systems. in spe annual technical conference and exhibition. 2017. https://doi.org/10.2118/187079-ms [88] shuwaikhat, h.a., et al. innovative approach to prolong esp run life using algorithmic models. in abu dhabi international petroleum exhibition & conference. 2017. onepetro. https://doi.org/10.2118/188807-ms [89] jansen van rensburg, n. ai4esp autonomous well surveillance for esp pumps using artificial intelligence. in spe oil and gas india conference and exhibition. 2019. https://doi.org/10.2118/194587-ms [90] jansen van rensburg, n., l. kamin, and s. davis. using machine learning-based predictive models to enable preventative maintenance and prevent esp downtime. in abu dhabi international petroleum exhibition & conference. 2019. https://doi.org/10.2118/197146-ms [91] sanusi, s., et al. estimation of bottom hole pressure in electrical submersible pump wells using machine learning technique. in spe nigeria annual international conference and exhibition. 2021. https://doi.org/10.2118/207122-ms [92] diker, g., h. frühbauer, and e.m. bisso bi mba. development of a digital esp performance monitoring system based on artificial intelligence. in abu dhabi international petroleum exhibition & conference. 2021. onepetro. https://doi.org/10.2118/207929-ms [93] bermudez, f., et al. an esp production optimization algorithm applied to unconventional wells. in abu dhabi international petroleum exhibition & conference. 2021. onepetro. https://doi.org/10.2118/207824-ms https://books.google.iq/books?hl=en&lr=&id=oyxacaomy8wc&oi=fnd&pg=pa3&dq=%5b74%5d%09tuzson,+j.,+centrifugal+pump+design.+2000:+john+wiley+%26+sons.&ots=fjoy5rspyp&sig=kc7gpzexczxwhvvrd-mab916qtu&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=oyxacaomy8wc&oi=fnd&pg=pa3&dq=%5b74%5d%09tuzson,+j.,+centrifugal+pump+design.+2000:+john+wiley+%26+sons.&ots=fjoy5rspyp&sig=kc7gpzexczxwhvvrd-mab916qtu&redir_esc=y#v=onepage&q&f=false https://www.researchgate.net/profile/bart-van-esch/publication/265247506_simulation_of_three-dimensional_unsteady_flow_in_hydraulic_pumps/links/54f991820cf2ccffe9e1834b/simulation-of-three-dimensional-unsteady-flow-in-hydraulic-pumps.pdf https://www.researchgate.net/profile/bart-van-esch/publication/265247506_simulation_of_three-dimensional_unsteady_flow_in_hydraulic_pumps/links/54f991820cf2ccffe9e1834b/simulation-of-three-dimensional-unsteady-flow-in-hydraulic-pumps.pdf https://www.researchgate.net/profile/bart-van-esch/publication/265247506_simulation_of_three-dimensional_unsteady_flow_in_hydraulic_pumps/links/54f991820cf2ccffe9e1834b/simulation-of-three-dimensional-unsteady-flow-in-hydraulic-pumps.pdf https://onepetro.org/bhricmpt/proceedings-abstract/bhr15/all-bhr15/bhr-2015-j2/322 https://onepetro.org/bhricmpt/proceedings-abstract/bhr15/all-bhr15/bhr-2015-j2/322 https://onepetro.org/bhricmpt/proceedings-abstract/bhr15/all-bhr15/bhr-2015-j2/322 https://onepetro.org/bhricmpt/proceedings-abstract/bhr15/all-bhr15/bhr-2015-j2/322 https://onepetro.org/bhricmpt/proceedings-abstract/bhr15/all-bhr15/bhr-2015-j2/322 https://onepetro.org/bhricmpt/proceedings-abstract/bhr15/all-bhr15/bhr-2015-j2/322 m. a. al-hejjaj et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 123 135 135 مراجعة التسلسل الزمني لتطوير المضخات الغاطسة الكهربائية 2، 1 عمر الفتالوي ، و 1 ضفاف جعفر صادق، ،*1 محمد عبدالكاظم مزهر الحجاج جامعة بغداد، بغداد، العراقكلية الهندسة، ، قسم هندسة النفط 1 ااسترالي ،غرب استراليا، جامعة كيرتن ،لمعادن والطاقة وهندسة الكيمياءمدرسة غرب استراليا للمناجم: ا 2 الخالصة ي من أبرز حلول الرفع االصطناعي ف ((espتعتبر المضخة الغاطسة الكهربائية الغاطسة المعروفة باسم ب نظًرا لكمية إنتاجها األكبر مقارنة بطرق الرفع االصطناعية األخرى حيث يعمل المرسا هندسة اإلنتاج؛ ين طرق تحسالكهروستاتيكي على زيادة االنتاج من خالل تحويل الطاقة الحركية إلى ضغط هيدروليكي للسائل. ل ، على سبيوالقيودف عدد كبير من الوظائ عقدة بسبب الحاجة إلى التعامل معم ادائية المضخة الغاطسة د ة والقيو مكونات المضخ ،عند الشفط، وتقييد التدفق الخارجي المثال: )تقييد التدفق الداخلي، وجزء فراغ الغاز رور طورت بمة ظهورها وكيف ت، من الضروري فهم كيفينظًرا ألهميتها وكفاءتها الكبيرةالكهربائية والميكانيكية(. espاجهتها في الصناعة النفطية. تقدم هذه الورقة مراجعة شاملة ألصل ، فضاًل عن التحديات التي و الوقت ، اطسةي أثرت على تطوير المضخة الغوالدراسات التطورية السابقة تضمنت مراجعة لجميع الدراسات السابقة الت جعة رابما في ذلك مكوناتها الكهربائية والميكانيكية ، وكذلك جميع مكونات قاع البئر والسطح. تم تقسيم م ات الدراسو ، أربعة أقسام: الدراسات التجريبية، ودراسات المحاكاة العددية، والنمذجة الميكانيكيةاألدبيات إلى المتعمقة حول تحسين اإلنتاج. .تحسين األنتاج ،ضخة كهربائية غاطسة، رفع اصطناعيم الكلمات الدالة: 1 iraqi journal of chemical and petroleum engineering vol.12 no.2 (june 2011) 1 8 issn: 1997-4884 correlation for solution gas -oil ratio of iraqi oils at pressures below the bubble point pressure omar f. hassan department of petroleum engineering-college of engineeringuniversity of baghdad abstract the solution gas-oil ratio is an important measurement in reservoir engineering calculations. the correlations are used when experimental pvt data from particular field are missing. additional advantages of the correlations are saving of cost and time. this paper proposes a correlation to calculate the solution gas -oil ratio at pressures below bubble point pressure. it was obtained by multiple linear regression analysis of pvt data collected from many iraqi fields. in this study, the solution gas-oil ratio was taken as a function of bubble point pressure, stock tank oil gravity, reservoir pressure, reservoir temperature and relative gas density. the construction of the new correlation is depending on thirty seven pvt reports that were collected from iraqi fields. statistical and graphical tools have been used to check the performance of the correlation. correlation performance was also compared with previous published correlations. the values of solution gas oil ratio that were calculated from the new correlation have high accuracy when they were compared with the original laboratory data. also, the results of the new correlation show high precision when compared with standing [1], vasquez and beggs [2], glaso [3], al-marhoun [4], petrosky and farshad [5], kartoatmodjo and schmidt [6], velarde, blasingame and mccain [7] and mazandarani and asghari [8] correlations. introduction solution gas-oil ratio, rs, is defined as the number of standard cubic feet of gas that dissolve in one stock-tank barrel of crude oil at certain pressure and temperature. the solubility of a natural gas in a crude oil is function of the pressure, the temperature, the api gravity and the gas gravity. for particular gas and crude oil to exist at a constant temperature, the solubility iraqi journal of chemical and petroleum engineering university of baghdad college of engineering correlation for solution gas –oil ratio of iraqi oils at pressures below the bubble point pressure vol.12 no.2 (june 2011) 2 increases with pressure until the saturation pressure is reached. at the saturation pressure, all the available gases are dissolved in the oil and the gas solubility attains its maximum value. a typical solution gas-oil ratio curve, as a function of pressure for an undersaturated crude oil, is shown in fig. 1. as the pressure is reduced from the initial reservoir pressure, pi, to the saturation pressure, pb, no gas evolves from the oil and consequently the gas solubility stills constant at its maximum value rsb. below the saturation pressure, the dissolved gas is liberated and the value of rs decreases with pressure. fig. 1 typical gas solubility/pressure relationship in the absence of experimentally measured solution gas-oil ratio of a crude oil system, it is necessary to determine this property from empirically derived correlations. published empirical equations many empirical correlations for estimating the solution gas-oil ratio are presented in this paper. these correlations covered oils from usa, north sea, middle east, gulf of mexico, iran and libya. further three correlations [2] [6] [7] of them depended on global data banks. standing [1] (1947) proposed a graphical correlation for determining the solution gas-oil ratio as a function of pressure, gas specific gravity, api gravity and system temperature. the correlation was developed from a total of 105 experimentally determined data points on 22 hydrocarbon mixtures from california crude oil and natural gases. standing [9] (1981) expressed his proposed graphical correlation in a mathematical form. vasquez and beggs [2] (1980) presented an improved empirical correlation for estimating rs. their correlation was obtained by regression analysis using more than five thousand measured solution gas-oil ratio data points. based on api gravity, the measured data were separated into groups. this division was made at a value of oil gravity of 30 o api. categorized that the value of the specific gravity of gas depends on the conditions under which it is separated from the oil, vasquez and beggs proposed that the value of specific gravity of gas as obtained from a separator pressure of 100 pisg is used in their correlation. this reference pressure was chosen because it represents the average field separator conditions. the authors proposed relationship for adjustment of the gas gravity to reference pressure. glaso [3] (1980) proposed a correlation for calculating the solution gas-oil ratio as a function of api gravity, the pressure, the temperature and the specific gravity of gas. the correlation was developed from studying a forty five samples obtained from north sea crude. marhoun [4] (1988) developed an expression for calculating the saturation pressure of middle eastern crude oil systems. the correlation was developed by using nonlinear multiple regression analysis and a trial and error method based on more than sixty different middle east crude oils. marhoun's correlation can be rearranged and solved for the solution gas-oil ratio. petrosky and farshad [5] (1993) developed new correlations for gulf of omar f. hassan 3 vol.12 no.2 (june 2011) mexico crudes. standing’s correlation for solution gas-oil ratio was taken as the basis for developing the new correlation coefficients. the approach that petrosky and farshad [5] applied to develop the correlation was to give the original correlation model maximum flexibility through nonlinear regression to achieve the best empirical relation possible with the available data set. the maximum flexibility allows each variable to have a multiplier and exponent, while the original model fixes multipliers and exponents of some of the variables to one. ninety data sets from the gulf of mexico were used in developing these correlations. kartoatmodjo and schmidt [6] (1994) used a global data bank to develop new correlations for all pvt properties. standing’s correlation was taken as the basis for solution gas-oil ratio correlation. in addition to the global data gathered for the study, a separate data set collected from the literature was used to verify the final results of the correlation models developed and compare them with published correlations. velarde, blasingame and mccain [7] (1999) formed new correlation to calculate the solution gas-oil ratio for pressures at and below saturation pressures. in contrast to many approaches presented in the past, this correlation of solution gas-oil ratio is not derived from rearranging a saturation pressure correlation. two sets of dimensionless functions were calculated with data from each pvt report. these functions are “reduced pressure” and “reduced gas-oilratio”. the reduced pressure variable is defined as the pressure divided by the bubble point pressure and the reduced gas-oil-ratio variable is defined as the solution gas-oil ratio divided by the solution gas-oil ratio at the bubble point. mazandarani and asghari [8] (2007) tuned al-marhoun 's [4] correlation to iranian field data to get modified correlation . they took about fifty fluid samples collected from different iranian fields. taghaz, eltaeb and alakhdar [10] (2008) tested the accuracy of pvt correlation to determine the solution gas-oil ratio of libyan oils using about 1600 data points from different reservoirs in the sirte basin. authors concluded that no correlation is suitable for libyan oils. experimental data experimental pvt data were collected from different oil reservoirs. thirty seven pvt reports that totally include four hundred data points represent the overall data of this paper. the ranges of data are listed in table 1. in addition, figs. 2, 3, 4 and 5 show the distribution details for reservoir temperature, gas relative density, bubble point pressure and oil gravity respectively. table 1 physical properties property minimum limit maximum limit api 20 37 t 190 275 γg 0.7 0.9 pb 1950 4000 (190,200] (270,280] (240,250] (230,240] (220,230] (210,220] (200,210] fig. 2 the distribution of reservoir temperature for overall data correlation for solution gas –oil ratio of iraqi oils at pressures below the bubble point pressure vol.12 no.2 (june 2011) 4 (0.72,0.74] (0.74,0.76] (0.76,0.78] (0.9,0.92] (0.88,0.9] (0.86,0.88] (0.84,0.86] (0.82,0.84] (0.8,0.82] (0.78,0.8] fig. 3 the distribution of relative gas density for overall data ( 1 8 0 0 ,2 0 0 0 ] ( 2 2 0 0 ,2 4 0 0 ] ( 2 4 0 0 ,2 6 0 0 ] ( 3 8 0 0 ,4 0 0 0 ] ( 3 4 0 0 ,3 6 0 0 ] ( 3 2 0 0 ,3 4 0 0 ] ( 3 0 0 0 ,3 2 0 0 ] ( 2 8 0 0 ,3 0 0 0 ] ( 2 6 0 0 ,2 8 0 0 ] fig. 4 the distribution of bubble point pressure for overall data <= 20 (20,22] (36,38] (30,32] (26,28] (24,26] (22,24] fig. 5 the distribution of oil gravity for overall data formulation of gas-oil ratio correlation the basic principle of formulation of a correlation is regression analysis that is defined as a conceptually simple method for investigating functional relationships among variables [11]. firstly, the regression analysis usually starts with a formulation of the problem by detection of the influent variables on gas-oil ratio. therefore the formulation of correlation includes the following properties: reservoir pressure, bubble point pressure, gas-oil ratio at bubble point pressure, oil gravity, gas specific gravity and the temperature of reservoir. the problem statement (formulation) is the first and possibly the most important step in regression analysis [11]. this step gave the following general relationship ……… (1) where the solution gas-oil ratio is the response variable and the set of predictor variables are the influent variables, while ε is assumed to be a random error representing the discrepancy in the approximation. secondly, many mathematical forms were suggested to formulate the correlation. they were subjected to nonlinear regression for detecting the true relationship between response variable and predictor variables. many statistical criteria were applied to select the optimum form of the correlation. finally, the filtration processes to produce the suitable correlation were achieved after the mathematical and graphical checking were finished. the following correlation is selected …. (2) where a0, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10 and a11 are the constants which are estimated by application of nonlinear regression. omar f. hassan 5 vol.12 no.2 (june 2011) the values of the constants are recorded in table 2. table 2 regression parameters regression parameter value a0 0.0006 a1 0.856 a2 0.351 a3 1.829 a4 1.462 a5 -2.116 a6 3.867 a7 -0.306 a8 -0.083 a9 -0.306 a10 -0.288 a11 0.525 validation of the correlation the solution gas-oil ratio curves resulting from the proposed method (eq. 2) have the correct profile. fig. 6 clarifies the results of the correlation compared with the same laboratory data for iraqi oil sample which was not used to achieve the new correlation. the agreement in both the shape of curves and the values is good. fig. 6 comparison of solution gas-oil ratios from new correlation with laboratory data the evaluation of the correlation's confidence has passed through two types of test that are statistical and graphically. all of experimental data were subjected to statistical tests that are absolute average error, standard deviation error, variance and sum of squared residuals. table 3 shows the results of statistical tests for the new correlation, standing [1], vasquez and beggs [2], glaso [3], al-marhoun [4], petrosky and farshad [5], kartoatmodjo and schmidt [6], velarde et al. [7] and mazandarani and asghari [8] correlations. these tests give the first kind of superiority to apply with iraqi oils because this correlation has the best statistical criteria among them. the statistical criteria explained that new correlation followed by velarde et al. [7] correlation. table 3 also showed that glaso [3] correlation and mazandarani and asghari [8] correlation have the highest error. correlation for solution gas –oil ratio of iraqi oils at pressures below the bubble point pressure vol.12 no.2 (june 2011) 6 table 3 statistical results the correlation average absolute error % sum of squared residuals standard deviation error variance new 5.04 168213.4 21.123 446.189 standing [1] 41.143 9681180 160.248 25679.52 vazquez and beggs [2] 42.554 11220114 172.515 29761.58 glaso [3] 47.226 14854317 198.498 39401.37 al-marhoun [4] 46.398 11591464 175.3471 30746.59 petrosky and farshad [5] 34.71 11199518 172.36 29706.94 kartoatmodjo and schmidt [6] 42.105 12004490 178.44 31842.15 velarde, blasingame and mccain [7] 10.156 428401.8 33.71 1136.344 mazandarani and asghari [8] 50.142 13595883 189.9035 36063.35 figs. 7 through 15 show the comparisons of the values of solution gas-oil ratio predicted by the correlations to that measured by experimental tests for the same sample which was not employed to complete the new correlation. new correlation gave better scattered around 45 o line as shown in fig. 7. mazandarani and asghari [8] correlation gave worst predicted values of solution gasoil ratio as shown in fig. 15. these cross plots completed the confidence of the new correlation because they explain that it has the highest matching with the experimental records. fig. 7 comparison of measured data and calculated solution gas-oil ratio by new correlation fig. 8 comparison of measured data and calculated solution gas-oil ratio by standing’s correlation fig. 9 comparison of measured data and calculated solution gas-oil ratio by vazquez and beggs's correlation omar f. hassan 7 vol.12 no.2 (june 2011) fig. 10 comparison of measured data and calculated solution gas-oil ratio by glaso's correlation fig. 11 comparison of measured data and calculated solution gas-oil ratio by almarhoun's correlation fig. 12 comparison of measured data and calculated solution gas-oil ratio by petrosky and farshad 's correlation fig. 13 comparison of measured data and calculated solution gas-oil ratio by kartoatmodjo and schmidt 's correlation fig. 14 comparison of measured data and calculated solution gas-oil ratio by velarde et al. correlation fig. 15 comparison of measured data and calculated solution gas-oil ratio by mazandarani and asghari's correlation correlation for solution gas –oil ratio of iraqi oils at pressures below the bubble point pressure vol.12 no.2 (june 2011) 8 conclusions the new correlation is accurate, flexible and reliable tool for calculating solution gasoil ratio for iraqi oils at pressures below bubble point pressure for the range of data that have been illustrated in this paper. nomenclature api: api gravity pvt: pressure-volume-temperature p: pressure, psi rs : solution gas-oil ratio, scf/stb rsb : solution gas-oil ratio at bubble point pressure, scf/stb t : reservoir temperature, o f γg : specific gravity of gas γo : specific gravity of oil ε : random error, scf / stb references 1. standing, m. b., (1947), "a pressurevolume-temperature correlation for mixtures of california oil and gases", drilling & prod. prac, api. 2. vasquez, m. e. and beggs, h. d., (june 1980), “correlations for fluid physical property prediction,” jpt, 968-70. 3. glaso, o., (may 1980), “generalized pressure-volume-temperature correlations”, jpt, 785-95. 4. a1-marhoun, m. a., (may 1988), “pvt correlations for middle east crude oils”, jpt, 650-666. 5. petrosky, g. e. and farshad, f. f., (1993), “pressure – volume temperature correlations for gulf of mexico crude oils”, paper spe 26644. 6. kartoatmodjo, t. and schmidt, z., (july 1994), “large data bank improves crude physical property correlations”, oil & gas journal. 7. velarde, j. j., blasingame, t.a., and mccain, w. d., jr., ( june 1997), “correlation of black oil properties at pressures below bubble point pressure a new approach”, paper 97-93 presented at the 48th atm of the petroleum society, calgary. 8. mazandarani, m. t. and asghari, s. m., (september 2007), “correlations for predicting solution gas-oil ratio, bubblepoint pressure and oil formation volume factor at bubblepoint of iran crude oils”, european congress of chemical engineering, copenhagen... 9. standing, m. b., (1981), “volumetric and phase behavior of oil field hydrocarbon systems”, 9 th edition dallas: society of petroleum engineers. 10. taghaz a., eltaeb n. and alakhdar s., (2008) “comparison study of published pvt correlations and its application to estimate reservoir fluid properties for libyan oil reservoirs”, paper presented at the tenth mediterranean petroleum conference and exhibition, libya. 11. chattefuee s., (2006) “regression analysis by example”, a john wiley & sons, inc., hoboken, new jersey. iraqi journal of chemical and petroleum engineering vol.17 no.2 (june 2016) 714 issn: 1997-4884 entransy dissipation of shell and double concentric tubes heat exchanger basma abbas abdulmajeed and zena fallah abdulah university of baghdad, college of engineering, department of chemical engineering abstract the concept of entransy dissipation was determined for new type of heat exchanger (shell and double concentric tubes heat exchanger). three parameters, hot oil flow rate, temperature of inlet hot oil and pressure drop of system were investigated with this concept (entransy dissipation). the results showed that the value of entransy dissipation of oil and of system which represents the summation of entransy dissipation of both oil and water increased with increasing the flow rate of hot oil and these values were larger when cold water flow rate was doubled. also they were increased with increasing the hot oil inlet temperature at a certain flow rate of hot oil. furthermore, the pressure drops for hot oil in both shell side and inner tubes side was constant and increased according to the increase of its flow rate. at different hot oil flow rate and a certain hot oil inlet temperature, the entransy of hot oil was increased with its pressure drop. in order to keep up with modern technology, infrared thermography camera was used in order to measure the temperatures which were higher than the temperatures obtained by thermocouples. for that reason the entransy dissipation was determined with lower values compared with their values obtained by using thermocouples. key words: entransy, entransy dissipation, heat exchangers, concentric tubes introduction in the last few years, heat transfer optimization was based on the concept of entransy. the concept of entransy was proposed by the analogy between electrical conduction and heat conduction [1]. according to this analogy the electric current is compatible with heat flow, electrical resistance with the thermal resistance, electric voltage with the temperature and capacitance with the heat capacity. so, the potential energy of the heat stored in a body was defined as entransy, and it complies with the electrical energy in a capacitor [2]. in this sense, the electricity conduction will be obtained if there is a difference of potential voltage also heat conduction will be obtained if there is a difference of temperature. many studies usually use this analogy in complex systems to facilitate the study of steady state or unsteady state heat conduction problems [3]. comparable to the electric energy when transported accompanied to the electric charge during electric conduction, entransy is transported along with the heat during heat iraqi journal of chemical and petroleum engineering university of baghdad college of engineering entransy dissipation of shell and double concentric tubes heat exchanger 8 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net transfer. for this reason entransy will be reduced and some of entransy is dissipated during the heat transport when a quantity of heat is transferred from a high temperature to a low temperature. so entransy dissipation can be defined as the lost entransy which is dissipated during the heat transfer and it is an evaluation of the irreversibility of heat transport ability [4]. also according to the second law of thermodynamics, the entransy dissipation represents the energy dissipated from the object of high temperature to the object of low temperature [2, 5 and 6]. one of the most important and widely used devices in the human life and industry which is used to transfer thermal energy between fluids is the heat exchanger. so, it is necessary to look for new ways for optimization of heat exchanger by maximizing their performance for heat transfer and reduce the cost of energy used. in this sense many studies have been done investigating entransy dissipation and/or entropy generation to represent the optimum performance of heat exchanger. in two streams single pass heat exchanger as shown in figure 1; entransy dissipation was studied by qian and li [7]. they derived the equation of entransy dissipation based on the energy balance equation for the heat exchanger as shown in the equation below: ( ) ( ) … (1) qian and li [7] showed that the entransy dissipation in heat exchanger does not depend on the flow arrangement and it can be calculated by the inlet and outlet temperatures, and it is applicable for all types of flow arrangements even though it is derived for a single-pass heat exchanger. fig. 1, two streams single pass heat exchanger [7]. also optimization of heat transfer processes by entransy and entransy dissipation was done by zhu and guo [8] and guo and chen [9]. furthermore, they considered that the measures of loss the ability to heat transfer is by the entransy dissipation. in the same manner, the loss of ability to produce work is relative to entropy generation. so problem in materials of high thermal conductivity related to temperature distribution were analyzed and optimized by using these concepts. also chen et al. [10] used the concept of entransy to examine a problem of heat conduction by determining the optimal distribution of a material of high thermal conductivity in a given volume. other authors like wu and liang [11] utilized entransy and entransy dissipation in the heat transfer by radiation. they deduced that, as a result of irreversibility, entransy was slightly dissipated during the processes of heat transfer by radiation. also a problem between three bodies during the heat transfer by radiation was optimized by using the extreme principle of entransy dissipation. the main goal of this research is to study the entransy dissipation which is to be studied and investigated using a new type of heat exchanger that differs from the conventional one consisting of double bundles of tubes instead of one bundle called the shell and double concentric tubes heat exchanger. behavior of entransy dissipation will be studied through different parameters such as flow rate of inlet hot oil, temperature of inlet hot oil, pressure basma abbas abdulmajeed and zena fallah abdulah -available online at: www.iasj.net ijcpe vol.17 no.2 (june 2016) 9 drop of both hot oil and cold water and flow rate of inlet cold water. experimental work 1heat exchanger description the shelland -double concentric tubes heat exchanger was used instead of the conventional one, where the tubes were replaced by double concentric tubes as in figure 2. this will improve the heat transfer through an additional flow passage which gives larger heat transfer area. the hot oil flows though the shell and the inner tubes sides while the cold water flow through the annulus side. fig. 2, shelland -double concentric tube heat exchanger. (a) conventional one (b) modified one. 2description for the parts of the unit a tank of 250 liters was used as a supplier for the cold water, which is pumped by single stage centrifugal pump passing through a flow meter to measure its flow rate. the outlet cooling water was collected in a vessel of 100 liters to measure its temperature using a portable thermocouple, where the water was drained to the sewage. on the other side, a cubical tank (reheater tank) supplied with two electrical heaters was used to heat the oil to the desired temperature controlled by thermostats and measured by thermocouple. a centrifugal pump was used to pump the hot oil through the flow meter where the flow was controlled by gate valves. the outlet hot oil leaving the heat exchanger was collected in a 200 liters tank where the temperature was measured using a thermocouple. six pressure gauges were used to measure the pressure for the fluids streams. two pressure gauges were used for the inlet and outlet streams of cold water, the other four gauges were used for the inlet and outlet streams of hot oil, two of them for hot oil flow through the shell and the others for the hot oil flow through the inner tubes. figure 3 illustrate the schematic diagram of operating system unit. fig. 3, schematic diagram of operating system unit entransy dissipation of shell and double concentric tubes heat exchanger 10 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net 3experimental procedure the two heaters were switched on for heating oil to the required temperature (50, 60, 70 and 80c). after that the hot oil was pumped to the shell side and the inner tubes side in the heat exchanger after controlling the flow rate to its desired value (15, 25, 35 and 45 l/min.). the cold water was pumped in the annuals side at the same time with the hot oil to the desired flow rate (20 and 40 l/min.). at steady state, the temperatures and pressures were constantly measured during the flow rate variation. the results were analyzed for the different conditions. infrared thermography camera (thermo gear g100ex/g120ex) was used to measure the temperatures of fluids in the system (figure 4). the results obtained from the infrared thermography camera were analyzed and compared with the results obtained by using thermocouples. fig. 4, infrared thermography camera (thermo gear g100ex/g120ex) [12] results and discussions parameters effect on entransy dissipation in heat exchanger 1effects of heated oil flow rate entransy dissipation of oil with different oil flow rate at different oil inlet temperatures (50, 60, 70, and 80c) are shown in the figure 5. it can be seen from figure that entransy dissipation of oil increases with increasing the flow rates of hot oil (15, 25, 35, and 45 l/min.). this is correct since the entransy dissipation represent the energy dissipated from the hot oil of high temperature to the cold water of low temperature [2, 5 and 6]. so by increasing the flow rate of hot oil, an increase in the dissipation of energy is obvious. 2effects of heated oil inlet temperatures entransy dissipation at different temperatures of inlet hot oil which changed from 50, 60, 70 and 80c were investigated for each hot oil flow rates 15, 25, 35 and 45 l/min as seen in figure 6. figure show that entransy dissipation of oil increases with increasing temperature at a certain flow rate of oil. that is to say, the higher the hot oil inlet temperature is, the higher the energy dissipated will be [6]. this is compatible with guo et al. [1] that heat transfer is an irreversible process and the entransy dissipation occurs since the entransy is not conserved and the temperature difference is finite [3]. fig. 5, comparing entransy dissipation of oil with hot oil flow rate at different oil inlet temperatures, water flow rate 20 l/min. basma abbas abdulmajeed and zena fallah abdulah -available online at: www.iasj.net ijcpe vol.17 no.2 (june 2016) 11 fig. 6, entransy dissipation of oil at different temperatures of inlet hot oil (50, 60, 70 and 80c) at different hot oil flow rates (15, 25, 35 and 45 l/min) and water flow rate 20 l/min. 3effects of heated oil pressure drop in the heat exchanger there are two kinds of irreversibility, one comes from the temperature finite differences causing heat conduction and the other comes from the finite pressure drops causing flow friction [5]. the experimental results shows that the pressure drops in each shell side, inner tubes side and annulus side are constant for a specified hot oil flow rate and at any hot oil inlet temperatures. the entransy dissipation of oil with pressure drop at different hot oil inlet temperatures (50, 60, 70, and 80c) are shown in figures 7. curves in the figure show that at a certain hot oil inlet temperature, the entransy dissipation of oil increased with the pressure drop at different hot oil inlet flow rates (15, 25, 35, and 45 l/min), but there is no different in the value of the pressure drop at a certain inlet hot oil flow rate. fig. 7, comparison between entransy dissipation of oil with pressure drop at different hot oil inlet temperatures (50, 60, 70, and 80c). water flow rate is 20 l/min. 4effects of cold water flow rate experiments were done by doubling the flow rate of cold water (40l/min) to investigate the effects of cold water flow rate on the values of entransy dissipation. the results of entransy dissipated from shell and inner tubes of heat exchanger for different oil inlet flow rates at a certain hot oil temperature or different hot oil temperatures at a certain oil flow rate for both 20 and 40 l/min cold water flow rates are illustrated in figure 8 and figure 9 respectively. figures show that the entransy dissipation of oil was increased but with a larger values when 40 l/min of cold water was used. so when the flow rate of cold water increasing, the dissipation of energy increases, leading to increase in the entransy dissipation. infrared thermography camera results to keep up with development in the use of modern techniques and devices, an infrared thermography camera has been used to obtain the temperatures of hot oil and compare these results with the results that were obtained when using the conventional thermocouples. entransy dissipation of shell and double concentric tubes heat exchanger 12 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net the comparison between the entransy dissipation obtained using the data of outlet oil temperatures determine by different techniques are shown in figure 10. it was noticed from figure 10 that the entransy dissipation calculated from using infrared camera in some points was less than the entransy dissipation calculated from using thermostat. this is because the values of outlet oil temperature obtained by infrared camera in some points are higher than these temperatures obtained by thermostat at a certain oil flow rate. so the values of temperature finite difference which are used to calculate the entransy dissipation will be lower. fig. 8, comparison between the entransy dissipated from shell and inner tubes of heat exchanger for different oil inlet flow rates at a certain hot oil temperature for both 20 and 40 l/min cold water flow rates. the dotted lines represent the entransy at 20 l/min cold water flow rate. fig. 9, comparison between the entransy dissipated from shell and inner tubes of heat exchanger for different hot oil inlet temperatures at a certain hot oil flow rate for both 20 and 40 l/min cold water flow rates. the dotted lines represent the entransy at 20 l/min cold water flow rate. basma abbas abdulmajeed and zena fallah abdulah -available online at: www.iasj.net ijcpe vol.17 no.2 (june 2016) 13 fig. 10, comparison the entransy dissipation obtained using the data of outlet oil temperatures determine by different techniques. the dotted curves represent the entransy obtained using thermostat. cold water flow rate 20 l/min. conclusions the concept of entransy dissipation was determined for a new type of heat exchanger (shell and double concentric tubes heat exchanger). the relation between entransy dissipation and parameters of hot oil flow rate, temperature of inlet hot oil and pressure drop of system were investigated and the results showed that the entransy dissipation of oil increases with increasing the flow rate of hot oil. also entransy dissipation of oil increased with increasing the hot oil inlet temperature at a certain flow rate of hot oil. furthermore, the pressure drops in each shell side, inner tubes side and annulus side are constant for a specified hot oil flow rate and at any hot oil inlet temperatures. at different hot oil flow rate and a certain hot oil inlet temperature, the entransy dissipation of hot oil increases with its pressure drop. on the other hand, entransy dissipation of oil increased with increasing the flow rate of hot oil when cold water flow rate was doubled and the values of entransy dissipation are higher. finally, the entransy dissipation was determined with lower values when infrared thermography camera was used to measure the temperatures, compared with their values obtained by using thermocouples. nomenclatures symbols description units g entransy dissipation w.k cc heat capacity rate of cold stream w.k -1 ch heat capacity rate of hot stream w.k -1 tc,i & tc,o inlet and outlet temperatures of cold stream k th,i & th,o inlet and outlet temperatures of hot stream k references 1guo z. y., zhu h. y., liang x. g. (2007) “entransya physical quantity describing heat transfer ability”, int. j. heat mass transfer, 50:2545-2556. 2cheng x. t., liang x. g. (2013) “discussion on the entransy expressions of the thermodynamic laws and their applications”, energy, 56: 46-51. entransy dissipation of shell and double concentric tubes heat exchanger 14 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net 3oliveira s. r., and milanez l. f., (2010) “the concept of entransy and its utilization in the analysis of problems in thermodynamics and heat transfer”, 13th brazilian congress of thermal sciences and engineering, uberlandia, mg, brazil, 05-10. 4chen q., liang x. g., guo z. y., (2011) “entransy a novel theory in heat transfer analysis and optimization, developments in heat transfer”, dr. marco aurelio dos santos bernardes (ed.), isbn: 978-953-307-569-3. 5puranik s. and joshi a. (2013) “experimental analysis of entransy dissipation number as performance parameter for heat exchanger”, international journal of mechanical engineering and research, issn no. 2249-0019, volume 3, number 4, pp. 309-316. 6kim k. h. and kim s. w., (2015) “entransy dissipation analysis for optimal design of heat exchangers”, journal of automation and control engineering vol. 3, no. 2. 7qian x. d., li z. x. (2011) “analysis of entransy dissipation in heat exchangers”, int. j. thermal sci. 50: 608-614. 8zhu, h. y. and guo, z. y. (2007) “entransy dissipation analysis and heat transfer optimization”, proceedings of the 18th international symposium on transport phenomena, daejeon, korea, pp. 389-393. 9guo, z. y. and chen, q. (2007) “irreversibility and optimization of transfer processes”, proceedings of the 18th international symposium on transport phenomena, daejeon, korea, pp. 22-32. 10chen l., wei s. and sun f., (2008) “constructal entransy dissipation minimization for „volume-point‟ heat conduction”, journal of physics d: applied physics, vol.41, pp. 1-10. 11wu, j. and liang x. (2008) “application of entransy dissipation extremum principle in radiative heat transfer optimization”, science in china series e: technological sciences, vol.51, pp. 1-9. 12http://www.infrared.avio.co.jp/en/p roducts/ ir-thermo/whatthermo.html. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.20 no.4 (december 2019) 55 – 60 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: israa sabah, email: sabah.israa@yahoo.com, name: abeer i. alwared, email: dr.abeer.wared@coeng.uobadghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. adsorption of congo red dye from aqueous solution onto wheat husk in a fluidized bed reactor israa sabah a and abeer i. alwared b a ministry of water resources b environmental eng. department, university of baghdad abstract the purpose of this paper is to examine absorbance for the removal of the red congo using wheat husk as a biological pesticide. several experiments have been conducted with the aim of configuring breakthrough data in a fluidized bed reactor. the minimum fluidized velocities of the bed were found to be 0.031 mm/s for mish sizes of (250) µm diameter with study the mass transfer be calculated kl values. the results showed a well-fitting with the experimental data. different operating conditions were selected: bed height (2, 5 and 10) cm, flow rate (09, 100and 120) ml/sec and particle diameter (250, 600, 1000) µm. the breakthrough curves were plotted for congo red, values showed that the lower the bed, the lower the number of adsorbents and the potential of the weak bed to condense the density of the solution, which also increases the flow rate and will increase the mass transfer rate. keywords: congo red dye, wheat husk, continuous experiments, mass transfer, breakthrough received on 03/03/2019, accepted on 20/04/2019, published on 30/12/1929 https://doi.org/10.31699/ijcpe.2019.4.9 1introduction dyes are one of the types of organic compounds that have the ability to provide a bright color that lasts for various materials [1]. more than 100,000 paints are available for commercial uses, which are specially formulated to be highly resistant to fading when exposed to sweat, light, water and oxidizing agents, and are thus highly stable and difficult to analyze.[2]. synthetic dyes have many uses, especially in textiles, leather, paper, rubber, plastic, cosmetics, pharmaceuticals and food industries. often "these complex aromatic molecular structures make them more stable and have low biodegradability [1; 3]. azo dyes have many uses and are widely used by different industries. some of the dyes used for industrial coloring paints are thrown into the environment. cr is toxic to many organisms and is a suspected carcinogen and mutagen. the colored wastewater in the water bodies is not only unpopular but negatively affects aesthetics as well as prevents light entering and reduces photosynthesis. there are many dyes that have toxic, carcinogenic, mutagenic and teratogenic effects on aquatic life and humans.[4]. therefore, the process of removing dyes from wastewater is important to prevent environmental pollution on an ongoing basis. there are different types of biological and physical/ chemical treatment methods for the disposal of pigments found in liquid industrial wastes, such as coagulation, membrane separation, electrochemical oxidation, ion exchange, and adsorption. among these methods, adsorption is currently considered to be the best treatment potential in general and has proved to be an efficient and economical process to remove dyes using different mazes.[5]. much attention has been focused on studying different types of low-cost materials such as sub-agricultural products, which are arbitrarily removed or burned, resulting in loss of resources and environmental damage.[6], such as coconut husk, wheat straw, corncobs, and barley husks. fixed and fluidized beds have been used widely by chemical industry, pharmaceutical industry, food industry, wastewater treatment and recovery of different substance [7]. fbr reactor, a type of reactor device used to operate different types of chemical reactions. in this type of reactor, it enters the liquid (gas or liquid) through a granular material (usually the catalyst in the form of small balls) and quickly enough to work on lifting the particles and treating them as if they were liquid. this provides vulnerable families with adequate space. there is no contact between the particles and the intimate contact of the entire surface with the polluted current, making the process faster by increasing the adsorption surface area of the adsorbents by reducing the dead areas between the particles [8]. basis of adsorption and fluidized bed reactor can be considered common and important reactors in process engineering due to the good mass and heat transfer rate between liquid and particles, between particles and the side wall of columns[9]. https://doi.org/10.31699/ijcpe.2019.4.9 i. s. and a. i. alwared / iraqi journal of chemical and petroleum engineering 20,4 (2019) 55 60 65 it is possible to expect that the bed with the activated carbon has shown an increase in the efficiency of removing some pollutants in the wastewater compared to the fixed bed under the same working conditions[10]. the aim of this work was to study the influenced of some parameters that have an effect on the behavior of liquid fluidized bed for the removal of cr dye from wastewater using wheat husk, other studies were performed in fluidized bed reacter [11; 12] and in adsorption [13] 2experimental work 2.1. adsorbent material wheat husk (wh) is an organic sorbent that has been collected from one of the wheat fields in wasit province. the removal of foreign objects was done by hand and was then washed several times with tap water and then with distilled water to make sure dirt is removed. the material was washes and then tapped to reach the desired size of the grain. after that, it was dried for 2 hours in an oven preserved at 125 ° c, then allowed to cool to laboratory temperature and then kept in closed glass containers until being used, fig. 1. fig. 1. wheat husk (wh) before and after grinding table 1. physical properties of wheat husk item name granular wheat husk base w.h. bulk density 334.56 kg/m3 particle density (1502.6) kg/m3 surface area 0.8329 m2/g internal porosity 0.777 2.2. adsorbate material congo red (cr) is one of the most commonly used materials for the dying of cotton, wood, silk and is considered a chemical compounds heterogeneous cycle (c32h22n6o6s2na2; molecular weight 696.68) as molecular formula and a molecular weight. a stock solution of 1000 mg/l of cr dye was prepared for calibration purposes. from the stock, different concentrations of cr were prepared by diluting with water. ph, and concentration mg/l were kept constant 6.7 and 25 m\l, respectively. the various chemicals used in this study are considered analytical. the process of preparation of the artificial wastewater used in this experiment contains the required amount of dye by dissolving the calculated amount of the cr dye in the distilled water. the concentration of the dye was subsequently determined using spectrophotometer (advanced microprocessor uv-vis spectrophotometer single beam li-295) at the predetermined maximum absorbance wavelength (λmax=497nm) of the cr dye for different concentrations of cr subsequently. 2.3. fluidized bed experiments the experimental setup consists of a fluidized film; fluidized bed reactor having an effective volume of 0.0024m 3 . the specification of the experimental set up is given in table 2 and schematic diagram is shown in fig. 2. table 2. physical features and process parameters s.no. specifications details 1 effective volume of reactor 0.0024 m 3 2 diameter of reactor 0.05m 3 height of reactor 1.2m 4 height of fluidized bed before fluidization 3 nos. 5 flow distributer 3 nos. 6 particle size of wheat husk 3 nos. fig. 2. experimental model of fluidized bed reactor 3results and discussion 3.1. estimation of the minimum fluidization velocity the work to determine the minimum dilution rate (umf) is piloted by calculating the low pressure across the layer of wheat straw particles. one particle size was used in these study (250) micrometers. the column was partially filled with particles from the known mass and then mixed strongly with water to arrange the particles and break any internal structure, then left the bed to settle down. i. s. and a. i. alwared / iraqi journal of chemical and petroleum engineering 20,4 (2019) 55 60 65 after which, the flow rate gradually increased from 0 to 120 ml / sec using the flowmeter. as each flow rate increase, pressure reduction was recorded using a pressure gauge. fig. 3 shows the pressure drops across the bed against the superficial fluid velocity in scale. the graph is used to read the minimum fluidization velocity (umf). the umf can be read from the sharp change in the pressure drop over the fluidized bed region. the low pilot fluid velocity is roughly equal to theoretical velocity. therefore, the lower flow using the continuous experiments is equal to 80 ml / min. different flow figures greater than the minimum flow rate were used for the purpose of increasing contact and its impact on the efficiency of cr removal. theoretically, minimum fluidized velocity value calculated using equation (1) and it was equal to 0.031 m/s (minimum flow rate = 88 ml/sec). 𝑈𝑚𝑓=𝜇/𝑑p.𝜌𝑙𝑅𝑒 (1)[14] where: umf is the minimum fluidized velocity. dp is the particle diameter, ρl is the density of liquid and μ is the liquid viscosity(water =1×10 -3 ). fig. 3. pressure drop vs. superficial fluidized flow rat in wheat husk bed of 250 µm particles diameter 3.2. estimation of mass transfer in fluidized bed reactor. fluidized bed reactor offers high available surface area, since there is no contact between particles. this development depends on the balanced data of the different velocity continuous flow fluidized-bed system. the correlations used in this study were listed in eq. (2). these correlations were developed in a fixed and fluidized bed system. the calculated kl values using these correlations were listed in table (3)." the high flow rate leads to a cycle of reynolds, which results in a higher sherwood number. the number of sherwood is directly proportional to the coefficient of the material carrier, so the high number of sherwood works to increase the coefficient of the material carrier and the overall mass transfer rate"[14]. it is expected that the change in flow rate will affect the film diffusion but not the intra-particle diffusion. the higher the flow rate the smaller the film resistance to mass transfer and larger kl values. sh=0.35 re 0.6 sc 1/3 (2) [15] dm=2.74∗10 −9 (mw) −1/3 (3)[16] in which the schmidt number (sc =ν/dm) is calculated using the liquid kinematic viscosity, ν (m 2 /s), and the liquid phase diffusivity, dm (m 2 /s). several methods may be used to calculate the liquid phase diffusivity, one of the most widely used [17]. table 3. calculated kl values of cr at different flow rate wh flow rate (ml/sec) sh, (kl.d/dm) kl*10 5 (m/s) cr 80 214.9 27.2 100 245.8 31.1 120 274.2 34.6 3.3. breakthrough curves the breakthrough curves for cr dye solution were obtained by plotting c/co versus time at different operating conditions. the concentration of the primary dye varies, as well as the height of the bed, the flow rate of cr absorption on the studied bed and the removal efficiency in the fluid system. a. effect of adsorbent bed height fig. 4 shows the breakthrough curves obtained for cr adsorption on the wheat husk for three different bed heights of (2, 5 and 10) cm, at a constant flow rate of 100 ml/sec. this figure shows that increasing of bed height will increase the adsorption capacity; in addition to that, the increase in bed height gives the time to connect these molecules to condense on the absorbing surfaces, suggesting that at the height of the low bed, the density of the effluent increases more rapidly than the height of the upper bed. also, in a low bed, the bed is saturated at less time. the height of the low bed corresponds to a small amount of adsorbents and a weak capacity for the bed to condense the density of the solution. when the flow rate remains constant, increasing the height of the bed will increase the time of solubility in the bed, improving the solvent removal efficiency. these results are consistent with those obtained before (17; 18). 0 500 1000 1500 2000 2500 3000 3500 4000 4500 0 50 100 150 ▲ p flow rate ,ml/sec i. s. and a. i. alwared / iraqi journal of chemical and petroleum engineering 20,4 (2019) 55 60 65 fig. 4. the experimental breakthrough data for adsorption of c.r. onto wheat husk at different bed depths, q=100 ml/sec, co=25.0 mg/l, ph=6.7, d=250µm b. effect of the solution flow rate in this part of the work, flow rate and cr adsorption using wheat husk were studied using different sprays (80, 100 and 120) ml / sec, with a fixed height bed of 0.05 m, as shown in the penetration curves in fig. 5. the higher the flow rate, the higher the penetration curves. the downtime is less time remaining in the column than the few. because of the increased flow rate, the suction solution leaves the column before reaching full equilibrium because the contact time is short. the higher the flow rate, the smaller the thickness of the surface layer which is considered to be resistant to mass transport. increasing the flow rate will increase the mass transfer rate. increasing the flow rate leads to a connection (mixing) which makes penetration and passage of adsorbed particles through the molecules that occupy the site (s) on the adsorbent easier. this is because there is sufficient contact time that affects the amount of capacitance. the few flow rates that will have enough contact time to occupy the space within the particles, this result is consistent with that obtained previously (17; 18). fig. 5. the experimental breakthrough data for adsorption of cr onto wheat husk at different flow rates, l=5 cm, co=25 mg/l, ph=6.7, d=250µm c. effect of particle size different particle size of wh (250, 600, 1000) µm were used for the removal of congo red from aqueous solution at constant flow rate (100) ml/sec in wh, and dyes concentration (25) mg/l , bed height (5)cm as shown in fig. 6. the results indicate that the shape shows well the penetration curves, and increases with the size of the lower particles. this indicates that the particles of exact size have outer transfer surface areas that are more effective than largesize particles with the same mass as wh. film diffusion is the basic rate mechanism for smaller particles that quickly reach saturation[19]. fig. 6. the experimental breakthrough data for adsorption of cr onto wheat husk at different particles size, l=5 cm, co=25 mg/l, ph=6.7 4conclusion the purpose of the study was to remove cr from wastewater using wheat husk as an adsorbent in a fluidized bed reactor. the curves showed a breakthrough for cr that breaks the time better compared to others. this can be attributed to the largest electronegativity value compared with others. in fluidized bed system, the minimum fluidized velocities of bed were found to be 0.031 m/s, an increase in the bed height of wheat husk will increase the breakthrough time. a decrease in the particle size will increase surface area of adsorption. an increase in the discharge reduces the penetration time led to the reduction in the contact between absorbent with absorbent material. also, that the flow rate decreases, the dye has enough time to fill out the areas within the particles. furthermore, increasing the particle size leads to a reduction at the time of the cutting point due to the surface area of the large particles being weaker than the small particles. i. s. and a. i. alwared / iraqi journal of chemical and petroleum engineering 20,4 (2019) 55 60 65 references [1] r. gong, y. sun, j. chen, h. liu, and c. yang,2005 “effect of chemical modification on dye adsorption capacity of peanut hull,” dye. pigment., vol. 67, no. 3, pp. 175–181. [2] p. nigam, g. armour, i. m. banat, d. singh, and r. marchant,2000 “physical removal of textile dyes from effluents and solid-state fermentation of dye-adsorbed agricultural residues,” bioresour. technol., vol. 72, no. 3, pp. 219–226. [3] v. s. mane, i. d. mall, and v. c. srivastava, 2007“use of bagasse fly ash as an adsorbent for the removal of brilliant green dye from aqueous solution,” dye. pigment., vol. 73, no. 3, pp. 269–278. [4] r. gong, y. jin, j. chen, y. hu, and j. sun,2007 “removal of basic dyes from aqueous solution by sorption on phosphoric acid modified rice straw,” dye. pigment., vol. 73, no. 3, pp. 332–337. [5] o. j. hao, h. kim, and p.-c. chiang,2000 “decolorization of wastewater,” crit. rev. environ. sci. technol., vol. 30, no. 4, pp. 449–505. [6] s. y. wong, y. p. tan, a. h. abdullah, and s. t. ong,2009 “the removal of basic and reactive dyes using quartenised sugar cane bagasse,” j. phys. sci., vol. 20, no. 1, pp. 59–74. [7] y. g. park, s. y. cho, s. j. kim, b. g. lee, b. h. kim, and s.-j. park,1999 “mass transfer in semifluidized and fluidized ion-exchange beds,” environ. eng. res., vol. 4, no. 2, pp. 71–80. [8] c. arnaiz, p. buffiere, s. elmaleh, j. lebrato, and r. moletta,2003 “anaerobic digestion of dairy wastewater by inverse fluidization: the inverse fluidized bed and the inverse turbulent bed reactors,” environ. technol., vol. 24, no. 11, pp. 1431–1443. [9] y. fu and d. liu,2007 “novel experimental phenomena of fine-particle fluidized beds,” exp. therm. fluid sci., vol. 32, no. 1, pp. 341–344. [10] j. s. jeris, c. beer, and j. a. mueller,1974 “high rate biological denitrification using a granular fluidized bed,” j. (water pollut. control fed., pp. 2118–2128. [11] a.k. mohammed, a. h., ghassan yousuf, r., & khalifa esgair, k. (2011). cracking activity of prepared y-zeolite catalyst using cumene on fluidized bed reactor. iraqi journal of chemical and petroleum engineering, 12(2), 9-17. [12] a. h. a-k mohammed and k. khalifa esgair, “fluid catalytic cracking of petroleum fraction (vacuum gas oil) to produce gasoline”, ijcpe, vol. 11, no. 4, pp. 33-45, dec. 2010. [13] h. adil sabbar, “adsorption of phenol from aqueous solution using paper waste”, ijcpe, vol. 20, no. 1, pp. 23-29, mar. 2019. [14] a. h. sulaymon, a. a. mohammed, and t. j. al-musawi,2013 “multicomponent biosorption of heavy metals using fluidized bed of algal biomass,” j. eng., vol. 19, no. 4, pp. 469–484. [15] trivizadakis, m.e., karabelas, a. j., 2006, " a study of local liquid/solid mass transfer in packed beds under trickling and induced pulsing flow", chem. eng. sci., 61, 7684-7696. [16] hamm, luther l. 2004. “preliminary ion exchange modeling for removal of cesium from hanford waste using hydrous crystalline silicotitanate material.” savannah river site (us). [17] k. f. al-sultani, 1999“the removal of water pollutants in fluidized bed column by adsorption.” msc. thesis, university of technology, iraq. [18] s. a. m. mohammed, i. faisal, and m. m. alwan, “oily wastewater treatment using expanded beds of activated carbon and zeolite”, ijcpe, vol. 12, no. 1, pp. 1-12, mar. 2011. [19] r. wang, c. kuo, and c. shyu,1997 “adsorption of phenols onto granular activated carbon in a liquid–solid fluidized bed,” j. chem. technol. biotechnol. int. res. process. environ. clean technol., vol. 68, no. 2, pp. 187–194. https://www.sciencedirect.com/science/article/abs/pii/s0143720805000288 https://www.sciencedirect.com/science/article/abs/pii/s0143720805000288 https://www.sciencedirect.com/science/article/abs/pii/s0143720805000288 https://www.sciencedirect.com/science/article/abs/pii/s0143720805000288 https://www.sciencedirect.com/science/article/pii/s0960852499001236 https://www.sciencedirect.com/science/article/pii/s0960852499001236 https://www.sciencedirect.com/science/article/pii/s0960852499001236 https://www.sciencedirect.com/science/article/pii/s0960852499001236 https://www.sciencedirect.com/science/article/pii/s0960852499001236 https://www.sciencedirect.com/science/article/abs/pii/s0143720806000179 https://www.sciencedirect.com/science/article/abs/pii/s0143720806000179 https://www.sciencedirect.com/science/article/abs/pii/s0143720806000179 https://www.sciencedirect.com/science/article/abs/pii/s0143720806000179 https://www.sciencedirect.com/science/article/abs/pii/s0143720806000283 https://www.sciencedirect.com/science/article/abs/pii/s0143720806000283 https://www.sciencedirect.com/science/article/abs/pii/s0143720806000283 https://www.sciencedirect.com/science/article/abs/pii/s0143720806000283 https://www.tandfonline.com/doi/abs/10.1080/10643380091184237 https://www.tandfonline.com/doi/abs/10.1080/10643380091184237 https://www.tandfonline.com/doi/abs/10.1080/10643380091184237 http://web.usm.my/jps/20-1-09/jps%2020(1)%20art%206%20(59-74).pdf http://web.usm.my/jps/20-1-09/jps%2020(1)%20art%206%20(59-74).pdf http://web.usm.my/jps/20-1-09/jps%2020(1)%20art%206%20(59-74).pdf http://web.usm.my/jps/20-1-09/jps%2020(1)%20art%206%20(59-74).pdf http://www.eeer.org/journal/view.php?number=480 http://www.eeer.org/journal/view.php?number=480 http://www.eeer.org/journal/view.php?number=480 http://www.eeer.org/journal/view.php?number=480 https://www.tandfonline.com/doi/abs/10.1080/09593330309385687 https://www.tandfonline.com/doi/abs/10.1080/09593330309385687 https://www.tandfonline.com/doi/abs/10.1080/09593330309385687 https://www.tandfonline.com/doi/abs/10.1080/09593330309385687 https://www.tandfonline.com/doi/abs/10.1080/09593330309385687 https://www.sciencedirect.com/science/article/pii/s0894177707000313 https://www.sciencedirect.com/science/article/pii/s0894177707000313 https://www.sciencedirect.com/science/article/pii/s0894177707000313 https://www.jstor.org/stable/25038243?seq=1 https://www.jstor.org/stable/25038243?seq=1 https://www.jstor.org/stable/25038243?seq=1 https://www.jstor.org/stable/25038243?seq=1 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/350 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/350 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/350 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/350 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/350 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/350 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/389 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/389 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/389 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/389 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/389 https://doi.org/10.31699/ijcpe.2019.1.4 https://doi.org/10.31699/ijcpe.2019.1.4 https://doi.org/10.31699/ijcpe.2019.1.4 https://www.iasj.net/iasj?func=article&aid=70797 https://www.iasj.net/iasj?func=article&aid=70797 https://www.iasj.net/iasj?func=article&aid=70797 https://www.iasj.net/iasj?func=article&aid=70797 https://www.sciencedirect.com/science/article/pii/s0009250906005768 https://www.sciencedirect.com/science/article/pii/s0009250906005768 https://www.sciencedirect.com/science/article/pii/s0009250906005768 https://www.sciencedirect.com/science/article/pii/s0009250906005768 https://inis.iaea.org/search/search.aspx?orig_q=rn:35085918 https://inis.iaea.org/search/search.aspx?orig_q=rn:35085918 https://inis.iaea.org/search/search.aspx?orig_q=rn:35085918 https://inis.iaea.org/search/search.aspx?orig_q=rn:35085918 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/345 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/345 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/345 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/345 https://onlinelibrary.wiley.com/doi/abs/10.1002/(sici)1097-4660(199702)68:2%3c187::aid-jctb651%3e3.0.co;2-1 https://onlinelibrary.wiley.com/doi/abs/10.1002/(sici)1097-4660(199702)68:2%3c187::aid-jctb651%3e3.0.co;2-1 https://onlinelibrary.wiley.com/doi/abs/10.1002/(sici)1097-4660(199702)68:2%3c187::aid-jctb651%3e3.0.co;2-1 https://onlinelibrary.wiley.com/doi/abs/10.1002/(sici)1097-4660(199702)68:2%3c187::aid-jctb651%3e3.0.co;2-1 https://onlinelibrary.wiley.com/doi/abs/10.1002/(sici)1097-4660(199702)68:2%3c187::aid-jctb651%3e3.0.co;2-1 i. s. and a. i. alwared / iraqi journal of chemical and petroleum engineering 20,4 (2019) 55 60 56 امتزاز صبغة الكونغو الحمراء من المحاليل المائية باستخدام قشور الحنطة في مفاعل الحشوة المتميعة 2و عبير الورد 1اسراء صباح وزارة الموارد المائية1 جامعة بغداد-قسم هندسة الهندسة البيئية2 الخالصة يهدف هذا البحث الى دراسة امكانية ازالة الصبغة الكونكو الحمراء من المحاليل المائية باستخدام قشور الحنطة الدالة الحامضية 7.6كمادة ممتزة في مفاعل الحشوة المتميعة حيث اجريت العديد من التجارب بثبات المتغيرات لغرض الحصول عمى مخططات االمتزاز الحيوي لكل ممغم /لتر تركيز اولي لمصبغة وبدرجة حرارة الغرفة 22، ممم / ثانية باستخدام دقائق قطرها 0.6060عنصر و لقد تم الحصول عمى الحد االدنى لسرعة التميع تساوي ( ميكرومتر من قشور الحنطة كما أظهرت النتائج مالئمة بشكل جيد مع البيانات التجريبية. تختمف 220) ( مل / دقيقة 120و 100، 00( سم ، معدل التدفق )10، 2، 2ارتفاع السرير )ظروف التشغيل المختمفة: لمكونغو األحمر ، و تظهر النتائج رسم المخططات( ميكرومتر. تم 1000، 700، 220وقطر الجسيمات ) حمول أن انخفاض حشوة السرير المميع يتوافق مع كمية أقل من الممتزات وسعة ضعيفة لمحشوة المتميعة من الم كما أن زيادة معدل التدفق سيزيد من معدل نقل الكتمة. مفاعل الحشوة المتيعية : صبغة الكونكو الحمراء، قشور الحنطة، الدالةالكممات available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.22 no.2 (june 2021) 1 – 6 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: ammar s. abbas, email: ammarabbas@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. prepared 13x zeolite as a promising adsorbent for the removal of brilliant blue dye from wastewater suondos k. a. barno a , haider j. mohamed b , siham m. saeed b , mohammed j. alani b , and ammar s. abbas c a presidency of the university of baghdad, baghdad, iraq. b chemical and petrochemical center, industrial research and development authority, ministry of industry and minerals, iraq. c chemical engineering department, college of engineering university of baghdad, baghdad, iraq. abstract the research discussed the possibility of adsorption of brilliant blue dye (bbd) from wastewater using 13x zeolite adsorbent, which is considered a byproduct of the production process of potassium carbonate from iraqi potash raw materials. the 13x zeolite adsorbent was prepared and characterized by x-ray diffraction that showed a clear match with the standard 13x zeolite. the crystallinity rate was 82.15% and the crystal zeolite size was 5.29 nm. the surface area and pore volume of the obtained 13x zeolite were estimated. the prepared 13x zeolite showed the ability to remove bbd contaminant from wastewater at concentrations 5 to 50 ppm and the removal reached 96.60% at the lower pollutant concentration. adsorption measurements versus time showed 48.18% removal of the dye during just the first half-hour and the maximum removal closest to the removal at the equilibrium after one and half hour. langmuir isotherm was described the adsorption equilibrium data with a maximum adsorption capacity of 93.46 mg/g and the kinetics data of the adsorption process was followed the pseudo-second-order. keywords: 13x zeolite, adsorbent, brilliant blue dye, adsorption, wastewater. received on 28/03/2021, accepted on 11/05/2021, published on 30/06/2021 https://doi.org/10.31699/ijcpe.2021.2.1 1introduction bbd is a disodium salt (c37h34n2na2o9s3) produced by the condensation reaction of 2formylbenzenesulfonic acid and aniline, followed by oxidation of the condensation product. this synthetic dye is classified as one of the triarylmethane dyes families [1]. the bbd has a color index of 42090 and is known in various commercial names such as acid blue 9, fd&x blue no.1, and the most commonly used name is e133 with cas registry number 3844-45-9 [2]. bbd is a commonly used dye in food industries since 1929. until now, the use of brilliant blue as a food color additive at current levels does not present a safety concern to humans, but reaching this dye to water streams and accumulated it in the tissues of the marine organisms, especially fish and sea fruits and causes severe problems for these organisms, which will quickly affect the human health [2]-[4]. different methods are applied for treating organic pollutants for water depend on treated water amount, pollutants concentration, and purity level. generally, treating organic matter can be classified into physical, chemical, and/or biological methods [5]. however, there are many elimination methods of pollutants in wastewater; the adsorption process is the most common because of its simplicity, ease of use, and low operation cost [6], [7]. still, the adsorption processes' most significant challenge is to find new and environmentally friendly adsorbents or improve the known adsorbents [8]. the well-known adsorbent used to adsorb different organic contaminants and/or dyes from wastewater are charcoal/activated charcoal [9]–[12], activated carbon [13]–[16], zeolites [17]–[19], starchbased environmentally friend adsorbent [20]–[24]. the present work aimed to convert a low cost locally available iraqi potash ore to prepare a 13x zeolite adsorbent (13xza), which is produced as a byproduct during potassium carbonate production via hydrothermal method. the prepared 13xza was characterized by x-ray diffraction (xrd), the surface area, and the pore volume. the prepared 13xza used to adsorb bbd and both equilibrium adsorption and kinetics were studied and discussed. 2experimental work 2.1. preparation and characterization of 13xza the 13xza was prepared hydrothermally from iraqi potash ore (potassium feldspar powder) according to the previous work [25]. potassium feldspar powder used in this study was obtained from the department of geological mining of the ministry of industry in baghdad. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:ammarabbas@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2021.2.1 s. k. a. barno et al. / iraqi journal of chemical and petroleum engineering 22,2 (2021) 1 6 2 the prepared zeolite was characterized by xrd in the chemical and petrochemical center, industrial research and development authority, ministry of industry, and minerals. the crystallinity was determined by dividing the sum of crystalline peaks area of the prepared 13xza on the sum of all peaks area of crystalline and amorphous (eq. 1), and the average crystal size of the prepared 13xza was determined by scherrer's relationship (eq.2). finally, the surface area and pore volume of the adsorbent were measured using brunauer–emmett–teller (bet) method via surface area analyzer/q surf series/italy in the oil development and research center ministry of oil. (crystal) crystallinity, % = 100% (crystal amorphaus) area area     (1)  cos k d     (2) where, d = crystallite size in nm, k = dimensionless crystallite shape factor (typical value is 0.9), λ = wavelength of the x-ray = 1.5406 å, 𝛽 = full width at half maximum (fwhm), rad, and θ = bragg angle, rad. 2.2. adsorption of bbd batch adsorption experiments were carried out by using 0.025 g of 13xza for every 50 ml of the wastewater containing a different initial concentration of bbd (co between 5 to 50 ppm). the solutions were put on a shaker with a uniform speed of 200 rpm at an ambient temperature of 25±3 °c for 24 hours to reach the equilibrium state. the amount of the equilibrium concentration (ce) was reported by averaging the dye concentration values after treatment and then the amount of adsorbed bbd per weight of 13xza (adsorption capacity) at equilibrium (qe, mg/g) was calculated from eq. (3).  e o e v q c c m    (3) where 𝑞𝑒 is the adsorption capacity of the adsorbent (mg/g), 𝐶𝑜 and 𝐶𝑒 in (mg/l) refer to initial and final (equilibrium) concentrations of bbd in the adsorption solution. v (l) is the volume of adsorption solution and m (g) is the weight of 13xza used. the kinetics experiment carried out using a1000 ml of the 50 ppm bbd and one gram of the prepared 13xza have been put together in the beaker and the magnetic stirrer speed kept at 200 rpm. at each interval up to 180 minutes, two samples of 5 ml of the mixture were taken and the average concentration of bbd was measured and reported. while adsorbent performance for the removal of bbd was calculated by eq. (4). bbd removal, %= 100%o t o c c c   (4) the bbd concentration (in batch and kinetics experiments) was measured at 628 nm wavelength using shimadzu uv-160a uv-vis recording spectrophotometer in the chemical engineering department, college of engineering, university of baghdad. 2.3. adsorption isotherms and kinetics models the adsorption isotherms demonstrate the interaction between the adsorbates and adsorbents. most widespread two-parameter isotherms were selected to describe the adsorption of bbd on the prepared 13xza. these isotherms models are langmuir (eq. (5)) [26] and freundlich (eq. (6)) [27]. max 1 l e e l e q k c q k c   (5) 1 n e f e q k c (6) where 𝑞𝑒 adsorption capacity mg adsorbate per g adsorbent, 𝐶𝑒 is the concentration at equilibrium mg/l, 𝑞𝑚𝑎𝑥 is the maximum adsorption capacity in forming a complete monolayer on the surface mg/g, 𝐾𝐿 is langmuir coefficient related to the affinity between the adsorbate and adsorbent (l/mg), 𝐾𝐹 is the freundlich coefficient and n is the number of multilayers. adsorption–kinetics models [28] were used to describe the adsorption capacity variation with time. these models are; pseudo-first order (eq. 7) [29], pseudo-second-order (eq.8) [30], and intraparticle diffusion model (eq. 9).   1e t eln q q lnq k t   (7) 2 1 t e e t t q k q q   (8) 3 1 2 t ctq k  (9) where 𝑞𝑒 and 𝑞𝑡 (in mg/g) are the adsorption capacity at equilibrium and any time (t), respectively. 𝑘1 (1/min), 𝑘2 (g/mg.min), and 𝑘3 (mg/(g.min 0.5 )) are the adsorption rate constants for pseudo-first order, pseudo-second order, and intraparticle diffusion kinetic models, respectively. as well as, c (in eq. (9)) is an arbitrary constant for the intraparticle diffusion. s. k. a. barno et al. / iraqi journal of chemical and petroleum engineering 22,2 (2021) 1 6 3 3results and discussion 3.1. characterization of 13xza xrd is an effective analysis and identification technique used to identify the phase of 13xza crystalline during crystal formation from raw materials and can provide information on unit cell size. the results of the xrd demonstrated in fig. 1 showed a clear correspondence in the places of the peaks with the results of the previous study [25]. the calculated crystallinity value by eq. (1) was 82.15% and the crystal size computed by scherrer's equation (eq. (2)) was 5.29 nm. the current results show a slightly decrease in the crystallinity value due to fewer intensity values of the xrd peaks and the crystal size is very closed to the value of the previous work [25]. this convergence in crystal size of the 13xza indicates that all the width of the peaks of the xrd results is in the same magnitude. however, the measured surface area and pore volume were equal to 395.48 m 2 /g and 0.2405 cm 3 /g, respectively. fig. 1. xrd pattern of the hydrothermal prepared 13xza 3.2. adsorption of bbd on the 13xza a. equilibrium and adsorption isotherms the adsorption process at equilibrium provides important data on the effect of the initial concentration of the dye on the adsorption capacity of the adsorbent and the amount of removal at equilibrium. the equilibrium data will be important in calculations of equilibrium isotherms, which will provide important figures, including maximum adsorption capacity. as shown in fig. 2, the batch adsorption results of bbd on the prepared 13xza showed a sharp increase in the equilibrium adsorption capacity from 9.66 to 80.78 mg/g of adsorbent, while the equilibrium removal values showed a decrease from 96.60 to 80.78% with an increase in the bbd concentration from 5 to 50 ppm. the decrease in the removal values with the increasing the initial concentration is due to competition of dye molecules on the effective adsorption sites on the surface and pores of the 13xza. this competition decreases when using low concentrations, which cause an increase in the dye's adsorption and thus an increase in the amount of removal is observed. fig. 2. effect of initial bbd concentration on the equilibrium capacity (blue line, left y-axis) of the13xza and equilibrium removal (red line, right y-axis) the isotherm constants were determined using the equilibrium data and summarized in table 1. obtained equilibrium data are highly correlated with both isotherms (high correlation coefficients, r 2 ). these isotherms are describing two extremely different phenomena, the langmuir isotherm describing homogeneous monolayer adsorption, while the freundlich isotherm relating heterogeneous multilayer adsorption. therefore, both isotherms were plotted with the obtained experimental equilibrium data in fig. 3. table 1. adsorption isotherm models constants and correlation coefficients (r 2 ) for the removal of bbd on the 13xza isotherm model model constant, unit constant value r 2 langmuir 𝑞𝑚𝑎𝑥, mg/g 93.46 0.9997 𝐾𝐿, l/mg 1.534 freundlich 𝐾𝐹, mg 1-n l n /g 31.13 0.9995 n, 1.98 fig. 3. effect of the equilibrium bbd concentration on the equilibrium adsorption capacities of the 13xza compared with langmuir (blue line) and freundlich (red line) isotherms s. k. a. barno et al. / iraqi journal of chemical and petroleum engineering 22,2 (2021) 1 6 4 as shown from fig. 3, the langmuir isotherm describing the experimentally obtained data better than the freundlich isotherm which is deviated out the data at the values of equilibrium concentration (ce) more than about 7. so, the langmuir isotherm explains the obtained experimental equilibrium date of bbd adsorption on the prepared 13xza with a maximum adsorption capacity of 93.46 mg/g (mg of bbd per g of the adsorbent), with langmuir coefficient 𝐾𝐿 equal to 1.534 l/mg. b. effect of time and the adsorption kinetics the concentration of bbd decreasing with the time that correlated with an increase in the amount of bbd removal from the wastewater as shown in fig. 4. at the first 30 minutes, the concentration of bbd was dropped sharply with about 48.18% of its initial value. after that, the removal of bbd became slower until about 90 minutes with 77.40 % removal, and then the growth in the removal was very slightly with increasing adsorption time (80.76% removal after 180 minutes (3 hours), and 80.78% removal after 24 hours (at assumed equilibrium conditions). the relatively fast adsorption at the beginning was because of the high concentration difference (the mass transfer driving force) between the solution and the “clean” surface of the 13xza. over time, more bbd adsorbed on the surface that occupied more pores and adsorption sites, which decreasing in the mass transfer driving force, and causing a slowing in the adsorption rate and stopped it at equilibrium. the kinetic results of the adsorption of the bbd from wastewater on the prepared 13xza according to the correlation of concentration versus time data with adsorption kinetics models (eq. (7-9)) are summarized in table 2. the obtained values of the r 2 indicate a well fit of the obtained data with the pseudo-second-order model (eq. 8) with a rate constant equal to 0.0333 g/mg.min. fig. 4. bbd concentration (blue line, left y-axis) and removal (red line, right y-axis) versus the time of the adsorption over the 13xza table 2. adsorption kinetics models constants and correlation coefficients (r 2 ) for the adsorption of bbd on the 13xza adsorption kinetic model model constant, unit constant value pseudo-first order 𝑘1, l/min 0.0533 𝑞𝑒, mg/g 84.98 r² 0.8661 pseudo-second order 𝑘2, g/mg.min 0.0333 𝑞𝑒, mg/g 48.78 r² 0.9941 intraparticle diffusion k3, mg/g.min 0.5 3.1971 c, mg/g 4.7826 r 2 0.8868 4conclusion iraqi potash ore was a good source of preparing 13xza by the hydrothermal method as a byproduct in the production of potassium carbonate. the prepared 13xza have 82.15% crystallinity, crystal size of 5.29 nm, surface area of 395.48 m 2 /g and 0.2405 cm 3 /g pore volume. prepared 13xza show ability to remove bbd from wastewater in the concentrations ranged between 5 to 50 ppm. the removal was decreasing from 96.60 to 80.78% by increasing the initial concentrations. the adsorption equilibrium data analysis show that langmuir isotherm describes better the adsorption of bbd on 13xza with maximum adsorption capacity of 93.46 mg/g. adsorption measurements versus time recorded 48.18% removal during first 30 minutes, and the removal reached closely to the equilibrium value after 90 minutes. while the adsorption kinetics analysis shows that the adsorption of bbd on 13xza followed the pseudo-second order with a rate constant equal to 0.0333 g/mg.min. references [1] m. f. ali, b. m. el ali, and j. g. speight, handbook of industrial chemistry: organic chemicals. new york, united states of america: mcgraw-hill education; 1st edition, 2005. [2] european food safety authority (efsa), “scientific opinion on the re-evaluation of brilliant blue fcf (e 133) as a food additive,” efsa j., vol. 8, no. 11, pp. 1–36, 2010, doi: 10.2903/j.efsa.2010.1853. [3] r.w. sabnis, handbook of biological dyes and stains synthesis and industrial applications. hoboken, new jersey: a john wiley & sons, inc., 2010. [4] l. g. b. ferreira, r. x. faria, n. c. d. s. ferreira, and r. j. soares-bezerra, “brilliant blue dyes in daily food: how could purinergic system be affected?,” international journal of food science, vol. 2016. hindawi limited, 2016, doi: 10.1155/2016/7548498. [5] a. p. trzcinski, advanced biological, physical, and chemical treatment of waste activated sludge, 1st editio. crc press, taylor & francis group, 2019. [6] p. le cloirec, “adsorption in water and wastewater treatments,” in handbook of porous solids, vol. 58, no. 1, weinheim, germany: wiley-vch verlag gmbh, 1976, pp. 2746–2803. https://www.accessengineeringlibrary.com/content/book/9780071410373 https://www.accessengineeringlibrary.com/content/book/9780071410373 https://www.accessengineeringlibrary.com/content/book/9780071410373 https://www.accessengineeringlibrary.com/content/book/9780071410373 https://efsa.onlinelibrary.wiley.com/doi/abs/10.2903/j.efsa.2010.1853 https://efsa.onlinelibrary.wiley.com/doi/abs/10.2903/j.efsa.2010.1853 https://efsa.onlinelibrary.wiley.com/doi/abs/10.2903/j.efsa.2010.1853 https://efsa.onlinelibrary.wiley.com/doi/abs/10.2903/j.efsa.2010.1853 https://books.google.iq/books?hl=en&lr=&id=_la8dwaaqbaj&oi=fnd&pg=pr17&dq=%5b3%5d%09r.w.+sabnis,+handbook+of+biological+dyes+and+stains+synthesis+and+industrial+applications.+hoboken,+new+jersey:+a+john+wiley+%26+sons,+inc.,+2010.&ots=kunp4knyuc&sig=_mmsebi_e3f2o8zwqwnj-1clbfu&redir_esc=y#v=onepage&q=%5b3%5d%09r.w.%20sabnis%2c%20handbook%20of%20biological%20dyes%20and%20stains%20synthesis%20and%20industrial%20applications.%20hoboken%2c%20new%20jersey%3a%20a%20john%20wiley%20%26%20sons%2c%20inc.%2c%202010.&f=false https://books.google.iq/books?hl=en&lr=&id=_la8dwaaqbaj&oi=fnd&pg=pr17&dq=%5b3%5d%09r.w.+sabnis,+handbook+of+biological+dyes+and+stains+synthesis+and+industrial+applications.+hoboken,+new+jersey:+a+john+wiley+%26+sons,+inc.,+2010.&ots=kunp4knyuc&sig=_mmsebi_e3f2o8zwqwnj-1clbfu&redir_esc=y#v=onepage&q=%5b3%5d%09r.w.%20sabnis%2c%20handbook%20of%20biological%20dyes%20and%20stains%20synthesis%20and%20industrial%20applications.%20hoboken%2c%20new%20jersey%3a%20a%20john%20wiley%20%26%20sons%2c%20inc.%2c%202010.&f=false https://books.google.iq/books?hl=en&lr=&id=_la8dwaaqbaj&oi=fnd&pg=pr17&dq=%5b3%5d%09r.w.+sabnis,+handbook+of+biological+dyes+and+stains+synthesis+and+industrial+applications.+hoboken,+new+jersey:+a+john+wiley+%26+sons,+inc.,+2010.&ots=kunp4knyuc&sig=_mmsebi_e3f2o8zwqwnj-1clbfu&redir_esc=y#v=onepage&q=%5b3%5d%09r.w.%20sabnis%2c%20handbook%20of%20biological%20dyes%20and%20stains%20synthesis%20and%20industrial%20applications.%20hoboken%2c%20new%20jersey%3a%20a%20john%20wiley%20%26%20sons%2c%20inc.%2c%202010.&f=false https://www.hindawi.com/journals/ijfs/2016/7548498/ https://www.hindawi.com/journals/ijfs/2016/7548498/ https://www.hindawi.com/journals/ijfs/2016/7548498/ https://www.hindawi.com/journals/ijfs/2016/7548498/ https://www.hindawi.com/journals/ijfs/2016/7548498/ https://books.google.iq/books?hl=en&lr=&id=-zx3dwaaqbaj&oi=fnd&pg=pp1&dq=advanced+biological,+physical,+and+chemical+treatment+of+waste+activated+sludge&ots=b4puwfefen&sig=wimh3lchdqmbsm_vbq_oxo7zptu&redir_esc=y#v=onepage&q=advanced%20biological%2c%20physical%2c%20and%20chemical%20treatment%20of%20waste%20activated%20sludge&f=false https://books.google.iq/books?hl=en&lr=&id=-zx3dwaaqbaj&oi=fnd&pg=pp1&dq=advanced+biological,+physical,+and+chemical+treatment+of+waste+activated+sludge&ots=b4puwfefen&sig=wimh3lchdqmbsm_vbq_oxo7zptu&redir_esc=y#v=onepage&q=advanced%20biological%2c%20physical%2c%20and%20chemical%20treatment%20of%20waste%20activated%20sludge&f=false https://books.google.iq/books?hl=en&lr=&id=-zx3dwaaqbaj&oi=fnd&pg=pp1&dq=advanced+biological,+physical,+and+chemical+treatment+of+waste+activated+sludge&ots=b4puwfefen&sig=wimh3lchdqmbsm_vbq_oxo7zptu&redir_esc=y#v=onepage&q=advanced%20biological%2c%20physical%2c%20and%20chemical%20treatment%20of%20waste%20activated%20sludge&f=false https://onlinelibrary.wiley.com/doi/abs/10.1002/9783527618286.ch36 https://onlinelibrary.wiley.com/doi/abs/10.1002/9783527618286.ch36 https://onlinelibrary.wiley.com/doi/abs/10.1002/9783527618286.ch36 https://onlinelibrary.wiley.com/doi/abs/10.1002/9783527618286.ch36 s. k. a. barno et al. / iraqi journal of chemical and petroleum engineering 22,2 (2021) 1 6 5 [7] a. bonilla-petriciolet, d. i. mendoza-castillo, and h. e. reynel-ávila, eds., adsorption processes for water treatment and purification. springer international publishing, 2017. [8] a. bhatnagar, ed., application of adsorbents for water pollution control. bentham science publishers, 2012. [9] d. suteu and d. bilba, “suteu and bilba brilliant red he-3b adsorption equilibrium and kinetic study of reactive dye brilliant red he-3b adsorption by activated charcoal,” acta chim. slov, vol. 52, pp. 73– 79, 2005. [10] h. a. shanshool, “adsorption of methylene blue on prepared charcoal from molasses waste,” j. eng., vol. 25, no. 9, pp. 92–104, 2019, doi: 10.31026/j.eng.2019.9.8. [11] s. k. a. barno and a. s. abbas, “reduction of organics in dairy wastewater by adsorption on a prepared charcoal from iraqi sugarcane,” iop conf. ser. mater. sci. eng., vol. 736, no. 2, 2020, doi: 10.1088/1757-899x/736/2/022096. [12] s. m. yakout, m. r. hassan, a. a. abdeltawab, and m. i. aly, “sono-sorption efficiencies and equilibrium removal of triphenylmethane (crystal violet) dye from aqueous solution by activated charcoal,” j. clean. prod., vol. 234, pp. 124–131, oct. 2019, doi: 10.1016/j.jclepro.2019.06.164. [13] a. s. abbas and t. darweesh, “preparation and characterization of activated carbon for adsorption of,” j. eng., vol. 22, no. 8, pp. 140–157, 2016. [14] s. h. tang and m. a. ahmad zaini, “development of activated carbon pellets using a facile low-cost binder for effective malachite green dye removal,” j. clean. prod., vol. 253, p. 119970, apr. 2020, doi: 10.1016/j.jclepro.2020.119970. [15] m. a. ahmad, m. a. eusoff, p. o. oladoye, k. a. adegoke, and o. s. bello, “statistical optimization of remazol brilliant blue r dye adsorption onto activated carbon prepared from pomegranate fruit peel,” chem. data collect., vol. 28, p. 100426, aug. 2020, doi: 10.1016/j.cdc.2020.100426. [16] a. h. jawad, n. n. mohd firdaus hum, a. s. abdulhameed, and m. a. mohd ishak, “mesoporous activated carbon from grass waste via h3po4activation for methylene blue dye removal: modelling, optimisation, and mechanism study,” int. j. environ. anal. chem., 2020, doi: 10.1080/03067319.2020.1807529. [17] a. s. abbas and s. a. hussien, “equilibrium , kinetic and thermodynamic study of aniline adsorption over prepared zsm-5 zeolite,” iraqi j. chem. pet. eng., vol. 18, no. 1, pp. 47–56, 2017. [18] m. tanyol, n. kavak, and g. torlut, “synthesis of poly(an-co-vp)/zeolite composite and its application for the removal of brilliant green by adsorption process: kinetics, isotherms, and experimental design,” adv. polym. technol., vol. 2019, 2019, doi: 10.1155/2019/8482975. [19] h. mittal, r. babu, a. a. dabbawala, s. stephen, and s. m. alhassan, “zeolite-y incorporated karaya gum hydrogel composites for highly effective removal of cationic dyes,” colloids surfaces a physicochem. eng. asp., vol. 586, p. 124161, feb. 2020, doi: 10.1016/j.colsurfa.2019.124161. [20] y. li, y. liu, h. tang, and s. dong, “oxidized cross-linked guar gum with hydrophobic groups: structure, properties and removal of reactive bluexbr in simulated water,” arab. j. sci. eng., vol. 43, no. 7, pp. 3621–3629, jul. 2018, doi: 10.1007/s13369018-3146-x. [21] r. k. abid and a. s. abbas, “adsorption of organic pollutants from real refinery wastewater on prepared cross-linked starch by epichlorohydrin,” data br., vol. 19, pp. 1318–1326, 2018, doi: 10.1016/j.dib.2018.05.060. [22] f. k. al-jubory, i. m. mujtaba, and a. s. abbas, “preparation and characterization of biodegradable crosslinked starch ester as adsorbent,” in 2nd international conference on materials engineering & science (iconmeas 2019), 2020, pp. 20165–20169, doi:https://doi.org/10.1063/5.0000170. [23] j. arayaphan, p. maijan, p. boonsuk, and s. chantarak, “synthesis of photodegradable cassava starch-based double network hydrogel with high mechanical stability for effective removal of methylene blue,” int. j. biol. macromol., nov. 2020, doi: 10.1016/j.ijbiomac.2020.11.166. [24] s. lawchoochaisakul, p. monvisade, and p. siriphannon, “cationic starch intercalated montmorillonite nanocomposites as natural based adsorbent for dye removal,” carbohydr. polym., vol. 253, p. 117230, feb. 2021, doi: 10.1016/j.carbpol.2020.117230. [25] b. a. alshahidy and a. s. abbas, “preparation and modification of 13x zeolite as a heterogeneous catalyst for esterification of oleic acid,” in aip conference proceedings, mar. 2020, vol. 2213, no. 1, p. 020167, doi: 10.1063/5.0000171. [26] f. w. clarke and b. irving langmuir, “constitution of solids and liquids,” j. am. chem. soc., vol. 38, no. 11, pp. 2221–2295, 1916, doi: 10.1021/ja02268a002. [27] h.m.f. freundlich, “over the adsorption in solution,” j. phys. chem., vol. 57, pp. 385–471, 1906. [28] k. l. tan and b. h. hameed, “insight into the adsorption kinetics models for the removal of contaminants from aqueous solutions,” j. taiwan inst. chem. eng., vol. 74, pp. 25–48, 2017, doi: 10.1016/j.jtice.2017.01.024. [29] s. lagergren, “zur theorie der sogenannten adsorption geloster stoffe,” k. sven. vetenskapsakademiens. handl., vol. 24, pp. 1–39, 1898. [30] y. . ho and g. mckay, “pseudo-second order model for sorption processes,” process biochem., vol. 34, no. 5, pp. 451–465, jul. 1999, doi: 10.1016/s00329592(98)00112-5. https://link.springer.com/book/10.1007%2f978-3-319-58136-1 https://link.springer.com/book/10.1007%2f978-3-319-58136-1 https://link.springer.com/book/10.1007%2f978-3-319-58136-1 https://link.springer.com/book/10.1007%2f978-3-319-58136-1 https://books.google.iq/books?hl=en&lr=&id=trcpdgaaqbaj&oi=fnd&pg=pp2&dq=application+of+adsorbents+for+water+pollution+control&ots=zq5yuonvfv&sig=vjywadzl8zpexslwmvbu2mg3wbe&redir_esc=y#v=onepage&q=application%20of%20adsorbents%20for%20water%20pollution%20control&f=false https://books.google.iq/books?hl=en&lr=&id=trcpdgaaqbaj&oi=fnd&pg=pp2&dq=application+of+adsorbents+for+water+pollution+control&ots=zq5yuonvfv&sig=vjywadzl8zpexslwmvbu2mg3wbe&redir_esc=y#v=onepage&q=application%20of%20adsorbents%20for%20water%20pollution%20control&f=false https://books.google.iq/books?hl=en&lr=&id=trcpdgaaqbaj&oi=fnd&pg=pp2&dq=application+of+adsorbents+for+water+pollution+control&ots=zq5yuonvfv&sig=vjywadzl8zpexslwmvbu2mg3wbe&redir_esc=y#v=onepage&q=application%20of%20adsorbents%20for%20water%20pollution%20control&f=false http://acta-arhiv.chem-soc.si/52/52-1-73.pdf http://acta-arhiv.chem-soc.si/52/52-1-73.pdf http://acta-arhiv.chem-soc.si/52/52-1-73.pdf http://acta-arhiv.chem-soc.si/52/52-1-73.pdf http://acta-arhiv.chem-soc.si/52/52-1-73.pdf https://doi.org/10.31026/j.eng.2019.9.8 https://doi.org/10.31026/j.eng.2019.9.8 https://doi.org/10.31026/j.eng.2019.9.8 https://doi.org/10.31026/j.eng.2019.9.8 https://iopscience.iop.org/article/10.1088/1757-899x/736/2/022096/meta https://iopscience.iop.org/article/10.1088/1757-899x/736/2/022096/meta https://iopscience.iop.org/article/10.1088/1757-899x/736/2/022096/meta https://iopscience.iop.org/article/10.1088/1757-899x/736/2/022096/meta https://iopscience.iop.org/article/10.1088/1757-899x/736/2/022096/meta https://www.sciencedirect.com/science/article/abs/pii/s0959652619321286 https://www.sciencedirect.com/science/article/abs/pii/s0959652619321286 https://www.sciencedirect.com/science/article/abs/pii/s0959652619321286 https://www.sciencedirect.com/science/article/abs/pii/s0959652619321286 https://www.sciencedirect.com/science/article/abs/pii/s0959652619321286 https://www.sciencedirect.com/science/article/abs/pii/s0959652619321286 https://joe.uobaghdad.edu.iq/index.php/main/article/view/160 https://joe.uobaghdad.edu.iq/index.php/main/article/view/160 https://joe.uobaghdad.edu.iq/index.php/main/article/view/160 https://www.sciencedirect.com/science/article/abs/pii/s0959652620300172 https://www.sciencedirect.com/science/article/abs/pii/s0959652620300172 https://www.sciencedirect.com/science/article/abs/pii/s0959652620300172 https://www.sciencedirect.com/science/article/abs/pii/s0959652620300172 https://www.sciencedirect.com/science/article/abs/pii/s0959652620300172 https://www.sciencedirect.com/science/article/abs/pii/s240583002030135x https://www.sciencedirect.com/science/article/abs/pii/s240583002030135x https://www.sciencedirect.com/science/article/abs/pii/s240583002030135x https://www.sciencedirect.com/science/article/abs/pii/s240583002030135x https://www.sciencedirect.com/science/article/abs/pii/s240583002030135x https://www.sciencedirect.com/science/article/abs/pii/s240583002030135x https://www.tandfonline.com/doi/abs/10.1080/03067319.2020.1807529 https://www.tandfonline.com/doi/abs/10.1080/03067319.2020.1807529 https://www.tandfonline.com/doi/abs/10.1080/03067319.2020.1807529 https://www.tandfonline.com/doi/abs/10.1080/03067319.2020.1807529 https://www.tandfonline.com/doi/abs/10.1080/03067319.2020.1807529 https://www.tandfonline.com/doi/abs/10.1080/03067319.2020.1807529 https://www.tandfonline.com/doi/abs/10.1080/03067319.2020.1807529 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/192 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/192 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/192 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/192 https://www.hindawi.com/journals/apt/2019/8482975/ https://www.hindawi.com/journals/apt/2019/8482975/ https://www.hindawi.com/journals/apt/2019/8482975/ https://www.hindawi.com/journals/apt/2019/8482975/ https://www.hindawi.com/journals/apt/2019/8482975/ https://www.hindawi.com/journals/apt/2019/8482975/ https://www.sciencedirect.com/science/article/abs/pii/s0927775719311549 https://www.sciencedirect.com/science/article/abs/pii/s0927775719311549 https://www.sciencedirect.com/science/article/abs/pii/s0927775719311549 https://www.sciencedirect.com/science/article/abs/pii/s0927775719311549 https://www.sciencedirect.com/science/article/abs/pii/s0927775719311549 https://www.sciencedirect.com/science/article/abs/pii/s0927775719311549 https://link.springer.com/article/10.1007/s13369-018-3146-x https://link.springer.com/article/10.1007/s13369-018-3146-x https://link.springer.com/article/10.1007/s13369-018-3146-x https://link.springer.com/article/10.1007/s13369-018-3146-x https://link.springer.com/article/10.1007/s13369-018-3146-x https://link.springer.com/article/10.1007/s13369-018-3146-x https://www.sciencedirect.com/science/article/pii/s2352340918305663 https://www.sciencedirect.com/science/article/pii/s2352340918305663 https://www.sciencedirect.com/science/article/pii/s2352340918305663 https://www.sciencedirect.com/science/article/pii/s2352340918305663 https://www.sciencedirect.com/science/article/pii/s2352340918305663 https://aip.scitation.org/doi/abs/10.1063/5.0000170 https://aip.scitation.org/doi/abs/10.1063/5.0000170 https://aip.scitation.org/doi/abs/10.1063/5.0000170 https://aip.scitation.org/doi/abs/10.1063/5.0000170 https://aip.scitation.org/doi/abs/10.1063/5.0000170 https://aip.scitation.org/doi/abs/10.1063/5.0000170 https://www.sciencedirect.com/science/article/abs/pii/s0141813020350911 https://www.sciencedirect.com/science/article/abs/pii/s0141813020350911 https://www.sciencedirect.com/science/article/abs/pii/s0141813020350911 https://www.sciencedirect.com/science/article/abs/pii/s0141813020350911 https://www.sciencedirect.com/science/article/abs/pii/s0141813020350911 https://www.sciencedirect.com/science/article/abs/pii/s0141813020350911 https://www.sciencedirect.com/science/article/abs/pii/s014486172031403x https://www.sciencedirect.com/science/article/abs/pii/s014486172031403x https://www.sciencedirect.com/science/article/abs/pii/s014486172031403x https://www.sciencedirect.com/science/article/abs/pii/s014486172031403x https://www.sciencedirect.com/science/article/abs/pii/s014486172031403x https://www.sciencedirect.com/science/article/abs/pii/s014486172031403x https://aip.scitation.org/doi/abs/10.1063/5.0000171 https://aip.scitation.org/doi/abs/10.1063/5.0000171 https://aip.scitation.org/doi/abs/10.1063/5.0000171 https://aip.scitation.org/doi/abs/10.1063/5.0000171 https://aip.scitation.org/doi/abs/10.1063/5.0000171 https://www.sciencedirect.com/science/article/abs/pii/s1876107017300378 https://www.sciencedirect.com/science/article/abs/pii/s1876107017300378 https://www.sciencedirect.com/science/article/abs/pii/s1876107017300378 https://www.sciencedirect.com/science/article/abs/pii/s1876107017300378 https://www.sciencedirect.com/science/article/abs/pii/s1876107017300378 https://www.sid.ir/en/journal/viewpaper.aspx?id=263167 https://www.sid.ir/en/journal/viewpaper.aspx?id=263167 https://www.sid.ir/en/journal/viewpaper.aspx?id=263167 https://www.sid.ir/en/journal/viewpaper.aspx?id=263167 https://journals.sagepub.com/doi/abs/10.1243/1350650991542802 https://journals.sagepub.com/doi/abs/10.1243/1350650991542802 https://journals.sagepub.com/doi/abs/10.1243/1350650991542802 https://journals.sagepub.com/doi/abs/10.1243/1350650991542802 s. k. a. barno et al. / iraqi journal of chemical and petroleum engineering 22,2 (2021) 1 6 6 مةة م ميا الصر الكممتز واعد الزالة الصبغة الزرقاء ال 13x تحضير زيواليت عمار عباس 3محمد الةاني و 2سهام سةيد, 2حيدر محمد, 2رنو, سندس ب 1 رئاسة جامعة بغداد, بغداد, العراق 1 وزارة الصناعة والمعادن, بغداد, العراق 2 جامعة بغداد/كلية الهندسة/قسم الهندسة الكيمياوية, بغداد, العراق 3 الخالصة من مياه الصرف الصحي باستخدام الزيواليت من نوع الزرقاء الالمعةناقش البحث امكانية امتزاز الصبغة 13x كمادة ممتزة والتي تعتبر منتج ثانوي لعملية انتاج كربونات البوتاسيوم من مواد البوتاس العراقية االولية. تم مع زيوليت تحضير مادة االمتزاز و تشخيصه بأستخدام انحراف األشعة السينية و الذي أظهر تطابًقا واضًحا 13x نانومتر، كما و تم تقدير 5.29٪ و كان حجم الزيوليت البلوري 82.15القياسي. و قد بلغ معدل التبلور من المحضر القدرة على إزالة الصبغة 13xمساحة السطح و حجم المسام للزيوليت المحضر. أظهر زيوليت ٪ عند أقل تركيز 96.60إزالة كانت بمقدار جزء في المليون و وجدت أعلى 50إلى 5مياه الصرف بتركيزات ٪ من الصبغة خالل النصف ساعة األولى فقط 48.18للملوث. أظهرت قياسات االمتزاز مقابل الوقت إزالة وحصلنا على أقصى إزالة بعد ساعة ونصف. وصف متساوي الحرارة النجموير بيانات توازن االمتزاز بشكل مجم / جم وقد كانت البيانات الحركية لعملية االمتزاز تتبع 93.46أفضل و كانت سعة االمتزاز القصوى حركية الدرجة الثانية الزائفة. ، مادة ممتزة، الزرقاء الالمعة، امتزاز، مياه صرف.13xة: زيوليت الدالالكلمات iraqi journal of chemical and petroleum engineering vol.18 no.1 (march 2017) 87 98 issn: 1997-4884 removal of ni(ii), pb(ii), and cu(ii) from industrial wastewater by using nf membrane ahmed h. algureiri and yossor r. abdulmajeed chemical engineering department – college of engineering – university of nahrain e-mail: gureiri71@gmail.com and yossor_riadh@yahoo.com abstract this article reviews the technical applicability of nanofiltration membrane process for the removal of nickel, lead, and copper ions from industrial wastewater. synthetic industrial wastewater samples containing ni(ii), pb(ii), and cu(ii) ions at various concentrations (50, 100, 150 and 200 ppm), under different pressures (1, 2, 3 and 4 bar), temperatures (10, 20, 30 and 40 o c), ph (2, 3, 4, 5 and 5.5), and flow rates (1, 2, 3 and 4 l/hr), were prepared and subjected treated by nf systems in the laboratory. suitable nf membrane was chosen after testing a number of nf membranes (university of technology-baghdad), in terms of production and removal. nf system was capable of removing more than (85%, 78%, and 66% for ni(ii), pb(ii), and cu(ii) ions respectively). the permeate flux for all h.m ions for were ranges between (14 to 62 l/m 2 .hr). the results showed that the nf membrane was capable of treating industrial wastewater with any concentration of heavy metals ions and reducing the ion concentration to about (15, 22, and 34 ppm) for ni(ii), pb(ii), and cu(ii) ions respectively. the low level of the heavy metals concentration in the permeate implies that water with good quality could be reclaimed for further reuse. the nf membrane is characterized by efficiently h.m. ions removal medium with high productivity and very low pressure up to 1 bar, which means very little cost for nf system. introduction the use of effective technologies, such as membranes, for wastewater treatment containing heavy metals ions will allow the implementation of water recycling systems in industrial facilities [1], as well as reduce harmful effect of metal content in the returned water to the natural water sources or to land. as a result, wastewater discharge cost and freshwater supply payments will decrease, and reduce environmental risks. the world health organization (who) has identified heavy metals allowed for drinking water, as well as the appropriate levels for agriculture and soil and marine and other district level [2]. table 1 shows the minerals that can be contained in industrial water, and the highest allowable limit for drinking water, according to the world health organization. use of most techniques (except nanofiltration and reverse osmosis), can be practical and cost-effective only with concentrated wastewater (contain university of baghdad college of engineering iraqi journal of chemical and petroleum engineering mailto:gureiri71@gmail.com mailto:yossor_riadh@yahoo.com removal of ni(ii), pb(ii), and cu(ii) from industrial wastewater by using nf membrane 88 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net high concentration of heavy metal ions), but they will be ineffective when applied to low concentration wastewater that contain heavy ions less than 100 ppm. there are techniques to them effective in the removal of low concentrations of metals ions only, and be inefficient with high concentrations. as for nanofiltration system, it is effective in all concentrations even the very small ones. many natural and synthetic adsorbents can effectively remove dissolved heavy metals; most of them show some disadvantages such as poor adsorption capacity, low efficiency, cost ratio, and ineffectiveness at high metal concentration [3]. nanofiltration membrane processes has been selected because of many advantages of them, as high efficient, low cost, simple operation, and working with any feed concentration. nanofiltration (nf) is a cross flow, pressure driven process that is characterized by a membrane pore size corresponding to molecular weight cutoff of approximately 200 –1000 dalton. three metals were selected for a search (nickel, lead, and copper) ions, as they represent different industries and scattered, with different parameters; concentration, pressure, temperature, ph, and flow rate, the values of parameters was chosen the most appropriate for operating conditions that achieve less cost and best make production. table 1: limits, uses, and toxicity of heavy metals [4] h.m *level of h.m./ppm uses toxicity pb 0.01 building construction, lead acid – battery bullets. negatively influence plant growth. cu 0.1 used as a conductor of heat and electricity, building material, tharanitharan venkatesan, 2014 various alloys. this toxicity possibly due to redox cycling and the generation of reactive oxygen species that damage dna. fe 0.3 found in most industries that use equipment and iron pipes plating shops, wire drawing operations steel mills, and chemical milling. osteoporosis, liver cirrhosis cardiomyopathy arrhythmia heart failure heart attack،hypothyroidism, hypopituitarism ،adrenal gland, neurodegeneration. ni 0.02 used to manufacture stainless steel, nonferrous alloys, batteries, electronics, and aerospace applications. with immoderate amounts, can become toxic. cause liver damage, decreased body weight, heart, and skin agitation. zn 3 used for galvanizing iron, more than 50% of metallic zinc goes into galvanizing steel, also in the preparation of certain alloys, building construction, roofing and gutters, the negative plates in some electric batteries. zinc increase in the blood leads to a sense of bitterness or bitterness mouth food generally, vomiting, nausea and stomach pain, and these symptoms are similar to symptoms of poisoning. hg 0.002 used in equipment (e.g. switches, gauges, thermometers, manometer) and in chemicals (e.g. phenyl mercuric acetate, caustic soda. effects on the nervous, digestive and immune systems, and on lungs, kidneys, skin and eyes. as 0.01 used in paints, dyes, soaps, metals, and semiconductors, mining, agriculture, also as wood preservative. cause skin damage or problems with circulatory system, and an increased risk of getting cancer. http://www.iasj.net/ ahmed h. algureiri and yossor r. abdulmajeed -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 89 removal processes of heavy metals there are many processes for removing heavy metals ions from wastewater like chemical precipitation, coagulation-flocculation, flotation, adsorption, ion-exchange, electrodialysis and membranes system [5]. these processes aim to reduce the amount and proportion of metals to the allowable limit which is not a danger to health or the environment [6]. nanofiltration process nanofiltration (nf) is a pressure driven membrane process. hydraulic pressure is used to overcome the feed solution’s osmotic pressure and to induce diffusion of pure water (referred to as permeate) through a semi-permeable nf membrane. the residual feed stream (referred to concentrate, or reject) is concentrated by the process, and depending on water quality, may be suitable for further water recovery in additional downstream unit processes; otherwise, the residual stream requires disposal. nf is designed to achieve removal of divalent and multivalent ions (e.g., calcium, magnesium, sulfate, iron, arsenic, etc.), and is occasionally referred to as membrane softening. nf may achieve moderate to low removal of monovalent ions (e.g., sodium, potassium, chloride). nf is commonly employed to remove hardness from brackish groundwater to produce potable water. water characterized by high concentrations of calcium or magnesium and monovalent salts may be treated with nf prior to a reverse osmosis, therefore nf is used in drinking water purification system, also in many industrial processes to remove heavy metals and coloring agents. nf seems to be very interesting in view of the high permeate capacity with a low or medium system pressure. another factor is the matter passage; i. e. the content of solid matter in the concentrate is much lower than in the reverse osmosis. this also reduces the costs for disposal of the residues either on site or externally [7]. advantages heavy metals removal by using of nanofiltration includes:  low operating costs  low energy costs  hard water softening  reduction of heavy metals  no chemicals addition  the value of ph after nanofiltration innocuous.  no phase change  simple equipment  effective in all concentrations even small ones. 1. nf membranes models there are many models of nf membrane like spiral wound, disc and tubular. these models are shown in figures 1, 2 and 3, respectively. fig. 1: nf membrane, spiral wound module [8] fig. 2: nf membrane, disc module [8] http://www.iasj.net/ removal of ni(ii), pb(ii), and cu(ii) from industrial wastewater by using nf membrane 90 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net fig. 3: nf membrane, tubular module [8] the most difference between spiral wound, disc and tubular modules is the component density which is clearly highest in the spiral wound modules, that leads to less investment and operation cost [9]. 2. transport mechanism for nf membranes nf process is relatively simple in design. it consists of a feed water source; feed pretreatment, high pressure pump, nf membrane. a schematic of the nf process is shown in figure 4. this figure show three streams of the nf membrane process, the feed; the product stream called permeate, and the concentrated feed stream, called the concentrated or retentive. the water flow through the membrane is reported in terms of water flux. fig. 4: a schematic representation of the nf process there are four types of transport mechanism of membranes: 1bulk flow through membrane pores. 2diffusion through membrane pores. 3restricted diffusion through membranes pores. 4solution-diffusion through dense membranes. the transport mechanism type depends on membrane type. the three first types suitable for mf, and uf membranes (microporous membranes), while the (solution-diffusion), used for ro membrane because it is dense membrane. the behavior of nf membrane is between microporous and dense membrane. experimental work ni(ii), cu(ii) and pb(ii) had been selected in this work. for every test a feed must be prepared firstly by dissolving the required quantity of heavy metal in pure water with required parameters (concentration, pressure, temperature, ph, and feed flow rate), and introduce it to the feed tank. the feed water is pumped from the feed tank and pumping it with different pressures. the change in pressure is done through the gradual closing of the valve of reject water (it should not be closed completely), with reading the feed water pressure gauge (before entering to membrane cell) to http://www.iasj.net/ ahmed h. algureiri and yossor r. abdulmajeed -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 91 get the pressure required for each operation. for obtaining the required feed flow rate control valve is used after the pump and before membrane. the physical and chemical properties of ni(ii), cu(ii) and pb(ii) are listed in table 1. table 1: physical and chemical properties of h.m. [10] h.m. ion chemical formula m.wt (g/mol) density g/cm 3 solubility in water (molal) purity % ni(ii) niso4.6h2o 262.58 1.948 77.5 at 30 o c 99.8 pb(ii) pb(no3)2 331.21 4.53 52 at 20 o c 99.5 cu(ii) cu.so4.5h2o 249.7 2.286 1.502at 30 o c 99.8 the chemicals used to adjust the ph and to clean membranes are presented in table 2: table 2: physical and chemical properties of auxiliary chemicals [11] material m.wt (g/mol) density g/cm 3 nacl 58.44 2.17 hcl 36.46 1.18 naoh 39.997 2.13 three types of nanofiltration membrane have been examined (nf1, nf2 and nf3) to choose the suitable membrane. pure water had been used first, then solution of heavy metals ions. the removal percentage and permeate flux are calculated. the pressure effects on the membrane are also tested. table 3 shows the specification of each type of nf membrane. the nanofiltration membrane (nf1) had been selected because of the high efficiency of the production and removal and withstands the high pressure and heat. figures 5 and 6, show the photographic view of the nf1 membrane and its thickness. table 3: specification of nanofiltration membranes* sample average pore diameter dope composition (wt %) bore fluid composition nmp/water coagulation bath temperature (◦c) extrusion pressure (bar) bore fluid flow rate (ml/min) air gap length (cm) 1 nf1 63.0 nm ppsu/nmp; (29:71) 0/100 36 3 3 3.5 2 nf2 47.75 nm ppsu/nmp; (29:71) 0/100 36 1.5 3 3.5 3 nf3 65.74 nm ppsu/nmp; (25:75) 0/100 36 2.5 1.5 3.5 *according the membrane laboratory (university of technologybaghdad) fig. 5: photographic view of the nf1 membrane (sem mag) fig. 6: photographic view of the nf1 membrane thickness (sem mag) http://www.iasj.net/ removal of ni(ii), pb(ii), and cu(ii) from industrial wastewater by using nf membrane 92 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net experimental procedure figure 7 shows the schematic diagram of the nf process. pure water was used in the process for the purpose of measuring the flux coefficient and for cleaning before and after every test. after water preparation according to the required specifications and regulating the pressure, flow rate and other parameters as stated, the system is left to operate for at least 3 minutes to reach steady state (the time required to reach the steady state was early calculated). in the meantime permeate and rejected water return to the feed tank for the purpose of maintaining of the water concentration. after that time permeate water was collected in flask to test the amount of heavy metals to calculate the membrane rejection and determine the permeate flow rate to calculate the membrane flux. fig. 7: schematic diagram of the nf process, [4] results and discussion 1. performance of three types of nf membrane for heavy metals percentage removal and permeate flux figure 8 shows that the percentage removal of heavy metals at 1 bar were 71.2%, 68%, and 45, while the removal were 85%, 73%, and 35% at 4 bar of nf1, nf2, and nf3 respectively. figure 9 shows the differences among three types of nf membranes where the permeate fluxes were 15.5, 6, and 12.5 l/m 2 .hr at 1 bar , while the fluxes were 62, 31, and 49 l/m 2 hr at 4 bar of nf1, nf2, and nf3 respectively. fig. 8: effect of pressure on removal percentage of ni(ii) at different types of nf membrane (concentration = 100ppm, temperature=30 o c, ph=5.5, flow rate=30l/hr) http://www.iasj.net/ ahmed h. algureiri and yossor r. abdulmajeed -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 93 fig. 9: effect of pressure on permeate flux of ni(ii) ion at different types of nf membrane (concentration=100ppm, temperature=30 o c, ph=5.5, flow rate=30l/hr) 2. effect of different parameters on heavy metal removal and permeate flux for membrane system 2.1. effect of the concentration of feed the feed concentrations (50, 100, 150, 200 ppm) are chosen for all metals because almost these concentrations are present in most of the industrial wastewater. for nf system, the figure 10 shows that increasing of concentration for nickel (ii), lead (ii), and copper (ii) leads to decrease of removal percentage, with fixed parameters (pressure 3 bar, ph 5.5 and temperature 30 ºc); at 50 ppm concentration of heavy metals, the percentage of removal was 73%, 69%, and 54% for nickel (ii), lead (ii), and copper (ii) respectively; and at 200 ppm concentration of heavy metals, the removal decreased to 67%, 61%, and 45% for nickel (ii), lead (ii), and copper (ii) respectively. figure 11 shows the effect of the concentration on flux, where increasing in the concentration for nickel (ii), lead (ii), and copper (ii) led to decrease in flux. the flux was 15.4 l/m 2 .hr at 50 ppm concentration and it was 14.9 l/m 2 .hr at 200 ppm. this decrease in removal and flux for nf systems is because the increase in feed concentration leads to turbulence in flow at boundary layer that's leads to obstruction the pass ions across the pores, causing to decrease the removal and flux [12]. there is another explanation: the increasing in feed concentration leads to increase in the concentration of the negatively charged ions at the membrane surface, thus increasing shielding of negatively charged of the membrane. this results leads to reduce the repulsion forces on the positively charged ions and thus decreasing removal and flux [13]. fig. 10: effect of concentration on h.m. % removal for nf (pressure=1 bar, temperature=30 o c, ph=5.5, flow rate=1l/hr) fig. 11: effect of concentration on permeate flux for nf (pressure=4 bar, temperature=30 o c, ph=5.5, flow rate=1l/hr) the results are in a good agreement with kai yu wang, 2007. they reported the removals and permeate http://www.iasj.net/ removal of ni(ii), pb(ii), and cu(ii) from industrial wastewater by using nf membrane 94 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net flux of polybenzimidazole (pbi) nanofiltration hollow fiber membrane to cuso4 decrease with an increasing in metal ion concentration, [12], and with daniel james johnson, (2015) who has used nf270 membrane with 1000 mg/l concentration, pressure =4 bar, and ph = 1.5 ± 0.2. they reported the removal of copper ions is 90% at low concentrations, and decreased to 58% at the high concentration, while the removal was 99%, 89%, and 74% for cadmium, manganese, and lead respectively. 2.2. effect of pressure pressure is a very important parameter to operate the nf membrane. the membrane system has certain pressure difference, depending on the type of material that must be removed. figure 12 shows the effect of pressure on the removal of nickel (ii), lead (ii), and copper (ii) ions. the initial concentration was fixed as 100 mg/l, initial ph was adjusted at 5.5, and temperature was 30 ºc. from this figure it can be seen that the removal of metals increased from 71.2% ,67%, and 51 % of ni(ii), pb(ii) and cu(ii) respectively at 1 bar, to 85%, 78%, and 66 % of ni, pb and cu respectively at 4 bar. fig. 12: effect of pressure on h.m. removal for nf (concentration=100ppm, t=30 o c, ph=5.5, and feed flow=1l/hr) these results may be because the membranes incompletely prevent h.m. ions to be dissolved in feed water, therefore some h.m. passed through the membrane. when feed pressure is increased, these h.m. ions pass increased as water is pumped through the membrane at a high rate than h.m. can be transported. there is a certain limit and point on the curve which represents the increase in removals as pressure is increased. figure 13 shows that permeate flux increase linearly nearly from 15.2, 13, and 14 l/m 2 .hr at 1 bar, to 62, 57, and 60 l/m 2 .hr at 4 bar, for ni(ii), pb(ii), and cu(ii) with constant parameters (concentration 100 mg/l, temperature 30 ºc, ph 5.5, , and feed flow 30 l/hr). fig. 13: effect of pressure on permeate flux for nf (concentration = 100ppm, temperature=30 o c, ph=5.5, and feed flow=1l/hr) 2.3. effect of temperature figure 14, shows the effect of temperature on nickel (ii), lead (ii), and copper (ii) removal from aqueous solution by nf system. the effect of temperature of nf seen in the figure shows that the removal has been 66.5%, 64%, and 49% for nickel (ii), lead (ii), and copper (ii) respectively at 10ºc, and 72%, 68%, and 51% for nickel (ii), lead (ii), and copper (ii) respectively at 40 ºc. figure 15, shows the effect of temperature on permeate flux. the http://www.iasj.net/ ahmed h. algureiri and yossor r. abdulmajeed -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 95 values of permeate also increased clearly from 7, 7.5, and 6.8 l/m 2 .hr at 10 o c, to 21, 20, and 21.5 l/m 2 .hr at 40 o c, for ni(ii), pb(ii), and cu(ii) respectively. the flux of permeate is increase with temperature increase, because the diffusivity of water increases and its viscosity decreases. the increasing of temperature caused an increase in pore size of the polymeric membrane [14]. fig. 14: effect of temperature on h.m. % removal for nf (flow rate=1 l/hr, h.m. concentration 100 ppm, pressure= 1 bar, and ph 5.5) fig. 15: effect of temperature on permeate flux for nf membrane (concentration 100 ppm, pressure =1 bar, and ph=5.5, flow rate=1l/hr) 2.4. effect of ph removal of h.m. (ni(ii), pb(ii), and cu(ii)) at different ph (2 – 5.5) is presented in figure 16. it can be noticed from the figure that the h.m. removal values increased from 54%, 51%, and 34% at ph 2, to 71.2%, 67%, and 51% at ph 5.5 for ni(ii), pb(ii), and cu(ii) ions respectively. fig. 16: effect of ph on h.m. removal for nf membrane, (concentration = 100 ppm, pressure= 1bar temperature = 30 o c, and, and flow rate= 1 l/hr) the highest value of permeate flux was 15.2, 14.9, and 15 l/m 2 .hr at ph 5.5, and the lowest value was 14.2, 14, and 14.3 l/m 2 .hr at ph 2, for ni(ii), pb(ii), and cu(ii) respectively, as it was shown in figure 17. the increase in removal can be attributed to the fact that the membrane is positively charged at ph < 7.0, but the positive charge decreases with increasing ph value, resulting in a low permeate of the anions; therefore in order to maintain the electro neutrality of the permeate solution, the removal of the ni(ii), pb(ii), and cu(ii) ions increases, and the permeate flux increase also, [15], [16]. fig. 17: effect of ph on permeate flux for nf, (flow rate=1l/hr, h.m. concentration= 100 ppm, pressure=1 bar, and temperature=30 o c) http://www.iasj.net/ removal of ni(ii), pb(ii), and cu(ii) from industrial wastewater by using nf membrane 96 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net laura a. richards et al. (2010) reported that the removal of nickel ions across nf membrane is dependent on ph, where increasing the concentration of sodium sulphate in the feed solution lead to increase the ph of the feed solution [17]. the positive charges force on the membrane will be lower as the ph increases towards the surface of the membrane, this leads to low nickel removal. 2.5. effect of feed flow rate the increase in feed flow rate leads to increase the flux and more removal of heavy metals, because of removal of fouling layer from the surface of membrane, provided that it does not exceed a certain extent because values more than the limit lead to a lack of capacity of the filter membrane and possibly damage the membrane. this depends on construction and the mechanical strength of the membrane. figures 18 shows increasing feed flow rate led to decrease in permeate concentration, for h.m across nf membrane. the removal percentage were 71.2%, 67%, and 51% at feed flow rate 1 l/hr, which increased to 73.4%, 69.9%, and 56.5% at feed flow rate 4 l/hr for nickel (ii), lead (ii), and copper (ii) respectively. figure 19, shows the effect of increasing of feed flow rate on permeates flux for all metals, the permeate fluxes are 15.2, 15.1, and 15.1 l/m 2 .hr at feed flow rate 1 l/hr. it increased to 41, 39, and 37 l/m 2 .hr at feed flow rate 4 l/hr for nickel (ii), lead (ii), and copper (ii) respectively. the increase in the feed flow rate reduces concentration polarization value due to increase in turbulence near the membrane resulting in decreasing in the boundary layer thickness and solute concentration [18], [19], [20]. these results are in close agreement with j. fernandez, (2010), who noticed the permeate flow will increase with increase in the feed flow rate or the cross flow velocity. that is when cross flow velocity is 0.2 cm/s, the permeate flux is 0.80 x 10 6 m 3 /s·m 2 ; and when cross flow velocity changes to 0.7 and 1.7 cm/s, the permeate flux is 1.08 and 1.39 x 10 -6 m 3 /s·m 2 , respectively. at the end of the run, when velocity returns to the initial value (0.2 cm/s), permeate flux returns to 0.80 x 10 -6 m 3 /s·m 2 [21]. fig. 18: effect of feed flow rate on h.m. ions removal for nf membrane (concentration=100 ppm, pressure= 1 bar, temperature=30 o c, and ph=5.5) fig. 19: effect of flow rate on permeate flux for nf membrane (concentration=100 ppm, pressure= 1 bar, temperature=30 o c, and ph=5.5) conclusions the conclusions drawn from this work are: 1. the nf membranes are very efficient to remove heavy metals http://www.iasj.net/ ahmed h. algureiri and yossor r. abdulmajeed -available online at: www.iasj.net ijcpe vol.18 no.1 (march 2017) 97 from industrial wastewater which produced for many industries. 2. h.m ions removal from industrial wastewater and permeability flux by nf membrane is proportional to applied pressure, ph, solution temperature and feed flow rate, but it is inversely proportional to feed concentration. recommendations for future work the following recommenditions can be helpful for future work: 1. present work can be extended to study other conditions such as adding some chemical materials that help to extend the life of the membrane. 2. the study of new types of nf membrane for the purpose of improving the efficiency of the membrane in terms of production and removal. 3. this work can be extended to study the removal of other types of pollutants such as organic, inorganic and macroscopic contaminants from industrial waste water by nf membrane. 4. this work can be extended to study a comparative between the ro and nf membranes in terms of energy consumption. references 1. surd gergely, arsenic "removal from drinking water by nanofiltration", doctoral (phd) thesis, new scientific results, (2001). 2. who, international year of fresh water. general assembly resolution a/res/ss/196, (2005). 3. barakat m. a. " new trends in removing heavy metals from waste water ", arabian journal of chemistryvolume 4, issue 4, pages 361–377, (2011). 4. ahmed h. algureiri,"experimental study on the influence of operating conditions on the removal of heavy metals from industrial wastewater", a thesis of msc. engineering alnahrain university, baghdad (2016). 5. al-jlil s.a. "removal of heavy metals from industrial wastewater by adsorption using local bentonite clay and roasted date pits in saudi arabia", trends applied sci. res., 5: pages138-145, (2010). 6. fenglian fu, and qi wang, "removal of heavy metal ions from wastewaters" a review, journal of environmental management, vol. 92 no. 3, pages 407-418, (2011). 7. junwenlv, kai yu wang, and taishung chung, "investigation of amphoteric polybenzimidazole (pbi) nanofiltration hollow fiber membrane for both cation and anions removal, page 332, (2008). 8. dow-filmtec membranes manufacturer company, product information catalog, (2012). 9. bhattacharyya d., and williams m., "theory reverse osmosis", membrane handbook, pages 269280, new york, (1992), cited in williams, (2003). 10. haynes w. m.,"crc handbook of chemistry and physics", crc press/taylor and francis, boca raton, fl, 95th edition, (2015). 11. coursey j. s., schwab d. j., tsai j.j., and dragoset r. a., "atomic weights and isotopic compositions", (version 3.0), 2010, national institute of standards and technology, gaithersburg, md,( 2014). 12. murthy z.v.p., and latesh chaudhari, "application of nanofiltration for the rejection of nickel ions from aqueous solutions and estimation of membrane transport parameters", journal of hazardous materials volume 160, issue 1, 15, pages 70–77, (2008). 13. gaojie, "nanofiltration membrane for lead removal", a http://www.iasj.net/ http://www.sciencedirect.com/science/journal/18785352 http://www.sciencedirect.com/science/journal/18785352 http://www.sciencedirect.com/science/journal/18785352/4/4 http://www.nist.gov/pml/data/comp.cfm http://www.nist.gov/pml/data/comp.cfm http://www.nist.gov/pml/data/comp.cfm http://www.sciencedirect.com/science/journal/03043894/160/1 http://www.sciencedirect.com/science/journal/03043894/160/1 removal of ni(ii), pb(ii), and cu(ii) from industrial wastewater by using nf membrane 98 ijcpe vol.18 no.1 (march 2017) -available online at: www.iasj.net thesis of msc. engineering national university of singapore, (2014). 14. lee i. , kuan y. and chern j., “ equilibrium and kinetics of heavy metal ion exchange”, journal of the chinese institute of chemical engineers, vol. 38, pages 71-84 (2007). 15. abhaga r.m., wanib k.s., patilc v.s., pangarkara b.l., and parjane s.b. "nanofiltration for recory of heavy metal ions from waste water –a review", international journal of research in environmental science and technology, pages 2934, (2013). 16. amir abbas izadpanah , and asgharjavidnia, "the ability of a nanofiltration membrane to remove hardness and ions from diluted seawater", water, volume 4, issue 2, (2012). 17. laura a. richards, bryce s. richards, and andrea i. schäfer "salt and inorganic contaminant removal by renewable energy powered nanofiltration/reverse osmosis", heriot-watt university, edinburgh, united kingdom submitted to journal of membrane science , vol 369, no. 1-2, pages 188-195., (2010). 18. abou-nemeh i., and van peteghem a. p., "membrane recycling in the liquid surfactant membrane process", (1993). 19. barakat m.a. " removal of cu (ii), ni (ii) and cr (iii) ions from wastewater using complexationultrafiltration technique", journal of environmental science and technology, volume 1, issue 3, pages 151-156, (2008). 20. velinjanimthethwa," investigation of polyethersulfone (pes) hollow fiber membrane for the treatment of acid mine drainage", johnson matthey technology review, (2014). 21. fernandez j. and sempere," experimental study of concentration polarization in across flow reverse osmosis system using holographic", desalination volume 257, p 36-45, issues1-3, (2010). http://www.iasj.net/ http://pubs.acs.org/action/dosearch?contribstored=abou-nemeh%2c+i. http://pubs.acs.org/action/dosearch?contribstored=van+peteghem%2c+a.+p. http://pubs.acs.org/action/dosearch?contribstored=van+peteghem%2c+a.+p. http://www.scialert.net/jindex.php?issn=1994-7887 http://www.scialert.net/jindex.php?issn=1994-7887 http://www.scialert.net/jindex.php?issn=1994-7887 available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.22 no.1 (march 2021) 15 – 20 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: nuha muhsen ali, email: onelegendary20a@gmail.com , name: tariq mohammed naife, email: tariq.mohammed@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. removal of vanadium and nickel ions from iraqi atmospheric residue by using solvent extraction method nuha muhsen ali and tariq mohammed naife university of baghdad, chemical engineering department, baghdad, iraq abstract iraqi crude atmospheric residual fraction supplied from al-dura refinery was treated to remove metals contaminants by solvent extraction method, with various hydrocarbon solvents and concentrations. the extraction method using three different type solvent (n-hexane, n-heptane, and light naphtha) were found to be effective for removal of oil-soluble metals from heavy atmospheric residual fraction. different solvents with using three different hydrocarbon solvents (n-hexane, n-heptane, and light naphtha) .different variables were studied solvent/oil ratios (4/1, 8/1, 10/1, 12/1, and 15/1), different intervals of perceptual (15, 30-60, 90 and 120 min) and different temperature (30, 45, 60 and 90 °c) were used. the metals removal percent were found depending on the yield of asphaltene. the solvent-oil ratio had important effects on the amount of metal removal. the metals removal was increased at increasing temperatures from 30 to 90 0 c increases the metal ion precipitated. the highest ni precipitated was 79.23 ppm using heptane at 90 0 c while for v the highest value was 64.51 ppm using also heptane at 90 0 c, while the mixing time decreased metals removal. with increasing asphalt yield, the removal of metal was more selective. among the solvents used in the extraction treatment method, the highest ni precipitated was 76 ppm using hexane at 150 ml solvent and showed the most promising results. increasing mixing time increases metals removal for v, the highest value was 65.51 ppm using either heptane or light naphtha. the highest ni precipitated was 78 ppm using heptane at 120 min while for v the highest value was 67 ppm using either heptane or light naphtha after 120 min. keywords: metal removal, atmospheric residue, deasphalting process, solvent extraction received on 28/11/2020, accepted on 11/02/2021, published on 30/03/2021 https://doi.org/10.31699/ijcpe.2021.1.2 1introduction in response to the global energy consumption needed, the oil refining industry has been developing new ways to overcome asphalt-bearing streams and metal-containing strips with growing efforts and resources [1]. crude oils normally have various quantities of impurities, not metal and metal. non-metallic impurities typically include nitrogen, sulfur, and oxygen; nickel, vanadium, iron, sodium, copper, zinc and arsenic are usually metallic impurities [1]. deasphalting is a traditional selective extraction process, which is designed to separate by a suitable solvent a portion suited for deasphalted oil conversion (dao) and a portion suitable for thermal conversion (pitch)[2]. the strong atmospheric residue is asphalt that depends on the form of solvent that is used [3]. the unit throughput is limited by a growing number of asphalt compounds in the feed. asphaltene can also contain a considerable amount of sulfur, nitrogen, and metals, and/or fraction thereof. the majority of the raw oil content of the refineries can be concentrated and/or collected in feed for the hydroconversion units [4]. solvent deasphaltation is a commercially performed method for extracting asphalt from the heavy oil from the ambient and/or vacuum towers. the solvent deasphalt unit requires high capital costs and high operating costs for solvent recycling [5]. solvent deasphalting (sda) is a special method in which the remains are broken into a low contaminant deasphalted oil (dao) rich in paraffin, using the molecular weight (density) rather than the boiling spot. it is a relatively cheap method that has reasonable versatility to achieve a wide variety of dao qualities[6]. a solvent (typically c3–c7) is employed and retrieved by supercritical recovery methods from both substance streams (atmospheric and vacuum distillation)[7]. during the solvent deasphalting phase, the solvent solution is solvent dependent on the application of paraffin (c4–c7) solvents (butane, pentane, hexane, and heptane). the insoluble pitch is precipitated as asphalt from the mixed feedstock. the extractor separates the deasphalted oil phase from the pitch phase. the extractor is designed to separate the two phases efficiently and reduce contaminant entry during the dao process [8]. as a result of its low metal content (ni and v), dao is usually used as the fluid catalytic fcc cracker or a hydrocracker feedstock. sda technology can be used in many ways that allow the refiner to progressively move towards the development of zero fuel oil residues over time[9]. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:onelegendary20a@gmail.com mailto:tariq.mohammed@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2021.1.2 n. m. ali and t. m. naife / iraqi journal of chemical and petroleum engineering 22,1 (2021) 15 20 16 most of the metal pollutants are considered to be found in the production of waste crude oil as inorganic sulfides, oxides, and water-soluble constituents. the remaining metals are commonly concentrated in the residual fractions of oil as relatively thermally stable, oil-soluble organometallic structures such as metal porphyrins and derivatives [10, 11, and 12]. now the toxic effects of petroleum metals have been recognized. the metals do not contaminate the product only, but the metals contaminate the products, but even the metal chelates cause catalytic toxicity and excessive gas and coke formation. the corrosion of fuel oil burning facilities also causes significant harm to vanadium and nickel along with sodium [13]. the high levels of metal of petroleum residues currently need expensive improvements, both by high hydrogen adjustment costs and by high carbon discharge losses. if metal was extracted before the conventional hydrocracking process in a pretreatment stage, the residues could be improved more economically [14, 15]. the work aims to study different conditions such as asphaltene yield, time, solvent types, solvent ratio, and temperature on the removal of vanadium and nickel ions from iraqi heavy crude oil. 2experimental work this study discusses the removal of metals from the residual fraction using a relatively solvent extraction method. the solvents used are (n-hexane, light naphtha, and n-heptane) in this study, different solvent/oil ratios (4/1, 8/1, 10/1, 12/1, and 15/1), different perceptual periods (15, 30, 60, 90, and 120 min) and different temperatures (30, 45, 60 and 90 ° c). the sample of atmospheric residue from the al-dura refinery was treated with a variety of chemical solvents to remove metals (ni, v). 2.1. materials three types of petroleum solvents were used in this study and the atmospheric residue: a. atmospheric residue table 1 displays the characteristics of iraqis atmospheric petroleum-residues supplied from al-dura refinery oil residues. table 1. the properties of atmospheric oil residue characteristics value specific gravity at 15.6/15.6 0 c 0.9705 api gravity 14.9 kinematic viscosity, c.st.at 100 0 c 32.73 sulfur content, wt.% 0.5 flashpoint 0 c 190 vanadium content,wt. ppm 86.14 nickel content,wt. ppm 79.6 b. hydrocarbon solvents b1n-hexane n-hexane with a purity of 99% was supplied from merck b2 n-heptane n-heptane with purity 99% was supplied from (poch sa) company. b3 light naphtha light naphtha with 99% purity was supplied from the aldura refinery. 2.2. experimental laboratory setup the deasphalting laboratory device represents in fig. 1 which is used to measure the metal removal consists of mixing of oil residuals (and solvents) in two-neck flask glasses with solvent /oil ratio of 4/1, 8/1, 10/1, 12/1, and 15/1, round flask put in a magnet heating stirrer with a speed of 450 to 120 rpm and a temperature range from 30 to 220 o c, and a perceived length of 15, 30, 60, 90 and 120 min. fig. 1. the de asphalting apparatus and its scheme n. m. ali and t. m. naife / iraqi journal of chemical and petroleum engineering 22,1 (2021) 15 20 17 the sample was transferred to a 5 mm hg vacuum filter pump represented in fig. 2. on a filter paper surface to which it has been weighted in size, the solvent and the residual filtrate persist through the flask and asphalt. fig. 2. filtration unit setup to measure the metal content of the sample, one gram was dried and treated with 750 0 c in the oven for 30 min then the sample was cooled at room temperature. after cooling the sample was mixed with 5 ml of concentrated hydrochloric and nitric acid each and then placed in the oven at 150 0 c for 15 min after sample preparation it was taken to 25 ml bottle and the sample is ready to be tested for metal content using analytikjena aa nov350. 3 results and discussion 3.1. effect of solvent type the results of different parameters on metals removal are shown in fig. 3 to 14. the effective parameters of the process included temperature, solvent to oil ratio, duration time, and asphaltene yield on metals content (vanadium and nickel). fig. 3 and fig. 4 show the effect of temperature on the metal ion for both ni and v where the increase of temperature from 30 to 90 0 c increases the metal ion precipitated. the highest ni precipitated was 79.23 ppm using n-heptane at 90 0 c while for v the highest value was 64.51 ppm using also heptane at 90 0 c fig. 5 and fig. 6. fig. 3. effect of temperature on ni metal ion using different solvent at 450 rpm, 15/1 solvent to oil ratio, and 120 min fig. 4. effect of temperature on v metal using different solvent at a different temperature at 450 rpm, 15/1 solvent to oil ratio, and 120 min fig. 5. effect of solvent to oil ratio on ni metal ion using different solvent at 450 rpm, 90 o c, and 120 min the effect on the reduction of vanadium and nickel respectively of the increase in the solvent ratio is demonstrated. in this case, the rising proportion of solvents contributed to a greater decrease in metals due to increased asphalt removal. since the paraffin solvent capable of soluble oil paraffin, it cannot solubly asphalt is the solvent was able to enhance the properties of dao [16]. the highest ni precipitated was 76 ppm using hexane at 150 ml solvent while for v the highest value was 65.51 ppm using either heptane or light naphtha. fig. 6. effect of solvent ratio on v metal ion using different solvent at 450 rpm, 90 o c, and 120 min n. m. ali and t. m. naife / iraqi journal of chemical and petroleum engineering 22,1 (2021) 15 20 18 the effect of treatment time with different solvent types was also been studied for metal ion removal. fig. 7 shows the ni removal with time and in general as time increases the metal concentration in the process also increases. the reason for this phenomenon is the more mixing time for the solvent to penetrate the heavy composition of the asphaltene allowing the metal to precipitate [17]. the highest ni precipitated was 78 ppm using heptane at 120 min while for v the highest value was 67 ppm using either heptane or light naphtha after 120 min. fig. 7. effect of duration time on ni metal ion using different solvent at 450 rpm, 90 o c, and 15/1 solvent to oil ratio fig. 8. effect of duration time on v metal ion using different solvent at 450 rpm, 90 o c, and 15/1 solvent to oil ratio fig. 9. effect of asphaltene yield on ni metal ion using heptane. at 450 rpm, 90 o c and 15/1 solvent to oil ratio, 120 min fig. 10. effect of asphaltene yield on ni metal ion using hexane at 450 rpm, 90 o c, and 15/1 solvent to oil ratio, 120 min fig. 11. effect of asphaltene yield on ni metal ion using light naphtha. at 450 rpm, 90 o c and 15/1 solvent to oil ratio, 120 min fig. 12. effect of asphaltene yield on v metal ion using heptane at 450 rpm, 90 o c, and 15/1 solvent to oil ratio, 120 min changes in the asphaltenes yield influence metal removal because such heteroatoms concentrate and isolate the dao low heteroatoms formed in asphalt particles. figures 9 to 14 show an improvement in asphaltene production in ni and vanadium removal. the increase in asphalt yields tends to contribute to the removal of high metals. the results showed that the decomposition process was selective for the removal of metals as well. n. m. ali and t. m. naife / iraqi journal of chemical and petroleum engineering 22,1 (2021) 15 20 19 fig. 13. effect of asphaltene yield on v metal ion using hexane at 450 rpm, 90 o c and 15/1 solvent to oil ratio, 120 min fig. 14. effect of asphaltene yield on v metal ion using light naphtha at 450 rpm, 90 o c, and 15/1 solvent to oil ratio, 120 min 4 conclusions for the solvent extraction method in the asphaltene separation process, all solvents used were highly efficient on metal removal. the metal removal depended on the type of solvent and increased when the solvent chain length decreased. the solvent to oil ratio had a strong effect on the metal precipitated. the output of metal was increased at decreasing temperatures and the maximum output was obtained at 90 ̊c. the removal of metals was more selective as the asphaltene yield increased. maximum efficiency of deasphalting, with n-heptane as the solvent, ni precipitated was 79.23 ppm using heptane at 90 0 c while for v the highest value was 64.51 ppm using also heptane at 90 0 c. nomenclatures and abbreviations parameter meaning unit v vanadium ppm ni nickel ppm dao deasphalted oil ml sda solvent deasphalting wt. % fcc fluid catalytic cracking ppm part per million references [1] ali, m. f., bukhari, a., and salim, m. "trace metals in crude oils from saudi arabia". ind. eng. chem. prod. res. dev. 22, 1983, pp.691–695. [2] emil d., richard f., "natural bitumen and extra-heavy oil", world energy council. isbn 0-946121-262007, pp. 123–140. [3] ali, m. f., and abbas, s. "a review of methods for the demetallization of residual fuel oils". fuel process. tech. 87:2006. pp.573–584. [4] v. valkovic. "trace elements in petroleum // petroleum publishing company". oklahoma usa. – 1978. pp.8689. [5] kalichevsky, v. a., and stagner, b. a. " chemical refining of petroleum". new york: reinhold publishing, 1942. [6] t.f. yen, et all. "the role of trace metals in petroleum", ann arbor science publishers, ann arbor, mi vol. 13. 1975, pp. 403-405. [7] v.a. kalichevsky, et all “chemical refining of petroleum", reinhold publishing corp., new york, usa. –1942. – pp. 45-311. [8] m. f. ali, s. abbas. "a review of methods for the demetallization of residual fuel oils" fuel process. tech. vol. 87-2006. pp 573–584. [9] j.ancheyta, j.g. speight. "hydroprocessing of heavy oils and residua" chemical industries., new york: crcpress, vol.180 , 2007.pp. 376 [10] premuzic e. t. and lin m. s., “212th national acs meeting induced biochemical interactions in crude oils”, orlando, fl. august 18-22, 1996. [11] eckermann b. and vogelpohl a., “deasphaltization and demetalling of heavy crude olis and distillation residues with co2”, chemical engineerring and technology. v13, 1990, pp.258-264. [12] mendes m. f., ferreira c. z. and pessoa f. l. p., “deasphaltion of petroleum using supercritical propane”, 2nd mercosur congress on chemical engineering, enpromer, costa verde – brasil, 2005. [13] r. kaiser abdulmajeed, “new viscosity correlation for different iraqi oil fields”, ijcpe, vol. 15, no. 3, pp. 71-76, sep. 2014. [14] s. a. mohammed and s. d. maan, “the effect of asphaltene on the stability of iraqi water in crude oil emulsions”, ijcpe, vol. 17, no. 2, pp. 37-45, jun. 2016. [15] r. hasan and a. a. al-haleem, “modifying an equation to predict the asphaltene deposition in the buzurgan oil field”, ijcpe, vol. 21, no. 4, pp. 49-55, dec. 2020. [16] aldridge c., bearden j., “studies on heavy hydrocarbon conversions”, exxon research and development laboratories; 1986. [17] edward j. houde, michael j. mcgrath, “when solvent deasphalting is the most appropriate technology for upgrading residue”, idtc conference, london, england, february 2006. https://pubs.acs.org/doi/pdf/10.1021/i300012a034 https://pubs.acs.org/doi/pdf/10.1021/i300012a034 https://pubs.acs.org/doi/pdf/10.1021/i300012a034 http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.478.9340&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.478.9340&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.478.9340&rep=rep1&type=pdf https://www.sciencedirect.com/science/article/pii/s037838200600049x https://www.sciencedirect.com/science/article/pii/s037838200600049x https://www.sciencedirect.com/science/article/pii/s037838200600049x https://www.osti.gov/biblio/6539738 https://www.osti.gov/biblio/6539738 https://www.osti.gov/biblio/6539738 https://www.sciencedirect.com/science/article/pii/s037838200600049x https://www.sciencedirect.com/science/article/pii/s037838200600049x https://www.sciencedirect.com/science/article/pii/s037838200600049x https://books.google.iq/books?hl=en&lr=&id=rtutf-wbjswc&oi=fnd&pg=pp1&dq=%5b9%5d%09j.ancheyta,+j.g.+speight.+%22hydroprocessing+of+heavy+oils+and+residua%22+chemical+industries.,+new+york:+crcpress,+vol.180+,+2007.pp.+376&ots=dgk17b21xr&sig=d5hf8xhtpmzzc4tgf523tedp-o4&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=rtutf-wbjswc&oi=fnd&pg=pp1&dq=%5b9%5d%09j.ancheyta,+j.g.+speight.+%22hydroprocessing+of+heavy+oils+and+residua%22+chemical+industries.,+new+york:+crcpress,+vol.180+,+2007.pp.+376&ots=dgk17b21xr&sig=d5hf8xhtpmzzc4tgf523tedp-o4&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=rtutf-wbjswc&oi=fnd&pg=pp1&dq=%5b9%5d%09j.ancheyta,+j.g.+speight.+%22hydroprocessing+of+heavy+oils+and+residua%22+chemical+industries.,+new+york:+crcpress,+vol.180+,+2007.pp.+376&ots=dgk17b21xr&sig=d5hf8xhtpmzzc4tgf523tedp-o4&redir_esc=y#v=onepage&q&f=false https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.270130135 https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.270130135 https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.270130135 https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.270130135 https://www.researchgate.net/profile/marisa-mendes/publication/238090809_deasphaltation_of_petroleum_using_supercritical_propane/links/0c960536a192c10ff0000000/deasphaltation-of-petroleum-using-supercritical-propane.pdf https://www.researchgate.net/profile/marisa-mendes/publication/238090809_deasphaltation_of_petroleum_using_supercritical_propane/links/0c960536a192c10ff0000000/deasphaltation-of-petroleum-using-supercritical-propane.pdf https://www.researchgate.net/profile/marisa-mendes/publication/238090809_deasphaltation_of_petroleum_using_supercritical_propane/links/0c960536a192c10ff0000000/deasphaltation-of-petroleum-using-supercritical-propane.pdf https://www.researchgate.net/profile/marisa-mendes/publication/238090809_deasphaltation_of_petroleum_using_supercritical_propane/links/0c960536a192c10ff0000000/deasphaltation-of-petroleum-using-supercritical-propane.pdf https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/290 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/290 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/290 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/80 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/80 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/80 https://doi.org/10.31699/ijcpe.2020.4.6 https://doi.org/10.31699/ijcpe.2020.4.6 https://doi.org/10.31699/ijcpe.2020.4.6 https://doi.org/10.31699/ijcpe.2020.4.6 n. m. ali and t. m. naife / iraqi journal of chemical and petroleum engineering 22,1 (2021) 15 20 20 النفط الجوي العراقي باستخدام طريقة االستخالص إزالة أيونات المعادن من متبقي بالمذيبات طارق محمد نايفنهى محسن علي داود و قسم الهندسة الكيمياوية -جامعة بغداد الخالصة تمت معالجة المتبقي من برج التقطير الجوي للخام العراقي المزود من مصفى الدورة إلزالة الملوثات المعدنية بطريقة االستخالص بالمذيبات. تم استعمال طريقة االستخالص باستخدام ثالثة أنواع مختلفة من المذيبات 10/1، 8/1، 4/1ت بنسب مذيبات / الزيت ))الهكسان و الهبتان والنافثا الخفيفة(. تم استخدام كميات مذيبا و 60، 45، 30دقيقة( ودرجات حرارة ) 120و 90، 60-30، 15( ، وفترات خلط )15/1، 12/1، درجة مئوية. تم ايجاد ان نسبة إزالة المعادن تعتمد على ناتج األسفلتيين. كان لنسبة المذيبات إلى الزيت 90 درجة 90إلى 30دن المزالة. زادت نسبه إزالة المعادن عند رفع درجات حرارة من تأثيرات مهمة على كمية المعا جزء في المليون باستخدام 79.23مئوية مما يؤدي إلى زيادة ترسيب أيون المعدن. كان أعلى ترسب نيكل لهبتان أيًضا جزء في المليون باستخدام ا 64.51درجة مئوية بينما كانت أعلى قيمة لـلفناديوم 90الهبتان عند 76درجة. من بين المذيبات المستخدمة في طريقة االستخالص ، كان أعلى ترسيب هو النيكل بتركيز 90عند جزء 65.51مل من المذيب. بينما كانت أعلى قيمة لـلفناديوم 150جزء في المليون باستخدام الهكسان عند في المليون باستخدام الهبتان أو النافتا الخفيفة. دقيقة بينما أعلى قيمة لـلفناديوم 120جزء في المليون باستخدام الهبتان عند 78أعلى ترسب نيكل كان دقيقة. 120جزء في المليون باستخدام الهبتان أو النافتا الخفيفة بعد 67كانت لمذيباتالكلمات الدالة: إزالة المعادن ، متبقي النفط الجوي ، عملية ازالة األسفلت واالستخالص با available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.20 no.3 (september 2019) 75 – 79 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: ayad a.alhaleem a.alrazzaq , email: ayadah62@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. development of east baghdad oil field by clusters of horizontal wells ayad a.alhaleem a.alrazzaq engineering college-university of baghdad abstract there are varieties of reasons lead for drilling horizontal wells rather than verticals. increasing the recovery of oil, especially from thin or tight reservoir permeability is the most important parameter. east baghdad oil field considered as a giant field with approximately more than 1billion barrel of a proved reserves accompanying recently to low production rate problems in many of the existing wells. it is important to say that presence of of horizontal wells in east baghdad field especially by converting some of already drilled wells by re-entry drilling horizontal sections may provide one of best solutions for the primary development stage in east baghdad field which may be followed by drilling new horizontal wells or using multilateral wells. advance software (well test/fast) has been used to convert the production data for the already drilled vertical wells to horizontals to simulate the productivity. it can be concluded that no measurements available for the ratio of anisotropy (kv/kh); in east baghdad oil field therefore, the wells productivity has been estimated using wide range of anisotropy ratios that will help the field operator to determine exactly wells productivity. moreover, it helps to recommend the effectiveness of applying hydraulic fracturing in improving horizontal well productivity. the results show that it could be used well eb-32 as a re-entry horizontal well with an optimum section length of 1500-2000ft wich give the best production rate. the same result could be stated for eb-10 with somewhat higher productivity than eb-32. keywords: horizontal wells, productivity, vertical permeability, reentry drilling wells received on 19/03/2019, accepted on 27/07/2019, published on 30/09/1029 https://doi.org/10.31699/ijcpe.2019.3.10 1introduction horizontal drilling represents a tool to reduce drilling operations costs of an oil field due to two concerns; first improving formation production, and second the cost of rig operations and mobilization will be minimized because drilling more than one well in the same land or platform ‎[1]. in other words, horizontal wells are of great interest in petroleum industry because they provide an attractive means for improving both production rate and recovery efficiency ‎[2]. it was found that the factors (well length, permeability ratio, reservoir thickness, skin factor, drainage radius and well radius) affect the pressure drop between the well bore and the reservoir which affect the productivity index in horizontal wells ‎[3]. also an analytical method could be applied in any position within the entire reservoir area to provide the tilt of originally oil-water contact in all directions in horizontal wells ‎[4]. east baghdad oil field was discovered by seismic survey which was carried in 1960 and 1974. the first well was drilled and completed in the south part of the field in 1975 and till now already drilled and completed many exploration delineation and production wells in different parts of the field. east baghdad field has actually multi reservoirs, main of them are tanuma, khasib and zubair with different grades of crude oil 21 23and 35 api in zubair formation ‎[5]. east baghdad oil field considered as giant field with proved reserves estimated at more than11billion barrels and probable reserves to about 17 billion barrels. the geological structure of east baghdad oil field is very complicated due to presence of many faults. in the same time the field is locating under treated agriculture lands and urban areas .the total area of the field is about 660 km 2 . in 1985 diction was taken to develop the field by clusters and directional wells .thirteen clusters 700 by 800 m and 49 emergency drilling locations were fixed and reserved to develop that part of the field to reach production rate at 120000 bbl per day. the development of the field was planned to do by stages and the first stage was done to produce 20000 barrel per day and that stage called the pilot project and the selected area was in rashdya region. the project was completed and the facilities were commissioned in aug 1990. the average grade of produced crude was 21-23 api from two reservoirs tanuma and khasib by 21 producers and 6 injector's wells with dual completions. https://doi.org/10.31699/ijcpe.2019.3.10 a. a.alhaleem a.alrazzaq / iraqi journal of chemical and petroleum engineering 20,3 (2019) 75 79 67 eighteen wells were drilled directionally from two clusters by modified skid mounted rigs moved by jacking system on skidding rails gantry slot ‎[6]. one's decision was taken to continue the development of east baghdad oil field by clusters and directional wells, it is advisable to drill and complete some or reentry drilling horizontal wells for economic reasons and reduction the number of wells. according to the last study done by reservoir engineering department shows that upper khasib has six layers with total thickness about 70 m and these layers are connected between them vertically ‎[6]. 2reservoir selection consider the thicker interval with total thickness of 25 m which is the main productive zone of sw=0.37, so according to that it is recommended to drill the first horizontal well to produce from this layer of upper khasib formation. it is possible on lateral horizontal drilling to produce from multilayer or more than one reservoir. actually, horizontal drilling recently used in development of iraqi oil fields due to high production rates presence of thick reservoirs. the major purpose of drilling horizontal wells is to enhance reservoir contact and there by enhance well prod activity also in reservoirs with water and gas coning problems; horizontal wells have been used to minimize conning problems ‎[7]. in general, a horizontal well is drilled parallel to reservoir bedding plane ‎[8], that means a horizontal well is a well which intersects the reservoir bedding plane at 90 degree. a typical horizontal well project is different from a vertical well project because productivity of a well depends upon the well length. 3selection horizontal well type there are five types of horizontal wells that have evolved for reasons of hydrocarbon reservoir requirements or to designate the equipment required to drill the wells. the types of wells have become known as ‎[8],‎[9]: 1long – radius 2mediumradius 3short – radius 4tangent 5combination in this study, it is recommended to choose the first type (longradius) because the depth of productive zone (2000-2200m) allows drilling such types of drilling. the builds section it takes longer time than the other types but the long-radius wells are usually drill with standard directional equipment while short – radius wells require an assortment of special equipment. vertical well drains cylindrical volume whereas horizontal well drains an ellipsoid; three-dimensional ellipse. since, horizontal wells expectable to drain larger reservoir volume than vertical wells ‎[10]. 4work development advance software technology (f.a.s.t well test) (appendix a) has been used to convert the production data for the already drilled vertical wells to horizontals to simulate the productivity ‎[11]. the converted horizontal wells have been simulated to oil production assuming the cases of (1nocommunication exist between the layers, 2degree of communication exist between the layers). the simulated results show that the first assumption led to incorrect results, while the second assumption led to give the most reliable results. two vertical wells eb-10 and eb-32 have been selected to be converted to horizontal wells and simulated for different lateral section lengths (260-3000 ft). moreover two values of skin factor (s=0 and s= -4) have been processed to analyze the sensitivity of simulation the hydraulic fracturing in production increment. it can be stated that no measurements available for the ratio of anisotropy (kv/kh); therefore the wells productivity has been estimated using wide range of anisotropy ratios that will help the field operator to determine exactly wells productivity soonest getting this value. moreover, it helps to determine the effectiveness of hydraulic fracturing in improving horizontal well productivity. 5results and discussion fig. 1 shows the effect various lateral horizontal lengths (500-2500 ft) for different estimated (kv/kh) ratios for well eb-32. fig. 1. production /rate versus (kr) for different lateral section length. well no. (32) also, it could be noticed that increasing well lateral section in low (kv/kh) ratio has little effects in increasing well production rate. fig. 2 shows the variation of the productivity index versus different ratios of (kv/kh) with different lateral section lengths (well eb-32). a. a.alhaleem a.alrazzaq / iraqi journal of chemical and petroleum engineering 20,3 (2019) 75 79 66 fig. 2. productivity index versus (kr) for different lateral section length (le.) well no. (32) in the same trend, fig. 3 shows the productivity index versus lateral section lengths for different kr ratios for well eb-10. it could be noticed that the well eb-32 requires higher flowing pressure in lateral section length less than 1500 ft especially in low (kv/kh) ratios as shown in fig. 4. a comparison for the productivity index versus lateral section length for the two wells has been made shown in fig. 5. the results show the same trend for both wells with some what little higher values for well eb-10. the production capacity for the well eb-32 is also simulated for two simulation values of (s=0 and s= -4) for various vertical to horizontal permeability ratios (kr) as shown in fig. 6 and fig. 7 respectively. fig. 3. productivity index versus lateral length for different (kr) ratios, well no. (32) fig. 4. following well pressure drop versus lateral length for two different (kr) , well no. (32) with s=0 fig. 5. comparison for the productivity lateral section length for two wells fig. 6. production rate versus lateral section lenght for different (kr) ratio well no. (32) with s=0 fig. 7. well production rate versus lateral section length for different (kr) ratios, well (eb-10) with s=-4 for the well eb-32, the results show that the production capacity could be increased between (30%-100%) than the production capacity for that of vertical well for each (100 ft) lateral section length increment depends on the vertical to horizontal permeability ratios (kr), notice that minimum section length in which the production capacity will be equal to that of vertical well should be not less than (260 ft). while, the well shows high sensitive to the acids stimulation activity (-s) and could be response to increase the production capacity between (68%-80%) for each degree of stimulation (s= -1). meanwhile, the well shows poor response to stimulation by fracturing stimulation. a. a.alhaleem a.alrazzaq / iraqi journal of chemical and petroleum engineering 20,3 (2019) 75 79 67 6conclusion and recommendations investigating figures 1 and 6; it could be noticed that increasing well lateral section in low vertical to horizontal permeability ratios (kr) has little effects in increasing well production and then could be recommend to use small lateral section lengths (1000 – 2000 ft) and by adding the effects of acid stimulation activity to those wells to extra increase the production rate as shown in figure 7. moreover, it could be seen from figure 4 the wells will need for high flowing pressure drop in low vertical to horizontal permeability ratios (kr) when using lateral sections less than (1500 ft), while the required flowing pressure drop could be much lower when using lateral section lengths of (2000 – 3000 ft). however, wells of lateral section greater than (2000ft) may not cause a considerable minimizing the flowing pressure drop, that conclusion led us to recommend converting well eb-32 to a re-entry horizontal well with lateral section of (15002000 ft) keeping in mind acid stimulation process to increase the production rate. it can be concluded that no measurements available for the ratio of anisotropy (kv/kh); in east baghdad oil field therefore, the wells productivity has been estimated using wide range of anisotropy ratios that will help the field operator to determine exactly wells productivity. moreover, it helps to recommend the effectiveness of applying hydraulic fracturing in improving horizontal well productivity nomenclatures api: american petroleum institute eb: east baghdad oil field kv: vertical permeability kh: horizantal permeability kr: relative permability pta: pressure transient analysis s: skin factor sw: water saturation references [1] hasan ali n. ,ayad a.alhaleem,"torgue and drag forces problems in highly deviated oil well", iraqi journal of chemical and petroleum engineering,vol.19,no.3,p.p.19-31,septemper 2018. [2] mohammed s.al.j,a.a.al-dabaj and hassan a.hadi,"design of horizontal well program for ajeel field", iraqi journal of chemical and petroleum engineering,vol.15,no.1,p.p.59-63,march 2014. [3] ghanim m.f.,maha r.abdulamir," formulation of new equation to estimate productivity index of horizontal wells", iraqi journal of chemical and petroleum engineering,vol.15,no.2,p.p.61-73,june 2014. [4] jalal abdulwahid al-sudani," analytical model for detection the tilt in originally oil water contacts", iraqi journal of chemical and petroleum engineering,vol.15,no.3,p.p.51-60,september 2014 [5] mid field oil company "final well reports", iraq, 2005. [6] mid field oil company "final well reports", iraq, 1999. [7] m.s. al-blehed et.al. “horizontal wells find varied applications in saudi fields”, oil and gas journal,may-2000. [8] abdullah m. al-qahtani, and habib menouar" new correlations for optimizing horizontal wells completions",spe37768-1997. [9] michael j. economides,” completion technology for unconsolidated formation”, rev.2-1995. [10] joshi, s. d., "horizontal well technology", penn. well publishing company, tulsa, ok, usa, 1991. [11] fekete associates “advance software technology”,version-2009. appendix a f.a.s.t well test tm is used to perform pressure transient analysis (pta) to interpret reservoir flow characteristics and predict future reservoir production. the information contained within this help document describes the appropriate pta theory and terminology used in the software horizontal model the horizontal model simulates the pressure response in a horizontal well within a rectangular shaped reservoir with anisotropic heterogeneities (differences in permeability in the x, y, and z directions) or dual porosity characteristics. the anisotropy is handled using a conformal mapping procedure which adjusts the boundary sizes accordingly to mimic the effect of increased or decreased permeability in each direction. the horizontal well is oriented in the x-direction and may be at any location within the reservoir and support infinite no flow, and constant pressure boundaries. note that the effective wellbore length (le) defines the wellbore area open to fluid flow. thus, classical configuration like a well near a sealing fault or a constant pressure boundary near intersecting faults can be easily modeled . no flow boundaries are modeled using the method of images. the result is superposed in time based on the rate history provided. https://doi.org/10.31699/ijcpe.2018.3.3 https://doi.org/10.31699/ijcpe.2018.3.3 https://doi.org/10.31699/ijcpe.2018.3.3 https://doi.org/10.31699/ijcpe.2018.3.3 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/269 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/269 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/269 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/269 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/278 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/278 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/278 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/278 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/278 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/288 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/288 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/288 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/288 https://www.ogj.com/home/article/17215008/horizontal-wells-find-varied-applications-in-saudi-fields https://www.ogj.com/home/article/17215008/horizontal-wells-find-varied-applications-in-saudi-fields https://www.ogj.com/home/article/17215008/horizontal-wells-find-varied-applications-in-saudi-fields https://doi.org/10.2118/37768-ms https://doi.org/10.2118/37768-ms https://doi.org/10.2118/37768-ms http://www.uomisan.edu.iq/eng/ar/admin/pdf/96959566883.pdf http://www.uomisan.edu.iq/eng/ar/admin/pdf/96959566883.pdf https://www.osti.gov/biblio/5798453 https://www.osti.gov/biblio/5798453 https://www.osti.gov/biblio/5798453 a. a.alhaleem a.alrazzaq / iraqi journal of chemical and petroleum engineering 20,3 (2019) 75 79 68 تطوير حقل شرق بغداد النفطي بواسطة مجاميع من اآلبار االفقية الرزاق عبد الحليم عبد أياد بغداد جامعة-اليندسة كمية الخالصة استخالص زيادة.اآلبارالعمودية عمى االفقية اآلبار حفر تفضيل الى تؤدي التي االسباب من العديد توجد من الطريقة ىذه الختيار العوامل اىم من يعتبر النفاذيو القميمة المكامن او السمك القميمة التراكيب من النفط .الحفر نفطي برميل مميار 11 يتجاوز مؤكد باحتياطي العمالقو النفطية الحقول من النفطي بغداد شرقي حقل يعتبر االفقية اآلبار استخدام دراسة فان لذلك. الموجودة اآلبار من العديد في القميل االنتاج مشكمة حاليا معو يترافق يعتبر قد افقيا منيا المقاطع بعض حفر باعادة المحفورة اآلبار بعض تغيير وخصوصا بغداد شرقي حقل في متعدد الحفر استخدام او افقية آبار بحفر يتبع ان يمكن والذي الحقل ىذا في التطويرية الحمول افضل من واحدا لتحسين افقية الى الحالية العمودية اآلبار لتغيير( التحويرات بعض مع)متطور برنامج استخدام تم. االذرع .االنتاج في( االفقيو النفاذيو/ العموديو النفاذيو)لمنسبو حقميو قياسات التوجد انو استنتاج يمكن انو الدراسو نتائج تبين النفاذيو تباين نسب من واسع مدى باستخدام تخمينيا تم قد االبار انتاجية فان وعميو النفطي بغداد شرقي حقل في تساعد فانيا ذلك الى اضافة. دقيقة بصورة االبار انتاجية معرفة او حساب في الحقل مشغمي ستساعد والتي .النفطي بغداد شرقي حقل في االفقيو االبار انتاجية لتطوير اليايدروليكي التشقيق تقنية استخدام بكفاءة التوصية ( 2000-1000) بطول افقي مقطع امثل مع جديد افقي كبئر eb-32 البئر استخدام يمكن انو النتائج اظيرت انتاج معدل مع eb-10 البئر مع النتيجة نفس عمى الحصول يمكن و انتاج معدل افضل سيعطي والذي قدم eb-32 بالبئر مقارنة اعمى الكممات الدالة: االبار االفقية, االنتاجية, النفاذية العمودية available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.22 no.3 (september 2021) 11 – 17 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: ghazwan s. ahmed , email: ghazwan.s.ahmed@tu.edu.iq, name: jasim i. humadi, email: jasim_alhashimi_ppe@tu.edu.iq, name: ahmad a. aabid, email: ahmadchemical1991@uomosul.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. mathematical model, simulation and scale up of batch reactor used in oxidative desulfurization of kerosene ghazwan s. ahmed a , jasim i. humadi b and ahmad a. aabid c a chemical engineering department, college of engineering, tikrit university, iraq b petroleum and gas refining engineering department, college of petroleum & minerals engineering, tikrit university, iraq c petroleum reservoir engineering department, college of petroleum &mining, mosul university, iraq abstract in this paper, a mathematical model for the oxidative desulfurization of kerosene had been developed. the mathematical model and simulation process is a very important process due to it provides a better understanding of a real process. the mathematical model in this study was based on experimental results which were taken from literature to calculate the optimal kinetic parameters where simulation and optimization were conducted using gproms software. the optimal kinetic parameters were activation energy 18.63958 kj/mol, pre-exponential factor 2201.34 (wt) -0.76636 . min -1 and the reaction order 1.76636. these optimal kinetic parameters were used to find the optimal reaction conditions which used to obtain a high conversion (≥ 99%). these optimal reaction conditions were reaction temperature 379.4 o k and reaction time 160 min. a scale up to batch reactor was conducted using these optimal kinetic parameters and optimal reaction conditions and the results showed the best reactor size that can be used at a diameter of 1.2 m. keywords: mathematical model, optimal kinetic parameters, optimal reaction condition, scale up, batch reactor received on 27/05/2021, accepted on 16/07/2021, published on 30/09/2021 https://doi.org/10.31699/ijcpe.2021.3.2 1introduction petroleum fractions contain different types of sulfur compounds (thiols, sulfides, and thiophenes) which is harmful compound to industry and environment [1]. these compounds are undesirable in petroleum fractions because they poison the catalyst in refinery and cause corrosion problems of internal combustion engines, also can emit so2 in the combustion process [1,2]. due to these disadvantages, many techniques have been developed for sulfur removal [3]. one of these techniques is the oxidative desulfurization (ods) process which receives more attention because it operates under low operation conditions and doesn’t consume hydrogen compared with hydrodesulfurization (hds) [3]. thus, the ods process was studied by a lot of researchers using different catalysts and oxidants under different operating conditions and for different petroleum fractions [1-6]. despite this experimental study, the simulation process and modeling become necessary because they provide a better understanding of the process [7]. the mathematical model of chemical processes involves several simulations and optimization that have many advantages such as estimation of the optimal operations without making any change on the real process. the process model is very efficient and profitable due to huge operations, control, safety, and design systems [8]. finding a model which describes the experimental process under different process conditions consider a hard task challenge due to the experimental process contain several types of structure [16]. the mathematical model for a batch reactor can be complex due to the effect of many factors inside the reactor including mixing efficiency, size and shape of catalyst particles, kinetics on the catalyst surface, and pore diffusion within the framework effective or apparent reaction rate constant [17,18]. this study aims to find optimal kinetic parameters by applying a mathematical model and compared the results from the model with experimental results taken from the literature [9]. these kinetic parameters were used to find optimum reaction conditions which can give high conversion (>99%). also, this study includes the scale-up study of batch reactor based on optimal kinetic parameters and optimum reaction conditions to find the appropriate volume of the reactor. 2methods and methodology 2.1. process description the simulation results were made on experimental results taken from literature. the experimental section is consisting of a batch reactor for oxidative desulfurization of mercaptans from kerosene using merox on activated carbon catalyst in alkaline solution by air as oxidant. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:ghazwan.s.ahmed@tu.edu.iq mailto:jasim_alhashimi_ppe@tu.edu.iq mailto:ahmadchemical1991@uomosul.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2021.3.2 g. s. ahmed et al. / iraqi journal of chemical and petroleum engineering 22,3 (2021) 11 17 12 in order to easy for matching between experimental and simulation results some assumptions are used:  the gaseous reactant exists in large excess and the liquid is saturated with gas at all times.  isothermal and constant pressure in the reactor.  steady state experimental unit.  the reactant used in the model section consists of butanethiol and behaves as butanethiol in properties because it considers the most sulfur compound present in kerosene. and the reaction can be stated below where thoils oxidize on the catalyst using air as an oxidant to produce disulfide which can remove easily by the adsorption process because it has high polarity. 𝑅𝑆𝐻 + 𝑂2 → 𝑅𝑆𝑆𝑅 2.2. mathematical model the mathematical model is a set of algebraic and differential equations which can be solved by computational technique. the mathematical model of chemical processes involves several simulations and optimization that have many advantages such as estimation of the optimal operations without making any change on the real process. it can be developed by the formulation of the equations of mass and energy balance. a basic mathematical model will include a chemical reaction rate and combination mass and heat transfer equations with the kinetic equation [10]. the mathematical model can be started by making material balance about batch reactor concerning mercaptan concentration and this lead to [12]: t=∫ −𝑑𝐶𝑅𝑆𝐻 (−𝑟𝑅𝑆𝐻) crsh crsho (1) the reaction rate of chemical reaction could be taken into account by assuming n th order kinetics. (-rrsh) = kappcrsh n (2) the apparent kinetic constant was related to intrinsic kinetic constant by internal diffusion which was represented by the catalyst effectiveness factor (ƞo) as follows[11,12]: kapp = ƞo kin (3) by substitution of eq. (2) and (3) in eq. (1) and integration to this equation we can get the final expression which is: 𝐶𝑅𝑆𝐻 = [𝐶𝑅𝑆𝐻𝑂 (1−𝑛) + (𝑛 − 1). 𝑡. 𝑘𝑖𝑛 . ƞ𝑜 ] ( 1 (1−𝑛) ) (4) the reaction rate constant (kin) can be calculated for ods reaction by using the arrhenius equation as follows: kin =ko 𝑒 ( −𝐸 𝑅𝑇 ) (5) eq. (4) contain effectiveness factor which can be calculated from the following equation that can be used for sphere particle [11, 12]: ƞo= 3(ф coth(ф)−1) ф2 (6) effectiveness factor is a function of thiele modulus which is calculated from the following equation [14]: ф= 𝑉𝑝 𝑆𝑝 √ (𝑛+1) 2 𝐾𝑖𝑛𝐶𝑅𝑆𝐻 (𝑛−1) 𝐷𝑒 (7) molecular diffusivity which is present in eq. (7) can be estimated from the equation [9]: de= 7.8*10 -8 𝜓𝐵 𝑀𝐵 (ʋ𝑅𝑆𝐻) 0.6 𝑇 𝜇 (8) where:𝜓𝐵 non-aggregation coefficient. (this is equal to 1 for kerosene) the molar volume of solute is calculated from the following equation [11, 12]: ʋ𝑅𝑆𝐻 = 0.285(ʋ𝑐𝑅𝑆𝐻 ) 1.048 (9) the equations (1) to (9) were coded and simultaneously solved by gproms software. the mathematical model was used to estimate the optimal kinetic parameters by minimizing the absolute error between experimental and predicted data. in order to calculate the optimal kinetic parameters using the gproms software we must reduce the value of sum of square error (sse) below [13]: sse = ∑ (𝐶𝑅𝑆𝐻𝑒𝑥𝑝 − 𝐶𝑅𝑆𝐻𝑝𝑟𝑒𝑑 ) 2𝑖 1 (10) where ( i) represent the number of runs. the mathematical model was containing several constant parameters which showed in table 1. table 1. values of constant parameters used in ods model value unit symbol parameter co=0.0193 wt% co initial concentration t1=303, t2=313, t3=323 o k t1, t2, t3 temperature tim1=5, tim2= 30, tim3=60 tim4=90, tim5=120 min tim1, tim2, tim3, tim4, tim5 batch time 8.314 j/mol. o k r gas constant 96.38 g/cm 3 ʋ𝑅𝑆𝐻 molar volume 0.4 mm rp particle radius g. s. ahmed et al. / iraqi journal of chemical and petroleum engineering 22,3 (2021) 11 17 13 2.3. scale up of batch reactor the model of batch reactor was developed by making material balance about reactor and energy balance for reactor and jacket which can be used to control the temperature of the reactor. material and energy balance will lead to the following set of ordinary differential equations [15]: material balance: 𝑑𝑐 𝑑𝑡 = −𝑘𝑖𝑛 𝐶 𝑛 (11) energy balance: reactor: 𝑑𝑇 𝑑𝑡 = 𝑈𝐴 𝜌𝑟 𝐶𝑝𝑟 𝑉 (𝑇𝑗 − 𝑇) + ∆𝐻 𝑟𝑅𝑆𝐻 𝑉 𝜌𝑟 𝐶𝑝𝑟 𝑉 + 𝜇 𝑁2 𝑉 𝜌𝑟 𝐶𝑝𝑟 𝑉 (12) jacket: 𝑑𝑇𝑗 𝑑𝑡 = − 𝑈𝐴 𝜌𝑗 𝐶𝑝𝑗 𝑉𝑗 (𝑇𝑗 − 𝑇) + 𝐹 𝑉𝑗 (𝑇𝑗 − 𝑇𝑛 ) (13) the following equations were acquired to solve these differential equations: a=𝜋 𝐷 𝐿 (14) v= 𝜋 4 𝐷2𝐿 (15) 𝑉𝑗 = 𝜋 4 (𝐷𝑗 2 − 𝐷2)𝐿 (16) l=1.5d (17) and 𝐷𝑗 = 1.3𝐷 (18) the viscosity of kerosene is used as a function of temperature which is estimated from the experimental result in literature: 𝜇 = 0.016𝑇 − 3.548 (19) the model of scale up of batch reactor contains several numerical values which showed in table 2. table 2. constants used in scale up model value unit symbol parameter 4.2 kj/kg k cpj jacket solution heat capacity 1000 kg/𝑚3 𝜌𝑗 jacket solution density 2.01 kj/kg k cpr reactor solution heat capacity 815.5 kg/𝑚3 𝜌𝑟 reactor solution density 2000 rpm n impeller speed 225.406 kj/mol h heat of reaction 24 kw/m 2 o k u overall heat transfer coefficient 420 o k tn input steam temperature 3results and discussion 3.1. kinetic parameters estimation the optimal kinetic parameters which were calculated from the model by minimizing the function (sse) were shown in table 3. table 3. optimal kinetic parameters predicted from the model unit value parameter 1.76636 𝑛 kj/mol 18.63958 e (wt) -0.76636 . min -1 2201.34 ko 3.2 simulation and experimental results the experimental and simulation results are present in table 4. the simulation results were obtained from the model by gproms software. while the comparison between experimental and simulation results was shown in fig. 1 to fig. 3. table 4. experimental and simulation results experimental conversion (%) experimental concentration (ppm) simulation conversion (%) concentration by simulation (ppm) batch time (min) temperatur e (k) 21.24 152 25.30 144.17 5 303 66.06 65.5 69.79 58.29 30 303 83.67 31.5 83.65 31.55 60 303 88.34 22.5 89.21 20.82 90 303 92.48 14.5 92.12 15.20 120 303 26.16 142.5 30.20 134.70 5 313 73.83 50.5 75.11 48.02 30 313 88.34 22.5 87.11 24.87 60 313 92.48 14.5 91.66 16.09 90 313 93.52 12.5 93.98 11.61 120 313 30.82 133.5 35.30 124.87 5 323 80.05 38.5 79.56 39.44 30 323 90.67 18 89.80 19.67 60 323 92.74 14 93.50 12.53 90 323 94.81 10 95.35 8.96 120 323 fig. 1. comparison between experimental and simulation results at t=303 o k g. s. ahmed et al. / iraqi journal of chemical and petroleum engineering 22,3 (2021) 11 17 14 fig. 2. comparison between experimental and simulation results at t=313 o k fig. 3. comparison between experimental and simulation results at t=323 o k fig. 1 to fig. 3 above shows the effect of time on the conversion at different temperatures in addition to comparing experimental and simulation results. from these figures, we can observe that the conversion was increased by increasing the temperature and time, increasing temperature will increase the number of attractive molecules, and this leads to an increase in the conversion. also, increasing the temperature will increase the rate constant according to the arrhenius equation, and this lead to an increase in the reaction rate while increasing the time will increase the contact time between the reacting materials and the active sites of the catalyst [12, 13]. also, these figures showed the comparison between experimental and simulation results and we can see good matching between the simulation and experimental results because a few assumptions are used in this work and this assumption is used to ease the solving of the model where reducing the number of assumptions will increase the matching between experimental and simulation results. 3.3. optimal reaction conditions after getting the optimal kinetic parameters, these optimal parameters can be used in the model to find the optimal reaction conditions which can be used to get a high conversion (≥ 99%) and these conditions are shown in table 5. table 5. optimal reaction conditions for high conversion parameter value unit temperature 379.4 k time 160 min conversion 99.135 % 3.4 scale up of batch reactor the scale up of the batch reactor is studied under different reactor sizes to observe the effect of size on the concentration and temperature in the model. the scale up model is used in gproms software to study the output temperature and concentration under different reactor sizes and these values were presented in tables 6 and 7 below. from these tables, the best value for diameter was at d=1.2 m due to that when d=1.2 m, the value of concentration reach to minimum value and the temperature profile were more stable from the other value to diameter, in addition, consider the nearest value to the optimal temperature of high conversion. so that, from this study for scale up to batch reactor used here the diameter will be 1.2 m which can be depending it other dimensions of the reactor. table 6. effect of the reactor size on concentration profile (concentration in ppm). time(min) d=1(m) d=1.2(m) d=1.4(m) d=1.6(m) d=1.8(m) d=2(m) 0.0 193 193 193 193 193 193 10.0 78.94 83.33 86.88 89.83 92.27 94.35 20.0 34.42 37.29 39.96 42.40 44.64 46.68 30.0 19.18 20.68 22.15 23.60 25.00 26.35 40.0 12.56 13.39 14.23 15.08 15.92 16.77 50.0 9.09 9.57 10.08 10.61 11.13 11.68 60.0 7.01 7.31 7.63 7.98 8.32 8.69 70.0 5.65 5.84 6.06 6.29 6.53 6.78 80.0 4.70 4.83 4.98 5.14 5.31 5.50 90.0 4.00 4.09 4.19 4.31 4.44 4.58 100.0 3.47 3.53 3.60 3.70 3.79 3.89 110.0 3.05 3.09 3.15 3.22 3.29 3.37 120.0 2.72 2.74 2.79 2.84 2.90 2.96 130.0 2.44 2.46 2.49 2.53 2.58 2.63 140.0 2.22 2.22 2.25 2.28 2.32 2.36 150.0 2.03 2.02 2.04 2.07 2.10 2.14 160.0 1.86 1.85 1.87 1.89 1.92 1.95 g. s. ahmed et al. / iraqi journal of chemical and petroleum engineering 22,3 (2021) 11 17 15 table 7. effect of the reactor size on temperature profile (temperature in k) time(min) d=1(m) d=1.2(m) d=1.4(m) d=1.6(m) d=1.8(m) d=2(m) 0.0 300.0 300.0 300.0 300.0 300.0 300.0 10.0 354.04 348.53 343.94 340.10 336.84 334.05 20.0 372.58 368.49 364.48 360.72 357.25 354.07 30.0 378.79 376.62 374.04 371.30 368.53 365.82 40.0 380.73 379.87 378.45 376.71 374.77 372.71 50.0 381.19 381.11 380.46 379.45 378.20 376.75 60.0 381.14 381.51 381.34 380.84 380.07 379.11 70.0 380.90 381.56 381.70 381.51 381.09 380.48 80.0 380.60 381.47 381.80 381.82 381.63 381.27 90.0 380.27 381.33 381.78 381.94 381.90 381.71 100.0 379.94 381.15 381.71 381.96 382.03 381.96 110.0 379.60 380.97 381.62 381.94 382.07 382.09 120.0 379.26 380.78 381.51 381.88 382.08 382.15 130.0 378.91 380.59 381.39 381.82 382.05 382.17 140.0 378.56 380.39 381.28 381.75 382.01 382.16 150.0 378.20 380.20 381.16 381.67 381.97 382.14 160.0 377.85 380.00 381.04 381.60 381.92 382.11 4conclusions in this study, a mathematical model was developed to simulate experimental results. the mathematical model is used to find the optimal kinetic parameters based on experimental results and then used them to find the optimal reaction conditions which can give high conversion. the optimal kinetic parameters and the optimal reaction conditions which was presented in this study is used to the scale up of batch reactor . the results showed that the best size to reactor which achieve the high conversion and temperature nearest to optimal value was at reactor diameter of 1.2 m. nomenclature crsh : mrcaptan concentration, wt%. crsho : initial concentration of mercaptan, wt%. t: temperature, o k. t: time, min kapp : apparent rate constant, (wt) -0.76636 . min -1 . kin : intrinsic rate constant, (wt) -0.76636 . min -1 . ko: pre-exponential factor, (wt) -0.76636 . min -1 . e: activation energy, kj/mol. r: gas constant, j/mol o k. n: order of reaction. ƞo : effectiveness factor. ф: thiele modulus. (-rrsh): reaction rate, wt%/sec. de: effective diffusivity, cm 2 /sec. 𝜓𝐵 : non-aggregation coefficient. 𝑀𝐵: molecular weight of solvent, g/gmol. ʋ𝑅𝑆𝐻 : molar volume of mercaptan, m 3 /mol. ʋ𝑐𝑅𝑆𝐻 : critical molar volume of mercaptan, m 3 /mol. 𝜇: viscosity, pa.s. vp : particle volume, m 3 . sp: external surface area of particle, m 2 . u: overall heat transfer coefficient, kw/m 2 o k. 𝜌𝑗 : density of solution in jacket, kg/m 3 . 𝐶𝑝𝑗 : heat capacity of solution in jacket, kj/kg o k. 𝑉𝑗 : jacket volume, m 3 . 𝜌𝑟 : density of solution in reactor, kg/m 3 . 𝐶𝑝𝑟 : heat capacity of solution in reactor, kj/kg o k. 𝑉: reactor volume , m 3 . d: reactor diameter, m. l: reactor height, m. dj : diameter of jacket, m. f: steam flow rate, kg/s. tn: temperature of input steam, o k. tj: jacket temperature, o k. n: impeller speed, rpm. ∆𝐻: heat of reaction, kj/mol. sse: sum of square error references [1] j.m. campos-martin, m.c. capel-sanchez, p. perezpresas and j.l.g. fierro, “oxidative processes of desulfurization of liquid fuels”. journal of chemical technology & biotechnology, vol. 85(7),pp. 879-890, march. 2010. [2] n.m. meman, b. zarenezhad, a. rashidi, h. zeinab and e. esmaeili, “application of palladium supported on functionalized mwnts for oxidative desulfurization of naphtha”. journal of industrial and engineering chemistry, vol. 22, pp.179-184, feb. 2015. [3] k. yazu, a. matsumura and s. sato, “oxidative desulfurization of naphtha with hydrogen peroxide in presence of acid catalyst in naphtha/acetic acid biphasic system”. journal of the japan petroleum institute , vol. 53(4), pp. 251-255, 2010. [4] c. song, “an overview of new approaches to deep desulfurization for ultra-clean gasoline, diesel fuel and jet fuel”. catalysis today, vol. 86(1-4), pp. 211263, nov. 2003. [5] z. wu and b. ondruschka, “ultrasound-assisted oxidative desulfurization of liquid fuels and its industrial application”. ultrasonics sonochemistry vol. 17(6), pp. 1027-1032, aug. 2010. [6] w. liang, s. zhang, h. li and g. zhang,“oxidative desulfurization of simulated gasoline catalyzed by acetic acid-based ionic liquids at room temperature”. fuel processing technology, vol. 109, pp. 27-31, may. 2013. [7] a.t. nawaf, “experimental and modeling study for desulfurization of light gas oil by catalytic wet air oxidation process”. msc. thesis, tikrit university, iraq, 2015. https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.2371 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.2371 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.2371 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.2371 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.2371 https://www.sciencedirect.com/science/article/abs/pii/s1226086x14003529 https://www.sciencedirect.com/science/article/abs/pii/s1226086x14003529 https://www.sciencedirect.com/science/article/abs/pii/s1226086x14003529 https://www.sciencedirect.com/science/article/abs/pii/s1226086x14003529 https://www.sciencedirect.com/science/article/abs/pii/s1226086x14003529 https://www.sciencedirect.com/science/article/abs/pii/s1226086x14003529 https://www.jstage.jst.go.jp/article/jpi/53/4/53_4_251/_article/-char/ja/ https://www.jstage.jst.go.jp/article/jpi/53/4/53_4_251/_article/-char/ja/ https://www.jstage.jst.go.jp/article/jpi/53/4/53_4_251/_article/-char/ja/ https://www.jstage.jst.go.jp/article/jpi/53/4/53_4_251/_article/-char/ja/ https://www.jstage.jst.go.jp/article/jpi/53/4/53_4_251/_article/-char/ja/ https://www.sciencedirect.com/science/article/abs/pii/s0920586103004127 https://www.sciencedirect.com/science/article/abs/pii/s0920586103004127 https://www.sciencedirect.com/science/article/abs/pii/s0920586103004127 https://www.sciencedirect.com/science/article/abs/pii/s0920586103004127 https://www.sciencedirect.com/science/article/pii/s135041770900193x https://www.sciencedirect.com/science/article/pii/s135041770900193x https://www.sciencedirect.com/science/article/pii/s135041770900193x https://www.sciencedirect.com/science/article/pii/s135041770900193x https://www.sciencedirect.com/science/article/pii/s0378382012003608 https://www.sciencedirect.com/science/article/pii/s0378382012003608 https://www.sciencedirect.com/science/article/pii/s0378382012003608 https://www.sciencedirect.com/science/article/pii/s0378382012003608 https://www.sciencedirect.com/science/article/pii/s0378382012003608 g. s. ahmed et al. / iraqi journal of chemical and petroleum engineering 22,3 (2021) 11 17 16 [8] h. khalfalla, “modeling and optimization of oxidative desulfurization process for model sulfur compounds and heavy gas oil”. philosophy of doctor thesis, university of bradford, uk, 2009. [9] a. farshi and z. rabiei, “kinetic study for oxidation of existing mercaptans in kerosene using impregnated activated carbon with merox catalyst in alkaline solution”. petroleum & coal, vol. 47(1), pp. 49-56, jan. 2005. [10] m. al-dahhan, f. larachi, m. dudukovic and a. laurent, “high pressure trickle bed reactors. a review”. industrial & engineering chemistry research, vol. 36(8), pp. 3292-3314, aug.1997. [11] g. marroquín, j. ancheyta and c. esteban , “a batch reactor study to determine effectiveness factors of commercial hds catalyst”. catalysis today, vol. 104(1), pp. 70-75, jun. 2005. [12] g.s. ahmed, a.t. jarullah, b.a. al-tabbakh and i.m. mujtaba, “design of an environmentally friendly reactor for naphtha oxidative desulfurization by air employing a new synthetic nano-catalyst based on experiments and modeling”. journal of cleaner production ,vol. 257, pp. 120436, jun. 2020. [13] a.t. jarullah, g.s. ahmed, b.a. al-tabbakh and i.m. mujtaba, “enhancement of light naphtha quality and environment using new synthetic nanocatalyst for oxidative desulfurization: experiments and process modeling”. computers and chemical engineering, vol. 140, pp. 106869, sep. 2020. [14] r.j. wijngaarden, a. kronberg and k.r. westertrep, “calculation of effectiveness factor”, wiley-vch: veriag gmbh, 1998. [15] r.o. vargas and f. lópez-serrano, “modeling, simulation and scale-up of a batch reactor”. in: klapp j., medina a. (eds) experimental and computational fluid mechanics. environmental science and engineering. springer, cham. jan. 2014. [16] a.t. jarullah, i.m. mujtaba and a.s. wood, “kinetic model development and simulation of simultaneous hydrodenitrogenation and hydrodemetallization of crude oil in trickle bed reactor”. fuel, vol. 90, pp. 2165-2181, jun. 2011. [17] j.a. paraskos, j.a. frayer and y.t. shah, “effect of holdup incomplete catalyst wetting and back mixing during hydro-processing in trickle bed reactors”. industrial & engineering chemistry process design and development, vol. 14(3), pp. 315322, jul.1975. [18] h.p. hofman, “multiphase catalytic packed-bed reactors”. catalysis reviews science and engineering, vol. 17(1), pp. 71-117, 1978. https://www.researchgate.net/profile/amir-farshi/publication/26500376_kinetic_study_for_oxidation_of_existing_mercaptans_in_kerosene_using_impregnated_activated_carbon_with_merox_catalyst_in_alkaline_solution/links/09e4150ed21787a63d000000/kinetic-study-for-oxidation-of-existing-mercaptans-in-kerosene-using-impregnated-activated-carbon-with-merox-catalyst-in-alkaline-solution.pdf https://www.researchgate.net/profile/amir-farshi/publication/26500376_kinetic_study_for_oxidation_of_existing_mercaptans_in_kerosene_using_impregnated_activated_carbon_with_merox_catalyst_in_alkaline_solution/links/09e4150ed21787a63d000000/kinetic-study-for-oxidation-of-existing-mercaptans-in-kerosene-using-impregnated-activated-carbon-with-merox-catalyst-in-alkaline-solution.pdf https://www.researchgate.net/profile/amir-farshi/publication/26500376_kinetic_study_for_oxidation_of_existing_mercaptans_in_kerosene_using_impregnated_activated_carbon_with_merox_catalyst_in_alkaline_solution/links/09e4150ed21787a63d000000/kinetic-study-for-oxidation-of-existing-mercaptans-in-kerosene-using-impregnated-activated-carbon-with-merox-catalyst-in-alkaline-solution.pdf https://www.researchgate.net/profile/amir-farshi/publication/26500376_kinetic_study_for_oxidation_of_existing_mercaptans_in_kerosene_using_impregnated_activated_carbon_with_merox_catalyst_in_alkaline_solution/links/09e4150ed21787a63d000000/kinetic-study-for-oxidation-of-existing-mercaptans-in-kerosene-using-impregnated-activated-carbon-with-merox-catalyst-in-alkaline-solution.pdf https://www.researchgate.net/profile/amir-farshi/publication/26500376_kinetic_study_for_oxidation_of_existing_mercaptans_in_kerosene_using_impregnated_activated_carbon_with_merox_catalyst_in_alkaline_solution/links/09e4150ed21787a63d000000/kinetic-study-for-oxidation-of-existing-mercaptans-in-kerosene-using-impregnated-activated-carbon-with-merox-catalyst-in-alkaline-solution.pdf https://pubs.acs.org/doi/abs/10.1021/ie9700829 https://pubs.acs.org/doi/abs/10.1021/ie9700829 https://pubs.acs.org/doi/abs/10.1021/ie9700829 https://pubs.acs.org/doi/abs/10.1021/ie9700829 https://www.sciencedirect.com/science/article/abs/pii/s0920586105000908 https://www.sciencedirect.com/science/article/abs/pii/s0920586105000908 https://www.sciencedirect.com/science/article/abs/pii/s0920586105000908 https://www.sciencedirect.com/science/article/abs/pii/s0920586105000908 https://www.sciencedirect.com/science/article/abs/pii/s0959652620304832 https://www.sciencedirect.com/science/article/abs/pii/s0959652620304832 https://www.sciencedirect.com/science/article/abs/pii/s0959652620304832 https://www.sciencedirect.com/science/article/abs/pii/s0959652620304832 https://www.sciencedirect.com/science/article/abs/pii/s0959652620304832 https://www.sciencedirect.com/science/article/abs/pii/s0959652620304832 https://www.sciencedirect.com/science/article/abs/pii/s0959652620304832 https://www.sciencedirect.com/science/article/abs/pii/s0098135420300508 https://www.sciencedirect.com/science/article/abs/pii/s0098135420300508 https://www.sciencedirect.com/science/article/abs/pii/s0098135420300508 https://www.sciencedirect.com/science/article/abs/pii/s0098135420300508 https://www.sciencedirect.com/science/article/abs/pii/s0098135420300508 https://www.sciencedirect.com/science/article/abs/pii/s0098135420300508 https://link.springer.com/chapter/10.1007/978-3-319-00116-6_18 https://link.springer.com/chapter/10.1007/978-3-319-00116-6_18 https://link.springer.com/chapter/10.1007/978-3-319-00116-6_18 https://link.springer.com/chapter/10.1007/978-3-319-00116-6_18 https://link.springer.com/chapter/10.1007/978-3-319-00116-6_18 https://link.springer.com/chapter/10.1007/978-3-319-00116-6_18 https://www.sciencedirect.com/science/article/abs/pii/s0016236111000275 https://www.sciencedirect.com/science/article/abs/pii/s0016236111000275 https://www.sciencedirect.com/science/article/abs/pii/s0016236111000275 https://www.sciencedirect.com/science/article/abs/pii/s0016236111000275 https://www.sciencedirect.com/science/article/abs/pii/s0016236111000275 https://pubs.acs.org/doi/pdf/10.1021/i260055a021 https://pubs.acs.org/doi/pdf/10.1021/i260055a021 https://pubs.acs.org/doi/pdf/10.1021/i260055a021 https://pubs.acs.org/doi/pdf/10.1021/i260055a021 https://pubs.acs.org/doi/pdf/10.1021/i260055a021 https://pubs.acs.org/doi/pdf/10.1021/i260055a021 https://www.tandfonline.com/doi/abs/10.1080/03602457808080879 https://www.tandfonline.com/doi/abs/10.1080/03602457808080879 https://www.tandfonline.com/doi/abs/10.1080/03602457808080879 g. s. ahmed et al. / iraqi journal of chemical and petroleum engineering 22,3 (2021) 11 17 17 نموذج رياضي و محاكاة وتوسيع نطاق المفاعل الدفعي المستخدم في عملية ازالة باالكسدة من الكيروسينالكبريت 3 احمد عبد السالم عابد و 2 , جاسم ابراهيم حمادي1غزوان صالح احمد قسم الهندسة الكيمياوية, كلية الهندسة, جامعة تكريت, العراق 1 قسم هندسة عمليات تكرير النفط والغاز, كلية هندسة النفط والمعادن, جامعة تكريت, العراق 2 قسم هندسة المكامن النفطية, كلية هندسة النفط والتعدين, جامعة الموصل, العراق 3 الخالصة في هذا البحث ، تم تطوير نموذج رياضي إلزالة الكبريت باالكسدة من الكيروسين. يعد النموذج الرياضي الحقيقية. اعتمد النموذج الرياضي في وعملية المحاكاة عملية مهمة للغاية نظًرا ألنه يوفر فهًما أفضل للعملية هذه الدراسة على نتائج تجريبية مأخوذة من األدبيات من أجل حساب المعامالت المثلى لحركية التفاعل. كانت 2201.34كيلوجول / مول ، وعامل ما قبل األسي 18.63958المعامالت الحركية المثلى هي طاقة التنشيط . تم استخدام هذه المعامالت الحركية المثلى إليجاد ظروف 1.76636بة التفاعل ومرت 1-. دقيقة0.76636-( )وزن هي المثلى التفاعل ظروف كانت(. ٪99 ≤التفاعل المثلى التي تم استخدامها للحصول على تحويل عالي ) تخدام توسيع نطاق للمفاعل الدفعي باس إجراء تم. دقيقة 160 التفاعل وزمن كلفن 379.4 التفاعل حرارة درجة هذه المعامالت الحركية المثلى وظروف التفاعل المثلى وأظهرت النتائج أفضل حجم مفاعل يمكن استخدامه م . 1.2بقطر الكلمات الدالة: نموذج رياضي, افضل المعامالت الحركية, افضل الظروف التشغيلية, توسيع نطاق, مفاعل دفعي available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.21 no.2 (june 2020) 37 – 45 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: nashwan h. yousif , email: nashwanhassan11@gmail.com , name: hussain m. flayeh, email: hussmf200211@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. process optimization study of pb(ii) removal by bulk liquid membrane (blm) nashwan h. yousif and hussain m. flayeh college of engineering, university of baghdad, baghdad, iraq abstract box-wilson experimental design method was employed to optimized lead ions removal efficiency by bulk liquid membrane (blm) method. the optimization procedure was primarily based on four impartial relevant parameters: ph of feed phase (4-6), ph of stripping phase (9-11), carrier concentration tbp (5-10) %, and initial metal concentration (60-120 ppm). a maximum recovery efficiency of lead ions is 83.852% was virtually done following thirty one-of-a-kind experimental runs, as exact through 2 4 -central composite design (ccd). the best values for the aforementioned four parameters, corresponding to the most restoration efficiency were: 5, 10, 7.5% (v/v), and 90 mg/l, respectively. the obtained experimental data had been utilized to strengthen a semi-empirical model, based on a second-degree polynomial, to predict recovery efficiency. the model was tested using anova software (design expert®) and found acceptable r-squared were (0.9673). yield response surface and contour plots have been created using the developed model, which revealed the presence of high-recovery plateaus whose specs will be useful in controlling pilot or industrial scale future devices to ensure economic feasibility. keywords: lead ions, xylene oil, response surface methodology, analysis of variance. received on 26/11/2019, accepted on 20/01/2020, published on 30/06/2020 https://doi.org/10.31699/ijcpe.2020.2.5 1introduction pollution of water by toxic pollutants is one of the most serious troubles in the treatment of industrial wastewater, which has been studied by way of many researchers for many years [1, 2]. exposure to heavy metals has direct and serious consequences toxicity to human health and the environment [3]. industrial wastewater always contains heavy metals like lead, nickel, cadmium etc. from anthropogenic industries, such as petrochemicals, mining activities, batteries, pulp, paper, alloys, steel, pigment paint and fertilizer [4] [5]. most techniques can be employed to remove toxic contaminates from synthetic wastewater such as solvent extraction, bio sorption, chemical precipitation, coagulation [5], ion-exchange, adsorption [6], electrolysis [7], membrane filtration [8], adsorption [9, 10] etc. these techniques have various disadvantages for example, sensitive operating conditions, high capital and operating costs, low selectivity, less efficiency, provide considerable amount of sludge, and further the disposal is a costly fair [11, 12]. hence, more effective treatment techniques are sought after to overcome these difficulties. recently, separation techniques such as liquid membrane, invented by li [2] in 1968, have been widely used for heavy metals separation from industrial wastes [13]. a few advantages of liquid membrane such as high purification ease of operation, high selectivity high throughput, clean-up efficiency and the requirement of only small quantities of organic solvent [14] [15] [16]. among between types of liquid membrane, bulk liquid membrane (blm), is the most well-known and the simplest design for performing liquid membrane processes [17]. a bulk liquid membrane (blm) consists of the feed and stripping phases separated by membrane organic, water immiscible liquid phase [16]. researchers have studied the few parameters affecting the separation efficiency, such as effect of ph on the feed and stripping phases, organic to aqueous phase ratio, mixing time, initial concentrations, carrier concentration, salt concentration, etc. [17, 18]. most of them studied one factor at a time. in actual, this method would possibly no longer reach the actual greatest stipulations [19]. to overcome this problem, the current work utilizes experimental design methods centered composite design (ccd) and response surface methodology (rsm) to look at of different parameters for the best lead ions extraction from synthetic wastewater. the benefits of design experimental consist of simultaneous study of several variables, low cost, faster to implement and convenient [20]. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:nashwanhassan11@gmail.com mailto:hussmf200211@yahoo.com http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2020.2.5 n. h. yousif and h. m. flayeh / iraqi journal of chemical and petroleum engineering 21,2 (2020) 37 45 38 to our knowledge, there has not longer been any work on the use of statistical methods to optimized the procedure parameters of pb(ii) extraction through natural solvents such as xylene oil. the aim of this study is to adopt box-wilson design to optimize the process parameters: ph-feed phase, ph receiving phase, carrier concentration, and initial feed concentration for maximum lead ions removal efficiency by bulk liquid membrane (blm) method. ccd design was utilized to reveal the impact and relation among technique parameters to attain the aforementioned goal. 2material and methods 2.1. material and equipment lead nitrate (pb(no3)2) (99%, purity) (cdh chemicals ltd company, india) was used in feed phase. xylene oil (ch3)2c6h4 (98% purity) and tri-n-butyl phosphate (tbp) (99% purity) was used in membrane phase. sodium hydroxide (naoh) (98% purity), hydrochloric acid (hcl) (98% purity) was used to adjust ph in feed and stripping phases. a hotplate magnetic stirrer (ika, germany) (30120 rpm) was used to combine the carrier and solvent organic, while a ph meters (wtw, germany) used for ph measurement in stripping and feed phases. the concentration of pb(ii) in feed and striping phases was once decided with a flame atomic absorption spectrophotometer, aas: (gbc, germany). 2.2. preparation of aqueous and organic phases fig. 1 suggests the schemetic daigram of the blm system used in this study. it consists of three phases, namely, feed phase, stripping phase and membrane phase. both of the feed and striping phases are separated with a strong impermeable wall and layered on top by way of the membrane phase. an aqueous feed phase of various initial lead ions concentrations was prepared in distilled water. while, an aqueous strip phase containing distilled water. finally, the organic membrane phases were prepared by loading tri-n-butyl phosphate (tbp) as a carrier dissolved in xylene oil. the ph of feed and stripping phases was adjusted to the desired value by adding drops of naoh or hcl. extraction percentage (% e) of heavy metals was calculated according to eq (1): % e = c f0 −cf cf0 × 100 (1) where: c𝐹0 and cf are the initial and final concentrations in the feed phase, respectively. on the other hand, recovery percentage (% s) of pb(ii), was calculated by eq. (2): % s = cs cf0 −cf × 100 (2) where: cs is the final concentration in the striping phase. during the anelysis, the preliminary concentretions of pb(ii) in each the membrane and stripping phases were asseumed zero. fig. 1. bulk liquid membrane system used in this work 3design of experiment 3.1. central composite design ever since the introduction of central composite design by wilson and box in 1951, it has been the most widely accepted and used experimental design for the first order and second order models [21]. there are four factors considered in this research. central composite design (ccd) was used as a method to screen out factors that were statistically important [22]. these important parameters, namely ph feed (4-6), ph stripping (9-11), initial concentration of metal ions (60-120) and carrier concentration (tbp) (5-10), in order to determine the superior conditions for lead ions removal from synthetic wastewater. the variable was coded according to the eq (3). xi = xi−x0 δxi (3) where: xi is the coded variable, xi the real value of an independent variable, x0 the midpoint value of the 𝑖 variable range and δxi he difference of the limiting two values of the 𝑖 variable. the step size is the half value of the difference. the total number of design experiments is given by the eq. (4): 𝑁 = 𝑛𝑗 + 𝑛𝑎 + 𝑛0 = 2 𝐾 + 2𝐾 + 𝑛0 (4) where: 𝑁 is the total number of design experiments, 𝑛0 is number of center points, 𝑛𝑗 is number of star points (𝑛𝑗 = 2 𝐾 ) and 𝑛𝛼 is number of axial points ( 𝑛𝑎 = 2𝐾). the factorial design have two axial points on the axis of each design variable at a distance of 𝑎 = ±√𝐾. in this study there are 4 variables, that means (𝐾 = 4). thus, (𝑛𝑗 = 2 𝐾 = 16), (𝑛𝑎 = 2(4) = 8), 𝑛0 for this design is taken as 6, 𝑎 = ±√4 = 2, and 𝑁 = 30 experiments. the names and levels of the 4 indepandent method parameter, upon which 30 experiments of the ccd matrix have been based, are proven in table 1 whereas the real and coded range and level value of these variables are given in table 2. n. h. yousif and h. m. flayeh / iraqi journal of chemical and petroleum engineering 21,2 (2020) 37 45 39 table 1. names and levels of process factor (parameters) parameters symbol units lead low high ph feed a …. 4 6 ph stripping b ….. 9 11 initial concentration c mg/l 60 120 carrier concentration d % 5 10 table 2. real and coded ranges and levels values for independent variables independent parameter lead coded real levels -2 -1 0 +1 +2 ph feed 3 4 5 6 7 ph stripping 8 9 10 11 12 initial concentration 30 60 90 120 150 carrier concentration 2.5 5 7.5 10 12.5 3.2. fitting a second-order response surface when there is a curvature in the response surface the first order model is insufficient. therefore, second order model is beneficial in approximating a portion of the true response surface with curvature. the second order model consists of all the terms in the first order model, and quadratic and cross product terms. it is generally represented as eq. (5): 𝑌 = 𝛽0 + ∑ 𝛽𝑖 𝑥𝑖 + ∑ 𝛽𝑖𝑖 𝑥𝑖 2 + ∑ ∑ 𝛽𝑖𝑗 𝑥𝑖 𝑥𝑗 + 𝜀 𝑘 𝑗=2 𝑘−1 𝑖=1 𝑘 𝑖=1 𝑘 𝑖=1 (5) where: y is the predicted response (% lead ions removal), 𝛽0 is the intercept (offset) term, 𝛽𝑖 , 𝛽𝑖𝑖 , 𝛽𝑖𝑗 are the firstorder, quadratic and cross-products of x1, x2, x3 and x4 on response, 𝑥𝑖 and 𝑥𝑗 are variables, 𝑖 and 𝑗 are the index numbers for a parameters, k is the number of factors and 𝜀 is the residual [23]. 4results and discussion 4.1. design matrix used and responses measured response surface methods are models and designs for working with continuous treatments when finding the optimal or describing the response is the goal [24]. table 3 shows the design matrix of ccd used in this work. according to 2 4 – ccd, 30 trial runs were adjusted for lead ions removal in the mono-system which are composed of 16 factorial factors (std order 1–16), 8 axial points (std order 17–24) and 6 replicates of the center point (std order 25–30). the table included two readings for the heavy metals removal; experimental and predicted removal. the experimental removal come from the experimental work according to suggested conditions by design expert ®11 to independent variables. while the predicted removal come from analysis of data by using the anova. after the statistical parameters were estimated for all the readings, the fitting equation was obtained as follow (6): removal of pb+2 = 81.83 + 0.69 (𝐴) − 0.93 (𝐵) + 2.22 (𝐶) − 3.78 (𝐷) + 1.06 (𝐴𝐵) + 0.77 (𝐴𝐶) + 0.5(𝐴𝐷) + 0.85 (𝐵𝐶) − 1.12 (𝐵𝐷) − 0.091 (𝐶𝐷) − 2.08 (𝐴2) − 1.49 (𝐵2) − 3.28 (𝐶2) − 4.84 (𝐷2) (6) in eq. (6) the high quality coefficients show the compatible effects on the responses while the negative coefficients show their incompatible effects. the adequacy of these models used to be assessed and they have been determined to be statistically ample from analysis of variance. for %r model (eq. 6), coefficient of determination (r 2 ) and adjusted r 2 (r 2 adj) of 0.9673and 0.9368 were obtained. the lack-of-fit of these models were additionally assessed and it was determined to be significant. table 3 shows the design matrix of ccd used and the average response %removal measured in this work. it consists of a complete of 30 runs which have been performed randomly to keep away from the effect of the uncontrolled factors. all experiments have been carried out under homogeneous condition in one block of measurement. the %r was found to vary from (55.554– 83.85%). the readings show a good matching between results experimental and predicted for lead ions. the quadratic model equations were developed by anova for the extraction and stripping efficiencies. the analysis of variance (anova) showed magnitude of the model f-test (31.72) and p-value (< 0.0001) for pb(ii), respectively, implies the model is significant fit. furthermore, the lack of fit sum of squares was (36.24) and their r-squared were (0.9673), respectively, which are acceptable. values of probability (f < 0.05) indicate model terms are significant, while, values greater than 0.1, which confirm that the model terms are not significant. n. h. yousif and h. m. flayeh / iraqi journal of chemical and petroleum engineering 21,2 (2020) 37 45 40 table 3. number of runs, experimental and predictable values of lead ions run coded values actual values response x1 x2 x3 x4 a: ph f b: ph s c: in conc. mg/l d: carrier conc. % experimental r. of pb (%) predicted r. of pb (%) 1 0 0 0 0 5 10 90 7.5 82.659 81.83 2 1 1 1 -1 6 11 120 5 71.528 71.731 3 0 0 0 0 5 10 90 7.5 82.659 81.83 4 -1 1 -1 -1 4 11 60 5 63.528 62.909 5 0 0 0 0 5 10 90 7.5 81.734 81.83 6 -1 -1 1 -1 4 9 120 5 67.178 67.731 7 -1 -1 -1 -1 4 9 60 5 66.983 66.349 8 -2 0 0 0 3 10 90 7.5 72.638 72.13 9 -1 1 -1 1 4 11 60 10 68.329 67.411 10 1 -1 1 1 6 9 120 10 79.502 78.149 11 1 1 -1 1 6 11 60 10 70.865 70.371 12 1 -1 -1 -1 6 9 60 5 64.331 63.069 13 0 2 0 0 5 12 90 7.5 75.185 74.01 14 0 0 0 0 5 10 90 7.5 80.047 81.83 15 0 0 2 0 5 10 150 7.5 76.462 73.15 16 0 0 0 0 5 10 90 7.5 83.852 81.83 17 -1 -1 1 1 4 9 120 10 76.22 76.349 18 0 0 0 2 5 10 90 12.5 69.931 70.03 19 1 -1 -1 1 6 9 60 10 75.465 74.051 20 0 0 -2 0 5 10 30 7.5 61.446 64.27 21 0 -2 0 0 5 8 90 7.5 77.074 77.73 22 0 0 0 0 5 10 90 7.5 80.047 81.83 23 1 1 1 1 6 11 120 10 76.749 77.869 24 -1 1 1 1 4 11 120 10 70.502 71.829 25 -1 1 1 -1 4 11 120 5 65.815 67.691 26 1 -1 1 -1 6 9 120 5 66.157 67.531 27 2 0 0 0 7 10 90 7.5 74.907 74.89 28 -1 -1 -1 1 4 9 60 10 75.465 75.331 29 0 0 0 -2 5 10 90 2.5 55.554 54.91 30 1 1 -1 -1 6 11 60 5 63.528 63.869 n. h. yousif and h. m. flayeh / iraqi journal of chemical and petroleum engineering 21,2 (2020) 37 45 41 the "pred r-squared" of (0.8465) is in reasonable agreement with the "adj r-squared" of (0.9368), respectively. adequate precision measures the signal-to noise ratio. a ratio greater than 4 is desirable. the ratio of (21.265) indicates an adequate signal for lead ions, respectively. therefore, this model can be used to navigate the design space. 4.2. graphical analysis the response surface method has been used to analyze the three-dimensional response plot produced from the effect of all the process variables on pb +2 by bulk liquid membrane from aqueous solution. it is evident from the anova table that all the individual process variables are significant in increasing the effectiveness of the percentage removal (y). the first purpose for response surface method is to discover the highest quality response. when, there is greater than one response then it is essential to locate the compromise ideal that does not optimize only one response [24]. when there are constraints on the design data, then the experimental plan has to meet necessities of the constraints. the 2nd goal is to understand how the response adjustments in a given course via adjusting the design variables. in general, the response surface can be visualized graphically. the layout is helpful to see the form of a response surface; hills, valleys, and ridge lines. hence, the characteristic f (x1, x2) can be plotted versus the levels of x1 and x2 as shown in figures 2-7 [25]. the resulting graphics gave an excellent clarification for the effects of ph feed and ph stripping, initial metals concentration and carrier concentration. fig. 2-7 illustrates the collective effect of all the independent parameters on the percentage removal of pb +2 . all of the values on the axis of the figures represent the real values. a. effect of ph feed and ph stripping fig. 2 shows the interacting effect of the feed phase ph (x1) and striping phase ph (x2) are play major role in lead ions pb +2 removal at 5 hr. this dimensional plan shows the response surface from the facet and it is called a response surface plot. sometimes, it is less difficult to view the response surface in two-dimensional graphs. the contour plots can show contour strains of x1 and x2 pairs that have the same response value y. the high-removal efficiency plateau exists in the surface over a ph feed range of (4.9-5.3) and a ph stripping range of (9.5-10) for pb (ii) respectively. in the mildly condition, metal ions are ionized and cations pb +2 are available in the feed phase for subsequent complexation at feed membrane interface. thus, a ph gradient between the source and the receiving phases is the driving force for the transport of pb +2 through the liquid membrane. therefore, it is needed that ph of the stripping phase is higher than ph of the feed phase for the effective transport efficiency [26-27]. fig. 2. response surface plot, contour plot of the interacting effects of ph feed and ph stripping on lead removal b. effect of ph feed and initial metals concentration fig. 3 demonstrates the mutual effect of ph feed and inetial metals concentretion on the removal efficeincy for pb (ii) for the mono-system, as a response surface and contour plot. the mass transfer rate of lead ions is increased with increasing initial feed concentration of metal ions in the aqueous phase at optimum ph and concentration. where, the maximum recovery efficiency appears over a ph feed range of (4.92-5.28) and initial metals concentration range of (89.25-103.75 mg/l), respectively. however, the percentage transport of lead ions decreases with increasing initial concentration, may be due to the driving force for the metal ions transport between the aqueous phases remains low. fig. 3. interacting effects of ph feed and initial metals concentration on lead removal: surface plot; contour plot n. h. yousif and h. m. flayeh / iraqi journal of chemical and petroleum engineering 21,2 (2020) 37 45 42 c. effect of ph feed and carrier concentration fig. 4 shows that maximum lead ions removal efficiency plateau exists in the surface for the mono-pb (ii) system, as a response surface and contour plot, over ph feed range of (5.06-5.23) and carrier concentration range of (8.38-8.85 %) (v/v), respectively. that effectiveness of membrane transport will increase as carrier concentration increases and gets saturated at some point and after that carrier concentration delays diffusion rate as viscosity of membrane increases [17]. where, in presence of a carrier as (tbp) in the membrane phase, a metal-carrier complex (pb-tbp complex in this case) is formed at the feed membrane interface which results in the increase of mass transfer rate through the interface and hence higher separation is achieved. on the other hand, at higher ph values there was a decrease in the transport rate of lead ions this decline can be due to a decrease in the hydrogen ion concentration with increasing ph which can cause a decline in the formation of the carrier and the metal ions complex, due to the resulting in the increase in the solubility of tbp in the aqueous feed phase main to the membrane bleeding [30, 31]. fig. 4. interacting effects of ph feed and carrier concentration on lead removal: surface plot; contour plot d. effect of ph stripping and initial metals concentration in fig. 5 the combined interaction of effect of ph stripping and initial metal concentration on lead ions removal efficiency in the mono-pb`(ii) system is shown, as a response surface and contour plot. where, the effect of ph of the stripping phase and initial concentration on the receiving of lead ions at aqueous phase through bulk liquid membrane, was measured within the range ph stripping phase from (4 to 12) and (40 to 150ppm) for initial concentration, respectively. as shown, the highremoval efficiency plateau corresponds to effect of ph stripping range of (9.66–9.89) and initial metals concentration range of (91.25–99.47 mg/l), respectively. observed, that membrane phase rapidly got saturated with the metal ions concentration affecting mass transfer. therefore, the significant decrease in the stripping efficiency, located at lower and higher ph values could be related to the decreased decompiling ability of carrier between the membrane and stripping interface [32, 33]. fig. 5. interacting effects of ph stripping and initial metals concentration on lead removal: surface plot; contour plot e. effect of ph stripping and carrier concentration it is obvious from the observed results in fig. 6. the effect of ph stripping and carrier concentration on the efficiency of lead ions removal for the mono-pb (ii) system, as a contour plot and response surface, is presented. it can be found that a high-removal efficiency plateau exists in the surface over effect of ph stripping range of (9.45–9.79) and a carrier concentration range of (8.09–9.17) % (v/v), respectively. the decrease of recovery efficiency at lower and higher ph values lead to due to the saturation of driving force for diffusion through xylene oil based bulk liquid membrane due to the complex formed by the tbp effect in the organic membrane at optimum carrier. it observed at lower and higher ph value could be associated to the reduced decompiling capacity of carrier between the membrane and stripping interface [28]. fig. 6. interacting effects of ph stripping and carrier concentration on lead removal: surface plot; contour plot f. effect of initial metals concentration and carrier concentration the effect of initial metals concentration and carrier concentration on the transport efficiency for lead ions for the mono-pb(ii) system, as a response surface and contour plot, is presented by means of fig. 7. n. h. yousif and h. m. flayeh / iraqi journal of chemical and petroleum engineering 21,2 (2020) 37 45 43 it can be observed that a high-removal efficiency plateau exists in the surface over an initial metals concentration range of (91.11-99.23 mg/l) and a carrier concentration range of (8.37-8.94) % (v/v) for pb(ii), respectively. it may be due to the competition between lead ions at very high concentrations; therefore, the organic extracting (carrier) cannot able to transport the metal ions from the aqueous source phase to receiving phases [29]. fig. 7. interacting effects of initial metals concentration and carrier concentration on lead removal: surface plot; contour plot 5conclusion in the present study, four variables central composite design based the response surface method (rsm) has been employed to investigate the individual as well as the combined effect of independent variables on lead removal by bulk liquid membrane from aqueous solution. the study revealed that all the parameters, i.e., ph feed and stripping phases, initial metals concentration and carrier concentration. individually affect the blm process significantly compared to the combined effect. with the help of design expert, the regression analysis and variables optimization were calculated to predict the significant response in the experimental domain. a large number of experimental data at a wide range of independent variables were employed to carry out the regression analysis, statistical importance, and response surface analysis. a simple second order quadratic model equation was developed using design expert software for predicting the response (percentage removal of pb (ii)) on overall experimental regions and correlate the operating parameters and removal efficiency of pb (ii). the coefficients of the developed model were calculated for each response, and the high acceptability of the postulated model was proven by presenting the statistical specifications of them. the reliability of the developed model has been ensured from the high magnitude of the correlation coefficient r2 (0.9673) and r2 (adj) (0.9368)) between the experimental and model predicted values. the response surface was derived based on the developed model. ph feed and stripping phase was found as the most significant factor among all the process variables. the optimum condition for maximum pb (ii) removal was: feed phase ph 5, stripping phase ph 10, carrier concentration 7.5 %(v/v), and initial concentration 90 ppm. the experimental recovery efficiency 83.852% obtained under the optimum operating conditions agrees well with the predicted recovery efficiency one 81.83%. references [1] n. balkaya and n. bektas, "chromium(vi) sorption from dilute aqueous solutions using wool", desalination and water treatment, vol. 3, pp. 43–49, 2009. [2] n.a. oladoja, a.e. ofomaja, j.a. idiaghe, a.k. akinlabi and e.e. egbon, "sorption of cu (ii) ion from aqueous solution by scrap tyre", desalination and water treatment, vol. 16, pp. 83–94, 2010. [3] t.a. kurniawan, y.s.g. chan, w. lo, s. babel, "physico-chemical treatment techniques for wastewater laden with heavy metals," chem. eng. j, vol. 118, pp. 83–98, 2006. [4] c. f. carolin1, p. s. kumar1, a. saravanan1, g. j. joshiba, and mu. naushad, "efficient techniques for the removal of toxic heavy metals from aquatic environment", journal of environmental chemical engineering, 2017. [5] h. m. salman, and a. a. mohammed, "removal of copper ions from aqueous solution using liquid surfactant membrane technique", iraqi journal of chemical and petroleum engineering, vol. 20, no. 3, pp. 31 – 37, 2019. [6] a. azimi, a. azari, m. rezakazemi, and m ansarpour, "removal of heavy metals from industrial wastewaters", chembioeng rev, vol. 4, 1, pp. 37– 59, 2017. [7] k. h. park, p. k. parhi, and nam-hee kang, "studies on removal of low content copper from the sea nodule aqueous solution using the cationic resin tp 207", separation science and technology, vol. 47, pp. 1531–1541, 2012. [8] y. bo, w. cheng-yan, l. dun-fang, y. fei, chen yong-qiang, and w. nian-wei, "selective separation of copper and cadmium from zinc solutions by low current density electrolysis", trans. nonferrous met. soc. china, vol. 20, pp. 533-536, 2010. [9] benoit guieysse, zane n. norvill sequential chemical–biological processes for the treatment of industrial wastewaters: review of recent progresses and critical assessment. journal of hazardous materials 267 (2014) 142– 152, 2014. [10] l. a. naji, s. h. jassam, m. j. yaseen, a. a. h. faisal and n. al-ansari. "modification of langmuir model for simulating initial ph and temperature effects on sorption process", separation science and technology, 2019. https://www.tandfonline.com/doi/abs/10.5004/dwt.2009.473 https://www.tandfonline.com/doi/abs/10.5004/dwt.2009.473 https://www.tandfonline.com/doi/abs/10.5004/dwt.2009.473 https://www.tandfonline.com/doi/abs/10.5004/dwt.2009.473 https://www.tandfonline.com/doi/abs/10.5004/dwt.2010.1071 https://www.tandfonline.com/doi/abs/10.5004/dwt.2010.1071 https://www.tandfonline.com/doi/abs/10.5004/dwt.2010.1071 https://www.tandfonline.com/doi/abs/10.5004/dwt.2010.1071 https://www.sciencedirect.com/science/article/abs/pii/s1385894706000362 https://www.sciencedirect.com/science/article/abs/pii/s1385894706000362 https://www.sciencedirect.com/science/article/abs/pii/s1385894706000362 https://www.sciencedirect.com/science/article/abs/pii/s1385894706000362 https://www.sciencedirect.com/science/article/abs/pii/s2213343717302208 https://www.sciencedirect.com/science/article/abs/pii/s2213343717302208 https://www.sciencedirect.com/science/article/abs/pii/s2213343717302208 https://www.sciencedirect.com/science/article/abs/pii/s2213343717302208 https://www.sciencedirect.com/science/article/abs/pii/s2213343717302208 https://doi.org/10.31699/ijcpe.2019.3.5 https://doi.org/10.31699/ijcpe.2019.3.5 https://doi.org/10.31699/ijcpe.2019.3.5 https://doi.org/10.31699/ijcpe.2019.3.5 https://doi.org/10.31699/ijcpe.2019.3.5 https://onlinelibrary.wiley.com/doi/abs/10.1002/cben.201600010 https://onlinelibrary.wiley.com/doi/abs/10.1002/cben.201600010 https://onlinelibrary.wiley.com/doi/abs/10.1002/cben.201600010 https://onlinelibrary.wiley.com/doi/abs/10.1002/cben.201600010 https://www.tandfonline.com/doi/abs/10.1080/01496395.2011.652285 https://www.tandfonline.com/doi/abs/10.1080/01496395.2011.652285 https://www.tandfonline.com/doi/abs/10.1080/01496395.2011.652285 https://www.tandfonline.com/doi/abs/10.1080/01496395.2011.652285 https://www.tandfonline.com/doi/abs/10.1080/01496395.2011.652285 https://www.sciencedirect.com/science/article/abs/pii/s1003632609601746 https://www.sciencedirect.com/science/article/abs/pii/s1003632609601746 https://www.sciencedirect.com/science/article/abs/pii/s1003632609601746 https://www.sciencedirect.com/science/article/abs/pii/s1003632609601746 https://www.sciencedirect.com/science/article/abs/pii/s1003632609601746 https://www.sciencedirect.com/science/article/abs/pii/s0304389413009394 https://www.sciencedirect.com/science/article/abs/pii/s0304389413009394 https://www.sciencedirect.com/science/article/abs/pii/s0304389413009394 https://www.sciencedirect.com/science/article/abs/pii/s0304389413009394 https://www.sciencedirect.com/science/article/abs/pii/s0304389413009394 https://www.tandfonline.com/doi/full/10.1080/01496395.2019.1655055 https://www.tandfonline.com/doi/full/10.1080/01496395.2019.1655055 https://www.tandfonline.com/doi/full/10.1080/01496395.2019.1655055 https://www.tandfonline.com/doi/full/10.1080/01496395.2019.1655055 https://www.tandfonline.com/doi/full/10.1080/01496395.2019.1655055 n. h. yousif and h. m. flayeh / iraqi journal of chemical and petroleum engineering 21,2 (2020) 37 45 44 [11] z. t. a. ali, laith a. najia, s. a. a. a. n. almuktarb, a. a. h. faisala, s. n. abedc, m. scholzc, m. naushadf, and t. ahamadf, "predominant mechanisms for the removal of nickel metal ion from aqueous solution using cement kiln dust", journal of water process engineering vol. 33, 2020. [12] t. a. kurniawan, g. y. s. chan, w. h. lo, and s. babel, “physico-chemical treatment techniques for wastewater laden with heavy metals,” chemical engineering journal, vol. 118, no. 1-2, pp. 83–98, 2006. [13] s. s. ahluwalia and d. goyal, “removal of heavy metals by waste tea leaves from aqueous solution,” engineering in life sciences, vol. 5, no. 2, pp. 158–162, 2005. [14] k. m. abed and a. al-hemiri,“separation of alkaloids from plants by bulk liquid membrane technique using rotating discs contactor,” diyala journal of engineering sciences, second engineering scientific conference college of engineering – university of diyala 16-17 december , pp. 785-793, 2015. [15] a. w. al-shahwany, a. a. al-hemiri and k. m. abed, “comparative evaluation of alkaloids extraction methods from the root bark of punica granatum linn,” advances in bioresearch vol. 4 (1), pp. 3339, 2013. [16] a. talebi, t. t. teng, a. f. m. alkarkhi, i. norli, and l. w. low, "optimization of nickel removal using liquid–liquid extraction and response surface methodology," desalination and water treatment, vol. 47, pp. 334–340, 2012. [17] a. a. al-hemiri, k. m. abed, and a. w. alshahwany, "extraction of pelletierine from punica granatum l.by liquid membrane technique and modelling", iraqi journal of chemical and petroleum engineering vol. 13, no.1, 19, 2012. [18] k. m. abed, "kinetic of alkaloids extraction from plant by batch pertraction in rotating discs contacto," iraqi journal of chemical and petroleum engineering, vol. 15 no.2, pp. 7584, 2014. [19] v. s. kislik, "liquid membranes: principles and applications in chemical separations and wastewater treatment", elsevier: amsterdam, 2009. [20] d. darvishia, d. f. haghshenasa, e. k. alamdarib, t. s. k. sadrnezhaada, and m. halalia, "synergistic effect of cyanex 272 and cyanex 302 on separation of cobalt and nickel by d2ehpa". hydrometallurgy, vol. 77, pp.227–238, 2005. [21] s. h. changa, t. t. tengb, n. ismailb, a. f. m. alkarkhib, "selection of design parameters and optimization of operating parameters of soybean oilbased bulk liquid membrane for cu(ii) removal and recovery from aqueous solutions. " journal of hazardous materials, vol. 190, pp.197–204, 2011. [22] l.w. low, t.t. teng, f.m. abbas alkarkhi, a. ahmad, m. norhashimah, "optimization of the adsorption conditions for the decolorization and cod reduction of methylene blue aqueous solution using low-cost adsorbent, " water air soil pollut, vol. 214, pp. 185–195, 2011. [23] m. a. bezerraa, r. e. santelli, e. p. oliveiraa, l. s. villar, and l. a. escaleiraa,"response surface methodology (rsm) as a tool for optimization in analytical chemistry", talanta, vol. 76 pp. 965–977, 2008. [24] s. h. chang, t. t. teng, and n. ismail. "optimization of cu(ii) extraction from aqueous solutions by soybean-oil-based organic solvent using response surface methodology". water air soil pollut, vol. 217, pp. 567–576, 2011. [25] p. angelopoulos, h. evangelaras, and c. koukouvinos, "small, balanced, efficient and near rotatable central composite designs", journal of statistical planning and inference, vol. 139, pp 20102013, 2009. [26] h. s. kusuma, r. g. m. sudrajat, d. f. susanto, s. gala, and m. mahfud, "response surface methodology (rsm) modeling of microwave-assisted extraction of natural dye from swietenia mahagony: a comparation between box behnken and central composite design method," international conference of chemical and material engineering(iccme), 2015. [27] oehlert, and w. gary, "design and analysis of experiments: response surface design", new york: w.h. freeman and company, 2000. [28] montgomery, and c. douglas, "design and analysis of experiments: response surface method and designs", new jersey: john wiley and sons inc, 2017. [29] s. biswas, "separation of chromium (vi) by bulk liquid membrane technique", national institute of technology rourkela may, 2015. [30] w. zhang, j. liu, z. ren, s. wang, c. du and j. ma, “kinetic study of chromium(vi) facilitated transport through a bulk liquid membrane using tri-nbutyl phosphate as carrier.” chemical engineering journal, vol. 150, pp 83–89, 2009. [31] a. talebi, t. t. teng, f. m. a. abbas, i. norli and l.w. low, “optimization of nickel removal using liquid–liquid extraction and response surface methodology,” desalination and water treatment, vol. 47, pp. 334–340, 2012. [32] a. b. shaik, k. c, p. saha, and a. k. ghoshal, "separation of hg(ii) from its aqueous solution using bulk liquid membrane," ind. eng. chem, vol. 49, pp. 2889–2894, 2010. [33] g. muthuraman, t. t. teng, c. p. leh, and i. norli, "use of bulk liquid membrane for the removal of chromium (vi) from aqueous acidic solution with tri-n-butyl phosphate as a carrier", desalination, vol. 249, pp. 884–890, 2009. https://www.sciencedirect.com/science/article/pii/s2214714419312371 https://www.sciencedirect.com/science/article/pii/s2214714419312371 https://www.sciencedirect.com/science/article/pii/s2214714419312371 https://www.sciencedirect.com/science/article/pii/s2214714419312371 https://www.sciencedirect.com/science/article/pii/s2214714419312371 https://www.sciencedirect.com/science/article/pii/s2214714419312371 https://www.sciencedirect.com/science/article/abs/pii/s1385894706000362 https://www.sciencedirect.com/science/article/abs/pii/s1385894706000362 https://www.sciencedirect.com/science/article/abs/pii/s1385894706000362 https://www.sciencedirect.com/science/article/abs/pii/s1385894706000362 https://www.sciencedirect.com/science/article/abs/pii/s1385894706000362 https://onlinelibrary.wiley.com/doi/abs/10.1002/elsc.200420066 https://onlinelibrary.wiley.com/doi/abs/10.1002/elsc.200420066 https://onlinelibrary.wiley.com/doi/abs/10.1002/elsc.200420066 https://onlinelibrary.wiley.com/doi/abs/10.1002/elsc.200420066 https://dengs.iraqjournals.com/article_109703.html https://dengs.iraqjournals.com/article_109703.html https://dengs.iraqjournals.com/article_109703.html https://dengs.iraqjournals.com/article_109703.html https://dengs.iraqjournals.com/article_109703.html https://dengs.iraqjournals.com/article_109703.html https://dengs.iraqjournals.com/article_109703.html https://www.researchgate.net/profile/ayyad_al_shahwany2/publication/299410218_comparative_evaluation_of_alkaloids_extraction_methods_from_the_root_bark_of_punica_granatum_linn/links/56f4b1b408ae81582bf0a6ad.pdf https://www.researchgate.net/profile/ayyad_al_shahwany2/publication/299410218_comparative_evaluation_of_alkaloids_extraction_methods_from_the_root_bark_of_punica_granatum_linn/links/56f4b1b408ae81582bf0a6ad.pdf https://www.researchgate.net/profile/ayyad_al_shahwany2/publication/299410218_comparative_evaluation_of_alkaloids_extraction_methods_from_the_root_bark_of_punica_granatum_linn/links/56f4b1b408ae81582bf0a6ad.pdf https://www.researchgate.net/profile/ayyad_al_shahwany2/publication/299410218_comparative_evaluation_of_alkaloids_extraction_methods_from_the_root_bark_of_punica_granatum_linn/links/56f4b1b408ae81582bf0a6ad.pdf https://www.researchgate.net/profile/ayyad_al_shahwany2/publication/299410218_comparative_evaluation_of_alkaloids_extraction_methods_from_the_root_bark_of_punica_granatum_linn/links/56f4b1b408ae81582bf0a6ad.pdf https://www.tandfonline.com/doi/abs/10.1080/19443994.2012.696432 https://www.tandfonline.com/doi/abs/10.1080/19443994.2012.696432 https://www.tandfonline.com/doi/abs/10.1080/19443994.2012.696432 https://www.tandfonline.com/doi/abs/10.1080/19443994.2012.696432 https://www.tandfonline.com/doi/abs/10.1080/19443994.2012.696432 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/328 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/328 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/328 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/328 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/328 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/328 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/279 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/279 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/279 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/279 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/279 https://books.google.iq/books?hl=en&lr=&id=2lv-pdcwjsyc&oi=fnd&pg=pp1&dq=v.+s.+kislik,+%22liquid+membranes:+principles+and+applications+in+chemical+separations+and+wastewater+treatment%22,+elsevier:+amsterdam,+2009.+&ots=ovodcp0wls&sig=8ydwwfddyvkv7etezyg6dxjjtbe&redir_esc=y#v=onepage&q=v.%20s.%20kislik%2c%20%22liquid%20membranes%3a%20principles%20and%20applications%20in%20chemical%20separations%20and%20wastewater%20treatment%22%2c%20elsevier%3a%20amsterdam%2c%202009.&f=false https://books.google.iq/books?hl=en&lr=&id=2lv-pdcwjsyc&oi=fnd&pg=pp1&dq=v.+s.+kislik,+%22liquid+membranes:+principles+and+applications+in+chemical+separations+and+wastewater+treatment%22,+elsevier:+amsterdam,+2009.+&ots=ovodcp0wls&sig=8ydwwfddyvkv7etezyg6dxjjtbe&redir_esc=y#v=onepage&q=v.%20s.%20kislik%2c%20%22liquid%20membranes%3a%20principles%20and%20applications%20in%20chemical%20separations%20and%20wastewater%20treatment%22%2c%20elsevier%3a%20amsterdam%2c%202009.&f=false https://books.google.iq/books?hl=en&lr=&id=2lv-pdcwjsyc&oi=fnd&pg=pp1&dq=v.+s.+kislik,+%22liquid+membranes:+principles+and+applications+in+chemical+separations+and+wastewater+treatment%22,+elsevier:+amsterdam,+2009.+&ots=ovodcp0wls&sig=8ydwwfddyvkv7etezyg6dxjjtbe&redir_esc=y#v=onepage&q=v.%20s.%20kislik%2c%20%22liquid%20membranes%3a%20principles%20and%20applications%20in%20chemical%20separations%20and%20wastewater%20treatment%22%2c%20elsevier%3a%20amsterdam%2c%202009.&f=false https://books.google.iq/books?hl=en&lr=&id=2lv-pdcwjsyc&oi=fnd&pg=pp1&dq=v.+s.+kislik,+%22liquid+membranes:+principles+and+applications+in+chemical+separations+and+wastewater+treatment%22,+elsevier:+amsterdam,+2009.+&ots=ovodcp0wls&sig=8ydwwfddyvkv7etezyg6dxjjtbe&redir_esc=y#v=onepage&q=v.%20s.%20kislik%2c%20%22liquid%20membranes%3a%20principles%20and%20applications%20in%20chemical%20separations%20and%20wastewater%20treatment%22%2c%20elsevier%3a%20amsterdam%2c%202009.&f=false https://www.sciencedirect.com/science/article/abs/pii/s0304386x05000460 https://www.sciencedirect.com/science/article/abs/pii/s0304386x05000460 https://www.sciencedirect.com/science/article/abs/pii/s0304386x05000460 https://www.sciencedirect.com/science/article/abs/pii/s0304386x05000460 https://www.sciencedirect.com/science/article/abs/pii/s0304386x05000460 https://www.sciencedirect.com/science/article/abs/pii/s0304389411003281 https://www.sciencedirect.com/science/article/abs/pii/s0304389411003281 https://www.sciencedirect.com/science/article/abs/pii/s0304389411003281 https://www.sciencedirect.com/science/article/abs/pii/s0304389411003281 https://www.sciencedirect.com/science/article/abs/pii/s0304389411003281 https://www.sciencedirect.com/science/article/abs/pii/s0304389411003281 https://link.springer.com/article/10.1007/s11270-010-0414-0 https://link.springer.com/article/10.1007/s11270-010-0414-0 https://link.springer.com/article/10.1007/s11270-010-0414-0 https://link.springer.com/article/10.1007/s11270-010-0414-0 https://link.springer.com/article/10.1007/s11270-010-0414-0 https://link.springer.com/article/10.1007/s11270-010-0414-0 https://www.sciencedirect.com/science/article/abs/pii/s0039914008004050 https://www.sciencedirect.com/science/article/abs/pii/s0039914008004050 https://www.sciencedirect.com/science/article/abs/pii/s0039914008004050 https://www.sciencedirect.com/science/article/abs/pii/s0039914008004050 https://www.sciencedirect.com/science/article/abs/pii/s0039914008004050 https://link.springer.com/article/10.1007/s11270-010-0610-y https://link.springer.com/article/10.1007/s11270-010-0610-y https://link.springer.com/article/10.1007/s11270-010-0610-y https://link.springer.com/article/10.1007/s11270-010-0610-y https://link.springer.com/article/10.1007/s11270-010-0610-y https://www.sciencedirect.com/science/article/abs/pii/s0378375808003686 https://www.sciencedirect.com/science/article/abs/pii/s0378375808003686 https://www.sciencedirect.com/science/article/abs/pii/s0378375808003686 https://www.sciencedirect.com/science/article/abs/pii/s0378375808003686 https://www.sciencedirect.com/science/article/abs/pii/s0378375808003686 https://aip.scitation.org/doi/abs/10.1063/1.4938345 https://aip.scitation.org/doi/abs/10.1063/1.4938345 https://aip.scitation.org/doi/abs/10.1063/1.4938345 https://aip.scitation.org/doi/abs/10.1063/1.4938345 https://aip.scitation.org/doi/abs/10.1063/1.4938345 https://aip.scitation.org/doi/abs/10.1063/1.4938345 https://aip.scitation.org/doi/abs/10.1063/1.4938345 https://aip.scitation.org/doi/abs/10.1063/1.4938345 https://books.google.iq/books?hl=en&lr=&id=py7bdgaaqbaj&oi=fnd&pg=pa1&dq=%5b28%5d%09montgomery,+and+c.+douglas,+%22design+and+analysis+of+experiments:+response+surface+method+and+designs%22,+new+jersey:+john+wiley+and+sons+inc,+2005.&ots=x6y1lzrty9&sig=shpvmbfwkv_xltqsb0nnkdfjsam&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=py7bdgaaqbaj&oi=fnd&pg=pa1&dq=%5b28%5d%09montgomery,+and+c.+douglas,+%22design+and+analysis+of+experiments:+response+surface+method+and+designs%22,+new+jersey:+john+wiley+and+sons+inc,+2005.&ots=x6y1lzrty9&sig=shpvmbfwkv_xltqsb0nnkdfjsam&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=py7bdgaaqbaj&oi=fnd&pg=pa1&dq=%5b28%5d%09montgomery,+and+c.+douglas,+%22design+and+analysis+of+experiments:+response+surface+method+and+designs%22,+new+jersey:+john+wiley+and+sons+inc,+2005.&ots=x6y1lzrty9&sig=shpvmbfwkv_xltqsb0nnkdfjsam&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=py7bdgaaqbaj&oi=fnd&pg=pa1&dq=%5b28%5d%09montgomery,+and+c.+douglas,+%22design+and+analysis+of+experiments:+response+surface+method+and+designs%22,+new+jersey:+john+wiley+and+sons+inc,+2005.&ots=x6y1lzrty9&sig=shpvmbfwkv_xltqsb0nnkdfjsam&redir_esc=y#v=onepage&q&f=false http://ethesis.nitrkl.ac.in/7033/ http://ethesis.nitrkl.ac.in/7033/ http://ethesis.nitrkl.ac.in/7033/ https://www.sciencedirect.com/science/article/abs/pii/s1385894708008152 https://www.sciencedirect.com/science/article/abs/pii/s1385894708008152 https://www.sciencedirect.com/science/article/abs/pii/s1385894708008152 https://www.sciencedirect.com/science/article/abs/pii/s1385894708008152 https://www.sciencedirect.com/science/article/abs/pii/s1385894708008152 https://www.tandfonline.com/doi/abs/10.1080/19443994.2012.696432 https://www.tandfonline.com/doi/abs/10.1080/19443994.2012.696432 https://www.tandfonline.com/doi/abs/10.1080/19443994.2012.696432 https://www.tandfonline.com/doi/abs/10.1080/19443994.2012.696432 https://www.tandfonline.com/doi/abs/10.1080/19443994.2012.696432 https://pubs.acs.org/doi/abs/10.1021/ie901362m https://pubs.acs.org/doi/abs/10.1021/ie901362m https://pubs.acs.org/doi/abs/10.1021/ie901362m https://pubs.acs.org/doi/abs/10.1021/ie901362m https://www.sciencedirect.com/science/article/abs/pii/s0011916409009473 https://www.sciencedirect.com/science/article/abs/pii/s0011916409009473 https://www.sciencedirect.com/science/article/abs/pii/s0011916409009473 https://www.sciencedirect.com/science/article/abs/pii/s0011916409009473 https://www.sciencedirect.com/science/article/abs/pii/s0011916409009473 n. h. yousif and h. m. flayeh / iraqi journal of chemical and petroleum engineering 21,2 (2020) 37 45 45 (mlbاسة عملية التحسين ألزالة أيونات الرصاص بواسطة الغشاء السائل الحجمي )در حسين مجيد فليح و نشوان حسن يوسف قسم الهندسة البيئية، ، بغداد، العراق ,كلية الهندسة, جامعة بغداد الخالصة الرصاص بطريقة الغشاء السائل لتحسين كفاءة أيونات xob-noslowتم استخدام طريقة التصميم التجريبي (. استند أجراء التحسين في المقام األول الى أربع معلمات محايدة ذات صلة وهي درجة xlbالحجمي ) ( % 5-10( وتركيز الناقل )9-11(، ودرجة الحموضة في مرحلة التعرية )4-6الحموضة في مرحلة التغذية ) pxt( تم تحقيق 60-120، وتركيز المعدن األولي .) أقصى استعادة من كفاءة أيونات الرصاص بنسبة . 24تجربة فريدة من نوعها. كما هو دقيق من خالل التصميم المركب المركزي ذي 30% تقريبا بعد 83.852 ( v/v%) 7.5، 10، 5وكانت أفضل القيم للمعلمات المذكورة أعاله، والتي تتوافق مع معظم كفاءة االستعادة، والي. وقد تم استخدام البيانات التجريبية التي تم الحصول عليها لتعزيز نموذج شبه مجم / لتر، على الت 90و جريبي، على أساس متعدد الحدود من الدرجة الثانية للتنبأ بكفاءة االنتعاش. تم اختبار النموذج باستخدام برنامج xrepx olosw bvona ووجد انr-deranos ( تم إنشاء مؤامرات ل0.9673مقبولة .) سطح استجابة الغلة ومحيطها باستخدام النموذج المتطور، والذي كشف عن وجود هضاب عالية االسترداد تكون مواصفاتها مقيدة في التحكم في األجهزة المستقبلية ذات النطاق التجريبي او الصناعي لضمان الجدوى االقتصادية. .التباين تحليل ، سطح استجابة منهجية ، الزايلين زيت ، الرصاص الكلمات الدالة: أيونات iraqi journal of chemical and petroleum engineering vol.13 no.4 (december 2012) 4755 issn: 1997-4884 removal of nickel ions using a biosorbent bed (laminaria saccharina) algae firas hashim kamar al-hamadani institute of technology -baghdad abstract the present study aims to remove nickel ions from solution of the simulated wastewater using (laminaria saccharina) algae as a biosorbent material. effects of experimental parameters such as temperature at (20 40) c⁰, ph at (3 7) at time (10 120) min on the removal efficiency were studied. box-wilson method was adopted to obtain a relationship between the above three experimental parameters and removal percentage of the nickel ions. the experimental data were fitted to second order polynomial model, and the optimum conditions for the removal process of nickel ions were obtained. the highest removal percentage of nickel ions obtained was 98.8 %, at best operating conditions (temperature 35 c⁰, ph 5 and time 10 min). keywords: nickel ions, biosorbent bed, (laminaria saccharina) algae introduction heavy metals are generally considered to be those whose density exceeds 5 g/cm 3 [1]. removal of heavy metals from industrial wastewater is of primary importance because they are not only cause contamination of water bodies but also they are toxic to many life forms. industrial processes generate wastewater containing heavy metal contaminants. since most of heavy metals are nondegradable into nontoxic end products, their concentrations must be reduced to acceptable levels before discharging them into environment. otherwise these could pose threats to public health and/or affect the aesthetic quality of potable water [2]. according to world health organization (who) the metals of most immediate concern are chromium, copper, zinc, iron, nickel, mercury and lead [3]. nickel ions represent a serious environmental problem since they are widely used in many industries and general applications. among them are: industrial effluents, industrial fertilizers, catalysts, gears, magnets, airbag valves, electronics, tooth protects, exhaust smokes, stainless steels, etc. [4]. ni (ii) is a known environmental pollutant and its removal is of major concern because nickel compounds are carcinogenic and also can cause asthma. another common adverse health effect of ni (ii) is skin allergy [5]. the removal of heavy metal ions from aqueous solutions can be iraqi journal of chemical and petroleum engineering university of baghdad college of engineering removal of nickel ions using a biosorbent bed (laminaria saccharina) algae 48 ijcpe vol.13 no.4 (december 2012) -available online at: www.iasj.net achieved by several processes, such as chemical precipitation, biosorption, adsorption, solvent extraction, reduction, coagulation, oxidation, reverse osmosis, flotation, ultra filtration and ion exchange [6, 7, 8]. the search for new technologies involving the removal of toxic metals from wastewaters has directed attention to biosorption, based on metal binding capacities of various biological materials. biosorption can be defined as the ability of biological materials to accumulate heavy metals from wastewater through metabolically mediated or physico-chemical pathways of uptake [9]. algae, bacteria, fungi and yeasts have proved to be potential metal biosorbents [10]. the major advantages of biosorption over conventional treatment methods include [11]: low cost, high efficiency, minimization of chemical and /or biological sludge, no additional nutrient requirement, regeneration of biosorbent and possibility of metal recovery. algae biomass has proven to be highly effective as well as reliable and predictable in the removal of heavy metals from aqueous solution. the term algae refer to a large and diverse assemblage of organisms that contain chlorophyll and carry out oxygenic photosynthesis [12]. there are seven divisions of algae: four of which contain algae as members. divisions which include the large visible algae are: cyanophyta (blue-green algae), clorophyta (green algae), rhodophyta (red algae), and phaeophyta (brown algae). these divisions are subdivided into orders, which are subsequently divided in to families and then into genus and species [13]. sargassum sp. algae was reported to be able to absorb one or more heavy metal ions, including: k, mg, ca, fe, sr, co, cu, mn, ni, zn, as, cd, mo, pb, se, al ions with good metal uptake capacity [14, 15]. laminaria saccharina is a type of brown algae, which is in the form of long grass (0.5 14.0) m and that the dominant form in this type of algae is the form spore. this type of algae is present on the beaches, marine tidal low and at depths of up to 30 m in the shores of the atlantic and pacific and the mediterranean sea [16]. the aim of the present work is to investigate the efficiency of laminaria saccharina algae as biosorbent material to remove nickel ions from solution of simulated wastewater. the effects of temperature, ph, and time on the removal efficiency were studied. experiments and material biosorbent material and chemicals a laminaria saccharina algae were used as biosorbent material for the removal of nickel ions. the algae were collected from al-lattakia from syria in july of 2010. 2000 gm of algae were washed and dried at 105 o c for 24 hrs, then grinded and sieved to obtain 0.75 mm diameter of a biosorbent particales. nickel sulfate hexahydrate niso4.6h2o, m.wt= 262.8486 gm/mol. (ferak, germany) used to prepare a solution of the simulated wastewater contains 10 mg/l of nickel ion (ni +2 ). hydrochloric acid [1m] and sodium hydroxide pellets were used to adjust ph to the desired value. equipment atomic absorption spectrometer: aas (norwalk, connecticut, u.s.a) used to measure concentrations of soluble nickel. ph-meter: the ph of the solution was measured by ph bench meter (i h250, bench model, usa). digital electrical balance (sartorius, 1500 gm capacity and 0. 1 gm firas hashim kamar al-hamadani -available online at: www.iasj.net ijcpe vol.13 no.4 (december 2012) 49 accuracy) used for weighting the materials used in this work. several types of sieves were used to obtain 0.75 mm diameter of a biosorbent particales. preparation of simulated solution generally, to achieve a concentration of 1000 mg/l of simulated wastewater, a mass of heavy metal salt was added to distilled water by assuming complete dissolution and calculated as follows [17]: w = v × ci × …(1) where: w: weight of heavy metal salt (mg). v: volume of solution (1l). ci: initial concentration of metal ions in solution (mg). m.wt: molecular weight of metal salt (g/mole) at.wt: atomic weight of metal ion (g/mole) nickel was added in the form of nickel sulfate hexahydrate (niso4.6h2o). nickel (ni +2 ) has a molecular weight of (58.69) g/mole. to determine the amount of niso4.6h2o necessary to prepare a solution of the simulated wastewater contains (10) mg/l of nickel ions (ni +2 ), the following equation is used: niso4.5h2o (s) ni +2 (aq) + so4 -2 (aq) + 5h2o (l) …(2) w = 1(l) × 10 (mg) × w= 44.8 mg niso4.5h2o a biosorption unit schematic diagram of the biosorption unit is shown in fig. (1) which consist of the following parts: tank: 250 l volume to store the solution of simulated wastewater consists 10 mg/l of nickel ions (ni +2 ). pump, power consumption 1.5 kw / (220 – 240 v) from (haake w19), to pumping the simulated solution at constant volumetric flow rate 1.5 cm 3 /sec. glass column: 100 cm height, 5 cm diameter and 2.5 mm wall thickness. two circular glass discs 5 cm thickness were installed at a distance of 20 cm from the upper and lower end of the glass column. the discs were perforated by 0.5 mm holes maintain a uniform dawn flow of simulated solution. a biosorbent bed: (50 cm height and 5 cm diameter) were made by put (500) gm of dry particle of biosorbent material (0.75 mm particle diameter of laminaria saccharina) between two circular glass discs above. moisture and ash contents of the biosorbent material but also the porosity and bulk density of the bed were determined in accordance of a reference method [17]. some properties of biosorbent material and bed are shows in table (1). table 1, some properties of biosorbent material and bed biosorption process a solution of simulated wastewater in the stored tank was pumped at constant volumetric flow rate 1.5 cm 3 /sec at the top of the column above at temperature (20-40) o c, ph of (3-7) and time (10-120) min. samples of treated water 100 ml were taken from the bottom of column, these samples were filtered and the residual concentration of nickel ions was determined by ass. no. properties value 1moisture 9% 2ash contents 0.5% 3porosity 0.49 4bulk density 0.5 gm./cm 3 removal of nickel ions using a biosorbent bed (laminaria saccharina) algae 50 ijcpe vol.13 no.4 (december 2012) -available online at: www.iasj.net results and discussion analysis and optimization of experimental results: the response of experimental work conducted according to box-wilson [18], is represented by the removal percentage of nickel ions (r%): r% = (co – cf) / co × 100% …(3) where: co: initial concentration of nickel ions (mg/l). cf: final concentration of nickel ions (mg/l). it is fitted by a second–order polynomial mathematical model. a second order polynomial equation is employed in the range of the independent three variables (x1= temperature, x2= ph and x3 = time) were considered. the general form of a second order polynomial can be represented in the following equation: r%=b0+b1x1+b2x2+b3x3+b4x 2 +b5x 2 2+b6x 2 3+b7x1x2 + b8x1x3 + b9x2x3 …(4) using the real data of central composite design is given in table (2) to determine the coefficients of equation (4) by using statistica software ver. 6. equation (4) can be written as follows: r%=0.45+2.5886x1+18.995x2+ 0.32276x3 -0.0556x1 2 -2.5064x2 2 0.0006x3 2 +0.2833x1x2-0.0142x1x3 0.0882x2x3 …(5) correlation coefficient (r) =0.9684 statistical analysis was made by using the above software according (ttest) and least significant differences (l.s.d) at p-value equal or less than (0.05). table (3) shows that all coefficients of equation (4) were significant. he optimization procedure was applied to equation (5) to find the optimum operating conditions (temperature, ph and time) by: a. differentiating equation (5) for three times once; with respect to x1, x2 and x3. b. setting the resulting equations to zero. fig. 1, schematic diagram of the biosorption unit firas hashim kamar al-hamadani -available online at: www.iasj.net ijcpe vol.13 no.4 (december 2012) 51 c. solving these equations simultaneously to find the optimum values of variables (x1, x2 and x3). d. conducting a second differentiation to test for the sufficient conditions to ascertain that the optimum point is indeed a maximum point. the results of optimization indicate that the optimum conditions are: x1 = 35 o c; x2 = 5; x3 = 10 min the removal percentage of nickel ions was equal to 98.8%. table 2, coded and real variables and removal percentage of nickel ions using central composite routable method table 3, statistical analysis according (t-test) and least significant differences (l.s.d) exp. no. coded variables real variables (r)% x1 x2 x3 x1 x2 x3 1 1 1 1 35.7 6.154 96.75 30.287 2 -1 1 1 24.2 6.154 96.75 33.837 3 1 -1 1 35.7 3.845 96.75 41.209 4 1 1 -1 35.7 6.154 33.24 80.698 5 -1 -1 1 24.2 3.845 96.75 52.632 6 -1 1 -1 24.2 6.154 33.24 74.243 7 1 -1 -1 35.7 3.845 33.24 79.054 8 -1 -1 -1 24.2 3.845 33.24 80.742 9 1.732 0 0 40 5 65 56.750 10 0 1.732 0 30 7 65 49.697 11 0 0 1.732 30 5 120 29.124 12 -1.732 0 0 20 5 65 63.085 13 0 -1.732 0 30 3 65 61.196 14 0 0 -1.732 30 5 10 98.288 15 0 0 0 30 5 65 65.037 16 0 0 0 30 5 65 65.037 17 0 0 0 30 5 65 65.037 18 0 0 0 30 5 65 65.037 variables coef. se t-test p-value constant 0.45 12.60 0.04 0.973 x1 2.5886 0.5247 4.93 0.001 x2 18.995 2.451 7.75 0.000 x3 0.32276 0.07688 4.20 0.003 x1 2 -0.055574 0.007461 -7.45 0.000 x2 2 -2.5064 0.1863 -13.45 0.000 x3 2 -0.0005838 0.0002464 -2.37 0.045 x1 x2 0.28325 0.04903 5.78 0.000 x1 x3 -0.014209 0.001783 -7.97 0.000 x2 x3 -0.088180 0.008878 -9.93 0.000 significance equal or lower than (0.05). (p≤ 0.05) removal of nickel ions using a biosorbent bed (laminaria saccharina) algae 52 ijcpe vol.13 no.4 (december 2012) -available online at: www.iasj.net effect of operating variables on biosorption effect of temperature the variation of removal percentage of nickel ions with temperature of simulated wastewater is shown in fig. (2). it can de concluded that maximum removal percentage of nickel ions has been obtained at (35) o c. this suggests that biossorption between algal biomass and metal could involve a combination of chemical interaction and physical adsorption. with increasing temperature above (20 to 35) o c, pore in the algae enlarge resulting in an increase of the surface area available for the sorption, diffusion, and penetration of nickel ions within the pores of algae causing an increase in sorption [19]. also increasing temperature is known to increase the diffusion rate of adsorbate molecules within pores as a result of decreasing solution viscosity and will also modify the equilibrium capacity of the adsorbent for a particular adsorbate. further increase in temperature (above 35 o c) leads to decrease in the removal percentage. this decrease in biosorption efficiency may be attributed to many reasons: increasing in the relative escaping tendency of the heavy metal from solid phase to the bulk phase, deactivating the biosorbent surface, or destructing some active sites on the biosorbent surface due to bond ruptures [20] or due to the weakness of biosorption forces between the active sites of the sorbents and sorbate species and also between the adjacent molecules of sorbet phase [21]. effect of ph in order to examine the effects of ph on removal efficiency of the nickel ions, several experiments were carried out at various initial values (from 3 to 7) with different times (from 10 to 120 min). the experimental data showed that the optimum ph for removal percentage of nickel ions was (5); this is in good agreement with previous studies [22, 23]. at ph below (3), the positive charge (h + ) density on the sites of biomass surface minimizes metal sorption, and above (5), metal precipitation is favored. fig. (3) shows the effect of ph on the biosorption efficiency of nickel ions at different times. fig. 2, effect of temperature on the removal percentage of nickel ion at different times firas hashim kamar al-hamadani -available online at: www.iasj.net ijcpe vol.13 no.4 (december 2012) 53 effect of time the removal percentage of nickel ions at various temperatures with time is shown in fig. (4). at best ph value of (5), the removal percentage of nickel ions decreased with time up to a maximum value after (10) min to be zero after (120) min, and in the other hand fig. (5) shows that the removal efficiency of the nickel ions was decreased with time from 97.6 % after 10 min to zero after 120 min and this is occurred at best favorite temperature 35 o c. therefore, the effect of the biosorption time is very important because a bed was made by a biosorbent material (algae particles), which it will gradually be saturated with time and lose their ability to absorb nickel ions after 120 min [24]. fig. 3, effect of ph on the removal percentage of nickel ions at different times fig. 4, effect of time on the removal percentage of nickel ions at different temperature removal of nickel ions using a biosorbent bed (laminaria saccharina) algae 54 ijcpe vol.13 no.4 (december 2012) -available online at: www.iasj.net fig. 5, effect of time on the removal percentage of nickel ions at different ph conclusions a bed of biosorbent material (a laminaria saccharina) algae can remove the nickel ions from wastewater in a good efficient. effects of the experimental parameters such as (temperature, ph and time) are very important in the biosorption process. the relationship between the removal percentage and above parameters is shown in equation (5). the highest removal efficiency of nickel ions obtained was (98.8)%, at optimum operating conditions as follows: temperature (35) c⁰, ph value (5) at time (10) min. references 1. nocito f., lancilli c., giacomini b., and sacchi g. a., (2007), "sulfur metabolism and cadmium stress in higher plants", plant stress, global science books, vol. 1, no. 2, pp. 142-156. 2. aslam m., hassan i., malik m., and matin a., (2004), "removal of copper from industrial effluent by adsorption with economical viable material", ejeaf che, vol. 3, no. 2, pp. 658-664. 3. world health organization, (2010), "guidelines for drinking water quality", geneva, (1984). res., vol. 4, no. 2, pp. 281-288. 4. arsalani n., rakh r., ghasemi e., and entezami a., (2009), "removal of ni(ii) from synthetic solutions using new amine-containing resins based on polyacrylonitrile", iranian polymer journal, vol. 18, no. 8, pp. 623-632. 5. aslam m.z., ramzan n., naveed s., and feroze n., (2010), "ni (ii) removal by biosorption using ficus religiosa (peepal) leaves", j. chil. chem. soc., vpl.55, no. 1, pp. 8184. 6. keane m. a., (1998), "the removal of copper and nickel from aqueous solution using y zeolite ion exchangers", colloids surfaces a: physicochem. eng. aspects, vol. 138, pp. 11–20. 7. dermentzis k., davidis a., papadopoulou d., christoforidis a., and ouzounis, k., (2009), "copper removal from industrial wastewaters by means of electrostatic shielding driven electrodeionization", journal of firas hashim kamar al-hamadani -available online at: www.iasj.net ijcpe vol.13 no.4 (december 2012) 55 engineering science and technology review, vol. 2, no. 1, pp. 131-136. 8. rengaraj s., kim y., joo c., choi k., and yi. j., (2004), "batch adsorptive removal of copper ions in aqueous solutions by ion exchange resins: 1200h and irn97h", korean j. chem. eng., vol. 21, no. 1, pp. 187-194, . 9. munoz r., guieysse b., (2006), " algal–bacterial processes for the treatment of hazardous contaminants: a review", water res. 40: 2799–2815. 10. volesky, biosorbent materials, biotechnoi. bioeng symp., 16: 121126. 11. mehta s. k., and gaur j. p., (2005), "use of algae for removing heavy metal ions from wastewater: progress and prospects critical reviews in biotechnology", j. hazard materials, 25 (3) 113 – 152. 12. davis a., volesky b., mucci a., (2003), " a review of the heavy metals biosorption by brown algae", j water res 37:4311-4330. 13. naja g., vanessa m., volesky b., (2010), " biosorption, metal, encyclopedia of industrial biotechnology: bioprocess, biosepration, and cell technology", wiley, new york. 14. davis t., volesky b., mucci a., (2003), "a review of the biochemistry of heavy metal biosorption by brown algae", water research, 37(18), 43114330. 15. sun b. c., yeoung-s. y., (2006), "biosorption of cadmium by various types of dried sludge: anequilibrium study and investigation of mechanisms", journal of hazardous materials b138, 378–383. 16. fourest e., volesky b., (1997), "alginate properties and heavy metal biosorption by lamenarine algae ", appl biochem biotechnology, 67, p. 33-44. 17. sprynskyya m., buszewski b., terzyk a.p., and snik j. n., (2006), "study of the selection mechanism of heavy metal (pb2+, cu2+, ni2+, and cd2+) adsorption on clinoptilolite" , journal of colloid and interface science, vol. 304, pp. 21–28. 18. davis d.l., (1963), "design and analysis of industrial experiments", 2 nd ed., oliver and boyd, london. 19. saleem m., pirzada t., qadeer r., (2007), "sorption of acid violet 17 and direct red 80 dyes on cotton fiber aqueous solution., colloids surf, a physicochem eng. asp 292:246-250. 20. meena ak., mishrr gk., rai pk., rajagopal c., nagar pn., (2005), " removal of heavy metal ions from aqueous solution using carbon aerogel as an adsorbent", j hazard mater, 122:161-170. 21. ahmed s., mustafa t., (2008), " biosorption of cadmium(ӏӏ) from aqueous solution by red algae (ceramium virgatum): equilibrium, kinetic and thermodynamic studies", j hazard mater, 157:448-454. 22. jinbai yang, (1999), "biosorption of uranium and cadmium on sargassum seaweed biomass ph.d. thesis, mcgill university, departement of chemical engineering, canada. 23. romera e., gonzalez f., ballester a., blazquez munoz ja, (2007), "comparative study of heavy metals using different types of algae", j bioresour tech 98:3344-3353. 24. mehta s. k., and j. r., (2002), "use of algae for removing heavy metal ions from wastewater progress prospects, p. 432. iraqi journal of chemical and petroleum engineering vol.16 no.4 (december 2015) 5158 issn: 1997-4884 density, viscosity and refractive index of the ternary system (ethanol + n-hexane +3-methyl pentane) at 20, 30, 40 ° c and 101.325 kpa ghazwan a. mohammed * and maryam kh. oudah * chemical engineering department-college of engineering-university of baghdad-iraq abstract experimental densities, viscosities η, and refractive indices nd data of the ternary ethanol+ n-hexane + 3-methyl pentane system have been determined at temperatures 293.15,303.15 and 313.15 k and at atmospheric pressure then these properties were calculated theoretically by using mixing rules for densities, viscosities and refractive indices .after that the theoretical data and the experimental data were compared due to the high relative errors in viscosities an equation of viscosity was proposed to decrease the relative errors. key words: thermodynamic properties, measuring, viscometer, pycnometer , refractive indices. introduction prediction of the thermodynamic properties of materials associated with the process can greatly affect the design, cost, and in some cases even determine the feasibility of a given unit operation. the need for accurate values of thermodynamic properties of an increasing variety of materials to support the design of processes places a strong emphasis on the development of techniques with predictive capabilities that can be used for a wide range of process conditions and mixtures with limited reliance on experimental data beyond that used at the early stages of the process development [1]. in such regard, thermodynamic and transport properties of fluid mixtures are required that might sometime obtained from tables but it is usually found that even the most extensive physic-chemical tables do not contain all the data necessary for designing a technological process. in such cases, properties have only been studied for pure components from which the mixture is constituted where method is required for estimating the properties of the mixtures. such predictions usually entail large difficulties [2]. finally, properties alone remain elusive; failure to reach this goal as follows from an inadequate fundamental understanding of liquid structure and intermolecular forces. all macroscopic properties are related to molecular structure, which determines the magnitude and predominant type of the intermolecular forces [3]. iraqi journal of chemical and petroleum engineering university of baghdad college of engineering density, viscosity and refractive index of the ternary system (ethanol + n-hexane +3-methyl pentane) at 20, 30, 40 ° c and 101.325 kpa 52 ijcpe vol.16 no.4 (dec. 2015) -available online at: www.iasj.net experimental section 1materials ethanol, n-hexane and 3-methyl pentane were used in preparing the binary and ternary systems studied and acetone was used for cleaning the glassware were all purchased from sigma and thomas baker with purity over 99%. table 1 lists values of the properties of chemicals used in this study given by literature [4]. table 1, densities (ρ), viscosities (η), and refractive indices (nd) of pure compounds used in this work compared with literature data at t = 20 o c, t = 30 o c and 40 o c at atmospheric pressure t = 20 o c compound ⍴ / g.cm -3 η /mpa.s nd exp. lit. exp. lit exp. lit. ethanol 0.7895 0.790(75) 1.247 1.184(79) 1.3618 1.3618(79) n-hexane 0.6480 0.655(34) 0.364 0.301(27) 1.3718 (98) 1.376 3-methyl pentane 0.659 0.6537(15) 0.301 0.292(41) 1.376 1.376(98) t = 30 o c ethanol 0.7702 0.7709(76) 1.1514 0.997(79) 1.3600 -- n-hexane 0.64078 0.651(15) 0.3280 0.2956(79) 1.3730 -- 3-methyl pentane 0.659 0.65369(15) 0.2674 0.263796(41) 1.3714 -- t = 40 o c ethanol 0.7614 0.7728(76) 0.8742 0.793(76) 1.3574 -- n-hexane 0.63118 0.6411(77) 0.29681 0.2537(79) 1.3695 -- 3-methyl pentane 0.6435 0.6440(15) 0.2357 0.2398(41) 1.3689 -- 2measurements densitie ρ measurements were measured, by pycnometer, while viscosity and refractive index measurements were made by using the cannon-fenske routine viscometer and refractometer respectively. results and discussion 1density the densities of the pure components ethanol and n-hexane were calculated using equations (1) and (4) respectively, while the density of pure water was determined by using equation (5). as for the density of pure component 3-methyl pentane equation (9) was used. ⍴ ⍴ ⍴ * ( ) ( ) + ... (1) po = 0.1013 mpa where : ρo = ρ c {1 + ∑ (1-tr) (i/3) } ... (2) and = 331.2083 713.86 tr + 401.61 tr2 – f ... (3) for ethanol: = 520.23 -1240 tr + 827 tr 2 – f ... (4) ghazwan a. mohammed and maryam kh. oudah -available online at: www.iasj.net ijcpe vol.16 no.4 (dec. 2015) 53 for water: ⍴ = 999.84 + 0.053 (t273.15) – 7.315*10 -3 (t-273.15) 2 +3.03*10 -5 (t-273.15) 3 ... (5) for 3-methyl pentane using equation (6): = vr (0) [ 1 wsrk vr (δ) ] ... (6) where: vr (0) = 1+ a [1tr] (1/3) + b (1-tr) (2/3) + c (1-tr) + d (1-tr) (4/3) ... (7) 0.25 < tr < 0.95 and vr (δ) = ( – ) ... (8) 0.25 < tr < 1.00 for, tc obtained from table 2. table 2, pure component parameters for the hankinson-brobstthomson and the rackett liquid volume correlations 3-methyl pentane v* (l /mol) wsrk pc (bar) tc (k) 0.3633 0.2741 31.2 504.34 the values of the constants in equations above are: a = -1.52816 , b =1. 43907, c = 0.81446 , d = 0.190454 e = -0.296123 , f = 0.386914, g = 0.0427258, h = 0.0480645. as listed in table 2 v* is a pure component characteristic volume generally within 1 to 4 percent of the critical volume, wsrk is the acentric factor which forces the soave equation to give a best fit, of existing vapor pressure data. values of v* and wsrk are given in table 2 [ 5, 6 , 7 ].thomson et all have extended the hbt method to allow prediction by generalizing the constants in the tait equation [ 7 ], thus : v = vs (1c ln ) ... (9) where vs is defined as the saturated liquid volume at the vapor pressure pvp , which obtained from equation (6). the rest of the parameters , and c are obtained from as illustrated below in equations 10, 11, 12 and 13: / pc = -1 + a (1tr) (1/3) + b (1 tr) (2/3) + d (1tr) + e (1tr) (4/3) ... (10) where [3] ln ( /pc) = (1-x) -1 [(vpa) x + (vpb) x 1.5 + (vpc) x 3 + (vpd) x 6 ] ... (11) x = 1 ... (12) values of vpa, vpb, vpc and vpd are given in table 3. table 3, vapor pressure, in bars 3-methyl pentane vpd vpc vpb vpa -2.17642 -2.81741 1.26113 -7.27084 e = exp (f + g wsrk + h w 2 srk) … (13) and c = j + k wsrk ... (14) a = 9.070217 , b = 62.45326, d = -135.1102 , f = 4.79594, g = 0.250047 , h = 1.14188, j = 0.0861488 , k = 0.034483 density, viscosity and refractive index of the ternary system (ethanol + n-hexane +3-methyl pentane) at 20, 30, 40 ° c and 101.325 kpa 54 ijcpe vol.16 no.4 (dec. 2015) -available online at: www.iasj.net equation (15) applied to ternary system to calculate the density for the ternary system (ethanol +n-hexane +3methyl pentane): ⍴mix = w1 * ⍴1 + w2* ⍴2 + w3* ⍴3... (15) where ⍴1, ⍴2, ⍴3 were the densities of pure component 1, 2, 3 and w1, w2 , w3 were the weight fractions of component 1,2,3. ( ( ) ) ... (16) the density of the ternary system ethanol (1) + n-hexane (2) + 3-methyl pentane (3) was calculated using the pure density of each component and the weight fraction and equation 15. the results were compared with experimental values by calculating the % relative error (%er) given by equation 16. table 4 lists the results of the comparison at 20 o c while table 5 and 6 lists values at 30 o c and 40 o c respectively. table 4, density (⍴) of ternary system, ethanol (1) + n-hexane (2) + 3-methyl pentane (3) at different weight fractions of ethanol (wt.1) at temperatures 20℃ %er ⍴ equ. (15) ⍴ exp. wt.2 wt.1 1.10 1.50 1.62 1.61 2.07 2.04 2.19 2.06 0.28 1.61 0.6552 0.6743 0.6771 0.6810 0.7045 0.7175 0.7271 0.7483 0.7873 average 0.6480 0.6643 0.6663 0.6702 0.6902 0.7031 0.7116 0.7331 0.7895 0.950 0.813 0.793 0.765 0.595 0.502 0.433 0.281 0.000 0.00000.1 45 0.166 0.195 0.374 0.472 0.545 0.705 1.000 table 5, density (⍴) of ternary system, ethanol (1) + n-hexane (2) + 3-methyl pentane (3) at different weight fractions of ethanol (wt.1) at temperatures 30℃ %er ⍴ equ.(15) ⍴ exp. wt .2 wt .1 0.84 1.74 1.67 2.12 2.85 2.08 1.91 1.37 1.10 1.63 0.6461 0.6653 0.7200 0.6956 0.7086 0.7183 0.7395 0.7571 0.7787 average 0.6408 0.6539 0.6610 0.6812 0.6890 0.7037 0.7257 0.7543 0.7702 0.950 0.813 0.765 0.595 0.502 0.433 0.281 0.155 0.000 0.000 0.145 0.195 0.374 0.472 0.545 0.705 0.837 1.000 table 6, density (⍴) of ternary system, ethanol (1) + n-hexane (2) + 3-methyl pentane (3) at different weight fractions of ethanol (wt.1) at temperatures 40℃ %er ⍴ equ. (15) ⍴ exp. wt.2 wt.1 0.92 2.01 2.11 2.53 2.50 2.30 2.12 1.13 1.95 0.6370 0.6561 0.6651 0.6892 0.7016 0.7097 0.735 0.7700 average 0.6312 0.6431 0.6514 0.6722 0.6846 0.6937 0.7163 0.7614 0.950 0.813 0.749 0.577 0.488 0.431 0.275 0.000 0.000 0.144 0.212 0.393 0.486 0.547 0.711 1.000 2viscosity the viscosity values for the pure components and the ternary system was measured. the viscosity of pure components ethanol and n-hexane was calculated from equation (17) while viscosity of water was calculated by using equation (18), and finally the viscosity for 3-methyl pentane was determined by using equation (19). η* = ( ) (2 na) (1/3) π (1/2) ( ) (1/2) ( η ( ) ) ... (17) ln η =a +b/t +c* t +d*t 2 ... (18) ln ... (19) ghazwan a. mohammed and maryam kh. oudah -available online at: www.iasj.net ijcpe vol.16 no.4 (dec. 2015) 55 where ηl=liquid viscosity, in cpand ⍴l is the iquid density at 20 c in g/cm 3 . m is the molecular weight in g/mole and t is the temperature in k and the constants a and b are given in table 7 [ 8 ]. table 7, the parameters of orrick and erbar method 3-methyl pentane b a 275+ 99n -(6.95 + 0.21n) 35 -0.15 when n = the carbon number. fig. 1, the data given in tables 6, 7 and 8 are plotted as viscosity verses weight fraction at temperatures t = 20 o c , 30 o c and 40 o c figure (1) shows the experimental values of viscosity as plotted versus weight fraction of ethanol for ternary system it was noted the increase in the value of viscosity as weight fraction of ethanol increases in such respond, we proposed an equation that involves the use of activity coefficients as shown in equation (20) for determination of viscosity values in ternary system. η = a* ηmix * ( ) b ... (20) ηmix is defined by equation (21),and ϓ1 and ϓ2 known as activity coefficients of component 1 and 2 determined from wilson model. while a, ηmix and b are determined from following equations. ηmix = w1 * η1 + w2* η2 + w3* η3... (21) a= (ρ ρ ) (ρ ρ ) ... (22) b= ( ) ... (23) where ρc is the critical density of a component. when equation (20) was applied on the above ternary system the relative errors have been reduced as noticed in tables 8, 9 and 10. table 8, viscosities (η) of the ternary system ethanol (1) + n-hexane (2) + 3-methyl pentane (3) at different weight fractions of ethanol (wt.1) at temperature of 20 o c determined using equation (20). er% η exp. η equ 20 ϓ2 ϓ1 wt.2 wt.1 25.48 8.92 9.49 2.69 5.34 2.65 2.04 14.86 5.19 0.3645 0.4285 0.4497 0.4423 0.6039 0.6328 0.6938 1.2473 average 0.2716 0.3903 0.4070 0.4304 0.5717 0.6496 0.7079 1.0747 1.000 1.231 1.278 1.346 1.851 2.203 2.506 5.584 19.428 2.648 2.387 2.114 1.379 1.221 1.146 1.000 0.950 0.813 0.793 0.765 0.595 0.502 0.433 0.000 0.000 0.144 0.166 0.195 0.373 0.471 0.545 1.000 0 0.2 0.4 0.6 0.8 1 1.2 1.4 0 0.2 0.4 0.6 0.8 1 e x p e ri m e n ta l v is co si ty ( cp ) weight fraction of ethanol (1) t = 20c t = 30c t = 40c density, viscosity and refractive index of the ternary system (ethanol + n-hexane +3-methyl pentane) at 20, 30, 40 ° c and 101.325 kpa 56 ijcpe vol.16 no.4 (dec. 2015) -available online at: www.iasj.net table 9, viscosities (η) of the ternary system ethano (1) + n-hexane (2) + 3-methyl pentane (3) at different weight fractions of ethanol (wt.1) at temperature of 30 o c determined using equation (20). er% η exp. η equ 20)) ϓ2 ϓ1 wt.2 wt.1 26.90 4.41 1.62 8.66 6.28 7.48 3.33 6.87 14.48 5.57 0.328 0.363 0.377 0.468 0.544 0.586 0.722 0.904 1.151 average 0.239 0.347 0.383 0.509 0.578 0.630 0.746 0.842 0.963 1.000 1.270 1.400 1.996 2.447 2.866 4.143 5.808 9.322 40.38 3.078 2.411 1.502 1.302 1.205 1.075 1.022 1.000 0.950 0.813 0.765 0.595 0.502 0.433 0.281 0.155 0.000 0.000 0.145 0.195 0.374 0,472 0.545 0.705 0.837 1.000 table 10, viscosities (η) of the ternary system ethanol (1) + n-hexane (2) + 3-methyl pentane (3) at different weight fractions of ethanol (wt.1) at temperature of 40 o c determined using equation (20). er% η exp. η equ 20 ϓ2 ϓ1 wt.2 wt.1 23.82 4.68 0.84 6.72 2.69 0.42 0.84 14.48 2.70 0.2968 0.3208 0.3434 0.4055 0.4682 0.5140 0.6022 0.8742 average 0.2261 0.3058 0.3405 0.4328 0.4808 0.5119 0.5972 0.7515 1.000 1.261 1.437 2.061 2.506 2.854 4.158 9.149 35.553 3.078 2.254 1.451 1.277 1.201 1.071 1.000 0.950 0.813 0.749 0.577 0.488 0.431 0.275 0.000 0.000 0.144 0.212 0.393 0.486 0.547 0.711 1.000 3refractive index the refractive index of the ternary system ethanol (1) + n-hexane (2) + 3methyl pentane (3) was calculated from pure component data by using equation (23) and using the volume fraction via equation (24). nd = [ 1 + φ1 ( nd1 2 – 1) + φ2 ( nd2 2 – 1) + φ3 ( nd3 2 – 1)] (1/2) … (23) φi= ... (24) it seemed as pointed out in table 1 the experimental data of pure compounds obtained in the present study are in good agreement with their corresponding literature values. tables 11, 12 and 13 lists the refractive index of the ternary system determined from above equation and compared with experimental values at 20 0 c, 30 0 c, 40 0 c. ghazwan a. mohammed and maryam kh. oudah -available online at: www.iasj.net ijcpe vol.16 no.4 (dec. 2015) 57 table 11, refractive indices (nd) of the ternary system ethanol (1) + n-hexane (2) + 3methyl pentane (3) at different weight fractions of ethanol (wt.1) and at 20℃ by using equation (23) er % nd exp. nd mix. φ 2 φ 1 wt.2 wt.1 0.031 0032 0.026 0.037 0.034 0.026 0.000 0.027 1.3725 1.3720 1.3718 1.3702 1.3682 1.3658 1.3600 average 1.3729 1.3724 1.3721 1.3707 1.3686 1.3661 1.3600 0.950 0.834 0.792 0.636 0.476 0.317 0.000 0.000 0.125 0.171 0.337 0.506 0.672 1.000 0.950 0.813 0.765 0.595 0.433 0.281 0.000 0.000 0.145 0.195 0.374 0.545 0.705 1.000 table 12, refractive indices (nd) of the ternary system ethanol (1) + n-hexane (2) + 3methyl pentane (3) at different weight fractions of ethanol (wt.1) and at 30℃ by using equation (23) er % nd exp. nd mix. φ 3 φ 2 φ 1 wt.2 wt.1 0.015 0.048 0.076 0.025 0.097 0.034 0.027 0.000 0.04 1.3718 1.3715 1.3710 1.3708 1.3690 1.3670 1.3650 1.3618 average 1.3720 1.3722 1.3720 1.3711 1.3703 1.3675 1.3654 1.3618 0.000 0.044 0.041 0.033 0.028 0.017 0.010 0.000 0.950 0.838 0.782 0.624 0.537 0.315 0.187 0.000 0.000 0.123 0.183 0.352 0.444 0.675 0.808 1.000 0.950 0.813 0.749 0.577 0.488 0.275 0.159 0.000 0.000 0.144 0.212 0.393 0.486 0.711 0.832 1.000 table 13, refractive indexes (nd) of the ternary system ethanol (1) + n-hexane (2) + 3-methyl pentane (3) at different weight fractions of ethanol (wt.1) and at 40℃ by using equation (23) er % nd exp. nd mix. φ 2 φ 1 wt.2 wt.1 0.034 0.049 0.061 0.037 0.053 0.027 0.047 0.000 0.038 1.3690 1.3687 1.3683 1.3674 1.3662 1.3658 1.3630 1.3574 average 1.3695 1.3694 1.3691 1.3679 1.3669 1.3662 1.3636 1.3574 0.950 0.838 0.782 0.624 0.537 0.479 0.315 0.000 0.000 0.123 0.183 0.352 0.444 0.504 0.675 1.000 0.950 0.814 0.749 0.577 0.488 0.431 0.275 0.000 0.000 0.144 0.212 0.393 0.486 0.547 0.711 1.000 density, viscosity and refractive index of the ternary system (ethanol + n-hexane +3-methyl pentane) at 20, 30, 40 ° c and 101.325 kpa 58 ijcpe vol.16 no.4 (dec. 2015) -available online at: www.iasj.net conclusion the collected experimental data for the densities and the refractive indices of the ternary system are in good agreement with the theoretical data. because of close matching between experimental and theoretical data we found there is no need to propose new correlation for the determination of density and refractive index for predicting ternary system from pure component data. while for the viscosities of the binary and ternary systems, the relative errors were high so a new correlation was. the new proposal gave good results and could be suitable for liquid solutions. nomenclature %er: relative error ⍴: density at t and p ⍴ : density at to and po ⍴c: density at tc and pc abs: absolute value ai: constant in equation 2[9] b: pressure correction in equation 3: f: constant in equation 3 na: avogadros constant nd: refractive index of mixture ndi: refractive index of component i pc: critical pressure po: reference pressure pve: vapor pressure r: universal gas constant t: temprature tc: critical temperature tr: reduced temprature v: volume vm: molar volume vr(0): reduced volume defined by equation 7 vr(δ): reduced volume defined by equation 8 vs: volume at saturation wi: weight fraction of component i wsrk: acentric factor z: coordination number[9] : pressure term in equation 10 η: viscosity ηmix: viscosity of mixture π: pi ρmix: density of mixture ϓi: activity coefficient of component i references 1dohrn, r.; pfohl, o. thermophysical properties – industrial directions. fluid phase equilib. 2002, 194−197, 15−29. 2giro, f. ;goncalves, m. f.; ferreira, a. g. m. and fonseca, i. m. a.,(2003), " viscosity and density data of the system water + npentyl acetate+methanol, calculations with a modified redlich-kwong-soave equation of state" fluid phase equilibria , (204): 217-232 . 3reid, r. c. ; prausnitz, j. m. and poling, b. e. ,(1987), "the properties of gases & liquids" 4th ed. ,mcgraw – hill. 4oudah, m. f and mohammed, g. a “prediction of thermodynamic properties of ternary system from pure component data”. m.sc. thesis college of engineering, baghdad university 2015. 5hankinson, r. w. and thomson, g. h. ,(1979), " american institute of chemical engineers journal", (25):653. 6guevara, m. f. and rodriguez, a. t. ,(1984), "journal of chemical & engineering data", (29):204. 7spencer, c. f. and danner, r. p. ,(1972), "journal of chemical & engineering data", (17):236. 8bretsznajder, s. and danckwerts, p. v. ,(1971)," prediction of transport and other physical properties of fluids " , pergamon press, oxford. 9marc j. assael, j. p. martin trusler and thomas f. tso akis, (1996),” thermophysical properties of fluids an introduction to their properties”, imperial college press, london. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol. 24 no.1 (march 2023) 113 – 124 eissn: 2618-0707, pissn: 1997-4884 *corresponding author: name: ali khaleel faraj, email: ali.faraj2008m@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. application of finite element technique: a review study ali khaleel faraj a, b, * and hassan abdul hadi abdul hussein a a petroleum engineering department, college of engineering, university of baghdad, iraq b petroleum technology department, university of technology, iraq abstract the finite element approach is used to solve a variety of difficulties, including well bore stability, fluid flow production and injection wells, mechanical issues and others. geomechanics is a term that includes a number of important aspects in the petroleum industry, such as studying the changes that can be occur in oil reservoirs and geological structures, and providing a picture of oil well stability during drilling. the current review study concerned about the advancements in the application of the finite element method (fem) in the geomechanical field over a course of century. firstly, the study presented the early advancements of this method by development the structural framework of stress, make numerical computer solution for 2d thermal stress then stress analysis of the airplane. the second part focused on the most recent developments of fem, and this method generates new techniques for solving these problems, such as the 1d, 2d, and 3d finite element models; the dynamic program method (dpm); the finite discrete element method (fdem); and the finite element extended method (fexm). the third part of this study presented the reservoir finite element simulation used for injection well testing inside unconsolidated oil sand reservoirs. also improvement of the fe software program for the analyses, finite element extended approach to convert a 3d fault model were introduced. in addition, the study explored the development of a 3d and 4d model utilizing visage for fem analysis for geomechanics investigations, and the software eclipse for pressure drop prediction in carbonate reservoir weak formation and presented the finite-element smoothed particle method (fespm). keywords: finite element method, geomechanical model, finite discrete element method, dynamic program model. received on 11/06/2022, received in revised form on 17/08/2022, accepted on 23/08/2022, published on 30/03/2023 https://doi.org/10.31699/ijcpe.2023.1.13 1introduction geomechanics is a branch of science that studies the relationship between geology and rock mechanical properties. in other words, it is concerned with the effects of stress on distort or failure of rocks caused by changes in stress direction, abnormal pressure, temperature, and fluid flow caused by production. wellbore instability is one of the most complicated problems that can occur during the drilling process, increasing nonproductive time. as a result, the cost of drilling will rise, and geomechanical analysis will be required to reduce this high cost [1]. areas with strong topographic pressure, such as shale layers, can lead to wellbore instability [2]. a numerical method, such as finite element methods (fem), is required to solve this deformation. the term "finite element measurement" refers to a numerical model that can be used to identify problems and find solutions in several fields of study. grid deformation, temperature change, phase flow, and magnetic current power are some of the most common locations of interest that are solved using the finite element method. while the problems that could be solved using this method included a complex geomechanical model, the distribution of stress, and subsidence issues caused by pressure depletion in the reservoir rock, analysis type solutions were not allowed for these problems because the values at any point in the reservoir structure measurement using math terms were unknown [3]. to obtain a satisfactory solution for the issues mentioned, the fem relied on a numerical calculation; this method will convert these issues into an arrangement stimulation algebraic formula, rather than using the differential formulation [3]. 2early development of fem in the 1940s, alexander paul hrennikoff developed the field structural framework method for stress analysis and its application to two fields of elasticity, which is essentially an arithmetic procedure that can be applied to any problem involving a rectangular plate by the twodimensional stress and strain situation in a bent plate. the most important aspect of the framework method is that it may be used to solve a wide range of insoluble elastic problems. this method is credited with laying the groundwork for the finite element method [4]. douglas mchenry presented in 1943 a numerical computer solution for practically all problems involving 2d thermal stress, including material in the elastic area; this element is about sequential approximation, in which the rigor of the output was entirely determined by the amount of work done. the computer's resourcefulness in utilizing such expedient for solving those difficulties will play a key role in the method's successful practical use [5]. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:ali.faraj2008m@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2023.1.13 a. k. faraj and h. a. abdul hussein / iraqi journal of chemical and petroleum engineering 24,1 (2023) 113 124 114 in 1947, levy enhanced the pliability or force approach using castigliano's theory, as well as a stress analysis of the airplane construction based primarily on equilibrium conditions [6]. following that, in 1953, he proposed a new computation termed the (stiffness method) as an alternative for determining stress and deformation in statistical analyses for aircraft structures. poisson's ratio's function in creating anticlastic curvature has also been overlooked, despite the fact that the equations he creates are too difficult to answer by hand. when the poisson ratio is ignored, a mistake could be made [7]. turner et al. (1956) were the first to handle 2d elements. they were derived from the stiffness matrix for elements, as well as 2d triple and perpendicular finite elements for the stress effect into the plane, and these proceedings were summed up as the hardness method for determining the overall matrix for hardness structure. by incorporating improvements to the digit program into the turner's job, the speed of the software can be increased. programs for performing such computations can be developed using the basic concepts provided in this study [8]. gallagher began working on 3d problems in triangular and rectangular shapes in 1962, developing a complicated structure analysis approach for heating and elastically stress and strain deformation in structural components as show in fig. 1 below. the accuracy of the data acquired thus far has been called into doubt. this can be improved by using rectangular pieces and just using tetrahedrons to denote irregular borders [9]. fig. 1. total strain vs temperature [9] by studying the matrix discrete-element stiffness to formulation of the linear system issues in mechanics of the engineering, archer improved a strategy that may give proper or almost approximate solving for static stressdisplacement, elastic constancy, and dynamic response problems in 1965. the techniques discussed for using the discrete-element impact method to handle the public static load, elastic stability, and deformation problems provide a considerable improvement in the capacity of this approach to provide accurate numerical solutions for the general analysis of structures [10]. in 1968, zienkiewicz et al. presented the visco-elastic approach for stress and strain analysis, which involved employing models linked to a series and keeping a running total of strain for analysis with fixed or changing temperature properties, the fact that this formulation is a computer model that can be applied to deep well [11]. in 1970, zienkiewicz and parekh subediting in expression a finite element operation using curved and program for both 3d and 2d, isoparametric elements were a method that applied by using the time-step resolution, and their utility was explained through a number of transient field problems dealing with heat conduction problems. the twodimensional software includes simple triangle as well as curved features. the three-dimensional software contains linear, parabolic, and cubic hexahedra based on elements. it will be seen that predefined boundary inflows are comparable to external loads and that the thermal transfer coefficient functions as an external stiffness associated with boundaries [12]. ted belytschko demonstrated a computational mechanism for overcoming difficulties related to largedisplacement nonlinear dynamics for nuclear power reactors in 1976. time integration methods are classified into two types: explicit and implicit. the time step must be small enough. this is the only limitation of these approaches. a wide range of reactor safety concerns can be addressed using the applications offered [13]. lyness et al in 1977 applied the technique of the weighted residuals for measurement the magnetic field of the threedimensional problem in heterogeneous source in expression of the unknown potential porosity and a known analytical solution. the scalar potential appears to be the most efficient approach for the analysis of nonhomogeneous three-dimensional issues, and it is expected that finite element and integral approaches will be merged in the future for practical work [14]. table 1 listed a summary of early development. 3recent advances improvements to the finite element method and its applications in geomechanical studies were first seen in 1995, when jin-zhang et al. demonstrated these native techniques for measuring shear strength in a curve while referring to the position of critical slip surface potential and the dynamic programming method (dpm) was improved. the results were obtained using a finite method-dpm for a curve that was in a state known as homogenous, and a typical finite element mechanism was used as a comparison approach to examine the bridge in flexible clay. the fem– improved dynamic program method (dpm) does have the benefit of over-limit equilibrium methods in that it can represent the strain behavior of soil as well as the slope's stage development [15]. to estimate the change in the rock structure caused by pressure depletion in 2003, wan et al. used a number of linked geomechanical models for reservoir fluid flow. these models will have employed a stabilized finite element technique to provide a solution for stress balancing and the equation of pressure. this approach can cause pressure oscillations in low-permeability zones or at very early stages [16]. in the same year, onate and rojek introduced the integration of two methods: element discrete method (edm) blending with finite element method (fem), which means that any geomechanical a. k. faraj and h. a. abdul hussein / iraqi journal of chemical and petroleum engineering 24,1 (2023) 113 124 115 problems in a dynamic reservoir can be analyzed. integration of those methods can be used for spherical 2d, also known as cylindrical 2d, the discretizing by immobile elements and the fem can deal with the solid zoning. this enables us to apply the proposed formulation to situations involving substantial plastic deformation in the domain's continuum. equipment in stonecutting operations can be modeled using the discrete formulation [17]. table 1. summary of early development no author name of study objective year 1 alexander paul hrennikoff. plane stress and bending of plates by method of articulated framework. development framework method of stress analysis . 1940 2 douglas mchen. lattice analogy for the solution of stress problem. calculation numeral solution of nearly kind having troubles of 2d stress . 1943 3 samuel levy. computation of influence coefficients for aircraft structures with discontinuities and sweepback. show coefficients was outlined which uses castigliano's theorem, together with a stress analysis of the airplane structure. 1947 4 samuel levy. structural analysis and influence coefficients for delta wings. method is show for measurement the stresses and deformations in delta wings. 1953 5 turner, clough, martin, and topp. stiffness and deflection analysis of complex structures. method is developed for determined stiffness influence coefficients of complex shell-type structures. 1956 6 richard h. gallagher, joseph padlog and p. p. bijlaard. stress analysis of heated complex shapes. new relationships are proposed for the analysis of solids. 1962 7 john s. archer. consistent matrix formulations for structural analysis using finite-element techniques. make a dynamic analysis by improved a technique that may be give correct or nearly approximate solving for static stress displacement, elastic constancy, and dynamic problem. 1965 8 zienkiewicz, o. c., m. watson, and i. p. king. numerical method of visco-elastic stress analysis introduced a vlsco-elastie method for stress and strain by using a models linked with a series and through keep a running total of strain. 1968 9 zienkiewicz, o. c., and c.j. parekh. transient field problems: two‐ dimensional and three‐dimensional analysis by isoparametric finite elements. introduced finite element operation utilize program of curved for both 3d and 2d by using the time step resolution. 1970 10 belytschko, ted. survey of numerical methods and computer programs for dynamic structural analysis. show a numerical mechanism for resolving problems that associated with large-displacement nonlinear dynamic. 1976 11 zienkievicz , lyness and d.r owen three-dimensional magnetic field determination using a scalar potentiala finite element solution. applied the technique of the weighted residuals for measurement in threedimensional problem. 1977 in 2004, hammah et. al. introduced a stability analysis for the rock using the finite element method and examined the finite element techniques (fet) analysis for the measurement of rock safety factors for which strength is modeled by the widely used hoek-brown failure criterion, the shear strength reduction (ssr) first outcomes will be used as a standard mechanism for fes slope of mohr-coulomb criteria. however, it might be able to include the ssr approach for general hoek-brown strength automatically into a fe computational engine, as there will be no necessity for explicitly determining factored general hoek-brown parameters in this case [18]. by combining an element agreement into another reservoir commercial stimulation, liu and han (2004) demonstrated finite element and finite different methods for stress distribution with a reservoir fluid model, resulting in a 3-d difference in elastic stress solving with fluid flow and pressure prediction. on larger situations, the results reveal that the accuracy of solving finite difference stress calculations is no better than finite element. it looks into using an iterative technique to produce a more fully connected solution for finite element stress estimation and reservoir simulation fluid flow [19]. when wong used galerkin's least square (gls) mechanism to discretize the saturation equation in 2005, the finite element approach was continuous development in terms of the geomechanics-thermal reservoir simulator. the data show how the vertical displacements at the surface of the formation have altered through time as show in fig. 2. due to heat transmission and fluid flow, the surface heaves to a maximum value of strain [20]. fig. 2. surface displacement results at different time [20] a. k. faraj and h. a. abdul hussein / iraqi journal of chemical and petroleum engineering 24,1 (2023) 113 124 116 jha and juanes (2006) also show a simulation framework calculation to the fluid flow with the geomechanics of reservoirs, where the theory of biot's for fluid flow in single phase regime with linear poroelasticity was the physical mean of this model, where the unknown variables are the pressure, fluid velocity, and rock displacement, and the unknown variables are space with time discretization of these equations. this study focused solely on single-phase linear poroelasticity. clearly, this is insufficient for simulating and predicting many geomechanical processes in reservoirs and nearwells [21]. another advancement for fim occurred in 2008, when maria tchonkova et al. developed new porelasticity numerical solutions using mixed finite element formulated a new equation with four unknown classifications (change in space, stress, formation pressure, and speed) that were tested on 2d and 1d classic porelasticity problems. this research can also be viewed as a hybrid least-squares approach stabilization strategy. more test functions can be applied to stabilize the chosen regions of displacements and stresses (pressures and velocities) if they are still not consistent [22]. in 2009, brice lecampion introduced a new finite element extended technique (fexm) for handling hydraulic fracture issues that took into consideration the presence of an internal pressure within the crack. the findings demonstrate how critical it is to compensate for the loss of division of unity inside the transition region between the enriched and the rest of a mesh. to get accurate results, a point-by-point matching approach appears to suffice. for good performance, a connection of the single addition to expressing by enrichment functions is often required [23]. in 2012, mahabadi et. al. presented a new combined code element method called y-geo fde or finite discrete element method (fdem) for the application of geomechanical studies. which was a design by innovative thinkers that used numerical technology to integrate the characteristics of continuous-model approaches with the method of dem to overcome the disability of those methods to catch the cumulative damage with the failure that may occur in the rocks as show in fig. 3 below [24]. hamed et al. (2016) utilized the finite element method and the sicma/w program to analyze the stress and displacement distribution around a tunnel that was open to the sea in baghdad [25]. table 2 show a summary of recent advances. 4reservoir finite element techniques the reservoir model typically does not account for changes in stress during production or injection, so a finite element method was designed to connect the two models. in 2013, bin xu and wong demonstrated the importance of enhanced oil recovery when they used finite-element simulation for injection well testing inside unconsolidated oil sand reservoirs. well tests such as transit bottom hole pressure data will allow us to determine reservoir flow properties, and the 3d element model is applied to history match the bottom hole pressure replay determined from oil sand zones by using injection wells. plastic shearing and geometric deformations, rather than hydraulic fracture, are prevalent at the water injection rate used in this research [26]. wang et.al. (2013) developed a large finite element method (lfem) approach to expression meshing and interpolation mechanism (mimss) for soil rock in both dynamic and static states. where this mechanism was introduced to the development calculation ability during the moving of the boundary conditions for both dynamic and static analyses. the results illustrate the utility of this technique in geomechanics for dealing with dynamic massive deformation situations. it creates a link that allows traditional geotechnical continuum finite element techniques to be applied to issues that were previously the domain of fluid mechanics [27]. morillo et al. discussed the improvement of the fe software program for the analyses, building model, and stimulation calculation by connecting the fluid model and geomechanical model in 2014. the standard conditions were assumed to be homogeneity and isotropy in the rock, as well as the elastic action on the rock formation with little deformation, a nearly static balance, and the fracture. vertical displacements reveal that the presented profiles from the software and those from the listed authors are quite similar as shown in fig. 4 below, indicating that the program generally functions correctly with gravity activated. the spatial discretization generates a timedependent differential equation that can be solved using the finite difference method [28]. fig. 3. rock failure for two model as follows: (a) homogeneous model, (b) blocky model [24] fig. 4. vertical displacement of the sample, compared with the zheng et al solution, time intervals of 1 minute, and 10 minutes [28] a. k. faraj and h. a. abdul hussein / iraqi journal of chemical and petroleum engineering 24,1 (2023) 113 124 117 table 2. summary of recent advances no author name of study objective year 1 zou, jin-zhang, david j. williams, and wen-lin xiong. search for critical slip surfaces based on finite element method. measurements the local shear strength using finite element method 1995 2 wan, j., l. j. durlofsky, t. j. r. hughes, and k. aziz. stabilized finite element methods for coupled geomechanics reservoir flow simulations. uses a number of coupled geomechanical models for reservoir fluid flow to determine the change happened in the rock structural. 2003 3 onate, e., and j. rojek. combination of discrete element and finite element methods for dynamic analysis of geomechanics problems. show combination of discrete element method (dem) and finite element method (fem) for dynamic analysis of geomechanics problems. 2003 4 hammah, reginald e., john h. curran, t. e. yacoub, and brent corkum. stability analysis of rock slopes using the finite element method. stability analysis for the rock using the finite element method and checked the application of finite element techniques. 2004 5 liu, q., t. stone, g. han, r. marsden, and g. shaw. coupled stress and fluid flow using a finite element method in a commercial reservoir simulator. showing a method for stress and reservoir fluid flow utilized an fem in a communal reservoir software. 2004 6 du, j., and r. c. k. wong. development of a coupled geomechanicsthermal reservoir simulator using finite element method. show a discussion on the development of a coupled geomechanics-thermal reservoir simulator using finite element method (fem). 2005 7 juanes, ruben, and birendra jha. a locally conservative finite element framework for the simulation of coupled flow and reservoir geomechanics. show a simulation calculation formula to reservoir fluid flow and geomechanics.. 2006 8 tchonkova, maria,john peters, and stein sture. a new mixed finite element method for poro-elasticity. new development for the pore-elasticity numerical solutions by mixed the finite element formulated. 2008 9 lecampion, brice. an extended finite element method for hydraulic fracture problems. new finite element extended method was introduced by for the solving of hydraulic fracture problems. 2009 10 mahabadi, omid k., a. lisjak, a. munjiza, and gjijog grasselli. new combined finite-discrete element numerical code for geomechanical applications. new combined code element method for application of the geomechanical studies . 2012 11 abdullah, hamed h., ameer h. al-saffar, and raed s. jasim stresses and displacements analyses around tunnel opening under water body using finite element method (fem) in baghdad city/middle of iraq. utilized the finite element method and the sicma/w program to analyze the stress and displacement distribution. 2016 in several oil and gas fields, rock mechanical properties and analysis of in-situ stress and pore pressure are very important to study and understand the deformation that may be occurring inside the formation. in 2015, kumar and rima demonstrated that these rock properties can be determined using fem and that the three major stresses can be predicted using a 2d stress model as shown above in fig. 5. there is vertical stress (sv) gradients in the range of 21.00 to 22.85 mpa/km. within typically pressured to over-pressured sediments, minimum horizontal principal stress (sh) magnitudes range from 64 percent to 76 percent of sv, whereas maximum horizontal principal stress (sh) magnitudes range from 90 percent to 92 percent. the following methodology can be used to create geomechanical finite element models for a variety of reservoir types, including the finite element model's in situ stresses inside the inter-well space and undrilled areas of the reservoir are validated versus stress orientation [29]. at the same time, jean and sukumar use the finite element extended approach to convert a 3d fault model into a geomechanical reservoir model by considering hard solid displacement and pore pressure in a threedimensional -mechanical model (fexm). using a mohrcoulomb type criterion in geomechanics, the fault is treated as an internal displacement discontinuity that allows slippage [30]. nicola castelletto et al, in 2016 suggestion that work with fem for heterogeneous media can help for solved the problem of geomechanics in equilibrium state. a range of numerical experiments using synthetic or realistic geomechanical parameters are used to test the approach. the numerical findings show that the multiscale technique is capable of delivering precise results [31]. in 2017, osman hamid et al built a 3d and 4d model utilizing visage for fem analysis for geomechanics investigations and the software eclipse for pressure drop prediction in carbonate reservoir weak formation as shown in fig. 6. the formation's compaction has an impact on not just the weaker rock, but rather the overburdened and the under burden. according to the models, permeability decreased by 18% as the formation was depleted. such discoveries are critical for future improvement, particularly in difficult places where stress sensitivity is high [32]. in the same year, yarlong wang proposed a dual porosity model for two-phase fluid flow in fracture reservoirs. using fem to create a saturation formula with time and pressure, he discovered that the single porosity model may be used for two-phase flow. the impact of two-phase flow on the geomechanics aspect of difficulties will be the focus of future studies, which will focus on the saturation change on pore pressure and effective stresses. alternatively, the skeletal deformation as a function of saturation change will be fascinating [33]. for the purpose of determining the stability of a wellbore, bharatsai created a muster case study in 2017, a. k. faraj and h. a. abdul hussein / iraqi journal of chemical and petroleum engineering 24,1 (2023) 113 124 118 for which a geomechanical model was built to discuss these issues and determine the modification and changes of the reservoir's geomechanical properties, as well as to measure the magnitude and direction of in-situ stresses. after that, he created a 3-d finite geomechanical model that included the formation's elastic anisotropy. due to a larger young's modulus value for middle bakken sandstone, the stress change caused by the thermal effect on drilling fluid on the borehole wall is greater for the middle bakken formation than for the upper and lower bakken formations [34]. babak et al. (2018) used the 3d finite element method to create an optimized confirm the meshing system for the well hole stability study. modeling the state of stresses surrounding the wellbore as shown in fig. 7 with this meshing technique yielded satisfactory agreement with drilling data in both fem approaches. analytical estimates as early warning signs of wellbore instability & breakdown, radial strain, and displacement measurements are presented [35]. in 2018, wei zhang et al. presented the finite-element smoothed particle method (fespm), which is utilized to solve large-scale issues in geomechanics. they discovered that the fespm has advantages over the original pfem in that the entire field variables are determined via recurrent information transit between the particles and the points of gaussian distribution, which eliminates any errors or added difficulty to the solution technique. the fespm has been proven to be a promising numerical method for studying big problems in geomechanics [36]. fig. 5. ground stress rates for (a) well kg, (b) well ks. profiles of earth stress for (a) well kg and (b) well ks. hydrostatic pressure, high pore pressure, minimum horizontal stress, fracture pressure, and vertical stress are indicated by lines 1, 2, 3, 4, and 5. the leak-off test (lot) and rft pressure levels are represented by the star and triangle symbols [29] jun et al. published a paper in 2019 that focuses on the construction of bridges. the finite element technique models fault deformation and fluid flow inside the reservoir during the flow cycle. in this study, the finite element method is used to assess flow back around hydraulic fractures in complex fracture networks, taking into consideration the combined impacts of flow and geomechanics. because of the linked effects, the complex fracture networks in unusual reservoirs and physical characteristics impacts on diverse reservoir porosity and permeability are considerably minimized [37]. in 2020, feizi masouleh used a finite element model, and coupled processes involving matrix deformation and fluid flow were studied. the reservoir's stress varies as a result of production from a propped open fracture. the stress change, on the other hand, is anisotropic. this shift in stress occurs near the horizontal well that is generating it. the novel numerical poroelastic solution allows for more realistic estimations of stress & pore pressure distribution near fractures, enabling the creation of better products [38]. chen et al, in 2021 overcome the problem of continuous grid corner points and calculation failure, a finite volume approach one-way coupling model implemented in the c++ programming language has been developed to compute the distribution of the subsurface stress field. the findings show that a finite method is a viable tool for thermal, hydraulic, and mechanical simulation [39]. danesh et al, 2022 used the finite element method to simulate a 2d natural gas couple model and found that the subsidence was greater at the start of production and subsequently declined and that as production increased, the subsidence rate also increased a. k. faraj and h. a. abdul hussein / iraqi journal of chemical and petroleum engineering 24,1 (2023) 113 124 119 [40]. in the same year, yingli xia et al. used a finite element model to combine (water/gas) with a geomechanical model and discovered that the shear stress grew during production, producing sand migration and an increase in vertical subsidence. when the ratios of permeable anisotropy were raised, the max subsidence increased by around 81 percent [41]. yuyang liu et al. proposed a method for calculating effective stress in low permeability (k) reservoirs by combining the mechanical and flow models in 2022. the results show that by using 3d geological models paired with various numerical approaches, the proposed methods may be utilized to create the effective stress (σe) and pore pressure fields in a reservoir and then forecast the σe value in the reservoir [42]. when some researchers utilize this technology, it begins to be employed in the oil fields of iraq. in the rumelia oil field, amani et al. developed in 2021 an experimental and numerical approach for determining hydrodynamic fracture and non-fracture for two core. when combined with the ansys finite element program for pressure and velocity distribution, the dual porosity and permeability approach utilized by amani increased productivity for the rumelia core by roughly 10% [43]. in order to determine the vertical and horizontal stress distribution in the depletion reservoir, raed and al-jawad presented a four-dimensional finite element model in 2022. the findings indicate that the mud window will be affected by the change in stress during production, and the maximum horizontal stress reduction was 322 psi [44]. table 3 listed a summary of reservoir finite element. fig. 6. pore pressure depletion during the time [32] fig. 7. von misses stress around wellbore [35] a. k. faraj and h. a. abdul hussein / iraqi journal of chemical and petroleum engineering 24,1 (2023) 113 124 120 table 3. summary of reservoir finite element no author name of study objective year 1 bin xu and ron c.k. wong coupled finite-element simulation of injection well testing in unconsolidated oil sands reservoir using fem stimulation for well injected inside reservoir unconsolidated oil sand. 2013 2 d. wang, m.f. randolph, d.j. white a dynamic large deformation finite element method based on mesh regeneration improve the computational capacity of both static and dynamic analyses that include moving boundaries. 2013 3 a. morillo, et al. development of a finite element computer simulation platform for a coupled reservoir and geomechanics system the improvement for fem software program for the modeling, analysis, and simulation. 2014 4 dip kumar singha and rima chatterjee geomechanical modeling using finite element method for prediction of in-situ stress in krishna–godavari basin, india determined these rock properties and prediction the three import stress by using 2d stress model. 2015 5 jean h. prévost and n. sukumar faults simulations for three-dimensional reservoir-geomechanical models with the extended finite element method make 3d faults model for reservoirgeomechanical by consider hard solid displacement and pore pressure in a three-dimensional mechanical mode. 2015 6 nicola castelletto , hadi hajibeygi and hamdi a. tchelepi multiscale finite-element method for linear elastic geomechanics suggestion formula work for solve geomechanical troubles in equilibrium state. 2016 7 hamid, osman, ahmed omair, and pablo guizada. reservoir geomechanics in carbonates building a 3d and 4d model using the finite element method for geomechanical studies and the fluid flow simulator eclipse. 2017 8 yarlong wang two phase flow coupled to geomechanics with dual porosity model: simulating fractured reservoirs by finite element method introduced dual porosity model for two phase fluid flow in fracture reservoir using finite method 2017 9 bharatsai alla wellbore stability analysis of sanish field using 3-d finite element model: bakken case study geomechanical model was built to discuss problems and to determine the modification and changes of the geomechanical properties 2017 10 babak ravaji, sohrab mashadizade and abdolnabi hashemi introducing optimized validated meshing system for wellbore stability analysis using 3d finite element method build an optimized confirm meshing system for the wellbore constancy analysis using 3d finite element method 2018 11 wei zhang ; weihai yuan and beibing dai smoothed particle finite-element method for large-deformation problems in geomechanics. show techniques called finite-element smoothed particle method 2018 12 jun et al. flow back analysis of complex fracture networks in the unconventional reservoir using finite element method with coupled flow and geomechanics. finite element method is used to assess flow back around hydraulic fractures in complex fracture networks 2019 13 feizi masouleh geomechanical modeling of reservoir using finite element method. used a finite element model, and coupled processes involving matrix deformation and fluid flow 2020 14 chen et al. application of the finite volume method for geomechanics calculation and analysis on temperature dependent poromechanical stress and displacement fields in enhanced geothermal system. finite volume approach one-way coupling model implemented in the c++ programming language has been developed to compute the distribution of the subsurface stress field 2021 15 danesh et al. prediction of interactive effects of cbm production, faulting stress regime, and fault in coal reservoir: numerical simulation. used the finite element method to simulate a 2d natural gas couple model and found that the subsidence. 2022 16 yingli xia et al. geomechanical response induced by multiphase (gas/water) flow in the mallik hydrate reservoir of canada. used a finite element model to combine (water/gas) with a geomechanical model. 2022 17 yuyang liu et al. an approach for predicting the effective stress field in low-permeability reservoirs based on reservoir-geomechanics coupling. calculating effective stress in low-k reservoirs by combining the mechanical and flow models. 2022 18 majeed, amani j., ahmed almukhtar, falah a. abood, and ahmed k. alshara numerical study of the natural fracture using dual porosity-dual permeability model for rumaila field, southern iraq. experimental and numerical approach for determining hydrodynamic fracture and non-fracture for two core. when combined with the ansys finite element program for pressure and velocity distribution. 2021 19 allawi, raed h., and mohammed s. al-jawad. 4d finite element modeling of stress distribution in depleted reservoir of south iraq oilfield. presented a four-dimensional finite element model. 2022 a. k. faraj and h. a. abdul hussein / iraqi journal of chemical and petroleum engineering 24,1 (2023) 113 124 121 5conclusion the objective of this study was to provide some background information on the fem's history and a summary of its current engineering problem-solving abilities. it is crucial to remember that the method's initial development was fully focused on how to generate equations for the approach, use them in practical applications, calculate the stresses of aircraft, and utilize them in computer programs. the method was developed to encompass solving any engineering problem; it was used to calculate stresses in geomechanical investigations and to generate 1d, 2d, and 3d models as well as to determine how fluid flow affected reservoir pressure and how those changes affected on stresses. presently, modern technology allows for the discretization and division of almost anything into finite elements, whether it be a solid, liquid, or gas by creating 3d and 4d models to connect the geomechanical and reservoir models. therefore, it is imperative that all nations realize that the effective application of the finite element method is their most important tool for development. the history of the finite element method, the utility of employing this method, and the problems that can be solved using fem are all covered in this study. these formulated equations are required by the oil and gas business in order to make changes to problems that may arise in the future. in a word, the finite element method is the way of the future; it has a lot of power, which we will hopefully realize in the following years. abbreviations acronym definition 1d one-dimensional 2d twodimensional 3d threedimensional fem finite element methods dpm dynamic program method fdem finite discrete element method fexm finite element extended method edm element discrete method sfem stabilized finite element methods fic finite calculus ssr shear strength reduction fet finite element techniques fes finite element slop gls galerkin's least square bhp bottom hole pressure lfem large finite element method mimss meshing and interpolation mechanism small strain fecs finite element computer simulation fespm finite-element smoothed particle method σe effective stress references [1] shaban dharb, and hassan abdul hadi, "geomechanical analysis to avoid serious drilling hazards in zubair oilfield, southern iraq," in iraqi journal of science ,2020, pp.1994-2003, https://doi.org/10.24996/ijs.2020.61.8.16. [2] saleh, talib a, "using sonic log to predict abnormal pressure zones in selected oil wells (western of iraq)," iraqi journal of chemical and petroleum engineering, vol. 15, no. 2 ,2014, pp. 914. [3] logan, daryl l,” a first course in the finite element method,” 6nd ed., cengage learning. canada, 2016. [4] hrennikoff, alexander paul, "plane stress and bending of plates by method of articulated framework," phd diss., massachusetts institute of technology, 1940. [5] mchenry, douglas, "a lattice analogy for the solution of stress problems," in journal of the institution of civil engineers, vol. 21, 1943, pp. 59-82, https://doi.org/10.1680/ijoti.1943.13967. [6] levy, samuel, "computation of influence coefficients for aircraft structures with discontinuities and sweepback," in journal of the aeronautical sciences, vol.14, 1947, pp. 547-560, https://doi.org/10.2514/8.1454. [7] levy, samuel, "structural analysis and influence coefficients for delta wings," in journal of the aeronautical sciences, vol. 20, 1953, pp. 449-454, https://doi.org/10.2514/8.2690. [8] turner, m. jon, ray w. clough, harold c. martin, and l. j. topp, "stiffness and deflection analysis of complex structures," in journal of the aeronautical sciences, vol.23, 1956, pp.805-823, https://doi.org/10.2514/8.3664. [9] gallagher, richard h., joseph padlog, and p. p. bijlaard, "stress analysis of heated complex shapes," in ars journal, vol.32, 1962, pp.700-707, https://doi.org/10.2514/8.6128. [10] archer, john s, "consistent matrix formulations for structural analysis using finite-element techniques," in aiaa journal, vol. 3,1965, pp.1910-1918, https://doi.org/10.2514/3.3279. [11] zienkiewicz, o. c., m. watson, and i. p. king, "a numerical method of visco-elastic stress analysis," international journal of mechanical sciences, vol.10, 1968, pp.807-827, https://doi.org/10.1016/00207403(68)90022-2. [12] zienkiewicz, o. c., and c.j. parekh, "transient field problems: two‐dimensional and three‐dimensional analysis by isoparametric finite elements," in international journal for numerical methods in engineering, vol. 2,1970, pp. 61-71, https://doi.org/10.1002/nme.1620020107. [13] belytschko, ted, "a survey of numerical methods and computer programs for dynamic structural analysis," in nuclear engineering and design, vol.37, 1976, pp.23-34, https://doi.org/10.1016/0029-5493(76)90050-9. https://doi.org/10.24996/ijs.2020.61.8.16 https://www.iasj.net/iasj/download/d30c6508fdd184c6 https://www.iasj.net/iasj/download/d30c6508fdd184c6 https://www.iasj.net/iasj/download/d30c6508fdd184c6 https://www.iasj.net/iasj/download/d30c6508fdd184c6 https://www.iasj.net/iasj/download/d30c6508fdd184c6 http://oastats.mit.edu/handle/1721.1/64833 http://oastats.mit.edu/handle/1721.1/64833 http://oastats.mit.edu/handle/1721.1/64833 http://oastats.mit.edu/handle/1721.1/64833 https://doi.org/10.1680/ijoti.1943.13967 https://doi.org/10.2514/8.1454 https://doi.org/10.2514/8.2690 https://doi.org/10.2514/8.3664 https://doi.org/10.2514/8.6128 https://doi.org/10.2514/3.3279 https://doi.org/10.1016/0020-7403(68)90022-2 https://doi.org/10.1016/0020-7403(68)90022-2 https://doi.org/10.1002/nme.1620020107 https://doi.org/10.1016/0029-5493(76)90050-9 a. k. faraj and h. a. abdul hussein / iraqi journal of chemical and petroleum engineering 24,1 (2023) 113 124 122 [14] zienkiewicz, o., john lyness, and d. j. r. d. j. r. owen, "three-dimensional magnetic field determination using a scalar potential--a finite element solution," in ieee transactions on magnetics, vol.13, 1977, pp.1649-1656, https://10.1109/tmag.1977.1059650. [15] zou, jin-zhang, david j. williams, and wen-lin xiong, "search for critical slip surfaces based on finite element method," in canadian geotechnical journal, vol.32, 1995, pp.233-246, https://doi.org/10.1139/t95-026. [16] wan, j., l. j. durlofsky, t. j. r. hughes, and k. aziz, "stabilized finite element methods for coupled geomechanics-reservoir flow simulations," in spe reservoir simulation symposium. one petro, 2003, https://doi.org/10.2118/79694-ms. [17] onate, e., and j. rojek, "combination of discrete element and finite element methods for dynamic analysis of geomechanics problems," in computer methods in applied mechanics and engineering, vol. 193, 2004, pp.3087-3128, https://doi.org/10.1016/j.cma.2003.12.056. [18] hammah, reginald e., john h. curran, t. e. yacoub, and brent corkum, "stability analysis of rock slopes using the finite element method," in proceedings of the isrm regional symposium eurock. 2004. [19] liu, q., t. stone, g. han, r. marsden, and g. shaw, "coupled stress and fluid flow using a finite element method in a commercial reservoir simulator," in spe asia pacific oil and gas conference and exhibition. one petro, 2004, https://doi.org/10.2118/88616-ms. [20] du, j., and r. c. k. wong, "development of a coupled geomechanics-thermal reservoir simulator using finite element method," in canadian international petroleum conference. one petro, 2005, https://doi.org/10.2118/2005-027. [21] juanes, ruben, and birendra jha, "a locally conservative finite element framework for the simulation of coupled flow and reservoir geomechanics," in spe annual technical conference and exhibition. one petro, 2006, https://doi.org/10.2118/102812-ms. [22] tchonkova, maria, john peters, and stein sture, "a new mixed finite element method for poro‐elasticity," in international journal for numerical and analytical methods in geomechanics, vol. 32, 2008, pp.579606, https://doi.org/10.1002/nag.630. [23] lecampion, brice, "an extended finite element method for hydraulic fracture problems," in communications in numerical methods in engineering, vol. 25, 2009, pp.121-133, https://doi.org/10.1002/cnm.1111. [24] mahabadi, omid k., a. lisjak, a. munjiza, and gjijog grasselli, "y-geo: new combined finitediscrete element numerical code for geomechanical applications," in international journal of geomechanics, vol. 12, 2012, pp.676-688, http://dx.doi.org/10.1061/(asce)gm.19435622.0000216. [25] abdullah, hamed h., ameer h. al-saffar, and raed s. jasim, "stresses and displacements analyses around tunnel opening under water body using finite element method (fem) in baghdad city/middle of iraq," iraqi journal of science, vol. 57, 2016, pp.1267-1279. [26] xu, bin, and ron ck wong, "coupled finite‐element simulation of injection well testing in unconsolidated oil sands reservoir," in international journal for numerical and analytical methods in geomechanics, vol. 37, 2013, pp.3131-3149, https://doi.org/10.1002/nag.2182. [27] wang, dong, m. f. randolph, and d. j. white, "a dynamic large deformation finite element method based on mesh regeneration," in computers and geotechnics, vol.54, 2013, pp.192-201, https://doi.org/10.1016/j.compgeo.2013.07.005. [28] morillo, atilio, josé moreno, robert quintero, m. gambús, orlando zambrano, v. marcano, j. araque et al, "development of a finite element computer simulation platform for a coupled reservoir and geomechanics system," in spe latin america and caribbean petroleum engineering conference. one petro, 2014, https://doi.org/10.2118/169431-ms. [29] singha, dip kumar, and rima chatterjee, "geomechanical modeling using finite element method for prediction of in-situ stress in krishna– godavari basin, india," in international journal of rock mechanics and mining sciences, vol. 73, 2015, pp.15-27, https://doi.org/10.1016/j.ijrmms.2014.10.003. [30] prevost, jean h., and n. sukumar, "faults simulations for three-dimensional reservoirgeomechanical models with the extended finite element method," in journal of the mechanics and physics of solids, vol. 86, 2016, pp.1-18, https://doi.org/10.1016/j.jmps.2015.09.014. [31] castelletto, nicola, hadi hajibeygi, and hamdi a. tchelepi, "multiscale finite-element method for linear elastic geomechanics," in journal of computational physics, vol.331, 2017, pp.337-356, https://doi.org/10.1016/j.jcp.2016.11.044. [32] hamid, osman, ahmed omair, and pablo guizada, "reservoir geomechanics in carbonates," in spe middle east oil & gas show and conference. one petro, 2017, https://doi.org/10.2118/183704-ms. [33] wang, yarlong, "two phase flow coupled to geomechanics with dual porosity model: simulating fractured reservoirs by finite element method," in spe reservoir characterisation and simulation conference and exhibition. one petro, 2017, https://doi.org/10.2118/186067-ms. [34] alla, bharatsai, “wellbore stability analysis of sanish field using 3-d finite element model: bakken case study,” in university of louisiana at lafayette, 2017. https://10.0.4.85/tmag.1977.1059650 https://doi.org/10.1139/t95-026 https://doi.org/10.2118/79694-ms https://doi.org/10.1016/j.cma.2003.12.056 https://www.researchgate.net/profile/brent-corkum/publication/253388721_stability_analysis_of_rock_slopes_using_the_finite_element_method/links/55f97acd08aeafc8ac25aa61/stability-analysis-of-rock-slopes-using-the-finite-element-method.pdf https://www.researchgate.net/profile/brent-corkum/publication/253388721_stability_analysis_of_rock_slopes_using_the_finite_element_method/links/55f97acd08aeafc8ac25aa61/stability-analysis-of-rock-slopes-using-the-finite-element-method.pdf https://www.researchgate.net/profile/brent-corkum/publication/253388721_stability_analysis_of_rock_slopes_using_the_finite_element_method/links/55f97acd08aeafc8ac25aa61/stability-analysis-of-rock-slopes-using-the-finite-element-method.pdf https://www.researchgate.net/profile/brent-corkum/publication/253388721_stability_analysis_of_rock_slopes_using_the_finite_element_method/links/55f97acd08aeafc8ac25aa61/stability-analysis-of-rock-slopes-using-the-finite-element-method.pdf https://www.researchgate.net/profile/brent-corkum/publication/253388721_stability_analysis_of_rock_slopes_using_the_finite_element_method/links/55f97acd08aeafc8ac25aa61/stability-analysis-of-rock-slopes-using-the-finite-element-method.pdf https://doi.org/10.2118/88616-ms https://doi.org/10.2118/2005-027 https://doi.org/10.2118/102812-ms https://doi.org/10.1002/nag.630 https://doi.org/10.1002/cnm.1111 http://dx.doi.org/10.1061/(asce)gm.1943-5622.0000216 http://dx.doi.org/10.1061/(asce)gm.1943-5622.0000216 https://ijs.uobaghdad.edu.iq/index.php/eijs/article/view/7355 https://ijs.uobaghdad.edu.iq/index.php/eijs/article/view/7355 https://ijs.uobaghdad.edu.iq/index.php/eijs/article/view/7355 https://ijs.uobaghdad.edu.iq/index.php/eijs/article/view/7355 https://ijs.uobaghdad.edu.iq/index.php/eijs/article/view/7355 https://ijs.uobaghdad.edu.iq/index.php/eijs/article/view/7355 https://doi.org/10.1002/nag.2182 https://doi.org/10.1016/j.compgeo.2013.07.005 https://doi.org/10.2118/169431-ms https://doi.org/10.1016/j.ijrmms.2014.10.003 https://doi.org/10.1016/j.jmps.2015.09.014 https://doi.org/10.1016/j.jcp.2016.11.044 https://doi.org/10.2118/183704-ms https://doi.org/10.2118/186067-ms https://www.proquest.com/openview/36292585b06be608909b9e2e79fd4511/1?pq-origsite=gscholar&cbl=18750 https://www.proquest.com/openview/36292585b06be608909b9e2e79fd4511/1?pq-origsite=gscholar&cbl=18750 https://www.proquest.com/openview/36292585b06be608909b9e2e79fd4511/1?pq-origsite=gscholar&cbl=18750 https://www.proquest.com/openview/36292585b06be608909b9e2e79fd4511/1?pq-origsite=gscholar&cbl=18750 a. k. faraj and h. a. abdul hussein / iraqi journal of chemical and petroleum engineering 24,1 (2023) 113 124 123 [35] ravaji, babak, sohrab mashadizade, and abdolnabi hashemi, "introducing optimized validated meshing system for wellbore stability analysis using 3d finite element method," in journal of natural gas science and engineering, vol. 53, 2018, pp.74-82, https://doi.org/10.1016/j.jngse.2018.02.031. [36] wei, zhang, yuan weihai, and dai beibing, "smoothed particle finite-element method for large-deformation problems in geomechanics," in american society of civil engineers, 2018, https://doi.org/10.1061/(asce)gm.19435622.0001079. [37] li, jun, yuetian liu, liang xue, ziyan cheng, xiangming kong, and songqi li, "flow back analysis of complex fracture networks in the unconventional reservoir using finite element method with coupled flow and geomechanics," in abu dhabi international petroleum exhibition & conference. one petro, 2019, https://doi.org/10.2118/197372-ms. [38] feizi masouleh, shahla, "geomechanical modeling of reservoir using finite element method," in 2020. [39] chen, peipei, jiang sun, chunyang lin, and wei zhou, "application of the finite volume method for geomechanics calculation and analysis on temperature dependent poromechanical stress and displacement fields in enhanced geothermal system," in geothermics, vol.95, 2021, pp.102138.2021, https://doi.org/10.1016/j.geothermics.2021.102138. [40] danesh, nima noraei, yixin zhao, teng teng, and mohsen s. masoudian, "prediction of interactive effects of cbm production, faulting stress regime, and fault in coal reservoir: numerical simulation," in journal of natural gas science and engineering, vol.104419,2022, https://doi.org/10.1016/j.jngse.2022.104419. [41] xia, yingli, tianfu xu, yilong yuan, xin xin, and huixing zhu, "geomechanical response induced by multiphase (gas/water) flow in the mallik hydrate reservoir of canada," in spe journal, vol. 27, 2022, pp.434-451, https://doi.org/10.2118/206746-pa. [42] liu, yuyang, xiaowei zhang, wei guo, lixia kang, rongze yu, and yuping sun, "an approach for predicting the effective stress field in lowpermeability reservoirs based on reservoirgeomechanics coupling," in processes, vol.10, 2022, pp.633.2022, https://doi.org/10.3390/pr10040633. [43] majeed, amani j., ahmed al-mukhtar, falah a. abood, and ahmed k. alshara, "numerical study of the natural fracture using dual porosity-dual permeability model for rumaila field, southern iraq," arabian journal of geosciences, vol. 14, 2021, pp.1-9, https://doi.org/10.1007/s12517-021-08229-2. [44] allawi, raed h., and mohammed s. al-jawad, "4d finite element modeling of stress distribution in depleted reservoir of south iraq oilfield," journal of petroleum exploration and production technology, vol. 12, 2022, pp. 679-700, https://doi.org/10.1007/s13202-021-01329-5. https://doi.org/10.1016/j.jngse.2018.02.031 https://doi.org/10.1061/(asce)gm.1943-5622.0001079 https://doi.org/10.1061/(asce)gm.1943-5622.0001079 https://doi.org/10.2118/197372-ms https://shareok.org/handle/11244/326642 https://shareok.org/handle/11244/326642 https://doi.org/10.1016/j.geothermics.2021.102138 https://doi.org/10.1016/j.jngse.2022.104419 https://doi.org/10.2118/206746-pa https://doi.org/10.3390/pr10040633 https://doi.org/10.1007/s12517-021-08229-2 https://doi.org/10.1007/s13202-021-01329-5 a. k. faraj and h. a. abdul hussein / iraqi journal of chemical and petroleum engineering 24,1 (2023) 113 124 124 بحث مراجعةالمحدودة: تقنية العناصر قاتتطبي 1 حسن عبد الهادي عبد الحسينو ، *2، 1علي خليل فرج قسم هندسة النفط، كلية الهندسة، جامعة بغداد، العراق 1 العراق، الجامعة التكنولوجية ط،قسم تكنولوجيا النف 2 الخالصة يتم استخدام نهج العناصر المحدودة لحل مجموعة متنوعة من الصعوبات، بما في ذلك استقرار تجويف ين بي، من البئر، وإنتاج تدفق السوائل وآبار الحقن، والمشكالت الميكانيكية، والهندسة المدنية، والعالج الطب سة همة في صناعة البترول، مثل دراأمور أخرى. الميكانيكا الجيولوجية مصطلح يشمل عدًدا من الجوانب الم أثناء التغيرات التي يمكن أن تحدث في مكامن النفط والهياكل الجيولوجية وتقديم صورة الستقرار آبار النفط في femالعناصر المحدودة الحفر. سيكون هذا البحث دراسة مراجعة تعنى بالتطورات في تطبيق طريقة من الزمان.المجال الجيوميكانيكي على مدار قرن يكلي كان أول شيء في هذه الدراسة هو تقديم التطورات المبكرة لهذه الطريقة من خالل تطوير اإلطار اله ن اني كاللضغط، وعمل حل كمبيوتر رقمي لإلجهاد الحراري ثنائي األبعاد ثم تحليل اإلجهاد للطائرة. الجزء الث وهذه الطريقة تولد تقنيات جديدة لحل هذه المشاكل، مثل نماذج العناصر femيقدم أحدث التطورات في لمنفصلة ؛ طريقة العناصر المحدودة اdpmطريقة البرنامج الديناميكي ة احادي وثنائي وثالثي االبعاد،المحدود fdem ؛ وطريقة العناصر المحدودة الممتدةfexmعنصر . تم تقديم الجزء الثالث من هذه الدراسة لمحاكاة feالخزان المحدود المستخدم في اختبار بئر الحقن داخل خزانات النفط غير المجمعة، وتحسين برنامج نموذج للتحليالت، ونهج ممتد للعناصر المحدودة لتحويل نموذج ثالثي األبعاد، وبناء نموذج ثالثي األبعاد و ض للتنبؤ بانخفا eclipse برنامجو نيكا لتحقيقات الجيوميكا femلتحليل visageرباعي األبعاد باستخدام الضغط في التكوين الضعيف لخزان الكربونات وعرض طريقة الجسيمات المتناهية للعنصر المتناهي fespm طريقة العناصر المحدودة سوف تتألق في المستقبل، وتطبيقاتها في مجموعة متنوعة من العلوم . الهندسة المدنية والجيولوجية، ستصل إلى قوتها تماًما.الهندسية، ال سيما في مشاكل صناعة البترول و يناميكي.نموذج برنامج د موديل جيوميكانيكي، طريقة العناصر المنفصلة المحدودة، الكلمات الدالة: طريقة العناصر المحدودة، available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.23 no.3 (september 2022) 67 – 73 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: fatima mahmood shaker , email: fatima.shaker2008m@coeng.uobaghdad.edu.iq , name: dhifaf jaafar sadeq, email: dhifaf.sadeq@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. risk-based inspection due to corrosion consequences for oil and gas flowline: a review fatima mahmood shaker a and dhifaf jaafar sadeq b a basra oil company, rumaila oil filed, iraq d department of petroleum engineering, university of baghdad, baghdad, iraq abstract the petroleum industry, which is one of the pillars of the national economy, has the potential to generate vast wealth and employment possibilities. the transportation of petroleum products is complicated and changeable because of the hazards caused by the corrosion consequences. hazardous chemical leaks caused by natural disasters may harm the environment, resulting in significant economic losses. it significantly threatens the aim for sustainable development. when a result, determining the likelihood of leakage and the potential for environmental harm, it becomes a top priority for decision-makers as they develop maintenance plans. this study aims to provide an in-depth understanding of the risks associated with oil and gas pipelines. it also tries to identify essential risk factors in flowline projects, as well as their likelihood and severity, in order to reduce loss of life and increased expenditures as a result of safety issues. the monetary quantification was used to determine the leakage-induced environmental losses. using a 5-by-5 probability-currency matrix, the level of environmental risk was evaluated the safety and risk-based inspection (rbi) is evaluated through the use of specific schedules to determine the likelihood of failure (lof) and consequence of failure (cof). the risk level appears in the matrix, and appropriate maintenance steps should be taken to reduce risks, such as injecting corrosion inhibitors to protect the pipelines, activating cathodic protection or coating. overall, this research contributes to the prevention of petroleum product leakage due to the corrosion consequences in the transportation sector. also, encourage non-environmental risk decisionmakers to gain a better understanding of the risk level. keywords: oil leakage, risk-based inspection (rbi), likelihood of failure (lof), consequence of failure (cof) received on 11/05/2022, accepted on 26/06/2022, published on 30/09/2022 https://doi.org/10.31699/ijcpe.2022.3.9 1introduction the petroleum resources are distributed unevenly, longdistance transportation is necessary. vehicles, ships, and flowlines are the most common modes of transportation, with flowline transportation accounting for the vast bulk of these techniques. natural catastrophes will cause damage to infrastructure due to external destructive power in the event of long-distance transit based on flowlines, due to weak infrastructure, inadequate information sharing systems, and small-scale human development programs, developing countries are disproportionately affected by natural disasters. however, the countries adopted a number of measures to minimize economic losses, including disaster management programs, social safety programs, and human development programs. countries are that face severe challenges of flood, storm, epidemic, extreme temperature, etc., which affect its economic productivity [1], [2] resulting in hazardous chemical leakage. as a result, there will be significant environmental damage and economic loss, which cannot be overlooked in day-to-day operations. in 2010, an oil flowline in michigan, the united states, burst, spewing 4.5 million liters of oil into the kalamazoo river, in arkansas, an oil flowline burst in 2013, forcing the evacuation of more than twenty homes [3],[4]. that said, it is imperative to ensure the safe operation of the conveying installation by a number of preventive measures, especially for metal flow lines over long distances. among these, risk assessment is a critical connection that can identify local regions prone to leakage, allowing for targeted and timely maintenance and repair. risk assessment is the foundation for preventing and reducing environmental risks, which is an urgent demand for sustainable energy supply and societal development [5],[6]. the work of quantitative risk assessment includes determining the likelihood of the danger occurring and its implications. the first goal of this project is to forecast the likelihood of natural disaster-related dangers [7]. based on the pipeline and hazardous material safety administration (phmsa). the proposed model can indicate the evaluation's objectivity. the correctness of the judgment, on the other hand, was entirely dependent on the database's applicability. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:fatima.shaker2008m@coeng.uobaghdad.edu.iq mailto:dhifaf.sadeq@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2022.3.9 f. m. shaker and d. j. sadeq / iraqi journal of chemical and petroleum engineering 23,3 (2022) 67 73 68 because of the large gap between the operational environment and the management level, not all flowlines were appropriate for the disclosed historical failure database. as a result, academics have devised the index score and fault tree approaches [8], [9]. the evaluation index system and basic event table for assessment were built after a thorough examination of the internal and external reasons of flowline failure. with limited historical fault data samples, the fuzzy comprehensive evaluation approach and expert judgment method utilized to assess risk were suitable for quantitative evaluation. and to provide a theoretically low failure rate over the flowline's lifetime there are methods for ensuring flowline reliability during service, such as corrosion control and routine-based maintenance [10],[11]. 2what is risk risk is diagnosed as the consequences of threat or chance of its incidence. in other words, risk is a processing which special strategies are used to take a look at the probability of a threat and additionally its impacts, the consequences are supplied primarily based totally on the intensity of studies and the quantitative or qualitative phases. the likelihood of an unexpected or unfavorable outcome can be referred to as risk. risk is any action or activity that increases the possibility of suffering a loss of any kind. a company may encounter and have to deal with a variety of dangers. risks can generally be divided into three categories: financial risk, non-business risk, and business risk, the method carries figuring out probabilistic risks, predicting the area of incidence, estimating the probability of incidence and effect evaluation. hazard refers to the properties which have the capability of inflicting a catastrophe at the same time as danger is threat possibility and its severity which can cause damage. when a pipeline has been assessed, in a reality the threat probability and its impacts in a precise section of the pipeline in step with the environmental conditions are depicted in a specific moment. in this situation it should be said that environmental risk evaluation consists of figuring out the affected surroundings, time and spatial modeling of emissions and leakage, evaluation of essential ecologically components concerning environmental sensitivity, estimation of quantity of the threat in comparison with current requirements and figuring out danger mitigate actions. accordingly, further to take a look at and evaluation various elements of hazard with complete acknowledgement to the environment of the area, environmental sensitivity, and additionally environmental values are used in the danger evaluation risk analysis involves answering the following three questions [12],[13]:  what can go wrong  how can it happen  what are the consequences the set r of the above three questions can be mathematically expressed as: r = {si, pi, xi}, i = 1, 2, n (1) where: si is an event or an occurrence, pi is the probability of si and xi is the consequence of si 3risk based inspection process (purpose & methodology) flowline risk evaluations will be qualitative, as is common in the industry. fig. 1 depicts a high-level summary of risk management philosophy [14], [15], [16], [17] fig. 1. risk assessment process flowchart [18], [19] the purpose of an rbi analysis is to focus inspection efforts the sections of the flowline most at risk of failure with respect to an active damage mechanism. in rbi, risk is defined as the sum of the probability and consequences of failure in terms of math [20], [21]. risk = lof x cof (2) where: lof = likelihood of failure cof = consequence of failure 3.1. likelihood of failure (lof) likelihood of failure or the likelihood factor is the sum of equipment factor (ef), damage factor (df), inspection factor (if), condition factor (cof), process factor (pf) and mechanical design factor (mdf). lof = ef+ df +if + cof + pf+ mdf (3) a. equipment factor the criteria to define are determined by the size of the considered system. b. damage factor is a measurement of the risk linked with known damage mechanisms that are active or potentially active in the process in assessment. c. the inspection factor is a measure of the inspection program's success in identifying the unit's active or expected damage processes. f. m. shaker and d. j. sadeq / iraqi journal of chemical and petroleum engineering 23,3 (2022) 67 73 69 d. the condition factor is used to assess how well plant maintenance e. the process factor is a measure of the likelihood that aberrant operations or disturbed conditions may trigger events that will result in a loss of containment. f. the mechanical design factor assesses various features of the equipment used in the operation. 3.2. consequence of failure (cof) the failure consequence or consequence factor is the sum of the chemical factor (cf), quantity factor (qf), state factor (sf), auto ignition factor (af), pressure factor (prf) and credit factor (cf). cof = cf + qf + sf + af + prf + cf (4) chemical factor is a measure of a chemical's inherent potential to ignite. it is based on material that makes up the majority or is typical of the tank contents. the nfpa flammable hazard rating for flash and reactivity is used to calculate the chemical factor [22]. a. quantity factor represents the maximum number of materials that could be discharged from a unit in a single scenario b. the state factor is determined by the fluid's typical boiling point, which indicates how quickly the fluid will evaporate and scatter when released into the environment. c. the auto-ignition factor is a penalty that is applied to fluid that is treated at a temperature higher than the auto-ignition temperature. d. the pressure factor denotes the fluid's proclivity for being released quickly, resulting in a higher likelihood of immediate type effects. e. credit factor is the sum of multiple sub-factors of technical systems in place that might mitigate event damage. in order to carry out the risk assessment, the likelihood category and damage consequence category are determined from the likelihood factor and the consequence factor respectively by using risk assessment matrix. 4risk matrix the risk matrix approach can be used to assess the likelihood and severity of losses in flow lines to establish future maintenance plans [23]. based on the results of the risk calculation and the risk matrix, decision makers can evaluate the risk level and develop targeted programs to decrease environmental risks [24]. 4.1. probability impact matrix the probability and impact of an event's occurrence are assigned to the total on a random basis, which may be a specific classification, making risk computation quite simple as shown in table 1. [25-32]. table 1. streamlined model of the probability and impact classification calcsilicate probabilities score impact classification score low 1 major 3 medium 2 medium 2 high 3 easily 1 the risk manager or project team members will proceed to multiply the two variables after granting the total (scores) for likelihood and impact of risk categories they have identified. the operation's outcome will eliminate any risk. this approach was used to create an impression of the risk of the audience not showing up for the scheduled classes in the project "seminar: trends in the restructuring and modernization of agriculture in the area of the local action group (lag) mountain valley 2013". the first step was to define the probability of risk occurrence by using table 2 [33]. table 2. likelihood score risk level of likelihood score very low 0-20 low 21-40 medium 41-60 high 61-80 very high 81-100 the second step was to set the impact on a scale of 1 to 5 by using table 3 [33]. table 3. impact analysis magnitude of impact impact definition score rating high impact/ high probability very high they are the most serious threats to which business owners should be vigilant. 5 a high impact / medium probability medium impact /high probability high these dangers have a high chance of happening or having a significant impact. 4 b medium impact / medium probability medium the chances of the risks having an impact are medium. 3 c medium impact / low probability low impact / medium probability low these risks can occur in a variety of circumstances and have a low to medium impact. 2 d low impact / low probability insignificant there are risks that have a low likelihood of occurring and having a low impact. as a result, it is possible to overlook it. 1 e the third step was to compute the risk exposure values as shown in table 4. f. m. shaker and d. j. sadeq / iraqi journal of chemical and petroleum engineering 23,3 (2022) 67 73 70 table 4. calculation of the exposure risk nr. cart. risk occurrence likelihood* impact* degree of risk exposure ** probability score probability score rating score 1. without learners very low 20 very high 5 e 12,5 2. a small number low 40 high 4 d 22 3. reasonable number medium 60 medium 3 c 31,5 4. full house high 80 low 2 b 41 5. more than places very high 100 very low 1 a 50,5 in the final stage, a risk matrix was created, as illustrated in fig. 2. fig. 2. risk categories of flowlines 5categorization of risk a 5x5 matrix of likelihood and consequence, as shown in fig. 2., is used to create risk categories. there are five categories of probability (1 is the lowest probability and 5 is the highest probability of failure) and five consequence categories (a being the lowest and e being the worst consequence of failure). colors are used to indicate risk categories in the matrix; for example, red indicates critical, orange indicates unacceptable, yellow indicates tolerable, light green indicates acceptable, and green indicates favorable. for the sake of inspection priority, three degrees of risk ranking are developed. system, group, or equipment items are rated as "high," "medium," or "low" risk based on the results of this risk classification (risk screening): the following three levels of risk have been identified:  low risk – the level of risk is acceptable. in general, action must be performed to ensure that risk remains contained within this zone; often, this entails operator rounds, cleaning, and basic visual checks to ensure that equipment condition has not changed.  medium risk the risk is acceptable. to guarantee that hazards do not escalate into the red high-risk region, action (such as ndt and other condition monitoring activities) should be conducted to measure the level of deterioration.  high risk the risk is too high. to keep risk within an acceptable range, action must be made to reduce probability, consequence, or both [34],[35],[36].  6remaining life assessment the chance of failure from general internal or external wall thinning was determined when available for static pressure equipment and flowlines based on information provided in the relevant, historical inspection reports utilizing wall thickness measurement data. the internal corrosion likelihood was calculated using a long-term corrosion rate derived from wall thickness measurement data, while the external corrosion likelihood was calculated using an in-built corrosion rate derived from the level of environmental exposure and the condition of the external coating. the remaining life eq. (5) was calculated using the worst-case corrosion rate eq. (6) as follows [37]: cr = (𝑁𝑊𝑇−𝑀𝑊𝑇) (𝐷𝑎𝑡𝑒 𝑜𝑓 𝑖𝑛𝑠𝑝𝑒𝑐𝑡𝑖𝑜𝑛−𝐷𝑎𝑡𝑒 𝑜𝑓 𝑐𝑜𝑚𝑖𝑠𝑠𝑖𝑜𝑛𝑖𝑛𝑔) (5) rl = 𝑀𝐴𝑇 𝐶𝑅 (6) 7conclusions pipeline failure rates in the production gathering system may be expected to increase exponentially without implementation of a risk assessment. according to the probability of failure (pof) and the consequence value (cof) the risk of limiting the number of pipeline failures in the short-term. the establishment of a functional risk-based integrity management system (rbim) is envisaged. provide the most effective means of managing future integrity to support safe and reliable production. a key element of such a system will be the development of an appropriate strategy for controlling the threat of internal and external corrosion. though not insignificant, developing a strategy for the control of external corrosion is likely to be relatively straight-forward task in comparison to internal corrosion and will entail a combination of soil corrosivity analyses, pipeline inspection, remediation (coating/cp) and/or repair. f. m. shaker and d. j. sadeq / iraqi journal of chemical and petroleum engineering 23,3 (2022) 67 73 71 control of internal corrosion is considered to be the most significant challenge in maintaining safe and reliable operation of the gathering system and is likely to become increasingly challenging as water cuts continue to rise. the solution is likely to entail a combination of chemical corrosion inhibitor injection, use corrosion-resistant materials and reconfiguration of large parts of the gathering system (e.g., routing production fluids through field manifold and trunklines). however, it is expected that an optimized solution may only be established on the basis of a comprehensive feasibility study, which will require input various disciplines within company (including integrity, projects, process and sub-surface optimization) such that the requirements and constraints of each are satisfied. nomenclature symbol description unit rl remaining life years mat minimum allowable thickness mm cr corrosion rate mm/yr nwt nominal wall thickness mm mwt measured wall thickness mm references [1] m. i. qureshi, r. yusoff, s. s. hishan, a. s. a. f. alam, and k. zaman, “natural disasters and malaysian economic growth : policy reforms for disasters management,” no. december 1965, 2019. [2] h. hadi jasim, “evaluation the effect of velocity and temperature on the corrosion rate of crude oil pipeline in the presence of co2/h2s dissolved gases”, ijcpe, vol. 20, no. 2, pp. 41–50, jun. 2019. [3] y.f. cheng,“monitor safety of aged oil pipelines,”nature 529:156, 2016, doi: org/ 10.1007/ s1 1356-020-08184-7 [4] q. sulaiman, a. al – taie, d. m. hassan, and c. of r. and industrial development, “evaluation of sodium chloride and acidity effect on corrosion of buried carbon steel pipeline in iraqi soil”, ijcpe, vol. 15, no. 1, pp. 1–8, mar. 2014. [5] h. wang, j. xu, w. zhao, and j. zhang, “effects and risk evaluation of oil spillage in the sea areas of changxing island,” pp. 8491–8507, 2014, doi: 10.3390/ijerph110808491. [6] b. he, d. zhao, j. zhu, a. darko, and z. gou, “promoting and implementing urban sustainability in china : an integration of sustainable initiatives at different urban scales,” habitat int., no. october, pp. 1–11, 2018, doi: 10.1016/j.habitatint.2018.10.001. [7] k. shan, j. shuai, k. xu, and w. zheng, “failure probability assessment of gas transmission pipelines based on historical failure-related data and modification factors,” j. nat. gas sci. eng., 2018, doi: 10.1016/j.jngse.2018.01.049. [8] w.k. muhlbauer , “pipeline risk management manual ,” 3rd edn,2004, gulf publishing companies, houston [9] p. badida, y. balasubramaniam, and j. jayaprakash, “risk evaluation of oil and natural gas pipelines due to natural hazards using fuzzy fault tree analysis,” j. nat. gas sci. eng., vol. 66, no. april, pp. 284–292, 2019, doi: 10.1016/j.jngse.2019.04.010. [10] j. . v. a. w. dawotola, p.h.a.j.m van gelder, “risk assessment of petroleum pipelines using a combined analytical hierarchy process fault tree analysis,” proc. 7th int. probabilistic work. fac. civ. eng. geosci. delft univ. technol. stevinweg 1, 2628cn delft, netherlands, vol. 13, no. 2006, pp. 491–501, 2009. [11] g. qin, p. zhang, x. hou, s. wu, and y. wang, “risk assessment for oil leakage under the common threat of multiple natural hazards,” environ. sci. pollut. res., vol. 27, no. 14, pp. 16507–16520, 2020, doi: 10.1007/s11356-020-08184-7. [12] d. w. roldán and g. f. m. de souza, “riskbased analysis of lng carriers loading and unloading operations,” proc. int. offshore polar eng. conf., vol. 4, pp. 716–724, 2012. [13] a. i. journal, “environmental science,” science (80-. )., vol. 288, no. 5473, pp. 1943–1943, 2000, doi: 10.1126/science.288.5473.1943a. [14] a. w. al-mithin, v. sardesai, b. al-harbi, h. s. murthy, and a. s. a. hannan, “risk based inspection (rbi) of aboveground storage tanks to improve asset integrity,” int. pet. technol. conf. 2011, iptc 2011, 2011. [15] j. ballesio, h. patel, a. revenga, and p. rynn, “risk assessment and technology qualification process for offshore lng pipelines,” offshore technol. conf. proc., vol. 5, pp. 2944–2952, 2009, doi: 10.4043/otc20301-ms. [16] n. m.j. marley, c.h. jahre-nilsen and o.h. bj~rn~y det norske veritas oslo and abstract, “probability of failure figure 1 rbi management process,” proc. elev. int. offshore pola r eng. conf. stavanger, norway, june 17-22, 2001, vol. 11, 2001. [17] n. hashim ameen, m. kh. mohammad, and t. m. nafae, “risk assessment due to population exposure to lead particles emitted from domestic electrical generators”, ijcpe, vol. 10, no. 3, pp. 19– 23, sep. 2009. [18] p. t. hogelin, j. t. webb, y. ruocco, d. vadel, and r. hill, “risk based internal corrosion assessment of pipe in pipe flowline,” proc. annu. offshore technol. conf., vol. 1, pp. 384–398, 2018, doi: 10.4043/28904-ms. [19] d. i. karsan et al., “risk assessment of a tanker based floating production storage and offloading (fpso) system in deepwater gulf of mexico,” proc. annu. offshore technol. conf., vol. 2, 1999, doi: 10.4043/11000-ms. https://link.springer.com/article/10.1007/s11356-019-04866-z https://link.springer.com/article/10.1007/s11356-019-04866-z https://link.springer.com/article/10.1007/s11356-019-04866-z https://link.springer.com/article/10.1007/s11356-019-04866-z https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/549 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/549 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/549 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/549 https://www.nature.com/articles/529156e https://www.nature.com/articles/529156e https://www.nature.com/articles/529156e https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/263 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/263 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/263 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/263 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/263 https://www.mdpi.com/78674 https://www.mdpi.com/78674 https://www.mdpi.com/78674 https://www.mdpi.com/78674 https://www.sciencedirect.com/science/article/pii/s0197397518302753 https://www.sciencedirect.com/science/article/pii/s0197397518302753 https://www.sciencedirect.com/science/article/pii/s0197397518302753 https://www.sciencedirect.com/science/article/pii/s0197397518302753 https://www.sciencedirect.com/science/article/pii/s0197397518302753 https://www.sciencedirect.com/science/article/pii/s1875510018300702 https://www.sciencedirect.com/science/article/pii/s1875510018300702 https://www.sciencedirect.com/science/article/pii/s1875510018300702 https://www.sciencedirect.com/science/article/pii/s1875510018300702 https://www.sciencedirect.com/science/article/pii/s1875510018300702 https://www.sciencedirect.com/science/article/pii/s1875510019301052 https://www.sciencedirect.com/science/article/pii/s1875510019301052 https://www.sciencedirect.com/science/article/pii/s1875510019301052 https://www.sciencedirect.com/science/article/pii/s1875510019301052 https://www.sciencedirect.com/science/article/pii/s1875510019301052 https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.204.7082&rep=rep1&type=pdf https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.204.7082&rep=rep1&type=pdf https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.204.7082&rep=rep1&type=pdf https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.204.7082&rep=rep1&type=pdf https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.204.7082&rep=rep1&type=pdf https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.204.7082&rep=rep1&type=pdf https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.204.7082&rep=rep1&type=pdf https://link.springer.com/article/10.1007/s11356-020-08184-7 https://link.springer.com/article/10.1007/s11356-020-08184-7 https://link.springer.com/article/10.1007/s11356-020-08184-7 https://link.springer.com/article/10.1007/s11356-020-08184-7 https://link.springer.com/article/10.1007/s11356-020-08184-7 https://onepetro.org/isopeiopec/proceedings-abstract/isope12/all-isope12/isope-i-12-609/12992 https://onepetro.org/isopeiopec/proceedings-abstract/isope12/all-isope12/isope-i-12-609/12992 https://onepetro.org/isopeiopec/proceedings-abstract/isope12/all-isope12/isope-i-12-609/12992 https://onepetro.org/isopeiopec/proceedings-abstract/isope12/all-isope12/isope-i-12-609/12992 https://www.earthdoc.org/content/papers/10.3997/2214-4609-pdb.280.iptc14434_nopw https://www.earthdoc.org/content/papers/10.3997/2214-4609-pdb.280.iptc14434_nopw https://www.earthdoc.org/content/papers/10.3997/2214-4609-pdb.280.iptc14434_nopw https://www.earthdoc.org/content/papers/10.3997/2214-4609-pdb.280.iptc14434_nopw https://www.earthdoc.org/content/papers/10.3997/2214-4609-pdb.280.iptc14434_nopw https://onepetro.org/otconf/proceedings-abstract/09otc/all-09otc/otc-20301-ms/36091 https://onepetro.org/otconf/proceedings-abstract/09otc/all-09otc/otc-20301-ms/36091 https://onepetro.org/otconf/proceedings-abstract/09otc/all-09otc/otc-20301-ms/36091 https://onepetro.org/otconf/proceedings-abstract/09otc/all-09otc/otc-20301-ms/36091 https://onepetro.org/otconf/proceedings-abstract/09otc/all-09otc/otc-20301-ms/36091 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/409 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/409 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/409 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/409 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/409 https://onepetro.org/otconf/proceedings/18otc/d011s006r003/179209 https://onepetro.org/otconf/proceedings/18otc/d011s006r003/179209 https://onepetro.org/otconf/proceedings/18otc/d011s006r003/179209 https://onepetro.org/otconf/proceedings/18otc/d011s006r003/179209 https://onepetro.org/otconf/proceedings/18otc/d011s006r003/179209 https://onepetro.org/otconf/proceedings-abstract/99otc/all-99otc/otc-11000-ms/40500 https://onepetro.org/otconf/proceedings-abstract/99otc/all-99otc/otc-11000-ms/40500 https://onepetro.org/otconf/proceedings-abstract/99otc/all-99otc/otc-11000-ms/40500 https://onepetro.org/otconf/proceedings-abstract/99otc/all-99otc/otc-11000-ms/40500 https://onepetro.org/otconf/proceedings-abstract/99otc/all-99otc/otc-11000-ms/40500 f. m. shaker and d. j. sadeq / iraqi journal of chemical and petroleum engineering 23,3 (2022) 67 73 72 [20] m.j. marley; c.h. jahre-nilsen; o.h. bjørnøy , “rbi planning for pipelines. in the eleventh international offshore and polar engineering conference,”. onepetro., stavanger, norway, june 2001 [21] a. s .maintech, ø .sævik, h. wilson, j. s.mæland, & s. v. g. selboe,. internal integrity management of rigid flowlines. [22] nfpa 704: standard system for the identification of the hazards of materials for emergency response [23] l. hong and y. tang, cheng, (2007) “study on the classification of dangerous hazard evaluation based on risk management method,” china saf sci j 17:145–150,2007, doi:org/10.16265/j.cnki.issn10033033. [24] l. lu, w. liang, l. zhang, h. zhang, z. lu, and j. shan, “a comprehensive risk evaluation method for natural gas pipelines by combining a risk matrix with a bow-tie model,” j. nat. gas sci. eng., vol. 25, pp. 124–133, 2015, doi: 10.1016/j.jngse.2015.04.029. [25] v. dumbravă and i. vladut-severian, “using probability – impact matrix in analysis and risk assessment projects,” j. knowl. manag. econ. inf. technol., vol. 42, no. december, pp. 76–96, 2013, [online]. [26] g. bower-white, “demonstrating adequate management of risk: the move from quantitative to qualitative risk assessments,” soc. pet. eng. spe eur. hse conf. exhib. 2013 heal. safety, environ. soc. responsib. oil gas explor. prod. ind., pp. 221– 231, 2013, doi: 10.2118/164969-ms. [27] r. barson and k. spicer, “pipework and vessel review and risk based assessments of the north sea forties assets,” soc. pet. eng. 5th spe int. conf. oilf. corros. 2010, pp. 103–110, 2010, doi: 10.2118/130525-ms. [28] n. a. valdman, “methodical approaches and results of safety analysis for offshore transport & technological systems,” proc. int. offshore polar eng. conf., vol. 3, pp. 571–578, 2014. [29] t. w. lee and n. s. othman, “managing environmental incidents at oil and gas facilities before they happen,” soc. pet. eng. 9th int. conf. heal. saf. environ. oil gas explor. prod. 2008 "in search sustain. excell., vol. 2, pp. 692–699, 2008, doi: 10.2118/111604-ms. [30] m. s. mcdermott, “risk assessment (hazard management) process is a continual process not a one off,” 2007, doi: 10.2118/108853-ms. [31] r. g. s. suarez, f. c. dumon, l. s. barragan, j. mccarthy, and d. mcfadyen, “a zero accident strategy for oil pipelines: enhancing hse performance,” soc. pet. eng. spe int. conf. exhib. heal. safety, environ. sustain. 2020, hse sustain. 2020, pp. 1–15, 2020, doi: 10.2118/199537-ms. [32] o. abifarin and s. j. mishael, “application of risk management principles to pipeline leak prevention in the niger delta,” int. conf. heal. saf. environ. oil gas explor. prod., pp. 1–7, 2000, doi: 10.2523/62485-ms. [33] f. j. deegan and k. j. moore, “hazard identification and risk assessment of the troll pipeline laying and pull-in,” 2007, doi: 10.2523/35777-ms. [34] p. areeniyom, “the use of risk-based inspection for aging pipelines in sirikit oilfield,” soc. pet. eng. int. pet. technol. conf. 2012, iptc 2012, vol. 3, pp. 2420–2430, 2012, doi: 10.2523/14946-ms. [35] g. hill and j. aarnes, “development of a risk register for an integrated carbon capture and storage project,” carbon manag. technol. conf. 2012, pp. 749–758, 2012, doi: 10.2172/1747969. [36] d. abia, s. ajayi, and m. iwegbu, “technological risk assessment: a panacea to preventing major process incidentsa case study of amenam kpono,” soc. pet. eng. spe niger. annu. int. conf. exhib. 2018, naic 2018, no. oml 99, 2018, doi: 10.2118/193429-ms. [37] s. matthews, m. s. al jaberi, and d. mundyath, “risk based inspection implementation for upstream offshore operator: case study,” soc. pet. eng. 30th abu dhabi int. pet. exhib. conf. adipec 2014 challenges oppor. next 30 years, vol. 3, pp. 1983– 1996, 2014, doi: 10.2118/171862-ms. https://onepetro.org/isopeiopec/proceedings-abstract/isope01/all-isope01/isope-i-01-140/8032 https://onepetro.org/isopeiopec/proceedings-abstract/isope01/all-isope01/isope-i-01-140/8032 https://onepetro.org/isopeiopec/proceedings-abstract/isope01/all-isope01/isope-i-01-140/8032 https://onepetro.org/isopeiopec/proceedings-abstract/isope01/all-isope01/isope-i-01-140/8032 https://onepetro.org/isopeiopec/proceedings-abstract/isope01/all-isope01/isope-i-01-140/8032 https://www.ptil.no/contentassets/bad77066a9ff4142bed4a9a3bdef314c/internal-integrity-management-of-rigid-flowlines---revision-3.pdf https://www.ptil.no/contentassets/bad77066a9ff4142bed4a9a3bdef314c/internal-integrity-management-of-rigid-flowlines---revision-3.pdf https://www.ptil.no/contentassets/bad77066a9ff4142bed4a9a3bdef314c/internal-integrity-management-of-rigid-flowlines---revision-3.pdf https://www.sciencedirect.com/science/article/pii/s1875510015001766 https://www.sciencedirect.com/science/article/pii/s1875510015001766 https://www.sciencedirect.com/science/article/pii/s1875510015001766 https://www.sciencedirect.com/science/article/pii/s1875510015001766 https://www.sciencedirect.com/science/article/pii/s1875510015001766 https://papers.ssrn.com/sol3/delivery.cfm?abstractid=2394642#page=42 https://papers.ssrn.com/sol3/delivery.cfm?abstractid=2394642#page=42 https://papers.ssrn.com/sol3/delivery.cfm?abstractid=2394642#page=42 https://papers.ssrn.com/sol3/delivery.cfm?abstractid=2394642#page=42 https://papers.ssrn.com/sol3/delivery.cfm?abstractid=2394642#page=42 https://onepetro.org/speuhse/proceedings-abstract/13hse/all-13hse/spe-164969-ms/177901 https://onepetro.org/speuhse/proceedings-abstract/13hse/all-13hse/spe-164969-ms/177901 https://onepetro.org/speuhse/proceedings-abstract/13hse/all-13hse/spe-164969-ms/177901 https://onepetro.org/speuhse/proceedings-abstract/13hse/all-13hse/spe-164969-ms/177901 https://onepetro.org/speuhse/proceedings-abstract/13hse/all-13hse/spe-164969-ms/177901 https://onepetro.org/speuhse/proceedings-abstract/13hse/all-13hse/spe-164969-ms/177901 https://onepetro.org/speofcs/proceedings-abstract/10ofcs/all-10ofcs/spe-130525-ms/109828 https://onepetro.org/speofcs/proceedings-abstract/10ofcs/all-10ofcs/spe-130525-ms/109828 https://onepetro.org/speofcs/proceedings-abstract/10ofcs/all-10ofcs/spe-130525-ms/109828 https://onepetro.org/speofcs/proceedings-abstract/10ofcs/all-10ofcs/spe-130525-ms/109828 https://onepetro.org/speofcs/proceedings-abstract/10ofcs/all-10ofcs/spe-130525-ms/109828 https://onepetro.org/isopeiopec/proceedings-abstract/isope14/all-isope14/isope-i-14-482/14210 https://onepetro.org/isopeiopec/proceedings-abstract/isope14/all-isope14/isope-i-14-482/14210 https://onepetro.org/isopeiopec/proceedings-abstract/isope14/all-isope14/isope-i-14-482/14210 https://onepetro.org/isopeiopec/proceedings-abstract/isope14/all-isope14/isope-i-14-482/14210 https://onepetro.org/spehse/proceedings-abstract/08hse/all-08hse/spe-111604-ms/144754 https://onepetro.org/spehse/proceedings-abstract/08hse/all-08hse/spe-111604-ms/144754 https://onepetro.org/spehse/proceedings-abstract/08hse/all-08hse/spe-111604-ms/144754 https://onepetro.org/spehse/proceedings-abstract/08hse/all-08hse/spe-111604-ms/144754 https://onepetro.org/spehse/proceedings-abstract/08hse/all-08hse/spe-111604-ms/144754 https://onepetro.org/spehse/proceedings-abstract/08hse/all-08hse/spe-111604-ms/144754 https://onepetro.org/speaphs/proceedings-abstract/07aphs/all-07aphs/spe-108853-ms/142629 https://onepetro.org/speaphs/proceedings-abstract/07aphs/all-07aphs/spe-108853-ms/142629 https://onepetro.org/speaphs/proceedings-abstract/07aphs/all-07aphs/spe-108853-ms/142629 https://onepetro.org/spehse/proceedings-abstract/20hse/3-20hse/d032s003r001/447132 https://onepetro.org/spehse/proceedings-abstract/20hse/3-20hse/d032s003r001/447132 https://onepetro.org/spehse/proceedings-abstract/20hse/3-20hse/d032s003r001/447132 https://onepetro.org/spehse/proceedings-abstract/20hse/3-20hse/d032s003r001/447132 https://onepetro.org/spehse/proceedings-abstract/20hse/3-20hse/d032s003r001/447132 https://onepetro.org/spehse/proceedings-abstract/20hse/3-20hse/d032s003r001/447132 https://onepetro.org/spehse/proceedings-abstract/00hse/all-00hse/spe-62485-ms/131799 https://onepetro.org/spehse/proceedings-abstract/00hse/all-00hse/spe-62485-ms/131799 https://onepetro.org/spehse/proceedings-abstract/00hse/all-00hse/spe-62485-ms/131799 https://onepetro.org/spehse/proceedings-abstract/00hse/all-00hse/spe-62485-ms/131799 https://onepetro.org/spehse/proceedings-abstract/00hse/all-00hse/spe-62485-ms/131799 https://onepetro.org/spehse/proceedings-abstract/96hse/all-96hse/spe-35777-ms/58257 https://onepetro.org/spehse/proceedings-abstract/96hse/all-96hse/spe-35777-ms/58257 https://onepetro.org/spehse/proceedings-abstract/96hse/all-96hse/spe-35777-ms/58257 https://onepetro.org/spehse/proceedings-abstract/96hse/all-96hse/spe-35777-ms/58257 https://www.earthdoc.org/content/papers/10.3997/2214-4609-pdb.280.iptc14946_nopw https://www.earthdoc.org/content/papers/10.3997/2214-4609-pdb.280.iptc14946_nopw https://www.earthdoc.org/content/papers/10.3997/2214-4609-pdb.280.iptc14946_nopw https://www.earthdoc.org/content/papers/10.3997/2214-4609-pdb.280.iptc14946_nopw https://onepetro.org/cmtconf/proceedings-abstract/12cmtc/all-12cmtc/cmtc-151144-ms/591 https://onepetro.org/cmtconf/proceedings-abstract/12cmtc/all-12cmtc/cmtc-151144-ms/591 https://onepetro.org/cmtconf/proceedings-abstract/12cmtc/all-12cmtc/cmtc-151144-ms/591 https://onepetro.org/cmtconf/proceedings-abstract/12cmtc/all-12cmtc/cmtc-151144-ms/591 https://onepetro.org/spenaic/proceedings-abstract/18naic/all-18naic/spe-193429-ms/215732 https://onepetro.org/spenaic/proceedings-abstract/18naic/all-18naic/spe-193429-ms/215732 https://onepetro.org/spenaic/proceedings-abstract/18naic/all-18naic/spe-193429-ms/215732 https://onepetro.org/spenaic/proceedings-abstract/18naic/all-18naic/spe-193429-ms/215732 https://onepetro.org/spenaic/proceedings-abstract/18naic/all-18naic/spe-193429-ms/215732 https://onepetro.org/spenaic/proceedings-abstract/18naic/all-18naic/spe-193429-ms/215732 https://onepetro.org/speadip/proceedings-abstract/14adip/3-14adip/d031s059r004/210227 https://onepetro.org/speadip/proceedings-abstract/14adip/3-14adip/d031s059r004/210227 https://onepetro.org/speadip/proceedings-abstract/14adip/3-14adip/d031s059r004/210227 https://onepetro.org/speadip/proceedings-abstract/14adip/3-14adip/d031s059r004/210227 https://onepetro.org/speadip/proceedings-abstract/14adip/3-14adip/d031s059r004/210227 https://onepetro.org/speadip/proceedings-abstract/14adip/3-14adip/d031s059r004/210227 f. m. shaker and d. j. sadeq / iraqi journal of chemical and petroleum engineering 23,3 (2022) 67 73 73 القائم على المخاطر بسبب عواقب التآكل لخطوط تدفق النفط والغاز: مراجعة فحصال ضفاف جعفر صادق 2، فاطمة محمود شاكر 1 ، العراقشركة نفط البصره ،حقل الرميلة النفطي 1 قسم هندسة البترول ، جامعة بغداد ، العراق 2 الخالصة مكانيات إن صناعة البترول ، التي تعد إحدى ركائز االقتصاد الوطني ، لديها القدرة على توليد ثروة هائلة وا عمل. يعتبر نقل المنتجات البترولية أمًرا معقًدا وقابل للتغيير بسبب المخاطر الناجمة عن عواقب التآكل. قد رث الطبيعية إلى اإلضرار بالبيئة ، مما يؤدي إلى خسائر تؤدي التسريبات الكيميائية الخطرة التي تسببها الكوا اقتصادية كبيرة. إنه يهدد بشكل كبير هدف التنمية المستدامة. عند نتيجة ذلك ، يصبح تحديد احتمالية التسرب واحتمالية حدوث ضرر بيئي أولوية قصوى لصانعي القرار أثناء قيامهم بتطوير خطط الصيانة. تحاول هذه وفير فهم شامل للمخاطر المرتبطة بخطوط تدفق النفط والغاز. كما يحاول تحديد عوامل الخطر الدراسة ت األساسية في المشاريع االنسيابية ، باإلضافة إلى احتمالية حدوثها وخطورتها ، من أجل تقليل الخسائر في دي لتحديد الخسائر البيئية الناجمة األرواح وزيادة النفقات نتيجة لقضايا السالمة. تم استخدام التقدير الكمي النق ، تم تقييم مستوى المخاطر البيئية.والفحص القائم على 5× 5عن التسرب. باستخدام مصفوفة احتمالية المخاطر من خالل استخدام جداول معينه لتتحديد احتمالية الفشل والعاقبه يظهر مستوى المخاطر في المصفوفة سبة لتقليل المخاطركحقن مثبطات التاكل او تفعيل الحمايه الكاثوديه او ، ويجب القيام بخطوات صيانة منا تغليف االنبوب . بشكل عام ، يساهم هذا البحث في منع تسرب المنتجات البترولية نتيجة التآكل في قطاع .النقل. أيًضا ، شجع متخذي القرارات غير البيئية على اكتساب فهم أفضل لمستوى المخاطر تسرب النفط ،الفحص على اساس المخاطر ، احتمال الفشل، نتيجة الفشل ة: الدالالكلمات iraqi journal of chemical and petroleum engineering vol.13 no.2 (june 2012) 19 issn: 1997-4884 phenyl thiourea as corrosion inhibitor for mild steel in strong hydrochloric acid aprael s. yaro and dhuha a. abdulaaima department of chemical engineering, college of engineering, university of baghdad, iraq abstract the inhibitive action of phenyl thiourea (ptu) on the corrosion of mild steel in strong hydrochloric acid, hcl, has been investigated by weight loss and potentiostatic polarization. the effect of ptu concentration, hcl concentration, and temperature on corrosion rate of mild steel were verified using 2 levels factorial design and surface response analysis through weight loss approach, while the electrochemical measurements were used to study the behavior of mild steel in 5-7n hcl at temperatures 30, 40 and 50 °c, in absence and presence of ptu. it was verified that all variables and their interaction were statistically significant. the adsorption of (ptu) is found to obey the langmuir adsorption isotherm. the effect of temperature on the adsorption process showed that the adsorption process is exothermic, spontaneous and represents mixed chemical and physical adsorption for ptu on the metal surface. key words corrosion, phenyl thiourea, electrochemical measurements, dimensionless separation factor, factorial design, adsorption, activation parameters introduction the corrosion of metals remains a world -wide scientific problem as it affects the metallurgical, chemical, and oil industries [1]. hydrochloric acid is widely used for the removal of the rust and scale in several industrial operations [2]. when mild steel is used in these operations it suffers sever corrosion [3]. using inhibitors is one of the most practical methods for protection against corrosion, especially in acid solutions, to prevent metal dissolution and acid consumption [4]. organic compounds containing n and s have proved to be good inhibitors for the preventation of corrosion under acidic conditions [5]; therefore, thiourea and its derivatives have been extensively investigated as corrosion inhibitors in acidic media [6]. the main objective of this investigation is to study the inhibitive effect of phenyl thiourea (ptu) for the mild steel corrosion in strong hydrochloric acid using weight loss and potentiostatic methods. experimental method a mild steel sheet was used as working electrode of 20 mm (width), 30 mm (length) and 1 mm thickness in weight loss method. area of (0.8 cm²) was used for polarization method. its composition is :( c=0.17-0.2, mn<1.4, s<0.045, p< 0.045, fe reminder). (5 iraqi journal of chemical and petroleum engineering university of baghdad college of engineering phenyl thiourea as corrosion inhibitor for mild steel in strong hydrochloric acid 2 ijcpe vol.13 no.2 (june 2012) -available online at: www.iasj.net and 7 n) hydrochloric acid solutions were prepared using distilled water. weight loss method the specimens were polished with emery papers and then cleaned with tap water, distilled water, benzene and acetone. after that they were dried and weighed on a digital scale. each of the specimens is designated and its initial weight is noted. after each test, the specimen was washed with running tap water, scrubbed with a brush to remove corrosion products, then washed with tap water followed by distilled water and dried on clean tissue, immersed in benzene, dried, immersed in acetone, dried and left in a desiccators over silica gel for 1 hour before weighting. the time of immersion in hcl solutions was two hours. polarization techneque by using a wenking m lab potentiostat and a three electrode cell, electrochemical studies were performed. platinum over titanium (pt/ti) electrode was used as the auxiliary electrode and a saturated silver electrode ag/agcl as the reference electrode. the corrosion rates are determined by tafel extrapolation technique. the experiments were conducted at 30, 40, and 50 °c. results and discussions weight loss method table (1) represents the low and high levels factor, the matrix of the factorial design. table 1, factors and levels used in 2³ factorial design variables low level (-1) high level (+1) inhibitor concentration (ppm) 100 1000 acid concentration (n) 5 7 temperature (˚c) 30 70 table (2) shows the experimental results. table 2, effect of hcl concentration, ptu concentration, and temperature on corrosion rate of mild steel table (3) shows the main effects of the factors under study and their interaction on the corrosion rate of mild steel in hcl acid media in presence of phenyl thiourea (ptu). table 3, the variables effect and their interaction using ptu factor main effect or interaction x₁ -7282.25 x₂ 3443.25 x₃ 10478.75 x₁ x₂ -998.75 x₁ x₃ -6818.25 x₂ x₃ 2860.25 it is clear from table (3) that the acid concentration and the temperature accelerate corrosion, and the effect of temperature is about 4 times larger than acid concentration. the inhibitor, on the other hand, decreases the corrosion rate sharply under the operating conditions. yates method [7] was followed on the data which are given in table (3). a mathematical expression to describe the design matrix combination mentioned in table (2) as low and high level of each factor and its corresponding corrosion rates mentioned in table (3) in code values were obtained as follows: no. ptu (ppm) x₁ hcl (n) x₂ temperatur e (˚c) x₃ corrosion rate g/m².day 1 100 5 30 135 2 100 5 70 13970 3 100 7 30 1115 4 100 7 70 21874 5 1000 5 30 68 6 1000 5 70 1470 7 1000 7 30 254 8 1000 7 70 6173 aprael s. yaro and dhuha a. abdulaaima -available online at: www.iasj.net ijcpe vol.13 no.2 (june 2012) 3 y=5632.3753641.125x₁+1721.625x₂+5239.375x₃ +1430.125x₂x₃-499.375x₁x₂3409.125x₁x₃ …(1) where: y is the corrosion rate at each variable combination. x₁, x₂, x₃ are inhibitor concentration, acid concentration, and temperature, respectively. the results were analyzed using the analysis of variance (anova) as appropriate to experimental design used. from anova, the variables and their interaction effect on the corrosion rate were significant. polarization technique the polarization curves in the absence and the presence of ptu in (7 n hcl solutions) at different temperatures are presented in figures 1 through 12, respectively. table (4) shows the values of corrosion parameters obtained using tafel extrapolation method. fig.1, polarization behavior of mild steel in 7n hcl in absence of ptu at temperature =30˚c fig.2, polarization behavior of mild steel in 7n hcl in presence of 100 ppm of ptu at temperature =30˚c fig. 3, polarization behavior of mild steel in 7n hcl in presence of 550 ppm of ptu at temperature =30˚c fig. 4, polarization behavior of mild steel in 7n hcl in presence of 1000 ppm of ptu at temperature =30˚ c fig. 5, polarization behavior of mild steel in 7n hcl in absence of ptu at temperature =40˚c fig. 6, polarization behavior of mild steel in 7n hcl in presence of 100 ppm of ptu at temperature =40˚c phenyl thiourea as corrosion inhibitor for mild steel in strong hydrochloric acid 4 ijcpe vol.13 no.2 (june 2012) -available online at: www.iasj.net fig. 7, polarization behavior of mild steel in 7n hcl in presence of 550 ppm of ptu at temperature =40˚ fig. 8, polarization behavior of mild steel in 7n hcl in presence of 1000 ppm of ptu at temperature =40˚ c fig. 9, polarization behavior of mild steel in7n hcl in absence of ptu at temperature =50˚c fig. 10, polarization behavior of mild steel in 7n hcl in presence of 100 ppm of ptu at temperature =50˚c fig. 11, polarization behavior of mild steel in 7n hcl in presence of 550 ppm of ptu at temperature =50˚c fig. 12, polarization behavior of mild steel in 7n hcl in presence of 1000 ppm of ptu at temperature = 50°c table 4, corrosion parameters obtained for mild steel in 7n hcl at different temperatures and concentrations of ptu effect of temperature and activation studies activation energy, eact., activation entropy, δsact., and enthalpy of activation, δhact. were calculated using arrhenius equation: ptu ppm temp k ecorr mv icorr μa/cm² ba mv/dec -bc mv/dec ie (%) nil 303 -365 2380 76 124 ...... 313 -364 7190 69 139 ...... 323 -392 9840 83 79 ...... 100 303 -437 372 54 183 84.4 313 -420 1440 74 106 80 323 -453 935 55 147 90.5 550 303 -404 222 56 78 90.7 313 -438 1240 60 129 82.8 323 -441 2180 67 144 77.8 1000 303 -440 305 53 137 87.2 313 -424 440 61 125 94 323 -445 1940 72 173 80.3 aprael s. yaro and dhuha a. abdulaaima -available online at: www.iasj.net ijcpe vol.13 no.2 (june 2012) 5 log icorr = log a eact/2.303 rt …(2) and its alternative formulation called transition state equation: icorr = (rt/nh) exp(δsact./r) exp(δhact./rt) …(3) where, t is the absolute temperature, r, the universal gas constant, h is planck´s constant, and n is avogadro´s number. from the corrosion current densities obtained from polarization curves at different temperatures in the absence and the presence of ptu as corrosion inhibitor, arrhenius plots are shown in figure 13 for a temperature range of (303-323 k) in 7n acid concentration. the activation energies calculated from arrhenius plots, and the values of δsact. and the δhact. obtained from transition state plots with accepted regression coefficient are listed in table (5). figure (14) shows transition state plots for temperature range of (303323 k) in 7n acid concentration. table 5, activation parameters for adsorption of ptu on mild steel at different conditions from table (5), it is observed that the activation energy, eact., and activation enthalpy, ∆hact., for uninhibited acid were lower than in inhibited acid. the higher values in the presence of ptu inhibitor indicate physical adsorption of the inhibitor on the metal surface. the results showed the positive sign for both eact. and ∆hact., reflecting the endothermic nature of corrosion process [4]. the endothermic process is attributed to chemisorptions. all values of eact. are larger than the analogous values of ∆hact indicating that the corrosion process must involve a gaseous reaction, simply the hydrogen evolution reaction, associated with a decrease in total reaction volume [8]. fig.13, arrhenius plot of mild steel in 7 n hcl contains different concentrations of ptu at different temperatures fig.14, transition state plot of mild steel in 7 n hcl contains different concentrations of ptu at different temperatures the negative values of ∆sact. pointed to a greater order produced during the process of activation. this can be achieved by the formation of activated complex and represents association or fixation with consequent loss in the degrees of freedom of the system ptu ppm eact. kj/mol r² δhact. kj/mol δsact. j/mol. k r² nil 56.52 0.9 17 54.15 -0.919 0.914 100 56.59 0.9 38 54.26 -16.05 0.901 550 90.91 0.9 36 88.17 92.14 0.932 1000 72.63 0.8 73 70.08 32.21 o.867 phenyl thiourea as corrosion inhibitor for mild steel in strong hydrochloric acid 6 ijcpe vol.13 no.2 (june 2012) -available online at: www.iasj.net during the process [9]. it means that a decrease in disordering take place on going from reactants to the activated complex [10, 11]. the increase of ∆sact. reveals that an increase in disordering take place from reactant to activated complex [12]. adsorption isotherm studies figure (15) shows the linear plots for c/ѳ versus c, suggesting that the adsorption obeys the langmuire´s isotherm: c/ѳ = 1/kads + c …(4) where c is the inhibitor concentration, and kads the adsorptive equilibrium constant, representing the degree of adsorption (i.e., the higher value of kads indicates that the inhibitor is strongly adsorped on the metal surface); the value of kads obtained from the reciprocal of intercept of langmuir´s plot lines and the slop of these lines is near unity, which mean that each inhibitor molecule occupies one active site on the metal surface. moreover, the essential characteristic langmuir isotherm can be expressed in terms of a dimensionless separation factor, rl [4], which describes the type of isotherm and is defined by: r = ads c …(5) the smaller rl value indicates a highly favorable adsorption. if rl >1, unfavorable; rl=1, linear; 0< rl<1, favorable; and if rl=0, irreversible. table (6) gives the estimated values of rl for ptu in 7n hcl at different temperature. it was found that all rl values are less than unity, confirming that the adsorption is favorable. fig.15, langmuir adsorption isotherm of ptu on mild steel in7n hcl at different temperatures the standard adsorption free energy (∆gads°) was calculated using the following equation [13]: kads = (1/55.5) exp (-∆g ° ads/rt) …(6) where, 55.5 is the concentration of water in solution expressed in molar, r is the gas constant, and t is the absolute temperature. the average value of standard adsorption free energy is ∆gads=-25.769 kj/mol. the negative values of ∆gads ensure the spontaneity of the adsorption process and stability of the adsorbed layer on the metal surface. generally, values of ∆gads up to -20 kj/mol are consistent with electrostatic interaction between the charged molecule and the charged metal (physisorption), while those around -40 kj/mol or higher are associated with chemisorptions as a result of sharing or transfer of electrons from the organic molecules to the metal surface to form a coordinate type of bond [14]. while other researchers suggested that the range of ∆gads of chemical adsorption processes for organic inhibitor in aqueous media lies between -21 to -42 kj/ mol [15]. therefore, for the present work the value of ∆gads is larger than the common physical adsorption values, but smaller than the common chemical aprael s. yaro and dhuha a. abdulaaima -available online at: www.iasj.net ijcpe vol.13 no.2 (june 2012) 7 adsorption values [16], probably meaning that both physical and chemical adsorption take place (i.e. comprehensive adsorption). the dependence of ∆gads on temperature can be explained by two cases as follows [17]: 1. ∆gads may increase (becomes less negative) with the increase in temperature which indicates the occurrence of exothermic process. 2. ∆gads may decrease (becomes more negative) with the increase in temperature which indicates the occurrence of endothermic process. table 6, dimensionless separation factor rl for ptu at various temperatures temp (k) ptu (g/l) rl 303 0.1 0.218 0.55 0.04 1 0.027 313 0.1 0.253 0.55 0.058 1 0.0328 323 0.1 0.555 0.55 0.185 1 0.111 values of other thermodynamic parameters such as enthalpy (∆hads) and entropy (∆sads) can provide supplementary information about the mechanism of corrosion inhibition. the enthalpy (∆hads) and entropy (∆sads) of adsorption on mild steel in hydrochloric acid in the presence of inhibitor can be calculated by using the following equation [18]: ln kads = ln( /55.5) ∆sads/r-∆hads/rt …(7) using equation (7), the values of enthalpy (∆hads) and entropy (∆sads) of adsorption were evaluated from the slope and intercept of the plot of ln kads versus 1/t as shown in figure (16). the thermodynamic data of adsorption are depicted in table (7). fig.16, plot of ln kads against 1/t for ptu on mild steel in 7n hcl at different temperatures table 7, thermodynamic parameters for adsorption of ptu on mild steel surface in 7n hcl at different temperatures temp (k) kads l/g slope ∆gads kj/mol ∆hads kj/mol ∆sads j/mol.k 303 35.71 1.100 -26.406 -58.74 -105.03 313 29.41 1.056 -26.773 323 8 1.096 -24.13 the values obtained confirm the exothermic behavior of the adsorption process of ptu on mild steel surface in hydrochloric acid. while an endothermic adsorption process (∆hads>0) is attributed unequivocally to chemisorptions, an exothermic adsorption process (∆hads <0) may involve either physisorption or chemisorption or a mixture of both processes [19, 20]. in the present work, the value obtained may introduce physisorption and chemisorption processes which are confirmed by previous discussion. also, the negative values of ∆hads show that the adsorption is exothermal with an ordered phenomenon ascribed by the negative values of ∆sads. this order may more probably be explained by the possibility of formation of iron complex on the metal surface [21, 22], or inhibitor molecules may freely move in the bulk of solution before the adsorption process, while with progress in adsorption the inhibitor molecules were orderly adsorbed on the metal surface, which resulted in the decrease in entropy[16]. 1 1.5 2 2.5 3 3.5 4 0.003050.00310.003150.00320.003250.00330.00335 ln k a d s( l/ g ) 1⁄t (k¯¹) phenyl thiourea as corrosion inhibitor for mild steel in strong hydrochloric acid 8 ijcpe vol.13 no.2 (june 2012) -available online at: www.iasj.net conclusions 1. phenyl thiourea (ptu) represents effective inhibitor in 7n hcl at temperature range of 30 -50°c. the maximum inhibition efficiency was found to be 94% at 40°c and 1000 ppm of ptu. 2. the endothermic nature and chemisorption of corrosion process. 3. the adsorption of ptu is spontaneous and exothermic and follows langmuir adsorption isotherm. 4. the adsorption of ptu is comprehensive (physical and chemical adsorption) for the inhibition process. acknowledgments the authors would like to express all their thanks to allah, who enabled them to overcome all the difficulties associated with this study till producing this project in its final form. they would also like to thank prdc petroleum research and development center (contract monitor: d. shehab) for the financial support of this project. references 1. a. o. james, n. c. oforka, olusegum . abiola, “inhibition of acid corrosion of mild steel by pyridoxal and pyridoxal hydrochloride”, electrochem. sci., 2(2007) 278-284. 2. g.y. elewady, “pyrimidine derivatives as corrosion inhibitors for carbon-steel in 2m hydrochloric acid solution”, electrochem. sci., 3 (2008) 1149 – 1161. 3. p. bothi raja and m.g. sethuraman, “studies on the inhibition of mild steel corrosion by rauvolfia serpentina in acid media” ,journal of materials engineering and performance, 19(5) 2010 761-766. 4. a. a. khadom, a. s. yaro, a. s. altaie, a. a. h. kadum, “electrochemical, activations and adsorption studies for the corrosion inhibition of low carbon steel in acidic media”, port. electrochem. acta., 27(6),2009, 699-712. 5. archana gupta and m.m. singh, “inhibition of mild steel corrosion in formic acid by thiourea, 2amino [4-p-chloro phenyl] thiazole and different derivatives of their condensation products”, port. electrochem. acta. 17 (1999) 2143. 6. s.d.setty,p.shetty and h.v. s. nayak, “inhibition of mild steel in hcl acid by n-cyclohexyl-n phenyl thiourea”, indian journal of chemical technology,12(2005)462 465. 7. davis, o. ., “design and analysis of industrial experimentation”, hafiner publishing co. new york, n. y. (1960). 8. e. a. noor, “temperature effect on corrosion inhibition of mild steel in acidic solution by aqueous extract of fenugreek leaves”, electrochem. sci., 2(2007) 996-1017. 9. e. a. noor, “evaluation of inhibitive action of some quaternary n heterocyclic compounds on the corrosion of al–cu alloy in hydrochloric acid”, mater. chem. phys. 114 (2009) 533–541. 10. s. s. abd el-rehim, h. h. hassan and m. a. amin, “corrosion inhibition of aluminum by 1,1(lauryl amido)propyl ammonium chloride in hcl solution”, mater. chem. phys.70 (2001) 64-72. 11. g. k. gomma and m. h. wahdan, “schiff bases as corrosion inhibitors for aluminum in hydrochloric acid solution”, mater. chem. phys. 39 (1995) 209-213. 12. i. naqvi , a. r. saleemi, s. naveed, “cefixime: a drug as aprael s. yaro and dhuha a. abdulaaima -available online at: www.iasj.net ijcpe vol.13 no.2 (june 2012) 9 efficient corrosion inhibitor for mild steel in acidic media electrochemical and thermodynamic studies”, electrochem. sci., 6 (2011) 146 – 161. 13. s.a. umoren, e.e. ebenso, “the synergistic effect of polyacrylamide and iodide ions on the corrosion inhibition of mild steel in h2so4”, mater. chem. phys., 106 (2007) 387-393. 14. s.a. umoren, i.b. obot, e.e. ebenso, “corrosion inhibition of aluminum using exudate gum from pachylobus edulis in the presence of halide ions in hcl”, e-journal chem., 5 (2008) 355-364. 15. w.w. damaskin, o.a. pietrij, w.w. batrakow, “adsorption of organic compounds on electrode”, plenum press”, new york, 97 . 16. g. mu, x. i, g. iu, “synergistic inhibition between tween 60 and nacl on the corrosion of cold rolled steel in 0.5 m sulfuric acid”, corros. sci., 47(2005) 1932-1952. 17. . tang, g. mu, g. iu, “the effect of neutral red on the corrosion inhibition of cold rolled steel in .0 m hydrochloric acid”, corros. sci., 45 (2003) 2251-2262. 18. b. a. mohammed, k. n. mohana, “the effect of sodium benzoate and sodium 4-(phenylamino) benzenesulfonate on the corrosion behavior of low carbon steel”, monatsh chem/chemical monthly, 140 (2009) 1–8. 19. w. durnie, r.d. marco, a. jefferson, b. kinsella, “development of a structureactivity relationship for oil field corrosion inhibitors”, j. electrochem. soc., 146 (1999) 1751-1756. 20. s.a. ali, a.m. el-shareef, r.f. al-ghamdi, m.t. saeed, “ the isoxazolidines: the effects of steric factor and hydrophobic chain length on the corrosion inhibition of mild steel in acidic medium”, corros. sci., 47 (2005) 2659-2678. 21. m. abdallah and m.m. el-naggar, “cu 2 cation 3, 5-dimethyl pyrazole mixture as a corrosion inhibitor for carbon steel in sulfuric acid solution”, mater. chem. phys., 71 (2001) 291-298. 22. a. bousseksou, g. molnár, j.a. real, k. tanaka, “spin crossover and photomagnetism in dinuclear iron (ii) compounds”, coord. chem. rev., 251 (2007) 1822-1833. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.23 no.1 (march 2022) 31 – 41 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: rasha h. salman, email: rasha.habeeb@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. study the optimization of petroleum refinery wastewater treatment by successive electrocoagulation and electrooxidation systems hind m. ibrahim and rasha h. salman chemical engineering department – college of engineering – university of baghdad abstract in this study, successive electrocoagulation (ec) and electro-oxidation (eo) processes were used to minimize some of the major pollutants in real wastewater, such as organics (detected by chemical oxygen demand (cod)), and turbidity. the wastewater utilized in the present study was collected from the midland refinery company in baghdad-iraq. the performance of the successive batch ec-eo processes was studied by utilizing graphite and aluminum (al) as monopolar anode electrodes and stainless steel (st.st.) as the cathode. the taguchi experimental design approach was used to attain the best experimental conditions for cod reduction as a major response. starting from chemical oxygen demand cod of (600 ppm), the effects of current density (c.d.) (1020 ma/cm2), ph (410), time (2– 4 h), and nacl concentration (1.52.5 g/l) on the efficiency of cod reduction were examined. the results indicated that cod reduction increased with increasing c.d., nacl conc., and electrolysis time and increased exponentially at ph (4). the best conditions for the treatment of this wastewater were: c.d. (20 ma/cm 2 ), ph (4), time (4 h), and nacl conc. (2.5 g/l). at these conditions, approximately 98.12 % of cod reduction was achieved with electrical energy consumption (enc) of about 62.04 kwh/m 3 . the result of analysis of variance (anova) revealed that the c.d. and ph have a higher influence on the performance of organics removal, while the time and nacl conc. have a minor impact on cod re%. keywords: petroleum, refinery wastewater, electrocoagulation, electro-oxidation, successive, taguchi method received on 19/02/2022, accepted on 08/03/2022, published on 30/03/2022 https://doi.org/10.31699/ijcpe.2022.1.5 1introduction water is required for the life on planet earth as a basic element. today, the aquatic environment is severely contaminated and the natural watercourses have been severely destroyed [1]. petroleum oil is a significant component of the world's energy supply, and huge quantities of wastewater are produced throughout the oil refining process, with significant organic pollutants, severe toxicity, and poor biodegradability [2]. petroleum wastewater is considered as a substantial polluting source, generally characterized by the high chemical oxygen demand (cod) and salinity and there are various quantities of emulsified oil, heavy metals, and organic contaminants, in addition to oil and grease (o&g) [3]. several techniques were employed for the treatment of refinery wastewater such as adsorption [4], ion-exchange [5], biosorption [6], membrane filtration [7], coagulationflocculation [8], electro-oxidation [9], and electrocoagulation [10]. in comparison to the conventional methods mentioned previously, electrochemical technology makes a significant contribution in protecting the environment by introducing effluent treatment and reducing waste and harmful chemicals [11]. due to its unique qualities, such as flexibility, energy economy, automation, and cost effectiveness, electrochemical treatment has received more attention in recent years [12]. one of the major electrochemical technologies is ec which possesses several advantages such as easy operation, short treatment time and no chemical requirement. ec has been lauded as a straightforward, efficient, and cost-effective method [13, 14]. in this process, the metal (m) is oxidized to its cation (m n+ ) when an external power source is delivered to it as potential. simultaneously, h2 and the hydroxyl ion (oh ) are produced via the reduction process of h2o. the generated metal ions would rapidly hydrolyze to polymeric metal hydroxide that operated as coagulation agents. tiny hydrogen bubbles form at the cathode and oxygen forms at the anode. due to the presence of these bubbles, the emulsified oil droplets get free of the water molecules that they were previously linked to, and they float to the surface where they can be seen [14, 15, 16]. the following reactions occur during the process at the anode when an aluminum anode is used [17, 18]: 𝐴𝑙→ 𝐴𝑙3++3𝑒− (1) http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:rasha.habeeb@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2022.1.5 h. m. ibrahim and r. h. salman / iraqi journal of chemical and petroleum engineering 23,1 (2022) 31 41 32 2𝐻2𝑂 → 4𝐻 + + 𝑂2 + 4𝑒 − (2) 𝑥 𝐴𝑙+3 + 𝑦 𝑂𝐻− → 𝐴𝑙𝑥 + (𝑂𝐻)𝑦 𝑧+ (3) while, the cathodic reactions for aluminum can be summarized as follows [17, 18]: 2𝐻2𝑂 + 2𝑒 − → 𝐻2 (𝑔) + 2𝑂𝐻 − (4) because of its simplicity and durability in construction and operation, electrochemical oxidation has received considerable scientific attention. organic contaminants can be destroyed in the eo method by either direct or indirect oxidation. in direct anodic oxidation, contaminants are adsorbed on the surface of the electrode and subsequently removed via the anodic electron transfer reaction that takes place in this oxidation process. while in the indirect eo process, strong oxidants such as hypochlorite/chlorine, hydrogen peroxide, and ozone are electrochemically generated. the contaminants are subsequently destroyed from the bulk solution via an oxidation process involving the generated oxidants [19, 20, 21]. main reactions in eo process at the anode, cathode, and in bulk solution in case of nacl addition may be shown as follows [22]: at anode: 2𝐶𝑙−→𝐶𝑙2+2𝑒 − (5) at cathode: 2𝐻2𝑂+2𝑒 − →2𝑂𝐻−+𝐻2 (6) at bulk solution: 𝐶𝑙2 + 𝐻2𝑂→ 𝐻𝑂𝐶𝑙 + 𝐻 + + 𝐶𝑙− ↔ 𝑂𝐶𝑙− + 𝐶𝑙− + 2𝐻+ (7) the primary objective of the present study is to evaluate the feasibility of using ec and eo methods in handling real wastewater from the midland refinery company in baghdadiraq. the study typically focuses on investigating and optimizing the effects of main parameters (c.d., time, ph, and nacl conc.) on the efficiency of ec and eo processes successively by taguchi experimental design with l18 orthogonal array. 2experimental work 2.1. chemicals and apparatus wastewater samples in the current study were collected from the feeding tank to the treatment unit from the midland refinery company in baghdad-iraq. the main characteristics of this wastewater were attained from the laboratories division (midland refinery company) at water pollution control unit laboratory; which were as follows: (cod= 600 ppm, total dissolved solids (tds)=1479 ppm, turbidity= 315 ntu, chlorides (cl)= 536 ppm, ph= 7.6). hydrochloric acid (hcl, 37%, liquid, sigma-aldrich) and sodium hydroxide (naoh, ≥ 97%, pellets, sigmaaldrich) were used to prepare a 1 m solution for adjusting the initial ph of the treated wastewater; and 1.5 or 2.5 g/l of sodium chloride (nacl powder, 99.5 % by weight, fisher chemicals (usa)) was added to the electrolytic solution which was utilized as the supporting electrolyte. 2.2. electrolytic cell the electrolytic cell was comprised of a laboratory dc digital power supply (type jyd aps, model: 3005d) with outlet voltage of 0-30 v and output current of 0-5 a, and the current that was supplied to each anode was measured with the use of two (pro’s kit, mt-1233c) multimeter connected to anodic lines. also, a digital ph meter (hanna instrument inc., model hi98107 phep, romania) was utilized to measure the ph of the solution during the experiments. the batch electrochemical reactor was a glass container with [17 cm (width), 13.5 cm (depth), and 17 cm (length)] and the electrolyte volume was 2 l. in ec process, the anode electrodes were two al plates and the cathode electrodes were three st. st. plates of type 316-aisi. while in the eo process, the anode electrodes were two graphite plates and the cathode electrodes were the same three st. st. plates of type 316-aisi. each anode was sandwiched between two cathodes. the distance between any two electrodes was 2 cm. the total dimensions of the graphite and al plates were [12.5 cm (width), 13 cm (length), and 0.23 cm (thickness)]. the dimensions of each st. st. plate were (12.5 cm x 12.5 cm). the effective surface area of anodes is 235 cm 2 (4.7 cm width 12.5 cm height for each anode electrode), which were dipped in the electrolyte. the electrolytic reactor was placed on a magnetic stirrer hot plate (heidolph™ 505-20000-00, 0-300°c; 0-1400 rpm) for obtaining a homogeneous solution at a rotation speed of 350 rpm. before each experiment all the electrodes must be reactivated, al electrodes were rinsed with a 5 percent (v/v) hcl solution for at least 10 minutes and st. st. electrodes were rinsed with hno3 solution (1m) in an ultrasound cleaner and then washed carefully with distilled water. the positive and negative portions of a dc power supply were connected to the anode (al in ec process, graphite in eo process) and cathodes (st.st.) respectively, and a multimeter was connected in series with the anode. many primarily experiments were conducted to assess the range of studied factors and to have an overview of the expected mechanism. so, based on the observations from these experiments the time for the ec process was taken like an hour and the remaining time for the eo process. in the first hour in any run in the set of ec-eo experiments, al electrodes were utilized as anodes in the ec process then they were replaced by graphite electrodes and the eo process employed for the remaining time. in each experiment, the applied current and associated voltages were recorded for each anode by a multimeter. h. m. ibrahim and r. h. salman / iraqi journal of chemical and petroleum engineering 23,1 (2022) 31 41 33 the samples were collected and then filtered with whatman filter paper and analyzed to conclude the performance of treatment (cod, ph measurement, turbidity measurement, and conductivity analysis). experiments were carried out at a temperature of (30± 1°c), and each experiment was duplicated the average value of cod was taken and set as the final result. 2.3. characterization and measurements the performance of the successive ec-eo process was examined by reduction efficiency of many characteristics, and the main characteristic in the present study was the cod that was measured by thermos-reactor (rd125, lovibond). two ml of initial and treated effluent for each experiment was taken and then added to vial containing an oxidizing agent and they were gently mixed. the vial was placed in the reactor and heated to a temperature of 150 °c for 120 minutes. the digested sample was cooled down to room temperature and then analyzed in a spectrophotometer (md200, lovibond germany photometers with photometric detection) to measure the cod concentration in mg/l. cod reduction efficiency can be expressed as in eq. (8) [23]: 𝐶𝑂𝐷 𝑅𝑒% = 𝐶𝑂𝐷𝑜− 𝐶𝑂𝐷𝑓 𝐶𝑂𝐷𝑜 × 100 (8) an optoelectronic meter (turbidirect lovibond, tb 300 ir, germany) was used to measure turbidity in each sample of treated effluent. this digital meter uses a synthetic light source that gives a known-intensity light to the sample. sample preparation for turbidity measurements is as simple as shaking the sample vial thoroughly before running the test. the value of turbidity reduction percentage can be obtained by eq. (9) [24]. 𝑡𝑢𝑟𝑏𝑖𝑑𝑖𝑡𝑦 𝑅𝑒% = 𝑡𝑢𝑟𝑏𝑖𝑑𝑖𝑡𝑦𝑜− 𝑡𝑢𝑟𝑏𝑖𝑑𝑖𝑡𝑦𝑓 𝑡𝑢𝑟𝑏𝑖𝑑𝑖𝑡𝑦𝑜 × 100 (9) a digital laboratory cond. meter (crison (ec-meter basic 30), spain) was used to measure the conductivity (cond.) of heavy metal salts. where: o and f were the initial and final values of each analysis respectively. the values of energy consumed for each experiment was determined by eq. (10) [25]: enc= (uc.i.t) ⁄ (v*1000) (10) 2.4 design of experiments by taguchi method the simplicity and efficiency of the taguchi approach are the main causes to utilize it for reducing time, cost, errors, and variation of any process. besides, the optimization of the factors can be accomplished with the smallest number of experiments [26, 27]. signal to noise (s/n) is a quantitative measurement utilized by taguchi's approach to find the optimal reduction conditions. also, it is utilized to evaluate variance around a response's mean value due to experimental noise, so an optimal response with lower variation may be achieved. mean (output characteristic) and standard deviation (output characteristic) are the terminology used to describe acceptable and undesirable values for the output response, respectively [28, 29, and 30]. an increase in the s/n ratio is often associated with an increase in noise. therefore, the best level of process parameters is the one with the largest s/n ratio [30, 31]. the main objective in the present study is to achieve the maximum value of cod reduction; thus, the hb (higher is best) s/n ratio analysis was applied. eq. (11) performs the s/n ratio with hb characteristic [32]: 𝑆 𝑁 = − log [ 1 𝑛 ∑ 1 𝑦𝑖 2 𝑛 𝑖=1 ] (11) the experimental results were assessed by minitab statistical software (version 17). the levels of the four chosen factors which were studied in the present study are shown in table 1. the suitable orthogonal array according to taguchi approach would be l18 either (3 3 × 2 1 ) that presented in table 2. table 1. selected experimental parameters and their assigned levels parameter coded level 1 level 2 level 3 nacl (g/l) x1 1.5 2.5 c.d (ma/cm 2 ) x2 10 15 20 ph x3 4 7 10 time (h) x4 2 3 4 table 2. coded and real values of l18 orthogonal array exp. no. coded values real values x1 x2 x3 x4 nacl (g/l) c.d. (ma/cm 2 ) ph time (h) 1 1 1 1 1 1.5 10 4 2 2 1 1 2 2 1.5 10 7 3 3 1 1 3 3 1.5 10 10 4 4 1 2 1 1 1.5 15 4 2 5 1 2 2 2 1.5 15 7 3 6 1 2 3 3 1.5 15 10 4 7 1 3 1 2 1.5 20 4 3 8 1 3 2 3 1.5 20 7 4 9 1 3 3 1 1.5 20 10 2 10 2 1 1 3 2.5 10 4 4 11 2 1 2 1 2.5 10 7 2 12 2 1 3 2 2.5 10 10 3 13 2 2 1 2 2.5 15 4 3 14 2 2 2 3 2.5 15 7 4 15 2 2 3 1 2.5 15 10 2 16 2 3 1 3 2.5 20 4 4 17 2 3 2 1 2.5 20 7 2 18 2 3 3 2 2.5 20 10 3 h. m. ibrahim and r. h. salman / iraqi journal of chemical and petroleum engineering 23,1 (2022) 31 41 34 3results and discussion 3.1. multiple regression model and the s/n results the multiple regression equation (eq. (12)) which was acquired by minitab 17 software is shown as follows which represents the relationship between cod re% and the studied factors. the value of the correlation coefficient (r 2 ) of this equation is equal to 98.05 % which states an excellent fitting of the model. cod re = [0.067 +0.1771 x1+0.0742 x2-0.02930 x3-0.0203 x40.001563 x2^2-0.00898 x1*x2-0.00333 x2*x4]*100 (12) table 3 represents the values of experimental cod re% and the predicted ones that were determined based on eq. (12). also, this table shows the values of s/n ratios that were calculated based on eq. (11) and the values of energy consumed that were determined by eq. (10). it is clear from table 3 that the successive ec-eo processes were very efficient in the reduction of turbidity, where high reduction percentages ranging between 97.14 99.68% were attained. table 3. the values of experimental and predicted cod re%, turbidity re%, s/n, and energy intake exp. no. nacl (g/l) c.d. (ma/cm 2 ) ph time (h) cod re%, exp. cod re%, pred. turbidity re % enc (kwh/m 3 ) s/n ratio 1 1.5 10 4 2 66.86 69.25 99.21 10.11 -3.4968 2 1.5 10 7 3 61.95 61.76 98.83 15.51 -4.1594 3 1.5 10 10 4 55.04 54.27 98.92 20.21 -5.1868 4 1.5 15 4 2 84.58 83.40 99.49 21.50 -1.4549 5 1.5 15 7 3 80.92 77.58 99.68 32.25 -1.8386 6 1.5 15 10 4 70.03 71.75 98.32 45.12 -3.0948 7 1.5 20 4 3 93.40 94.38 99.37 54.29 -0.5932 8 1.5 20 7 4 89.35 90.22 99.16 75.20 -0.9781 9 1.5 20 10 2 72.56 72.17 98.62 37.13 -2.7857 10 2.5 10 4 4 78.61 80.58 98.03 18.33 -2.0901 11 2.5 10 7 2 71.15 69.19 97.87 9.87 -2.9559 12 2.5 10 10 3 63.07 61.70 97.14 13.04 -4.0034 13 2.5 15 4 3 90.58 90.61 99.31 26.44 -0.8596 14 2.5 15 7 4 85.61 84.78 98.57 36.66 -1.3492 15 2.5 15 10 2 66.40 70.06 97.87 18.33 -3.5568 16 2.5 20 4 4 99.81 98.76 99.08 62.04 -0.0161 17 2.5 20 7 2 81.27 80.71 99.08 29.14 -1.8011 18 2.5 20 10 3 76.27 76.55 98.92 47.24 -2.3527 fig. 1 shows an evaluation of the experimental and predicted values of cod re%. it is very obvious that the model predicts very well for cod re% and eq. (12) can essentially reveal the process valuation. fig. 1. experimental and predicted cod re% values for successive ec-eo processes table 4 represents the mean value of cod re% of each studied parameter at a definite level and it is represented graphically in fig. 2. based on the results of this table, the most governing factors are in the following order: c.d. ˃ ph ˃ time ˃ nacl concentration. table 4. values of mean of response for data attained from cod re% reduction experiments level nacl (g/l) c.d. (ma/cm 2 ) ph time (h) 1 75 66.11 85.64 73.8 2 79.2 79.69 78.38 77.7 3 85.44 67.23 79.74 delta 4.23 19.33 18.41 5.94 rank 4 1 2 3 fig. 2. main effects plot for means values of cod re% for successive ec-eo process h. m. ibrahim and r. h. salman / iraqi journal of chemical and petroleum engineering 23,1 (2022) 31 41 35 the predicted values of s/n ratios (hb) and the ranks for each dominant factor based on eq. (11) are presented in table 5, and it is represented graphically in fig. 3. a higher s/n ratio value specifies a higher cod re%, and the acquired ranks for each parameter show the same order of significance as that obtained with mean response. table 5. response table for s/n ratio (higher is better) level nacl (g/l) c. d. (ma/cm 2 ) ph time (h) 1 -2.621 -3.649 -1.418 -2.675 2 -2.109 -2.026 -2.180 -2.301 3 -1.421 -3.497 -2.119 delta 0.511 2.228 2.078 0.556 rank 4 1 2 3 fig. 3. main effect plots of s/n ratio (higher is better) for cod re% based on the results of s/n ratios, the optimum conditions were: nacl conc. (x1) of 2.5 g/l, c.d. (x2) of 20 ma/cm 2 , ph (x3) of 4, and time (x4) of 4 h. at these conditions, two confirmation experiments were accomplished with cod re% of 97.88% and 98.36% respectively and therefore the higher reduction efficiency of cod was 98.12 %, with energy consumption of about 62.04 kwh/m 3 . 3.2. analysis of variance (anova) anova is a statistical method for optimization that offers a superior understanding of how the perceived results are consistent and the significance of the studied parameters can be attained [33, 34]. the influence of each parameter on the response can be attained by f-test. if f-test values > 1, this means that those parameters have a higher influence [26, 33]. when the p-value of each factor is less than 0.05 (for a confidence level of 95%) this means that the experiments were conducted at controlled conditions [26]. table 6 shows the results of anova which shows that c.d. (with contribution of 47%) has the major influence on cod re% followed by ph (with contribution of 41.03%) and time (with a contribution of 4.34%), and the less effective parameter on cod re% was nacl conc. (with contribution of 3.21%). the results of the f and p-value reveal that all factors have a significant effect on cod re%. table 6. analysis of variance (anova) for cod re% for successive ec-eo system source df seq ss contribution % adj ss adj ms f-value p-value nacl 1 0.008066 3.21% 0.008066 0.008066 7.26 0.023 c. d. 2 0.118213 47.00% 0.118213 0.059106 53.21 0.000 ph 2 0.103209 41.03% 0.103209 0.051605 46.45 0.000 time 2 0.010921 4.34% 0.010921 0.005461 4.92 0.033 error 10 0.011109 4.42% 0.011109 0.001111 total 17 0.251518 100.00% model summary s r-sq r-sq(adj) r-sq(pred) 0.0333302 95.58% 92.49% 85.69% 3.3. effect of controllable parameters a. effect of nacl conc. chlorine is often used to enhance the effluent's cond. during treatment. chlorine species that are produced at the anode like hypochlorous acid and hypochlorite ions can degrade organic compounds in the indirect eo process. oxidants are usually stable and move in the bulk solution, where they then indirectly oxidize the waste, which is promoted by the hydrodynamic architecture of the electrochemical cell [35, 36, 37]. increasing electrolyte conductivity, decreasing cell voltage, decreasing electrolyte resistance, and decreasing enc can be attained by nacl addition [38]. so, to eliminate cod and color from wastewater, nacl can be added as an oxidizing agent in electrochemical systems due to its probable contribution in electro-catalytic degradation. the content of cl (final) output in the treated wastewater was found to be 16 % lower than (initial) intake wastewater in successive ec-eo process, providing significant evidence for the above conclusion [39]. h. m. ibrahim and r. h. salman / iraqi journal of chemical and petroleum engineering 23,1 (2022) 31 41 36 table 7 represents the values of initial and final cond. for each conducted experiment in the ec-eo successive system. so, the value of cond. reduction % can be obtained. fig. 4 illustrates the 2d and 3d surface plot for cod re% vs. c.d. and nacl conc., and it is clear that the reduction percentage increases with c.d. and nacl conc. increasing due to the increase in the hypochlorous acid generation. previous research has shown similar results [40]. the role of electrocatalytic degradation of organic components is strengthened, but too much supporting electrolyte results in a significant number of ions adsorbing on the electrode surface, lowering current utilization [39]. table 7. the values of initial and final cond., and conductivity reduction % exp. no. nacl (g/l) c.d. (ma/cm 2 ) ph time (h) initial cond. (ms/cm) final cond. (ms/cm) cond. re % 1 1.5 10 4 2 7.04 6.37 10 2 1.5 10 7 3 7.13 6.22 13 3 1.5 10 10 4 7.17 6.28 12 4 1.5 15 4 2 7.29 6.04 17 5 1.5 15 7 3 7.1 6.35 11 6 1.5 15 10 4 7.18 6.34 12 7 1.5 20 4 3 7.22 5.35 26 8 1.5 20 7 4 7.17 6.15 14 9 1.5 20 10 2 7.16 5.78 19 10 2.5 10 4 4 9.12 6.12 33 11 2.5 10 7 2 8.9 8.08 9 12 2.5 10 10 3 8.94 8.16 9 13 2.5 15 4 3 8.96 7.12 21 14 2.5 15 7 4 8.98 6.89 23 15 2.5 15 10 2 8.93 8.22 8 16 2.5 20 4 4 9.05 7.38 18 17 2.5 20 7 2 8.93 7.55 15 18 2.5 20 10 3 8.99 8.06 10 average cond. re% 16% fig. 4. 2d and 3d surface plot of cod re% vs. c. d. and nacl conc. b. effect of current density current density is considered the most vital element that affects treatment effectiveness in any electrochemical process. as known, it is not surprising that increasing c.d. results in higher pollutants degradation efficiency. in the present study, different current densities (10, 15, and 20 ma /cm2) were conducted to treat wastewater, and it is evident from all illustrated results that the greatest value of cod re% was obtained at 20 ma /cm2. in the eo process, current density increasing means an increase in the hocl generation. while in the ec process it is known that increasing current density leads to a significant amount of generated flocs and a significant growth rate due to more release of aluminum ions by anodic dissolution (according to faraday's law). so, more generation of aluminum hydroxides necessary to coagulants formation is increased with c.d. increasing [14]. but also it must be taken into consideration that high current density promoted the degradation of sacrificial electrodes with a high energy cost related to the voltage necessary to complete the process [9, 40 .] c. effect of time according to faraday’s law, electrolysis time is an essential factor and it influences the generation rate of active chlorine and al+3 ions and the operative costs. the treatment of wastewater by ec process was accomplished in all experiments in 1 h and the treatment by eo process was achieved in the remaining time (13h). fig. 5 depicts the 2d and 3d surface plots for cod re% vs. c.d. and time. h. m. ibrahim and r. h. salman / iraqi journal of chemical and petroleum engineering 23,1 (2022) 31 41 37 fig. 5 indicates that cod reduction efficiency increases rapidly with increasing time at all c.d. values. these findings are consistent with other previous studies [41, 42]. it is known that the ec process is moderately rapid and it is very active in eliminating colloidal and suspended particles but at the same time there are many limitations in removing persistent organics by the ec process. the eo process is very operative in the reduction of cod but demands so much time [43]. fig. 5. 2d and 3d surface plot of cod re% vs. c. d. and time for successive ec-eo system d. effect of ph fig. 6 illustrates the 2d and 3d surface plots for cod re% vs. c.d. and ph. the highest values of cod reduction percentage are achieved at a ph range of 4–5.5. different species of al may be formed when al is dissolved (electrochemically and chemically) depending on the ph and the presence of other chemical species. in the ph range, 4–9, al(oh) +2 , al(oh)2 + , al(oh)3, al2(oh)2 +4 , and al13(oh)32 +7 are produced. these species have a high positive charge on the surface, which might cause an adsorption electrochemistry neutralization reaction [44]. at high ph values, active chlorine appears as hypochlorite, which is a less effective oxidant toward organic species than hypochlorous acid, which is a highly strong oxidant and the dominant component at low ph values [45]. for all c.d. (1020ma/cm 2 ), the reduction efficiency of cod increases exponentially at ph (4), this effect on cod reduction is consistent with some previous studies [41, 46]. this might be explained that an increase in c.d. would result in an increase in the production of hypochlorous acid in acidic solutions and hypochlorite in alkaline solutions, favoring the degradation of organic components via the indirect oxidation process [46]. so, based on these explanations and results of this study; the acidic conditions are preferred for high cod re% in the successive ec-eo process. fig. 6. 2d and 3d surface plot of cod re% vs. c. d. and ph 3.4. electrical energy consumption in electrochemical research and other wastewater treatment technologies, energy consumption is a vital topic. in addition to high reduction efficiency, wastewater treatment systems must also use less energy. in all electrochemical experiments, the energy consumption is inversely related to the solution's electrical conductivity (cond.) and directly related to the c.d. used. improvements in electrolyte convection and decreasing the distance between the cathode and anode may reduce power consumption [47, 48]. by plotting the effect of c.d. on the enc (eq. (10)) in fig. 7, it is clear that the energy consumption values increase with c.d. increasing. fig. 7. electrical energy consumption for successive eceo process at different c. d. and time =4 h, vol. = 2 l, nacl conc. = 2.5 g/l, ph= 4 4conclusion the current study showed that the wastewater from the midland refinery company in baghdadiraq was successfully treated using two successive processes eceo. the reductions of organic and inorganic contaminants were removed with final concentrations below the standard limits. the impacts of several operating parameters such as c.d., primary ph, nacl conc., and electrolysis time on cod re% were examined and optimized by the taguchi approach. h. m. ibrahim and r. h. salman / iraqi journal of chemical and petroleum engineering 23,1 (2022) 31 41 38 increasing the current density and time was result in higher efficiency reduction. the value of time must be chosen for efficient treatment because energy consumption increases with increasing c.d. and time. increasing nacl conc. increases wastewater conductivity, lowers cell voltage, and minimizes electrical energy consumption. cod re% was inversely proportional with ph increasing. the optimum conditions for wastewater treatment by successive ec-eo process were c.d. (20 ma/cm 2 ), ph (4), time (4 h), and nacl conc. (2.5 g/l). at these conditions, approximately 98.12 % of cod reduction was achieved with energy consumption of about 62.04 kwh/m 3 . the results of anova revealed that c.d. has the major effect on cod re% followed by ph, time and the less effective parameter on cod re% was nacl conc. based on the results of the f-value of the present study, all the studied factors have a significant effect on cod re%. nomenclature nomenclature meaning units adjms adjusted mean of square adjss adjusted sum of square c.d. current density ma/cm 2 𝐶𝑂𝐷0 initial value of chemical oxygen demand ppm 𝐶𝑂𝐷𝑓 final value of chemical oxygen demand ppm cond. conductivity μs/cm df degree of freedom enc electrical energy consumption kwh/m 3 i current a n number of repetitions nacl conc. nacl concentration g/l 𝑅𝑒 % reduction percentage 𝑡 time h tds total dissolved solids mg/l uc potential volts v volume m 3 yi performance results of the ith experiment references [1] p.v. nidheesh, j. scaria, d. s. babua, and m. s. kumar ‘an overview on combined electrocoagulationdegradation processes for the effective treatment of water and wastewater’, chemosphere, vol. 263, january, 127907, 2021. [2] l. wei, s. guo, g. yan, c. chen, and x. jiang, “electrochemical pretreatment of heavy oil refinery wastewater using a three-dimensional electrode reactor”, electrochimica acta, vol. 55, no. (28), pp. 8615–8620, 2010. [3] e. gilpavas, i. dobrosz-gómez, and m. a. gómezgarcía, “efficient treatment for textile wastewater through sequential electrocoagulation, electrochemical oxidation and adsorption processes: optimization and toxicity assessment”, journal of electroanalytical chemistry, vol. 878, no. (december), 2020. [4] k. r. kalasha, t. m. albayati, “remediation of oil refinery wastewater implementing functionalized mesoporous materials mcm-41 in batch and continuous adsorption process”, desalination and water treatment, vol. 220, pp. 130–141, 2021. [5] z. fang, c. he, y. lia, k. h. chung, c. xu, q. shi,” fractionation and characterization of dissolved organic matter (dom) in refinery wastewater by revised phase retention and ion-exchange adsorption solid phase extraction followed by esi ft-icr ms”, talanta, vol. 162, no. 1 (january), pp. 466-473, 2017 [6] s. a. younis, n. sh. el-gendy, w. i. el-azab, and y. m. moustafa, “kinetic, isotherm, and thermodynamic studies of polycyclic aromatic hydrocarbons biosorption from petroleum refinery wastewater using spent waste biomass” desalination and water treatment, vol. 56, issue 11, pp. 3013-3023, 2015. [7] b. santos, j. g. crespo, m. a. santos, s. velizarov, “oil refinery hazardous effluents minimization by membrane filtration: an on-site pilot plant study”, journal of environmental management, vol. 181, no. 1 (october), pp. 762-769, 2016. [8] b. singh, and p. kumar, "pre-treatment of petroleum refinery wastewater by coagulation and flocculation using mixed coagulant: optimization of process parameters using response surface methodology (rsm)”, journal of water process engineering, vol. 36, pp. 2–17, 2020. [9] a. s. fahim, and a. h. abbar, “optimization of process parameters for the electrochemical oxidation treatment of petroleum refinery wastewater using porous graphite anode”, al-qadisiyah journal for engineering sciences, vol. 13, no. (2), pp. 125–135, 2020. [10] m. saeedi, and a. khalvati-fahlyani, “treatment of oily wastewater of a gas refinery by electrocoagulation using al electrodes”, water environment research, vol. 83, no. (3), pp. 256–264, 2011. [11] k. juttner, u. galla, and h. schmieder, “electrochemical approaches to environmental problems in the process industry”, electrochimica acta, vol. 45, no. 3 (may), pp. 2575-2594, 2000. [12] p. kariyajjanavar, j. narayana, and y. a. nayaka, “degradation of textile wastewater by electrochemical method”, journal of waste water treatment & analysis, vol. 2, no. (01), pp. 1–7, 2011. [13] s. safari, m. azadi aghdam, and h. r. kariminia, “electrocoagulation for cod and diesel reduction from oily wastewater”, international journal of environmental science and technology, vol. 13, no. (1), pp. 231–242, 2016. https://www.sciencedirect.com/science/article/abs/pii/s0045653520321020 https://www.sciencedirect.com/science/article/abs/pii/s0045653520321020 https://www.sciencedirect.com/science/article/abs/pii/s0045653520321020 https://www.sciencedirect.com/science/article/abs/pii/s0045653520321020 https://www.sciencedirect.com/science/article/abs/pii/s0045653520321020 https://www.sciencedirect.com/science/article/abs/pii/s0013468610010662 https://www.sciencedirect.com/science/article/abs/pii/s0013468610010662 https://www.sciencedirect.com/science/article/abs/pii/s0013468610010662 https://www.sciencedirect.com/science/article/abs/pii/s0013468610010662 https://www.sciencedirect.com/science/article/abs/pii/s0013468610010662 https://www.sciencedirect.com/science/article/abs/pii/s1572665720308067 https://www.sciencedirect.com/science/article/abs/pii/s1572665720308067 https://www.sciencedirect.com/science/article/abs/pii/s1572665720308067 https://www.sciencedirect.com/science/article/abs/pii/s1572665720308067 https://www.sciencedirect.com/science/article/abs/pii/s1572665720308067 https://www.sciencedirect.com/science/article/abs/pii/s1572665720308067 https://d1wqtxts1xzle7.cloudfront.net/69477016/220_2021_130-with-cover-page-v2.pdf?expires=1648292082&signature=k-kftiqhvm7y9eosuhyjnfir-22ms5rw4zvt0nbe-brt4noyt0e6jqwxwptcmdfrxngtytdwakhrhilyswicqbioeo27~78sndt5idpxljy~gjdn6yqpgyupnhm60ozkfnzaaenqenretbexuuyi3lwnq3fgzc2xrpqane3nvljpxosi9lvvmmby474i9bhrpmmz56nj1qrd33wka1lb4bqcatizomlbi1ih3e-goyekhtto7engzk9qrlwy2zxnctbxrskcfswabkyhn4eo8ekvdsdmnmih4vyijntsbdqv8haxol6dfa5an-en22qwo2amtxjzahnrptuvwhvmyw__&key-pair-id=apkajlohf5ggslrbv4za 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https://www.sciencedirect.com/science/article/abs/pii/s0039914016308165 https://www.sciencedirect.com/science/article/abs/pii/s0039914016308165 https://www.sciencedirect.com/science/article/abs/pii/s0039914016308165 https://www.sciencedirect.com/science/article/abs/pii/s0039914016308165 https://www.sciencedirect.com/science/article/abs/pii/s0039914016308165 https://www.sciencedirect.com/science/article/abs/pii/s0039914016308165 https://www.sciencedirect.com/science/article/abs/pii/s0039914016308165 https://www.tandfonline.com/doi/abs/10.1080/19443994.2014.964331 https://www.tandfonline.com/doi/abs/10.1080/19443994.2014.964331 https://www.tandfonline.com/doi/abs/10.1080/19443994.2014.964331 https://www.tandfonline.com/doi/abs/10.1080/19443994.2014.964331 https://www.tandfonline.com/doi/abs/10.1080/19443994.2014.964331 https://www.tandfonline.com/doi/abs/10.1080/19443994.2014.964331 https://www.sciencedirect.com/science/article/pii/s0301479716304649 https://www.sciencedirect.com/science/article/pii/s0301479716304649 https://www.sciencedirect.com/science/article/pii/s0301479716304649 https://www.sciencedirect.com/science/article/pii/s0301479716304649 https://www.sciencedirect.com/science/article/pii/s0301479716304649 https://www.sciencedirect.com/science/article/abs/pii/s2214714420301963 https://www.sciencedirect.com/science/article/abs/pii/s2214714420301963 https://www.sciencedirect.com/science/article/abs/pii/s2214714420301963 https://www.sciencedirect.com/science/article/abs/pii/s2214714420301963 https://www.sciencedirect.com/science/article/abs/pii/s2214714420301963 https://www.sciencedirect.com/science/article/abs/pii/s2214714420301963 http://www.qu.edu.iq/journaleng/index.php/jqes/article/view/652 http://www.qu.edu.iq/journaleng/index.php/jqes/article/view/652 http://www.qu.edu.iq/journaleng/index.php/jqes/article/view/652 http://www.qu.edu.iq/journaleng/index.php/jqes/article/view/652 http://www.qu.edu.iq/journaleng/index.php/jqes/article/view/652 http://www.qu.edu.iq/journaleng/index.php/jqes/article/view/652 https://onlinelibrary.wiley.com/doi/abs/10.2175/106143010x12780288628499 https://onlinelibrary.wiley.com/doi/abs/10.2175/106143010x12780288628499 https://onlinelibrary.wiley.com/doi/abs/10.2175/106143010x12780288628499 https://onlinelibrary.wiley.com/doi/abs/10.2175/106143010x12780288628499 https://onlinelibrary.wiley.com/doi/abs/10.2175/106143010x12780288628499 https://www.sciencedirect.com/science/article/abs/pii/s001346860000339x https://www.sciencedirect.com/science/article/abs/pii/s001346860000339x https://www.sciencedirect.com/science/article/abs/pii/s001346860000339x https://www.sciencedirect.com/science/article/abs/pii/s001346860000339x https://cetree.usm.my/images/videos/tot_kimia/1/degradation_of_textile_wastewater_by_electrochemical_method.pdf https://cetree.usm.my/images/videos/tot_kimia/1/degradation_of_textile_wastewater_by_electrochemical_method.pdf https://cetree.usm.my/images/videos/tot_kimia/1/degradation_of_textile_wastewater_by_electrochemical_method.pdf https://cetree.usm.my/images/videos/tot_kimia/1/degradation_of_textile_wastewater_by_electrochemical_method.pdf https://link.springer.com/article/10.1007/s13762-015-0863-5 https://link.springer.com/article/10.1007/s13762-015-0863-5 https://link.springer.com/article/10.1007/s13762-015-0863-5 https://link.springer.com/article/10.1007/s13762-015-0863-5 https://link.springer.com/article/10.1007/s13762-015-0863-5 h. m. ibrahim and r. h. salman / iraqi journal of chemical and petroleum engineering 23,1 (2022) 31 41 39 [14] r. h. salman, “removal of manganese ions (mn 2+ ) from a simulated wastewater by electrocoagulation/ electroflotation technologies with stainless steel mesh electrodes: process optimization based on taguchi approach”, iraqi journal of chemical and petroleum engineering, vol. 20, no.1 (march), pp. 39–48, 2019. [15] s.i. chaturvedi, “electrocoagulation: a novel waste water treatment method”, international journal of modern engineering research, vol. 3, no. (1), pp. 93–100, 2013. [16] e. ali, and z. yaakob, “electrocoagulation for treatment of industrial effluents and hydrogen production”, in electrolysis. intech, pp. 227–242, 2012. [17] a. m. al-yaqoobi, m. n. al-rikabey, and m. k. h. al-mashhadani, “electrochemical harvesting of microalgae꞉ parametric and cost-effectivity comparative investigation”, chem. ind. chem. eng. q., vol. 27, no. 2, pp. 121–130, 2021. [18] a. m. al-yaqoobi, m. n. al-rikabey, and k. h. r. algharrawi, “treatment of dairy wastewater by electrocoagulation and ultrasonic-assisted electrocoagulation methods”, environ. eng. manag. j., vol. 20, no. 6, 2021. [19] d. rajkumar, j. g. kim, and k. palanivelu, “indirect electrochemical oxidation of phenol in the presence of chloride for wastewater treatment”, chemical engineering and technology, vol. 28, no. (1), pp. 98–105, 2005. [20] s. y. bashtan, and v. a. bagrii, “electrochemical oxidation of phenol on metal oxide electrodes”, journal of water chemistry and technology, vol. 34, no. (1), pp. 24–27, 2012. [21] a. s. abbas, m. h. hafiz, and r. h. salman, “indirect electrochemical oxidation of phenol using rotating cylinder reactor”, iraqi journal of chemical and petroleum engineering, vol.17, no.4 (december), pp. 43-55, 2016. [22] h. m. ibrahim, r. h. salman, “real wastewater treatment by electrocoagulationelectro-oxidation combined system: optimization using taguchi approach”, egypt. j. chem., vol. 65, no. (3), pp. 135 – 145, 2022. [23] a. h. abbar, r. h. salman, and a. s. abbas, “cadmium removal using a spiral-wound woven wire meshes packed bed rotating cylinder electrode”, environmental technology and innovation, vol. 13, pp. 233–243, 2019. [24] h. kermet-said, and n. moulai-mostefa, “optimization of turbidity and cod removal from pharmaceutical wastewater by electrocoagulation. isotherm modeling and cost analysis”, pol. j. environ. stud., vol. 24, no. 3, pp. 1049-1061, 2015. [25] h. n. ibarra-taquez, e. gilpavas, e. r. blatchley, m. gómez-garcía, and i. dobrosz gómez “integrated electrocoagulation-electrooxidation process for the treatment of soluble coffee effluent: optimization of cod degradation and operation time analysis”, journal of environmental management, vol. 200, no. (15), pp. 530–538, 2017. [26] f. googerdchian, a. moheb, r. emadi, and m. asgari, “optimization of pb(ii) ions adsorption on nanohydroxyapatite adsorbents by applying taguchi method”, journal of hazardous materials, vol. 349, pp. 186–194, 2018. [27] s. s. madan, and k. l. wasewar, “optimization for benzeneacetic acid removal from aqueous solution using cao2 nanoparticles based on taguchi method”, journal of applied research and technology, vol. 15, no. (4), pp. 332–339, 2017. [28] m. vega, r. pardo, e. barrado, m. a. fuente, j. valle, “application of the taguchi experimental design to the optimisation of a photo-oxidation procedure for trace metal analysis in freshwater”, fresenius' journal of analytical chemistry, vol. 350, no. (3), pp. 139– 144, 1994. [29] g. barman, a. kumar, and p. khare, “removal of congo red by carbonized low-cost adsorbents: process parameter optimization using a taguchi experimental design”, journal of chemical and engineering data, vol. 56, no. (11), pp. 4102–4108, 2011. [30] y. q. wang, j. byun, b. s. kim, j. song, and t. chou, ‘the use of taguchi optimization in determining optimum electrophoretic conditions for the deposition of carbon nanofiber on carbon fibers for use in carbon/epoxy composites”, carbon, vol. 50, no. (8), pp. 2853–2859, 2012. [31] j. f. martínez-villafañe, and c. monteroocampo, “optimisation of energy consumption in arsenic electro-removal from groundwater by the taguchi method”, separation and purification technology, vol. 70, no. (3), pp. 302–305, 2010. [32] s. varala, alka kumari, b. dharanija, suresh k. bhargava, r. parthasarathy, and b. satyavathi “removal of thorium (iv) from aqueous solutions by deoiled karanja seed cake: optimization using taguchi method, equilibrium, kinetic and thermodynamic studies”, journal of environmental chemical engineering, vol. 4, no. (1), pp. 405–417, 2016. [33] a. salahi, and t. mohammadi, “oily wastewater treatment by ultrafiltration using taguchi experimental design”, water science & technology, vol. 63, no, (7), pp. 1476–1484, 2011. [34] b. razmi, and r. ghasemi-fasaei, “investigation of taguchi optimization, equilibrium isotherms, and kinetic modeling for phosphorus adsorption onto natural zeolite of clinoptilolite type”, adsorption science & technology, vol. 1, no. (14), pp. 1–13, 2018. https://doi.org/10.31699/ijcpe.2019.1.6 https://doi.org/10.31699/ijcpe.2019.1.6 https://doi.org/10.31699/ijcpe.2019.1.6 https://doi.org/10.31699/ijcpe.2019.1.6 https://doi.org/10.31699/ijcpe.2019.1.6 https://doi.org/10.31699/ijcpe.2019.1.6 https://doi.org/10.31699/ijcpe.2019.1.6 https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.416.7872&rep=rep1&type=pdf https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.416.7872&rep=rep1&type=pdf https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.416.7872&rep=rep1&type=pdf https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.416.7872&rep=rep1&type=pdf https://books.google.iq/books?hl=en&lr=&id=-boedwaaqbaj&oi=fnd&pg=pa227&dq=%5b16%5d%09e.+ali,+and+z.+yaakob,+%e2%80%9celectrocoagulation+for+treatment+of+industrial+effluents+and+hydrogen+production%e2%80%9d,+in+electrolysis.+intech,+pp.+227%e2%80%93242,+2012.&ots=zmqortgxdu&sig=8_r70wxkzagmc4jqejc381vsaom&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=-boedwaaqbaj&oi=fnd&pg=pa227&dq=%5b16%5d%09e.+ali,+and+z.+yaakob,+%e2%80%9celectrocoagulation+for+treatment+of+industrial+effluents+and+hydrogen+production%e2%80%9d,+in+electrolysis.+intech,+pp.+227%e2%80%93242,+2012.&ots=zmqortgxdu&sig=8_r70wxkzagmc4jqejc381vsaom&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=-boedwaaqbaj&oi=fnd&pg=pa227&dq=%5b16%5d%09e.+ali,+and+z.+yaakob,+%e2%80%9celectrocoagulation+for+treatment+of+industrial+effluents+and+hydrogen+production%e2%80%9d,+in+electrolysis.+intech,+pp.+227%e2%80%93242,+2012.&ots=zmqortgxdu&sig=8_r70wxkzagmc4jqejc381vsaom&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=-boedwaaqbaj&oi=fnd&pg=pa227&dq=%5b16%5d%09e.+ali,+and+z.+yaakob,+%e2%80%9celectrocoagulation+for+treatment+of+industrial+effluents+and+hydrogen+production%e2%80%9d,+in+electrolysis.+intech,+pp.+227%e2%80%93242,+2012.&ots=zmqortgxdu&sig=8_r70wxkzagmc4jqejc381vsaom&redir_esc=y#v=onepage&q&f=false http://www.doiserbia.nb.rs/article.aspx?id=1451-93722000031a#.yj7wv9jbziu http://www.doiserbia.nb.rs/article.aspx?id=1451-93722000031a#.yj7wv9jbziu http://www.doiserbia.nb.rs/article.aspx?id=1451-93722000031a#.yj7wv9jbziu http://www.doiserbia.nb.rs/article.aspx?id=1451-93722000031a#.yj7wv9jbziu http://www.doiserbia.nb.rs/article.aspx?id=1451-93722000031a#.yj7wv9jbziu https://web.p.ebscohost.com/abstract?direct=true&profile=ehost&scope=site&authtype=crawler&jrnl=15829596&an=151462966&h=puutefqlhvymka3twht2o2cqt3aq%2fhxibrymrzp2k2wxqte1fexoqtazubrl332rskizt%2fl%2b%2fnrwzh%2fr5atbva%3d%3d&crl=c&resultns=adminwebauth&resultlocal=errcrlnotauth&crlhashurl=login.aspx%3fdirect%3dtrue%26profile%3dehost%26scope%3dsite%26authtype%3dcrawler%26jrnl%3d15829596%26an%3d151462966 https://web.p.ebscohost.com/abstract?direct=true&profile=ehost&scope=site&authtype=crawler&jrnl=15829596&an=151462966&h=puutefqlhvymka3twht2o2cqt3aq%2fhxibrymrzp2k2wxqte1fexoqtazubrl332rskizt%2fl%2b%2fnrwzh%2fr5atbva%3d%3d&crl=c&resultns=adminwebauth&resultlocal=errcrlnotauth&crlhashurl=login.aspx%3fdirect%3dtrue%26profile%3dehost%26scope%3dsite%26authtype%3dcrawler%26jrnl%3d15829596%26an%3d151462966 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https://web.p.ebscohost.com/abstract?direct=true&profile=ehost&scope=site&authtype=crawler&jrnl=15829596&an=151462966&h=puutefqlhvymka3twht2o2cqt3aq%2fhxibrymrzp2k2wxqte1fexoqtazubrl332rskizt%2fl%2b%2fnrwzh%2fr5atbva%3d%3d&crl=c&resultns=adminwebauth&resultlocal=errcrlnotauth&crlhashurl=login.aspx%3fdirect%3dtrue%26profile%3dehost%26scope%3dsite%26authtype%3dcrawler%26jrnl%3d15829596%26an%3d151462966 https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.200407002 https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.200407002 https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.200407002 https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.200407002 https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.200407002 https://link.springer.com/article/10.3103/s1063455x12010043 https://link.springer.com/article/10.3103/s1063455x12010043 https://link.springer.com/article/10.3103/s1063455x12010043 https://link.springer.com/article/10.3103/s1063455x12010043 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/232 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/232 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/232 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/232 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/232 https://journals.ekb.eg/article_194570.html https://journals.ekb.eg/article_194570.html https://journals.ekb.eg/article_194570.html https://journals.ekb.eg/article_194570.html https://journals.ekb.eg/article_194570.html https://www.sciencedirect.com/science/article/abs/pii/s2352186418303912 https://www.sciencedirect.com/science/article/abs/pii/s2352186418303912 https://www.sciencedirect.com/science/article/abs/pii/s2352186418303912 https://www.sciencedirect.com/science/article/abs/pii/s2352186418303912 https://www.sciencedirect.com/science/article/abs/pii/s2352186418303912 http://www.pjoes.com/optimization-of-turbidity-and-cod-removal-from-pharmaceutical-wastewater-by-electrocoagulation-isotherm-modeling-and-cost-analysis,50877,0,2.html http://www.pjoes.com/optimization-of-turbidity-and-cod-removal-from-pharmaceutical-wastewater-by-electrocoagulation-isotherm-modeling-and-cost-analysis,50877,0,2.html http://www.pjoes.com/optimization-of-turbidity-and-cod-removal-from-pharmaceutical-wastewater-by-electrocoagulation-isotherm-modeling-and-cost-analysis,50877,0,2.html http://www.pjoes.com/optimization-of-turbidity-and-cod-removal-from-pharmaceutical-wastewater-by-electrocoagulation-isotherm-modeling-and-cost-analysis,50877,0,2.html http://www.pjoes.com/optimization-of-turbidity-and-cod-removal-from-pharmaceutical-wastewater-by-electrocoagulation-isotherm-modeling-and-cost-analysis,50877,0,2.html https://www.sciencedirect.com/science/article/pii/s0301479717305807 https://www.sciencedirect.com/science/article/pii/s0301479717305807 https://www.sciencedirect.com/science/article/pii/s0301479717305807 https://www.sciencedirect.com/science/article/pii/s0301479717305807 https://www.sciencedirect.com/science/article/pii/s0301479717305807 https://www.sciencedirect.com/science/article/pii/s0301479717305807 https://www.sciencedirect.com/science/article/pii/s0301479717305807 https://www.sciencedirect.com/science/article/abs/pii/s0304389418300712 https://www.sciencedirect.com/science/article/abs/pii/s0304389418300712 https://www.sciencedirect.com/science/article/abs/pii/s0304389418300712 https://www.sciencedirect.com/science/article/abs/pii/s0304389418300712 https://www.sciencedirect.com/science/article/abs/pii/s0304389418300712 https://www.sciencedirect.com/science/article/pii/s1665642317300585 https://www.sciencedirect.com/science/article/pii/s1665642317300585 https://www.sciencedirect.com/science/article/pii/s1665642317300585 https://www.sciencedirect.com/science/article/pii/s1665642317300585 https://www.sciencedirect.com/science/article/pii/s1665642317300585 https://link.springer.com/article/10.1007/bf00323176 https://link.springer.com/article/10.1007/bf00323176 https://link.springer.com/article/10.1007/bf00323176 https://link.springer.com/article/10.1007/bf00323176 https://link.springer.com/article/10.1007/bf00323176 https://link.springer.com/article/10.1007/bf00323176 https://pubs.acs.org/doi/abs/10.1021/je200554z https://pubs.acs.org/doi/abs/10.1021/je200554z https://pubs.acs.org/doi/abs/10.1021/je200554z https://pubs.acs.org/doi/abs/10.1021/je200554z https://pubs.acs.org/doi/abs/10.1021/je200554z https://pubs.acs.org/doi/abs/10.1021/je200554z https://www.sciencedirect.com/science/article/abs/pii/s0008622312001868 https://www.sciencedirect.com/science/article/abs/pii/s0008622312001868 https://www.sciencedirect.com/science/article/abs/pii/s0008622312001868 https://www.sciencedirect.com/science/article/abs/pii/s0008622312001868 https://www.sciencedirect.com/science/article/abs/pii/s0008622312001868 https://www.sciencedirect.com/science/article/abs/pii/s0008622312001868 https://www.sciencedirect.com/science/article/abs/pii/s1383586609004201 https://www.sciencedirect.com/science/article/abs/pii/s1383586609004201 https://www.sciencedirect.com/science/article/abs/pii/s1383586609004201 https://www.sciencedirect.com/science/article/abs/pii/s1383586609004201 https://www.sciencedirect.com/science/article/abs/pii/s1383586609004201 https://www.sciencedirect.com/science/article/abs/pii/s2213343715300804 https://www.sciencedirect.com/science/article/abs/pii/s2213343715300804 https://www.sciencedirect.com/science/article/abs/pii/s2213343715300804 https://www.sciencedirect.com/science/article/abs/pii/s2213343715300804 https://www.sciencedirect.com/science/article/abs/pii/s2213343715300804 https://www.sciencedirect.com/science/article/abs/pii/s2213343715300804 https://www.sciencedirect.com/science/article/abs/pii/s2213343715300804 https://www.sciencedirect.com/science/article/abs/pii/s2213343715300804 https://iwaponline.com/wst/article-abstract/63/7/1476/14208/oily-wastewater-treatment-by-ultrafiltration-using https://iwaponline.com/wst/article-abstract/63/7/1476/14208/oily-wastewater-treatment-by-ultrafiltration-using https://iwaponline.com/wst/article-abstract/63/7/1476/14208/oily-wastewater-treatment-by-ultrafiltration-using https://iwaponline.com/wst/article-abstract/63/7/1476/14208/oily-wastewater-treatment-by-ultrafiltration-using https://journals.sagepub.com/doi/full/10.1177/0263617418779738 https://journals.sagepub.com/doi/full/10.1177/0263617418779738 https://journals.sagepub.com/doi/full/10.1177/0263617418779738 https://journals.sagepub.com/doi/full/10.1177/0263617418779738 https://journals.sagepub.com/doi/full/10.1177/0263617418779738 https://journals.sagepub.com/doi/full/10.1177/0263617418779738 h. m. ibrahim and r. h. salman / iraqi journal of chemical and petroleum engineering 23,1 (2022) 31 41 40 [35] g. chen, “electrochemical technologies in wastewater treatment”, separation and purification technology, vol. 38, no. (1), pp. 11–41, 2004. [36] m. panizza, and g. cerisola, “direct and mediated anodic oxidation of organic pollutants”, chemical reviews, vol. 109, no. (12), pp. 6541–6569, 2009. [37] j. p. de p. barreto, e. v. dos santos, m. m. oliveira, d. r. da silva, j. f. de souza, and c. a. martínez-huitle, “electrochemical mediated oxidation of phenol using ti/iro2 and ti/pt-sno2-sb2o5 electrodes”, journal of electrochemical science and engineering, vol. 4, no. (4), pp. 259–270, 2014. [38] a. s. naje, and s. a. abbas, “combination of electrocoagulation and electro-oxidation processes of textile wastewaters treatment”, civil and environmental research, vol. 3, no. (13), pp. 61–73, 2013. [39] h. rubí-juárez, c. barrera-díaz, i. linareshernández, c. fall, b. bilyeu, “a combined electrocoagulation-electrooxidation process for carwash wastewater reclamation”, int. j. electrochem. sci., vol. 10, pp. 6754 – 6767, 2015. [40] s. s. alkurdi, and a. h. abbar, “removal of cod from petroleum refinery wastewater by electro coagulation process using ss /al electrodes”, iop conf. ser.: mater. sci. eng., 870012052, 2020. [41] r. b. a. souza, and l. a. m. ruotolo, “electrochemical treatment of oil refinery effluent using boron-doped diamond anodes”, journal of environmental chemical engineering, vol. 1, no. (3), pp. 544–551, 2013. [42] a. n. ghanim, and a. s. hamza, “evaluation of direct anodic oxidation process for the treatment of petroleum refinery wastewater”, journal of environmental engineering, vol. 144, no. (7), 2018. [43] i. linares-hernández, c. barrera-díaz, b. bilyeu, p. juárez-garcíarojas, and e. camposmedina, “a combined electrocoagulationelectrooxidation treatment for industrial wastewater”, journal of hazardous materials, vol. 175, no. (1–3), pp. 688–694, 2010. [44] h. liu, x. zhao, and j. qu, “electrocoagulation in water treatment, electrochemistry for the environment”. springer new york, 2010, doi: 10.1007/978-0-387-68318-8. [45] o. scialdone, s. randazzo, a. galia, and g. silvestri, “electrochemical oxidation of organics in water: role of operative parameters in the absence and in the presence of nacl”, water research, vol. 43, no. (8), pp. 2260–2272, 2009. [46] i. d. santos, m. dezotti, and a. j. b. dutra, “electrochemical treatment of effluents from petroleum industry using a ti/ruo2 anode”, chemical engineering journal, vol. 226, pp. 293–299, 2013. [47] y. yavuz, a. s koparal, and ü. b. öğütveren, ‘treatment of petroleum refinery wastewater by electrochemical methods”, desalination, vol. 258, pp. 201–205, 2010. [48] y. h.cui, y. j., feng, and x. y. li, “kinetics and efficiency analysis of electrochemical oxidation of phenol: influence of anode materials and operational conditions”, chemical engineering & technology, vol. 34, no. (2), pp. 265–272, 2010. https://www.sciencedirect.com/science/article/abs/pii/s1383586603002636 https://www.sciencedirect.com/science/article/abs/pii/s1383586603002636 https://www.sciencedirect.com/science/article/abs/pii/s1383586603002636 https://pubs.acs.org/doi/full/10.1021/cr9001319 https://pubs.acs.org/doi/full/10.1021/cr9001319 https://pubs.acs.org/doi/full/10.1021/cr9001319 https://pubs.acs.org/doi/full/10.1021/cr9001319 https://hrcak.srce.hr/130225 https://hrcak.srce.hr/130225 https://hrcak.srce.hr/130225 https://hrcak.srce.hr/130225 https://hrcak.srce.hr/130225 https://hrcak.srce.hr/130225 http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.852.736&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.852.736&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.852.736&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.852.736&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.852.736&rep=rep1&type=pdf http://electrochemsci.org/papers/vol10/100806754.pdf http://electrochemsci.org/papers/vol10/100806754.pdf http://electrochemsci.org/papers/vol10/100806754.pdf http://electrochemsci.org/papers/vol10/100806754.pdf http://electrochemsci.org/papers/vol10/100806754.pdf https://iopscience.iop.org/article/10.1088/1757-899x/870/1/012052/meta https://iopscience.iop.org/article/10.1088/1757-899x/870/1/012052/meta https://iopscience.iop.org/article/10.1088/1757-899x/870/1/012052/meta https://iopscience.iop.org/article/10.1088/1757-899x/870/1/012052/meta https://www.sciencedirect.com/science/article/abs/pii/s2213343713000821 https://www.sciencedirect.com/science/article/abs/pii/s2213343713000821 https://www.sciencedirect.com/science/article/abs/pii/s2213343713000821 https://www.sciencedirect.com/science/article/abs/pii/s2213343713000821 https://www.sciencedirect.com/science/article/abs/pii/s2213343713000821 https://ascelibrary.org/doi/abs/10.1061/(asce)ee.1943-7870.0001389 https://ascelibrary.org/doi/abs/10.1061/(asce)ee.1943-7870.0001389 https://ascelibrary.org/doi/abs/10.1061/(asce)ee.1943-7870.0001389 https://ascelibrary.org/doi/abs/10.1061/(asce)ee.1943-7870.0001389 https://www.sciencedirect.com/science/article/abs/pii/s0304389409017154 https://www.sciencedirect.com/science/article/abs/pii/s0304389409017154 https://www.sciencedirect.com/science/article/abs/pii/s0304389409017154 https://www.sciencedirect.com/science/article/abs/pii/s0304389409017154 https://www.sciencedirect.com/science/article/abs/pii/s0304389409017154 https://www.sciencedirect.com/science/article/abs/pii/s0304389409017154 https://link.springer.com/chapter/10.1007/978-0-387-68318-8_10 https://link.springer.com/chapter/10.1007/978-0-387-68318-8_10 https://link.springer.com/chapter/10.1007/978-0-387-68318-8_10 https://link.springer.com/chapter/10.1007/978-0-387-68318-8_10 https://www.sciencedirect.com/science/article/abs/pii/s0043135409001079 https://www.sciencedirect.com/science/article/abs/pii/s0043135409001079 https://www.sciencedirect.com/science/article/abs/pii/s0043135409001079 https://www.sciencedirect.com/science/article/abs/pii/s0043135409001079 https://www.sciencedirect.com/science/article/abs/pii/s0043135409001079 https://www.sciencedirect.com/science/article/abs/pii/s1385894713005585 https://www.sciencedirect.com/science/article/abs/pii/s1385894713005585 https://www.sciencedirect.com/science/article/abs/pii/s1385894713005585 https://www.sciencedirect.com/science/article/abs/pii/s1385894713005585 https://www.sciencedirect.com/science/article/abs/pii/s0011916410001487 https://www.sciencedirect.com/science/article/abs/pii/s0011916410001487 https://www.sciencedirect.com/science/article/abs/pii/s0011916410001487 https://www.sciencedirect.com/science/article/abs/pii/s0011916410001487 https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.201000192 https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.201000192 https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.201000192 https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.201000192 https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.201000192 h. m. ibrahim and r. h. salman / iraqi journal of chemical and petroleum engineering 23,1 (2022) 31 41 41 دراسة أمثلية معالجة مياه الصرف الصحي المطروحة من المصافي النفطية بوساطة عمليتي األكسدة و التخثير الكهربائيتين المتتاليتين هند ابراهيم و رشا حبيب سلمان جامعة بغدادمكلية الهندسة الخالصة ( بصورة متوالية لتقليل بعض ec-eoالتخثير واألكسدة الكهربائيتين )في هذه الدراسة ، تم استخدام عمليتي الملوثات الرئيسية في مياه الصرف الصحي الحقيقية ، مثل المواد العضوية )معبر عنها بالطلب الكيميائي (( ، والعكورة. تم جمع مياه الصرف الصحي المستخدمة في هذه الدراسة من شركة مصفى codلألوكسجين ) ( alالمتتالية باستخدام الكرافيت واأللمنيوم ) ec-eoالعراق. تمت دراسة أداء عمليات -في بغدادالوسط للحصول taguchi( ككاثود. تم استخدام نهج التصميم التجريبي .st.stكأقطاب أنود والفوالذ المقاوم للصدأ ) الحاجة الكيميائية لألوكسجين كاستجابة رئيسية. بدًءا من codعلى أفضل الظروف التجريبية للحد من قيمة cod ( تأثيرات كثافة التيار 600البالغ ،)مغ/لتر(c.d.)( 10-204( ، ودرجة الحموضة )2مللي أمبير/سم غم/لتر( تمت دراستها. 2,5 – 1,5ساعات(، وتركيز كلوريد الصوديوم ) 4-2(، والزمن )10 ة التيار و زمن التحلل الكهربائي و تركيز كلوريد تزداد بزيادة كثاف %cod reأظهرت النتائج أنه قيمة مللي 20. كانت أفضل الظروف لمعالجة هذه المياه العادمة هي: ) phالصوديوم و بأنخفاض قيمة غم/لتر(. في هذه 2,5ساعات(، و تركيزكلوريد الصوديوم 4(، والزمن )4( ، ودرجة الحموضة )2أمبير/سم ( بحوالي encمع استهالك الطاقة الكهربائية ) cod٪ من 98,12الظروف ، تم تحقيق ما يقارب من لهما تأثير أعلى على أداء إزالة phو .c.dأن anovaكيلوواط.ساعة /مترمكعب. كشفت نتيجة 62,04 .%cod reلها تأثير طفيف على .nacl concالمواد العضوية ، في حين أن الزمن و الصحي من المصافي, التخثيرالكهربائي, األكسدة الكهربائية, طريقة تاكوشي. الكلمات الدالة: النفطي, مياه الصرف available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol. 24 no.1 (march 2023) 51 – 63 eissn: 2618-0707, pissn: 1997-4884 *corresponding author: name: zainab m. issa, email: zainab.issa1607m@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. electrosorption of hexavalent chromium ions by mno2/carbon fiber composite electrode: analysis and optimization of the process by box-behnken design zainab m. issa a, *, rasha h. salman a, and prashant basavaraj bhagawati b a chemical engineering department, college of engineering, university of baghdad, baghdad, iraq b college of engineering and technology, ashta, maharashtra, india abstract a nano manganese dioxide (mno2) was electrodeposited galvanostatically onto a carbon fiber (cf) surface using the simple method of anodic electrodeposition. the composite electrode was characterized by field emission scanning electron microscopy (fesem), and x-ray diffraction (xrd). very few studies investigated the efficiency of this electrode for heavy metals removal, especially chromium. the electrosorption properties of the nano mno2/cf electrode were examined by removing cr(vi) ions from aqueous solutions. nacl concentration, ph, and cell voltage were studied and optimized using the box-behnken design (bdd) to investigate their effects and interactions on the electrosorption process. the results showed that the optimal conditions for the removal of cr(vi) ions were a cell voltage of 4.6 v, ph of 2 and nacl concentration of 1.5 g/l. this work indicated that mno2/cf electrode was highly effective in removing cr(vi) ions and the bbd approach was a feasible and functional method for evaluating the experimental data. keywords: electrosorption process, hexavalent chromium ions, composite electrode, electrodeposition, nanostructured mno2, box-behnken design. received on 13/12/2022, received in revised form on 24/01/2023, accepted on 25/01/2023, published on 30/03/2023 https://doi.org/10.31699/ijcpe.2023.1.7 1introduction development of industries to serve human needs increases as the population grows. this rise has a negative impact on the environment, human health, and aquatic life [1, 2]. heavy metals are a source of pollution even at trace levels, with toxicity ranging from high to carcinogenicity due to repeated exposure [3, 4]. metals are extremely dangerous since they are not biodegradable and may concentrate in biological organisms, getting denser as they go into the food chain. [5]. in industrial wastewater treatment, toxic heavy metals of particular concern are zinc, copper, nickel, mercury, cadmium, lead, and chromium [2, 6]. chromium is a primary concern for the environmental protection agency (epa) especially when present in the hexavalent form, because of its widespread application and high toxicity [7]. in industry, chromium compounds are utilized in electroplating, leather tanning, metal polishing, chemical manufacturing, pigments, electronic and electrical equipment [8]. chromium typically enters the aquatic environment in two forms: cr(iii) and cr(vi). in general, cr(vi) is more dangerous than cr (iii). furthermore, cr(vi) is a strong oxidant that may be absorbed by the skin and is highly mobile in soeil and aquatic systems [9, 10]. the acceptable limits of cr(vi) and total chromium (tcr) released to surface water should be less than 0.05 and 0.1 mg/l, respectively, according to the united states environmental protection agency (usepa) [2, 11]. many strategies for removing cr(vi) ions, including ion exchange, chemical precipitation, coagulation, chemical reduction, adsorption [4], and capacitive deionization (cdi) or electrosorption considered efficient methods [12]. electrosorption is an electrochemical method of removing metals under the influence of an electric field. cdi is an electrosorption process in which ions in an aqueous solution are adsorbed on the electrical double layers of porous electrodes after being exposed to a lowvoltage electric field [13, 14]. when compared to other existing desalination systems, cdi offers the benefits of being environmentally sustainable, utilizing less energy and having lower running costs than other desalination methods, and being simpler to regenerate and maintain [12]. the most important component of any electrochemical system is the electrode material [15]. carbon aerogel, activated carbon, carbon fiber, ordered mesoporous carbon, carbon nanotubes, and graphene are examples of nanoporous carbon materials that have been suitable electrodes for the electrosorption process [16], [17]. carbon fiber (cf) is a porous kind of activated carbon that has a strong electrosorptive capability owing to its larger specific surface area [14]. carbon fiber has gotten attention because of its potentially inexpensive manufacturing cost, significant uptake capacity, high strength, high electrical conductivity, high stability, and consistent pore size [18, 19]. the capacitance of the http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:zainab.issa1607m@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2023.1.7 z. m. issa et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 51 63 52 electrosorption process is a strong indicator of how effectively porous materials remove ions [20]. the electrochemical storing mechanism of metal ions in capacitive deionization operates in the same manner as an electrochemical supercapacitor. it is based on either the electrical double-layer capacitance (edl) from pure electrostatic adsorption when porous carbon materials are used or the pseudo capacitance from reversible and fast faradic reactions when redox-active materials (pseudo capacitive materials) are used [21]. in surface-redox pseudo capacitive materials, ions are electrochemically adsorbed onto the surface of a material accompanied by a faradaic charge transfer [22]. an example of pseudo capacitive material is manganese dioxide, mno2 stores ions by the surface redox reaction between oxidation states of mn4+ and mn3+. the mechanism is based on the adsorption of electrolyte cations (c+) onto the surface of mno2 as shown in eq. 1 [23]: (𝑀𝑛𝑂2)𝑠𝑢𝑟𝑓𝑎𝑐𝑒 + 𝐶 + + 𝑒− ↔ (𝑀𝑛𝑂2 − 𝐶 +)𝑠𝑢𝑟𝑓𝑎𝑐𝑒 (1) where: c+ represents an alkali metal cation (h+, li+, na+, k+) in the electrolyte. electrochemical pseudo capacitors could be constructed from a wide range of materials, including conducting polymers, noble metal oxides which including ruo2 and iro2, and transition metal oxides like mno2, nio, co2o3, feo, tio2, sno2, v2o5 and moo [24]. transition metal oxides offer pseudo-capacitance behavior, with a higher specific capacitance than electrical double layers of carbonaceous materials due to the faradaic redox reaction in the active materials. these active materials are loaded onto the surface of carbon to enhance the electrosorption capability of the carbon materials [25]. mno2 is a perspective electrode material for supercapacitors among metal oxide compounds because of its low cost, environmentally friendly nature, and relatively high theoretical pseudo capacitance value, 1370 f.g-1, which is much greater than that of carbon-based materials. so, a lot of interest has been focused on developing mno2-based materials as an electrode for electrochemical supercapacitors and as effective adsorbents to remove heavy metals from water. numerous investigations have focused on connecting mno2 to the surface of carbonaceous materials, such as activated carbon, carbon fibers, carbon nanotubes, and graphene-based materials, to overcome this difficulty [26, 27]. currently, relatively few articles have explored heavy metal removal by electrosorption onto mno2/cf electrodes, and no previous works have investigated the applicability of this electrode for chromium ion removal by electrosorption. the current study targets to synthesize and characterize mno2/carbon fiber electrode, the produced electrode's performance in electrosorption of cr(vi) ions from an aqueous solution was examined by changing three variables cell voltage, ph, and ionic strength (nacl concentration). the effect of these selected operational factors and their interactions on removal efficiency were studied and optimized using the response surface methodology and the box-behnken design. 2experimental work 2.1. reagents and chemicals all reagents were of analytical grade and were utilized without additional purification. for the electrodeposition of mno2, manganese (ii) sulfate monohydrate (mnso4.h2o) (98% purity, thomas baker) and sulfuric acid (h2so4) (98% purity, alpha chemika, india) were used in the electrolytic solution. for the experiment of chromium ions removal, potassium dichromate (k2cr2o7) (99% purity, alpha chemika, india), sodium chloride (nacl) (99% purity, himedia laboratories pvt.ltd.), sodium hydroxide (naoh) (98% purity, alpha chemika, india), diphenylcarbazide (c13h14n4o, fluka chemika, switzerland), and hno3 (69% purity, central drug house (p) ltd.) were utilized. all solutions were prepared with deionized water of 5µs/cm conductivity. the pure carbon fiber purchased form jiaxing agg composites co. ltd., china. fig. 1 shows the fesem-edx characterization of the purchased pure carbon fiber electrode. fesem analysis depicts the smooth surface of pure carbon fiber electrode as shown in fig. 1a and fig. 1b. edx analysis demonstrates that 86.76% of electrode material is composed of carbon as shown in the fig. 1c. 2.2. preparation of electrodes to synthesize nanostructured mno2, experiments of anodic electrodeposition of mno2 onto cf were carried out utilizing commercial cf as a substrate and current collector. a rectangular slice of cf (16.5cm × 5 cm) was activated for 30 minutes at 80°c with 5% hno3, then cleaned and stored in distilled water. the electrodeposition of mno2 onto cf was carried out galvanostatically for 4 h at a current density of (0.3 ma/cm2) using a regulated dc power supply (uni-t: utp3315tf-l). a 2l beaker containing 1.8l of aqueous solution (0.64m h2so4 + 0.35m mnso4) was used as the electrolytic solution. the solution was agitated and retained at 90 ℃ by a hot plate magnetic stirrer (heidolph: mr hei-standard, germany). three electrodes were used; an activated cf piece served as an anode, and two graphite served as counter electrodes. after the completion electrodeposition process, the composite electrode of mno2/cf was washed and rinsed multiple times with distilled water and then dried. the prepared electrode would be used later in the electrosorption process of chromium ions. the electrodeposition experimental setup is schematically shown in fig. 2. 2.3. characterization and analysis the crystal structure of deposited mno2 films were characterized by x-ray diffraction (xrd, phillips: pw1730, usa), and the diffraction data were collected over 2θ. cu-kα radiation utilized as the x-ray source with λ = 1.54056 ̊a. the morphology and composition of the prepared mno2/cf electrode was tested using field z. m. issa et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 51 63 53 emission scanning electron microscopy (fesem, tescan mira3, czech) equipped with an energy dispersive x-ray spectrometry (edx ) analyzer at an operating conditions of 25kv and 100𝜇𝐴. the amount of cr(vi) ions that remained in the aqueous solution was determined at the maximum wavelength of 540 nm using a uv spectrophotometer (thermo uvspectrophotometer, usa). in acidic environments, diphenylcarbazide interacts with cr(vi) ions to generate a dark violet-colored complex [28, 29]. fig. 1. characterization of the pure carbon fiber electrode (a, b) fesem (c) edx fig. 2. setup scheme of the electrodeposition process 2.4. electrosorption experiment the electrosorption process was tested in a batch experiment consisting of a glass beaker comprising of an aqueous solution of 0.8l with a constant starting cr(vi) ions concentration of 100 ppm to study the electrosorption characteristics of the nanostructured mno2/carbon fiber. the cdi system used two electrodes: a working electrode of mno2/cf and counter electrode of stainless steel plate (17cm x 5 cm x 3 mm), with a 1.5cm space between the 1 2 3 4 5 6 7 8 9 10 kev 0 2 4 6 8 10 12 14 16 cps/ev c o n mn mn z. m. issa et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 51 63 54 electrodes. the aqueous solution was agitated with a constant stirring rate of 250 rpm during the experiment using a hot plate magnetic stirrer (heidolph: mr heistandard, germany) to guarantee ionic diffusion, and all tests were carried out at 25°c ±1 room temperature. a direct-current power supply was coupled to the electrodes to supply the electrical current. before each experiment, the ph was adjusted to the desired value by adding 1m of sodium hydroxide or 1m of sulfuric acid, and it was detected with a ph meter equipment (hanna instrument, phep: hi98107). eqs. 2 and 3 were used to compute the removal efficiency of cr(vi) ions and the equilibrium adsorption capacity qe (mg/g), respectively [17]: 𝑅𝑒% = (𝐶0−𝐶𝑒) 𝐶𝑜 × 100 (2) 𝑞𝑒 = 𝐶𝑜−𝐶𝑒 𝑚 × 𝑣 (3) where 𝐶0 (mg/l) and 𝐶𝑒 (mg/l) are the initial and equilibrium chromium ion concentrations in the solution, respectively, m is the total mass of the electrode, and v is the volume of solution. the cdi experimental setup is schematically shown in fig. 3. fig. 3. schematic diagram of the electrosorption setup 2.5. preliminary experiment to determine the equilibrium time required for the mno2/carbon fiber electrodes to reach their saturation point, two preliminary batch electrosorption experiments were performed at ph 2, 4.1v, and 1g/l nacl concentration with two initial concentrations (100 and 150 ppm of cr ions). these two experiments were carried out before the set of experiments determined by the experimental design. 2.6. experimental design response surface methodology (rsm) is a software program that consists of a set of a statistical and mathematical methods that are considered to be very effective for modeling and analyzing in which a response of interest is affected by numerous variables in order to investigate the optimal conditions to achieve the desired response [30]. a statistical design called box-behnken design (bbd) was used in this study to optimize and investigate the impact of specified operating variables on cr(vi) ions removal using the electrosorption method. a boxbehnken design of three-factors with three levels would result in a set of 15 tests with three replicates at the center point [31]. the factors were ph (x1), nacl concentration (x2), and cell voltage (x3), with the removal efficiency (y) of cr(vi) ions being the response. generally, each variable in the box-behnken design has three levels as coded values, denoted by the numbers -1, 0 and 1. levels 1 and -1 represent the maximum and minimum values for each input variable, respectively, while level 0 represents the variable's center value [17]. table 1 displays the variables of the process with their coded and real values. according to eq. 4, the box-behnken design establishes a model of a polynomial second-order equation to analyze the influence of the specified variables on the produced response: 𝑌 = 𝛽𝑜 + ∑ 𝛽𝑖 𝑘 𝑖=1 𝑋𝑖 + ∑ 𝛽𝑖𝑖 𝑘 𝑖=1 𝑋𝑖 2 + ∑ ∑ 𝛽𝑖𝑗 𝑘 𝑗>1 𝑘 𝑖=1 𝑋𝑖 𝑋𝑗 (4) as previously stated, y represents the achieved response (removal efficiency of cr(vi) ions), 𝛽𝑜 is the intercept term, 𝛽𝑖 is the linear term, 𝛽𝑖𝑖 is the quadratic term, and 𝛽𝑖𝑗 is the interaction term, xi, xj, …, xk are the process input variables [32]. z. m. issa et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 51 63 55 table 1. coded and real values of variables run blk coded values real values x1 x2 x3 ph nacl voltage 1 1 0 -1 1 4 0.5 4.6 2 1 1 0 1 6 1 4.6 3 1 0 0 0 4 1 4.1 4 1 0 0 0 4 1 4.1 5 1 0 1 -1 4 1.5 3.6 6 1 1 0 -1 6 1 3.6 7 1 0 -1 -1 4 0.5 3.6 8 1 -1 0 1 2 1 4.6 9 1 0 1 1 4 1.5 4.6 10 1 0 0 0 4 1 4.1 11 1 -1 1 0 2 1.5 4.1 12 1 -1 -1 0 2 0.5 4.1 13 1 -1 0 -1 2 1 3.6 14 1 1 -1 0 6 0.5 4.1 15 1 1 1 0 6 1.5 4.1 3result and discussion 3.1. characterization of mno2/carbon fiber composite electrode x-ray diffraction (xrd) analysis was used to determine the presence of deposited manganese dioxide nanoparticles on the carbon fiber surface, as well as their phases and crystal structure at 0.3 ma/cm2, applied current density, and 0.64 m h2so4 concentration. fig. 4 shows the patterns of xrd analysis for mno2 nanostructured electrodeposited onto the carbon fiber surface. the intensity of most diffraction peaks was for nanostructured mno2 with two diffraction peaks of pure carbon fiber, positioned approximately at 24o and 43o, which correspond to the amorphous carbon (002) and (100) lattice planes [23]. all of the electrodeposited mno2 diffraction peaks attributed to the pure phase of orthorhombic γmno2, and the peaks correspond with the standard jcpds card (no.14-0644) [33]. the diffraction peaks were at 2θ (34.2o, 37.16o, 38.24o, 42.44o, 44.04o, 56.32o, 57.8o, 61.69o, 65.24o, 69.08o, 71.96o, 75.72o, and 78.88o) as shown in fig. 4. numerous studies have shown that electrode efficiency, capacity, and stability are greatly influenced by electrode morphology [34]. mno2 nanostructures electrodeposited on the surface of carbon fiber have the morphology of spherical brushes consisting of straight nanorods grown normally to the surface of carbon fiber, this has also observed by xie et al. [35] and illustrated in fig. 5. these several nanorods have approximately a smaller diameter (35.11 nm), they are merged to form a smooth and thin film. this film has a uniform structure and high capacity as a result of its large surface area. furthermore, rod-like shapes can supply both ions and electrons with short diffusion channel lengths as well as adequate porosity for electrolyte penetration, resulting in rapid charge/discharge rates [36]. fig. 4. results of xrd analysis of mno2 nanoparticles deposited on carbon fiber prepared at (0.3ma/cm 2, 0.64m h2so4) fig. 5. results of fesem image of mno2 nanoparticles deposited on carbon fiber prepared at (0.3ma/cm 2, 0.64m h2so4) with different magnifications (a) 10 𝜇𝑚, (b) 500nm and (c) 200 nm z. m. issa et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 51 63 56 3.2. result of preliminary experiment at ph = 2, cell voltage = 4.1v, and nacl concentration = 1g/l, two preliminary experiment were accomplished. adsorption for mno2/carbon fiber electrode was allowed to proceed for up to 5 h with periodic measurements, and it was revealed that adsorption for 4 h was sufficient to achieve equilibrium with high removal efficiency as shown in fig. 6. since the equilibrium time for the two concentrations (100 and 150 ppm) were the same, 100 ppm concentration has been used as the initial concentration in all experiments that have been studied in the experimental design. mno2/carbon fiber electrode could accelerate the electrosorption process to complete in 3 h according to its faradic-capacitive behavior. while due to the capacitive behavior of carbon fiber electrode, the electrosorption process require 4 h to reach the equilibrium time, that result has been achieved in our previous study [37]. fig. 6. the removal efficiency of cr(vi) ions vs. time on mno2/carbon fiber electrode at conditions of ph 2, 4.1v, and 1 g/l nacl concentration 3.3. analysis for electrosorption process using response surface methodology 3.3.1. the box–behnken model table 2 displays the actual values achieved from the experimental work as well as the predicted values measured using rsm methods, which illustrate the electroporation process's response to the chromium ion removal efficiency [38]. minitab-19 software was used to analyze experimental data. to establish the regression equation, the experimental data were fitted into a secondorder model. equation 5 gives the final empirical equation that shows the relation between the removal efficiency of cr(vi) ions and the three specified variables in terms of coded units: 𝑌% = 245.0 − 39.42𝑋1 − 115.2𝑋2 − 38.0𝑋3 + 3.223𝑋12 + 5.66𝑋22 + 2.56𝑋32 + 1.492𝑋1 ∗ 𝑋2 + 1.829𝑋1 ∗ 𝑋3 + 28.59𝑋2 ∗ 𝑋3 (5) where y represents the removal % of cr(vi) ions, i.e. the response, and the operational variables are ph (x1), nacl concentration (x2), and cell voltage (x3). the analysis of variance (anova) based on the bbd was studied to evaluate the significance and suitability of the recommended polynomial quadratic models [39]. the degree of freedom (dof), percentage contribution%, sum of squares (ss), mean of squares (ms), adjusted sum of squares (adj. ss), adjusted mean of squares (adj. ms), fvalue, and p-value were used to specify the anova analysis. table 3 displays the anova results. anova provides the percentage contribution for each variable, as shown in table 3. the greater a variable's percentage contribution, the greater its impact to the final results. any small change in its value will have a significant impact on the reaction [30]. anova analysis shows that the contributions of ph, nacl concentration and cell voltage are the same approximately, which mean that their impact on the response were convergent. the contribution of linear term was 71.48%, while the terms of square and two-way interaction have contributed with 20.42% and 7.52%, respectively. the model is highly significant, as demonstrated by lower p-values (p model = 0.000) and higher f-values (f model = 96.06). the ratio of mean square model (ms) to the error mean square represent the f-value. the higher the ratio, the higher the f-value [40]. in the model, the probability value (p-value) is used to evaluate statistically significant effects. a p-value of less than 0.05 refers that the impact of the variable is statistically significant at a 95% confidence level [41]. analysis of f-value and p-value indicated that ph (x1), nacl (x2), voltage (x3) and ph*ph (x1*x1) terms are the most controlling terms in the model. furthermore, high determination coefficient (r2) which equal to 99.42% indicating good model fitting with experimental data. 3.3.2. main effect plots the relationship between the response and the selected operational variable could be illustrated using the main effect plots. fig. 7 demonstrates the impacts of ph solution, cell voltage, and ionic strength on the removal efficiency of cr(vi) ion in the electrosorption process using mno2/carbon fiber electrode, respectively. the maximum removal efficiency was observed when the ph value was reduced to 2. the influence of ph was investigated from 2 to 6. fig. 7 also demonstrates an obvious improvement in removal % when nacl concentration increases from 0.5 to 1.5 g/l and applied voltage increases from 3.6 to 4.6v. the experimental results reveal that reducing the ph value improves the reduction of cr(vi), whereas increasing the ph decreases the reduction of cr(vi) due to the smaller amount of h+ ion in the solution [42]. because the presence of h+ ions induces the cathodic reduction of cr(vi) to cr(iii) under highly acidic environment, as indicated in eqs. 6 and 7 [43]: cr2o7 2+ 8h+ + 6e→ cr2o3 + 4h2o e°= 1.33 v (6) hcro4 + 7h+ + 3e→ cr3+ + 4h2o e°=1.35 v (7) z. m. issa et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 51 63 57 table 2. experimental results of bbd for cr(vi) ions removal run blk ph nacl conc. voltage re% ac(mg/g) x1 x2 x3 act.% pred.% 1 1 4 0.5 4.6 64.510 64.493 83.23871 2 1 6 1 4.6 83.717 85.324 108.0219 3 1 4 1 4.1 69.901 69.804 90.19484 4 1 4 1 4.1 69.807 69.804 90.07355 5 1 4 1.5 3.6 64.914 64.931 83.76 6 1 6 1 3.6 63.027 62.768 81.32516 7 1 4 0.5 3.6 58.040 59.888 74.89032 8 1 2 1 4.6 99.990 100.249 129.0194 9 1 4 1.5 4.6 99.970 98.122 128.9935 10 1 4 1 4.1 69.703 69.804 89.93935 11 1 2 1.5 4.1 99.990 101.580 129.0194 12 1 2 0.5 4.1 85.469 85.227 110.2826 13 1 2 1 3.6 86.615 85.008 111.7613 14 1 6 0.5 4.1 65.251 63.661 84.19484 15 1 6 1.5 4.1 85.739 85.981 110.631 table 3. analysis of variance for cr(vi) removal using mno2/carbon fiber electrode source dof seq. ss contribution adj. ss adj.ms f-value p-value model 9 2994.22 99.42% 2994.22 332.691 96.05 0.000 linear 3 2152.61 71.48% 2152.61 717.537 207.15 0.000 ph 1 690.62 22.93% 690.62 690.619 199.38 0.000 nacl 1 747.74 24.83% 747.74 747.742 215.87 0.000 voltage 1 714.25 23.72% 714.25 714.250 206.20 0.000 square 3 615.04 20.42% 615.04 205.015 59.19 0.000 ph*ph 1 606.60 20.14% 613.83 613.834 177.21 0.000 nacl*nacl 1 6.93 0.23% 7.39 7.392 2.13 0.204 voltage*voltage 1 1.51 0.05% 1.51 1.512 0.44 0.538 2-way interaction 3 226.57 7.52% 226.57 75.523 21.80 0.003 ph*nacl 1 8.90 0.30% 8.90 8.901 2.57 0.170 ph*voltage 1 13.38 0.44% 13.38 13.377 3.86 0.107 nacl*voltage 1 204.29 6.78% 204.29 204.290 58.98 0.001 error 5 17.32 0.58% 17.32 3.464 lack-of-fit 3 17.30 0.57% 17.30 5.766 587.86 0.002 pure error 2 0.02 0.00% 0.02 0.010 total 14 3011.54 100.00% model summery s r2 r2 (adj.) press r2 (pred.) aicc bic 1.86113 99.42% 98.39% 276.836 90.81% 154.72 74.51 fig. 7. main effect plot for cr(vi) ions removal using mno2/carbon fiber electrode furthermore, at higher ph levels, the following reaction occurs (equation 8), and chromium could also generate hydroxide in the form of cr(oh)3. cr3+ + 3oh → cr(oh)3 (8) this reaction occurs quickly at higher ph levels and prevents cr(vi) reduction [43]. z. m. issa et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 51 63 58 the positive influence of increasing nacl concentration on removal efficiency could be attributed to an increases in system electric current, ion flow, and redox reaction. however, further increases in nacl concentration may result in inhabitation behavior, lowering or even suppressing chromium adsorption due to competing forces [44]. these effects have been examined because both natural water and wastewater typically include ions that can affect and compete with the adsorption of other ions [45]. the effects of increasing the applied voltage in this figure reveals that increasing the applied voltage has a significant effect on the efficiency of cr(vi) ions removal. an increase in electron flow velocity at high applied voltage values leads to an increase in electrostatic attraction and as a result the removal efficiency increase [46]. 3.3.3. effect of interactive parameters fig. 8a depicts the interaction between ph value and nacl concentration and their impact on removal efficiency. as seen in the surface plot, increasing the ph value causes an obvious decrease in removal efficiency at 0.5 g/l nacl concentration, whereas the decrease in removal efficiency is less at 1.5 g/l nacl concentration. furthermore, at ph 2, greater removal efficiency is obtained by increasing nacl concentration to 1.5 g/l, however at ph 4, there is a significant reduction followed by a slight elevation at ph 6. the related contour plot shows a dark red region that represents the greatest removal effectiveness at ph 2 and nacl concentration ranges of 0.8 to 1.5 g/l. the interaction between ph value and cell voltage and their impact on removal efficiency is depicted in fig. 8b, which shows that at ph= 2, higher removal efficiency was achieved when the cell voltage was 4.6v, followed by a gradual decrease in removal efficiency when the applied voltage was reduced to 3.6v. at a cell voltage of 3.6v, the fig. reveals a severe reduction in removal efficiency as the ph value increases, and this decrease appears to be reduced as the cell voltage rises from 3.6 to 4.6v. according to the related contour plot, the area of highest removal efficiency values appears to be confined to cell voltages of (3.9-4.5v) and ph values of 2. the effects of cell voltage and nacl content on removal efficiency are depicted in fig. 8c. at 1.5 g/l nacl concentration, the removal efficiency of cr(vi) ions increases linearly and reaches its maximum when the cell voltage is increased from 3.6 to 4.6v, however there is no significant influence of cell voltage at 0.5 g/l nacl concentration. at a cell voltage of 3.6v, increasing nacl concentration has no influence on removal efficiency, however at a cell voltage of 4.6v, increasing nacl concentration from 0.5 to1.5 g/l increases removal efficiency. the resulting contour plot shows that the greatest removal efficiency values are found in the cell voltage range of 4.3-4.6v and the nacl concentration range of 1.28-1.5g/l. 3.3.4. optimization using desirability function and conformation test to analyze the results and attain the optimal conditions for reducing cr(vi) ions from an aqueous solution, optimization utilizing overall desirability was devised. the desirability function offers information on the quality and acceptability of the process [47]. the function represent a mathematical strategy for simultaneously determining the optimum values of input variables and output (response) by applying the optimum input variable levels [48]. when the desirability function ranges from 0 to 1, the removal efficiency is maximized. if the desirability value is 0, the proposed value is unfavorable. if it is 1, it signifies that the system's response has improved and it is stable [49]. to achieve this purpose, the three examined variables were estimated on a specified range of values, with the response aiming for the maximum. the optimization results for mno2/carbon fiber electrode are provided in table 4, with the model having a desirability function of (1). two conformation experiments were performed using the program's recommended optimal parameters. the results of these experiments are intended to fit within the parameters determined by the optimization analysis. table 5 shows the confirmation test results on optimally specified variables. the average removal efficiency was 99.98%, which was extremely near to the suggested one. table 4. optimization of system variables for the maximum removal of cr(vi) using mno2/carbon fiber electrode response goal lower target upper weight importance cr removal% maximum 58.04 99.99 1 1 solution of parameters multiple response prediction ph nacl voltage cr removal% (fit) composite desirability se fit 95% ci 95% pi 2 1.5 4.6 116.986 1 2.20 (111.33, 122.64) (109.58, 124.39) table 5. confirmation tests of cr(vi) ions removal using mno2/ carbon fiber electrode run ph nacl concentration cell voltage re% actual average ac (mg/g) 1 2 1.5 4.6 99.99% 99.98% 129.0194 2 2 1.5 4.6 99.98% 128.9806 z. m. issa et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 51 63 59 fig. 8. response surface plot and contour plot for the effect of (a) ph and nacl concentration (g/l), (b) ph and cell voltage (v), and (c) nacl concentration (g/l) and cell voltage (v) on cr(vi) removal using mno2/ carbon fiber electrode 4conclusion a manganese dioxide/cf composite electrode has been efficiently synthesized by anodic electrodeposition process at 0.64 m h2so4 concentration, 0.35 m mnso4 concentration and 0.3 ma/cm2 current density. xrd and fesem analysis confirm the formation of γmno2 nanorods with diffraction peaks of sharp intensity and smaller diameter of about 35.11nm. the electrosorption ability of mno2/carbon fiber electrode to adsorb cr(vi) ions from an aqueous solution were investigated and the result showed a high removal efficiency of 99.99% and adsorption capacity of 129.0194 mg/g at concentration of 100 mg/l. from response surface methodology analysis, it has been detected that nacl concentration has the major effect on removal efficiency with a contribution percentage of 24.83%. the optimization analysis of selected variables reveals that the optimal working conditions for electrosorption of cr(vi) ions on mno2/carbon fiber electrode were at ph=2, cell voltage= 4.6v, and nacl concentration= 1.5 g/l, which was determined using the bdd. nomenclature symbols description units ac adsorption capacity mg/g ce equilibrium concentration mg/l co initial concentration mg/l m total mass of the electrode g qe adsorption capacity mg/g r2 determination coefficient re removal efficiency % x1 real ph value x2 real nacl concentration value g/l x3 real applied voltage value v xi input variables of the process xj input variables of the process xk input variables of the process z. m. issa et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 51 63 60 y response (removal efficiency) % greek letters description units 𝛽 phase of mno2 𝛽𝑜 intercept term 𝛽𝑖 linear term 𝛽𝑖𝑖 quadratic term 𝛽𝑖𝑗 interaction term 𝛾 phase of mno2 𝜃 angle radian 𝜆 wavelength a° v volume of aqueous solution m3 abbreviation symbol description adj.ms adjusted mean of square adj.ss adjusted sum of square afm atomic force microscopy anova analysis of variance bbd box–behnken design cdi capacitive deionization cf carbon fiber dc direct current dof degree of freedom edl electrical double layer edx energy-dispersive x-ray spectrometry fesem field emission scanning electronic microscopy ms mean of square rsm response surface methodology ss sum of square uv ultraviolet–visible xrd x-ray diffraction references [1] m. s. gaikwad and c. balomajumder, “current progress of capacitive deionization for removal of pollutant ions,” electrochem. energy technol., vol. 2, no. 1, pp. 17–23, 2016, https://doi.org/10.1515/eetech-2016-0004. [2] l. chen, c. wang, s. liu, and l. zhu, “investigation of adsorption/desorption behavior of cr(vi) at the presence of inorganic and organic substance in membrane capacitive deionization (mcdi),” j. environ. sci., pp. 1–12, 2019, https://doi.org/10.1016/j.jes.2018.11.005. [3] r. chen, t. sheehan, j. l. ng, m. brucks, and x. su, “capacitive deionization and electrosorption for heavy metal removal,” environ. sci. water res. technol., vol. 6, no. 2, pp. 258–282, 2020, https://doi.org/10.1039/c9ew00945k. [4] h. peng, y. leng, and j. guo, “electrochemical removal of chromium (vi) from wastewater,” appl. sci., vol. 9, no. 6, 2019, https://doi.org/10.3390/app9061156. [5] c. e. barrera-díaz, v. lugo-lugo, and b. bilyeu, “a review of chemical, electrochemical and biological methods for aqueous cr(vi) reduction,” j. hazard. mater., vol. 223–224, pp. 1–12, 2012, https://doi.org/10.1016/j.jhazmat.2012.04.054. [6] h. barabadi, s. honary, p. ebrahimi, a. alizadeh, f. naghibi, and m. saravanan, “optimization of mycosynthesized silver nanoparticles by response surface methodology employing box-behnken design,” inorg. nano-metal chem., vol. 49, no. 2, pp. 33–43, 2019, https://doi.org/10.1080/24701556.2019.1583251. [7] x. su, a. kushima, c. halliday, j. zhou, j. li, and t. a. hatton, “electrochemically-mediated selective capture of heavy metal chromium and arsenic oxyanions from water,” nat. commun., vol. 9, no. 1, 2018, https://doi.org/10.1038/s41467-018-07159-0. [8] d. e. kimbrough, y. cohen, a. m. winer, l. creelman, and c. mabuni, “a critical assessment of chromium in the environment,” crit. rev. environ. sci. technol., vol. 29, no. 1, pp. 1–46, 1999, https://doi.org/10.1080/10643389991259164. [9] p. k. ghosh, “hexavalent chromium [cr(vi)] removal by acid modified waste activated carbons,” j. hazard. mater., vol. 171, no. 1–3, pp. 116–122, 2009, https://doi.org/10.1016/j.jhazmat.2009.05.121. [10] l. khezami and r. capart, “removal of chromium (vi) from aqueous solution by activated carbons: kinetic and equilibrium studies,” j. hazard. mater., vol. 123, no. 1–3, pp. 223–231, 2005, https://doi.org/10.1016/j.jhazmat.2005.04.012. [11] a. baral and r. d. engelken, “chromium-based regulations and greening in metal finishing industries in the usa,” environ. sci. policy, vol. 5, no. 2, pp. 121–133, 2002, https://doi.org/10.1016/s14629011(02)00028-x. [12] m. s. gaikwad and c. balomajumder, “simultaneous electrosorptive removal of chromium(vi) and fluoride ions by capacitive deionization (cdi): multicomponent isotherm modeling and kinetic study,” sep. purif. technol., 2017, https://doi.org/10.1016/j.seppur.2017.06.017. [13] a. thamilselvan, a. s. nesaraj, and m. noel, “review on carbon-based electrode materials for application in capacitive deionization process,” int. j. environ. sci. technol., vol. 13, no. 12, pp. 2961– 2976, 2016, https://doi.org/10.1007/s13762-0161061-9. [14] r. rajumon, s. p. aravind, s. bhuvaneshwari, j. ranjitha, and p. mohanraj, “removal of cadmium heavy metal ions from wastewater by electrosorption using modified activated carbon felt electrodes,” water sci. technol., vol. 82, no. 7, pp. 1430–1444, 2020, https://doi.org/10.2166/wst.2020.425. [15] y. zhang et al., “progress of electrochemical capacitor electrode materials: a review,” int. j. hydrogen energy, vol. 34, no. 11, pp. 4889–4899, 2009, https://doi.org/10.1016/j.ijhydene.2009.04.005. https://doi.org/10.1515/eetech-2016-0004 https://doi.org/10.1016/j.jes.2018.11.005 https://doi.org/10.1039/c9ew00945k https://doi.org/10.3390/app9061156 https://doi.org/10.1016/j.jhazmat.2012.04.054 https://doi.org/10.1080/24701556.2019.1583251 https://doi.org/10.1080/10643389991259164 https://doi.org/10.1016/j.jhazmat.2009.05.121 https://doi.org/10.1016/j.jhazmat.2005.04.012 https://doi.org/10.1016/s1462-9011(02)00028-x https://doi.org/10.1016/s1462-9011(02)00028-x https://doi.org/10.1016/j.seppur.2017.06.017 https://doi.org/10.2166/wst.2020.425 https://doi.org/10.1016/j.ijhydene.2009.04.005 z. m. issa et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 51 63 61 [16] c. h. hou and c. y. huang, “a comparative study of electrosorption selectivity of ions by activated carbon electrodes in capacitive deionization,” desalination, vol. 314, pp. 124–129, 2013, https://doi.org/10.1016/j.desal.2012.12.029. [17] j. t. hasan and r. h. salman, “electrosorption of cadmium ions from the aqueous solution by a mno2/carbon fiber composite electrode,” desalin. water treat., vol. 243, pp. 187–199, 2021, http://doi.org/10.5004/dwt.2021.27885. [18] l. huang, s. zhou, f. jin, j. huang, and n. bao, “characterization and mechanism analysis of activated carbon fiber felt-stabilized nanoscale zerovalent iron for the removal of cr(vi) from aqueous solution,” colloids surfaces a physicochem. eng. asp., vol. 447, pp. 59–66, 2014, https://doi.org/10.1016/j.colsurfa.2014.01.037. [19] x. zhao, b. jia, q. sun, g. jiao, l. liu, and d. she, “removal of cr6þ ions from water by electrosorption on modified activated carbon fibre felt,” r. soc. open sci., vol. 5, no. 9, 2018, https://doi.org/10.1098/rsos.180472. [20] c. h. hou, c. liang, s. yiacoumi, s. dai, and c. tsouris, “electrosorption capacitance of nanostructured carbon-based materials,” j. colloid interface sci., vol. 302, no. 1, pp. 54–61, 2006, https://doi.org/10.1016/j.jcis.2006.06.009. [21] y. h. liu, h. c. hsi, k. c. li, and c. h. hou, “electrodeposited manganese dioxide/activated carbon composite as a high-performance electrode material for capacitive deionization,” acs sustain. chem. eng., vol. 4, no. 9, pp. 4762–4770, 2016, https://doi.org/10.1021/acssuschemeng.6b00974. [22] v. augustyn, p. simon, b. dunn, v. augustyn, p. simon, and b. dunn, “pseudocapacitive oxide materials for high-rate electrochemical energy storage,” energy environ. sci., vol. 7, pp. 1597– 1614, 2014, https://doi.org/10.1039/c3ee44164d. [23] m. liu, l. gan, w. xiong, z. xu, d. zhu, and l. chen, “development of mno2/porous carbon microspheres with a partially graphitic structure for high performance supercapacitor electrodes,” j. mater. chem. a, vol. 2, no. 8, pp. 2555–2562, 2014, http://doi.org/10.1039/c3ta14445c. [24] b. babakhani and d. g. ivey, “anodic deposition of manganese oxide electrodes with rod-like structures for application as electrochemical capacitors,” j. power sources, vol. 195, no. 7, pp. 2110–2117, 2010, https://doi.org/10.1016/j.jpowsour.2009.10.045. [25] z. ye, t. li, g. ma, x. peng, and j. zhao, “morphology controlled mno2 electrodeposited on carbon fiber paper for high-performance supercapacitors,” j. power sources, vol. 351, pp. 51– 57, 2017, https://doi.org/10.1016/j.jpowsour.2017.03.104. [26] y. h. liu, t. c. yu, y. w. chen, and c. h. hou, “incorporating manganese dioxide in carbon nanotube-chitosan as a pseudocapacitive composite electrode for high-performance desalination,” acs sustain. chem. eng., vol. 6, no. 3, pp. 3196–3205, 2018, https://doi.org/10.1021/acssuschemeng.7b03313. [27] c. hu, f. liu, h. lan, h. liu, and j. qu, “preparation of a manganese dioxide/carbon fiber electrode for electrosorptive removal of copper ions from water,” j. colloid interface sci., vol. 446, pp. 380–386, 2015, https://doi.org/10.1016/j.jcis.2014.12.051. [28] k. selvi, s. pattabhi, and k. kadirvelu, “removal of cr(vi) from aqueous solution by adsorption onto activated carbon,” bioresour. technol., vol. 80, no. 1, pp. 87–89, 2001, https://doi.org/10.1016/s09608524(01)00068-2. [29] p. lakshmipathiraj, g. bhaskar raju, m. raviatul basariya, s. parvathy, and s. prabhakar, “removal of cr (vi) by electrochemical reduction,” sep. purif. technol., vol. 60, no. 1, pp. 96–102, 2008, d https://doi.org/10.1016/j.seppur.2007.07.053. [30] a. ahmadi, s. heidarzadeh, a. r. mokhtari, e. darezereshki, and h. a. harouni, optimization of heavy metal removal from aqueous solutions by maghemite (γ-fe2o3) nanoparticles using response surface methodology. elsevier b.v., 2014, https://doi.org/10.1016/j.gexplo.2014.10.005. [31] kunwar p., a. k. singh, u. v. singh, and p. verma, “optimizing removal of ibuprofen from water by magnetic nanocomposite using box-behnken design,” environ. sci. pollut. res., vol. 19, no. 3, pp. 724–738, 2012, https://doi.org/10.1007/s11356-0110611-4. [32] s. polat and p. sayan, “application of response surface methodology with a box–behnken design for struvite precipitation,” adv. powder technol., vol. 30, no. 10, pp. 2396–2407, 2019, https://doi.org/10.1016/j.apt.2019.07.022. [33] j. yan, t. wei, j. cheng, z. fan, and m. zhang, “preparation and electrochemical properties of lamellar mno2 for supercapacitors,” mater. res. bull., vol. 45, no. 2, pp. 210–215, 2010, https://doi.org/10.1016/j.materresbull.2009.09.016. [34] m. ghaemi, l. khosravi-fard, and j. neshati, “improved performance of rechargeable alkaline batteries via surfactant-mediated electrosynthesis of mno2,” j. power sources, vol. 141, no. 2, pp. 340– 350, 2005, https://doi.org/10.1016/j.jpowsour.2004.10.004. [35] a. xie et al., “a coralliform-structured γmno2/polyaniline nanocomposite for highperformance supercapacitors,” j. electroanal. chem., vol. 789, pp. 29–37, 2017, https://doi.org/10.1016/j.jelechem.2017.02.032. https://doi.org/10.1016/j.desal.2012.12.029 https://doi.org/10.1016/j.colsurfa.2014.01.037 https://doi.org/10.1098/rsos.180472 https://doi.org/10.1016/j.jcis.2006.06.009 https://doi.org/10.1021/acssuschemeng.6b00974 https://doi.org/10.1039/c3ee44164d https://doi.org/10.1016/j.jpowsour.2009.10.045 https://doi.org/10.1016/j.jpowsour.2017.03.104 https://doi.org/10.1021/acssuschemeng.7b03313 https://doi.org/10.1016/j.jcis.2014.12.051 https://doi.org/10.1016/s0960-8524(01)00068-2 https://doi.org/10.1016/s0960-8524(01)00068-2 https://doi.org/10.1016/j.seppur.2007.07.053 https://doi.org/10.1016/j.gexplo.2014.10.005 https://doi.org/10.1016/j.apt.2019.07.022 https://doi.org/10.1016/j.materresbull.2009.09.016 https://doi.org/10.1016/j.jpowsour.2004.10.004 https://doi.org/10.1016/j.jelechem.2017.02.032 z. m. issa et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 51 63 62 [36] r. liu and s. b. lee, “mno2/poly (3, 4ethylenedioxythiophene) coaxial nanowires by onestep coelectrodeposition for electrochemical energy storage,” j. am. chem. soc., vol. 130, no. 10, pp. 2942–2943, 2008, https://doi.org/10.1021/ja7112382. [37] z. m. issa and r. h. salman, “chromium ions removal by capacitive deionization process : optimization of the operating parameters with response surface methodology,” j. egological eng., vol. 24, no. 1, pp. 51–65, 2023, https://doi.org/10.12911/22998993/155953. [38] w. menke, “review of the generalized least squares method,” surv. geophys., vol. 36, no. 1, pp. 1–25, 2015, https://doi.org/10.1007/s10712-0149303-1. [39] h. singh, s. sonal, and b. k. mishra, “hexavalent chromium removal by monopolar electrodes based electrocoagulation system: optimization through box–behnken design,” j. water supply res. technol., vol. 67, no. 2, pp. 147–161, 2018, https://doi.org/10.2166/aqua.2017.135. [40] u. k. garg, m. p. kaur, d. sud, and v. k. garg, “removal of hexavalent chromium from aqueous solution by adsorption on treated sugarcane bagasse using response surface methodological approach,” desalination, vol. 249, no. 2, pp. 475–479, 2009, https://doi.org/10.1016/j.desal.2008.10.025. [41] b. ayoubi-feiz, s. aber, a. khataee, and e. alipour, “electrosorption and photocatalytic one-stage combined process using a new type of nanosized tio2/activated charcoal plate electrode,” environ. sci. pollut. res., vol. 21, pp. 8555–8564, 2014, https://doi.org/10.1007/s11356-014-2777-z. [42] p. mohanraj, j. s. s. allwin ebinesar, j. amala, and s. bhuvaneshwari, “biocomposite based electrode for effective removal of cr (vi) heavy metal via capacitive deionization,” chem. eng. commun., vol. 207, no. 6, pp. 775–789, 2020, https://doi.org/10.1080/00986445.2019.16273 38. [43] p. rana-madaria, m. nagarajan, c. rajagopal, and b. s. garg, “removal of chromium from aqueous solutions by treatment with carbon aerogel electrodes using response surface methodology,” ind. eng. chem. res., vol. 44, no. 17, pp. 6549–6559, 2005, https://doi.org/10.1021/ie050321p. [44] l. huang et al., “study on mechanism and influential factors of the adsorption properties and regeneration of activated carbon fiber felt (acff) for cr(vi) under electrochemical environment,” j. taiwan inst. chem. eng., vol. 45, no. 6, pp. 2986–2994, 2014, https://doi.org/10.1016/j.jtice.2014.08.013. [45] y. chen et al., “removal of trace cd(ii) from water with the manganese oxides/acf composite electrode,” clean technol. environ. policy, vol. 17, no. 1, pp. 49–57, 2015, https://doi.org/10.1007/s10098-014-0756-1. [46] y. x. liu, d. x. yuan, j. m. yan, q. l. li, and t. ouyang, “electrochemical removal of chromium from aqueous solutions using electrodes of stainless steel nets coated with single wall carbon nanotubes,” j. hazard. mater., vol. 186, no. 1, pp. 473–480, 2011, https://doi.org/10.1016/j.jhazmat.2010.11.025. [47] p. p. mashile, m. k. dimpe, and p. n. nomngongo, “application of waste tyre-based powdered activated carbon for the adsorptive removal of cylindrospermopsin toxins from environmental matrices : optimization using response surface methodology and,” j. environ. sci. heal. part a, pp. 1–7, 2019, https://doi.org/10.1080/10934529.2019.1579538. [48] a. islam, z. nikoloutsou, and v. sakkas, “statistical optimisation by combination of response surface methodology and desirability function for removal of azo dye from aqueous solution,” int. j. environ. anal. chem., vol. 90, no. 3–6, pp. 497–509, 2010, https://doi.org/10.1080/03067310903094503. [49] n. m. k. chockalingam and r. p. k. kalaiselvan, “optimization of cnc-wedm parameters for aa2024 / zrb2 in situ stir cast composites using response surface methodology,” arab. j. sci. eng., 2020, https://doi.org/10.1007/s13369-020-04490-x. https://doi.org/10.1021/ja7112382 https://doi.org/10.12911/22998993/155953 https://doi.org/10.2166/aqua.2017.135 https://doi.org/10.1016/j.desal.2008.10.025 https://doi.org/10.1080/00986445.2019.1627338 https://doi.org/10.1080/00986445.2019.1627338 https://doi.org/10.1021/ie050321p https://doi.org/10.1016/j.jtice.2014.08.013 https://doi.org/10.1016/j.jhazmat.2010.11.025 https://doi.org/10.1080/10934529.2019.1579538 https://doi.org/10.1080/03067310903094503 z. m. issa et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 51 63 63 2mno نالكهربائي أليونات الكروم السداسية التكافؤ بواسطة القطب المركب م زازاالمت box-behnkenمن خالل تصميم وتحسينها ألياف الكربون: تحليل العملية / 2، وبراشانت باسافاراج 1 ، رشا حبيب سلمان* ،1زينب محمد عيسى قسم الهندسة الكيمياوية، كلية الهندسة، جامعة بغداد، العراق 1 جامعة بالكوت، الهند 2 الخالصة ( ، حيث تم ترسيب ثاني 2mnoتناولت هذة الدراسة طريقة تحضير قطب نانوي مركب ) ألياف الكربون / ب ( باستخدام طريقة بسيطة تدعى الترسيcfأكسيد المنغنيز ذو البنية النانوية على سطح ألياف الكربون ) ( fesemالمركبة الناتجة بأستخدام الفحص المجهري اإللكتروني ) الكهربائي األنودي. تم تشخيص األقطاب يب ( لدراسة التركxrdلدراسة شكل المادة النانوية المتكونة على سطح القطب وفحص حيود األشعة السينية ) طب البلوري للمادة المتكونة على السطح. هنالك عدد قليل جًدا من الدراسات التي قامت بدراسة كفاءة الق ، وخاصة الكروم. تم فحص خصائص االمتزاز الكهربائي في إزالة المعادن الثقيلة cf 2mno /ر المحض من محلول مائي. لدراسة تأثير العوامل cr (vi)عن طريق إزالة أيونات cf 2mno /للقطب النانوي لوريدكموضة وتركيز التشغيلية المختلفة والتفاعل فيما بينها على كفاءة عملية االزالة، تم اختيار درجة الح هرت النتائج أنه عند (، أظbdd) box-behnkenالصوديوم وجهد الخلية كظروف تشغيلية. باستخدام تصميم جم / لتر تم تحقيق 1.5فولط وتركيز كلوريد الصوديوم = 4.6، جهد الخلية = 2الرقم الهيدروجيني = cr (vi)تم تحقيق كفاءة عالية في ازالة أيونات . في هذه الدراسةcr (vi)الظروف المثلى إلزالة أيونات كانت استراتيجية مجدية وفعالة لتقييم البيانات bbdوأن طريقة 2mnoبأستخدام قطب ألياف الكربون / التجريبية في ظروف مختلفة. نانوي تركيب ال، الالترسيب الكهربائيمركب، ، القطب الالكهربائي، أيونات الكروم سداسية التكافؤ عملية االمتزاز الكلمات الدالة: 2mno تصميم ،behnken-box. iraqi journal of chemical and petroleum engineering vol.17 no.1 (march 2016) 6170 issn: 1997-4884 synergistic effect of potassium iodide on inhibitive performance of propyl alcohol during corrosion of mild steel in 1.0m hcl aprael. s.yaro, basma a. abdul majeed, and elaf q. atiyah chemical engineering department-college of engineering-university of baghdad-iraq abstract the inhibition of mild steel corrosion in 1.0m hcl by 1-propanol and the synergistic effect of potassium iodide (ki) was investigated using weight loss and polarization techniques in he e e e ge 3 5 matrix of doelhert to three factors was used as the experimental design, adopting weight loss results as it permits the use of the response surface methodology which exploited in determination of the synergistic effect as inhibition on the mild steel. the results were confirmed using electrochemical polarization measurements. experimental results showed that the inhibition efficiency (ie%) increases with increase in concentration of inhibitor and with increasing of temperature. the addition iodide ions to alcohol (inhibitor) enhanced the inhibition efficiency due to synergistic effect. potentiodynamic polarization studies showed that the studied compound is mixed-type inhibitor causing blocking of active sites on the mild steel surface .the adsorption of the inhibitor and its combination with iodide ions on mild steel surface followed langmuir adsorption isotherm via physisorption mechanism, which was proposed based on values of adsorption gibbs free energy difference δgads. statistically, the multi-variable regression equation describes the behavior of the corrosion inhibition process with high accuracy (correlation coefficient r 2 between 0.974 and 1). key words: acid corrosion, synergistic effect, mild steel, potentiodynamic polarization, weight loss method, doelhert design introduction despite mild steel has a relatively high cost; it is widely used in collective amounts in chemical processing, petroleum production and efi i g, co s c io d etal processing equipment, and marine applications. these applications usually stimulate corrosion attack on metallic equipment, pipelines and tubes made of iron and its alloys, especially in acidic environments [1]. the study of corrosion inhibition of mild steel in acid solutions have practical importance because that acid solutions are widely used in many industrial processes such as acid pickling of metals , acid cleaning of boilers, scale removal in metallurgy and oil well acidizing. to minimize the metal loss during this process different corrosion inhibitors are used in corrosive solutions. some organic compounds are found to be effective corrosion inhibitors for many metals iraqi journal of chemical and petroleum engineering university of baghdad college of engineering synergistic effect of potassium iodide on inhibitive performance of propyl alcohol during corrosion of mild steel in 1.0m hcl 62 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net and alloys in acidic media. these act as corrosion inhibitors according to their functional groups (effective groups), which are adsorbed on the metal surface. the adsorption of these organic molecules depends mainly on some physic-chemical properties of the inhibitor such as the functional group, steric factor, aromaticity, electron density at the donor atoms and porbital character of donating electrons [2 4], and the electronic structure of the molecules [5]. the adsorption ability of organic cations is increased by the addition of halide ions to the corrosive media. interconnecting bridges between the negatively charged metal surface and the cations of inhibitor are formed. synergism is an effective approach to enhance the inhibition efficiency of the inhibitors to decrease the dosage of organic compounds and to diversify the application of the inhibitors in acidic media [6]. the order of synergism of halide ions is i ˃ br ˃cl [7] because it has larger size and easy polarizability, i ions are chemisorbed on the metal surface and provide better synergistic effect [8]. experimental method a mild steel sheet was used as working electrode of 2cm (width), 3cm (length), and 0.1cm (thickness) in weight loss method. area bout (4.97cm²) was used for polarization method. the following composition (wt %) si – 0.01, al – 0.004, cu – 0.055, mn – 0.346, mo – 0.002, cr – 0.035, ni – 0.056, co – 0.007, p – 2, s 21, 67, d he balance fe. the aggressive medium (1.0m hcl) was prepared by dilution of analytical grade 37% hcl, and appropriate concentrations of inhibitor were obtained using distilled water. weight loss method the specimens were smoothened by emery papers and then cleaned with tap water, distilled water, benzene and acetone. after that they were dried and weighed on a digital scale. each of the specimens is designated and its initial weight is noted. after each test, the specimen was washed with running tap water, scrubbed with a brush to remove corrosion products, then washed with tap water followed by distilled water and dried on clean tissue, immersed in benzene, dried, immersed in acetone, dried and left in a desiccators over silica gel until use. the time of immersion in hcl solutions was four hours. polarization technique the electrochemical cell was composed of graphite counter electrode, prepared mild steel specimen as working electrode and saturated calomel electrode (sce) as a reference electrode. the corrosion potential (ecorr) was measured against sce. the corrosion cell parts were joined to each other, and then connected to potentiostat (tacussel type prt 10-05, france), ammeter and voltmeter. starting with cathodic polarization until it reaches the corrosion potentials, then continuing with anodic polarization. the potential was changed (20-25mv) for each step after one minute period the current was recorded. results and discussion 1weight loss method corrosion inhibition (ie%) efficiency calculations from weight loss data were performed according to equation: ie (%) = *100 … 1 aprael. s.yaro, basma a. abdul majeed, and elaf q. atiyah -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 63 where wo and w are the weight loss of mild steel in the absence and presence of inhibitor, respectively. table (3) display the applied doehlert matrix design [9]. the i i hi i io efficie c fo 1 o o s o i ed i h ese ce 367m of coho , d 4m ki, 5 i is 94 s sho i e (2). it is clear that the addition of ki enhanced the inhibition efficiency and this indicates a synergistic effect between 1-propanol with ki. the formula used for calculation of the number (n) of experiments required is (n=n 2 +n+ no), where (n) is the number of variables and (no) is the number of center points[10]. a quadratic polynomial model is established to evaluate the effect of the three factors on the response: y = b0 + b1x1 + b2x2 + b3x3 + b4x1x2 + b5x1x3+ b6x2x3 + b7x1 2 + b8x2 2 + b9x3 2 … 2 where: y: inhibition efficiency; x1, x2 and x3: independent variables representing the concentration of ki, the concentration of alcohol and temperature of the solution, respectively; b0: constant; b1, b2 and b3: coefficients reflecting the effect of factors x1, x2, and x3; b4, b5, and b6:coefficients reflecting the interaction between two factors x1x2, x1x3and x2x3 ; b7, b8 and b9: coefficients reflecting the influence of quadratic x1,x2, and x3[11]. table(1) represents the low and high levels factor, the matrix of the doelhert design and results are shown in table (2) . table 1, factors and levels used in doelhert experimental design. variable low level high level ki conc.(m) x1 0.03 (-1) 0.07(+1) propanol conc.(m) x2 0.1 (-1) 0.5(+1) temp.( 0 c) x3 30 (-1) 50(+1) the centers and the variation steps for the three studied factors are shown in table (3) according to doelhert experimental design. table (2) center and variation step of parameters. factor unit center variatio n step x1 temp. ◦ c 40 10 x2 alcohol conc. m 0.3 0.2 x3 ki con. m 0.05 0.02 the results were analysed using the analysis of variance as appropriate to experimental design used. the regression equations obtained for 1propanol after analysis of variance gives the levels of corrosion inhibition of mild steel as function of the three variables: temperature (x1), alcohol concentration (x2), and ki concentration (x3). all terms were included in the following equations: y1= 0.034 + 4.28x1 + 0.239x2 + 248x3 1 25x1x2 – 0.117x1x3 – 0.0137x2x3 +9.1x1 2 +0.551x2 2 0.000075x3 2 … (3) where: y1 is the response, that is corrosion inhibition of mild steel, and x1, x2, and x3 are the real values of the test variables, temperature (x1), alcohol concentration (x2), and ki concentration (x3), respectively. synergistic effect of potassium iodide on inhibitive performance of propyl alcohol during corrosion of mild steel in 1.0m hcl 64 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net 2polarization technique tafel extrapolation method can be applied in order to obtain representative values of the corrosion rate in 1.0mhcl solution. the polarization profiles of mild steel in 1.0m hcl solution at 30, 40, and 50°c for various alcohol concentrations in the absence and presence of ki are shown in figures (1) through (3). the presence of increasing amounts of of 1-propanol led to a decrease in both the cathodic and anodic current densities. the addition of alcohol reduced anodic dissolution and also retarded the hydrogen evolution reaction, indicating that alcohol is a mixed-type inhibitor and controls both the anodic and cathodic reactions. the decrease in (icorr) value was due to the adsorption of the inhibitor molecules [12].the values of electrochemical parameters such as corrosion potential (ecorr), corrosion current density (icorr), anodic and cathodic slopes ( and corresponding efficiencies were calculated from tafel plots (table(4)).from the polarization curves it was noted that the curves were shifted toward lower current density region without significant change in corrosion potential. the maximum shift obtained (28mv) was another reason proved that the investigated compound behaved as mixed-type of inhibitor. βc values increased with the increase in concentration of inhibitor compound and the presence of ki[1316]. table 3, experimental design based on doehlert matrix in the study of the corrosion inhibition of carbon steel using 1-propanol alcohol and ki synergistic effect, in 1m hcl. exp. no. coded variable real variable inhibition efficiency (ie%) xi ki conc. x2 alcohol conc. x3 temp. xi ki conc. x2 alcohol conc. x3 temp. 1 +1 0.0 0.0 0.07 0.3 40 85.08 2 -1 0.0 0.0 0.03 0.3 40 84.03 3 +0.5 +0.866 0.0 0.06 0.5 40 84.69 4 -0.5 -0.866 0.0 0.04 0.1 40 89.20 5 +0.5 -0.866 0.0 0.06 0.1 40 89.70 6 -0.5 +0.866 0.0 0.04 0.5 40 85.67 7 +0.5 +0.289 +0.816 0.06 0.367 50 92.49 8 -0.5 -0.289 -0.816 0.04 0.233 30 72.26 9 +0.5 -0.289 -0.816 0.06 0.233 30 73.66 10 0.0 +0.577 -0.816 0.05 0.433 30 80.65 11 -0.5 +0.289 +0.816 0.04 0.367 50 94.10 12 0.0 -0.577 +0.816 0.05 0.167 50 93.05 13 0.0 0.0 0.0 0.05 0.3 40 85.18 14 0.0 0.0 0.0 0.05 0.3 40 84.15 15 0.0 0.0 0.0 0.05 0.3 40 89.48 aprael. s.yaro, basma a. abdul majeed, and elaf q. atiyah -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 65 table 4, corrosion parameters for mild steel in 1m hcl at different temperatures, different concentrations of 1-propanol, with and without 0.05m ki inhibitor conc.(m) temp. ecorr (mv) icorr (ma/cm 2 ) βc (mv/dec) βa (mv/dec) ie% 1m hcl 30 -502 0.239 -75.12 64.83 0.1 -508 0.146 -84.17 58.33 38.91 0.1+0.05m ki -506 0.0706 -108.6 46.52 70.46 0.3 -515 0.099 -94.75 42.33 58.58 0.3+0.05m ki -497 0.055 -113.9 42.02 76.98 0.5 -500 0.079 -89.46 31.46 66.94 0.5+0.05m ki -474 0.0444 -183.4 93.61 81.42 1m hcl 40 -492 0.373 -83.43 48.78 0.1 -503 0.244 -85.64 49.68 34.58 0.1+0.05m ki -491 0.051 -85.16 50.53 86.33 0.3 -502 0.159 -109.8 54.67 57.37 0.3+0.05m ki -500 0.0659 -94.93 60.24 82.33 0.5 -498 0.126 -90.6 42.49 66.21 0.5+0.05m ki -489 0.0676 -75.87 40.19 81.87 1m hcl 50 -494 0.716 -72.98 48.67 0.1 -500 0.484 -80.38 34.79 32.40 0.1+0.05m ki -490 0.0396 -85.2 46.38 94.47 0.3 -486 0.367 -83.76 35.43 48.47 0.3+0.05m ki -503 0.0467 -97.33 55.42 93.47 0.5 -495 0.255 -79.7 29.06 64.39 0.5+0.05m ki -489 0.0426 -75.87 40.19 94.05 fig. 1, tafel polarization curves for corrosion of mild steel in 1m hcl at 30°c in the presence of different concentrations of 1-propanol (p) with and without 0.05m ki. fig. 2, tafel polarization curves for corrosion of mild steel in 1m hcl at 40°c in the presence of different concentrations of 1-propanol (p) with and without 0.05m ki. synergistic effect of potassium iodide on inhibitive performance of propyl alcohol during corrosion of mild steel in 1.0m hcl 66 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net fig. 3, tafel polarization curves for corrosion of mild steel in 1m hcl at 50°c in the presence of different concentrations of 1-propanol (p) with and without 0.05m ki. 3corrosion kinetic parameters the temperature effect o he co osio e e s of i d s ee i 1 m h s s died 3 , 4 , d 5 the i hi i io ech is c e concluded by comparing the activation energy values in the presence and absence of the inhibitor. the plots of arrhenius or transition state were used to calculate the activation energy (ea), activation enthalpy (δha), and activation entropy (δsa) for the corrosion of mild steel in 1.0 m hcl with and without inhibitor. the activation energy can be obtained by arrhenius equation and arrhenius plot [17]: icorr v= … (4) where: icorr is the corrosion current density (taken from polarization measurements) in ma/cm 2 , a is the electrochemical constant(arrhenius constant), ea is the activation energy in j/ mol, r is the gas constant (8.314 j/ mol. k) and t is temperature in k. using the logarithm: lnicorr = ( )( )+lna … (5) the graph of lnicorr against 1000/t gives a straight line with a slope of (‒ea/r). figure (4) shows the arrhenius plots for mild steel in 1.0 m hcl with different concentration of 1propanol with and without 0.05m ki.(ea) values were calculated and tabulated in tables (5). the transition state equation was used to calculate the δha and δsa: icorr = exp( exp( … 6 whe e: n is vog d o’s e (6.02×10 23 mol -1 d h is p ck’s constant (6.63 × 10 -34 m 2 kg s -1 )[17]. the activation energy is a temperature dependent quantity as follows: ea = δha ‒ tδsa … 7 equation (5) was rearranged to become: ln( )=( +[ln( + ]... (8) a plot of ln (icorr/t) against 1000/t gave a straight line with a slope of (δha/r) and intercept of [ln (r/nh)+(δsa/r)] as shown in figures (4) and (5). δha and δsa values were calculated and tabulated in table (5). from table (5) the activation energy (ea) increased in the presence of the inhibitor. (ea) increasing with the presence of1-propanol indicated a physical (electrostatic) adsorption occurred in the first stage. both the inhibitors are organic compounds that are easily protonated to give a cationic form in acid medium. the values of (ea) were greater than 20 kj mol 1 in the presence of alcohol, which aprael. s.yaro, basma a. abdul majeed, and elaf q. atiyah -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 67 indicates that the entire process is controlled by the surface reaction [18]. the values of δha and ea were nearly the same and higher in the presence of alcohol. this indicates that the energy barrier of the corrosion reaction increased in the presence of the inhibitor without changing the mechanism of dissolution. the positive values of δha for both corrosion processes with and without the inhibitor show the endothermic nature of the mild steel dissolution process and indicate that the dissolution of mild steel is difficult [19,20]. the increase in δsa values in the presence of inhibitor with and without ki indicated that the process of adsorption was spontaneous [16]. fig.4, arrhenius plots for mild steel in 1.0 m hcl with different concentrations of 1-propanol at different temperatures. fig. 5, transition state plots for mild steel in 1.0 m hcl with different concentration of 1-propanol at different temperatures. table 5, corrosion kinetic parameters for mild steel in 1.0 m hcl and different concentration of 1-propanol in the presence and absence of 0.05m ki inhibitor conc.(m) ea (kj/mol) δha (kj/mol) δsa (kj/mol.k) 1m hcl 44.54 41.93 -118.87 0.1 48.66 46.07 -109.33 0.3 53.13 50.52 -98.11 0.5 47.55 44.95 -118.15 0.1+0.05m ki 23.55 -26.14 -353.43 0.3+0.05m ki 6.418 -9.02 -215.08 0.5+0.05m ki 19.29 -21.9 -338.96 4adsorption isotherm adsorption isotherm calculations of 1-propanol on the mild steel surface were performed to investigate the mechanism of corrosion inhibition in the presence and absence of 0.05m ki. f c io cove ge v es θ e e obtained from polarization measurements to yield the isotherm. totally, isotherms adsorption provides data about the interaction among the adsorbed molecules themselves and their interactions with the electrode surface [21]. the fraction coverage θ is calculated using the following equation: … 9 where: and are the corrosion current densities in the absence and presence of the additive compounds. in order to study the different types of adsorption isotherm models, the temkin, frumkin and langmuir models have been plotted. synergistic effect of potassium iodide on inhibitive performance of propyl alcohol during corrosion of mild steel in 1.0m hcl 68 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net according to the r 2 values obtained from the linear graph, it was confirmed that the adsorption of the two compounds on a mild steel surface best fitted the langmuir adsorption isotherm (which assumes that the metal surface contains a fixed number of adsorption sites and each one holds one adsorbed species) model which is represented by equation (9): … 9 where: cinh is the concentration of inhibitor and kads is the adsorption constant which is related to the standard free energy adsorption, δg°ads, as follows [22]: δg°ads = -rt ln(55.5kads) … (10) the value of 55.5 is the molar concentration of water in the solution. the plot of cinh/θ g i s i h i figures (6) through (8) yields a straight line and this supported the assumption that the adsorption of the each applied inhibitor in the presence and absence of ki on a mild steel surface in 1.0 mhcl solution obeys the langmuir adsorption isotherm. the i c e si g v e of δg°ads and kads in the presence of ki reflects the increasing adsorption capability and the negative value of δg°ads indicates spontaneous adsorption of inhibitor molecule on the metal surface[21]. it is well known that large values of kads mean better inhibition efficiency of the inhibitor, i.e., strong electrostatic interaction between the negatively charged metal surface and the positively charged entities of the adsorbing inhibitor molecules. δg°ads and kads values are tabulated in table (6): fig. 6, adsorption isotherms for mild steel in1.0 m hcl in different co ce io s of 1 o o coho 3 i the presence and absence of 0.05m ki fig. 7, adsorption isotherms for mild steel in 1.0 m hcl in different co ce io s of 1 o o coho 4 i he resence and absence of 0.05m ki fig. 8, adsorption isotherms for mild steel in 1.0 m hcl in different concentrations of 1-propanol alcohol at 5 i he resence and absence of 0.05m ki aprael. s.yaro, basma a. abdul majeed, and elaf q. atiyah -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 69 table 6, corrosion parameters for mild steel in 1.0 m hcl and 1-propanol alcohol in the presence and absence of 0.05m ki. inhibitor temp.°c kads δg° ds (kj/mol) 1-propanol 30 7.194 -15.09 40 5.618 -14.94 50 4.61 -14.89 1-propanol +ki 30 37.04 -19.22 40 166.67 -23.77 50 14285.7 -36.48 conclusions 1a 1-propanol acts as moderate inhibitor for mild steel in 1.0 mhcl. 2potentiodynamic polarization and weight loss studies showed that the 1-propanol is mixed-type inhibitors. 3the inhibition efficiency increases with increase in concentration of both inhibitor and with increasing of temperature. 4the addition of iodide ions to 1propanol (inhibitor) enhanced the inhibition efficiency due to synergistic effect. 5the adsorption of inhibitor (1propanol) alone and in combination with iodide ions obeys langmiur adsorption isotherm. 6the thermodynamic parameters calculated from the adsorption isotherm showed that physisorption is involved in the inhibition process, which was proposed based on values of δg°ads. 7statistically, the multi-variable regression equations describes the behavior of the corrosion inhibition process with high accuracy (correlation coefficient r 2 between 0.984 and 1). references 1f g, , d heg z , m ,” synergistic inhibition effect of potassium iodide and novel schiff bases on x65 steel corrosion in 0.5 m h2so4”, o sci , 74 2 13 168–177. 2elkadi, l., mernari, b., traisnel, m., bentiss, f. and lagrenée, m. “the inhibition action of 3,6-bis(2methoxyphenyl)-1,2-dihydro1,2,4,5-tetrazine on the corrosion of mi d s ee i cidic medi ”, o sci , 42 2 7 3 716 3k ed, k f , “the inhibition of benzimidazole derivatives on corrosion of iron in 1 m hcl so io s”, e ec ochi c 48 (2003) 2493–2503. 4chetouani, a., hammouti, b., benhadda, t. and daoudi, m.” inhibitive action of bipyrazolic type organic compounds towards corrosion of pure iron in acidic medi ” , appl. surf. sci., 249 (2005) 375 385. 5lebrini, m., lagrenée, m., vezin, h. gengembre, l. and bentiss, f. “e ec oche ic d q chemical studies of new thiadiazole derivatives adsorption on mild steel in normal h d och o ic cid medi ”, o sci , 47 2 5 485 5 5 6xianghong li, shuduan deng, hui fu, and guannan mu , “s e gis ic inhibition effect of rare earth cerium (iv) ion and sodium oleate on the corrosion of cold rolled s ee i phos ho ic cid so io ”, o sci , 52 2 1 1167 1178 7fuchs-godec r., miomir g., p v ovic, “s e gis ic effec between non-ionic surfactant and halide ions in the forms of inorganic or organic salts for the corrosion inhibition of stainlesss ee x4 13 i s h ic cid”, o sci 58 2 12 192 2 1 8mu, g.n., li x.m., and li f., “s e gis ic i hi i io e ee ophenanthroline and chloride ion on cold rolled steel corrosion in phos ho ic cid”, m e he ph s 86 2 4 59 68 http://www.sciencedirect.com/science/journal/00134686/48/17 http://www.sciencedirect.com/science/journal/00134686/48/17 synergistic effect of potassium iodide on inhibitive performance of propyl alcohol during corrosion of mild steel in 1.0m hcl 70 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net 9abdul majeed, b.a., and atiyah, e. q ,” synergistic effect of alcohol and potassium iodide on the kinetics and inhibition of mild steel corrosion in 1m hydrochloric acid at different temperatures “,u iv o bagh., coll.o. engine., chem. engine.dep., 2015. 10m ss ,d l e ,” h d ook of chemoe ics d q i e ics”, part a, elsevier, amsterdam, 2003. 11forsal, i., ebn touhami, m., mernari, b. el hajri, j. and filali baba, m “use of e e i e designs to evaluate the influence of 2-mercaptobenzimidazole on the corrosion of mild steel in hcl (1m) environment in the presence of coho e ho e”, portugaliaeelectrochimicaacta 2010, 28(3), 203-212. 12ahamad,, i., prasad, r. and quraishi, m , “experimental and theoretical investigations of adsorption of fexofenadine at mild steel/hydrochloric acid interface as co osio i hi i o ”, j. solid state e ec oche 14 2 1 2 95 21 5 13 ferreira,e.s, giacomelli,c, giacomelli, f.c and spinelli. a, “ev io of he i hi i o effec of l-ascorbic acid on the corrosion of mi d s ee ”, m e he ph s 83 2 4 129 134 14wei-hua li, qiao he, sheng-tao zhang, chang-ling pei, and barorong hou., “so e ne t i zo e derivatives as inhibitors for mild steel corrosion in acidic medi ”, j. appl. electrochem. 38 2 8 289 295 15herrag, l., hammouti, b., elkadiri, s. aouniti, a., jama, c.,vezin, h. and bentiss. , "adsorption properties and inhibition of mild steel corrosion in hydrochloric solution by some newly synthesized diamine derivatives: experimental and theoretical investigations", corr. sci.,52(2010) 3042-3051. 16behpour, m., ghoreishi, s. m., soltani, n., salavati-niasari, m. hamadanian, m. and gandomi. a., "electrochemical and theoretical investigation on the corrosion inhibition of mild steel by thiosalicylaldehyde derivatives in hydrochloric acid solution", corr. sci., 50(2008) 2172-2181. 17musa, a. y. et.al, “synergistic effect of potassium iodide with phthalazone on the corrosion inhibition of mild steel in 1 mh ”, o sci , 53 2 11 3672–3677. 18el ouali, i., hammouti, b., aouniti, a., ramli, y., azougagh, m., essassi, e. m., and bouachrine, m. "thermodynamic characterisation of steel corrosion in hcl in the presence of 2-phenylthieno (3,2-b) quinoxaline", j. mater. environ. sci ,1 2 1 1 8 19kumar, sh. s., and quraishi, “ceftriaxone: a novel corrosion inhibitor for mild steel in h d och o ic cid”, j appl.electrochem, 39 2 9 1517 1523 20apparao, b. v.,yakubiqbal, md., d s eedh , b ,” e ec oche ic and surface analytical studies of the self-assembled monolayer of 5methoxy-2(octadecylthio)benzimidazoleiin corrosion pro ec io of o e ”, electrochimicaacta, 55(2010) 620– 631. 21 d h, m , ʺrho d i e zos h as corrosion inhibitors for corrosion of 304 stainless steel in h d och o ic cid so io ʺ , o sci ,44 2 2 717 728 22shaju, k.s., joby thomas, k., vinod p. raphael, and aby paul,ʺ synergistic effect of ki on corrosion inhibition of mild steel by polynuclear schiff base in s h ic cidʺ, i e io scholarly research network, volume 2012, article i d 425878, 8 pages. http://www.sciencedirect.com/science/article/pii/s0254058403004516 http://www.sciencedirect.com/science/article/pii/s0254058403004516 http://www.sciencedirect.com/science/article/pii/s0254058403004516 http://www.sciencedirect.com/science/article/pii/s0254058403004516 http://www.sciencedirect.com/science/article/pii/s0254058403004516 http://link.springer.com/search?facet-creator=%22wei-hua+li%22 http://link.springer.com/search?facet-creator=%22qiao+he%22 http://link.springer.com/search?facet-creator=%22sheng-tao+zhang%22 http://link.springer.com/search?facet-creator=%22sheng-tao+zhang%22 http://link.springer.com/search?facet-creator=%22chang-ling+pei%22 http://www.sciencedirect.com/science/article/pii/s0010938x10002696 http://www.sciencedirect.com/science/article/pii/s0010938x10002696 http://www.sciencedirect.com/science/article/pii/s0010938x10002696 http://www.sciencedirect.com/science/article/pii/s0010938x10002696 http://www.sciencedirect.com/science/article/pii/s0010938x10002696 http://www.sciencedirect.com/science/article/pii/s0010938x10002696 http://www.sciencedirect.com/science/article/pii/s0010938x10002696 http://www.sciencedirect.com/science/article/pii/s0010938x08001996 http://www.sciencedirect.com/science/article/pii/s0010938x08001996 http://www.sciencedirect.com/science/article/pii/s0010938x08001996 http://www.sciencedirect.com/science/article/pii/s0010938x08001996 http://www.sciencedirect.com/science/article/pii/s0010938x08001996 http://www.sciencedirect.com/science/article/pii/s0010938x08001996 http://www.sciencedirect.com/science/article/pii/s0010938x08001996 http://www.sciencedirect.com/science/article/pii/s0010938x08001996 http://www.hindawi.com/57639724/ http://www.hindawi.com/15963493/ http://www.hindawi.com/74851284/ http://www.hindawi.com/74851284/ http://www.hindawi.com/83942893/ available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.23 no.3 (september 2022) 35 – 41 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: fadhil hameed alshibli , email: fadhil.ali2008m@coeng.uobaghdad.edu.iq, name: ayad a. alhaleem a. alrazzaq, email: dr.ayad.a.h@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. laboratory testing and evaluating of shale interaction with mud for tanuma shale formation in southern iraq fadhil hameed alshibli and ayad a. alhaleem a. alrazzaq petroleum department, college of engineering, university of baghdad, baghdad, iraq abstract rock failure during drilling is an important problem to be solved in petroleum technology. one of the most causes of rock failure is shale chemical interaction with drilling fluids. this interaction is changing the shale strength as well as its pore pressure relatively near the wellbore wall. in several oilfields in southern iraq, drilling through the tanuma formation is known as the most challenging operation due to its unstable behavior. understanding the chemical reactions between shale and drilling fluid is determined by examining the features of shale and its behavior with drilling mud. chemical interactions must be mitigated by the selection of suitable drilling mud with effective chemical additives. this study is describing the laboratory methods that concern testing and evaluating the shale instability encountered while drilling operations. the cutting samples are collected from the targeted formation and used to categorize shale reactivity levels and the required additives to inhibit the clay instability. these tests include the descriptive method with the various analytical technique of standard laboratory equipment. the shale testing techniques are the scanning electron microscope (sem), x-ray diffraction, x-ray fluorescence, cation-exchange, capacity (cec), and capillary suction timer test (cst). also, linear swelling meter test (lsm) was performed to enhance the development plan. tanuma formation contains moderately active clay with the presence of microfractures and micropores in its morphology. and it is controllable by using polymer muds with 8 % of inorganic inhibitor (e.g., kcl), filtration controls additives, and poly amino acid hydration suppressant which showed minimum swelling percentage. keywords: shale rock, tanuma shale, shale failure, shale swelling, shale-mud interaction received on 06/04/2022, accepted on 25/05/2022, published on 30/09/2022 https://doi.org/10.31699/ijcpe.2022.3.5 1introduction the shale rocks represent around 75% of the drilled formations and 70% of the downhole problems encountered while drilling to the targeted pay zones. it is still early to say that the shale issue is controlled as the oil and gas industry is still making efforts to control the shale instability issues. the drilling costs are still carrying a vast involvement in the shale instability issues due to many downhole problems, such as tight holes, hole collapse, poor hole cleaning, and stuck pipe. these issues are mainly created and developed due to the nonexistence of knowledge about the drilled formation [1]. shale instability is a serious issue that appears when it is exposed to drilling muds. it might be encountered due to chemical interaction between the drilling fluid and shale rock or due to mechanical effects resulting from unbalanced stresses between the wellbore and formation being drilled. however, it is necessary to predict wellbore instability before drilling any well for reducing or eliminating the risk of downhole problems. and the result of stable drilling is leading to minimizing the overall well costs which might be major [2]. analyzing the shale instability, based only on the mechanical mechanisms, is an incorrect workflow, which is beyond the scope of this research. it is required to be analyzed aside from the mechanism of shale-drilling fluids interaction [3]. chemical interactions must be mitigated by selecting suitable drilling muds with effective chemical additives. an effort must be made to understand the chemical reactions between shale and drilling fluid by examining the features of shale when drilling mud is present. then, using effective laboratory tests, that are indicative of the shale compositions and concentrations of the chemical in the drilling fluids, will lead to a significant improvement in mitigating and reducing the risk of interaction between shale and fluids [4]. this study is evaluating the shale reactivity and rectifies the failure by using mud additives that suit the tanuma structure and properties. the cutting samples are collected from the targeted formations and used to categorize shale reactivity levels and the required additives to inhibit the clay instability. these tests include the descriptive with the various analytical technique of standard laboratory equipment. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:fadhil.ali2008m@coeng.uobaghdad.edu.iq mailto:fadhil.ali2008m@coeng.uobaghdad.edu.iq mailto:dr.ayad.a.h@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2022.3.5 f. h. alshibli and a. a. a. alrazzaq / iraqi journal of chemical and petroleum engineering 23,3 (2022) 35 41 36 the shales minerals are categorized by the x-ray diffraction (xrd) technique, the shale geochemical are analyzed by the x-ray fluorescence (xrf) method and then the scanning electron microscope (sem) was then involved to enhance the decision of the shale reactivity analysis and to help for understanding the instability mechanisms which might be encountered due to microfractures and pores. the capacity of exchanging the cations (cec test), which are present on the clay of the shale, was also performed to indicate the reactivity potential of shale samples. the xrd and the cec methods combined to anticipate the need for inhibitions in drilling fluids. additionally, the capillary suction time (cst) test was implemented on the shale to optimize the required inhibitor to stop shale dispersion into the fluid. by combining the obtained results from the analysis of the shale samples methods (sem, xrd and xrf) and the method of evaluating the direct interaction of the rock samples with the fluids (cec and cst), the shale reactivity levels are assessed for tanuma shales. based on that, a development plan was formulated and tested the shale stability with the new muds by linear swelling meter test (lsm) [5], [6]. 1.1. shale failure shale failure starts to occur when an insufficient type of mud is used to drill shale intervals where it depends on the properties of both shale rocks (e.g., mineralogy, porosity) and the drilling muds used to drill the shale (e.g., salinity, ionic exchange). it is also encountered if the effective stress in the drilled wellbore exceeds the strength of the hole. the shale is already in equilibrium (stresses and pore pressure) which is naturally established between the stress and the strength. when the native shale is exposed to a sudden alter in its environment and foreign chemicals from mud, it will disperse into mud. the reaction between drilling fluid and shale changed its strength as well as pore pressure relatively to the hole wall. shale rock strength usually decreases, and pore pressure increases when fluid penetrates shale [6]. 1.2. chemical effect chemical effect is the interaction process between shale minerals (clay) and drilling fluids when shales expose to drilling operations. it is an important phenomenon in borehole stability. the fundamental of this interaction is the driving force for the water movement into or out of the shale formation [3], [8]. chemical interactions, that occur between drilling fluids and shale rocks (clay-rich shale), are leading to affect rock strength and wellbore (local) formation pore pressure, thus, causing borehole failure. in the context of the theory described by mody and hale (1993). the three influential factors, that lead to well instability issues, when chemical effects may encounter are: the first factor is, relatively, the salinity of drilling fluid relevant to the fluid in shale pores. that is identified as the water activity (am) and it is inversely proportional to the salinity. if the mud reactivity is above the reactivity of the fluid in a formation (ap), the osmosis phenomena will occur which raises the shale pore pressure and cause the instability issue. simply, osmotic pressure means the movement of the fluid from the less saline side toward the more saline side. the osmotic pressure concept, which is greatly impacting borehole stability, is easier to be understood while using waterbased drilling fluids. second, the changes in shale pore pressures are eliminated to the membrane efficiency, which is defined by how easily ions will move from drilling fluids into the shale formation. third, the exchange capacity of ions in the shales is crucial because the changing of cations like mg++ by ca++ and na+ by k+ will weaken the shale rock [3]. 2experimental work laboratory tests are conducted to describe and evaluate the shale reactivity of the tanuma formation and to estimate the shale-mud interaction as follows: 2.1. tanuma shale description tanuma shale formation is 100% shale. the cutting samples are checked visually and by using a microscope. it was described as dark gray, olive-gray, slightly hard, fissile to sub fissile, sub blocky, splintery, occasionally tabular, and non-calcareous, as shown in fig.1. fig. 1. tanuma shale sample under the microscope 2.2. tanuma shale structure the scanning electron microscope test (sem) was carried out to investigate the tanuma shale structure and to observe the substructure morphology of the shale (micro-pores, micro-crakes, and micro-fractures). as shown in fig. 2, there is a significant presence of micropores and microfractures in tanuma shale. the length of the microfractures is ranged between 10 to 16 μm and their widths are ranged from 1 to 3 μm. the presence of micro-pores, cracks, and fractures becomes channels when the drilling fluid become in contact with shale, and these channels act to provide a path across the wellbore for the drilling mud and fluids and to inside the shale rock. the penetration of fluid will cause the shale-swelling, which leads to an increase in the pore pressure and affects the base fluid saturations. f. h. alshibli and a. a. a. alrazzaq / iraqi journal of chemical and petroleum engineering 23,3 (2022) 35 41 37 these activities and the nature of the shale structure are considered critical factors and play a vital role in shale failures and wellbore instability [9]. fig. 2. tanuma shale structure observed by scanning electron microscope test 2.3. tanuma shale mineralogy the x-ray diffraction detector (xrd) was used to analyze the shale mineralogy and the presence of deferent minerals, which are the clay and non-clay mineral in shale. tanuma cutting samples were collected from a drilling rig, cleaned, and washed on-site to remove the residual of the drilling mud. the cuttings were dried in the electrical oven less than 105 c for 2.5 hours to remove clear the shale from the water. the samples are ground and milled to a fine powder for the purpose of the accuracy of the results. the test was performed with shale powder and results are shown in fig. 3, tanuma formation mainly consists of clay minerals with non-clay minerals. it is also noticeable; that clay minerals represent a higher percentage than nonclay minerals. tanuma formation mainly consists of kaolinite, chlorite, illite, and palygorskite, as the clay minerals, quartz, dolomite, as the non-clay minerals. fig. 3. tanuma shale mineralogy obtained by the x-ray diffraction 2.4. shale chemical the x-ray fluorescence instrument (xrf) test was carried out for the purpose of analyzing the shale geochemical. the cuttings were prepared by washing the cuttings samples with water and drying them with electrical over 105 ºc for up to 2.5 hours. the cuttings were crushed and milled to a fine powder for the accuracy of the results. the power was pressed to pellets by applying 5 tons with the piston. the pellets were then analyzed and evaluated for each formation. the chemical compositions of tanuma shale are mainly containing silicon dioxide (sio2) 34.28 %, calcium oxide (cao) 17.1 %, aluminum oxide (al2o3) 13.26 %, iron (iii) oxide (fe2o3) 6.831 %, potassium oxide (k2o) 2.229 % and 1.973 % and 1.433 % of sodium oxide (na2o) and magnesium oxide (mgo) respectively. 2.5. cation exchange capacity test the compensating cation(s) which adsorbed on the surface of a unit layer might be exchanged with other cations. this process is referred to as the clay exchangeable cations. the cations are exchanging with the other cations because of the interaction with the ions in aqueous fluids and it could also be intricate with non-aqueous solutions. the cation exchange capacity (cec) method is a specific method to investigate shale reactivity with mud [10]. ideally, the oil and gas industry accept the methylene blue test (mbt) to measure the cec. api recommendation is about using one gram of finely ground dried shale for the assessment of shale reactivity level [11]. the sample is placed in deionized water with the dispersant, the sulfuric, and the hydrogen peroxide. the sample solution is then heated up gently until a few minutes, cooled down to room temperature, then added to methylene blue fluid. the mbt stops if a drop from the solution of the sample suspension is placed on the filter paper which results in a faint blue halo surrounding the dyed solids. the shale is considered reactive when the cec is high and vis vera while the sandstone and limestone ideally are non-active rocks [5]. however, the active shale is higher than 20 meg/ 100 g and the moderately reactive shale is ranged between 10 to 20 meg/100 g while the low cec can still be a problematic rock if there are small amounts of active clays for swelling which lead for breaking down the shale apart. the results from the cation exchange capacity (cec) tests, for tanuma formation, are 12.5 milliequivalents per gram, as shown in fig.4. based on that, tanuma is classified as moderate to moderately high reactive clay [12]. f. h. alshibli and a. a. a. alrazzaq / iraqi journal of chemical and petroleum engineering 23,3 (2022) 35 41 38 fig. 4. cation exchange capacity test for tanuma formation 2.6. capillary suction timer test the cst technique measures the required time for the slurry to move through a known space on a thick-porous filter paper. the test was acclimatized to measure capillary, suction time, for clay or shale, slurries. the experimental can be done on cuttings, caving, and core to estimate clay reactivity [13]. the cst test requires 3 grams of ground and dry shale cuttings mixed, with the water, brine, mud, or any, designed mud filtration in a small blender cup to create the colloidal suspension. the test is studying the filtration characteristics of the slurry by utilizing the pressure of capillary suction of the filtrate porous paper. the filtration rate, which is spreading away from suspension, will be mainly controlled by suspension filterability. ideally, several tests can be run with different concentrations of salt, and it is well known to repeat the tests to compare the outputs of the numerical, results in seconds [14]. usually, the flocculation concentration of salt can be measured which is dramatically lower than the cst. additionally, the low salt concentration in the fluid will cause the shale particles to disperse into the fluid because of the higher flocculation concentration [5]. fig. 5 as shown , the results of the capillary suction time (cst) that was conducted for tanuma samples. the tests were carried out to measure the effect of the nominated test fluids, with different salt concentrations, on both formations. to estimate the reactivity nature of tanuma and zubair shale formations, tanuma formation needed 8 % of kcl until recording the lowest cst timing which is 24 seconds. the same sample of shale was recorded for 335 seconds when it was in contact with deionized water. thus, the shale reactivity can be rectified by adding 8 % of kcl inhibitor into the drilling mud. this kcl concentration is considered the optimal point. otherwise, the timing will be higher if the kcl is below or above the optimal point. fig. 5. capillary suction time for tanuma shale formation 2.7. shale swelling test the swelling test is carried out by using the linear swelling meter (lsm) technique. this technique is measuring the free swelling, of, a reconstituted, pellet of shale after it was in contact with the fluid which shows the tendency of shale rock sample to hydration or dehydration. it is considered a proper technique for testing the shale reactivity checks. the swelling measurement, which is the shale uptake, represents the shale reactivity to the mud used in the test [15]. the swelling test is considered a good indication of the shale reactivity to the fluids being tested. if more, of shale swelling is observed, in the water that means it has a high sensitivity to water. the result of this test is generally associated with chemical reactivity and some of the physical effects, e.g., fractures or cracks [5], [16]. based on the outcome of the capillary suction time (cst) test, as well as the other tests, the decision was made to design two formulations of water-based muds (wbm) with different shale inhibitor agents to rectify the shale swelling issue in tanuma shale. the formulations of the water-based mud for the first mud (1st mud) were formulated with the additives (polyglycol, phpa, and asphaltite) and the second mud (2nd mud) was formulated with dispersion and hydration suppressant (which is basically poly amino acid hydration suppressant). the kcl percent, in both formulated muds, is 8 % for tanuma shale. the filtration controls and the asphaltite are selected based on the sem results to plug the micro-fractures and poses present in the shale rocks. as shown in fig. 6 for tanuma shale, both muds needed around 20 hours before the relatively positive stabilization where the shale expanded by about 2.5 % with the first mud and 1.5 with the 2nd mud after the 20 hours. at the end of the test, the shale expansion became 3.2 % with the 1st mud and 2 % with the 2nd mud. f. h. alshibli and a. a. a. alrazzaq / iraqi journal of chemical and petroleum engineering 23,3 (2022) 35 41 39 fig. 6. linear swelling test of tanuma shale 3discussion tanuma shale samples are tested with different laboratory methods to investigate the root causes of its reactivity when it is in contact with drilling mud. the visual inspection indicated the presence of clay minerals the presents of chlorite and kaolinite and possible illite according to its color, laminae, and calcareous features [17]. the geochemical (xrf test) analysis showed a higher percentage and more kinds of chemicals al, ca, fe2o, and k2o which refer to the presence of clay. the xrd confirmed that tanuma shale contains clay (illite, chlorite, kaolinite, and palygorskite) which are nonswelling clays in their nature. but the illite and chlorite can slightly swell fluid when they expose to altering from drilling operations and this tendency is occur more in illite than chlorite clay. illite clay contains the weakly-bond interlayer cations and weakly layer charges that lead to swelling and dispersion when in contact with water. it is also worth noting that the presence of the larger amount of illite and chlorite clays is causing serious problems of instability. the kaolinite clay is a tight layer type that does not exchange unless broken bonds occur which cause minor cations exchange. the microfractures and pores in the structure of tanuma shale, observed by the sem, will always present the wellbore instability issues resulting from the raises in the pore pressure. the size and the amount of the microfractures and pores are significant. the xrd and cec tests approved the reactivity of shale are matching xrd and xrf results. the capillary suction time (cst) method confirmed the reactivity and the category of shale reactivity. it is observed that in testing the shales with di water, the level of cst is higher than 150 seconds, which means the shales of tanuma formation clay particles disperse into the fluid. but, when continue adding the kcl, the cst readings dramatically decreased until reaching to the equilibrium level with the flocculation concentration. the presence of a large amount of illite (the weak-bond layer type) and chlorite clay in tanuma shale has affected the salt consumption until achieving the equilibrium point with the water intake and k+ exchange which is at 8 %. 4conclusions tanuma formation is moderately active shale, and it tends to disperse in the fluid, especially with fresh water. tanuma shale failure can be managed by using polymer mud with a combination of 8 % kcl, filtration control additives, and other shale inhibitors. the mud with poly amino acid was the most optimum shale inhibitor for tanuma formation compared to the glycol and asphaltites inhibitors. references [1] m. lal, "shale stability: drilling fluid interaction and shale strength." in spe asia pacific oil and gas conference and exhibition. onepetro, 1999. [2] b. s. aadnoy, and r. looyeh. petroleum rock mechanics: drilling operations and well design. gulf professional publishing, 2019. [3] f. k. mody, and h. h. arthur, "borehole-stability model to couple the mechanics and chemistry of drilling-fluid/shale interactions." journal of petroleum technology45.11 1993, pp. 1093-1101. [4] s. gomez, and w. he, "fighting wellbore instability: customizing drilling fluids based on laboratory studies of shale-fluid interactions." iadc/spe asia pacific drilling technology conference and exhibition. onepetro, 2012. [5] m. stephens, s. gomez, and m. churan, "laboratory methods to assess shale reactivity with drilling fluids." aade national technical conference, new orleans, 2009. [6] a. k. abbas, r. e. flori. a. al-anssari, and m. alsaba, "testing and evaluation of shale stability for zubair shale formation." in spe kingdom of saudi arabia annual technical symposium and exhibition. onepetro, 2018. [7] m. lal, "shale stability: drilling fluid interaction and shale strength." spe asia pacific oil and gas conference and exhibition. onepetro, 1999. [8] m. e. chenevert, and a. k. sharma, "permeability and effective pore pressure of shales." spe drilling & completion8.01 1993, pp. 28-34. [9] s. gomez, and w. he, "laboratory method to evaluate fracture development in hard shale formations exposed to drilling fluids." proceedings of aade fluid conference. houston. 2006. [10] a. babajide, o. adebowale, f. adesina, a. churchill, and m. ifechukwu, "effects of temperature and pressure on shale cuttings dispersion in water based mud wbm using nacl, cacl2, kcl salts as primary inhibiting agents and polymer xcd xanthan gum as the secondary inhibiting agent." spe nigeria annual international conference and exhibition. onepetro, 2016. https://onepetro.org/speapog/proceedings-abstract/99apogce/all-99apogce/spe-54356-ms/59765 https://onepetro.org/speapog/proceedings-abstract/99apogce/all-99apogce/spe-54356-ms/59765 https://onepetro.org/speapog/proceedings-abstract/99apogce/all-99apogce/spe-54356-ms/59765 https://books.google.com/books?hl=en&lr=&id=xzaddwaaqbaj&oi=fnd&pg=pp1&dq=%5b2%5d%09b.+s.+aadnoy,+and+r.+looyeh.+petroleum+rock+mechanics:+drilling+operations+and+well+design.+gulf+professional+publishing,+2019.&ots=hsxhvinzy2&sig=h-g9c02kgy5l-6gjoywiact1oi4 https://books.google.com/books?hl=en&lr=&id=xzaddwaaqbaj&oi=fnd&pg=pp1&dq=%5b2%5d%09b.+s.+aadnoy,+and+r.+looyeh.+petroleum+rock+mechanics:+drilling+operations+and+well+design.+gulf+professional+publishing,+2019.&ots=hsxhvinzy2&sig=h-g9c02kgy5l-6gjoywiact1oi4 https://books.google.com/books?hl=en&lr=&id=xzaddwaaqbaj&oi=fnd&pg=pp1&dq=%5b2%5d%09b.+s.+aadnoy,+and+r.+looyeh.+petroleum+rock+mechanics:+drilling+operations+and+well+design.+gulf+professional+publishing,+2019.&ots=hsxhvinzy2&sig=h-g9c02kgy5l-6gjoywiact1oi4 https://onepetro.org/jpt/article-abstract/45/11/1093/69997 https://onepetro.org/jpt/article-abstract/45/11/1093/69997 https://onepetro.org/jpt/article-abstract/45/11/1093/69997 https://onepetro.org/jpt/article-abstract/45/11/1093/69997 https://onepetro.org/speapdt/proceedings/12apdt/spe-155536-ms/155750 https://onepetro.org/speapdt/proceedings/12apdt/spe-155536-ms/155750 https://onepetro.org/speapdt/proceedings/12apdt/spe-155536-ms/155750 https://onepetro.org/speapdt/proceedings/12apdt/spe-155536-ms/155750 https://onepetro.org/speapdt/proceedings/12apdt/spe-155536-ms/155750 https://onepetro.org/speapdt/proceedings/12apdt/spe-155536-ms/155750 https://onepetro.org/spesats/proceedings-abstract/18sats/all-18sats/spe-192274-ms/215617 https://onepetro.org/spesats/proceedings-abstract/18sats/all-18sats/spe-192274-ms/215617 https://onepetro.org/spesats/proceedings-abstract/18sats/all-18sats/spe-192274-ms/215617 https://onepetro.org/spesats/proceedings-abstract/18sats/all-18sats/spe-192274-ms/215617 https://onepetro.org/spesats/proceedings-abstract/18sats/all-18sats/spe-192274-ms/215617 https://onepetro.org/speapog/proceedings-abstract/99apogce/all-99apogce/spe-54356-ms/59765 https://onepetro.org/speapog/proceedings-abstract/99apogce/all-99apogce/spe-54356-ms/59765 https://onepetro.org/speapog/proceedings-abstract/99apogce/all-99apogce/spe-54356-ms/59765 https://onepetro.org/dc/article/8/01/28/70622 https://onepetro.org/dc/article/8/01/28/70622 https://onepetro.org/dc/article/8/01/28/70622 https://onepetro.org/spenaic/proceedings-abstract/16naic/all-16naic/spe-184310-ms/192736 https://onepetro.org/spenaic/proceedings-abstract/16naic/all-16naic/spe-184310-ms/192736 https://onepetro.org/spenaic/proceedings-abstract/16naic/all-16naic/spe-184310-ms/192736 https://onepetro.org/spenaic/proceedings-abstract/16naic/all-16naic/spe-184310-ms/192736 https://onepetro.org/spenaic/proceedings-abstract/16naic/all-16naic/spe-184310-ms/192736 https://onepetro.org/spenaic/proceedings-abstract/16naic/all-16naic/spe-184310-ms/192736 https://onepetro.org/spenaic/proceedings-abstract/16naic/all-16naic/spe-184310-ms/192736 https://onepetro.org/spenaic/proceedings-abstract/16naic/all-16naic/spe-184310-ms/192736 f. h. alshibli and a. a. a. alrazzaq / iraqi journal of chemical and petroleum engineering 23,3 (2022) 35 41 40 [11] american petroleum institute. recommended practice for laboratory testing of drilling fluids. american petroleum institute, 2009. [12] m. n. garcia, f. sorenson, j.c. bonapace, f. motta, c. bajuk, and h. stockman, "vaca muerta shale reservoir characterization and description: the starting point for development of a shale play with very good possibilities for a successful project." unconventional resources technology conference. society of exploration geophysicists, american association of petroleum geologists, society of petroleum engineers, 2013. [13] r. d. wilcox, j. v. fisk, and g. e. corbett, "filtration method characterizes dispersive properties of shales." spe drilling engineering 2.02 1987, pp. 149-158. [14] d. benoit, g. r. montenegro-galindo, k. l. anderson, and k. w. hoeman, k. w, "obtaining comparable and relevant formation swelling sensitivity data from cst: is this even possible?." spe international conference and exhibition on formation damage control. onepetro, 2016. [15] i. baroid drilling fluids, "baroid fluids handbook." houston, usa, 1998. [16] s. wysocki, r. wisniowski, d. ryzan, m. gaczol, "linear swelling test (lst) of clay formation under the influence of newly developed drilling fluids with the addition of cationic polymers." agh drilling, oil, gas 32.4, 2015. [17] m. asef, and m. farrokhrouz, "shale engineering: mechanics and mechanisms." crc press, 2013. https://library.seg.org/doi/abs/10.1190/urtec2013-090 https://library.seg.org/doi/abs/10.1190/urtec2013-090 https://library.seg.org/doi/abs/10.1190/urtec2013-090 https://library.seg.org/doi/abs/10.1190/urtec2013-090 https://library.seg.org/doi/abs/10.1190/urtec2013-090 https://library.seg.org/doi/abs/10.1190/urtec2013-090 https://library.seg.org/doi/abs/10.1190/urtec2013-090 https://library.seg.org/doi/abs/10.1190/urtec2013-090 https://library.seg.org/doi/abs/10.1190/urtec2013-090 https://onepetro.org/dc/article/2/02/149/75098 https://onepetro.org/dc/article/2/02/149/75098 https://onepetro.org/dc/article/2/02/149/75098 https://onepetro.org/dc/article/2/02/149/75098 https://onepetro.org/spefd/proceedings/16fd/d012s007r001/187007 https://onepetro.org/spefd/proceedings/16fd/d012s007r001/187007 https://onepetro.org/spefd/proceedings/16fd/d012s007r001/187007 https://onepetro.org/spefd/proceedings/16fd/d012s007r001/187007 https://onepetro.org/spefd/proceedings/16fd/d012s007r001/187007 https://onepetro.org/spefd/proceedings/16fd/d012s007r001/187007 https://onepetro.org/spefd/proceedings/16fd/d012s007r001/187007 https://yadda.icm.edu.pl/yadda/element/bwmeta1.element.baztech-e3a2afe9-35bf-40a9-bda7-b55015246365/c/wysocki_drilling_4_2015.pdf https://yadda.icm.edu.pl/yadda/element/bwmeta1.element.baztech-e3a2afe9-35bf-40a9-bda7-b55015246365/c/wysocki_drilling_4_2015.pdf https://yadda.icm.edu.pl/yadda/element/bwmeta1.element.baztech-e3a2afe9-35bf-40a9-bda7-b55015246365/c/wysocki_drilling_4_2015.pdf https://yadda.icm.edu.pl/yadda/element/bwmeta1.element.baztech-e3a2afe9-35bf-40a9-bda7-b55015246365/c/wysocki_drilling_4_2015.pdf https://yadda.icm.edu.pl/yadda/element/bwmeta1.element.baztech-e3a2afe9-35bf-40a9-bda7-b55015246365/c/wysocki_drilling_4_2015.pdf https://books.google.com/books?hl=en&lr=&id=ztyr4ayksmcc&oi=fnd&pg=pp1&dq=%5b17%5d%09m.+asef,+and+m.+farrokhrouz,+%22shale+engineering:+mechanics+and+mechanisms.%22+crc+press,+2013.&ots=wqspw0dfil&sig=vzuu1hmfp0clopaxkfmzymcotky https://books.google.com/books?hl=en&lr=&id=ztyr4ayksmcc&oi=fnd&pg=pp1&dq=%5b17%5d%09m.+asef,+and+m.+farrokhrouz,+%22shale+engineering:+mechanics+and+mechanisms.%22+crc+press,+2013.&ots=wqspw0dfil&sig=vzuu1hmfp0clopaxkfmzymcotky https://books.google.com/books?hl=en&lr=&id=ztyr4ayksmcc&oi=fnd&pg=pp1&dq=%5b17%5d%09m.+asef,+and+m.+farrokhrouz,+%22shale+engineering:+mechanics+and+mechanisms.%22+crc+press,+2013.&ots=wqspw0dfil&sig=vzuu1hmfp0clopaxkfmzymcotky f. h. alshibli and a. a. a. alrazzaq / iraqi journal of chemical and petroleum engineering 23,3 (2022) 35 41 41 الفحوصات المختبرية التقيميه لتفاعل الصخر الطفل مع الطين لتكوين التنومة في جنوب العراق و اياد عبدالحليم فاضل حميد علي اادبغجامعة الخالصة يعد فشل الصخور أثناء الحفر مشكلة مهمة يجب حلها في تكنولوجيا البترول. أحد أكثر أسباب انهيار الصخور هو التفاعل الكيميائي الصخري مع سوائل الحفر. في العديد من حقول النفط في جنوب العراق ، ر المستقر. فهم التفاعالت ُيعرف الحفر من خالل تكوين تنومة بأنه أكثر العمليات تحدًيا نظًرا لسلوكه غي من خالل فحص خواص التكوين وسلوكه مع طين الحفر. يجب يتم الكيميائية بين صخر الطفل و سائل الحفر تقليل التفاعالت الكيميائية عن طريق اختيار طين حفر مناسب مع إضافات كيميائية فعالة. يصف هذا البحث الطرق العملية المستخدمة لتقييم واختبار عدم استقرار تكوين الطفل أثناء عمليات الحفر. تم جمع عينات من ستهدف واستخدم لتصنيف مستويات تفاعل التكوين واإلضافات المطلوبة لمنع عدم استقرار الطين. التكوين الم تشمل هذه االختبارات الطريقة الوصفية مع األساليب التحليلية المختلفة باستخذام معدات مختبريه قياسيه. هذه راف ، وفلورة األشعة السينية ، ، األشعة السينية ذات انح (sem)االختبارات هي مجهر المسح اإللكتروني كما تم إجراء اختبار مقياس االنتفاخ الخطي (.cst)، واختبار مؤقت الشفط الشعري (cec)وتبادل الكاتيون (lsm) لتعزيز خطة التطوير. يحتوي تكوين تنومة على طين نشط بشكل معتدل مع وجود كسور دقيقة ومسام ٪ من مثبطات غير عضوية )على سبيل المثال 8خدام طين بوليمر مع دقيقة في شكله. ويمكن التحكم فيه باست ،kcl.ومضافات موانع الترشيح، ومانع ترطيب حمض أميني الذي أظهر أدنى نسبة انتفاخ ، ) الكلمات الدالة: صخور الطفل، صخور التنومه ، فشل صخور لطفل ، انتفاخ صخور الطفل ، ، تفاعل صخور الطفل available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.21 no.3 (september 2020) 51 – 55 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name : mohannad a. raheem , email: mohannad10a@gmail.com, name: raghad f. qassim, email: rfkalm@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. performance comparison between recycled single stage and double stage hydrocyclones mohannad a. raheem and raghad f. qassim college of engineering – university of baghdad abstract this research presents a comparison of performance between recycled single stage and double stage hydrocyclones in separating water from water/kerosene emulsion. the comparison included several factors such as: inlet flow rate (3,5,7,9, and 11 l/min), water feed concentration (5% and 15% by volume), and split ratio (0.1 and 0.9). the comparison extended to include the recycle operation; once and twice recycles. the results showed that increasing flow rate as well as the split ratio enhancing the separation efficiency for the two modes of operation. on the contrary, reducing the feed concentration gave high efficiencies for the modes. the operation with two cycles was more efficient than one cycle. the maximum obtained efficiencies were 97% and 97.5% at 5% concentration, 11 l/min, and 0.9 split ratio for twice recycled single stage and double stage hydrocyclones, respectively. the pressure drop was the same for the two modes of operation. it was concluded that using recycled single stage hydrocyclone was more economical since it reduced the cost of additional hydrocyclone. keywords: hydrocyclone, kerosene, separation efficiency, split ratio received on 04/03/2020, accepted on 25/06/2020, published on 30/09/2020 https://doi.org/10.31699/ijcpe.2020.3.7 1introduction water-in-oil emulsions are commonly found in the petroleum industry, for example in petroleum refineries and pipeline transportation stations[1]. the crude oil production containing emulsified water poses problems, such as the corrosion of transport systems and catalyst poisoning during the refining phase. the simplicity of extracting petroleum water differs with the aging of the emulsion[2]. most of free water can be removed by simple settling. the other two forms need more effective separation like operating at high temperature, centrifugal separation, vacuum dehydration, coalescing filtration and bleed from bottom of oil compartment. centrifugal separation is an efficient way to maintain the lubricant's free water cleanliness and most emulsified liquid [3] and this can be done by using liquid-liquid hydrocyclone. because produced oil is often accompanied by significant amounts of water, it is important to provide separation facilities for oil and water before selling the oil. the oil industry has been turning to the use of hydrocyclone to satisfy this need[4]. conventional hydrocyclone (two-product) are used for various applications, including sorting, thickening, de-slimming and dewatering[5]. current hydrocyclone water oil separation mainly uses specific centrifugal forces between oil and water to achieve rapid separation[6].osei and al-kayiem[7] presented an experimental study of a liquid–liquid hydrocyclone to separate oil from oil/water emulsion with 90% water cut at different flow rates and temperatures. the results showed that the percentage separation efficiency was higher than 80% in the flow split ratio between 0.6-0.7 for all the flow and temperature cases. fluid temperature slightly impacted the hydrocyclone performance and the pressure drop ratio inversely affected the separation efficiency. bram et al. [8] use cfd models to study several aspects of deoiling hydrocyclone and thus enabling model-based control. they experimentally validated their original and modified models using a pilot plant hydrocyclone. it was shown that the modified model performed better during all the tests. schummer, noe, and baker [9] investigated the axial and tangential velocity fields inside a rotating wall hydrocyclone using low doppler velocimetry (ldv) measurements aiming at oil/water separation. velocity measurements showed the influence of rotation speed and flow rate on the resulting acceleration field but the tangential profiles barely affected by flow withdrawal through an annular downstream exit [10]. in this study, it was intended to get more efficient separation of water/kerosene emulsion than using only one hydrocyclone. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:mohannad10a@gmail.com mailto:rfkalm@yahoo.com http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2020.3.7 m. a. raheem and r. f. qassim / iraqi journal of chemical and petroleum engineering 21,3 (2020) 51 55 52 produced kerosene treating equipment performance is commonly described in terms of its “water removal efficiency.” this efficiency considers only the removal of dispersed water[11]. split ratio, f= 𝑄𝑜 𝑄𝑖 (1) [12] where: 𝑄𝑜 is overflow rate (l/min) and 𝑄𝑖 is inlet flow rate (l/min). percentage separation efficiency, %e=1 𝐶𝑜 𝐶𝑖 × 100% (2) [12] where: 𝐶𝑜 is overflow water concentration (ppm) and 𝐶𝑖 is inlet water concentration (ppm). pressure drop, ∆𝑝 = 𝑝𝑖 − 𝑝𝑜 (3) where: 𝑝𝑖 is the inlet pressure (bar) and 𝑝𝑜 is the overflow pressure (bar). 2experimental work 2.1. materials and equipment a. materials kerosene (from local market). ethanol (abs.100% hplc grade, belgium). b. equipment pump no.1 (streen centrifugal electro-pump model stpa5, qmax=65 l/min, hmax=56m, hp=1.5) pump no.2 (stronger water pump qb60, qmax=30 l/min, hmax=30 m, hp=0.5) hydrocyclone (locally designed and fabricated) uv spectrophotometer genesis 10 uv (0-3) absorbance, usa. pressure gage, (0-8) bar, china. homogenizer, ultra turrax, 10000 rpm, germany. 2.2. experimental procedures a. recycled single stage hydrocyclone fig. 1 shows the experimental set-up. by closing valve 6 and opening valve 2 the second hydrocyclone was omitted and the operation was done by one hydrocyclone only. the overflow was recycled once and twice. the concentration of water in the feed was changed (5% and 15%). at each concentration the feed flow rate was changed (3, 7, and 11 l/min). the split ratio was also changed (0.1 and 0.9) for each concentration. the concentrations of water in kerosene were measured in the overflow and in the underflow using uvspectrophotometer for each experiment in single and double cycles. b. double stage hydrocyclone the experimental procedure began by connecting the two hydrocyclones in series, the overflow of the first hydrocyclone entered the second one as feed. so, it could offer two-stage separation process. again, the two pumps were connected in series to the hydrocyclone inlet. by closing valve 2 and opening valve 6 these pumps pushed the water-oil feed emulsion from the feed tank to the two hydrocyclones in series and this action provided a suitable centrifugal force to make a good separation of water from oil in two stages. the feed flow rate was changed (3,5,7,9, and 11 l/min) for each water feed concentration (5% and 15%) each at two split ratios (0.1 and 0.9). as mentioned before the concentrations of water in kerosene were measured using uvspectrophotometer. fig. 1. experimental set-up 3results and discussion the results obtained from the experiments were presented as follows: 3.1. effect of flow rate on separation efficiency for recycled single stage hydrocyclone the effect of flow rate on percentage separation efficiency for water concentrations 5% and 15% at split ratio 0.9 using once and twice recycled single stage hydrocyclone is presented in fig. 2. it is obvious from the figure the direct effect of flow rate on the percentage separation efficiency for all cases. this behavior was attributed to increasing the centrifugal force in the hydrocyclone with increasing flow rate. the lowest effect noticed was at 15% water concentration for one recycle operation. this might be because of the high concentration of water in the feed that did not show a noticeable removal of water as the flow rate increased. the percentage separation efficiencies were in the order: 5% concentration of two recycles, 5% concentration of one recycle, 15% of two cycles, and 15% of one recycle. so, the effect of two recycles was very obvious except at the highest flow rate 11 l/min for 5% concentration. m. a. raheem and r. f. qassim / iraqi journal of chemical and petroleum engineering 21,3 (2020) 51 55 53 it was noted that the maximum percentage separation efficiency 97% was achieved equally well at 5% concentration for one and two cycles at the highest flow rate, 11 l/min. that is because at the highest flow rate the ratio of water molecules emerged from the overflow were the same for one and two cycles, no further water molecules could be emerged because of the low inlet concentration. in 15% concentration case the enhancement was clear because of the large amount of water molecules in the feed. fig. 2. effect of flow rate on separation efficiency at 0.9 split ratio for once and twice recycled single stage hydrocyclone: (1) refers to one cycle and (2) refers to two cycles the comparison between the percentage separation efficiencies at 5% and 15% water concentrations revealed the superiority of the separation at 5% concentration. this is because the amount of water removed at 5% concentration was comparable to that presented in the feed which was not the case at15% concentration case. this discussion makes it clear that working twice recycled single stage hydrocyclone at high flow rate is recommended for separating high water concentration but for low water concentration only one recycle is adequate to give high percentage separation efficiency at high flow rate. 3.2. effect of flow rate on separation efficiency for double stage hydrocyclone it was shown in fig.4. that the efficiencies of removing water from water-kerosene emulsion for 5% and 15% water concentrations at split ratio 0.1 in the double stage hydrocyclone were approximately coincident at flow rates (3,5,7, and 9 l/min). the percentage separation efficiencies of 15% concentration were slightly higher than those for 5% concentration at these flow rates. that was because the use of two stages of separation made further separation of water from the emulsion and gave some enhancement in the case 15% concentration because of the large amount of water in the feed but in the case of 5% concentration no further separation occurred because of low water concentration. at the highest flow rate used in the experiments, 11 l/min, the situation was reversed, namely the separation efficiency of 5% concentration 92.2 % became clearly higher than that for 15% concentration 85.9%. it was the maximum removal efficiency in this case. the reason behind this was because 0.1 split ratio made the overflow outlet so narrow that water molecules escaped from overflow opening for 15% concentration were comparable to that for 5% concentration at low and moderate flow rates. little enhancement at 15% concentration was observed. when the flow rate increased to the highest value, the strong vortices offered very big centrifugal force that enabled more water molecules to escape from the overflow leading to decreased separation efficiency at 15% concentration. because the escaped molecules formed higher ratio with respect to the inlet concentration in the case of 15% concentration than that in the case of 5% concentration the percentage separation efficiency was noticeably enhanced at 5% concentration. from this argument it is recommended to adopt the double stage hydrocyclone for high water concentrations when the split ratio is low. fig. 3. effect of flow rate on efficiency at 0.1 split ratio for double stage hydrocyclone when the split ratio increased from 0.1 to 0.9, the overflow opening was wider than for 0.1 split ratio giving broader way for the water molecules to escape from overflow outlet. water molecules in the feed of 15% concentration were more than those for 5% concentration, so the molecules escaped were also more leading to decreased separation efficiency at all flow rates as illustrated in fig.5. therefore, the efficiencies of 5% concentration were higher than those of 15% concentration. the effect of flow rate was also noticed in fig. 4, the removal of water increased with the increase of the flow rate and the maximum removal value 97.5% was at 11 l/min for 5% water concentration. another finding could be extracted from fig. 4 in comparison with fig. 3. that the values of percentage separation efficiencies in fig.5 were higher than those of fig. 3 for 5% concentration but they were lower for 15% concentration. this was explained through the variation of split ratio. the split ratio affected the overall performance of the separation by interaction with the inlet concentration. m. a. raheem and r. f. qassim / iraqi journal of chemical and petroleum engineering 21,3 (2020) 51 55 54 as the split ratio increased there was a chance for more water molecules to run away from the overflow opening. when water molecules existed at high concentration in the feed the chance was bigger than at low concentration. according to this explanation using double stage hydrocyclone is essential for low concentration and high split ratio but when the concentration is higher, low split ratio must be used. fig. 4. effect of flow rate on efficiency at 0.9 split ratio for double stage hydrocyclone 3.3. effect of flow rate on pressure drop fig. 5 shows the dependence of pressure drop on flow rate for both twice recycled single stage hydrocyclone and double stage hydrocyclone at 5% concentration and 0.9 split ratio. it was clear that both of them had the same pressure drop for all flow rates. the pressure drops related to energy consumption. so, there was no preference between the two modes of operation from energy consumption aspect. fig. 5. effect of flow rate on pressure drop at 5% water feed concentration and 0.9 split ratio 4conclusions from this study it was evident that adopting recycling mode of operation greatly enhanced the separation than using single hydrocyclone. as the cycles increased the enhancement of separation increased. in comparison between the maximum separation efficiencies obtained using twice recycled single stage hydrocyclone 97% and double stage hydrocyclone 97.5% each at 5% concentration, 11 l/min, and 0.9 split ratio, it was clear that the difference between them was insignificant. furthermore, the pressure drop was also identical. therefore, it was concluded that using recycled single stage hydrocyclone was more economical since it reduced the cost of constructing another hydrocyclone. references [1] s. a. m. mohammed and m. s. mohammed, “the application of microwave technology in demulsification of water-in-oil emulsion for missan oil fields,” iraqi j. chem. pet. eng., no. march, 2013. [2] d. c. maia filho, j. b. v. s. ramalho, l. s. spinelli, and e. f. lucas, “aging of water-in-crude oil emulsions: effect on water content, droplet size distribution, dynamic viscosity and stability,” colloids surfaces a physicochem. eng. asp., vol. 396, pp. 208–212, 2012 [3] r garvey, g fogel, "estimating water content in oils: moisture in solution, emulsified water, and free water". joint oil analysis program pensacola fltechnical support center, 1996. [4] d. l. taggart, s. l. andrews, and j. r. worrell, “oilwater separation using hydrocyclones: an experimental search for optimum dimensions.,” vol. 11, no. 93, pp. 37– 50, 1994. [5] mm ahmed, ga ibrahim, mg farghaly, "performance of a three-product hydrocyclone." international journal of mineral processing 91, no. 1-2 (2009): 34-40. [6] l. liu, l. zhao, x. yang, y. wang, b. xu, and b. liang, “innovative design and study of an oil-water coupling separation magnetic hydrocyclone,” sep. purif. technol., 2018 [7] j. e. hamza, h. h. al-kayiem, and t. a. lemma, “experimental investigation of the separation performance of oil/water mixture by compact conical axial hydrocyclone,” therm. sci. eng. prog., p. 100358, 2019 [8] m. v. bram, l. hansen, d. s. hansen, and z. yang, “extended grey-box modeling of real-time hydrocyclone separation efficiency,” 2019 18th eur. control conf. ecc 2019, pp. 3625–3631, 2019 [9] p. schummer, p. noe, and m. baker, “ldv measurements in the vortex flow created by a rotating wall dewatering cyclone,” 1992, pp. 359–376. [10] mi chasib,and rf qasim, "design and experimental study of two-stage hydrocyclones for oil-water separation." journal of engineering and applied sciences 14, no. 18 (2019): 6890-6896. [11] a. f. al-alawy and s. m. al-musawi, “microfiltration membranes for separating oil / water emulsion,” iraqi j. chem. pet. eng., vol. 14, no. 4, pp. 53–70, 2013. [12] r. s. mathiravedu, s. wang, r. s. mohan, o. shoham, and j. d. marrelli, “performance and control of liquid-liquid cylindrical cyclone separators,” j. energy resour. technol. trans. asme, vol. 132, no. 1, pp. 0110011–0110019, 2010 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/310 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/310 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/310 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/310 https://www.sciencedirect.com/science/article/abs/pii/s0927775712000052 https://www.sciencedirect.com/science/article/abs/pii/s0927775712000052 https://www.sciencedirect.com/science/article/abs/pii/s0927775712000052 https://www.sciencedirect.com/science/article/abs/pii/s0927775712000052 https://www.sciencedirect.com/science/article/abs/pii/s0927775712000052 https://www.researchgate.net/publication/235027124_estimating_water_content_in_oils_moisture_in_solution_emulsified_water_and_free_water https://www.researchgate.net/publication/235027124_estimating_water_content_in_oils_moisture_in_solution_emulsified_water_and_free_water https://www.researchgate.net/publication/235027124_estimating_water_content_in_oils_moisture_in_solution_emulsified_water_and_free_water https://www.researchgate.net/publication/235027124_estimating_water_content_in_oils_moisture_in_solution_emulsified_water_and_free_water https://www.sciencedirect.com/science/article/abs/pii/0920410594900612 https://www.sciencedirect.com/science/article/abs/pii/0920410594900612 https://www.sciencedirect.com/science/article/abs/pii/0920410594900612 https://www.sciencedirect.com/science/article/abs/pii/0920410594900612 https://www.sciencedirect.com/science/article/abs/pii/s0301751608002068 https://www.sciencedirect.com/science/article/abs/pii/s0301751608002068 https://www.sciencedirect.com/science/article/abs/pii/s0301751608002068 https://www.sciencedirect.com/science/article/pii/s1383586618301072 https://www.sciencedirect.com/science/article/pii/s1383586618301072 https://www.sciencedirect.com/science/article/pii/s1383586618301072 https://www.sciencedirect.com/science/article/pii/s1383586618301072 https://www.sciencedirect.com/science/article/abs/pii/s2451904918306085 https://www.sciencedirect.com/science/article/abs/pii/s2451904918306085 https://www.sciencedirect.com/science/article/abs/pii/s2451904918306085 https://www.sciencedirect.com/science/article/abs/pii/s2451904918306085 https://www.sciencedirect.com/science/article/abs/pii/s2451904918306085 https://ieeexplore.ieee.org/abstract/document/8796175 https://ieeexplore.ieee.org/abstract/document/8796175 https://ieeexplore.ieee.org/abstract/document/8796175 https://ieeexplore.ieee.org/abstract/document/8796175 https://link.springer.com/chapter/10.1007/978-94-015-7981-0_22 https://link.springer.com/chapter/10.1007/978-94-015-7981-0_22 https://link.springer.com/chapter/10.1007/978-94-015-7981-0_22 https://www.researchgate.net/profile/raghad_almilly2/publication/334491813_design_and_experimental_study_of_two-stage_hydrocyclones_for_oil-water_separation/links/5d2df214299bf1547cbc92e8/design-and-experimental-study-of-two-stage-hydrocyclones-for-oil-water-separation.pdf https://www.researchgate.net/profile/raghad_almilly2/publication/334491813_design_and_experimental_study_of_two-stage_hydrocyclones_for_oil-water_separation/links/5d2df214299bf1547cbc92e8/design-and-experimental-study-of-two-stage-hydrocyclones-for-oil-water-separation.pdf https://www.researchgate.net/profile/raghad_almilly2/publication/334491813_design_and_experimental_study_of_two-stage_hydrocyclones_for_oil-water_separation/links/5d2df214299bf1547cbc92e8/design-and-experimental-study-of-two-stage-hydrocyclones-for-oil-water-separation.pdf https://www.researchgate.net/profile/raghad_almilly2/publication/334491813_design_and_experimental_study_of_two-stage_hydrocyclones_for_oil-water_separation/links/5d2df214299bf1547cbc92e8/design-and-experimental-study-of-two-stage-hydrocyclones-for-oil-water-separation.pdf http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/326 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/326 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/326 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/326 https://asmedigitalcollection.asme.org/energyresources/article-abstract/132/1/011001/406831 https://asmedigitalcollection.asme.org/energyresources/article-abstract/132/1/011001/406831 https://asmedigitalcollection.asme.org/energyresources/article-abstract/132/1/011001/406831 https://asmedigitalcollection.asme.org/energyresources/article-abstract/132/1/011001/406831 https://asmedigitalcollection.asme.org/energyresources/article-abstract/132/1/011001/406831 m. a. raheem and r. f. qassim / iraqi journal of chemical and petroleum engineering 21,3 (2020) 51 55 55 مقارنة االداء بين الهيدروسايكلون احادي المرحلة بعد تدويرالناتج فيه لمرة واحدة وبين الهايدروسايكلون ثنائي المرحلة مهند عبد الستار رحيم و رغد فريد قاسم قسم الهندسة الكيمياوية –كلية الهندسة –جامعة بغداد الخالصة الناتج منه لمرة واحدة بعد اعادة تدوير البحث مقارنة األداء بين الهيدروسايكلون ذي المرحلة الواحدةيقدم هذا في فصل الماء من مستحلب الماء / الكيروسين. تضمنت المقارنة فقط وبين الهيدروسايكلون ثنائي المرحلة ٪ من حيث 15٪ و 5دقيقة(وتركيزالماء الداخل)\لتر 11،9،7،5،3عدة عوامل مثل: معدل الجريان الداخل ) (. أظهرت النتائج أن زيادة معدل الجريان وكذلك نسبة الفصل تزيد من 0.9و 0.1الحجم( ، ونسبة الفصل ) كفاءة الفصل لكال الطريقتين. كذلك أعطى تقليل تركيز الماء الداخل كفاءة عالية لكلى الحالتين ايظا. كانت دة التدويرللهايدروسايكلون أكثر كفاءة من دورة واحدة لنفس الهيدروسايكلون. كانت أقصى قدر من العملية مع اعا نسبة الفصل 0.9لتر / دقيقة ، و 11٪ ، 5٪ بتركيز 97.5٪ و 97الكفاءة التي تم الحصول عليها لمرحلة على التوالي. كان للهايدروسايكلون ذي المرحلة الواحدة بعد اعادة التدوير والهايدروسايكلون ثنائي ا أحادي المرحلة الهايدروسايكلون انخفاض الضغط هو نفسه بالنسبة لطريقتي التشغيل. وخلصنا إلى أن استخدام .اإلضافي الهايدروسايكلون المعاد تدويره كان أكثر اقتصادا ألنه خفض تكلفة الفصلالكلمات الدالة: هايدروسايكلون ، كيروسين ، كفاءة الفصل ، نسبة available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.20 no.4 (december 2019) 35 – 40 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: karrar ahmed mohammed , email: karrarahmed2002@gmail.com , name: ayad a. al-haleem, email: ayadah62@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. a comparative study of pressure losses and hole cleaning efficiency of water and polymer solutions in horizontal wells karrar ahmed mohammed and ayad a. al-haleem college of engineering-university of baghdad abstract the main objective of this study is to experimentally investigate the effect of the cmc polymeric drag reducer on the pressure drop occurred along the annulus of the wellbore in drilling operation and investigate the optimum polymer concentration that give the minimum pressure drop. a flow loop was designed for this purpose consist from 14 m long with transparent test section and differential pressure transmitter that allows to sense and measure the pressure losses along the test section. the results from the experimental work show that increasing in polymer concentration help to reduce the pressure drop in annulus and the optimum polymer concentration with the maximum drag reducing is 0.8 kg/m 3 . also increasing in flow rate and corresponding fluid velocity in the gap of the annulus helped to reduce the pressure losses due to fluid flow. keywords: hole cleaning, polymer, horizontal well, drag reducer received on 04/11/2018, accepted on 25/02/2019, published on 30/12/1029 https://doi.org/10.31699/ijcpe.2019.4.6 1introduction poor hole cleaning while drilling operations especially in high deviated well is the main reason for many unwanted issues encountered while drilling. for this purpose, the numerous researchers work on cutting transportation [1][2][3]. since force of gravity has acted against the transportation direction, it can cause the buildup of cuttings on the bottom of the wellbore. those deposits are usually called cuttings bed. sufficient sweep of drilled cuttings from hole and transport it to the surface is a main challenge in oil well drilling, for vertical well operation this issue was well studied since that any parameters can reduce the slip velocity of the cuttings can efficiently influence on the hole cleaning , but for the deviated well operation hole cleaning is still a big challenge [4].so proper strategy of hole cleaning is an important to get good drilling operations because insufficient hole cleaning may lead to many problems such as [5]: a) low rotation per minute(rpm). b) increase torque and drag force. c) increase risk of pipe stuck. d) difficulty in landing the casing and hole cementing. e) difficulty while logging. f) bit wearing, etc. the drilling fluid circulation rate is the most effective parameters on hole cleaning and that was proved by many previous studies. the problem with flow rate value is that the increasing in rate of circulation will cause a sharp increase in bottom hole pressure and that will lead to increasing the dynamic bottom hole pressure and may cause fracture to the rock. the solution should be offered the ability to transport more cuttings to the surface while keep the bottom hole pressure without big change. many ideas subsist in the industry as what an optimum concentration of drilling cuttings should be to keep ecd in safe margin and they find that cuttings concentration below 1 percent of volume is very safe and above that concentration has a significant effect on ecd [6]. al-yaari et.al (2009) [7] in their study focus on the evaluating of the pressure reading difference and the flow pattern features for various flow regimes and also determined the effect of the polymer on pressure drop in the region of phase inversion at higher mixture speed and a high pressure drop is happen in pipe lines. the polymer molecular weight and concentrations were investigated in this study. the results from the experimental work show that the increase in polymer concentration increases the drag reduce and that because of enhancing the formation of aggregates which play a crucial role in reducing pressure drop. al-wahaibi et.al (2013) [8] experimentally studied the performance of drag reducing polymers through two different pipes diameter in horizontal oil-water flows. the results of this study show that the polymer concentration of 2 ppm give a significant drag reduction and that increase as the polymer concentration increase also the drag reduction increase as superficial water velocity increase. https://doi.org/10.31699/ijcpe.2019.4.6 k. a. mohammed and a. a. al-haleem / iraqi journal of chemical and petroleum engineering 20,4 (2019) 35 40 63 2experimental setup and design 2.1. flow loop design a cuttings transportation flow loop was built to determine the effect of different parameters on hole cleaning. the cuttings transport flow loop consists of approximately 14 m (46 ft.) long with transparent glass test section of 3m (9.84 ft.) long with 4 inch (101.6 mm) id, the glass tubes (duran manufacturer) are made from high quality optical glass (borosilicate glass) with 100% transparency required for imaging and recording while test. the glass tubes (two tubes) are connected to each other by specially designed teflon joints that having an inner diameter equal to the pipes to ensuring a smooth path for the flow. the transparent test section changed with pvc tube for same diameter when the inclination angle less than 90°. the inner metal drill pipe with 2 inch (50.8 mm) od settled with eccentric position positive 0.5, it is fixed by metal structure designed to be not influenced on cuttings path. the inner pipe in this study designed to be stationary (no rpm) during the experiments to simulate the actual slide drilling conditions ( in long horizontal and extended reach wells sometimes it is not possible to rotate the drill pipe and depend on down hole motor rotation). the fluid feed line made from pvc with 4 inch id as long of 8 m and the main function is to transport the drilling fluid to test section and in position while it near the inlet of the test section the cuttings are injected to flow to pass as two phases(cuttings-drilling fluid) during the test section. the test section was attached with the feed line through movable joint in order to change the degree of test section inclination. all experiments were conducted under ambient temperature and atmospheric pressure conditions; a schematic diagram of the flow loop was shown in fig. 1. fig. 1. cuttings transport flow loop (schematic diagram) the drilling fluid is mixed in a mixing tank of 1 m 3 (1000 liters) where the liquid is supplied to feed line (in case of water-polymer drilling fluid there are two separate tanks, where the polymer is dissolved in water in first tank and then allowed to rest for 15 hour in 0.725 m 3 (725 liters) tank and then transported and diluted to desired concentration into suction tank). the agitator kept working for two hours before drilling mud have been pumped to feed line to prevent the separation and settling of the mud material. the test fluid is pumped and circulated through the system by a 3 h.p. centrifugal pump which provides a maximum capacity of 220 gpm (50 m 3 /hr.). the pump has been selected to be suitable in case of coarse solid particle dissolution pass through it. the pump outlet is connected to two lines, one is a bypass line and the other one is going to the flow meter,the bypass line is used to regulate the flow rate of the mud pump and also as a jetting tool when polymer has been mixed in mixing tank. the flow rate is measured by means of a volumetric flow meter of 21 m 3 /hr. maximum flow rate measuring range. the flow meter is already calibrated and has accuracy equal to 0.1%. during the experiment, the frictional pressure drop between two points in test section was measured. the first point is located 1 m (3.28 ft.) away from the annulus inlet and the second point is located 2.5 m (8.2 ft.) from the annulus outlet. the two points is selected in the middle of test section away from the annulus inlet/outlet to avoid the end effect and also to obtain data from the fully developed flow section. these two vents are connected to a differential pressure transmitter (schoppe and faeser gmbh inc.) by a brass lines filled with water, the connected lines are bled before each test to eliminate the contamination problem of the pressure vent, the device reading range is 0 – 25 millibar.a high speed digital camera is also used in this experiment to record the different phenomena that occur inside test section and the cuttings-fluid flow patterns. the drilling fluid (drag reducing fluid) was prepared by using carboxymethyl cellulose (cmc for short) as a commercially available polymer, and actual cuttings from field was used in this experiment. 2.2. experimental procedure all experiments were done under atmospheric pressure and ambient temperature with no rotating drill pipe eccentric at positive 0.5. before the start of each run the drilling mud was mixed and prepared and also the ph raised to 10 by adding specific amount of caustic soda (in case of water-polymer drilling mud the mixed procedure presents by wyatt et. al. was implemented). before run, the drilling fluid was agitated for 15+ minute and sample is taken to measure the fluid properties. k. a. mohammed and a. a. al-haleem / iraqi journal of chemical and petroleum engineering 20,4 (2019) 35 40 63 a brief description of the experimental work steps followed during the execution of the experiments is presented as follow: 1. prepare the drilling fluid (water or polymer) in the mud tank. 2. check the differential pressure transmitter lines for being full with water. 3. adjusted all other factors involves in this experiments:  cuttings types limestone and limestone-dolomite.  cuttings size two ranges (1.7 and 3.36 mm).  annular velocity two ranges (2.0558and 2.8781 m/sec.), these two ranges are selected as the minimum value is the lowest velocity that cleaning cuttings and permit the visually recognize to the flow pattern, and the maximum value have been choose as the maximum reading of flow meter available.  drilling fluid type (water , 0.8 kg/m 3 polymer and 1.8 kg/m 3 polymer) 4. start the pump and adjusted the liquid flow rate (66 and 92.5 gpm). 5. wait for flow pattern stabilization by checked in both visual observation and examining the differential pressure reading. 6. start recording data (flow rate and pressure drop reading). 7. inject the cuttings that simulated the desired rop. 8. start camera to record the cuttings transport mechanisms. 9. start record data (flow rate and pressure drop reading). 10. collect the outlet cutting from sieve screen, to calculate the cuttings recovered. 11. stop camera. 12. circulate with high flow rate to clean the annulus from remain cuttings after test. 13. repeat steps 3 to 13 with new cuttings density. 14. stop pump. 15. repeat steps 3 to 14 for new mud type. 3effects of polymer concentration on drag reducer drilling fluids drag reduction additives first utilized during the hydraulic fracturing operations to pump sand with lower horsepower [9].the drag reducer has a benefit in hole cleaning as it work to reduce the pressure loss during the circulation. the drag reducing percent for different polymer fluid compared with water can be calculated from the following equation eq.1 [10]: dr%= 100( ) (1) where: dr= drag reducing δp without drp pressure drop due to flow of water, millibar δp with drp=pressure drop due to flow of polymer, millibar. table 1 shows the results of the drag reducing and pressure drop for different polymer concentration against water. as shown from the fig. 2 the polymer concentration that gives the minimum frictional pressure drop remains the same for different flow rates, also the drag reduction percent increase as the flow rate increase for the same polymer concentration. in this study only two values of flow rates were involved and that show an increase in drag reduction (dr) with the increment of flow rate value but in previous study discover that the dr reaches its maximum value for a certain flow rate and after that any increase in flow rate will cause reduction in dr due to shear degradation of the polymer molecules and that makse the effectiveness of the drag reducing polymer reduces after that value of flow rate “several studies have suggested a direct relationship between changes in molecular weight distribution and drag reducing effectiveness for a variety of polymers. an alternative explanation for the polymer degradation is that some or all of the degradation is associated with a decrease in the amount of polymer aggregation or entanglements. a decrease in aggregation would be caused bymechanical stresses breaking up existing aggregates and preventingfurther aggregate formation in a shear flow” [11,12]. table 1. drag reduction percent for 90° hole inclination flow rate m 3 /hr. fluid type pressure losses m bar drag reduction % 15 water 12.5 15 0.8 kg/m 3 polymer 9.5 24 15 1.8 kg/m 3 polymer 10 20 21 water 20 21 0.8 kg/m 3 polymer 13 35 21 1.8 kg/m 3 polymer 14.5 27.5 fig. 2. polymer concentration versus drag reduction for different flow rates k. a. mohammed and a. a. al-haleem / iraqi journal of chemical and petroleum engineering 20,4 (2019) 35 40 63 4polymer concentration effect on delivered cuttings concentration as shown from the fig. 3 that the polymer concentration have a significant effect on the amount of cuttings transported, the increase in polymer concentration will increase the dr value until it reaches to maximum value of dr (at polymer concentration equal to 0.8 kg/m 3 were the drag reduction values are 24% and 35 % for flow rate 15 and 21 m 3 /hr, respectively as shown in fig. 2) and after that any increasing in polymer concentration have a contrary effect on dr, any increase in dr will cause most efficient cuttings transported. in other words, the increase in polymer concentration will increase the hole cleaning efficiency till it reaches the point of maximum dr and then any more polymer concentration added will affect negatively on the cuttings transport, which was also observed in previous study [13]. the improvement recorded by the drilling mud with cmc low viscosity polymer has been influenced by two main factors that influences on cuttings slipping velocity. in general, these two factors are the ability of the polymer to reduce the slipping velocity of the drilling cuttings due to its buoyancy in the drilling fluids and the effect on the reynolds number of the cuttings were it reduced and that will increase the drag coefficient of the particles, as a results of these two factors the hole cleaning will improved, and that also observed by other studies [14,15]. fig. 3. polymer concentration vs. cr% for 90° inclination 5cuttings density and size effect on delivered cuttings concentration cuttings density has a direct influence on the cuttings slip velocity and that influence dominated clearly in near vertical well angles but for the horizontal and near horizontal well the influence of the cuttings density has a direct influence on the gravity force and by means on the lifting/sliding force of the cuttings bed, and that clearly observed in fig. 4 and fig. 5. fig. 4. cuttings s.g. vs. cr% for 3.35 mm size with water and fr=15 m 3 /hr fig. 5. cuttings s.g. vs. cr% for 3.35 mm size with water and fr=21m 3 /hr the size of the drilled cuttings also has a big influence on the bed height and cuttings recovered percent since that large cuttings size have a tendency to form bed and roll along the low side of the well bore. the cuttings with large size at high angles (65° and more) tend to form stationary bed at the low side of the well, in that case and with absence of the pipe rotation only the high flow rate can disturbed the bed and achieve a homogeneous suspension, as shown in figure.6 and figure.7, also from these figures it can observed that the influence of the cuttings size is more simple compared with the density of the cuttings and that can be seen in figure.7 when the density of the cuttings increased the effect of the size being less. k. a. mohammed and a. a. al-haleem / iraqi journal of chemical and petroleum engineering 20,4 (2019) 35 40 63 fig. 6. cr% vs. cuttings size mm for limestone with 0.8 kg/m 3 polymer and fr=21 m 3 /hr fig. 7. cr% vs. cuttings size mm for limestone-dolomite with 0.8 kg/m 3 polymer and fr=21 m 3 /hr 6conclusions the results from the experimental work showed that: 1different cmc polymer concentration varied from 0.8 kg/m3 to 1.8 kg/m3 were used in these experiments. with polymer concentration of 0.8 kg/m3, it was obtained a minimum pressure drop and maximum drag reductions. 2the results showed that the optimum cmc polymer concentrations which gave maximum drag reductions and cuttings removal was 0.8 kg/m3and any further added of polymer will cause reduction in dr and that mean reduction in hole cleaning efficiency. the addition of the drag reductions agent to the drilling fluids will reduce the frictional pressure drop in the annulus and that effect will increase as the flow rate increase from 15 to 21 m 3 /hr. nomenclatures rpm= rotation per minute. id, od= inner and outer diameter, mm. h.p.= horse power. cmc= carboxymethyl cellulose. dr= drag reducing. δp without drp pressure drop due to flow of water, millibar. δp with drp=pressure drop due to flow of polymer, millibar. fr= flow rate, m 3 /hr. references [1] f. h. m. al-mahdawi and k. saad, “enhancement of drilling fluid properties using nanoparticles”, ijcpe, vol. 19, no. 2, pp. 21-26, jun. 2018. [2] a. assi, “potato starch for enhancing the properties of the drilling fluids”, ijcpe, vol. 19, no. 3, pp. 33-40, sep. 2018. [3] h. neamah and a. a.alrazzaq, “torque and drag forces problems in highly deviated oil well”, ijcpe, vol. 19, no. 3, pp. 19-31, sep. 2018. [4] j. li and s. walker, may 2001, “sensitivity analysis of hole cleaning parameters in directional wells” spe/icota coiled tubing roundtable, pp. 356–363. [5] xiao-le guo, wen-yin li and ji-lin liu,, 2017 “simulation on cuttings transport with drill pipe rotation in highly-inclined well section” university of science and technology, international conference on applied mechanics and mechanical automation. [6] j. mitchell, 2001, “trouble-free drilling”, pre-edition., vol. 1. woodlands, tx: drilbert engineering. [7] m. al-yaari, a. soleimani, b. abu-sharkh, u. almubaiyedh, a. al-sarkhi, 2009, “effect of drag reduction polymer on oil-water flow in a horizontal pipe”, international journal of multiphase flow,volume 35, issue 6, pages 516-524. [8] al-wahaibi, t., al-wahaibi, y., al-ajmi, a., yusuf, n., al-hashmi, a. r., olawale, a. s., & mohammed, i. a. 2013. “experimental investigation on the performance of drag reducing polymers through two pipe diameters in horizontal oil-water flows”, experimental thermal and fluid science, 50, 139146. [9] c. ercan and m. e. ozbayoglu, 2009, “phpa as a frictional pressure loss reducer and its pressure loss estimation” middle east drilling technology conference & exhibition. [10] n. yusuf, t. al-wahaibi, y. al-wahaibi, a. alajmi, a. al-hashmi, a. olawale, and i. mohammed, 2012, “experimental study on the effect of drag reducing polymer on flow patterns and drag reduction in a horizontal oil–water flow” international journal of heat and fluid flow, vol. 37, pp. 74–80 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/162 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/162 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/162 https://doi.org/10.31699/ijcpe.2018.3.4 https://doi.org/10.31699/ijcpe.2018.3.4 https://doi.org/10.31699/ijcpe.2018.3.4 https://doi.org/10.31699/ijcpe.2018.3.3 https://doi.org/10.31699/ijcpe.2018.3.3 https://doi.org/10.31699/ijcpe.2018.3.3 https://www.onepetro.org/journal-paper/spe-74710-pa https://www.onepetro.org/journal-paper/spe-74710-pa https://www.onepetro.org/journal-paper/spe-74710-pa http://www.dpi-proceedings.com/index.php/dtetr/article/view/13334 http://www.dpi-proceedings.com/index.php/dtetr/article/view/13334 http://www.dpi-proceedings.com/index.php/dtetr/article/view/13334 http://www.dpi-proceedings.com/index.php/dtetr/article/view/13334 http://www.dpi-proceedings.com/index.php/dtetr/article/view/13334 https://www.wellcontrol.com/content/pdf/marketing-material/wcs_trouble_free_drilling.pdf https://www.wellcontrol.com/content/pdf/marketing-material/wcs_trouble_free_drilling.pdf https://www.sciencedirect.com/science/article/abs/pii/s0301932209000354 https://www.sciencedirect.com/science/article/abs/pii/s0301932209000354 https://www.sciencedirect.com/science/article/abs/pii/s0301932209000354 https://www.sciencedirect.com/science/article/abs/pii/s0301932209000354 https://www.sciencedirect.com/science/article/abs/pii/s0301932209000354 https://www.sciencedirect.com/science/article/pii/s0894177713001350 https://www.sciencedirect.com/science/article/pii/s0894177713001350 https://www.sciencedirect.com/science/article/pii/s0894177713001350 https://www.sciencedirect.com/science/article/pii/s0894177713001350 https://www.sciencedirect.com/science/article/pii/s0894177713001350 https://www.sciencedirect.com/science/article/pii/s0894177713001350 https://www.sciencedirect.com/science/article/pii/s0894177713001350 https://www.onepetro.org/conference-paper/spe-125992-ms https://www.onepetro.org/conference-paper/spe-125992-ms https://www.onepetro.org/conference-paper/spe-125992-ms https://www.onepetro.org/conference-paper/spe-125992-ms https://www.sciencedirect.com/science/article/pii/s0142727x1200063x https://www.sciencedirect.com/science/article/pii/s0142727x1200063x https://www.sciencedirect.com/science/article/pii/s0142727x1200063x https://www.sciencedirect.com/science/article/pii/s0142727x1200063x https://www.sciencedirect.com/science/article/pii/s0142727x1200063x https://www.sciencedirect.com/science/article/pii/s0142727x1200063x k. a. mohammed and a. a. al-haleem / iraqi journal of chemical and petroleum engineering 20,4 (2019) 35 40 04 [11] n. b. wyatt, c. m. gunther, and m. w. liberator, 2011, “drag reduction effectiveness of dilute and entangled xanthan in turbulent pipe flow” journal of non-newtonian fluid mechanics, vol. 166, no. 1-2, pp. 25–31. [12] m. vlachogiannis, m.w. liberatore, a.j. mchugh, t.j. hanratty, 2003 “effectiveness of a drag reducing polymer: relation to molecular weight distribution and structuring”physics of fluids 15 (2003) 3786–3794. [13] payam allahvirdizadeh,2015, “a comparative study of cuttings transport performance of water versus polymer-based fluids in horizontal well drilling” m.s. thesis, school of applied and natural science, middle east technical university. [14] onuoha, ismail, a. piroozian, n.s. mamat, a.s. ismail, 2015, “improving the cuttings transpot performance of water-based mud through the use of polypropylene beads” malaysia. [15] r. clark and k. bickham, 1994, “a mechanistic model for cuttings transport” proceedings of spe annual technical conference and exhibition. االفقية كفاءة تنظيف البئر باستخدام الماء و البوليمر في االباردراسة مقارنة لبيان كرار احمد و اياد عبدالحليم كلية الهندسة-جامعة بغداد الخالصة كمقمل احتكاك (cmc)اليدف الرئيسي من ىذه الدراسة ىو التطبيق العممي لمعرفة تأثير البوليمر من نوع عمى فرق الضغط الحاصل في الفراغ الحمقي خالل عمميات الحفر. منظومة جريان صممت ليذا لغرض تتألف متر طول مع مقطع تجريبي شفاف و جياز لقياس فرق الضغط يسمح بتحسس و قياس الضغط المفقود 14من ت بأن الزيادة في تركيز البوليمر تساعد عمى خالل المقطع التجريبي. النتائج المستحصمة من التجربة العممية بين 0.8تخفيض فقدان الضغط الحاصل في الفراغ الحمقي و افضل تركيز لمبوليمر مع افضل تقميل لالحتكاك ىو متر مكعب, وكذلك زيادة دفق سائل الحفر و سرعة الجريان المصاحبة لو في الفراغ الحمقي يساعد عمى \كغم نتيجة جريان سائل الحفر.تقميل فقدان الضغط الحاصل الكممات الدالة: بوليمر, البئر االفقي https://www.sciencedirect.com/science/article/abs/pii/s0377025710002661 https://www.sciencedirect.com/science/article/abs/pii/s0377025710002661 https://www.sciencedirect.com/science/article/abs/pii/s0377025710002661 https://www.sciencedirect.com/science/article/abs/pii/s0377025710002661 https://www.sciencedirect.com/science/article/abs/pii/s0377025710002661 https://aip.scitation.org/doi/abs/10.1063/1.1624840 https://aip.scitation.org/doi/abs/10.1063/1.1624840 https://aip.scitation.org/doi/abs/10.1063/1.1624840 https://aip.scitation.org/doi/abs/10.1063/1.1624840 https://aip.scitation.org/doi/abs/10.1063/1.1624840 http://etd.lib.metu.edu.tr/upload/12619165/index.pdf http://etd.lib.metu.edu.tr/upload/12619165/index.pdf http://etd.lib.metu.edu.tr/upload/12619165/index.pdf http://etd.lib.metu.edu.tr/upload/12619165/index.pdf http://etd.lib.metu.edu.tr/upload/12619165/index.pdf http://journalarticle.ukm.my/8642/1/19_m.d.u._onuoha.pdf http://journalarticle.ukm.my/8642/1/19_m.d.u._onuoha.pdf http://journalarticle.ukm.my/8642/1/19_m.d.u._onuoha.pdf http://journalarticle.ukm.my/8642/1/19_m.d.u._onuoha.pdf https://www.onepetro.org/conference-paper/spe-28306-ms https://www.onepetro.org/conference-paper/spe-28306-ms https://www.onepetro.org/conference-paper/spe-28306-ms iraqi journal of chemical and petroleum engineering vol.17 no.1 (march 2016) 4760 issn: 1997-4884 kinetics and mass transfer study of oleic acid esterification over prepared nanoporous hy zeolite ammar s. abbas 1 , talib m. albayati 2 , ziad t. alismaeel 3 , & aidan m. doyle 4 1 department of chemical engineering, college of engineering, university of baghdad 2 department of chemical engineering, university of technology 3 department of biochemical engineering, al-khwarizmi college of engineering, university of baghdad 4 division of chemistry and environmental science, manchester metropolitan university abstract a mathematical model was proposed to study the microkinetics of esterification reaction of oleic acid with ethanol over prepared hy zeolite catalyst. the catalyst was prepared from iraqi kaolin source and its properties were characterized by different techniques. the esterification was done under different temperature (40 to 70˚c) with 6:1 for molar ratio of ethanol to oleic acid and 5 % catalyst loading. the microkinetics study was done over two period of time each period was examined individually to calculate the reaction rate constant and activation energy. the impact of the mass transfer resistance to the reactant was also investigated; two different studies have been accomplished to do this purpose. the effect of the external mass transfer resistance was studied by exploring different stirring speed (400 to 800 rpm). the results show that, the oleic acid conversion increase with increasing the stirring speed until reached 600 rpm, after this rpm the conversion doesn’t increase significantly, which mean that, the effect of external mass transfer resistance was eliminated. the activation energy for the first period is equal to 41.84 kj/mol while in the second period is equal to 52.03 kj/mol. the thiele modulus calculation results show that there is no effect of mass transfer on the reaction inside the catalyst pores. key words: biodiesel, microkinetics, nanoporous, hy zeolite, mass transfer, oleic acid, heterogeneous catalyst, thiele modulus introduction biodiesel can be defined as monoalkyl esters of long chain fatty acids derived from vegetable oils or animal fats and alcohol with or without a catalyst [1-5]. biodiesel can be produced by an efficient and commonly method called transesterification reaction from which vegetable oil reacted with suitable alcohol to produce biodiesel and glycerol, therefore this method called alcoholysis [6, 7]. methanol is widely used as alcohol reactant which is mainly produced by oxidation processes of methane, a natural gas component, hence a nonrenewable energy [8, 9]. ethyl alcohol iraqi journal of chemical and petroleum engineering university of baghdad college of engineering kinetics and mass transfer study of oleic acid esterification over prepared nanoporous hy zeolite 48 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net is also suitable to use in esterification or transesterification reactions to produce the biodiesel [4, 10-12]. oils and fats such as waste cooking oils, non-edible oils (jatropha oil, for example), and various animals fats are promising raw materials for biodiesel production. such materials are having large amount of free fatty acid (ffa) that causes undesired phenomena of the formation of soap as a by-product. therefore, before transesterification reaction, free fatty acid must converted to fatty acid methyl or ethyl ester by esterification reaction [13]. esterification reactions can be carried out by acid such as sulfuric acid or hydrochloric acid in case of using homogeneous acidic catalysts to produce alcoholic esters and water. in spite of acid homogenous catalysts does not make the problems of forming soap as when used homogeneous base catalysts, but another problems may arise likes formation of high quantities of by-products beside corrosion problems, therefore, the using of solid acid catalysts (heterogeneous catalysts) are always recommended to overcome these problems in esterification process [14]. the solid acid catalysts have many advantages besides overcoming the defects of homogeneous acid catalysts in that it's simply recovery of catalyst with a filtration, higher activity, selectivity, longer usage and compatible with environment, the reusability criterion of the heterogeneous catalysts make continuous mode i.e. fixed-bed very effective. such continuous process can reduce product separation and purification costs, make it economically viable to compete with commercial petroleum-based diesel fuel [15]. solid acid catalysts can carry out esterification reactions and transesterification reactions simultaneously [16, 17]. many types of solid acid catalysts, such as zeolites [11, 12, 18], amberlyst-15 [19], so4/zro2 [20] and tin compounds [21] have been tested in biodiesel synthesis. the kinetic mechanism for esterification reaction is complicated when heterogeneous catalysts are used. the rate determining step in carboxylic acid esterification can be any of the elementary reaction steps, including external mass transport in the bulk liquid, adsorption, desorption, and surface reactions. therefore, heterogeneous kinetic models based on langmuir-hinshelwood (lhhw) and eley-rideal (er) mechanism was applied for the esterification process [22]. kinetics of heterogeneously catalyzed transesterification follows lhhw model when using solid catalysts containing lewis acid/base sites [23], while er mechanism was followed by solid base catalysts [24]. a solid catalyst that leached substantially into the reaction media cannot be considered heterogeneous as the reaction mechanism of such catalysts followed kinetic mechanisms similar to that of homogeneous transesterification [10, 25]. in this present work, a first-order kinetics model for esterification reaction of oleic acid with ethanol catalyzed by nanoporous hy zeolite will be proposed based on langmuirhinshelwood model. the effect of external mass transfer resistance was investigated to select the optimum rpm that used for kinetic inspection. the overall reaction rate was assumed to follow a first-order expression with respect to oleic acid. the rate-limiting step will be also determined and the effective activation energy will be calculated based on the experimental data. finally, the effect of internal mass transfer resistance to the reactant will also be investigated based on thiele modulus calculations. ammar s. abbas, talib m. albayati, ziad t. alismaeel, & aidan m. doyle -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 49 experimental work catalyst preparation preparation of zeolite from iraqi kaolin the preparation of hy-kaolin was included two steps as conventional methods of preparation [26], the first step deals with the prepared of nay zeolite as an intermediate step and the next step related to convert nay to hy zeolite (hy-kaolin) using ion exchange technique. preparation of nay-kaolin zeolite iraqi kaolin clay was sieved to 75µ to ensure very fine powder and then mixed with 40 wt % sodium hydroxide solutions, using 1 kaolin /1.5 naoh by weight, then, the mixture entered furnace at 1123 k for 3 hours to obtain fused kaolin. the fused kaolin was milled to convert it in powder form. 50 g of the prepared kaolin and 63 g of sodium silicate were dispersed in 500 ml of deionized water under constant stirring at 323 k for 1 h by electrical magnetic stirrer, heat (stuart (cb302) / usa). the slurry with ph approximately 13.3 was transferred to teflon bottle and entered an oven for ageing at 323 k for 24 h, under static conditions. the slurry was crystallized at 373 k for 48 h, after that, the crystalline slurry was filtered using buchner funnel with the aid of a vacuum pump and washed with deionized water until the ph arriving to 11.7. the crystalline mass in filter paper was entered again to the oven for drying at 373 k for 16 h; finally, in order to obtain a pure nay zeolite, the dried powder was calcined at 773 k for 1 h. preparation of hy-kaolin zeolite one hundred grams of prepared nay zeolite was mixed with 600 ml of saturated aqueous solution of 1 m ammonium nitrate at 353 k for 4 h, placing in the 3 necks flask (1000 ml), which fitted with reflex condenser. the mixture was filtrated, washed with deionized water and finally dried at 373 k for 6 h, the product from this step called nh4y zeolite. 40 g of the prepare nh4y zeolite was mixed with 800 ml of 0.5 n oxalic acid at room temperature for 8 h. the slurry was filtered, washed with deionized water and dried at 373 k; finally the dried zeolite was calcined at 823 k for 5 h. catalysts characterizations the crystallinity of the powder patterns for prepared hy zeolite was investigated using x-ray diffraction (xrd) using diffraction angle 2θ (deg) between 4˚ and 50˚ with a 2θ step size of 0.026 and a step time of 50 sec with cu kα radiation (λ = 1.5406 a˚), the x-ray tube operated at 40 kv and 30 ma using fixed 1/4˚ anti-scatter slit. nitrogen adsorption / desorption measurements were conducted using a micromeritics asap 2020, pore analysis by n2 physisorption at -196 ˚c. the sample were degassing for 12 h at 350˚c under vacuum pressure (less than 10 -5 mbar) prior to analysis. bet-surface areas of the samples were calculated using the brunauer– emmett–teller (bet) method in relative pressure range 0.05–0.35. the total pore volume is specified from the adsorption branch of the n2 isotherm as the amount of liquid nitrogen adsorbed at p/p0 = 0.995. mesoporous mean diameters for prepared hy was calculated from the nitrogen sorption data using bet analysis (4 v/a). the hydrodynamic diameter zeolites was determined by dynamic light scattering (dls) technique using zeta sizer (malvern instrument), micropours structure was determined by scanning electron microscopy (sem). the x-ray fluorescent (xrf) was applied to catalyst for chemical elemental analysis. kinetics and mass transfer study of oleic acid esterification over prepared nanoporous hy zeolite 50 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net experimental setup the esterification reaction of oleic acid in batch reactor was carried out in a laboratory scale reactor as shown in figure 1. the apparatus used for the experiment consists of 500 ml three neck flat bottom glass flask and electrical heater with magnetic stirrer arrangement to achieve a perfect contact among the reactants. one side neck of the reactor is plugged with air tight rubber stopper which holds the thermometer used to measure the reaction temperature. the other side neck is used to draw the sample oil and alcohol catalyst mixture. the water cooled condenser was inserted through the main neck of the reactor to recover the escaping ethanol which has a boiling point of 78 ˚c and vaporizes at the elevated temperature during the reaction. the condenser also helps in maintaining atmospheric pressure inside the reactor; water path was used in order to keep the temperature at the desired level fig. 1, schematic diagram of the batch reactor the desired amount of catalyst (hy zeolite) before each experimental was dried at 130°c up to 2 h to eliminate any possible amount of water. at the beginning, the reactor was kept in water bath and loaded with 50 ml (44.75 g) of oleic acid which was mixed with 6:1 ethanol to oil, preheated to desired temperature (40, 50, 60 or 70˚c) and then 5 wt. % prepared hy zeolite was added to the mixture. analytical method the mixtures of reactants which consist from the reactants and products were analyzed after each period of time (15 minutes), approximately 5 ml from the reaction mixture was withdrawn and centrifuged for 10 min to improve the separation of the phases and then certain amount from the top layer of product was taken and then added 2 drops of phenolphthalein as indicator and titrate with 0.1 molarity of koh in order to evaluate the acid value (av) as shown in the following equation; (karnasuta et al.,2007) … (1) from the acid value, the conversion of the oleic acid can be calculated for each amount of the catalyst as shown in the equation (2); … (2) where: avto (acid value of the reaction product at time 0) avt (acid value of the reaction product at time t) kinetic and mass transfer of esterification of oleic acid kinetic obtained from laboratory unit are usually play an important role in modeling and scale up designs for new biodiesel production units. differential method of analysis obtained data has been used to find ammar s. abbas, talib m. albayati, ziad t. alismaeel, & aidan m. doyle -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 51 suitable kinetic model for oleic acid esterification. assumptions for the present kinetic model in the present work, we focus on the kinetics model of reaction catalyzed by solid hy-kaolin, for single step. the stoichiometric equation of this reaction could be presented in equation (3): ↔ … (3) where oa is oleic acid (simulated free fatty acid in sunflower oil), e is ethanol, p is fatty acid ethyl esters (faee) and w is water. generally, the heterogeneouslycatalyzed esterification is a very complicated reaction involving a liquid-liquid-solid three-phase system where reactions occur on the surface of the solid catalyst. therefore, the chemical reaction rate on the catalyst surface, the external and internal mass transfer rate of reactant and product molecules, the absorption rate of reactant molecules on active sites of the catalyst, and the desorption rate of products could impact the overall rate. one or more of these rates may be the limiting rate. thus, the kinetics study of this liquid-liquid-solid system reaction in this present work will include not only developing the overall reaction rate expression but also identifying the rate-limiting step; some assumptions were made for developing the kinetics model: 1the external mass transfer of ethanol and oleic through the bulk phase to the catalyst surface and the internal diffusion rate of ethanol toward active sites do not limit the overall reaction rate i.e. the mixing of the reaction system is perfect and small particle size. 2ethanol and oleic acid molecules are chemisorbed on active sites, and the adsorption follows the first-order langmuir adsorption isotherm. since an excess amount of ethanol is used and the adsorption of ethanol on hy-kaolin zeolite is quick, the fraction of surface covered by ethanol is assumed to be constant. 3esterification reaction occurs between neighboring chemisorbed ethanol molecules oleic acid molecules. 4the overall esterification reaction on the catalyst surface follows pseudo-first order kinetics with respect to oleic acid and the reverse reaction can be neglected for the initial period of time before reaching the equilibrium reaction. 5no temperature gradient exists through the catalyst pore channel due to the small reaction heat and nano sized catalyst particles. 6the adsorption-desorption equilibrium of reaction products, faee (biodiesel) and water, is reached quickly and do not affect the overall rate. mathematical kinetics model based on the quasi-steady state assumption, the amount of adsorption of oleic acid (oa) molecules is equal to the sum of the amount of desorption and the amount of oleic acid consumed by chemical reaction on the surface. according to assumption (2), (3), and (4) the reaction rate is described as: … (4) where coa is the oleic acid concentration in the bulk liquid phase, ks is the chemical reaction constant on the catalyst surface, and θm is the occupied fraction of active sites by kinetics and mass transfer study of oleic acid esterification over prepared nanoporous hy zeolite 52 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net ethanol, coa,s is the concentration of oleic acid on the catalyst surface. according to the proposed reaction mechanism, the adsorption of oa is the rate-limiting step. then the net rate of oa adsorption-desorption is equal to the reaction rate on the catalyst surface: ( ) … (5) where rads-des is the net rate of oa adsorption-desorption, kads and kdes are adsorption and desorption rate constants, respectively, ∑θ is the total fraction covered by all species in the liquid mixture, rearrange eq. (5) to get the non measurable coa,s in terms of measurable coa: ( ) … (6) substitution of eq. (6) into eq. (4) results in: ( ) ( ) … (7) assuming; ( ) ( ) … (8) eq. (7) becomes: … (9) where keff is the effective rate constant reflecting both the chemical reaction and adsorption-desorption resistance on the surface. in a batch reactor, coa can be expressed in terms of the conversion of oleic acid xoa: ( ) … (10) where, coai is the initial concentration of oa. then eq. (9) becomes: ( ) … (11) the integration of eq. (11) between 0 and any time versus zero conversion and conversion, gives: ( ) … (12) result and discussion characterization of synthesized catalysts the crystallinity of the prepared hy zeolite was investigated by using xrd technique as shown in figure 2. from figure 2, the diffraction pattern of the prepared hy zeolite is approximately comparable with the standard faujasite zeolite (fau) type y according to the commission of the international zeolite association (iza) [27], since the highest peak at intercept (1, 1, 1) of the standard is 6.33 [28], which is nearly to the highest peak of the prepared zeolite which was equal to 6.34. the bet surface of the prepared hy zeolite was 389.55 m 2 /g while the pore volume and pore size of the prepared hy zeolite were equal to 0.853 cm 3 / g and 12.341 nm, respectively. the average particle size of the prepared hy zeolite was equal to 1435 nm according to dynamic light scattering (dls) technique. the chemical composition for the prepared catalysts was analyzed using x-ray fluoresce (xrf), as shown in table 1. the molar ratio (si/al) for the prepared hy zeolite was equal to 3.1; these results were in a good agreement with the results that obtained abbas and abbas [11, 12]. ammar s. abbas, talib m. albayati, ziad t. alismaeel, & aidan m. doyle -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 53 the surface structure (morphology) and also general view of the particle size distribution of the prepared and commercial hy zeolite can be explored by using scanning electron microscopy (sem) image, therefore, figure 3 represents the images of prepared hy zeolite at magnification of 1000 degree. the particle shape of the prepared hy zeolite as spherical particle and the increase in particle volume due to the large amount of the impurities that made particles had the agglomeration tendency as shown in figure 3. fig. 2, xrd patterns for the prepared hy zeolite table 1, the chemical composition of the of prepared hy zeolite oxides, wt. % al2o3 sio2 fe2o3 na2o mgo k2o cao p2o5 l.o.i hy zeolite 15.92 58.11 3.191 5.147 1.222 0.067 4.112 0.6448 11.587 l.o.i …loss on ignition fig. 3, scanning electron microscopy for prepared hy zeolite kinetics and mass transfer study of oleic acid esterification over prepared nanoporous hy zeolite 54 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net effect of the external mass transfer resistance on esterification reaction in order to study the effect of external mass transfer resistance to the oleic acid, different stirring speed (i.e. different rpm) were utilized for this purpose, figure 4 shown the relationship between oleic acid conversion with rpm at different temperature 40, 50, 60 and 70 ˚c with 6:1 molar ratio of ethanol to oleic and 5 wt. % of prepared hy zeolite loading with respect to oleic acid for one hour. fig. 4, the effect of the stirring speed on the esterification reaction of oleic acid the oleic conversion increase with increasing temperature and also the conversion increases with increasing stirring speeds until reach to 600 rpm, over these speeds (700 and 800 rpm), there is no significant increase in oleic acid conversion, so that, it can be considered the optimum stirring speed of the reactant is equal to 600 rpm by which the external mass transfer resistance can be neglected, this value of rpm agreed with many researchers outcomes [29, 30]. effect of reaction temperature on oleic acid conversion the reaction temperature is key factor for the kinetics of reactions because reaction rates are the temperature-dependent functions according arrhenius’s law. esterification of oleic acid with ethanol takes place in the liquid phase, hence the reaction temperature should not be above the boiling point of ethanol (the boiling point of ethanol is 78 ˚c at atmospheric pressure). figure 5 shows the oleic acid conversion with time at different temperatures: 40, 50, 60 and 70˚c for two hours, using 6:1 ethanol/oil molar ratios and 5wt. % of prepared hy zeolite with respect to oleic acid, these two values were selected as an optimum conditions since many researchers suggested these values [11, 14]. fig. 5, effect of reaction temperature on oleic acid conversion the conversion of oleic acid increase with increasing temperature, for instance, the conversion of oleic acid at 40˚c is about 41% after 90 minutes, while the conversion of oleic acid at 70˚c is about 84% at same time, and these results are expected since the increase in temperature leads to ammar s. abbas, talib m. albayati, ziad t. alismaeel, & aidan m. doyle -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 55 increase in molecular activity (i.e. more molecules have energy to overcome the energy barrier of the reaction and react easily [31, 32]. another reason may arises here, when temperature increase the viscosity of the reactants decrease, that’s means, the diffusion of the molecule is increased through the pores of the catalyst and as a results the reaction would be taken place rapidly at the active site of the catalyst for the first 45 minutes for all range of temperatures as shown in figure 5, after that, the conversion increase slightly until reach 90 minutes, finally, after 90 minutes, the conversion of oleic acid decreases due to deactivation of the hy-shale zeolite, and this deactivation attributed to clumping of water molecules inside the pores of the catalyst according to the hydrophilic property of the zeolite, consequently, the reverse reaction is increased and the conversion is decreased [33]. the maximum conversion at 70˚c was achieved after 90 minutes (i.e. the reaction reaches the equilibrium), while the maximum conversion at 40˚c was achieved after 120 minutes, it can be explained as the same reason above, since the reaction was very rapid at 70˚c, the catalyst deactivate early, while at 40˚c, the reaction was very slow that delay the deactivation of catalyst. effective rate constants and effective active energies effective rate constant (keff) can be obtained from the slop of plotting [–ln (1xoa)] versus time (t) at different temperatures according to the equation (12). figures 6 represent the oleic acid conversion for the period 0 to 45 min while this equation is not applicable for the period 45 to 90 min, therefore, using [xoa/1-xoa] instead of [–ln (1 xoa)] versus time which represent the second order with respect to oleic acid as shown in figure 7, with using the optimum conditions (5 wt % catalyst loading with respect to oleic acid, 6:1 ethanol/oil molar ratio and 600 rpm). the obtained effective reaction constants are listed in table 2. fig.6, reaction time (t) versus –ln (1xoa) plot for prepared hy zeolite in 045 min. fig. 7, reaction time versus xoa/1-xoa plot for prepared hy zeolite in 45-90 min. kinetics and mass transfer study of oleic acid esterification over prepared nanoporous hy zeolite 56 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net table 2, effective reaction constants for prepared hy zeolite temperature keff (min -1 ) 0 to 45 min 45 to 75 min 40 ˚ c 0.009 0.003 50 ˚ c 0.013 0.005 60 ˚ c 0.024 0.008 70 ˚ c 0.035 0.018 the activation energy can be evaluated from the reaction rate constant according to the arrhenius’s equation (eq. 13) [31, 32]. … (13) where: a0: is pre-exponential factor ea: is the activation energy of the reaction. the activation energy and preexponential factor can be calculated by converting arrhenius’s equation to linear form for a particular range of temperatures, therefore, by taking ln (natural log) to the equation 13 leading to: … (14) for various temperatures (t) and various reaction rate constant (keff) data as shown in table 3, a plot of ln k versus 1/t yields a straight line and the slop of the line is –ea/r. figure 8 show the plots of ln keff versus 1/t for prepared hy zeolite in 0-45min and 45-90 min respectively. the preexponential factors and effective activation energies obtained from equation 14 are listed in table 4. the effective activation energies in 0-45 min and 45-90 min are 41.84 kj/mol and 52.03 kj/mol, respectively, the chemical reaction step seems more temperature-sensitive than oleic acidadsorption step, since the activation energy in the second period is larger than the first period; the value of activation energy shows a good agreement with the value of activation energy obtaining from [34]. table 3, values of 1/t versus lnk for different time (0 to 45 and 45 to 90 min) temperature 0 45 min 45 – 90 min t (c ) t (k) 1/t k ln k k ln k 40 313.15 0.003193 0.009 -4.71053 0.003 -5.809143 50 323.15 0.003095 0.012 -4.42285 0.005 -5.2983174 60 333.15 0.003002 0.024 -3.7297 0.008 -4.8283137 70 343.15 0.002914 0.035 -3.35241 0.018 -4.0173835 fig. 8, plot ln keff versus 1/t for hykaolin table 4, effective activation energies, pre-exponential factors for different times time (min) ea (kj/mol) a0 (min -1 ) 0-45 41.84 82454.34 45-90 52.03 1329083.28 ammar s. abbas, talib m. albayati, ziad t. alismaeel, & aidan m. doyle -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 57 effect of internal mass transfer the esterification of oleic acid with ethanol catalyzed by solid acid contained three phases: liquids oil, ethanol phases and solid catalyst. consequently interphase mass transfer is playing a crucial role in the reaction rate so that, the intraparticle diffusion might be the limiting step for a number of reactions, especially when the reactions taken place over microporous catalysts [35, 36]. thiele modulus (mt) is the dimensionless parameter widely used to estimate quantitatively the effect internal mass transfer on the reaction rate [32]: √ ( ) … (15) and, … (16) where: n: order of the reaction l: characteristic length of the catalyst particles (cm) = , for sphere keff: pseudo first order effective rate constant for the reaction (s -1 ) deff: effective diffusivity coefficient of the limiting reactant into the catalysts pores (cm 2 .s -1 ) dab: molecular diffusion coefficient of the limiting reactant (cm 2 .s -1 ). 𝝐p: porosity of the catalyst particles 𝝉p: tortuosity of the catalyst pores the prepared hy zeolite catalyst can be assumed spherical particles as seen in sem technique (i.e. equation 19 is applicable) with the diameter of 1.435µm as evaluated from the dls technique. for different materials, 𝝐p are usually in the range of 0.3 – 0.8, and the 𝝉p from 1.4–12, (veljkovic et al., 2009). the value of the tortuosity (𝝉p) that chosen is equal to 4, since many researchers in the literature chooses this value for zeolite type y [36, 38]. the porosity of the catalyst (𝝐p) can be defined as the void fraction using equation (17) [31]. ( ) ( ) … (17) the bulk density of the hy-kaolin was experimentally calculated and it was equal to 0.472 g/cm 3 and also the pore volume was evaluated by pjh method and it was equal to 0.853 cm 3 /g, after substitution these values in equation (17), the value of the hykaolin porosity was equal to 0.403 the molecular diffusion coefficient of the oleic acid in ethanol (dab) can be calculated by using wilke-chang estimation method as shown in the relation [39]; ( ) … (18) where the subscript a= oleic acid & b= ethanol d˚ab = mutual diffusion coefficient of solute a in solvent b, cm 2 /s mb = molecular weight of solvent b, g/mol t = temperature, k ηb = viscosity of solvent b, cp va = molar volume of solute a at its normal boiling temperature, cm 3 /mol φ = association factor of solvent b, dimensionless wilke and chang [39] recommend that φ be chosen as 2.6 if the solvent is water, 1.9 if it is methanol, 1.5 it is ethanol, and 1.0 if it is unassociated. the molar volume (va) of the solute (oleic acid) can be calculated in terms of critical volume (vc) by using tyn and calus method as shown in the following equation; kinetics and mass transfer study of oleic acid esterification over prepared nanoporous hy zeolite 58 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net … (19) the value critical volume (vc) of oleic acid is 1152 cm 3 /mol [40], so that the value of molar volume (va) of oleic acid is equal to 460.52 cm 3 /mol. table (5), shows all values of molecular diffusion coefficient (dab) and also effective diffusion coefficient (deff) in cm 2 /s at different temperatures. the calculated thiele modulus values at different reaction temperature are listed in table (6). the calculated effective diffusivity coefficients values range from 6.162 x 10 -11 to 1.101 x 10 -10 form 40 to 70 ˚c and these values are in agreement with bobok et al. [38]. the values of thiele modulus (mt) are less than 0.4, so this indication that the effect of internal mass transfer on the overall reaction rate can be neglected and these results could be attributed to the small particle size that made pore diffusion resistance very small. finally, these results confirm the assumption (1). table 5, diffusivity coefficient calculation for prepared hy zeolite temp. (t) viscosity of ethanol ( ) 313 0.794 6.11565 e-06 6.16151 e-07 323 0.670 7.47905 e-06 7.53514 e-07 333 0.570 9.06333 e-06 9.13131 e-07 343 0.487 1.09266 e-05 1.10085 e-06 table 6, thiele modulus for prepared hy zeolite temp. diffusion coefficient (deff. , m 2 /s) 0 – 45 min 45 – 90 min √ keff keff 40˚c 6.16151e-11 0.009 0.002891 0.003 0.002043917 50˚c 7.53514e-11 0.013 0.003141 0.005 0.002386084 60˚c 9.13131e-11 0.024 0.003877 0.008 0.002741731 70˚c 1.10085e-10 0.035 0.004265 0.018 0.003745572 acknowledgments the authors are grateful to iraqi ministry of higher education and scientific research for financial support to carry out this work at the division of chemistry and environmental science at manchester metropolitan university, uk, as a part of the requirements for the degree of doctor of philosophy in chemical engineering at baghdad university. reference 1kafuku g, mbarawa m., “biodiesel production from croton megalocarpus oil and its process optimization”, fuel; 89: 2556–60, 2010 2janaun j, ellis n., “perspectives on biodiesel as a sustainable fuel”, renew sustain energy rev., vol. 14, no.4, pp.1312–1320, 2010. 3cherng-yuan l, jung-chi l., “oxidative stability produced from the crude fish oil from the waste parts of marine fish”, j. food agri. environ. 8(2):992-995, 2010. 4abbas a. s. and othman t. s., “production and evaluation of biodiesel from sheep fats waste”, iraqi journal of chemical and petroleum engineering , vol. 13, no. 1, pp. 11–18, 2012. 5kapilan n,, ashok b., reddy r., “technical aspects of biodiesel and its ammar s. abbas, talib m. albayati, ziad t. alismaeel, & aidan m. doyle -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 59 oxidation stability”, int. j. chem. tech. res.1(2):278-282, 2009. 6kouzu, m., hidaka, j.s., “transesterification of vegetable oil into biodiesel catalyzed by cao: a review”, fuel 93, 1–12, 2012. 7demirbas, a.and karslioglu, s., “biodiesel production facilities from vegetable oils and animal fats”, energy sources part a 29, 133–141, 2007. 8sharma, y.c., singh, b., upadhyay, s.n., “advancements in development and characterization of biodiesel: a review”, fuel 87, 2355–2373, 2008. 9fukuda, h., kondo, a., noda, h., “biodiesel fuel production by transesterification of oils”, j. biosci. bioeng. 92, 405–416, 2001. 10abbas, a. s. and abbas, s. m., “kinetic study and simulation of oleic acid esterification in different types of reactors”, iraqi journal of chemical and petroleum engineering, vol. 14, no. 2, pp. 13–20, 2013. 11abbas, a. s. and abbas, r. n., “kinetic study and simulation of oleic acid esterification over prepared nay zeolite catalyst,”, iraqi journal of chemical and petroleum engineering, vol. 14, no. 4, pp. 35–43, 2013. 12abbas, a. s. and abbas, r. n., “preparation and characterization of nay zeolite for biodiesel production”, iraqi j. chem. pet. eng., vol. 16, no. 2, pp. 19–29, 2015. 13han, m., w. yi, q. wu, y. liu, y. hong and d. wang, “preparation of biodiesel from waste oils catalyzed by a brønsted acidic ionic liquid”, bioresource technology, 100(7): 2308-2310, 2009. 14zhang, y., m.a. dube, d.d. mclean and m. kates, “biodiesel production from waste cooking oil: 1. process design and technological assessment”, bioresource technology, 89(1): 1-16, 2003. 15feng guo and zhen fang, “biodiesel production with solid catalysts”, biodiesel feedstocks and processing technologies, dr. margarita stoytcheva (ed.), isbn: 978-953-307713-0, 2011. 16mcneff c.v., mcneff l.c., nowlan yan b., d. t., rasmussen m., gyberg a. e., krohn b. j., fedie r.l., hoye t.r., “a continuous catalytic system for biodiesel production”, applied catalysis a: general, 343, pp. 39–48., 2008. 17yan s., salley s.o., ng k.y. s., “simultaneous transesterification and esterification of unrefined or waste oils over zno-la2o3 catalysts”, applied catalysis a: general, 353, 203–212, 2009. 18ramos mj. , casas a., rodriguez l. , romero r. ,perez a., “transesterification of sunflower oil over zeolites using different metal loading: a case of leaching and agglomeration studies”, applcatala: gen; 346: pp.79–85, 2008. 19chavan s.p., subbarao y.t., dantale s.w., sivappa r., “transesterification of ketoesters using amberlyst-15”, synth commun, 31:pp.289-294, 2001. 20fu b.s., gao l., niu l., wei r., and xiao g., “biodiesel from waste cooking oil via heterogeneous superacid catalyst so4/zro2“, energy & fuels 23, 569–572, 2009. 21einloft s., magalhães t. o., donato a., dullius j., and ligabue r., “biodiesel from rice bran oil: transesterification by tin compounds”, energy & fuels, 22, pp. 671–674, 2008. 22valentine chinaka eze, “the use of mesoscale oscillatory baffled reactors for rapid screening of heterogeneously catalyzed biodiesel production reactions”, thesis, school of chemical engineering and advanced materials, newcastle university, 2014. 23xiao, y., gao, l., xiao, g. and lv, j., “kinetics of the transesterification reaction catalyzed by solid base in a fixed-bed reactor”, energy & fuels, 24, (11), pp. 5829-5833, 2010. kinetics and mass transfer study of oleic acid esterification over prepared nanoporous hy zeolite 60 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net 24dossin t. f., reyniers m.f., marin g.b., “kinetics of heterogeneously mgo-catalyzed transesterification”, applied catalysis b: environmental, 61, 35–45, 2006. 25di serio, m., dimiccoli, m., cammarota, f., nastasi, m., santacesaria, e., “synthesis of biodiesel via homogeneous lewis acid catalyst”, journal of molecular catalysis a, chemical, vol.239, pp.111-115, 2005. 26mohammed abdul halim a., shakir, i. k. and esgair k. k., “the use of prepared zeolite y from iraqi kaolin for fluid catalytic cracking of vacuum gas oil”, journal of engineering, volume 19, number 10, pp. 1256-1270, 2013. 27parise j. b., d. r. corbin, l. abrams and d. e. cox, acta. cryst. c40 1493–1497, 1984. 28treacy m.m.j. and higgins j.b., “collection of simulated xrd powder patterns for zeolites”, fourth edition amsterdam: elsevier, 2001. 29lina zhao, “novel solid base catalysts for the production of biodiesel from lipids”, thesis, university of kansas, school of engineering, 2010. 30rajiv arora, vinay kapoor, and amrit pal toor, “esterification of free fatty acids in waste oil using a carbon-based solid acid catalyst”, 2 nd international conference on emerging trends in engineering and technology (icetet'2014), london (uk), may 30-31, 2014. 31hill, c. g. jr., “an introduction to chemical engineering kinetics and reactor design”, john willy and sons, 1977. 32levenspiel o., “chemical reaction engineering”, 3 rd edition, john wiley & sons, 1999. 33flanigen, e. m., broach, r. w. and steph, “zeolites in industrial separation and catalysis”, edited by santi kulprathipanja, wiley-vch verlag gmbh and co. kgaa, weinheim, 2010. 34shakoor, z. m., sukkar k. a. and baqer m. s., “reaction kinetics of acetic acid and n-butanol esterification catalyzed by dowex 50 catalyst”, eng. & tech. journal ,vol.29 , no.10 , pp. 2060-2072, 2011. 35colen g.c.m., vanduijn g. and vanoosten h.j., “effect of pore diffusion on the triacylglycerol distribution of partially hydrogenated trioleoylglycerol”, applied catalysis,43, pp. 339-350, 1988. 36ramirez e., larrayoz m. a., and recasens f., “intraparticle diffusion mechanisms in sc sunflower oil hydrogenation on pd”, aiche j., 52(4), pp.1539-1553, 2006. 37satterfield, c. n., “mass transfer in heterogeneous catalysis”, colonial press incorporation, clinton, massachusetts, 1970. 38bobok d., ondrejkova m., and e. kossaczky, “diffusion coefficients of n-heptane in a particle of molecular sieve nay”, chem. papers 43 (3) pp. 345-361, 1989. 39robert c., john m. and bruce e. poling, “the properties of the gases and liquid”, 4 th addition, mcgrawhill, inc., 1987. 40nemestóthy nándor, lászló gubicza, erika fehér and katalin bélafi-bakó “a kinetic model on enzymatic esterification of i-amyl alcohol and oleic acid by candida antarctica lipase b”, biotechnological utilization of fuel oil, food technol. biotechnol. 46 (1) pp. 44–50, 2008. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol. 24 no.2 (june 2023) 81 – 87 eissn: 2618-0707, pissn: 1997-4884 *corresponding author: name: marwa hussein mohammed ali, email: marwa.ali1607m@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. isotherms and kinetics study for adsorption of nitrogen from air using zeolite li-lsx to produce medical oxygen marwa hussein mohammed ali a, *, raghad f. almilly a, and riyadh kamil abid b a chemical engineering department, college of engineering, university of baghdad, baghdad, iraq b petroleum and petrochemical research center, ministry of science and technology (most), iraq abstract this research investigates the adsorption isotherm and adsorption kinetics of nitrogen from air using packed bed of li-lsx zeolite to get medical oxygen. experiments were carried out to estimate the produced oxygen purity under different operating conditions: input pressure of 0.5 – 2.5 bar, feed flow rate of air of 2 – 10 l.min-1 and packing height of 9-16 cm. the adsorption isotherm was studied at the best conditions of input pressure of 2.5 bar, the height of packing 16 cm, and flow rate 6 lmin-1 at ambient temperature, at these conditions the highest purity of oxygen by this system 73.15 vol % of outlet gas was produced. langmuir isotherm was the best models representing the experimental data., and the model parameters were the maximum monolayer coverage (qm) 200 mg. g-1 and kl 0.00234 l.mg -1. also, from the freundlich isotherm model, the sorption intensity (n) indicated favorable sorption of 1.435. the average free energy estimated from the drk isotherm model was 0.02 kj.mol-1, which proved the adsorption process to follow physical nature. the results got from experiments showed a coincidence to the pseudo-first-order kinetic model. keywords: zeolite li-lsx, medical oxygen, adsorption isotherm, adsorption kinetic, nitrogen adsorption. received on 04/08/2022, received in revised form on 13/10/2022, accepted on 15/10/2022, published on 30/06/2023 https://doi.org/10.31699/ijcpe.2023.2.9 1introduction 1.1. pressure – vacuum swing adsorption process covid-19 outbreak stimulates researchers to investigate another source of medical oxygen as an alternative to the conventional method of the cryogenic process, which consumes a large amount of energy. that is because of the huge increase in the need for portable medical oxygen concentrators (mocs) because of pulmonary failure caused by covid-19 as well as chronic bronchitis, pneumonia and chronic obstructive pulmonary disease (copd) to avoid problems caused by hypoxemia [1-3]. adsorption, membranes, and cryogenic separation are the three main ways to separate the different parts of air [1]. adsorption is the most promising method for its simplicity, appropriateness in terms of moderate conditions, and low energy consumption, moreover, the separation method by adsorption is used to make very pure oxygen [1]. a lot of equipment that produce medical oxygen are made to get pure oxygen [2]. different adsorption methods were experimented with to adsorb nitrogen gas selectively from air to produce pure oxygen gas. pressure swing as well as vacuum swing, or pressure/vacuum swing adsorption processes, which is symbolized by pvsa, were tried using n2-selective adsorbents [3]. also, temperature swing adsorption (tsa) process was experienced [6]. it was demonstrated that psa was more feasible than tsa process [2]. that is because psa process cycle has a time of between one to several seconds, unlike the tsa process cycle which has a time extends to hours [6]. pvsa process is the common way to separate gases since the adsorption step is carried out at above atmospheric pressure and the step of regeneration is conducted under a vacuum pressure [7]. there are three points that make pvsa excel than psa. the first is that the o2/n2 recovery rate and purity of the pvsa process is better than those of the psa process [3]. the gas exits from heavy-reflux and light-reflux streams is used and that is why pvsa yield is more than psa. this leads to an increase in both pvsa process productivity and capacity of adsorbents relative to those of psa. the second point is in terms of total energy use. psa process uses more energy than pvsa process. this is because pvsa includes vacuum pump which uses less energy in comparison with a conventional pump. the third point is that the mass transfer zones for the light and heavy components often get in a common way in a formal dualreflux psa process with has an intermediate feed. this problem can be solved with these newly integrated pvsa processes. zeolites are likely to be used to separate air into its components because n2 gas molecules' dipole and quadrupole moments interact with extra cations of the zeolites' frame. lithium (li) forms an attractive cation for adsorbing n2 molecule better than o2 molecule on lsx http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:marwa.ali1607m@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2023.2.9 m. h. mohammed ali et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 81 87 82 zeolite when it is mixed with air [8]. talking about adsorbents' capacity and productivity leads to study the adsorption isotherms of the system used in this research since it gives information about the full benefit of the adsorbent. also, the study of adsorption kinetics makes a clear image of the rate of adsorption and the mechanism it followed. 1.2. adsorption isotherm models adsorption isotherms can be defined as suitable mathematical models to describe the distribution of the adsorbed ions between the adsorbent material and the solution at equilibrium. langmuir, freundlich, dubinin– radushkevich, and others [8, 9] came up with models of adsorption isotherms. langmuir model, which was made to represent gas/solid phase interaction, was used in comparing, and measuring the ability of different adsorbents to take up molecules [8]. langmuir's isotherm takes surface coverage into account by balancing the relative rates of adsorption and desorption (dynamic equilibrium). while adsorption depends on how much of the adsorbent surface is open, desorption depends on how much of the surface is covered [6]. one of several forms of the langmuir equation is eq. 1 [6]: 1 qe = [ 1 qₘ.kl ] 1 ce + 1 qₘ (1) where: qe = the amount of adsorbate adsorbed per gram of the adsorbent at equilibrium (mg. g-1), qm = maximum monolayer coverage capacity (mg. g-1), kl = langmuir isotherm constant (l.mg1), ce = the equilibrium concentration of adsorbate (mg. l-1). freundlich model assumed non-ideal adsorption; the adsorbent has a heterogeneous surface and the adsorption is not restricted to the formation of a monolayer. the model can be linearized as eq. 2 [9, 10]: 𝑙𝑛 𝑞𝑒 = 𝑙𝑛 𝐾𝑓 + (1/𝑛) 𝑙𝑛 𝐶𝑒 (2) where: qe = the amount of adsorbate adsorbed per gram of the adsorbent at equilibrium (mg. g-1), kf = freundlich isotherm constant (mg. g-1), n = adsorption intensity, ce = the equilibrium concentration of adsorbate (mg. l-1). generally, the dubinin–radushkevich isotherm is used to describe how a gaussian energy distribution on a heterogeneous surface lead to adsorption [11]. the model has often done a good job of fitting data for high solute activities and the middle range of concentrations. the equation describes this model is eq. 3 [11]: ln 𝑞𝑒 = ln 𝑞𝑚 − kdr 𝜀 2 (3) where: qe = the amount of adsorbate adsorbed per gram of the adsorbent at equilibrium (mg. g-1), qm = theoretical isotherm saturation capacity (mg. g-1), kdr = dubinin– radushkevich isotherm constant (mol2. kj 2),  = is the polyanion potential (kj. mol-1). 𝜀 can be estimated by the following eq. 4 [11]: 𝜀 = 𝑅𝑇 𝑙𝑛 (1 + 1/𝐶𝑒 ) (4) where: 𝑅 is the gas constant (8.31 j mol−1 k−1), t is the absolute temperature and ce is the equilibrium concentration of adsorbate (mg. l-1). the model is applied to indicate physical and chemical adsorption of metal ions as well as the free energy, e, which is defined per molecule of adsorbate (that is removing a molecule from its position in the sorption layer to the infinity) may be calculated by eq. 5 [11]: 𝐸 = (1 /√2𝐾) (5) 𝐸 is the mean adsorption energy less than 8 kj.mol-1 in physical adsorption but for the chemical adsorption the energy is between 8 to 16 kj.mol-1 [12]. this study focused on the adsorption isotherm models of n2 gas from ambient air on li-lsx zeolite to get medical oxygen as a necessary step in scaling – up the system. 1.3. adsorption kinetics kinetics studies the adsorption rates to explain the mechanism that dominates in a certain system. studying adsorption kinetics means investigating the experimental conditions that affect the rate of adsorption and, in turn, finding the factors that affect reaching equilibrium. these kinds of studies tell us about the possible way adsorption works and the different steps that lead to the final adsorbate–adsorbent complex. they also help come up with the right mathematical models to describe how things work together. once the rates and factors that affect them are clear, they can be used to make adsorbent materials for use in industry and to figure out how the dynamics of the adsorption process is complex [7]. adsorption kinetics are very important for figuring out the equilibrium adsorption capacity and the rate constants. the most common types of kinetic models are pseudofirst order and pseudo-second order. [13]. in pseudo-first order model, the adsorption capacity is related to the rate of adsorption as follows in eq. 8 [7]: 𝑙𝑛 (𝑞𝑒 − 𝑞𝑡) = 𝑙𝑛 𝑞𝑒 − 𝑘1 𝑡 (6) where: qe= adsorption capacity at equilibrium, mg. g-1, qt= adsorption capacity at any time, mg. g-1, k1 = rate constant for pseudo 1st order adsorption process, min -1. this model is found to be fit for the initial 20 to 30 min of interaction between the adsorbate and the adsorbent and not fit the overall extent of contacting [14]. while pseudo-second order, which ho and mckay established within 1998 [15] can be represented in the following eq. 7: (dq /dt) = k2 (qe qt) 2 (7) where: k2 = the ho-mckay equation's rate constant, g min.mg-1. m. h. mohammed ali et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 81 87 83 the pseudo-second-order kinetic model can be solved to take the linearized form as in eq. 8 [8]: 𝑡 𝑞𝑡 = 1 𝑘₂ 𝑞𝑒2 + t 𝑞𝑒 (8) the initial phases of the adsorption process are assumed to be described by the pseudo-first-order model but for the whole range of adsorption it is likely that the adsorption process follows a non-linear model that represents the complex mechanism of interaction between the absorbate and the adsorbent. for porous adsorbents, the diffusion of the adsorbate molecules into the pores needs to be considered when looking for a good kinetic model for the process. in many cases, the rate at which an adsorbate is taken in may be controlled by intra-particle diffusion. this is presented by the following well-known expression [16]. q𝑡 = 𝑘𝑖 ⋅t 0.5 (9) the crucial aspect of this formula is that the linear plot of q t vs t0.5 must pass through the origin (zero intercepts). consequently, the intra-particle diffusion model is easily testable, demonstrating that the diffusion process dominates the kinetics. the slope of the graph can be utilized to calculate the rate coefficient ki (mg/ (g. min 0.5) [17]. 2experimental work 2.1. materials zeolite li-lsx was used in the experiments. the technical specification of it is listed in table 1. table 1. the technical specification of li-lsx zeolite (commercial name jlox-101) property unit jlox-101 country diameter mm 0.4 – 0.8 china n2 adsorption capacity ml.g -1 ≥ 22 n2/o2 selectivity ⁓ ≥ 6.20 crush strength n ⁓ bulk density g.ml-1 0.63±0.03 moisture content wt.% ≤ 0.5 particle ratio % ≥ 95 2.2. equipment the experimental setup is shown in fig. 1. fig. 2 shows photos of the experimental setup. all the equipment used is listed in table 2. table 2. equipment used in the research # device specification range country 1 air compressor ingco industrial ,220-240v, ⁓50hz, ac25508 0-8 bar china 2 pressure gauge with filter unit filter unit d =2.5 cm, l = 5 cm pressure gauge 0-10 bar china 3 inlet flow meter pmb cv.p. a10.lm. g2 1-10 l.min-1 china 4 adsorption column glass type qvf, l= 17 cm, id= 4cm 5 pressure gauge 0-3 bar china 6 o2 gas sensor gdx-o2, l = 15.5 cm, d = 2.8 cm 0-100% o2 u. s. 7 purge flow meter matheson u310 0.5 6 l min-1 china 8 valves china 9 drum l= 60 cm, d= 37 cm v=64480 cm3 fig. 1. schematic diagram of experimental setup m. h. mohammed ali et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 81 87 84 fig. 2. view of the experimental setup 2.3. procedure at the beginning, the adsorbent (zeolite li-lsx) was heated for 45 minutes in an oven at 110 ℃ to eliminate moisture and other impurities. then zeolite was packed randomly in the column. helium gas was let to flow passing the packing for refreshing it and prepare it to adsorb n2. air was compressed to a specific pressure through the drum to maintain the flow of air to be stable in the column during the experiments. air was also passed through a filter filled with silica gel to get rid of moisture and impurities. the flow was set at a certain value of flow rate by a flow meter. nitrogen gas was adsorbed on the zeolite and oxygen-rich gas was produced at the outlet. the oxygen produced was split into two streams: one to the sensor for measuring oxygen purity one to the storage cylinder and the remainder as a volume percentage of the generated gas. nitrogen volume percent in the inlet and outlet was determined by subtracting the oxygen percent from total 100% complete air components. there was also a purge stream to manage any unusual increase in the outlet pressure. after each adsorption experiment, there was a desorption operation to regenerate the zeolite. the desorption operation was carried out under vacuum pressure of -0.9 bar for 2 minutes. the amount of adsorbed nitrogen was estimated by the difference between the inlet and outlet concentrations after converting the partial pressure to concentration considering nitrogen as an ideal gas at the experimental conditions. 2.4. response surface methodology the response surface approach was investigated. to investigate the interactions between the variables that affected the purity of o2. also, it was used for optimizing and scaling up the current laboratory setup. in this respect, experiments were designed using the boxbehnken design (bbd). fifteen experiments were carried out with various combinations of the studied variables which were: inlet pressure, packing height, and flow rate to determine which factors and their interactions had the major influence on the purity of the generated oxygen [18]. 3results and discussions 3.1. isotherm model the langmuir, dubinin – radushkevich, and freundlich isotherm models were used to examine the adsorption data. the adsorption isotherms were applied at the best operating conditions obtained in this study: 2.5 bar pressure, and 16 cm height of packing which gives the highest purity of oxygen (73.15 vol % of outlet gas) which was the basis for optimizing the results to reach the utmost purity required for medical purposes [18]. these models relate the quantity of nitrogen adsorbed on a solid surface fig. 3 to fig. 5 below explain the adsorption isotherm model (freundlich, dubinin-radushkevich, and langmuir) with the results in table 3. fig. 3. langmuir isotherm model for adsorption of nitrogen at 2.5 bar input pressure and 16 cm packing height fig. 4. freundlich isotherm model for adsorption of nitrogen at 2.5 bar input pressure and 16 cm packing height the results in table 3 show that all the models fit well the experimental data, but langmuir model has the maximum value of the correlation coefficient (r2=0.917). this led to the conclusion that the adsorption process followed langmuir hypotheses of monolayer of adsorbed molecules and that no forces of interaction existed between them [15]. langmuir parameters were the maximum capacity of adsorption 200 mg. g-1 which m. h. mohammed ali et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 81 87 85 indicated a large capacity for adsorption and kl 0.00234 l.mg-1 which indicated a favorable adsorption [16]. also, the apparent energy (e) was found to be +0.02 kj.mol-1 from drk isotherm model. the low positive value of energy agrees well with the heat of physical adsorption in the gas phase with n equal to 1.435 from the freundlich model [10, 12]. fig. 5. dubinin-radushkevich isotherm model for adsorption of nitrogen at 2.5 bar input pressure and 16 cm packing height table 3. langmuir, freundlich, and dubinin– radushkevich isotherm constants for the adsorption of nitrogen at 2.5 bar input pressure and 16 cm packing height isotherm model model parameter value 2r langmuir , mg/gmq 200 0.917 kl, l/mg 0.00234 freundlich , mg/ gfk 1.552 0.89 n, 1.435 dubinin 2/kj2mol d,k 1946.3 0.7219 3.2. adsorption kinetics the kinetic data for the adsorption of nitrogen on zeolite li-lsx adsorbent was three fundamental kinetic models were investigated: the pseudo-first-order model, the pseudo-second-order model, and the intra-particle kinetic model. fig. 6 through fig. 8 show the three models. table 4 lists the three kinetic models' correlation coefficients and other characteristics. the three models showed acceptable values of correlation coefficient (r2) with the pseudo-first order model (0.9834) somewhat higher than the others. the equilibrium capacity of pseudo-first order 63.79 mg /g was close enough to the experimental value 58.5 mg/g to make the decision that the pseudo – first order model represented well the kinetics of this system. therefore, the mechanism of which the adsorption followed as well as the speed of adsorption depicted nonlinear interaction between nitrogen gas molecules and li-lsx zeolite. table 4. kinetics models constants for adsorption of n2 on zeolite li-lsx at 2.5 bar pressure and 16 cm packing height kinetics model model constants model constant value k1 (l/min) 2.746 pseudo firstorder qe (mg/g) 63.79 r2 0.9834 k2 (g /mg. min) 0.048 pseudosecond order qe (mg/g) 217.391 r2 0.9772 intra particle ki (mg/g.min 1/2) 58 r2 0.9193 fig. 6. the pseudo-first-order kinetic model of n2 adsorption on zeolite li-lsx at 2.5 bar pressure and 16 cm packing height fig. 7. the pseudo-second-order kinetic model of n2 adsorption on zeolite li-lsx at 2.5 bar pressure and 16 cm packing height fig. 8. the intra-particle diffusion model of n2 adsorption on zeolite li-lsx at 2.5 bar pressure and 16 cm packing height m. h. mohammed ali et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 81 87 86 4conclusions the equilibrium sorption was investigated in a packed bed of zeolite li-lsx at pressure 2.5 bar, flow rate of 210 l.min-1, and height of packing of 16 cm for the adsorption of n2 from air to produce medical oxygen. the adsorption isotherm models were studied to get the necessary information of the adsorbent material that it confirmed its feasibility in industrial application. the sorption data were applied into langmuir, freundlich, and dubunin radushkevich isotherms. langmuir adsorption model was the best correlation represented the experimental data. all the models proved that the adsorption was physical in nature and the concept of one layer was applicable. the experimental data correlated well with the pseudo -first-order kinetic model which indicated the nonlinear interaction between nitrogen molecules and li-lsx zeolite. references [1] r. r. vemula, m. d. urich, and m. v. kothare, “experimental design of a ‘snap-on’ and standalone single-bed oxygen concentrator for medical applications,” adsorption, vol. 27, no. 4, 2021, https://doi.org/10.1007/s10450-021-00299-8 [2] a. arora and m. m. f. hasan, “flexible oxygen concentrators for medical applications,” sci. rep., vol. 11, no. 1, 2021, https://doi.org/10.1038/s41598021-93796-3 [3] s. qadir. d.li, y .gu, yuan, z. y .zhao, s. wang, s.wang, “experimental and numerical analysis on the enhanced separation performance of a medical oxygen concentrator through two-bed rapid pressure swing adsorption,” ind. eng. chem. res., vol. 60, no. 16, 2021, https://doi.org/10.1021/acs.iecr.1c00420 [4] a. a. tishin, “study of adsorption properties of zeolites nax, caa, and canaa in separation of air components,” pet. chem., vol. 60, no. 8, 2020, https://doi.org/10.1134/s0965544120080149 [5] x. yang, f. e. epiepang, j. li, y. wei, y. liu, and r. t. yang, “sr-lsx zeolite for air separation,” chem. eng. j., vol. 362, 2019, https://doi.org/10.1016/j.cej.2019.01.066 [6] r.t. yang, ʻʻgas separation by adsorption processes (vol. 1),1997. world scientific. https://doi.org/10.1142/p037 [7] a. günay, e. arslankaya, and i. tosun, ʻʻlead removal from aqueous solution by natural and pretreated climatariansʼʼ 2007.146(1-2), pp.362-371. https://doi.org/10.1016/j.jhazmat.2006.12.034 [8] t. m. elmorsi, “equilibrium isotherms and kinetic studies of removal of methylene blue dye by adsorption onto miswak leaves as a natural adsorbent,” j. environ. prot. (irvine,. calif)., vol. 02, no. 06, 2011, https://doi.org/10.4236/jep.2011.26093 [9] t. m. albayati, g. m. alwan, and o. s. mahdy, “high performance methyl orange capture on magnetic nanoporous mcm-41 prepared by incipient wetness impregnation method,” korean j. chem. eng., vol. 34, no. 1, 2017, https://doi.org/10.1007/s11814-016-0231-2 [10] n. ayawei, a. t. ekubo, d. wankasi, and e. d. dikio, “adsorption of congo red by ni/al-co3: equilibrium, thermodynamic and kinetic studies,” orient. j. chem., vol. 31, no. 3, 2015, https://doi.org/10.13005/ojc/310307 [11] s. k. lagergren, “about the theory of so-called adsorption of soluble substances,” sven. vetenskapsakad. handingarl, vol. 24, 1898. [12] q. hu and z. zhang, “application of dubinin– radushkevich isotherm model at the solid/solution interface: a theoretical analysis,” j. mol. liq., vol. 277, 2019, https://doi.org/10.1016/j.molliq.2019.01.005 [13] s. sen gupta and k. g. bhattacharyya, “kinetics of adsorption of metal ions on inorganic materials: a review,” advances in colloid and interface science, vol. 162, no. 1–2. 2011. https://doi.org/10.1016/j.cis.2010.12.004 [14] s. s. shah, i. ahmad, w. ahmad, m. ishaq, k. gul, r. khan, h.khan, “study on adsorptive capability of acid activated charcoal for desulphurization of model and commercial fuel oil samples,” j. environ. chem. eng., vol. 6, no. 4, 2018, https://doi.org/10.1016/j.jece.2018.06.008 [15] m. m. brdar, a. a. takači, m. b. šćiban, and d. z. rakić, “isotherms for the adsorption of cu(ii) onto lignin comparison of linear and non-linear methods,” hem. ind., vol. 66, no. 4, 2012, https://doi.org/10.2298/hemind111114003b [16] d. m. ruthven and s. farooq, “air separation by pressure swing adsorption,” gas sep. purif., vol. 4, no. 3, 1990, https://doi.org/10.1016/09504214(90)80016-e [17] w. j. weber and j. c. morris, “kinetics of adsorption on carbon from solution,” j. sanit. eng. div., vol. 89, no. 2, 1963, https://doi.org/10.1061/jsedai.0000430 [18] h.marwa , a. raghed, k. riyadh, “methodological approach for optimizing production of oxygen by adsorption of nitrogen from air using zeolite lilsx”, international journal of chemical engineering, 2022. https://doi.org/10.1155/2022/7254646 https://cir.nii.ac.jp/crid/1570009750361875328 https://cir.nii.ac.jp/crid/1570009750361875328 https://cir.nii.ac.jp/crid/1570009750361875328 https://doi.org/10.1016/0950-4214(90)80016-e https://doi.org/10.1016/0950-4214(90)80016-e m. h. mohammed ali et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 81 87 87 li-دراسة متساوية الحرارة والحركية المتزاز النيتروجين من الهواء باستخدام الزيواليت lsxإلنتاج األكسجين الطبي 2 رياض كامل عبدو ،1رغد فريد الملي ، ، *1مروة حسين محمد علي العراق بغداد،قسم الهندسة الكيمياوية، كلية الهندسة، جامعة بغداد، 1 العراق ، وزارة العلوم والتكنولوجيا،مركز بحوث النفط والبتروكيمياويات 2 الخالصة ة من وحركية امتزاز النيتروجين من الهواء باستخدام طبقة معبأ حرارة االمتزاز هذا البحث متساوي درسي حت ظروف تشغيل تاألوكسجين الناتج أجريت تجارب لتقدير نقاء . إلنتاج األوكسجين الطبي li-lsxالزيوليت وارتفاع التعبئة ( 1-دقيقة .لتر 01-2)، معدل تدفق الهواء الداخل (بار 2.5 0.5)ضغط اإلدخال : مختلفة اء لألوكسجين االمتزاز في أفضل الظروف التي أنتجت أعلى درجة نق حرارة تمت دراسة متساوي (. سم 9-16) بار 2.5ضغط إدخال هي:كانت هذه الظروف (. الغاز الخارج حجم من % 73.15 ( بواسطة هذا النظام رةحرا نماذج متساوي ان. عند درجة الحرارة المحيطة 1-دقيقة .لتر16سم ومعدل تدفق 16وارتفاع التعبئة كانت قيم(. drk)متساوي حرارة النكماير وفريوندليش ودوبينين رادوشكيفيتش التي بحثت كانت:االمتزاز كيفيتشو ودوبينين رادوش 0.89، فريوندليش0.917نموذج متساوي الحرارة النكماير: كالتالي 2r االرتباطمعامل ان موير كاوي الحرارة النج، لكن متسمثياًل جيًدا للبيانات التجريبيةأظهرت جميع النماذج المدروسة ت. 0.7219 kl 0.00234و 1-غم.مجم mq( 200( ، وكانت معلمات النموذج هي أقصى تغطية أحادية الطبقةاألفضل إلى امتصاص ( n)أيًضا ، من نموذج متساوي الحرارة فريوندليش ، أشارت شدة االمتصاص . 1-ملي غم.لتر ودوبينين رادوشكيفيتش الحرارة متساوي نموذج من الحرة الطاقةتم تقدير متوسط . 1.435إيجابي قدره لنتائج اأظهرت . الفيزيائية الطبيعةوالذي أثبت بوضوح أن تجربة االمتزاز اتبعت 1-كيلوجول . مول 0.02ليكون . التجريبية مطابقة جيدة للنموذج الحركي من الدرجة األولى الزائف .تزاز النتروجين، حركية االمتزاز، امكسجين الطبي، متساوي الحرارة لالمتصاص، األو li-lsxالزيوليت :دالةالكلمات ال available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.21 no.4 (december 2020) 41 – 48 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: layth a. jameel, , email: laith93jamil@gmail.com , name: fadhil s. kadhim, email: fadhilkadhim47@yahoo.com , name: hussein ilaibi al-sudani , email: dr.hussein_alsudani@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. petrophysical properties of khasib formation in east baghdad oil field southern area layth a. jameel, fadhil s. kadhim and hussein ilaibi al-sudani petroleum technology department, university of technology, baghdad, iraq abstract petrophysical properties evaluation from well log analysis has always been crucial for the identification and assessment of hydrocarbon bearing zones. east baghdad field is located 10 km east of baghdad city, where the southern area includes the two southern portions of the field, khasib formation is the main reservoir of east baghdad oil field. in this paper, well log data of nine wells have been environmentally corrected, where the corrected data used to determine lithology, shale volume, porosity, and water saturation. lithology identified by two methods; neutron-density and m-n matrix plots, while the shale volume estimated by single shale indicator and dual shale indicator, the porosity is calculated from the three common porosity logs; density log, neutron log, and sonic log, the water saturation is calculated by indonesian model and archie equation, and the results of the two methods were compared with the available core data to check the validity of the calculation. the results show that the main lithology in the reservoir is limestone, shale volume ranged between 0.152 to 0.249, porosity between 0.147 to 0.220, and water saturation from 0.627 to 0.966, the high-water saturation indicate that the water quantity is the determining factor of the reservoir units. keywords: petrophysical properties, well logs analysis, carbonate formation. received on 04/02/2020, accepted on 21/09/2020, published on 30/12/2020 https://doi.org/10.31699/ijcpe.2020.4.5 1introduction carbonate reservoirs contain more than 60% of the world's oil reserves and contribute to more than 30% of the world's daily oil production. these carbonate reservoirs are more challenging when estimating the petrophysical properties and understanding the fluid flow mechanisms, compared to most sandstone reservoirs. fluid flow through heterogeneous carbonate reservoirs is a very different and challenging process from the flow through homogeneous sandstone reservoir, as carbonate rocks tend to have a more complex pore system than sandstone [1], also the greater chemical reactivity of carbonate minerals, as carbonate rocks are mostly composed of calcite which is reactive to formation brine [2]. formation evaluation is the process of interpreting a combination of measurements taken from inside the wellbore to evaluate wells for potential hydrocarbon bearing rocks, these measurements could be cores, laboratory measurements of fluid properties, and well logs. well logs are considered one of the main sources of data for the geological and petrophysical parameters of reservoir formations; well logging plays a crucial role in the determination of the production potential of a hydrocarbon reservoir [3]. this study aims to determine the main petrophysical properties and lithology of khasib formation in the east baghdad southern area oil field. the field is newly under development and the study is aimed to give a better understanding of the reservoir characteristics to provide tools for future field economic feasible-development plans. 1.1. area of case study east baghdad is a super-giant oil field located in baghdad and saladin governorates, 10 km east of baghdad city. the contract area for the east baghdad field covers the portion north-west of the diyala river and is 65 kilometers long and 11 kilometers wide. east baghdad holds 8 billion barrels proven reserves. east baghdad oil field is subdivided geographically into six areas, from northwest to southeast; respectively north extension, al-taji, al-rashdiya, urban, south 2, and south 1 areas [4]. east baghdad's southern area includes both south 2 and south 1. fig. 1 shows the location of the east baghdad oil field on the iraq oil location map. khasib formation is the main reservoir of the east baghdad oil field [5], it is bounded by tanuma formation at the top and kifil formation at the bottom. khasib formation is subdivided into nine zones; k1 to k9, based on the recognition of depositional cycles and lithological changes [6]. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:laith93jamil@gmail.com mailto:fadhilkadhim47@yahoo.com mailto:dr.hussein_alsudani@yahoo.com http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2020.4.5 l. a. jameel et al. / iraqi journal of chemical and petroleum engineering 21,4 (2020) 41 48 42 fig. 1. iraq oil location map [7] 2methodology interactive petrophysics software (ip v3.5, 2009) has been used for correction and interpretation. nine wells from the east baghdad southern area have been used in this study, as provided by the reservoir department/ministry of oil. the wells are eb4, eb5, eb15, eb18, eb26, eb30, eb38, eb48, and eb54, all these wells are exploration wells, no production wells have been drilled before in this field. the data were used from available well log records in form of las-files; such as potential spontaneous records (sp), gamma rays, density, sonic, neutrons, and resistivity. the workflow diagram is shown in fig. 2. fig. 2. well logs interpretations methodology flow diagram 3results and discussion 3.1. environmental correction the environmental corrections were carried out by the environment correction module provided by interactive petrophysics (ip v4.2) software. as shown in fig. 3, schlumberger log interpretation charts (2000 edition) has been used as the well log data are provided by schlumberger oilfield services company. the results show a noticeable increase in gamma-ray readings, gamma-ray is corrected to mud properties (mud type and weight) and borehole condition, while the borehole has no cavities as caliper log shows, then the mud properties were the determining factor in this change. induction resistivity shows no change between readings which indicates that the raw logs readings were not affected by drilling mud in the invention zone. fig. 3. schlumberger environmental correction window from ip software fig. 4. environmental correction log plot of eb30 (generated by ip software) l. a. jameel et al. / iraqi journal of chemical and petroleum engineering 21,4 (2020) 41 48 43 micro resistivity log and density log show a minor change in their readings due to drilling mud and the logging used tools. neutron density shows clear shifting between the readings, the corrected readings were increased; neutron log is affected by many parameters such as drilling mud and formation proprieties and lithology. fig. 4 shows a log plot of the corrections of well eb30, the green solid lines represent the logs reading while the red dot lines represent the corrected reading. 3.2. lithology identification the concept behind lithology identification is the distinct responses porosity logs show to different types of minerals. any combination of the three porosities logs (density, neutron, and sonic logs) can give an appropriate indication of the formation lithology [8]. density-neutron plot is a cross plot with neutron log readings on the x-axis versus density log readings on the y-axis, whereby the use of gamma-ray rangesthe mineral type is presented and clearly shown. fig. 5 shows the density-neutron plot of well eb18, the results show that the dominant mineral matrix in the formation is limestone; this result is compatible with the geological reports of the wells which identify khasib formation as limestone porous. m-n plot is generated from the interpretations of density, neutron, and sonic logs. m and n are lithology dependent parameters. fig. 5. density – neutron lithology cross plot of eb18 (generated by ip software) fig. 6 shows the m-n plot of well eb18. m-n plot illustrates that the formation consists of limestone, as the major accumulation of the points is in the carbonate zone. also, it can be seen that no reasonable secondary porosity in the formation, and there is no need to consider the secondary porosity when evaluating the formation porosity. due to these results, limestone parameters have been used -when neededwith other formation calculations. fig. 6. m-n lithology cross plot of eb18 (generated by ip software) 3.3. shale volume calculation one of the most controversial issues in the formation evaluation is the shale effect on the rocks of the reservoir. shale is usually more radioactive than sand or carbonate. therefore, gamma-ray log and other logs can be used to calculate the volume of shale in a porous medium [9]. three different shale indicators were used to estimate shale volume; gamma-ray, sp, and neutron-density. for each indicator a result shale volume was obtained; vclgr from the gamma-ray log, vlcsp from sp log and vclnd from neutron-density logs. to avoid logging tools high readings errors, minimum shale volume (vcl) represents the target result from shale volume calculations, by which, shale volume of the formation was presented, as vcl represents the minimum shale response of all used indicators [10]. fig. 7 shows an example of shale volume results curves; each tool curve track is followed by a shale curve interpreted from it, while the last track shows the minimum shale volume as it represents the result of all the indicators combined. the results show a noticeable variation in shale volume through the wells tracks, which explain the division of the formation into nine zones, these zones are presented for well eb04 in figure 5 and can be seen in the second track. the average shale volume for each well is presented in the table 1. l. a. jameel et al. / iraqi journal of chemical and petroleum engineering 21,4 (2020) 41 48 44 fig. 7. shale volume log plot of eb04 (generated by ip software) table 1. all wells shale volume results as interpreted from well logs well well interval, m shale volume (vcl) eb04 2429 2537 0.249 eb05 2493 2623 0.183 eb15 2547 2661 0.162 eb18 2510 2625 0.209 eb26 2440 2550 0.221 eb30 2539 2656 0.163 eb38 2425 2522 0.152 eb48 2494 2607 0.152 eb54 2459. 2574 0.197 3.4. porosity estimation porosity is one of the most important reservoir properties as it represents the potential storage volume for hydrocarbons. in carbonate reservoirs, the porosity values range from 1% to 35% [11]. porosity is measured either from core samples in the laboratory or from porosity well logs interpretations [12]. in this study, porosity was calculated from the three porosity logs (density, neutron, and sonic). also, effective porosity was calculated by excluding the volume of shale from the total porosity. fig. 8 shows an example of porosity results, density porosity (phiden), neutron porosity (phineu), and sonic porosity (phison) is shown in tracks 2, 3, and 4 in a row, while the last track shows the effective porosity (phie). the validation of the results is checked by comparing the predicted effective porosity with core porosity [13]. table 2 illustrates effective porosity interrupted from well logs and porosity of core samples for the cored intervals as available in this study-. to present the prediction accuracy, the absolute percent error is calculated as follows: 𝐴𝑃𝐸 = | 𝑃𝐻𝐼𝑙𝑜𝑔−𝑃𝐻𝐼𝑐𝑜𝑟𝑒 𝑃𝐻𝐼𝑐𝑜𝑟𝑒 | × 100% (1) where, philog is predicted porosity and phicore is core samples porosity. the results of the absolute percentage error ranged from 1.07 to 6.63 percent. correlation between log porosity and core porosity has been made to gain more accurate results; where the correlation coefficient ( r2) of this correlation equals 0.856563. equation (2) is the correction equation generated from statistical analysis as shown in fig. 9. 𝑃𝐻𝐼𝑙𝑜𝑔 = −0.02667853 + (1.080926228 × 𝑃𝐻𝐼𝑐𝑜𝑟𝑒 ) (2) fig. 8. porosity results log plot of eb15 (generated by ip software) table 2. comparison of log porosity versus core porosity for available cored wells well interval, m log porosity core porosity ape % eb04 2429 2470 0.264 0.258 2.32 eb05 2498 2533 0.189 0.187 1.07 eb26 2443 2478 0.235 0.238 1.26 eb30 2541 2578 0.169 0.181 6.63 fig. 9. core porosity versus log porosity cross plot (generated by ip software) l. a. jameel et al. / iraqi journal of chemical and petroleum engineering 21,4 (2020) 41 48 45 the predicted porosity is corrected by equation (3), which was produced by simple manipulation to equation (2); by solving the equation to phicore and consider it as the corrected porosity (phic). 𝑃𝐻𝐼𝐶 = 𝑃𝐻𝐼𝑙𝑜𝑔+0.02667853 1.080926228 (3) from the corrected porosity, average porosity has been calculated for each well understudy, as illustrated in table 3. the results show a variation of porosity between wells due to formation heterogeneity, the porosity ranged from 0.220 to 0.147. table 3. all wells porosity results as interpreted from well logs well well interval, m porosity eb04 2429 2537 0.209 eb05 2493 2623 0.192 eb15 2547 2661 0.198 eb18 2510 2625 0.176 eb26 2440 2550 0.213 eb30 2539 2656 0.214 eb38 2425 2522 0.176 eb48 2494 2607 0.220 eb54 2459. 2574 0.147 3.4. water saturation calculations water saturation is one of the most important petrophysical parameters information evaluation. water saturation is used to estimate oil in place, perforation zones detection also depends mainly on the knowledge of water saturation in the formations [14]. empirical methods are used to calculate water saturation from well logs, depending mainly on resistivity measurements. indonesian model and the archie equation are two of the most used methods for the calculations [15]. fig. 10 shows pickett’s plot for well eb48, in the figure, the red line represents 100% water saturation, while the three blue lines represent the water saturation of 50%, 30%, and 20% depending on its distance from the red line (closest is the highest). the slope value of the 100% water saturation line is the cementation factor. table 4 illustrates the values of (rw, m, n, and a) for each well in this study. a log plot example of water saturation results from archie and indonesian methods is shown in fig. 11; water saturation obtained from archie method (swarch) is presented in the second track, while the third track shows the result of indonesian method (swind), also water saturation of core plug samples (swcore) is shown in both of the tracks by red dots. fig. 10. pickett’s plot of eb48 (generated by ip software) table 4. all wells archie parameters well rw m n a eb04 0.0255 1.8 2 1 eb05 0.0268 1.9 2 1 eb15 0.0250 1.8 2 1 eb18 0.0371 1.52 2 1 eb26 0.0259 1.83 2 1 eb30 0.0224 1.73 2 1 eb38 0.0305 1.48 2 1 eb48 0.0247 1.63 2 1 eb54 0.0427 1.44 2 1 fig. 11. water saturation log plot of eb26 (generated by ip software) table 5 shows a comparison of average water saturation from archie and indonesian methods with water saturation measured from core samples. to determine the most accurate method, the absolute percentage error is calculated. the results of the indonesian method are closer to core water saturation with ape ranged from 0.9 to 9.2 percent, while archie shows a large lack of accuracy with errors ranged from 7.2 to 33 percent. l. a. jameel et al. / iraqi journal of chemical and petroleum engineering 21,4 (2020) 41 48 46 the main reason behind archie's method's poor results is that the formation contains relatively high shale volume, as well as the presence of pyrite in the invaded zone, as pyrite was used in the drilling mud. shale and pyrite are conductive minerals which is one of archie method limitations [16]. indonesian method on the other hand was successful because it had been derived originally to study water saturation in a carbonate reservoir. table 5. comparison of swarch and swind with swcore for available cored wells well interval, m swcore swarch ape swind ape eb05 2540 – 2550 0.39 0.362 7.2 0.414 6.1 eb26 2440 – 2470 0.292 0.326 11.6 0.319 9.2 eb30 2572–2597.6 0.597 0.671 12.3 0.548 8.2 eb38 2387.5–2457 0.555 0.5 9.9 0.54 2.7 eb48 2496.5–2510 0.477 0.32 33 0.497 4.2 eb54 2524 – 2548 0.428 0.309 27.8 0.432 0.9 table 6 illustrates the average water saturation of all wells. the results show a maximum water saturation of 96.6% in well eb15, while the minimum percent is in well eb04 with 62.7% of water saturation; these results indicate that the formation primarily fluid is water. table 6. all wells water saturation results as interpreted from well logs well well interval, m water saturation eb04 2429 2537 0.627 eb05 2493 2623 0.692 eb15 2547 2661 0.966 eb18 2510 2625 0.777 eb26 2440 2550 0.633 eb30 2539 2656 0.796 eb38 2425 2522 0.740 eb48 2494 2607 0.854 eb54 2459. 2574 0.787 4conclusions petrophysical analysis has been carried out for reservoir characterization of khasib formation in east baghdad southern area oil fields, using a suite of well log data from nine wells in the field. lithological interpretation determines the main lithology of the formation as limestone, porosity ranged from 0.147 to 0.220, which is the normal ranges of carbonate reservoirs and water saturation ranged from 0.627 to 0.966. the high-water saturation and its variation through depth and well locations make it the determining factor to identify the pay zones. computer processed interpretation (cpi) of the wells indicates that the pay zones of the reservoir are the upper zones (upper khasib), these zones contain the lowest water saturations, around 50%, unlike the lower zones where water saturations exceed 90%. many wells show a high-water saturation at all the reservoir zones, which means that these wells are drilled in all water portions of the reservoir, these portions should be avoided in future field developments. nomenclature ape: absolute percentage error a: tortuosity factor gr: gamma-ray m: cementation factor n: saturation exponent. phi: porosity sp: spontaneous potential sw: water saturation vlc: shale volume references [1] n. hurley, "quantification of vuggy porosity in a dolomite reservoir from borehole images and core, dagger draw field, new mexico," in annual technical conference and exhibition, new orleans, louisiana, 1998. [2] s. ehrenberg and p. h. nadeau, "sandstone vs. carbonate petroleum reservoirs: a global perspective on porosity-depth and porosity-permeability relationships," aapg bulletin, vol. 89, no. 4, pp. 435445, 2005. [3] f. aminzadeh and s. n. dasgupta, "geophysics in drilling." in developments in petroleum science, vol. 60, pp. 223-246. elsevier, 2013. [4] mdoc official web site," [online]. retrieved from http://www.mdoc.oil.gov.iq [5] m. s. al-jawad and k. a. kareem, "geological model of khasib reservoircentral area/east baghdad field," iraqi journal of chemical and petroleum engineering, vol. 17, no. 3, pp. 1-10, 2016. [6] b. al-qayim, f. al-saadoni, and a. al-biaty, "diagenetic evolution of the khasib formation eastbaghdad oil field," iraqi geological journal, pp. 5672, 1993. [7] t. k. al-ameri and r. y. al-obaydi, "cretaceous petroleum system of the khasib and tannuma oil reservoir, east baghdad oil field, iraq," arab j geosci, 2011. [8] c. dawei, y. xuanjun, z. chuanmin, t. cong and w. mengshi, "logging-lithology identification methods and their application: a case study on," china petroleum exploration, 2016. [9] g. asquith and d. krygowski, basic well log analysis, 2nd ed., aapg, 2006. https://www.onepetro.org/conference-paper/spe-49323-ms https://www.onepetro.org/conference-paper/spe-49323-ms https://www.onepetro.org/conference-paper/spe-49323-ms https://www.onepetro.org/conference-paper/spe-49323-ms https://www.onepetro.org/conference-paper/spe-49323-ms https://pubs.geoscienceworld.org/aapgbull/article-abstract/89/4/435/40213 https://pubs.geoscienceworld.org/aapgbull/article-abstract/89/4/435/40213 https://pubs.geoscienceworld.org/aapgbull/article-abstract/89/4/435/40213 https://pubs.geoscienceworld.org/aapgbull/article-abstract/89/4/435/40213 https://pubs.geoscienceworld.org/aapgbull/article-abstract/89/4/435/40213 https://www.sciencedirect.com/science/article/pii/b9780444506627000032 https://www.sciencedirect.com/science/article/pii/b9780444506627000032 https://www.sciencedirect.com/science/article/pii/b9780444506627000032 http://www.mdoc.oil.gov.iq/ http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/209 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/209 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/209 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/209 https://d1wqtxts1xzle7.cloudfront.net/51457074/diagenetic_evolution_of_the_khasib_forma20170121-6571-1iamcvb.pdf?1485035680=&response-content-disposition=inline%3b+filename%3ddiagenetic_evolution_of_the_khasib_forma.pdf&expires=1608910583&signature=g5cweuo0kqwgkl7lxetxeoh94edxuk73e4jct3ye6lbi6kh62eryd7c8ycyvsn3b0sbtkvsjtk6kuc5joyp5fdnd8fplfyf4kv70ii63anjdd4uzdb9nl~i4fml0mmmanoil7r5n32vd3w~y0i1sgwd3rl6lvsubhacf95vw2eifnbratdbahwgm6ol2ronetl5pqxdf6yjfujjl3u~grkjtnmlmae2xsxnysyspnehncmduid6lhdc5q7hwvw3qlvcxx7us5arpbhkgrtbqjo8x9fr9ygbo1t3n0hru2odpz3adtipd0hljzcsb2hbml4oodu8mftsojopkpb4esa__&key-pair-id=apkajlohf5ggslrbv4za https://d1wqtxts1xzle7.cloudfront.net/51457074/diagenetic_evolution_of_the_khasib_forma20170121-6571-1iamcvb.pdf?1485035680=&response-content-disposition=inline%3b+filename%3ddiagenetic_evolution_of_the_khasib_forma.pdf&expires=1608910583&signature=g5cweuo0kqwgkl7lxetxeoh94edxuk73e4jct3ye6lbi6kh62eryd7c8ycyvsn3b0sbtkvsjtk6kuc5joyp5fdnd8fplfyf4kv70ii63anjdd4uzdb9nl~i4fml0mmmanoil7r5n32vd3w~y0i1sgwd3rl6lvsubhacf95vw2eifnbratdbahwgm6ol2ronetl5pqxdf6yjfujjl3u~grkjtnmlmae2xsxnysyspnehncmduid6lhdc5q7hwvw3qlvcxx7us5arpbhkgrtbqjo8x9fr9ygbo1t3n0hru2odpz3adtipd0hljzcsb2hbml4oodu8mftsojopkpb4esa__&key-pair-id=apkajlohf5ggslrbv4za https://d1wqtxts1xzle7.cloudfront.net/51457074/diagenetic_evolution_of_the_khasib_forma20170121-6571-1iamcvb.pdf?1485035680=&response-content-disposition=inline%3b+filename%3ddiagenetic_evolution_of_the_khasib_forma.pdf&expires=1608910583&signature=g5cweuo0kqwgkl7lxetxeoh94edxuk73e4jct3ye6lbi6kh62eryd7c8ycyvsn3b0sbtkvsjtk6kuc5joyp5fdnd8fplfyf4kv70ii63anjdd4uzdb9nl~i4fml0mmmanoil7r5n32vd3w~y0i1sgwd3rl6lvsubhacf95vw2eifnbratdbahwgm6ol2ronetl5pqxdf6yjfujjl3u~grkjtnmlmae2xsxnysyspnehncmduid6lhdc5q7hwvw3qlvcxx7us5arpbhkgrtbqjo8x9fr9ygbo1t3n0hru2odpz3adtipd0hljzcsb2hbml4oodu8mftsojopkpb4esa__&key-pair-id=apkajlohf5ggslrbv4za https://d1wqtxts1xzle7.cloudfront.net/51457074/diagenetic_evolution_of_the_khasib_forma20170121-6571-1iamcvb.pdf?1485035680=&response-content-disposition=inline%3b+filename%3ddiagenetic_evolution_of_the_khasib_forma.pdf&expires=1608910583&signature=g5cweuo0kqwgkl7lxetxeoh94edxuk73e4jct3ye6lbi6kh62eryd7c8ycyvsn3b0sbtkvsjtk6kuc5joyp5fdnd8fplfyf4kv70ii63anjdd4uzdb9nl~i4fml0mmmanoil7r5n32vd3w~y0i1sgwd3rl6lvsubhacf95vw2eifnbratdbahwgm6ol2ronetl5pqxdf6yjfujjl3u~grkjtnmlmae2xsxnysyspnehncmduid6lhdc5q7hwvw3qlvcxx7us5arpbhkgrtbqjo8x9fr9ygbo1t3n0hru2odpz3adtipd0hljzcsb2hbml4oodu8mftsojopkpb4esa__&key-pair-id=apkajlohf5ggslrbv4za https://link.springer.com/article/10.1007/s12517-009-0115-4 https://link.springer.com/article/10.1007/s12517-009-0115-4 https://link.springer.com/article/10.1007/s12517-009-0115-4 https://link.springer.com/article/10.1007/s12517-009-0115-4 http://www.cped.cn/en/abstract/abstract3017.shtml http://www.cped.cn/en/abstract/abstract3017.shtml http://www.cped.cn/en/abstract/abstract3017.shtml http://www.cped.cn/en/abstract/abstract3017.shtml http://members.aapg.org/eseries/staticcontent/aapg_files/html/bio707.html http://members.aapg.org/eseries/staticcontent/aapg_files/html/bio707.html l. a. jameel et al. / iraqi journal of chemical and petroleum engineering 21,4 (2020) 41 48 47 [10] e. frost jr, "method for estimation of bulk shale volume in a real-time logging-while-drilling environment". united states of america patent us 9,551,213 b2, 24 jan 2017. [11] f. j. lucia, carbonate reservoir characterization: an integrated approach. springer science & business media, 2007. [12] gb asquith, d krygowski, cr gibson, basic well log analysis. vol. 16. tulsa: american association of petroleum geologists, 2004. [13] smith, m. m, hao, yue, spangler, l. h, lammers, kristin, carroll and s. a, "validation of a reactive transport model for predicting changes in porosity and permeability in carbonate core samples," international journal of greenhouse gas control, vol. 90, p. 102797, 2019. [14] j.-r. ursin and a. b. zolotukhin, "fundamentals of petroleum reservoir engineering." (1997). [15] l. m. entyre, "comparative performance of a dual water model equation in laminar shaly sands," 1993. [16] yu, hongyan, wei, xiaolong, wang, zhenliang, rezaee, reza, zhang, yihuai, lebedev, maxim, iglauer, stefan and others, "review of water saturation calculation methods in shale gas reservoir," in spe asia pacific oil and gas conference and exhibition, 2018. https://patents.google.com/patent/us9551213/en https://patents.google.com/patent/us9551213/en https://patents.google.com/patent/us9551213/en https://patents.google.com/patent/us9551213/en https://books.google.iq/books?hl=en&lr=&id=nlzhr0mpxf0c&oi=fnd&pg=pa1&dq=%5b11%5d%09f.+j.+lucia,+carbonate+reservoir+characterization,+2nd+ed.,+2007.+&ots=kcdtzqp5xx&sig=sclmuaa_awzabxvsxlzzrjudqo4&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=nlzhr0mpxf0c&oi=fnd&pg=pa1&dq=%5b11%5d%09f.+j.+lucia,+carbonate+reservoir+characterization,+2nd+ed.,+2007.+&ots=kcdtzqp5xx&sig=sclmuaa_awzabxvsxlzzrjudqo4&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=nlzhr0mpxf0c&oi=fnd&pg=pa1&dq=%5b11%5d%09f.+j.+lucia,+carbonate+reservoir+characterization,+2nd+ed.,+2007.+&ots=kcdtzqp5xx&sig=sclmuaa_awzabxvsxlzzrjudqo4&redir_esc=y#v=onepage&q&f=false http://members.aapg.org/eseries/staticcontent/aapg_files/html/bio707.html http://members.aapg.org/eseries/staticcontent/aapg_files/html/bio707.html http://members.aapg.org/eseries/staticcontent/aapg_files/html/bio707.html https://www.sciencedirect.com/science/article/abs/pii/s1750583619301768 https://www.sciencedirect.com/science/article/abs/pii/s1750583619301768 https://www.sciencedirect.com/science/article/abs/pii/s1750583619301768 https://www.sciencedirect.com/science/article/abs/pii/s1750583619301768 https://www.sciencedirect.com/science/article/abs/pii/s1750583619301768 https://www.sciencedirect.com/science/article/abs/pii/s1750583619301768 https://www.onepetro.org/conference-paper/spwla-1993-i https://www.onepetro.org/conference-paper/spwla-1993-i https://www.onepetro.org/conference-paper/spwla-1993-i https://www.onepetro.org/conference-paper/spe-192115-ms https://www.onepetro.org/conference-paper/spe-192115-ms https://www.onepetro.org/conference-paper/spe-192115-ms https://www.onepetro.org/conference-paper/spe-192115-ms https://www.onepetro.org/conference-paper/spe-192115-ms https://www.onepetro.org/conference-paper/spe-192115-ms l. a. jameel et al. / iraqi journal of chemical and petroleum engineering 21,4 (2020) 41 48 48 في حقل شرق بغداد المنطقة الجنوبية الخصيب الخواص البتروفيزيائية لتكوين حسين لعيبي السوداني وليث عبد المالك جميل ، فاضل سرحان كاظم قسم تكنلوجيا النفط ، الجامعة التكنلوجية ، بغداد ، العراق الخالصة وة اساسية لتحديد وتقييم المناطق الحاملة يعتبر تحليل سجل اآلبار وتقييم الخواص البتروفيزيائية خط كم شرق مدينة بغداد ، حيث تضم المنطقة الجنوبية الجزأين 10للهيدروكربونات. يقع حقل شرق بغداد على بعد الجنوبيين من الحقل ، ويعتبر تكوين الخصيب المكمن الرئيسي لحقل شرق بغداد النفطي. لبيئية لبيانات سجل اآلبار والتي تشمل بيانات تسعة آبار من الحقل. في هذه البحث ، تم اجراء التصحيحات ا استخدمت البيانات المصححة لتحديد ليثولوجيا التكوين وكمية الطفل والمسامية وتشبع الماء. تم تحديد الليثولوجيا ب حجم الطفل بالمؤشرات أن( ورسم سجل الكثافة مقابل سجل النيوترون. في حين تم احتسا-بطريقتين: رسم )أم المسامية من خالل سجالت المسامية الثالثة: سجل الكثافة وسجل النيوترون وسجل االحادية والمزدوجة ، و الصوتية. اما تشبع الماء فتم حسابه بالموديل االندونيسي وبمعادلة آرتشي ، وتمت مقارنة نتائج الطريقتين احة لتحديد الطريقة االكثر دقة.بالبيانات المستخرجة من تحليل اللباب المت تشير النتائج إلى أن التكوين الصخري الرئيسي في المكمن هو الحجر الجيري ، وتراوح حجم الطفل بين . ان معدالت 0.966إلى 0.627وتشبع الماء بين 0.220إلى 0.147والمسامية بين 0.249الى 0.152 الماء هو العامل البتروفيزيائي االساسي لتحديد الوحدات المكمنية التشبع المائي العالية تبين ان قراءة تشبع الرئيسية للتكوين. الكلمات الدالة: خواص بتروفيزيائية ، تفسير مجسات االبار ، تكوينات كاربونية iraqi journal of chemical and petroleum engineering vol.16 no.4 (december 2015) 5965 issn: 1997-4884 effect of particle size of sawdust on behaviour of sawdust/upe composites in water nisreen s. ali * and besma m. fahad material engineering department, college of engineering, university of al-mustansiriyah *corresponding author e-mail:nisreenalazawi@yahoo.com abstract the aim of the present work is to develop a new class of natural fillers based polymer composites with sawdust (s.d) which used two particle sizes (1.2 μm & 2.3 μm) and different weight percentage from sawdust (10%, 15%, and 20%). the mechanical properties studied include hardness (shore d) for all samples at normal conditions (n.c). the unsaturated polyester (upe) and its composites samples were immersed in water for 30 days to find the effect of particle size of sawdust (s.d) on the weight gain (mt %) by water for all the samples, also to find the effect of water on their hardness. the results show that the composite materials of sawdust (s.d) fillers which has particle size (1.2 μm) better than (2.3 μm) particle size before & after the immersion in water. also the results show a decrease in the values of the hardness for the upe and its composites samples after immersion in water. the results show that the upe and its composites samples have relatively increased values of weight gain (mt %) by water with time of immersion, for sawdust composite samples (1.2 μm) particle size the samples of (15%) weight percentage have relatively highest values of weight gain (mt %) by water but for samples of (2.3 μm) particle size the samples of (20 %) weight percentage have relatively highest values of weight gain (mt %). finally results show that the value of weight gain (mt %) increased with increasing of particle size of sawdust so that the composites samples have highest value of weight gain (mt %) than upe sample. key words: sawdust, unsaturated polyester, hardness, absorbance of water. introduction composite is generally defined as any physical combination of two or more dissimilar materials used to produce a new material which is that cannot be obtained by each component individually. composites consist of one or more discontinuous phases embedded in continuous phase. the discontinuous phase is usually harder and stronger than the continuous phase and is called the reinforcement, reinforcing material or fillers, whereas the continuous phase is termed the matrix. the boundaries between the two phases are called interface. the properties of composites are strongly influenced by the properties of their constituent materials, their distribution and the interaction between them. besides specifying the constituent materials and their properties, a iraqi journal of chemical and petroleum engineering university of baghdad college of engineering effect of particle size of sawdust on behaviour of sawdust/upe composites in water 60 ijcpe vol.16 no.4 (dec. 2015) -available online at: www.iasj.net composite material as a system is described by the geometry of the reinforcement that may be described by the following factors: shape, size and size distribution of reinforcing materials. concentration, concentration distribution and orientation of reinforcing materials [1, 2]. unsaturated polyesters resin is a linear polymer with low molecule weight. the polyester backbone contains double bonds and carboxylic groups. in general, unsaturated polyester resin is prepared by the process of condensation polymerization for three basic components: saturated carboxylic acids, unsaturated carboxylic acids and glycols with splitting out water, and increasing in molecular weight by process called esterification. the general purpose of polyester is the product of phthalic acid, maleic acid and propylene glycol [3, 4, and 5]. on the past decade, it was seen fast and steady growth of wood plastics industry. among many reasons for the commercial success, the low cost and reinforcing capacity of the wood fillers provide new opportunities to manufacture composite materials. although the use of wood-based fillers is not as popular as the use of mineral or inorganic fillers, wood-derived fillers have several advantages over traditional fillers and reinforcing materials: low density, flexibility, during the processing with no harm to the equipment, acceptable specific strength properties and low cost per volume basis. the main application areas of wood flour filled composites are the automotive and building industries in which they are used in structural applications as fencing, decking, outdoor furniture, window parts, roofline products, door panels, etc. the environmental awareness of people today is forcing the industries to choose natural materials as substitutes for non-renewable materials. wood has been used as building and engineering material since early times and offers the advantages of not just being aesthetically pleasing but also renewable, recyclable and biodegradable [6, 7]. pothan et al., (1997) [8] studied the short banana fiber reinforced polyester composite concentrated on the effect of fiber length and fiber content. the maximum tensile strength was observed at 30 mm fiber length while maximum impact strength was observed at 40 mm fiber length. incorporation of 40% untreated fibers provides a 20% increase in the tensile strength and a 34% increase in impact strength. mishra et al. (2003) [9] studied the mechanical performance of biofiber / glass reinforced polyester hybrid composites. they found that addition of small amount of glass fibers in the pineapple leaf fiber and sisal fiber reinforced polyester showed positive hybrid effect which improved the mechanical properties of these composites. lalyetal. (2003) [10] have investigated banana fiber reinforced polyester composites and found that the optimum content of banana fiber is 40%. ahmed, (2004) [11] found that the composite materials were prepared from unsaturated polyester resin with different types of flakes (wood flour and rice husk), also a hybrid was prepared using the two kinds that mentioned above, with the almost the same volume fraction. results showed that the composite materials of (wood flour) gained better mechanical properties compared with others, the hybrid gained better thermal insulation compared with rice husk and wood flour composite. nisreen s. ali and besma m. fahad -available online at: www.iasj.net ijcpe vol.16 no.4 (dec. 2015) 61 mosadeghzad et al, (2009) [12] found that the polyethylene therephthalate (pet) waste bottles had been depolymerized by glycolysis and reduced to its monomer and dimer. the glycolysed product was used to produce unsaturated polyester resin (upr). dsc and ftir analysis were conducted on the resin and the glycolysed product. the resin was then mixed with sawdust (acacia) to produce the sawdust/upr composite based on recycled pet. the effect of surface treatment and filler loading on mechanical properties of the composites were studied. the results showed that the modulus of both tensile and flexural increased with increasing filler contents whereas the strength decreased. this was overcome by treating the sawdust fillers with 10% sodium hydroxide (naoh). the tensile, flexural, hardness and water absorption tests showed that the alkali treatment has enhanced the adhesion between the sawdust and the upr matrix. sanaa,(2010) [13] studied the effects of different volumetric fractions from sawdust and short chopped fibers on the mechanical properties of unsaturated polyester composite then these results were compared with the properties of sawdust –fiber filled composites immersed for different periods in a salt solution of (2 n) . wood volume fractions {(20, 30, 50) vf %} selected to be added for un saturated polyester were studied which gave improvement in their selected studied mechanical properties for all reinforced composites (only impact is decreased) and particularly at higher values of volume fractions, were hardness showed an improvement by (15%), compressive strength gave obvious improvement by (38%), while impact resistance decreased by (16%) with the reinforcement of (50 vf %) sawdust. the above values were reduced when the items were immersed in a salt solution for (60days). ahmed & harith ,(2011)[14] studied the mechanical properties were studied including flexural strength and young's modulus for composite materials were prepared using unsaturated polyester resin as binder with two types of fillers (sawdust and chopped reeds) at normal conditions (n.c). the commercial wood, upe and its composite samples were immersed in water for about 30 days to find the weight gain (mt %) of water for the samples, also to find the effect of water on their flexural strength and young's modulus. the results showed that the samples of upe / chopped reeds composite gained highest values of flexural strength (24.5 mpa) and young's modulus (5.1 gpa) as compared with other composites . the wet samples of sawdust composite have lowest values of weight gain (mt %) of water (0.043%) as compared with other composites after immersion. also it’s showed a slight decrease in values of young's modulus and flexural strength except for the composite material formed from upe / chopped reeds which showed an increase in the value of flexural strength for all the samples after immersion where the wet samples of upe / chopped reeds composite gained (29 mpa) as compared with the samples at (n.c). the objectives of this study were preparation of composites materials from natural low cost material sawdust (s.d) and unsaturated polyester by different particle size of sawdust with different percentage and show that which percentages are the best then studying the mechanical properties such as hardness of the composites material & absorption of the composites to water. effect of particle size of sawdust on behaviour of sawdust/upe composites in water 62 ijcpe vol.16 no.4 (dec. 2015) -available online at: www.iasj.net experimental work 1materials unsaturated polyester resin, (source china), (0.5%) of cobalt naphthenate as accelerator and (2%) of methyl ethyl ketone peroxide (mekp) as hardener. two particles size of sawdust (s.d) are used (1.2μm) and (2.3μm) .these particles are obtained by using standard sieves have different sizes. figure (1) shows the sawdust filler. 2composites preparation the sawdust (s.d) filler were passed to heat treatment in an oven shows at 80 o c for 24 h until the weight of the sawdust was constant. it was necessary to remove the residual moisture in the sawdust, which could greatly affect the mechanical properties of the composites [15]. the composites were prepared from unsaturated polyester resin (as a matrix) and added sawdust to cap by molding method which can be summarized by the following steps:  determine the weight of sawdust by using a digital balance.  weigh the weight of resin and its hardener and mix them carefully.  mix the content thoroughly in a clean container by a fan type stirrer before casting it as sheets by using aluminum mold.  leave the composite at room temperature about 24 hours to take time to solidify such as shown in figure (2). 3mechanical test the mechanical test applied to the samples is hardness test by using (quality test device) for polymers type (sore-d). 4water absorption the test samples of polyester resin and its composites were immersed in distilled water for (30 days), the immersion test was performed under ambient temperature. the samples removed from water every 72 hours and weighted by using digital balance. (type: sartorius, h51, made in germany). the weight gain percentage (mt %) was calculated by using the following equation [16]. water absorption: ( ) ... (1) where (mo) is the weight of the samples before soaking in water and (mt) is the weight after soaking in water for a time period (t). results and discussion 1hardness (shore d) figure (3) shows hardness (shore d) for different weight percentage of sawdust for upe/sawdust composites from this figure it can be shown that the hardness of (1.2 μm) particle size of sawdust is higher than the hardness of (2.3 μm) particle size of sawdust, also it was showed that a drop (1.2μm) particle size the (15%) weight percentage of sawdust composites because of the large particle size may cause porosity which cause weakness in the composite. but for (2.3μm) particle size at (10%) weight percentage the hardness is the best. figure (4) shows the relationship of hardness (shore d) of the composites samples with weight percentage of sawdust after immersion in water for (1.2μm) and (2.3μm) particle size of sawdust it can be seen that the hardness of the samples is decreased after immersion of water except the hardness of the sample which has (15%) percentage of (1.2μm) particle size of sawdust was increased because the water may penetrate to the porosity in the specimen that cause a flotation nisreen s. ali and besma m. fahad -available online at: www.iasj.net ijcpe vol.16 no.4 (dec. 2015) 63 of sawdust to the surface and make higher hardness and this agreement with sana [13] . pure sample of (upe) the hardness was decreased by 4.5% after immersion of water. many of the polymers used in composites including upe take some percentage of water if they are immersed in it for some time. 2effect of water the unsaturated polyester upe and upe/sawdust composites samples were immersed in water about (30 days) to find the effect of water on their weight gain. weight gain (mt %) of the samples have been calculate from equation (1).figures (5) and (6) show the change of weight gain which represents by absorption percentage of water with time of immersion. upe resin sample has absorption of water less than its composites samples (for each value of particle size of sawdust). figure (5) shows the absorption percentage of water with time of immersion for upe/sawdust composites for (1.2 μm) particle size of sawdust and different weight percentage it can be shown that composite which have (15%) weight of sawdust have been absorption of water higher than other weight percentage. but for (2.3 μm) particle size of sawdust the (20 %) weight percentage of sawdust have been largest values of absorption of water which represented in figure (6). in addition, the absorption of water for composite samples which have (2.3 μm) particle size of sawdust have been higher than (1.2 μm) particle size of sawdust and this agreement with ahmed & harith [14]. (a) (b) fig. 1, (a) 2.3μm particle size of sawdust. (b) 1.2μm particle size of sawdust. fig. 2, composite sample (uep+s.d) after preparation effect of particle size of sawdust on behaviour of sawdust/upe composites in water 64 ijcpe vol.16 no.4 (dec. 2015) -available online at: www.iasj.net fig. 3, effect of weight percentage of sawdust on hardness of composites fig. 4, effect of weight percentage of sawdust on hardness of composites after immersion fig. 5, effect of time immersion on weight gain for (1.2 μm) particle size composites fig. 6, effect of time immersion on weight gain for (2.3 μm) particle size composites conclusions the main conclusions of this work can be summarized as follows: 1this work shows that successful fabrication of natural fillers filled polyester composites with different particle size and weight percentage of sawdust fillers using molding method. 2the sawdust composites have particle size (1.2 μm) show better behavior in hardness (shore d) test. 3adding the sawdust fillers in different weight percentage for two sizes and (15 %) weight percentage of sawdust of (1.2 μm) highest value of hardness compared with other percentages. 4the composite of (2.3 μm) the (10%) weight percentage of sawdust has highest value of hardness. 5the upe and its composite samples have relatively increased values of weight gain (mt %) after immersion in water. 6the composite samples of (2.3 μm) particle size have relatively highest value of weight gain (mt %) of water than samples of (1.2 μm) particle size. nisreen s. ali and besma m. fahad -available online at: www.iasj.net ijcpe vol.16 no.4 (dec. 2015) 65 7the upe and its composite samples have decrease in the values of the hardness after immersion in water. references 1b. d. agarwal & l. j. broutman "analysis and performance of fiber composites", by john wiley and sons inc,new york, (1980). 2o. w. siebert," polym. plast. technol". eng, 20(2), 133-146, (1983). 3h. f. mark, n. m. bekales & c. g. overberger "encyclopedia of polymer science and engineering" vol. 12, pp256-269, wiley-inter science new york, (1987). 4h. v. boeing, "unsaturated polyesters,structure and properties", by elsevier publishing company, amesterdam, (1964). 5d. h. gittelman, polym. plast. technol. eng, 8(1), 35-62, (1977). 6j. markarian, “additive developments aid growth in woodplastic composites”, plastics, additives and compounding, 4, pp. 18-21, (2002). 7g. pritchard, “two technologies merge: wood-plastic composites”, plastics, additives and compounding, 6, pp.18-21, (2004). 8l. a. pothan, t. sabu, and n. r neelakantan, “short banana fiber reinforced polyester composites: mechanical, failure and aging characteristics”, journal of reinforced plastics and composites, 16(8), pp. 744-765, (1997). 9s. mishra, a.k. mohanty, l.t. drzal, m. misra, s. parija, s.k. nayak, and s.s. tripathy, (2003)."studies on mechanical performance of biofibre/glass reinforced polyester hybrid composite ", compos. sci. technol., 63: 1377– 1385. mechanical characterization of ecs glass fiber 549 downloaded from http://jtc.sagepub.com by on november 30, (2009). 10l. a. pothana, z. oommenb and s. thomas, “dynamic mechanical analysis of banana fiber reinforced polyester composites”, composites science and technology, 63(2), pp. 283-293, (2003). 11a. r. ahmed,”study of the physical unsaturated polyester resin reinforced naturally as industrial replacement”, m.sc.thesis, college of education, tikrit university, (2004). 12z. mosadeghzad, i. ahmad, r. daika , a. ramlib and z. jalaludin, " preparation and properties of acacia sawdust/upr composite based on recycled pet" malaysian polymer journal, vol 4, no.1, p 3041, 2009. 13sanaa a. a. hafad," studying some of mechanical properties (sawdust/unsaturated polyester) composite in salt solution" eng.& tech. journal ,vol.28,no.16,2010. 14ahmed.j. farhan and harith.i. jaffer," effect of water on some mechanical properties for sawdust and chopped reeds /upe composites"baghdad science journal ,vol.6(2),2011. 15n. sombatsompop, and k. chaochanchaikul, "effect of moisture content on mechanical properties", thermal and structural stability, and extrudate texture of pvc/wood sawdust composites, polymer. inter., 53: 1210–1218 (2004) 16c. a. harper," handbook of plastics and elastomers", mcgrawhill book company, (1975). available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.23 no.3 (september 2022) 59 – 66 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: firdews shakir , email: esraa77_esraa77@yahoo.com, name: hussein q hussein, email: husseinqassab@coeng.uobaghdad.edu.iq, name: zeinab t abdulwahhab, email: zainabzozozo@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. upgrading of sharqy baghdad heavy oil via n-hexane solvent firdews shakir a , hussein q hussein b and zeinab t abdulwahhab c a state company for steel industries, ministry of industry and minerals, baghdad, iraq. b chemical engineering department, college of engineering, university of baghdad, baghdad, iraq. c petroleum research and development center, ministry of oil, baghdad, iraq. abstract asphaltenes are a solubility class described as a component of crude oil with undesired characteristics. in this study, sharqy baghdad heavy oil upgrading was achieved utilizing the solvent deasphalting approach as asphaltenes are insoluble in paraffinic solvents; they may be removed from heavy crude oil by adding n-hexane as a solvent to create deasphalted oil (dao)of higher quality. this method is known as solvent de-asphalting (sda). different effects have been assessed for the sda process, such as solvent to oil ratio (4-16/1 ml/g), the extraction temperature (23 ºc) room temperature and (68 ºc) reflux temperature at (0.5 h mixing time with 400 rpm mixing speed). the best solvent deasphalting results were obtained at room temperature and 12 ml/g solvents to oil ratio. as a result, the api of dao was increased by 9.3º compared to the api of sharqy baghdad heavy oil. the asphaltene reduction was 61.56%. the sulfur removal was 32.8%, the vanadium removal was 36.48%, and the nickel removal was 46.21%. keywords: upgrading, deaspdalted oil, asphaltene, solvent deasphalting, and n-hexane. received on 04/06/2022, accepted on 27/07/2022, published on 30/09/2022 https://doi.org/10.31699/ijcpe.2022.3.8 1introduction crude oil refers to a broad range of non-uniform substances that are naturally found. crude oil is a combination of different hydrocarbons with varied structures and degrees of saturation and a variety of contaminants that may be present. the structure of the hydrocarbons included in crude oil influences the bulk characteristics of the oil, most significantly its viscosity and density[1]. oil is classified according to its api scale; api gravity less than 10° is generally considered a bitumen; api gravity between 10° and 22.3° is regarded as heavy oil; api gravity between 22.3° and 31.1° is considered medium oil, and api gravity greater than 31.1° is regarded as light oil[2]. nearly 70% of the world's oil reserves are heavy oil, extra-heavy oil, and bitumen[3]. heavy oil and extra heavy oil are defined as any liquid petroleum that is complex, has a high viscosity, a dark colour, is highly dense, has a high molecular weight, has a large proportion of asphaltene (>15% by mass) and resins (>40% by mass). additionally, this liquid petroleum contains metals such as (ni, v, fe) as well as heteroatoms such as (n, o, s)[4][5]. by definition, crude oil contains a mixture of dissolved gases, liquids, and solids. saturates, aromatics and resins are types of liquids. additionally, many types of solids may be included in crude oil; generally, the most common is solid asphaltene[6]. asphaltene is the most aromatic of crude oil's heaviest components and has the highest molecular weight[7][8]. asphaltene is a crude oil fraction that is insoluble in nalkanes but soluble in aromatic solvents (for example, toluene or benzene)[9]. asphaltene is a black, friable solid that forms when the pressure, temperature, and composition of the oil vary, causing it to deposit. pipelines, heat exchangers, and the bottoms of distillation columns are susceptible to asphaltene precipitation, resulting in decreased efficiency and increased production costs; aggregates of asphaltene are undesirable because they block pipelines, accumulate in storage tanks, and deactivate catalysts [10]. the need to upgrade heavy oil into cleaner and more valuable light oil is increasing continuously in order to sustain future fuel needs. however, heavy oils and bitumen properties include high viscosity/low fluidity, high density/low api gravity, high asphaltenes, sulfur, and metal. therefore, the objectives of upgrading are 1) to reduce the viscosity to aid production and pipeline transportation without diluents addition and 2) to produce synthetic crude oil that meets the qualities of refinery feedstock[11]. furthermore, the profitability of upgrading heavy crude oil/bitumen is further dependent on market value[12]. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:esraa77_esraa77@yahoo.com mailto:husseinqassab@coeng.uobaghdad.edu.iq mailto:zainabzozozo@yahoo.com http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2022.3.8 firdews shakir et al. / iraqi journal of chemical and petroleum engineering 23,3 (2022) 59 66 60 over the years, various technologies for upgrading heavy oil have been developed. however, these technologies have mostly been based on hydrogen addition and carbon rejection with or without catalysts[13]. the solvent deasphalting process (sda), based on liquid-liquid extraction via contact with a paraffinic solvent, is one of the most effective methods for reducing the asphaltene content of heavy oil[14]. solvent deasphalting occurs when a light hydrocarbon solvent is added to the feed material. dao is the improved product, whereas asphalt is the carbon rejection product[15]. the use of solvent deasphalting to upgrade heavy, highly viscous crude oil and natural bitumen improves the properties[16]. the sda process is cost-effective for removing concentrated asphaltene or pitch from heavy oil(ho) and extra heavy oil(eho). therefore, it is suitable for extracting large amounts of high-quality oil that can be improved [17]. sda's operating expenses are also cheap since they are used at relatively low pressure and temperature. in addition, the process is simple to design and scale up, and it is considered a feasible solution since the recovery and recycling of solvents may decrease operating costs[18]. the research group firdews et al. [19] upgraded sharky baghdad heavy crude oil with 22 api and asphaltene content of 3.382 wt.% by using a solvent deasphalting process with n-pentane as a solvent. the api was enhanced to 32 while the asphaltene content decreased to 1.065 wt. % . hussain et al.[20] enhanced sharqy baghdad heavy crude oil with an api of 22 by solvent extraction process using iraqi light naphtha solvent, api of dao increased to 30. radhi [21] used sharqy baghdad heavy crude oil (reduce crude oil, 9.6 api, 23wt. % asphaltene content,90 ppm v,35.2 ppm ni content) using n-hexane as a deasphalting solvent in liquid-liquid extraction, the api gravity of deasphalted oil increased by 20 degrees compared to reduced crude oil, while the asphaltenes content reduced by 78% and the vanadium and nickel metals concentration decreased by 78% and 76%, respectively. this study aims to upgrade sharqy baghdad heavy crude oil using n-hexane by solvent deasphalting process and study the effect of different operating conditions on the characteristics of the produced dao. 2experimental work 2.1. materials a. crude oil the heavy crude oil was supplied from the midland oil company. the crude oil characteristics are listed in table 1. table 1. characteristics of sharqy baghdad heavy crude oil property value specific gravity at 15.6 / 15.6 ºc 0.922 api at 15.6 ºc 22 viscosity at 40 ºc , cs 27.927 asphaltene content , wt. % 3.382 sulfur content , wt. % 4 caradson carbon residue , wt. % 8.98 ash content , wt. % 0.0921 vanadium , ppm 64.554 nickle , ppm 27.887 b. hydrocarbon solvent for deasphalting, n-hexane (purity 99%, chemlab/belgium) the low-boiling petroleum solvents were used. 2.2. procedure solvent deasphalting process: the procedure is divided into four stages: mixing, filtration, drying, and solvent recovery, as below the mixing unit for the solvent deasphalting process, which includes a 500 ml 2-neck for mixing crude (20g) was used in all of the experiments with solvent ( nhexane) in the proper solvent/oil ratio(sor) (ml/g) (4/1, 8/1, 10/1, 12/1, and 16/1). the flask was placed on a heated magnetic stirrer set at 400 rpm for a period of time (30 minutes). to limit the solvent losses to a minimum, a vertical condenser, which runs at total reflux, was installed on the upper neck of the mixing flask. the mixing was investigated at room to (68 ºc)reflux temperatures. the schematic diagram of the laboratory mixing setup is depicted in fig. (1), fig. 1. the schematic diagram of the mixing stage unit firdews shakir et al. / iraqi journal of chemical and petroleum engineering 23,3 (2022) 59 66 61 the mixture produced from the mixing unit was sent to the filtration unit, comprised of a filtration flask, buchner funnel, vacuum pump, and trap. through the filtration process, filter paper (chm 2054) was used, and it was wetted in a solvent before use. next, a (25ml) washing solvent (n-hexane) was added to the mixing flask to ensure completing filtration. the filter paper was dried using an electric oven at 80°c and for 20 min to remove the remaining solvent associated with the pitch on the filter paper. then filter paper is weighted to measure the percentage of pitch precipitate in the dried filter paper. finally, the mixture of dao and solvent was introduced to the simple distillation unit to recover solvent from the dao. it consists of a 500 ml distillation flask heated by the heating mantle. a thermometer is located at the top, an efficient condenser is connected from the side, and the solvent is collected in a receiver at the end. the stripped dao is weighted to determine dao yield and the required analyses. 2.3. analytical instruments the deasphalted oil (dao) was analyzed by different measurement devices such as asphaltene measurement (ip 143 method) (apd-600a), api gravity measurement (astm 4025) using a digital anton paar, sulfur content measurement (astm d7039) (sindie otg), and metal content measurement (analytik jena novaa 350-flame). 3results and discussion 3.1. effect of solvent to oil ratio (sor) experiments were done using n-hexane solvent at room temperature (23 ℃) with sor (4-16 ml/g), mixing time of 0.5 hours, and mixing speed of 400 rpm. the impact of the sor on the api, asphaltene content, precipitated pitch, sulfur content, and metal content (vanadium and nickel) of dao is explained below. a. api gravity the effect of solvent to oil ratio on api of dao at room temperature with sor (4-16 ml/g) and a mixing duration of 0.5 hours is investigated. fig. 2 displays the result. according to the findings, increasing the ratio of solvent to oil resulted in an improvement in the api of dao. with an increase in sor from 4 to 12 ml/g, the api increase sharply, but it increases slightly with sor of 16 ml/g. at sor 16 ml/ g, the higher api obtained was 31.5, which improved by 9.5º. the enhancement of api comes about as a result of rising the solvent power and selectivity for asphaltene removal with increasing sor, the dissolution of asphaltene agglomerates and the decrease in the presence of micelle-like clusters were essential steps in the process of improving the api of heavy crude oil and, subsequently, reaching a stable state at a steady state at 16 ml/g sor. this was consistent with the findings of [19] [20][21]. fig. 2. the effect of solvent to oil ratio on dao api at room temperature and 0.5 h. mixing time b. asphaltene content and pitch precipitate the solvent to oil ratio affects the asphaltene concentration of dao, and the pitch precipitated at room temperature, as shown in fig. 3 (a, b). according to the results, increasing the solvent to oil ratio (4-12 ml/g) resulted in a significant decrease in asphaltene concentration and an increase in pitch precipitate. furthermore, an increase in sor from (4-12 ml/g) resulted in a significant drop in asphaltene content, while a slight decrease at sor (16 ml: 1 g). at (16ml/g)sor, the higher asphaltene content in dao was 1.2631 wt. %, with a removal percentage of 62.65 %, and the higher pitch precipitated to 10.2 wt.% the increasing solvent to oil ratio results in an increase in the degradation of asphaltene molecules with increasing solvent added, which could lead to the creation of activated centres on both the remaining asphaltenes and the freed sheets, thus leading to increase an overall reduction in the average number of layer and increased pitch precipitate. as a result, the dao quality improved. these are agreed with the results reported by[19] [22][23][24]. (a) firdews shakir et al. / iraqi journal of chemical and petroleum engineering 23,3 (2022) 59 66 62 (b) fig. 3. the effect of solvent to oil ratio on (a) asphaltene content and (b) pitch precipitate at room temperature and 0.5 h. mixing time c. sulfur and metals content at room temperature, the effect of the solvent-to-oil ratio on the sulfur and metals (vanadium and nickel) content of dao is being studied. fig. 4 (a-c) results according to the findings of the tests, raising the sor significantly decreased the amount of sulfur and metals in dao. increased sor (4-12 ml/ g) led to a significant drop in sulfur with metals concentration, while sor (16 ml/ g) led to a minor decrease. at sor (16 ml/g), dao had the highest sulfur content (wt. %) of 2.65 and the highest removal rate of 33.75 %. there were 40.70 ppm of vanadium and 14.54 ppm of nickel in dao following the removal of 36.95 and 47.87 %, respectively. the drop in sulfur and metal content in dao is directly proportional to asphaltene concentration. as the asphaltene content of dao decreased, so were the concentrations of sulfur and metals. this agreement is comparable to the results confirmed by [20] [23]. (a) (b) (c) fig. 4. the effect of solvent to oil ratio on (a) sulfur, (b) vanadium, and (c) nickel content of dao at room temperature and 0.5 h. mixing time 3.2 effect of temperature the studies were done at (23 ºc) room temperature and (68 ºc) reflux temperatures with sor (4-16 ml/g), mixing time of 0.5 h and 400 rpm mixing speed. by using nhexane as solvent, the effect of temperature on the dao characteristics: api, asphaltene content and precipitated pitch, sulfur content, and metal content (vanadium and nickel) is detailed below. a. api gravity the effect of changing temperature from (23 ºc) room temperature to 68 ºc on dao api is being investigated. fig. 5 illustrates the result. the research indicated that when the temperature is raised from room temperature to 68 ° c, the api of dao decreases by all sor. the higher api values of dao at (16 ml/g) sor fall from 31.5 to 31 and reduce the improvement degree from 9.5º to 9º at room temperature and 68 ºc, respectively. the api of dao falls when the temperature is raised due to lower asphaltene removal. firdews shakir et al. / iraqi journal of chemical and petroleum engineering 23,3 (2022) 59 66 63 this is because the solubility of asphaltene rises with temperature. consequently, more resins separated from asphaltene molecules, influencing the api of the oil phase. this is in accordance with[19] [23][25]. fig. 5. effect of temperature on dao api using nhexane at (4-16 ml/g) sor and 0.5 h, mixing time b. asphaltene content and pitch precipitate fig. 6 (a, b) represented the influence of changing temperature from room temperature to 68 ºc on the asphaltene content of dao and precipitated pitch is being evaluated. the results indicate that the asphaltene content of dao increases when the temperature is increased from room temperature to 68 ºc for all sor. at (16 ml/g)sor, the higher asphaltene content in dao were 1.2631 wt. % and 1.2954 wt. %, with a percentage removal of 62.65% and 61.697% at room temperature and 68 ºc, respectively. while the higher pitch precipitate was 10.2 and 9.5 wt. % at room temperature and 68 ºc, respectively. when the temperature increases, the asphaltene removal is reduced, and its concentration in dao increases. as the temperature rises, the oil's solubility increases, enabling asphaltenes and resinous compounds to escape into the oil phase. the pitch precipitation reduced as the temperature increased, consistent with previous observations[23][25]. (a) (b) fig. 6. effect of temperature on(a) asphaltene content and (b)pitch precipitate by using n-hexane at (4-16 ml/g) sor and 0.5 h, mixing time c. sulfur and metals content the sulfur and metals (vanadium and nickle) content of dao are being studied in relation to temperature. the results were in fig. 7 (a-c). the sulfur and metals content of dao increases when the temperature increases from room temperature to 68 ºc. at room temperature and ( 16ml/g )sor, the higher sulfur content of dao was 2.65 wt. % with percentage removal was 33.75 %, vanadium content in dao was 40.7 ppm with removal percentage was 36.95%. the nickle content in dao was 14.56 ppm, and their removal percentage was 47.789%. in contrast, at 68 ºc, the higher sulfur content was increased to 2.711 wt. % and lowered their reduction percentage to 32.225 %. the vanadium content in dao was 46.5 ppm; their removed percentage was lowered to 27.967%. the nickle content in dao was 17 ppm, with a removal percentage was 39%. as the temperature increased, the sulfur and metal content of dao increased. this is consistent with the direct relationship between sulfur and metals with asphaltene content being dissolved in dao; rising temperatures increase the amount of asphaltene in the dao. this agrees with the literature results by [23][25]. (a) firdews shakir et al. / iraqi journal of chemical and petroleum engineering 23,3 (2022) 59 66 64 (b) (c) fig. 7. effect of temperature on (a) sulfur, (b)vanadium, and (c) nickel content by using n-hexane at (4-16 ml/g) sor and 0.5 h. mixing time 4conclusion the deasphalting process is considered an efficient method to upgrade heavy crude oil depending on asphaltene removal. it favours low temperatures (room temperature), resulting in the highest upgraded characteristics of dao. increases in the sor (4–16 ml/g) increased the api of dao, precipitated pitch, and decreased the asphaltene content, sulfur, and metals (vanadium and nickel) content, and sor of 12 ml/g is considered the best. dao's api was enhanced by 9.3º, 61.56 % was the reduction of asphaltene. there was a 32.8 % reduction in sulfur, a 36.48% reduction in vanadium, and a 46.21% reduction in nickel removal. references [1] i. c. a. berman, “designing a system for upgrading of heavy crude oils through electron beam treatment,” doctoral dissertation,texas a&m university, 2015. [2] s. m. awadh and h. al-mimar, “statistical analysis of the relations between api, specific gravity and sulfur content in the universal crude oil,” int. j. sci. res., vol. 4, no. 5, pp. 1279–1284, 2015. [3] a. ajumobi, “a study on the heavy crude oil viscosity reduction with the dissolution of nitrogen and carbon dioxide,” cuny academic works, 2015. [4] j. m. lee et al., “separation of solvent and deasphalted oil for solvent deasphalting process,” fuel process. technol., vol. 119, pp. 204–210, 2014, doi: 10.1016/j.fuproc.2013.11.014. [5] o. e. medina, c. olmos, s. h. lopera, f. b. cortés, and c. a. franco, “nanotechnology applied to thermal enhanced oil recovery processes: a review,” energies, vol. 12, no. 24, pp. 1–36, 2019, doi: 10.3390/en12244671. [6] s. fakher, m. ahdaya, m. elturki, and a. imqam, “critical review of asphaltene properties and factors impacting its stability in crude oil,” j. pet. explor. prod. technol., vol. 10, no. 3, pp. 1183–1200, 2020, doi: 10.1007/s13202-019-00811-5. [7] s. bearsley, a. forbes, and r. g. haverkamp, “direct observation of the asphaltene structure in pavinggrade bitumen using confocal laser-scanning microscopy,” j. microsc., vol. 215, pp. 149–155, 2004, doi: 10.1111/j.0022-2720.2004.01373.x. [8] o. c. mullins, “the asphaltenes,” annu. rev. anal. chem., vol. 4, no. july 2011, pp. 393–418, 2011, doi: 10.1146/annurev-anchem-061010-113849. [9] j. f. r. yanes, f. x. feitosa, f. r. do carmo, and h. b. de sant’ana, “paraffin effects on the stability and precipitation of crude oil asphaltenes: experimental onset determination and phase behavior approach,” fluid phase equilib., vol. 474, pp. 116–125, 2018, doi: 10.1016/j.fluid.2018.07.017. [10] x. sun, “molecular simulations on the colloidal behaviors of model asphaltenes,” doctoral dissertation ,university of alberta, 2021. [11] a. hart, g. leeke, m. greaves, and j. wood, “down-hole heavy crude oil upgrading by capri: effect of hydrogen and methane gases upon upgrading and coke formation,” fuel, vol. 119, pp. 226–235, mar. 2014, doi: 10.1016/j.fuel.2013.11.048. [12] c. leyva, m. s. rana, f. trejo, and j. ancheyta, “on the use of acid-base-supported catalysts for hydroprocessing of heavy petroleum,” ind. eng. chem. res., vol. 46, no. 23, pp. 7448–7466, nov. 2007, doi: 10.1021/ie070128q. [13] v. a. balaghi, “partial upgrading of oilsands bitumen and heavy oil: kinetic modeling and reactor design,” master's thesis, university of calgary, 2019. [14] m. sattarin, h. modarresi, h. talachi, and m. teymori, “solvent deasphalting of vacuum residue in a bench-scale unit,” pet. coal, vol. 48, no. 3, pp. 14– 19, 2006, [online]. available: scale_unit/file/9fcfd513ddacff00a5.pdf. [15] a. zachariah and a. de klerk, “partial upgrading of bitumen: impact of solvent deasphalting and visbreaking sequence,” energy and fuels, vol. 31, no. 9, pp. 9374–9380, 2017, doi: 10.1021/acs.energyfuels.7b02004. https://oaktrust.library.tamu.edu/handle/1969.1/174211 https://oaktrust.library.tamu.edu/handle/1969.1/174211 https://oaktrust.library.tamu.edu/handle/1969.1/174211 https://oaktrust.library.tamu.edu/handle/1969.1/174211 https://www.researchgate.net/profile/salih-awadh/publication/305280254_statistical_analysis_of_the_relations_between_api_specific_gravity_and_sulfur_content_in_the_universal_crude_oil/links/582d704708ae138f1c001298/statistical-analysis-of-the-relations-between-api-specific-gravity-and-sulfur-content-in-the-universal-crude-oil.pdf https://www.researchgate.net/profile/salih-awadh/publication/305280254_statistical_analysis_of_the_relations_between_api_specific_gravity_and_sulfur_content_in_the_universal_crude_oil/links/582d704708ae138f1c001298/statistical-analysis-of-the-relations-between-api-specific-gravity-and-sulfur-content-in-the-universal-crude-oil.pdf https://www.researchgate.net/profile/salih-awadh/publication/305280254_statistical_analysis_of_the_relations_between_api_specific_gravity_and_sulfur_content_in_the_universal_crude_oil/links/582d704708ae138f1c001298/statistical-analysis-of-the-relations-between-api-specific-gravity-and-sulfur-content-in-the-universal-crude-oil.pdf https://www.researchgate.net/profile/salih-awadh/publication/305280254_statistical_analysis_of_the_relations_between_api_specific_gravity_and_sulfur_content_in_the_universal_crude_oil/links/582d704708ae138f1c001298/statistical-analysis-of-the-relations-between-api-specific-gravity-and-sulfur-content-in-the-universal-crude-oil.pdf https://academicworks.cuny.edu/cc_etds_theses/343/ https://academicworks.cuny.edu/cc_etds_theses/343/ https://academicworks.cuny.edu/cc_etds_theses/343/ https://www.sciencedirect.com/science/article/pii/s0378382013003664 https://www.sciencedirect.com/science/article/pii/s0378382013003664 https://www.sciencedirect.com/science/article/pii/s0378382013003664 https://www.sciencedirect.com/science/article/pii/s0378382013003664 https://www.mdpi.com/591360 https://www.mdpi.com/591360 https://www.mdpi.com/591360 https://www.mdpi.com/591360 https://www.mdpi.com/591360 https://link.springer.com/article/10.1007/s13202-019-00811-5 https://link.springer.com/article/10.1007/s13202-019-00811-5 https://link.springer.com/article/10.1007/s13202-019-00811-5 https://link.springer.com/article/10.1007/s13202-019-00811-5 https://link.springer.com/article/10.1007/s13202-019-00811-5 https://onlinelibrary.wiley.com/doi/abs/10.1111/j.0022-2720.2004.01373.x https://onlinelibrary.wiley.com/doi/abs/10.1111/j.0022-2720.2004.01373.x https://onlinelibrary.wiley.com/doi/abs/10.1111/j.0022-2720.2004.01373.x https://onlinelibrary.wiley.com/doi/abs/10.1111/j.0022-2720.2004.01373.x https://onlinelibrary.wiley.com/doi/abs/10.1111/j.0022-2720.2004.01373.x https://www.researchgate.net/profile/oliver-mullins/publication/51234411_the_asphaltenes/links/54ac1df70cf21c47713988e9/the-asphaltenes.pdf?_sg%5b0%5d=started_experiment_milestone&origin=journaldetail https://www.researchgate.net/profile/oliver-mullins/publication/51234411_the_asphaltenes/links/54ac1df70cf21c47713988e9/the-asphaltenes.pdf?_sg%5b0%5d=started_experiment_milestone&origin=journaldetail https://www.researchgate.net/profile/oliver-mullins/publication/51234411_the_asphaltenes/links/54ac1df70cf21c47713988e9/the-asphaltenes.pdf?_sg%5b0%5d=started_experiment_milestone&origin=journaldetail https://www.sciencedirect.com/science/article/pii/s0378381218302814 https://www.sciencedirect.com/science/article/pii/s0378381218302814 https://www.sciencedirect.com/science/article/pii/s0378381218302814 https://www.sciencedirect.com/science/article/pii/s0378381218302814 https://www.sciencedirect.com/science/article/pii/s0378381218302814 https://www.sciencedirect.com/science/article/pii/s0378381218302814 https://era.library.ualberta.ca/items/dc6411a6-360c-4972-9750-b380d8e5a07a https://era.library.ualberta.ca/items/dc6411a6-360c-4972-9750-b380d8e5a07a https://era.library.ualberta.ca/items/dc6411a6-360c-4972-9750-b380d8e5a07a https://www.sciencedirect.com/science/article/pii/s0016236113011198 https://www.sciencedirect.com/science/article/pii/s0016236113011198 https://www.sciencedirect.com/science/article/pii/s0016236113011198 https://www.sciencedirect.com/science/article/pii/s0016236113011198 https://www.sciencedirect.com/science/article/pii/s0016236113011198 https://pubs.acs.org/doi/abs/10.1021/ie070128q https://pubs.acs.org/doi/abs/10.1021/ie070128q https://pubs.acs.org/doi/abs/10.1021/ie070128q https://pubs.acs.org/doi/abs/10.1021/ie070128q https://pubs.acs.org/doi/abs/10.1021/ie070128q https://prism.ucalgary.ca/handle/1880/109939 https://prism.ucalgary.ca/handle/1880/109939 https://prism.ucalgary.ca/handle/1880/109939 https://prism.ucalgary.ca/handle/1880/109939 https://www.researchgate.net/profile/manzar-sattarin/publication/215755703_solvent_deasphalting_of_vacuum_residue_in_a_bench-scale_unit/links/0fcfd513ddacff00a5000000/solvent-deasphalting-of-vacuum-residue-in-a-bench-scale-unit.pdf https://www.researchgate.net/profile/manzar-sattarin/publication/215755703_solvent_deasphalting_of_vacuum_residue_in_a_bench-scale_unit/links/0fcfd513ddacff00a5000000/solvent-deasphalting-of-vacuum-residue-in-a-bench-scale-unit.pdf https://www.researchgate.net/profile/manzar-sattarin/publication/215755703_solvent_deasphalting_of_vacuum_residue_in_a_bench-scale_unit/links/0fcfd513ddacff00a5000000/solvent-deasphalting-of-vacuum-residue-in-a-bench-scale-unit.pdf https://www.researchgate.net/profile/manzar-sattarin/publication/215755703_solvent_deasphalting_of_vacuum_residue_in_a_bench-scale_unit/links/0fcfd513ddacff00a5000000/solvent-deasphalting-of-vacuum-residue-in-a-bench-scale-unit.pdf https://www.researchgate.net/profile/manzar-sattarin/publication/215755703_solvent_deasphalting_of_vacuum_residue_in_a_bench-scale_unit/links/0fcfd513ddacff00a5000000/solvent-deasphalting-of-vacuum-residue-in-a-bench-scale-unit.pdf https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.7b02004 https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.7b02004 https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.7b02004 https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.7b02004 https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.7b02004 firdews shakir et al. / iraqi journal of chemical and petroleum engineering 23,3 (2022) 59 66 65 [16] m. r. gray, upgrading oilsands bitumen and heavy oil. university of alberta, 2015. [17] s. ahn, s. shin, s. i. im, k. b. lee, and n. s. nho, “solvent recovery in solvent deasphalting process for economical vacuum residue upgrading,” korean j. chem. eng., vol. 33, no. 1, pp. 265–270, 2016, doi: 10.1007/s11814-015-0146-3. [18] m. h. zirasefi, f. khorasheh, j. ivakpour, and a. mohammadzadeh, “improvement of the thermal cracking product quality of heavy vacuum residue using solvent deasphalting pretreatment,” energy and fuels, vol. 30, no. 12, pp. 10322–10329, 2016, doi: 10.1021/acs.energyfuels.6b02297. [19] f. shakir, h. q. hussein, and z. t. abdulwahhab, “influence of nanosilica on solvent deasphalting for upgrading iraqi heavy crude oil,” baghdad sci. j., pp. 144–156, 2022, doi: /10.21123/bsj.2022.6895. [20] h. k. hussain, s. m. ali, and y. m. ali, “upgrading sharky baghdad heavy crude oil,” alkhwarizmi eng. j., vol. 7, no. 3, pp. 19–29, 2011. [21] a. j. radhi, “upgrading of east baghdad resid by n-hexane,” higher diploma, university of technology, 2012. [22] s. l. kokal, j. najman, s. g. sayegh, and a. e. george, “measurement and correlation of asphaltene precipitation from heavy oils by gas injection,” j. can. pet. technol., vol. 31, no. 04, 1992, doi: 10.2118/92-04-01. [23] a.-h. a.-k. mohammed and h. k. hussain, “deasphaltening and hydrodesulfurization of basrah vacuum residue”, ijcpe, vol. 2, no. 4, pp. 12–18, dec. 2001. [24] j.-b. b. mougnol, a. rabiu, e. banijesu, and z. sam, “asphaltene extraction capacity of different solvents,” in ieea ’18: proceedings of the 7th international conference on informatics, environment, energy and applications, 2018, pp. 114–118, doi: 10.1145/3208854.3208861. [25] a. s. s. turuga, “effect of solvent deasphalting process on the properties of deasphalted oil and asphaltenes from bitumen,” master thesis, university of alberta, 2017. https://books.google.com/books?hl=en&lr=&id=qp_acqaaqbaj&oi=fnd&pg=pp1&dq=%5b16%5d%09m.+r.+gray,+upgrading+oilsands+bitumen+and+heavy+oil.+university+of+alberta,+2015.&ots=mjypnjwwa9&sig=cg8zodhvqksn8w8ljkqhvn1gj00 https://books.google.com/books?hl=en&lr=&id=qp_acqaaqbaj&oi=fnd&pg=pp1&dq=%5b16%5d%09m.+r.+gray,+upgrading+oilsands+bitumen+and+heavy+oil.+university+of+alberta,+2015.&ots=mjypnjwwa9&sig=cg8zodhvqksn8w8ljkqhvn1gj00 https://link.springer.com/article/10.1007/s11814-015-0146-3 https://link.springer.com/article/10.1007/s11814-015-0146-3 https://link.springer.com/article/10.1007/s11814-015-0146-3 https://link.springer.com/article/10.1007/s11814-015-0146-3 https://link.springer.com/article/10.1007/s11814-015-0146-3 https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.6b02297 https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.6b02297 https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.6b02297 https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.6b02297 https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.6b02297 https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.6b02297 https://bsj.uobaghdad.edu.iq/index.php/bsj/article/view/6895 https://bsj.uobaghdad.edu.iq/index.php/bsj/article/view/6895 https://bsj.uobaghdad.edu.iq/index.php/bsj/article/view/6895 https://bsj.uobaghdad.edu.iq/index.php/bsj/article/view/6895 https://bsj.uobaghdad.edu.iq/index.php/bsj/article/view/6895 https://alkej.uobaghdad.edu.iq/index.php/alkej/article/view/69 https://alkej.uobaghdad.edu.iq/index.php/alkej/article/view/69 https://alkej.uobaghdad.edu.iq/index.php/alkej/article/view/69 https://uotechnology.edu.iq/dep-chem-eng/thesis/hdepl_1/ali_g.pdf https://uotechnology.edu.iq/dep-chem-eng/thesis/hdepl_1/ali_g.pdf https://uotechnology.edu.iq/dep-chem-eng/thesis/hdepl_1/ali_g.pdf https://onepetro.org/jcpt/article/doi/10.2118/92-04-01/31827 https://onepetro.org/jcpt/article/doi/10.2118/92-04-01/31827 https://onepetro.org/jcpt/article/doi/10.2118/92-04-01/31827 https://onepetro.org/jcpt/article/doi/10.2118/92-04-01/31827 https://onepetro.org/jcpt/article/doi/10.2118/92-04-01/31827 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/598 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/598 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/598 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/598 https://dl.acm.org/doi/abs/10.1145/3208854.3208861 https://dl.acm.org/doi/abs/10.1145/3208854.3208861 https://dl.acm.org/doi/abs/10.1145/3208854.3208861 https://dl.acm.org/doi/abs/10.1145/3208854.3208861 https://dl.acm.org/doi/abs/10.1145/3208854.3208861 https://dl.acm.org/doi/abs/10.1145/3208854.3208861 https://era.library.ualberta.ca/items/93866988-34d4-4d7c-8da7-e2ae6a8636db https://era.library.ualberta.ca/items/93866988-34d4-4d7c-8da7-e2ae6a8636db https://era.library.ualberta.ca/items/93866988-34d4-4d7c-8da7-e2ae6a8636db https://era.library.ualberta.ca/items/93866988-34d4-4d7c-8da7-e2ae6a8636db firdews shakir et al. / iraqi journal of chemical and petroleum engineering 23,3 (2022) 59 66 66 تحسين نفط شرقي بغداد الثقيل بواسطة مذيب الهكسان االعتيادي 3،زينب طالب عبد الوهاب2،حسين قاسم حسين1فردوس شاكر ، وزارة الصناعة والمعادن، بغداد ، العراق. الشركة العامة للصناعات الفوالذية 1 قسم الهندسة الكيميائية ، كلية الهندسة ، جامعة بغداد ، بغداد ، العراق. 2 العراق.مركز البحث والتطوير النفطي، وزارة النفط ، بغداد ، 3 الخالصة األسفلتينات تصنف على اساس قابلية الذوبان كمكون من مكونات النفط الخام تتصف بخصائص غير مرغوب فيها. في هذه الدراسة ، تم تحسين نفط شرق بغداد الثقيل باستخدام طريقةازالة األسفلتينات بالمذيبات إزالتها من النفط الخام الثقيل عن طريق حيث أن األسفلتينات غير قابلة للذوبان في المذيبات البرافينية. يمكن ( ذو جودة اعلى. ُتعرف هذه الطريقة daoإضافة مذيب الهكسان االعتيادي للحصول نفط منزوع االسفلتين ) ، مثل نسبة المذيب إلى sda. تم دراسة تأثيرات مختلفة لعملية sdaباسم إزالة األسفلتينات بالمذيبات )) 68درجة مئوية( درجة حرارة الغرفة و) 23درجة حرارة االستخالص وهي ) مل / جم( ، 1/ 16-4النفط ) (. تم الحصول على r.p.m 400ساعة وسرعة خلط 0.5درجة مئوية( درجة حرارة االرتجاع عند )وقت خلط مل / جم نسبة المذيبات إلى النفط. نتيجة 12أفضل نتائج نزع األسفلت بالمذيب عند درجة حرارة الغرفة و ٪. كانت نسبة إزالة الكبريت 61.56. بلغت ازالة األسفلتينات 31.3إلى daoلـ api، تمت تحسين لذلك زالة الفاناديوم 32.8 زالة النيكل 36.48٪ ، وا ٪.46.21٪ ، وا العتيادي.الكلمات الدالة: التحسين ، النفط المنزوع االسفلتين ،األسفلتينات ، عملية إزالة االسفلتين بالمذيبات ، والهكسان ا iraqi journal of chemical and petroleum engineering vol.13 no.3 (september 2012) 916 issn: 1997-4884 development of pvt correlation for iraqi crude oils using artificial neural network nada. s. ahmedzeki *, iqdam. m. ridha, yazan. m. ali, and zainab. t. abidalwahab petroleum research and development centre, baghdad, iraq * university of baghdad, college of engineering, chemical engineering department baghdad, iraq abstract several correlations have been proposed for bubble point pressure, however, the correlations could not predict bubble point pressure accurately over the wide range of operating conditions. this study presents artificial neural network (ann) model for predicting the bubble point pressure especially for oil fields in iraq. the most affecting parameters were used as the input layer to the network. those were reservoir temperature, oil gravity, solution gas-oil ratio and gas relative density. the model was developed using 104 real data points collected from iraqi reservoirs. the data was divided into two groups: the first was used to train the ann model, and the second was used to test the model to evaluate their accuracy and trend stability. trend test was performed to ensure that the developed model would follow the physical laws. results show that the developed model outperforms the published correlations in term of absolute average percent relative error of 6.5%, and correlation coefficient of 96%. introduction reservoir fluid properties are very important in reservoir engineering computations such as material balance calculations, well test analysis, reserve estimates, and numerical reservoir simulations. ideally, these properties should be obtained from actual measurements. quite often, however, these measurements are either not available, because of one or more of these reasons: a) samples collected are not reliable. b) samples have not been taken because of cost saving. c) pvt analyses are not available when needed. this situation often occurs in production test interpretation (1) . in such cases, empirically derived correlations are used to predict the needed properties. all computations, therefore, will depend on the accuracy of the correlations used for predicting the fluid properties (2) . bubble point pressure is defined as the pressure at which the first gas bubble evolves from liquid phase, thus differentiating between single and multi-phase state of reservoir fluids (3) . there are many empirical correlations for predicting pvt properties, most of them were developed using linear or non-linear multiple regression or graphical techniques. each correlation was developed for a certain range of reservoir fluid characteristics and geographical area with similar fluid iraqi journal of chemical and petroleum engineering university of baghdad college of engineering development of pvt correlation for iraqi crude oils using artificial neural network 10 ijcpe vol.13 no.3 (september 2012) -available online at: www.iasj.net compositions and api gravity. thus, the accuracy of such correlations is critical and it is not often known in advance (2) . precise prediction of bubble point pressure (pb) is very important in reservoir and production computation. anns are biologically inspired nonalgorithmic, non-digital, massively parallel distributive and adaptive information processing systems. they resemble the brain in acquiring knowledge through learning process, and storing knowledge in inter-neuron connection strengths (3) . the objective of this study is to develop new predictive models for pb based on artificial neural networks (ann) using field data collected from oil fields in iraq. pvt empirical correlations for the last 60 years, engineers realized the importance of developing and using empirical correlations for pvt properties. studies carried out in this field resulted in the development of new correlations. standing (4,5) in 1947 and 1977 presented correlations for bubble point pressure and for oil formation volume factor. standing’s correlations were based on laboratory experiments carried out on 105 samples from 22 different crude oils in california. glaso (6) (1980) developed correlation for pb using 45 oil samples from north sea hydrocarbon mixtures. al-marhoun (7) (1988) published correlations for estimating bubble point pressure and oil formation volume factor for the middle east oils. he used 160 data sets from 69 middle eastern reservoirs to develop the correlation. dokla and osman (8) (1992) published set of correlations for estimating bubble point pressure and oil formation volume factor for uae crudes. they used 51 data sets to calculate new coefficients for al marhoun (7) middle east models. alyousef and al-marhoun (9) (1993) pointed out that the dokla and osman (8,10) in 1992 and 1993 bubble point pressure correlation was found to contradict the physical laws. macary and el-batanoney (11) (1992) presented correlations for bubble point pressure and oil formation volume factor. they used 90 data sets from 30 independent reservoirs in the gulf of suez to develop the correlations. the new correlations were tested against other egyptian data of saleh et al. (12) (1987) and showed improvement over published correlations. in 1993, petrosky and farshad (13) developed new correlations for gulf of mexico crude oils. standing (4) (1947) correlations for bubble point pressure, solution gas oil ratio, and oil formation volume factor were taken as a basis for developing their new correlation coefficients. ninety data sets from the gulf of mexico were used in developing these correlations. almehaideb (14) (1997) published a new set of correlations for uae crudes using 62 data sets from uae reservoirs. these correlations were developed for bubble point pressure and oil formation volume factor. the bubble point pressure correlation like that of omar and todd (15) (1993) uses the oil formation volume factor as input in addition to oil gravity, gas gravity, solution gas oil ratio, and reservoir temperature. elsharkawy et al. (16) (1994) evaluated pvt correlations for kuwaiti crude oils using 44 samples. standing (4) (1947) correlation gave the best results for bubble point pressure while almarhoun (7) (1988) oil formation volume factor correlation performed satisfactory. finally, al-shammasi (17) (1997) evaluated the published correlations for bubble point pressure and oil formation volume factor for accuracy and flexibility to represent hydrocarbon mixtures from different nada. s. ahmedzeki, iqdam. m. ridha, yazan. m. ali, and zainab. t. abidalwahab -available online at: www.iasj.net ijcpe vol.13 no.3 (september 2012) 11 geographical locations worldwide. he presented a new correlation for bubble point pressure based on global data of 1661 published and 48 unpublished data sets. he concluded that statistical and trend performance analysis showed that some of the correlations violate the physical behavior of hydrocarbon fluid properties. a list of some correlations found in literature is summarized in table (1). table 1, summary of the previous correlations researchers correlations standing (1947) pb=18.2[(rs/γg) 0.83 (10) a -1.4] a=0.00091(t-460)-0.0125(api) glaso (1980) log(pb)=1.7669+1.7447log(pb*)-0.30218[log(pb*)] 2 pb*=(rs/γg) 0.816 (t) 0.172 (api) -0.989 al-marhoun (1988) pb=5.338088*10 -3 rs 0.715082 γg -1.87784 γo 3.1437 t 1.32657 dokla and osman (1992) pb=0.836386*10 4 γg -1.01049 γo 0.107991 t -0.952584 rs 0.724047 petrosky and farshad (1993) pb=[112.727rs 0.577421 /γg 0.8439 (10) x ] – 1391.051 x=7.916(10 -4 )(api) 1.5410 – 4.561 (10 -5 )(t-460) 1.3911 pvt neural network models artificial neural networks are paralleldistributed information processing models that can recognize highly complex patterns within available data. in recent years, neural network have gained popularity in petroleum applications. many authors discussed the applications of neural network in petroleum engineering. few studies were carried out to model pvt properties using neural networks (2) . in 1996, gharbi and elsharkawy (18) published neural network models for estimating bubble point pressure and oil formation volume factor for middle east crude oils. they used two hidden layers neural networks to model each property separately. the bubble point pressure model had eight neurons in the first layer and four neurons in the second. the formation volume factor model had six neurons in both layers. both models were trained using 498 data sets collected from the literature and unpublished sources. the models were tested by other 22 data points from the middle east. the results showed improvement over the conventional correlation methods with reduction in the average error for the bubble point pressure oil formation volume factor. gharbi and elsharkawy (19) (1997) presented another neural network model for estimating bubble point pressure and oil formation volume factor for universal use. they used three-layer neural network model to predict the two properties. they developed the model using 5200 data sets collected from all over the world representing 350 different crude oils. another set of data consisting of 234 data sets was used for verifying the results of the model. the reported results for the universal model showed less improvement than the middle east neural model over the conventional correlations. the bubble point pressure average error was lower than that of the conventional correlations for both training and test data. finally, varotsis et al. (20) (1999) presented a novel approach for predicting the complete pvt behavior of reservoir oils and gas condensates using artificial neural network (ann). the method uses key measurements that can be performed rapidly either in the lab or at the well development of pvt correlation for iraqi crude oils using artificial neural network 12 ijcpe vol.13 no.3 (september 2012) -available online at: www.iasj.net site as input to an ann. the ann was trained by a pvt studies database of over 650 reservoir fluids originating from all parts of the world. tests of the trained ann architecture utilizing a validation set of pvt studies indicate that, for all fluid types, most pvt property estimates can be obtained with a very low error which is considered better than that provided by tuned equation of state (eos) models, which are currently in common use for the estimation of reservoir fluid properties. in addition to improved accuracy, the proposed ann architecture avoids the ambiguity and numerical difficulties inherent to eos models and provides for continuous improvements by the enrichment of the ann training database with additional data. data acquisition data set used to implement the ann model was obtained from experimental work and fields testing, this data set consists of 104 observations collected from iraqi oil fields. each data set contains the following data observations: (1) reservoir temperature (t), (2) oil gravity (γo), (3) solution gas-oil ratio (rs), (4) gas relative density (γg), (5) bubble point pressure (pb). development of ann based correlation database generation collecting data is the preliminary step for building ann. bubble point pressure values were collected from many iraqi crude oils as aforementioned. selected parameters affecting the bubble point pressure, which is the target of this simulation, were investigated via literature survey. these parameters were organized into four inputs to be fed to the ann. the range of the input parameters as well as the desired parameter is given in table (2). by examining this table, one can see the wide range and the complex relationship of the input and the output parameters, studied in the present study. building ann with the optimal structure depends mainly on careful planning for the necessary information fed to the network as the input layer. table 2, the range of input and output parameters input parameter range solution gas-oil ratio 183.049 – 1799.9 scf/stb stock tank oil relative density (water=1) 0.815 – 0.9575 gas relative density (air=1) 0.723 – 1.7577 reservoir temperature 510 – 805.5 (r°) output bubble point pressure 550.03 – 4409.369 psia training of artificial neural network training was accomplished using neuro solutions by excel version 5, supplied by neuro dimension, inc. copyright 1997-2005.(mlps) type was used which is multilayered feed forward network, trained with static backpropagation of error. 67% of the collected data was set as training, 33% as testing. it computes the error in a test set at the same time that the network is being trained with the training set. it is known that the error nada. s. ahmedzeki, iqdam. m. ridha, yazan. m. ali, and zainab. t. abidalwahab -available online at: www.iasj.net ijcpe vol.13 no.3 (september 2012) 13 will keep decreasing in the training set, but may start to increase in the test set. this happens when the network starts “memorizing” the network pattern (21) . the use of ann to predict the bubble point pressure was implemented using two kinds of networks. the first ann consists of an input layer with four input pes, corresponding to the four input parameters (stated before); one hidden layer, and output layer of one pes representing the bubble point pressure. the second had the same structure except having two hidden layers. many trials were made to find the best topology of the (mlps). the training process starts with randomly chosen initial weight values. then a back-propagation algorithm is applied after each iteration, the weights are modified so that the cumulative error decreases. in back-propagation, the weight changes are proportional to the negative gradient of error. backpropagation may have an excellent performance; this algorithm is used to calculate the values of the weights and the following procedure is then used (called “supervised learning”) to determine the values of weights of the network: 1. for a given ann architecture, the value of the weights in the network is initialized as small random numbers. 2. the input of the training set is sent to the network and the resulting outputs are calculated. 3. the measurement of the error between the outputs of the network and the known correct (target) values is calculated. 4. the gradients of the objective function with respect to each of the individual weights are calculated. 5. the weights are changed according to the optimization search direction. 6. the procedure returns to step 2. 7. the iteration terminates when the value of the objective function calculated using the data in the test approaches experimental value. the learning process includes the procedure when the data from the input neurons is propagated through the network via the interconnections. each neuron in a layer is connected to every neuron in adjacent layers. a scalar weight is associated with each interconnection. neurons in the hidden layers receive weighted inputs from each of the neurons in the previous layer and they sum the weighted inputs to the neuron and then pass the resulting summation through a nonlinear activation function (hyperbolic tan function) (21, 23) . fig.1, ann structure of present study results and discussions the selection of number of hidden layer neurons ( perceptrons or pes) is very important and troublesome. after training the neural network, with 67% of the randomized data sets (70 data points), the models become ready for testing and evaluation. to perform this, the last data group (34 data points) which was not seen by the neural network during training was used. for the purpose of finding the best architecture of the network, the testing % aare and the correlation coefficient (% r) which should be around unity, are calculated and compared for each topology and for each correlations. therefore, after input layer hidde n output layer γg t rs pb γo development of pvt correlation for iraqi crude oils using artificial neural network 14 ijcpe vol.13 no.3 (september 2012) -available online at: www.iasj.net careful training of the network, testing showed that ann structure of [4-9-1] as shown in fig.(1), using the activation function of (tanh), momentum rate of 0.7 and after 5000 iteration, had correlated the bubble point pressure with reservoir temperature, oil gravity, solution gasoil ratio, and gas relative density, successfully. the result of prediction is plotted with experimental values as shown in figs (2) and (3). fig.2, desired (measured) and actual (predicted) values vs. testing exemplars fig.3, predicted values vs. observed values to ann and previous works table 3, comparison of the present results with previous work correlations aare% r% sx% standing (1947) 22.6 80.8 30.7 glaso (1980) 17.8 81.4 22.5 al-marhoun (1988) 103.7 68 139.2 dokla and osman (1992) 69 77.6 91.7 petrosky and farshad (1993) 36.8 74.3 45.9 ann (present study) 6.5 96 9.3 d es ired o u tp u t an d a c tu al n etwo rk o u tp u t 0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 e x e m p la r o u tp u t pb pb output 0 2000 4000 6000 8000 10000 0 2000 4000 6000 8000 10000 exp. p re d . ann standing glaso marhoun petrosky dokla nada. s. ahmedzeki, iqdam. m. ridha, yazan. m. ali, and zainab. t. abidalwahab -available online at: www.iasj.net ijcpe vol.13 no.3 (september 2012) 15 conclusions 1. a model was developed to predict the bubble point pressure for iraqi crude oils. the model was based on artificial neural network, and developed using 104 data points collected from different iraqi fields. 2. it was concluded that the structure of [4-9-1] was chosen as the best to implement the target of the present study. mlp architecture of four neurons in the first layer which are the four inputs to the network; solution gas –oil ratio, tank oil relative density, gas relative density and reservoir temperature. nine neurons were in the second layer( i.e. hidden layer), and one neuron in the third layer which accounts for the bubble point pressure in the output layer. 3. in addition, the developed pb model outperforms the previous published empirical correlations. also the present study supports the idea of developing local / regional models rather than universal ones. the results show that the developed model provides better prediction and higher accuracy than published empirical correlations, with an average absolute percent relative error of 6.5% and correlation coefficient of 96%. nomenclature pb = bubble point pressure psia rs = solution gas-oil ratio (scf/stb) t = temperature (r°) γo = stock tank oil relative density (water=1) γg = gas relative density (air=1) sx = standard deviation r = correlation coefficient references 1. hemmati m.n., and kharrat r., 2007 " evalution of empirically derived pvt properties for middle east crude oils" scientia iranica, vol. 14,no. 4,pp 358-368. 2. osman, e.a., ahmed o.a., and almarhoun,m.a.,2001 "prediction of oil pvt properties using neural network" paper spe 68233,presented at the 2001 spe middle east oil show and conference, mannama march 17-20. 3. almarhoun m.a., osman e.a. ,2002 " using artificial neural network to develop new pvt correlations for saudi crude oils" paper spe 78592, presented at the 10 th abu dhabi international petroleum exhibition and conference, 13-16 october. 4. standing m.b.,api(1947) "a pressure-volume-temperature correlation for mixture of california oils and gses"drill&pract.,pp275-87. 5. standingm.b.,tx(1977)"volumetri c and phase behavior of oil field hydrocarbon system. millet print inc., dallas. 6. glaso o.,(may 1980) "generalized pressure-volume-temperature correlations" jpt ,785. 7. al-marhoun, m.a., (may 1988) "pvt correlations for middle east crude oils" jpt,650. 8. dokla, m., and osman m., (march 1992) "correlation of pvt properties for uae crudes" spee 41. 9. al-yousef, h. y., al-marhoun, m. a. (march 1993) "discussion of correlation of pvt properties for uae crudes" spee 80. 10. dokla, m., and osman m., (march 1992) "authors' reply to discussion of correlation of pvt properties f or uae crudes" spee 82. 11. macary, s. m. & elbatanoney, m. h., (1992) "derivation of pvt correlations for development of pvt correlation for iraqi crude oils using artificial neural network 16 ijcpe vol.13 no.3 (september 2012) -available online at: www.iasj.net the golf of suez crude oils" paper presented at the egpc 11 th petroleum exploration & production conference, cairo, egypt. 12. saleh, a. m., maggoub, i. s. and asaad, y., (1987) "evaluation of empirically derived pvt properties for egyptian oils" paper spe 15721, presented at the middle east oil show & conference, bahrain, march 7-10. 13. petrosky, j., and farshad, f. (1993) " pressure-volumetemperature correlation for the golf of mexico." paper spe 26644 presented at the spe annual technical conference and exhibition, house, tx, oct 3-6. 14. almehaideb, r.a., (1997) "improved pvt correlations for uae crude oils" paper spe 37691, presented at the spe middle east show & conference, bahrain, march 15-18. 15. omar, m. i. and todd, a.c., (1993) "development of new modified black oil correlation for malaysian cruds" paper spe 25338, presented at the spe asia pacific asia pacific & gas conference and exhibition, singapore , feb 8-10. 16. elsharkawy, a. m., elgibaly a. and alikhan, a. a. (1994) "assessment of the pvt correlations for predicting the properties of the kuwait crude oils" paper presented at the 6 th abu dhabi international petroleum exhibition & conference, oct 1619. 17. al-shammasi , a.a.(1997) "bubble point pressure and oil formation volume factor correlations" paper spe 53185, presented at the spe middle east oil show & conference, bahrain, march 15-18. 18. gharbi, r.b. and elsharkawy, a. m.,(1997)"neural-network model for estimating the pvt properties of middle east crude oils" paper spe 37695, presented at the spe middle east oil show & conference, bahrain, march 15-18. 19. gharbi, r.b. and elsharkawy, a. m.,(1997)"universal neuralnetwork model for estimating the pvt properties of crude oils" paper spe 38099, presented at the spe asia pacific oil & gas conference, kula lumpur, malaysia april 14-16. 20. varotsis n., gaganis v., nighswander j., and guieze p., (1999) "a novel non-iterative method for the prediction of the pvt behavior of reservoir fluids" paper spe 56745, presented at the spe annual technical conference and exhibition, houston,texas, oct 3-6. 21. www.nd.com 22. http://en.wikipedia.org/wiki/art ificial neural network. 23. ahmedzeki n.s. (2007) “ prediction of the heat transfer coefficient in a bubble column using an artificial neural network” ,phd thesis, university of baghdad. http://www.nd.com/ http://en.wikipedia.org/wiki/ iraqi journal of chemical and petroleum engineering vol.17 no.2 (june 2016) 3745 issn: 1997-4884 the effect of asphaltene on the stability of iraqi water in crude oil emulsions sawsan a.m. mohammed and sally d. maan chemical engineering department – college of engineering – university of baghdad abstract in the present work, asphaltenes and resins separated from emulsion samples collected from two iraqi oil wells, nafut kana (nk) and basrah were used to study the emulsion stability. the effect of oil resins to asphaltene (r/a) ratio, ph of the aqueous phase, addition of paraffinic solvent (n-heptane), aromatic solvent (toluene), and blend of both (heptol) in various proportions on the stability of emulsions had been investigated. the conditions of experiments were specified as an agitation speed of 1000 rpm for 30 minutes, heating at 50 °c, and water content of 30%. the results showed that as the r/a ratio increases, the emulsion will be unstable and the amount of water separated from emulsion increases. it was noticed that the emulsion of nk crude oil became more stable at basic ph range, and reached to completely stabilized emulsion at ph=12. whereas basrah emulsion was stable in both acidic and basic ph ranges. results indicated that toluene gave a good solubility for asphaltene, and a higher water separation for both crude oil emulsions. a mathematical model to determine the kinetic constants that characterize the coalescence in the emulsions was also developed. key words: crude oil, w/o emulsion, r/a, asphaltene solvency introduction water is usually present in crude oil reservoirs or injected as steam to stimulate oil production. water and oil can mix while rising through the well and when going through valves and pumps to form in most cases relatively stable dispersions of water droplets in crude oil, which are usually referred to as oil field emulsions. about 80% of exploit crude oils exist in an emulsion state all over the world [1]. waterin oil emulsions are commonly encountered in the petroleum industry, such as in transportation stations dealing with crude oil and natural gas through pipelines and in petroleum refineries. emulsions can cause difficulties in crude oil transportation and storage as well as pipeline corrosion. emulsions are undesirable because the volume of dispersed water occupies space in the pipelines and processing equipments and increases capital and operating costs. moreover, the physical properties and characteristics of oil change significantly upon emulsification. the density of emulsion can increase for the emulsion. iraqi journal of chemical and petroleum engineering university of baghdad college of engineering the effect of asphaltene on the stability of iraqi water in crude oil emulsions 38 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net the most significant change is observed in viscosity, which typically increases [2]. crude oil emulsions contains polar compounds such as asphaltenes and resins that play the role of natural emulsifiers and low molecular weight fatty acids, naphthenic acids in addition to many types of fine solids (clay, crystallized waxes, etc.), therefore, these emulsions can be very stable. these materials help in the formation of resistant films at the crude oil/water interface [3]. asphaltenes are high molecular weight solids which are insoluble in paraffinic solvents and soluble in aromatic solvents such as toluene and benzene [5-7]. resins are soluble in aliphatic hydrocarbons with low molar mass such as n-heptane, and in aromatic solvents such as toluene and benzene and insoluble in ethyl acetate [8]. both asphaltenes and resins correspond to the heavy fraction of crude oil composed of polar molecules. their structure contains heteroatoms such as oxygen, nitrogen, and sulphur, and metals such as vanadium, nickel, and iron. however, asphaltenes have higher molar mass, aromaticity, greater quantity of heteroatoms and metals [8, 9]. asphaltenes are flat sheets of condensed polyaromatic hydrocarbons linked together by ether, sulfide, and aliphatic chain groups. the edges of the sheets are alkyl chains. the polar parts of the asphaltene molecules interact with each other forming micelles or aggregates. as such, these micelles are very much polar. resins are less polar, and made up of smaller molecules with one end being hydrophilic made up of functional groups and the other end hydrophobic made up of alkyl chains. in crude oils, the resins are attached to the asphaltene micelles at the polar end and the non-polar end of the resin interact with crude oil. the resins solvate the asphaltene aggregates and keep them in colloidal suspension in the oil. the aromaticity of the oil also increases the solvency of the asphaltene aggregates. the colloidal aggregates can be interfacially active if the interaction of the asphaltene with the water interface is favored over interaction with resins and aromatics in the crude oil phase. it is proposed that asphaltenes stabilize w/o emulsion if they are near or above the asphaltene precipitation onset point. this is the point at which the asphaltene start to precipitate, caused by addition of an alkane such as n-heptane to the crude oil [10]. adding resins to w/o emulsion containing asphaltenes may reduce, promote, or have no significant effect on the emulsion stability depending on resins to asphaltenes (r/a) ratio and type (polar character). to the best of our knowledge there has been no reported study about the effect of resin to asphaltene ratio (r/a) on the stability of iraqi crude oil emulsions. experimental work materials the present work was carried out on selected two types of crude oil (nk, basrah). the physical properties of these oils are listed in table (1). table 1, physical properties of crude oils property nk crude oil basrah crude oil sp.gr at 15.6 °c 0.8160 0.8702 api 41.9 31.1 asphaltene (%wt) 0.08 2.45 kin.viscosity (cst) at 10 °c 7.2 24.3 sulfur content (%wt) 0.58 2.66 ibp °c 45 39 sawsan a.m. mohammed and sally d. maan -available online at: www.iasj.net ijcpe vol.17 no.2 (june 2016) 39 experimental procedure measurement of the asphaltene and resin content of crude oil 16 g of crude oil (basrah,nk) was weighed and 200 ml of n-pentane was added to the crude oil to precipitate the asphaltene and mixed well using the magnetic stirrer. the crude oil pentane mixture was covered and let to stand for at least 14 hr (normally this is sufficient time for flocculation).the mixture was then filtered using vacuum. the flask was rinsed 2-3 times with 20 ml of pentane solvent each time and filtering was continued at steady rate. the precipitate was washed with fresh solvent until washing are colorless .the precipitate (asphaltene) was dried in an oven at 100 °c over night. the asphaltene was weighed to find the asphaltene content from the following equation: … (1) the n-pentane filtrate containing deasphalted oil (maltene) was collected. the filtrate was concentrated by heating (not higher than 50 °c).the adsorbent (silica gel) was prepared for adsorption work, and mixed well with the deasphalted oil until a viscous mass was formed (18g). the mixture (deasphalted oil +silica gel) was transferred into a soxhelt extractor. (110 ml) n-pentane was added to the round bottom flask. the temperature was maintained at 40°c. extraction was conducted with n-pentane in a soxhlet extractor. extraction was continued by circulating until the liquid exiting the adsorbent bed is colorless (resembles the color of npentane solvent). the less polar materials (saturate and aromatic) are separated from the mixture. the solvent was replaced with chloroform and extracted again at 65 °c. extraction was stopped when the liquid exiting the adsorbent bed was colorless (resembles the color of chloroform solvent). chloroform facilitates the desorption of resin from silica gel. the mixture was distilled at 65°c and dried at 60 °c, and obtained resin was weighed. emulsion preparation the emulsions were prepared by adding 30% of water (ph=7) to the two samples of crude oil at room temperature. the emulsification was carried out by using a mixer at a speed of (1000 rpm) for 30 min to get good water in oil (w/o) emulsion. the emulsion was then heated to 50 °c by using a heating plate on magnetic stirrer. after heating, the emulsion was transferred into a 500 ml cylinder and allowed to settle under gravity for 24 hr, the amount of resolved water will be considered the most appropriate measure of emulsion stability. to study the effect of changing resin to asphaltene ratio, emulsion samples of different weight ratios of resin to asphaltene were preperad by dissolving (0.2,0.4, 0.6 and 0.8g)of resins respectively in 10 ml toluene, then mixed with crude oil. the same procedure was carried out to monitor the effect of the addition of surface active solvents on the emulsion stability. n-heptane, toluene, heptol 50 (50% n-heptane and 50% toluene) were added to the crude oil from 10% 50% of the crude oil volume. the change in ph value of aqueous phase was carried out by adjusting the ph of the water phase using hydrochloric acid (hcl) and sodium hydroxide (naoh). the ph ranges used to study the effect of ph change on the stability of the emulsion were (2, 4, 9 and 12). another set of experiments were conducted to investigate the effect of the effect of asphaltene on the stability of iraqi water in crude oil emulsions 40 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net demulsifiers chimeic2439 and rp968 on demulsification process. the doses of these demulsifiers were (20, 40, 60, 80 and 100 ppm), added to the emulsions under stirring, then heated to 50°c using a heating plate. the final water separation percentage was calculated from: … (2) results and discussion 1separation of asphaltenes and resins from crude oil table (2) reports measurements of weight percent of asphaltenes and resins in crude oil samples, and resins to asphaltenes ratio(r/a). it can be seen from the table that basrah crude oil has high weight percent of asphaltenes and low ratio of resins to asphaltenes, and this might cause high emulsion stability. whereas, nk crude oil has high ratio of resin to asphaltenes, this explains low emulsion stability. table 2, asphaltenes and resins content in the used crude oils crude oil sample wt.% asphaltenes wt.% resins r/a basrah 4.51 29.02 5.085 nk 0.38 30.6 85.85 2stability of emulsion in this research the stability of emulsion was examined by measuring the droplet size distribution(dsd) for the two types of crude oil emulsions containing 30% water content using optical microscope (model n117m with fitted 5mp digital camera, beijing novel optics co., ltd/china).. the results are summarized in table (3). it can be shown that basrah crude oil emulsion has smaller droplet size diameter than nk crude oil emulsion. table 3, drop size distribution of emulsion droplet crude oil type 30% emulsion droplet size (micron) nk 12.91-30.98 basrah 10.33-20.8 3effect of resins to asphaltenes ratio (r/a) the role of resins to ashpaltenes ratio in stabilizing emulsion was investigated by preparing emulsions of nk and basrah crude oils containing varying amounts of resins to asphaltenes ratio. figure (1) and figure (2) show the effect of adding resins extracted from iraqi crude oils on w/o emulsion stability. it is clear that as the r/a ratio increases, the emulsion will be unstable and the amount of water separated from emulsion increases. fig. 1, effect of r/a ratio of basrah crude oil on emulsion stability as it is noticed from figure (1), basrah crude oil formed stable emulsion and only very small amount of water was resolved. this could be related to the high percentage of asphaltene. sawsan a.m. mohammed and sally d. maan -available online at: www.iasj.net ijcpe vol.17 no.2 (june 2016) 41 fig. 2, effect of r/a ratio of nk crude oil on emulsion stability for nk crude oil, figure (2) shows that increasing the resin to asphaltene ratio from 85.85 to 97.28 resulted in decreasing emulsion stability, and increasing amount of resolved water from (25-83%) respectively. addition of resins always destabilizes water-in-oil emulsion. it appears that resins act as a good solvent for asphaltenes, and at sufficiently higher concentrations are able to replace asphaltene at the water/oil interface that is likely more mobile and less likely to prevent coalescence. at very high r/a ratio, resins may act as a more competitive surface-active agent than as mediator of asphaltene adsorption [11]. fig. 3, optical microscope images showing the droplet growth with increasing r/a of basrah crude oil emulsion. the droplet size after the addition of resins to both crude oils was measured by optical microscope as in figures (3) and (4). the water droplets become larger with an increasing resin/asphaltene ratio, which means a decreasing in emulsion stability. fig. 4, optical microscope images showing the droplet growth with increasing r/a of nk crude oil emulsion 4effect of solvents addition on emulsion stability it is known that asphaltene solvency is responsible for emulsion stability. the effect of changing the nature of the crude medium by blending the crude with solvents of varying amount of aromaticity was studied for the two types of crude oil. in general, the effect of addition of the three solvents to the crude oils can be summarized as follows: for basrah crude oil emulsion, it was observed that n-heptane addition did not resolve any water. while with toluene addition water resolved in fractions (20-50%) of toluene, and with heptol addition water resolved in fractions (30-50%) with lower percentage of water separated than that obtained from toluene addition as shown in figure (5). the effect of asphaltene on the stability of iraqi water in crude oil emulsions 42 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net fig. 5, effect of added solvents on basrah crude oil after 24 hr this means that basrah crude oil has a higher tendency to form stable emulsion with water even when there are changes in the solvency of the asphaltene and resins in the crude. this can be attributed to its low resin/asphaltene ratio of 5.085 and high asphaltene content of 4.51%.whereas, nk crude oil formed unstable emulsions when adding the three solvents as shown in figure (6). it was proved to be totally unstable due to addition of toluene; it gave away all the water used in the preparation of the emulsion at 50% of toluene addition to the crude oil sample. it also gave away large amount of emulisified water due to the addition of heptol with 86.6% water separation on addition of 50% heptol to the crude oil sample. for heptane addition, the water resolved is lower than that obtained for toluene and heptol addition, and the value of water separation is 75% on the addition of 50 % heptane. this can be attributed to the high ratio of resin/asphaltene of 85.85 and low asphaltene content of 0.38%. fig. 6, effect of added solvents on nk crude oil after 24 hr 5effect of aqueous phase ph it could be concluded from figure (7), that basrah crude oil formed stable emulsion in the two ranges of ph (acidic and basic). this is due to the strong interfacial film formed by asphaltene, whereas nk crude oil formed unstable emulsion in acidic range of ph with maximum separation of 33.3% at ph =2 and did not resolve any water at basic range ph =12. crude oil emulsion contains polar fractions (asphaltenes and resins) at the interfacial film surrounding water droplets; these contain acidic and basic groups, therefore adding inorganic acid and base affect these films and their emulsion stability. the interfacial films formed by asphaltenes are stronger in acid (low ph), intermediate in strength at natural ph and become very weak or mobile films in basic ph. whereas, the films formed by resin are stronger in base and weaker in acid medium [12]. sawsan a.m. mohammed and sally d. maan -available online at: www.iasj.net ijcpe vol.17 no.2 (june 2016) 43 fig. 7, effect of ph on the two types of crude oil nk crude oil emulsion has high ratio of r/a, therefore the interfacial films are formed by resins; and this explain the behavior of nk crude oil emulsion toward the change of ph. 6effect of demulsifies dose figures (8) and (9) show the effect of added demulisifers dose on the separation efficiency for the two crude oil emulsions. fig. 8, effect of chemic2439 dose on the demulsification of basrah and nk crude oil emulsions it can be seen from figures that complete separation for nk crude oil emulsion was achieved for all doses of the two types of demulsifiers. whereas, for basrah crude oil emulsion, the maximum water separation was 41.67% at (100ppm) chemic2439 and 66.67% at (100ppm) rp968. fig.9, effect of rp968 dose on the demulsification of basrah and nk crude oil emulsions emulsion stability decreases as the concentration of the demulsifier increases up to a certain value. at this concentration, the demulsifier molecule performs a complete coverage of the water/oil interface dragging the asphaltene away from the interface. as a result, the protecting film present a round the dispersed water droplets thins, then it ruptures and coalescence occurs. kinetics of emulsion stability the rate at which the emulsion water diminishes can be defined with a first order rate equation as: ln[ ] = kc t … (3) where: ca0 initial concentration of the water in the emulsion ca concentration of the water in the emulsion at any time t time(s) the effect of asphaltene on the stability of iraqi water in crude oil emulsions 44 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net a comparison of the stability of the two crude oil samples based on their breakage rate constant is carried out using the data of 50%addition of toluene in the crude oil samples as shown below in figures (10) and (11). fig. 10, kinetic study for nk crude at 50%addition of toluene fig. 11, kinetic study for basrah crude at 50%addition of toluene from figure (10) the breakage rate constant for nk crude oil is kc=0.029 s־ˡ, whereas for basrah crude oil the breakage rate constant from figure (11) is kc= 0.004 s־ˡ. it can be seen that breakage rate constant for basrah crude oil is far less than that of nk crude oil when subjected to the same condition of solvent addition. this explains why basrah crude oil forms a more stable emulsion than nk crude oil. conclusions 1asphaltene percent in basrah crude oil is 4.51%, whereas for nk crude oil is 0.38%. 2nk crude oil emulsions have higher ratio of r/a than basrah crude oil emulsions, therefore nk emulsion has lower tendency to form stable emulsions. 3for the same water content, basrah crude oil emulsion has smaller droplet size diameter than nk crude oil emulsion. 4it is clear that as the r/a ratio increases, the looser the emulsion will be and the amount of water resolved from emulsion increases. 5in general, the effect of addition of three solvents to the crude oils can be summarized as follows: for basrah crude oil emulsion, it was observed that n-heptane addition did not resolve any water. while with toluene addition, higher percentage of separated water was obtained than from heptol addition. nk crude oil formed unstable emulsions when adding the three solvents. it was proved to be totally unstable due to addition of toluene; it gave away all the water used in the preparation of the emulsion. it also gave away large amount of emulisified water due to the addition of heptol. for heptane addition, the water resolved is lower than that obtained for toluene and heptol addition. 6basrah crude oil formed stable emulsion in the two ranges of ph (acidic and basic). this is due to the strong interfacial film formed by asphaltene, whereas nk crude oil formed unstable emulsion in acidic range of ph with maximum separation of 33.3% at ph =2 and did not resolve any water at basic range ph =12. 7complete separation for nk crude oil emulsion was achieved for all doses of the two types of sawsan a.m. mohammed and sally d. maan -available online at: www.iasj.net ijcpe vol.17 no.2 (june 2016) 45 demulsifiers. whereas, for basrah crude oil emulsion, the maximum water separation was 41.67% at (100ppm) chemic2439 and 66.67% at (100ppm) rp968. 8the process of emulsions coalescence can be defined with a first order rate equation with breakage rate constant values of 0.029 s־ˡ for nk crude oil and 0.004 s־ˡ for basrah crude using toluene as solvent. references 1xia, l., lu, s., cao, g., 2004, “stability and demulsification of emulsions stabilized by asphaltenes or resins’, journal of colloid and interface science, vol.271, pp.504506. 2fingas m. and fieldhouse b. 2003, "studies of formation process of water-in-oil emulsions", marine pollution bulletin vol.47, no. 9-12, pp.369-396. 3dalmazzone c., noik c. and clausse c., 2009," application of dsc for emulsified system characterization" ,oil & gas science and technology rev. ifp , vol.64, no. 5, pp.543-555 4ashoori, s., abedini, a., abedini, r., qorbani nasheghi, k.h., 2010,” comparison of scaling equation with neural network model for prediction of asphaltene precipitation”, journal of petroleum science and engineering, vol.72, pp.186-194. 5speight, j.g., werrick, d.l., gould, k.a., overfield, r.e., rao, b.m.l., savage, d.w., 1985,”molecular weight and association of asphaltenes: a critical review”, revue de i’institut francais du petrole, vol.40, no. 1, pp.51-56. 6abedini, a., ashoori, s., torabi, f., saki, y., dinarvand, n., 2011,”mechanism of the reversibility of asphaltene precipitation in crude oil”, journal of petroleum science and engineering, vol.78, pp.316-320. 7eskin, d., ratulowski, j., akbarzadeh, k., pan, s., 2011,”modelling asphaltene deposition in turbulent pipeline flows”, the canadian journal of chemical engineering, vol.89, pp.421-441. 8aguilar, j.i.s., neto, j.s.g., almeida, s.m., mansur, c.r.e., 2013,”evaluation of the influence of polyoxidebased surfactants on the separation process of model emulsions of asphaltenes using the ftir-atr technique”, journal of applied polymer science, vol.128, pp.1390-1397. 9mullins o. c., groenzin h., buch l., gonzalez e. b., andersen s. i., galeana c. l., 2003,”molecular size of asphaltene fractions obtained from residuum hydrotreatment”, fuel, vol.82, pp.1075-1084. 10gafonova, o.v. and yarranton, h.w., 2001,”the stabilization of water-in-hydrocarbon emulsions by asphaltenes and resins”, j. colloidal interface sci. vol.241, pp.469-478. 11al-sahhaf t., elsharkawy a. & fahim m. 2008,“stability of water-in-crude oil emulsions: effect of oil aromaticity, resins to asphaltene ratio, and ph of water”, petroleum science and technology, vol.26, no.17, pp.2009-2022. 12strassner, j.e. 1968, "effect of ph on interfacial films and stability of crude oil-water emulsions", j pet technol vol.20, no.3, pp.303-312. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.23 no.3 (september 2022) 51 – 58 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: zahraa a. kadhim , email: zah.ch97@gmail.com, name: ali h. abbar, email: ali.abbar@kecbu.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. cadmium removal using bio-electrochemical reactor with packed bed rotating cylindrical cathode: a kinetics study zahraa a. kadhim and ali h. abbar biochemical engineering department, al-khwarizmi college of engineering, university of baghdad, iraq abstract the kinetics of removing cadmium from aqueous solutions was studied using a bio-electrochemical reactor with a packed bed rotating cylindrical cathode. the effect of applied voltage, initial concentration of cadmium, cathode rotation speed, and ph on the reaction rate constant (k) was studied. the results showed that the cathodic deposition occurred under the control of mass transfer for all applied voltage values used in this research. accordingly, the relationship between logarithmic concentration gradient with time can be represented by a first-order kinetic rate equation. it was found that the rate constant (k) depends on the applied voltage, the initial cadmium concentration, the ph and the rotational speed of cathode. it was increased with increasing the applied voltage and its relationship with the applied voltage obeyed an exponential formula. the rate constant (k) was decreased with increasing the initial concentration of cadmium higher than 150ppm while at low concentrations it was increased. ph and rotational speed have different effects on the rate constant. increasing the ph from 3 to 6 increases the rate constant while a slight decrease in the rate constant occurs at ph = 7. increasing the rotation from 100 to 500 rpm increases the rate constant; however, the rate constant became approximately constant buoyed 300 rpm. keywords: cadmium; packed bed rotating electrode; microbial electrolysis cell; kinetics; reaction rate constant. received on 17/07/2022, accepted on 01/08/2022, published on 30/09/2022 https://doi.org/10.31699/ijcpe.2022.3.7 1introduction the contamination of the aquatic environment with heavy metals like copper, cobalt, lead, cadmium, and zinc is a critical issues that causing health risk because of the non-biodegradability and toxicity properties of these metals. they cause many diseases and disorders due to their affinity for bioaccumulation across the food chain even at very low concentrations [1,2]. cadmium (cd) is one of these heavy metals which has long biological halflife (more than 20 years) so they considered as highly toxic to humans. adverse impacts of cadmium can be outlined as causing acute and chronic metabolic disturbances, such as emphysema, renal damage, testicular atrophy, and hypertension [2]. numerous industrial operations, such as the non-ferrous metals purification and smelting, the manufacturing of battery, the electroplating industry, and the manufacture of inorganic pigments, lead to cadmium pollution in wastewater streams [3]. hence, developing efficient approaches for cadmium removing from wastewater is a crucial duty in terms of protecting the environment and public health. conventional methods for removing cadmium can be physical, chemical, and biological methods [4-6]. many of these methods are inefficient to remove cd (if its concentration being lower than 100 mg/l) such as chemical precipitation and adsorption. others are being expensive such as reverse osmosis, or need to large amount of chemicals such as the ion exchange method to regeneration the resin [7]. while methods like membrane processes need to high operating costs and sever from fouling [3]. electrochemical methods such as electrodeposition and coagulation are more efficient than the traditional methods and can be efficiently remove cadmium with no consumption of organic carbon and no generation of sludge, but these methods still need to relatively high energy and high capital cost with relatively low efficiency at dilute concentration [8,9]. hence, providing an ecologically friendly and cost-effective approach for removing cadmium while reducing sludge generation and lowering energy requirements remains a challenge. microbial fuel cells (mfcs) and microbial electrolysis cells (mecs) are talented methods to achieve sustainable wastewater treatment with simultaneous energy generation and value-adding products [10]. mfcs have been used to recover various metals including chromium [11], copper [12], iron [13], selenium [14], and vanadium [15] while mecs have the ability to recover heavy metals such as cobalt, lead, zinc, and cadmium [16] via applying an external voltage. few studies have been conducted on the removal of cadmium from wastewater using mecs [2, 10, 17-19]. however no previous work was conducted to remove cadmium using mec with rotating cylinderical electrode. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:zah.ch97@gmail.com mailto:zah.ch97@gmail.com mailto:ali.abbar@kecbu.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2022.3.7 z. a. kadhim and a. h. abbar / iraqi journal of chemical and petroleum engineering 23,3 (2022) 51 58 52 removal of cadmium using rotating cylinderical electrode was successfully achieved using the traditional cathodic deposition but the energy consumption still relatively high [20]. for laboratory application, batch electrochemical reactors are comprehensively approved because they allow performance data as a function of reactant concentration or conversion to be obtained. uniform current distribution over the electrode surfaces are assumed to be applied in the perfectly design of the electrochemical reactors. in industry, batch mode is often the most economical way to operate when production units are small [21]. two distinct regimes could be identified in the cathodic deposition process in batch electrochemical reactors with rotating cylindrical cathode operated at galvanostatic mode that is preferred for industrial scale. the first regime is electron transport control while the second regime is mass-transport control. in the first case, decay of concentration is linearly with time while in the second case, exponential decay of the concentration with time is occurred combined with decreasing in current efficiency with time [22, 23]. therefore, studying the kinetics of cathodic deposition is an essential process by which information about the process dynamics such as reaction rate, order of reaction, and mass transfer properties can be obtained [24]. in the case of using a batch electrochemical reactor with rotating cylindrical cathode operated under galvanostatic conditions (mass-transport control) for metal removal from waste solutions, the concentration profile of heavy metal with time can be represented by the following first order rate equation[21,24-27]: 𝐶(𝑡) = 𝐶𝑜exp⁡[−𝑘𝑡] (1) where: k refers to rate constant in min -1 to our knowledge, no study has been performed to investigate the kinetics of cd removal using a bioelectrochemical reactor with a packed bed rotating cylindrical cathode, and no rate-steady correlation has been reported based on this design of the electrochemical system. in this study, the kinetics of the electrochemical removal of cd from an aqueous solution was investigated using a bio-electrochemical reactor with a packed bed rotating cylindrical cathode based on the effect of four main variables: applied voltage, initial concentration of cd(ii), ph, and rotation speed of cathode. 2materials and methods the electrochemical system adopted in the present work for cadmium removal consists of a rotating fixed bed bioelectrochemical reactor, a hot plate magnetic stirrer (ika, germany),an electric motor (type, phoenix-usa), a power source (uni-t model: utp3315tf-l). ), and two avometers (type, kwun tong, kowloon, hk) for current and voltage measurements. fig. 1 shows a schematic diagram of the electrochemical system. the bioelectrochemical cell consisted of a cylindrical cell body (15 cm in diameter and 11 cm in length) terminated at the top with a flange of dimensions (15 cm in diameter and 0.5 cm in thickness), the cell and its flanges made of perspex. porous graphite cylinder having dimensions (10 cm in length x 9.8 cm in diameter with thickness of 0.5 cm) was used as an anode. it has an apparent surface area (270.176 cm 2 ) and purchased from (hp graphite handan co., ltd.). the cathode was a rotating cylinder of spiral-wrapped woven wire mesh, consisting of continues stainless steel mesh layers wrapped around a central rod with dimensions (15 cm x 0.8 cm) to make packed bed with dimensions (2 cm outside diameter and 4.8 cm long) made of the same material and surrounded by two teflon sleeves with an outer diameter of 2.6 cm and 2 cm long. the stainless steel woven screen used to create the cathode has a mesh of 30 wires per inch and has a specific surface area of 38.06 cm -1 [28, 29]. the catholyte chamber is made of perspex. it consists of two main parts: the first is a perforated supporting cylindrical vessel of dimensions (11 cm in length and 7 cm in diameter) perforated with holes 1 cm on its side surface. the distance between any two holes was (1.5 cm) and the total number of holes was (40). this supporting container is ended from the top with a flange of dimensions (15 cm in diameter and 0.5 cm in thickness) containing four holes (0.4 cm in diameter) for fixing the cathodic chamber to the cell body by means of screws and nets. the second part is a cylindrical ion exchange membrane chamber. it was constructed of a cylindrical cation exchange membrane with dimensions (11 cm in length and 5.6 cm in diameter) fixed at the bottom with a cylindrical perspex disc having dimensions (5.5 cm in diameter and 0.5 cm in thickness). the cation exchange membrane was (ionic-64lmr.) fig. 1. schematic diagram of the electrochemical system z. a. kadhim and a. h. abbar / iraqi journal of chemical and petroleum engineering 23,3 (2022) 51 58 53 the anodic electrode was inoculated with activated sludge as a source of bacteria taken from a local biological wastewater treatment unit in karkh no. 2 / baghdad sewage department / iraq and fed with the nutrient medium as a carbon-containing source (per liter). ): ch3coona 1 g, nah2po4 • h2o 2.45 g, na2hpo4 4.58 g, kcl 0.13 g, nhc4cl 0.31 g, ph = 7 [30]. the cathode chamber was supplied with a cathodic solution composed of cadmium chloride (cdcl2) at different concentrations based on the conditions of the experiment. all chemicals used were analytical grade (ch3coona: purity (98.5%) ltd, india, nah2po4 • h2o: purity (>97%), united kingdom, na2hpo4: purity (98%), united kingdom, kcl: purity (>99%) ltd, india, nhc4cl: purity (99%), india, cdcl2: purity (99.99%) bdh, england). a weight-to-volume ratio of 40 g/160 ml catholyte was chosen as activated sludge to catholyte ratio. a new cathodic mesh screen was used in each experiment and was cleaned by rinsing with a nitric acid solution (1 m) in an ultrasonic cleaner for 10 min and then thoroughly washed with double-distilled water before use. experiments were carried out by stirring the anolyte for one hour at a rotational speed (300 rpm) using a magnetic bar without connecting the cathode and anode to the power source for activating the bacteria in the activated sludge, then the required voltage was provided to the circuit using dc power supply by connecting the positive wire to the positive electrode while the negative to the cathode in series with a resistor 10 ω. the experiments have been done at room temperature. after applying the required voltage, samples were taken every 10 minutes for the first hour, every 30 minutes for the second hour, and then every hour until the end of electrolysis at 4 hours. cadmium concentration was measured by an atomic absorption spectrometer (varian spectraa 200 spectrometer). 3results and discussion 3.1. effect of applied voltage to determine the order of the reaction kinetics of cadmium deposition on the bioelectrochemical cell with a packed bed rotating cathode, plots of concentration profile with time at different applied voltages were generated. figure 2 shows the concentration profile with time at applied voltages of 0.6 v, 0.9 v, 1.2 v, 1.5 v and 1.8 v with the inset representing plots of ln (c/co) versus time. the effect was studied with a constant concentration of cadmium at 150 mg/l, ph = 5, and a rotational speed of 300 rpm with electrolysis time of 4h(which have been determine based on a preliminary experiment using the mentioned conditions and applied voltage of 0.6 in which cadmium removal efficiency higher than95% was observed) . it is observed that the relationship between ln (c/co) and time is almost linear with the coefficient of determination (r 2 ) greater than 0.976 confirming that the cathodic precipitation of cd is subject to a first-order reaction kinetic. table 1 displays values of the rate constant (k) at several applied voltages. it has been observed that by increasing the applied voltage, the rate constant increases and the relationship between the rate constant and the applied voltage is almost fitting to an exponential form [23]. this was interpreted as, the transfer rate of cd from the solution near the cathode surface increases with the increase in the applied voltage while decreasing the side effect of hydrogen generation at the cathode. however, by increasing the applied voltage, a mass transfer limit occurs with a slight increase in rate constant at higher voltage [24]. fig. 2. plots concentration profile with time at different applied voltages. inset: inset: ln(c/co) vs. time.. co=150mg/l, ph=5, 300rpm table 1. rate constant at different applied voltage, co=150mg/l, ph=5, 300rpm e(volt) k(min -1 ) r 2 0.6 0.016930 0.985111 0.9 0.018028 0.983117 1.2 0.019286 0.977901 1.5 0.021708 0.976634 1.8 0.024226 0.976065 the relationship between the rate constant and the applied voltage can be determined by equation (2): 𝑘 = 𝑘𝑜𝑒 −𝛽(𝐸) (2) or in linear form as: ln(k)=ln(ko) –βe (3) where: k refers to the rate constant in min -1 , ko refers to the rate constant at no current supplied, and e refers to the applied voltage in volt.β represents the slope of the line. z. a. kadhim and a. h. abbar / iraqi journal of chemical and petroleum engineering 23,3 (2022) 51 58 54 equation 2 shows that the dependence of the rate constant on the applied voltage is similar to the arrhenius formula. values of ko and β can be determined from the plot of ln(k) versus applied voltage as shown in figure 3. from fig. 3,–β=0.282475and the value of ko is equal 0.01408 min -1 with r 2 =0.98784. a similar correlation was obtained by khattab et al.[24] in their studying the kinetics of copper removal on packed bed cathode,and their relation was between the rate constant and current density instead of the applied voltage that used in the present research. however, both current density and applied voltage represent the driving force for the electrochemical reduction of heavy metals like the cadmium. fig. 3. plot of ln(k) against applied voltage 3.2. effect of the initial concentration of cadmium the effect of the initial concentration of cd ions on the rate constant was also considered. fig. 4 shows the plots of concentration profile with time at different initial cd concentration of 50, 100, 150, 200 and 250 mg/l with the inset representing plots of ln (c/co) versus time. the effect was verified at a constant applied voltage of 1.5 v, ph = 5, and 300 rpm. fig. 4. plots concentration profile with time at different initial concentration inset: ln(c/co) vs. time. e=1.5v,ph=5,300rpm from fig. 4, it can be seen that the relationship between ln(c/co) and time is almost linear with a coefficient of determination (r 2 ) greater than 0.96. the rate constant values (k) at several initial cadmium concentrations are tabulated in table 2. it was observed that the rate constant decreased with increasing initial concentration above 150ppm as shown in fig. 5. the relation could be represented by a second order polynomial formula (k = 0.0167094 + 8.208542857e-005 [cd] 3.531714286e007 [cd] 2 ) with r 2 (0.9646). a similar trend was observed by khattab et al. [24] in their study the kinetics of copper removal on a packed bed cathode. at higher concentrations, the system may come under mixed control and with increasing concentration, the system only became under control of electron transfer. however, such a phenomenon was not observed as confirmed by the high value of r 2 . a mixed control process occurred in previous studies [31, 32] table 2. rate constant at different initial concentration e=1.5v,ph=5,300rpm conc.(mg/l) k(min -1 ) r 2 50 0.020157 0.978781 100 0.020723 0.966769 150 0.021708 0.976634 200 0.018820 0.985742 250 0.015142 0.979934 fig. 5. effect of concentration on the rate constant (k) 3.3. effect of ph to demonstrate the effect of ph on the rate constant, plots of concentration profile with time were generated at different ph values as shown in fig. 6 with the inset plots of ln(c/co) versus time. the effect was studied at a constant voltage of 1.5 v, cadmium concentration of 150 mg/l, and rotation speed of 300 rpm. z. a. kadhim and a. h. abbar / iraqi journal of chemical and petroleum engineering 23,3 (2022) 51 58 55 from this set of plots, it can be seen that the relationship between ln (c/co) and time is almost linear with the coefficient of determination (r 2 ) greater than 0.96 for ph value 5-7 but at lower ph r 2 became less than 0.94, hence a deviation from linearity was happened due to effect of side reaction (hydrogen generation). the rate constant values (k) at several initial ph values are also tabulated in table 3. it was observed that the rate constant increased with increasing ph to a value of 6 and then started to a slightly decrease as the ph became more alkaline as shown in fig. 7. the relation between ph and k could be represented by a second order polynomial formula (k = 0.0008373428571 + 0.007224785714 ph 0.0005799285714 ph 2 ) with r 2 (0.9578). explanation of this behavior depends on the effect of hydrogen evolution where a side reaction is occurred on the cathode and its rate increases with decreasing ph which leads to a decrease in the transfer of cadmium towards the cathode and then a decrease in the value of the rate constant. at a ph higher than 6, cadmium ions could be precipitated as hydroxides instead of a metal and then the cadmium deposition on cathode rate decreases [33]. therefore, ph = 6 is taken into account when further study of the effect of rotational speed. fig. 6. plots concentration profile with time at different at initial ph. inset: inset: ln(c/co) vs. time.. e=1.5v,co=150mg/l,300rpm table 3. rate constant at different initial ph, e=1.5v, co=150mg/l, 300rpm ph k(min -1 ) r 2 7 0.022872 0.993228 6 0.023805 0.961809 5 0.021708 0.976634 4 0.020968 0.933699 3 0.017163 0.943200 fig. 7. effect of ph on the rate constant (k) 3.4. effect of rotation speed the effect of cathode rotation speed on the rate constant was shown in fig. 8 as plots of concentration profile with time at different rotation speeds with the inset representing the plots of ln(c/co) against time. the effect was verified at a constant voltage of 1.5 v, an initial cadmium concentration of 150 mg/l, and ph = 6. from this set of plots, it can be seen that the relationship between ln(c/co) and time is approximately linear with a coefficient of determination (r 2 ) greater than 0.96 except at rotation speed of 500rpm. rate constant values (k) at multiple rotational speeds are tabulated in table 4 and fig. 9. the relation could be represented by a second order polynomial formula (k = 0.00931242 + 6.615287143e005 (rotation speed) 7.190928571e-008 (rotation speed) 2 with r 2 (0.9608). it can be seen that increasing the rotational speed leads to increase the rate constant up to 300 rpm and beyond this value of the rotational speed, the rate constant starts to decline. this behavior can be explained as increasing the rotation speed leads to a decrease in the boundary layer thickness on the cathode surface and thus more cadmium ions can be deposited [20]. fig. 8. plots concentration profile with time at different rotation speed inset: inset: ln(c/co) vs. time e=1.5v,co=150mg/l, ph=6 z. a. kadhim and a. h. abbar / iraqi journal of chemical and petroleum engineering 23,3 (2022) 51 58 56 table 4. rate constant at different rotation speed. e=1.5v, co=150mg/l, ph=6 rotation speed rpm k(min -1 ) r 2 100 0.015348 0.990402 200 0.019015 0.985186 300 0.023805 0.961809 400 0.0234283 0.98932 500 0.0246450 0.906346 fig. 9. effect of rotation speed on the rate constant (k) it is important to note that the final concentration of cadmium under different effect of parameters were in the range of 3.5 ppm to 0.5 ppm which is higher than the standard limit for drinking water according to iraqi standards (0.003mg/l) [34]. however, the treated wastewater could be used for agricultural applications. 4conclusions it was found that the cathodic deposition of cadmium using a bioelectrochemical reactor with a packed bed rotating cylindrical cathode follows first-order kinetic properties. the results showed that the rate constant is affected by the applied voltage, the initial concentration of cadmium, ph and the rotational speed. an exponential correlation was observed between the rate constant and the applied voltage similar to the arrhenius formula. increasing the applied voltage enhances the rate constant while the concentration has the opposite effect. ph and rotational speed have different effects on the rate constant. increasing ph from 3 to 6 results in increase the rate constant while after ph 6, a decrease in the rate constant was found. the rate constant increases with increasing rotational speed up to 300 rpm and then the rate constant decreases slightly beyond this value. from a scale up point of view, the results of the present work are important in choosing the appropriate values of the applied voltage and rotational speed to obtain the same hydrodynamic similarity at the industrial applications based on their optimum values of 1.1 volts and 300 rpm. acknowledgment the authors thank the technical staff of the biochemical engineering department, al-khwarizmi college of engineering/ university of baghdad for general support. references [1] amarasinghe, b.m.w.p.k., and williams, r.a., 2007, tea waste as a low cost adsorbent for the removal of cu and pb from wastewater, chem. eng. j., vol.32, pp.299–309. [2] choi, c., hu, n., and lim, b., 2014, cadmium recovery by coupling double microbial fuel cells, bioresour. technol., vol.170, pp.361–369. [3] kurniawan, t.a., chan, g.y.s., lo, w.-h., and babel, s., 2006, physico–chemical treatment techniques for wastewater laden with heavy metals, chem. eng. j., vol.118, pp.83–98. [4] soares, e. v., and soares, h. m. v. m., 2011, bioremediation of industrial effluents containing heavy metals using brewing cells of saccharomyces cerevisiae as a green technology: a review, environmental science and pollution research, vol.19, no.4, pp.1066–1083. [5] malaviya, p., and singh, a., 2011, physicochemical technologies for remediation of chromiumcontaining waters and wastewaters, critical reviews in environmental science and technology, vol.41, no.12, pp.1111–1172. [6] mohammed, a., alsalhy, q. and ahmed, s., 2016, separation of lead (pb 2+ ) and cadmium (cd 2+ ) from single and binary salt aqueous solutions using nanofiltration membranes, journal of engineering, vol.22,no.4, pp. 50-67. [7] ahluwalia, s.s., and goyal, d., 2007, microbial and plant derived biomass for removal of heavy metals from wastewater, bioresour. technol., vol.98, pp.2243-2257. [8] khairy m., el-safty s.a., and shenashen m.a., 2014, environmental remediation and monitoring of cadmium, trend anal chem, vol.62, pp.56-68. [9] salem, m. and majeed, n. ,2019, removal of cadmium from industrial wastewater using electrocoagulation process, journal of engineering, vol.26,no.1, pp. 24-34. [10] zhang, y., yu, l., wu, d., huang, l., zhou, p., quan, x., and chen, g. , 2015, dependency of simultaneous cr(vi), cu(ii) and cd(ii) reduction on the cathodes of microbial electrolysis cells selfdriven by microbial fuel cells, j. power sources, vol.273, pp.1103–1113. [11] li, z., zhang, x., and lei, l., 2008, electricity production during the treatment of real electroplating wastewater containing cr 6+ using microbial fuel cell, process biochemistry, vol.43,no.12, pp.1352–1358. https://www.sciencedirect.com/science/article/pii/s1385894707000332 https://www.sciencedirect.com/science/article/pii/s1385894707000332 https://www.sciencedirect.com/science/article/pii/s1385894707000332 https://www.sciencedirect.com/science/article/pii/s1385894707000332 https://www.sciencedirect.com/science/article/pii/s0960852414010761 https://www.sciencedirect.com/science/article/pii/s0960852414010761 https://www.sciencedirect.com/science/article/pii/s0960852414010761 https://www.sciencedirect.com/science/article/pii/s1385894706000362 https://www.sciencedirect.com/science/article/pii/s1385894706000362 https://www.sciencedirect.com/science/article/pii/s1385894706000362 https://www.sciencedirect.com/science/article/pii/s1385894706000362 https://link.springer.com/article/10.1007/s11356-011-0671-5 https://link.springer.com/article/10.1007/s11356-011-0671-5 https://link.springer.com/article/10.1007/s11356-011-0671-5 https://link.springer.com/article/10.1007/s11356-011-0671-5 https://link.springer.com/article/10.1007/s11356-011-0671-5 https://link.springer.com/article/10.1007/s11356-011-0671-5 https://link.springer.com/article/10.1007/s11356-011-0671-5 https://link.springer.com/article/10.1007/s11356-011-0671-5 https://link.springer.com/article/10.1007/s11356-011-0671-5 https://link.springer.com/article/10.1007/s11356-011-0671-5 https://link.springer.com/article/10.1007/s11356-011-0671-5 https://www.joe.uobaghdad.edu.iq/index.php/main/article/view/232 https://www.joe.uobaghdad.edu.iq/index.php/main/article/view/232 https://www.joe.uobaghdad.edu.iq/index.php/main/article/view/232 https://www.joe.uobaghdad.edu.iq/index.php/main/article/view/232 https://www.joe.uobaghdad.edu.iq/index.php/main/article/view/232 https://www.sciencedirect.com/science/article/pii/s0960852405005675 https://www.sciencedirect.com/science/article/pii/s0960852405005675 https://www.sciencedirect.com/science/article/pii/s0960852405005675 https://www.sciencedirect.com/science/article/pii/s0960852405005675 https://www.sciencedirect.com/science/article/pii/s0165993614001587 https://www.sciencedirect.com/science/article/pii/s0165993614001587 https://www.sciencedirect.com/science/article/pii/s0165993614001587 https://joe.uobaghdad.edu.iq/index.php/main/article/view/j.eng.2020.01.03 https://joe.uobaghdad.edu.iq/index.php/main/article/view/j.eng.2020.01.03 https://joe.uobaghdad.edu.iq/index.php/main/article/view/j.eng.2020.01.03 https://joe.uobaghdad.edu.iq/index.php/main/article/view/j.eng.2020.01.03 https://www.sciencedirect.com/science/article/pii/s0378775314015377 https://www.sciencedirect.com/science/article/pii/s0378775314015377 https://www.sciencedirect.com/science/article/pii/s0378775314015377 https://www.sciencedirect.com/science/article/pii/s0378775314015377 https://www.sciencedirect.com/science/article/pii/s0378775314015377 https://www.sciencedirect.com/science/article/pii/s0378775314015377 https://www.sciencedirect.com/science/article/pii/s135951130800250x https://www.sciencedirect.com/science/article/pii/s135951130800250x https://www.sciencedirect.com/science/article/pii/s135951130800250x https://www.sciencedirect.com/science/article/pii/s135951130800250x https://www.sciencedirect.com/science/article/pii/s135951130800250x z. a. kadhim and a. h. abbar / iraqi journal of chemical and petroleum engineering 23,3 (2022) 51 58 57 [12] heijne, a. t., liu, f., weijden, r. van der, weijma, j., buisman, c. j. n., and hamelers, h. v. m., 2010, copper recovery combined with electricity production in a microbial fuel cell, environmental science & technology, vol.44, no.11, pp.4376– 4381. [13] lefebvre, o., tan, z., shen, y., and ng, h. y., 2013, optimization of a microbial fuel cell for wastewater treatment using recycled scrap metals as a cost-effective cathode material, bioresource technology, vol.127, pp.158–164. [14] catal, t., bermek, h., and liu, h., 2009, removal of selenite from wastewater using microbial fuel cells, biotechnology letters, vol.31, no.8, pp.1211– 1216. [15] zhang, b., zhao, h., shi, c., zhou, s., and ni, j., 2009, simultaneous removal of sulfide and organics with vanadium (v) reduction in microbial fuel cells, journal of chemical technology & biotechnology, vol.84, no.12, pp.1780–1786. [16] jiang, l., huang, l., and sun, y., 2014, recovery of flakey cobalt from aqueous co(ii) with simultaneous hydrogen production in microbial electrolysis cells, int. j. hydrogen energy, vol.39, pp.654–663. [17] abourached, c., catal, t., and liu, h., 2014, efficacy of single-chamber microbial fuel cells for removal of cadmium and zinc with simultaneous electricity production, water research, vol.51, pp.228–233. [18] modin, o., wang, x., wu, x., rauch, s., and fedje, k. k., 2012, bioelectrochemical recovery of cu, pb, cd, and zn from dilute solutions, journal of hazardous materials, vol.235-236, pp.291–297. [19] chen, y., shen, j., huang, l., pan, y., and quan, x., 2016, enhanced cd(ii) removal with simultaneous hydrogen production in biocathode microbial electrolysis cells in the presence of acetate or nahco3, international journal of hydrogen energy, vol.41, no.31, pp. 13368–13379. [20] abbar, a.h., salman, r.h. abbas, a.s. cadmium removal using a spiral-wound woven wire meshes packed bed rotating cylinder electrode. environmental technology & innovation. 2019, 13, 233. [21] scott, k. (2007). reactor modelling for electrochemical processes. journal of chemical technology & biotechnology, 54(3), 257–266. doi:10.1002/jctb.280540308. [22] paul chen, j., & lim, l. l. (2005). recovery of precious metals by an electrochemical deposition method. chemosphere, 60(10), 1384–1392. [23] kaminari, n. m. s.; ponte, m. j. j. s.; ponte, h. a. (2018). mass transfer correlation for the removal of copper ions from wastewater. revista de engenharia térmica, 9(1-2), 63–. doi:10.5380/reterm.v9i1-2.61932. [24] khattab, i. a., shaffei, m. f., shaaban, n. a., hussein, h. s., & abd el-rehim, s. s. study the kinetics of electrochemical removal of copper from dilute solutions using packed bed electrode. egyptian journal of petroleum, 2014, 23(1), 93. [25] granados, paola; rivera, fernando f.; gonzalez, ignacio; rivero, eligio p. "modeling and simulation of a rotating cylinder electrode reactor for metal recovering." ecs transactions 20, no. 1 (2009): 73. doi:10.1149/1.3268374. [26] gabe, d. r. (1995). rotating electrodes for use in electrodeposition process control. plating & surface finishing, 82, 69-76. [27] trinidad, p., walsh, f.c., & gilroy, d. (1998). conversion expressions for electrochemical reactors which operate under mass transport controlled reaction conditions. part i: batch reactor, pfr and cstr. international journal of engineering education, 14, 431-441. [28] saad, duaa r.; alismaeel, ziad t.; abbar, ali h. (2020). cobalt removal from simulated wastewaters using a novel flow-by fixed bed bioelectrochemical reactor. chemical engineering and processing process intensification.108097 doi: 10.1016 /j.cep.2020 .108097. [29] saad, d. r., alismaeel, z. t. and abbar, a. h. (2020) “removal of cadmium from simulated wastewaters using a fixed bed bio-electrochemical reactor”, journal of engineering, 26(12), pp. 110– 130. doi: 10.31026/j.eng.2020.12.07. [30] luo, haiping; liu, guangli; zhang, renduo; bai, yaoping; fu, shiyu; hou, yanping (2014). heavy metal recovery combined with h2 production from artificial acid mine drainage using the microbial electrolysis cell. journal of hazardous materials, 270(), 153–159. doi:10.1016/j.jhazmat.2014.01.050. [31] chu, a. k. p., fleischmann, m., & hills, g. j. packed bed electrodes. i. the electrochemical extraction of copper ions from dilute aqueous solutions .journal of applied electrochemistry, 1974 4(4), 323. [32] ruotolo, l.a.m. and gubulin, j.c. electrodeposition of copper ions on fixed bed electrodes: kinetics and hydrodynamic study. braz. j. chem. eng. 2002, 19 (1), 105. [33] purkayastha, u. mishra, s. biswas, a comprehensive review on cd(ii)removal from aqueous solution, j. water process eng. 2 (2014) 105–128. [34] abdul jabar m. a. b. and thabit j. a. chemical pollution risks for many drinking water sources in baghdad city, iraq, pol. j. environ. stud. vol. 30, no. 2 (2021), 1203-1214. https://pubs.acs.org/doi/abs/10.1021/es100526g https://pubs.acs.org/doi/abs/10.1021/es100526g https://pubs.acs.org/doi/abs/10.1021/es100526g https://pubs.acs.org/doi/abs/10.1021/es100526g https://pubs.acs.org/doi/abs/10.1021/es100526g https://pubs.acs.org/doi/abs/10.1021/es100526g https://www.sciencedirect.com/science/article/pii/s0960852412015076 https://www.sciencedirect.com/science/article/pii/s0960852412015076 https://www.sciencedirect.com/science/article/pii/s0960852412015076 https://www.sciencedirect.com/science/article/pii/s0960852412015076 https://www.sciencedirect.com/science/article/pii/s0960852412015076 https://link.springer.com/article/10.1007/s10529-009-9990-8 https://link.springer.com/article/10.1007/s10529-009-9990-8 https://link.springer.com/article/10.1007/s10529-009-9990-8 https://link.springer.com/article/10.1007/s10529-009-9990-8 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.2244 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.2244 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.2244 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.2244 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.2244 https://www.sciencedirect.com/science/article/pii/s0360319913026256 https://www.sciencedirect.com/science/article/pii/s0360319913026256 https://www.sciencedirect.com/science/article/pii/s0360319913026256 https://www.sciencedirect.com/science/article/pii/s0360319913026256 https://www.sciencedirect.com/science/article/pii/s0043135413008889 https://www.sciencedirect.com/science/article/pii/s0043135413008889 https://www.sciencedirect.com/science/article/pii/s0043135413008889 https://www.sciencedirect.com/science/article/pii/s0043135413008889 https://www.sciencedirect.com/science/article/pii/s0043135413008889 https://www.sciencedirect.com/science/article/pii/s0304389412008023 https://www.sciencedirect.com/science/article/pii/s0304389412008023 https://www.sciencedirect.com/science/article/pii/s0304389412008023 https://www.sciencedirect.com/science/article/pii/s0304389412008023 https://www.sciencedirect.com/science/article/pii/s0360319916305997 https://www.sciencedirect.com/science/article/pii/s0360319916305997 https://www.sciencedirect.com/science/article/pii/s0360319916305997 https://www.sciencedirect.com/science/article/pii/s0360319916305997 https://www.sciencedirect.com/science/article/pii/s0360319916305997 https://www.sciencedirect.com/science/article/pii/s0360319916305997 https://www.sciencedirect.com/science/article/pii/s2352186418303912 https://www.sciencedirect.com/science/article/pii/s2352186418303912 https://www.sciencedirect.com/science/article/pii/s2352186418303912 https://www.sciencedirect.com/science/article/pii/s2352186418303912 https://www.sciencedirect.com/science/article/pii/s2352186418303912 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.280540308 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.280540308 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.280540308 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.280540308 https://www.sciencedirect.com/science/article/pii/s0045653505002420 https://www.sciencedirect.com/science/article/pii/s0045653505002420 https://www.sciencedirect.com/science/article/pii/s0045653505002420 https://revistas.ufpr.br/reterm/article/view/61932 https://revistas.ufpr.br/reterm/article/view/61932 https://revistas.ufpr.br/reterm/article/view/61932 https://revistas.ufpr.br/reterm/article/view/61932 https://revistas.ufpr.br/reterm/article/view/61932 https://www.sciencedirect.com/science/article/pii/s1110062114000154 https://www.sciencedirect.com/science/article/pii/s1110062114000154 https://www.sciencedirect.com/science/article/pii/s1110062114000154 https://www.sciencedirect.com/science/article/pii/s1110062114000154 https://www.sciencedirect.com/science/article/pii/s1110062114000154 https://iopscience.iop.org/article/10.1149/1.3268374/meta https://iopscience.iop.org/article/10.1149/1.3268374/meta https://iopscience.iop.org/article/10.1149/1.3268374/meta https://iopscience.iop.org/article/10.1149/1.3268374/meta https://iopscience.iop.org/article/10.1149/1.3268374/meta https://www.nmfrc.org/pdf/2018/36david_gabe1995.pdf https://www.nmfrc.org/pdf/2018/36david_gabe1995.pdf https://www.nmfrc.org/pdf/2018/36david_gabe1995.pdf https://www.sciencedirect.com/science/article/pii/s0255270120305596 https://www.sciencedirect.com/science/article/pii/s0255270120305596 https://www.sciencedirect.com/science/article/pii/s0255270120305596 https://www.sciencedirect.com/science/article/pii/s0255270120305596 https://www.sciencedirect.com/science/article/pii/s0255270120305596 https://www.sciencedirect.com/science/article/pii/s0255270120305596 https://joe.uobaghdad.edu.iq/index.php/main/article/view/j.eng.2020.12.07 https://joe.uobaghdad.edu.iq/index.php/main/article/view/j.eng.2020.12.07 https://joe.uobaghdad.edu.iq/index.php/main/article/view/j.eng.2020.12.07 https://joe.uobaghdad.edu.iq/index.php/main/article/view/j.eng.2020.12.07 https://joe.uobaghdad.edu.iq/index.php/main/article/view/j.eng.2020.12.07 https://www.sciencedirect.com/science/article/pii/s0304389414000740 https://www.sciencedirect.com/science/article/pii/s0304389414000740 https://www.sciencedirect.com/science/article/pii/s0304389414000740 https://www.sciencedirect.com/science/article/pii/s0304389414000740 https://www.sciencedirect.com/science/article/pii/s0304389414000740 https://www.sciencedirect.com/science/article/pii/s0304389414000740 https://link.springer.com/article/10.1007/bf00608974 https://link.springer.com/article/10.1007/bf00608974 https://link.springer.com/article/10.1007/bf00608974 https://link.springer.com/article/10.1007/bf00608974 https://link.springer.com/article/10.1007/bf00608974 https://www.scielo.br/j/bjce/a/hgdhdzhkwzp6wpbxxfr7wmq/abstract/?lang=en https://www.scielo.br/j/bjce/a/hgdhdzhkwzp6wpbxxfr7wmq/abstract/?lang=en https://www.scielo.br/j/bjce/a/hgdhdzhkwzp6wpbxxfr7wmq/abstract/?lang=en https://www.scielo.br/j/bjce/a/hgdhdzhkwzp6wpbxxfr7wmq/abstract/?lang=en https://www.sciencedirect.com/science/article/pii/s2214714414000415 https://www.sciencedirect.com/science/article/pii/s2214714414000415 https://www.sciencedirect.com/science/article/pii/s2214714414000415 https://www.sciencedirect.com/science/article/pii/s2214714414000415 http://www.pjoes.com/pdf-120767-60970?filename=60970.pdf http://www.pjoes.com/pdf-120767-60970?filename=60970.pdf http://www.pjoes.com/pdf-120767-60970?filename=60970.pdf http://www.pjoes.com/pdf-120767-60970?filename=60970.pdf z. a. kadhim and a. h. abbar / iraqi journal of chemical and petroleum engineering 23,3 (2022) 51 58 58 احيائي ذات القطب الكاثودي الدوار ذو -ازالة الكادميوم باستخدام مفاعل كهروكيميائي دراسة حركية التفاعل: الحشوه الثابته علي حسين عبارو زهراء علي كاظم الخوارزمي/ جامعة بغدادقسم الهندسه الكيميائيه االحيائيه/ كلية الهندسه ةالخالص احيائي ذات -تم دراست حركية التفاعل الزالة الكادميوم من المحاليل المائيه باستخدام مفاعل كهروكيميائي قطب كاثودي دوار مؤلف من حشوه ثابته. حيث تم دراسة تاثير كل من الجهد الكهربائي المسلط ,التركيز ( . اظهرت النتائج ان kالكاثود والداله الحامضيه على ثابت معدل التفاعل ) البدائي للكادميوم ,سرعة دوران الترسيب الكاثودي للكادميوم يحدث تحت تاثير انتقال الكتله لكل قيم الجهود الكهربائيه المسلطه وبناء على المرتبه االولى .ذلك يمكن تمثيل العالقة بين تغيير التركيز اللوغاريتمي مع الزمن بمعادلة تفاعل من وجد ان ثابت معدل التفاعل يعتمد على الجهد الكهربائي المسلط , التركيز البدائي للكادميوم ,الداله الحامضيه وسرعة الدوران . حيث انه تمت زيادته مع زيادة الجهد المسلط وامتثلت عالقته بالجهد المسلط معادلة أسية. بينما تم زيادته عند ppm 150زيادة التركيز األولي للكادميوم أعلى من( مع kينخفض المعدل الثابت ) التراكيز المنخفضة. األس الهيدروجيني وسرعة الدوران لهما تأثيرات مختلفة على ثابت المعدل. تؤدي زيادة الرقم إلى زيادة ثابت المعدل بينما يحدث انخفاض طفيف في ثابت المعدل عند 6إلى 3األس الهيدروجيني من ( يؤدي الى زيادة ثابت معدل rpm5 00( الى )rpm 100.. زيادة سرعة التدوير من )7الهيدروجيني = ( .rpm 300)عندالتفاعل ومع ذلك ، أصبح ثابت المعدل ثابًتا تقريًبا التفاعلالخواص الحركية, ثابت معدل , خلية التحليل الكهربائي الميكروبية ,الكادميومالكلمات الدالة: iraqi journal of chemical and petroleum engineering vol.13 no.1 (march 2012) 11-18 issn: 1997-4884 production and evaluation of biodiesel from sheep fats waste ammar salih abbas* and toleen salah othman *university of baghdad, college of engineering, chemical engineering department abstract animal fats are a good, promising and ethical alternative source for biodiesel production, but they need more complex treatments than vegetable oils. iraqi butchery plants waste fats (sheep fat) which are suggested as feedstock to produce biodiesel. this type of fat contains a large quantity of free fatty acids (ffas) (acid number 49.13 mg koh/g of fat). the direct transesterification of such fats produce high amount of soap instead of desired biodiesel, so a pre-treatment step (to reduce ffas) is necessary before transesterification. this step was done by esterification of the free fatty acids in the fat by adding ethanol and using 1% acid catalyst (h2so4) for 30 minutes. the results showed that the acid number of sheep fat after pre-treatment step reduced to 0.97 mg koh/g of fat at esterification step. transesterification of treated fats (produce from esterification) used to convert biodiesel. the maximum yield of biodiesel was about 85 vol. % for treated fats obtained with 25/100 ethanol/fat wt. ratio, 70 ° c reaction temperature and 50 minutes total treatment period (pre-treatment step and transesterification reaction). the suggested model of the production rate kinetic of transesterification reaction, found that the production rate is inversely proportional with the volume of biodiesel produced with activation energy of 25320 j/mole. keywords: biodiesel, sheep fats waste, esterification, alkyl catalyst transesterification introduction the world energy crisis is a result of population growth and increasing consumption of energy in both developed countries and emerging economies. from 1973 to 2007, worldwide primary emerging consumption almost doubled from 256 to 505 million gaga joules (gj) [1] . this crisis will expand especially with the predicted decline of petroleum reserves that will occur at a rate between 2 and 3% per year starting in 2010 [2] . therefore, there is a strong need to replace petroleum with other, more sustainable energy sources such as solar energy, biomass, geothermal, wind and water. biomass is a renewable material such as wood, agriculture crops or animal's wastes, and municipal wastes, especially when used as a source of fuel or energy. biomass burned directly or processed into biofuels such as methane (biogas), ethanol (bioethanol) and biodiesel. historically the first car group in the usa operated on ethanol fuel university of baghdad college of engineering iraqi journal of chemical and petroleum engineering production and evaluation of biodiesel from sheep fats waste www.iasj.netavailable online at: -ijcpe vol.13 no.1 (march 2012) 21 (bioethanol). then the inventor dr. rudolf diesel at 1900 used the first diesel engine and operated it by peanut oil [3] . recently engines don’t accept these oils (and animal fats) as a fuel due to their inappropriate physical properties such as longer molecule chains, lower pour points, higher flash points, and chemical composition of unprocessed oils and fats. these features cause poor atomization, bad vapor–air mixing, low pressure, and incomplete combustion and engine deposits. it is possible to reduce the viscosity of oils and fats to improve the physical features through dilution, pyrolysis, micro emulsion and transesterification [4] . transesterification and esterification produced biodiesel. biodiesel is one of the most used fuels in diesel engines without any major modification produced from vegetable oils and waste animal fats. biodiesel has attracted governmental attention and support as an alternative, renewable, and potentially “clean” fuel for diesel engines. since biodiesel derived largely from renewable biological resources, biodiesel is safer for the environment and produces significantly less air pollution compared to petroleum diesel [5,6] . one popular process for producing biodiesel from the fats/oils is transesterification of triglyceride by methanol or ethanol to make methyl esters or ethyl ester of the straight chain fatty acid. the purpose of this process is to lower the viscosity of the oil [7] . oil esters (biodiesel) have certain advantages such as lower viscosity, lower flash point, higher vapor pressure and easier processing relative to animal fatty acid esters, but they are noneconomic, non-feasible due to many vegetable oils (about 95%) used in the production of biodiesel are edible oils, and hence are valuable. for the same reason, the use of edible vegetable oils for biodiesel production leads to short ages of the food. animal fats in human food constitute health hazards; this is one of the reasons for their low-cost [8] . the present work intends to produce ethyl ester from the waste sheep fat by alkyl catalyst transesterification. animal fats are a good alternative source for biodiesel production but their treatment is more complex than fresh vegetable oils [9] . animal fats contain a large amount of free fatty acids, so that pretreatment to reduce the ffa is a necessary step. then the alkali catalyst will react with the free fatty acids to form soaps [10] . this reaction is undesirable and reduces the yield of the biodiesel product. the pretreatments step is done by two ways: the first way is the extraction of the free fatty acids (ffas) in the fat by adding ethanol; and, the second way is the esterification of free fatty acids (ffas) in the fat by adding ethanol and used acid catalyst (h2so4). the effects of ethanol /fat wt. ratio, and the reaction temperature are studied for the conversion of sheep fat to optimize the reaction conditions. this study is conducted to utilize a process for producing and purifying ethyl esters (biodiesel) from the waste of animal fats to use locally in electrical-generators of animals butchery plant. operating conditions such as temperature, ethanol/fat wt. ratio and reaction time were studied. the produced biodiesel evaluated by measuring its properties. experimental work materials 1. sheep fats used in the present study were collected from main slaughterhouses in iraq. at the laboratory, they were melted by ammar salih abbas and toleen salah othman 21 )2201 march( 1no. 3ijcpe vol.1 www.iasj.netonline at: available slow heating to 60 °c and filtered in order to obtain the fat and remove gums, protein residues, and suspended particles. thus, the obtained fats which were homogenous in nature were stored in tight opaque plastic jars to prevent oxidation. the specific gravity of the sheep fat was 0.8772. 2. ethyl alcohol was obtained from local markets with a purity of 88 to 90% and a specific gravity 0.7692. 3. sodium hydroxide as a base catalyst (riedel_dehaen ag seelze_hannover chem. rian, plozchen, dab7, b.p.1968 m.wt. 40). 4. sulfuric acid was obtained from local market. the purity of this acid was 98% (sp.gr. was 1.84) ar. 5. glycerol (etwa 87%) zur analysis c3h8o3. 6. phenolphthalein (as an indicator). equipment the equipment used in this study for the pretreatment step (esterification) and transesterification steps is shown schematically in figure 1. fig. 1, schematic diagram of the equipment the main parts of the equipment are: 1. heat flat magnetic stirrer. 2. reflux condenser. 3. centrifuge. 4. mercury thermometer from zero to 250 °c. 5. 3 necks flask (500 ml(. 6. sensitive balance. 7. chiller. esterification of sheep fat the esterification reaction was carried out between acid and free fatty acid (ffa) to produce ester (biodiesel) and water. the ffa reduced in the fat to less than 2 mg koh/g of fat, which to be suitable to produce biodiesel in transesterification reaction [1] . the system was maintained at atmospheric pressure and the experiments were carried out at constant temperature. the agitation was kept constant at 300-rpm. this method was studied at different percentages of ethanol/fat wt. ratio from 20/100 to 40/100, and used 1% of sulfuric acid as a catalyst at a constant time of about 30 minutes, and at different temperatures (40 to 70 °c). the reactor was loaded with about 50g of sheep fat, preheated to the desired temperature and the agitation started. the reaction started when ethyl alcohol was added to the sheep fat in the reactor. after 10 minutes from the reaction, one percent of sulfuric acid was added and the reaction continued to 30 minutes. then, the mixture was transferred to the separating funnel to separate treated fat from alcohol. the top layer was alcohol acid, and part from ffa in the fat and the bottom layer was a treated fat. the separating time was about 30 minutes and it was instant to start the transesterification method. production of biodiesel by alkyl catalyst transesterification the ethyl alcohol and base catalyst (sodium hydroxide) are used to produce biodiesel, but in this way the fat is not used directly. fat contains a production and evaluation of biodiesel from sheep fats waste www.iasj.netavailable online at: -ijcpe vol.13 no.1 (march 2012) 21 high number of ffa; this leads to a chemical reaction between ffa in the fat and the base catalyst to form soaps. after the pre-treatment method of the ffa in the fat, this reaction is desirable to yield biodiesel. the system was maintained at atmospheric pressure and experiments were carried out at constant temperature. the agitation was kept constant at 300-rpm. this method was studied at different percentages of ethanol/fat wt. ratio from 20/100 to 40/100; the temperatures of the reaction ranged from 40 to 70 °c and 1% of sodium hydroxide at different times (10, 15, 20, 25, 30, 45, 60 minutes). the reactor was loaded with the treated fat, which was produced from the separating funnel by the pretreatment method (esterification), preheated to the desired temperature and the agitation started. the sodium hydroxide dissolved in ethanol and the reaction started when the alcoholic solution was added to the fat. washing excess alcohol and residual catalyst were washed from the biodiesel with water. water sprayed in to the top of the separating funnel at low velocity. the excess alcohol and catalyst were removed by the water as it percolated through the separating funnel. results and disscutions pre-treatment of ffas in the fat from the experimental works of the esterification step, the acid value was reduced from 49.13 mg koh/g of fat to 0.97 mg koh/g of fat and the optimum conversion of ffas was 98% at 25/100 of ethanol/ fat wt. ratio after 30 minutes. the best temperature was 70 °c for this type of pre-treatment. the pretreatment reactions act as the limiting step of the production. after reducing the ffas in the fat, the transesterification reaction converts esters from long chain fatty acids into mono alkyl esters. effect of operating temperature and time on the biodiesel yield operating temperature and reaction time that affect the biodiesel yield from animal fat (sheep fat) was studied in the temperature range from 40 to 70 °c and in the reaction time of up to 60 minutes. figures 2 to 5 show the biodiesel yield with reaction time and temperature by esterification method (animal fat treated with h2so4) of the transesterfication. the yield of biodiesel after transesterfication reaction was 61.7 vol. % at 70 °c after 30 minutes, and reached 55.2 vol. % at 40 °c after 30 minutes with 20/100 ethanol/fat wt. ratio (as shown in fig.2). at 25/100 ethanol/fat wt. ratio (as shown in fig. 3) the yield of biodiesel was 85.3 vol. % at 70 °c after 20 minutes, and reached 73.4 vol. % at the temperature of 40 °c after 30 minutes. the yield of biodiesel at 30/100 ethanol/fat wt. ratio (as shown in fig.4) was 72.1 vol. % at 70 °c after 30 minutes, and reached 57.5 vol. % at 40 °c after 30 minutes. while at 40/100 ethanol/fat wt. ratio (as shown in fig.5), the yield of biodiesel was 76.5 vol. % at reaction temperature of 70 °c after 30 minutes and reached 58.4 vol. % at 40° c after 60 minutes. from these results, the best yield of biodiesel by this method was 85.3 vol. % at 25/100 ethanol/ fat ratio at 70° c after 20 minutes. increasing the temperature causes an increase in molecule activity. this means that more molecules have more energy; thus, the possibility of molecule to react is increased, and this causes the removing of water formed during the reaction. then consequently, higher conversion values ammar salih abbas and toleen salah othman 21 )2201 march( 1no. 3ijcpe vol.1 www.iasj.netonline at: available that cause more yield of product material are obtained. time, min 0 10 20 30 40 50 60 70 b io d ie s e l y ie ld , v o l. % 0 10 20 30 40 50 60 70 t=40° c t=50° c t=60° c t=70° c etoh/fat = 20/100 fig.2, effect of the reaction temperature on biodiesel yield, 20/100 ethanol/fat wt. ratio time, min 0 10 20 30 40 50 60 70 b io d ie s e l y ie ld , v o l. % 0 20 40 60 80 100 t=40° c t=50° c t=60° c t=70° c etoh/fat = 25/100 fig.3, effect of the reaction temperature on biodiesel yield, 25% ethanol/fat wt. ratio time, min 0 10 20 30 40 50 60 70 b io d ie s e l y ie ld , v o l. % 0 20 40 60 80 t=40° c t=50° c t=60° c t=70° c etoh/fat = 30/100 fig.4, effect of the reaction temperature on biodiesel yield, 30% ethanol/fat wt. ratio time, min 0 10 20 30 40 50 60 70 b io d ie s e l y ie ld , v o l. % 0 20 40 60 80 t=40° c t=50° c t=60° c t=70° c etoh/fat = 40/100 fig.5, effect of the reaction temperature on biodiesel yield, 40% ethanol/fat wt. ratio the effect ethyl alcohol/fat wt. ratio on the biodiesel yield the experiments of transesterification by esterification step were carried out by varying the ethanol/oil wt. ratio from 20/100 to 40/100. figures 6 to 9 show the effect of the ethyl alcohol/ fat ratio and time on the biodiesel yield by esterification step of the transesterfication. as can be observed, with 20/100 ethanol/fat wt. ratio, the yield of biodiesel was near 61.7 vol. % after 30 minutes. the biodiesel yield increased as the weight ratio increased, with the best results (about 85%) being for an ethanol/fat wt. ratio 25/100 after 20 minutes. at 30/100 ethanol/fat wt. ratio the yield of biodiesel was 72.1 vol. % after 30 minutes. nevertheless, a later increase of ethanol/fat wt. ratio to 40/100 did not result in an increase in the yield, since a lower value was obtained, 76.5 vol. %. increasing in ethanol/fat wt. ratio causes decreasing the biodiesel yield, due to the higher weight ratio of ethanol/fat leads to complications in the separation of glycerol because the ethanol excess hinders the decantation by gravity so that the apparent yield of esters decreases since part of the glycerol remains in the biodiesel phase. production and evaluation of biodiesel from sheep fats waste www.iasj.netavailable online at: -ijcpe vol.13 no.1 (march 2012) 21 ethanol/fat ratio, % 15 20 25 30 35 40 45 b io d ie s e l y ie ld , v o l. % 0 20 40 60 80 100 time= 10 min. time= 15 min. time= 20 min. time= 25 min. time= 30 min. time= 45 min. time= 60 min. temp. = 40° c fig.6, effect of the ethyl alcohol/ fat wt. ratio and time on the reaction on biodiesel yield, at the temperature 40° c ethanol/fat ratio, % 15 20 25 30 35 40 45 b io d ie s e l y ie ld , v o l. % 20 40 60 80 100 time= 10 min. time= 15 min. time= 20 min. time= 25 min. time= 30 min. time= 45 min. time= 60 min. temp. = 50° c fig.7, effect of the ethyl alcohol/ fat wt. ratio and time on the reaction on biodiesel at the temperature 50° c ethanol/fat ratio, % 15 20 25 30 35 40 45 b io d ie s e l y ie ld , v o l. % 20 40 60 80 100 time= 10 min. time= 15 min. time= 20 min. time= 25 min. time= 30 min. time= 45 min. time= 60 min. temp. = 60° c fig.8, effect of the ethyl alcohol/ fat wt. ratio and time on the reaction on biodiesel yield, at the temperature 60 °c ethanol/fat ratio, % 15 20 25 30 35 40 45 b io d ie s e l y ie ld , v o l. % 20 40 60 80 100 time= 10 min. time= 15 min. time= 20 min. time= 25 min. time= 30 min. time= 45 min. time= 60 min. temp. = 70° c fig.9, effect of the ethyl alcohol/ fat wt. ratio and time on the reaction on biodiesel yield, at the temperature 70°c kinetics of production rate kinetics studies for data obtained from laboratory unit usually play an important role in modeling and scale up designs for new biodiesel production units. in order to find the rate of a product that describes the effects of temperature, and the time of the reaction on production rate, kinetic model of production was suggested and a chosen model fits the data with a higher correlation coefficient. this model is given by equation (1) below: n ydtcbta rtek ry )()( )/exp(     …(1) where: dt dy ry  production rate of biodiesel (vol. % / min). y = vol. % of biodiesel. t = reaction time (min). k° = frequency constant (( vol. %) 1-n / time). e = activation energy (j/mole). n = reaction order. a, c = arbitrary constant. b, d = arbitrary constant (k -1 ) ammar salih abbas and toleen salah othman 21 )2201 march( 1no. 3ijcpe vol.1 www.iasj.netonline at: available the yield of the product (y) was fitted by the fourth order polynomial degree formula according to the time (for certain temperature). then dy over dt has been calculated by the differentiation of the polynomial equations. this step was repeated for other temperatures. after that, the obtained data of dy/dt was regarded with the suggested models (eq. 1). the correlated coefficient of the suggested model shows excellent presentation (> 0.9) of data by the suggested model of eq. 1. constant values of the suggested model (eq.1) are summarized in table 1. table 1, constant values of the suggested model (eq.1) constant value transesterification by esterification pretreatment k° (vol. % 1-n / time) 1.18*10 8 e (j/mole). 25320 a 1 b (k -1 ) 3.85 c 0.022 d (k -1 ) 0.003 n 2.0 statistical calculation of the suggested model for experimental data shows that the solution of the model (eq.1) is proportionally correlated with the experimental data. the distribution of the experimental data around the model solution (regression coefficient (r)) is about 0.9618, standard deviation (s) is 1.056, and average relative error is -0.1256 in 95 % confidence level, as summarized in table 2. predicted values calculated from empirical model (eq. 1) and experimental data are shown in figure 10. table 2, statistical analysis of the model statistical analysis esterification method regression coefficient (r) 0.9618 standard deviation (s) 1.056 average relative error -0.1256 confidence level 95% real production rate, vol.%/min 0 2 4 6 8 10 12 p re d ic te d p ro d u c ti o n r a te , v o l. % /m in 0 2 4 6 8 10 12 acid fig.10, experimental and predicted values of apparent rate constant by using suggested model of esterification method conclusion according to the results obtained from this study, the following conclusions were obtained: 1. the ffas pre-treatment of sheep fat by esterification method is more efficient. the acid value of fat was lowered from 49.14 mg koh/g of fat to 0.97 mg koh/g of fat at a conversion of 98%. 2. the maximum yield of biodiesel produced by this process was about 85 vol. % at the conditions ethanol/fat wt. ratio 25/100, reaction temperature 70 ° c and 20 minutes. references 1. khan a. k., "biodiesel kinetics & catalyst development", thesis, university of queensland, 2002. 2. campbell c., '' the rimini an oil depletion protocol heading off production and evaluation of biodiesel from sheep fats waste www.iasj.netavailable online at: -ijcpe vol.13 no.1 (march 2012) 21 economic chaos and political conflict during the second half of the age of oil'', energy policy, vol. 34, pp. from to 1319, 2006. 3. kothari d.p., singal k.c., ranjan r., a book of ''renewable energy sources and emerging technologies'', published by wiley-vch verlag gmbh and co. kgaa, weinheim. isbn 9783-527-40804-7, pp. 61-67, 2008. 4. ma f., hanna m.a., ''biodiesel production'', journal of bio source. technology, vol.70, pp.1-15, 1999. 5. freedman b., pryde e. h., mounts t. l.," variables affecting the yields of fatty esters from transesterfication vegetable oils". journal of american oil chemicals society. vol. 61, pp.1638-43, 1984. 6. shay e.g.; ''diesel fuel from vegetable oils'', status and opportunities biomass bioenergy, vol.4, pp.227–242, 1993. 7. demirbas, a, ''comparison of transesterfication methods for production of biodiesel from vegetable oils and fats'', journal of energy conversion and management, vol.49, pp.125–30, 2008. 8. guru m., koca a., can o. , cınar c., sahin f., '' biodiesel production from waste chicken fat based sources and evaluation with mg based additive in a diesel engine", journal of renewable energy, vol.35, pp. 637–643, 2010. 9. dennis y.c., leung x. w., leung m.k.h., ''a review on biodiesel production using catalyzed transesterfication'', journal of applied energy, vol. 87, pp.10831095, 2010. 10. berrios m., martin m.a., chica a.f., martin a., ''study of esterification and transesterfication in biodiesel production from used frying oils in a closed system'', chemical engineering journal, vol.160 , pp.473-479, 2010. 11. vicente g.; martinez, m.; aracil j., '' optimization of integrated biodiesel production''. bioresour. technol., vol. 98, pp.1724-1733, 2007. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol. 24 no.1 (march 2023) 105 – 112 eissn: 2618-0707, pissn: 1997-4884 *corresponding author: name: nabaa s. alsaedy, email: n.hasoon1207@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. testing of a potentially used antiseptic consists of povidon iodine, hydrogen peroxide and aloe vera nabaa s. alsaedy a, *, raghad f. almilly a, and mohammad al-shannag b a chemical engineering department, college of engineering, university of baghdad, iraq b chemical engineering department, school of engineering, the university of jordan, jordan abstract in this study a new antiseptic was formulated and tested to match the effectiveness against microorganisms. the formulation consisted of povidone iodine (pvp-i) (10%), h2o2 (3%) and aloe vera gel (pure). different ratios of these materials were prepared within the acceptable range of ph for an antiseptic (3-6). the prepared samples were tested. the in vitro test was performed by using four bacteria, two were gram-positive (staphylococcus aureus and bacillus cereus) and two were gram-negative (escherichia coli and pseudomonas aeruginosa). the new antiseptic showed 100% killing rate for e. coli, ps. aeruginosa and s. aureus and 96.4667% killing rate for b. cereus. when the new antiseptic was compared with two common antiseptics (chloroxylenol (dettol) and alcoholbased antiseptic), it was superior because the alcoholic antiseptic showed 100% killing rate for e. coli, ps. aeruginosa and s. aureus and 89.8000% for b. cereus. the dettol did not show killing rate against bacteria. ex vivo test was carried out using the sample that showed the highest effectiveness in the in vitro test. this was performed by applying the formulation on the skin of lab mice after wounding and contaminating the wounds with two bacteria (staphylococcus aureus and escherichia coli). after applying the antiseptic on the wounds, swabs from the wounds were taken for testing. the new antiseptic showed amazing efficacy against bacteria by leaving agar dish completely empty from bacteria. in vivo test was also conducted using the polymerase chain reaction (pcr) test for covid-19. the new antiseptic did not show effectiveness against coronavirus because the virus could not be isolated like bacteria. keywords: aloe vera, antiseptic, ex vivo, hand hygiene, in vitro, in vivo, povidone iodine. received on 30/08/2022, received in revised form on 24/10/2022, accepted on 26/10/2022, published on 30/03/2023 https://doi.org/10.31699/ijcpe.2023.1.12 1introduction an antiseptic is a substance that stops or slows down the growth of microorganisms. hand hygiene is recommended by who guidelines, which includes frequent hand washing with soap and water for at least 20 seconds after using the restroom, before eating, and after coughing, sneezing, or blowing one's nose. the food and drug administration (fda) recommends sanitizing nonvisible soiled hands with an alcohol-based agent containing 80 percent v/v ethanol or 75 percent v/v isopropanol when soap and water are unavailable [1]. also, these guidelines published the activities of common used antiseptics and disinfectants with their mechanisms of action on different microorganisms, i.e. bacteria, viruses, fungi and spores. many of these known antiseptics have limitations in inactivating one or more of these kinds of microorganisms. others were found to be ineffective or harmful to humans like triclosan [2]. hand sanitization's success is entirely reliant on the use of effective hand disinfecting agents, which come in a variety of types and forms, including antimicrobial soaps, water-based and alcohol-based hand sanitizers [3]. alcohol is a common antiseptic due to its low cost and ease of production, but it appears to be less beneficial than pvp-i at killing bacteria [4]. povidone-iodine (pvp-i) is a well known alternative antiseptic to alcohol that is commonly used for skin antisepsis before and after surgery as well as in clinical settings. it is sometimes applied to the skin as a liquid or a powder and it may be used to treat instantaneous infections as well as preventing the spread of opportunistic diseases. povidone-iodine or betadine is polyvinylpyrrolidone-iodine (pvp-i) a chemical that is widely used as an antiseptic [5]. it consists of molecular iodine and polyvinylpyrrolidone that give it the yellowish-brown to reddish-brown colour. it is amorphous powder which has a characteristic odor. povidone-iodine has good solubility in water and in alcohol. it is applied on the skin and has a broad microbicidal spectrum against bacteria, viruses, fungi, yeasts, and protozoa [4]. there are ten possible aqueous iodine formulas only three of them have antimicrobial activity with molecular iodine be the most effective one. the formula that iodine takes in its aqueous solutions is greatly influenced by the ph of the medium. the presence of the acidic medium helps shift the reaction to form molecular iodine (i2) to become the dominant formula at low ph values [6]. according to the pharmacopoeia, ph of povidone-iodine must be between (1.5 5), but the optimal range is between (3-6). this range of ph is http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:n.hasoon1207@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2023.1.12 n. s. alsaedy et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 105 112 106 essential for obtaining the best efficacy of povidoneiodine, and also it ensures the stability of iodine in its complex, i.e. povidone-iodine [7]. the use of sterile aqueous iodine solutions may be accompanied with several problems such as weak solubility in water, chemical instability and potential local injury such as skin irritation. for overcoming all iodine problems, iodine carriers or what is known by iodophors emerged. they are polymers or large organic polymers complexed with iodine, cadexomer-iodine and povidone-iodine are the most commonly used of iodophors [8]. although the exact mechanism of the antisepsis effects of iodine is not fully understood, its capability in rapid penetration to the organism's cell wall and binding with proteins is a key factor in these effects. pvp-i has a wide antimicrobial spectrum. it is active against gram-positive and gramnegative bacteria as well as antibiotic-resistant and antiseptic-resistant strains so as fungi and protozoa. its activity extends to a broad range of enveloped and nonenveloped viruses moreover some bacterial spores if the time of exposure is increased. research has also shown iodine effectiveness in removing mycobacterium tuberculosis methicillin-resistant staphylococcus aureus (mrsa) [9, 10]. as a general rule, the effectivity of antiseptics increases, but the contact time required to reach maximum effectivity decreases as the applied concentrations increases provided other variables are held constants. studies conducted on pvp-i showed the bias of iodine complexes from this norm. in vitro studies monitored an increase in the amount of free molecular iodine in diluting the povidone-iodine solution (10%) [6]. basically, pvp-i is well tolerated by the majority of users, especially when applied to the skin [9]. in comparison to other antiseptics, pvp-i does not cause allergy or skin inflammation but anaphylactic and urticarial cases may occur very rarely. nevertheless, pvp-i may cause thyroid dysfunction with long-term use as mouthwash or gargle. although its safety for use does not lose its position, longterm patients using pvp-i should be monitored frequently [11]. hydrogen peroxide (h2o2) is commonly used for antisepsis, disinfection, and sterilization. it is a liquid of clear and colorless nature which is found commercially in different concentrations (3% 90%). hydrogen peroxide is regarded as a friendly ingredient for environment due to its rapid degradation to the safe terminals; water and oxygen. hydrogen peroxide proved broad-spectrum efficacy against bacteria, viruses, bacterial spores, and yeasts. in particular, hydrogen peroxide shows greater activity against gram-positive than gram-negative bacteria [8, 12]. the use of hydrogen peroxide-based disinfectants could reduce the concentrations of traditional disinfectants and therefore a reduction of their chemical residues in the environment after being used [12]. the synergistic effect of pvp-i and hydrogen peroxide was proved to have enhanced antimicrobial activity and may overcome acquired microbial resistance to single antiseptic [13]. it was shown that the addition of hydrogen peroxide to povidone-iodine significantly enhanced the effectiveness against plaque and gingivitis than using each product alone in an in vitro model [14]. also, recently, the combination of pvp-i and h2o2 proved its success in irrigation intraoperative wounds to inhibit the infection after spine surgery [15]. aloe vera is a medicinal plant traditionally used since 1500 bc in many countries such as greece, china, and mexico. it also has been used for centuries as a traditional medicine for various diseases and skin lesions. aloe vera is an indigenous plant from tropical madagascar, saudi arabia, and iran. it belongs to the liliaceae family; it is similar to cactus and is an herbaceous and perennial plant with thick, fleshy and long leaves [16]. aloe vera, has been used therapeutically for many centuries and is of particular interest due to its lengthy historic reputation as a curative agent and its widespread use in complementary therapies [16]. the inner, preserved gel is typically used as a health and nutrition supplement or in cosmetics and toiletries after the outer, green cuticle is removed. nevertheless, very few studies on this ingredient have been done; the majority have used whole leaf extracts. despite the fact that over 75 active ingredients, including vitamins, enzymes, minerals, lignin, saponins, sugars, sterols, amino acids, salicylic acid, and anthraquinones, have been identified from the inner gel, it has been challenging to link therapeutic benefits to specific active ingredients [17]. it contains over 70 biologically active compounds and is claimed to have anti-inflammatory, anti-oxidant, immune boosting, anticancer, healing, antiageing and anti-diabetic properties. aloes, by contrast, is an anthraquinone derivative of the sap of the aloe leaf which has been used for centuries as a purgative [18]. the antibacterial activities of a. vera were dependent on the dose of anthraquinone. it is reported that a. vera possesses antifungal, antiviral, antibacterial and acaricidal activity against skin infections such as acne, herpes and scabies [19]. european committee for standardization (cen) and food and drug administration (fda) are the most known protocols for testing hand hygiene [20]. the tests include the following steps: in vitro tests include testing of suspension, drawing time kill curves as well as determining the minimum inhibitory concentrations (mic) to assess the activity against microbes of hand antiseptics which provide just an exploratory reference of the agents' effect spectrum and speed up of activity. ex vivo tests include testing the formulation on animal's skin or human's. applying the human skin temperature and times of contact may reflect real cases and represent clearer reference that hand sanitizer is able to treat microorganisms that transmit by hand. it requires testing of hands in the real field for levels of skin contamination with microbes before and after applying the formulation. in vivo test is conducted directly on human hands following a certified protocol that simulates very nearly the conditions of using antiseptic in the field which may be followed up by clinical trials. using these protocols helps to obtain important knowledge n. s. alsaedy et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 105 112 107 about the activity of a hand sanitizer to cross the diffusion of microbes carried by hands in healthcare environment [20]. these tests based on two main procedures. the first is prepared to assess the hand-rub or the hand-wash formulations' ability to remove transitory microorganisms from the hands of hcws. this method uses the postcontamination treatment of hands by placing the organism(s) of the test on volunteers' hands then exposing them to the antiseptic. this procedure is important in evaluating the formulations applied in frequent hand sanitization. the second method is conducted especially to the cases of pre-surgery and the purpose is to assess the tested antiseptic's capability to eliminate the inhabitant microbes on the hands [20]. in the present outbreak of covid-19, searching for an effective hand antiseptic becomes a persistent need all over the world. since the declaration of covid-19 as a pandemic on late 2020, the world health organization (who) and national disease control agencies have repeatedly emphasized the importance of hand hygiene in preventing the spread of the virus. in this respect a study was done to formulate a new antiseptic that met the basic demand of effectiveness against a broader spectrum of microorganisms. the novelty of this work is the formulation of pvp-i, h2o2 and aloe vera for the first time to prepare hand sanitizer. 2experimental work 2.1. materials and chemicals all materials and chemicals that have been used are listed in table 1. table 1. materials and chemicals used in the research material name chemical formula purity manufacturer company country of manufacture povidone iodine c6h9i2no 10% aqua company turkey hydrogen peroxide h2o2 3% chemical lab company belgium aloe vera pure plant nursery iraq 2.2. equipment all equipment and devices that were used in the research and their specifications are listed in table 2. in addition, laboratory glassware (beaker, cylinder, funnel) were also used. table 2. specifications of equipment and devices used in the research equipment name specifications manufacturer company country of manufacture magnetic stirrer 0 1400 rpm heidolph germany ph meter 0 – 14 hm digital usa blender 0-23000 rpm pioneer japan 2.3. procedure 2.3.1. aloe vera preparation based on what was mentioned in the method of preparing aloe vera [21]. the following method was applied. using cold water to wash the aloe vera leaves. each leaf should have the top and bottom cut off with a large, sharp knife, then discarded. cutting the leaf in half lengthwise to create two equal-sized pieces. after that, removing the green skin by cutting along the aloe vera gel and the skin with a sharp knife. cutting the aloe vera gel and discarding the skin. then it was mixed with a blender at 23000 rpm for 10 min and then filtered. 2.3.2. formulation preparation nine samples were prepared by mixing pvp-i, hydrogen peroxide and aloe vera in different ratios. table 3 shows the specifications of samples. the acidity function, ph, was monitored in the prepared samples to be within the suitable range for living tissue (3-6) [6]. nine samples were prepared within the acceptable range of ph. 2.3.3. testing ain vitro testing the samples were tested in food research center lab./ department of environmental and water treatment / iraqi ministry of science and technology. four kinds of bacteria were selected based on their prevalence in hospitals and health centers. two were gram-positive; staphylococcus aureus and bacillus cereus and two were gram-negative; escherichia coli and pseudomonas aeruginosa. the laboratory results showed the number of remaining bacteria after treating with the samples. the killing rate were calculated according to the following equation: % kill rate = ((control – residual))/control*%100 (1) bex vivo testing the best samples which showed maximum killing rate in the in vitro test (samples 6 and 7) were directed forward to ex vivo testing. after getting the necessary approvals, the test was done at the biotechnology research center / al-nahrain university where the experiments were carried out in a laboratory setting right away. this test was applied on animal skin, specifically on the skin of laboratory mice, according to the following procedure. two types of bacteria were selected and cultivate, gram-positive (staphylococcus aureus) and gram-negative (pseudomonas aeruginosa). four mice n. s. alsaedy et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 105 112 108 were isolated and ensured their safety. an area of mouse skin was sterilized and cleaned with a razor. small cuts on the skin were made with a razor, then the wound was contaminated with the prepared bacteria, two mice were contaminated with one type of bacteria. they were left for 24 hours. after that the wound was sterilized with the samples. two mice were sterilized with the sample 6 (3: 1: 1) and the other two were sterilized with the sample 7 (1: 1: 3) and left for 10 minutes. then swabs were taken from the skin after sterilization, and examined in the laboratory. cin vivo test this test was accomplished at istishari medical laboratory / yarmouk / baghdad. istishari medical lab is a subsidiary of asco group holding and a joint venture with iraqi ministry of health and environment. in the department of medical and people's clinics, positive swabs of coronavirus were collected from infected people and used in the pcr test. the pcr test for covid-19 is a molecular test that looks for genetic material (ribonucleic acid or rna) of sarscov-2, the virus that causes covid-19 in a respiratory specimen. in pcr test, small amounts of rna from specimens were intensified to create dna. if the rna contains signs of sars-cov-2, the replication process will continue until the virus is detected. since february 2020, the pcr test has served as the accepted standard for diagnostics covid-19 due to its precision and dependability [22]. table 3. different samples prepared in the study sample constituents ratio (pvp-i:h2o2:a.vera) ph povidone-iodine volume (ml) h2o2 volume (ml) aloe vera volume (ml) 1 1:0.5:1 4.15 20 10 20 2 1:1:1 3.47 20 20 20 3 1:2:1 3.45 20 40 20 4 2:1:1 5.33 20 10 10 5 1:1:2 5.02 10 10 20 6 3:1:1 5.32 30 10 10 7 1:1:3 4.88 10 10 30 8 1:1.5:1 4.77 10 15 10 9 1.5:1:1.5 5.03 15 10 15 3results and discussion 3.1. in vitro test the in vitro test was performed on the nine prepared samples as well as dettol and an alcohol-based sanitizer for comparison. fig. 1 shows the effect of varying povidone-iodine concentration on the effectiveness of the samples against bacteria. it was noticed that reducing povidone-iodine in the sample enhanced its efficacy, such as the points 10 and 15 ml volume which showed high kill rate (85-100%) for the four bacteria. this was in agreement with the findings of previous researches [6, 10]. pvp-i also showed high efficacy (100%), but not for all bacteria, at 30 ml volume. this result might be reached due to the synergistic effect of h2o2 [13]. fig. 2 shows the effect of aloe vera concentration on the biocide effect of the samples. increasing aloe vera extract concentration in the sample lowered its efficacy as for pvp-i. the sample showed high kill rate for all bacteria at 10 and 15 ml of aloe vera in the sample but it showed high kill rate not for all bacteria at 30 ml point. this was in agreement with the finding of a previous research [16] that aloe vera can be used as a complementary treatment alongside other methods. fig. 3 clarifies the effect of changing hydrogen peroxide concentration on the effectiveness of the samples. it was clear that hydrogen peroxide was effective approximately at all concentrations studied in this research. the essence of hydrogen peroxide activity against microorganisms based on its capability of oxidizing these microorganisms and converting to oxygen and water. the oxidation process includes destroying the cell wall of these microorganisms. at 30 ml volume, the kill rate was 100% for all bacteria. at less or more than this volume, the kill rate was approximately 100% but not for all bacteria. it did not show the same efficacy on all bacteria because some kinds of bacteria have enzymes like lactoperoxidase (lp) which catalyzes the oxidation reaction producing a weak oxidizing agent of h2o2 which has bacteriostatic activity [23]. this was in agreement with other research [12]. for medical applications (3-9%) is recommended [2]. fig. 1. the effect of different amounts of povidone iodine on the effectiveness of the samples against the four types of bacteria (in vitro test) h2o2 activity is a time-dependent loss of viability. the concentration of h2o2 required to kill half the bacteria n. s. alsaedy et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 105 112 109 within 15 s is 1.8 m (6%) but fall to 0.3 m (1%) at 2 min, to 10 mm (0.03%) at 1 h, and to 0.2 mm (0.0007%) with a 24-h exposure [23]. nevertheless, it was noticed that hydrogen peroxide boosted the effectiveness of the sample at all volumes used. although the effect of time on the sample was not studied in the present work but it could be reached to the following conclusion based on the literature. as mentioned later that h2o2 lose its efficacy with time as a result of continual dilution. this occurs when it exists in the solution alone. the existence of pvp-i with h2o2 in the solution resurge the efficacy by liberating molecular iodine continuously in the diluted solution as mentioned previously. the acidity function, ph of the prepared samples was within the acceptable range for an antiseptic (3-6) [6] i.e. in the acid range, therefore; its effect was not studied. fig. 4 shows the agar dishes after the application of these samples. the dishes were clear from the studied bacteria (s. aureus, e. coli, ps. aeruginosa, and b. cereus). fig. 5 shows a comparison among sample 6, dettol and alcoholic sanitizer against the studied bacteria. the sample was superior to dettol and alcoholic sanitizer against all studied bacteria. fig. 2. the effect of different amounts of aloe vera on the effectiveness of the samples against the four types of bacteria (in vitro test) fig. 3. the effect of different amounts of hydrogen peroxide on the effectiveness of the samples against the four types of bacteria (in vitro test) 3.2. ex vivo test samples 6 and 7 were further investigated by ex vivo testing. first they were tested by visual observation on the skin of four mice after applying them on the mice's skin. it was observed that no skin sensitivity or redness occurred. the second step was done on the same mice by injuring them and contaminating the wound with two bacteria; staphylococcus aureus and escherichia coli. two mice were contaminated with each bacteria. after 24 hours the wound became infected then the wound was sterilized with both samples. finally, swabs were taken from the wounds, culturing and examining them in the laboratory. after applying the laboratory test on the samples, it was noticed that the agar dishes were completely empty from any bacteria as shown in fig. 6 with each examination duplicated. this indicated that the prepared antiseptic had excellent effectiveness. fig. 4. agar dishes after in vitro test for samples 6 and 7 in addition to alcoholic sanitizer and dettol. samples dishes were completely empty from bacteria fig. 5. comparison between sample 6 (3:1:1), dettol and alcoholic sanitizer applied on the four kinds of bacteria (in vitro test) n. s. alsaedy et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 105 112 110 3.3. in vivo test for in vivo test application on formulation samples 6 and 7, ten samples of positive swabs of covid-19 were tested in pcr test. for every test there were two results for hex and fam wavelengths of fluorescence which represent y-axis. the thermal cycle represents the x-axis and the line parallel to the x-axis represents the point at which fluorescence is measurable. the existence of corona rna series was clear as shown in fig. 7. sample 6 and 7 showed ineffectiveness against covid-19 virus. pcr test depended on extracting rna from the virus cell and this was not compatible with the mechanism of iodine activity. one of the iodine mechanisms of action against microorganisms is by disrupting the cell wall of them leading to cytosol leakage [4]. and this cannot be detected by the pcr test. fig. 6. agar dishes after ex vivo test of the samples 6 and 7 were empty from bacteria fig. 7. pcr test of (a) hex wavelength and (b) fam wavelength 4conclusions a new antiseptic was prepared from pvp-i (10%), h2o2 (3%) and pure aloe vera in different ratios of these constituents depending on ph to be within the acceptable range for an antiseptic. the effect of each constituent was studied in detail and the results confirmed that each one of them was influential in the antiseptic's effectiveness. the new antiseptic was investigated by in vitro test on four bacteria (staphylococcus aureus and bacillus cereus) as gram-positive type and (escherichia coli and pseudomonas aeruginosa as gram-negative. four samples (samples 6, 7, 8 and 9) showed excellent efficacy in killing bacteria in comparison with alcoholic antiseptic and chloroxylenol (dettol). these samples have the ratios of pvp-i: hydrogen peroxide: aloe vera: 3:1:1, 1:1:3, 1:1.5:1 and 1.5:1:1.5, respectively. ex vivo test was conducted on four lab mice using samples 6 and 7. the prepared samples showed an excellent efficacy in these tests. also, the antiseptic was tested by pcr test against coronavirus but the test could not demonstrate the effectiveness of the new antiseptic and another in vivo test should be consulted. (a) (b) n. s. alsaedy et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 105 112 111 references [1] d. singh, a. agusti, a. anzueto, p.j. barnes, j. bourbeau, b.r. celli, g.j. criner, p. frith, d.m.g. halpi, m. han, m.v.l. varela, f. martinez, de oca m. montes, a. papi, i.d. pavord, n. roche, d.d. sin, r. stockle, j. vestbo, j.a. wedzicha and c. vogelmeier, global strategy for the diagnosis, management, and prevention of chronic obstructive lung disease: the gold science committee report 2019, copd: gold science committee report 2019. eur respir j, 53, 2019, http://doi.org/10.1183/13993003.00164-2019. [2] g. mcdonnell and a.d. russell, antiseptics and disinfectants: activity, action, and resistance, clinical microbiology reviews 12, 147-179, 1999, https://doi.org/10.1128/cmr.12.1.147. [3] j.l. jing, th. p. yi, r.j. bose, j.r. mccarthy, n. tharmalingam and th. madheswaran, hand sanitizers: a review on formulation aspects, adverse effects, and regulations, int. j. environ. res. public health 17, 1-17, 2020, https://doi.org/10.3390/ijerph17093326. [4] m. eggers, infectious disease management and control with povidone iodine, infect dis ther, 8, 581–593, 2019, https://doi.org/10.1007/s40121-01900260-x. [5] n.h. risso, c.d.o. stopiglia, m.t. oliveira, s.e. haas, t.r. maciel, n.r. lazzari, e.l. kelmer, j.a.p. vilela, d.v. beckmann, chlorhexidine nanoemulsion: a new antiseptic formulation, int. j. nanomedicine, 15, 6935–6944, 2022, http://doi.org/10.2147/ijn.s228280. [6] n. moussa, control and evaluation of the antiseptic activity of common povidone-iodine solutions in the market, m.sc. thesis, tishreen university, syria, 2016. [7] s. kumar, r. babu, j. reddy and a. uttam, povidone iodine –revisited, indian journal of dental advancements, 3, 617-620, 2011, http://doi.org/10.5866/3.3.617. [8] r.g. sibbald, d.j. leaper and d. queen, iodine made easy, wounds international, 2, 1-6, 2011. [9] t. yasuda, s. yoshimura and y. katsuno, comparison of bactericidal activities of various disinfectants against methicillin-sensitive staphylococcus aureus and methicillin-resistant staphylococcus aureus, postgraduate medical journal, 69, 66–69, 1993. [10] d. lepelletier, j.y. maillard, b. pozzetto and a. simon, povidone iodine: properties, mechanisms of action, and role in infection control and staphylococcus aureus decolonization, antimicrob agents chemother, 64, 2020, https://doi.org/10.1128/aac.00682-20. [11] m. eggers, m. eickmann and j. zorn, rapid and effective virucidal activity of povidone-iodine products against middle east respiratory syndrome coronavirus (mers-cov) and modified vaccinia virus ankara (mva), infect dis ther, 4, 491–501, 2015, https://doi.org/10.1007/s40121-015-0091-9. [12] a.g. ríos-castillo, f. gonzález-rivas and j.j. rodríguez-jerez, bactericidal efficacy of hydrogen peroxide-based disinfectants against gram-positive and gram-negative bacteria on stainless steel surfaces, food microbiology & safety, 8, 2017, https://doi.org/10.1111/1750-3841.13790. [13] e.i. zubko and k.m. zubko, co-operative inhibitory effects of hydrogen peroxide and iodine against bacterial and yeast species, bmc research notes 6, 17, 2013, https://doi.org/10.1186/1756-0500-6-272. [14] j. maruniak, w.b. clark, c.b. walker, i. magnusson, r.g. marks, m. taylor and b. clouser, the effect of 3 mouthrinses on plaque and gingivitis development, j clin feriodontol, 19, 19-23, 1992, https://doi.org/10.1111/j.1600-051x.1992.tb01143.x. [15] g. arakeri and p.a. brennan, povidone-iodine and hydrogen peroxide mixture soaked gauze pack: a novel hemostatic technique, journal of oral and maxillofacial surgery, 71, 1833e1-1833e3, 2013, http://doi.org/10.1016/j.joms.2013.07.025. [16] d. hekmatpou, f. mehrabi, k. rahzani, a. aminiyan, the effect of aloe vera clinical trials on prevention and healing of skin wound: a systematic review, iran j med sci., 44, 1–9, 2019. [17] a. bashir, b. saeed, t.y. mujahid and n. jehan, comparative study of antimicrobial activities of aloe vera extracts and antibiotics against isolates from skin infections, african journal of biotechnology, 10, 3835-3840, 2011, http://doi.org/10.5897/ajb07.572. [18] l. langmead, r.m. feakins, s. goldthorpe, h. holt, e. tsironi, a. de silva, d.p. jewell, d.s. rampton, randomized, double-blind, placebo-controlled trial of oral aloe vera gel for active ulcerative colitis, alimentary pharmacology & therapeutics, 19, 739747, 2004, https://doi.org/10.1111/j.13652036.2004.01902.x. [19] d. mantle, m.a. gok, t.w.j. lennard, adverse drug reactions and toxicological reviews, 20, 89-103, 2001. [20] m. rotter, s. sattar, s. dharan, b. allegranzi, e. mathai and d. pittet, methods to evaluate the microbicidal activities of hand-rub and hand-wash agents, journal of hospital infection, 1-9, 2009, https://doi.org/10.1016/j.jhin.2009.06.024. [21] r.h. maret, process for preparing extracts of aloe vera, us patent, 1975. [22] understanding covid-19 pcr testing, national human genome research institute, 2022. [23] e.l. thomas, t.w. milligan, r.e. joyner and m.m. jefferson, antibacterial activity of hydrogen peroxide and the lactoperoxidase-hydrogen peroxide-thiocyanate system against oral streptococci, infection and immunity, 529-535, 1994, https://doi.org/10.1128/iai.62.2.529-535.1994. http://doi.org/10.1183/13993003.00164-2019 https://doi.org/10.1128/cmr.12.1.147 https://doi.org/10.3390/ijerph17093326 https://doi.org/10.2147/ijn.s228280 https://europepmc.org/article/med/8290461 https://europepmc.org/article/med/8290461 https://europepmc.org/article/med/8290461 https://europepmc.org/article/med/8290461 https://europepmc.org/article/med/8290461 https://europepmc.org/article/med/8290461 https://doi.org/10.1128/aac.00682-20 https://doi.org/10.1111/1750-3841.13790 https://doi.org/10.1111/j.1600-051x.1992.tb01143.x https://www.ncbi.nlm.nih.gov/pmc/articles/pmc6330525/ https://www.ncbi.nlm.nih.gov/pmc/articles/pmc6330525/ https://www.ncbi.nlm.nih.gov/pmc/articles/pmc6330525/ https://www.ncbi.nlm.nih.gov/pmc/articles/pmc6330525/ https://doi.org/10.1111/j.1365-2036.2004.01902.x https://doi.org/10.1111/j.1365-2036.2004.01902.x https://doi.org/10.1016/j.jhin.2009.06.024 https://patents.google.com/patent/us3878197a/en https://patents.google.com/patent/us3878197a/en https://doi.org/10.1128/iai.62.2.529-535.1994 n. s. alsaedy et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 105 112 112 ين بيروكسيد الهيدروج اختبار مطهر يد محتمل االستخدام يتالف من بوفيدون اليود, وااللوفيرا 2ومحمد الشناق ،1 د فريــد الملــيــرغ ،* ،1 نبــأ سعيــد حســون ، العراقجامعة بغدادكلية الهندسة، ، قسم الهندسة الكيمياوية 1 قسم الهندسة الكيمياوية، كلية الهندسة، جامعة االردن، االردن 2 الخالصة واختباره لمطابقة فعاليته ضد الكائنات الحية الدقيقة. يتكون ، تمت صياغة مطهر جديد في هذه الدراسة وهالم الصبار )نقي(. تم تحضير نسب %3 )i-pvp( 10 ٪)2o2h (يود -المستحضر من بوفيدون اختبرت النماذج التي .(6-3بالنسبة لمطهر اليد ) phضمن الحدود المسموح بها من مختلفة من هذه المواد ، اثنان منها موجبة الجرام )من البكتيريا باستخدام أربعة (in vitroإجراء االختبار في المختبر)تم تحضيرها. تم staphylococcus aureus( و) bacillus cereusواثنان سالبة الجرام )) escherichia coli) و (pseudomonas aeruginosa) نسبة قتل لكل من %100أظهر المطهر الجديدescherichia coli، pseudomonas aeruginosa و staphylococcus aureusنسبة قتل ل %96.466وbacillus cereus. عند مقارنة المطهر الجديد مع مطهرين شائعين )كلوروكسيلينول )ديتول( ومطهر يحتوي على ،escherichia coliلكل من %100الن المطهر الكحولي أظهر نسبة قتل الكحول( كان متفوقا pseudomonas aeruginosa و staphylococcus aureus ل %89,8000وbacillus cereus . باستخدام العينة التي (ex vivo)تم إجراء اختبار خارج الجسم الحيلم يظهر الديتول نسبة قتل ضد البكنريا. جلد فئران . تم إجراء ذلك عن طريق وضع المستحضر على (in vitro)أظهرت أعلى فعالية في اختبار escherichia)و (staphylococcus aureus) التجارب بعد إصابة الجروح وتلويثها بنوعين من البكتيريا coli). تم أخذ مسحات من الجروح لفحصها. أظهر المطهر الجديد فعالية بعد وضع المطهر على الجروح ، (vivo inم إجراء اختبار في الجسم الحي ). تباق اكر خالية تماما من البكتريابترك أط مذهلة ضد البكتيريا المطهر الجديد لم يظهر فاعلية ضد .covid-19 لـ (pcr) أيًضا باستخدام اختبار تفاعل البلمرة المتسلسل فيروس كورونا ألنه اليمكن عزل الفايروس كما في البكتريا. .اليود –، داخل الجسم الحي، بوفيدون الجسم الحي، نظافة اليدين، في المختبر، خارج ة: الصبار، المطهردالالكلمات ال available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.20 no.4 (december 2019) 61 – 66 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: halah m. hussain , email: hala_muhammed@gmail.com , name: abdulhaleem a.k. mohammed, email: prof.abdullhaleem@gmail.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. experimental study of iraqi light naphtha isomerization over ni-pt/h-mordenite halah m. hussain and abdulhaleem a.k. mohammed alfaraby university college / baghdad-iraq abstract hydroisomerization of iraqi light naphtha was studied on prepared ni-pt/h-mordenite catalyst at a temperature range of 220300°c, hydrogen to hydrocarbon molar ratio of 3.7, liquid hourly space velocity (lhsv) 1 hr -1 and at atmospheric pressure. the result shows that the hydrisomerization of light naphtha increases with the increase in reaction temperature at constant lhsv. however, above 270 0 c the isomers formation decreases and the reaction is shifted towards the hydrocracking reaction, a higher octane number of naphtha was formed at 270 °c. keywords: iraqi light naphtha isomerization, nickel-platinum over h-mordenite. received on 09/02/2019, accepted on 03/04/2019, published on 30/12/1029 https://doi.org/10.31699/ijcpe.2019.4.10 1introduction the utilization of an upgraded low-value refinery stream to the gasoline pool might present a solution to the problem, as it can considerably lower the cost of gasoline production, while loses only some of its original quality, but still remains environmentally friendly. the use of bifunctional zeolite catalysts specifically designed to enhance the octane number of light nuphtha through the hydroisomerization process has already been marketed.[1]. however, this application has not yet been commercially extended to include the treatment of heavy naphtha, which usually contains normal alkanes from the heptane range to decane [2]. isomerization, cracking and alkylation are acid-induced reactions. the catalyzad hydrocarbon reactions are of great importance nowadays and it is not surprising that many studies have been devoted to this subject. however, important questions remain regarding the mechanism and effect of catalytic pore structure on the activity and selectivity to answer. [3]. isomerization of n-paraffin to branched paraffin is important in petroleum refining industry for improving motor fuels properties such as high gasoline octane number [4], diesel fuel with high cetane number, low pour point and high viscosity index. to accomplish high isomerization selectivity; balance between the active component (metal) and acid functions is needed [5]. more studies about isomerization to produce high quality gasoline such as vaudagna, [6] indicated that loading of pt on wo3/zro2 have positive effect on the rate and selectivity of alkanes isomerisation in the presence of hydrogen. the pt metal was impregnated into the wo3/zro2, so that the catalysts contain 0.4wt. % of pt and the pt/ wo3/zro2 calcined to a temperature of 830 0 c (at 20 c min -1 ) for 3 hours. the specific surface area was found to increase to more than 350m 2 /g. al-hassany m. [7] studied that light naphtha treatment achieved over 0.3wt%pt loaded-alumina, hy-zeolite and zr/w/hy-zeolite catalysts at temperature range of 240370 °c, hydrogen to hydrocarbon mole ratio of 1-4 with liquid hourly space velocity (lhsv) 0.75-3 hr -1 , and at atmospheric pressure. results showed that pt/zr/w/hy is the best catalyst for producing isoparffines due to its higher acidity compared with pt/hy. the pt/zr/w/hy catalyst showed lower activity for aromatization of naphtha to cyclopareffins and benzene selectivity than pt/hy. a smaller pore volume leads to lower aromatization activity and higher isomerization and cracking activity. the maximum isoparaffins extent was achieved and reached 78% at 300 °c and lhsv of 0.75 hr -1 on pt/zr/hy and aromatics extent was reached 10% at 370 °c and lhsv of 0.75 hr -1 on pt/ hy. al-saraj m a a. et al. [8] studied light naphtha isomerization over 0.3wt. % pt / hmor was the catalyst. the operating condition was performed for all temperature experiments from 200 to 350 ° c, pressure range from 3 to 15 bar, lhsv range from 0.5-2.5hr -1 , and from hydrogen to naphtha a ratio of 300. the results show that the isomerization of the iraqi light naphtha increases with increasing reaction temperature and decreases with an increase in lhsv. high research octane number (93)was formed at 240 ° c. https://doi.org/10.31699/ijcpe.2019.4.10 h. m. hussain and a. a.k. mohammed / iraqi journal of chemical and petroleum engineering 20,4 (2019) 61 66 26 in this work the catalytic activity of the promoted prepared catalyst (pt-ni/h-mordenite) using light naphtha isomerization was studied at different operating conditions and the chemical composition of produced gasoline using pona analysis was determined. 2experimental work 2.1. materials a. feedstock iraqi light naphtha supplied from al-dora refinery was used as a feedstock in hydroisomerization experiments. the physical properties and pona analysis of iraqi light naphtha are listed in table 1. table 1. physical properties and pona analysis of iraqi light naphtha physical proprties value specific gravity at 60 0 /60 0 f 0.6631 api gravity 80.6 kinematic viscosity at 25 0 c, m 2 /s 7.2*10 -7 research octane number 60 sulfur content ppm 1.5 chemical composition wt.% n-paraffin 42.9 i-paraffin 42.1 olefin 0.3 naphthene 9.1 aromatic 5 b. chemicals the chemicals used for experimental work are tabulated in table 2. table 2. the chemicals used for experimental work chemical source(company) purity sodium hydroxide alpha chemika 99% sulfuric acid sigma aldrich 98% sodium aluminate sigma aldrich 50-56% ammonium chloride bdh limited pool, england 99% nickel nitrate himedia, india 97% cloro platinic acid sigma aldrich 40% hydrogen gas al-dura power station 99% nitrogen gas al-khalej plant 99% 2.2. synthesis of na-mordenite (na-mor) na-mor was synthesized from nano-silica. 38. 90 g of naoh was dissolved in 249.3 ml of water and then divided into two equal portions. in one portion, 5.56 g of nano-silica was completely dissolved. to the other portion, 10.19 g of naalo2 was added to prepare a clear aluminate solution. then the silicate solution was slowly poured into the aluminate solution with vigorous stirring, and a homogenous gel resulted. the resultant gel was stored in a water bath at room temperature (t =25 ± 2°c), in a sealed poly tetra fluoro ethylene (ptfe) bottle under stirrer at 250 rpm for 3 days at ph 14. the solid product was separated by filtration (whatman no. 41 filter paper) using a buckner funnel with the aid of a vacuum pump, then washed more times by distilled water until the ph value dropped to 8.69. the product was left at room temperature overnight, dried at 110°c for 2 hr and calcined at 400 0 c for 2 hr. [9]. 2.3. synthesis of h-mordenite (h-mor) the hydrogen form of zeolite h-mor was obtained from na-mor exchange with a solution of 4 n nh4cl. zeolite na-mor was slurred in an ammonium chloride solutions with mixing at 70 o c for 2 hr and then left at room temperature overnight for ion exchange completion. after that the exchanged zeolite was filtered off, washed with distilled water. the product was left at room temperature overnight, dried at 110 0 c for 2 hr and calcined at 400 0 c for 2 hr. [10] 2.4. preparation of ni-pt/h-mor by impregnation method 100g of h-mor-zeolite as a powder was mixed with 10 wt. % bentonite clay as binder. the resulting mixture was mixed with water to form a paste. extrudates with 3-7 mm were formulated and dried over night at 110 º c and then calcined at 400 0 c for 2 hr. to prepare 0.15wt % of pt on 50 g of h-mor pellets the carrier catalyst h-mor was dried at 110 º c with air for two hours and placed in impregnation under vacuum, then the solution of chloroplatinic acid (0.205 g h2ptcl6 and 30 ml deionized water) was added drop by drop under magnetic stirring then the vacuum cut off and the sample left under mixing for about 2 hr to have a homogenous distribution of metal precursors. the product was slurry filter washed with distilled water, dried at 110 o c overnight and calcined at 400 o c for two hours at a rate of 2ºc /min [11]. after calcination the catalyst was reduced by hydrogen at 350 º c for 3 hours. for preoare ni-pt/hmor catalyst containing 0.215 wt. % of ni, 50 g of pt/hmor was impregnated with 0.2 m ni (no3)2.2h2o aqueous solution at 40 0 c for 2 hours. the obtained filtrated, dried and calcined at 400 0 c for 2 hours. 2.5. catalytic activity test the catalytic activity test was achieved in a continuous flow at fixed-bed reactor. figure 1 shows the process flow diagram of unit. 30 g ni-pt/h-mor was charged to the reactor between two layers of inert ceramic particles. the platinum containing catalyst was reduced with h2 at 350°c for 3 hr. the catalytic reaction was carried out with lhsv of 1 hr -1 , at temperature range of 220-300°c, hydrogen to feed mole ratio of 3.7 and at atmospheric pressure. the reactor was flushed with nitrogen to purge the air from the system. h. m. hussain and a. a.k. mohammed / iraqi journal of chemical and petroleum engineering 20,4 (2019) 61 66 26 meanwhile, the reactor is heated to the desired temperature. after reaching the reaction temperature, the nitrogen valve was closed. a pre-specified flow rate of light naphtha was set on. vaporization of the feed occurs in the evaporator. the vapor of light naphtha was mixed with specified flow rate of hydrogen in the mixing section. the mixture entered the reactor from the top, and reacted on the surface of catalyst. the final condensed product was collected only after steady state operation was established while initial products were discarded. fig. 1. process flow diagram of the catalytic experimental unit 3results and discussion 3.1 characterization of na-mor and h-mor. a. xrd analysis fig. 2 shows that the x-ray diffraction patterns of synthesized na-mor. these crystal was similar to that obtained by r. szostak [12] and m. mohamed et al, [13]. this means that the synthesized sample is na-mor crystals. fig. 2. x-ray powder pattern of prepared na-mor zeolite the exchange technique was used in this work is one step impregnation under a constant temperature to convert na-mor zeolite to h-mor zeolite. fig. 3, illustrates the xrd patterns of the synthesized zeolite h-mor. xrd phase is found to match with the show peaks at 2θ = 6.57, 9.77, 19.65, 22.36, 25.72 and 26.36. these peaks are characteristic for h-mor zeolite. it can be seen from figure 4, that the synthesized sample showed the formation of h-mor phase [13]. the relative crystnality of h-mor was calculated by equation 1 and it was 118 %. relative crystnality of zeolite= sx/sy *100 (1) where: sx = sum of integral peak intensities for the prepared catalyst. sy = sum of integral peak intensities for the standard catalyst. fig. 3. x-ray powder pattern of prepared h-mor zeolite b. surface area and pore distribution analysis h-mor was characterized using n2 sorption to determine their surface area and pore volume. surface area and pore volume depend mainly on the structure of the solid. it was found that the bet surface area and pore size of h-mor were 336.7 m 2 /g and 2.49 nm, respectively. the surface area obtained in this work was higher than those obtained by hisham m. et al, (52.14 m 2 /g) [14] and heman et al, (254.38 m 2 /g) [15]. 3.2. isomerization conversion isomerization conversion was determined by equation 2, while percentage decreasing of naphthenic and aromatic calculation by equation 3. * 100% (2) * 100% (3) 0 200 400 600 800 1000 1200 1400 1600 5 10 15 20 25 30 35 40 45 50 55 60 in t e n c it y 2 theta h. m. hussain and a. a.k. mohammed / iraqi journal of chemical and petroleum engineering 20,4 (2019) 61 66 26 table 3 shows the chemical composition of produced gasoline using pona analysis in order to evaluate the catalyst performance. the hydroconversion involves three main reactions hydroisomerization, dealkylation and hydrogenation. table 3. pona analysis for isomerization of iraqi light naphtha at lhsv = 1 hr -1 and different t t 0 c wt. % 220 0 c 240 0 c 270 0 c 300 0 c n-paraffin 29.4 28.1 26.1 28 i-paraffin 57.2 62.7 65.2 62.7 olefin 0.2 0.2 0.2 naphthen 8.7 5.8 5.4 5.8 aromatic 4.7 3.2 3.1 3.3 fig. 4 shows the effect of temperature on the isomerization reaction. the isomerization conversion, as shown in this figure, increases with temperature increasing up to 270 0 c. this is due to n-paraffin isomerization. this agrees with an investigation reported by mohammed et al, [8] and maha h. [7] obtained for hydroisomerization light naphtha using pt-ni/h-mordenite. furthermore, the lower reaction temperature increases the percentage of branch alkane at thermodynamic equilibrium as mentioned by fahim m a et al. [16]. fig. 4. effect of temperature on isomerizate conversion of iraqi light naphtha on pt-ni/h-mordenite catalyst at lhsv = 1 hr -1 fig. 5 and fig. 6 show the relationship between percentage change of naphthene and aromatic with temperature, respectively. the increasing of temperature firstly, promote aromatic hydrogenation to cyclo-paraffin and cyclo-paraffin hydroisomerization to iso-paraffin and secondly, higher temperature change the thermodynamic equilibrium forward decreasing hydroisomerization as mentioned by al-hassany m. [7] at different temperature 220-300 0 c , constant lhsv = 1 hr -1 and h2/hydrocarbon mole ratio = 3.7 fig. 5. effect of temperature on naphthene percent decreas of iraqi light naphtha on pt-ni/h-mordenite catalyst at lhsv = 1 hr -1 fig. 6. effect of temperature on aromatic percent decrease of iraqi light naphtha on pt-ni/h-mordenite catalyst at lhsv = 1 hr -1 fig. 7 shows the octane number of produced light naphtha at different temperature. this figure shows that the octane number of produced light naphtha (isomerization) more higher than the light naphtha (ron = 60) and the maximum octane number (92) obtained at 270 0 c. the isomeizate obtained at 270 0 c can be easy used as high octane component for producer lead free automobile gasoline. fig. 7. the highr of temperature on the ron at lhsv 1 hr -1 30 40 50 60 200 220 240 260 280 300 320 is o m e ri za te c o n ve rs io n w t. % temperature 0c 0 10 20 30 40 50 200 220 240 260 280 300 320 n a p h th e n e p e rc e n t d e cr e a se s w t. % temperature 0c 5 10 15 20 25 30 35 40 45 200 220 240 260 280 300 320a ro m a ti c p e rc e n t d e cr e a se s w t. % temperature 0c 76 78 80 82 84 86 88 90 92 94 200 250 300 350 r o n tempreature 0c h. m. hussain and a. a.k. mohammed / iraqi journal of chemical and petroleum engineering 20,4 (2019) 61 66 26 4conclusions the prepared catalyst ni-pt/h-mordenite exhibits a high hydroisomerization activity within the studied range of operating conditions. the hydroisomerization reaction is temperature dependent, and the lower temperature the greater hydrosiomerization selectivity and in turn high ron value. the isomerizate at 270 0 c and lhsv = 1 hr -1 has ron = 92 and can be used as component for lead free gasoline production. references [1] pope, tim d., et al. "a study of catalyst formulations for isomerization of c7 hydrocarbons." applied catalysis a: general 233.1-2 (2002): 45-62. [2] pham-huu, cuong, et al. "n-hexane and n-heptane isomerization at atmospheric and medium pressure on moo3-carbon-modified supported on sic and γal2o3." applied catalysis a: general 132.1 (1995): 77-96. [3] sabyrov, kairat, et al. "hydroisomerization of nhexadecane: remarkable selectivity of mesoporous silica post-synthetically modified with aluminum." catalysis science & technology 7.8 (2017): 1756-1765. [4] exner, h., e. nagy, and f. fetting. "kinetics of the hydroisomerization of n-hexane on nickel containing zeolites." preprints-american chemical society. division of petroleum chemistry 36.4 (1991): 853863. [5] song, xuemei, et al. "the effect of palladium loading on the catalytic performance of pd/sapo-11 for ndecane hydroisomerization." molecular catalysis 433 (2017): 84-90. [6] vaudagna, s. r., r. a. comelli, and n. s. figoli. "influence of the tungsten oxide precursor on woxzro2 and pt/woxzro2 properties." applied catalysis a: general 164.1-2 (1997): 265-280. [7] al-hassany, maha. "effect of zro2, wo3 additives on catalytic performance of pt/hy zeolite compared with pt/γ-al2o3 for iraqi naphtha transformation." journal of engineering 15.4 (2009): 4378-4392. [8] al-saraj, mohammed abd atiya, ameel mohammed rahman, and maha h. al-hassani. "enhancement of iraqi light naphtha octane number using pt supported hmor zeolite catalyst." al-khwarizmi engineering journal 9.4 (2013): 1-11. [9] hussain, h. m., and a. a. k. mohammed. "preparation and characterization of mordenite zeolite from iraqi sand." iop conference series: materials science and engineering. vol. 518. no. 6. iop publishing, 2019. [10] ahmedzeki nada s., selahattin yilmaz, and ban a. al-tabbakh. "synthesis and characterization of nanocrystalline zeolite y." al-khwarizmi engineering journal 12, no. 1 (2016): 79-89. [11] güleç, hilal. liquid phase hydrogenation of citral on zeolite supported monometallic (ni, pt) and bimetallic (ni-sn, pt-sn) catalysts. ms thesis. izmir institute of technology, 2005. [12] szostak, r. "molecular sieves, principles of synthesis and identification. 1989." new york: thomson science (1989). [13] mohamed, mohamed m., ahmed kh nohman, and mohamed i. zaki. "development of catalytic properties of mordenite zeolite via chemical modification." catalysis 4 (2005). [14] aly, hisham m., moustafa e. moustafa, and ehab a. abdelrahman. "synthesis of mordenite zeolite in absence of organic template." advanced powder technology 23.6 (2012): 757-760. [15] smail, h., k. shareef, and z. ramli. "synthesis of mesoporous mordenite zeolite by different natural raw materials." aust j basic app sci 11 (2017): 27-34. [16] fahim, mohamed a., taher a. al-sahhaf, and amal elkilani. fundamentals of petroleum refining. elsevier, 2009. https://www.sciencedirect.com/science/article/abs/pii/s0926860x0200114x https://www.sciencedirect.com/science/article/abs/pii/s0926860x0200114x https://www.sciencedirect.com/science/article/abs/pii/s0926860x0200114x https://www.sciencedirect.com/science/article/abs/pii/0926860x95001514 https://www.sciencedirect.com/science/article/abs/pii/0926860x95001514 https://www.sciencedirect.com/science/article/abs/pii/0926860x95001514 https://www.sciencedirect.com/science/article/abs/pii/0926860x95001514 https://www.sciencedirect.com/science/article/abs/pii/0926860x95001514 https://pubs.rsc.org/en/content/articlelanding/2017/cy/c7cy00203c/unauth#!divabstract https://pubs.rsc.org/en/content/articlelanding/2017/cy/c7cy00203c/unauth#!divabstract https://pubs.rsc.org/en/content/articlelanding/2017/cy/c7cy00203c/unauth#!divabstract 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http://alkej.uobaghdad.edu.iq/index.php/alkej/article/view/180 http://alkej.uobaghdad.edu.iq/index.php/alkej/article/view/180 http://alkej.uobaghdad.edu.iq/index.php/alkej/article/view/180 http://alkej.uobaghdad.edu.iq/index.php/alkej/article/view/180 http://alkej.uobaghdad.edu.iq/index.php/alkej/article/view/180 https://iopscience.iop.org/article/10.1088/1757-899x/518/6/062002/meta https://iopscience.iop.org/article/10.1088/1757-899x/518/6/062002/meta https://iopscience.iop.org/article/10.1088/1757-899x/518/6/062002/meta https://iopscience.iop.org/article/10.1088/1757-899x/518/6/062002/meta https://iopscience.iop.org/article/10.1088/1757-899x/518/6/062002/meta http://alkej.uobaghdad.edu.iq/index.php/alkej/article/view/286 http://alkej.uobaghdad.edu.iq/index.php/alkej/article/view/286 http://alkej.uobaghdad.edu.iq/index.php/alkej/article/view/286 http://alkej.uobaghdad.edu.iq/index.php/alkej/article/view/286 https://openaccess.iyte.edu.tr/handle/11147/3209 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https://books.google.iq/books?hl=en&lr=&id=ucfsv1mmfhic&oi=fnd&pg=pp1&dq=%5b16%5d%09fahim,+mohamed+a.,+taher+a.+al-sahhaf,+and+amal+elkilani.+fundamentals+of+petroleum+refining.+elsevier,+2009.&ots=e1ath-yfrw&sig=osclqazmmrhbdwcfrxfbcissui4&redir_esc=y#v=onepage&q=%5b16%5d%09fahim%2c%20mohamed%20a.%2c%20taher%20a.%20al-sahhaf%2c%20and%20amal%20elkilani.%20fundamentals%20of%20petroleum%20refining.%20elsevier%2c%202009.&f=false https://books.google.iq/books?hl=en&lr=&id=ucfsv1mmfhic&oi=fnd&pg=pp1&dq=%5b16%5d%09fahim,+mohamed+a.,+taher+a.+al-sahhaf,+and+amal+elkilani.+fundamentals+of+petroleum+refining.+elsevier,+2009.&ots=e1ath-yfrw&sig=osclqazmmrhbdwcfrxfbcissui4&redir_esc=y#v=onepage&q=%5b16%5d%09fahim%2c%20mohamed%20a.%2c%20taher%20a.%20al-sahhaf%2c%20and%20amal%20elkilani.%20fundamentals%20of%20petroleum%20refining.%20elsevier%2c%202009.&f=false https://books.google.iq/books?hl=en&lr=&id=ucfsv1mmfhic&oi=fnd&pg=pp1&dq=%5b16%5d%09fahim,+mohamed+a.,+taher+a.+al-sahhaf,+and+amal+elkilani.+fundamentals+of+petroleum+refining.+elsevier,+2009.&ots=e1ath-yfrw&sig=osclqazmmrhbdwcfrxfbcissui4&redir_esc=y#v=onepage&q=%5b16%5d%09fahim%2c%20mohamed%20a.%2c%20taher%20a.%20al-sahhaf%2c%20and%20amal%20elkilani.%20fundamentals%20of%20petroleum%20refining.%20elsevier%2c%202009.&f=false h. m. hussain and a. a.k. mohammed / iraqi journal of chemical and petroleum engineering 20,4 (2019) 61 66 22 ni-pt / h-mordenite دراسة عممية أليزوميتة النفتا العراقية الخفيفة عمى محمد عبدالحميم عبدالكريم و حسين هالة محمد العراق-بغداد-كمية الفارابي الجامعة الخالصة عند درجة حرارة ni-pt / h-mordeniteتمت دراسة عممية االزمرة من النفثا العراقية عمى محفزالمحضر و في hr-1 1مع سرعة الفراغيه 3.3م ، نسبة الهيدروجين الى هيدروكاربون 0 322-222تتراوح بين الضغط الجوي. ثبوت السرعه ، في حين أن تكوين أظهرت النتائج ان تحول النفثا يزداد مع زيادة درجة حرارة التفاعل عند ن. ارتفاع عدد األوكتين النفثا م ، يتم تحويل التفاعل نحو تفاعل التكسير بالهيدروجي0 232أيزومرات أعمى عند .م0 232المتكون عند .بالتينيوم عمى موردنايت-ه, نيكلأزمرة النفثا العراقية الخفيف: الدالةالكممات available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.23 no.4 (december 2022) 71 – 80 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: ahmed radhi wattan, email: a.watten1308d@coeng.uobaghdad.edu.iq, name: mohammed salih aljwad, email: mjawad@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. normalize and de-normalize of relative permeability data for mishrif formation in wq1: an experimental work ahmed radhi wattan and mohammed salih aljwad petroleum engineering department – college of engineering – university of baghdad abstract in many oil-recovery systems, relative permeabilities (kr) are essential flow factors that affect fluid dispersion and output from petroleum resources. traditionally, taking rock samples from the reservoir and performing suitable laboratory studies is required to get these crucial reservoir properties. despite the fact that kr is a function of fluid saturation, it is now well established that pore shape and distribution, absolute permeability, wettability, interfacial tension (ift), and saturation history all influence kr values. these rock/fluid characteristics vary greatly from one reservoir region to the next, and it would be impossible to make kr measurements in all of them. the unsteady-state approach was used to calculate the relative permeability of five carbonate for core plugs from the mishrif formation of wq1. the relative permeability calculated by using johnson, bossler and naumann (jbn) correlation, which is, consider one of the unsteady-state approach where it found that the core plugs are water wet. a normalizing approach has been used to remove the effect of irreducible water and residual saturations, which would vary according on the environment. based on their own irreducible water and trapped saturations, the relative permeabilities can subsequently be denormalized and assigned to distinct sections (rock types) of the reservoir. the goal of this research is to normalize the relative permeability that was determined through water flooding. keywords: relative permeability, absolute permeability normalization, de-normalization. received on 06/07/2022, accepted on 31/08/2022, published on 30/12/2022 https://doi.org/10.31699/ijcpe.2022.4.9 1introduction in the laboratory, relative permeability (kr) is assessed using one of two methods: steady state or unsteady-state studies. the unsteady-state approach takes less time than the steady-state method, but it has a smaller range of saturation change. measuring kr in mixed-wet rocks with low-ift fluids is very difficult and necessitates specialized equipment [1]. a petroleum reservoir is a porous subsurface substance that traps oil, gas, or both structurally and stratigraphically. fluid movement in such a porous media is a very difficult phenomenon to understand. the physical parameters of reservoir fluids must be learned in order to understand and forecast the volumetric behavior of oil and gas reservoirs as a function of pressure. laboratory investigations on samples of actual reservoir fluids are frequently used to determine these fluid properties [2]. studying and analyzing a reservoir's performance necessitates a knowledge of the rock's physical properties as well as the existing interaction between the hydrocarbon system and the formation. laboratory investigations of cores from the reservoir to be examined are used to determine rock attributes. the cores are taken out of the reservoir, causing changes in the core bulk volume, pore volume, reservoir fluid saturations, and, in some cases, formation wettability [2]. one of the key sources of data available to aid the reservoir engineer in appraising the economic viability of a hydrocarbon accumulation is special core analysis (scal) [1]. special core analysis tries to extrapolate information from routine measurements to settings that are more indicative of reservoir conditions. in order to acquire a better knowledge of individual well and overall reservoir performance, scal data is used in conjunction with log and well test data. scal measurements, on the other hand, are more expensive and are often only performed on a small number of samples or when a challenging strategic reservoir management choice needs to be made (e.g. to gas flood, or not to gas flood). on intact core, tests are performed to determine fluid distribution, electrical properties, and fluid flow characteristics in two and occasionally three phase situations. fig. 1 shows a schematic diagram of common scal measurements [1]. in general, relative permeability is defined as the ratio of a continuous phase's conductance in a linked passage occupied by that phase to the overall conductance of the porous material. as a result, relative permeability of one phase denotes the contribution of that phase's flow to the overall flow. however, some elements of existing phases are not mobile in most displacement processes, and thus http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:a.watten1308d@coeng.uobaghdad.edu.iq mailto:mjawad@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2022.4.9 a. r. wattan and m. s. aljwad / iraqi journal of chemical and petroleum engineering 23,4 (2022) 71 80 72 do not contribute to flow until they join a continuousflowing channel [2]. as a result, there are two types of saturations in any phase distribution: mobile and immobile saturations, with only the mobile fluids contributing to flow and production. rock absolute permeability, wettability, ift, and hysteresis are significant characteristics that affect relative permeability because they control fluid dispersion inside porous media. the immobile fluids in the pore space of the rock limit the path available for mobile fluids to move [3]. fig. 1. schematic diagram of common scal measurements as a result, immobile-fluid saturation is an important factor to consider when determining relative permeability. the immobile saturation of any fluid is given as a function of other fluid saturations, rock absolute permeability, wettability, iff, and hysteresis behavior as shown in equation 1: simmobile=simmobile (s, k, wettability, ift, hysteresis) (1) to account for the influence of irreducible water and trapped saturations, which would vary depending on the conditions, normalization procedures have been proposed to described the classic normalization procedure as follows [4]: si normalize= (si-sir)/ (1-swr-sor-sgr) (2) i=oil, gas, water where sin represents the normalized saturation for phase i, si represents the phase saturation at any moment, and sir represents the residual (immobile) saturation for each phase obtained at the end of displacement. we presume that the kr under new conditions may be approximated from previous kr under different situations using the normalized saturation and the applicable irreducible and residual saturations. we use relative permeability (kr) normalization techniques on the experimental water-oil relative permeabilities in this paper. in the world of petroleum technology, core analysis is a relatively new development. the first studies on this topic were conducted in the context of analyzing and planning secondary oil recovery via water flooding. the current examination of flush field sands necessitates new and independent interpretations of cored material data. the development of quick, conventional methods for analyzing physical properties of sandstone, such as permeability, porosity, and grain size, and the fluid content of the sand, is a priority [5]. scal data, particularly capillary pressure (pc) and relative permeability (kr), are critical inputs to the reservoir simulation model, whose predictions are used to orient exploration and production decisions toward optimum productivity and maximum oil recovery [6]. in heterogeneous, fractured, and/or anisotropic rocks, whole core analysis is required to characterize porosity and directional permeability. for heterogeneous reservoirs, full core measurements are necessary because small-scale variability may not be effectively reflected by plug measurements. in heterogeneous rocks, whole core analysis (special core analysis) is also required for determining multi-phase flow parameters [1]. the findings of relative permeability testing on a large number of reservoir rock core samples are typically inconclusive. as a result, relative permeability data collected from different rock samples must be averaged. the relative permeability curves should be standardized before being utilized for oil recovery prediction to eliminate the effect of variable initial water and critical oil saturations. based on the required fluid saturation for each reservoir site, the relative permeability can then be a. r. wattan and m. s. aljwad / iraqi journal of chemical and petroleum engineering 23,4 (2022) 71 80 73 de-normalized and assigned to different regions of the reservoir [7]. according to l.p. dake (1979) [8], effective permeability plots can be adjusted by dividing the scales by the absolute permeability k value to obtain relative permeability plots. kro(sw)=ko(sw)/k (3) krw(sw)=(kw(sw))/k (4) the experimental calculations of relative permeability data and compare it with another correlation makes this work very important to reduce the cost of doing many experiments in the lab. the important of relative permeability data in the simulation models makes the normalizing and denormalizing methods very important where it can be used normalizing process to reduce the number of curves for relative permeability data that used in the models and to know the wettability of the field from the intersection between oil and water relative permeabilities. the goal of this research is to normalize the relative permeability that was determined through water flooding. 2permeability permeability is assessed by flowing a viscous fluid through a core plug with defined dimensions (a and l) and measuring the flow rate q and ∆p, as shown in equation 5 [9]: 𝐾 = 𝑞𝜇𝐿 𝐴∆𝑝 (5) where: k = proportionality constant, or permeability, (darcy’s), 𝜇 = viscosity (cp), q = flow rate through the porous medium, (𝑐𝑚3/sec), l = length of core, (𝑐𝑚), a = cross-sectional area, (𝑐𝑚2). when measuring permeability, the following conditions must be met:  laminar (viscous) flow.  there is no response between the fluid and the rock.  at 100% pore space saturation, only a single phase is present. permeability can be classified into: 2.1. absolute permeability the permeability measurement is sometimes referred to as specific or absolute permeability when the medium is totally saturated with one fluid. the steady-state flow equation 5 is frequently used to compute absolute permeability [9]. 2.2. effective permeability the effective permeability is the permeability to a specific fluid when there are multiple fluids present in the rock pore spaces [9]. when a porous media is saturated with more than one fluid, effective permeability is a measure of the fluid conductance capacity to that particular fluid. oil 𝐾𝑒𝑜 = 𝑞𝑜𝜇𝑜𝐿 𝐴 ∆𝑝𝑜 (6) water 𝐾𝑒𝑤 = 𝑞𝑤𝜇𝑤𝐿 𝐴 ∆𝑝𝑤 (7) gas 𝐾𝑒𝑔 = 𝑞𝑔𝜇𝑔𝐿 𝐴 ∆𝑝𝑔 (8) 2.3. relative permeability when two or more immiscible fluids are present in a formation, each fluid tends to obstruct the flow of the others. the relative permeability impact is the reduction in a fluid's ability to flow through a permeable medium. in other terms, it is the ratio of a phase's effective permeability. for the oil phase the effective permeability ko and oil relative permeability kro given by equation 9 [9]: 𝐾𝑟𝑜 = 𝐾𝑜 𝐾 (9) 𝐾𝑟𝑤 = 𝐾𝑤 𝐾 (10) 𝐾𝑟𝑔 = 𝐾𝑔 𝐾 (11) where: k=the absolute permeability, 𝑘𝑟𝑜, 𝑘𝑟𝑤, 𝑘𝑟𝑔 is the relative permeability for oil, water, gas respectively, 𝑘𝑜, kw, kg is the effective permeability for oil, water, gas respectively. effective and a number of factors influences relative permeability:  saturations of fluids.  rock pore space geometry and grain size distribution.  wettability of rocks as shown in fig. 2.  history of fluid saturation (i.e., imbibition or drainage). -effect of wettability on relative permeability the importance of relative permeability curves in reservoir evaluations stems from their capacity to predict fluid output during reservoir investigation. they found a connection between phase saturation and the rock's capacity to produce for a particular phase. these curves are determined through a sequence of standard measurements and calculations carried out in specialized core laboratories, typically utilizing specific forms of frontal advance theory. the single most crucial stage in generating an accurate history match and properly projecting future performance is the production of realistic relative permeability curves. the engineer is frequently forced to seek analog data from offset rocks in the absence of relative permeability data, which will hopefully represent the fluid flow characteristics inside the reservoir of interest [9]. a. r. wattan and m. s. aljwad / iraqi journal of chemical and petroleum engineering 23,4 (2022) 71 80 74 fig. 2. effect of wettability on relative permeability 3permeability from the core for a fluid of known viscosity, all laboratory methods for estimating permeability rely on the measurement or interpretation of a flow rate through and a pressure drop across a sample of known length and cross sectional area. darcy law is then used to examine the data. in principle, the type of the fluid should not matter; but, when the rock and fluid interact, the nature of the fluid is critical. the permeability measuring method can be classified depending on the sample type (plug or complete demeter core), the fluid employed (gas or liquid), and the procedure used (steady or unsteady state conditions). standard laboratory analysis processes will generally offer reliable data on permeability of core samples, but the sample type affects the amount and quality of information that may be obtained. if the rock is not homogeneous, whole core analysis, will most likely produce more accurate results than core plug analysis (small pieces cut from the core) [10]. cutting the core with an oil-base mud is one procedure that has been utilized to improve the accuracy of the permeability determination. using a pressure-core barrel and reservoir oil to conduct the permeability tests. overburden pressure affects permeability because it is an evaluation of the permeability of the reservoir rock in the system, which is an isotropic property of porous rock in some defined sections of the system, meaning it is directional. this factor should be taken into account in deep wells. plug samples drilled parallel to bedding planes called horizontal permeability (kh) and perpendicular to the bedding plane called vertical permeability (kv) [10]. when calculating reservoir permeability, various factors must be addressed as possible sources of inaccuracy. these are the factors:  because of reservoir variability, a core sample may not be typical of the reservoir rock.  it's possible that core recuperation isn't complete.  when the core is cut or dried in preparation for analysis, the permeability of the core may be altered. when the rock contains reactive clays, this problem is more likely to arise.  the sampling procedure could be skewed. there is a strong tendency to analyze only the best portions of the core. 4experimental materials and setup 4.1. materials all investigations used reservoir crude oil from the mishrif formation in the wq1 field. to eliminate any possible solid particles, the oil was filtered using a 5.0-lm filter paper (using a vacuum pump). at room temperature of 25 oc, the oil density and viscosity are 0.9 g/cc and 10 cp, respectively. the high viscosity of crude oil making the experiments are difficult. the dead oil diluted by gas oil with percentage 80 % to decrease the viscosity where the viscosity and density of the new oil prepared are 4.5 cp and 0.82 g/cc. formation water taken from the field that used to saturate core plugs and to make water-flooding experiments. the salinity of formation water is 180 kppm. the composition of formation water as shown in table 1. for the experiments, five core samples were used. xrd (x-ray diffraction) examination revealed that samples were primarily composed of calcite, which accounted for more than 97 percent of the rock's mineralogy. the permeability of the cores ranged from (6.02-143 md), with porosities ranging from 15 to 25%. table 2 shows the petrophysical parameters of the core. each core is 1.5 inch (3.81 cm) in diameter and varies in length between (7.09-7.3 cm). table 1. the analysis composition of formation water example column(a) water injected formation water component ppm cl 96205 so4 650 na 50089 ca 12390 mg 3736 a. r. wattan and m. s. aljwad / iraqi journal of chemical and petroleum engineering 23,4 (2022) 71 80 75 table 2. core dimensions and petrophysical properties sample length(cm) pore volume,cm3 porosity,% permeability ,md 1 7.3 12.91 16.06 7.597 2 7.25 13.28 16.62 143.7 3 7.3 17.71 22.01 8.583 4 7.09 18.22 23.39 6.02 5 7.25 17.83 22.42 6.375 xrd was test before injection for limestone core sample as shown in fig. 3 for the plug 4. from xrd test we notice that the mineral composition for limestone plug 4 is caco3 (calcite) with percentage 97% and sio2 (quartz) with percentage 3%. fig. 3. xrd for the plug 4 4.2. core saturation procedure the following procedure applied to saturate the core plugs and calculate the absolute permeability: 1. cleaning the core plugs by using toluene or methanol in the soxhlet extraction device [11]. 2. after placing the cores in the desiccator, a vacuum was applied for one hour to eliminate any remaining air. 3. in the desiccator, drops of formation brine were administered until the formation brine filled the cores inside the beaker. 4. set the vacuum pump to remove all potential air from the core for 6 to 8 hours. 5. the cores were vacuum-sealed and kept in the desiccator for two days. 6. the pore volume was calculated using the weight difference (wet weight -dry weight) and brine density. at this point, the porosity may be computed. the computed pore volume and porosity are presented in table 2. 5the methodology  relative permeability calculations following the completion of the flooding sequence and operations, the following approach was used to collect all of the necessary data for relative permeability estimates [12].  johnson, bossler and naumann (jbn) correlation a three-step process may be summarized as follows: equation 12 provides the injection of pore volume 𝑃𝑉𝑖𝑛𝑗 = 𝑊𝑖 𝑃𝑉 (12) where: 𝑃𝑉𝑖𝑛𝑗 = pore volume injection, wi = water injected in total, cc. equation 13 of the welge technique calculates average water saturation at the outlet face of rock samples. 𝑆𝑊𝑎𝑣𝑔 = 𝑆𝑊𝑖 + 𝑁𝑃 𝑃𝑉 (13) where: np = oil production through time, swi= initial saturation with water, fraction, sw avg= the average water saturation of the rock samples' outflow face, fraction. welge demonstrated that displacing phase saturation downstream at the core's end (sw2) is related to average displacing phase saturation (swavg), fractional flow of the displaced phase (oil), and injected pore volume as in equation 14. 𝑆𝑤2 = 𝑆𝑊𝑎𝑣𝑔 − (𝑓𝑜 ∗ 𝑊𝑖) (14) where: sw₂ = end-of-core saturation, fraction, fo = the displaced phase's fractional flow (oil), fraction. for any given injection, the fractional flow of oil may be determined by determining the average and intercept saturations: 𝑓𝑜 = ∆𝑆𝑤 ∆𝑃𝑣𝑖𝑛𝑗 (15) also, 𝑓𝑤 = 1 − 𝑓𝑜 (16) where: fw= the displacing phase's fractional flow of water, fraction. darcy's law was used to calculate the average oil viscosity for each pressure drop: 𝜇𝑜 = 𝐾𝑜∗𝐴∗δ𝑃𝑖𝑛𝑗 𝑞∗𝐿∗14700 (17) where: μ₀= obtained average oil viscosity, cp, ko = permeability of oil, md, q = flow rate, cc/sec. the average oil viscosity and the injected pore volume affect the effective viscosity: 𝜆 = 𝜇𝑎𝑣𝑔 − ( δ𝜇𝑎𝑣𝑔 δ𝑃𝑣𝑖𝑛𝑗 ) ∗ 𝑃𝑣𝑖𝑛𝑗) (18) where: λ = effective viscosity, cp. finally, the following equations are used to calculate the relative permeabilities: 𝐾𝑟𝑜 = 𝜇𝑜 ∗ 𝑓𝑜 𝜆 (19) 𝐾𝑟𝑤 = 𝜇𝑜∗𝑓𝑤 𝜆 (20) 6results and discussion because absolute permeability is a significant aspect in the calculations of relative permeability, the absolute a. r. wattan and m. s. aljwad / iraqi journal of chemical and petroleum engineering 23,4 (2022) 71 80 76 permeability for the five core plugs discovered after the saturation process with varying flow rates for larger pore volumes. 6.1. absolute permeability calculations after the core plugs saturated with formation water by vacuum pump, the liquid permeability for the core plugs are calculated by injection the brine [13]. pore volume for core plug 1 is 12.91 cm3 as shown in table 2. therefore, we injected more than 1.5 pore volumes from the brine with injection rate 2 cm3/min to calculate the absolute permeability where the pressure stabilizes at 50 psi as shown in fig. 4 after applying darcy law the absolute permeability found 7.14 md. the absolute permeability for plug 2, calculated by injection various rates and record pressure drop as shown in fig. 5. by applying darcy law and taking the average value for the absolute permeability, we calculate it 143.7 md. the same procedure for the other plugs where more than one pore volume injected to calculate the absolute permeability before relative permeability water flooding experiments. the absolute permeability for the plug 3, 4 and 5 as seen in table 3 and fig. 6 and fig. 7. fig. 4. absolute permeability for plug 1 fig. 5. time versus pressure to calculate absolute permeability for plug 2 6.2. oil injection experiment the oil injected with flowing rate 0.5 cm3/min for all core-flooding experiments to calculate the oil relative permeability and residual water saturation where the results seen in table 3. the high value of residual water saturation for plug 2, which is 44% and low value for the plugs 1 and 3, which is 20%. fig. 6. time versus pressure to calculate absolute permeability for plug 3 fig. 7. time versus pressure to calculate absolute permeability for plug 4 6.3. coreflood experiments after the cores flooded with oil, the final pressure of oil injected recorded and stopped the injection process [14]. to measure the oil and water relative permeabilities, the formation water injected with rate 0.5 cm3/min after the system pressure raised to the last pressure value from the oil experiment. for plug 1, the oil and water relative permabilities as shown in fig. 8. where the intersection between kro and krw is more than 50%, which mean this plug is water wet. the same procedure for the other plugs as shown in fig. 9 to fig. 12 for the plugs 2, 3, 4, and 5. table 3 summarize the relative permeability calculations. table 3. summarize of special core analysis data parameters plug 1 plug 2 plug 3 plug 4 plug 5 swi,% 20 44 20 28.1 27.12 ioic,cc 10 7.92 13 13.11 13.64 kl,md 7.514 143.7 8.45 6 6.23 ko,md 4.35 36.27 4.56 2.98 5.39 kw,md 2.46 34.92 4.16 1.87 3.19 krw 0.327 0.642 0.492 0.311 0.512 kro 0.579 0.667 0.540 0.497 0.865 sor,% 18 24 19.95 37.37 13.87 np,cc 8.311 6 10.65 8.1 11.775 rf,% 83.11 75.76 81.92 61.78 88.71 rf at bt,% 40 37.87 58.46 38.14 66 wettability waterwet waterwet waterwet waterwet waterwet a. r. wattan and m. s. aljwad / iraqi journal of chemical and petroleum engineering 23,4 (2022) 71 80 77 fig. 8. relative permeability curve for plug 1 fig. 9. relative permeability curve for plug 2 fig. 10. relative permeability curve for plug 3 fig. 11. relative permeability curve for plug 4 6.4. normalization and averaging relative permeability data the procedure for normalize relative permeability data. step 1. calculate the normalized water saturation sw* for each core sample by using equation: 𝑆𝑤 ∗= 𝑆𝑤−𝑆𝑤𝑐 1−𝑆𝑤𝑐−𝑆𝑜𝑐 (21) step 2. determine the relative permeability of oil [(kro)swc] and relative permeability to water [(krw)sor] from the experiments as shown in table 4 fig. 12. relative permeability curve for plug 5 table 4. the relative permeability values at critical saturation [12] plug no plug 1 plug 2 plug 3 plug 4 plug 5 kro(swc) 0.831 0.254 0.926 0.497 0.647 krw(sor) 0.327 0.217 0.564 0.324 0.319 step 3. calculate the normalized kro* and krw* for all core samples as shown in table 4 from the following equations: 𝐾𝑟𝑜 ∗= 𝐾𝑟𝑜 (𝐾𝑟𝑜)𝑆𝑤𝑐 (22) 𝐾𝑟𝑤 ∗= 𝐾𝑟𝑤 (𝐾𝑟𝑤)𝑆𝑜𝑐 (23) where: kro =relative permeability of oil at different sw, kro(swc)= relative permeability of oil at connate water saturation, kro* = normalized relative permeability of oil, (krw)soc is the relative permeability of water at the critical oil saturation. the normalized water saturation and relative permeability shown in table 5. table 5. normalized water saturation and relative permeability [12] plug no 5 plug no 6 sw* kro* krw* sw* kro* krw* 0 1 0 0 1 0 0.433321 0.54837 0.291199 0.392409 0.222224 0.288452 0.643981 0.264407 0.42 0.59791 0.458341 0.458341 0.831976 0.0937 0.699048 0.658771 0.535723 0.535723 0.930373 0.04815 0.634664 0.826436 0.021732 0.737022 0.94 0.036113 0.7 0.928106 0.000233 0.920774 0.96 0.001204 0.909685 1 0 1 0.98 0.00000012 0.999308 1 0 1 step 4: calculate the average normalized relative permeability for the oil and water from the following equations: (𝐾𝑟𝑤 ∗)𝑎𝑣𝑔 = ∑ (ℎ𝑘 𝐾𝑟𝑤∗)𝑖𝑛𝑖=1 ∑ (ℎ𝑘)𝑖𝑛𝑖=1 (24) (𝐾𝑟𝑜 ∗)𝑎𝑣𝑔 = ∑ (ℎ𝑘 𝐾𝑟𝑜∗)𝑖𝑛𝑖=1 ∑ (ℎ𝑘)𝑖𝑛𝑖=1 (25) a. r. wattan and m. s. aljwad / iraqi journal of chemical and petroleum engineering 23,4 (2022) 71 80 78 where: n=total number of core samples, hi= thickness of sample i, ki=absolute permeability of sample i. step 5. plot the normalized values of kro* and krw* versus sw* for each core on a regular graph paper as shown in fig. 13. fig. 13. the normalized values of kro* and krw* vs sw* step 6. select arbitrary values of sw* and calculate the average kro* and krw* by applying equations 24 and 25 as shown in table 6 and fig. 14. table 6. the average relative permeability versus sw* sw* kroavg krwavg 0 1 0 0.2 0.603367 0.134923 0.4 0.4215 0.314 0.6 0.312 0.4125 0.8 0.156 0.699048 1 0 1 fig. 14. average relative permeability versus average sw 6.5. de-normalizing the relative permeability data taking the average connate water saturation and residual oil saturation for the five core plugs where (swc)avg=0.226 and (sor)avg=0.278, de-normalize the data to generate the required relative permeability data as shown in table 7 and fig. 15. table 7. average relative permeability and water saturation sw kro krw 0.2782 0.630796 0 0.377294 0.380602 0.047298 0.476388 0.265881 0.110075 0.575481 0.196808 0.144605 0.674575 0.098404 0.245057 0.773669 0 0.350558 fig. 15. average relative permeability versus average sw after normalize all relative permeability data we noticed that the intersection between oil and water relative permeabilities at water saturation 0.6 which means that the mishrif formation in west qurna-1 is water wet. 7conclusions  we apply normalize technique to remove the effect of variable irreducible water saturation in the relative permeability calculations.  the absolute permeability is important factor in the calculations of relative permeability, therefore it must be known for different flow rates and record different pressure drop.  after applying de-normalize technique for carbonate core plugs of mishrif formation, we found that mishrif formation is water-wet where the intersection of relative permeability for the oil and water versus water saturation more than 50%.  the relative permeability curves should be adjusted before being used for oil recovery prediction to eliminate the effect of variable initial water and critical oil saturations. based on the essential fluid saturation for each reservoir location, the relative permeability can then be de-normalized and given to distinct regions of the reservoir. from relative permeability data, we noticed that the higher values of oil and water relative permabilities are 0.865 and 0.642 respectively. acknowledgment the authors are grateful to basra oil company, ministry of oil for providing core samples, oil and brine solutions. grateful to the petroleum department use the lab and facilities. a. r. wattan and m. s. aljwad / iraqi journal of chemical and petroleum engineering 23,4 (2022) 71 80 79 references [1] honarpour, m. m., djabbarah, n. f. & sampath, k. whole core analysis-experience and challenges. middle east oil show, 2003. society of petroleum engineers. [2] richard o. baker et al. “practical reservoir engineering and characterization” department of chemical and petroleum engineering, university of calgary, canada, 2015. [3] amir jahanbakhsh et al “relative permeability normalization effects of permeability, wettability and interfacial tension “spe-170796-ms, 2014. [4] mawla, r. a., & al-saadoon, f. t. (1978, january 1). normalization techniques and interpretive practices of relative permeability curves of reservoir rocks. society of petrophysicists and well-log analysts. [5] pyle, h. c, and sherborne, j. e.: trans. aime (1939), impact of research on oil recovery 132, 33. [6] meissner, j. p., wang, f. h. l., kraiik, j. g., majid, a., naguib, m., omar, m. 1., & & al-ansari ,k. a. (2009, january). state of the art special core analysis program design and results for effective reservoir management, dukhan field, qatar. in international petroleum technology conference . international petroleum technology conference. [7] ahmed, t. 2010. reservoir engineering handbook gulf professional publishing. houston. [8] dake, l. p. 1983. fundamentals of reservoir engineering, elsevier. [9] hussain ali baker et al,” permeability prediction in carbonate reservoir rock using fzi” iraqi journal of chemical and petroleum engineering, vol.14 no.3 (september 2013). [10] danesh, a., todd, a. c., somerville, j. et al. 1990. direct measurement of interfacial tension, density, volume, and compositions of gas condensate system. chem. eng. res. des. 68. [11] tariq m. naifea et al “treatment of used lubricant oil by solvent extraction” iraqi journal of chemical and petroleum engineering, vol.23 no.1 (march 2022). [12] wattan, a.r. “investigation of smart water flooding in mishrif and zubair reservoirs in west-qurna-1 oil field”, phd dissertation, baghdad university, 2022. [13] jalal abdulwahid et al “estimation liquid permeability using air permeability”, iraqi journal of chemical and petroleum engineering, vol.15 no.1 (march 2014). [14] ahmed noori, et al “using different surfactants to increase oil recovery of rumaila field (experimental work)” iraqi journal of chemical and petroleum engineering, vol.17 no.3 (september 2016). https://onepetro.org/ree/article-abstract/8/06/460/112497/whole-core-analysis-experience-and-challenges?redirectedfrom=fulltext https://onepetro.org/ree/article-abstract/8/06/460/112497/whole-core-analysis-experience-and-challenges?redirectedfrom=fulltext https://onepetro.org/ree/article-abstract/8/06/460/112497/whole-core-analysis-experience-and-challenges?redirectedfrom=fulltext https://onepetro.org/ree/article-abstract/8/06/460/112497/whole-core-analysis-experience-and-challenges?redirectedfrom=fulltext https://books.google.iq/books?hl=en&lr=&id=fpgcbaaaqbaj&oi=fnd&pg=pp1&dq=%5b2%5d%09richard+o.+baker+et+al.+%e2%80%9cpractical+reservoir+engineering+and+characterization%e2%80%9d+department+of+chemical+and+petroleum+engineering,+university+of+calgary,+canada,+2015.&ots=5w-wb4y7ug&sig=knxh6gpgi_ibt5_inlttsqcoop0&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=fpgcbaaaqbaj&oi=fnd&pg=pp1&dq=%5b2%5d%09richard+o.+baker+et+al.+%e2%80%9cpractical+reservoir+engineering+and+characterization%e2%80%9d+department+of+chemical+and+petroleum+engineering,+university+of+calgary,+canada,+2015.&ots=5w-wb4y7ug&sig=knxh6gpgi_ibt5_inlttsqcoop0&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=fpgcbaaaqbaj&oi=fnd&pg=pp1&dq=%5b2%5d%09richard+o.+baker+et+al.+%e2%80%9cpractical+reservoir+engineering+and+characterization%e2%80%9d+department+of+chemical+and+petroleum+engineering,+university+of+calgary,+canada,+2015.&ots=5w-wb4y7ug&sig=knxh6gpgi_ibt5_inlttsqcoop0&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=fpgcbaaaqbaj&oi=fnd&pg=pp1&dq=%5b2%5d%09richard+o.+baker+et+al.+%e2%80%9cpractical+reservoir+engineering+and+characterization%e2%80%9d+department+of+chemical+and+petroleum+engineering,+university+of+calgary,+canada,+2015.&ots=5w-wb4y7ug&sig=knxh6gpgi_ibt5_inlttsqcoop0&redir_esc=y#v=onepage&q&f=false https://onepetro.org/speatce/proceedings-abstract/14atce/all-14atce/spe-170796-ms/211867 https://onepetro.org/speatce/proceedings-abstract/14atce/all-14atce/spe-170796-ms/211867 https://onepetro.org/speatce/proceedings-abstract/14atce/all-14atce/spe-170796-ms/211867 https://onepetro.org/spwlaals/proceedings-abstract/spwla-1978/all-spwla-1978/spwla-1978-j/19867 https://onepetro.org/spwlaals/proceedings-abstract/spwla-1978/all-spwla-1978/spwla-1978-j/19867 https://onepetro.org/spwlaals/proceedings-abstract/spwla-1978/all-spwla-1978/spwla-1978-j/19867 https://onepetro.org/spwlaals/proceedings-abstract/spwla-1978/all-spwla-1978/spwla-1978-j/19867 https://onepetro.org/spwlaals/proceedings-abstract/spwla-1978/all-spwla-1978/spwla-1978-j/19867 https://onepetro.org/iptconf/proceedings-abstract/09iptc/all-09iptc/iptc-13664-ms/152372 https://onepetro.org/iptconf/proceedings-abstract/09iptc/all-09iptc/iptc-13664-ms/152372 https://onepetro.org/iptconf/proceedings-abstract/09iptc/all-09iptc/iptc-13664-ms/152372 https://onepetro.org/iptconf/proceedings-abstract/09iptc/all-09iptc/iptc-13664-ms/152372 https://onepetro.org/iptconf/proceedings-abstract/09iptc/all-09iptc/iptc-13664-ms/152372 https://onepetro.org/iptconf/proceedings-abstract/09iptc/all-09iptc/iptc-13664-ms/152372 https://onepetro.org/iptconf/proceedings-abstract/09iptc/all-09iptc/iptc-13664-ms/152372 https://books.google.iq/books?hl=en&lr=&id=mfqpqma62w8c&oi=fnd&pg=pp1&dq=%5b8%5d%09dake,+l.+p.+1983.+fundamentals+of+reservoir+engineering,+elsevier.&ots=fr1dopszgf&sig=vxwgrqkg8z8803mtctsnxl5fwyu&redir_esc=y#v=onepage&q=%5b8%5d%09dake%2c%20l.%20p.%201983.%20fundamentals%20of%20reservoir%20engineering%2c%20elsevier.&f=false https://books.google.iq/books?hl=en&lr=&id=mfqpqma62w8c&oi=fnd&pg=pp1&dq=%5b8%5d%09dake,+l.+p.+1983.+fundamentals+of+reservoir+engineering,+elsevier.&ots=fr1dopszgf&sig=vxwgrqkg8z8803mtctsnxl5fwyu&redir_esc=y#v=onepage&q=%5b8%5d%09dake%2c%20l.%20p.%201983.%20fundamentals%20of%20reservoir%20engineering%2c%20elsevier.&f=false https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/318 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/318 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/318 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/318 https://researchportal.hw.ac.uk/en/publications/direct-measurement-of-interfacial-tension-density-volume-and-comp https://researchportal.hw.ac.uk/en/publications/direct-measurement-of-interfacial-tension-density-volume-and-comp https://researchportal.hw.ac.uk/en/publications/direct-measurement-of-interfacial-tension-density-volume-and-comp https://researchportal.hw.ac.uk/en/publications/direct-measurement-of-interfacial-tension-density-volume-and-comp https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/864 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/864 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/864 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/864 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/267 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/267 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/267 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/267 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/210 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/210 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/210 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/210 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/210 a. r. wattan and m. s. aljwad / iraqi journal of chemical and petroleum engineering 23,4 (2022) 71 80 80 ةنالمشرف في حقل غرب القر ةلتكوين طبق ةالنسبي ةلبيانات النفاذي ةتعديل وتسوي :عمل تجريبي1 محمد صالح الجوادو احمد راضي وطن قسم هندسة النفط/ كلية الهندسة/ جامعة بغداد الخالصة تشار التي تؤثر على ان مهم في الجريان هي عامل ةالنسبي ة, النفاذيفي الكثير من انظمه استخالص النفط لحصول ل ةمن المكمن واجراء دراسات مختبري ةتم اخذ نماذج صخري تقليديا .ةالنفطيالمائع وتنتج من المصادر كل فانه توزيع ش المائعلتشبع ةهي دال ةالنسبي ةان النفاذي ةبالرغم من حقيق .ةعلى خواص المكمن المهم ههذ .ةلنسبيا ةفاذي, الشد البيني, وتاريخ التشبع جميعها تؤثر على قيم النة, التبلليةالمطلق ةمسامات, النفاذيال الى اخرى وهذا يجعل من غير الممكن قياس جميع قيم ةبصورة كبيرة من منطق خصائص الصخرة/المائع تتغير ماذج ن ةلخمس ةالنسبي ةالمستقرة استخدمت لحساب النفاذي غير ةالحال ةطريق .المناطق هلهذ ةالنسبي ةنفاذيال ةمعادل ةبواسط ةالمحسوب ةالنسبي ةالنفاذي .1-ةالمشرف لحقل غرب القرن ةكاربونيت من طبق ةصخري johnson, bossler and naumann (jbn) المستقرة وجدت ان غير ةاحد طرق النفاذي التي تعتبر ت لتشبعاوا ةاثير تشبع الماء غير قابل لالزاحت ةمبدا تعديل استخدم الزال بالماء. ةهي مبلل ةالنماذج الصخري يتم ةنسبيال ةفان النفاذي ةعلى تشبع الماء غير قابل لألزاح اعتمادا .التي تتغير من صخرة الى اخرى ةالمتبقي ةسبيالن ةاذيفالهدف من هذا البحث تعديل الن .)نوع الصخرة( من المكمن ةتسويتها وتعيينها للمقاطع الواضح .التي تم ايجادها خالل تجارب حقن الماء .ةالتسوي , التعديل,ةالمطلق ةالنفاذي, ةالنسبي ةالكلمات الدالة: النفاذي available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol. 24 no.2 (june 2023) 65 – 70 eissn: 2618-0707, pissn: 1997-4884 *corresponding author: name: darya khalid faidhllah, email: daryakhalid2@gmail.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. prediction of hydraulic flow units for jeribe reservoir in jambour oil field applying flow zone indicator method darya khalid faidhllah a, * and sameera m. hamd-allah a a petroleum engineering department, college of engineering, university of baghdad, iraq abstract the jeribe reservoir in the jambour oil field is a complex and heterogeneous carbonate reservoir characterized by a wide range of permeability variations. due to limited availability of core plugs in most wells, it becomes crucial to establish correlations between cored wells and apply them to uncored wells for predicting permeability. in recent years, the flow zone indicator (fzi) approach has gained significant applicability for predicting hydraulic flow units (hfus) and identifying rock types within the reservoir units. this paper aims to develop a permeability model based on the principles of the flow zone indicator. analysis of core permeability versus core porosity plot and reservoir quality index (rqi) normalized porosity log-log plot reveals the presence of three distinct hydraulic flow units and corresponding rock types within the jeribe reservoir. these rock types can be identified if known. the reservoir can be divided into three groups of rock types, namely good, moderate, and bad quality. the bad rock type represents a restricted section within the reservoir, while the upper and lower parts predominantly consist of moderate-quality rock types. conversely, the central section of the reservoir exhibits a good-quality rock type. by utilizing the flow zone indicator principles, this study provides valuable insights into the hydraulic flow behavior and rock types present in the jeribe reservoir. the proposed permeability model derived from this method can aid in predicting permeability values for uncored wells, contributing to a better understanding of the reservoir's heterogeneity and facilitating reservoir characterization and management decisions. keywords: jeribe reservoir, flow zone indicator, jambour oil field, hydraulic flow units, permeability prediction. received on 03/10/2022, received in revised form on 27/12/2022, accepted on 03/01/2023, published on 30/06/2023 https://doi.org/10.31699/ijcpe.2023.2.7 1introduction when there is a lack of data, one of the most important problems in reservoir analysis is forecasting reservoir permeability [1]. to identify the formation evaluation and reservoir quality processes that are used in reservoir discovery, production, and improvement for the reservoir to evaluate if a potential oil field is economically feasible, the estimation of petrophysical properties such as permeability is quite important [2]. identifying carbonate reservoirs is difficult due to their heterogeneity and propensity for tightness brought on by depositional and digenetic processes [3]. jambour oil field is located northeast of kirkuk governorate, and its production began in august 1959 [4]. the jeribe formation represents a heterogeneous formation originally described as organic detrital limestone. the formation was defined by bellen in 1957 [5]. the permeability of a zone can be found in the well logs. by experimentally correlating the log response to core permeability data and the porosity, certain well logs and their outputs, such as porosity logs, can be applied to predict permeability [6]. because permeability is a measure of the parameters of the formation, determining it from a well log is particularly difficult [7]. this is because the relationship between porosity and permeability may not be very accurate [8]. the hydraulic flow unit idea was put used by amaefule et al. (1993) as a guiding principle for separating reservoirs into various rock types showing various porethroat characteristics. to distinguish the rock types that form the basis of this reservoir characterization tool, the fzi (flow zone indicator) serves as the main parameter in this approach [9]. in 2017, a study of the jeribe reservoir in the mansuriyah gas field estimated permeability to use both traditional and flow zone indicator methods to determine permeability using (451 samples) gathered from four wells. the research concluded that the classical method's correlation coefficient for the linear regression relationship between core permeability and porosity was (0.4363). as a result, the fzi approach was used to divide the reservoir into four zones with better correlation coefficients of more than 0.75 [10]. this study's goals are to determine the hydraulic flow units for the jeribe reservoir in the jambour oil field, contrast the permeability of the reservoir's core to that anticipated by the fzi permeability, and divide the reservoir vertically following the fzi results. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:daryakhalid2@gmail.com http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2023.2.7 d. k. faidhllah and s. m. hamd-allah / iraqi journal of chemical and petroleum engineering 24,2 (2023) 65 70 66 2hydraulic flow units (hfu) estimation the traditional method of classifying rock types is dependent on an individual's subjective understanding of geology and an analytical correlation between permeability and porosity [11]. this traditional approach should be troublesome when considering such numerous flow units because the permeability of various locations within a particular rock may not limit to any certain porosity [12]. to solve this issue, the kozeny-carmen equation uses the reservoir quality index (rqi) and flow zone indicator (fzi) to characterize the hydraulic units inside mappable geological units (facies). rqi is used to calculate rock quality for heterogeneous reservoir conditions based on the non-linear relationship between permeability and porosity [13]. it also can be used to define the hydraulic unit's fzi. according to mineralogy and their geological texture, fzi is essentially a singular parameter that assists in the identification of distinctive pore geometrical facies [9]. based on geological and physical factors at the pore size, the hydraulic flow unit (hfu) approach has been created to recognize and categorize different rock types. it can primarily be utilized to enhance the connections between well-to-well rock characteristics and permeability forecasting [14]. the geological and petrophysical reservoir rock parameters influence the hydraulic flow units. the petrophysical qualities include porosity and permeability, which are influenced by depositional facies and diagenetic processes, while the geological properties include rock texture and mineralogy, as well as sedimentary formations. a few hfu can exist within a single facies zone [15]. the correlation between the reservoir quality index (rqi), which describes the geometric distribution of pore space, and the normalized porosity (z), is represented by the individual fzi for each reservoir flow unit. 𝑅𝑄𝐼 = 0.0314√ 𝐾 ∅𝑒 (1) where: rqi is the reservoir quality index measured in (µm), øe is the effective porosity of the core in fraction, and k is the absolute permeability of the core in md. ∅𝑍 = ∅𝑒 1−∅𝑒 (2) where øz is the normalized porosity or the ratio of pore volume to grain volume. finally, fzi (flow zone indicator) in µm can be defined by the following: 𝐹𝑍𝐼 = 𝑅𝑄𝐼 ∅𝑍 (3) the logarithm of both sides of the equation eq. 3 will lead to the final correlation, which is expressed as follows: 𝑙𝑜𝑔 𝑅𝑄𝐼 = 𝑙𝑜𝑔 ∅𝑍 + 𝑙𝑜𝑔 𝐹𝑍𝐼 (4) al-ajmi and holditch [16] stated that all samples with similar fzi values lie on a line with a slope of one in a log-log plot of rqi versus øz, while samples with equal fzi values but noticeably different from the earlier sample will lie on parallel lines with the same slope, as did perez [17]. samples parallel to one another have similar pore throat characteristics and make up a distinct hfu. each line refers to a single hfu, and the intercept of each line, øz, indicates the mean fzi for each hfu. each flow unit has a specific fzi [9]. 3generating a correlation between core porosity and core permeability depending on core measurements of porosity and permeability and a linear regression correlation between the log of core permeability and porosity, this classical equation has been established and explained in eq. 5. 𝑙𝑜𝑔 𝐾 = 16.129∅ − 1.984 (5) only 29 plugs from five wells were gathered from the jeribe reservoir because so few core samples were taken from this reservoir. fig. 1 shows the jeribe formation's core permeability and porosity's linear regression connection. the porosity-permeability relationship equation for the examined reservoir was created using the estimated relationship between porosity and permeability for the jeribe reservoir, which had a coefficient of determination (r2 = 0.519). fig. 1. permeability of core vs. the porosity of the core for jeribe formation/ jambour oil field 4determination of hydraulic flow unit numbers appling fzi technique to generate a relation between porosity and permeability utilizing the fzi methodology from core data, one must first extend these correlations to uncored interval wells applying to well logging data [18]. regression analysis is an important part of which these relationships are created [19]. after data screening with the use of (24 core plugs), this study generated the flow zone indicator (fzi) from core data and demonstrated the reservoir's flow unit magnitudes and distribution [9]. d. k. faidhllah and s. m. hamd-allah / iraqi journal of chemical and petroleum engineering 24,2 (2023) 65 70 67 eqs. 1, 2, and 3 are applied to porosity and permeability data collected from the core analysis where fzi will be obtained. then they will be grouped according to the fzi, which resulted in three hydraulic flow units, as shown in fig. 2. fig. 2. cross plot of core perm-porosity with fzi values in jeribe reservoir / jambour oil field a simplified analysis of the core permeability-porosity data shows the permeability-porosity relationship for every grouping depending on different fzi values in fig. 2. given that there are three hydraulic units in the jeribe reservoir, it's been shown that the application of generated permeability correlations in uncored wells depends on fzi values derived from the core subjected to statistical analysis. table 1 summarizes the permeability formulas that were created. table 1. permeability formulas from fzi values fzi equation r2 mean fzi fzi=0 k = 7.7537 ∅1.3061 0.784 0.342 fzi=1 k = 59.484 ∅1.7789 0.672 0.75 fzi=2-4 k = 653.37 ∅1.8875 0.969 3.23 5rqi versus øz log-log plot parallel lines can be seen in a plot of rqi vs z created using eqs. 1, 2, and 3. different core sample fzi values may show up on different lines [20]. as represented in fig. 3 got the same pore throat description and, as a result, the same flow unit for points placed on each line. the mean fzi for each group will be obtained from (24 core plugs) the log permeability will be estimated using the following formula [9]: 𝐾 = 1014(𝐹𝑍𝐼𝑚𝑒𝑎𝑛) 2 ∅𝑒 (𝑙𝑜𝑔) 3 (1−∅𝑒 (𝑙𝑜𝑔)) 2 (6) the jeribe reservoir was separated into three hydraulic flow units, according to the application of the fzi technique on the core samples, as shown by the three parallel lines in the generated rqi vs. øz plot in fig. 3. core samples with various fzi levels display entirely different lines. with the r2 values given in table 2, points that lie on each line had the same pore throat description and hence the same flow. fzi predicted permeability values would be applied to well (w-33) to determine the applicability of fzi by comparing fzi permeability to core permeability, as explained in fig. 4. fig. 3. reservoir quality index vs. normalized porosity cross plot for jeribe reservoir fig. 4. comparison between core permeability and predicted permeability by fzi d. k. faidhllah and s. m. hamd-allah / iraqi journal of chemical and petroleum engineering 24,2 (2023) 65 70 68 table 2. values of correlation coefficients got from reservoir quality index vs. normalized porosity relationship for each hydraulic flow unit fzi r2 fzi=0 0.938 fzi=1 0.782 fzi= (2-4) 0.857 6conclusions the correlation coefficient (0.519) is a result of the classical method in permeability estimation which shows weak linear regression between core porosity and core permeability and deals with this reservoir as one unit; as a result, this method is not applied to predict permeability. several hydraulic flow units are generated according to the application of the flow zone indicator approach in spite of the available number of core samples was not enough to be of high certainty and accuracy degree because of the faults that intersect this reservoir and appear among the wells that are cored, but it shows a good result with correlation coefficients of (0.969, 0.672, 0.784). jeribe reservoir is regarded as a reservoir with moderate-quality rock types in both the top and bottom units and a good-quality rock type in the middle unit. the small contrast of core permeability and predicted permeability by fzi demonstrates that the permeability equations obtained from fzi are suitable for use on uncored wells. nomenclature symbol description unit fzi flow zone indicator µm fzimean mean flow zone indicator µm hfu hydraulic flow unit -- hfus hydraulic flow units -- rqi reservoir quality index µm øz normalized porosity fraction k permeability md øe effective porosity fraction kcore core permeability md øcore core porosity fraction øe(log) effective porosity measured by log fraction references [1] man, h.q.; jarzyna, j. integration of core, well logging and 2d seismic data to improve a reservoir rock model: a case study of gas accumulation in the ne polish carpathian foredeep. geol. q.,2013, 57, pp. 289–306. https://doi.org/10.7306/gq.1091 [2] abed a. a., hamd-allah s. m. “comparative permeability estimation method and identification of rock types using cluster analysis from well logs and core analysis data in tertiary carbonate reservoir-khabaz oil field”, journal of engineering, college of engineering, university of baghdad, vol. 22, no. 12,2019, pp. 49-61. https://doi.org/10.31026/j.eng.2019.12.04 [3] mehdi bagheripour haghighi and mehdi shabaninejad, “a permeability predictive model based on hydraulic flow unit for one of iranian carbonate tight gas reservoir”, spe middle east unconventional gas conference and exhibition held in muscat, oman, january-february 2011. https://doi.org/10.2118/142183-ms [4] al-dulaimi, s. “biostratigraphy of qamchuqa formation in jambur oil field in kirkuk area”, journal of university of babylon for pure and applied sciences, vol.28, 2020, pp. 216-242. [5] abdula, r. a., nourmohammadi, m. s., rashed, g. r., saleh, n. q., “petrographical and microfacies study of jeribe formation (m. miocene) in ashdagh mountain, kurdistan region, iraq”. iraqi bulletin of geology and mining journal, vol. 13, no.1, 2017, pp. 107 – 118. [6] samaher a. l., sameera m. hamd-alla, and ali h. j., “permeability estimation for carbonate reservoir (case study/ south iraqi field)”, iraqi journal of chemical and petroleum engineering, college of engineering, university of baghdad, vol. 19, no. 3,2018, pp. 41-45. https://doi.org/10.31699/ijcpe.2018.3.5 [7] baker, h. a., al-jawad, s. n., murtadha, z. i., “permeability prediction in carbonate reservoir rock using fzi”. iraqi journal of chemical and petroleum engineering, vol. 14, no. 3, 2013, pp. 4954. [8] kumar, n., hughes, b., and frailey, s. m., “using well logs to infer permeability: will there ever be a permeability log?”, roceedings of the annual southwestern petroleum short course, 288-298, 2001. [9] abdul majeed, y. n., ramadhan, a. a., mahmood, a. j., “comparing between permeability prediction by using classical and fzi methods/tertiary reservoir in khabaz oil field / northern iraq”. iraqi journal of oil & gas research, vol. 2, no. 1, 2022. https://doi.org/10.55699/ijogr.2022.0201.1015 [10] waffa m. al-qattan, ahmed h. al mohammed. “permeability prediction by classical and flow zone indictor (fzi) methods for an iraqi gas field”, iraqi journal of chemical and petroleum engineering, vol. 18, no. 3, 2017, pp. 59-65. [11] salman, o., hasan, o. f., al-jawad, s., “permeability prediction in one of iraqi carbonate reservoir using statistical, hydraulic flow units, and ann methods”. iraqi journal of chemical and petroleum engineering, vol. 23, no. 4, 2022, pp. 1724. https://doi.org/10.31699/ijcpe.2022.4.3 [12] abdulelah, h., mahmood, s., hamada, g., “hydraulic flow units for reservoir characterization: a successful application on arab-d carbonate”. in iop conference series: materials science and engineering, vol. 380, no. 1, 2018, p. 012020. iop publishing. https://doi.org/10.1088/1757899x/380/1/012020 https://doi.org/10.7306/gq.1091 https://doi.org/10.31026/j.eng.2019.12.04 https://doi.org/10.2118/142183-ms https://www.journalofbabylon.com/index.php/jubpas/article/view/3382 https://www.journalofbabylon.com/index.php/jubpas/article/view/3382 https://www.journalofbabylon.com/index.php/jubpas/article/view/3382 https://www.journalofbabylon.com/index.php/jubpas/article/view/3382 https://www.iasj.net/iasj/download/f38d431f3d97b88c https://www.iasj.net/iasj/download/f38d431f3d97b88c https://www.iasj.net/iasj/download/f38d431f3d97b88c https://www.iasj.net/iasj/download/f38d431f3d97b88c https://www.iasj.net/iasj/download/f38d431f3d97b88c https://www.iasj.net/iasj/download/f38d431f3d97b88c https://doi.org/10.31699/ijcpe.2018.3.5 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/318 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/318 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/318 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/318 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/318 https://experts.illinois.edu/en/publications/using-well-logs-to-infer-permeability-will-there-ever-be-a-permea https://experts.illinois.edu/en/publications/using-well-logs-to-infer-permeability-will-there-ever-be-a-permea https://experts.illinois.edu/en/publications/using-well-logs-to-infer-permeability-will-there-ever-be-a-permea https://experts.illinois.edu/en/publications/using-well-logs-to-infer-permeability-will-there-ever-be-a-permea https://experts.illinois.edu/en/publications/using-well-logs-to-infer-permeability-will-there-ever-be-a-permea https://doi.org/10.55699/ijogr.2022.0201.1015 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/66 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/66 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/66 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/66 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/66 https://doi.org/10.31699/ijcpe.2022.4.3 https://doi.org/10.1088/1757-899x/380/1/012020 https://doi.org/10.1088/1757-899x/380/1/012020 d. k. faidhllah and s. m. hamd-allah / iraqi journal of chemical and petroleum engineering 24,2 (2023) 65 70 69 [13] hmeed, m. r. a., hamd-allah, s. m., “studying the effect of permeability prediction on reservoir history matching by using artificial intelligence and flow zone indicator methods”. the iraqi geological journal, vol. 56, no. 1e, 2023, pp. 9-21. https://doi.org/10.46717/igj.56.1e.2ms-2023-5-12 [14] el sharawy, m. s., “petrophysical characteristics of the nubia sandstone along the b –trend, southern gulf of suez, egypt, based on the hydraulic flow units concept”. journal of applied sciences research, vol. 9, no.7, 2013, pp. 4271-4287. [15] svirsky, d., a. ryazanov, m. pankov, p. corbett, a. posysoev. “hydraulic flow units reservoir description challenges in siberian oil field”. spe 87056,2004, pp.15. https://doi.org/10.2118/87056-ms [16] al-ajmi, fahad a., aramco, saudi, and stephen a. holditch. "permeability estimation using hydraulic flow units in a central arabia reservoir." spe annual technical conference and exhibition, dallas, texas, october 2000. https://doi.org/10.2118/63254ms [17] hector h. perez, akhil datta –gupta, (2003), “the role of electrofacies, lithfacies, and hydraulic flow units in permeability predictions from well logs: a comparative analysis using classification trees”, spe res eval & eng 8 (02): 143–155. https://doi.org/10.2118/84301-pa [18] uguru, c. i., onyeagoro, u. o., lin, j., okkerman, j., and i. o. sikiru. "permeability prediction using genetic unit averages of flow zone indicators (fzis) and neural networks." nigeria annual international conference and exhibition, 2005. https://doi.org/10.2118/98828-ms [19] mohammed b. alsinbili, sameer n. aljawad, ammar a. aldalawy. “permeability prediction of un-cored intervals using fzi method and matrix density grouping method: a case study of abughirab field/asmari fm., iraq”, iraqi journal of chemical and petroleum engineering, vol. 14, no. 4, 2013, pp. 27-34. [20] dahlia a. alobaidi. “permeability prediction in one of iraqi carbonate reservoir using hydraulic flow units and neural networks”, iraqi journal of chemical and petroleum engineering, vol. 17, no. 1, 2016, pp. 1-11. https://doi.org/10.46717/igj.56.1e.2ms-2023-5-12 https://d1wqtxts1xzle7.cloudfront.net/33535050/flow-libre.pdf?1398229913=&response-content-disposition=inline%3b+filename%3dflow_unit.pdf&expires=1688049018&signature=amwk0sejgbagmruocln3etf3fqqiveksczm6puku8yjz2qt3stf0v~ufmyuc-b-lvnu5il71i8fkj6gzyrtdvk0ukh~r7gxiacpkvbucqxfovb8dwnypjjotr5wzwcxfmjf5g5yatenj0tvcqkdlcs~f2xbswrb~mz87g1vwggvz4qi4wa1a3dzkhx-euezmn8koq~04-nzxavwmiw9zwazg3psvxyzkrhipxlvo5o0heet3w2tccycwrlhiqrj6gpgyxvbvc1elnnrmacuy-5zr7qgfxximfqt1ek~u0boqr5ygp8jbj71sqgvltklvzyyyeg3xycvt0qxyoljv3a__&key-pair-id=apkajlohf5ggslrbv4za 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https://d1wqtxts1xzle7.cloudfront.net/33535050/flow-libre.pdf?1398229913=&response-content-disposition=inline%3b+filename%3dflow_unit.pdf&expires=1688049018&signature=amwk0sejgbagmruocln3etf3fqqiveksczm6puku8yjz2qt3stf0v~ufmyuc-b-lvnu5il71i8fkj6gzyrtdvk0ukh~r7gxiacpkvbucqxfovb8dwnypjjotr5wzwcxfmjf5g5yatenj0tvcqkdlcs~f2xbswrb~mz87g1vwggvz4qi4wa1a3dzkhx-euezmn8koq~04-nzxavwmiw9zwazg3psvxyzkrhipxlvo5o0heet3w2tccycwrlhiqrj6gpgyxvbvc1elnnrmacuy-5zr7qgfxximfqt1ek~u0boqr5ygp8jbj71sqgvltklvzyyyeg3xycvt0qxyoljv3a__&key-pair-id=apkajlohf5ggslrbv4za https://doi.org/10.2118/87056-ms https://doi.org/10.2118/63254-ms https://doi.org/10.2118/63254-ms https://doi.org/10.2118/84301-pa https://doi.org/10.2118/98828-ms https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/323 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/323 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/323 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/323 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/323 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/323 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/323 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/85 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/85 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/85 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/85 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/85 d. k. faidhllah and s. m. hamd-allah / iraqi journal of chemical and petroleum engineering 24,2 (2023) 65 70 70 تخمين وحدات التدفق لمكمن الجريبي في حقل جمبور النفطي بتطبيق طريقة مؤشر وحدات الجريان 1 محمد حمدهللاسميرة و ، *1دريا خالد فيض هللا العراق، جامعة بغدادقسم هندسة النفط، كلية الهندسة، 1 الخالصة ت عالية في المتجانسة الذي ُيظهر إختالفات وتغيراالغير من المكامن الكاربونية المعقدة و يعد مكمن الجريبي د ة بالعدضئيل من اآلبار مقارنقليلة جدًا مأخوذة من عدد الصخرية المتوفرة عليه محدودة و اللبابالنفاذية، و ء لى بناابالتالي من أجل التنبؤ بالنفاذية لهذا التكوين تظهر الحاجة لآلبار الموجودة في حقل جمبور و الكلي قها تعميمها على الحقل من خالل تطبيو ،اآلبار الماخوذة لها لباب صخرية عالقات الرياضية باالعتماد على التي أظهرت إستخدامًا واسعًا في اآلونة األخيرة هي طريقة مؤشر وحداتعلى بقية اآلبار. إحدى الطرق ه دي. هذالتي من خاللها باإلمكان تقسيم المكمن المعني إلى عدد من وحدات التدفق في اإلتجاه العمو ان و الجري الدراسة تهدف الى بناء موديل للنفاذية مكمن الجريبي باإلعتماد على طريقة مؤشر وحدات الجريان. عن طريق تحليل اللباب الصخرية من خالل رسم مخطط لكل من النفاذية والمسامية المقاسة مختبرياً الجريبي إلىمخطط مؤشر جودة المكمن مع المسامية المحّسنة تم التوصل إلى إنه باإلمكان تقسيم مكمن و )صخور ذات نوعية جيدة، بالتالي فإنه يتكون من ثالث أنواع مختلفة من الصخورثالث وحدات للتدفق و ن الكلي التكويقلياًل جدًا مقارنة بئة الجودة ُتمثل جزءًا محدودًا و متوسطة الجودة، رديئة الجودة(. الصخور الردي ما تكوين الجريبي أبينما الصخور المتوسطة الجودة تظهر بشكل واضح في كل من الجزء العلوي و السفلي من .النوع الجيد من الصخور فيهمن المكمن تظهر الجزء االوسط .، التنبؤ بالنفاذيةجريبي، مؤشر وحدات الجريان، جمبور، وحدات التدفق الكلمات الدالة: available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.23 no.3 (september 2022) 43 – 49 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: ammar s. abbas, email: ammarabbas@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. kinetics and activation complex thermodynamic study of the acidity removal of oleic acid via esterification reaction on commercial 13x zeolite shahd i. jurmot and ammar s. abbas chemical engineering department, college of engineering, university of baghdad, baghdad, iraq abstract the study involved the removal of acidity from free fatty acid via the esterification reaction of oleic acid with ethanol. the reaction was done in a batch reactor using commercial 13x zeolite as a catalyst. the effects of temperatures (40 to 70 °c) and reaction time (up to 120 minutes) were studied using 6:1 mole ratio of pure ethanol to oleic acid and 5 wt. % of the catalyst. the results showed that acid removed increased with increasing temperature and reaction time. also, the acidity removal rises sharply during the first reaction period and then changes slightly afterward. the highest acidity removal value was 67 % recorded at 110 minutes and 70 °c. an apparent homogeneous reversible reaction kinetic model has been proposed and solved with the experimentally obtained kinetics data to evaluate reaction rate constants versus temperature, pre-exponential factors, and activation energy values for the forward and the backward esterification reactions. the activation energies were 34.863 kj/mol for the forward reaction and 29.731 kj/mol for the backward reaction. the thermodynamics of the activation step of the forward and reverse reactions was studied based on the hypothesis of forming a complex material that decomposes into a product. the activation steps were studied using eyring bimolecular collision theory approach, and both δh* and δs* were determined for forward and backward esterification reactions. the enthalpies of activation were 32.141 kj/mol and 27.080 kj/mol for the forward reaction and the backward reaction, and the entropies of activation were 193.7 and -212.7 j/mol. k for the forward reaction and the backward reaction, respectively. keywords: esterification, biodiesel, kinetics, arrhenius, eyring, activation step. received on 28/06/2022, accepted on 26/08/2022, published on 30/09/2022 https://doi.org/10.31699/ijcpe.2022.3.6 1introduction energy derived from fossil energy sources (coal, oil, and gas) or nuclear supplies is mainly responsible for the greenhouse effect, acid rain, and other negative impacts on health and the environment [1,2]. the continuation of the recent trend in energy demand and unsustainable ways of using it due to population increase and expectations of increased demand for it in the foreseeable future will mean the continuation of environmental problems and their harmful health effects on life [3]. sustainable and renewable energies provided a vital opportunity to cover part of the energy requirements with little or no negative impacts on the environment and health [3,4]. renewable energy produces from converting natural resources or materials that are recultivated or reproduced into acceptable forms of energy and are considered essential solutions in reducing the depletion of fossil resources with negative impacts. the most critical technical solutions are solar radiation, wind, falling water, gravitational forces, geothermal heat, and biomass [5]. biofuel is one of the by-products of using and converting biomass and is one of the crucial solutions for energy alternatives. biodiesel is a product that attracts international attention. it is the alkyl ester of a long-chain fatty acid derived from a renewable lipid feedstock, such as vegetable oils or animal fats [6,7]. the biodegradable and non-toxic biodiesel offers an excellent alternative to fossil fuels or as an essential addition [8,9] that contributes to reducing fuel consumption and harmful emissions and its lubricating properties, which contribute to preserving the environment [10]. biodiesel is produced by oils and fats that react with short-chain alcohol (methanol or ethanol) through a transesterification reaction, producing alkyl esters with glycerol using a base catalyst. also, biodiesel is made from the esterification reaction, which produces alkyl citrate and water using an acid catalyst [11]. in esterification reactions, homogeneous acid catalysts (such as sulfuric acid, methane-sulfonic acid, phosphoric acid, trichloroacetic, and hydrochloric acids) are used [12,13]. also, the heterogeneous catalysts are used in the esterification reactions, which do not cause corrosion problems in equipment and reduce the cost of separating the products later [13]. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:ammarabbas@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2022.3.6 s. i. jurmot and a. s. abbas / iraqi journal of chemical and petroleum engineering 23,3 (2022) 43 49 44 zeolites are valuable catalysts used in many processes, including biodiesel production by the esterification reaction. the importance of zeolite is due to its distinctive properties, including its high and tunable acidity, relatively high surface area, high thermal stability, and the size of microporous pores, which allow a smooth transfer of the reactant and product compounds through it [11– 13]. various types of zeolites have been as catalysts in the study of the esterification reaction such as; nay zeolite [9,14], hy zeolite [15,17], zsm-5 [18], fau-type zeolite [19], modified zsm-5, and 13x zeolite and its modified version [12,20]. this work aims to examine the kinetics of the esterification of oleic acid with ethanol by using commercial 13x zeolite (c13xz). the study used the elimination of acidity as an indication for the conversion of oleic acid, followed by an analysis of the kinetics of the esterification reaction, which found reaction rate constants at various temperatures and with varying activation energies. finally, a thorough investigation discovered the enthalpy and entropy of the esterification reaction of the activation step. 2experimental work the esterification reaction was carried out in a hemispherical flask of 500 ml with a 3-neck flask. the central neck was close-fitting with a water-cooled condenser. a thermometer fixed in the second neck measured the reaction mixture temperature, while the third neck was closed with a movable stopper. an electromagnetic hot plate (mr hei-standared / germany) was used to stir and heat the reaction mixture, as in fig. 1. fig. 1. schematic diagram of the batch reactor the reactor was loaded with 150 ml (0.475 mol) of oleic acid and the required volume of pure ethanol (166.4 ml) to have the initial molar ratio of ethanol to oleic acid 6/1. the agitation was kept at 300 rpm, which is necessary to increase the contact surface between ethanol and oil because ethanol and oil are immiscible. the reaction mixture was heated to the preferred temperature (40 to 70 °c). after that, the 5 wt.% of c13xz catalyst based on the oleic acid weight was added, and the reaction time recorded. the authors measured the properties of the used catalyst in the esterification reaction and summarized in table 1. table 1. c13xz catalyst properties property si/al bet surface area, m 2 /g pore volume, cm 3 /g na content, % value 4.3 551.16 0.24 6.81 a sample of 2 ml was taken via a syringe at different intervals, and to get good phase separation, the sample was centrifuged for 10 min at 3000 rpm. then upper layer (organic phase) was titrated with 0.1 n koh and by using phenolphthalein as an indicator to obtain the acid value (av) in eq. (1). 56.1 ml of koh n av weight of sample    (1) the acidity removal fraction (e) was calculated using eq. (2).   o o av av e av   (2) where: av0 is the initial acid value (acid number value for oleic acid: 197.35 ml koh/g), and av is the acid value at time (t) in minutes. 3results and discussion 3.1. kinetics study the results of the esterification of oleic acid, which was studied in the temperature range between 40 and 70 °c for about two hours, and presented in fig. 2, show that the fraction of acidity removal increases dramatically during the first 20 minutes. the reason for this sharp increase is due to the absence of water molecules in the pores of the catalyst, which results from the reaction, allowing a rapid reaction of oleic acid on the clean and large number of active sites, and the decrease in acidity in the first period of the reaction [14, 21]. after that, the values of the acidity removal rise slightly to the end of the reaction time (less than 2 h). the increase in the esterification temperature positively affected the acidity removal of oleic acid. the highest recorded value of acidity removal was 67% at 70 ºc and 110 min. the increase in acidity removal with temperature belongs to the rise in the collision’s frequency of reactant molecules causing growth in the probability of collision of molecules that carry the required activation energy to complete the esterification reaction [22]. s. i. jurmot and a. s. abbas / iraqi journal of chemical and petroleum engineering 23,3 (2022) 43 49 45 fig. 2. oleic acid acidity removal versus time at different esterification reaction temperatures using 6/1 pure ethanol/oleic acid initial molar ratio and 5 wt. % c13xz the kinetic of the esterification reaction was studied in terms of acidity removal value (e). the stoichiometric equation of the esterification reaction could be clarified in eq. (3). 5 517 33 2 17 33 2 2 +c h cooh c h oh c h cooc h h o (3) eq. (3) can be expressed symbolically as eq. (4). 1 2 k a b c d k   (4) a pseudo-homogeneous reversible with a single-step esterification reaction was assumed. also, the first order for all the reactants and products was assumed, and the noncatalyzed reaction rates were neglected. the pseudohomogeneous reversible reaction rate can be represented as eq. (5). [ ] [ ] [ ] [ ] 1 2 da r k a b k c d a dt     (5) where: [a] is the concentration of oleic acid (initially, 1.5 mol/l); [b] is the concentration of the ethanol, [c] and [d] were the concentrations of produced biodiesel and water, respectively. in terms of acidity removal (e), eq. (5) can be written as eq. (6).    2 2 211 2 bde o r a k a e e k a eo o oa dt ao               (6) the solving of eq. (6) was carried out using the differential method approach with the least squares’ method, and it was started by substituting the initial molar ratio of ethanol to oleic acid ( o o b a = 6/1) and utilizing the obtained kinetics data. the reaction rate constants for forward and backward reactions (k1 and k2) and the correlation coefficients (r 2 ) at different temperatures were calculated and summarized in table 2. table 2. constant values of the esterification reaction kinetic model for the forward and the backward reaction and values of the correlation coefficient temp. ºc k1, l/mol. min k2, l/mol. min r 2 , 40 0.00097 0.00075 0.9521 50 0.00165 0.00161 0.9499 60 0.00219 0.00191 0.9474 70 0.00279 0.00257 0.9412 the results indicated that the reaction constants increase with temperature and that the values of the forward reaction constants were consistently higher than the values of the back reaction, which indicates the continuity of acid removal in this range of temperatures. the highest value of k was 0.00279 l/mol. min. at 70 ºc for the forward reaction and 0.00257 l/mol. min. for the backward reaction at the same temperature. arrhenius law (eq. 7) [23] was plotted (figure 3) and used to evaluate the effect of temperature on the rates of chemical reactions. activation energies for the forward and the backward reactions and frequency factors values have been calculated and summarized in table 3. ln( ) ln( ) e ai k ai i rt   (7) where: ki is the reaction rate constant for the forward and the backward reactions, ai is the pre-exponential factor for the forward and the backward reactions, eai is the reaction activation energy for the forward and the backward reactions, r is the general gas constant, and t is the absolute reaction temperature (in kelvins). fig. 3. arrhenius plot for esterification reaction of oleic acid with ethanol using c13xz s. i. jurmot and a. s. abbas / iraqi journal of chemical and petroleum engineering 23,3 (2022) 43 49 46 table 3. activation energies (eai) and frequency factors (a0) for forward and backward reaction reaction eai, kj/mol a0, l/mol. min r 2 , forward (1) 34.863 564.08 0.9157 backward (2) 29.731 140.69 0.9664 the calculated activation energies were close to the results of the previous research [12], which adopted the analysis of a heterogeneous model of the esterification process of oleic acid over modified and prepared 13x zeolite. the reason for this convergence of the activation energies of the esterification process of oleic acid may be due to the similarity of the physicochemical properties of the commercial catalyst (used in this research) with those properties that the researchers [12] reached after the preparation and modification process, especially the ratio of silica to alumina. the obtained activation energies were within the same magnitude as the activation energies (28.6 to 42.6 kj/mol) found using different zeolites [14, 17]. 3.2. thermodynamic study the thermodynamics of the esterification process was studied using eyring bimolecular collision (eq. 8) [24], and activated complex of relatively high energy was generated with a certain change in enthalpy (δh*) and the change entropy (δs*). the same approach was used for the forward and backward reactions. * * exp exp b i k t h s k h rt r                (8) where: kb is boltzmann's constant (1.381×10 -23 j/k), h is planck's constant (6.626×10 -34 j.s), r is the gas constant, and t is the absolute temperature in kelvin (k). fig. 4. eyring plot for forward and backward esterification reactions of oleic acid with ethanol using c13xz the plot of ln (ki/t) versus 1/t for the values of reaction rate constants for forward and backward reactions (fig. 4), produced a straight-line (for each reaction) with a negative slope equal to δh*/rt and intercept equal to δs*/r + ln kb/h. the obtained values of the δh* and δs* were listed in table 4. table 4. obtained δh* and δs* for forward and backward esterification reactions reaction δh*, kj/mol δs*, j/mol. k r 2 , forward 32.141 -193.7 0.9017 backward 28.080 -212.7 0.9658 the positive values of δh* showed that both the forward and the backward esterification reactions were endothermic. the higher value of δh* of the forward reaction indicated that the heat was a critical parameter for the esterification reaction. the change in δs* had a negative quantity for both esterification reactions because the reactant molecules combine to form a single activated complex, leading to decreasing in molecules of the system and reducing in entropy [24]. 4conclusions in this study, the acidity of free fatty acids can be effectively removed by the esterification reaction of oleic with ethanol utilizing c13xz. the removal of acidity was rapid in the first reaction period because the catalyst was clean, and its active sites were not filled with produced water that breakdown the forward reaction. the removal of acidity of oleic acid was increased with increasing temperature along the time of reaction because of the increase in the collision’s frequency of reactant molecules. a 67% was the maximum value of the acidity removal recorded at 70 ºc and 110 min with a 6/1 mole ratio of ethanol/oleic acid and 5% wt. c13xz. the kinetic parameters of the suggested model were obtained involving reaction rate constants, pre-exponential factors, and activation energies for the forward and the backward esterification reactions. the activation energies obtained through fitting the kinetic model with the experimental results were 34.863 kj/mol for the forward reaction and 29.731 kj/mol for the backward reaction. the thermodynamic study of the activation step has been investigated using the eyring bimolecular collision theory approach. the enthalpies of the activation step showed that the acidity removal process onto c13xz was endothermic; the value was 32.141 kj/mol for the forward reaction and 27.080 kj/mol for the backward reaction. the entropies of activation were -193.7 and -212.7 j/mol. k for the forward reaction and the backward reaction, respectively. s. i. jurmot and a. s. abbas / iraqi journal of chemical and petroleum engineering 23,3 (2022) 43 49 47 nomenclature no. symbol meaning 1 [a] the concentration of oleic acid (mol/l). 2 [a0] the initial concentration of oleic acid (mol/l). 3 ai the pre-exponential factor for the forward and the backward reactions (l/mol. min). 4 [b] the concentration of the ethanol (mol/l). 5 [b0] the initial concentration of the ethanol (mol/l). 6 [c] the concentration of produced biodiesel (mol/l). 7 [d] the concentration of produced water (mol/l). 8 e acidity removal fraction (-). 9 eai the activation energy for the forward and the backward reactions (j/mol). 10 h planck's constant (6.626×10-34 j.s). 11 δh* change in enthalpy (j/mol). 12 ki the reaction rate constant for the forward and the backward reactions (l/mol. min). 13 kb boltzmann's constant (1.381×10-23 j/k). 14 r the general gas constant (8.314 j/mol. k). 15 r 2 correlation coefficient (-). 16 δs* the change in entropy (j/mol. k). 17 t time (min.). 18 t the absolute reaction temperature (in kelvins). abbreviations no. symbol meaning 1 av acid value. 2 av0 the initial acid value. 3 c13xz commercial 13 x zeolite. references [1] d. seifried and w. witzel, renewable energy: the facts. london: earthscan, 2010. [2] m. a. hanif, f. nadeem, r. tariq, and u. r. institute, renewable and alternative energy resources. london: academic press, 2022. [3] v. quaschning, understanding renewable energy systems. london: earthscan, 2016. [4] s. boslaugh, alternative energy resources (solar). the registered company springer nature switzerland ag, 2021. [5] g. national and h. pillars, biodiesel: a realistic fuel alternative for diesel engines. springer-verlag london limited apart, 2008. [6] m. berrios, m. a. martín, a. f. chica, and a. martín, “study of esterification and transesterification in biodiesel production from used frying oils in a closed system,” chem. eng. j., vol. 160, no. 2, pp. 473–479, 2010, doi: 10.1016/j.cej.2010.03.050. [7] g. knothe, “biodiesel and renewable diesel: a comparison,” prog. energy combust. sci., vol. 36, no. 3, pp. 364–373, 2010, doi: 10.1016/j.pecs.2009.11.004. [8] w. liu, p. yin, j. zhang, q. tang, and r. qu, “biodiesel production from esterification of free fatty acid over pa / nay solid catalyst,” energy convers. manag., vol. 82, pp. 83–91, 2014, doi: 10.1016/j.enconman.2014.02.062. [9] a. s. abbas and r. n. abbas, “preparation and characterization of nay zeolite for biodiesel production,” iraqi j. chem. pet. eng., vol. 16, no. 2, pp. 19–29, 2015 [10] o. e. ajala, f. aberuagba, t. e. odetoye, and a. m. ajala, “biodiesel: sustainable energy replacement to petroleum-based diesel fuel – a review,” chembioeng rev., vol. 2, no. 3, pp. 145– 156, 2015, doi: 10.1002/cben.201400024. [11] a. s. abbas and t. s. othman, “production and evaluation of biodiesel from sheep fats waste,” iraqi j. chem. pet. eng., vol. 13, no. 1, pp. 11–18, 2012. [12] b. a. alshahidy and a. s. abbas, “comparative study on the catalytic performance of a 13x zeolite and its dealuminated derivative for biodiesel production,” bull. chem. react. eng. catal., vol. 16, no. 4, pp. 763–772, 2021, doi: 10.9767/bcrec.16.4.11436.763-772. [13] s. k. a. barno, s. a. rashid, and a. s. abbas, “modeling and simulation of an ideal plug flow reactor for synthesis of ethyl oleate using homogeneous acid catalyst,” chem. process eng. inz. chem. i proces., vol. 42, no. 1, p. 53, 2021, doi: 10.24425/cpe.2021.137339. [14] a. s. abbas and r. n. abbas, “kinetic study and simulation of oleic acid esterification over prepared nay zeolite catalyst,” iraqi j. chem. pet. eng., vol. 14, no. 4, pp. 35–43, 2013. [15] a. s. abbas, t. m. albayati, z. t. alismaeel, and a. m. doyle, “kinetics and mass transfer study of oleic acid esterification over prepared nanoporous hy zeolite,” iraqi j. chem. pet. eng., vol. 17, no. 1, pp. 47–60, 2016. [16] a. m. doyle, t. m. albayati, a. s. abbas, and z. t. alismaeel, “biodiesel production by esterification of oleic acid over zeolite y prepared from kaolin,” renew. energy, vol. 97, pp. 19–23, 2016, doi: 10.1016/j.renene.2016.05.067. [17] z. t. alismaeel, a. s. abbas, t. m. albayati, and a. m. doyle, “biodiesel from batch and continuous oleic acid esterification using zeolite catalysts,” fuel, vol. 234, no. april, pp. 170–176, 2018, doi: 10.1016/j.fuel.2018.07.025. [18] a. alnaama, “synthesis and characterization of nanocrystalline zsm-5 and zsm-5 / mcm-41 composite zeolite for biodiesel production,” vol. 17, no. march, pp. 71–82, 2015. https://books.google.com/books?hl=en&lr=&id=hq5ej7llrl8c&oi=fnd&pg=pp5&dq=%5b1%5d+d.+seifried+and+w.+witzel,+renewable+energy:+the+facts.+london:+earthscan,+2010.&ots=rugkugxt55&sig=3thzl48hftjshjfkp90yuinw-wk https://books.google.com/books?hl=en&lr=&id=hq5ej7llrl8c&oi=fnd&pg=pp5&dq=%5b1%5d+d.+seifried+and+w.+witzel,+renewable+energy:+the+facts.+london:+earthscan,+2010.&ots=rugkugxt55&sig=3thzl48hftjshjfkp90yuinw-wk https://www.taylorfrancis.com/books/mono/10.4324/9781315769431/understanding-renewable-energy-systems-volker-quaschning https://www.taylorfrancis.com/books/mono/10.4324/9781315769431/understanding-renewable-energy-systems-volker-quaschning https://www.sciencedirect.com/science/article/pii/s1385894710009393 https://www.sciencedirect.com/science/article/pii/s1385894710009393 https://www.sciencedirect.com/science/article/pii/s1385894710009393 https://www.sciencedirect.com/science/article/pii/s1385894710009393 https://www.sciencedirect.com/science/article/pii/s1385894710009393 https://www.sciencedirect.com/science/article/pii/s0360128509000677 https://www.sciencedirect.com/science/article/pii/s0360128509000677 https://www.sciencedirect.com/science/article/pii/s0360128509000677 https://www.sciencedirect.com/science/article/pii/s0360128509000677 https://www.sciencedirect.com/science/article/pii/s0196890414001812 https://www.sciencedirect.com/science/article/pii/s0196890414001812 https://www.sciencedirect.com/science/article/pii/s0196890414001812 https://www.sciencedirect.com/science/article/pii/s0196890414001812 https://www.sciencedirect.com/science/article/pii/s0196890414001812 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/251 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/251 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/251 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/251 https://onlinelibrary.wiley.com/doi/abs/10.1002/cben.201400024 https://onlinelibrary.wiley.com/doi/abs/10.1002/cben.201400024 https://onlinelibrary.wiley.com/doi/abs/10.1002/cben.201400024 https://onlinelibrary.wiley.com/doi/abs/10.1002/cben.201400024 https://onlinelibrary.wiley.com/doi/abs/10.1002/cben.201400024 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/329 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/329 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/329 https://ejournal2.undip.ac.id/index.php/bcrec/article/view/11436 https://ejournal2.undip.ac.id/index.php/bcrec/article/view/11436 https://ejournal2.undip.ac.id/index.php/bcrec/article/view/11436 https://ejournal2.undip.ac.id/index.php/bcrec/article/view/11436 https://ejournal2.undip.ac.id/index.php/bcrec/article/view/11436 https://ejournal2.undip.ac.id/index.php/bcrec/article/view/11436 https://yadda.icm.edu.pl/baztech/element/bwmeta1.element.baztech-0fdde2d9-ef33-4127-8977-3d314f3aa13a https://yadda.icm.edu.pl/baztech/element/bwmeta1.element.baztech-0fdde2d9-ef33-4127-8977-3d314f3aa13a https://yadda.icm.edu.pl/baztech/element/bwmeta1.element.baztech-0fdde2d9-ef33-4127-8977-3d314f3aa13a https://yadda.icm.edu.pl/baztech/element/bwmeta1.element.baztech-0fdde2d9-ef33-4127-8977-3d314f3aa13a https://yadda.icm.edu.pl/baztech/element/bwmeta1.element.baztech-0fdde2d9-ef33-4127-8977-3d314f3aa13a https://yadda.icm.edu.pl/baztech/element/bwmeta1.element.baztech-0fdde2d9-ef33-4127-8977-3d314f3aa13a https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/324 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/324 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/324 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/324 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/89 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/89 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/89 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/89 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/89 https://www.sciencedirect.com/science/article/pii/s0960148116304773 https://www.sciencedirect.com/science/article/pii/s0960148116304773 https://www.sciencedirect.com/science/article/pii/s0960148116304773 https://www.sciencedirect.com/science/article/pii/s0960148116304773 https://www.sciencedirect.com/science/article/pii/s0960148116304773 https://www.sciencedirect.com/science/article/pii/s0016236118312250 https://www.sciencedirect.com/science/article/pii/s0016236118312250 https://www.sciencedirect.com/science/article/pii/s0016236118312250 https://www.sciencedirect.com/science/article/pii/s0016236118312250 https://www.sciencedirect.com/science/article/pii/s0016236118312250 s. i. jurmot and a. s. abbas / iraqi journal of chemical and petroleum engineering 23,3 (2022) 43 49 48 [19] g. j. gomes, d. m. dal pozzo, m. f. zalazar, m. b. costa, p. a. arroyo, and p. r. s. s. bittencourt, “oleic acid esterification catalyzed by zeolite ymodel of the biomass conversion,” top. catal., vol. 62, no. 12–16, pp. 874–883, 2019, doi: 10.1007/s11244-019-01172-3. [20] b. a. alshahidy and a. s. abbas, “preparation and modification of 13x zeolite as a heterogeneous catalyst for esterification of oleic acid,” aip conf. proc., vol. 2213, no. march, 2020, doi: 10.1063/5.0000171. [21] e. m. flanigen, r. w. broach, and a. steph, zeolites in industrial separation and catalysis. wiley-vch verlag gmbh and co. kga, 2010. [22] h. s. fogler and ame and catherine vennema professor of chemical engineering and the arthur f. thurnau professor, elements of chemical reaction engineering, fifth. 2019. [23] o. levenspiel, chemical reaction engineering, 3rd ed. john wiley and sons, 1999. [24] r. chang, physical chemistry for the biosciences. california: university science books mill valley, california, 2005. https://link.springer.com/article/10.1007/s11244-019-01172-3 https://link.springer.com/article/10.1007/s11244-019-01172-3 https://link.springer.com/article/10.1007/s11244-019-01172-3 https://link.springer.com/article/10.1007/s11244-019-01172-3 https://link.springer.com/article/10.1007/s11244-019-01172-3 https://link.springer.com/article/10.1007/s11244-019-01172-3 https://aip.scitation.org/doi/abs/10.1063/5.0000171 https://aip.scitation.org/doi/abs/10.1063/5.0000171 https://aip.scitation.org/doi/abs/10.1063/5.0000171 https://aip.scitation.org/doi/abs/10.1063/5.0000171 https://aip.scitation.org/doi/abs/10.1063/5.0000171 https://books.google.com/books?hl=en&lr=&id=_g6ov87inikc&oi=fnd&pg=pr5&dq=%5b21%5d%09e.+m.+flanigen,+r.+w.+broach,+and+a.+steph,+zeolites+in+industrial+separation+and+catalysis.+wiley-vch+verlag+gmbh+and+co.+kga,+2010.&ots=-lrg05rvw9&sig=0yixs_ouljqxokbwqxd8rbutpa8 https://books.google.com/books?hl=en&lr=&id=_g6ov87inikc&oi=fnd&pg=pr5&dq=%5b21%5d%09e.+m.+flanigen,+r.+w.+broach,+and+a.+steph,+zeolites+in+industrial+separation+and+catalysis.+wiley-vch+verlag+gmbh+and+co.+kga,+2010.&ots=-lrg05rvw9&sig=0yixs_ouljqxokbwqxd8rbutpa8 https://books.google.com/books?hl=en&lr=&id=_g6ov87inikc&oi=fnd&pg=pr5&dq=%5b21%5d%09e.+m.+flanigen,+r.+w.+broach,+and+a.+steph,+zeolites+in+industrial+separation+and+catalysis.+wiley-vch+verlag+gmbh+and+co.+kga,+2010.&ots=-lrg05rvw9&sig=0yixs_ouljqxokbwqxd8rbutpa8 https://books.google.com/books?hl=en&lr=&id=vw48eaaaqbaj&oi=fnd&pg=pp1&dq=%5b23%5d%09o.+levenspiel,+chemical+reaction+engineering,+3rd+ed.+john+wiley+and+sons,+1999.&ots=5x10lr7u9a&sig=shc3wci0aipcbtsznzw3yk0okqo https://books.google.com/books?hl=en&lr=&id=vw48eaaaqbaj&oi=fnd&pg=pp1&dq=%5b23%5d%09o.+levenspiel,+chemical+reaction+engineering,+3rd+ed.+john+wiley+and+sons,+1999.&ots=5x10lr7u9a&sig=shc3wci0aipcbtsznzw3yk0okqo https://books.google.com/books?hl=en&lr=&id=pnh1fhj5tw0c&oi=fnd&pg=pr13&dq=physical+chemistry+for+the+biosciences&ots=jzoji_ru5a&sig=ypvpjueiiubtfgsziphfndrkic8 https://books.google.com/books?hl=en&lr=&id=pnh1fhj5tw0c&oi=fnd&pg=pr13&dq=physical+chemistry+for+the+biosciences&ots=jzoji_ru5a&sig=ypvpjueiiubtfgsziphfndrkic8 https://books.google.com/books?hl=en&lr=&id=pnh1fhj5tw0c&oi=fnd&pg=pr13&dq=physical+chemistry+for+the+biosciences&ots=jzoji_ru5a&sig=ypvpjueiiubtfgsziphfndrkic8 s. i. jurmot and a. s. abbas / iraqi journal of chemical and petroleum engineering 23,3 (2022) 43 49 49 دراسة حركية و ثرموديناميكية المعقد المنشط الزالة الحامضية من حامض االوليك عبر 13x تفاعل االسترة باستخدام زيواليت تجاري نوع عمار صالح عباس وشهد عماد جرمط جامعة بغداد -كلية الهندسة -قسم الهندسة الكيمياوية الخالصة تناولت هذة الدراسة ازالة الحموضة من الحوامض الدهنية بواسطة اجراء تفاعل االسترة في مفاعل دفعي ( و بدرجات 6:1تم تطبيقة على حامض االوليك و االيثانول بنسبة ) 13×باستخدام عامل مساعد نوع زيواليت بًة الى وزن حامض االوليك و % من العامل المساعد نس 5( درجة سليزية و اضافة 70-40حرارة مختلفة ) دقيقة. اظهرت النتائج ان كمية الحامضية المزالة ازدادت مع ارتفاع درجة الحرارة 120كان زمن التفاعل بحدود و ان االزالة كانت بمعدل عالي في بداية التفاعل ثم استقرت. تم تسجيل اعلى قيمة الزالة الحامضية بمقدار دقيقة من زمن التفاعل. تم دراسة حركية التفاعل على انه تفاعل 110درجة مئوية و 70% بظروف 67 عكسي و ايجاد معادلة حركية التفاعل و ثوابت سرعة التفاعل و المعامالت االسية للمعادلة، كما تم حساب طاقة التنشيط لكال التفاعلين االمامي و العكسي بواسطة قانون ارينوس. كانت قيم طاقة التنشيط للتفاعل مول للتفاعل العكسي .كذلك تناولت الدراسة دراسة \كيلوجول 29.731مول و \كيلوجول 34.863المامي هي ا خطوة التنشيط للتفاعلين االمامي و العكسي و حساب الخواص الثرمودينامكية )االنثالبي و االنتروبي( بتطبيق ط. اظهرت نتائج الخواص الثرمودينامكية ان نظرية ارينك للتصادم الثنائي للجزيئة و بفرضية تكوين المعقد المنش 27.080مول للتفاعل االمامي و و\كيلوجول 32.141التفاعل ماص للحرارة و كانت قيم انثالبي التنشيط مول كلفن للتفاعل االمامي و \جول -212.7و -193.7مول للتفاعل العكسي وقيم انتروبي التنشيط \كيلوجول التفاعل العكسي على الترتيب. : تفاعل االسترة، الوقود الحيوي، حركية التفاعل، معادلة ارينوس، معادلة ارينك، خطوة التنشيط.دالة الكلمات ال iraqi journal of chemical and petroleum engineering vol.18 no.4 (december 2017) 25 33 issn: 1997-4884 evaluation of acid and hydraulic fracturing treatment in halfaya oil field-sadi formation jalal abdulwahid al-sudani and khalid munaf husain university of baghdad petroleum engineering abstract sadi formation is one of the main productive formations in some of iraqi oil fields. this formation is characterized by its low permeability values leading to low production rates that could be obtained by the natural flow. thus, sadi formation in halfaya oil field has been selected to study the success of both of "acid fracturing" and "hydraulic fracturing" treatments to increase the production rate in this reservoir. in acid fracturing, four different scenarios have been selected to verify the effect of the injected fluid acid type, concentration and their effect on the damage severity along the entire reservoir. the reservoir damage severity has been taken as "shallow–medium– severe" and (medium–severe-sallow) for better fluid invasion. while, in hydraulic fracturing, a three cases have been selected using three different main fracturing fluid and three different proppant size and types, to verify their effects on fracturing efficiency, and dimensionless fracture conductivity. the results show that both treatments have successful results, but the hydraulic fracturing gives about (1.5) times greater than acid fracturing. however, the maximum dimensionless fracture conductivity reached by all the treatments was about (fcd = 4) , with fracture efficiency reached to (82%). key words: hydraulic fracturing, acidizing, well damage, stimulation introduction well stimulation process is the most conventional way that could be adapted to increase well productivity; well stimulation could be performed either by “acidizing” or through “hydraulic fracturing "of the productive formation. the first term of “acidizing” may refers to “matrix acidizing” process if the injected acids used below the formation fracturing pressure and “acid fracturing” process if the injected acids used above the formation fracturing pressure. however hydraulic fracturing refer to treatment method which aim is to increase well productivity by creating fracture conductivity in the reservoir formation. in 1896 , a new patent by heman frasch (1), when he used hydrochloric acid for treatment limestone formation ,this reaction will produce two soluble chemical compounds : calcium university of baghdad college of engineering iraqi journal of chemical and petroleum engineering evaluation of acid and hydraulic fracturing treatment in halfaya oil field-sadi formation 26 ijcpe vol.18 no.4 (dec. 2017) -available online at: www.iasj.net chloride and carbon dioxide , and after this process the acid remove from well in the same way of producing well fluids. harris (2) in 1961, brought the use of acetic acid to the stimulation operation. because acetic acid is less corrosive than hcl, it was suggested that it could replace hcl in specific applications, especially at high temperatures. later, formic acid was also found to take place in solving certain problems immanent to acidizing with hcl. while, harris (3) in 1966, described the effects of acid concentration and the practical appearance of using high concentrations of hcl . experimental studies showed that the properties of mixture containing greater than 15% hcl had considerably different properties than solutions with lower concentration of hcl. practical experience proved in many cases that , the different properties of higher-concentration hcl solutions were beneficial to acidizing carbonates. it was approved that deeper acid penetration could be achieved with the higher-concentration solutions. use of mixtures such as 20%hcl and 28%hcl became common. hydraulic fracturing is probably the most widely used stimulation technique in the world today. hydraulic fracturing is a well-known technology, which was originally applied to overcome near wellbore skin damage and to increase oil and gas productivity by making conductive fractures in the reservoir. jurairat (4), used forcheimer equation to estimate fracture conductivity for both before and after acidizing. the cell pressure and pressure drop were recorded at each flow rate under each closure stress. by calculating fracture conductivity profile can be evaluated the effect of the acid on the fracture conductivity. economides and nolte, (5), prevailed that the two common methods of hydraulic fracturing are acid fracturing and proppant fracturing. the combined aim for the two methods is to increase well productivity by creating fracture conductivity in the reservoir formation. for assessment which method of hydraulic fracturing stimulation is giving the best response in carbonate formation, it can be obtained by making a comparison between applying acid fracturing and proppant fracturing and evaluate the results. they are indicated that the hydraulic fracturing has been expanded to such applications as reservoir stimulation for increased hydrocarbon deliverability, increased drainage area, and decreased pressure drop around the well to minimize problems with asphaltene5 and/or paraffin deposition. rajappa et al. (6), prevailed that propped hydraulic fracturing provided higher estimated optimal recovery and higher production rates, but it is more expensive than acid fracturing jobs. experimental work in this study, two major techniques have been employed to increase well production rates in halfaya field/sadi reservoir. these techniques are: 1acid fracturing treatment. 2hydraulic fracturing treatment. advance computer software "stim and frac" have been used to design, analyze and forecast the production capacity that may be obtained throughout utilizing these techniques. 1acid fracturing treatment as well as the formation temperature (155 °f) is suitable for this job trail. however, the activity of this process is high affected by acid concentration and the divergent type and the severity of formation damage. jalal abdulwahid al-sudani and khalid munaf husain -available online at: www.iasj.net ijcpe vol.18 no.4 (dec. 2017) 27 therefore, several cases have been created for several of formation damage severity and also for different acid concentrations to verify its efficiency in increasing reservoir production capacity.these cases can be listed as follows; case-1; well completion: open hole, damage only, main treatment acid: 15% hcl, skin type: shallow to medium damage, treatment stages: 3 stages preflush, input data: foam injection: shallow-med-deep. fig. 1, real-time operation for acid fracturing, case 1 case-2; well completion: open hole with deep wellbore damage only, main treatment acid: 15% hcl, skin type: shallow to medium damage, treatment stages: 3 stage preflush, input data: foam injection: shallow-med-deep, 3 stage preflush. fig. 2, real-time operation for acid fracturing, case 2 case-3;well completion: open hole with deep wellbore damage only, main treatment acid: 15% hcl, skin type: shallow to medium damage, treatment stages: 3 stages preflush, input data: no foam, 3 stage preflush shallow-meddeep. fig. 3, real-time operation for acid fracturing, case 3 case-4;well completion: open hole with both of deep wellbore damage only and asphaltene accumulation, main treatment acid: 20% hcl, skin type: shallow to medium damage, evaluation of acid and hydraulic fracturing treatment in halfaya oil field-sadi formation 28 ijcpe vol.18 no.4 (dec. 2017) -available online at: www.iasj.net treatment stages: 3 stages preflush, input data: 3 stage preflush med-deep. fig. 4, real-time operation for acid fracturing, case 4 table 1, comparison in operational results between the four cases after acid fracturing items case 1 case 2 case 3 case 4 initial skin 8.73 8.73 8.73 17.45 final skin -4.33 -6.06 -6.53 -6.84 max. surface pressure. psi 1248 944 944 1725 max. acid fracturing time. min. 741 2801 2801 4061 no. of preflash 3 3 3 3 invasion inch 240 280 400 485 1.1production comparison between the four cases: table 2, comparison the cumulative oil production between the four cases time case 1 case 2 case 3 case 4 days mbbls mbbls mbbls mbbls 365 101.81 101.62 101.75 102.28 730 264.29 262.66 263.20 267.48 1095 414.05 542.06 410.81 564.78 2hydraulic fracturing using pumping rate of 30 gal/min. to reach dimensions fracture conductivity of (fcd = 4.0), three cases have been generated for different fracturing fluids and proppant size and type, these cases can be summarized as follows. case-1 in this case the flowing materials has been used hmp10cp2k as slurry fluid. while, the proppant type was arizona sand 12/200 mesh. the fcd goal was 4.0. fig. (5), shows that the fracture length is increasing with progress of hydraulic fracturing process. and the maximum value reached to about 220 ft after 40.5 minutes of treatment. fig. 5, fracture dimensions jalal abdulwahid al-sudani and khalid munaf husain -available online at: www.iasj.net ijcpe vol.18 no.4 (dec. 2017) 29 case-2 in this case the flowing materials has been used n2 gw27 40 75 as slurry fluid. while, the proppant type was arizona sand 16/30 mesh. the fcd goal was 4.0. fig. (6), shows that the fracture length is increasing with progress of hydraulic fracturing process, and the maximum value reached to about 228 ft after 20 minutes of treatment. fig. 6, fracture dimensions case-3 in this case the flowing materials has been used "spec 2500 1 "as slurry fluid. while, proppant type was arizona sand 16/30. the fcd goal was 4.0. fig. (7), shows that the fracture length is increasing with progress of hydraulic fracturing process, and the maximum value reached to about 223.5 ft after 21.5 minutes of treatment. fig. 7, fracture dimensions hence, fig. (8) shows the dimensions of the fracture and the proppant concentration in 3d view, which can be performed by any of the three cases mentioned above. 2.1 comparison of fracture efficiency between the three cases : table 3, comparison between the three cases in slurry efficiency and proppant average concentration case 1 2 3 fracture slurry efficiency 82 % 78 % 75 % avg. proppant concentration (lb/ft²) 4.74 2.14 2.39 evaluation of acid and hydraulic fracturing treatment in halfaya oil field-sadi formation 30 ijcpe vol.18 no.4 (dec. 2017) -available online at: www.iasj.net fig. 8, fracture width and proppant concentration table 4, production forecast of hydraulic fracturing time days cumulative oil production mbbls oil rate bbl/day cal. bhp psi 0 0 0 4111 10 18.91 1595 1927 20 33.96 1418 1780 30 47.87 1317 1650 51 74.58 1213 1430 91 120.5 1088 1140 120 150.7 970.7 1004 182 207.4 872.3 839.5 228 245.1 799.8 746.7 273 280.3 741 671.9 365 345.1 645.9 541 547 451.3 538 500 730 541.5 455.8 500 1000 654.2 379.2 500 table 5, comparing cumulative production between acid fracturing and hydraulic fracturing treatments time (days) cumulative oil production after acid fracturing mbbls cumulative oil production after hydraulic fracturing mbbls 120 28.662 150.7 365 102.288 451.3 730 267.489 541.5 1000 421.823 654.2 table (5.3),we selected case 4 from acid fracturing treatment to compare with hydraulic fracturing in cumulative oil production after, 120 , 360 ,730 and 1000 days , it can easily be noted that the different is very clear that the preference tend to favor hydraulic fracturing. this evidence prove that hydraulic fracturing treatments gives best results than acid fracturing, for sadi reservoir in halfaya oil field. results and discussion in this section, a detailed discussion for efficiency and production rate resulted from the treatments of acid fracturing and hydraulic fracturing, as follows. 1acid fracturing case 1;fig.(1) shows the events of the stages of acid fracturing process, it can be noted that the bottom hole pressure reaches near the fracturing formation pressure to allow open the effective wormholes, and to achieve the active stimulation process. however, table (1) shows that the skin improvement achieved from (s= 8.73) before the fracturing and reached to (s = 4.33) after fracturing treatment , which is obtained by maximum surface pressure of (1248 psi) .in addition it can be seen that the maximum calculated bottom hole jalal abdulwahid al-sudani and khalid munaf husain -available online at: www.iasj.net ijcpe vol.18 no.4 (dec. 2017) 31 pressure value which approached to the fracture pressure is 5650 psi. while, the pumping rate remained constant at 30 bpm during treatment operation. the viscoelastic divergent fluid used in this treatment allows better spending along the stimulated interval. in this case the hydrocarbon production during the first year, increased from 211 bbl/day to 320 bbl /day. this is about 50% more than the initial production rate. after two years, the production rate rises to reach 100% than the initial production rate. this increment attributed to the affect of removing almost fines deposited by the spent acid, while acidizing process, table (2) shows the hydrocarbon cumulative production for three years. case 2;fig.(2) shows the events of the stages of acid fracturing process, it can be noted that the bottom hole pressure reaches near the fracturing formation pressure to allow open the effective wormholes, and to achieve the active stimulation process. however, table (1) shows that the skin improvement achieved from (s = 8.73) before the fracturing and reached to (s = -6.06) after fracturing treatment , which is obtained by maximum surface pressure of (944 psi). in addition it can be seen that the maximum calculated bottom hole pressure value which approached to the fracture pressure is 4875 psi. while, the pumping rate remained constant at 30 bpm during treatment operation. the viscoelastic divergent fluid used in this treatment allows better spending along the stimulated interval. the hydrocarbon production during the first year, increased from 210 bbl/day to 319 bbl /day. this is about 50% more than the initial production rate. after two years, the production rate rises to reach 100% than the initial production rate. this increment attributed to the affect of removing almost fines deposited by the spent acid, while acidizing process, table (2) shows the hydrocarbon cumulative production for three years. case 3; fig.(3) shows the events of the stages of acid fracturing process, it can be noted that the bottom hole pressure reaches near the fracturing formation pressure to allow open the effective wormholes, and to achieve the active stimulation process. however, table (1) shows that the skin improvement achieved from (s = 8.73) before the fracturing and reached to (s = -6.53) after fracturing treatment, which is obtained by maximum surface pressure of (944 psi). in addition it can be seen that the maximum calculated bottom hole pressure value which approached to the fracture pressure is 4850 psi, while pumping rate remained constant at 30 bpm during treatment operation. the viscoelastic divergent fluid used in this treatment allows better spending along the stimulated interval. the hydrocarbon production during the first year, increased from 210 bbl/day to 320 bbl/day. this is about 50% more than the initial production rate. after two years, the production rate rises to reach 100% than the initial production rate. this increment attributed to the affect of removing almost fines deposited by the spent acid, while acidizing process, table (2) shows the hydrocarbon cumulative production for three years. case 4; fig.(4) shows the events of the stages of acid fracturing process, it can be noted that the bottom hole pressure reaches near the fracturing formation pressure to allow open the effective wormholes, and to achieve the active stimulation process. however, table (1) shows that the skin improvement achieved from (s = evaluation of acid and hydraulic fracturing treatment in halfaya oil field-sadi formation 32 ijcpe vol.18 no.4 (dec. 2017) -available online at: www.iasj.net 17.45) before the fracturing and reached to (s = 6.84) after fracturing treatment, which is obtained by maximum surface pressure of (1725 psi) . in addition it can be seen that the maximum calculated bottom hole pressure value which approached to the fracture pressure is (5525 psi). while, the pumping rate remained constant at 30 bpm during treatment operation. the viscoelastic divergent fluid used in this treatment allows better spending along the stimulated interval. the hydrocarbon production during the first year, increased from 213 bbl/day to 322 bbl/day. this is about 50% more than the initial production rate. after two years, the production rate rises to reach 100% than the initial product ion rate. this increment attributed to the affect of removing almost fines deposited by the spent acid, while acidizing process, table (2) shows the hydrocarbon cumulative production for three years. examining table (2) it can be noted that the results of the four cases, convergent and it can be considered the highest one, which is the case no. 4. the results of case four will be taken to be compared with hydraulic fracture treatment results. 2hydraulic fracturing table (3), through observation of the fracture slurry efficiency values for the three cases, it's very clear that they are convergent and there is no much difference. it seems that a doubling of the proppant concentration made little impact in increasing efficiency, as in case 1 in which the proppant concentration almost double of case 2 and case 3. after hydraulic fracturing treatment completed the production forecast table (4) show that, the average production rates were 150 % of the initial production rate after one year of production. and the average reservoir pressure remained over 2000 psi. while the cumulative hydrocarbon production after 1000 days reached 654.2 mbbls. meanwhile, table (5) shows clear comparison for the cumulative production between acid fracturing treatment and hydraulic fracturing treatment. the hydraulic fracturing gave about five times greater than acid fracturing during the first one year, and more than two times greater for a period of two years of production and reached to one half times greater for a period of three years. conclusions the study shows the comparable success of hydraulic fracturing treatment in low permeability reservoir than fracturing acidizing. however, it also shows that the fracturing acidizing can be used effectively when divergent acid agent may used to provide a good acid dispersion. therefore, these two application needs to be one of a successful jobs that can be adapted in all iraqi fields, that are producing from sadi formation. acknowledgment the authors would like to thanks the software manufacturing company for their assistance in providing a limited license file to perform this study. nomenclature fcd: dimensionless fracture conductivity s: skin factor (dimensionless) jalal abdulwahid al-sudani and khalid munaf husain -available online at: www.iasj.net ijcpe vol.18 no.4 (dec. 2017) 33 references 1frasch,h., “increasing the flow of oil well,” u.s. patent no. 556,669 march 17, 1896 2harris,o.e.,a.r.:"application of acetic acid to well completion stimulation and reconditioning." journal of petroleum technology.637, (1961). 3harris, o. e., a. r. hendrickson, and a. w. coulter:" high concentration acid aids stimulation results in carbonate formations" journal of petroleum technology. (october 1966). 4jurairat densirimongkol., "the role of acidizing in proppant fracturing in carbonate reservoirs", m.sc. texas a&m university (august 2009). 5economides, m.j. and nolte, k.g.: reservoir stimulation, third edition, 750 p. (hardbound) wiley, ny and chichester, (march 2000). 6rajappa, et al. “propped fracture treatments in lower green river formation of the altamont-bluebell field” utah. spe-123526. spe rocky petroleum technology conference, denver-colorado (april, 14-2009) available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.22 no.1 (march 2021) 21 – 27 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: ahmed a. khudhair , email: ahmed.a.khdair@gmail.com, name: ayad a. al-haleem, email: ayadah62@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. treating drill cuttings waste with oil contamination by microwave treatment then by earthworms technique ahmed a. khudhair and ayad a. al-haleem university of baghdad / petroleum engineering dept. abstract in this research paper, two techniques were used to treat the drill cuttings resulting from the oil-based drilling fluid. the drill cuttings were taken from the southern rumaila fields which prepared for testing and fixed with 100 gm per sample and contaminated with two types of crude oil, one from rumaila oilfields with sp.gr of 0.882 and the other from the eastern baghdad oilfield with sp.gr of 0.924 besides contamination levels of 10% and 15% w/w in mass . samples were treated first with microwave with a power applied of 540 & 180 watts as well as a time of 50 minutes. it was found that the results reached below 1% w/w in mass, except for two samples they reached below 1.5% w/w in mass . then, the sample of 1.41% w/w in mass, which has the highest contamination level after microwave treatment, was treated on three groups of earthworms. after the appropriate conditions, samples were prepared for treating by earthworms and for an incubation period of 21 days, the results highlighted the effectiveness of the succession process by reaching concentrations below 0.92%, 0.65%, and 0.42% w/w in mass. keywords: drill cuttings waste, microwave treatment, oil contamination, earthworms treatment received on 02/07/2020, accepted on 15/12/2020, published on 30/03/2021 https://doi.org/10.31699/ijcpe.2021.1.3 1introduction waste disposal operations from the oil and gas industry, unexpected accident leakage, or improperly disposing of drilling waste, have quite serious consequences for human health and the environment in general. when contaminated drill cuttings are removed with the remaining drilling fluids, especially with oil-based mud (obm), the chemical fractions of liquids begin to seep into the ground, causing the elimination of existing organisms and contaminated groundwater [1]. normally, the remains of the drilling mud (whether it was oil-based mud or water-based mud) and the drill cuttings are associated with the presence of various hydrocarbon concentrations and heavy materials. the saturated and unsaturated hydrocarbon concentrations are greater in the oil-based mud, these concentrations can reach about 50% and this percentage is more than that in water-based mud (wbm). accordingly, it is more toxic than wbm [2]. since the disposal of drilling waste had become a global problem that causes escalating anxiety, especially for researchers and oil companies, due to the multiple negative impacts on public and environmental health [3], oil and gas wells drilling in iraq cannot be an exception in this manner. drilling waste produced by the exploration and production industry is coming in the second place of international ranking for the largest volume of waste produced [4]. the waste disposal problem has become an important point in achieving a good environmental management system. in general, contamination of drilling fluids with drill cuttings waste is an inevitable result of successful drilling operations; therefore, drill cuttings waste accumulation ought to go through the treatment and disposal option after all. in that situation of the drill cuttings that need to be handled earlier to disposal, there are numerous feasible selections including land-farming, bioremediation, solidification, thermal desorption, stabilization, and cuttings re-injection [5], etc. land reclamation is a regularly utilized bioremediation strategy in which the oil-contaminated drill cuttings are applied to the land where evaporation synchronically with the natural organisms of the soil combines to diminish the pollution of the waste [6], [7]. among these ways, bioremediation can be considered as a well-proven and environmentally acceptable technology that employs microorganisms (i.e. bacteria, fungi, and or earthworms) to biologically eliminate oil contaminated waste into nontoxic remnant and reduce contaminant concentrations to acceptable levels. vermiculture or worms farming is a well-steady technique for remediating organic wastes and decompose them into a material eligible for receiving essential nutrients to increase flora growth [8]. earthworms are an important indicator of soil health, as their presence means the quality of the soil and its absence means the opposite [9], [10]. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:ahmed.a.khdair@gmail.com mailto:ayadah62@yahoo.com http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2021.1.3 a. a. khudhair and a. a. al-haleem / iraqi journal of chemical and petroleum engineering 22,1 (2021) 21 27 22 earthworms are also a good predictor of toxicity measurement and have been used to assess environmental risks [11][12] [13]. however, scientific information remains limited about the sensitivity of earthworms to contaminated soil, as well as their viability and mechanism of treating the soil [14][12]. several important studies have highlighted the activity of earthworm use to promote hydrocarbon contaminant loss from soil [15][16]. on the other hand, microwave drying is one of the modern technologies used industrially and at home, which showed effective results in its practical applications and brought about an ever-increasing change with drying various materials [17] [18]. the treatment levels accomplished by the microwave drying process were significantly greater than those used in the solid control system [19] [20]. the microwave technique is a treatment method for handling waste of many kinds and has multiple advantages. it is also easy to use and fast to accomplish, as well as it can be controlled remotely and with great flexibility. furthermore, the microwave can reach the required temperature in less than 1% of the time required by traditional heating methods. besides, the microwave technique is preferred as it considered to be a source of clean energy [21] [22] [23] the application of a microwave oven, which can be used on-site, is one of the high gain methods in terms of the process of greatly reducing pollution levels that meet the legal requirements for treating and storing waste, unlike the usual methods whose results are almost satisfactory. however, a successful microwave treatment requires a lot of knowledge or experience to understand the effect of uneven heating of constituent or thermal leakage. the other side of the disadvantages of this treatment is the need for electrical energy, which is one of the most expensive forms of energy, as the microwave oven requires energy with a thin layer to apply waste penetration [24] [25]. the approach used in this study tries to reach close to zero discharge concept of oil contamination in waste solids, a combination of microwave treatment and earthworm technique will be discussed. 2experimental work 2.1. fundamental materials a. drill cuttings the drill cuttings, which have been used in this study, were collected from south al-rumaila oilfield pits as shows in fig. 1. the waste drill cuttings obtained from the al-rumaila waste pit were the result of the formation which has been drilled and the remaining separating water-based mud. as a result, the drill cuttings are needed to be prepared before the treatment. therefore, the drill cuttings had been treated in a microwave oven by applying maximum power applied for 24 hours to get rid of the water and organic contents. then, pure samples were taken from the drill cuttings and fixed at (100 gm weight) and crushed to have a size of grain (5-10 mm) for each sample as shown in fig. 2. fig. 1. drill cutting of south al-rumaila oilfield pits fig. 2. weight of prepared sample of drill cuttings b. hydrocarbon specification two types of hydrocarbon were taken. the first type of crude oil was taken from the reservoir of south alrumaila oilfield in basra before it goes to clarify impurities and the other one was taken from eastern baghdad oilfield in baghdad after the treatment from the impurities. the hydrocarbon’s specific gravity of the south alrumaila oilfield was measured (sp.gr=0.882). whereas the hydrocarbon’s specific gravity of eastern of baghdad oilfield was (sp.gr=0.924). c. microwave device the specifications of the microwave device were of model no. of gmo-330; inputs of 50 hz and 1400-watt; the output of 2450 hz, maximum of 900 watt and selective power applied and grill of 1100 watt as shown in fig. 3. a. a. khudhair and a. a. al-haleem / iraqi journal of chemical and petroleum engineering 22,1 (2021) 21 27 23 fig. 3. microwave device used in this study d. earthworms selection an earthworm called “allolobophora” was used for treatment. the selected earthworms are allolobophora, have the following bio classification: phylum: annelida, class: oligochaeta, order: opisthopora [26]. the average weight of these earthworms is (2.2gm) and their average length is (3 cm). 2.2. experimental set-up a. microwave treatment three parameters were taken; the power applied was (180 and 540 watt), the hydrocarbon concertation was (10%, and 15% w/w in mass) for two kinds of hydrocarbon as mentioned before with specific gravity (0.882 and 0.924). the period of treatment was (50 min) dividing by four times which is (10, 20, 30, and 50 min). b. earthworms treatment after the microwave treatment was finished, it was noticed that only one sample was (1.41% w/w in mass) and the others below or about 1% of contamination. as a result, the parameters were taken according to that to reduce the pollution (1% w/w in mass) or less. three groups of earthworms were taken (5, 10, and 15 in counts). the duration of the experiment was 21 days divided into 3 weeks, and the treated hydrocarbon concentrations were examined at the end of each week. the treated drill cuttings, with 1.41% w/w in mass were prepared by adding (50% w/w in mass) of fertile soil that came from the same source of the obtained earthworms. neutron food (carrots, cabbage, and waste of slaughterhouse) was added by (20% w/w in mass) to the total weight, taking into account the addition of fertilizer as a ratio (25:1) of nitrogen to phosphor to each sample [26] as is shown in fig. 4. fig. 4. earthworms treatment sample 3analytical method 3.1. microwave analysis the process of analyses to monitor the progress in decreasing the oil contamination was checked using the electronic balance instrument. at first, a glass container weight was calculated for each sample. then, the polluted drill cuttings were weighted and since the drill cuttings weight is fixed at 100 gm, the formula that represented the remain of hydrocarbon concentration is as follow: w𝑛 = w𝑡(𝑛) − (wℎ𝑦𝑑𝑖 + w𝑐𝑜𝑛 + w𝑐𝑢𝑡) (1) where: wn= the remaining weight of hydrocarbon after any time in gm unit. wℎ𝑦𝑑𝑖= the initial weight of hydrocarbon before treatment in gm unit . w𝑐𝑜𝑛 = weight of glass container in gm unit. w𝑐𝑢𝑡= weight of fixed drill cuttings which is 100 gm. w𝑡(𝑛)= the total weight at any period of hydrocarbon contamination, drill cuttings of 100 gm, and their container in gm unit. 3.2. earthworm analysis the process of analyzes was done by taking (1 or 3 gm) of the sample, considering it represented the entire sample, and it is added to a tube containing (3 or 9 ml) of a solvent called n-hexane. after that, the vertex device performed a shaking and mixing process for three minutes in preparation for the centrifuge device so that the hydrocarbons are separated from the solvent and the drill cuttings well using the principle of different densities. one milliliter of hydrocarbons is taken and injected into the gaschromatography device to maintain the results. a. a. khudhair and a. a. al-haleem / iraqi journal of chemical and petroleum engineering 22,1 (2021) 21 27 24 4results and discussions 4.1. microwave treatment results and discussion it appears from table 1 and table 2 the concentrations decreased with the increase of time. table 1. treating drill cutting with power applied 180 watt time in min. concentration of sp. gr. 0.882 concentration of sp. gr. 0.882 concentration of sp. gr. 0.924 concentration of sp. gr. 0.924 0 10% 15% 10% 15% 10 9.12% 14.79% 9.21% 14.83% 20 7.25% 13.5% 7.01% 13.62% 30 1.78% 10.71% 1.47% 9.23% 50 0.62% 1.41% 0.49% 1.01% table 2. treating drill cutting with power applied 540 watt time in min. concentration of sp. gr. 0.882 concentration of sp. gr. 0.882 concentration of sp. gr. 0.924 concentration of sp. gr. 0.924 0 10% 15% 10% 15% 10 8.79% 14.55% 8.13% 14.68% 20 1.57% 11.58% 1.34% 11.07% 30 1.02% 7.32% 0.94% 7.19% 50 0.47% 0.91% 0.41% 0.83% tables above show that the relationship between time and the decrease of concentrations is a direct correlation. in general, as shown in fig. 5 and fig. 6 below when the power applied is increased the contamination dropping increases in which fluid reduction increased and drying time was shortened by raising microwave power in which microwave ovens can transfer energy to the entire substance, as the energy affects the internal structure. this will cause higher energy acting on the internal structure when the power applied increased [27]. moreover, when the concentration of the hydrocarbon in drill cuttings is less, the treatment reaches less than 1% much faster. furthermore, microwave penetration faces difficulties when the concentration of oil contamination in drill cutting increases. for that reason, for concentration (10% w/w in mass) in the first ten minutes, the decreasing in contamination is not like the concentration in (15% w/w in mass) when the thickness of sludge layer of the sample inside microwave chamber increased the penetration of microwave takes longer time to achieve the drying process [27], [29]. despite increasing the power applied in the microwave treatment to increase the speed of reducing hydrocarbon concentrations can only be useful till about 35-40 minutes as it shows that from 35-40 minutes till fifty minute the decrease in oil contamination is relatively slow. the study attributes the relatively slowly in decreasing of concentration in the last fifteen minutes to the residue of high-density compositions ’in which the microwave has difficulty in treating them’ that remain after the evaporating of the light compositions. besides that the range of specific gravities which is taken, shows the regular type of crude oil obtained from iraqi oil fields and that will lead to a conclusion which is the difference in specific gravities does not affect directly the concentration decreasing when the microwave is used for treating a drill cutting with oil contamination (obtained from iraqi reservoir). fig. 5. oil contamination reduction of 10% w/w in mass with time fig. 6. oil contamination reduction of 15% w/w in mass with time 4.2. earthworms treatments results and discussion table 3 shows the reduction in contamination of hydrocarbon when time is passing through. table 3. earthworm’s treatment on the treated oil of 0.882 sp. gr time in days concentration with 5 earthworms in w/w in mass concentration with 10 earthworms in w/w in mass concentration with 15 earthworms in w/w in mass 0 1.41% 1.41% 1.41% 7 1.23% 1.08% 0.91% 14 1.06% 0.86% 0.61% 21 0.92% 0.65% 0.42% when the earthworm’s numbers increase the treatment of the polluted drill cuttings increased [26]. it appears that the concentrations decreased after 21 days. also, it reveals that the decreasing increase with the time increment. a. a. khudhair and a. a. al-haleem / iraqi journal of chemical and petroleum engineering 22,1 (2021) 21 27 25 the treatment showed great effect and this indicates that treatment with earthworms after microwave treatment recorded success. in general, reaching such results not even reached below the international regulation but for many countries reached better than the target of environmental treating as for us environmental protection agency (us epa) stated that discharged cuttings cannot be greater than (6.9% by mass) for the organic pollution of synthetic fluid adhered. besides, in the united kingdom and european union, the discharge regulation compliance obliges a limit of less than 5.5% of organic content and 1% of oil on cuttings [1], [30]. 5conclusion the application of the two techniques together leads to the possibility of reducing the power applied by the microwave as well as reducing the range of time in its work, which reduces the consumption side of electrical energy. the same applies to biological treatment by earthworms in terms of numbers and days of monitoring. less than 1% w/w in a mass of oil pollution can be reached from 15% w/w in mass and may approach zero discharge with increasing the incubation period of earthworms treatments. reference [1] siddique, s., kwoffie, l., addae-afoakwa, k., yates, k., & njuguna, j. (2017, may). oil based drilling fluid waste: an overview on environmentally persistent pollutants. in iop conference series: materials science and engineering (vol. 195, no. 1, p. 012008). iop publishing. [2] darley, henry ch, and george r. gray. composition and properties of drilling and completion fluids. gulf professional publishing, 1988. [3] moseley hr (1983) summary of api onshore drilling and produced water environmental studies. spe.11398 presented at iadc/spe drilling conf. new orleans. [4] haut, r. c., rogers, j. d., mcdole, b. w., burnett, d., & olatubi, o. (2007, april). minimizing waste during drilling operations. in 2007 aade national technical conference and exhibition, houston. [5] growcock, f. b., curtis, g. w., hoxha, b., brooks, w. s., & candler, j. e. (2002, january). designing invert drilling fluids to yield environmentally friendly drilled cuttings. in iadc/spe drilling conference. society of petroleum engineers. [6] zimmerman, p. k., & robert, j. d. (1991). oilbased drill cuttings treated by landfarming. oil and gas journal;(united states), 89(32). [7] chaineau, c. h., morel, j. l., & oudot, j. (1996). land treatment of oil-based drill cuttings in an agricultural soil. journal of environmental quality, 25(4), 858-867 [8] getliff, j., mcewan, g., ross, s., richards, r., & norman, m. (2002, april). drilling fluid design and the use of vermiculture for the remediation of drill cuttings. in the aade 2002 technology conference “drilling & completion fluids and waste management”, houston, texas. -2002. [9] doube bm, schmidt o (1997). can the abundance or activity of soil macrofauna be used to indicate the biological health of soils? in: biological indicators of soil health. eds. c. pankhurst, b doube and v. gupta. cab international new york. pp. 265-295 [10] edwards wm, shipitalo mj (1998). consequences of earthworms in agricultural soils; aggregation and porosity. in earthworm ecology (eds c.a. edwards) st. lucie press boca raton, florida. pp. 147161. [11] dorn, p. b., & salanitro, j. p. (2000). temporal ecological assessment of oil contaminated soils before and after bioremediation. chemosphere, 40(4), 419-426. [12] salanitro, j. p., dorn, p. b., huesemann, m. h., moore, k. o., rhodes, i. a., rice jackson, l. m., ... & wisniewski, h. l. (1997). crude oil hydrocarbon bioremediation and soil ecotoxicity assessment. environmental science & technology, 31(6), 1769-1776. [13] eijsackers, h. j. p. (1998). soil quality assessment in an international perspective: generic and landuse based quality standards. ambio: a journal of the human environment, 27, 70-77. [14] neuhauser, d., & baer, m. (1989). the application of wave packets to reactive atom–diatom systems: a new approach. the journal of chemical physics, 91(8), 4651-4657. [15] ma,w.c.,immerzeel,j. and bodt,j.(1995). earthworm and food interactions on bioaccumulation and disappearance in soil of polycyclic aromatic hydrocarbons: studies on phenanthrene and fluoranthene.ecotoxicology and environmental safety.32:226-32. [16] schaefer,m.and filser j .(2007).the influence of earthworms and organic additives on the biodegradation of oil-contaminatedsoil.applied soil ecology.36:53-62. [17] vickers, n. j. (2017). animal communication: when i’m calling you, will you answer too? current biology, 27(14), r713-r715. [18] omran, m., fabritius, t., elmahdy, a. m., abdelkhalek, n. a., el-aref, m., & elmanawi, a. e. h. (2014). effect of microwave pre-treatment on the magnetic properties of iron ore and its implications on magnetic separation. separation and purification technology, 136, 223-232. [19] robinson, j. p., kingman, s. w., snape, c. e., barranco, r., shang, h., bradley, m. s. a., & bradshaw, s. m. (2009). remediation of oilcontaminated drill cuttings using continuous microwave heating. chemical engineering journal, 152(2-3), 458-463. https://iopscience.iop.org/article/10.1088/1757-899x/195/1/012008/meta https://iopscience.iop.org/article/10.1088/1757-899x/195/1/012008/meta https://iopscience.iop.org/article/10.1088/1757-899x/195/1/012008/meta https://iopscience.iop.org/article/10.1088/1757-899x/195/1/012008/meta https://iopscience.iop.org/article/10.1088/1757-899x/195/1/012008/meta https://iopscience.iop.org/article/10.1088/1757-899x/195/1/012008/meta https://iopscience.iop.org/article/10.1088/1757-899x/195/1/012008/meta https://books.google.iq/books?hl=en&lr=&id=qn52v8jllmic&oi=fnd&pg=pp10&dq=composition+and+properties+of+drilling+and+completion+fluids&ots=ax8xdcue9t&sig=w_tkdkmyn7n87t93yhmusppfduc&redir_esc=y#v=onepage&q=composition%20and%20properties%20of%20drilling%20and%20completion%20fluids&f=false https://books.google.iq/books?hl=en&lr=&id=qn52v8jllmic&oi=fnd&pg=pp10&dq=composition+and+properties+of+drilling+and+completion+fluids&ots=ax8xdcue9t&sig=w_tkdkmyn7n87t93yhmusppfduc&redir_esc=y#v=onepage&q=composition%20and%20properties%20of%20drilling%20and%20completion%20fluids&f=false https://books.google.iq/books?hl=en&lr=&id=qn52v8jllmic&oi=fnd&pg=pp10&dq=composition+and+properties+of+drilling+and+completion+fluids&ots=ax8xdcue9t&sig=w_tkdkmyn7n87t93yhmusppfduc&redir_esc=y#v=onepage&q=composition%20and%20properties%20of%20drilling%20and%20completion%20fluids&f=false https://books.google.iq/books?hl=en&lr=&id=qn52v8jllmic&oi=fnd&pg=pp10&dq=composition+and+properties+of+drilling+and+completion+fluids&ots=ax8xdcue9t&sig=w_tkdkmyn7n87t93yhmusppfduc&redir_esc=y#v=onepage&q=composition%20and%20properties%20of%20drilling%20and%20completion%20fluids&f=false https://onepetro.org/spedc/proceedings-abstract/83dc/all-83dc/spe-11398-ms/61293 https://onepetro.org/spedc/proceedings-abstract/83dc/all-83dc/spe-11398-ms/61293 https://onepetro.org/spedc/proceedings-abstract/83dc/all-83dc/spe-11398-ms/61293 https://onepetro.org/spedc/proceedings-abstract/83dc/all-83dc/spe-11398-ms/61293 https://onepetro.org/spedc/proceedings-abstract/02dc/all-02dc/spe-74474-ms/136896 https://onepetro.org/spedc/proceedings-abstract/02dc/all-02dc/spe-74474-ms/136896 https://onepetro.org/spedc/proceedings-abstract/02dc/all-02dc/spe-74474-ms/136896 https://onepetro.org/spedc/proceedings-abstract/02dc/all-02dc/spe-74474-ms/136896 https://onepetro.org/spedc/proceedings-abstract/02dc/all-02dc/spe-74474-ms/136896 https://www.cabdirect.org/cabdirect/abstract/19971907221 https://www.cabdirect.org/cabdirect/abstract/19971907221 https://www.cabdirect.org/cabdirect/abstract/19971907221 https://www.cabdirect.org/cabdirect/abstract/19971907221 https://www.cabdirect.org/cabdirect/abstract/19971907221 https://www.cabdirect.org/cabdirect/abstract/19971907221 https://ci.nii.ac.jp/naid/10013244568/ https://ci.nii.ac.jp/naid/10013244568/ https://ci.nii.ac.jp/naid/10013244568/ https://ci.nii.ac.jp/naid/10013244568/ https://ci.nii.ac.jp/naid/10013244568/ https://www.sciencedirect.com/science/article/abs/pii/s0045653599003045 https://www.sciencedirect.com/science/article/abs/pii/s0045653599003045 https://www.sciencedirect.com/science/article/abs/pii/s0045653599003045 https://www.sciencedirect.com/science/article/abs/pii/s0045653599003045 https://pubs.acs.org/doi/abs/10.1021/es960793i https://pubs.acs.org/doi/abs/10.1021/es960793i https://pubs.acs.org/doi/abs/10.1021/es960793i https://pubs.acs.org/doi/abs/10.1021/es960793i https://pubs.acs.org/doi/abs/10.1021/es960793i https://pubs.acs.org/doi/abs/10.1021/es960793i https://www.narcis.nl/publication/recordid/oai:research.vu.nl:publications%2f7f66c6a1-1764-415e-bf01-8094637f4492 https://www.narcis.nl/publication/recordid/oai:research.vu.nl:publications%2f7f66c6a1-1764-415e-bf01-8094637f4492 https://www.narcis.nl/publication/recordid/oai:research.vu.nl:publications%2f7f66c6a1-1764-415e-bf01-8094637f4492 https://www.narcis.nl/publication/recordid/oai:research.vu.nl:publications%2f7f66c6a1-1764-415e-bf01-8094637f4492 https://aip.scitation.org/doi/abs/10.1063/1.456755 https://aip.scitation.org/doi/abs/10.1063/1.456755 https://aip.scitation.org/doi/abs/10.1063/1.456755 https://aip.scitation.org/doi/abs/10.1063/1.456755 https://www.sciencedirect.com/science/article/abs/pii/s0147651385711086 https://www.sciencedirect.com/science/article/abs/pii/s0147651385711086 https://www.sciencedirect.com/science/article/abs/pii/s0147651385711086 https://www.sciencedirect.com/science/article/abs/pii/s0147651385711086 https://www.sciencedirect.com/science/article/abs/pii/s0147651385711086 https://www.sciencedirect.com/science/article/abs/pii/s0147651385711086 https://www.sciencedirect.com/science/article/abs/pii/s092913930600240x https://www.sciencedirect.com/science/article/abs/pii/s092913930600240x https://www.sciencedirect.com/science/article/abs/pii/s092913930600240x https://www.sciencedirect.com/science/article/abs/pii/s092913930600240x https://www.sciencedirect.com/science/article/pii/s0960982217306309 https://www.sciencedirect.com/science/article/pii/s0960982217306309 https://www.sciencedirect.com/science/article/pii/s0960982217306309 https://www.sciencedirect.com/science/article/abs/pii/s138358661400567x https://www.sciencedirect.com/science/article/abs/pii/s138358661400567x https://www.sciencedirect.com/science/article/abs/pii/s138358661400567x https://www.sciencedirect.com/science/article/abs/pii/s138358661400567x https://www.sciencedirect.com/science/article/abs/pii/s138358661400567x https://www.sciencedirect.com/science/article/abs/pii/s138358661400567x https://www.sciencedirect.com/science/article/abs/pii/s1385894709003593 https://www.sciencedirect.com/science/article/abs/pii/s1385894709003593 https://www.sciencedirect.com/science/article/abs/pii/s1385894709003593 https://www.sciencedirect.com/science/article/abs/pii/s1385894709003593 https://www.sciencedirect.com/science/article/abs/pii/s1385894709003593 https://www.sciencedirect.com/science/article/abs/pii/s1385894709003593 a. a. khudhair and a. a. al-haleem / iraqi journal of chemical and petroleum engineering 22,1 (2021) 21 27 26 [20] robinson, j. p., kingman, s. w., snape, c. e., bradshaw, s. m., bradley, m. s. a., shang, h., & barranco, r. (2010). scale-up and design of a continuous microwave treatment system for the processing of oil-contaminated drill cuttings. chemical engineering research and design, 88(2), 146-154. [21] haghi, a.k., & amanifard, n. (2008). analysis of heat and mass transfer during microwave drying of food products,brazilian journal of chemical engineering, 25, 491–501. [22] fernandez, y., arenillas, a., & menendez, j.a. (2011). microwave heating applied to pyrolysis. in s. grundas (ed.), advances in induction and microwave heating of mineral and organic materials. (pp. 723–751), london, uk: intechopen. [23] fernandez-luqueno, f., valenzuela-encinas, c., marsch, r., martínez-suarez, c., vazquezn unez, e., dendooven, l., 2011. microbial communities to mitigate contamination of pahs in soil e possibilities and challenges: a review. environmental science and pollution research 18 (1), 12e30. [24] regier, m., & schubert, h. (2001). microwave processing. in p. richardson (ed.), thermal technologies in food processing. (pp. 178–207), germany: woodhead publishing ltd. [25] proestos, c., & komaitis, m. (2008). application of microwave-assisted extraction to the fast extraction of plant phenolic compounds, lwtfood science and technology, 41, 652–659. [26] al-haleem, a. a., & abed, k. m. (2016). treating of oil-based drill cuttings by earthworms. research journal of pharmaceutical biological and chemical sciences, 7(6), 2088-2094. [27] tinmaz köse, e., çelen, s., & çelik, s. ö. (2019). conventional and microwave drying of hydrocarbon cutting sludge. environmental progress & sustainable energy, 38(4), 13104. [28] silva mota, a. c., santos, j. m., silva rossi, a., duarte, c. r., pereira, m. s., & ataíde, c. h. (2019). dielectric properties and microwave drying kinetics of drill cuttings contaminated with synthetic drilling fluid. drying technology, 38(7), 940-951. [29] junior, i. p., pereira, m. s., dos santos, j. m., duarte, c. r., ataíde, c. h., & panisset, c. m. d. á. (2015). microwave remediation of oil well drill cuttings. journal of petroleum science and engineering, 134, 23-29. [30] santos, j. m., petri, i. j., mota, a. c. s., dos santos morais, a., & ataíde, c. h. (2018). optimization of the batch decontamination process of drill cuttings by microwave heating. journal of petroleum science and engineering, 163, 349-358. https://www.sciencedirect.com/science/article/abs/pii/s0263876209001841 https://www.sciencedirect.com/science/article/abs/pii/s0263876209001841 https://www.sciencedirect.com/science/article/abs/pii/s0263876209001841 https://www.sciencedirect.com/science/article/abs/pii/s0263876209001841 https://www.sciencedirect.com/science/article/abs/pii/s0263876209001841 https://www.sciencedirect.com/science/article/abs/pii/s0263876209001841 https://www.sciencedirect.com/science/article/abs/pii/s0263876209001841 %5b21%5d%09haghi,%20a.k.,%20&%20amanifard,%20n.%20(2008).%20analysis%20of%20heat%20and%20mass%20transfer%20during%20microwave%20drying%20of%20food%20products,brazilian%20journal%20of%20chemical%20engineering,%2025,%20491–501. %5b21%5d%09haghi,%20a.k.,%20&%20amanifard,%20n.%20(2008).%20analysis%20of%20heat%20and%20mass%20transfer%20during%20microwave%20drying%20of%20food%20products,brazilian%20journal%20of%20chemical%20engineering,%2025,%20491–501. %5b21%5d%09haghi,%20a.k.,%20&%20amanifard,%20n.%20(2008).%20analysis%20of%20heat%20and%20mass%20transfer%20during%20microwave%20drying%20of%20food%20products,brazilian%20journal%20of%20chemical%20engineering,%2025,%20491–501. %5b21%5d%09haghi,%20a.k.,%20&%20amanifard,%20n.%20(2008).%20analysis%20of%20heat%20and%20mass%20transfer%20during%20microwave%20drying%20of%20food%20products,brazilian%20journal%20of%20chemical%20engineering,%2025,%20491–501. https://digital.csic.es/handle/10261/32630 https://digital.csic.es/handle/10261/32630 https://digital.csic.es/handle/10261/32630 https://digital.csic.es/handle/10261/32630 https://digital.csic.es/handle/10261/32630 https://link.springer.com/article/10.1007/s11356-010-0371-6 https://link.springer.com/article/10.1007/s11356-010-0371-6 https://link.springer.com/article/10.1007/s11356-010-0371-6 https://link.springer.com/article/10.1007/s11356-010-0371-6 https://link.springer.com/article/10.1007/s11356-010-0371-6 https://link.springer.com/article/10.1007/s11356-010-0371-6 https://link.springer.com/article/10.1007/s11356-010-0371-6 https://www.sciencedirect.com/science/article/abs/pii/s0023643807001788 https://www.sciencedirect.com/science/article/abs/pii/s0023643807001788 https://www.sciencedirect.com/science/article/abs/pii/s0023643807001788 https://www.sciencedirect.com/science/article/abs/pii/s0023643807001788 https://aiche.onlinelibrary.wiley.com/doi/abs/10.1002/ep.13104 https://aiche.onlinelibrary.wiley.com/doi/abs/10.1002/ep.13104 https://aiche.onlinelibrary.wiley.com/doi/abs/10.1002/ep.13104 https://aiche.onlinelibrary.wiley.com/doi/abs/10.1002/ep.13104 https://www.tandfonline.com/doi/abs/10.1080/07373937.2019.1625362 https://www.tandfonline.com/doi/abs/10.1080/07373937.2019.1625362 https://www.tandfonline.com/doi/abs/10.1080/07373937.2019.1625362 https://www.tandfonline.com/doi/abs/10.1080/07373937.2019.1625362 https://www.tandfonline.com/doi/abs/10.1080/07373937.2019.1625362 https://www.sciencedirect.com/science/article/abs/pii/s0920410515300681 https://www.sciencedirect.com/science/article/abs/pii/s0920410515300681 https://www.sciencedirect.com/science/article/abs/pii/s0920410515300681 https://www.sciencedirect.com/science/article/abs/pii/s0920410515300681 https://www.sciencedirect.com/science/article/abs/pii/s0920410515300681 https://www.sciencedirect.com/science/article/abs/pii/s0920410518300032 https://www.sciencedirect.com/science/article/abs/pii/s0920410518300032 https://www.sciencedirect.com/science/article/abs/pii/s0920410518300032 https://www.sciencedirect.com/science/article/abs/pii/s0920410518300032 https://www.sciencedirect.com/science/article/abs/pii/s0920410518300032 a. a. khudhair and a. a. al-haleem / iraqi journal of chemical and petroleum engineering 22,1 (2021) 21 27 27 الصخري ذو التلوث النفطي بواسطة جهاز المايكروويف ومن ثم معالجة مخلفات الفتات بتقنية ديدان األرض احمد امين خضير و اياد عبد الحليم هندسة النفطقسم –كلية الهندسة -جامعة بغداد الخالصة جراء تم استخدام طريقتين بالتتابع لمعالجة الفتات الصخري الملوث نفطيا من اجل إيجاد حل لمشاكل التلوث الحفر بسائل الحفر ذو األساس النفطي. حيث ُأخذت عينات الفتات الصخري من حقول الرميلة الجنوبي وتم غم ألغراض التجربة، واخذت عينتان من النفط أحدهما من 100تحضير العينات وتثبيت وزن كل عينة بـ . أيضا تم 0.924بكثافة نوعية واألخرى من حقل شرقي بغداد 0.882حقول الرميلة الجنوبي بكثافة نوعية % من التلويث النفطي بنوعيه. وكانت نتائج تجربة المايكروويف الذي 15% و10تلويث الفتات الصخري بنسب % 1واط ناجحة حيث وصلت نسبة التلوث النفطي الى ما دون الـ 180و 540تم استخدام قوة مسلطة فيه دقيقة لكل عينة. بعدها تم اخذ اعلى تركيز لعينة 50دة قدرها % بم1.5لجميع العينات عدا عينتان ما دون الـ وتحضيرها لفحص مدى قدرة ديدان األرض على معالجة 14100تمت معالجتها من قبل المايكروويف بمقدار وكانت نتائج 15و 10و 5يوم لثالث مجاميع من ديدان األرض 21التلوث المتبقي وكانت مدة الحضانة % منذ التلوث البدائي مما يدل إمكانية معالجة مشكلة التلوث النفطي 0,05الى ما دون ال التلوث قد انخفضت عند استخدام سائل الحفر ذو األساس النفطي وما يشاكله. الكلمات الدالة: الفتات الصخري، معالجة بالمايكرويف، معالجة بديدان األرض، التلوث النفطي. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.21 no.3 (september 2020) 1 – 8 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: sahmi eddwan mohammed, email: engpetro.king@gmail.com, name: faleh h. m. almahdawi, email: fhnetr@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. experimental study for assessment of cutting density effect on hole cleaning efficiency in inclined and horizontal wells sahmi eddwan mohammed and faleh h. m. almahdawi university of baghdad, petroleum engineering department abstract the poor hole cleaning efficiency could causes many problems such as high torque, drag, poor hydraulics and pipe stuck. these inherent problems result in an avoidable high operation cost which this study tried to address. in this study, the effect of cutting density on hole cleaning efficiency in deviated and horizontal wells was investigated. experiments were conducted using 40 feet (12 m) long of flow loop made from iron and pvc. however, the test section was made from pvc with (5.1m) long and (4” id) for outer pipe and (2” od) inner pipe. the cutting transport ratio (ctr) was determined from weight measurements for each test. cutting transport ratio has been investigated for effects of the following parameters; flow rate, cutting size and density, yield point of drilling mud, and inclination angle. once the setup was positioned at the desired inclination, the cutting was transported for 3 minutes at a constant flow rate and yield point. the amount of cutting removed during each test was thereafter weighted to determine cutting transport ratio ctr. the results obtained from this study showed that the cutting density has a slight to moderate effect on hole cleaning efficiency. also, there was a remarkable improvement in the cutting transport ratio annular velocity and hole inclination angle was increased. however, the yield point (yp) was negligible at maximum values of annular velocity. therefore, at high value of yield point the cuttings with large and medium size were transported more than small size. this case is inversed at a low value of yp. moreover, for all sizes the heavy cutting transport less than light cutting. finally, the critical angle was recorded between 65 o -75 o . sigma plot 12.5 program has been used to graph all figures in this paper. keywords: cutting transport ratio, particle density, hole cleaning efficiency, yield point received on 12/01/2020, accepted on 31/05/2020, published on 30/09/2020 https://doi.org/10.31699/ijcpe.2020.3.1 1introduction directional and horizontal wells have proven to be successful field development methods in order to meet the demand for a higher rate of returns and increased recovery factor. increase in the number of such wells being completed has led to a growth in the frequency of hole-cleaning procedures being conducted in the oilfield. wellbore cleanout is often performed to remove solid particles such as post-fracturing residual proppant, milled plug debris or produced sand [1]. the complexity of this process is governed by independent factors (flow rate, and fluid and solid properties) as well as the interaction between each of these factors. the available research comprises of many empirical correlations and some rules-of-thumb (such as to circulate 2-3 times the annular volume) to achieve efficient cleaning [2,3,4]. most often, these correlations are specific to certain configurations and cannot be applied universally. the effect of such factors affecting wellbore cleanout mechanism has been widely studied previously. multifactor interactions between these parameters further govern the efficiency of cuttings removal. many studies have concluded that the fluid flow rate or flow velocity has the most significant and direct impact on solids removal. similarly, a higher density of the fluids has a positive impact on hole cleaning by reducing the effective weight of the solid particle. additionally, research on the influence of fluid rheology is another common theme amongst several studies. these parameters are studied widely majorly due to the reason that they are easily controllable in field cleanout operations. however, certain parameters, especially cutting density, cannot be controlled in the field and hence, it is neglected in most of the studies related to hole-cleaning. a dense particle can settle from suspension into a stationary bed relatively easily, making it difficult to remove from the wellbore. although the density of the solid particles to be removed from the wellbore cannot be modified, the cleanout process can be designed to account for the predicted solids density. specifically to the drilling process, the increase in cuttings density can result in a substantial increase in equivalent circulating density (ecd) of the mud system. an unexpected and unpredicted increase in ecd can cause severe problems such as unwanted fractures in the formation and subsequent loss of mud. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:engpetro.king@gmail.com mailto:fhnetr@yahoo.com http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2020.3.1 s. e. mohammed and f. h. m. almahdawi / iraqi journal of chemical and petroleum engineering 21,3 (2020) 1 8 2 this results in severe damage to the formation and significantly reduces hydrocarbon production. hence, it is imperative to study the magnitude and effect density of cuttings in addition to other controllable parameters to optimize cleanout efficiency [5,6,7,8]. furthermore, for a laminar flow, the effect of particle density on the hole cleaning mechanism in vertical section can be predicted using simplified physical relationships. from past research, a number of experimental investigations were conducted to study the factors affecting the removal of drilled cuttings in vertical wells; cuttings density being one of them. nguyen and rahman borrowed this definition and conducted a study that involved summarizing the effect of cuttings density of uniform bed thickness as a part of it. simulations conducted involved use of two cuttings type having specific gravity values of 2.62 and 1.7. according to a mechanistic model nguyen and rahman, a decrease in cuttings density is expected to reduce significantly normalized bed height. moreover, the minimum transport velocity (mtv) required to initiate bed particle movement (indicated at the point where normalized bed height thickness reduces to zero) for bed with denser particles was much higher (1.07 m/s) as compared to lighter particles (0.8 m/s). this is attributed to the increased ability of any fluid to suspend lighter particles for a longer duration in the flow stream, especially in near horizontal sections, and hence, result in better transport efficiency [9]. li and wilde studied different particles which have a specific gravity in the range of 1.25 to 3.6. the bed erosion tests were conducted in a flow loop at different inclination angles. the results obtained agree with model predictions. more dense particles were difficult to clean from the test section. the efficiency of fluid was studied in terms of "transport ratio", defined as the ratio of injected to deposited solids concentration. a higher value of transport ratios indicates better solids removal capacity [10]. the result of the investigation showed that particles with low-density resulted in high transport ratios demonstrating easily removal of such particles. in addition, the solids concentration in a horizontal section was higher than that in a vertical well section for a given flow rate for same particle density. the solids concentration increases in each type of profile with an increase in particle density. cano et al. also recognized the importance of particle density on the transport efficiency of the cleanout fluids. high-density particles require increased hydrodynamic forces to be dislodged from the bed and carried by the cleaning fluid. the results obtained from all the studies mentioned above have a common finding that heavier particles are difficult to transport if other hydraulic parameters are kept constant. however, the challenge is to determine the magnitude of the effect of particle density and correlate its impact in predicting solids transport during the hole-cleaning. this study focuses on trying to solve this problem by utilizing data obtained in this study and published data in the literature to account for the effect of particle density on hole cleaning efficiency [11]. however, the challenge is to determine the magnitude of the effect of particle density and correlate its impact in predicting solids transport during the hole-cleaning. this study focuses on trying to solve this problem by utilizing data obtained in this study and published data in the literature to account for the effect of particle density on hole cleaning efficiency. mohammed alawami et al., calculated the cci in realtime with developed automatically system. based on rig sensors were used to generate thousands of raw values with continuously, these raw data makes the calculations for human is more easy and possible. the model is developed to take some well details, such as hole size and casing size with conjunction the raw data and use it as an input, to generate the cci. this system takes us one step closer toward the ultimate goal of having an integrated and fully automated hole cleaning evaluation and intervention tool that does not require any human involvement [12]. amel h. assi, used various drilling fluids to improve lifting capacity. three mud types were used including oil base mud, xanthan polymer and a mixture of cmc and bentonite. carrying capacity index (cci) has been used for assessment lifting capacity, the results show a good values were reported for xanthan polymer rather than other drilling fluids under study [13]. faleh and karrar investigated and assessed the influence of various nanoparticles on the performance of drilling fluids to make the drilling operation smooth, cost effective and efficient. we exam the effect of multi wall carbon nanotube and silicon oxide nanoparticles as nanomaterial to prepare drilling fluids samples 14]. moreover, other method was presented by ayad a. alhaleem to study the efficiency of drilling with casing operation in an iraqi oil field to overcome oil well control, minimizing the total cost through enhancing drilling efficiency, drilling with casing was proposed as an enabling technology. by using dwc technique, the total drill/case phase time was reduced up to 20% comparing to conventional drilling in the same field [15]. in this study the effect of cutting density on the efficiency of hole cleaning operation and related performance parameters was succinctly investigated. this was achieved by conducting a number of experimental tests using two types of cuttings with different sizes and density, while fluids with varying rheology were incorporated as cleanout fluids at varying flow rates. 2description of parameters for ctr estimation the cuttings used in this study were limited to limestone and anhydrite of different densities. the cuttings transport tests were conducted in a closed loop test section. two types of cuttings are used in the scope of this study light (low-density) limestone which having a specific gravity of 2.71 g/cc and heavy (high-density) anhydrite having a specific gravity of 2.97 g/cc. s. e. mohammed and f. h. m. almahdawi / iraqi journal of chemical and petroleum engineering 21,3 (2020) 1 8 3 a calculated initial weight was fed into the test section for each type of cuttings to maintain similar initial conditions of cuttings transport. preliminary cuttings transport tests indicated that 240 g of limestone was calculated based on assuming rop=2.31 ft/hr and porosity and density of this cutting equal 12% and 2.71 g/cc respectively. also, the weight measurement for anhydrite was depended on same value of rop in limestone calculations but, porosity and density of this cutting equal 0% and 2.97 g/cc respectively. cutting transport tests at a different flow rate were run for 3 minutes and a collected weight was recorded for each run 3 min. table 1 summarizes the test matrix for this investigation. table 1. range of data for cutting transport ratio estimation parameters range inclination angle θ (degree) 55 o -90 o mud weight (ppg) 8.75, 8.8, 9 pv (cp) 7.6, 13.5, 13.7 yp (lb/100ft 2 ) 11.3, 19.7, 30.2 flow rate (gpm) 48.43, 70.44, 92.46 cutting size (mm) 1.7, 2.36, 4 cutting density (ppg) 22.57, 24.47 3experimental work 3.1. configuration of the flow loop fig. 1 illustrated the cutting transport loop with the capacity to run all set experiments in a normal pressure and normal temperature system as seen in. the rig was simulated for field condition by assuming the drilling bit to be 8.5 inch (215.9 mm) and the drill pipe 5 inch (127 mm). the rig was designed to be 12.19 m (40 ft) long from iron, except the test section was made from pvc with long of 5.1 m (16.73 ft) consists of two pipes outer pipe: the inner and outer diameter for outer pipe was 4½” in (110 mm) and inner diameter 4” in (101.6 mm) respectively. the inner pipe with outer diameter equal 2” (50 mm). the inner pipe designed to be centralized with outer pipe. fig. 1. cuttings transport loo furthermore, the solid-liquid mixture was provided from a 0.55 m 3 (550 liters) container (mud tank) where the liquid pumped and combined with the drilling cuttings as illustrated in fig. 2. mud was agitating with a mixture instilled at bottom of mud tank. fig. 2. schematic of cuttings transport loop the actual drilling cuttings were used in this study with three diameters 1.7 mm (0.0669 in), 2.36 mm (0.0929in) and 4 mm (0.155 in) and of density of 2.71 and 2.97 gm/cm 3 . coarse sands taken from bai hassan oil field for well 192 from depth 1270 m to 1370 m were selected as solid particles. after cuttings were sift, washed and separated for three size 1.7, 2.36 mm and 4 mm then weight of 240 g (0.592 lb) and 300 g (0.661 lb) as test sample. the total amount of sift cuttings which were ready prior to each run approximated 10 kg (22 lb). all cutting sizes and types show in fig. 3 . (a) (b) (c) (d) (e) (f) fig. 3. a. limestone 4 mm, b. limestone 2.36 mm, c. limestone 1.7 mm, d. anhydrite 4 mm, e. anhydrite 2.36 mm, f. anhydrite 1.7 mm s. e. mohammed and f. h. m. almahdawi / iraqi journal of chemical and petroleum engineering 21,3 (2020) 1 8 4 3.2. description of mud system the drilling mud used in this experimental work has been prepared from water, caustic soda (sodium hydroxide) and bentonite, adding caustic soda and bentonite to water, mixing these components for six hours at a high and then medium speed. 3.3. experimental procedure in the beginning washing, drying and sieving the cutting drill then weight 240 g and 300 g as injection cutting for limestone and anhydrite respectively. 12 experiments for each run 6 experiments for limestone and other 6 for anhydrite was set up for inclination angle from (55 o -90 o ). three flow rates (48.43, 70.44, and 92.46 gpm) used in all of these experiments. repeat this procedure with new size and type of cuttings. after completed all experiments for the first run, increase yield point of mud (higher yield point) with added more bentonite and caustic soda then start second run with the same parameter in first run. calculate cutting transport ratio using equation below: ctr (%) = dry weight of cutting collected initial weight of cutting injected × 100 (1) summarized procedure can be seen in fig. 4: fig. 4. experimental procedure diagram 4results and discussion 4.1. description of mud system the three water-based mud systems were used for the investigation. all samples were prepared from bentonite and fresh water. a rotational viscometer (model 900) was used to measure the rheological properties of drilling fluids before and after each experiment. it was found that rheology of these fluids can be best described using a bingham plastic model as shown in fig. 5 and in table 2. shear rate (sec-1) 0 200 400 600 800 1000 1200 s h e a r s tr e s s ( lb /1 0 0 f t2 ) 0 10 20 30 40 50 60 mud1 mud2 mud3 fig. 5. shear stress vs. shear rate for different mud type table 2. rheology results for different mud type. mud type θ600 θ300 θ100 θ10 θ6 θ3 gel (10s) gel (10min) pv yp ρm marsh funnel mud1 27 19.2 12.3 8.7 8.2 8.2 10.9 15.4 7.6 11.3 8.75 36 mud2 46.7 33.3 21.9 14.7 14.6 14.6 18.2 20.3 19.6 13.5 8.83 46 mud3 57.3 43.6 31.2 22.9 22.9 22.8 26.6 40.1 30.2 13.7 9 56 s. e. mohammed and f. h. m. almahdawi / iraqi journal of chemical and petroleum engineering 21,3 (2020) 1 8 5 4.2. effect of cutting density on cleanout behavior the cutting density is one important factor that effect on cutting transport ratio in all type of wells. the main goal in this experimental work to study the different of cutting density on hole cleaning in three mud system. the density difference between fluid and cutting governs the required hydrodynamic force to lift or roll particle from the stationary bed into the flow stream. as expected, a heavier particle is more difficult to transport. in this study, two different cuttings rock densities with three sizes (1.7, 2.36 and 4mm) were used in flow loop experiments. the specific gravities of the limestone and anhydrite were 2.71 and 2.97. fig. 6 were showed the cutting transport ratio for limestone and anhydrite with different sizes and for all fluids varying inclination (55°,65°,75° 85°, and 90°). the results obtained show that, relatively, for all angle and all sizes we observed the cutting with light density transported more than heavy density. the graphs suggest that increase in cutting density at constant flow rate results in a reduction in cuttings transport performance. also, increasing in yield point and annular velocity leading to increases in hole cleaning efficiency for all sizes and for two types of cuttings. however, the effect of yield point is become small at high values of annular velocity. cutting transport efficiency is increasing with increase in inclination angle from 75 o -90 o and decrease at 65 o after that shows increase between 65 o -55 o for two types of cutting. the critical angle for cutting transport is improved at 65 degree. lastly, the heavy and large size of cutting is more difficult with transport. inclination angle (degree) 50 60 70 80 90 100 c t r ( % ) 0 20 40 60 80 100 120 1.64 ft/s and 2.71 gm/cc lim 2.39 ft/s and 2.71 gm/cc lim 3.14 ft/s and 2.71 gm/cc lim 1.64 ft/s and 2.97 gm/cc anh 2.39 ft/s and 2.97 gm/cc anh 3.14 ft/s and 2.97 gm/cc anh (a) inclination angle (degree) 50 60 70 80 90 100 c t r ( % ) 0 20 40 60 80 100 120 1.64 ft/s and 2.71 gm/cc lim 2.39 ft/s and 2.71 gm/cc lim 3.14 ft/s and 2.71 gm/cc lim 1.64 ft/s and 2.97 gm/cc anh 2.39 ft/s and 2.97 gm/cc anh 3.14 ft/s and 2.97 gm/cc anh (b) inclination angle (degree) 50 60 70 80 90 100 c t r ( % ) 0 20 40 60 80 100 120 1.64 ft/s and 2.71 gm/cc lim 2.39 ft/s and 2.71 gm/cc lim 3.14 ft/s and 2.71 gm/cc lim 1.64 ft/s and 2.97 gm/cc anh 2.39 ft/s and 2.97 gm/cc anh 3.14 ft/s and 2.97 gm/cc anh (c) inclination angle (degree) 50 60 70 80 90 100 c t r ( % ) 0 20 40 60 80 100 120 1.64 ft/s and 2.71 gm/cc lim 2.39 ft/s and 2.71 gm/cc lim 3.14 ft/s and 2.71 gm/cc lim 1.64 ft/s and 2.97 gm/cc anh 2.39 ft/s and 2.97 gm/cc anh 3.14 ft/s and 2.97 gm/cc anh (d) s. e. mohammed and f. h. m. almahdawi / iraqi journal of chemical and petroleum engineering 21,3 (2020) 1 8 6 inclination angle (degree) 50 60 70 80 90 100 c t r ( % ) 0 20 40 60 80 100 120 1.64 ft/s and 2.71 gm/cc lim 2.39 ft/s and 2.71 gm/cc lim 3.14 ft/s and 2.71 gm/cc lim 1.64 ft/s and 2.97 gm/cc anh 2.39 ft/s and 2.97 gm/cc anh 3.14 ft/s and 2.97 gm/cc anh (e) inclination angle (degree) 50 60 70 80 90 100 c t r ( % ) 0 20 40 60 80 100 120 1.64 ft/s and 2.71 gm/cc lim 2.39 ft/s and 2.71 gm/cc lim 3.14 ft/s and 2.71 gm/cc lim 1.64 ft/s and 2.97 gm/cc anh 2.39 ft/s and 2.97 gm/cc anh 3.14 ft/s and 2.97 gm/cc anh (f) inclination angle (degree) 50 60 70 80 90 100 c t r ( % ) 0 20 40 60 80 100 120 1.64 ft/s and 2.71 gm/cc lim 2.39 ft/s and 2.71 gm/cc lim 3.14 ft/s and 2.71 gm/cc lim 1.64 ft/s and 2.97 gm/cc anh 2.39 ft/s and 2.97 gm/cc anh 3.14 ft/s and 2.97 gm/cc anh (g) inclination angle (degree) 50 60 70 80 90 100 c t r ( % ) 0 20 40 60 80 100 120 1.64 ft/s and 2.71 gm/cc lim 2.39 ft/s and 2.71 gm/cc lim 3.14 ft/s and 2.71 gm/cc lim 1.64 ft/s and 2.97 gm/cc anh 2.39 ft/s and 2.97 gm/cc anh 3.14 ft/s and 2.97 gm/cc anh (h) inclination angle (degree) 50 60 70 80 90 100 c t r ( % ) 0 20 40 60 80 100 120 1.64 ft/s and 2.71 gm/cc lim 2.39 ft/s and 2.71 gm/cc lim 3.14 ft/s and 2.71 gm/cc lim 1.64 ft/s and 2.97 gm/cc anh 2.39 ft/s and 2.97 gm/cc anh 3.14 ft/s and 2.97 gm/cc anh (i) fig. 6. a. effect of cutting density on ctr for size 1.7 mm and yp=11.3, b. effect of cutting density on ctr for size 2.36 mm and yp=11.3 lb/100ft 2 , c. effect of cutting density on ctr for size 4 mm and yp=11.3 lb/100ft 2 , d. effect of cutting density on ctr for size 1.7 mm and yp=19.7 lb/100ft 2 , e. effect of cutting density on ctr for size 2.36 mm and yp=19.7 lb/100ft 2 , f. effect of cutting density on ctr for size 4 mm and yp=19.7 lb/100ft 2 , g. effect of cutting density on ctr for size 2.36 mm and yp=30.2 lb/100ft 2 , h. effect of cutting density on ctr for size 1.7 mm and yp=30.2 lb/100ft 2 , i. effect of cutting density on ctr for size 4 mm and yp=30.2 lb/100ft 2 s. e. mohammed and f. h. m. almahdawi / iraqi journal of chemical and petroleum engineering 21,3 (2020) 1 8 7 5conclusions based on this this study we show the cutting transport ratio and cleanout efficiency increase with increase flow rate for all yield point value of mud and inclination angle considered. increase in flow rate improves annular velocity acting on the cutting recovery. higher flow rate indicates higher annular velocity of mud acting to transport of the cutting, leading to improved cutting transport. the maximum cutting recovery has been observed at the maximum annular velocity (third velocity 3.14 ft/s) for all size and inclination angle. the effect of annular mud is become more in high inclination angle and high yield value of yp than other cases. the amount of cutting that can be transported much with increase in yield point of fluid. this case was showed for the same flow rate and inclination angle and for all cutting size. the effect of yield point will be low at the higher value of annular velocity. the direct relationship exists between cutting transport and inclination angle. the critical inclination angle exists between 65° and 75°. in this angle exists at which all fluids have similar performance, especially at low yp and minimum value of annular velocity and for all cutting size. nomenclatures and abbreviations no. parameter meaning unit 1 ctr cuttings transport ratio % 2 cci carrying capacity index % 3 mtv minimum transport velocity ft/sec 4 ecd equivalent circulating density ppg 5 q flow rate gpm 6 rpm pipe rotation per minute rpm 7 yp yield point lb/100ft 2 8 θ inclination angle degree 9 pv plastic viscosity cp 10 ρm mud density ppg 11 ρp cutting density ppg 12 dp cutting size mm references [1] pandya, s., goyal, s., & pandey, y, “optimizing the fracturing treatments by intersecting production data and fracture diagnostics”. society of petroleum engineers, november. 2015. [2] zamora, m. and hanson, p., “selected studies in high-angle hole cleaning”, 19th annual convention proceedings, volume 2, indonesian petroleum association, 1990, pages 411-425. [3] fraser, l., griffin, t., jabri, m., sones, g., stealman, m. and valco, p., “seamless fluids programs: a key to better well construction”, oilfield review, summer issue, schlumberger, 42-58. 1996. [4] li, j., misselbrook, j., sach, m, “sand cleanouts with coiled tubing: choice of process, tools and fluids”, journal of canadian petroleum technology 49(8):6982. 2010. [5] rolovic, r., weng, x., hill, s., robinson, g., zemlak, k., & najafov, j., “an integrated system approach to wellbore cleanouts with coiled tubing”. society of petroleum engineers.january.2004. [6] ozbayoglu, m., saasen, a., sorgun, m., svanes, k., “effect of pipe rotation on hole cleaning for waterbased drilling fluids in horizontal and deviated wells”. proc. iadc/spe asia pacific drill. technol. conf. exhib. 1–11, 2008. [7] ozbayoglu mehmet evren, osgouei reza ettehadi, ozbayoglu ahmet murat, yuksel ertan, “estimation of very”-difficult-to-identify" data for hole cleaning, cuttings transport and pressure drop estimation in directional and horizontal drilling”. iadc/spe asia pacific drill. technol. conf. exhib. 1–18, 2010. [8] pandya, s., “experimental study of proppant transport in horizontal and directional wells”. ms thesis, university of oklahoma. 2016. [9] nguyen, d., & rahman, s. s, , “a three-layer hydraulic program for effective cuttings transport and hole cleaning in highly deviated and horizontal wells”, society of petroleum engineers, january.1996. [10] li, j., & wilde, g. , “effect of particle density and size on solids transport and hole cleaning with coiled tubing”. society of petroleum engineers, january .2005. [11] cano, v., cardona, w. g., murphy, c., & de araujo, m., “improved ct well cleanout and milling procedures utilizing only non-viscous cleanout fluids”. society of petroleum engineers. 2016. [12] mohammed, m., s., & m. “a real-time indicator for the evaluation of hole cleaning efficiency”. society of petroleum engineers. 2019. [13] amel h. a. “enhancing the lifting capacity of drilling fluids in vertical oil wells”. iraqi journal of chemical and petroleum engineering, vol.18, pp.13 – 29, sep. 2017. [14] faleh h. m. & karrar s.” enhancement of drilling fluid properties using nanoparticles”. iraqi journal of chemical and petroleum engineering, vol.19, pp.21 – 26, june. 2018. [15] ayad a. alhaleem. “study the efficiency of drilling with casing operation in an iraqi oil field”. iraqi journal of chemical and petroleum engineering, vol.17, pp.47 – 52, june. 2016. https://www.onepetro.org/conference-paper/spe-178101-ms https://www.onepetro.org/conference-paper/spe-178101-ms https://www.onepetro.org/conference-paper/spe-178101-ms https://www.onepetro.org/conference-paper/spe-178101-ms http://archives.datapages.com/data/ipa/data/019/019002/411_ipa019b0411.htm http://archives.datapages.com/data/ipa/data/019/019002/411_ipa019b0411.htm http://archives.datapages.com/data/ipa/data/019/019002/411_ipa019b0411.htm http://archives.datapages.com/data/ipa/data/019/019002/411_ipa019b0411.htm https://connect.slb.com/~/media/files/resources/oilfield_review/ors96/sum96/06964256.pdf https://connect.slb.com/~/media/files/resources/oilfield_review/ors96/sum96/06964256.pdf https://connect.slb.com/~/media/files/resources/oilfield_review/ors96/sum96/06964256.pdf https://connect.slb.com/~/media/files/resources/oilfield_review/ors96/sum96/06964256.pdf https://www.onepetro.org/journal-paper/spe-113267-pa https://www.onepetro.org/journal-paper/spe-113267-pa https://www.onepetro.org/journal-paper/spe-113267-pa https://www.onepetro.org/journal-paper/spe-113267-pa https://www.onepetro.org/conference-paper/spe-89333-ms https://www.onepetro.org/conference-paper/spe-89333-ms https://www.onepetro.org/conference-paper/spe-89333-ms https://www.onepetro.org/conference-paper/spe-89333-ms https://www.onepetro.org/conference-paper/spe-114965-ms https://www.onepetro.org/conference-paper/spe-114965-ms https://www.onepetro.org/conference-paper/spe-114965-ms https://www.onepetro.org/conference-paper/spe-114965-ms https://www.onepetro.org/conference-paper/spe-114965-ms https://www.onepetro.org/conference-paper/spe-136304-ms https://www.onepetro.org/conference-paper/spe-136304-ms https://www.onepetro.org/conference-paper/spe-136304-ms https://www.onepetro.org/conference-paper/spe-136304-ms https://www.onepetro.org/conference-paper/spe-136304-ms https://www.onepetro.org/conference-paper/spe-136304-ms https://www.onepetro.org/conference-paper/spe-136304-ms https://shareok.org/handle/11244/34664 https://shareok.org/handle/11244/34664 https://shareok.org/handle/11244/34664 https://www.onepetro.org/conference-paper/spe-36383-ms https://www.onepetro.org/conference-paper/spe-36383-ms https://www.onepetro.org/conference-paper/spe-36383-ms https://www.onepetro.org/conference-paper/spe-36383-ms https://www.onepetro.org/conference-paper/spe-36383-ms https://www.onepetro.org/conference-paper/spe-94187-ms https://www.onepetro.org/conference-paper/spe-94187-ms https://www.onepetro.org/conference-paper/spe-94187-ms https://www.onepetro.org/conference-paper/spe-94187-ms https://www.onepetro.org/conference-paper/spe-179070-ms https://www.onepetro.org/conference-paper/spe-179070-ms https://www.onepetro.org/conference-paper/spe-179070-ms https://www.onepetro.org/conference-paper/spe-179070-ms https://www.onepetro.org/conference-paper/spe-196448-ms https://www.onepetro.org/conference-paper/spe-196448-ms https://www.onepetro.org/conference-paper/spe-196448-ms http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/63 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/63 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/63 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/63 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/162 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/162 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/162 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/162 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/81 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/81 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/81 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/81 s. e. mohammed and f. h. m. almahdawi / iraqi journal of chemical and petroleum engineering 21,3 (2020) 1 8 8 دراسة مختبرية لتقييم تأثير كثافة القطع الصخرية على كفاءة تنظيف جوف البئر في األبار المائلة واألفقية سهمي عدوان محمد و فالح المهداوي جامعة بغداد/قسم هندسة النفط الخالصة الدوران والسحب, إنخفاض إن كفاءة التنظيف الرديئة لجوف البئر ينتج عنها العديد من المشاكل مثل زيادة عزمي الطاقة الهيدروليكية, وكذلك مشكلة إستعصاء األنابيب. هذه المشاكل تؤدي الى زياة الكلف التشغيلية الممكن تجنبها والتي حاولت هذه الدراسة معالجتها.خالل هذه العمل تم دراسة تأثير كثافة القطع الصخرية بشكل كامل على كفاءة أجريت التجارب باستخدام منظومة مختبرية تم إعدادها لهذا الغرض ار المائلة واألفقية.تنظيف جوف البئر في األب م( كمنظومة تدفق و المصنعة من الحديد والبالستيك. مقطع األختبار تم إستخدامه من مادة 12قدم ) 40وبطول إن نسبة إنج. 2اخلي إنج, وقطر خارجي لإلنبوب الد 4م وبقطرداخلي لألنبوب الخارجي 5.1البالستك وبطول نقل القطع الصخرية يتم حسابها عن طريق الوزن أي توزين الكمية الخارجة بعد تجفيفها على الكمية المحقونة أي الكمية األولية حيث يتم هذه العملية في كل فحص. تم إختبار نسبة نقل القطع الصخرية لتأثير عوامل عدة منها: الصخرية, نقطة المطاوعة لطين الحفر, وزاوية ميل البئر. طريقة الفحص تتم معدل الجريان,حجم وكثافة القطع بتثبيت زاوية الميل ومن ثم معدل الجريان عم طريق الفلوميتر الخاص بقياس معدل التدفق, بعد ذلك يتم حقن الحجم حيث يتم جمع القطع دقاائق 3المطلوب من القطع الصخرية داخل مقطع األختبار بعدها يتم تشغيل المنظومة لمدة الصخرية الخارجة خالل ثالث دقائق وغسلها وتجفيها وتوزينها على الكمية األصلية لحساب نسبة النقل, وتكون هذه األختبارات بتثبيت قيمة نقطة المطاوعة للطين. كفاءة علىمتوسط تشير النتائج التي تم الحصول عليها من هذه الدراسة إلى أن كثافة القطع لها تأثير بسيط إلى جوف البئر. أيضا ، لوحظ تحسن في نسبة نقل القطع الصخرية كلما زادت سرعة الفراغ الحلقي وزادت زاوية تنظيف الميل. كذلك, بينت النتائج أن القطع الصخر ية ذات الحجوم المتوسطة والكبيرة تنقل بنسبة أكبر من القطع ذات وتصبح هذه الحالة عكسية عند القيم القليلة لنقطة الحجوم الصغيرة عند القيم العالية لنقطة المطاوعة لطين الحفر المطاوعة.باإلضافة الى ذلك,أوضحت النتائج بأن القطع الصخرية ذات الكثافة الكبيرة تنقل بنسية أقل مقارنة بالقطع اقعة بين الصضرية ذات الكثافة القليلة وهذا التأثير لجميع األحجام المستخدمة. وأخيرًا ، لوحظ بأن الزاوية الحرجة و لرسم جميع األشكال في هذه الورقة البحثية. sigma plot 12.5تم أستخدمبرنامج درجة. 75-65 الكلمات الدالة: نسبة نقل القطع, كثافة القطع الصلبة, كفاءة تنظيف البئر, نقطة المطاوعة. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.21 no.2 (june 2020) 7 – 14 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: yasser a. khudhaier , email: yasserabbasha@gmail.com, name: fadhil s. kadhim , email: fadhilkadhim47@yahoo.com , name: yousif k. yousif, email: yousifky@gmail.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. using artificial neural network to predict rate of penetration from dynamic elastic properties in nasiriya oil field yasser a. khudhaier a , fadhil s. kadhim a and yousif k. yousif b a petroleum technology department, university of technology, baghdad, iraq b ministry of higher education and scientific research, baghdad, iraq abstract the time spent in drilling ahead is usually a significant portion of total well cost. drilling is an expensive operation including the cost of equipment and material used during the penetration of rock plus crew efforts in order to finish the well without serious problems. knowing the rate of penetration should help in speculation of the cost and lead to optimize drilling outgoings .ten wells in the nasiriya oil field have been selected based on the availability of the data. dynamic elastic properties of mishrif formation in the selected wells were determined by using interactive petrophysics (ip v3.5) software based on the las files and log record provided. the average rate of penetration and average dynamic elastic properties for the studied wells was determined and listed with depth. laboratory measurements were conducted on core samples selected from two wells from the studied wells. ultrasonic device was used to measure the transit time of compressional and shear waves and to compare these results with log records. the reason behind that is to check the accuracy of the greenberg-castagna equation that was used to estimate the shear wave in order to calculate dynamic elastic properties. the model was built using artificial neural network (ann) to predict the rate of penetration in mishrif formation in the nasiriya oil field for the selected wells. the results obtained from the model were compared with the provided rate of penetration from the field and the mean square error (mse) of the model was 3.58 *10 -5 . keywords: rate of penetration, artificial neural network, dynamic elastic properties, nasiriya oil field received on 10/10/2019, accepted on 14/12/2019, published on 30/06/2020 https://doi.org/10.31699/ijcpe.2020.2.2 1introduction oil field developments are subject to drill wells in economical manners. for that reason, future management of oil field will face new obstacles to reduce overall costs, increase performance and reduce the probability of encountering problems[1]. drilling for energy search from the ground has shown considerable technological advances in the recent years[2]. different methods from different disciplines are being used now in drilling activities in order to obtain a safe and cost-effective well construction[3]. the first well drilled in a new field (a wildcat well) generally will have the highest cost. with increasing familiarity to the area optimized could be implemented in decreasing costs of each subsequent well to be drilled until a point is reached at which there is no more significant improvement. the relationship among drilling parameters are complex, so the efforts is to determine what combination of operating conditions result in minimum cost drilling[4]. the rate of penetration is important in drilling the wells that are required in the development process of the oil field. it is likely to finish the well as soon as possible without problems [5]. so in order to implement the optimization concept for drilling parameters and reducing the cost of drilling, data from the drilled wells in areas that have the same geological properties of the area that is going to be drilled and nearby wells are gathered and analyzed to start drilling the well at the lowest cost as possible[6]. the drilling process is a complex process including many factors some of them can be adjusted at a time to enhance the drilling process and they are changeable with time, these parameters called controllable parameters, for instance, rotary speed and weight on bit. the other parameters are difficult to control like depth and formation pressure. these parameters called uncontrollable parameters. predicting penetration rate includes some difficulties because it relies on both the controllable and uncontrollable parameters. many mathematical models have been proposed by several researchers to predict the penetration rate and to investigate the relationship between different drilling parameters and the penetration rate. teale [7] presented the concept of mechanical specific energy and the equation concluded in term of the operational parameters as follows: 𝑀𝑆𝐸 = 𝑊𝑂𝐵 ∗ [ 1 𝐴𝑏 + 13.33∗ 𝜇∗𝑁 𝑑𝑏∗𝑅𝑂𝑃 ] (1) http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:yasserabbasha@gmail.com mailto:fadhilkadhim47@yahoo.com mailto:yousifky@gmail.com http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2020.2.2 y. a. khudhaier et al. / iraqi journal of chemical and petroleum engineering 21,2 (2020) 7 14 8 where mse is the mechanical specific energy, wob is the weight on bit, n is the rotary speed, ab is the borehole area, 𝜇 is bit specific coefficient of sliding friction and rop is the penetration rate. bourgoyne and young [8] developed a model based on the multiple regression analysis of the field data gathered. the model describes the rop as a function of formation strength, formation compaction, formation depth, differential pressure, bit diameter, bit weight, bit wear, and bit hydraulics. the equation for predicting the penetration rate takes into account various drilling parameters as follows: 𝑅𝑂𝑃 = exp (a1 + ∑ ajxj) 8 j=2 (2) where a1 to a8 are constants that estimated by multiple linear regression. hareland and motahhari [9] developed a rop model based on hareland model for pdc bit assuming 100% cleaning efficiency: 𝑅𝑂𝑃 = 𝑊𝑓 ( 𝐺 𝑁𝑦 𝑊𝑂𝐵𝛼 𝑑𝑏 𝜎 ) (3) where: g is a coefficient determined based on bit and blade geometry. 𝑊𝑓 is the wear function calibrating rop values for a worn bit. 𝜎 unconfined rock strength. and it’s a function of wob, rpm, and rock strength at the drilling depth. all the previous models to predict rop were based on operational parameters and rock strength and did not include the dynamic elastic properties of rocks. in this research, the model focuses on this area to relate these properties with rop. artificial neural network design was inspired by the human brain. ann is applied in different fields, for instance, financial services, biomedical applications, time series prediction. due to neural network ability in solving non-linear problems, they were used widely in petroleum engineering. such application of neural network includes bit selection, reservoir characterization and enhanced oil recovery (eor)[10]. the perceptron was introduced by rosenblatt[11]. the perceptron receives many inputs (𝑿𝟏, 𝑿𝟐,𝑿𝟑, … . 𝑿𝑵 ) from all the neurons in the previous layer. and one output is coming out from it (𝒚). moreover, the perceptron has a bias weight denoted as(𝒘𝟎). during the training stage, the weights will be changed continuously. so, it is possible to reduce or to strengthen some neurons' weight to get different outputs. a linear combination which is the sum of the product of the weight of each previous neuron by their inputs and adding to the summation the bias value as follows: 𝒚 = ∑ 𝑥𝑖 𝑛 𝑖=0 . 𝑤𝑖 + 𝑤0 (4) where: (𝒙𝒊) is the output from the previous neuron or from the input layer, (𝒘𝒊) is the weight connecting the ( 𝒊𝒕𝒉) neuron from the previous layer to the (𝒋𝒕𝒉) neuron in the current layer, (𝒘𝟎) is the bias, (𝒚) is the weighted sum. after the weighted sum computed, this value should be entered in a function called activation function (𝝈𝐳) [12]. this concept is demonstrated in fig. 1. fig. 1. concept of the perceptron with 𝒏 inputs and one output[12] the sigmoid function is one type of activation function which has the shape of the "s" curve. sigmoid function sig(z) is sometimes called 'squashing' function, because it squashes the input to a value range between (0 and 1). this function is applied to the weighted sum of the outputs of the previous neuron to get the input of the present node [13]. to get the right outputs from the network we need to train the network in an iterative process. the network must be fed with a data set that contains the inputs and the outputs. the output from the network is called “predicted output”. the output from the data set is called “desired output” or the “target”. the predicted outputs are compared with the targets to estimate the error between the calculated and the actual output, subsequently, evaluating the performance of the network, for each iteration the weights are adjusted in order to get better results (closer to desired outputs). for this purpose, learning algorithms are used to get the job done[14]. there are two types of neural networks due to their learning techniques, supervised and unsupervised. in supervised neural networks, the output values are known. and in the case of unsupervised, the output is unknown. the backpropagation algorithm (bp) and marquardtlevenberg are the most familiar learning algorithms[15]. 2aim of this study in this study, an intelligent model was developed in order to be used in rate of penetration prediction based on bulk modulus, shear modulus and poisson’s ratio as inputs. this model was built and developed based on the data provided from nasiriya oil field which is the case study of this paper. thus, predicting the rop helps in speculating drilling cost in the study area. 3materials and methods 3.1. study area description nasiriya oil field is located on the arabian platform in dhi-qar governorate, southern of iraq, a zone with a gentle fold. the field is about 38 kilometers northwest the nasiriya, west of the zagros fold belt. the area of the field is located on an unstable shelf close to the arab platform (mesopotamian zone). y. a. khudhaier et al. / iraqi journal of chemical and petroleum engineering 21,2 (2020) 7 14 9 this zone characterized by the presence of subsurface anticlines and domes with variable extension. arabian shield suffered from erosion that put in a lot of clastic sediments (zubair formation). nasiriya oil field has reserves in the late cretaceous (mishrif limestone formation) and early cretaceous (yammama limestone formation). the mishrif formation (cenomanian-early turonian) represents a heterogeneous formation primarily characterized as organic detrital limestones, capped by limonitic freshwater limestones. it is thickest in the rumaila and zubair fields (270 m), in the nahrumr and majnoon fields along the iraq iran border it becomes (435 m) thick. and in abo amud field between kut and amara it is (380 m) thick. other isolated occurrences lie near kifl (255 m) and samarra (250 m)[16]. 3.2. data collection and research methodology the first step in the research methodology is the selection of wells in the nasiriya oil field. in this field, there are two sets of open hole logs for different depth intervals provided by schlumberger company (inoc, 1985; inoc, 2007). the first one from 1924 m to 2532 m and the other one from 2528 m to 3430 m. the first set is passed through mishrif carbonate formation which is the most important formation. whereas, the second set is passed through yammama carbonate formation which is one of the deepest reservoirs in the ns oil field. ns-1, ns-3, ns-4, ns-5, ns9, ns-15, ns-16, ns-18, ns-19, and ns-21 are selected for this study. five exploratory wells drilled in the nasiriya oil field with in the period 1978 -1987. all the picked wells are production wells and scattered to overlay wide area of the nasiriya oil field. this distribution gives a high stiffness in the field data. all logs are present for these wells (inoc, 2007). core samples were used in this research. laboratory measurements were conducted on the core samples to compare log reading and lab measurements. james instrument v-meter mark iv ultrasonic device was used for measuring the compressional waves’ velocities. the samples dimensions were (1) inch in diameter and (2) inches in length. after the samples preparation process, dynamic elastic properties which include bulk modulus, shear modulus, and poisson’s ratio are computed. then, the data were used to build an intelligent model using ann to predict the rate of penetration. the data set was divided into three categories training, testing and validation by 70%, 15%, and 15% respectively. the steps of developing (ann) model are as follows: 1selecting the data: after the dynamic elastic properties have been calculated by ip software and the rate of penetration records has been organized and listed with depth. the data must be analyzed and processed. 2building neural network model: the model is built by selecting properties of the network such as network topology, training algorithms and minimum accepted error between predicted and actual. 3testing the model: the model was tested by new data that wasn't used in the training stage and within the range of training data. 4implementing neural network the artificial neural network is used in many applications to model highly non-linear problems. sometimes ann models fast to build and give accurate results. the neural network model was built using the marquardt-levenberg training algorithm. two hidden layers were used; each layer has twenty hidden neurons with the sigmoid transfer function for the two hidden layers. one output layer and a linear transfer function between the last hidden layer and the output layer. the dynamic elastic properties (kb, mu, and pr) data from five wells (ns-1, ns-3, ns-4, ns-5, ns-18) were averaged and listed with depth. after averaging the data, they have been arranged in a form that the network accepts it in order to be used as input data for training the network. the number of epochs was set to 1000 iteration. the performance of the neural network model for rop prediction should be evaluated. in order to do this evaluation, a regression analysis between network outputs (rop predicted) and actual (rop) was hired. fig. 2 demonstrates regression analysis with a straight line stand for best regression between the net output (rop predicted) and the desired output (rop actual). fig. 2. regression for the rop model at training, validation, and testing to get an excellent fit line the slope must be one and the intercept must be zero. y. a. khudhaier et al. / iraqi journal of chemical and petroleum engineering 21,2 (2020) 7 14 10 good correlation coefficients (r) were obtained from the trained network which they were r = [0.96, 0.96, 0.94] during the training, testing and validation stages respectively. the mean square error between predicted and desired (rop) was (3.58*10 -5 ) as shown in fig. 3. fig. 3. mean square error for the network 5results and discussion after the clay volume and the type of lithology have been identified. shear wave velocity (vs) can be obtained by using the greenberg-castagna model which depends on the type of formation and clay volume calculations. then, bulk modulus, shear modulus and poisson's ratio are computed and listed against depth for mishrif formation of the studied wells. dynamic elastic properties were calculated for the ten selected wells. these results are in agreement with fjaer et al [17] and gercek [18]. the table 1 illustrates the average values of the dynamic elastic properties for the selected wells. the average values of (vp/vs) range from (1.87) to (1.91) where the velocity in (ft/s). these values agree with pickett [19], fadhil [20] and zinszner and pellerin [21] results for (vp/vs) values for limestone. the results of dynamic elastic properties are shown in fig. 4 for ns-16. fig. 4. dynamic elastic properties for mishrif formation (ns-16) laboratory measurements were conducted on samples of cores taken from ns-3 and ns-18 to measure compressional and shear waves velocities and to compare it with the results from the sonic log at the same depth. the non-destructive ultrasonic test was used to measure transit time for compressional and shear waves. james instrument v-meter mark iv device used for these measurements and it has an advanced microprocessor and equipped with the s-wave response (shear wave transducers). the results showed good agreement between laboratory measurements and log records with maximum absolute percentage error (ape) is 20% and minimum (ape) is 1%. due to convenience between the lab measurements and the shear waves obtained from greenberg-castagna model. greenberg-castagna model was used to estimate the shear wave velocities curve. table 1. average results for dynamic elastic properties fm well vp/vs kbgpa st.de v mugpa st.d ev pr st.dev m is h r if f o r m a t io n ns-1 1.88 23.7 5.7 11.1 2.9 0.300 0.018 ns-3 1.88 25.8 8.8 12.0 4.1 0.300 0.014 ns-4 1.87 23.4 6.0 10.9 3.0 0.299 0.011 ns-5 1.88 22.1 6.3 10.2 2.7 0.301 0.015 ns-9 1.90 20.6 8.5 8.6 4.0 0.305 0.017 ns-15 1.88 21.1 4.7 9.8 2.5 0.301 0.013 ns-16 1.91 20.7 6.4 9.4 3.5 0.307 0.019 ns-18 1.87 25.5 8.4 11.9 3.7 0.299 0.013 ns-19 1.88 24.8 7.7 11.6 3.6 0.300 0.015 ns-21 1.87 27.6 9.0 13.0 4.0 0.297 0.009 table 1 lists the dynamic elastic properties values for the studied wells. highest average value of bulk modulus was (27.6) gpa from ns-21. the minimum average value of bulk modulus was (20.6) gpa from ns-9. for the shear modulus, the minimum average value was (8.6) gpa from ns-9. the maximum average value was (13) gpa from ns-21. for the poisson’s ratio, the values where close together for the all wells. the minimum average value was (0.297) from ns-21 and the maximum was (0.307) from ns-16. standard deviation gives an idea about how the data are spread out around the mean (average). low standard deviation means that most of the numbers are close to the mean. higher standard deviation was obtained from ns-21 with a value of (9) for bulk modulus. in the other hand, the minimum value of standard deviation was obtained from ns-15 which was (4.7). the deviation around the mean was smaller for the shear modulus. largest deviation around the mean was (4.1) from ns-21. ns-15 gave low standard deviation around (2.5). in case of poisson’s ratio the highest value of standard deviation was (0.019) which gained from ns-16, while the lowest value of standard deviation obtained from ns-21 was (0.009). the rop values were supported as discrete points in drilling reports. then, linear regression was used to predict the values of rop along the depth of interest in all studied wells. y. a. khudhaier et al. / iraqi journal of chemical and petroleum engineering 21,2 (2020) 7 14 11 the correlation coefficient was (r 2 = 0.91). dynamic elastic properties were plotted against rate of penetration for the wells (ns-1, ns-3, ns-4, ns-5, and ns-18) as shown in fig.5. the bulk modulus is reciprocal of rock compressibility. so, as the value of this modulus increase, the rock resistance to penetration also increases. in the result, if the other operational parameters and rock properties held constant, low rate of penetration will be obtained. fig. 5 does not show a clear trend between bulk modulus and rop because of wide range of variety in bulk modulus. this is due to the heterogeneity of carbonate reservoirs. for the shear modulus, it’s the rock resistance for the applied shear force. its effect was the same as the effect of bulk modulus. from fig.5, at the top of formation where the values of bulk modulus and shear modulus were at minimum the rop was at its highest value. rop started to decrease as the elastic properties started to rise up along the depth of interest. the plot of bulk modulus and shear modulus versus rop for the wells (ns-9, ns-15, ns-16, ns-19, and ns21) is shown in fig. a1 in appendixa fig. 5. bulk modulus and shear modulus vs average rate of penetration (ns-1, ns-3, ns-4, ns-5, and ns-18) fig. 6 demonstrates the relationship between the poisson’s ratio and the rate of penetration for the wells (ns-1, ns-3, ns-4, ns-5, and ns-18). poisson’s ratio is the negative ratio of lateral strain to longitudinal strain. high poisson’s ratio means the rock has lateral strain higher than longitudinal strain. this means that the rock has more resistance to penetration process. as shown in fig. 6, the penetration rate was highest at the top of the mishrif formation where the poisson’s ratio was at its minimum values. as moving downward, the rop started to decrease as the poisson’s ratio increased. all curves have large deflections and non-clear trend. there are a lot of parameters that lead to change in the rop. also, the poisson’s ratio was plotted against rop in appeendix-a2. the same behavior was obtained for these wells fig. 6. poisson’s ratio vs average rate of penetration (ns1, ns-3, ns-4, ns-5, and ns-18) fig. 7 shows a plot between rop from field and the predicted rop by the ann model for the wells (ns-1, ns-3, ns-4, ns-5 and ns-18). the data from these wells where used to train and build the ann model. fig. 8 shows the predicted rop by the ann model for the wells (ns-9, ns-15, ns-16, ns-19 and ns-21). fig. 7. rop predicted by ann model versus rop actual (ns-1, ns-3, ns-4, ns-5, and ns-18) 1900 1920 1940 1960 1980 2000 2020 2040 2060 2080 2100 3.90 3.95 4.00 4.05 4.10 4.15 4.20 d e p t h ( m ) actual rop (m/hrs) predicted rop (m/hrs) ann y. a. khudhaier et al. / iraqi journal of chemical and petroleum engineering 21,2 (2020) 7 14 12 fig. 8. rop predicted by ann model versus rop actual (ns-9, ns-15, ns-16, ns-19, and ns-21) 6conclusions the results did not show strong dependency of rop on dynamic elastic properties. because the rate of penetration does not depend on the elastic properties only other properties has direct effect on rop like rock compressive strength, porosity, operational parameters, and bit hydraulics. as shown in fig. 5 and fig. 6, there are large variations in the values of dynamic elastic properties due to heterogeneity of carbonate reservoirs. the rop was inversely proportional with dynamic elastic properties. when the values of dynamic elastic properties decrease the rop values rise up. a low rate of penetration was obtained in mishrif formation which was between (3.7) and (4.1) m/hrs. based on the values of (vp/vs) ratio, the lithology of mishref formation was limestone with some shale points scattered. the ann model has a mean square error about 3.58*10 -5 . as a result, the model gave close results to the real data and can be used in (rop) prediction in similar area. highest average value of bulk modulus in mishrif formation was (27.6) gpa estimated from ns-21 while the lowest average value was (20.6) gpa from ns-9. for the shear modulus, the highest average value was (13) gpa observed from well ns-21 and the lowest average value was (8.6) gpa estimated from well ns-9. as for the poisson’s ratio, the highest average value in the mishrif formation was (0.307) from well ns-16 and the lowest average value was (0.297) from well ns-21. the bulk modulus showed high distribution of the values around the mean. the highest value of the standard deviation was (9) obtained from ns-21. in case of shear modulus, the highest value of standard deviation was (4.1) from ns-3. for the poisson’s ratio, the values were close and the distribution was not major. highest value of standard deviation was (0.019) obtained from ns-16. fig. 7 and fig. 8 display the difference between the predicted and the actual rop. nomenclature db bit diameter 𝜇 bit specific coefficient of sliding friction ab borehole area g coefficient determined based on bit and blade geometry 𝑁 rotary speed 𝜎 unconfined rock strength 𝑊𝑓 wear function calibrating rop values for a worn bit abbreviations ape absolute percentage error ann artificial neural network bp backpropagation kb bulk modulus vp compressional wave mse mean square error ns nasiriya pr poisson’s ratio rop rate of penetration mu shear modulus vs shear wave st.dev standard deviation wob weight on bit references [1] alssafar, saifalden y., and faleh hm al-mahdawi. "certain assessment of using mwcnt nps in drilling fluid to mitigate stick-slip problem during drilling operation system." iraqi journal of chemical and petroleum engineering 20, no. 3 (2019) 39-47. [2] majeed, majid m., and ayad a. alhaleem. "enhancing drilling parameters in majnoon oilfield." iraqi journal of chemical and petroleum engineering 20, no. 2 (2019) 71-75. [3] anemangely, mohammad, ahmad ramezanzadeh, behzad tokhmechi, abdollah molaghab, and aram mohammadian. "drilling rate prediction from petrophysical logs and mud logging data using an optimized multilayer perceptron neural network." journal of geophysics and engineering 15, no. 4 (2018) 1146-1159. [4] dhiman, annudeep singh. "rheological properties & corrosion characteristics of drilling mud additives." halifax: dalhousie university (2012). 1880 1900 1920 1940 1960 1980 2000 2020 2040 2060 2080 3.9 4 4.1 4.2 4.3 d e p t h ( m ) actual rop (m/hrs) predected rop ann (m/hrs) https://doi.org/10.31699/ijcpe.2019.3.6 https://doi.org/10.31699/ijcpe.2019.3.6 https://doi.org/10.31699/ijcpe.2019.3.6 https://doi.org/10.31699/ijcpe.2019.3.6 https://doi.org/10.31699/ijcpe.2019.3.6 https://doi.org/10.31699/ijcpe.2019.2.9 https://doi.org/10.31699/ijcpe.2019.2.9 https://doi.org/10.31699/ijcpe.2019.2.9 https://doi.org/10.31699/ijcpe.2019.2.9 https://academic.oup.com/jge/article/15/4/1146/5204266 https://academic.oup.com/jge/article/15/4/1146/5204266 https://academic.oup.com/jge/article/15/4/1146/5204266 https://academic.oup.com/jge/article/15/4/1146/5204266 https://academic.oup.com/jge/article/15/4/1146/5204266 https://academic.oup.com/jge/article/15/4/1146/5204266 https://academic.oup.com/jge/article/15/4/1146/5204266 https://cdn.dal.ca/content/dam/dalhousie/pdf/faculty/engineering/peas/mengprojects/2012mengprojects/annudeep%20dhiman,%20rheological%20properties%20&%20corrosion%20characteristics%20of.pdf https://cdn.dal.ca/content/dam/dalhousie/pdf/faculty/engineering/peas/mengprojects/2012mengprojects/annudeep%20dhiman,%20rheological%20properties%20&%20corrosion%20characteristics%20of.pdf https://cdn.dal.ca/content/dam/dalhousie/pdf/faculty/engineering/peas/mengprojects/2012mengprojects/annudeep%20dhiman,%20rheological%20properties%20&%20corrosion%20characteristics%20of.pdf y. a. khudhaier et al. / iraqi journal of chemical and petroleum engineering 21,2 (2020) 7 14 13 [5] alkinani, husam h., abo taleb t. al-hameedi, shari dunn-norman, ralph e. flori, steven a. hilgedick, madhi a. al-maliki, yousif q. alshawi, mortadha t. alsaba, and ahmed s. amer. "examination of the relationship between rate of penetration and mud weight based on unconfined compressive strength of the rock." journal of king saud university-science (2018). [6] alsenwar, malik. "ncs drilling data based rop modelling and its application." master's thesis, university of stavanger, norway, 2017. [7] teale, r. "the concept of specific energy in rock drilling." in international journal of rock mechanics and mining sciences & geomechanics abstracts, vol. 2, no. 1, (1965) pp. 57-73. pergamon, [8] bourgoyne jr, adam t., and f. s. young jr. "a multiple regression approach to optimal drilling and abnormal pressure detection." society of petroleum engineers journal 14, no. 04 (1974) 371-384. [9] motahhari, hamed reza, geir hareland, runar nygaard, and b. bond. "method of optimizing motor and bit performance for maximum rop." journal of canadian petroleum technology 48, no. 06 (2009): 44-49. [10] a. gupta, “neural networks in data processing,” vol. 5, no. 5 (2016) pp. 1638–1642. [11] rosenblatt, f. "the perceptron: a probabilistic model for information storage and organization in the brain." psychological review 65, no. 6 (1958): 386. [12] yang, linjie, ping luo, chen change loy, and xiaoou tang. "a large-scale car dataset for finegrained categorization and verification." in proceedings of the ieee conference on computer vision and pattern recognition, (2015) pp. 39733981. [13] huang, guang-bin, qin-yu zhu, and cheekheong siew. "extreme learning machine: a new learning scheme of feedforward neural networks." neural networks 2 (2004) 985-990. [14] hicks, warren g., and james e. berry. "application of continuous velocity logs to determination of fluid saturation of reservoir rocks." geophysics 21, no. 3 (1956) 739-754. [15] skorpil, vladislav, and jiri stastny. "neural networks and backpropagation algorithm." electron bulg sozopol (2006): 20-22. [16] al-ameri, th k., and m. d. al-zaidi. "geochemical correlation of mishrif formation in al-nasiriyah oil field/south of iraq." iraqi journal of science 55, no. 2supplement (2014) 750-759. [17] holt, r. m., o-m. nes, j. f. stenebraten, and e. fjær. "static vs. dynamic behavior of shale." in 46th us rock mechanics/geomechanics symposium. american rock mechanics association, 2012. [18] gercek, h. "poisson's ratio values for rocks." international journal of rock mechanics and mining sciences 44, no. 1 (2007) 1-13. [19] pickett, george r. "acoustic character logs and their applications in formation evaluation." journal of petroleum technology 15, no. 06 (1963) 659-667. [20] kadhim, fadhil sarhan. "cementation factor and carbonate formation properties correlation from well logs data for nasiriya field." ph.d. diss., universiti teknologi malaysia, 2016. [21] zinszner, bernard, and francois-marie pellerin. a geoscientist's guide to petrophysics. editions technip, 2007. appendices appendix-a1. bulk modulus and shear modulus vs average rate of penetration (ns-9, ns-15, ns-16, ns-19, and ns-21) appendix-a2. poisson’s ratio vs average rate of penetration (ns-9, ns-15, ns-16, ns-19, and ns-21) https://www.sciencedirect.com/science/article/pii/s1018364718310474 https://www.sciencedirect.com/science/article/pii/s1018364718310474 https://www.sciencedirect.com/science/article/pii/s1018364718310474 https://www.sciencedirect.com/science/article/pii/s1018364718310474 https://www.sciencedirect.com/science/article/pii/s1018364718310474 https://www.sciencedirect.com/science/article/pii/s1018364718310474 https://www.sciencedirect.com/science/article/pii/s1018364718310474 https://www.sciencedirect.com/science/article/pii/s1018364718310474 https://uis.brage.unit.no/uis-xmlui/handle/11250/2463436 https://uis.brage.unit.no/uis-xmlui/handle/11250/2463436 https://uis.brage.unit.no/uis-xmlui/handle/11250/2463436 https://www.sciencedirect.com/science/article/abs/pii/0148906265900227 https://www.sciencedirect.com/science/article/abs/pii/0148906265900227 https://www.sciencedirect.com/science/article/abs/pii/0148906265900227 https://www.sciencedirect.com/science/article/abs/pii/0148906265900227 https://www.onepetro.org/journal-paper/spe-4238-pa https://www.onepetro.org/journal-paper/spe-4238-pa https://www.onepetro.org/journal-paper/spe-4238-pa https://www.onepetro.org/journal-paper/spe-4238-pa https://www.onepetro.org/journal-paper/petsoc-09-06-44-tb https://www.onepetro.org/journal-paper/petsoc-09-06-44-tb https://www.onepetro.org/journal-paper/petsoc-09-06-44-tb https://www.onepetro.org/journal-paper/petsoc-09-06-44-tb https://www.onepetro.org/journal-paper/petsoc-09-06-44-tb http://ijarcet.org/wp-content/uploads/ijarcet-vol-5-issue-5-1638-1642.pdf http://ijarcet.org/wp-content/uploads/ijarcet-vol-5-issue-5-1638-1642.pdf https://psycnet.apa.org/record/1959-09865-001 https://psycnet.apa.org/record/1959-09865-001 https://psycnet.apa.org/record/1959-09865-001 https://www.cv-foundation.org/openaccess/content_cvpr_2015/html/yang_a_large-scale_car_2015_cvpr_paper.html https://www.cv-foundation.org/openaccess/content_cvpr_2015/html/yang_a_large-scale_car_2015_cvpr_paper.html https://www.cv-foundation.org/openaccess/content_cvpr_2015/html/yang_a_large-scale_car_2015_cvpr_paper.html https://www.cv-foundation.org/openaccess/content_cvpr_2015/html/yang_a_large-scale_car_2015_cvpr_paper.html https://www.cv-foundation.org/openaccess/content_cvpr_2015/html/yang_a_large-scale_car_2015_cvpr_paper.html https://www.cv-foundation.org/openaccess/content_cvpr_2015/html/yang_a_large-scale_car_2015_cvpr_paper.html https://ieeexplore.ieee.org/abstract/document/1380068 https://ieeexplore.ieee.org/abstract/document/1380068 https://ieeexplore.ieee.org/abstract/document/1380068 https://ieeexplore.ieee.org/abstract/document/1380068 https://pubs.geoscienceworld.org/geophysics/article-abstract/21/3/739/67291 https://pubs.geoscienceworld.org/geophysics/article-abstract/21/3/739/67291 https://pubs.geoscienceworld.org/geophysics/article-abstract/21/3/739/67291 https://pubs.geoscienceworld.org/geophysics/article-abstract/21/3/739/67291 https://ecad.tu-sofia.bg/et/2006/et2006%20book%201/circuits%20and%20systems/173%20paper-v_skorpil.pdf https://ecad.tu-sofia.bg/et/2006/et2006%20book%201/circuits%20and%20systems/173%20paper-v_skorpil.pdf https://ecad.tu-sofia.bg/et/2006/et2006%20book%201/circuits%20and%20systems/173%20paper-v_skorpil.pdf https://www.iasj.net/iasj?func=fulltext&aid=91932 https://www.iasj.net/iasj?func=fulltext&aid=91932 https://www.iasj.net/iasj?func=fulltext&aid=91932 https://www.iasj.net/iasj?func=fulltext&aid=91932 https://www.onepetro.org/conference-paper/arma-2012-542 https://www.onepetro.org/conference-paper/arma-2012-542 https://www.onepetro.org/conference-paper/arma-2012-542 https://www.onepetro.org/conference-paper/arma-2012-542 https://www.sciencedirect.com/science/article/pii/s136516090600075x https://www.sciencedirect.com/science/article/pii/s136516090600075x https://www.sciencedirect.com/science/article/pii/s136516090600075x https://www.onepetro.org/journal-paper/spe-452-pa https://www.onepetro.org/journal-paper/spe-452-pa https://www.onepetro.org/journal-paper/spe-452-pa http://eprints.utm.my/id/eprint/77938/1/fadhilsarhankadhimpfche2016.pdf http://eprints.utm.my/id/eprint/77938/1/fadhilsarhankadhimpfche2016.pdf http://eprints.utm.my/id/eprint/77938/1/fadhilsarhankadhimpfche2016.pdf http://eprints.utm.my/id/eprint/77938/1/fadhilsarhankadhimpfche2016.pdf https://books.google.iq/books?hl=en&lr=&id=fd_drmhlvuic&oi=fnd&pg=pr5&dq=%5b21%5d%09zinszner,+bernard,+and+francois-marie+pellerin.+a+geoscientist%27s+guide+to+petrophysics.+editions+technip,+2007.&ots=ecqueowvas&sig=pnbqnkez1qnn4nixkicde2-kh3i&redir_esc=y#v=onepage&q=%5b21%5d%09zinszner%2c%20bernard%2c%20and%20francois-marie%20pellerin.%20a%20geoscientist's%20guide%20to%20petrophysics.%20editions%20technip%2c%202007.&f=false https://books.google.iq/books?hl=en&lr=&id=fd_drmhlvuic&oi=fnd&pg=pr5&dq=%5b21%5d%09zinszner,+bernard,+and+francois-marie+pellerin.+a+geoscientist%27s+guide+to+petrophysics.+editions+technip,+2007.&ots=ecqueowvas&sig=pnbqnkez1qnn4nixkicde2-kh3i&redir_esc=y#v=onepage&q=%5b21%5d%09zinszner%2c%20bernard%2c%20and%20francois-marie%20pellerin.%20a%20geoscientist's%20guide%20to%20petrophysics.%20editions%20technip%2c%202007.&f=false https://books.google.iq/books?hl=en&lr=&id=fd_drmhlvuic&oi=fnd&pg=pr5&dq=%5b21%5d%09zinszner,+bernard,+and+francois-marie+pellerin.+a+geoscientist%27s+guide+to+petrophysics.+editions+technip,+2007.&ots=ecqueowvas&sig=pnbqnkez1qnn4nixkicde2-kh3i&redir_esc=y#v=onepage&q=%5b21%5d%09zinszner%2c%20bernard%2c%20and%20francois-marie%20pellerin.%20a%20geoscientist's%20guide%20to%20petrophysics.%20editions%20technip%2c%202007.&f=false y. a. khudhaier et al. / iraqi journal of chemical and petroleum engineering 21,2 (2020) 7 14 14 استخدام الشبكة العصبية االصطناعية للتنبؤ بمعدل االختراق من الخصائص المرنة الصخرية الديناميكية 2خلف يوسفيوسف و 1فاضل سرحان كاظم، 1ياسر عباس خضير ، العراقبغداد ,الجامعة التكنولوجية ،قسم تكنولوجيا النفط 1 ، العراقبغداد، وزارة التعليم العالي والبحث العلمي 2 الخالصة يمثل الوقت المستغرق في تقدم عملية الحفر جزًءا كبيًرا من إجمالي تكلفة البئر. حفر اآلبار عملية باهظة تكلفة المعدات والمواد المستخدمة أثناء اختراق الصخور باالضافة الى جهود الطاقم من أجل الثمن بما في ذلك في تخمين التكلفة لذلك معرفة معدل إنهاء البئر دون مشاكل خطيرة. معرفة معدل االختراق من شأنه أن يساعد في تلك المنطقة. تم اختيار االختراق في المنطقة التي على وشك ان تحفر يساعد في عملية تخمين كلفة الحفر عشرة آبار في حقل الناصرية النفطي بناًء على توفر البيانات. تم تحديد الخصائص المرنة الديناميكية لتكوين ( واستنادًا إلى ملفات ip v3.5) petrophysics interactiveالمشرف في اآلبار المحددة باستخدام برنامج las دراجها قبل الشركات. تم تحديد وتسجيالت اللوكات المقدمة من معدل اختراق اآلبار التي تمت دراستها وا الخصائص المرنة الديناميكية. أجريت قياسات مختبرية على عينات أساسية مختارة من مقابل العمق مع معدل ئج لقياس وقت العبور لموجات الضغط والقص ولمقارنة هذه النتا ultra-sonicبئرين. تم استخدام جهاز greenberg-castagnaبتسجيالت اللوك. السبب وراء ذلك هو التحقق من دقة معادلة الموديل المستخدم التي تم استخدامها لحساب موجات القص لحساب الخصائص المرنة الديناميكية للصخور. ية االصطناعية تم بناء الموديل باستخدام تقنية الذكاء االصطناعي وااللية المستخدمة كانت الشبكة العصب للتنبؤ بمعدل االختراق في تكوين مشرف في حقل نفط الناصرية النفطي لآلبار المختارة. تمت مقارنة النتائج الخطأ التربيعي التي تم الحصول عليها من الموديل مع معدل االختراق المقدم من تقارير الحفر وكان متوسط صطناعية.لموديل الشبكة العصبية اال 10-5* 3.58) ) .حقل الناصرية النفطي ,الخواص الديناميكية المرنة ,الشبكة العصبية االصطناعية ,معدل االختراق : الدالةالكلمات available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.23 no.3 (september 2022) 25 – 34 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: mohammed sattar jabbar , email: m.jabbar1207@coeng.uobaghdad.edu.iq, name: rana th. abd alrubaye, email: rana.thabet@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. adsorption isotherms and isosteric heat of adsorption of metal organic frameworks as gas storage for liquefied petroleum gas vehicle in iraq mohammed sattar jabbar and rana th. abd alrubaye chemical engineering department, college of engineering university of baghdad, baghdad, iraq. abstract this research provides a novel technique for using metal organic frameworks (hkust-1) as a gas storage system for liquefied petroleum gas (lpg) in iraqi vehicles to avoid the drawbacks of the currently employed method of lpg gas storage. a low-cost adsorbent called hkust-1 was prepared and characterized in this research to investigate its ability for propane storage at different temperatures (25, 30, 35, and 40 o c) and pressures of (1-7) bar. hkust-1 was made using a hydrothermal method and characterized using powder x-ray diffraction, bet surface area, scanning electron microscopic (sem), and fourier transforms infrared spectroscopy (ftir). the hkust-1 was produced using a hydrothermal technique and possesses a high crystallinity of up to 97%, surface area 3400 m 2 /g, and pore volume 0.7 cm 3 /g. the prepared adsorbent (hkust-1) tested using volumetric method, the maximum adsorption capacity of propane was (10.499 mmol/g) at a temperature of 298k and a pressure of 7 bar. furthermore, adsorption isotherm study was conducted to understand the system equilibrium (i.e., the fitting with one of the known models langmuir, freundlich, and temkin isotherm models). it was observed that the freundlich isotherm model fitted well the experimental data. the clausius-clapeyron equation was used to determine the heat of adsorption, and the results revealed that the heat of adsorption increased as the propane adsorption capacity increased. the prepared hkust-1, which has a large surface area and a high adsorption capacity, can be used as a major solution for gas storage for liquefied petroleum gas (lpg) in iraqi vehicles. keywords: metal organic frameworks, liquefied petroleum gas, adsorbed natural gas, isosteric heat of adsorption received on 21/03/2022, accepted on 11/07/2022, published on 30/09/2022 https://doi.org/10.31699/ijcpe.2022.3.4 1introduction liquefied petroleum gas (lpg) (also called as "propane autogas") is mostly composed of propane (c3 h8) with percentage (100% or 60% or 35% )and butane (c4 h10) with percentage ( 40% or 65%) depending on the country and region, with some unsaturated components propene (c3h6) and butene (c4h8). lpg is produced by "wet" natural gas or refining petroleum (crude oil). the lpg component are gases at ambient temperature and pressure, but is liquefied at high pressures (more than 20 bars) [1]. currently, lpg is a preferred internal-combustion engine fuel because it emits less pollution and leaves little solid residue, does not dilute lubricants, and has a high octane rating , therefore, it is considered as a clean alternative for gasoline [2]. the iraqi government is aiming to urge citizens to switch to clean, domestically produced fuel. in iraq, lpg (propane autogas) is being used as a clean vehicle fuel gas due to its low carbon emissions, low contamination risk, and environmentally friendly [3]. although lpg burns cleaner than other fuel oils, it does have some drawbacks, such as higher fuel consumption due to its lower volumetric energy density than gasoline, and lpg pressure vessels are only filled to 80% of their overall capacity to allow for thermal expansion of the contained liquid, necessitating a larger storage tank [4]. furthermore, because lpg has a low boiling point of about -50°c, it must be stored in pressurized steel tanks with a pressure of 20 bars or higher in order to convert the gases to their liquid state at room temperature [1]. the lpg drawbacks lead to the need of a heavier and larger metal tank with high-pressure. however, passenger car tanks should be light and constructed of carbon fibers, which are related to safety, cost, and space problems requirements, since the lpg tanks with these specifications are dangerous and expensive .as result, it was essential to find alternative method to store these gases for storing large amounts of gas. different techniques have been used to store natural gas, such as compressed natural gas (cng) at 200-300 bar or liquefied natural gas (lng) at -161.5 °c [5]. the principal disadvantage of cng is the need for the large and heavy tanks, as well as expensive multi-stage compression [6] http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:m.jabbar1207@coeng.uobaghdad.edu.iq mailto:rana.thabet@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2022.3.4 m. s.jabbar and r. th. a. alrubaye / iraqi journal of chemical and petroleum engineering 23,3 (2022) 25 34 26 whereas, the disadvantages of lng are the energy and cost associated with liquefaction at -161.5 o c[7]. presently, a new gas storage technique (adsorbed natural gas (ang)) is being employed as an alternative technology for storing natural gas under suitable conditions for mobile usage. this new technology (ang) stores the hydrocarbon gasses in porous materials placed in the tanks. porous materials act like a sponge, catching gas molecules [8]. this method allows for the same amount of gas to be stored as cng at a significantly lower pressure (40-50 bars), lowering operating expenses. furthermore, increasing the driving distance of a natural gas vehicle (ngv) by employing adsorbed natural gas technology with higher pressure [9]. many types of adsorbents, including zeolites, activated carbons [10], and metal organic frameworks (mofs) [5] [11] [12], were developed and evaluated for adsorbed natural gas (ang). mofs have been shown to have a higher methane storage capacity than other adsorbents [13] [14] [15]. mofs are a new class of crystalline porous materials that have drawn a lot of attention in the last two decades due to their large surface area (up to 5000 cm 2 /g), pore volume (up to 2 cm 3 /g), high thermal and chemical stabilities, and low densities (from 0.21 to 1 g/cm 3 ) [16], as well as their potential uses in gas storage, molecular separation, and other applications [17]. mofs have features over activated carbon and zeolite because of their simple tunable and adaptable structures, and high crystallinity [18]. additionally, it allows for the optimization of pore dimension and surface chemistry within metal-organic frameworks, which was previously impossible in zeolite materials [17]. mofs are the preeminent forum for producing unique multifunctional products when it comes to gas storage applications [19]. the current study employs an adsorption technique for lpg storage to solve the drawbacks of the lpg storage method presently used using a novel adsorbent. the adsorption technique involves filling tanks with porous storage materials to store lpg. previous studies on propane adsorption on activated carbons [20], zeolites 5a [21], and mofs were done in the separation field [22]. abedini et al. (2020) showed that mofs (hkust-1) have a greater adsorption capacity for propane than activated carbon and zeolites 5a when utilized to separate the mixture of propylene/propane [23]. hkust-1 has been utilized for propane separation until recently, but there has been no research for employing it as gas storage for propane. the hkust-1 (hong kong university of science and technology) is considered as one of the most important mofs due to its high pore volume, good water adsorption/desorption stability, large surface area, and chemical stability [10]. taking all of the facts into account, a new safe method of storing lpg gases that are used as fuel in vehicles is required to replace the greater cost and lower capacity of the current lpg vessel. as a result, hkust-1 was prepared, characterized, and investigated in this study in order to reduce the cost of current lpg vessels in vehicles. hkust-1 has been selected for this task because of its high surface area and micro pore volume that enable for effective adsorptiondesorption for storing and delivering high amounts of lpg. 2experimental work 2.1. materials hkust-1 was produced using copper (ii) nitrate trihydrate [cu (no3)2 .3h2o, 99 percent] and benzene 1, 3, 5 tricarboxylic acid (trimesic acid) (btc 95 percent) from sigma aldrich. absolute ethanol (c2h5oh) was from fisher scientific. the propane autogas (adsorbed gas) was supplied from a gulf gas company in baghdad (89.97 vol. %). 2.2. preparation of hkust-1 hkust-1 was produced using the hydrothermal process reported by hill et al. [24]. trimesic acid (0.42 g) was accurately measured and dissolved in 24 ml of a 1:1 solvent ratio (c2h5oh: h2o). following that, the solution was mixed for ten minutes. after that, the copper nitrate trihydrate (0.875 g) was added to the solution and well stirred for 10 minutes. the resulting blue solution was transferred to a 150 ml stainless steel teflon lined autoclave and heated to 100 o c for 30 hours in a furnace for crystallization once it was completely dissolved in the solvent. the reactor was then cooled to room temperature, resulting in the formation of a green crystalline powder, as illustrated in fig. 1. the powder was filtered and thoroughly washed in a 60 ml water-ethanol solution (1:1 vol percent). finally, the green powder was activated under vacuum at 100°c for 16 hours using a rotary dryer evaporator and stored in a closed vessel. fig. 1. synthesized hkust-1 m. s.jabbar and r. th. a. alrubaye / iraqi journal of chemical and petroleum engineering 23,3 (2022) 25 34 27 2.3. characterization of hkust-1 after degassing the sample to remove moisture content and other gases that induce blockage and lower surface area, the surface area analyzer (micrometrics asap2020, usa) was applied to measure the surface area and pore volume by nitrogen physical adsorption at 77 k, according to iso 9277-2010. a large surface area value indicates that the adsorbent's activity has increased as the activity site has increased [25]. an x-ray diffract meter (shimadzu srd 6000) with a 370° scan range, 40 kv tube voltage, 30 ma tube current, and 40 kv tube voltage was used to evaluate the samples. the structural and chemical bonds between mof molecules were studied using an ftir 8400s (600-4000) cm -1 shimadzu. the hkust-1 morphology was described using scanning electron microscopic analysis. 2.4. propane isotherms adsorption an experimental setup based on the volumetric method was used to estimate the equilibrium adsorption capacity of synthesized adsorbents, as shown in fig.2. the fittings are all connected to the copper pipes (1/4 inch). stainless steel cylinders measuring around 25 cm 3 used as reservoirs and adsorption cells. the gas pressure was recorded with a gauge (helicoid gauge) that ranged from (1-10 bar) and had a sensitivity of 0.02 percent and an accuracy of 1%. both the reservoir and the adsorption chamber are maintained at the same temperature using a water bath. before each experiment, a vacuum pump was used to evacuate the adsorption equilibrium measurement equipment. a cylinder connected to a pressure regulator supplies the feeding gas. the gas exit flow rate is controlled by a rotameter. temperatures of (25, 30, 35, 40) o c and pressures of (1, 3, 5, 7) bar would be used to estimate propane isotherms. nitrogen gas was used to determine the volume of the overall unit. the initial outgassing process was performed overnight under vacuum at 100°c. the degassed sample was then inserted in the adsorption chamber in a quantity of 0.2 g. all the valves were closed at the end of the degassing process to prepare the system for the experiments run. in experiment run, v3 and v4 valves opened, the gas was pumped into the reservoir chamber until it reached to equilibrium. v3 was closed when the pressure reached the equilibrium; v4 was remained open, and the pressure value was recorded. the v5 was then opened, allowing the gas to enter the adsorption chamber and achieving equilibrium. the amount of adsorbed gas was determined at equilibrium using the equations below [26]: q = ( ci−cf)vr−cf ɛ va w (1) where: (q) is amount of gas adsorbed (mmol/g), (c) is concentration (mmol/l) , (v) is volume of the vessel (l) , (ɛ) void fraction, (w) weight of adsorbent (g) , subscripts i,f,r,a refer to initial ,final, reservoir and adsorber respectively. ci and cf where calculate from equation of real gases [27]: p v= z n r t (2) where: c=n/v ci = pi zi r t (3) cf= pf zf r t (4) z compressibility factor of feed and out gases may be estimated according to the generalized equation [27]: z = 1 + b p r t (5) the coefficient of b can be determined as follows [27]: b = r tc pc (b o + ω b') (6) the coefficient of b o and b' may be calculated as follows [27]: b o = 0.083 0.422 tr1.6 (7) b' = 0.139 0172 tr4.2 (8) where: pc is critical pressure of propane (42.48 bar), tc is critical temperature of propane (369.8 k), r gas constant (8.314 l.kpa/ mol. k) and ω is centric factor (0.152). 1 2 3 � � i-3 i-4 � 4 5 9 10 6 7 8 11 12 13 14 15 16 1 gas cylinder 2 pressure regulator 3,4,5,12,13 valve 6,7,16 pressure gauge 8 thermometer 9 reservoir chamber 10 adsoprption chamber 11 water bath 15 vacuum pump 14 rotameter i-6i-7i-8 fig. 2. schematic diagram of apparatus used for adsorption equilibrium measurement m. s.jabbar and r. th. a. alrubaye / iraqi journal of chemical and petroleum engineering 23,3 (2022) 25 34 28 2.5. adsorption isotherms the adsorption behavior of gas (or vapor) is investigated by varying the applied gas (or vapor) pressure; the relationship between the amount of adsorbed and pressure is referred to as an adsorption isotherm ("iso" and "therm" denote equal and temperature, respectively) [28]. the adsorption isotherms were studied using the langmuir, freundlich, and temkin isotherms, eqs. ( 9, 10, and 11) respectively. langmuir equation is [29]: 1 qe = ( 1 qm kl ) 1 ce + 1 qm (9) freundlich equation is [30]: log (qe ) = log (kf) + 1 n log (ce) (10) temkin equation is [31]: qe= β lna + β lnce (11) where: qe [mmol g -1 ] is the amiount of gas uptake on adsorbent at equilibrium, ce [mmol l -1 ] is the equilibrium concentration of gas, qm [mmol g -1 ] is the adsorption capacity constant (the equilibrium adsorption amount for a full monolayer), kf is freundlich adsorption equilibrium constant, kl [l mmol -1 ] is langmuir adsorption equilibrium constant, 𝛽 related to the heat of adsorption and a(kt ) is equilibrium binding constant [j mmol -1 ]. 2.6. isosteric heat of adsorption the isosteric heat of adsorption (qst) (isosteric indicating constant loading) is also known as the heat of adsorption or enthalpy of adsorption. when developing adsorption processes, the isosteric heat of adsorption, which measures the change in adsorbent temperature during adsorption, is an important thermodynamic property to consider. adsorption heat is proportional to the binding energy between adsorbed molecules and the adsorbent, as well as interactions between adsorbates [32]. the two techniques of determining qst are experimentbased calculations and molecular simulations. the latter's simulated adsorption enthalpies are largely dependent on isotherms derived from grand canonical monte carlo simulations (gcms) utilizing the ensemble fluctuation approach [33]. direct and indirect calculations are two types of experiment-based calculations. in the direct technique, which employs a calorimetric-volumetric system, it is feasible to measure directly the emitted heat during adsorption using a calorimeter. because these systems are extremely complex and expensive, only a few studies use the direct approach to calculate qst [34]. the indirect method of calculating the isosteric enthalpy of adsorption as a function of the amount adsorbed (loading) using adsorption isotherms is by far the most general. in most cases, the adsorbate-adsorbent interaction energy is computed indirectly utilizing at least two adsorption isotherms (t1, t2) measured at close but different temperatures (δt ≈ 10-20 k). the most common method for obtaining adsorption isotherms is volumetric gas adsorption measurements [35].the isosteric heat of adsorption (qst) can be estimated by the clausiusclapeyron equation as[22]: qst = rt 2 ( ∂ ln p ∂t )q (12) the integration leads to: ln p = qst r t + c (13) where: qst (kj/mol) is isosteric heat of adsorption, t is temperature (k), p is the pressure (kpa), r is the gas constant and q is the adsorption amount (mmol/g). 3result and discussion 3.1. characterization of hkust-1 the xrd analysis showed a typical characterization peaks of hkust-1 with high purity phase, and a crystallinity of 97%, which is close to al-yassiry's work, which had 100% crystallinity under the similar conditions [36]. the hkust-1 bet analysis has a pore volume of (0.7 cm 3 /g) and a surface area of 3480 m 2 /g, which was similar to kareem's results (3635 m 2 /g) under the same operating conditions [18]. all of the ir analysis bands for hkust-1 were in good agreement with the ir analysis [37]. the presence of the –cooh groups in the organic ligand reacting with metal ions is indicated by a strong stretching vibration of carboxylate anions at (1608.63)1/cm as seen in fig. 3. a band painted at (3600–2800) 1/cm demonstrated the presence of water and –oh groups in the material's structure. the absence of cuo and cu2o in the synthesis product during the production of hkust-1 is indicated by peaks at (410, 500, 610, and 615) 1/cm. increased and changed carboxyl absorption from (3,100) to (3,600) 1/cm in hkust-1 revealed the loss of water molecules [38]. fig. 4 demonstrates that the ir analysis for hkust-1 does not change after the propane adsorption process, indicating that the adsorbent's composition did not change after desorption. sem images of the prepared hkust-1 at a magnification of 2062 x are shown in fig. 5. as seen in this figure, the synthesized metal-organic framework has an octahedral shape. this result is similar to the one found by lin, et al. [39]. m. s.jabbar and r. th. a. alrubaye / iraqi journal of chemical and petroleum engineering 23,3 (2022) 25 34 29 fig. 3. ftir of prepared hkust-1before adsorption fig. 4. ftir of prepared hkust-1 after adsorption fig. 5. sem image of the synthesized hkust-1 3.2 propane adsorption on hkust-1 a. temperature effect on propane adsorption capacity the relationship between the propane adsorption capacity q (mmol/g) and temperature is seen in fig. 6. at a pressure of 7 bar and a temperature of 298 k, the highest adsorption capacity was found to be 10.49 mmol/g. as can be seen in fig. 6, increasing the temperature causes the amount of adsorbed propane on the adsorbent to decrease, particularly at 7 bars. fig. 6 illustrates that increasing the temperature at constant pressure decreases the total quantity of adsorbed propane on the adsorbent, indicating that the process is exothermic. this can be explained by the fact that when the temperature increased, the propane adsorbed on the hkust-1 surface became unstable, leading in desorption of more propane molecules. lamia, et al. [40] found similar behavior of decreasing adsorption capacity when temperature is increased. additionally, the adsorption capacities in this study (7.44 mmol/g at 1 bar and 303k) were close to those predicted by rubes, et al [41] (at similar condition employing hkust-1 as an adsorbent for adsorption of propane and propylene), which were (7.3) mmol/g. fig. 6. adsorption capacity as a function of temperature b. pressure effect on propane adsorption capacity the influence of pressure on propane adsorption capacity was studied at a constant temperature in the range of 1 to 7 bars (25, 30, 35 and 40 oc). when pressure is increased, the propane adsorption capacity increases, as seen in fig. 7. this is because increased pressure increases momentum, which reduces the resistance to mass transfer between the adsorbent and the adsorbate, resulting in a greater number of gas molecules on the adsorption site. this figure also shows a relatively high adsorption capacity at 1 bar (7.61 mmol/g) due to the significant interaction between large numbers of carbon atoms in the structure of propane and the hkust1 surface. ponraj et al. [42] used a simulated isotherm of hkust-1 as an adsorbent to separate methane from ethane and propane at 298 k with pressures ranging from 0.001 to 100 bar, and found the similar behavior of greater adsorption capacity at low pressure. fig. 7. adsorption capacity as a function of pressure m. s.jabbar and r. th. a. alrubaye / iraqi journal of chemical and petroleum engineering 23,3 (2022) 25 34 30 3.3. adsorption isotherms the langmuir, freundlich, and temkin isotherms were used to investigate the adsorption isotherms. these isotherms link propane intake per unit mass of adsorbent (qe) to the concentration of adsorbate in the gas phase at equilibrium (ce). a. langmuir isotherm equilibrium data for propane adsorption on the hkust-1 were fitted using the linearized langmuir equation described in eq. 9. fig. 8 shows a linear plot of equilibrium concentration (1/ce) versus equilibrium adsorption (1/qe). the langmuir constants (kl and qm) were calculated using the slope (1/qm kl) and the intercept of the plot (1/qm) ,as shown in table 1. the observed correlation coefficients (r 2 ) at 298, 303, 308, and 313 k were 0.8063, 0.8047, 0.8278, and 0.8392, respectively, according to the results obtained and listed in table 1; the isotherm data does not fit the langmuir equation. b. temkin isotherm equilibrium data for propane adsorption on the hkust-1 were fitted using the linearized temkin equation described in eq. 11. fig. 9 shows a linear plot of equilibrium concentration (ln ce) vs. adsorption capacity (qe). the temkin constants (kt and β) were calculated using the slope (β) and intercept of the plot (β ln kt), as shown in table 1. the observed correlation coefficients (r 2 ) at 298, 303, 308, and 313 k were 0.9076, 0.9135, 0.9346, and 0.9465, respectively, according to the results obtained and listed in table 1; the isotherm values fit the temkin equation well. c. freundlich isotherm the propane adsorption equilibrium data were carefully investigated using the freundlich isotherm. to fit the equilibrium data for propane adsorption on the hkust-1, the linearized freundlich equation described by eq. 10 was employed. fig. 10 shows a linear plot of (log ce) vs (log qe). the freundlich constants (kf and n) were calculated using the slope (1/n) and the plot intercept (log kf) and listed in table 1. the observed correlation coefficients at 298, 303, 308, and 313 k were 0.9345, 0.9369, 0.9531, and 0.9613, respectively, according to the results obtained and listed in table 1; the isotherm values fit the freundlich equation well. the results show that adsorption experimental data is suitable for temkin and freundlich models; however, when the r 2 values for the freundlich and temkin models are compared, the r 2 values for the freundlich model are greater than those for the temkin model. these results indicate that the freundlich model is more suitable with propane adsorption on hkust-1. in this research, the values of n at equilibrium were more than unity, indicating that the slope (1/n) was closer to zero, indicating a more heterogeneous adsorption process. table 1. isotherm parameters for propane adsorption on hkust1 isotherm parameters temperature (298 k) temperature (303 k) temperature (308 k) temperature (313 k) langmuir (qm) 9.8232 9.3809 9.0171 8.6655 langmuir (kl) 0.3467 0.3826 0.4053 0.4561 langmuir (r 2 ) 0.8063 0.8047 0.8278 0.8392 freundlich (kf) 5.9375 5.9020 5.8237 5.8398 freundlich (n) 9.7561 10.5708 11.1982 12.3762 freundlich (r 2 ) 0.9345 0.9369 0.9531 0.9613 temkin (β) 0.9056 0.8041 0.7316 0.6404 temkin (kt) 383.1521 878.5400 1699.2534 5708.72027 temkin (r 2 ) 0.9076 0.9135 0.9346 0.9465 fig. 8. langmuir isotherm fig. 9. temkin isotherm fig. 10. freundlich isotherm m. s.jabbar and r. th. a. alrubaye / iraqi journal of chemical and petroleum engineering 23,3 (2022) 25 34 31 3.4. isosteric heat خf adsorption for the clausius-clapeyron technique, the two adsorption isotherms must be fitted with the same continuous function, such as a langmuir, dual-site langmuir, toth, sips, jovanovic, dubinin-radushkevic, freundlich-langmuir, or other fit [43]. a. clausius-clapeyron approach for isosteric heat of adsorption calculation the same model must be used for the two isotherms at two temperatures (298 and 313 k). most mofs have a freundlich-langmuir isotherm, which can be fitted using the equation below [35]. q = 𝑎∗𝑏∗(𝑃)^𝑐 1+𝑏∗(𝑃)^𝑐 (14) where: q is the amount adsorbed (the loading) in mmol g – 1 , a is the maximal loading in mmol g –1 , p the pressure in kpa, c the heterogeneity exponent and b the affinity constant (1/kpa c ). by using origin program the curve in fig.7 is fitting to fig. 11. fig. 11. adsorption isotherms after fitting by freundlichlangmuir isotherm using origin program rearrange equation (14) and substitute the fitting parameters (a,b, and c) to determine the pressure at any temperature and the same loading. equation (14) become: p(q) = √ 𝑞 𝑎∗𝑏−𝑞∗𝑏 𝑐 (15) now, plot ln(p) versus t at the same loading as shown in fig. 12 and find slop of every line which result and calculate qst (qst = slope * r) were r is universal gas constant and plot qst versus amount adsorbed(q) as shown in fig. 13. fig. 12. ln p v.s 1/t fig. 13. isosteric heat of adsorption as a function of the amount adsorbed the isosteric heat of adsorption increased as the adsorption capacity increased, as seen in fig. 13. significant lateral interactions between adsorbates at hkust-1 sites cause this increase. the propane molecules preferentially bind at cage center sites, followed by adsorption at cage window sites, as explained by rubes [36]. the adsorption enthalpies rise as propane loading increases because the adsorbates at the cage center and cage window sites have strong lateral interactions. when the isosteric heat of adsorption increased with coverage (due to increasing the lateral interaction between adsorbate-adsorbate interactions while decreasing the binding energy between adsorbate molecules and the adsorbent surface), this resulted in a decrease in the amount of propane molecules that could be adsorbed and a decrease in the amount of gas delivered at desorption due to more gas molecules remaining in adsorbent sites due to the increased lateral interaction. 4conclusions in this work, the hkust-1 was successfully prepared and used as an effective adsorbent for propane gas. the hkust-1 was produced using a hydrothermal technique and possesses a high crystallinity of up to 97%, surface area 3400 m 2 /g, and pore volume 0.7 cm 3 /g. adsorption was utilized to store propane using the prepared hkust1. m. s.jabbar and r. th. a. alrubaye / iraqi journal of chemical and petroleum engineering 23,3 (2022) 25 34 32 according to the experiments, the largest propane adsorption capacity on hkust-1 was obtained around (10.499 mmol/g) at temperature 25 °c and pressure7 bar. according to the adsorption isotherm results, the equilibrium data were best described by the freundlich isotherm model, which means heterogeneous surfaces of hkust-1 (i.e., each site is occupied by multiple particles) and physical adsorption. the isosteric heat of adsorption increased as adsorption capacity increased. significant lateral interactions between the molecules adsorbed on hkust-1sites caused this increase. references [1] müller, u., hesse, m., pütter, h. and yaghi, o.m., basf se and university of michigan, 2008. metalorganic framework materials for gaseous hydrocarbon storage. u.s. patent 7,343,747. [2] demirbas, a., 2002. fuel properties of hydrogen, liquefied petroleum gas (lpg), and compressed natural gas (cng) for transportation. energy sources, 24(7), pp.601-610. [3] arapatsakos, karkanis, katirtzoglou and pantokratoras, 2008. liquid petroleum gas (lpg) and natural gas (ng) as fuels on diesel engine–dual fuel engine .recent advances in fluid mechanics and heat & mass transfer, 154-161. [4] raslavičius, l., keršys, a., mockus, s., keršienė, n. and starevičius, m., 2014. liquefied petroleum gas (lpg) as a medium-term option in the transition to sustainable fuels and transport. renewable and sustainable energy reviews, 32, pp.513-525. [5] makal, t.a., li, j.r., lu, w. and zhou, h.c., 2012. methane storage in advanced porous materials. chemical society reviews, 41(23), pp.7761-7779. [6] mason, j.a., veenstra, m. and long, j.r., 2014. evaluating metal–organic frameworks for natural gas storage. chemical science, 5(1), pp.32-51. [7] dobrota, đ., lalić, b. and komar, i., 2013. problem of boil-off in lng supply chain. transactions on maritime science, 2(02), pp.91-100. [8] chang, k.j. and talu, o., 1996. behavior and performance of adsorptive natural gas storage cylinders during discharge. applied thermal engineering, 16(5), pp.359-374. [9] mota, j.b., rodrigues, a.e., saatdjian, e. and tondeur, d., 1997. dynamics of natural gas adsorption storage systems employing activated carbon. carbon, 35(9), pp.1259-1270. [10] chui, s.s.y., lo, s.m.f., charmant, j.p., orpen, a.g. and williams, i.d., 1999. a chemically functionalizable nanoporous material [cu3 (tma)2 (h2o)3] n. science, 283(5405), pp.1148-1150. [11] menon, v.c. and komarneni, s., 1998. porous adsorbents for vehicular natural gas storage: a review. journal of porous materials, 5(1), pp.43-58. [12] morris, r.e. and wheatley, p.s., 2008. gas storage in nanoporous materials. angewandte chemie international edition, 47(27), pp.4966-4981. [13] furukawa, h., ko, n., go, y.b., aratani, n., choi, s.b., choi, e., yazaydin, a.ö., snurr, r.q., o’keeffe, m., kim, j. and yaghi, o.m., 2010. ultrahigh porosity in metal-organic frameworks. science, 329(5990), pp.424-428. [14] perry iv, j.j., perman, j.a. and zaworotko, m.j., 2009. design and synthesis of metal–organic frameworks using metal–organic polyhedra as supermolecular building blocks. chemical society reviews, 38(5), pp.1400-1417. [15] yaghi, o.m., o'keeffe, m., ockwig, n.w., chae, h.k., eddaoudi, m. and kim, j., 2003. reticular synthesis and the design of new materials. nature, 423(6941), pp.705-714. [16] eddaoudi, m., moler, d.b., li, h., chen, b., reineke, t.m., o'keeffe, m. and yaghi, o.m., 2001. modular chemistry: secondary building units as a basis for the design of highly porous and robust metal− organic carboxylate frameworks. accounts of chemical research, 34(4), pp.319-330. [17] li, j.r., kuppler, r.j. and zhou, h.c., 2009, “selective gas adsorption and separation in metal– organic frameworks”, chemical society reviews, 38(5), pp.1477-1504. [18] kareem, h.m. and alrubaye, r.t.a., 2019, “synthesis and characterization of metal organic frameworks for gas storage”, in iop conference series: materials science and engineering, 518(6), p. 062013. [19] li, h., li, l., lin, r.b., zhou, w., zhang, z., xiang, s. and chen, b., 2019, “porous metal-organic frameworks for gas storage and separation: status and challenges”, energychem, 1(1), p.100006. [20] jarvelin, h. and fair, j.r., 1993, “adsorptive separation of propylene-propane mixtures”, industrial & engineering chemistry research, 32(10), pp.22012207. [21] divekar, s., nanoti, a., dasgupta, s., chauhan, r., gupta, p., garg, m.o., singh, s.p. and mishra, i.m., 2016, “adsorption equilibria of propylene and propane on zeolites and prediction of their binary adsorption with the ideal adsorbed solution theory”, journal of chemical & engineering data, 61(7), pp.2629-2637. [22] bao, z., alnemrat, s., yu, l., vasiliev, i., ren, q., lu, x. and deng, s., 2011, “adsorption of ethane, ethylene, propane, and propylene on a magnesiumbased metal–organic framework”, langmuir, 27(22), pp.13554-13562. [23] abedini, h., shariati, a. and khosravi-nikou, m.r., 2020. adsorption of propane and propylene on m-mof-74 (m= cu, co): equilibrium and kinetic study. chemical engineering research and design, 153, pp.96-106. https://patents.google.com/patent/us7343747b2/en https://patents.google.com/patent/us7343747b2/en https://patents.google.com/patent/us7343747b2/en https://patents.google.com/patent/us7343747b2/en https://www.tandfonline.com/doi/abs/10.1080/00908312.2002.11877434 https://www.tandfonline.com/doi/abs/10.1080/00908312.2002.11877434 https://www.tandfonline.com/doi/abs/10.1080/00908312.2002.11877434 https://www.tandfonline.com/doi/abs/10.1080/00908312.2002.11877434 https://www.academia.edu/download/83199615/fluhe-25.pdf https://www.academia.edu/download/83199615/fluhe-25.pdf https://www.academia.edu/download/83199615/fluhe-25.pdf https://www.academia.edu/download/83199615/fluhe-25.pdf https://www.academia.edu/download/83199615/fluhe-25.pdf https://www.sciencedirect.com/science/article/pii/s136403211400063x https://www.sciencedirect.com/science/article/pii/s136403211400063x https://www.sciencedirect.com/science/article/pii/s136403211400063x https://www.sciencedirect.com/science/article/pii/s136403211400063x https://www.sciencedirect.com/science/article/pii/s136403211400063x https://pubs.rsc.org/en/content/articlehtml/2012/cs/c2cs35251f https://pubs.rsc.org/en/content/articlehtml/2012/cs/c2cs35251f https://pubs.rsc.org/en/content/articlehtml/2012/cs/c2cs35251f https://pubs.rsc.org/en/content/articlehtml/2014/sc/c3sc52633j https://pubs.rsc.org/en/content/articlehtml/2014/sc/c3sc52633j https://pubs.rsc.org/en/content/articlehtml/2014/sc/c3sc52633j https://hrcak.srce.hr/file/161548 https://hrcak.srce.hr/file/161548 https://hrcak.srce.hr/file/161548 https://www.sciencedirect.com/science/article/pii/1359431195000178 https://www.sciencedirect.com/science/article/pii/1359431195000178 https://www.sciencedirect.com/science/article/pii/1359431195000178 https://www.sciencedirect.com/science/article/pii/1359431195000178 https://www.sciencedirect.com/science/article/pii/s0008622397000754 https://www.sciencedirect.com/science/article/pii/s0008622397000754 https://www.sciencedirect.com/science/article/pii/s0008622397000754 https://www.sciencedirect.com/science/article/pii/s0008622397000754 https://www.science.org/doi/abs/10.1126/science.283.5405.1148 https://www.science.org/doi/abs/10.1126/science.283.5405.1148 https://www.science.org/doi/abs/10.1126/science.283.5405.1148 https://www.science.org/doi/abs/10.1126/science.283.5405.1148 https://link.springer.com/article/10.1023/a:1009673830619 https://link.springer.com/article/10.1023/a:1009673830619 https://link.springer.com/article/10.1023/a:1009673830619 https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.200703934 https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.200703934 https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.200703934 https://www.science.org/doi/abs/10.1126/science.1192160 https://www.science.org/doi/abs/10.1126/science.1192160 https://www.science.org/doi/abs/10.1126/science.1192160 https://www.science.org/doi/abs/10.1126/science.1192160 https://www.science.org/doi/abs/10.1126/science.1192160 https://pubs.rsc.org/en/content/articlehtml/2009/cs/b807086p https://pubs.rsc.org/en/content/articlehtml/2009/cs/b807086p https://pubs.rsc.org/en/content/articlehtml/2009/cs/b807086p https://pubs.rsc.org/en/content/articlehtml/2009/cs/b807086p https://pubs.rsc.org/en/content/articlehtml/2009/cs/b807086p https://www.nature.com/articles/nature01650 https://www.nature.com/articles/nature01650 https://www.nature.com/articles/nature01650 https://www.nature.com/articles/nature01650 https://pubs.acs.org/doi/abs/10.1021/ar000034b https://pubs.acs.org/doi/abs/10.1021/ar000034b https://pubs.acs.org/doi/abs/10.1021/ar000034b https://pubs.acs.org/doi/abs/10.1021/ar000034b https://pubs.acs.org/doi/abs/10.1021/ar000034b https://pubs.acs.org/doi/abs/10.1021/ar000034b https://pubs.rsc.org/en/content/articlehtml/2009/cs/b802426j https://pubs.rsc.org/en/content/articlehtml/2009/cs/b802426j https://pubs.rsc.org/en/content/articlehtml/2009/cs/b802426j https://pubs.rsc.org/en/content/articlehtml/2009/cs/b802426j https://iopscience.iop.org/article/10.1088/1757-899x/518/6/062013/meta https://iopscience.iop.org/article/10.1088/1757-899x/518/6/062013/meta https://iopscience.iop.org/article/10.1088/1757-899x/518/6/062013/meta https://iopscience.iop.org/article/10.1088/1757-899x/518/6/062013/meta https://iopscience.iop.org/article/10.1088/1757-899x/518/6/062013/meta https://www.sciencedirect.com/science/article/pii/s2589778019300065 https://www.sciencedirect.com/science/article/pii/s2589778019300065 https://www.sciencedirect.com/science/article/pii/s2589778019300065 https://www.sciencedirect.com/science/article/pii/s2589778019300065 https://pubs.acs.org/doi/pdf/10.1021/ie00022a001 https://pubs.acs.org/doi/pdf/10.1021/ie00022a001 https://pubs.acs.org/doi/pdf/10.1021/ie00022a001 https://pubs.acs.org/doi/pdf/10.1021/ie00022a001 https://pubs.acs.org/doi/abs/10.1021/acs.jced.6b00294 https://pubs.acs.org/doi/abs/10.1021/acs.jced.6b00294 https://pubs.acs.org/doi/abs/10.1021/acs.jced.6b00294 https://pubs.acs.org/doi/abs/10.1021/acs.jced.6b00294 https://pubs.acs.org/doi/abs/10.1021/acs.jced.6b00294 https://pubs.acs.org/doi/abs/10.1021/acs.jced.6b00294 https://pubs.acs.org/doi/abs/10.1021/acs.jced.6b00294 https://pubs.acs.org/doi/abs/10.1021/la2030473 https://pubs.acs.org/doi/abs/10.1021/la2030473 https://pubs.acs.org/doi/abs/10.1021/la2030473 https://pubs.acs.org/doi/abs/10.1021/la2030473 https://pubs.acs.org/doi/abs/10.1021/la2030473 https://www.sciencedirect.com/science/article/pii/s0263876219304848 https://www.sciencedirect.com/science/article/pii/s0263876219304848 https://www.sciencedirect.com/science/article/pii/s0263876219304848 https://www.sciencedirect.com/science/article/pii/s0263876219304848 https://www.sciencedirect.com/science/article/pii/s0263876219304848 m. s.jabbar and r. th. a. alrubaye / iraqi journal of chemical and petroleum engineering 23,3 (2022) 25 34 33 [24] hill, p., al-janabi, n., torrente-murciano, l., garforth, a., gorgojo, p., siperstein, f., & fan, x., 2015, “mapping the cu-btc metal–organic framework (hkust-1) stability envelope in the presence of water vapour for co2 adsorption from flue gases”, chemical engineering journal, 281, pp. 669–677. [25] li, y., wang, l.-j., fan, h.-l., shangguan, j., wang, h., & mi, j., 2015, “removal of sulfur compounds by a copper-based metal organic framework under ambient conditions”, energy and fuels, 29(1), pp. 298–304. [26] ahmed j .m, 2005, “adsorption of light hydrocarbons by molecular sieves”, ph.d. thesis, college of engineering, baghdad university. [27] smith, j. m., van ness, h.c. and abbot, m. m. (2005) introduction to chemical engineering thermodynamics, 7th ed., new york, mcgraw-hill. [28] furukawa, h. (2018) synthesis and characterization of metal–organic frameworks.in: glover, t.g. and mu, b. (eds.) gas adsorption in metal-organic frameworks: fundamentals and applications. crc press., pp.19-70. [29] langmuir, i., 1918. the adsorption of gases on plane surfaces of glass, mica and platinum. journal of the american chemical society, 40(9), pp.1361-1403. [30] freundlich, h.k., 1909. eine darstellung der chemie der kolloide und verwandte gebiete. kapillarchemie. leipzig. [31] tempkin, m.i. and pyzhev, v.j.a.p.c., 1940. kinetics of ammonia synthesis on promoted iron catalyst. acta phys. chim. ussr, 12(1), p.327. [32] tsivadze, a.y., aksyutin, o.e., ishkov, a.g., knyazeva, m.k., solovtsova, o.v., men’shchikov, i.e., fomkin, a.a., shkolin, a.v., khozina, e.v. and grachev, v.a., 2019. metal-organic framework structures: adsorbents for natural gas storage. russian chemical reviews, 88(9), p.925. [33] du, z., nie, x., deng, s., zhao, l., li, s., zhang, y. and zhao, j., 2020, “comparative analysis of calculation method of adsorption isosteric heat: case study of co2 capture using mofs”, microporous and mesoporous materials, 298, p.110053. [34] sumida, k., rogow, d.l., mason, j.a., mcdonald, t.m., bloch, e.d., herm, z.r., bae, t.h. and long, j.r., 2012. carbon dioxide capture in metal–organic frameworks. chemical reviews, 112(2), pp.724-781. [35] nuhnen, a. and janiak, c., 2020, “a practical guide to calculate the isosteric heat/enthalpy of adsorption via adsorption isotherms in metal–organic frameworks, mofs”, dalton transactions, 49(30), pp.10295-10307. [36] alyassiry, a.a. and alrubaye, r.t.a., 2020, march. desulfurization of model gasoline using metal organic frame-work. in aip conference proceedings (vol. 2213, no. 1, p. 020090). aip publishing llc. [37] hoang, t. c., nguyen thi, t. v., luu, c. l., nguyen, t., bui, t. h., duy nguyen, p. h., & pham thi, t. p., 2013, “synthesis of mof-199 and application to co2 adsorption”, advances in natural sciences: nanoscience and nanotechnology, 4(3), p. 035016. [38] alrubaye, r.t.a. and kareem, h.m., 2019, “carbon dioxide adsorption on mof-199 metalorganic framework at high pressure”, in iop conference series: materials science and engineering, 557(1), p. 012060. [39] lin, k. s., adhikari, a. k., ku, c. n., chiang, c. l., & kuo, h. (2012) ‘synthesis and characterization of porous hkust-1 metal organic frameworks for hydrogen storage’, international journal of hydrogen energy. elsevier ltd, 37(18), pp. 13865–13871. [40] lamia, n., jorge, m., granato, m.a., paz, f.a.a., chevreau, h. and rodrigues, a.e., 2009, “adsorption of propane, propylene and isobutane on a metal–organic framework: molecular simulation and experiment”, chemical engineering science, 64(14), pp.3246-3259. [41] rubes, m., wiersum, a.d., llewellyn, p.l., grajciar, l., bludsky, o. and nachtigall, p., 2013. adsorption of propane and propylene on cubtc metal–organic framework: combined theoretical and experimental investigation. the journal of physical chemistry c, 117(21), pp.11159-11167. [42] ponraj, y.k. and borah, b., 2020. separation of methane from ethane and propane by selective adsorption and diffusion in mof cu-btc: a molecular simulation study. journal of molecular graphics and modelling, 97, p.107574. [43] tóth, j., 1995. uniform interpretation of gas/solid adsorption. advances in colloid and interface science, 55, pp.1-239. https://www.sciencedirect.com/science/article/pii/s1385894715009857 https://www.sciencedirect.com/science/article/pii/s1385894715009857 https://www.sciencedirect.com/science/article/pii/s1385894715009857 https://www.sciencedirect.com/science/article/pii/s1385894715009857 https://www.sciencedirect.com/science/article/pii/s1385894715009857 https://www.sciencedirect.com/science/article/pii/s1385894715009857 https://www.sciencedirect.com/science/article/pii/s1385894715009857 https://pubs.acs.org/doi/abs/10.1021/ef501918f https://pubs.acs.org/doi/abs/10.1021/ef501918f https://pubs.acs.org/doi/abs/10.1021/ef501918f https://pubs.acs.org/doi/abs/10.1021/ef501918f https://pubs.acs.org/doi/abs/10.1021/ef501918f https://www.taylorfrancis.com/chapters/edit/10.1201/9780429469770-2/synthesis-characterization-metal%e2%80%93organic-frameworks-hiroyasu-furukawa https://www.taylorfrancis.com/chapters/edit/10.1201/9780429469770-2/synthesis-characterization-metal%e2%80%93organic-frameworks-hiroyasu-furukawa https://www.taylorfrancis.com/chapters/edit/10.1201/9780429469770-2/synthesis-characterization-metal%e2%80%93organic-frameworks-hiroyasu-furukawa https://www.taylorfrancis.com/chapters/edit/10.1201/9780429469770-2/synthesis-characterization-metal%e2%80%93organic-frameworks-hiroyasu-furukawa https://www.taylorfrancis.com/chapters/edit/10.1201/9780429469770-2/synthesis-characterization-metal%e2%80%93organic-frameworks-hiroyasu-furukawa https://pubs.acs.org/doi/pdf/10.1021/ja02242a004 https://pubs.acs.org/doi/pdf/10.1021/ja02242a004 https://pubs.acs.org/doi/pdf/10.1021/ja02242a004 https://iopscience.iop.org/article/10.1070/rcr4873/meta https://iopscience.iop.org/article/10.1070/rcr4873/meta https://iopscience.iop.org/article/10.1070/rcr4873/meta https://iopscience.iop.org/article/10.1070/rcr4873/meta https://iopscience.iop.org/article/10.1070/rcr4873/meta https://iopscience.iop.org/article/10.1070/rcr4873/meta https://www.sciencedirect.com/science/article/pii/s1387181120300561 https://www.sciencedirect.com/science/article/pii/s1387181120300561 https://www.sciencedirect.com/science/article/pii/s1387181120300561 https://www.sciencedirect.com/science/article/pii/s1387181120300561 https://www.sciencedirect.com/science/article/pii/s1387181120300561 https://pubs.acs.org/doi/full/10.1021/cr2003272 https://pubs.acs.org/doi/full/10.1021/cr2003272 https://pubs.acs.org/doi/full/10.1021/cr2003272 https://pubs.acs.org/doi/full/10.1021/cr2003272 https://pubs.acs.org/doi/full/10.1021/cr2003272 https://pubs.rsc.org/en/content/articlehtml/2020/dt/d0dt01784a https://pubs.rsc.org/en/content/articlehtml/2020/dt/d0dt01784a https://pubs.rsc.org/en/content/articlehtml/2020/dt/d0dt01784a https://pubs.rsc.org/en/content/articlehtml/2020/dt/d0dt01784a https://pubs.rsc.org/en/content/articlehtml/2020/dt/d0dt01784a https://aip.scitation.org/doi/abs/10.1063/5.0000242 https://aip.scitation.org/doi/abs/10.1063/5.0000242 https://aip.scitation.org/doi/abs/10.1063/5.0000242 https://aip.scitation.org/doi/abs/10.1063/5.0000242 https://iopscience.iop.org/article/10.1088/2043-6262/4/3/035016/meta https://iopscience.iop.org/article/10.1088/2043-6262/4/3/035016/meta https://iopscience.iop.org/article/10.1088/2043-6262/4/3/035016/meta https://iopscience.iop.org/article/10.1088/2043-6262/4/3/035016/meta https://iopscience.iop.org/article/10.1088/2043-6262/4/3/035016/meta https://iopscience.iop.org/article/10.1088/2043-6262/4/3/035016/meta https://iopscience.iop.org/article/10.1088/1757-899x/557/1/012060/meta https://iopscience.iop.org/article/10.1088/1757-899x/557/1/012060/meta https://iopscience.iop.org/article/10.1088/1757-899x/557/1/012060/meta https://iopscience.iop.org/article/10.1088/1757-899x/557/1/012060/meta https://iopscience.iop.org/article/10.1088/1757-899x/557/1/012060/meta https://www.sciencedirect.com/science/article/pii/s0360319912009986 https://www.sciencedirect.com/science/article/pii/s0360319912009986 https://www.sciencedirect.com/science/article/pii/s0360319912009986 https://www.sciencedirect.com/science/article/pii/s0360319912009986 https://www.sciencedirect.com/science/article/pii/s0360319912009986 https://www.sciencedirect.com/science/article/pii/s0360319912009986 https://www.sciencedirect.com/science/article/pii/s0009250909002504 https://www.sciencedirect.com/science/article/pii/s0009250909002504 https://www.sciencedirect.com/science/article/pii/s0009250909002504 https://www.sciencedirect.com/science/article/pii/s0009250909002504 https://www.sciencedirect.com/science/article/pii/s0009250909002504 https://www.sciencedirect.com/science/article/pii/s0009250909002504 https://pubs.acs.org/doi/abs/10.1021/jp401600v https://pubs.acs.org/doi/abs/10.1021/jp401600v https://pubs.acs.org/doi/abs/10.1021/jp401600v https://pubs.acs.org/doi/abs/10.1021/jp401600v https://pubs.acs.org/doi/abs/10.1021/jp401600v https://pubs.acs.org/doi/abs/10.1021/jp401600v https://www.sciencedirect.com/science/article/pii/s1093326319310083 https://www.sciencedirect.com/science/article/pii/s1093326319310083 https://www.sciencedirect.com/science/article/pii/s1093326319310083 https://www.sciencedirect.com/science/article/pii/s1093326319310083 https://www.sciencedirect.com/science/article/pii/s1093326319310083 https://www.sciencedirect.com/science/article/pii/0001868694002263 https://www.sciencedirect.com/science/article/pii/0001868694002263 https://www.sciencedirect.com/science/article/pii/0001868694002263 m. s.jabbar and r. th. a. alrubaye / iraqi journal of chemical and petroleum engineering 23,3 (2022) 25 34 34 وحرارة االمتزاز لألطر العضوية المعدنية المستخدمة لتخزين الغاز األيزوثيرمي االمتزاز البترولي المسال في المركبات العراقية محمد ستار جبار و رنا ثابت عبد الربيعي جامعة بغداد, كلية الهندسة, قسم الهندسة الكيمياوية الخالصة ( كنظام تخزين للغاز البترولي hkust-1المعدنية )يقدم هذا البحث تقنية جديدة الستخدام األطر العضوية ( في المركبات العراقية لتجنب عيوب الطريقة المستخدمة حالًيا لتخزين غاز البترولي المسال. تم lpgالمسال ) وتم فحصها في هذا البحث للتحقق من قدرتها على hkust-1تحضير مادة مازة منخفضة التكلفة تسمى (. تم تصنيع 7-1) bar( وضغوط 25، 30، 35، 40 ) ℃ات حرارة مختلفة تخزين البروبان في درج hkust-1 باستخدام طريقة حرارية مائية وتم وصف خصائصه باستخدام حيود األشعة السينية ، ومساحة أظهرت نتائج األشعة (.ftir( ، و األشعة تحت الحمراء )sem، والمسح المجهري األلكتروني ) betسطح بينما أظهرت نتائج تحليل المساحة السطحية ,%97المحضر نسبة تبلور جيدة hkust-1السينية لـ تم اختبار المادة الماصة (.0.7cm3/gوحجم مسامي ) (3480m2/gمساحة السطحية مقدارها ) الحصول على 10.499) هي( باستخدام الطريقة الحجمية ، وكانت السعة القصوى المتزاز البروبان hkust-1المحضرة ) mmol/g298 درجة حرارة ( عندk و ضغطbar 7 لفهم توازن النظام)أي .تم فحص نتائج االمتزاز األيزوثيرمي ( واظهرت نتائج االمتزاز temkinو langmuirو freundlichالمالئمة مع أحد النماذج المعروفة ) أظهرت النتائج التي تم الحصول عليها من حسابات .freundlichموديل بشكل جيد تناسب انها األيزوثيرمي أن حرارة االمتزاز تزداد مع زيادة سعة االمتزاز. clausiusclapeyronحرارة األمتزاز بواسطة معادلة المحضر والذي يتميز بمساحة كبيرة وقدرة امتزاز عالية كحل رئيسي لتخزين الغاز hkust-1يمكن استخدام ( في المركبات العراقية.lpgالبترولي المسال ) العضوية المعدنية, الغاز البترولي المسال, الغاز الطبيعي الممتز, حرارة األمتزاز. الكلمات الدالة: األطر iraqi journal of chemical and petroleum engineering vol.12 no.1 (march 2011) issn: 1997-4884 oily wastewater treatment using expanded beds of activated carbon and zeolite sawsan a. m. mohammed, ibtihage faisal and maha m. alwan chemical engineering department – college of engineering – university of baghdad – iraq abstract two types of adsorbents were used to treat oily wastewater, activated carbon and zeolite. the removal efficiencies of these materials were compared to each other. the results showed that activated carbon performed some better properties in removal of oil. the experimental methods which were employed in this investigation included batch and column studies. the former was used to evaluate the rate and equilibrium of carbon and zeolie adsorption, while the latter was used to determine treatment efficiencies and performance characteristics. expanded bed adsorber was constructed in the column studies. in this study, the adsorption behavior of vegetable oil (corn oil) onto activated carbon and zeolite was examined as a function of the concentration of the adsorbate, contact time, adsorbent dosage and amount of coagulant salt(calcium sulphate) added . the adsorption data was modeled with freundlich and langmuir adsorption isotherms. and it was found that the adsorption process on activated carbon and zeolite fit the freundlich isotherm model. the amount of oil adsorbed increased with increasing the contact time, but longer mixing duration did not increase residual oil removal from wastewater due to the coverage of the adsorbent surface with oil molecules. it was found that as the dosage of adsorbent increased, the percentage of residual oil removal also increased. the effects of adsorbent type and amount of coagulant salt(calcium sulphate) added on the breakthrough curve were studied in details in the column studies. expanded bed behavior was modeled using the richardson-zaki correlation between the superficial velocity of the feed stream and the void fraction of the bed at moderate reynolds number. keywords: oil removal; adsorption; expanded beds; wastewater treatment; zeolite, activated carbon. iraqi journal of chemical and petroleum engineering university of baghdad college of engineering oily wastewater treatment using expanded beds of activated carbon and zeolite vol.12 no.1 (march 2011) introduction one of the most challenging problems today is the removal of oil from wastewater. large amounts of wastewater are generated by industrial companies that produce or handel oil and other organic compounds, both immiscible and miscible in water. oily wastewater discharged into the environment causes serious pollution problems since the biodegradability of oil is very low and oily wastewater hinders biological processing at sewage treatment plants. petroleum and petrochemical plants are potential oil sources for pollution inland water caused by runoff from oil fields, refineries and process effluent [1]. removal of dissolved and emulsified oils is achieved by using activated carbon or membrane filtration. the effluent from those operations contains almost no oil. several types of sorbents have been studied for the removal of oil from water by a packed bed filter such as sawdust, activated carbon, peat, bentonite, and organoclay [2]. current technologies for oil removal include filtration, gravity separation, induced floatation, ultrafiltration, adsorption, and biological treatment. an oil and water mixture can be classified as free oil for oil droplets larger than 150 μm, dispersed oil with oil droplets in the range of 20-150 μm, and emulsified oil with oil droplets smaller than 20 μm. a wastewater, where the oil in the oilwater mixture is not present in the form of droplets is said to be soluble [3]. the principles of liquid-solid fluidization have been extensively studied. a key work in the field was presented by richardson and zaki [3] more than 50 years ago. the equation predicts a linear correlation between the logarithms of superficial fluid velocity ( 0 v ) and the void fraction of the bed ( )1( s  for fluidized bed [4].   ts vnv log1loglog 0   ………. (1) where s  and t v are the solid fraction of the expanded bed and the terminal settling velocity of the particle at infinite dilution  0 s  , respectively. the superficial velocity 0 v is determined by dividing the volumetric flow rate of the feed stream by the cross sectional area of the column. the solid fraction s  of the expanded bed at height h can be obtained by: h h s 0 0   ………… (2) where 0  , and 0 h , are the solid fraction and height of the bed at zero flow stream, respectively. wen and yu [5] estimated the terminal velocity at moderate reynolds number using the following equation:   p ll lp t d g v 31 22 225 4             ……….... (3) for 0.4<re<500 the main objective of this research is to remove oil from water using activated carbon and zeoilte as the adsorbents. the effect of sawsan a. m. mohammed, ibtihage faisal and maha m. alwan vol.12 no.1 (march 2011) process variables such as adsorbent dosage, contact time, and amount of coagulant salt(calcium sulphate) added on the removal efficiency of oil was studied in order to determine the optimum process conditions. the adsorption equilibrium data were obtained to investigate which isotherm model provided the best fit for the adsorption process. experimental procedure the adsorbents used in this study were granular activated carbon and zeolite. the characteristics of adsorbents are reported in table (1). table (1): major characteristics of adsorbents. property activated carbon zeolite density, kg/m 3 1350 1545 bet surface area, m 2 /g 1100 630 bed porosity 0.45 0.25 particle diameter (dp), mm 0.8 0.25 adsorption isotherm measurements oil in water emulsion samples were prepared by mixing corn oil in distilled water with initial concentrations (c0) ranged 500024000 ppm. equilibrium studies were conducted at room temperatures by employing the batch adsorption technique. weighed amounts of adsorbent (2-8 g) were taken in conical flasks containing 100 ml of oily water of known concentration (ρl=977 kg/m 3 for the highest concentration). the solutions were agitated at 150 rpm using a teflon coated half-inch bar on a corning magnetic stirrer for a specified period of contact time ranged 5-25 min. upon equilibrium, the solutions were filtered and the concentration of residual oil was measured using a uv spectrometer (shimadzu model 160a) with an absorbance wavelength of 450 nm. column studies the schematic representation of experimental set-up is shown in fig.(1); it consists of a glass column of 2.45 cm internal diameter and a height of 75 cm. the column was packed with adsorbent to a height of 8 cm. the adsorbent particles are supported by a wire mesh fitted at the column bottom. fig.1: schematic diagram of expanded bed (1.adsorber, 2 flow meter, 3.pump, 4.feed tank, 5. treated effluent tank, 6.sampling point, 7.to drain, 8.feed. the flow rate of wastewater was 50 l/h. the effluents from the bed were analyzed for oil content at chosen intervals of time until breakthrough occurs. the minimum fluidized velocity for particles (vmf) had been estimated 2 3 4 5 6 7 1 8 oily wastewater treatment using expanded beds of activated carbon and zeolite vol.12 no.1 (march 2011) to be (1.410 3 m/s) for activated particles and (2.110 – 4 m/s) for zeolite using the following equation [6]:                7.330408.07.33 2 3 2 l lplp lp l mf gd d v     ….… (4) the height of the bed was measured over a certain range of feed velocities. results and discussion adsorption isotherms the successful representation of the dynamic adsorptive separation of solute from solution onto an adsorbent depends upon a good description of the equilibrium separation between the two phases. adsorption equilibrium is the amount of solute being adsorbed onto the adsorbent. at this point, the equilibrium solution concentration remains constant. by plotting solid phase concentration against liquid phase concentration, it is possible to depict the equilibrium adsorption isotherm. fig.(2) shows the equilibrium values of oil adsorbed per unit weight of adsorbent qe versus the liquid phase sorbate concentration at equilibrium ce. it can be seen that the adsorption capacity increased until an equilibrium concentration was obtained. this confirms a favorable adsorption system. fig.2 :equilibrium adsorption of oil on activated carbon and zeolite at 30°c with 2 grams of adsorbent and a mixing time of 20 min. there are many theories relating to adsorption equilibrium [7],[8],[9].the isotherms of the oil adsorption by activated carbon and zeolite were represented by applying the freundlich and langmuir adsorption models. langmuir isotherm the langmuir isotherm theory assumes monolayer coverage of adsorbate over a homogenous adsorbent surface. therefore, at equilibrium, upon reaching a saturation point, no further adsorption can occur. in equation (5), qo is the maximum amount of adsorption corresponding to complete monolayer coverage and kl is the langmuir constant . el eo e ck cq q   ……….. (5) the linea r expression of eq. (5) can be written in the following form: 0 1 2 3 4 5 6 7 8 9 10 0 5000 10000 15000 qe mg/g ce (ppm) activate d carbon zeolite sawsan a. m. mohammed, ibtihage faisal and maha m. alwan vol.12 no.1 (march 2011) e oole e c qqkq c          11 ……… (6) a linearized plot of ( ee qc ) vs. ce is shown in fig. (3). it was found that in fig. (3), the langmuir isotherm did not fit the data with a correlation coefficient much lower than 1.0 throughout the experimental range of oil concentrations studied for both activated carbon and zeolite. the langmuir equation is applicable to homogeneous sorption where the sorption of each molecule has equal sorption activation energy. fig.3: linearized langmuir isotherm for oil adsorption by activated carbon and zeolite. freundlich isotherm the freundlich expression is an exponential equation and therefore, assumes that the amount of adsorbate adsorbed increases infinitely with an increase in concentration. fn efe ckq 1  ………. (7) in this equation, kf and 1/nf are the freundlich constants. this expression is characterized by the heterogeneity factor, 1/nf, and thus the freundlich isotherm may be used to describe heterogeneous system [10],[11].to determine the constant kf and 1/nf, the linear form of the equation as shown below may be used to plot ln(qe) against ln (ce) as: effe cnkq ln1lnln  ……… (8) fig. (4) shows the freundlich plot and gives a straight line. it is clearly shown that the freundlich isotherm model fits the analyzed data well for both adsorbents with correlation coefficient (r 2 ) values of 0.9601 for activated carbon and 0.8949 for zeolite. the isotherm for activated carbon is represented as: 988.03 109.1 ee cq   ………. (9) the freundlich model assumes that the uptake of any adsorbate occurs on a heterogeneous surface by multilayer adsorption and that the amount of adsorbate adsorbed increases infinitely with an increase in concentration. the heterogeneity factor 1/nf was 0.988 and nf value was 1.012. it is known that when the nf value is greater than 1.0, conditions are favorable to adsorption. freundlich isotherm for zeolite is represented as: 957.04 108.3 ee cq   ………. (10) hence it is clearly proved that oil adsorption by activated carbon and zeolite agrees well with the freundlich adsorption model. r² = 0.193 3000 3500 4000 4500 0 10000 20000 c e /q ce (ppm) zeolite r² = 0.250 400 500 600 700 0 2000 4000 6000 8000 c e /q ce(ppm) activated carbon oily wastewater treatment using expanded beds of activated carbon and zeolite vol.12 no.1 (march 2011) fig.4: linearized freundlich isotherm for oil adsorption by activated carbon and zeolite. table (2): freundlich and langmuir parameters of adsorption isotherms for the removal of oil by activated carbon and zeolite. freundlich isotherm langmuir isotherm adsorbent nf (-) kf (g/l) 1/nf correlation coeff. (r 2 ) qo(mg/g) kl(g/l) correlation coeff. (r 2 ) activated carbon 1.012 1.9*10 -3 0.9617 55.25 3.6*10 -5 0.2504 zeolite 1.04 3.8*10 -4 0.8949 19.01 1.5*10 -5 0.1934 effect of mixing time in the adsorption systems contact time plays an important role. in order to study the kinetics and dynamics of adsorption of oil by activated carbon and zeolite, the adsorption experiments were conducted and the extent of oil removal was obtained at various contact time ranged 5-25 min at fixed oil concentration ( 24000 ppm) with a fixed dosage of adsorbent (2 g) and 150 rpm. the influence of contact time on residual oil removal using activated carbon and zeolite as adsorbents is shown in fig.(5) . by increasing contact time, the residual oil molecules have a longer residence time for adsorption on the adsorbent surface area. at equilibrium, the surface of the adsorbent was covered with oil molecules; therefore a longer mixing time does not increase residual oil removal from y = 0.988x -2.717 r² = 0.961 y = 0.957x -3.410 r² = 0.894 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1 1.2 3 3.5 4 4.5 5 lo g q e log ce activated carbon zeolite sawsan a. m. mohammed, ibtihage faisal and maha m. alwan vol.12 no.1 (march 2011) wastewater. fig.(5) shows that when the mixing time was increased from 20 min. to 25 min., the reduction value of residual oil was only increased by less than 1000 ppm for activated carbon while the value of residual oil remains unchanged at 10000 ppm for zeoilte. this indicates that zeoilte became saturated faster than activated carbon. fig.5: the influence of mixing time on the sorption of residual oil with 2g of adsorbent at 30°c and 150 rpm. effect of adsorbent loading different quantities of adsorbent were added to oily water samples ranged 2-8 g with initial concentration of oil 20000 ppm and contact time 20 min. it was found that as the dosage of adsorbent was increased, the percentage of residual oil removal also increased, as shown in fig.(6). adsorption is a surface related phenomenon, at equilibrium most of the oil molecules were adsorbed on the surface and in the intermolecular pores of the adsorbent. it takes about 8 g of activated carbon to reduce the initial residual oil concentration of 20000 ppm to a final concentration of zero ppm while the final concentration is 10000 ppm for the same weight of zeolite. similar observation has been reported by ahmed et al [1]. fig. 6: effect of dosage of adsorbent on the reduction of residual oil at a mixing time of 20 min. at 30°c. expanded bed experiments break-through curve successful design of a column adsorption process requires prediction of the concentration-time profile or breakthrough curve for the effluent. effect of adsorbent type based on fig. (7), activated carbon performed better adsorption properties than zeolite in the removal of oil. activated carbon differs in their adsorption efficiencies. it is very important to know the nature of pollutants to be removed from contaminated 0 5000 10000 15000 20000 25000 30000 0 10 20 30 r e si d u a l o il c o n ce n tr a ti o n (p p m ) time (min) activated carbon zeolite 0 2000 4000 6000 8000 10000 12000 14000 16000 18000 0 5 10 r e si d u a l o il c o n ce n tr a ti o n ( p p m ) wt. of absorbant (g) activated carbon zeolite oily wastewater treatment using expanded beds of activated carbon and zeolite vol.12 no.1 (march 2011) media before deciding what a specific sorbent to select. in many applications, an activated carbon exhibits a sufficient capacity towards existing, especially organic water pollutants, however zeolite may adsorb some metals and ammonia more selectively [12]. fig. 7: effect of adsorbent type and the amount of coagulant salt on breakthrough curve (c0=24000 ppm, q=50 l/hr). effect of the amount of coagulant salt data for the ratio of oil concentration at the outlet of the bed and the concentration of the inlet stream (c/c0) as a function of time, for beds with varying amounts of coagulant salt are shown in fig.(7). it is observed that the addition of higher amount of calcium sulphate is essential to achieve larger oil removal. the dissolved salt ions compress the electric double layer around droplets, neutralize repulsive forces among them and between droplets and activated carbon particles and, hence, enhance coalescence of oil droplets. moreover, the lack of electrostatic repulsion improves the physical adsorption of the oil droplets on the carbon surface. the oil droplet size is increased and its charge neutralized, so that the disperse phase can be retained in the filter media interstices. furthermore, some authors have pointed out that calcium salts activates the sorption sites of sorbent materials in the removal of different unwanted materials from water [13] , [14]. the richardson-zaki exponent constant the effects of superficial velocity ( 0 v ) of the feed stream on the bed expansion ( 0 hh ) were measured. the bed expansion factor was limited below 4 as recommended by reichent et al.[15], for proper performance of expanded beds. fig.8:effect of the superficial velocity of fluid on the bed expansion. although coulson et al.[16], provided  0s  , values for spherical particles of various sizes,   0s  value for the bed was measured as 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 20 40 60 c /c 0 t (min) activated carbon zeolite activated carbon +2g caso4.2h2o activated carbon +4g caso4.2h2o 0 0.5 1 1.5 2 2.5 3 3.5 0 0.01 0.02 0.03 0.04 h/h0 v0(m/s) activated carbon zeolite sawsan a. m. mohammed, ibtihage faisal and maha m. alwan vol.12 no.1 (march 2011) follows. in the column the particles were settled in distilled water. the water contained inside the void fraction of the sedimented bed was drained off. the volume of the drained water was measured and divided by that of the total sedimented bed to determine the void fraction, of the bed. finally,   0s  values determined by 1- were 0.55 for activated carbon and 0.75 for zeolite [17]. fig.(9) shows the richardson – zaki plot for the experimental data. the line in the figure have a slope (n value) of 3.27 and the terminal velocity is 0.063 m/s for activated carbon and (n) value of 1.311 and the terminal velocity is 0.017 m/s for zeolite. fig.9: richardson-zaki plot for the bed expansion the exponent n is a function of terminal particle re. based on bed expansion data, the equation recommended for the range of terminal particle re used is [18],[19]: 1.0 re45.4  n for 1< re <500 ……... (11) the validity of richardsonzaki equation has been confirmed with the experimental data for activated carbon better than for zeolite (ncalc.= 3.08 for carbon and ncalc.= 4.88 for zeolite). this allow further investigation of the hydrodynamics for zeolit system such as to predict segregation phenomena in the expanded bed. fig. (10) demonstrates that the calculated bed expansion, ( 0 hh ) cal using eqs. (3) and (1) are in good agreement with experimentally measured values of the bed expansion ( 0 hh ) exp for activated carbon more than that for zeolite. fig.10: comparison of bed expansion calculated (h/h0) cal, with those of experimentally determined values, (h/h0) exp. conclusions the following conclusions are drawn from the above-discussed results: 1. the adsorption process of oil on activated carbon and zeolite fits well with freundlich isotherm. 2. the amount of oil adsorbed increased with the increase in contact time. at equilibrium, the surface of the adsorbent was covered with oil y = 3.266x -1.206 r² = 0.982 y = 1.311x -1.762 r² = 0.976 -3 -2.8 -2.6 -2.4 -2.2 -2 -1.8 -1.6 -1.4 -1.2 -1 -0.36 -0.31 -0.26 -0.21 -0.16 -0.11 -0.06 -0.01 lo g v 0 log(1-фs) activated carbon zeolit 1 1.5 2 2.5 3 3.5 4 1 1.5 2 2.5 3 3.5 (h /h 0 ) ca l. (h/h0)exp activated carbon zeolite oily wastewater treatment using expanded beds of activated carbon and zeolite vol.12 no.1 (march 2011) 3. molecules; therefore a longer mixing time does not increase residual oil removal from wastewater. 4. it was found that as the dosage of adsorbent was increased, the percentage of residual oil removal also increased. for expanded bed experiments 1. activated carbon performed better adsorption properties than zeolite in the removal of oil 2. it is observed that the addition of higher amount of calcium sulphate is essential to achieve larger oil removal. the break point time is obtained earlier without the addition of the coagulant. 3. the validity of richardson-zaki equation has been confirmed with the experimental data for activated carbon better than for zeolite. nomenclature c the concentration of oil at time t (ppm) c0the concentration of oil at time zero (ppm) ce equilibrium concentration of oil (ppm) p d particle diameter (m) g acceleration of gravity (m/s 2 ) h height of the expanded bed (m) 0 h height of bed at zero flow stream (m) kf freundlich constant(g/l) 1/nf kl langmuir constant (g/l) n richardsonzaki exponent constant (-) 1/nf heterogeneity factor qe amount of oil adsorbed per unit weight of adsorbent (mg/ g) q0 maximum amount of adsorption (mg/g) 0 v superficial velocity (m/s) mf v particle minimum fluidization velocity (m/s) t v terminal settling velocity (m/s) re particle reynolds number (-) greek letters l  density of fluid (kg/m 3 ) s  density of particle (kg/m 3 ) l  dynamic viscosity of fluid (kg/m.s) s  solid fraction of the expanded bed (-) 0  solid fraction of the bed at zero flow stream (-)  void fraction of the bed (-) references 1. ahmed a.l., bhatia s., ibrahim n. and sumathi s., 2005"adsorption of residual oil from palm oil mill effluent using rubber powder", brazilian j. chem. eng, v.22, no.3, pp.371-379. 2. alther g. r., 1995"organically modified clay removal oil from water", waste management, v.15, no.8, pp.622-628. sawsan a. m. mohammed, ibtihage faisal and maha m. alwan vol.12 no.1 (march 2011) 3. quevedo j.a., patel g. and pfeffer r.,2009"removal of oil from water by inverse fluidization of aerogels", ind. eng. chem. res., 48, pp 191-201. 4. richardson j.f. and zaki w.n., 1954,"sedimentation and fluidization", trans. inst. chem. eng., 32, pp.35-52. 5. wen c.y., and yu y.h., 1966,"mechanics of fluidization", chem. eng. progr. symp. ser., v.62, pp.100-111. 6. ramaswamy,e.,sirinivasakaan, c. and balasubramaniam, n., 2008,”bed expansion characteristics of liquidsolid fluidized bed with internals”, modern applied science, 2(2), pp 8492. 7. adamson a.w., 1960, physical chemistry of surface, inter. science publ. inc., new york, pp. 777. 8. alessandra f. freitas, bruno b. frança, marisa f. mendes and gerson l.v. coelho, 2005” thermodynamic studies of acetic acid adsorption onto activated carbon” 2nd mercosur congress on chemical engineering ,4th mercosur congress on process systems engineering, brazil. 9. alihosseini a., taghikhani v., safekordi a.a. and bastani d., 2010,"equilibrium sorption of crude oil by expanded perlite using different adsorption isotherms at 298.15 k", int.j environ. sci. tech., v.7,no.3, pp. 591-598. 10. moon h. and lee w.k., 1983,"intraparticle diffusion in liquid phase adsorption of phenols with activated carbon in a finite batch absorber", j. coll. interf. sci., v.96, no. 1, pp. 462-473. 11. al-duri b. and mckay g., 1988,"basic dye adsorption on carbon using a solid phase model", chem. eng. j.v.38, no.1, pp.23-31. 12. al-haddad a. chmielewská e. and al-radwan s., 2007," a brief comparable lab examination for oil refinery wastewater treatment using the zeolitic and carbonaceous adsorbents" petroleum & coal v.49 no.1, pp.21-26. 13. shukla a., zhang y.h. and margrave s.s.,2002,"the role of sawdust in the removal of unwanted materials from water", j. hazard. mater. b.95, pp 137-152. 14. cambiella a., ortea e., rios g., coca j., 2006,"treatment of oil in water emulsions: performance of a sawdust bed filter", j. hazardous materials, b131, pp.195-199. 15. reichent, u., knieps, e., slusarczyk, h., kular, n. r. and thommes, j., 2001, “isolation of a recombinant format dehydrogenase by pseudo affinity expanded bed adsorption”, j. biochem. biophys. methods, 49, pp 533. 16. coulson j.m., richardson j.f.,backhurst j.r. and harker j.h., 1991,"chemical engineering" vol.2, 4 th edn. pergamon press, oxford. 17. chae y.r., yoon y.j. and ryu k.g., 2004,"development of modified stokes expression to model the behavior of expanded beds containing polydisperse resins for protein adsorption", korean j. chem. eng., v.21, no.5, pp 999-1002. 18. yang j. and renken a.,2003,"a generalized correlation for equilibrium of forces in liquid-solid fluidized beds", chem. eng. j., 92, pp 7-14 19. karamanev d.g. and nikolov l.n., 1992,"bed expansion of liquid-solid inverse fluidization", aiche j, v.38,no.12, pp1916-1922. oily wastewater treatment using expanded beds of activated carbon and zeolite vol.12 no.1 (march 2011) معالجة مياه التصريف السيتية باستخذام اعمذة االمتساز المتمذدة مه الكاربون المنشط والسيواليت :الخالصة حٌ في هزٓ اىذساست ٍعاىجت ٍيآ اىخصشيف اىضيخيت بىاسطت االٍخضاص عيى اىناسبىُ اىَْشط واىضيىاليج واسخخذٍج طشيقت حيث اسخخذٍج االوىى اليجاد ٍعذه وعالقت االٍخضاص ىيضيج عيى . االٍخضاص رو اىذفعاث وباسخخذاً االعَذة اىَخَذدة اىَخغيشاث اىخي حٌ دساسخها . اىناسبىُ اىَْشط واىضيىاليج بيَْا اسخخذٍج اىثاّيت اليجاد مفاءة عَييت اىَعاٍيت وايجاد االداء صيج )ىضيىث اىْباحيت هسيىك االٍخضاص في هزٓ اىذساست ، حٌ فحص. هي حشميض اىَادة اىََخضة واىضٍِ ومَيت اىَادة اىَاصة (مبشيخاث اىناىسيىً)مَيت اىَيح و ة اىََخضمَيت اىَادةعيى اىنشبىُ اىَْشط واىضيىاليج مذاىت ىيخشميض ، و (اىزسة ٍعادىت فشويْذىش ووجذ أُ. وىْنَيش فشوّذىيخش حٌ حَثيو اىْخائج باسخخذاً عالقاث االٍخضاص ثابخت دسجت اىحشاسة .ضافاىٌ . اىضيىاليجو اىنشبىُ اىَْشط عيى حضاص عَييت االًحْطبق عيى حٌ . اُ مَيت اىضيج اىََخض حضداد ٍع صيادة صٍِ اىخَاط ومزىل وجذ اُ صيادة اىَادة اىَاصة سخضيذ ٍِ ّسبت اصاىت اىضيج .ايضا دساست حاثيش ّىع اىَادة اىَاصة اىَسخخذٍت عيى ٍْحْي اىَقاوٍت صامي بيِ اىسشعت اىفشاغيت واىجضء اىبيْي ىيعَىد في –حٌ حَثيو حصشف االعَذة اىَخَذدة باسخخذاً ٍعادىت سيخشاسدسِ .حذود ٍعخذىت ٍِ سقٌ سيْىىذص sawsan a. m. mohammed, ibtihage faisal and maha m. alwan vol.12 no.1 (march 2011) available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.21 no.2 (june 2020) 47 – 56 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: douaa hussein ali, email: olawissam86@gmail.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. studying the rheological properties of non-newtonian fluids under the effect of temperature using different chemical additives douaa hussein ali and muhannad a.r. mohammed chemical engineering department – college of engineeringuniversity of al-nahrainiraq abstract this research studies the rheological properties ( plastic viscosity, yield point and apparent viscosity) of non-newtonian fluids under the effect of temperature using different chemical additives, such as (xanthan gum (xc-polymer), carboxyl methyl cellulose ( high and low viscosity ) ,polyacrylamide, polyvinyl alcohol, starch, quebracho and chrome lignosulfonate). the samples were prepared by mixing 22.5g of bentonite with 350 ml of water and adding the additives in four different concentrations (3, 6, 9 , 13) g by using hamilton beach mixer. the rheological properties of prepared samples were measured by using fan viscometer model 8speeds. all the samples were subjected to bingham plastic model. the temperature rang studied is from 50 to 200 °f. the results shows that the rheological properties (plastic viscosity, apparent viscosity and yield point) decreased as temperature increased for all prepared samples of non-newtonian fluids. keywords: rheological properties, non-newtonian fluids, bingham plastic model received on 28/11/2019, accepted on 20/01/2020, published on 30/06/2020 https://doi.org/10.31699/ijcpe.2020.2.6 1introduction the fluid is defined as a substance that is constantly distorted under the influence of external force. in another meaning, the fluid can flow and does not have consolidated three as dimensional defaults. the ideal fluid can be defined the fluid that has no friction. thus the forces acting on any internal section of the fluid are purely pressure forces, even during motion [1]. in a real fluid, shearing (tangential) and extensional forces always come into play whenever motion takes place, thus given rise to fluid friction, because these forces oppose the movement of one particle relative to another. these friction forces are due to a property of the fluid called viscosity. the friction forces in fluid flow result from the cohesion and momentum interchange between the molecules in the fluid. the viscosity of most of the fluids we encounter in everyday life is independent of the applied external force. there is, however, a large class of fluids with a fundamental different behavior. this happens, for example, whenever the fluid contains polymer macromolecules, even if they are present in minute concentrations. two properties are responsible for this behavior. on one hand, polymers change the viscosity of the suspension by changing their shape depending on the type of flow. on the other hand, polymer have long relaxation times associated with them, which are on same order as the time scale of the flow, and allow the polymers to respond to the flow with a corresponding time delay. other complex systems consisting of several phases, such as suspensions or emulsions and most of the biological fluids, behave in a similar manner [1]. diego et al. studied the rheological properties of carboxy methyl cellulose. the results exhibited that the aqueous solutions of cmc exhibited a non-newtonian flow behavior to reduce shear. the effect of the polymer concentration is an increase in the apparent viscosity. when the temperature raises a decrease in apparent viscosity and shear thinning occurred [2]. khaled et al. studied the non-newtonian fluids it contains different types of salt (nacl and kcl) in different concentrations. the results of this study led to the conclusion that when the temperature increased the rheological properties of non-newtonian fluids were decreased [3]. mohd et al. studied the rheological behavior of polyacrylamide solutions at different temperatures by rheometry. when surfactants were added, the viscosity of polyacrylamide solution increased and when the temperature increased the rheological properties of nonnewtonian fluids were decreased. [4] vassilios et al. studied the effect of temperature on the rheological behavior of bentonite water dispersion. high temperature increased shear stress at low shear rates while the effect was much smaller in higher shear rates. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:olawissam86@gmail.com http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2020.2.6 d. h. ali and m. a.r. mohammed / iraqi journal of chemical and petroleum engineering 21,2 (2020) 47 56 48 the bingham yield stress, from the low shear rate data, increased linearly with temperature, while plastic viscosity decreased with temperature, in a manner very similar to the decrease of water viscosity with temperature [5]. the aim of present work is as follow: studying the rheological properties of non-newtonian fluids under the addition of different chemical additives. it is also aimed to study the effect of temperature on the rheological properties of the non-newtonian fluids, and finding the best additive that made a non-newtonian fluid stable with temperature. 2basic rheological concepts the domain of rheology is the field of distortion and the flux of substance, by conducting a specific mensuration on the liquid. it is conceivable to limit how the flow of liquid under a set of states, encompass of temperature, pressure and the rate of shear [6]. 2.1 viscosity of a fluid the viscosity is defined as the proportion of shear stress (τ) to shear rate (γ). [7] mathematical relation is: μ = τ γ (1) the viscosity units can be described as ( newton . seconds / m 2 ), ( pascal seconds) or poise (dyne seconds / cm 2 ). 2.2. shear stress the shear stress (τ) is defined as the force wanted to maintain the motion of a special kind of fluid inflow across the region [8]. mathematical relation is: τ = f a (2) where: 𝜏 is shear stress in unit (n/m2), (pascal) or (dynes/cm2), f is the force in unit newton, a is the area of surface subject to stress in unit (m2). 2.3. shear rate the rate of shear (𝛾) is defined as the ratio of the average of variation in velocity while a layer of fluid pass into an adjacent layer, the space separating of them. it was expressed in sec -1 (reciprocal seconds) [9]. 2.4. plastic viscosity the plastic viscosity is the tendency of the stress of shear / rates of shear line at the highest the yield point. pv appears the viscosity of the fluid while generalized to an infinite rate of shear based on the mathematics of the bingham model [10]. the mathematics equation of the bingham plastic fluid as follows: τ = yp + pv (γ) (3) mathematical relation is: 𝑃𝑉= θ600−θ300 where: pv is plastic viscosity in unit cp, θ600 is shear stress at 600 rpm shear rate, in lb. /100 ft 2. θ300 is shear stress at 300 rpm shear rate, in lb. /100 ft 2 . 2.5. yield point the yield point (yp) is a second variable of bingham model and it is a measurement of electrochemical intensity or attractive intensity in the liquid. this part of the flowing impedance can be domination by appropriate chemical remediation. [11] mathematical relation is: yp = θ300 − pv (4) where: yp is yield point in unit (lb. /100 ft 2 ) or (pa.s) pv is the plastic viscosity in unit cp θ300 is shear stress at 300 rpm shear rate, in lb. /100 ft 2 . 2.6 apparent viscosity the apparent viscosity is fluid viscosity determined by the shear rate given by the api. in the rheology of bingham plastic model, av represents half the dial reading at 600 rpm (i.e. the shear rate is equal to 1022 sec 1 ) using a viscometer [12]. mathematical relation is: av = θ600 2 (5) where: av is apparent viscosity in unit cp θ600 is shear stress at 600 rpm shear rate, in lb. /100 ft 2 . 3non newtonian fluid behavior for a nonnewtonian fluid, the flow curve (shear stress versus shear rate) is not arranged in a straight line. wherever apparent viscosity (shear stress /shear rate) is not fixed at certain temperature and pressure but depends on flow states like flow geometry, shear rate and so on. 3.1. time-independent behavior fluids of time-independent type whose flow properties are independent of the duration of shearing may be described in simple shear by a rheological equation of the form: τyx = f(γyx )̇ this equation means that the rate of shear at any point within the sheared fluid is determined solely by the current value of the shear stress at that point, or vice versa. depending upon the form of equation, these fluids may be further subdivided into three different types: [13] d. h. ali and m. a.r. mohammed / iraqi journal of chemical and petroleum engineering 21,2 (2020) 47 56 49 1. shear-thinning or pseudoplastics 2. visco-plastics 3. shear-thickening or dilatant 3.2. time-dependent behavior ideally, time-dependent materials are considered to be inelastic with viscosity function which depends on time. the response of the substance to stress is instantaneous and the time, dependent behavior is due to change in the structure of the material itself. in contrast, time effects found in viscoelastic substances arise because the response of stress to applied strain is not instantaneous and not related with a structural variation in the materials. also, the time scale of thixotropy may be quite than the time scale of associated with viscoelasticity: the most dramatic effects are usually observed in situations involving short process time. note too, that real materials may be time-dependent and viscoelastic. [14] 3.3 effect of temperature on the rheological properties the temperature effects on the rheological properties (plastic viscosity, yield point and apparent viscosity) of non-newtonian fluids. the rheological properties (plastic viscosity, yield point and apparent viscosity) of nonnewtonian fluids were decreased as temperature increased. increasing temperature causes decreased in viscosity of the continuous phase of polymer fluids, which results in the reduction of plastic viscosity values through decreasing the friction forces between particles in the sample. also, increasing temperature causes decreasing in the attraction forces between particles in the polymer fluid due to the increase in distance between particles causing a reduction interaction between claypolymer colloids. [15] 4experimental work 4.1. materials all the polymers used in this work were as follows: bentonite was supplied from qingdao easthony inc. china. xanthan gum (xcpolymer) was supplied from fengchen group, qingdao, china. carboxy methyl cellulose (cmc) high viscosity is supplied from dalian chem. imp. and exp. group co., ltd. china. carboxy methyl cellulose (cmc) low viscosity was supplied from denkim denizli kimya a.s., turkey. polyacrylamide (pam) was supplied from henan province. henan di luo environmental protection technology co., ltd., china, poly vinyl alcohol was supplied from elgin, kolkata. peekay agencies private limited, india. starch was supplied from amstel products b.v. company, netherlands. chrome lignosulfonate (cls) and quebracho were supplied from laboratories of petroleum engineering department, college of engineering, university of baghdad. 4.2. preparation of samples 1four concentrations of (xanthan gum (xc-polymer), carboxy methyl cellulose ( high and low viscosity ) ,polyacrylamide, polyvinyl alcohol, starch, quebracho and chrome lignosulfonate) are weighed which are (3,6,9,13) grams. also weighed four concentrations of bentonite (22.5 grams) with four cups each one contains water (350 ml). 2by using hamilton beach mixer and cup, the sample was prepared by adding the first concentration of additives to the clay suspension mixture of bentonite and water. 3continue mixing until the polymer is dissolved in the clay suspension and then prepare the second, third, and fourth concentrations of additives in the same way. 4the prepared solutions was poured into a properly labeled bottle and sealed. 5then the prepared solutions were kept and save at room temperature for 24 hours prior to conducting the rheological measurements. 4.3. experimental procedure the procedure for measuring the rheological properties of all prepared samples, using viscometer 800-8 speeds as shown in fig. 1 is as follows: clean the device thoroughly before starting. it is necessary to clean the bob column and the rotor also before submerging the rotor and bob in the samples whose rheological properties should be measured. fill the cup to the scribed line with calibration fluid and place it on the viscometer stage. move the stage upward until the fluid level is to the fill line on the sleeve. the instrument stage was so high that the rotor was immersed at the appropriate immersion depth. never immerse the sleeve in fluids above the fill line. the speed of the machine turned to 600 rpm and recorded the disc reading. after recording, the speed of the device should be stirred for a short time for 2-3 minutes to prevent the formation of the sample and repeat the speed of the device at 300 rpm and record the reading of the request as well. repeat the previous step and recorded the dial reading at speeds of 200, 100, 60, 30, 6 and 3 rpm. [16] fig. 1. fann vgviscometer model 800 d. h. ali and m. a.r. mohammed / iraqi journal of chemical and petroleum engineering 21,2 (2020) 47 56 50 for the purpose of measuring the rheological properties under the influence of heat, the following procedure should be followed: the heating device (heater) must be turned on for a period before use. firstly, measuring the rheological properties of the sample at room temperature which is reaches50 ℉, using speed viscometer model 800-8.then the cup is taken that contains the sample to be heated using the thermometer to measure temperature with continuous stirring to prevent the occurrence of a conglomeration in the sample, the sample must be cover by the appropriate cap to prevent the evaporation of the sample during heating. when the sample temperature reaches100 ℉, the cup should be taken and placed in the rheological device (speed viscometer model 800-8). take the sample speed readings and record them. repeat above steps until temperatures reaches 150 and200 ℉ [16]. 5results and discussion the results shows that the plastic viscosity of the nonnewtonian fluids at 22.5g of bentonite at various concentrations with additives (xc-polymer, cmc low viscosity, cmc high viscosity, polyacrylamide, polyvinyl alcohol, starch, chrome lignosulfonate and quebracho) were decreased by increasing the temperature. increasing temperature causes decreased in viscosity of the continuous phase of polymer fluids, which results in the reduction of plastic viscosity values through decreasing the friction forces between particles in the sample. also, increasing temperature causes decreasing in the attraction forces between particles in the polymer fluid, this is due to the increase in distance between particles causing a reduction interaction between clay-polymer colloids [15]. the results showed that the decrease in plastic viscosity begins after the temperature of 50°f and gradually increases at a temperature of 100 °f and 150 °f until it reaches 200 °f for all four concentrations prepared. as shown in fig. 2 to fig. 6. it can also notice that the effect of temperature is often higher at the concentration of 13 grams and less at 3 grams. fig. 2. the effect of temperature on the plastic viscosity of the fluid when adding xc-polymer fig. 3. the effect of temperature on the plastic viscosity of the fluid when adding cmc l.v fig. 4. the effect of temperature on the plastic viscosity of the fluid when adding cmc h.v fig. 5. the effect of temperature on the plastic viscosity of the fluid when adding polyacrylamide fig. 6. the effect of temperature on the plastic viscosity of the fluid when adding polyvinyl alcohol d. h. ali and m. a.r. mohammed / iraqi journal of chemical and petroleum engineering 21,2 (2020) 47 56 51 when heating the prepared samples containing the addition of starch, it was observed that there is no heat effect on the starch or little effect. the reason is that during heating, starch molecules may accumulate in the form of lump or aggregate starch molecules. as shown in fig. 7. thus, the effect of temperature on plastic viscosity is minimal or constant. fig. 7. the effect of temperature on the plastic viscosity of the fluid when adding starch the results can show that the effect of (chrome lignosulfonate and quebracho) on plastic viscosity was decreased by increasing the temperature of additives to non-newtonian fluids at (22.5) grams of bentonite at four different concentrations. as shown in fig. 8 and fig. 9. fig. 8. the effect of temperature on the plastic viscosity of the fluid when adding cl fig. 9. the effect of temperature on the plastic viscosity of the fluid when adding quebracho this is because of all hydroxides react with clay minerals at temperatures above about 200°f (94°c). with low alkalinity fluids, such as those treated with quebracho tannin or lignosulfonate, the effect on their rheological properties is not significant, except to the extent that the loss of alkalinity lessens the effectiveness of the thinner. but with highly alkaline fluids the effect may be severe, depending on the temperature and the species of metal ion of the hydroxide. the results shows that the yield point of the nonnewtonian fluids at 22.5g of bentonite at various concentrations with additives (xc-polymer, cmc low viscosity, cmc high viscosity, polyacrylamide and polyvinyl alcohol) were decreased with increasing the temperature. temperature causes reduction in the viscosity of non-newtonian fluid and in the friction forces between the solid particles in the non-newtonian fluid mixtures due to increase the space between particles, which will result in a noticeable decrease in yield point of non-newtonian fluid samples [16]. the results showed that the decrease in yield point begins after the temperature of 50°f and gradually increases at a temperature of 100 °f and 150 °f until it reaches 200 °f for all four concentrations prepared. as shown in fig. 10 to fig. 14. it can also noticed that the effect of temperature is often higher at the concentration of 13 grams and less at 3 grams. fig. 10. the effect of temperature on the yield point of the fluid when adding xc-polymer fig. 11. the effect of temperature on the yield point of the fluid when adding cmc l.v d. h. ali and m. a.r. mohammed / iraqi journal of chemical and petroleum engineering 21,2 (2020) 47 56 52 fig. 12. the effect of temperature on the yield point of the fluid when adding cmc h.v fig. 13. the effect of temperature on the yield point of the fluid when adding polyacrylamide fig. 14. the effect of temperature on the yield point of the fluid when adding polyvinyl alcohol when heating the prepared samples containing the addition of starch, it was observed that there is no heat effect on the starch or little effect. the reason is that during heating, starch molecules may accumulate in the form of lump or aggregate starch molecules. as shown in fig. 15. thus, the effect of temperature on yield point is minimal or constant. fig. 15. the effect of temperature on the yield point of the fluid when adding starch the results can show that the effect of (chrome lignosulfonate and quebracho) on yield point was decreased by increasing the temperature of additives to non-newtonian fluids at (22.5) grams of bentonite at four different concentrations. as shown in fig. 16 and fig. 17. this is because of all hydroxides react with clay minerals at temperatures above about 200°f (94°c). with low alkalinity fluids, such as those treated with quebracho tannin or lignosulfonate, the effect on their rheological properties is not significant, except to the extent that the loss of alkalinity lessens the effectiveness of the thinner. but with highly alkaline fluids the effect may be severe, depending on the temperature and the species of metal ion of the hydroxide. fig. 16. the effect of temperature on the yield point of the fluid when adding chrome lignosulfonate fig. 17. the effect of temperature on the yield point of the fluid when adding quebracho d. h. ali and m. a.r. mohammed / iraqi journal of chemical and petroleum engineering 21,2 (2020) 47 56 53 the results shows that the apparent viscosity of the nonnewtonian fluids at 22.5g of bentonite at various concentrations with additives (xc-polymer, cmc low viscosity, cmc high viscosity, polyacrylamide, polyvinyl alcohol, starch, chrome lignosulfonate and quebracho) were decreased by increasing the temperature. apparent viscosity decreases with increasing temperature; this is due to the increasing in distance between clay-polymer colloids as temperature increases causes low attraction forces. also, it can be observed that on gel structure is formed as temperature increased [16]. the results showed that the decrease in apparent viscosity begins after the temperature of 50°f and gradually increases at a temperature of 100 °f and 150 °f until it reaches 200 °f for all four concentrations prepared. as shown in fig. 18 to fig. 25. it can also notice that the effect of temperature is often higher at the concentration of 13 grams and less at 3 grams. fig. 18. the effect of temperature on the apparent viscosity of the fluid when adding xc-polymer fig. 19. the effect of temperature on the apparent viscosity of the fluid when adding cmc l.v fig. 20. the effect of temperature on the apparent viscosity of the fluid when adding cmc h.v fig. 21. the effect of temperature on the apparent viscosity of the fluid when adding polyacrylamide fig. 22. the effect of temperature on the apparent viscosity of the fluid when adding polyvinyl alcohol fig. 23. the effect of temperature on the apparent viscosity of the fluid when adding starch d. h. ali and m. a.r. mohammed / iraqi journal of chemical and petroleum engineering 21,2 (2020) 47 56 54 fig. 24. the effect of temperature on the apparent viscosity of the fluid when adding cl fig. 25. the effect of temperature on the apparent viscosity of the fluid when adding quebracho 6conclusions the plastic viscosity of the non-newtonian fluids at 22.5g of bentonite at various concentrations with additives (xc-polymer, cmc low viscosity, cmc high viscosity, polyacrylamide, polyvinyl alcohol, starch, chrome lignosulfonate and quebracho) were decreased by increasing the temperature. also, it was found that the yield point of the nonnewtonian fluids at 22.5g of bentonite at various concentrations with additives (xc-polymer, cmc low viscosity, cmc high viscosity, polyacrylamide and polyvinyl alcohol) were decreased with increasing the temperature. finally, it was concluded that the apparent viscosity of the non-newtonian fluids at 22.5g of bentonite at various concentrations with additives (xc-polymer, cmc low viscosity, cmc high viscosity, polyacrylamide, polyvinyl alcohol, starch, chrome lignosulfonate and quebracho) were decreased by increasing the temperature. the rheological properties ( plastic viscosity, apparent viscosity and yield point) were decreased begins after the temperature of 50°f and gradually increases at a temperature of 100 °f and 150 °f until it reaches 200 °f for all four concentrations prepared. as shown in fig. (18) to (25). it can also notice that the effect of temperature is often higher at the concentration of 13 grams and less at 3 grams. references [1] brujan, e. a., “cavitation in non-newtonian fluids with biomedical and bioengineering applications”. springer heidelberg dordrecht london new york isbn 13:978-3-642-15343-3, 2010. [2] gómez-dı́az, diego, and josé m. navaza. "rheology of aqueous solutions of food additives: effect of concentration, temperature and blending." journal of food engineering 56.4 (2003): 387-392. [3] hassiba k. j. and amani m., “the effect of salinity on the rheological properties of water based under high pressures and high temperatures for drilling offshore and deep wells”. published by canadian center of science and education. earth science research; vol. 2, no. 1, 2012. [4] khan m. b., “rheological behavior of polyacrylamide solution in the presence of cationic gemini surfactants/conventional surfactants”. asia-pacific journal of chemical engineering. vol. 12, pages 671678, 2017. [5] vryzas z., kelessidis v. c., nalbantian l., zaspalis v., gerogiorgis d. i. and wubulikasimu y., “effect of temperature on the rheological properties of neat aqueous wyoming sodium bentonite dispersions”. journal of applied clay science. vol. 136, pages 2636, 2017. [6] adewale f. j., lucky a. p., oluwabunmi a. p. and boluwaji e. f., “selecting the most appropriate model for rheological characterization of synthetic based drilling mud”. international journal of applied engineering research issn 0973-4562 volume 12.number 18. pp. 7614-7629, 2017. [7] mohammed, muhanned ar, and areej jasim mohammed. "effect of type and concentration of different water soluble polymer solutions on rheological properties." al-nahrain journal for engineering sciences 12.1 (2009): 26-37. [8] m. a.r mohammed and s. ali abed mohammed, “effect of additives on rheological properties of invert emulsions”, ijcpe, vol. 10, no. 3, pp. 31-39, sep. 2009. [9] zengeni b. t., “ bingham yield stress and bingham plastic viscosity of homogeneous nonnewtonian slurries”. cape peninsula university of technology, 2016. [10] mohammed, muhannad ar. "prediction of new correlations relating rheological properties of invert emulsions with temperature and pressure." iraqi journal of mechanical and material engineering 13.3 (2013): 604-617. [11] philips a., “so you want to be a mud engineer: an introduction to drilling fluids technology”. create space independent publishing platform. pages : 176 pages publisher : isbn-10 : 1477674969 isbn1,39781477674963, 2012. https://books.google.iq/books?hl=en&lr=&id=f2ov9tqygvwc&oi=fnd&pg=pp5&dq=%5b1%5d%09brujan,+e.+a.,+%e2%80%9ccavitation+in+non-newtonian+fluids+with+biomedical+and+bioengineering+applications%e2%80%9d.+springer+heidelberg+dordrecht+london+new+york+isbn+13:978-3-642-15343-3,+2011.&ots=reidzfb03j&sig=curreujflpvfpkk-0bknes24zi0&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=f2ov9tqygvwc&oi=fnd&pg=pp5&dq=%5b1%5d%09brujan,+e.+a.,+%e2%80%9ccavitation+in+non-newtonian+fluids+with+biomedical+and+bioengineering+applications%e2%80%9d.+springer+heidelberg+dordrecht+london+new+york+isbn+13:978-3-642-15343-3,+2011.&ots=reidzfb03j&sig=curreujflpvfpkk-0bknes24zi0&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=f2ov9tqygvwc&oi=fnd&pg=pp5&dq=%5b1%5d%09brujan,+e.+a.,+%e2%80%9ccavitation+in+non-newtonian+fluids+with+biomedical+and+bioengineering+applications%e2%80%9d.+springer+heidelberg+dordrecht+london+new+york+isbn+13:978-3-642-15343-3,+2011.&ots=reidzfb03j&sig=curreujflpvfpkk-0bknes24zi0&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=f2ov9tqygvwc&oi=fnd&pg=pp5&dq=%5b1%5d%09brujan,+e.+a.,+%e2%80%9ccavitation+in+non-newtonian+fluids+with+biomedical+and+bioengineering+applications%e2%80%9d.+springer+heidelberg+dordrecht+london+new+york+isbn+13:978-3-642-15343-3,+2011.&ots=reidzfb03j&sig=curreujflpvfpkk-0bknes24zi0&redir_esc=y#v=onepage&q&f=false https://www.sciencedirect.com/science/article/abs/pii/s026087740200211x https://www.sciencedirect.com/science/article/abs/pii/s026087740200211x https://www.sciencedirect.com/science/article/abs/pii/s026087740200211x https://www.sciencedirect.com/science/article/abs/pii/s026087740200211x https://pdfs.semanticscholar.org/e566/53870e7fa9fae61084b99ed982c07b03b431.pdf https://pdfs.semanticscholar.org/e566/53870e7fa9fae61084b99ed982c07b03b431.pdf https://pdfs.semanticscholar.org/e566/53870e7fa9fae61084b99ed982c07b03b431.pdf https://pdfs.semanticscholar.org/e566/53870e7fa9fae61084b99ed982c07b03b431.pdf https://pdfs.semanticscholar.org/e566/53870e7fa9fae61084b99ed982c07b03b431.pdf https://pdfs.semanticscholar.org/e566/53870e7fa9fae61084b99ed982c07b03b431.pdf https://onlinelibrary.wiley.com/doi/abs/10.1002/apj.2109 https://onlinelibrary.wiley.com/doi/abs/10.1002/apj.2109 https://onlinelibrary.wiley.com/doi/abs/10.1002/apj.2109 https://onlinelibrary.wiley.com/doi/abs/10.1002/apj.2109 https://onlinelibrary.wiley.com/doi/abs/10.1002/apj.2109 https://www.sciencedirect.com/science/article/abs/pii/s0169131716304963 https://www.sciencedirect.com/science/article/abs/pii/s0169131716304963 https://www.sciencedirect.com/science/article/abs/pii/s0169131716304963 https://www.sciencedirect.com/science/article/abs/pii/s0169131716304963 https://www.sciencedirect.com/science/article/abs/pii/s0169131716304963 https://www.sciencedirect.com/science/article/abs/pii/s0169131716304963 http://eprints.covenantuniversity.edu.ng/9826/#.xvy0a6ezbiu http://eprints.covenantuniversity.edu.ng/9826/#.xvy0a6ezbiu http://eprints.covenantuniversity.edu.ng/9826/#.xvy0a6ezbiu http://eprints.covenantuniversity.edu.ng/9826/#.xvy0a6ezbiu http://eprints.covenantuniversity.edu.ng/9826/#.xvy0a6ezbiu http://eprints.covenantuniversity.edu.ng/9826/#.xvy0a6ezbiu https://nahje.com/index.php/main/article/view/561 https://nahje.com/index.php/main/article/view/561 https://nahje.com/index.php/main/article/view/561 https://nahje.com/index.php/main/article/view/561 https://nahje.com/index.php/main/article/view/561 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/411 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/411 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/411 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/411 http://ir.cput.ac.za/handle/20.500.11838/2458 http://ir.cput.ac.za/handle/20.500.11838/2458 http://ir.cput.ac.za/handle/20.500.11838/2458 http://ir.cput.ac.za/handle/20.500.11838/2458 https://www.iasj.net/iasj?func=article&aid=87325 https://www.iasj.net/iasj?func=article&aid=87325 https://www.iasj.net/iasj?func=article&aid=87325 https://www.iasj.net/iasj?func=article&aid=87325 https://www.iasj.net/iasj?func=article&aid=87325 https://www.iasj.net/iasj?func=article&aid=87325 https://www.amazon.com/you-want-mud-engineer-introduction/dp/1477674969 https://www.amazon.com/you-want-mud-engineer-introduction/dp/1477674969 https://www.amazon.com/you-want-mud-engineer-introduction/dp/1477674969 https://www.amazon.com/you-want-mud-engineer-introduction/dp/1477674969 https://www.amazon.com/you-want-mud-engineer-introduction/dp/1477674969 d. h. ali and m. a.r. mohammed / iraqi journal of chemical and petroleum engineering 21,2 (2020) 47 56 55 [12] caenn r., darley h. c. h. and gray g. r., “composition and properties of drilling and completion fluids”, sixth edition. gulf professional publishing, 2011. [13] chhabra, raj p. bubbles, drops, and particles in non-newtonian fluids. crc press, 2006. [14] steffe j. f., “rheological methods in food process engineering”. freeman press, usa , 2nd edition , 1996. [15] mohammed, m.a.r., “flow model selection for invert emulsions using temperatures”. the iraqi journal for mechanical and material engineering, vol.14, no1., 2014. [16] instruction manual. ofi testing equipment, inc. texas, u.s.a. updated 8/7/2019 ver. 9. 24pages, 2015. https://books.google.iq/books?hl=en&lr=&id=ohzanicqpmyc&oi=fnd&pg=pp1&dq=composition+and+properties+of+drilling+and+completion+fluids&ots=ebbtyudjcx&sig=_jdo9bkarvuo-esjz38iafxxxqu&redir_esc=y#v=onepage&q=composition%20and%20properties%20of%20drilling%20and%20completion%20fluids&f=false https://books.google.iq/books?hl=en&lr=&id=ohzanicqpmyc&oi=fnd&pg=pp1&dq=composition+and+properties+of+drilling+and+completion+fluids&ots=ebbtyudjcx&sig=_jdo9bkarvuo-esjz38iafxxxqu&redir_esc=y#v=onepage&q=composition%20and%20properties%20of%20drilling%20and%20completion%20fluids&f=false https://books.google.iq/books?hl=en&lr=&id=ohzanicqpmyc&oi=fnd&pg=pp1&dq=composition+and+properties+of+drilling+and+completion+fluids&ots=ebbtyudjcx&sig=_jdo9bkarvuo-esjz38iafxxxqu&redir_esc=y#v=onepage&q=composition%20and%20properties%20of%20drilling%20and%20completion%20fluids&f=false https://books.google.iq/books?hl=en&lr=&id=ohzanicqpmyc&oi=fnd&pg=pp1&dq=composition+and+properties+of+drilling+and+completion+fluids&ots=ebbtyudjcx&sig=_jdo9bkarvuo-esjz38iafxxxqu&redir_esc=y#v=onepage&q=composition%20and%20properties%20of%20drilling%20and%20completion%20fluids&f=false https://books.google.iq/books?hl=en&lr=&id=ekirbgaaqbaj&oi=fnd&pg=pp1&dq=bubbles,+drops,+and+particles+in+non-newtonian+fluids&ots=t3qdfjmkio&sig=jelw99tiet5lfkqzulafhjn063e&redir_esc=y#v=onepage&q=bubbles%2c%20drops%2c%20and%20particles%20in%20non-newtonian%20fluids&f=false https://books.google.iq/books?hl=en&lr=&id=ekirbgaaqbaj&oi=fnd&pg=pp1&dq=bubbles,+drops,+and+particles+in+non-newtonian+fluids&ots=t3qdfjmkio&sig=jelw99tiet5lfkqzulafhjn063e&redir_esc=y#v=onepage&q=bubbles%2c%20drops%2c%20and%20particles%20in%20non-newtonian%20fluids&f=false https://books.google.iq/books?hl=en&lr=&id=lrrdonust9kc&oi=fnd&pg=pr9&dq=%5b7%5d%09steffe+j.+f.,+%e2%80%9crheological+methods+in+food+process+engineering%e2%80%9d.+freeman+press,+usa+,+2nd++edition+,+1996.&ots=k_zlja2ee1&sig=vjsn3d6s1kdvvd9ns7lqwysyyh8&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=lrrdonust9kc&oi=fnd&pg=pr9&dq=%5b7%5d%09steffe+j.+f.,+%e2%80%9crheological+methods+in+food+process+engineering%e2%80%9d.+freeman+press,+usa+,+2nd++edition+,+1996.&ots=k_zlja2ee1&sig=vjsn3d6s1kdvvd9ns7lqwysyyh8&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=lrrdonust9kc&oi=fnd&pg=pr9&dq=%5b7%5d%09steffe+j.+f.,+%e2%80%9crheological+methods+in+food+process+engineering%e2%80%9d.+freeman+press,+usa+,+2nd++edition+,+1996.&ots=k_zlja2ee1&sig=vjsn3d6s1kdvvd9ns7lqwysyyh8&redir_esc=y#v=onepage&q&f=false https://www.iasj.net/iasj?func=article&aid=90354 https://www.iasj.net/iasj?func=article&aid=90354 https://www.iasj.net/iasj?func=article&aid=90354 https://www.iasj.net/iasj?func=article&aid=90354 d. h. ali and m. a.r. mohammed / iraqi journal of chemical and petroleum engineering 21,2 (2020) 47 56 56 دراسة الخواص الريولوجية للسوائل غير النيوتونية تحت تأثير درجات الحرارة باستخدام إضافات كيميائية مختلفة مهند عبد الرزاق محمدو دعاء حسين علي العراق -جامعة النهرين -كلية الهندسة -قسم الهندسة الكيمياوية الخالصة يدرس هذا البحث الخواص الريولوجية )اللزوجة البالستيكية ، نقطة الخضوع واللزوجة الظاهرية( للسوائل غير النيوتونية تحت تأثير درجات الحرارة باستخدام إضافات كيميائية مختلفة، مثل زانثان بوليمر ، كربوكسي فضة(، بولي أكريالميد ، كحول بولي فينيل ، نشا ، كيوبراجو وكروم ميثيل السليلوز ) اللزوجة العالية والمنخ ضافة 350غرام من البنتونيت مع 22.5ليجنو سلفونات، تم تحضير العينات عن طريق خلط مل من الماء وا تم قياس . ( غرام باستخدام خالط هاميلتون بيتش13، 9، 6، 3المواد المضافة في أربعة تركيزات مختلفة ) واص الريولوجية للعينات المحضرة باستخدام نموذج مقياس اللزوجة فان ثمانمئة ذوو ثمان سرعات. تخضع الخ درجة فهرنهايت. 200إلى 50جميع العينات لنموذج بينغهام بالستيك. تتراوح درجة الحرارة المدروسة من ظاهرية ونقطة الخضوع ( انخفضت مع أظهرت النتائج أن الخواص الريولوجية )اللزوجة البالستيكية ، اللزوجة ال .زيادة درجة الحرارة لجميع عينات تحضير الموائع غير النيوتونية بينغهام البالستيك نموذج ، النيوتونية غير السوائل ، الريولوجية الكلمات الدالة: الخواص iraqi journal of chemical and petroleum engineering vol.13 no.4 (december 2012) 112 issn: 1997-4884 prediction of the chemical composition and physical properties of aged asphalt cement abdulhalim a-k mohammed and khalid mershed eweed university of baghdad, college of engineering, chemical engineering department baghdad, iraq abstract in the present work a modification was made on three equations to represent the experiment data which results for iraqi petroleum and natural asphalt. the equations have been developed for estimating the chemical composition and physical properties of asphalt cement at different temperature and aging time. the standard deviations of all equations were calculated. the modified correlation related to the aging time and temperature with penetration index and durability index of aged petroleum and natural asphalts were developed. the first equation represents the relationship between the durability index with aging time and temperature. the second equation represents the relationship between the penetration index with aging time and temperature.     2 431 2013.0log tbbtbpi e  the third equation represents the relationship between the durability index with penetration index.    diapi eee log5627.0loglog  the values of penetration index and durability index for all aged samples were compared with predicted values. these correlations give a percent of error in the range of 1.2 to 7.4%. kew word: chemical composition of asphalt, physical properties of asphalt, asphalt properties, and durability of asphalt introduction evaluation of asphalt physical and chemical properties is of great importance since they are directly related to the performance of asphalt pavement. asphalt, which remains after vacuum distillation of crude oil, is a complex mixture of organic and inorganic compounds. such compounds may be separated into asphaltenes, saturated compounds, polar aromatic compounds, and              ttatadi ee 2 1 30 1 log20123.0)(log 2 31 iraqi journal of chemical and petroleum engineering university of baghdad college of engineering prediction of the chemical composition and physical properties of aged asphalt cement 2 ijcpe vol.13 no.4 (december 2012) -available online at: www.iasj.net naphthene aromatic compounds [1]. asphaltenes are defined as the blackcolored fraction of bitumen that is insoluble in n-heptane. asphalt is an extremely versatile material and its usage is widespread from paving, road building, and roofing to protective coating and hydraulic structures. asphalt has these and various other uses as a result of certain properties it possesses like its ductility, durability, cohesiveness, its adhesive nature and its waterproof nature [2]. these properties vary greatly among different types of asphalt just as petroleum differs according to where it is obtained. processes employed in asphalt manufacture include atmospheric-vacuum distillation, airoxidation, solvent extraction or precipitation, chemical treatment and blending of individual stocks[3]. natural bitumen is usually byproduct that have petroleum base and they produced from underground storages stones or they will rise up on its surface by ground layers. if bitumen rises on the ground surface it can constitute bituminous springs and if stay inside the ground and closed its force path it will be solidified and oxidized and extremely it will make a solid and hard substance that called mineral bitumen. gilsonite is mineral bitumen, black and brittle, which is easily crushed into powder [4]. natural bitumen is used in different industries such as petroleum production road making, found, making covers and making colors but natural bitumen directly is not used in this industry and usually it is added to the base material in the form of additive material. this combination can have different purposes like improvement of physical or chemical properties produce production with more variety or produce production with less final cost. in the petroleum derivation process that can mentioned to the shale stabilization. these additives have not any kind of effects on swelling pressure. also, their significant bulk size prevents them from entering shales and effectively blocking pore throats. therefore, filtrate invasion and mud pressure penetration will proceed unretarded [5]. ishaiet[6,7] have adopted the durability index to reflect the relationship between aging and the internal colloidal structure of an asphalt . this index is given by the ratio of the sum of the asphaltenes and saturates to the sum of the polar aromatics and naphthene aromatics (equation 1). di= napa sa   …(1) where, a is the asphaltenes content, s is the saturates content, pa is the polar aromatics content and na is the naphthene aromatics. thus if the rate of deviation of the colloidal condition from the optimum or the initial could be considered as representing a measure of the susceptibility of the asphalt to durability problems , then the durability index could play a useful role[8]. the asphaltenes and polar aromatics fraction are considered the solid portion and, therefore, as the phase dispersed in an oily medium supplied but the resins components. asphaltenes phase are thought to be convert by a sheath of high–molecular –weight, aromatic resin acting as a stabilizing solvating layer. there is a gradual reduction in the resinous character of a medium in a direction away from the center of a micelle. a stabilized micelle would not normally precipitate unit a solvent is added to reduce the peptizing power of the dispersion medium, thus affording the asphaltenes the freedom to agglomerate and precipitate. this idea presents asphaltenes as being some discrete abdulhalim a-k mohammed and khalid mershed eweed -available online at: www.iasj.net ijcpe vol.13 no.4 (december 2012) 3 particles already existing in the asphalt ; according to bodusznski[8] et al., however , it is the non-polar solvent that upsets the solubility equilibrium of the system and causes the most polar compound types to agglomerate and precipitate as a asphaltenes [9]. simulation of aging time of asphalt cements is a widely used procedure in asphalt cements characterization for predicting the durability response to plant mixing and paving under controlled laboratory conditions. there are numerous equation for evaluating the aging time of asphalt cement. anderson [10] is used an exponential model for predicting the aging time of asphalt cement, represented as equation 2 and 3. …(2) …(3) where, t is the aging time in thin film oven test; t is the temperature; a1 and a2 are the model coefficients for predicting the physical properties of asphalt cements, a3 and a4 are the temperature shift coefficients , b1 , b2, and b3 are the model coefficient for evaluating the chemical properties of asphalt cements, b4 and b5 are the temperature shift coefficient .the coefficients a1, a2, b1, b2, and b3 are obtained using least squares regression of equations 2 and 3 and using the temperature shift coefficients a3, a4, b4, and b5 .anderson found that the error are higher close to the middle range of temperature (30-46 o c) as well as at extreme low and high temperature. this predictions can be improved if this models are used for the high temperature and intermediate temperature; however, this will result in an increased complexity of the models and associated shift factors. the error is insignificant except at the lowest test temperature of 7 o c, which reflects the inability of the model to capture this extreme range. brule b. [11] suggests a definite relation between the durability index and asphalt viscosity or penetration of asphalt cement. this relation is equation 3-4 contained two parameters. …(4) where, a and b are the parameters of equation 4; n is the viscosity or penetration of the asphalt cements ; and di is the durability index of the asphalt cements .this equation is applied on asphalt cements (paving grade) for evaluating the durability index at any viscosity or penetration. the parameters a and b are obtained using least square method of equation 4. brule found that a strong correlation exists between the durability index and physical property (viscosity and penetration). this correlation is a confirmation of the fact that asphalt rheology is a direct consequence of the interaction of the fractional components and that the durability index summarizes the overall colloidal character of an asphalt during aging. eyring [10] developed an a approximate theor, for the estimation of viscosity as a function of temperature. this theory is based on the physical properties of the heavy liquids or semi-solid. amin and maddox [12, 13] reviewed the common correlation used for the prediction of the heavy liquid viscosity. benson [14] addressed the relation between low temperature cracking of asphalt pavements in texas, and asphalt hardening. nine test sections were evaluated in detail and relationship between asphalt physical properties and performance established. good correlations were found between the viscosity at 25 o c,      te atataattp 4 2 321 ),(log          35 2 42 2 5 2 41 , btbtbtbtbtbtbttc     diban e log prediction of the chemical composition and physical properties of aged asphalt cement 4 ijcpe vol.13 no.4 (december 2012) -available online at: www.iasj.net aging index, and air voids with performance. laboratory mixture samples17 in. in diameter by 2 in. deep was compared using a texas gyrator compactor. these laboratory samples were called pizzas. pizzas were aged in the field in two locations with different levels of solar radiation and precipitation. control sets were stored in the laboratory. after three years the pizzas were cored, tested for resilient modulus, and penetration and viscosity tests, both at 25 o c were carried out on the recovered asphalt. the majority of pizzas were regular dense mix. however, a set of 15 was made using an antihardening additive. this was a combination of paraphenyciene diamine antiozonates and ultraviolet light inhibitors, at a treatment level of 1%. benson also conducted the ``actinic light test`` on asphalt samples. the test was conducted on 10 micron films with the following conditions: 95 o c, 18 hours, and 100 micro-watts/cm 3 of 3660 angstrom wavelength radiation. these are identical to the condition reported by kemp and predoehi. the thin film oven test was also conducted [13,14].an excellent feature of benson’s study is the hardening models developed. these were developed for viscosity and penetration and take the form of equation 5 and 6. …(5) …(6) where, is the kinematic viscosity at 25 o c, p is the penetration at 25 o c, t is the time (months), and a, b, c and d are the coefficients of equation 5 and 6. benson notes that the key to applying this model is to predict the parameter, ``c`` and ``d``, and that ``d`` is a measure of short-term hardening. since when t is equal to one month. …(7) the parameter ``c`` relates to the curvature and represents long-term aging susceptibility. a predictive equation for ``c`` was developed from multiple regression analysis, yielding …(8) where, orp is the original penetration. the aim of the present work deals with study a method for prediction a relationship between the aging time and temperature with durability index and penetration index. also, study a method for prediction a correlation between the durability and penetration index for aged natural and petroleum asphalt cements at different aging time and temperatures. experimental three grades of petroleum asphalt are supplied from daura refinery, while two grades of natural asphalt is brought from hiit city. the physical and chemical properties of these asphalt cements are presented in table 1 and 2. penetration test penetration (astm-d1754) is a test for the consistency of asphalt. it is based on a standard needle entering asphalt under fixed conditions. the depth of the peneteration of the standard needle into the material to be tested within 5 seconds, with a load of 100gm at 25 o c is measured in this standard tests. the penetration is measured in 0.1 mm. group composition separation test group composition (astm-d2024) for all petroleum and natural and aged asphalts are determined by adsorption chromatography. a glass percolation column (20 mm diameter, 400 mm height) was filled with 300 gm b at  tdcp     cdcp  1ln   252.0  orpc abdulhalim a-k mohammed and khalid mershed eweed -available online at: www.iasj.net ijcpe vol.13 no.4 (december 2012) 5 activated alumina f20. a 500 ml separating funnel containing the deasphaltened sample was put in the top of the column. durability test the standard thin film oven test (astm-d1754) has been employed to aged the asphalt film at different temperatures and times for various types of petroleum and natural asphalt cements. all aged samples have been tested for penetration, kinematic viscosity, softening point, heat loss, and solubility in trichloroethylene. separation of asphaltenes, polararomatics, naphthene-aromatics, and saturates were carried on all aged samples. the changes in physical properties and chemical composition properties of asphalt cements due to the effect of heat and air are evaluated by thin film oven test .in all tests 3.2 mm film thickness of asphalt cements is placed in cylindrical pans in an ovenmaintained at temperatures 150, 163, and 175 o c for aging intervals 5, 10, 15, 20, 25 and 30 hours. changes in the various physical and chemical properties after oven aging are then determined. result and discussion ishaiet [6, 7] summarized the chemical composition of petroleum and natural asphalt cement according to the durability index. the durability index was calculated by equation 1 which correlated with di. in this investigation a correlation 9 has been developed for prediction chemical composition of asphalt cement according to the di base as a function of aging and temperature. the correlation was tested on a range of temperature 150 to 175 o c and a range of aging time 5 to 30 hours.              ttataadi ee 2 1 30 1 log2)(log 2 321 …(9) where, t and t are the aging time (hours) and temperature ( o c), respectively, a1, a2, and a3 are the parameter of equation 9. the mean and standard deviation error for prediction of durability index by using equation 9 is calculated by statistical method. the values of empirical parameters of equation 9 with sd and error for each aged samples of asphalt cements are summarized in table 3. this table indicates that the correlation is yielded lowest value of mean and standard deviation for all aged asphalt cements. figures 1 to 3 show the observed value and predicted value of durability index with aging time at 150 o c. these figures report that a strong correlation exists between the durability index and aging time. therefore, the correlation 9 simple to use and gives results in good agreement with experimental values. the prediction values are reported in table 4 to 6. the parameter a2 in equation 9 represents the slope of this equation. the values of parameter a2 is ranged from 0.0067 to 0.0164. this parameter can be considered as a constant value. an average slope for all aged asphalt was 0.0123. this average value could be used as the value of parameter a2 and it gives the best percent of error between the experimental and predicted durability index of aged asphalt cement. then the equation 9 could be written as:              ttatadi ee 2 1 30 1 log20123.0)(log 2 31 …(10) equation 10 contains two parameters a1 and a3 which can be calculated by least square method. these calculated parameter and percent error are prediction of the chemical composition and physical properties of aged asphalt cement 6 ijcpe vol.13 no.4 (december 2012) -available online at: www.iasj.net summarized in table 7. the percent error was ranged from 2.5 to 5.45, so this equation gives better agreement with experimental values, than equation 9. to predict the physical properties of an asphalt cement as a function of aging time and temperature, the penetration index is used. equation 3 can be used to predict the physical properties is represented by penetration index proposed originally by a. shalabiy [15]. a modification of equation 3 was done to obtain equation 11.     2 4321 log tbbtbbpi e  …(11) where, pi is the penetration index, b1, b2, b3, and b4 are the parameters of equation 11, t is the aging time (hour), and t is the temperature ( o c). the parameters of equation 11 are obtained using least square method. the values of parameters, standard deviation and percent of error for equation 11 are shown in table 8. the parameter b2 is represented the slope of equation 11. it is seen from the table 8, that the equation 11 gives acceptable agreement with experimental data, where the percent of error for all aged samples is ranged from 1.5 to 6.5. the parameter b2 in equation 11 represents the slope of this equation. from table 8 it is interesting to note that the values of parameter b2 in equation 11 can be considered as a constant value by taking the average slope for all aged asphalt. this average value of the slops is equal to –0.2013. then equation 11 become as follow:     2 431 2013.0log tbbtbpi e  …(12) the values of parameters, sd, and the percent of error for equation 12 are summarized in table 9. it is seen from the table 9, that the equation 12 gives acceptable agreement with experimental data, where the percent of error for all aged samples is ranged 2.2 to 7.4. to avoid using a single component fraction to estimate the behavior of an asphalt in the aging process. ishaiet [6, 7] favor the use of the durability index in terms of its colloidal stability during aging. thus durability index can be correlated with the physical character of asphalt by measuring the penetration index. the penetration index summarize the softening point and penetration of asphalts. equation 4 can be used to predict the physical properties with chemical composition is proposed originally by brule b[11]. in this work a modification for equation 4 was done and equation 13 was obtained for all aged asphalt cement.    dibapi ee logloglog  …(13) where, pi is the penetration index , di is the durability index and a and b are the parameters of equation 13. the values of the parameters, sd, and percent of error of equation 13 based on experimental data of aged asphalt are summarized in table 10. this table indicates that equation 13 gives acceptable agreement with experimental data, where the percent of error ranged from 1.4 to 5.3. equation 13 indicates that the parameter b are represented the slope of this equation. this slope for all aged asphalt can be considered as one value by taking the slop average. the value of the parameter b is ranged from – 0.3401 to –0.8102%. therefore, the value average of b is –0.5627. so the final equation becomes:    diapi ee log5627.0loglog  …(14) the values of parameter a, the percent of error, and sd for equation abdulhalim a-k mohammed and khalid mershed eweed -available online at: www.iasj.net ijcpe vol.13 no.4 (december 2012) 7 14 are summarized in table 11. this table indicate that the results calculated by equation 14 were very satisfactory with a percent of error ranged from 1.2 to 5.9 %. conclusions three equations are developed to predict the chemical and physical properties of natural and petroleum asphalt. 1. the first equation is developed to evaluate the durability index with aging time at a wide range of temperature. 2. the second equation is developed to evaluate the penetration index with aging time at a wide range of temperature. 3. the third equation is developed to evaluate the durability index with penetration index for all aged asphalt cement. nomenclature a asphaltenes (% by wt.) di durability index n naphthene aromatic content, (%, by wt.) p penetration, (0.1 mm) pa polar aromatic content, (%, by wt.) pi penetration index s saturation content , (%, by wt.) sp softening point. oc sd standard deviation t temperature, (oc) t aging time, (hour) references 1. hozayain a. h. and a. m. othman gulf conference 2008. 2. garcia-morales m., partal p., navarro f.j., martý´nez-boza f., gallegos c., gonza´lez n., gonza´lez o., mun˜oz m.e., “viscous properties and microstructure of recycled eva modified bitumen”, fuel, vol 83, 31-38, 2003. 3. wardlaw k.r., shuler s., “polymer modified asphalt binders”, astm stp1108, 1992 4. m. ameri, a. mansourian, s. s.ashani, g. yadollahi, “technical study on the iranian gilsonite as an additive for modification of asphalt binders used in pavement construction”, construction and building materials, vol. 25(3), 2011, p1379-1387. 5. e.v. oort,” on the physical and chemical stability of shales”, journal of petroleum science and engineering, vol. 38, 2003, p213– 235 6. ishai, i. and y. a. tuffour, proc. assoc. of asphalt paving technologists, 56, 1987. 7. ishai, i, astm journal of testing and evaluation, jteva, 5, 3, may, 1987. 8. tuffour y. a., proc. assoc. of asphalt paving technologists, 58, 1989. 9. brule b., a paper presented at the 67th annual meeting of the trb, january 1986. 10. anderson, d. binder characterization and evaluation, 3, 1994, internet sit. 11. brule. b., laboratory central des ponts and chaaussees (lcpc), paris , october 1986. 12. eyring h. j., oil and gas journal, 45, 1995. 13. goodrich, chevron, usa, asphalt division 1989. 14. benson, p. e., texas transportation institute & state department of highway and public transportation, 1976. 15. shalebiy a., can. civ. eng., 29, pp. 135-144, 2002. prediction of the chemical composition and physical properties of aged asphalt cement 8 ijcpe vol.13 no.4 (december 2012) -available online at: www.iasj.net table 1, physical and chemical properties of petroleum asphalt cements test petroleum asphalt grade test method 40-50 60-70 21-30 1 penetration (0.1mm) 48 68 22 astm-d5 2 softening point r&b( o c) 51 50 87 astm-d36 3 kinematic viscosity at 135 o c (cst) 443 356 1042 astm-d2170 4 solubility in trychloroethylene (% wt.) 99.7 99.8 99.1 astm-d86 5 fractional composition (%wt) astm-d2024 asphaltenes 21.2 17.9 34.1 saturates 21.3 16.3 22.3 naphthene-aromatics 44.5 45.9 30.5 polar-aromatics 11.5 20.9 13.0 6 thin film oven test 0.3 astm-d1754 loss by heating (% wt.) 0.5 0.3 penetration (0.1mm) 36 46 16 softening point( o c) 54 55 90 table 2, physical and chemical properties of natural asphalt cements test natural asphalt grade test method 49 35 1 penetration (0.1mm) 49 35 astm-d5 2 softening point r&b( o c) 66 78 astm-d36 3 kinematic viscosity at 135 o c (cst) 428 625 astm-d2170 4 solubility in trichloroethylene (% wt.) 88.6 89.2 astm-d86 5 fractional composition (% wt.) 10.2 asphaltenes 17.9 astm-d2024 saturates 9.7 17.9 naphthene-aromatics 53.4 49.7 polar-aromatics 19.9 21.9 6 thin film oven test 2.0 2.5 loss by heating (% wt.) astm-d1754 penetration(0.1mm) 39 28 softening point( o c) 68 83 table 3, the parameters of equation 9 for aged natural and petroleum asphalt cements at different temperatures asphalt grade temperature , o c a1 a2 a3 sd error, % 60-70 150 -0.79699 0.00671 -1.50124 0.46 4.53 60-70 163 -0.73535 0.00736 -1.50213 0.47 4.67 60-70 175 -0.74339 0.00903 -1.52960 0.48 6.58 40-50 150 -0.47818 0.01047 -1.24173 0.49 7.56 40-50 163 -0.39966 0.01032 -1.24530 0.45 3.58 40-50 175 -0.37199 0.01100 -1.25480 0.46 2.54 21-30 150 +0.09746 0.00889 -1.05035 0.24 2.65 21-30 163 0.007867 0.01608 -0.88926 0.15 8.11 21-30 175 +0.01623 0.01611 -0.92119 0.4 7.68 35 150 -1.08704 0.00794 -1.67659 1.03 7.58 35 163 -1.06080 0.00811 -1.70790 3.15 7.64 35 175 -1.05859 0.00791 -1.75119 1.25 6.68 49 150 -1.06488 0.00706 -1.67414 0.26 8.22 49 163 -1.04464 0.00726 -1.70882 0.25 8.95 49 175 -0.99915 0.00772 -1.71534 0.28 8.65 abdulhalim a-k mohammed and khalid mershed eweed -available online at: www.iasj.net ijcpe vol.13 no.4 (december 2012) 9 table 4, predicted value of durability index with aging time for aged asphalt cement grade 60-70 and 40-50 aging time, hour predicted di of asphalt grade 60-70 at 150 o c predicted di of asphalt grade 60-70 at 163 o c predicted di of asphalt grade 60-70 at 175oc predicted di of asphalt grade 40-50 at 150 o c predicted di of asphalt grade 40-50 at 163 o c 0 0.496 0.519 0.727 0.727 0.752 5 0.542 0.584 0.818 0.818 0.874 10 0.591 0.652 0.917 0.917 1.002 15 0.643 0.720 1.025 1.023 1.130 20 0.697 0.787 1.142 1.322 1.256 25 0.755 0.852 1.267 1.427 1.376 30 0.8163 0.914 1.462 1.434 1.482 table 5, predicted value of durability index with aging time for aged asphalt cement grade 40-50 and 21-30 aging time, hour predicted di of asphalt grade 4050 at 175 o c predicted di of asphalt grade 21-30 at 150 o c predicted di of asphalt grade 21-30 at 163oc predicted di of asphalt grade 21 -30 at 175 o c predicted di of asphalt grade 35 at 150 o c 0 0.7974 1.2300 1.3258 1.3425 0.3993 5 0.9241 1.4256 1.5146 1.5564 0.4187 10 1.0591 1.5125 1.7324 1.79252 0.4413 15 1.1998 1.6325 1.9567 2.0435 0.4672 20 1.3440 1.7626 2.2024 2.3145 0.4971 25 1.4884 1.8923 2.4671 2.5934 0.5314 30 1.8780 2.0425 2.7467 2.8874 0.5708 table 6, predicted value of durability index with aging time for aged natural asphalt cements grade 35 and 49 aging time, hour predicted di of asphalt grade 35 at 163 o c predicted di of asphalt grade 35 at 175 o c predicted di of asphalt grade 49 at 150 o c predicted di of asphalt grade 49 at 163 o c predicted di of asphalt grade 49 at 175 o c 0 0.4016 0.4027 0.3715 0.3732 0.3856 5 0.4273 0.9395 0.4169 0.4246 0.451 10 0.4622 0.4837 0.4661 0.4635 0.5186 15 0.5082 0.5376 0.5176 0.5413 0.587 20 0.5672 0.6029 0.5695 0.5985 0.6548 25 0.6442 0.8266 0.5224 0.6552 0.7106 30 0.7427 0.7799 0.6764 0.7092 0.7762 table 7, the parameter of equation 10 for aged natural and petroleum asphalt cement at different temperature asphalt grade temperature, o c a1 a3 sd error, % 60-70 150 -1.8616 -0.0818 1.52 2.56 60-70 163 -1.7631 -0.1123 1.54 2.42 60-70 175 -1.8183 -0.0899 1.58 2.45 40-50 150 -1.4484 -0.1056 1.54 4.26 40-50 163 -1.3898 -0.1044 1.53 4.65 40-50 175 -1.3801 -0.1265 1.52 4.87 21-30 150 -0.9123 -0.0759 0.67 5.36 21-30 163 -0.8513 -0.1162 0.68 5.25 21-30 175 -0.8382 -0.1207 0.65 5.45 35 150 -2.1208 -0.1082 0.82 3.52 35 163 -2.1073 -0.1126 0.56 3.85 35 175 -2.1247 -0.1125 0.58 3.47 49 150 -2.1205 -0.0962 0.82 3.67 49 163 -2.1128 -0.10088 1.34 2.56 49 175 -2.0703 -0.1076 1.35 2.41 prediction of the chemical composition and physical properties of aged asphalt cement 10 ijcpe vol.13 no.4 (december 2012) -available online at: www.iasj.net table 8, the parameters of equation 11 for aged natural and petroleum asphalt cements at different temperatures asphalt grade t, o c b1 b2 b3 b4 sd error, % 60-70 150 5.1997 -0.5242 7.6657 1.0670 2.3400 4.2500 60-70 163 3.2452 -0.2114 3.9908 0.3823 1.4890 4.6700 60-70 175 3.2538 -0.0216 3.8575 0.0477 1.4567 5.3700 40-50 150 4.8011 -0.5097 7.6389 1.0554 1.9200 5.6480 40-50 163 1.3542 -0.6350 0.0889 0.8419 2.0642 5.7854 40-50 175 1.2701 -0.0042 3.0526 0.3056 2.0365 6.4820 21-30 150 5.3118 -0.5166 7.6336 1.0530 2.3564 2.3450 21-30 163 2.0095 -0.0082 3.6363 0.1635 2.5845 5.4558 21-30 175 1.8267 -0.0017 2.0263 0.2548 2.5687 2.3542 35 150 1.8266 -0.0018 1.9732 0.2474 2.9860 1.6500 35 163 1.9791 -0.0042 1.0886 0.1434 2.3580 7.3500 35 175 1.9642 -0.0048 0.4029 0.1719 1.5680 1.5680 49 150 5.7338 -0.5463 7.7209 1.0865 1.8650 6.1350 49 163 1.70915 -0.0024 3.7670 0.3149 1.025 6.1235 49 175 1.73552 -0.0028 5.7351 0.3866 1.0265 1.9860 table 9, the parameters of equation 12 for aged natural and petroleum asphalt cements at different temperatures asphalt grade t, o c b1 b3 b4 sd error, % 60-70 150 -11.0929 -2.9345 -0.0029 1.2800 4.3658 60-70 163 -10.9520 -2.8250 -0.0050 1.3589 4.9867 60-70 175 -11.3116 -2.8559 -0.0062 1.2568 6.2365 40-50 150 -11.3676 -2.9655 -0.0041 2.2356 4.3255 40-50 163 -11.3468 -2.7983 -0.0042 2.2568 5.2365 40-50 175 -11.3683 -2.6324 -0.0041 2.8670 3.6569 21-30 150 --2.5898 -1.3417 0.0028 2.2654 2.21658 21-30 163 -2.02278 -1.7356 0.0076 2.5689 5.3658 21-30 175 -2.9255 -0.9369 0.0063 3.1256 3.0023 35 150 -2.4660 -1.3695 0.0018 2.2365 5.7890 35 163 -14.2725 -3.8974 0.0028 5.2356 7.3500 35 175 -22.2107 -5.8224 0.0030 3.5659 2.0576 49 150 -23.8407 -6.3238 0.0018 1.2256 6.2350 49 163 -20.6682 -5.5119 0.0021 2.9867 4.2356 49 175 -30.4734 -7.5612 0.0021 2.3654 2.3659 table 10, the parameters of equation 13 for aged natural and petroleum asphalt cements at different temperatures asphalt grade t, o c a b sd error, % 60-70 150 1.1038 -0.5323 0.2660 2.3546 60-70 163 0.9974 -0.7845 0.5623 1.5680 60-70 175 1.0039 -0.7792 0.5433 3.2564 40-50 150 1.1190 -0.5763 0.3000 1.3568 40-50 163 1.1284 -0.6415 0.6701 2.3250 40-50 175 1.1421 -0.6103 0.9911 4.2350 21-30 150 1.8407 -0.3403 0.3837 3.5600 21-30 163 1.9016 -0.5022 0.5863 4.0020 21-30 175 2.0062 -0.7900 0.7460 5.0102 35 150 1.3461 -0.5139 0.4914 5.3260 35 163 1.3613 -0.4874 0.51263 4.2200 35 175 1.2729 -0.5110 0.7461 4.3265 49 150 1.3711 -0.3750 0.5687 4.0025 49 163 1.3407 -0.4014 0.8925 5.0002 49 175 1.3346 -0.5291 0.54821 3.4520 abdulhalim a-k mohammed and khalid mershed eweed -available online at: www.iasj.net ijcpe vol.13 no.4 (december 2012) 11 table 11, the parameter of equation 14 for aged natural and petroleum asphalt cements at different temperatures asphalt grade t, o c a sd error, % 60-70 150 1.0893 0.3660 1.2356 60-70 163 1.0849 0.6523 1.9820 60-70 175 1.0764 0.7213 3.0254 40-50 150 1.1195 0.3120 1.3023 40-50 163 1.1259 0.6103 3.5680 40-50 175 1.1195 1.0911 4.9720 21-30 150 1.9445 1.0330 3.72562 21-30 163 1.9332 0.6860 5.1240 21-30 175 1.8660 0.8250 5.32102 35 150 1.3087 0.3568 5.9250 35 163 1.3093 0.5613 4.0010 35 175 1.2942 0.5681 4.0001 49 150 1.2365 1.3568 5.3200 49 163 1.2301 0.9925 4.0025 49 175 1.3128 0.5531 3.4520 fig. 1, observed and predicted value of durability index for aged asphalt cement grade 60-70 at 150°c predicted values obse rved value s 0.45 0.55 0.65 0.75 0.85 0.95 0.45 0.55 0.65 0.75 0.85 0.95 prediction of the chemical composition and physical properties of aged asphalt cement 12 ijcpe vol.13 no.4 (december 2012) -available online at: www.iasj.net fig. 2, observed and predicted value of durability index for aged asphalt cement grade 60-70 at163°c fig. 3, observed and predicted value of durability index for aged asphalt cement grade 60-70 at 175 o c predicted values obse rved value s 0.48 0.54 0.60 0.66 0.72 0.78 0.84 0.48 0.53 0.58 0.63 0.68 0.73 0.78 0.83 predicted values obse rved value s 0.45 0.55 0.65 0.75 0.85 0.95 1.05 1.15 0.45 0.55 0.65 0.75 0.85 0.95 1.05 1.15 iraqi journal of chemical and petroleum engineering vol.18 no.4 (december 2017) 35 45 issn: 1997-4884 heat transfer and hydrodynamic in internal jacket airlift bioreactor with microbubble technology mahmood k. h. al-mashhadani department of chemical engineering, college of engineering, university of baghdad, baghdad e-mail: mkh_control@yahoo.com abstract integration of laminar bubbling flow with heat transfer equations in a novel internal jacket airlift bioreactor using microbubbles technology was examined in the present study. the investigation was accomplished via multiphysics modelling to calculate the gas holdup, velocity of liquid recirculation, mixing time and volume dead zone for hydrodynamic aspect. the temperature and internal energy were determined for heat transfer aspect. the results showed that the concentration of microbubbles in the unsparged area is greater than the chance of large bubbles with no dead zones being observed in the proposed design. in addition the pressure, due to the recirculation velocity of liquid around the draft tube, increased the retention time of microbubbles in the same area. thus it was expected that their effect on mass and heat transfer phenomena would be positive for biological applications. for example the gas fraction volume of microbubble in the downcomer region is 0.0063, while with fine bubble diameter of 1 mm, this region was free from any bubble. furthermore, the velocity of liquid in the center of ring diffuser would be 0.175 m/s, if the sparging system operated with bubble diameter of 100 micrometer, whilst would be 0.035 m/s with fine bubble diameter of 1 mm. the study also proved the importance of bubble diameter on the heat transfer in gas and liquid phases in the proposed design. microbubbles gave greater responsiveness to stability and homogeneity in all parts of the bioreactor. finally, this study concluded the efficiency of the proposed design with the microbubbles technology thermally and hydrodynamically. key words: bioreactor, microbubble, airlift, computational model introduction climate change since the last century has become a matter of concern to the researchers [1]. despite of confirmed evidences that the main reason for this change is the use of fossil fuels as a major energy source, still global demand for this type of sources is rising. carbon dioxide, as one of gases that produced from this source, is considered as a driving factor in that observed climatic change [2]. university of baghdad college of engineering iraqi journal of chemical and petroleum engineering mailto:mkh_control@yahoo.com heat transfer and hydrodynamic in internal jacket airlift bioreactor with microbubble technology 36 ijcpe vol.18 no.4 (dec. 2017) -available online at: www.iasj.net there are many alternatives to address the problems of fossil fuels and environmental friendly as well [3,4]. however, and according to the available scientific possibilities, finding the main alternative to this source in the production of energy may be difficult and unreasonable [5]. in fact, the problem is not in the quality, but in their quantity and high cost of the production. fuel produced from the biomass via the microorganisms is a promising source to change this scenario[5], especially if it produced from food waste or inexpensive materials [6-8]. the operational conditions of these biological processes play an important role in improving the productivity such as the temperature [9-12], since the metabolic activities of microorganisms increase with increasing the temperature [12,13]. thus the temperature has an effective role in enhancing the consumption of organic matter and improving the production of biofuels. production of clean energy that can be obtained from thermophilic processes is more than obtained from mesophilic process, such as anaerobic digestion process [14-16]. however, the energy required in such a process may be the main impediment to be at the forefront of the promising sources in the production of renewable energy. in addition, the nature of the biological medium contributes in the complexity of variables during design of bioreactors, since these mediums usually contain solids, liquid and gas in the same time. each of these phases requires a basic understanding of the mixing patterns to provide a suitable environment for living microorganisms as well as to get their food taking account the operational conditions such as temperature and prevent the problem of thermal stratification. in summary, success of any biological process depends on the efficiency of the bioreactor in the hydrodynamic, mass transfer and heat transfer aspects. as known, the airlift bioreactor has operational and economic advantages in biological applications over other conventional bioreactors, such as simple construction with low cost in manufacturing and maintenance, sufficient mixing and lower shear stress to microorganisms cells[17-19]. although of many attempts in developing this type of bioreactors (as a design or enhancement of operational conditions) [20-22], there still remain a big challenge due to nature of biological mediums. thus, a deep knowledge of the fluid flow pattern and heat transfer inside the bioreactor is required for enhancement of metabolic activities of microorganisms or biomass productivity [23-26]. this research is a serious attempt that aims to reduce the energy consumed in bioreactors through the integration of ring diffuser and internal jacket draft tube in the proposed design. this investigation is done by studying the momentum and heat transfer throughout the proposed bioreactor with microbubbles technology. computational model the modelling of the process was carried out using comsol multiphysics with two-dimension and axial symmetry. fig.1 shows threedimension and two-dimension sketch of the suggested design of bioreactor used in the present study. laminar flow model was considered to simulate the airlift bioreactor using navier-stokes equation: … (1) mahmood k. h. al-mashhadani -available online at: www.iasj.net ijcpe vol.18 no.4 (dec. 2017) 37 where , , , , , ,and are liquid volume fraction (m 3 / m 3 ), density of liquid, velocity of liquid phase (m/s), time (sec), pressure (pa), dynamic viscosity (pa.s) and the gravity(m/s 2 ) respectively. the second model that was used in this current study was heat transfer model: … (2) fig.1, two and three-dimension sketch of bioreactor that suggested in this study where heat capacity [j/(mol k)], heat source/sink [w], heat loss [w], heat conductivity [w/(m k)], t temperature [k], and pressure work [j]. a time-dependent momentum balance model and heat transfer model were calculated in this model. for low gas concentration, the was pointed to zero as considered in the present model. the equation of gas phase was also used in present model with assumption that no mass transfer occurs between the two phases (gas and liquid). therefore the equation was equalled to zero: ( ) … (3) where , , and are the density of gas phase (kg/ m 3 ), gas volume fraction (m 3 / m 3 ), and velocity of gas respectively. the liquid volume fraction was calculated by . the gas velocity can be determined as + , since is relative velocity between two-phase fluid (gas and liquid). the was calculated from pressure drag that is balanced with pressure forces according to the following equation [27]: | | … (4) no-slip boundary condition was used on the draft tube and ring diffuser, while slip boundary condition was considered at the top of the liquid. extra fine mesh with 2141 elements was used in the present model. the general operational conditions that used in this research are illustrated throughout table 1. heat transfer and hydrodynamic in internal jacket airlift bioreactor with microbubble technology 38 ijcpe vol.18 no.4 (dec. 2017) -available online at: www.iasj.net table 1, operation conditions used in the computation model operational conditions for computational model parameter value unit temperature of gas 20 °c temperature of jacket 50 °c pressure of process 101 kpa gas mass flux 0.000754 kg/m 2 .s in fact, dealing with these kinds of models with time-dependent requires very high quality processor to complete the task of two dimensions model. therefore, and to compute these complex models, the present study used an official software package of computational model with a special system and high quality that were provided by the university of sheffield, uk. the dead zones in airlift bioreactor have investigated by al-mashhadani [27]. according to their results, decreasing the bubble size decreases the dead regions. however, reducing the bubble size, in spite of its advantages, may be undesirable in some biological applications because it causing separation of microorganisms or their nutrients by floatation process. then this will lead to failure of the process. therefore, 100 microns were considered in the present study. while the bubbles diameter of 1 mm and 0 micrometer were used for compression. results and discussion hydrodynamic study in the present study, the suggested design was examined through two aspects; hydrodynamic and heat transfer aspects. gas fractions, velocity of re-circulation liquid and volume of dead regions are main objective variables that were investigated for hydrodynamic study. while the temperature of the liquid, internal heat flux were addressed for heat transfer section.fig. 2 shows the gas-holdup in the downcomer region of the reactor at the bubble diameter of 100 micron and 1 mm. it can be seen that the existence of bubbles of 100 microns is more than that with 1 mm. for example the gas volume fraction of microbubble in the downcomer region is 0.0063, while with fine bubble diameter is 6.89e-12. thus, the retention time of small bubbles increases in this unsparged region, allowing greater exchange between the gas and liquid phases across the interfacial layers depending on the known principles of materialheat transfer. fig. 3 shows the snapshots of gas volume fraction at different bubble size after 12 min (i.e after steady state). this figure demonstrated that bubble size is critical factor in the design of bioreactor. in fact, the weak buoyancy force of small bubble size (i.e 100 microns) is sufficient to present such bubbles in downcomer region. however, the velocity of liquid circulation around the draft tube of reactor plays an important role in determining the amount of gas in this unsparged region as a result of the competition between the flow force of the liquid to that area and buoyancy of bubbles. fig. 2, gas volume fraction in the down-comer region mahmood k. h. al-mashhadani -available online at: www.iasj.net ijcpe vol.18 no.4 (dec. 2017) 39 therefore, it is possible to observe that the biggest amount of bubbles present in the down-comer region was in the first 3 minutes, due to the primary velocity of the circulation liquid in the riser region of the reactor and in this time as can be shown in fig. 4. then the steady state of gas holdup and velocity of liquid begin. fig. 3, gas volume fraction at different bubble size a) at 100 micron, b) at 1mm fig. 4, liquid velocity in the riser region of bioreactor fig. 5 illustrates the fluid flow pattern at 0.1, 2, and 5 min when the bioreactor is sparged with 100 micrometer. the figure indicates that the change was generated at the first moments of operation, after which, the liquid flow appeared to be stabilized. this stability resulted in homogeneity of the fluid in all parts of the bioreactor, especially after the second minute of simulation time. in general, the biological processes use domestic and industrial wastes as main biological media. these wastes usually are heavy because they containing the suspended solids. in addition, the biological reactions, naturally, are very slow, thus, sedimentation of these wastes at the bottom of traditional bioreactors is possible. even if sediments are already not present in the biological medium, the biomass generated by the biological reactions will form a sediment component during cultivation, as in algal cultivation. this will cause inhomogeneity in the temperature and ph as well as the famine in those layers of sediments due to separation from the suspended nutrients. fig. 5, snapshot of liquid velocity at 0.1, 2, and 5 min the best solution may be to place the diffuser at the bottom of the reactor, thus preventing the suspended material from precipitation. heat transfer and hydrodynamic in internal jacket airlift bioreactor with microbubble technology 40 ijcpe vol.18 no.4 (dec. 2017) -available online at: www.iasj.net but if the waste contains large particles, with time they will cause blockage in the diffuser. almashhadani [27] has noticed this problem by putting the diffuser at a height of 5 cm from the bottom to ensure that this problem does not occur. however, they reported that the volume dead zoon may be generated at the bottom of the reactor. the study takes into account the most likely problems by placing the diffuser 5 cm from the bottom of the reactor, but using a circular diffuser instead of disk diffuser and with a specific design as can be shown in fig. 6 .this construction allows the fluid to flow vigorously in that area to prevent formation of dead areas. in addition, and although, the present study suggested to use the microbubbles to increase momentum, heat, and mass transfer rate, the potential for foaming and stabilized emulsions in the reactor is a significant negative potential and it is one of the challenges facing the production of microbubbles as well as if is considered undesired property in many applications. previous studies have addressed this problem, and showed that decrease the bubbles size increases the height of foam [28]. fig.6, schematic of integration of ring diffuser and internal jacket draft tube the current study also took into account these problems and it sought to get an appropriate design to help using advantage of the microbubbles and reduce the problems resulting from the use of such technology. effect of foam, for example, can be reduced through increasing the circulation of the liquid around the draft tube in the bioreactor. although, the velocity of the liquid may be somewhat slow in the upper part of the downcomer of reactor it is unable to address the problem as can be seen in fig.7. this velocity increases as the liquid moves down the reactor. in fact, the proposed geometry of current reactor has greatly contributed in improving the liquid speed at the bottom. this figure shows the velocity of the liquid at different areas of the reactor. it can be observed that there is a significant increase in fluid velocity. this result will greatly contribute to move the biological sediments formed at the bottom of the reactor with great uniformity in temperature and ph. therefore, and according to these figures, the dead areas will be very few if not vanished in this suggested design. fig. 7, liquid velocity at different positions of reactor, a) in the downcomer (0.08, 0.14), b) in the bottom of reactor (0.04, 0.03), in the center ring of diffuser (0, 0.06) mahmood k. h. al-mashhadani -available online at: www.iasj.net ijcpe vol.18 no.4 (dec. 2017) 41 however, the microbubbles size can play an important role in determining liquid velocity, the increase in the central velocity of liquid during the reactor’s length is observed in fig. 8. this behaviour is due to the high momentum of the microbubbles to push the liquid up or down causing a decrease in the pressure and density of the mixture, which helps in generating high flux of the fluid due to momentum transfer between gas and liquid. fig. 8, liquid velocity along the bioreactor heat transfer study the effect of bubble size on the suggested design in heat transfer aspect was also investigated in this section. this factor represents the fundamental step in increasing the metabolic processes of microorganisms. traditional heating methods for biological processes have some disadvantage such as formation different thermal layers in the same reactor, and thus will affect the microorganisms. the current design is radically different from what was done in these attempts through fig. 6, which shows schematic diagram of suggested part in bioreactor by integrating the ring diffuser with internal draft jacket. from this integration, the moving of the gas and liquid upwards generates driving force in inner side of jacket draft tube. this force has sufficient power to remove the thermal thin layers, which are generated on the internal jacket during heat transfer process, thus, reduces the formation of the thermal resistance in this part of reactor. removing this layer creates an environment suitable for more heat transfer rate. in other words, decreasing the thermal layer thickness increases the heat transfer rate if the process was under sparging system. fig. 9 shows simple schematic diagram of removal and generation of thermal layer during sparging system. at time equal zero (no bubbling system), the thermal layer is already generated. when the sparging system starts, the created layer will be removed. thus more heat will transfer due to decreasing the thermal resistance. fig.9, schematic diagram of removal the thermal layer by bubbling system the influence of the bubble sizes on the heat transfer rate in the current design was also considered. fig. 10 displays the temperature response in the two reactor areas (downcomer and riser region) for 12 min until the steady state is achieved. heat transfer and hydrodynamic in internal jacket airlift bioreactor with microbubble technology 42 ijcpe vol.18 no.4 (dec. 2017) -available online at: www.iasj.net it is noted that the temperature in the first zone is higher than that in the second zone as well as the fastest up to the steady state. the main reason for this change is the amount of internal heat transferred from the riser region to downcomer region as a result of the momentum transfer generated by sparging process. this behaviour demonstrates a real integration between air bubbles and the liquid that work together in heat transfer process. therefore it is a significant delay in the temperature response in the downcomer region due to delay the recirculation of the liquid and gas between the two areas. figure 11 shows snapshot of transfer of internal energy from the riser region to downcomer region at 0.1 min, 5 min and 8 min. however, determining the temperature difference between these two regions depends largely on the diameter of the micro bubbles. figure 12 shows that the temperature and speed of access to the steady state is almost very simple change between the two regions, while with no bubbling process, there was no observed change in temperature at any region. fig.10, temperature profile in riser and downcomer region at 100 micron bubble size fig. 11, internal energy in the suggested bioreactor at different simulation time; 0.1, 5, and 8 min. the last number was taken as value at steady state situation fig. 12, temperature profile in riser and down-comer region at 1mm bubble size figure 13 illustrates temperature profile in unsparged area (downcomer region) at different bubble size; 1mm, 100 and 0 micrometer. it can be seen from this figure that the flow, whatever its velocity is better than the flow without a bubbles, due to improved temperature, speed and homogeneity. however, microbubbles give great heat efficiency compared to large bubbles, not by the high speed of heat transfer alone but with improving the features of the hydrodynamic. mahmood k. h. al-mashhadani -available online at: www.iasj.net ijcpe vol.18 no.4 (dec. 2017) 43 fig. 13, temperature profile in downcomer region at 1 mm, 100, and 0 micron bubble size conclusions current research addressed the hydrodynamic and heat transfer study of the proposed reactor design using laminar bubbling flow model and heat transfer model in internal jacket airlift bioreactor. through the integration of these two models, the results indicated the importance effect of microbubbles on the main variables in biological processes such as retention time and mixing system. this will harmonize with the operating conditions in the process to get the equitable distribution of nutrients and prevent the formation of dead areas. in terms of the study of heat transfer, bubbles are important factor in the efficiency of heat transfer. however, reducing the bubble diameter increases the frequency of the temperature response and reaching the steady state quickly. acknowledgment the author would like to thank prof. william b. zimmerman from the university of sheffield, united kingdom and prof. steven wilkinson from chester university, united kingdom for their support for providing the official software package and information. he would like also to acknowledge the support of dr. hemaka bandalusena (loughborough university, united kingdom). the author would like to thank the university of baghdad-department of chemical engineering. references 1dryzek, j. s., norgaard, r. b. and schlosberg, d. 2011. the oxford handbook of climate change and society: approaches and responses oxford university press inc., new york. chapter one. 2schenk, p. m., thomas-hall, s. r., stephens, e., marx, u. c., mussgnug, j. h., posten, c., kruse, o. and hankamer, b. 2008. second generation biofuels: highefficiency microalgae for biodiesel production. bioenergy research, 1, 20-43. 3singh, v. 2012. effect of corn quality on bioethanol production. biocatalysis and agricultural biotechnology, 1, 353-355. 4scott, s. a., davey, m. p., dennis, j. s., horst, i., howe, c. j., leasmith, d. j. and smith, a. g. 2010. biodiesel from algae: challenges and prospects. current opinion in biotechnology, 21, 277-286. heat transfer and hydrodynamic in internal jacket airlift bioreactor with microbubble technology 44 ijcpe vol.18 no.4 (dec. 2017) -available online at: www.iasj.net 5chisti, y. 2007. biodiesel from microalgae. biotechnology advances, 25, 294-306. 6montgomery, l. f. and bochmann, g. 2014. pretreatment of feedstock for enhanced biogas production. iea bioenergy, 1-20. 7castellucci, s., cocchi, s., allegrini, e. and vecchione, l. 2013. anaerobic digestion and codigestion of slaughterhouse wastes. journal of agricultural engineering, 44, 526-530. 8de wit, m., junginger, m., lensink, s., londo, m. and faaij, a. 2010. competition between biofuels: modeling technological learning and cost reductions over time. biomass and bioenergy, 34, 203217. 9fraser, t. and brown, p. d. 2017. temperature and oxidative stress as triggers for virulence gene expression in pathogenic leptospira spp. frontiers in microbiology,8. 10capson-tojo, g., torres, a., muñoz, r., bartacek, j. and jeison, d. 2017. mesophilic and thermophilic anaerobic digestion of lipid-extracted microalgae n. gaditana for methane production. renewable energy, 105, 539-546. 11tian, z., zhang, y., li, y., chi, y. and yang, m. 2015. rapid establishment of thermophilic anaerobic microbial community during the one-step startup of thermophilic anaerobic digestion from a mesophilic digester. water research, 69, 9-19. 12donoso-bravo,a., retamal, c., carballa, m., ruiz-filippi, g. and chamy, r. 2009. influence of temperature on the hydrolysis, acidogenesis and methanogenesis in mesophilic anaerobic digestion: parameter identification and modeling application. water science and technology, 60, 9-17. 13ahring, b. k., ibrahim, a. a. and mladenovska, z. 2001. effect of temperature increase from 55 to 65 degrees c on performance and microbial population dynamics of an anaerobic reactor treating cattle manure. water research, 35, 24462452. 14waqas, m., almeelbi, t. and nizami, a.-s. 2017. resource recovery of food waste through continuous thermophilic in-vessel composting. environmental science and pollution research, 1-11. 15riggio, s., hernandéz-shek, m., torrijos, m., vives, g., esposito, g., van hullebusch, e., steyer, j. and escudié, r. 2017. comparison of the mesophilic and thermophilic anaerobic digestion of spent cow bedding in leach-bed reactors. bioresource technology, 234, 466-471. 16budzianowski, w. m. 2012. sustainable biogas energy in poland: prospects and challenges. renewable and sustainable energy reviews, 16, 342-349. 17denis, b., pérez, o. a., lizardi-jiménez, m. a. and dutta, a. 2017. numerical evaluation of direct interfacial uptake by a microbial consortium in an airlift bioreactor. international biodeterioration and biodegradation, 119, 542-551. 18asadi, a., zinatizadeh, a. a. and van loosdrecht, m. 2016. a novel continuous feed and intermittent discharge airlift bioreactor (cfidab) for enhanced simultaneous removal of carbon and nutrients from soft drink industrial wastewater. chemical engineering journal, 292, 13-27. mahmood k. h. al-mashhadani -available online at: www.iasj.net ijcpe vol.18 no.4 (dec. 2017) 45 19cozma, p. and gavrilescu, m. 2012. airlift reactors: applications in wastewater treatment. environmental engineering and management journal, 11, 15051515. 20hernández-calderón oscar, m., gonzález-llanes marcos, d., riosiribe erika, y., jiménez-lam sergio, a., chavez-parga ma.del, c. and escamilla-silva eleazar, m. 2017. hydrodynamics and mass transfer simulation in airlift bioreactor with settler using computational fluid dynamics. international journal of chemical reactor engineering. 21soman, a. and shastri, y. 2015. optimization of novel photobioreactor design using computational fluid dynamics. applied energy, 140, 246-255. 22huang, q., yang, c., yu, g. and mao, z.-s. 2010. cfd simulation of hydrodynamics and mass transfer in an internal airlift loop reactor using a steady twofluid model. chemical engineering science, 65, 5527-5536. 23karaeva, j. v. and khalitova, g. r. 2015. evaluation of mixing quality in anaerobic digester. 7, 112. 24lestinsky, p., vecer, m., vayrynen, p. and wichterle, k. 2015. the effect of the draft tube geometry on mixing in a reactor with an internal circulation loop – a cfd simulation. chemical engineering and processing: process intensification, 94, 29-34. 25baudez, j. c., ginisty, p., peuchot, c. and spinosa, l. 2007. the preparation of synthetic sludge for lab testing56 (9) 67-74. 26dursun, d., ayol, a. and dentel, s. k. 2004. physical characteristics of a waste activated sludge: conditioning responses and correlations with a synthetic surrogate. water science and technology, 50, 129-136. 27al-mashhadani mkh, wilkinson, s. j. and zimmerman, w. b. 2015. airlift bioreactor for biological applications with microbubble mediated transport processes. chemical engineering science, 137, 243-253. 28prud’homme r. k. and khan s. a., 1996. foams, theory, measurements, and applications. surfactant science series, volume 57. pp 146-151 available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.21 no.1 (march 2020) 9 – 41 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: bariq bahmman jima, email: drbarikbahman93@gmail.com , name: najwa saber majeed, email: majeednajwa@gmail.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. oxidation desulphurization of heavy naphtha improved by ultrasound waves bariq bahmman jima and najwa saber majeed university of baghdad, chemical engineering dept. abstract the oxidation desulphurization assisted by ultrasound waves was applied to the desulphurization of heavy naphtha. hydrogen peroxide and acetic acid were used as oxidants, ultrasound waves as phase dispersion, and activated carbon as solid adsorbent. when the oxidation desulphurization (ods) process was followed by a solid adsorption step, the performance of overall sulphur removal was 89% for heavy naphtha at the normal condition of pressure and temperature. the process of (ods) converts the compounds of sulphur to sulfoxides /sulfones, and these oxidizing compounds can be removed by activated carbon to produce fuel with low sulphur content. the absence of any components (hydrogen peroxide, acetic acid, ultrasound waves and activated carbon) from the ods process leading to reduce the performance of removal, hydrogen peroxide was the most crucial factor. the ultrasound waves increase the dispersion of carbon, water and oil phase, promotes the interfacial mass transfer, and this leads to accelerates the reaction. the ultrasound waves did not affect the chemical or physical properties of the fuel. the chemical analysis of treated fuel oil showed that <1% of the hydrocarbon fuel compounds were oxidized in the ods process. in this work, desulphurization by oxidation is the main mechanism was tested with several parameters that effects desulphurization efficiency such as sonication time (5-40) min, activated carbon (0.01-0.5) gm, hydrogen peroxide (1-30) ml, and acetic acid (1-15) ml. it was found that the hydrogen peroxide amounts lead to increase oxidation rates of sulphur compounds so, the desulphurization efficiency increases. the optimum amounts of oxidants are 10 ml hydrogen peroxide per 100 ml of heavy naphtha. increasing the amount of acid catalyst lead to increase sulphur removal, it was found that7.5 ml acid per 10 ml oxidant was the optimum amount. activated carbon as a solid adsorbent and reaction enhancer with 0.1gm weight was found as the optimum amount for 100 ml heavy naphtha. increasing sonication time lead to increase desulphurization rate, it was found that (10 min) is the optimum period. by applying the optimum parameters 89% of sulfur can be removed from heavy naphtha with 598.4 ppm sulphur content. keywords: ultra-low sulphur fuel, oxidative desulfurization, ultrasonic waves, hydrogen peroxide, acetic acid received on 23/04/2019, accepted on 03/09/2019, published on 30/03/0220 https://doi.org/10.31699/ijcpe.2020.1.0 1introduction sulphur compounds in oil fractions are the main reason for many environmental pollution and equipment failure. the presence of sulfur compounds with a high concentration in oil fraction lead with time to damage industrial equipment by causing corrosion effect ‎[1]. sulfur compounds are poison metals and catalysts used in industrial processes such as catalytic cracking and catalytic reforming by precipitation on the catalyst surface and close its pores ‎[2]. burning of oil fractions that contain a high concentration of sulphur compounds lead to releases of sulphur oxides gases (sox) which cause smog and acid rains so that for environmental protection called for diminishing sulphur compounds content to minimum concentration as much as probable by using suitable desulfurization processes ‎[3]. hydrodesulphurization (hds) is the conventional desulphurization process, it is a familiar practice in the refinery for several years and has the dominance of preexistent in the infrastructure of the refinery, but this process required high pressure and temperature ‎[4]. seek for preference way to sulphur component removal has been increased in the past years ‎[5]. the selective oxidation of organic sulphur compounds at ambient pressure and room temperature in the process of oxidation desulphurization (ods), permit the utilize of inexpensive adsorbents to get low sulphur content ‎[6]. the challenge in oxidation desulphurization (ods) is to recognize the conditions that perform ultra-deep desulphurization without using expensive catalysts or auxiliary chemicals and keep high fuel oils recovery ‎[7]. ultrasonic waves used to raise quick reactions by dissipating the multiphase admixtures of the oil phase and aqueous phase. the oxidation process modifies the physical properties of organic sulphur compounds so that these compounds can be removed by adsorption using inexpensive adsorbent ‎[8]. the moderates condition used in the ods process reduces the total energy required for sulphur removal in comparisons with the hds process ‎[9]. https://doi.org/10.31699/ijcpe.2020.1.2 b. b. jima and n. s. majeed / iraqi journal of chemical and petroleum engineering 21,1 (2020) 9 14 01 oxidation desulphurization considered an efficient process to remove sulphur compounds that can't be removed by the hds process such as benzothiophenes and dibenzothiophenes compounds ‎[10]. this study is a first attempt to treat commercial heavy naphtha supplied from al-doura refinery to remove sulphur content by the oxidation process improved by ultrasound waves. the effect of several variables on the process was studied, such as the effect of hydrogen peroxide, acetic acid, sonication time and activated carbon as adsorbent. 2experimental work 2.1. materials chemical materials utilized in this research are shown in table 1, the activated carbon used in this work is of 1184.9 m2/gm surface area. heavy naphtha of 598.4 ppm sulphur content was derived from al-doura refinery with 60.7 api and a density of 0.7379 g/cm3. table 1. chemical materials utilized in experiment work chemical materials function molecular weight purity % formula company hydrogen peroxide oxygen source 34 50 h2o2 hopkin and williams, england acetic acid increase oxidation 60 99 c2o2h4 riedel-de haen activatedcarbon solid adsorbent 12.01 ---- c jacobi carbons 2.2. apparatus the equipment used is as follows: a-q 500 sonicator q 500 sonicator is the important apparatus employed in these experiments, fig. 1 ultrasound device. it is a strong device for ultrasound wave's processor displaying programmable action and numerical show of running parameters. q500 sonicator is of 20 khz and 500 w maximum amplitude of power ultrasound. the device is designed and produced by the company of materials and sonics, inc. model vx 500, newton, united states). fig. 1. ultrasound device of q 500 sonicator bhot plate magnetics stirrer manufactured by pce americas inc., usa. 2.3. analysis sulphur content of heavy naphtha was obtained due to astm d-7093 by utilizing the antek-multitek device located in al-daura refinery, manufactured by (pac lp, houston, texas, usa). 2.4. procedure 100 ml of heavy naphtha with 598.4 ppm sulphur content put in a beaker, as oxidative agent amounts of hydrogen peroxide(h2o2) (1-30 ml) and as a catalyst amounts of acetic acid (1-15 ml) and activated-carbon (0.01-0.5 gm) as adsorbent, were added to this beaker. this beaker put in ultrasound effects for periods (5-40 min) of time with amplitudes (20-60% amp) of power ultrasound. after the sonication process, the mixture put up in a magnetic stirrer for 1 hr. with 900 rpm to satisfy adsorption equilibrium ‎[11], then the oil phase and aqueous phase separated and the oil phase went to analysis to know sulphur content by the antek-multitek device. 3results and discussion 3.1. effects of hydrogen peroxide amount the effects of changing hydrogen peroxide added amount on desulphurization of heavy naphtha are shown in fig. 2. fig. 2. effects amounts of oxidant on sulphur content for 100 ml of heavy naphtha, 10 min sonication time, 20% amp ultrasound power, 0.1 gm activated carbon and 1ml acid. note: amp means amplitude as shown in fig. 2, the desulphurization efficiency increases with increasing amounts of oxidant hydrogen peroxide, this is because of increasing the free radicals in the mixture which leads to increase oxidation of sulphur compounds, this behavior was also pointed out by hosseini, 2012, ‎[12]. b. b. jima and n. s. majeed / iraqi journal of chemical and petroleum engineering 21,1 (2020) 9 14 00 the optimum volume of hydrogen peroxide is 10 ml, for this reason, all subsequent experiments are selected at hydrogen peroxide volume 10 ml hydrogen peroxide per 100 ml of naphtha. 3.2. effects of acetic acid amount the effects of changing the amounts of acetic acid on desulphurization process are shown in fig. 3. fig. 3. effects amount of acid on sulphur content for 100 ml heavy naphtha, 10 ml hydrogen peroxide, 10 min sonication time, 20% amp power ultrasound and 0.1 gm activated carbon as shown in fig. 3, increasing the amounts of acid catalyst lead to increase the removal of sulphur until 7.5 ml of acid that is because beyond this amounts adverse reaction occurs, this behavior was due to the reaction between oxidant and acid. … (1) the reaction of hydrogen peroxide and acetic acid produces peracetic acid. this acid is a form of proxycarboxylic acids, that can decompose to produce hydroproxy radicals ( .ooh), these radicals are more effective than hydroxyl radicals (.oh) formed from hydrogen peroxide decomposition, so oxidation process increases. it was found that the best sulphur removal when utilized 7.5 ml acetic acid per 10 ml hydrogen peroxide. the optimum ratio of acid to oxidant is 0.75, for this reason, all subsequent experiments are selected at acid to oxidant ratio of 0.75. fig. 4. the relation between sulphur content and sonication time for 100 ml naphtha, 10 ml hydrogen peroxide, 7.5 ml acetic acid, 20% amp of ultrasound power and 0.1 gm activated carbon as shown in fig. 4, increasing the sonication time leads to an increase in the oxidation of sulphur compounds due to increasing exposure periods of these compounds to the oxidants, then increasing desulphurization rate. these longer times of reaction under the energy of ultrasound lead to strong cavitation formation that leads to fine emulsions formation for the oxidation reaction, this fine emulsion increase contacts and exposure of the oxidative system to organic sulphur compounds, so increase desulphurization efficiency. these results are in good agreement with that of teng-chien chen., et al 2010, ‎[13]. the optimum period of sonication time is 10 min, for this reason, all experiments are selected at 10 min sonication time. 3.4. effects of activated carbon amounts the results related to satisfying these effects are shown in fig. 5 fig. 5. sulphur content with different amounts of activated carbon for 100 ml heavy naphtha, 10 min sonication time, 20% amp ultrasound power, 10 ml hydrogen peroxide and 7.5 ml acetic acid b. b. jima and n. s. majeed / iraqi journal of chemical and petroleum engineering 21,1 (2020) 9 14 01 as shown in figure 5, the increase of activated carbon amounts leads to increase desulphurization efficiency due to increased oxidation rates by increase attractions the organic sulphur compounds to the aqueous phase where oxidation occurs, this behavior was also pointed out by gonzalez., et al 2012, ‎[8]. the optimum amount of activated carbon is 0.1 gm so that all experiments are selected at 0.1 gm activated carbon. 4conclusion based on the results obtained, the conclusions can be demonstrated as follows: it was found that increasing hydrogen peroxide amounts lead to an increased oxidation rate, so desulphurization efficiency increases. the ultrasound-assisted oxidative desulphurization process with adsorption by active carbon has high effects on desulphurization of crude oil fractions up to 89 % for heavy naphtha. the amounts of acetic acid used in this process have an optimum value, if more than the optimum value, the adverse reaction will occur leading to decrease the efficiency of desulphurization, 7.5 ml acetic acid per 10 ml of hydrogen peroxide is the optimum value of acetic acid in this work. increasing the time of sonication lead to increase sulphur removal, but using too much time leads to increase in the cost of operation, it was found that the optimum sonication time for heavy naphtha is 10 min. increasing amounts of active carbon lead to increase adsorption rate but at 0.5 gm ≥ the amount becomes too much, so the favorite amount for 100 ml heavy naphtha is 0.1 gm. the process is done without any effects in the chemical or physical properties of the fuel. references [1] rawnaq b. jimaa, zaid h. mahmoud, farah k. ali., 2018. evaluation the efficiency of cufe2o4 prepared photolysis by osd and photo degradation., entomol. appl. sci. lett., 2018, 5 (2) pp.91-100. [2] a. shamseddini, f. esmaeilzadeh and d. mowla., 2017. diesel oil upgradation by ultrasound irradiation: a study on the effects of main operational parameters. phys. chem. res., vol. 5, no. 4, 691-707, december 2017. [3] zhu w., zhu g., li h., chao y., chang y., chen g. & han c., 2011. oxidative desulfurization of fuel catalyzed by metal-based surfactant-type ionic liquids. “journal of molecular catalysis. a, chemical”, 347, pp.8–14. [4] abdul-halim a. mohammed and zeinab k. nassrullah, 2013. preparation and formation of zeolite 5a from local kaolin clay for drying and desuphurization of liquefied petroleum gas. " iraqi journal of chemical and petroleum engineering", vol.14 no.1 (march 2013) 113. [5] campos-martin j.m., capel-sanchez m. c., perezpresas p., fierro j. l. g., 2010. oxidative processes of desulfurization of liquid fuels. journal of chemical technology and biotechnology, 85(7), pp.879–890. [6] iman najafi, mohammad amin makarem, mahmood amani., 2011., application of ultrasound waves to increase the efficiency of oxidative desulfurization process., advances in petroleum exploration and development, 2(2), 63-69. [7] mello p.a., duarte f.a., and nunes m. g., 2009, ultrasound-assisted oxidative process for sulfur removal from petroleum product feedstock, ultra son. sonochem journal. vol.16, pp. 732-736. [8] lino a. gonzalez, peter kracke, william h. green, jefferson w. tester, linda m. shafer, and michael t. timko., 2012. oxidative desulfurization of middledistillate fuels using activated carbon and power ultrasound. cambridge, massachusetts 02139, united states. energy fuels 2012, 26, 5164−5176. [9] nada sadoon ahmedzeki and arowa salah alddin mahdi, 2014. research octane number improvement of iraqi gasoline by adsorption of n-paraffins using zeolite molecular sieves, "iraqi journal of chemical and petroleum engineering", vol.15 no.2 (june 2014) 2737. [10] safa nabeel abdulqahar, majid i. abdulwahab and khalid k. hummadi., 2019. reuse of spent hydrotreating catalyst of the middle petroleum fraction. "iraqi journal of chemical and petroleum engineering", vol.20 no.1 (march 2019) 15 – 22. [11] kinya sakanishi, hamdy farag, shinya sato, akimitsu matsumura, and ikuo saito., 2003., adsorptive removal of sulfur compounds from naphtha fractions by using carbon adsorbents, "national institute of advanced industrial science and technology". [12] h. hosseini., 2012. novel methods for desulfurization of fuel oils., department of chemical engineering, abadan branch, islamic azad university, abadan, iran., world academy of science, engineering and technology, vol:6, no:11, 2012. [13] teng-chien chen, yun-hwei shen, wen-jhy lee, chih-chung lin, meng-wei wan., the study of ultrasound-assisted oxidative desulfurization process applied to the utilization of pyrolysis oil from waste tires. journal of cleaner production 18 (2010) 18501858. https://www.researchgate.net/profile/zaid_hamid2/publication/328631683_evaluation_the_efficiency_of_cufe2o4_prepared_photolysis_by_osd_and_photo_degradation/links/5bd9908492851c6b279bcb86/evaluation-the-efficiency-of-cufe2o4-prepared-photolysis-by-osd-and-photo-degradation.pdf https://www.researchgate.net/profile/zaid_hamid2/publication/328631683_evaluation_the_efficiency_of_cufe2o4_prepared_photolysis_by_osd_and_photo_degradation/links/5bd9908492851c6b279bcb86/evaluation-the-efficiency-of-cufe2o4-prepared-photolysis-by-osd-and-photo-degradation.pdf https://www.researchgate.net/profile/zaid_hamid2/publication/328631683_evaluation_the_efficiency_of_cufe2o4_prepared_photolysis_by_osd_and_photo_degradation/links/5bd9908492851c6b279bcb86/evaluation-the-efficiency-of-cufe2o4-prepared-photolysis-by-osd-and-photo-degradation.pdf https://www.researchgate.net/profile/zaid_hamid2/publication/328631683_evaluation_the_efficiency_of_cufe2o4_prepared_photolysis_by_osd_and_photo_degradation/links/5bd9908492851c6b279bcb86/evaluation-the-efficiency-of-cufe2o4-prepared-photolysis-by-osd-and-photo-degradation.pdf http://www.physchemres.org/m/&url=http:/www.physchemres.org/article_48979.html http://www.physchemres.org/m/&url=http:/www.physchemres.org/article_48979.html http://www.physchemres.org/m/&url=http:/www.physchemres.org/article_48979.html http://www.physchemres.org/m/&url=http:/www.physchemres.org/article_48979.html http://www.physchemres.org/m/&url=http:/www.physchemres.org/article_48979.html https://www.sciencedirect.com/science/article/abs/pii/s1381116911002755 https://www.sciencedirect.com/science/article/abs/pii/s1381116911002755 https://www.sciencedirect.com/science/article/abs/pii/s1381116911002755 https://www.sciencedirect.com/science/article/abs/pii/s1381116911002755 https://www.sciencedirect.com/science/article/abs/pii/s1381116911002755 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/302 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/302 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/302 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/302 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/302 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/302 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.2371 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.2371 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.2371 https://onlinelibrary.wiley.com/doi/abs/10.1002/jctb.2371 http://www.cscanada.org/index.php/aped/article/view/j.aped.1925543820110202.116 http://www.cscanada.org/index.php/aped/article/view/j.aped.1925543820110202.116 http://www.cscanada.org/index.php/aped/article/view/j.aped.1925543820110202.116 http://www.cscanada.org/index.php/aped/article/view/j.aped.1925543820110202.116 http://www.cscanada.org/index.php/aped/article/view/j.aped.1925543820110202.116 https://www.sciencedirect.com/science/article/abs/pii/s1350417709000418 https://www.sciencedirect.com/science/article/abs/pii/s1350417709000418 https://www.sciencedirect.com/science/article/abs/pii/s1350417709000418 https://www.sciencedirect.com/science/article/abs/pii/s1350417709000418 https://pubs.acs.org/doi/abs/10.1021/ef201289r https://pubs.acs.org/doi/abs/10.1021/ef201289r https://pubs.acs.org/doi/abs/10.1021/ef201289r https://pubs.acs.org/doi/abs/10.1021/ef201289r https://pubs.acs.org/doi/abs/10.1021/ef201289r https://pubs.acs.org/doi/abs/10.1021/ef201289r http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/275 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/275 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/275 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/275 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/275 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/275 https://doi.org/10.31699/ijcpe.2019.1.3 https://doi.org/10.31699/ijcpe.2019.1.3 https://doi.org/10.31699/ijcpe.2019.1.3 https://doi.org/10.31699/ijcpe.2019.1.3 https://doi.org/10.31699/ijcpe.2019.1.3 https://www.researchgate.net/publication/287767377_adsorptive_removal_of_sulfur_compounds_from_naphtha_fractions_by_using_carbon_adsorbents https://www.researchgate.net/publication/287767377_adsorptive_removal_of_sulfur_compounds_from_naphtha_fractions_by_using_carbon_adsorbents https://www.researchgate.net/publication/287767377_adsorptive_removal_of_sulfur_compounds_from_naphtha_fractions_by_using_carbon_adsorbents https://www.researchgate.net/publication/287767377_adsorptive_removal_of_sulfur_compounds_from_naphtha_fractions_by_using_carbon_adsorbents https://www.researchgate.net/publication/287767377_adsorptive_removal_of_sulfur_compounds_from_naphtha_fractions_by_using_carbon_adsorbents https://www.researchgate.net/publication/287767377_adsorptive_removal_of_sulfur_compounds_from_naphtha_fractions_by_using_carbon_adsorbents https://pdfs.semanticscholar.org/e7ef/e89248f27b495cc0a47f12bdc9c93917cb77.pdf https://pdfs.semanticscholar.org/e7ef/e89248f27b495cc0a47f12bdc9c93917cb77.pdf https://pdfs.semanticscholar.org/e7ef/e89248f27b495cc0a47f12bdc9c93917cb77.pdf https://pdfs.semanticscholar.org/e7ef/e89248f27b495cc0a47f12bdc9c93917cb77.pdf https://pdfs.semanticscholar.org/e7ef/e89248f27b495cc0a47f12bdc9c93917cb77.pdf https://pdfs.semanticscholar.org/e7ef/e89248f27b495cc0a47f12bdc9c93917cb77.pdf https://www.sciencedirect.com/science/article/pii/s0959652610002775 https://www.sciencedirect.com/science/article/pii/s0959652610002775 https://www.sciencedirect.com/science/article/pii/s0959652610002775 https://www.sciencedirect.com/science/article/pii/s0959652610002775 https://www.sciencedirect.com/science/article/pii/s0959652610002775 https://www.sciencedirect.com/science/article/pii/s0959652610002775 b. b. jima and n. s. majeed / iraqi journal of chemical and petroleum engineering 21,1 (2020) 9 14 02 الموجات فوق الصوتية أكسدة و إزالة الكبريت من النافتا الثقيمة المحسنة بواسطة بارق بهمان ونجوى صابر مجيد قسم اليندسة الكيمياويةجامعة بغداد, ألُخالصة تبعًا لزيادة ألطمب العالمي عمى أستخدام وقود أقل ظررًا بالبيئة وبأقل تكمفة ممكنة من ألجانب أالقتصادي, فأن ىذا ألعمل يركز عمى عممية كفوؤة وقميمة ألكمفة من أجل إزالة ألكبريت من وقود ألنفثا ألثقيمة عن طريق مركبات ألكبريت ألمعززة بالموجات فوق ألصوتية حيث أثبتت ىذه ألعممية كفائتيا في إزالة عميقة عممية أكسدة لممحتوى ألكبريتي. بأستخدام نظام أالكسدة ألمكون من بيروكسيد ألييدروجين وحامض ألخميك كعامل مساعد من أجل أكسدة إزالة أالخير بواسطة ألكاربون ألنشط.مركبات ألكبريت ألعضوية وتحويميا ألى سمفونات حيث تتم ألموجات فوق ألصوتية تزيد من ألمساحة ألسطحية لتالمس نظام االكسدة مع ألطور ألنفطي في ألنظام ثنائي ألطور وألتي تؤدي لزيادة معدل أالكسدة لمركبات ألكبريت وبالتالي زيادة كفائة أالزالة وبدون أي تأثير عمى فيزيائية لموقود.ألخواص ألكيميائية او أل في ىذا ألعمل ِإزالة ألكبريت بواسطة أالكسدة ىي ألعممية ألرئيسية وقد أختُبرت مع عدة متغيرات والتي تؤثر 04-04دقيقة(, مقدار طاقة ألموجات فوق ألصوتية ) 04-5في كفائة أإِلزالة وِمن ىذِه ألعوامل وقت ألتفاعل ) مل( 04-0غم(, كمية ألعامل ألمؤكِسد ىيدروجبن بيروكسيد ) 5..4-4.40%(, كمية ألكاربون ألمنشط ) مل(. 05-0وكمية حامض ألخميك ) في ما يتعمق بتأثير ألعامل ألمؤكسد فقد لوحظ أنو بزيادة كمية ألييدروجين بيروكسيد تؤدي لزيادة معدل إزالة ن أل مل من ألنفثا 044كمية ألُمناِسبة ِلمعالجة ألكبريت نظرًا ِلزيادة ُمعدل أالكسدة ِلمركبات ألكبريت ألعظوية وا مل من ىيدروجين بيروكسيد. 04ألثقيمة ىي مل من حامض 5..في ما يتعمق بتأثير حامض ألخميك فقد لوِحظ ِبأنُو يجب أن تكون كميتُو ُمحددة وىي لُمحددة تؤدي مل من ألييدروجين بيروكسيد حيُث أن زيادة كمية ألحامض أكثر من ألكمية أ 04ألخميك لكل ِلحصول تأثير عكسي وبالتالي تُقمل ِمن كفائة أإِلزالة لمكبريت. غم ِمن ألكاربون 4.0مل ِمن ألنفثا ىي 044ألكاربون ألمنشط كسطح ممتز وِجد أَن ألكمية ألُمناِسبة ل ألُمنشط. b. b. jima and n. s. majeed / iraqi journal of chemical and petroleum engineering 21,1 (2020) 9 14 03 ِجد أنُو أفضل فترة زمنية مناسبة زيادة وقت ألتعُرض ِلمموجات فوق ألصوتية يؤدي ِلزيادة ُمعدل أاِلزالة وقد و دقيقة( ِلُمعالجة ألنفثا ألثقيمة. 04ىي) % من ألمقدار ألُكمي ِلطاقة 04مقدار طاقة ألموجات فوق ألصوتية مؤثر ميم في ىذه ألعممية حيث ِوجد أنُو حالة أستخدام طاقة جياز ألموجات فوق ألصوتية ىو ألمقدار ألمناسب ِِلزالة ألكبريت ِمن ألنفثا ألثقيمة وفي أعمى َفإن ذلك يؤدي لحدوث تأثير عكسي يؤدي ِلتقميل َكفائة إزالة ألكبريت. % ِمن ألمحتوى ألكبريتي وذِلك عند تطبيق جميع 98عمى ُكِل حال فإنٌو أمكن ألحصول عمى إزالة تصل إلى ق ألصوتية إِلزالة ألكبريت من النفثا ألثقيمة إن تفاُعل أالكسدة ألمعززة ِبالموجات فو ألمقادير ألِمثالية ِلممتغيرات. ىوتفاعل من ألدرجة أِلولى. موجات فوق الصوتية ,أالكسدة ,: إزالة ألكبريتدالةالكممات ال iraqi journal of chemical and petroleum engineering vol.16 no.4 (december 2015) 4549 issn: 1997-4884 prediction of shear wave velocity for carbonate rocks wafa m. al-kattan petroleum engineering department, college of engineering, university of baghdad abstract in many oil fields only the bhc logs (borehole compensated sonic tool) are available to provide interval transit time (δtp), the reciprocal of compressional wave velocity vp. to calculate the rock elastic or inelastic properties, to detect gas-bearing formations, the shear wave velocity vs is needed. also vs is useful in fluid identification and matrix mineral identification. because of the lack of wells with shear wave velocity data, so many empirical models have been developed to predict the shear wave velocity from compressional wave velocity. some are mathematical models others used the multiple regression method and neural network technique. in this study a number of empirical models were considered to predict vs from vp. the models had been correlated and a general equation, based on statistical method, was established for carbonate rocks. the proposed equation, then, was examined using log data and good results observed. key words: shear wave velocity, elastic properties of rocks, sonic logs. introduction in the characterization of a hydrocarbon reservoir the estimation of the shear wave velocity, vs , is important in the determination of the mechanical properties of rocks, identification of gas bearing zones, and estimation of gas saturation. the standard practice is to derive vs, vp from testing rock samples in the laboratory. when shear wave velocity, vs, cannot be measured, it may be replaced with synthetic shear wave velocity computed from empirical models using compressional wave velocity. researchers have employed a variety of approaches, based on laboratory core analysis, well log interpretation, and numerical modeling to predict vs from vp. most of these studies have discussed sandstone formations. in order to predict a more comprehensive empirical model, for carbonate rocks, a number of models have been combined to determine one equation across them all. the predicted equation, then, examined using vs and vp data obtained from full-wave sonic logs and a useful qualitatively results have been achieved. iraqi journal of chemical and petroleum engineering university of baghdad college of engineering prediction of shear wave velocity for carbonate rocks 46 ijcpe vol.16 no.4 (dec. 2015) -available online at: www.iasj.net vp – vs relationships a good vs values can be predicted form the empirical relationships in similar formations, if all measurement are error free. in carbonate rocks, prediction of vs using vp is most reliable according to the compression of prediction with laboratory and logging measurements. pickett 1963, [1] demonstrated the potential of vp/vs as lithology indicator. his laboratory and field data for many different formations showed that measurements corresponding to limestone and dolomite were found along lines of constant but different ratios: vp/vs = 1.9 or vs = vp/1.9 ... (1) vp/vs = 1.8 or vs = vp/1.8 ... (2) where equation (1) for limestone and (2) for dolomite. he, also, demonstrated that vs is 2-5 times more sensitive to variation in porosity than vp in limestone. vp in limestone was found to be the least sensitive porosity indicator. castsgna et. al; [2] (1993) gave representative polynomial relations for estimating ss from vp depending on data derived from sonic log. empirical equations by castanga for limestone and dolomite respectively are: vs = 0.05509 vp2 + 1.0168 vp – 1.0305 ... (3) vs = o.583 vp – 0.0776 ... (4) where vp and vs are in km/sec. he observed that vp/vs is sensitive to gas in most clastics and will often show a marked decrease in its presence. the response of carbonate rocks to gas is variable, a discrepancy which may be attributed to pore geometry. the gas effect may not be observed on well log if the depth of penetration does not exceed the invaded zone. eskandari et.al 2004, [3] proposed a method to predict vs from wireline data using multiple regression and neural network technique. at first they obtained equation for limestone and dolomite depending on castagna relationships: vs =-0.i236 vp2 + 1.6126 vp – 2.3057 ... (5) they complete their study to show the effect of petrophysical parameter on the predicted vs in carbonate rocks and concluded that vs decreases with increasing porosity and deep resistivity and increases with increasing bulk density. w.m al-kattan 2008, [4] depending on the fact that porosity measured by compressional wave velocity or by shear wave velocity, in carbonate rocks, should be equal for the same sample. she predicts vs from vp depending on wyille equation and used a statistical method to propose the given equation: vs =0.5734 vp -90.337 ... (6) where vp, vs in m/sec. results and discussion in order to predict a general equation for carbonate rocks, data taken from laboratory measurement and sonic log were used to draw the predicted empirical equations of pickett, castanga, eskandari, and wafa correlated as shown in fig (1). wafa m. al-kattan -available online at: www.iasj.net ijcpe vol.16 no.4 (dec. 2015) 47 fig 1, vp-vs predicted relations fig 2, the general relation between vp, vs for carbonate rocks. the data have been replotted, as shown in fig. (2), using a statistical method a general exponential relationship was established for carbonate rocks with r2= 0.995 the equation is given by: 𝑉𝑆 =0.699 𝑉𝑃 0.969 to examine the validity of this equation vp and vs data from a full, waveform sonic logs taken in different type of formations (limestone, limestone with some dolomite and shale, and dolomite with some sands) were correlated with the predicted vs as shown in fig (3). prediction of shear wave velocity for carbonate rocks 48 ijcpe vol.16 no.4 (dec. 2015) -available online at: www.iasj.net fig. 3, cross plot between measured vs and predicted vs the point's lies on a straight line represent the vs data from logs while the other points are the vs predicted from the proposed equation using vp data from the same logs. remembering that all the models assume clean water saturated formation the scattering can be easily explained. the data were taken from complex formations with a range of porosity vary from 3-25%, the shale content vary from 0-30%. this leads to the deviation of the predicted vs from the measured vs. because vs decreases with increasing porosity while vp is less sensitive to porosity, also vs decreases more than vp with increasing shale content. the deviated points are those with high porosity and shale content. the matrix shear wave velocities for limestone and dolomite measured at laboratory are equal to 3384 m/sec and 3872 m/sec respectively. using the predicted equation the velocities are 3409 m/sec and 3725 m/sec respectively which is very close to the measured values. for porosity ranging from 5-20%, the shear wave velocities measured in laboratory for limestone are 2896 m/sec – 2134 m/sec. the predicted velocities are 3409 m/sec – 3725 m/sec. in dolomite the laboratory measured velocities, for the same porosity ranging, are 3353 m/sec – 2286 m/sec while the predicted velocities are 3253 m/sec – 2462 m/sec. it can be noted that the measured and the predicted velocities are very close which confirm the validity of the predicted equation. wafa m. al-kattan -available online at: www.iasj.net ijcpe vol.16 no.4 (dec. 2015) 49 conclusion the proposed equation gives very accepted shear wave velocities predicted from compressional wave velocities in carbonate rock. in future work, the influence of porosity and shaliness on velocities should not be ignored, when the porosity and shaliness values are high, in the prediction of vs from vp, also the effect of density should be considered to get a more comprehensive relationship. nomenclature vp: compressional wave velocity, m/s vs: shear wave velocity, m/s δt: interval compressional transit time, μsec/f δts: interval shear transit time, μsec/f references 1pickett g.r. "acoustic character logs and their application in formation evaluation" j. pet. tech. june, 1963, 15 no.6. 2castagna j.p., and batzle m.l., and kan, t.k., 1993, "the link between rock properties and avo response" geophys. 124-157 3eskandari, h., rezaee m.r., and mohammadina, m., 2004, "application of multiple regression and artificial neural network techniques to predict shear wave velocity from wirleline log data for carbonate reservoir, south-west iran". 4wafa m. al-kattan, 2008, "a comprehensive approach to the interlock between the carbonate rock mechanical properties, and cementation factor", college of engineering, petroleum dept., university of baghdad. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.23 no.4 (december 2022) 43 – 48 eissn: 2618-0707, pissn: 1997-4884 corresponding author: name: basma i. waisi, email: basmawaisi@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. effect of solvent type on pan–based nonwoven nanofibers membranes characterizations haneen s. al-okaidy and basma i. waisi department of chemical engineering, college of engineering, university of baghdad abstract electrospun nanofiber membranes are employed in a variety of applications due to its unique features. the nanofibers' characterizations are effected by the polymer solution. the used solvent for dissolving the polymer powder is critical in preparing the precursor solution. in this paper, the polyacrylonitrile (pan)-based nanofibers were prepared in a concentration of 10 wt.% using various solvents (nmp, dmf, and dmso). the surface morphology, porosity, and the mechanical strength of the three prepared 10 wt.% pan-based nanofibers membranes (pan/nmp, pan/dmf, and pan/dmso) were characterized using the scanning electron microscopy (sem), dry-wet weights method, and dynamic mechanical analyzer (dma). using dmf as a solvent resulted in a long, beaded, homogeneous, and smooth surface fibrous structure with an average diameter of 260 nm, which was the best among the solvents tested in this study in terms of porosity and mechanical strength. keywords: nanofibers, electrospinning, solvent, mechanical strength. received on 22/06/2022, accepted on 04/08/2022, published on 30/12/2022 https://doi.org/10.31699/ijcpe.2022.4.6 1introduction according to reports, polymer fibers have several applications, especially in functional textiles and composite reinforcements [1]. melt, dry, and wet spinning, in which mechanical forces are employed to extrude polymer fluids, are traditional techniques for manufacturing polymeric fibers. according to vasanthan [2], these procedures permit the fabrication of fibers with a diameter of roughly 10 to 500nm. recently, the researchers disclosed the electrospinning technology, which offers good prospects for the production of submicron polymer nanofibers. electrospinning has grabbed the attention of both the scientific and corporate communities because it eliminates the limits of current fiber production processes [3]. electrospinning is a versatile method that utilises electrostatic forces to generate polymer nanofibers in a simple manner. the anode of a high voltage power source is briefly linked to a syringe holding polymer solution, while the cathode is connected to the fiber collector (rotating drum). during electrospinning, an electric field is generated between the capillary tip of the needle and the collector. when the applied voltage reaches a specific level, the surface tension of the polymer solution is overcome, and a single jet emits from a taylor cone. then, as a single jet passes from the capillary tip to the collector, whipping instability ensues. in the end, a single jet is split, the solvent evaporates, and nanofibers are collected on a collector [4, 5]. it is well known that the characterizations of electrospun fibrous membranes are affected by several factors, including solution properties, process parameters, and the environment [6]. the electrical conductivity, viscosity, and evaporation rate of the solvent are polymer solution properties that could determine the nanofiber's final characteristics. for the production of smooth and bead-free electrospun nanofibers, the selection of the polymer-dissolving solvent is crucial [7]. before selecting a solvent for the electrospinning process, two parameters are normally considered: the solubility of the polymer and the boiling point of the solvent. the boiling point of a solvent approximates its volatility. in general, volatile solvents are utilised due to their high evaporation rates, which allow for the straightforward evaporation of the solvent from the nanofibers as they travel from the needle tip to the collector. however, particularly volatile solvents are normally avoided because their high evaporation rates cause the jet at the needle tip to dry out and clog. similarly, less volatile solvents are avoided because their low evaporation rate prevents nanofiber jets from drying out during flight. the deposition of nanofibers containing a solvent on the collector will result in the creation of nanofiber beads [8, 9]. thus, the volatility of the solvent must fall within a particular range; a highly volatile solvent may result in ribbon/flat fibers or intermittent spinning due to polymer solidification at the spinneret tip. extremely low volatility, on the other hand, may result in the collection of wet, fused, or no fibers [5, 10]. polyacrylonitrile (pan) is one of the most prevalent polymers utilized in filtration membranes. it is soluble in numerous organic solvents, including n-methyl-2http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:basmawaisi@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2022.4.6 h. s. al-okaidy and b. i. waisi / iraqi journal of chemical and petroleum engineering 23,4 (2022) 43 48 44 pyrrolidone (nmp), n,n-dimethylformamide (dmf), and dimethyl sulfone (dmso) [11, 12]. due to their inexpensive cost of raw materials, ease of synthesis, and good heat resistance, polyacrylonitrile (pan)-based precursors are widely utilized in industrial and medical applications. the manufacturing of carbon fibers, medication delivery, wound dressing, sensor materials, and composite reinforcement are a few uses of panbased membranes [13, 14]. in this investigation, three types of pan-based precursor solutions were employed in the electrospinning technique to produce nanofiber membranes. pan polymer was dissolved in nmp, dmf, and dmso to form precursor solutions pan/nmp, pan/dmf, and pan/dmso. to examine the effect of the solvent type on the surface morphology, porosity, and mechanical strength of three types of nanofiber membranes, scanning electron microscopy (sem), the dry-wet weights technique, and the dynamic mechanical analyzer (dma) was used. 2materials and methods 2.1. electrospinning of nanofibers membranes polyacrylonitrile (pan) (molecular weight: 150,000 g/mol). aldrich and alfa aesar supplied the solvents nmethyl-2-pyrrolidone (nmp) (density: 1.03 g/cm³), n,ndimethylformamide (dmf) (density: 0.948 g/cm³), and dimethyl sulfoxide (dmso) (density: 1.1 g/cm³). in order to prepare the precursor solutions of 10 wt. % pan/nmp, 10 wt. % pan/dmf, and 10 wt. % pan/dmso, a specific amount of pan was dissolved for 5 hours at room temperature in nmp, dmf, and dmso, respectively. all of the nanofiber membranes in this study were produced by the showed electrospinning method in fig. 1. this system consists of a pulling motion of polymer droplets in a high-voltage electrostatic field. the electrospinning apparatus consists of four primary components: a syringe containing the precursor solution, a metallic needle with an inner diameter of 0.6 mm, a voltage power supply, and a collector drum [15, 16]. fig. 1. the digital image diagram of the used electrospinning system the electrospinning conditions were 1 ml/h of solution flow, 70 rpm of collector rotation, and 15 cm of needleto-collector distance. voltages of 19, 22, and 27 kv were applied to 10 % pan/nmp, 10 % pan/dmf, and 10 % pan/dmso, respectively. all nanofiber membranes were fabricated at 20 % relative humidity and 25 degrees celsius. 2.2. membrane characterizations 2.2.1. morphology of membrane surface the scanning electron microscopy (sem) method was utilized to characterize the surface characteristics of nanofiber membranes, such as the structure and diameter of the fibers. the average fiber diameters were calculated by analyzing the fiber sizes of thirty fibers of each membrane sample using image j software and the obtained images (national institutes of health, usa). 2.2.2. porosity the porosity of a membrane is a fundamental criterion for many membrane applications, particularly membrane separation performance. each membrane sample was weighed and then submerged in distilled water for one hour to determine its porosity. the sample's dry and wet weights were recorded before and after immersion in water, respectively. the nanofiber membranes' porosity was then calculated using equation 1: 𝑃𝑜𝑟𝑜𝑠𝑖𝑡𝑦 (%) = (𝑊1 − 𝑊2) 𝐴 ∗ 𝑡 ∗ 𝜌⁄ (1) where: w1 and w2 are wet and dry membrane mass (g), a is membrane area (cm2), t is membrane thickness (cm), and ρ: water density at room temperature g/cm3. 2.2.3. mechanical properties the mechanical property of the membrane is an important aspect of the membrane's practical applications like reusability, handling, and anti-deformation capacity [17]. mechanical properties of the membranes were evaluated using the breaking strength and young’s modulus of the membrane samples using a dynamic mechanical analyzer (dma) (ag-a10t, shimadzu, japan). the specimen size of 10 cm in length and 1 cm in width was used for the tests, all performed at 25 °c and ambient humidity. young's modulus quantifies the elasticity of a material; it is defined as the ratio of stress to strain [18, 19]. young's modulus of the flexible materials is low. 2.2.4. water contact angle water contact angle is a convenient way to assess the hydrophilic/hydrophobic properties of the membrane surfaces and the interaction energy between the surface and water drop. the contact angle of the membrane surface can be defined as the intersection angle between rounded collector power supply syringe pump h. s. al-okaidy and b. i. waisi / iraqi journal of chemical and petroleum engineering 23,4 (2022) 43 48 45 water droplet and the membrane interfaces. membranes of a water contact angle greater than or equal to 90° is counted as hydrophobic membranes, while the contact angle lower than 90o correspond to hydrophilic surfaces [12]. one of the easiest ways to measure the water contact angle is using a goniometer. this device contains a syringe of a liquid that is directed perpendicularly down onto the membrane surface, launching the droplet, and a digital camera of high accuracy. 3results and discussions it is well documented in the scientific literature [11] that solvent parameters, such as dielectric properties, surface tension, density, conductivity, and volatility, strongly affect the morphology of electrospun nanofibers. fig. 2 depicts the surface morphology of 10% pan-based nanofiber membranes treated with various solvents (nmp, dmf, dmso). the sem images in figs. 2a and c demonstrated that spinning with nmp and dmso solutions produced fibers that were nonwoven and stuck, respectively. with an average fiber diameter of 240 nm, the pan/nmp nanofibers comprised several beads joined by microscopic fibers along with some stuck fibers. in addition, the pan/dmso nanofibers were big, uneven, and had an average diameter of 600 nm. nevertheless, fig. 2b demonstrated that employing the dmf solvent as a solvent for pan resulted in the production of beadless, uniform, smooth, long fibers that were randomly distributed in a nonwoven structure and had an average diameter of 260 nm. due to its low boiling point (154 ºc), it was discovered that dmf evaporated swiftly, leaving the nanofibers dry. due to their high boiling points (189 and 202 ºc, respectively), dmso and nmp have low evaporation rates, resulting in moist nanofiber webs after electrospinning. thus, the late evaporation of the solvents (nmp and dmso) and the relaxing of the fibers during a lengthy drying period may account for the small and large diameters of the nanofibers formed from nmp and dmso, respectively [12]. (a) (b) (c) fig. 2. the sem images of 10 wt.% pan-based electrospun nanofibers membrane using different solvents (a) nmp, (b) dmf, (c) dmso fig. 3 showed that the porosities of the different prepared membranes increased with average diameters increase. the porosities of pan/nmp, pan/dmf, and pan/dmso were (82%, 95%, and 96%). these results of porosities contributed to the fiber diameters of the fabricated membranes, the porosity of nmp is low because of the beads and small fibers, while the porosity of dmso is large due to the large welded fibers. the porosity of dmf is high because of the nonwoven structure of the regular and continuous long fibers. fig. 4 indicated that using the dmf as a solvent produced fibers of higher strength due to their morphology; continuous polymeric fiber with no beadlike structure. the pan/nmp showed a low strength due to the existence of the beads with the fibers. although the large fibers of the pan/dmso membrane, the strength was low, contributing to the fibers' irregular formations [20]. the young’s modulus (stiffness) of pan/nmp membranes showed the highest value due to the low number of fibers and the beads existence, as shown in the sem image. in contrast, both pan/dmf and pan/dmso membranes contained continuous fibers, resulting in a low value of young’s modulus. the flexibility of the pan/dmso is lower than that of pan/dmf because of the larger fiber sizes and the sticky fibers' existence. fig. 3. the porosity and average fibers size of fabricated 10 wt. % pan-based electrospun nanofibers membrane at different solvents according to literature, the surface porosity is associated to the contact angle of a membrane by affecting the surface energy. the porosity has the opposite relationship with contact angle which means h. s. al-okaidy and b. i. waisi / iraqi journal of chemical and petroleum engineering 23,4 (2022) 43 48 46 polyacrylonitrile nanofibers with the highest porosity showed the lowest water contact angle value [21]. table 1 showed that the greater contact angle (110º) is for pan/nmp nanofiber membranes in comparison with pan/dmf nanofiber membranes (96º), and pan/dmso nanofiber membranes (73º). this result can be ascribed to the surface porosity in the case of nmp < dmf< dmso, as shown previously in fig. 3. the solvent type showed obvious effect on the membrane porosity and contact angle due to the fibers morphology and the solvent evaporation rate during the nanofibers fabrication. fig. 4. mechanical properties (breaking strength and young`s modulus) of 10% pan-based electrospun nanofibers membrane using different solvents table 1. the contact angel values of the various fabricated 10 % pan-based electrospun nanofibers membranes using different solvents (dmf, dmso, and nmp) the 10 % pan-based electrospun nanofibers membranes contact angle )o( pan/dmf 96 pan/dmso 73 pan/nmp 110 4conclusions this study has proven that solvent selection is one of the most important factors in defining the morphology of pan nanofiber membranes produced by electrospinning. the features of the solution were influenced by the characteristics of the solvent (nmp, dmf, and dmso); only dmf performed well in terms of electrospinnability. the nanofiber membranes electrospun from a dmf solvent-containing solution (10 % pan/dmf) had the most desirable fiber shape and mechanical qualities; long, continuous, and beadless nanofibers. also the solvent type showed an obcious effect on the water contact angle of the fabricated nanofibers. the nmp and dmso solvents produced irregular fibers. using the nmp as a solvent produced hydrophobic pan-based nanofibers with the highest water contact angle (110º), while the dmso produced the lowest water contact angle (73º). due to the regular structure, high porosity, hydrophobicity, and high mechanical strength of 10% pan/dmf nanofiber membranes, they could be useful for numerous prospective applications, such as biomedical, intelligent textiles, and nanofiltration. references [1] s. m. alkarbouly and b. i. waisi, “fabrication of electrospun nanofibers membrane for emulsified oil removal from oily wastewater,” baghdad sci. j., no. may, pp. 1238–1248, 2022. [2] n. vasanthan, polyamide fiber formation: structure, properties and characterization, vol. 1. woodhead publishing limited, 2009. [3] j. h. hong, e. h. jeong, h. s. lee, d. h. baik, s. w. seo, and j. h. youk, “electrospinning of polyurethane/organically modified montmorillonite nanocomposites,” j. polym. sci. part b polym. phys., vol. 43, no. 22, pp. 3171–3177, 2005. [4] b. i. waisi, “carbonized copolymers nonwoven nanofibers composite : surface morphology and fibers orientation,” iraqi j. chem. pet. eng., vol. 20, no. 2, pp. 11–15, 2019. [5] d. lukáš et al., “physical principles of electrospinning (electrospinning as a nano-scale technology of the twenty-first century),” text. prog., vol. 40, no. may, pp. 01–140, 2009. [6] r. erdem, i. usta, m. akalin, o. atak, m. yuksek, and a. pars, “the impact of solvent type and mixing ratios of solvents on the properties of polyurethane based electrospun nanofibers,” appl. surf. sci., vol. 334, pp. 227–230, 2015. [7] y. lee, b. s. kim, j. h. hong, s. park, h. kim, and i. s. kim, “enhanced mechanical properties and pretension effects of polyurethane (pu) nanofiber filaments prepared by electrospinning and dry twisting,” j. polym. res., vol. 19, no. 2, 2012. [8] j. nam, y. huang, s. agarwal, and j. lannutti, “improved cellular infiltration in electrospun fiber via engineered porosity,” tissue eng., vol. 13, no. 9, pp. 2249–2257, 2007. [9] t. j. sill and h. a. von recum, “electrospinning: applications in drufile delivery and tissue engineering” biomaterials, vol. 29, no. 13, pp. 1989– 2006, 2008. [10] a. haider, s. haider, and i. k. kang, “a comprehensive review summarizing the effect of electrospinning parameters and potential applications of nanofibers in biomedical and biotechnology,” arab. j. chem., vol. 11, no. 8, pp. 1165–1188, 2018. https://bsj.uobaghdad.edu.iq/index.php/bsj/article/view/6421 https://bsj.uobaghdad.edu.iq/index.php/bsj/article/view/6421 https://bsj.uobaghdad.edu.iq/index.php/bsj/article/view/6421 https://bsj.uobaghdad.edu.iq/index.php/bsj/article/view/6421 https://www.sciencedirect.com/science/article/pii/b9781845693800500072 https://www.sciencedirect.com/science/article/pii/b9781845693800500072 https://www.sciencedirect.com/science/article/pii/b9781845693800500072 https://onlinelibrary.wiley.com/doi/abs/10.1002/polb.20610 https://onlinelibrary.wiley.com/doi/abs/10.1002/polb.20610 https://onlinelibrary.wiley.com/doi/abs/10.1002/polb.20610 https://onlinelibrary.wiley.com/doi/abs/10.1002/polb.20610 https://onlinelibrary.wiley.com/doi/abs/10.1002/polb.20610 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/545 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/545 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/545 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/545 https://www.tandfonline.com/doi/abs/10.1080/00405160902904641 https://www.tandfonline.com/doi/abs/10.1080/00405160902904641 https://www.tandfonline.com/doi/abs/10.1080/00405160902904641 https://www.tandfonline.com/doi/abs/10.1080/00405160902904641 https://www.sciencedirect.com/science/article/abs/pii/s0169433214023666 https://www.sciencedirect.com/science/article/abs/pii/s0169433214023666 https://www.sciencedirect.com/science/article/abs/pii/s0169433214023666 https://www.sciencedirect.com/science/article/abs/pii/s0169433214023666 https://www.sciencedirect.com/science/article/abs/pii/s0169433214023666 https://link.springer.com/article/10.1007/s10965-011-9774-4 https://link.springer.com/article/10.1007/s10965-011-9774-4 https://link.springer.com/article/10.1007/s10965-011-9774-4 https://link.springer.com/article/10.1007/s10965-011-9774-4 https://link.springer.com/article/10.1007/s10965-011-9774-4 https://www.liebertpub.com/doi/abs/10.1089/ten.2006.0306 https://www.liebertpub.com/doi/abs/10.1089/ten.2006.0306 https://www.liebertpub.com/doi/abs/10.1089/ten.2006.0306 https://www.liebertpub.com/doi/abs/10.1089/ten.2006.0306 https://www.sciencedirect.com/science/article/abs/pii/s0142961208000203 https://www.sciencedirect.com/science/article/abs/pii/s0142961208000203 https://www.sciencedirect.com/science/article/abs/pii/s0142961208000203 https://www.sciencedirect.com/science/article/abs/pii/s0142961208000203 https://www.sciencedirect.com/science/article/pii/s1878535215003275 https://www.sciencedirect.com/science/article/pii/s1878535215003275 https://www.sciencedirect.com/science/article/pii/s1878535215003275 https://www.sciencedirect.com/science/article/pii/s1878535215003275 https://www.sciencedirect.com/science/article/pii/s1878535215003275 h. s. al-okaidy and b. i. waisi / iraqi journal of chemical and petroleum engineering 23,4 (2022) 43 48 47 [11] n. ucar, n. kizildag, a. onen, i. karacan, and o. eren, “polyacrylonitrile-polyaniline composite nanofiber webs : effects of solvents , redoping process and dispersion technique,” fibers polym., vol. 16, no. 10, pp. 2223–2236, 2015. [12] a. hamta, f. z. ashtiani, m. karimi, and a. safikhani, “manipulating of polyacrylonitrile membrane porosity via sio2 and tio2 nanoparticles : thermodynamic and experimental point of view,” polym. adv. technol., no. october, pp. 1–14, 2020. [13] b. i. waisi, s. s. manickam, n. e. benes, a. nijmeijer, and j. r. mccutcheon, “activated carbon nanofiber nonwovens: improving strength and surface area by tuning the fabrication procedure,” ind. eng. chem. res., vol. 58, pp. 4084–4089, 2019. [14] o. a. a. mahmood and b. i. waisi, “synthesis and characterization of polyacrylonitrile based precursor beads for the removal of the dye malachite green from its aqueous solutions,” desalin. water treat., vol. 216, pp. 445–455, 2021. [15] m. al-furaiji, m. kadhom, k. kalash, b. waisi, and n. albayati, “preparation of thin-film composite membranes supported with electrospun nanofibers for desalination by forward osmosis,” drink. water eng. sci., vol. 13, pp. 51–57, 2020. [16] b. i. waisi, j. t. arena, n. e. benes, a. nijmeijer, and j. r. mccutcheon, “activated carbon nanofiber nonwoven for removal of emulsified oil from water,” microporous mesoporous mater., vol. 296, p. 109966, 2020. [17] n. naseeb, a. a. mohammed, t. laoui, and z. khan, “a novel pan-go-sio2 hybrid membrane for separating oil and water from emulsified mixture,” materials (basel)., vol. 12, no. 212, pp. 1– 13, 2019. [18] m. rabiei et al., “measurement modulus of elasticity related to the atomic density of planes in unit cell of crystal lattices,” materials (basel)., vol. 13, p. 4380, 2020. [19] a. greiner and j. h. wendorff, “electrospinning : a fascinating method for the preparation of ultrathin fibers angewandte,” angew. chem. int. ed., vol. 46, pp. 5670–5703, 2007. [20] c. zhang, p. li, and b. cao, “electrospun microfibrous membranes based on pim-1/poss with high oil wettability for separation of oil– water mixtures and cleanup of oil soluble contaminants,” ind. eng. chem. res., vol. 54, pp. 8772–8781, 2015. [21] m. b. ghandashtani, f. z. ashtiani, m. karimi, and a. fouladitajar, “a novel approach to fabricate high performance nano-sio2 embedded pes membranes for microfiltration of oil-in-water emulsion,” appl. surf. sci., vol. 349, pp. 393–402, 2015. https://link.springer.com/article/10.1007/s12221-015-5426-3 https://link.springer.com/article/10.1007/s12221-015-5426-3 https://link.springer.com/article/10.1007/s12221-015-5426-3 https://link.springer.com/article/10.1007/s12221-015-5426-3 https://link.springer.com/article/10.1007/s12221-015-5426-3 https://onlinelibrary.wiley.com/doi/abs/10.1002/pat.5138 https://onlinelibrary.wiley.com/doi/abs/10.1002/pat.5138 https://onlinelibrary.wiley.com/doi/abs/10.1002/pat.5138 https://onlinelibrary.wiley.com/doi/abs/10.1002/pat.5138 https://onlinelibrary.wiley.com/doi/abs/10.1002/pat.5138 https://onlinelibrary.wiley.com/doi/abs/10.1002/pat.5138 https://pubs.acs.org/doi/abs/10.1021/acs.iecr.8b05612 https://pubs.acs.org/doi/abs/10.1021/acs.iecr.8b05612 https://pubs.acs.org/doi/abs/10.1021/acs.iecr.8b05612 https://pubs.acs.org/doi/abs/10.1021/acs.iecr.8b05612 https://pubs.acs.org/doi/abs/10.1021/acs.iecr.8b05612 https://www.deswater.com/dwt_articles/vol_216_papers/216_2021_445.pdf https://www.deswater.com/dwt_articles/vol_216_papers/216_2021_445.pdf https://www.deswater.com/dwt_articles/vol_216_papers/216_2021_445.pdf https://www.deswater.com/dwt_articles/vol_216_papers/216_2021_445.pdf https://www.deswater.com/dwt_articles/vol_216_papers/216_2021_445.pdf https://dwes.copernicus.org/articles/13/51/2020/ https://dwes.copernicus.org/articles/13/51/2020/ https://dwes.copernicus.org/articles/13/51/2020/ https://dwes.copernicus.org/articles/13/51/2020/ https://dwes.copernicus.org/articles/13/51/2020/ https://www.sciencedirect.com/science/article/abs/pii/s138718111930825x https://www.sciencedirect.com/science/article/abs/pii/s138718111930825x https://www.sciencedirect.com/science/article/abs/pii/s138718111930825x https://www.sciencedirect.com/science/article/abs/pii/s138718111930825x https://www.sciencedirect.com/science/article/abs/pii/s138718111930825x https://www.mdpi.com/1996-1944/12/2/212 https://www.mdpi.com/1996-1944/12/2/212 https://www.mdpi.com/1996-1944/12/2/212 https://www.mdpi.com/1996-1944/12/2/212 https://www.mdpi.com/1996-1944/12/2/212 https://www.mdpi.com/1996-1944/13/19/4380 https://www.mdpi.com/1996-1944/13/19/4380 https://www.mdpi.com/1996-1944/13/19/4380 https://www.mdpi.com/1996-1944/13/19/4380 https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.200604646 https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.200604646 https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.200604646 https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.200604646 https://pubs.acs.org/doi/abs/10.1021/acs.iecr.5b02321 https://pubs.acs.org/doi/abs/10.1021/acs.iecr.5b02321 https://pubs.acs.org/doi/abs/10.1021/acs.iecr.5b02321 https://pubs.acs.org/doi/abs/10.1021/acs.iecr.5b02321 https://pubs.acs.org/doi/abs/10.1021/acs.iecr.5b02321 https://pubs.acs.org/doi/abs/10.1021/acs.iecr.5b02321 https://www.sciencedirect.com/science/article/abs/pii/s0169433215011356 https://www.sciencedirect.com/science/article/abs/pii/s0169433215011356 https://www.sciencedirect.com/science/article/abs/pii/s0169433215011356 https://www.sciencedirect.com/science/article/abs/pii/s0169433215011356 https://www.sciencedirect.com/science/article/abs/pii/s0169433215011356 h. s. al-okaidy and b. i. waisi / iraqi journal of chemical and petroleum engineering 23,4 (2022) 43 48 48 ن تأثير نوع المذيب على توصيف أغشية األلياف النانوية غير المنسوجة المصنعة م بوليمر البولي اكريلونايتريل حنين صبيح الكعيدي و بسمة اسماعيل ويسي امعة بغدادج–كلية الهندسة -قسم الهندسة الكيمياوية الخالصة نطاق واسع في العديد من التطبيقات بسبب تستخدم أغشية األلياف النانوية المغزولة كهربائيا على حد خصائصها الفريدة، مثل المسامية العالية ومساحة السطح العالية لكل وحدة حجم. يعد محلول البوليمر أ الغ أمر ب العوامل الحاسمة التي تؤثر على توصيفات األلياف النانوية. المذيب المستخدم إلذابة مسحوق البوليمر لعاليةحلول البوليمر. ال يوجد معيار واضح للحكم على ما إذا كان المذيب ذي القابلية ااألهمية في تحضير م ير للذوبان للبوليمر سيكون جيدا للغزل الكهربائي مع خصائص قوة ميكانيكية جيدة. في هذا البحث، تم تحض nmp مذيبات مختلفةباستخدام wt.٪10 بتركيز pan األلياف النانوية باستخدام بوليمر االكريلونايتريل ثة. تم وصف مورفولوجيا السطح والمسامية والقوة الميكانيكية ألغشية األلياف النانوية الثالdmsoو dmfو باستخدام المجهر اإللكتروني pan/dmso ، وpan/nmp ،pan/dmf٪ من الوزن 10المحضرة بنسبة ائج أن . أظهرت النت (dma) الميكانيكي الديناميكي، وطريقة األوزان الجافة الرطبة، والمحلل (sem) الماسح 260كمذيب أنتج الياف طويلة، خالي من الخرزات، موحدة، وسطح أملس بمتوسط قطر dmf استخدام .نانومتر، وهو األفضل بين المذيبات المستخدمة في هذا العمل مع مسامية مناسبة وقوة ميكانيكية .ة، الغزل الكهربائي، المذيبات، القوة الميكانيكيةة: األلياف النانويلادالكلمات ال available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.23 no.3 (september 2022) 1 – 9 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: farah adil yaseen , email: phdfarah88@yahoo.com , name: ahmed faiq al-alawy, email: ahmedalalawy@yahoo.com, : name: adel sharif , email: a.sharif@surrey.ac.uk ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. mathematical modeling of a hollow fiber module used in pressure-retarded osmosis process farah adil yaseen a , ahmed faiq al-alawy b , adel sharif c a iraq national oil company, midland oil company, baghdad, iraq b department of chemical engineering, college of engineering, university of baghdad, baghdad, iraq c department of chemical and process engineering, university of surrey, surrey, uk abstract pressure retarded osmosis (pro) can be considered as one of the methods for utilizing osmotic power, which is a membrane-based technology. mathematical modeling plays an essential part in the development and optimization of pro energy-generating systems. in this research, a mathematical model was developed for the hollow fiber module to predict the power density and the permeate water flux theoretically. sodium chloride solution was employed as the feed and draw solution. different operating parameters, draw solution concentration (1 and 2 m), the flow rate of draw solution (2, 3, and 4 l/min), and applied hydraulic pressure difference (0 90 bar) was used to evaluate the performance of pro process of a hollow fiber module. the effect of these operational parameters was investigated on the theoretical permeate water flux and power density. according to the theoretical results, the permeate water flux and the power density increased with increasing the concentration of draw solution and the flow rate of the draw solution. while decreased with increasing the feed solution concentration. by increasing the applied hydraulic pressure on the draw solution, the water flux decreased and the produced power density increased. the maximum power density and the corresponding permeate water flux of 2 m nacl draw solution was approximately 16.414 w/m 2 and 11.818 lmh respectively, which occurs at an applied hydraulic pressure of 50 bar. keywords: mathematical model, osmotic power, hollow fiber membrane, pressure retarded osmosis. received on 17/05/2022, accepted on 04/06/2022, published on 30/09/2022 https://doi.org/10.31699/ijcpe.2022.3.1 1introduction pressure retarded osmosis (pro) can be considered as one of the methods for utilizing osmotic power, which is a membrane-based technology [1]. it is considered as one of the renewable energies, which was investigated over the last decade intensively [2] due to its superior energy efficiency and high power density, as well as its compatibility with highly salty solutions [3]. the energyreleasing process through the mixing of salt-water and fresh-water can be demonstrated by considering basic osmotic principles [4]. the process of pro can be considered as one of the most widely investigated technologies for harnessing salinity gradients and converting the osmotic power into useful work [5]. the pressure retarded osmosis process utilizes the osmotic pressure difference that develops when a semipermeable membrane separates two different concentration solutions for driving the water permeation from the lowconcentration solution “feed solution fs” into the highconcentration solution “draw solution ds”. a hydraulic pressure less than the osmotic pressure difference is applied to the draw solution, thereby “retarding” the flux of water across the semipermeable membrane. a hydroturbine extracts useful work from the expanding volume of the draw solution [6]. it is considered as an intermediate between reverse osmosis (ro) and forward osmosis (fo) processes. the same as to ro, the hydraulic pressure is applied to the side of the draw solution against the osmotic pressure gradient but it is smaller than the osmotic pressure difference. consequently the net flux of water remains towards the concentrated draw solution, which is in a direction identical to that of the fo process [7]. fig. 1 represents the flux directions and driving force for the pro process that is occurring because of the contact of pure water and saline water through a semipermeable membrane [8]. fig. 1. representation of solvent flow in pressure retarded osmosis (pro) [8] http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:phdfarah88@yahoo.com mailto:ahmedalalawy@yahoo.com mailto:a.sharif@surrey.ac.uk http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2022.3.1 f. a. yaseen et. al / iraqi journal of chemical and petroleum engineering 23,3 (2022) 1 9 2 in 2009, statkraft, which is a norwegian company in the clean energy sector, has constructed the first prototype plant of osmotic power in the world by mixing seawater and fresh river water across a semi-permeable membrane. it is planning to commercialize osmotic power with a projected energy cost-competitive against other renewable energy sources. based on statkraft, the power density of the membrane was determined to be between 4 6 w/m 2 to make pro profitable [9]. another prototype hybrid ropro was constructed by the mega-ton water system project in japan in 2010. this plant aimed to hybridize seawater reverse osmosis (swro) and wastewater reclamation systems for power generation. the maximal power density of this system was 13.3 w/m 2 at about 27 bar hydraulic pressure difference [10], [11]. yasukawa et al., 2018 [12] had examined the efficiency of pressure-retarded osmosis process using cta hollow-fiber membrane, the maximum power density was 0.14 w/m 2 at about 4 bar hydraulic pressure difference when using 0.5 m nacl as draw solution ds and tap water as feed solution. the research aims to develop a mathematical model of the water flux and power density for a pro hollow fiber membrane and examine the effect of many parameters on the performance of the pressure retarded osmosis process theoretically. 2modeling the mathematical model describes the mass transport in detail in four transport-zones, which are boundary layers on the two surfaces of the membrane, within the porous-support layer, and across the active layer of the membrane. the precise mass transport description is highly significant for the evaluation of the performance of the hf membrane. therefore, the mathematical model was developed by using the minimum of assumptions, so it takes into consideration all negative effects that reduce the performance of the pro process. 2.1. mass transport in the realistic hollow fiber membrane fig. 2 illustrates a cross-section of a hollow fiber membrane with an active layer at the outer hf surface. the draw solution is in direct contact with the active layer outside the hollow fiber, whereas the feed solution is inside the hollow fiber. in this type of configuration, water radially permeates, through porous-support and active layers, toward the ds outside hollow fiber (shell-side). on the contrary, the solute diffuses down the concentration gradient from ds outside to feed solution within hollow fiber (lumen-side). fig. 2. schematic showing the cross-section of hf membrane and its geometrical parameters with a realistic membrane and hydrodynamics, four phenomena are occurring that reduce the trans-membrane water flux and power generation in the pro process as presented in fig. 3: 1. the concentrative external concentration polarization (ecpconcentrative ) on the feed solution side raises cf,b (bulk feed solution concentration) to cf,m (solute concentration on the support layer of membrane surface that faces feed solution). 2. the dilutive external concentration polarization (ecpdilutive ) on the draw side reduces cd,b (bulk draw solution concentration) to cd,m (solute concentration on the active layer of the membrane surface that faces draw solution). 3. the internal concentration polarization (icp) within the porous support layer elevates the solute concentration from cf,m to cf,i (solute-concentration at the interface between the active layer and the support layer). 4. the reverse salt ions diffuse from the draw solution to the feed solution because of the concentration gradient across the membrane. fig. 3. concentration profile over an hf membrane f. a. yaseen et. al / iraqi journal of chemical and petroleum engineering 23,3 (2022) 1 9 3 as illustrated in fig. 3, the effects of both ecp and icp combine to reduce the osmotic pressure difference across the membrane to some effective value ∆πeff. that is much smaller than ∆π. a. mass transport in support and boundary layers the salt mass transport in the porous-support layer of membrane and the boundary layer for each membrane side will equal the summation of diffusive and convective salt transport. the diffusive salt transport is defined by fick's law, whereas the convective transport of salt represents the product of the local solute concentration c(r) and the water flux jw(r). hence, the salt mass transfer can be expressed by the general equation at the radial position (r) [13]: js(r) = d ′ dc(r) dr − jw(r). c(r) (1) where: jw(r) represents the water flux, js(r) represents the salt flux, c(r) represents the concentration of the salt at the radial position r, and d′ represents the solute general diffusion coefficient. the fluxes jw(r) and js (r) in eq. (1) are the areal fluxes that represent volume flow rate across a unit area of the membrane. the fluxes are not constant with respect to r due to the available area of flow changes in the radial direction. however, the linear fluxes that represent the volume flow rate through a unit length of the hollow fiber membrane, are constant and independent of the radialposition. thus, eq. (1) can be re-written by converting the areal water flux jw(r) and areal solute flux js(r) to linear water flux ξw and linear solute flux ξs, respectively, ξw = 2πrjw(r) and ξs = 2πrjs(r): ξs = 2πrd ′ dc(r) dr − ξw. c(r) (2) dividing eq. (2) by ξw gives: ξs ξw = 2πrd′ ξw dc(r) dr − c(r) (3) eq. (3) can be solved as an ordinary differential equation by applying the separation of variables method. rearrangement of eq. (3) to separate the variables: dr r = 2πd′ ξw dc(r) c(r)+ ξs ξw (4)  porous support layer in the porous-support layer of the membrane, the differential equation (eq. 4) can be used, but, the general diffusion coefficient (d′) simply represents the effective solute diffusion coefficient in the porous-support layer (ds): dr r = 2πds ξw dc(r) c(r)+ ξs ξw (5) the solute diffusion coefficient in the porous-support layer ds is given by [14]: ds = df.ε τ (6) where: df is the solute diffusion coefficient in the bulk feed solution, ε , and τ are the porosity and the tortuosity of the support layer structure of the membrane. therefore, eq. (5) can be rewritten as: dr r = 2π df.ε τ ξw dc(r) c(r)+ ξs ξw (7) the thickness of the active layer is very small in comparison with the thickness of the porous support layer and the boundary layers. therefore, no differentiation is done between the positions on both sides of the active layer when formulating the boundary conditions (i.e., ro + = ro − = ro) (fig. 3) [15]. c(r = ri) = cf,m b.c.1 c(r = ro − = ro) = cf,i b.c.2 integration over the porous membrane structure with the b.c. 1 and 2 yields: ∫ dr r ri ro = 2π df.ε τ ξw ∫ dc(r) c(r)+ ξs ξw cf,m cf,i (8) giving the solution: ln ( ri ro ) = 2π df.ε τ ξw ln ( cf,m+ ξs ξw cf,i+ ξs ξw ) (9) which can also be rewritten as eq. (10): cf,i = (cf,m + ξs ξw ) ( ro ri ) ξw.τ 2π df.ε − ξs ξw (10)  draw solution boundary layer on the draw solution side, solutes are diluted at the surface as water enters from the feed side, giving rise to dilutive ecp. as a result, the effective osmotic pressure difference would reduce from πd,b to πd,m. the reverse draw solute flux on the side of the draw solution can also be derived using the same differential equation as in eq. (4), with different boundary conditions. thus, the boundary conditions for ecp on the draw solution side are: f. a. yaseen et. al / iraqi journal of chemical and petroleum engineering 23,3 (2022) 1 9 4 c(r = ro + = ro) = cd,m b.c.3 c(r = ro + δd) = cd,b b.c.4 where: δd represents the thickness of the ds boundary layer. eq. (4) can be integrated over the draw solution boundary layer with b.c. 3 and 4. here, the general diffusion coefficient (d′) represents the solute diffusion coefficient in the bulk draw solution (dd). ∫ dr r ro+δd ro = 2π dd ξw ∫ dc(r) c(r)+ ξs ξw cd,b cd,m (11) giving the solution: ln ( ro+δd ro ) = 2π dd ξw ln ( cd,b+ ξs ξw cd,m+ ξs ξw ) (12) which: can also be rewritten as eq. (13): cd,m = (cd,b + ξs ξw ) ( ro ro+δd ) ξw 2πdd − ξs ξw (13)  film thickness on the draw solution side the film thickness on the draw solution side of the membrane δd (shell side) is given by [16]: where kd represents the mass transfer coefficient for the draw solution, can be defined by [17]: δd = dd kd (14) kd = shs.dd dh (15) where: shs is the sherwood number at the shell side, and dh is the hydraulic diameter at the shell side of the membrane. the sherwood number is determined from the following correlations [18]: shs = 1.25 scs 1 3⁄ (res dh l ) 0.93 (re = 0 − 500) (16) where: l is the module length, scs and res are the schmidt and reynolds numbers at the shell side, respectively. the reynold and schmidt numbers are determined as: res = ρd.ud.dh μd (17) scs = μd ρd.dd (18) where: ρd and μd are the density and dynamic viscosity of the draw solution, respectively, and ud is the velocity of the draw solution in the shell side and can be calculated as: ud = qd as (19) where: qd represents the volumetric flow rate of draw solution in the shell side, and as is the cross-sectional area of the shell side and can be calculated as: as = π 4 (di,module 2 − nfiberdo 2 ) (20) where: nfiber is the number of fibers in the module, di,module represents the inner diameter of the module, do is the outer diameter of the fiber. the hydraulic diameter of the shell side can be determined as [19]:  feed solution boundary layer a similar derivation can be conducted at the feed solution side with b.c. 5 and 6. here, the general diffusion coefficient (d′) represents the solute diffusion coefficient in the bulk feed solution (df). c(r = ri − δf) = cf,b b.c.5 c(r = ri) = cf,m b.c.6 where: δf represents the thickness of the fs boundary layer. ∫ dr r ri – δf ri = 2π df ξw ∫ dc(r) c(r)+ ξs ξw cf,b cf,m (22) giving the solution: cf,m = (cf,b + ξs ξw ) ( ri ri− δf ) ξw 2πdf − ξs ξw (23) substituting eq. (23) for cf,m in eq. (10) gives an expression for the concentration at the active layersupport layer interface, cf,i, that only depends on the bulk concentration. cf,i = ((cf,b + ξs ξw ) ( ri ri− δf ) ξw 2πdf ) ( ro ri ) ξw.τ 2π df.ε − ξs ξw (24)  film thickness on the feed solution side the film thickness on the feed solution side of the membrane δf (lumen-side) is given by [16]: δf = df kf (25) where kf represents the mass transfer coefficient for the feed solution, and can be defined by [20]: kf = shl.df di (26) f. a. yaseen et. al / iraqi journal of chemical and petroleum engineering 23,3 (2022) 1 9 5 di represents the inner diameter of the hf membrane, and shl is the sherwood number at the lumen side, which is determined from the following correlations [21]: shl = 1.62 scl 1 3⁄ . rel 1 3⁄ ( di l ) 1 3⁄ = 1.62 gzl 1 3⁄ , gzl ≥ 6 (27) or shl = 0.5 scl. rel ( di l ) = 0.5 gzl , gzl < 6 (28) where: l is the module length, scl and rel are the schmidt and reynolds numbers at the lumen side, respectively. gzl is the graetz number at the lumen side, defined as rel . scl. di/l. the reynold and schmidt numbers are calculated as follows: rel = ρf.uf.di μf (29) scl = μf ρf.df (30) where: uf is the velocity of the feed solution in the lumen side, di is the inner diameter of the fiber, ρf, and μf are the density and dynamic viscosity of the feed solution, respectively. uf = qf al (31) where: qf represents the volumetric flow rate of feed solution in the lumen side, and al is the cross-sectional area of the lumen side and can be calculated as follows: al = nfiber π 4 di 2 (32) b. mass transport across active layer the mass transport equations related to the water flux and solute flux through the active layer membrane at position ro are described by [15]: jw(ro) = ξw 2πro = a(δπactive − δp) (33) the effective osmotic pressure, δπactive, that governs the mechanism is [22], [23]: δπactive = (πd,m − πf,i) (34) therefore, eq. (33) can be written as: jw(ro) = ξw 2πro = a(πd,m − πf,i − δp) (35) and the salt flux through the active layer is written as: js(ro) = ξs 2πro = b(cd,m − cf,i) (36) where: b represents the salt permeability coefficient. the osmotic pressure (π) of any solution can be defined using van't hoff's equation [24], [25]: π = ncrgt (37) where: n is the number of ions in the dissociated salt, c is the solute molar concentration, rg represents the gas constant, and t represents the temperature of the solution. thus, we consider that: πd,m = nrgtcd,m (38) πf,i = nrgtcf,i (39) πf,m = nrgtcf,m (40) therefore, eq. (35) for the water flux can be rewritten as: dividing eq. (36) by eq. (41) yields the specific salt flux in pro, as follows: jw(ro) = ξw 2πro = anrgt(cd,m − cf,i) − aδp (41) ξs ξw = b anrgt (1 + aδp ξw 2πro⁄ ) (42) substituting cd,m in eq. (41) with its expression presented in eq. (13) and substituting ξs/ξw with its expression developed in eq. (42) yields eq. (43): πd,m = (πd,b + b a (1 + aδp ξw 2πro⁄ )) ( ro ro+δd ) ξw 2πdd − b a (1 + aδp ξw 2πro⁄ ) (43) substituting cf,i in eq. (41) with its expression presented in eq. (24) and substituting ξs/ξw with its expression developed in eq. (42) yields eq. (44): πf,i = (πf,b + b a (1 + aδp ξw 2πro⁄ )) ( ri ri− δf ) ξw 2πdf ( ro ri ) ξw.τ 2π df.ε − b a (1 + aδp ξw 2πro⁄ ) (44) substituting πd,m and πf,i in eq. (35) with its expression presented in eq. (43) and eq. (44) respectively, yields eq. (45): ξw = 2πroa [(πd,b + b a (1 + aδp ξw 2πro⁄ )) ( ro ro+δd ) ξw 2πdd − (πf,b + b a (1 + aδp ξw 2πro⁄ )) ( ri ri− δf ) ξw 2πdf ( ro ri ) ξw.τ 2π df.ε − δp] (45) replacing the linear flux, ξw, in eq. (45) with the areal flux, jw, by noting that ξw = 2πro jw : f. a. yaseen et. al / iraqi journal of chemical and petroleum engineering 23,3 (2022) 1 9 6 jw = a [(πd,b + b a (1 + aδp jw )) ( ro ro+δd ) rojw dd − (πf,b + b a (1 + aδp jw )) ( ri ri− δf ) rojw df ( ro ri ) rojw.τ df.ε − δp] (46) the terms in equations 46 and 47 are membrane parameters, solution properties, and measurable system conditions. the mathematical model for the pro process was solved iteratively by the aid of the microsoft excel program 2010 for a range of operating conditions to determine the permeate water flux. the water flux equation, eq. 46 was solved using goal seek function by providing an initial guess and then updating iteratively. according to the study, the hollow fibre pro membrane has water permeability coefficient equal to 0.471 l/m2 h.bar, salt permeability coefficient equal to 0.384 l/m2 h, and structural parameter equal to 855μm. fig. 4. modeled water flux vs. applied pressure difference for different ds concentrations (fs = 0.25 g/l nacl, t = 35 ºc, qd = 2 l/min, qf = 1 l/min) fig. 5. modeled power density vs. applied pressure difference for different ds concentrations (fs = 0.25 g/l nacl, t = 35 ºc, qd = 2 l/min, qf = 0.1 l/min) fig. 6 and fig. 7 demonstrate the impacts of applied pressure difference on the water flux and power density of the pro system under various feed solution concentrations. the other conditions such as temperature (35 ℃), ds flow rate (2 l/min), fs flow rate (1 l/min) were kept constant. as expected, the water flux and power density values decrease as the feed solution concentration becomes higher. increasing the feed solution concentration from 0.25 g/l (tap water) to 10 g/l (high-salinity brackish water) led to a decrease in both water flux (fig. 6) and power density (fig. 7). increasing the concentration of the feed solution induces a reduction in the effective osmotic pressure difference; hence, the driving force of the pro process decreases. when the feed solution concentration was increased from 0.25 g/l to 10 g/l, the power density decreased about 85% as shown in figure 7. fig. 6. modeled water flux vs. applied pressure difference for different fs concentrations (ds = 2m nacl, t = 35 ºc, qd = 2 l/min, qf = 1 l/min) fig. 7. modeled power density vs. applied pressure difference for different fs concentrations (ds = 2m nacl, t = 35 ºc, qd = 2 l/min, qf = 1 l/min) fig. 8 and fig. 9 represent the impact of the ds flow rate on the pro performance. they show how the water flux and and power density varies with hydraulic difference for various flow rates of draw solution (2, 3 and 4 l/min). as the ds flow rate increased, there was a little increase in the water flux and power density, such an increase was because of the decrease in the ds dilution effect. also, the flow changes the mass transfer boundary layer thickness at the membrane surface. it was observed that the power density increased around only 8 % when the flow rate of the draw solution was increased from 2 l/min to 4 l/min at 50 bar applied pressure difference. f. a. yaseen et. al / iraqi journal of chemical and petroleum engineering 23,3 (2022) 1 9 7 fig. 8. modeled water flux vs. applied pressure difference for different flow rates of draw solution (fs = 0.25 g/l, ds = 2m nacl, t = 35 ºc, qf = 0.1 l/min) fig. 9. modeled power density vs. applied pressure difference for different flow rates of draw solution (fs = 0.25 g/l, ds = 2m nacl, t = 35 ºc, qf = 0.1 l/min) 4conclusion in this study, a mathematical model was developed for the hf module to predict 𝐽𝑤 and 𝑊 theoretically by using the minimum of assumptions, so it takes into consideration all negative effects that reduce the performance of the pro process. maximum power density (15.248 w/m 2 ) occurred at an applied pressure difference of 50 bar for 2m draw solution concentration (102.8 bar osmotic pressure). therefore, this means that the maximum power density has occurred at an applied pressure difference of around 50% of the osmotic pressure difference(δp ≈ ∆π/2). increasing the concentration of the draw solution enhances the performance of the pro process in terms of water flux and power density by increasing the osmotic driving force, whereas increasing the concentration of the feed solution reduces the water flux and power density. when the draw solution flow rate increases from 2 to 4 l/min, a slight enhancement of power density and water flux was identified. references [1] d. i. kim, j. kim, and s. hong, “changing membrane orientation in pressure retarded osmosis for sustainable power generation with low fouling,” desalination, vol. 389, 2016. [2] k. touati and m. s. rahaman, “viability of pressureretarded osmosis for harvesting energy from salinity gradients,” renewable and sustainable energy reviews, vol. 131, no. february, p. 109999, 2020. [3] z. wang, d. hou, and s. lin, “gross vs . net energy : towards a rational framework for assessing the practical viability of pressure retarded osmosis,” journal of membrane science, vol. 503, pp. 132–147, 2016. [4] f. helfer, o. sahin, c. lemckert, and y. g. anissimov, “salinity gradient energy : a new source of renewable energy for,” no. february, pp. 3–13, 2013. [5] a. janson, d. dardor, m. al maas, j. minier-matar, a. abdel-wahab, and s. adham, “pressure-retarded osmosis for enhanced oil recovery,” desalination, vol. 491, no. march, p. 114568, 2020. [6] n. y. yip and m. elimelech, “performance limiting effects in power generation from salinity gradients by pressure retarded osmosis,” environmental science and technology, vol. 45, no. 23, pp. 10273–10282, 2011. [7] w. y. chia et al., “factors affecting the performance of membrane osmotic processes for bioenergy development,” energies, vol. 13, no. 2, 2020. [8] f. helfer, c. lemckert, and y. g. anissimov, “osmotic power with pressure retarded osmosis: theory, performance and trends a review,” journal of membrane science, vol. 453, pp. 337–358, 2014. [9] k. gerstandt, k. v. peinemann, s. e. skilhagen, t. thorsen, and t. holt, “membrane processes in energy supply for an osmotic power plant,” desalination, vol. 224, no. 1–3, pp. 64–70, 2008. [10] m. kurihara and h. takeuchi, “swro-pro system in ‘mega-ton water system’ for energy reduction and low environmental impact,” water (switzerland), vol. 10, no. 1, pp. 1–15, 2018. [11] w. a. n. chunfeng, “membrane technology for osmotic power,” 2016. [12] m. yasukawa, d. shigefuji, m. shibuya, y. ikebe, r. horie, and m. higa, “effect of ds concentration on the pro performance using a 5-inch scale cellulose triacetate-based hollow fiber membrane module,” membranes, vol. 8, no. 2, 2018. [13] e. sivertsen, t. holt, w. thelin, and g. brekke, “modelling mass transport in hollow fibre membranes used for pressure retarded osmosis,” journal of membrane science, vol. 417–418, pp. 69–79, 2012. [14] w. a. phillip, j. s. yong, and m. elimelech, “reverse draw solute permeation in forward osmosis: modeling and experiments,” environmental science and technology, vol. 44, no. 13, pp. 5170–5176, 2010. [15] z. l. cheng and t. s. chung, “mass transport of various membrane configurations in pressure retarded osmosis (pro),” journal of membrane science, vol. 537, no. may, pp. 160–176, 2017. https://www.sciencedirect.com/science/article/abs/pii/s0011916416300108 https://www.sciencedirect.com/science/article/abs/pii/s0011916416300108 https://www.sciencedirect.com/science/article/abs/pii/s0011916416300108 https://www.sciencedirect.com/science/article/abs/pii/s0011916416300108 https://www.sciencedirect.com/science/article/pii/s1364032120302902 https://www.sciencedirect.com/science/article/pii/s1364032120302902 https://www.sciencedirect.com/science/article/pii/s1364032120302902 https://www.sciencedirect.com/science/article/pii/s1364032120302902 https://www.sciencedirect.com/science/article/pii/s0376738815303355 https://www.sciencedirect.com/science/article/pii/s0376738815303355 https://www.sciencedirect.com/science/article/pii/s0376738815303355 https://www.sciencedirect.com/science/article/pii/s0376738815303355 https://www.sciencedirect.com/science/article/pii/s0376738815303355 https://www.ewra.net/wuj/pdf/wuj_2013_05_01.pdf https://www.ewra.net/wuj/pdf/wuj_2013_05_01.pdf https://www.ewra.net/wuj/pdf/wuj_2013_05_01.pdf https://www.ewra.net/wuj/pdf/wuj_2013_05_01.pdf https://www.sciencedirect.com/science/article/pii/s0011916420306305 https://www.sciencedirect.com/science/article/pii/s0011916420306305 https://www.sciencedirect.com/science/article/pii/s0011916420306305 https://www.sciencedirect.com/science/article/pii/s0011916420306305 https://pubs.acs.org/doi/abs/10.1021/es203197e https://pubs.acs.org/doi/abs/10.1021/es203197e https://pubs.acs.org/doi/abs/10.1021/es203197e https://pubs.acs.org/doi/abs/10.1021/es203197e https://pubs.acs.org/doi/abs/10.1021/es203197e https://www.mdpi.com/620950 https://www.mdpi.com/620950 https://www.mdpi.com/620950 https://www.sciencedirect.com/science/article/pii/s037673881300865x https://www.sciencedirect.com/science/article/pii/s037673881300865x https://www.sciencedirect.com/science/article/pii/s037673881300865x https://www.sciencedirect.com/science/article/pii/s037673881300865x https://www.sciencedirect.com/science/article/pii/s0011916408000325 https://www.sciencedirect.com/science/article/pii/s0011916408000325 https://www.sciencedirect.com/science/article/pii/s0011916408000325 https://www.sciencedirect.com/science/article/pii/s0011916408000325 https://www.mdpi.com/252206 https://www.mdpi.com/252206 https://www.mdpi.com/252206 https://www.mdpi.com/252206 https://www.mdpi.com/287886 https://www.mdpi.com/287886 https://www.mdpi.com/287886 https://www.mdpi.com/287886 https://www.mdpi.com/287886 https://www.sciencedirect.com/science/article/pii/s0376738812004735 https://www.sciencedirect.com/science/article/pii/s0376738812004735 https://www.sciencedirect.com/science/article/pii/s0376738812004735 https://www.sciencedirect.com/science/article/pii/s0376738812004735 https://pubs.acs.org/doi/abs/10.1021/es100901n https://pubs.acs.org/doi/abs/10.1021/es100901n https://pubs.acs.org/doi/abs/10.1021/es100901n https://pubs.acs.org/doi/abs/10.1021/es100901n https://www.sciencedirect.com/science/article/pii/s0376738817306361 https://www.sciencedirect.com/science/article/pii/s0376738817306361 https://www.sciencedirect.com/science/article/pii/s0376738817306361 https://www.sciencedirect.com/science/article/pii/s0376738817306361 f. a. yaseen et. al / iraqi journal of chemical and petroleum engineering 23,3 (2022) 1 9 8 [16] n. y. yip et al., “thin-film composite pressure retarded osmosis membranes for sustainable power generation from salinity gradients,” environmental science and technology, vol. 45, no. 10, pp. 4360– 4369, 2011. [17] d. xiao, w. li, s. chou, r. wang, and c. y. tang, “a modeling investigation on optimizing the design of forward osmosis hollow fiber modules,” journal of membrane science, vol. 392–393, pp. 76– 87, 2012. [18] s. shen, s. e. kentish, and g. w. stevens, “shell-side mass-transfer performance in hollow-fiber membrane contactors,” solvent extraction and ion exchange, vol. 28, no. 6, pp. 817–844, 2010. [19] t. t. liang and r. l. long, “corrections to correlations for shell-side mass-transfer coefficients in the hollow-fiber membrane (hfm) modules,” industrial and engineering chemistry research, vol. 44, no. 20, pp. 7835–7843, 2005. [20] s. zhang, f. fu, and t. s. chung, “substrate modifications and alcohol treatment on thin film composite membranes for osmotic power,” chemical engineering science, vol. 87, pp. 40–50, 2013. [21] y. chen, c. heng, l. zhang, l. setiawan, and q. she, “module scale-up and performance evaluation of thin fi lm composite hollow fi ber membranes for pressure retarded osmosis,” journal of membrane science, vol. 548, no. august 2017, pp. 398–407, 2018. [22] k. l. lee, r. w. baker, and h. k. lonsdale, “membranes for power generation by pressureretarded osmosis,” journal of membrane science, vol. 8, no. 2, pp. 141–171, 1981. [23] k. touati, “energy generation and recovery by pressure retarded osmosis (pro): modeling and experiments,” 2015. [24] d. bharadwaj, t. m. fyles, and h. struchtrup, “multistage pressure-retarded osmosis,” journal of non-equilibrium thermodynamics, vol. 41, no. 4, pp. 327–347, 2016. [25] q. ge, m. ling, and t. s. chung, “draw solutions for forward osmosis processes: developments, challenges, and prospects for the future,” journal of membrane science, vol. 442, pp. 225–237, 2013. [26] f. a. yaseen, a. f. al-alawy, and a. sharif, “highly-charged edta-2na salt as a novel draw solution in pressure-retarded osmosis process,” aip conference proceedings, vol. 2372, no. november, 2021. [27] q. she, y. k. w. wong, s. zhao, and c. y. tang, “organic fouling in pressure retarded osmosis: experiments, mechanisms and implications,” journal of membrane science, vol. 428, pp. 181–189, 2013. https://pubs.acs.org/doi/abs/10.1021/es104325z https://pubs.acs.org/doi/abs/10.1021/es104325z https://pubs.acs.org/doi/abs/10.1021/es104325z https://pubs.acs.org/doi/abs/10.1021/es104325z https://pubs.acs.org/doi/abs/10.1021/es104325z https://www.sciencedirect.com/science/article/pii/s0376738811008970 https://www.sciencedirect.com/science/article/pii/s0376738811008970 https://www.sciencedirect.com/science/article/pii/s0376738811008970 https://www.sciencedirect.com/science/article/pii/s0376738811008970 https://www.sciencedirect.com/science/article/pii/s0376738811008970 https://www.tandfonline.com/doi/abs/10.1080/07366299.2010.515176 https://www.tandfonline.com/doi/abs/10.1080/07366299.2010.515176 https://www.tandfonline.com/doi/abs/10.1080/07366299.2010.515176 https://www.tandfonline.com/doi/abs/10.1080/07366299.2010.515176 https://pubs.acs.org/doi/abs/10.1021/ie040265c https://pubs.acs.org/doi/abs/10.1021/ie040265c https://pubs.acs.org/doi/abs/10.1021/ie040265c https://pubs.acs.org/doi/abs/10.1021/ie040265c https://pubs.acs.org/doi/abs/10.1021/ie040265c https://www.sciencedirect.com/science/article/pii/s0009250912005817 https://www.sciencedirect.com/science/article/pii/s0009250912005817 https://www.sciencedirect.com/science/article/pii/s0009250912005817 https://www.sciencedirect.com/science/article/pii/s0009250912005817 https://www.sciencedirect.com/science/article/pii/s0376738817324705 https://www.sciencedirect.com/science/article/pii/s0376738817324705 https://www.sciencedirect.com/science/article/pii/s0376738817324705 https://www.sciencedirect.com/science/article/pii/s0376738817324705 https://www.sciencedirect.com/science/article/pii/s0376738817324705 https://www.sciencedirect.com/science/article/pii/s0376738817324705 https://www.sciencedirect.com/science/article/pii/s0376738800820888 https://www.sciencedirect.com/science/article/pii/s0376738800820888 https://www.sciencedirect.com/science/article/pii/s0376738800820888 https://www.sciencedirect.com/science/article/pii/s0376738800820888 https://uvadoc.uva.es/handle/10324/16049 https://uvadoc.uva.es/handle/10324/16049 https://uvadoc.uva.es/handle/10324/16049 https://www.degruyter.com/document/doi/10.1515/jnet-2016-0017/html https://www.degruyter.com/document/doi/10.1515/jnet-2016-0017/html https://www.degruyter.com/document/doi/10.1515/jnet-2016-0017/html https://www.degruyter.com/document/doi/10.1515/jnet-2016-0017/html https://www.sciencedirect.com/science/article/pii/s0376738813002494 https://www.sciencedirect.com/science/article/pii/s0376738813002494 https://www.sciencedirect.com/science/article/pii/s0376738813002494 https://www.sciencedirect.com/science/article/pii/s0376738813002494 https://www.sciencedirect.com/science/article/pii/s0376738813002494 https://aip.scitation.org/doi/abs/10.1063/5.0066125 https://aip.scitation.org/doi/abs/10.1063/5.0066125 https://aip.scitation.org/doi/abs/10.1063/5.0066125 https://aip.scitation.org/doi/abs/10.1063/5.0066125 https://aip.scitation.org/doi/abs/10.1063/5.0066125 https://www.sciencedirect.com/science/article/pii/s0376738812007892 https://www.sciencedirect.com/science/article/pii/s0376738812007892 https://www.sciencedirect.com/science/article/pii/s0376738812007892 https://www.sciencedirect.com/science/article/pii/s0376738812007892 f. a. yaseen et. al / iraqi journal of chemical and petroleum engineering 23,3 (2022) 1 9 9 نمذجة رياضية لوحدة األلياف المجوفة المستخدمة في عملية تناضح الضغط الُمثبَّط عادل شريف 3أحمد فائق العلوي, 2فرح عادل ياسين, 1 شركة النفط الوطنية العراقية, شركة نفط الوسط, بغداد, العراق 1 قسم الهندسة الكيمياوية, كلية الهندسة, جامعة بغداد, بغداد, العراق 2 قسم هندسة العمليات والهندسة الكيميائية, جامعة سري، سري، المملكة المتحدة 3 الخالصة كإحدى طرق استخدام طاقة التناضح ، وهي تقنية (pro) يمكن اعتبار عملية تناضح الضغط الُمثبَّط لتوليد الطاقة. في pro شاء. تلعب النمذجة الرياضية دوًرا أساسًيا في تطوير وتحسين أنظمةتعتمد على الغ هذا البحث ، تم تطوير نموذج رياضي لوحدة األلياف المجوفة للتنبؤ بكثافة الطاقة و َتَدُفق الماء نظرًيا. تم امل تشغيل مختلفة, تركيز استخدام محلول كلوريد الصوديوم كمحلول تغذية ومحلول سحب. تم استخدام عو لتر / دقيقة(، فرق الضغط 4، و 3، 2موالري( ، ومعدل تدفق محلول السحب ) 2و 1محلول السحب ) لوحدة األلياف المجوفة. تم دراسة تأثير هذه pro بار( لتقييم أداء عملية 90-0الهيدروليكي المطبق ) المتغيرات التشغيلية على تدفق المياه وكثافة الطاقة النظرية. وفًقا للنتائج النظرية ، زاد تدفق الماء المتخلل وكثافة الطاقة مع زيادة تركيز محلول السحب ومعدل تدفق محلول السحب. بينما انخفض تدفق الماء المتخلل التغذية. بزيادة الضغط الهيدروليكي المطبق على محلول السحب ، محلول تركيز زيادة معة وكثافة الطاق انخفض تدفق الماء وزادت كثافة الطاقة الناتجة. كانت كثافة الطاقة القصوى وتدفق الماء المتخلل حوالي ري كلوريد موال 2على التوالي عند استخدام محلول سحب .ساعة 2م\لتر 11.818و 2واط/م 16.414 .بار 50الصوديوم ، والذي يحدث عند ضغط هيدروليكي مطبق قدره الكلمات الدالة: النموذج الرياضي ، طاقة التناضح ، غشاء ليفي مجوف ، تناضح الضغط الُمثبَّط. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.20 no.4 (december 2019) 7 – 13 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: sama m. al-jubouri , email: sama.al-jubouri@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. the static aging effect on the seedless synthesis of different ranges faujasite-type zeolite y at various factors sama m. al-jubouri department of chemical engineering college of engineering university of baghdad baghdad iraq abstract this work focuses on the formation of a pure phase faujasite-type zeolite y via a static aging step in the absence of seeds at the ranges chosen for this study. nano-sized crystals of y zeolite were successfully obtained when ludox as-40 was used as a silica source for gel composition of range 6 and crystallization wasconducted for a period of 4 to 19 hr at 100⁰c with surface area of 672 m 2 /g. moreover, large-crystals with high crystallinity pure phase y zeolite (with surface area of 682 m 2 /g) can be obtained here at the above conditions but when hydrous sodium metasilicate was used as a silica source. the most significant outcome of this study is that static aging effectively leads to obtaining a pure phase y zeolite for all selected ranges at controlled conditions in a seedless synthesis. keywords: faujasite-type, static aging, seedless synthesis, zeolite, hydrothermal treatment received on 02/09/2019, accepted on 15/10/2019, published on 30/12/1029 https://doi.org/10.31699/ijcpe.2019.4.2 1introduction zeolites are microporous crystalline aluminosilicates minerals composed of open-framework structures containing channels and cages of molecular level which are accessible by other molecules[1, 2].the fully crosslinked open framework of zeolites composed of sio4tetrahedron and alo4 tetrahedron linked to each other by sharing oxygen atoms; and zeolites’ channels and cages are occupied by water molecules[3]. also, the cavities and cages of zeolites are occupied by cations such as sodium, calcium, potassium or organic cations to balance the negative charge generated due to the alo4 tetrahedron substitutions on the zeolite’s framework[4, 5]. zeolites are different types categorized either according to si/al ratio or framework structure[3]. generally, faujasite (fau) zeolites are divided into two types which are zeolite nax with low si/al ratio (below 1.5) and zeolite nay with intermediate si/al ratio (1.5-3[6]and can be greater than 3[7]). zeolite y is a versatile used zeolite from the faujasite family featured of a framework constructed of double 6rings connected through sodalite cages. this connection generates large supercages with 12-ring aperture which is accessible by pores with an average diameter of 7.4 å[8]. typically, the unit cell of y zeolite is cubic (a = 24.7å) with fd-3m symmetry and thermally decomposes at 793ºc[9]. zeolite y is an important intermediate and often high silica zeolite which is broadly used as an adsorbent, ion exchanger, catalyst and others[10–12]. y zeolite has been extensively used as a catalyst for fluid catalytic cracking (fcc) and as a selective adsorbent for volatile organic and gaseous emissions removal and hydrocarbons purification [3, 15]. the vital role of y zeolite in many chemical industries is due to zeolites’ microporous structure providing excellent shape selectivity, large surfaces, strong brønsted acid sites, favorable thermal and hydrothermal stability and reasonable low cost [13, 14]. also, the open negatively charged framework containing easily exchangeable cations makes y zeolite being utilized for potential environmental application such as heavy metal cations removal from industrial wastewater[16, 17]. synthesis of zeolites encompasses of preparing aluminosilicate precursor solution from mixing of chemicals (aluminum source and silica source) under the alkaline conditions, aging the aluminosilicate solution and crystallizing the precursor solution for specific times at high temperatures[1, 18].for some cases, aging step accelerates nucleation, enhances degree of crystallization and increases the silica to alumina ratio. aging works on incorporating more silica into aluminosilicate framework even at low level of alkalinity. aging affects the kinetics of nucleation and crystallization through increasing the population of the final product and reducing the induction period and crystallization time [11, 19]. kovo and holmes [20]obtained that aging significantly increased the crystallinity of the final y zeolite crystals. https://doi.org/10.31699/ijcpe.2019.4.2 s. m. al-jubouri / iraqi journal of chemical and petroleum engineering 20,4 (2019) 7 13 8 producing zeolite with desired properties depends on various important variables such as, alkalinity, the source of the precursor gel, aging, crystallization temperature and time, and organic additives (template), etc. choosing the right experiment conditions achieves pure form of the desired zeolite and prevents transition from one structure/symmetry into another structure/symmetry, and emergence of the intermediate phases[8]. therefore, several previous works [3, 9, 21, 22] recommended using seeds derived from y zeolite either in the presence or absence of aging step for synthesizing pure phase y zeolite. however, utilization of seeds made of counterpart phases to natural zeolites in the preparation adds cost to the cost of the preparation process. for cost-effective preparation process of pure y zeolite, this work investigates introducing static aging (ripening) step to prepare y zeolite with a gel formula chosen from different ranges. also,it deals with studying the effect of crystallization time and the silica source on the growth of y zeolite. 2experimental work 2.1. chemicals the used silica sources were sodium metasilicates (10.6%wt. na2o and 26.5%wt. sio2, sigma-aldrich), fumed silica (99.8%wt.sigma-aldrich) and ludox as40 (sigma-aldrich). alumina source was anhydrous sodium aluminate (55-56%wt. al2o3, riedel-dehan) and sodium hydroxide (99.9%wt. from fisher scientific) was a cation source. commercial nayzeolite (sigma-aldrich) with si/al of 2.28 and an average crystal size of 1268.7 nm was used for comparison with products. deionized water with conductivity of 2 µs was used for zeolite preparation. 2.2. synthesis and characterization of fau-type zeolite y preparation of y zeolite samples was started with preparing alkali solution from mixing a certain weight of naoh with a volume of deionized water. the quantities and volume of chemicals used for preparation were specified according to the formula of the mother gel chosen from a previous study[23]. table 1 displays the chosen ranges for y zeolite preparation. table 1. ranges of y zeolite chosen according to[23] range sio2/al2o3 na2o/sio2 h2o/na2o 2 10-30 0.41-0.6 20-60 3 7-30 0.61-0.8 20-60 6 10-30 1.5-1.7 20-90 9 10-20 1.5-1.7 20-125 11 10-27 0.4 30-50 then, the synthesis accomplished by adding alumina source to the alkali solution prepared previously and mixed until obtaining a clear solution. after that, silica source was added to the combination and mixed for 15 min. to study the effect of static aging, the produced gel was placed in an autoclave and left to age for 24 hr. the gel then was hydrothermally crystallized at 100⁰c for19 hr. also, the effect of crystallization time was investigated at 100⁰c for time range of 4-24 hr. also, one more sample was prepared by addingy zeolite seeds to a sample of range 6 (r6) and mixed for 2 hours before crystallization without aging. the seeds were commercial y zeolite (provided by sigma-aldrich) equals to 5% wt of silica source used to prepare the sample. the x-ray pattern, elemental analysis and morphology of commercial y zeolite are shown in fig. 1 and fig. 2. fig. 1. xray pattern of the commercial y zeolite fig. 2. sem image of the commercial y zeolite moreover, another sample was prepared according to [24]. this way encompasses preparing seeds gel and feedstock gel. then, the overall gel is obtained by adding a certain amount of seeds gel containing 5% of al in the overall zeolite formula to a specific amount of feedstock gel containing 95% of al in the overall zeolite formula. s. m. al-jubouri / iraqi journal of chemical and petroleum engineering 20,4 (2019) 7 13 9 seeds gel: 10.67 na2o: al2o3: 10 sio2:180 h2o (r5) feedstock gel: 4.30 na2o: al2o3: 10 sio2: 180 h2o (r2) overall gel: 4.62 na2o: al2o3: 10 sio2: 180 h2o (r11) once the crystallization completes, the products were separated, rinsed with deionized water to reduce the ph of the outlet water to below 9. after that, the products were dried 70-80°c, collected and characterized. the phase of product was identified using x-ray diffraction (xrd) conducted via a rigakuminiflex diffractor meter (cuka radiation, 30 kv, 15 ma, k = 1.5418 å). the morphology of the products was obtained using scanning electron microscopy (sem, fei quanta 200 environmental). the composition of the elements composing the specimen was provided by the energy dispersive analysis by x-ray (edax).the crystal size of samples was obtained usingimagej software[25]depending onthe sem images. the samples prepared from different silica source were also characterized using fourier transform infrared (irprestige-21, shimadzu) spectrophotometer to obtain fourier transformed infrared (ftir) spectrum. the samples were scanned in the wavelength range of 4000 400 cm -1 . also, the surface area was measured for those two samples using brunauer-emmett-teller (bet) method based on the n2-adsorptio/desorption isotherms at -196⁰c. this characterization was conducted via micrometrics asap 2020 after degassing at 200⁰c for 1hr under vacuum pressure. 3results and discussion the results of this study have been compared to the data of commercial y zeolite. also, the crystallinity of all samples was calculated relative to commercial y zeolite at the strongest peaks of 2θ of 6.23, 15.65, 23.63, 27.02 and 31.4according to equation 1 as given by van bekkum et al.,[26]. (1) fig. 3 presents xray patterns of y zeolite produced using three different ways. the three samples exhibited patterns identical to the commercial zeolite with no strange peaks. however, the sample prepared using seeds gel showed higher crystallinity than a sample prepared using seeds powder, which can be attributed to the controlled conditions used to prepare the seeds gel compared to the conditions used to prepare the commercial zeolite. also, aging the seeds solution for 24 hr allows formation enough nuclei for growing zeolite with ordered crystals as shown in fig. 4 (b). comparatively, the morphology of the sample prepared with powder seeds has irregular shape and size as shown in fig. 4 (a).while, the sample prepared without seeds after static agingshowed full crystallized and regular size crystals. fig. 3. xraypattern of y zeolite prepared using (a) powder seeds of y zeolite, (b) seedsgel of y zeolite, (c) static aging without seeds. crystallization temperature of 100⁰c and crystallization time 19 hr fig. 4. sem images ofy zeolite prepared using (a) powder seeds of y zeolite, (b) seeds gel of y zeolite, (c) static aging without seeds. crystallization temperature of 100⁰c and crystallization time 19 hr the average crystal size of the sample prepared using seeds powder is smaller than the average size of the sample prepared using seeds gel as shown in table 2. which can be attributed to the large surface area provided by the seeds powder which promotes the nucleation, but short crystallization with large nucleation rate leads to different size crystals. however, aging the reaction gel for 24 hr promotes the quick formation of numerous nuclei and growing of small size crystals from the same nutrition[27]. also, the synthesis way did not affect the si/al ratio of the produced zeolite as all possessed si/al > 1.5. table 2. elements analysis and crystal size of y zeolite prepared using different preparation ways synthesis technique %wt o %wt na %wt al %wt si si/al average crystal size (nm) crystallinity % powder seeds of y zeolite 45.8 11.71 15.77 26.7 1.7 2737.75 75.15 seeds gel of y zeolite 47.6 7.47 13.61 31.3 2.3 2337.85 above 100 static aging without seeds 49.1 3 9.25 15.62 5 26 1.66 1545.8 100 s. m. al-jubouri / iraqi journal of chemical and petroleum engineering 20,4 (2019) 7 13 01 the results displaying the effect of crystallization time on the final product are shown in fig. 5, fig. 6 and table 3. the results given by xrd show that crystallization of y zeolite at 4 hrproduced full crystallized product because the pattern has a flat background. the crystallinity of product started with 77.16% at 4 hrand then it increased with time until it reached to the maximum (100%) at 19 hr; after that it reduced at 24 hr. ripening process of the gel allows quick gel conversion and crystallization within a short induction time at high crystallization temperature[19]. the average crystal size shown in table 3 are close for different crystallization time periods because all were crystallized after aging which reduces the crystal size and increases the crystal population. the effect of aging is predominant over the effect of time. this phenomenon occurred for all except for the crystallization of 4 and 14 h, they showed smaller but approximately similar average crystal size (473.35 and 455.4 nm, respectively). fig. 5. xray pattern of y zeolite (r6) prepared from ludox as-40 at static aging without seeds conditions and crystallization temperature of 100⁰c for (a) 4 hr, (b) 9 hr, (c) 14 hr, (d) 19 hr, (e) 24 hr fig. 6. sem images ofy zeolite (r6) prepared from ludox as-40 at static aging without seeds conditions and crystallization temperature of 100⁰c for (a) 4 hr, (b) 9 hr, (c) 14 hr, (d) 19 hr, (e) 24 hr table 3. elements analysis and crystal size of y zeolite (r6) prepared using static aging without seeds conditions at different crystallization time crystallization time (hr) %wt o %wt na %wt al %wt si si/al average crystal size (nm) crystallinity% 4 45.56 9.05 16.29 29.01 1.78 473.35 77.16 9 48.04 9.5 15.12 27.34 1.81 558.25 86 14 46.59 8.75 15.98 28.68 1.8 455.4 100 19 49.13 9.25 15.625 26 1.66 568.95 100 24 47.2 8.77 15.54 28.5 1.83 558.65 75.28 fig. 7, fig. 8 and table 4 present the effect of aging on crystallization of different ranges of y zeolite. xdr patterns shown in fig. 7 shows successful crystallization was obtained for the chosen ranges because no peak irrelevant to faujasite appeared for all samples. this result was confirmed by edax results presented in table 4, since all samples possess si/al > 1.5; but, they ended with different average size of crystal. the product of r11, r2 and r3 gave larger sizes of 852.8, 820.3 and 811.2 nm, respectively; followed by r9 with an average crystal size of 705.25nm and the smaller average size was obtained by r6 of 568.95 nm. accordingly, it is worth to mention that aging helped for obtaining nanosized crystals for the chosen ranges of y zeolite. fig. 7. xraypattern of y zeolite prepared from ludox as-40 at static aging without seeds conditions and crystallization temperature of 100⁰c for 19 hr. (a) range 11, (b) range 6, (c) range 9, (d) range 2, (e) range 3 fig. 8. sem images ofy zeolite prepared from ludox as-40 at static aging without seeds conditions and crystallization temperature of 100⁰c for 19 hr. (a) range 11, (b) range 6, (c) range 9, (d) range 2, (e) range 3 s. m. al-jubouri / iraqi journal of chemical and petroleum engineering 20,4 (2019) 7 13 00 table 4. elements analysis and crystal size of y zeolite prepared using static aging without seeds conditions for different y zeolite ranges zeolite y range %wt o %wt na %wt al %wt si si/al average crystal size (nm) crystallinity% range 11 51.08 7.45 12.55 28.0 2.3 852.8 96.36 range 6 49.13 9.25 15.625 26 1.66 568.95 90 range 9 47.56 6.55 13.55 32.34 2.4 705.25 89 range 2 48.22 9.22 15.11 27.44 1.82 820.3 93 range 3 46.54 6.84 12.685 33.94 2.68 811.2 61 the results presenting the effect of silica source on the growing zeolite prepared with r6 are shown in fig. 9, fig. 10 and table 5. the xrd pattern shown in fig. 9 indicates that y zeolite grown from hydrous sodium metasilicates showed higher crystallinity than this given by ludox as-40. this can be attributed to its occurring with low supersaturation which leads to grow large crystals at the expense of nucleation. thus, the sample prepared from hydrous sodium metasilicates produced larger size crystals as shown in table 5 while, using fumed silica as a silica source produced glassy solid with no defined phase, therefore its pattern was not presented here. fig. 9. xray pattern of y zeolite prepared with r6using (a) hydrous sodium metasilicates, (b) ludox as-40. crystallization temperature of 100⁰c and crystallization time 19 hr fig. 10. sem images of y zeolite prepared with r6 using (a) hydrous sodium metasilicates, (b) ludox as-40 crystallization temperature of 100⁰c and crystallization time 19 hr. table 5. elements analysis and crystal size of y zeolite prepared with r6using different silica sources silica source %wt o %wt na %wt al %wt si si/al average crystal size (nm) crystallinity% hydrous sodium metasilicates 46.6 8.74 15.8 28.83 1.82 1545.8 above 100 ludox as40 49.13 9.25 15.625 26 1.66 811.2 100 ftir spectra of both samples prepared from hydrous sodium metasilicates and ludox as-40 are shown in fig. 11 and fig. 12, respectively. generally, more bands vibrated for the samples prepared from ludox as-40. several peaks are common between the samples which are 1384.89, 999.13, 690.52, 617.22, 570.93, 528.50 and 478.35 cm -1 . the figures show broad peaks appeared at 3479.58 and 3468.01 cm -1 due to the presence of o-h stretch. also, three peaks appeared at the range of 160-3500 cm -1 for the sample prepared from hydrous sodium metasilicates as shown in fig. 11 and four peaks appeared at the same range here in above for the samples prepared from ludox as-40 as shown in fig. 12 due to the presence of zeolite water. the sample prepared from ludox as-40 showed a peak at 1246.02 cm -1 attributed to vibration of internal sio-si and si-o-al tetrahedron. due to the vibration of the same bonds (si-o-si and si-o-al tetrahedron), both samples showed peaks at 999.13cm -1 . bands appearing in the range 650-900 cm -1 are related with symmetric stretching vibration of t-o tetrahedron. in the bands range 520-650 cm -1 , a group of peaks appeared due to pseudo-lattice vibration. however, the peaks appeared in the range of 400-500 cm -1 are associated with t-o symmetric stretching of the internal si-o-si and si-o-al tetrahedran. fig. 11. ftir spectrum of zeolite nayprepared with r6usinghydrous sodium metasilicates and crystallized at 100 ⁰c for 19 hr s. m. al-jubouri / iraqi journal of chemical and petroleum engineering 20,4 (2019) 7 13 01 fig. 12. ftir spectrum of zeolite nayprepared with r6usingludox as-40 and crystallized at 100 ⁰c for 19 hr the surface area measured for the sample prepared from hydrous sodium metasilicate was 682 m 2 /g and for the sample prepared from ludox as-40 was672 m 2 /g. this high surface area of these samples which can be attributed to the high crystallinity of samples is industrially favorable and confirms the feasibility of the aging step for y zeolite preparation.both samples possess close surface area, but the sample prepared from hydrous sodium metasilicate gave relatively higher surface area which is compatible with its higher si/al ratio; in spite of it has larger average crystal size than the sample prepared from ludox as-40. 4conclusions this study presents the possibility of producing pure phase faujasite-type zeolite y at the ranges disclosed herein at a static aging condition in the absence of seeds. wherein, nano-sized crystals can be obtained when ludox as-40 is used as a silica source for gel composition of the preferred range 6 and the crystallization process can be carried out for a period of from 4 to 19 hr at 100⁰c. also, high crystallinelargecrystals pure phase y zeolite can be obtained at the same conditions but when hydrous sodium metasilicate is used as a silica source. however, the other selected ranges can offer pure phase y zeolite at here in the above conditions. acknowledgement the author would like to thank the higher committee for education development in iraq for financially supporting sama m. al-jubouri to conduct this work on the university of manchester labs. also, the authors would like to specifically thank prof. dr. stuart m. holmes and dr. patrick hill. references [1] aimen isa, m., chew, t.l., yeong, y.f.: zeolite nay synthesis by using sodium silicate and colloidal silica as silica source. iop conf. ser. mater. sci. eng. 458, (2018). [2] al-jubouri, s.m., de haro-del rio, d.a., alfutimie, a., curry, n.a., holmes, s.m.: understanding the seeding mechanism of hierarchically porous zeolite/carbon composites. microporous mesoporous mater. 268, 109–116 (2018). [3] wittayakun, j., khemthong, p., prayoonpokarach, s.: synthesis and characterization of zeolite nay from rice husk silica. korean j. chem. eng. 25, 861–864 (2008). [4] edanol, y., usman, k., buenviaje, s., mantua, m., payawan, l.: utilizing silica from rice hull for the hydrothermal synthesis of zeolite y. kimika. 29, 17–21 (2018). [5] al-jubouri, s.m., waisi, b.i., holmes, s.m.: rietveld texture refinement analysis of linde type a zeolite from x-ray diffraction data. j. eng. sci. technol. (2018) [6] dyer, a.: zeolites, (2001) [7] kovo, a.s., hernandez, o., holmes, s.m.: synthesis and characterization of zeolite y and zsm-5 from nigerian ahoko kaolin using a novel, lower temperature, metakaolinization technique. j. mater. chem. 19, 6207–6212 (2009) [8] azizi, s.n., daghigh, a.a., abrishamkar, m.: phase transformation of zeolite p to y and analcime zeolites due to changing the time and temperature. j. spectrosc. 2013, 1–5 (2013). [9] rahman, m.m., hasnida, n., wan nik, w.b.: preparation of zeolite y using local raw material rice husk as a silica source. j. sci. res. 1, 285–291 (2009). [10] holmberg, b. a., wang, h., norbeck, j.m., yan, y.: controlling size and yield of zeolite y nanocrystals using tetramethylammonium bromide. microporous mesoporous mater. 59, 13–28 (2003). [11] li, q., zhang, y., cao, z., gao, w., cui, l.: influence of synthesis parameters on the crystallinity and si/al ratio of nay zeolite synthesized from kaolin. pet. sci. 7, 403–409 (2010). [12] ahmedzeki, n.s., al-tabbakh, b.a.: catalytic reforming of iraqi naphtha over pt-ti / hy zeolite catalyst. iraqi j. chem. pet. eng. 17, 45–56 (2016) [13] garcía-martínez, j., li, k., krishnaiah, g.: a mesostructured y zeolite as a superior fcc catalyst – from lab to refinery. chem. commun. 48, 11841 (2012). [14] zhao, j., yin, y., li, y., chen, w., liu, b.: synthesis and characterization of mesoporous zeolite y by using block copolymers as templates. chem. eng. j. 284, 405–411 (2016). [15] bortolatto, l.b., boca santa, r.a.a., moreira, j.c., machado, d.b., martins, m.a.p.m., fiori, m.a., kuhnen, n.c., riella, h.g.: synthesis and characterization of y zeolites from alternative silicon and aluminium sources. microporous mesoporous mater. 248, 214–221 (2017). https://iopscience.iop.org/article/10.1088/1757-899x/458/1/012001/pdf https://iopscience.iop.org/article/10.1088/1757-899x/458/1/012001/pdf https://iopscience.iop.org/article/10.1088/1757-899x/458/1/012001/pdf https://iopscience.iop.org/article/10.1088/1757-899x/458/1/012001/pdf https://www.sciencedirect.com/science/article/abs/pii/s1387181118302026 https://www.sciencedirect.com/science/article/abs/pii/s1387181118302026 https://www.sciencedirect.com/science/article/abs/pii/s1387181118302026 https://www.sciencedirect.com/science/article/abs/pii/s1387181118302026 https://www.sciencedirect.com/science/article/abs/pii/s1387181118302026 https://link.springer.com/article/10.1007/s11814-008-0142-y https://link.springer.com/article/10.1007/s11814-008-0142-y https://link.springer.com/article/10.1007/s11814-008-0142-y https://link.springer.com/article/10.1007/s11814-008-0142-y https://kimika.pfcs.org.ph/index.php/kimika/article/view/253/206 https://kimika.pfcs.org.ph/index.php/kimika/article/view/253/206 https://kimika.pfcs.org.ph/index.php/kimika/article/view/253/206 https://kimika.pfcs.org.ph/index.php/kimika/article/view/253/206 http://jestec.taylors.edu.my/vol%2013%20issue%2012%20december%202018/13_12_13.pdf http://jestec.taylors.edu.my/vol%2013%20issue%2012%20december%202018/13_12_13.pdf http://jestec.taylors.edu.my/vol%2013%20issue%2012%20december%202018/13_12_13.pdf https://pubs.rsc.org/en/content/articlelanding/2009/jm/b907554b/unauth#!divabstract https://pubs.rsc.org/en/content/articlelanding/2009/jm/b907554b/unauth#!divabstract https://pubs.rsc.org/en/content/articlelanding/2009/jm/b907554b/unauth#!divabstract https://pubs.rsc.org/en/content/articlelanding/2009/jm/b907554b/unauth#!divabstract https://pubs.rsc.org/en/content/articlelanding/2009/jm/b907554b/unauth#!divabstract doi:10.1155/2013/428216 doi:10.1155/2013/428216 doi:10.1155/2013/428216 doi:10.1155/2013/428216 https://www.banglajol.info/index.php/jsr/article/view/1777 https://www.banglajol.info/index.php/jsr/article/view/1777 https://www.banglajol.info/index.php/jsr/article/view/1777 https://www.sciencedirect.com/science/article/abs/pii/s1387181103002713 https://www.sciencedirect.com/science/article/abs/pii/s1387181103002713 https://www.sciencedirect.com/science/article/abs/pii/s1387181103002713 https://www.sciencedirect.com/science/article/abs/pii/s1387181103002713 https://link.springer.com/article/10.1007/s12182-010-0085-x https://link.springer.com/article/10.1007/s12182-010-0085-x https://link.springer.com/article/10.1007/s12182-010-0085-x https://link.springer.com/article/10.1007/s12182-010-0085-x http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/212 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/212 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/212 https://pubs.rsc.org/en/content/articlelanding/2012/cc/c2cc35659g/unauth#!divabstract https://pubs.rsc.org/en/content/articlelanding/2012/cc/c2cc35659g/unauth#!divabstract https://pubs.rsc.org/en/content/articlelanding/2012/cc/c2cc35659g/unauth#!divabstract https://pubs.rsc.org/en/content/articlelanding/2012/cc/c2cc35659g/unauth#!divabstract https://www.sciencedirect.com/science/article/pii/s1385894715012395 https://www.sciencedirect.com/science/article/pii/s1385894715012395 https://www.sciencedirect.com/science/article/pii/s1385894715012395 https://www.sciencedirect.com/science/article/pii/s1385894715012395 https://www.sciencedirect.com/science/article/abs/pii/s1387181117302706 https://www.sciencedirect.com/science/article/abs/pii/s1387181117302706 https://www.sciencedirect.com/science/article/abs/pii/s1387181117302706 https://www.sciencedirect.com/science/article/abs/pii/s1387181117302706 https://www.sciencedirect.com/science/article/abs/pii/s1387181117302706 https://www.sciencedirect.com/science/article/abs/pii/s1387181117302706 s. m. al-jubouri / iraqi journal of chemical and petroleum engineering 20,4 (2019) 7 13 02 [16] gazola, f.c., pereira, m.r., barros, m. a s.d., silva, e. a., arroyo, p. a.: removal of cr3+ in fixed bed using zeolite nay. chem. eng. j. 117, 253–261 (2006). [17] ostroski, i.c., barros, m.a.s.d., silva, e.a., dantas, j.h., arroyo, p.a., lima, o.: a comparative study for the ion exchange of fe (iii) and zn (ii) on zeolite nay. j. hazard. mater. 161, 1404–1412 (2009) [18] al-jubouri, s.m., adil, h., lafta, h.a., waisi, b.i.: effect of synthesis parameters on the formation 4a zeolite crystals : characterization analysis and heavy metals uptake performance study for water treatment. 165, 290–300 (2019). [19] cejka, j., van bekkum, h., corma, a., schüth, f. eds: introduction to zeolite science and practice. elsevier, uk (2007) [20] kovo, a.s., holmes, s.m.: effect of aging on the synthesis of kaolin-based zeolite y from ahoko nigeria using a novel metakaolinization technique. j. dispers. sci. technol. 31, 442–448 (2010). [21] yusof, a.m., nizam, n.a., rashid, n.a.a.: hydrothermal conversion of rice husk ash to faujasitetypes and naa-type of zeolites. j. porous mater. 17, 39–47 (2010). [22] tan, w.-c., yap, s.-y., matsumoto, a., othman, r., yeoh, f.-y.: synthesis and characterization of zeolites naa and nay from rice husk ash. adsorption. 17, 863–868 (2011). [23] breck, d.w.: crystalline zeolite y, (1964) [24] robson, h.: verified synthesis of zeolitic materials. elsevier science (2001) [25] image processing and analysis in java: imagej. software [26] h. van bekkum, e.m. flanigen, k.j.: introduction to zeolite science and practice, studies in surface science and catalysis 137. elsevier science b.v, delft (2001) [27] byrappa, k., yoshimura, m.: handbook of hydrothermal technology. elsevier, new york (2013) بغياب البذور تحت عوامل fauزيوليت تصنيع مدى واسع منالساكنة عمى تعميرتأثير ال مختمفة سما محمد الجبوري العراق-بغداد-جامعة بغداد-كمية اليندسة-الكيمياويةقسم اليندسة الخالصة النقي بأستخدام مرحمة التنضيج الساكنة في غياب faujasiteيركز ىذا العمل عمى تكوين زيوليت من نوع كمصدر لمسيميكا ludox as-40البذور ضمن الحدود المختارة. تم أنتاج بمورات بحجم النانو عند استخدام مئوية. عالوة عمى ذلك ، تم 911ساعة بدرجة حرارة 91إلى 4وبمورتو لمدة من 2لتكوين اليالم في المدى عالي النقاوة في الظروف المذكورة أعاله ولكن عند استخدام yالحصول عمى بمورات كبيرة من الزيوليت جة تم التوصل ليا من ىذه الدراسة ىي التنضيج الساكن ميتاسيميكات الصوديوم المائي كمصدر لمسيميكا. أىم نتي نقي في نفس الظروف المتحكم فييا لجميع الحدود األخرى yيؤدي بكفاءة الى الحصول عمى طور زيوليت المختارة أيًضا لعممية التصنيع بغياب البذور. زيواليت, معاممة ىيدروحرارية, تعمير ساكن, تصنيع بغياب البذور, faujasiteالكممات الدالة: نوع https://www.sciencedirect.com/science/article/pii/s1385894705004961 https://www.sciencedirect.com/science/article/pii/s1385894705004961 https://www.sciencedirect.com/science/article/pii/s1385894705004961 https://www.sciencedirect.com/science/article/pii/s1385894705004961 %5b17%5d%09ostroski,%20i.c.,%20barros,%20m.a.s.d.,%20silva,%20e.a.,%20dantas,%20j.h.,%20arroyo,%20p.a.,%20lima,%20o.:%20a%20comparative%20study%20for%20the%20ion%20exchange%20of%20fe%20(iii)%20and%20zn%20(ii)%20on%20zeolite%20nay.%20j.%20hazard.%20mater.%20161,%201404–1412%20(2009) %5b17%5d%09ostroski,%20i.c.,%20barros,%20m.a.s.d.,%20silva,%20e.a.,%20dantas,%20j.h.,%20arroyo,%20p.a.,%20lima,%20o.:%20a%20comparative%20study%20for%20the%20ion%20exchange%20of%20fe%20(iii)%20and%20zn%20(ii)%20on%20zeolite%20nay.%20j.%20hazard.%20mater.%20161,%201404–1412%20(2009) %5b17%5d%09ostroski,%20i.c.,%20barros,%20m.a.s.d.,%20silva,%20e.a.,%20dantas,%20j.h.,%20arroyo,%20p.a.,%20lima,%20o.:%20a%20comparative%20study%20for%20the%20ion%20exchange%20of%20fe%20(iii)%20and%20zn%20(ii)%20on%20zeolite%20nay.%20j.%20hazard.%20mater.%20161,%201404–1412%20(2009) %5b17%5d%09ostroski,%20i.c.,%20barros,%20m.a.s.d.,%20silva,%20e.a.,%20dantas,%20j.h.,%20arroyo,%20p.a.,%20lima,%20o.:%20a%20comparative%20study%20for%20the%20ion%20exchange%20of%20fe%20(iii)%20and%20zn%20(ii)%20on%20zeolite%20nay.%20j.%20hazard.%20mater.%20161,%201404–1412%20(2009) 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https://link.springer.com/article/10.1007/s10934-009-9262-y https://link.springer.com/article/10.1007/s10934-009-9262-y https://link.springer.com/article/10.1007/s10450-011-9350-6 https://link.springer.com/article/10.1007/s10450-011-9350-6 https://link.springer.com/article/10.1007/s10450-011-9350-6 https://link.springer.com/article/10.1007/s10450-011-9350-6 https://patents.google.com/patent/us3130007a/en https://books.google.iq/books?hl=en&lr=&id=nsnvdthj2dsc&oi=fnd&pg=pa1&dq=%5b24%5d%09robson,+h.:+verified+synthesis+of+zeolitic+materials.+elsevier+science+(2001)&ots=smem9cqkzv&sig=qyeshx1sjxxeizz83choobfm-mi&redir_esc=y#v=onepage&q=%5b24%5d%09robson%2c%20h.%3a%20verified%20synthesis%20of%20zeolitic%20materials.%20elsevier%20science%20(2001)&f=false 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https://books.google.iq/books?hl=en&lr=&id=usle2xgd8noc&oi=fnd&pg=pp1&dq=%5b26%5d%09h.+van+bekkum,+e.m.+flanigen,+k.j.:+introduction+to+zeolite+science+and+practice,+studies+in+surface+science+and+catalysis+137.+elsevier+science+b.v,+delft+(2001)&ots=rbzuasykm_&sig=voyjehotbkheqj18dj5iemfv-qk&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=usle2xgd8noc&oi=fnd&pg=pp1&dq=%5b26%5d%09h.+van+bekkum,+e.m.+flanigen,+k.j.:+introduction+to+zeolite+science+and+practice,+studies+in+surface+science+and+catalysis+137.+elsevier+science+b.v,+delft+(2001)&ots=rbzuasykm_&sig=voyjehotbkheqj18dj5iemfv-qk&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=usle2xgd8noc&oi=fnd&pg=pp1&dq=%5b26%5d%09h.+van+bekkum,+e.m.+flanigen,+k.j.:+introduction+to+zeolite+science+and+practice,+studies+in+surface+science+and+catalysis+137.+elsevier+science+b.v,+delft+(2001)&ots=rbzuasykm_&sig=voyjehotbkheqj18dj5iemfv-qk&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=va5txzlshioc&oi=fnd&pg=pp1&dq=%5b27%5d%09byrappa,+k.,+yoshimura,+m.:+handbook+of+hydrothermal+technology.+elsevier,+new+york+(2013)&ots=cxrh6piknj&sig=mzavhw5fwgdkwj8x34w_fdiumxm&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=va5txzlshioc&oi=fnd&pg=pp1&dq=%5b27%5d%09byrappa,+k.,+yoshimura,+m.:+handbook+of+hydrothermal+technology.+elsevier,+new+york+(2013)&ots=cxrh6piknj&sig=mzavhw5fwgdkwj8x34w_fdiumxm&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=va5txzlshioc&oi=fnd&pg=pp1&dq=%5b27%5d%09byrappa,+k.,+yoshimura,+m.:+handbook+of+hydrothermal+technology.+elsevier,+new+york+(2013)&ots=cxrh6piknj&sig=mzavhw5fwgdkwj8x34w_fdiumxm&redir_esc=y#v=onepage&q&f=false available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.20 no.4 (december 2019) 14 – 47 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: raghad ali abbas , email: raghadaliabbas12233344445@gmail.com , name: hussain m. flayeh, email: hussmf200211@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. bioethanol (biofuel) production from low grade dates raghad ali abbas and hussain m. flayeh environmental engineering department, college of engineering, university of baghdad abstract bioethanol production from sugar fermentation is one of the most sustainable alternatives to substitute fossil fuel. production of bioethanol from low grade dates which are rich of sugars. an available sugar from a second grade dates (reduction sugar) was 90g/l in this study. sugar can be served as essential carbon sources for yeast growth in aerobic condition and can also be converted to bioethanol in anaerobic condition. the effect of various parameters on bioethanol production, fermentation time, ph-values, inoculum size and initial sugar concentration were varied in order to determine the optimal of bioethanol production. the highest bioethanol yield was 33g/l which was obtained with sugar concentration 90 g/l, inoculum size 1%, 52h time and ph-value 5. keywords: bioethanol, fermentation, saccharomycie cerevisiae, low grade iraqi dates received on 05/02/2019, accepted on 03/04/2019, published on 30/12/1029 https://doi.org/10.31699/ijcpe.2019.4.7 1introduction the planet is sink in energy problems due to development in different life sectors that lead to intensive consumption of the fossil fuels also the high prices of fossil fuels in all over the world. the world depends on nonrenewable energy sources for transport, heat and/or power generation. fossil fuels are currently the main energy source, providing an estimated 78.4% of the global final energy consumption. increased awareness of environmental problems like greenhouse gases and global warming seeks for alternative energy sources that are competitive to be more sustainable and economical [1]. biofuel is one of the sustainable fuel that can be produced from biodegradable part of products like cellulosic biomass, waste of chicken feathers, food and organic waste such as agricultural waste by carbon fixation biologically [2]. some other sources of biofuel production are waste cooking oil and plants that generate carbohydrates or fats which capable to be a source of biofuel [3]. algae is one of the most favorable sources of protein supplements, biofuel, and organic fertilizer owing to their advantages like capacity to use fresh, marine or wastewater, reduce greenhouse gas from the environment, non-competing with food yields, and non-requirement of fertile land low cost and large scale process for biofuel production from municipal and agricultural waste which are more afforded from research seekers [4]. in iraq, the best standard raw material for bioethanol production is date palm for two reasons; firstly the cost of production dates palm juices is usually less expensive than other sources, secondly juices of date palm fruits are purer than the other sources [5]. microorganisms like saccharomyces cerevisiae play an important role in one of the safest and most successful biological reactions in which biological reaction return the balance within the environmental system, in addition to converting the waste of date palm fruit to economic profit products [6]. fermentation is biological process in which sugars are converted to alcohol in an aerobic condition by the action of microorganisms [7]. yeast (saccharomycie cerevisiae) and zymomonas mobilis of bacteria are microorganisms capable of producing ethanol as a product by converting sugars into ethanol. the most common microorganism to produce bioethanol is saccharomyces cerevisiae, because it is already safer to produce and had accepted as nonpathogenic, this organism can be easily grown on simple and cheap media compared to cell cultivation to other microorganisms [8]. parameters had a huge effect on yeast cells broth such as ph, amount of oxygen, the amount and type of nutrients in broth, and temperature. 30 and 35°c was an optimum temperature for saccharomyces cerevisiae [9]. as the fermentation is anaerobic condition, no oxygen was supplied. by controlling the process conditions as well as possible for a specific process ethanol is the main product produced when saccharomyces cerevisiae fermented sugars. the “date strategy report” in iraq specified that 35.7% of the date crop (the low grade dates) are used for animal as a food source to the sheep herders and dairies and from the total production 14.3% is wasted [10]. low grade iraqi date is commonly used as animal food was selected from marketplace. carbon source, nitrogen source in addition to essential minerals and vitamins are nutrient requirements for the saccharomyces cerevisiae to generate energy and cellular growth which present in the composition of date extracts. https://doi.org/10.31699/ijcpe.2019.4.7 r. a. abbas and h. m. flayeh / iraqi journal of chemical and petroleum engineering 20,4 (2019) 12 14 24 ph, time, inoculum size and initial sugar concentrations were factors that affected the mechanism of ethanol production during the fermentation procedure. waste palm date fruit is recycled in this study to produce bioethanol by used saccharomyces cervisiae. evaluation of the influence of different conditions, such as fermentation time, ph-values, inoculum size, and initial sugar concentration on fermentation performance in order to determine the optimal bioethanol production 2experimental work 2.1. substrate preparation samples of date are weighted. date flash separated from date pits because high sugar content that is used in the preparation process of substrate. date flash is washed with distaled water twice and mixed with deionized water with ratio (2/5)(w/w sample to water)[11]. the extraction of sugar date is affected by the temperature of the water and time of extraction, as well as mixing of particle of the date flash. mixture of flash date is blended by using home blender to form suspension at 25 o c without heating [12]. fig. 1. the suspension of date flash after mixing in blender at 25 o c after soaking for 24 hrs suspension of date flash was filtrated through a piece of cloth to separate dissolved and non-dissolved particles in order to form date juice. date juice filtrated through filtered paper (what man cat no: 1441) to remove particles which were passed through the piece of cloth. solid suspension and fibers in date juice were removed by centrifugation at (8000 rpm) for 20 minutes in a centrifuge. the date juice passed through filter (mille pore 0.45mm) to remove impurities and prevent any microbial growth that effected on saccharomyces cereivisiae growth. 2.2. mineral salt media preparation (msm) this media equipped according to rahna [13], the preparations started with dissolving different chemical compounds showed in table 1 in one liter of deionized water at ph 5.0. msm was sterilized at 121˚c for 15 min by autoclave (hirayama/ japan). this media was used to activate saccharomyces cerivisiae to growth. table 1. chemical compounds used for preparations msm component weight (g/l) (nh4)2so4 1 yeast extract 1 k 2hpo 4 1 mgso4.7h 2 o 0.2 cacl 2.h 2 o 0.1 fecl 3 0.002 glucose 2 fig. 2. mineral salt media in magnetic stirrer and hot plat 2.3. effect of various parameters on ethanol production a. effect time on production of bio-ethanol time course was considered to be estimated for an optimum period time for ethanol production process to produce high concentration of ethanol and the substrate of date juice was prepared. 100 ml of the substrate for fermentation process was put in flask 300ml .after adding 1%(w/v) of yeast, the first one in aerobic condition for 24h incubator shaker 120 rpm at 30℃ at ph=5 the second step in anaerobic condition in the shaker 120 rpm at 30℃ for 28h. r. a. abbas and h. m. flayeh / iraqi journal of chemical and petroleum engineering 20,4 (2019) 12 14 24 b. effect of ph on production of bio-ethanol effect of ph on bio-ethanol production was studied. different substrates were prepared in different ph (4.5, 5, 5.5, 6, and 6.5) to study the effect of ph on biomass and bioethanol production by added few drops of hcl, 100 ml of substrate was prepared for fermentation process. date juice filtrated by passing it through filter (mille pore 0.45mm) and added (1)%(w/v)of yeast. after 24h of aerobic conditions incubator shaker 120 rpm at 30℃ to help saccharomyces cerivisiae to growth in the media then 24h in anaerobic condition to produce bioethanol in shaker 120 rpm at 30℃. c. effect inoculum size on bio-ethanol production different concentrations of inoculums include (0.25, 0.5, 1, 2, and 3) % was tested to estimate the best inoculums concentration for ethanol production during fermentation process and biomass growth. d. effect of initial sugar concentration on bio-ethanol production different concentration of sugar was investigated to study (0%, 25%, 50%, and 75%) from date juice. substrate was prepared in flask 300ml then 1% of yeast added to substrate at ph=5. the flask aerated for 24 hrs and 30℃ then 24hrs. of anaerobic condition in shaker 120 rpm at 30℃ to produced bioethanol. 2.4. estimation of residual sugar the residual sugar in fermentation broth filtrate is estimated by using suitable glucose oxidase kit, (croma test mr 4×250) by linear chemicals was used, date of production 2015. the calculations and preparations conducted to manufactures procedures, were : 1blank was prepared by adding 3 ml from reagent (r1) to number of remarked glasses tubes. the r1 reagent was mono reagent, consists of 100000 mol/l at ph 7.5 phosphate buffer, 10 ku/l < glucose oxidase 2 ku/l < peroxidase , 4-aminoantipyrine 500 mol/l, phenol 5000 mol/l . 2standard sample was prepared by adding 30 μl of glucose standard solution to 3ml reagent (r1). standard contains, glucose 1000 mg/l (5550 mol/l). 330 μl of each sample (supernatant) was added to 3ml of reagent (r1). each tube was mixed well and incubated for 10 minutes in room temperature or 5 minutes in incubator with temperature 37°c. the absorbance of samples was measured at 500nm spectrophotometer, then the reducing sugar concentration was calculated by the following equation: glucose concentration mg/dl = 𝑎𝑏𝑠𝑜𝑟𝑏𝑎𝑛𝑐𝑒 𝑟𝑒𝑎𝑑𝑖𝑛𝑔 𝑓𝑜𝑟 𝑠𝑎𝑚𝑝𝑙𝑒 𝑎𝑏𝑠𝑜𝑟𝑏𝑎𝑛𝑐𝑒 𝑟𝑒𝑎𝑑𝑖𝑛𝑔 𝑓𝑜𝑟 𝑠𝑡𝑎𝑛𝑑𝑎𝑟𝑑 ×c standard (1) 2.5. measurement of biomass to determine the biomass by drying weight at the end of incubation time, the substrate is centrifuged at 8000 rpm for 20 min. after weighting the filter paper then filtering the substrate and drying it in oven at 50 ℃ and reweighted. the difference of the initial and final weight of filter paper gave the amount of biomass and calculated by equation (2) : biomass (g/l) = (2) 2.6. determination of bioethanol concentration concentrations of bioethanol were determined by high performance liquid chromatography (hplc) according to the operating conditions below in the table (2). the column used in analyzing was jiods c18, usa (250×4.6 id) with mobile phase 10% and 90% acetonitrile with flow rate 1ml/min. column oven temperature at room temperature with uv (uv-visible spectrophotometer at 210 nm detector. jsr/ korea). operation condition are shown in the table.2. table 2. hplc operating condition condition range column temperature 80°c detector temperature 55°c flow rate 1.00ml/min injection volume 2µl mobile phase mark water run time 20min 3results and discussion 3.1. the effect of time on bio-ethanol production shorter fermentation time causes insufficient growth of microorganisms that finally causes incompetent fermentation. instead, longer fermentation time causes microbial growth toxicity effects due to the high ethanol concentration in the fermented broth [14]. the results of the fermentation in batch experiment are presented in the figure (3), which shows the kinetic profiles of the dates sugar and bioethanol resulting from the fermentation process, initial sugar concentration (46g/l) fermented by s.cerevisiae. after 28h of fermentation time (38g/l) consumption of sugar, the ethanol yields (30g/l). the optimum fermentation time for this production was (52h). this is conformity with the findings [14]. the sugar concentration decreased with time as showed in fig. 3. biomass increased with time during (24h) with time biomass decreased because concentration of the fermentation medium began to decrease with time in this study this similar to other study [4]. r. a. abbas and h. m. flayeh / iraqi journal of chemical and petroleum engineering 20,4 (2019) 12 14 22 fig. 3. effect of time on bioethanol production at sugar concentration (90g/l), inoculum size (1%) and ph-value (5) 3.2. effect of ph on bioethanol produuction in general, ph-values in fermentation memberane affect the absorbency of some important nutrients into the cell. the best ph range for s.cerevisiae used in fermentation for bioethanol production is (5) [15,16]. the results obtained in figure(4) shown below the different bioethanol production with different ph-value (4.5,5,5.5,6,6.5). the bioethanol production increases with the increase in ph –values and reaches a maximum production, for a phvalues equal to 5 (33g/l). these results were similier to other studies like [20].the bioethanol production decreased slightly for the phvalues higher than 5. these results are comparable to those described by [17]. fadel m. [18] was reported that high bioethanol production was obtained by using initial ph-values 5 to 6 , which was in agreement with the results of this study. media of date juice was prepared in a way to get an initial total sugars of (90g/l), 24h of earobic condition to activation the sacchromycieses cerivisiae at 30°c for 120 rpm. biomass growth and ethanol production and residual sugar were estimated to obtain the optimum values at ph 5 as shown in the figure (5). fig. 4. bioethanol results in different phvalue after (52hrs.) by using (1%) of inoculum size the biomass increased during (24hrs.) then decreased with time similar to explination in [7] as shown in the fig. 5. residual sugar concentration decreased with time due to converted it to bioethnol with time as showen below in the fig. 6. fig. 5. effect of ph on biomass at different ph-values during (52hrs.), initial sugar con.90g/l and inoculum size (1%) fig. 6. effect of ph-values on suar consumption during (52hrs.) at inial sugar con.(90g/l) andinoculum size (1%) 3.3. effect of inoculum size on bioethanol production five different inoculum size (0.5%,1%,2%,4%,6%) were tested to predicate the best additional of inoculum to determine the effect of inoculum size on kinetic parameters of ethanol fermentation from low grade dates. the maximum bioethanol yield (30g/l) and maximum biomass (15g/l) were found with 1% inoculum size which product (30g/l) ethanol. fermentation process began and continued 52h at 30°c and 120rpm. optimum ethanol concentration yield at inoculum 1% was(30g/l) other inoculum 0.5% ethanol yield (20g/l), 2% inoculum size ethanol yield(23g/l), 4% inoculum ethanol yield (15.3 g/l), and 6%inoculum ethanol yield (12.4g/l) as shown in fig. 7 r. a. abbas and h. m. flayeh / iraqi journal of chemical and petroleum engineering 20,4 (2019) 12 14 24 fig. 7. results of bioethanol, biomass and residual sugar after (52 hrs.) at different inoculum size, ph-value 5 and initial sugar con (90 g/l) ethanol yield decrease with increased inoculum size due to increase biomass which required more substrates in media with time sugar concentration decreased. the results in this study similar to other study [19] sugar conversion was continuing simultaneously during the fermentation, and after 52h of fermentation, sugar was completely consumed in both cases as shown in fig. 8 fig. 8. effect of inoculum size on sugar consumption during (52hrs.), initial sugar con.(90 g/l) and (1%) inoculum size after consumption of sugar, both production of ethanol and growth of biomass slowed as shown in the fig. 9 fig. 9. effect of inoculum size on biomass growth during (52hrs) 3.4. effect sugar concentration on bioethanol production four different sugar concentrations is tested to predict the best sugar concentration in fermentation process. these experiments are prepared in four different concentration by dilution the date juice with distilled water according these ratio (0%,25%,50%,75%) to determine the effect of sugar concentration of ethanol fermentation from low grade dates figure (10) shows the ethanol production(g/l), fermentation process began and continued 52 h at 30°c and 120rpm. optimum ethanol concentration yield was at 52h. the results are showed that ethanol yield at initial sugar concentration (100%) were (45g/l), at (75%) initial sugar concentration ethanol yield (27g/l), (50%) initial sugar concentration ethanol yield (9.8) and (25%) initial sugar concentration ethanol yield (2.4g/l). fig. 10. effect of initial concentration of sugar on bioethanol production fig. 11. consumption sugar during fermentation process during 52hrs sugar profiles as well as the ethanol produced during fermentation were shown in fig (10). the 100% initial sugar concentrations date extract was completely fermented in 28h producing 45g/l ethanol. on the other hand, for initial sugar concentration of date extract of (75, 50 and 25) % resulting in final ethanol concentrations of 27, 9.8 and 2.4 g/l. lower ethanol yield was obtained for 25% concentration compared to the other two concentrations. it is clear that from fig (10) higher ethanol yield during fermentation is obtained with date r. a. abbas and h. m. flayeh / iraqi journal of chemical and petroleum engineering 20,4 (2019) 12 14 24 extract concentration of 100%. this result similar to other study [1]. when compared to biomass growth between four different concentration biomassincreased with high level of concentration as shown in the figure (12). when the fermentation process continued and sugar consumption was continuing simultaneously during the fermentation, and after 52 h, sugar was completely consumed as shown in the figure (11). after consumption of sugar , both the production of ethanol and growth of biomass slowed as shown in the figure (10) as expected these results similar to [20]. fig. 12. the biomass in different sugar concentration during fermentation process 4conclusion low-grade-dates are rich of sugars which can be converted to ethanol and can also attend as essential carbon sources for yeast growth. other nutrients, minerals and vitamins are also existent within date's constituents which improve the fermentation. the highest bioethanol yield was 33g/l which obtained with sugar concentration 90 g/l, inoculum size 1%, 52h time and ph-value 5. from initial sugar concentration were most significant factors affecting ethanol production. the batch experiment shows that the bioethanol continues produced during 28h from anaerobic condition, and high bioethanol yield at ph 5 by added 1% from the inoculum size of yeast with initial sugar concentration 90g/l after preparation process. references [1] sulieman, a. k., gaily, m. h., zeinelabdeen, m. a., putra, m. d., & abasaeed, a. e. (2013). production of bioethanol fuel from low-grade-date extract. international journal of chemical engineering and applications, 4(3), 140. [2] zainab, b., & fakhra, a. (2014). production of ethanol by fermentation process by using yeast saccharomyces cerevisae. int. res. j. environ. sci, 3, 24-32 [3] kaygusuz, k. (2012). energy for sustainable development: a case of developing countries. renewable and sustainable energy reviews, 16(2), 1116-1126 [4] taouda, h., chabir, r., aarab, l., miyah, y., & errachich, f. (2017). biomass and bioethanol production from date extract. j. mater. environ. sci, 8(9). [5] ghanim, a. n. (2013). bioethanol production from iraqi date palm resources. j. babylon univ. eng. sci, 21(1), 248-239. [6] meintjes, m. m. (2011). fermentation coupled with pervaporation: a kinetic study (doctoral dissertation, north-west university, potchefstroom campus. [7] skovgaard, niels. "industrial microbiology: an introduction-michael j. waites, neil l. morgan, john s. rockey, gary higton (eds.); blackwell science, oxford, uk, 2001; soft cover, xi+ 288 pp.;@ $29.95; isbn 0-632-05307-0; http://www. blackwellpublishing. com." international journal of food microbiology 3.77 (2002): 243-244. [8] presečki, a. v., & vasić-rački, đ. (2005). modelling of the alcohol dehydrogenase production in baker's yeast. process biochemistry, 40(8), 2781-2791. [9] taherzadeh, m.j. & karimi, k. 2008. bioethanol: market and production processes. (in nag, a., ed. biofuels refining and performance. new york: mcgraw hill. p. 69-106.) [10] barreveld, w.h. date palm products; food and agriculture organization of the united nations: rome, italy, 1993. [11] matloob, m. h., & hamza, m. b. (2013). vinegar production from low cost iraqi dates. journal of kerbala university, 11(3), 29-35. [12] myhara, r.m.; karkalas, j.; taylor, m.s. the composition of maturing omani dates. j. sci. food agric. 1999, 79, 1345–1350. [13] rahna, k., rathnan, and ambili, m. (2011). cellulase enzyme production by streptomyces sp using fruit waste as substrate. [14] gaily, m. h., sulieman, a. k., zeinelabdeen, m. a., al-zahrani, s. m., atiyeh, h. k., & abasaeed, a. e. (2012). the effects of activation time on the production of fructose and bioethanol from date extract. african journal of biotechnology, 11(33), 8212-8217. [15] lin, y. & tanaka, s. 2006. ethanol fermentation from biomass resources: current state and prospects. applied microbiology biotechnology, 69: 627-642. [16] zhang, k. c. (1995). alcohol and distilling wine craft. china light industry press, beijing, 246-7. [17] thenmozhi, r., & victoria, j. (2013). optimization and improvement of ethanol production by the incorporation of organic wastes. pelagia research library, 4(5), 119-23. [18] fadel, m. (2000). alcohol production from potato industry starchy waste. egyptian journal of microbiology (egypt). [19] izmirlioglu, g., & demirci, a. (2012). ethanol production from waste potato mash by using saccharomyces cerevisiae. applied sciences, 2(4), 738753. [20] najim, a. a., & mohammed, a. a. (2018). biosorption of methylene blue from aqueous solution using mixed algae. iraqi journal of chemical and petroleum engineering, 19(4), 1-11. http://www.ijcea.org/papers/280-i025.pdf http://www.ijcea.org/papers/280-i025.pdf http://www.ijcea.org/papers/280-i025.pdf http://www.ijcea.org/papers/280-i025.pdf http://www.ijcea.org/papers/280-i025.pdf https://s3.amazonaws.com/academia.edu.documents/45676260/ethanoolfromtissuepaper-4.isca-irjevs-2014-106.pdf?response-content-disposition=inline%3b%20filename%3dproduction_of_ethanol_by_fermentation_pr.pdf&x-amz-algorithm=aws4-hmac-sha256&x-amz-credential=akiaiwowyygz2y53ul3a%2f20191228%2fus-east-1%2fs3%2faws4_request&x-amz-date=20191228t235136z&x-amz-expires=3600&x-amz-signedheaders=host&x-amz-signature=97f25bf7e98632439747e763e9e228e115a6483e72273f5c189ef6d7c3ca2d64 https://s3.amazonaws.com/academia.edu.documents/45676260/ethanoolfromtissuepaper-4.isca-irjevs-2014-106.pdf?response-content-disposition=inline%3b%20filename%3dproduction_of_ethanol_by_fermentation_pr.pdf&x-amz-algorithm=aws4-hmac-sha256&x-amz-credential=akiaiwowyygz2y53ul3a%2f20191228%2fus-east-1%2fs3%2faws4_request&x-amz-date=20191228t235136z&x-amz-expires=3600&x-amz-signedheaders=host&x-amz-signature=97f25bf7e98632439747e763e9e228e115a6483e72273f5c189ef6d7c3ca2d64 https://s3.amazonaws.com/academia.edu.documents/45676260/ethanoolfromtissuepaper-4.isca-irjevs-2014-106.pdf?response-content-disposition=inline%3b%20filename%3dproduction_of_ethanol_by_fermentation_pr.pdf&x-amz-algorithm=aws4-hmac-sha256&x-amz-credential=akiaiwowyygz2y53ul3a%2f20191228%2fus-east-1%2fs3%2faws4_request&x-amz-date=20191228t235136z&x-amz-expires=3600&x-amz-signedheaders=host&x-amz-signature=97f25bf7e98632439747e763e9e228e115a6483e72273f5c189ef6d7c3ca2d64 https://www.sciencedirect.com/science/article/abs/pii/s1364032111005491 https://www.sciencedirect.com/science/article/abs/pii/s1364032111005491 https://www.sciencedirect.com/science/article/abs/pii/s1364032111005491 https://www.researchgate.net/profile/lotfi_aarab2/publication/317345959_biomass_and_bio-ethanol_production_from_date_extract/links/593aa84ca6fdcc17a98a561f/biomass-and-bio-ethanol-production-from-date-extract.pdf https://www.researchgate.net/profile/lotfi_aarab2/publication/317345959_biomass_and_bio-ethanol_production_from_date_extract/links/593aa84ca6fdcc17a98a561f/biomass-and-bio-ethanol-production-from-date-extract.pdf https://www.researchgate.net/profile/lotfi_aarab2/publication/317345959_biomass_and_bio-ethanol_production_from_date_extract/links/593aa84ca6fdcc17a98a561f/biomass-and-bio-ethanol-production-from-date-extract.pdf http://www.uobjournal.com/papers/uobj_paper_2014_4951871.pdf http://www.uobjournal.com/papers/uobj_paper_2014_4951871.pdf http://www.uobjournal.com/papers/uobj_paper_2014_4951871.pdf https://repository.nwu.ac.za/handle/10394/7283 https://repository.nwu.ac.za/handle/10394/7283 https://repository.nwu.ac.za/handle/10394/7283 skovgaard,%20niels.%20%22industrial%20microbiology:%20an%20introduction-michael%20j.%20waites,%20neil%20l.%20morgan,%20john%20s.%20rockey,%20gary%20higton%20(eds.);%20blackwell%20science,%20oxford,%20uk,%202001;%20soft%20cover,%20xi+%20288%20pp.;@%20$29.95;%20isbn%200-632-05307-0;%20http:/www.%20blackwellpublishing.%20com.%22 international%20journal%20of%20food%20microbiology 3.77%20(2002):%20243-244. skovgaard,%20niels.%20%22industrial%20microbiology:%20an%20introduction-michael%20j.%20waites,%20neil%20l.%20morgan,%20john%20s.%20rockey,%20gary%20higton%20(eds.);%20blackwell%20science,%20oxford,%20uk,%202001;%20soft%20cover,%20xi+%20288%20pp.;@%20$29.95;%20isbn%200-632-05307-0;%20http:/www.%20blackwellpublishing.%20com.%22 international%20journal%20of%20food%20microbiology 3.77%20(2002):%20243-244. skovgaard,%20niels.%20%22industrial%20microbiology:%20an%20introduction-michael%20j.%20waites,%20neil%20l.%20morgan,%20john%20s.%20rockey,%20gary%20higton%20(eds.);%20blackwell%20science,%20oxford,%20uk,%202001;%20soft%20cover,%20xi+%20288%20pp.;@%20$29.95;%20isbn%200-632-05307-0;%20http:/www.%20blackwellpublishing.%20com.%22 international%20journal%20of%20food%20microbiology 3.77%20(2002):%20243-244. skovgaard,%20niels.%20%22industrial%20microbiology:%20an%20introduction-michael%20j.%20waites,%20neil%20l.%20morgan,%20john%20s.%20rockey,%20gary%20higton%20(eds.);%20blackwell%20science,%20oxford,%20uk,%202001;%20soft%20cover,%20xi+%20288%20pp.;@%20$29.95;%20isbn%200-632-05307-0;%20http:/www.%20blackwellpublishing.%20com.%22 international%20journal%20of%20food%20microbiology 3.77%20(2002):%20243-244. skovgaard,%20niels.%20%22industrial%20microbiology:%20an%20introduction-michael%20j.%20waites,%20neil%20l.%20morgan,%20john%20s.%20rockey,%20gary%20higton%20(eds.);%20blackwell%20science,%20oxford,%20uk,%202001;%20soft%20cover,%20xi+%20288%20pp.;@%20$29.95;%20isbn%200-632-05307-0;%20http:/www.%20blackwellpublishing.%20com.%22 international%20journal%20of%20food%20microbiology 3.77%20(2002):%20243-244. skovgaard,%20niels.%20%22industrial%20microbiology:%20an%20introduction-michael%20j.%20waites,%20neil%20l.%20morgan,%20john%20s.%20rockey,%20gary%20higton%20(eds.);%20blackwell%20science,%20oxford,%20uk,%202001;%20soft%20cover,%20xi+%20288%20pp.;@%20$29.95;%20isbn%200-632-05307-0;%20http:/www.%20blackwellpublishing.%20com.%22 international%20journal%20of%20food%20microbiology 3.77%20(2002):%20243-244. skovgaard,%20niels.%20%22industrial%20microbiology:%20an%20introduction-michael%20j.%20waites,%20neil%20l.%20morgan,%20john%20s.%20rockey,%20gary%20higton%20(eds.);%20blackwell%20science,%20oxford,%20uk,%202001;%20soft%20cover,%20xi+%20288%20pp.;@%20$29.95;%20isbn%200-632-05307-0;%20http:/www.%20blackwellpublishing.%20com.%22 international%20journal%20of%20food%20microbiology 3.77%20(2002):%20243-244. https://www.sciencedirect.com/science/article/pii/s0032959205000221 https://www.sciencedirect.com/science/article/pii/s0032959205000221 https://www.sciencedirect.com/science/article/pii/s0032959205000221 https://s3.amazonaws.com/academia.edu.documents/30987768/nag_biofuels_refining_and_performance_0071489703.pdf?response-content-disposition=inline%3b%20filename%3dbioethanol_market_and_production_process.pdf&x-amz-algorithm=aws4-hmac-sha256&x-amz-credential=akiaiwowyygz2y53ul3a%2f20191228%2fus-east-1%2fs3%2faws4_request&x-amz-date=20191228t235851z&x-amz-expires=3600&x-amz-signedheaders=host&x-amz-signature=4d65ab553040caadf693663a8bd956f97b5927a97801d47a3b1308f0fcdf4986#page=86 https://s3.amazonaws.com/academia.edu.documents/30987768/nag_biofuels_refining_and_performance_0071489703.pdf?response-content-disposition=inline%3b%20filename%3dbioethanol_market_and_production_process.pdf&x-amz-algorithm=aws4-hmac-sha256&x-amz-credential=akiaiwowyygz2y53ul3a%2f20191228%2fus-east-1%2fs3%2faws4_request&x-amz-date=20191228t235851z&x-amz-expires=3600&x-amz-signedheaders=host&x-amz-signature=4d65ab553040caadf693663a8bd956f97b5927a97801d47a3b1308f0fcdf4986#page=86 https://s3.amazonaws.com/academia.edu.documents/30987768/nag_biofuels_refining_and_performance_0071489703.pdf?response-content-disposition=inline%3b%20filename%3dbioethanol_market_and_production_process.pdf&x-amz-algorithm=aws4-hmac-sha256&x-amz-credential=akiaiwowyygz2y53ul3a%2f20191228%2fus-east-1%2fs3%2faws4_request&x-amz-date=20191228t235851z&x-amz-expires=3600&x-amz-signedheaders=host&x-amz-signature=4d65ab553040caadf693663a8bd956f97b5927a97801d47a3b1308f0fcdf4986#page=86 https://s3.amazonaws.com/academia.edu.documents/30987768/nag_biofuels_refining_and_performance_0071489703.pdf?response-content-disposition=inline%3b%20filename%3dbioethanol_market_and_production_process.pdf&x-amz-algorithm=aws4-hmac-sha256&x-amz-credential=akiaiwowyygz2y53ul3a%2f20191228%2fus-east-1%2fs3%2faws4_request&x-amz-date=20191228t235851z&x-amz-expires=3600&x-amz-signedheaders=host&x-amz-signature=4d65ab553040caadf693663a8bd956f97b5927a97801d47a3b1308f0fcdf4986#page=86 https://agritrop.cirad.fr/582536/1/id582536.pdf https://agritrop.cirad.fr/582536/1/id582536.pdf https://agritrop.cirad.fr/582536/1/id582536.pdf https://www.iasj.net/iasj?func=article&aid=78972 https://www.iasj.net/iasj?func=article&aid=78972 https://www.iasj.net/iasj?func=article&aid=78972 https://onlinelibrary.wiley.com/doi/abs/10.1002/(sici)1097-0010(199908)79:11%3c1345::aid-jsfa366%3e3.0.co;2-v https://onlinelibrary.wiley.com/doi/abs/10.1002/(sici)1097-0010(199908)79:11%3c1345::aid-jsfa366%3e3.0.co;2-v https://onlinelibrary.wiley.com/doi/abs/10.1002/(sici)1097-0010(199908)79:11%3c1345::aid-jsfa366%3e3.0.co;2-v https://www.cabdirect.org/cabdirect/abstract/20123068172 https://www.cabdirect.org/cabdirect/abstract/20123068172 https://www.cabdirect.org/cabdirect/abstract/20123068172 https://www.ajol.info/index.php/ajb/article/view/127619 https://www.ajol.info/index.php/ajb/article/view/127619 https://www.ajol.info/index.php/ajb/article/view/127619 https://www.ajol.info/index.php/ajb/article/view/127619 https://www.ajol.info/index.php/ajb/article/view/127619 https://link.springer.com/article/10.1007/s00253-005-0229-x https://link.springer.com/article/10.1007/s00253-005-0229-x https://link.springer.com/article/10.1007/s00253-005-0229-x https://link.springer.com/article/10.1007/s00253-005-0229-x https://s3.amazonaws.com/academia.edu.documents/37880967/j.v__thenmo.pdf?response-content-disposition=inline%3b%20filename%3doptimization_and_improvement_of_ethanol.pdf&x-amz-algorithm=aws4-hmac-sha256&x-amz-credential=akiaiwowyygz2y53ul3a%2f20191229%2fus-east-1%2fs3%2faws4_request&x-amz-date=20191229t000535z&x-amz-expires=3600&x-amz-signedheaders=host&x-amz-signature=82834dcaa83a39dca2e6fff506cf8dfbd159b644e28a20aedc969a1fbf2aa026 https://s3.amazonaws.com/academia.edu.documents/37880967/j.v__thenmo.pdf?response-content-disposition=inline%3b%20filename%3doptimization_and_improvement_of_ethanol.pdf&x-amz-algorithm=aws4-hmac-sha256&x-amz-credential=akiaiwowyygz2y53ul3a%2f20191229%2fus-east-1%2fs3%2faws4_request&x-amz-date=20191229t000535z&x-amz-expires=3600&x-amz-signedheaders=host&x-amz-signature=82834dcaa83a39dca2e6fff506cf8dfbd159b644e28a20aedc969a1fbf2aa026 https://s3.amazonaws.com/academia.edu.documents/37880967/j.v__thenmo.pdf?response-content-disposition=inline%3b%20filename%3doptimization_and_improvement_of_ethanol.pdf&x-amz-algorithm=aws4-hmac-sha256&x-amz-credential=akiaiwowyygz2y53ul3a%2f20191229%2fus-east-1%2fs3%2faws4_request&x-amz-date=20191229t000535z&x-amz-expires=3600&x-amz-signedheaders=host&x-amz-signature=82834dcaa83a39dca2e6fff506cf8dfbd159b644e28a20aedc969a1fbf2aa026 https://s3.amazonaws.com/academia.edu.documents/37880967/j.v__thenmo.pdf?response-content-disposition=inline%3b%20filename%3doptimization_and_improvement_of_ethanol.pdf&x-amz-algorithm=aws4-hmac-sha256&x-amz-credential=akiaiwowyygz2y53ul3a%2f20191229%2fus-east-1%2fs3%2faws4_request&x-amz-date=20191229t000535z&x-amz-expires=3600&x-amz-signedheaders=host&x-amz-signature=82834dcaa83a39dca2e6fff506cf8dfbd159b644e28a20aedc969a1fbf2aa026 https://vlibrary.emro.who.int/imemr/alcoholproduction-from-potato-industry-starchy-waste/ https://vlibrary.emro.who.int/imemr/alcoholproduction-from-potato-industry-starchy-waste/ https://vlibrary.emro.who.int/imemr/alcoholproduction-from-potato-industry-starchy-waste/ https://www.mdpi.com/2076-3417/2/4/738 https://www.mdpi.com/2076-3417/2/4/738 https://www.mdpi.com/2076-3417/2/4/738 https://www.mdpi.com/2076-3417/2/4/738 https://doi.org/10.31699/ijcpe.2018.4.1 https://doi.org/10.31699/ijcpe.2018.4.1 https://doi.org/10.31699/ijcpe.2018.4.1 https://doi.org/10.31699/ijcpe.2018.4.1 r. a. abbas and h. m. flayeh / iraqi journal of chemical and petroleum engineering 20,4 (2019) 12 14 24 انتاج االيثانول الحيوي من التمور رديئة النوعية رغد علي وحسين فليح جامعة بغداد-كمية الهندسة-البيئةقسم هندسة الخالصة في هذا .انتاج االيثانول الحيوي من تخمر السكر واحدة من البدائل المستدامة الحالية عن الوقود االحفوري العمل كان انتاج االيثانول الحيوي من تمور رديئة نوعية غنية بالسكريات حيث يتراوح السكر في التمور رديئة لتروالذي يعتبر مصدر اساسي لنموالخمائر في الظروف الهوائية ليتم تحويل السكر الى \غم09بمقدار النوعية هناك العديد من المتغيرات التي تؤثر عمى انتاج االيثانول منها زمن .االيثانول الحيوي في الظروف االهوائية تغايرت هذه العوامل وذلك لتحديد القيمة التخمر,قيمة االس الهيدروجيني, حجم المقاح, وتركيز السكر االبتدائي. المثمى من كل متغير لمحصول عمى اعمى انتاج لاليثانول الحيوي. ان اعمى انتاج لاليثانول الحيوي هو ساعة,حيث كانت قيمة االس 25%,وزمن 1لتر من تركيز السكر االبتدائي وحجم لقاح \غم09لتر عند \غم33 . 2الهيدروجيني .النوعية , ساكرومايسس سيرفيسيا: االيثانول الحيوي , تخمر , تمور رديئة الكممات الدالة removal of dissolved cadmium ions from contaminated wastewater using raw scrap zero-valent iron and zero valent aluminum as locally available and inexpensive sorbent wastes available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.19 no.3 (september 2018) 33 –40 issn: 1997-4884 zahraa_z91@yahoo.com amel habeeb assi, email: corresponding authors: ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. potato starch for enhancing the properties of the drilling fluids amel habeeb assi university of baghdad / college of engineering abstract different additives are used in drilling fluids when the demanded properties cannot be gotten with clays. drilling muds needs several additives and materials to give good characteristics. there are local alternatives more suitable for enhancing the rheology and filtration of drilling fluids. an experimental work had been conducted to assess the suitability of using potato starch to enhance rheological properties and filtration in drilling mud. this study investigated the potato starch as a viscosifier and fluid losses agent in drilling fluid. results from this study proved that rheological properties of potato starch mud increased when ph of drilling fluid is increased. potato starch could be used to enhance gel strength at low ph (approximately 8.6) and viscosifir at high ph mud (approximately 10.8). the experimental work show that the optimum naoh concentration was between (2-6) lb./bbl and if more than that concentration was used, the relation between ph and plastic viscosity would be inversed. comparative analysis of mud properties obtained from the potato starch and starch at low ph showed good rheological properties of the starch than for potato starch, while at high ph, both of them nearly showed good rheological properties. in conclusion, potato starch reduced filtration rate of fluid and improved the characteristics and consistency of mud cake as a primary function and showed an effect on the fluid rheology as a second function. keywords: starch, mud, filtration, rheology,potato starch. received on 08/04/2018, accepted on 11/07/2018, published on 30l09l2018 https://www.doi.org/10.31699/ijcpe.2018.3.4 1introduction a few years ago, used fluid was dumped in an open pit, polluting the natural environment and towns. really, this is no longer acceptable, and the drilling fluid must be disposed of in a manner where there is no pollution of the environment or towns. chemicals used in drilling mud may be polluting the environment as well, generating a wide of environmental problems. natural additives or native drilled solid are incorporated into the drilling fluid for viscosity, weight, and fluid losses control. they are often used with bentonite to enhance stability and fluid losses control ‎[1]. the drilling mud additives are responsible of enhancing optimizing and drilling efficiency and stability. keeping the proper viscosity and ph is very important step during the drilling process ‎[2]. in oil and gas processes, sodium hydroxide is an important material to maintain the integrity of water – based drilling mud. in oil well drilling naoh neutralizes gasses in rock formations, increases the viscosity of drilling mud, and is a good source of hydroxyl ions which leads to control ph. that increase in viscosity would prevent heavy materials from settling down in bore hole ‎[3]. various materials, chemicals and polymers are used in mud formulation to convene different practical mud requirements such as density, rheology and fluid losses control. one of such starch materials, starch (polymers) used for fluid loss control or as viscosifier, forms the basis of many studies ‎[4]. several corn based starch additives using local resources to study their suitability to use as drilling fluid additives have been developed ‎[5]. starch was considered as the first of the organic polymer which was used in substantial quantities in drilling mud. beginning in 1939 with salt water drilling fluid in west texas,'09 starch was used for controlling of filtration spread rapid rather than the other areas and applications wherever drilling fluid problems related to filtration were experienced‎[6]. the use of starch typically causes temperature stability at (225 ◦ f), a minimal increase in viscosity while effectively controlling fluid loss ‎[7]. experimental results indicate that some of newly developed starch products have similar or better filtration control properties than the filtration control properties of the widely used imported starch ‎[8]. thus, it is imperative to source locally available drilling fluid materials and evaluates their various characteristic, then determining fluid that can be used in drilling process. this study tends to investigate the determination of drilling fluid used as locally sourced material and in turn reduce the overdependence of some imported very expensive viscosifires. https://www.doi.org/10.31699/ijcpe.2018.3.4 a.h.assi./ iraqi journal of chemical and petroleum engineering91,3 (2018) 33-40 43 2experimental work 2.1. materials a. potato starch a potato starch is a substance which extracted from potatoes. a cell of root tubers of potato plant contains starch grains. to get the starch, the potatoes are crushed and the starch grain is released from the destroyed cells. starch is then washed out and after that dried to powder to use it ‎[9]. fig. 1 illustrates molecular structure of the potato starch. fig. 1. molecular structure of potato starch [6]. b. sodium hydroxide naoh the used name is caustic soda, its color is white; deliquescent; beads, pellets, flakes, very strong irritant to tissues. this material is used in water base muds for increasing ph; to solubilize lignite, lignosulghonate and tannin substances; to prevent corrosion, on the other hands to neutralize the hydrogen sulfide. caustic soda is experimentally added in concentration between 0.2-4 lb. /bbl. naoh is hazardous substance to handle because it is so caustic and generate off heat when dissolved in water. caustic soda should be added carefully and slowly. the amount that required increasing the ph range depends upon the type and concentration of drilling mud components ‎[6] the used sodium hydroxide was purchased from india. c. starch starch purchased from china is considered as a natural polymer which is primarily used for drilling purposes in brine fluids at relatively low temperature. starch is considered as one of a few materials unaffected by water salinity. the thermal degradation of starch begins at about 180°f and increases to be a prohibitive rate at a temperature of 250°f. the starch should be used in concentrations between of 2 to 6 lb. /bbl. because of its viscosity building ability; it is always used as a good source for regulating both viscosity and fluid-loss. starch is subjected to bacterial degradation and should be used with a preservative saturated salt fluid or at ph value equal to 11.5, and in fresh water where the chloride concentration is below 10,000 ppm ‎[10], ‎[11]. fig. 2 shows the molecular structure of starch. the used starch is manufactured in india. fig. 2. molecular structure of starch [6] 2.2. devices a. ph meter the control on drilling mud properties is dependent on the ph value. in other words, the detection and treatment of contaminants like cements during cementation and the soluble carbonates. ph also affects the solubility of a wide thinners types and divalent metal ions like calcium and magnesium, and influences the dispersion and flocculation of the clays types. ph meter( model 603 se) manufacturing in america is an electric device, consists of utilizing glass electrodes for measuring the potential difference which indicated directly as digital signal of ph of the drilling fluid. the ph meter is considered as the most accurate device for measuring ph of drilling muds ‎[6],as shown in fig. 3. fig. 3. ph meter b. mud balance density is used for controlling the hydrostatic pressure. mud density is measured by using mud balance. the mud balance is always calibrated with fresh water and it must give the reading of 1 gm. /cc. mud density test is conducted by using the mud balance tools. the mud balance consists of base and a balance arm with cup, lid, knife edge, rider, level glass, and counterweight. the cup is attached to one end of the balance arm and the counterweight is at the other end of the mud balance ‎[6]. the mud balance was manufactured by fann (model 140) manufacturing in america,as shown in fig. 4. fig. 4. mud balance a.h.assi./ iraqi journal of chemical and petroleum engineering91,3 (2018) 33-40 43 c. viscometer the rheological property is measured by using viscometer 8 speed (model 800) manufacturing in america. this device is commonly used for indicating solids buildup, flocculation or deflocculation of drilling fluid, and it helps for calculating the hydraulics of drilling muds ‎[12], as shown in fig. 5. fig. 5. viscometer d. the dead weight and hydraulic filter press is one of series 300 filter press equipped with a deadweight hydraulic tool ‎[6] as shown in fig. 6. fig. 6. the dead weight and hydraulic filter press 2.3. method this study involves two major experimental work, namely the preparation of the used drilling raw material "potato starch "and the rheological and filtration tests of the drilling muds. a. preparation of drilling raw material "potato starch" the procedure of preparing potato starch: 1potatoes were washed by water to clean them from muds and other things. 2potato were cut in to small pieces and put in the mixer with amount of fresh water 3a piece of clean cloth was used as a filtration paper, and then the potatoes were put and squeezed it in a bowl. 4after the potato starch has been squeezed, wait 40 min to make starch settle in the bottom of the bowl. 5potato starch was dried carefully by using a dryer (model syh-1307) which was manufactured in india to prevent any loss with air because of the fine particles of potato starch. after following the above steps, the result is as shown in fig. 7. fig. 7. the potato starch preparation 3results and discussion 3.1. the rheological and filtration tests of the drilling muds a. potato starch effect ln bentonite mud the compositions of drilling fluid samples were prepared in standard 350 ml laboratory barrel. in other words, each 1 gm. of material was added to 350 ml. of fluid and this was equivalent to add 1 pound of material to 1 barrel of fluid. this mixture consists of 350ml water, 22.5gm red bentonite, and 1, 2, 3 gm. of potato starch and then we add naoh to show the effect of ph value on the potato starch as shown in table 1 and table 2. table 1. potato starch mud properties φ shear rate blank mix potato starch 1gm potato starch 2gm potato starch 3gm rpm sec -1 lb./100ft 2 lb./100ft 2 lb./100ft 2 lb./100ft 2 600 1021.8 28 30 31 38 300 510.9 23 24 25 31 200 340.6 21 22 25 30 100 170.3 20 20 23 28 60 102.18 17 19 22 28 30 51.09 16 18 22 27 6 10.218 14 18 22 27 3 5.109 12 18 22 27 pv 5 6 6 7 yp 18 18 19 24 ph 8.6 8.64 8.67 8.67 ρ (gm./cc) 1.05 1.05 1.051 1.052 7.5min filter size cc 12 11 10 10 mud cake 2mm 1.5mm 1.5mm 1.35mm gel 10 sec 13 18 21 23 gel 10 min 16 23 26 29 a.h.assi./ iraqi journal of chemical and petroleum engineering91,3 (2018) 33-40 43 table 2. potato starch mud properties with 4 gm. naoh φ shearrate potato starch 1gm +4gm naoh potato starch 2gm +4gm naoh potato starch 3gm +4gm naoh rpm sec -1 lb./100ft 2 lb./100ft 2 lb./100ft 2 600 1021.8 54 74 81 300 510.9 44 61 66 200 340.6 40 56 59 100 170.3 37 50 50 60 102.18 34 47 49 30 51.09 27 44 44 6 10.218 17 38 41 3 5.109 11 18 21 pv 10 13 15 yp 34 48 51 ph 10.82 10.82 10.85 ρ (gm/cc) 1.06 1.061 1.063 7.5min filter size cc 8.75 6.9 6 mud cake 1.25 mm 1.25mm 1mm gel 10 sec 18 16 15 gel 10 min 16 17 18.5 b. the effect o adding potato starch on density of drilling fluid as shown in table 1 there is no significant effect of adding potato starch on density of drilling fluid because of the low specific gravity of potato starch. c. the effect of adding potato starch on gel strength of drilling fluid the gel strength is a measure of the thixotropic behavior of mud. thixotropy is the ability of the mud to form a gel structure when it is at rest and then it becomes fluid again once agitated. the gel strength is a measure of the stress required to break a gel structure under static conditions. it is also a measure of the same particle-to-particle forces that is determined by the yield point except that the gel strength is measured under static conditions and the yield point is measured under dynamic conditions. potato starch can be used to enhance gel strength at low ph, while after adding naoh the gel structure build up slowly not like that in the sample without naoh .the reason behind that is after adding naoh some bubbles or foam has been created and that will lead to weaken the ability of drilling fluid to form gel structure. as shown in fig. 8. d. the effect of adding potato starch on plastic viscosity of drilling fluid before adding naoh, the effect of potato starch on plastic viscosity was small .in contrast, after adding naoh, the effect of potato starch on plastic viscosity was significant as shown in fig. 9. in other words, the potato starch affected the drilling fluid properties at high ph . e. the effect of adding potato starch on yield point of drilling fluid the value of yield point is low before adding naoh, whereas the value of yield point is improved after adding naoh,as shown in fig. 10. the reason behind that is the increase in the yield point is dependent on the type of solids present and their respective surface charges, the concentration of these solids, and the type and concentration of other ions or salts that maybe present. f. the effect of adding potato starch on filtration potato starch control on filtration by viscosifying the water phase to restrict fluid flow through the filter cake is by hydrating, swelling and plugging pores in the filter cake. in other word, it builds viscosity in order to control fluid loss. fig. 11 and fig. 12 clarify that adding potato starch led to good filtration control. fig. 8. the effect of potato starch on 10 min gel strength. fig. 9. the effect of potato starch on plastic viscosity. fig. 10. the effect of adding naoh to the potato starch on the value of yp a.h.assi./ iraqi journal of chemical and petroleum engineering91,3 (2018) 33-40 43 fig. 11. the effect of potato starch on mud cake thickness fig. 12. the effect of potato starch on mud cake filters size. 3.2 comparision between the potato starch and starch the potato starch contains typical large oval spherical granules; its size ranges between 5 and 100 mm. potato starch has very refined starch, containing minimal protein or fat. this gives the powder a very clear white color, and the cooked starch has typical characteristics of the neutral taste, good clarity, high binding strength, and the minimal tendency to make foaming. thomas had been developed method, based on the reaction rate kinetics, to determine the rate of decomposition at various values of temperatures. by this means he proved that the temperature of decomposition of the starch was till about 225 °f (107°c). in other words, he founded that the thermal stability of starch is about 225 °f (107°c) ‎[13]. from the other hand the thermal stability of potato starch is 250°f ‎[14]. four samples of drilling fluid were prepared the first :22.5 gm. red bentonite +350 cc water+ potato starch additives, the second sample22.5 gm. red bentonite +350 cc water+ potato starch additives+4gm naoh, the third sample was 22.5gm red bentonite +350 cc water+ starch additives, the last sample was 22.5gm red bentonite +350 cc water+ starch additives+4gm naoh. experimental work was proved that starch appeared better rheological properties than potato starch without naoh. after adding naoh the potato starch showed nearly the same rheological properties of starch as the following: a. plastic viscosities before adding caustic soda to starch, it showed values of plastic viscosity greater than potato starch and as shown in fig. 13. after adding caustic soda the ph reached approximately to 11 and the potato starch showed good values of plastic viscosity, but the starch still better than potato starch as shown in fig. 14. b. yield point the values of yield point of starch were higher than those of potato starch, but after adding naoh both starch and potato starch showed nearly the same values of yield point, as illustrated in fig. 15 and fig. 16 c. 10 min gel strength at low ph (approximately 8.5) potato starch samples were better than starch samples. in contrast, at high ph starch samples were better than potato starch samples, as shown in fig. 17 and fig. 18. d. filtration size and mud cake both of starch and potato starch reduced filtration losses at low and high ph .the reason behind that was reduced filtration which was the primary function of those materials as shown in fig. 19 and fig. 20. fig. 13. the effect of potato starch and starch on plastic viscosity without naoh fig. 14. the effect of potato starch and starch on plastic viscosity with naoh fig. 15. the effect of potato starch and starch on yield point without naoh a.h.assi./ iraqi journal of chemical and petroleum engineering91,3 (2018) 33-40 43 fig. 16. the effect of potato starch and starch on yield point with naoh fig. 17. the effect of potato starch and starch on 10 min gel without naoh fig. 18. the effect of potato starch and starch on 10 min gel with naoh 0 2 4 6 8 10 12 14 0 1 2 3 4 fi lt er s iz e cc potato starch+ starch additives gm. potato starch only starch only fig. 19. the effect of potato starch and starch on filter size without naoh fig. 20. the effect of potato starch and starch on filter size with naoh after reviewing the prices of materials that can act as additives, it was found that potato starch was the cheapest in iraqi market, as shown in fig. 21. fig. 21. the price of potato starch and other polymers in iraqi market until 2017 3.3. effect of ph on potato starch mud it was found that high concentrations of caustic soda led to make high-ph mud which has some desirable features in drilling that are, low value gel strength and high plastic viscosity. as shown in fig. 22, the relation between concentrations of caustic and plastic viscosity showed good increment when the caustic concentrations were between (0.5-6) lb. /bbl. after that, the concentration relation would be inversed. the interpretation is flocculated mud, increase in viscosity .flocculation means a thickening of mud due to edge to edge or edge to face association of the clay particle. flocculation was also caused by high concentration of active solids or by high electrolyte concentration and high temperature. when an electrolyte is added to the drilling fluid, the double layers of clay are compressed, then the particles can approach to each other very closely that attractive forces predominates. this phenomenon is named as flocculation. high degree of flocculation means high particle attractive force. the structure of drilling mud become stronger if the flocculation is accompanied by aggregation. conversely, the deflocculating of mud causes a decrease in plastic viscosity, as illustrated in fig. 18 the deflocculated starts when the concentration of caustic soda was between (610) lb. /bbl. ‎[6]. fig. 22. the effect of adding naoh on the value of plastic viscosity and ph a.h.assi./ iraqi journal of chemical and petroleum engineering91,3 (2018) 33-40 43 4conclusions 1addition of potato starch to bentonite mud led to little increase in pv, yp but after adding naoh to increase ph, the effect of potato starch appeared clearly by high increase in pv, yp. as result the potato starch was effective at high ph media. 2adding potato starch led to decrease filtration at low and high ph. potato starch could be used to enhance gel strength at low ph and viscosifir at high ph value and filter loss additives in all cases. 3potato starch retained fluid better than other starches due to the large size of its molecules. 4according to reviewing the prices of polymers and starches in iraqi markets until 2017, potato starch was the cheapest. 5the experimental work clarified that, at low ph the starch showed good rheological properties than potato starch, while at high ph, both of them nearly showed good rheological properties. 6results from this study have shown that high concentrations of caustic soda led to make high-ph mud which has some desirable features in drilling that are, low value gel strength and high plastic viscosity. the relation between concentrations of caustic soda and plastic viscosity showed good increment when the caustic concentrations were between (0.5-6) lb. / bbl. after that, the concentration relation would be inversed. the interpretation of this behavior is flocculated mud. nomenclature pv: plastic viscosity yp: yield point rpm: revolution per minute lb.: pound gal: gallon bbl.: barrel refrences [1] rabia h."oil well drilling engineering principles and practice" , graham and trotman publishing co.,1985 pp.197 [2] gallus, j. p., "method for drilling with water base mud," u.s. patent no. 3,040,820,june 26, 1962. [3] continual chemical, "sodium hydroxide in the oil and gas industry" , report, usa,2018. [4] hudson ,t.&coffey,m."fluid losses control through the use of a liquid thickened completion and work over brine",journal of petroleum technology,1983,vol35,no.10,pp1776-1782 [5] amanullah ,m.,marsden j."an experimental study of swelling behavior mud rocks in the precence of drilling mud system" , 1997,canadian journal of petroleum tech. vol36,no.3,pp45 [6] darley h.ch. and george r.gray "drilling fluid composition", 5th edition, golf professional publishing ,1988.pp.165-170 [7] ademiluyi, t., joel, o. "investigation of local polymer as a suitable for imported sample in viscosity and fluid loss control of water based drilling mud",2001,arpn journal of engineering and applied science. vol.6, no.12. [8] egun,i.& achandu,m. "comparative performance of cassava starch to pac as fluid loss control agent in water base drilling mud",2013,discovery,vol.3,no.9,pp1-4 [9] ebic. oil field equipment"fluid losses control aid for water based drilling fluids",2015 [10] amoco production company, "drilling fluids manual" (pdf), 1990. [11] grey and darley “handbook of oil based mud technology” 1992,pp.152 [12] baroid drilling handbook. houston, tx 77251, 1998 baroid drilling fluids, inc.pp.22 [13] thomas, d. c., "thermal stability of starch and carboxymethyl cellulose-basedpolymer," soc. petrol. technol j. april, 1982. pp. 171-180. [14] ewa rudnik ,et all "thermal stability and degradation of starch derivatives", journal of thermal analysis and calorimetry.,2006. https://www.onepetro.org/journal-paper/spe-10652-pa https://www.onepetro.org/journal-paper/spe-10652-pa https://www.onepetro.org/journal-paper/spe-10652-pa https://www.onepetro.org/journal-paper/spe-10652-pa https://www.onepetro.org/journal-paper/petsoc-97-03-04 https://www.onepetro.org/journal-paper/petsoc-97-03-04 https://www.onepetro.org/journal-paper/petsoc-97-03-04 https://www.onepetro.org/journal-paper/petsoc-97-03-04 https://www.researchgate.net/profile/ademiluyi_taiwo/publication/260061915_investigation_of_local_polymer_cassava_starch_as_a_substitute_for_imported_sample_in_viscosity_and_fluid_loss_control_of_water_based_drilling_mud_pakistan/links/559d91ab08ae76bed0bb41e6.pdf https://www.researchgate.net/profile/ademiluyi_taiwo/publication/260061915_investigation_of_local_polymer_cassava_starch_as_a_substitute_for_imported_sample_in_viscosity_and_fluid_loss_control_of_water_based_drilling_mud_pakistan/links/559d91ab08ae76bed0bb41e6.pdf https://www.researchgate.net/profile/ademiluyi_taiwo/publication/260061915_investigation_of_local_polymer_cassava_starch_as_a_substitute_for_imported_sample_in_viscosity_and_fluid_loss_control_of_water_based_drilling_mud_pakistan/links/559d91ab08ae76bed0bb41e6.pdf https://www.researchgate.net/profile/ademiluyi_taiwo/publication/260061915_investigation_of_local_polymer_cassava_starch_as_a_substitute_for_imported_sample_in_viscosity_and_fluid_loss_control_of_water_based_drilling_mud_pakistan/links/559d91ab08ae76bed0bb41e6.pdf https://www.researchgate.net/profile/ademiluyi_taiwo/publication/260061915_investigation_of_local_polymer_cassava_starch_as_a_substitute_for_imported_sample_in_viscosity_and_fluid_loss_control_of_water_based_drilling_mud_pakistan/links/559d91ab08ae76bed0bb41e6.pdf https://pdfs.semanticscholar.org/e9de/cb289b16b60a8e5715a644e2db2597f6f54f.pdf https://pdfs.semanticscholar.org/e9de/cb289b16b60a8e5715a644e2db2597f6f54f.pdf https://pdfs.semanticscholar.org/e9de/cb289b16b60a8e5715a644e2db2597f6f54f.pdf https://pdfs.semanticscholar.org/e9de/cb289b16b60a8e5715a644e2db2597f6f54f.pdf https://www.onepetro.org/journal-paper/spe-8463-pa https://www.onepetro.org/journal-paper/spe-8463-pa https://www.onepetro.org/journal-paper/spe-8463-pa https://link.springer.com/article/10.1007/s10973-005-7274-7 https://link.springer.com/article/10.1007/s10973-005-7274-7 https://link.springer.com/article/10.1007/s10973-005-7274-7 a.h.assi./ iraqi journal of chemical and petroleum engineering91,3 (2018) 33-40 34 لتحسين خواص سوائل الحفر نشا البطاطة الخالصة اليمكوه يحم اضافة بعض المواا الوس ئواال ال ووز للوص ل لواا خ وس الموااب المزئابوة لرواال ال ووز الحو ال لاا خ يها بائحمدام طيه ال وز العوا بىحاوايوث ءوابم بمعىوس اتوز يوحم اضوافة ج وص المواا ل لواا خ وس تلووااج ديوودا لروواال ال وووزم جادوود العديوود ءووه الوووداال الم يووة الحوو جرووحمدم لح روويه تووااب ئووااال ال وووز ان ءدى اءكاويوة ائوحمدام و وا الوةاطوة لح رويه الزيالادية الحزشيحم ئ ر ة ءه الحجارب العم ية جم ادزاؤها لوي المااب الزيالادية الحزشيح لرااال ال وزم اظهزت الىحااج باوه يمكه ائحمدام و ا الوةاطا لح ريه الموااب فوان فعاليوة 1م.9جقزيووا الزيالادية الحزشيح لرااال ال وز لكه خىدءا جكان قيمة القاخدية لراال ال ووز خاليوة لوةاطا ف الحاثيز خ س ال ز دة الحزشيح يكان اكثزم العكس صو يح فو لالوة الحواثيز خ وس ءقا ءوة خمل و ا ا فان ءقا ءة الجل جكان ديدا اءا خىد القاخدية 8م1ال وز ق ي ة جقزيوا الجل ليث خىدءا يكان ءقدار القاخدية لراال ( 8-2المثوال لهيدر كرويد اللوا يام هوا ءوه العالية فان المقا ءة جقلم اثوحث الحجارب الممحوزيوة بوان الحزكيوز لكل بزءيل الوه الا ائحمدءىا اكثز ءه هذا الحزكيز فان العالقة بيه ال ز ده وزكيز هيدر كرويد اللوا يام با ود جكان خكرية م جم خمل رائة ج ي ية ججزيوية ل مقاروة بيه ا ااية الوةاطا و ا الوةاطا كاوث الىحااج كالحوال خىدءا يكان قيمة القاخدية ق ي ة فان الى ا ها افضل ءه و ا الوةاطا ف الحاثيز خ س تااب ئاال ال ووزم اءوا فو لالة القاخدية العالية كال الى ا و ا الوةاطا كان لهما ووس اال اايةم وحيجة لذلص يمكه القاا بان و ا الوةاطا يمكه يعمل كمق ل جزشيح ج ريه جمائكية كيكة الةيه كاظيوة ا لية ائحمداءه كالد االضافات ف ئااال ال وز ليث ي ره بعض المااب الزيالادية لراال ال وز كاظيوة ثاوايةم available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol. 24 no.2 (june 2023) 53 – 64 eissn: 2618-0707, pissn: 1997-4884 *corresponding author: name: saif k. al-hlaichi, email: saif.abbas2008m@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. drilling optimization by using advanced drilling techniques in buzurgan oil field saif k. al-hlaichi a, *, faleh h. m. al-mahdawi b, and jagar a. ali c, d a missan oil company, iraqi ministry of oil, iraq b petroleum engineering department, college of engineering, university of baghdad, baghdad, iraq c petrolum engineering department, faculty of engineering, soran university, kurdistan region, erbil, iraq d department of geology, palacký university, 17. listopadu 12, olomouc, 77146, czech republic abstract efficient and cost-effective drilling of directional wells necessitates the implementation of best drilling practices and advanced techniques to optimize drilling operations. failure to adequately consider drilling risks can result in inefficient drilling operations and non-productive time (npt). although advanced drilling techniques may be expensive, they offer promising technical solutions for mitigating drilling risks. this paper aims to demonstrate the effectiveness of advanced drilling techniques in mitigating risks and improving drilling operations when compared to conventional drilling techniques. specifically, the advanced drilling techniques employed in buzurgan oil field, including vertical drilling with mud motor, managed pressure drilling (mpd), rotary steerable system (rss), and expandable liner hanger (elh), are investigated and evaluated through case study analyses, comparing their performance to that of conventional drilling techniques. the findings indicate that vertical drilling with mud motor exhibits superior drilling performance and wellbore verticality compared to conventional rotary drilling bottom hole assemblies (bha) for drilling the 17 ½" hole section. mpd systems employed in the 12 ¼" hole section demonstrate safe drilling operations and higher rates of penetration (rop) than conventional drilling methods. rotary steerable systems exhibit reduced tortuosity and achieve higher rop when compared to mud motor usage in the 8.5" and 6" hole sections. lastly, investigations of expandable liner hanger cases reveal subpar cement quality in the first case and liner remedial work in the second case, highlighting the successful implementation of elh techniques in the offset field. overall, this paper highlights the advantages of utilizing advanced drilling techniques in buzurgan oil field, showcasing their ability to mitigate drilling risks and enhance drilling operations when compared to conventional drilling approaches. keywords: drilling optimization, rotary steerable system (rss), manage pressure drill (mpd), expandable liner hanger (elh). received on 30/08/2022, received in revised form on 07/11/2022, accepted on 09/11/2022, published on 30/06/2023 https://doi.org/10.31699/ijcpe.2023.2.6 1introduction as firms continue to expand their drilling operations in existing oil and gas areas across the globe, the optimization process is still considered to reduce drilling time and associated cost per each well [1]. problems like pipe sticking, overflow, mud loss, hole cleaning, and wellbore instability take up about 20% of all rig time which result in non-productive-time (npt). so, a small change to the npt could save a lot of money. because of these, the drilling is optimized to reduce cost and npt, in addition improving drilling performance and safety. optimization of drilling is a method that relies on optimized well design, computer software, unconventional drilling techniques and experienced personnel [2]. prediction of penetration rate (rop) is important process in optimization of drilling due to its crucial role in lowering drilling operation costs. this process has complex nature due to too many interrelated factors that affected the rate of penetration [3]. horizontal wells are of great interest to the petroleum industry today because they provide an attractive means for improving both production rate and recovery efficiency. the great improvements in drilling technology make it possible to drill horizontal wells with complex trajectories and extended for significant depths [4]. in this modern period, engineering techniques were utilized in every field; consequently, a great deal of technological advancement was observed, especially in vertical and directional drilling technologies, such as the development and application of mud motor in vertical hole drilling and rotary steerable system technology to optimize drilling operations [5]. non-productive time (npt) and operational problems may enhance operational expenses due to downhole pressure uncertainty and circumstances. managed pressure drilling (mpd) provides cost-effective solutions for problematic wells with narrow windows [6]. cemented liner and liner hanger installation need the greatest care and attention. conventional liners have had problems with top consistency, packer/hanger pre-set or fail to set, shoe and cement integrity. an expandable liner http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:saif.abbas2008m@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2023.2.6 s. k. al-hlaichi et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 53 64 54 hanger system (elh) allows rotating and reciprocating of the liner while passing throughout a high dogleg zone. rotation while cementing improve cement quality. high torque expandable liner hanger facilitates washing and reaming down operations in difficult sections and helps run the liner to the optimum depth [7]. 1.1. study area the area of study is buzurgan oil field. this field is located south-east of iraq near the iraqi-iranian borders, about 60 kilometers to the south-east of al-emara city, the center of missan governorate. the structure elongates from the northern-west to the southern-east, consist of two-dome, the southern dome is larger and higher than the northern dome. from top to bottom, the strata drilled in missan oilfields include tertiary upper fars which is mainly clay interbedded with sand, lower fars formation is complex and consists of five members; mb1, mb2, mb3, mb4 and mb5 with lithology thin to thick and massive anhydrite interbedded with shale and salt, as well as the formation pressure is abnormal with 2.2 g/cc expected pressure coefficient. then the formation consists of tertiary jeribe fm. to cretaceous nahr umr fm. cretaceous mishrif carbonate reservoir is the main target interval in buzurgan oilfield, the mishrif is divided into 7 pay zones, namely ma, mb11, mb12, mb21, mb22, mc1 and mc2.the main pay zone is mb21. the common well design type drilled in buzurgan oil field is horizontal well profile [8]. fig. 1 shows a well structure in buzurgan oil field. fig. 1. bucs-86h well structure [8] 1.2. drilling risks the main risks expected for drilling horizontal oil well in buzurgan field are: a. lower drilling performance and wellbore verticality issues when drilling long 17 ½” vertical hole section with conventional rotary bottom hole assembly (bha). b. water and gas overflow, losses and wellbore stability in 12.25” hole section. c. flow gas in 8.25” or 8.5” hole in aliji formation, mud loss in jadala formation, stuck and wellbore instability due to sloughing shale specially tanuma formation. d. lower rate of penetration, wellbore tortuosity by using mud motor with sliding mode in 8.5” hole section. e. lower cement bonding quality and job failure of conventional 7” casing liner. 2workflow steps the workflow to achieve the objectives of this paper is to demonstrate the technical solution to mitigate drilling risks by using unconventional and advanced drilling techniques as follow: 2.1. mud motor effectiveness demonstrate the effectiveness of mud motor to solve the lower rate of penetration in 17.5” hole section by drilling performance comparison with rotary conventional drilling bha by using excel sheet. 2.2. manage pressure drill (mpd) effectiveness demonstrate the effectiveness of manage pressure drill(mpd) technique case study to solve the flow gas, loss, drilling performance and stuck in 12.25” by comparison with normal drilling operation, then discuss implementing this technology to treat downhole problems in 8.25” or 8.5” hole section. 2.3. rotary steerable system (rss) effectiveness demonstrate the effectiveness of the rotary steerable system (rss) field applications to solve the lower rop and wellbore tortuosity in 8.5” hole section by comparison with pdm by using excel sheet. 2.4. expandable liner hanger (elh) effectiveness demonstrate the effectiveness of 7” expandable liner hanger (elh) technique to solve the lower cement bonding quality and job failure reduction by postanalyses two cases study. 3hypothesis 3.1. mud motor in vertical hole drilling drilling vertical hole with motor often doubles or triples the penetration rate compared to standard rotational methods. mud motors work with most drilling fluids. while drilling wellbore between 17 ½" and 26" in diameter, motors may increase penetration over rotary techniques, maintain a vertical wellbore, and reduce drill collar twisting off. vertical hole drilling with motor may s. k. al-hlaichi et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 53 64 55 be cost-effective when appropriately constructed. it has found widespread use in both directional and conventional drilling. fig. 2 depicts the fundamental design of a positive displacement motor. the stator is a rubberized component having a spiral, helical channel. motor choice is dependent upon well specifications [9]. fig. 2. positive displacement motor (pdm) [9] 3.2. managed pressure drill (mpd) technique it is an adapted drilling technique used to adjust the annulus pressure inside the wellbore with greater precision. the goals are to define the pressure environmental constraints and regulate annuals fluid pressure correctly. that may involve controlling choke pressure via an enclosed and pressurized mud returning. managed pressure drilling will often prevent wellbore flow [10]. constant bottom-hole pressure (cbhp) describes ways to modify or decrease circulation friction loss or equivalent circulating density(ecd), maintaining bhp within a pressure window. margin is between limits. low margin is pore pressure and wellbore stability; large margin is differential stuck, lost circulation, and breakdown pressure [11]. fig. 3 explains this technique. fig. 3. mpd constant bottom hole pressure technique [12] a. mpd equipment the main mpd part is rotating control device (rcd) which is primarily responsible for diverting the upstream mud out from the borehole to the mpd choke manifold in the meantime ensuring an effective sealing between the drill string and the wellbore. mpd utilizes a rcd to keep the annulus sealed from the atmosphere. trying to apply an enhanced compound rubber sealant to the drillstring creates a reliable seal while allowing the pipe to move vertically. if the rcd bearing assembly has to be replaced during operation, drill string isolation tool (dsit) is used as a backup. other essential part of mpd is automated mpd choke manifold which manages wellhead pressure by adjusting flow restriction. which helps keep a nearly steady bottom hole pressure under both dynamic and static conditions. the stated choke is a semi-automated choke that can regulate pressures by manually adjusting points on the control unit and keep pressures regardless of upstream flow conditions so that pressure, mud loss and kick can be controlled and detected accurately. fig. 4 below shows choke manifold parts. two-phase separators are necessary for the safe handling of gas in field. separator must be capable of circulating invasion or gas to the surface while handling the plan flow rate and gas rate during the design phase [13]. the mpd layout is shown below in fig. 5. fig. 4. mpd choke manifold system [13] s. k. al-hlaichi et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 53 64 56 fig. 5. mpd equipment layout [13] b. mpd impact value mpd is a basic explanation of the approaches for wellbore pressure management, which covers a variety of concepts describing procedures and equipment created to reduce well kicks, lost circulation, and differential sticking. a beneficial drilling method is one that addresses a real-world issue in a cost-effective way while having little influence on the other components of the drilling operation. using of the mpd techniques in drilling has improved drilling performance, lessened drilling risks, and substantially decreased drilling cost [14]. 3.3. rotary steerable system (rss) one of the most important developments in drilling technology to come out of the petroleum industry in test years has been the introduction of rotary steerable systems, often known as rss. these systems have been shown to be useful for both directional and horizontal drilling. these systems substitute specialized downhole technology for traditional deviated tools, such as drilling mud motor. rss technological system offers well trajectory guidance despite the drill string's continuous rotation. this eliminates the need for an operator to control the well by sliding a mud motor. frequently, these systems use automated drilling modes in which automatic wellbore steering by a closed-loop system programmed into the downhole tool [15]. rss tools are categorized broadly in three types point-the-bit, push-thebit and hybrid system. fig. 6 and fig. 7 describe main components of the point the bit rss and push the bit rss respectively. the system's potential to improve penetration is a major benefit (rop). continuous drill string rotation enhances rop by effectively transmitting weight to the bit. rotation enhances wellbore cleaning by stirring cuttings, enabling them to circulate out of the hole and onto the surface. these features lead to improved hydraulic, weight transfer during drilling, and drilling torque. poor drilling efficiency may cause borehole instabilities in shale zones, resulting in lost time, equipment, and fluids [15]. excessive torque and drag can be critical limitation during drilling horizontal oil wells. using appropriate technique is regarded as an invaluable process to assist in well planning and to predict and prevent drilling problems [16]. as rss enhances drilling performance, an engineer may drill a more complicated well route with less borehole tortuosity. rss hole geometry is less harsh and calibrated compared to motordrilled wells. eliminating ledges and complicated well pathways makes running the well's casing or production string simpler [17]. fig. 6. point the bit rss tool [18] fig. 7. push the bit rss tool [19] 3.4. expandable liner hanger installations of cemented liners and liner hangers have long been regarded as crucial processes requiring the utmost care and attention to ensure operational success. the set cement sheath is the primary annular barrier for s. k. al-hlaichi et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 53 64 57 preserving wellbore integrity and withstanding stresses throughout the well's lifetime. expandable liner hanger systems (elh) are intended to improve the quality of liner cementing and provide a hydraulically activated liner-top seal during setting. this technology has superseded conventional cementing methods [7]. a. comparison of conventional and reciprocating liner hangers conventional liner systems: there are a variety of methods used to connect the liner to the previous casing. liner hanger design consumes a considerable portion of the available surface area to fit the slip-and-cone process and then provide the needed strength to support the liner in place. this offers a severe design challenge when seeking to reduce the od of the assembly. traditional liner hangers with integrated liner top packers separate the formation from the well surface in addition to the main cement. packer components may be fastened mechanically to the hanger's body [20]. fig. 8 shows the conventional liner seal components. the reciprocating expandable liner-hanger (versa flex) system: using expandable liner, trustworthy cementing materials, and servicing facilities. to connect the assembly to the liner, the system employs an expanded liner-hanger structure with an integrated packer, a tieback refined receptacles, a setting-sleeve component, and a cross over component. the hanger's body is bonded using elastomeric components. the elastomer parts inside the annular area are squeezed as the hanger expands. eliminating the hanger/casing annular space increases liner top pressure consistency and tension and compression loadings to remarkable levels [20]. fig. 9 shows the expanding schematic. b. reciprocating liner features and benefits the packer element's design permits large circulation rates. the mechanism rotates over troublesome sections of the hole without releasing the hanger or setting tool. the liner provides enhancing fluid flow due to the lack of external components such as cage, hydraulic cylinder, and slip and others with a more straight-lined flow path directly next to the hangar which decreases surge and ecd. for a given liner length, less stress generation and more uniform stress distribution are created in the supporting casing. the hanger permits cleaning and reaming operations without requiring the hanger to be adjusted. the design features noticed that there is no significant damage to the supporting casing or slips "wickers" that eliminating potential leakage routes. since the hanger is secured after cementing, pipe movement improves zonal isolation across the cemented region and maintains tension and compression for the life of the well that leads to reducing the amount of stages in a process [20]. fig. 8. conventional liner [20] fig. 9. expandable liner hanger [20] 4result and discussion 4.1. mud motor performance in 17.5” or 16” hole section mud motor performances incomparable with rotary conventional bha performance in 17.5” hole section is illustrated in fig. 10. the performance plot shows that the motor drilling rop is significantly higher than conventional rotary bha due substantial motor power generation to bit and providing excellent range of continual torque to the bit moreover isolating the bit from the most damaging consequences of fluctuating torque and speed due to drilling string vibrations. drilling mud motor increase drill string life by reducing drill string rotation and then reduces the drill string twist off. as known, the 17.5” hole section has clay formation tendency that causes drilling npt to maintain wellbore verticality. drilling npt is caused by control parameters with lower wob and high rpm that reduce rop. the significant advantage noticed of using drilling mud motor in 17 ½” hole section is to reduce hole deviation so that inclination angle that measured with electro multshot (ems) or totco survey showed it is less than 1 degree. s. k. al-hlaichi et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 53 64 58 fig. 10. mud motor and conventional bha drilling performance comparison 4.2 managed pressure drill (mpd) a. case study description in 12.25” hole section mpd technology was conducted in north buzurgan oil field. it was run in 12.25” hole section to mitigate the influx in abnormal zone. the constant bottom hole pressure variation is used to optimize the effect of annular pressure loss or ecd density to be within the fracture and pore pressure limits by applying back pressure to maintain bottom hole pressure constant within the limits. case study information is shown in in table 1 below [21]. table 1. mpd case study run information [21] well name hole size (inch) mw (g/cc) ecd (g/cc) flow rate l/min rop (m/hr) section td time (day) fit (emw) g/cc pore pressure psi bucn-59 12.25 2.2 -2.22 2.242.3 2000-2230 5.45 16.145 2.37 2.2 mpd conducted in 12 ¼” hole in bucn-59h. as a result of investigations and analyses of the summary daily reports and comparison this technique with conventional drilling of the offset well, it was found that mpd enhanced well control safety so that overflow was not detected during drilling 12 ¼” with mpd system. the overflow flow occurred many times in other wells of this section specially bucn-57h offset well, also it was occurred severely in bucs-47 so that triple killing methods were made to stop gas overflow and formation fluid inrush that causing costly mud volume to control the well by using mpd system, the gas flow and kick accidents can be early detected if they occurred and mitigating by adjusting higher back pressure to stop influx. finally, mpd system enhance well control safety through early influx detection and treatment resulting of mitigating drilling hazards and associated invisible loss time. second drilling performance shows that the average rop during mpd run is 5.45 m/hr. while average rop the offset well of bucn-55h drilled with conventional drilling is 2.26 m/hr. the double increase of rop belongs to reducing mud weight by using mpd from 2.28 to 2.2 g/cc replacing mud reduction by back pressure. reducing mud weight leads to decrease chip hold down effect that is caused by difference between hydrostatic pressure and formation pressure. drilling 12 ¼” hole section with 2.2 g/cc instead of 2.28 can significantly reduce mud material cost. mpd effectiveness in wellbore stability treatment can be signified to treat stuck pipe accident caused by salt creeping. while drilling 12 ¼” hole section by mpd system to depth 2484.9 m, the drill string was stalled. attempted to pick up drill string at 20 tons, no success. back to neutral and apply torque. string released. according to lithology description at this depth, the formation is salt with 80% interbeded with calystone and anhydrite. then the back pressure increase from 120 psi to 186 psi at ecd 2.3 g/cc. the next operation was running smoothly. finally, no mud losses occurred in this well, the mud loss most likely occurs when drilling 1m into mb1 formation loss layer to set 9-5/8” casing shoe. the mud loss risk can be avoided by mpd system through reducing ecd. the other reason for mud loss accident is to increase mud weight to kill mud because of formation influx. the higher density of killing mud causes mud loss as occurred in bucs-47. this can be mitigated by mpd system through adjusting appropriate back pressure without formation break risk. b. proposed managed pressure drill (mpd) in 8.5” hole section there are expected risks in drilling 8.5” hole section that can be mitigated and solved by mpd if they are occurred.in this section, gas cut mud and mud loss complex situation problem case study description is presented and discussed how the mpd technique can be used to solve the complex situation in addition, mpd technique can be used to mitigate other expected risks in 8.5” hole. gas cut mud treatment gas cut was treated by increasing mud weight to stop gas influx, meanwhile mud loss was s. k. al-hlaichi et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 53 64 59 treated by loss circulation materials (lcm) and four cementing plugs [22]. the table 2 below shows gas cut mud treatment. the table illustrates that the mud weight out is different from mud weight in because of gas cut that dilutes mud column. it is also shown that mud weight is increased gradually to stop gas influx at same time avoiding formation break, but gas is still overflowing resulting mud weight reduction. when the mud weight increased from 1.24 to 1.3 g/cc, the loss occurred causing complex situation. the operator tried obtaining optimum and balanced mud weight to reduce gas overflow and mud loss. after mud weight increasing and mud loss treated with lcm and cementing plugs, it is noticed that 1.34 g/cc -1.36 g/cc mud weight is used to drill this section safely with less gas overflow and without mud loss. the case study impact loss to treat this accident include four cementing plug with 1.9 g/cc cement slurry weight and pump seal mud (lcm) twice with 18.4 m3 volume. the mud loss volume 248.88 m3 in addition mud weighting and conditioning material cost. npt time that is about 24days with 21.4 % percent of whole well time. the complex situation is the wellbore bottom hole pressure management that is difficult to control because the gas cut mud weight density as noticed in table 2 below since mud weight in is different from mud weight out.in addition, mud loss reduces the mud column in wellbore that all make the bottom hole pressure very difficult to control. managed pressure drill (mpd) provides wellbore bottom hole pressure management through controlling surface back pressure to overcome the complex situation. table 2. gas cut mud treatment depth mw. before change mud weight after change @ 3362m (top of alliji) mud in g/cc mud out g/cc mud in g/cc mud out g/cc 1.25 1.24 1.3 1.26 ~1.29 @ 3465 m (top of sadi.) 1.34 1.3 1.38 1.34 @ 3475 m (cont. drilling) 1.38 1.36~ 1.38 1.34 – 1.36 1.34~1.36 suggested mpd technique steps to mitigate the complex situation can be applied through determining actual mud window to provide better understanding for drilling hole condition. when the top of aliji is identified, pore pressure is determined by unbalancing hydrostatic pressure. but additional sbp is applied to make bhp greater than formation pressure. then, bhp is decreased by reducing surface back pressure (sbp) in increments, (i.e. 25 or 50 psi), and monitor flow out. as soon as micro influx is observed, increase bhp quickly by increasing sbp until the gain is circulated out. perform fit to determine equivalent mud weigh by increasing sbp in increments and monitor flow out. as soon as bottom hole equivalent mud is reached, automated mpd choke manifold system will automatically calculate bottom hole pressure and provide information on fit. then, put the hydrostatic pressure in balance or slightly higher than pore pressure then, increase fr to reach optimum flow rate from offset wells for good hole cleaning. after that, control surface back pressure so that bhp is appropriate to drill this section. if gas cut occurred, increase sbp gradually and monitor gas flow out percent to get optimum sbp without gas flow out maintaining ecd less than fit equivalent mud. the important expected risk is in this section is mud loss. the main reason of loss is loss formations that are cavernous or vugular in many formations of this section such us jadal, aliji and hratha formations which formed from limestone lithology, also this section contains depleted reservoir that makes loss risk very high to occur. mud loss costs too much because of mud volume lost, treatment material cost and npt. mud loss risk can be avoided by using mpd technique through controlling optimum ecd by balancing pore pressure with hydrostatic pressure and apply sbp with minimum differential pressure taking in consideration the equivalent mud weight that is taken from fit. differential stuck occurred in many wells drilled in buzurgan oil field because of availability stuck conditions. differential stuck can be mitigated by mpd technique by making the hydrostatic pressure balance with pore pressure and adding sbp with minimal differential pressure, moreover using optimum mud condition. wellbore instability is often demonstrated by sloughing shale, tight hole and caving that cause problems when running casing, mechanical stuck and inefficient hole cleaning , by mpd technique ,the constant bottom hole pressure reduce pressure variations and minimizing wellbore instability and mechanical stuck ,moreover reducing ecd ovoids wellbore erosion, also drilling with lowest overbalance reduce mud filtration and formation damage specially in this section because of reducing oil pay zone damage in mishrif and asmari reservoir. when running drill string to fast can cause surge effect that lead to break weak formation such as jadala formation resulting mud loss problem, in same time pulling the string out too fast can cause swab effect that reduce bottom hole pressure resulting gas influx from aliji, the mpd system allows holding additional pressure to cancel out the swab/surge pressures by maintaining cbhp resulting wiper and short trip time reduction. 4.3. rotary steerable system (rss) rss system was first run in bucn-138h well, recently it was run in bucn-118h and bucn-119h. the main advantages of rop is enhancing rop and reducing operation time. moreover, reducing wellbore tortuosity that lead to smoothen borehole and reducing torque and drag drilling problems. a. drilling performance the rate of penetration of wells drilled with rss shows that rop of bucs-138 is lower rop than others with 3.64 m/hr. while the rop in bucs-118h and bucss. k. al-hlaichi et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 53 64 60 119h is high rop than other wells as illustrated in fig. 11 below. the lower rop in bucs-138 may be caused by inappropriate drilling parameter since it is the first well drilled with rss in addition the bit description after drilling shows better bit condition without damage. on other hand, the high rop of the bucs-118h and bucs119h belongs to eliminating sliding mode time and appropriate drilling and mud parameters. the operation time is defined as the time of make up and run in hole the rss bha in the well to the time of pulling out the rss tool to the surface.as noticed from fig. 12 below, the operation time of the wells drilled with rss are lowest because of higher rop in addition continuous rotation without sliding enhances wellbore cleaning and stability that leads to reducing wiper trip time. the average time saving of the wells drilled with rss compare with wells drilled with mud motor is 29%. it is important to be mentioned, the rss system was run in 6” hole section in bucs-118h.the results showed higher rop and lower operation time than bucs-117h offset well drilled with pdm although the offset well is less footage than bucs-118h as illustrated in table 3 below. fig. 11. rop with rss and mud motor fig. 12. operation time with rss and mud motor table 3. rop and operation time between rss and pdm well name depth in(m) depth out(m) footage wob time(hr.) rop (m/hr.) operation time(hr.) bha bucs-118h 4118 4718 600 46 13.04 145.5 rss+lwd bucs-117h 4077 4527 450 85.02 5.3 164.5 motor+lwd b. wellbore tortuosity as shown in fig. 13 below, the wells drilled with rss showing less tortuosity than wells drilled with mud motor. the reason that makes more tortuous well with motor belongs to drilling directional well with mud motor is made by sliding mode to build angle with desired dogleg and rotation mode to hold the angle. a correction with high dogleg may be needed to maintain designed well path because of bha gravity and formation tendency during rotation. then, adjusting to lower dogleg to follow the planned trajectory. these adjustments lead to more s. k. al-hlaichi et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 53 64 61 tortuous wellbore than made by rss wish eliminates this process by only continuous rotation. lower wellbore tortuosity enhances optimum well placement and running casing. not only that, but also reduces torque and drag drilling problems. fig. 13. rss and pdm absolute tortuosity 4.4. expandable liner hanger (elh) a. first case study 7” x 9 5/8” expandable liner hanger is first run in bucs-117h well at 4075m set depth. casing specifications are vam 95/vam 21 /weight: 129 b/ft.m/u and rih 7” liner casing to 1418m then, then m/u and rih liner hanger to shoe depth. circulate hole with 48 spm and keep work string up and down. later, preform cementing job and setting packer. the packer was set at 3300psi and slack off weight 30ton to release string tool, pick up string tool, and come free and the weight drop off to 46 tons (liner weight). then, reverse circulation was made leading to successful string tool release and liner expansion [23]. b. second case study 7” x 9 5/8” expandable liner hanger is second run in bucn-120 well at 4085.5m set depth. casing specifications are vam 95/vam 21 /weight: 129 b/ft. m/u and rih 7” liner casing to 1447m then, m/u liner hanger and rih liner to shoe circulation and mud condition there is no reciprocating and rotation during mud conditioning and cementing. preform successful cementing job. the thickening time was 348 mins for lead slurry while the thickening time was 231 min. setting hanger procedure was performed by pumping pressure to 600 psi and 1000 at the f/r of 0.159 m3/min by cement pump, there was returns in well head, then stopped pumping immediately, total 4bbls was pumped, design expansion pressure:2800-3500psi.the expansion of hanger cannot be confirmed, then started the emergency expansion operation by dropping the setting ball to verify the setting. dropped the 2.5 setting ball on rig floor, make sure the ball leaves the cement head, and waited for 30min.then pumped the pressure to 1080psi at the f/r of 0.159 m3/min by cement pump, the pressure dropped to 600 psi, and there was returns in well head, 1.1bbls volume was pumped. there was still 500psi left after stop the pumping. finally, running tool was released by applying pick up weight with 200t and slack off weight with 110t, not released, connect tds, limited torque of 10 kn·m, s/to 60t, p/u to 215t, continue s/o to 55t, p/u the who dropped to 130t, successful release. reverse circulation, hold pressure 913 psi. lay down cement head. pulled out drilling pipes. found out that they cannot be moved, drill pipe stuck. treat with accident [24]. c. expandable liner hanger postanalyses case studies the major of reciprocating liner advantages that should be applied to say successful reciprocating liner are reciprocating liner through conditioning mud and displacing cement, liner top seal and good cement evaluation. liner in first case (bucn-117h) was reciprocated during mud conditioning with 48 spm by keep work string up and down. but reciprocating and rotation were not made during cement displacement because of operator request.in contrast with second case(busc-120) there was no reciprocating through mud conditioning and cement displacement. the first case showed that the liner hanger was expanded and running tool was released normally within 20 minutes so that liner expansion and top seal was tested successfully by weight and hydraulic. while in second case, liner expansion conformity issue and difficult running tool release results stuck pipe. the root cause of stuck pipe accident that halliburton liner hanger (versaflex) failed to work normally according to the design in the process of expansion and releasing the running tool. it took too long to operate repeatedly and finally take emergency measures. cement pump and displacement took 160min from the time @22:25 when the cement slurry was pumped to the time when cement displacement finished at bump pressure 2900 psi @01:05 as shown in fig. 14 below. expansion conformity issue and releasing running tool treatments took 150 minute from time 01:10 at which setting hanger procedure was started to 03:00 at which reverse circulation was made as shown in fig. 15 below. hows that the pressure was held at 6.4 mpa and the circulation is blocked that gives indication that thickening time starts to begin.in addition, the total time consumed from cement pumping to reverse circulation is 310 min. which is very close to the time when the slurry thickening time （t. t 348 min for cementing slurry). so that the drilling pipe could not be pulled out of hole. evaluation of first case (bucn-117h) showed that cement bond 33.12% poor, 40.8 medium and 26.08 good.it is important to mention the 175 m above shoe was not covered by cbmt. while the second case showed that the overlap cementing bond is poor, therefore, 7” casing tie-back was run. the table 4 below showed that versaflex application in offset field. table 4 shows that liner rotation applied with 10/15 rpm with successful top seal and installation in addition good cement bonding in comparison with conventional liner hanger. s. k. al-hlaichi et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 53 64 62 fig. 14. end time of liner cementing job fig. 15. reverse circulation end time table 4. reciprocating liner job parameter well name rotation (rpm) & reciprocating(m) torque(klb.ft) top liner test (psi) remedial squeeze required while mud condition while cement displacement while mud condition while cement displacement x-1 15rpm rotate 3m recipro. 10rpm rotate 3m recipro. 18 20 3000*15min ok. no x-2 10rpm rotate 5m recipro. 10rpm rotate 5m recipro. 18 18 3000*15min ok. no x-3 10rpm rotate 5m recipro. 10rpm rotate 5m recipro. 9 9 3000*15min ok. no x-4 15rpm rotate 3m recipro. 10rmp rotate 3m recipro. 4 3 3000*15min ok. no 5conclusion according to the obtained results from this study, the conclusions have been reached that mud motor provides higher drilling performance (rop) and wellbore verticality in comparison with conventional bottom hole assembly(bha) in vertical drilling section. because of higher rop and reduced npt caused by wellbore deviation, the total well cost will be decreased in spite of the higher mud motor cost. although it is more expensive, mpd system shows several advantages through drilling 12.25” hole section through increasing drilling performance, wellbore stability and well control safety, but it is more effective to treat with drilling risks in 8.5” hole section specially gas cut mud complex situation treatment and other risks expected in this section. because of eliminating sliding mode in rotary steerable system, the rop in rss is higher in 8.5” hole and 6 “hole than pdm, also rss enhances wellbore quality through reducing wellbore tortuosity in comparison with pdm. higher cementing quality can be obtained if expandable liner hanger is rotated and reciprocated in first case study. second case job contingency plan was delayed that lead to stuck pipe accident. although expandable liner hanger is more expensive than conventional liner, but it is still magnificent technology for cementing improvement, top seal consistency and remedial job reduction as shown in offset field jobs. nomenclature bucn north buzurgan well bucs south buzurgan well cbhp constant bottom hole pressure cbl cement bond log ddr daily drilling report ecd equivalent circulating density elh expandable liner hanger system fit formation integrity test npt non-productive-time masp maximum allowable surface pressure md measure depth mpd managed pressure drilling mw mud weight pdm positive displacement motor ptb point the bit ptb push the bit rcd rotating control device rop rate of penetration rss rotary steerable system sbp surface back pressure references [1] m. m. majeed and a. a. alhaleem, “enhancing drilling parameters in majnoon oilfield,” iraqi j. chem. pet. eng., vol. 20, no. 2, pp. 71–75, 2019, https://doi.org/10.31699/ijcpe.2019.2.9 [2] d. c. k. chen, “new drilling optimization technologies make drilling more efficient,” can. int. pet. conf. 2004, cipc 2004, 2004, https://doi.org/10.2118/2004-020 [3] k. hmood mnati and h. abdul hadi, “prediction of penetration rate and cost with artificial neural network for alhafaya oil field,” iraqi j. chem. pet. eng., vol. 19, no. 4, pp. 21–27, 2018, https://doi.org/10.31699/ijcpe.2018.4.3 https://doi.org/10.31699/ijcpe.2019.2.9 https://doi.org/10.2118/2004-020 https://doi.org/10.31699/ijcpe.2018.4.3 s. k. al-hlaichi et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 53 64 63 [4] s.al-jawad, m., al-dabaj, a., & abdul hadi abdul hussien, h. (2014). design of horizontal well program for ajeel field. iraqi journal of chemical and petroleum engineering, 15(1), 59–63. [5] a. q. shaikh, a. h. tunio, s. riaz, w. arshad, and h. sargani, “technical performance analysis of rss and mud motors: a case study,” int. j. curr. eng. technol., vol. 10, no. 06, pp. 924–928, 2022, https://doi.org/10.14741/ijcet/v.10.6.5 [6] o. gabaldon, r. g. luis, p. brand, s. saber, a. kozlov, and w. bacon, “an integrated approach for well design optimization with mpd and its impact on value,” soc. pet. eng. spe/iadc manage. press. drill. underbalanced oper. conf. exhib. 2020, mpdu 2020, 2020, https://doi.org/10.2118/200509ms [7] q. k. song, h. wang, w. dong, r. bradshaw, w. cui, and j. njoku, “investigating the benefits of rotating liner cementing and impact factors,” soc. pet. eng. iadc/spe asia pacific drill. technol. conf., 2016, https://doi.org/10.2118/180578-ms [8] buzurgan field operation division, cnooc, “drilling program for bu-well.” p. 184, 2017. [9] m. izadi, m. t. ghomi, and g. pircheraghi, “mechanical strength improvement of mud motor’s elastomer by nano clay and prediction the working life via strain energy,” int. j. eng. trans. b appl., vol. 32, no. 2, pp. 184–191, 2019, doi: 10.5829/ije.2019.32.02b.20 [10] o. gabaldon, r. g. luis, p. brand, s. saber, a. kozlov, and w. bacon, “an integrated approach for well design optimization with mpd and its impact on value,” soc. pet. eng. spe/iadc manag. press. drill. underbalanced oper. conf. exhib. 2020, mpdu 2020, https://doi.org/10.2118/200509-ms [11] j. custer, r. van kuilenburg, a. johnson, and s. hovland, “managed pressure drilling optimized design and future strategy,” soc. pet. eng. spe/iadc manag. press. drill. underbalanced oper. conf. exhib. 2018, 2018, https://doi.org/10.2118/190003-ms [12] b. a. dhayea, f. h. m. almahdawi, and s. i. m. alshaibani, “using of surface back pressure with water based mud in managed pressure drilling technique to solve lost circulation problem in southern iraqi oil fields,” j. pet. res. stud., vol. 11, no. 3, pp. 28–47, 2021, https://doi.org/10.52716/jprs.v11i3.531 [13] p. vieira et al., “constant bottomhole pressure: managed-pressure drilling technique applied in an exploratory well in saudi arabia,” soc. pet. eng. north africa tech. conf. exhib. 2008 “exploration prod. challenges north africa,” pp. 546–559, 2008, https://doi.org/10.2118/113679-ms [14] s. hovland, r. van kuilenburg, n. drilling, t. eide, c. stridsklev, and c. munro, “lessons learned with real integration of a deepwater mpd control system,” soc. pet. eng. iadc/spe manag. press. drill. underbalanced oper. conf. exhib. 2019, mpdu 2019, 2019, https://doi.org/10.2118/194543-ms [15] j. clegg, c. mejia, and s. farley, “a paradigm in rotary steerable drilling market demands drive a new solution,” spe/iadc drill. conf. proc., vol. 2019-march, 2019, https://doi.org/10.2118/194170ms [16] c. hansen et al., “automated trajectory drilling for rotary steerable systems,” spe/iadc drill. conf. proc., vol. 2020-march, 2020, https://doi.org/10.2118/199647-ms [17] a. q. shaikh, a. h. tunio, s. riaz, w. arshad, and h. sargani, “technical performance analysis of rss and mud motors: a case study,” int. j. curr. eng. technol., vol. 10, no. 06, pp. 924–928, 2022, https://doi.org/10.14741/ijcet/v.10.6.5 [18] m. boushahri et al., “true point-the-bit rss upgrades meets well placement challenges in high build rate application: a case study from kuwait,” proc. spe/iadc middle east drill. technol. conf. exhib., vol. 2016-january, 2016, https://doi.org/10.2118/178147-ms [19] h. wang, z. c. guan, y. c. shi, and d. y. liang, “study on build-up rate of push-the-bit rotary steerable bottom hole assembly,” j. appl. sci. eng., vol. 20, no. 3, pp. 401–408, 2017, https://doi.org/10.6180/jase.2017.20.3.15 [20] t. jackson, b. watson, and l. moran, “development of an expandable liner hanger with increased annular flow area,” proc. spe annu. tech. conf. exhib., vol. 6, pp. 3722–3729, 2008, https://doi.org/10.2118/116261-ms [21] cnooc iraq, “final drilling report well bucn59,” missan oil company, iraq, 2017. [22] cnooc iraq, “final drilling report well bucs49,” missan oil company, iraq, 2015. [23] cnooc iraq, “final drilling report well bucs117h,” missan oil company, iraq, 2020. [24] cnooc iraq, “final drilling report well bucn120,” missan oil company, iraq, 2020. https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/269 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/269 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/269 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/269 https://doi.org/10.14741/ijcet/v.10.6.5 https://doi.org/10.2118/200509-ms https://doi.org/10.2118/200509-ms https://doi.org/10.2118/180578-ms https://doi.org/10.2118/200509-ms https://doi.org/10.2118/190003-ms https://doi.org/10.52716/jprs.v11i3.531 https://doi.org/10.2118/113679-ms https://doi.org/10.2118/194543-ms https://doi.org/10.2118/194170-ms https://doi.org/10.2118/194170-ms https://doi.org/10.2118/178147-ms https://doi.org/10.6180/jase.2017.20.3.15 https://doi.org/10.2118/116261-ms s. k. al-hlaichi et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 53 64 64 تقنيات الحفر المتقدمة في حقل البزركان النفطي أمثلية الحفر بواسطة استخدام 4، 3علي و جكر عزيز ، 2 فالح حسن محمد المهداوي ،، *1 سيف خضير عباس العراقشركة نفط ميسان، وزارة النفط، 1 العراق، جامعة بغدادقسم هندسة النفط، كلية الهندسة، 2 العراق، جامعة سوران ،كلية الهندسة ،قسم هندسة النفط 3 تشيكجمهورية ال، اولوموك، جامعة باالسكي، قسم علم األرض 4 الخالصة لحفر يتطلب حفر البئر االتجاهي الفعال واالقتصادي أفضل الممارسات لعمليات الحفر اضافة الى تقنيات ا ت حفر المتقدمة لتحسين عمليات الحفر. إذا لم تؤخذ مخاطر الحفر بنظر االعتبار، فإنها سوف تؤدي إلى عمليا مخاطر أفضل الحلول التقنية للتعامل مع غير فعالة ووقت حفر غير منتج. يمكن اعتبار تقنيات الحفر المتقدمة دمة منالحفر على الرغم من أنها ذات كلفة عالية. الهدف من هذا البحث هو معرفة فاعلية تقنيات الحفر المتق ة لمتقدماأن تقلل من مخاطر الحفر وتعزز عملية الحفر مقارنتًا بتقنيات الحفر التقليدية. تشمل تقنيات الحفر ، ونظام الحفر ((mpd، والحفر ثابت الضغط البزركان الحفر العمودي بالموتورنفط المستخدمة في حقل يمها بحيث هذه التقنيات يتم فحصها وتقي ((elhوالبطانة المعلقة بواسطة التوسيع ((rssالموجه بالتدوير وتور بالم لحفر العموديبناًء على تحليالت دراسة الحاالت المستخدمة مقارنتًا بتقنيات الحفر التقليدية. اثبت ا ر أثبت نظام الحف. بوصة 17.5ني التقليدي لحفر مقطع أداء حفر أعلى وانحراف قليل جدا من الحفر الدورا بوصة عملية حفر آمنة وأدائية حفر أعلى من الحفر التقليدي. 12.25في حفر مقطع ((mpdثابت الضغط 8.5في حفر المقطع وكذلك اثبت نظام الحفر الموجه بالتدوير أقل تعرجيه وأعلى أدائية للحفر من الموتور ، كشفت نتائج دراسة حاالت البطانة المعلقة بواسطة التوسيع عن ضعف جودة . أخيًرابوصة 6بوصة و حة في الناج لحالة األولى وعملية استصالح للفشل في البطانة في الحالة الثانية مقارنتًا بالعملياتاإلسمنت في ا .الحقول المجاورة .يع، البطانة المعلقة بواسطة التوسامثلية الحفر، والحفر ثابت الضغط، نظام الحفر الموجه بالتدوير الكلمات الدالة: 9 iraqi journal of chemical and petroleum engineering vol.12 no.2 (june 2011) 9 17 issn: 1997-4884 cracking activity of prepared y-zeolite catalyst using cumene on fluidized bed reactor prof. dr. abdul halim a.k. mohammed, rawa ghassan yousuf and karim khalifa esgair* university of baghdad, college of engineering, chemical engineering department, *foundation of technical education abstract the catalytic activity of faujasite type nay catalysts prepared from local clay (kaolin) with different si/al ratio was studied using cumene cracking as a model for catalytic cracking process in the temperature range of 450-525° c, weight hourly space velocity (whsv) of 5-20 h 1 , particle size ≤75µm and atmospheric pressure. the catalytic activity was investigated using experimental laboratory plant scale of fluidized bed reactor. it was found that the cumene conversion increases with increasing temperature and decreasing whsv. at 525° c and whsv 5 h -1 , the conversion was 42.36 and 35.43 mol% for catalyst with 3.54 si/al ratio and catalyst with 5.75 si/al ratio, respectively, while at 450° c and at the same whsv, the conversion was decreased to 29.15 and 21.86 mol% respectively, and the catalyst of 5.75 si/al ratio gave the higher cumene activity than the catalyst with 3.54 si/al ratio. keywords: fluid catalytic cracking; cumene cracking; benzene production introducation catalytic cracking breaks complex hydrocarbons into simpler molecules in order to increase the quality and quantity of lighter, more desirable products and decrease the amount of petroleum residua. this process rearranges the molecular structure of hydrocarbon compounds to convert heavy hydrocarbon feedstock into lighter fractions such as lpg, gasoline, kerosene heating oil, and petrochemical feedstock [1]. zeolites are the alumina silicate members of the family of micro porous solids known as „‟molecular sieve„‟ because zeolite has the capacity to selective adsorption of molecules based on their size. there are 40 types of natural zeolites that have been found, in addition, the number of synthetic zeolite has increased to more than 150[2]. plank and nace [3] studied the cumene cracking and coke formation over silica -alumina at 8001000 f and 2-6 h -1 lhsv in fixed bed reactor and found that when temperature increases the conversion of cumene increases, and decreases as lhsv increases. peter et al. [4] studied dealkylation of cumene over zeolite y in hydrogen form pretreated at temperatures between 500 and 800° c and they found that the main products were benzene and propylene and they calculated the conversion data from the concentration of benzene in the product. iraqi journal of chemical and petroleum engineering university of baghdad college of engineering cracking activity of prepared y-zeolite catalyst using cumene on fluidized bed reator 10 corma and wojciechowski [5] studied the kinetics of cumene cracking over an hy zeolite catalyst at atmospheric pressure and at temperatures of 360, 430, and 500° c. the rate constant for dealkylation as well as the decay parameters have thus been determined. these parameters are compared with those obtained using a lay catalyst, and the observed differences are discussed in terms of the nature and number of bronsted sites in the two catalysts. these conclude that the nature of the active sites is identical in the two catalysts, but that hy has a greater number of active sites per unit weight. albert gomezplata, and w. w. shuster [6] studied the effect of uniformity of fluidization on the catalytic cracking of cumene, with a silica alumina catalyst, in a 3 in.-diameter reactor operated at 527° c. superficial gas velocities were varied from 0.06 to 0.24 ft./sec. for bed heights of 1.5, 3, 5, and 8 in. the percentage conversion in a fluidized bed was found to be lower than in a fixed bed .it was noted that the first few inches of bed are very effective in bringing in contact the continuous and discontinuous phase, and therefore most of the conversion due to the interaction of the two phases takes place here. corma and wojciechowski [7] studied the initial selectivities for primary products in the catalytic cracking of cumene on hy and lay zeolite catalysts in an integral fixed bed glass tubular reactor. it was observed that the reac-tion products and their characteristics behavior have been found to be the same for both lay and hy zeolites at 360, 430, and 500° c which are due to the similarity in the nature of the active sites in both catalysts. the obtained selectivity for benzene ranged from 0.16 to 0.94 and from 0.65 to 0.94 mol % over hy and lay zeolites, respectively. the aim of the present work is study the performance of prepared catalysts from kaolin of aldewekhala quarry, alenbar region using cumene as a feedstock for fluid catalytic reaction. experimental feedstock cumene (isopropyl benzene) supplied by bdh with 98% purity and boiling point of 423 k was used as a raw material for fluidized catalytic cracking activity test. kaolin clay kaolin clay available in al-dewekhala quarry in alenbar region was used as raw material for catalyst preparation. table 1 shows the chemical analysis of this material. table 1 chemical analysis of kaolin l.o.i = loss on ignition catalyst preparation preparation of catalyst with 3.542 si/al ratio: mixture of 300 g sodium hydroxide with 200 g kaolin was prepared and heating at 900° c for 4 hr, after that, this mixture added to 400 g of sodium silicate dispersed in 450 ml of deionized water under constant stirring for 2 hr to product the slurry with ph =12.6. this product was aged at 60° c for 25 hr. the temperature increases to 110° c for 60 h for crystallization process. the crystalline mass is then washed with deionized water until a ph =11. the results powder was dried at 100° c for 20 hr, after that the produced catalyst was milled into a fine powder, and sieved to a particle size ≤ 75 µm. preparation of catalyst with 5.758si/al ratio: 100 g of prepared catalyst with 3.542 si/al ratio was stirred with 1 liter of 2 n hydrochloric acid solution, for 3 hrs at 80° c. component weight % sio2 53.2 al2o3 32.13 fe2o3 1.41 na2o 0.35 mgo 0.21 cao 0.13 tio2 0.41 l.o.i 12.00 prof. dr. abdul halim a.k. mohammed, rawa ghassan yousuf and karim khalifa esgair 11 the stirring was done at the same apparatus. the product was carefully washed with large quantities of deionized water to free of all chloride ions, and dried at 110° c for 5 h. the dried zeolite was calcined for 5 h at 550° c. the prepared catalyst then subjected to chem.-ical analysis for sio2/al2o3 ratio determination [8]. fcc experiment the fcc experiments were carried out at temperature range 450 to 525°c, whsv ra-nge 5 to 25 h -1 ,catalyst practical size ≤75µm, and atmospheric pressure. figure 1 represents the schematic flow diagram of the fluidized catalytic cracking system. 13 fig. 1 schematic flow diagram of the fluidized catalytic cracking system: (1) burette cumene feeding; (2) burette water feeding; (3) valve; (4) dosing pump; (5) three way valve; (6) preheated section; (7) fluidized bed reaction section; (8) catalyst charge inlet;(9) reactor separation section; (10) chilled water in; (11) chilled water out; (12) control panel; (13) separation and collection flask ; (14) water tank ; (15) gas collection ; (16) double pipe heat exchanger ; (17) internal tube ice water bath ; (18) distributor (19) ice water bath . 6 6 6 9 12 16 14 19 4 3 3 1 2 8 7 5 15 11 1 10 18 17 cracking activity of prepared y-zeolite catalyst using cumene on fluidized bed reator 12 analytical method reaction products composition was determined by gas chromatographic analysis (packed 438a located in ibn sina state company). the chromatograph used has a flame ionization detector and column type cpsil 5cb with an inside diameter of 0.25 mm and length 50 m. the oven temperature of the gas chromatography is programmed at inlet temperature 75° c and raised to 110° c at rate 50 c/min. injection temperature was 250° c. the carrier gas used for chromate-graphic analysis was pure helium. results and discussions x-ray diffraction x-ray diffraction was used to study the crystalline and framework structure of zeolites. figure 2 represent the x-ray diffraction pattern of the prepared with 3.54 si/al ratio catalyst. this pattern was compared with x-ray data of standard y-zeolite (figure 3)[9]. table 2 shows that the lattice spacing of prepared catalyst sample gave similar lattice spacing of standard synthesis faujasite-na. this means that the prepared catalyst has approximately the same crystal structure as the standard type y-zeolite. prepared catalyst standard synthesis faujasite na [10] angle (2theta) deg. d,spacing (å) angle(2theta)deg. d,spacing (å) 12.536 7.055 12.47 7.09 20.386 4.352 19.80 4.48 21.703 4.0914 21.76 4.08 26.847 3.318 26.74 3.33 28.127 3.1699 28.21 3.16 29.444 3.031 29.55 3.02 31.151 2.868 30.94 2.88 32.396 2.761 32.26 2.77 33.414 2.679 33.49 2.67 35.864 2.5018 35.95 2.49 38.135 2.357 38.16 2.35 38.485 2.33 39.27 2.29 figure 2 x-ray diffraction spectrum for the prepared catalyst. in te n si ty ( a r b it r a r y u n it s ) 2θ º (degree) in te n si ty ( a r b it r a r y u n it s) 2θ º (degree) figure 3 x -ray diffraction spectrum for the standard zeolite y [9]. table 2 comparison of lattice spacing, between prepared catalyst and standard synthesis faujasite -na prof. dr. abdul halim a.k. mohammed, rawa ghassan yousuf and karim khalifa esgair 13 0 5 10 15 20 25 30 35 40 45 50 0 2 4 6 8 co n v e rs io n ( m o l % ) u0/umf effect of superficial gas velocity on cumene conversion the effect of the ratio of superficial gas velocity to minimum fluidization velocity (uo/umf) on the cumene conversion was investigated in the range of 2 6. experiments were performed at different weights of prepared nay catalyst to vary the uo/umf ratio at constant weight hour space velocity. the experimental conditions of these tests are whsv of 10 h -1 , reaction temperature of 500° c. figure 4 show the effect of uo/umf ratio on the conversion. it is seen that the cumene conversion is affected by the inlet gas velocity, when the uo/umf ratio increases the cumene conversion also increase up to uo/umf five times, after that the conver-sion slightly decreases. therefore the value of uo/umf equal five will be selected for the study. this result was agree with karim [11] the experimental conditions of these tests are whsv of 10 hr -1 , reaction temperature of 480 o c, and atmospheric pressure. effect of temperature figure 5 and 6 shows the effect of temperature on cumene conversion for catalyst with 3.54 si/al ratio and catalyst with 5.75 si/al ratio respectively. at 525° c and whsv 5 h -1 , the conversions are 34.22 and 41.97 mol% for catalyst with 3.54 si/al ratio and catalyst with 5.75 si/al ratio respectively, while at 450° c using the same whsv the conversion reach 22.37 and 28.64 mol% respectively. as shown in these figures, the cumene conversion increases with increasing the temperature. this is may be attributed to the increase of active sites that can be used for reaction when the temperature increases and accelerates the intermolecular motion which enhances the rate of reaction. these observa-tions are well agreed with the results reported by karim et al.[11], donalad and wojciechowski [12], wollaston et al.[13], at 500° c and whsv 10 h -1 10 h -1 at 480° c and whsv 10 h -1 [71] 0 5 10 15 20 25 30 35 40 440 460 480 500 520 540 c o n v e rs io n ( % ) temperature (° c ) t=5 c t=10 c t=15 c t=20 c fig. 5 effect of temperature on conversion at different whsv for catalyst with 3.54 si/al ratio. fig. 4 effect of uo/umf ratio on the cumene. conversn. whsv=5 h -1 whsv=10 h -1 whsv=15 h -1 whsv=20 h -1 cracking activity of prepared y-zeolite catalyst using cumene on fluidized bed reator 14 effect of whsv effect of whsv figure 7 and 8 shows the effect of whsv on cumene conversion for catalyst with si/al 3.542 ratio and catalyst with si/al 5.75 ratio respectively. at 525° c and whsv 5 h -1 , the conversions are 29.4 and 35.1 mol% for catalyst with si/al 3.542 ratio and catalyst with si/al 5.75 ratio respectively while at 450° c using the same whsv the conversion reach 22.3 and 32.6 mol% respectively. these figures show that, the cumene conversion increase with decreasing of whsv at constant temperature. this means that decreasing in the whsv offers a plenty of contact time for cumene with catalysts. these observation are well agreed with the results reported by plank and nace [3], wollaston et al.[13], samar et al.[14]. 0 5 10 15 20 25 30 35 40 45 400 450 500 550 c o n v e rs io n ( % ) temperture ( ° c ) t=5 t=10 t=15 t=20 fig. 6 effect of temperature on conversion at differ-ent whsv for catalyst with 5.75 si/al ratio. 0 5 10 15 20 25 30 35 40 45 0 10 20 30 c o n v e rs io n ( m o l % ) whsv ( h-1) t=450 c t=475 c t=500 c t=525c2 fig. 7 effect of whsv on cumene conversion at different temperatures catalyst with si/al 3.542 ratio. 0 5 10 15 20 25 30 35 40 0 10 20 30 c o n v e rs io n ( % ) whsv ( h-1 ) t=450 c t=475 c t=500 c t=525 c fig. 8 effect of whsv on cumene conversion at different temperatures catalyst with si/al 5.758. ratio. whsv=5 h -1 whsv=10 h -1 whsv=15 h -1 whsv=20 h -1 prof. dr. abdul halim a.k. mohammed, rawa ghassan yousuf and karim khalifa esgair 15 comparison between the performance of cat-alyst x and y zeolite prepared from iraqi kaolin. the performance of y-zeolite prepared from iraqi clay (al dewekhala) according to this steady was compared with xzeolite prepared by other author [14] from the same clay and using cumene as a model for cracking reaction. the ratio of silica to alumina ratio for prepared y-zeolite 3.54 and 5.75 while 2.8 x-zeolite for prepared. figure 9 shows the effect of space time (1/whsv) on the conversion obtained for the two mentioned catalyst at 500° c. this figure clearly indicates that the yzeolite prepared in this steady gave higher conversion at the same space time. for example the conversion obtained from yzeolite 3.54 and 5.758 si/al, while xzeolite with 2.8 si/al at space time 0.4 h-1 are 40, 48 and 18 mol% respectively. this is may be due to the high si/al ratio of y-zeolite. this observation well agrees with previous investigation reported by break et al. [16]. conclusions 1the comparison of the x-ray diffraction prepared nay zeolite catalyst with that of standard shows that the prepared catalyst is approximately y-zeolite. 2cumene conversion and benzene yield increase with temperature increasing from 450° c to 525° c and decrease with whsv increasing from 5-10 h -1 for both catalysts. 3the catalyst of 5.75 si/al ratios gave higher cumene conversion than the catalyst with 3.54 si/al ratio. 4the experimental results indicate that the effect of whsv higher than the effect of temperature on the cumene conversion within the process variable 5y-zeolite gave higher conversion than x-zeolite at the same operating condition and using the same clay for preparation. references 1-john dwyer and david rawlence, “fluid catalytic cracking catalyst with heavy residual feedstocks”.volume 18, issue4, pages 487-507,december(1993). 2robert l. virta ,”zeolite ”. u.s. geological survey publication, vol. 74, no.11, november (1993). 3-plank ,c.j.,and nace , d.m.,„‟coke formation and its relationship to cumene cracking „‟, ind. eng .chem., vol.47 , no.11,(1955). 4-peter,a.j.,hugo,e.and jan b.l.,‟‟active site in zeolite:cumene activity after different prtreatments‟‟,j .cata., vol.33,17-30,(1974). 5corma , a. and wojciechowski ,b.w.,‟‟ the nature of the active sites in the reaction of cumene on hy and lay catalyst „‟, the canadian journal of chemical engineering ,vol.58,(1980). 6-albert gomez plata ,and w.w .shuster ,”effect of uniformity of fluidization on 0 5 10 15 20 25 30 35 40 45 50 0 0.5 1 1.5 co v e rs io n ( m o l % ) 1/whsv (h) y-zeolite with 3.54 si/al 3.542 si/a ssssssssss si/alratio y-zeolite with 5.75 si/al x-zeolite with 2.8 si/al [6] fig.9 the effect of conversion and 1/whsv for prepared catalysts at 500 ° c. http://www.sciencedirect.com/science?_ob=publicationurl&_tockey=%23toc%235226%231993%23999819995%23258334%23flp%23&_cdi=5226&_pubtype=j&view=c&_auth=y&_acct=c000050221&_version=1&_urlversion=0&_userid=10&md5=0162c41e057d6cf19647fc3987625a56 http://www.sciencedirect.com/science?_ob=publicationurl&_tockey=%23toc%235226%231993%23999819995%23258334%23flp%23&_cdi=5226&_pubtype=j&view=c&_auth=y&_acct=c000050221&_version=1&_urlversion=0&_userid=10&md5=0162c41e057d6cf19647fc3987625a56 cracking activity of prepared y-zeolite catalyst using cumene on fluidized bed reator 16 catalytic cracking of cumene”. american chemical engineer-in.,new york ,vol.6, issue 3, page 454-459 , (1999). 7-corma and wojciechowski.k. ,” synthesis and characterization of zsm-5 zeolite possess in gnano particles agglega-tion”. american chemical engineering, page 2115,( 2007). 8-shatha abd al-hameed rasheed,„‟effect of catalyst activity on hydroc-onversion of n-hexane‟‟. m.sc. thesis, university of techn-ology, (2007). 9 international center for diffraction data (icdd) ,12 campus boulevard ,newtown square, pa 19073-3273,u.s.a,( 2009) . 10shannon, k.h. gardner, r.h. staley, g. bergeret, p. gallezot, a.auroux, j.,„‟ion exchange ultrastable y zeolite :3gas oil cracking over rare earth. exchanged ultrastable“. phys. chem. 89 ,4778-4788, (1985). 11karim . kh. e.‟‟fluid catalytic cracking of petroleum fraction (vacuum gas oil) to produce gasoline„‟, ph.d. thesis .university of baghdad, (2010). 12-donald , b.,and wojciechowski ,b.w.,‟‟ on identifying the primary and secondary pro-ducts of the catalytic cracking of cumene„,j.cata.,vol.47,11,(1977). 13wallenstein, d., sees, m., zhaob, x., “a novel selectivity test for the evaluation of fcc catalysts” applied catalysis a: general 231 227–242 , (2002). 14-samar.k.dh,“catalytic dealkylation of cumene”. m.sc. thesis, univ-ersity of baghdad,(2008). 15break, d. w., “zeolite molecular sieves structure chemistry and use”, john wiley and sons, new york, (1974). prof. dr. abdul halim a.k. mohammed, rawa ghassan yousuf and karim khalifa esgair 17 انخالصت حى دساست انفعبنٍت انحفبصٌت نهعبيم انًسبعذ انًحضش يٍ انكبؤنٍٍ انًحهً وبُسب يخخهفت يٍ انسهٍكب انى االنويٍُب ببسخخذاو انكٍويٍٍ 20-5دسجت سهٍضٌت وسشعت فشاغٍت بٍٍ 525-450 كًودٌم نهخكسٍش انحفبصي انًبئع ببسخحذاو دسجبث حشاسٌت بٍٍ سب 1 .يبٌكشويخش فً وحذة حجشٌبٍت وببسخخذاو يفبعم رو انطبقت انًًٍعت75 وحجى جضٌئبث اصغش او ٌسبوي وجذ اٌ َسبت انخحول نهكٍويٍٍ وكزنك َسبت حكوٌٍ انبُضٌٍ حضداد ببسحفبع دسجبث انحشاسة وَقصبٌ انسشعت 525انفشاغٍت حٍث كبَج َسبت انخحول عُذ دسجت حشاسة o c 5 وسشعت فشاغٍت %42.3 و 35.43% 450 عهى انخوانً عُذ دسجت انحشاسة5.758 و 423.5نهعبيم انًسبعذ روَسبت انسهٍكب انى االنويٍُب o c . نهعبيهٍٍ عهى انخوانً %21.86 و 29.15وبُفس انسشعت انفشاغٍت نوحظ َسبت انخحول قذ اَخفض انى available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.21 no.1 (march 2020) 61 – 66 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: karrar ahmed mohammed, email: karrarahmed2002@gmail.com, name: ayad a. al-haleem, email: ayadah62@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. optimization of hole cleaning and cuttings removal in high inclined till horizontal well karrar ahmed mohammed and ayad a. al-haleem engineering college-baghdad university abstract the goal of this experimental study is to determine the effects of different parameters (flow rate, cuttings density, cuttings size, and hole inclination degree) on hole cleaning efficiency. freshwater was used as a drilling fluid in this experiment. the experiments were conducted by using flow loop consist of approximately 14 m (46 ft) long with transparent glass test section of 3m (9.84 ft.) long with 4 inches (101.6 mm) id, the inner metal drill pipe with 2 inches (50.8 mm) od settled with eccentric position positive 0.5. the results obtained from this study show that the hole cleanings efficiency become better with high flow rate (21 m3/hr) and it increase as the hole inclination angles increased from 60 to 90 degree due to dominated of the rolling force. the cuttings size has negative influence on cuttings recovered as size increased and that is true for all cuttings specific gravity due to direct effect of the cuttings size and density on the gravity force which work against lifting force. the increasing of hole inclination angle above 60 degree will affect positively on cuttings removal efficiency. keywords: hole cleaning, high deviated well, horizontal well received on 40/11/8412, accepted on 12/18/8412, published on 30/03/8420 https://doi.org/10.31699/ijcpe.2020.1.9 1introduction many of directional wells have been drilled around the world in the last few years. directional well can be used effectively in the following application ‎[1]: 1in naturally fractured reservoirs because it is the best choice to drill a directional well with (90 degree angle) to intersect fractures and drain them effectively. 2in reservoirs with water and gas conning. 3it can be used in low and high permeability, so it is better to be used in gas production. 4in eor applications, especially in thermal eor. 5drilling into the reservoir where vertical access is difficult or not possible. 6drilling a relief well, etc. a lot of variables play an important role in hole cleaning and cuttings transportation such as inclination degree of the well, angle, the inner diameter of hole and the outer diameter of drill pipe, drill pipe rotation speed, eccentricity of drill pipe in wellbore, rate of penetration (rop), size of cuttings, bed porosity, drilling fluids features such as flow rate and velocity, regime of the flow, and mud rheology ‎[2]. for this purpose, numerous researchers work on cutting transportation error! reference source not found., error! reference source not found., error! reference source not found.. different branches have been studied by various researchers in dealing with cuttings removal difficulty issues with the drilling process parameters have been mistakenly applied, so it is very necessary to recap the drilling parameters to three groups according to the ability of direct controlling these parameters or not, these groups are ‎[6]: 1input parameters (effectiveness parameters) such as mud weight, hook load, flow rate, mud type, hole angle, hole size, rotary speed, bit type, lithology. 2output parameters (directly affected parameters) such as effective circulating density (ecd), cspp, torque, p/u weight, rotated string weight, cutting the returned rate on shale shaker, returned mud density, rate of penetration. 3inner state (results due to change in input parameters) such as pipe eccentricity, cuttings size, the regime of the flow, height of the cuttings bed, annular cuttings concentration, weight on bit (w.o.b). https://doi.org/10.31699/ijcpe.2020.1.9 k. a. mohammed and a. a. al-haleem / iraqi journal of chemical and petroleum engineering 21,1 (2020) 61 66 26 2experimental work 2.1. cuttings transport flow loop design in order to conduct the experimental program, the cuttings transport flow loop was built to investigate the effect of different parameters on hole cleaning. a schematic diagram and picture of the flow loop have been shown in fig. 1. (a) (b) (c) fig. 1. a. cuttings transport flow loop, b. cuttings transport flow loop, c. cuttings transport flow loop (schematic diagram) flow loop specially designed to permit the change in the inclination degree of the test section with various parameters used in this experiment. the experiments were conducted by using flow loop consist of approximately 14 m (46 ft) long with a transparent glass test section of 3m (9.84 ft.) long with 4 inches (101.6 mm) id, the inner metal drill pipe with 2 inches (50.8 mm) od settled with eccentric position positive 0.5. the fluid feed line made from pvc with 4 inch id as long of 8 m and the main function is to transport the drilling fluid to test section and in position, while it near the inlet of the test section the cuttings are injected to flow to pass as two phases(cuttings-drilling fluid) during the test section. the test section was attached to the feed line through the movable joint in order to change the degree of test section inclination. all experiments were conducted under ambient temperature and atmospheric pressure conditions. the drilling fluid is mixed in a mixing tank of 1 m3 (1000 liters) where the liquid is supply to the feed line. table 1 summarized the values of the variables used in this experiment table 1. range of variables used in the experiment parameter range of value annulus length, m (ft) 5 m (16.4 ft) annulus od x id, mm (in) 101.6 mmx50.8 mm,(4 in.x2 in.) annulus inclination, degree 90°, 80°, 70°, 60° flow rate, m 3 /hr. (gpm) 15 – 21 m 3 /hr. (66 – 92.5 gpm) rop, m./hr. (ft./hr.) 1 m/hr. (3.28 ft./hr.) inner pipe eccentricity 0.5 particle size, mm (in.) 1.7 and 3.35mm (0.0661 and 0.132 in.) particle specific gravity limestone (2.7) and limestone-dolomite (2.6) drilling fluid used water 2.2. experimental procedure the cuttings amount that should be injected to each test simulated rop was calculated to both kinds of cuttings used in these experiments, the procedure for calculating was as follow: assuming cutting rop=1 m/hr. cuttings volume= area of annulus * rate of penetration * solid fraction cutting v. = л r 2 * rop * (1-ϕ) = л (0.05) 2 * 0.0166 * (1-0.22) = 0.000101 m 3 /hr. for limestone cutting multiply by specific gravity 2.4 gm/cc cutting injection rate = 0.000101 * 2.4 * 1000000 = 242.4gm/min. for limestone-dolomite cutting multiply by specific gravity 2.6 gm/cc cutting injection rate = 0.000101 * 2.6 * 1000000 = 262.6 gm/min. k. a. mohammed and a. a. al-haleem / iraqi journal of chemical and petroleum engineering 21,1 (2020) 61 66 26 a brief description of the experimental work steps followed during the execution of the experiments is presented as follow: 1adjusted degree of inclination (90 – 80 -70 – 60) degree. 2adjusted all other factors involved in these experiments:  cuttings type limestone and limestone-dolomite.  cuttings size two ranges (1.7 and 3.36 mm).  annular velocity two ranges (0.685 and 1.051 m/sec.). 3start the pump and adjust the liquid flow rate (65 and 100 gpm). 4wait for flow pattern stabilization. 5inject the cuttings that simulated the desired rop. 6collect the outlet cutting from the sieve screen, to calculate the cuttings recovered. 7circulate with high flow rate to clean the annulus from remain cuttings after test. 8stop the pump. 3results and discussion table 2 shows the experimental results of cuttings recovered cr% for different values of flow rate with different values of parameters ( hole inclination angle, cuttings type and size). 3.1. effect of superficial velocity on cuttings delivered concentration the importance of getting turbulent flow is very necessary to agitate the cuttings bed and get the cuttings transported mechanisms to be converted to suspension mechanisms (especially in hole inclination above 60 degrees where the stationary/moving bed mechanisms are dominated). in high inclined wellbore, the engineers should design drilling fluids that able to decrease the slip velocity with a flow profile that maximizes the velocity under the eccentric drill pipe. the results for this experiment show that the flow rate is the most effective parameter that has a direct influence on cuttings removal even with a change in the value of all other parameters, as shown in fig. 2. it should be mentioned that the increment in flow rate indicates more pressure drop but after some points, the pressure drop starts to decrease due to reduction in the cuttings bed and by means increasing the area open for flow ‎[7], ‎[8]. table 2. cuttings recovered percent for different parameters flow rate m 3 /hr. velocity ft./sec angle cuttings type cutting size δp m bar cuttings transported gm cr% 15 2.248 90 lime 1.7 13 25 10.29 15 2.248 90 lime 3.35 13.5 8 3.29 15 2.248 90 lime-dolo 1.7 13 27 10.27 15 2.248 90 lime-dolo 3.35 14 7 2.66 15 2.248 80 lime 1.7 17 7.00 15 2.248 80 lime 3.35 6 2.47 15 2.248 80 lime-dolo 1.7 8 3.04 15 2.248 80 lime-dolo 3.35 7 2.66 15 2.248 70 lime 1.7 14 5.76 15 2.248 70 lime 3.35 10 4.12 15 2.248 70 lime-dolo 1.7 20 7.60 15 2.248 70 lime-dolo 3.35 8 3.04 15 2.248 60 lime 1.7 14 5.76 15 2.248 60 lime 3.35 12 4.94 15 2.248 60 lime-dolo 1.7 20 7.60 15 2.248 60 lime-dolo 3.35 6 2.28 21 3.447 90 lime 1.7 22 200 82.30 21 3.447 90 lime 3.35 22 200 82.30 21 3.447 90 lime-dolo 1.7 25 180 68.44 21 3.447 90 lime-dolo 3.35 25.5 145 55.13 21 3.447 80 lime 1.7 201 82.72 21 3.447 80 lime 3.35 180 74.07 21 3.447 80 lime-dolo 1.7 201 76.43 21 3.447 80 lime-dolo 3.35 91 34.60 21 3.447 70 lime 1.7 200 82.30 21 3.447 70 lime 3.35 170 69.96 21 3.447 70 lime-dolo 1.7 120 45.63 21 3.447 70 lime-dolo 3.35 90 34.22 21 3.447 60 lime 1.7 170 69.96 21 3.447 60 lime 3.35 150 61.73 21 3.447 60 lime-dolo 1.7 100 38.02 21 3.447 60 lime-dolo 3.35 95 36.12 k. a. mohammed and a. a. al-haleem / iraqi journal of chemical and petroleum engineering 21,1 (2020) 61 66 26 fig. 2. fluid superficial velocity, ft./sec vs. cr% with 1.7 mm limestone cuttings 3.2. hole inclination angle effect on cuttings delivered concentration the hole inclination angle of the wellbore is an important parameter that effect on the hole cleaning and all other parameters should maintain according to the degree of inclination, that because hole inclination effect on phenomena of cuttings flows while drilling fluids and also affect and change the percent that the forces influences on the particles movements. previous studies have established the majority of the effect of hole inclination on cuttings transport and show that the toughest section for hole cleaning is the middle section (40-60 degree) due to a combination of beds avalanching, boycott settling, and an asymmetrical flow profile ‎[9]. angles above 60 degree it’s also difficult to be cleaned due to the dominated of the radial components of the slip velocity and that help to build a more thick and tough cuttings bed. in that case, the attention should be paid to prevent the cuttings bed from forming and convert the cuttings transportation phenomena to suspension mechanisms, and that can be achieved by increasing the flow rate to get as can as possible a turbulent flow that can agitate the bed and transport the cuttings in suspension and that can be seen clearly as a results of this experiments in fig. 3. these figures the cuttings recovered percent is plotted against the inclination angle of the well with different flow rates and cuttings size, and for fixed cuttings specific gravity. 3.3. cuttings density and size effect on delivered cuttings concentration cuttings density has a direct influence on the cuttings slip velocity and that influence dominated clearly in nearvertical well angles but for the horizontal and nearhorizontal well the influence of the cuttings density has a direct influence on the gravity force and by means on the lifting/sliding force of the cuttings bed and that clearly observed in fig. 4. the size of the drilled cuttings also has a big influence on the bed height and cuttings recovered percent since the size of that large cutting has a tendency to form bed and roll along the low side of the wellbore, as proved in previous studies ‎[10], ‎[11]. the cuttings with large size at high angles (65° and more) tend to form stationary bed at the low side of the well, in that case, and with the absence of the pipe rotation, only the high flow rate can disturb the bed and achieve a homogeneous suspension, as shown in fig. 5. fig. 3. hole inclination angle vs. cr % for limestone cuttings type fig. 4. cuttings s.g. vs. cr% for 3.35 mm in size with fr=21m 3 /hr fig. 5. cr% vs. cuttings size, mm for limestone with 0.8 kg/m 3 polymer and fr=21 m 3 /hr k. a. mohammed and a. a. al-haleem / iraqi journal of chemical and petroleum engineering 21,1 (2020) 61 66 26 4conclusions 1experimental results for different hole inclinations angles, different cuttings type, and sizes with different drilling fluid types showed that the fluid velocity is the most effective parameter that can improve hole cleaning. 2in high deviated well (more than 60°) the cuttings density effect has a direct influence on the gravity force that effects on the cuttings, and that means more cuttings deposition will occur in the annulus as the density increased. 3the results indicate that cuttings size also influences on hole cleaning efficiency. for different hole inclinations and flow rates with different drilling fluids type the increment in cuttings size will affect negatively the efficiency of hole cleanings, the size of the small cutting is easier to carry out of the annulus. 4hole inclination angles effect the cuttings delivered concentration by changing the percent of the effect of the force on the particles inside the wellbore. the increase in the degree of inclination above 60° has less effect on hole cleaning and that proved by the results of this experiment. references [1] s. okrajni and j. azar, jan. 1986, “the effects of mud rheology on annular hole cleaning in directional wells,” spe drilling engineering, vol. 1, no. 04, pp. 297–308. [2] d. power, c. hight, d. weisinger, and c. rimer, 2000, “drilling practices and sweep selection for efficient hole cleaning in deviated wellbores” iadc/spe asia pacific drilling technology. [3] f. h. m. al-mahdawi and k. saad, “enhancement of drilling fluid properties using nanoparticles”, ijcpe, vol. 19, no. 2, pp. 21-26, jun. 2018. [4] a. assi, “potato starch for enhancing the properties of the drilling fluids”, ijcpe, vol. 19, no. 3, pp. 33-40, sep. 2018. [5] h. neamah and a. a.alrazzaq, “torque and drag forces problems in highly deviated oil well”, ijcpe, vol. 19, no. 3, pp. 19-31, sep. 2018. [6] j. d. ytrehus, i. m. carlsen, j. c. melchiorsen, j. abdollahi, p. skalle, a. saasen, m. a. taghipour, a. reyes, n. v. d. t. opedal, and b. lund, 2013, “experimental study of friction and cutting transport in non-circular borehole geometry” spe/iadc middle east drilling technology conference & exhibition. [7] j. ford, j. peden, m. oyeneyin, e. gao, and r. zarrough, 1990, “experimental investigation of drilled cuttings transport in inclined boreholes” proceedings of spe annual technical conference and exhibition, pp. 197–206. [8] j. li and s. walker, may 2001, “sensitivity analysis of hole cleaning parameters in directional wells” spe/icota coiled tubing roundtable, pp. 356–363. [9] j. mitchell, 2001, “trouble-free drilling”, pre-edition., vol. 1. woodlands, tx: drilbert engineering. [10] nada sabah, 2007, “experimental study of cuttings transportation in horizontal wells”, ph.d. dissertation, university of baghdad, college of engineering. [11] raed hamed, 2017, “experimental study of hole cleaning in directional wells” m.s. thesis, college of engineering, university of baghdad. nomenclatures rpm rotation per minute. id, od inner and outer diameter, mm. h.p. horse power. fr flow rate, m 3 /hr. ecd equivalent circulation density, ppg. cspp casing shut in pipe pressure, psi. w.o.b. weight on bit, ton. rop rate of penetration, m/hr. https://www.onepetro.org/journal-paper/spe-14178-pa https://www.onepetro.org/journal-paper/spe-14178-pa https://www.onepetro.org/journal-paper/spe-14178-pa https://www.onepetro.org/journal-paper/spe-14178-pa https://www.onepetro.org/conference-paper/spe-62794-ms https://www.onepetro.org/conference-paper/spe-62794-ms https://www.onepetro.org/conference-paper/spe-62794-ms https://www.onepetro.org/conference-paper/spe-62794-ms https://www.onepetro.org/conference-paper/spe-62794-ms http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/162 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/162 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/162 https://doi.org/10.31699/ijcpe.2018.3.4 https://doi.org/10.31699/ijcpe.2018.3.4 https://doi.org/10.31699/ijcpe.2018.3.4 https://doi.org/10.31699/ijcpe.2018.3.3 https://doi.org/10.31699/ijcpe.2018.3.3 https://doi.org/10.31699/ijcpe.2018.3.3 https://www.onepetro.org/conference-paper/spe-166790-ms https://www.onepetro.org/conference-paper/spe-166790-ms https://www.onepetro.org/conference-paper/spe-166790-ms https://www.onepetro.org/conference-paper/spe-166790-ms https://www.onepetro.org/conference-paper/spe-166790-ms https://www.onepetro.org/conference-paper/spe-166790-ms https://www.onepetro.org/conference-paper/spe-166790-ms https://www.onepetro.org/conference-paper/spe-20421-ms https://www.onepetro.org/conference-paper/spe-20421-ms https://www.onepetro.org/conference-paper/spe-20421-ms https://www.onepetro.org/conference-paper/spe-20421-ms https://www.onepetro.org/conference-paper/spe-20421-ms https://www.onepetro.org/journal-paper/spe-74710-pa https://www.onepetro.org/journal-paper/spe-74710-pa https://www.onepetro.org/journal-paper/spe-74710-pa https://www.onepetro.org/journal-paper/spe-74710-pa https://www.wellcontrol.com/content/pdf/marketing-material/wcs_trouble_free_drilling.pdf https://www.wellcontrol.com/content/pdf/marketing-material/wcs_trouble_free_drilling.pdf k. a. mohammed and a. a. al-haleem / iraqi journal of chemical and petroleum engineering 21,1 (2020) 61 66 22 أمثمية تنظيف البئر و رفع القطع الصخرية في االبار االفقية و شديدة الميالن ياد عبد الحميم عبد الرزاقا و كرار أحمد محمد جامعة بغداد-كمية اليندسة الخالصة ىو الستبيان تأثير مختمف العوامل )تدفق سائل الحفر, كثافة وحجم القطع اليدف من ىذه الدراسة العممية الصخرية, زاوية ميالن البئر( عمى كفاءة تنظيف البئر. الماء العذب تم استخدامو في ىذه التجربة كسائل حفر. تار قدم( طول مع مقطع تجريبي مصنوع من الزجاج بطول ثالثة ام 14متر ) 41منظومة الجريان تتألف من ممم( ...8انج ) 2ممم(, االنبوب الداخمي المعدني بقطر خارجي 4.4.4انج ) 1قدم( مع قطر داخمي 1..4) . النتائج المستحصمة من ىذه التجربة بينت ان كفاءة تنظيف البئر 8..متموضع بالمركزية مقدارىا موجب اد الكفاءة مع زيادة درجة ميالن متر مكعب لكل ساعة( وتزد 24تصبح افضل مع زيادة تدفق سائل الحفر ) درجة وذلك لزيادة تأثير قوة التدحرج. حجم القطع الصخرية لو تأثير سمبي عمى .4الى .4زاوية البئر من حجم القطع الصخرية المستحصمة وىذا ينطبق عمى جميع كثافات القطع الصخرية المستخدمة وذلك لتأثيرىا قطع المحفورة والتي تعمل بالضد من قوة الرفع. الزيادة في زاوية ميالن المباشر عمى قوة الجاذبية االرضية لم درجة تؤثر ايجابيا عمى كفاءة رفع القطع الصخرية. .4البئر اكثر من أفقي بئر عالي، انحراف ،الحفر الكممات الدالة: تنظيف available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.19 no.3 (september 2018) 41 – 45 issn: 1997-4884 corresponding authors: samaher a. lazim, email: samaher2013@yahoo.com, sameera m. hamd-allah, email: sameerahamdulla@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. permeability estimation for carbonate reservoir (case study/ south iraqi field) samaher a. lazim a , sameera m. hamd-allah b and ali hussain jawad c a petroleum technology department/ uni. of technology b petroleum eng. dept./college of eng./ baghdad uni. c ministry of oil/ iraq abstract the heterogeneity nature of carbonate reservoirs shows sever scattering of the data, therefore, one has to be cautious in using the permeabilityporosity correlation for calculating permeability unless a good correlation coefficient is available. in addition, a permeabilityporosity correlation technique is not enough by itself since simulation studies also require more accurate tools for reservoir description and diagnosis of flow and non-flow units. evaluation of reservoir characterization was conducted by this paper for mishrif formation in south iraqi oil field (heterogeneous carbonate reservoir), namely the permeability-porosity correlation, the hydraulic units (hu’s) and global hydraulic elements (ghe) methods depending on reservoir quality index(rqi) concepts. keywords: permeability, carbonate reservoir,mishrif formation, ghe. received on 30/05/2013, accepted on 22/05/2018, published on 30l09l2018 https://www.doi.org/10.31699/ijcpe.2018.3.5 1introduction knowledge of permeability distribution is critical to effective reservoir description. carbonate reservoirs consist of limestone and dolomite, they are generally less homogeneous than clastic reservoirs and have a wide range of grain size distributions. typically carbonates have very low matrix permeability, as low as 0.1 to 1.0 md in some cases, but carbonates often have extensive natural fracture systems. significant permeability is possible from secondary porosity associated with features such as vugs and oolites. permeability and permeability distribution are usually determined from core data. however, most wells are often not cored, as a result, permeability is estimated in uncored sections/ wells from permeability versus porosity relationships that are often developed from statistically insignificant data sets. 2discussion 2.1. relationship of porosity to permeability for core plugs data the extreme petrophysical heterogeneity found in carbonate reservoirs is clearly demonstrated by the wide variability observed in porositypermeability cross-plots of core analysis data. permeability in particular, can vary by a factor of 10 or more at the small scale and is nearly randomly distributed. correlation between porosity and permeability for a particular rock type is a basic procedure applied in core data interpretation. however, this correlation may not always be satisfactory because of pore heterogeneity and pore geometry. in general, the log of permeability is linear with porosity for a given rock type, however, the precise relationship is found only through direct measurements of representative rock samples. in uncored wells or zones, empirical permeability is estimated from log derived porosity using the following equation: (1) there is apparently no theoretical basis to support the traditional cross plot of the logarithmic of permeability versus porosity. permeability is plotted as log function only because it appears to be log-normally distributed. on the classical plot, the relationship between permeability and porosity is not causal. whereas porosity is generally dependent of grain size, permeability is strongly dependent on grain size, for example, in a reservoir, porosity and permeability may, in general, be directly proportional. however, in the same reservoir, there may be both high and low permeability zones. the core plug porosity values for some drilling wells in the studied reservoir (mishrif fm.) are plotted against logarithm of air permeability, fig. 1. a linear regression was run between them and the resulting equation is: https://www.doi.org/10.31699/ijcpe.2018.3.5 s. a. lazim, et al. / iraqi journal of chemical and petroleum engineering19,3 (2018) 41-45 24 (2) the regression coefficient (r 2 ) was obtained as (63.55 %) meaning that there exists an unreasonable relation between the parameters. an increase in porosity is followed by an increase in permeability, but for samples, the amount of increase in porosity is not directly proportional to permeability, due to of isolated pores that do not contribute to permeability. fig. 1. permeabilityporosity relationship from core plugs/ mishrif formation 2.2. permeability estimation by using global hydraulic element (ghe) method a. hydraulic unit (hu)concept characterization of carbonate reservoir into flow units is a practical way of reservoir zonation. the presence of distinct units with particular petrophysical characteristics such as porosity, permeability, water saturation, pore researches to establish strong reservoir characterization. the earlier in the life of a reservoir the flow unit determination is done, the greater the understanding of the future reservoir performance. a quality and the future performance of a reservoir are controlled by hydrocarbon storage and flow capacity. these help to define intervals of similar and predictable flow characteristics, which are the flow units. the term flow unit has been used originally to describe the correlation units in reservoirs ‎[4]. a flow unit (or hydraulic flow unit) is defined as the representative elementary volume of total reservoir rock within which geological and petrophysical properties that affect fluid flow are internally consistent and predictably different from properties of other rock volumes ‎[1] & ‎[7], introduced the term “flow unit” to describe geological units within a stratigraphic framework that have petrophysical properties within certain ranges. the hu ' s for a hydrocarbon reservoir can be determined from core analysis data (porosity & permeability). this technique has been introduced by ‎[1] and involved calculating the flow zone indicator (fzi) from the pore volume to solid volume ratio (φz) and reservoir quality index (rqi) via equation (3): √ ( ) (3) all available porosity and permeability data from core plugs analyses for six wells were used to develop a representative training data base for hu classification. when plotting rqi versus φz on loglog scale, all core samples with similar fzi values will lie on a straight line with a unit slop ‎[1]. other core samples that have different fzi values lie on other parallel lines. unfortunately, this is not always the case, in fact‎[2]& ‎[6] showed that natural rock systems tend to show various slops rather than having a fixed slop as suggested by ‎[1] and the k-c model, fig. 2. from fzi values, samples can be classified into different hu’s. samples with a similar fzi value belong to the same hu. ‎[8] & ‎[9], fig. 3 shows the hu approach which applied to mishrif formation in the studied field where three distinct hu’s are evident with different number of hu and these were defined by different fzi relationships. accordingly, the porositypermeability relationships for different hu systems were estimated. fig. 2. rqi vs. φz relationships for different hu systems y = 2.5156x1.0004 r² = 0.8926 y = 0.7928x1.415 r² = 0.7323 y = 1.2811x1.0899 r² = 0.8748 0.001 0.01 0.1 1 10 0.01 0.1 1 r q i phi z s. a. lazim, et al. / iraqi journal of chemical and petroleum engineering19,3 (2018) 41-45 24 fig. 3. porositypermeability relationships for different hu systems b. global hydraulic element (ghe) petrophysists have long tried to define a hydrocarbon bearing reservoir as a limited set of elements number with unique characteristic of each one. to address this issue, ‎[1] introduced the first approach of the hydraulic flow units (hfu) concept. this concept was successful in determining different systems in a single data set, such as a cored well, but this method has one major limitation, that different hfu , s were found in each well. this limitation is overcomed by the new concept of petrotyping using global hydraulic elements (ghe) which was developed in a series of studies ‎[3], ‎[5] & ‎[10]. the ghe approach also based on flow zone indicator (fzi) values from the same underlying theory as hydraulic units (hu). however, the selecting of a systematic series of fzi values allows determination of hydraulic unit (hu) boundaries to define ten global hydraulic elements that can be applied to any reservoir formation. the definition of these boundaries is arbitrary chosen in order to split a wide region of possible combinations of porosity and permeability into a manageable number of global hydraulic elements, ‎[4] & ‎[5]. petrophysical rock typing is a necessity in carbonate reservoirs. occasionally it will occure as a single ghe class (unipetrotype) such as the case of chalk, which is a texturally controlled media with a very fine grain size, so simpler relationships may be observed, i.e. carbonate reservoirs can have simple (unipetrotype, such as a chalk) to very complex (multipetrotype) distributions of ghe , s. the ghe approach sets a framework for determining how many rock types are needed for reservoir description, and can be used for permeability prediction. for a given porosity, the permeability can be calculated by a rearrangement of equation (3) as follows: * ( ) + (4) and using this equation, lines for constant fzi can be determined. the global h ydraulic element (ghe) approach has been applied for the studied area (tuba oil field, mishrif formation/ basra) to improve the reservoir description and identify significant trends of mishrif formation. four global hydraulic elements are identified for drilling wells in the studied reservoir. the ghe template identifies three poroperm clusters, fig. 4, which can be modeled using a simple fzi value about which to distribute permeability for a given porosity, fzi of (0.28 ) for cluster (1), ( 0.75 ) for cluster ( 2 ), and (2.2) for cluster (3). fig. 4. porositypermeability data drawn on standard ghe plot y = 0.6336e 22.295x r 2 = 0.9027 y = 5861x 3.5733 r 2 = 0.9509 y = 2317.9x 4.2503 r 2 = 0.8182 0.001 0.01 0.1 1 10 100 1000 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 phi (frac.) p e rm e a b il it y ( m d ) hu0 hu1 hu2 power (hu2) power (hu1) power (hu0) s. a. lazim, et al. / iraqi journal of chemical and petroleum engineering19,3 (2018) 41-45 22 3conclusions 1the routine and special core analysis (scal) data and core description data are taken as “ground truth” for petrophysical model calibration. over (272) of core from (6) wells have been obtained, described, and analyzed. 2carbonate rock data show scattering and poor correlation on permeability vs. porosity plot, thus, it is better to use the three relationships among porosity and permeability to represent rock types for permeability calculation. 3three relationships of permeabilityporosity for mishrif fm. which is carbonate reservoir in the studied field were estimated according to different hu’s systems and depending on reservoir quality index (rqi) concepts. 4three poroperm clusters for the reservoir under study could be found by the ghe template in which fzi values should be used to estimate permeability for a given porosity. nomenclature fzi : flow zone indicator, µm hu : hydraulic flow unit k : permeability, md rqi : reservoir quality index, µm greek symbols φ : porosity, fraction φz : normalized porosity index, fraction references [1] amaefule, j.o., et al.; 1993.” enhanced reservoir description: using core and log data to identify hydraulic (flow) units and predict permeability in uncored intervals/ wells”. spe paper 26436, annual technical conference and exhibition, houston, texas. [2] civan, f.; 2002: “fractal formulation of the porosity and permeability relationship resulting in a powerlaw flow units equationa leakytube model.” spe 73785, spe international symposium and exhibition on formation damage control, lafayette, louisiana. [3] corbett, p. w. m., ellabad, y., mohammed, k., &posysoev, a.; 2003.”global hydraulic elements: elementary petrophysics for reduced reservoir modeling.” european association of geoscientists and engineers 65 th conference (eage), annual technical meeting. [4] corbett p.w.m. and potter d.k.; 2004 "petrotyping: a basemap and atlas for navigating through permeability and porosity data for reservoir comparison and permeability prediction". institute of petroleum engineering, heriot-watt university, edinburgh, eh14 4as, uk this paper was prepared for presentation at the international symposium of the society of core analysts held in abu dhabi, uae. [5] ebanks, w. j., jr. scheihing, m. h., & atkinson, c.d.; 1992: “flow unit for reservoir characterization in development geology reference manual.” morton-thompson and woods (eds.) aapg methods in exploration 10, p. 282-285. [6] haro, c.f.; 2004: “the perfect permeability transform using logs and cores.” spe 89516, annual technical conference and exhibition, houston, texas. [7] hearn, c.l. ebanks, w.j. tye. r.s.&ranganathan. v.; 1984: “geological factors influencing reservoir performance of hartzog draw fieldwyoming.” jpt v. 36, no. 9, p. 1335-1344. [8] mohammed, k.; 2002: “petro physical characterization of solution seams and optimization of hydraulic units in a clastic reservoir.” ph.d. thesis, heriot watt university, 300p. [9] mohammed, k.& corbett, p.w.m.; 2002: “ how many relative permeability measurements do you need? a case study from a north african reservoir” proceedings of the 2002 international symposium of the society of core analysts, paper sca 2002-03. [10] svrisky, d., ryazanov, a., pankov, m., corbett, p.w.m., &posysoev, a.; 2004: “hydraulic flow units resolve reservoir description challenges in a siberian oil field.” spe 87056, spe asia pacific conference on integrated modelling for asset management, kuala lumpur, malaysia. https://www.onepetro.org/conference-paper/spe-26436-ms https://www.onepetro.org/conference-paper/spe-26436-ms https://www.onepetro.org/conference-paper/spe-26436-ms https://www.onepetro.org/conference-paper/spe-26436-ms https://www.onepetro.org/conference-paper/spe-26436-ms https://www.onepetro.org/conference-paper/spe-26436-ms https://www.onepetro.org/conference-paper/spe-73785-ms https://www.onepetro.org/conference-paper/spe-73785-ms https://www.onepetro.org/conference-paper/spe-73785-ms https://www.onepetro.org/conference-paper/spe-73785-ms https://www.onepetro.org/conference-paper/spe-73785-ms https://www.onepetro.org/conference-paper/spe-73785-ms http://www.earthdoc.org/publication/publicationdetails/?publication=3058 http://www.earthdoc.org/publication/publicationdetails/?publication=3058 http://www.earthdoc.org/publication/publicationdetails/?publication=3058 http://www.earthdoc.org/publication/publicationdetails/?publication=3058 http://www.earthdoc.org/publication/publicationdetails/?publication=3058 http://www.earthdoc.org/publication/publicationdetails/?publication=3058 http://www.jgmaas.com/sca/2004/sca2004-30.pdf http://www.jgmaas.com/sca/2004/sca2004-30.pdf http://www.jgmaas.com/sca/2004/sca2004-30.pdf http://www.jgmaas.com/sca/2004/sca2004-30.pdf http://www.jgmaas.com/sca/2004/sca2004-30.pdf http://www.jgmaas.com/sca/2004/sca2004-30.pdf http://www.jgmaas.com/sca/2004/sca2004-30.pdf http://www.jgmaas.com/sca/2004/sca2004-30.pdf https://www.onepetro.org/conference-paper/spe-89516-ms https://www.onepetro.org/conference-paper/spe-89516-ms https://www.onepetro.org/conference-paper/spe-89516-ms https://www.onepetro.org/conference-paper/spe-89516-ms https://www.onepetro.org/journal-paper/spe-12016-pa https://www.onepetro.org/journal-paper/spe-12016-pa https://www.onepetro.org/journal-paper/spe-12016-pa https://www.onepetro.org/journal-paper/spe-12016-pa https://ethos.bl.uk/orderdetails.do;jsessionid=b120d98515fa3a016b999bb28eb6dff8?uin=uk.bl.ethos.271671 https://ethos.bl.uk/orderdetails.do;jsessionid=b120d98515fa3a016b999bb28eb6dff8?uin=uk.bl.ethos.271671 https://ethos.bl.uk/orderdetails.do;jsessionid=b120d98515fa3a016b999bb28eb6dff8?uin=uk.bl.ethos.271671 https://ethos.bl.uk/orderdetails.do;jsessionid=b120d98515fa3a016b999bb28eb6dff8?uin=uk.bl.ethos.271671 https://www.onepetro.org/journal-paper/spwla-2003-v44n4a4 https://www.onepetro.org/journal-paper/spwla-2003-v44n4a4 https://www.onepetro.org/journal-paper/spwla-2003-v44n4a4 https://www.onepetro.org/journal-paper/spwla-2003-v44n4a4 https://www.onepetro.org/journal-paper/spwla-2003-v44n4a4 https://www.onepetro.org/conference-paper/spe-87056-ms https://www.onepetro.org/conference-paper/spe-87056-ms https://www.onepetro.org/conference-paper/spe-87056-ms https://www.onepetro.org/conference-paper/spe-87056-ms https://www.onepetro.org/conference-paper/spe-87056-ms https://www.onepetro.org/conference-paper/spe-87056-ms s. a. lazim, et al. / iraqi journal of chemical and petroleum engineering19,3 (2018) 41-45 24 تقييم النفاذية للمكمن الكربوني )دراسة حالة/حقل جنوب العراق( الخالصة طبيعة عدم التجانسية للمكامن الكاربونية تظهر من خالل التشتت الحاد للبيانات ولذلك يجب توخي الحذر في مسمامية لحساب النفاذية مالم يكون هناك معامل ارتباط جيد متاح. -المتبادلة للنفاذية استخدام عالقة االرتباط المسامية غير كافية بحد ذاتها وذلك لكون -متبادلة للنفاذيةباالضافة الى ذلك فإن تقنية عالقة االرتباط ال دراسات المحاكاة تتطلب ايضا ادوات اكثر دقة لوصف المكمن وتشخيص الوحدات ذات الجريان وعدم الجريان. التقييم لتوصيف المكمن تم أجراؤه من خالل هذا البحث لتكوين المشرف لحقل نفطي في جنوب العراف )مكمن ( hu'sالمسامية ,طريقةالوحدات الهيدروليكية ) -غير متجانس(, وهي عالقة االرتباط بين النفاذيةكاربوني (.rqi( اباالعتماد على دليل جودة المكمن ) gheوطريقةالعناصر الهيدروليكية العالمية ) iraqi journal of chemical and petroleum engineering vol.17 no.2 (june 2016) 2535 issn: 1997-4884 radiological assessment and mechanical separation of norm contaminated soil from iraqi oil fields yousif m. zayir * , nada. s. ahmedzeki ** , takrid m. nafae *** , wssam zaidan *** , o.el samad *** and rola bou khozam *** * ministry of science and technology, baghdad, iraq, ** university of baghdad,collage of engineering, chemical engineering dept. baghdad, iraq, *** lebanese atomic energy commission, lebanon.. abstract naturally occurring radioactive materials (norm) contaminated sites at alrumaila iraqi oil fields have been characterized as a part of soil remediation project. activity of radium isotopes in contaminated soil have been determined using gamma spectrometer high purity germanium detector (hpge) and found to be very high for al-markezia, al-qurainat degassing stations and storage area at khadhir almay region. the activity concentration of samples ranges from 6474.11±563.8 bq/kg to 1232.5±60.9 bq/kg with mean value of 3853.3 bq/kg for 226 ra, 843.59±8.39 bq/kg to 302.2±9.2 bq/kg with mean value of 572.9 bq/kg for 232 th and 294.31±18.56 bq/kg to 156.64±18.1 bq/kg with mean value of 225.5 for 40 k. six hazard indexs radium equivalent, representative level index, adsorbed dose rate in air, annual effective dose equivalent, external hazard index, and internal hazard indexes were calculated to estimate the potential radiological health risk in soil and dose rate associated with it and found to be high. screening of contaminated soil was performed to evaluate the feasibility of particle size separation. the fractions obtained varied between 75 µm (200 mesh) to 300µm (48 mesh).the results show that the largest weight percent in fine particle size cut ( -75, -125+75, -250+125) µm is 73.9% and all radium isotopes are concentrated in 37.5µm particle size while small fluctuations are observed in the other particle size cuts. key words: norm, radium isotopes, radiological assessment, mechanical separation introduction radium is the heaviest alkaline earth metal belonging to group iia of the periodical table. it has 25 isotopes with mass numbers between 206 and 230, all of them are radioactive. the most abundant among the naturally occurring isotopes are 226 ra with a half-life of 1620 years from the uranium series ( 238 u), and 228 ra with a half-life of 5.8 years from thorium series ( 232 th). these two isotopes of radium are also the most radiotoxic and very significant from a radiological protection viewpoint due to their relatively presence in nature, iraqi journal of chemical and petroleum engineering university of baghdad college of engineering radiological assessment and mechanical separation of norm contaminated soil from iraqi oil fields 26 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net long half-lives, and high dose conversion factors. in the 1950s radium was identified as a pollutant of the environment, caused by uranium mining and milling in the usa. other, non-nuclear branches of industry have also been identified as significant sources of environmental pollution due to radium release as– phosphate fertilizer production, oil and gas exploitation, underground mining of different raw materials (heavy sands, coal, gold etc.).[1] naturally occurring radioactive materials (norm) containing 232 th 238 useries nuclides can be accumulated and concentrated in surface equipment and tubing in the form of sludge and scale as a consequence of chemical and physical processes associated with the oil and gas industry [2]. in addition, produced water (brine water) associated with oil is typically separated from oil and disposed of by one of these methods, like down an injection well or discharged into the environment for evaporation [3]. in some cases, produced water amount is greater than the amount of oil produced. therefore, it may be considered the largest volume of radioactive waste produced by the oil and gas industry [2]. most middle east operating companies dispose their wastes water into unlined pits and lagoons. subsequently, the projection water is drained to underground leaving radioactive precipitate within the soil that finally required remedial or treatment action in accordance with radiation protection principles. therefore, the remediation projects to take away and treat contaminated soil have been started in order to reduce the hazard to workers and public. [2,4]. in iraqi oil field ( rumaila), produced water is discharged into the environment for evaporation. uncontrolled disposal of this type of waste could lead to pollute the environmental and, therefore, finally lead to radiation exposure of workers in this field and members of the public. the goal of the present study is the assessment of the radiation exposure of the existing contamination of land areas from oil and gas industry in iraqi oil fields. radiological assessment for al-markezia and al-qurainat degassing stations and, mechanical separation are made to reduce the cost of disposal by reducing the volume of norm contaminated soil. experimental work 1mechanical separation three different soil samples from almarkezia and al-qurainat degassing stations and khadhir almay region were identified for radiological assessment. these soil samples are mixed and separated for different particle size ((+300), (-300+250), (250+125) , (-125+75), (-75)) using the test sieve shaker ( impact, sv003). the material held on each of the sieves or the fraction of each particle size was separated, collected, weighed, and percentage of each weight fraction was calculated. the analysis was also carried out regarding average size, mass fractions, and cumulative mass fraction. this step was made in laboratories of radiological and nuclear safety directorate (rnsd) / al-tuwaitha site / ministry of science and technology. 2sample preparation the sample preparation depends on type and quantity of samples under investigation. the soil samples were dried and then moved to spatial container. 100 or 200 ml of each soil sample was placed in standard plastic container then was sealed and stored for 3-4 weeks prior to measurement to permit the decay daughter 214 bi, 214 pb, yousif m. zayir, nada. s. ahmedzeki, takrid m. nafae, wssam zaidan, o.el samad and rola bou khozam -available online at: www.iasj.net ijcpe vol.17 no.2 (june 2016) 27 212 bi, 212 pb, 228 ac to establish an equilibrium with 226 ra, 228 ra and 224 ra and counting by gamma spectrometer[5]. the analytical measurements were made in the laboratories of the environmental radiation control department at the lebanese atomic energy commission (laec) in lebanon. 3measurement of sample particle size radionuclide activity concentration was analyzed using gamma spectrometer from canberra equipped with extended range low-level coaxial high purity germanium (hpge) detector with high resolution (2.1 kev at 1332 kev) and 50% relative efficiency was utilized in this study. in order to reduce the background radiation, the detector was surrounded with a 10-cm-thick lead shield and by a 0.5 cm copper layer to attenuate the xrays emitted by the lead shield. the detector was linked to standard integrated data processor dsa 1000 desktop inspector electronics from canberra and the spectra were accumulated in 8k mca. a standard multigamma radioactive source from isotope products laboratories (iso) used to the energy calibration. this was done by preparation standard sample in the same geometry as the samples to be analyzed, this step occurred once in week or when needed, the efficiency calibration is estimated. moreover, efficiency curves were corrected for attenuation and absorption. the background spectra were measured regularly under the same conditions used for the sample and applied to correct the calculated sample activities. the linearity and the resolution of the detector were checked using a standard 152 eu point source. the time counted for each sample ranged between 3 to 48 hr and spectra were analyzed offline using genie 2000 software from canberra version v3.1.a, including peak search, nuclide identification, activity and uncertainty calculation, and mda calculation modules.[5] the method allowed to determine norm nuclides as summarized in table (1) 226 ra activities was calculated at 186.2 kev after correction for 235 u [7]. if interference of the 186.2 kev photon from 235 u cannot be excluded, 226 ra activities in the samples were then measured by determining its gamma emitted daughters ( 214 pb or 214 bi) after equilibrium[6]. 228 ra was determined from the gamma line of its daughter 228 ac at (911.2 kev), as well as 224 ra was determined from gamma line of its daughter 212 pb, and 212 bi at (238.63, and 727.33) respectively because the emanation rate of the 226 ra progeny 222 rn from scales and sludges is typically very low, 226 ra may be measured directly by its γ energy 186.2 kev in all samples with low concentrations of uranium [7]. table 1, summary of gamma spectrometry on norm counting solids [2] isotope isotopes heuristics energy (kev) gamma emissions probability (%) 226 ra 226 ra 186.2 3.56 214 pb 351.93 35.6 214 bi 609.31 45.49 228 ra 228 ac 911.2 26.2 224 ra 212 pb 238.63 43.6 212 bi 727.33 6.65 radiological assessment and mechanical separation of norm contaminated soil from iraqi oil fields 28 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net the two radium isotopes identified to be of primary concern are 226 ra and 228 ra because of potential carcinogenic impact. results and discussion 1hazard assessment for soil sample it is reasonable to develop as many as possible identified radiation health hazard indices analysis to obtain effective conclusion on the human health and environment. six values have been calculated to assess the radiation health hazards associated with the soil samples as described below [8&9]. calculation of radium equivalent activity the distributions of 226 ra, 232th, and 40 k in samples are not uniform therefore, to represent their specific activities by a single quantity to take into calculation the radiation hazards related with them. to define raeq activity, it can be assumed that 1 bq/kg of 226 ra, 0.7 bq/kg of 232 th or 13 bq/kg of 40 k give the same dose of gamma ray. radium equivalent has been used as radiological index (raeq) in bq/kg which is calculated using eq. (1) [10] … (1) where : the activity concentrations of 226ra in bq/kg : the activity concentrations of 232th in bq/kg : the activity concentrations of 40k in bq/kg calculation of representative level index (iγ) the representative level index (iγ) is the second hazard index used in this study for the calculation of gamma radiation related with the natural radioactive materials in the soil. it is calculated using eq. (2). the safety value for this index is [11] … (2) calculation of air absorbed radiation dose rate gamma radiation effects are usually expressed in terms of adsorbed dose rate in air. at a height of about 1 meter above the ground surface the external terrestrial absorbed dose rate of γradiation in air was calculated for 226 ra, 232 th and 40 k radionuclides, using eq. (3). the conversion factor of 0.462 ngy h -1 /bq kg -1 for 226 ra, 0.621 ngy h -1 /bq kg -1 for 232 th, and 0.0417 ngy h -1 /bq kg -1 for 40 k, equilibrium is assumed between 226 ra and 232 th series with all their daughter and the effect of 90 sr, 137 cs, and 235 u decay series can be neglected because of their small contribution to the whole dose from background. [11] ( ) … (3) calculation of annual effective dose the annual effective dose equivalent outdoor predictable to be absorbed by the human due to the radioactivity in soil was calculated using eq. (4). to convert absorbed rate in air to effective dose using a conversion factor of 0.7 sv gy -1 , with an outdoor occupancy factor of 20 and 80% for indoor [11]. ( ⁄ ) ( ) … (4) calculation of external and internal hazard index [10] the external hazard index (hex) is widely used to reflect to external exposure and can be calculated by eq. (5): yousif m. zayir, nada. s. ahmedzeki, takrid m. nafae, wssam zaidan, o.el samad and rola bou khozam -available online at: www.iasj.net ijcpe vol.17 no.2 (june 2016) 29 … (5) and the internal hazard indexes (hin) used to reflect to internal exposure to radon and its daughter … (6) in order to keep the radiation hazard to be insignificant the value of external and internal radiation hazard index must be less than unity. the data in table (2) are summarized of measurements of natural radionuclide ( 226 ra, 232 th, and 40 k) concentration in the collected soil samples from markezia (m1and m2) and qurainat (q1) degassing station, and khidhr-almay (kh1) where mean value of samples (s7 to s11) were taken. the world average concentrations for 226 ra, 232 th, and 40 k in soil sample are 35, 30, 400 bq/kg respectively. table (2) shows that, the activity concentration of 226 ra and 232 th in selected soil of degassing station are higher than the world value reported in [10] and these concentration are more than 150 and 44 times for 226 ra and 232 th respectively. the concentration for 40 k is lower as compared with the world figures. the value of radium equivalent activity, representative level index, absorbed gamma radiation dose, annual effective dose equivalent outdoor, internal and external hazard index are shown in table (3). radium equivalent is calculated from eq. (1) values of contaminated samples range from 7593.83bq/kg (markezia ) to 1679.93bq/kg (qurainat) with mean value 4636.88 bq/kg which is higher than the safe limit (370 bq/kg) recommended by organization for economic cooperation and development (oecd)[8]. the recommended value of annual effective dose equivalent is 1 msv/year for the personal of the public and 20 msv/year for the workers in the radiation field. this is fixed by the international commission on radiological protection (icrp). from table (3) it is clear that the absorbed dose rate calculated by eq. (3) ranges from 3478.59 (markezia) to 765.36 (qurainat) ngyhr -1 with an average value of 2121.98 ngyhr -1 . the world wide average annual effective dose is approximately 0.5 msv. the annual effective dose of these samples is higher than the acceptable value except q1. the values of internal and external hazard index are higher than unity therefore, according to the report of radiation protection 112; the soil isn't safe and can't be used as a building material without any significant radiological hazard to population [9]. 2particle size distribution particle size measurement was made using sieve analysis.after sieving, each particle size cut was collected, weighted and measured. fig. 1, histogram presentation of screen analysis radiological assessment and mechanical separation of norm contaminated soil from iraqi oil fields 30 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net the results are shown in table (4) and figure (1 and 2), plotted as a histogram, and cumulative distribution. the fractional or acumulative distribution curves are made by assuming the material between two screens to have a particle diameter that is the arithmetic average of the two screen openings. table 2, the activity concentrations of 226 ra, 232 th, and 40 k in bq/kg measured in contaminated soil sample no. a.conc. of 226 ra bq/kg a.conc. of 232 th bq/kg a.conc. of 40 k bq/kg m1 6474.11±563.8 774.59±9.19 156.64±18.1 m2 4073.91±141.12 843.59±8.39 170.05±13.01 q1 1232.5±60.9 302.2±9.2 198.5±14.6 kh1 3619.4±12.9 843.3±9.9 294.31±18.56 s7-s11 5508.3±217.6 1363±69.2 315.5±24.5 table 3, calculated values of hazard assessment sample no. radium equ. activity (bq/kg) raeq representative level index (iγ) absorbed dose rate d (ngy hr -1 ) annual effective dose rate msv aede external hazard index hex internal hazard index hin m1 7593.83 51.01 3478.59 4.27 20.52 38.02 m2 5293.34 35.71 2413.11 2.96 14.30 25.31 q1 1679.93 11.37 765.36 0.94 4.54 7.87 kh1 4847.98 32.76 2208.12 2.71 13.10 22.88 s7-s11 7481.95 50.56 3404.52 4.18 20.22 35.10 fig. 2, cumulative distribution curve the results were obtained for five fractions with different mesh size and their weight percent in the samples. the fractions obtained varied between 75 µm (200 mesh) to 300µm (48 mesh). figures above show that the largest weight percent in fine particle size ( -75, -125+75, -250+125) µm is 73.9% . the average diameter d50 was determined from fig(2) and was equal to112 µm. the surface mean diameter of soil samples was calculated from eq. (7) and found to be equal to 48 µm. this value ensures the high contribution of the fines in the soil sample, considering the surface mean in the calculations. yousif m. zayir, nada. s. ahmedzeki, takrid m. nafae, wssam zaidan, o.el samad and rola bou khozam -available online at: www.iasj.net ijcpe vol.17 no.2 (june 2016) 31 √ ∑ ∑ ( ) … (7) radioactivity distribution with soil particle size each particle size soil sample was analyzed for the exposure dose rates by portable instrument to select the dealing method. the results are presented in table (5). it can be seen that high values of exposure rate for all samples are observed, and greater than three times of the background (bg) value, therefore, personal protection equipment was used. furthermore the work area was carefully prepared to reduce the contamination of the area and equipments table 4, results of typical screen analysis sample no. mesh no. particle size µm mean particle size dp (µm) weight of sample (g) weight % cumulative s1 -200 -75 37.5 544.8 22.8 0.228266 s2 -115 + 200 -125 +75 100 543 22.8 0.455778 s3 60 + 115 -250 +125 187.5 676.6 28.3 0.739267 s4 48 + 60 -300 +250 275 228 9.6 0.834796 s5 48 300 300 394.29 16.5 1 table 5, exposure rate measurement for soil samples sample no. particle size µm mean particle size µm exposure rate nsv/hr s1 -75 37.5 677 s2 -125 +75 100 397 s3 -250 +125 187.5 313 s4 -300 +250 275 225 s5 300 300 393 bg 60 table 6, activity concentrations for radium isotopes and potassium of contaminated soil for particle size distribution sample no. a.conc. of 226 ra bq/kg a.conc. of 228 ra bq/kg a.conc. of 224 ra bq/kg a.conc. of 40 k bq/kg 186.2 kev 351.93 kev 609.31 kev 911.2 kev 238.63 kev 727.33 kev 1460 kev s1 14520±279.2 13290±222.8 12850±211 3367±116.5 3935±81.7 4545±75.4 245.5±9 s2 5759±119.2 5398±91.4 5202±86.5 1549±55 1751±36.9 1984±43.6 339.8±20.7 s3 5160±208.9 4694±188.1 4330±174.2 1234±62.2 1503±62.6 1623±66.3 332.8±17.7 s4 7038±289.9 6267±251.5 5714±230.4 1672±85.5 2072±86.6 2336±101 240.9±39 s5 7669±313 6903±276.8 6344±255.5 2007±101.7 2407±100.4 2596±108.7 223±43 radiological assessment and mechanical separation of norm contaminated soil from iraqi oil fields 32 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net after that all these samples were measured by gamma spectrometer techniqe and the results are shown in table (6). 226 ra, 228 ra, and 224 ra activities were determined in different particle size soil samples from the contaminated area in al-rumaila oil field. the results of samples are presented in table (6) and fig. (3, 4, and 5). it was observed that all radium isotopes are concentrated in 37.5µm particle size and small fluctuations in other particle size. furthermore, the activity concentrations of radium isotopes ( 226 ra, 228 ra, and 224 ra) with small particle size is higher than the activity concentration with large particles. for that, determination of radium isotopes distribution with particle size is more important for volume reduction of radioactive waste [12]. fig. 3, particle size distribution with activity concentrations for 226 ra fig. 4), particle size distribution with activity concentrations for 228 ra fig. 5, particle size distribution with activity concentrations for 224 ra 3evaluation of the homogeneity of the contaminated soil to insure that all contaminated soil was completely homogenized the five random samples were taken, as shown in fig. (6). fig. 6, scheme for the preparation and homogeneity test the analytical results of the homogenized contaminated soil sample of 226 ra, 228 ra, 224 ra, and 40 k are shown in table (7) & figure (7, 8, 9 and 10). the mean value for 226 ra , 228 ra , 224 ra , and 40 k are 6088, 1363.4, 1785.8, and 315.46 bq/kg with standard deviation as 138.51, 18.28, 30.69, and 32.6 respectively. the results show that the higher standard deviation occurs for 40 k while the standard deviation for 226 ra, 228 ra, 224 ra is approximately the same for that the aggregate may be regarded as yousif m. zayir, nada. s. ahmedzeki, takrid m. nafae, wssam zaidan, o.el samad and rola bou khozam -available online at: www.iasj.net ijcpe vol.17 no.2 (june 2016) 33 homogenous because all values were distributed on the mean values. fig. 7, representation of homogeneity test results for 226 ra concentration in contaminated soil fig. 8, representation of homogeneity test results for 228 ra concentration in contaminated soil fig. 9, representation of homogeneity test results for 224 ra concentration in contaminated soil fig. 10, representation of homogeneity test results for 40 k concentration in contaminated soil table 7, activity concentration for radium isotopes and potassium in homogenized contaminated soil sample no. a.conc. of 226 ra bq/kg a. conc. of 228 ra bq/kg a.conc. of 224 ra bq/kg a.conc. of 40 k bq/kg 186.2 kev 351.93 kev 609.31 kev 911.2 kev 238.63 kev 727.33 kev 1460 kev s7 5875±244.3 5213±209.9 4918±198.6 1341±69.2 1655±69.3 1885±84.5 322.3±24.5 s8 6247±253.1 5562±222.8 5110±205.6 1391±70.2 1721±71.7 1864±76.5 322.7±16.5 s9 6141±257.6 5493±220.9 5087±205.7 1368±71.2 1722±72.3 1916±88.7 362.9±29 s10 6048±253.7 5362±215.7 4926±199.2 1360±70.7 1668±70.1 1815±84.6 286.9±25.9 s11 6129±253.8 5488±220.4 5021±202.6 1357±69.8 1713±71.7 1899±84.2 282.5±22.6 radiological assessment and mechanical separation of norm contaminated soil from iraqi oil fields 34 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net conclusions 1the activity concentrations of radium isotopes ( 226 ra, 228 ra, and 224 ra) with small particle size are higher than the activity concentration with large particles. 2the activity concentration of 226 ra and 232 th in selected soil of degassing station are higher than the world value reported in [10] and these concentrations are more than 150 and 44 times for 226 ra and 232 th respectively. while the concentration for 40 k is lower as compared with the world figures. 3the largest weight percent in fine particle size ( -75, -125+75, 250+125) µm is 73.9% . nomenclature aede annual effective dose rate the activities concentration of 226ra the activities concentration of 232th d absorbed dose rate of γ-radiation in air d50 mean particle diameter hex the external hazard index hin the internal hazard indexes iγ the representative level index a.conc activity concentrations iaea international atomic energy agency kh1 soil sample from khidhr-almay region m1,m2 soil samples from markezia degassing station mca multi channel analyzer most ministry of science and technology norm naturally occurring radioactive materials q1 soil sample from qurainat degassing station s1,s2,,s11 soil samples references 1iaea international atomic energy agency, 1990. "the environmental behaviour of radium". technical reports series no. 310, volume 1. 2iaea international atomic energy agency, 2003. "extent of environmental contamination by naturally occurring radioactive material (norm) and technological options for mitigation". technical reports series no. 419, vienna. 3mohammad saied al-masri, abdulaziz aba, 2007. "first proficiency test for the determination of norm in contaminated soil from the oil field". accred qual assur 12, 249256. 4othman i., al-masri m.s., 2004. disposal strategy for norm waste generated by the syrian oil industry. a paper presented at the international symposium on the disposal of low activity waste. 1317 december 2004, cordoba, spain. 5samad o. el., m. aoun, b. nsouli, g. khalaf, m. hamze, 2014. “investigation of the radiological impact on the coastal environment surrounding a fertilizer plant". journal of environmental radioactivity, vol. 133, pp. 69-74. 6ogp international association of oil& gas producers. 2008. "guidelines for the management of naturally occurring radioactive material (norm) in the oil & gas industry". ogp, report no.412. 7ebaid y.y., 2010. "use of gammaray spectrometry for uranium isotopic analysis in environmental samples" rom. journ. phys., v 55, nos. 1-2, p. 69-74, bucharest. 8rahman s.u., matiullah, malik f., rafique m., anwar j., ziafat m., jabbar a., 2011. "measurement of naturally occurring/fallout radioactive elements and assessment of annual effective dose in soil yousif m. zayir, nada. s. ahmedzeki, takrid m. nafae, wssam zaidan, o.el samad and rola bou khozam -available online at: www.iasj.net ijcpe vol.17 no.2 (june 2016) 35 samples collected from four districts of the punjab province, pakistan". j. radioanal nucl. chem., v 287, p 647-655. 9rohit m., surinder s., kulwant s., rajendra s., 2007. " 226 ra, 232 th and 40 k analysis in soil samples from some areas of malwa resion, punjab, india using gamma ray spectrometry". environ monit asses. v 134, p 333-342. 10unscear [2000]. sources and effects of ionizing radiation. united nations scientific committee on the effect of atomic radiation. new york: united nations. 11unscear [1993]. sources and effects of ionizing radiation. united nations scientific committee on the effect of atomic radiation. new york: united nations. 12othman i., al-masri m.s., 2002. characterization of norm contaminated sites at the syrian oil-field: sampling, analysis and data management. conference, february 24-28. iraqi journal of chemical and petroleum engineering vol.17 no.1 (march 2016) 99108 issn: 1997-4884 study in kinetics of saponification reaction of diethyl adipate with sodium hydroxide solution under reactive distillation raghad fareed kasim* and rouaa ali shokorr** college of engineering-university of baghdad *email:rfkalm@yahoo.com ** email:hu.iraq91@gmail.com abstract this research presents a new study in kinetics under reactive distillation by using consecutive two – step reaction : the saponification reaction of diethyl adipate with sodium hydroxide solution . the distillation process takes the role of withdrawing the intermediate product (sodium monoethyladipate sma) which otherwise converts to the final product of low purity.the effect of three parameters were studied through a design of experiments applying 2 3 factorial design. these parameters were : the mole ratio of da to naoh solution (0.1 and 1) , naoh solution concentration (3 n and 8 n) , and batch time (1.5 hr. and 3.5 hr.) . the conversion of da to sodium monoethyladipate(sma)(intermediate product) was the effect of these parameters which was detected .the results showed that increasing mole ratio of da to naohsolution increases the conversionto a maximum value within the range of study.the effect of naoh solution concentration decreases the conversion to a specified value within the range of study . the effect of batch time on conversion was decreasing the conversion to a specified value within the range of study . the maximum attainable conversion within the studied range of parameters was eighteen fold of thebase case.reaction rate constant k and the order of reaction n of first reaction weredetrminedusing the differential method . the study attempted to determine n and k under the maximum conversion condition obtained in this system which corresponds to : feed mole ratio of diethyl adipateda to naoh solution of 0.3,naoh solution concentration of3 nandtime of1.5 hr.the study showed that the reaction order was 1.5and reaction rate constant was 0.8m 3 /kmol.s at a temperature of 100 key words: reactive distillation, kinetic study, consecutive reaction, saponification reaction. introduction separation is one of the most significant processes in chemical engineering. from ancient times to recent days, separation processes have been implemented in almost every chemical process. the distillation process is the most suitable separation process in the chemical and petroleum industries. reactors are also essential parts of any chemical industry. reactor effluents do not usually meet the iraqi journal of chemical and petroleum engineering university of baghdad college of engineering study in kinetics of saponification reaction of diethyl adipate with sodium hydroxide solution under reactive distillation 100 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net specification criteria due to the process of the unconverted materials. therefore, it is quite common in industry to see reactors followed by a separation section with recycles. from this point of view, it is important to study and investigate the reactor / separation / recycle system. one aspect of studying this system is the reactor combined with the separation unit. this is referred to as reactive distillation [1]. it involves simultaneous chemical reaction and distillation [2]. rd has been used in industry from many decades, but its area of application has grown essentially in the past decade [3]. there are many documented success references involving the industrial implementations of rd. the implementations of rd in the petroleum and chemical industries have been increased quickly in the past decade. one such example is the production of methyl acetate by the eastman plant. in this case a single rd column replaced the conventional flow sheet consisting of eleven major operation units with an assortment of pumps, heat exchangers, and controllers. the result was a fivedoubles reduction in energy consumption and capital investment over the conventional design for methyl acetate production [4]. for esterification reactions: when carboxylic acid treated with an alcohol, an ester is formed. saponification reaction is a kind of esterification reaction that can be conducted under reactive distillation (rd). the general utility of rd is increasing the conversion of reversible reactions [5]. rd depends on the withdrawal of the product (or one of the products) by evaporation from the reacting mixture. this technique accelerates the forward reaction .in previous research of the investigators [6], it was shown that the maximum conversion obtained for this system was 18.58fold of that for the base case (the base case is the experiment that carried out at lower values of all the parameters, which is regarded as base or reference case). the maximum conversion value corresponded to the set of parameters (under study): feed mole ratio of da to naoh solution (x1) = 0.3, naohsolution concentration (x2) = 3 n, and distillation time (x3) = 1.5 h. newberger and kadlec [7], studied the kinetic of saponification reaction of diethyl adipate with sodium hydroxide solution in a batch isothermal system at temperature of 293.1 k. they determined reaction order and reaction rate constant for the two consecutive reactions which can be represented as follows: (ch2)4(cooc2h5)2+naoh ⇒(ch2)4(c oona)(coo c2h5) + c2h5oh ... (1) (ch2)4(coona)(cooc2h5)+naoh ⇒ (ch2)4(coo na)2 + c2h5oh ... (2) they found that the rate constant of the first reaction (k1) to be 9.3 m 3 / kmole . s , while that of the second reaction (k2) to be 7.7 m 3 / kmole . s . these values were obtained at temperature 293.1 k . it is obvious that k1> k2 i.e. the first reaction is faster than the second. they also found that the frequency factors of arrhenius equation , and the activation energies of the two reactions were: a1 = 4.87 * 10 6 m 3 / kmole . s a2 = 3.49 * 10 6 m 3 / kmole . s e1 = 42.2 kj / mole e2 = 25.0 kj / mole it is obvious that e1> e2 , so the first reaction has a higher energy barrier than the second reaction. raghad fareed kasim and rouaa ali shokorr -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 101 in addition , they determined the heats of the two reactions to be: δh1 = 45.2 ± 3.4 kj / mole δh2 = 68.0 ± 4.2 kj / mole these quantities were found to contribute at most 0.5 k in temperature rising in tubular reactor which they used. table 1, the reaction order and reaction rate constant values for diethyl adipate with sodium hydroxide solution at (293.1 k) temperature [8] investig-ator ca kmol. /m 3 cb kmol. /m 3 reaction order k1 , m 3 / kmol.s k2 , m 3 / kmol.s ingold (1931) 0.002 0.002 2 3.52 0.704 westhe-imer (1942) 0.01 0.01 2 5.20 1.83 westhe-imer (1942) 0.005 –0.011 0.005–0.011 2 5.7 – 6.1 ---- frost and schwe-mer (1952) 0.01 0.01 – 0.02 2 ----1.7 – 2.2 newber-ger and kadlec (1973) 0.02 0.05 2 9.3 7.7 they also compared their results with some former ones that were published as given in table (1). the reaction system can be represented by: a + b c + d c + b e + d where: a: refers to diethyl adipate (da) b: refers to sodium hydroxide solution c: refers to sodium monoethy ladipate (sma) d: refers to ethanol e: refers to disodium adipate (dsa) from eq. (1), the kinetic study of the first reaction depended on measuring sma concentration (i.e. cc). rc = = k ca cb … (3) eq. (3) represents the rate equation. in order to apply the differential method ra must be determined. from eq. (4) we see that rc can be converted to ra. = … (4) as the stoichiometric number of c and a is the same, therefore; -ra=rc numerically. so ra can be determined directly from calculating rc as shown later. experimental work 1materials diethyl adipate, sodium hydroxide pellets. hydrochloric acid hcl ,borax , methyl red , methyl orange for sodium hydroxide solution standardisation. study in kinetics of saponification reaction of diethyl adipate with sodium hydroxide solution under reactive distillation 102 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net 2procedure 1according to the design of experiment table (2) ,(montgomery[9]) three factors were intended to study (feed mole ratio , sodium hydroxide (naoh) solution concentration, and batch "distillation" time) within the ranges set in the table(3). 2sodium hydroxide (naoh) solution with (3n concentration), was prepared and standardized using indicators, (vogel [10]) and phmeter. 3measured amounts (12 – 129 ml.) of diethyl adipate (da) and sodium hydroxide "naoh" solution (31 – 332 ml.) was mixed in (500 – ml.) distillation flask which was shielded. 4heating the mixture till boiling. the distillate began to appear at approximately about 100 0 c. 5the distillate was collected in receiving conical flask. it was noticed that it was composed of two layers. 6the distillate was transferred to a (500 ml.) separating funnel. 7the weight and volume of each layer were measured. 8relative conversions were also determined for the center values of the parameters shown in table (3).additional experiments were performed to get sufficient data for plotting. 3test method ftir measurement was done for each layer which showed that sodium monoethyladipate (sma) appeared in the dominate upper layer. the unreacted diethyl adipate (da) appeared in the impaired lower layer. atomic absorption was made for the upper layer to measure the concentration of sma (cc)as given in table (4). table 2, design of experiments time(x3), (hr) naoh solution concentration (x2) , (n) feed mole ratio (x1) , (mol. da / mol. naoh) 1.5 3 0.1 1.5 3 1 1.5 8 0.1 1.5 8 1 3.5 3 0.1 3.5 3 1 3.5 8 0.1 3.5 8 1 table 3, ranges of parameters studied factor low value (-) centre value (0) high value (+) feed mole ratio (x1) , (mole da / mole naoh solution) 0.1 0.55 1 naoh solution concentration (x2) , (n) 3 5.5 8 time (x3) , (h) 1.5 2.5 3.5 results and discussion from sma concentration, relative conversion (conversion of da to sma relative to base case conversion) was calculated. the variation of relative conversion with feed mole ratio x1 were drawn for naoh solution concentration x2 = 3 n , and different batch time x3 = 1.5 and 3.5 h as shown in fig. (1).from this figure , it is obvious that for the two curves the relative conversion proportionally increased with increasing feed mole ratio in the range x1 = (0.1 0.3) . the two curves have a maximum relative conversion at x1 = 0.3 which seems to be the best value in our range of feed mole ratios. after that increasing, feed mole ratio in the rangex1 = (0.3 – 1) decreased relative conversion. the increasing in relative conversion with increasing feed mole ratio in the rangex1 = (0.1 – 0.3) was because of the increasing in sma concentration in this range of feed mole ratios. raghad fareed kasim and rouaa ali shokorr -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 103 the decreasing in relative conversion for the rangex1 = (0.3 – 1) was due to the decreasing in sma concentration. this can be explained as follows: the rate of first conversion reaction (sma production) is higher than the rate of second conversion reaction (sma consumption), newberger and kadlec [7]. the increasing in feed mole ratio in the range (x1 = 0.1 – 0.3) activated the first conversion reaction (i.e sma production increased) and its concentration in distillate increased. higher increasing in feed mole ratio in the range (x1 = 0.3 – 1) activated the second conversion reaction (i.e. sma consumption increased) so its concentration in distillate decreased. also, it is clear from this figure that the relative conversion for the curve of shorter distillation time (t = 1.5 hr.) at (x1 = 0.15 – about 0.8) was higher than that of longer distillation time (t = 3.5 hr.). at (x1 = 0.3) relative conversion for the curve of shorter distillation time was (18.58), while for the curve of longer distillation time was (9.76). fig. 2 also explains the variation of relative conversion with feed mole ratio (x1) and different batch time (x3 = 1.5 and 3.5 hr.). the two curves were drawn for the same naoh solution concentration (x2 = 8 n). from this figure, it is clear that for the curve of shorter distillation time, relative conversion increased with feed mole ratios in the range (x1 = 0.1 0.3). the curve has a maximum value of relative conversion (2.76) at (x1 = 0.3). after that the relative conversion decreased when feed mole ratio increased in the range (x1 = 0.3 – 1). the peak of the curve of shorter distillation time (2.76) is lower than the corresponding one of fig. 1.this is because of lower weight of distillate upper layer and higher volume of da .relative conversion is a function of sma concentration, weight of distillate upper layer, and da volume as shown in eq. (5): relativeconv.= ( ) ... (5) for the curve of longer distillation time it is clear that the relative conversion decreased when feed mole ratio increased in the range (x1 = 0.1 0.55). the curve has a minimum value of relative conversion (0.18) at (x1 = 0.55). then relative conversion increased somewhat till (x1 = 1). the decreasing in relative conversion with feed mole ratio in the range (x1 = 0.1 – 0.55) because of decreasing in weight of distillate upper layer and increasing in da volume. the increasing in relative conversion in the range (x1 = 0.55 1) was because of increasing in weight of upper layer distillate and increasing sma concentration. the peak of the curve of longer distillation time (0.62) is lower than the corresponding one of fig. 1.this is because of lower weight of distillate upper layer and higher volume of da as mentioned above. fig. 3 shows the variation of relative conversion with naoh solution concentration (x2). the curve was drawn for feed mole ratio (x1 = 0.3) and batch time (x3 = 2.5 hr.). from this figure, it is clear that the relative conversion decreased with increasing naoh solution concentration in the range (x2 = 3 – 5.5 n) . the curve has a minimum value of relative conversion (0.39) at (x2 = 5.5 n) . after that the relative conversion increased when naoh solution concentration increased in the range (x2 = 5.5 – 8 n) . the behaviour of this curve was due to the decreasing then increasing of sma concentration with naoh solution concentration. study in kinetics of saponification reaction of diethyl adipate with sodium hydroxide solution under reactive distillation 104 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net fig. 4 explains the variation of relative conversion with distillation time (x3). the curve was drawn for feed mole ratio (x1 = 0.3) and naoh solution concentration (x2 = 3 n). from this figure, it is clear that the relative conversion decreased when distillation time increased in the range (t = 1.5 – 2.5 hr.). the curve has a minimum value of relative conversion (0.68) at (t = 2.5 hr.) . after that, the relative conversion increased with increasing distillation time in the range (t = 2.5 – 3.5 hr.). this behaviour is due to the decreasing then increasing of sma concentration with distillation time. fig. 5 also explains the variation of relative conversion with distillation time (x3), and feed mole ratio (x1 = 0.3). the curve was drawn for naoh solution concentration (x2 = 8n). from this figure, it is clear that the relative conversion decreased with increasing distillation time. this can be attributed to the decreasing in sma concentration as discussed before. fig. 1, relative conversion vs. feed mole ratio (x1) for naoh sol. conc. = 3 n and t = (1.5 & 3.5 hr.). fig. 2, relative conversion vs. feed mole ratio (x1) for naoh sol. conc. = 8 n and t = (1.5 & 3.5 hr.). fig. 3, relative conversion vs. naoh solution concentration (x2), (n) for feed mole ratio = 0.3 and t = 2.5 hr. raghad fareed kasim and rouaa ali shokorr -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 105 fig. 4, relative conversion vs. t (x3), (hr.) for feed mole ratio = 0.3 and naoh sol. conc. = 3 n. fig. 5, relative conversion vs. t (x3), (hr.) for feed mole ratio = 0.3 and naoh sol. conc. = 8n. table 4, shows sma concentration in distillate upper layer with distillation time for the maximum conversion set of parameters (i.e. feed mole ratio = 0.3 and naoh sol. conc. = 3 n). t , hr. cc , ppm. 0 0 1.5 106.10 2.5 10.55 3.5 50.31 fig. 6, sma concentration in distillate (ppm.) versus time(hr.) for feed mole ratio=0.3 and naohsol. conc. =3n . table 5, shows values of diethyl adipate concentration (limiting reactant) (ca), and reaction rate (-ra) with their logarithms. cc , ppm ca , ppm log ca -ra= dcc/dt = rc log -ra 0 0 ------------ 2.01 2.07 0.32 4.14 0.62 4 4.13 0.62 4.51 0.65 106.10 109.48 ------------ 10.55 10.89 1.04 56 1.75 50.31 51.91 1.72 100 2 study in kinetics of saponification reaction of diethyl adipate with sodium hydroxide solution under reactive distillation 106 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net fig. 7, plot of log(-ra) vs log(ca) for determining reaction order (n) and rate constant (k). sma concentration (cc) versus batch time (t) data was plotted as shown in fig. (6) .the slopes of the curve at different values of cc were determined .these slopes represented the rate of reaction rc which are listed in table (5).from eq. (6) diethyl adipate concentration (ca) was calculated from sodium monoethyladipate concentration (cc). ca=cc* ( ) ( ) ... (6) the results are shown in table (5). also in table (5) the logarithms of these values were obtained. fig, (7) shows a plot of log(-ra) versus log ca. a linear relation was obtained. the slope of this relationship represents n (order of reaction) and the intercept representslog (k) levenspiel [11]. from eq. (7) and eq. (8) the resulting values of n and k are 1.5 and 0.8 m 3 /kmole. s respectively. … (7) log k = -0.1 k=0.8 m 3 /kmole.s … (8) reaction rate constant (k) for saponification of diethyl adipate as calculated by newberger and kadlec (1973) was (9.3 m 3 /kmole.s) at temperature of (293.1 k) and initial concentrations of da and naoh solution of (0.02 and 0.05) respectively as given in table (1). in this study reaction rate constant was (0.8 m3/kmole.s) at temperature about (100 ) (the distillation temperature). this was in fair agreement with arrhenius equation eq. [9] which shows that the rate constant is inversely proportional with temperature. k = aexp( ) ... (9) or in logarithmic form: ( ) ( ) ( ) it is obvious that: ( ) so increasing temperature till boiling is essential to achieve reactive distillate, but this technique will retard the magnitude of the reaction rate (k) for this reaction . this issue is a matter of balancing between the rate of reaction and gaining of a valuable intermediate product. conclusions from this study the following items can be concluded: 1feed mole ratio x1 obviously affected the concentration of sma in the distillate. accordingly the conversion was influenced by it. increasing feed mole ratio caused increasing in the concentration of sma, and conversion of da to sma in the range (0.1 0.3) , when the other factors x2 (naoh solution concentration) and x3 (batch time) were fixed at specified values . in the range (0.3 –1)of x1 the raghad fareed kasim and rouaa ali shokorr -available online at: www.iasj.net ijcpe vol.17 no.1 (march 2016) 107 concentration , and conversion decreased. 2increasing sodium hydroxide solution concentration x2 increased the conversion with other parameters x1 and x3 fixed. that was attributed to the effect of naoh as a reactant which accelerated the reactions with increasing in its concentration. although, there were some ranges x2 = (3 – 5.5 n) of naoh solution concentration which caused decreasing in sma concentration, and conversion. 3the conversion of da to sma for x1 = 0.3 and x2 = 3 n showed decreasing with increasing batch time x3 till x3 = 2.5 h . then the conversion increased with increasing x3. 4the conversion of da to sma for x1 = 0.3 and x2 = 8 n showed decreasing with increasing batch time x3. 5the maximum conversion obtained in this study was 18.58 fold of that for the base case.the maximum conversion corresponds to the set of parameters (x1 = 0.3, x2 = 3 nandx3 = 1.5 h). 6the order of reaction and reaction rate constant at maximum conversion set of parameters were 1.5 and 0.8m 3 /kmole.s, respectively. 7reaction rate constant determined in reactive distillation system is of lower value than that with ordinary operated system. this affirms arrhenius equation outputs. abbreviation rd= reactive distillation da= diethyl adipate sma= sodium monoethyladipate dsa= di-sodium adipate nomenclature a= pre-exponential (frequency) factor (m 3 /kmole.s) r= perfect gas law constant (j/mole.k) e= activation energy (kj/mole) ca= concentration of da (kmole/m 3 ) cb= concentration of naoh soln. (kmole/m 3 ) references 1al – arfaj , m. , " quantitative heuristic design of reactive distillation " , chemical department , college of engineering , university of lehigh , 1999 . 2lone , s. r. , and ahmad , s. a. , "modelling and simulation of ethyl acetate reactive distillation using aspen plus" , international journal of scientific & engineering research , vol. 3 , no. 8 , pp. (1 – 5) , 2012 . 3al – arfaj , m. , and luyben , w. l. , "comparison of alternative control structures for an ideal two –product reactive distillation column " , industrial chemical engineering research , vol. 39 , no. 9 , pp. (3298 – 3307) , 2000 . 4munshi , b. , and kumar , s. , " modelling and simulation of ethyl acetate reactive distillation column using aspen plus " , thesis , chemical department , college of engineering , university of technology, iraq , 2010. 5luyben , w. l. , and yu ,c. , (2008) , " reactive distillation design and control " , wiley , united states of america , 1-574. 6kasim , r. f. , and shokorr , r. a. , (2015) , " semibatch reactive distillation of consecutive reaction :the saponification of diethyl adipate with sodium hydroxide solution " , baghdad university, chemical engineering , 1-133. study in kinetics of saponification reaction of diethyl adipate with sodium hydroxide solution under reactive distillation 108 ijcpe vol.17 no.1 (march 2016) -available online at: www.iasj.net 7newberger , m. r. , and kadlec , r. h. , (1973) , " kinetics of the saponification of diethyl adipate " , aiche journal , no. 6 , vol. 19 , 1272 – 1275. 8ingold , c. k. , (1973) " the mechanism and constitutional factorscontrolling the hydrolysis of carboxylic esters " , westheimer , f. h. , w. a. jones , and r. a. lad , " electrostatic influence of substituents on reactor rates " , frost , a. a. , and w. c. schweimer , " the kinetics of competitive consecutive second order reactions – the saponification of ethyl adipate and ethyl succinate " , cited in newberger , m. r. , and kadlec , r. h. , " kinetics of the saponification of diethyl adipate " , aiche journal , no. 6 , vol. 19 , 1272 – 1275. 9montgomery, d. c., 2001, designandanalysisofexpe riments, 5 th ed., john wiley &sons (asia) pte. ltd., singapor. 10vogel , a. i. , (1961) , "quantitative inorganic analysis including elementary instrumental analysis " , longmans , green and co ltd 48 grosvenor street , 3 rd ed. , london , 1-1216 . 11levenspiel, o., (1999), “chemical reaction engineering”, john wiley & sons, united states of america, 3 rd ed., 1-668. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.21 no.3 (september 2020) 39 – 44 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: manal adnan mohammed, email: manaladnan24@yahoo.com , name: wasan omar noori, email: wassanmch234@yahoo.com , name: huda adil sabbar, email: enghudaadil@gmail.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. application of emulsion liquid membrane process for cationic dye extraction manal adnan mohammed a , wasan omar noori a and huda adil sabbar b a chemical engineering department-university of baghdad b al-khwarizmi engineering college -university of baghdad abstract in the present work studies were carried out to extract a cationic dye (methylene blue mb) from an aqueous solution using emulsion liquid membrane process (elm). the organic phase (membrane phase) consists of span 80 as emulsifier, sulfuric acid solution as stripping agent and hexane as diluent. in this study, important factors influencing the extraction of methylene blue dye were studied. these factors include h2so4 concentration in the stripping phase, agitation speed in the dye permeation stage, initial dye concentration and diluent type. more than (98%) of methylene blue dye was extracted at the following conditions: h2so4 concentration (1.25) m, agitation speed (200) rpm, dye concentration (10) ppm and the diluent type was hexane. keywords: dye extraction, methylene blue (mb), cationic dye, emulsion liquid membrane. received on 30/12/2019, accepted on 02/04/2020, published on 30/09/2020 https://doi.org/10.31699/ijcpe.2020.3.5 1introduction discharging dyes within effluents of textile industries and other waste water is one of the major environmental problems [1, 2]. dyes are commonly utilized in many industries such as paper and ink industries, textiles, cosmetics, dyeing & printing, leather, and plastics, used for coloring their final products [1]. dyes are very toxic, carcinogenetic, risk to aquatic living organisms irritating to the skin; therefore, dyes are dangerous to human beings as well as environment [3]. water properties are seriously affected by presence of colors [2]. a present of a little amount of dyes (less than 1ppm for some dyes) in water can be undesirable and highly visible [3]. there are many types of dyes [4]:  anionic dyes (acidic) which are water soluble dyes, containing one or more sulfonic acid substituents or other acidic groups.  cationic dyes (basic) which give brilliant colors with special fastness for acrylic fibers.  direct dyes which are water soluble because of sulfonic acid groups and can be used on linen, cotton, wool, rayon, nylon and silk.  reactive dye which the colour has a very long life because of the chemical reaction; silk cotton and wool can be dyed with this type of dyeing of fabrics.  dispersive dyes which are insoluble in water a cationic dye (methylene blue) is a heavily used by printing industry. it is used also as an indicator and stabilizer in chemical industry. many ways have been implemented to remove dyes from wastewater including as physical treatment (sedimentation, crystallization, gravity separation) or conventional treatment methods (solvent extraction, reverse osmosis, ion exchange, electro dialysis, electrolysis and adsorption) [5-8]. removal of dyes by conventional treatment techniques can be difficult because of its resistant to aerobic biooxidation and the stability of dyes against light and oxidize agent [5]. in last year's several physico-chemical decolorization processes have been improved in term of affined pollutions removal, such as electrochemical, membrane separation and flocculation [6]. membrane technology has emerged as an alternative cost-effective, simple and safe method for dyes recovery and color removal from textile effluent [7]. in liquid membranes (lm) process a solute (solid species dissolve in the liquid membrane) transfer from a feed phase to stripping phase through an immiscible organic phase [9, 10]. liquid membranes process has gained a crucial role for separation in different applications, such as biomedicine, ion selective electrodes, effluent treatment and hydrometallurgy [11]. lm have many advantages compared to other membrane methods such as high selectivity, efficient, high fluxes, high potential for removal cationic and anionic dyes [12-14]. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:manaladnan24@yahoo.com mailto:wassanmch234@yahoo.com mailto:enghudaadil@gmail.com http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2020.3.5 m. a. mohammed et al. / iraqi journal of chemical and petroleum engineering 21,3 (2020) 39 44 40 according to configuration definition, lm is an effective technique for treating waste water contaminated with cationic and anionic dyes [9]. lm can be classified as emulsion liquid membrane (elm), and supported liquid membrane (slm) and bulk liquid membrane (blm) [15, 16]. in emulsion liquid membrane (elm), the membrane phase consists of (surfactant and diluent); a surfactant which is used to stabilize the emulsion and an organic diluent has low viscosity [17]. there are many advantages arising from using (elm) technique such as, simplicity, high selectivity, rapid extraction, low energy, further, its high efficiency also this method is providing high interfacial area and the ability to remove a very low concentration of the solute among the existing methods. however, elm shows some disadvantages which limited the commercial application of it such as instability of emulsions and the difficulty of demulsification after extraction [18-20]. emulsion liquid membrane system has many variables; so that in this present work some variables were chosen to be constant depending on previous experiments and researches, these variables are: volume ratio of organic phase to stripping phase = 3:1, emulsification time = 40 sec (because more than this time the w/o emulsion would be difficult to permeate the feed phase and then cannot extract mb dye), surfactant (span 80) concentration 3% and agitation time = 3 min. 2materials and equipment 2.1. materials normal hexane (supplied by chem.-lab nv, purity 95%, belgium) was used as diluent; also heptane (supplied by b.d.h laboratory reagent, purity 98%, england) and kerosene (supplied by midland iraqi refineries company) were used for some experiments. sorbitan monooleate which is commercially known as (span 80) (supplied by wuhan kemi-works chemical co., ltd) was used as a surfactant for emulsion stabiliser. sulfuric acid (h2so4) was used in the stripping phase as a stripping agent. methylene blue (mb) (supplied by himedia, purity 80%, india) was used as a cationic dye. to prepare all aqueous solutions deionised water was used. all the chemicals were used as received without further purification. the chemical structure of the methylene blue (c16h18n3scl) is given in fig. 1 by dissolving accurately weighted of mb dye in distilled water the dye solution was prepared. fig. 1. the structure of methylene blue (mb) [21] 2.2. equipment equipment was needed to experiments elm such as high speed homogenizer mixer for emulsion preparation (ultra-turrax janke & kunkel kg) and (heidolph) rzr 2020 over head stirrer was used for extraction experiments. the absorbance of dye sample was determined using uv visible spectrophotometer (thermo genesys 10 uv electron corporation madison w1 53711, usa) was used for absorbance measure. 3methodology 3.1. calibration curve methylene blue was detected in the solutions using uvvisible spectrophotometer at 664 nm wavelength. to measure any unknown concentration of samples, calibration curve was made by prepared various mb concentrations 5, 6, 7,8,9,10,11 and 12 ppm. we get the plot showed in fig. 2 from the uv results with absorbance (in y-axis) versus concentration of mb (in xaxis). fig. 2. calibration curve of mb absorption 3.2. experimental work the experimental work consists of three stages. first stage: the emulsion was prepared by adding sulfuric acid (with a various concentrations) to organic phase in a beaker of 200 ml volume by using high speed mixer (homogenizer) at a constant rotational speed 10000 rpm for 40 second. second stage: (dye permeation stage) by adding the emulsion which prepared in the first stage into a beaker of 1000 ml volume containing 250 ml of mb dye solution (with a different values of concentrations) using overhead stirrer (with various rotational speed) for 3 minutes. third stage: in this stage mb dye was extracted by settling after 15 minutes and the samples were measured by uv spectrophotometer, fig. 3 shows a schematic diagram for emulsion liquid membrane for extracted mb dye from aqueous solution. m. a. mohammed et al. / iraqi journal of chemical and petroleum engineering 21,3 (2020) 39 44 41 fig. 3. schematic diagram of emulsion liquid membrane process for mb dye extraction at different values of operating conditions, several parameters were examined as shown in table 1. table 1. operation conditions and extraction parameters no. operating conditions values 1 h2so4 conc. 0.25-1.5 m 2 agitation speed 50-250 rpm 3 dye conc. 6 -16 ppm 4 diluent type hexane heptane kerosene by using uv the concentration of dye ion was determined by absorbent of light through the dye solutions. the percentage of extraction efficiency was calculated by using the following equation: extraction efficiency (%) = c0− c c0 ∗ 100 (1) where: c0: initial dye concentration in the feed phase at t = 0 (ppm). c: final dye concentration in the feed phase at the end of the extraction process (ppm). 4results and discussion 4.1. effect of h2so4 concentration in the stripping phase effect of sulfuric acid concentration (h2so4) of the stripping phase on extraction of the mb was studied from 0.25 m to 1.5 m. fig. 4 shows that the increase in sulfuric acid concentration increases the percent of mb extraction. at 1.25 m of h2so4 conc. maximum extraction of 98.7% was occurred. further increase (higher than 1.25m) would decreases the extraction efficiency because reduces less active h + to decompose the complex the higher strength of the acid solution which results in a lower activity coefficient of hydrogen ions. the properties of span80 may be degraded and destabilized the emulsion which resulting a high rate of rupture by the reaction products [22]. fig. 4. effect of h2so4 concentration on mb extraction (diluent = hexane, agitation speed: 200 rpm, dye conc.10 ppm) 4.2. effect of agitation speed agitation speed during extraction is an important factor. 50, 100, 150, 200 and 250 rpm are the speeds used fig. 5 the results of the influence of agitation speed on the extraction showed that the increasing of the agitation speed from 50 to 200 rpm increased the shear force which acts on the globules of emulsion (the emulsion globules would be smaller) because the area of mass transfer increased. beyond 200 rpm not only the extraction percent decreases slightly, also makes the emulsion unstable which affected and caused implying the rupture of the emulsion, the solute expulsion already extracted from the stripping phase to feed phase [23]. the optimum agitation speed was 200 rpm for a higher extraction percent 96.8%. fig. 5. effect agitation speed on extraction of mb (diluent = hexane, h2so4 concentration 1.25 m, dye conc. 10 ppm) m. a. mohammed et al. / iraqi journal of chemical and petroleum engineering 21,3 (2020) 39 44 42 4.3. dye concentration the effect of initial dye concentration in the feed phase on the extraction process was investigated at different concentrations ranging from 6 to 16 (ppm) (these concentrations were chosen because that the products of textile factories do not exceed this range) fig. 6. the extraction percentage showed that a high concentration of methylene blue dye in the feed phase decreases the extraction efficiency, in agreement with the extraction technique by elm that is effective at low concentration of solute. the extraction percent decreased for concentrations above 10 ppm, this is due to the membrane saturation of the feed phase droplets by mb, and this behavior has also been shown in some studies [22, 24]. the optimum extraction percent (98.7%) was achieved for 10 ppm of a dye concentration. fig. 6. effect dye concentration on extraction of mb (diluent = hexane, h2so4 concentration 1.25 m, agitation speed 200 rpm) 4.4. effect of diluent type experiments were done under optimum conditions as mentioned previously by also using heptane and kerosene as diluents. it was noticed that the diluents influence the efficiency of elm process. fig. 7 presents the behavior of methylene blue dye extraction using hexane, kerosene and heptane as diluents; it shows that hexane provided a better extraction percent. also, the hexane shows higher efficiency of extraction than that result using kerosene and heptane. dielectric constant (the permittivity of a substance to the permittivity of the free space) of solvent was the reason caused this behavior; hexane has a dielectric constant (1.89) that is lower than the dielectric constant of kerosene (2.1) and heptane (1.92) that made the rate of transfer higher. and the water oil emulsion produced using hexane is much more stable than that prepared using heptane and kerosene [23]. fig. 7. effect of diluents type on extraction efficiency: h2so4 concentration 1.25 m, agitation speed 200 rpm, dye conc.10 ppm) 5conclusion the extraction of the methylene blue (mb) was the main objective of this study. the study of an emulsion liquid membrane process using several important factors indicated that: 1for high h2so4 concentrations, span 80 loses its surfactant properties, and then the optimum concentration of acid was 1.25 m. 2increasing the agitation speed causes rupture of emulsion. 3increasing the initial concentration of mb dye above 200 rpm decreases the extraction efficiency because the saturation of the stripping phase droplets by the dye. 4the optimal diluent was hexane because of that the lower dielectric constant. references [1] rosmawani mohammad, aswinee tangga rajoo and mardawani mohamad (2017 "coconut fronds as adsorbent in the removal of malachite green dye." j. eng. appl. sci. 12 (2017): 996-1001. [2] s. elumalai1, s. sathya1,g. muthuraman "recovery of dye from wastewater using liquid-liquid extraction and bulk liquid membrane techniques." international journal of chemtech research 7, no. 7 (2015): 30893094. [3] zeinab m. abou-gamra, mohamed a. ahmed, "tio 2 nanoparticles for removal of malachite green dye from waste water." advances in chemical engineering and science 5, no. 03 (2015): 373. [4] hunger, k. (ed.). industrial dyes: chemistry, properties, applications. john wiley & sons, 2007. [5] muthuraman g, teng tt. "extraction and recovery of rhodamine b, methyl violet an methylene blue from industrial wastewater using d2ehpa as an extractant". j indeng chem., 2009, 15; 841-846. http://www.arpnjournals.org/jeas/research_papers/rp_2017/jeas_0217_5716.pdf http://www.arpnjournals.org/jeas/research_papers/rp_2017/jeas_0217_5716.pdf http://www.arpnjournals.org/jeas/research_papers/rp_2017/jeas_0217_5716.pdf http://www.arpnjournals.org/jeas/research_papers/rp_2017/jeas_0217_5716.pdf https://www.researchgate.net/profile/g_muthuraman/publication/279916326_recovery_of_dye_from_wastewater_using_liquid-liquid_extraction_and_bulk_liquid_membrane_techniques/links/559e018008ae76bed0bb568a/recovery-of-dye-from-wastewater-using-liquid-liquid-extraction-and-bulk-liquid-membrane-techniques.pdf https://www.researchgate.net/profile/g_muthuraman/publication/279916326_recovery_of_dye_from_wastewater_using_liquid-liquid_extraction_and_bulk_liquid_membrane_techniques/links/559e018008ae76bed0bb568a/recovery-of-dye-from-wastewater-using-liquid-liquid-extraction-and-bulk-liquid-membrane-techniques.pdf https://www.researchgate.net/profile/g_muthuraman/publication/279916326_recovery_of_dye_from_wastewater_using_liquid-liquid_extraction_and_bulk_liquid_membrane_techniques/links/559e018008ae76bed0bb568a/recovery-of-dye-from-wastewater-using-liquid-liquid-extraction-and-bulk-liquid-membrane-techniques.pdf https://www.researchgate.net/profile/g_muthuraman/publication/279916326_recovery_of_dye_from_wastewater_using_liquid-liquid_extraction_and_bulk_liquid_membrane_techniques/links/559e018008ae76bed0bb568a/recovery-of-dye-from-wastewater-using-liquid-liquid-extraction-and-bulk-liquid-membrane-techniques.pdf https://www.researchgate.net/profile/g_muthuraman/publication/279916326_recovery_of_dye_from_wastewater_using_liquid-liquid_extraction_and_bulk_liquid_membrane_techniques/links/559e018008ae76bed0bb568a/recovery-of-dye-from-wastewater-using-liquid-liquid-extraction-and-bulk-liquid-membrane-techniques.pdf https://www.scirp.org/html/16-3700600_58365.htm https://www.scirp.org/html/16-3700600_58365.htm https://www.scirp.org/html/16-3700600_58365.htm https://www.scirp.org/html/16-3700600_58365.htm https://books.google.iq/books?hl=en&lr=&id=uazs4hk2tgwc&oi=fnd&pg=pr5&dq=%5b4%5d%09hunger,+k.+(ed.).+industrial+dyes:+chemistry,+properties,+applications.+john+wiley+%26+sons,+2007.&ots=e6unforadv&sig=i5okpnqn_nkrfjcqcs9lpnahvwk&redir_esc=y#v=onepage&q=%5b4%5d%09hunger%2c%20k.%20(ed.).%20industrial%20dyes%3a%20chemistry%2c%20properties%2c%20applications.%20john%20wiley%20%26%20sons%2c%202007.&f=false https://books.google.iq/books?hl=en&lr=&id=uazs4hk2tgwc&oi=fnd&pg=pr5&dq=%5b4%5d%09hunger,+k.+(ed.).+industrial+dyes:+chemistry,+properties,+applications.+john+wiley+%26+sons,+2007.&ots=e6unforadv&sig=i5okpnqn_nkrfjcqcs9lpnahvwk&redir_esc=y#v=onepage&q=%5b4%5d%09hunger%2c%20k.%20(ed.).%20industrial%20dyes%3a%20chemistry%2c%20properties%2c%20applications.%20john%20wiley%20%26%20sons%2c%202007.&f=false https://www.sciencedirect.com/science/article/abs/pii/s1226086x09001890 https://www.sciencedirect.com/science/article/abs/pii/s1226086x09001890 https://www.sciencedirect.com/science/article/abs/pii/s1226086x09001890 https://www.sciencedirect.com/science/article/abs/pii/s1226086x09001890 m. a. mohammed et al. / iraqi journal of chemical and petroleum engineering 21,3 (2020) 39 44 43 [6] elumalai s, muthuraman g, sathya m, soniyam,teng tt. "recovery of dye from textile effluents using phenol as an extractant". j indeng chem., 2014, 20; 1958-1964. [7] muthuraman g, teng tt, leh cp, norli i. "use of bulk liquid membrane for the removal of chromium (vi) from aqueous acidic solutions with tri-n-butyl phosphate as a carrier". desalination.,2009, 249; 884890. [8] elumalai s, muthuraman g. "comparative study of liquid-liquid extraction and bulk liquid membrane for rhodamine b". inter. j enginnov technol., 2013, 3; 387-392. [9] m joshi, r bansal, and r purwar, "colour removal from textile effluents." (2004). 239-259. [10] r.d.noble and j.douglas way, "liquid membrane technology: an overview." 1987. 8, 110-122. [11] adel al-hemiri and wasano.noori. "extraction of atropine from datura innoxia using liquid membrane technique" iraqi journal of chemical and petroleum engineeringvol.10no.1(march2009)23-27 [12] muthuraman g, teng tt, cheu peng leh, norli i (2009) "extraction and recovery of methylene blue from industrial wastewater using benzoic acid as an extractant", j hazard mater 163: 363-369. [13] marchetti. p., m.f.j.solomon, g.szekely,and a.g.livingston, 2014. "molecular separation with organic solvent nanofiltration" a critical review, chemical reviews,114 (21): 10735–10806. [14] m .sathya, g. muthuraman* and s. elumalai,(2016)," bulk liquid membrane process for the transport and kinetics study of malachite green from textile wastewater" iranica journal of energy and environment 7(3): 294-303. [15] tjoon tow teng* and amir talebi,(2012)" green liquid membrane: development and challenges",j memb sci technol,volume 2 , issue 3 . [16] chang sh, teng tt, ismail n, alkarkhi af (2011) "selection of design parameters and optimization of operating parameters of soybean oil-based bulk liquid membrane for cu(ii) removal and recovery from aqueous solutions"j hazard mater 190: 197-204. [17] hernandez.a., j.a.ibañez, a.f.tejerina, 1986. "a selective parameter for ionic membrane transport selectivity and porosity of several passive membranes." in membranes and membrane processes, pp. 93-99. springer, boston, ma, 1986. [18] majeed, najwa saber, and manal adnan mohammed. "phenol removal from aqueous solution using emulsion liquid membrane process: batch experimental studies." association of arab universities journal of engineering sciences 24.3 (2017): 135-149. . [19] patro, b. litusha. "application of liquid membrane in removal of dyes." phd diss., 2016. [20] mokhtari, bahram, and kobra pourabdollah. "emulsion liquid membrane for selective extraction of bi (iii)." chinese journal of chemical engineering 23, no. 4 (2015): 641-645. [21] sabnis, ram wasudeo. handbook of biological dyes and stains: synthesis and industrial applications. john wiley & sons, 2010. [22] bahloul, lynda, fadhel ismail, and med el-hadi samar. "extraction and desextraction of a cationic dye using an emulsified liquid membrane in an aqueous solution." energy procedia 36 (2013): 1232-1240. [23] m. djenouhat, oualid hamdaoui, mahdi chiha, and mohamed h. samar. "ultrasonication-assisted preparation of water-in-oil emulsions and application to the removal of cationic dyes from water by emulsion liquid membrane: part 2. permeation and stripping." separation and purification technology 63, no. 1 (2008): 231-238. [24] salima, aitali, et al. "cationic dye (mb) removal using polymer inclusion membrane (pims)." procedia engineering 33 (2012): 38-46. https://www.sciencedirect.com/science/article/abs/pii/s1226086x13004371 https://www.sciencedirect.com/science/article/abs/pii/s1226086x13004371 https://www.sciencedirect.com/science/article/abs/pii/s1226086x13004371 https://www.sciencedirect.com/science/article/abs/pii/s1226086x13004371 https://www.sciencedirect.com/science/article/abs/pii/s0011916409009473 https://www.sciencedirect.com/science/article/abs/pii/s0011916409009473 https://www.sciencedirect.com/science/article/abs/pii/s0011916409009473 https://www.sciencedirect.com/science/article/abs/pii/s0011916409009473 https://www.sciencedirect.com/science/article/abs/pii/s0011916409009473 https://www.semanticscholar.org/paper/comparative-study-of-liquid-liquid-extraction-and-b-elumalai-muthuraman/1004708a9a1d34cfc6c73df648e6e0a92124f121?p2df https://www.semanticscholar.org/paper/comparative-study-of-liquid-liquid-extraction-and-b-elumalai-muthuraman/1004708a9a1d34cfc6c73df648e6e0a92124f121?p2df https://www.semanticscholar.org/paper/comparative-study-of-liquid-liquid-extraction-and-b-elumalai-muthuraman/1004708a9a1d34cfc6c73df648e6e0a92124f121?p2df https://www.semanticscholar.org/paper/comparative-study-of-liquid-liquid-extraction-and-b-elumalai-muthuraman/1004708a9a1d34cfc6c73df648e6e0a92124f121?p2df http://nopr.niscair.res.in/handle/123456789/24631 http://nopr.niscair.res.in/handle/123456789/24631 https://pubs.acs.org/doi/abs/10.1021/bk-1987-0347.ch001 https://pubs.acs.org/doi/abs/10.1021/bk-1987-0347.ch001 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/394 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/394 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/394 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/394 https://www.sciencedirect.com/science/article/abs/pii/s0304389408010029 https://www.sciencedirect.com/science/article/abs/pii/s0304389408010029 https://www.sciencedirect.com/science/article/abs/pii/s0304389408010029 https://www.sciencedirect.com/science/article/abs/pii/s0304389408010029 https://pubs.acs.org/doi/full/10.1021/cr500006j https://pubs.acs.org/doi/full/10.1021/cr500006j https://pubs.acs.org/doi/full/10.1021/cr500006j https://pubs.acs.org/doi/full/10.1021/cr500006j http://www.ijee.net/article_64641_83c5edbdb705bd55462caef321d6bc75.pdf http://www.ijee.net/article_64641_83c5edbdb705bd55462caef321d6bc75.pdf http://www.ijee.net/article_64641_83c5edbdb705bd55462caef321d6bc75.pdf http://www.ijee.net/article_64641_83c5edbdb705bd55462caef321d6bc75.pdf http://www.ijee.net/article_64641_83c5edbdb705bd55462caef321d6bc75.pdf https://www.longdom.org/open-access/green-liquid-membrane-development-and-challenges-2155-9589.1000e106.pdf https://www.longdom.org/open-access/green-liquid-membrane-development-and-challenges-2155-9589.1000e106.pdf https://www.longdom.org/open-access/green-liquid-membrane-development-and-challenges-2155-9589.1000e106.pdf https://www.sciencedirect.com/science/article/abs/pii/s0304389411003281 https://www.sciencedirect.com/science/article/abs/pii/s0304389411003281 https://www.sciencedirect.com/science/article/abs/pii/s0304389411003281 https://www.sciencedirect.com/science/article/abs/pii/s0304389411003281 https://www.sciencedirect.com/science/article/abs/pii/s0304389411003281 https://link.springer.com/chapter/10.1007/978-1-4899-2019-5_11 https://link.springer.com/chapter/10.1007/978-1-4899-2019-5_11 https://link.springer.com/chapter/10.1007/978-1-4899-2019-5_11 https://link.springer.com/chapter/10.1007/978-1-4899-2019-5_11 https://link.springer.com/chapter/10.1007/978-1-4899-2019-5_11 https://jaaru.org/index.php/auisseng/article/view/59 https://jaaru.org/index.php/auisseng/article/view/59 https://jaaru.org/index.php/auisseng/article/view/59 https://jaaru.org/index.php/auisseng/article/view/59 https://jaaru.org/index.php/auisseng/article/view/59 https://jaaru.org/index.php/auisseng/article/view/59 http://ethesis.nitrkl.ac.in/8282/ http://ethesis.nitrkl.ac.in/8282/ https://www.sciencedirect.com/science/article/abs/pii/s1004954114002079 https://www.sciencedirect.com/science/article/abs/pii/s1004954114002079 https://www.sciencedirect.com/science/article/abs/pii/s1004954114002079 https://www.sciencedirect.com/science/article/abs/pii/s1004954114002079 https://books.google.iq/books?hl=en&lr=&id=_la8dwaaqbaj&oi=fnd&pg=pr17&dq=%5b21%5d+sabnis,+ram+wasudeo.+handbook+of+biological+dyes+and+stains:+synthesis+and+industrial+applications.+john+wiley+%26+sons,+2010.&ots=kull5pnxzg&sig=pzih1zt3inlmr0xb94pagkaqn4s&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=_la8dwaaqbaj&oi=fnd&pg=pr17&dq=%5b21%5d+sabnis,+ram+wasudeo.+handbook+of+biological+dyes+and+stains:+synthesis+and+industrial+applications.+john+wiley+%26+sons,+2010.&ots=kull5pnxzg&sig=pzih1zt3inlmr0xb94pagkaqn4s&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=_la8dwaaqbaj&oi=fnd&pg=pr17&dq=%5b21%5d+sabnis,+ram+wasudeo.+handbook+of+biological+dyes+and+stains:+synthesis+and+industrial+applications.+john+wiley+%26+sons,+2010.&ots=kull5pnxzg&sig=pzih1zt3inlmr0xb94pagkaqn4s&redir_esc=y#v=onepage&q&f=false https://www.sciencedirect.com/science/article/pii/s1876610213012253 https://www.sciencedirect.com/science/article/pii/s1876610213012253 https://www.sciencedirect.com/science/article/pii/s1876610213012253 https://www.sciencedirect.com/science/article/pii/s1876610213012253 https://www.sciencedirect.com/science/article/pii/s1383586608001986 https://www.sciencedirect.com/science/article/pii/s1383586608001986 https://www.sciencedirect.com/science/article/pii/s1383586608001986 https://www.sciencedirect.com/science/article/pii/s1383586608001986 https://www.sciencedirect.com/science/article/pii/s1383586608001986 https://www.sciencedirect.com/science/article/pii/s1383586608001986 https://www.sciencedirect.com/science/article/pii/s1383586608001986 https://www.researchgate.net/profile/senhadji-kebiche_ounissa2/publication/257724305_cationic_dye_mb_removal_using_polymer_inclusion_membrane_pims/links/53eacac80cf2dc24b3ce74db/cationic-dye-mb-removal-using-polymer-inclusion-membrane-pims.pdf https://www.researchgate.net/profile/senhadji-kebiche_ounissa2/publication/257724305_cationic_dye_mb_removal_using_polymer_inclusion_membrane_pims/links/53eacac80cf2dc24b3ce74db/cationic-dye-mb-removal-using-polymer-inclusion-membrane-pims.pdf https://www.researchgate.net/profile/senhadji-kebiche_ounissa2/publication/257724305_cationic_dye_mb_removal_using_polymer_inclusion_membrane_pims/links/53eacac80cf2dc24b3ce74db/cationic-dye-mb-removal-using-polymer-inclusion-membrane-pims.pdf m. a. mohammed et al. / iraqi journal of chemical and petroleum engineering 21,3 (2020) 39 44 44 ميثيلين الزرقاء الكاتيونيةتطبيق عملية الغشاء السائل المستحلب الستخراج الصبغة methylene blue 2و هدى عادل صبار 1, وسن عمر نوري1منال عدنان محمد كلية الهندسة/جامعة بغداد1 كلية الهندسة الخوارزمي/جامعة بغداد2 الخالصة ميثيلين اليصف العمل الحالي تطبيق عملية الغشاء السائل المستحلب على استخراج صبغة كاتيونية ) كمستلحب ، محلول حامض الكبريتيك كعامل span 80طور الغشاء يتكون من ( من محلول مائي.الزرقاء النتزاع الصبغة و الهكسان كمخفف. في العمل الحالي ، تمت دراسة العوامل ذات التاثير الواضح على استخراج صبغة الميثيلين الزرقاء. وتشمل مرحلة تخلل الصبغة، وتركيز الصبغة في طور االنتزاع، وسرعة التحريك عند h2so4هذه العوامل تركيز االبتدائية ونوع المادة المخففة. h2so4عند الظروف االتيه :تركيز الحامض تم استخالصها % من صبغة المثيلين الزرقاء98اكثر من جزء في المليون وافضل نوع (10) ( دورة في الدقيقة ، تركيز الصبغة 200، سرعة التحريك )موالري (1.25) مخفف كان الهكسان . ، الغشاء السائل المستحلب. الكاتيونية( ، الصبغة mbالكلمات الدالة: ازالة صبغة، الميثيلين األزرق ) available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol. 24 no.1 (march 2023) 125 – 136 eissn: 2618-0707, pissn: 1997-4884 *corresponding author: name: zahraa a. mahdi, email: arashikeyoto21@gmail.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. a review on models for evaluating rock petrophysical properties zahraa a. mahdi * and ghanim m. farman petroleum engineering department, college of engineering, university of baghdad, iraq abstract the evaluation of subsurface formations as applied to oil well drilling started around 50 years ago. generally, the curent review articule includes all methods for coring, logging, testing, and sampling. also the methods for deciphering logs and laboratory tests that are relevant to assessing formations beneath the surface, including a look at the fluids they contain are discussed. casing is occasionally set in order to more precisely evaluate the formations; as a result, this procedure is also taken into account while evaluating the formations. the petrophysics of reservoir rocks is the branch of science interested in studying chemical and physical properties of permeable media and the components of reservoir rocks which are associated with the pore and fluid distribution. throughout recent years, several studies have been conducted on rock properties, such as porosity, permeability, capillary pressure, hydrocarbon saturation, fluid properties, electrical resistivity, self-or natural-potential, and radioactivity of different types of rocks. these properties and their relationships are used to evaluate the presence or absence of commercial quantities of hydrocarbons in formations penetrated by, or lying near, the wellbore. a principal purpose of this paper is to review the history of development the most common techniques used to calculate petrophysics properties in the laboratory and field based primarily on the researchers and scientists own experience in this field. keywords: petrophysical properties, hydrocarbon, reservoir, shale volume, porosity, water saturation, permeability, petroleum technology, interpretation. received on 12/06/2022, received in revised form on 07/08/2022, accepted on 08/08/2022, published on 30/03/2023 https://doi.org/10.31699/ijcpe.2023.1.14 1introduction interpretation of well log results is one of the important processes for engineers and geologists to classify the petrophysical properties. the log data is important in reservoir engineering calculations, especially in the estimation of the reserve. the best interpretation for any structure of interest is influenced by the quality and quantity of log data available to analysts and the type of problem [1]. generally, there are two types of data when analyzing these properties; instrumental methods that measure the properties vs. depth, which are called logs; and real samples that exactly represent the formation that we are dealing with, such as cores and cuttings [2] . the cross plot methods are common means to display the effect of combinations of logs on lithology and porosity, and they give a visual idea of the type of lithology mixtures [3]. the quantitative estimation of a hydrocarbon unit in any formation requires a correct estimate of shale volume, which causes a blockage to the pore space and decreases the amount of permeability, which, as a result, decreases the reservoir quality [4]. there are several methods for calculating porosity, including laboratory testing and/or log data. the precision of porosity found from drill cuttings can be incredibly affected by the size of the cuttings and desaturation time [5]. likewise, log analysis has been utilized for porosity determination. one of the significant parts in formation evaluation is the water saturation (sw) that is still difficult regarding well logging analysis. a water saturation estimation considering resistivity and porosity was first proposed for clean sand development and was named the archie formula. after that, a quantity of significant water saturation models emerged on traditional logging data for shale-bearing sands, such as the simandoux model , modified simandoux model [6], indonesian model, total shale model, modified total shale model , and dispersed clay model , and dual water model. that leads to good results for clean sandstone reservoirs. for petroleum engineers, permeability is a main input and an important key in reservoir management as well as in development. for example, when selecting the optimum production rate for the field and water injection patterns [7]. almost all analyses of petroleum reservoirs include a calculation of net pay. the total reservoir material that will flow an economically feasible amount of hydrocarbon under a specific production process is known as net pay [8]. if unquestioned, the significance of net pay thickness is with regard to hydrocarbon in situ and reserve estimation [8]. to differentiate between net pay intervals and non-net pay intervals, there isn't a standard procedure or approach, though. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:arashikeyoto21@gmail.com http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2023.1.14 z. a. mahdi and g. m. farman / iraqi journal of chemical and petroleum engineering 24,1 (2023) 125 136 126 2petrophysical properties determination techniques a variety of parameter techniques were applied to the petrophysical parameters. a brief review of these methods is discussed in the following subdivisions (see fig. 1). fig. 1. petophysical analysis and flow units characterization 2.1. shale volume determination one of the most public problems in formation evaluation is the impact of shale in reservoir rocks. a precise determination of formation porosity and fluid saturation in shaly sand is exposed to several uncertain parameters, all of which are prompted by the presence of shale in the pay formation. to handle this issue in the shale sand reservoir. an integrated calculation is given to determine the exact value of shale volume from various shale indicator tools, and after that, the effective porosity is determined. can summarize the methods that are used to determine the shale volume: de witte, presented his model for dispersed shale considering very shaly formations. this model can be simplified to characterize low shale formations having low values of water resistivity, in light of laboratory research and field knowledge [9]. winsaur et al., studied the ionic conductivity in double layers in reservoir rocks and presented a model for charge scattering in shaly sands. he defined the increment in the obvious conductivity of shale because of the way that clays add to the total conductivity of the rock while the rock structure is nonconductive [10]. waxman and smits, established the conductivity model of clay-bearing sandstone to explain the effects of clay additional conductivity. it assumes the same formation factor clay has a parallel conductive path to the pore water. the relationship can be described by the following equations [11]: 𝐶𝑜 = 1 𝐹 (𝐶𝑊 + 𝐶𝑒𝑥 ) (1) 𝐶𝑒𝑥 = 𝐵𝑄𝑣 (2) 𝐵 = 3.83(1 − 0.83𝑒 − 𝐶𝑤 2 ) (3) 𝑄𝑣 = 𝐶𝐸𝐶(1−∅𝑡)𝜌𝐺 ∅𝑡 (4) where eq. 1 is an empirical equation derived from na+ at 25°c, the waxman-smits model has the ability to capture the nonlinear behaviors of the saturated rock conductivity vs. the pore-water conductivity at low salinity. poupon and leveaux, developed a indonesia model to calculate high amount of shale and fresh water saturation the equation used the computer made cross plot to between the water saturation (sw) and true resistivity of formation ,the range of shale recorded (30-70%) [12]. 1 √𝑅𝑡 = [ 𝑉𝑐𝑙𝑑 √𝑅𝑐𝑙𝑎𝑦 + ∅𝑚/2 √𝑎𝑅𝑤 ]𝑆𝑤 𝑛/2 (5) where; vclay is volume of shale; rt, formation true resistivity; rw, formation water resistivity; a, tortuosity, ϕ, porosity; sw, water saturation. clavier et al., developed equation was used to estimate shale volume from gamma ray, density and neutrondensity methods [13,14] were utilized to compute total and effective porosities for older rocks. clavier neutrondensity equation [15]: 𝑉𝑠ℎ𝑎𝑙𝑒 = 𝑁𝑃𝐻𝐼𝑙𝑜𝑔−𝑁𝑃𝐻𝐼𝑚𝑎+𝑀1(𝜌𝑚𝑎−𝜌𝑙𝑜𝑔) 𝑁𝑃𝐻𝐼𝑠ℎ𝑎𝑙𝑒 −𝑁𝑃𝐻𝐼𝑚𝑎+𝑀1(𝜌𝑚𝑎−𝜌𝑠ℎ𝑎𝑙𝑒) (6) where: 𝑀 = 𝑁𝑃𝐻𝐼𝑓−𝑁𝑃𝐻𝐼𝑚𝑎 𝜌𝑓−𝜌𝑚𝑎 (7) thomas and stieber, this strategy is used to determine shale distributions, sand fractions, and sand porosity. it was chosen to account for thin-bed properties on log measurements in thin sand, fig. 2 is a geometrical solution of the thomas–stieber method for laminated sands and shales with sands containing dispersed and/or structural shale which is a base case in this interpretation. the bottom vertex of the lower triangle is the dispersed shale endpoint where the clean sand pore is filled with dispersed shale and top vertex of the upper triangle is the structural shale endpoint where the grain of the original sand is completely replaced with shale [15, 16]. fig. 2. thomas and stieber (1975) geometrical solution [7] fertl and chilingarian, presented the standard shaly clastic reservoir rocks commonly hold variable amounts z. a. mahdi and g. m. farman / iraqi journal of chemical and petroleum engineering 24,1 (2023) 125 136 127 of clay minerals. the basic properties of the most common public clay minerals vary significantly, including chemical composition, matrix density, photoelectric cross-sections, hydrogen index (hi), cation exchange capacity (cec), potassium, thorium, and uranium (in present unit) [17]. mohammadhossein mohammadlou et al., in this study, reservoir clay volume is calculated using fine-grained clastic sedimentary rocks composed of clay and pieces of other minerals, such as carbonates and siliciclastic. the nmr log is used as an easy tool to assess the veracity of the shale volume estimate from gamma-ray and spectral gamma-ray logs (most clay minerals contain variable amounts of water trapped in the mineral structure). in the lowermost reservoir region, the inconsistency between the shale quantities calculated by different approaches is substantial. sem analysis was used to detect the mineralogy and mineral volume fractions in order to solve the problem. the sem data was used as a reference point for calibrating the spectral gamma-ray log in order to determine the shale volume [18]. 2.2. porosity determination methods porosity is the ratio of the pore or void volume to the macroscopic or bulk volume, and there are many types of porosity. the average flux in pores is associated with the bulk darcy flux. it varies between 0.1 and 50%. the porosity is directly measured in the laboratory by (collecting cuttings) or from drilling data. 2.2.1. porosity measured in the laboratory by (collecting cutting) onyia, the shown relationship between ucs and porosity utilizes warren's roller cone penetration rate model. for this situation, the ucs is determined straight from log and drilling data. the onyia strategy is used on a variety of lithologies, including both shale and sandstone [19]. vojko matko, the stochastics method was utilized to assess porosity; this method employs a very sensitive sensor with less uncertainty in measuring results and less effect from disruptive noise signals. it is much simpler than the helium pycnometer approach. furthermore, no water is placed on the material. the soil or rock sample is instead immersed in water. due to stability and long-term repetition, the porosity sensor employs sensitive capacitive-dependent crystals (40 mhz with stability of 1 ppm in the temperature range of 5 to +55 °c). the direct digital method (ddm) reduces the influence of disturbances, which reduces the uncertainty of the outcome [20]. erfourth et al., this technique uses ucs data that has been collected from laboratory analysis on core, cast, and tuff samples to compute the porosity. the onyia method yields much higher porosity values for low ucs sectors than the erfourth method, but the erfourth method becomes inexact for high ucs sectors. the onyia correlation also becomes relatively constant at a ucs value of 100 mpa [21]. d el abassi, a ibhi, et al., the scientists used an ultrasonic reflectivity technique to measure the porosity, tortuosity, and longitudinal ultrasound velocity of meteorites in this study. they measured the ultrasound reflection coefficient of the surface of polished meteorite thin plates at two oblique angles of incidence and normal incidence. in comparison to other existing laboratory procedures, determining porosity with this method is simple, quick, inexpensive, and non-destructive. in the analyzed meteorite specimens, they discovered a good linear association between density and porosity, as well as a good linear correlation between the logarithm of porosity and the longitudinal velocity of ultrasound. this suggests that the porosity of these meteorites can be estimated using a simple linear mathematical relationship based on the longitudinal velocity of ultrasonic vibrations [22]. 2.2.2. porosity measured in the laboratory from drilling data westbrook and redmond, this study applied a singleunit arrangement of capillary diaphragm. this technique provided a means to measure the bulk volume of a great number of particles, such as drill cuttings. this method is quite accurate and reduces errors present in former solutions to measure the porosity of drill cuttings [23]. horsund chang et., the researchers in this study used the gamma ray method to collect data from both core and cuttings analyses. to create precise correlations for sandstone and shale porosity versus ucs and make correlations between the ucs and porosity in sandstone and shale lithologies [24]. siddiqui et al., in this study, applied (histogram-based analysis) techniques using laboratory tools to crush the plug into cuttings with various mesh sizes to show the full description of a carbonate core plug, and afterward, the cutting samples were scanned with a ct-scanner to determine (bulk densities and porosities) [25]. lenormand and fonta, in this study, the (a medicalbased ct-scan method) was re-examined and showed that the accuracy decreased for the cuttings with a diameter of less than 2.5 mm. in order to obtain consistent porosity from cutting with the sizes down to 0.5 mm, [26]. 2.3. water saturation determination methods water saturation dispersion is the main factor in formation evaluation. the right estimation of water saturation is required for a correct volumetric calculation, which is of commercial interest. recognizing the difference between hydrocarbons and water involving the reservoir is critical. this can be done by determining the water saturation in the area of interest since the whole saturation in the reservoir is 100%. the techniques that are used to determine the water saturation are: archie, the associations of the electrical resistance of fluids in porous media and porosity were discovered. he converted the analysis of well logs from qualitative z. a. mahdi and g. m. farman / iraqi journal of chemical and petroleum engineering 24,1 (2023) 125 136 128 analysis to quantitative analysis by proposing the in-situ equations to estimate the fluid saturations. table 1 values of archies’ parameters [15]. 𝑆𝑤 = ( 𝑎𝑅𝑤 ∅𝑡 𝑚𝑅𝑡 ) 1 𝑛 (8) table 1. values of archies’ parameter for different lithologies [27] description of rocks a m weakly cemented detrital rocks, such as sand ,sandstone ,and some limestones with a porosity range from 25 to 45 % usually tertiary in age. 0.88 1.37 moderately well cemented sedimentary rocks including sandstones and limestones, with a porosity range from 18 to 35% usually mesozoic in age. 0.62 1.72 well–cemented sedimentary rocks such with porosity in the range 5 to 25 %. 0.62 1.95 highly porous volcanic rocks, such as tuff , aa ,and pahoehoe , with porosity in the range 20 to 80 %. 3.5 1.44 rocks with less than 4% porosity , including dense igneous rocks and metamorphosed sedimentary rocks. 1.4 1.58 dunlap, in this method found the water saturation factor "n" can vary (from 1.18 to 2.90) based on core rock sort and different saturation methods [28]. dewitte, established a means to determine water saturation in dispersed shaly formations. the method known as the clay slurry model involves the clay dispersed in the pore space with a clean sand pore structure. in other words, the clay minerals in the formations are expected to exist in a slurry with the formation fluid. this model is given by the following equation [29]: 𝑆𝑤 = 1 1−𝑞 (√ 𝑎𝑅𝑤 ∅𝑡𝑚 2 + 𝑞2 4 − 𝑞 2 ) (9) wyllie and rose (1950), in the numerical sense, assumed factor (m) can range between one and infinity; however, it lies between (1.3 and 3.0) depending on the first experimental by archie 1942 [28]. hingle, suggested the graphical solution. it is the first commonly used solution to solve archie’s equation. to interpret this method, use a specially designed graph paper and look for the cementation exponent value, m, where the y-axis varies with that value. the hingle plot (fig. 3) assume the saturation exponent and cementation exponent both equal to 2.0 and rewrite the archi formula in form [30]: 1 √𝑅𝑡 = 𝑆𝑤 1 √𝑅𝑤 ∅ (10) keller, showed that electrical resistivity experiments treated sandstones. the research introduced the exponent "n" range in (1.5 to 11.7) depending on how the cores were dealt with [31]. dobrynin, presented with a factor (m) value, it can be determined as a function of lithology and pressure. furthermore, the greatest variety in (m) relies upon the quantity of small conductivity channels in the rock [32]. fig. 3. hingle plot [30] simandoux, developed a model to predict water saturation during the production of shaly sand. the model was created as a consequence of laboratory tests done on a physical a reservoir model made of synthetic sand and clay was created in the institute of english petroleum (ifp). the simandoux still one of the most common models used for water saturation models and a very important basis for subsequent research in this field. the simandoux equation [29]: 𝑆𝑤 = 𝑎𝑅𝑤 2 ∅𝑚 [( −𝑉𝑠ℎ 𝑅𝑠ℎ ) + √( 𝑉𝑠ℎ 𝑅𝑠ℎ ) 2 − ( 4∅𝑚 𝑎𝑅𝑤𝑅𝑡 )] (11) buckles, after buckles produced this technique to calculate average water saturation, he concluded that the invention of water saturation and porosity in intervals at irreducible water saturation would be a constant related to pore surface area [6]. pickett's, this strategy is based on the archie equation, which effectively used to predict main parameters (a and m) in clean formation and relies on a graphical plot to include resistivity at the water zone vs. porosity to approximation factor (m) from data of well logs (fig. 4) [33, 30]. log 𝑅𝑡 = −𝑚𝑙𝑜𝑔∅ + log( 𝑅𝑤 𝑆𝑤𝑛 ) (12) fig. 4. pickett plot [30] waxman and smith, established a dual water model depending on the cec of shale. the (cec) is measured as the main shale properties. which is expressed in milli equivalent unit pore volume of pore fluids, qv (meq/cc). z. a. mahdi and g. m. farman / iraqi journal of chemical and petroleum engineering 24,1 (2023) 125 136 129 in a general laboratory study, a saturation resistivity relationship for shaly formation was found that linked the resistivity impact of the shale to the (cec) of the shale. (waxman–smits relationship) [34, 35]. morris and biggs, the researchers in this research reached the conclusion that the porosity-water saturation produced was a fraction of bulk volume water, bvw. used as a constant (often denoted as "buckles number"). this constant is used not only to classify transition zones from zones at irreducible saturation, but also to approximation permeability. a buckles plot is a plot of water saturation (sw) vs. porosity (fig. 5). contours of equal bulk volume water (bvw) are drawn on the plot.  points plot on a hyperbolic bvw line where the formation is near immobile water if the points come from a reservoir with consistent pore type and pore geometry.  points scatter on a buckles plot where the formation falls below the top of the transition zone [36]. fig. 5. buckles constant relates to capillary pressure, fluid distribution, fluid recovery and porosity in a reservoir [36] poupon and leveaux, the formulated indonesia model [37];was established to remove the limitations of other techniques in reservoir studies when determine water saturation in laminated and shaly formations the indonesia model was developed by field observation in indonesia, rather than by laboratory experimental measurement support, also does not particularly assume any specific shale distribution. the indonesian model also has an extra feature as the only model considered the saturation exponent (n). this model is given by the following equation [29]: 1 rt = sw n 2 ( vsh 1− vsh 2 √rsh + ( ∅ m 2 √arw )) (13) miyairi and itoh, depended on the poupon et al. model (1971) for shaly sands to produce a method to obtain three shaly sand factors: a, n, and m. this strategy can be defined by using several crossplots, like true resistivity formation versus porosity (r, vs p) and true resistivity formation versus porosity of the shaly formation (r, vs cpst) [38]. ellis & singer, found the value of (n) is measured from core sample data laboratory and (n) is estimated from slope line for resistivity index (rt/ro, where ro is the water filled resistivity and rt is the true resistivity) on a log-log scale with water saturation measurements [39]. yang kebing, xie li, et al., based on archie's formula and the formation invasion model, the scientists in this study developed a formula for calculating reservoir water saturation by radial resistivity ratio under the most extensive conditions. the use of radial resistivity ratios can reduce the effect of reservoir lithology and physical property variations on water saturation calculation. a power function describes the relationship between the radial resistivity ratio and reservoir water saturation. the bigger the radial resistivity ratio, the better the reservoir's oil bearing; the lower the radial resistivity ratio, the worse the reservoir's oil bearing; there is a one-to-one relationship between them. this approach is useful for evaluating low resistivity oil and high water layers [40]. dahai wang, jinbu li, et al., the triple-porosity model was established for determining the cementation exponent of triple-porosity media reservoirs by merging the maxwell-garnett theory and the series-parallel theory, which corresponded with genuine physical-experiment data of rocks.they developed a new model based on the link between total porosity and cementation exponent m of a triple-porosity medium composite system with various combinations of fractures and nonconnected vug porosity. the results showed that the fractures decreased the reservoir's cementation exponent while the vugs rose. because of the mixture of matrix pores, fractures, and vugs, the cementation exponent of the triple-porosity media reservoir varied around 2.0. the cementation exponent proposed in the work could reasonably predict z. a. mahdi and g. m. farman / iraqi journal of chemical and petroleum engineering 24,1 (2023) 125 136 130 the cementation exponent of the strongly inhomogeneous triple-porosity media reservoir [41]. 2.4. permeability determination methods typically, permeability data are obtained through routine analysis in the field or laboratory core analysis is one of the most reliable techniques to determine permeability, with the disadvantages of high cost and time-consuming. an average value of permeability could be obtained by well testing, which gives information on the extension and connectivity of the reservoir. by applying the (mdt) technique, more accurate permeability data can also be achieved. the nmr log is now widely used to provide a fast estimation of the permeability profile along the wells. the most important methods developed to measure the permeability are: carman-kozeny, developed an equation to evaluate permeability (k). the result of this calculation was a mixing between darcy’s and poiseuille’s laws. where darcy’s law macroscopically quantifies fluid flow, poiseuille’s law explains the parabolic displacement of a viscous fluid in a straight-circular tube. the semianalytical carman-kozeny (ck) equation does not correctly capture the permeability’s dependence on porosity because (a) this equation has been derived for a solid medium with pipe conduits, rather than for a granular medium and (b) even if a grain size is used in this equation, it is not obvious that it does not vary with varying porosity [42, 43]. dh = 4εv sv = 4ε (1−ε)av = εd (1−ε) (14) where: 𝑎𝑣 = 𝑝𝑎𝑟𝑡𝑖𝑐𝑙𝑒 𝑠𝑢𝑟𝑓𝑎𝑐𝑒 𝑝𝑎𝑟𝑡𝑖𝑐𝑙𝑒 𝑣𝑜𝑙𝑢𝑚𝑒 (15) wyllie and rose, they proposed a modification of the carman-kozeny equation to calculate permeability from irreducible water saturation and formation resistivity factor (fig. 6). many assumptions about their equation are made. firstly, there is no variance between minimum water saturation and irreducible water saturation. secondly, this value of water saturation is a linear function of the grain surface. finally, the same tortuosity of the porous media exerts an influence on the electrical conductivity as well as on the flow of the wetting phase fluid [44]. k = p∅q swir (16) where, wyllie-rose relationship is a generalized equation that requires the determination of values for the constants p, q, and r to be calibrated from core measurements. tixier, the tixier equation generated the experimental permeability equation by utilizing the wyllie rose equation. the outcomes of the tixier equation were approximately similar to the permeability calculations from the morris-biggs gas equation [46]. gary and fatt, investigated the influence of stress on sandstone permeability, finding that not only rock permeability, but also permeability anisotropy in many sandstones, is a function of overburden pressure, and permeability reduction owing to stress effect is also a function of the radial to axial stress ratio [47]. fig. 6. permeability contours drawn on pickett plot of sandstone data, using a wyllie-rose relationship with both porosity and irreducible water saturation [45] morris biggs, using the wyllie rose equation, we provided permeability equations for both oil and gas reservoirs. the permeability obtained by morris-biggs in a completely gas saturated area (at irreducible water saturation) differs slightly from the permeability calculated by timur. unlike the timur model, presents the permeability equation for gas fields and does not require correlation utilizing irreducible water saturation and effective porosity of gas reservoirs [48]. 𝐾1/2 = 𝐶 ∅3 𝑆𝑤𝑖 (17) where, c = constant, oil =250, gas =80. timur, suggested equation to estimate permeability by using in-situ measurements of residual water saturation and formation porosity. he tested several options in the laboratory by taking different measurements of permeability, porosity, as well as residual water saturation depending on 155 samples of sandstone that belonged to three oil fields. the main constraint of this equation is the fixed value of the cementation exponent (m), which is equal to 1.5 while this parameter may have other values in specific conditions [49]. winland, the winland hydraulic flow unit method was applied on core data and produced five groups to predicate permeability depending on pore throat size at mercury saturation of 35%. used the r35 parameter, along with other petrophysical, geological, and engineering data, to identify flow units in five carbonate reservoirs, r35 can be computed from permeability and porosity measurements on core samples [50]. log 𝑟35 = 0.732 + 0.588 log 𝑘 − 0.8641𝑙𝑜𝑔∅ (18) in fig. 7, note that at a given porosity, permeability increases roughly as the square of the pore throat radius. and for a given throat size, the dependence of z. a. mahdi and g. m. farman / iraqi journal of chemical and petroleum engineering 24,1 (2023) 125 136 131 permeability on porosity is slightly less than φ2. hartmann and coalson also they state that r35 is a function of both entry size and pore throat sorting and is a good measure of the largest connected pore throats in a rock with intergranular porosity [24]. fig. 7. empirical model based on regression attributed to winland [51] coates and dumanoir, from irreducible water saturation and various types of effective porosity, an experimental relationship for the permeability estimates of average gravity oil reservoirs was presented[48, 52]. 𝐾1/2 = 𝐶 𝑊4 ∅2𝑊 𝑅𝑤 𝑅𝑡𝑖 (19) where: c=23+465𝜌h-188𝜌ℎ2 and 𝑊 2 = (3.75 − ∅) + 1 2 (log10 ( 𝑅𝑤 𝑅𝑡𝑖 ) + 2.2)2 bo shen, et al., they devised a method for assessing permeability in glutenite reservoirs using well logs. this technique is based on the k-c model, the geometry equivalent parameter, and the flow porosity. furthermore, the authors present a method for determining flowing porosity that can be employed by researchers interested in electrical current flow in pores. although this method is more difficult than the usual permeability estimation method, it produces a consistent and accurate result for glutenite reservoirs with high variability [53]. 2.5. net pay evaluation method well net pay is an effective thickness that is important for determining flow units and objective intervals for well completions and stimulation programs. thus, a section of the reservoir with high storability (driven by porosity), high transmissivity (driven by fluid mobility, which is defined as a ratio of permeability to fluid viscosity), and large hydrocarbon saturation is defined (driven by water saturation, sw), the most important methods developed to measure net pay are: mckenzie, the effective pore throat size was connected to show "producible and non-producible rock types." by the 𝐾 ∅ ratio (fig. 8) [54]. kolodzie, to associate the permeability and porosity with a pore throat radius (r) equal to varied mercury saturations, the winland method was developed. he discovered that the 35th percent, or 35 percent of the pore volume ("r35," where he saw the inflexion on the mercury injection capillary curve vs. mercury saturation), had the best correlation with the spindle field data (it corresponds to a 0.5 m pore throat threshold value) [55]. fig. 8. porosity cut off [26] worthington and cosentino, summarized that the cutoff values should be "dynamically conditioned" with a hydraulic parameter like pore throat radius, absolute permeability, or fluid mobility [56]. jensen and menke, the accuracy and mistakes in approximating multiple porosity cut-off values were investigated using a probabilistic approach. to calculate porosity cut-off values, they used a semilog porosity vs. permeability plot and the y-on-x regression line. the regression line delivers the best results for estimating the net pay, while the rma line gives the best results for ngr. [57]. proposed method, this method (based on diffusivity equation) diffusivity equation is designed to determine the pressure as a function of time and distance from the well for a radial flow regime of slightly compressible fluids. ∂2p ∂r2 + 1 r ∂p ∂r = ∅μc 0.000264k ∂p ∂t (20) if a net pay zone has a greater flow rate in comparison to the other net pay zone, we can rank the first zone in a higher grade in comparison to the second one. pressure is an important parameter causing fluid flow in hydrocarbon reservoirs as it can be inferred from darcy’s law. in the proposed method, division of flow rate by pressure difference is introduced as an index for net pay determination, after that, this index is calculated from diffusivity equation [8]. lucia, demonstrated that by plotting interparticle porosity against permeability in carbonate reservoirs (fig. 9), one could derive the type of rock fabric and detect pore-size classes. additional pore types (vuggy, dissolution-enhanced) might modify these relationships. the permeability and porosity cut-off values should be defined based on these considerations. a unique permeability cut-off value based on engineering considerations (i.e. mainly depending on the fluid mobility) will lead to several porosity cut-off values depending on the rock fabric, i.e. the particle size [8, 58]. z. a. mahdi and g. m. farman / iraqi journal of chemical and petroleum engineering 24,1 (2023) 125 136 132 fig. 9. lucia model for porosity-permeability relationships based on rock fabric [59] jensen and menke, used a probabilistic approach to analyze the accuracy and errors in prediction of various porosity cut-off values. in the case where either determination of reservoir ngr and/or np is obtained by cross-plotting surrogate quantities as sw, vsh, and/or φ, investigating the errors inherent to the regression methods giving log (k) vs. φ best fit lines is crucial since the misuse of regression methods may lead to additional errors. such statistical issues related to the selection of porosity cut-offs based on regression lines [60]. 3conclusion the main scope of this paper is to provide a general review of the development of the field of formation evaluation and the available studies and applications to solve the problem. after reviewing a fair number of studies and papers on the formation evaluation studies the following were made: 1. the most popular and accurate method for determining shale volume is the gamma ray (single clay indicator method) to calculate shale volume. this method can be used for any formation that has shaly layers. the factor that effects clay volume calculating is the hole size, which refers to a large volume of drilling mud, has an impact on the gammaray record, and the reading can be influenced by environmental adjustment. 2. using drilling data to achieve modified porosity and ucs values is beneficial in various formations. the modifications are not only applied in sandstone and shale formations, but the addition of gamma ray data permits such modifications to be possible for calculating porosity in formations of varied lithologies. they used drilling data in combination with the gamma ray (a better indicator) to determine porosity. 3. water saturation factor can be computed using an intermediate parameter such as shale volume in sandstone reservoirs or directly anticipated from core data, well logs, or seismic characteristics. well log data has been used to assess water saturation since 1942, when the archie formula was introduced. to address the issue of needed water saturation approximation from core analysis in previous works, interpretation has recently used seismic data to directly calculate water saturation values or estimate proper rock physical properties such as shale volume, both of which are useful in the water saturation estimation process. these strategies make use of artificial intelligence computational agents to discover previously unknown non-linear correlations between seismic properties and the reservoir property of interest, which in this case is the water level. 4. there are two types of permeability approaches (nonexperimental and experimental). some theoretic methods are used in non-experimental methods to approximate the permeability, taking into account a fully saturated domain (kozeny carman), whereas laboratory methods combine three types of classifications: capillary effects (saturated and unsaturated), flow regime (constant pressure and constant flow), and flow direction (unidirectional and radial); then, the mathematical model of the method is established, taking into account such a combination. 5. the systematic use of ordinary least-squares regression for determining porosity cut-off values from permeability cut-off values may result in erroneous results and does not ensure good np and ngr estimation. the regression line, as defined by jensen and menke, mathematically guesses the ideal porosity cut-off values by the use of another line, the major reduced axis. nomenclature (cec) cation exchange capacity (φt ) total porosity (𝜌g) average particle density of rock (𝜌f) effective fluid density in flushed (invaded) zone (𝜌mf) a density of mud filtrate (𝜌ma) a density of matrix (sem) scanning electron microscopes (hi) hydrogen index (ucs) unconfined compressive strength (rop) rate of penetration (bvw) bulk volume water (mdt) modular dynamics tester (rqi) reservoir quality index (hfu) hydraulic flow unit (np) net pay (ngr) net to gross ratio (n) water saturation exponent (m) cementation factor (r35) the pore throat radius at 35% mercury saturation (k) air permeability (φ) porosity in percent unit references [1] s. s. zughar, a. a. ramadhan, and a. k. jaber, “petrophysical properties of an iraqi carbonate reservoir using well log evaluation” iraqi j. chem. pet. eng., vol. 21, no. 1, pp. 53–59, 2020, https://doi.org/10.31699/ijcpe.2020.1.8. https://doi.org/10.31699/ijcpe.2020.1.8 z. a. mahdi and g. m. farman / iraqi journal of chemical and petroleum engineering 24,1 (2023) 125 136 133 [2] r. m. idan, a. l. m. salih, o. n. a. al-khazraji, and m. h. khudhair, “depositional environments, facies distribution, and porosity analysis of yamama formation in majnoon oilfield. sequence stratigraphic approach,” iraqi geol. j., pp. 38–52, 2020, https://doi.org/10.46717/igj.53.1d.4rw-202005-03. [3] h. liu, principles and applications of well logging. springer, 2017, https://doi.org/10.1007/978-3-66253383-3. [4] n. m. s. numan, “a plate tectonic scenario for the phanerozoic succession in iraq,” iraqi geol. j., vol. 30, no. 2, pp. 85–110, 1997. [5] y. yu and h. menouar, “an experimental method to measure the porosity from cuttings: evaluation and error analysis,” spe production and operations symposium, usa, 2015, https://doi.org/spe-173591ms. [6] m. amiri, j. ghiasi-freez, b. golkar, and a. hatampour, “improving water saturation estimation in a tight shaly sandstone reservoir using artificial neural network optimized by imperialist competitive algorithm–a case study,” j. pet. sci. eng., vol. 127, pp. 347–358, 2015, https://doi.org/10.1016/j.petrol.2015.01.013. [7] u. ahmed, s. f. crary, and g. r. coates, “permeability estimation: the various sources and their interrelationships,” j. pet. technol., vol. 43, no. 05, pp. 578–587, 1991, https://doi.org/10.2118/19604-pa. [8] c.f. haro, “the perfect permeability transform using logs and cores”, annual technical conference and exhibition, 2004, https://doi.org/10.2118/89516-ms. [9] c. b. dennis and t. d. lawrence, “log evaluation of clastic shaly formations using corrected rwa-ratio techniques,” spwla 25th annual logging symposium, 1984. [10] j. nykolaiszyn and g. ponnaganti, “metadata on my mind: automating troubleshooting to increase discovery of collections,” 2019. [11] y. fan, b. pan, y. guo, and j. lei, “effects of clay minerals and pore-water conductivity on saturation exponent of claybearing sandstones based on digital rock,” vol. 61, pp. 352–362, aug. 2020, https://doi.org/10.30632/pjv61n4-2020a2. [12] j. sam-marcus, e. enaworu, o. j. rotimi, and i. seteyeobot, “a proposed solution to the determination of water saturation: using a modelled equation,” j. pet. explor. prod. technol., vol. 8, no. 4, pp. 1009–1015, 2018, https://doi.org/10.1007/s13202-018-0453-4. [13] j. m. wheatley, n. s. rosenfield, g. heller, d. feldstein, and m. p. laquaglia, “validation of a technique of computer-aided tumor volume determination,” j. surg. res., vol. 59, no. 6, pp. 621– 626, 1995, https://doi.org/10.1006/jsre.1995.1214. [14] a. f. atanda, d. d. dominic, and a. k. mahmood, “theoretical framework for multi-agent collaborative knowledge sharing for competitiveness of institutions of higher learning (ihl) in malaysia”, 2012 international conference on computer & information science (iccis), 2012, http://doi.org/ 10.1109/iccisci.2012.6297208. [15] o. j. mkinga, e. skogen, and j. kleppe, “petrophysical interpretation in shaly sand formation of a gas field in tanzania,” j. pet. explor. prod. technol., vol. 10, no. 3, pp. 1201–1213, 2020, https://doi.org/10.1007/s13202-019-00819-x. [16] d. tiab and e. c. donaldson, “petrophysics: theory and practice of measuring reservoir rock and fluid transport properties”. gulf professional publishing, 2015. [17] r. m. jarvis, “judges and gambling,” unlv gaming lj, vol. 10, p. 1, 2020. [18] h. mohammadlou and m. mørk, “how log interpreter uses sem data for clay volume calculation,” 2012, http://doi.org/10.5772/35142. [19] e. c. onyia, “relationships between formation strength, drilling strength, and electric log properties,” spe annual technical conference and exhibition, 1988, https://doi.org/10.2118/18166-ms. [20] v. matko, “porosity determination by using stochastics method,” autom. časopis za autom. mjer. elektron. računarstvo i komun., vol. 44, no. 3–4, pp. 155–162, 2003. [21] b. erfourth, c. wright, n. hudyma, and m. maclaughlin, “numerical models of macroporous rock: quantifying the influence of void characteristics on elastic modulus,” golden rocks 2006, the 41st u.s. symposium on rock mechanics (usrms), jun. 17, 2006. [22] d. el abassi, a. ibhi, b. faiz, and i. aboudaoud, “a simple method for the determination of the porosity and tortuosity of meteorites with ultrasound,” j. geophys. eng., vol. 10, no. 5, p. 55003, 2013, https://doi.org/10.1088/1742-2132/10/5/055003. [23] m. a. westbrook and j. f. redmond, “a new technique for determining the porosity of drill cuttings,” vol. 165, no. 01, pp. 219–222, 1946, https://doi.org/10.2118/946219-g. [24] p. horsrud, “estimating mechanical properties of shale from empirical correlations,” spe drill. complet., vol. 16, no. 02, pp. 68–73, 2001, https://doi.org/10.2118/56017-pa. [25] s. siddiqui, a. s. grader, m. touati, a. m. loermans, and j. j. funk, “techniques for extracting reliable density and porosity data from cuttings,” spe annual technical conference and exhibition, 2005, https://doi.org/10.2118/96918-ms. [26] r. lenormand and o. fonta, “advances in measuring porosity and permeability from drill cuttings,” spe/eage reservoir characterization and simulation conference, 2007, https://doi.org/10.2118/111286-ms. https://doi.org/10.46717/igj.53.1d.4rw-2020-05-03 https://doi.org/10.46717/igj.53.1d.4rw-2020-05-03 https://www.researchgate.net/profile/nazar-numan-2/publication/262368041_a_plate_tectonic_scenario_for_the_phanerozoic_succession_in_iraq/links/02e7e5376238a22cc6000000/a-plate-tectonic-scenario-for-the-phanerozoic-succession-in-iraq.pdf https://www.researchgate.net/profile/nazar-numan-2/publication/262368041_a_plate_tectonic_scenario_for_the_phanerozoic_succession_in_iraq/links/02e7e5376238a22cc6000000/a-plate-tectonic-scenario-for-the-phanerozoic-succession-in-iraq.pdf https://www.researchgate.net/profile/nazar-numan-2/publication/262368041_a_plate_tectonic_scenario_for_the_phanerozoic_succession_in_iraq/links/02e7e5376238a22cc6000000/a-plate-tectonic-scenario-for-the-phanerozoic-succession-in-iraq.pdf https://doi.org/spe-173591-ms https://doi.org/spe-173591-ms https://doi.org/10.1016/j.petrol.2015.01.013 https://doi.org/10.2118/19604-pa https://doi.org/10.2118/89516-ms https://onepetro.org/spwlaals/proceedings-abstract/spwla-1984/all-spwla-1984/spwla-1984-r/18612 https://onepetro.org/spwlaals/proceedings-abstract/spwla-1984/all-spwla-1984/spwla-1984-r/18612 https://onepetro.org/spwlaals/proceedings-abstract/spwla-1984/all-spwla-1984/spwla-1984-r/18612 https://onepetro.org/spwlaals/proceedings-abstract/spwla-1984/all-spwla-1984/spwla-1984-r/18612 https://shareok.org/bitstream/handle/11244/334601/ala%20poster%202019.pdf?sequence=2 https://shareok.org/bitstream/handle/11244/334601/ala%20poster%202019.pdf?sequence=2 https://shareok.org/bitstream/handle/11244/334601/ala%20poster%202019.pdf?sequence=2 https://doi.org/10.30632/pjv61n4-2020a2 https://doi.org/10.1006/jsre.1995.1214 https://doi.org/10.1109/iccisci.2012.6297208 https://books.google.iq/books?hl=en&lr=&id=ygyzbgaaqbaj&oi=fnd&pg=pp1&dq=%5b16%5d%09d.+tiab+and+e.+c.+donaldson,+petrophysics:+theory+and+practice+of+measuring+reservoir+rock+and+fluid+transport+properties.+gulf+professional+publishing,+2015.&ots=4ur4oer3kz&sig=nomhsvwunloy4kr8guwqrdqeexm&redir_esc=y#v=onepage&q=%5b16%5d%09d.%20tiab%20and%20e.%20c.%20donaldson%2c%20petrophysics%3a%20theory%20and%20practice%20of%20measuring%20reservoir%20rock%20and%20fluid%20transport%20properties.%20gulf%20professional%20publishing%2c%202015.&f=false https://books.google.iq/books?hl=en&lr=&id=ygyzbgaaqbaj&oi=fnd&pg=pp1&dq=%5b16%5d%09d.+tiab+and+e.+c.+donaldson,+petrophysics:+theory+and+practice+of+measuring+reservoir+rock+and+fluid+transport+properties.+gulf+professional+publishing,+2015.&ots=4ur4oer3kz&sig=nomhsvwunloy4kr8guwqrdqeexm&redir_esc=y#v=onepage&q=%5b16%5d%09d.%20tiab%20and%20e.%20c.%20donaldson%2c%20petrophysics%3a%20theory%20and%20practice%20of%20measuring%20reservoir%20rock%20and%20fluid%20transport%20properties.%20gulf%20professional%20publishing%2c%202015.&f=false https://books.google.iq/books?hl=en&lr=&id=ygyzbgaaqbaj&oi=fnd&pg=pp1&dq=%5b16%5d%09d.+tiab+and+e.+c.+donaldson,+petrophysics:+theory+and+practice+of+measuring+reservoir+rock+and+fluid+transport+properties.+gulf+professional+publishing,+2015.&ots=4ur4oer3kz&sig=nomhsvwunloy4kr8guwqrdqeexm&redir_esc=y#v=onepage&q=%5b16%5d%09d.%20tiab%20and%20e.%20c.%20donaldson%2c%20petrophysics%3a%20theory%20and%20practice%20of%20measuring%20reservoir%20rock%20and%20fluid%20transport%20properties.%20gulf%20professional%20publishing%2c%202015.&f=false https://books.google.iq/books?hl=en&lr=&id=ygyzbgaaqbaj&oi=fnd&pg=pp1&dq=%5b16%5d%09d.+tiab+and+e.+c.+donaldson,+petrophysics:+theory+and+practice+of+measuring+reservoir+rock+and+fluid+transport+properties.+gulf+professional+publishing,+2015.&ots=4ur4oer3kz&sig=nomhsvwunloy4kr8guwqrdqeexm&redir_esc=y#v=onepage&q=%5b16%5d%09d.%20tiab%20and%20e.%20c.%20donaldson%2c%20petrophysics%3a%20theory%20and%20practice%20of%20measuring%20reservoir%20rock%20and%20fluid%20transport%20properties.%20gulf%20professional%20publishing%2c%202015.&f=false https://heinonline.org/hol/landingpage?handle=hein.journals/unlvgalj10&div=5&id=&page= https://heinonline.org/hol/landingpage?handle=hein.journals/unlvgalj10&div=5&id=&page= https://doi.org/10.2118/18166-ms https://hrcak.srce.hr/6775 https://hrcak.srce.hr/6775 https://hrcak.srce.hr/6775 https://hrcak.srce.hr/6775 https://onepetro.org/armausrms/proceedings-abstract/arma06/all-arma06/116085 https://onepetro.org/armausrms/proceedings-abstract/arma06/all-arma06/116085 https://onepetro.org/armausrms/proceedings-abstract/arma06/all-arma06/116085 https://onepetro.org/armausrms/proceedings-abstract/arma06/all-arma06/116085 https://onepetro.org/armausrms/proceedings-abstract/arma06/all-arma06/116085 https://onepetro.org/armausrms/proceedings-abstract/arma06/all-arma06/116085 https://doi.org/10.1088/1742-2132/10/5/055003 https://doi.org/10.2118/946219-g https://doi.org/10.2118/56017-pa https://doi.org/10.2118/96918-ms https://doi.org/10.2118/111286-ms z. a. mahdi and g. m. farman / iraqi journal of chemical and petroleum engineering 24,1 (2023) 125 136 134 [27] d. j. ford, “the challenges of observing geologically: third graders’ descriptions of rock and mineral properties,” sci. educ., vol. 89, no. 2, pp. 276–295, 2005, https://doi.org/10.1002/sce.20049. [28] b. hughes, “introduction to wireline log analysis,” bak. atlas, 2002. [29] s. a. shedid and m. a. saad, “comparison and sensitivity analysis of water saturation models in shaly sandstone reservoirs using well logging data,” j. pet. sci. eng., vol. 156, pp. 536–545, 2017, https://doi.org/10.1016/j.petrol.2017.06.005. [30] c. barros and a. andrade, “determination of water saturation by intelligent algorithm,” iii simbgf, 2008. [31] j. r. fanchi, principles of applied reservoir simulation. elsevier, 2005. [32] s. tandon, c. newgord, and z. heidari, “wettability quantification in mixed-wet rocks using a new nmrbased method,” spe reserv. eval. eng., vol. 23, no. 03, pp. 896–916, 2020, https://doi.org/10.2118/191509-pa. [33] w. h. nugent, g. r. coates, and r. p. peebler, “a new approach to carbonate analysis,” spwla 19th annual logging symposium, 1978. [34] i. odizuru-abangwu, a. suleiman, and c. nwosu, “the impact of different shaly sand models on in place volumes and reservoir producibility in niger delta reservoirs-the dual water and normalized waxman-smits saturation models,” nigeria annual international conference and exhibition, 2010, https://doi.org/10.2118/140627-ms. [35] h. daigle, b. ghanbarian, p. henry, and m. conin, “universal scaling of the formation factor in clays: example from the nankai trough,” j. geophys. res. solid earth, vol. 120, no. 11, pp. 7361–7375, 2015, https://doi.org/10.1002/2015jb012262. [36] d. j. hartmann, e. a. beaumont, and n. h. foster, “predicting reservoir system quality and performance,” explor. oil gas traps aapg treatise pet. geol. handb. pet. geol., pp. 1–9, 1999. [37] y. kuang, l. sima, z. zhang, z. wang, and m. chen, “a model for estimating the saturation exponent based on nmr in tight sandy conglomerate reservoirs,” arab. j. sci. eng., vol. 43, no. 11, pp. 6305–6313, 2018, https://doi.org/10.1007/s13369017-3013-1. [38] m. el-bagoury, “integrated petrophysical study to validate water saturation from well logs in bahariya shaley sand reservoirs, case study from abu gharadig basin, egypt,” j. pet. explor. prod. technol., vol. 10, no. 8, pp. 3139–3155, 2020, https://doi.org/10.1007/s13202-020-00969-3. [39] d. v ellis and j. m. singer, well logging for earth scientists, vol. 692. springer, 2007, https://doi.org/10.1007/978-1-4020-4602-5. [40] s. deng, q. sun, h. li, n. huo, and x. he, “the sensitivity of the array resistivity log to mud filtrate invasion and its primary five-parameter inversion for improved oil water recognition,” pet. sci., vol. 9, no. 3, pp. 295–302, 2012, https://doi.org/10.1007/s12182-012-0212-y. [41] r. f. aguilera, “a triple porosity model for petrophysical analysis of naturally fractured reservoirs,” petrophysics-the spwla j. form. eval. reserv. descr., vol. 45, no. 02, 2004. [42] k. yazdchi, s. srivastava, and s. luding, “on the validity of the carman-kozeny equation in random fibrous media,” in particles ii: proceedings of the ii international conference on particle-based methods: fundamentals and applications, pp. 264– 273, 2011. [43] c. haro, “the theory behind the carman–kozeny equation in the quest for permeability of the rocks,” geoconvention integr. 5th–10th may, calgary, canada, 2013. [44] m. p. tixier, “evaluation of permeability from electric-log resistivity gradients,” oil gas j., vol. 16, pp. 113–133, 1949. [45] w. l. watney, j. h. doveton, and w. j. guy, “development and demonstration of an enhanced spreadsheet-based well log analysis software. final report, may 1998,” kansas geological survey, lawrence, ks (united states), 1998, https://doi.org/10.2172/296691. [46] n. e. stauff, k. biegel, w. n. mann, and b. dixon, “feb. 2021 electricity blackouts and natural gas shortages in texas,” argonne national lab.(anl), argonne, il (united states), 2021. [47] d. h. gray and i. fatt, “the effect of stress on permeability of sandstone cores,” soc. pet. eng. j., vol. 3, no. 02, pp. 95–100, 1963, https://doi.org/10.2118/531-pa. [48] m. abdideh, n. b. birgani, and h. amanipoor, “estimating the reservoir permeability and fracture density using petrophysical logs in marun oil field (sw iran),” pet. sci. technol., vol. 31, no. 10, pp. 1048–1056, 2013, https://doi.org/10.1080/10916466.2010.536806. [49] s. cannon, petrophysics: a practical guide. john wiley & sons, 2015. [50] r. l. thomas, h. a. nasr-el-din, j. d. lynn, s. mehta, and s. r. zaidi, “precipitation during the acidizing of a ht/hp illitic sandstone reservoir in eastern saudi arabia: a laboratory study,” spe annual technical conference and exhibition, 2001, https://doi.org/10.2118/71690-ms. [51] g. zhiye and h. qinhong, “estimating permeability using median pore-throat radius obtained from mercury intrusion porosimetry,” j. geophys. eng., vol. 10, no. 2, p. 25014, 2013, https://doi.org/10.1088/1742-2132/10/2/025014. https://doi.org/10.1002/sce.20049 https://doi.org/10.1016/j.petrol.2017.06.005 https://books.google.iq/books?hl=en&lr=&id=lyedwvqe1_yc&oi=fnd&pg=pr1&dq=%5b31%5d%09j.+r.+fanchi,+principles+of+applied+reservoir+simulation.+elsevier,+2005.&ots=jnx7kwyipz&sig=izjmyk6q6a5xdh1lq-dvsakarbo&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=lyedwvqe1_yc&oi=fnd&pg=pr1&dq=%5b31%5d%09j.+r.+fanchi,+principles+of+applied+reservoir+simulation.+elsevier,+2005.&ots=jnx7kwyipz&sig=izjmyk6q6a5xdh1lq-dvsakarbo&redir_esc=y#v=onepage&q&f=false https://doi.org/10.2118/191509-pa https://onepetro.org/spwlaals/proceedings-abstract/spwla-1978/all-spwla-1978/spwla-1978-o/19848 https://onepetro.org/spwlaals/proceedings-abstract/spwla-1978/all-spwla-1978/spwla-1978-o/19848 https://onepetro.org/spwlaals/proceedings-abstract/spwla-1978/all-spwla-1978/spwla-1978-o/19848 https://doi.org/10.2118/140627-ms https://doi.org/10.1002/2015jb012262 https://archives.datapages.com/data/specpubs/beaumont/ch09/ch09.htm https://archives.datapages.com/data/specpubs/beaumont/ch09/ch09.htm https://archives.datapages.com/data/specpubs/beaumont/ch09/ch09.htm https://archives.datapages.com/data/specpubs/beaumont/ch09/ch09.htm https://onepetro.org/petrophysics/article-abstract/171065/a-triple-porosity-model-for-petrophysical-analysis https://onepetro.org/petrophysics/article-abstract/171065/a-triple-porosity-model-for-petrophysical-analysis https://onepetro.org/petrophysics/article-abstract/171065/a-triple-porosity-model-for-petrophysical-analysis https://onepetro.org/petrophysics/article-abstract/171065/a-triple-porosity-model-for-petrophysical-analysis http://hdl.handle.net/2117/189073 http://hdl.handle.net/2117/189073 http://hdl.handle.net/2117/189073 http://hdl.handle.net/2117/189073 http://hdl.handle.net/2117/189073 http://hdl.handle.net/2117/189073 https://www.searchanddiscovery.com/pdfz/documents/2014/41344haro/ndx_haro.pdf.html https://www.searchanddiscovery.com/pdfz/documents/2014/41344haro/ndx_haro.pdf.html https://www.searchanddiscovery.com/pdfz/documents/2014/41344haro/ndx_haro.pdf.html https://www.searchanddiscovery.com/pdfz/documents/2014/41344haro/ndx_haro.pdf.html https://cir.nii.ac.jp/crid/1571135649133465216 https://cir.nii.ac.jp/crid/1571135649133465216 https://cir.nii.ac.jp/crid/1571135649133465216 https://doi.org/10.2172/296691 https://publications.anl.gov/anlpubs/2021/07/169454.pdf https://publications.anl.gov/anlpubs/2021/07/169454.pdf https://publications.anl.gov/anlpubs/2021/07/169454.pdf https://publications.anl.gov/anlpubs/2021/07/169454.pdf https://doi.org/10.2118/531-pa https://doi.org/10.1080/10916466.2010.536806 https://books.google.iq/books?hl=en&lr=&id=p9i9cgaaqbaj&oi=fnd&pg=pp11&dq=%5b49%5d%09s.+cannon,+petrophysics:+a+practical+guide.+john+wiley+%26+sons,+2015.&ots=ieczzmkra6&sig=d1j6pfqyr08fcg-fat0t3a3zel4&redir_esc=y#v=onepage&q=%5b49%5d%09s.%20cannon%2c%20petrophysics%3a%20a%20practical%20guide.%20john%20wiley%20%26%20sons%2c%202015.&f=false https://books.google.iq/books?hl=en&lr=&id=p9i9cgaaqbaj&oi=fnd&pg=pp11&dq=%5b49%5d%09s.+cannon,+petrophysics:+a+practical+guide.+john+wiley+%26+sons,+2015.&ots=ieczzmkra6&sig=d1j6pfqyr08fcg-fat0t3a3zel4&redir_esc=y#v=onepage&q=%5b49%5d%09s.%20cannon%2c%20petrophysics%3a%20a%20practical%20guide.%20john%20wiley%20%26%20sons%2c%202015.&f=false https://doi.org/10.2118/71690-ms https://doi.org/10.1088/1742-2132/10/2/025014 z. a. mahdi and g. m. farman / iraqi journal of chemical and petroleum engineering 24,1 (2023) 125 136 135 [52] b. balan, s. mohaghegh, and s. ameri, “state-ofthe-art in permeability determination from well log data: part 1-a comparative study, model development,” spe eastern regional meeting, 1995, https://doi.org/10.2118/30978-ms. [53] b. shen, d. wu, and z. wang, “a new method for permeability estimation from conventional well logs in glutenite reservoirs,” j. geophys. eng., vol. 14, no. 5, pp. 1268–1274, 2017, https://doi.org/10.1088/1742-2140/aa7798. [54] w. t. mackenzie, “petrophysical study of the cardium sand in the pembina field,” fall meeting of the society of petroleum engineers of aime, 1975, https://doi.org/10.2118/5541-ms. [55] p. khodaei, s. karimpouli, m. balcewicz, and e. h. saenger, “computing wave velocity of rock sample using rock chips and cuttings,” j. pet. sci. eng., vol. 209, p. 109849, 2022, https://doi.org/10.1016/j.petrol.2021.109849. [56] p. f. worthington and l. cosentino, “the role of cutoffs in integrated reservoir studies,” spe reserv. eval. eng., vol. 8, no. 04, pp. 276–290, 2005, https://doi.org/10.2118/84387-pa. [57] j. jensen, l. w. lake, p. w. m. corbett, and d. goggin, statistics for petroleum engineers and geoscientists, vol. 2. gulf professional publishing, 2000. [58] g. w. gunter, d. r. spain, e. j. viro, j. b. thomas, g. potter, and j. williams, “winland pore throat prediction method-a proper retrospect: new examples from carbonates and complex systems,” spwla 55th annual logging symposium, 2014. [59] n. bouffin, “net pay evaluation: a comparison of methods to estimate net pay and net-to-gross ratio using surrogate variables.” texas a & m university, 2010. [60] p. masoudi, b. arbab, and h. mohammadrezaei, “net pay determination by dempster rule of combination: case study on iranian offshore oil fields,” j. pet. sci. eng., vol. 123, pp. 78–83, 2014, https://doi.org/10.1016/j.petrol.2014.07.014. https://doi.org/10.2118/30978-ms https://doi.org/10.1088/1742-2140/aa7798 https://doi.org/10.2118/5541-ms https://doi.org/10.1016/j.petrol.2021.109849 https://doi.org/10.2118/84387-pa https://books.google.iq/books?hl=en&lr=&id=mhf_petbfbic&oi=fnd&pg=pr5&dq=%5b57%5d%09j.+jensen,+l.+w.+lake,+p.+w.+m.+corbett,+and+d.+goggin,+statistics+for+petroleum+engineers+and+geoscientists,+vol.+2.+gulf+professional+publishing,+2000.&ots=su0m68u280&sig=acipbvhfx8h5gr4vuy2uorwts10&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=mhf_petbfbic&oi=fnd&pg=pr5&dq=%5b57%5d%09j.+jensen,+l.+w.+lake,+p.+w.+m.+corbett,+and+d.+goggin,+statistics+for+petroleum+engineers+and+geoscientists,+vol.+2.+gulf+professional+publishing,+2000.&ots=su0m68u280&sig=acipbvhfx8h5gr4vuy2uorwts10&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=mhf_petbfbic&oi=fnd&pg=pr5&dq=%5b57%5d%09j.+jensen,+l.+w.+lake,+p.+w.+m.+corbett,+and+d.+goggin,+statistics+for+petroleum+engineers+and+geoscientists,+vol.+2.+gulf+professional+publishing,+2000.&ots=su0m68u280&sig=acipbvhfx8h5gr4vuy2uorwts10&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=mhf_petbfbic&oi=fnd&pg=pr5&dq=%5b57%5d%09j.+jensen,+l.+w.+lake,+p.+w.+m.+corbett,+and+d.+goggin,+statistics+for+petroleum+engineers+and+geoscientists,+vol.+2.+gulf+professional+publishing,+2000.&ots=su0m68u280&sig=acipbvhfx8h5gr4vuy2uorwts10&redir_esc=y#v=onepage&q&f=false https://onepetro.org/spwlaals/proceedings-abstract/spwla14/all-spwla14/28318 https://onepetro.org/spwlaals/proceedings-abstract/spwla14/all-spwla14/28318 https://onepetro.org/spwlaals/proceedings-abstract/spwla14/all-spwla14/28318 https://onepetro.org/spwlaals/proceedings-abstract/spwla14/all-spwla14/28318 https://onepetro.org/spwlaals/proceedings-abstract/spwla14/all-spwla14/28318 https://oaktrust.library.tamu.edu/bitstream/handle/1969.1/etd-tamu-1953/bouffin-thesis.pdf?sequence=1&isallowed=y https://oaktrust.library.tamu.edu/bitstream/handle/1969.1/etd-tamu-1953/bouffin-thesis.pdf?sequence=1&isallowed=y https://oaktrust.library.tamu.edu/bitstream/handle/1969.1/etd-tamu-1953/bouffin-thesis.pdf?sequence=1&isallowed=y https://oaktrust.library.tamu.edu/bitstream/handle/1969.1/etd-tamu-1953/bouffin-thesis.pdf?sequence=1&isallowed=y https://doi.org/10.1016/j.petrol.2014.07.014 z. a. mahdi and g. m. farman / iraqi journal of chemical and petroleum engineering 24,1 (2023) 125 136 136 تطور الطرق المستخدمة لتقيم الخواص البتروفيزيائيةمراجعة لمراحل غانم مديح فرمانو * زهراء أياد مهدي قسم هندسة النفط، كلية الهندسة، جامعة بغداد، العراق الخالصة ع طرق ، ويشمل جمياالبار النفطية المحفورة سنة في 50تحليل التكوينات الجوفية بدأ تطبيقه قبل اكثر من ذات والنتائج المختبرية ساسات الجسوالتسجيل واالختبار وأخذ العينات بشكل عام. حيث يتم مناقش قيالحفر ه ، بما في ذلك إلقاء نظرة على عينات السوائل التي تم اخذها من هذلصلة بتقييم التكوينات تحت السطحا لى إاء" مصطلح يستخدم لإلشارة لتعريف مصطلح "البتروفيزي .رمن أجل تقييم التكوينات بدقة أكب التكوينات ا كون منهاألكبر التي تت أنظمة الصخور ، بينما تتعلق الجيوفيزياء بفيزيائيةأنواع معينة من الصخور فيزيائية ة فيزيائيعلم البتروفيزيائية للصخور المكمنية هو العلم الذي يركز على دراسة الخصائص الكيميائية وال األرض. ت . خالل السنواالمسؤولة عن توزيع المسام والسوائل المكمنية المكونة للصخورللوسط المسامي والعناصر ، يد من الدراسات حول خصائص الصخور، مثل المسامية، والنفاذية، والضغط الشعري ، تم إجراء العداألخيرة عاعي اإلش لنشاط، واوالتشبع الهيدروكربوني، وخصائص السوائل، والمقاومة الكهربائية، والجهد الذاتي أو الطبيعي ن ألنواع مختلفة من الصخور. ُتستخدم هذه الخصائص وعالقاتها لتقييم وجود أو عدم وجود كميات تجارية م و هالهيدروكربونات في التكوينات التي تم اختراقها أو تقع بالقرب منها. الغرض الرئيسي من هذا البحث ل بناءً لحساب خصائص البتروفيزياء في المختبر والحقو مراجعة تاريخ تطور التقنيات األكثر شيوًعا المستخدمة .العلماء و الباحثين في هذا المجالعلى خبرة .، تفسيرتقنيات نفطية ،نفاذية ،مسامية، تشبع مائي، مكمن ،حجم السجيل ،هايدروكاربون ،الخواص البتروفيزيائية :دالةالكلمات ال iraqi journal of chemical and petroleum engineering vol.13 no.3 (september 2012) 1734 issn: 1997-4884 increasing of oil field productivity by implementation of re-entry horizontal injection well, case study ghazwan.n.jreou university of kufa– college of engineering, iraq abstract water flooding is one of the most important methods used in enhanced production; it was a pioneer method in use, but the development of technology within the oil industry, takes this subject toward another form in the oil production and application in oil fields with all types of oils and oil reservoirs. now days most of the injection wells directed from the vertical to re-entry of full horizontal wells in order to get full of horizontal wells advantages. this paper describes the potential benefits for using of re-entry horizontal injection wells as well as combination of re –entry horizontal injection and production wells. al qurainat productive sector was selected for study, which is one of the four main productive sectors of south rumaila oil field. a simulation model – named as srfq was used in the present work to predict the re-entry horizontal wells performance. four scenarios were suggested to cover the full scope of the study; those scenarios are different in manner of wells combinations. cumulative oil production, ultimate recovery percentage are two criteria were used to predict the performance and comparison of scenarios. results from simulation model (srfq) runs revealed that the productive sector can be continue to gain 1564.331 mmstb till 2020, without changing to any existing injection and production wells status, which is called the base scenario. while scenario no.1 needs some of work over and remedies jobs, which gives more cumulative oil production reaches to 1698.481 mmstb till 2020. on another side, scenarios no. 2 and 4 are the most important scenarios because reentry horizontal injection wells were implemented. very good and encourage results were gained over the bas scenario from the sector under study. at last, scenario no.3 was suggested just to predict the production capacity of the al qurainat sector with re-entry horizontal production wells and existing vertical injection and production wells, while the cumulative oil production reaches 3398.481mmstb. key words: horizontal, reservoir management, increasing production, re-entry. introduction it is well known that water injection is the most common method for increasing oil recovery and pressure maintenance applications, where water injection is often used as a recovery method for light oil reservoirs, then latterly was used for viscous oil iraqi journal of chemical and petroleum engineering university of baghdad college of engineering increasing of oil field productivity by implementation of re-entry horizontal injection well, case study 18 ijcpe vol.13 no.3 (september 2012) -available online at: www.iasj.net reservoirs by martini, r.f.et al.(2005) 1 . this oil recovery technique becomes an increasing important issue in the management of produced fluids, including disposal or produced water as well as oil from production or field. water flooding technology was developed along the time from the forties of the previous century up to now. now a days the use of horizontal wells within eor applications becomes traditional and have been increasing very rapidly through the oil industry as advances in drilling techniques continue to overcome water flooding problems like sweep efficiency, oil production with high wor, front shape, injection flow rate,....etc. most of the recent reports or publications appeared the interesting of horizontal-well water flooding starting from the nineties decade of the last century, although there are relatively little published information about the using of horizontal water injection wells in comparison with another recovery methods. the need for injection patterns of both horizontal injection and production wells, opposed vertical fractures well placement, are necessary for increasing the rate of flooding in eor processes. however, in spite of the tremendous increase in literature reference, little information is available on horizontal well application for eor methods. a survey of extensive horizontal well literature is beyond the scope of this paper, but reviews of books, spe reprint series and published articles, show that horizontal wells are still used primarily to solve specific production problems, which includes 2 : low permeability formation, specially fractured formations. low permeability gas reservoir. unusual gas resources such as coalbed methane or devonian shale. gas or water coning. thin formation. viscous oil. the development of oil and gas fields take a variety of pictures and forms, depending on the circumstances and productivity associated with hydrocarbon reservoirs. in addition to that, the method and the application ways of strategy plans that were developed by engineers, responsibility of production techniques and reservoir management of oil and gas field. with more planning and management point of views, using of different ways and advanced technology in the implementation of production plans, the goal will be clear and deliberated with less losing and cost risk. therefore, emerged as the importance of implementing plans and reservoir management processes," which are practically relies on use of financial, technological, and human resources, while minimizing capital investments and operating expenses to maximize economic recovery of oil and gas from a reservoir" 3. the purpose of reservoir management is to control operations to obtain the maximum possible economic recovery from a reservoir on the basis of facts, information, and knowledge (4, 5, 6). this paper describes potential benefits of using re-entry horizontal injection as well as production wells for water flooding purposes in case of production enhancement and field development. incremental of cumulative production and sweep efficiency are the criteria used for comparison and improvement. southern rumail oil field 7 the dimensions of southern rumailal oil field are about 38 km long and 14 km wide. the field is associated with large gentle anticline ghazwan. n. jreou -available online at: www.iasj.net ijcpe vol.13 no.3 (september 2012) 19 fold of sub meridional trend; dip angles on the flanks do not exceed 3 ○ whereas in the crested parts they are about 1 ○ . the field main pay reservoir is divided into four production sectors, also the reservoir consists of five production units according to the differences between the porosity and the permeability, which are from top to bottom r1, r2.1, r2.2, r3.1 and r3.2 respectively. the field is surrounded by a large aquifer and the predominate production driving force is the natural water drive which is active as driving force and contribute up to 90% (8,9,10) of the production energy. the problem in the reservoir under study is the asymmetric rising of oil water contact on east & west flanks, which means that the reservoir has a tilted owc because of unequal water influx advancement in both sides of the field. in accordance to that, the water will spill over from the west flank to the east part of the reservoir. to prevent the spillover phenomenon, the reservoir engineering directorate executed the water injection project along the east flank of the field in order to support the reservoir pressure decline and balance the fast water advancement from the west side of the field. many development stages had been carried out along the production life of the field since exploration, which were executed in sequence of development stages. the wells have a high production potential, some of them reach up to 50,000 stb/d at the early time of production life. many reservoir studies (11, 12) outlined that the recovery factor for all reservoir units (r1, r2, r3) in southern rumaila field could not be below 50%. therefore, the most reasonable value of recovery factor in the field is 54% and the ooip will be 1458 mm tons. the production from the field reaches to 65 mm tons/ year and can be held on this level of production by water injection in addition water drive. the reservoir behavior (production, injection, pressure, water advancement) is directly and frequently investigated by the engineers in order to ensure that the application of production plan to reach high production rates with good depletion strategies. geological description the main pay reservoir in south rumailaoil field is one of the most important and prolific oil producing reservoirs in southern area of iraq. this reservoir constitutes the upper sandstone member of the zubair formation that is called main pay zone of south rumaila oil field. the zubair formation in south of iraq found in (rumaila, west qurna and zubair fields), which belongs to the depositional cycle of lower parremian of lower cretaceous age .the formation is generally, composed of sandstone and shale. the ratio of sand in the formation decreases significantly toward the east while this ratio increases toward the west and it may reach to 100% in the west of south rumaila oil field. the sand ratio also decreases toward the north while it increases to the south. zubair formation has been divided into five members on the basis of sand to shale ratio. the main pay (upper sand stone member) comprises three dominated sandstone units, separated by two shale units. the shale units act as good barriers impeding vertical migration of the reservoir fluids except in certain areas where they disappear. for more details with geological description of main pay reservoir can be found in reference [7]. increasing of oil field productivity by implementation of re-entry horizontal injection well, case study 20 ijcpe vol.13 no.3 (september 2012) -available online at: www.iasj.net the main pay is an important producing horizon; even though, it is considered being in a mature stage of depletion due to highly water advancement over some parts of it. in spite of that a large cumulative production from the main pay reservoir still continue, and the oil recovery during the primary production stage affected by the un balance water drive from the both sides of the field. water flooding in south rumaila oil field in an attempt to increase the production of oil from the main pay reservoir and maintain the reservoir pressure by achieving better water injection plan, a water flooding project was implemented from 1980 up to now, through multi stages of completion along the field life. problems have been appeared at the beginning of water flooding project like un stable water injection flow rate, decreasing of formation ability to receive the injected water quantity with the time, diminished and lack in amount of water injected to the producing layers ...etc. therefore, one can see unfavorable water flooding operations within the field and much oil still remaining in reservoir, especially in the upper parts of main pay reservoir. why horizontal well water flooding? (13-18) in the last few years, the number of horizontal wells drilled has substantially increased worldwide. the gained field results published in papers and reports are revealed, that the application of horizontal wells are encourageous, so that the major advantages of using horizontal wells are increasing productivities, minimizing gas and water coning, extending areal sweep, and connecting vertical fractures. martkitell and huang(1993) 14 stated that to drill a successful and economical horizontal well for a specific reservoir requires state-of-theart for drilling/completion techniques, a detailed geologic/reservoir description study, and an optimal well design. the horizontal well design involves many aspects such as well length, location relating to goc/woc, spacing, and performance prediction compared to a vertical well, in addition to the technical objective of the horizontal well is to expose significantly more reservoir rocks to the well bore surface than can be achieved via drilling of a conventional vertical wells, so the desire to achieve this objective stems from the intended achievement of others. more important technical objectives that relate to the specific characteristics of the target reservoir are related to the more objectives (avoidance of water production for example) achieved by desire horizontal wells which provides an economic benefits. the drilling, completion and production techniques have been modified for the horizontal environment; this lead to the average cost is going down. additionally, the key issues in correct application of horizontal wells technology pivots around achieving desired production/ injection of the project wells and the cost associated with drilling horizontal wells without damaging the depleted and low pressure reservoir. southern rumaila field development most of the explored oil and gas fields, after completing of the exploratory drilling phase to identifying the reservoir limits, and make sure the hydrocarbon inventory. the professional engineering staff of the reservoir management and fields ghazwan. n. jreou -available online at: www.iasj.net ijcpe vol.13 no.3 (september 2012) 21 development directorate, beginning to prepare the reservoir studies for the development purposes in order to put the reservoir under commercial production with optimum exploitation of its natural energy by using of optimum production methods. hydrocarbon fluids must be withdrawal from the reservoir without loosing of reservoir energy, so the complete process seems like balancing between fluids withdrawal and reservoir pressure drops. with progressing of oil field production, there are many production plans were suggested, discussed and implemented according to the production of h.c quantitiesand accompanied reservoir pressure draw down. the main pay reservoir in south rumaila oil field was developed since early times of production up to now with different stages (19) ,these stages are out of the scope of the present work. this work presenting, a new idea of development for the qurainat production sector by suggestion of a new re-entry horizontal injection wells project. principally every project success depends on careful monitoring/surveillance and through going evaluation of its performance toward the reactive agreement with the expected performance, unless the original plan should be revised and recycle again. traditionally, translating of any idea to the application phase, a process of comprehensive management plan which involves depletion and development strategies, data acquisition and analysis, geological and numerical model studies, production and reserves forecasts, knowledge of facilities requirements, economic optimization, and management approval should be performed. therefore the whole concept idea of the present work and the results derived from them, are submitted to the executive operators of the south rumaila oil field, as an application of horizontal well technology for the both of the discovery and production development stages of oil reservoir, which becomes a frequent worldwide event over the past few years, and becomes the needs for the enhancing recovery from the vast amount of the remaining oil and gas in place around the world, and to complete globally requirement of better reservoir management practices. suggestion of horizontal water flooding wells in southern rumaila oil field the south rumaila field is divided into four production sectors. from the north to the south, the sectors are qurainat, shamiya, rumaila, and janubia as in fig.1. the selection of this productive sector is due to the following reasons:  the amount of original oil in place still huge in comparison with other productive sectors.  there is a possibility in the development of this production sector from the field in terms of: the type and the number of wells. the quality of their high productivity as in the rest of the production sectors in the field. horizontal water injection wells for water flooding applied in the present work includes re-entry horizontal injection wells, besides the existing of vertical injection and production wells operate in the same productive sector. also a re-entry horizontal producing wells were suggested for production boosting from the same productive sector in some suggested cases. practically, the concept is that large volumes of water can be injected at pressure below the fracturing pressure increasing of oil field productivity by implementation of re-entry horizontal injection well, case study 22 ijcpe vol.13 no.3 (september 2012) -available online at: www.iasj.net of reservoir. using of horizontal well is attempting to demonstrate the economic impact of horizontal well for water flooding in an area adjacent to a pre-existing vertical water flood. in addition to that, thinking of horizontal water injection project needs to understand the available and adequate surface and subsurface infrastructure construction facilities, also balancing between the expenditures for equipment upgrade, drilling and completion of re-entry horizontal injection wells, injected water treatment process and volumes with how much oil can be produced?. that is, what had said before, is the view point of the field development, specially for the productive sector – qurainat of the considering field. this development perspective preceded by a descriptive study of the considered region, as well as the collection of data from the vertical wells that were currently operation within the field, to identify a suitable un-flood area within the field, then all the information are plugging in the simulation model to study the horizontal water flooding performance over the existing conventional wells. srfq simulation model the results of the present work was obtained from the reservoir simulation model called (srfq), these are classified in to two main groups, simulation results and predicted results, where the second one divided into four scenarios. simulation model building and matching are out of the scope of the present work, just taking of simulation results to help with the prediction phase of the study. runs were conducted to confirm the suitability of re-entry horizontal water injection wells for water flooding, and to verifying the main target of the present research work that is study increasing of oil productivity from qurainat productive sector of the southern rumaila oil field by proposing re-entry horizontal injection wells. the history match phase of the study was over the period from 1954 to the end of 2006. for more details about this phase of the study, one can refer to reference [10], and then the model runs from 2007 to end of 2010 according to field production conditions and facilities founded during this period. fluid saturation distribution map was obtained 10 , especially for water saturation sw-map of the concern productive sector. fig. (2a, 2b), show the saturation distribution map of the concerned sector. predictive phase results table 1, reflects the methodology that was followed by this part of the work results, so it shows there are four main scenarios suggested with the qurainat productive section of southern rumaila field. some questions were raised through the suggested re-entry horizontal injection wells, these are: 1. what are the lengths of the new reentry horizontal wells?, and where will be locate in the field?. 2. how much cumulative production can be gained from each one? 3. what are the constraints for the production from the new re-entry wells? the present study could not concern with the optimum length or location of re-entry injection wells, but studied the subject by virtue of production enhancement. field constraints are: a) production well is plugging with maximum water cut 50%. b) maximum gas oil ratio is 775 scf/stb. c) minimum bottom hole following pressure = 2660+50 pisa, where pb is 2660 psia, in order to avoid any free gas liberation. ghazwan. n. jreou -available online at: www.iasj.net ijcpe vol.13 no.3 (september 2012) 23 d) maximum bottom hole injection pressure is 6000 pisa, in order to not overcome the fracture rock pressure. prediction phase falls into four scenarios; each one had been run with srfq model from 2011 to end of 2020, so the priority of this part is to study the implementation of re-entry injection wells from existing vertical injection wells and steering them toward the right areas, also a re-entry of horizontal production wells were suggested for production boosting, taking into account the current wells status, which may be classified into: 1. ceased flow wells. 2. transferred to upper shale layer. 3. wells with fluctuation in production history due to production problems like high water cut, needs more work over jobs, low bottom hole pressure …etc. 4. limit and/or varying in receive amount of injected water by reservoir producing units across the perforated area of the injection wells, this reason depends on their petrophysical properties along the field, as well as the well capacity for injectivity. base scenario in the base scenario, the locations, production and injection rates of the existing vertical wells were fixed according to the last production schedules of 2010. prediction runs were carried out from 2011 to 2020. this scenario was done in order to confirm the following issues:  study the possibility of the qurainat production sector in southern rumaila oil field continue to produce at a rate of 0.4285 mm stb/d as minimum.  creating a base scenario for comparison with following suggested scenarios. general marks according to the following suggested scenarios, the benefit of each one will be inspecting to confirm the following items:  increasing of cumulative oil production from the productive sector under study.  study the pressure drawdown behavior along the wells production life. table 1, the outline of the prediction scenarios of the present study prediction scenario vertical injectors vertical injector with remedies. re-entry horizontal injectors vertical producers with remedies vertical producer s re-entry horizontal producers base scenario * * scenario no.1 * * scenario no.2 * * scenario no.3 * * * scenario no.4 * * * increasing of oil field productivity by implementation of re-entry horizontal injection well, case study 24 ijcpe vol.13 no.3 (september 2012) -available online at: www.iasj.net  verifying of water injection importance for the pressure maintenance in connection with natural aquifer support.  water flooding behavior and sweep efficiency under the concerning condition of each scenario. scenario no.1 this scenario has reserved with the same vertical production and injection wells, but depends on making some remedies, for those wells suffering from fluctuation in their behavior in order to increase the injection and production flow rates for them. this scenario studied the benefits of new flow rates of the existing vertical wells to confirm the general remarks. work over process with some of injection and production wells that were suffered from working problems, especially cease flow due to decreasing of formation permeability, or mechanical problems along well strings ...etc. figure 3a, shows the location of these wells. scenario no.2 this scenario introducing the re-entry horizontal injection wells with most appropriate injection flow rates favorite injection flow rate that increasing of productivity along time of prediction with less wc% measured in production wells and closing of all existing vertical injection wells, while the vertical production wells still producing under the same wells conditions of the scenario no.1. this scenario suggested confirming the importance of horizontal re-entry water injectors, in addition to the general marks. scenario no.3 this scenario is the same as scenario no.1, but with introducing of new reentry horizontal production wells with most appropriate production rates that make them continue in production under the constraint limit(wc=50%). this scenario depends on vertical injection wells under new conditions as in scenario no.1. it is suggested to confirm the production enhancements (dual producers view of point ), by introducing of re-entry horizontal production wells accompanies with existing of vertical injection and production wells as in scenario no.1, in addition to the general remarks of suggested scenarios. scenario no.4 this scenario is the same as scenario no.2, but with introducing of new reentry horizontal production wells, with most appropriate production rates that make them continue with production under the constraint limit(wc=50%). this scenario depends on re-entry horizontal injection wells under new conditions as in scenario no.2, and closing all of the vertical existing injection wells. this scenario suggested confirming the production enhancement (dual producers) with introducing of re-entry horizontal injectors as in scenario no.2, in addition to the general remarks of suggested scenarios. figure 3b, shows the suggested location of new re-entry horizontal wells. discussion of the scenarios results in this section, discussions of the suggested scenarios results are oriented to cover the guide line features, which are: 1. increasing percentage of cumulative field production. 2. the formation pressure, due to variance of pressure supporting, especially within the re-entry injection horizontal wells. 3. well pressure variation with the time. 4. production plateau ghazwan. n. jreou -available online at: www.iasj.net ijcpe vol.13 no.3 (september 2012) 25 the final results tables presented for each scenario, reflects the final results after discard the wells with low production rates ( ≤ 500 stb/d), or suffering from rapid increasing of water cut during their production life and gaining low cumulative oil production. scenario no.1 this scenario begins with identification of locations which have high production possibility. inspection the necessary of existing vertical production and injection wells within productive sector , considering of work over process advantages for each well in case. results obtained from the predictive runs of this scenario revealed that, more of oil production gaining was happen under new wells conditions. a comparison was made between scenario no.1 and base case, to inspect the validity of the production enhancement. fig. 4 shows these results in comparison with base scenario for the wc up to 50%. following are some advantages gained from this scenario, these are: 1. significantly, there is increasing of cumulative oil production, the cumulative oil recovered during the period from 2011 to 2020 is 1698.5 mmstb, in comparison with 1564.33mmstb by the base scenario. the incremental percentage increase in production is equal to 15.629% with ultimate recovery percentage reach to 39.46%. 2. the block pressure of the main pay reservoir still above the bubble point pressure. 3. the pressure supporting energy in this scenario is both of aquifer and water injection wells, but they couldn’t equally in response with cumulative fluid withdrawal from the sector, therefore a pressure declination is observed with continuing production of the wells up to the end of the predictive period. scenario no. 2 this scenario dealing with introducing of re-entry horizontal injection wells with identification of them locations from the existing vertical wells, the suggested re-entry injectors are implemented by the model srfq, while the vertical production wells are still under their conditions of scenario no.1 and close all the vertical injectors. fig. 3b, shows the new wells on gridding map of the considered productive sector (qurainat). many runs were carried out in order to gain more oil production. an appropriate injection rates according to sweep efficiency were applied for those injectors. fig.5 shows the comparison with base scenario, to inspect the validation of production enhancement by introducing those new re-entry injection wells. the gained results from this scenario revealed the following advantages: 1. increasing of field oil production significantly. the cumulative oil recovered during the period from 2011 to 2020 is 2118.14mmstb, in comparison with 1564.334mmstb by the base scenario. the incremental percentage in production is equal to 26.15% with ultimate recovery percentage reach to 49.21%. 2. high cumulative production from existing vertical wells by this scenario in comparison with base vertical production wells. 3. the block pressure of the main pay reservoir still above the bubble point pressure. increasing of oil field productivity by implementation of re-entry horizontal injection well, case study 26 ijcpe vol.13 no.3 (september 2012) -available online at: www.iasj.net scenario no. 3 this scenario is similar to scenario no.1 with proposing of a new re-entry horizontal production wells to boost the production concerning the same water cut limit. results of re-entry horizontal wells of this scenario can be seen in the table 2, which presents the production rate and cumulative oil production for both dry and wet oil. a comparison was made with the base scenario to insure the improvement in cumulative oil production, fig. 6 shows these results. the final results of this scenario by introducing of new reentry wells can explain the cumulative oil production improvement as following: 1. cumulative oil production recovered during the period from 2011 to 2020, is 3398.481mmstb, in compariso 2. n with 1564.33mmstb by the base scenario. the incremental percentage in production is equal to 23.629% with ultimate recovery percentage reach to 78.96%. it seems there was almost big difference relative to the base case. 3. high cumulative production from those new re-entry wells were gained in comparison with their existing vertical production wells. 4. still the block pressure of the productive regions above the bubble point pressure. the pressure maintenance in this scenario is aquifer and water injection wells together. table 2, production schedule for re-entry horizontal production wells in scenario no.3 well no. productio n rate (stb/d) date to end of dry oil production cumulative production of dry oil (mmstb) well status at the end of prediction cumulative production wet oil (mmstb) 400 5000 ---- 31.12.2020 49% 18.25 401 2000 6.9.2013 1.958 2.4.2017 48% 4.564 402 2000 ----31.10.2016 4.258 403 500 neglected 404 3000 16.1.2014 3.333 31.12.2020 41% 7.617 405 3000 ---- 31.12.2020 41% 10.95 406 500 neglected 407 2500 ---- 30.6.2020 49% 8.665 408 500 neglected 409 500 neglected 410 5000 31.10.2017 12.47 31.12.2020 46% 18.25 411 3000 31.12.2020 10.95 310.12.202 0% 10.95 412 3000 28.7.2013 2.817 31.12.2020 42% 10.95 ghazwan. n. jreou -available online at: www.iasj.net ijcpe vol.13 no.3 (september 2012) 27 scenario no.4 this scenario is similar to scenario no.2 with proposing of a new re-entry horizontal production wells. the improvement of oil production within the concerning productive sector within this scenario has been gotten with the same water cut constraint. results of the re-entry horizontal production wells of this scenario can be seen in the table 3, which presents the production rate and cumulative oil production for both dry and wet oil. a comparison was made with the base scenario to insure the improvement in cumulative oil production by this scenario, fig. 7, shows these results. the final results of this scenario by introducing of new reentry wells can explain the cumulative oil production improvement as following: 1. cumulative oil production recovered during the period from 2011 to 2020 is 3364.133mmstb, in comparison with 1564.33mmstb by the base scenario. the incremental percentage in production is equal to 22.629% with ultimate recovery percentage reach to 78.16%. it was shown that this scenario slightly less than the third one. 2. pressure maintenance manner, block pressure behavior (> pb ), cumulative oil production of reentry production wells follows the same explanations as in scenario no.3. figure (7), shows the comparison results with base scenario. table 3, production schedule for re-entry horizontal production wells in scenario no.4 well no. production rate (stb/d) date to end of dry oil production cumulative production of dry oil (mmstb) well status at the end of prediction cumulative production wet oil (mmstb) 400 4500 ---- 31.12.2020 44% 16.425 401 500 neglected 402 500 neglected 403 500 neglected 404 500 neglected 405 500 neglected 406 1750 ---- 31.12.2020 50% 6.3875 407 8000 ---- 31.12.2020 34% 29.2 408 500 neglected 409 500 neglected 410 4000 20.8.2015 6.768 28.2.2019 46% 11.916 411 3250 31.10.2015 5.733 14.10.2020 49% 11.609 412 3750 18.10.2012 2.46 31.1.2017 50% 8.329 increasing of oil field productivity by implementation of re-entry horizontal injection well, case study 28 ijcpe vol.13 no.3 (september 2012) -available online at: www.iasj.net final decision, which scenario is the best? at the end of the suggested scenarios results, table (4), summarize the importance of the re-entry horizontal wells implementation within qurainat production sector/ main pay reservoir. in general, all the scenarios results are encouraging to increase the sector production by re-entry wells (injection and /or production) over the base case, and this is in fact ensuring one of the horizontal wells validations in south rumaila oil field, also it can be considered as future development step point of view for this field. the suggested scenarios have different wells locations as mentioned before and demonstrated in fig. 3b, within the whole productive sector. these wells have different time of break through (assuming of wc equal 10%), and time of reaching the upper limit of 50% wc. there is no chance of locally free gas librated in production wells, or the pressure still above pb. the present study considered as development stage view point to soc company, because the south rumaila oil field is falling under its management, therefore soc may have the following choices when put this study in execution plane, and can expand the same idea to another productive sectors in the field.  according to the present status of the field production with max of 50%wc, scenario no.1 can be adopted with doing some of work over and remedies jobs for the vertical injection and production wells, in order to rehabilitate them and return them to the service. increasing of the cumulative oil production has been gotten from 1564.33 mmstb to 1698.5 mmstb along the time period from 2011 to 2020.  both of sweep efficiency and cumulative production was improved by adopting of re-entry horizontal injection wells and close all of vertical injection wells, scenario no.2.  implementation of both re-entry horizontal injection and production wells (dual producers), reveals that the cumulative oil production reach to 1665.652mmstb in scenario no.4 in comparison with base scenario for the same suggested time period. table 4, cumulative oil production and incremental percentage in comparison with base scenario cumulative oil production (2011-2020), mmstb incremental percentage in comparison with the base scenario ultimate recovery percentage reentry drilling and completion coast (million$) * base scenario 1564.3314 36.35 ---- scenario no.1 1698.481 15.629 39.46 ---- scenario no.2 2118.14 26.15 49.21 28.8 scenario no.3 3398.481 23.629 78.96 64.8 scenario no.4 3364.133 22.629 78.16 72 *re – entry drilling and completion cost calculated according to 1.2 20 times vertical well cost. **vertical well drilling and completion cost reach to 6 million dollars 21 . ghazwan. n. jreou -available online at: www.iasj.net ijcpe vol.13 no.3 (september 2012) 29 fig.1, southern rumaila oil field fig.2a, average saturation of qurainat sector, base scenario-dec.2010 fig.2b, average saturation of qurainat sector, base scenario-dec.2020 increasing of oil field productivity by implementation of re-entry horizontal injection well, case study 30 ijcpe vol.13 no.3 (september 2012) -available online at: www.iasj.net fig.3a, qurainat productive sector gridding map with production and injection wells fig.3b, qurainat productive sector gridding map with re-entry horizontal production and injection wells ghazwan. n. jreou -available online at: www.iasj.net ijcpe vol.13 no.3 (september 2012) 31 fig.4, comparison between base scenario and scenario no.1 fig.5, comparison between base scenario and scenario no.2 fig.6, comparison between base scenario and scenario no.3 increasing of oil field productivity by implementation of re-entry horizontal injection well, case study 32 ijcpe vol.13 no.3 (september 2012) -available online at: www.iasj.net fig.7, comparison between base scenario and scenario no.4 conclusions 1. the final results of the suggested scenarios in the present study are courageous for executing and implementing re-entry horizontal wells project within main pay reservoir in southern rumaila oil field according to the predicted cumulative oil production and ultimate recovery percentage by the suggested scenarios. 2. all the scenarios reveal that the reentry wells have higher capacity either for injection or production usage. good and acceptable production incremental percentage in comparison with the present existing vertical wells that were launched from them to the production units (r1, r2 and r3). 3. the production from the productive sector al qurainate – reach to 0.465 mmstb/d (scenario no.1), under the present field conditions, while the cumulative production reach to 1698.481 mmstb at the end of 2020. 4. it is clear from tables 2 and 3, the time of dry and wet oil production are different among suggested wells in each scenario or among scenarios themselves for each well, this return to the location of the new suggested re-entry wells, the directions and their proximity from the high water saturation grids. other factors may play significant effects on wells behavior like: a. the effect of the adjacent existing vertical production wells. b. the daily production rate. c. the flow capacity for the penetrated grids by those wells. acknowledgement the author gratefully acknowledges with appreciation to south oil company for their technical support and efforts to complete this study. nomenclature h.c = hydro carbon h.w = horizontal well. eor = enhanced oil recovery. gow = gas oil contact. soc = south oil company. srfq = south rumaila field (name of model). srfq = model name, southern oil field. owc = oil water contact. wc = water cut. wor = water oil ratio. ghazwan. n. jreou -available online at: www.iasj.net ijcpe vol.13 no.3 (september 2012) 33 si metric conversion factors stb x 1.589873 e-01= m 3 ft x 3.048 = m ton x 9.071847 e-01 = mg api ο 141.5/ (131.5+ api ο ) = gm/cm 3 references 1. martini, r.f., bonet, e.j.and schoizer, d.j., .water injection through horizontal well. paper spe 97740 presented at the spe/ps-cim international thermal operations and heavy oil symposium, 1-3 november 2005, calgary, alberta, canada. 2. drilling sidewaya review of horizontal well technology and its domestic application, april 1993, doe/eia – tr-0565. 3. thakur, g.c. 1995. the role of technology and decision analysis in reservoir management. paper spe 29775-ms presented at middle east oil show, 11-14 march 1995, bahrain. 4. abdus satter, james e. varnon and muu.t. 1994. hoang. integrated reservoir management. journal of petroleum technology 46 (12):1057-1064, spe 22350-pa. doi.:10.2118/22350-pa. 5. john n. ezekwe. 2003. applied reservoir management principals with case histories. paper 84148ms presented at spe annual technical conference and exhibition, 5-8 october 2003, denver, colorado. 6. daoyong yang, qi zhang, yongan gu.2002.integrated production operation models with reservoir simulation for optimum reservoir management. paper spe 75236-ms presented at spe/doe improved oil recovery symposium, 13-17 april 2002, tulsa, oklahoma. 7. al-ansari, r.: “the petroleum geology of the upper sandstone member of the zubair formation in the rumaila south” oilfield ministry of oil, dept. of reservoirs and fields development-section of production studies, jan. 1993. 8. ban, j.and th. gadban, “frontal advancement and recovery calculation for the main pay reservoir", technical report no.60, basra, 1979. 9. ban, j., a. yassar and m.noori, “frontal advancement and recovery calculation for the main pay reservoir", technical report no.205, basra, 1980. 10. ban, j., a. yassar and s. khamas, “frontal advancement and recovery calculation for the main pay reservoir", technical report no.235, basra, june-1990. 11. sameera, m.h. (1999), “modeling a sector of the main reservoir of south rumaila oil field”, ph.d. dissertation, university of baghdad. 12. mohammed, n.i, and w.s, abbas, " detailed reservoir study for southern and northern rumaila oil field/ main pay reservoir, part i1997. and part ii-1999. 13. taber, j.j., seright, r.s. 1992. horizontal injection and production wells for eor or water flooding. paper spe 23952-ms presented at permian basin oil and gas recovery conference, 18-20 march 1992, midland, texas. 14. wang, ben, marktell, b.n., huang, w.s.1993.case studies of horizontal well design and production forecast. paper spe 25567-ms presented at middle east oil show, 3-6 april 1993, bahrain. 15. reeves, s.r., strickland, t.a. and crawford, p.b. 1993.utilization of horizontal wells for secondary oil recovery. paper spe 25350-ms presented at spe asia pacific oil and gas conference, 8-10 february 1993, singapore. 16. paige, r.w.,, murray, l.r., martins, j.p., and marsh, s.m. increasing of oil field productivity by implementation of re-entry horizontal injection well, case study 34 ijcpe vol.13 no.3 (september 2012) -available online at: www.iasj.net 1995. optimising water injection performance. paper spe 29774-ms presented at middle east oil show, 11-14 march 1995, bahrain. 17. uddin s.,., dolan j.d, , chona, r.a., ken, n.h monterio, j.a., alrubaiyea and a.alsharqawi. 2003. lessons learned from the first open whole horizontal well water shutoff job using two new polymer systemsa case history from wafra ratawi field, kuwait. paper spe 81447-ms presented at middle east oil show, 9-12 june 2003, bahrain. 18. jie fang, et. al. 2006. pioneer application and promising future of horizontal water-injection in china. paper spe 104414 –ms presented at international oil and gas conference and exhibition in china, 5-7 december 2006, beijing, china. 19. jreou, g.n. “a study for increasing productivity from r1 formation unit in southern oil field by designing a horizontal wells network”, phd dissertation, baghdad university, october 2007. 20. joshi,s.d. “horizontal well technology”; pennwell publishing company, 1991. 21. special contacts with soc. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.21 no.4 (december 2020) 33 – 40 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: noor sabeeh amory, email: banenahmed1989@gmail.com , name: faleh h.m. almahdawi, email: fhmetr@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. experimental investigation of pomegranate peel and grape seed powder additives on the rheological and filtration properties of un-weighted wbm noor sabeeh amory and faleh h.m. almahdawi university of baghdad, engineering college petroleum department, abstract the chemical additives used to enhance the properties of drilling mud cause damage to humans and the environment. therefore, it is necessary to search for alternative additives to add them to the drilling mud. thus, this study investigates the effects of pomegranate peel and grape seed powders as natural waste when added to un-weighted water-based mud. the test includes measurements of the rheological properties and filtration, as well as the alkanity and density of the drilling mud. the results showed a decrease in ph values with an increase in the concentrations of pomegranate peel or grapeseed, and a decrease in mud density with an increase in powders of pomegranate peel and grape seed concentrations that resulted from the formation of foam. the rheological properties appeared with increasing except for the plastic viscosity. grape seed powders reduce the filter cake thickness required to solve drilling problems caused by an increase in the mud cake thickness. from the laboratory results, it's possible to use powders of pomegranate peel and grape seed as additives to reduce plastic viscosity and filtrate volume. keywords: water-based mud, local material additives, powders of pomegranate peel and grape seed, rheological properties, filtration properties. received on 27/01/2020, accepted on 10/06/2020, published on 30/12/2020 https://doi.org/10.31699/ijcpe.2020.4.4 1introduction drilling muds can be considered complex systems made up of multi phases like solid phase, a liquid phase, and also, contain a chemical phase [1]. the journey of the drilling fluid starts first from the pumping process at the surface to enter the well below the drill string then out of the holes in the bit and through the annular space, it returns to the surface [2]. drilling fluids have a lot of functions such as the cutting's removal from the hole and transport them up to the surface, to transfer hydraulic horsepower to the bit that drills the well, it's used for cooling and lubricating the bit and drill string, to present supporting and protecting for the hole walls, for exerting adequate hydrostatic pressure in the purpose of controlling fluids in the filtrated formations and minimizing of the cuttings settling and weight substance in suspension while circulation is discontinued and for ensure getting maximum information around the penetration of the formations [3]. drilling fluids are broadly classified into pneumatic (gases) or liquid. relying on the continuous phase, drilling fluids of liquid type are divided into water-based mud and oil-based mud [4]. water-based mud is consists of water as the continuous phase, which can be fresh, salt, etc. depended on the additives type utilized to improve its properties, water-based mud is moreover classified into noninhibitive mud, inhibitive mud, and polymer muds [5].drilling fluids rheological properties include plastic & apparent viscosity, yield point, and gel strength, while the filtration properties of drilling muds include both of filtrate volume & filter cake thickness [6]. the high cost of chemicals and their harm to humans and the environment calls for moving to natural materials [7]. when drilling an oil well, different problems associated with drilling fluid properties will appear. as an example, a stuck pipe may be cut or stop the drilling progress for some time (weeks for example) [8]. this period had been named as non-productive time (npt) which is the amount of time spent to free a stuck pipe [9]. the most encouraging to happen stuck pipe is when drilling the wells that need accurate noticing and high technology such as wells with high inclined, drain hole, multilateral, horizontal wells, etc. this problem can ranges in seriousness from small trouble to big complexity, that can have side effects, like drill string loss or in the worst case, a whole loss for the well [10]. different estimates show that stuck pipe costs more than $250 million every year [11]. the drill string sticking is divided into two main types: differential and mechanical sticking. differential sticking happens when the drilling fluid's hydrostatic pressure is higher than the permeable formation's pore pressure. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:banenahmed1989@gmail.com mailto:fhmetr@yahoo.com http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2020.4.4 n. s. amory and f. h.m. almahdawi / iraqi journal of chemical and petroleum engineering 21,4 (2020) 33 40 34 this overbalance compresses the drill string into the wellbore. this happens firstly while the drill string has been stationary or moving unhurriedly and becomes in contact together with a thick mud cake or with a permeable formation [12]. on the other hand, mechanical sticking happens when: insufficient removal of the cutting that drilled exists, instability of the borehole is found, like hole caving, collapse, or sloughing, salt sections squeezing or plastic shale, and key seating [13]. this study focuses on the utilizing of eco-friendly materials (two local materials) to know their influence on the sticking problem. so, the main goals of the present research are to investigate the influence of pomegranate peel powder and grape seed powder with various concentrations on the rheological and filtration properties of un-weighted wbm. 2experimental work 2.1. the materials the materials that were used to prepare un-weighted wbm were given by the baghdad oil training institute. these materials are: a. bentonite the shape of bentonite is illustrated in fig. 1. fig. 1. bentonite b. sodium hydroxide (naoh) fig.2. illustrates the shape of sodium hydroxide. fig. 2. sodium hydroxide c. pomegranate peels powder (ppp) the color of the material is light brown color, similar in its appearance to the dust, relatively lightweight. it blends quickly with drilling muds when it mixes with them but changes the color of the drilling muds to brown or light orange. the shape of ppp before and after grinding is shown below in fig. 3 (a and b). the chemical and structural composition is shown in fig.4. (a) (b) fig. 3. (a. pomegranate peel and b. pomegranate peel powder) fig. 4. structural and chemical composition of pomegranate peels (14). n. s. amory and f. h.m. almahdawi / iraqi journal of chemical and petroleum engineering 21,4 (2020) 33 40 35 d. grape seeds powder (gsp) the chemical composition of gs is includes: water (2840%), oil (10-25%), cellulose (28%), tannin (4-6%), nitrogenous (0, 8-1, 2%), mineral substances (2-4%), acids of fat and other components [15]. grape seeds are found inside the fruit in varying numbers: two, four, more or less, depending on the type of grape. after grinding the seeds, the powder becomes a rough texture like granules with black or dark purple color, which need to mix them well with the drilling fluid. the shape of gsp before and after grinding is shown below in fig. 5 (a and b). (a) (b) fig. 5. (a. grape seeds and b. grape seed powder) table 1. caustic soda specifications [16] chemical name sodium hydroxide chemical formula naoh colour white boiling point ( o c) 1390 melting point ( o c) 318 solubility (water) soluble with the evolution of heat specific gravity 2.13 bulk density (g/ml) 1.175 2.2. equipment the devices used in this research include secondary ones like a blender to mix the solution, electronic balance to weigh the materials, and grinder to grin the local materials. the primary devices include mud balance to measure the drilling muds density, the rotational viscometer to measure the rheological properties, and the api filter press to measure the filtration properties. 2.3. preparation procedure the materials utilized to prepare drilling mud and their concentrations were explained in table 2. the first step in the preparation is to clean the local materials well and dried them for some time, then grind the dried materials more than once to obtain good powder free of big pieces and sieve them also to disposal of large blocks if found, this will facilitate the mixing process with drilling mud. by utilizing electronic balance, the materials have been measured. also, water was measured by measuring cylinders. after the measuring process, water, bentonite, and chemical additives were mixed inside the hamilton beach mixer for 20 minutes. after 22 hours, the local materials were added in different concentrations (0.5, 1, 3, 5, and 7 gm.) and mixed for about 15 minutes. the mixtures were ready for testing different properties (rheology, filtration, density, ph, and gel strength). table 2. compositions of drilling mud samples materials and additives /350ml quantity of additives water(ml) 350 bentonite(gm) 30 naoh(gm) 0.4 pomegranate peel powders(gm) 0.5,1,3,5,7 grape seed powders(gm) 0.5,1,3,5,7 2.4. rheological properties calculation rheological properties contain: 1plastic viscosity (pv) in cp that can be calculated from equation (1) pv=ɵ600-ɵ300 (1) 2yield point (yp) in lb/100ft 2 can be calculated by equation (2) yp=ɵ300-pv (2) 3apparent viscosity (av) in cp which can be calculated by equation (3) av=ɵ600/2 (3) n. s. amory and f. h.m. almahdawi / iraqi journal of chemical and petroleum engineering 21,4 (2020) 33 40 36 3results and discussion 3.1. drilling muds rheological properties un-weighted wbm has been prepared to contain: the basic composition (the known additives) and local material (powders of pomegranate peel & grape seed). to study the nature of these local materials on the behaving of drilling mud, the rheological properties had been measured as shown in table 3 and table 4, fig. 6 to fig. 10. table 3. properties of un-weighted wbm with pomegranate peel powders properties concentrations of ppp(gm.) 0 0.5 1 3 5 7 density(ppg) 8.67 8.3 8.25 8.15 8.1 8 av(cp) 10 15.25 17 24.5 30 33. 5 yp(lb/100𝐟𝟐) 14 11.5 21 35 44 55 pv(cp) 8 9.5 6.5 7 8 6 ph 11.3 11 10.5 10 9 8.5 gel strength (lb/100𝐟𝟐) 10 sec 9.7 3 7.5 26 28 35 table 4. properties of un-weighted wbm with grape seed powders properties concentrations of gsp(gm.) 0.5 1 3 5 7 density(ppg) 8.35 8.25 8.1 8 7.95 av(cp) 15.5 19 22.5 29 29 yp(lb/100𝐟𝟐) 11 20 34 48 50 pv(cp) 10 9 5.5 5 4 ph 11 10 9.5 9 9 gel strength (lb/100𝐟𝟐) 10sec 5.7 10.5 12 12.3 14 fig. 6. plastic viscosities of local materials versus their concentrations of un-weighted wbm fig. 7. apparent viscosity of local materials versus their concentrations of un-weighted wbm fig. 8. yield point of local materials versus their concentrations of un-weighted wbm fig. 9. the alkalinity of local materials versus their concentrations of un-weighted wbm fig. 10. densities of local materials versus their concentrations of un-weighted wbm n. s. amory and f. h.m. almahdawi / iraqi journal of chemical and petroleum engineering 21,4 (2020) 33 40 37 3.2. filtration properties of drilling muds contain various concentrations of local materials: filtration properties in terms of filtrate volume and mud cake thickness had been tested for un-weighted wbm with additives of powders of pomegranate peel and grape seed as shown in table 5. table 5. filtration properties of un-weighted wbm with local material additives properties concentrations of ppp(gm.) 0 0.5 1 3 5 7 v2(ml) 2.5 4.2 3.9 3.5 2.5 2 v4(ml) 4 5.5 5 4.8 4 4 v6(ml) 5.5 6.7 6.02 5.8 4.8 4.9 v7.5(ml) 6 7.2 6.55 6 5.1 5.1 v30(ml) 12 14.4 13.1 12 10.2 10.5 mud cake thickness(mm) 0.65 1 1 1 1 1 properties concentrations of gsp(gm.) 0 0.5 1 3 5 7 v2(ml) 2.5 3.5 3.7 3.7 3.7 3.8 v4(ml) 4 5 4.9 5.5 5.2 5 v6(ml) 5.5 6.2 6.1 6.1 6.1 5.8 v7.5(ml) 6 6.8 7.1 7 6.8 6.4 v30(ml) 12 14.2 14.2 14 13.6 12.8 mud cake thickness(mm) 0.65 1 1 0.55 0.52 0.52 fig. 11. filtrate volume of different concentrations of pomegranate peel powders versus time of un-weighted wbm fig. 12. filtrate volume of different concentrations of grape seed powders versus time of un-weighted wbm fig. 13. filtrate volume of local material additives versus their concentrations of un-weighted wbm fig. 14. the thickness of the mud cake of local material additives at different concentrations of un-weighted wbm after adding the local materials (ppp & gsp) to unweighted wbm, the results as shown in tables and figures above presented that, adding ppp made the plastic viscosity smoothly decreased from a concentration of 0.5 gm. to a concentration of 1 gm. with a rate of (3 cp) and pv increased in (3 & 5 gm.) and return to decrease in (7 gm.) concentration to (6 cp) which was the lowest value among the concentrations. when adding gsp with 3 gm concentration, pv, av, and yp were 5.5 cp, 22.5 cp, and 34 lb/100ft 2 respectively. gsp additives were increased in av and yp and were decreased in pv, density, and ph. the decrease in density yielded from the formation of the foam which occupied volume and made decreasing in the density from 8.34 ppg to 7.95 ppg. also, from the above figures and tables, adding ppp to un-weighted wbm appeared good behavior in terms of filtration properties. for example, when comparing the filtrate volume at 2 minutes with different concentrations, the results appeared improvement in the filtrate loss which is decreases from 4.2 ml at 0.5 gm. to 2 ml at 7 gm. n. s. amory and f. h.m. almahdawi / iraqi journal of chemical and petroleum engineering 21,4 (2020) 33 40 38 also, gsp showed improvement in the filtrate volume but less effective when compared with ppp. the concentration of (7 gm.) was the best among the rest concentrations which gave filtrate volume equal to 12.8 ml. to compare the results with the previous researches [17] experimented with new additives to prevent or decrease differential sticking by using nanoparticles of black carbon with drilling mud to change mud properties. the experiment gave that added black carbon with 30nm initial size of particles has shown improvement in decrease cake thickness, the viscosity decreases and dropped further when the temperature increases, reduced yield point at adding black carbon, and also the reduction rate increases with increasing temperature and black carbon proven its activity to enhance mud properties to decrease pipe sticking. also, (10) investigated the influence of bentonite which is a chemical name called partially hydrolyzed polyacrylamide, lubricant, and carboxymethylcellulose (cmc) on the differential sticking that caused by fluid in the water-based mud. the results show as bentonite clay percentage rise, the torque needed to set free pipe sticking also rise, when cmc was adding to the bentonite clay with the proportion of 5%, the torque needed to set free pipe sticking lowing as well as when cmc portions rise, using 5% of lubricant made the torque required to set free of pipe sticking low and became lower as the adding increase and for obtaining the perfect solution, it should use both cmc and lubricant additives to control the happening of differential pipe sticking. 4conclusions pomegranate peel and grape seed powders showed a decrease in the ph values for all concentrations, which deduce the possibility of using these substances to reduce the high ph of the drilling muds. the use of grape seed powders gives the same impression in changing the rheological properties as in the use of pomegranate peel powders, which resulted in reduced plastic viscosity which reflects the presence of low solid concentration or small internal resistance to flow and an increase in both apparent viscosity and yield point as a result of increasing the attractive forces. the mud density decreased for all samples after adding different concentrations of pomegranate peel and grape seed due to the formation of foam, which indicates the need for anti-foaming materials. with increasing concentrations, grape seed powders have succeeded in reducing the thickness of the mud cake and hence the possibility of using these local materials to decrease pipe sticking problems. abbreviations wbm: water-based mud. ppp: pomegranate peel powder. gsp: grape seed powder. av: apparent viscosity (cp). pv: plastic viscosity (cp). yp: yield point (lb/100ft 2 ). v2: filtrate volume at 2 min, ml, v4: filtrate volume at 4 min, ml. v6: filtrate volume at 6 min, ml. v7.5: filtrate volume at 7.5 min, ml. v30: filtrate volume at 30 min, ml. ɵ600: the dial readings at 600rpm. references [1] faleh h. m. al-mahdawi and karrar saad." enhancement of drilling fluid properties using nanoparticles". iraqi journal of chemical and petroleum engineering, vol.19, issn: 1997-4884, pp.21-26, june 2018. [2] zakaria. m.f. "nanoparticle-based drilling fluids with improved characteristics". m.sc thesis. university of calgary, alberta, 2013. [3] norton. j. iadc drilling manual. houston. international association of drilling contractors, 2000, pp.04-034. [4] elemama. a.e, hussein. r.a.m, ibrahim. a.a.i &mohamed s.a." an improving rheological properties and filter loss of water-base drilling fluids using carboxy methyle cellulose (cmc)". online international interdisciplinary research journal, vol.iv, pp.55-65, may 2014. [5] dhiman. p." experimental investigation of the influence of various nanoparticles on water-based mud, "m.sc thesis. university of alaska fairbanks, 2016. [6] hughes. b. drilling engineering workbook. houston. inteq,1995,pp.20-53 [7] talukdar . p, kalita .s, pandey .a, dutta .u& singh .r." effectiveness of different starches as drilling fluid additives in non damaging drilling fluid". international journal of applied engineering research, vol. 13, pp. 1246912474, number 16, 2018. [8] ryen c, ch henry, and r. gray george. composition and properties of drilling and completion fluids. gulf professional publishing, 2011. [9] n. said amina and a. a.alhaleemb, “analysis of stuck pipe incidents in khabaz field”, ijcpe, vol. 19, no. 4, pp. 47-53, dec. 2018. [10] mahto . v, chaudhary . p.k, and sharma. v.p." study the effect of additives on the differential pipe sticking caused by water based drilling fluid". international conference on oil, gas and petrochemical, pp.71-73, august 2012. http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/162 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/162 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/162 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/162 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/162 https://prism.ucalgary.ca/handle/11023/977 https://prism.ucalgary.ca/handle/11023/977 https://prism.ucalgary.ca/handle/11023/977 https://www.sustech.edu/ https://www.sustech.edu/ https://www.sustech.edu/ https://www.sustech.edu/ https://www.sustech.edu/ https://www.sustech.edu/ https://www.ripublication.com/ijaer18/ijaerv13n16_08.pdf https://www.ripublication.com/ijaer18/ijaerv13n16_08.pdf https://www.ripublication.com/ijaer18/ijaerv13n16_08.pdf https://www.ripublication.com/ijaer18/ijaerv13n16_08.pdf https://www.ripublication.com/ijaer18/ijaerv13n16_08.pdf https://books.google.iq/books?hl=en&lr=&id=ohzanicqpmyc&oi=fnd&pg=pp1&dq=composition+and+properties+of+drilling+and+completion+fluids.+&ots=ecsy3mikax&sig=pxtros2tqjhvp2a-4gixizqmiue&redir_esc=y#v=onepage&q=composition%20and%20properties%20of%20drilling%20and%20completion%20fluids.&f=false https://books.google.iq/books?hl=en&lr=&id=ohzanicqpmyc&oi=fnd&pg=pp1&dq=composition+and+properties+of+drilling+and+completion+fluids.+&ots=ecsy3mikax&sig=pxtros2tqjhvp2a-4gixizqmiue&redir_esc=y#v=onepage&q=composition%20and%20properties%20of%20drilling%20and%20completion%20fluids.&f=false https://books.google.iq/books?hl=en&lr=&id=ohzanicqpmyc&oi=fnd&pg=pp1&dq=composition+and+properties+of+drilling+and+completion+fluids.+&ots=ecsy3mikax&sig=pxtros2tqjhvp2a-4gixizqmiue&redir_esc=y#v=onepage&q=composition%20and%20properties%20of%20drilling%20and%20completion%20fluids.&f=false https://doi.org/10.31699/ijcpe.2018.4.6 https://doi.org/10.31699/ijcpe.2018.4.6 https://doi.org/10.31699/ijcpe.2018.4.6 https://www.semanticscholar.org/paper/study-the-effect-of-additives-on-the-differential-mahto-chaudhary/107710f1135dc6cabe55250b13188c0279efa1a9?p2df https://www.semanticscholar.org/paper/study-the-effect-of-additives-on-the-differential-mahto-chaudhary/107710f1135dc6cabe55250b13188c0279efa1a9?p2df https://www.semanticscholar.org/paper/study-the-effect-of-additives-on-the-differential-mahto-chaudhary/107710f1135dc6cabe55250b13188c0279efa1a9?p2df https://www.semanticscholar.org/paper/study-the-effect-of-additives-on-the-differential-mahto-chaudhary/107710f1135dc6cabe55250b13188c0279efa1a9?p2df https://www.semanticscholar.org/paper/study-the-effect-of-additives-on-the-differential-mahto-chaudhary/107710f1135dc6cabe55250b13188c0279efa1a9?p2df n. s. amory and f. h.m. almahdawi / iraqi journal of chemical and petroleum engineering 21,4 (2020) 33 40 39 [11] shadizadeh . s.r, karimi. f, zoveidavianpoor. m."drilling stuck pipe prediction in iranian oil fields: an artificial neural network approach". iranian journal of chemical engineering, vol. 7, pp.29-41, 2010. [12] fred s. keny and patrick o. oyugi." improving the accuracy of mechanical back off in stuck pipe situation during drilling: case study, mw24, and menengai geothermal project". proceedings of the 7th african rift geothermal conference, 2018, pp.1-9. [13] m. khaghani. "pipe sticking: differential pressure and mechanical pipe sticking". international association of directional drilling, pp.1-4, 2016. [14] spilmont .m, léotoing . l, davicco .m.j, lebecque .p, noirault .e.m, pilet .p, rios .l, wittrant .y and coxam .v." pomegranate peel extract prevents bone loss in a preclinical model of osteoporosis and stimulates osteoblastic differentiation in vitro." nutrients journal. doi:10.3390/nu7115465,pp.92669284,2015. [15] mironeasa.s, leahua .a, codinăa .g.g, stroea .s.g& mironeasa .c." grape seed: physico-chemical, structural characteristics and oil content". journal of agroalimentary processes and technologies.vol.16, pp.1-6, 2010. [16] soda, caustic soda prills (pearl), and caustic soda solid (fused) product specifications, retrieved from, https://causticprills.com/products/specifications/. [17] paiaman. a.m & al-anazi. b.d. "using nanoparticles to decrease differential pipe sticking and its feasibility in iranian oil fields."journal of oil and gas business. [online], pp.1-6, 2008. https://www.researchgate.net/profile/mansoor_zoveidavianpoor/publication/229040683_drilling_stuck_pipe_prediction_in_iranian_oil_fields_an_artificial_neural_network_approach/links/09e4150df1295c62d5000000/drilling-stuck-pipe-prediction-in-iranian-oil-fields-an-artificial-neural-network-approach.pdf https://www.researchgate.net/profile/mansoor_zoveidavianpoor/publication/229040683_drilling_stuck_pipe_prediction_in_iranian_oil_fields_an_artificial_neural_network_approach/links/09e4150df1295c62d5000000/drilling-stuck-pipe-prediction-in-iranian-oil-fields-an-artificial-neural-network-approach.pdf https://www.researchgate.net/profile/mansoor_zoveidavianpoor/publication/229040683_drilling_stuck_pipe_prediction_in_iranian_oil_fields_an_artificial_neural_network_approach/links/09e4150df1295c62d5000000/drilling-stuck-pipe-prediction-in-iranian-oil-fields-an-artificial-neural-network-approach.pdf https://www.researchgate.net/profile/mansoor_zoveidavianpoor/publication/229040683_drilling_stuck_pipe_prediction_in_iranian_oil_fields_an_artificial_neural_network_approach/links/09e4150df1295c62d5000000/drilling-stuck-pipe-prediction-in-iranian-oil-fields-an-artificial-neural-network-approach.pdf https://www.researchgate.net/profile/mansoor_zoveidavianpoor/publication/229040683_drilling_stuck_pipe_prediction_in_iranian_oil_fields_an_artificial_neural_network_approach/links/09e4150df1295c62d5000000/drilling-stuck-pipe-prediction-in-iranian-oil-fields-an-artificial-neural-network-approach.pdf https://www.mdpi.com/2072-6643/7/11/5465 https://www.mdpi.com/2072-6643/7/11/5465 https://www.mdpi.com/2072-6643/7/11/5465 https://www.mdpi.com/2072-6643/7/11/5465 https://www.mdpi.com/2072-6643/7/11/5465 https://www.mdpi.com/2072-6643/7/11/5465 https://www.mdpi.com/2072-6643/7/11/5465 https://www.semanticscholar.org/paper/grape-seed%3a-physico-chemical%2c-structural-and-oil-mironeasa-leahu/d39564a76a87535e547aa513f841772eed3351a3?p2df https://www.semanticscholar.org/paper/grape-seed%3a-physico-chemical%2c-structural-and-oil-mironeasa-leahu/d39564a76a87535e547aa513f841772eed3351a3?p2df https://www.semanticscholar.org/paper/grape-seed%3a-physico-chemical%2c-structural-and-oil-mironeasa-leahu/d39564a76a87535e547aa513f841772eed3351a3?p2df https://www.semanticscholar.org/paper/grape-seed%3a-physico-chemical%2c-structural-and-oil-mironeasa-leahu/d39564a76a87535e547aa513f841772eed3351a3?p2df https://www.semanticscholar.org/paper/grape-seed%3a-physico-chemical%2c-structural-and-oil-mironeasa-leahu/d39564a76a87535e547aa513f841772eed3351a3?p2df https://causticprills.com/products/specifications/ http://ogbus.ru/article/view/using-nanoparticles-to-decrease-differential-pipe-sticking-and-its-feasibility-in-iranian-oil-fields http://ogbus.ru/article/view/using-nanoparticles-to-decrease-differential-pipe-sticking-and-its-feasibility-in-iranian-oil-fields http://ogbus.ru/article/view/using-nanoparticles-to-decrease-differential-pipe-sticking-and-its-feasibility-in-iranian-oil-fields http://ogbus.ru/article/view/using-nanoparticles-to-decrease-differential-pipe-sticking-and-its-feasibility-in-iranian-oil-fields n. s. amory and f. h.m. almahdawi / iraqi journal of chemical and petroleum engineering 21,4 (2020) 33 40 40 الريولوجية الخواص على العنب وبذور الرمان مساحيق قشر الضافات تجريبية دراسة لطين ذو القاعدة المائي غير المثقل والترشيح و نور صبيح اموري المهداوي فالح حسن جامعة بغداد,كلية الهندسة,قسم النفط الخالصة االضافات الكيمائية المستخدمة لتحسين خواص طين الحفر سببت خطر على االنسان والبيئة. لذلك من الضروري البحث عن اضافات بديلة الضافتهم الى طين الحفر. لذلك هذه الدراسة تبحث عن تاثير مساحيق ير المثقل . الفحص قشور الرمان وبذور العنب كمخلفات طبيعية عند اضافتهم الى طين المائي القاعدة غ يتضمن قياسات الخواص الريولوجية والترشيح كذلك فحص القاعدية والكثافة لطين الحفر.النتائج اظهرت نقصان مساحيق قشور في القاعدية مع زيادة التركيز لقشور الرمان اوبذور العنب , ونقصان في الكثافة مع زيادة تراكيز الرغوة. الخواص الريولوجية اظهرت زيادة عدا اللزوجة البالستيكية . وهذا ناتج من تكون الرمان وبذور العنب مسحوق بذور العنب قلل سمك كعكة الطين المطلوبة لحل مشاكل الحفر الناتجة من زيادة سمك كعكة الطين.من ستيكية كاضافات لتقيل اللزوجة البالمساحيق قشور الرمان وبذور العنب النتائج المختبرية , من الممكن استخدام .و حجم الترشيح الكلمات الدالة: طين ذو قاعدة مائية,اضافات مواد محلية, مساحيق من قشور الرمان وبذور العنب,الخواص الريولوجية,خواص الترشيح iraqi journal of chemical and petroleum engineering vol.14 no.4 (december 2013) 5370 issn: 1997-4884 microfiltration membranes for separating oil / water emulsion ahmed faiq al-alawy and samah mohsin al – musawi chemical engineering department – college of engineering – university of baghdad – iraq abstract this research was aimed to study the efficiency of microfiltration membranes for the treatment of oily wastewater and the factors affecting the performance of the microfiltration membranes experimental work were includes operating the microfiltration process using polypropylene membrane (1 micron) and ceramic membrane (0.5 micron) constructed as candle; two methods of operation were examined: dead end and cross flow. the oil emulsion was prepared using two types of oils: vegetable oil and motor oil (classic oil 20w-50). the operating parameters studied are: feed oil concentration 50 – 800 mg/l, feed flow rate 10 – 40 l/h, and temperature 30 – 50 o c, for dead end and cross flow microfiltration. it was found that water flux decreases with increasing operating time and feed oil concentration and increases with increasing operating temperature, feed flow rate and pore size of membrane. also, it was found that rejection percentage of oil increases with increasing flow rate and rejection percentage decreases with increasing time, feed oil concentration, feed temperature and pore size of membrane for dead end and cross flow microfiltration. in cross flow microfiltration, reject concentration (concentrate) increases with increasing flow rate, feed concentration, time and feed temperature. the dead end filter has more flux compared to cross flow filter, while, in cross flow the oil rejection percentage is best than dead end. flux for vegetable oil is more than motor oil but rejection percentage for vegetable oil is less than that for motor oil. the highest recovery ratio was found is 44.8% for cross flow process with recirculation of concentrating stream to feed vessel. the highest rejection percentage of oil was found is 98 % and 97.8 % for cross flow and dead ends respectively. keywords: membrane separation; microfiltration; oil; wastewater; polypropylene membranes; ceramic membrane introduction petroleum refineries and petrochemical plants all generate oily wastewater to some extent, and the oils contained in those wastewaters can vary widely. removal of oils from wastewater is normally one of the first steps in the treatment of wastewater and arguably, the most important treatment step (thomas, 2007). in recent years, considerable attention has been focused on the discharge of oily wastewater and its impact on the environment. pollution of water by oily hydrocarbons is especially harmful to the aquatic life, as it attenuates the light and perturbs the normal mechanism of oxygen transfer (xianguo and gyula, 2005, nandi b.k 2010). iraqi journal of chemical and petroleum engineering university of baghdad college of engineering microfiltration membranes for separating oil / water emulsion 54 ijcpe vol.14 no.4 (december 2013) -available online at: www.iasj.net typical oil concentrations from various industrial sources are: petroleum (10 – 7200 mg/l), metals (100 – 5000 mg/l), food processing (14 – 10550 mg/l), wool (3000 – 20000 mg/l), textiles (20 – 12260 mg/l) and cooling and heating (7 – 1200 mg/l) (syed, 2000). iraqi requirements for the oil in the discharge water are 10 mg/l (jassim, 2008). various types of technologies exist for treatment of oily waters. these methods are gravity separators, dissolved air flotation, coalescers, biological treatment and activated carbon adsorption (shams, et al., 2007). over the past several years, advances have been made in developing an industrial wastewater reclaim system for a separation process for oily industrial wastewater which is extremely effective and economical in recycling of aqueous parts washing solutions. this process is based on a membrane technology that has major technical and commercial advantages over other approaches that have been tried for this application (mike and ivan, 2008). membrane separation technology has been around for many years. initially, the use of membranes was isolated to a laboratory scale. however, improvements over the past twenty years have made it possible to use membranes on an industrial level. a membrane is simply a synthetic barrier, which prevents the transport of certain components based on various characteristics. membranes are very diverse in their nature with the one unifying theme to separate. membranes can be liquid or solid, homogeneous or heterogeneous and can range in thickness. they can be manufactured to be electrically neutral, positive, negative or bipolar. these different characteristics enable membranes to perform many different separations from reverse osmosis to microfiltration. therefore pressure driven membrane processes such as microfiltration (mf), ultrafiltration (uf), nanofiltration (nf) and reverse osmosis (ro) are increasingly being applied for treating oily wastewater (syed, 2000). membranes have several advantages, among them: (cheryan and rajagopalan, 1998)  the technology is more widely applicable across a wide range of industries.  the membrane is a positive barrier to rejected components. thus, the quality of the treated water is more uniform regardless of influent variations. these variations may decrease flux, but generally does not affect quality of its output.  no extraneous chemicals are needed, making subsequent oil recovery easier.  membranes can be used in-process to allow recycling of selected waste streams within a plant.  membrane equipment has a smaller foot print.  the plant can be highly automated and does not require highly skilled operators. microfiltration (mf) is filtration process that operation on a physical sieving separation process. it is best used for the removal of suspended solids, giardia, cryptosporidium and the reduction of turbidity. mf process require low trans membrane pressure (1–30 psi) to operate, and it is also used as a pretreatment to desalination technologies such as reverse osmosis, nanofiltration, and electrodialysis .mf membranes can operate in either cross flow separation or dead-end filtration. cross flow separation is where only part of the feed stream is treated and the remainder of the water is passed through the membrane untreated. in dead-end separation, all of the feed water is treated. the microfiltration membrane can consist of various ahmed faiq al-alawy and samah mohsin al – musawi -available online at: www.iasj.net ijcpe vol.14 no.4 (december 2013) 55 materials like, for example, polysulfone, polypropylene, polyvinyldifluoride (pvdf), polyethersulfone (pes), zro2 and carbon (peter, 2007). in this research study the efficiency of membrane separation process (mf) for oily wastewater treatment, and to achieve low content of oil in permeate and high permeate flux, effects of operating parameters such as oil concentration, temperature, feed flow rate, pore diameters of membranes, time, different types of membranes, different types of oils and methods of different operating (dead end and cross flow) in a microfiltration unit were studied. simple filtration models have also been employed to help analyze the microfiltration membrane – fouling process. membrane fouling models the permeation flux of particle-free water across a clean membrane can be described by darcy’s law as: …(1) where j (m 3 m -2 s -1 ) is the permeation flux, ∆p (pa) the trans membrane pressure (tmp), μ (kg/m.sec) the absolute viscosity of the water, and rm (m -1 ) the hydraulic resistance of the clean membrane (or clean membrane resistance). for suspension filtration, the permeation flux will always be lower than that given by equation (1). flux decline is a result of the increase of membrane resistance to the permeating flow, resulting from membrane fouling or particle deposition on or in the membrane. the mechanisms of membrane fouling usually include pore blocking, concentration polarization and cake formation. for microfiltration, the fouling by concentration polarization may be negligible due to the large size of the particles retained (leow and bai , 2002). thus, the permeation flux through a microfiltration unit treating oily wastewater, can be given, by modifying equation (1), as: (leow and bai, 2002) …(2) where rp (m −1 ) is the resistance due to pore blocking, and rc (m −1 ) the resistance arising from cake formation. for microfiltration at a constant tmp, the initial permeate flux j0; will mainly depend on rm as rp and rc are initially zero. with the proceeding of microfiltration operation, pore blocking and cake formation will cause rp and rc to increase, and change the relative significance of rm, rp, and rc in equation (2), and the microfiltration process can transfer from a membrane resistance to a pore blocking resistance or a cake resistance process. based on this, generally four fouling mechanisms for porous membranes can be observed, these are (subramanian and raghavarao, 2001): a. complete blocking model complete blocking model assumes that particles arrive at the membrane and seal the membrane pores such that the particles are not superimposed upon the other. the blocked surface area is proportional to the permeate volume. b. standard blocking model in standard blocking model, the particle diameter is much less than the pore diameter, thus, the particles can enter most pores, deposit on the pore walls, and thus reduce the pore volume. the decrease of pore volume is also proportional to the permeate volume. microfiltration membranes for separating oil / water emulsion 56 ijcpe vol.14 no.4 (december 2013) -available online at: www.iasj.net c. intermediate blocking model in intermediate blocking model, the number of blocked pores or surface is also assumed to be proportional to the permeate volume but it is less restrictive in such a way that not every particle necessarily blocks the pores and particles may settle on other particles. d. the cake filtration model the cake filtration model is used to explain for the case of large particles, which cannot enter most pores, and hence, deposit forms a cake on the membrane surface. for microfiltration at a constant transmembrane pressure, the permeation fluxes under each of these case may be given as: a. complete pore blocking model: …(3) b. standard pore blocking model: ( ) …(4) c. intermediate pore blocking model: …(5) d. cake filtration model: …(6) where j0 depends on the transmembrane pressure, membrane resistance and viscosity of the filtrate and is expressed as j0 = ∆p/ μrm. the various k terms represent mass transfer coefficients for the associated filtration laws (nandi et al., 2010). in the case of constant pressure filtration, the term (aj0) is constant and the filtration laws can be simplified to: a. complete pore blocking model: …(7) b. standard pore blocking model: ⁄ ⁄ …(8) c. intermediate pore blocking model: ⁄ ⁄ …(9) d. cake filtration model: ⁄ ⁄ …(10) where ks = (1/2) ksa 0.5 , ki = kia, kc = 2kca 2 . consequently plotting the left-hand side flux functions for each model against time are the tests to determine the more appropriate model and the means to obtain the mass transport parameters from the slope. therefore, a plot of ln(j) vs. t, (1/j 0.5 ) vs. t, (1/j) vs. t and (1/j 2 ) vs. t shall be a straight line with slope of kb, ks, ki and kc, with yintercept of ln(j0), )/1( 5.0 0 j , (1/j0) and )/1( 2 0 j for complete pore blocking, standard pore blocking, intermediate pore blocking and cake filtration model, respectively. this is shown in figures 13 to 17. the appropriate fitness and competence of various fouling models can be confirmed by comparing the values of coefficient of correlation (r 2 ) obtained from the linear regression analysis (peng and tremblay, 2008). oil removal efficiency produced water treating equipment performance is commonly described in terms of its “oil removal efficiency.” this efficiency considers only the removal of dispersed oil and neglects the dissolved oil content. for example, if the equipment removes half of the dispersed oil contained in the influent produced water, it is said to have 50% oil removal efficiency. for a specific piece of equipment or an overall ahmed faiq al-alawy and samah mohsin al – musawi -available online at: www.iasj.net ijcpe vol.14 no.4 (december 2013) 57 system, the oil removal efficiency can be calculated using the following equation: ( ) …(11) where r % = oil removal efficiency, (rejection percentage) cp =dispersed oil concentration in the water outlet (effluent) stream, ppm. cf = dispersed oil concentration in the water inlet (influent) stream, ppm. experimental materials these filters have columnar filter element sealed within a pressure vessel to produce dry / wet cake. figure 1 show picture of candle filter. a) ceramic filter: metal filter such as zirconium or titanium oxide over the support structure of an aluminum oxide tube. the specifications of the filter are as follow:  absolute filtration to 0.5 micron  removes algae ,rust ,sediment ,suspended solids  flow rate (liters) to 8 lpm  pressure to 3 bar  turbidity reduction b) polypropylene filter: manufactured from pure 100% polypropylene. the specifications of the filter are as follow :( made in china)  designed for purity and chemical compatibility.  spun fibers from a true gradient density from outer to inner surfaces.  temperature range: 4.4 o c to 62.8 o c  dimensions: l = 25 cm and d = 6.5 cm  effective area: 0.051 m 2  absolute filtration to 1 micron experimental procedure and equipments oil – water emulsions were prepared by vigorous mixing of oil and water in the qvf glass vessel (30 l), using a stirrer (janke and kunkelkg, england, 1 ka – werk, rw 50 h, staufen) at an agitation speed of 0 10000 rpm, classic oil 20w-50 and edible vegetable oil was used for the preparation of the oil-water emulsions with oil concentration of 50, 400 and 800 ppm. the physical and chemical properties of the oil are given in table 1. feed solution was prepared in the qvf glass vessels by mixing with the oil (20w 50) in 30 liter of tap water, since stirring a mixture of small amount of oil in water made an emulsion which was stable during the experiment, no emulsifier was used. the out let valve of the feed vessel was open to let the emulsion fill the whole pipes of the system. the emulsion feed drawn from the feed vessel by means of a centrifugal pump to pass through filter (polypropylene or ceramic) to remove oil from oil – water emulsions. permeate (filtered water) was collected every 30 minutes and volume of permeate during the interval was measured and recorded. the oil concentrations in the feed and permeate solutions were analyzed using uv spectrophotometer. the filtration flux was calculated by dividing the permeate volume by the product of effective membrane area and time. an experimental rig was constructed in the laboratory as shown schematically in figure 2 and pictured in figure 3. experimental system consists of: 1) microfiltration membrane: two types of filters candlepolypropylene (1 micron) and candle-ceramic (0.5 micron) are used to remove oil from wastewater. microfiltration membranes for separating oil / water emulsion 58 ijcpe vol.14 no.4 (december 2013) -available online at: www.iasj.net 2) feed vessel: the qvf glass vessels with a capacity of 30 liters were used as feed vessel. 3) rotameters: calibrated rotameters is used to measure the volumetric flow rate of feed (o/w emulsions) inlet to membrane separation unit (range of 10 – 60 l/h). 4) pressure gauge: one pressure gauge is used in the feed (o/w emulsions) line to indicate the feed pressure (range of 0 – 2.5 bar). 5) heater: in order to maintain the temperature at a certain value, one submersible electrical coil (220 volt, 1000 watt) and thermostat of range from 0 to 80 o c was used as a heating media. 6) ph meter: the ph value measurement was carried out by means of a bench ph meter with specification as following: (type = sensodirect ph200 , range = 0 – 14 ph, accuracy = ± 0.01 ph, power requirements = ac/dc 6v ) 7) digital balance: a digital balance with 4 decimal points (sartorius bp3015 max. 303 g, d = 0.1 mg) is used to measure the samples weight in experiments. 8) pump: centrifugal pump was used to pump the feed (o/w emulsions) from vessel to membrane cell (54.5 – 11.4 l/min, 3 – 13.7 m. h, 210 watt, stuart turner ltd. henley on thames eng. (england)). 9) spectrophotometer: the concentration of oil in water was measured using spectrophotometer, with specification as following: ( model = genesys 10 uv, wave length = 1090 – 190 nm ,power = 50 / 60 hz made in u.s.a) results and discussion in oily waste water treatment processes, oil concentration in emulsion often changes because of different input situations. effect of oil concentration in this process, higher concentration from the feed oil is produced the lower permeate flux. this is shown in figure 4. the feed oil concentration has a direct influence on adsorption of oil (fouling). fouling is mainly due to adsorption of oil on the membrane structure, which modifies the critical surface tension and the wettability, as well as the effective pore diameter, resulting in reduced membrane permeability (sama, 2011; rajagopalan, 1998). the high oil concentration in feed increases the oil adsorption and causes easily great resistance for permeating water. therefore, figure 5 illustrates the permeate (or product) concentration of oil increased with the increase in feed concentration. the increase of oil concentration will decrease the rejection percentage and vice versa (according to equation 11). as the feed concentration of oil increases, the reject concentration (or concentrate) will increase. this is shown in figure 6. also, we can by increasing the operation time, the flux, oil rejection, and reject concentration will decreases. a similar observation was noticed in the experimental study of (lawrence and jiaping, 2011). the pressure and ph value for all experiments are 0.125 bar and 8.2 respectively. effect of operating temperature in figure 7, the permeate flux increased with an increase in the temperature. the higher temperature may lead to an enhancement of the activity of water molecules and a decline of the emulsion viscosity. therefore, the rejection percentage of oil decreased with increase in operating temperature i.e. the oil concentration in product increased. ahmed faiq al-alawy and samah mohsin al – musawi -available online at: www.iasj.net ijcpe vol.14 no.4 (december 2013) 59 this is shown in figure 8. the effect of temperature on the flux and permeate concentration explains the effect of temperature on reject concentration. thus, the reject concentration increases with increasing temperature (see figure 9). these results correspond with the results of the researcher (sama, 2011; lawrence, 2011). effect of flow rate flow rate is an important operation parameter for mf. high flow rate is used to reduce cake formation and/or concentration polarization. the convection to and diffusion away from the membrane surface determine the rate of build-up of fouling, the rate of convection to the membrane is a function of the permeate flux, and the diffusion away is linked to the degree of turbulence (cheryan and rajagopalan, 1998). according to this information we observe, the flux increased with an increase in feed flow rate. an increase in the cross-flow velocity will directly increase in oil rejection % and increase in the reject concentration. this is shown in figures 10 to 12. these results correspond with the results of the researcher (samah, 2013). the filtration models figures 13 to 17 show application of hermia's model (filtration models) for prediction and experimental data in dead end process. in most cases the models exhibit a reasonable agreement with experimental data giving linear correlations. the model correlations for each case are given in figures 13 to 17. the estimation of the flux at t = 0 (j0), from the intercept, gives the following values, 187.73, 189.94, 192.68 and 200.32 l/m 2 .h for the complete pore blocking, standard pore blocking, intermediate pore blocking and cake filtration models, respectively. these values are different from the initial experimental flux, measure at 196.07 l/m 2 .h. the best agreement with experimental data is given by the complete pore blocking model and came in second level, the standard model for polypropylene membrane (1 μm). these results correspond with the results of the researcher (hasan, 2011; erik, 1989). conclusions the following conclusions could be drawn from this study: 1. microfiltration can be used for the treatment of oily wastewater. 2. the flux decreases with increasing operating time and feed oil concentration. while, the flux of the membrane increases with increasing operating temperature, feed flow rate and pore size of membrane for dead end and cross flow. 3. the oil rejection percent increases with increasing flow rate. while, the rejection percentage decreases with increasing time, feed oil concentration, feed temperature and pore size of membrane for dead end and cross flow. 4. the reject concentration (or the concentrate) increases with increasing flow rate, feed concentration, time and feed temperature. 5. in the dead end process the amount of flux is more than cross flow process. while, in the cross flow the oil rejection percentage is best than dead end. 6. the amount of flux for vegetable oil more than oil 20w-50, but rejection percentage for vegetable oil is less than rejection percentage for oil 20w-50. 7. the highest recovery ratio is 44.8% using cross flow process with recirculation of concentrate stream. 8. in the microfiltration process, the highest rejection percentage of oil is microfiltration membranes for separating oil / water emulsion 60 ijcpe vol.14 no.4 (december 2013) -available online at: www.iasj.net 98% and 97.8% for cross flow and dead end respectively. experimental results in this work were in excellent agreement with complete pore blocking model and the standard model. nomenclature units description symbol pa transmembrane pressure p kg/m.sec viscosity µ m 2 area a mg/l feed concentration cf mg/l permeate concentration cp kg .m/s 2 centrifugal force f m 3 /m 2 .sec permeation flux j m 3 /m 2 .sec initial permeate flux j0 m/sec mass transfer coefficient for complete pore blocking model kb m/sec mass transfer coefficient for cake filtration model kc m/sec mass transfer coefficient for intermediate pore blocking model ki m/sec mass transfer coefficient for standard pore blocking model ks kg mass of particle m l/hr feed flow rate qfeed l/hr permeate (or product) flow rate qpermeate m distance from central axis rotation r rejection percentage r % correlation of coefficient r 2 m -1 cake resistance rc m -1 clean membrane resistance rm m -1 pore blocking resistance rp h time t o c temperature t rad/s angular velocity ω abbreviation description symbol microfiltration mf oil-in-water o/w water-in-oil w/o references 1beccari m., majone m., riccardi c., savarese f. and torrisi l. (1999). “integrated treatment of olive oil mill effluents: effect of chemical and physical pretreatment on anaerobic treatment”, water sci. tech., 40(1), 347-355. 2cheryan m. (1998) “ultrafiltration and microfiltration handbook”, pp. ahmed faiq al-alawy and samah mohsin al – musawi -available online at: www.iasj.net ijcpe vol.14 no.4 (december 2013) 61 71-112. lancaster, united states: technomic publishing company. 3cheryan m. and rajagopalan n. (1998): “membrane processing of oily streams”, wastewater treatment and waste reduction, j. membr. sci., 151(1), 13-28. 4h.f. leow and r.b. bai (2002) “modeling and experimental study of microfiltration using a composite module”, j. membr. sci. 204 359. 5hasan ferhood makki, ahmed faiq al-alawy, maha h. al-hassani and zaid waadulla rashad (april 2011) “membranes separation process for oily wastewater treatment” , journal of engineering, number2 volume 17.p 15 6jassim m.k., (2008), "using of local bentonite for removal of oil contaminants from industrial wastewater", m.sc. thesis, university of baghdad. 7lawrence k. wang and jiaping p. chen (2011), ” membrane and desalination technologies” handbook of environmental engineering, vol. 13,p 178 8mike p. and ivan a.c., (2008), "ultrafiltration for oily industrial water", nc awwa-wea conference november 17. 9nandi b.k., moparthi a., uppaluri r. and purkait m.k. (2010), "treatment of oily wastewater using low cost ceramic membrane: comparative assessment of pore blocking and artificial neural network models", chemical engineering research and design. 10peng h. and tremblay a.y. (2008), "membrane regeneration and filtration modeling in treating oily wastewaters", journal of membrane science (324), 59 – 66. 11peter a. williams (2007) “handbook of industrial water soluble polymers” by blackwell publishing ltd. 12sama mohammed abdullah (april 2011) “oily water treatment using ceramic memberane” , journal of engineering, number2 volume 17,p25 13 samah mohsin al – musawi, (2013), "separation of oil from oil in water emulsions using ", m.sc. microfiltration membranes thesis, university of baghdad. 14schramm l. l. (1992), “petroleum emulsions-basic principles”, in emulsions: fundamentals and applications in the petroleum industry, american chemical society, washington, d.c., pp. 1–49. 15shams ashaghi, k., ebrahimi, m. and czermak, p., (2007), "ceramic ultraand nanofiltration membranes for oilfield produced water treatment: a mini review", the open environmental journal, (1), 1-8. 16shaw d. j. (1991) “introduction to colloid and surface chemistry” fourth edition, butterworth heinemann ltd, great britain. 17syed r.q., edward m.m. and guang z., (2000), "water works engineering: planning, design, and operation", prentice – hall, inc., usa. 18thomas e. schultz (2007), “wastewater treatment for the petroleum industry”, technology and trends specialist article, panda select oil and gas. 19xianguo hu and gyula vatai (2005), “ultrafiltration of oily emulsion for metal cutting fluid: role of feed temperature” , environment protection engineering , vol. 31,no. 3-4. microfiltration membranes for separating oil / water emulsion 62 ijcpe vol.14 no.4 (december 2013) -available online at: www.iasj.net table 1, the physical and chemical properties of oil classic oil 20w-50 viscosity grade 20w-50 colour amber physical state liquid at ambient temperature odour characteristic mineral oil vapour pressure expected to be less than 0.5 pa at 20 °c initial boiling point expected to be above 280 °c solubility in water negligible density 888 kg/m 3 at 15 ºc. flash point 215 ºc flammable limits upper 1% (v/v) flammable limits lower 10% (v/v) auto-ignition temperature expected to be above 320ºc kinematic viscosity 157 mm 2 /s at 40 ºc pour point -27 ºc vegetable oil density 985 kg/m 3 viscosity 4.01×10 -2 kg/m.sec type zer (made in turkey) fig. 1, candle filter fig. 2, schematic diagram of microfiltration process ahmed faiq al-alawy and samah mohsin al – musawi -available online at: www.iasj.net ijcpe vol.14 no.4 (december 2013) 63 fig. 3, picture experimental system consists fig. 4, flux vs. time at different oil concentrations (ceramic 0.5 µm, qf = 25 l/h, oil 20w50 and t = 40°c) 150 200 250 300 350 400 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 f lu x , l/ m 2 h time, h cғ = 50 ppm cғ = 400 ppm cғ = 800 ppm microfiltration membranes for separating oil / water emulsion 64 ijcpe vol.14 no.4 (december 2013) -available online at: www.iasj.net fig. 5, oil rejection % vs. time at different oil concentrations (ceramic 0.5 µm, qf = 25 l/h, oil 20w-50 and t = 40°c) fig. 6, reject concentration vs. time at different oil concentration (ceramic 0.5 µm, qf = 25 l/h, oil 20w-50 and t = 40°c) 50 55 60 65 70 75 80 85 90 95 100 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 o il r e je c ti o n % time, h cf = 50 ppm cf = 400 ppm cf = 800 ppm 0 200 400 600 800 1000 1200 1400 1600 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 r e je c t c o n c e n tr a ti o n , p p m time, h cf = 50 ppm cf = 400 ppm cf = 800 ppm ahmed faiq al-alawy and samah mohsin al – musawi -available online at: www.iasj.net ijcpe vol.14 no.4 (december 2013) 65 fig. 7, flux vs. time at different feed temperature (ceramic 0.5 µm, qf = 25 l/h, oil 20w-50 and cf = 400 ppm) fig. 8, oil rejection % vs. time at different feed temperature (ceramic 0.5 µm, qf = 25 l/h, oil 20w-50 and cf = 400 ppm) 150 200 250 300 350 400 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 f lu x , l/ m 2 h time, h t = 30 ᴼc t = 40 ᴼc t = 50 ᴼc 60 70 80 90 100 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 o il r e je c ti o n % time, h t = 30 ᴼc t = 40 ᴼc t = 50 ᴼc microfiltration membranes for separating oil / water emulsion 66 ijcpe vol.14 no.4 (december 2013) -available online at: www.iasj.net fig. 9, reject concentrations vs. time at different feed temp. (ceramic 0.5 µm, qf = 25 l/h, oil 20w-50 and cf = 400 ppm) fig. 10, flux vs. time at different feed flow rate (ceramic 0.5 µm, t = 40°c, oil 20w-50 and cf = 400 ppm) 500 550 600 650 700 750 800 850 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 r e je c t c o n c e n tr a ti o n , p p m time, h t = 30 ᴼc t = 40 ᴼc t = 50 ᴼc 0 100 200 300 400 500 600 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 f lu x , l/ m 2 h time, h qf = 15 l/h qf = 25 l/h qf = 40 l/h ahmed faiq al-alawy and samah mohsin al – musawi -available online at: www.iasj.net ijcpe vol.14 no.4 (december 2013) 67 fig. 11, oil rejection % vs. time at different feed flow rate (ceramic 0.5 µm, t = 40°c, oil 20w50 and cf = 400 ppm) fig. 12, reject concentration vs. time at different feed flow rate (ceramic 0.5 µm, cf = 400 ppm, oil 20w-50 and t = 40°c) 60 65 70 75 80 85 90 95 100 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 o il r e je c ti o n % time, h qf = 15 l/h qf = 25 l/h qf = 40 l/h 500 550 600 650 700 750 800 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 r e je c t c o n c e n tr a ti o n , p p m time, h qf = 15 l/h qf = 25 l/h qf = 40 l/h microfiltration membranes for separating oil / water emulsion 68 ijcpe vol.14 no.4 (december 2013) -available online at: www.iasj.net fig. 13, complete pore blocking model (cf = 400 ppm, t = 30°c and qf = 10 l/h) fig. 14, standard pore blocking model (cf = 400 ppm, t = 30°c and qf = 10 l/h) ln(j) = -0.13(t) + 5.235 r² = 0.9864 4.80 4.85 4.90 4.95 5.00 5.05 5.10 5.15 5.20 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 ln (j , l/ m ²h ) time,h (1/j0.5 ) = 0.534(t) + 7.2562 r² = 0.9826 7.4 7.8 8.2 8.6 9.0 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 j ¯ 0 .5 * 1 0 0 time,h ahmed faiq al-alawy and samah mohsin al – musawi -available online at: www.iasj.net ijcpe vol.14 no.4 (december 2013) 69 fig. 15, intermediate pore blocking model (cf = 400 ppm, t = 30°c and qf = 10 l/h) fig. 16, cake filtration model (cf = 400 ppm, t = 30°c and qf = 10 l/h) (1/j) = 0.8789(t) + 5.1917 r² = 0.9778 5.5 6.0 6.5 7.0 7.5 8.0 8.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 (1 /j ) * 1 0 0 0 time , h (1/j2) = 1.197(t) + 2.4919 r² = 0.9653 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 j 2 * 1 0 5 time , h microfiltration membranes for separating oil / water emulsion 70 ijcpe vol.14 no.4 (december 2013) -available online at: www.iasj.net fig. 17, comparison of filtration model prediction with experimental data for polypropylene membrane (1 µm) 120 130 140 150 160 170 180 190 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 f lu x , l/ m 2 h time , h experimental data complete blocking standar d blocking intermediate blocking cake filtrat ion iraqi journal of chemical and petroleum engineering vol.13 no.2 (june 2012) 1127 issn: 1997-4884 prediction and correlations of residual entropy of superheated vapor for pure compounds mahmoud o. abdullah, sarmad t. najim and shahad z. atta chemical engineering department, college of engineering, university of nahrain abstract prediction of accurate values of residual entropy (s r ) is necessary step for the calculation of the entropy. in this paper, different equations of state were tested for the available 2791 experimental data points of 20 pure superheated vapor compounds (14 pure nonpolar compounds + 6 pure polar compounds). the average absolute deviation (aad) for s r of 2791 experimental data points of the all 20 pure compounds (nonpolar and polar) when using equations of lee-kesler, pengrobinson, virial truncated to second and to third terms, and soave-redlich-kwong were 4.0591, 4.5849, 4.9686, 5.0350, and 4.3084 j/mol.k respectively. it was found from these results that the lee-kesler equation was the best (more accurate) one compared with the others, but this equation is sometimes not very preferable. it was noted that srk equation was the closest one in its accuracy to that of the lee-kesler equation in calculating the residual entropy s r of superheated vapor, but it was developed primarily for calculating vapor-liquid equilibrium and to overcome this problem, efforts were directed toward the possibility of modifying srk equation to increase its accuracy in predicting the residual entropy as much as possible. the modification was made by redefining the parameter α in srk equation to be a function of reduced pressure, acentric factor, and polarity factor for polar compounds in addition to be originally function of reduced temperature and n parameter –which is also function of acentric factor– by using statistical methods. this correlation is as follows:   21  n ,  4996932.0434091.0 370002.0064049.0920338.0   trptp rrr this new modified correlation decreases the deviations in the results obtained by using srk equation in calculating s r when comparing with the experimental data. the aad for 2791 experimental data points of 20 pure compounds is 4.3084 j/mol.k while it becomes 2.4621 j/mol.k after modification. thus srk equation after this modification gives more accurate results for residual entropy of superheated vapor of pure 20 compounds than the rest of the equations mentioned above. keywords: entropy, residual entropy, superheated vapor, equation of state, reduced temperature, reduced pressure, acentric factor, and polarity factor. introduction thermodynamics has been called by many “the science of energy and entropy”. however, unlike energy, the word entropy is seldom heard in everyday conversation; energy and iraqi journal of chemical and petroleum engineering university of baghdad college of engineering prediction and correlations of residual entropy of superheated vapor for pure compounds 12 ijcpe vol.13 no.2 (june 2012) -available online at: www.iasj.net entropy play important roles in thermal systems engineering [1]. although there are many ways to introduce the concept of entropy, the simplest is just to deal with its utility; namely: a mathematical tool to describe the direction in which things actually occur and if it occurs spontaneously or not. it is one of the thermodynamic properties of fluids that are essential for the design process equipments that calculate the heat and work requirements of industrial process. also the analysis of the performance of compressors or expanders requires knowledge of the entropy behavior. neither energy nor entropy can be measured directly on energy or entropy meter, so values are usually expressed in relation to an arbitrary reference state depending on the experimental data of another property that can be measured experimentally such as temperature and pressure denoted by t and p, respectively [2, 3]. one of the important ways to obtain the entropy data for pure substances at various states is the experimental data usually available in graphical or tabular forms, but for graphical it is a more complicated method in practical use compared with the property tables that when simply provide very accurate information about the properties, but they are very bulky and vulnerable to typographical errors [2] and many times some interpolations between two pressures or temperatures are needed to obtain the value of a thermodynamic property of entropy at certain points. also for the phase of superheated vapor, it is so difficult reaching the conditions of high pressures or temperatures for many compounds in laboratory. thus a more practical and desirable approach is based on equation of state (eos). pure gases are categorized into [4]: 1. nonpolar gases which include: a. simple fluids with spherical molecules ω=0 such as argon, krypton, b. quantum gases having ω<0 such as he, h2, and c. other nonpolar fluids which have ω>0 such as benzene, propane. 2. polar gases that can be subdivided into: a. non-hydrogen bonding compounds such as ketones, and aldehydes, and b. hydrogen bonding compounds (a bond forms between the h atom attached to oxygen atom in one molecule with the oxygen atom of another molecule) such as alcohols, and water. in addition to acentricity, the polar compounds are characterized by the presence of dipole moment arises from positive and negative charges that are present in the molecule. there is no precise recommended method for calculating entropy or residual entropy for superheated vapor. this work involves studying the deviation in calculated entropy values from its actual values (obtained by available experimental data for different compounds: polar and nonpolar gases) and then stating which method is more suitable than the others. eos (models) the most convenient method of representing the properties or the behavior of a substance, is by a mathematical expression; that is, an equation which represent the (p-v-t) behavior of a fluid. a general form of such an expression known as eos is:   0,, tvpf …(1) 1. soave-redlich-kwong (srk) equation soave [5, 6] in 1972 introduced a modification on the redlich-kwong (rk) equation of state ; this modification has been successful in mahmoud o. a bdullah, sarmad t. najim and shahad z. atta -available online at: www.iasj.net ijcpe vol.13 no.2 (june 2012) 13 extending the applicability of rk equation to be applied with high accuracy for wide range of non-polar and slightly polar components. the temperature dependent term a/t 0.5 of the rk equation was altered to include both the temperature and the acentric factor by soave; the srk equation is [7]:  bvv a bv rt p      …(2) where the factor α is an empirical function determined from the vaporpressure data of pure hydrocarbons. the srk equation for residual entropy is:          z b aa bd bz r s r 1lnln  …(3) the cubic form in terms of compressibility factor is:     0abzbbazb1z 223  ...(4) where 2 42747.0 r r t p a  , r r t p b 08664.0 …(5) c c p tr a 22 42747.0 , c c p rt b 08664.0 ...(6)   25.011 r tn  …(7a) 2 1561.055171.148508.0  n …(7b) and r tnad  …(8) 2. peng-robinson (pr) equation the equation of peng and robinson in 1976 [8] is rather structurally similar to the srk and, like the srk, requires only the critical constants and the acentric factor for its application for a pure fluid. this equation of state was developed primarily for vapor liquid equilibrium predictions. peng-robinson modified the standard form as follows [7]:    bvbbvv a bv rt p      ...(9) the srk equation for residual entropy is:            bz bz aa bd bz r s r 414.0 414.2 ln 828.2 ln  …(10) the cubic form in terms of compressibility factor is:       0231 32223  bbabzbbazbz …(11) where 2 45724.0 r r t p a  , r r t p b 07780.0 …(12) c c p tr a 22 45724.0 , c c p rt b 07780.0   25.011 r tn  ...(13) 2 26992.05422.137464.0  n ...(14) also, r tnad  …(15) 3. lee-kesler equation lee and kesler in (1975) [9] developed an analytical correlation, based on pitzer’s three-parameter corresponding states principle [10] to provide increased accuracy and covering the whole range of tr and pr of practical interest in hydrocarbon processing. it is to be noted that the original correlations by pitzer et al. were limited to reduced temperatures above 0.8. pitzer et al. correlations for the compressibility factor of a fluid whose acentric factor is ω are given by the following equation: prediction and correlations of residual entropy of superheated vapor for pure compounds 14 ijcpe vol.13 no.2 (june 2012) -available online at: www.iasj.net    10 zzz  …(16) where z (0) is the compressibility factor of a simple fluid and z (1) corrects z (0) for the effects of nonspherical intermolecular forces (primarily dispersion and overlap). z (0) and z (1) are assumed functions of tr and pr. however, lee and kesler found that the compressibility factor of any fluid is a function of the compressibility of a simple fluid (z (0) ), the compressibility of a reference fluid (z (r) ), and the acentric factor, where z (0) and z (r) are functions of tr and pr and the correlation of lee and kesler takes the form:       00 zzzz r r    …(17) where ω r =0.3978 and it is the acentric factor for reference fluid, and the correction term z (1) in eq. (16) is obviously equivalent to (z (r) z (0) ) ∕ ω r this expression is convenient since both z (r) and z (0) are given by the same equation with, however, different constants. lee and kesler chose noctane as the heavy reference fluid since it is the heaviest hydrocarbon for which there are accurate (p-v-t) and enthalpy data over a wide range of conditions [9, 11]. the function for both the simple fluid z (0) and the reference fluid z (r) are derived through a combination of experimental data and a reduced form of the modified benedict-webb-rubin [9, 11] equation of state with a different set of constants that are scheduled in table (1).                           2223 4 52 exp1 rrrrrrrr rr vvvt c v d v c v b t vp z   …(18) 3 4 2 32 1 rrr t b t b t b bb  …(19) 3 r 3 r 2 1 t c t c cc  …(20) r 2 1 t d dd  …(21) table 1, constants for calculating equation (18) [9] for calculating z for the fluid of interest given at t and p, first the appropriate values of tr (t/tc) and pr (p/pc) are calculated by using critical properties of the fluid. from the simple fluid constants in table (1), eq. (18) solves vr –which is not the correct reduced volume for the fluid of interest, but rather a pseudo–reduced volume– by the trial and error method when vr is defined as (pcv/rtc), which can be considered the initial guess for the calculation, or from the first equality of eq. (18) the initial guess can be taken as: r r r p t zv  …(22) the previous equation was depended by paul and francis [12] in preparing their computer program for the tables of constants simple fluid (0) reference fluid (r) b1 b2 b3 b4 c1 c2 c3 c4 d1×10 4 d2×10 4 β γ 0.1181193 0.265729 0.15479 0.030323 0.0236744 0.0186984 0.0 0.042724 0.155488 0.623689 0.65392 0.060167 0.2026579 0.331511 0.027655 0.203488 0.0313385 0.0503618 0.016901 0.041577 0.48736 0.0740336 1.226 0.03754 mahmoud o. a bdullah, sarmad t. najim and shahad z. atta -available online at: www.iasj.net ijcpe vol.13 no.2 (june 2012) 15 lee and kesler  . after trial and error calculation the obtained value of vr = vr (0) for simple fluid and when employed in the first equality of eq. (18), z (0) is calculated for simple fluid. this process is then repeated using the reference fluid constants with the same tr and pr values of the fluid of interest to find vr = vr (r) and z (r) for the reference fluid. finally, with z (0) from the first calculation and z (r) from the second, the compressibility factor z for the fluid of interest is determined from eq. (17) [9]. the residual entropy is derived from eq. (18):   r rr ig v t b t b b z p p r ss                      3 4 2 3 1 * 2 lnln e v d v t c c rr r 2 52 2 5 1 2 3 3 1          …(23)  paul and francis [12] took the initial guess for z of eq. (23) equal to 0.2 but in this research which concentrates on the vapor phases especially superheated vapor the initial z value taken equal to 1 because for vapor phases at high reduced temperatures and pressures the z value often more than unity [13]. where:                           223 4 exp11 2 rrr vvt c e    ...(24) after determining vr (0) and z (0) for the simple fluid at the tr and pr appropriate for the fluid of interest, and employing eq. (23) with the simple fluid constants in table (1), (s-s ig )/r is calculated. this term represents [(s-s ig )/r] (0) in this calculation and z in eq. (23) is z (0) . then, when repeating the same calculation, using the same tr and p r and the values of vr (r) and z (r) for the reference fluid also determined previously, but employing the reference fluid constants from table (1), eq. (23) allows the calculation of [(s-s ig )/r] (r) . now, determining the residual entropy function for the fluid of interest from:      0 ** lnln                             p p r ss p p r ss igig                                                    0 ** lnln p p r ss p p r ss ig r ig r   …(25) 4. virial equation the virial equation of state, also called the virial expansion, is the most interesting and versatile of the equations of state which are used to describe the (p-v-t) properties of a fluid and its importance is due to that it has a sound theoretical basis. it is a polynomial series in pressure or in inverse volume whose coefficients are functions only of t for a pure fluid. virial coefficients are classified into many truncated forms according to the order of the term series. the consistent forms for the initial terms are:       32 1 v td v tc v tb rt pv z  …(26a) 32 1  dcb  …(26b)  pdpcpb1 …(26c) the coefficient b or b' is called the second virial coefficient; c or c' is called the third virial coefficient, and so on. in practice, since not all of the coefficients of the virial series are known, and only data of the second virial coefficients are plentiful in the literature, terms above the third virial coefficient are rarely used in chemical thermodynamics and the series is usually limited in practice up to moderate pressures. however, the advantages of the virial equation could be increased if quantitative information prediction and correlations of residual entropy of superheated vapor for pure compounds 16 ijcpe vol.13 no.2 (june 2012) -available online at: www.iasj.net were available on the third virial coefficient [3, 14, 15]. 4.1. relations between the virial coefficients the virial expansion for p is:               32 1 v td v tc v tb v rt p ...(27) the coefficients of the expansion in pressure are related to the coefficients of the expansion in density (1/v) as follows [16]: rt b bbrtb  ...(28a)      22 bcrtc    2 2 rt bc c   ...(28b) the first step of the derivation of these relations is by solving the original virial expansion for p above and then by equating the two virial expansions, and finally by substituting this expression for p into the pressure form-side of resulting equation to obtain: 22 11 1 11 1 v rtbb v rtb v c v b      2 2 1 v rtc ...(29) both sides of equation (29) are power series in 1/v (third and higher powers of 1/v were omitted because the second power is the highest power used by the common references). since the two power series must be equal, the coefficients of each power of 1/v must be the same on both sides. this comparison provides the relations between the coefficients [15]. 4.2. second virial coefficient correlation of second virial coefficient of both polar and nonpolar systems is presented by [4, 15]. rt bp pb v b z  111 … (30) tsonopoulos correlation for b is:     10 bb p rt b c c  ...(31)   832 0 000607.00121.01385.033.0 1445.0 rrrr tttt b  …(32)   832 1 008.0423.0331.0 0637.0 rrr ttt b  …(33) 4.3. third virial coefficient at high pressures -above 1500 kpa equations (26a, b, and c) may be truncated after three terms [13]: 2 2 11 pcpb v c v b z  …(34) orbey-vera correlation for c is:     10 2 cc p rt c c c          ...(35)   5.108.2 0 00313.002432.0 01407.0 rr tt c  ...(36)   5.10638.2 1 00228.0003.004.00177.0 02676.0 rrrr tttt c  …(37) by using the residual properties, the final expression of the residual entropy after derivation can be expressed as [13]:                                    2 2 2 2 1 rt p dt db btb dt dc tc r p dt db r ss ig …(38) mahmoud o. a bdullah, sarmad t. najim and shahad z. atta -available online at: www.iasj.net ijcpe vol.13 no.2 (june 2012) 17 the aim of the present work is to calculate the residual entropy by ‎using lee-kesler, peng-robinson, virial truncated to b or to c terms, and ‎soave-redlich-kwong equations to determine the deviation from the ‎actual residual entropy using statistical methods to modify the best equation ‎depending on the shape of particle (ω) in addition to the polarity factor (χ) for ‎the polar gases in order to come out with an equation that predicts the residual ‎entropy for different types of superheated vapor of pure gases with high ‎agreement with experimental data.‎ acentric factor in 1955, pitzer [10] observed that the reduced vapor pressures of molecules with acentric force fields are lower than that of simple fluids, and the difference is greater for the molecules of greater acentricity. pitzer noted that all vapor pressure data for the simple fluids (ar, kr, and xe) lie on the same line when plotted as log10 pr sat vs. 1/tr and that the line passes through log10 pr sat = -1.0 at tr = 0.7. this is illustrated in fig. (1). data for other fluids define other lines whose location can be fixed in relation to the line of simple fluids. thereupon, pitzer defined the acentric factor ω (a third parameter) of a substance by [15]:   7.0 10 log1   rt s r p ...(39) therefore ω can be determined for any fluid from tc, pc, and a single vaporpressure measurement was made at tr = 0.7 which is near the normal boiling point of most substances, so the importance of choosing tr = 0.7 that was adopted by pitzer not only provides numerical simplicity (log10pr sat = -1 for simple fluids) but also is beneficial because vapor pressure data are most commonly available at near atmospheric pressure [15]. fig.1, approximate temperature dependence of the reduced vapor pressure [15] polarity factor of halm and stiel because the vapor pressure formed the basis for the definition of the acentric factor, this property was chosen as the starting point for the extension of the normal fluid approach to polar fluids to obtaining polarity factor χ which is an empirical parameter for polar substances similar to the acentric factor for normal fluids. the factor χ is defined to be zero for normal fluids and can be expressed for polar fluids as follows:  7.1552.1log 6.0  rt r s p …(40) values of χ can be obtained from the literatures for some polar compounds[17, 18]. calculation of entropy for superheated region the calculation of entropy for superheated region needing four steps in a calculational path leading from an initial to a final state of a system as obtained in equation below:   2 1 12 1 2 ln t t rrig pv ss p p r t dt css …(41) thus, in fig. (2) the actual path from state 1 to state 2 – the dashed line – is replaced by a four-step calculational path; these steps visualize the sum of prediction and correlations of residual entropy of superheated vapor for pure compounds 18 ijcpe vol.13 no.2 (june 2012) -available online at: www.iasj.net four changes represented by the sequence of isothermal and isobaric steps:         1111122212 ssssssssss vvigigigig  …(42)  step 1 → 1 v : the transformation of saturated liquid at (t1, p1) to saturated vapor at t1 and p1: v v sss  11 saturated entropy of vapor can be calculated by converting saturated liquid at reference t and p to saturated actual gas at the same t and p by using the entropy of vaporization at the normal boiling point δs v after scaling it with the reference temperature by watson relation [15] 38.0 2 1 2 1 1 1              tr t h h r v v ...(43) in ref. [13], some of the better estimation methods were tested for several different compounds as hydrocarbons, alcohols, rare gases, oxides and other polar compounds and useful comparison between these methods (giacalone, riedel, chen, and vetere) and experimental values of δhv were obtained. this comparison shows that the average absolute percentage error of giacalone, riedel, chen, and vetere methods are 2.8, 1.8, 1.7, and 1.6, respectively. therefore, the present investigation employs the more accurate one vetere method eq. (44) to calculate δh v at the normal boiling point and it is scaled with eq. (43) 21 15075.037306.037691.0 89584.069431.0ln4343.0     brcbr brc brcvb tpt tp trth …(44) to obtain δhv at the reference temperature, then calculating δsv by dividing δhv by the reference temperature. fig.2, calculational path for entropy change  step 1 v → 1 ig : a hypothetical process that transforms a real gas into an ideal gas at t1 and p1 by using suitable residual entropy of an equation of state. rvig sss 111   step 1 ig → 2 ig : changes in the idealgas state from (t1, p1) to (t2, p2). for this process: 1 2 12 ln 2 1 p p r t dt csss t t ig p igigig   in the present work cp ig is calculated by: 4 4 3 3 2 210 tatatataa r c ig p  ...(45) this polynomial provides simplicity in use and it also covers good range of temperatures. the data related to eq. (45) for some pure compounds are listed in (appendix asection c) of ref. [13].  step 2 ig → 2: another hypothetical process that transforms the ideal gas back into a real gas at t2 and p2: mahmoud o. a bdullah, sarmad t. najim and shahad z. atta -available online at: www.iasj.net ijcpe vol.13 no.2 (june 2012) 19 rig sss 222  therefore, equation (42) is the result of the totality of the entropy changes for the above four steps. selecting the optimum eos for the present work [19] the conflict between accuracy and simplicity is a big dilemma in the development of an equation of state. despite the wide use of high-speed computers, the simplicity is still highly desired for easy and unequivocal applications of the equation to complex problems. so, for most calculations, the empirical approach is often better than the more complex theoretical approach in view of accuracy as well as minimum data requirements. often, virialequation – which truncates to second or to third term – can only be considered useful from the first form and employed in the present work. in addition to the soave-redlich-kwong equation (srk) and peng-robinson equation (pr) as the models of cubic equations of state from the second form which have valuable applications in most common use today, lee and kesler equation represents –although it is including some complexity– the easiest example of the third form that was also used in the present work. the average absolute deviation for residual entropy aad in (j/mol.k) is defined as follows: n ss aad calculated r erimental r    )( exp ...(46) aad is considered as a factor for a comparison between the different methods that were used for calculating actual residual entropy of superheated vapor for different compounds. it is calculated in (j/mol.k) because when it is calculated in (j/g. k) it was very decimal and the imparity of deviations of using the equations was not perceptible. also, the dimensionless deviation can be obtained by dividing aad by r (gas constant) which is denoted by aad/r. in addition, the average absolute percentage deviation for entropy aad% is defined as follows: n sss aad erimentalcalculatederimental %100/)( % expexp    ...(47) which is considered as a factor for comparison between the different methods that were associated in determining the actual entropy of superheated vapor for different compounds. results and discussion [19] 1. application of the eos for compounds 1.1. classification of the application of eos into regions five different equations of state were applied for calculating residual entropy (s r ) in comparison for all experimental data of pure compounds that supported the present investigation as expressed earlier. to have an insight of the precision of these equations with the range of tr and pr, a summary of the results classified into three regions is presented as follows: region 1) tr < 1, and pr < 1 include 14 compounds involving 859 experimental data points (9 nonpolar compounds with 431 experimental data points and 5 polar compounds with 428 experimental data points) from the 2791 experimental data points of the all 20 compounds. region 2) tr > 1, and pr < 1 include the 20 compounds involving 1501 prediction and correlations of residual entropy of superheated vapor for pure compounds 20 ijcpe vol.13 no.2 (june 2012) -available online at: www.iasj.net experimental data points (14 nonpolar compounds with 921 exp. data points and 6 polar compounds with 580 exp. data points) from the all 2791 exp. data points of the all 20 compounds. region 3) tr > 1, and pr > 1 include 13 compounds involving 431 experimental data points (10 nonpolar compounds with 308 experimental data points and 3 polar compounds with 123 experimental data points) from the all 2791 experimental data points of the all 20 compounds. although this region represents the supercritical region, but the knowledge of the accuracy of employing these equations in comparison with the accuracy of the modified equation in the present work for this region is advantageous for some available experimental data. 1.2. total region this region represents all three regions and consists of 20 compounds involving 2791 experimental data points (14 nonpolar compounds with 1660 experimental data points and 6 polar compounds with 1131 experimental data points). 2. modification of eos [19] 2.1. selecting the optimum eos for the modification although lee-kesler equation proved to be better than soave-redlichkwong, peng-robinson, and virial equations for the prediction of residual entropy of superheated vapor for the most of compounds used in this investigation, but it is more useful if the errors can be reduced to value less than those obtained with lee-kesler equation. the modification of any equation is usually done for the equation that proved to be the most accurate. the more accurate one is lee-kesler equation, but it is very difficult to modify it, so soave-redlich-kwong equation which is the nearest one in accuracy to the lee-kesler equation was selected for modification. table 2, the existence of the compounds in three regions 2.2. modification of soave-redlich kwong equation [19] soave-redlich-kwong equation was derived mainly to calculate vapor-liquid equilibria, so all attention was concentrated on that purpose in its derivation, and therefore, there is still room for improving it for superheated vapor. the modification would be based on modifying α parameter of srk equation which is the function of reduced temperature and also on n o n p o la r c o m p o u n d s re g io n s n o n p o la r c o m p o u n d s re g io n s 1 argon 1, 2, 3 12 n-hexane 1, 2, 3 2 methan e 2, 3 13 n-heptane 1, 2, 3 3 oxygen 2, 3 14 n-octane 1, 2, 3 4 nitroge n 2, 3 p o la r c o m p o u n d s re g io n s 5 ethane 2, 3 6 cyclopropane 1, 2 1 refrigera nt 12 1,2 7 propane 1, 2, 3 2 isopentan e 2, 3 8 acetyle ne 1, 2 3 ammonia 1, 2 9 neopentane 1, 2 4 refrigera nt 152a 1, 2 1 0 benzene 1, 2 5 refrigera nt 134a 1, 2, 3 1 1 carbon dioxide 2, 3 6 water 1, 2, 3 mahmoud o. a bdullah, sarmad t. najim and shahad z. atta -available online at: www.iasj.net ijcpe vol.13 no.2 (june 2012) 21 acentric factor which is included in parameter n:   25.011 r tn  srk eq. parameter …(7a) figs. (2) to (5) show clearly that the values of pressures or reduced pressures influence the value of α although the temperature is constant. thus α in soave equation can be considered a function of temperature, pressure and acentric factor and its equation would be written as [19]:   21  n new form of α parameter ...(48a)  4 4 4 31 52 prpr   trgtrgg gg ...(48b) the coefficients of this equation had been determined by using statistical methods. these coefficients were calculated with the aid of computer program on non-linear estimation of statistica software fitting to minimize the error obtained for calculating new α for two selected compounds. in the present work, n-octane and water were used in the fitting. by trying many different equations, it was found that equation (48b) was the optimum equation for predicting γ with lowest error. the coefficients of eq. (48b) are listed in table (3). table 3, coefficients of equation (48b) the modification was made by comparing the experimental values of residual entropy of superheated vapor with the values calculated by soave equation which was obtained by using all original parameters of soave equation except γ parameter which is inserted in the computer program empirically and remain varying until the deviation between the inserted value of γ with the calculated value by soave equation for each experimental data pointapproached to zero (% error of (s r exp.-s r cal.) ≤ 0.00001). the new equation of α gives a higher accuracy where the overall aad was 2.4621 j/mol.k for residual entropy and the (aad%) was 1.1083 for entropy, for all compounds studied in the present work. the main reason for choosing the mentioned two compounds (n-octane, and water) in the fitting of the experimental data was due to their molecular nature that n-octane represents the normal nonpolar gases which was considered having the highest ω > 0 in comparison with the other used compounds in the present work and thus to be able of controlling the other compounds of less ω and has no polarity properties found (χ = 0). on the other hand, water represents the polar compounds which have in addition to ω > 0 the polarity properties χ > 0 and also it has the highest χ among others. the only way for obtaining the experimental values of the parameter γ is by all empirical trial and error method which needs great time to obtain any value. therefore, the modification was limited to only these mentioned two types of gases which were used to predict the new α parameter equation that gives more accuracy in calculating s r and s for all data points (2791) experimental data points for all 20 nonpolar and polar gases employed in the present work. c o e ff ic ie n t value c o e ff ic ie n t value g1 -0.920338 g4 0.370002 g2 -0.034091 g5 0.9906321 g3 0.064049 ------ prediction and correlations of residual entropy of superheated vapor for pure compounds 22 ijcpe vol.13 no.2 (june 2012) -available online at: www.iasj.net fig.2, the relation between the values of parameter α and pr for n-octane at tr =1.3 fig.3, the relation between the values of parameter γ and pr for n-octane at tr =1.3 fig.4, the relation between the values of parameter α and pr for water at tr =1.349 fig.5, the relation between the values of parameter γ and pr for water at tr =1.349 table 4a, summary of application of eos through 3 regions individually 0.0 0.5 1.0 1.5 2.0 pr -0.4 0.0 0.4 0.8 1.2  experimental values soave equation present work 0.0 0.5 1.0 1.5 2.0 pr -1.20 -0.80 -0.40 0.00  experimental values soave equation this work 0.0 0.5 1.0 1.5 2.0 2.5 3.0 pr -0.2 0.0 0.2 0.4 0.6 0.8  experimental values soave equation this work 0.0 0.5 1.0 1.5 2.0 2.5 3.0 pr -1.2 -0.8 -0.4 0.0  experimental values soave equation this work region 2 at (tr > 1 and pr <1 ) no. of points in region 2 is (1501) equations used aad for s r (j/mol. k) aad/r for s r aad% for s l-k 3.9300 0.4727 1.7892 p-r 4.1422 0.4982 1.8790 virial truncated to b) 4.3718 0.5258 2.0988 virial truncated to c) 4.3709 0.5257 2.1102 s-r-k 4.0144 0.4828 1.8171 this work 2.4077 0.2896 1.1475 region 3 at (tr > 1 and pr >1 ) no. of points in region 3 is (431) equations used aad for s r (j/mol. k) aad/r for s r aad% for s l-k 2.9571 0.3557 1.5221 p-r 4.7524 0.5716 2.7529 virial truncated to b) 6.4233 0.7726 4.6412 virial truncated to c) 6.9797 0.8395 5.0765 s-r-k 3.5325 0.4249 2.1336 this work 1.7430 0.2096 0.9935 region 1 at (tr < 1 and pr <1 ) no. of points in region 1 is (859) equations used aad for s r (j/mol.k ) aad/r for s r aad% for s l-k 4.8377 0.5819 1.7033 p-r 5.2743 0.6344 1.9060 virial truncated to b) 5.2816 0.6353 1.9657 virial truncated to c) 5.2197 0.6278 1.9547 s-r-k 5.1998 0.6254 1.8723 this work 2.9180 0.3510 1.0974 mahmoud o. a bdullah, sarmad t. najim and shahad z. atta -available online at: www.iasj.net ijcpe vol.13 no.2 (june 2012) 23 table 4b, summary of application of eos through whole regions. (from tr < 1 & pr <1 to tr > 1 & pr >1 ) discussion the entropy of a pure compound cannot be directly measured but is calculated from other properties. it is a function of both temperature and pressure; in general, it increases with the increase in temperature and decreases with the increase in pressure at constant temperature. at zero pressure, all gases behave ideally, and the ideal gas state entropy is remaining dependent on pressure. the residual entropy term s-s ig is the difference between the entropy of a compound at certain p and t and that of an ideal gas state at the same conditions. in the absence of p-v-t data for the compounds of interest, or if the data do not cover the conditions under which engineering calculations are to be made, generalized correlations which express z as a function of tr and pr were found to be of great value in estimating residual properties as residual entropy based on a modified theory of corresponding states. the usual method available for predicting the residual entropy of superheated vapor for pure compounds is by employing the equation of state. in the present work the equations of state employed were: l-k, p-r, s-r-k, and virial truncated to second and to third terms equations. it is well known that the evaluation of any correlation or prediction method is done by comparing the calculated values for any equation used with those of the experimental data normally limited and mostly not covering wide range of temperatures and pressures for any certain compound. the deviation between the experimental data and results of prediction or correlation method determines the accuracy of the method and this accuracy in the present work was represented as mentioned in the previous section by aad% for entropy and aad j/mol.k for residual entropy. tables (4a) and (4b) show the aad% and the aad in j/mol.k for the calculated entropy and calculated residual entropy respectively of the superheated vapor for nonpolar and polar compounds as compared with experimental values. 1. comparison of the results with the experimental data [19] comparing the results that are shown in tables (4a) and (4b) indicate that the l-k equation gives higher accuracy for predicting sr as compared with the pr, virial truncated to second or third terms, and s-r-k equations using the experimental data points of the present study. the aad% for calculating the entropy of superheated vapor for 14 nonpolar compounds of 1660 data points are 1.389%, 1.397%, 1.4918%, 1.5237%, and 1.3799% when using lk, p-r, virial truncated to second or third terms, s-r-k respectively, while the aad for calculating the residual entropy of superheated vapor of these compounds by using these equations are 4.6277, 4.9243, 4.9782, 4.9501, and 4.7665 j/mol.k respectively. further more the aad% for calculating the entropy of superheated vapor for 6 polar compounds of 1131 data points are 2.2096%, 2.9399%, 3.8575%, all regions (1, 2, and 3) no. of points for all regions (2791) equations used aad for s r (j/mol. k) aad/r for s r aad% for s l-k 4.0591 0.4882 1.7215 p-r 4.5849 0.5515 2.0223 virial truncated to b) 4.9686 0.5976 2.4505 virial truncated to c) 5.0350 0.6056 2.5204 s-r-k 4.3084 0.5182 1.8850 this work 2.4621 0.2961 1.1083 prediction and correlations of residual entropy of superheated vapor for pure compounds 24 ijcpe vol.13 no.2 (june 2012) -available online at: www.iasj.net 3.9833, and 2.6263% when using l-k, p-r, virial truncated to second or third terms, s-r-k respectively, while the aad for calculating the residual entropy of superheated vapor of these compounds by using these equations are 3.2247, 4.0867, 4.9546, 5.1597, and 3.6359 j/mol.k respectively. the aad% for calculating the entropy of superheated vapor for all the compounds of 2791 data points are 1.7215%, 2.0223%, 2.4505%, 2.5204%, and 1.8850% when using l-k, p-r, virial truncated to second or third terms, s-r-k respectively, while the aad for calculating the residual entropy of superheated vapor of these compounds by using these equations are 4.0591, 4.5849, 4.9686, 5.0350, and 4.3084 j/mol.k, respectively. 2. the modified equation [19] although the better results were obtained by l-k equation, but this equation is sometimes not very preferable, because it needs more time and not easy to apply as cubic equations of state.s-r-k equation showed also a very good accuracy closest to that of the l-k equation in calculating the residual entropy s r of superheated vapor. thus efforts were directed to modify s-r-k equation to increase its accuracy as much as possible and to be more accurate than the original soaveredlich-kwong and even the l-k equation. this may be done by using a statistical program and statistical methods that give the suitable form of correlation. many attempts were done to develop s-r-k equation to this purpose, and the best correlation of this modification was obtained in section 3.6 which proved a very good accuracy for most compounds under study. the modification was applied for 20 pure compounds of 2791 experimental data points (nonpolar and polar compounds). it reduced the aad% and aad of soave-redlich-kwong equation for 1660 experimental data points of 14 nonpolar compounds from 1.3799% to 0.9592% and from 4.7665 to 2.8247 j/mol.k, respectively. while it reduced the aad% and aad of soave-redlich-kwong equation for 1131 experimental data points of 6 polar compounds from 2.6263% to 1.3270% and from 3.6359 to 1.9299 j/mol.k, respectively. on the other hand, it reduced the aad% and aad of soave-redlich-kwong equation for all the 20 pure compounds under study from 1.8850% to 1.1083% and from 4.3084 to 2.4621 j/mol.k respectively as shown in table (4b). examples of nonpolar compounds: for octane, the aad% and aad by using srk equation were 2.0085% and 12.0160 j/mol.k respectively, while they were 0.3711% and 2.1418 j/mol.k respectively when using the modified srk equation. for nitrogen, the aad% and aad by using srk equation were 0.4308% and 0.7276 j/mol.k respectively, while they were 0.2925% and 0.4956 j/mol.k respectively when using the modified srk equation. :ompoundscolar pexamples of for water, the aad% and aad by using srk equation were 5.1695% and 6.2356 j/mol.k respectively, while they were 2.4539% and 3.2028 j/mol.k respectively when using the modified srk equation. for refrigerant (134a), the aad% and aad by using srk equation were 3.0307% and 5.8645 j/mol.k respectively, while they were 1.2397 % and 2.3752 j/mol.k respectively when using the modified srk equation. for polar compounds when applying the modified srk equation without considering polarity effect term, the deviation from the experimental data was more than that when considering mahmoud o. a bdullah, sarmad t. najim and shahad z. atta -available online at: www.iasj.net ijcpe vol.13 no.2 (june 2012) 25 polarity effect term as shown in tables (4a) and (4b). although this increase was not very significant, but in practical use more accuracy is desirable. the interesting features of the developed equation in the present work for calculating the residual entropy are: 1. it is a rather simple equation that achieved good results for both nonpolar and polar compounds. 2. it needs only well-known properties of pure compounds (tc, pc, ω, and for polar compounds χ) for each compound. the new correlation gives very good accuracy for calculating s r of the compounds shown in tables (4a) and (4b) by a comparison with the experimental data approximately over the whole temperature and pressure ranges tested. where the conditions tested for temperature are up to tr > 2 and for pressure raised for some compounds are up to pr > 2. figures (2) to (5) show the relation either between residual entropy with pressure at constant temperature or between residual entropy with temperature at constant pressure for the results obtained using this new method of correlation and other equations used comparing with the experimental data. tables (4a) and (4b) show the comparison of the results of deviations from the experimental data of n-octane and water when using lee-kesler, peng-robinson, soave-redlich-kwong equations of state, and the new correlation of this work. although virial equation was employed in this study but its results showed high deviations from the experimental values obtained in comparison with deviations of other equations employed. conclusions 1. different equations of state were used to predict the residual entropy of superheated vapor for pure compounds. they are lee-kesler, peng-robinson, soave-redlichkwong and virial truncated to second and to third terms equations of state. the results indicate that lee-kesler equation is the most accurate equation among these five equations, srk equation is the closest one in its accuracy to the lee-kesler, and the virial equation (truncated to second or to third terms) gave highest deviations from the experimental values which prescribed the need to listing its results in tables. 2. new modification was made by redefining the parameter α in soave equation to be a function of reduced pressure, acentric factor, and polarity factor for polar compounds in addition to be the original function of reduced temperature and n parameter –which is also the function of acentric factor– by using statistical methods. this correlation is as follows:   2n1      4996932.0 r 4 r 34091.0 r trp 370002.0t064049.0p920338.0 a. the aad of 1660 experimental data points of 14 pure nonpolar compounds obtained from this correlation was 2.8247 j/mol.k in comparison with those obtained from lee-kesler, peng-robinson, virial truncated to second and to third terms, and soave-redlich-kwong methods were 4.6277, 4.9243, 4.9782, 4.9501, and 4.7665 j/mol.k, respectively. b. the aad of 1131 experimental data points of 6 pure polar compounds obtained from this correlation was 1.9299 j/mol.k, in comparison with those obtained when using the same equations above were 3.2247, prediction and correlations of residual entropy of superheated vapor for pure compounds 26 ijcpe vol.13 no.2 (june 2012) -available online at: www.iasj.net 4.0867, 4.9546, 5.1597, and 3.6359 j/mol.k respectively. c. the aad of 2791 experimental data points of all the 20 pure compounds obtained from this correlation was 2.4621 j/mol.k in comparison with those obtained from lee-kesler, peng-robinson, virial truncated to second and to third terms, and soave-redlich-kwong methods were 4.0591, 4.5849, 4.9686, 5.0350, and 4.3084 j/mol.k, respectively. acknowledgement to all these who try to understand the philosophy of entropy and interpret why it intrudes in everything in our lives nomenclature variable notations a, b, constants used in the cubic eos, eq.(4) and eq. (11), b, b', second virial coefficient, cm 3 /mol 2 , b, c, d, coefficients of eq.(23), c, c', third virial coefficient, cm 6 /mol 3 , cp, heat capacity at constant pressure, j/mol.k, g1,g2,..g5, coefficients of eq. (48b), n, constant used in the cubic eos, eq.(4) and eq. (11), p, pressure, kpa, r, universal gas constant, j/mol.k,, s, entropy, j/mol.k, t, temperature, k, v, volume,m 3 , z, compressibility factor. abbreviations ad, absolute deviations for s r ,j/(mol.k), ad%,absolute percentage deviation for s, ad/r, absolute deviation for s r divided by r, aad, average absolute deviation for s r ,j/(mol.k) aad%, average absolute percentage deviation for s, aad/r, average absolute deviation per r for s r , eos, equation of state, lk, leekesler equation, m.wt., molecular weight, pr peng-robinson equation, rk, redlich-kwong equation, ref., reference, srk, soave-redlich-kwong equation. greek letters α, constant used in cubic equations of state, β, parameter used in equation (257)., γ, constant used in equation (18), γ, parameter used in equation (48a), ω, acentric factor.,χ, polarity factor of eq. (40). superscripts ig, ideal gas, r, residual, sat., saturated state, (0), simple fluid equation (17), (r), reference fluid equation (17). subscripts b, boiling point, c, critical property , cal., calculated value, exp.,=,experimental value, g, gas state, l, liquid state, r, reduced property r, reference fluid, v, vaporization. references 1. moran, m. j., shapiro, h. n., munson, b. r., and de witt, d. p., (2003) “introduction to thermal systems engineering” john wiley and sons, inc., 2. cengel, y. a., and boles, m. a., (1998) “thermodynamics: an engineering approach” 3 rd edition, mc graw hill. 3. moran, m. j., and shapiro, h. n., (2000) “fundamentals of engineering thermodynamics” 4 th edition, john wiley and sons, inc. 4. tsonopoulos, c., (1974) “an empirical correlation of the second virial coefficients” aiche j., vol. 20, no. 2, 263-272. 5. soave, g., (1972) “equilibrium constants from a modified redlichkwong equation of state” chem. eng. sci., vol. 27, pp. 1197-1203. 6. soave, g., (1983) “improvement of the van der waals equation of mahmoud o. a bdullah, sarmad t. najim and shahad z. atta -available online at: www.iasj.net ijcpe vol.13 no.2 (june 2012) 27 state” chem. eng. sci., vol. 39, no. 2, pp. 357-369. 7. assael, m. j., trusler, j. p. m., and tsolakis, t. f., (1996) “thermophysical properties of fluids”. 8. peng, d. y., robinson, d. b., (1976) “a new two-constant equation of state” ind. eng. chem. fundam., vol. 15, 59. 9. lee, b. i., and kesler, m. g., (1975) “ a generalized thermodynamic corre-lation based on threeparameter corresponding states” aiche j., vol. 21, no. 3, 510-527. 10. pitzer, k. s., lipmann, d. z., curl, r. f., jr., huggins, c. m., and petersen, d. e., (1955) “the volumetric and thermodynamic properties of fluids ii. compressibility factor, vapor pressure and entropy of vaporization” american chemical society, 77, 3433 11. edmister, w. c., and lee, b. ik., (1984) “applied hydrocarbon thermo-dynamics” vol. 1, 2nd edition, gulf publishing company. 12. paul, b. j., and francis, o., (1985) “computer aided chemical thermodynamic of gases and liquids – models programs” john wily and sons. 13. poling, b. e., prausnitz, j. m., and o’connell, j. p., (2001) “the properties of gases and liquids” 5th edition, mcgraw-hill. 14. santis, r. d., and grande, b., (1979) “an equation for predicting third virial coefficients of nonpolar gases” aiche j., vol. 25, no. 6, 931-938. 15. smith, j. m., van ness, h. c., and abbott, m. m., (2001) “introduction to chemical engineering thermodynamics” 6th edition, mcgrawhill. 16. eubank, p. t., and angus, s., (1973) “truncation of virial equations in pvt data reduction” journal of chemical and engineering data, vol. 18, no. 4, 428-430. 17. halm, l. r., and stiel, l. i., (1967) “a fourth parameter for the vapor pressure and entropy of vaporization of polar fluids” aiche j., 13, 351. 18. kukoljac, m. d., and grozdanic, d. k., (2000) “new values of the polarity factor” j. serb. chem. soc., vol. 65, 12, 899-904. 19. al-najjar, sh. z., (2009), "prediction and correlations of residual entropy of superheated vapor for pure compounds" m. sc. thesis, nahrain university. iraqi journal of chemical and petroleum engineering vol.13 no.4 (december 2012) 2733 issn: 1997-4884 estimation of the rock mechanical properties using conventional log data in north rumaila field wafa al-kattan and n. jasim al-ameri university of baghdad, college of engineering, petroleum engineering department abstract hydrocarbon production might cause changes in dynamic reservoir properties. thus the consideration of the mechanical stability of a formation under different conditions of drilling or production is a very important issue, and basic mechanical properties of the formation should be determined. there is considerable evidence, gathered from laboratory measurements in the field of rock mechanics, showing a good correlation between intrinsic rock strength and the dynamic elastic constant determined from sonic-velocity and density measurements. the values of the mechanical properties determined from log data, such as the dynamic elastic constants derived from the measurement of the elastic wave velocities in the material, should be more accurate than that determined by direct strength tests with core samples. this can be attributed to the scale effect and sampling disturbances. the aim of this study was to present methods of determining measures of some mechanical properties, from available well log data (conventional sonic, density, and gamma ray) for a well in north rumaila field. the mechanical properties include formation strength and poisson’s ratio. for the formation strength, combined elastic modulus (ec) and shear modulus (g) were determined. the poisson’s ratio was determined by using three different techniques to permit the accuracy of their values. the elastic modulus, shear modulus, and poisson’s ratio were then correlated with depth and effective stress. the results show that combined correlations are important source of the prediction of overpressure zones which represent a major problem encountered in drilling and production process. kew word: mechanical properties, north rumaila field, elastic modulus, shear modulus, poisson’s ratio, effective stress introduction effective stress laws and their applications are not new, but are often overlooked or miss-applied. at depth reservoir rocks are subjected to in-situ stress arising from the combined effects of overburden pressure (external stress), which is exerted by the weight of overlying rocks; tectonic stresses that are generated by the large-scale movements in the earth crust; and pore pressure that is exerted by the fluids present in the rock pores. iraqi journal of chemical and petroleum engineering university of baghdad college of engineering estimation of the rock mechanical properties using conventional log data in north rumaila field 28 ijcpe vol.13 no.4 (december 2012) -available online at: www.iasj.net it is common practice to choose a net effective stress that is thought to result in identical rock properties. according to terzaghi [1] , an effective stress law is a mean to convert two variables, external stress (σ) and pore pressure pp, into one equivalent variable (σeff): σeff = σ -α pp where α is the effective stress coefficient (biot constant) which is assumed to be 1.0 at high pressure. normal pressure refers to formation pressure which is approximately equal to the hydrostatic head of a column of water of equal depth (approximately 0.465 psi/ft depth). formation with pressure higher than hydrostatic is referred as bring abnormally pressured. high formation pressures cause major changes in subsurface-rock parameters. in over pressured shales, the acoustic velocity and density are lowered and porosity is higher than that in normal pressures. because formation-fluid pressure, in an abnormal pressure zone, is increased the effective stress is expected to decrease. the aim of this study is to draw attention to the potential impact of very high pore pressure on rock mechanical properties. the effects of effective stress decreasing on the compressional wave velocity (vp), combined elastic modulus (ec), shear modulus (g), and poisson’s ratio for the studied aria, a deep well in north rumaila, were determined. direct measurements of rock strength and poisson’s ratio are not easily obtained for typical hydrocarbon wells, so it is of interest to develop means of obtaining them indirectly from more easily available measurements. one such possible source is from wireline logging data, principally, the sonic, density, and gamma ray logs. poisson’s ratio should, in principle, be derivable from the sonic compressional and shear wave velocities, vp and vs respectively. because vs is not available, alternative methods were used to estimate values of poisson’s ratio. the studied interval, ranges from 2000 to 5200 m, passes through many complex formations. the formation materials include limestone, dolomite, anhydrite, and some sand enterbeded with beds of shale and salt. the results of the derived mechanical properties of the studied interval were correlated with depth and effective stress; the abnormal pressure zone can be detected easily from the correlations. good correlation between effective stress and poisson’s ratio is observed in abnormal interval zone. modulus properties modulus values have been used as a measure of the strength properties and stability of rocks under different conditions of drilling and production. the combined elastic modulus ,ec [2] , take in to consideration the effect of both shear modulus g and bulk modulus kb,is given by: ec = g + kb …(1) where, g is the shear modulus in psi of a material, subjected to a given total load, defined as the ratio of shear load to lateral deformation. alone, g is serving as a direct measure of the strength of the formation solids. the bulk modulus kb is the reciprocal of bulk compressibility, its value depends on the compressibility of both formation solids and fluids. the log data were used to calculate the combined elastic modulus from the equation: wafa al-kattan and n. jasim al-ameri -available online at: www.iasj.net ijcpe vol.13 no.4 (december 2012) 29 ec = …(2) where: tc is transit time from sonic log, ⁄ tc = p is the compressional wave velocity ft s is bul density from density log gm cc effective stress provided by the overburden weight may be determined from the equation: =d (gov – gp) … (3) where: σ = effective stress provided by overburden weight, psi d = depth, ft gov = overburden weight gradient, psi gp = fluid pressure gradient, psi from the correlation, given in fig-a [2] , between ec and kb the value of kb was estimated, then the value of g is calculated using equation (1). fig. a, estimating the bulk modulus the estimated shear modulus, g, is a measure of the formation strength by itself. poisson’s ratio, υ, then may be expressed in terms of the following modulus [2] : υ = … (4) anderson et al [3] have presented an empirical relationship relating poisson s ratio to shaliness given by: υ = 0.125q + 0.27 …(5) where q is the shaliness index and has been defined as: q = …(6) where ϕs is porosity from sonic log ϕd is porosity from density log poisson’s ratio calculated by equation (5) was used to calculate, again, the shear modulus g by the relation [4] : g = … (7) where a = using the concept of a variable overburden pressure eaton [5] calculate the poisson’s ratio by the equation: pf = pp + … (8) where pf =fracture pressure, psi pp = pore pressure, psi po = overburden pressure, psi υ =poisson’s ratio in terms of pressure gradient, the above equation may be expressed as: … (9) y = 0.5818x + 0.4318 r² = 0.993 0 2 4 6 8 10 12 0 5 10 15 20 based on published data combined modulus, (ec)ϭ=0,psi*106 b u lk m o d u lu s, (e b ) ,s p i* 1 0 6 estimation of the rock mechanical properties using conventional log data in north rumaila field 30 ijcpe vol.13 no.4 (december 2012) -available online at: www.iasj.net where: gf = pressure fracture gradient, psi ft gp= pore pressure gradient, psi ft gov= overburden pressure gradient, psi ft the value of the fracture pressure gradient, gf, was measured from the dst. the pore pressure gradient gp calculated by the equation of pore pressure prediction [6] , as: gp = gov – (gov – gpn) 3 where: gpn= normal pore pressure gradient (0. 5), psi ft tn= the normal travel time, s ft to = the shale travel time, s ft the overburden pressure gradient calculated by the equation: gov = * 0.433 the determined poisson’s ratio, depending on pressure gradients, was used to calculate the shear modulus g again. the calculated variables, vp,ec,and g (g was calculated by three methods),and poisson’s ratio (calculated by three methods) were plotted against the depth and the effective stress. results and discussions a reservoir rocks is subjected to external (overburden) and internal (pore fluid) pressures. laboratory measurements [7] have shown that the acoustic velocity, vp, is affected by the effective stress, which is the difference between external internal pressures (δp), rather than the absolute value of external pressure or the internal pressure. compressional wave velocity, vp, increase as the δp increases. because δp determines the degree of rock compactions and its bulk modulus, it follows that vp depends on compaction. the more compacted the rock the higher its acoustic velocity. also the acoustic velocity depends on the elastic properties of rocks, so the combined elastic modulus, ec, compressional wave velocity, vp, are correlated with depth (as shown in fig. 1). fig. 1, correlation between compressional wave velocity & elastic modula with depth fig. 2, poisson's ratio correlation comparison for the studied well 2000 3000 4000 5000 6000 0 10 20 30 ec,*(10^6) vp*(10^4) ec*(10^6) & vp(10^4) depth top of abnormal 2000 3000 4000 5000 6000 0.15 0.25 0.35 0.45 v,eaton v,anderson v,elastic modula poisson's ratio depth,m wafa al-kattan and n. jasim al-ameri -available online at: www.iasj.net ijcpe vol.13 no.4 (december 2012) 31 in fig.2 poisson’s ratio,calculated by three different methods, was correlated with depth. the shear modulus, also calculated by three methods, was correlated with depth in fig.3. fig. 3, the correlation between shear modulus & depth for the studied well the trends of increasing vp, ec, g, and υ with depth is obvious, and the abnormal pressure zone can be detected between 3200 and 5200 m depth. to show the effect of the effective stress, δp, on p, ec, g, and υ, the normal interval, fig(4-5), and abnormal pressure intervals (fig. 6 to 9) were separated . in fig. 4, the normal zone, the effect of lithology on vp, ec, g is more than the effect of effective stress since the important factor here is the rock density. any increase in bulk density, grain size would cause an increase in vp, but its influence on the strength of the rock is small. fig. 4, the correlation between elastic modulus ec , shear modulus g , compressional wave velocity vp with effective stress ϭo in the normal zone fig. 5, the correlation between effective stress & poisson’s ratio in the normal zone in figs. 6,7,8, and 9,(the abnormal zone) the effective stress was correlated with ec, g, and vp. 2000 2500 3000 3500 4000 4500 5000 5500 0 2 4 6 8 g,anderson g,elastic g,eaton shear modulus,psi,*10^6 depth, 800 850 900 950 1000 1050 1100 1150 1200 1250 1300 1350 1400 1450 1500 1550 1600 1650 1700 1750 0 5 10 15 ec,*10^6 g(eaton),*10^6 g(anderson),* 10^6 g (elastic),*10^6 ec & g, *(10^6) &vp *10^4 e ffe ctive stre ss,p si 0.1 0.15 0.2 0.25 0.3 0.35 0.4 600 1100 1600 2100 v,elastic v,eaton v,anderson effective stress,psi p o isso n 's ra tio normal estimation of the rock mechanical properties using conventional log data in north rumaila field 32 ijcpe vol.13 no.4 (december 2012) -available online at: www.iasj.net fig. 6, correlation between compressional wave velocity vp & effective stress ϭo in the abnormal zone fig. 7, the correlation between elastic modula ec & effective stress ϭo in the abnormal zone fig. 8, the correlation between shear modulus & effective stress ϭo in the abnormal zone fig. 9, the correlation between effective stress & poisson’s ratio in the abnormal zone fig. 10, effect of different pressure gradient for normal and abnormal zone the scattering, shown in these figures, is due to the influence of both the complicated lithology and effective stress. this is very clear in fig. 10 which shows that the increasing in gov (its value depends mainly on bulk density) is very small comparing to 0 0.5 1 1.5 2 2.5 0 1000 2000 effective stress v p * 1 0 ^ 4 0 2 4 6 8 10 12 14 16 18 20 0 1000 2000 effective stress e c,* 1 0 ^ 6 0 1 2 3 4 5 6 7 8 0 1000 2000 g,eaton g,anderson g,elastic effective stress g , * 1 0 ^ 6 y = 1e-10x3 6e-07x2 + 0.001x 0.0533 r² = 0.7739, eaton 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 200 700 1200 1700 2200 v,eaton v,anderso n effective stress,psi p o isso n 's ra tio 2000 2500 3000 3500 4000 4500 5000 5500 0 0.10.20.30.40.50.60.70.80.9 1 1.11.2 gov gp effective stress gradient gov, gp, effective stress (psi/ft) d e p th ,m top of abnormal wafa al-kattan and n. jasim al-ameri -available online at: www.iasj.net ijcpe vol.13 no.4 (december 2012) 33 that of gp, and the effective stress decreasing is great. the correlation between poisson’s ratio and effective stress in fig. 5&9 support the above illation. the estimation of poisson’s ratio, in the normal zone, depending on eaton’ s equation show that the increase in effective stress dose not affects the value of poisson’s ratio. while the value estimated from the other models, which depend on shale index, show deviations correlated with lithology changes. the higher poisson’s ratio of limestone comparing to that of anhydrite, sandstone, shale, and salt, may be the main cause of this deviations. in the abnormal pressure zone, the effect of both the effective stress and lithology are clear. the scattering is due to the decrease of effective stress, which has influence on the dynamic elastic parameters, the higher the value of poisson’s ratio of a sediment the more vertical matrix stress is transmitted in the horizontal direction. in overpressured shales sonic velocity and density are lower and porosity is higher than in normal pressure. in fig.9, good correlation between the effective stress and poisson’s ratio is observed when depending on eaton equation. again the scattering is great depending on the other methods. conclusion in this work, we have investigated whether we can derive correlations between petrophysical and mechanical properties using wireline log data. neglecting the pressure effect on velocity result in over estimation of rock porosity by sonic log in over pressured formations, and under estimation of porosity in pressure depleted zones. the effective stress coefficient (biot constant in terzaghi equation) assumed to be equal to 1 but it can different and more attention should be given to this constant. the mechanical properties of rocks can be used very effectively in the planning of drilling a well. the rock strength, determined from shear modulus (g) and poisson’s ratio (ѵ), can be used to estimate the rate of penetration (rop) and bit wear. more knowledge is necessary in order to get batter correlations between petrophysical and mechanical properties for iraqi oil field. references 1. terzaghi, ., and pec , r., b.,”soil mechanics in engineering practice,” john wiley&sons, inc., n.,y., 1984 (566). 2. nathan stein: “mechanical properties of friable sands from conventional log data,” spe no.5500 (1975). 3. anderson, r. a., ingram, d. s., and zainer, a. m.: “fracture pressure gradient determination from well logs,” spe-aime meeting, (oct, 1972, 8-11). 4. m. p. tixier, g.w. lovelesss, r.a. anderson "estimation of formation strength from the mechanical properties log". spe 4532 (1973) 5. ben a.eaton,”fracture gradient prediction and its application in oilfield operation”.jpt(oct.19 9) 1353;trans.,aime, 246. 6. ben a. eaton and travis l. eaton, “fracture gradient prediction for the new generation”. world oil (oct. 1997) 93. 7. john l. shafer, grey n. boitnott, russell t. ewy “effective stress laws for petrophysical rock properties”. spawla 9 th annual logging symposium, may 25-28 2008. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.19 no.3 (september 2018) 11 – 17 issn: 1997-4884 corresponding authors: hayder abdulkareem aljandeel, email: haider.aljendeel@yahoo.co.uk, hussein qasim hussein, email: husseinqassab@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. kinetic study of hydroisomerization of n-decane using pt/sapo11 catalysts hayder abdulkareem aljandeel and hussein qasim hussein chemical engineering department, university of baghdad, baghdad, iraq abstract the hydroisomerization of n-decane was studied on sapo-11 catalyst. catalyst of 0.25wt.%pt/sapo-11 was prepared locally and used in the present work. the hydroconversion performed in a continuous fixed-bed laboratory reaction unit. experiments of ndecane isomerization were performed in a temperature range of 200 to 275°c,lhsv range of 0.5-2 h -1 , and hydrogen to decane mole ratio of 2.1-8.2. the results show that the n-decane conversion increases with increasing temperature and decreasing lhsv , the maximum conversion 56.77 % was achieved at temperature 275°c and lhsv of 0.5 h -1 . the kinetic of n-decane isomerization was also studied and the reaction was first order. the kinetic analysis also showed that the activation energy equal to 61.1137 kj/mol. keywords: sapo-11 catalyst, isomerization, n-decane received on 24/06/2018, accepted on 11/07/2018, published on 30l09l2018 https://doi.org/10.31699/ijcpe.2018.3.2 1introduction isomerization, cracking and alkylation are acidcatalyzed reactions. considering the great amount of oil consumption in the world, it can be concluded that acid catalyzed reactions of hydrocarbon are critically important and not surprisingly that many studies have been published for this reason. nonetheless, important questions regarding the mechanism and the effect of the catalyst pore structure on the activity and selectivity remain to be answered ‎[1]. regardless the reaction involved in a particular process, it is of considerable importance that the catalyst exhibits not only the ability to perform its specific functions initially but also perform them satisfactorily for sufficient periods of time. the analytical terms used to measure the efficiency of a particular catalyst performance in a particular hydrocarbon conversion process are activity, selectivity and stability ‎[2]. isomerization of n-paraffins to branched isomers is important in petroleum refining industry for improving fuels properties such as high gasoline octane number ‎[3] and diesel fuel with high cetane number, low pour point and high viscosity index. to accomplish high isomerization selectivity, balance between metal and acid functions is needed ‎[4]. in the hydroisomerization process, catalytic systems have been successfully constructed for hydroisomerization evolution ‎[5]. these systems employ bifunctional catalysts that contain noble metal particles as hydrogenation/dehydrogenation components in association with an acidic component. recently, among the several catalytic materials investigated for n-alkane isomerization, zeolite with large pores has been reported to produce a large yield of cracked products. this could be due to their spatial constraints that might induce shape selectivity or excessive acid sites that would induce cracking. on the other hand ‎[6], sapo-11 with one-dimensional 10-membered ring channels has attracted the attention in the field of hydroisomerization due to its shape selectivity and moderate acidity ‎[7]. sapo-11 showed perfect conversion of hydrocarbons into isomers ‎[8],‎[9]. however, the microporous structure of sapo-11 stops multi-branched isomers formation. it is generally observed that the active sites for isomerization are located near the pore mouths of the sapo-11 ‎[10]. therefore, for satisfy the mono-branched isomers production from long chain paraffins it is important to investigate sapo-11 with suitable pore structure ‎[11]. for good performance, suitable catalyst is needed for the conversion of hydrocarbons. many catalysts were used in the isomerization of long chain nalkanes, however, sapo-11 was found to be the most efficient catalyst in the isomerization of long chain alkanes and this is due to its medium acidities and appropriate pore structure (one dimensional 10membered-ring channel of 0.39 nm x 0.63 nm) and ael pore structure ‎[12]. the present study aimed to synthesis pt/sapo-11 by impregnation method, then pysico-chemical properties were compared. n-decane was used to study the catalytic activity of pt/sapo-11for isomerization process and study the effect of pyridine adsorption on bronsted and lewis acid site of sapo-11 catalysts. https://doi.org/10.31699/ijcpe.2018.3.2 h. a. aljandeel and h. q. hussein / iraqi journal of chemical and petroleum engineering91,3(8192) 11-17 21 2experimental work 2.1. material and method a. chemicals n-decane 99% ( bdh, england) is used as feed stock in this study. ortho phosphorous acid (85 wt% h3po4) (panreac, spain); aluminum isopropoxide (bdh, england); di-n-propylamine, m.wt. 101.19 (bdh, england) as template. silica sol. 99.9% (qingdaw jiyida, china); deionized water; poly vinyl alcohol (pva) 99% (sigma) as a binder; ɤ-nano-alumina.99.99% (hwnano,china) are used to synthesized sapo-11. hexachloroplatinic acid (40wt%pt), m.wt. 517.92 (fluk chemi ag) b. synthesis of sapo-11 sapo-11 was prepared by adding 46.1 g of phosphorous acid as a source of phosphor and 167.2 g of water (double the amount used in the literature‎[8] ) were added to the gelation mixture at a temperature of 30°c, these contents were mixed until a homogeneous mixture was obtained. after 30 minutes of stirring, 81.7 g of aluminum isopropoxide was added and stirred for 2 hours. a structure-directing template of 14.7 g of di-npropylamine was added into the gelation autoclave, this is followed by immediate addition of 13.85 g of silica sol. the reaction mixture was prepared by stirring part of this mixture for 2 hours. the mixture was aged at room temperature for 24 hours without stirring and then was crystallized in a stainless steel crystallization autoclave at temperatures of (170,180,190 and 200) °c for 24 hour . following the filtration of the crystallized products, they were washed and dried at 110°c for 3 hours. raw powders were then calcined in furnaces at 550°c for 3 hours and then cooled afterwards. the molecular sieve was then obtained in a powder form. the molar composition of molecular sieve after calcination is al2o3:0.93p2o5:0.414sio ‎[13]. c. synthesis of pt/sapo-11 pt/sapo-11 was prepared using impregnation method. a sapo-11 catalyst was dried at 110°c in a furnace in two hours. the impregnation needs hexchlorplatinic acid solution containing 0.368 g of h2ptcl6 with deionized water till the volume of solution equal to pore volume of sapo-11. then the catalysts was dried at 110°c overnight and the calcinated at 300°c in a furnace for 3 hours ‎[14]. d. sapo-11 characterization  x-ray diffraction (xrd) the purity of the prepared sapo-11 was examined after comparison between 2ɵ and d-spacing of the prepared samples with 2ɵ and d-spacing which are synthesized by zhang et al ‎[17]. the prepared sample was tested using x-ray diffractometer shimadzu srd 6000, japan, with cu wave length radiation 1.54060 cm -1 in the 2 theta ranges from 5-60°, and fixed power source 40kv, 30ma. xrd for prepared samples was performed at the ministry of science and technology.  x-ray florescence (xrf) the percentage of oxides was tested using x-ray fluorescence (spectro xeros, ametek, germany) germany. xrf sample was performed at university of baghdad/college of science/ department of geology.  afm the atomic force microscopy (afm) method was used to find the average particle size of the prepared catalyst. it was tested at the department of chemistry/ college of science/ university of baghdad using atomic force microscope device (type angstrom, scanning probe microscope, advanced inc, aa 3000, usa).  bet surface area and pore volume specific surface area was determined by the brunaueremmett-teller method using 0.01 as the value of maximum relative and pore volume was performed using a micrometrics asap 2020. the samples were disarmament of gas for 2 hr under vacuum at 250°c. surface area and pore volume samples were performed at prdc laboratory, ministry of oil /iraq.  fourier –transform infrared spectroscopy (ftir) this test was applied using (iraffinity,shimazdo,japan) with wave range between (4004000)cm -1 at ibn-sina state company / ministry of industry and minerals. e. isomerization process reactor was charged with 44.4 cubic centimeters of fresh catalyst which insert between two layers of glass balls as inert materials. then hydrogen was flow at 350 º c for 3hours in the reactor to reduce the catalysts ‎[15]. after that the air was expelled from the reactor using nitrogen gas, meanwhile, the reactor is heated to the desired temperature. after reaching the reaction temperature, the nitrogen valve was closed. n-decane feed was heated first then enter to evaporator to be vaporized then it was mixed with hydrogen and entered from the top of the reactor, distributed uniformly and reacted on the catalyst inside the reactor. the product gases passed through the condenser and the condensate was collected. pt/sapo-11 catalysts were used for kinetic study of the isomerization reaction. h. a. aljandeel and h. q. hussein / iraqi journal of chemical and petroleum engineering91,3(8192) 11-17 21 the conditions employed are temperatures of (200-275) ºc, liquid hourly space velocity of 0.5-2hr -1 , hydrogen to n-decane mole ratio of 2.1-8.2 and finally the pressure was kept atmospheric. f. test of isomerization gas chromotograph (gc) the reaction product analysis was obtained at ibn-sina state company/ ministry of industry and minerals using a chromatographic analysis on packed model 438aavsa. g. reaction unit the experiments were carried out in a continuous laboratory scale unit. fig. 1 show the process flow diagram.the unit consists of feed drum, gas flow meters, feed pump, evaporator, reactor, separator, collector and cooler with appropriate control system for heating. fig. 1 the catalytic hydro-conversion unit process flow digrame 3results and discussion 3.1. x-ray diffraction the purity of sapo-11 which prepared was tested after a comparison between 2ɵ and d-spacing of the prepared samples with 2ɵ and d-spacing which are synthesized by zhang et al., ‎[17]. fig. 2 shows the x-ray diffraction patterns of sapo-11 sample. the sample was hydrothermally crystallized at 190 °c. table 1. comparison of lattice spacing and angle, between prepared sapo-11 catalyst (190°c crystallization temperature, aging and double water contents) and standard sapo-11 ‎[16]. synthesis sapo-11 catalyst standard sapo-11catalyst angle(2theta) deg. d, spacing(å) angle(2theta) deg. d, spacing(å) 8.127 10.87 8.08 10.93 9.778 9.04 9.30 9.30 13.236 6.683 13.09 6.76 13.861 6.383 13.79 6.42 15.573 5.686 15.76 5.62 20.238 4.384 20.29 4.372 21.26 4.174 21.22 4.183 22.48 3.9513 22.24 3.994 23.00 3.951 22.89 3.881 23.39 3.800 23.31 3.813 24.80 3.58 24.48 3.364 25.12 3.514 24.99 3.560 26.67 3.339 26.46 3.366 28.782 3.099 28.90 3.087 29.641 3.011 29.56 3.020 fig. 2. x-ray diffraction of sapo-11 3.2. x-ray florescence the molar composition of sapo-11 after calcination is 1al2o3:0.93p2o5:0.414sio2 3.3. particle size of sapo-11 catalyst the atomic force microscopy (afm) method was used to find the average particle size, the average particle diameter reaches 57.39 nm for the synthesized catalysts. 3.4. surface area and pore volume sapo-11 displays larger surface area and pore volume 396.17 m 2 g -1 and 0.3159 cm 3 g -1 respectively at a temperature 190°c with aging for 24 hr. these values (surface area and pore volume) in this research are higher than previous work ‎[17]. h. a. aljandeel and h. q. hussein / iraqi journal of chemical and petroleum engineering91,3(8192) 11-17 21 the decline in particle size of zeolite crystals from the micro-level to nano-level resulted in considerable rise in surface area, thus yielding more active sites. 3.5. fourier infrared spectroscopy ftir a sapo-11 catalyst was analyzed using ft-ir spectroscopy to study the structure and the chemical bonds between molecules. ft-ir spectra measured the intensity of the lattice vibration in the range 4000 to 500 cm -1 by using a spectrometer for the adsorption of kbr studies. ftir was used to investigate the nature and quantum of hydroxyl groups produced by si. the spectra of the catalyst sample in the oh stretching are shown in fig. 3 sapo-11 sample has three bands at 3743, 3677 and 3625 cm -1 , the former two bands refer to si-oh, p-oh groups respectively. the third one represents the spectra of the prepared brønsted acid site and the bridge si-oh-al that describes the acid properties of the sample ‎[18]. the band 1100 cm -1 attributed to the asymmetric stretch of o–p–o; 730 cm -1 arising from the symmetric stretch of o–p–o; 640 cm -1 due to the bend of double 6-ring; 575 cm -1 , 530 cm -1 and 480 cm -1 ascribed to the bend of po4, alo4, and sio4, respectively. fig. 3. ft-ir of synthesized sapo-11 3.6. pyridine ftir ft-ir spectroscopy is a technique which is used for intensifying of brønsted and lewis acid sites by adsorption of pyridine on the catalysts ‎[19]. the ft-ir spectra of pyridine adsorbed on sapo-11 , and pt/sapo11 are shown in fig. 4 and fig. 5. the intensity of the bands at 1550 and 1450 cm -1 were believed to be proportional to brønsted and lewis acid sites concentrations, respectively. it is clear from these figures that all the samples gave broad vibrational bands at 1455 cm ‒1 and 1545 cm ‒1 , from pyridine molecules adsorbed on lewis (l) and brönsted (b) acid sites, respectively ‎[20]. the band at 1490 cm ‒1 corresponds to pyridine molecules adsorbed on both l and b acid sites ‎[19]. the absorbance peaks for pyridine molecules adsorbed on the l or b acid sites changed after the introduction of platinum , for all samples, its contain medium acidic sites indicating that the acid sites were only slightly affected by the metal component. because of the low content of the metal component, the addition of pt had small influence on the acidity of the catalysts. this is in agreement with chen et al ‎[19] and zhang et al ‎[20]. fig. 4. ft-ir of synthesized sapo-11with adsorption of pyridine fig. 5. ft-ir of synthesized pt/sapo-11 with adsorbed pyridine 3.7. isomerization of n-decane the activity of pt/sapo-11 was tested for isomerization of n-decane at different temperatures (200-275°) and lhsv (0.5-2 hr -1 ). a. effect of temperature fig. 6 shows the effect of temperature on isomerization process, it is clearly shown from this figure that increasing the temperature leads to increases the conversion of n-decane at constant lhsv and this is due to the nature of isomerization reaction which is endothermic while the change of the chain from n-alkanes to iso-alkanes is exothermic and this is in agreement with alhassani ‎[21]. as an example, the conversion of n-decane using lhsv of 0.5 hr -1 on pt/sapo-11 increases from 40.32 % at 200 º c to 56.77% at 275 º c. h. a. aljandeel and h. q. hussein / iraqi journal of chemical and petroleum engineering91,3(8192) 11-17 21 fig. 6. conversion of n-decane at different temperature and lhsv on pt/sapo-11. b. effect of lhsv fig. 7 show the changes of n-decane conversion as a function of contact time which is expressed by lhsv. as lhsv decreases the conversion increases. this means that increasing the residence time leads to increase the contact time of the feed with the catalyst inside the reactor. all results indicate that low lhsv is favored for an isomerization process as long as higher space velocities conversions are lower, unless the temperature is raised ‎[9]. fig. 7. conversion of n-decane at different contact time on pt/sapo-11 c. kinetic study in catalytic systems and based on the weight of catalyst pellets, the rate equation can be expressed in the following form:    ax a a a r dx f w 00 (1) differentiation equation 1 yields: )( 0a a a f w d dx r  (2) according to the differential method, the rate of reaction can be estimated by finding the slopes of the line tangent to the curve which represents the relationship between n-decane conversion and         ao f w at any given point. figure 8 show the plots of %conversion vs. the         ao f w . fig. 8. experimental value of conversion of n-decane vs w/fao on pt/sapo-11 at different temperature d. the reaction order with respect to n-decane the reaction is a first order reaction due to the linear relationship between -raand ca as shown in fig. 9. no significant changes in the reaction order were detected when the temperature increases from 200-275ºc. the reaction rate constants (k) were calculated at different reaction temperatures according to the linear relation between –ra and ca. table 2 shows the values of rate constants that were obtained at different reaction temperatures. fig. 9. relation between ra and ca for pt/sapo-11 table 2. values of rate constant at different reaction temperatures reaction temperature (°c) k (liters /hr.kg catalyst) pt/sapo-11 200 14.78 225 35.233 250 72.04 275 122.80 e. the apparent activation energy measurements the activation energy of isomerization reaction was calculated using arrhenius equation, which relates the rate constant with the reaction temperature. 0 10 20 30 40 50 60 150 170 190 210 230 250 270 290 temperature °c c o n v e rs io n % lhsv=0.5 lhsv=1 lhsv=1.5 lhsv=2 0 10 20 30 40 50 60 0 0.5 1 1.5 2 2.5 lhsv (hr -1 ) % c o n v e rs io n 200°c 225°c 250°c 270°c 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0 200 400 600 800 1000 1200 w/fa0 (g cat .s/mmol) c o n v e rs io n 200°c 225°c 250°c 275°c 0 75 150 225 300 375 450 525 2 2.2 2.4 2.6 2.8 3 3.2 3.4 3.6 3.8 4 ca(mole/liter) -r a ( m o le /h r .k g c a t) 200°c 225°c 250°c 275°c h. a. aljandeel and h. q. hussein / iraqi journal of chemical and petroleum engineering91,3(8192) 11-17 21 rt ea aek   (3) the plot of (ln k) vs. (1/t) shown in fig. 10were used for the calculation of the activation energy for the isomerization reaction and it was equal to 61.1137 kj/mol. fig. 10. arrhenius plots for isomerization process of ndecane on pt/sapo-11 4conclusion sapo-11 catalyst was prepared experimentally and subjected to many tests (xdr,xrf,afm,bet and pyridine adsorption) that showed its relevance for using in isomerization reaction. n-decane was used in isomerization reaction, n-decane conversion increases as the temperature is increasing from 200 to 275°c and decreases as the lhsv is increasing from 0.5 to 2 hr -1 . the highest n-decane conversion over pt/sapo-11 56.77% was achieved at 275°c and 0.5 hr -1 lhsv, while the reaction order was first order. also, the catalysts gave a high activity in isomerization process, and no cracked product produced in this range of operating conditions. references [1] gauw f.j.m., grandell j., santen r.a.,"the intrinsic kinetics of n-hexane isomerization catalyzed by pt loaded solid acid catalyst", j. catal. 206, 2002, 295304. [2] hilfman lee, "hydroprocessing of hydrocarbons over nickel, molybdenum, and platinum catalyst", us patent, 4175033, 1979. [3] exner h., nagy e., fetting f., gubicza l.,"kinetic of hydroisomerization of n-alkane on nickel zeolite", proc. of 5 th conference of applied chemistry unit operation process, vol.2, 1989, 420-425. [4] song x., bai x., wu w., kikhtyanin o.v., zhao a., xiao l., su x., zhang j., wei x., "the effect of palladium on the catalytic performance of pd/sapo11 for n-decane hydroisomerization"., molecular catalysis, 433,2017,84-90. [5] bokhoven j.a., tramp m., koningsbarger j.t., miller and pieters j.a.z., lercher j.a., williams, kung,"an explanation for enhanced activity for light alkane conversion in mildy steam dealuminated mordenite", j. catal. 202, 2001, 129-140 . [6] rabo j.a. and gajda,, "development of kinetic model of reforming reaction on zeolite", j. catal. kev. sci. eng., 31, 385, 1989. [7] lawrence tucker kass, "isomerization process with improved chloride recovery", united states patent 5705730, 1998. [8] zhipeng m., liu z., song h., bai p., xing w., yan z., zhao l., zhang z.,and gao x., " synthesis of hierarchical sapo-11 for hydroisomerization reaction in refinery processes", appl petrochem.res ,vol 4 (2014),351-358. [9] cui x.,liu y. and liu x., "controlling acidic sites to improve hydroisomerization performance of pt/sapo-11 catalysts", catal lett, 145(2015), 14641473. [10] sastre g., chica a., and corma a. "on the mechanism of alkane isomerization (isodewaxing) with unidirectional 10member ring zeolites. a molecular dynamics and catalytic study", journal of catalysis 195, 2000, 227-236. [11] sinha a. k. , sivasanker s. , and ratnasamy p., " hydroisomerization of n-alkanes over pt-sapo-11 and pt-sapo-31 synthesized from aqueous and nonaqueous media", ind. eng. chem. res. 37,1998, 2208-2214. [12] shengzhen zhang, sheng-li chen peng dong, zhiyong ji, junying zhao, and keqi xu , "synthesis, characterization and hydroisomerization catalytic performance of nanosize sapo-11 molecular sieves" , catalysis letters, vol. 118,2007, p. 109-117. [13] hussein q. h. and aljandeel h.a.," studying influence of aging and crystallization temperature on characteristics of sapo-11 catalyst using hydrothermal method", 1 st international conference on recent trends of engineering sciences and sustainability, 2017. [14] masologites., george, "method of treating a used pt group alumina catalyst with a metal promoter", us patent, 4070306, 1987. [15] chang c.d. , princeton n.j., jose g., sontiesteban, david l., stern, "isomerization process", us patent, 6080904, 2000. [16] american, n. s., 1979. standard specifications and operating instructions for glass capillary kinematic viscomrters. d446-74, deutsche norm din 366 und 51372. [17] zhang f., liu y., shu x., wang w. and qin f. , " sapo-11 molecular sieve, its synthetic method and a catalyst containing the molecular sieve", us patent, 6596156, 2003. [18] meriaudeau p.,tuan v.a., hung l.n., lefebvre f., and nguyen h.p., "zirconium-sapo-11, the peculiar effect of zirconium addition on the catalytic properties for n-butene isomerization", j. chem. soc., faraday trans., 1997, v ol. 93 . 0 1 2 3 4 5 6 0.0018 0.00185 0.0019 0.00195 0.002 0.00205 0.0021 0.00215 1/t(k -1 ) ln (k ) pt/sapo-11 https://www.sciencedirect.com/science/article/pii/s0021951701934797 https://www.sciencedirect.com/science/article/pii/s0021951701934797 https://www.sciencedirect.com/science/article/pii/s0021951701934797 https://www.sciencedirect.com/science/article/pii/s0021951701934797 https://patents.google.com/patent/us4175033a/en https://patents.google.com/patent/us4175033a/en https://patents.google.com/patent/us4175033a/en https://www.sciencedirect.com/science/article/pii/s1381116916305775 https://www.sciencedirect.com/science/article/pii/s1381116916305775 https://www.sciencedirect.com/science/article/pii/s1381116916305775 https://www.sciencedirect.com/science/article/pii/s1381116916305775 https://www.sciencedirect.com/science/article/pii/s1381116916305775 https://dspace.library.uu.nl/handle/1874/5844 https://dspace.library.uu.nl/handle/1874/5844 https://dspace.library.uu.nl/handle/1874/5844 https://dspace.library.uu.nl/handle/1874/5844 https://dspace.library.uu.nl/handle/1874/5844 https://patents.google.com/patent/us5705730a/en https://patents.google.com/patent/us5705730a/en https://patents.google.com/patent/us5705730a/en https://link.springer.com/article/10.1007/s13203-014-0071-0 https://link.springer.com/article/10.1007/s13203-014-0071-0 https://link.springer.com/article/10.1007/s13203-014-0071-0 https://link.springer.com/article/10.1007/s13203-014-0071-0 https://link.springer.com/article/10.1007/s13203-014-0071-0 https://link.springer.com/article/10.1007/s10562-015-1554-z https://link.springer.com/article/10.1007/s10562-015-1554-z https://link.springer.com/article/10.1007/s10562-015-1554-z https://link.springer.com/article/10.1007/s10562-015-1554-z https://www.sciencedirect.com/science/article/pii/s0021951700930021 https://www.sciencedirect.com/science/article/pii/s0021951700930021 https://www.sciencedirect.com/science/article/pii/s0021951700930021 https://www.sciencedirect.com/science/article/pii/s0021951700930021 https://www.sciencedirect.com/science/article/pii/s0021951700930021 https://pubs.acs.org/doi/abs/10.1021/ie9707228 https://pubs.acs.org/doi/abs/10.1021/ie9707228 https://pubs.acs.org/doi/abs/10.1021/ie9707228 https://pubs.acs.org/doi/abs/10.1021/ie9707228 https://pubs.acs.org/doi/abs/10.1021/ie9707228 https://link.springer.com/article/10.1007/s10562-007-9138-1 https://link.springer.com/article/10.1007/s10562-007-9138-1 https://link.springer.com/article/10.1007/s10562-007-9138-1 https://link.springer.com/article/10.1007/s10562-007-9138-1 https://link.springer.com/article/10.1007/s10562-007-9138-1 https://link.springer.com/article/10.1007/s10562-007-9138-1 https://link.springer.com/article/10.1007/s10562-007-9138-1 https://link.springer.com/article/10.1007/s10562-007-9138-1 https://patents.google.com/patent/us6596156b1/en https://patents.google.com/patent/us6596156b1/en https://patents.google.com/patent/us6596156b1/en https://patents.google.com/patent/us6596156b1/en http://pubs.rsc.org/en/content/articlehtml/1997/ft/a704861k http://pubs.rsc.org/en/content/articlehtml/1997/ft/a704861k http://pubs.rsc.org/en/content/articlehtml/1997/ft/a704861k http://pubs.rsc.org/en/content/articlehtml/1997/ft/a704861k http://pubs.rsc.org/en/content/articlehtml/1997/ft/a704861k h. a. aljandeel and h. q. hussein / iraqi journal of chemical and petroleum engineering91,3(8192) 11-17 21 [19] chen w., hui-hsin ko, ayyamperumal sakthival, shing-jong huang, shou-heng liu,an-ya lo, tesengvhang tsai, shang-bin liu, " a solid state nmr,ft-ir and tpd study on acid properties of sulfated and metal-promoter and sulfation treatment" , catalysis today, 116(2006), 111-120. [20] zhang s., chen s., dong p.,ji z.,zhao j. and xu k., "synthesis, characterization and hydroisomerization catalytic performance of nanosize sapo-11 molecular sieves" , catalysis letters, vol. 118, p. 109-117, 2007. [21] al-hassany m., " effect zro2 , wo3 additives on catalytic performance of pt/hy zeolite compared with pt/γ-al2o3 for iraqi naphtha transformation", journal of enginnering, vol. 15, number 4,2009,43784394 . دراسة حركية تفاعل االزمرة الهايذروجينية للذيكان االعيتادي باستخذام العامل المساعذ pt/sapo-11 الخالصة حٌث تم تحضٌر sapo-11تمت دراسة عملٌة االزمرة الهاٌدروجٌنٌة للدٌكان االعتٌادي على محفز 0.25% pt/sapo-11 ًٌا واستخدامه فً العمل الحالً. ٌتم إجراء عملٌة االزمرة فً منظومة رٌادٌة محل 200تحتوي على مفاعل ذو الحشوات الثابتة. ان تجارب ازمرة الدٌكان تمت بدرجات حرارة تراوحت من سا 2-0,5من سرع فراغٌة تراوحت من م ، و ° 275إلى -1 ٌادي ، والهٌدروجٌن إلى نسبة الدٌكان االعت سا 0,5م وسرعة فراغٌة °275% فً درجة حرارة 57,77.ان اعلى نسبة تحول هً 2.2إلى 2.1من -1 . كذلك تمت دراسة حركٌة ازمرة الدٌكان وبٌنت النتائج ان تحول الدٌكان االعتٌدادي ٌزداد مع زٌادة درجة لك ان التحلٌل الحركً ٌبٌن ان الطاقة الحرارة وتقلٌل السرعة الفراغٌة. ان التفاعل هو من الدرجة االولى. كذ كجول/مول.71,1137المنشطة تساوي https://www.sciencedirect.com/science/article/pii/s0920586106002021 https://www.sciencedirect.com/science/article/pii/s0920586106002021 https://www.sciencedirect.com/science/article/pii/s0920586106002021 https://www.sciencedirect.com/science/article/pii/s0920586106002021 https://www.sciencedirect.com/science/article/pii/s0920586106002021 https://www.sciencedirect.com/science/article/pii/s0920586106002021 https://link.springer.com/article/10.1007/s10562-007-9138-1 https://link.springer.com/article/10.1007/s10562-007-9138-1 https://link.springer.com/article/10.1007/s10562-007-9138-1 https://link.springer.com/article/10.1007/s10562-007-9138-1 https://link.springer.com/article/10.1007/s10562-007-9138-1 https://www.iasj.net/iasj?func=article&aid=24393 https://www.iasj.net/iasj?func=article&aid=24393 https://www.iasj.net/iasj?func=article&aid=24393 https://www.iasj.net/iasj?func=article&aid=24393 https://www.iasj.net/iasj?func=article&aid=24393 available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.21 no.4 (december 2020) 1 – 9 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: husna salim wahab, email: husna.salim147@gmail.com, name: sawsan a.m. mohammed, email: sawsan.abd@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. removal of acetaminophen residues from wastewater by bulk liquid membrane process husna salim wahab and sawsan a.m. mohammed department of chemical engineering, college of engineering, university of baghdad, baghdad, iraq abstract the removal of anit-inflammatory drugs, namely; acetaminophen (actp), from wastewater by bulk liquid membrane (blm) process using aliquat 336 (qcl) as a carrier was investigated. the effects of several parameters on the extraction efficiency were studied in this research, such as the initial feed phase concentration (10-50) ppm of actp, stripping phase (nacl) concentration (0.3,0.5,0.7 m), temperature (30-50 o c), the volume ratio of feed phase to membrane phase (200-400ml/80ml), agitation speed of the feed phase (75-125 rpm), membrane stirring speed (0, 100, 150 rpm), carrier concentration (1, 5, 9 wt%), the ph of feed (2, 4, 6, 8, 10), and solvent type (ccl4 and n-heptane). the study shows that high extraction efficiency for actp of about 97% was achieved by a bulk liquid membrane at 50 ppm initial concentration of feed; stirring speed of feed phase 130 rpm; stirring speed of membrane phase 100rpm; 0.5 m nacl concentration; carrier concentration 1wt%; volume ratio of 200ml feed:80ml membrane; feed ph of actp is 6, and 50˚c. the transport kinetics was evaluated using a kinetic model with two consecutive first-order irreversible reactions. the kinetics of (actp) transport by bulk liquid membrane was investigated at the best experimental conditions. the activation energy values of the extraction and stripping processes were 1.733 and 1.826 kj.mol −1 . the activation energy confirms that the transport process from solutions is controlled by diffusion. keywords: anti-inflammatory drugs, acetamionphen (actp), bulk liquid membrane, wastewater treatment, aliquat 336. received on 12/07/2020, accepted on 05/09/2020, published on 30/12/2020 https://doi.org/10.31699/ijcpe.2020.4.1 1introduction the chronic toxicity of pharmaceuticals present to nature and human beings in the aquatic environment has recently become extremely concerning. the use of prescription medications, or over the counter medicines, is measured at thousands of kilograms a year worldwide. such compounds may be discharged as metabolites or in unchanged form into the water, then deposited in the aquatic ecosystem, and can contaminate aquifers and underground water. acetaminophen (actp) is a commonly used drug in the group of anti-inflammatory non-steroidal medicines. these are commonly used to treat menstrual pain, inflammation, fever, rheumatoid arthritis, and migraines. the active substance of pharmaceuticals is among the most important pollutants on the who list [1]. the potential influence on human health and environmental impact of acetaminophen is identified to occur at high concentrations of a microgram per liter and is eliminated effectively by wastewater treatment plants (wwtps) for the most part. it was found in european wastewater effluents to have a concentration of up to 6 μgl −1 , in us natural waters up to 10 μgl −1 , and in tyne river, the uk over 65 μgl −1 [2]. the maximum concentration for acetaminophen in one of the iraqi cities (basra) was found to be 23.99 μg l −1 [3]. different techniques have been used for the recovery or removal of organic compounds contained in wastewater, such as coagulation, activated carbon adsorption, electrochemical methods, uv irradiation, volatilization, sedimentation and filtration, photocatalysis, or fenton oxidation. such processes, however, are of limited efficiency and significant concentrations persist in treated waters [4]. recently, bulk liquid membrane (blm) has gained significant attention and has proven to be an efficient extraction method for pollutants removal from wastewater, as well as being an effective method for concentrating, isolation and regeneration. liquid membranes are also of considerable significance from an environmental engineering perspective when understanding the transport mechanisms principle [5]. there is no documented work on extracting actp from contaminated water through blm to the best of our knowledge. so a protocol for the recovery of acetaminophen from aqueous solutions was developed using blm. the parameters to achieve high efficiency of actp removal by bulk liquid membranes (blm) were evaluated. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:husna.salim147@gmail.com mailto:sawsan.abd@coeng.uobaghdad.edu.iq.org http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2020.4.1 h. s. wahab and s. a.m. mohammed / iraqi journal of chemical and petroleum engineering 21,4 (2020) 1 9 2 2experimental work the solutions of membrane phase were prepared by dissolving the carrier aliquat 336 (kunshan yalong trading co. ltd, china) in carbon tetrachloride (bdh chemicals ltd poole). dissolved actp (sigma-aldrich) was used as a feed phase in water. the actp's molecular structure is shown in fig. 1 sodium chloride (avon chem. ltd, uk) in deionized water was used to prepare the strip phase solution. fig. 1. acetaminophen (actp) chemical structure the experiments were performed using a borosilicate glass cell with dimensions of 12cm length, 6 cm width, and 12 cm height. the cell consists of two equal compartments; a partition wall of a thickness of 0.2 cm was located in the middle of the cell. this wall rises from the bottom by 8 mm to permit the transfer of actp from one section to another. a volume of 80 ml of carbon tetrachloride (ccl4) was measured and transferred to the cell above the bottom clearance. the actp solution of 50 ppm concentration, represents the feed phase, whilst, nacl (0.5 m) solution represents the stripping phase. the volume of the feed phase and stripping phase was 200 ml. fig. 2 shows the schematic diagram of the cell used. to examine the temperature effect on the extraction efficiency of the actp, the experiments were carried out at 30, 40, and 50 ºc in a similar stainless steel cell. the feed and stripping phases were agitated using mechanical stirrers (heidloph rzr2021) with stainless steel propeller stirrer; 4-bladed of 3.5 cm diameter, whereas the membrane phase was agitated by magnetic stirrer (labinco l-81) with a magnetic bar. a sample of (1 ml) was taken from the feed phase and stripping phase every 3 minutes. the obtained samples were scanned by uv-vis spectrometer (genesys 10uv) at 287 nm to obtain the extraction efficiency of actp. in the case of stripping solution, the absorbency was recorded for actp-na and converted to actp according to the balanced equations given in sec. 3.1. fig. 2. schematic diagram of the cell used for actp extraction the extraction efficiency is calculated using eq. 1 for estimating the bulk liquid membrane performance [5]. e% = 𝐶𝑜−𝐶𝐹 co × 100 (1) where: e is the efficiency of extraction, c0 is the initial feed phase concentration of actp (ppm), and cf is feed samples concentration at any time of the experiment. 3results and discussions 3.1. mechanism of transfer actp's transfer mechanism from the feed phase to the strip phase, the role of aliquat 336, and the steps of the process are illustrated in fig. 3. in this system, the transfer rate of acetaminophen from the feed to stripping phase was improved by the extractant aliquat 336, and the extractant reacted with actp at interface ι to produce complex. the complex then diffuses across the membrane from the interface i to interface ii. the complex breaks down and the carrier regenerates at interface ii and diffuses back across the membrane. actp ionizes and reacts with na + ions and produces a non-diffusive compound and the carrier can be recovered. the reaction between actp and qcl is given by eqs. (2 and 3) [6]: in the feed section: (r3ch3n + cl )org+(c8h9no2)aq ⇌ (r3ch3n + c8h8no2)+(h + cl )aq (2) in the stripping section: (r3ch3n + c8h8no2)org+(na + cl )aq ⇌ (r3ch3n + cl )org+(c8h8no2na + )aq (3) h. s. wahab and s. a.m. mohammed / iraqi journal of chemical and petroleum engineering 21,4 (2020) 1 9 3 fig. 3. actp transfer mechanism 3.2. factors affecting bulk liquid membrane performance a. the concentration of carrier the important element of blm is the carrier which reacts with the active component from the feed phase by making a complex with it and after successive diffusion into the organic phase; the component is released into the stripping phase. to study the carrier concentration effect on the transport of actp, the experiments were carried out at three different concentrations of the carrier (1, 5, and 9 wt. %) [7]. from fig. 4, it can be seen that there is an increase in the actp extraction efficiency with time which reveals that the system can extract large amounts of actp from dilute solutions. it can be also observed that the transfer of actp was increased with an improvement in the concentration of aliquat 336 (qcl) up to a certain concentration and then decreased. maximum actp transport obtained was at carrier concentration of 5 wt percent. this could be due to the probability of complex formation increases by increasing the concentration of qcl. further experiments were conducted with 9% qcl and it was observed that the extraction efficiency decreased indicating that a further increase in the concentration of qcl will not have a considerable effect on the process. this can be explained due to the slow release of qcl from the complex of actp-qcl. also, the resistance of mass transfer increases because of the viscosity increase in the membrane phase, which causes a reduction in the diffusivity of the actp-qcl complex across the membrane phase. it is always desirable to make the blm less expensive by using a small amount of qcl as long as there are enough carriers to extract actp from an aqueous solution, for which 1wt percent qcl has been chosen for all the extraction experiments. the results are consistent with that obtained by sahoo, et.al [7]. fig. 4. carrier concentration effect on the extraction efficiency of actp (feed phase ph=6; feed concentration=50 ppm; concentration of nacl = 0.5 m; agitation speed of aqueous phase = 130 rpm; agitation speed of membrane phase =100 rpm; temperature=22 ºc) b. feed phase and stripping phase agitation speed fig. 5 shows that increasing the agitation rate of the feed and stripping phases from 75 to 130 rpm results in a significant increase in the efficiency of extraction. higher agitation speed for feed and stripping aqueous phases increases the rate of extraction by providing better mixing and thus reducing the boundary layer thickness between the membrane phase and the aqueous phase without changing its hydrodynamic stability. it can be noticed from the figure that at further increase of agitation speed the extraction efficiency decreased to some extent, due to deformation of the interfaces between the phases, and even drops of the stripping phase were mechanically transferred to the donor phase. the current work is in agreement with the work done by sahoo, et. al [7]. fig. 5. feed phase and stripping phase agitation speed effect on actp extraction efficiency (ph of feed phase =6; feed concentration=50 ppm; qcl=1 wt%; concentration of nacl = 0.5 m; agitation speed of membrane = 100 rpm; temperature=22ºc) h. s. wahab and s. a.m. mohammed / iraqi journal of chemical and petroleum engineering 21,4 (2020) 1 9 4 c. the agitation speed of membrane from fig. 6, it can be concluded that the membrane agitation speed influenced the membrane extraction efficiency but to a lesser extent relative to the effect of increasing the aqueous phase agitation speed. compared with the case of membrane non-agitation conditions, the performance of the bulk liquid membrane described by the extraction efficiency is considerably enhanced by the presence of membrane agitation. however, as the speed of membrane agitation increased from 100 to 150 rpm, this enhancement was lower, as the efficiency of extraction reduced due to the deformation of the interfaces between the phases. this is supported by the works of mohammed and hameed [8]. fig. 6. membrane agitation speed effect on actp extraction efficiency by bulk liquid membrane (ph of feed phase =6; concentration of feed = 50 ppm; qcl=1 wt%; concentration of nacl = 0.5 m; agitation speed of aqueous phase =130 rpm; temperature=22ºc) d. feed concentration the effect of feed concentration on the extraction process was measured at various initial actp concentrations within the 10–50 ppm range. fig. 7 shows the effect of the concentration of feed on the efficiency of extraction. the final efficiency of extraction for actp increases as the concentration of feed was increased from 10 to 50 ppm; this can be due to an increase in driving force. this rapid increase may be explained by the fact that the interaction between actp and qcl was increased with feed concentration, and at a concentration of 50 ppm, qcl becomes saturated and reaches optimum extraction efficiency, while at a higher feed concentration, the carrier becomes fully saturated and could not efficiently transfer the actp from the aqueous feed phase to the organic phase. the results of the current study appear to be consistent with the work of chaouchi and hamdaoui [9]. fig. 7. effect of feed concentration on actp extraction efficiency by bulk liquid membrane (ph of feed phase =6; qcl=1 wt%; concentration of nacl =0.5 m; agitation speed of aqueous phase =130 rpm; agitation speed of membrane phase =100 rpm; temperature=22ºc) e. stripping phase concentration the strength of the stripping phase plays a significant role as it controls the release of the actpqcl complex extractant. fig. 8 shows that the percentage of actp extraction improved as the sodium chloride concentration increased during the stripping process. the complex dissociates at interface ii to produce free actp, which combines with nacl to give the sodium salt of actp. in the membrane phase, the salt is insoluble and results in the prevention of actp back diffusion, thereby allowing the unidirectional transfer of actp from feed solution to strip solution. this is supported by the works of lakshmi, et al. [10], ng, et al. [11], li, et al.[12], and husna and sawsan [13]. an additional increase in nacl concentration reduced the efficiency to some extent, as higher strip phase concentration provided high solution strength resulted in lower chloride ion activity coefficient to decompose the actp-qcl complex fig. 8. stripping concentrations effect on actp extraction efficiency by bulk liquid membrane (feed phase ph =6; feed concentration= 50 ppm; qcl=1 wt%; agitation speed of aqueous phase =130 rpm; agitation speed of membrane phase=100 rpm; temperature=22 ºc) h. s. wahab and s. a.m. mohammed / iraqi journal of chemical and petroleum engineering 21,4 (2020) 1 9 5 f. feed phase ph fig. 9 demonstrates that the ccl4 bulk liquid membrane extraction efficiency of actp remains almost constant when the feed phase ph is below the acid dissociation constant (pka) value (9.5). however, the extraction efficiency was drastically reduced when the ph of the feed solution approached the pka value or became greater than the pka value. it can be seen from fig. 9 that the removal efficiency of actp remains approximately constant at about 95% when the feed phase ph is held below 6 and becomes 67 and 52 % at ph equals 8 and 10 respectively. the current research results appear to agree with that of fan, et al.[14]. the reduction of actp extraction efficiency results from the fact that actp is a weak acid, and the molecules of qcl cannot solvate the non-charged form of acetaminophen under high ph conditions (≥ pka value). in the alkaline feed phase, because actp is an acidic substance, it converts to the ionic form, and as a result, the solubility of it in the membrane phase decreases, and therefore more actp remains in the feed phase. fig. 9. feed phase ph effect on actp extraction efficiency by bulk liquid membrane (concentration of feed = 50 ppm; qcl=1 wt%; agitation speed of aqueous phase =130 rpm; agitation speed of membrane phase = 100 rpm; temperature=22ºc) g. feed solution to membrane phase volume ratio the volume ratio of the membrane-phase feed solution controls mass transfer through the interface and plays an important role in deciding the performance of blms. the effect on extraction efficiency of the volume ratio of the feed solution to the membrane phase was investigated using two ranges, namely; 200 ml: 80 ml– 400 ml: 80 ml, and the results obtained are given in fig. 10 the figure shows that as the phase volume ratio increases from 200 ml feed: 80 ml ccl4 to 400 ml feed: 80 ml ccl4, the extraction efficiency decreases slightly. this reduction in extraction efficiency could be attributed to the strong solvation ability of ccl4 when used as a solvent in the liquid membrane. a similar observation was made by fan, et al.[14], who extracted phenol from the aqueous solution by [c6mim][pf6] and concluded that the partitioning coefficient of phenol was changed slightly when the volume ratio of feed solution to ionic liquid membrane increased from 1:1 to 5:1. fig. 10. volume ratio of feed solution to membrane phase effect on actp extraction efficiency by bulk liquid membrane (ph of feed phase =6; concentration of feed = 50 ppm; qcl=1 wt%; concentration of nacl = 0.5 m; agitation speed of aqueous phase =100 rpm; agitation speed of membrane phase =100 rpm; temperature=22˚c) h. membrane phase solvent type to select the right membrane solvent for transporting actp, two solvents were investigated, namely: ccl4 and n-heptane. depending on the membrane solvent, the efficiency of the separation, expressed in percentage of the actp transported in the receiving phase is shown in fig. 11. from the figure, it is found that in the case of the ccl4 membrane the best results are obtained. the second solvent provides a low permeability towards the transported actp that is reflected in the removed percentage of actp. fig. 11. the extraction efficiency of actp by two types of bulk liquid membrane (ph of feed phase = 6; concentration of feed =50 ppm; qcl=1 wt%; nacl=0.5m; agitation speed of aqueous phase =130 rpm; agitation speed of membrane phase =100 rpm; temperature=22ºc) h. s. wahab and s. a.m. mohammed / iraqi journal of chemical and petroleum engineering 21,4 (2020) 1 9 6 i. the effect of temperature on the extraction the extraction experiments were carried out at 30, 40, and 50 °c to investigate the influence of temperature on the performance of the actp extraction. figure 12 shows the temperature dependence of the actp extraction efficiency. it can be seen that as the temperature increased, the efficiency was also increased. this increase in efficiency can be explained by increasing the diffusion of the species that transferred through the liquid membrane of ccl4 due to the reduction of the viscosity of the membrane. einstein-stokes eq. (4), relates the diffusion coefficient (d) to viscosity µ, where it is inversely proportional to the viscosity of the liquid, and as a result, the temperature increase causes rising of extraction efficiency which is mainly controlled by diffusion [15]. 𝐷 = 𝑘𝑇 𝑐𝜋µ𝑟 (4) where: d is the diffusion coefficient (cm 2 /s), k is the boltzmann’s constant (erg. k -1 ), t is the absolute temperature (k), c is a constant (4 to 6), µ is liquid viscosity (dyne.cm -2 s -1 ), and r is the stokes radius or effective hydrodynamic in (cm). fig. 12. temperature effect of on actp extraction efficiency by a bulk liquid membrane (ph pf feed phase =6; concentration of feed=50 ppm; concentration of nacl = 0.5 m; agitating speed of aqueous and membrane =100 rpm) 3.3. mathematical model and kinetic parameters the behavior of anti-inflammatory drugs through bulk liquid membranes demonstrated that the pertraction process from a feed phase through an organic membrane into a stripping phase takes place according to a consecutive irreversible first-order chemical reaction according to the kinetic scheme [16]: (5) where: c is the solute concentration in the feed or donor phase (f), liquid membrane (m), and stripping or acceptor (s) phase, k1 and k2 are the first-order rate constants of the apparent membrane extraction and stripping. generally, the reduced concentrations of actp are used to simplify the model equations. (6) (7) then: rf + rm + rs = 1 (8) where: rf, rm, and rs are reduced mole fractions of the actp in the feed (f), liquid membrane (m), and stripping phase (s), respectively. it is evident that rf decreases mono-exponentially over time; the time variation of rs is a monotonically increasing sigmoid type curve, whereas the time variation of rm is the maximum, as shown in fig. (13), at best condition [initial concentration of feed (50 ppm); stirring speed of feed phase (130 rpm); stirring speed of membrane phase (100rpm); nacl concentration (0.5 m); carrier concentration (1wt%); volume ratio (200ml feed:80ml membrane); feed ph of actp is (6), temp. (50˚c)]. fig. 13. actp pertraction experimental results in the bulk liquid membrane: rf: feed phase; rs stripping phase; rm: liquid membrane calculated using the model maximum reduced concentration 𝑅𝑀 𝑚𝑎𝑥 and t max of membrane phase can be found from fig. 13. k1 and k2 can be calculated from the eq. (9,10): 𝑡𝑚𝑎𝑥 = ln⁡( 𝑘2 𝑘1 ) (𝑘2−𝑘1) (9) 𝑘2 = ln( 1 𝑅𝑚 𝑚𝑎𝑥)/𝑡𝑚𝑎𝑥 (10) h. s. wahab and s. a.m. mohammed / iraqi journal of chemical and petroleum engineering 21,4 (2020) 1 9 7 the first-order apparent membrane extraction and stripping rate constants can be used for the determination of the maximum flux (j max ); the steady-state kinetics suggest that throughout the transfer process, the total permeation and exit fluxes between the two phases 𝐽𝐹 𝑚𝑎𝑥 (eq. 11) and 𝐽𝑆 𝑚𝑎𝑥 (eq.12) should be equal in value but with opposite signs, i.e. −⁡𝐽𝐹 𝑚𝑎𝑥 =𝐽𝑆 𝑚𝑎𝑥 [16]. ( 𝑑𝑅𝐹 𝑑𝑡 )|𝑚𝑎𝑥 = −𝑘1 ( 𝑘1 𝑘2 ) −𝑘1 𝑘1−𝑘2 = 𝐽𝐹 𝑚𝑎𝑥 (11) ( 𝑑𝑅𝑆 𝑑𝑡 )|𝑚𝑎𝑥 = 𝑘2 ( 𝑘1 𝑘2 ) −𝑘2 𝑘1−𝑘2 = 𝐽𝑆 𝑚𝑎𝑥 (12) results of kinetic parameters of actp extraction by a bulk liquid membrane at best condition are illustrated in table 1. for any number of reactions taking place in series, it is the slowest step that has the greatest control on the overall reaction rate. the results indicate that k1 is larger than k2, which means that, the rate can be determined by k2, the slowest step in the two-step reaction [16]. table 1. kinetic model parameters for actp pertraction kinetic parameter actp t max ,min 5.8 𝑹𝑴 𝒎𝒂𝒙 0.49876 k1, min -1 0.23798 k2, min -1 0.11994 𝑱𝑭 𝒎𝒂𝒙 , min -1 -0.05978 𝑱𝑺 𝒎𝒂𝒙,⁡min-1 0.0597 the activation energy (ea) of actp extraction and stripping processes can be calculated from the arrhenius equation by using k1 and k2values at various temperatures and plotting (-lnk1 and -lnk2) vs. t −1 [16]: 𝑙𝑛𝑘𝑖 = 𝑙𝑛𝑘𝑜 − 𝐸𝑎 𝑅 (1 𝑇 ) (13) the activation energy values of actp are 1.733 and 1.826 kj mol −1 for extraction and stripping, respectively as shown in fig. 14. fig. 14. arrhenius plot for actp extraction and stripping processes stripping these activation energy values indicate that the transport process for both extraction and stripping is controlled by species diffusion. activation energy values are quite low for diffusion-controlled processes, for which the rate constants are strongly affected by temperature [16]. 4conclusion for extracting actp from acidic aqueous solutions, a blm consisting of ccl4 as solvent, aliquat 336 (qcl) as carrier, and 0.5 m nacl as stripping phase were used. an efficient actp transfer was accomplished for both the feed phase and the stripping phase with a stirring rate of 130 rpm and for the membrane phase 100 rpm. a transfer of almost (95 %) actp to stripping phase was reached after10 minutes. this process can be useful as secondary process during the wastewater treatment. the ph of feed has no effect on the extraction efficiency of actp for ph values less than pka (9.5 ). however, the extraction efficiency was strongly reduced when ph of feed solution ≥ pka. the extraction efficiency of actp decreases slightly when the phase volume ratio increases from 200 ml feed: 80 ml ccl4 to 400 ml feed: 80 ml ccl4. the activation energy values indicate that the transport process for both extraction and stripping is controlled by species diffusion. references [1] s. żółtowska-aksamitowska, p. bartczak, j. zembrzuska, and t. jesionowski, “removal of hazardous non-steroidal anti-inflammatory drugs from aqueous solutions by biosorbent based on chitin and lignin,” sci. total environ., vol. 612, pp. 1223–1233, 2018. [2] v. h. nhat phong, t. koottatep, s. k. chapagain, a. panuvatvanich, c. polprasert, and k. h. ahn, “removal of acetaminophen from wastewater by constructed wetlands with scirpus validus,” environ. eng. res., vol. 21, no. 2, pp. 164–170, jun. 2016. [3] o. s. a. al-khazrajy and a. b. a. boxall, “riskbased prioritization of pharmaceuticals in the natural environment in iraq,” environ. sci. pollut. res., vol. 23, no. 15, pp. 15712–15726, 2016. [4] méndez-arriaga, f., esplugas, s. and giménez, j.,"degradation of the emerging contaminant ibuprofen in water by photo-fenton", water res. 44, pp.589–595, 2010. [5] n. h. yousif and h. m. flayeh, " process optimization study of pb(ii) removal by bulk liquid membrane (blm)" iraqi journal of chemical and petroleum engineering , vol. 21,no. 2, pp. 37-45, 2020. [6] chaouchi, s. and hamdaoui, o. "acetaminophen extraction by emulsion liquid membrane using aliquat 336 as extractant", separation and purification technology. elsevier, 129, pp. 32–40, 2014. doi: 10.1016/j.seppur.2014.03.021 https://www.sciencedirect.com/science/article/abs/pii/s0048969717323793 https://www.sciencedirect.com/science/article/abs/pii/s0048969717323793 https://www.sciencedirect.com/science/article/abs/pii/s0048969717323793 https://www.sciencedirect.com/science/article/abs/pii/s0048969717323793 https://www.sciencedirect.com/science/article/abs/pii/s0048969717323793 https://www.sciencedirect.com/science/article/abs/pii/s0048969717323793 https://www.koreascience.or.kr/article/jako201621650491579.page https://www.koreascience.or.kr/article/jako201621650491579.page https://www.koreascience.or.kr/article/jako201621650491579.page https://www.koreascience.or.kr/article/jako201621650491579.page https://www.koreascience.or.kr/article/jako201621650491579.page https://link.springer.com/article/10.1007/s11356-016-6679-0 https://link.springer.com/article/10.1007/s11356-016-6679-0 https://link.springer.com/article/10.1007/s11356-016-6679-0 https://link.springer.com/article/10.1007/s11356-016-6679-0 https://www.sciencedirect.com/science/article/abs/pii/s0043135409004667 https://www.sciencedirect.com/science/article/abs/pii/s0043135409004667 https://www.sciencedirect.com/science/article/abs/pii/s0043135409004667 https://www.sciencedirect.com/science/article/abs/pii/s0043135409004667 https://doi.org/10.31699/ijcpe.2020.2.5 https://doi.org/10.31699/ijcpe.2020.2.5 https://doi.org/10.31699/ijcpe.2020.2.5 https://doi.org/10.31699/ijcpe.2020.2.5 https://doi.org/10.31699/ijcpe.2020.2.5 https://www.sciencedirect.com/science/article/abs/pii/s138358661400183x https://www.sciencedirect.com/science/article/abs/pii/s138358661400183x https://www.sciencedirect.com/science/article/abs/pii/s138358661400183x https://www.sciencedirect.com/science/article/abs/pii/s138358661400183x https://www.sciencedirect.com/science/article/abs/pii/s138358661400183x h. s. wahab and s. a.m. mohammed / iraqi journal of chemical and petroleum engineering 21,4 (2020) 1 9 8 [7] g. c. sahoo, a. c. ghosh and n. n. dutta "recovery of cephalexin from dilute solution in a bulk liquid membrane" process biochemist., vol. 32, no. 4, pp. 265-272, 1997. [8] mohammed, s. a. m. and hameed, m. s. "extraction of 4-nitrophenol from aqueous solutions using bulk ionic liquid membranes", international journal of current engineering and technology, 66(22), pp. 2277–4106, 2016. [9] attef dâas and oualid hamdaoui "removal of nonsteroidal anti-inflammatory drugs ibuprofen and ketoprofen from water by emulsion liquid membrane" environ sci pollut res (2014) 21:2154–2164 [10] a.brinda lakshmi , s.sindhu , s.venkatesan, "performance of ionic liquid as bulk liquid membrane for chlorophenol removal", pp. 1129–1137, 2013. [11] ng, y. s., jayakumar, n. & hashim, m., "behavior of hydrophobic ionic liquids as liquid membranes on phenol removal:experimental study and optimization", desalination, volume 278, pp. 250– 258, 2011. [12] x. li, s.j. zhan, j.m. zhang, y.h. chen, y.q. zhan, n. sun, "extraction of phenols with hydrophobic ionic liquids", chin. j. proc. eng. 5, pp.148-151, 2005. [13] husna s. w. and sawsan a.m. m., "removal of ibuprofen residues from acidic aqueous solution by bulk liquid membrane", 2nd international conference on materials engineering & science (iconmeas 2019) aip conf. proc. 2213, 020200-1– 020200-9. [14] fan, j. et al., "solvent extraction of selected endocrinedisrupting phenols using ionic liquids", separation and purification technology , volume 61, pp. 324– 331, 2008. [15] hannah c. price, johan mattsson, and benjamin j. murray, “ sucrose diffusion in aqueous solution” , phys. chem. chem. phys., 18, pp.19207-19216, 2016. [16] o. levenspiel, chemical reaction engineering, third edition, john wiley & sons, new york, 1999. https://www.sciencedirect.com/science/article/pii/s0032959296000350 https://www.sciencedirect.com/science/article/pii/s0032959296000350 https://www.sciencedirect.com/science/article/pii/s0032959296000350 https://www.sciencedirect.com/science/article/pii/s0032959296000350 http://inpressco.com/wp-content/uploads/2016/04/paper27542-550.pdf http://inpressco.com/wp-content/uploads/2016/04/paper27542-550.pdf http://inpressco.com/wp-content/uploads/2016/04/paper27542-550.pdf http://inpressco.com/wp-content/uploads/2016/04/paper27542-550.pdf http://inpressco.com/wp-content/uploads/2016/04/paper27542-550.pdf https://link.springer.com/article/10.1007/s11356-013-2140-9 https://link.springer.com/article/10.1007/s11356-013-2140-9 https://link.springer.com/article/10.1007/s11356-013-2140-9 https://link.springer.com/article/10.1007/s11356-013-2140-9 https://www.researchgate.net/profile/venkatesan_sivaramu/publication/286266291_performance_of_ionic_liquid_as_bulk_liquid_membrane_for_chlorophenol_removal/links/5e4e5732299bf1cdb938e36b/performance-of-ionic-liquid-as-bulk-liquid-membrane-for-chlorophenol-removal.pdf https://www.researchgate.net/profile/venkatesan_sivaramu/publication/286266291_performance_of_ionic_liquid_as_bulk_liquid_membrane_for_chlorophenol_removal/links/5e4e5732299bf1cdb938e36b/performance-of-ionic-liquid-as-bulk-liquid-membrane-for-chlorophenol-removal.pdf https://www.researchgate.net/profile/venkatesan_sivaramu/publication/286266291_performance_of_ionic_liquid_as_bulk_liquid_membrane_for_chlorophenol_removal/links/5e4e5732299bf1cdb938e36b/performance-of-ionic-liquid-as-bulk-liquid-membrane-for-chlorophenol-removal.pdf https://www.sciencedirect.com/science/article/abs/pii/s0011916411004607 https://www.sciencedirect.com/science/article/abs/pii/s0011916411004607 https://www.sciencedirect.com/science/article/abs/pii/s0011916411004607 https://www.sciencedirect.com/science/article/abs/pii/s0011916411004607 https://www.sciencedirect.com/science/article/abs/pii/s0011916411004607 http://en.cnki.com.cn/article_en/cjfdtotal-hgyj200502007.htm http://en.cnki.com.cn/article_en/cjfdtotal-hgyj200502007.htm http://en.cnki.com.cn/article_en/cjfdtotal-hgyj200502007.htm http://en.cnki.com.cn/article_en/cjfdtotal-hgyj200502007.htm https://aip.scitation.org/doi/abs/10.1063/5.0000178 https://aip.scitation.org/doi/abs/10.1063/5.0000178 https://aip.scitation.org/doi/abs/10.1063/5.0000178 https://aip.scitation.org/doi/abs/10.1063/5.0000178 https://aip.scitation.org/doi/abs/10.1063/5.0000178 https://aip.scitation.org/doi/abs/10.1063/5.0000178 https://www.sciencedirect.com/science/article/abs/pii/s1383586607005321 https://www.sciencedirect.com/science/article/abs/pii/s1383586607005321 https://www.sciencedirect.com/science/article/abs/pii/s1383586607005321 https://www.sciencedirect.com/science/article/abs/pii/s1383586607005321 https://pubs.rsc.org/no/content/articlehtml/2016/cp/c6cp03238a https://pubs.rsc.org/no/content/articlehtml/2016/cp/c6cp03238a https://pubs.rsc.org/no/content/articlehtml/2016/cp/c6cp03238a https://pubs.acs.org/doi/pdfplus/10.1021/ie990488g https://pubs.acs.org/doi/pdfplus/10.1021/ie990488g h. s. wahab and s. a.m. mohammed / iraqi journal of chemical and petroleum engineering 21,4 (2020) 1 9 9 السائلةمن المياه الملوثة عن طريق األغشية االستومينوفينإزالة مخلفات مسلم محمد حسنى سالم وهاب و سوسن عبد العراق/ بغداد/ جامعة بغداد/ كلية الهندسة/ قسم الهندسة الكيمياوية الخالصة في هذا البحث تم دراسة ازالة مخلفات االدوية المضادة لاللتهابات )االستومينوفين( من المياه الملوثة .aliquate 336باستخدام االغشية السائلة وبوجود مادة حاملة وهي دراسة تأثير عدد من المتغيرات على عملية استخالص )االستومينوفين( من المحاليل المائية ,مثل ,التركيز تم ( جزء بالمليون لالستومينوفين, تركيز محلول كلوريد الصوديوم 50-10األبتدائي للمحلول المراد استخالصه ) ة , ونسبة حجم الماء الملوث الى السائل ( درجة سيليزي30,40,50( موالري ,درجة الحرارة )0.7, 0.5, 0.3) ( دورة بالدقيقه 75,100,130مللتر غشاء(,سرعة خلط المحلول المستخلص ) 80مللتر / 400-200الغشائي ) ( دورة بالدقيقة ,تركيز المادة الحاملة للمستخلص في السائل الغشائي 0,100,150,سرعة خلط السائل الغشائي ) (,نوع المذيب في السائل الغشائي )رابع كلوريد الكاربون , 2,4,6,8,10ضة )%( وزنًا, درجة الحمو 1,5,9) هيبتان(. %(.تم حساب حركية اإلنتقال 97أظهرت الدراسة نسبة استخالص عالية لالستومينوفين وتقدر بحوالي ) م التحقق من بإستخدام موديل انتقال يتألف من تفاعلين متعاقبين غير إنعكاسيين من المرتبة األولى .حيث ت حركية االنتقال لالستومينوفين في التجارب ذات أفضل الظروف. k1( و ثوابت سرعة االستخالص واإلنتزاع )rmmax( للوصول ألعلى تركيز خالل الغشاء ) tmaxالوقت الالزم) ( تم تحديد قيمها .jfmax ،jsmax( والتدفق االنتقالي األقصى خالل الغشاء )k2 و طاقة التنشيط لكال العمليتين )االستخالص واإلنتزاع ( لالستومينوفين وكانت القيم كالتالي: كذلك تم حساب يطرة لإلنتقال مول لالستومينوفين. إن طاقة التنشيط هذه أثبتت ان الخطوة المس\( كيلوجول1.826, 1.733) .هي عملية اإلنتشار 336معالجة المياه الملوثة, مادة الكوت االستومينوفين, االغشية السائلة,: االدوية المضادة لاللتهابات, الدالةالكلمات iraqi journal of chemical and petroleum engineering vol.12 no.1 (march 2011) issn: 1997-4884 estimation of mass transfer coefficients in a packed distillation column using batch mode adil a. al-hemiri and mohammed d. selman* baghdad university/ chemical engineering department thi qar university /college of engineering* abstract this research adopts the estimation of mass transfer coefficient in batch packed bed distillation column as function of physical properties, liquid to vapour molar rates ratio (l / v), relative volatility (α), ratio of vapour and liquid diffusivities (dv / dl), ratio of vapour and liquid densities (ρv / ρl), ratio of vapour and liquid viscosities (µv/ µl). the experiments are done using binary systems, (ethanol water), (methanol water), (methanol ethanol), (benzene hexane), (benzene toluene). statistical program (multiple regression analysis) is used for estimating the overall mass transfer coefficient of vapour and liquid phases (kov and kol) in a correlation which represented the data fairly well. kov = 3.3 * 10 -10 α -0.7 (dv / dl) 0.65 (l / v) 3.5 (ρv / ρl) 1.25 (μv / μl) -5.0 kol = 2.8 * 10 -6 α -0.95 (dv / dl) 0.03 (l / v) 1.15 (ρv / ρl ) 0.077 (μv / μl) -0.9 in this research a method where the resistances to mass transfer in both phases are accounted for separately through the use of htu-ntu model for each phase z=htuov.ntuov and z=htuol.ntuol results show that both overall vapour and liquid mass transfer coefficient are increased with liquid to vapour molar rates ratio, vapour to liquid diffusivities ratio and vapor to liquid densities ratio, but decreased with increasing the relative volatility and vapour to liquid viscosities ratio. key words: mass transfer coefficient; distillation; packed column. iraqi journal of chemical and petroleum engineering university of baghdad college of engineering estimation of mass transfer coefficients in a packed distillation column using batch mode vol.12 no.1 (march 2011) introduction batch distillation process is an important separation technique especially used in the fine specialty: pharmaceutical, biochemical and food industries. because the demand and the uncertainty in specifications for high-value-added and low volume specialty chemicals have increased recently, the use of batch distillation is becoming increasingly popular. instead of using many continuous columns in series, multiple products can be obtained from a single batch distillation column during a single batch run. moreover, batch distillation processes can easily handle variations both in the product specifications and in the feed composition. this flexibility of batch distillation processes provides the ability to cope with a market characterized by short product life times and strict specification requirements. batch operation should be considered when the qua ntity to be distilled is small; when it is produced at irregular intervals; when a range of products has to be produced; or when the feed composition is likely to vary considerably. a batch column is like the top half of a continuous column – it has a rectifying section only. a portion is returned to the column as reflux and the remainder is removed as distillate or top product [1]. interfacial mass transfer that is characterized by the partial volumetric mass transfer coefficients kla and kva is a common physical background of absorption and distillation. the knowledge of both coefficients is hence essential in the design of packed absorption and distillation columns. for every packing type correlations are used to describe the dependence of kla and kva on physical properties and conditions prevalent in an experimental apparatus. such correlations are based only on the absorption mass transfer data, for it is not possible to determine kla and kva separately by distillation experiments. but as the physical properties (especially temperature) in absorption and distillation column significantly differ, the correlations suitable for both processes should fit their influence accurately in a sufficiently wide range. up to now this requirement has not been fulfilled, so the use of the “absorption correlations” in the distillation column design is risky. in order to create a common mass transfer data correlation, the knowledge of kla and kva not only under absorption, but also under distillation conditions is necessary [2]. absorption and distillation have the same physical background –interfacial mass transfer between gas and liquid phase which is characterized by mass transfer coefficient in liquidkla and vapour/gaskva side. an effort to calculate the height equivalent to a theoretical plate (hetp) using absorption mass transfer coefficients recalculated to the conditions in distillation column has mostly led to large deviations from the experimental data (often higher than 50%). the discrepancy can be ascribed partially to large extrapolation in temperature used in adil a. al-hemiri and mohammed d. selman vol.12 no.1 (march 2011) the data transfer from absorption to distillation. however, the measurements of mass transfer coefficient directly in distillation columns are rare. in distillation namely, it is not possible to measure individual mass transfer coefficients by using a proper distillation system in which the overall resistance to the interfacial mass transfer is mainly due to one of the phases and to study behavior of the individual coefficients separately as it is possible in absorption [3]. kayihan, et.al [4], studied simultaneous heat and mass transfer distillation theoretically in a wetted wall column using methanol water binary system for one atmosphere distillation. confirmation of the liquid phase saturation was made through a comparison of the experimentally measured liquid temperatures with the calculated bubble point temperature. the authors deduced that all of the resistance to mass transfer was in the vapour phase. it was concluded that interphase diffusion is responsible for mass transfer in distillation and that there is no additional evaporation within the liquid phase. honorat, et.al [5] examined the simultaneous heat and mass transfer process in binery distillation by combining enthalpy and material balances around the liquid and vapour phases which makes it impossible to obtain the mass transfer coefficient from distillation experiments by measuring compositions and temperatures as functions of column height. their experiments carried out in a packed bed column at total reflux for the toluenetrichloroethylene system. krishnamurthy et.al [6] used a non-equilibrium stage model of countercurrent separation processes to model a packed distillation column and a packed absorber. a key feature of the model is that the component material and energy balance relations for each phase are solved simultaneously with the mass and energy transfer rate equations and interface equilibrium equations. computations of quantities such as hetp and htu are completely avoided. the terminal stream composition, flow rates, and temperature profiles over the packed depth predicted by the model are compared with results of field tests. they refer to that resistances to mass transfer and heat transfer in both phases are accounted for separately through the use of rate equations for each phase. lee et al [7], simulated a multi-component packed distillation [(methanol(1)/ethanol(2)/water(3)] using a rate-based model in which the so called merq (material balance, energy balance, rate equilibrium) equations in any segment of the packing are solved with an equation tearing technique. the simulation results are compared with the experimental results obtained from a 0.2 m diameter pilot-scale packed column using the published correlations to evaluate their applicability. lee et.al,[8] obtained concentration profile of the acetone-methanol-2-propopanol system experimentally using a batch distillation column packed with 1 cm pall rings which compared with theoretical profiles. they performed experiments under 1 atm, total reflux condition and used matrix model for calculating theoretical concentration profiles. they estimated mass transfer coefficient and the height of transfer unit by empirical equation of onda et al [9] and billet [10]. their calculated profiles estimation of mass transfer coefficients in a packed distillation column using batch mode vol.12 no.1 (march 2011) were in reasonable agreement with the experimental profiles. the objective of this research is determining the overall mass transfer coefficient based on the vapour and liquid phase from temperature composition experimental data using htu-ntu model in a batch packed distillation column . effect of verifying physical properties (relative volatility (α), ratio of vapour and liquid densities (ρv/ρl), ratio of vapour and liquid viscosities (μv / μl), ratio of vapour to liquid diffusivities (dv / dl), vapour flow rates (v) and liquid flow rates (l) under various reflux ratio values. binary system is used for all the experiments (ethanol-water, methanol-water, ethanol-methanol, benzenehexane and benzene-toluene. multiple regression model (statistical program) used for estimating overall mass transfer coefficient of vapour and liquid phases. experimental a column of 0.5-m diameter and 1.5 m high was used for the distillation column as shown in fig. (1). the column was filled with 10 mm of glass raschig rings. the unit comprised of: 1. reboiler system (electrically heated): total working capacity (vessel+heater): 28 litters. 1.1spherical vessel: working capacity (13 litters). 1.2heat exchanger: electrical immersion type: rating at 240 volt, 50 hz, single phase 6kw maximum. 2. reflux flow meter (ri.1a): variable area type range (0-7.5) litters/min. 3. product distillate flow meter (ri.1b.): variable area type range (0-7.5) litters/min. 4. product distillate flow meter (ri.1c.): graduate tube calibrated in milliliters. 5. cooling water flow meter (fi.2.): variable area type, range (0-15) litters/min. 6. water pressure indicator: bourdan type, range (0-4) bar range. 7. column temperature indicator (ti.1,2,3) , locally mounted, mercury in glass thermometer range (20-120oc). 8.reboiler temperature indicator (ti.4) remote reading filled system, dial thermometer, range (0-50oc) 9.cooling water temperature indicators (ti.5, ti.6) remote reading dial thermometer, range (0-50oc). 10. electrical heated version: hc.4 heater control: thyristor phase angle. power controller i.4: ammeter moving iron type. range (0-40) amps e.4: voltammeter moving iron type (0-240 v). the reboiler vessel is charged with chemical mixture (0.5 mole fraction) through the charge-port and valve v.6 and evaporated in the thermosyphone reboiler. the temperature of the boiling liquid is obtained from the temperature indicator ti.4. vapours from the reboiler enter at the base of the distillation column which is packed with glass raschig rings. liquid and vapour temperatures across each packed adil a. al-hemiri and mohammed d. selman vol.12 no.1 (march 2011) section are given by temperature indicators ti.1 to ti.3 inclusive. at first, the column was set to operate at total reflux condition, allowing a period of fifteen minutes for the equipment to maintain thermal equilibrium with the surroundings. vapors leaving the top of the column are totally condensed to liquid distillate in the overhead condenser and pass to the reflux control flow meters ri.1a and ri.1b. ri.1a indicates the quantity of distillate returned to the column as reflux, while ri.1b indicates the quantity of distillate removed as product. the desired reflux ratio is given by the ratio of the rotameter (ri.1a and ri.1b) scale reading which present the reflux ratio. a graduated cylinder ri.1c positioned in the product distillate line below the product cooler enables the volumetric flow rate to be measured. temperature of the reboiler (ti.4) and top temperature (ti.1) are read experimentally and from temperature/equilibrium data, compositions are calculated. overall material balance was applied for measuring distillate mole fraction. the differential height technique for a given packed distillation column, overall liquid mass transfer coefficients (kov, kol) are calculated according to the htu-ntu model. z=htu.ntu (1) according to eq. (1) the overall vapour mass transfer coefficient obtained from htuov (overall height of mass transfer units) and number of overall vapour phase transfer units (ntuov) which are defined by the concentrations of the boiler and top of the column(at packing height 1.5 m), dependent on the separation task and physicalproperties. z=htuov.ntu ov (2) z=htuol.ntuol (3)    * yy dy ak s v z ov (4) x x y )1(1 .*     (5) the the a the mount of distillate and distillation component is computed from material balance on the column: so-s1=d (6) soxso-s1xs1=dxd (7) s1: s1: s1: s1: amount of mixture in the reboiler at any run, which is computed from rayliegh equation:                   )1( )1( ln )1( )1( ln 1 1 ln 11 1 1 s so sso soso x x xx xx s s  (8) temperat temperature composition curve [11] is used for measuring mole fractions. the same procedure is applied for overall liquid phase mass transfer coefficient calculation:    xx dx ak s l z ol * (9) y y x )1( *    (10) set of experiments are carried out under various reflux ratio values which calculated from minimum reflux ratio, the last is measured from vapour liquid equilibrium curve, then the reflux ratio used for the experiments as (1.1, 1.3 and 1.5) of the minimum reflux ratio. the physical properties are estimated from the references [1, 12]. estimation of mass transfer coefficients in a packed distillation column using batch mode vol.12 no.1 (march 2011) results and discussion overall mass transfer coefficient for vapour and liquid phases are evaluated from htu-ntu model as function of physical properties for vapour and liquid phases (viscosities and densities), transport properties (relative volatility and diffusivity) and vapour and liquid molar rates under various reflux ratio values. it was concluded that interphase diffusion is responsible for mass transfer in distillation and that there is no additional evaporation within the liquid phase caused by heat transfer from the vapour phase as proposed by some previous investigators. honart and orville[5] confirmed the same in a distillation packed column, i.e., the zero resistance to mass transfer in the liquid phase. an assumption that all of the resistance to mass transfer is in the vapour phase has been used in many application of simultaneous heat and mass transfer model for multicomponent distillation. for example, pelkonen et.al [13] used the model for the evaluation of the vapour phase mass transfer coefficient in a wetted wall column in the benzene-toluene-ethylbenzene ternary system and assumed a total resistance to mass transfer in the vapour phase. in the present work, resistances to mass transfer in both phases are accounted for separately through the use of htu-ntu model for each phase. the mathematical expression for mass transfer in distillation column using binary system can be expressed as:   lvlvab ol ov vldf k k  ,,,,,,,       (11)     54321 1 )()( a l va v vaa l va ov l v l d d ck        (12)     54321 2 )()( a l va v vaa l va ol l v l d d ck        (13) where:  relative volatility. dv and dl: vapour and liquid diffusivity (m 2 /sec).       v l : liquid and vapour molar rates ratio. v v l    : liquid and vapour densities. l v   : liquid and vapour viscosities. c1, c2: constants which have the unit of mass transfer coefficient. a1-a5: indices. estimation of mass transfer coefficient is done using multiple regression model (statistics program), which gives the correlation factors for both overall liquid and vapour phase transfer coefficients: kov = 3.3 * 10 -10 α -0.7 (dv / dl) 0.65 (l / v) 3.5 (ρv / ρl) 1.25 (μv / μl) -5.0 kol = 2.8 * 10 -6 α0.95 (dv / dl) 0.03 (l / v) 1.15 (ρv / ρl) 0.077 (μv / μl) -0.9 the experimental data and the detailed analysis may be found elsewhere [14]. effect of liquid molar rate (l) on kov and kol: most of the distillation data used in the correlation were reported under total reflux conditions, thus a separation of the liquid and vapour rates effect could not be studied from the previous available data. overall mass transfer coefficient based on vapour and liquid phase (kov) and (kol) adil a. al-hemiri and mohammed d. selman vol.12 no.1 (march 2011) increased with increasing liquid molar rate, since as the liquid molar rate increased, the overall mass transfer coefficient based on vapour and liquid phase (kov) and (kol) increased with increasing liquid molar rate, since as the liquid molar rate increased, the liquid distribution in the bed is improved and mass transfer coefficient increased, because a good liquid distribution enhanced the contact of the gas and the liquid in the packed section. the effective transfer area should be proportional to the liquid rate since increased liquid velocity would provide a more effective renewal of the liquid film. effect of vapour molar rate (v) on kov and kol: both (kov) and (kol) decreased with increasing the vapour rate (v). this may be due to that when increasing the vapour molar rate, the thickness of the concentration boundary layer on the vapour side at the vapour-liquid interface becomes thinner, this result in a lower mass transfer coefficient which is inversely proportional to the thickness of the concentration boundary layer. vapour and liquid viscosities ratio effect: the overall vapour and liquid mass transfer coefficient (kov) and (kol) decreased with increasing the ratio of vapour to liquid viscosity , i.e when the vapour viscosities increased the coefficients decreased, this can be attributed both to the reduction in mass diffusivity. also when liquid viscosity increased the coefficients decreased, this effect may be due to the maximum wettability obtained and ripples are formed when liquid viscosity increased. effect of ratio of vapour and liquid densities: the overall vapour and liquid mass transfer coefficient (kov) and (kol) increase with increasing densities ratio as expected. the overall vapour and liquid mass transfer coefficient (kov) and (kol) increase with increasing densities ratio as expected. these these results tend to the increasing of vapour and liquid masses. as the mass of the vapour increased, it may cause ripples to form on the liquid film (especially at the end effects) and thus increase the mass transfer coefficient. also when the mass of the liquid increased, the column holdup increased such that the empty spaces within the bed close up and the liquid flows downwards as a continuous phase. the gas phase then rose up through the liquid layer in the form of bubbles, these all tend to decrease the mass transfer coefficient. effect of ratio of vapour and liquid diffusivities: vapour and liquid mass transfer coefficient increased with increasing the ratio which tend to that increasing kov with increasing dv and kol with decreasing dl. the mass transfer between the vapour and liquid phases results from the combined contribution of molecular diffusion and a bulk transport of material through the interface. both vapour and liquid diffusivities are proportional to the temperature, therefore its values increased together to give increasing index with mass transfer coefficient values. conclusions the overall vapour and liquid mass transfer coefficients (kov and kol) increased with increasing the liquid to vapour molar rate ratio (l/v), the diffusivity ratio (dv /dl), the density ratio (ρv / ρl). however, the effect on kov is more pronounced as indicated by the powers on these parameters in the resulting final equations. but the coefficients decreased with the viscosity ratio and the effect on kov is larger than on kol. estimation of mass transfer coefficients in a packed distillation column using batch mode vol.12 no.1 (march 2011) finally both kov and kol decreased with increasing the relative volatility (α) and at nearly the same order of magnitude. nomenclature d distillate flow rate k mole/s. a specific area of packing (m 2 /m 3 ) a constants k mass transfer coefficient kmole/m 2 s. n number of moles k mole htu height of transfer unit, m. ntu number of transfer unit. l liquid molar rate, kmole/hr. v vapour molar rate, kmole/hr. s moles of feed in the still, kmole. y mole fraction, vapour phase. x mole fraction, liquid phase. t temperature (k). dv vapour diffusivity (m 2 /s.) dl liquid diffusivity (m 2 /s.) z column height (m) subscript: b bottom t top ol overall liquid ov overall vapour s still greek letters  kinematic viscosity, kg/m.s  density , kg/m 3  relative volatility. references 1. perry h. (1997) “perry,s chemical engineers handbook", mc-graw hill inc. 2. reji j., linek k., moucha t., prokovopva e., and valenz l. (2006) "vapour and liquid side volumetric mass transfer coefficients measured in distillation column: comparison with data calculated from absorption correlations", vol.61 pp(6096-6108). 3. linek v., moucha t., prokopova e. and reji j. (2005) "simultaneous determination of vapour and liquid side volumetric mass transfer coefficient s in distillation column", chem.eng.res.des., vol.83 pp(979-986). 4. kayihan f., orvelle c. and mellichamp a. (1977) "simultaneous heat and mass transfer in binary distillation", chem.eng.sci., vol.32 pp. (747-754). 5. honorat a. and orville c. (1978) "simultaneous heat and mass transfer in a packed binary distillation column", chem.eng.sci., vol33 pp(635-640). 6. krishnamurthy r. and tayler r. (1985) "simultaneous of packed distillation and absorption columns", ind.eng.chem.proc.des.dev., vol.24 pp(513-524). 7. lee y., kim g., dong m. and oda a. (1997) "analysis of packed distillation columns with a rate-based model", korean j. of chem.eng.sci., vol.35 pp (2337-2343). 8. lee y. and dong p. (1999) "estimation of concentration profiles of the acetonemethanol-2-propanol system in a batch packed bed distillation column", j.korea inst.chem.eng., vol.37, no.3 pp(453-458). 9. onda k., takeuchi h. and okumoto y. (1968) "mass transfer coefficients between gas and liquid phases in packed columns", chem.eng.jap. vol.1, no.1 (1968) . 10. billet r. and schultes m. (1999) "prediction of mass transfer columns with dumped and arranged packings"inst.chem.eng.,vol.77 pp(498504). adil a. al-hemiri and mohammed d. selman vol.12 no.1 (march 2011) 11. chen j., (1950) "distillation equilibrium data", reinhold, new york. 12. robert c., john m. and poling e. "(1978) "the properties of gases and liquids", mc-graw hill inc., fourth edition. 13. pelkonon s., kaeseman r. and goral a. (1997) "distillation lines for multicomponenet sepatation in a packed columns, theory and comparison with experiments", ind.eng.chem.res., 36: (5392-5398). 14. selman m. d., “estimation of mass transfer coefficient in a packed bed distillation column using batch mode”, ph.d. thesis, chemical engineering department, baghdad university (2009). available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.21 no.1 (march 2020) 15 – 21 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: noor a. mohammed, , email: mn.r_86@yahoo.com, name: abeer i. alwared, email: abeerwared@yahoo.com, name: mohammed s. salman, email: iraqmas68@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. photocatalytic degradation of reactive yellow dye in wastewater using h2o2/tio2/uv technique noor a. mohammed a , abeer i. alwared a and mohammed s. salman b a department of environmental engineering/ college of engineering/ university of baghdad b avi-cenna e-learning center / university of baghdad abstract in the present study, advanced oxidation treatment, the tio2 /uv/h2o2 process was applied to decolorisation of the reactive yellow dyes in aqueous solution. the uv radiation was carried out with a 6 w low-pressure mercury lamp. the rate of color removal was studied by measuring the absorbency at a characteristic wavelength. the effects of h2o2 dosage, dye initial concentration and ph on decolorisation kinetics in the batch photoreactor were investigated. the highest decolorisation rates were observed (98.8) at ph range between 3 and 7. the optimal levels of h2o2 needed for the process were examined. it appears that high levels of h2o2 could reduce decolorisation by scavenging the *oh. the color degradation rate decreases as the dye concentration increases. the rate coefficient (k=0.0319 min -1 ) of degradation, follows the pseudo-first-order kinetics. keywords: reactive yellow dye; titanium dioxide; hydrogen peroxide; advanced oxidation processes received on 13/05/2019, accepted on 08/07/2019, published on 30/03/0220 https://doi.org/10.31699/ijcpe.2020.1.3 1introduction in recent years, the treatment of textile and dyeing wastewater coming from textile industries and other related industries has received the increasing attention because of the high yield, low biodegradability and the high toxicity of this wastewater. the artificial dyes are organic compounds with complex molecular structures and big molecular weights, which are using in chemical industries especially in the textile industry. most of them are considered non –toxic, although some of them are not totally innocuous because they made of known carcinogens such as benzidine ‎[1]. the pollution problem is different for the various types of fibers. color is the first contaminant to be recognized in the wastewater and has to be removed before discharging into water bodies or on land. the presence of very small amounts of dyes in water (less than 1 ppm for some dyes) is highly visible and affects the aesthetic merit, water transparency and gas solubility in lakes, rivers and other water bodies ‎[2]. therefore, it is necessary to find an effective method of wastewater treatment in order to remove the color from textile effluents. there are different convention methods, such as chemical precipitation and separation of pollutants, electrocoagulation ‎[3], elimination by adsorption on activated carbon etc., are currently used. one difficulty with these methods is that they are not destructive but only transfer the contamination from one phase to another, therefore a new and different kind of pollution is faced and further treatments are deemed necessary ‎[4]–‎[7]. advanced oxidative processes (aops) offer a possible solution to this problem. they allow the degradation of pollutants by highly oxidizing species, such as hydroxyl radicals, generated in the reaction medium. the most widely used techniques are fenton and photo-fenton reactions ‎[8],‎[9], uv/h2o2, uv/o3 and o3 systems ‎[10] and heterogeneous photocatalysis with metal oxides such as ti and zn ‎[11]. among aops, heterogeneous photocatalysis using tio2 as photocatalyst appears as the most emerging destructive technology ‎[12]. the aim of the present work is to investigate the influence of various parameters on photocatalytic decomposition of an azo dye, called reactive yellow (ry) also to evaluate the degradation efficiency of simulated textile wastewater. the effect of the addition of h2o2 was also studied for enhancing of azo dye and the presence of unsupported suspended tio2 powder, which is irradiated by the uv-c light. heterogeneous photocatalysis has been shown to be potentially advantageous as it may lead to the complete mineralization of pollutants to co2, water, and mineral acids ‎[13]. 2experimental 2.1. materials the commercial azo dye reactive yellow, (ry), fig. 1, obtained from al-hilla textile factory south of baghdad, (department of dying and printing). https://doi.org/10.31699/ijcpe.2020.1.3 n. a. mohammed, et al. / iraqi journal of chemical and petroleum engineering 21,1 (2020) 15 21 61 tio2-p25, powder supplied by fluka (china) with 99% purity (molecular weight 79.87g/mol). the hydrogen peroxide (50% w/w) was obtained from merck. the natural ph of the aqueous dye solution was 7. the experimental solutions were adjusted to the decided ph. fig. 1. chemical structure of reactive yellow ‎[14], ‎[15], ‎[16] 2.2. irradiation experiments all photocatalytic and photochemical experiments were carried out in a batch mode laboratory-scale reactor. the reactor consisted of pyrex glass cylinder 3 l volume with a magnetic stirrer and (msh-300n, boeco, hamburg, germany). uv radiation (254 nm) was generated from a uv lamp (tuv 6 w 4p-se, philips, guildford, surrey, england), which was fixed vertically at the top of the reactor. the lamp was totally immersed in the content of the cylindrical reactor. the uv lamp was sheathed in a quartz sleeve for protection. the distance between the lamp and the reactor wall was fixed at 5 cm to ensure maximum light irradiation. the turbidity of the solution was measured using a turbidity meter (hanna microprocessor, padua, italy). the initial ph of the solution was monitored using a ph meter (inolab 72, wtw co., weilheim, germany). 2.3. procedure and analysis the desired concentration of dye’s stock (20, 50, 75 and 100 mg/l) was prepared and the ph was adjusted, before adding the reagents, by adding a dilute solution of hcl or naoh to the reactor contents. tio2 was added to the solution with (25, 50, 75 and 100 mg/l) and then the hydrogen peroxide (100, 250, 400 and 700 mg/l). the solution was then subjected to stirring using a magnetic stirrer at 200 rpm for 120 min. the suspension was magnetically stirred in the dark for 66 min to attain primary adsorption equilibrium between dye and tio2. h2o2 was added after that. then, the lamp was switched on to initiate the reaction. during irradiation, agitation was maintained to keep the suspension homogenous. irradiation was carried out in the open-air condition. at specific time intervals, 10 ml of the sample was withdrawn and centrifuged at (3000 rpm for 15 min) to separate the catalyst. the concentration of dye in each sample was determined by a spectrophotometer (uv-vis spectrophotometer perkin–elmer 55 ose) at λmax = 420 nm and a calibration curve fig. 2 the percentage of decolorization was calculated as follows: ( ) (1) where: co = initial concentration of dye solution. c = final concentration of dye solution. fig. 2. calibration curve in wavelength 420 nm fig. 3. photograph and schematic diagram of the batch reactor 3results and discussion 3.1. effect of initial ry-14 concentration the effect of the initial concentration of ry -14 dye on the photocatalytic efficiency was investigated with concentrations ranging from 20 to 100 mg/l fig. 4 at tio2=25 mg/l, h2o2 =400 mg/l and ph=7. from this figure, the sample was taken after 10 min from the experiment began; it was observed that the photodegradation conversion of ry-14 decreases with an increase in the initial concentration of ry. the presumed reason is that when the initial concentration of dye is increased, more and more dye molecules are adsorbed on the surface of tio2. a large amount of adsorbed dye is thought to have an inhibitive effect on the reaction of dye molecules with photogenerated holes or hydroxyl radicals, because of the lack of any direct contact between them. once the concentration of dye is increased, it also causes the dye molecules to absorb light and the photons never reach the photocatalyst surface, thus the photodegradation efficiency decreases ‎[17]. y = 0.0119x 0.0103 r² = 0.9822 0 0.05 0.1 0.15 0.2 0.25 0 5 10 15 20 25 a b so rb a n ce concentration (ppm) n. a. mohammed, et al. / iraqi journal of chemical and petroleum engineering 21,1 (2020) 15 21 61 fig. 4. influence of initial ry dye concentration on dye degradation by the photocatalytic system at h2o2=400 mg/l, tio2 =25 mg/l and ph=7 3.2. effect of the amount of photocatalyst the effect of the amount of tio2 on the ry removals was studied at a concentration (25,50,75 and 100) mg/l while keeping other parameters constant (c=20 mg/l, h2o2=400 mg/l, ph=7), and their results were plotted as shown in fig. 5. the photodegradation efficiency increases with an increase in the amount of photocatalyst reach the higher value of catalyst amount (25 mg/l) and then decreases. the most effective decomposition of ry was observed with 25mg/l of tio2. the reason of this observation is thought to be the fact that when all dye molecules are adsorbed on tio2, while the tio2 is exposed to uv light, the conduction band electrons (e−) and valence band holes (h+) are generated with light energy greater than its bandgap energy (eg,3.2 ev), eq. (2-5) .the photogenerated electrons could reduce the dye or react with electron acceptors such as o2 adsorbed on the tio2 surface or dissolved in water, reducing it to superoxide radical anion o2 •− . the photogenerated holes can oxidize the organic molecule to form r + or react with oh − or h2o oxidizing them into oh • radicals. together with other high oxidant species (peroxide radicals) they are reported to be responsible for the heterogeneous tio2 photodecomposition of organic substrates as dyes, refers to eq. (6-9). the addition of higher quantities of tio2 would have no effect on the degradation efficiency. another cause for this is supposedly an increased opacity of the suspension works as a shading effect, brought about as a result of an excess of tio2 particles ‎[18], ‎[19]. tio2 + hν(λ < 390 nm) → tio2(e−cb+ h+vb) (2) tio2(hvb+)+ h2o → tio2 + h+ + oh• (3) tio2(hvb+) + oh− → tio2 + oh• (4) tio2(ecb−) + o2 → tio2 + o2•− (5) o2•− + h+ → ho2• (6) dye + oh• → degradation products (7) dye + hvb+ → oxidation products (8) dye + ecb− → reduction products (9) fig. 5. effect of initial titanium dioxide (tio2) concentrations on dye degradation by the photocatalytic system at h2o2=400 mg/l, dye concentration 20 mg/l and ph=7 3.3. effect of the initial ph in order to study the effect of the initial ph in the photocatalytic process, different values of ph (3, 5, 7,10and 11) were carried out at h2o2 = 400 mg/l, dye conc. = 20 mg/l, tio2 = 05 mg/l and there results shown in fig. 6, from this figure it can be noticed that the removal efficiency increases to reach a maximum of 98.85% at ph=7 because the difference between the degree of photodegradation of ry in acidic solution (ph=3 and neutral ph=7) was only 4 %, the following experiments were carried out with neutral ph, this agrees with the previous study by ‎[20]. this may be attributed to the electrostatic interactions between the positive catalyst surface and dye anions leading to the strong adsorption of the latter on metal oxide support . the interpretation of ph effects on the efficiency of dye photodegradation process is very difficult task because of its multiple roles, this is because three possible reaction mechanisms can contribute to dye degradation, (1) hydroxyl radical attack, (2) direct oxidation by the positive hole, and (3) direct reduction by the electron in the conducting band. the contribution of each one depends on the substrate nature and ph ‎[21]. moreover, the positive holes are considered as the major oxidation species at low ph which react with hydroxide ions forming hydroxyl radicals, thus the efficiency of the process is enhanced. with high ph, there is columbia repulsion between the negatively charged surface of the catalyst and the hydroxide anions which prevent the formation of oh˚ and decrease the photocatalytic degradation ‎[22]. 0 20 40 60 80 100 0 30 60 90 120 % r e m o v a l e ff ic ie n cy time(min)mn c0 20 mg/l c0 50 mg/l c0 75 mg/l c0 100 mg/l 0 20 40 60 80 100 0 30 60 90 120 r e m o v a l e ff ic ie n cy % time (min),k 50 mg/l 25 mg /l 75 mg/l 100 mg/l n. a. mohammed, et al. / iraqi journal of chemical and petroleum engineering 21,1 (2020) 15 21 61 fig. 6. effect of ph on dye degradation by the photocatalytic system at h2o2=400 mg/l, dye concentration 20 mg/l and tio2=25mg/l 3.4. effect of addition of h2o2 the photocatalytic degradation of ry was a focus in this study at different hydrogen peroxide concentrations up to (400 mg/l), the results are given in fig. 7. the higher reaction rates after the addition of peroxide were attributed to the increase in the concentration of hydroxyl radicals. at a low concentration of hydrogen peroxide, it inhibits the electron-hole recombination, according to eqn. 10, and it could act as an alternative electron acceptor to oxygen eqn11 because hydrogen peroxide is a better electron acceptor than molecular oxygen according to eqn. 12 this agrees with the previous study by ‎[23]. the degradation rate of ry increased with increasing h2o2 concentration up to 400 mg/l, but above this value there was a decrease in the degradation rate that could be due to by scavenging effect as •oh according to eqns.13and14 it became predominant, this agree with a previous study ‎[24]. tio2(e-)+ h2o2 → tio2 + oh− + •oh (10) •o −2 + h2o2 → oh− + •oh + o2 (11) h2o2 + hv → 2•oh (12) h2o2 + •oh → ho2• + h2o (13) ho2• + •oh → h2o + o2 (14) fig. 7. effect of h2o2 addition on photodegradation efficiency of ry-14 [ry] = 20 mg/l, tio2 = 25mg/l, ph=7 3.5. reaction rate constant for heterogeneous photocatalyst the experimental data for dye degradation can be fitted according to pseudo-first-order and pseudo-second-order. the linearized form of pseudo-first-order and secondorder kinetic models can be given in eqn. (15) and (16) reported in ‎[25]. [ ] [ ] (15) [ ] [ ] (16) where; co is the initial concentration of dye and c is the concentration at irradiation time t, k and k1 are the pseudo-firstand pseudo-second-order rate constants in min -1 and l.mg -1 .min -1 , respectively , t is the irradiation time (in min). plot of [ ] [ ] , and [ ] [ ] versus time for each experimental lead to a straight line whose slope are k and k1, respectively ‎[20]. the regression analysis of the concentration curves versus reaction time indicates that the decomposition rate of this compound could be described by 1st order kinetics. the results are summarized in table 1. table 1. reaction rate constants in heterogeneous photocatalyst heterogeneous photocatalyst ; h2o2=400mg/l , dye=20mg/l, ph=7 ,tio2=50mg/l r 2 second order k1x10 6 l.mg -1 .min -1 r 2 first order kx10 3 min -1 removal efficiency 0.8107 0.0328 0.98 0.0319 98.8 4conclusion h2o2/tio2/ uv was used to examine the performance of aop for the degradation of ry dye wastewater. the reaction was influenced by the input concentration of h2o2, ph, the amount of tio2 and the concentration of ry in the wastewater. 95.8 85.88 99.85 80.79 75.85 70 75 80 85 90 95 100 r e m o v a l e ff ic ie n c y % ph 3 5 7 10 11 0 20 40 60 80 100 0 30 60 90 120 r e m o v a l e ff ic ie n cy % time (min),m 100 h2o2 250 h2o2 400 h2o2 700 h2o2 n. a. mohammed, et al. / iraqi journal of chemical and petroleum engineering 21,1 (2020) 15 21 61 the addition of the proper amount of hydrogen peroxide could improve the photodegradation rate. however, at high concentrations, h2o2 would quench hydroxyl radicals. the reaction was found to be of a first-order throughout the systems. the removal efficiency for the system at best h2o2/tio2/ uv conditions and dosage (h2o2 = 400mg/l, ph=7, , tio2=25mg/l) for 20mg/l load was found to be 98.8%. references [1] i. faisal, “removal of dyes from polluted water by adsorption on maize cob”, ijcpe, vol. 11, no. 1, pp. 55-57, mar. 2010. [2] w. taher mohammed, h. f. farhood, and a. hassoon bjaiyah al-mas’udi, “removal of dyes from wastewater of textile industries using activated carbon and activated alumina”, ijcpe, vol. 10, no. 1, pp. 43-52, mar. 2009. [3] m. yousuf, a. molla, r. schennach, j.r. parga, d.l .cocke ( 0226( ,photocatalytic degradation of azo dye acid red 14 in water: investigation of the effect of operational parameters,j. hazard. mater. b, vol. 84 , p.29. [4] huseyin selcuk (2005) , decolorization and detoxification of textile wastewater by ozonation and coagulation processes , dyes and pigments 64, p 217222. [5] n. daneshvar, , d. salari, , & a. r. khataee, "photocatalytic degradation of azo dye acid red 14 in water on zno as an alternative catalyst to tio2" , journal of photochemistry and photobiology a: chemistry 162.2-3 (2004): 317-322. [6] w.s. kuo, p.h. ho, solar "solar photocatalytic decolorization of methylene blue in water." chemosphere 45, no. 1, pp. 77-83 (2001). [7] garcia, j.c., oliveira, j.l., silva, a.e.c., oliveira, c.c., nozaki, j.,souza, n.e., 2007. comparative study of the degradation of real textile effluents by photocatalytic reactions involving uv/tio2/h2o2 and uv/fe2+/h2o2 systems. journal of hazardous materials 147, 105–110. [8] pe´rez, m., torrades, f., domenech, x., peral, j., 2002. fenton and photo-fenton oxidation of textile effluents. water research 36, 2703–2710. [9] azbar, n., yonar, t., kestioglu, k., 2004. comparison of various advanced oxidation processes and chemical treatment methods for cod and color removal from a polyester and acetate fiber dyeing effluent. chemosphere 55, 35–43. [10] rodrigues, a.c., boroski, m., garcia, j.c., shimada, n.s., nozaki, j.,hioka, n., 2008. treatment of paper pulp and paper mill wastewater by coagulation– flocculation followed by heterogeneous photocatalysis. journal of photochemistry and photobiology a: chemistry ,vol.194, p.1–10. [11] a.h. mounteer, r.o. pereira, a.a. morais, d.b. ruas, d.s.a. silveira, d.b. viana and r.c. medeiros. (2007). advanced oxidation of bleached eucalypt kraft pulp mill effluent ,vol .55 ,no. 6 , p. 109–116. [12] qamar, m., saquib, m., muneer, m.,(2005). photocatalytic degradation of two selected dye derivatives, chromotrope 2b and amido black 10b, in aqueous suspensions of titanium dioxide. dyes and pigments 65, 1–9. [13] i.k. konstantinou, t.a. albanis, "tio2-assisted photocatalytic degradation of azo dyes in aqueous solution: kinetic and mechanistic investigations: a review, appl. catal. b, vol. 49 ,p.1–14, 2004. [14] rachakornlij, m., ruangch, s. and teachakul, s., 2004, "removal of reactive dyes from aqueous solution using bagasse fly ash", journal of science and technology thailand, vol. 26, no. 1, pp. 13-24. [15] manu, b. and chaudhari, b. m., 2003,"decolorization of indigo and azo dyes in semi continuous reactors" j. process biochemistry, march, vol. 38, issue 8, pp. 12131221. [16] e. m. saggioro, a. s. oliveira, t. pavesi, c. g. maia, l. f. v. ferreiea, and j. c. moreira, (2011).use of titanium dioxide photocatalysis on the remediation of model textile wastewaters containing azo dyes, molecules 16, 10370 [17] daneshvar n. , salari d. , khataee a.r., (2003) , photocatalytic degradation of azo dye acid red 14 in water : investigation of the effect of operational parameters , journal of photochemistry and photobiology chemistry vol. 157, p. 111–116 [18] v. maurino, c. minero, e. pelizzetti, m. vincenti, coll. surf. a , (1999) chemical processes in marine environments ,151 , p.329. [19] s.r. cater, m.i. stefan, j.r. bolton, a. safarzadehamiri, (2000) ,photocatalytic degradation of azo dye acid red 14 in water:investigation of the effect of operational parameters, environ. sci. technol.,vol. 34, p. 659. [20] m. stylidi, d.i. kondarides, x.e. verykios, (2004) visible light-induced photocatalytic degradation of acid orange 7 in aqueous tio2 suspensions, appl. catal. b, vol. 47, p. 189–201. [21] rossetti, i. compagnoni, m. ramis ,g. freyria, francesca, (2017). development of unconventional photocatalytic reactors and processes for the abatement of harmful n -containing pollutants, chemical engineering transactions, vol.57 , p.319-324. [22] muruganandham, m., sobana, n. and swaminathan, m. (2006) solar assisted photocatalytic and photochemical degradation of reactive black 5. journal of hazardous materials, 137, 1371-1376. [23] lachheb, h., puzenat, e., houas, a., ksibi, m., elaloui, e., guillard, c and herrmann, j.-m. (2002) photocatalytic degradation of various types of dyes (alizarin s, crocein orange g, methyl red, congo red, methylene blue) in water by uv irradiated titania. applied catalysis b: environmental,vol. 39, p. 75-90. [24] chaudhuri, m., elmolla, e. s. and othman, r., 2009," removal of reactive dyes from aqueous solution by adsorption coconut coir activated carbon", 2nd international conference on engineering technology (icet 2009), december, kuala lumpur. [25] f. m. hameed and k. m. mousa, “study on kinetic and optimization of continuous advanced oxidative decolorization of brilliant reactive red dye”, ijcpe, vol. 20, no. 1, pp. 9-14, mar. 2019. http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/369 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/369 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/369 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/397 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/397 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/397 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/397 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/397 https://www.sciencedirect.com/science/article/abs/pii/s0304389401001765 https://www.sciencedirect.com/science/article/abs/pii/s0304389401001765 https://www.sciencedirect.com/science/article/abs/pii/s0304389401001765 https://www.sciencedirect.com/science/article/abs/pii/s0304389401001765 https://www.sciencedirect.com/science/article/abs/pii/s0304389401001765 https://www.sciencedirect.com/science/article/abs/pii/s0143720804001147 https://www.sciencedirect.com/science/article/abs/pii/s0143720804001147 https://www.sciencedirect.com/science/article/abs/pii/s0143720804001147 https://www.sciencedirect.com/science/article/abs/pii/s0143720804001147 https://www.sciencedirect.com/science/article/abs/pii/s1010603003003782 https://www.sciencedirect.com/science/article/abs/pii/s1010603003003782 https://www.sciencedirect.com/science/article/abs/pii/s1010603003003782 https://www.sciencedirect.com/science/article/abs/pii/s1010603003003782 https://www.sciencedirect.com/science/article/abs/pii/s1010603003003782 https://www.sciencedirect.com/science/article/pii/s004565350100008x https://www.sciencedirect.com/science/article/pii/s004565350100008x https://www.sciencedirect.com/science/article/pii/s004565350100008x https://www.sciencedirect.com/science/article/abs/pii/s0304389406015263 https://www.sciencedirect.com/science/article/abs/pii/s0304389406015263 https://www.sciencedirect.com/science/article/abs/pii/s0304389406015263 https://www.sciencedirect.com/science/article/abs/pii/s0304389406015263 https://www.sciencedirect.com/science/article/abs/pii/s0304389406015263 https://www.sciencedirect.com/science/article/abs/pii/s0043135401005061 https://www.sciencedirect.com/science/article/abs/pii/s0043135401005061 https://www.sciencedirect.com/science/article/abs/pii/s0043135401005061 https://www.sciencedirect.com/science/article/pii/s0045653503010609 https://www.sciencedirect.com/science/article/pii/s0045653503010609 https://www.sciencedirect.com/science/article/pii/s0045653503010609 https://www.sciencedirect.com/science/article/pii/s0045653503010609 https://www.sciencedirect.com/science/article/pii/s0045653503010609 https://www.sciencedirect.com/science/article/abs/pii/s1010603007003541 https://www.sciencedirect.com/science/article/abs/pii/s1010603007003541 https://www.sciencedirect.com/science/article/abs/pii/s1010603007003541 https://www.sciencedirect.com/science/article/abs/pii/s1010603007003541 https://www.sciencedirect.com/science/article/abs/pii/s1010603007003541 https://www.sciencedirect.com/science/article/abs/pii/s1010603007003541 https://iwaponline.com/wst/article-abstract/55/6/109/12367 https://iwaponline.com/wst/article-abstract/55/6/109/12367 https://iwaponline.com/wst/article-abstract/55/6/109/12367 https://iwaponline.com/wst/article-abstract/55/6/109/12367 https://www.sciencedirect.com/science/article/abs/pii/s0143720804001202 https://www.sciencedirect.com/science/article/abs/pii/s0143720804001202 https://www.sciencedirect.com/science/article/abs/pii/s0143720804001202 https://www.sciencedirect.com/science/article/abs/pii/s0143720804001202 https://www.sciencedirect.com/science/article/abs/pii/s0143720804001202 https://www.sciencedirect.com/science/article/abs/pii/s0926337303005411 https://www.sciencedirect.com/science/article/abs/pii/s0926337303005411 https://www.sciencedirect.com/science/article/abs/pii/s0926337303005411 https://www.sciencedirect.com/science/article/abs/pii/s0926337303005411 http://www.thaiscience.info/journals/article/song/10462512.pdf http://www.thaiscience.info/journals/article/song/10462512.pdf http://www.thaiscience.info/journals/article/song/10462512.pdf http://www.thaiscience.info/journals/article/song/10462512.pdf https://www.sciencedirect.com/science/article/pii/s0032959202002911 https://www.sciencedirect.com/science/article/pii/s0032959202002911 https://www.sciencedirect.com/science/article/pii/s0032959202002911 https://www.sciencedirect.com/science/article/pii/s0032959202002911 https://www.mdpi.com/1420-3049/16/12/10370/htm https://www.mdpi.com/1420-3049/16/12/10370/htm https://www.mdpi.com/1420-3049/16/12/10370/htm https://www.mdpi.com/1420-3049/16/12/10370/htm https://www.mdpi.com/1420-3049/16/12/10370/htm https://www.sciencedirect.com/science/article/abs/pii/s1010603003000157 https://www.sciencedirect.com/science/article/abs/pii/s1010603003000157 https://www.sciencedirect.com/science/article/abs/pii/s1010603003000157 https://www.sciencedirect.com/science/article/abs/pii/s1010603003000157 https://www.sciencedirect.com/science/article/abs/pii/s1010603003000157 https://www.bookdepository.com/chemical-processes-marine-environments-antonio-gianguzza/9783642085895 https://www.bookdepository.com/chemical-processes-marine-environments-antonio-gianguzza/9783642085895 https://www.bookdepository.com/chemical-processes-marine-environments-antonio-gianguzza/9783642085895 https://pubs.acs.org/doi/abs/10.1021/es9905750 https://pubs.acs.org/doi/abs/10.1021/es9905750 https://pubs.acs.org/doi/abs/10.1021/es9905750 https://pubs.acs.org/doi/abs/10.1021/es9905750 https://www.sciencedirect.com/science/article/abs/pii/s0926337303004818 https://www.sciencedirect.com/science/article/abs/pii/s0926337303004818 https://www.sciencedirect.com/science/article/abs/pii/s0926337303004818 https://www.sciencedirect.com/science/article/abs/pii/s0926337303004818 https://www.sciencedirect.com/science/article/abs/pii/s0304389406002743 https://www.sciencedirect.com/science/article/abs/pii/s0304389406002743 https://www.sciencedirect.com/science/article/abs/pii/s0304389406002743 https://www.sciencedirect.com/science/article/abs/pii/s0304389406002743 https://www.sciencedirect.com/science/article/abs/pii/s0926337302000784 https://www.sciencedirect.com/science/article/abs/pii/s0926337302000784 https://www.sciencedirect.com/science/article/abs/pii/s0926337302000784 https://www.sciencedirect.com/science/article/abs/pii/s0926337302000784 https://www.sciencedirect.com/science/article/abs/pii/s0926337302000784 https://www.sciencedirect.com/science/article/abs/pii/s0926337302000784 https://s3.amazonaws.com/academia.edu.documents/11368176/removal_of_reactive_dyes_from_aqueous_solution_by_adsorption_on_coconut_coir_activated_carbon.pdf?response-content-disposition=inline%3b%20filename%3dremoval_of_reactive_dyes_from_aqueous_so.pdf&x-amz-algorithm=aws4-hmac-sha256&x-amz-credential=akiaiwowyygz2y53ul3a%2f20200319%2fus-east-1%2fs3%2faws4_request&x-amz-date=20200319t092235z&x-amz-expires=3600&x-amz-signedheaders=host&x-amz-signature=9b39ece2067eaa8ff7b3d9a656bbb8a83d7a56aa8506122cbf2ba47c5ed0ba6a 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https://s3.amazonaws.com/academia.edu.documents/11368176/removal_of_reactive_dyes_from_aqueous_solution_by_adsorption_on_coconut_coir_activated_carbon.pdf?response-content-disposition=inline%3b%20filename%3dremoval_of_reactive_dyes_from_aqueous_so.pdf&x-amz-algorithm=aws4-hmac-sha256&x-amz-credential=akiaiwowyygz2y53ul3a%2f20200319%2fus-east-1%2fs3%2faws4_request&x-amz-date=20200319t092235z&x-amz-expires=3600&x-amz-signedheaders=host&x-amz-signature=9b39ece2067eaa8ff7b3d9a656bbb8a83d7a56aa8506122cbf2ba47c5ed0ba6a https://s3.amazonaws.com/academia.edu.documents/11368176/removal_of_reactive_dyes_from_aqueous_solution_by_adsorption_on_coconut_coir_activated_carbon.pdf?response-content-disposition=inline%3b%20filename%3dremoval_of_reactive_dyes_from_aqueous_so.pdf&x-amz-algorithm=aws4-hmac-sha256&x-amz-credential=akiaiwowyygz2y53ul3a%2f20200319%2fus-east-1%2fs3%2faws4_request&x-amz-date=20200319t092235z&x-amz-expires=3600&x-amz-signedheaders=host&x-amz-signature=9b39ece2067eaa8ff7b3d9a656bbb8a83d7a56aa8506122cbf2ba47c5ed0ba6a https://s3.amazonaws.com/academia.edu.documents/11368176/removal_of_reactive_dyes_from_aqueous_solution_by_adsorption_on_coconut_coir_activated_carbon.pdf?response-content-disposition=inline%3b%20filename%3dremoval_of_reactive_dyes_from_aqueous_so.pdf&x-amz-algorithm=aws4-hmac-sha256&x-amz-credential=akiaiwowyygz2y53ul3a%2f20200319%2fus-east-1%2fs3%2faws4_request&x-amz-date=20200319t092235z&x-amz-expires=3600&x-amz-signedheaders=host&x-amz-signature=9b39ece2067eaa8ff7b3d9a656bbb8a83d7a56aa8506122cbf2ba47c5ed0ba6a https://doi.org/10.31699/ijcpe.2019.1.2 https://doi.org/10.31699/ijcpe.2019.1.2 https://doi.org/10.31699/ijcpe.2019.1.2 https://doi.org/10.31699/ijcpe.2019.1.2 n. a. mohammed, et al. / iraqi journal of chemical and petroleum engineering 21,1 (2020) 15 21 02 ازالة الصبغة الصفراء الفعالة من مياه المموثة المحضرة باستخدام تقنيو االكسدة المقدمة 2محمد سممان و 1عبير الورد, 1عبداالميرنور جامعة بغداد, كمية الهندسة, قسم الهندسة البيئية1 جامعة بغداد, مركز ابن سينا2 الخالصة في هذه الدراسة تم استخدام االشعة فوق البنفسجية الزالة الصبغة الصفراء الفعالة من مياه الصرف الصحي عممية( باستخدام aopبواسطة عممية االكسدة المتقدمة ) نانوميتر 424ذات الطول الموجي (tio2/uv/h2o2. ) وتم دراسة تاثير المتغيرات الرقم الهيدروجيني لممحمول وتركيز بيروكسيد الهيدروجين (ph و )و تركيز ثنائي اوكسيد التيتانيوم ) االبتدائي تركيز الصبغة(tio2 في مفاعل ذو الدفعة الواحدة عند . وقد تم 7و 3. ولوحظت أعمى معدالت إزالة المون في نطاق األس الهيدروجيني بين min 124الزمن فحص المستويات المثمى من بيروكسيد الالزمة لهذه العممية. يبدو أن المستويات العالية من بيروكسيد ينخفض مع زيادة تركيز الصبغة .كما اظهرت وكذلك عندما الهيدروجين يمكن أن تقمل من إزالة المون النتائج ان موديل التفاعل كان من الدرجة االولى. ة: الصبغة الصفراء الفعالة, ثنائي اوكسيد التيتانيوم, بيروكسيد الهيدروجين, عممية االكسدة المتقدمةالدالالكممات available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.20 no.4 (december 2019) 49 – 54 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: hussam jumaah mousa, email: jmhussam@gmail.com, name: hussein qasim hussein, email: husseinqassab@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. synthesis and characterization of nano y zeolite using mwcnt as media for crystal growth hussam jumaah mousa and hussein qasim hussein chemical engineering department, college of engineering, university of baghdad abstract the present research was conducted to synthesis y-zeolite by sol-gel technique using mwcnt (multiwalled carbon nanotubes) as crystallization medium to get a narrow range of particle size distribution with small average size compared with ordinary methods. the phase pattern, chemical structure, particle size, and surface area were detected by xrd, ftir, bet and afm, respectively. results shown that the average size of zeolite with and without using mwcnt were (92.39) nm and (55.17) nm respectively .particle size range reduced from (150-55) nm to (130-30) nm. the surface area enhanced to be (558) m 2 /g with slightly large pore volume (0.231) km 3 /g was obtained. meanwhile, degree of crystallization decreased to 120%. keywords: carbon nanotube, catalytic synthesis, nano y zeolite, mwcnt received on 21/01/2019, accepted on 25/02/2019, published on 30/12/1029 https://doi.org/10.31699/ijcpe.2019.4.8 1introduction zeolite is considered one of the most common types of adsorbent which can remove the mercaptan action and other sulphide from gasoline [1]. zeolite molecular sieves are crystalline microporous solids repleted with cavities and channels of molecular dimension between (3 to 10 a diameter)[1]. a classical definition of zeolite is a crystalline aluminosilicate with a three dimensionalframework structure that forms uniformly sized pores of moleculardimensions .y-type zeolites are among the most widely used zeolites in catalysis, especially for the conversion of hydrocarbons, give a structure with large poresallowing the adsorption of a large variety of molecules, but also a thermal stability and remarkable opportunity to perform multiple structural modifications according to thereaction conditions [2]. nano crystalline zeolite particles are becoming an important material in many technical applications (e.g. zeolite membranes). synthetic methods that minimize the zeolite crystal diameter, while providing a narrow particle size distribution, are of primary importance in these technical applications [3]. different methods have been proposed to synthesis a nano crystal zeolite such as the microwave method that produce nanoparticles with relatively narrower particle size distribution, requiring much shorter heating times and which did not significantly change composition or crystallinity. the zeolite crystals were in the range of 100−300 nm, compared with the conventional heating method [4]. another method is the synthesis of nano-zeolite from coal fly, the result was 400−500 nm in size [5]. a very reactive organic-template-free gel system is also used for the nano zeolite preparation crystals averaging about 400−500 nm in size [6]. the carbon nanotube is one of the materials that currently gathering the best properties mechanical, thermal and electronic [7]. these additions make it possible to be used in zeolite synthesis. multi-shell nanotubes have been used as media in co/y-zeolite catalysts support and the result was higher catalyst selectivity [8]. the aim of this research is to use the mwcnt as crystallization media in the synthesis of nano y zeolite catalyst with narrow range of particle size distribution, small average particle size and high texture properties. [sa .pv]. xrd, ftir, bet and afm will be measured to characterize the prepared catalyst. 2experimental work 2.1. feed stock and chemicals sodium aluminate was provided by kunshanyalong trading co., ltd china. sodium aluminate have molecular weight of 62 g/g mole , purity % =5056(al2o3), 40-45 (na2o).sodium silicate used in the synthesis of zeolite was provided by sigma aldrich. chemical formula na2sio3, have a molecular weight of 122g/g mo', purity % =10.63 na2o, 26.5 sio2. sodium hydroxide used in the synthesis of zeolite was provided by sigma aldrich. chemical formula naoh, have a molecular weight of 40 g/g mole, purity % =99.5. ammonium chloride used in the synthesis of zeolite was provided by merck. https://doi.org/10.31699/ijcpe.2019.4.8 h. j. mousa and h. q. hussein / iraqi journal of chemical and petroleum engineering 20,4 (2019) 49 54 05 the multiwall carbon nanotubes (mwcnt) used in the experiment was made by zhengzhou dongyao materials company. the purity was 97 % and the surface area 231.856 m 2 /g. 2.2. synthesis of nano y zeolite the sol-gel and hydrothermal method was applied for synthesis of nay zeolite .the aging solution was prepared from 4.07 g sodium hydroxide pellets dissolved in 19.95 g of demineralized water. 2.09 g of the sodium aluminate solution is stirred in 100ml plastic bottle until dissolution, then 33g of sodium silicate was added and aging for 24 h. the stock solution was 131 g of deionized water was added to 0.14 sodium hydroxide with 13.1 g sodium aluminate and 1 g mwcnt, the mixture was stirred then 206 g of sodium silicate was added and the mixture was mixed with 1600 rpm mixer for 20 min. the solutions prepared in the previous steps were mixed in poly propylene bottle and subjected to a homogenization for 24h at room temperature; the products were centrifuged for 15 min for mwcnt separation and then the mwcnt was transferred to jacketed stainless steel autoclaves for crystallization. the autoclave was made from stainless steel, and lined with polytetraflorouethylene (ptfe). as shown in fig. 1.the mixture was heated at 100 ° c for 24 hours without agitation. the product was then filtered, washed with distilled water until neutralization (ph = 7) and then dried in an oven at 110 ° c for 24 hours. calcination was also carried at 550 cfor 3 hours. fig. 1. design of the autoclave lined with ptfe 2.3 characterizations of nano y zeolite a. x-ray diffraction (xrd) the model of the x-ray diffractor meter (shimazoxrd 6000) was located university of baghdad college of education ibn al-haytham. the x-ray diffractometer was used to detect the phase of the nano y zeolite. b. scanning electron microscope (sem) the electron microscope uses a stream of election rays to produce high magnification resolution. the instrument located in the minster of science and technology. c. bet surface analyzer test method according to astm d1993 for bet surface area and pore volume. ministry of oil, research and development oil center. d. atomic force microscope the instrument used was (aa3000-scanning probe microscope, angstrom advance inc.) located in college of science, department of chemistry, university of baghdad. e. measure sulfur concentration astm d7039 the sulfur concentration was measured using the astm d7039 method by the sindie otg sulfur analyzer. the device located in ministry of oil,research and development oil center, bob al sham. f. fourier-transform infrared spectroscopy (ftir) the instrument is used to obtain an infrared spectrum of emission of the prepared zeolite and its located in the minster of science and technology. 3results and discussion 3.1. x ray diffraction fig. 2 shows the x-ray diffraction of the sample. this spectrum shows the characteristic diffraction peaks of a na-y zeolite, as are presented in the collection of simulated powder diagrams for zeolites .these peaks are intense, thin and no additional peaks are detected. table 1 shows the comparison of angle 2ɵ and d spacing between the sample and the standard zeolite. both data listed in the table are close and represent the dominant peaks of the measurement. all the peaks of diffraction were indexed in the cubic system. the mesh parameter determined atfrom the structural refinement is a = 24.678 å. xrd analyses were carried out at room temperature using cukα radiation nickel filter (λ= 1.5418a) and energy condition of (4 kv and 3 ma) zeolite y h. j. mousa and h. q. hussein / iraqi journal of chemical and petroleum engineering 20,4 (2019) 49 54 05 zeolite y with mwcnt fig. 2. xrd pattern for zeolite y with and without the using of mwcnt from the figure 2it can be seen that the using of the mwcnt gives the same peaks but with different intensities. this mean that no change has occurred on the crystal structure of the zeolite y .the change occur on the peak intensities which mean that the degree of crystallization and the average crystal size has changed. table 1. comparison of spacing and angle, between prepared catalyst with mwcnts and standard prepared catalyst standard of catalyst angle (2theta)deg d, spacing(å) angle (2theta) deg d, spacing(å) 7.202 12.402 7.18 12.41 10.105 9.205 10.172 9.210 16.120 5.501 16.103 5.503 21.862 3.881 21.901 3.890 23.380 3.721 23.532 3.701 27.201 3.284 27.251 3.279 32.014 2.824 32.120 2.830 the relative crystallinity was determined by dividing the sum of the peak intensities of the prepared zeolite at each stage according to equation 1 [10]. relative crystallinity = x 100 (1) the degree of crystallinity without mwcnt was 144.84 % and has decreased to 120 % with mwcnt. the decrease of the degree of crystallinity was due to the effect of mwcnt as crystallization medium. the diffraction peaks of nano sized zeolites shows a decrease in crystallinity and crystal size, which can be described to the occurrence of extinction effects caused by the coexistence of particles with smaller sizes in the sample [11]. 3.2. scanning electron microscopy (sem) the sem image provides information on the morphology of the crystals. fig. 3 shows that the crystalline image of the synthesized zeolite has small average size because of nano sized particles as compared with that shown in literature revealing a uniform particle size with regular shape and uniform particle size distribution [12] fig. 3. sem images of the prepared zeolite with different scales 3.3. atomic force microscope (afm) the topography of the surface of the prepared zeolite was taken by the atomic force microscope. these images show details about particle size distribution. afm allowed a detailed observation of nanometer-size scale at crystal surfaces. the effect of using the mwcnt on the average particle size of the prepared zeolite was shown in fig. 4 and fig. 5. h. j. mousa and h. q. hussein / iraqi journal of chemical and petroleum engineering 20,4 (2019) 49 54 05 fig. 4. afm particle size distribution with average diameter with and without mwcnt fig. 5. afm particle size distribution with average diameter with mwcnt the average diameter of particle as shown by the afm was reduced from 92.3 nm to 55.17 nm, also the particle size distribution has shifted toward a lower particle size range. the differences in particle sizes with and without of the mwcnt was due to the small diameter of the mwcnt which acts as a nucleation point.zeolite single crystal is grown around the carbon nanotubes. it is essential that nucleation of the zeolite takes place exclusively between the carbon nanotubes [13]. 3.4. surface area and pore volume the surface area and pore volume have been measured for prepared y-zeolite with and without of mwcnt. the surface area of the zeolite without mwcnt was 480 m 2 /g and the pore volume was 0.22 cm 3 / while with mwcnt the surface area increase to 558 m 2 /g and the pore volume slightly increased to 0.231 cm 3 /g. the increase of the surface area of the zeolite with mwcnt is due to the nucleation of the zeolite takes place on the carbon nanotubes which make the crystal size smaller [13]. 3.5. fourier transform infrared spectroscopy analysis the study of zeolite after the addition of mwcnt by infrared spectroscopy ftir aims to determine the different chemical functions present on the surface of these solids. it is a complementary technique that focuses in general on the study of samples at the molecular level. the ftir image is shown in figure 6. the regions are found which characterized the faujasite structure are explained as the bands that appears in the region between 3365-3489 cm -1 reveal to the oh stretching band also called low frequency band, sio4 molecules and al-oh. the bands in the range of 10101019 cm -1 indicate the presence of si-o. absorption at about 443 -465 cm -1 was assigned to si – o – al stretching where al in the octahedral coordination and fig. 6 show the vibration of si-al groups. from above it was concluded that the ftir spectra of the synthesis zeolite is matched with the typical absorption peaks of commercial one [12]. h. j. mousa and h. q. hussein / iraqi journal of chemical and petroleum engineering 20,4 (2019) 49 54 05 fig. 6. ftir analysis of(a) zeolite modified with mwcnt , (b) y zeolite without mwcnt 4conclusions the phases identification of the formed zeolite shows well-formed crystals having a cubo-octahedral form characteristic of a faujasite type zeolite. the surface area of the zeolite before addition was 480 m 2 /g and the pore volume was 0.22 cm 3 /g. after the addition of the mwcnt the surface area increases to 558 m 2 /g and the pore volume increase slightly with value of 0.231 cm 3 /g. the addition of mwcnt while preparing the zeolite y did not have an effect on the crystal structure of the zeolite and the resulting zeolite is still type y but with different degree of crystallization and average particle size were the degree of crystillinity reduced from 144.84 to 120% .also the average particle size was reduced from 92.39 to 55.17nm. nomenclature bet=brunauar , emmett, teller sem=scanning electron microscopy mwcnt =multi wall carbon nano tube xrd=x-ray diffraction references [1] zeng y., jushengui,* xing weihong and chen changlin, 2008 ," adsorption of mercaptan from model gasoline on 13x loaded with zn2+", the canadian journal of chemical engineering, 86,186187. [2] mirfendereski, mojtaba, and toraj mohammadi. "effects of synthesis parameters on the characteristics of naa type zeolite nanoparticles." proceedings of the world congress on recent advances in nanotechnology (ran’16). 2016. [3] severance, michael a. nanocrystalline zeolites: synthesis, mechanism, and applications. diss. the ohio state university, 2014. [4] ansari, m., aroujalian, a., raisi, a., dabir, b. and fathizadeh, m., 2014. preparation and characterization of nano-nax zeolite by microwave assisted hydrothermal method. advanced powder technology, 25(2), pp.722-727. [5] chen, x., wendell, k., zhu, j., li, j., yu, x. and zhang, z., 2012. synthesis of nano-zeolite from coal fly ash and its potential for nutrient sequestration from anaerobically digested swine wastewater. bioresource technology, 110, pp.79-85. [6] valtchev, v.p., tosheva, l. and bozhilov, k.n., 2005. synthesis of zeolite nanocrystals at room temperature. langmuir, 21(23), pp.10724-10729. [7] lee, n. s., et al. "application of carbon nanotubes to field emission displays." diamond and related materials 10.2 (2001): 265-270. [8] fonseca, a., hernadi, k., piedigrosso, p., colomer, j.f., mukhopadhyay, k., doome, r., lazarescu, s., biro, l.p., lambin, p., thiry, p.a. and bernaerts, d., 1998. synthesis of single-and multi-wall carbon nanotubes over supported catalysts. applied physics a, 67(1), pp.11-22. [9] c. baerlocher, meier, l.b. mccusker, d.h. olson, “atlas of zeolite framework types”,6th edition, elsevier, amsterdam (2007). [10] treacy m.m.j. and higgins j.b., 2001, “collection of simulated xrd powder patterns for zeolites”, 4th edition amsterdam: elsevier, [11] zhang, w., bao, x., guo, x., and wang, x. (1999). a high-resolution solid-state nmr study on nanostructured hzsm-5 zeolite. catal. lett. 60:89–94. [12] ban and nada s., 2016. abdaulrahman catalytic reforming of naphtha using novel prepared pt-ti / hy zeolite chemical engineering department thesis [13] iver schmidt, i., boisen, a., gustavsson, e., ståhl, k., pehrson, s., dahl, s., carlsson, a. and jacobsen, c.j., 2001. carbon nanotube templated growth of mesoporous zeolite single crystals. chemistry of materials, 13(12), pp.4416-4418. https://onlinelibrary.wiley.com/doi/abs/10.1002/cjce.20019 https://onlinelibrary.wiley.com/doi/abs/10.1002/cjce.20019 https://onlinelibrary.wiley.com/doi/abs/10.1002/cjce.20019 https://onlinelibrary.wiley.com/doi/abs/10.1002/cjce.20019 https://onlinelibrary.wiley.com/doi/abs/10.1002/cjce.20019 https://avestia.com/ran2016_proceedings/files/paper/icnnfc/113.pdf https://avestia.com/ran2016_proceedings/files/paper/icnnfc/113.pdf https://avestia.com/ran2016_proceedings/files/paper/icnnfc/113.pdf https://avestia.com/ran2016_proceedings/files/paper/icnnfc/113.pdf https://avestia.com/ran2016_proceedings/files/paper/icnnfc/113.pdf https://avestia.com/ran2016_proceedings/files/paper/icnnfc/113.pdf https://etd.ohiolink.edu/pg_10?0::no:10:p10_accession_num:osu1387817713 https://etd.ohiolink.edu/pg_10?0::no:10:p10_accession_num:osu1387817713 https://etd.ohiolink.edu/pg_10?0::no:10:p10_accession_num:osu1387817713 https://www.sciencedirect.com/science/article/pii/s0921883113002227 https://www.sciencedirect.com/science/article/pii/s0921883113002227 https://www.sciencedirect.com/science/article/pii/s0921883113002227 https://www.sciencedirect.com/science/article/pii/s0921883113002227 https://www.sciencedirect.com/science/article/pii/s0921883113002227 https://www.sciencedirect.com/science/article/pii/s0960852412001204 https://www.sciencedirect.com/science/article/pii/s0960852412001204 https://www.sciencedirect.com/science/article/pii/s0960852412001204 https://www.sciencedirect.com/science/article/pii/s0960852412001204 https://www.sciencedirect.com/science/article/pii/s0960852412001204 https://pubs.acs.org/doi/abs/10.1021/la050323e https://pubs.acs.org/doi/abs/10.1021/la050323e https://pubs.acs.org/doi/abs/10.1021/la050323e https://www.sciencedirect.com/science/article/abs/pii/s0925963500004787 https://www.sciencedirect.com/science/article/abs/pii/s0925963500004787 https://www.sciencedirect.com/science/article/abs/pii/s0925963500004787 https://link.springer.com/article/10.1007/s003390050732 https://link.springer.com/article/10.1007/s003390050732 https://link.springer.com/article/10.1007/s003390050732 https://link.springer.com/article/10.1007/s003390050732 https://link.springer.com/article/10.1007/s003390050732 https://link.springer.com/article/10.1007/s003390050732 https://books.google.iq/books?hl=en&lr=&id=66z0m59omwcc&oi=fnd&pg=pp1&dq=%5b9%5d%09c.+baerlocher,+meier,+l.b.+mccusker,+d.h.+olson,+%e2%80%9catlas+of+zeolite+framework+types%e2%80%9d,6th+edition,+elsevier,+amsterdam+(2007).&ots=rpnwgzg9ra&sig=ss4qteyb2mg0_3mr0ms45h4me3a&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=66z0m59omwcc&oi=fnd&pg=pp1&dq=%5b9%5d%09c.+baerlocher,+meier,+l.b.+mccusker,+d.h.+olson,+%e2%80%9catlas+of+zeolite+framework+types%e2%80%9d,6th+edition,+elsevier,+amsterdam+(2007).&ots=rpnwgzg9ra&sig=ss4qteyb2mg0_3mr0ms45h4me3a&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=66z0m59omwcc&oi=fnd&pg=pp1&dq=%5b9%5d%09c.+baerlocher,+meier,+l.b.+mccusker,+d.h.+olson,+%e2%80%9catlas+of+zeolite+framework+types%e2%80%9d,6th+edition,+elsevier,+amsterdam+(2007).&ots=rpnwgzg9ra&sig=ss4qteyb2mg0_3mr0ms45h4me3a&redir_esc=y#v=onepage&q&f=false http://www.iza-structure.org/books/collection_4ed.pdf http://www.iza-structure.org/books/collection_4ed.pdf http://www.iza-structure.org/books/collection_4ed.pdf https://link.springer.com/article/10.1023/a:1019061714047 https://link.springer.com/article/10.1023/a:1019061714047 https://link.springer.com/article/10.1023/a:1019061714047 https://www.researchgate.net/publication/309375145_catalytic_reforming_of_iraqi_naphtha_over_pt-ti_hy_zeolite_catalyst https://www.researchgate.net/publication/309375145_catalytic_reforming_of_iraqi_naphtha_over_pt-ti_hy_zeolite_catalyst https://www.researchgate.net/publication/309375145_catalytic_reforming_of_iraqi_naphtha_over_pt-ti_hy_zeolite_catalyst https://pubs.acs.org/doi/abs/10.1021/cm011206h https://pubs.acs.org/doi/abs/10.1021/cm011206h https://pubs.acs.org/doi/abs/10.1021/cm011206h https://pubs.acs.org/doi/abs/10.1021/cm011206h https://pubs.acs.org/doi/abs/10.1021/cm011206h h. j. mousa and h. q. hussein / iraqi journal of chemical and petroleum engineering 20,4 (2019) 49 54 05 كوسائل لمنمو البموري mwcntباستخدام y توليف وتوصيف زيوليت نانو و حسين قاسم حسين حسام موسى جمعه جامعةبغداد كميةالهندسة، الهندسة الكيمياوية، قسم الخالصة كوسيط تبمور لمحصول mwcntباستخدام sol-gelبتقنية y-zeoliteتم إجراء البحث الحالي لمتوليف نمط عن الكشف تم. العادية بالطرق مقارنة صغير حجمعمى نطاق ضيق لتوزيع حجم الجسيمات مع متوسط عمى bgtوafmو ftirو xrd بواسطة السطح ومساحة الجسيمات وحجم الكيميائية والبنية الطور ( نانومتر 92.39كان ) mwcntدقائق الزيوليت مع وبدون استخدام حجمالتوالي. أظهرت النتائج أن متوسط ( 11.15( نانومتر إلى )92.39( نانومتر عمى التوالي وانخفض حجم حجم الجسيمات من )11.15و ) / 3( م 0.231/ جم مع حجم مسامي كبير قمياًل ) 2( م 115نانومتر. تم تحسين مساحة السطح لتصبح ) ٪. 120نخفضت درجة التبمور إلى جم. وفي الوقت نفسه ، ا y ،mwcntالكممات المفتاحية: األنبوب النانوي الكربوني ، التوليف الحفزي ، زيوليت نانو available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.21 no.1 (march 2020) 45 – 52 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: laith warid farhan , email: laith.wared@gmail.com , name: faleh h. m. almahdawi , email: fhmetr@yahoo.com , name: adel sherif hammadi, email: 80013@uotechnology.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. dissolving precipitated asphaltenes inside oil reservoirs using local solvents laith warid farhan a ,faleh h. m. almahdawi a and adel sherif hammadi b a petroleum engineering department/ college of engineering/ university of baghdad, iraq b petroleum technology department/university of technology, iraq abstract there are several oil reservoirs that had severe from a sudden or gradual decline in their production due to asphaltene precipitation inside these reservoirs. asphaltene deposition inside oil reservoirs causes damage for permeability and skin factor, wettability alteration of a reservoir, greater drawdown pressure. these adverse changing lead to flow rate reduction, so the economic profit will drop. the aim of this study is using local solvents: reformate, heavy-naphtha and binary of them for dissolving precipitated asphaltene inside the oil reservoir. three samples of the sand pack had been prepared and mixed with a certain amount of asphaltene. permeability of these samples calculated before and after mixed with asphaltenes. then, the permeability of samples calculated after solvents injection into that porous media. after that, all the values of samples permeability converted to average permeability damage compared with the pure samples. the results show the average permeability damage of samples that mixed with 20 gm was 24 %, but after reformate injected reduced to 14 %. after injected heavy naphtha to porous media, the average permeability reduced only to 17%. the binary solvent had been prepared from reformatted mixed with heavy naphtha gained the best results because it dropped the average permeability damage to 10%. keywords: asphaltene deposition, iraqi local solvents, permeability damage, oil reservoirs, reformates heavy naphtha. received on 04/09/2019, accepted on 01/11/2019, published on 30/03/0220 https://doi.org/10.31699/ijcpe.2020.1.7 1introduction this decrease in permeability within the reservoir is called formation damage. there are many types of formation damage that are mainly divided into organically produced by chemical reactions between the rock and fluids or fluids among them, either the second type is mechanical which arises due to production or drilling operations due to force and movement‎[1]. there are many ways to increase permeability, including acidizing of the layer by injecting organic acids such as hydrochloric acid (hcl) and hydrofluoric acid (hf) into the layer for scrubbing pore surfaces and thus increase permeability. another method is hydraulic fracturing, which is done through high-pressure liquid injection to reservoir formation and as a result, the permeability increases ‎[2]. one of the serious damage cases is the deposition of asphaltenes inside the reservoir that generate organic damage to permeability. asphaltenes deposition probably occurs inside the reservoir or inside the production pipes or in the surface facilities. for the purpose of removing the asphaltenes inside the reservoir, a solvent such as toluene or benzene is injected for dissolving it in the pores and thus restore the unaffected permeability ‎[3]. it is worth noting that the problem of asphaltenes is a global problem that occurs in both light and heavy oil reservoirs. this problem has caused a huge economic loss because it is working to significantly reduce oil production. many of the iraqi fields suffer from this issue, as happens in the bazargan field and the east baghdad field. the main reason for the possible deposition of asphaltene is the chemical composition of the oil. so to know the stability of asphaltene in crude oil must know the compounds of crude oil. the percentage of saturated, resin, aromatic and asphaltene compounds that presence in the crude oil then analyzed these compounds by a process called sara analysis. oil components either measure by astm test or by nuclear magnetic resonance (nmr). crude oil components: saturates, resins, aromatics, and asphaltenes can be predicted by nuclear magnetic resonance by measuring aromatic hydrogen and aromatic carbon for crude oil. sara analysis is an analytical method for the crude oil components by which the stability of the asphaltene is revealed. this method includes calculating the values of certain variables and these variables reflect the stability of crude oil ‎[4], ‎[5]. four types of damage are caused by the formation of asphaltenes inside the porous media ‎[6]:  reduce permeability.  change of wettability.  the decrease in viscosity of crude oil.  formation of water emulsions in oil. https://doi.org/10.31699/ijcpe.2020.1.7 l. w. farhan et. al. / iraqi journal of chemical and petroleum engineering 21,1 (2020) 45 52 64 1.1. permeability measurements permeability is the property of the porous medium that dealing with the capacity and capability of the formation to conduct fluids flow. it director directional movement and flow rate of fluid flow ‎[7]. darcy developed equation represented the fluid flow through a porous medium and it became one of the most popular equations in reservoir engineering. this equation found in many forms, one of them the following formula for horizontal linear incompressible flow through a porous medium ‎[8]: (1) q = flow rate, cm/s. k = permeability, darcy. a = cross-sectional area, cm 2 . µ = viscosity, (cp) l = length of core sample, cm. ∆p = pressure drop, atm. there are many assumptions to the above equation includes ‎[8]:  the direction of flow is horizontal.  the regime of flow is laminar.  there is a fluid in a porous medium.  between rock and fluid should not be a chemical process. reservoir rock with a high value of permeability leads to produce a large amount of commercial oil and gas for a long period. in contrast, reservoir rock with low permeability may not able to produce a large quantity of oil and gas. because one darcy is a very high value for reservoir rock, millidarcy is a more common unit in permeability calculation ‎[7]. worthwhile, the relationship between core and well log data was determined by artificial neural network (ann) in cored wells to develop the predictive model and then was used to develop the flow unit prediction to un-cored wells ‎[9]. there are factors affecting permeability values ‎[10]:  shape and size of sand grain: rock with small flat grains has less permeability from the rock with the large rounded grain.  lamination: rock with shale lamination has less permeability than layers without lamination.  cementation: porosity and permeability affected by the type and position of cementation within the rock. the permeability of rock describe according to table 1: table 1. description of permeability values ‎[11] permeability range, md permeability description poor fair moderate good very good there are too many sources of permeability data include ‎[12]:  core sample laboratory measurement.  nuclear magnetic response (nmr).  drill stem test and other well pressure tests.  well logging with indirect methods.  correlations that attempt to forecast permeability from porosity values.  geostatistical techniques attempt to predict permeability with spatial variation. 2experimental work 2.1. materials a. crude oil the physical oil properties of crude oil from tannumah illustrated in table 2 after provided from midland oil company table 2. physical oil properties of a sample property value specific gravity 0.922 api gravity 22 viscosity at 37 c, cp 31 saturate compounds, % wt. 42.3 aromatic compounds, % wt. 26.7 resin compounds, % wt. 18.2 asphaltene compounds, % wt. 12.8 b. toluene according to (hsdb, 1991) “toluene is a combustible, colorless, anticorrosive fluid as the same as benzene odor". it is unsolvable in water and solvable in acetone, absolute alcohol, ether, chloroform, benzene, petroleum ether, glacial acetic acid, and carbon disulfide)”. toluene's molecular formula is c7h8. c. hexane the n-hexane used in these experiments had been gotten from al-dura refinery. hexane represents a precipitant liquid for asphaltene. it used to illustrate the effect of solvent in reduced asphaltene deposition. the molecular formula of hexane is c6h14. d. reformate reformate is a solvent liquid for asphaltenes. reformate had been gotten from al-dura refinery. the properties of reformate that used in this study shown in table 3. l. w. farhan et. al. / iraqi journal of chemical and petroleum engineering 21,1 (2020) 45 52 64 table 3. properties of reformate api 61.7 specific gravity at 60f°/60 f° 0.733 sulfur content 3 ppm astm distillation the distillate,vol% boiling point(c°) 60 88 94 106 110 117 124 132 140 147 178 ibp 10 20 30 40 50 60 70 80 90 fb e. heavy naphtha heavy naphtha is a solvent liquid for asphaltenes. reformate had been gotten from al-dura refinery. the properties of reformate that used in this study shown in table 4. table 4. properties of heavy naphtha api 54.9 specific gravity at 60f°/60 f° 0.759 boiling range(c°) (90 – 180) c btx content, vol % benzene toluene p and m xylene o-xylene 3.18 14.94 17.66 11.58 astm distillation the distillate,vol% boiling point(c°) 43 71 80 86 92 97 103 110 121 144 154 180 ibp 10 20 30 40 50 60 70 80 90 95 fb nanotechnology has shown a lot of promise in the oil and gas sectors, including nanoparticle-based drilling fluids ‎[13]. so, the nano surfactant materials recommended for use. 2.2. sand sand has been used to make the sand packing with magnitude scattering of 80 to 500 µm. 2.3 fluid injection system all the experiments related to testing flow rate and pressure through the core sample needed to the fluid injection system. the accuracy of that system is too sensitive. so, the price of an accurate system reaches to 500,000$. this study building on a simple system consists of the reservoir tank, core holder, water bath and co2 bottle. a. reservoir tank and accessories a container tank has been made from the carbon steel layer (5 mm thickness) inorder to resist high pressures. all the joints tools manufactured from tungsten so as to bear the high pressures. that apparatus holds two orifices, the first on the roof of the container with a gate valve (inlet) to fill up the tank by either oil, water or solvents, the other passageway to transfer the fluids to the core holder. b. core holder core holder is composed of a high-pressure tube that has 1.5 " an internal diameter. it connects with the container tank from side and tape from the other side. as well it is made up of a pipe that has an external diameter of 1.5" (38 mm) and an internal diameter of ( 30 mm). it manufactured of anti-corrosion stainless steel to prevent corrosion error. besides, it provided with very fine filter bond inner the pipe to stop of sand pack movement or sand grains along the pipes. c. co2 bottle a co2 2000 psi bottle has been used through the experiments to move fluids into the sand pack d. check valve the check valve has been used to push the fluid forward only and pressurized the contained fluid. e. heater used for heating the injected fluids through the system. it put on the route vessel. that vessel bearing a high boiling point has been placed over this heater. f. pressure differential gauge used for measuring the pressure drop along with the sand pack with upper limit reading 3000 psi. g. thermometer a thermometer is a tool that measures temperature or a temperature gradient. the fluid injection system and its part illustrated in fig. 1, fig. 2 and fig. 3. l. w. farhan et. al. / iraqi journal of chemical and petroleum engineering 21,1 (2020) 45 52 64 fig. 1. fluid injection system design fig. 2. fluid injection system fig. 3. core holder of the fluid injection system 2.4. the procedure of the fluid injection experiment a. the preparation of sand pack sand granules with sizes between 80 and 500 are washed and dried. in some cases the sand mixed with a certain weight from asphaltene to reduce permeability and shown the effect of asphaltene on permeability calculations, then placed inside the tube ends with a filter from both sides to prevent sand leaking out and allowing the fluid to pass into and out of the tube. b. the preparation of injected fluid the crude oil with or without solvents were injected to sand pack for showing the permeability changes that occurred due to the presence of solvents. the stirrer device has been used to make homogenously mixed fluid. c. permeability measurements using darcy’s law, the permeability of the sand pack in different cases has been calculated. the equation of darcy’s law shown below: (1) q = flow rate, cm/s. k = permeability, darcy. a = cross-sectional area, cm 2 . µ = viscosity, (cp) l = length of core sample, cm. ∆p = pressure drop, atm. the constants of darcy’s law-related with this study shown in table 5. table 5. darcy’s equation input parameter value unit cross sectional area 7.068 cm 2 length of the core holder 10 cm viscosity of water 1 cp viscosity of oil 31 cp the viscosity of the oil-reformate mixture 28.34 cp the viscosity of oilheavy naphtha mixture 26.61 cp the viscosity of oilreformate-heavy naphtha mixture 27.21 cp 3results and discussion 3.1. 3.1. permeability of sand packs in different cases 2.0. asphaltenes represent the cholesterol of petroleum engineering because it blocks the passageway of movable oil. it adversely affects the permeability property of rocks, no doubt lead to production reduction. to illustrate the effect of asphaltene and solvents that injection for asphaltene dissolving must measure the original permeability, the damaged permeability, and the recovered permeability. the study depends on eleven different cases for the illustration of its goal. l. w. farhan et. al. / iraqi journal of chemical and petroleum engineering 21,1 (2020) 45 52 64 these cases are shown in table 6. in each case, the sand pack fully saturated with injection liquid for 1 hour for precipitant or dissolve asphaltene then reinjection the same liquid for permeability measurement purposes. table 6. cases of permeability measurements case number rock state injection fluids 1 sands water 2 sand + 20 gm asphaltene oil 3 sand + 20 gm asphaltene crude oil 80 % + nhexane 20 % 4 sand + 20 gm asphaltene crude oil 80%+ reformate 20 % 5 sand + 20 gm asphaltene crude oil 80 % + heavy naphtha 20 % 6 sand + 20 gm asphaltene crude oil 80 % + heavy naphtha 10 % + reformate 10 % a. case 1 using the injection system, the permeability of three pure sand packs calculated. pressing crude oil that presence in container tank by co2 bottle stimulates the oil to enter the core holder. measure the pressure in inlet and outlet give differential pressure. measure the volume and time given flow rate. the results are shown in table 7. the difference in permeability between three sand pack samples belongs to the difference in flow rate and pressure drop. the last difference result from the unlike composite of each simple table 7. permeability calculations of case 1 sample v t q ∆p k no. cm 3 sec. cm 3 / sec. (cm cp)/sec. atm. atm./cm darcy 1 33.2 10 3.32 0.47 4.2 0.42 1.123 2 33.8 10 3.39 0.48 4.7 0.47 1.027 3 32.5 10 3.25 0.46 5.2 0.52 0.89 b. case 2 to illustrate the effect of asphaltene precipitated on permeability, the sand pack sample mixed with 20 gm of dry asphalt. the results are shown in table 8. the average permeability damage was 24 % that means a quarter of well production performance declined. it calculated from this equation: ( ) ∑ ( ) ( ) ∑ ( ) (2) table 8. permeability calculations of case 2 sample v t q ∆p k no. cm 3 sec. cm 3 / sec. (cm cp)/sec. atm. atm./cm darcy 1 16 60 0.27 1.18 13.6 1.36 0.868 2 16 60 0.27 1.18 15.5 1.55 0.764 3 15 60 0.25 1.09 16.8 1.68 0.651 c. case 3 to illustrate the effect of n-hexane (precipitant) on crude oil, case 4 includes mixed 80 % crude oil and 20 % n-hexane. also, sand packs mixed with 20 gm dry asphaltene. the results are shown in the 9 with 48% average permeability reduction. that means almost half of the production performance dropped. table 9. permeability calculations of case 3 sample v t q ∆p k no. cm 3 sec. cm 3 / sec. (cm cp)/sec. atm. atm./cm darcy 1 15 60 0.25 1.09 17.1 1.71 0.64 2 12.5 60 0.2 0.87 17.5 1.75 0.5 3 12.5 60 0.2 0.87 20 2 0.437 d. case 4 sand pack mixed with 20 gm of dry asphalt. also crude oil in this case mixed with reformates solvent (80 % wt. crude oil + 20 % wt. solvent). the results are shown in table 10. the average production damage was 14 %. that means only 14 %of production performance declined, while in case two was 24 % that similar to this case apart from fluids there is only crude oil without solvent. table 10. permeability calculations of case 4 sample v t q ∆p k no. cm 3 sec. cm 3 / sec. (cm cp)/sec. atm. atm./cm darcy 1 10.8 60 0.18 0.74 8.2 0.82 0.901 2 11.4 60 0.19 0.78 9 0.9 0.873 3 12 60 0.2 0.79 9.5 0.95 0.832 e. case 5 another solvent used to remove the asphaltene particle is heavy naphtha. in this case, mixed of 80 % crude and 20 %, heavy naphtha injected to sand packs mixed with 20 gm of dry asphalt. the results of this experiment were shown in table 11. the average permeability damage was 17 %. that means only 17 % of production performance declined, l. w. farhan et. al. / iraqi journal of chemical and petroleum engineering 21,1 (2020) 45 52 05 while in case two was 24 % that similar to this case excluding for fluids, there is only crude oil without solvent. table 11. permeability calculations of case 5 sample v t q ∆p k no. cm 3 sec. cm 3 / sec. (cm cp)/sec. atm. atm./cm darcy 1 11.1 60 0.185 0.7 8.3 0.83 0.844 2 12 60 0.2 0.75 8.9 0.89 0.844 3 12 60 0.2 0.79 9.7 0.97 0.818 f. case 6 binary solvent from 10 % heavy naphtha and 10 % reformate was prepared and mixed with 80 % crude oil. sand packs also mixed with 20 gm dry asphalt. the results of these experiments were shown in table 12. the average permeability damage was 10 %. that means only 10 % of production performance dropped, whereas, in situation two was 24 % that similar to this situation with the exception of fluids, there is only crude oil without solvent. table 12. permeability calculations of case 6 sample v t q ∆p k no. cm 3 sec. cm 3 / sec. (cm cp)/sec. atm. atm./cm darcy 1 10.8 60 0.18 0.68 7.2 0.72 0.948 2 12 60 0.2 0.78 8.5 0.85 0.917 3 12 60 0.2 0.78 9 0.9 0.872 3.2. average permeability damage after measure permeability damage in each case compares it with initial permeability using the equation. the higher average permeability damage means higher production performance damage. the results are shown in table 13 and in fig. 4. table 13. summary of average permeability damage case average permeability damage no. % 2 24 4 48 6 14 8 17 10 10 fig. 4. summary of average permeability damage from figure these points are observed:  the first five values represent the higher permeability damage due to the absence of the solvents within the sand packs.  presence n-hexane in 4 and 5 cases gave more average permeability damage than other cases due to the precipitant characteristics of n-hexane.  the effectiveness of the solvents used in the study in preventing and dissolving the asphaltenes according to the preference as follows: (3) 4conclusions a. solvent quality order in preventing the deposition of the asphaltenes, respectively: binary of reformateheavy naphtha, then reformate, the less profitable was heavy naphtha. b. solvents have a great influence to reduce average permeability damage. solvents dissolve the asphaltene that leads to minimizing the advertising effect of asphaltenes. recommendation a. using real cores and plugs damaged with asphaltenes instead of using the sand pack. the cores and plugs prefer to be different types of reservoir rock such as sandstone and limestone. b. working an economical model for real field case for knowing the optimization quantity and types of solvent required for injection. c. working on an accurate fluid injection system from a global company consists of digital meters and a piston pump. acknowledgments i would like to thank my supervisor assist prof. dr. faleh h. m. almahdawi for his kindness and forgiveness in a critical stage in this study. furthermore, all his care and advice contributed to all the good work in this study. 0 20 40 60 1 2 3 4 5 a ve ra g e p e rm e a b il it y d a m a g e ,% case number average permeability damage l. w. farhan et. al. / iraqi journal of chemical and petroleum engineering 21,1 (2020) 45 52 05 nomenclature ∆p pressure drop, atm. µ viscosity, (cp) a cross-sectional area, cm 2 . astm american society for testing and materials btx benzene, toluene and xylene hcl hydrochloric hf hydrofluoric k permeability, darcy. l length of the core sample, cm. q flow rate, cm/s. references [1] donnez, pierre. essentials of reservoir engineering. vol. 2. editions technip, 2012. [2] guo, boyun. petroleum production engineering, a computer-assisted approach. elsevier, 2011. [3] jg speight the chemistry and technology of petroleum. crc press, 2014. [4] sanchez-minero, felipe, et al. "predicting sara composition of crude oil by means of nmr." fuel 110 (2013): 318-321. [5] s. a. mohammed and s. d. maan, “the effect of asphaltene on the stability of iraqi water in crude oil emulsions”, ijcpe, vol. 17, no. 2, pp. 37-45, jun. 2016. [6] leontaritis, k. j., j. o. amaefule, and r. e. charles. "a systematic approach for the prevention and treatment of formation damage caused by asphaltene deposition." spe production & facilities 9.03 (1994): 157-164. [7] ahmed, tarek. reservoir engineering handbook. gulf professional publishing, 2010. [8] b. craft, m. hawkins, r. terry, applied petroleum reservoir engineering, seconded., prentice hall,1990. [9] d. alobaidi, “permeability prediction in one of iraqi carbonate reservoir using hydraulic flow units and neural networks”, ijcpe, vol. 17, no. 1, pp. 1-11, mar. 2016. [10] schön, jürgen h. physical properties of rocks: fundamentals and principles of petrophysics. vol. 65.elsevier,2015. [11] tiab, djebbar, and erle c. donaldson. petrophysics: theory and practice of measuring reservoir rock and fluid transport properties. gulf professional publishing, 2015. [12] ezekwe, nnaemeka. petroleum reservoir engineering practice. pearson education, 2010. [13] f. h. m. al-mahdawi and k. saad, “enhancement of drilling fluid properties using nanoparticles”, ijcpe, vol. 19, no. 2, pp. 21-26, jun. 2018. http://www.editionstechnip.com/en/catalogue-detail/1159/essential-of-reservoir-engineering-vol-2.html http://www.editionstechnip.com/en/catalogue-detail/1159/essential-of-reservoir-engineering-vol-2.html https://books.google.iq/books?hl=en&lr=&id=lkn-ovihxduc&oi=fnd&pg=pp1&dq=%5b2%5d%09guo,+boyun.+petroleum+production+engineering,+a+computer-assisted+approach.+elsevier,+2011.&ots=43avq1re0b&sig=xxbaktg7ofb0labdfx_od8q1e3i&redir_esc=y#v=onepage&q=%5b2%5d%09guo%2c%20boyun.%20petroleum%20production%20engineering%2c%20a%20computer-assisted%20approach.%20elsevier%2c%202011.&f=false https://books.google.iq/books?hl=en&lr=&id=lkn-ovihxduc&oi=fnd&pg=pp1&dq=%5b2%5d%09guo,+boyun.+petroleum+production+engineering,+a+computer-assisted+approach.+elsevier,+2011.&ots=43avq1re0b&sig=xxbaktg7ofb0labdfx_od8q1e3i&redir_esc=y#v=onepage&q=%5b2%5d%09guo%2c%20boyun.%20petroleum%20production%20engineering%2c%20a%20computer-assisted%20approach.%20elsevier%2c%202011.&f=false https://books.google.iq/books?hl=en&lr=&id=pp_aagaaqbaj&oi=fnd&pg=pp1&dq=%5b3%5d%09speight,+james+g.+the+chemistry+and+technology+of+petroleum.+crc+press,+2014.&ots=sqyf4mg-bb&sig=gfn8lriod3jq8os1tfvgtc82ymu&redir_esc=y#v=onepage&q=%5b3%5d%09speight%2c%20james%20g.%20the%20chemistry%20and%20technology%20of%20petroleum.%20crc%20press%2c%202014.&f=false https://books.google.iq/books?hl=en&lr=&id=pp_aagaaqbaj&oi=fnd&pg=pp1&dq=%5b3%5d%09speight,+james+g.+the+chemistry+and+technology+of+petroleum.+crc+press,+2014.&ots=sqyf4mg-bb&sig=gfn8lriod3jq8os1tfvgtc82ymu&redir_esc=y#v=onepage&q=%5b3%5d%09speight%2c%20james%20g.%20the%20chemistry%20and%20technology%20of%20petroleum.%20crc%20press%2c%202014.&f=false https://www.sciencedirect.com/science/article/pii/s0016236112008241 https://www.sciencedirect.com/science/article/pii/s0016236112008241 https://www.sciencedirect.com/science/article/pii/s0016236112008241 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/80 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/80 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/80 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/80 https://www.onepetro.org/journal-paper/spe-23810-pa https://www.onepetro.org/journal-paper/spe-23810-pa https://www.onepetro.org/journal-paper/spe-23810-pa https://www.onepetro.org/journal-paper/spe-23810-pa https://www.onepetro.org/journal-paper/spe-23810-pa http://booksdl.org/get.php?md5=d3486fd74061537fbe643ecaf7edfe18&key=aa80d5f8vqxfjh71. http://booksdl.org/get.php?md5=d3486fd74061537fbe643ecaf7edfe18&key=aa80d5f8vqxfjh71. http://booksdl.org/get.php?md5=fad5293ff053f2f0f1cb2dd9fdffc2b8&key=zu2pk4b2uuo9ltg9. http://booksdl.org/get.php?md5=fad5293ff053f2f0f1cb2dd9fdffc2b8&key=zu2pk4b2uuo9ltg9. http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/85 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/85 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/85 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/85 https://books.google.iq/books?hl=en&lr=&id=uckhbgaaqbaj&oi=fnd&pg=pp1&dq=%5b10%5d%09sch%c3%b6n,+j%c3%bcrgen+h.+physical+properties+of+rocks:+fundamentals+and+principles+of+petrophysics.+vol.+65.elsevier,2015.&ots=ra0xsvsbak&sig=oofiqqjxg2k6fkwwdpewhe3krna&redir_esc=y#v=onepage&q=%5b10%5d%09sch%c3%b6n%2c%20j%c3%bcrgen%20h.%20physical%20properties%20of%20rocks%3a%20fundamentals%20and%20principles%20of%20petrophysics.%20vol.%2065.elsevier%2c2015.&f=false https://books.google.iq/books?hl=en&lr=&id=uckhbgaaqbaj&oi=fnd&pg=pp1&dq=%5b10%5d%09sch%c3%b6n,+j%c3%bcrgen+h.+physical+properties+of+rocks:+fundamentals+and+principles+of+petrophysics.+vol.+65.elsevier,2015.&ots=ra0xsvsbak&sig=oofiqqjxg2k6fkwwdpewhe3krna&redir_esc=y#v=onepage&q=%5b10%5d%09sch%c3%b6n%2c%20j%c3%bcrgen%20h.%20physical%20properties%20of%20rocks%3a%20fundamentals%20and%20principles%20of%20petrophysics.%20vol.%2065.elsevier%2c2015.&f=false https://books.google.iq/books?hl=en&lr=&id=uckhbgaaqbaj&oi=fnd&pg=pp1&dq=%5b10%5d%09sch%c3%b6n,+j%c3%bcrgen+h.+physical+properties+of+rocks:+fundamentals+and+principles+of+petrophysics.+vol.+65.elsevier,2015.&ots=ra0xsvsbak&sig=oofiqqjxg2k6fkwwdpewhe3krna&redir_esc=y#v=onepage&q=%5b10%5d%09sch%c3%b6n%2c%20j%c3%bcrgen%20h.%20physical%20properties%20of%20rocks%3a%20fundamentals%20and%20principles%20of%20petrophysics.%20vol.%2065.elsevier%2c2015.&f=false tiab,%20djebbar,%20and%20erle%20c.%20donaldson.%20petrophysics:%20theory%20and%20practice%20of%20measuring%20reservoir%20rock%20and%20fluid%20transport%20properties.%20gulf%20professional%20publishing,%202015. tiab,%20djebbar,%20and%20erle%20c.%20donaldson.%20petrophysics:%20theory%20and%20practice%20of%20measuring%20reservoir%20rock%20and%20fluid%20transport%20properties.%20gulf%20professional%20publishing,%202015. tiab,%20djebbar,%20and%20erle%20c.%20donaldson.%20petrophysics:%20theory%20and%20practice%20of%20measuring%20reservoir%20rock%20and%20fluid%20transport%20properties.%20gulf%20professional%20publishing,%202015. tiab,%20djebbar,%20and%20erle%20c.%20donaldson.%20petrophysics:%20theory%20and%20practice%20of%20measuring%20reservoir%20rock%20and%20fluid%20transport%20properties.%20gulf%20professional%20publishing,%202015. http://booksdl.org/get.php?md5=8f353d14d93fdbf72e5a14315f6f2f2e&key=vzyqjgagsz1rsx2l. http://booksdl.org/get.php?md5=8f353d14d93fdbf72e5a14315f6f2f2e&key=vzyqjgagsz1rsx2l. http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/162 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/162 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/162 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/162 l. w. farhan et. al. / iraqi journal of chemical and petroleum engineering 21,1 (2020) 45 52 05 أذابة االسفمت المترسب داخل المكامن النفطية بأستخدام مذيبات محمية 2و عادل شريف 1فالح المهداوي , 1ليث وارد 1 جامعة بغداد, كمية الهندسة, قسم هندسةالنفط1 الجامعة التكنولوجية, قسم تكنولوجيا النفط2 الخالصة هناك العديد من المكامن النفطية التي تعاني من فقدان تدريجي او مفاجئ لالنتاج بسبب ترسب االسفمت داخل تمك المكامن. ترسب االسفمت داخل المكامن النفطية يؤدي الى التضرر الطبقي وتغير التبممية المكمنية فقدان الضغط وكل هذا يؤدي الى انخفاض قيم االنتاج وبالتالي انخفاض القيمة االقتصادية لممشروع. وزيادة الهدف من هذه الدراسة هو استخدام مذيبات محمية ألذاية ترسبات االسفمت داخل المكامن النفطية. ثالث انواع حدد منهما. ثالث نماذج حضرت من من المذيبات المحمية اختيرت وهي النفثة الثقبمة والريفورميت ومزيج م الرمل بهيئة صخور وتم تمويثها مع وزن محدد من االسفمت. قيم النفاذية لهذه النماذج حسبت قبل وبعد المزج وبعد حقنها بالمذيبات المحضرة. كل قيم النفاذية تم تحويمها الى معدل التضرر الطبقي مقارنة مع النموذج غم من 22% عند مزج النموذج مع 22هرت حدوث تضرر طبقي بمعدل االصمي غير المموث. النتائج اض % بعد حقن الريفورميت والنفثة الثقيمة والخميط منهما , 12% , 11% , 12االسفمت. وهذا المعدل انخفض الى عمى التوالي. النفطية, الريفورمت, النفثة الثقيمة.: ترسب األسفمت, المذيبات المحمية العراقية, تضرر النفاذية, المكمامن الدالة الكممات available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.21 no.1 (march 2020) 53 – 59 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: sara s. zughar, email: sara1995105@gmail.com, name: ahmad a. ramadhan, email: 150073@uotechnology.edu.iq, name: ahmed k. jaber, email: ahmedkhalil1974@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. petrophysical properties of an iraqi carbonate reservoir using well log evaluation sara s. zughar a , ahmad a. ramadhan a , ahmed k. jaber b a petroleum technology dept./university of technology/iraq b directory of field development and reservoirs/ministry of oil/iraq abstract this research was aimed to determine the petrophysical properties (porosity, permeability and fluid saturation) of a reservoir. petrophysical properties of the shuiaba formation at y field are determined from the interpretation of open hole log data of six wells. depending on these properties, it is possible to divide the shuiaba formation which has thickness of a proximately 180-195m, into three lithological units: a is upper unit (thickness about 8 to 15 m) involving of moderately dolomitized limestones; b is a middle unit (thickness about 52 to 56 m) which is composed of dolomitic limestone, and c is lower unit ( >110 m thick) which consists of shale-rich and dolomitic limestones. the results showed that the average formation water resistivity for the formation (rw = 0.021), the average resistivity of the mud filtration (rmf = 0.57), and the archie parameters determined by the picket plot method, where m value equal to 1.94, n value equal to 2 and a value equal to 1. porosity values and water saturation sw were calculated along with the depth of the composition using ip v3.5 software. the interpretation of the computer process (cpi) showed that the better porous zone holds the highest amount of hydrocarbons in the second zone. from the flow zone indicator method, there are four rock types in the studied reservoir. keywords: petrophysical properties, porosity, permeability, shuiaba formation, well log. received on 31/08/2019, accepted on 01/11/2019, published on 30/03/0220 https://doi.org/10.31699/ijcpe.2020.1.8 1introduction interpretation of well log results is one of the important processes for engineers and geologists to identify the petrophysical properties. the log data is significant in reservoir engineering and used in the calculation, especially in the estimation of the reserve. the best interpretation for any structure of interest depends on the quality and quantity of log data available to analysts and the type of problem ‎[1]. the interpretation of the basic logs also includes the determination of; true total porosity, effective porosity, water saturation, salinity of the formation water, mud filtrate resistivity and true resistivity for the field. besides the porosity and the hydrocarbon saturation to calculate total reserves and predict the size of the formation containing hydrocarbon if the accumulation of hydrocarbon is commercial. for that, researchers can make interpretation for available logs that will help us to calculate the original oil in place ooip ‎[2]. the flow of fluid through a carbonate reservoir is a completely different process than the flows through sandstone layers. this difference is due in large part of carbonate rocks tend to have a more complex void system than sand rock. ‎[3]. much of the hydrocarbon reserves are found in carbonate rock. however, the characterization of the carbonate reservoir is quite complex compared to sand rock reservoirs error! reference source not found.. in the middle east, the giant fields containing hydrocarbon are in carbonate reservoirs, which cover about 50% of the world's hydrocarbon reserves ‎[5]. y field is located in northeastern iraq, and it has several pay zones, and they produce from the tertiary and cretaceous reservoirs which comprise the middle lower cretaceous qamchuqa group as the main reservoir system. the first well x-1 was founded in 1976 and the last well (x-33) was completed in 2008, depending on the seismic studies. ‎[6]. 2methodology six wells were selected in the y oilfield for achieving the main petrophysical parameters, table 1 and table 2 show the well log and core data that used in this study. the methods in this study can be summarized as follows: in the first step, environmental well log corrections were done, then, water formation resistivity and shale volume were calculated. lithology was then identified in which porosity estimation was required. the water saturation was determined by using the indonesian equation because it gives reasonable values. finally, water zones, movable and residual hydrocarbons were identified easily. https://doi.org/10.31699/ijcpe.2020.1.8 s. s. zughar et. al. / iraqi journal of chemical and petroleum engineering 21,1 (2020) 53 59 45 table 1. log and core data used in this study including a number of porosity and permeability measurements (data from iraqi oil ministry, unpublished) number of thin sections number if k and φ measurements number of plugs core sample intervals(m) log data depth intervals(m) well neutron density gr 27 284 260 3128-3226.9 3045-3229 3045-3229 3045-3229 x-1 75 102 102 3348-3379.9 3317-3510 3317-3510 3317-3510 x-2 14 3274-3350 3274-3350 3274-3350 x-4 3112-3200 3112-3200 3112-3200 x-5 41 3101-3165 3101-3165 3101-3165 x-13 18 3094-3154 3091-3296 3091-3296 3091-3288 x-14 table 2. depths and interval thicknesses of lithological units in the shuaiba formation at the studied wells in the y oil field unit thickness (m) unit intervals (m) units cored intervals (m) producing intervals (m) interval and thickness (m) wells 14 3045-3059 a 3128-3229 3045-3101 3045-3229 (184) x-1 56 3059-3115 b 114 3115-3229 c 12 3317-3329 a 3348-3380 3317-3510 (193) x-2 55 3329-3384 b 126 3384-3510 c 8 3274-3282 a 3274-3355 (81) penetrated x-4 52 3282-3334 b 16 3334-3350 penetrated part c 13 3112-3125 a 3120-3188 3112-3200 (88) x-5 55 3125-3180 b 20 3180-3200 penetrated part c 15 3101-3116 a 3101-3210 (109) penetrated x-13 49 3116-3165 logged part b 3150-3168 not penetrated c 11 3091-3102 a 3094-3154.3 3091-3275 (186) x-14 58 3102-3160 b 115 3160-3275 c 3results and discussions 3.1 environmental corrections of well logs appropriate corrections (such as shale impact, opening hole conditions, invasion depth, etc.) were applied to neutron, density and gamma-ray logs were applied before the well log analysis was done. current schlumberger charts were used for environmental corrections ‎[7]. many companies have correction models available in ip v3.5 software. the schlumberger corrections were used to the well records specified in the y field as shown in table 1 because most of the records are registered by schlumberger company. fig. 1 shows the environmental corrections for well x-4. the figure shows, there are no significant differences between the readings of the original records and the corresponding corrected records, except for small differences due to the washout envision effect (in some parts of the logs). corrections are made to check true values and to obtain them. fig. 1. environmental correction for well x-4 s. s. zughar et. al. / iraqi journal of chemical and petroleum engineering 21,1 (2020) 53 59 44 3.2 shale volume determination the calculation of shale volume is important parameters that must be identified during any explanation because it affects the values of water saturation and porosity. the shale also controls the presence of hydrocarbons [1]. the volume of shale is determined in the y field using gamma-ray, through the following formula [8]: (1) then convert the gamma-ray index into shale content by an empirical equation for old rocks ( ) ( ) (2) where, igr: gamma-ray index, gr log: gamma-ray log reading in the zone of interest, api units, gr min: minimum gamma-ray reading in a clean zone, api units, gr max: maximum gamma-ray reading in shale zone, api units. fig. 2 shows the result of shale volume determination in well x-4 contains shale volume greater than 50% but it represents a small part from the drilled interval. fig. 2. show shale volume determination in well x-4 3.3. porosity estimation the fluids stored in the pore spaces within the reservoir rocks could be gas, oil, and water. high porosity values indicate high capacities of the reservoir rocks to contain these fluids, while low porosity values indicate the opposite ‎[8]. total porosity describes the ratio of all pore volumes in a rock to the total volume containing voids, the following formula can be used to determine the density and neutron logs ‎[9] (3) where, d: porosity from density log. n: porosity from neutron log. while effective porosity can be estimated by subtracting the shale volume from the total porosity as shown below ‎[8] ( ) (4) the porosity can also be estimated depending on three types of logs that are affected by rock porosity which are neutron, sonic and density logs. in the porosity calculation process, the selection of well log type was based on the borehole conditions and the good match between the log and core porosities. fig. 3 shows the porosity calculated by a neutron, density and sonic logs, effective porosity and total porosity compression with core porosity in well x-2. in this paper, effective porosity (phe) was taken because it gives a good match with core porosity. fig. 3. comparisons porosity analysis for well x-2 s. s. zughar et. al. / iraqi journal of chemical and petroleum engineering 21,1 (2020) 53 59 45 3.4. fluid saturation determination the most important step in interpreting the log is the determination of water saturation. water saturation can be estimated from different equations by using ip software v3.5. there are many equations to estimate water saturation such as dual water, archie, simandoux, mod sinandoux, indonesian, mod indonesian, juhaz and waxman. archie equation can be used to calculate fluid saturation for clean formation depending on porosity (φ), the resistivity of formation water (rw), resistivity of formation (rt) as shown in equations below ‎[10]. archie’s equation [10] : (5) (6) indonesian and simindox equation depended on archie parameter (a, m, and n) in derivation to estimate water saturation for high percentage shale formations, where indonesian equation depended on estimate water saturation ‎[11]. simindox equation ‎[11]: √ ( ) ( ) (7) for indonesian [11] : [ [ ( ) ] ] (8) 3.5. bulk volume analyses and computer processed interpretation (cpi) the bulk volume of water is the unit volume of porous media occupied by water and the bulk volume of hydrocarbons is the amount of the pore volume of the hydrocarbon ‎[12]. (9) (10) cpi is a continuous result of log analyzes and interpretations in the attractive form containing porosity, fluid saturation, matrix analysis tracks. fluid saturation and matrix analysis tracks include bulk volume analysis of fluid and matrix. the fluids bulk volume represents a continuous distribution of the volume of fluids in the rock formation pore space ‎[13]. fig. 4 shows the cpi for well x-2. the cpi results show that the best porous zone with the highest percentage of movable hydrocarbon in the shuiaba reservoir was unit b. fig. 4. computer processed interpretation (cpi) for well x-2 3.6. cut off calculations cutoffs in petroleum engineering are limiting points at which the processing of flowing of fluid is stopped. a. porosity cut off elimination of the portion of the formation is low porosity and low permeability, therefore nonproductive. typically, the cutoff of porosity for sandstones is about 8 to 10% and for limestone about 3 to 5%. limestone’s lower porosity cutoff values reflect the propensity for limestone’s to be highly fractured ‎[14]. for shuaiba reservoir, porosity cut off estimated by using permeability porosity cross plot, by using common permeability cut off value (0.1 md) in the cross plot for petroleum reservoir porosity cutoff identified and its value about 0.05 as shown in the fig. 5. kz-2scale : 1 : 600 depth (3317.m 3510.05m) 12/10/2019 16:13db : final ip-work-2019 (2) 1 depth (m) 2 p o ro s ity / s w gammaray grc (gapi) 0. 150. cali (inch) 6. 16. porosity input nphic (decimal) 0.6 0. rhobc (g/cc) 1.7 2.7 dt (ms/f t) 500. 100. resistivity lldc (ohmm) 0.02 2000. msflc (ohmm) 0.02 2000. llsc (ohmm) 0.02 2000. saturation sw (dec) 1. 0. sxo (dec) 1. 0. porosity phit (dec) 0.3 0. phie (dec) 0.3 0. bvwsxo (dec) 0.3 0. bvw (dec) 0.3 0. phi-core (dec) 0.5 0. gas oil movable hyd water lithology vclav (dec) 0. 1. phie (dec) 1. 0. clay porosity dolomite limestone 3320 3340 3360 3380 3400 3420 3440 3460 3480 3500 1 2 3 s. s. zughar et. al. / iraqi journal of chemical and petroleum engineering 21,1 (2020) 53 59 46 fig. 5. core porosity cut off the cross plot of x-1 b. water saturation cut off remove part of the formation which contains a large amount of water in the pore space. water saturation cut off determine by using cumulative storage capacity, (phi*so), versus water saturation and curve plot was prepared by using log analysis results. as results, water saturation cut off was 0.6 as shown in fig. 6 fig. 6. water saturation cut off of x-1 fig. 7. clay volume cut off of x-1 c. clay volume cut off clay volume cut off mean elimination the portion of the formation which contains large quantities of shall. clay volume cut off determine by using, cumulative storage capacity, (phi*so), versus clay volume and curve plot were prepared by using log analysis results. as result, clay volume cut off was 0.24 as shown in fig. 7. 3.7. permeability prediction knowledge the permeability, which is the ability of rocks to transmission liquid, is important to understand the flow mechanisms in oil and gas reservoirs. permeability is better measured in the laboratory on corded rocks taken from the reservoir. coring is expensive and time-consuming compared to the electronic survey techniques most commonly used to obtain permeability information error! reference source not found. . several methods to predict permeability are the classical method, the prediction of the statistical curve and the flow zone indicator. in this study, the flow zone indicator (fzi) was used to predict permeability, because there is no core data for the shuiaba reservoir for that core data available for two wells are used to predict permeability in an uncored interval. the flow zone indicator (fzi) method used to classify core data into hydraulic units with specific fzi. this method provides accurate correlations between permeability and porosity if the fzi of reservoir rocks is known. the fzi is estimated from core data in the cored wells and is generally applied to un-cored wells by correlations with log attributes. the general approach is given inflowing equations ‎[14]: √ (11) (12) kozeny equation, by substitute rqi and φz with fzi, can be simplified as: (13) by taking the logarithm of both side of equation 4-6, the final approach can be written as follow, (14) where: k = permeability (md), øeff =effective porosity, (core porosity for nhr umr formation/halfaya field) fzi mean is the average flow zone indicator. øz is a normalized porosity (pore volume to grain volume ratio) (fraction), s. s. zughar et. al. / iraqi journal of chemical and petroleum engineering 21,1 (2020) 53 59 47 depending on the definitions of hu obtained from the cumulative probability plot, the log-log graphs for rqi versus øz were as shown in fig. 8. the graph of log permeability (k) vs. (ø) fig. 9 shows better using the fzi technique a comparison. the relationship between the porosity and permeability of each type of rock is illustrated using the power-law model; high correlation coefficients were obtained for all types of rock, so permeability can be estimated accurately from the curve equation for each type of rock. fig. 8. rqi versus phiz (øz) plot fig. 9. log permeability (k) versus phie plot 4conclusions this study allows the following conclusions: 1based on core data and log interpretation the shuiaba carbonates can be divided into three lithological intervals: an upper unit ( thickness about 8-15 m ) consist of dolomitic limestones; b a middle unit ( thickness about 52-56m ) consist of vuggy dolostones and dolomitic limestones, and c a lower unit ( thickness about 114-126 m) composed of shale-rich dolomitic limestones. 2the range of porosity in the shuaiba reservoir in y field about from 1 to 24% (average 9.5%). from the plot between k-core and phi-core, the value of cutoff porosity was determined to be 5% and this value was used to identify high-porosity zones in the reservoir. 3from the neutron density plot, m-n plot and the mid plot, it was concluded that the composition of shuiaba reservoir is mainly composed of dolomite and limestone. 4due to heterogeneous carbon rocks, the archie parameter must be correctly defined to evaluate it; incorrect values of the archie parameter will cause unacceptable errors in the volume of water saturation and in the calculation of the initial oil in place. 5the heterogeneity of carbonate reservoirs makes it somewhat difficult to apply the archie equation when its parameters depend highly on carbonate characteristics. so that we use indonesian method because it gives reasonable values of water saturation 6almost all wells in iraq interpreted by various cpi methods have used constant archie coefficients, while these parameters have different values, especially in carbonate formations that affect fluid saturation, and archie constant values give a low saturation of hydrocarbons 7from plot between rqi versus ( z) on log-log plot show there is four rock type in shuiaba reservoir (wackestone, packstone, mudstone and shale). nomenclature symbols description unit a, n, m archie’s parameters dimensionless φ porosity fraction sw water saturation fraction rw formation water resistivity ohm.m. rmf mud filtrate resistivity ohm.m. vsh shale volume fraction rt true formation resistivity, ohm.m. rxo flushed zone resistivity, ohm.m øn neutron derived porosity, fraction ød density derived porosity, fraction øe effective porosity, fraction øt total porosity fraction references [1] bassiouni, z., 1994,”theory measurement and interpretation of well logs”, society of petroleum engineers, pp: 385. [2] ahmed, t., 2009, “working guide to reservoir rock properties and fluid flow”, gulf professional publishing, usa, pp: 261 [3] s. j. mazzullo, 1986, ''stratigraphic approach of hydrocarbon exploration and exploitation''., vol.21, pp:265-281. https://store.spe.org/theory-measurement-and-interpretation-of-well-logs--p77.aspx https://store.spe.org/theory-measurement-and-interpretation-of-well-logs--p77.aspx https://store.spe.org/theory-measurement-and-interpretation-of-well-logs--p77.aspx https://books.google.iq/books?hl=en&lr=&id=xtfel9n_y5cc&oi=fnd&pg=pp1&dq=%5b2%5d%09ahmed,+t.,+2006,+%e2%80%9cworking+guide+to+reservoir+rock+properties+and+fluid+flow%e2%80%9d,+gulf+professional+publishing,+usa,+pp:+261&ots=ys90da4tle&sig=xqqcts06t4_cbqttxjwrfhkozns&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=xtfel9n_y5cc&oi=fnd&pg=pp1&dq=%5b2%5d%09ahmed,+t.,+2006,+%e2%80%9cworking+guide+to+reservoir+rock+properties+and+fluid+flow%e2%80%9d,+gulf+professional+publishing,+usa,+pp:+261&ots=ys90da4tle&sig=xqqcts06t4_cbqttxjwrfhkozns&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=xtfel9n_y5cc&oi=fnd&pg=pp1&dq=%5b2%5d%09ahmed,+t.,+2006,+%e2%80%9cworking+guide+to+reservoir+rock+properties+and+fluid+flow%e2%80%9d,+gulf+professional+publishing,+usa,+pp:+261&ots=ys90da4tle&sig=xqqcts06t4_cbqttxjwrfhkozns&redir_esc=y#v=onepage&q&f=false https://onlinelibrary.wiley.com/doi/abs/10.1002/gj.3350210305 https://onlinelibrary.wiley.com/doi/abs/10.1002/gj.3350210305 https://onlinelibrary.wiley.com/doi/abs/10.1002/gj.3350210305 s. s. zughar et. al. / iraqi journal of chemical and petroleum engineering 21,1 (2020) 53 59 48 [4] m. al-jawad and k. kareem, “geological model of khasib reservoircentral area/east baghdad field”, ijcpe, vol. 17, no. 3, pp. 1-10, sep. 2016. [5] f. s. kadhim, s. samsuri, a. idris. 2013, ''a review in correlation between cementation factor and carbonate rock properties'', life sci. j, 10(4), pp:2451-2458 [6] raheem, n.a.a., uleiwi, m., gilly,p., santos,a., gouellec,m., niang,m., darrieus,a., bonis,m., and scandiuzzi,s., 2008, “iraq y field joint study preliminary field development study”, exploration and production, total and ministry of oil, pp:135. [7] schlumberger log interpretation chart book, 2011, houston, pp: 310. [8] ezeke, n., 2010, “petroleum reservoir engineering practice”, prentice hall, pp:816. [9] schlumberger ―log interpretation manual/applications‖, houston, schlumberger well service, inc.v.2, 1 l6p, 1974. [10] hamada, g., m., 2011, "analysis of archie's parameters determination techniques in carbonate reservoirs", kacst, pp:1-10. [11] marsan, d., and pratma, r., n., 2015, '' well log interpretation and petrophysical analysis'', halliburton, pp:59. [12] bateman , r.m., 1985, ''open-hole log analysis and formation evaluation'' [13] sn tonietto, mz smoot, m pope, "ps pore type characterization and classification in carbonate reservoirs." (2014). [14] husham, g., 2013, '' enhanced oil recovery methods for extraction of crude oil in noor field'', master thesis. [15] h. ali baker, s. noori al-jawad, and z. imad murtadha, “permeability prediction in carbonate reservoir rock using fzi”, ijcpe, vol. 14, no. 3, pp. 49-54, sep. 2013. الخواص البتروفيزيائية لمكامن الكاربونيت العراقية باستخدام تقييم سجل اآلبار 2احمد خميل جبارو 1احمد عبد اهلل رمضان, 1ساره صالح زغير. الجامعة التكنولوجية /العراق /قسم تكنولوجبا النفط 1 دائرة تطوير الحقول والمكامن/ وزارة النفط /العراق 2 الخالصة يهدف البحث إلى تحديد الخواص البتروفيزيائية )المسامية والنفاذية وتشبع السوائل( لممكمن. يتم تحديد و x-2و x-1من تفسير بيانات السجل المفتوح ألبار ) yالخواص البتروفيزيائية لتكوين الشعيبة في حقل x-4 وx-5 وx-13 وx-14 اعتماًدا عمى الخواص البتروفيزيائية ، يمكن تقسيم تكوين الشعيبة الذي .) م( تتكون من 11-8متًرا تقريًبا ، إلى ثالث وحدات ليثولوجية: وحدة عميا )أ ، 191و 180يتراوح سمكه بين م( وهي مكونة من الحجر الجيري الدولوميتي ؛ 15-12ر جزئًيا ؛ وحدة متوسطة )ب ، حجر جيري مبمو متر سمًكا( التي تتكون من أحجار جيرية غنية بالصخر الزيتي والدولوميتية .. c ،> 110والوحدة السفمية ) = rmfالطين ) ( ، ومقاومة متوسط راشحrw = 0.021مقاومة الماء لمتكوين )تشير النتائج إلى أن متوسط (. بينما تم حساب 1، و = 2، ن = 1.91تحديد من طريقة بكت بموت )م = archie( ، ومعممات 0.57 (. يوضح تفسير ip v3.5قيم المسامية وتشبع الماء مع عمق التكوين باستخدام برنامج تفاعل البتروفيزياء ) مسامية تحصن أعمى نسبة مئوية من ( أن النتائج تشير إلى أن أفضل منطقة cpiعممية الكمبيوتر ) الهيدروكربون المتحرك في الشعيبة يركز الخزان في المنطقة الثانية. .مكمن الشعيبة ,النفاذية ,المسامية ,الكممات الدالة: الخواص البتروفيزيائية http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/209 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/209 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/209 http://www.lifesciencesite.com/lsj/life1004/328_20991life1004_2451_2458.pdf http://www.lifesciencesite.com/lsj/life1004/328_20991life1004_2451_2458.pdf http://www.lifesciencesite.com/lsj/life1004/328_20991life1004_2451_2458.pdf https://www.onepetro.org/conference-paper/omc-2011-130 https://www.onepetro.org/conference-paper/omc-2011-130 https://www.onepetro.org/conference-paper/omc-2011-130 https://www.semanticscholar.org/paper/ps-pore-type-characterization-and-classification-in-tonietto-smoot/d53a961483219bc7d66771d9ba0ad1a9ed5c9827 https://www.semanticscholar.org/paper/ps-pore-type-characterization-and-classification-in-tonietto-smoot/d53a961483219bc7d66771d9ba0ad1a9ed5c9827 https://www.semanticscholar.org/paper/ps-pore-type-characterization-and-classification-in-tonietto-smoot/d53a961483219bc7d66771d9ba0ad1a9ed5c9827 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/318 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/318 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/318 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/318 available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.21 no.1 (march 2020) 67 – 74 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: wallaa a. noori , email: 80020@uotechnology.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. simulation of two phase flow mixing co – current in t junction using comsol wallaa a. noori, dhiyaa a. hussein altimimi and bashar jawad kadhim university of technology abstract the analysis, behavior of two-phase flow incompressible fluid in t-juction is done by using "a computational fluid dynamic (cfd) model" that application division of different in industries. the level set method was based in “finite element method”. in our search the behavior of two phase flow (oil and water) was studed. the two-phase flow is taken to simulate by using comsol software 4.3. the multivariable was studying such as velocity distribution, share rate, pressure and the fraction of volume at various times. the velocity was employed at the inlet (0.2633, 0.1316, 0.0547 and 0.0283 m/s) for water and (0.1316 m/s) for oil, over and above the pressure set at outlet as a boundary condition. it was observed through the program that the shear rate increased in the mixing area and begins to decrease after the mixing area, for the pressure suddenly decreases in the mixing area and after this area begins to decrease linearly with the length of the tube. keywords: two-phase flow, comsol cfd, level method, simulation received on 31/05/2018, accepted on 23/03/2019, published on 30/03/0220 https://doi.org/10.31699/ijcpe.2020.1.10 1introduction in nature and industrial application, the two-phase flow appears broadly, the term mixture called on the two-phase flow ‎[1]. the parameter design can be simply modeled in a single-phase but the difficulty appears in two-phase of fluid flow, the complexity still exists to understand due to difficult behavior ‎[2]. advances in technology the mathematical models were interested to define the two-phase flow this attention becomes a challenge to the examiner ‎[3], ‎[4] , ‎[5]. usually, in various forms, two-phase can appear such as gas flow against the liquid flow, two liquids, liquid with existing solid. in petroleum manufacturing such as the production of crude oil and carrying one of the important phenomena in two-phase flow between oil and water. different phases influence every other hydrodynamically the combination for two-phase such as gas phase with liquid phase, liquidliquid phase with solid, and gas-phase with solid small certain kind of two-phase flow, frequently saw. in broad variety the two or multiphase occurrence in nature such as drops of rain in the air, volcanoes, sandstorms and snowstorm to additional practical uses in industries such as power manufacture, chemical processing, medicine and pharmaceuticals. in interior combustion engines, thinly atomized oil spray is injected into compressed air for efficient combustion and hence, fewer atmospheric contamination. the mixture that consists of oil and gas in the pipe in the system such as refrigeration, air-condition and wateroil mixture such as flow in the pipe, the transport of this system shows the two-phase flow. not needed to say, a well understanding of the physical phenomenon occurrence in multiphase flows will advantage to make present applications additional efficient and environmentally friendly‎[6]. several sorts of glide forms were expected by specific section speeds of the waft of binary immiscible liquids over the parallel pipelines by means of the volume of fluid approach. the projectile goes with the stream looked at small speeds, but the flow in the annular, the pressure behavior of mix inverse relationship with the oil velocity. also, it was observed that the quantity portion of oil is in two position center pipe and higher side of the pipe in the upper if the applied flow is maximum ‎[2]. the relationship between the pressure gradient and the velocity in case stratified for two-phase flow oil-water is positive ‎[7], ‎[8]. today, computational fluid dynamic (cfd) has progressed toward becoming a very important tool in simulation studies. several multidimensional statistical models were moving ahead to suggest stratified flows. these approaches for example lagrangian, the volume of fluid (vof), and level set. these approaches are in rule capable to minutely capture most of the physics of the applied flows. https://doi.org/10.31699/ijcpe.2020.1.10 w. a. noori et al. / iraqi journal of chemical and petroleum engineering 21,1 (2020) 67 74 86 bubbles and droplets are examples for small morphological formations these formations they cannot capture if the mesh is not sensible minor enough. one of the primaries tries to simulate mix inflows as joined the vof method with a two-fluid model in order to transfer simultaneously the advantages of both analytical formulations. another try a multifluid simulation of slugging phenomena in horizontal channels that existing a mechanistic move toward the guess of hydrodynamic slug beginning, growth and resulting improvement into nonstop slug stream in lines ‎[9]. in our work, the model of two-phase flow is worked out by means of the simulation program based on the level set approach. the numerical technique was used to find an approximation solution using the finite element method. it similarly offers a lot of roles that make the difference of differential equations between the node ‎[10]. the oilwater streams are exceptionally normal in the oil ventures. for the most part, the oil stage is moved in a multiphase stream state as water and oil are ordinarily delivered collectively. the closeness of water has a noteworthy impact amid the carriage of the oil ‎[11]error! reference source not found.. in our investigation, the two-phase flow of mix oilwater is assumed based on the finite element method (fem) wetted wall boundary condition. the investigation includes study behavior of velocity, pressure, a fraction of volume through a pipe with a certain condition. 2selection of the discretization technique the equations of the statistical approaches for multiphase flows are typically numerical method by means of the finite volume model (fvm) or fem method in an area over with limited finite-difference mode (fdm) for time discretization. an essential variance amidst these two approaches is that the fem could be simply enhanced in giving high request precision with additional computational monetary value, while it ends up mindboggling and hard to comprehend in high request exactness in alternate strategies error! reference source not found.. 2.1. the level set method the set technique is a statistical method that became added in osher & sethian’s paper ‎[16]. the set strategy has been one extremely advantageous structure from both hypothetical and numerical perspectives. it permits to define dramatic alteration in areas (as well as topological alteration) in a very strong way ‎[17]. particular data on the set approach could be determined by way of osher and fedkiw ‎[18]. the concept of the set technique is to describe the interface among the multi fluids with the aid of the usage of tacit function, the extent set feature (x), as shown in fig. 1. later decide on the kind of the tacit function, the area value that provide (x) = 0 create the interface among the multi incompressible liquids. another benefit of the set approach is that geometries that trade topology including division, and evolving holes, be able to be followed effortlessly and any other one is that the grid of the area does no longer want to be changed. the set method from its algebraic thought to its statistical calculations is obtainable within the next segments error! reference source not found.. 2.2. mathematical model formulation in this segment, an algebraic form could be advanced to talk about the two-phase flow. the fluid flow simulation can be built by the computational domain. an appropriate grid is taken into concern as the simulation. the condition situations are for the multi-phase (oil-water) in a level set. in this research, two-phase consist of two fluid incompressible and flow laminar, fig. 1. viewing the interface by an employ set function the governing equations of this situation become as follows at the initial condition (ic) and boundary condition (bc). in the computational area ω, where u present the mixture velocity, ρ present density, and µ present viscosity, g present the gravity and the surface tension force is present by fst. (1) ( ) ( ( )) (2) ( ( ) | | (3) where: ϕ is the phase arena dimensionless changeable, γ movement, ε is a regulatory interface factor, the mixture properties such as viscosity and density are the function of the water volume fraction vw . the water and oil volume fraction are vw =(1 + ϕ)/2 and v0 =(1ϕ)/2 respectively. over the interface viscosity and density are computed for the two-phase model according to: w. a. noori et al. / iraqi journal of chemical and petroleum engineering 21,1 (2020) 67 74 86 ( ) (4) ( ) (5) where: w and o that subscript to indicate the water and oil respectively error! reference source not found. the velocity of water (0.2633, 0.1316, 0.0547 and 0.0283 m/s) and oil (0.1316 m/s). the velocity u = u0, is the base at the inlet and the condition at the wall wetted fig. 2 present 2d domain for the circular tube with dimension (5 m width x 12.7[mm] height) and fig. 3 present mesh design. fig. 2. the field geometry fig. 3. the field meshes the physical properties of two fluid are given in table 1 and the parameter value is given in table 2. table 1. fluid phases of physical properties property sign phase of h2o phase of oil dynamic viscosity(pa∙s) µ 0.001003 pa∙s 0.0055 density (kg/m 3 ) ρ 998.2 kg/m3 828 oil-water interfacial tension([mn/m]) τ 39.6 table 2. parameters values used in simulation sign parameters values ε parameter controlling interface thickness tpf.hmax/2 m g gravity 9.8 m/s 2 ϒ reinitialization 0.9 m/s 3results and discussion in our research, the version of comsol that employed was 4.3 to simulate two-phase flow (oil-water). fig (4) present the velocity distribution for different positions (distance range from edge (0,1,5)). figs. show it shows the pressure suddenly drops at the mixing zone and after this zone its decreases linearly with pipe length, this means the velocity in pipe increase until reaching the end tube. the volume fraction of fluid one (water) and fluid two (oil) was studied at a different velocity, the fig. 7 & fig. 8 present volume fraction of water phase and oil phase line graph and two dimensions respectively, the figs. display the different behavior according to the velocity of the water middle pipe. fig. 5 clearly shows it shows the distribution of shear rate with increases in the mixed zone and after this zone it begins to decrease with length with some phases, but in general, the velocity is low at the boundary of pipe and then increases at the fluctuation difference between shapes because of different velocity and volume fraction. the pressure drop along the pipe at different velocity was studied and present in fig. 6. w. a. noori et al. / iraqi journal of chemical and petroleum engineering 21,1 (2020) 67 74 07 (a) (b) (c) (d) fig. 4. velocity dist. at diff. distance range (0, 1, 5) (a) v1 (b) v2 (c) v3 (d) v4 fig. 5. share rate against length domain fig. 6. pressure drop against length domain w. a. noori et al. / iraqi journal of chemical and petroleum engineering 21,1 (2020) 67 74 07 (a) (b) (c) (d) (e) (f) fig. 7. present volume fraction of water against pipe length at different velocity (a) line graph ,(b) 2d v1, (c)2d v2, (d)2d v3, (e) 2d v4, (f) 2d v5. w. a. noori et al. / iraqi journal of chemical and petroleum engineering 21,1 (2020) 67 74 07 (a) (b) (c) (d) (e) (f) fig. 8. present volume fraction of oil against the pipe length at different velocity (a) line graph ,(b)2d v1, (c)2d v2, (d)2d v3, (e) 2d v4, (f) 2d v5 w. a. noori et al. / iraqi journal of chemical and petroleum engineering 21,1 (2020) 67 74 07 4conclusion two-phase flow (water-oil) is simulated by comsol, the level set method was based on the cfd model. according to level set gained the difference report of the fluid flow observed the velocity magnitude is higher in pipe center and velocity at the boundary of the pipe is lowest. the shear rate increased in the mixed zone after this zone decreased with pipe length with small fluctuation. the volume fraction is variously with various velocities. the pressure drop observed in the pipe is a linear change expect mix zone. references [1] drew, d.a., (1983), "mathematical modeling of twophase flow". annual reviews on fluid mechanics, 15, 261-291. [2] desamala, a.b., dasamahapatra, a.k. and mandal, t.k., (2014), "oil-water two-phase flow characteristics in horizontal pipeline a comprehensive cfd study". international journal of chemical, molecular, nuclear, materials and metallurgical engineering, world academy of science, engineering and technology, 8, 360-364. [3] liao, q., liu, d., ye, d., zhu, x. and lee, d., (2011), "mathematical modelling of two-phase flow and transport in an immobilized-cell photo bioreactor". international journal of hydrogen energy, 36,1393913948. [4] morin, a., (2012), "mathematical modelling and numerical simulation of two-phase multi-component flows of co2 mixtures in pipes". phd thesis, norwegian university of science and technology, norway. [5] hudson, j. and harris, d., (2006), "numerical modeling of eulerian two-phase gas-solid flow". manchester institute of mathematical sciences, manchester, 1-41. [6] rahul garg (2009)."modeling and simulation of twophase flows” lib.dr.iastate.edu/etd/10657 [7] alias, a.z.m., koto, j. and ahmed, y.m., (2015), "cfd simulation for stratified oil-water two-phase flow in a horizontal pipe". international society of ocean, mechanical and aerospace scientists and engineers, 2, 1-6. [8] hu, h. and cheng, y.f., (2016), "modelling by computational fluid dynamics simulation of pipeline corrosion in co2-containing oil-water two-phase flow". journal of petroleum science and engineering, 146, 134-141. [9] thomas höhne, (2009), “experiments and numerical simulations of horizontal two phase flow regimes” seventh international conference on cfd in the minerals and process industries csiro, melbourne, australia. [10] yu, w.h. and wiwatanapattaphee, b., (2006), "finite element method and application". mistercopy publishing company,bangkok. [11] abed, e.m. and auda, z.a., (2014), "simulation and experiment of oil-water flow with effect of heat transfer in horizontal pipe". international journal of mechanical engineering and applications, 2,117-127. [12] h. neamah and a. a.alrazzaq, “torque and drag forces problems in highly deviated oil well”, ijcpe, vol. 19, no. 3, pp. 19-31, sep. 2018.. [13] s. a. lazim, s. m. hamd-allah, and a. jawad, “permeability estimation for carbonate reservoir (case study/ south iraqi field)”, ijcpe, vol. 19, no. 3, pp. 41-45, sep. 2018. [14] n. m. farhan, “effect of nanoparticles and surfactant on phase inversion of two phases”, ijcpe, vol. 18, no. 1, pp. 121-128, mar. 2017. [15] deniz kennedy, (2014), "level set methods for two-phase flows with fem" examensarbete 30 hp department of information technology uppsala university. [16] giordano, m., bonfiglioli, a. and magi, v., (2006), "a parallel finite element method for twophase flows". european conference on computational fluid dynamics, glasgow, 1-20. [17] m. sussman, p. smereka, and s. osher, (1994), "a level set method for computing solutions to incompressible two-phase flow", j. comput. phys., 114, 146-159. [18] s. osher and r. fedkiw, (2003), "level set methods and dynamics implicit surfaces", volume 153 of applied mathematical sciences, springer-verlag, new york. https://www.annualreviews.org/doi/pdf/10.1146/annurev.fl.15.010183.001401 https://www.annualreviews.org/doi/pdf/10.1146/annurev.fl.15.010183.001401 https://www.annualreviews.org/doi/pdf/10.1146/annurev.fl.15.010183.001401 https://pdfs.semanticscholar.org/722e/dff7138a9b33b2c2cf8c826400384a730603.pdf https://pdfs.semanticscholar.org/722e/dff7138a9b33b2c2cf8c826400384a730603.pdf https://pdfs.semanticscholar.org/722e/dff7138a9b33b2c2cf8c826400384a730603.pdf https://pdfs.semanticscholar.org/722e/dff7138a9b33b2c2cf8c826400384a730603.pdf https://pdfs.semanticscholar.org/722e/dff7138a9b33b2c2cf8c826400384a730603.pdf https://pdfs.semanticscholar.org/722e/dff7138a9b33b2c2cf8c826400384a730603.pdf https://pdfs.semanticscholar.org/722e/dff7138a9b33b2c2cf8c826400384a730603.pdf https://pdfs.semanticscholar.org/722e/dff7138a9b33b2c2cf8c826400384a730603.pdf https://pdfs.semanticscholar.org/722e/dff7138a9b33b2c2cf8c826400384a730603.pdf https://www.sciencedirect.com/science/article/abs/pii/s0360319911006781 https://www.sciencedirect.com/science/article/abs/pii/s0360319911006781 https://www.sciencedirect.com/science/article/abs/pii/s0360319911006781 https://www.sciencedirect.com/science/article/abs/pii/s0360319911006781 https://www.sciencedirect.com/science/article/abs/pii/s0360319911006781 https://ntnuopen.ntnu.no/ntnu-xmlui/handle/11250/234991 https://ntnuopen.ntnu.no/ntnu-xmlui/handle/11250/234991 https://ntnuopen.ntnu.no/ntnu-xmlui/handle/11250/234991 https://ntnuopen.ntnu.no/ntnu-xmlui/handle/11250/234991 https://ntnuopen.ntnu.no/ntnu-xmlui/handle/11250/234991 http://eprints.ma.man.ac.uk/151/ http://eprints.ma.man.ac.uk/151/ http://eprints.ma.man.ac.uk/151/ http://eprints.ma.man.ac.uk/151/ https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=1647&context=etd https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=1647&context=etd https://www.researchgate.net/profile/yasser_ahmed12/publication/289202374_cfd_simulation_for_stratified_oil-water_two-phase_flow_in_a_horizontal_pipe/links/568a3d3a08ae1975839d6d4a/cfd-simulation-for-stratified-oil-water-two-phase-flow-in-a-horizontal-pipe.pdf https://www.researchgate.net/profile/yasser_ahmed12/publication/289202374_cfd_simulation_for_stratified_oil-water_two-phase_flow_in_a_horizontal_pipe/links/568a3d3a08ae1975839d6d4a/cfd-simulation-for-stratified-oil-water-two-phase-flow-in-a-horizontal-pipe.pdf https://www.researchgate.net/profile/yasser_ahmed12/publication/289202374_cfd_simulation_for_stratified_oil-water_two-phase_flow_in_a_horizontal_pipe/links/568a3d3a08ae1975839d6d4a/cfd-simulation-for-stratified-oil-water-two-phase-flow-in-a-horizontal-pipe.pdf https://www.researchgate.net/profile/yasser_ahmed12/publication/289202374_cfd_simulation_for_stratified_oil-water_two-phase_flow_in_a_horizontal_pipe/links/568a3d3a08ae1975839d6d4a/cfd-simulation-for-stratified-oil-water-two-phase-flow-in-a-horizontal-pipe.pdf https://www.researchgate.net/profile/yasser_ahmed12/publication/289202374_cfd_simulation_for_stratified_oil-water_two-phase_flow_in_a_horizontal_pipe/links/568a3d3a08ae1975839d6d4a/cfd-simulation-for-stratified-oil-water-two-phase-flow-in-a-horizontal-pipe.pdf https://www.sciencedirect.com/science/article/abs/pii/s0920410516301449 https://www.sciencedirect.com/science/article/abs/pii/s0920410516301449 https://www.sciencedirect.com/science/article/abs/pii/s0920410516301449 https://www.sciencedirect.com/science/article/abs/pii/s0920410516301449 https://www.sciencedirect.com/science/article/abs/pii/s0920410516301449 https://journals.sagepub.com/doi/abs/10.1260/1757-482x.2.3.131 https://journals.sagepub.com/doi/abs/10.1260/1757-482x.2.3.131 https://journals.sagepub.com/doi/abs/10.1260/1757-482x.2.3.131 https://journals.sagepub.com/doi/abs/10.1260/1757-482x.2.3.131 https://journals.sagepub.com/doi/abs/10.1260/1757-482x.2.3.131 http://www.mecheng.org/article/220/10.11648.j.ijmea.20140206.16 http://www.mecheng.org/article/220/10.11648.j.ijmea.20140206.16 http://www.mecheng.org/article/220/10.11648.j.ijmea.20140206.16 http://www.mecheng.org/article/220/10.11648.j.ijmea.20140206.16 http://www.mecheng.org/article/220/10.11648.j.ijmea.20140206.16 https://journals.sagepub.com/doi/abs/10.1260/1757-482x.2.3.131 https://journals.sagepub.com/doi/abs/10.1260/1757-482x.2.3.131 https://journals.sagepub.com/doi/abs/10.1260/1757-482x.2.3.131 https://doi.org/10.31699/ijcpe.2018.3.3 https://doi.org/10.31699/ijcpe.2018.3.5 https://doi.org/10.31699/ijcpe.2018.3.5 https://doi.org/10.31699/ijcpe.2018.3.5 https://doi.org/10.31699/ijcpe.2018.3.5 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/198 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/198 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/198 http://www.diva-portal.org/smash/record.jsf?pid=diva2%3a770199&dswid=-2005 http://www.diva-portal.org/smash/record.jsf?pid=diva2%3a770199&dswid=-2005 http://www.diva-portal.org/smash/record.jsf?pid=diva2%3a770199&dswid=-2005 http://www.diva-portal.org/smash/record.jsf?pid=diva2%3a770199&dswid=-2005 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https://dl.acm.org/doi/book/10.5555/920907 https://dl.acm.org/doi/book/10.5555/920907 https://dl.acm.org/doi/book/10.5555/920907 https://dl.acm.org/doi/book/10.5555/920907 https://asmedigitalcollection.asme.org/appliedmechanicsreviews/article/57/3/b15/463820/theory-and-applications-of-viscous-fluid-flows https://asmedigitalcollection.asme.org/appliedmechanicsreviews/article/57/3/b15/463820/theory-and-applications-of-viscous-fluid-flows https://asmedigitalcollection.asme.org/appliedmechanicsreviews/article/57/3/b15/463820/theory-and-applications-of-viscous-fluid-flows https://asmedigitalcollection.asme.org/appliedmechanicsreviews/article/57/3/b15/463820/theory-and-applications-of-viscous-fluid-flows w. a. noori et al. / iraqi journal of chemical and petroleum engineering 21,1 (2020) 67 74 07 محاكاة عممية خمط نظام متعدد االطوار في انبوب متعامد باستخدام برنامج الكومسل بشار جواد كاظم و ضياء عبد الرسول حسين ,والء عبد الهادي نوري الجامعة التكنولوجية الخالصة تحميل سموكية الجريان المتعدد االطوار لمموائع الغير انضغاطية في في االنبوب المتعامد ينجز بواسطة في بحثنا تم دراسة سموك المحاكاة باستخدام البرامج الحاسوبية والتي تستخدم لمختمف التطبيقات الصناعية. . تم دراسة 4.3برنامج الكومسل اصدار تدفق نظام متعدد )ماء مع نفط( باستخدام موديل المستويات باستخدام العديد من المتغيراة مثل توزيع السرعة و ومعدل القص والضغط و النسبة الحجمية لمموائع. تم استخدام سرع متر/ثانية(. لوحظ 0.1316متر / ثانية( و ) 0.0283و 0.0547، 0.1316، 0.2633) مختمفة لمماء في منطقة الخمط ويبدأ بالتناقص بعد منطقة الخمط, بالنسبة لمضغط من خالل البرنامج تزايد معدل القص ينخفض فجأة في منطقة الخمط وبعد هذه المنطقة يبدا باالنخفاض بصورة خطية مع طول االنبوب. الموائع يةنظام متعدد االطوار , كومسل , محاكاة, ديناميك الدالة: الكممات available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.21 no.3 (september 2020) 29 – 37 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name sabreen lateef kareem, email: sabreenl.kareem@uokufa.edu.iq, name: ahmed a mohammed, email: ahmed.abedm@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. removal of tetracycline from wastewater using circulating fluidized bed sabreen lateef kareem a and ahmed a mohammed b a environmental planning department, college of physical planning, university of kufa, iraq b environmental engineering department, college of engineering, university of baghdad, baghdad, iraq abstract in this study, the circulating fluidized bed was used to remove the tetracycline from wastewater utilizing a pistachio shell coated with zno nanoparticles. several parameters including, tetracycline solution flowrate, initial static bed height, tetracycline initial concentration and airflow rate were systematically examined to show their effect on the breakthrough curve and the required time to reach the adsorption capacity and thus draw the fully saturated curve of the adsorbent. results showed that using zno nanoparticles will increase the adsorbent surface area and pores and as a result the adsorption increased, also the required time for adsorbent saturation increased and thus the removal efficiency may be achieved at minimum antibiotic flowrate, maximum bed height, higher antibiotic concentration, and higher airflow rate. also, a minimum fluidization velocity correlation was developed in this study. this correlation was found to be a function of liquid velocity, bed height, particle size, and particle density. the results showed that circulating fluidized bed has a better performance and last more than two hours before the bed biomass exhausted in comparison with traditional fluidized bed. keywords: tetracycline, circulating fluidized bed, minimum fluidization velocity, bed height, breakthrough curve received on 13/12/2019, accepted on 23/01/2020, published on 30/09/2020 https://doi.org/10.31699/ijcpe.2020.3.4 1introduction contamination of water resources by toxic chemicals is one of the community's greatest environmental challenges, especially when these resources were the only viable drinking water source [1], [2]. antibiotics are highly consumed compounds among pharmaceutical drugs due to their efficacy in the treatment of a wide range of bacterial infections in human, livestock, poultry and fish [3].antibiotics considers as a special medicines because it can affect pathogenic bacteria when leaving human tissues and cells unused [4], [5]. it is very important to remove antibiotic residues before discharging sewage into the atmosphere because some types of them are persist and can be toxic for aquaculture , but it usually involves high costs [6]. advance oxidation process (aop) can transform or even fully mineralize antibiotic molecules into simple compounds, but the some disadvantage of these process were high cost and difficult to remove completely on an industrial scale [7]. as a result, physicochemical technologies prove to be a highly appropriate treatment choice for organic waste product [8]. adsorption process is very effective, operates simply and is relatively inexpensive [9]. adsorption method is commonly used to eliminate organic chemicals in polluted sites using suitable adsorbents [8]. recently, agricultural wastes have attracted great attention from researchers in their initial or modified forms to be used as adsorbents in treatment systems’.. because of their minimal cost and widespread existence in nature, such pistachio shells, banana peels, hazelnut straws, walnut shells orange peels, rice husks, oat hulls and ground nut shells [10]. the removal of contaminants using nanoparticles has emerged as an interesting area of research due to their unique properties. also, they offer opportunities for higher efficiency and cost-effectiveness due to the higher surface area and higher active sites that modify any material during nanocomposite preparation [11]. the most effective method is maximizing the adsorbent mechanical strength by coating the surface with nanoparticles which also increasing the adsorbent surface area and adsorption ability [12]. the nanoparticles adsorbents used primarily for treating wastewater are synthesized from silver, alumina, zinc oxide, copper oxide iron oxide, , titanium oxide, stannous oxide and some alloys [13]. some undesirable problems of pure nanoparticles as adsorbents are expensive needs advance filtration procedure for separation from aqueous liquids and large agglomeration tendency which reduce the reactivity in traditional treatment methods [14]. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:sabreenl.kareem@uokufa.edu.iq mailto:ahmed.abedm@yahoo.com http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2020.3.4 s. l. kareem and a. a. mohammed / iraqi journal of chemical and petroleum engineering 21,3 (2020) 29 37 30 so, traditional adsorbents coated with nanoparticles are an effective alternate in avoiding the difficulties of using pure nanomaterial and increasing the main adsorbents efficiency to remove pollutants from different origins [15]. zinc oxide (zno) nanoparticles can be used as essential adsorbent for the removing of antibiotics due to the low production costs and the opportunity for using in diverse fields [16]. a new form of reactor known as gas, liquid and solid circulating fluidized beds (glscfbs) has been used, in which the adsorbent is circulated between the downer and the riser [17]. glscfbs providing extra advantages to the old-style fluidized bed which include, high contact efficiency between liquid–solid, operated continuously because adsorption and desorption work simultaneously that the particles circulated between two separate columns [18] reduced back mixing of phases, greater throughput and improved mass transfer owing to the higher velocity and uniform flow pattern [19]. to the best of our knowledge ,no research investigated the efficiency of pistachio shell (pis) coated with zno nanoparticles (cps) for the elimination of antibiotic from wastewater .so that this work aims to examine the capability of cps for treatment of wastewater contaminated with tec by circulated fluidized bed. 2materials preparation 2.1. chemicals powdered tec, purity: 98%, were taken from general company for drugs industry (samarra, iraq) without more purification. stock solution of tec, was prepared by dissolving a suitable amount (according to concentration required) of powdered tec in 1 l of distilled water. due to the laboratory instability conditions, solution should be prepared daily at the experiments time. znonp was solid, white odorless powder with density equal to5600 kg/m 3 and mw=81.4 g/mol. table 1 displays the properties of tec and zno nanoparticles. 2.2. adsorbent preparation cps was prepared as follow. 1pis shells were locally collected, cleaned, washed with distilled water for 2–3 hours, and then dried at 105 °c using suitable oven for 24 hrs. 2the dried pis shell prepared were grinding and sieved. some pis prepared amounts were characterized, and the residual was stored for the zno nanoparticles znonp surface coating. 3.znonp obtained from xi’an lyphar biotec co., ltd, china. pis coating with the znonp was done using an ultrasonic device. 4 the znonp were mixed with acetone as a suitable dispersant in an ultrasonic for 30 min. and then the prepared pis were added in different mass and shaken for 2 hrs to obtain cps 5finally, the dried cps was kept in stoppered containers to be used in the necessary experiments. fig. 1 shows the cps preparation. . table 1. main characteristics of antibiotics studied compound abbr. formula mw (g/mol) pka chemical structure tetracycline tec c22h24n2o8 480.9 pka1 =3.3 pka2 = 7.7 pka3 = 9.27 2.3. adsorbent characterization techniques an x-ray diffractometer (xrd) was used to obtain xrd patterns of the pis, zno and cps crystalline structure in range of 2θ from 20° to 80°, with a step width of 0.02° and scan rate of 1° / second. in another hand, scanning electron microscopy (sem) images were conducted to detect the changes in the surface morphology that occur due to the adsorption process. the specific surface area sbet of the samples were carried out by a micrometrics instrument company, usa, asap2020 giving to the bet (brunauer, emmet and teller) model fig. 1. preparation of cps table 2. parameters range tested in cfb c o n ti n u o u s parameters range purpose liquid flow rate (l/hr) 18, 21 and 24 to find optimum flow rate and to find the effect of flow rate on breakthrough curves. bed height, cm 2, 4 and 6 to study the effect of cps bed height on breakthrough curves. initial concentration, mg/l 10,30 and 50 to study the effect of tec initial concentration on breakthrough curves air flow rate (cc/min) 400, 600 and 800 to find the optimum air flow rate for fluidization. pis pis powder zno cps s. l. kareem and a. a. mohammed / iraqi journal of chemical and petroleum engineering 21,3 (2020) 29 37 31 2.4. circulating fluidized bed fig. 2 show the schematic diagram for cfb column used in removal of tec from wastewater and table 2 represents the major parameters examined. fig. 2. glscfb schematic diagram 1: feeding tank, 2: valve, 3: pump, 4: air compressor, 5: flow meter of liquid, 6: gas flow meter, 7: distributer, 8: distilled water for the downer 9: treated wastewater, 10: downer column, 11: solid-liquid separator, 12: riser column. 3results and discussion 3.1. x-ray diffraction characterization xrd analysis results of cps, zno, and pis and in the range of 5-60° are depicted in fig.3. xrd of zno in fig.3a which show that 100% percent of material was zno and hexagonal structure also this result was proved by comparing given material xrd peaks with standard zno xrd card, average diameter size of znonp calculated using (debye-scherrer formula) eq.1 [14]. bcosθ 0.89λ d  (1) where: d, represents the crystallite size, b, refers to the full-width at half maximum (fwhm) in radians, λ=0.15406 nm is the wavelength and θ is the half differection angle of 2θ. by applying eq.1 znonp diameter were found to be 20.9 nm. fig. 3 b and c depicts xrd forms of pis and cps, respectively. the pis xrd analysis fig. 3 b displays that the pis main ingredients were cristobalite (97.4%), and periclase (2.6%). xrd analysis of cps displays the forming of new peaks as seen in fig. 3 c owing to the newly resulted znonp layers. however, peak diffraction is observed at “((2θ)) = 31.7288, 34.3877, 36.2432, 47.5063, 56.5137 and 62.8756, which related to the reflection from (100), (002), (101), (102), (110) and (103) planes, respectively”. these were owing to the zno layer (84.3%) and similarly showed that the shells of the pis were shielded with pure znonp [5]-[20], standard xrd card of zno shown in fig. 4. 3.2. scanning electron microscopy (sem) the sem analysis was conducted to investigate the shape and surface morphology of the natural pis, cps and cps loaded with antibiotics. the representative images are shown in fig. 5 (a-c) .the surface morphology of natural pistachio shell before preparation of the composite was shown in fig. 5 a, this figure shows that the pis surface was coarse, regular with spherical irregular aggregates. numerous small pores and cavities were detected making pis a good supportive surface for znonp. the sem of the cps fig. 5 b indicated that the cps surface is coarse; as well as it contains several nonuniformly and separated aggregates. so, there are many great ravines and extended grooves in the cps outer wall. these cps surface morphological characteristics, represents as a positive instant provide surface area for tec molecules sorbing. in this direction, the specific surface area of pis was determined to be equal to 0.972 m 2 /g, which was significantly increased after coating with zno nanoparticles to be equal to 4.234 m 2 /g these allowing tec molecules to enter and interact with surface functional groups. comparing fig. 5 b and cps sem image after tec adsorption fig. 5 c, the morphological properties of cps was significantly altered during the tec adsorption. the cps surface become bright and smoother, and several pre-separated aggregates are coalesced as pore surfaces were entirely filled with tec molecules, this remark states that tec were adsorbed onto the active surface groups exist inside the pores and the well-formed pores on the cps may be the main reason behind the high antibiotics uptake [21], [22]. fig. 3. xrd forms of the (a) zno (b) pis and (c) cps s. l. kareem and a. a. mohammed / iraqi journal of chemical and petroleum engineering 21,3 (2020) 29 37 32 fig. 4. xrd standard card of zno nanoparticles fig. 5. sem pictures of (a) pis (b) cps and (c) cps after tec adsorption 3.3. continuous mode experiments a. minimum fluidization velocity (ulmf) the minimum fluidization velocity (ulmf) in the instance of gas-liquid-solid fluidization (glsf) and liquid represents a continuous phase usually defined as the superficial velocity of liquid (ul) at which the bed looks fluidized for a known superficial velocity of gas (ug) [23] ulmf required to attain fluidization obtained from the bed pressure drop (pd) against ul scheme at a constant ug. ulmf in this study has been obtained as displayed in fig. 6 a-c. from fig. 6 a, it is noticed that initial static bed height hs affect ulmf, when hs increase, pressure drop increase then ulmf increase [24]. this is due to that fluidization bed is achieved when the upward drag and inertial forces applied by the fluids on the particles equals to the bed buoyant weight, the effect of initial static bed height hs on the ulmf only be expected [25]. from fig. 6 b, it is noticed that ulmf rises with increasing particle size(dp) increase. ug also affect ulmf, ulmf reduces as ug increased which confirming that bubbles support fluidization. the rate of ulmf is decreasing usually high at lower ug values and low as gas velocity increasing. also at higher ug, the ulmf becomes nearly constant fig. 6 c [23]. (a) (b) (c) fig. 6. pressure drop variant with ul for a) different hs value at dp = 0.54mm and ug = 0.0024 m/s, b) for different dp at hs = 0.06m and ug = 0.0024 m/s, and c) for different ug value at dp = 0.65 mm and hs = 0.06 m the experimental data for minimum liquid fluidization velocity are presented in table 3 , and can be correlated by non-linear regression analysis as illustrated in eq.2 which can be used in similar systems for the prediction of ulmf with coefficient of determination (r 2 ) = 0.9789 fig. 7. eq. 2 can applied in reynolds number (re) range (0.453.25) which is calculated by eq.3.from eq.2, it can be concluded that the particle size has a larger effect than other parameters on minimum fluidization velocity and as the ug increased, ulmf decreased due to the effect of ug of particle on fluidization ulmf=0.00184 ug -0.343 dp 1.198 hs 0.484 ρs -0.351 (2) 𝑅𝑒 = 𝜌 𝑉𝑑 µ (3) s. l. kareem and a. a. mohammed / iraqi journal of chemical and petroleum engineering 21,3 (2020) 29 37 33 table 3. experimental data obtained and correlated for ulmf correlation ulmf exp (m/s) dp(mm) ug(m/s) hs(m) density(kg/m 3 ) sse 0.0012 0.54 0.0024 0.02 0.715 5.6178e-10 0.0016 0.54 0.0024 0.04 0.715 2.0222e-09 0.002 0.54 0.0024 0.06 0.715 2.1992e-12 0.0016 0.45 0.0024 0.06 0.7482 2.7828e-10 0.0024 0.65 0.0024 0.06 0.6824 1.9765e-08 0.0036 0.65 0.0008 0.06 0.6824 1.0273e-08 0.0032 0.65 0.0016 0.06 0.6824 7.8901e-08 0.0024 0.65 0.0032 0.06 0.6824 9.5688e-09 0.002 0.65 0.004 0.06 0.6824 1.7629e-08 fig. 7. comparison between experimental and predicted ulmf since 0.54 mm cps particle size was used in continuous system and as shown in table 3, the minimum bed required to fluidized this size was 0.002m/s (250 cc/min) (15 l/hr)at air velocity 0.0024 m/s (300cc/min). therefor 18 l /hr was the minimum water flow rate tested in continuous experiments, flow rates upper than the minimum examined to rise the mixing and studying its influence on the antibiotics removal efficiency. b. breakthrough curves by plotting c/co versus time for tec, the breakthrough curves for each antibiotic were obtained. b1. effect of liquid flow rate steeper breakthrough curves resulted with increasing flow rate because as the flow rate become high, the residence time for tec in column become shorter. also, there is a possibility for tec to remain in the outlet stream from the column before equilibrium achieved because of contact time reduction. the results showing the effect of liquid flow rate on the removal efficiency of tec are plotted in fig.8. the liquid phase residence time decreases with a ul increase, (breakthrough time for 18, 21, and 24 l/hr flowrate was 380, 340, and 300 min respectively) thus adsorption time reduced and higher pollutant concentration noticed in raffinate stream. these results agree with that obtained by [26]. 18 l/hr. was chosen as the best solution flow rate for the next experiments. fig. 8. effect of flow rate on removal of tec at initial conditions 6 cm, 10 ppm, and 600cc/min b2. effect of cps bed height (hs) the bed height is considered as a major adsorption process design factor and its effect was studied. the experimental breakthrough curves are present in fig.9. these figures show that by increasing bed height, the time needed to reach equilibrium increased because long contact time occurred between contaminants solution and particles (breakthrough time for 6, 4 and 2 cm was 380,340 and 320 min, respectively). small bed heights will be saturated in shorter time; this displays that at small bed height the concentration ratio of adsorbate waste rises faster than that for a longer bed height. besides, as bed height increased, the surface area or sorption sites increase improving the sorption process. in the case of constant flow rate, increasing hs will increase the tec solution contact time, and improve the tec removal efficiency [27].so, 6 cm bed height was chosen as the optimum value for the next experiments. fig. 9. bed height effect on removal efficiency of tec at initial conditions 18 l/hr, 10 ppm, and 600cc/min b3. influence of initial concentration the effect of different initial antibiotic concentrations (10, 30 and 50 ppm) was examined at constant water and air flow rate and bed height. the experimental breakthrough curves resulted are illustrated in fig. 10 for antibiotics adsorption in terms of c/co versus time. in this figure, it is obvious that saturation time decreases with increasing an initial concentration and inverse relation between the breakpoint and initial concentration (breakthrough time for 10, 30 and 50 ppm was 380,280 and 220min). low initial solute concentration make the saturation time of diffusion rate longer. s. l. kareem and a. a. mohammed / iraqi journal of chemical and petroleum engineering 21,3 (2020) 29 37 34 as the tec influent concentration increases, the adsorption capacity also increases. this is attributed to a high concentration difference (driving force for adsorption) between in liquid and solid phase also, may increase solute mass transfer rate to contact adsorbent active free sites. if the initial antibiotic concentration is high, faster bed saturation occurring and the slope of the breakthrough curve is higher, so 10 ppm initial antibiotic solution concentration was chosen as the best value for the next experiments [26], [27]. fig. 10. effect of initial concentration on removal efficiency of (a) tec, (b) cip and (c) amo at initial conditions 18 l/hr, 6 cm , and 600cc/min b4. air flow rate effect fig. 11 shows the effect of air flow rate variation (400cc/min, 600cc/min and 800cc/min) on breakthrough curve. the breakthrough curve plot obtained at 800cc/min displays a sharper shape compared with lower air flow rate curve. this is due to that long time is required to reach saturation in the case of high air flow rate which is because of more turbulent flow that reduces the resistance of mass transfer. breakthrough time for 400,600 and 800 cc/min was 360,340 and 280 min, respectively [28]. fig. 11. effect of air flow rate on breakthrough curve of tec, at initial conditions 18 l/hr, 6 cm, and 10 ppm c. comparison between traditional fluidized bed and circulated fluidized bed the difference between traditional fluidized beds (conventional) vs. the circulated fluidized bed (cfb) is shown in fig. 12. the same conditions were used for each system, 10 mg/l as tec concentration, (6 cm) for bed height, 18 l/hr. as liquid flow rate, and 400cc/min as gas flow rate. the results obtained show the efficiency of cfb on the removal of tec. so the cfb has better result and last for more than 2 hours before the cps exhausted. in a cfb, solid particles are circulated between the riser and the downer at higher velocities compared to conventional fluidized beds, which leads to better contacting efficiency between phases, and higher mass transfer can be achieved with cfbs, which makes this type of reactor more preferable over the conventional fluidized beds. it has also been reported that the glscfb provides higher gas holdup, more uniform bubble sizes, better interphase contact, and more efficient heat transfer into or out of the bed. for some gas-liquid-solid reaction systems, solid adsorbent lose their activity due to deposition of antibiotic. on their surfaces, and need regeneration outside the bed. by using an accompanying down comer as a regenerator, both reaction and regeneration of the catalysts can be coupled by a continuous circulating operation. the liquid velocity is not enough to entrain the particles and wash them out of the column in conventional fluidization, while in circulated fluidized bed, the particles were carried to the top of the column by using high liquid velocity and then return them to the bottom by a recycle line or column [9]. fig. 12. traditional fluidized bed (tfb) vs. cfb for the removal of tec at initial conditions 18 l/hr as flow rate, 6 cm as bed height, 10 mg/l as initial concentration, and 800 cc/min as gas flow rate 4conclusion cps was found to be feasible media for use as a bed column for the removal of tec from contaminated water. a fluidized -bed column was used to investigate the sorption of all antibiotics studied and it was depended on feed flow rate, initial antibiotics concentration and bed height of adsorbent. the minimum fluidization velocity of bed was affected by ug, dp, hs and particle density. s. l. kareem and a. a. mohammed / iraqi journal of chemical and petroleum engineering 21,3 (2020) 29 37 35 the variation of liquid superficial velocity from 0.0024 to 0.0032 result an obvious depletion in sorption removal efficiency. the variation of bed height from 0.02 to 0.06 m for each antibiotics resulted in an obvious increase in time to reach c/co equal to 1. increasing initial contaminant concentration causes a decrease in biosorption capacity and increasing the time required for cps to be fully saturated. finally, increasing air flow rate increase the time required for cps to reach saturated. nomenclature abbreviation description cps pistachio shell coated with zinc oxide dp particle diameter glsfb gas-liquis-solid fluidized bed hs bed height pd pressure drop pis pistachio shell tec tetracycline ug gas velocity ul liquid velocity ulmf minimum fluidization velocity references [1] h.m.selman,a.a.mohammed,removal of-copper ions-from aqueous solution using liquid-surfactantmembrane technique, iraqi journal of chemical and petroleum engineering 20 ( 2019) 31 – 37. [2] a.a. al-haleem, k. m abed, treating of oil-based drill cuttings by earthworms, research journal of pharmaceutical, biological and chemical sciences 7(2014) 2088-2094. [3] m.s. legnoverde, s. simonetti, e.i. basaldella, influence of ph on cephalexin adsorption onto sba15 mesoporous silica: theoretical and experimental study. applied surface science, 300(2014) 37-42. [4] a.w. al-shahwany, a. a. al-hemiri, k.m. abed, comparative evaluation of alkaloids extraction methods from the root bark of punica granatum linn, advances in bioresearch 4(2013) [5] a.a. mohammed, s.l kareem, adsorption of tetracycline fom wastewater by using pistachio shell coated with zno nanoparticles: equilibrium, kinetic and isotherm studies. alexandria engineering journal,58(2019)917-928. [6] a. watkinson, e.murby, s. costanzo, removal of antibiotics in conventional and advanced wastewater treatment: implications for environmental discharge and wastewater recycling. water resources, 41 (2007) 4164–4176. [7] m. mehrjouei, s. müller, d.möller, energy consumption of three different advanced oxidation methods for water treatment: a cost-effectiveness study. journal of cleaner production, 65( 2014) 178– 183. [8] v. homem, l. santos, degradation and removal methods of antibiotics from aqueous matrices—a review. journal of environmental management, 92(2011) 2304–2347. [9] a.a.najim ,a.a. mohammed, biosorption of methylene blue from aqueous solution using mixed algae,19(2018)1-11. [10] a.a. mohammed, biosorption of lead, cadmium, and zinc onto sunflower shell: equilibrium, kinetic, and thermodynamic studies,16(2015)91-105. [11] m. yang, j. he, x. hu, c. yan, z. cheng, cuo nanostructures as quartz crystal microbalance sensing layers for detection of trace hydrogen cyanide gas. environmental science and technology, 45(2011) 6088-94. [12] z.chen, x. jin, z. chen, m. mallavarapu, r. naidu, removal of methyl orange from aqueous solution using bentonite-supported nanoscale zerovalent iron. journal of colloid and interface science, 363(2011) 601–607. [13] j. chen, w.chen, d.zhu, adsorption of nonionic aromatic compounds to single walled carbon nanotubes: effects of aqueous solution chemistry. environmental science and technology, 42(2008) 6862-6868. [14] a.a. mohammed, t.j. al-musawi, s.l. kareem, m. zarrabi, a.m. al-ma'abreh, simultaneous adsorption of tetracycline, amoxicillin, and ciprofloxacin by pistachio shell powder coated with zinc oxide nanoparticles, arabian journal of chemistry (2019). [15] a.mohseni-bandpi, t. j . al-musawi, e. ghahramani, m. zarrabi, s.mohebi s.a., vahed, improvement of zeolite adsorption capacity for cephalexin by coating with magnetic fe3o4 nanoparticles. journal of molecular liquid, 218 (2016), 615–624. [16] n.dhiman, n. sharma, batch adsorption studies on the removal of ciprofloxacin hydrochloride from aqueous solution using zno nanoparticles and groundnut (arachis hypogaea) shell powder: a comparison. indian chemical engineer, (2018). 1–10. [17] z.liu, m. vatanakul, l. jia, y. i. n. g. zheng, hydrodynamics and mass transfer in gas‐liquid‐ solid circulating fluidized beds. chemical engineering & technology, 26(2003)1247-1253. [18] lan, q., bassi, a., zhu, j. x. j., & margaritis, a. (2002). continuous protein recovery from whey using liquid‐solid circulating fluidized bed ion exchange extraction. biotechnology and bioengineering, 78(2), 157-163. https://doi.org/10.31699/ijcpe.2019.3.5 https://doi.org/10.31699/ijcpe.2019.3.5 https://doi.org/10.31699/ijcpe.2019.3.5 https://doi.org/10.31699/ijcpe.2019.3.5 https://www.researchgate.net/publication/309845544_treating_of_oil-based_drill_cuttings_by_earthworms https://www.researchgate.net/publication/309845544_treating_of_oil-based_drill_cuttings_by_earthworms https://www.researchgate.net/publication/309845544_treating_of_oil-based_drill_cuttings_by_earthworms https://www.researchgate.net/publication/309845544_treating_of_oil-based_drill_cuttings_by_earthworms https://www.sciencedirect.com/science/article/abs/pii/s0169433214002645 https://www.sciencedirect.com/science/article/abs/pii/s0169433214002645 https://www.sciencedirect.com/science/article/abs/pii/s0169433214002645 https://www.sciencedirect.com/science/article/abs/pii/s0169433214002645 https://www.researchgate.net/profile/ayyad_al_shahwany2/publication/299410218_comparative_evaluation_of_alkaloids_extraction_methods_from_the_root_bark_of_punica_granatum_linn/links/56f4b1b408ae81582bf0a6ad.pdf https://www.researchgate.net/profile/ayyad_al_shahwany2/publication/299410218_comparative_evaluation_of_alkaloids_extraction_methods_from_the_root_bark_of_punica_granatum_linn/links/56f4b1b408ae81582bf0a6ad.pdf https://www.researchgate.net/profile/ayyad_al_shahwany2/publication/299410218_comparative_evaluation_of_alkaloids_extraction_methods_from_the_root_bark_of_punica_granatum_linn/links/56f4b1b408ae81582bf0a6ad.pdf https://www.researchgate.net/profile/ayyad_al_shahwany2/publication/299410218_comparative_evaluation_of_alkaloids_extraction_methods_from_the_root_bark_of_punica_granatum_linn/links/56f4b1b408ae81582bf0a6ad.pdf https://www.sciencedirect.com/science/article/pii/s1110016819300808 https://www.sciencedirect.com/science/article/pii/s1110016819300808 https://www.sciencedirect.com/science/article/pii/s1110016819300808 https://www.sciencedirect.com/science/article/pii/s1110016819300808 https://www.sciencedirect.com/science/article/pii/s1110016819300808 https://www.sciencedirect.com/science/article/abs/pii/s0043135407002539 https://www.sciencedirect.com/science/article/abs/pii/s0043135407002539 https://www.sciencedirect.com/science/article/abs/pii/s0043135407002539 https://www.sciencedirect.com/science/article/abs/pii/s0043135407002539 https://www.sciencedirect.com/science/article/abs/pii/s0043135407002539 https://www.sciencedirect.com/science/article/abs/pii/s0959652613004976 https://www.sciencedirect.com/science/article/abs/pii/s0959652613004976 https://www.sciencedirect.com/science/article/abs/pii/s0959652613004976 https://www.sciencedirect.com/science/article/abs/pii/s0959652613004976 https://www.sciencedirect.com/science/article/abs/pii/s0959652613004976 https://www.sciencedirect.com/science/article/pii/s0301479711001782 https://www.sciencedirect.com/science/article/pii/s0301479711001782 https://www.sciencedirect.com/science/article/pii/s0301479711001782 https://www.sciencedirect.com/science/article/pii/s0301479711001782 https://doi.org/10.31699/ijcpe.2018.4.1 https://doi.org/10.31699/ijcpe.2018.4.1 https://doi.org/10.31699/ijcpe.2018.4.1 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/248 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/248 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/248 https://pubs.acs.org/doi/abs/10.1021/es201121w https://pubs.acs.org/doi/abs/10.1021/es201121w https://pubs.acs.org/doi/abs/10.1021/es201121w https://pubs.acs.org/doi/abs/10.1021/es201121w https://pubs.acs.org/doi/abs/10.1021/es201121w https://www.sciencedirect.com/science/article/abs/pii/s0021979711009222 https://www.sciencedirect.com/science/article/abs/pii/s0021979711009222 https://www.sciencedirect.com/science/article/abs/pii/s0021979711009222 https://www.sciencedirect.com/science/article/abs/pii/s0021979711009222 https://www.sciencedirect.com/science/article/abs/pii/s0021979711009222 https://pubs.acs.org/doi/abs/10.1021/es801412j https://pubs.acs.org/doi/abs/10.1021/es801412j https://pubs.acs.org/doi/abs/10.1021/es801412j https://pubs.acs.org/doi/abs/10.1021/es801412j https://pubs.acs.org/doi/abs/10.1021/es801412j https://www.sciencedirect.com/science/article/pii/s1878535219301303 https://www.sciencedirect.com/science/article/pii/s1878535219301303 https://www.sciencedirect.com/science/article/pii/s1878535219301303 https://www.sciencedirect.com/science/article/pii/s1878535219301303 https://www.sciencedirect.com/science/article/pii/s1878535219301303 https://www.sciencedirect.com/science/article/pii/s1878535219301303 https://www.sciencedirect.com/science/article/abs/pii/s0167732215309296 https://www.sciencedirect.com/science/article/abs/pii/s0167732215309296 https://www.sciencedirect.com/science/article/abs/pii/s0167732215309296 https://www.sciencedirect.com/science/article/abs/pii/s0167732215309296 https://www.sciencedirect.com/science/article/abs/pii/s0167732215309296 https://www.sciencedirect.com/science/article/abs/pii/s0167732215309296 https://www.tandfonline.com/doi/abs/10.1080/00194506.2018.1424044 https://www.tandfonline.com/doi/abs/10.1080/00194506.2018.1424044 https://www.tandfonline.com/doi/abs/10.1080/00194506.2018.1424044 https://www.tandfonline.com/doi/abs/10.1080/00194506.2018.1424044 https://www.tandfonline.com/doi/abs/10.1080/00194506.2018.1424044 https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.200301844 https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.200301844 https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.200301844 https://onlinelibrary.wiley.com/doi/abs/10.1002/ceat.200301844 https://onlinelibrary.wiley.com/doi/abs/10.1002/bit.10171 https://onlinelibrary.wiley.com/doi/abs/10.1002/bit.10171 https://onlinelibrary.wiley.com/doi/abs/10.1002/bit.10171 https://onlinelibrary.wiley.com/doi/abs/10.1002/bit.10171 https://onlinelibrary.wiley.com/doi/abs/10.1002/bit.10171 s. l. kareem and a. a. mohammed / iraqi journal of chemical and petroleum engineering 21,3 (2020) 29 37 36 [19] j.mazumder, j. zhu, a. s. bassi, a. k. ray, modeling and simulation of liquid–solid circulating fluidized bed ion exchange system for continuous protein recovery. biotechnology and bioengineering, 104(2009) 111-126. doi.org/10.1002/bit.22368 [20] m.ersana, u. a. guler, u. acıkel, m.sarioglub, synthesis of hydroxyapatite/clay and hydroxyapatite/pumice composites for tetracycline removal from aqueous solutions, process safety and environmental protection 9(2015): 6 22–32 [21] p.chang, z. li, t.yu, s. munkhbayer, t. kuo, y.hung, j. jean, k.lin, sorptive removal of tetracycline from water by palygorskite, journal of hazardous material, 165(2009) 148–155. [22] a.a. mohammed, f. brouers, i.s. samaka, t.j. al-musawi, role of fe3o4 magnetite nanoparticles used to coat bentonite in zinc(ii) ions sequestration, environmental nanotechnology, monitoring & management, 10(2018) 17–27. [23] l.a. briens, n. ellis, hydrodynamics of threephase fluidised bed systems examined by statistical, fractal, chaos and wavelet analysis methods. chemical engineering science 60(2005) 6094–6106. [24] a. delebarre, j. m.morales, l.ramos, influence of bed mass on its fluidization characteristics,chemical engineering journal 98(2004) 81-88. [25] h.m.jena, hydrodynamics of gas-liquid-solid fluidized and semi-fluidized beds. phd. thesis, national institute of technology, rourkela. (2009). [26] a. a. mohammed, a.a. najim, t.j. al-musawi, a.i. alwared, "adsorptive performance of a mixture of three nonliving algae classes for nickel remediation in synthesized wastewater." journal of environmental health science and engineering 17, no. 2 (2019): 529-538. [27] j.h. al-baidhani, s. t. al-salihy, removal of heavy metals from aqueous solution by using low cost rice husk in batch and continuous fluidized experiments, international journal of chemical engineering and applications, 7(2016) 6-10 [28] m. loredo-cancino, e. soto-regalado, r. b. garcía-reyes, f. cerino-córdova j. de, m. t. garzagonzález, m. m. alcalá-rodríguez, n. e. dávilaguzmán (2014). adsorption and desorption of phenol onto barley husk-activated carbon in an airlift reactor. desalination and water treatment, 57(2), 845–860. [29] f. brouers, t.j. al-musawi, brouers-sotolongo fractal kinetics versus fractional derivative kinetics: a new strategy to analyze the pollutants sorption kinetics in porous materials. hazardous material ,350(2015)162-168. https://onlinelibrary.wiley.com/doi/abs/10.1002/bit.22368 https://onlinelibrary.wiley.com/doi/abs/10.1002/bit.22368 https://onlinelibrary.wiley.com/doi/abs/10.1002/bit.22368 https://onlinelibrary.wiley.com/doi/abs/10.1002/bit.22368 https://onlinelibrary.wiley.com/doi/abs/10.1002/bit.22368 https://doi.org/10.1002/bit.22368 https://www.sciencedirect.com/science/article/abs/pii/s0957582015000634 https://www.sciencedirect.com/science/article/abs/pii/s0957582015000634 https://www.sciencedirect.com/science/article/abs/pii/s0957582015000634 https://www.sciencedirect.com/science/article/abs/pii/s0957582015000634 https://www.sciencedirect.com/science/article/abs/pii/s0957582015000634 https://www.sciencedirect.com/science/article/abs/pii/s0304389408014349 https://www.sciencedirect.com/science/article/abs/pii/s0304389408014349 https://www.sciencedirect.com/science/article/abs/pii/s0304389408014349 https://www.sciencedirect.com/science/article/abs/pii/s0304389408014349 https://www.sciencedirect.com/science/article/abs/pii/s2215153218300011 https://www.sciencedirect.com/science/article/abs/pii/s2215153218300011 https://www.sciencedirect.com/science/article/abs/pii/s2215153218300011 https://www.sciencedirect.com/science/article/abs/pii/s2215153218300011 https://www.sciencedirect.com/science/article/abs/pii/s2215153218300011 https://www.sciencedirect.com/science/article/pii/s0009250905002952 https://www.sciencedirect.com/science/article/pii/s0009250905002952 https://www.sciencedirect.com/science/article/pii/s0009250905002952 https://www.sciencedirect.com/science/article/pii/s0009250905002952 https://www.sciencedirect.com/science/article/abs/pii/s1385894703002067 https://www.sciencedirect.com/science/article/abs/pii/s1385894703002067 https://www.sciencedirect.com/science/article/abs/pii/s1385894703002067 https://www.sciencedirect.com/science/article/abs/pii/s1385894703002067 http://ethesis.nitrkl.ac.in/1560/ http://ethesis.nitrkl.ac.in/1560/ http://ethesis.nitrkl.ac.in/1560/ https://link.springer.com/article/10.1007/s40201-019-00367-w https://link.springer.com/article/10.1007/s40201-019-00367-w https://link.springer.com/article/10.1007/s40201-019-00367-w https://link.springer.com/article/10.1007/s40201-019-00367-w https://link.springer.com/article/10.1007/s40201-019-00367-w https://link.springer.com/article/10.1007/s40201-019-00367-w https://www.researchgate.net/profile/jabbar_al-baidhani/publication/283241285_removal_of_heavy_metals_from_aqueous_solution_by_using_low_cost_rice_husk_in_batch_and_continuous_fluidized_experiments/links/5842f7c108ae8e63e623c1ff/removal-of-heavy-metals-from-aqueous-solution-by-using-low-cost-rice-husk-in-batch-and-continuous-fluidized-experiments.pdf https://www.researchgate.net/profile/jabbar_al-baidhani/publication/283241285_removal_of_heavy_metals_from_aqueous_solution_by_using_low_cost_rice_husk_in_batch_and_continuous_fluidized_experiments/links/5842f7c108ae8e63e623c1ff/removal-of-heavy-metals-from-aqueous-solution-by-using-low-cost-rice-husk-in-batch-and-continuous-fluidized-experiments.pdf https://www.researchgate.net/profile/jabbar_al-baidhani/publication/283241285_removal_of_heavy_metals_from_aqueous_solution_by_using_low_cost_rice_husk_in_batch_and_continuous_fluidized_experiments/links/5842f7c108ae8e63e623c1ff/removal-of-heavy-metals-from-aqueous-solution-by-using-low-cost-rice-husk-in-batch-and-continuous-fluidized-experiments.pdf https://www.researchgate.net/profile/jabbar_al-baidhani/publication/283241285_removal_of_heavy_metals_from_aqueous_solution_by_using_low_cost_rice_husk_in_batch_and_continuous_fluidized_experiments/links/5842f7c108ae8e63e623c1ff/removal-of-heavy-metals-from-aqueous-solution-by-using-low-cost-rice-husk-in-batch-and-continuous-fluidized-experiments.pdf https://www.researchgate.net/profile/jabbar_al-baidhani/publication/283241285_removal_of_heavy_metals_from_aqueous_solution_by_using_low_cost_rice_husk_in_batch_and_continuous_fluidized_experiments/links/5842f7c108ae8e63e623c1ff/removal-of-heavy-metals-from-aqueous-solution-by-using-low-cost-rice-husk-in-batch-and-continuous-fluidized-experiments.pdf https://www.tandfonline.com/doi/abs/10.1080/19443994.2014.970579 https://www.tandfonline.com/doi/abs/10.1080/19443994.2014.970579 https://www.tandfonline.com/doi/abs/10.1080/19443994.2014.970579 https://www.tandfonline.com/doi/abs/10.1080/19443994.2014.970579 https://www.tandfonline.com/doi/abs/10.1080/19443994.2014.970579 https://www.tandfonline.com/doi/abs/10.1080/19443994.2014.970579 https://www.sciencedirect.com/science/article/abs/pii/s0304389418300918 https://www.sciencedirect.com/science/article/abs/pii/s0304389418300918 https://www.sciencedirect.com/science/article/abs/pii/s0304389418300918 https://www.sciencedirect.com/science/article/abs/pii/s0304389418300918 https://www.sciencedirect.com/science/article/abs/pii/s0304389418300918 s. l. kareem and a. a. mohammed / iraqi journal of chemical and petroleum engineering 21,3 (2020) 29 37 37 ازالة التتراسايكلين من المياه الملوثة باستخدام االبراج المتميعة الدوارة 2و احمد عبد محمد 1صابرين لطيف كريم قسم التخطيط البيئي/جامعة الكوفة 1 البيئية/جامعة بغدادقسم الهندسة 2 الخالصة الزالة التتراسايكلين بنظام مستمرباستخدام قشور الفستق المطلية باوكسيد تم اعتماد برج االمتزازالمتيمع الدوار تأثيرات عوامل عدة بما في ذلك: معدل تدفق التتراسايكلين ،عمق ، وتم فحص الزنك النانوي كمادة مازة اسايكلين االولي ومعدل تدفق الهواء على منحني االنكسار والوقت المطلوب للحشوة الحشوة ، وتركيز التتر اضافة اوكسيد الزنك يؤدي الى زيادة المساحة السطحية والفراغات في المادة المازة .للوصول الى قابلية االمتزاز كفاءة االزالة ايضا يزداد مما يؤدي الى زيادة االمتزاز وايضا الوقت الالزم المطلوب للوصول الى حد االشباع تتحقق عند اقل تدفق للتراسايكلين ،اعلى ارتفاع للحشوة، اعلى تركيز للتتراسايكلين واعلى حد لتدفق الهواء. ايضا تم ايجاد عالقة رياضية للحد االدنى من سرعة التميع ووجد انها دالة من سرعة السائل ،حجم حيبات كثافة الجسيمات . ايضا برج االمتزاز المتميع الدوار يحقق اداء افضل بزيادة المادة المازة ، عمق الحشوة وايضا الوقت الالزم لالشباع بحدود ساعتين مقارنة ببرج التميع التقليدي. الكلمات الدالة: تيتراسايكلين, سرعة التميع الصغرى, منحنى االختراق available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.21 no.2 (june 2020) 15 – 23 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: teba h. mhawesh , email: eng.teba94@yahoo.com , name: ziad t. abd ali, email: z.teach2000@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. reuse of brick waste as a cheap-sorbent for the removal of nickel ions from aqueous solutions teba h. mhawesh and ziad t. abd ali university of baghdad/ college of engineering/ environmental engineering, baghdad iraq abstract the potential application of granules of brick waste (gbw) as a low-cost sorbent for removal of ni +2 ions from aqueous solutions has been studied. the properties of gbw were determined through several tests such as x-ray diffraction (xrd), energy dispersive x-ray (edx), scanning electron microscopy (sem), and bet surface area. in batch tests, the influence of several operating parameters including contact time, initial concentration, agitation speed, and the dose of gbw was investigated. the best values of these parameters that provided maximum removal efficiency of nickel (39.4%) were 1.5 hr, 50 mg/l, 250 rpm, and 1.8 g/100ml, respectively. the adsorption data obtained by batch experiments subjected to the three isotherm models called langmuir, freundlich and elovich, the results showed that the freundlich isotherm model described well the sorption data (r 2 =0.9176) in comparison with other models. the kinetic data were analyzed using two kinetic models called pseudo-first-order and pseudo-second-order. the pseudo-first-order kinetic model was found to agree well with the experimental data. keywords: sorption, ni +2 , brick waste, isotherms, kinetics, wastewater received on 13/10/2019, accepted on 18/02/2020, published on 30/06/2020 https://doi.org/10.31699/ijcpe.2020.2.3 1introduction many branches of industry nowadays generate large quantities of wastewater containing toxic and carcinogenic organic and inorganic compounds. heavy metals are considered inorganic pollutants such as mercury, cadmium, lead, cobalt, zinc, nickel, manganese etc. it’s not decomposed so their metal concentrations should be at minimum to reasonable levels before drain into their environment, [1]. nickel metals are danger and toxic to humans, it's represent a serious environmental issue, [2]. nickel exists in the effluents of storage battery industries; desalinate plants, gas turbines, coinage, and costume jewelry, [3]. the us environmental protection agency )epa) requires nickel metals not to exceed 0.015 mg/l in drinking water ,[4]. above the permissible limit may cause adverse health impacts such as anemia, diarrhea , hepatitis, the damages of lungs and kidney and pulmonary fibrosis,[5];[2]. accordingly, many methods have been studied to remove toxic metal ions from industrial wastewater include, chemical-precipitation, ion-exchange, biosorption , reverse-osmosis, floatation, and sorption etc. [2], [6]. several sorbents can be utilized for removal of toxic metals from wastewater but porous carbons sorbent are utilized extensively in contrast with other methods because these sorbents have a large specific, high sorption capacity, and easily regenerated, but is considered an expensive sorbent material. for that reason, different cheap materials like: zeolites, [7], metal oxides, [8], iron oxide-coated sand, [9], and clay minerals, [10], had recently been examined with the purpose to demonstrate their capacity for heavy metal removal from pollutants wastewater. but, the solution of specific water issues encountered in communities of developing countries had required the elaboration of proven and locally more suitable water handling procedures at low costs, [11]. in the recent years, the ability of brick waste utilized as a cheap sorbent to remove soluble heavy metal pollutants from wastewaters had been studied, [12, [13]. the nature of brick material, surface area, and surface charge influence the extent of interaction with metal ions. as brick granules are negatively charged, therefore cations will be strongly attached to brick granules [14]. based on the above mentioned concepts, the purpose of this study is to use brick waste as a cheap and abundant material to remove nickel ions from aqueous solutions. the influence of contact time, initial concentration of ni +2 , agitation speed, and sorbent mass on the removal percent of nickel ions were studied. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:eng.teba94@yahoo.com mailto:z.teach2000@yahoo.com http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2020.2.3 t. h. mhawesh and z. t. abd ali / iraqi journal of chemical and petroleum engineering 21,2 (2020) 15 23 16 2experimental work 2.1. granules of brick waste (gbw) preparation pieces of brick waste, which are left unused after construction, were used as sorbent in this study. it were crushed and sieved with size ranging from (1.18) mm to (1.7) mm. the obtained granules of gbw were washed several times with distilled water then dried as shows in fig. 1. fig. 1. granules of brick waste (gbw) 2.2. characterization of gbw a. surface area surface area is an important factor in determining the active sites that will be occupied with the contaminants. therefore, increasing the surface area of the material increases its susceptibility to adsorb more quantity of pollutants. the bet surface area was measured using (quanta chrome, usa), at the petroleum research and development center/ ministry of oil / baghdad iraq. b. x-ray diffraction (xrd) analysis the surface qualitative analysis was carried out to characterize and confirm the existence of the major components; samples were analyzed before uptake of nickel. this analysis was accomplished using (bruker, d2 phaser, germany). c. energy dispersive x-ray (edx) analysis edx analysis is a chemical microanalysis technique utilized in conjunction with scanning electron microscopy (sem).it’s used to recognize the elemental composition of materials. this test carried out using ( tescan,vega iii , czech republic). d. scanning electron microscopy (sem) scanning electron microscope (tescan, vega iii, and czech republic) was utilized for the surface studies of gbw. using the optimized conditions for the sorption of nickel ions, the loaded mass was filtered, washes and dried at 105 o c for 30 min. unloaded mass was also subject to the same circumstances and both the loaded and unloaded mass was subjected to sem to identify the changes on the surface of the gbw before and after loading by the nickel ions molecules. 2.3 preparation of synthetic wastewater the synthetic solution of nickel with a concentration of 1000 mg/l was prepared by dissolving a 4.95 g of of nickel nitrate (ni(no3).6h20) in 1 l of distilled water and this synthetic solution was ph adjusted using 0.1 m of ( hno3 ) and/or (naoh ) as required. 2.4 sorption experiments these experiments were carried out to identify the better conditions of contact time, , initial concentration of contaminant, agitation speed and dosage of sorbent. a number of flasks of (250 ml) are employed and each one is filled with 100 ml of ni 2+ ions solution which has initial concentration of (50 mg/l ), initial ph= 4 and about (1g/100ml) of sorbent(gbw) was added into each flask .the flasks were preserved stirred in (200 rpm) speed orbital shaker at ambient temperature. then the gbw was separated from the pollutant solution by filtration. these tests were conducted at different time (10,20,30,50,70,90,150,180,240 min.), initial concentrations (50, 100,150,200,250 mg/l ) , agitationspeeds (0, 50, 100, 150, 200 and 250 rpm),and sorbent dosages (0.2, 0.4, 0.6, 0.8,1,1.1,1.2,1.3,1.5,1.8 and 2 g/100ml). the metal ion concentration at saturation was calculated by atomic absorption spectrometry (shimadzu, japan). the concentration of metal ion sorbed by gbw was calculated from the difference between the initial and ,the final concentration of metal ions solution obtained before and after contact between the gbw and the synthetic ni +2 solution. the sorption capacities were determined using eq. (1) [15]: 𝑞𝑒 = (𝐶𝑜−𝐶𝑒)𝑉 𝑚 (1) where: qe is the amount of sorbed nickel ion, per unit mass of gbw (mg/g), co and ce are the initial and equilibrium concentrations of nickel in the solution (mg/l), v is the volume of solution (l), and m is the mass of the sorbent gbw (g).the removal efficiency (r%) of the ni +2 was calculated using eq. (2), [15]: 𝑅% = 𝐶𝑜−𝐶𝑒 𝐶𝑜 𝑥100 (2) t. h. mhawesh and z. t. abd ali / iraqi journal of chemical and petroleum engineering 21,2 (2020) 15 23 17 3isotherm models in the current study, three isotherm models is used to simulate the performance of gbw in removing nickel ions from wastewater. a summary of these models is presented below:  langmuir model: assumes a surface with homogeneous binding sites, equivalent sorption energies, and no interactions between sorbed species, [16] . the linear form of this model can be written as follows: 𝐶𝑒 𝑞𝑒 = 𝐶𝑒 𝑞𝑚𝑎𝑥 + 1 𝑞𝑚𝑎𝑥 𝐾l (3) where: qmax ,is the maximum sorption capacity (mg/g). kl, is the langmuir sorption constant (l/mg). ce , is the concentration (mg/l) of ni +2 in solution at equilibrium. the plot of (ce/qe) against (ce) gives a straight line with a slope and intercept of (1/qmax) and (1/qmax kl) respectively.  freundlich model: it’s an empirical model not limited to monolayer coverage alone but also describe multilayer adsorption, [16]. it is expressed linearly as in eq.4: ln qe = 1 n ln ce + ln kf (4) where: kf, is the freundlich sorption constant. ce, is the concentration (mg/l) of ni +2 in solution at equilibruim. n, is an empirical constant indicative of the intensity of the sorption. the plots of (log qe) against, (log ce), gives a linear graph with slope 1/n and intercept log kf from which n and kf can be determined respectively.  elovich model: is based on a kinetic principle assuming that the sorption effective sites increase exponentially with sorption, which implies a multilayer sorption, [17], [18]. it can be expressed as: 𝑙𝑛 𝑞𝑒 𝐶𝑒 = 𝑙𝑛𝐾𝐸 𝑞𝑚 − 𝑞𝑒 𝑞𝑚 (5) where: ke is the elovich equilibrium constant (l/mg) and qm is the elovich maximum adsorption capacity (mg/g). 4kinetic models kinetic sorption models are helpful to understand the mechanism of the sorption process of nickel onto gbw. these models include pseudo first order and pseudosecond order, [19].  the pseudo-first order kinetic rate equation is : 𝑙𝑛(𝑞𝑒 − 𝑞𝑡) = 𝑙𝑛(𝑞𝑒) − 𝐾1𝑡 (6) where: qe and qt, represent the amounts of metal ion (ni +2 ) sorbed per unit mass of gbw at equilibrium (mg/g) , and time t (min), respectively. k1, is the rate constant of pseudo_ first _ order sorption (1/min). the pseudo_second_order kinetics rate equation is: 𝑡 𝑞𝑡 = 1 𝐾2 𝑞𝑒 2 + 𝑡 𝑞𝑒 (7) where: k2, is the rate constant of pseudo_second_order sorption (g / mg. min). 5results and discussion 5.1. characterization of gbw a. xrd analysis the xrd measurement was performed to identify the mineralogical composition of gbw. fig. 2 illustrates that gbw was composed mainly of diopside (29.9%), quartz (22.4%), wollastonit (22.2%), akermente (20.5%) and mellite (5%). diopside originating from dolomite (cao, mgo, 2co2), also explain that (quartz) and (calcite) are the most popular compounds, with the addition of clays and clay minerals. however, due to the application of high temperature handling through the manufacturing process, the decomposition of clay minerals forming ( sio2 ) compound, which followed by the loss of their crystal structure. caco3 compound decompose and resulting cao compound that may react with the clay resulting calcium-silicate called wollastonite [20]. fig. 2. xrd of gbw t. h. mhawesh and z. t. abd ali / iraqi journal of chemical and petroleum engineering 21,2 (2020) 15 23 18 b. edx analysis the edx analysis was carried out and the spectra are given in fig. 3. this figure indicates that the gbw composed of oxygen, calcium ,silicon , aluminium , iron , magnesium, sodium, potassium and sulfur, with percentage of 44.2%, 21.7%, 18.1%, 5.7%,5%, 2.8%, 1.4%, 0.6% and 0.6% , respectively. the analysis for gbw showed the presence of oxygen , calcium, silicon , and other small percentages of metals .the existence of these oxides and hydroxides in gbw because its having a various (higher) sorption capacity , [21] . fig. 3. edx spectra of gbw c. sem analysis the sem analysis images at 50 mm gained before/after sorption to identify the surface morphology. fig. 4 (a) represents the sem spectra of the gbw before nickel loading, its shows irregular structure having small pores, which simplify the process of sorption. the sem analysis after nickel sorption indicates that these pores become filled with nickel ions as shown in fig. 4 (b) [21]. (a) (b) fig. 4. sem spectra of the of gbw (a) before and (b) after nickel ions loading d. surface area the results of this test clarify that the gbw sample show a low bet surface area of (1m 2 / g).this results in a good agreement with previous study of kooli [22]. 5.2. influence of batch operating parameters a. effect of contact time the impact of the contact time on sorption of ni +2 using gbw was studied by using contaminated aqueous solution with initial nickel concentration 50(mg/l) at ph=4. the relation between the contact time and removal efficiency of nickel ions is shown in fig.5,the best removal efficiency (28%) was reached within about 90(min). the sorption of ni +2 ions occurred in two phase, an initial rapid sorption followed by subsequent slow sorption. the sorption process appeared to proceed rapidly when the numbers of active sites are much higher than the number of metal species to be sorbed, [23]. the increase of solution ph during the contact with gbw can be attributed to the dissolution of some of their components, [20]. fig. 5. effect of contact time on ni +2 removal percent (co = 50 mg/l, ph= 4, agitation speed = 200 rpm, and mass of gbw = 1g /100ml) t. h. mhawesh and z. t. abd ali / iraqi journal of chemical and petroleum engineering 21,2 (2020) 15 23 19 b. effect of initial concentration the initial metal ions concentration is a very important factor to be investigated in sorption studies as most contaminated wastewaters usually present different concentrations of metal ions, so determination of its effect is necessary for an elaborate sorption study, [24]. the effect of initial metal ion concentration on the percentage removal of ni +2 ions using gbw is shown in fig. 6. the percentage removal of metal ions decreased with increase in the initial metal concentration from 50 to 250 mg/l. a decrease from 28% to 9 % of ni +2 ions was obtained. this decrease is due to the fact that the sorbent material (gbw) has a fixed number of active sites and at higher concentrations, the active sites become saturated, [25] the simple hydrolysis of generality divalent metal ions can be written as follows: m +2 +h2o⇌m(oh) + +h + (8) where: m +2 is ni +2 or any metal ions. the final ph increase when the concentration of the solution decreases. this happens when gbw is being occupied by ni +2 ions, the reaction above shifts to the left, leading to the depletion of protons and hence rise in ph, [26] fig. 6. effect of initial concentration on ni +2 removal percent (time= 90 min., ph= 4, agitation speed = 200 rpm, and mass of gbw = 1g /100ml) c. effect of agitation speed the effect of agitation speed of the sorbent/sorbate system was monitored at (0, 50, 100, 150, 200, and 250 rpm) as shown in fig.7.the significant increase in sorption is primarily due to the fact that agitation speed facilitates proper contact between ni +2 ions in solution and the gbw effective sites and consequently promoting better transfer of sorbate ions (ni +2 ) to the sorbent sites, [27].in addition, the increase of the ph of the solution during the contact with gbw can be attributed to the dissolution of some gbw components as reported by jelić ,[20]. fig. 7. effect of agitation speed on ni +2 removal percent (co = 50 mg/l, time=150 min, ph=4, and mass of gbw = 1g /100ml) d. effect of the dose of gbw the study of the mass of gbw that utilized for the removal of ni +2 ions, was carried out using the various dosage of gbw range from (0.2 2) g. the effect of sorbent dose on the sorption of nickel by gbw was presented in fig. 8. as illustrated in fig.8, the nickel removal percent increased with increase of sorbent dose. the increase in the gbw dosage improved the availability of more effective sites for the sorption, thus making easier penetration of nickel ions to the sorption sites, [23]. moreover, the final ph increase due to release the amounts of dissolved ca +2 and other light metal alkalis in solution during the reaction between gbw and ni +2 ions, [20]. fig. 8. effect of sorbent dose on ni +2 removal percent (co = 50 mg/l, ph= 4, time= 90 min, and mass of gbw = 1g /100ml) 5.3. sorption isotherms the sorption data for nickel is fitted with linearized equations of three isotherm models namely; langmuir, freundlich and elovich. -1 1 3 5 7 9 0 20 40 60 80 100 0 0.5 1 1.5 2 f in a l p h r e m o va l % mass of sorbent (g) ni… t. h. mhawesh and z. t. abd ali / iraqi journal of chemical and petroleum engineering 21,2 (2020) 15 23 20 accordingly, the empirical coefficients for each model were determined from the slope and intercept of linear plot using microsoft excel 2013 software. the isotherm graphical representations of these three models are shown in fig. 9. all constants are presented in table 1. the value of r 2 close to 1 denotes that the respective equation a good fits the experimental data, [27]. so, the freundlich isotherm model was concluded to be preferred isotherms models for the experimental data. (a) (b) (c) fig. 9. isotherm models plot: a. langmuir isotherm model, b. freundlich isotherm model, c. elevich isotherm model table 1. sorption isotherm constants with coefficients of determination for ni +2 onto gbw isotherm model parameters gbw langmuir qm (mg/g) -1.69 b (l/mg) -0.014 r 2 0.5784 freundlich kf (l/mg) 0.00247 n 0.547 r 2 0.9176 elovich qm (mg/g) -3.07 ke (l/mg) -0.00874 r 2 0.8437 5.4. kinetic study to identify the type of sorption mechanism occurs, the kinetic equations namely pseudo-first -order and pseudosecond order were utilized. it is clear from fig. 10 and table 2 that the reaction for gbw is pseudo-first -order because the value of the experimental qe was the closest to the qe calculated from the pseudo-first -order in compared with the pseudo-second order model, irrespective to the amount of the correlation coefficient (r 2 ), so that the mechanisms will be physical sorption [29]. (a) (b) fig. 10. the kinetic models for sorption ni +2 onto gbw: a. pseudo-first order reaction model, b. pseudo-secondorder reaction model t. h. mhawesh and z. t. abd ali / iraqi journal of chemical and petroleum engineering 21,2 (2020) 15 23 21 table 2. the kinetic constants for the sorption of ni +2 onto qe (exp) (mg/g) pseudofirst order pseudosecond – order 1.153 k1(1/min) qe (calc.) (mg/g) r 2 0.0323 1.11 0.9886 k2 (g/mg*min) qe(calc.) (mg/g) r 2 0.024 1.42 0.9926 6conclusions based on the results obtained from the experimental work, the following conclusions can be drawn:  the granules of brick waste (gbw) material proved low effectiveness in removing nickel ions from aqueous solutions with removal percent of 39.4% at dose value of 1.8 sorbent according to the experimental conditions .  the batch results indicated that several parameters including contact time, initial concentration, agitation speed, and granular brick waste dose affect the sorption process. the optimum values of these factors which provided maximum removal percent ( 39.4%) of nickel with initial ph of 4 were 90 min, 50 mg/l, 250rpm, and 1.8/100ml, respectively. the maximum sorption capacity for gbw (1.153mg/g (  the isotherm study refers that the sorption data correlated well with freundlich isotherm model which showed the highest value of the correlation coefficient (r 2 = 0.9176)  the kinetic study showed that the pseudo-first -order kinetic model was conform better than pseudo-second order model kinetic model. this result clarify that physical sorption have been predominant in the sorption of ni +2 ions using gbw. references [1] a. h., sulaymon, b. a., abid, & j. a., al-najar "removal of lead copper chromium and cobalt ions onto granular activated carbon in batch and fixed-bed adsorbers." chemical engineering journal 155.3 (2009): 647-653. [2] f. h. kamar al-hamadani, “removal of nickel ions using a biosorbent bed (laminaria saccharina) algae”, ijcpe, vol. 13, no. 4, pp. 47-55, dec. 2012. [3] p. v., hemalatha, & p. v. v. , prasada rao. "adsorption batch studies on calcined brick powder in removing chromium and nickel ions." international journal advanced research in chemistry science 1.6 (2014): 14-21. [4] y., hannachi, & a. , hannachi. "the efficiency of the flotation technique for the removal of nickel ions from aqueous solution." desalination and water treatment 6.1-3 (2009): 299-306. [5] m. a., abdullah, & a. d. , prasad. "biosorption of nickel (ii) from aqueous solutions and electroplating wastewater using tamarind (tamarindus indica l.) bark. ," australian journal of basic and applied sciences 4.8 (2010): 3591-3601. [6] m., hunsom, k., pruksathorn, s., damronglerd, h., vergnes, & p., duverneuil. "electrochemical treatment of heavy metals (cu2+, cr6+, ni2+) from industrial effluent and modeling of copper reduction." water research 39.4 (2005): 610-616. [7] w., qiu, & y. zheng, "removal of lead, copper, nickel, cobalt, and zinc from water by a cancrinitetype zeolite synthesized from fly ash." chemical engineering journal 145.3 (2009): 483-488. [8] f., chang, j., qu, r., liu, x., zhao, & p., lei. "practical performance and its efficiency of arsenic removal from groundwater using fe-mn binary oxide." journal of environmental sciences 22.1 (2010): 1-6. [9] n., boujelben, j., bouzid, & z. , elouear. "adsorption of nickel and copper onto natural iron oxide-coated sand from aqueous solutions: study in single and binary systems." journal of hazardous materials 163.1 (2009): 376-382. [10] m. q., jiang, x. y., jin, x. q., lu, & z. l. , chen. "adsorption of pb (ii), cd (ii), ni (ii) and cu (ii) onto natural kaolinite clay." desalination 252.1-3 (2010): 33-39. [11] s. c. , dehou, m., wartel, p., recourt, b., revel, j., mabingui, a., montiel, & a. ,boughriet "physicochemical, crystalline and morphological characteristics of bricks used for ground waters purification in bangui region (central african republic)." applied clay science 59 (2012): 69-75. [12] h. a., aziz, m. n., adlan, & k. s., ariffin. "heavy metals (cd, pb, zn, ni, cu and cr (iii)) removal from water in malaysia: post treatment by high quality limestone." bioresource technology 99.6 (2008): 1578-1583. [13] r., djeribi, & o. , hamdaoui. "sorption of copper (ii) from aqueous solutions by cedar sawdust and crushed brick." desalination 225.1-3 (2008): 95112. [14] n., priyantha, & a. , bandaranayaka. "interaction of cr (vi) species with thermally treated brick clay." environmental science and pollution research 18.1 (2011): 75-81. [15] a. r., kul, & h., koyuncu. "adsorption of pb (ii) ions from aqueous solution by native and activated bentonite: kinetic, equilibrium and thermodynamic study." journal of hazardous materials 179.1-3 (2010): 332-339. [16] a. a., inyinbor, f. a., g. a. adekola, & olatunji. "kinetics, isotherms and thermodynamic modeling of liquid phase adsorption of rhodamine b dye onto raphia hookerie fruit epicarp." water resources and industry 15 (2016): 14-27. https://www.sciencedirect.com/science/article/abs/pii/s1385894709005932 https://www.sciencedirect.com/science/article/abs/pii/s1385894709005932 https://www.sciencedirect.com/science/article/abs/pii/s1385894709005932 https://www.sciencedirect.com/science/article/abs/pii/s1385894709005932 https://www.sciencedirect.com/science/article/abs/pii/s1385894709005932 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/344 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/344 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/344 http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.674.6619&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.674.6619&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.674.6619&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.674.6619&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.674.6619&rep=rep1&type=pdf https://www.tandfonline.com/doi/abs/10.5004/dwt.2009.553 https://www.tandfonline.com/doi/abs/10.5004/dwt.2009.553 https://www.tandfonline.com/doi/abs/10.5004/dwt.2009.553 https://www.tandfonline.com/doi/abs/10.5004/dwt.2009.553 https://www.cabdirect.org/cabdirect/abstract/20103359630 https://www.cabdirect.org/cabdirect/abstract/20103359630 https://www.cabdirect.org/cabdirect/abstract/20103359630 https://www.cabdirect.org/cabdirect/abstract/20103359630 https://www.cabdirect.org/cabdirect/abstract/20103359630 https://www.sciencedirect.com/science/article/abs/pii/s0043135404005160 https://www.sciencedirect.com/science/article/abs/pii/s0043135404005160 https://www.sciencedirect.com/science/article/abs/pii/s0043135404005160 https://www.sciencedirect.com/science/article/abs/pii/s0043135404005160 https://www.sciencedirect.com/science/article/abs/pii/s0043135404005160 https://www.sciencedirect.com/science/article/abs/pii/s1385894708002532 https://www.sciencedirect.com/science/article/abs/pii/s1385894708002532 https://www.sciencedirect.com/science/article/abs/pii/s1385894708002532 https://www.sciencedirect.com/science/article/abs/pii/s1385894708002532 https://www.sciencedirect.com/science/article/abs/pii/s100107420960067x https://www.sciencedirect.com/science/article/abs/pii/s100107420960067x https://www.sciencedirect.com/science/article/abs/pii/s100107420960067x https://www.sciencedirect.com/science/article/abs/pii/s100107420960067x https://www.sciencedirect.com/science/article/abs/pii/s100107420960067x https://www.sciencedirect.com/science/article/abs/pii/s100107420960067x https://www.sciencedirect.com/science/article/abs/pii/s0304389408010042 https://www.sciencedirect.com/science/article/abs/pii/s0304389408010042 https://www.sciencedirect.com/science/article/abs/pii/s0304389408010042 https://www.sciencedirect.com/science/article/abs/pii/s0304389408010042 https://www.sciencedirect.com/science/article/abs/pii/s0304389408010042 https://www.sciencedirect.com/science/article/abs/pii/s0011916409012806 https://www.sciencedirect.com/science/article/abs/pii/s0011916409012806 https://www.sciencedirect.com/science/article/abs/pii/s0011916409012806 https://www.sciencedirect.com/science/article/abs/pii/s0011916409012806 https://www.sciencedirect.com/science/article/abs/pii/s0169131712000592 https://www.sciencedirect.com/science/article/abs/pii/s0169131712000592 https://www.sciencedirect.com/science/article/abs/pii/s0169131712000592 https://www.sciencedirect.com/science/article/abs/pii/s0169131712000592 https://www.sciencedirect.com/science/article/abs/pii/s0169131712000592 https://www.sciencedirect.com/science/article/abs/pii/s0169131712000592 https://www.sciencedirect.com/science/article/abs/pii/s0960852407003239 https://www.sciencedirect.com/science/article/abs/pii/s0960852407003239 https://www.sciencedirect.com/science/article/abs/pii/s0960852407003239 https://www.sciencedirect.com/science/article/abs/pii/s0960852407003239 https://www.sciencedirect.com/science/article/abs/pii/s0960852407003239 https://d1wqtxts1xzle7.cloudfront.net/50010803/sorption_of_copperii_from_aqueous_solu20161031-6559-1a7x5e2.pdf?1477935893=&response-content-disposition=inline%3b+filename%3dsorption_of_copper_ii_from_aqueous_solut.pdf&expires=1593190538&signature=fna11o5fn7~agnn3wdw0swepnbjvu-f7cnungjzma7fcsvx~h6muonruqhpbg8wthunbvoreuajeucdf0o~ssng0cpfhvf9jhivxpbfrz3syqhgiymmgvs950bxl7cx4lfxmjsebq3r8tocm8khtnjyt1jat2hhrbl7rwxc9kkd0a5bgokdiv4l5f1oda2n64dvsssfl~5ffqozy3frr9pul~rn3kk2misqbtd8iokzayfyxo7kbrdat75y4aeza9u2m-va77r6haq8vccfpuqzrpbzhytagqm9mcsfeltfull30pv3t7qfihlexomvm-igabmucxxqdoqszip-uvg__&key-pair-id=apkajlohf5ggslrbv4za 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https://d1wqtxts1xzle7.cloudfront.net/50010803/sorption_of_copperii_from_aqueous_solu20161031-6559-1a7x5e2.pdf?1477935893=&response-content-disposition=inline%3b+filename%3dsorption_of_copper_ii_from_aqueous_solut.pdf&expires=1593190538&signature=fna11o5fn7~agnn3wdw0swepnbjvu-f7cnungjzma7fcsvx~h6muonruqhpbg8wthunbvoreuajeucdf0o~ssng0cpfhvf9jhivxpbfrz3syqhgiymmgvs950bxl7cx4lfxmjsebq3r8tocm8khtnjyt1jat2hhrbl7rwxc9kkd0a5bgokdiv4l5f1oda2n64dvsssfl~5ffqozy3frr9pul~rn3kk2misqbtd8iokzayfyxo7kbrdat75y4aeza9u2m-va77r6haq8vccfpuqzrpbzhytagqm9mcsfeltfull30pv3t7qfihlexomvm-igabmucxxqdoqszip-uvg__&key-pair-id=apkajlohf5ggslrbv4za https://link.springer.com/article/10.1007/s11356-010-0358-3 https://link.springer.com/article/10.1007/s11356-010-0358-3 https://link.springer.com/article/10.1007/s11356-010-0358-3 https://link.springer.com/article/10.1007/s11356-010-0358-3 https://www.sciencedirect.com/science/article/abs/pii/s0304389410003158 https://www.sciencedirect.com/science/article/abs/pii/s0304389410003158 https://www.sciencedirect.com/science/article/abs/pii/s0304389410003158 https://www.sciencedirect.com/science/article/abs/pii/s0304389410003158 https://www.sciencedirect.com/science/article/abs/pii/s0304389410003158 https://www.sciencedirect.com/science/article/pii/s221237171630052x https://www.sciencedirect.com/science/article/pii/s221237171630052x https://www.sciencedirect.com/science/article/pii/s221237171630052x https://www.sciencedirect.com/science/article/pii/s221237171630052x https://www.sciencedirect.com/science/article/pii/s221237171630052x t. h. mhawesh and z. t. abd ali / iraqi journal of chemical and petroleum engineering 21,2 (2020) 15 23 22 [17] n., ayawei, a. n., ebelegi, & d. , wankasi. "modelling and interpretation of adsorption isotherms." journal of chemistry 2017 (2017). [18] a. h., sulaymon, a. a., faisal, & z. t. , abd ali "performance of granular dead anaerobic sludge as permeable reactive barrier for containment of lead from contaminated groundwater." desalination and water treatment 56.2 (2015): 327-337. [19] s. s., gupta, & k. g. , bhattacharyya. "kinetics of adsorption of metal ions on inorganic materials: a review." advances in colloid and interface science 162.1-2 (2011): 39-58. [20] i., jelić, m., šljivić-ivanović, s., dimović, d., antonijević, m., jović, m., mirković, & i., smičiklas. "the applicability of construction and demolition waste components for radionuclide sorption." journal of cleaner production 171 (2018): 322-332. [21] s., hussain, s., gul, s., khan, h. u., rehman, m., ishaq, a. , khan, & z. u. din. "removal of cr (vi) from aqueous solution using brick kiln chimney waste as adsorbent." desalination and water treatment 53.2 (2015): 373-381. [22] f., kooli, l., yan, r., al-faze, & a., alsehimi. "removal enhancement of basic blue 41 by brick waste from an aqueous solution." arabian journal of chemistry 8.3 (2015): 333-342. [23] h., panda, n., tiadi, m., mohanty & c. r. mohanty "studies on adsorption behavior of an industrial waste for removal of chromium from aqueous solution." south african journal of chemical engineering 23 (2017): 132-138 [24] k. g., akpomie, f. a., dawodu, & k. o. , adebowale "mechanism on the sorption of heavy metals from binary-solution by a low cost montmorillonite and its desorption potential." alexandria engineering journal 54.3 (2015): 757767. [25] m., martinez, n., miralles, s., hidalgo, n., fiol, i., villaescusa, & j. , poch. "removal of lead (ii) and cadmium (ii) from aqueous solutions using grape stalk waste." journal of hazardous materials 133.1-3 (2006): 203-211. [26] m., horsfall jnr, & a. i. spiff. "studies on the effect of ph on the sorption of pb2+ and cd2+ ions from aqueous solutions by caladium bicolor (wild cocoyam) biomass." electronic journal of biotechnology 7.3 (2004): 14-15. [27] m. a. o., badmus, t. o. k., audu, & b. u. , anyata. "removal of lead ion from industrial wastewaters by activated carbon prepared from periwinkle shells (typanotonus fuscatus)." turkish journal of engineering and environmental sciences 31.4 (2007): 251-263. [28] p. s., kumar, & r. , gayathri. "adsorption of pb2+ ions from aqueous solutions onto bael tree leaf powder: isotherms, kinetics and thermodynamics study." journal of engineering science and technology 4.4 (2009): 381-399. [29] l. c., edomwonyi-otu, s. o., gabor, o. a., idowu, & s. g. ,bawa "kinetics of adsorption of nickel ion on kankara kaolinite" leonardo electronic journal of practices and technologies 22 (2013): 83-92. https://www.hindawi.com/journals/jchem/2017/3039817/ https://www.hindawi.com/journals/jchem/2017/3039817/ https://www.hindawi.com/journals/jchem/2017/3039817/ https://www.tandfonline.com/doi/abs/10.1080/19443994.2014.942376 https://www.tandfonline.com/doi/abs/10.1080/19443994.2014.942376 https://www.tandfonline.com/doi/abs/10.1080/19443994.2014.942376 https://www.tandfonline.com/doi/abs/10.1080/19443994.2014.942376 https://www.tandfonline.com/doi/abs/10.1080/19443994.2014.942376 https://www.sciencedirect.com/science/article/pii/s0001868611000030 https://www.sciencedirect.com/science/article/pii/s0001868611000030 https://www.sciencedirect.com/science/article/pii/s0001868611000030 https://www.sciencedirect.com/science/article/pii/s0001868611000030 https://www.sciencedirect.com/science/article/abs/pii/s0959652617322242 https://www.sciencedirect.com/science/article/abs/pii/s0959652617322242 https://www.sciencedirect.com/science/article/abs/pii/s0959652617322242 https://www.sciencedirect.com/science/article/abs/pii/s0959652617322242 https://www.sciencedirect.com/science/article/abs/pii/s0959652617322242 https://www.sciencedirect.com/science/article/abs/pii/s0959652617322242 https://www.tandfonline.com/doi/abs/10.1080/19443994.2013.837001 https://www.tandfonline.com/doi/abs/10.1080/19443994.2013.837001 https://www.tandfonline.com/doi/abs/10.1080/19443994.2013.837001 https://www.tandfonline.com/doi/abs/10.1080/19443994.2013.837001 https://www.tandfonline.com/doi/abs/10.1080/19443994.2013.837001 https://www.sciencedirect.com/science/article/pii/s1878535214000719 https://www.sciencedirect.com/science/article/pii/s1878535214000719 https://www.sciencedirect.com/science/article/pii/s1878535214000719 https://www.sciencedirect.com/science/article/pii/s1878535214000719 https://www.sciencedirect.com/science/article/pii/s1026918516300920 https://www.sciencedirect.com/science/article/pii/s1026918516300920 https://www.sciencedirect.com/science/article/pii/s1026918516300920 https://www.sciencedirect.com/science/article/pii/s1026918516300920 https://www.sciencedirect.com/science/article/pii/s1026918516300920 https://www.sciencedirect.com/science/article/pii/s1110016815000423 https://www.sciencedirect.com/science/article/pii/s1110016815000423 https://www.sciencedirect.com/science/article/pii/s1110016815000423 https://www.sciencedirect.com/science/article/pii/s1110016815000423 https://www.sciencedirect.com/science/article/pii/s1110016815000423 https://www.sciencedirect.com/science/article/pii/s1110016815000423 https://www.sciencedirect.com/science/article/abs/pii/s0304389405006370 https://www.sciencedirect.com/science/article/abs/pii/s0304389405006370 https://www.sciencedirect.com/science/article/abs/pii/s0304389405006370 https://www.sciencedirect.com/science/article/abs/pii/s0304389405006370 https://www.sciencedirect.com/science/article/abs/pii/s0304389405006370 https://scielo.conicyt.cl/scielo.php?pid=s0717-34582004000300014&script=sci_arttext&tlng=en https://scielo.conicyt.cl/scielo.php?pid=s0717-34582004000300014&script=sci_arttext&tlng=en https://scielo.conicyt.cl/scielo.php?pid=s0717-34582004000300014&script=sci_arttext&tlng=en https://scielo.conicyt.cl/scielo.php?pid=s0717-34582004000300014&script=sci_arttext&tlng=en https://scielo.conicyt.cl/scielo.php?pid=s0717-34582004000300014&script=sci_arttext&tlng=en https://journals.tubitak.gov.tr/engineering/abstract.htm?id=9035 https://journals.tubitak.gov.tr/engineering/abstract.htm?id=9035 https://journals.tubitak.gov.tr/engineering/abstract.htm?id=9035 https://journals.tubitak.gov.tr/engineering/abstract.htm?id=9035 https://journals.tubitak.gov.tr/engineering/abstract.htm?id=9035 https://journals.tubitak.gov.tr/engineering/abstract.htm?id=9035 https://www.researchgate.net/profile/senthil_kumar_ponnusamy/publication/49593964_adsorption_of_pb2_ions_from_aqueous_solutions_onto_bael_tree_leaf_powder_isotherms_kinetics_and_thermodynamics_study/links/5576ab7e08aeacff1ffe6fc9.pdf https://www.researchgate.net/profile/senthil_kumar_ponnusamy/publication/49593964_adsorption_of_pb2_ions_from_aqueous_solutions_onto_bael_tree_leaf_powder_isotherms_kinetics_and_thermodynamics_study/links/5576ab7e08aeacff1ffe6fc9.pdf https://www.researchgate.net/profile/senthil_kumar_ponnusamy/publication/49593964_adsorption_of_pb2_ions_from_aqueous_solutions_onto_bael_tree_leaf_powder_isotherms_kinetics_and_thermodynamics_study/links/5576ab7e08aeacff1ffe6fc9.pdf https://www.researchgate.net/profile/senthil_kumar_ponnusamy/publication/49593964_adsorption_of_pb2_ions_from_aqueous_solutions_onto_bael_tree_leaf_powder_isotherms_kinetics_and_thermodynamics_study/links/5576ab7e08aeacff1ffe6fc9.pdf https://www.researchgate.net/profile/senthil_kumar_ponnusamy/publication/49593964_adsorption_of_pb2_ions_from_aqueous_solutions_onto_bael_tree_leaf_powder_isotherms_kinetics_and_thermodynamics_study/links/5576ab7e08aeacff1ffe6fc9.pdf http://lejpt.academicdirect.org/a22/083_092.pdf http://lejpt.academicdirect.org/a22/083_092.pdf http://lejpt.academicdirect.org/a22/083_092.pdf http://lejpt.academicdirect.org/a22/083_092.pdf http://lejpt.academicdirect.org/a22/083_092.pdf t. h. mhawesh and z. t. abd ali / iraqi journal of chemical and petroleum engineering 21,2 (2020) 15 23 23 يونات النيكل من المحاليل المائيةاإعادة استخدام نفايات الطابوق كمادة رخيصة إلزالة طيبه مهاوش و زياد عبد علي جامعة بغداد, كلية الهندسة, قسم الهندسة البيئية الخالصة ni +2( كمواد منخفضة التكلفة إلزالة أيونات gbwتمت دراسة امكانية تطبيق حبيبات مخلفات الطوب ) من خالل العديد من الفحوصات مثل حيود األشعة السينية gbwمن المحاليل المائية. تم تحديد خصائص (xrd( األشعة السينية المشتتة للطاقة ، )edx( المجهر اإللكتروني المسح الضوئي ، )sem والمساحة ، ) بما في ذلك وقت االتصال السطحية. في اختبارات الُدفعات ، تم فحص تأثير العديد من العوامل . كانت أفضل قيم المعامالت التي وفرت أقصى كفاءة إزالة gbwوالتركيزاالبتدائي وسرعة الرج وجرعة ، على التوالي. بيانات g/100ml 1.8، و 1.5hr ،50mg/l ،250rpm%( : 39.4للرصاص ) الثالثة isothermضعت لنماذج االمتصاص التي تم الحصول عليها من خالل تجارب الُدفعات التي خ وصف بشكل freundlich. أظهرت النتائج أن نموذج elovich)،و langmuir ،freundlichالمسماة ) ( بالمقارنة مع النماذج األخرى. وقد تم تحليل البيانات الحركية r2 0.9176جيد بيانات االمتصاص )= -pseudo(. تم ايجاد ان pseudo-second-orderو pseudo-first-orderباستخدام نموذجين : first-order .يمثل جيدا البيانات التجريبية مياه الصرف الصحي ,نفايات القرميد , ni + 2الكلمات الدالة: االمتصاص, iraqi journal of chemical and petroleum engineering vol.18 no.4 (december 2017) 15 23 issn: 1997-4884 study and analysis of concentric shell and double tube heat exchanger using tio2 nanofluid bassma abbas abdulmajeed and noor sabih majeed college of engineeringuniversity of baghdad abstract in this paper, nanofluid of tio2/water of concentrations of 0.002% and 0.004% volume was used. this nanofluid was flowing through heat exchanger of shell and concentric double tubes with counter current flow to the hot oil. the thermal conductivity of nanofluid is enhanced with increasing concentrations of the tio2, this increment was by 19% and 16.5% for 0.004% and 0.002% volume respectively relative to the base fluid (water). also the heat transfer coefficient of the nanofluid is increased as reynold's number and nanofluid concentrations increased too. the heat transfer coefficient is increased by 66% and 49% for 0.004% and 0.002% volume respectively relative to the base fluid. this study showed that the friction factor of nanofluid was decreased as reynold's number increased. key words: nanofluid, tio2/water, shell and double tube heat exchanger, enhanced thermal conductivity, enhanced heat transfer coefficient. introduction nowadays, the world is experiencing many confronts in with heat transfer problems in different engineering processes. to increase heat transfer, many investigators found that nanofluid is one of the suitable coolant which increase the efficiency of various engineering instruments. the nanofluids are the perfect fluids for rapid heating and cooling. [1, 2] choi and eastman in 1990 are the first who started to study nanofluids. later many researchers continued their studies comprising different nanoparticles such as al2o3, tio2 and cuo. [3, 4] pak and cho, 1998 studied the effect of al2o3/water and tio2/water nanofluids of concentration 3%volume flowing into horizontal tube, they found that the nusselt number was increased with increasing volume concentration of nanofluid and reynold's number was increased too [5]. ding et al, 2007 investigated the tio2/eg nanofluid in forced convection. the heat transfer coefficient was enhanced relative to base fluid, because of the thermal conduction enhancing [6]. duangthongsuk and wongwises, 2009 studied the effect of tio2/water nanofluid in a heat exchanger of concentration of 0.2%. the higher temperature affected the nanofluid working in heat exchanger. university of baghdad college of engineering iraqi journal of chemical and petroleum engineering study and analysis of concentric shell and double tube heat exchanger using tio2 nanofluid 16 ijcpe vol.18 no.4 (dec. 2017) -available online at: www.iasj.net they found that the heat transfer coefficient was increased when the temperature of the nanofluid was low [7]. yannar et al, 2011 studied different types of nanofluids (al2o3/water, tio2/water and cuo /water) of different concentration 1%, 1% and 3% respectively, of spiral pipe heat exchanger. the heat transfer coefficient increased by 28% of 0.8% concentration [8]. kavitha et al, 2012 studied the effect of tio2/water nanofluid used in the transient hot wire device. the thermal conductivity of nanofluid was increased by using spherical shape nanoparticles. the thermal conductivity depended on some factors such as: size, shape and stability of nanofluids [9]. arani and amani, 2012 studied the effect of tio2/water nanofluid of concentration range from 0.002 to 0.02 by volume and the particle size of 30nm in a double pipe heat exchanger of counter current arrangement. they found that the nusselt number increased as reynold's number increased [10]. abdul hamid et al, 2015 studied the effect of tio2/water eg (ethylene glycol) in volume ratio 60: 40 nanofluid of three concentrations of 0.5%, 1% and 1.5% on the pressure drop in a horizontal tube, they found that the pressure drop was increased with the increasing volume concentration and decrease with increasing the temperature of nanofluid [11]. they studied the effect of tio2/water of particle size 50nm of three concentrations 0.5%, 1% and 1.5% on heat transfer coefficient. the maximum enhancement was by 22.75% and 28.92% at temperature of 50c and 70c at concentration of 1.5% concentration [12]. in this study, investigating the tio2/ water nanofluid of two volume concentrations of 0.002, 0.004% of 50 nm particle size in shell and double concentric tubes heat exchanger in turbulent flow region was accomplished. experimental setup the shell and double concentric tubes heat exchanger constructed by [13] was used in this work. three streams of fluids were designed to work in the shell and double concentric tube heat exchanger, two flows as hot fluids and one cold nanofluids in the opposite direction. the heat exchanger had a (1.3m) length and with effective tube length of (1.08m). the shell inner diameter is (203mm), and the shell outer diameter is (220mm). baffles of thickness (6mm) were spaced by distance of (100mm). the inner tubes were made of carbon steel, with (20mm) inside diameter and (25mm) outside diameter. they were divided as triangular (30) tube pattern. the clearance between two adjacent tubes is (6.25mm), and the tubes pitch is (31.25mm). a second group of 16 carbon steel tubes of (6mm) inside diameter and (10mm) outside diameter, as concentric inner tubes, were used to offer two passes tube side. preparation of nanofluid nanofluids were prepared by two step method of preparation. the nanopowders are dispersed in the water (base fluid) at specific concentrations (0.002 and 0.004) % by volume. the nanopowders were weighed by using electronic balance in the hood of laboratory to avoid the pollution with nanoparticles. a 250 litter of nanofluids were prepared each time using a speed homogenizer (ultra – turax janke &kunkel kg) to keep the nanoparticles in motion. bassma abbas abdulmajeed and noor sabih majeed -available online at: www.iasj.net ijcpe vol.18 no.4 (dec. 2017) 17 this motion stabilizes the suspension and prevents the agglomeration and sedimentation. the shear mixing device is of 10000 rpm. the mixing continued for 2 hours. the shear agitation continued for 48 hours. the densities of nanofluid and oil were measured by pcknometer of 10 ml, while the viscosities were measured by viscometer astm d445 viscometer bath. the thermal conductivities for nanofluid and oil was measured by kd2 pro thermal property analyzer (decagon device, pullman, wa, usa). the temperature at which the thermal conductivity of nanofluid was measured was 25c, while for oil ranged as (85, 75, 65, 55 c). procedure the cold feed or nanofluid tank is of capacity of 300 litter and was supported by a mixer on the top to prevent coagulations and sedimentation of nanoparticles. the mixer has three paddles of width (20cm) and (3mm) thickness, with a speed of (100 rpm). a centrifugal pump (type, sp24t) was used to pump the nanofluids. the nanofluid enters the heat exchanger at the annulus side between the shell and inner tubes, and exits from the exchanger to the collector tank. the nanofluid returns back to the main tank, where it was left for a certain period of time for cooling it to the desired temperature and it's was measured using a portable thermocouple (type k). the hot feed (oil) was entered in a tank with square front face provided by two heaters to reheat the oil at the desired temperature with a thermostat connected to the controlling board to control the temperature. the oil has been pumped by centrifugal pump with provided by gate valve on the pipes before enter to the flow meter. the feed is divided into two parts supported by pressure gauge at the inlet and outlet of the exchanger. a second tank was used to collect the oil, which gets out from the heat exchanger. the two oil streams were provided with two thermocouples type (k) to record the temperature for both shell and inner tubes of heat exchanger. on the cold feed side, the nanofluid is pumped and the oil centrifugal pump is started at the same time at the desired flow rates of both fluids. when the flow of both fluids were in a steady state, the cold side nanofluid flow was at rate of (45) l/min and a temperature of 20 c, while the hot oil was pumped at varied flow rates (30, 40, 50) l/min, and at in temperatures between 85 c to 55 c. the pressures are recorded at the inlet and outlet of the heat exchanger for both pipe and shell sides, annulus tube and inner tubes. the procedure is repeated for flow rate of cold nanofluid in the annulus side as (15, 25, 35) l/min with fixed temperature of 20 c. this step was repeated after changing the setting of thermostat by 10 c step for temperature of hot oil from 55 to 85c. fig.(1) shows the whole equipment's process. fig. 1, rig of experimental process study and analysis of concentric shell and double tube heat exchanger using tio2 nanofluid 18 ijcpe vol.18 no.4 (dec. 2017) -available online at: www.iasj.net the mass flow rate in the annulus of the concentric tube is a function of the density of the fluid, the velocity of the fluid, flow cross sectional area and the number of tubes, as in [13]. p tc n nau m 2 22 2   … (1) where the inner flow cross sectional area of the annulus passages is:  2 1 2 22 4 dda c   … (2) and (np) is the number of tubes per pass in the heat exchanger, u2 the velocity of fluid in annulus, reynolds number is calculated as follows: 2 22 2 re   h du  … (3) the hydraulic diameter of the annulus is: 12 ddd h  … (4) to calculate the prandtl number: 2 22 2 pr k cp  … (5) by using colburn equation, the nusselt number, [14]: 33.08.0 prre023.0 k hd h … (6) the pressure loss inside tubes of circular cross section or annulus passage in a shell and double concentric tube heat exchangers is the sum of the friction loss within the tubes and the turn losses between the passes of the exchanger. 2 44 2 22 22 u n d ln fp p h p           … (7) and the friction factor in annulus passages: 25.0 2 re316.0  f … (8) for 2300 <re <105 overall heat transfer coefficient u12 between (the fluid in the shell side and fluid in the annulus passage), [15]. 22 12 11 2 12 1 ln 2 1 hd d k d hd d u w   … (9) the second overall heat transfer coefficient u23 between (the fluid in the annulus passage and the fluid in the inner tube side), [15]. 32 12 21 2 23 1 ln 2 1 hd d k d hd d u w   … (10) results and discussion thermal conductivity of nanofluid the thermal conductivity of nanofluid increased due to the thermal properties of nanoparticles which has higher thermal conductivity than water [16]. for 0.002% volume of tio2, the thermal conductivity was increased by 16.5% from the base fluid at temperature of 25c and that is due to the stable nanofluids preparation as in [17]. bassma abbas abdulmajeed and noor sabih majeed -available online at: www.iasj.net ijcpe vol.18 no.4 (dec. 2017) 19 by doubling the concentration of the titanium oxide, the thermal conductivity was increased by increasing the concentration of nanoparticles by 19% from the base fluid (water). this is in agreement with [18]. table (1) shows the values of thermal conductivities of base fluid and nanofluid with titanium oxide nanoparticles. table 1, thermal conductivity of tio2/water fluids tio2 concentration% thermal conductivity k (w/m.k) base fluid (water) 0 0.612 tio2/water 0.002 0.713 0.004 0.724 the effect of nanofluid on heat transfer coefficient the heat transfer coefficient of nanofluid increased as reynold's number increased, and this is due to enhancing of thermal conductivity of tio2 nanofluid. also the brownian motion of the nanoparticles in the base fluid promoted which led to the good distribution of these particles in the base fluid. figs. (2) and (3) showed that the heat transfer coefficient of two concentrations 0.002 % and 0.004% volume of tio2 increased as reynold's number of nanofluids increased. fig. 2, heat transfer coefficient of nanofluid of tio2 of concentration 0.002 % against reynold's number at different nanofluid flow rates of (15, 25, 35, 45) l/min with different temperatures of oil. the maximum value of heat transfer coefficient was at temperature of 85 c for oil. this is because of the large difference between the inlet temperatures of the two streams entering the heat exchanger. this agreed with ehsan, 2016 [19]. the heat transfer coefficient of nanofluid increased as volume concentration of tio2 was increased. this agreed with reza a., 2014 [20] of diffident flow rates of nanofluids (15, 25, 35, 45) l/min and different temperatures and flow rates of oil. fig. 3, heat transfer coefficient of nanofluid of tio2 of concentration 0.004 % against reynold's number at different nanofluid flow rates of (15, 25, 35, 45) l/min with different temperatures of oil study and analysis of concentric shell and double tube heat exchanger using tio2 nanofluid 20 ijcpe vol.18 no.4 (dec. 2017) -available online at: www.iasj.net fig. (4) showed a comparison between three types of fluids, 0.002 % tio2, 0.004% tio2 and base fluid water. the figure shows that tio2 nanofluid of concentration 0.004% volume has high values of heat transfer coefficient with respect other fluids. this enhancement represented by 66% and 49% increase for 0.002 % tio2 and 0.004% tio2 respectively than the base fluid. fig.4, heat transfer coefficient of different fluids reynold's number at different nanofluid flow rates of (15, 25, 35, 45) l/min with temperatures of 85c of oil the effect of nanofluid on friction factor the friction factor decreased as reynold's number increased as shown in figs. (5) and (6). this is due to the increasing in the flow velocity of nanofluids [21]. the friction factor was increased with increasing in concentration of nanoparticles. this is due to viscosity of nanofluids which increased with increasing of the nanofluids concentration that causes slow motion nanofluids namly increasing friction factor [22]. figs. (5) and (6) shows that the friction factor was increased when the temperature of oil was decreased, at maximum flow rate of tio2 nanofluid of 45 l/min. fig. 5, friction factor against the reynold's number at 0.002% volume of tio2 nanofluid of flow rate 45 (l/min) and different oil temperatures at constant flow rate of 50 (l/min) fig.6, friction factor against the reynold's number at 0.004% volume of tio2 nanofluid of flow rate 45 (l/min) and different oil temperatures at constant flow rate of 50 (l/min) in fig. (7) the comparison between fluids showed that the base fluid water has higher friction factor followed by 0.002% of tio2 nanofluid and that was because of the lower reynold's number of fluid compared to 0.004% tio2 nanofluid. bassma abbas abdulmajeed and noor sabih majeed -available online at: www.iasj.net ijcpe vol.18 no.4 (dec. 2017) 21 fig. 7, friction factor against flow rate of nanofluids at constant oil flow rate 50 (l/min) and temperature of 85c of different fluids and concentration. conclusion 1the thermal conductivity of nanofluids increased with increasing in volume concentrations of tio2 nanoparticles at temperature of 20c. the enhancement in thermal conductivities of 0.004% and 0.002% volume concentration for tio2/water nanofluids by 19% and 16.5% respectively over base fluid. 2the heat transfer coefficient was increased as reynold's number and volume concentration increased too. this enhancement of heat transfer coefficient for 0.004% and 0.002% of tio2/water nanofluids by 66% and 49% respectively from the base fluid. 3friction factor of nanofluids decreased as reynold ' s number was increased. the friction factor of nanofluids are lower than the base fluid because the flow of the base fluid is in the laminar flow region, so that the high volume of friction factor was appeared. nomenclature symbol description units ac cross sectional area of the tube in conventional heat exchanger m 2 cp specific heat j/kg.k d diameter of the tube (first bundle) in new heat exchanger m d diameter of the inner tube (second bundle) in new heat exchanger m dh hydraulic diameter of the annulus in the new heat exchanger m f friction factor h heat transfer coefficient w/ m 2 .k k thermal conductivity w/m.˚c l length of the heat exchanger m m mass flow rate kg/min nu nusselt number k hd nu  np number of tubes per pass nt total number of the tubes pr prandtle number k cp pr re reynolds number  ud re t temperature ˚c u overall heat transfer coefficient w/m 2 ˚c u fluid velocity m/s study and analysis of concentric shell and double tube heat exchanger using tio2 nanofluid 22 ijcpe vol.18 no.4 (dec. 2017) -available online at: www.iasj.net greek symbols units description symbol δt temperature difference ˚c ρ density kg/m 3 μ dynamic viscosity kg/m.s δp pressure drop pa subscript symbols description 1 oil (shell side) 2 tio2/water (annulus side) 3 oil (inner tube side) 12 shell and annulus 23 annulus and inner tube  base fluid n nanofluid t tube side p nanoparticle references 1rao g.s., sharma k.v., chary s.p., bakar r.a., m.m. rahman m.m., kadirgama k. and noor m.m., 2011," experimental study on heat transfer coefficient and friction factor of al2o3 nanofluid in a packed bed column", journal of mechanical engineering and sciences, vol. 1, pp. (11-15). 2mahendran m., lee g.c., sharma k.v., shahrani a., 2012," performance of evacuated tube solar collector using water-based titanium oxide nanofluid", journal of mechanical engineering and sciences, vol.3, pp. (301-310). 3choi u.s., 1995,"enhancing thermal conductivity of fluids with nanoparticles'', in: d.a. siginer, h.p.wang (eds.) developments and applications of nonnewtonian flows, american society of mechanical engineers (asme), new york. pp. (99–105). 4eastman j.a., choi s.u.s., li s., thompson l.j., lee s., 1997," enhanced thermal conductivity through the development of nanofluids", in: proc. symposium nanophase and nanocomposite materials ii, materials research society, boston, ma. pp. (3–11). 5pak bc., cho yi., 1998, "hydrodynamic and heat transfer study of dispersed fluids with submicron metallic oxide particles", journal of experimental heat transfer, vol.11, issue 2, pp. 151-170. 6ding y, chen h, he y, lapkin a, yeganeh m, šiller l, 2007," forced convective heat transfer of nanofluids", advanced powder technology, 18:813-24. 7duangthongsuk w, wongwises s., 2009," heat transfer enhancement and pressure drop characteristics of tio2/water nanofluid in a doubletube counter flow heat exchanger", international journal of heat and mass transfer, 52:2059-67. 8yanuar, putra n., gunawan s.m.bagi, 2011," flow and convective heat transfer characteristic of spiral pipe for nano fluid", international journal of research and reviews in applied sciences, ijrras 7(3). 9kavithat., rajendren a., durairajen.a, syedabuthahir s., 2012. "advanced heat transfer enhancement using titanium oxidewater based nano fluid", international journal of management in education, ijmie, vol. 2, issue 4. 10arani a.a.a. and amani j., 2012," experimental study on the effect of tio2–water nanofluid on heat transfer and pressure drop", experimental thermal and fluid science. vol. 42, pp. (107-115). bassma abbas abdulmajeed and noor sabih majeed -available online at: www.iasj.net ijcpe vol.18 no.4 (dec. 2017) 23 11abdul hamid1 k., azmi1 w.h., rizalman m., usri1 n.a., najafi g., 2015," effect of titanium oxide nanofluid concentration on pressure drop", arpn journal of engineering and applied sciences, vol. 10, no. 17, pp. 78157820. 12abdul hamid k., azmi1 w.h., rizalman m., usri1 n.a., najafi g., 2015, "effect of temperature on heat transfer coefficient of titanium dioxide in ethylene glycol-based nanofluid", journal of mechanical engineering and sciences (jmes) vol.8, pp. 1367 1375. 13fadhil a.a., 2013, “shell and double concentric tubes heat exchanger calculations and analysis”, a thesis for master of science in chemical engineering, university of baghdad. 14hewitt, g.f., spires, g. l., and bott, t. r., 1994, process heat transfer, crc press. 15bougriou, c., baadache, k., 2008, "shell-and-double concentric tube heat exchangers", patent pct, dz2008/000002. 16seok p. j. and stephen u. s. ch., 2004, "roles of brownian motion in the enhanced thermal conductivity of nanofluids", applied physics letters, vol. 24, no. 21. 17ravi p., paul m., jacob f., patrick ph., pawel k., 2006,"effect of aggregation on thermal conduction in colloidal nanofluids", applied physics letters, vol. 89. 18raghu g., hongwei s., pengtao w., majid ch. fan g., zhiyong g. and bridgette b., 2010,"effects of particle surface charge, species, concentration, and dispersion method on the thermal conductivity of nanofluids", advances in mechanical engineering, id 807610, 10 pages. 19ehsan e. b., mohammad c. m., hamid n.w., weerapun d., somchai w., 2016," experimental and numerical investigation of nanofluids heat transfer characteristics for application in solar heat exchangers", international journal of heat and mass transfer, vol. 92, pp. (1041– 1052) 20reza a., heydar m., malihe z., mehdi d., and sahar g., 2014," heat transfer of nanofluid in a double pipe heat exchanger", international scholarly research notices, article id 736424, 7 pages. 21vatsal. s. p., ragesh. g. k., dipak a. d., 2013,"an experimental study of counter flow concentric tube heat exchanger using cuo / water nanofluid", international journal of engineering research & technology, vol. 2 issue 6, pp. (914920). 22adnan m. h., sharma k. v., bakar r. a., and kadirgama k., 2013,"the effect of nanofluid volume concentration on heat transfer and friction factor inside a horizontal tube", article id 859563, 12 pages. available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.23 no.4 (december 2022) 59 – 69 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: nizar a. jawad, email: nizar.jawad1607m@coeng.uobaghdad.edu.iq, name: tariq m. naife, email: tariq.mohammed@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. mathematical modeling and kinetics of removing metal ions from industrial wastewater nizar a. jawad and tariq m. naife chemical engineering department – college of engineering – university of baghdad abstract the study's objective is to produce nano graphene oxide (go) before using it for batch adsorption to remove heavy metals (cadmium cd+2, nickel ni+2, and vanadium v+5) ions from industrial wastewater. the temperature effect (20-50) °c and initial concentration effect (100-800) mg l-1 on the adsorption process were studied. a simulation aqueous solution of the ions was used to identify the adsorption isotherms, and after the experimental data was collected, the sorption process was studied kinetically and thermodynamically. the langmuir, freundlich, and temkin isotherm models were used to fit the data. the results showed that cd, ni, and v ions on the go adsorbing surface matched the langmuir model with correlation coefficients (r2) of 0.999. kinetic models studied showed that a pseudo-second-order model was followed and thermodynamically, the process was exothermic due to ∆h negative, the reduction in randomness because of negative ∆s. additionally, spontaneous adsorption of metal ions was ∆g negative values influenced. keywords: nano graphene oxide; heavy metal; wastewater; langmuir model; pseudo-second-order; thermodynamic study. received on 30/06/2022, accepted on 25/08/2022, published on 30/12/2022 https://doi.org/10.31699/ijcpe.2022.4.8 1introduction with the expansion of industry and human activity, there are more heavy metals in industrial wastewater. mining, plating and electroplating, batteries, insecticides, metal rinse operations, rayon, tanning, bioreactors of fluidized bed, the industry of textile, metal smelting, applications of electrolysis, a paper production, as well as petrochemicals, are some examples. the wastewater from oil refineries is the most significant of these [1,2]. heavy metal-contaminated water enters the ecosystem, harming both human health and the environment. because heavy metals do not biodegrade [3] and may cause cancer, as well as their inappropriate concentration in water, which may have serious negative effects on the health of living things [4,5]. industrial wastewater effluent may include a set of heavy metals, like zinc (zn), mercury (hg), iron (fe), lead (pb), arsenic (as), silver (ag), chromium (cr), boron (b), manganese (mn), calcium (ca), molybdenum (mo), cobalt (co), antimony (sb), and others may be found in industrial effluent. the most prevalent heavy metals in effluent from oil refineries are cadmium (cd), nickel (ni), and vanadium (v). based on the table 1 highlights ni, cd, and v ions, emphasizing their main sources, health consequences, and the allowable level in drinking water. conventional approaches for removing heavy metal pollution from wastewater include precipitation via coagulation and flocculation [7], electrochemical purification [8], membrane separation [9], and adsorption [10,11]. adsorption is the most promising of these technologies because of its low cost, high efficiency, versatile design, and ease of operation. nanomaterials are the adsorbent in the majority of typical adsorption systems because of their unique properties like a specific surface area is high, a large number of binding sites for the adsorbates to be adsorbed, numerous functional groups, and appropriate pore size, this makes them appealing adsorbents for the treating industrial wastewater polluted with heavy metals [12,13]. the go has exceptional adsorption qualities, particularly in liquid-solid systems, according to several studies. its structure demonstrates the presence of oxygen groups in the aromatic ring, such as carbonyl, carboxyl, and hydroxyl groups, which makes it highly hydrophilic and gives the go a high capacity for adsorption of metal ions pollutants because of its high surface area and ability to disperse in water [14]. go is often manufactured by oxidative exfoliation of natural graphite using the well-known hummers technique [15,16]. in this research, go was prepared using methods reported in the literature [17] and also studied the influence of initial concentration and temperature on the removal of heavy metal ions from wastewater by batch adsorption process. as well as various models were used to assess the adsorption isotherm, kinetics, and thermodynamics at the solid-liquid interface. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:nizar.jawad1607m@coeng.uobaghdad.edu.iq mailto:tariq.mohammed@coeng.uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2022.4.8 n. a. jawad and t. m. naife / iraqi journal of chemical and petroleum engineering 23,4 (2022) 59 69 60 table 1. typical of the key heavy metals occurring in industrial wastewater and their origins, as well as the health risks caused by inadequate levels and the authorized amounts in drinking water according to the guidelines of the (who) [5] heavy metal ions major sources the most impacted organ and system permitted quantities (μg) cadmium (cd) metal refineries, batteries, paints, the steel and plastic industries, and rusted galvanized pipes. the bones, liver, kidneys, lungs, testes, brain, immune system, and cardiovascular system are all affected. 3 nickel (ni) stainless steel and nickel alloy production. lung, kidney, gastrointestinal distress, pulmonary fibrosis, and skin. 70 vanadium (v) flue dust from smokestacks of ship boiler, crude oil toxic element, green tongue, cramps, diarrhea, and neurological 100 2experimental 2.1. materials powder of natural graphite, 99% purity, glentham life sciences l.td co. hydrochloric acid hcl (35-38% concentration, bhd laboratory, germany). sulphuric acid h2so4 (98% concentration, sigma-aldrich, india). hydrogen peroxide h2o2 (30% concentration, pubchem, germany). potassium permanganate powder kmno4 (fisher scientific, india), sodium hydroxide naoh (98% concentration, sdfcl, india), and deionized water (di water). 2.2. synthesis of nano graphene oxid go go was prepared by modifying the hummers technique [18]. graphite powder (1.0 g) and concentrated h2so4 (24 ml) were poured into an ice bath and agitated at 200 rpm by using a hotplate magnetic stirrer (labtech lms1003/korea), followed by the gradual addition of kmno4 (3.0 g) to keep a temperature below 10°c. the reaction system was then placed in a 40°c paraffin-oil bath and aggressively stirred (300 rpm) for about 30 min. after adding 50 ml of di water to the solution, it was stirred for 15 min at 95°c. dropwise addition of 5 ml h2o2 followed by 150 ml di water. the solution's transformation from dark brown to yellow-brown indicates that the graphite has oxidized. the suspension was filtered and washed with (150 ml) of a 1:9 hcl aqueous solution with metal ions removed. the remaining acidic or metallic substances were then rinsed away with 1 l of water. the resulting go dispersion was poured into 300 ml of water and ultrasonicated at 40 khz frequency for 0.5 hr. the go dispersion was then centrifuged for one hour at 5000 rpm to eliminate any un-exfoliated particles. the resultant substance was then dried at 60°c for 24 hr to produce go. 2.3. characterization the x-ray diffraction xrd analysis was the most important test which is performed to establish the existence of go and to learn about its crystalline properties, where the effective production of the go at the peak 2θ range of 10-12 degrees [18] the go exhibited a very significant peak at 2θ = 10.92° as shown in fig. 1 a. fourier-transform infrared spectrometer to analyze the morphology of go (ftir; thermo scientific inc., nicolet is10, boston, ma, usa) shows peaks corresponding to oxygen-containing functional groups, the prominent peak between 3403.27 and 2925.2 cm-1 is due to hydroxyl o-h stretching, and the absorption peak at 2344.97 cm-1 is due to the c=o bond. that result shows that go was produced [19], as shown in fig. 1 b. scanning electron micrographs sem (gemini sem 500, zeiss, germany) were used to perform thorough morphological examinations, where the graphite oxidation rate is indicated by its crystallization. the photo shows that go is composed of randomly aggregated and thin folded sheets with surface creases and folds [20], as shown in fig. 1 c. fig. 1. a. xrd, b. ftir, c. sem for go 10 20 30 40 50 0 100 200 300 400 500 600 in te n s it y ( a .u .) 2 ө a. xrd b.ftir pr dc go thu j an 20 14:56:57 2022 ( gmt-08:00) n umber of s ample s c ans : 10 n umber of bac k gr ound s c ans : 10 r es olution: 4.000 sample gain: 1.0 optic al v eloc ity : 0.6329 aperture: 100.00 8 2 9 .0 4 1 0 4 5 .6 0 1 3 8 0 .6 6 1 6 1 3 .5 7 1 7 1 5 .7 22 3 4 4 .9 7 2 8 4 3 .4 8 2 9 2 5 .2 0 3 4 0 7 .2 3 1 2 3 4 5 6 7 8 9 10 11 12 13 14 % t 500 1000 1500 2000 2500 3000 3500 wav enumbers (c m-1) c. sem n. a. jawad and t. m. naife / iraqi journal of chemical and petroleum engineering 23,4 (2022) 59 69 61 2.4. adsorption capacity of heavy metal ions in batch on go utilizing simulated solutions created by diluting the stock solution to the required concentration in a water bath shaker with deionized water, adsorption tests were performed. to avoid spillage during the shaking operation, 100 ml of an aqueous solution containing heavy metals (cd+2, ni+2, and v+5) were placed in 150 ml glass flasks and tightly covered in aluminum foil. the hcl (0.1 m), and naoh (0.1 m) solutions were utilized to control the solution's acidic properties. furthermore, the specified amounts of adsorbent go were added to the heavy metals aqueous solution. the treatment technique begins by altering the temperature (20-50) °c and the starting concentration within the range of (100-800) mg l1, maintained under optimal operating conditions (ph= 7.5, time t= 150 min, rpm= 375, 100 mg of go) [21,22]. when the timer runs out, the shaker (thermo scientific maxq shke7000 benchtop, model 4303\ germany) is switched off, the flasks are removed, and the samples are filtered using filter paper. the atomic absorption spectrophotometer aas (aas sensaa gbc \ uk) is used to measure the concentration of residual heavy metals and the percentage of removal (%r), as well as the capacity of the adsorbent for batch adsorption (𝑞𝑒 ), after the adsorbent material has been separated from the solution, using equations (1) and (2), respectively. %𝑅 = 𝐶𝑖−𝐶𝑓 𝐶𝑖 × 100 (1) 𝑞𝑒 = 𝑉 𝑚 × (𝐶𝑖 − 𝐶𝑓) (2) where r: denotes the percentage of heavy metal ions removed, 𝑞𝑒 : denotes the adsorption capacity of adsorbent media (𝑚𝑔.𝑔-1), 𝐶𝑖 and 𝐶𝑓: denote the initial and the end concentrations of heavy metal ions, respectively (𝑚𝑔 l-1), 𝑚: denotes the mass of adsorbent used for adsorption (𝑔), and v: denotes the volume of solution (l). 2.5. study isotherm, kinetic, and thermodynamic of the adsorption process as an adsorbent, 100 mg of go was added to 100 ml. of aqueous solutions containing cd, ni, and v at a set starting concentration of (100-800) mg l-1 and temperature (20-50) °c to perform the experiments for the adsorption kinetics investigation. the samples were gathered, and the aas technique was used to calculate the concentrations of cd, ni, and v in the aqueous solutions; under ideal circumstances. equation (3) was used to calculate the heavy metal ion's adsorption capacity at time t (qt) expressed in mg g -1 [19]. 𝑞𝑡 = 𝑉 𝑚 × (𝐶𝑖 − 𝐶𝑒 ) (3) where: ci (mg l −1) is the initial concentration of each ion and ce (mg l −1) is the equilibrium adsorbed concentration, v is the volume (l) of the solution of the respective ion and m is the mass of adsorbent (g). 3result and discussion 3.1. adsorption performance a. temperature effect (t) the impact of removing temperature on the efficiency for cd, ni, and v ions using go in a batch mode adsorption unit is shown in fig. 2 under optimal conditions. at the changing temperature (20-50) °c, the maximum removal is achieved at the lowest temperature, suggesting an inverse relationship between temperature and adsorption efficiency for all heavy metals tested and the adsorbent (go) applied. this proves that the adsorption was an exothermic process, which indicates that as the temperature rises, the bonds connecting the functional groups present in the active sites spread across the surface of go with cd, ni, and v ions break down, allowing the material to be released and returned to the solution, thereby decreasing the removal efficiency [19]. the highest removal of metal ions was seen at 20 °c where the adsorption capacity is decrease with an increase the temperature, after which adsorption reduced steadily with increasing temperature until it reached its lowest value. fig. 2. temperature effect on % removal of metal ions b. effect of initial concentration (ci) the influence of the starting concentration on the heavy metal adsorping process within the range of (100-800) mg.l-1 for cd, ni, and v under optimal circumstances for the remainder of the other design, as shown in fig. 3. the data collected demonstrate an inverse link between the two variables. for all heavy metal ions and adsorbent materials, the percentage removal falls as the initial concentration value rises [23]. there is no change in the surface area of the go, this indicates that there are a limited number of ions that may be adsorbable on the surface of the adsorbent. because the volume of the solution remains constant, increasing the contaminant concentration means increasing the ions of those metals, implying that heavy metal ions compete for the same amount of active sites on the adsorbent's surface [21]. as a consequence, fewer ions will be adsorbed and more heavy metal ions will be present in the contaminated n. a. jawad and t. m. naife / iraqi journal of chemical and petroleum engineering 23,4 (2022) 59 69 62 solution, decreasing the treatment's effectiveness. the highest adsorption capacity at ci 100 mg l -1 and the lowest at ci 800 mg l -1. fig. 3. initial concentration ci effect on % removal of metal ions 3.2. adsorption isotherm one may ascertain the connection between the concentration of the adsorbate and the amount of adsorption on the surface of the adsorbent at a constant temperature by measuring the adsorption isotherm of the ions from an aqueous solution on the go. to calculate go's ability to adsorb cd+2, ni+2, and v+5 ions from an aqueous solution. to establish the best model fit and calculate adsorption, the experimental isotherm data were examined using models. each model's parameters. the used models were langmuir, freundlich, and temkin. the models were used to replicate and comprehend the method by which cd, ni, and v ions adsorb on the graphene sheets constituting the nano graphene oxide (go) structure. these models are represented by the following equations, which also explain the significance of each parameter. a. langmuir model it is predicated on the idea that when the adsorbed solute forms a monolayer, the adsorbent has consistent adsorption energy at a constant temperature. expresses the linear form equation (4) [24]: 1 𝑞𝑒 = 1 𝑞𝑚𝑎𝑥𝐾𝐿 1 𝐶𝑒 + 1 𝑞𝑚𝑎𝑥 (4) where 𝑞𝑒: capacity of equilibrium adsorption (mg g-1), 𝐶𝑒: equilibrium adsorbed concentration (mg l-1), 𝐾𝐿: langmuir constant, expressed the binding sites (l mg-1) and 𝑞𝑚𝑎𝑥: the capacity of maximum adsorption (mg g-1). b. freundlich model according to this model, adsorption takes place on a heterogeneous surface with homogeneous energy across several layers, and equation (5) may be used to linearly characterize this process [23]: 𝑞𝑒 = 𝐾𝐹 𝐶𝑒 1 𝑛 (5) where: 𝑞𝑒 : the amount adsorbed per unit mass of adsorbent (mg g-1). 𝐾𝐹 : the freundlich constant represents the measured adsorption capacity [(mg g-1). (mg-1)1/n]. 𝑛: intensity of adsorption (-). c. temkin model the number of active sites on the adsorbent material's surface was proportional to the number of metal ions adsorbed. we can calculate the adsorption energy as well as the interactions between ions and go using temkin's model. according to temkin's model, adsorption is characterized as a uniform distribution of binding energy up to the maximum amount [23], which implies that the reduction in heat of absorption is linear rather than logarithmic as in freundlich's equation [24]. use equation (6) to apply the temkin isotherm: 𝑞𝑒 = 𝑅𝑇 𝑏 ln 𝐾𝑇 + 𝑅𝑇 𝑏 ln 𝐶𝑒 (6) where: 𝑞𝑒 : equilibrium capacity of adsorption (mg g -1), 𝑅: ideal gas constant (8.3144 j mol-1.°k-1), 𝐶𝑒: equilibrium adsorbed concentration (mg l-1), 𝑇: absolute temperature (°k), 𝐾𝑇: binding constant for temkin isotherm equilibrium (l mol-1), 𝑏: temkin isotherm constant related to the heat of adsorption (j mol-1). table 2 shows the constant amount of the langmuir, freundlich, and temkin isotherms, while fig. 4 to fig. 6 show these isotherms for go adsorption of the heavy metals cadmium, nickel, and vanadium, respectively. these findings demonstrate that the experimental results exhibit the following degree of model conformity: according to the magnitude of the correlation coefficient (r2), langmuir is superior to temkin and freundlich for the metals cd, ni, and v. the metal ions cd, ni, and v adsorption using go as adsorbents match the langmuir isotherm more closely than other models due to the correlation coefficient (r2) is high. depending on the value of the separation factor, the adsorption process is chosen. adsorption occurs on a monolayer surface with a particular number of identical patches, according to this theory. adsorption is a physical phenomenon that occurs on a heterogeneous surface. table 2. constant values of langmuir, freundlich and temkin isotherms for cadmium, nickel and vanadium ions adsorption using go metal langmuir freundlich temkin q max kl rl 2r kf n 2r bt kt 2r cd 653.595 0.01821 0.1207 0.99985 32.831224 1.88214 0.95213 137.888 0.1997 0.9914 ni 581.3953 0.03955 0.0595 0.99743 51.77876 2.13196 0.95712 127.963 0.3853 0.95712 v 621.1180 0.02546 0.0894 0.99943 40.4979 1.98428 0.95364 134.205 0.2644 0.992 n. a. jawad and t. m. naife / iraqi journal of chemical and petroleum engineering 23,4 (2022) 59 69 63 fig. 4. langmuir isotherm for (a. cadmium, b. nickel, and c.vanadium) adsorption by go fig. 5. freundlich isotherm for (a. cadmium, b. nickel, and c.vanadium) adsorption by go fig. 6. temkin isotherm for (a. cadmium, b. nickel, and c.vanadium) adsorption by go 3.3. adsorption kinetics it is a mathematical representation in the shape of a curve or a straight line that reflects the rate at which adsorbate ions were released from the medium of the aqueous or captured by the solid phase represented by the adsorbent surface under given operating conditions. as a consequence, a kinetic investigation is required to analyze the effectiveness and mechanics of the adsorption process. the pseudo-first-order model, pseudo-second-order model, elovich model, and intraparticle diffusion model are the most important kinetic models for modeling the adsorption process, and they were used to analyze the experimental results in this study [25,26]. a. pseudo first order model the lagergren model is named after swedish scientist sten yngve dennis lagergren, who suggested it in 1898. this model implies that adsorption occurs in a single layer between the liquid and solid phases at the adsorption surface. equation (7) demonstrates how to formally describe this model: 𝑑𝑞𝑡 𝑑𝑡 = 𝑘1(𝑞𝑒 − 𝑞𝑡 ) (7) where 𝑞𝑡 : is adsorbate adsorbed on to adsorbent at time 𝑡 (mg g-1), 𝑞𝑒 : is capacity of equilibrium adsorption (mg g-1), and 𝑘1: is rate constant (min-1 ). by integrating equation (7) at the boundary conditions of t = 0 to t = t and 𝑞𝑡 = 0 to 𝑞𝑡 = 𝑞𝑡 provided the linear form for this model, which is defined in equation (8) and may be shown by charting ln(𝑞𝑒 𝑞𝑡 ) versus t. the equilibrium constants 𝑘1 and ln 𝑞𝑒 are the slope and intercept, respectively. 𝑙𝑛 (𝑞𝑒 − 𝑞𝑡 ) = 𝑙𝑛 𝑞𝑒 − 𝑘1𝑡 (8) b. pseudo-second order model the dissolved ions' adsorption from an aqueous solution that results from interactions between physicochemical systems for the adsorbate (liquid phase) and the adsorbent is best modeled by the pseudo-second-order model (solid phase). in this model, it is a presumption that the number of active sites that are accessible on the surface of the adsorbent medium is related to the rate of adsorption. equation (9) is the formula for this model in mathematics. 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.002 0.004 0.006 0.008 0.010 0.012 1 /q e 1/ce y= 0.08402x + 0.00153 r 2 = 0.99989 a. cadmium 0.00 0.05 0.10 0.15 0.20 0.25 0.002 0.004 0.006 0.008 0.010 0.012 1 /q e 1/ce y= 0.04349x + 0.00172 r 2 = 0.99743 b. nickel 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0 6.2 6.4 ln q e ln ce y= 0.53131x + 3.49138 r 2 = 0.95213 c. vanadium 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0 6.2 6.4 ln q e ln ce y= 0.53131x + 3.49138 r 2 = 0.95213 a. cadmium 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0 6.2 6.4 ln q e ln ce y= 0.4691x + 3.947 r 2 = 0.9571 b. nickel 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0 6.2 6.4 ln q e ln ce y=0.504x + 3.7013 r 2 = 0.9536 c. vanadium 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 100 200 300 400 500 600 q e ln ce y= 137.888x 222.11 r 2 = 0.9914 a. cadmium 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 100 200 300 400 500 600 700 q e ln ce y= 127.963x 122.0598 r 2 = 0.95712 b. nickel 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 100 200 300 400 500 600 q e ln ce y= 134.205x 178.54 r 2 =0.992 c. vanadium n. a. jawad and t. m. naife / iraqi journal of chemical and petroleum engineering 23,4 (2022) 59 69 64 𝑑𝑞𝑡 𝑑𝑡 = 𝑘2(𝑞𝑒 − 𝑞𝑡 ) 2 (9) where 𝑞𝑒 : is the cyanide ion quantity adsorbate per unit mass of adsorbent at equilibrium (mg g-1), 𝑞𝑡 : is the cyanide ion quantity adsorbate per unit mass of adsorbent at any time (mg g-1), 𝑡 : is the time (min), and 𝑘2 : is the first second-order rate constant (g mg -1 min-1). equation (10), which may be depicted as a linear relationship by plotting 𝑡 /𝑞𝑡 vs t, was produced by integrating equation (9) at the boundary conditions from t= 0 to t= t and 𝑞𝑡 = 0 to 𝑞𝑡 = 𝑞𝑡 and rearranging the components. the slope and intercept are represented by 1/𝑞𝑒 and 1/𝑘2𝑞𝑒 2, respectively. 𝑡 𝑞𝑡 = 1 𝑘2𝑞𝑒 2 + 1 𝑞𝑒 𝑡 (10) c. elovich model in 1934, the belarusian physicist jakow borissowitsch zeldowitsch and the russian scientist s. z. roginsky developed this concept, which became known as the elovich model. this model claims that the adsorption rate decreases exponentially as the quantity of adsorbent adsorbed on the adsorption surface rises. consequently, equation (11) may be used to numerically represent this model: 𝑑𝑞𝑡 𝑑𝑡 = ⍺𝑒 −𝛽𝑞𝑡 (11) where ⍺: the rate of adsorption initial (mg g-1 min-1), and 𝛽 is the desorption constant. equation (12) produce by integrating equation (11) at the boundary conditions of t= 0 to t= t and qt= 0 to qt= qt and arranging the terms provided the linear form for this model: 𝑞𝑡 = 1 𝛽 𝑙𝑛 ( 1 ⍺𝛽 + 𝑡) + 1 𝛽 𝑙𝑛(⍺𝛽) (12) equation (12) can be written in the following equation (13) form, when the system is closer to an equilibrium state, 𝑡 ≫ (𝛼𝛽)-1: 𝑞𝑡 = 1 𝛽 ln 𝑡 + 1 𝛽 ln(⍺𝛽) (13) by plotting qt against 𝑡 we can represent a linear relationship, the (β)-1 and (β-1 ln ⍺β) are the slop and intercept respectively. d. intra-particle diffusion model this model was established by w.j. weber and j.c. morris in 1963, and it was used to compute the ratelimiting step. according to the model's assumptions, in four stages, the solute is transferred from the solution to the adsorption surface. if adsorbent material is present in the solution, the first step is the mass transfer (bulk movement), or the transfer of solute molecules. this procedure is quite rapid. the subsequent phase is film diffusion, in which the solute moves inside the border layer of the adsorbent material. the other step is surface diffusion, which involves the dispersion of solute particles and their migration towards the pores of the adsorption surface. the subsequent phase is pore diffusion, which consists of the adsorption of solute molecules to active sites on the adsorption surface. the formula (14) gives the mathematical equation that characterizes the intra-particle diffusion paradigm. 𝑞𝑡 = 𝑘𝑝 √𝑡 + 𝐶 (14) where 𝑘𝑝: rate constant (𝑚𝑔 𝑔 -1 𝑚𝑖𝑛-0.5), and 𝐶: boundary layer thickness. the values of 𝐶 determine the boundary layer effect—the higher values, the greater the effect. when plot 𝑞𝑡 against √𝑡 , the slope of the straight line indicates the constant time 𝑘𝑝 considering that the constant 𝐶 can be determined from the intercept, the equation is linear. table 3 includes the amount of the parameters of the four models of kinetic that were used to evaluate the study's results. fig. 7 to fig. 10 illustrate the practical data from the kinetic research on cd, ni, and v ions removal from aqueous solutions using go (i.e. pseudo first order, pseudo second order, elovich, and intra-particle diffusion models). the following kinetic model is most suited to reflect the data, according to the correlation coefficient values (r2) of the outcomes for each metal ion: for cd+2, pseudo second order model > pseudo first order model > elovich model > intra-particle diffusion. for ni+2, pseudo second order model > pseudo first order model > intra-particle diffusion > elovich model. and for v+5, intra-particle diffusion > pseudo first order model > pseudo second order model > elovich model. the cd+2 and ni+2 finding may be explained by the fact that, by the pseudo-second-order model and the pseudofirst-order model, the mount of metal ions adsorbed was inversely correlated with the number of active sites on the surface of the adsorbent material. according to the intraparticle diffusion model, the v+5 finding may be explained by the extremely quick movement of solute molecules and ions within the border layer of the adsorbent material, as well as by the surface diffusion of those solute particles towards the adsorption pores. the results of the kinetic investigation, with a low correlation coefficient (r2), were in agreement with the elovich model, which postulates a gradual concentrationdependent decline in the amount of cd, ni, and v ions adsorbed. n. a. jawad and t. m. naife / iraqi journal of chemical and petroleum engineering 23,4 (2022) 59 69 65 table 3. constant values of pseudo-first-order, pseudo-second-order, elovich, and intra particle-diffusion models for cadmium, nickel, and vanadium ions adsorption using go metal pseudo-first-order model pseudo-second-order model elovich model intra-particle diffusion qe k1 r2 qe k2 r2 ⍺ 𝜷 r2 kp c r2 cd 132.5407 -0.000205 0.9746 100.8065 0.00054 0.9783 14.477 0.053 0.9584 6.9489 10.2845 0.911 ni 88.3221 -0.000159 0.9147 111.9821 0.00031 0.9220 12.584 0.049 0.8732 7.7065 4.9632 0.8799 v 189.614 -0.000214 0.9432 118.0638 0.00019 0.8747 10.469 0.050 0.8727 7.7582 -0.4934 0.9481 fig. 7. pseudo first order kinetic model of go for (a. cadmium, b. nickel, and c. vanadium) adsorption fig. 8. pseudo second order kinetic model of go for (a. cadmium, b. nickel, and c. vanadium) adsorption fig. 9. elovich kinetic model of go for (a. cadmium, b. nickel, and c. vanadium) adsorption fig. 10. intra-particle diffusion kinetic model of go for (a. cadmium, b. nickel, and c. vanadium) adsorption 3.4. adsorption thermodynamic study the values of thermodynamic functions, which are vital in defining many processes, notably the adsorption process, may be used to understand the types of driving forces and the reaction's direction. additionally, they provide a convincing justification for the uniformity of molecules in diverse systems as a consequence of numerous molecular manipulations. the gibbs free energy (∆𝐺) is the function that determines whether the reaction or change is spontaneous or not. the value of enthalpy (∆𝐻) represents a straightforward measurement of the interference forces between the adsorbed particle and the surface of the adsorbent, while the value of 0 20 40 60 80 100 120 140 160 180 200 -3 -2 -1 0 1 2 3 4 5 ln ( q e -q t) time (min) y= -0.037x + 4.8869 r 2 = 0.9746 a. cadmium 0 20 40 60 80 100 120 140 160 180 200 0 1 2 3 4 5 ln ( q e -q t) time (min) y= -0.0288 + 4.481 r 2 = 0.9147 b. nickel 0 20 40 60 80 100 120 140 160 180 200 -3 -2 -1 0 1 2 3 4 5 ln ( q e -q t) time (min) y= -0.0384x + 5.245 r 2 = 0.9432 c.vanadium 0 20 40 60 80 100 120 140 160 180 200 0.0 0.5 1.0 1.5 2.0 t/ q t time (min) y= 0.00992x + 0.1836 r 2 = 0.97826 a. cadmium 0 20 40 60 80 100 120 140 160 180 200 0.0 0.5 1.0 1.5 2.0 t/ q t time (min) y= 0.0089x + 0.2600 r 2 = 0.9220 b. nickel 0 20 40 60 80 100 120 140 160 180 200 0.0 0.5 1.0 1.5 2.0 t/ q t time (min) y= 0.0085x + 0.3761 r 2 = 0.8747 c. vanadium 0 1 2 3 4 5 6 0 20 40 60 80 100 q t ln t y=18.9615x 5.1164 r 2 = 0.9584 a. cadmium 0 1 2 3 4 5 6 0 20 40 60 80 100 q t ln t y= 20.4958x 9.9981 r 2 = 0.87323 b. nickel 0 1 2 3 4 5 6 0 20 40 60 80 100 q t ln t y= 19.9611x 12.8821 r 2 = 0.8727 c. vanadium 0 2 4 6 8 10 12 14 0 20 40 60 80 100 q t t 0.5 y= 6.9489x + 10.2845 r 2 = 0.91101 a. cadmium 0 2 4 6 8 10 12 14 0 20 40 60 80 100 q t t 0.5 y= 7.7065x + 4.9632 r 2 = 0.8799 b. nickel 0 2 4 6 8 10 12 14 0 20 40 60 80 100 q t t 0.5 y= 7.75818x 0.4934 r 2 = 0.94807 c. vanadium n. a. jawad and t. m. naife / iraqi journal of chemical and petroleum engineering 23,4 (2022) 59 69 66 entropy (∆𝑆) represents a measure of the anarchism and randomness of the molecules on the adsorption surface. the van't hoff relation equation (15), which was developed by dutch scientist jacobus henricus van't hoff in 1884, might be used to calculate the thermodynamic variables. 𝑙𝑛𝑘𝑎𝑑 = − ∆𝐻 𝑅 1 𝑇 + ∆𝑆 𝑅 (15) where 𝑘𝑎𝑑: adsorption thermodynamic equilibrium coefficient (dimensionless), r: universal gas constant (8.3144 j mol-1 k-1), 𝑇: absolute temperature (k), 𝛥𝐻: enthalpy change (j mol-1), and 𝛥𝑆: the entropy change (j mol-1 k-1). equation (16) calculates the adsorption thermodynamic equilibrium coefficient. 𝑘𝑎𝑑 = 𝑞𝑒 𝐶𝑒 (16) by plotting the relation between 𝑙𝑛𝑘𝑎𝑑 and 1 𝑇 , it gives a straight line of slope represented by ∆𝐻 and ∆𝑆 can be calculated from the intercept. equation (17) below may be used to get the system's gibbs free energy (g): ∆𝐺 = ∆𝐻 − 𝑇∆𝑆 (17) fig. 11 show the outcomes of the thermodynamic analysis, and tables that give the values of the thermodynamic functions are listed in table 4. it is well known that the thermodynamic functions (𝛥𝐻, 𝛥𝑆, 𝛥𝐺) are essential for figuring out the spontaneous process and describing how metal ions adsorb on the surface of adsorbent media. on the other hand, this method may be used to precisely characterize the situation of interference between the two surfaces of the solid phase and the liquid phase. according to the obtained information from the figures and tables above showing the adsorption process of cd, ni, and v metals on the surface of go, the thermodynamic equilibrium coefficient kad is demonstrated to decrease with rising temperature t. this might be because when the temperature is elevated, the bond between the ions of the adsorbent metals and the active sites on the adsorption surface breaks, allowing the ions to be freed and reintroduced into the solution. the enthalpy function's values that influenced 𝛥𝐻, were all negative. this figure indicates the process of investigating the exothermic adsorption of heavy metal ions on surfaces of adsorption materials. chemical adsorption causes go to absorb cd, ni, and v (chemisorption). an augmentation of interaction between the adsorbed metal ions and the adsorption surface as a result of a chemical reaction and the formation of a new type of electronic bonds with the functional groups on the surface of the adsorbent material are both indicated by an enthalpy value greater than 40 (kj mol-1). the negative value of the entropy function changing 𝛥𝑆 for all adsorption tests using all the utilized adsorbent materials illustrates the reduction in randomness state in the surface overlap between the solid phase and the liquid phase throughout the adsorption process. this number also represents the three heavy metal ions' surface affinities for adsorption from the solution. because the entropy function has a negative value during the adsorption process, the molecules are dispersed more evenly than they are while they are in solution. as a consequence of the exchange of heavy metal ions with less mobile ions on the surface of the material, entropy is reduced during the adsorption process. additionally, it was shown that under the experimental conditions investigated, where the values of gibbs free energy changing 𝛥𝐺 were negative, the process of adsorption for heavy metal ions examined using adsorption materials is spontaneous. this suggests that the cd, ni, and v ion adsorption on the adsorption sites in the adsorbent go is an energy-free spontaneous process. additionally, the fact that the negative value of compressive energy decreases as system temperature rises suggests that spontaneity decreases and that adsorption favor colder temperatures. fig. 11. thermodynamic behaviors of (a. cadmium, b. nickel, and c. vanadium) adsorption using go 0.0031 0.0032 0.0033 0.0034 0.00 0.65 1.30 1.95 2.60 ln k a d 1/t a. cadmium 0.0031 0.0032 0.0033 0.0034 0.00 0.75 1.50 2.25 3.00 ln k a d 1/t b. nickel 0.0031 0.0032 0.0033 0.0034 0.00 0.75 1.50 2.25 3.00 ln k a d 1/t c. vanadium n. a. jawad and t. m. naife / iraqi journal of chemical and petroleum engineering 23,4 (2022) 59 69 67 table 4. thermodynamic behaviors of cadmium, nickel, and vanadium adsorption using go metal temperature, (°c) alteration of enthalpy ∆𝑯, )1-kj.mol( alteration of entropy ∆𝑺, )1-. k1-j.mol( alteration of gibbs free energy ∆𝑮, )1-kj.mol( +2cd 20 -48.1719 -144.0284 -5.9498 25 -5.7325 30 -4.1775 35 -3.5501 40 -2.9997 45 -2.3674 50 -1.90187 +2ni 20 -63.9944 -196.0374 -6.7031 25 -5.7325 30 -4.5732 35 -3.2412 40 -2.3302 45 -1.6367 50 -1.0889 +5v 20 -45.3358 -132.3480 -6.3015 25 -6.0514 30 -5.5354 35 -4.4420 40 -3.9462 45 -3.19475 50 -2.5364 4conclusions to create nano graphene oxide (go) from graphite powder in this work, the hummers process was modified. metal ions' enhanced ability to bind to go is owing to their characteristics of hydrophilic and the oxygencontaining functional group's presence. since they share an electron pair, these groups may effectively bind metal ions to create metal complexes. the removal efficiency of all metal ions rose as the temperature decreased, reaching a maximum of 20 °c and declining to 50 °c. when the initial cd, ni, and v concentration is 100 (mg l-1) the concentrations of equilibrium values were, respectively, 8.9, 4.9, and 6.9 (mg l-1). for all heavy metal ions as the initial concentration value increases for adsorbent metals, the percentage removal decreases. the langmuir model may be explained by the adsorption isotherms; they show that heavy metal ions adsorb on monolayer-coated go graphene sheets. since it was fitted, the kinetic analysis implies that chemical adsorption (chemisorption), metal ion adsorption on go is regulated by the complexation of the surface for heavy metal ions containing oxygen groups on the go surface. for cd, and ni ion to the pseudo-second-order kinetic model, and v ion to intraparticle diffusion. the thermodynamic equilibrium coefficient kad for the adsorption of cd, ni, and v ions declines with increasing temperature t, and the values of the enthalpy function ∆h are negative, suggesting that the process is exothermic. a negative entropy function, ∆s, causes the reduction in randomness. in addition, the adsorption material ions were spontaneous, with negative gibbs free energy values influencing ∆g. references [1] d. k. tiku, a. kumar, s. sawhney, v. p. singh, and r. kumar, “effectiveness of treatment technologies for wastewater pollution generated by indian pulp mills,” environ monit assess, vol. 132, no. 1–3, pp. 453–466, sep. 2007. [2] h. m. rashid and a. a.h. faisal, “removal of dissolved cadmium ions from contaminated wastewater using raw scrap zero-valent iron and zero valent aluminum as locally available and inexpensive sorbent wastes,” ijcpe, vol. 19, no. 4, pp. 39–45, dec. 2018, doi: 10.31699/ijcpe.2018.4.5. [3] i. y. el-sherif, s. tolani, k. ofosu, o. a. mohamed, and a. k. wanekaya, “polymeric nanofibers for the removal of cr(iii) from tannery waste water,” journal of environmental management, vol. 129, pp. 410–413, nov. 2013, doi: 10.1016/j.jenvman.2013.08.004. [4] d. gola, a. malik, z. a. shaikh, and t. r. sreekrishnan, “impact of heavy metal containing wastewater on agricultural soil and produce: relevance of biological treatment,” environ. process., vol. 3, no. 4, pp. 1063–1080, dec. 2016, doi: 10.1007/s40710-016-0176-9. [5] m. taseidifar, f. makavipour, r. m. pashley, and a. f. m. m. rahman, “removal of heavy metal ions from water using ion flotation,” environmental technology & innovation, vol. 8, pp. 182–190, nov. 2017, doi: 10.1016/j.eti.2017.07.002. [6] i. demiral, c. samdan, and h. demiral, “enrichment of the surface functional groups of activated carbon by modification method,” surfaces and interfaces, vol. 22, p. 100873, feb. 2021, doi: 10.1016/j.surfin.2020.100873. [7] w. zeng, w. guo, b. li, z. wei, d. d. dionysiou, and r. xiao, “kinetics and mechanistic aspects of removal of heavy metal through gas-liquid sulfide precipitation: a computational and experimental study,” journal of hazardous materials, vol. 408, p. 124868, apr. 2021. [8] h. khani, m. k. rofouei, p. arab, v. k. gupta, and z. vafaei, “multi-walled carbon nanotubes-ionic liquid-carbon paste electrode as a super selectivity sensor: application to potentiometric monitoring of mercury ion(ii),” journal of hazardous materials, vol. 183, no. 1–3, pp. 402–409, nov. 2010. https://link.springer.com/article/10.1007/s10661-006-9548-3 https://link.springer.com/article/10.1007/s10661-006-9548-3 https://link.springer.com/article/10.1007/s10661-006-9548-3 https://link.springer.com/article/10.1007/s10661-006-9548-3 https://link.springer.com/article/10.1007/s10661-006-9548-3 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/507 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/507 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/507 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/507 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/507 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/507 https://www.sciencedirect.com/science/article/pii/s030147971300515x https://www.sciencedirect.com/science/article/pii/s030147971300515x https://www.sciencedirect.com/science/article/pii/s030147971300515x https://www.sciencedirect.com/science/article/pii/s030147971300515x https://www.sciencedirect.com/science/article/pii/s030147971300515x https://www.sciencedirect.com/science/article/pii/s030147971300515x https://link.springer.com/article/10.1007/s40710-016-0176-9 https://link.springer.com/article/10.1007/s40710-016-0176-9 https://link.springer.com/article/10.1007/s40710-016-0176-9 https://link.springer.com/article/10.1007/s40710-016-0176-9 https://link.springer.com/article/10.1007/s40710-016-0176-9 https://link.springer.com/article/10.1007/s40710-016-0176-9 https://www.sciencedirect.com/science/article/abs/pii/s2352186417301098 https://www.sciencedirect.com/science/article/abs/pii/s2352186417301098 https://www.sciencedirect.com/science/article/abs/pii/s2352186417301098 https://www.sciencedirect.com/science/article/abs/pii/s2352186417301098 https://www.sciencedirect.com/science/article/abs/pii/s2352186417301098 https://www.sciencedirect.com/science/article/abs/pii/s2468023020308658 https://www.sciencedirect.com/science/article/abs/pii/s2468023020308658 https://www.sciencedirect.com/science/article/abs/pii/s2468023020308658 https://www.sciencedirect.com/science/article/abs/pii/s2468023020308658 https://www.sciencedirect.com/science/article/abs/pii/s2468023020308658 https://www.sciencedirect.com/science/article/abs/pii/s0304389420328594 https://www.sciencedirect.com/science/article/abs/pii/s0304389420328594 https://www.sciencedirect.com/science/article/abs/pii/s0304389420328594 https://www.sciencedirect.com/science/article/abs/pii/s0304389420328594 https://www.sciencedirect.com/science/article/abs/pii/s0304389420328594 https://www.sciencedirect.com/science/article/abs/pii/s0304389420328594 https://www.sciencedirect.com/science/article/abs/pii/s0304389410009246 https://www.sciencedirect.com/science/article/abs/pii/s0304389410009246 https://www.sciencedirect.com/science/article/abs/pii/s0304389410009246 https://www.sciencedirect.com/science/article/abs/pii/s0304389410009246 https://www.sciencedirect.com/science/article/abs/pii/s0304389410009246 https://www.sciencedirect.com/science/article/abs/pii/s0304389410009246 n. a. jawad and t. m. naife / iraqi journal of chemical and petroleum engineering 23,4 (2022) 59 69 68 [9] t. a. saleh and v. k. gupta, “synthesis and characterization of alumina nano-particles polyamide membrane with enhanced flux rejection performance,” separation and purification technology, vol. 89, pp. 245–251, mar. 2012, doi: 10.1016/j.seppur.2012.01.039. [10] a. e. burakov et al., “adsorption of heavy metals on conventional and nanostructured materials for wastewater treatment purposes: a review,” ecotoxicology and environmental safety, vol. 148, pp. 702–712, feb. 2018, doi: 10.1016/j.ecoenv.2017.11.034. [11] basma abbas abdel majeed, raheem jameel muhseen, and nawras jameeljassim, “adsorption of diclofenac sodium and ibuprofen by bentonite polyureaformaldehyde thermodynamics and kinetics study,” iraqi journal of chemical and petroleum engineering, vol. 19, no. 1, pp. 29–43, mar. 2018. [12] x. wang et al., “synthesis of novel nanomaterials and their application in efficient removal of radionuclides,” sci. china chem., vol. 62, no. 8, pp. 933–967, aug. 2019, doi: 10.1007/s11426-019-94924. [13] c. guerrero-fajardo, l. giraldo, and j. morenopiraján, “preparation and characterization of graphene oxide for pb(ii) and zn(ii) ions adsorption from aqueous solution: experimental, thermodynamic and kinetic study,” nanomaterials, vol. 10, no. 6, p. 1022, may 2020, doi: 10.3390/nano10061022. [14] q. kong et al., “relations between metal ion characteristics and adsorption performance of graphene oxide: a comprehensive experimental and theoretical study,” separation and purification technology, vol. 232, p. 115956, feb. 2020, doi: 10.1016/j.seppur.2019.115956. [15] w. s. hummers and r. e. offeman, “preparation of graphitic oxide,” j. am. chem. soc., vol. 80, no. 6, pp. 1339–1339, mar. 1958, doi: 10.1021/ja01539a017. [16] c. bulin et al., “magnetic graphene oxide nanocomposite: one-pot preparation, adsorption performance and mechanism for aqueous mn(ⅱ) and zn(ⅱ),” journal of physics and chemistry of solids, vol. 156, p. 110130, sep. 2021, doi: 10.1016/j.jpcs.2021.110130. [17] j. chen, b. yao, c. li, and g. shi, “an improved hummers method for eco-friendly synthesis of graphene oxide,” carbon, vol. 64, pp. 225–229, nov. 2013, doi: 10.1016/j.carbon.2013.07.055. [18] s. s. türkaslan, ş. s. ugur, b. e. türkaslan, and n. fantuzzi, “evaluating the x-ray-shielding performance of graphene-oxide-coated nanocomposite fabric,” materials, vol. 15, no. 4, p. 1441, feb. 2022, doi: 10.3390/ma15041441. [19] s. k. tiwari, a. huczko, r. oraon, a. de adhikari, and g. c. nayak, “facile electrochemical synthesis of few layered graphene from discharged battery electrode and its application for energy storage,” arabian journal of chemistry, vol. 10, no. 4, pp. 556–565, may 2017, doi: 10.1016/j.arabjc.2015.08.016. [20] h. li and z. wei, “impacts of modified graphite oxide on crystallization, thermal and mechanical properties of polybutylene terephthalate,” polymers, vol. 13, no. 15, p. 2431, jul. 2021, doi: 10.3390/polym13152431. [21] m. parastar, s. sheshmani, and s. shokrollahzadeh, “cross-linked chitosan into graphene oxide-iron(iii) oxide hydroxide as nano-biosorbent for pd(ii) and cd(ii) removal,” international journal of biological macromolecules, vol. 166, pp. 229–237, jan. 2021, doi: 10.1016/j.ijbiomac.2020.10.160. [22] zainab jabbar shadhan and mohammed n. abbas, “removal of heavy metals from refineries wastewater,” master of science in environmental engineering, mustansiriyah university, iraq, 2021. [23] e. n. mahmoud, f. y. fayed, k. m. ibrahim, and s. jaafreh, “removal of cadmium, copper, and lead from water using bio-sorbent from treated olive mill solid residue,” environmental health insights, vol. 15, p. 117863022110531, jan. 2021, doi: 10.1177/11786302211053176. [24] d. k. venkata ramana, j. s. yu, and k. seshaiah, “silver nanoparticles deposited multiwalled carbon nanotubes for removal of cu(ii) and cd(ii) from water: surface, kinetic, equilibrium, and thermal adsorption properties,” chemical engineering journal, vol. 223, pp. 806–815, may 2013, doi: 10.1016/j.cej.2013.03.001. [25] a. r. kaveeshwar, s. k. ponnusamy, e. d. revellame, d. d. gang, m. e. zappi, and r. subramaniam, “pecan shell based activated carbon for removal of iron(ii) from fracking wastewater: adsorption kinetics, isotherm and thermodynamic studies,” process safety and environmental protection, vol. 114, pp. 107–122, feb. 2018, doi: 10.1016/j.psep.2017.12.007. [26] d. j. o’shannessy and d. j. winzor, “interpretation of deviations from pseudo-first-order kinetic behavior in the characterization of ligand binding by biosensor technology,” analytical biochemistry, vol. 236, no. 2, pp. 275–283, may 1996, doi: 10.1006/abio.1996.0167. https://www.sciencedirect.com/science/article/abs/pii/s1383586612000664 https://www.sciencedirect.com/science/article/abs/pii/s1383586612000664 https://www.sciencedirect.com/science/article/abs/pii/s1383586612000664 https://www.sciencedirect.com/science/article/abs/pii/s1383586612000664 https://www.sciencedirect.com/science/article/abs/pii/s1383586612000664 https://www.sciencedirect.com/science/article/abs/pii/s1383586612000664 https://www.sciencedirect.com/science/article/abs/pii/s0147651317307881 https://www.sciencedirect.com/science/article/abs/pii/s0147651317307881 https://www.sciencedirect.com/science/article/abs/pii/s0147651317307881 https://www.sciencedirect.com/science/article/abs/pii/s0147651317307881 https://www.sciencedirect.com/science/article/abs/pii/s0147651317307881 https://www.sciencedirect.com/science/article/abs/pii/s0147651317307881 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/223 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/223 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/223 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/223 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/223 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/223 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/223 https://link.springer.com/article/10.1007/s11426-019-9492-4 https://link.springer.com/article/10.1007/s11426-019-9492-4 https://link.springer.com/article/10.1007/s11426-019-9492-4 https://link.springer.com/article/10.1007/s11426-019-9492-4 https://link.springer.com/article/10.1007/s11426-019-9492-4 https://www.mdpi.com/2079-4991/10/6/1022 https://www.mdpi.com/2079-4991/10/6/1022 https://www.mdpi.com/2079-4991/10/6/1022 https://www.mdpi.com/2079-4991/10/6/1022 https://www.mdpi.com/2079-4991/10/6/1022 https://www.mdpi.com/2079-4991/10/6/1022 https://www.mdpi.com/2079-4991/10/6/1022 https://www.sciencedirect.com/science/article/abs/pii/s1383586619328849 https://www.sciencedirect.com/science/article/abs/pii/s1383586619328849 https://www.sciencedirect.com/science/article/abs/pii/s1383586619328849 https://www.sciencedirect.com/science/article/abs/pii/s1383586619328849 https://www.sciencedirect.com/science/article/abs/pii/s1383586619328849 https://www.sciencedirect.com/science/article/abs/pii/s1383586619328849 https://pubs.acs.org/doi/pdf/10.1021/ja01539a017 https://pubs.acs.org/doi/pdf/10.1021/ja01539a017 https://pubs.acs.org/doi/pdf/10.1021/ja01539a017 https://pubs.acs.org/doi/pdf/10.1021/ja01539a017 https://www.sciencedirect.com/science/article/abs/pii/s0022369721001967 https://www.sciencedirect.com/science/article/abs/pii/s0022369721001967 https://www.sciencedirect.com/science/article/abs/pii/s0022369721001967 https://www.sciencedirect.com/science/article/abs/pii/s0022369721001967 https://www.sciencedirect.com/science/article/abs/pii/s0022369721001967 https://www.sciencedirect.com/science/article/abs/pii/s0022369721001967 https://www.sciencedirect.com/science/article/abs/pii/s0008622313006891 https://www.sciencedirect.com/science/article/abs/pii/s0008622313006891 https://www.sciencedirect.com/science/article/abs/pii/s0008622313006891 https://www.sciencedirect.com/science/article/abs/pii/s0008622313006891 https://www.mdpi.com/1996-1944/15/4/1441 https://www.mdpi.com/1996-1944/15/4/1441 https://www.mdpi.com/1996-1944/15/4/1441 https://www.mdpi.com/1996-1944/15/4/1441 https://www.mdpi.com/1996-1944/15/4/1441 https://www.sciencedirect.com/science/article/pii/s1878535215002567 https://www.sciencedirect.com/science/article/pii/s1878535215002567 https://www.sciencedirect.com/science/article/pii/s1878535215002567 https://www.sciencedirect.com/science/article/pii/s1878535215002567 https://www.sciencedirect.com/science/article/pii/s1878535215002567 https://www.sciencedirect.com/science/article/pii/s1878535215002567 https://www.sciencedirect.com/science/article/pii/s1878535215002567 https://www.mdpi.com/2073-4360/13/15/2431 https://www.mdpi.com/2073-4360/13/15/2431 https://www.mdpi.com/2073-4360/13/15/2431 https://www.mdpi.com/2073-4360/13/15/2431 https://www.mdpi.com/2073-4360/13/15/2431 https://www.sciencedirect.com/science/article/abs/pii/s014181302034808x https://www.sciencedirect.com/science/article/abs/pii/s014181302034808x https://www.sciencedirect.com/science/article/abs/pii/s014181302034808x https://www.sciencedirect.com/science/article/abs/pii/s014181302034808x https://www.sciencedirect.com/science/article/abs/pii/s014181302034808x https://www.sciencedirect.com/science/article/abs/pii/s014181302034808x https://www.iasj.net/iasj/download/c512f2168fc1c2e3 https://www.iasj.net/iasj/download/c512f2168fc1c2e3 https://www.iasj.net/iasj/download/c512f2168fc1c2e3 https://www.iasj.net/iasj/download/c512f2168fc1c2e3 https://journals.sagepub.com/doi/full/10.1177/11786302211053176 https://journals.sagepub.com/doi/full/10.1177/11786302211053176 https://journals.sagepub.com/doi/full/10.1177/11786302211053176 https://journals.sagepub.com/doi/full/10.1177/11786302211053176 https://journals.sagepub.com/doi/full/10.1177/11786302211053176 https://journals.sagepub.com/doi/full/10.1177/11786302211053176 https://www.sciencedirect.com/science/article/abs/pii/s1385894713003252 https://www.sciencedirect.com/science/article/abs/pii/s1385894713003252 https://www.sciencedirect.com/science/article/abs/pii/s1385894713003252 https://www.sciencedirect.com/science/article/abs/pii/s1385894713003252 https://www.sciencedirect.com/science/article/abs/pii/s1385894713003252 https://www.sciencedirect.com/science/article/abs/pii/s1385894713003252 https://www.sciencedirect.com/science/article/abs/pii/s1385894713003252 https://www.sciencedirect.com/science/article/abs/pii/s095758201730410x https://www.sciencedirect.com/science/article/abs/pii/s095758201730410x https://www.sciencedirect.com/science/article/abs/pii/s095758201730410x https://www.sciencedirect.com/science/article/abs/pii/s095758201730410x https://www.sciencedirect.com/science/article/abs/pii/s095758201730410x https://www.sciencedirect.com/science/article/abs/pii/s095758201730410x https://www.sciencedirect.com/science/article/abs/pii/s095758201730410x https://www.sciencedirect.com/science/article/abs/pii/s095758201730410x https://www.sciencedirect.com/science/article/abs/pii/s0003269796901670 https://www.sciencedirect.com/science/article/abs/pii/s0003269796901670 https://www.sciencedirect.com/science/article/abs/pii/s0003269796901670 https://www.sciencedirect.com/science/article/abs/pii/s0003269796901670 https://www.sciencedirect.com/science/article/abs/pii/s0003269796901670 https://www.sciencedirect.com/science/article/abs/pii/s0003269796901670 n. a. jawad and t. m. naife / iraqi journal of chemical and petroleum engineering 23,4 (2022) 59 69 69 ناعيالنمذجة الرياضية والحركية الزالة ايونات المعادن من مياه مخلفات الصرف الص طارق محمد نايف ونزار عبد المهدي جواد الهندسة الكيمياوية/ كلية الهندسة/ جامعة بغدادقسم الخالصة الة الستخدامه في عملية امتزاز الدفعات الز ( (goالهدف من الدراسة هو إنتاج نانو اوكسيد الجرافين مت ( من مياه مخلفات الصرف الصناعي. تv+5 ، والفاناديوم ni+2النيكل ،cd+2المعادن الثقيلة )الكادميوم م / لترلغ( م800-100( درجة مئوية وتغير التركيز االبتدائي )50-20تأثيركل من تغير درجة الحرارة )دراسة ة على عملية االمتزاز. تم استخدام محلول مائي من األيونات محاكي لعينات المخلفات لتحديد متساوي درج تمت دراسة عملية االمتصاص وبعد جمع البيانات التجريبية، ، (adsorption isotherms)حرارة االمتصاص و langmuir(: adsorption isothermsحركًيا وديناميكًيا حرارًيا. تم استخدام نماذج متساوية الحرارة ) freundlich وtemkin لى سطح النيكل والفاناديوم ع ،هرت النتائج أن أيونات الكادميوملتناسب البيانات، وأظ . 0.999البالغة (2r)مع معامالت االرتباط langmuirئم مع نموذج االمتصاص نانو اوكسيد الجرافين تتال ة، حراري أظهرت النماذج الحركية التي تمت دراستها أنه تم اتباع نموذج من الدرجة الثانية الزائفة وديناميكا أثر تسالب. باإلضافة إلى ذلك، s∆سالبة، وانخفاض العشوائية بسبب h∆وكانت العملية طاردة للحرارة بسبب السلبية. g∆االمتزاز التلقائي أليونات المعادن بقيم انية، لدرجة الثنموذج بسيدو ا ،نموذج النموي ، مياه الصرف الصحي،ايونات المعادن الثقيلة ،ة: نانو أكسيد الجرافينلادالكلمات ال .دراسة الديناميكا الحرارية available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.21 no.3 (september 2020) 45 – 49 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: saleem mohammed obyed , email: saleem_mo71@yahoo.com, name: mohammed saadi hameed, email: msha72@yahoo.com , name: abdulkareem dahash, email: kareem_raad@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. studying thermal cracking behavior of vacuum residue saleem mohammed obyed, mohammed saadi hameed and abdulkareem dahash affat alnahrain university engineering college abstract in the oil industry, the processing of vacuum residue has an important economic and environmental benefit. this work aims to produce industrial petroleum coke with light fuel fractions (gasoline, kerosene , gas oil) as the main product and de asphalted oil (dao) as a side production from treatment secondary product matter of vacuum residue. vacuum residue was produced from the bottom of vacuum distillation unit of the crude oil. experimentally, the study investigated the effect of the thermal conversion process on (vacuum residue) as a raw material at temperature reaches to 500 °c, pressure 20 atm. and residence time for about 3 hours. the first step of this treatment is constructing a carbon steel batch reactor its volume about 700 ml, occupied with auxiliary control devices, joined together with an atmospheric distillation unit. the amounts of light fuel fraction products are 2 vol. % for light gasoline, 4 vol. % for heavy gasoline 17 vol. % for kerosene and 24 vol. % for diesel oil. the second step was the treatment the residue matter from first step, in order to separate the petroleum coke matter from asphaltene matter by solvent deasphalting matter (propane) to prepare de asphalted oil (dao). the amount of de asphalted oil is about 15 vol. %, leaving asphaltene with impurities to precipitate at the bottom of the reactor and these materials consist of the petroleum coke structure. the petroleum coke separate and calcined at approximately (1000 1100) °c, to eliminate the reminder of volatile matter from the industrial coke and reach to commercial property. keywords: vacuum residue, cracking, coking, distillation received on 04/01/2020, accepted on 04/06/2020, published on 30/09/2020 https://doi.org/10.31699/ijcpe.2020.3.6 1introduction the physical and chemical properties of crude oils are influenced by boiling point of constituents, it is therefore important to characterize the heaviest fractions of crude oils [1]. the conversion process is intended to minimize the production of heavy fractions from crude oil; the intended objective of conversion is to convert of all heavy products [2]. atmospheric and vacuum residue units in petroleum refineries contains large amount of impurities (sulfur, nitrogen, metals and asphaltenes). the rate of conversion is limited by the presence of asphaltenes which tend to concentrate and precipitate in the heavy product cuts, thus rending them unsuitable for consumption [3]. asphaltenes are dark brown solids, usually leave carbonaceous matter on heating; they are made up of complex structure aromatic compounds consist of a number of benzene rings, known as polynuclear aromatic compound layers joined with saturated links, their molecular weights span a wide range, from a few hundred to several million [4]. they are found in the heavy petroleum cuts and their presence is undesirable they cause catalyst deactivation and coke deposition, besides causing environmental problems. liquefied petroleum fractions are used in deasphalting residues process [5]. the presence of asphaltene and resins residue can create many problems in properties of light production; they lead to coke formation in products [6]. resins are polar molecules in the molecular weight range of 500-1000; the resin molecules surround the asphaltene micelles and suspend them in liquid oil [1, 7]. the thermal cracking begins as soon as petroleum feed stock reaches about 400 to 420 °c [8, 9], the severity of the process depends on the temperature and the residence time [10, 11]. to eliminate all lights matter from industrial coke it must be calcined [12, 13]. coking, in particular, is recognized not only for the marked reduction in heavy fuel oil produced but also as a method of producing additional light products. coke contains about 83% carbon and 6% hydrogen and balance with impurities [14, 15]. the major uses of industrial petroleum coke are as domestic fuel without calcining, manufacture of anodes, graphite, electrodes and manufacture of metals [16, 17]. mori, et.al studied the effect of temperature range between (400-630) °c on heavy oil cracking, its specific gravity of 0.9 to 1.1 in batch reactor to produce light fractions and by product which heated to 800 – 1200 °c. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:saleem_mo71@yahoo.com mailto:msha72@yahoo.com mailto:kareem_raad@yahoo.com http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2020.3.6 s. m. obyed et al. / iraqi journal of chemical and petroleum engineering 21,3 (2020) 45 49 46 syamsuddin, et.al studied the effect of temperature and type of catalyst of atmospheric crude oil residue in batch reactor at 350 °c for 3 hours residence time and the conversion reaches to 52-65 respectively and the gasoline yield reaches to 7 – 14. lopes, et.al studied the transforms heavy oil to lighter crude oil at temperature 480540°c, the produces less sulfur content. kondo et.al studied the effect of temperature on vacuum residue cracking in batch reactor at 400-440 °c; the main products were coke. del bianco et.al studied the kinetic for thermal cracking of petroleum vacuum residue matter at 410-470°c and reaction reaches to 120 minute, the activation energy reaches to 14 kcal / mol. the objective of this work was to study the effect of the temperature on conversion process on (vacuum residue) to temperature reaches to 500 °c in order to production of industrial petroleum coke from vacuum residue matter with distillate fractions as a main production and de asphalted oil (dao as a secondary production. 2experimental work 2.1. materials a. vacuum residue the heavy raw material, which was used as a raw material for production industrial petroleum coke in this work, was vacuum residue matter, which was obtained from the bottom of vacuum distillation tower of crude oil, whose major physical and chemical properties were listed in table 1. table 1. the major physical and chemical properties of vacuum residue feed stock temperature cut °c density gm./cc api viscosity 100 ° c cst sulfur wt.% content conradson carbon index molecular weight gm/mol 540 1.048 3.5 4500 5.78 22.6 510 2.2. procedure of the work a. pyrolysis of vacuum residue the process of thermal treatment for vacuum residue feed was performed in designed batch reactor as shown in fig. 1, and fig. 2. the reactor was made of carbon steel and its volume about 700 ml, this reactor contains two valves, the upper one was used for inlet raw materials and down was used for discharge product. the reactor occupied with many auxiliary parts, like (electrical heater, thermocouple, timer, temperature controller, and hood). the feed (vacuum residue) is introduced in the desired quantity (100 ml) in the reactor unit. the reactor was joined together with astm distillation unit which consist of (electrical and condenser) to eliminate part amount of volatile matter (gasoline, kerosene and gas oil) from feed, according to its boiling point with a temperature reaches to 350 °c and atmospheric pressure, in order to collect the volatility light petroleum fractions. firstly the reactor is heated with introduce nitrogen to remove the air from it, so that no explosive mixture forms with the stock vapors. the electrical heater used to heat the feed to desired temperature until 350 °c in the reactor unit and atmospheric pressure. at temperature 30 °c separation of the distillate fractions begins, which increases as the temperature of the reactor rises to 350 °c. the volume of distillated fractions that obtained from this step is about 47%. b. coking of asphaltene when the temperature rises between 350 °c and 500 °c, for the residue which obtained from pyrolysis of vacuum residue step, the deasphalted oil (dao) was formed. the residual amounts in reactor (dao, asphaltene and impurities) were treated with light petroleum solvent for extraction the remains oil. light paraffin such as propane in liquid form used to dissolve the deasphalted oil (dao) its volume about 15 % from the feed stock and precipitate asphaltene with impurities. leaving last heavy distillate matter (asphaltene) to separate and precipitate with impurities, like (sulfur, nitrogen, salt, sediments, metals and others) in reactor its volume about 38 % from the feed stock (vacuum residue). the thermal treatment for the precipitate asphaltene with impurities will be occurred at constant temperature 500 °c inside the reactor, which controlled by temperature controller and pressure about 20 atmosphere with residence time about 3 hours in order to production petroleum coke. additional heating used in coke reactor was needed to complete the coking process, dry and calcination the coke. the petroleum coke calcined to temperature (1000 – 1100) °c to reduce the volatile matter to a very low level and complete the carbonization reactions in petroleum coke. after completion of calcination, the temperature of the reactor lowered and the extraction of coke is begun. fig. 1. laboratory batch reactor devices s. m. obyed et al. / iraqi journal of chemical and petroleum engineering 21,3 (2020) 45 49 47 fig. 2. flow diagram of experimental batch reactor unit with controls system, 1-reactor 2-heater 3-valve 4thermocouple 5-timer 6temperature controller 7electrical source 8astm d-86 unit 3results and discussion the structures of the compounds in petroleum, such as vacuum residue which have boiling points above 540°c are highly complex and consist of oils, resins, and asphaltenes related to solubility in propane or light other hydrocarbon. 3.1. thermal cracking products a. atmospheric distillation astm d-86 for vacuum residue the results amount of distillation operation for vacuum residue which was needed to separate volatile matter, (gasoline, kerosene, and gas oil) from asphaltene and dao, which are shown in table 2. table 2. astm d-86 distillation for vacuum residue temperature °c 30 80 180 260 350 volume % 0 2 6 23 47 the initial boiling point of vacuum residue is 30 °c at this temperature separation of the distillate fractions begins, which increases as the temperature of the reactor rises to 350 °c. ' the volume of light gasoline fraction equal 2 vol.% until temperature equal to 80 °c, while the volume of heavy gasoline equal to 4 vol.% until temperature equal to 180 °c, also the volume of kerosene equal to 17 vol.% until temperature equal to 260 °c and the volume of diesel oil equal to 24 vol.% until temperature equal to 350 °c. the mentioned results are accepted with those mentioned by [15].the hardness and strength of industrial coke petroleum increase as the volatile matter was reduced. b. light distillate fractions the main of physical and chemical properties for light petroleum cuts with residue (asphltene and resin) that will be obtained after astm d-86 distillation of vacuum residue are shown in table 3. table 3. the physical and chemical properties for light petroleum cuts and residue characteristics light gasoline heavy gasoline kerosene diesel oil residue cut °c 30 80 80 180 180 260 260 350 over 500 volume % 2 4 17 24 53 density gm./cc 0.68 0.74 0.80 0.86 1.065 api 75.5 58.5 45 32 2 viscosity (100 °c) cst 0.8 1.5 1.6 1.1 2600 molecular weight. 75 117 175 225 560 sulfur content wt.% 0.05 0.1 0.5 3.35 5.9 the volume of all distillated fractions that obtained from this operation is about 47 vol. % and which is useful to use as automobile for gasoline cut and domestic uses for kerosene cut and diesel fuel for gas oil cut. c. deasphalted oil (dao) the main physical and chemical properties of deasphalted oil (dao) that will obtained after extraction operation by paraffin liquid (propane) for 53 vol.% of residue are shown in table 4. table 4. the main physical and chemical properties of deasphalted oil (dao) yield vol.% density gm. / cc viscosity (100 °c)cst sulfur content % conradson carbon% 15 0.973 120 1.06 8.5 the oil fraction in residue and the resin cut are soluble in propane but the asphltene fraction is insoluble in propane. the volume of dao equal to 15 vol. % and the volume of asphaltene with impurities equal to 38 vol. % from the vacuum residue and these consist of the raw materials of industrial petroleum coke. the dao has low sulfur and removed with asphaltene and also the dao used for production light fuel fractions (gasoline, kerosene and gas oil) by thermal cracking unit. the mentioned results are accepted with those mentioned by [3]. d. industrial petroleum coke the main physical and chemical properties of industrial petroleum coke which are obtained by solvent extraction process for residue are shown in table 5. table 5. analysis of calcined industrial petroleum coke volatile matters wt.% moisture content wt.% ash content wt.% sulfur content wt.% density gm./cc trace elements wt.% 0.75 0.9 0.38 3.65 2.06 0.25 s. m. obyed et al. / iraqi journal of chemical and petroleum engineering 21,3 (2020) 45 49 48 coke can be formed from the condensation of polynuclear aromatics such as nbutylnaphthlene.; asphaltene and aromatic are desirable feed stock for a good yield of industrial petroleum coke. the hardness and strength of industrial petroleum coke increases as the volatile matter is reduced. the presence of high amounts of asphaltenes in crude oil can create many problems in refinery production; they lead to coke formation with all products. there is a decrease in volatile material with rising calcination and for most purposes devolatilization and dehydrogenation are complete at temperature 1100 °c. the mentioned results are accepted with those mentioned by [18, 19]. 𝐶14 𝐻16 𝑐𝑜𝑛𝑑𝑒𝑛𝑠𝑎𝑡𝑖𝑜𝑛 → 𝐶22 𝐻16 + 2 𝐶3 𝐻8 (1)[18] 1 [18] nbutyl naphthlene coke propane resins and asphaltenes ℎ𝑒𝑎𝑡 → coke + lower boiling aromatics + un saturates and gas (2) [18] sulfur in feed stock though it increases petroleum coke yield, it forms complex with coke. the removal of sulfur from such product is rather impossible; calcination of coke again strengthens the bonds between sulfur and carbon. 4conclusions this work study the production of industrial petroleum coke as a main product with light fuel fractions and de asphalted oil as aside production from thermal treatment of vacuum residue as a raw material, so the conclusions from this study are:  production of industrial petroleum coke and distillate fractions (gasoline, kerosene and gas oil) with deasphalted oil (dao) can be obtained it, by thermal treatment process of secondary matter (vacuum residue)  possibilities uses of distillate fractions, gasoline for automobile, kerosene for domestic uses, and gas oil for diesel fuel uses according to its perfect property.  the deasphalted oil (dao) also used for production light fuel fractions, due to its heavy product, by thermal cracking operation unit.  coking, in particular, is recognized not only reduction in heavy fuel oil produced but also as a method of producing additional light products and distillates matter.  the severity of the process depends on the temperature and the residence time, to eliminate almost all lights matter from industrial petroleum coke. references [1] d. wang, l. jin, y. li. hu. upgrading of heavy oil with chemical looping partial oxidation. energy fuel, 2019, pp. 256 – 270. [2] m. ghashghaee, s. shirvani, s. kegnaes . steam catalytic cracking of fuel oil over a novel composite nano catalyst. j. anal. appl. pyrol. 138, 2019, pp. 280 294. [3] m. s. lopes. savioli lopes. cracking of petroleum residues by reactive molecular distillation. procedia engineering. 42, 2012, pp. 32934. [4] d. w. kim, p. r. jon, s. moon, c. h. lee. upgrading of petroleum vacuum residue using a hydrogen donor solvent with acid – treated carbon, energ. convers. manage, 161 (2018) pp. 230 – 244. [5] d. i. shishkova. effect of feed stock properties on conversion and yields; oil gaseuropean magazine 43 (2):84-89, 2017. [6] j. g speight. handbook of petroleum refining. crc press 2016. [7] s. parkash. petroleum fuels manufacturing hand book. the mc graw –hill, 2016 [8] j. g speight. fouling in refineries. gulf professional publishing, 2015. [9] g speight. hand book of petroleum product analysis .john wiley & sons, usa, 2015. [10] j g speight. the chemistry and technology of petroleum. crc press, 2014. [11] [g. charles hill. introduction to chemical engineering kinetic & reactor design. new york; john willy, 2014. [12] a. h. a.k mohammed and s. mohammed obeyed, “treatment of slack wax by thermal cracking process”, ijcpe, vol. 15, no. 3, pp. 1-7, sep. 2014. [13] e. douglas; j g. speight. refining used lubricating oils. crc press, 2014. [14] alkilani. a. haitham, m. s. taher a. al-sahhaf. fundamentals of petroleum refining ;first edition. elsevier 2010. [15] ebrahimi, s, j s moghaddas. study on thermal cracking behavior of petroleum residue. fuel 87 (89):1623-27, 2008. [16] lz pillion l. z. interfacial properties of petroleum products. crc press, 2007. [17] syamsuddin, y, b, a r mohammed . "thermal and catalytic cracking of petroleum residue oil." eng. j. univ. qatar 18 (2005): 1-8. [18] b k haskara rao. . modern petroleum refining processes. 4th ed., indian institute of technology, 2004. [19] jh gary, ge handwerk, and mj kaiser. petroleum refining: technology and economics. crc press, 2007. https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.8b03560 https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.8b03560 https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.8b03560 https://www.sciencedirect.com/science/article/abs/pii/s0165237018310167 https://www.sciencedirect.com/science/article/abs/pii/s0165237018310167 https://www.sciencedirect.com/science/article/abs/pii/s0165237018310167 https://www.sciencedirect.com/science/article/abs/pii/s0165237018310167 https://www.sciencedirect.com/science/article/pii/s187770581202824x https://www.sciencedirect.com/science/article/pii/s187770581202824x https://www.sciencedirect.com/science/article/pii/s187770581202824x https://www.sciencedirect.com/science/article/abs/pii/s0196890418301018 https://www.sciencedirect.com/science/article/abs/pii/s0196890418301018 https://www.sciencedirect.com/science/article/abs/pii/s0196890418301018 https://www.sciencedirect.com/science/article/abs/pii/s0196890418301018 https://www.researchgate.net/profile/dicho_stratiev2/publication/319095410_fluid_catalytic_cracking_and_thermal_cracking_of_vacuum_gas_oils_-_effect_of_feedstock_properties_on_conversion_and_yields/links/59d4cb50a6fdcc181adc5734/fluid-catalytic-cracking-and-thermal-cracking-of-vacuum-gas-oils-effect-of-feedstock-properties-on-conversion-and-yields.pdf https://www.researchgate.net/profile/dicho_stratiev2/publication/319095410_fluid_catalytic_cracking_and_thermal_cracking_of_vacuum_gas_oils_-_effect_of_feedstock_properties_on_conversion_and_yields/links/59d4cb50a6fdcc181adc5734/fluid-catalytic-cracking-and-thermal-cracking-of-vacuum-gas-oils-effect-of-feedstock-properties-on-conversion-and-yields.pdf 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https://www.wiley.com/en-km/introduction+to+chemical+engineering+kinetics+and+reactor+design,+2nd+edition-p-9781118368251 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/280 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/280 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/280 https://books.google.iq/books?hl=en&lr=&id=cawyawaaqbaj&oi=fnd&pg=pp1&dq=%5b13%5d%09e.+douglas%3b+j+g.+speight.+refining+used+lubricating+oils.+crc+press,+2014.&ots=qclxjvt3hm&sig=5t3xqkjhqwnclwgol7pnd2pwjum&redir_esc=y#v=onepage&q=%5b13%5d%09e.%20douglas%3b%20j%20g.%20speight.%20refining%20used%20lubricating%20oils.%20crc%20press%2c%202014.&f=false 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https://books.google.iq/books?hl=en&lr=&id=ocblbqaaqbaj&oi=fnd&pg=pp1&dq=%5b19%5d%09j.+h.+gary,+handwork,+g.+h+.+petroleum+refining+technology+and+economics.+4th+ed.+new+york.++marcel+dekker,+2001.&ots=alfvmu_2_a&sig=fkgkjq_2rmfdalfw0z7i1kio7dg&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=ocblbqaaqbaj&oi=fnd&pg=pp1&dq=%5b19%5d%09j.+h.+gary,+handwork,+g.+h+.+petroleum+refining+technology+and+economics.+4th+ed.+new+york.++marcel+dekker,+2001.&ots=alfvmu_2_a&sig=fkgkjq_2rmfdalfw0z7i1kio7dg&redir_esc=y#v=onepage&q&f=false s. m. obyed et al. / iraqi journal of chemical and petroleum engineering 21,3 (2020) 45 49 49 الحراري على المتبقي الفراغي سلوك التكسير دراسة سليم محمد عبيد, محمد سعدي حميد و عبدالكريم دهش عفات قسم الهندسة الكيمياوية-كلية الهندسة-جامعة النهرين الخالصة تعتبر عملية معالجة المتقطر الفراغي عملية مهمة جدا صناعيا النها ذات فائدة اقتصادية وبيئية ,الغرض من كناتج (زالصناعي ومقاطع وقود خفيفة )كازولين, كيروسين وزيت الغاانتاج الكوك البترولي ل هوهذا العم من معالجة مادة ثانوية وهي متبقي التقطير الفراغي الناتج ثانويرئيسيي والزيت الخالي من االسفلتينات كناتج تكسير الحراري )ال تاثير التحول الحراري بيانهذا العمل عمليا يهدفمن اسفل برج التقطير الفراغي للنفط الخام. داخل ( جو وزمن مكوث20وضغط )° م 500( عند درجة حرارة تصل الىكمادة اولية على )المتبقي الفراغي ( ذو دفعات للمعاملة الحرارية ساعة .الخطوة االولى للمعالجة كانت تصميم وتصنيع مفاعل 3 مفاعل التكسير وملحق به مجموعة من االجزاء المساعدة للسيطرة على مصنوع من الكاربون ستيل لترمل 700حجمه بحدود )الكازولين ف التفاعل ومربوط على التوالي مع وحدة التقطير الجوي وذلك لتقطير المواد الخفيفة المتطايرةو ظر وضغط ° م 350وفصلها عن الكوك البترولي الصناعي ولغاية درجة حرارة تصل الى ,الكيروسين ,الكازاويل( % حجم 4%حجم الكازولين الخفيف, 2الخفيفة كاالتي: البترولية وكان حجم المتقطر من المقاطعجوي واحد. من الثقيل % حجم الديزل. الخطوة الثانية هي معالجة المتبقي 24و % حجم الكيروسين 17الكازولين الثقيل , عن ي باالسفلت والمخلفاتالغن للمقطر الفراغي لغرض فصل مادة الكوك البترولي الصناعي الخطوة االولى حيث يتم اذابة الزيت السائل وذلك باستعمال مذيب بارافيني خفيف )البروبان( (dao)الزيت منزوع االسفلتين % من حجم اللقيم تاركا 15, حيث كان حجم هذا الزيت المفصول عن االسفلتين وفصله عن مادة االسفلت التركيبية مكوناتالمترسبة في المفاعل. وهذه هي المختلفة كالكبريت والمعادناالسفلتينات والمواد الثقيلة االخرى للتخلص من المواد °م 1100 – 1000 تصل الى يقسى الى درجة حرارةو يفصل الذي النفطي لكوك البتروليل اصفات الالزم توفرها في المو التجاريةواعطاء المواصفات في الكوك الصناعي المتطايرة الخفيفة الباقية البترولي. الصناعي النتاج الكوك المختبرية متقطر فراغي, تكسير, تكويك, تقطير :الكلمات الدالة available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol. 24 no.2 (june 2023) 71 – 79 eissn: 2618-0707, pissn: 1997-4884 *corresponding author: name: bashaer mahmoud namoos, email: bashaermahmood86@gmail.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. the effects of operating variables on efficancy of water disinfection by sodium hypochlorite using al-wathba wastewater bashaer mahmoud namoos a, *, majid i. abdul-wahab a, and wameath s. abdulmajeed b a chemical engineering department, college of engineering, university of baghdad, baghdad, iraq b chemical and petrochemical engineering department, university of nizwa, pc 616, pob 33, sultanate of oman abstract the aim of this investigation was to study the impact of various reaction parameters on wastewater taken from al-wathba water treatment plant on tigris river in south of baghdad, iraq with sodium hypochlorite solution. the parameters studied were sodium hypochlorite dose, contact time, initial fecal coliform bacteria concentration, temperature, and ph. in a batch reactor, different concentrations of sodium hypochlorite solution were used to disinfect 1l of water. the amount of hypochlorite ions in disinfected water was measured using an iodimetry test for different reaction times, whereas the most probable number (mpn) test was used to determine the concentration of coliform bacteria. total plate count (tpc) was utilized in this study to count the number of colonies of common bacteria. reaction variables that were examined showed that the increase in temperature, ph, and reaction time caused the concentration of coliform bacteria to decrease, which in turn caused an accumulation-related increase in oclconcentration. the optimum values of temperature and reaction ph were determined to be 8 and 29o c respectively. the kinetics of the reaction was examined in this study, and the results showed that selleck model's order of reaction is two, with rate constants of 1.3791x10-5, 3.0806x10-5, and 5.738x10-5 l/(mole min) at 20o, 29o, and 37o c, respectively. keywords: water disinfection, sodium hypochlorite, most probable number test, selleck model. received on 09/09/2022, received in revised form on 18/12/2022, accepted on 20/12/2022, published on 30/06/2023 https://doi.org/10.31699/ijcpe.2023.2.8 1introduction disinfection process is necessary for get rid of microorganisms that still in the treated water [1, 2]. several kinds of chemical substances have been used as disinfectants, such as; chlorine gas (cl2), chloride dioxide (clo2), ozone (o3), chloramines (nh2cl), calcium hypochlorite (ca(ocl)2), lithium hypochlorite (liocl), and sodium hypochlorite (naocl) [3]. typically, disinfectants are added at the last stage in water treatment plants. keeping a trace suspended for secondary disinfection in the distribution system to stop any microbial regrowth should be considered when determining the appropriate amount of disinfectants to kill all the organisms in water [4, 5]. however, it must be remembered that the process of disinfecting water also exposes consumers to some health risks due to some unfavorable side reactions occur in water [6]. this is demonstrated in the work of zazouli et al. [7], in which they show how these reactions can result in the production of disinfection by-products (dbps) from the natural organic materials (noms) that are already present in the water [8]. the carcinogenic effects of dbps on humans many researchers [9 13] who proved the relation between dbps and some cancers and renal failure. chlorine element is available in nature as combined-ion with calcium, magnesium, potassium, and sodium [14]. chlorine is considered as one of the most popular water disinfectants due to its relatively low cost, high disinfection-activity, and perfect oxidation potential [15]. on the other hand, using chlorine gas has the drawback of having low reaction selectivity, which results in undesirable byproducts. chlorine gas can rapidly oxidize noms producing dbps in water [16]. free chlorine concentrations in drinking water typically range from 0.2 to 2.0 mg/l, although they can reach 5.0 mg/l for restoring a water distribution system that is in need of repair or for treating water that has a high level of biological contamination [17]. the fact that chlorine is a poisonous gas that can cause death if it is concentrated enough must be mentioned. the chlorine gas water disinfection process is demonstrated in the reactions below [18]: cl2 + 𝐻2o → hocl + hcl (1) http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:bashaermahmood86@gmail.com http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2023.2.8 b. m. namoos et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 71 79 72 hocl ↔ h+ + ocl− (2) the decay of cl2 is controlled by the equilibrium between hocl and ocl-. acidity (ph) value plays an important role in effecting the equilibrium process acquiring [19]. the disinfection-activity of chlorine is reduced with the raising in ph value and the amount of the unassembled hypochlorous acid [18]. naocl was used in water disinfection field due to its proven germicides control, capability to combat a wide spectrum of microorganisms, nonpoisonous, nontoxic byproducts, easiness to handle, and low cost. naocl solution for domestic use is mostly between 1% to 5% in dilution of 1% to 15% stock [18]. since naocl is a clear liquid, it can be injected into the reactors as a solution; however, naocl has a stability issue that causes its concentration to decrease over time when exposed to sunlight [20, 21]. when sodium hypochlorite dilute in a pure water, chemical reaction occurs as it shown in eqs. 3 and 4, knowing that ph controls the amount of hocl and the oclion produced from the hocl decaying [22]. low ph shifts the naocl reaction towards producing hocl [23]. producing oclis assisted by the use of naocl to disinfect drinking water. according to bolyard et al. [24], naocl industrialization and storage can result in the production of ocl-. it is understood that oclcan generate clo3 =, as shown in eq. 5 below [25]: 𝑁𝑎𝑂𝐶𝑙 + 𝐻2o → naoh + hocl (3) hocl ↔ h+ + ocl− (4) 3 ocl− → 2 cl− + 3 clo= (5) corrosion is another issue that coexists with dbps problem that is caused by high chlorine concentrations in drinking water disinfection. corrosion takes place in the pipeline network that transports drinking water from projects to homes [26]. the corroded nature of chlorine acid and chlorite with metals, results in placement and distortion of its surface and from then stripping the layers of metal in a cumulative effect over time [27]. this causes an additional infection to the drinking water, which needs an increase in the amount of free remaining chlorine in water for the secondary disinfection process. this will also lead to an additional increasing in the erosion problem and the amount of dbps together [28]. in order to avoid any interaction of secondary reactions brought on by the corrosive nature of the naocl, which could affect the accuracy of the results, glass beakers, tubes, and bottles were used in this work. coliform bacteria can enter to the human body through consuming infected food and drinks [29]. due to the fact that coliform bacteria are among the organisms that can contaminate wastewater, as well as their affordability and ease of use in water analysis, coliform bacteria have come to be used as a quality standard for water disinfection processes [30]. coliform consume glucose and convert it to acetic acid, d-lactate, l-lactate, and ethanol for energy [31]. this work was aimed to study the different variables that can affect the water disinfection quality and also the reaction kinetics for sodium hypochlorite as a water disinfectant, using e coli bacteria in wastewater, through selleck method instead of harriet methods as other works did. this work focused on the interaction that takes place between the effect of concentration of e coli bacteria in a particular way with the influence of oclconcentration during the course of the reaction process by examining the effect of changing ph, temperature, and initial concentrations of bacteria and sodium hypochlorite. the possibility of accelerating water disinfection processes by raising the temperature of the treated water, especially in projects that aim to treat and disinfect small amounts of water, can be realized by studying the reaction mechanism of the chlorination wastewater process and calculating the rate constants for different temperatures. for large wastewater treatment plants, the process can be accelerated in summer since the water naturally originates from warm sources. this lowers the cost of energy consumption and increases process efficiency by shortening the duration of the water chlorination process. 2experimental work from the general diagram in fig. 1, a sequence of the experimental work steps can be observed. 2.1. chemical materials sodium hypochlorite (naocl) (97% across organics), lauryl tryptose broth (ltb) (99% merck), starch (98% sigma-aldrich), potassium iodide (ki) (99% sigmaaldrich) 2.2. samples collection wastewater samples were brought from alwathba water treatment plant. samples were rounded by ice to suppress the bacterial activity and transported next day to the laboratory. 2.3. wastewater disinfection reaction naocl solution was used to disinfect treated water. the variables studied were initial concentrations of fecal coliform bacteria, reaction temperature, reaction ph value, reaction time, and naocl solution doses. 1% naocl solution was used to treat 1l, of wastewater in a batch reactor, with various doses being injected each time. 2.4. biological and chemical tests samples were tested biologically (mpn. and tpc) and chemically (iodimetry) for various reaction times. mpn test been accomplished initially (t = 0 minute) for one set of five tubes with different dilutions (10-1, 10-2, 10-3). one ml of each dilution was injected into the l.t.b. media in each set, while 20 ml of the samples injected into the triple concentration l.t.b. media set for different reaction times. fig. 2 demonstrates how to distinguish between the contaminated and healthy l.t.b tubes for mpn test. on b. m. namoos et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 71 79 73 the other side, 25 ml of water sample was tested by titration with the starch for iodimetry test, ki was used as an indicator [32]. fig. 1. flowchart diagram, illustrating the steps in the experiment's wastewater disinfection by sodium hypochlorite fig. 2. mpn tubes test, (a) positive ltb tube, (b) negative ltb tube 2.5. incubation process the initial mpn tubes (contact time = 0) test and petri dish for the t.p.c test incubated in a memmert incubator for two days at 37oc, while the sets of mpn test for 5, 15, 30, 60, 90, and 120 minutes of reaction time incubated in the same incubator at 37oc for 24 hour [32]. 3results and discussion 3.1. most probable number and iodimetry tests the most probable number (mpn) method is used to determine the concentration of viable microorganisms in a sample by replicating liquid broth growth in ten-fold dilutions. it is frequently applied to the estimation of microbial populations in agricultural products, waters, and soils [33]. when samples contain particulate matter that obstructs plate count enumeration techniques, mpn tests are particularly helpful. in order to determine whether the water is safe to drink in terms of the amount of bacteria present, mpn is most frequently used to test the quality of water [34]. fecal contamination of water is indicated by a class of bacteria known as fecal coliforms [35]. in contrast, the presence of large numbers of fecal coliform bacteria would indicate a very high probability that the water could contain disease-producing microorganisms making the water unsafe for consumption. the presence of very few fecal coliform bacteria would indicate that water probably contains no disease-causing microorganisms [36]. while iodimetry test is a technique for volumetric chemical analysis that uses a redox titration to determine the point at which elementary iodide appears or vanishes, this absorption will cause the solution's color to change from deep blue to light yellow, estimating active chlorine ion concentration. 3.1.1 effects of initial coliform bacteria concentration the impact of the initial bacterial concentration of fecal coliform bacteria on the process of water disinfection was examined using two concentrations (1300 and 2200 coliform/l). for various bacterially contaminated samples, the decaying in fecal coliform bacteria is shown in fig. 3a and fig. 3b, by comparing the results of 2200 coliform bacteria at a constant ph of 7.5 with the results of 1300 coliform bacteria. it can be seen that the decay exhibits a decrease in the number of coliform bacteria to its initial number (n/no). based on the decrease in this ratio, it can be indicated that the order of the reaction between naocl and water is higher than one, and this is going in agreement with asami et al.’s [37] opinion. others like lister [38] stated that the order of this reaction was near two. fig. 4a shows that for the 2200 coliform/l, the amount of oclproduced by the decomposition of naocl in water is consumed less by the coliform bacteria compared to the concentration of 1300 coliform/l. this is demonstrated by that the amount of oclwhich increased after 60 minutes for the dosage of 20 ppm nocl in fig. 4b. this is associated with the complete consumption of the coliform bacteria at 20 ppm b. m. namoos et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 71 79 74 shown in fig. 3b. without the coliform bacteria present in the water, the hypochlorite ion produced by the decay of naocl will continue to accumulate in the water, increasing its concentration. fig. 3. concentration of coliform bacteria with reaction time at ph = 7.5 and temperature = 29o c, (a) no = 2200 coliform/l and tpc =98 colonies, (b) no = 1300 coliform/l and tpc = 51 colonies fig. 4. concentration of oclwith reaction time for ph = 7.5, and temperature = 29o c, (a) no = 2200 coliform/l and tpc =98 colonies, (b) no = 1300 coliform/l and tpc = 51 colonies 3.1.2. effect of ph values effects of three different ph values (6.5, 7.5, and 8) were examined on the effectiveness of water disinfection by naocl, fig. 5a and fig. 5b. it is shown that the increase in ph values caused a reduction in the concentration of coliform bacteria. this is in line with the finding of mcfadden et al. [39]. the ph values were reduced from the ideal ph at 7.5 (fig. 3b) to 6.5 (fig. 5a), increasing the amount of bacteria capacity for feeding, which provides a suitable environment for bacteria to multiply, and this can be seen through the increase in the lactic acid and acetic acid that produced as a result of bacteria’s feeding. it is shown also that the rise in sodium hypochlorite solution caused drop in coliform bacteria concentration, concentration of hypochlorous acid and hypochlorite ions, which are responsible of destroying germs during the disinfection process which is inconsistent with cotter et al. [40]. increasing ph values leads to an increase in ocl concentration, as shown in fig. 6. although the effect of the accumulation of oclis more effective in the results even when the alkaline environment reduces the decaying capacity of naocl, this fact causes the impact and momentum into the accumulated amount of oclto be reduced at high ph values, yet not preventing it. this resulted in a higher oclconcentration at ph 8 as shown in fig. 6b comparing with ph 6.5 and 7.5 (fig. 6a, and fig. 4b), which sharply reduced the number of coliform bacteria (fig. 5b). this will reduce the need for hocl consumption during the pathogens' killing process and caused oclto accumulate in the disinfected water, as shown in the eq. 4. fig. 5. concentration of coliform bacteria with reaction time at no = 1300, tpc = 51 colonies, and temperature = 29o c, (a) ph = 6.5, (b) ph = 8 b. m. namoos et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 71 79 75 fig. 6. concentration of oclwith reaction time for no = 1300 coliform/l, tpc = 51 colonies, and temperature = 29o c, (a) ph = 6.5, (b) ph = 8 3.1.3. effect of temperature different reaction temperatures; 20, 29, and 37 oc were tested in this work. it was noticed that when the temperature of reaction is increased, coliform bacteria amount is reduced, this is due to the increasing in the rate of reaction [42], fig. 7a, fig. 3b and fig. 7b. the naocl disinfection reaction's second order nature can be demonstrated by the opposite relationship between temperature and the availability of coliform bacteria's residuals. because the rate of reaction has increased due to the rise in reaction temperature, as shown in fig. 8a and fig. 8b, the amount of oclat 5 minutes of contact with the naocl in the reactor at 20° c is less than the amount at 29° c. this agrees with adams' finding [26], who had noted that increasing the reaction temperature could actually accelerate sodium hypochlorite's conversion to hypochlorous acid and hypochlorite ions. 3.2. reaction kinetics kinetics of naocl disinfection was studied in this work. different kinetic models have been tested. harriet chick model was tried to fit the reaction data for the ph = 7.5 and 29o c reaction with the 1300 initial coliform concentration in one litter of treated water [43]. the model was tested for first and second reaction order for the same naocl disinfection reaction data as shown in fig. 9a and fig. 9b. fig. 7. concentration of coliform bacteria with reaction time at no = 1300, tpc = 51 colonies, and ph= 7.5, (a) temperature = 20o c, (b) temperature = 37o c fig. 8. concentration of oclwith reaction time for no = 1300 coliform/l, tpc = 51 colonies, and ph= 7.5, (a) temperature = 20o c, (b) temperature = 37o c b. m. namoos et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 71 79 76 fig. 9. harriet chick for the ratio of remaining coliform bacteria after different reaction time, (a) first order, (b) second order the 2nd order equation is: 1 [ocl] − 1 [ocl]0 = k x t (6) it is clear that the data of the naocl disinfection reaction cannot be fit by the first order and second order reaction of the harriet chick model. wu et al. [44] showed the same conclusion in their study. the general power low (eq. 7) has been tested in this work by using visual basic computer program with 0.1% error. the fluctuating in degree and rate of reaction led to indicate this model as an unsuitable for the naocl disinfection reaction [43]. –rn = -dn/dt = k n n (7) at 1978 selleck described the effect of chlorine on coliform bacteria in wastewater by design a model (eq. 8) that counting on the bacteria and hypochlorite ion. this makes selleck model suitable to be applied to the data of our work. log ( n n0 ) = −n log ( 1 + [ocl] x t 𝐾 ) (8) selleck model succeeded to calculate the reaction kinetics for water disinfection by naocl by using visual basic with an 9% error, selleck model estimated that the degree of reaction for water disinfection by naocl is second order (fig. 10). the rate of reactions obtained are listed in table 1. table 1. the rate of reactions temperature (o c) rate of reaction (l *(mole min)-1) 20 1.3791 x 10-5 29 3.0806 x 10-5 37 5.738 x 10-5 fig. 10. selleck model second order for the ratio of remaining coliform bacteria after different reaction time 4conclusion the present work demonstrated that naocl is very effective as a disinfectant in the drinking water field, in which five minutes was sufficient to kill the majority of coliform bacteria. the study also proved that the ph value of the reaction has a great effect on suppressing the pathogens growing and increase the killing of coliform bacteria. using ph value of 8 raised the disinfection process activity by killing most of the coliform bacteria with less amount of naocl and reduced the dbps produced as side reactions of the disinfection process by chlorine. temperature also has an important effect on the rate of reaction in addition to the coliform bacteria concentration. the rate of reaction increases with the increase in the initial bacteria concentration and temperature. the kinetics of the disinfection reaction was well represented by selleck model in which the order of the disinfection reaction was found to be two. acknowledgment the authors wish to thank the head and the staff of al wathba water treatment plant laboratory and the department of biology of baghdad university for their help and support during the course of research. references [1] h. e. al-hazmi et al., “recent advances in aqueous virus removal technologies,” chemosphere, vol. 305, p. 135441, 2022, https://doi.org/10.1016/j.chemosphere.2022.135441 [2] m. h. salih and a. f. al-alawy, “crystallization process as a final part of zero liquid discharge systemfor treatment of east baghdad oilfield produced water,” desalin. iraqi j. chem. pet. eng., vol. 23, pp. 15–22, 2022, https://doi.org/10.31699/ijcpe.2022.1.3 https://doi.org/10.1016/j.chemosphere.2022.135441 https://doi.org/10.31699/ijcpe.2022.1.3 b. m. namoos et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 71 79 77 [3] a.m. k. pandian, m. rajamehala, m. v. p. singh, g. sarojini, and n. rajamohan, “potential risks and approaches to reduce the toxicity of disinfection byproduct a review,” sci. total environ., vol. 822, p. 153323, 2022, https://doi.org/10.1016/j.scitotenv.2022.153323 [4] m. bartolomeu et al., “photodynamic inactivation of microorganisms in different water matrices: the effect of physicochemical parameters on the treatment outcome sci. total environ., p. 160427, 2022, https://doi.org/10.1016/j.scitotenv.2022.160427 [5] a. f. al-alalawy, t. r. abbas, and h. k. mohammed, “osmostic membrane bioreactor for oily wastewater treatment using external & internal configurations,” iraqi j. chem. pet. eng., vol. 17, pp. 71–82, 2016. [6] s. tsitsifli and v. kanakoudis, “disinfection impacts to drinking water safety a review,” proceedings, vol. 2, pp. 1–7, 2018. https://doi.org/10.3390/proceedings2110603 [7] m. a. zazouli and l. r. kalankesh, “removal of precursors and disinfection byproducts (dbps) by membrane filtration from water; a review,” journal of environmental health science & engineering, vol. 15 pp. 1–10, 2017. https://doi.org/10.1186/s40201017-0285-z [8] l. e. anderson et al., “a review of long-term change in surface water natural organic matter concentration in the northern hemisphere and the implications for drinking water treatment,” sci. total environ., vol. 858, p. 159699, 2023, https://doi.org/10.1016/j.scitotenv.2022.159699 [9] a. seretis et al., “association between blood pressure and risk of cancer development: a systematic review and meta-analysis of observational studies,” sci. rep., vol. 9, pp. 1–12, 2019. https://doi.org/10.1038/s41598-019-45014-4 [10] p. sicińska, e. jabłońska, b. bukowska, a. balcerczyk, and e. reszka, “the selected epigenetic effects of phthalates: dbp, bbp and their metabolites: mbp, mbzp on human peripheral blood mononuclear cells (in vitro),” toxicol. vitr., vol. 82, 2022, https://doi.org/10.1016/j.tiv.2022.105369 [11] j. wang et al., “immune dysfunction induced by 2,6dichloro-1,4-benzoquinone, an emerging water disinfection byproduct, due to the defects of hostmicrobiome interactions,” chemosphere, vol. 294, p. 133777, 2022. https://doi.org/10.1016/j.chemosphere.2022.133777 [12] z. pang et al., “occurrence and modeling of disinfection byproducts in distributed water of a megacity in china: implications for human health,” sci. total environ., vol. 848, p. 157674, 2022. https://doi.org/10.1016/j.scitotenv.2022.157674 [13] b. shao et al., “disinfection byproducts formation from emerging organic micropollutants during chlorine-based disinfection processes,” chem. eng. j., p. 140476, 2022. https://doi.org/10.1016/j.cej.2022.140476 [14] y. wang et al., “hydrogen generation from photocatalytic treatment of wastewater containing pharmaceuticals and personal care products by oxygen-doped crystalline carbon nitride,” sep. purif. technol., vol. 296, p. 121425, 2022, https://doi.org/10.1016/j.seppur.2022.121425 [15] b. omran and k. h. baek, “graphene-derived antibacterial nanocomposites for water disinfection: current and future perspectives,” environ. pollut., vol. 298, p. 118836, 2022, https://doi.org/10.1016/j.envpol.2022.118836 [16] e. e. lavonen, m. gonsior, l. j. tranvik, p. schmittkopplin, and s. j. ko, “selective chlorination of natural organic matter: identi fi cation of previously unknown disinfection byproducts,” environ. sci. technol., vol., 47, pp. 2264−2271, 2013. https://doi.org/10.1021/es304669p [17] z. wang, y. liao, x. li, c. shuang, y. pan, y. li, a. li, “effect of ammonia on acute toxicity and disinfection byproducts formation during chlorination of secondary wastewater effluents,” sci. total environ., vol. 826, pp. 153916, 2022. https://doi.org/10.1016/j.scitotenv.2022.153916 [18] m. c. collivignarelli, “overview of the main disinfection processes for wastewater and drinking water treatment plants,” sustainability, vol. 10, pp. 1–21., 2018. https://doi.org/10.3390/su10010086 [19] r. wei, h. tong, j. zhang, b. sun, and s. you, “flow electrochemical inactivation of waterborne bacterial endospores,” j. hazard. mater., vol. 445, p. 130505, 2023. https://doi.org/10.1016/j.jhazmat.2022.130505 [20] world health organization. water, sanitation and health team, who guidelines for drinking water quality: training pack. world health organization., 2000. [21] h. zhang, l. zhao, d. liu, j. wang, x. zhang, and c. chen, “early period corrosion and scaling characteristics of ductile iron pipe for ground water supply with sodium hypochlorite disinfection,” water res., vol. 176, pp. 115742, 2020. https://doi.org/10.1016/j.watres.2020.115742 [22] s. jiang, y. liu, h. qiu, c. su, and z. shao, “high selectivity electrocatalysts for oxygen evolution reaction and anti-chlorine corrosion strategies in seawater splitting,” catalysts, vol. 12, pp. 1–17, 2022. https://doi.org/10.3390/catal12030261 [23] w. a. mitch, “influence of the order of reagent addition on ndma formation during chloramination,” environ. sci. technol., vol. 39, pp. 3811-3818, 2005. https://doi.org/10.1021/es0483286 [24] m. bolyard, p. s. fair, d. p. hautman, “sources of chlorate ion in us drinking water,” awwa, vol. 85, pp. 81–88, 1993. https://doi.org/10.1002/j.15518833.1993.tb06064.x [25] y. choi, s. h. byun, h. j. jang, s. e. kim, and y. choi, “comparison of disinfectants for drinking water: chlorine gas vs. on-site generated chlorine,” environ. eng. res., vol. 27, pp. 200543–0, 2021. https://doi.org/10.4491/eer.2020.543 https://doi.org/10.1016/j.scitotenv.2022.153323 https://doi.org/10.1016/j.scitotenv.2022.160427 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/234 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/234 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/234 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/234 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/234 https://doi.org/10.3390/proceedings2110603 https://doi.org/10.1186/s40201-017-0285-z https://doi.org/10.1186/s40201-017-0285-z https://doi.org/10.1016/j.scitotenv.2022.159699 https://doi.org/10.1038/s41598-019-45014-4 https://doi.org/10.1016/j.tiv.2022.105369 https://doi.org/10.1016/j.chemosphere.2022.133777 https://doi.org/10.1016/j.scitotenv.2022.157674 https://doi.org/10.1016/j.cej.2022.140476 https://doi.org/10.1016/j.seppur.2022.121425 https://doi.org/10.1016/j.envpol.2022.118836 https://doi.org/10.1021/es304669p https://doi.org/10.1016/j.scitotenv.2022.153916 https://doi.org/10.3390/su10010086 https://doi.org/10.1016/j.jhazmat.2022.130505 https://apps.who.int/iris/bitstream/handle/10665/66218/a68673.pdf https://apps.who.int/iris/bitstream/handle/10665/66218/a68673.pdf https://apps.who.int/iris/bitstream/handle/10665/66218/a68673.pdf https://apps.who.int/iris/bitstream/handle/10665/66218/a68673.pdf https://doi.org/10.1016/j.watres.2020.115742 https://doi.org/10.3390/catal12030261 https://doi.org/10.1021/es0483286 https://doi.org/10.1002/j.1551-8833.1993.tb06064.x https://doi.org/10.1002/j.1551-8833.1993.tb06064.x https://doi.org/10.4491/eer.2020.543 b. m. namoos et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 71 79 78 [26] s. zhang, y. tian, h. guo, r. liu, n. he, z. li, w. zhao, “study on the occurrence of typical heavy metals in drinking water and corrosion scales in a large community in northern china,” chemosphere, vol. 290, pp. 133145, 2022. https://doi.org/10.1016/j.chemosphere.2021.133145 [27] f. borgioli, “from austenitic stainless steel to expanded austenite-s phase: formation, characteristics and properties of an elusive metastable phase,” metals (basel)., vol. 10, pp. 1–46, 2020, https://doi.org/10.3390/met10020187 [28] x. song et al., “visible light-driven chlorite activation process for enhanced sulfamethoxazole antibiotics degradation, antimicrobial resistance reduction and biotoxicity elimination,” chem. eng. j., vol. 452, p. 139103, 2023, https://doi.org/10.1016/j.cej.2022.139103 [29] t. küpper et al., “analysis of local drinking water for fecal contamination in solu-khumbu / mt. everest region, nepal,” int. j. hyg. environ. health, vol. 246, p. 114043, 2022, https://doi.org/10.1016/j.ijheh.2022.114043 [30] j. lin and a. ganesh, “water quality indicators: bacteria, coliphages, enteric viruses,” international journal of environmental health research, vol. 23, pp. 484–506, 2013. https://doi.org/10.1080/09603123.2013.769201 [31] abdul-wahab, m. i., & namoos, b. m. (2018). kinetic of disinfection reaction by sodium hypochlorite solution. iraqi journal of chemical and petroleum engineering, 19(1), 51–56. [32] j. bartram and s. pedley, “water quality monitoring a practical guide to the design and implementation of freshwater quality quality studies and monitoring programmes, chapter 10 microbilogical analyses,” unep/who, 1996. [33] waheeb h. a. and al-alalawy a. f., “innovative microbial fuel cell design for investigation of cathode chamber effect and electricity generation enhancement”, aip conference proceedings 2213, 020212, 2020. https://doi.org/10.1063/5.0000172 [34] z. wang, g. xiao, n. zhou, w. qi, l. han, and y. ruan, “comparison of two methods for detection of fecal indicator bacteria used in water quality monitoring of the three gorges reservoir,” jes, vol. 38, pp. 42–51, 2015. https://doi.org/10.1016/j.jes.2015.04.029 [35] s. some, r. mondal, d. mitra, d. jain, d. verma, and s. das, “microbial pollution of water with special reference to coliform bacteria and their nexus with environment,” energy nexus, vol. 1, pp. 100008, 2021. https://doi.org/10.1016/j.nexus.2021.100008 [36] m. b. aregu, g. g. kanno, z. ashuro, a. alembo, and a. alemayehu, “safe water supply challenges for hand hygiene in the prevention of covid-19 in southern nations, nationalities, and people’ s region (snnpr), ethiopia,” heliyon, vol. 7, p. e08430, 2021, https://doi.org/10.1016/j.heliyon.2021.e08430 [37] m. asami, k. kosaka, and s. kunikane, “bromate, chlorate, chlorite and perchlorate in sodium hypochlorite solution used in water supply,” journal of water supply: research and technology aqua, vol. 58.2, pp. 107–115, 2009. https://doi.org/10.2166/aqua.2009.014 [38] m. y. lister, “decomposition of sodium hypochlorite: the uncatalyzed reaction1,” canadian journal of chemistry, vol. 34, pp. 465–478, 1955. https://doi.org/10.1139/v56-068 [39] m. mcfadden, j. loconsole, a. j. schockling, r. nerenberg, and j. p. pavissich, “comparing peracetic acid and hypochlorite for disinfection of combined sewer overflows: effects of suspended-solids and ph,” sci. total environ., vol. 599–600, pp. 533–539, 2017. https://doi.org/10.1016/j.scitotenv.2017.04.179 [40] p. d. cotter and c. hill, “surviving the acid test: responses of gram-positive bacteria to low ph,” microbil. mol. biol. rev., vol. 67, pp. 429–453, 2003. https://doi.org/10.1128/mmbr.67.3.429453.2003 [41] r. changotra, a. k. ray, and q. he, “establishing a water-to-energy platform via dual-functional photocatalytic and photoelectrocatalytic systems: a comparative and perspective review,” adv. colloid interface sci., vol. 309, p. 102793, 2022, https://doi.org/10.1016/j.cis.2022.102793 [42] j. k. mwabi, b. b. mamba, and m. n. b. momba, “removal of escherichia coli and faecal coliforms from surface water and groundwater by household water treatment devices/systems: a sustainable solution for improving water quality in rural communities of the southern african development community regi,” int. j. environ. res. public health, vol. 9, pp. 139-170, 2012. https://doi.org/10.3390/ijerph9010139 [43] m. b.said, m. b. saad, f. achouri, l. bousselmi, a. ghrabi, “the application of phage reactivation capacity to sens bacterial viability and activity after photocatalytic treatment,” vol. 42, pp. 2836–2844, 2021. https://doi.org/10.1080/09593330.2020.1716078 [44] h. wu and c. c. dorea, “evaluation and application of chlorine decay models for humanitarian emergency water supply contexts,” environ. technol., vol. 43, pp. 3221-3230, 2021. https://doi.org/10.1080/09593330.2021.1920626 https://doi.org/10.1016/j.chemosphere.2021.133145 https://doi.org/10.3390/met10020187 https://doi.org/10.1016/j.cej.2022.139103 https://doi.org/10.1016/j.ijheh.2022.114043 https://doi.org/10.1080/09603123.2013.769201 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/225 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/225 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/225 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/225 https://books.google.iq/books?hl=en&lr=&id=wfijb1iovcic&oi=fnd&pg=pp13&dq=water+quality+monitoring+-+a+practical+guide+to+the+design+and+implementation+of+freshwater+quality+quality+studies+and+monitoring+programmes&ots=5pfplglgm3&sig=u4e-cehmqtsbnndihcoqw6pjkpa&redir_esc=y#v=onepage&q=water%20quality%20monitoring%20-%20a%20practical%20guide%20to%20the%20design%20and%20implementation%20of%20freshwater%20quality%20quality%20studies%20and%20monitoring%20programmes&f=false https://books.google.iq/books?hl=en&lr=&id=wfijb1iovcic&oi=fnd&pg=pp13&dq=water+quality+monitoring+-+a+practical+guide+to+the+design+and+implementation+of+freshwater+quality+quality+studies+and+monitoring+programmes&ots=5pfplglgm3&sig=u4e-cehmqtsbnndihcoqw6pjkpa&redir_esc=y#v=onepage&q=water%20quality%20monitoring%20-%20a%20practical%20guide%20to%20the%20design%20and%20implementation%20of%20freshwater%20quality%20quality%20studies%20and%20monitoring%20programmes&f=false https://books.google.iq/books?hl=en&lr=&id=wfijb1iovcic&oi=fnd&pg=pp13&dq=water+quality+monitoring+-+a+practical+guide+to+the+design+and+implementation+of+freshwater+quality+quality+studies+and+monitoring+programmes&ots=5pfplglgm3&sig=u4e-cehmqtsbnndihcoqw6pjkpa&redir_esc=y#v=onepage&q=water%20quality%20monitoring%20-%20a%20practical%20guide%20to%20the%20design%20and%20implementation%20of%20freshwater%20quality%20quality%20studies%20and%20monitoring%20programmes&f=false https://books.google.iq/books?hl=en&lr=&id=wfijb1iovcic&oi=fnd&pg=pp13&dq=water+quality+monitoring+-+a+practical+guide+to+the+design+and+implementation+of+freshwater+quality+quality+studies+and+monitoring+programmes&ots=5pfplglgm3&sig=u4e-cehmqtsbnndihcoqw6pjkpa&redir_esc=y#v=onepage&q=water%20quality%20monitoring%20-%20a%20practical%20guide%20to%20the%20design%20and%20implementation%20of%20freshwater%20quality%20quality%20studies%20and%20monitoring%20programmes&f=false https://books.google.iq/books?hl=en&lr=&id=wfijb1iovcic&oi=fnd&pg=pp13&dq=water+quality+monitoring+-+a+practical+guide+to+the+design+and+implementation+of+freshwater+quality+quality+studies+and+monitoring+programmes&ots=5pfplglgm3&sig=u4e-cehmqtsbnndihcoqw6pjkpa&redir_esc=y#v=onepage&q=water%20quality%20monitoring%20-%20a%20practical%20guide%20to%20the%20design%20and%20implementation%20of%20freshwater%20quality%20quality%20studies%20and%20monitoring%20programmes&f=false https://doi.org/10.1063/5.0000172 https://doi.org/10.1016/j.jes.2015.04.029 https://doi.org/10.1016/j.nexus.2021.100008 https://doi.org/10.1016/j.heliyon.2021.e08430 https://doi.org/10.2166/aqua.2009.014 https://doi.org/10.1139/v56-068 https://doi.org/10.1016/j.scitotenv.2017.04.179 https://doi.org/10.1128/mmbr.67.3.429-453.2003 https://doi.org/10.1128/mmbr.67.3.429-453.2003 https://doi.org/10.1016/j.cis.2022.102793 https://doi.org/10.3390/ijerph9010139 https://doi.org/10.1080/09593330.2020.1716078 https://doi.org/10.1080/09593330.2021.1920626 b. m. namoos et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 71 79 79 يوم لصودتأثير متغيرات التفاعل على كفاءة عملية تعقيم المياه بواسطة هايبوكلورايت ا الوثبهباستخدام المياه المعالجة في مشروع 2و وميض شوقي عبد المجيد ،1 ماجد أبراهيم عبد ألوهاب ،*، 1 بشائر محمود ناموس العراق ،بغداد ،جامعة بغداد ،كلية الهندسة ،قسم الهندسة الكيمياوية 1 سلطنة عمان ،جامعة نزوى ،ندسة الكيمياوية والبتروكيمياويةقسم اله 2 الخالصة من دراسة تأثير معامالت التفاعل المختلفة على مياه الصرف الصحي المأخوذةالهدف من هذا التحقيق هو : عراق بمحلول هيبوكلوريت الصوديوم، مثل، المياه على نهر دجلة في جنوب بغدادمحطة الوثبة لمعالجة ال وضة. الحم رجة، ودرجة الحرارة ودلبكتيريا القولونيةتفاعل، التركيز االولي لل، وقت اجرعة هيبوكلوريت الصوديوم وديوم. تم لتر من المياه بتراكيز مختلفه من الهايبوكلورايت الص 1تم استخدام المفاعل الدفعي في عملية تعقيم فحص وقياس ايونات الهايبوكلورايت في الماء المعقم باستخدام طريقه التسحيح االيودي في اوقات تفاعل يقة دمت طر احتماليه لقياس تراكيز البكتريا القولونية. استخ مختلفة، في حين تم استخدام طريقة االعداد االكثر . عقيمهاصحون االختبار لقياس العدد االجمالي للمستعمرات لالنواع المختلفة من البكتريا في المياه المزمع ت حموضةأظهرت متغيرات التفاعل المختلفة التي تم فحصها في هذا العمل أن الزيادة في درجة الحرارة ودرجة ال ن يز ايو ، مما أدى بدوره إلى زيادة تراكميه في تركلونيةوزمن التفاعل تسببت في تقليل تركيز البكتيريا القو لعمليهالهايبوكلورايت الناتج من التفاعل. في هذا العمل قد ضهر انه درجة الحراره ودرجة الحموضه المثلى ل نموذج راسة ميكانيكية التفاعل في هذا العمل انههرت دظاعلى التوالي. 8درجه سيليزيه و 29التفاعليه هي ت سيليك هو النموذج المثالي للتعبير عن درجة التفاعل وثابت سرعته، حيث قد ثبت ان تفاعل هايبوكلوراي 10x 3.0806-5و 10x 1.3791-5 بينقيم ثوابت سرعة تتراوح ب الصوديوم مع الماء هو من الدرجه الثانية، درجة سيليزية. 37و 29 ،20الدرجات الحرارية لتر/)مول*دقيقة( عند 10x 5.738-5و .، نموذج سيليكأختبار أالعداد أالكثر احتمالية ،هايبوكلورايت الصوديوم ،تعقيم المياة الكلمات الدالة: iraqi journal of chemical and petroleum engineering vol.13 no.2 (june 2012) 2936 issn: 1997-4884 effect of annealing on the crystallization of poly vinyl chloride for drug delivery system basma a. abdul-majeed, hussain k. hussain and nagam a. kafel al-sultanee chemical engineering department, college of engineering, university of baghdad abstract poly vinyl alcohol has been studied for its ability to form crystallites by using annealing method. semicrystalline films of poly vinyl alcohol (pva) were prepared by casting 11.5 wt. % and 13 wt. % pva aqueous solution onto glass slides at annealing temperature range 90 -120°c and duration time 1560 minute. this allowed the macromolecules to form crystallites, small regions of folded and compacted chains separated by amorphous regions where single pva chain may pass through several of these crystallites. degree of crystallinity of pva films (hydrogels) was determined by method of density; on the other hand the swelling behavior was conducted by the determination of water uptake, wet degree of crystallinity, gel fraction and solubility. the results of pva films showed that water uptake decreased with increasing temperature, time of annealing and pva concentration, while degree of crystallinity increased, and gel fraction and solubility decreased with increasing temperature and time of annealing. the maximum dry and wet degree of crystallinity was 64% and 36% respectively at 120°c and 60 min. key words: poly (vinyl alcohol)–annealing–swellingcrystallinity. introduction advances in polymer science have opened up possibilities for using a wide variety of polymeric materials as drug delivery systems. biodegradable polymers, by virtue of their ability to degrade in the body naturally, offer enormous advantages over conventional drug delivery systems [1,2]. it eliminated the need for surgery and also does not elicit any adverse reactions from the body. polymeric drug delivery systems are mainly intended to deliver the drug over a period of time. some of the materials that are currently being used/studied for controlled drug delivery include poly methyl methacrylate, poly vinyl alcohol, polyacrylamide, polyethylene glycol, polylactic acid, polyglycolic acid, polylacticglycolic acid, and polyanhydrides [3]. hydrogels of polymer are gaining increasing popularity in the area of controlledrelease drug delivery. these polymers are generally glassy in the dehydrated state but swell to become an elastic gel upon water penetration. the entrapped drug within the swelling matrix concomitantly dissolves and diffuses through the swollen network into surrounding aqueous environment. the rate of drug release from hydrogels is regulated by cross-linking density and the extent of swelling [4]. poly vinyl iraqi journal of chemical and petroleum engineering university of baghdad college of engineering effect of annealing on the crystallization of poly vinyl chloride for drug delivery system 30 ijcpe vol.13 no.2 (june 2012) -available online at: www.iasj.net alcohol (pva) is a hydrophilic polymer with unique properties. it absorbs water, swells easily and it has extensively been used in controlled release applications [5]. several methods have been explored to form semicrystalline pva for use in biomedical applications. one early method studied by peppas [6] explored crystallization by a slow dehydration process. peppas et al. [7] studied formation of crystallites by a freezethaw process. thin amorphous films of pva were frozen for 8 h at -20°c and then thawed for 4 h at 25°c. this cycle was repeated several times. they showed that as the number of freezethaw cycles increased the stability of the crystallites during swelling increased. however, the total number of crystals in the hydro gel did not necessarily increase with increased freeze-thaw cycles. they also added peg [8] to hydro gels formed by the freeze-thaw process, and showed that the resulting hydro gels exhibited increased stability during swelling. other studies have used a combination of cross-linking and crystallization techniques to probe the characteristics of pva hydro gels under various crystallization and swelling conditions. mallapragada and peppas [9] studied the effect of swelling on the crystalline regions of pva hydro gels. the pva networks were created by first crosslinking aqueous solutions of pva using electron-beam irradiation, followed by annealing to form crystallites. using ir spectroscopy to compare the crystallinity before and after swelling, they showed that the swelling process did not affect the crystallites in the semicrystalline pva; only the amorphous regions of the hydro gel were penetrated by the water molecules. another technique for crystallization of pva is annealing at a temperature between the glass transition temperature and the melting point; mallapragada et al. [10] conducted some of the earliest experiments using this annealing process. these studies also explored dissolution mechanisms of pva hydro gels that had been crystallized using annealing. unlike previous works, these annealed films were not previously cross-linked, so the sole source of stability was the crystalline structure formed during annealing. peppas n.a.,and tennenhouse d.[11] study the preparations semicrystalline films of poly vinyl alcohol by annealing amorphous pva films at temperature 90, 100, 110 o c for 60 min, the degree of crystallinity of the dry films was measured by differential scanning calorimetry[12,13]. in this work, special emphasis is given to the methods of preparation, the optimization of the preparation process and the swelling behavior of the associated systems. experimental work 1. pva film preparation the films produced were made from a 13% and 11.5% aqueous pva solution. to prepare 13% pva solution,35 ml of deionized water was added to 5.3 g pva(mw=14000 , degree of hydrolysis=99.8%).to prepare 11.5% pva solution,45 ml of deionized water was added to 5.3 g pva(mw=14000,degree of hydrolysis 99.8%). the pva solution was stirred and heated at 8590°c for 4 to 6 h by using a water bath. the solution was allowed to cool for several minutes before use. the solution was then cast on to six 25.4x76.2 mm glass slides and spread uniformly over the slides using a glass rod. the films were allowed to dry at 25-30°c for at least 24 h. basma a. abdul-majeed, hussain k. hussain and nagam a. kafel al-sultanee -available online at: www.iasj.net ijcpe vol.13 no.2 (june 2012) 31 2. annealing of the films the amorphous pva and films were annealed in an oven at temperatures 90,110 and 120°c for 15,30 and 60 min with concentrations of 13% and 11.5% aqueous pva films. once the films were removed from the oven and then peeled off from the glass slides and stored at room temperature. the resulting hydro gels were tested for their crystalline, swelling behavior,gel fraction and solubility. tests of the films 1. water uptake the samples were submerged in deionized water at 37°c (the last level simulates water absorption at the temperature of the human body) until they reached equilibrium, which occurred after three to four days. after swelling, the weight and volume of the samples were again measured. the water uptake, or percent water incorporated into the hydrogel was calculated from eq.1. …(1) where is the weight of dry sample and is the weight of swollen sample. the swelling behavior of pva films was studied by measuring the amount of water incorporated into the sample. after the annealing process, the samples were weighted then swollen in water, later the swelling samples were weighted after swollen every two days nearly until the amorphous pva was soluble. 2. calculation of the samples volume volumetric measurements were taken by suspending the sample in heptane (a non-solvent), weighing, and calculating the volume, v, based on the weight of the heptane displaced. first the samples were weighing in air and then volumetric measurements were taken by suspending the sample in nheptane, weighing, and calculating the volume, v, based on the weight of the heptane displaced. the volume, v, was calculated by eq.2. v = (wair wheptane) /ρheptane …(2) where wair is the weight of the sample in air, wheptane is the weight of the sample in heptane and ρheptane is 0.6840g/ml. 3. density of gels the density of dry gels was determined by hydrostatical weighing by [kit ydk 01lp in n-heptane (en 1183-1:2004)]. the density of gels was calculated by eq.3. …(3) where is the weight of the sample in air, is the density of the liquid (nheptane), and is the weight of the sample in the liquid. 4. degree of crystallinity the semicrystalline films were characterized by measuring the degree of crystallinity, x, after annealing. the degree of crystallinity of the samples was calculated by eq.4: …(4) where a =1.345 g/cm³ for 100% crystalline pva, =1.269 g/cm³ [ 89 ] for 100%amorphous pva, and is the density of the sample. the “wet degree of crystallinity” xwet, was calculated by eq.5. this value indicates the volume of crystallites in the hydrogel compared to the total volume of the swollen hydrogel. xwet = x * vdry / vswollen …(5) effect of annealing on the crystallization of poly vinyl chloride for drug delivery system 32 ijcpe vol.13 no.2 (june 2012) -available online at: www.iasj.net to calculate the degree of crystallinity x of the samples, first the dry annealing films were weighted in air and then in n-heptane; after that the were samples swollen in water by using magnetic stirrer for 4h, and later the swollen samples were weighted in air heptane once more. results and discussion effect of annealing temperature on the water uptake of pva films thin films of pva were annealed at temperatures of 90, 110 and 120 o c( above the glass transition temperature of 85°c) for 15 min to investigate the effect of annealing temperature on water uptake of the films. fig.1 and fig 2 show that water uptake increased with time until it reached nearly constant value after 20 day. water uptake was decreased with increasing annealing temperature for 13% and 11.5% pva related to the effect of density of the films. the increasing of density was caused by the effect of annealing temperature on the inner composition of the polymer. increasing the temperature of annealing caused in compacting of polymer molecules which result in decreasing the voids among polymer molecules. consequently the porosity decreased and the permeability of the polymer for liquids and gases decreased [14]. this behavior indicates clearly the increase in the crystalline phase in comparison with the amorphous one, or it can be said that the system is more packed with crystallite. fig.1, relation between water uptake and time of swelling for different annealing temperature, t=15 min, 13% pva fig.2, relation between water uptake and time for different annealing temperature, t=15 min, 11.5% pva effect of annealing time on the water uptake of pva films the effect of annealing time on the water uptake of polyvinyl alcohol films was investigated. the films of pva were anneallied for different times (15, 30 and 60 min) at annealing temperature of 120 o c. figures 3 and 4 show the effect of annealing time on the water uptake with constant annealing temperature using 13% and 11.5% pva, respectively. these figures illustrate that increasing the annealing time causes decreasing the water uptake, which can be attributed to the increase in density. 40 45 50 55 60 65 70 75 0 10 20 30 w a te r u p ta k e day t=90 °c t=110 °c t=120 °c 0 10 20 30 40 50 60 70 80 0 10 20 30 w a te r u p ta k e day t=90 °c t=110 °c t=120 °c basma a. abdul-majeed, hussain k. hussain and nagam a. kafel al-sultanee -available online at: www.iasj.net ijcpe vol.13 no.2 (june 2012) 33 fig.3, relation between water uptake and annealing time for t=120 o c, and 13% pva fig.4, relation between water uptake and annealing time for t=120 o c and 11.5% pva effect concentration of pva on the water uptake of pva films the effect of the concentration of pva on the water uptake of polyvinyl alcohol films with time was investigated. the pva films were annealed at constant temperature of 120 o c for constant annealing time of 30 min to investigate the effect of the concentration of pva on the water uptake of the films. figure 5 shows the effect of increasing concentration of pva on water uptake with time of swelling. the increase in polymer concentration leads to a decrease in the water uptake of the films. from the results of the previous sections, increasing the density caused the decreasing of the water uptake of the polymer; increasing the concentration means the increasing of the density, thus the increasing of the polymer concentration carried out the decreasing of the water up take which was caused by the decreasing of the permeabilityof the polymer. the increase in the density means that the interstituoas distance between the adjacent molecules will become less leading to less porosity and hence less water uptake. during the annealing process, some of the amorphous phases changes into folded compact chains which are distributed through the amorphous phase. this can be considered as crosslinking but of physical type. these points of physical crosslinkings are considered as crystals or crosslinking agents or centre. fig.5, relation between water up take and swelling time for different concentration of pva at annealing temperature of 120 o c and annealing time of 30 min effect of annealing temperature on the degree of crystallinity of pva films the effect of annealing temperature on the degree of crystallinity of polyvinyl alcohol films was investigated. fig.6 shows the effect of the annealing temperature on the degree of crystallinity with different annealing time. the increase in the annealing temperature leads to the increase of the degree of crystallinity, which results from increasing the density of the polymeric samples. the annealing process causes the appearance of aggregation of the polymer chains; consequently the crystal regions will grow with the increase of annealing temperature [10,13]. the physical 35 45 55 65 75 0 5 10 15 20 25 30 w a te r u p ta k e day t=15 min t=30 min t=60 min 0 10 20 30 40 50 60 70 80 0 10 20 30 w a te r u p ta k e day t=15 min t=30 min t=60 min 20 25 30 35 40 45 50 55 60 0 10 20 30 w a te r u p ta k e day 11.5% pva 13% pva effect of annealing on the crystallization of poly vinyl chloride for drug delivery system 34 ijcpe vol.13 no.2 (june 2012) -available online at: www.iasj.net crosslinking causes the polymer to be packed with crystals with less inner distances. fig.6, relation between the degree of crystallinity of pva and annealing temperature for different annealing time, 11.5% pva effect of annealing time on the degree of crystallinity of pva films the effect of annealing time on the degree of crystallinity of polyvinyl alcohol films was investigated as show in fig.7. the degree of crystallinity increased with increasing time of annealing. comparison between dry and wet crystallinity of pva films a comparison between dry and wet crystallinity of polyvinyl alcohol films at different temperatures and constant annealing time was investigated as shown in fig.8, while fig. 9 shows a comparison between the dry and wet crystallinity of the samples annealed for different annealing times at constant temperature. as expected, the rate of swelling differs in both dry and wet films. the wet crystallinity of the samples was much lower than that of the dry crystallinity. this was readily explained by the water incorporated into the polymer network during swelling. the amorphous regions of the hydrogel swelled, allowing water to penetrate the network and became entrained in the hydrogel. this expansion of the network and incorporation of water caused the overall weight and volume of the hydrogels to increase during swelling. fig.7, relation between the degree of crystallinity and time of annealing for different annealing temperature, 11.5% pva fig.8, relation between the degree of crystallinity and temperature of annealing for dry and wet films fig.9, relation between the degree of crystallinity and time of annealing for dry and wet films 54 56 58 60 62 64 66 85 95 105 115 125 d e g re e o f cr y st a ll in it y temp. of annealing t=15 min t=30 min t=60 min 53 55 57 59 61 63 65 5 10 15 20 25 30 35 40 45 50 55 60 65 d e g re e o f cr y st a ll in it y time of annealing t=90 °c t=110 °c t=120 °c 0 10 20 30 40 50 60 70 85 95 105 115 125 d e g re e o f cr y st a ll in it y temp. of annealing x xwet 0 20 40 60 80 10 30 50 70 d e g re e o f cr y st a ll in it y time of annealing x xwet basma a. abdul-majeed, hussain k. hussain and nagam a. kafel al-sultanee -available online at: www.iasj.net ijcpe vol.13 no.2 (june 2012) 35 long-term stability of hydrogels long term stability of hydrogels was investigated. as noticed from the previous results, the increasing of annealing temperature and time of annealing causes the decreasing of the water uptake, and since the gel fraction is a function of the water uptake; therefore the gel fraction behaves exactly the same as the water uptake. on the other hand the solubility is inversely proportional to the crystallinity, or it behaves inversely. fig. 10 shows the effect of annealing temperature and time of annealing on gel fraction of pva films, where the increasing of annealing temperature and time of annealing causes the decreasing of the gel fraction. fig.11 shows the effect of annealing temperature and time of annealing on the solubility of the pva films, where the increasing of annealing temperature and time of annealing results in the decreasing of the solubility. fig.10, relation between gel fraction of the polymer and annealing time at different annealing temperature, 11.5% pva fig.11, relation between solubility of the polymer and annealing time at different annealing temperature, 11.5% pva conclusions increasing the annealing temperature leads to a decrease in water uptake, an increase of density, and an increase of the crystallinity of pva films with constant time of annealing. increasing time of annealing leads to decreasing in the water uptake, increasing density and increasing of the crystallinity of pva films at constant annealing temperature. increasing density leads to decreasing in the water uptake and increasing crystallinity of the pva films. the wet crystallinity of the samples was much lower than that of the dry crystallinity for the pva films. the results show that increasing the annealing temperature and annealing time causes the decrease of the gel fraction and solubility for the pva films. references 1. peppas n.a., huang y. polymers and gels as molecular recognition agents. pharmac. res., 19, 578587, 2002. 2. santini, j., john t., et al., "microchips as controlled drugdelivery" devices. angewandte chemie international edition, 2000. 39(14): p. 2396 2407. 3. peppas, l.b., polymers in controlled drug delivery, in 110 135 160 185 210 235 260 285 310 335 360 10 30 50 70 g % annealing time t=120 °c t=110 °c t=90 °c 11.5% pva 0.05 0.06 0.07 0.08 0.09 0.1 10 30 50 70 s % annealing time t=90 °c t= 110 °c t=120 °c 11.5% pva effect of annealing on the crystallization of poly vinyl chloride for drug delivery system 36 ijcpe vol.13 no.2 (june 2012) -available online at: www.iasj.net medical plastics and biomaterials magazine. 1997. p. 34-46. 4. peppas n .a . and korsmeyer r .w." hydrogels in medicine and pharmacy", peppas n .a., ed ., crc press, flo., 3, 110-129 (1986). 5. peppas n .a., "hydrogels of poly(vinyl alcohol) and its copolymers", in :hydrogels in medicine and pharmacy, peppas n.a ., fd ., crc press, flo., 2, 1-48 (1986). 6. peppas n.a. crystallization of pva-water films by slow dehydration. – eur. polym. j., 12, 495-498, 1976. 7. hassan c.m., peppas n.a. longterm morphological changes in freeze-thawed pva hydrogels. polym. mater. sci. eng. proceed., 79, 473474, 1998. 8. hassan c.m., stewart j.e., peppas n.a. diffusional characteristics of freeze/thawed pva hydrogels: applications to protein controlled release from multilaminate devices. eur. j. pharm. biopharm., 49, 161-166, 2000. 9. mallapragada s.k., peppas n.a. dissolution mechanism of semicrystalline pva in water. j. polym. sci., polym. phys., 34, 13391346, 1996. 10. mallapragada s.k., peppas n.a. effect of dissolution on lamellar thickness distribution of semicrystalline poly (vinyl alcohol). – polym. mater. sci. eng. proceed., 73, 22-23, 1995. 11. mallapragada s.k., peppas n.a. crystal unfolding and chain disentanglement during semicrystalline polymer dissolution. aiche j., 43, 870-876, 1997. 12. peppas n.a. tennenhouse d., drugdeel j. sci.teche., 14(4) 291297 2004. 13. jolanta stasko, martiņs kalniņs, anda dzene, and velta tupureina,proceedings of the estonian academy of sciences,2009, 58, 1, 63–66. 14. peppas n.a. tennenhouse d., drugdeel j. sci.teche., 14(4) 291297 2004. iraqi journal of chemical and petroleum engineering vol.17 no.2 (june 2016) 4752 issn: 1997-4884 study the efficiency of drilling with casing operation in an iraqi oil field ayad a. alhaleem university of baghdad / college of engineering petroleum department abstract drilling with casing (dwc) can be considered as a modern drilling technique in which both of drilling and casing operations done in the same time by using the casing to transfer the hydraulic and mechanical power to the bit instead of traditional drilling string. to overcome oil well control, minimizing the total cost through enhancing drilling efficiency, drilling with casing was proposed as an enabling technology. two surface sections (17 1/2 and 12 1/4inch) were drilled successfully in rumaila oil field with casing strings which reached 655m and 1524m measured depths respectively. by using dwc technique, the total drill/case phase time was reduced up to 20% comparing to conventional drilling in the same field . drilling both sections with dwc system eliminating the number of trips and nonproductive time (npt) related to wellbore instability. key words: casing drilling, bha, drill string, tripping, cds. introduction casing drilling technology can be considered as one of the most important developments in drilling operations. it is an effective method to reduce the over drilling costs by reducing drilling time and drill string problems associated with conventional drilling process [1]. there are two basic method of drilling with casing [2]: 1a latched retrievable bottom hole assembly (bha) inside the casing that incorporates a motor to drive a conventional bit and under-reamer. 2a rotate the casing at surface system incorporating an internal casing drive system and a drillable “cement in place” drilling bha. in general, designing a well to be drilled with casing drilling technique is similar to designing a conventional well. the most important significant difference is that the casing in the well is subjected to additional stresses while casing drilling, so buckling, fatigue, and hydraulics deserve special attention [3]. drilling with casing has proven many advantages for certain classes of wells, i.e., wells which have low deviations. actually, with providing good directional control, casing drilling would be beneficial for limited iraqi journal of chemical and petroleum engineering university of baghdad college of engineering study the efficiency of drilling with casing operation in an iraqi oil field 48 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net step-out, shallow extended reach drilling (erd) wells [4]. the new method of drilling the timedevelopment figa formation using dwc allows well engineers to suggest perspective top/intermediate well bore sections differently by enhancing the overall drilling performance. the risk of setting casing strings at unplanned depth is reduced through this plan besides the reduction in getting pipe stuck [5]. many results in a more stable well bore can be achieved with casing drilling since casing stays in the hole at all times. every inch of hole drilled can be kept, even if well control problems or well stability force the casing to be set and cemented prior to the full interval being drilled [6]. site observations in the selected well, the top section (17 1/2 inch hole) which include dibdibu, lower fiars, ghar formations are drilled with the known bottom hole assembly (bha), while dammam formation is drilled by casing with the availability of casing drive system (cds) tool. this tool is connected from the top with top drive and from the bottom it will be inside the casing (as the first component) to drill with casing. the mentioned tool is not regular for the local companies and it was used by schlumberger companyin south rumaila. here in this section , the drilling was done with drillable bit which considered as one usage tool since the next drilling will be finished with pdc bit (from 520m to 655m). the implementation of dwc technique in dammam can be attributed to the main reason named complete losses. the treatment of this problem with several usages of cement blocks which may be reached in certain conditions to more than twenty blocks can cause an increasing in whole drilling time. the increasing in loosing time, cost and materials consumption (as mud or cementing) leads to consider a dwc as a better option to prevent many drilling problems. consequently, dwc technique was used in hartha and tayarat formations (12 1/4 inch hole). table (1) represents the lithology and mechanical state of the selected well in which two sections were planned and practiced with dwc process [7]. table 1, lithology and mechanical state of the selected well [7] formation potential risk didbba caving l.fars caving, heavy oil in shely limestone dammam partial to complete mud losses may rus umm-radhuma sulphurous water may flow tayarat sulphurous water may flow tight hole shiranish tight hole hartha mud loss may occur, tight hole sadi tight hole tanuma caving khasib mishrif rumaila ahmadi maudud nahrumr caving shuaiba mud loss may occur zubair medium oil impregnation in sandstone ratawi ayad a. alhaleem -available online at: www.iasj.net ijcpe vol.17 no.2 (june 2016) 49 hartha formation have the losses problem and tayarat formation have a potential risk of sulphurous water flow which results a changing in drilling mud properties due to presence of h2s and the failure in cement blocks. so the dwc was considered a best option to deal with such problems. well planning surface hole sections in rumaila oil field are almost drilled with large diameter bits (17 1/2 – 26 inch; pdc) using fresh water bentonite (fwb) and a standard rotary bha. the two holes are cased with 133/8-in and 20 in respectively. the next sections in both wells are commonly drilled with 121/4 and 81/2 pdc bits and cased with 9 5/8 and 7 inch casing respectively. the major components of the casing while drilling system are [9]: 17 1/2″ bit +1 float collar +1 13 3/8″casing +1 float collar +13 3/8″casing. in comparison with traditional drilling for the same hole, the components of bha and drill string are: 17-1/2″ bit +bit sub with float +2 91/2″ dc +roller reamer 17-1/2″ + cross over+ 6 8″ drill collar + hydroulic jar +2 8″ drill collar + cross over + 6 6-3/4″ collar + 15 5″ hwdp + 5″ 19.50 g-drill pipe. it can be seen from the above bha and drilling design, the dwc need less components which consequently means no more trips were needed to improve drilling conditions. the same note can be observed while examining the bha and drill string components of 121/4″ section which can be summarized as: 121/4″ insert bit + near bit stab. with fv. + 1 8″ drill collar + string stabilizer + 2 8″ drill collar + string stabilizer + 11 8″ drill collar + jar +2 8″ drill collar + x/o + 3 63/4″ drill collar + 15 hwdp + 5″ 19.50 g drill pipe. similarly, the major components of casing while drilling for 12-1/4″ hole are: 12-1/4″ bit + float collar + stabilizer + 1 95/8″ casing joint +1 float collar + 9-5/8″ casing joint. absolutely the optimization in no need to drilling pipes and collar pipes with dwc technique can be considered advantage for both of the whole drilling operation and drilling contractors. figure (1) and (2) show a schematic diagram of bha and drill string for casing drilling for 17-1/2″ hole section and 12-1/4″ hole section respectively. it can be seen from the given figures that fit for purpose stabilizer in 12-1/4″ hole section to reduce the chance of buckling, while no stabilization is needed in 17-1/2″ hole section. fig 1, schematic diagram of bha and drill string design of 171/2 inch hole study the efficiency of drilling with casing operation in an iraqi oil field 50 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net fig 2, schematic diagram of bha and drill string design of 12 1/4 inch hole results and discussion generally, in any drilling operation, the hydraulic energy besides the mechanical energy represents the major power components to optimize drilling efficiency. table (2) shows the hydraulic parameters for both rotary drilling and casing drilling through 171/2″ hole section. table 2, hydraulic parameters for rotary drilling and casing drilling [7] parameters rotary drilling casing drilling wob (mt) 5-12 2-14 rpm 120-130 40-60 expected rop (m/hr) 10-15 4-7 his (hp/in 2 ) 2.21 @ 3780 l/min 0.14 @ 2250 l/min pump pressure (psi) 2415@ 3780 l/min 181 @ 2250 l/min flow rate (l/min) 2270 l/min (first 30m) 3780 l/min 2250 l/min as shown from table (2), there is an important parameter used in drilling hydraulics to show a better understanding about the magnitude of the hydraulic horsepower. this term is called the h.s.i (hydraulic horsepower per square inch of bit face area) and is basically obtained by dividing the hydraulic horsepower by a hole size [8]. although that the rate of penetration with dwc is less than rotary drilling, but the whole drilling time is optimized. using normal drilling at tight formations can cause borehole instability and many other problems which can be prevented by using dwc technique. providing enough hydraulic energy is required to prevent bit balling, to avoid cuttings accumulation inside annulus and flow line and finally to reduce overall energy consumption. the proper analysis of mechanical factors can give the following issues:  collapse and burst rating of drill pipe is many times larger than that of large-diameter casing which can be attributed to unrestricted and large internal diameter casing which ayad a. alhaleem -available online at: www.iasj.net ijcpe vol.17 no.2 (june 2016) 51 reduces maximum stand pipe pressure.  high torque up to 80klbs can be achieved when drilled 171/2″hole section starting with 5-6 kft.lb. these values are many times larger than in apidp (american petroleum institute drill pipe) to allow them to repel greater axial and torsional loads than traditional joints. so, fatigue-related washouts in the pipe body and risks of twistoff during dwc operations are negligible. implementation of dwc showed the following advantages: 1reducing the nonproductive time (npt) through overcome the following concepts the kick during drill string pulling, sloughing formations within swab and surge, pipe sticking, and key seat. 2the cementing operations was successfully implemented and proved by cement-bond log (cbl) which revealed good cement bonding. 3reduction on total drilling cost through the following concepts: a. reduction on whole drilling problems. b. having perfect cementing operation. c. less environmental impacts compared with traditional methods due to less drilling time, less pumps pressure which result in less fuel consumption. drilling with casing results in less casing rotating and which restrike or prevent fluid loss to the production formation and reduce flushing of mud filtrates to the permeable zone where the accumulation of drill cuttings inside the sections of high permeability and porosity at the top of annulus which finally help in well stability. the application of drilling with casing technique for two sections in the selected well save the operator 14 rig days which representing a significant cost reduction, fig (3). fig 3, comparison between conventional drilling and dwc days certainly, reducing the rig time by 20% saved millions of dollars to the operator. one concern about drilling with casing is the likely need to modify the rig to undertake drilling with casing. one of the best important modifications on rig is casing drive system (cds) which offers safe and non-threaded connection between casing string and top drive. in spite of lack of local experience in dwc technique, the potential problems which likelihood of occurrence during drilling the selected sections were prevented or limited. study the efficiency of drilling with casing operation in an iraqi oil field 52 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net conclusions the results of the present study indicate that: 1problems attributed to pipe tripping can be reduced with cds in addition to reduce surge and swab pressure punctuations. 2it is important to know that evaluation of lithological characteristics of the formations and hole conditions is very important prior to apply certain design criteria of the casing to improve drilling performance. 3casing drilling has proven benefits for the application southern iraqi oil field (especially for vertical well) where low torques and loads are commonly created during dwc process. 4dwc process provided efficient hole cleaning through presence of mono diameter annular geometry which gave higher annular velocities. 5eliminating swab/surge effect resulting in higher reducing of risks of well control incidents. 6the additional stresses which casing is subjected to (in dwc) need the operator to deserve special attention to bucking, fatigue and hydraulics. abbreviations api american petroleum institute bha bottom hole assembly cbl cement bond log cds casing drive system dc drill collar dwc drilling with casing erd extended reach drilling fwb fresh water bentonite hsi hydraulic horsepower square inch of bit hwdp high weight drill pipe mt metric ton npt non productive time pdc poly crystalline diamond bit rop rate of penetration rpm revolution per minute wob weight on bit references 1nediljka g. medimurec: casing drilling technology, rudarsko geolosko-naftnizbornik, vol. 17, pp19-26, 2005. 2fisher, a., reid., zo tan, m., galloway, g.: extending the boundaris of casing drilling, paper iadc/spe 87998, presented at the iadc/spe asia pacific drilling technology conference and exhibition, kuala, lumpur, malaysia, 13-15 september 2004. 3warren, t, m, angman, p., hountchens, b.: casing drilling: application considerations, paper iadc/spe 59179, presented at the 2000 iadc/spe drilling conference, new orleans, louisiana, 23-25 february 2000. 4mason, c.j., lopez, j., meling, s., murger, r., fraser, b.: casing running challenges for extended reach wells, paper spe 84447, presented at the spe annual technical conference and exhibition held in denever, 2003. 5sanchez, f., hougani , s., turki, m., gruz, m.: casing while drilling (cwd): a new approach to drilling figa formation in the sultanate of omana success story, spe drilling &completion , june 2012. 6michael, k., drilling with casing gains industry acceptance, the american oil & gas reporter, april 2005. 7south oil company, final drilling report, rumaila oil field, 2010. 8scott, a.h.: drilling performance optimization, texas, 1975. iraqi journal of chemical and petroleum engineering vol.17 no.2 (june 2016) 1523 issn: 1997-4884 adsorption of fluoroquinolones antibiotics on activated carbon by k2co3 with microwave assisted activation ammar s. abbas, muthana j. ahmed and teeba m. darweesh chemical engineering department, college of engineering, university of baghdad abstract the preparation of low cost activated carbon from date stones and microwave method by using k2co3 as chemical activator were investigated. the prepared activated carbon was used to remove fluoroquinolones antibiotics from aqueous solution. the characterizations of the activated carbon is represented by surface area, pore volume, ash content, moisture content, bulk density, and iodine number. the adsorbed fluoroquinolones antibiotics are ciprofloxcin (cip), norfloxcin (nor) and levofloxcin (levo). different variables as ph, initial concentrations and contact time were studied to show the efficieny of prepared activated carbon. the experimental adsorption data were analyzed by lungmuir, freundlich, and temkin isotherm. the experimental results are described by lungmiur isotherm. the kinetic data were fitted to pseudo-first order kinetics, pseudo-second order kinetics and interparticle diffusion model. the kinetic adsorption data were best fitted by psuedo-second order kinetic. key words: date stone, activated carbon, microwave, fluoroquinolones antibiotics, adsorption isotherm, kinetics introduction fluoroquinolones are synthetic antibiotics; they are a minor group from the major family quinolones. they form a unique group among the bactericidal drugs that used in community sectors, hospitals, and veterinary medicine [1]. fluoroquinolones have many advantages that enabled them to be ideal antibiotics. they have high potency, good bioavailability, excellent activity against many type of bacteria included gram-positive and gramnegative bacteria, intravenous and oral formulations, low binding and a large distribution volume that made them cross the membranes easily and reach the remote part of human body and low side-effects [2]. some of fluoroquinolones are used before surgery to prevent inflection; also some of them are studied because they are useful in biliary tract surgery and eye surgery [3-4]. activated carbon is an excellent adsorbent that is used to remove different organic or inorganic pollutant from many aqueous solutions. various agriculture wastes or lignocellulose materials such as cotton stalk, date stones, rice husks, apricot stones, olive stones, and almond shell are used to prepare activated carbon [5-8]. the iraqi journal of chemical and petroleum engineering university of baghdad college of engineering adsorption of fluoroquinolones antibiotics on activated carbon by k2co3 with microwave assisted activation 16 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net selection of activation method and raw material are important in controlling the physical and chemical characterization of the prepared activated carbon [9-10]. the use of the thermal heating is to enhance surface chemistry and structure of pores [1112]. microwave heating is a successful method that is used for preparation and regeneration of activated carbon [1314]. the microwave would supply energy to the carbon partials. this energy would convert into heat by ionic conduction within the particles themselves. microwave heating have many advantages such as uniform distribution in temperature, rapid temperature rise, high heating rate, heating process can be controlled easily, reduce the treating time, and saving energy [15-16]. adsorption is either physical or chemical surface phenomenon in which the concentration of vapor, gas, and liquid accumulate at the contact surface are either undergoing a chemical reaction or not, forming an interface or surface [17]. adsorption by activated carbon has many advantages over other method as low preparation cost, simple, and free design [18]. the aim of the current work is to study the ability of date stones-carbon for removing the fluoroquinolones antibiotics such as cip, nor, and levo from solutions. the equilibrium and kinetic adsorption rate are also investigated to understand the mechanism of adsorption. material and method material date stones were used in this work to prepare the activated carbon. firstly, the date stones were washed with water to remove the impurities and then dried at 110 °c for 24 h. the date stones were crushed by using disk mill. finally, the average particle size 1 to 2 mm. k2co3 (provided by didactic company, espuma) with purity of 99.9%, were used as chemical activator for preparation of activated carbon. the fluoroquinolones antibiotics used are: cip of purity 99.9% are provided by nanjing huaxin biofarm. company ltd., china, nor with purity 99.9% are provided by ajanta pharma limited company, india. preparation and characterization a stainless steel reactor with 3 cm diameter * 15 cm length that was closed in one end and the other end had a removable cover containing a 1mm hole in the middle of it for escaping pyrolysis gases. date stones (20g) were put in the reactor and heated in an electrical furnace at 500°c for 1h, then, allowed to cool to room temperature. each 2 g of the sample above were mixed with 10 ml k2co3 solution with impregnation ratio 0.8 g/g at room temperature for 24 h then they are put in the oven at 110°c until complete drying. the microwave activation step includes using a quartz reactor 3 cm diameter and 13 cm length. the reactor was closed in on end and the opened to a stainless steel pipe with inside diameter of 5mm. the dried sample was put in the reactor and the reactor put in a microwave oven (mm717cpj, china) with radiation power 540 w for 8 min radiation time. then, the sample allowed to cool and socked with 0.1 m hcl solution (10ml/g liquid to solid ratio) for 24 h at room temperature. finally, drying sample in the oven at 110 °c for 24 h and weighing the sample to calculate the yield. the prepared activated carbon was stored in desiccator. ammar s. abbas, muthana j. ahmed and teeba m. darweesh -available online at: www.iasj.net ijcpe vol.17 no.2 (june 2016) 17 the characterizations of activated carbon were represented by surface area, pore volume, ash content, bulk density, moisture content, and iodine number. fig. 1, schematic diagram of microwave unit for preparation of activated carbon adsorptive removal the effect of ph, concentration of antibiotics, and contact time were studied by using batch mode adsorption experiment to show the percentage removal of cip, nor, and levo. a 0.1 gram of prepared activated carbon with particle size 0.5 to 1 mm was added to 100 ml solution of cip, nor, and levo with different initial concentration (50 to 200 ppm) and different ph (3 to 11). these mixtures were added to 250 ml flask and shaken at 200 rpm for different periods (15 to120 min). then, the samples were filtered and the concentrations of antibiotics were measured by using uv-visible spectrophotometer at wavelength of 272, 274, and 290 nm for cip, nor, and levo respectively. the following equation was used to determine the percentage removal of each antibiotic at any time: ( ) 10 (1) wh d / is the initial and equilibrium concentration of each antibiotics adsorption isotherms three important isotherms have been used to correlate the experimental date of cip, nor, and levo namely lungmuir, freundlich, and temkin [19-20]. their equations as follows: h 1 2 d h h 1/ 3 h 4 where ql (mg/g) is the maximum adsorption capacity, kl (l/mg) is the lungmuir isotherm constant related to the rate of adsorption, kf ((mg/g) (l/mg) 1/n ) and n is freundlich constant, related to adsorption capacity and adsorption intensity, respectively. b is the temkin constant means adsorption heat and a (1/mg) is the constant that related to equilibrium energy. adsorption kinetic a set of batch mode experiments were carried out to study the effect of contact time on adsorbed amounts of antibiotics to calculate the equilibrium time. the concentration of antibiotics was measured by taking samples of solution at different periods. the adsorbed capacity at time t, qt was calculated by: ( ) w 5 where ct (mg/l) the concentration of antibiotics at time t (min), mg/l, v (ml) volume of antibiotic solutions, w (mg) adsorption of fluoroquinolones antibiotics on activated carbon by k2co3 with microwave assisted activation 18 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net weight of activated carbon. kinetic rates were analyzed with three kinetic models to calculate the rate controlling step and the mechanism of adsorption [21-22]. these models are: pseudo-first order model ln( qtqe) = ln qe – k1 t (6) pseudo-second order model 1 (7) interparticle diffusion model qt = k3 t 1/2 + c 8 where qe and qt are the uptake of antibiotic at equilibrium and at time t min, respectively, k1 min -1 is the adsorption rate constant, k2 (mg/g. min) and k3 (mg/g. min 1/2 ) the rate constant of second order and interpartical diffusion respectively, c (mg/g) constant related to the thickness of boundary layer. results and discussions yield and characteristics the yield and characteristics of prepared activated carbons are listed in table 1. from this table, the yield is 44% for prepared activated carbon. these results are higher than that found by haimour and emeish [23], for activated carbon prepared from date stones activated by phosphoric acid. their prepared condition 800 ᵒc activation temperature and 0.4 impregnation ratio and 1h activation time. they showed 44% yield. the higher recorded yield of the current results may be due to the use of microwave method that allows activation with lower temperature than 500 °c which reduces the burn off. table 1, characteristics of prepared activated carbon characteristics value surface area, m 2 /g 852 pore volume, cm 3 /g 0.671 ash content, % 3.88 moisture content, % 4.9 bulk density, g/ml 0.352 iodine no. 854.9 yield, % 44 the surface area and the iodine number are the most important characteristics. the surface area of prepared activated carbon was 852 m 2 /g and this result is in agreement with the result of bamfuleh [24] who reported that the surface area of activated carbon from date stones and zinc chloride activation was in the range of 802 to 1270 m 2 /g. the iodine no. of the activated carbon is 854.9, it's higher than the iodine no. of activated carbon prepared from date stone activated by phosphoric acid 459 that was prepared by haimour and emeish [23]. this may be due to the higher micropore content of the activated carbon that prepared by k2co3 of this work. fig. 2, effect of time on the removal of cip, nor and levo ammar s. abbas, muthana j. ahmed and teeba m. darweesh -available online at: www.iasj.net ijcpe vol.17 no.2 (june 2016) 19 effect of time the effect of contact time on percentage removal of activated carbon on each of fluoroquinolones antibiotics at initial concentration of 150 ppm is shown in figure 1. the percentage removal increases with increasing contact time and reaches equilibrium after 90 min. the maximum percentages removal are 64.4, 62 and 65.7 % for cip, nor, and levo respectively. the percentages removal increases rapidly during the first 45 min, this may be due to the higher driving force which made the transfer of adsorption ions to the particles of activated carbon fast. wang et al. [25] and zhang et al. [26] also showed an equilibrium time of 100 min for antibiotics adsorption on coal fly ash. ahmed et al. [27] also showed a 90 min equilibrium time for cip adsorption by albizia lebbeck activated carbon. effect of antibiotics initial concentration the effect of different initial concentration on adsorption capacity of the prepared activated carbon on each type of fluoroquinolones antibiotics for 24 hours is shown in figure 2. from this figure, it is obvious when the initial concentration increases from 50 ppm to 200 ppm, the adsorption capacity, (qe), increases from 49.28 to 103.06 mg/g, 49.09 to 102 mg/g, and 49.47 to 106.8 mg/g for cip, nor, and levo, respectively, reach equilibrium at the concentration of 250 ppm. foo et.al [28] showed an increases in adsorption capacity from 51.06 to 398.45 mg/g when the initial concentration increase from 50 to 500 mg/l. fig. 3, effect of the initial concentration of cip, nor and levo on the adsorption capacity of activated carbon effect of ph in this work different ph from 3 to 11 antibiotic solutions were used to study the percentage removal of each antibiotic on the prepared activated carbon. figure 3 shows the effect of different ph at the percentage removal with initial concentration 150 ppm for 24 hours. for cip and levo the maximum percentage removal are 67.9 and 69.8 %, respectively at ph = 9 and percentage removal of 66.4 % at ph=5 for nor. sun et al. [29] and ahmed et al. [27] considered a ph equal to 8.7 and 9 respectively to be the best ph value for maximum percentage removal for cip. liu et.al. [30] showed that the ph= 5.5 is the best value for adsorption of nor on lotus stalk-activated carbon adsorption. adsorption of fluoroquinolones antibiotics on activated carbon by k2co3 with microwave assisted activation 20 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net fig. 4, effect of ph on the removal of the different antibiotics by activated carbon adsorption isotherm the three isotherms, lungmuir, freundlich, and temkin isotherms, eqs. 2, 3, and 4 were used to fit the experimental adsorption data of the three antibiotics. table 2 shows the calculated constants of the three isotherms with correlation coefficient (r 2 ) values. table 2, adsorption isotherm parameters for adsorption of the antibiotics by activated carbon adsorbate lungmuir isotherm qm(mg/g) kl (1/mg) r 2 cip 101.7 0.01 0.999 nor 99.71 0.007 0.9989 levo 104.76 0.0112 0.9995 adsorbate freundlich isotherm kf((mg/g)(1/mg) 1/n ) n r 2 cip 1.544 1.371 0.4188 nor 1.478 1.308 0.4498 levo 1.607 1.42 0.3723 adsorbate temkin isotherm a (1/mg) b r 2 cip 1.01 90.53 0.7496 nor 1.009 87.51 0.7864 levo 1.013 92.64 0.717 the highest r 2 values is for lungmuir isotherm for all three antibiotics with maximum adsorption capacity of 101.7, 99.71 and 104.76 mg/g for cip, nor, and levo respectively. this may be explained by that the surfaces of prepared activated carbons have homogenous distribution active sites. many researchers showed a successful application of lungmuir isotherm to correlate the experimental data that used for adsorption on activated carbon [31-32]. adsorption kinetics the kinetic data for antibiotic adsorption are fitted to three kinetic models: pseudo-first order model, pseudo-second order model, and interparticle diffusion model (equations 6 to 8). the results are summarized in table 3. the experimental data is better represented by pseudo-second order kinetic model because it gave higher r 2 values while the low r 2 values were for pseudo-first order model. also for pseudo-first order model a large difference between the calculated and experimental adsorption capacity which indicate a poor model. these results are in agree with several authors who used agricultural precursors to prepare activated carbon for adsorption of antibiotic [30-33]. from table 3 the lowest r 2 values were obtained for interparticle diffusion model compared with the pseudo-first order and pseudo-second order models. also large difference between the experimental and calculated data of adsorption capacity. ammar s. abbas, muthana j. ahmed and teeba m. darweesh -available online at: www.iasj.net ijcpe vol.17 no.2 (june 2016) 21 table 3, absorption kinetics of antibiotics over activated carbon adsorbate pseudo-first order model qe,exp(mg/g) qe,cal (mg/g) k1 (min) -1 r 2 cip 97.4 30.144 0.033 0.826 nor 93.3 31.28 0.034 0.823 levo 99.8 25.25 0.028 0.835 adsorbate pseudo-second order model qe,exp(mg/g) qe,cal (mg/g) k2(g/mg min) r 2 cip 97.4 111.11 0.152 0.998 nor 93.3 100 0.149 0.998 levo 99.8 111.11 0.187 0.999 adsorbate interparticle diffusion model qe,exp(mg/g) c (mg/g) k3(mg/g min 1/2 ) r 2 cip 97.4 62.11 3.626 0.755 nor 93.3 57.59 3.726 0.757 levo 99.8 67.65 3.254 0.75 conclusions an activated carbon was prepared by using microwave method and k2co3 as activator and date stones as precursor. the prepared activated carbon showed an efficient adsorption of fluoroquinolones antibiotics with maximum percentage removal of 64.4, 62.0 and 65.7 % for cip, nor, and levo respectively. the experimental equilibrium adsorption data were described by lungmiur isotherm model with maximum adsorption capacity of 101.7, 99.71 and 104.76 mg/g for cip, nor, and levo respectively. the adsorption kinetic data are represented by pseudo-second order kinetic model. abbreviations cip ciprofloxcin levo levofloxcin nor norfloxcin nomenclature a equilibrium energy in temkin constant, l/mg b adsorption heat in temkin isotherm. c thickness of boundary layer in interparticle diffusion, mg/g ce equilibrium condentration of each antibiotics, mg/l c(t) concentration of each antibiotics at time t(min), mg/l initial concentration of each antibiotics, mg/l kf freundlich isotherm constant, (mg/g).(l/mg) 1/n kl lungmuir isotherm constant, l/mg k1 adsorption rate constant of pseudo-first order model, 1/min k2 rate constant of pseudo-second order model, mg/g.min k3 rate constant of interpartcle diffusion model, mg/g. min 1/2 qe uptake of antibiotic at equilibrium, mg/g ql maximum adsorption capacity, mg/g qt uptake of antibiotic at time t(min), mg/g v volume of antibiotic solutions, ml w weight of activated carbon, mg references 1scholar, m. e. "fluoroquinolines: past, present and future of a novel group of antibacterial agents" american journal of pharmaceutical education. 66: 164–172 (2002). 2sarkozy, g. "quinolones: a class of antimicrobial agents" veterinarni medicina. 46 (9–10): 257–274 (2001). 3queener, f. sh. "quinolone antibiotics" medical pharmacology. march: 14. (2002). 4lodha, r. s, roy, a. shah, sh. shah, d. vyas, b. kalyankar, g. joshi, sh. and koli, a. "fluoroquinolones": an overview, pharmaceutical reviews at adsorption of fluoroquinolones antibiotics on activated carbon by k2co3 with microwave assisted activation 22 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net pharmainfo website march; 6 (2). (2008). 5daifullah, a.a.m. girgis, b.s. gad, h.m.h. “u z residues (rice husk) in small waste w p ”, m letters 57 17231731. (2003) 6daifullah, a.a.m. girgis, b.s. “i p h activated carbon on adoption of ex,” d d s es a: 214 181 – 193. (2003) 7daifullah, a.a.m. girgis, b.s. "removal of some substituted phenols by activated carbon obtained from agricultural waste" wat. res., 32 (4), 11691177. (1998). 8sulyman, m. o. abudaia, j. a. alazabi, kh. y. "adsorption of co2 by activated carbon from date stones filled into a local design of automobile exhaust". gstf international journal of engineering technology (jet) vol.2 no.1, may (2013). 9josefa, j., m.a. pedro, v. gomezserrano, "oxidation of activated carbon by fry and wet methods: surface chemistry and textural modifications". fuel process technol., 91(11): 1768-1775. (2010). 10hui-hsin, t. w. ming-yen, "effects of acid treatments of activated carbon on its physiochemical structure as a support for copper oxide in de so2 reaction catalysts". chemosphere, 62(5): 756-766. (2006). 11ohkubo, t. yang, c.m. raymundo-pinero, e.s. kaneko, l.k. "high-temperature treatment effect of microporous carbon on ordered structure of confined so2". chem. phys. lett., 329 (1-2): 7175.( 2000) 12boudou, j.p. chehimi, m. broniek, e. siemieniewska, t. bimer, j. "adsorption of h2s or so2 on an activated carbon cloth modified by ammonia treatment. carbon" 41(10): 1999-2007. (2003). 13foo, k.y. hameed, b.h. "microwave-assisted preparation of oil palm fiber activated carbon for methylene blue adsorption". chem. eng. j., 166(2): 792-795. (2011). 14emine, y. meryem, o. aktas, z. "a novel method for production of activated carbon from waste tea by chemical activation with microwave energy". fuel, 87(15-16): 32783285. (2008). 15carrott, p.j.m. nabais, j.m.v. ribeiro carrott, m.m.l. menendez, j.a. "thermal treatments of activated carbon fibers using a microwave furnace" micropor. mesopor. mat., 47(2-3): 243-252. (2001). 16ji, y. li, t. zhu, l. wang, x. lin, q. "preparation of activated carbons by microwave heating koh activation" appl. surf. sci. 254 506-512. (2007). 17dureja, h. madan, a.k. "adsorption in pharmacy": a review, drug delivery technology; 7(8): 58-64. september (2007). 18viraraghavan, t, dronamraju, m.m. "removal of copper, nickel and zinc from wastewater by adsorption using peat". environmental science engineering 28:1262-1276. (1993). 19langmuir, i. "the adsorption of gases on plane surfaces of glass, mica and platinum", jacs 40 1361–1403. (1918) 20freundlich, h.m.f. "uber die adsorption in losungen". z phys chem 57; 385-470 (1906). 21langergen s. zur, b.k. "theorie der sogenannten adsorption geloester stoffe". veteruskapasakad handl 1898:24:1-39. 22weber, w.j. morris, j.c. "kinetics of adsorption on carbon from ammar s. abbas, muthana j. ahmed and teeba m. darweesh -available online at: www.iasj.net ijcpe vol.17 no.2 (june 2016) 23 solution j saint" eng div am soc civil eng: 89: 31-60.( 1963). 23haimour, n.m. emeish, s. "utilization of date stones for production of activated carbon using phosphoric acid" waste manage. 26 651–660. (2006) 24bamufleh, h.s. appl. catal. a: gen. 365 153–158. (2009). 25wang, c.j. li, z. jiang, w.t. "adsorption of ciprofloxin 0n 2:1 dioctahedral clay minerals". appl clay sci: 53: 969-72. (2011). 26zhang, c.l. qiao, g.l. zhoa, f. wang, y. "thermodynamic and kinetic parameters of ciprofloxin adsorption onto modified caol fly ash from aqueous solution". j mol liq: 163 :53-6. (2011) 27ahmed, m.j. theydan, s.k. "fluoroquinolones antibiotics adsorption onto microporous activated carbon from lignocellulosic biomass by microwave pyrolysis", journal of taiwan institute of chemical engineers 45 ;219-226. (2014). 28foo, k.y., hameed, b.h. "preparation of activated carbon by microwave heating of langsat (lansium domesticum) empty fruit bunch waste". bioresource technology 116; 522–525. (2012) 29sun y, yu, q. gao, b. huang, l. xu, x. li, q., "comparative study on characterization and adsorption properties of activated carbon with h3po4 and h4p2o2 activation employing cyperus alternifolins as precursor". chem eng j 181-182: 790-7. (2011) 30liu, w. zhang, j. zhang, c. ren, l. "sorption of norfloxacin by lotus stalk based activated carbon and iron-doped activated alumina; mechanisims, isotherms, and kinetics". chem eng j 171; 431-8. (2011). 31mahmoudi, k. hamdi, n. srasra, e. "preparation and characterization of activated carbon from date pits by chemical activation with zinc chloride for methyl orange adsorption" j. mater. environ. sci. 5 (6) ;1758-1769. (2014). 32el-kady, a.a. carleer, r. yperman, j. farah, j.y. "optimum conditions for adsorption of lindane by activated carbon derived from date stones" world applied sciences journal 27 (2): 269-279, (2013). 33carabineiro, s.a.c. thavornamornsri, t. pereira, m.f.r. serp, p. figneiredo, j.i. "adsorption of ciproflexin on surface modified carbon materials" water res 45:4583-4591.( 2011) available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.19 no.3 (september 2018) 19 – 31 issn: 1997-4884 corresponding authors: ayad a.alhaleem a.alrazzaq, email: ayadah65@yahoo.com, hasan ali neamah, email: haalieng86@gmail.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. torque and drag forces problems in highly deviated oil well hasan ali neamah and ayad a.alhaleem a.alrazzaq university of baghdad\college of engineering\petroleum engineering department abstract excessive torque and drag can be critical limitation during drilling highly deviated oil wells. using the modeling is regarded as an invaluable process to assist in well planning and to predict and prevent drilling problems. identify which problems lead to excessive torque and drag to prevent cost losses and equipment damage. proper modeling data is highly important for knowing and prediction hole problems may occur due to torque and drag and select the best method to avoid these problems related to well bore and drill string. in this study, torque and drag well plan program from landmark worldwide programming group (halliburton company) used to identify hole problems.one deviated well in zubair oil fields named, zb-250 selected for analyses the effect of friction factor on torque and effective `tension of the drill string along well depth, moreover the effect of well bore problems such as; mud lo sses, accumulation of cutting bed in the well bore, stuck pipe, caving, sloughing, high torque and drag values on drill string components and well trajectory. wells data which include hole section size, mud properties, well profile survey, casing string depth, rig specification, drill string components, drilling parameters like weight on bit, rotary speed and flow rate were used to compare between planning and drilling stages for these wells and identify the reasons of difference between these stages. the results showed a difference for the drilling phase and increasable in effective tension, torque, pick up and slack off drag, measured string weight, and possibility to occur the buckling if compare with planning phase. wellbore instability, high friction factor, high tortuosity, high flow rate ,stuck pipe , excessive drag spot, partial to total losses, increase of drilling parameters, hard formations and bad hole cleaning, all these factors yield to this difference between planning and actual phases. when drilling hole section 8.5", the main causes of varying were drilling fluid losses, high value of friction factor, stuck pipe and friction forces when the maximum torque was (16 to 20 klb-ft) and pick up weight (20-40 klb) keywords: torque, drag, stuck pipe, well bore instability received on 03/01/2018, accepted on 22/05/2018, published on 30l09l2018 https://www.doi.org/10.31699/ijcpe.2018.3.3 1introduction directional drilling represents a tool to reduce drilling operations costs of an oil field, due to two concerns; improve formation production when drill high deviated wells; hence, it can produce from low permeability zones better than vertical drilling, and the cost of rig operations and mobilization will be minimized because drilling more than well in the same land or platform. there are worldwide achievements of highly deviated drilling wells instead of vertical wells due to some challenge limitations. facility of reciprocating and rotating drill string in directional wells and large well bores area are two of the major concerns .in spite of drilling high deviated wells have many benefits, but still have limitations along drill deviated sections. the difficulties must be controlled by engineering activities. for examples getting optimum drilling parameters become more difficult in deeper wells especially with complicated well profile. two of these critical limitations called torque and drag that occur due to roughness between well bore in the cased or open hole and drill string ‎[1].torque and drag models have proven to be useful in all three stages of highly deviated wells: planning, drilling and post-analyses. while planning stage the models are used to optimize the well trajectory design to minimize torque, drag and contact forces between drill string and wellbore, during drilling phase it uses for monitoring of hole condition. torque and drag models are especially useful in diagnosing hole cleaning problems, impending differential sticking, and severe dogleg in addition to determine the possibility of reciprocating and movement casing and drill string during operation, in post-analyses phase the models help to determine the root causes of hole problems that previously were unexplained or attributed to other factors like mud density, mud chemical or shale problems ‎[2]. there are a number of causes for excessive torque and drag, like tight-spot condition, sloughing and swelling of shale, key seats, differential sticking, build-up of cutting caused by poor hole cleaning and well bore sliding friction. conversely, in wells with good hole conditions, the primary source of torque and drag is sliding friction ‎[3]. in highly deviated wells, solutions of torque and drag problems are essential to complete the drilling and completion operations because of many limitations are imposed by drilling rig, well path, drill string component, and drilling parameters, the engineering work have discovered methods to reduce torque and drag while drilling and tripping. https://www.doi.org/10.31699/ijcpe.2018.3.3 h. a. neamah and a. a. a.alrazzaq / iraqi journal of chemical and petroleum engineering19,3 (2018) 19-31 02 physical limitations effect how far a well can reach, especially in non-rotating operations such as slide drilling. if the compressive forces in the drill string are too high, pipe will buckle as a result from loss of weight transferred to the bit. if the rotary torque is too high, torsional failure will occur, or if the drag force is too high, the drilling string will become stuck or fail. therefore, it is essential for engineering to accurate account for the torque and drag forces and attempt to reduce them in order to prevent these scenarios from occurring ‎[4]. 1.1. problem statement the torque and drag are generated in the well bore during drilling. the miscalculated and misinterpreted of these parameters values will lead to time and money losses, because the special and expensive equipment and technology are involved in the drilling operations. the torque and drag magnitudes are required to be calculated for complete interval of the well bore as opposed to single depth torque magnitude, therefore these parameters are applying in the planned operations and updating the well bore trajectory in the next wells objectives. 1.2. the objectives of study this analyses study has been performed to get the following objectives: a. to be able to calculate and predict the frictional forces affecting the drill string and wellbore problems (torque and drag) by using well plan program from landmark programming group for this purpose in order to planned to keep the torque and drag forces at a minimum and with allowable limit and control this values while drilling highly deviated wells. b. to calculate the tension, pick up, slack off, minimum weight on bit and compression limits to prevent the buckling behavior belongs the drill string in order to get the opportunity before choosing the drill string components that consider these extra forces involved in the operations with high torque and drag values in deviated sections. c. to analyses the influence of well bore problem and high values of the torque and drag on planned and actual well trajectory in order to get the lesson learned to consider this consideration in the next planned well profile, as a result the well path must be design to reduce frictional forces and hole problems like; stuck pipe, mud losses, tortuosity and well bore instability. 1.3. significant and contribution of study a. to assist drilling oil field an engineer to make quick calculations for the torque and drag analysis while drilling directional and horizontal wells. b. to find the torque, drag, tension, compression, and buckling calculation during the well path design process that could prevent risks and problems before they happen. c. to get an idea for the drilling an engineer about torque and drag at any interval depth of the well bore section. 1.4. area of case study directional drilling performed in iraqi oil field about 2013 especially in zubair oil field. it is one of the largest oil fields in the world which located in the southern part of iraq; it was discovered in 1949 and went on stream in 1951. which located in 20 km southwest of basra city, the extension of zubair oil field is from south-west safwan passing near zubair city to al-hammar mishrif zone, the field is an anticline that runs roughly north-west to south-southeast approximately 60 km long and 10-15 km wide. this field consists of four domes from southeast into northeast as the following; safwan, rafidhyah shuaiba, and al-hammar. safwan dome extends to kuwaiti territory but it is in communication with the other domes of the zubair field through an aquifer. the zubair field includes three production reservoirs that have been appraised and produced; upper cretaceous mishrif limestone, lower cretaceous upper sandstone (3rd pay), and lower cretaceous lower sandstone (4th pay) ‎[5]. 1.5. review of previous work torque and drag modeling has been originally started with johancsick (1984) he assumed torque and drag to be caused by sliding friction forces that result from contact of wellbore with the drill string, and define this friction force to be a function of the normal contact force and the friction factor between contact surfaces based on coulomb's friction model. he wrote the force balance for an element of the pipe concerning that the normal component of tensile force acting on the element contributing to the normal force, this force is a different in case for a straight section like in hold section ‎[3]. the normal force is given by the following equation: √[( ) ( ) ] (1) where: : net normal force acting on element, [ ] : axial tension acting at lower end of element, [ ] : increase in inclination angle over length of element, [ ] : inclination angle at lower end of drill string element, [ ] : buoyed weight of drill string element, [ ] [ ] the above equation is then used to derive the tension increment tension which is used for drag calculations: = (2) : increase in tension over length of element [ ] : buoyed weight of drill string element, [ ] : sliding friction coefficient between drill string and well bore h. a. neamah and a. a. a.alrazzaq / iraqi journal of chemical and petroleum engineering19,3 (2018) 19-31 02 the plus and minus sign depends on pipe movement direction whether tripping in or pulling out of hole. and for the torsion increment which is used for torque calculations: (3) : increase in torsion over length of element [ ] = characteristic radius of drill string element [ ] aston (1998) addressed techniques to minimize torque and drag in the wellbore by mechanical and chemical methods. mechanical methods are like using special equipment or tubular in the wellbore to reduce torque and drag and chemicals methods are those which use lubricants ‎[6]. opeyemi et al. (1998) perform well planning and drill string design by using a torque and drag analysis with considering all constrains might be encountered while planning stage such as, surface location and target coordinates, geometric specification, casing program, geological obstacles. it also suggests that the torque and drag model which is used for planning and modeling processes must be updated with the dynamics of the field operation by performing drilling, tripping and frictional sensitivity analyses. this will ensure more precise and clearer understanding of drill string and well bore interactions from surface to total depth ‎[7]. rae et al.(2005) used torque and drag simulator to firstly plan a drilling well and then use it to calculate surface torque and hook load with the model has been used for planning after that comparing the values with surface hook load and torque field data. if they match this means that the well is drilling as it planned otherwise either a problem in the modeling or this is a warning sign of a problem in the well bore ‎[8]. schamp et al. (2006) suggested some industrial methods to reduced torque in the well bore while drilling. he explained two sources of torque in the wellbore: the frictional resistance between the drill string and casing or open hole and the bit/stabilizer torque and proposed some methods to mitigate the frictional resistance which containing enhancing drilling mud properties, using lubricants, adequate hole cleaning, promoting surface roughness and reducing side loads as much as possible by reducing the number of unnecessary dogleg or using rotary steerable system(rss) which gives a smother well path, applying a catenary well path if possible ‎[9]. mason et al. (2007) pointed out different major effects that should be considered in the soft string model. one of these factors is the drag force as a result of pipe movement in opposite direction of the drilling fluid flow. another effect is tortuosity. although the planned well is a smooth path, the crooked profile will be resulted in reality. for this reason the model has to take this factor into account. a crooked well profile shows higher torque and drag values. the buckling of the tubular should also be taken as a major factor in order to have a sense of excessive drag limit which may put the string in compression. aadnoy (2008) generalized the equations for different sections of the well bore and the status of the pipe either moving up or down to be applied simpler ‎[10]. mirhaj et. al. (2010) has analyzed a field case study that back-calculated the friction factor during drilling from field hook load and the result showed a friction factor of 0.05 for drilling interval while it was 0.2 for lowering and hoisting in that well. in this field, study also is in agreement with the angle and previous case study and a friction coefficient of 0.01 is needed to give a good match of the field and models data. the model used in this study by well plan program is soft-string model, in other words the drill string is assumed to be like a cable and forces due to bending moments have not been considered to affect the normal forces and thus friction. this is fairly good assumption as it may contribute small normal forces on the overall force balance ‎[2]. 2research methodology well plan program can define as drilling operation, completion activities, and production service operations engineering programing. its might be used at the office engineering work and well site activity to provide a tool for solving problems between engineering functions and oil field operations. it is based on a database and data structure common to many of landmark’s drilling applications. this database is called the engineer’s drilling data model (edm) and supports the different levels of data that required using the drilling software. the significant advantage while using the software because of improved integration between drilling software products,currently, well plan, compass, stress check, casing seat, well cat, and casing wear software use the common data base and data structure. the competitive environment companies are facing increasing numbers of technician difficulties such as; deep wells drilling, extended-drilling wells, thinhole drilling, underbalanced drilling operations, and environmentally effect of drilling zones ‎[11]. the results from using well plan that offers more efficient analysis using only necessary inputs, saving time, and minimizing analysis steps. well plan is integrated with the other engineering data training (edt) applications enabling you to install it on the same computer or server in multi-user environments, and share data with other edt software applications. the torque and drag options represent one from well plan application can be used to calculate and predict effective tension weights, buckling limit, allowable pick up and slack off forces, minimum wob can exerted without get buckling, over pull margin, drill string analyses, and torque that can be phases while the operating conditions[12]; running in the hole, pulling out of the hole, rotating on bottom, rotating off bottom h. a. neamah and a. a. a.alrazzaq / iraqi journal of chemical and petroleum engineering19,3 (2018) 19-31 00 while pulling out of the hole, slide drilling without rotary table rotation , and back reaming after drilling. the construction of well plan model which includes the input data as follows: 1datum information for a land well: as shown in fig. 1 the datum information for well zb-250. fig. 1. datum information for well zb-250 2fluids editor type: data entry that is used to define drilling fluid properties such as; mud based type, rheology model, density, viscosity, and yield point, as shown in fig. 2. fig. 2. mud properties for well zb-250 3rig information: the rig tab is used to define mechanical limits information, including rig hoisting capacity and rotary torque rating. furthermore, circulating system information including rated working pressure for surface equipment, blow out preventer (bop), pressure rating, surface pressure loss, mud pit, and mud pumps specification, as shown in fig. 3. fig. 3. rig capacity for well zb-250 4hole section editor: hole section editor tab to input the riser, casings and liner, open hole sections, friction factors for cased and open hole sections, as shown in fig. 4. fig. 4. casing information for well zb-250 h. a. neamah and a. a. a.alrazzaq / iraqi journal of chemical and petroleum engineering19,3 (2018) 19-31 02 5operation editor:the operations tab is used to define the operations that appear on various outputs with the parameters needed to generate that output. as shown in fig. 5, output normal analysis select the analysis type and enter the parameters to be used in the analysis. the options available are tripping in, tripping out, and rotating on bottom, slide drilling, back reaming, and rotating off bottom. fig. 5. operation parameters for zb-250 6drill string components: the string tab accesses the string editor that is used to define the drill string component details such as, length, size, weight, makeup torque, minimum yield strength , over pull margin, and depth of bha, furthermore the length, size, weight, grade , make-up torque, minimum yield strength, and depth of drill pipe, additionally; this details are defined on this panel, as shown in fig. 6. and the table 1 fig. 6. drill string components for zb-250 table 1. drill string components configuration for well zb-250 ‎[13] field name eni_zubair borehole name zb-250(saf-hor) pilot hole hole size (in) 8.500 structure name zb-250(saf-hor)well bha name 8.5in rotary bha with mwd -130214 depth in (m) 3051.00 well name zb-250(saf-hor)well depth out (m) 3216.00 desc. manu. od (in) max od (in) bot size (in) bot type bot gender length (m) cum. length (m) cum. weight (t) id (in) top size (in) top type top gender 1 8 1/2 " pdc bit smith international 5.750 8.500 0.25 0.25 0.0 2.250 4.500 regular pin 2 8.25nb stabilizer 6.750 8.250 4.500 reg box 1.52 1.77 0.3 2.500 4.500 nc50 (4 1/2 if) box 3 float sub 6.500 6.500 4.500 nc50 (4 1/2 if) pin 1.52 3.30 0.5 2.813 4.500 nc50 (4 1/2 if) box 4 nmdc 6.750 6.750 4.500 nc50 (4 1/2 if) pin 9.14 12.44 2.0 2.250 4.500 nc50 (4 1/2 if) box 5 telescope 675 nf schlumberger 6.750 6.890 4.500 nc50 (4 1/2 if) pin 7.53 19.97 2.9 5.109 4.500 nc50 (4 1/2 if) box 6 nmdc 6.750 6.750 4.500 nc50 (4 1/2 if) pin 9.14 29.11 4.4 2.250 4.500 nc50 (4 1/2 if) box 7 8.5 stabilizer 6.750 8.250 4.500 nc50 (4 1/2 if) pin 1.52 30.64 4.6 2.813 4.500 nc50 (4 1/2 if box 8 6.5" collar 6.500 6.500 4.500 nc50 (4 1/2 if) pin 9.14 39.78 6.0 2.810 4.500 nc50 (4 1/2 if) box 9 heavy weight drill pipe (2 joints) 5.000 6.500 4.500 nc50 (4 1/2 if) pin 19.70 59.48 7.4 3.000 4.500 nc50 (4 1/2 if) box 10 jar smith 6.500 6.500 4.500 nc50 (4 1/2 if) pin 6.86 66.34 8.5 2.810 4.500 nc50 (4 1/2 if) box 11 heavy weight drill pipe (13 joints) 5.000 6.500 4.500 nc50 (4 1/2 if) pin 130.00 196.34 18.2 3.000 4.500 nc50 (4 1/2 if) box 12 5" dp (302 joints) 5.000 6.625 4.500 nc50 (4 1/2 if) pin 3020.00 3216.34 145.5 4.000 4.500 nc50 (4 1/2 if) box h. a. neamah and a. a. a.alrazzaq / iraqi journal of chemical and petroleum engineering19,3 (2018) 19-31 02 7well path: vertical section, survey data imports and tortuosity are defined on the well path tab. it can be entered well path data points directly, measured depth values (md), inclination (inc), and azimuth (az) must be entered for each depth, as shown in fig. 7. other common well path information is calculated automatically, it can be viewed using the well path table, as shown in the table 2. fig. 7. well path information for zb-250 table 2. well path details for well zb-250 md inc azi tvd dls abstort reltort vsect north east build walk (ft) (°) (°) (ft) (°/100ft) (°/100ft) (°/100ft) (ft) (ft) (ft) (°/100ft) (°/100ft) 0 0 0 0 0 0 0 0 0 0 0 0 98.4 0.08 172.73 98.4 0.08 0.08 0 -0.1 -0.1 0 0.08 0 196.9 0.07 194.7 196.9 0.03 0.06 0 -0.2 -0.2 0 -0.01 22.32 295.3 0.04 136.88 295.3 0.06 0.06 0 -0.3 -0.3 0 -0.03 -58.75 393.7 0.1 143.54 393.7 0.06 0.06 0 -0.4 -0.4 0.1 0.06 6.77 492.1 0.11 181.16 492.1 0.07 0.06 0 -0.5 -0.5 0.1 0.01 38.22 590.6 0.02 239.22 590.6 0.1 0.07 0 -0.6 -0.6 0.1 -0.09 58.99 689 0.12 103.58 689 0.14 0.08 0 -0.7 -0.7 00ii.2 0.1 -137.81 787.4 0.19 80.77 787.4 0.09 0.08 0 -0.7 -0.7 0.5 0.07 -23.17 885.8 0.21 68.3 885.8 0.05 0.08 0 -0.6 -0.6 0.8 0.02 -12.67 984.3 0.28 64.19 984.2 0.07 0.08 0 -0.4 -0.4 1.2 0.07 -4.18 1,082.70 0.19 84.39 1,082.70 0.12 0.08 0 -0.3 -0.3 1.6 -0.09 20.52 1,181.10 0.14 77.85 1,181.10 0.05 0.08 0 -0.2 -0.2 1.8 -0.05 -6.64 1,279.50 0.19 78.3 1,279.50 0.05 0.08 0 -0.2 -0.2 2.1 0.05 0.46 8analyses setting ‎[11]: analysis settings tab can be used to configure the analysis parameters settings pertaining to the outputs, only the analysis settings or options required for the selected outputs are displayed on this tab. if the parameters are not required for the displayed plot, the section will not be visible. the settings are divided into many groups, common analysis options are not specific to one type of analysis (torque and drag, hydraulics), for example, the pump rate specified will be used for any torque and drag or hydraulics, other analyses options available are torque and drag, it can be used torque and drag parameters to specify analysis options outputs currently have in the output area. two of the common setting are necessary especially in torque and drag analyses setting, as shown in fig. 8, operational pump rate and run parameters. these options allow specifying the depth of the bottom of the string at numerous intervals along the wellbore for the purpose of analysis. these depths are used to generate output for four torque and drag plots like; effective tension and compression with buckling limit, torque plot along well depth, drill string analyses (include minimum wob, allowable pick up and slack off weight, and over pull margin), and well path with tortuosity. fig. 8. analyses setting parameters for well zb-250 h. a. neamah and a. a. a.alrazzaq / iraqi journal of chemical and petroleum engineering19,3 (2018) 19-31 02 9output data: a listing of outputs for torque and drag analysis, use torque & drag tab to access plots and tables for torque and drag analysis. these plots can show and calculate the possibility of drilling the well, in addition to indicate what the challenges while drilling the well will occur. drill strings, casing strings, and liners can be analyzed, as shown in fig. 9 that shows all torque and drag output plots available can be determine by well plan program. fig. 9. all torque and drag output available in well plan software ‎[11] appendixa which gives the summary configuration for the well plan entering data steps and the output which used in this study, as called well plan flow chart. 3results and discussion in order to analyses the results that resulted from well plan model and study the effect of the friction factor, well path, drill string component on well bore problems, three wells data are examined, namely, zb-250, this deviated oil well were drilled in zubair oil field with different hole problems during drilling operations such as; accumulation of cutting bed, pipe sticking, mud losses, tortuosity and well bore instability, then discuss the effect of these problems on drill string tension and compression, torque and drag behavior, well path with tortuosity, and drill string behavior. all the input data for well zb-250 in this study, such as; well path survey, bha details, hole sections, casing string setting depth, drilling fluid properties, and drilling parameters for well planning stage were got from drilling and geological program that prepared by the operator company zubair field operation division (zfod) and service companies like halliburton and schlumberger. furthermore the wells data for drilling phase, were got from final well report that prepared by zubair field operation division (zfod) after complete drilling operations for this well. in this chapter a discussion of the output plots such as; effective tension and compression with buckling limit, torque value with different friction factor, the well path inclination with tortuosity and drilling time curve, drill string analyses include minimum wob to prevent buckling, allowable pick up and slack off weight, and over pull margin for three wells that result from torque and drag model to be calculated and then performed study and analyses the hole problem effect on these parameters in planning and drilling phases. 3.1. well zb-250 the well zb-250 is planned as a horizontal well, it is a part of development plan in zubair oil field, its objective to develop and produce oil from upper cretaceous zubair sandstone reservoirs (3rd pay). the spud date for this well was performed on 10th november 2013, and the date which complete the drilling activity and reached to total depth (td) was implemented on 18th february 2014 ‎[14]. the first hole section 23" was drilled with only one bit smith type and spud mud through the following formations, dibdibba , lower fars, ghar and 4m inside dammam formation and the depth for this section was 509 m. the second hole section 17.5" was drilled to 1776 m through the following formation, dammam, rus, ummer-radhuma, tayarat, shiranish, hartha and 4m inside saadi formation. the third hole section 12 1/4" was drilled with one bit with kcl/polymer mud through the following formations, saadi, tanuma, khasib, mishrif, rumaila, ahmadi, mauddud, nahr umr to depth 3060m ‎[14]. the objective for this well is the drilling 8 1/2" hole section with salt-polymer mud through nahr umr, shuaiba, upper shale formations and performed blind drilling (without mud returns) vuggy limestone shuaiba formation through potential loss zone of formation with directional bottom hole assembly (bha),because in case of total losses the exposure of the stuck pipe will minimize when used directional bha, and effectively cure losses by pumping losses cure material (lcm) through the bit. the hole section8 1/2" drilled from 3060m to 3228m, while drilling this section observation of mud losses varied to (2 m 3 / hr to total losses) and observed high torque value (15 klb-ft), furthermore high over pull (35 ton) while trying to pull out the drill string back to the casing shoe and pump losses cure material(lcm) to cure the losses ‎[14]. at depth 3110m observed drill string stuck, high torque, hard reaming, the total losses, and rotation stopped while try to pick up the string immediately to casing shoe to pumping lcm, then try to make drill string free by jarring and (25 ton over pull) and slack off 10 tons, combine with rotate at 50 rpm, string went up gradually and get free at 3104 m. finally, due to the total loss problem from 3108m to 3228m and tried to cure it with pumping lcm , different types of cement plugs and ran rotary slick bha, no success to cure losses zone, decided to set cement plug to temporary abandon for this well, as shown in fig. 10 well zb-250 profile ‎[14]. h. a. neamah and a. a. a.alrazzaq / iraqi journal of chemical and petroleum engineering19,3 (2018) 19-31 02 the following figures (10 to 22) show the following output data (effective tension and torque value with different friction factor, well path inclination with tortuosity and drill string analyses include minimum wob to prevent buckling, allowable pick up and slack off, over pull margin and drilling time curve) for planning and drilling phases for well zb-250. fig. 10. well zb-250 profile ‎[14] fig. 11. effective tension with md, well zb-250, ff ch/oh 0.25/0.3-planning fig. 12. effective tension with md, well zb-250, ff ch/oh 0.25/0.4,planning fig. 13. effective tension with md, well zb-250, ff ch/oh 0.3/0.35drilling the figs.(11 to 13) show the effective tension and compression in the drill string for the operations conditions available in the well plan program (tripping in, tripping out, rotating on bottom, slide drilling, back reaming, and rotating off bottom) with measured depth from surface to drill string depth. furthermore these figures indicating the loads required to helically or sinusoidally buckle the drill string. if an operation curve crosses a buckling load curve, the string will begin to buckle in the buckling mode corresponding to the buckling load line. these plots show that the tripping out and back reaming conditions effective tension is greater than the other operation conditions because of the direction of the drill string movement for them against the gravity forces, as a h. a. neamah and a. a. a.alrazzaq / iraqi journal of chemical and petroleum engineering19,3 (2018) 19-31 02 result will get additional tension force added to drill string weight if compare with tripping in condition for same drill string components. the effective tension increase when friction factor (ff) increase and found the negative effect for this increasable on slide drilling condition and buckling behavior (sinusoidal and helical) from depth (7000 to 10000 ft) will occur when used friction factor 0.4 for open hole, as shown in fig. 12 for planning phase, so it is not recommended to use this value of the friction factor to prevent drill string buckling. the effective tension for drilling phase, as shown in fig. 13 when ff 0.35 for open hole (back reaming operating mode) is greater than the planning phase when ff 0.4 because of stuck pipe behavior, hard back reaming and high over pull observed while try to pulling out the drill string inside 9 5/8" casing shoe. the compression of the drill string can be found in previous figures as a negative values during tripping in, rotating on bottom, and slide drilling due to axial load exerted on the drill string in these conditions, further more can be noticed this axial load decreased when reached to horizontal section in planning phase, as shown in fig. 11 and fig. 12 because of the drill string in the horizontal section embedded on low side of the well bore, as a result for this behavior the wob will decrease and compression will reduce. in the drilling case not reached to horizontal section due to abandon the well before complete the drilling, so cannot found this behavior, as shown in fig. 13. fig. 14. torque with md, well zb-250, ff ch/oh 0.25/0.3, planning fig. 15. torque with md, well zb-250, ff ch/oh 0.25/0.4, planning fig. 16. torque with md, well zb-250 , ff ch/oh 0.3/0.35, drilling. figs. (14 to 16) show that the torque in the drill string for the operation conditions corresponding to the measured depth from the surface to the string depth (8.5" hole section). from these figures can be noticed the highest torque values in the surface and start decrease gradually until reach to the minimum values as called torque on bit, furthermore can be found the torque for drilling on bottom and back reaming conditions increase when ff increased. fig. 16 shows the torque for drilling on bottom and back reaming condition for drilling phase ff 0.35 (open hole) are greater than the same conditions with higher ff = 0.4 (open hole) as shown in fig. 15, especially in the h. a. neamah and a. a. a.alrazzaq / iraqi journal of chemical and petroleum engineering19,3 (2018) 19-31 02 deviated section after 9 5/8 casing shoe, because of high torque , hard back reaming and high value of over pull due to stuck pipe behavior ( no movement, no rotation), high tortuosity and irregular well bore shape, and total mud losses , all these factors caused hard stuck pipe that lead to high torque in the deviated hole section 8.5". another two factors effect leaded to high value of torque in the drilling phase as compare with planning phase were built of cutting in the annulus and well bore caving in the deviated section can be indicated that on the shape of cutting on shale shaker as mentioned in the final well report [14]. fig. 17. drill string analyses, ff ch/oh 0.25/0.3 – planning fig. 18. drill string analyses, ff ch/oh 0.25/0.4 – planning fig. 19. drill string analyses, ff ch/oh 0.3/0.35 – drilling figs. (17 to 19) show the drill string behavior for selected operating mode, it’s include load and stress data, any failures due to stress (fatigue, over maximum yield strength of drill string component), buckling (sinusoidal or helical), and torque failure are indicated depend on data entering to the model. minimum wob while rotating must be not exceeded to prevent buckling and its depth can be found in the previous tables, furthermore allowable (safe) pick up and slack off weight in case of high drag zone and over pull margin within safe operating condition to prevent any drill string failure corresponding to 90% from drill string component minimum yield strength. as shown in these figures when friction factor increased the measured weight of the drill string will increased as a result from increasable of contact force between drill string and well bore especially in the slide drilling ,back reaming, and tripping out conditions. as shown in fig. 18 the slide drilling mode can result buckling behavior (sinusoidal and helical) with ff = 0.4 (open hole) for planning stage and this indicate more certainly as mentioned before and shown in fig. 12 for effective tension curve which cross buckling limit curve. h. a. neamah and a. a. a.alrazzaq / iraqi journal of chemical and petroleum engineering19,3 (2018) 19-31 02 fig. 20. well path inclination with md,zb-250, planning fig. 21. well path inclination with md,zb-250,drilling fig. 22. drilling time curve, zb-250, drilling [14] figs. (20 and 21) show the inclination angle at any depth in the wellbore with tortuosity of the well path for planning and drilling phases depending on well path input data, it can be noticed the inclination angle for planning stage was about 88 degree, but in the drilling phase becomes 42 degree because of abandon the well due to total losses problem and difficulty to cure it.as shown in fig. 21, for actual drilling days. furthermore, it can be showed more tortuosity and deviation from planning survey due to well bore instability and implement sidetrack operation at that time, as a result stuck pipe problem, side track operation, and try to cure mud losses, the extra days was needed for these operation as shown in the fig. 22, the difference between planning and actual days. 4conclusions 1the study of torque and drag by landmark programming group showed that the friction factor had a highly effect on the friction forces of the drill string and well path. 2the results show the effect of the following parameters: [1.tension and compression, 2. torque, 3. drill string analyses include minimum wob to avoid buckling types, 4. allowable pick up and slack off weight, 5. over pull margin] on the drill string component that caused increase the frictional forces [torque and drag] due to the hole problems. 3the results show that the effect of well bore problem on well trajectory target such as; [mud losses, stuck pipe, well bore instability, shale problems, high torque and drag spots, caused different well path in comparison with planning well path. these problems increased the tortuosity and non-productive time (npt). moreover the results indicated the main causes of differences for frictional forces in the planning and actual drilling depend on friction factor and hazards for hole drilling section 8.5", the main causes of varying were drilling fluid losses, high value of friction factor, stuck pipe and friction forces when the maximum torque was (16 to 20 klb-ft) and pick up weight (20-40 klb). acknowledgments i wish to express my appreciation and thanks to mr. osama alamede, member in the petroleum engineering department for his help, guidance, encouragement and facilitation to provided well plan software from landmark group. i am truly grateful to mr. ahmed moayed, landmark country manager for this help to get well plan software from landmark customer support (halliburton company), ideas, advice and assistance during the preparation of this work. great thanks and appreciation to the trouble shouting and technician in landmark customer support, ahmed saad for this help, advise to fix some technical problems in well plan software during this work. h. a. neamah and a. a. a.alrazzaq / iraqi journal of chemical and petroleum engineering19,3 (2018) 19-31 22 may many thanks and appreciation to mr. jawad kadhim, zfod drilling supervisor for providing the data and information required for accomplishment of this work. abbreviations bha: bottom hole assymbly bop: blow out preventer ch: cased hole edm: engineering data model edt: engineering data training klb: kilo bound lcm: losses cure material md: measured depth npt: nonproductive time oh: open hole rpm: revolution per minute wob: weight on bit nomenclature ft axial tension acting at lower end of element, [ ] increase in inclination angle over length of element, [ ] inclination angle at lower end of drill string element, [ ] buoyed weight of drill string element, [ ] ∆ft increase in tension over length of element ibf [n] buoyed weight of drill string element, ibf [n] sliding friction coefficient between drill string and well bore increase in torsion over length of element [ ] characteristic radius of drill string element [ ] references [1] burak kağan çağlayan "torque and drag applications for deviated and horizontal wells :a case study", a thesis submitted to the graduate of natural and applied science of middle east technical university, december 2014. [2] mirhaj s.a., fazaelizadeh m., kaarstad e., aadnoy b.s., "new aspects of torque-and-drag modeling in extended-reach wells," 2010 spe/135719 annual technical conference and exhibition, florence, italy, 19-22 september 2010. [3] johancsik, c.a., friesen, d.b.,dawson, r. "torque and drag in directional wells – prediction and measurement". journal of petroleum technology, june 1984. [4] mccormick j.e., evans c.d., le j., chiu t., "the practice and evolution of torque and drag reduction: theory and field results, "international petroleum technology conference (iptc 14863), thailand, 7-9 february 2012. [5] geoservices, a schlumberger company "final drilling and geological report for well zb-250", unpublished report, zubair field operation division, november to march 2014. [6] aston m.s., hearn p.j., mcghee g., "techniques for solving torque and drag problems in today's drilling environment," 1998 spe annual technical conference and exhibition held in new orleans, louisiana,27-30 september 1998, spe 48939. [7] opeyemi, a. a. and pham, s.v., "a robust torque and drag analysis approach for well planning and drill string design", spe/iadc 39321 presented at spe/iadc drilling conference, dallas, texas, march 1998. [8] rae, g., lesso., w.g., sapijanskas, m., "understanding torque and drag: best practices and lessons learnt from the captain field’s extended reach wells", spe/iadc 91854 presented at the spe/iadc drilling conference, amsterdam, netherlands, february 2005. [9] schamp, j. h., estes, b. l. and keller, s. r., "torque reduction techniques in erd wells" spe/iadc 98969 presented at the spe/iadc drilling conference, miami, florida, february 2006. [10] mason,c. j. and chen, d. c.,"step changes needed to modernize torque and drag software", spe/iadc 104609 presented at the 2007 spe/iadc drilling conference, amsterdam, netherlands,february 2007. [11] landmark software operates technical assistance centers,http://css.lgc.com/infocenter/index?page=contac t&sectio n=contact, halliburton 2016. [12] mirhaj seyed ahmad, kaarstad eirik, aadnoy bernt s., "improvement of torque-and-drag modeling in long-reach wells",petroleum engineering department, university of stavanger, september 2011 [13] zubair field operation division (zfod), schlumberger, "geological and drilling program zb250, unpublished, issued: 21st december, 2013. [14] zubair field operation division (zfod), schlumberger, "geological and drilling final well report for zb-250 (saf-hor), unpublished, february 2014. appendix a http://etd.lib.metu.edu.tr/upload/12618227/index.pdf http://etd.lib.metu.edu.tr/upload/12618227/index.pdf http://etd.lib.metu.edu.tr/upload/12618227/index.pdf http://etd.lib.metu.edu.tr/upload/12618227/index.pdf http://etd.lib.metu.edu.tr/upload/12618227/index.pdf https://www.onepetro.org/conference-paper/spe-135719-ms https://www.onepetro.org/conference-paper/spe-135719-ms https://www.onepetro.org/conference-paper/spe-135719-ms https://www.onepetro.org/conference-paper/spe-135719-ms https://www.onepetro.org/conference-paper/spe-135719-ms https://www.onepetro.org/journal-paper/spe-11380-pa https://www.onepetro.org/journal-paper/spe-11380-pa https://www.onepetro.org/journal-paper/spe-11380-pa https://www.onepetro.org/journal-paper/spe-11380-pa https://www.onepetro.org/conference-paper/iptc-14863-ms https://www.onepetro.org/conference-paper/iptc-14863-ms https://www.onepetro.org/conference-paper/iptc-14863-ms https://www.onepetro.org/conference-paper/iptc-14863-ms https://www.onepetro.org/conference-paper/iptc-14863-ms https://www.onepetro.org/conference-paper/spe-48939-ms https://www.onepetro.org/conference-paper/spe-48939-ms https://www.onepetro.org/conference-paper/spe-48939-ms https://www.onepetro.org/conference-paper/spe-48939-ms https://www.onepetro.org/conference-paper/spe-48939-ms https://www.onepetro.org/conference-paper/spe-39321-ms https://www.onepetro.org/conference-paper/spe-39321-ms https://www.onepetro.org/conference-paper/spe-39321-ms https://www.onepetro.org/conference-paper/spe-39321-ms https://www.onepetro.org/conference-paper/spe-39321-ms https://www.onepetro.org/conference-paper/spe-91854-ms https://www.onepetro.org/conference-paper/spe-91854-ms https://www.onepetro.org/conference-paper/spe-91854-ms https://www.onepetro.org/conference-paper/spe-91854-ms https://www.onepetro.org/conference-paper/spe-91854-ms https://www.onepetro.org/conference-paper/spe-98969-ms https://www.onepetro.org/conference-paper/spe-98969-ms https://www.onepetro.org/conference-paper/spe-98969-ms https://www.onepetro.org/conference-paper/spe-98969-ms https://www.onepetro.org/journal-paper/spe-0208-0045-jpt https://www.onepetro.org/journal-paper/spe-0208-0045-jpt https://www.onepetro.org/journal-paper/spe-0208-0045-jpt https://www.onepetro.org/journal-paper/spe-0208-0045-jpt https://www.onepetro.org/journal-paper/spe-0208-0045-jpt http://css.lgc.com/infocenter/index?page=contact&sectio http://css.lgc.com/infocenter/index?page=contact&sectio h. a. neamah and a. a. a.alrazzaq / iraqi journal of chemical and petroleum engineering19,3 (2018) 19-31 22 مشاكل قوى عزم الدوران والسحب في االبار النفطية شديدة الميالن الخالصة العزم والسحب الزائد من المحددات الحرجة اثناء حفر االبار شدٌدة المٌالن. استخدام النموذج ٌعد عملٌة ذات عالوة على ذلك تشخٌص اي من مشاكل البئر قٌمة للمساعدة فً تخطٌط البئر والتنبؤ لتجنب مشاكل الحفر. . استخدام بٌانات النموذج المناسبة تؤدي الى العزم والسحب العالً لتجنب خسارة االموال وتضررالمعدات مهمة جدا لمعرفة وتنبؤ مشاكل البئر التً تحدث نتٌجة العزم والسحب واختٌار الطرٌقة االفضل لتجنب هذه المشاكل بالنسبة لمقطع البئر وخٌط الحفر.فً هذه الدراسة برنامج تخطٌط البئر الخاص بالعزم والسحب من مجٌات )شركة هالٌبرتون( استخدم لتشخٌص مشاكل البئر.بئر مائلة فً حقل مجموعة الندمارك العالمٌة للبر اختٌرت لتحلٌل تأثٌر معامل االحتكاك على العزم والشد المؤثر لخٌط الحفر 022 -زبٌر -باسم النفطً الزبٌر ت تجمع قطع الفتا ،عالوة على ذلك تأثٌر مشاكل مقطع البئر مثل فقدان سائل الحفر،خالل عمق البئر التكهف واالنسالخ لجدار البئر اضافة الى قٌم العزم الدورانً ،استعصاء االنابٌب ،الصخري فً مقطع البئر والسحب العالٌٌن على مكونات خٌط الحفر ومسار البئر. بٌانات البئرالتً تشمل حجم مقطع البئر, مواصفات طٌن الحفر,مسح مقطع البئر,عمق انابٌب لحفر,مكونات خٌط الحفر,معامالت الحفر مثل الوزن على البرٌمة ,سرعة الدوران و البطانة,مواصفات جهاز ا معدل التدفق استخدمت للمقارنة بٌن حالتً التخطٌط والحفر الفعلً لهذه االبار وتحدٌد اسباب االختالف بٌن المرحلتٌن. عزم الدورانً والسحب لالعلى اظهرت النتائج اختالفا فً مرحلة الحفر اي زٌادة فً الشد الفعلً وكذلك فً ال واالسفل ووزن عمود الحفر المقاس واحتمالٌة حدوث التواء لخٌط الحفر اذا ماقورنت مع مرحلة التخطٌط. عدم استقرارٌة مقطع البئر,معامل االحتكاك العالً,التعرج العالً للبئر,معدل التدفق العالً,استعصاء ً والكلً,الزٌادة فً متغٌرات الحفر,الطبقات الصلبة والتنظٌف االنابٌب,مناطق السحب الزائد,الفقدان الجزئ غٌر الجٌد للبئر.كل هذه الغوامل تؤدي الى هذا الفرق بٌن المخطط له والحالة الحقٌقٌة. انج كانت االسباب الرئٌسٌة لهذا االختالف هو فقدان سائل الحفر,معامل االحتكاك 2.2عند حفر مقطع البئر قدم –( كٌلو باوند 02-22االنابٌب وقوى االحتكاك حٌث ان اعلى عزم دورانً هو بٌن )العالً,استعصاء ( كٌلو باوند.22 – 02ووزن السحب لالعلى بٌن ) iraqi journal of chemical and petroleum engineering vol.17 no.2 (june 2016) 16 issn: 1997-4884 experimental study of thermophysical properties of tio2 nanofluid majid i. abdulwahab * , s.m.thahab ** and asmaa h.dhiaa *** * chemical engineering department, university of baghdad, baghdad, iraq, e-mail: majid58jc@yahoo.co.uk ** nanotechnology and advanced materials research unit (namru), college of engineering – university of kufa – 21 najafiraq; e-mail: sabah.alabboodi@uokufa.edu.iq *** materials engineering department s college of engineering – university of kufa – 21 najafiraq ce_asmaa@yahoo.com abstract titanium-dioxide (tio2) nanoparticles suspended in water, and ethanol based fluids have been prepared using one step method and characterized by scanning electron microscopy (sem), and uv–visible spectrophotometer. the tio2 nanoparticles were added to base fluids with different volume concentrations from 0.1% to1.5% by dispersing the synthesized nanoparticles in deionized water and ethanol solutions. the effective thermal conductivity, viscosity and ph of prepared nanofluids at different temperatures from 15 to 30 o c were carried out and investigated. it was observed that the thermal conductivity, ph, and viscosity of nanofluids increases with the increase in tio2 nanoparticle volume fraction. the thermal conductivity of tio2 nanofluids significantly increases linearly with increasing particle vol. fraction at different temperature values and also it was found that the viscosity increases with increasing particle vol. fraction and decreases with the increase in temperature. key words: nanofluids, thermal conductivity, viscosity, tio2 nanoparticles. introduction nanofluids are engineered by suspending nanoparticles with common sizes below 100 nm in conventional heat transfer fluids such as water, oil, and ethylene glycol. improvements in the thermal properties of base fluids, was indicated when an extremely small amount of nanoparticles dispersed regularly and suspended stably in base fluids. nanofluid is the term introduced by choi [1] to express this novel class of nanotechnology-based heat transfer fluids that exhibit thermal properties better than those of their host fluids or conventional particle fluid suspensions. titanium-dioxide (tio2) is one of the most paying attention materials in nanoscience and nanotechnology because of having a lot of attractive properties from fundamental and practical point of view by castillo et al. [2]. titanium-dioxide is present in three crystal forms: rutile, anatase and brookite; where the rutile and anatase phases have higher practical utility. iraqi journal of chemical and petroleum engineering university of baghdad college of engineering mailto:majid58jc@yahoo.co.uk mailto:sabah.alabboodi@uokufa.edu.iq mailto:ce_asmaa@yahoo.com experimental study of thermophysical properties of tio2 nanofluid 2 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net yoo et al. [3] showed that the presence of nanoparticles of tio2, al2o3, and fe in base fluid caused a large enhancement in thermal conductivity compared to their base fluid. kim et al. [4] have calculated the thermal conductivity of zno and tio2 nanoparticals in base fluid (water and ethylene glycol). the experimental data showed the effects of both particle size and volume concentration on thermal conductivity. in the present study the thermophysical properties of tio2 nanoparticles in base fluids of deionized water and ethanol in the temperature ranges of 15-30 o c at different volume concentrations of nanoparticles (0.1, 0.5,1 and 1.5%) was investigated. experimental 1preparation of nanofluids titanium dioxide nanoparticles, anatase, with an average diameter of 13 nm were used in the present work (ordered form usa nanomaterials co.) [5]. tio2 nanoparticles with different volume concentrations (0. 1%, 0.5%, 1%, 1.5%) were dispersed in ddw (denoized water) and ethanol based fluids. the suspensions of nanofluids were then stirred and agitated thoroughly for 15 min with an ultrasonic homogenizer. this ensures uniform dispersion of nanoparticles in the base fluid. table 1 shows the physical properties of tio2 nanoparticles. table 1, properties of tio2 nanoparticle average particle diameter, nm 13 purity, % 99.99 density, kg/m 3 3900 color white 2thermophysical properties and characterization of tio2 based nanofluids thermal conductivity was measured using a thermal conductivity meter (kd2 pro, decagon device, usa). a viscometer (fungilab) was used for viscosity measurement. ph was measured using a pocket-sized ph meter with replaceable electrode (inolabph7110), tio2 nanopaticles were characterized by using sem model (fei). uv-visible (model uvwin5 spectrophotometer) was used to show the absorption spectroscopy or reflectance spectroscopy in the ultraviolet-visible spectral region. fig. (1) shows the sem micrograph of the tio2 nanoparticles. the micrograph shows that the particles have nearly spherical shape and uniformly distributed. larger particles may be aggregates of the smaller ones. fig. 1, sem morphology of tio2 nps the energy dispersive x-ray analysis (edx) image of the tio2 nanoparticles was recorded in the binding energy region of 0–20 kev as shown in fig. (2). http://en.wikipedia.org/wiki/absorption_spectroscopy http://en.wikipedia.org/wiki/absorption_spectroscopy http://en.wikipedia.org/wiki/ultraviolet http://en.wikipedia.org/wiki/visible_spectrum majid i. abdulwahab, s.m.thahab and asmaa h.dhiaa -available online at: www.iasj.net ijcpe vol.17 no.2 (june 2016) 3 fig. 2, edx image of tio2 nps the peak from the spectrum reveals the presence of ti and o at 4.5 and 0.6 kev respectively. wavelength( nm) 300 400 500 600 a b s o r b a n c e ( a .u ) 1.4 1.6 1.8 2.0 2.2 2.4 2.6 fig. 3, uv-vis absorption spectrum of tio2/ddwnanofluids the present composition of ti and o reveals the formation of nonstoichometric tio2 which is superior for photocatalytic applications. the absorption spectrum of tio2 nanoparticles was measured by uv– visible absorption spectrometry. fig. (3) shows the variation of optical absorbance with wavelength. the absorption band edges were estimated around 340 nm (about 3.6 ev). fig. (4) shows the measured thermal conductivity of tio2/ddw nanofluid as a function of tio2 nanoparticles volume concentrations at different temperature values. it is observed that the thermal conductivity increases with increasing both tio2 volume concentrations and temperature range from 15 to 30 o c. in addition, the thermal conductivity of nanofluids is nearly constant at low particle concentrations (less than 1% by volume), for example the increase in the thermal conductivity of a 1.5% nanofluids at 20 o c is about 39 % whereas it is about 44 % at 30 o c in case of nanofluids, brownian motion of nanoparticles causes change of temperature and clustering of nanoparticles, which results in remarkable changes of thermal conductivity of nanofluids with temperature. temperature, °c 14 16 18 20 22 24 26 28 30 32 t h e r m a l c o n c u c t iv it y ( w / m . k ) 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 0 0.1% 0.5% 1% 1.5% fig. 4, thermal conductivity of tio2/ddw nanofluids versus temperatures at different tio2nanoparticle volume concentration experimental study of thermophysical properties of tio2 nanofluid 4 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net temperature,°c 14 16 18 20 22 24 26 28 30 32 t h e r m a l c o n d u c t iv it y ( w / m . k ) 0.14 0.16 0.18 0.20 0.22 0.24 0.26 0.28 0.30 0.32 0.34 0 0.1% 0.5% 1% 1.5% fig. 5, thermal conductivity of tio2/ethanol nanofluids versus temperatures at different tio2 nanoparticle volume concentration since water has a higher thermal conductivity than ethanol, any presence of water in ethanol would lead to an increase in the effective thermal conductivity. therefore, presence of water in ethanol based nanofluids could lead to an erroneous conclusion about the enhancement, which is due to the presence of nanoparticles by sunder [6]. differences in the improvement of performance can be attributable to variations of the resistance of thermal boundary about the nanoparticles happening for diverse base fluids [7]. fig. (6) shows the experimental thermal conductivity results of tio2 nanofluids obtained in the experiment in comparison with the three conductivity models by maxwell, hamilton and brugeman show in table (2) below: table 2, effective thermal conductivity correlations for nanofluids reference correlation maxwell’s spherical, low volume fractions, random distributed particles hamilton and crosser ( ) ( )( ) ( ) ( ) spherical, low volume fractions, random distributed particles, for non-spherical n=6 bruggeman ( ) ( )( ) binary mixture, homogeneous, no limitations on the concentration, random distributed particles the thermal conductivity of tio2 nanofluids conducted by these three models is far less than the experimental thermal conductivity because the diverse of assumptions used in the experimental such as (spherical particle, no change in particle size and ≥ 1.5% volume concentration) compared with other models in table (2). the probable parameters which promote thermal conductivity enhancement are stochastic and brownian motion of nanoparticles in the base fluid. the temperature is another factor which is responsible for particle random movements which in turn results in enhanced thermal conductivity. majid i. abdulwahab, s.m.thahab and asmaa h.dhiaa -available online at: www.iasj.net ijcpe vol.17 no.2 (june 2016) 5 tio 2 nanoparticle volume persent 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 t h e r m a l c o n d u c ti v it y ( w /m k ) 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 hamilton bruggeman implicit maxwell expermintal fig. 6, comparison between theoretical and experimental behaviour of thermal conductivity of tio2 nps temperature, °c 14 16 18 20 22 24 26 28 30 32 v is c o s ty ( k g /m .s ) 0.000 0.001 0.002 0.003 0.004 0.005 0.006 0 0.1% 0.5% 1% 1.5% fig. 7, the viscosity of tio2/ddw nanofluids as a function of tio2 nps volume concentration measured at different temperatures fig. (7) and (8) show the variation of viscosity value as a function of tio2 volume concentration. it is observed that viscosity increases slightly with the increases of tio2 volume concentration of nanoparticles in nanofluids (ddw and ethanol). however, the viscosity of nanofluids is significantly higher when compared to base fluid due to presence of nanosized particles. at higher temperatures, the forces between the tio2 nanoparticles and the base fluid are weakened, causing a decrease in value of viscosity. for example at 1.5% viscosity is 5.49 at 15 o c and decrease to3.97 at 30 o c. temperature, °c 14 16 18 20 22 24 26 28 30 32 v is c o s it y ( k g /m .s ) 0.000 0.001 0.002 0.003 0.004 0.005 0.006 0 0.1% 0.5% 1% 1.5% fig. 8, the viscosity of tio2/ethanol nanofluids as a function of tio2 nps volume concentration measured at different temperatures. fig. (9) show the variation of ph value of nano-fluids as a function of tio2 volume concentration. it was observed that at 1.5% volume concentration of tio2 nanoparticles, the ph value decreased to 7.13 in the case of tio2/ddw and to 8.2 in the case of tio2/ethanol nanofluids. it can be observed that for tio2/ddwnanofluid, the ph value decreased from 7.7 at 1% to 7.13 at 1.5% volume concentration of tio2 nanoparticles. in the same trend, the ph value decreased from 8.56 to 8.2 accordingly in the case of tio2/ethanol nanofluid. this is ascribed to the effects of nanoparticles, which are identified to appearance clusters; this clustering can effect in quick transfer of heat over comparatively great ranges ago heat can be conducted extremely faster before particles of solid when compared to matrix of liquid, by ravi babu [8]. experimental study of thermophysical properties of tio2 nanofluid 6 ijcpe vol.17 no.2 (june 2016) -available online at: www.iasj.net nanopartical volume percent 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 p h 6.8 7.0 7.2 7.4 7.6 7.8 8.0 8.2 8.4 8.6 8.8 water ethanol fig. 9, ph of tio2 nanofluids in different base fluids as a function of volume fraction concentration conclusions in this paper the effective thermal conductivities, viscosities and ph of water and ethanol based nanofluids containing tio2 nanoparticles are investigated experimental. the presence of tio2 nanoparticle in base fluid is capable of enhancement the thermal conductivity of base fluid. the level of the base fluid enhancement depends on the amount of nanoparticle added to base fluid at the concentration of 1.5 vol. %; the thermal conductivity enhancement of 51.1% at 30 o c compared to base fluid was recorded. also thermal conductivity of nanofluids increases with the increase in temperature. the viscosity of nanofluids was significantly higher as compared to the base fluid for two the nanofluids tested. the viscosity of tio2/ddwwas found to be 5.49*10 -3 kg.m/s at 15 o c and it decreased to 3.97*10 -3 kg.m/s at 30 o c at a 1.5% tio2 nanoparticles. reference 1choi, s. u. s. ()., singer, a. and wang., h. p., 1995, “enhancing thermal conductivity of fluids with nanoparticles, in developments and applications of non-newtonian flows”, american society of mechanical engineers, vol. 66, p. 99–105. 2castillo, n., olguin, d., conde g.a., jiménez, s.s., 2004, “structural and morphological properties of tio2 thin films prepared by spray pyrolysis”, revista mexicana de física50 (4) 382. 3yoo, d.h., hongb, k.s., yang., h.s., 2006, “study of thermal conductivity of nanofluids for the application of heat transfer fluids”. thermochimicaacta, 455, pp.66-69. 4kim, s.h., choi, s.r., kim,d., 2007, “thermal conductivity of metal-oxide nanofluids: partical size dependence and effect of laser irradiation”. transaction of asme, 129, pp.298-307. 5us research nanomaterials, inc. the advanced nanomaterials provider 3302 twig leaf lane, houston, tx 77084, usa phone: 832-460-3661, fax: 281-492-8628 e-mail: service@us-nano.com; tech@usnano.com website: www.us-nano.com 6syam, l.,s. , manoj, k .s., ramana, e.v. , singh ,b. , joségrácio & antonio sousa, c. m., 2014, “enhanced thermal conductivity and viscosity of nanodiamond-nickel nanocompositenanofluids”, scientific reports 4, no.:4039. 7asmaa h. d., 2015, “investigation of thermal transport properties enhancement of nanoparticles suspensions in the application of nanofluids”, ph.d thesis, baghdad university. 8ravi babu, s., ramesh, p. b., dr. rambabu, v., 2013, “effects of some parameters on thermal conductivity of nanofluids and mechanisms of heat transfer improvement”, international journal of engineering research and applications (ijera), issue 4, vol. 3, pp. 2136-2140. http://www.us-nano.com/ file:///c:/users/asmaa/desktop/new%20folder/enhanced%20thermal%20conductivity%20and%20viscosity%20of%20nanodiamond-nickel%20nanocomposite%20nanofluids%20%20%20scientific%20reports%20%20%20nature%20publishing%20group.htm%23auth-2 file:///c:/users/asmaa/desktop/new%20folder/enhanced%20thermal%20conductivity%20and%20viscosity%20of%20nanodiamond-nickel%20nanocomposite%20nanofluids%20%20%20scientific%20reports%20%20%20nature%20publishing%20group.htm%23auth-3 file:///c:/users/asmaa/desktop/new%20folder/enhanced%20thermal%20conductivity%20and%20viscosity%20of%20nanodiamond-nickel%20nanocomposite%20nanofluids%20%20%20scientific%20reports%20%20%20nature%20publishing%20group.htm%23auth-4 file:///c:/users/asmaa/desktop/new%20folder/enhanced%20thermal%20conductivity%20and%20viscosity%20of%20nanodiamond-nickel%20nanocomposite%20nanofluids%20%20%20scientific%20reports%20%20%20nature%20publishing%20group.htm%23auth-5 file:///c:/users/asmaa/desktop/new%20folder/enhanced%20thermal%20conductivity%20and%20viscosity%20of%20nanodiamond-nickel%20nanocomposite%20nanofluids%20%20%20scientific%20reports%20%20%20nature%20publishing%20group.htm%23auth-6 available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.21 no.1 (march 2020) 23 – 31 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: hussam jumaah mousa, email: jmhussam@gmail.com, name: hussein qasim hussein, email: husseinqassab@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. adsorptive desulfurization of iraqi heavy naphtha using different metals over nano y zeolite on carbon nanotube hussam jumaah mousa and hussein qasim hussein chemical engineering department, college of engineering, university of baghdad abstract the present research was conducted to reduce the sulfur content of iraqi heavy naphtha by adsorption using different metals oxides over y-zeolite. the y-zeolite was synthesized by a sol-gel technique. the average size of zeolite was 92.39 nm, surface area 558 m 2 /g, and pore volume 0.231 cm 3 /g. the metals of nickel, zinc, and copper were dispersed by an impregnation method to prepare ni/hy, zn/hy, cu/hy, and ni + zn /hy catalysts for desulfurization. the adsorptive desulfurization was carried out in a batch mode at different operating conditions such as mixing time (10,15,30,60, and 600 min) and catalyst dosage (0.2,0.4,0.6,0.8,1, and 1.2 g). the most of the sulfur compounds were removed at 10 min for all catalyst types. the maximum sulfur removal was 56% using (ni+zn)/hy catalyst at 1.2 g dose for 24 h. the adsorption kinetics and isotherm of sulfur removal were studied, and results indicated that desulfurization adsorption kinetic was 2 nd order, and temkin and freundlich models were the best representation isotherm. keywords: carbon nanotube, nano y zeolite, naphtha, adsorption desulfurization received on 09/03/2019, accepted on 03/04/2019, published on 30/03/0220 https://doi.org/10.31699/ijcpe.2020.1.4 1introduction naphtha usually contain a small amount of sulfur compound. this sulfur causes many problems such as the catalyst poisoning and deactivation in processing, corrosion of equipment and the oxidation of sulfur compounds to sox during fuel combustion. sulfur exists in amounts from thousands parts per million to about close to hundred ‎[1]. environmental regulations have been introduced in many countries around the world to reduce the sulfur content of distillate fuels to ultra-low levels (10 ppm). the aim of this research is lowering the transportation fuel engine’s harmful exhaust emissions and improving air quality ‎[2]. a new selective adsorption process for removing sulfur, the main objective of the process is to selectively adsorb sulfur from fuels, and non-sulfur containing hydrocarbons such as aromatic, olefin hydrocarbons and cyclic paraffinic hydrocarbons remain unchanged. the adsorbent containing transition metal compound supported on silica gel has been used. the adsorption experiments were accomplished under ambient temperature from room temperature to 250 o c and atmospheric pressure in the adsorption column. a unique characteristic can be adsorbed without using hydrogen gas ‎[3]. adsorptive desulfurization processes are considered among the most economically attractive techniques due to their simple operating conditions, availability of inexpensive and the re-generable adsorbents such as reduced metals, metal oxides, alumina, metal sulfides, zeolites, silica, and activated carbon this process occurs as the sulfur molecules attach to the adsorbent and stay there separate from the fuel ‎[4].the main part of any adsorption process is a porous solid medium as it offers high surface area or high micropore volume that is translated into high adsorption capacity the difficulty in adsorbent development is that it must preferentially adsorb the sulfur-containing compounds over competing hydrocarbons, namely aromatics have a high adsorption capacity that it will have a high ratio of sulfur removed per gram of adsorbent be capable of regeneration such that the adsorbent can be reused. there are many types of adsorbents that have been heavily explored in literature, primarily: supported metals, metal oxides, activated carbons, ionic liquids, and metal loaded zeolites ‎[4]. a classical definition of zeolite is a crystalline aluminosilicate with a three-dimensional framework structure that forms uniformly sized pores of molecular dimensions. y-type zeolites are among the most widely used zeolites in catalysis, especially for the conversion of hydrocarbons, and this thanks to a structure with large pores allowing the adsorption of a large variety of molecules, but also a thermal stability a remarkable opportunity to perform multiple structural modifications according to the reaction conditions ‎[5]. nanocrystalline zeolite particles are becoming an important material in many technical applications. https://doi.org/10.31699/ijcpe.2020.1.4 h. j. mousa and h. q. hussein / iraqi journal of chemical and petroleum engineering 21,1 (2020) 23 31 46 synthetic methods that minimize the zeolite crystal diameter, while providing a narrow particle size distribution, are of primary importance in these technical applications ‎[6]. modern research lacks the techniques to synthesize designed properties of many nanomaterials also the need to interface these nanomaterials with microscale and macroscale platforms. the synthesis of zeolite or silicabased material has shown a particular interest in the carbon nanotube (cnt), due to its enhanced physical properties and particle size ‎[7]. the objective of this work is to reduce the sulfur content of iraqi heavy naphtha by adsorption. nano y zeolite was prepared with a multi-wall carbon nanotube (mwcnt) and transformed into hy type. various types of adsorbents were prepared by dispersion of different metals over the zeolite such as ni/hy, cu/hy and zn/hy for the batch adsorption desulfurization which carried out at different operating conditions. the adsorption isotherm and kinetics of desulfurization were studied. 2experimental work 2.1. materials heavy naphtha 600 ppm sulfur content was supplied from midland refineries company/al-dura refinery. sodium aluminate was provided by kunshan yalong trading co., ltd china. sodium aluminate has a molecular weight of 62, purity % =50-56(al2o3), 40-45 (na2o). sodium silicate (na2sio3) was provided by sigma aldrich chemical has a molecular weight of 122, purity % =10.63 na2o, 26.5 sio2. sodium hydroxide (naoh) was provided by sigma aldrich has a molecular weight of 40, purity % =99.5. ammonium chloride was provided by merck. the multiwall carbon nanotubes (mwcnt) used in the experiment was supplied by zhengzhou dongyao materials company with purity 97 % and the surface area 231.856 m 2 /g. 2.2. synthesis of nano y zeolite the sol-gel and hydrothermal method were applied for the synthesis of nay zeolite and according to the following steps. the aging solution was prepared from 4.07 g sodium hydroxide pellets dissolved in 19.95 g of deionized water. 2.09 g of the sodium aluminate solution is stirred in a 100 ml plastic bottle until dissolution, then 33g of sodium silicate was added and aging for 24 h. the stock solution was 131 g of deionized water was added to 0.14 sodium hydroxide with 13.1 g sodium aluminate and 1 g mwcnt, the mixture was stirred then 206 g of sodium silicate was added and the mixture was mixed with 1600 rpm mixer for 20 min. the solutions prepared in the previous steps were mixed in a polypropylene bottle and subjected to homogenization for 24h at room temperature; the product was centrifuged for 15 min for mwcnt separation and then the mwcnt was transferred to jacketed stainless steel autoclaves. for crystallization, the autoclave was made from stainless steel and lined with polytetrafluoroethylene (ptfe), the mixture was heated at 100 ° c for 24 hours without agitation. the product was then filtered, washed with distilled water until neutralization (ph = 7) and dried in an oven at 110 ° c for 24 h. then, it was calcined at 550 c for 3 h. 2.3. ion exchange of nay zeolite the prepared nay zeolite was transformed into hy type zeolite using the ion exchange method.10 g of y zeolite was mixed with 42.79 g of ammonium chloride and 200ml distilled water which reflexed at 70 c for 2 h. the solution was left at room temperature overnight to complete the ion exchange process then the solution was filtered, washed and dried at 110 c overnight. the produced zeolite was calcined in a furnace at 525 c for 3 hours. 2.4. preparation of metal oxide-based catalyst different types of metal oxide-based catalysts were prepared. an aqueous solution of different metal salt was prepared by dissolving 0.66g of zn (no3)2, 0.72g of ni (no3)2, 2h2o and 0.68 g of cu (no3)2. 2h2o in 10 ml distilled water. 5 g of hy zeolite was placed in the vacuum flask for 15 min to discharge air from zeolite pores, then an appropriate volume of metal solution was added. the impregnation was carried out at room temperature for 2h. the impregnated zeolite was dried at 110 o c overnight and calcination at 550 o c for 3h. 2.5. adsorption desulfurization process 100 ml of heavy naphtha was poured in a 150 ml flask with an initial sulfur concentration 600 ppm. the batch adsorption desulfurization experiments were conducted at different operating conditions such as catalyst dose range (0.2-1.2 g) and mixing time (10 min to 10 h) for various catalyst types. 3results and discussion 3.1. catalyst characterizations the identification of the phases formed by x-ray diffraction shows that the zeolite type y is pure and well crystallized with a better yield of crystals is obtained from a gel initial stoichiometric composition. the x-ray diffraction of the material is given in fig. 1. this spectrum shows the characteristic diffraction peaks of a na-y zeolite, as are presented in the collection of simulated powder diagrams for zeolites ‎[8]. all the peaks of diffraction were indexed in the cubic system. the mesh parameter determined from the structural refinement is a = 24.678 å. xrd analyses were carried out at room temperature using cukα radiation nickel filter (λ= 1.5418a) and energy condition of (4 kv and 3 ma). h. j. mousa and h. q. hussein / iraqi journal of chemical and petroleum engineering 21,1 (2020) 23 31 47 fig. 1. xrd pattern for zeolite y with the using of mwcnt the afm has been performed to the prepared zeolite with the use of mwcnt. the topography of the surface of the prepared zeolite was taken by the atomic force microscope. these images show details about particle size distribution. afm allowed a detailed observation of nanometer-size scale at crystal surfaces as shown in fig. 2 fig. 2. the afm analysis of nay zeolite with mwcnt the surface area and pore volume have been measured for prepared y-zeolite with mwcnt. the bet surface area of the zeolite was 558 m 2 /g and the pore volume was 0.231 cm 3 /g. located petroleum research and development center. 3.2. adsorption desulfurization of naphtha sulfur removal from iraqi heavy naphtha by adsorption desulfurization was carried out by using different types of metals oxides base zeolite catalysts. all experiments were conducted on a batch mode with various operating conditions like catalyst type, catalyst dose and mixing time. a. effect of time on sulfur removal the removal of sulfur from iraqi heavy naphtha has been studied with the adsorption time using a different type of adsorbent. fig. 3 shows the effect of adsorption time on the percentage of sulfur removal. fig. 3. sulfur removal versus time for different metal oxide-based catalyst it is clear that after 10 min a major sulfur removal was achieved for all adsorbent types. the sulfur removal as a function of time shows that the adsorption equilibrium was reached approximately 1 h. at 10 min the percentage of sulfur removal was 51.7% for ni/hy catalyst, while the removal was 45.6% for zn/hy, 45.2% for zn+ni /hy, and 37% for cu/hy. the sulfur removal increased gradually with time, until 1h. the lowest sulfur removal % was achieved with nay and hy pure zeolite. in the case of hy, maximum removal was (28.4 %) at 10 min, and no change was detected after 10 h. meanwhile, nay showed the least sulfur removal among other types. at 10 min percentage was (22%) and slightly increased to (25%) at 1 h and (30 %) at 10 h. the best removal of sulfur achieved for the ni/hy loading and ni+zn /hy, the sulfur removal in both of them after 1h was 55% and 55.3% respectively. as for the zn/hy, after 10 hours the sulfur removal was 48.7%. after 10 h, all the catalyst types reach the maximum of their removal. the max removal of ni+zn /hy was 56.2% followed by ni/hy were the removal was 55.1%. b. effect of adsorbent mass on sulfur removal in order to optimize the mass of each catalyst type for the removal of sulfur from naphtha, a study was conducted with different adsorbent concentrations varied from 0.2 mg up to 1.2 mg in 100 ml solution. fig. 4. sulfur removal versus adsorbent dose for different metal oxide-based catalyst h. j. mousa and h. q. hussein / iraqi journal of chemical and petroleum engineering 21,1 (2020) 23 31 48 fig. 4, shows the effect of catalyst dose on removal percentage. at 0.2 gm the percentage removal was 45.68 % for ni/hy and ni+zn/hy, 34.48 % for zn/hy, 34.5% for ni/nay, 31% for cu/hy, 27.86 for hy and 22.4 for nay. the sulfur removal increases with catalyst dose increase until it reaches 56% at 1.2 gm for ni/hy and ni+zn/hy. for cu/hy and zn/nay also the removal values were close at any dose, it starts with 31% removal at 0.2 g, 32.75 at 0.4 g, 33.96 for 0.6g and for 0.8, 1 and 1.2 the removal was 34%. for pure hy and nay alone without metal ions, the removal was the lowest due to the absences of the metal ion that can react with the sulfur ions in the sulfur compound ‎[9]-‎[12]. the removal of both was constant 22.4% for nay and 27.9% for hy. for zn+ni /hy, the removal with dose 0.2g was 45.68% and at 0.4 the removal increase to 50% while at 0.6g the removal was 53.44%. at the rest of the doses, the removal didn’t change much. the removal increase as the catalyst does increase at any catalyst type except for the nay zeolite were the removal has no significant effect on nay dose. the nay zeolite base has lower performance than the hy base this is due to the presence of sodium ion in the catalyst the decrease its overall activity ‎[8],‎[13]. at any catalyst dosing, the highest removal was achieved for ni/hy and ni+zn /hy catalyst followed by zn/hy then ni/nay while the lowest removal was for nay zeolite. c. effect of nickel concentration on sulfur removal the effect of ni loading concentration on the percent of sulfur removal from iraqi heavy naphtha has been studied as shown in fig. 5. it’s clear that the sulfur removal was increased with ni concentration increase. the sulfur removal was 52% and 54% at 2% and at 3% respectively, while sulfur removal rise to 56% at 6%. fig. 5. effect of nio concentration over hy zeolite on sulfur removal results show that the ni concentration increase has a slight effect on the percentage of sulfur removal. the ni concentration increase from 2% to 6% led to increased sulfur removal 4% only. this result confers a favor to use low metal concentration on a carrier and it acceptable from an economic point of view. 3.3. kinetic study of sulfur adsorption the kinetics of sulfur adsorption on ni-based zeolite was analyzed to see the best-fitted adsorption order, the comparison between the experimental data and the predicted model are based on the values of the correlation coefficients (r 2 ) hence the r 2 value closer to the unit will indicate the correct model to correctly describe the kinetics. for each temperature, the curve of ln (qe -qt) as a function of time t (figure 6) is a straight line indicating that the adsorption kinetics is of the first order, from which the constant k1, is estimated. fig. 6. time vs ln (qe-qt) pseudo first order kinetic in such circumstances, figure 7 gives a linear relation, which allows the computation of qe from the slope and k2 to the ordinate. fig. 7. pseudo second-order relation so the advantage of using this model lies in the fact that there is no need to know the capacity of equilibrium from the experiments since it can be determined from the model by trying both first and second-order, it's noticeable that the second-order is more accurate ( r 2 =1) than the first order r 2 =0.9332. h. j. mousa and h. q. hussein / iraqi journal of chemical and petroleum engineering 21,1 (2020) 23 31 49 3.4. study of adsorption isotherms the study of isotherms was carried out to try to understand the adsorption phenomenon. these isotherms have been established at a different catalyst. the batch process was carried in 100 ml of naphtha solution and the initial concentration of sulfur was 600 ppm. the mixture is kept shaken so that the sulfur spread evenly throughout the solution. the concentration of sulfur in solution is monitored as a function of time, for temperatures ° c. a. freundlich model freundlich model, which gives an indication of the heterogeneity at the surface of the adsorbent, was applied to measure the adsorption capacity according to the following relation: (1) where: kf = freundlich isotherm constant (mg/g) n = adsorption intensity; ce = the equilibrium concentration of adsorbate (mg/l) qe = the amount of metal adsorbed per gram of the adsorbent at equilibrium (mg/g). the linear form of the freundlich equation can be written in the form logarithmic according to the following relation: (2) the experimental results obtained for isotherms given in fig. 8. fig. 8. freundlich isotherm of adsorption process for all catalysts types h. j. mousa and h. q. hussein / iraqi journal of chemical and petroleum engineering 21,1 (2020) 23 31 4: according to figure 8, the three curves illustrating the isotherms show adsorption follows the freundlich model, the experimental results can be correlated by the freundlich equation and the correlation coefficients are close to unity. the freundlich constants k and n were determined from the isotherms and their values are summarized in appendix a. from table (1) the n value for ni/hy, ni/nay, ni+zn/hy, zn/hy lies between 1 and 10 means this model is favorable for these types of catalyst. while for cu/hy, hy and nay n value is greater than 10 means it’s not favorable. b. langmuir isotherm the langmuir model allows determining if a monolayer is adsorbed and if there is no interaction between the adsorbed molecules. the langmuir equation is valid for only one monolayer adsorbed with a well-defined number of adsorption sites uniform and identical energetically according to the following relation: (3) where: ce = the equilibrium concentration of adsorbate (mg/l -1 ), qe = the amount of metal adsorbed per gram of the adsorbent at equilibrium (mg/g). qo = maximum monolayer coverage capacity (mg/g) kl = langmuir isotherm constant (l/mg). the langmuir equation can be written also in this form: (4) by representing the experimental results, for the three temperatures studied, according to the langmuir equation gives the isotherms of fig. 9. fig. 9. langmuir isotherm of adsorption process for all catalysts types h. j. mousa and h. q. hussein / iraqi journal of chemical and petroleum engineering 21,1 (2020) 23 31 4; kl: constant related to adsorption energy (langmuir model). a value of rl less than unity represents favorable adsorption and a value greater than unity represents unfavorable adsorption. the rl shown in table 1 was greater than 1 for all types for all catalysts which means that the model is also unfavorable. c. isotherm of temkin the temkin isotherm assumes that the decrease in adsorption heat is linear and that adsorption is characterized by a uniform distribution of binding energies. the temkin isotherm was used in the following form [9,10] qe = ln(at ce) (5) qe = ln at + ln ce (6) b= (7) qe= b ln at + b ln ce (8) at =temkin isotherm equilibrium binding constant (l/g), b = temkin isotherm constant, r= universal gas constant (8.314 j/mol/k), t= temperature, b = constant related to heat of sorption (j/mol). fig. 10. temkin isotherm of adsorption process for all catalysts types h. j. mousa and h. q. hussein / iraqi journal of chemical and petroleum engineering 21,1 (2020) 23 31 53 the curve of qe versus ln ce (figure 10) allows the determination of the isothermal constants of b and a from the slope and interception, respectively. the experimental results can be correlated by the temkin equation and the correlation coefficients are close to unity. the temkin constants at and b were determined from the isotherms and their values are summarized in appendix a. all the isotherm result has been summarized in table 1. table 1. the isotherm parameters isotherm parameters ni/hy ni/nay zn/hy ni +zn/hy hy nay cu/hy langmuir qm -8.733 -6.89 -12.34 -9.823 -0.123 -0.122 -1.486 kl -3.04e-3 -2.5e-3 -2.44e-3 -3.01e-3 -2.43e-3 -2.22e-3 -2.47e-3 r 2 0.8404 0.8595 0.6399 0.8939 0.9608 0.9382 0.8461 rl 4.22 1.81 1.70 3.91 1.69 1.40 1.76 freundlich kf 2.9e-17 3.9e-18 2.8e-11 1.9e-15 0 0 5.30e-29 n 7.47 7.5303 4.89 6.7373 263.155 264.76 25.776 r 2 0.955 0.9505 0.7836 0.977 0.8917 0.9864 0.9641 temkin b 649.74 295.75 281.42 591.75 9681.2 9794.8 1145.3 at 4.03e-3 3.59e-3 3.812e-3 4.13e-3 2.88e-3 2.24e-3 2.69e-3 r 2 0.9897 0.9026 0.9141 0.9723 0.9894 0.9996 0.9655 4conclusions the phase pattern by xrd indicated to y-zeolite catalyst, in spite of using mwcnt for the crystallization step, which referred to the success of using mwcnt for crystal growth. the y-zeolite was prepared with a narrow range particle size (55.17) nm by using mwcnt as a medium for crystal growth compared with the conventional method. most of the sulfur removal was achieved after 10min for all types of catalysts 51.7% for ni/hy. the sulfur removal increased with time, after 10h become slightly increased. ni concentration increase doesn ' t highly effect on a percent of sulfur removal, increasing concentration from 2% to 6% increase sulfur removal just 2% low metal concentration is acceptable from an economic point of view. experimental results have been applied by the models of freundlich, langmuir, temkin. it has also is that the freundlich and temkin model better describes the adsorption of sulfur than the langmuir model. the study of the kinetics of adsorption of sulfur made it possible to specify the order of the reaction. indeed, the two applied kinetic models, a model of 1st, and 2nd order model. by comparing the coefficients of regression of the curves corresponding to the two kinetic models, the 2nd order is closest to the unit. so we can say that the kinetics of the reaction sulfur adsorption is most likely of second order. nomenclature afm : atomic force microscopy bet : brunauar , emmett, teller sem : scanning electron microscopy mwcnt : multi wall carbon nano tube xrd : x-ray diffraction references [1] zeng y., ju shengui,* xing weihong and chen changlin, (2008)." adsorption of mercaptan from model gasoline on 13x loaded with zn2+", the canadian journal of chemical engineering, 86,186187, [2] n. bettahar ,f.belkhadem ,f. hamidi, (2011) .”effect of synthesis parameters on properties zeolites of type y and lta” [3] m. a. severance, "nanocrystalline zeolites: synthesis, mechanism, and applications." phd diss., the ohio state university, 2014. [4] lee n s, chung d s, han i t, kang j h, choi y s, kim h y, park s h, jin y w, yi w k, yun m j, jung j e, lee c j, jo s h, lee c g and kim j m (2001) application of carbon nanotubes to field emission displays diam. relat. mater. 265–70 [5] c. baerlocher, meier, l.b. mccusker, d.h. olson, (2007). “atlas of zeolite framework types”,6th edition, elsevier, amsterdam. [6] treacy m.m.j. and higgins j.b., 2001, “collection of simulated xrd powder patterns for zeolites”, 4th edition amsterdam: elsevier, 2001. [7] zhang, w., bao, x., guo, x., and wang, x. (1999). a high-resolution solid-state nmr study on nanostructured hzsm-5 zeolite. catal. lett. 60:89–94. [8] n. s. ahmedzeki and b. a. al-tabbakh, “catalytic reforming of iraqi naphtha over pt-ti / hy zeolite catalyst”, ijcpe, vol. 17, no. 3, pp. 45-56, sep. 2016. [9] iver schmidt, i., boisen, a., gustavsson, e., ståhl, k., pehrson, s., dahl, s., carlsson, a. and jacobsen, c.j., 2001. carbon nanotube templated growth of mesoporous zeolite single crystals. chemistry of materials, 13(12), pp.4416-4418. [10] barbara pawelec , rufino m. navarro, jose miguel campos-martin and jose l. g. fierro* " towards near zero-sulfur liquid fuels: a perspective review" catal.sci. technol. , 1, 23–42,(2011). https://onlinelibrary.wiley.com/doi/abs/10.1002/cjce.20019 https://onlinelibrary.wiley.com/doi/abs/10.1002/cjce.20019 https://onlinelibrary.wiley.com/doi/abs/10.1002/cjce.20019 https://onlinelibrary.wiley.com/doi/abs/10.1002/cjce.20019 https://onlinelibrary.wiley.com/doi/abs/10.1002/cjce.20019 https://etd.ohiolink.edu/pg_10?0::no:10:p10_accession_num:osu1387817713 https://etd.ohiolink.edu/pg_10?0::no:10:p10_accession_num:osu1387817713 https://etd.ohiolink.edu/pg_10?0::no:10:p10_accession_num:osu1387817713 https://www.sciencedirect.com/science/article/abs/pii/s0925963500004787 https://www.sciencedirect.com/science/article/abs/pii/s0925963500004787 https://www.sciencedirect.com/science/article/abs/pii/s0925963500004787 https://www.sciencedirect.com/science/article/abs/pii/s0925963500004787 https://www.sciencedirect.com/science/article/abs/pii/s0925963500004787 https://books.google.iq/books?hl=en&lr=&id=66z0m59omwcc&oi=fnd&pg=pp1&dq=%5b5%5d%09c.+baerlocher,+meier,+l.b.+mccusker,+d.h.+olson,+(2007).+%e2%80%9catlas+of+zeolite+framework+types%e2%80%9d,6th+edition,+elsevier,+amsterdam.&ots=rpotg5fhsd&sig=srfaavemyya7tchznzyju5gm_mi&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=66z0m59omwcc&oi=fnd&pg=pp1&dq=%5b5%5d%09c.+baerlocher,+meier,+l.b.+mccusker,+d.h.+olson,+(2007).+%e2%80%9catlas+of+zeolite+framework+types%e2%80%9d,6th+edition,+elsevier,+amsterdam.&ots=rpotg5fhsd&sig=srfaavemyya7tchznzyju5gm_mi&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=66z0m59omwcc&oi=fnd&pg=pp1&dq=%5b5%5d%09c.+baerlocher,+meier,+l.b.+mccusker,+d.h.+olson,+(2007).+%e2%80%9catlas+of+zeolite+framework+types%e2%80%9d,6th+edition,+elsevier,+amsterdam.&ots=rpotg5fhsd&sig=srfaavemyya7tchznzyju5gm_mi&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=9mi94f2mh0wc&oi=fnd&pg=pp1&dq=%5b6%5d%09treacy+m.m.j.+and+higgins+j.b.,+2001,+%e2%80%9ccollection+of+simulated+xrd+powder+patterns+for+zeolites%e2%80%9d,+4th+edition+amsterdam:+elsevier,+2001.&ots=yioza-pilf&sig=gg5tqib01w0n6tsbjypldzsc5zi&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=9mi94f2mh0wc&oi=fnd&pg=pp1&dq=%5b6%5d%09treacy+m.m.j.+and+higgins+j.b.,+2001,+%e2%80%9ccollection+of+simulated+xrd+powder+patterns+for+zeolites%e2%80%9d,+4th+edition+amsterdam:+elsevier,+2001.&ots=yioza-pilf&sig=gg5tqib01w0n6tsbjypldzsc5zi&redir_esc=y#v=onepage&q&f=false https://books.google.iq/books?hl=en&lr=&id=9mi94f2mh0wc&oi=fnd&pg=pp1&dq=%5b6%5d%09treacy+m.m.j.+and+higgins+j.b.,+2001,+%e2%80%9ccollection+of+simulated+xrd+powder+patterns+for+zeolites%e2%80%9d,+4th+edition+amsterdam:+elsevier,+2001.&ots=yioza-pilf&sig=gg5tqib01w0n6tsbjypldzsc5zi&redir_esc=y#v=onepage&q&f=false https://link.springer.com/article/10.1023/a:1019061714047 https://link.springer.com/article/10.1023/a:1019061714047 https://link.springer.com/article/10.1023/a:1019061714047 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/212 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/212 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/212 https://pubs.acs.org/doi/abs/10.1021/cm011206h https://pubs.acs.org/doi/abs/10.1021/cm011206h https://pubs.acs.org/doi/abs/10.1021/cm011206h https://pubs.acs.org/doi/abs/10.1021/cm011206h https://pubs.acs.org/doi/abs/10.1021/cm011206h https://pubs.rsc.org/en/content/articlehtml/2011/cy/c0cy00049c https://pubs.rsc.org/en/content/articlehtml/2011/cy/c0cy00049c https://pubs.rsc.org/en/content/articlehtml/2011/cy/c0cy00049c https://pubs.rsc.org/en/content/articlehtml/2011/cy/c0cy00049c h. j. mousa and h. q. hussein / iraqi journal of chemical and petroleum engineering 21,1 (2020) 23 31 53 [11] a.-h. a. mohammed and m. a. abdulwahhab, “naphtha desulfurization by prepare cu-ni-zeolite adsorbent”, ijcpe, vol. 15, no. 4, pp. 9-14, dec. 2014. [12] ibrahim, n.k., 2015. desulfurization and kinetic study of diesel fuel by batch adsorption on activated carbon. engineering and technology journal, 33(8 part (a) engineering), pp.1901-1916. [13] hassan, s.s., kareem, s.h. and ugal, j.r., 2013. adsorption of hydrogen sulphide on the zeolite type a synthezied from iraqi kaoline. baghdad science journal, 10(3), pp.1023-1033. yامتزاز الكبريت من النافثا الثقيمة العراقية باستخدام معادن مختمفة فوق زيوليت نانو حسين قاسم حسينو حسام موسى جمعه قسم الهندسة الكيمياوية ، كمية الهندسة ، جامعة بغداد الخالصة في البحث الحالي الذي اجريته لدراسه تاثير االمتزاز االنتقائي الزالة مركبات الكبريت في النافثا العراقيه وتحميمه sol-gelبتقنية y-zeoliteالثقيمه الذي يتم انتاجها من مصفى الدورة . وتمت عمميه االزالة باستخدام بأكسيد فمزي مختمف. تم الكشف عن نمط الطور والبنية الكيميائية وحجم الجسيمات ومساحة السطح بواسطة xrd وafm وحجم نانومتر( 92.39) وكان الزيواليت حجمعمى التوالي. أظهرت النتائج أن متوسط .نانومتر( 92.39) الجسيمات تم غ/ 3 كم( 0.231) قميلا كبير مسامي حجم مع جم/ 2 م (555) لتكون السطحية المساحة تحسين تم و zn / hyو ni /hyمى أنواع مختمفة وتركيزات من المحفزات القائمة عمى أكاسيد الفمزات مثل ع الحصول cu / hy بواسطة طريقة التشريب المتصاص الكبريت من النافثا الثقيمة العراقية. تم ازالة الكبريت بعممية دفعية دقيقة( وكمية العامل المساعد 600و 10،15،30،60في ظروف تشغيل مختمفة مثل وقت الخمط ) اع العامل المساعد. دقائق( لجميع أنو 10(. تم إزالة مركبات الكبريت بعد )g 1.2و 0.2،0.4،0.6،0.5،1) خلل 1.2gفي جرعة hy / (ni + zn)٪ باستخدام العامل المساعد 56كان الحد األقصى إلزالة الكبريت 24hr ، جعمت دراسة الحركية االمتزازية إلزالة الكبريت من الممكن تحديد الترتيب الحركي. في الواقع . ى الوحدة. لذلك يمكننا القول أن حركية تفاعل امتصاص معاملت االنحدار من الدرجة الثانية هي األقرب إل كانت أفضل freundlichو temkinالكبريت هي في الغالب من الدرجة الثانية. تظهر الدراسة أن النماذج .isothermلتمثيل النتيجة التجريبية الكبريت باالمتزازإزالة ،النافثا ، نانو y : األنبوب النانوي الكربوني، زيوليتالدالة الكممات http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/292 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/292 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/292 https://www.iasj.net/iasj?func=article&aid=108831 https://www.iasj.net/iasj?func=article&aid=108831 https://www.iasj.net/iasj?func=article&aid=108831 https://www.iasj.net/iasj?func=article&aid=108831 https://www.iasj.net/iasj?func=article&aid=78133 https://www.iasj.net/iasj?func=article&aid=78133 https://www.iasj.net/iasj?func=article&aid=78133 https://www.iasj.net/iasj?func=article&aid=78133 available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.21 no.3 (september 2020) 57 – 66 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: yahya jirjees tawfeeq, email: yahyapetroleum@uokirkuk.edu.iq, name: jalal a. al-sudani, email: jalsud@uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. digital rock samples porosity analysis by otsu thresholding technique using matlab yahya j. tawfeeq and jalal a. al-sudani petroleum engineering department, college of engineering, university of baghdad, baghdad, iraq abstract porosity plays an essential role in petroleum engineering. it controls fluid storage in aquifers, connectivity of the pore structure control fluid flow through reservoir formations. to quantify the relationships between porosity, storage, transport and rock properties, however, the pore structure must be measured and quantitatively described. porosity estimation of digital image utilizing image processing essential for the reservoir rock analysis since the sample 2d porosity briefly described. the regular procedure utilizes the binarization process, which uses the pixel value threshold to convert the color and grayscale images to binary images. the idea is to accommodate the blue regions entirely with pores and transform it to white in resulting binary image. this paper presents the possibilities of using image processing for determining digital 2d rock samples porosity in carbonate reservoir rocks. matlab code created which automatically segment and determine the digital rock porosity, based on the otsu's thresholding algorithm. in this work, twenty-two samples of 2d thin section petrographic image reservoir rocks of one iraqi oil field are studied. the examples of thin section images are processed and digitized, utilizing matlab programming. in the present study, we have focused on determining of micro and macroporosity of the digital image. also, some pore void characteristics, such as area and perimeter, were calculated. digital 2d image analysis results are compared to laboratory core investigation results to determine the strength and restrictions of the digital image interpretation techniques. thin microscopic image porosity determined using otsu technique showed a moderate match with core porosity. keywords: digital rock physics, otsu thresholding, thin section image, porosity, macro pores, micro pores received on 26/06/2020, accepted on 22/08/2020, published on 30/09/2020 https://doi.org/10.31699/ijcpe.2020.3.8 1introduction image analysis has been used for many years to extract relevant information from digital microscopic images. image analysis includes all operations required to obtain quantified image information. the typical image analysis sequence involves image acquisition, processing, segmentation, measurements, data processing and interpretation. segmentation of images considers one of the essential techniques utilized to divide the image into its integrated portions for extracting the relevant image information [1]. briefly, the segmentation of the image transforms the representation of an image into its simplified shape that can be examined more critically and naturally [2], [3]. several practical image segmentation applications are available such as trace tumors and additional pathologies [4], [5], machine vision, object detection [6], face detection, medical imaging [7], [8], anatomic building studies and diagnoses [9], fingerprint recognition and video surveillance. several techniques of image segmentation, such as thresholding [10], edge-based segmentation [11], and compression-based methods [12], have been taken during recent decades. in image processing techniques, many algorithms used, such as artificial neural network [13], convolutional neural network [14], and k nearest neighbors. in all image segmentation methods, the simplest and most relevant and useful technique of dividing an image into the front class and the background class is thresholding technique [15]. the thresholding process converts the grayscale image into the binary image depending on the threshold values. the important of the thresholding process is to select an optimal threshold value when there are more threshold levels are implemented. several methods of thresholding are currently employed, including otsu technique, clustering [16] and utmost entropy technique [17]. otsu method is fast and ease of coding thresholding method among all the purposes mentioned above. because the otsu threshold operates on histograms (which are integer or float arrays of length 256) it's quite fast and approximately 90 lines matlab code needed. however, otsu technique is a histogram-based [18] threshold approach for automatic thresholding of the image. otsu's algorithm suggests that the image can be divided into two main categories: foreground and background. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:yahyapetroleum@uokirkuk.edu.iq mailto:jalsud@uobaghdad.edu.iq mailto:jalsud@uobaghdad.edu.iq http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2020.3.8 y. j. tawfeeq and j.a. al-sudani / iraqi journal of chemical and petroleum engineering 21,3 (2020) 57 66 58 the algorithm designed to find the best threshold value that divides the histogram into two classes that maximizes the variance between two classes. the development of the current otsu threshold to the multi-level threshold referred to as the multi-otsu thresholds [19]. porosity is the porous space fraction that the rock matrix does not occupy [20]. a comprehensive study of the distribution of porosity is essential for the reservoir evaluation project [21]. porosity is a crucial property of rock due to measuring potential storage volume of hydrocarbons. in the carbonate reservoir, porosity ranges about 0.01-0.35 [22]. the volume fraction of void spaces, i.e. non-rock space, divided by the total volume of the sample defined as porosity [23]. high porosity values indicate high capacities of the reservoir rocks to contain these fluids, while low porosity values indicate the opposite [24]. the porosity evaluated either through formation evaluation logs or through laboratory measurements on core samples. a general industry practice is to regard core measurements as ground truth. however, there can be uncertainties associated with core measurements especially when laboratory conditions ignored under which core measurements were made. there are certain factors that control porosity of a formation, pore and grain size distribution, mineralogy, sorting and diagenesis, etc. [25], [26]. characterizing these controlling factors require advanced logging and special analysis on core data (scal), yet some of these properties require alternate interpretation techniques. ‘digital image analysis of thin sections’ is presented as this alternate technique. porosity, mineralogy, pore size distribution and sorting analyzed through digital image analysis of thin sections. in this study, otsu's thresholding implemented for microscopic image segmentation. the samples of microscopic images are processed utilizing matlab programming. in the present study, microporosity and macroporosity of the digital image are determined. also, some pore void characteristics, such as area and perimeter, were calculated. 2material and methods in this work, twenty-two samples of 2d thin section petrographic image used for analyses from the core plugs taken from the buzurgan oil field. each sample was impregnated with blue-dyed epoxy, thin sectioned and then was stained for discrimination of carbonate minerals, the scanned image has resolution of about 10 𝜇m/pixel. the procedure of scanning and digitizing the image called ‘optical microscopy’ and is of lower resolution as compared to digital images obtained from ‘scanning electron microscopy’. the advantage of the former is that it is a fast technique to obtain digital images and a disadvantage that pore sizes less than 10 𝜇m cannot be quantitatively resolved with optical microscopy. in image processing, otsu's technique used to implement automatic image thresholding, and this method named after japanese scientist nobuyuki otsu [10]. the algorithm in the simplest form returns a single threshold of intensity to separate the pixels into two groups or classes, foreground and background. the algorithm searches deeply for the threshold that maximizes the variance of between-class or minimizes the variance of within-class. the fundamental concept is that suitable threshold classes must separate the intensity values in terms of their pixel and, conversely, that the optimum threshold would be a threshold providing the best class separation in terms of intensity values [27]. otsu's technique has the significant property, in relation to its optimality, that it is entirely based on computations executed on an image's histogram, an easily accessible 1-d array. let {0, 1, 2 … … … . . , 𝐿 − 1} are the separate intensity levels in a digital image of size (m.n) (row and column dimensions of the image) pixels, and assume (ni) is the number of pixels with intensity (i). the total image pixel is; 𝑀 𝑁 = 𝑛0 + 𝑛1 + 𝑛2+, , , , , , , , , +𝑛𝐿−1. the normalized histogram contains parts as [10]; 𝑝𝑖 = 𝑛𝑖 𝑀𝑁 (1) ∑ 𝑝𝑖 = 1 𝑎𝑛𝑑 𝑝𝑖 ≥ 0 𝐿−1 𝑖=0 (2) where: m.n = row and column dimensions of the image ni = the number of pixels with intensity (i) pi = probability distribution of intensity (i) i = intensity now, assume that a threshold (t) was selected with value (0 < t < l-1), and utilized this threshold to separate the digital input image into two classes or groups, (c1) and (c2). where (c1) involves all the image pixels that have intensity values ranges (0, t) and (c2) includes all the image pixels that have intensity values ranges (t+1, l-1). utilizing this threshold, probability 𝑃1(𝑇) of class c1 (i.e. background class) is given by the cumulative sum; 𝑃1(𝑇) = ∑ 𝑝𝑖 𝑇 𝑖=0 = ∑ 𝑛𝑖 𝑀𝑁 𝑇 𝑖=0 (3) where: t = threshold. in the same way, the probability of the second class 𝑃2(𝑇) (class c2, or foreground class) is given by; 𝑃2(𝑇) = ∑ 𝑝𝑖 𝐿−1 𝑖=𝑇+1 = 1 − 𝑃1(𝑇) (4) the class c1 mean intensity value of the pixels is given by; 𝜇1(𝑇) = ∑ 𝑖 𝑝( 𝑖 𝐶1 )𝑇𝑖=0 = ∑ 𝑖 𝑝( 𝐶1 𝑖 )𝑇𝑖=0 ( 𝑃(𝑖) 𝑃(𝐶1) ) = 1 𝑃1(𝑇) ∑ 𝑖 𝑝𝑖 𝑇 𝑖=0 (5) where: 𝜇1(𝑇) is mean intensity value for class c1. where 𝑃1(𝑇) is given in eq. (2). the term𝑝 ( 𝑖 𝐶1 )is the probability of value (i) which derives from class (c1). y. j. tawfeeq and j.a. al-sudani / iraqi journal of chemical and petroleum engineering 21,3 (2020) 57 66 59 the second part of the equation comes from bayes' formula. the third part comes from the fact 𝑝 ( 𝐶1 𝑖 ) = 1, probability of (c1) for given (i) equal to (1), since only class (c1) values is considered. while 𝑃(𝑖)is the probability of the (ith) value, which is simply the (ith) component of histogram(𝑝𝑖 ). finally, 𝑃(𝐶1) is the probability of class (c1) that is equal to eq. (3). in the same way, the class (c2) means intensity value of pixels given by; 𝜇2(𝑇) = ∑ 𝑖 𝑝( 𝑖 𝐶2 )𝐿−1𝑖=𝑇+1 = 1 𝑃2(𝑇) ∑ 𝑖 𝑝𝑖 𝐿−1 𝑖=𝑇+1 (6) where: 𝜇2(𝑇) is mean intensity value for class c2. the term𝑝 ( 𝑖 𝐶2 )is the probability of value (i) which derives from class (c2). the average intensity of the entire image (i.e., the global mean) given by; 𝜇𝐺 = ∑ 𝑖 𝑝(𝑖) 𝐿−1 𝑖=0 (7) where: 𝜇𝐺 = is a global mean or average intensity of the entire image by substitute of the previous results, the validity of the following two equations can be confirmed: 𝑃1𝜇1 + 𝑃2𝜇2 = 𝜇𝐺 (8) and 𝑃1 + 𝑃2 = 1 (9) where: 𝑃1 = background class (class c1) probability. 𝑃2= foreground class (class c2) probability. 𝜇1 = mean intensity value for class c1 𝜇2 = mean intensity value for class c2 𝜇𝐺 = is a global mean or average intensity of the entire image we can use the normalized, dimensionless metric to assess the "goodness" of the threshold at level (t)[28]; 𝜂 = 𝜎𝐵 2 𝜎𝐺 2 (10) where; (𝝈𝑮 𝟐 )= global variance (the variance in intensity of all pixels in image) 𝜂 = dimensionless metric (𝜎𝐵 2) = between-class variance the global variance and it is given in equation below [10]; 𝜎𝐺 2 = ∑ (𝑖 − 𝜇𝐺 ) 2𝑝𝑖 𝐿−1 𝑖=0 (11) and between-class variance (𝜎𝐵 2) is given in equation below; 𝜎𝐵 2 = 𝑃1(𝜇1 − 𝜇𝐺 ) 2 + 𝑃2(𝜇2 − 𝜇𝐺 ) 2 (12) equation (12) can also be written as; 𝜎𝐵 2(𝑇) = 𝑃1 𝑃2[𝜇1 − 𝜇2] 2 (13) eq. (13) showed that the 𝜎𝐵 2 will be larger whenever the two means (𝜇1) and (𝜇2) are farther from each other, demonstrating that (between-class variance) separability measure between classes. since (𝜎𝐺 2) is constant for a given image; therefore the (𝜂)is a measure of separability also, and maximizing this dimensionless metric is equivalent to maximizing (𝜎𝐵 2). note that eq. (10) assumes implicitly that (𝜎𝐺 2 > 0). this variance can only be zero if all intensity levels in the image are the same, which implies that only one class of pixels exists. this, in turn, means that (𝜂 = 0) for a constant image since separability of single class from itself is zero. the final results yield when (t)reintroduced again: 𝜂(𝑇) = 𝜎𝐵 2 (𝑇) 𝜎𝐺 2 (14) and 𝜎𝐵 2(𝑇) = 𝑃1(𝑇)[(𝜇1(𝑇) − 𝜇𝐺 )] 2 + 𝑃2(𝑇) [(𝜇2(𝑇) − 𝜇𝐺 )] 2 (15) then, the best threshold value is the, (t*) that maximizes 𝜎𝐵 2(𝑇) : 𝜎𝐵 2(𝑇∗) = 𝑚𝑎𝑥0≤𝑇≤𝐿−1𝜎𝐵 2(𝑇) (16) otsu's algorithm also is defined as a weighted sum of the two classes' variances [10]: 𝜎𝑊 2 = 𝑃1(𝑇) 𝜎1 2(𝑇) + 𝑃2(𝑇)𝜎2 2(𝑇) (17) where: weights (𝑷𝟏) and (𝑷𝟐) are the probabilities of the background (class c1) and foreground(class c2) classes respectively, separated by a threshold (t) are stated previously. while𝝈𝟏 𝟐(𝑇)is the variance of the pixels in the background (below threshold), 𝝈𝟐 𝟐(𝑇) is the variance of the pixels in the foreground (above threshold), given in equations below; 𝜎1 2(𝑇) = 1 𝑃1(𝑇) ∑ [𝑖 − 𝜇1(𝑇)] 2 𝑝(𝑖) 𝑇𝑖=0 (18) 𝜎2 2(𝑇) = 1 𝑃2(𝑇) ∑ [𝑖 − 𝜇2(𝑇)] 2 𝑝(𝑖) 𝐿−1𝑖=𝑇+1 (19) and 𝝈𝑾 𝟐 (𝑻) is within-class variance. then, the best threshold value is the, t* that minimizes𝜎𝐵 2(𝑇) ; 𝜎𝑊 2 (𝑇∗) = 𝑚𝑖𝑛0≤𝑇≤𝐿−1𝜎𝑤 2 (𝑇) (20) y. j. tawfeeq and j.a. al-sudani / iraqi journal of chemical and petroleum engineering 21,3 (2020) 57 66 60 for two classes, otsu showed that minimizing the within-class variance is the same as maximizing withinclass variance, in another meaning; subtracting withinclass variance from the total variance get something called the between-class varianceσb 2 (t) [29].the best threshold using the otsu method is the one maximizing overall between classes variance or minimizing overall within-class variance. in fig. 1-a there is a simple bimodal distribution with two homogeneous classes where the threshold value (t) can be easily determined. if there is no valley one as shown in fig. 1-b the method of determining threshold value (t) is minimizing the total variance within both classes or maximizes the overall variance between both classes. the best threshold is maximizing the between classes variance or, contrariwise, minimizing the within-class variance[30-31]. fig. 1. typical image histogram show (1-a) simple bimodal distribution (1-b) no-bimodal distribution in this study, otsu algorithm implementation started with converting the color image to grayscale image and plotting the input image's normalized histogram. according to the threshold value, the histogram pixels are separated into two clusters or class. the cumulative sums and the cumulative means for each class are calculated using eq. (3) through (6). the total (global) intensity means it is calculated using eq. (7). the between-class variance 𝜎𝐵 2(𝑇) is calculated using eq. (13), where the farther apart the means, the larger will be 𝜎𝐵 2(𝑇). the maximum"between-class variance 𝜎𝐵 2(𝑇) is set as an optimum otsu threshold value (t*). when the maximum is not unique, the values corresponding to the detected maximum can be (t *) averaged. finally, optimum separability measure, (𝜂 ∗)at (t = t*) is obtained using eq. (14). the separability is a measure of how easily separable the classes are. a uniform distribution is (0), and a clear, bimodal is (1). 3calculations and analysis 3.1. otsu thresholding implementation the objective of this section is to introduce and apply the binary segmentation algorithm of otsu on the samples under study. matlab code created which automatically segment and determine the digital rock porosity, based on the otsu's thresholding algorithm using the following main matlab code; as a first step, a pixel-value histogram using matlab image analysis toolbox plotted for each digital image, as shown in fig. (2), because the used image type is an 8-bit image, there were (256) possible pixel values. the histogram height with 256 bins is calculated, where each bin's height is equal to the number of pixels with that pixel value from (0) to (255). for each given image, the probability of the pixel value (i) calculated using eq. (3) by separating the height of bin by the complete number of pixels in the histogram. since the goal is to maximize between-class variance, each class mean, global intensity means and variances of both classes calculated using eq. (5), (7) and (15), respectively. fig. 2. pixel-value image histogram for sample no.(7) function level = otsu(histogramcounts) total = sum(histogramcounts); % total number of pixels in the image %% otsu automatic thresholding top = 256; sumb = 0; wb = 0; maximum = 0.0; sum1 = dot(0:top-1, histogramcounts); for ii = 1:top wf = total wb; if wb > 0 && wf > 0 mf = (sum1 sumb) / wf; val = wb * wf * ((sumb / wb) mf) * ((sumb / wb) mf); if ( val >= maximum ) level = ii; maximum = val; end end wb = wb + histogramcounts(ii); sumb = sumb + (ii-1) * histogramcounts(ii); end end y. j. tawfeeq and j.a. al-sudani / iraqi journal of chemical and petroleum engineering 21,3 (2020) 57 66 61 finally, the otsu threshold value (tb) obtained as a value of for which 𝜎𝐵 2(𝑇) is maximum. for not unique maximum threshold value, the otsu threshold value (tb) obtained by averaging the values of corresponding to the various maxima detected. additionally, the separability measure, 𝜼 ∗ was calculated using eq. (14) at (t = tb). it is sufficient to increase between class variance eq. (13) this will decrease within-class variance too. therefore, only the "between-class variance” calculated for each threshold and picked the threshold that maximizes the variance. depending on each microscopic image quality, otsu's algorithm was run several times for better results. the matlab function (im2bw) is used to convert an intensity image to a binary image. the binary image level which is a normalized intensity value that lies in the range (0, 1) was calculated depending on optimal threshold value (tb). the results of threshold, class variance and separability criterion are for twenty-two used samples are listed in the table 1. the results of otsu thresholding are exposed in fig. 3 for some analyzed samples, for example. it can be observed that the threshold of the otsu has divided the digital image into two levels: white (porous) and black (matrix) background. 3.2. porosity and pore space characteristics determination a digital image comprises pixels, which are building blocks of an image. core samples image used in this study were cropped at (637x478) pixels; hence the total number of pixels in a sample is 304486 pixels. core thin section samples consist of empty pore space filled with the blue liquid epoxy and solid grains comprising of different minerals colors, as shown in fig. 3. the definition of porosity from image analysis can be written in pixels term as [32-33]; 𝑃𝑜𝑟𝑜𝑠𝑖𝑡𝑦 (𝐼𝑚𝑎𝑔𝑒) = ∑ 𝑝𝑖𝑥𝑒𝑙𝑠 𝑖𝑛 𝑝𝑜𝑟𝑒 𝑠𝑝𝑎𝑐𝑒 𝑇𝑜𝑡𝑎𝑙 𝑛𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑝𝑖𝑥𝑒𝑙𝑠 (21) table 1. results of otsu thresholding method parameters coreid threshold separability criterion between class variance level global mean 7 116 0.738 2014.095 0.453 77.549 19 70 0.655 857.701 0.273 51.699 23 82 0.673 977.849 0.32 60.731 24 98 0.651 352.521 0.383 99.982 25 130 0.6607 1290.457 0.508 108.541 27 60 0.692 901.321 0.234 31.857 30 63 0.642 843.274 0.246 47.497 31 79 0.665 1249.349 0.309 51.538 35 94 0.797 1968.251 0.367 52.731 36 83 0.751 1673.708 0.324 55.031 37 108 0.794 2587.521 0.422 58.826 38 67 0.621 615.282 0.262 49.961 39 117 0.814 2494.852 0.457 60.336 45 65 0.614 628.847 0.254 47.842 46 79 0.639 652.216 0.309 48.881 47 82 0.640 1128.102 0.32 48.569 48 55 0.604 280.360 0.215 35.338 49 113 0.838 2917.877 0.441 56.905 50 109 0.473 321.355 0.426 108.324 51 71 0.617 564.410 0.277 52.768 52 67 0.620 554.612 0.262 42.295 53 64 0.5693 443.973 0.25 40.040 porosity also defined in terms of pore sizes as micro and macropores. core thin section samples used in the current study were scanned with optical microscopy having a pixel resolution of (10 𝜇m). substantial porosity may be residing in pore sizes less than (10 𝜇m), i.e. sub-resolution pores. such subresolution pores were visually observe-able on thinsection images but with a mixed response of clay-silt matrix and porosity. in the current study, sub-resolution pores are defined as (micro pores), and pore sizes larger than (10 𝜇m) is defined as (macro pores). a subjective adjustment factor was used to extract matrix effect from sub-resolution pores as [25]; 𝜑𝑖𝑚𝑎𝑔𝑒 = 𝐴 ∗ 𝜑𝑚𝑖𝑐𝑟𝑜 + 𝜑𝑚𝑎𝑐𝑟𝑜 = 𝜑𝑡𝑜𝑡𝑎𝑙 (22) where: 𝜑𝑖𝑚𝑎𝑔𝑒 = porosity derived from image analysis 𝜑𝑚𝑖𝑐𝑟𝑜 = microporosity derived from image analysis 𝜑𝑚𝑎𝑐𝑟𝑜 = macroporosity derived from image analysis 𝜑𝑡𝑜𝑡𝑎𝑙 = total porosity derived from image analysis ain = adjustment factor (between 0 and 1) to remove matrix effect from sub-resolution pores. as a pixel representing pore size of less than 10 𝜇m may consist of both a grain and a pore. ф𝑚𝑖𝑐𝑟𝑜 is micro pores porosity, and ф𝑚𝑎𝑐𝑟𝑜 is macro pores porosity. microporosity was adjusted by the factor (𝐴 = 0.75) to exclude matrix effect from micropores, and image porosity is calculated using equation (22). the results of image porosity obtained by otsu's thresholding techniques are listed in the table 2 with the comparison with core porosity. fig. 4 shows a comparison of porosity obtained otsu's thresholding techniques vs core porosity. the task of digital rock analysis needs to be quantitatively measured in an area of interest, whether it is pores or grains, extracted from a digital rock image. the extracted objects are binary objects, where interest object with object label map is presented. binary objects characteristically interpreted to get a value of (1), and the residual pixels to reach a value of (0). a binary object can be described by size, shape or distance from other objects. an object's size can be defined by area and perimeter. the area is a suitable measure of the total size. perimeter is mainly ideal for discriminating between objects with simple shapes and those with complex shapes. consider the function in (i, j) described for the object of an (mxn) image: 𝐼𝑛 (𝑖, 𝑗) = { 1 𝑖𝑓 𝐼(𝑖, 𝑗) = 𝑛𝑡ℎ 𝑜𝑏𝑗𝑒𝑐𝑡 𝑛𝑢𝑚𝑏𝑒𝑟 0 𝑜𝑡ℎ𝑒𝑟𝑤𝑖𝑠𝑒 } (23) the area in pixels is then specified by; 𝐴𝑛 = ∑ ∑ 𝐼𝑛 (𝑖, 𝑗) 𝑁−1 𝑗=0 𝑀−1 𝑖=0 (25) y. j. tawfeeq and j.a. al-sudani / iraqi journal of chemical and petroleum engineering 21,3 (2020) 57 66 62 the simple calculation of the perimeter takes from the number of boundary pixels belonging to an object. this achieved thru calculating pixels number with a value of (1) and at least one adjacent pixel of (0). another problem in the measurement of the perimeter is to separate an object's internal and external perimeter (segmented pores). the boundary pixel exact vertex points usually understood to be at the center of that pixel. the boundary pixels location for perimeter measurement yields internal perimeter; external perimeter yields with the boundary of pixels in the background around the object; as shown in fig. 5. fig. 3. original and segmented binary rock images thresholds using otsu method (samples 25,35,39, and 49 respectively from top to bottom) table 2. image porosity analysis results using the otsu thresholding method core id total pores macropores micropores phi_macro phi_micro phi_im phi_core 7 304486 41837 9137 0.137 0.030 0.159 0.182 19 304486 29577 30561 0.097 0.100 0.172 0.193 23 304486 33739 8747 0.110 0.028 0.132 0.145 24 304486 22551 8474 0.074 0.027 0.094 0.095 25 304486 36559 9924 0.120 0.032 0.144 0.158 27 304486 14852 13283 0.048 0.043 0.081 0.085 30 304486 48714 14699 0.159 0.048 0.196 0.207 31 304486 40496 16749 0.132 0.055 0.174 0.199 35 304486 33036 6687 0.108 0.021 0.124 0.142 36 304486 35322 9609 0.116 0.031 0.139 0.144 37 304486 42083 3843 0.138 0.012 0.147 0.184 38 304486 47138 15888 0.154 0.052 0.193 0.212 39 304486 50218 12294 0.164 0.040 0.195 0.217 45 304486 48565 13666 0.159 0.044 0.193 0.213 46 304486 21743 13485 0.071 0.044 0.104 0.147 47 304486 17129 27177 0.056 0.089 0.123 0.147 48 304486 18437 15278 0.060 0.050 0.098 0.17 49 304486 38680 3195 0.127 0.010 0.134 0.167 50 304486 13801 9660 0.045 0.031 0.069 0.12 51 304486 25996 13299 0.085 0.043 0.118 0.128 52 304486 28605 12458 0.093 0.040 0.124 0.139 53 304486 21650 14724 0.071 0.048 0.107 0.156 fig. 4. comparison of image-based total porosity using otsu thresholding method with core porosity the circular equivalent diameter defined as the diameter of a circle with the same area as the region. thus, once the area of the pore measured, the equivalent diameter (deq) calculated as [26]; 𝐷𝑒𝑞 = √ 4𝐴 𝜋 (25) specific surface area or surface to volume ratio is approximated by the ratio of pore perimeter to pore area. perimeter and area of each pore (i) are outputs of binary image analysis as discussed previously. the specific surface area of digital binary rock sample image is written as [26]; y. j. tawfeeq and j.a. al-sudani / iraqi journal of chemical and petroleum engineering 21,3 (2020) 57 66 63 𝑆𝑖 = 𝑃𝑜𝑟𝑒 𝑃𝑒𝑟𝑖𝑚𝑒𝑡𝑒𝑟 𝑃𝑜𝑟𝑒 𝐴𝑟𝑒𝑎 (26) the specific area of the analyzed sample is approximated as the average specific area of all pores. 𝑆 = 1 𝑁 ∑ 𝑆𝑖 (27) the results of image pore space characteristics obtained by otsu's thresholding techniques are listed in the table (3). fig. 5. perimeter measurement by counting the number of object boundary pixels table 3. image pore space characteristics results using otsu thresholding method core id avg. area (µm 2 ) avg. equiv. diameter (µm) avg. perimeter (µm) avg. specific surface area (1/ µm) 7 49.45 3.774 18.355 1.088 19 10.911 2.659 10.927 1.2691 23 31.01 3.412 18.228 1.178 24 28.788 3.754 17.583 1.136 25 42.531 4.403 22.288 1.092 27 25.809 3.131 12.076 1.064 30 32.995 3.413 18.412 1.111 31 24.72 3.364 14.549 1.1028 35 51.983 3.489 19.649 1.201 36 44.861 3.172 15.724 1.185 37 92.241 4.973 26.83 1.077 38 29.816 3.443 17.315 1.140 39 102.234 5.658 27.138 1.009 45 35.332 3.436 18.804 1.169 46 21.252 3.390 13.455 1.137 47 7.144 2.165 6.754 1.249 48 15.916 3.061 11.361 1.138 49 116.055 5.648 26.785 1.004 50 23.206 3.619 14.817 1.101 51 18.550 3.139 13.178 1.181 52 26.980 3.474 15.193 1.134 53 19.365 3.190 12.951 1.1583 3.3. results and discussion in this study, three statistical parameters are considered for the analysis of image porosity resulted from a digital image. these statistical parameters utilized to assess the accuracy of porosity predicted from the digital rock analysis. absolute average percent relative error (aare) used to quantify the average value of the absolute relative deviation of measured porosity value from experimental core porosity data. the standard deviation of the estimated image porosity relative to the experimental values is essential to measure the accuracy of the correlation and used algorithm. the value of standard deviation is usually expressed in percent, and the small value indicates higher accuracy. the purpose of performing the correlation coefficient is to describe the strength of the association between two variables, namely experimental and calculated values. the correlation coefficient (r) expresses the presence or non-presence of a linear interrelationship between the two observed variables. if the linear interrelationship is positive, the correlation coefficient will be a positive number between 0 and 1.0. if, on the other hand, it is negative, the number will be between (0) and (1). the coefficient of determination (r 2 ) is the square of the coefficient of correlation (r) shows percentage variation in the y-axis that described by all x-axis variables collected. it is varied between (0) and (1) with higher values is better. the results of aare, standard deviation, correlation coefficient, and coefficient of determination are 14.66, 0.029, 0.892 and 0.796, respectively. 4discussions and conclusions porosity from image analysis was compared against core porosity to validate the goodness of porosity prediction from image analysis. however, uncertainties associated with both measurements shall be considered as well. porosity from image analysis is limited to pixels resolution of optical microscopy and represents a very small section of the rock sample. core porosity is determined on the 1-inch cylindrical plug while the dimensions of thin section sample are only 35 𝜇m thick with a diameter of 1-inch. the volume investigated is different. studied scanned samples with optical microscopy had a pixel resolution of 10 𝜇m. pore sizes larger than (10 𝜇m) (i.e. macropores) were correctly resolved, but there was a significant quantity of sub-resolution pores (micropores) with mixed response of pore and matrix. a subjective adjustment factor used to take out this matrix effect from micro-pores. this single value of adjustment factor was determined while comparing image porosity against core porosity for all samples. this factor has selected as (0.75) in this study to correct the matrix effect during otsu segmentation method. the suggested value may have worked for the analyzed samples of the current research and can differ in other environments. uncertainty analysis can also be analyzed for porosity from thin section image analysis. y. j. tawfeeq and j.a. al-sudani / iraqi journal of chemical and petroleum engineering 21,3 (2020) 57 66 64 as follows from error analysis results, due to an appropriate choice and capture of blue color using otsu algorithm segmentation, the porosity obtained by image analysis is quite close to the core porosity. the errors are about 14.66% with a standard deviation of about 0.029 and high correlation coefficient of (r = 0.892). furthermore, binary images capture the pore distribution excellently without counting matrix material as pore space. digital thin section image analysis can be considered as an alternate technique to evaluate porosity and pore space rock properties rather than experimental core analysis. histogram thresholding established method had the element of subjectivity in it where the threshold on pixel intensity histogram had to be manually adjusted till the analyst is visually satisfied that pore space adequately captured. this visual analysis was challenging, as optically scanned images used in the current study had a pixel resolution of 10𝜇m/pixel, and there were a significant number of pores with size less than the pixel resolution. in another study, regression equations used to achieve a good correlation of porosity between image analysis and routine core analysis data. these adjustments and regression lost the predictive power of image analysis. otsu clustering introduced as an automatic technique to separate the intensity histogram into two parts and segment the pores from the matrix. thin sections image porosity using the otsu technique showed a good match with core porosity; with the additional benefit, that workflow now automated. moreover, the otsu method can predict threshold values if it desired to make image interpretation with a thresholding technique. in the current study, porosity is the main petro physical property determined from thin section images. for future work, the permeability as a function of porosity and pore space characteristics can be estimated. the predictive power of the otsu method is encouraging, as it can be applied on vastly available drill cuttings as a secondary means of porosity data. however, for the wells where conventional core data is not available or possible, porosity can be determined from thin section images for its integration with well logs interpretation to reduce uncertainties. some limitations to thin section image analysis were also observed. for optically scanned images, pore sizes less than ten𝜇m had a mixed response of matrix and porosity. a subjective but a single adjustment factor was required to remove the matrix effect from such pores for all analyzed samples. this is equally applicable for both automatic and manual thresholding techniques. clustering analyzes porosity from pore filling blue epoxy, i.e., a blue cluster; it was observed that clustering over-estimates porosity if blue color is also present as a matrix color. such a situation will be equally challenging for manual thresholding and hence, can be concluded as a general limitation of thin section image analysis. references [1] r. c. gonzalez and r. e. woods, digital image processing. new jersey: parson, 2008. [2] l. g. shapiro and g. c. stockman, "computer vision. 279-325," ed: new jersey, prentice-hall, isbn 0-13-030796-3, 2001. [3] l. barghout and l. lee, "perceptual information processing system." u.s. patent application 10/618,543, filed march 25, 2004. [4] p. shanthakumar and p. ganesh kumar, "computer aided brain tumor detection system using watershed segmentation techniques", international journal of imaging systems and technology, vol. 25, no. 4, pp. 297-301, 2015. [5] e. b. george and m. karnan, "mr brain image segmentation using bacteria foraging optimization algorithm," international journal of engineering and technology (ijet), vol. 4, pp. 295-301, 2012. [6] j. delmerico, p. david and j. corso, "building facade detection, segmentation, and parameter estimation for mobile robot stereo vision", image and vision computing, vol. 31, no. 11, pp. 1632-1639, 2013. [7] d. l. pham, et al., "current methods in medical image segmentation," annual review of biomedical engineering, vol. 2, pp. 315-337, 2000. [8] m. forouzanfar, n. forghani and m. teshnehlab, "parameter optimization of improved fuzzy c-means clustering algorithm for brain mr image segmentation", engineering applications of artificial intelligence, vol. 23, no. 2, pp. 160-168, 2010. [9] s. kamalakannan, "double-edge detection of radiographic lumbar vertebrae images using pressurized open dgvf snakes," ieee transactions on biomedical engineering, vol. 57, pp. 1325-1334, 2010. [10] n. otsu, "a threshold selection method from graylevel histograms", ieee transactions on systems, man, and cybernetics, vol. 9, no. 1, pp. 62-66, 1979. [11] o. wirjadi, "survey of 3d image segmentation methods," 2007. [12] h. mobahi, s. rao, a. yang, s. sastry and y. ma, "segmentation of natural images by texture and boundary compression", international journal of computer vision, vol. 95, no. 1, pp. 86-98, 2011. [13] md. abu bakr siddique, mohammad mahmudur rahman khan, rezoana bente arif and zahidun ashrafi, "study and observation of the variations of accuracies for handwritten digits recognition with various hidden layers and epochs using neural network algorithm." in 2018 4th international conference on electrical engineering and information & communication technology (iceeict), pp. 118-123. ieee, 2018. http://sdeuoc.ac.in/sites/default/files/sde_videos/digital%20image%20processing%203rd%20ed.%20-%20r.%20gonzalez%2c%20r.%20woods-ilovepdf-compressed.pdf http://sdeuoc.ac.in/sites/default/files/sde_videos/digital%20image%20processing%203rd%20ed.%20-%20r.%20gonzalez%2c%20r.%20woods-ilovepdf-compressed.pdf https://patents.google.com/patent/us20040059754a1/en https://patents.google.com/patent/us20040059754a1/en https://patents.google.com/patent/us20040059754a1/en https://onlinelibrary.wiley.com/doi/full/10.1002/ima.22147 https://onlinelibrary.wiley.com/doi/full/10.1002/ima.22147 https://onlinelibrary.wiley.com/doi/full/10.1002/ima.22147 https://onlinelibrary.wiley.com/doi/full/10.1002/ima.22147 https://onlinelibrary.wiley.com/doi/full/10.1002/ima.22147 http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.411.7411&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.411.7411&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.411.7411&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.411.7411&rep=rep1&type=pdf https://www.sciencedirect.com/science/article/abs/pii/s0262885613001327 https://www.sciencedirect.com/science/article/abs/pii/s0262885613001327 https://www.sciencedirect.com/science/article/abs/pii/s0262885613001327 https://www.sciencedirect.com/science/article/abs/pii/s0262885613001327 https://www.sciencedirect.com/science/article/abs/pii/s0262885613001327 https://www.annualreviews.org/doi/abs/10.1146/annurev.bioeng.2.1.315 https://www.annualreviews.org/doi/abs/10.1146/annurev.bioeng.2.1.315 https://www.annualreviews.org/doi/abs/10.1146/annurev.bioeng.2.1.315 https://www.sciencedirect.com/science/article/abs/pii/s095219760900150x https://www.sciencedirect.com/science/article/abs/pii/s095219760900150x https://www.sciencedirect.com/science/article/abs/pii/s095219760900150x https://www.sciencedirect.com/science/article/abs/pii/s095219760900150x https://www.sciencedirect.com/science/article/abs/pii/s095219760900150x https://ieeexplore.ieee.org/abstract/document/5415616 https://ieeexplore.ieee.org/abstract/document/5415616 https://ieeexplore.ieee.org/abstract/document/5415616 https://ieeexplore.ieee.org/abstract/document/5415616 https://ieeexplore.ieee.org/abstract/document/5415616 https://cw.fel.cvut.cz/wiki/_media/courses/a6m33bio/otsu.pdf https://cw.fel.cvut.cz/wiki/_media/courses/a6m33bio/otsu.pdf https://cw.fel.cvut.cz/wiki/_media/courses/a6m33bio/otsu.pdf https://kluedo.ub.uni-kl.de/frontdoor/index/index/docid/1978 https://kluedo.ub.uni-kl.de/frontdoor/index/index/docid/1978 https://link.springer.com/article/10.1007/s11263-011-0444-0 https://link.springer.com/article/10.1007/s11263-011-0444-0 https://link.springer.com/article/10.1007/s11263-011-0444-0 https://link.springer.com/article/10.1007/s11263-011-0444-0 https://ieeexplore.ieee.org/abstract/document/8628144 https://ieeexplore.ieee.org/abstract/document/8628144 https://ieeexplore.ieee.org/abstract/document/8628144 https://ieeexplore.ieee.org/abstract/document/8628144 https://ieeexplore.ieee.org/abstract/document/8628144 https://ieeexplore.ieee.org/abstract/document/8628144 https://ieeexplore.ieee.org/abstract/document/8628144 https://ieeexplore.ieee.org/abstract/document/8628144 https://ieeexplore.ieee.org/abstract/document/8628144 y. j. tawfeeq and j.a. al-sudani / iraqi journal of chemical and petroleum engineering 21,3 (2020) 57 66 65 [14] rezoana bente arif, md. abu bakr siddique, mohammad mahmudur rahman khan and mahjabin rahman oishe, "study and observation of the variations of accuracies for handwritten digits recognition with various hidden layers and epochs using convolutional neural network." in 2018 4th international conference on electrical engineering and information & communication technology (iceeict), pp. 112-117. ieee, 2018. [15] mohammad mahmudur rahman khan, rezoana bente arif, md. abu bakr siddique and mahjabin rahman oishe, "study and observation of the variation of accuracies of knn, svm, lmnn, enn algorithms on eleven different datasets from uci machine learning repository", in 2018 4th international conference on electrical engineering and information & communication technology (ieee ict), 2018, pp. 124-129. [16] m. sezgin and b. sankur, "survey over image thresholding techniques and quantitative performance evaluation", journal of electronic imaging, vol. 13, no. 1, pp. 146-166, 2004. [17] y. zhang and l. wu, "optimal multi-level thresholding based on maximum tsallis entropy via an artificial bee colony approach," entropy, vol. 13, pp. 841-859, 2011. [18] a. dos anjos and h. shahbazkia, "bi-level image thresholding-a fast method", in biosignals (2), 2008, pp. 70-76. [19] p.-s. liao, “a fast algorithm for multi-level thresholding," j. inf. sci. eng., vol. 17, 2001, pp. 713-727. [20] ghassan h. ali, yahya j. tawfeeq, and mohammed y. najmuldeen, “comparative estimation of water saturation in a carbonate reservoir: a case study of northern iraq”, periodicals of engineering and natural sciences, nol. 7, no. 4, pp.1743-1754, 2019. [21] mohammed y. najmuldeen, ali a. fadhil, and yahya j. tawfeeq, “petrophysical characterization of the tertiary oil reservoir, northern iraq”, periodicals of engineering and natural sciences, issn 2303-4521, vol. 8, no. 2, 2020. [22] karrar hayder jassim and jalal a. al-sudani. " reevaluation of petro physical properties in yammama formation at nasiriya field”. iraqi journal of chemical and petroleum engineering, vol.20 no.3, 2019, pp. 59 – 66. [23] yahya j. tawfeeq, mohammed y. najmuldeen and ghassan h. ali, “optimal statistical method to predict subsurface formation permeability depending on open hole wireline logging data: a comparative study”, periodicals of engineering and natural sciences, issn 2303-4521, vol. 8, no. 2, 2020. [24] sara s. zughar, ahmad a. ramadhan, ahmed k. jaber, "petrophysical properties of an iraqi carbonate reservoir using well log evaluation," iraqi journal of chemical and petroleum engineering, vol.21, no.1, pp. 53 – 59,2020. [25] fens, t.w., “petrophysical properties from small rock samples using image analysis techniques”, ph.d, delft university of technology, 2000. [26] zerabruk, b.t., nermoen, a., nadeau, p.h., “digital image analysis for petrophysical characterization”, m.sc., university of stavanger, 2017. [27] sonka, hlavac and boyle, “digital image processing and computer vision”, india edition, cengage learning, 2007. [28] k. fukunaga, introduction to statistical pattern recognition. elsevier, 2013. pp. 260-267. [29] j. gong, l. li, and w. chen, “fast recursive algorithms for two-dimensional thresholding,” pattern recognition, vol. 31, no. 3, pp. 295–300, 1998. [30] zhang, jun and hu jinglu, "image segmentation based on 2d otsu method with histogram analysis", computer science and software engineering, 2008 international conference on. 6: 105–108. [31] zhu, ningbo and wang, gang and yang, gaobo and dai, weiming, "a fast 2d otsu thresholding algorithm based on improved histogram", pattern recognition, 2009. ccpr 2009, chinese conference on: 1–5. [32] varfolomeev, i., yakimchuk, i., denisenko, a., khasanov, i., osinceva, n., rahmattulina, a., “integrated study of thin sections: optical petrography and electron microscopy”, spe 182071, 2016. [33] lawrence, m., jiang, y., "porosity, pore size distribution, micro-structure." in bio-aggregates based building materials, pp. 39-71. springer, dordrecht, 2017 https://ieeexplore.ieee.org/abstract/document/8628078 https://ieeexplore.ieee.org/abstract/document/8628078 https://ieeexplore.ieee.org/abstract/document/8628078 https://ieeexplore.ieee.org/abstract/document/8628078 https://ieeexplore.ieee.org/abstract/document/8628078 https://ieeexplore.ieee.org/abstract/document/8628078 https://ieeexplore.ieee.org/abstract/document/8628078 https://ieeexplore.ieee.org/abstract/document/8628078 https://ieeexplore.ieee.org/abstract/document/8628078 https://ieeexplore.ieee.org/abstract/document/8628041 https://ieeexplore.ieee.org/abstract/document/8628041 https://ieeexplore.ieee.org/abstract/document/8628041 https://ieeexplore.ieee.org/abstract/document/8628041 https://ieeexplore.ieee.org/abstract/document/8628041 https://ieeexplore.ieee.org/abstract/document/8628041 https://ieeexplore.ieee.org/abstract/document/8628041 https://ieeexplore.ieee.org/abstract/document/8628041 https://ieeexplore.ieee.org/abstract/document/8628041 https://www.spiedigitallibrary.org/journalissue/download?fulldoi=10.1117%2f1.1631315&sso=1 https://www.spiedigitallibrary.org/journalissue/download?fulldoi=10.1117%2f1.1631315&sso=1 https://www.spiedigitallibrary.org/journalissue/download?fulldoi=10.1117%2f1.1631315&sso=1 https://www.spiedigitallibrary.org/journalissue/download?fulldoi=10.1117%2f1.1631315&sso=1 https://www.mdpi.com/1099-4300/13/4/841 https://www.mdpi.com/1099-4300/13/4/841 https://www.mdpi.com/1099-4300/13/4/841 https://www.mdpi.com/1099-4300/13/4/841 https://www.scitepress.org/papers/2008/10643/10643.pdf https://www.scitepress.org/papers/2008/10643/10643.pdf https://www.scitepress.org/papers/2008/10643/10643.pdf https://www.iis.sinica.edu.tw/zh/error/404.html https://www.iis.sinica.edu.tw/zh/error/404.html https://www.iis.sinica.edu.tw/zh/error/404.html http://pen.ius.edu.ba/index.php/pen/article/view/917 http://pen.ius.edu.ba/index.php/pen/article/view/917 http://pen.ius.edu.ba/index.php/pen/article/view/917 http://pen.ius.edu.ba/index.php/pen/article/view/917 http://pen.ius.edu.ba/index.php/pen/article/view/917 http://pen.ius.edu.ba/index.php/pen/article/view/1303 http://pen.ius.edu.ba/index.php/pen/article/view/1303 http://pen.ius.edu.ba/index.php/pen/article/view/1303 http://pen.ius.edu.ba/index.php/pen/article/view/1303 http://pen.ius.edu.ba/index.php/pen/article/view/1303 https://doi.org/10.31699/ijcpe.2019.3.8 https://doi.org/10.31699/ijcpe.2019.3.8 https://doi.org/10.31699/ijcpe.2019.3.8 https://doi.org/10.31699/ijcpe.2019.3.8 https://doi.org/10.31699/ijcpe.2019.3.8 http://pen.ius.edu.ba/index.php/pen/article/view/1306 http://pen.ius.edu.ba/index.php/pen/article/view/1306 http://pen.ius.edu.ba/index.php/pen/article/view/1306 http://pen.ius.edu.ba/index.php/pen/article/view/1306 http://pen.ius.edu.ba/index.php/pen/article/view/1306 http://pen.ius.edu.ba/index.php/pen/article/view/1306 https://doi.org/10.31699/ijcpe.2020.1.8 https://doi.org/10.31699/ijcpe.2020.1.8 https://doi.org/10.31699/ijcpe.2020.1.8 https://doi.org/10.31699/ijcpe.2020.1.8 https://doi.org/10.31699/ijcpe.2020.1.8 https://www.narcis.nl/publication/recordid/oai:tudelft.nl:uuid:d5f7947c-15b4-455e-9cef-99badf41c6ed https://www.narcis.nl/publication/recordid/oai:tudelft.nl:uuid:d5f7947c-15b4-455e-9cef-99badf41c6ed https://www.narcis.nl/publication/recordid/oai:tudelft.nl:uuid:d5f7947c-15b4-455e-9cef-99badf41c6ed https://books.google.iq/books?hl=en&lr=&id=bijztgjtxbgc&oi=fnd&pg=pp1&dq=introduction+to+statistical+pattern+recognition.+boston&ots=x8cglsjnls&sig=lwyfbjehcwhuo20o21trzbseigs&redir_esc=y#v=onepage&q=introduction%20to%20statistical%20pattern%20recognition.%20boston&f=false https://books.google.iq/books?hl=en&lr=&id=bijztgjtxbgc&oi=fnd&pg=pp1&dq=introduction+to+statistical+pattern+recognition.+boston&ots=x8cglsjnls&sig=lwyfbjehcwhuo20o21trzbseigs&redir_esc=y#v=onepage&q=introduction%20to%20statistical%20pattern%20recognition.%20boston&f=false https://www.sciencedirect.com/science/article/abs/pii/s0031320397000435 https://www.sciencedirect.com/science/article/abs/pii/s0031320397000435 https://www.sciencedirect.com/science/article/abs/pii/s0031320397000435 https://www.sciencedirect.com/science/article/abs/pii/s0031320397000435 https://ieeexplore.ieee.org/abstract/document/4723207 https://ieeexplore.ieee.org/abstract/document/4723207 https://ieeexplore.ieee.org/abstract/document/4723207 https://ieeexplore.ieee.org/abstract/document/4723207 https://ieeexplore.ieee.org/abstract/document/5344078 https://ieeexplore.ieee.org/abstract/document/5344078 https://ieeexplore.ieee.org/abstract/document/5344078 https://ieeexplore.ieee.org/abstract/document/5344078 https://www.onepetro.org/conference-paper/spe-182071-ru https://www.onepetro.org/conference-paper/spe-182071-ru https://www.onepetro.org/conference-paper/spe-182071-ru https://www.onepetro.org/conference-paper/spe-182071-ru https://www.onepetro.org/conference-paper/spe-182071-ru https://link.springer.com/chapter/10.1007/978-94-024-1031-0_2 https://link.springer.com/chapter/10.1007/978-94-024-1031-0_2 https://link.springer.com/chapter/10.1007/978-94-024-1031-0_2 https://link.springer.com/chapter/10.1007/978-94-024-1031-0_2 y. j. tawfeeq and j.a. al-sudani / iraqi journal of chemical and petroleum engineering 21,3 (2020) 57 66 66 باستخدام otsuتحليل مسامية النماذج الصخرية الرقمية باالستناد على تقنيةعتبة الماتالب يحيى جرجيس توفيق وجالل عبد الواحد السوداني سة، جامعة بغداد، بغداد، العراققسم هندسة النفط، كلية الهند الخالصة تلعب المسامية دوًرا أساسًيا في الجيولوجيا وهندسة البترول. وهي تتحكم في تخزين السوائل في طبقات المياه الجوفية وحقول النفط والغاز وتوصيل هيكل المسام للتحكم في تدفق السوائل وانتقالها من خالل تكوينات الخزان. الصخور، يجب قياس بنية المسام ووصفها كميًا. لتحديد العالقات بين المسامية والتخزين والنقل وخصائص حيث يتم فيها حساب مسامية الصور الرقمية باستخدام معالجة الصور يعد امرا مهما لتحليل صخور المكامن الوتينية يستخدم عملية تحويل الصورة الى ابيض واسود حيث وصف المسامية ثنائية األبعاد للعينة. العمليات تستخدم حد قيمة البيكسل لتحويل الصور الملونة والرمادية إلى صور ثنائية. والفكرة هي استيعاب المناطق الزرقاء بالكامل مع المسام وتحويلها إلى اللون األبيض في صورة ثنائية ناتجة. تقدم هذه الدراسة إمكانات م معالجة الصور لتحديد مسامية عينات الصخور الرقمية ثنائية األبعاد في صخور مكامن الكربونية. تم استخدا إنشاء كود ماتالب، والذي يقوم تلقائًيا بتقطيع مسامية الصخور الرقمية وتحديدها، استناًدا إلى خوارزمية عتبة otsu ات مقطع رقيق ثنائي األبعاد لحقل عينة من صخور مكمن الصورة ذ 22. في هذا العمل، تمت دراسة نفط عراقي. تتم معالجة أمثلة صور القسم الرقيق ورقمنتها باستخدام برمجة ماتالب. في الدراسة الحالية، ركزنا للصورة الرقمية. أيضا، تم حساب بعض خصائص الفراغ المسامي، مسامات المايكرو والماكرو على حساب المختبري ائج تحليل الصور الرقمية ثنائية األبعاد بنتائج المسامية من الفحصمثل الحجم والمحيط. تم مقارنة نت لتحديد قوة تقنيات تفسير الصور الرقمية المستخدمة. أظهرت مسامية الصورة الدقيقة المجهرية التي تم حسابها تطابًقا جيًدا مع المسامية المحسوبة من الفحوصات المختبرية. otsuباستخدام تقنية : فيزياء الصخور الرقمية، عتبة أوتسو، صورة المقطع الرقيق، المسامية، مسامات المايكرو، مسامات الماكرو.الدالةلمات الك available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.21 no.4 (december 2020) 49 – 55 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: raad mohammed hasan , email: raadhaji1979@gmail.com, name: ayad a. al-haleem, email: ayadah62@yahoo.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. modifying an equation to predict the asphaltene deposition in the buzurgan oil field raad mohammed hasan and ayad a. al-haleem college of engineeringuniversity of baghdad abstract buzurgan oil field suffers from the phenomenon of asphaltene precipitation. the serious negatives of this phenomenon are the decrease in production caused by clogging of the pores and decrease in permeability and wettability of the reservoir rocks, in addition to the blockages that occur in the pipeline transporting crude oil. the presence of laboratories in the iraqi oil companies helped to conduct the necessary experiments, such as gas chromatography (gc) test to identify the components of crude oil and the percentages of each component, these laboratory results consider the main elements in deriving a new equation called modified colloidal instability index (mcii) equation based on a well-known global equation called colloidal instability index (cii) equation. the modified (mcii) equation is considered an equation compared to the original (cii) equation because both equations mainly depend on the components of the crude oil, but the difference between them lies in the fact that the original equation depends on the crude oil components at the surface conditions, while the new equation relies on the analysis of crude oil to its basic components at reservoir conditions by using (gc) analysis device. the components of the crude oil in the reservoir conditions according to the number of carbon atoms of each component compared with the elements of the original equation, which are (saturates, aromatics, resins, and asphaltene). the new mcii equation helps in predicting the possibility of asphaltene precipitation which can be used and generalized to other iraqi oilfields as it has proven its worth and acceptability in this study. keywords: asphaltene deposition, modified equation, colloidal, precipitation, predict. received on 21/02/2020, accepted on 17/07/2020, published on 30/12/2020 https://doi.org/10.31699/ijcpe.2020.4.6 1introduction asphaltene is considered the heaviest and complex series of hydrocarbons within the crude oil mixture; also it can be defined from its solubility, as it is completely soluble with aromatic solvents like toluene, benzene, or xylene, while it does not dissolve with light paraffinic solvents like as n-heptane or n-pentane [1] one of the most important challenges facing the development of mishrif formation in buzurgan oilfield at present is the asphaltene deposition problem near the wellbore. the most important reasons for the asphaltene deposition in buzurgan oilfield are: ahigh gas-oil ratio (gor) in crude oil components. bthe value of the api is relatively low. the process of determining the conditions of asphaltene precipitation called (asphaltene onset point) (aop) is very complex and depends on several factors within the reservoir [2] a study of asphaltene deposition took great importance in most oil-producing countries, including the oilfields in southern iraq, especially the buzurgan oilfields. in order not to increase this problem, it needs to be prevented before the reservoir or oil formation is damaged and lead to the closure of the well. asphaltene is physically similar to coal as it can precipitate with alkanes, they can be classified as heptane insoluble [3] fig. 1. fig. 1. the physical form of asphaltene [4] http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2020.4.6 r. m. hasan and a. a. al-haleem / iraqi journal of chemical and petroleum engineering 21,4 (2020) 49 55 50 buzurgan oilfield located in southern iraq near the iraqi-iranian border and about (60km) south of amara as shown in fig. 2. from the structural point of view, the buzurgan oilfield is about 40km *7km with a northern and southern dome. the southern dome is shallow at a depth of 850m and covers a larger area. the cretaceous mishrif is considered the most important formation and it mediates two layers, abu khasib formation above mishrif formation and rumila formation below it. the mishrif formation has 7 pay zones which are ma, mb11, mb12, mb21, mb22, mc1, and mc2, the mb21 consider the main pay zone in mishrif formation. the approximate depth of the reservoir is 4000m [4]. fig. 2. location of buzurgan oilfield [4] the calculation of the asphaltene ratio in the hydrocarbons is determined using (saturates, aromatics, resins, and asphaltene) analysis called (sara) analysis. sara test is performed in the laboratory by splitting crude oil into four types of compounds according to their solubility in selected solvents [5]. a more efficient way of modeling asphaltene precipitation as a pure dense phase by dividing the heavy phase into its components in terms of precipitating and non-precipitating components thus making quantitative experiments to find suitable algorithms and numerical correlations [6] a model for predicting phase equilibria of heavy mixtures by using soave-redlich-kwong equation of state, by determining the portion of the heavy crude that can potentially precipitate to form waxes such as asphaltene [7]. the large number of parameters that affect asphaltene precipitation makes it very difficult and challenging to produce and model data fitting without a lot of data inputs and even harder to simulate using programs without data. in this paper, a new scaling model has been developed by incorporating more parameters, such as gor, resin to asphaltene ratio, mole percent, and oil density. this new scaling model has been evaluated with a second set of experiments and the results were very valid in terms of accuracy in predicting the amount of precipitated heavy asphaltene. however, its dependency on many factors makes it very time and effort-consuming in application [8]. the precipitation of asphaltene and wax are the main problems that can cause reduced permeability and even block the formation. four different samples were taken from four malaysian oilfields and were subjected to sara analysis, cii (colloidal instability index), refractive index (ri), and molecular weight. the authors proved that results from mathematical relations derived from experimental data were accurate and predictions were very reliable in terms of forecasting the onset of precipitation [9]. asphaltene precipitation is a very serious problem when it comes to plugging wellbore or reducing formations permeability and also affecting surface facilities negatively. it also affects production negatively. sometimes the production stops as a result of the accumulation of asphaltene. in this paper, the author studies different techniques and modeling approaches and studies the best possible way to come up with a proper understanding of how and why precipitation occurs at a certain pressure and temperature and not in other situations [10]. this study aims to model asphaltene precipitation from laboratory experiments and to come up with a new equation that can help in understanding the tendency of particular crude to have asphaltene problems. however, this model is going to be built from the ground to be adapted to specific reservoir parameters in buzurgan oilfield. in general the aim of this study to investigate the use of a new method that uses the compositional analyses of reservoir fluids instead of using sara ( saturates, aromatics, resins, asphaltene) analysis for crude oil to predict the potential of crude to cause problems of asphaltene. 2methodology this part deals mainly with two tasks. the first task is obtaining the crude oil sample and other data from the desired location to conduct practical experiments for the crude oil sample laboratory. the second task is to find the relationship between laboratory results and the (cii) equation to find a new model that can be used to confirm the possibility of asphaltene deposition as a result of production in the iraqi oilfields. the field data and the crude oil sample were taken from the buzurgan oilfield in southern iraq which was produced from three formations where the mishrif is the main formation and lies between the formation of abu khasib and rumaila. the main average depth of the reservoir is about 4000 meters [4]. the experimental work involves conduction the (gas and liquid chromatography) test on the crude oil sample in the missan oil company laboratories to determine the percentages of hydrocarbons and non-hydrocarbon present in the crude oil sample. r. m. hasan and a. a. al-haleem / iraqi journal of chemical and petroleum engineering 21,4 (2020) 49 55 51 the working principle of the gas chromatography (gc) device, as the name implies, gc uses a carrier gas in the separation, this plays the part of the mobile phase. the carrier gas transports the sample molecules through the gc system, ideally without reacting with the sample or damaging the instrument components. the sample is first introduced into the gas chromatograph (gc). the sample is injected into the gc inlet through a septum which enables the injection of the sample mixture without losing the mobile phase. connected to the inlet is the analytical column a long (80 m), narrow (0.4) mm internal diameter) fused silica or metal tube which contains the stationary phase coated on the inside walls. the analytical column is held in the column oven which is heated during the analysis to elute the less volatile components. the outlet of the column is inserted into the detector which response to the chemical components eluting from the column to produce a signal. the signal is recorded by the acquisition software on a computer to produce a chromatogram fig. 3 explains these steps. fig. 3. a simplified diagram of a gas chromatograph 3experimental work 3.1. gas and liquid chromatography experiment gas and liquid chromatography is a technique used to separate different components of a compound according to their volatility and polarity. for this purpose, a device is called (agilent gc) with two columns is used to identify the compositions of crude oil in the laboratory. the device is fully automated and gives the required results. this device is made up of the following components: 1oven: used to heat the column and the sample injected 2sample injection point 3column 4detector 5carrier gas (hydrogen) 6chart recorder: computer for data acquisition 3.2. calibration of gc device gc device needs periodic calibration to perform the required of separate hydrocarbons to percentages. each compound within the crude oil has a special retention time that responds to the detector in the device. calibration of gc can be done with a sample of crude oil in which the compounds it is known previously. the standard retention time for each component is mainly recorded in the gc programming. 3.3. steps of the experiment 1the sample taken from the reservoir is left within a laboratory temperature (25c o ) until its temperature is equal to the surrounding temperature (laboratory temperature) by leaving it at the laboratory for (3) hours because the temperature of the sample taken from the reservoir is high. 2wait for a few seconds after running a chromatography device to stabilize (stability of the device). 3sample injection: enter a limited amount of the crude oil sample automatically by the (injector) which is located above the heater (oven) and pushbutton entry to inject it. 4temperature control: adjust the temperature at 200℃ by the control panel with a temperature rise rate (30℃/min) before startup the oven. 5the analysis takes about 1 hour and then the results appear on the chromatograph screen. 4new equation formulation 4.1. colloidal instability index equation the cii equation can be formulated depending on experimental data to predict significantly the possibility of asphaltene precipitation. the new equation will reduce the cost and the time required to perform the needed tests to determine the probability of asphaltene deposition. the original equation from which the modified equation is derived is: cii = 𝑆𝑎𝑡𝑢𝑟𝑎𝑡𝑒𝑑+𝐴𝑠𝑝ℎ𝑎𝑙𝑡𝑒𝑛𝑒 𝐴𝑟𝑜𝑚𝑎𝑡𝑖𝑐+𝑅𝑒𝑠𝑖𝑛 (1) [5] the terms of the equations are if cii < 0.7 no asphaltene deposition problems. if cii > 0.9 the asphaltene deposition problems are certain. if 0.9 > cii > 0.7 possible asphaltene deposition problems in this work, a mathematical equation is formulated based on a basic equation known as the cii equation. this basic equation was depended on the fractionate of crude oil into its four parts sara analysis of crude oil. the current equation was modified using hydrocarbon components obtained from the gas chromatography experiment instead of sara analysis as explained earlier. r. m. hasan and a. a. al-haleem / iraqi journal of chemical and petroleum engineering 21,4 (2020) 49 55 52 4.2. modified colloidal instability index equation derivation the cii equation (1) can be modified and developed according to the available parameters to highly appropriate data from the experimental work. this equation is being reformulated and modified to be more suitable for buzurgan oilfield and called mcii, the reliability of this new equation will be discussed later. the cii equation will be the basis for the formulation of this new equation the sara fractions in the cii equation can be replaced by reservoir fluid components obtained from gc analysis table 1 because the sum of these components also represents the total original oil. table 1. compositional analysis by gc [11] component separator gas molar separator liquid molar % reservoir fluid molar % n2 1.03 0.09 0.63 co2 6.06 0.53 3.71 h2s 1.06 0.32 0.72 rsh 0.28 0.03 0.2 c1 61.47 2.59 36.43 c2 16.01 2.94 10.45 c3 8.44 3.77 6.45 i-c4 1.01 0.8 0.92 n-c4 2.7 3.28 2.95 i-c5 0.66 1.91 1.19 n-c5 0.67 2.83 1.59 c6 0.49 6.45 3.02 c7 0.12 7.33 3.19 c8 6.45 2.74 c9 5.69 2.42 c10 5.25 2.23 c11 5.25 2.23 c12+ 44.49 18.93 total density 1.074 kg/m3 936.638 kg/m3 1061.984 kg/m3 total molecular weight 25.53 250.52 124.86 density c12+ 979.54 m.w c12 + 467.43 a statistical representation of gc analysis shows the different compositions of crude oil with their concentration values. to match this comparison, each fraction of (sara) must be compared with the corresponding components of laboratory tests as shown in table 2. table 2. comparison of hydrocarbon components with corresponding sara fractions name components corresponding sara light components c1-c5 aromatics medium components c6-c8 saturates heavy components c9 + asphaltene non-hydrocarbon co2,n2,h2s,etc resins this comparison doesn't represent the real values of the (sara) fractions but is approximate values intended to formulate the new equation as the asphaltene the heaviest hydrocarbons and aromatics are the lightest and between them the saturated, while resins in this comparison represent by non-hydrocarbon components. the second part in modifying this equation, which is the most important part, it is necessary to take into consideration the different reservoir conditions on which the new equation is based and the surface conditions on which the original equation is based, and the physical and chemical changes that occur on the components of the crude oil as a result of the pressure difference. physically, most of the light components in the reservoir as a result of high pressure become in an unstable condensed liquid state within the crude oil solution, and when the pressure drops these components become more active for movement and liberation of production, unlike the heavy components that are less active for production. chemically, the light and medium components are interacting and homogeneous with the heavy components at the reservoir pressure, and when the pressure drops these components are separated leaving the heavy components to flocculate inside the reservoir and therefore the product of the heavy components is few compared to the remainder inside the reservoir. therefore, the mcii equation is written in the following formula: mcii = 𝐿𝑐+𝑁𝑐 𝐻𝑐+𝑀𝑐 (2) lc = light component mole % hc = heavy components mole % mc = medium components mole % nc = nonhydrocarbon components mole % this does not mean flipping the equation but rather flipping the elements of the equation only. it is clear from the study of physical and chemical effects on the crude oil in the two different conditions that the percentage of light components in the reservoir is much less than the ratio that was produced, in contrast to the heavy and flocculating components, so the ratio of heavy components in the reservoir is more than that produced on the surface. table 3 and table 4 explain how the percentages of each component are calculated and used in the modified equation. r. m. hasan and a. a. al-haleem / iraqi journal of chemical and petroleum engineering 21,4 (2020) 49 55 53 table 3. different hydrocarbon components corresponding to sara analysis components reservoir fluid mole% molar weight n2 0.63 28.02 non-hydrocarbons components nc co2 3.71 44.01 h2s 0.72 34.08 rsh 0.2 c1 36.43 16.04 light hydrocarbons components lc c2 10.45 30.07 c3 6.46 44.09 i-c4 0.92 58.12 n-c4 2.95 58.12 i-c5 1.19 72.15 n-c5 1.59 72.15 c6 3.02 85.5 medium hydrocarbons components mc c7 3.19 95.6 c8 2.74 107.4 c9 2.42 heavy hydrocarbons components hc c10 + 23.39 269.5 table 4. summation result of different hydrocarbons name of the fraction sum of the components % components light hydrocarbons lc 59.98 component medium hydrocarbons mc 8.95 components heavy hydrocarbons hc 25.81 components non-hydrocarbons nc 5.26 total 100% applying the mcii equation 𝑀𝐶𝐼𝐼 = 𝐿𝑐+𝑁𝑐 𝑀𝑐+𝐻𝑐 (2) 𝑀𝐶𝐼𝐼 = 59.98+5.26 25.81+8.95 = 1.89 if mcii  0.7 no asphaltene problem. if mcii  0.9 the asphaltene problem is certain. if 0.7  mcii  0.9 possible asphaltene problem. note: conditions of mcii taken from original cii equation. the obtained result from mcii = 1.89 confirms the occurrence of asphaltene deposition as a result of continued production. 4.3. evidence on the reliability of the new equation the reliability of this equation and its wider applicability in iraq are discussed as follow: mcii equation was applied using real data obtained from one of northern iraq oilfield that suffers from the asphaltene deposition problem [12], the results support the validity of this equation as shown in table 5 and table 6. table 5. gas chromatography results [12] component recombined mole% molar weight nitrogen 0.316 28.02 carbon dioxide 2.073 44.01 hydrogen sulfide 15.354 34.08 methane 40.986 16.04 ethane 6.941 30.07 propane 4.452 44.09 iso-butane 0.868 1 n-butane 2.573 58.12 neo pentane 0.019 72.15 iso-pentane 1.115 72.15 n-pentane 1.596 72.15 hexane c6 2.640 85.5 heptane c7 2.538 95.6 octane c8 2.616 107.4 nonanes c9 2.219 119.4 decane plus 13.694 269.5 table 6. summation result of different hydrocarbons name of the fraction sum of the components % light hydrocarbons (lc) 58.55 medium hydrocarbons (mc) 7.794 heavy hydrocarbons (hc) 15.914 nonhydrocarbons (nc) 17.743 total 100% by applying the mcii equation 𝑀𝐶𝐼𝐼 = 𝑁𝑐+𝐿𝑐 𝑀𝑐+𝐻𝑐 (3) 𝑀𝐶𝐼𝐼 = 17.743+58.55 7.794+15.914 = 3.218  mcii  0.9 the value of mcii also confirms the matching problem of asphaltene precipitation in that oilfield. the second step in the proof of the reliability of the mcii equation can be done using the plot of de boer [13], which is considered to be a commonly used equation. held de boer and his colleague's laboratory analysis and theoretical work for different crude oils sample around the world and invented the versatile plot fig(4), which many researchers still rely on because the plot was based on the analysis of many oilfields sample under reservoir conditions. r. m. hasan and a. a. al-haleem / iraqi journal of chemical and petroleum engineering 21,4 (2020) 49 55 54 fig. 4. de boers plot for asphaltene problem prediction [13] by using reservoir pressure (4) = 6300 psi, bubble point pressure = 3220 psi, and fluid density of buzurgan oilfield = 0.73 gm/cc, the result indicated that there is a problem of asphaltene deposition in the buzurgan oilfield. in general, it can be said that the derived equation mcii has good reliability and can be used in other iraqi oilfields. just conducting a component analysis indicates the probability of precipitation problem, as it is noticeable that the ratios of light components in crude oil are high and this means that the gor is high. 5conclusions through this study the following conclusions are listed: 1the modified equation showed that mcii= 1.89, this value is greater than 0.9 which means that there is an actual problem of asphaltene deposition in the buzurgan oilfield. 2the present study helps to find a suitable strategy to treat the asphaltene deposition problem in the buzurgan oilfield. 3given the possibility of applying this equation to two oil fields, one in northern iraq and the other in the south, the likelihood of its successful application in other iraqi oil fields that may need some minor modifications. nomenclatures api: american petroleum institute cii: colloidal instability index gc: gas chromatography gor: gas oil ratio mcii: modified colloidal instability index sara: saturates, aromatics, resins, asphaltenes pb: bubble point pressure vle: vapor liquid-equilibrium ri: refractive index bhp: bottom hole pressure bht: bottom hole temperature bhs: bottom hole sample pvt: pressure volume temperature aop: asphaltene onset pressure references [1] wang, j., x., buckley, j.s., burke, n.a,& creek, j.l. (2003,january1). anticipating asphaltene problems offshore-a practical approach. offshore technology conference. [2] jamaluddin, a.k.m, j. creek, c.s. kabir, j.d. mcfadden, d.d,cruz, m.t. joseph ,n. joshi, b.ross. 2001. a comparison of various laboratory techniques to measure thermodynamic asphaltene instability . in.spe-72154-ms. kuala lumpur , malaysia : society of petroleum engineers . [3] thawer, r., nicoll, d.c.a,&dick,g.(1990,november 1) asphaltene deposition in production facilities .society of petroleum engineers . [4] report on the fields operation authority in missan oil company. (2019 april 19). asphaltene background, (planning and followup board no. 782 on 16 april 2019). [5] hirsch berg, a., de jong, l.n.j., schipper ,b.a.,& meijer, j.g.(1984,june1). influence of temperature and pressure on asphaltene flocculation . society of petroleum engineers . [6] nghiem, l. x., hassam, m. s., nutakki, r., & george, a. e. d. (1993, january 1). efficient modelling of asphaltene precipitation. society of petroleum engineers. [7] pedersen, k. s. (1995, february 1). prediction of cloud point temperatures and amount of wax precipitation. society of petroleum engineers. doi:10.2118/27629-pa petroleum science,” amsterdam, 2000. [8] bagheri, m. b., mirzabozorg, a., kharrat, r., dastkhan, z., ghotbi, c., & abedi, j. (2009, january 1). developing a new scaling equation for modelling of asphaltene precipitation. petroleum society of canada. [9] sulaimon, a. a., & govindasamy, k. (2015, october 20). "new correlation for predicting asphaltene deposition". society of petroleum engineers. [10] al-qasim, a., & bubshait, a. (2017, april 23). asphaltenes: what do we know so far. society of petroleum engineers. [11] laboratory department, field operation department fod. missan oil company(2019 april), (planning and followup board no. 782 on 16 april 2019). [12] dana, m. khidhir m.sc. thesis title '' a study of asphaltene precipitation problem in some wells in krg '', university of kurdistan-hawler (2019). [13] de boer, r.b., leer looyer, k., eigner, m.r.p.,& van bergen , a.r.d.(1995,february1)."screening of crude oils for asphaltene precipitation: theory , practice , and the selection of inhibitors" . society of petroleum engineers https://www.onepetro.org/conference-paper/otc-15254-ms https://www.onepetro.org/conference-paper/otc-15254-ms https://www.onepetro.org/conference-paper/otc-15254-ms https://www.onepetro.org/conference-paper/otc-15254-ms https://www.onepetro.org/conference-paper/spe-72154-ms https://www.onepetro.org/conference-paper/spe-72154-ms https://www.onepetro.org/conference-paper/spe-72154-ms https://www.onepetro.org/conference-paper/spe-72154-ms https://www.onepetro.org/conference-paper/spe-72154-ms https://www.onepetro.org/conference-paper/spe-72154-ms https://www.onepetro.org/journal-paper/spe-18473-pa https://www.onepetro.org/journal-paper/spe-18473-pa https://www.onepetro.org/journal-paper/spe-18473-pa https://www.onepetro.org/journal-paper/spe-11202-pa https://www.onepetro.org/journal-paper/spe-11202-pa https://www.onepetro.org/journal-paper/spe-11202-pa https://www.onepetro.org/journal-paper/spe-11202-pa https://www.onepetro.org/conference-paper/spe-26642-ms https://www.onepetro.org/conference-paper/spe-26642-ms https://www.onepetro.org/conference-paper/spe-26642-ms https://www.onepetro.org/conference-paper/spe-26642-ms https://www.onepetro.org/journal-paper/spe-27629-pa https://www.onepetro.org/journal-paper/spe-27629-pa https://www.onepetro.org/journal-paper/spe-27629-pa https://www.onepetro.org/journal-paper/spe-27629-pa https://www.onepetro.org/journal-paper/spe-27629-pa https://www.onepetro.org/conference-paper/petsoc-2009-039 https://www.onepetro.org/conference-paper/petsoc-2009-039 https://www.onepetro.org/conference-paper/petsoc-2009-039 https://www.onepetro.org/conference-paper/petsoc-2009-039 https://www.onepetro.org/conference-paper/petsoc-2009-039 https://www.onepetro.org/conference-paper/spe-176436-ms https://www.onepetro.org/conference-paper/spe-176436-ms https://www.onepetro.org/conference-paper/spe-176436-ms https://asmedigitalcollection.asme.org/omae/proceedings-abstract/omae2017/57762/v008t11a019/282467 https://asmedigitalcollection.asme.org/omae/proceedings-abstract/omae2017/57762/v008t11a019/282467 https://asmedigitalcollection.asme.org/omae/proceedings-abstract/omae2017/57762/v008t11a019/282467 https://www.onepetro.org/journal-paper/spe-24987-pa https://www.onepetro.org/journal-paper/spe-24987-pa https://www.onepetro.org/journal-paper/spe-24987-pa https://www.onepetro.org/journal-paper/spe-24987-pa https://www.onepetro.org/journal-paper/spe-24987-pa https://www.onepetro.org/journal-paper/spe-24987-pa r. m. hasan and a. a. al-haleem / iraqi journal of chemical and petroleum engineering 21,4 (2020) 49 55 55 تحديث معادلة للتنبؤ بترسب االسفلت في حقل بزركان النفطي اياد عبد الحليمو رعد محمد حسن النفط /قسم هندسةالهندسةجامعة بغداد/كلية الخالصة يواجه حقل بزركان النفطي من مشكلة ترسب االسفلت، السلبيات الخطيرة لهذه الظاهرة تتمثل بانخفاض االنتاج الناجم عن انسداد المسامات وتقليل النفاذية والتبللية للصخور المكمنية باالضافة الى االنسدادات التي ت النفط العراقية ساعدت على إجراء تحصل في االنابيب والمعدات السطحية. إن وجود المختبرات في شركا رف على نسب مكونات النفط للتع فحص الطيف اللوني للغاز هذه الدراسة مثل إلتمامالفحوصات الضرورية )مؤشر عدم االستقرار النتائج المختبرية اساس لتحديث معادلة عالمية موجودة اساسا تدعى ث تعتبريالخام ح . مؤشر عدم االستقرار الغروي المستحدث((ى تسم ةالمحدث ةوالمعادل )الغروي يعتبر المعادلة الجديدة معادلة مقارنة للمعادلة االصلية الن كال المعادلتين تعتمدان على مكونات النفط الخام تعتمد على مكونات النفط الخام في الظروف االصلية، لكن االختالف بين المعادلتين تكمن في كون معادلة ي الظروف الجديدة تعتمد على تحليل النفط الخام الى مكوناتها االساسية فالمعادلة السطحية بعد االنتاج ، بينما . فحص الطيف اللوني للغاز المكمنية باستخدام جهاز :والتي هي ))مؤشر عدم االستقرار الغروي تتم مقارنة عناصر معادلة فحص الطيف ( مع مكونات النفط الخام الناتجة عن تحليل )المواد المتشبعة والعطريات والراتنجات واالسفلتين) من كل عنصر من عناصر النفط الخام.( وحسب عدد ذرات الكربون الموجود ضاللوني للغاز حقل بزركان النفطي باالضافة الى ان المعادلة المستحدثة اعطت نتائج مقبولة في التنبؤ بترسب االسفلت في حقل آخر في شمال العراق مما يعني بانها قد تكون قابلة للتطبيق في الحقول العراقية االخرى. تنبؤ.ترسب االسفلتين، المعادلة المستحدثة، الغروائية، ترسيب، :الدالةلكلمات ا available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol. 24 no.2 (june 2023) 31 – 39 eissn: 2618-0707, pissn: 1997-4884 *corresponding author: name: maha jawdat makki, email: engma915@gmail.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. removal of ranitidine using chlorella sorokiniana mh923013 maha jawdat makki a, *, mahmood k. h. al-mashhadani a, and salam k. al-dawery b a chemical engineering department, college of engineering, university of baghdad, baghdad, iraq b department of chemical engineering, college of engineering and architecture, university of nizwa, nizwa, sultanate of oman abstract the frequent and widespread use of medicines and personal care products, particularly in the residential environment, tends to raise concerns about environmental and human health impacts. on the other hand, carbon dioxide accumulation in the atmosphere is a problem with numerous environmental consequences. microalgae are being used to bioremediate toxins and capture co2. the current study aimed to confirm the possibility of removing pharmaceutical contaminant (ranitidine) at different concentrations by using the chlorella sorokiniana mh923013 microalgae strain during the growth time. as part of the experiment, carbon dioxide was added to the culture medium three times per week. explanatory results revealed that gas doses directly affect microalgae growth and removal efficiency, as evidenced by faster and more productive cell adaptation compared to control cultures. the development profile of microalgae is significantly influenced by pure carbon dioxide bubbles. when compared to control flasks, carbon dioxide increased the specific growth rate and doubling time. during the 312 hours microalgae cultivation period, the chlorella strain recorded the highest pollutant removal efficiency (58%), particularly at the pollutant concentration of 5 mg/l co2. keywords: bioremediation, carbon dioxide, chlorella, microalgae, pharmaceuticals, pollutants, ranitidine. received on 12/09/2022, received in revised form on 30/11/2022, accepted on 01/12/2022, published on 30/06/2023 https://doi.org/10.31699/ijcpe.2023.2.4 1introduction the increased production of urban wastewater has been demonstrated to be one of humanity's major environmental concerns. the limited availability of clean water resources across many developing countries may indeed be caused by a failure to conduct appropriately treated wastewater or to empty liquid waste into nearby bodies of water at levels below the environmental level [1]. as a result of industrial, agricultural, and domestic activities, both organic and inorganic contaminants, as well as various pollutants tend to range from micropollutants to heavy metal ions and high nutrient loads, are released into the nearby bodies of water. emerging contaminants include pharmaceuticals and personal care products (ppcps), contrast media, plasticizers, food additives, wood preservatives, laundry detergents, surfactants, disinfectants, flame retardants, and pesticides [2]. these emerging contaminants (ecs) were discovered in low concentrations in conventional wastewater plants. on the other hand, these compounds can take place either naturally or artificially and go undetected in the environment [3]. pharmaceuticals, which are contaminants, have garnered a great deal of attention recently. although much is known about the toxicological and pharmacological effects of these potent, physiological substances at large concentrations, little has been known about their impact on the environment [4]. these pollutants are implemented in liquid facilities for waste treatment after being discharged into sewage systems, where there is a requirement to lower organic pregnancy, nitrogen, phosphorous, and pathogens [5]. although these pollutants are hydrophobic, conventional methods of treatment cannot eliminate them. because emerging pollutants are not removed and degraded, they cause serious problems. even though low-dose exposure over time can cause harm to plants and fish by interfering with propagation and tissue accumulation [6, 7]. chemical methods are widely used to treat wastewater from the pharmaceutical industry. however, significant drawbacks include harsh reaction conditions, high operating costs, and secondary pollutant production. bioremediation is a biological process that transforms xenobiotic pollutants and non-conventional into less dangerous forms (the only end products are water and carbon dioxide) [8]. pharmaceuticals and personal care products (ppcps) are degraded by microorganisms (microalgae, bacteria, or fungi) through a variety of mechanisms, including bioadsorption, bioaccumulation, biodegradation, photolysis, and volatilization. because ppcps have various chemical and physical properties, microalgae select one or a combination of procedures to eliminate them from water [9]. the selection of microalgae for wastewater treatment is determined by their resistance to wastewater and their ability to grow in and absorb nutrients from wastewater [10]. microalgae-based wastewater treatment is less expensive to operate and more environmentally sustainable than conventional http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:engma915@gmail.com http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2023.2.4 m. j. makki et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 31 39 32 wastewater treatment [11]. some of the advantages include the portability of microalgae to climatic changes and also the varying nature of wastewater [12]. microalgae treatment appears to be more productive than conventional wastewater treatment due to the fact it is capable of treating the wastewater in such a single motion that includes various strategies to stabilize nitrogen, carbon, and phosphorous ratios. it can also be an environmentally friendly choice as it can transform carbon dioxide into chemical elements and fuel without causing environmental pollution, thereby lowering the emission of greenhouse gases [13, 14]. plants and microorganisms normally absorb and consume co2 as part of their photosynthetic ability, trying to make this an attractive development opportunity. microalgae and cyanobacteria, on the other hand, develop much faster than terrestrial plants and fix carbon dioxide 10 to 50 times more efficiently [15]. co2 fixation by microalgal species, in conjunction with the production of biofuel and treatment of wastewater, may represent an excellent alternative strategy for co2 mitigation [16, 17]. this study aims to know the activity of (chlorella sorokiniana mh923013) microalgae strain which is pure and isolated from the iraqi soil, as well as registered at the genetic bank database in bioremediation ranitidine through the growth rate and removal efficiency for this pollutant. 2materials and methods 2.1. preparation of stock solution the emerging pollutant used was (ranitidine hcl). ranitidine hydrochloride (𝐶13 𝐻22 𝑁4 𝑂3 𝑆) manufactured in india by sun pharmaceutical industries ltd (purity of 99.46% produced), degradation occurs with increasing temperature, ambient oxygen, and the presence of humidity. the medication (ranitidine hcl) stock solution was prepared from sterile purified water, distilled that used filter paper, and kept in the dark until needed. the stock solution was prepared into four concentrations (5, 15, 25, and 35) mg/l. 2.2. culture media sterilization microalgae sterilization is an essential step in the process. this procedure focuses on eliminating any undesirable germs in order to reduce contamination [18]. this was accomplished through autoclave sterilization of bg-11 media (bioreadytm media – china), the culture media bg-11 used in this study was (15 l) which was prepared by dissolving 1.627 grams of bg-11 in 1000 ml of distilled water. the ph value was adjusted with 1m naoh or hcl if it did not achieve the required value of 7.the autoclave took 15 minutes to reach its maximum temperature of 121 ℃ and pressure of approximately 2 bar. 2.3. microalgae species cultivation the ph of the bg-11 nutrient medium was corrected with (0.1 n) hcl and naoh. a 5 ml stock of the chlorella sorokiniana mh923013 microalgae strain was grown in 500 ml bg-11 medium in a 500 ml conical flask with one repeater, yielding 2 copies of the error bar. all tests were carried out in an incubator with a continuous light intensity of 168 𝜇𝐸𝑚−2𝑠 −1 and an ambient temperature of (24 ±1 ℃ ). 2.4. experimental setup and measurements laboratory experiments included applying a two-part system, the initial part of which consisted mainly of algal cultures placed in an incubator with continuous lighting and a temperature suitable for microalgae growth, and the second of which consisted of a sparing system that included the use of carbon dioxide gas with a flow rate 2 l/min and the presence of containers directly connected to the gas source as shown in fig. 1 and fig. 2. the strain used in this study was chlorella sorokiniana mh923013, which was divided into two groups: concentrations (5, 15, 25, 35) mg/l and a control group with one repeater for each concentration with the presence of a carbon dioxide as a first group, the second group contains the same concentrations and control as the first, but without the addition of the carbon dioxide for the second group. each conical flask for concentrations contains 5 ml of culture media, which was then added to 500 ml of previously prepared and sterilized nutrition medium (bg-11). at the start of the experiments, the (ranitidine hcl) was added in concentrations of (5, 15, 25, 35) mg/l. aeration gas was pumped with a flow rate 2 l/min into the microalgae culture medium for (5 min) and for a volume of (50) ml of microalgal cultures for three times per week, to avoid a drop in ph. the flasks were manually shaken throughout growth to prevent clumping of microalgae cells and to maintain cellular proliferation. microalgal culture samples have their growth kinetics measured using a uv spectrophotometer (genesys 10uv, usa) set to (680) nm [19]. the pollutant concentration was measured at (313) nm [20]. fig. 1. microalgae farms after added 50 ml of carbon dioxide to culture medium concentrations (5, 15, 25, 35) mg/l and a control group with light intensity 168 𝜇𝐸𝑚−2𝑠−1 and an ambient temperature (24 ±1 ℃ ) m. j. makki et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 31 39 33 fig. 2. screenshot of the experimental set-up used in the current study (sparging carbon dioxide gas into 50 ml of microalgae culture medium for 5 min with a flow rate 2 l/min at room temperature) 3growth rate kinetic growth curves related to algal biomass density over time were constructed using specific growth rate estimation. the specific growth was calculated using the straight line formula shown below [21]. 𝑆𝑔 xn = 𝑑𝑥𝑛 𝑑𝑡 (1) 𝑆𝑔 is the specific growth rate (𝑑𝑎𝑦 −1 ), xn is the biomass concentration of the cells (𝑔𝐿−1). by rearranging eq. 1: 𝑆𝑔= 1 𝑥𝑛 𝑑𝑥𝑛 𝑑𝑡 = 𝑑 𝑙𝑛 𝑥𝑛 𝑑𝑡 (2) if 𝑆𝑔 remains constant over time during the exponential growth rate, integrate eq. 2 from (t0 to t) as follows: 𝑆𝑔= ln(𝑥𝑛 𝑥𝑛0 ) ⁄ 𝑡− 𝑡0 (3) xn is the final concentration of microalgal biomass at any time t, 𝑥𝑛0 is the initial cell concentration at the beginning of active logarithmic phase at time 𝑡0. the time required for doubling the cell mass is called as doubling time (𝑡𝑑 ), the doubling time by setting the cell to be doubled (𝑥𝑛 = 2𝑥𝑛0) and (𝑡0 = 0) [22], can be calculated as follows: 𝑡𝑑 = ln 2 𝑆𝑔 (4) in this study, the carbon source for metabolic activities was pure carbon dioxide gas. nutrient availability, culture environment, and cultivation media all have an impact on microalgae growth profiles. chlorella sorokiniana mh923013 had the highest optical density (0.3795) at concentration of pollutant 35 mg/l with co2 after 312 hours of experimental cultivation. 4results and discussions although the microalgae seem to be more sensitive to antibiotics and antimicrobials compared to all other types of ppcps, no significant toxicity was observed in microalgae exposed to ppcps from an antihistamine drug (ranitidine). the presence of that kind of drug molecule had no negative impact on the rate of growth of microalgae. the current research demonstrated this fact by growing one type of microalgae (chlorella sorokiniana mh923013) that can grow in the iraqi climate and was used in laboratory tests, as shown in fig. 1. light intensity, ph, temperature, carbon dioxide, and the nutritional content of the growing medium all have an impact on microalgae production systems, and some of them seem to be the most various environmental factors influencing algal advancement and biomass production. all of the above variables were carefully controlled in the current research to study the impact of ranitidine on the growth of the microalgae used. the stable growth of all traditional cultures (control) showed a positive indication that such a type of pollutant could be dealt with in microalgae cultures in the future. sparging carbon dioxide into 50 ml of culture media has been observed to have a significant influence on the microalgae development profile, as it increases the number of microalgal cells. this improvement in microalgae strain was noticed after adding 2 l/min of co2 gas for five minute to 50 ml culture medium at various concentrations. several experiments were performed during this time period to determine the volumetric flow rate of pure co2 in order to achieve complete co2 saturation while attempting to avoid a decrease in the ph of a main medium, if this occurs, may cause the death of microalgae cells. the experimental results show that chlorella sorokiniana after 192 hours recorded optical density (0.148) for the concentration of pollutant (25 mg/l) with carbon dioxide, and (0.1205, 0.13) for pollutant concentrations with carbon dioxide (5 and 15) mg/l. chlorella recorded optical density (0.102) in the existence of a carbon source at a pollutant concentration of 35 mg/l after 144 hours, indicating pollution consumption. the control group for chlorella strain recorded optical density (0.342) with and without carbon source (0.1255) after 312 hours, sees fig. 3. fig. 3. growth rate of chlorella sorokiniana mh923013 microalgae with and without carbon dioxide (aeration gas 2 l/min, light intensity 168 𝜇𝐸𝑚−2𝑠−1 and temperature (24 ±1 ℃ )) m. j. makki et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 31 39 34 table 1 displays the specific growth rate of a microalgae strain used in this research (chlorella sorokiniana mh923013) in addition to the strain's doubling time at various ranitidine concentrations (0, 5, 15, 25, 35 mg/l). the results indicate that the concentration levels of the pollutant material in the culture media influence the responses of the doubling time and specific growth rate. when other process parameters (including the source of carbon dioxide) have been controlled, the specific growth rate and generation time (doubling time) of chlorella sorokiniana mh923013 significantly improved. the specific growth rates of this strain (0.0104, 0.0093, 0.0085, and 0.0096 hr −1) and the doubling time (67, 75, 81, and 72) hr at various pollutant concentrations (5, 15, 25, 35) mg/l have indeed been registered, respectively. these results are slightly better than any of those gained in control bioreactors which registered a specific rate of growth (0.0082hr−1 ) and doubling time (84 hr). these findings indicate that the presence of such a type of pollutant in the culture medium has a positive effect on the growth rate kinetics. this impact, however, may be affected by the kind of microalgae used in cultivation. for all ranitidine concentrations, the specific growth rate and doubling time improved. carbon metabolism enzymes such as ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) and carbonic anhydrase are affected by co2 abundance [23]. table 1. the specific growth rate and doubling time during 312 hours time (hr) microalgae strain concentrations mg/l specific growth rate (𝝁𝒓 ) doubling time ( 𝐭𝐝 ) 𝐂𝐎𝟐 without 𝐂𝐎𝟐 𝐂𝐎𝟐 without 𝐂𝐎𝟐 312 chlorella sorokiniana mh923013 5 15 25 35 control 0.0144 0.014 0.0143 0.0142 0.0114 0.0104 0.0093 0.0085 0.0096 0.0082 48 50 49 49 61 67 75 81 72 84 the volume of microalgae inoculation (chlorella sorokiniana mh923013) used in this investigation was (5 ml). this amount of inoculums has been approved by research regardless of the strain used [24]. add 50 ml of culture medium with co2 as a dose resulted in a significant increase (2.02) in (x-factor) for 312 hours when compared to prior study [25] that resulted in (4.5) for chlorella sorokiniana mh923013. the rate of growth was demonstrated in the current research (1.68, 1.76, 1.69, and 2.02) with concentrations (5, 15, 25, 35) mg/l of pollutant (drug) see table 2. table 2. the effect of carbon dioxide addition on the growth rate in the current study after 312 hours dic dosing microalgae strain concentrations mg/l x factor based control 50 ml chlorella sorokiniana mh923013 5 15 25 35 1.68 1.76 1.69 2.02 when pure carbon dioxide is used in cultivation systems, the ph rapidly drops, causing adverse environmental conditions for the majority of microorganisms, including microalgae. the inlet co2 concentration must not only be less than the critical value so that it will not satisfy the carbon requirements of microalgae. however, it should never exceed the maximum limit in order to prevent a large loss of co2 which cannot be utilized by the microalgae species and is released to the environment by the microalgae culture, as a result of which unnecessary environmental contamination occurs. as the concentration of pure co2 in the solution increases, the ph of the microalgae solution decreases. nevertheless, as co2 levels start rising, photosynthetic capacity and microalgae growth keep increasing, causing ph to increase. other several authors have already had comparable success. according to [26] and [27], photosynthesis for carbon dioxide fixation tends to make a reasonable ph increase because of the accumulation of ohwhereas co2 dissolution in water causes acidification resulting in the formation of carbonic acid. it has been observed that higher ph levels prevent cell growth through accumulating carbonates which microalgae cannot absorb. high concentrations also inhibited photosynthetic activity of microalgae through intracellular carbon anhydrase, resulting in a decrease of carbon dioxide residues in flue gases [28]. carbon dioxide availability and solubility in the photobioreactor are directly proportionate to the ph of the microalgae culture medium [29]. the determining factor in the process of photosynthesis of microalgae is bicarbonate, and also the carbon compound proportions change as the ph changes (carbonate, carbon dioxide and bicarbonate) [28]. regarding mass transfer, it ought to be that the presence of other gases can restrict the rate at which carbon dioxide transfer to the cultivation medium [30]. prior studies used a gas mixed with co2 to regulate the amount of co2 dissolved inside in medium. ying et al [31] used a mixture (95% nitrogen and 5 % carbon dioxide) as in cultivation of microalgae to regulate the quantity of carbon dioxide dissolved as well as keep the ph stable. in the current study, the method of pumping gas used was pure carbon dioxide gas, which differed from previous studies. the gas was bubbled with (2 l/min) and for (5 min) into volume of fifty ml of microalgal cultures for three times per week, to avoid a drop in ph in main flask. instead of all of the microalgae cultures, the spray system was used to direct the gas to a specific amount of culture medium. this method was effective and suitable because it attributed to an increase in production of m. j. makki et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 31 39 35 biomass while having no adverse influence on the ph value, as shown in fig. 4. fig. 4. ph values after (50 ml) of carbonic culture medium was added to chlorella sorokiniana mh923013 culture flasks 5pollutant removal ranitidine is an environmentally significant medication because of its incomplete metabolism [32] since of poor discharge in wastewater treatment, microalgae will not be capable of completely eliminate it [33]. as shown in table 3, the current research supports prior studies. the chlorella strain achieved the highest pollutant removal efficiency (58%) during the microalgae cultivation period of 312 hours, especially that produced at pollutant concentration 5 mg/l with co2, as shown in table 3. other carbon dioxide concentrations reported (30, 22.2, 10) % at (15, 25, 35) mg/l of ranitidine. the maximum removal efficiency was observed at 5 mg/l including both cases with and without co2 , indicating that lower concentrations consume faster than higher concentrations. the lowest percentage removal for chlorella was 10% with carbon dioxide and 14% without carbon dioxide at a concentration of pollutant 35 mg/l. the increase in biological degradation could imply that enzymatic hydrolysis of microalgae is a viable drug resistance mechanism, several enzymatic pathways, including hydroxylation, methylation, nitrosation, and deamination, have been used to biodegrade the medication [34]. the ph and type of the extracellular polymeric particle sizes in the bioreactor may influence the capability of microalgae to absorb micropollutants [35]. table 3. efficiency of removal after 312 hours of cultivation microalgae concentrations mg/l %removal efficiency with 𝐂𝐎𝟐 %removal efficiency without co2 chlorella sorokiniana mh923013 5 15 25 35 58 30 22.2 10 53 30 21 14 because carbon and nitrogen are embedded in the suspended particles, microalgae find it difficult to use them. in co-cultivation, fungal extra cellular enzymes can transform molecular organic compounds into soluble nutrients, in which enzyme-treated components could be absorbed [36]. as a result of self-reinforcing interactions between microalgae and fungi. in terms of nutrient removal (e.g. phosphorus, nitrogen), a co-cultivation process may be more effective than a monoculture system [8]. in comparison to a mono microalgae culture system, the combined culture of microalgae and fungi could absorb as well as digest more ranitidine [37]. fungi produce extracellular enzymes that degrade solid organic waste in to the soluble nutrients and co2, because microalgae cannot break down organic wastes, they find it difficult to metabolize and eliminate them from the environment [38]. the recent experimental results demonstrated that at a concentration of 5 mg/l, the removal percentages of the pharmacological pollutant in the monoculture system of microalgae ranged from 58% in the presence of a carbon source to 53% in the absence of a carbon source. this percentage may well be low when compared to the removal of ibuprofen and paracetamol by microalgae, as indicated in [39]. in this research, it was discovered that chlorella sorokiniana mh923013 microalgae consume some pharmaceutical contaminants more efficiently than some other types of microalgal species. because ranitidine was difficult to eliminate using a monoculture of microalgae, researchers needed to combine fungi and microalgae to create biopellets [40]. they combine fungi as well as micoalgae to produce biopellets, and they were capable of removing ranitidine with such percentage of (50 ±19) % by biopellets and (30±12) % by fungus, but in this study, chlorella was used and the highest removal percentage was (58%) during 312 hours. the carbon dioxide gas was employed to enhance the rate of removal of pollutants by microalgae. when a carbon source such as co2 gas, was added, the removal rate increased by a factor of just one, as it appears to have done in some concentrations. 6conclusion 1. in a suitable environment, chlorella sorokiniana mh923013 microalgae was successfully grown. 2. despite the availability of the contaminant at various concentrations, this study revealed that carbon dioxide has a direct impact on the growth of microalgae species, predicated on measured growth at doses of (50) ml, particularly in comparison to control groups of variable certified strains, which clearly showed slow and irregular growth. 3. at all concentrations tested (5, 15, 25, and 35) mg/l, the availability of a pharmaceutical pollutant ranitidine appeared to have an impact on the specific rate of growth and doubling time at all concentrations tested (5, 15, 25, 35) mg/l; additionally, the growth process occurred on a regular basis in a carbon-rich environment. 4. the highest removal efficiency value was recorded for chlorella sorokinana mh923013 microalgae strain, m. j. makki et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 31 39 36 which was 58% in the presence of carbon dioxide and 53% without carbon dioxide at contaminant concentration of 5 mg/l. references [1] s. n., onuoha, f. i. idike, and l.c., orakwe. ‘‘water supply resources for domestic purposes in auchi metropolis of edo state, nigeria’’. international journal of engineering and technology, vol.2, no.6. june. 2012. [2] m.la farre, s.pérez, l. kantiani, and d.barceló .‘‘fate and toxicity of emerging pollutants, their metabolites and transformation products in the aquatic environment’’. trac trends in analytical chemistry, vol.27, no. 11, pp.991-1007. dec. 2008. https://doi.org/10.1016/j.trac.2008.09.010 [3] j.r.petrie, n. chaturvedi, i. ford, m.c. brouwers, n. greenlaw, t. tillin, i. hramiak, a.d.hughes, a.j. jenkins, b.e klein, and r. klein, ‘‘cardiovascular and metabolic effects of metformin in patients with type 1 diabetes (removal): a double-blind, randomised, placebo-controlled trial’’. the lancet diabetes & endocrinology, vol.5, no.8, pp.597-609, aug. 2017. https://doi.org/10.1016/s2213-8587(17)30194-8 [4] a. b. boxall, m. a.rudd, b. w.brooks, d.j. caldwell, k.choi, s. hickmann, e. innes, k. ostapyk, j.p. staveley, t. verslycke, and g.t. ankley, ‘‘pharmaceuticals and personal care products in the environment: what are the big questions?.’’. environmental health perspectives, vol.120, no. 9, pp.1221-1229, sep. 2012. https://doi.org/10.1289/ehp.1104477 [5] j. kang, x. duan, c. wang, h. sun, x. tan, m.o. tade, and s. wang, ‘‘nitrogen-doped bamboo-like carbon nanotubes with ni encapsulation for persulfate activation to remove emerging contaminants with excellent catalytic stability’’. chemical engineering journal, vol.332, pp.398-408, jan. 2018. https://doi.org/10.1016/j.cej.2017.09.102 [6] j. wang, and s. wang. ‘‘removal of pharmaceuticals and personal care products (ppcps) from wastewater: a review’’. journal of environmental management, vol. 182, pp.620-640, nov. 2016. https://doi.org/10.1016/j.jenvman.2016.07.049 [7] z. gojkovic, r. h. lindberg, m. tysklind, and c. funk, ‘‘northern green algae have the capacity to remove active pharmaceutical ingredients’’. ecotoxicology and environmental safety, vol. 170, pp.644-656, april. 2019. https://doi.org/10.1016/j.ecoenv.2018.12.032 [8] a. silva, c. delerue-matos, s. a. figueiredo, and o.m. freitas, ‘‘the use of algae and fungi for removal of pharmaceuticals by bioremediation and biosorption processes: a review’’. water, vol.11, no. 8, p.1555, jul. 2019. https://doi.org/10.3390/w11081555 [9] s. hena, l. gutierrez, and j. p. croué, ‘‘removal of pharmaceutical and personal care products (ppcps) from wastewater using microalgae: a review’’. journal of hazardous materials,vol.403, p.124041, feb. 2021. https://doi.org/10.1016/j.jhazmat.2020.124041 [10] o. sahu. ‘‘reduction of organic and inorganic pollutant from waste water by algae’’. international letters of natural sciences, vol. 8, no.1, 2014. https://doi.org/10.56431/p-8aq47u [11] j. j. j. y. yong, k. w. chew, k. s. khoo, p. l. show, and j.s. chang, ‘‘prospects and development of algal-bacterial biotechnology in environmental management and protection’’. biotechnology advances, vol.47, p.107684. mar. 2021. https://doi.org/10.1016/j.biotechadv.2020.107684 [12] i. ahmad, n. abdullah, i. koji, a. yuzir, and s.e. mohamad. ‘‘potential of microalgae in bioremediation of wastewater’’. bulletin of chemical reaction engineering & catalysis, vol.16, no.2, pp.413-429. jun. 2021. https://doi.org/10.9767/bcrec.16.2.10616.413-429 [13] p. l. show, m. s. tang, d. nagarajan, t.c. ling, c. w. ooi, and j. s. chang, ‘‘a holistic approach to managing microalgae for biofuel applications’’. international journal of molecular sciences, vol.18, no. 1, p.215, jan.2017. https://doi.org/10.3390/ijms18010215 [14] a. k. koyande, k. w. chew, k. rambabu, y. tao, d.t. chu, and p. l. show. ‘microalgae: a potential alternative to health supplementation for humans’’. food science and human wellness, vol .8, no.1, pp.16-24. mar. 2019. https://doi.org/10.1016/j.fshw.2019.03.001 [15] n. m. langley, s. t. l. harrison, and r. p. van hille, ‘‘a critical evaluation of co2 supplementation to algal systems by direct injection’’. biochemical engineering journal, vol.68, pp.70-75, 2012. https://doi.org/10.1016/j.bej.2012.07.013 [16] b. wang, y. li, n. wu, and c.q. lan, ‘‘co2 biomitigation using microalgae’’. applied microbiology and biotechnology, vol.79, no.5, pp.707-718. jul. 2008. https://doi.org/10.1007/s00253-008-1518-y [17] k. t lamlee, and, a.r. mohamed ‘‘current status and challenges on microalgae-based carbon capture’’. international journal of greenhouse gas control, vol.10, pp.456-469, sep. 2012. https://doi.org/10.1016/j.ijggc.2012.07.010 [18] v. kothari, m. patadia, and n. trivedi, ،،microwave sterilized media supports better microbial growth than autoclaved media’’. research in biotechnology, vol.2, no.5. oct. 2011. [19] l. h. santos, a. n. araújo, a. fachini, a. pena, delerue-matos, and m. c. b. s. m. montenegro, ‘‘ecotoxicological aspects related to the presence of pharmaceuticals in the aquatic environment’’. journal of hazardous materials, vol. 175, (1-3), pp.45-95. oct. 2010. https://doi.org/10.1016/j.jhazmat.2009.10.100 https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=0d187488aa7433ed0a461a24b07b373782a6ce7f https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=0d187488aa7433ed0a461a24b07b373782a6ce7f https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=0d187488aa7433ed0a461a24b07b373782a6ce7f https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=0d187488aa7433ed0a461a24b07b373782a6ce7f https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=0d187488aa7433ed0a461a24b07b373782a6ce7f https://doi.org/10.1016/j.trac.2008.09.010 https://doi.org/10.1016/s2213-8587(17)30194-8 https://doi.org/10.1289/ehp.1104477 https://doi.org/10.1016/j.cej.2017.09.102 https://doi.org/10.1016/j.jenvman.2016.07.049 https://doi.org/10.1016/j.ecoenv.2018.12.032 https://doi.org/10.3390/w11081555 https://doi.org/10.1016/j.jhazmat.2020.124041 https://doi.org/10.56431/p-8aq47u https://doi.org/10.1016/j.biotechadv.2020.107684 https://doi.org/10.9767/bcrec.16.2.10616.413-429 https://doi.org/10.3390/ijms18010215 https://doi.org/10.1016/j.fshw.2019.03.001 https://doi.org/10.1016/j.bej.2012.07.013 https://doi.org/10.1007/s00253-008-1518-y https://doi.org/10.1016/j.ijggc.2012.07.010 https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=1ba18774f00b87ceb3421a4f2ac945c70735ed2a https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=1ba18774f00b87ceb3421a4f2ac945c70735ed2a https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=1ba18774f00b87ceb3421a4f2ac945c70735ed2a https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=1ba18774f00b87ceb3421a4f2ac945c70735ed2a https://doi.org/10.1016/j.jhazmat.2009.10.100 m. j. makki et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 31 39 37 [20] a. n. mishra, and a. rana, ‘‘uv spectrophotometric determination of ranitidine hydrochloride in pure and pharmaceutical formulation’’. int. j. chem. sci, vol.7, no. 3, pp.2208-2210. 2009. [21] s. bhatia, k. sharma, r. dahiya, and b. tanmoy, ‘‘modern applications of plant biotechnology in pharmaceutical sciences’’ academic press. jul. 2015. [22] j. h. van heerden, h. kempe, a. doerr, t. maarleveld, n. nordholt, and f. j. ‘‘bruggeman, statistics and simulation of growth of single bacterial cells: illustrations with b. subtilis and e. coli’’. scientific reports, vol.7, no. 1, pp.1-11, nov. 2017. https://doi.org/10.1038/s41598-017-15895-4 [23] a. m. lakaniemi, c. j. hulatt, d. n. thomas, and j. a. puhakka. ‘‘carbon dioxide utilization in gassparge microalgal photobioreactors,’’ in conference paper presented at: asian biohydrogen, bioproducts symposium. chongqing, china, 2015. [24] f., kokou, p. makridis, m. kentouri, and p. divanach, ‘‘antibacterial activity in microalgae cultures’’, aquaculture research, vol, 43 no. 10, pp.1520-1527, sep. 2012. https://doi.org/10.1111/j.1365-2109.2011.02955.x [25] r. s. mahdi, m. k. al-mashhadani, and i. j. abed, ‘‘pre-dissolved inorganic carbon (dic) for cultivation chlorella sorokiniana mh923013, coelastrella mh923011 and coelastrella mh923012,’’. in iop conference series: materials science and engineering (vol. 1076, no. 1, p. 012025), feb. 2021. https://doi.org/10.1088/1757899x/1076/1/012025 [26] j. u. grobbelaar, ‘‘algal nutrition: mineral nutrition,’’ handbook of microalgal culture: biotechnology and applied phycology, pp.97-115. 2004. https://doi.org/10.1002/9780470995280.ch6 [27] m. g. de morais, and j. a. v costa, ،،biofixation of carbon dioxide by spirulina sp. and scenedesmus obliquus cultivated in a three-stage serial tubular photobioreactor,’’ journal of biotechnology, vol.129,no. 3, pp.439-445, may. 2007. https://doi.org/10.1016/j.jbiotec.2007.01.009 [28] l. cheng, l.z hang, h. chen, and c. gao, ‘‘carbon dioxide removal from air by microalgae cultured in a membrane-photobioreactor,’’ separation and purification technology, vol. 50, no. 3, pp.324-329. jul .2006. https://doi.org/10.1016/j.seppur.2005.12.006 [29] s. f. mohsenpour, and n. willoughby, ‘‘effect of co2 aeration on cultivation of microalgae in luminescent photobioreactors,’’ biomass and bioenergy, vol. 85, pp.168-177, feb. 2016. https://doi.org/10.1016/j.biombioe.2015.12.002 [30] h. t. hsueh, h. chu, and s.t yu, ‘‘a batch study on the bio-fixation of carbon dioxide in the absorbed solution from a chemical wet scrubber by hot spring and marine algae,’’ chemosphere, vol.66, no. 5, pp.878-886. jan. 2007. https://doi.org/10.1016/j.chemosphere.2006.06.022 [31] k. ying, m. k. al-mashhadani, j. o. hanotu, d.j. gilmour, and w. b. zimmerman, ‘‘enhanced mass transfer in microbubble driven airlift bioreactor for microalgal culture,’’ engineering, vol.5, no. 9, pp.735-743. 2013a. https://doi.org/10.4236/eng.2013.59088 [32] k. vediappan, and c.w. lee, ‘‘electrochemical approaches for the determination of ranitidine drug reaction mechanism,’’ current applied physics, vol.11, no.4, pp.995-1000. jul. 2011. https://doi.org/10.1016/j.cap.2011.01.007 [33] m. gros, s. rodríguez-mozaz, and d. barceló, ‘‘fast and comprehensive multi-residue analysis of a broad range of human and veterinary pharmaceuticals and some of their metabolites in surface and treated waters by ultra-high-performance liquid chromatography coupled to quadrupole-linear ion trap tandem mass spectrometry,’’ journal of chromatography a, vol. 1248, pp.104-121. jul. 2012. https://doi.org/10.1016/j.chroma.2012.05.084 [34] j. q. xiong, s. govindwar, m. b. kurade, k. j. paeng, h. s. roh, m. a. khan, and b. h. jeon, ‘‘toxicity of sulfamethazine and sulfamethoxazole and their removal by a green microalga, scenedesmus obliquus,’’ chemosphere, vol.218, pp.551-558. mar. 2019. https://doi.org/10.1016/j.chemosphere.2018.11.146 [35] d. l. cheng, h. h. ngo, w. s. guo, s. w. chang, d.d. nguyen, and w. s. s. m. kumar, ‘‘microalgae biomass from swine wastewater and its conversion to bioenergy,’’ bioresource technology, vol.275, pp.109-122. 2019. https://doi.org/10.1016/j.biortech.2018.12.019 [36] j. hu, d. nagarajan, q. zhang, j. s. chang, and d. j. lee, ‘‘heterotrophic cultivation of microalgae for pigment production: a review,’’ biotechnology advances, vol.36, no. 1, pp.54-67. 2018. https://doi.org/10.1016/j.biotechadv.2017.09.009 [37] r. chu, s. li, l. zhu, z. yin, d. hu, c. liu, and f. mo, ‘‘a review on co-cultivation of microalgae with filamentous fungi: efficient harvesting, wastewater treatment and biofuel production,’’ renewable and sustainable energy reviews, vol.139, p.110689. 2021. https://doi.org/10.1016/j.rser.2020.110689 [38] l. yang, h. li, and q. wang, ‘‘a novel one-step method for oil-rich biomass production and harvesting by co-cultivating microalgae with filamentous fungi in molasses wastewater,’’ bioresource technology, vol. 275, pp.35-43. 2019. https://doi.org/10.1016/j.biortech.2018.12.036 [39] a. de wilt, a. butkovskyi, k. tuantet, l. h. leal, t. v. fernandes, a. langenhoff, and g. zeeman, ‘‘micropollutant removal in an algal treatment system fed with source separated wastewater streams,’’ journal of hazardous materials, vol.304, pp.84-92. 2016. https://doi.org/10.1016/j.jhazmat.2015.10.033 https://www.tsijournals.com/articles/uv-spectrophotometric-determination-of-ranitidine-hydrochloride-in-pure-and-pharmaceutical-formulation.pdf https://www.tsijournals.com/articles/uv-spectrophotometric-determination-of-ranitidine-hydrochloride-in-pure-and-pharmaceutical-formulation.pdf https://www.tsijournals.com/articles/uv-spectrophotometric-determination-of-ranitidine-hydrochloride-in-pure-and-pharmaceutical-formulation.pdf https://www.tsijournals.com/articles/uv-spectrophotometric-determination-of-ranitidine-hydrochloride-in-pure-and-pharmaceutical-formulation.pdf https://books.google.iq/books?hl=en&lr=&id=kvacbaaaqbaj&oi=fnd&pg=pp1&dq=modern+applications+of+plant+biotechnology+in+pharmaceutical+sciences&ots=tj4n0nhhfq&sig=gxlot0p1zcb0l8axloc2fsbpb2e&redir_esc=y#v=onepage&q=modern%20applications%20of%20plant%20biotechnology%20in%20pharmaceutical%20sciences&f=false https://books.google.iq/books?hl=en&lr=&id=kvacbaaaqbaj&oi=fnd&pg=pp1&dq=modern+applications+of+plant+biotechnology+in+pharmaceutical+sciences&ots=tj4n0nhhfq&sig=gxlot0p1zcb0l8axloc2fsbpb2e&redir_esc=y#v=onepage&q=modern%20applications%20of%20plant%20biotechnology%20in%20pharmaceutical%20sciences&f=false https://books.google.iq/books?hl=en&lr=&id=kvacbaaaqbaj&oi=fnd&pg=pp1&dq=modern+applications+of+plant+biotechnology+in+pharmaceutical+sciences&ots=tj4n0nhhfq&sig=gxlot0p1zcb0l8axloc2fsbpb2e&redir_esc=y#v=onepage&q=modern%20applications%20of%20plant%20biotechnology%20in%20pharmaceutical%20sciences&f=false https://doi.org/10.1038/s41598-017-15895-4 https://www.researchgate.net/profile/david-thomas-3/publication/257815310_carbon_utilization_in_gas-sparged_microalgal_photobioreactors/links/0deec525e2c578bf7e000000/carbon-utilization-in-gas-sparged-microalgal-photobioreactors.pdf https://www.researchgate.net/profile/david-thomas-3/publication/257815310_carbon_utilization_in_gas-sparged_microalgal_photobioreactors/links/0deec525e2c578bf7e000000/carbon-utilization-in-gas-sparged-microalgal-photobioreactors.pdf https://www.researchgate.net/profile/david-thomas-3/publication/257815310_carbon_utilization_in_gas-sparged_microalgal_photobioreactors/links/0deec525e2c578bf7e000000/carbon-utilization-in-gas-sparged-microalgal-photobioreactors.pdf https://www.researchgate.net/profile/david-thomas-3/publication/257815310_carbon_utilization_in_gas-sparged_microalgal_photobioreactors/links/0deec525e2c578bf7e000000/carbon-utilization-in-gas-sparged-microalgal-photobioreactors.pdf https://www.researchgate.net/profile/david-thomas-3/publication/257815310_carbon_utilization_in_gas-sparged_microalgal_photobioreactors/links/0deec525e2c578bf7e000000/carbon-utilization-in-gas-sparged-microalgal-photobioreactors.pdf https://doi.org/10.1111/j.1365-2109.2011.02955.x https://doi.org/10.1088/1757-899x/1076/1/012025 https://doi.org/10.1088/1757-899x/1076/1/012025 https://doi.org/10.1002/9780470995280.ch6 https://doi.org/10.1016/j.jbiotec.2007.01.009 https://doi.org/10.1016/j.seppur.2005.12.006 https://doi.org/10.1016/j.biombioe.2015.12.002 https://doi.org/10.1016/j.chemosphere.2006.06.022 https://doi.org/10.4236/eng.2013.59088 https://doi.org/10.1016/j.cap.2011.01.007 https://doi.org/10.1016/j.chroma.2012.05.084 https://doi.org/10.1016/j.chemosphere.2018.11.146 https://doi.org/10.1016/j.biortech.2018.12.019 https://doi.org/10.1016/j.biotechadv.2017.09.009 https://doi.org/10.1016/j.rser.2020.110689 https://doi.org/10.1016/j.biortech.2018.12.036 https://doi.org/10.1016/j.jhazmat.2015.10.033 m. j. makki et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 31 39 38 [40] h. bodin, a. daneshvar, m. gros, and m. hultberg, ‘‘effects of biopellets composed of microalgae and fungi on pharmaceuticals present at environmentally relevant levels in water,’’ ecological engineering, vol.91, pp.169-172. 2016. https://doi.org/10.1016/j.ecoleng.2016.02.007 https://doi.org/10.1016/j.ecoleng.2016.02.007 m. j. makki et al. / iraqi journal of chemical and petroleum engineering 24,2 (2023) 31 39 39 chlorella sorokiniana mh923013 باستخدام الرانيتيدين إزالة 2 الداوري كاظم سالم، و 1 حمادي خزعل محمود، ،*1 مكي جودت مها ، العراقبغداد جامعة ،الهندسة كلية ،الكيمياوية الهندسة قسم 1 عمانسلطنة نزوى، نزوى، جامعة والعمارة، الهندسة كلية الكيميائية، الهندسة قسم 2 الخالصة لسكنية،ا البيئة في سيما ال ، الشخصية العناية ومنتجات لألدوية النطاق والواسع المتكرر االستخدام يشير الجوي الفالغ في الكاربون اوكسيد ثنائي تراكم يعد. اإلنسان وصحة البيئة على تأثيرها بشأن المخاوف إثارة إلى اوكسيد ائيثن والتقاط للسموم الحيوية المعالجة في الدقيقة الطحالب استخدام يتم. عديدة بيئية عواقب لها مشكلة مختلفة بتراكيز( رانيتيدين) الصيدالنية الملوثات إزالة إمكانية تأكيد إلى الحالية الدراسة هدفت. الكاربون (. chlorella sorokiniana mh923013) نموها فترة خالل الدقيقة الطحالب من ساللة باستخدام . قيقةالد الطحالب مزارع إلى األسبوع في مرات ثالث الكاربون اوكسيد ثنائي إضافة تمت التجربة، من كجزء لكذ ويتضح اإلزالة، وكفاءة الدقيق، النمو على مباشر تأثير لها الغاز جرعات أن التوضيحية النتائج كشفت بشكل ةالدقيق للطحالب النمو معدل يتأثر. التحكم بمجموعات مقارنة إنتاجية واألكثر األسرع الخاليا تكيف من معدل من ون الكارب اوكسيد ثنائي زاد التحكم، بقوارير المقارنة عند. النقي الكاربون اوكسيد ثنائي بفقاعات كبير فترة خالل٪( 58) الملوثات إزالة في كفاءة أعلى الكلوريال ساللة حققت. الخاليا مضاعفة ووقت المحدد النمو ازغ بوجود لتر/ ملغم 5 الملوث تركيز عند الناتجة تلك خاصة ، ساعة 312 البالغة الدقيقة الطحالب زراعة .الكاربون اوكسيد ثنائي الملوثات، ،الصيدالنية المستحضرات الدقيقة، الطحالب الكلوريال، الكاربون، أوكسيد ثنائي الحيوية، المعالجة الكلمات الدالة: .رانيتيدين available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol.22 no.1 (march 2021) 1 – 13 eissn: 2618-0707, pissn: 1997-4884 corresponding authors: name: amel habeeb assi, email: zahraa_z91@yahoo.com, name: faleh h. m. almahdawi, email:dr.f.h.m.almahdawi@coeng.uobaghdad.edu.iq ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. an experimental assessment of iraqi local cement and cement slurry design for iraqi oil wells using cemcade amel habeeb assi and faleh h. m. almahdawi petroleum engineering department, college of engineering, university of baghdad, baghdad, iraq abstract this effort is related to describe and assess the performance of the iraqi cement sample planned for oil well-cementing jobs in iraq. in this paper, major cementing properties which are thickening time, compressive strength, and free water in addition to the rheological properties and filtration of cement slurry underneath definite circumstances are experimentally tested. the consequences point to that the iraqi cement after special additives encounter the requests of the api standards and can consequently is used in cementing jobs for oil wells. at this research, there is a comparative investigation established on experimental work on the effectiveness of some additives that considered as waste materials which are silica fume, bauxite, and glass powder, and other conventional additives which are: (scr -100 retarder, hr-5, fwca, hollow glass spheres (hgs) and halad-9) that currently used in our fields on local iraqi cement and putting foreign cement results as a governor. chemical analysis for iraqi cement, imported cement, and waste materials samples was determined using the x-ray fluorescence (xrf) technique and found minor differences in composition between those samples and depending on the results of x-ray, we selecting the appropriate additives to prepare cement slurry samples. the x-ray fluorescence (xrf) results show that iraqi cement has a low value of silica which is about 18.63% while omani cement about 37.58%. this research examined the potential of micro silica, bauxite, and waste glass powder to produce sustainable cement slurry. the results showed that adding micro silica and bauxite enhances the performance of iraqi cement but also leads to a slight decrease in thickening time. to avoid this problem, superplasticizer is used to make the process of cement pumping more easily, in other words, increase thickening time and increase compressive strength. furthermore, adding glass powder increase the value of compressive strength. both additives (waste and conventional) are used for the slurry design for achieving better slurry properties, but waste additives increase and enhance iraqi cement performance than conventional additives, in other words, making it more effective than commercial cement. depending on the results of the compressive strength test, the optimal concentration of the waste materials used in this research was found, and then the optimal concentration was used to prepare cement samples. the results showed that the use of waste materials to prepare cement slurry is a promising way to improve the efficiency of cement work and to reduce the negative environmental impact resulting from the industry. the results of the program cemcade proved to be the sample a and c showed good performance through high cement bonding and ideal distribution of fluids designed to accomplish the cementing process. keywords: iraqi cement, additives, slurry design, cementing properties, commercial cement. received on 16/08/2020, accepted on 11/10/2020, published on 30/03/2021 https://doi.org/10.31699/ijcpe.2021.1.1 1introduction portland cement is the most widely used cement in the manufacture of oil wells and is involved in about 99% of the primary cementing. and well-cementing operations using the unusual cement called '' g class cement '', its properties must match the specifications of the american petroleum institute (api)). iraq, which gets high marks among the oil-producing countries, recently started manufacturing oil well cement. cementing operations are an essential part of the oil drilling industry. his success is a critical issue in the continuation of the subsequent stage. installation in oil wells entails inserting cement mortar suitable for good and durable cement bonding. portland cement is a fine powder obtained by mixing a mixture of 80% limestone and 20% clay which are roasted to 1450 ° c. certainly 99% of oil well-cementing operations worldwide are approved with this material [1]. the physical, chemical, and mechanical properties of portland cement must match the specifications of the american petroleum institute (api) to be considered petroleum cement and thus can be used in oil well operations. the task of cementing in oil wells involves introducing cement slurry into the annular space between the liner and the rock formations. petroleum cement is distinctive cement used in the process of cementing oil and gas wells. protect casing from aggressive features that may be a source of corrosion. for the period of oil well cementation, fluid migration overdue the cased holes is the main problem in drilling together short and long terms subsequently cementing operations. extraordinary formation pressures, high shrinkage degree of cement slurry, lack of mechanical seal and channeling due to meager cement slurry design, and those entire is the principal reason for expensive drilling and completion processes and from time to time well abandonment. http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:zahraa_z91@yahoo.com http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2021.1.1 a. h. assi and f. h. m. almahdawi / iraqi journal of chemical and petroleum engineering 22,1 (2021) 1 13 2 different additives are used [2] and numerous categories of cement slurry chemical admixtures for instance; superplasticizers, retarders, accelerators, and viscosity modifiers which are used for optimizing the flow properties of cement slurry [3]. portland cement experiences major chemical and microstructural transformations under high-temperature conditions (>110◦c). such a phenomenon is known as strength retrogression, which increases as long as the temperature increases beyond 110 ◦c [4 and 5]. during the strength retrogression transformation, calcium-rich products are formed in the cement matrix, which will increase the matrix porosity and permeability and deteriorate its mechanical properties. the accurate selection of chemical admixtures is essentially established on a trial and error technique established on marsh cone flow, and the rheological tests [6]. there is a lot of research going on to utilize and recycle bauxite residue [7] including potential applications in the construction industry [8]. however, many processes seem not economically feasible yet to reuse the large amounts of available disposed of br. the cement industry might be the only industry with sufficiently high volumes produced globally to tackle the high amount of bauxite residue produced every year and it is, therefore, necessary to also investigate the feasibility of br to be used as supplementary cementitious material (scm the performance of the chemical additives is intensely influenced by the physical and chemical properties of the cement [9 and 10]. there are several types of cement slurry chemical admixtures such as; superplasticizers, retarders, accelerators, and viscosity modifiers that are used to optimize the flow properties of cement-based products. silica fume or micro silica initially vied as cement replacement material and in some areas, it is usually used as replaced by a much smaller quantity of silica fume micro silica may be used as pozzolanic admixtures [11]. superplasticizer is a type of water reducer; however, the difference between superplasticizer and water reducer is that superplasticizer will significantly reduce the water required for concrete mixing [12 and 13]. generally, there are four main categories of superplasticizer: sulfonated melamineformaldehyde condensates, sulfonated naphthaleneformaldehyde condenses, modified lignosulfonates, and others such as sulfonicacid esters and carbohydrate esters. effects of superplasticizer are obvious, i.e. to produce concrete with very high workability or concrete with very high strength. the mechanism of the superplasticizer is through giving the cement particles a highly negative charge so that they repel each other due to the same electrostatic charge. by deflocculating the cement particles, more water is provided for concrete mixing [14]. admixture is defined as a material other than cement water and aggregate that is used as an ingredient of concrete and is added to the batch immediately before or during mixing. pozzolanic admixtures are siliceous or aluminous material which is themselves possess little or no cementitious value but will in finely divided form and the presence of water chemically react with calcium hydroxide liberated on hydration at ordinary temperature to form compounds possessing cementitious properties. in our experiment, we are using micro silica as an artificial pozzolan. the early age and hardened properties of cement-based systems are highly dependent on the type and dosage of chemical admixtures used [15]. a wide variety of cement admixtures are currently available to enhance the oil well cement slurry properties and achieve successful cementation. for the local cement to be effectively used for oil well cementation, it is desirable to optimize the setting time and the thickening time of the cement slurry [16]. accurate control of the thickening time and setting time is very important because a premature setting can have disastrous consequences due to loss of circulation in the well. also, too long setting time can cause possible segregation of the slurry [17]. a setting and thickening behavior can be achieved by adjusting the composition of the retarders and the accelerators [18]. million tons of waste glass is being generated annually all over the world. once the glass becomes a waste it is disposed of as landfills, which is unsustainable as this does not decompose in the environment. glass is principally composed of silica. the use of milled (ground) waste glass in concrete as a partial replacement of cement could be an important step toward the development of sustainable (environmentally friendly, energy-efficient, and economical) infrastructure systems. when waste glass is milled down to micron size particles, it is expected to undergo pozzolanic reactions with cement hydrates, forming secondary calcium silicate hydrate (c–s–h) [19]. the use of supplementary cementitious materials (scms) to offset a portion of the cement in concrete is a promising method for reducing the environmental impact from the industry. several industrial by-products have been used successfully as scms, including silica fume (sf), bauxite residue (br), and glass powder (gr). several investigators have proposed [20] these materials that are used to create blended cement which can improve concrete durability, early and long term strength, workability, and economy [21]. the goal of this work is to describe and evaluate the performance of iraqi cement produced in babel (local cement), according to the american petroleum institute (api). this analysis is an exertion for comparing the physical and chemical properties of locally factory-made cement in iraq with the imported class g cement. in other words, this effort is related to the possibility of using iraqi cement in cementing job operations in our field instead of using commercial cement. finally, this study achieves its objective of the possibility of using iraqi cement in our oil fields instead of using commercial cement without any expected and serious problems. a. h. assi and f. h. m. almahdawi / iraqi journal of chemical and petroleum engineering 22,1 (2021) 1 13 3 2materials 2.1. cement the cement used in this study is produced in recent times by the bebel cement plant (oil well cement, class g, hsr) by way of its trade name, and this type of cement is also used in cement jobs in the east baghdad field /southern zone. 2.2. water along with the experiment, the normal drinking water was used to prepare our slurry mixture. according to api specification, distilled water was used for the specimen's planning; it is deionized water with zero melted solids but through field operation, they use drinking water not distilled water. however, in a primary cementing operation, a water-to-class g cement (w/c) ratio of 0.44 is used as per the api standard which makes a cement density of approximately 15.66 lb./gal. [22]. 2.3. silicate, (silica fume) silicates structure around 75 percent of the chemical composition of cement in which the silicates be responsible for an enormous impact on the durability of cement. the silicates function is providing the strength of cement where the silicates chemically respond with different substances to transform the composition of cement [23]. additionally specifically, water wants to be added to the silicates, for instance, tricalcium silicate, to undergo hydration to release calcium ions, hydroxide ions, and large quantities of heat. micro silica, also identified as silica fume, is another sort of silicate that adds to the cement to increase durability. it is responsible for a better spreading and better volume of hydration products by declining the average size of pores in the cement paste. silica fume particles are too small that they evenly disperse among the cement to create greater bond strength as well as raise electrical resistivity, creating micro silica a good protective reinforcement for cementing job [24]. 2.4. scr -100 retarder is a non-lignosulfonate cement retarder that assistances simplify the designing of thixotropic slurries, is active in fresh water at bottom hole circulating temperature up to 250 °f (121 °c). it doesn’t source any settling problems related to non-aqueous suspensions. when treated for 24 hours at bhct, this retarder aids be responsible for exceptional compressive strength the additives levels of scr should not be higher than 4%. [25]. 2.5. hollow glass spheres (hgs) assistance to decrease slurry density without knowingly affects strength progress. it helps to reach a lighter weight slurry with high compressive strength and low density (non-foamed) the additives levels of hgs should not be higher than 3%. [25]. 2.6. halad-9 additive it is a mixture of cellulose derivative and dispersant. it makes available fluid loss control in all api classes of cement. it can be used in oil wells with bottom hole circulating temperatures (bhcts) between 60° and 300°f (15.5°c and 149°c). in most cement, the additive concentrations should be about 1% or less for providing suitable fluid-loss control [25]. 2.7. fwca it is an anti-settling polymer additive, which is used to prevent solids from settling. it is obtainable as a white solid powder that has 1.03 sp. gr, the additives levels should not be higher than 2%. [26]. 2.8. bauxite residue (br; also named "red mud") it is an unwanted product from the bayer method in constructing alumina (al2o3) as rare material for aluminum metal-making. br is an insoluble creation after bauxite digestion with sodium hydroxide. bauxite residue has a multifaceted chemical composition and contains several crystalline phases, mostly iron oxides, and hydroxides, also have aluminum hydroxides, sodalities, quartz, rutile, and many others besides some organic materials. it’s a compressive strength additive that can provide good cement bond control in high-temperature wells, mainly when used on densified cement slurries. on the other hand, the addition of bauxite residue can raise the durability of cement. most of the studies in the literature approved assure: that the strength of cement in long term falls when the levels of the additive of br are higher than 5%. [25]. 2.9. hr-5 additive a chemically improved lignosulfonate that is retards the setting of slurry. it is designed for use in oil wells that it's circulating temperatures amongst 125°c and 206°f. hr-5 additive provides increasing concentrations of hr-5 additive enhancing the expectedness of slurry thickening times.hr-5 additive drops the hazard of over-retarded slurries at the upper of a long cement column. hr-5 additive is responsible for early slurry strength development. the additives levels of this material should be equal to or less than 5% to slow the thickening time. [26]. a. h. assi and f. h. m. almahdawi / iraqi journal of chemical and petroleum engineering 22,1 (2021) 1 13 4 2.10. super plasticizer the superplasticizer that used in this paper is glenium 380. it is a novel superplasticizer, which not only appropriate for reducing the thickening time of slurry, but also for increase compressive strength. unique to its benefits, is that it can develop both early and final compressive strength. furthermore, slump preservation and workability of slurry also improved by using glenium 380, if associated with an old-style superplasticizer. superplasticizer (sp) is essential to improve the workability and setting time of slurry. also, aid to decrease shrinkage and thermal cracking. the additives levels of sp should be less than 15% of water to slow the setting rate of the slurry while keeping the flowing properties of the cement slurry. [27]. 2.11. glass powder the chemical compositions of glass powders mostly contain silica and the materials could be declared as pozzolanic material as per astm standard. glass addition can reduce the cost of cement production. a study on the durability of concrete with the waste glass pointed to better performance against chloride permeability in long term but there is concern about the alkali-silica reaction. several types of research show that at the higher age recycled glass (15%) to 20% of cement replaced) with milled waste glass powder provides compressive strengths exceeding those of control cement slurry. specific gravity and fineness of clear waste glass powders (prepared by ball mill) were 3.01 & 0.9% (#200 sieves) and the particle sizes approximately 300 μm [28]. 3experimental and slurry design are done for obtaining fitting cement slurry properties, the cement slurries were prepared according to the api standard. these properties are important for getting cement slurry that is proper for oil well-cementing operations. with the aim of control, the performances of the local iraqi cement, investigational tests were done on slurry. the experimental procedure followed for preparing the different testers is stated by the api specifications 10a. these properties are as follows: 3.1. free water free fluid assessment for challenging cement slurries used for determining slurry ability for preventing fluids separation at static conditions. extreme free fluid in cement slurry may because many problems with water pockets, channeling, sedimentation, and zonal isolation. for the measurement of free water substances, the cement slurry is equipped and conditioned typically to api specifications. next the conditioning of slurry, slurry is emptied in a graduated cylinder and covered with aluminum to stop evaporation. far along, it is subjected to 2 hours' test period. at the end of the investigation duration, a syringe is used for extracting the free water separated at the top of the slurry and the quantity of water is measured in milliliters (ml) 3.2. thickening time thickening time is a point to the era within that cement slurry stay pump able underneath well-simulated circumstances. the laboratory test situations should be representing the time, temperature, and pressure at which slurry will be exposed through pumping setups. many factors that may affect the slurry’s pump facility during a job cannot be simulated exactly through a test of thickening time which is: (fluid contamination, fluid loss to the formation, unforeseen temperature variations, and unplanned shutdowns in pumping). for determining the thickening time, the consistency of slurry is measured. the consistency, stated in bearden units of consistency (bc), is determined by the force executed by the slurry in contradiction of the paddle and dignified as a torque. the test is directed up to the time at which the slurry reaches a consistency deemed sufficient for making it unpumpable (for instance 70 or 100) bc. the slurry consistency at which the thickening-time test was finished should be recognized and reported. the approval requirement for the extreme consistency for the duration of the 15 min to 30 min stirring era should be 30 bc for cement class g. [27 and 29] 3.3. compressive strength the compressive strength test governs the integrity of cement slurry and its capability to stand long-period forced stresses. the supreme pressure used for curing is generally 3,000 psi (api), except else specified. there are two approaches for measuring the compressive strength, first by devastating and additional is by the nondestructive way. [30]. 3.4. compressive strength – ultrasonic cement analyzer uca the sonic strength test is a non-harsh test done on slurry to guess its strength. correspondences have been established to estimate the compressive strength of a slurry composition built on the time requisite for the ultrasonic signal to permit through the cement as it sets. sonic strength and crush strength signs can vary significantly contingent on the temperature of the test and slurry composition. the sonic compressive strength of cement slurry is measured by placing slurry in the autoclave part of ultrasonic cement analyzer (uca) with temperature and pressure attuned to made-up downhole circumstances, [30]. a. h. assi and f. h. m. almahdawi / iraqi journal of chemical and petroleum engineering 22,1 (2021) 1 13 5 3.5. x-ray fluorescence analysis (xrf) apparatus for elemental analysis and distribution imaging x-ray fluorescence analysis (xrf) uses characteristic x-rays (called ‘‘fluorescence x-rays’’) emitted under high-energy x-ray irradiation. xrf has some advantages in that x-ray fluorescence analysis (xrf) provides useful elemental information about cement components, is a non-destructive analytical technique used to determine the elemental composition of materials. xrf determines the chemistry of the sample by measuring the fluorescent x-rays emitted from the sample [31]. table 1 gives us the chemical composition of iraqi and omani cement in detail and table 2 gives us the chemical composition of silica fume, bauxite, and glass powder in detail. table 1. the chemical composition of iraqi and omani cement component % in iraqi cement % in omani cement %api standard mgo 1.77 0.766 0.9 al2o3 2.996 2.428 5.6 𝑺𝒊𝑶𝟐 18.63 37.58 24.66 so3 3.072 1.846 1.55 cao 69.49 57.06 61.87 mno 0.05061 0.0789 0.75 fe2o3 5.587 4.964 0.38 table 2. chemical composition silica fume, bauxite, and glass compound glass powder silica fume bauxite residue sio2 66 92 1.7 al2o3 9 1.1 53 fe2o3 <1 1.5 4.5 cao 12 0.6 2.7 mgo <1 0.9 0.7 k2o <1 – – na2o 11 – 0.03 so3 – 0.4 loi – 2 30.6 moisture – – – 3.6. rheology test the rheology influences the performance of slurry and assists in defining the pumping ability of the slurry. at rheology test, flow properties: plastic viscosity and yield point of cement slurry are definite, using a rotational viscometer for instance hpht viscometer by chandler at high-temperature conditions. principally, the cement slurry is set and conditioned conferring to api specifications. the conditioned cement is emptied in the pre-heated cylinder of viscometer, rheological parameters gotten by correlation of shear stress in contradiction of shear rate at the target temperature. the slurry rheology is tested at different temperatures, which could be more than 2, to use those data in hydraulic simulators, surface temperature, and downhole circulating temperature (simulated or from api tables) [32].600 rpm is not a portion of the process for testing the rheology of slurries. eq. (1) and eq. (2) were respectively used to calculate the plastic viscosity and yield point of the cement slurry. µp =1.5 * (ɵ300-ɵ100) (1) yp= ɵ300µp (2) where: µp: plastic viscosity of cement slurry. yp: yield point of the cement slurry. ɵ300 and, ɵ100: rotational speed of viscometer. after recording the dial readings, divide the up readings by the down readings to get their ratio. if the ratio is other than 1:1 it can be an indication the slurry may have settling or gelation problems. there may be settling problems if the readings are 5 numbers less for the down readings than for the up readings. rheology calculated by correlation of shear stress against shear rate. test data obtained with rotational viscometer rotational speeds: 300 rpm, 200 rpm, 100 rpm, 60 rpm, 30 rpm, and 6 rpm and3 rpm 3.7. fluid losses tests this test is performed as per api recommended practice for testing well cement, api does not identify ranges to follow it, but in api 65 they reference that has to be low, 46 ml/30 min is a low value, usually used for production zones. the table illustrated the amount and concentration of the designed slurry [32]. the material quantities used and the composition of the tested sample are given in table 3 table 3. experimental slurry quantities and their composition sample d omani sample c iraqi iraqi sample b iraqi sample a samples no. 792 792 792 792 cement (g) 349 349 349 349 mix water (ml) 0 30 25 0 micro silica% bwoc 0 8 8 0 bauxite % bwoc 0 50 70 0 super plasticizer (ml) 0.76 0 0 0.76 scr -100 retarder 1 0 0 1 hollow glass spheres% bwoc 1 0.05 0.05 1 halad-9 % bwoc 1 0 0 1 hr-5% bwoc 1.1 0 0 1.1 fwca% bwoc 0 25 20 0 glass powder https://www.sciencedirect.com/science/article/pii/s2212609016301157#tblfn3 https://www.sciencedirect.com/science/article/pii/s2212609016301157#tblfn3 a. h. assi and f. h. m. almahdawi / iraqi journal of chemical and petroleum engineering 22,1 (2021) 1 13 6 4results and discussion some oxides in cement for instance mgo, free cao, and so3 may reason for expansive reactions with the time that principal to a reduction in cement compressive strength. if those oxides were found in high percentages, they lead to crucial destruction of cement. from x-ray analysis iraqi cement has a mgo amount greater than omani cement, on the other hand, the percentage of cao in iraqi cement (69%) is too higher than that in omani cement (57%). so3 in iraqi cement about3.072% while in omani cement about 1.846%. the present study also was carried out to investigate the combined effect of those oxides contents in cement on the compressive strength of cement. the increase in mgo content results in a decrease in the compressive strength and a reduction in the cement durability. iraqi cement is jelly cement, so it fast thickening time, also it has low compressive strength. if it still in this statement, this type of cement gives a bad cementing job because of its low durability. the problem with iraqi cement is the low percentage of silica which is about 18.63% depending on x-ray fluorescence analysis (xrf) while in omani cement about 37.58%. using micro silica and glass powder leads to a significant increase in the amount of silica which is an important element in cement. the results of net cement show that the compressive strength tests for iraqi oil well cement class g at 38°c are good and acceptable according to the api standard specification 10a (exceeded 300 psi), while the results at 60°c are not satisfy compared to the api specification 10a (not exceeding 1500 psi). this can be attributed to the fact that high-temperature curing can get a negative impact on early strength development. iraqi cement is used at cementing jobs operation in east baghdad field, but there are some problems related to iraqi cement in this field, for example, low thickening time, poor compressive strength, etc. from 2860m to 2910m (first part of production zone): amplitude low, vdl doesn't showcasing and formation signals. thin mud signals are visible (no cement bond) squeeze cement is needed as shown in fig.1. fig.2. represents cbl (cement bond log) and vdl (variable density log) for zone cemented by using iraqi cement in well at east baghdad field. from the log it clear that the zone 3000m to 3250m in other words, production zones have cement without bond to the formation, vdl shows that the light grey areas greater than the dark grey layer that mean the bond are not good. also, the high amplitude of cbl (cement bond log) assures that meaning. vdl (variable density log) shows a straight line, no formation signal. the other zones in this log are considered partial cement because the amplitude is low and moderate and vdl shows both wiggly formation signals and straight casing signal (poor compressive strength) squeeze cement is needed if the channel is long enough fig. 1. vdl and cbl log for well in at east baghdad field from (2860 to 2910) m fig. 2. vdl and cbl log for well in at east baghdad field from (3000 to 3250) m a. h. assi and f. h. m. almahdawi / iraqi journal of chemical and petroleum engineering 22,1 (2021) 1 13 7 since the problem of the strength of the compression of cement was the weakness of the iraqi cement, which was evident from the tests of pure cement. i have two temperatures of 38 and 60 degrees celsius, so in our research, we focused on this characteristic more than others. fig. 3 represents the effect of adding micro silica on the compressive strength of cement, and through it, we note that the higher the percentage of micro silica, the greater the value of the compressive strength of the cement. it should be noted that micro-silica was used as an additive and not as it was used before by al-jumailya et al. as a replacement material for cement, which led to increase compressive strength and reduce free water to zero, silica reacts with cement component and hydrates very slowly, and contributes mainly to the long-term strength. fig. 4 represents the effect of adding bauxite on the compressive strength of the cement, the reason behind that is that bauxite has a high percentage of alumina about 53% that react with cement component and hydrates very rapidly and produces most of the heat of hydration and early strength observed during the first few days. we note that the proportion is direct when the bauxite ratio is less than 8 percent compared to what was found before, from rajendran et al., who founded that the bauxite ratio should not exceed 5%. we observe a rapid decrease in the compressive strength of the cement when the bauxite ratio is higher than 8 percent. fig. 5 illustrates the effect of glass powder on the compressive strength of cement, where we note that the proportionality is proportional when the ratio of the glass powder is less or equal to 25 percent and vice versa. this is close to what has been proven before by andreola et al because the high percentage of silica in glass powder about 66%, which is thought to be the major contributor to long-term strength. fig. 6 summarizes the effect of adding a superplasticizer on the value of compressive strength as the compressive strength of cement increases if the percentage of superplasticizer is less or equal to 20%. this result is slightly greater than what was obtained before by collepardi et al. it should be noted that a superplasticizer has been added to obtain pumpable cement slurry and to delay the thickening time to enable the cement slurry to reach the appropriate place. on the other hand, the addition of micro silica and bauxite leads to a reduction of the thickening time for the cementing process. the superplasticizer was used to treat these effects tri calcium aluminate c3a and as shown in fig. 7. it should be noted, that the powdered glass substance is considered an inert material that has no significant effect on the time the cement thickens. its effect is only by increasing the compressive strength of the cement because it fills the voids that may occur in the cement and thus increases the durability and strength of the cement. fig. 3. the effect of micro silica on compressive strength of cement slurry at 60°c and 38°c fig. 4. the effect of br on compressive strength of cement slurry at 60°c and 38°c fig. 5. the effect of glass powder on compressive strength of cement slurry at 60 °c and 38°c fig. 6. the effect of sp on compressive strength of cement slurry at 60°c and38°c 0 500 1000 1500 2000 2500 0 5 10 15 20 25 30 35 c o m p re ss iv e s tr e n g th p si silica fume % bwoc compressive strength at 60 °c,8hr. curing compressive strength at 38° c,8hr. curing 0 200 400 600 800 1000 1200 1400 1600 1800 0 2 4 6 8 10 12 14 16 c o m p re ss iv e s tr e n g th p si br % bwoc compressive strength at 60 °c ,8hr. curing compressive strength at 38 °c ,8hr. curing 0 200 400 600 800 1000 1200 1400 1600 1800 0 5 10 15 20 25 30 35 c o m p re ss iv e s tr e n g th p si glass powder % bwoc compressive strength at 60 °c ,8.hr. curing compressive strength at 38 °c ,8.hr. curing 0 500 1000 1500 2000 2500 0 5 10 15 20 25 30 c o m p re ss iv e s tr e n g th p si sp % of water compressive strength at 60 °c,8hr. curing compressive strength at 38° c,8hr. curing a. h. assi and f. h. m. almahdawi / iraqi journal of chemical and petroleum engineering 22,1 (2021) 1 13 8 fig. 7. the effect of superplasticizer on thickening time at pr.=5200psi, t=52°c table 4 and table 5 show us the results of testing the designed slurry, the iraqi cement was prepared into three samples which are a, b, and, c while sample d represents omani cement. net iraqi cement was also tested to make a complete comparison between all tested samples. samples b and d were prepared using waste material and superplasticizer, while samples a and d were prepared using conventional additives. sample c has the maximum value of plastic viscosity and the lowermost value of yield point due to the presence of 30% bwoc micro silica, 25% bwoc glass powder, and 15%super plasticizer, and 5% bauxite. all those materials led to give good cement compressive strength for both temperatures 60 and38°c. sample b gave the lesser density value comparing with the other tested samples because of the high value of sp which is about 20% from water, on the other hand, this sample gave a high value of thickening time due to the high value of sp which is about 20% and slightly low value of silica fume which is about 20% bwoc. furthermore, the consequences indicate that there are decreases in the value of density after adding micro silica, superplasticizer. sample a gives the highest free water and fluid losses respectively, also this sample gave the lowermost thickening time all that due to the presence of conventional cement additives. however, sample d that represents omani cement gave high thickening time and compressive strength respectively than sample a. finally, it can be said that omani cement showed good performance compared to iraqi cement after adding traditional additives, but both of them showed good results for all the properties of cement, especially the compressive strength. on the other hand, the added waste enabled iraqi cement to perform much better than omani cement. since iraqi cement shows the lowest compressive strength value and this is one of the main problems for iraqi cement, sample c shows the best performance because it gave the highest compressive strength and this is considered an excellent design for cement mortar because it solves the iraqi cement problem as shown in fig. 8 and fig. 9. table 4. result of the cement slurry design free water% thickening time, min pr=5200, t=52° compressive strength psi at 60°c 8.hr. curing compressive strength psi at 38 °c,8 hr. curing sample no. 1.5 90 2300 400 sample a 0.1 115 2320 800 sample b 0 103 2600 990 sample c 1.05 110 2400 450 sample d 5.9 90-120 1500 300 api standard 2.5 95 1162 300 net cement table 5. result of the cement slurry design at bottom hole circulating temperature bhct of 133f density gm/cc yp lb./100ft 2 pv cp fluid losses ml./30 min sample no. 1.5 24 46 29 sample a 1.77 23 42 27 sample b 1.78 20 47 22 sample c 1.75 23 38 20 sample d 1.88 37 51 42 net cement fig. 8. compressive strength results comparison at 60 °c and 8.hr. curing fig. 9. compressive strength results comparison at 38 °c and 8.hr. curing 78 83 88 93 98 103 108 113 118 0 5 10 15 20 25 30 35 t h ic k e n in g t im e , m in silica fume and bauxiate % thickening time min, silica fume only thickening time min, bauxite only thickening time min, silica fume +20% super placitizer thickening time min, bauxite +20% super placitizer 2300 2320 2680 2400 1162 api 0 500 1000 1500 2000 2500 3000 sample a sample b sample c sample d net cement c o m p r e s s iv e s t r e n g t h p s i a. h. assi and f. h. m. almahdawi / iraqi journal of chemical and petroleum engineering 22,1 (2021) 1 13 9 4.1. cemcade results a pre-job simulation is used for making guesses regarding the performance of the cement slurry to use it as well as the bottom hole and surface pressures to expect through the job. significantly, perfect well data is used as input into this simulator. on the other hand, simulations supply a very good estimate of the conditions that are prospective to prevail through the implementation of a job. currently, there are several marketable simulators on the market that offer an inclusive suite of applications that handle many wellbore configurations and slurry rheological models. cemcade is fully combined software covering different modules where all features of a cement job are accounted for dynamic graphics are automatically updated with any change of data and several independent computers further for helping the user picking the suitable cementing job factors. from cemcade program. sample c as tail slurry because of its density about 1.78 gm/cc and sample a is lead slurry because its density about 1.5 gm/cc. since sample c gives the best performance of slurry design comparing with the other tested samples related to the compressive strength results, we chose it as an extraordinary sample to represent its results in the cemcade program as tail slurry, furthermore, sample a shows good performance and its chosen as lead slurry. information on cement slurry must be entered into the program for both selected samples, which are sample a as lead and sample c as a tail from the experimental results for those samples from table 4 and table 5. in addition to that, information regarding the well or section to be cemented must be entered as found in table 6. table 6. design parameters for production casing well information values open hole depth 2560 m casing depth to be cemented 2557m od/id of the casing 7/6.185 in open-hole interval, as per caliper 8.9869 in od/id previous casing size 9.625/8.7 in previous casing shoe depth 2036 m top of lead 1355m top of tail 1936m cased hole lead excess 0% open hole tail excess 30% bhst/bhct 79/56 ͦ c no .of centralizers 99 fig. 10.shows the rheological behavior of a lead and tail cement slurry measured using a fann vg meter. the shear stress shear rate response was curved fitted using the herschel – bulkley, where k=1.58e-2 and k=1. 44e-2 lbf.s /ft2,n= 0.75 and n= 0.87 , ty=11.25 lb./100ft2 and ty=10.88 lb./100ft2 for tail and lead slurries respectively. also, this figure represents the rheology of all used fluids and it clear that the cement is followed by modified power low the herschel – bulkley fluids combine the characteristics of power-law and bingham fluids. thus, there is minimum stress required for flow initiation but above that, the shear stress/shear rate relationship is similar to that of a bingham fluid. the equations that describe the behavior of herschel – bulkley fluids are as follows in eq. 3: 𝜏= 𝜏𝑦+ 𝑘𝛾𝑛 𝑤ℎ𝑒𝑛 𝜏> 𝜏𝑦 (3) where: 𝜏=shear stress lb/100ft 2 , k= consitency lb/100ft 2 , n= flow index, 𝛾= shear rate rpm fig. 10. compressible rheology parameters displayed at p=1 atm and t=20° c (65°f) fig. 11. average fluid concentration a. h. assi and f. h. m. almahdawi / iraqi journal of chemical and petroleum engineering 22,1 (2021) 1 13 10 fig. 11 and fig. 12 showed the distribution of cement slurry in the annular space and casing. the cement slurry was distributed well as planned upon entering the information for the program except for a small transition area from 1900 meters to 2000 meters. from the color of the concentrations of liquids distributed in the annular void, there is no contamination between the fluid and channels, all that is a good indication of the presence of a good cementitious bond. fig. 12. average fluid concentration also, from fig. 13, the compressive strength is obtained by ultrasound of sample c of a cement slurry which is about 2,691 psi after 24 hours. handling is at 70 ° c, which is close to the device's measured value of 2,600 psi. from fig. 14, an assay of sample c shows hpht cement at conditions of 5500 psi and 177 ° c for 7 hours. the cement was still pumpable and gave a consistency of 30 bc for three hours, which is the preferred field value fig. 13. compressive strength for sample c from the usa after 24hr. curing and at 70°c fig. 14. hpht curing for sample c slurry cement at 5500 psi and 177 ° c for 7hr 5conclusion in keeping with the consequences acquired in this study, the following can be clinched; from xrf results, iraqi cement has a high amount of these oxides: mgo, cao, so3and fe2o3 comparing with the standard api. that high oxide content in cement generally results in a decrease in compressive strength and durability; adding bauxite inhibits the bad effect of an increasing the amount of mgo, cao, so3and fe2o3 oxides in iraqi cement and give us more sulfate resistance slurry. but the levels of the additive of br should be less than 8% bwoc; from xrf results, iraqi cement has a low value of sio2 which is about 18.63% paralleling with the standard api, adding micro silica and glass powder lead to increase the extent of silica in iraqi cement because these materials have a high amount of silica and that attributed to improving compressive strength and, at the same time, it reduces the free water percentage to zero; addition of superplasticizer (sp) is vital to develop the workability of slurry and increasing thickening time with the attendance of silica fume and bauxite. the additives levels of sp should be equal to or less than 20% from the used water to slow the setting rate of the slurry while keeping the flowing properties of the cement slurry. the result of compressive strength for net cement sample at 60°c is not satisfied compared to the api specification 10a (not exceeding 1500 psi). this can be attributed to the fact that the high-temperature curing can get a negative impact on early strength development, but after adding micro silica, superplasticizer, glass powder, and bauxite, iraqi cement gave high compressive strength better than omani cement as in sample c; adding micro silica and superplasticizer (sp) together lead to a slightly decrease in the value of slurry density but still in acceptable range; from cemcade results, sample c gave the best and good fluid distribution inside the pipe and in the annulus, and that be considered one of the indicators of good cement bond and no any contamination between the used fluids; a. h. assi and f. h. m. almahdawi / iraqi journal of chemical and petroleum engineering 22,1 (2021) 1 13 11 the other conventional additive which is: (scr -100 retarder, hr-5, fwca, hollow glass spheres (hgs), and halad-9) that currently used in our fields in the south of iraq play an important role to enhance and design special slurry be able to stand over downhole circumstance from temperature and pressure and sour gases; the laboratory test for compressive strength show that at the stage of above 25% of glass powder there are rabidly decline in the value of compressive strength, so the optimum value should be equal or below 25%. the results of the program cemcade proved to be the sample a and c showed good performance through high cement bonding and ideal distribution of fluids designed to accomplish the cementing process. acknowledgments the authors are very grateful to the head of cement section in petroleum r&d center mr. qasim abdulridha khalti, also the authors are very grateful to senior engineer ahmed abdulah haiwi from basra oil company (boc) for his support. references [1] d. ibrahim and f. h. m. almahdawi, “addition of super absorbent polymer for upgrading of cement quality in iraqi oil wells”, ijcpe, vol. 17, no. 3, pp. 83-90, sep. 2016. [2] a. assi, “potato starch for enhancing the properties of the drilling fluids”, ijcpe, vol. 19, no. 3, pp. 3340, sep. 2018. [3] american petroleum institute (api). specification 10a. "specification for cement and materials for well cementing". american petroleum institute, api/ansi/iso 10426-1-2001. washington, dc, 2002. [4] ravi, k., bosma, m., & gastebled, o. "improve the economics of oil and gas wells by reducing the risk of cement failure", iadc/spe drilling conference, dallas, texas, february, paper spe 74497, 2002. [5] sandeep kumar pedam." determining strength parameters of oil well cement",university of texas at austin, 2007. [6] astm c 348 ." standard test method for flexural strength of hydrauliccement mortars ", annual book of astm standard, vol.04-01, 2002. [7] astm c c191. " time of setting of hydraulic cement by vicat needle", annual book of astm stand. vol.04 no.01, 2008. [8] zhou y, jia j ."a new type cement slurry system for deep and high temperature wells". ejge 15:1989– 1995,2010. [9] adeleye jo, salam kk, adetunde ia ."analysis of rheological properties of treated nigerian clay using factorial design". eur j sci res,vol.37 no.3: 426– 438, 2009. [10] american petroleum institute (api) ." api recommended practice 10b, recommended practice for testing well cement". exploration and production department, 22nd edn,1997. [11] bayu s, muhammed tf, t roby . "effect of lignosulfonate and temperature on compressive strength of cement" .proceedings of world geothermal congress 2010 bali, indonesia, pp 1–3, 2010. [12] herianto a, fathaddin mt. "effects of additives and conditioning time on comprehensive and shear bond strengths of geothermal well cement". proceedings of world geothermal congress. antalya, turkey, pp 1–7, 2005. [13] hind a r, bhargava s k & grocott s c."the surface chemistry of bayer process solids: a review". colloids and surfaces; a: physiochemical and engineering aspects, no. 146: 359-374,1998. [14] yang j & xiao b. "development of unsintered construction materials from red mud wastes produced in the sintering alumina process". construction and building materials, vol. 22 no. 12: 2299-2307, 2008. [15] rajendran r r, pillaib e b & santhakumai a r. "effective utilization of redmud bauxite waste as a replacement of cement in concrete for environmental conservation". ecology, environment and conservation, vol. 19 : 247-255, 2013. [16] kótai l, sajó i, gács i, papp k, bartha a & bánvölgyi g. "an environmentally friendly method for removing sodium in red mud". chemistry letters chem lett, vol. 35: 1278-1279, 2006. [17] collepardi m., monosi s. and pauri m. "the influence of superplasticizer type and dosage on the compressive strength of portand cement concrete in the presence of fly ash", 1990. [18] gopalan, m. k., and m. n. haque. "strength development of superplasticized plain and fly ash concretes." in admixtures for concreteimprovement of properties: proceedings of the international rilem symposium, vol. 5, p. 208. crc press, 1990. [19] f. andreola, l. barbieri, i. lancellotti, c. leonelli, t. manfredini "recycling of industrial wastes in ceramic manufacturing". state of art and glass case studies, ceram. int., vol.42 : 13333-13338, 2016. [20] a. assi, “enhancing the lifting capacity of drilling fluids in vertical oil wells”, ijcpe, vol. 18, no. 3, pp. 13-29, sep. 2017. [21] r.k. dhir, m.d. newlands, j.e. halliday (eds.). "re cycling and reuse of waste materials". thomas telford ltd., london, united kingdom, pp. 827-838, 2003 [22] l. strüder, n. meidinger, d. stotter, j. kemmer, p. lechner, p. leutenegger, h. soltau, f. eggert, m. rhode, t. schülein. "high-resolution x-ray spectroscopy close to room temperature”. microsc. microanal, vol. 4: 622–631, 1999. https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/215 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/215 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/215 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/215 https://doi.org/10.31699/ijcpe.2018.3.4 https://doi.org/10.31699/ijcpe.2018.3.4 https://doi.org/10.31699/ijcpe.2018.3.4 https://onepetro.org/spedc/proceedings-abstract/02dc/all-02dc/spe-74497-ms/136919 https://onepetro.org/spedc/proceedings-abstract/02dc/all-02dc/spe-74497-ms/136919 https://onepetro.org/spedc/proceedings-abstract/02dc/all-02dc/spe-74497-ms/136919 https://onepetro.org/spedc/proceedings-abstract/02dc/all-02dc/spe-74497-ms/136919 https://onepetro.org/spedc/proceedings-abstract/02dc/all-02dc/spe-74497-ms/136919 https://repositories.lib.utexas.edu/handle/2152/61365 https://repositories.lib.utexas.edu/handle/2152/61365 https://repositories.lib.utexas.edu/handle/2152/61365 http://ejge.com/2010/ppr10.146.pdf http://ejge.com/2010/ppr10.146.pdf http://ejge.com/2010/ppr10.146.pdf https://d1wqtxts1xzle7.cloudfront.net/31178538/ejsr_37_3_07.pdf?1366868319=&response-content-disposition=inline%3b+filename%3danalysis_of_rheological_properties_of_tr.pdf&expires=1616096622&signature=luem60twbonheicwgsyzgflanzd9ycc-w7wruvtnpccnrxc7kbcl5ngbbt-9ekrh7m7dn52gv6slprsr9sip5whga3ncafjdrmewu4bd79noroiokphmb9k1mko5gonadx-177w0n6hm055avjtmwyqxtljfmxu87olsp~eciktsyp5aadr5ldsi3hvkdstl8kwwcyzeemk6v88dl3mz4mopqtmfi4olo3nhuq9j3al3zapcuveurp3hy4ozww2qbuknqziydkgonbo94ls8b-eztxbplqrppxcoacfa2hynr5awqjov4vydii5dpyq18ziq5fomegfmzge1bdacta__&key-pair-id=apkajlohf5ggslrbv4za https://d1wqtxts1xzle7.cloudfront.net/31178538/ejsr_37_3_07.pdf?1366868319=&response-content-disposition=inline%3b+filename%3danalysis_of_rheological_properties_of_tr.pdf&expires=1616096622&signature=luem60twbonheicwgsyzgflanzd9ycc-w7wruvtnpccnrxc7kbcl5ngbbt-9ekrh7m7dn52gv6slprsr9sip5whga3ncafjdrmewu4bd79noroiokphmb9k1mko5gonadx-177w0n6hm055avjtmwyqxtljfmxu87olsp~eciktsyp5aadr5ldsi3hvkdstl8kwwcyzeemk6v88dl3mz4mopqtmfi4olo3nhuq9j3al3zapcuveurp3hy4ozww2qbuknqziydkgonbo94ls8b-eztxbplqrppxcoacfa2hynr5awqjov4vydii5dpyq18ziq5fomegfmzge1bdacta__&key-pair-id=apkajlohf5ggslrbv4za https://d1wqtxts1xzle7.cloudfront.net/31178538/ejsr_37_3_07.pdf?1366868319=&response-content-disposition=inline%3b+filename%3danalysis_of_rheological_properties_of_tr.pdf&expires=1616096622&signature=luem60twbonheicwgsyzgflanzd9ycc-w7wruvtnpccnrxc7kbcl5ngbbt-9ekrh7m7dn52gv6slprsr9sip5whga3ncafjdrmewu4bd79noroiokphmb9k1mko5gonadx-177w0n6hm055avjtmwyqxtljfmxu87olsp~eciktsyp5aadr5ldsi3hvkdstl8kwwcyzeemk6v88dl3mz4mopqtmfi4olo3nhuq9j3al3zapcuveurp3hy4ozww2qbuknqziydkgonbo94ls8b-eztxbplqrppxcoacfa2hynr5awqjov4vydii5dpyq18ziq5fomegfmzge1bdacta__&key-pair-id=apkajlohf5ggslrbv4za https://d1wqtxts1xzle7.cloudfront.net/31178538/ejsr_37_3_07.pdf?1366868319=&response-content-disposition=inline%3b+filename%3danalysis_of_rheological_properties_of_tr.pdf&expires=1616096622&signature=luem60twbonheicwgsyzgflanzd9ycc-w7wruvtnpccnrxc7kbcl5ngbbt-9ekrh7m7dn52gv6slprsr9sip5whga3ncafjdrmewu4bd79noroiokphmb9k1mko5gonadx-177w0n6hm055avjtmwyqxtljfmxu87olsp~eciktsyp5aadr5ldsi3hvkdstl8kwwcyzeemk6v88dl3mz4mopqtmfi4olo3nhuq9j3al3zapcuveurp3hy4ozww2qbuknqziydkgonbo94ls8b-eztxbplqrppxcoacfa2hynr5awqjov4vydii5dpyq18ziq5fomegfmzge1bdacta__&key-pair-id=apkajlohf5ggslrbv4za https://www.geothermal-energy.org/pdf/igastandard/wgc/2010/2134.pdf https://www.geothermal-energy.org/pdf/igastandard/wgc/2010/2134.pdf https://www.geothermal-energy.org/pdf/igastandard/wgc/2010/2134.pdf https://www.geothermal-energy.org/pdf/igastandard/wgc/2010/2134.pdf https://www.geothermal-energy.org/pdf/igastandard/wgc/2010/2134.pdf https://www.sciencedirect.com/science/article/abs/pii/s0927775798007985 https://www.sciencedirect.com/science/article/abs/pii/s0927775798007985 https://www.sciencedirect.com/science/article/abs/pii/s0927775798007985 https://www.sciencedirect.com/science/article/abs/pii/s0927775798007985 https://www.sciencedirect.com/science/article/abs/pii/s0950061807002425 https://www.sciencedirect.com/science/article/abs/pii/s0950061807002425 https://www.sciencedirect.com/science/article/abs/pii/s0950061807002425 https://www.sciencedirect.com/science/article/abs/pii/s0950061807002425 https://www.sciencedirect.com/science/article/abs/pii/s0950061807002425 https://www.researchgate.net/profile/rathan-raj-rajendran/publication/286198519_effective_utilization_of_redmud_bauxite_waste_as_a_replacement_of_cement_in_concrete_for_environmental_conservation/links/5810516108aea04bbcba6b71/effective-utilization-of-redmud-bauxite-waste-as-a-replacement-of-cement-in-concrete-for-environmental-conservation.pdf https://www.researchgate.net/profile/rathan-raj-rajendran/publication/286198519_effective_utilization_of_redmud_bauxite_waste_as_a_replacement_of_cement_in_concrete_for_environmental_conservation/links/5810516108aea04bbcba6b71/effective-utilization-of-redmud-bauxite-waste-as-a-replacement-of-cement-in-concrete-for-environmental-conservation.pdf https://www.researchgate.net/profile/rathan-raj-rajendran/publication/286198519_effective_utilization_of_redmud_bauxite_waste_as_a_replacement_of_cement_in_concrete_for_environmental_conservation/links/5810516108aea04bbcba6b71/effective-utilization-of-redmud-bauxite-waste-as-a-replacement-of-cement-in-concrete-for-environmental-conservation.pdf https://www.researchgate.net/profile/rathan-raj-rajendran/publication/286198519_effective_utilization_of_redmud_bauxite_waste_as_a_replacement_of_cement_in_concrete_for_environmental_conservation/links/5810516108aea04bbcba6b71/effective-utilization-of-redmud-bauxite-waste-as-a-replacement-of-cement-in-concrete-for-environmental-conservation.pdf https://www.researchgate.net/profile/rathan-raj-rajendran/publication/286198519_effective_utilization_of_redmud_bauxite_waste_as_a_replacement_of_cement_in_concrete_for_environmental_conservation/links/5810516108aea04bbcba6b71/effective-utilization-of-redmud-bauxite-waste-as-a-replacement-of-cement-in-concrete-for-environmental-conservation.pdf https://www.journal.csj.jp/doi/abs/10.1246/cl.2006.1278 https://www.journal.csj.jp/doi/abs/10.1246/cl.2006.1278 https://www.journal.csj.jp/doi/abs/10.1246/cl.2006.1278 https://www.journal.csj.jp/doi/abs/10.1246/cl.2006.1278 https://trid.trb.org/view/360687 https://trid.trb.org/view/360687 https://trid.trb.org/view/360687 https://trid.trb.org/view/360687 https://books.google.iq/books?hl=en&lr=&id=punzdwaaqbaj&oi=fnd&pg=pa183&dq=strength+development+of+superplasticized+plain+and+fly+ash++concretes&ots=lz4pjv50ca&sig=asko1morc5hzofosxbrajrjoask&redir_esc=y#v=onepage&q=strength%20development%20of%20superplasticized%20plain%20and%20fly%20ash%20%20concretes&f=false https://books.google.iq/books?hl=en&lr=&id=punzdwaaqbaj&oi=fnd&pg=pa183&dq=strength+development+of+superplasticized+plain+and+fly+ash++concretes&ots=lz4pjv50ca&sig=asko1morc5hzofosxbrajrjoask&redir_esc=y#v=onepage&q=strength%20development%20of%20superplasticized%20plain%20and%20fly%20ash%20%20concretes&f=false https://books.google.iq/books?hl=en&lr=&id=punzdwaaqbaj&oi=fnd&pg=pa183&dq=strength+development+of+superplasticized+plain+and+fly+ash++concretes&ots=lz4pjv50ca&sig=asko1morc5hzofosxbrajrjoask&redir_esc=y#v=onepage&q=strength%20development%20of%20superplasticized%20plain%20and%20fly%20ash%20%20concretes&f=false https://books.google.iq/books?hl=en&lr=&id=punzdwaaqbaj&oi=fnd&pg=pa183&dq=strength+development+of+superplasticized+plain+and+fly+ash++concretes&ots=lz4pjv50ca&sig=asko1morc5hzofosxbrajrjoask&redir_esc=y#v=onepage&q=strength%20development%20of%20superplasticized%20plain%20and%20fly%20ash%20%20concretes&f=false https://books.google.iq/books?hl=en&lr=&id=punzdwaaqbaj&oi=fnd&pg=pa183&dq=strength+development+of+superplasticized+plain+and+fly+ash++concretes&ots=lz4pjv50ca&sig=asko1morc5hzofosxbrajrjoask&redir_esc=y#v=onepage&q=strength%20development%20of%20superplasticized%20plain%20and%20fly%20ash%20%20concretes&f=false https://books.google.iq/books?hl=en&lr=&id=punzdwaaqbaj&oi=fnd&pg=pa183&dq=strength+development+of+superplasticized+plain+and+fly+ash++concretes&ots=lz4pjv50ca&sig=asko1morc5hzofosxbrajrjoask&redir_esc=y#v=onepage&q=strength%20development%20of%20superplasticized%20plain%20and%20fly%20ash%20%20concretes&f=false https://www.sciencedirect.com/science/article/pii/s0272884216308240 https://www.sciencedirect.com/science/article/pii/s0272884216308240 https://www.sciencedirect.com/science/article/pii/s0272884216308240 https://www.sciencedirect.com/science/article/pii/s0272884216308240 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/63 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/63 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/63 https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.469.6821&rep=rep1&type=pdf https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.469.6821&rep=rep1&type=pdf https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.469.6821&rep=rep1&type=pdf https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.469.6821&rep=rep1&type=pdf https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.469.6821&rep=rep1&type=pdf a. h. assi and f. h. m. almahdawi / iraqi journal of chemical and petroleum engineering 22,1 (2021) 1 13 12 [23] "silica fume manual". oriental trexim pvt. ltd. ,2003. [24] v.bhikshma, k.nitturkar and y.venkatesham. "investigations on mechanical properties of high strength silica fume concrete”. asian journal of civil engineering (building and housing), vol.10 no.3: 335-346, 2009. [25] arina binti sauki and sonny irawan. "effects of pressure and temperature on well cement degradation by supercritical co2".international journal of engineerig & technology ijet-ijens, vol.10 no.4, 2010. [26] abdullah a. almusallam, hamoud beshr, mohammed maslehuddin and omar s.b. alamoudi. "effect of silica fume on the mechanical properties of low quality coarse aggregate concrete".cement and concrete composites, vol.26: 891–900, 2004. [27] american petroleum institute (api). specification 10a. "specification for cement and materials for well cementing". american petroleum institute.api/ansi/iso 10426-1. washington, dc: 2002. [28] al-jumailya, i.a.s., najib, n., kareem, q."an overview on the influence of pozzolanic materials on properties of concrete". int. j. enhanc. res. sci. technol. eng, vol.4: 81–92. ,2015. [29] bourgoyne a.t. jr., millheim k.k., chenevert m.e., and young f.s. "applied drilling engineering", society of petroleum engineers text book series. vol.1, richardson, tx, 1986. [30] bush, g., and o'donnell, k."global cementing best practices, occidental oil and gas corp".global drilling community, 65 pp., 2007. [31] assi, a.h . "the effect of some materials on funnel viscosityreading in water base mud". iraqi geological journal, vol.53 no.1e: 32-43, 2020. [32] santra, a., reddy b. r., & antia, m.. "designing cement slurries for preventing formation fluid influx after placement". paper spe 106006 presented at the spe international symposium on oilfield chemistry held in houston, texas, u.s.a., 28 february-2 march.,2007. https://www.sid.ir/en/journal/viewpaper.aspx?id=250185 https://www.sid.ir/en/journal/viewpaper.aspx?id=250185 https://www.sid.ir/en/journal/viewpaper.aspx?id=250185 https://www.sid.ir/en/journal/viewpaper.aspx?id=250185 https://www.sid.ir/en/journal/viewpaper.aspx?id=250185 http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.225.7747&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.225.7747&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.225.7747&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.225.7747&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.225.7747&rep=rep1&type=pdf https://www.sciencedirect.com/science/article/abs/pii/s0958946503001859 https://www.sciencedirect.com/science/article/abs/pii/s0958946503001859 https://www.sciencedirect.com/science/article/abs/pii/s0958946503001859 https://www.sciencedirect.com/science/article/abs/pii/s0958946503001859 https://www.sciencedirect.com/science/article/abs/pii/s0958946503001859 https://www.sciencedirect.com/science/article/abs/pii/s0958946503001859 https://store.spe.org/applied-drilling-engineering-p10.aspx https://store.spe.org/applied-drilling-engineering-p10.aspx https://store.spe.org/applied-drilling-engineering-p10.aspx https://store.spe.org/applied-drilling-engineering-p10.aspx http://igj-iraq.org/igj/index.php/igj/article/view/190 http://igj-iraq.org/igj/index.php/igj/article/view/190 http://igj-iraq.org/igj/index.php/igj/article/view/190 https://onepetro.org/speocc/proceedings-abstract/07ocs/all-07ocs/spe-106006-ms/143540 https://onepetro.org/speocc/proceedings-abstract/07ocs/all-07ocs/spe-106006-ms/143540 https://onepetro.org/speocc/proceedings-abstract/07ocs/all-07ocs/spe-106006-ms/143540 https://onepetro.org/speocc/proceedings-abstract/07ocs/all-07ocs/spe-106006-ms/143540 https://onepetro.org/speocc/proceedings-abstract/07ocs/all-07ocs/spe-106006-ms/143540 https://onepetro.org/speocc/proceedings-abstract/07ocs/all-07ocs/spe-106006-ms/143540 a. h. assi and f. h. m. almahdawi / iraqi journal of chemical and petroleum engineering 22,1 (2021) 1 13 13 المحلي العراقي باالسمنت المستورد لتصميم مالط السمنت البار تقييم ادائية االسمنت النفط العراقية فالح حسن محمدو امل حبيب عاصي جامعه بغداد–كليه الهندسه -قسم هندسة النفط الخالصة يتعلق هذا الجهد بوصف وتقييم أداء عينة األسمنت العراقية المخطط لها لوظائف تدعيم آبار النفط في العراق. في هذا البحث ، تم اختبار الخصائص الرئيسية لألسمنت وهي زمن التثخين وقوة الضغط والمياه الحرة باإلضافة إلى الخواص ي. تشير العواقب إلى أن األسمنت العراقي بعد إضافات تجريب بشكل محددة ظروف ظل في األسمنتاالنسيابية وفلترة مالط يوجد في هذا البحث تحقيق مقارن ويمكن بالتالي استخدامه في تدعيم وظائف آبار النفط. apiخاصة يلبي متطلبات معايير دخان السيليكا والبوكسيت تم إجراؤه على عمل تجريبي حول فعالية بعض المواد المضافة التي تعتبر مواد نفايات وهي ، الكرات الزجاجية المجوفة scr -100 retarder ،hr-5 ،fwcaومسحوق الزجاج ومضافات تقليدية أخرى وهي: ) (hgs) وhalad-9 .التي تستخدم حالًيا في حقولنا على األسمنت العراقي المحلي ووضع نتائج األسمنت األجنبية كمحافظ الكيميائي لألسمنت العراقي واألسمنت المستورد وعينات النفايات باستخدام تقنية حيود االشعه تم تحديد عينات التحليل ووجدت اختالفات طفيفة في التركيب بين تلك العينات .واعتماًدا على نتائج األشعة السينية ، نقوم باختيار اإلضافات السينيه أن األسمنت العراقي يحتوي باستخدام تقنية حيود االشعه السينيهالمناسبة لتحضير األسمنت عينات الطين. أظهرت النتائج ٪. فحص هذا البحث 37.58٪ بينما في األسمنت العماني حوالي 18.63على نسبة منخفضة من السيليكا تبلغ حوالي ائج أن إضافة . أظهرت النتمستدام أسمنتيإمكانات السيليكا الدقيقة والبوكسيت ومسحوق الزجاج المخلفات إلنتاج مالط ميكرو سيليكا والبوكسيت يحسن من أداء األسمنت العراقي ولكنه يؤدي أيضا إلى انخفاض طفيف في وقت التثخين. لتجنب هذه المشكلة ، يتم استخدام الملدنات الفائقة لجعل عملية ضخ األسمنت أكثر سهولة ، بمعنى آخر زيادة وقت التثخين وزيادة ، فإن إضافة مسحوق الزجاج يزيد من قيمة مقاومة االنضغاط. يتم استخدام كل من المضافات قوة الضغط. عالوة على ذلك العراقي األسمنت أداء وتعزز تزيد النفايات إضافة ولكن ، أفضل)النفايات والتقليدية( لتصميم المالط لتحقيق خصائص مالط منت التجاري. اعتماًدا على نتائج اختبار مقاومة األس من فعالية أكثر يجعلها مما ، آخر بمعنى ، التقليدية باإلضافات مقارنة االنضغاط ، تم العثور على التركيز األمثل لمواد النفايات المستخدمة في هذا البحث ، ثم تم استخدام التركيز األمثل إلعداد كفاءة أعمال لتحسين واعدة وسيلة يعد األسمنتعينات األسمنت. أظهرت النتائج أن استخدام المخلفات لتحضير مالط أظهرت أداًء c و a أن العينة cemcade أثبتت نتائج برنامج األسمنت وتقليل األثر البيئي السلبي الناتج عن الصناعة. جيًدا من خالل الترابط األسمنتي العالي والتوزيع المثالي للسوائل المصممة إلنجاز عملية التدعيم. العراقي, اضافات, تصميم الوحل , خواص االسمنت, االسمنت التجاري.: السمنت دالةالكلمات ال available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net iraqi journal of chemical and petroleum engineering vol. 24 no.1 (march 2023) 89 – 95 eissn: 2618-0707, pissn: 1997-4884 *corresponding author: name: athraa f. hasan, email: athraafalah@gmail.com ijcpe is licensed under a creative commons attribution-noncommercial 4.0 international license. correlation of insulin like growth factor-1 and insulin-like growth factor binding protein with lh, fsh and testosterone in iraqi children with growth hormone deficiency athraa f. hasan a, *, bushra f. hassan a, abdilkareem y. alsameraie b a university of baghdad, college of science for women, department chemistry, al-jadriya, baghdad, iraq b national diabetic center for treatment and research, al-mustansiriyah university, baghdad, iraq abstract insulin like growth factor-1 has metabolic and growth-related roles all over the body and is strongly associated and regulated by growth hormone. it is produced by almost any type of tissue, especially the liver. the study aimed to measure insulin like growth factor in growth hormone deficient patients and find its relation with other studied parameters. the subjects in the study were 180 studied in the national diabetic center for treatment and research/al-mustansiriya university in baghdad/iraq for the period from november 2021 to april 2022. blood was drawn and investigated for the levels of igf-1, igfbp-3, lh, and fsh. also testosterone and statistical analysis was carried out to find the potential correlations. the results relived that the gender was not affect the levels of either parameter, igf-1 was found to be positively correlated with age, bmi, and igfbp-3. while igfbp-3 was found to be positively correlated with the levels of igf-1, lh, fsh and testosterone. from the results of the current study, it can be concluded that the levels of gh as well as the levels of igf-1 and igfbp-3, have significant difference between the nghd and the patients’ group. keywords: insulin like growth factor-1, insulin-like growth factor binding protein. received on 30/09/2022, received in revised form on 14/11/2022, accepted on 17/11/2022, published on 30/03/2023 https://doi.org/10.31699/ijcpe.2023.1.10 1introduction growth factor similar to insulin i (igf-i) is a crucial growth and differentiation factor that is produced in a variety of tissues, particularly the liver, and it is closely related to the growth hormone the pituitary produces [1]. 90% of the circulating hormone is bound by igfbp-3, which binds igf-1 specifically and lengthens its half-life [2]. additionally, insulin-like growth factor 1 exerts strong metabolic, insulin-like effects on lipid and carbohydrate metabolism. igf-i probably has a significant impact on how well the central nervous system works as well [3]. igf-1 is a powerful neurotrophic and neuroprotective factor that promotes the proliferation, survival, and growth of neurons in the brain. a wide range of functions, including proliferative, mitochondrial protection, cell survival, tissue growth and development, antiinflammatory and antioxidant, antifibrogenic, and antiaging, have recently been linked to igf-i [4 6]. igfi is thought to be crucial for skeletal development and serves as a sign of the patient's nutritional condition because it declines during hunger [7]. aging and decreasing circulating levels of igf-1 are associated with a number of illnesses, including cardiovascular disease, metabolic syndrome, and neurological disorders [8]. a set of soluble, high-affinity igf-binding proteins (igfbps) tightly govern how igfs interact with igf receptors to prevent the unintended effects of igfs, such as hypoglycemia and unchecked cellular growth. one of three processes—binding of igfbps to molecules in the extracellular matrix, phosphorylation of igfbps, or proteolytic destruction of igfbps—leads to its release from its binding proteins [9]. in addition to the hepatocytes, the kidney, stomach, uterus, and placenta all manufacture igfbp-3 through the sinusoid epithelial cells of the liver. age, nutrition, and gh all affect how much of it is produced [10]. it is in charge of a variety of bodily functions, but those that are related to igf regulation include the movement of igfs in plasma, the management and control of their clearance from the vascular space, the targeting of igfs for specific tissues, and the modification of their interactions with their receptors [11]. igfbp-3 is believed to be associated with the retinoid acid x receptor alpha and hence affect gene expression in an igf independent manner [12]. steroid hormones that interact with vertebrate steroid hormone receptors are known as sex hormones. androgens, estrogens, and progestogens are the sex hormones. male secondary sexual traits are caused by androgens, which are produced in the testicles, ovaries, http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:athraafalah@gmail.com http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/ijcpe.2023.1.10 a. f. hasan et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 89 95 90 and adrenal glands during puberty in both males and females [13]. androgens are also present in females, yet in less amounts. they play a role in desire and sexual excitement, and they also prevent early uterine contraction in pregnant women by relaxing the myometrium's muscles. and in both men and women, they serve as the building blocks for estrogens [14]. estrogen plays a variety of impacts on metabolism, behavior, cardiovascular health, and bone density, all of which have an impact on reproduction in both males and females [15]. however, nongonad organs such the liver, heart, skin, and brain can also create a negligible but considerable amount of estrogens. estrogen is principally produced in the ovaries, corpus luteum, and placenta [16]. regarding the reproductive system, estrogen induces the thickening of the vaginal wall and the maintenance of vasculature and skin. it also stimulates uterine and endometrial growth and vaginal lubrication. the midcycle ovulation is brought on by an increase in luteinizing hormone, which is stimulated by an increase in estrogen [17]. another sex hormone that is primarily found in females is progesterone. progesterone can be produced by the gonads or the adrenal glands, and the progesterone produced by the ovaries is primarily transported in the blood to carry out its biological function, whereas progesterone produced by the adrenal glands is largely converted into glucocorticoids and androgens, allowing the endometrium to transition from a proliferative to a secretory stage. progesterone also appears to have an inhibitory effect on female [18]. the gonadotropins are peptide hormones that control the activity of the ovary and the testicles and are crucial for healthy development, sexual development, and reproduction. follicle-stimulating hormone (fsh) and luteinizing hormone are two of the human gonadotropins produced by the pituitary (lh) [19]. the hypothalamus, the pituitary, and the gonads are all components of the neurological pathway that luteinizing hormone is a part of. pulsatile gnrh production from the hypothalamus triggers the release of lh. numerous neurotransmitters, including dopamine, serotonin, norepinephrine, glutamate, opiate, and galanin, regulate gnrh in its own body. kisspeptin is an essential gnrh regulator, lh generally aids in the maturation of progenitor cells. lh stimulates the production of testosterone in the testes' leydig cells in men, lh causes the ovaries to produce steroid hormones in females [20]. the regulation of testosterone synthesis in male fetuses shifts from hcg-influenced to lh-driven about weeks 15 to 20 of gestation. as with lh, the production of follicle stimulating hormone is negatively influenced by estrogen levels in females. the most important factor in determining the size of the testicles in young boys is sertoli cell growth, which is stimulated by fsh in males. by encouraging granulosa cells in the ovarian follicles to create aromatase, which transforms androgens produced by the thecal cells into estradiol, fsh is responsible for estrogen synthesis in females. when the menstrual cycle is in the follicular phase, it is also in charge of follicular development [20]. 2materials and methods 2.1. patients’ selection this cross-sectional study was carried out in the national diabetic center for treatment and research/almustansiriya university in baghdad/iraq for the period from november 2021 to april 2022, after ethical consent obtained from the review board and a verbal consent of participation from the subjects, the study included 180 subjects that suffer from short stature were divided according to their gh level into the groups: 100 patients suffering from growth hormone deficiency (patients’ group) 80 of disease-free subjects (non-growth hormone deficient group). the inclusion criteria: short statured children aged 3-18 years old, and exclusion criteria this study excluded elderly participants, kids with diabetes, liver or kidney problems, and kids on cortisone, thyroxin, or estrogen drugs. 2.2. collection of samples and measurement of parameters based on the patient's medical history, physical and clinical examination, and gh-igf-1 axis biochemical tests, the diagnosis of ghd was made. the research's parameters will be igf-1, igfbp-3, fsh, lh, and testosterone. five milliliters of blood were drawn, and it was centrifuged for ten minutes at 3000 rpm. age was taken and body mass index of the studied subjects was measured by the following equation: bmi=(body weight)/(hight^2) then it was categorized to underweight (<5th percentile), normal (5th-85th percentile), and overweight (>85th percentile). one-step sandwich chemiluminescence immunoassay was used to assess the presence of insulin-like growth factor. after a series of reactions, isoluminol conjugate was formed, which could then be detected using a photomultiplier such as rlu [21]. using the quantitative sandwich immunoassay method, the amount of insulinlike growth factor binding protein is determined, concentration of follicular stimulating hormone and luteinizing hormone. the hormone testosterone was measured using the competitive binding approach, which produces a yellow product that corresponds to the hormone's concentration as determined by the standard curve [22, 23]. 2.3. statistical analysis statistical analysis was done using spss 23 using the means and standard deviation, t-test, chi square, correlation and analysis of variances, accordingly. p value was considered significant if less than 0.005. 3results and discussion in this study, 76 male participants were studied, 44 of which were gh deficient while the remaining were of the a. f. hasan et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 89 95 91 non-growth hormone deficient group (nghd), 56 females participants had the disease and another 48 were of the nghd group (disease free), the distribution of studied groups according to gender showed no significance correlation using the chi square test at the significance level of 0.05 (table 1). table 1. groups distribution according to age and bmi parameter groups growth hormone deficiency (ghd) non-growth hormone deficient (nghd) gender number percentage number percentage male 44 44% 32 40% female 56 56% 48 60% bmi underweight 81 81% 72 90% normal weight 15 15% 8 10% overweight 4 4% obese no significant difference using chi-square test at 0.05 level. these results were found to be in accordance to those by claessen et al., 2013 [24]. however, studies by [25, 26] found a prominent male predominance in patients being treated for this disease, probably because of the increased search for diagnosis of short stature among males than those among females. the table also shows the distribution of groups according to bmi that was also found to be non significant. the same results were reported by other researcher [27]. who revealed that the most of ghd were underweight. these findings could be due to a variety of factors, including socioeconomic level, hunger, and way of living. the non-growth hormone deficiency had a higher prevalence of normal weight than the ghd patients. gender was not found to be significantly affecting the level of igf-1 or igfbp-3, as shown in (table 2). table 2. effect of gender on levels of igf-1 and igfbp-3 parameter mean ± std p-value male female igf_1 132.275±13.757 121.542±10.224 0.52 igfbp_3 9.7388±0.36249 8.8772±0.30377 0.07 higher level of igf-1 was found in females in a study done by [28]. which opposes our study. no difference in igfbp-3 between males and females, as in our study, in the study done by esberg et al,.2004 [29]. direct factors like protein-calorie intake, catabolic stressors, thyroxine, insulin, binding affinity of the acid-labile subunit for igfi/igfbp-3, zinc, parathyroid hormone, parathyroid hormone-related peptide, and platelet-derived growth factor can all have an impact on the level of circulating igf-i. igf-i levels in youngsters are similar in prepubescent boys and girls [30]. even after tanner stage correction, igf-i levels vary during puberty [30]. these differences are thought to be primarily impacted by gh state, which may then be influenced by sex hormones. this theory has been supported by evidence showing that healthy young females' igf-i levels alter over the menstrual cycle. additionally, it has been demonstrated that blood igf-i levels in healthy midlife adults are only moderately predicted by gh status [31], and the finding that some hypopituitary people with overt ghd have normal igf-i levels strongly suggests that circulating igf-i also depends on factors unrelated to gh. in table 3, shows the effect of gender on lh, fsh, and testosterone, and it was found that there were no significant differences between the first two with p values of (0.01, 0.5), respectively. while testosterone showed a significant difference between males and females with p value being 0.02. in accordance with our study, both of lh and fsh were found to not be significantly different between males and females in a study conducted by roper et al., 2015 [32]. table 3. effect of gender on lh, fsh, and testosterone parameter mean ± std p-value males females lh 39.2437±0.28405 38.0108±0.36053 0.01 fsh 9.2925±0.21986 9.0557±0.35329 0.5 testosterone 1.1238±0.02470 1.0310±0.03046 0.02 testosterone, as it is the main sex hormone in males, was hence found to be higher in males than in females, in our study and in others done by durdiakova et al., 2011 [33]. puberty is a complex process that helps children mature, develop secondary sexual traits, and learn how to reproduce. normal pubertal transition is triggered by central processes, with increased gnrh and gonadotropin production driving the gonadal function. furthermore, it appears that a sufficient energy supply and nutritional balance are necessary for the central beginning of the pubertal shift. at the testicular level, gh stimulates gametogenesis and the generation of steroid hormones during puberty and the reproductively mature phase, as well as the growth and development of the gonad during infancy and adolescence. with increasing age, the rate of gh synthesis doubles, reaches a maximal peak during pubertal maturation, and thereafter declines [34]. the igf-1 released in response to circulating gh levels also supports this mechanism. studies that have revealed how testicular volume changes when patients with childhood-onset growth hormone deficit (co-ghd) are treated with replacement dosages of gh [2], provide evidence to support this. additionally, gh encourages the growth and differentiation of internal testicular anatomy, including seminiferous tubules (st). in table 4 showing the correlations between igfbp-3 and igf-1, lh, fsh and testosterone were positive in the patients group. a. f. hasan et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 89 95 92 table 4. association of igf-1 and igfbp-3 with studied parameters parameter igf-1 igfbp-3 r p r p age 0.498** 0.000 .088 .382 bmi 0.229* 0.022 -.052 .608 igf-1 .277** .005 igfbp_3 0.277** 0.005 lh 0.036 0.724 .353** .000 fsh 0.075 0.461 .508** .000 testosterone 0.147 0.145 .349** .000 in our study, age was found to be negatively correlated with the level of igf-1 this agreement with a study by gubbi et al., 2018 [35]. which is probably because of increased age range included in their study. in accordance with our study, bmi was found to be positively associated with igf-1 level in the study of lewitt et al., 2014 [36]. two other studies showed the positive correlation between igfbp3 with igf-1 [37, 38]. luteinizing hormone was also found to be in a positive association with the level of igfbp-3 by adam et al., 2000 [39]. on the other hand, fsh showed a negative correlation with igfbp-3 by adachi et al., 1995 [40], and testosterone was suggested to have a positive correlation in the study of gross et al., 2004 [41]. since plasma igf-1 concentration has been reported to decrease with age, this suggests that there is a decline in protein synthesis capacity in many tissues with aging, including the liver, skeletal muscle, brain, and bone. this decline is closely associated with changes in igf-1 and may be caused by changes in igf-1 secretion, igf-1 mrna levels, or changes in the regulation of igf-1 binding proteins. the age range of the samples in our study could be the cause of the opposite outcome in this area. the biological consequences of mild dietary restriction prevent the age-related decline in protein synthesis and subsequent igf-1 depletion while still delivering vital nutrients. hyperinsulinemia due to obesity reduce igf1 binding protein and subsequently increase igf1 free concentrations. thus, obesity may highly dysregulate igf1 system despite the reduction of growth hormone [42]. obesity-related hyperinsulinemia decreases igf1 binding protein and hence raises igf1 free concentrations. thus, despite the decrease in growth hormone, obesity may have a significant dysregulation of the igf1 pathway [42]. without a pathogenic cause, the concentration of igf-1 is highly correlated with the levels of its binding proteins in order to control its function and half-life across the human tissues. this is because igf-1 and igfbp-3 levels are typically in balance [20]. it is hypothesized that endogenous igf-i may function as a stimulatory metabolic signal to the pubertal ovine hypothalamo-pituitary axis because exogenous igf-i has been found to stimulate luteinizing hormone (lh) secretion. in adults, fsh and testosterone promote igfbp-3 proteolysis to improve igf-1 activity for maturation of germ cells, which may not be the case in the age group included in this study [14]. 4conclusion from the results of the current study, it can be concluded that the levels of gh as well as the levels of igf-1 and igfbp-it have significant difference between the nghd and the patients’ group , also the levels of lh, fsh and testosterone hormones among the studied groups have high significant difference ,in addition it's found that insulinlike growth factor 1 and insulin like growth factor binding protein are highly correlated growth hormone , luteinizing hormone, and follicular stimulating hormone while testosterone were highly associated with the level of growth hormone ,finally it seems that measurement of growth hormone alone is not enough to diagnose or exclude the disease of growth hormone deficiency and should be coupled with other parameters. references [1] z. laron, “insulin-like growth factor 1 (igf-1): a growth hormone,” mol. pathol., vol. 54, no. 5, p. 311, 2001, http://dx.doi.org/10.1136/mp.54.5.311. [2] c. ohlsson et al., “the role of liver-derived insulinlike growth factor-i,” endocr. rev., vol. 30, no. 5, pp. 494–535, 2009, https://doi.org/10.1210/er.2009-0010. [3] c. a. bondy and c. m. cheng, “signaling by insulinlike growth factor 1 in brain,” eur. j. pharmacol., vol. 490, no. 1–3, pp. 25–31, 2004, https://doi.org/10.1016/j.ejphar.2004.02.042. [4] j. e. puche, m. garcía-fernández, j. muntane, j. rioja, s. gonzalez-baron, and i. castilla cortazar, “low doses of insulin-like growth factor-i induce mitochondrial protection in aging rats,” endocrinology, vol. 149, no. 5, pp. 2620–2627, 2008, https://doi.org/10.1210/en.2007-1563. [5] m. garcía-fernández, j. e. puche, g. delgado, s. gonzález-barón, and i. castilla-cortázar, “149 insulin-like growth factor-i (igf-i) reduces the impact of age in oxidative liver damage and restores insulin resistance and lipid metabolism,” j. hepatol., no. 48, pp. s65–s66, 2008, http://doi.org/10.1016/s0168-8278(08)60151-8. [6] n. a. d. al-garawi, a. a. suhail, h. a. kareem, and g. s. bustani, “study of lipid profile and leptin hormone and adiponectin hormone hypertensive patients in najaf governorate,” rev. electron. vet., pp. 45–51, 2022. [7] j. wang, j. zhou, c. m. cheng, j. j. kopchick, and c. a. bondy, “evidence supporting dual, igf-iindependent and igf-i-dependent, roles for gh in promoting longitudinal bone growth,” j. endocrinol., vol. 180, no. 2, pp. 247–256, 2004, https://doi.org/10.1677/joe.0.1800247. [8] r. c. baxter, “insulin-like growth factor (igf)binding proteins: interactions with igfs and intrinsic bioactivities,” am. j. physiol. metab., vol. 278, no. 6, pp. e967–e976, 2000, https://doi.org/10.1152/ajpendo.2000.278.6.e967. http://dx.doi.org/10.1136/mp.54.5.311 https://doi.org/10.1210/er.2009-0010 https://doi.org/10.1016/j.ejphar.2004.02.042 https://doi.org/10.1210/en.2007-1563 http://dx.doi.org/10.1016%2fs0168-8278(08)60151-8 https://www.veterinaria.org/index.php/redvet/article/view/174 https://www.veterinaria.org/index.php/redvet/article/view/174 https://www.veterinaria.org/index.php/redvet/article/view/174 https://www.veterinaria.org/index.php/redvet/article/view/174 https://www.veterinaria.org/index.php/redvet/article/view/174 https://doi.org/10.1677/joe.0.1800247 https://doi.org/10.1152/ajpendo.2000.278.6.e967 a. f. hasan et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 89 95 93 [9] s. varma shrivastav, a. bhardwaj, k. a. pathak, and a. shrivastav, “insulin-like growth factor binding protein-3 (igfbp-3): unraveling the role in mediating igf-independent effects within the cell,” front. cell dev. biol., vol. 8, p. 286, 2020, https://doi.org/10.3389/fcell.2020.00286. [10] k. a. marzec, r. c. baxter, and j. l. martin, “targeting insulin-like growth factor binding protein3 signaling in triple-negative breast cancer,” biomed res. int., vol. 2015, 2015, https://doi.org/10.1155/2015/638526. [11] f.-m. chen and y. jin, “periodontal tissue engineering and regeneration: current approaches and expanding opportunities,” tissue eng. part b rev., vol. 16, no. 2, pp. 219–255, 2010, https://doi.org/10.1089/ten.teb.2009.0562. [12] n. r. carlson, “physiology of behavior. reproductive behavior.” pearson, 2012. [13] v. a. randall, “androgens and hair,” in testosterone, springer, 1998, pp. 169–186, https://doi.org/10.1007/978-3-642-72185-4_5. [14] g. manukyan et al., “17β-estradiol promotes proinflammatory and procoagulatory phenotype of innate immune cells in the presence of antiphospholipid antibodies,” biomedicines, vol. 8, no. 6, p. 162, 2020, https://doi.org/10.3390/biomedicines8060162. [15] j. cui, y. shen, and r. li, “estrogen synthesis and signaling pathways during aging: from periphery to brain,” trends mol. med., vol. 19, no. 3, pp. 197– 209, 2013, https://doi.org/10.1016/j.molmed.2012.12.007. [16] h. zhang, k. taya, k. nagaoka, m. yoshida, and g. watanabe, “neonatal exposure to 17α-ethynyl estradiol (ee) disrupts follicle development and reproductive hormone profiles in female rats,” toxicol. lett., vol. 276, pp. 92–99, 2017, https://doi.org/10.1016/j.toxlet.2017.05.014. [17] g. jasienska, s. f. lipson, p. t. ellison, i. thune, and a. ziomkiewicz, “symmetrical women have higher potential fertility,” evol. hum. behav., vol. 27, no. 5, pp. 390–400, 2006, https://doi.org/10.1016/j.evolhumbehav.2006.01.001. [18] s. taraborrelli, “physiology, production and action of progesterone,” acta obstet. gynecol. scand., vol. 94, pp. 8–16, 2015, https://doi.org/10.1111/aogs.12771. [19] d. nedresky and g. singh, “physiology, luteinizing hormone,” in statpearls, statpearls publishing, 2021. [20] s. ilahi and t. b. ilahi, “anatomy, adenohypophysis (pars anterior, anterior pituitary),” in statpearls, statpearls publishing, 2021. [21] m. j. horney, inhibition of insulin-like growth factor (igf)-1 by igf binding protein-2: functional and structural aspects. medical university of south carolina, 2001. [22] a. pasqualini et al., “efficacy, safety, and immunogenicity of a biosimilar recombinant human follicle-stimulating hormone (folitime®) vs. gonalf® in women undergoing ovarian stimulation for ivf: a randomized, multicenter, evaluator-blinded, non-inferiority study,” jbra assist. reprod., vol. 25, no. 4, p. 524, 2021, http://doi.org/10.5935/15180557.20210023. [23] s. vafaei, f. motejaded, and a. ebrahimzadehbideskan, “protective effect of crocin on electromagnetic field-induced testicular damage and heat shock protein a2 expression in male balb/c mice,” iran. j. basic med. sci., vol. 23, no. 1, p. 102, 2020, http://doi.org/10.22038/ijbms.2019.38896.9229. [24] k. m. j. a. claessen et al., “metabolic profile in growth hormone-deficient (ghd) adults after longterm recombinant human growth hormone (rhgh) therapy,” j. clin. endocrinol. metab., vol. 98, no. 1, pp. 352–361, 2013, https://doi.org/10.1210/jc.20122940. [25] s. e. myers, b. y. whitman, a. l. carrel, v. moerchen, m. t. bekx, and d. b. allen, “two years of growth hormone therapy in young children with prader–willi syndrome: physical and neurodevelopmental benefits,” am. j. med. genet. part a, vol. 143, no. 5, pp. 443–448, 2007, https://doi.org/10.1002/ajmg.a.31468. [26] a. l. carrel, v. moerchen, s. e. myers, m. t. bekx, b. y. whitman, and d. b. allen, “growth hormone improves mobility and body composition in infants and toddlers with prader-willi syndrome,” j. pediatr., vol. 145, no. 6, pp. 744–749, 2004, https://doi.org/10.1016/j.jpeds.2004.08.002. [27] m. brada, s. ashley, d. ford, d. traish, l. burchell, and b. rajan, “cerebrovascular mortality in patients with pituitary adenoma,” clin. endocrinol. (oxf)., vol. 57, no. 6, pp. 713–717, 2002, https://doi.org/10.1046/j.1365-2265.2002.01570.x. [28] w. liu et al., “zihuai recipe alleviates cyclophosphamide-induced diminished ovarian reserve via suppressing pi3k/akt-mediated apoptosis,” j. ethnopharmacol., vol. 277, p. 113789, 2021, https://doi.org/10.1016/j.jep.2021.113789. [29] l. b. esberg, x. zhang, g. i. scott, b. culver, and j. ren, “impact of gender on basal and insulin-like growth factor i-regulated nitric oxide synthase activity in adult rat left ventricular myocytes,” comp. biochem. physiol. part a mol. integr. physiol., vol. 138, no. 2, pp. 141–146, 2004, https://doi.org/10.1016/j.cbpb.2004.02.022. [30] m. toumba, a. albanese, c. azcona, and r. stanhope, “effect of long-term growth hormone treatment on final height of children with russellsilver syndrome,” horm. res. paediatr., vol. 74, no. 3, pp. 212–217, 2010, https://doi.org/10.1159/000295924. https://doi.org/10.3389/fcell.2020.00286 https://doi.org/10.1155/2015/638526 https://doi.org/10.1089/ten.teb.2009.0562 https://doi.org/10.3390/biomedicines8060162 https://doi.org/10.1016/j.molmed.2012.12.007 https://doi.org/10.1016/j.toxlet.2017.05.014 https://doi.org/10.1016/j.evolhumbehav.2006.01.001 https://doi.org/10.1111/aogs.12771 https://europepmc.org/article/nbk/nbk539692#free-full-text https://europepmc.org/article/nbk/nbk539692#free-full-text https://www.ncbi.nlm.nih.gov/books/nbk519039/ https://www.ncbi.nlm.nih.gov/books/nbk519039/ https://www.ncbi.nlm.nih.gov/books/nbk519039/ https://www.proquest.com/openview/26042c9f550bdcfcef1a669c0718b9ba/1?pq-origsite=gscholar&cbl=18750&diss=y https://www.proquest.com/openview/26042c9f550bdcfcef1a669c0718b9ba/1?pq-origsite=gscholar&cbl=18750&diss=y https://www.proquest.com/openview/26042c9f550bdcfcef1a669c0718b9ba/1?pq-origsite=gscholar&cbl=18750&diss=y https://www.proquest.com/openview/26042c9f550bdcfcef1a669c0718b9ba/1?pq-origsite=gscholar&cbl=18750&diss=y https://doi.org/10.5935%2f1518-0557.20210023 https://doi.org/10.5935%2f1518-0557.20210023 https://doi.org/10.22038%2fijbms.2019.38896.9229 https://doi.org/10.1210/jc.2012-2940 https://doi.org/10.1210/jc.2012-2940 https://doi.org/10.1002/ajmg.a.31468 https://doi.org/10.1016/j.jpeds.2004.08.002 https://doi.org/10.1046/j.1365-2265.2002.01570.x https://doi.org/10.1016/j.jep.2021.113789 https://doi.org/10.1016/j.cbpb.2004.02.022 https://doi.org/10.1159/000295924 a. f. hasan et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 89 95 94 [31] a. giustina et al., “criteria for cure of acromegaly: a consensus statement,” j. clin. endocrinol. metab., vol. 85, no. 2, pp. 526–529, 2000, https://doi.org/10.1210/jcem.85.2.6363. [32] l. k. roper, j. s. briguglio, c. s. evans, m. b. jackson, and e. r. chapman, “sex-specific regulation of follicle-stimulating hormone secretion by synaptotagmin 9,” nat. commun., vol. 6, no. 1, pp. 1–10, 2015, https://doi.org/10.1038/ncomms9645. [33] j. durdiakova, d. ostatnikova, and p. celec, “testosterone and its metabolites—modulators of brain functions.,” acta neurobiol. exp. (wars)., 2011. [34] j. e. puche and i. castilla-cortázar, “human conditions of insulin-like growth factor-i (igf-i) deficiency,” j. transl. med., vol. 10, no. 1, pp. 1–29, 2012, https://doi.org/10.1186/1479-5876-10-224. [35] s. gubbi, g. f. quipildor, n. barzilai, d. m. huffman, and s. milman, “40 years of igf1: igf1: the jekyll and hyde of the aging brain,” j. mol. endocrinol., vol. 61, no. 1, pp. t171–t185, 2018. [36] m. s. lewitt, m. s. dent, and k. hall, “the insulinlike growth factor system in obesity, insulin resistance and type 2 diabetes mellitus,” j. clin. med., vol. 3, no. 4, pp. 1561–1574, 2014, https://doi.org/10.3390/jcm3041561. [37] t. e. hormones and b. c. c. group, “insulin-like growth factor 1 (igf1), igf binding protein 3 (igfbp3), and breast cancer risk: pooled individual data analysis of 17 prospective studies,” lancet oncol., vol. 11, no. 6, pp. 530–542, 2010, https://doi.org/10.1016/s1470-2045(10)70095-4. [38] y. wang, h. zhang, m. cao, l. kong, and x. ge, “analysis of the value and correlation of igf‑1 with gh and igfbp‑3 in the diagnosis of dwarfism,” exp. ther. med., vol. 17, no. 5, pp. 3689–3693, 2019, https://doi.org/10.3892/etm.2019.7393. [39] c. l. adam, t. s. gadd, p. a. findlay, and d. c. wathes, “igf-i stimulation of luteinizing hormone secretion, igf-binding proteins (igfbps) and expression of mrnas for igfs, igf receptors and igfbps in the ovine pituitary gland,” j. endocrinol., vol. 166, no. 2, pp. 247–254, 2000, http://doi.org/10.1677/joe.0.1660247. [40] t. adachi, m. iwashita, a. kuroshima, and y. takeda, “regulation of igf binding proteins by fsh in human luteinizing granulosa cells,” j. assist. reprod. genet., vol. 12, no. 9, pp. 639–643, 1995, https://doi.org/10.1007/bf02212589. [41] j. m. gross, “insulin-like growth factor binding protein-1 interacts with integrins to inhibit insulinlike growth factor-induced breast cancer growth and migration,” minnesota univ minneapolis, 2003. [42] p. j. wysocki and b. wierusz-wysocka, “obesity, hyperinsulinemia and breast cancer: novel targets and a novel role for metformin,” expert rev. mol. diagn., vol. 10, no. 4, pp. 509–519, 2010, https://doi.org/10.1586/erm.10.22. https://doi.org/10.1210/jcem.85.2.6363 https://psycnet.apa.org/record/2012-10457-003 https://psycnet.apa.org/record/2012-10457-003 https://psycnet.apa.org/record/2012-10457-003 https://psycnet.apa.org/record/2012-10457-003 https://doi.org/10.3390/jcm3041561 https://doi.org/10.1016/s1470-2045(10)70095-4 https://doi.org/10.1677/joe.0.1660247 https://apps.dtic.mil/sti/citations/ada420347 https://apps.dtic.mil/sti/citations/ada420347 https://apps.dtic.mil/sti/citations/ada420347 https://apps.dtic.mil/sti/citations/ada420347 https://apps.dtic.mil/sti/citations/ada420347 https://doi.org/10.1586/erm.10.22 a. f. hasan et al. / iraqi journal of chemical and petroleum engineering 24,1 (2023) 89 95 95 ه لشبيهرمون النمو وعامل النمو الشبيه باالنسولين والبروتين الرابط لعامل النمو ا موالن باالنسولين وبعض الهرمونات في االطفال العراقيين الذين يعانون من نقص هرمون 2 عبد الكريم يحيى السامرائيو ،1 بشرى فارس حسن ،* ،1 عذراء فالح حسن ، العراقجامعة بغداد ،كلية العلوم للبنات 1 ، العراقالجامعة المستنصرية ،المركز الوطني للسكري 2 الخالصة دورفي التمثيل الغذائي والنمو في جميع أنحاء الجسم وهو يرتبط بقوة له 1-عامل النمو شبيه االنسولين ن هرمون النمو األنسجة تقريبا، وخاصة الكبد ليكو وينظم بواسطة هرمون النمو، ويتم إنتاجه من قبل أي نوع من في 1-هدفت الدراسة إلى قياس عامل النمو شبيه األنسولين الذي يزيد من نصف عمره. المرتبط بالبروتين موضوعا في 180مرضى نقص هرمون النمو وإيجاد عالقة مع المعلمات األخرى المدروسة. تمت دراسة عالج والبحوث / جامعة المستنصرية في بغداد / العراق للفترة من نوفمبر المركز الوطني لمرضى السكري لل fsh و lh و igfbp-3 و igf-1 . تم سحب الدم والتحقيق فيه لمستويات2022إلى أبريل 2021 والتستوستيرون وتم إجراء تحليل إحصائي للعثور على أي ارتباطات. لم يتم ايجاد تأثير للجنس على مستويات وجد له ارتباط ايجابي مع العمر ومؤشر كتلة الجسم وعامل 1-عامل النمو شبية االنسولينمعلمات. جميع ال وجد له ارتباط 3-. بينما عامل النمو شبيه االنسولين الرابط بالبروتين3-النمو شبيه االنسولين الرابط بالبروتين للحوصلة والهرمون المنشط للجسم وهرمون المحفز 1-مستويات عامل النمو شبية االنسولين عايجابي م والتستيسترون.االصغير .3-لنمو شبيه االنسولين الرابط بالبروتيناعامل ، 1-عامل النمو شبيه االنسولين : الكلمات الدالة